Heat-insulation, sound-insulation and aging-resistant UPVC (unplasticized polyvinyl chloride) pipe and preparation method thereof

Abstract

The invention relates to a heat-insulation sound-insulation aging-resistant UPVC (unplasticized polyvinyl chloride) pipe and a preparation method thereof, and the UPVC pipe is prepared from the following raw materials in parts by weight: 100 parts of polyvinyl chloride resin, 10-15 parts of shape memory polymer, 5-8 parts of hydrated salt microcapsule, 2-3 parts of benzophenone compound, 2-3 parts of 2, 3, 4-trimethyl-1, 3-pentanediol monoisobutyrate and 1-3 parts of 2, 3-pentanediol monoisobutyrate. 1 to 2 parts of 2, 6-butylated hydroxytoluene, 1 to 1.5 parts of hindered amine stabilizer and 0.5 to 1 part of silane coupling agent; the hindered amine stabilizer comprises Tinuvin 622, Chimassorb 944 and a compatilizer, the weight ratio of the Tinuvin 622 to the Chimassorb 944 is 7: (1-5), the shape memory polymer is polystyrene-b-polycaprolactone, the number-average molecular weight of the polystyrene-b-polycaprolactone is 45000-55000 g / mol, the molecular weight ratio of a polystyrene segment is 35-45%, and the molecular weight ratio of a polycaprolactone segment is 55-65%. The polystyrene-b-polycaprolactone, the hindered amine stabilizer and the hydrated salt microcapsules in an accurate proportion are added, and combination of temperature response type heat insulation and long-acting aging resistance is achieved through the synergistic effect of the polystyrene-b-polycaprolactone, the hindered amine stabilizer and the hydrated salt microcapsules, so that the UPVC pipe accidentally obtains enhanced heat insulation, sound insulation and aging resistance.

Description

Technical Field

[0001] The present application relates to the technical field of plastic pipes, and in particular to a UPVC pipe that is heat-insulating, sound-insulating and aging-resistant, and a preparation method thereof. Background Art

[0002] Plastic pipe technology plays a vital role in modern industry and life, and its application is expanding with the continuous development of society. UPVC pipe, primarily made of polyvinyl chloride resin, offers advantages such as excellent corrosion resistance, a smooth interior, and low fluid resistance. This has led to its widespread use in a variety of key areas, including building water supply and drainage, and chemical pipeline transportation, significantly boosting the development of related industries. Whether in urban high-rise construction or in the production processes of chemical companies, UPVC pipe plays an indispensable role, promoting the rational allocation and utilization of resources. In the past, improving the thermal insulation performance of ordinary UPVC pipes mostly involved wrapping them with insulation materials, such as wrapping glass wool, rock wool, and other materials around the pipe's outer layer to slow heat transfer. For sound insulation, a common method was to install a soundproofing sleeve on the pipe's exterior. Rubber-based insulation sleeves, for example, provided some sound insulation. To address aging resistance, small amounts of antioxidants or UV absorbers were added during the production process to slow the aging of the pipe due to external factors. These conventional methods can improve the performance of UPVC pipes to a certain extent, but due to their inherent limitations, they cannot fundamentally resolve the problem.

[0003] However, these traditional treatment methods have obvious flaws. Wrapping with insulation materials not only increases construction difficulty and cost, but also has limited insulation effects. This makes it difficult to meet the requirements of some scenarios with high insulation requirements, such as hot water pipelines and drainage pipes on building exterior walls exposed to direct sunlight. This may cause energy waste or affect the normal operation of the piping system. Although sound insulation sleeves can reduce noise to a certain extent, they are not effective in cases where the water flow rate is high, such as when draining high-rise buildings, and will still interfere with the surrounding environment. Adding a small amount of antioxidants or UV absorbers can only alleviate aging problems in the short term. In the long run, UPVC pipes will still be affected by factors such as ultraviolet radiation, temperature changes, and chemical corrosion. Summary of the Invention

[0004] In order to make UPVC pipes have excellent heat insulation, sound insulation and aging resistance, the present application provides a heat insulation, sound insulation and aging resistance UPVC pipe and a preparation method thereof.

[0005] In the first aspect, the present application provides a UPVC pipe that is heat-insulating, sound-insulating and aging-resistant, and adopts the following technical solution: a UPVC pipe that is heat-insulating, sound-insulating and aging-resistant, and its preparation raw materials include the following raw materials in parts by weight: 100 parts of polyvinyl chloride resin, 10-15 parts of shape memory polymer, 5-8 parts of hydrated salt microcapsules, 2-3 parts of benzophenone compounds, 1-2 parts of 2,6-di-tert-butyl-p-cresol, 1-1.5 parts of hindered amine stabilizers and 0.5-1 parts of silane coupling agents; the hindered amine stabilizers include Tinuvin 622, Chimassorb 944 and a compatibilizer, and the Tinuvin 622 and Chimassorb 944 by weight ratio 7: (1-5), the shape memory polymer is polystyrene-b-polycaprolactone, the number average molecular weight of the polystyrene-b-polycaprolactone is 45000-55000 g / mol, of which the molecular weight of the polystyrene segment accounts for 35-45% and the molecular weight of the polycaprolactone segment accounts for 55-65%.

[0006] By adopting the above technical solution, the polystyrene (PS) segment acts as a rigid component, providing structural support for the material and forming a stable layered framework. The polycaprolactone (PCL) segment is temperature-sensitive and softens and expands when the temperature exceeds 40°C, increasing the gaps in the layered structure and forming a porous air insulation layer (the air has low thermal conductivity, blocking heat conduction). At the same time, the porous structure can scatter sound wave energy (sound waves are reflected and dissipated in the pores). The temperature-sensitive phase change of the PCL segment is accompanied by molecular chain movement. The deformation of the material caused by the sound wave vibration converts the sound energy into heat energy (internal friction effect) through the viscoelasticity of PCL, achieving "sound-to-heat" conversion.

[0007] In the polystyrene-b-polycaprolactone used as the raw material for the preparation of UPVC pipes, when the molecular weight of the polystyrene segment accounts for 40% and the polycaprolactone segment accounts for 60%, the UPVC pipe has an excellent shape recovery rate in the temperature range of 25 to 50°C. Usually, the PS (polystyrene) segment is used as the stationary phase, and the increase in its molecular weight will increase the rigidity and entanglement of the molecular chain, and enhance the "memory anchor point" strength of the material at high temperatures. The PCL (polycaprolactone) segment is used as the soft segment, and the decrease in its molecular weight will cause its glass transition temperature (Tg) and melting temperature (Tm) to shift to low temperatures, and the chain segment mobility will be enhanced. However, when the molecular weight of the PS segment is greater than or equal to the molecular weight of the PCL segment, the chain segment mobility will decrease, and the soft segment will not be able to provide sufficient deformation capacity, which will affect the recovery efficiency.

[0008] Hydrated salts (such as sodium sulfate decahydrate) have a fixed phase transition temperature range. When the ambient temperature rises, the hydrated salt melts from a solid to a liquid state, absorbing a large amount of heat without changing temperature (latent heat of phase change). This achieves a "heat-to-energy" conversion, directly reducing temperature accumulation on the surface and within the material. Hydrated salt microcapsules, evenly dispersed within the PS-b-PCL matrix, absorb heat energy generated by viscoelastic losses in the PCL segments, preventing localized overheating that could lead to material performance degradation. They also absorb high-temperature heat from the environment, further enhancing the thermal insulation effect.

[0009] PS-b-PCL drives the "acoustic-to-thermal" conversion, i.e., acoustic vibration → viscoelastic deformation of the PCL → conversion of acoustic energy to thermal energy. Hydrated salt microcapsules drive the "heat-to-energy storage" conversion, i.e., thermal energy generated by the PCL combined with ambient high-temperature heat → absorption by the hydrated salt phase change → storage of this heat within the microcapsules. These two elements work together to create a closed loop of acoustic-thermal-energy storage, preventing thermal energy accumulation from degrading material performance. Furthermore, energy storage reduces ambient heat conduction, enabling a sustainable "acoustic-thermal-energy storage" chain, rather than a single energy loss mechanism.

[0010] The added benzophenone compounds as light stabilizers and 2,6-di-tert-butyl-p-cresol as free radical scavengers form a molecular-level protection network to resist ultraviolet rays and oxidative degradation, while simultaneously improving thermal and oxygen stability and climate applicability.

[0011] Among hindered amine stabilizers, Tinuvin 622 physically binds to the polyvinyl chloride resin matrix through its long-chain structure, improving migration resistance by 70%. Chimassorb 944 rapidly diffuses onto the material surface, capturing early free radicals. Combined in a ratio of 7:1-5, the two stabilizers create a dual "anchoring-diffusion" protection mechanism, reducing the yellowing index of UPVC pipes after UV aging. Silane coupling agents enhance the interfacial bonding between the raw material components, improving the overall performance of the pipe, resulting in UPVC pipes with thermal insulation, sound insulation, and aging resistance.

[0012] In a specific embodiment, the weight ratio of Tinuvin 622 to Chimassorb 944 is 7:3.

[0013] The inventors discovered that a weight ratio of 7:3 for Tinuvin 622 and Chimassorb 944 creates a well-balanced hindered amine stabilizer distribution. This results in a refined particle size within the polyvinyl chloride resin matrix, improving free radical capture efficiency and resulting in superior aging resistance for UPVC pipes compared to other ratios.

[0014] In a specific embodiment, the compatibilizer is maleic anhydride grafted POE, and the weight ratio of the sum of Tinuvin 622 and Chimassorb 944 to the maleic anhydride grafted POE is (1-2):1.

[0015] The inventors found that adding maleic anhydride grafted POE can improve the dispersibility of polystyrene-b-polycaprolactone in polyvinyl chloride matrix, and the elastomeric POE segment improves the interfacial bonding strength between polystyrene-b-polycaprolactone and polyvinyl chloride resin, thereby improving the long-term stability of thermal insulation performance.

[0016] The addition of maleic anhydride-grafted POE also improves the system's melt index and reduces processing torque. It also reduces the decomposition rate of hindered amine stabilizers due to shear heat generation during processing. Furthermore, in a 1000-hour UV aging test, the synergistic system exhibited improved tensile strength retention compared to a system without the addition of a compatibilizer.

[0017] In a specific embodiment, the preparation steps of the hindered amine stabilizer are as follows: Tinuvin 622 and Chimassorb 944 are mixed according to a weight ratio, and a compatibilizer is added, and the mixture is mixed in a high shear mixer at 80-100° C. and 3000-5000 rpm to obtain the hindered amine stabilizer.

[0018] By adopting the above technical solution, Tinuvin 622 and Chimassorb 944 in a specific weight ratio are mixed with a compatibilizer in a high-shear mixer at 80-100°C and a rotation speed of 3000-5000 rpm to prepare a hindered amine stabilizer. This can ensure that the raw materials are fully mixed and reacted, effectively improving the aging resistance of UPVC pipes. At the same time, maleic anhydride-grafted POE as a compatibilizer not only improves the dispersibility of polystyrene-b-polycaprolactone in the polyvinyl chloride matrix, but also improves the interfacial bonding strength between polystyrene-b-polycaprolactone and polyvinyl chloride resin through the elastomeric POE chain segment, which helps to enhance the tensile strength and interface protection of UPVC pipes.

[0019] In a specific embodiment, the benzophenone compound is 2-hydroxy-4-dodecyloxybenzophenone.

[0020] The inventors discovered that by selecting 2-hydroxy-4-dodecyloxybenzophenone as a benzophenone compound, the maximum absorption wavelength (λmax) of UV-571 is approximately 285nm (UV-B band) and 330nm (UV-A band). This covers the UV-B (280-320nm) and part of the UV-A (320-400nm) bands of solar radiation, which are most damaging to polymer materials, and can effectively absorb the key ultraviolet photons that trigger photodegradation. Furthermore, the 2-hydroxyl group (-OH) in the 2-hydroxy-4-dodecyloxybenzophenone (UV-571) molecule can form a six-membered ring intermediate through intramolecular hydrogen bonding, converting the absorbed ultraviolet energy into harmless heat energy release, thus avoiding molecular chain breakage caused by energy accumulation (such as the breakage of the C-C bond of PVC to form conjugated double bonds, which causes yellowing and embrittlement).

[0021] UV-571 and hindered amine stabilizers (HALS) form a dual "absorption-capture" protection mechanism. UV-571 preferentially absorbs UV rays, reducing the generation of excited products and thus reducing the production of free radicals and reactive oxygen species at the source. HALS, on the other hand, captures free radicals generated by UV radiation or other factors, inhibiting chain degradation reactions. The synergistic effect of the two significantly improves anti-aging efficiency.

[0022] The decomposition temperature of UV-571 is much higher than the processing temperature of UPVC pipes. Therefore, it will not lose its effectiveness due to thermal decomposition during the extrusion process, ensuring that its UV absorption capacity is retained intact after processing. The long-chain dodecyloxy groups in the molecule give it low polarity and good compatibility. It has excellent compatibility with components such as UPVC resin and PS-b-PCL shape memory polymer, and can be evenly dispersed in the material, avoiding surface defects or degradation of protective performance due to migration and precipitation.

[0023] UV-571 also synergizes with hydrated salt microcapsules and maleic anhydride-grafted POE to further enhance aging resistance. The latent heat of phase change from the hydrated salt microcapsules mitigates temperature fluctuations between the inside and outside of the pipe, reducing stress concentration caused by sudden temperature changes. UV-571 absorbs ultraviolet light to reduce photo-stress, and together they inhibit "thermal-photosynergistic" aging. Maleic anhydride-grafted POE acts as a compatibilizer, improving the interfacial bonding between UV-571 and PVC resin, avoiding localized weak areas of protection caused by uneven dispersion and enhancing overall protection uniformity.

[0024] In a specific embodiment, the hydrated salt microcapsules are sodium sulfate decahydrate microcapsules, the average particle size of the microcapsules is 10-30 μm, and the capsule wall material is urea-formaldehyde resin.

[0025] By adopting the above technical solution, sodium sulfate decahydrate microcapsules can absorb or release a large amount of heat when reaching the phase change temperature, effectively reducing the thermal conductivity of the pipe and achieving good thermal insulation effect; its specific phase change latent heat and particle size as well as urea-formaldehyde resin capsule wall help to improve the stability and dispersibility of the microcapsules, further enhancing the thermal insulation performance of the pipe, while reducing the impact of temperature changes on the pipe and improving the aging resistance of the pipe.

[0026] In a specific embodiment, the silane coupling agent is KH-570.

[0027] The inventors discovered that maleic anhydride-grafted POE enhances the anchoring effect of KH-570 through physical entanglement, further improving the bonding efficiency of hindered amine stabilizers. The hydrolysis product of KH-570 forms a siloxane coating on the surface of the microcapsules, enhancing the water resistance of the urea-formaldehyde resin capsule wall. The silanol groups of KH-570 form hydrogen bonds with the hydroxyl groups on the surface of benzophenone nanoparticles, refining the dispersed particle size of the nanoparticles in the polyvinyl chloride resin. Furthermore, the lubricating effect of KH-570 improves the melt index of the system and reduces processing energy consumption. Through chemical bonding, interfacial compatibilization, and network structure construction, KH-570 significantly improves the material's aging resistance, mechanical properties, and processing stability.

[0028] In a second aspect, the present application provides a method for preparing a heat-insulating, sound-insulating and aging-resistant UPVC pipe, which adopts the following technical solution: A method for preparing a heat-insulating, sound-insulating and aging-resistant UPVC pipe comprises the following steps: S1: Mixing: Add polyvinyl chloride resin to a high-speed mixer at room temperature, heat to 55-65°C, add polystyrene-b-polycaprolactone, heat to 75-85°C, add hydrated salt microcapsules, heat to 95-105°C, add hindered amine stabilizer, heat to 115-125°C, add KH-570, heat to 125-135°C, add benzophenone compounds, heat to 135-145°C, add 2,6-di-tert-butyl-p-cresol, heat to 145-155°C, keep warm, mix and blend, and extrude and granulate to obtain masterbatch; S2: Casting pipe: The masterbatch is extruded through a single screw extruder, and the extruded material is shaped and cooled in a vacuum shaping box and a multi-stage cooling water tank.

[0029] The inventors discovered that polyvinyl chloride resin, as the main raw material, is first added to the high-speed mixer to form a basic dispersion medium, providing a matrix for the subsequent additives and modifiers to adhere to and disperse. If the polyvinyl chloride resin is added later, the additives will first clump together, making it difficult to evenly distribute in the resin, resulting in local additive concentrations that are too high or too low, affecting the uniformity of pipe performance. In addition, after the polyvinyl chloride resin is added at room temperature, it gradually softens during the mixer's heating process, creating a gradually adaptable temperature environment for the subsequent addition of high-temperature additives. If the high-temperature additive is added first and then the PVC, the additive will prematurely decompose or agglomerate at low temperatures, reducing its efficacy.

[0030] As a block copolymer, polystyrene-b-polycaprolactone has a glass transition temperature of approximately 100°C for the polystyrene segment and approximately 60°C for the polycaprolactone segment. At 60°C, the polyvinyl chloride resin begins to soften (the glass transition temperature of polyvinyl chloride resin is approximately 80°C). Adding polystyrene-b-polycaprolactone at this time can leverage the initial fluidity of the polyvinyl chloride resin matrix and promote the dispersion of the block copolymer within the resin. If added too early (e.g., at room temperature), the polystyrene segment has not softened, easily forming rigid particle agglomerates. If added too late (e.g., after 80°C), the viscosity of the polyvinyl chloride resin increases, making it difficult for polystyrene-b-polycaprolactone to intercalate between resin molecular chains, reducing the toughening and compatibility effects.

[0031] High-speed stirring combined with temperature gradient can fully expand the block structure of polystyrene-b-polycaprolactone under shear force, thereby enhancing the toughening effect on polyvinyl chloride resin; hydrated salt microcapsules are evenly dispersed in the resin gaps to form a "micro-airbag" network that is heat-insulating and sound-insulating; stabilizers and coupling agents form chemical bonds (such as silicon-oxygen bonds and hydrogen bonds) between the molecular chains of polyvinyl chloride resin through dynamic thermal motion, rather than physical adsorption, thereby improving aging resistance and durability.

[0032] The raw materials are batched and mixed so that they are fully mixed and evenly dispersed, ensuring a more reasonable distribution of the components in the final UPVC pipe, thereby improving its thermal insulation, sound insulation and aging resistance. At the same time, the screw speed and traction speed are adjusted according to the pipe diameter for extrusion molding and subsequent processing, which can make the pipe better meet the actual specification requirements and improve the stability of product quality.

[0033] In a specific embodiment, the silane coupling agent needs to be hydrolyzed and activated with an ethanol aqueous solution (volume ratio 1:1) under acidic conditions (pH 4-5) before use.

[0034] The inventors discovered that hydrolysis activation of KH-570 requires acidic conditions (pH 4-5) in a water-ethanol system to generate silanol groups (-SiOH). At 120°C, the polyvinyl chloride resin matrix has a certain degree of fluidity. These silanol groups can undergo a condensation reaction with the chlorine atoms on the polyvinyl chloride resin molecular chain, simultaneously forming silicon-oxygen bonds with fillers (such as the surface of microcapsules), acting as a "bridging" agent.

[0035] In a specific embodiment, in step S1, the mixing speed of the high-speed mixer is 800-1000 rpm, and the heat preservation and mixing time is 15-20 minutes.

[0036] By adopting the above technical solution, since mixing uniformity directly affects material properties, too low a rotation speed may lead to uneven dispersion of fillers.

[0037] In summary, this application includes at least one of the following beneficial technical effects: 1. This application utilizes polystyrene-b-polycaprolactone as a shape memory polymer, achieving functional coupling through molecular design. While the polystyrene segments provide a rigid framework for the phase-change system, the polycaprolactone segments soften and expand at temperatures above 40°C, forming a porous structure. This structure not only creates an air insulation layer but also absorbs sound wave energy through viscoelastic losses. Combined with the phase-change energy storage effect of the hydrated salt microcapsules, this creates a complementary "structural insulation-phase-change heat absorption" function, achieving the simultaneous reduction of thermal conductivity and improvement of sound insulation.

[0038] 2. In this application, 2-hydroxy-4-dodecyloxybenzophenone is used to absorb ultraviolet light energy, 2,6-di-tert-butyl-p-cresol is used to scavenge initial oxidative free radicals, and Tinuvin 622 and Chimassorb 944 are compounded in a ratio of 7:3 to form an "anchoring-diffusion" mechanism, which reduces the yellowing index of UPVC pipes after ultraviolet aging and improves the aging resistance of UPVC pipes.

[0039] 3. The method of the present application can reduce the thermal conductivity of UPVC pipes and improve sound insulation by precisely controlling the order of adding raw materials, thereby achieving synergistic optimization of heat insulation, sound insulation and aging resistance. DETAILED DESCRIPTION

[0040] The present application is further described in detail below with reference to the following examples and comparative examples: Some of the raw materials used in the preparation examples, embodiments and comparative examples: Polyvinyl chloride resin, model NP50, was purchased from Changping Polymer Plastics Raw Materials Management Department, Dongguan City; polystyrene-b-polycaprolactone, product number Q-001277, was purchased from Xi'an Qiyue Biotechnology Co., Ltd.; Tinuvin 622 (CAS number: 65447-77-0) and Chimassorb 944 (CAS No.: 71878-19-8) were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; maleic anhydride grafted POE, model W1F, was purchased from Coase Chemical Co., Ltd.; sodium sulfate decahydrate (CAS No.: 7727-73-3) was purchased from Sinopharm Chemical Reagent Co., Ltd.; sodium dodecyl sulfate (SDS) (CAS No.: 151-21-3) was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; urea-formaldehyde resin prepolymer (solid content 50%), brand UF-50, was purchased from Shandong Shengao Chemical Technology Co., Ltd.; 2-hydroxy-4-dodecyloxybenzophenone (UV-571) (CAS No.: 2985-59-3) was purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; 2,6-di-tert-butyl-p-cresol (CAS No.: 128-37-0) was purchased from Juye Runjia Chemical Co., Ltd.

[0041] The raw materials used in the preparation examples, embodiments and comparative examples that are not otherwise specified are all conventional products that can be purchased on the market.

[0042] Preparation Example 1 Preparation steps of sodium sulfate decahydrate microcapsules: 1. Raw material preparation Preparation of core material: Weigh 500 g of sodium sulfate decahydrate, grind into powder, and pass through a 100-mesh sieve for later use.

[0043] Preparation of wall material solution: Weigh 125g of urea-formaldehyde resin prepolymer (50% solid content), add 80-100mL of deionized water, and stir until completely dissolved. Adjust the pH to 4.0 with 10% citric acid solution to form an acidic wall material solution. Emulsifier preparation: Weigh 1.5 g of sodium dodecyl sulfate (SDS) and dissolve it in 50 mL of deionized water to prepare an emulsifier solution. 2. Pre-emulsification process: core material dispersion: add sodium sulfate decahydrate powder into the emulsifier solution, stir and disperse at a speed of 3000 rpm for 15 minutes to form a uniform water suspension. Initial emulsification: slowly add the wall material solution, maintain the stirring speed at 2000 rpm, and emulsify for 30 minutes to form a stable O / W emulsion. 3. Microcapsule polymerization reaction at constant temperature: the emulsion was transferred to a three-necked flask, placed in a constant temperature water bath at 40°C, and mechanically stirred (800 rpm). Cross-linking and curing: 10% ammonia water was added dropwise to adjust the pH to 7.0 to initiate cross-linking polymerization of urea-formaldehyde resin and the reaction was continued for 4 hours. Heat preservation and aging: After the reaction is completed, the temperature is maintained at 35°C and stirring is continued for aging for 2 hours to promote the densification of the capsule wall. 4. Microcapsule separation and purification Centrifugation: Transfer the reaction solution to a centrifuge tube, centrifuge at 5000 rpm for 15 min, and collect the precipitate. Washing treatment: Wash the precipitate with deionized water and anhydrous ethanol three times each to remove unreacted monomers and emulsifiers. Drying treatment: The washed microcapsules were placed in a vacuum drying oven and dried at 40° C. for 24 hours to obtain powdered sodium sulfate decahydrate microcapsules. Example

[0044] Example 1 A method for preparing a heat-insulating, sound-insulating and aging-resistant UPVC pipe comprises the following steps: S1. Preparation of hindered amine stabilizer: 5.25 parts of Tinuvin 622 and 2.25 parts of Chimassorb 944 were poured into the cavity of the reactor, 5 parts of maleic anhydride-grafted POE were added, and premixed at room temperature for 2 minutes at a speed of 1000 rpm; the heating system of the high shear mixer was started, and the temperature was increased to 100°C at a speed of 5°C / min. After reaching the set temperature, the speed was increased to 5000 rpm, and mixing was carried out at a constant temperature and speed for 15 minutes; after the mixing was completed, the temperature was cooled to below 60°C and discharged to obtain the hindered amine stabilizer.

[0045] S2. Mixing: Start the high-speed mixer at 900 rpm, add 1000 parts of polyvinyl chloride resin to the high-speed mixer at room temperature, heat it to 60°C at a heating rate of 5°C / min, add 125 parts of polystyrene-b-polycaprolactone, and continue stirring at this temperature for 10 minutes; heat it to 80°C at a heating rate of 3°C / min, add 65 parts of sodium sulfate decahydrate microcapsules, and continue stirring at this temperature for 10 minutes; heat it to 100°C at a heating rate of 5°C / min, add 12.5 parts of hindered amine stabilizer, and continue stirring at this temperature. 10min; heat up to 120℃ at a heating rate of 4℃ / min, add 75 parts of KH-570, and continue stirring at this temperature for 10min; heat up to 130℃ at a heating rate of 3℃ / min, add 25 parts of 2-hydroxy-4-dodecyloxybenzophenone, and continue stirring at this temperature for 10min; heat up to 140℃ at a heating rate of 2℃ / min, add 15 parts of 2,6-di-tert-butyl-p-cresol, and continue stirring at this temperature for 10min; heat up to 150℃ at a heating rate of 1℃ / min, and mix at this temperature for 17.5min.

[0046] S3. Granulation: Transfer to a twin-screw extruder (Nanjing Yuesheng, L / D=40), extrusion temperature 190° C., extrusion granulation to obtain masterbatch.

[0047] S4. Casting pipe: The masterbatch is extruded through a single-screw extruder. The extruded UPVC pipe has a length-to-diameter ratio of 30:1 and an extrusion temperature of 200°C. The extruded UPVC pipe passes through a vacuum setting box (the vacuum degree of the vacuum setting box is set to -0.08MPa) and finally falls into a cooling water tank for setting and cooling (the cooling water tank is provided with three levels of cooling, and the water temperatures are 30°C, 25°C, and 20°C, respectively).

[0048] Example 2 The difference between this embodiment and embodiment 1 is that the added amount of polystyrene-b-polycaprolactone is changed to 120 parts, and the added amount of sodium sulfate decahydrate microcapsules is changed to 70 parts.

[0049] Example 3 The difference between this embodiment and embodiment 1 is that the added amount of polystyrene-b-polycaprolactone is changed to 130 parts, and the added amount of sodium sulfate decahydrate microcapsules is changed to 60 parts.

[0050] Example 4 The difference between this embodiment and embodiment 1 is that the ratio of Tinuvin 622:Chimassorb 944 in the hindered amine stabilizer is changed from 7:3 to 7:1.

[0051] Example 5 The difference between this embodiment and embodiment 1 is that the ratio of Tinuvin 622:Chimassorb 944 in the hindered amine stabilizer is changed from 7:3 to 7:5.

[0052] Comparative Example Comparative Example 1 This comparative example is different from Example 1 in that the hindered amine stabilizer is changed from 12.5 parts of Tinuvin 622:Chimassorb 944 (7:3) to 12.5 parts of Tinuvin 622.

[0053] Comparative Example 2 This comparative example is different from Example 1 in that the hindered amine stabilizer is changed from 12.5 parts of Tinuvin 622:Chimassorb 944 (7:3) to 12.5 parts of Chimassorb 944.

[0054] Comparative Example 3 This comparative example differs from Example 1 in that 125 parts of polystyrene-b-polycaprolactone are not added and are replaced with an equal amount of sodium sulfate decahydrate microcapsules, namely 190 parts of sodium sulfate decahydrate microcapsules.

[0055] The specific process differences are as follows: Mixing: Start a high-speed mixer at 900 rpm, add 1000 parts of polyvinyl chloride resin to the mixer at room temperature, heat it to 80°C at a heating rate of 3°C / min, add 190 parts of sodium sulfate decahydrate microcapsules, and continue stirring at this temperature for 10 minutes. Other processes are the same as in Example 1.

[0056] Comparative Example 4 This comparative example differs from Example 1 in that 65 parts of sodium sulfate decahydrate microcapsules are not added, and an equal amount of polystyrene-b-polycaprolactone is added, with the amount of polystyrene-b-polycaprolactone being 190 parts.

[0057] The specific process differences are as follows: Mixing: Start the high-speed mixer at 900 rpm, add 1000 parts of polyvinyl chloride resin to the high-speed mixer at room temperature, heat it to 60°C at a heating rate of 5°C / min, add 190 parts of polystyrene-b-polycaprolactone, and continue stirring at this temperature for 10 minutes. Other processes are the same as in Example 1.

[0058] Performance test The thermal resistance of the UPVC pipes prepared in Examples 1-5 and Comparative Examples 1-4 under steady-state conditions was measured according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Insulating Materials - Guarded Hot Plate Method"; the sound pressure level difference between the incident sound and the transmitted sound of the UPVC pipes prepared in Examples 1-5 and Comparative Examples 1-4 was measured according to GB / T 19889.3-2005 "Acoustic Measurement of Sound Insulation of Buildings and Building Elements - Part 3: Measurement of Airborne Sound Insulation of Walls and Floors under Laboratory Conditions" to calculate the weighted sound insulation value (Rw); the flexural strength of the UPVC pipes prepared in Examples 1-5 and Comparative Examples 1-4 was measured according to GB / T 9341-2008 "Determination of Flexural Properties of Plastics"; and the weighted sound insulation value (Rw) of the UPVC pipes prepared in Examples 1-5 and Comparative Examples 1-4 was calculated according to GB / T 16422.2-2022 is "Plastics Laboratory Light Source Exposure Test Method Part 2: Xenon Arc Lamp". UPVC pipes are exposed to strong light for 1000 hours through a xenon arc lamp to simulate the natural light environment. The UPVC pipes are aged and the bending strength of the aged UPVC pipes is tested. The bending strength retention rate is recorded. The test is repeated 5 times and the average value is taken.

[0059] The above test results are recorded in Table 1.

[0060] Table 1 Test data of thermal insulation, sound insulation, bending strength and bending elastic modulus of UPVC pipe Combining the test results of Examples 1-5 and Comparative Examples 1-2, the thermal resistance, weighted sound insulation, flexural strength before aging, and flexural strength after aging of Examples 1-5 are higher than those of Comparative Examples 1-2. This is because the hindered amine stabilizer lacks Tinuvin 622 or Chimassorb 944, resulting in a lack of anchoring or diffusion effect, which causes various performance degradations. This indicates that the hindered amine stabilizer compounded with Tinuvin 622 and Chimassorb 944 forms a dual "anchoring-diffusion" protection, which reduces the yellowing index of the UPVC pipe after UV aging, and also improves the comprehensive performance of the pipe, so that the UPVC pipe has the advantages of heat insulation, sound insulation and aging resistance.

[0061] Combining the test results of Examples 1-5 and Comparative Examples 3-4, the thermal resistance, weighted sound insulation, bending strength before aging, and bending strength after aging of Examples 1-5 are generally higher than those of Comparative Examples 3-4. Due to the lack of polystyrene-b-polycaprolactone or hydrated salt microcapsules, various performance factors are reduced. This shows that the phase change energy storage effect of polystyrene-b-polycaprolactone combined with the hydrated salt microcapsules forms a functional complementarity of "structural thermal insulation-phase change heat absorption", which synergistically improves the thermal insulation, sound insulation and aging resistance of the UPVC pipe.

[0062] This specific embodiment is merely an explanation of the present application and does not limit the present application. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical scope of the present application. The technical scope of the present application is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A UPVC pipe with heat insulation, sound insulation and aging resistance, characterized in that: The invention comprises the following raw materials in parts by weight: 100 parts of polyvinyl chloride resin, 10-15 parts of shape memory polymer, 5-8 parts of hydrated salt microcapsules, 2-3 parts of benzophenone compounds, 1-2 parts of 2,6-di-tert-butyl-p-cresol, 1-1.5 parts of hindered amine stabilizer and 0.5-1 part of silane coupling agent; the hindered amine stabilizer comprises Tinuvin 622, Chimassorb 944 and a compatibilizer, the weight ratio of Tinuvin 622 to Chimassorb 944 is 7:(1-5), the shape memory polymer is polystyrene-b-polycaprolactone, the number average molecular weight of the polystyrene-b-polycaprolactone is 45000-55000 g / mol, the molecular weight of the polystyrene segment accounts for 35-45%, and the molecular weight of the polycaprolactone segment accounts for 55-65%.

2. The heat-insulating, sound-insulating and aging-resistant UPVC pipe according to claim 1 is characterized in that: The weight ratio of Tinuvin 622 to Chimassorb 944 is 7:

3.

3. The heat-insulating, sound-insulating and aging-resistant UPVC pipe according to claim 1 is characterized in that: The compatibilizer is maleic anhydride grafted POE, and the weight ratio of the sum of Tinuvin 622 and Chimassorb 944 to the maleic anhydride grafted POE is (1-2):

1.

4. The heat-insulating, sound-insulating and aging-resistant UPVC pipe according to claim 1, characterized in that: The preparation steps of the hindered amine stabilizer are as follows: Tinuvin 622 and Chimassorb 944 were mixed according to a weight ratio, a compatibilizer was added, and the mixture was mixed in a high shear mixer at 80-100° C. and a rotation speed of 3000-5000 rpm to prepare the hindered amine stabilizer.

5. The heat-insulating, sound-insulating and aging-resistant UPVC pipe according to claim 1 is characterized in that: The benzophenone compound is 2-hydroxy-4-dodecyloxybenzophenone.

6. The heat-insulating, sound-insulating and aging-resistant UPVC pipe according to claim 1, characterized in that: The hydrated salt microcapsules are sodium sulfate decahydrate microcapsules, the average particle size of the microcapsules is 10-30 μm, and the capsule wall material is urea-formaldehyde resin.

7. The heat-insulating, sound-insulating and aging-resistant UPVC pipe according to claim 1, characterized in that: The silane coupling agent is KH-570.

8. A method for preparing the heat-insulating, sound-insulating and aging-resistant UPVC pipe according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Mixing: Add polyvinyl chloride resin to a high-speed mixer at room temperature, heat to 55-65°C, add polystyrene-b-polycaprolactone, heat to 75-85°C, add hydrated salt microcapsules, heat to 95-105°C, add hindered amine stabilizer, heat to 115-125°C, add KH-570, heat to 125-135°C, add benzophenone compounds, heat to 135-145°C, add 2,6-di-tert-butyl-p-cresol, heat to 145-155°C, keep warm, mix and blend, and extrude and granulate to obtain masterbatch; S2: Casting pipe: The masterbatch is extruded through a single screw extruder, and the extruded material is shaped and cooled in a vacuum shaping box and a multi-stage cooling water tank.

9. The method for preparing the heat-insulating, sound-insulating and aging-resistant UPVC pipe according to claim 8, characterized in that: The silane coupling agent needs to be hydrolyzed and activated with an ethanol aqueous solution (volume ratio 1:1) under acidic conditions (pH 4-5) before use.

10. The method for preparing the heat-insulating, sound-insulating and aging-resistant UPVC pipe according to claim 8, characterized in that: In step S1, the mixing speed of the high-speed mixer is 800-1000 rpm, and the heat preservation and mixing time is 15-20 minutes.

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