Preparation method of high-transparency TPE (thermoplastic elastomer) peristaltic pump pipe

Abstract

The invention discloses a preparation method of a high-transparency TPE (thermoplastic elastomer) peristaltic pump pipe, and belongs to the technical field of high-molecular compounds. The preparation method comprises the following steps: blending high cis-1, 4-polybutadiene and polyethylene-polybutadiene to prepare a matrix phase; the method comprises the following steps: carrying out ester exchange reaction on dimethyl carbonate and polypropylene oxide glycol; then adding ethylene glycol as a chain extender to synthesize a polyurethane phase; carrying out melt blending on the two phases at a specific temperature, and adding dicumyl peroxide to initiate selective crosslinking; and finally, carrying out low-temperature and low-pressure extrusion molding to obtain the high-transparency TPE peristaltic pump pipe. By in-situ formation of an interpenetrating polymer network structure, nanoscale microphase separation is realized, so that the prepared pipe has high transparency, excellent fatigue resistance, excellent wear resistance and good chemical resistance at the same time. The method solves the industrial problem that a traditional peristaltic pump pipe is difficult to meet multiple high-performance requirements, and is suitable for the high-added-value fields such as biological pharmacy and precise instruments.

Description

Technical Field

[0001] This invention relates to the field of polymer compound technology, and to a method for preparing a highly transparent TPE thermoplastic peristaltic pump tube. Background Technology

[0002] Peristaltic pumps, as important fluid transfer devices, are widely used in numerous fields such as biopharmaceuticals, medical diagnostics, food and beverage, and chemicals due to their pollution-free, high-precision, and easy-to-clean characteristics. The pump tubing, as a core consumable of the peristaltic pump, directly determines the reliability, transfer accuracy, and service life of the entire pumping system. Currently, common peristaltic pump tubing materials on the market mainly include silicone and ordinary thermoplastic elastomers. However, these traditional materials have significant shortcomings in overall performance, making it difficult to meet the stringent requirements of high-end applications. Firstly, they lack transparency. Many TPE materials suffer from poor compatibility among their components, leading to phase separation or additive migration and precipitation, resulting in low tubing transparency. This severely affects operators' real-time observation and monitoring of the fluid state inside the tubing, failing to meet the high-visibility requirements of applications such as precision filling and cell culture. Secondly, they have poor fatigue and wear resistance. During operation, the pump tubing must continuously withstand repeated squeezing, friction, and recovery deformation from the rollers. Traditional materials are prone to permanent deformation, crack propagation, and accelerated wear under long-term dynamic stress, leading to short pump pipe life, rapid decline in flow accuracy, and potential particle shedding that contaminates the fluid. Thirdly, they have limited chemical stability. Some TPE or silicone pipes swell, age, become brittle, or exhibit increased precipitates when in contact with organic solvents, oils, or certain biochemical reagents. This not only affects the pipe's lifespan but may also contaminate the transported chemicals or pharmaceuticals, posing safety risks. Fourthly, they have poor processing performance. To obtain certain mechanical properties, it is usually necessary to increase the degree of cross-linking or molecular weight of the material, but this often results in high melt viscosity and a narrow processing window. At higher processing temperatures or shear forces, the material is prone to degradation or destruction of the cross-linked structure, which impairs its final performance and increases production difficulty and cost.

[0003] Therefore, developing a novel high-performance TPE peristaltic pump tube manufacturing method that combines high transparency, excellent fatigue resistance, outstanding wear resistance, good chemical stability, and ease of processing has become a pressing technical challenge in this field. This invention aims to overcome the shortcomings of the prior art and provide a solution with superior overall performance. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide a method for preparing a highly transparent TPE thermoplastic peristaltic pump tube, which solves the problems of poor transparency, fatigue resistance, wear resistance, chemical stability and processing performance of peristaltic pump tubes.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a highly transparent TPE thermoplastic peristaltic pump tube, specifically including the following steps: S1: Heat 50-70 parts by weight of high cis-1,4-polybutadiene to make it into a viscous fluid, then continuously stir the fluid, and then add 30-50 parts by weight of polyethylene-polybutadiene to the fluid and stir. S2: Heat 20-40 parts by weight of polypropylene oxide glycol, then dehydrate it for 1 hour under a vacuum of -0.095 MPa. After dehydration is complete, lower the temperature of the polypropylene oxide glycol, add 15-40 parts by weight of dimethyl carbonate, and stir until a homogeneous system is formed under nitrogen protection. S3: Add 5-30 parts by weight of ethylene glycol to the product in step S2, then raise the system temperature, control the ambient vacuum at -0.08MPa, and continue stirring to generate high molecular weight polyurethane. After the reaction is complete, place the fluid in a vacuum environment to remove small molecule dimethyl carbonate and byproduct methanol. S4: Take 50-60 parts by weight of the polybutadiene blend prepared in S1, heat it and stir continuously. Then weigh 40-50 parts by weight of the polyurethane prepared in S3 and 0.5-1.5 parts by weight of dicumyl peroxide, and stir continuously until the torque value stabilizes. S5: The fluid is extruded through a twin-screw extruder to form a tube blank, which is then connected to a vacuum pump to make the tube blank fit tightly against the inner wall. The tube is then immediately placed in an air-cooled sizing jacket to perform preliminary shaping and surface curing. Finally, the tube is placed in a water-cooled jacket to cool and cure.

[0006] Preferably, in S1, high cis-1,4-polybutadiene is heated to 80-100°C to become a viscous fluid, and then stirred at 100 rpm for 1 hour.

[0007] Preferably, in step S2, polypropylene glycol is heated to 120°C to 180°C and dehydrated for 1 hour, then the polypropylene glycol is cooled to 80°C to 110°C and dimethyl carbonate is added, and the mixture is stirred at 200 rpm for 2 hours.

[0008] Preferably, in step S3, before adding ethylene glycol, the system is heated to 150–180°C and stirred continuously for 2 hours.

[0009] Preferably, after the reaction in S3 is completed, the mixture is placed in a vacuum environment of -0.08 MPa.

[0010] Preferably, in step S4, the polybutadiene and polyurethane are heated to 150–180°C and stirred at a speed of 500 rpm.

[0011] Preferably, in step S4, stirring continues until the torque value stabilizes at its peak and then enters a stable state; the stable state refers to the torque value fluctuating within 3 to 5 minutes without exceeding ±5% of the peak torque.

[0012] Preferably, S5 extrudes the tube blank at a pressure of 0.5 to 1.0 MPa.

[0013] Preferably, in step S5, the pipe is quickly placed in an air-cooled sizing sleeve at 65-70°C for initial shaping.

[0014] Preferably, in step S5, after initial shaping, the pipe is placed in a water-cooled jacket at 20-25°C for cooling and solidification.

[0015] The technical effects and advantages of the method for preparing a high-transparency TPE thermoplastic peristaltic pump tube according to the present invention are as follows: 1. In this invention, the polyethylene-polybutadiene block and high cis-1,4-polybutadiene are highly similar in chemical structure, both being nonpolar hydrocarbon chains, thus exhibiting good compatibility. The block has a low molecular weight and soft chain segments, which, after being incorporated, can penetrate between the polybutadiene molecular chains, playing a role in isolation and lubrication, reducing entanglement and friction between polymer chains, thereby lowering melt viscosity and improving fluidity at processing temperatures.

[0016] 2. In this invention, dimethyl carbonate undergoes an ester exchange reaction with hydroxyl-terminated polypropylene glycol to generate a methoxycarbonyl-COOCH3 group. The reaction mechanism is Polyether-OH + (CH3O)2C=O → Polyether-O-COOCH3 + CH3OH.

[0017] 3. In this invention, ethylene glycol is added as a chain extender. Ethylene glycol undergoes an esterification exchange reaction with methoxy carbonyl groups to generate high molecular weight polyurethane. The reaction mechanism is Polyether-O-COOCH3+HO-CH2CH2-OH→Polyether-Urethane+CH3OH.

[0018] 4. In this invention, dimethyl carbonate and ethylene glycol are used to synthesize polyurethane, which is then mixed with polybutadiene. The polyurethane and polybutadiene form physical crosslinking points. After the pipe is cooled to room temperature, the polarity of the polyurethane segments and the hydrogen bonding effect are used to form a nanoscale microphase separation structure, which serves as a physical crosslinking point to enhance and solidify the non-polar polybutadiene soft phase matrix.

[0019] 5. This invention, through physical blending, prepares in-situ IPN structure TPV, fundamentally optimizing the microstructure of the material.

[0020] 6. This invention generates free radicals through the decomposition of diisopropylbenzene peroxide. These free radicals preferentially attack and crosslink the polybutadiene phase, while the polyurethane phase maintains linear thermoplasticity. The ethylene glycol remaining in the prepolymer may also form chemical bridges at the interface between the two phases, thereby forming a unique IPN structure.

[0021] 7. This invention prevents the IPN structure from being damaged by low-temperature, low-pressure extrusion. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the chemical structure of the polyethylene-polybutadiene block copolymer in this invention. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0025] Example 1: This embodiment provides a method for preparing a highly transparent TPE thermoplastic peristaltic pump tube, the specific implementation steps of which include: Experimental materials: Polybutadiene raw materials: 60 parts by weight of high cis-1,4-polybutadiene, 40 parts by weight of polyethylene-polybutadiene; Polyurethane raw materials: 40 parts by weight of polypropylene glycol, 40 parts by weight of dimethyl carbonate, and 20 parts by weight of ethylene glycol; Other raw materials: 0.1 parts by weight of dicumyl peroxide; TPE raw materials: 60 parts by weight of polybutadiene and 40 parts by weight of polyurethane.

[0026] Experimental objective: TPE thermoplastic peristaltic pump tubing was prepared by mixing high cis-1,4-polybutadiene and other substances.

[0027] Experimental steps: S1: Heat high cis-1,4-polybutadiene to 100°C to form a viscous fluid, then stir the fluid at 100 rpm, and then add polyethylene-polybutadiene to the fluid and stir for 1 hour. S2: Dehydrate polyoxypropylene glycol at 120°C and vacuum degree -0.095MPa for 1 hour, then cool the polyoxypropylene glycol to 80°C, add dimethyl carbonate, and stir at 200rpm for 2 hours under nitrogen protection to form a homogeneous system. S3: Add the product from step S2 to ethylene glycol, then raise the temperature of the system to 150°C and continue stirring for 2 hours to generate high molecular weight polyurethane. Finally, after the reaction is complete, place it under a vacuum of -0.08 MPa to remove small molecule dimethyl carbonate and byproduct methanol. S4: Heat the fluid in S1 to 170°C, then stir continuously at 400 rpm, and then add the polyurethane and dicumyl peroxide prepared in S3, and continue stirring until the torque value stabilizes. S5: The fluid is extruded into a tube blank at a low temperature and low pressure of 160°C through a twin-screw extruder. Then, it is connected to a vacuum pump to make the tube blank fit tightly against the inner wall. The tube is then quickly placed in a 70°C air-cooled sizing sleeve to perform preliminary shaping and surface curing. Finally, the tube is placed in a 25°C water-cooled jacket to cool and cure.

[0028] Experimental results: See Table 1 for details.

[0029] Table 1: Test Results of Example 1

[0030] Example 1 demonstrates the best overall performance. The excellent compatibility between high cis-1,4-polybutadiene and polyethylene-polybutadiene, along with the subsequently formed interpenetrating polymer network structure, contributes to the pipe's extremely high fatigue life. The uniformly dispersed polyurethane phase, acting as a hard segment, provides excellent wear resistance. The IPN structure, combined with the non-polarity of polybutadiene and the polarity of polyurethane, results in excellent resistance to acids, alkalis, and ethanol, exhibiting exceptional chemical stability. The superior compatibility among the components and the formation of a nanoscale microphase separation structure are key to achieving ultra-high transparency. This example achieves the optimal balance across all performance aspects.

[0031] Example 2: This embodiment provides a method for preparing a highly transparent TPE thermoplastic peristaltic pump tube, using different proportions of raw materials. The specific implementation steps include: Experimental materials: Polybutadiene raw materials: 50 parts by weight of high cis-1,4-polybutadiene, 50 parts by weight of polyethylene-polybutadiene; Polyurethane raw materials: 30 parts by weight of polypropylene glycol, 40 parts by weight of dimethyl carbonate, and 30 parts by weight of ethylene glycol; Other raw materials: 0.1 parts by weight of dicumyl peroxide; TPE raw materials: 60 parts by weight of polybutadiene and 40 parts by weight of polyurethane.

[0032] Experimental objective: TPE thermoplastic peristaltic pump tubing was prepared by mixing different weight parts of high cis-1,4-polybutadiene and other substances.

[0033] Experimental steps: S1: Heat high cis-1,4-polybutadiene to 100°C to form a viscous fluid, then stir the fluid at 100 rpm, and then add polyethylene-polybutadiene to the fluid and stir for 1 hour. S2: Dehydrate polyoxypropylene glycol at 120°C and vacuum degree -0.095MPa for 1 hour, then cool the polyoxypropylene glycol to 80°C, add dimethyl carbonate, and stir at 200rpm for 2 hours under nitrogen protection to form a homogeneous system. S3: Add the product from step S2 to ethylene glycol, then raise the temperature of the system to 150°C and continue stirring for 2 hours to generate high molecular weight polyurethane. Finally, after the reaction is complete, place it under a vacuum of -0.08 MPa to remove small molecule dimethyl carbonate and byproduct methanol. S4: Heat the fluid in S1 to 170°C, then stir continuously at 400 rpm, and then add the polyurethane and dicumyl peroxide prepared in S3, and continue stirring until the torque value stabilizes. S5: The fluid is extruded into a tube blank at a low temperature and low pressure of 160°C through a twin-screw extruder. Then, it is connected to a vacuum pump to make the tube blank fit tightly against the inner wall. The tube is then quickly placed in a 70°C air-cooled sizing sleeve to perform preliminary shaping and surface curing. Finally, the tube is placed in a 25°C water-cooled jacket to cool and cure.

[0034] Experimental results: See Table 2 for details.

[0035] Table 2: Test Results of Example 2

[0036] Example 2, through formulation adjustments, shifted the performance focus. The increased amount of polyethylene-polybutadiene, acting as a compatibilizer, further promoted two-phase compatibility, maintaining extremely high transparency. The significantly increased amount of ethylene glycol, acting as a chain extender, generated polyurethane with a higher hard segment content, thus imparting superior wear resistance to the pipe. However, the same amount of crosslinking agent was insufficient to effectively crosslink the higher proportion of polybutadiene, resulting in insufficient crosslinking network density and a lower fatigue life compared to Example 1. The increased proportion of polyurethane hard segments also slightly increased its affinity for ethanol, leading to slightly lower ethanol resistance compared to Example 1.

[0037] Example 3: This embodiment provides a method for preparing a highly transparent TPE thermoplastic peristaltic pump tube, which involves changing the temperature at which ethylene glycol is added to the system. The specific implementation steps include: Experimental materials: Polybutadiene raw materials: 60 parts by weight of high cis-1,4-polybutadiene, 40 parts by weight of polyethylene-polybutadiene; Polyurethane raw materials: 40 parts by weight of polypropylene glycol, 40 parts by weight of dimethyl carbonate, and 20 parts by weight of ethylene glycol; Other raw materials: 0.1 parts by weight of dicumyl peroxide; TPE raw materials: 60 parts by weight of polybutadiene and 40 parts by weight of polyurethane.

[0038] Experimental objective: TPE thermoplastic peristaltic pump tubing was prepared by mixing high cis-1,4-polybutadiene and other substances.

[0039] Experimental steps: S1: Heat high cis-1,4-polybutadiene to 100°C to form a viscous fluid, then stir the fluid at 100 rpm, and then add polyethylene-polybutadiene to the fluid and stir for 1 hour. S2: Dehydrate polyoxypropylene glycol at 120°C and vacuum degree -0.095MPa for 1 hour, then cool the polyoxypropylene glycol to 80°C, add dimethyl carbonate, and stir at 200rpm for 2 hours under nitrogen protection to form a homogeneous system. S3: Add the product from step S2 to ethylene glycol, then raise the temperature of the system to 180°C and continue stirring for 2 hours to generate high molecular weight polyurethane. Finally, after the reaction is complete, place it under a vacuum of -0.08MPa to remove small molecule dimethyl carbonate and byproduct methanol. S4: Heat the fluid in S1 to 170°C, then stir continuously at 400 rpm, and then add the polyurethane and dicumyl peroxide prepared in S3, and continue stirring until the torque value stabilizes. S5: The fluid is extruded into a tube blank at a low temperature and low pressure of 160°C through a twin-screw extruder. Then, it is connected to a vacuum pump to make the tube blank fit tightly against the inner wall. The tube is then quickly placed in a 70°C air-cooled sizing sleeve to perform preliminary shaping and surface curing. Finally, the tube is placed in a 25°C water-cooled jacket to cool and cure.

[0040] Experimental results: See Table 3 for details.

[0041] Table 3: Test Results of Example 3

[0042] Increased reaction temperature leads to more side reactions, a wider molecular weight distribution of polyurethane, and some low molecular weight segments acting as plasticizers, while some segments that fail to extend effectively become structural defects, resulting in a decrease in the uniformity and integrity of the overall network structure. Due to the wider molecular weight distribution, the overall consistency of the material deteriorates, and the effectiveness of hard segment microregions may decrease, leading to a reduction in wear resistance. Side reactions may generate more end groups or irregular structures, increasing the material's tendency to swell in solvents, and chemical resistance, especially ethanol resistance, decreases compared to Example 1. Ethanol resistance is the most significantly affected property. Increasing the S3 reaction temperature sacrifices reaction precision; although it may shorten the reaction time, it leads to a comprehensive decline in overall performance, especially a significant reduction in transparency.

[0043] Example 4: This embodiment provides a method for preparing a highly transparent TPE thermoplastic peristaltic pump tube, which increases the reaction temperature of polybutadiene and polyurethane. The specific implementation steps include: Experimental materials: Polybutadiene raw materials: 60 parts by weight of high cis-1,4-polybutadiene, 40 parts by weight of polyethylene-polybutadiene; Polyurethane raw materials: 40 parts by weight of polypropylene glycol, 40 parts by weight of dimethyl carbonate, and 20 parts by weight of ethylene glycol; Other raw materials: 0.1 parts by weight of dicumyl peroxide; TPE raw materials: 60 parts by weight of polybutadiene and 40 parts by weight of polyurethane.

[0044] Experimental objective: TPE thermoplastic peristaltic pump tubing was prepared by mixing high cis-1,4-polybutadiene and other substances.

[0045] Experimental steps: S1: Heat high cis-1,4-polybutadiene to 100°C to form a viscous fluid, then stir the fluid at 100 rpm, and then add polyethylene-polybutadiene to the fluid and stir for 1 hour. S2: Dehydrate polyoxypropylene glycol at 120°C and vacuum degree -0.095MPa for 1 hour, then cool the polyoxypropylene glycol to 80°C, add dimethyl carbonate, and stir at 200rpm for 2 hours under nitrogen protection to form a homogeneous system. S3: Add the product from step S2 to ethylene glycol, then raise the temperature of the system to 150°C and continue stirring for 2 hours to generate high molecular weight polyurethane. Finally, after the reaction is complete, place it under a vacuum of -0.08 MPa to remove small molecule dimethyl carbonate and byproduct methanol. S4: Heat the fluid in S1 to 200°C, then stir continuously at 400 rpm, and then add the polyurethane and dicumyl peroxide prepared in S3, and continue stirring until the torque value stabilizes. S5: The fluid is extruded into a tube blank at a low temperature and low pressure of 160°C through a twin-screw extruder. Then, it is connected to a vacuum pump to make the tube blank fit tightly against the inner wall. The tube is then quickly placed in a 70°C air-cooled sizing sleeve to perform preliminary shaping and surface curing. Finally, the tube is placed in a 25°C water-cooled jacket to cool and cure.

[0046] Experimental results: See Table 4 for details.

[0047] Table 4: Test Results of Example 4

[0048] Performance deteriorates drastically. The excessively high blending temperature of 200℃ causes DCP to decompose and crosslink extensively during the mixing stage, resulting in localized over-crosslinking and insufficient crosslinking in other areas, forming a highly heterogeneous mixture with numerous serious defects and extremely poor fatigue resistance. Due to uneven mixing, the material cannot form a uniform and effective reinforcing phase and crosslinking network, severely reducing wear resistance. The heterogeneous structure contains numerous weak interface regions, making it highly susceptible to solvent penetration and swelling, leading to decreased chemical resistance. Acid and alkali resistance also decreases due to the disruption of the IPN structure. Uneven mixing increases phase separation size, and localized overheating may cause yellowing and degradation of the material, severely reducing transparency; the material may appear milky white or pale yellow. Significantly increasing the S4 blending temperature is a destructive process error. It completely destroys the foundation for forming a uniform IPN structure, leading to a catastrophic decline in all properties, especially mechanical properties and transparency, thus highlighting the crucial importance of low-temperature blending for protecting structure and performance.

[0049] Example 5: This embodiment provides a method for preparing a highly transparent TPE thermoplastic peristaltic pump tube, which increases the extrusion temperature in a twin-screw extruder. The specific implementation steps include: Experimental materials: Polybutadiene raw materials: 60 parts by weight of high cis-1,4-polybutadiene, 40 parts by weight of polyethylene-polybutadiene; Polyurethane raw materials: 40 parts by weight of polypropylene glycol, 40 parts by weight of dimethyl carbonate, and 20 parts by weight of ethylene glycol; Other raw materials: 0.1 parts by weight of dicumyl peroxide; TPE raw materials: 60 parts by weight of polybutadiene and 40 parts by weight of polyurethane.

[0050] Experimental objective: TPE thermoplastic peristaltic pump tubing was prepared by mixing high cis-1,4-polybutadiene and other substances.

[0051] Experimental steps: S1: Heat high cis-1,4-polybutadiene to 100°C to form a viscous fluid, then stir the fluid at 100 rpm, and then add polyethylene-polybutadiene to the fluid and stir for 1 hour. S2: Dehydrate polyoxypropylene glycol at 120°C and vacuum degree -0.095MPa for 1 hour, then cool the polyoxypropylene glycol to 80°C, add dimethyl carbonate, and stir at 200rpm for 2 hours under nitrogen protection to form a homogeneous system. S3: Add the product from step S2 to ethylene glycol, then raise the temperature of the system to 150°C and continue stirring for 2 hours to generate high molecular weight polyurethane. Finally, after the reaction is complete, place it under a vacuum of -0.08 MPa to remove small molecule dimethyl carbonate and byproduct methanol. S4: Heat the fluid in S1 to 170°C, then stir continuously at 400 rpm, and then add the polyurethane and dicumyl peroxide prepared in S3, and continue stirring until the torque value stabilizes. S5: The fluid is extruded into a tube blank at low pressure at 200°C through a twin-screw extruder. Then, it is connected to a vacuum pump to make the tube blank fit tightly against the inner wall. The tube is then quickly placed in a 70°C air-cooled sizing jacket to perform preliminary shaping and surface curing. Finally, the tube is placed in a 25°C water-cooled jacket to cool and cure.

[0052] Experimental results: See Table 5 for details.

[0053] Table 5: Test Results of Example 5

[0054] High-temperature extrusion disrupts the IPN structure and cross-linking points already formed in S4, leading to cross-linking network degradation and molecular chain breakage, thus significantly reducing elastic recovery and durability. Similarly, due to structural damage, the reinforcing effect of the polyurethane phase and the cross-linking network of the polybutadiene phase are weakened, resulting in decreased abrasion resistance. The damaged material structure makes it more susceptible to solvent penetration, and its chemical stability, especially its resistance to polar solvents, deteriorates. High temperatures cause thermal degradation and yellowing of the material, and may cause the already formed nanoscale microstructures to agglomerate and enlarge, inducing light scattering and leading to a significant decrease in transparency. Increasing the extrusion temperature aims to improve processing flowability, but at the cost of sacrificing the final product's performance. This demonstrates that low-temperature, low-pressure extrusion processes are an indispensable and crucial step in protecting the microstructure and properties of the final product.

[0055] Comparative Example 1 This embodiment provides a method for preparing a conventional TPE thermoplastic peristaltic pump tube, and the specific implementation steps include: Experimental materials: 50 parts by weight of SEBS elastomer, 20 parts by weight of polypropylene, 25 parts by weight of naphthenic oil, 2.0 parts by weight of antioxidant 1010, and 3.0 parts by weight of lubricant.

[0056] Experimental objective: A conventional TPE peristaltic pump tube was prepared by simple melt blending using a common SEBS / PP blending modification system, in order to compare its performance differences with the method of the present invention.

[0057] Experimental steps: S1: Mix SEBS elastomer and naphthenic oil at room temperature and stir until the naphthenic oil is fully absorbed by SEBS to obtain a pre-swollen compound; S2: Mix polypropylene granules with antioxidant 1010 and lubricant in a high-speed mixer for 3-5 minutes to ensure uniform dispersion; S3: Add the pre-expanded rubber compound obtained in step S1 and the mixture in step S2 together into the feed port of the twin-screw extruder; S4: Melt blending and extrusion granulation is carried out through a twin-screw extruder. The temperature of each section of the extruder is set to 170℃ in zone 1, 180℃ in zone 2, 190℃ in zone 3, and 195℃ at the die head. The screw speed is 250 rpm. S5: The TPE granules obtained in step S4 are extruded into a tube blank through a single screw extruder at an extrusion temperature of 190-200℃. S6: The extruded tube blank is cooled and shaped in a warm water cooling tank, and then pulled and wound by a traction machine to obtain the final TPE pump tube.

[0058] Experimental results: See Table 6 for details.

[0059] Table 6: Test Results of Comparative Example 1

[0060] This comparative example uses a conventional SEBS / PP / oil blending system. SEBS and PP are only physically blended, resulting in limited compatibility, large phase separation dimensions, and an opaque, milky-white material that fails to meet visualization requirements. The simple physical cross-linking network lacks strength and has poor fatigue resistance, easily failing under repeated extrusion. SEBS itself has generally poor wear resistance and high abrasion rate. The large amount of added naphthenic oil and the unsaturated bonds in SEBS significantly reduce its chemical resistance, especially its resistance to ethanol, leading to easy swelling, precipitation, and fluid contamination. The high-temperature extrusion process also easily causes oil precipitation and material aging. This comparative example vividly illustrates the functional limitations of traditional technologies in high-performance pump tube applications.

[0061] Example 1 uses the optimal raw material ratio and precisely controlled low-temperature process to construct a uniform and stable interpenetrating polymer network (IPN) structure.

[0062] Example 2 employs a strategy of using high compatibilizer and high chain extender dosages, sacrificing some crosslinking network strength in exchange for ultimate transparency and wear resistance, thus achieving customized performance.

[0063] Example 3 demonstrated the high sensitivity of the reaction process to temperature by increasing the polymerization temperature. High temperature led to an increase in side reactions, which disrupted the regularity of the molecular structure and resulted in a comprehensive decline in overall performance.

[0064] Example 4 uses a method of increasing the blending temperature, which causes the crosslinking agent to decompose prematurely, resulting in severe mixing unevenness and structural defects. This, in turn, confirms the importance of low-temperature blending for protecting the IPN structure.

[0065] Example 5 demonstrates the destructive effect of subsequent processing steps on the formed structure by increasing the extrusion temperature. High-temperature extrusion leads to the degradation of the cross-linked network and the aggregation of micro-region structures, resulting in the deterioration of the final product performance.

[0066] Comparative Example 1 uses a traditional simple physical blending system of SEBS / PP / oil, which suffers from severe phase separation, reliance on small molecule plasticizers, and lack of chemical bonding, highlighting the inherent defects of traditional materials in terms of transparency, durability, and chemical resistance.

[0067] Comparing the examples and comparative examples, Example 1 achieved the optimal balance in terms of high transparency, fatigue resistance, abrasion resistance, and chemical stability. It cleverly improved the overall performance of the material by synthesizing polyurethane in situ and forming a nanoscale IPN structure. Although Example 2 showed a slight decrease in fatigue resistance, it achieved even greater transparency and abrasion resistance. Example 3, by increasing the polymerization temperature, shortened the reaction time, but the increased side reactions led to a wider molecular weight distribution, resulting in decreased transparency and deteriorated overall performance, demonstrating the sensitivity of temperature control during the polymerization process. Examples 4 and 5 show that excessively high blending or extrusion temperatures can destroy the formed IPN structure and cross-linking network, leading to a significant decrease in mechanical properties, chemical resistance, and transparency, confirming the crucial role of low-temperature, low-pressure processes in maintaining the material's microstructure and final properties. Comparative Example 1 highlights the functional limitations of traditional physically blended TPE materials in terms of overall performance. Therefore, this invention is not a simple formula adjustment, but rather an innovation in the entire process from molecular structure design to molding process through an innovative in-situ polymerization-physical crosslinking-selective chemical crosslinking synergistic mechanism. It fundamentally solves the industry problem that traditional peristaltic pump tube materials cannot simultaneously meet multiple high-performance requirements, and represents an important direction for technological development in this field.

[0068] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

[0069] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a highly transparent TPE thermoplastic peristaltic pump tube, characterized in that, Specifically, the following steps are included: S1: Heat 50-70 parts by weight of high cis-1,4-polybutadiene to make it into a viscous fluid, then continuously stir the fluid, and then add 30-50 parts by weight of polyethylene-polybutadiene to the fluid and stir. S2: Heat 20-40 parts by weight of polypropylene oxide glycol, then dehydrate it for 1 hour under a vacuum of -0.095 MPa. After dehydration is complete, lower the temperature of the polypropylene oxide glycol, add 15-40 parts by weight of dimethyl carbonate, and stir until a homogeneous system is formed under nitrogen protection. S3: Add 5-30 parts by weight of ethylene glycol to the product from step S2, then raise the system temperature, control the ambient vacuum at -0.08MPa, and continue stirring to generate high molecular weight polyurethane. After the reaction is complete, place the fluid in a vacuum environment to remove small molecule dimethyl carbonate and byproduct methanol. S4: Heat and stir 50-60 parts by weight of the polybutadiene blend prepared in S1. Then weigh 40-50 parts by weight of the polyurethane prepared in S3 and 0.5-1.5 parts by weight of dicumyl peroxide, and stir continuously until the torque value stabilizes. S5: The fluid is extruded through a twin-screw extruder to form a tube blank, which is then connected to a vacuum pump to make the tube blank fit tightly against the inner wall. The tube is then immediately placed in an air-cooled sizing jacket to perform preliminary shaping and surface curing. Finally, the tube is placed in a water-cooled jacket to cool and cure.

2. The method for preparing a high-transparency TPE thermoplastic peristaltic pump tube as described in claim 1, characterized in that, In S1, high cis-1,4-polybutadiene is heated to 80-100°C to become a viscous fluid, and then stirred at 100 rpm for 1 hour.

3. The method for preparing a high-transparency TPE thermoplastic peristaltic pump tube as described in claim 1, characterized in that, In S2, polypropylene glycol is heated to 120°C–180°C and dehydrated for 1 hour. Then, the polypropylene glycol is cooled to 80°C–110°C and dimethyl carbonate is added. The mixture is stirred at 200 rpm for 2 hours.

4. The method for preparing a high-transparency TPE thermoplastic peristaltic pump tube as described in claim 1, characterized in that, Before adding ethylene glycol in S3, the system is heated to 150–180°C and stirred continuously for 2 hours.

5. The method for preparing a high-transparency TPE thermoplastic peristaltic pump tube as described in claim 1, characterized in that, After the reaction in S3 is complete, it is placed in a vacuum environment of -0.08 MPa.

6. The method for preparing a high-transparency TPE thermoplastic peristaltic pump tube as described in claim 1, characterized in that, In S4, polybutadiene and polyurethane are heated to 150–180°C and stirred at 500 rpm.

7. The method for preparing a high-transparency TPE thermoplastic peristaltic pump tube as described in claim 1, characterized in that, Continue stirring in S4 until the torque value stabilizes at its peak and enters a stable state; the stable state means that the torque value fluctuates within 3 to 5 minutes without exceeding ±5% of the peak torque.

8. The method for preparing a high-transparency TPE thermoplastic peristaltic pump tube as described in claim 1, characterized in that, S5 extrudes tube blanks at a pressure of 0.5 to 1.0 MPa.

9. The method for preparing a high-transparency TPE thermoplastic peristaltic pump tube as described in claim 1, characterized in that, In S5, the pipe is quickly placed in an air-cooled sizing sleeve at 65-70℃ for initial shaping.

10. The method for preparing a high-transparency TPE thermoplastic peristaltic pump tube as described in claim 1, characterized in that, After initial shaping in S5, the pipe is placed in a water-cooled jacket at 20-25°C to cool and solidify.

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