A high-voltage-resistant polypropylene composition, a method for preparing the same and use thereof
By combining homopolymer polypropylene of a specific molecular weight with poly1-butene to form an entangled structure, the problem of polypropylene material being prone to cracking under high pressure is solved, and the water pressure resistance of the material is improved, especially its performance in low-temperature environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI KINGFA SCI & TECH
- Filing Date
- 2024-12-31
- Publication Date
- 2026-06-30
AI Technical Summary
Existing polypropylene materials are prone to cracking under high pressure, especially in low-temperature environments where they have poor water pressure resistance. Furthermore, the addition of mineral fillers makes the material brittle and reduces the strength of weld lines, which cannot meet the application requirements of thin-walled sealing parts such as filter bottles.
By combining homopolymer polypropylene with a specific molecular weight and poly-1-butene with a specific melt flow rate, and by controlling the mass ratio of the two, a uniformly dispersed entangled structure is formed, which improves the dispersibility of mineral fillers in polypropylene resin and enhances the high strength and high toughness of the material.
The polypropylene composition exhibits excellent water pressure resistance at both room temperature and low temperature, meeting the high-pressure application requirements of thin-walled sealing parts such as filter bottles.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer composition technology, and more particularly to a high-pressure-resistant polypropylene composition, its preparation method, and its application. Background Technology
[0002] Polypropylene (PP) is widely used in the water purifier industry due to its low density, good hydrophobicity, and high food safety. However, pure PP suffers from insufficient rigidity and strength, as well as defects such as high shrinkage, dimensional instability, and easy crystallization, making it difficult to meet the application requirements of thin-walled sealing parts subjected to long-term water pressure. For example, filter bottles made primarily of PP often rupture under high pressure, leading to leakage. Especially in low-temperature environments, the water inside the filter bottle easily freezes, causing a sharp increase in internal pressure and resulting in cracking. Existing technologies mainly improve the water pressure resistance of PP through mineral filling or glass fiber reinforcement to reduce the risk of filter bottle rupture. However, in practical applications, it has been found that while these conventional modification methods can improve the water pressure resistance of PP at room temperature, the addition of inorganic fillers makes the PP composite material brittle and reduces the weld line strength, resulting in poor water pressure resistance at low temperatures and failing to meet the application requirements of filter bottles in low-temperature environments. Summary of the Invention
[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high pressure-resistant polypropylene composition, its preparation method, and its application.
[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0005] In a first aspect, the present invention provides a high pressure-resistant polypropylene composition, comprising the following components by weight: 20-70 parts of homopolymer polypropylene, 5-20 parts of poly-1-butene, and 0-30 parts of mineral filler.
[0006] The homopolymer polypropylene has a weight-average molecular weight ≥ 300,000 and a molecular weight distribution coefficient of 3 to 5.
[0007] The poly-1-butene conforms to GB / T3682.1-2018 standard, and its melt mass flow rate at 190℃ and 2.16kg is ≤22g / 10min.
[0008] This invention uses homopolymer polypropylene of a specific molecular weight as the matrix resin, combined with poly(1-butene) of a specific melt flow rate, and controls the mass ratio of the two within a suitable range. By utilizing the entanglement of the molecular chains of homopolymer polypropylene and poly(1-butene) with different molecular chain lengths, a large number of uniformly dispersed entangled structures are formed. These entangled structures endow the polypropylene composition with excellent high strength and high toughness, enabling it to withstand high pressure during bursting and tensile processes while exhibiting good resistance to deformation recovery. Poly(1-butene) can also improve the dispersion uniformity of mineral fillers in polypropylene resin, thereby enabling water purifier filter bottles made from this polypropylene composition to have excellent water pressure resistance at both room temperature and low temperature.
[0009] Optionally, the mass fraction of homopolymer polypropylene in the above-mentioned high pressure resistant polypropylene composition is ≥25%, preferably ≥50%; wherein, the specific weight parts of homopolymer polypropylene can be 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, or 65 parts, the specific weight parts of poly1-butene can be 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, or 18 parts, and the specific weight parts of mineral filler can be 5 parts, 10 parts, 15 parts, 20 parts, or 25 parts.
[0010] In addition, the molecular weight distribution coefficient = weight average molecular weight (Mw) / number average molecular weight (Mn), where the weight average molecular weight and number average molecular weight of homopolymer polypropylene can be measured by gel permeation chromatography (GPC).
[0011] As a preferred embodiment of the high pressure-resistant polypropylene composition of the present invention, the high pressure-resistant polypropylene composition comprises the following components in parts by weight: 30-60 parts of homopolymer polypropylene, 8-17 parts of poly-1-butene, and 10-20 parts of mineral filler.
[0012] In a preferred embodiment of the high-pressure-resistant polypropylene composition of the present invention, the weight-average molecular weight of the homopolymer polypropylene is 350,000 to 600,000. Optionally, the weight-average molecular weight of the homopolymer polypropylene can specifically be 350,000, 400,000, 450,000, 500,000, 550,000, or 600,000.
[0013] In a preferred embodiment of the high-pressure-resistant polypropylene composition of the present invention, the poly-1-butene conforms to GB / T3682.1-2018 standard, and its melt flow rate at 190°C and 2.16 kg is 0.3–20 g / 10 min. Optionally, the melt flow rate of the poly-1-butene can specifically be 0.1 g / 10 min, 0.3 g / 10 min, 0.5 g / 10 min, 1 g / 10 min, 3 g / 10 min, 5 g / 10 min, 8 g / 10 min, 12 g / 10 min, 15 g / 10 min, 17 g / 10 min, 19 g / 10 min, or 21 g / 10 min.
[0014] In a preferred embodiment of the high-pressure-resistant polypropylene composition of the present invention, the poly-1-butene has a crystallinity of 50% to 60%. Optionally, the crystallinity of the poly-1-butene can specifically be 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, or 60%. Studies have found that poly-1-butene within this crystallinity range is more conducive to the formation of uniformly dispersed crystals in the polypropylene composition by its crystalline portion, while the amorphous portion becomes entangled with the molecular chains of the homopolymer polypropylene, thereby better dispersing external stress and improving the pressure resistance of the polypropylene composition.
[0015] The crystallinity of poly-1-butene can be determined by DSC. The specific method involves heating a 5 mg poly-1-butene sample to 200 °C under nitrogen protection at a heating rate of 10 °C / min, holding it at that temperature for 5 min, then cooling it to 30 °C at a cooling rate of 10 °C / min and holding it at that temperature for 5 min. Finally, the sample is heated back to 200 °C at a heating rate of 10 °C / min. The enthalpy of fusion ΔH during the second heating process can be obtained. f Crystallinity = ΔH f / ΔH0×100%; where ΔH0 is the melting enthalpy of the polymer when the crystallinity is 100%.
[0016] In a preferred embodiment of the high-pressure-resistant polypropylene composition of the present invention, the density of the poly-1-butene is 0.85–0.95 g / cm³. 3 Preferably, it is 0.91–0.92 g / cm³. 3 Optionally, the density of the poly-1-butene can specifically be 0.85 g / cm³. 3 0.87g / cm 3 0.89g / cm 3 0.91g / cm 3 0.92g / cm 3 0.95g / cm 3 .
[0017] In a preferred embodiment of the high-pressure-resistant polypropylene composition of the present invention, the mineral filler includes at least one selected from talc, calcium carbonate, and barium sulfate. Preferably, the mineral filler is composed of calcium carbonate and talc in a mass ratio of (0.5-1.5):(0.5-1.5).
[0018] In a preferred embodiment of the high-pressure-resistant polypropylene composition of the present invention, the high-pressure-resistant polypropylene composition further includes 0.1 to 1 part by weight of an antioxidant and 0.1 to 1 part by weight of a lubricant. Optionally, the antioxidant may specifically be antioxidant 1010, antioxidant 168, etc., and the lubricant may specifically be erucamide, etc. Furthermore, without affecting the effect of the present invention, colorants, antistatic agents, and other additives may be added to the high-pressure-resistant polypropylene composition as needed.
[0019] Secondly, the present invention provides a method for preparing the above-mentioned high pressure resistant polypropylene composition, comprising the following steps: mixing each component evenly and then melt-extruding to obtain the high pressure resistant polypropylene composition.
[0020] Specifically, in the above preparation method, a twin-screw extruder can be used for melt extrusion, and the melt extrusion temperature is 190-210℃.
[0021] Thirdly, the present invention provides the application of the above-mentioned high pressure-resistant polypropylene composition in the preparation of thin-walled sealed containers.
[0022] Fourthly, the present invention provides a filter bottle for a water purifier, wherein the bottle wall is mainly made of the above-mentioned high pressure resistant polypropylene composition.
[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0024] This invention uses homopolymer polypropylene of a specific molecular weight as the matrix resin, combined with poly(1-butene) of a specific melt flow rate, and controls the mass ratio of the two within a suitable range. By utilizing the entanglement of the molecular chains of homopolymer polypropylene and poly(1-butene) with different molecular chain lengths, a large number of uniformly dispersed entangled structures are formed. These entangled structures endow the polypropylene composition with excellent high strength and high toughness, enabling it to withstand high pressure during bursting and stretching while having good resistance to deformation recovery. Poly(1-butene) can also improve the dispersion uniformity of mineral fillers in homopolymer polypropylene resin, thereby enabling water purifier filter bottles made from this polypropylene composition to have excellent water pressure resistance at both room temperature and low temperature. Detailed Implementation
[0025] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.
[0026] Unless otherwise specified, all other materials, reagents, etc. used in the examples and comparative examples are commercially available.
[0027] 1. Raw materials and reagents
[0028] Homopolymer polypropylene-1, manufactured by Ningbo Jinfeng, has a weight-average molecular weight of 600,000 and a molecular weight distribution coefficient (Mw / Mn) of 4.5.
[0029] Homopolymer polypropylene-2, manufactured by Ningbo Jinfeng, has a weight-average molecular weight of 350,000 and a molecular weight distribution coefficient (Mw / Mn) of 4.0.
[0030] Homopolymer polypropylene-3, manufactured by Ningbo Jinfeng, has a weight-average molecular weight of 250,000 and a molecular weight distribution coefficient (Mw / Mn) of 6.0.
[0031] Copolymer polypropylene, manufactured by Ningbo Jinfeng, has a weight-average molecular weight of 450,000 and a molecular weight distribution coefficient (Mw / Mn) of 4.1.
[0032] Polybutene-1, grade Polybutene-1PB 0110M, manufacturer Basel, melt flow rate is 0.4 g / 10 min, crystallinity is 57%;
[0033] Polybutene-2, grade Polybutene-1DP 8220M, manufacturer Basel, melt flow rate of 2.5 g / 10 min, crystallinity of 56%;
[0034] Polybutene-3, grade Polybutene-1DP 8310M, manufacturer Basel, melt flow rate 3.5 g / 10 min, crystallinity 57%;
[0035] Polybutene-4, grade Polybutene-1PB 0300M, manufacturer Basel, melt flow rate 4 g / 10 min, crystallinity 55%;
[0036] Polybutene-5, grade Polybutene-1DP 0400M, manufacturer Basel, melt flow rate of 15 g / 10 min, crystallinity of 60%;
[0037] Poly(1-butene-6), grade Akoalit PB 4237GREY, manufacturer Basel, melt flow rate 0.4 g / 10 min, crystallinity 63%;
[0038] Polybutene-7, grade Polybutene-1PB 0800M, manufacturer Basel, melt flow rate of 200 g / 10 min, crystallinity of 45%;
[0039] LDPE, grade LDPE 2426, manufacturer: CNOOC Shell;
[0040] The compound mineral powder is obtained by mixing calcium carbonate (brand name HX1500, manufacturer: Guangyuan Chemical) and talc (brand name HS-518, manufacturer: Guangyuan Chemical) in a mass ratio of 1:1.
[0041] The antioxidant is obtained by compounding antioxidant 1010 and antioxidant 168 in a mass ratio of 1:2, wherein both antioxidant 1010 and antioxidant 168 are commercially available.
[0042] The lubricant is erucamide, which is commercially available.
[0043] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the above homopolymer polypropylene or copolymer polypropylene were determined by gel permeation chromatography (GPC).
[0044] The melt mass flow rate of poly-1-butene was measured according to GB / T3682.1-2018 standard at 190℃ and 2.16 kg.
[0045] The crystallinity of poly-1-butene can be determined by DSC. The specific method involves heating a 5 mg poly-1-butene sample to 200 °C under nitrogen protection at a heating rate of 10 °C / min, holding it at that temperature for 5 min, then cooling it to 30 °C at a cooling rate of 10 °C / min and holding it at that temperature for 5 min. Finally, the sample is heated back to 200 °C at a heating rate of 10 °C / min. The enthalpy of fusion ΔH during the second heating process can be obtained. f Crystallinity = ΔH f / ΔH0×100%; where ΔH0 is the melting enthalpy of the polymer when the crystallinity is 100%.
[0046] 2. Examples 1-13 and Comparative Examples 1-5
[0047] Table 1 shows the weight parts of each component in the high-pressure resistant polypropylene compositions of Examples 1-13.
[0048]
[0049] The method for preparing the above-mentioned high-pressure-resistant polypropylene composition includes the following steps:
[0050] According to the formula, each component is added to a high-speed mixer and mixed evenly (mixing speed is 600-1200 r / min, mixing time is 3-5 min). The resulting mixture is then added to a twin-screw extruder for melt extrusion to obtain a high-pressure resistant polypropylene composition. The twin-screw extruder has an aspect ratio of 48:1, and the temperatures of zones one to eight are set to 190℃, 190℃, 195℃, 205℃, 210℃, 215℃, 210℃, and 205℃, respectively.
[0051] Table 2 shows the weight parts of each component in the high-pressure-resistant polypropylene compositions of Comparative Examples 1–5.
[0052] Comparative Example 1 2 3 4 5 Homopolymer Polypropylene-1 / 45 45 45 20 Homopolymer Polypropylene-3 45 / / / / Poly-1-butene-1 12 / / / 37 Poly-1-butene-7 / 12 / / / LDPE / / 12 / / Copolymer polypropylene / / / 12 / Compound mineral powder 15 15 15 15 15 antioxidants 0.5 0.5 0.5 0.5 0.5 lubricant 0.5 0.5 0.5 0.5 0.5
[0053] The method for preparing the above-mentioned high-pressure-resistant polypropylene composition includes the following steps:
[0054] According to the formula, each component is added to a high-speed mixer and mixed evenly (mixing speed is 600-1200 r / min, mixing time is 3-5 min). The resulting mixture is then added to a twin-screw extruder for melt extrusion to obtain a high-pressure resistant polypropylene composition. The twin-screw extruder has an aspect ratio of 48:1, and the temperatures of zones one to eight are set to 190℃, 190℃, 195℃, 205℃, 210℃, 215℃, 210℃, and 205℃, respectively.
[0055] 3. Performance Testing
[0056] 1) Room temperature pressure resistance test: After injection molding of ISO527-2 standard tensile specimens and equilibrating them for 48 hours at 23℃ and 50%RH, they are stretched at a speed of 100mm / min to obtain the stress-strain curve of the product. The vertical axis (y-axis) of the curve is MPa, and the horizontal axis (x-axis) is %. The projected area of the stress-strain curve from the starting point of the tension to the yield point (the slope of the stress-strain curve is 0) in the x-axis direction is calculated as S1. This index is used to evaluate the room temperature pressure resistance performance of the product; the larger the S1, the better the room temperature pressure resistance performance of the product.
[0057] 2) Low-temperature pressure resistance test: Injection-molded ISO527-2 standard tensile specimens were equilibrated at 23℃ and 50% RH for 48 hours, then placed in a -5℃ environment for 24 hours. After removal, the specimens were subjected to a pressure test at 100 mm / min.
[0058] The product is stretched at a certain speed to obtain its stress-strain curve. The vertical axis (y-axis) of the curve is MPa, and the horizontal axis (x-axis) is %. The projected area S2 of the stress-strain curve from the starting point of stretching to the yield point (the slope of the stress-strain curve is 0) in the x-axis direction is calculated. This index is used to evaluate the product's low-temperature pressure resistance performance; the larger the S2, the better the product's low-temperature pressure resistance performance.
[0059] Table 3. Performance of the high-pressure-resistant polypropylene compositions in each example and comparative example.
[0060]
[0061] According to the data in Table 3, the room temperature (23°C) pressure resistance of the high pressure-resistant polypropylene compositions in Examples 1 to 13 is greater than or equal to 224, and the low temperature (-5°C) pressure resistance is above 220. This indicates that the high pressure-resistant polypropylene compositions of the present invention have both excellent room temperature pressure resistance and low temperature pressure resistance, and thus have good pressure resistance stability.
[0062] Furthermore, as shown in Comparative Examples 1 and 2, when the weight-average molecular weight of homopolymer polypropylene is too low and the molecular weight distribution coefficient is too high, or when the melt mass flow rate of poly-1-butene is too high, the degree of molecular chain entanglement between homopolymer polypropylene and poly-1-butene will decrease, making it difficult to effectively improve the room temperature and low temperature pressure resistance of the polypropylene composition. As shown in Comparative Example 3, replacing poly-1-butene with low-density polyethylene (LDPE) in combination with homopolymer polypropylene cannot effectively improve the pressure resistance of the polypropylene composition. As shown in Comparative Example 4, replacing homopolymer polypropylene with poly-1-butene in combination with polypropylene cannot improve the room temperature and low temperature pressure resistance of the polypropylene composition. As shown in Comparative Example 5, the mass ratio of homopolymer polypropylene to poly-1-butene also has an important influence on the pressure resistance of the polypropylene composition. When the mass ratio of homopolymer polypropylene to poly-1-butene is less than 1, it is not conducive to improving the pressure resistance of the polypropylene composition.
[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A high-pressure-resistant polypropylene composition, characterized in that, By weight, it includes the following components: Homopolymer polypropylene 20-70 parts, poly-1-butene 5-20 parts, mineral filler 0-30 parts; The homopolymer polypropylene has a weight-average molecular weight ≥ 300,000 and a component distribution coefficient of 3 to 5. The poly-1-butene conforms to GB / T3682.1-2018 standard, and its melt mass flow rate at 190℃ and 2.16kg is ≤22g / 10min.
2. The high-pressure-resistant polypropylene composition according to claim 1, characterized in that, By weight, it includes the following components: 30-60 parts homopolymer polypropylene, 8-17 parts poly-1-butene, and 10-20 parts mineral filler.
3. The high-pressure-resistant polypropylene composition according to claim 1, characterized in that, The homopolymer polypropylene has a weight-average molecular weight of 350,000 to 600,000.
4. The high-pressure-resistant polypropylene composition according to claim 1, characterized in that, The poly-1-butene conforms to GB / T3682.1-2018 standard, and its melt flow rate at 190℃ and 2.16kg is 0.3~20g / 10min.
5. The high-pressure-resistant polypropylene composition according to claim 1, characterized in that, The crystallinity of the poly-1-butene is 50% to 60%.
6. The high-pressure-resistant polypropylene composition according to claim 1, characterized in that, The mineral filler includes at least one of talc, calcium carbonate, and barium sulfate.
7. The high-pressure-resistant polypropylene composition according to claim 1, characterized in that, The high pressure-resistant polypropylene composition further includes 0.1 to 1 part by weight of an antioxidant and 0.1 to 1 part by weight of a lubricant.
8. A method for preparing the high-pressure-resistant polypropylene composition according to any one of claims 1 to 7, characterized in that, The process includes the following steps: after mixing the components evenly, the mixture is melt-extruded to obtain a high-pressure-resistant polypropylene composition.
9. The use of the high pressure-resistant polypropylene composition according to any one of claims 1 to 7 in the preparation of thin-walled sealing containers.
10. A filter bottle for a water purifier, characterized in that, The filter bottle wall is mainly made of the high pressure-resistant polypropylene composition according to any one of claims 1 to 7.