Polypropylene material with high impact resistance and low melting point, and preparation method and application thereof

Abstract

The application relates to a polypropylene material with high impact resistance and low melting point, a preparation method and application thereof. The polypropylene material with high impact resistance and low melting point comprises the following components in percentage by weight: 99.70-99.99% of polypropylene resin; 0.005-0.15% of nucleating agent A; and 0.005-0.16% of nucleating agent B. The nucleating agent A is a cyclohexane dicarboxylic acid metal salt; and the nucleating agent B is an alkali carbonate. The specific nucleating agent A and the nucleating agent B are compounded, the influence of the melt index fluctuation is overcome, the toughness difference between batch products is reduced, the product performance is stabilized, the polypropylene pipe material with high impact resistance, low melting point and stable quality is provided, the production cost is low, the preparation method is simple, and the large-scale application is facilitated.

Description

Technical Field

[0001] This invention relates to the field of polypropylene, and more specifically, to a polypropylene material with high impact resistance and low melting point, its preparation method, and its application. Background Technology

[0002] As is well known, polypropylene (PP) is widely used in packaging and building pipe applications due to its lightweight, low cost, excellent mechanical properties, and good processing performance. Especially in the building pipe sector, PPR pipe, also known as type III copolymer polypropylene pipe, is made from random copolymer polypropylene through extrusion molding. PPR boasts advantages such as being hygienic and non-toxic, corrosion-resistant, non-scaling, lightweight, easy to install, and having a long service life. With the increasing market demand from the construction, municipal engineering, water conservancy, agriculture, and industry sectors, China's PPR pipe industry has experienced rapid development. However, currently, the production process of PPR pipes is affected by fluctuations in the melt flow index, which significantly impacts the raw material's impact resistance and melting point, resulting in unstable product quality and affecting customer experience. Therefore, stabilizing the quality of PPR pipes is a major direction for future research.

[0003] In the industrial production of polypropylene pipe materials, melt flow index (MFI) is a crucial indicator. Generally, (assuming a fixed ethylene content), as the MFI increases, the flexural modulus of polypropylene increases, meaning both rigidity and melting point improve. However, the impact strength decreases, resulting in reduced toughness. In industrial pipe production, the MFI range is typically set between 0.25 and 0.35 g / 10 min. However, even with precise equipment control, deviations or fluctuations in the MFI between different batches are inevitable. This leads to variations in impact strength and melting point, resulting in significant quality differences between batches of polypropylene pipe raw materials and impacting downstream user acceptance. While there are numerous patents and publications both domestically and internationally on improving the impact performance of polypropylene, most focus on proportionally increasing the product's inherent properties. Research on the impact performance and melting point instability caused by MFI fluctuations, and consequently affecting product quality, is limited. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, this invention proposes a polypropylene material with high impact resistance and a low melting point. Specifically, it relates to a polypropylene material with high impact resistance and a low melting point, its preparation method, and its applications. The purpose of this invention is to overcome the technical problem of unstable impact performance and melting point of pipe materials caused by melt index fluctuations, and to provide a polypropylene pipe material with stable quality, high impact resistance, and a low melting point.

[0005] One objective of this invention is to provide a high-impact, low-melting-point polypropylene material, which may comprise the following components in a blended percentage by weight:

[0006] Polypropylene resin 99.70%–99.99%;

[0007] Nucleating agent A: 0.005%–0.15%;

[0008] Nucleating agent B: 0.005%–0.16%;

[0009] Specifically,

[0010] The polypropylene material used may be in the following amounts: 99.70%, 99.72%, 99.74%, 99.76%, 99.78%, 99.80%, 99.82%, 99.84%, 99.86%, 99.88%, 99.89%, 99.90%, 99.92%, 99.94%, 99.96%, 99.98%, 99.99%, or any value between the above values, or a range between any two of the above values.

[0011] The nucleating agent A can be used in amounts of 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.010%, 0.011%, 0.012%, 0.013%, 0.014%, 0.015%, 0.020%, 0.030%, 0.035%, 0.040%, 0.050%, 0.060%, 0.070%, 0.080%, 0.090%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, or any value between the above values, or a range between any two of the above values.

[0012] The nucleating agent B can be used in amounts of 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.010%, 0.011%, 0.012%, 0.013%, 0.014%, 0.015%, 0.020%, 0.030%, 0.035%, 0.040%, 0.050%, 0.060%, 0.070%, 0.080%, 0.090%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, or any value between the above values, or a range between any two of the above values.

[0013] For example, specifically, the high-impact, low-melting-point polypropylene material may contain the following components by weight percentage:

[0014] Polypropylene resin content: 99.76%–99.94%; preferably 99.82%–99.92%.

[0015] Nucleating agent A: 0.03%–0.11%; preferably 0.03%–0.08%;

[0016] Nucleating agent B: 0.03%–0.13%; preferably 0.05%–0.10%.

[0017] The melt flow index of the polypropylene resin base can be 0.2 to 0.4 g / 10 min (test conditions 230℃, 2.16 kg), preferably 0.25 to 0.35 g / 10 min (test conditions 230℃, 2.16 kg).

[0018] The polypropylene is preferably random copolymer polypropylene.

[0019] The comonomer of the random copolymer polypropylene can be ethylene; the mass content of repeating units of ethylene monomer can be 3.0% to 4.5%, preferably 3.4% to 3.6%; the molecular weight distribution is wide, specifically 4 to 7, preferably 5 to 6, for example Mw / Mn = 5.3 to 5.9.

[0020] The nucleating agent A can be a metal salt of cyclohexanedicarboxylate, or sodium salt of (1R,2S)-rel-1,2-cyclohexanedicarboxylate; specifically, it can be selected from at least one of sodium salt of (1R,2S)-rel-1,2-cyclohexanedicarboxylate, sodium salt of trans-1,4-cyclohexanedicarboxylate, and sodium salt of 1,3-cyclohexanedicarboxylate, preferably sodium salt of (1R,2S)-rel-1,2-cyclohexanedicarboxylate.

[0021] The nucleating agent B can be a basic carbonate, specifically at least one of basic magnesium carbonate, basic calcium carbonate, and basic magnesium calcium carbonate; preferably, it is basic magnesium calcium carbonate.

[0022] A second objective of this invention is to provide a pipe material that may contain the polypropylene material with high impact resistance and low melting point described in one objective of this invention.

[0023] The third objective of this invention is to provide a method for preparing the aforementioned polypropylene material with high impact resistance and low melting point, which may include the following steps:

[0024] The components, including polypropylene, nucleating agent A, and nucleating agent B, are mixed evenly and then melt-blended to obtain the final product. Specifically, the preparation method may include the following steps:

[0025] (1) Weigh and prepare the components according to the mass ratio;

[0026] (2) Place the polypropylene, nucleating agent A and nucleating agent B into a high-speed mixer and mix for 1-5 minutes.

[0027] (3) The above-mentioned uniformly mixed raw materials are added into the twin-screw extruder through the main feed port, and after melt extrusion, stranding, cooling and granulation, the material is dried to prepare polypropylene pipe material with high impact resistance and low melting point. The speed of the extruder screw is 100-600 r / min, and the temperature of the extruder from feeding to the die head is set as follows: 190℃-200℃, 195℃-205℃, 200℃-210℃, 205℃-215℃, 205-215℃, 200℃-210℃, 195℃-205℃, 190℃-200℃, 185℃-195℃.

[0028] The fourth objective of this invention is to provide a pipe material prepared by the preparation method described in the third objective of this invention.

[0029] The fifth objective of this invention is to provide applications for the aforementioned polypropylene material with high impact resistance and low melting point, preferably in the field of home decoration building materials and pipes, specifically for applications such as hot and cold water transmission pipes.

[0030] Polypropylene resin substrates are highly sensitive to the type and dosage of nucleating agents. This invention uses specific types and dosages of nucleating agent A and nucleating agent B in a compound formulation, which produces a synergistic effect. This overcomes the influence of melt index fluctuations, reduces toughness differences between batches of products, and stabilizes the toughness of the pipe material. It can control the toughness of different batches of raw materials within a small range of variation, stabilizing product performance and providing polypropylene pipe materials with stable quality, high impact resistance, and low melting point. Furthermore, it has low production costs, a simple preparation method, and is suitable for large-scale applications. Detailed Implementation

[0031] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0032] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0033] Source of raw materials

[0034] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0035] Polypropylene resin: Random copolymer polypropylene resin base material, which is random copolymer polypropylene produced by Sinopec Tianjin Branch, with the trade name PPR-EH00. The comonomer can be ethylene; the mass content of ethylene monomer repeating units is 3.0% to 4.5%, its melt flow rate is 0.25-0.35 g / 10 min (test conditions: 230℃, 2.16 kg), and the molecular weight distribution is about 5.3-5.9.

[0036] Nucleating agent A: (1R,2S)-rel-1,2-cyclohexanedicarboxylate sodium salt, HPN-715 from Shanghai Milliken Company;

[0037] Nucleating agent B: Basic magnesium calcium carbonate, Shanghai Milliken Company, HPN-M1128;

[0038] β-nucleating agent: Shanxi Chemical Research Institute Co., Ltd., TMB-5;

[0039] POE: ExxonMobil, 9071;

[0040] Calcium carbonate: Heilongjiang Xinda Mining;

[0041] Magnesium carbonate: Wuxi Honglixin New Material Technology Co., Ltd.

[0042] Examples 1-18 and Comparative Examples 1-21

[0043] Three different batches of polypropylene resin base material were taken, and their melt flow index (MFR) were 0.25 g / 10 min, 0.30 g / 10 min, and 0.35 g / 10 min, respectively (test conditions: 230℃, 2.16 kg).

[0044] Weigh the raw materials according to the proportions in ingredient lists 1-3. Place the polypropylene and nucleating agent components in a high-speed mixer and mix for 1-5 minutes. Add the uniformly mixed raw materials from the main feed port into a twin-screw extruder. After melt extrusion, stranding, cooling, and granulation, dry the material to produce a high-impact, low-melting-point polypropylene pipe material. The screw speed of the extruder is 100-600 r / min. The temperature of the extruder from feeding to the die head can be set as follows: 190℃-200℃, 195℃-205℃, 200℃-210℃, 205℃-215℃, 205-215℃, 200℃-210℃, 195℃-205℃, 190℃-200℃, 185℃-195℃.

[0045] The present invention will now be described in detail with reference to specific examples. Unless otherwise specified, the amounts of each component in the examples are by mass percentage.

[0046] The content of each component in the embodiments and comparative examples of the present invention is shown in Tables 1 to 3.

[0047] The products prepared in the examples and comparative examples were subjected to performance tests, and the test results are shown in Tables 4 to 6. Among them, the basic mechanical properties were tested as follows: flexural modulus was tested according to national standard GB / T 9341-2008; notched impact strength of simply supported beams was tested according to national standard GB / T 1043.1-2008; melting temperature (°C) was tested according to the DSC method.

[0048]

[0049]

[0050]

[0051]

[0052] Analysis of the test data results of Comparative Examples 1-3 in Table 5 shows that, before the addition of the additives, the impact strength of the PPR-EH00 system changed with the melt index (0.25g / 10min→0.3g / 10min→0.35g / 10min) from 76KJ / m 2 Reduced to 66KJ / m 2， Reduce to 55 KJ / m 2 The melting point increased from 146.1℃ to 146.9℃, and then to 147.6℃. For every 0.05g / 10min change in the melt index, the impact strength of the material changed between 13.16% and 16.7%, and the melting point changed between 0.55% and 0.47%.

[0053] Analysis of the test data results of Comparative Examples 4-6 shows that for every 0.05 g / 10 min change in melt index, the impact strength of the material changes by 13.09-8.69%, and the melting point changes by 0.13-0.2%.

[0054] Analysis of the test data of Comparative Examples 7-9 shows that for every 0.05 g / 10 min change in melt index, the impact strength of the material changes by 12.9% to 7.9%, and the melting point changes by 0.82% to 0.62%.

[0055] Comparative Examples 10-15 showed a significant stiffening effect on the resin, but also substantially reduced its impact strength, failing to meet the stable impact performance requirements of this invention. The impact strength of Comparative Examples 16-18 and 19-21 in Table 6 fluctuated significantly, with the largest variation exceeding 20% ​​as the melt index changed (0.25 g / 10 min → 0.3 g / 10 min → 0.35 g / 10 min).

[0056] Analysis of the test data results of Examples 1-18 in Table 4 shows that, after adding the nucleating agent, the performance of the polypropylene pipe material system changes with the melt index (0.25g / 10min → 0.3g / 10min → 0.35g / 10min). Under the same addition amount (Examples 4, 10, and 16), the notched impact strength of the simply supported beam can be increased from the original 85KJ / m. 2 Reduced to 84KJ / m 2， Reduced to 82KJ / m 2 The variation range is between 1.1% and 2.3%; the melting point of the polypropylene pipe material system can be 145.2℃, 145.2℃, and 145.6℃, with a variation range of approximately 0.27%. It is evident that the variation range of impact strength and melting point is very small. Overall, data analysis of examples with different melt indices and the same additive amount shows that the variation range of notched impact strength and melting point of the simply supported beam is not significant, indicating stable product performance.

[0057] As can be seen from the above data, the embodiments of the present invention can overcome the fluctuations in impact strength and melting point caused by changes in resin melt index (MFR), and have a very significant effect on stabilizing product quality.

[0058] In summary, the polypropylene pipe material prepared by introducing the specific nucleating agent compound system described in this application into the polypropylene pipe material system has the characteristics of high rigidity, low melting point, and stable product quality, which can meet the user's requirements for high toughness, low melting point, and stable product quality for hot and cold water transportation pipes.

[0059] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention. Adding other functional additives to the preparation components of the present invention to give the composite material corresponding properties is also protected by the present invention.

Claims

1. A high-impact, low-melting-point polypropylene material, comprising the following components by weight percentage: Polypropylene resin 99.70%–99.99%; Nucleating agent A: 0.005%–0.15%; Nucleating agent B: 0.005%–0.16%; The nucleating agent A is a metal salt of cyclohexanedicarboxylate; The nucleating agent B is a basic carbonate.

2. The high-impact, low-melting-point polypropylene material according to claim 1, characterized in that... Contains the following components by weight percentage: Polypropylene resin content: 99.76%–99.94%; preferably 99.82%–99.92%. Nucleating agent A: 0.03%–0.11%; preferably 0.03%–0.08%; Nucleating agent B: 0.03%–0.13%; preferably 0.05%–0.10%.

3. The high-impact, low-melting-point polypropylene material according to claim 1, characterized in that: The nucleating agent A is at least one of (1R,2S)-rel-1,2-cyclohexanedicarboxylate sodium salt, trans-1,4-cyclohexanedicarboxylate sodium salt, and 1,3-cyclohexanedicarboxylate sodium salt, preferably (1R,2S)-rel-1,2-cyclohexanedicarboxylate sodium salt.

4. The high-impact, low-melting-point polypropylene material according to claim 1, characterized in that: The nucleating agent B is at least one of basic magnesium carbonate, basic calcium carbonate, and basic magnesium calcium carbonate; preferably, it is basic magnesium calcium carbonate.

5. The high-impact, low-melting-point polypropylene material according to claim 1, characterized in that: The polypropylene resin is a random copolymer polypropylene; preferably, the comonomer of the random copolymer polypropylene is ethylene; more preferably, the mass content of the repeating unit of the ethylene monomer is 3.0% to 4.5%, preferably 3.4% to 3.6%.

6. The high-impact, low-melting-point polypropylene material according to claim 1, characterized in that: The melt flow index of the polypropylene resin is 0.2-0.4 g / 10 min (test conditions 230℃, 2.16 kg), preferably 0.25-0.35 g / 10 min (test conditions 230℃, 2.16 kg); And / or, The molecular weight distribution of the polypropylene resin is 4 to 7, preferably 5 to 6.

7. A pipe comprising the polypropylene material having high impact resistance and low melting point as described in any one of 1 to 6.

8. The method for preparing a polypropylene material with high impact resistance and low melting point according to any one of claims 1 to 6, characterized in that... Includes the following steps: The components, including polypropylene, nucleating agent A, and nucleating agent B, are mixed evenly and then melt-blended to obtain the final product.

9. The product obtained by the method for preparing polypropylene material with high impact resistance and low melting point according to claim 8.

10. The application of the polypropylene material with high impact resistance and low melting point according to any one of claims 1 to 6 and 9, preferably in the field of home decoration building materials and pipes.

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