A low-temperature resistant PP drainage pipe and its preparation method

Abstract

The present invention relates to the technical field of polypropylene drain pipes, and provides a low-temperature resistant PP drain pipe and a preparation method thereof. A low-temperature resistant PP drain pipe comprises the following raw materials in parts by weight: 100 parts of random copolymerized polypropylene, 3-5 parts of ethylene-vinyl acetate copolymer, 5-10 parts of butadiene-pyridine rubber, 10-15 parts of filler, 3-5 parts of lubricant, 1-1.5 parts of antioxidant, 0.5-1.5 parts of vulcanizing agent, and 0.5-1 part of nucleating agent. Through the above technical solution, the problem of poor low-temperature impact resistance of PP drain pipes in the related art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of polypropylene drain pipes, and specifically, to a low-temperature resistant PP drain pipe and a preparation method thereof. Background Art

[0002] PP drain pipes are drain pipes mainly made of polypropylene. Compared with traditional cast iron pipes or steel pipes, they are much lighter in weight, which makes them more convenient in transportation and installation, reduces labor intensity and construction costs, and due to their good insulation performance and recyclability, they are widely used in many fields such as construction, municipal administration, and industrial drainage. Traditional PP drain pipes can basically meet the drainage requirements under normal temperature environments. However, with the continuous expansion of usage scenarios and the increasingly harsh environmental conditions, many defects have emerged.

[0003] In cold regions or low-temperature working conditions, the disadvantages of ordinary PP drain pipes are particularly significant. Due to the characteristics of PP materials themselves, their glass transition temperature is relatively high. When the environmental temperature decreases, the movement of molecular chains is restricted, and the flexibility of the drain pipes drops sharply and becomes extremely brittle. For example, in winter in the north, the outdoor temperature often drops below -10°C or even lower. In such a low-temperature environment, ordinary PP drain pipes are slightly impacted by external forces, such as the heavy pressure of snow or collisions during installation, and may crack or even break, leading to the failure of the drainage system and causing a series of problems such as water leakage and sewage overflow, which not only causes environmental pollution but also may damage infrastructure. Therefore, it is necessary to develop a low-temperature impact-resistant PP drain pipe. Summary of the Invention

[0004] The present invention provides a low-temperature resistant PP drain pipe and a preparation method thereof, which solves the problem of poor low-temperature impact resistance of PP drain pipes in related technologies.

[0005] The technical solution of the present invention is as follows: The present invention provides a low-temperature resistant PP drain pipe, which comprises the following raw materials in parts by weight: 100 parts of random copolymer polypropylene, 3 - 5 parts of ethylene-vinyl acetate copolymer, 5 - 10 parts of butadiene pyridine rubber, 10 - 15 parts of filler, 3 - 5 parts of lubricant, 1 - 1.5 parts of antioxidant, 0.5 - 1.5 parts of vulcanizing agent, and 0.5 - 1 part of nucleating agent.

[0006] As a further technical solution, the mass ratio of the random copolymer polypropylene, the ethylene-vinyl acetate copolymer, and the butadiene pyridine rubber is 100:3:6 - 8.

[0007] The lubricant in the present invention can be any one or more conventional lubricants in the art, preferably one or both of calcium stearate and zinc stearate.

[0008] In the present invention, a lubricant is added, further optimizing the processing flow of the drain pipe, making the extrusion process smoother, reducing problems such as scratches and roughness on the surface of the drain pipe caused by friction during processing, making the surface of the drain pipe smoother and flatter. This not only improves the aesthetics of the drain pipe, but also reduces the frictional resistance between the water flow and the pipe wall to a certain extent during the drainage process, which is beneficial to improving the drainage efficiency; at the same time, the smooth surface is also less likely to adhere to dirt, facilitating cleaning and maintenance.

[0009] In the present invention, the antioxidant can be any one or more conventional antioxidants in the art, preferably one or more of antioxidant 168, antioxidant 626, and antioxidant 1076.

[0010] In the present invention, adding an antioxidant effectively inhibits the oxidative degradation reaction of the drain pipe during processing and use, ensuring the performance stability of the drain pipe during long-term use. When subjected to external pressure, water flow impact or environmental stress, the drain pipe added with an antioxidant can better maintain its structural integrity and avoid performance deterioration caused by material oxidation.

[0011] In the present invention, the vulcanizing agent can be any one or more conventional vulcanizing agents in the art, preferably one or more of benzoyl peroxide, dicumyl peroxide, and di-tert-butyl peroxide.

[0012] In the present invention, the addition of the vulcanizing agent can initiate cross-linking reactions between polymer molecules such as random copolymerized polypropylene, ethylene-vinyl acetate copolymer, and butadiene-acrylonitrile rubber. The formation of the cross-linked structure makes the molecular chains of the drain pipe connected to each other, improving the strength and hardness of the drain pipe. When subjected to external pressure, it can more effectively disperse stress and reduce the risk of deformation and rupture.

[0013] In the present invention, the nucleating agent can be any one or more conventional nucleating agents in the art, preferably one or two of nucleating agent TMB-5 and nucleating agent WBG-II.

[0014] In the present invention, the addition of the nucleating agent can provide a large number of crystal nuclei during the crystallization process of polymers such as polypropylene, further refining the crystal grain size. The fine crystal grains intersect with each other to form a more compact structure, enabling the drain pipe to better transfer stress when under pressure and ensuring the long-term stable operation of the drainage system.

[0015] As a further technical solution, the filler comprises the following raw material components in parts by weight: 15 parts of wollastonite, 0-3 parts of silane disulfide compound, and 10 parts of calcium carbonate.

[0016] In the present invention, calcium carbonate and wollastonite are rich in resources and have low market prices. The addition of calcium carbonate and wollastonite can effectively reduce the production cost of PP drain pipes, and the addition of calcium carbonate and wollastonite can also significantly enhance the strength of PP drain pipes, playing a role similar to that of a reinforcing skeleton in PP drain pipes based on PP as the matrix. Moreover, PP drain pipes are mainly used to transport sewage during use, and the sewage contains various chemical substances, including but not limited to detergent components in domestic sewage (containing surfactants, alkaline substances, etc.), grease in kitchen sewage, and organic acids generated by the decomposition of food residues, heavy metal ions, acids, alkalis, etc. that may be contained in industrial sewage. Calcium carbonate and wollastonite have stable chemical properties, so the addition of the two can also improve the corrosion resistance of PP drain pipes.

[0017] As a further technical solution, the filler comprises the following raw material components in parts by weight: 15 parts of wollastonite, 2 - 3 parts of silane disulfide compound, and 10 parts of calcium carbonate.

[0018] As a further technical solution, the silane disulfide compound comprises bis(triethoxysilylpropyl) disulfide.

[0019] In the present invention, using wollastonite, calcium carbonate, and bis(triethoxysilylpropyl) disulfide as raw materials to prepare a filler can, while improving the compatibility between wollastonite and the random copolymer polypropylene matrix material, effectively resist the erosion of acid and alkali substances, slow down the corrosion rate of the drain pipe, and extend the service life of the drain pipe.

[0020] As a further technical solution, the average particle size of the wollastonite is 200 - 400 mesh.

[0021] As a further technical solution, the calcium carbonate is heavy calcium carbonate with an average particle size of 325 - 400 mesh.

[0022] The present invention also provides a method for preparing a low-temperature resistant PP drain pipe, comprising the following steps:

[0023] S1. Dispersing the raw materials of the filler in a solvent, mixing, filtering, and drying to obtain the filler;

[0024] S2. Mixing ethylene-vinyl acetate copolymer, butadiene pyridine rubber, and antioxidant, and performing mixing to obtain a mixed rubber;

[0025] S3. Mixing the remaining raw materials, the filler, and the mixed rubber, performing mixing again, and then extruding and vulcanizing to obtain the low-temperature resistant PP drain pipe.

[0026] As a further technical solution, the mixing time in step S2 is 5 - 10 min, and the re-mixing time in step S3 is 10 - 15 min.

[0027] In the present invention, the mixing is carried out in two steps during the preparation of the PP drainage pipe. First, ethylene-vinyl acetate copolymer, butadiene-pyridine rubber and antioxidant are mixed to obtain a mixed rubber. At this time, the ethylene-vinyl acetate copolymer and butadiene-pyridine rubber can be better fused. Then, the mixed rubber is added to the remaining other components for another mixing. The process of step-by-step mixing can promote better mutual dispersion and interaction of the three components at the microscopic level, improving the impact performance of the drainage pipe. If the step-by-step mixing form is not adopted, uneven dispersion is likely to occur during the raw material mixing process, resulting in a situation where the ethylene-vinyl acetate copolymer and butadiene-pyridine rubber components are excessive in some local areas and too little in other areas. During application, the areas with less components are prone to crack first, leading to a decline in the overall low-temperature impact resistance of the drainage pipe and affecting the service life of the drainage pipe.

[0028] As a further technical solution, the solvent in step S1 is acetone.

[0029] The working principle and beneficial effects of the present invention are as follows:

[0030] In the present invention, random copolymer polypropylene is used as the basic raw material to provide the basic strength of the drainage pipe. Ethylene-vinyl acetate copolymer and butadiene-pyridine rubber are added to make the molecular chain have better flexibility and provide good low-temperature elasticity for the drainage pipe. The three are used in combination to improve the low-temperature impact resistance of the pp drainage pipe. Specific embodiments

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present invention.

[0032] In the following examples and comparative examples:

[0033] Random copolymer polypropylene: model is PP-R B4101;

[0034] Ethylene-vinyl acetate copolymer: model is UE639-04;

[0035] Butadiene rubber: model is BR9000;

[0036] Polyethylene: model is LD608;

[0037] Butadiene-pyridine rubber: model is YT-14, manufacturer is Jiangsu Yatai Chemical Co., Ltd.;

[0038] Wollastonite: average particle size is 400 mesh;

[0039] Calcium carbonate: The average particle size is 400 mesh.

[0040] Example 1

[0041] A preparation method of a low-temperature resistant PP drainage pipe, comprising the following steps:

[0042] S1. Disperse 15 parts of wollastonite and 10 parts of calcium carbonate in 250 parts of acetone. After mixing for 2 h, filter and dry to obtain a filler.

[0043] S2. Mix 3 parts of ethylene-vinyl acetate copolymer, 5 parts of butadiene-pyridine rubber, and 1 part of antioxidant 168. After kneading for 5 min, obtain a kneaded rubber.

[0044] S3. Weigh 100 parts of random copolymerized polypropylene, 0.5 part of benzoyl peroxide, 3 parts of calcium stearate, and 0.5 part of nucleating agent TMB-5. Add the kneaded rubber and 10 parts of the filler and mix. After kneading for 15 min, extrude, vulcanize, and cool to obtain the low-temperature resistant PP drainage pipe.

[0045] Example 2

[0046] A preparation method of a low-temperature resistant PP drainage pipe, comprising the following steps:

[0047] S1. Disperse 15 parts of wollastonite and 10 parts of calcium carbonate in 250 parts of acetone. After mixing for 2 h, filter and dry to obtain a filler.

[0048] S2. Mix 4 parts of ethylene-vinyl acetate copolymer, 8 parts of butadiene-pyridine rubber, and 1.2 parts of antioxidant 626. After kneading for 8 min, obtain a kneaded rubber.

[0049] S3. Weigh 100 parts of random copolymerized polypropylene, 1 part of dicumyl peroxide, 4 parts of calcium stearate, and 0.8 part of nucleating agent TMB-5. Add the kneaded rubber and 12 parts of the filler and mix. After kneading for 12 min, extrude, vulcanize, and cool to obtain the low-temperature resistant PP drainage pipe.

[0050] Example 3

[0051] A preparation method of a low-temperature resistant PP drainage pipe, comprising the following steps:

[0052] S1. Disperse 15 parts of wollastonite and 10 parts of calcium carbonate in 250 parts of acetone. After mixing for 2 h, filter and dry to obtain a filler.

[0053] S2. Mix 5 parts of ethylene-vinyl acetate copolymer, 10 parts of butadiene-pyridine rubber, and 1.5 parts of antioxidant 1076. After kneading for 10 min, obtain a kneaded rubber.

[0054] S3. Weigh 100 parts of random copolymer polypropylene, 1.5 parts of di-tert-butyl peroxide, 5 parts of zinc stearate, and 1 part of nucleating agent WBG-II. Add them to the mixed rubber and 15 parts of filler and mix. After mixing for 10 minutes, extrude, vulcanize, and cool to obtain the low-temperature resistant PP drainage pipe.

[0055] Example 4

[0056] Compared with Example 1, the difference in Example 4 is that, on the premise of ensuring the total mass of ethylene-vinyl acetate copolymer and butadiene pyridine rubber remains unchanged, 3 parts of ethylene-vinyl acetate copolymer and 5 parts of butadiene pyridine rubber are replaced with ethylene-vinyl acetate copolymer and butadiene pyridine rubber with a mass ratio of 1:2.

[0057] Example 5

[0058] Compared with Example 1, the difference in Example 5 is that, on the premise of ensuring the total mass of ethylene-vinyl acetate copolymer and butadiene pyridine rubber remains unchanged, 3 parts of ethylene-vinyl acetate copolymer and 5 parts of butadiene pyridine rubber are replaced with ethylene-vinyl acetate copolymer and butadiene pyridine rubber with a mass ratio of 3:8.

[0059] Example 6

[0060] A preparation method of a low-temperature resistant PP drainage pipe includes the following steps:

[0061] S1. Disperse 15 parts of wollastonite and 10 parts of calcium carbonate in 250 parts of acetone. After mixing for 2 hours, filter and dry to obtain the filler.

[0062] S2. Mix 3 parts of ethylene-vinyl acetate copolymer, 5 parts of butadiene pyridine rubber, 1 part of antioxidant 168, 100 parts of random copolymer polypropylene, 0.5 part of benzoyl peroxide, 3 parts of calcium stearate, 0.5 part of nucleating agent TMB-5, and 10 parts of filler. After mixing for 20 minutes, extrude, vulcanize, and cool to obtain the low-temperature resistant PP drainage pipe.

[0063] Example 7

[0064] Compared with Example 5, the difference in Example 7 lies in step S1. In this example, step S1 is: Disperse 2 parts of bis(triethoxysilylpropyl) disulfide in 250 parts of acetone, add 15 parts of wollastonite and 10 parts of calcium carbonate, mix for 2 hours, filter and dry to obtain the filler.

[0065] Example 8

[0066] Compared with Example 7, the difference in Example 8 is that the addition amount of bis(triethoxysilylpropyl) disulfide is 3 parts.

[0067] Comparative Example 1

[0068] Compared with Example 1, the difference in Comparative Example 1 is that the ethylene-vinyl acetate copolymer is replaced with an equal amount of butadiene-acrylonitrile rubber.

[0069] Comparative Example 2

[0070] Compared with Example 1, the difference in Comparative Example 2 is that the butadiene-acrylonitrile rubber is replaced with an equal amount of ethylene-vinyl acetate copolymer.

[0071] Comparative Example 3

[0072] Compared with Example 1, the difference in Comparative Example 3 is that the butadiene-acrylonitrile rubber is replaced with an equal amount of polyethylene.

[0073] Comparative Example 4

[0074] Compared with Example 1, the difference in Comparative Example 4 is that the butadiene-acrylonitrile rubber is replaced with an equal amount of cis-1,4-polybutadiene rubber.

[0075] Experimental Example 1

[0076] The low-temperature resistant PP drain pipes prepared in Examples 1 to 6 and Comparative Examples 1 to 4 were tested according to the following method:

[0077] 1. Impact resistance at normal temperature: According to the test method specified in GB / T 1043.2-2018 Plastics - Determination of Charpy impact properties - Part 2: Instrumented impact test, the Charpy impact strength of the notched specimen was tested. The specimen type was 1, the notch type was A, the impact direction was lateral, and the temperature was 23 °C.

[0078] 2. Impact resistance at low temperature: According to the test method specified in GB / T 1043.2-2018 Plastics - Determination of Charpy impact properties - Part 2: Instrumented impact test, the Charpy impact strength of the notched specimen was tested. The specimen type was 1, the notch type was A, the impact direction was lateral, and the temperature was -20 °C.

[0079] The test results are shown in Table 1:

[0080] Table 1 Performance test results of low-temperature resistant PP drain pipes prepared in Examples 1 to 6 and Comparative Examples 1 to 4

[0081]

[0082] Compared with Comparative Examples 1 to 4, the Charpy impact strength of the PP drain pipes prepared in Examples 1 to 6 at 23 °C was as high as 56.1 kJ / m 2 above, and the Charpy impact strength at -20 °C was as high as 5.4 kJ / m 2 above, indicating that the use of random copolymer polypropylene, ethylene-vinyl acetate copolymer and butadiene-acrylonitrile rubber in combination can improve the low-temperature impact resistance of PP drain pipes.

[0083] Experimental Example 2

[0084] For the low-temperature resistant PP drain pipes prepared in Example 5, Example 7, and Example 8, according to the test method specified in GB / T 11547-2008 "Determination of the Properties of Plastics Resistance to Liquid Chemical Reagents", the acid and alkali resistance properties of the samples were tested. The test conditions were as follows: The samples were respectively immersed in a hydrochloric acid solution with a mass concentration of 10% and a sodium carbonate solution with a mass concentration of 10%. The immersion temperature was 23°C, and the immersion time was 1 week.

[0085] The test results are shown in Table 2:

[0086] Table 2 Performance test results of the low-temperature resistant PP drain pipes prepared in Example 5, Example 7, and Example 8

[0087]

[0088] Compared with Example 5, the simple beam impact strength of Example 7 and Example 8 decreased less after immersion in hydrochloric acid and sodium carbonate solutions, indicating that when the filler includes wollastonite, calcium carbonate, and bis(triethoxysilylpropyl) disulfide, the acid and alkali resistance properties of the PP drain pipe can be improved.

[0089] Experimental Example 3

[0090] For the low-temperature resistant PP drain pipe prepared in Example 1, according to the test method specified in GB / T 18742.2-2017 "Polypropylene Pipe Systems for Cold and Hot Water - Part 2: Drain Pipes", a hydrostatic test was carried out. The test conditions were as follows: The media inside and outside were both water, and a Type A end cap was used.

[0091] The test results are shown in Table 3:

[0092] Table 3 Performance test results of the low-temperature resistant PP drain pipe prepared in Example 1

[0093]

[0094] As can be seen from Table 3, the PP drain pipes prepared by the present invention all meet the standards after the hydrostatic test and have good application value.

[0095] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low-temperature resistant PP drainage pipe, characterized in that, It comprises the following raw materials in parts by weight: 100 parts of random copolymer polypropylene, 3 - 5 parts of ethylene-vinyl acetate copolymer, 5 - 10 parts of butadiene pyridine rubber, 10 - 15 parts of filler, 3 - 5 parts of lubricant, 1 - 1.5 parts of antioxidant, 0.5 - 1.5 parts of vulcanizing agent, and 0.5 - 1 part of nucleating agent.

2. The low-temperature resistant PP drainage pipe according to claim 1, characterized in that, The lubricant includes one or both of calcium stearate and zinc stearate.

3. The low-temperature resistant PP drain pipe according to claim 1, characterized in that, The antioxidant includes one or more of antioxidant 168, antioxidant 626, and antioxidant 1076.

4. A low-temperature resistant PP drainage pipe according to claim 1, characterized in that, The vulcanizing agent includes one or more of benzoyl peroxide, dicumyl peroxide, and di-tert-butyl peroxide.

5. The low-temperature resistant PP drain pipe according to claim 1, characterized in that, The nucleating agent includes one or both of nucleating agent TMB-5 and nucleating agent WBG-II.

6. The low-temperature resistant PP drain pipe according to claim 1, characterized in that, The filler comprises the following raw materials in parts by weight: 15 parts of wollastonite, 0 - 3 parts of silane disulfide compound, and 10 parts of calcium carbonate.

7. The low-temperature resistant PP drain pipe according to claim 6, characterized in that, The average particle size of the wollastonite is 200 - 400 mesh.

8. A low-temperature resistant PP drainage pipe according to claim 6, characterized in that, The calcium carbonate is heavy calcium carbonate with an average particle size of 325 - 400 mesh.

9. The preparation method of a low-temperature resistant PP drain pipe according to any one of claims 1 to 8, characterized in that, It includes the following steps: S1. Disperse the raw materials of the filler in a solvent, mix them, filter and dry to obtain the filler. S2. Mix the ethylene-vinyl acetate copolymer, butadiene pyridine rubber, and antioxidant, and carry out mixing and kneading to obtain a kneaded rubber. S3. Mix the remaining raw materials, the filler, and the kneaded rubber, carry out secondary mixing and kneading, and then extrude and vulcanize to obtain a low-temperature resistant PP drainage pipe.

10. The preparation method of a low-temperature resistant PP drainage pipe according to claim 9, characterized in that, The mixing and kneading time in step S2 is 5 - 10 min, and the secondary mixing and kneading time in step S3 is 10 - 15 min.

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