Low-temperature-resistant PP drain pipe and preparation method thereof

Abstract

The invention relates to the technical field of polypropylene drainage pipes, and provides a low-temperature-resistant PP drainage pipe and a preparation method thereof. The low-temperature-resistant PP drain pipe is prepared from the following raw materials in parts by weight: 100 parts of polypropylene random copolymer, 3 to 5 parts of ethylene-vinyl acetate copolymer, 5 to 10 parts of butadiene-vinylpyridine rubber, 10 to 15 parts of filler, 3 to 5 parts of lubricant, 1 to 1.5 parts of antioxidant, 0.5 to 1.5 parts of vulcanizing agent and 0.5 to 1 part of nucleating agent. According to the technical scheme, the problem of poor low-temperature impact resistance of the PP drainage pipe in the related technology is solved.

Description

Technical Field

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

[0002] PP drainage pipes are drainage pipes made of polypropylene as the main raw material. Compared with traditional cast iron pipes or steel pipes, they are much lighter, which makes them more convenient in transportation and installation, reduces labor intensity and construction costs, and because of their good insulation and recyclability, they are widely used in many fields such as construction, municipal and industrial drainage. Traditional PP drainage pipes can basically meet drainage needs at room temperature, but with the continuous expansion of usage scenarios and increasingly harsh environmental conditions, many defects have been exposed.

[0003] The disadvantages of ordinary PP drainage pipes are particularly significant in cold areas or low-temperature working conditions. Due to the characteristics of PP materials themselves, their glass transition temperature is relatively high. When the ambient temperature drops, the movement of the molecular chain is restricted, the flexibility of the drainage pipe drops sharply, and it becomes extremely brittle. For example, in the winter in the north, the outdoor temperature is often below minus 10℃ or even lower. Ordinary PP drainage pipes in such a low-temperature environment may crack or even break if slightly impacted by external forces, such as the weight of snow and collisions during installation, which will lead to the failure of the drainage system, causing a series of problems such as leakage and sewage overflow, which will not only cause environmental pollution, but also damage infrastructure. Therefore, it is very necessary to develop a low-temperature impact-resistant PP drainage pipe. Summary of the invention

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

[0005] The technical solution of the present invention is as follows: The present invention proposes a low-temperature resistant PP drainage pipe, comprising the following component raw materials in parts by weight: 100 parts of random copolymer polypropylene, 3 to 5 parts of ethylene-vinyl acetate copolymer, 5 to 10 parts of butyl pyridine rubber, 10 to 15 parts of filler, 3 to 5 parts of lubricant, 1 to 1.5 parts of antioxidant, 0.5 to 1.5 parts of vulcanizer, and 0.5 to 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 butylpyrrolidone 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, lubricant is added to further optimize the processing flow of the drain pipe, making the extrusion process smoother, reducing scratches and roughness on the drain pipe surface caused by friction during the processing, and making the drain pipe surface smoother and flatter, which not only improves the aesthetics of the drain pipe, but also reduces the friction resistance between the water flow and the pipe wall during the drainage process to a certain extent, which is beneficial to improving the drainage efficiency; at the same time, the smooth surface is also less likely to adhere to dirt, which is convenient for cleaning and maintenance.

[0009] The antioxidant in the present invention 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, antioxidants are added to effectively inhibit 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 with added antioxidants can better maintain its structural integrity and avoid performance degradation caused by material oxidation.

[0011] The vulcanizing agent in the present invention 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 induce a cross-linking reaction between polymer molecules such as random copolymer polypropylene, ethylene-vinyl acetate copolymer and butylpyrrolidone rubber. The formation of the cross-linking structure enables the molecular chains of the drain pipe to be interconnected, thereby improving the strength and hardness of the drain pipe, so that it can more effectively disperse stress when subjected to external pressure and reduce the risk of deformation and rupture.

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

[0014] In the present invention, the addition of nucleating agent can provide a large number of crystal nuclei during the crystallization process of polymers such as polypropylene, further refine the grain size, and the fine grains are intertwined to form a tighter structure, so that the drainage pipe can better transmit stress when under pressure, ensuring the long-term stable operation of the drainage system.

[0015] As a further technical solution, the filler includes the following component raw materials 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 abundant in resources and low in market price. The addition of calcium carbonate and wollastonite can effectively reduce the production cost of PP drainage pipes, and the addition of calcium carbonate and wollastonite can also significantly enhance the strength of PP drainage pipes, and can play a similar role as reinforcing the skeleton in PP drainage pipes based on PP. Moreover, PP drainage pipes are mainly used to transport sewage during use. Sewage contains a variety of chemical substances, including but not limited to detergent components (containing surfactants, alkaline substances, etc.) in domestic sewage, organic acids produced by the decomposition of grease and food residues in kitchen sewage, and 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 drainage pipes.

[0017] As a further technical solution, the filler includes the following component raw materials in parts by weight: 15 parts of wollastonite, 2-3 parts of silane disulfide compounds, and 10 parts of calcium carbonate.

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

[0019] In the present invention, wollastonite, calcium carbonate and bis(triethoxysilylpropyl) disulfide are used as raw materials to prepare a filler, which improves the compatibility of wollastonite with a random copolymer polypropylene matrix material and effectively resists the erosion of acidic and alkaline substances, slows down the corrosion rate of the drainage pipe, and prolongs the service life of the drainage pipe.

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

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

[0022] The present invention also provides a method for preparing a low-temperature resistant PP drainage pipe, comprising the following steps: S1, dispersing the raw materials of the filler in a solvent, mixing, filtering and drying to obtain a filler; S2, mixing ethylene-vinyl acetate copolymer, butylpyrrolidone rubber and antioxidant, and kneading to obtain a rubber compound; S3, mixing the remaining raw materials, the filler and the mixed rubber, mixing again, extruding and vulcanizing to obtain a low-temperature resistant PP drainage pipe.

[0023] As a further technical solution, the mixing time in step S2 is 5 to 10 minutes, and the re-mixing time in step S3 is 10 to 15 minutes.

[0024] In the present invention, when preparing the PP drainage pipe, mixing is carried out twice. First, ethylene-vinyl acetate copolymer, butylpyrrolidone rubber and antioxidant are mixed to obtain a rubber mixture. At this time, the ethylene-vinyl acetate copolymer and butylpyrrolidone rubber can be better fused. Then the rubber mixture is added to the remaining other components and mixed again. The step-by-step mixing process can promote the three to better disperse and interact with each other at the microscopic level, thereby 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 mixing of the raw materials. There will be a situation where the ethylene-vinyl acetate copolymer and butylpyrrolidone rubber components are too much in some local areas, while too little in other areas. When used, the area with less components is likely to rupture first, resulting in a decrease in the overall low-temperature impact resistance of the drainage pipe, affecting the service life of the drainage pipe.

[0025] As a further technical solution, the solvent in step S1 is acetone.

[0026] The working principle and beneficial effects of the present invention are: In the present invention, random copolymer polypropylene is used as the basic raw material to provide the basic strength of the drainage pipe, and ethylene-vinyl acetate copolymer and butylpyrrolidone 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. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the following examples and comparative examples: Random copolymer polypropylene: model PP-R B4101; Ethylene-vinyl acetate copolymer: model UE639-04; Butadiene rubber: model BR9000; Polyethylene: Model LD608; Butylpyridine rubber: model is YT-14, manufacturer is Jiangsu Yatai Chemical Co., Ltd.; Wollastonite: average particle size is 400 mesh; Calcium carbonate: The average particle size is 400 mesh.

[0029] Example 1 A method for preparing a low-temperature resistant PP drainage pipe comprises the following steps: S1. Disperse 15 parts of wollastonite and 10 parts of calcium carbonate in 250 parts of acetone, mix for 2 hours, filter and dry to obtain a filler; S2, 3 parts of ethylene-vinyl acetate copolymer, 5 parts of butyl pyridine rubber, and 1 part of antioxidant 168 were mixed, and kneaded for 5 minutes to obtain a rubber mixture; S3. Weigh 100 parts of random copolymer polypropylene, 0.5 parts of benzoyl peroxide, 3 parts of calcium stearate, and 0.5 parts of nucleating agent TMB-5, add 10 parts of compound rubber and filler, mix for 15 minutes, extrude, vulcanize, and cool to obtain a low-temperature resistant PP drainage pipe.

[0030] Example 2 A method for preparing a low-temperature resistant PP drainage pipe comprises the following steps: S1. Disperse 15 parts of wollastonite and 10 parts of calcium carbonate in 250 parts of acetone, mix for 2 hours, filter and dry to obtain a filler; S2, 4 parts of ethylene-vinyl acetate copolymer, 8 parts of butyl pyridine rubber, and 1.2 parts of antioxidant 626 were mixed, and kneaded for 8 minutes to obtain a rubber mixture; S3. Weigh 100 parts of random copolymer polypropylene, 1 part of dicumyl peroxide, 4 parts of calcium stearate, and 0.8 parts of nucleating agent TMB-5, add 12 parts of compound rubber and filler, mix for 12 minutes, extrude, vulcanize, and cool to obtain a low-temperature resistant PP drainage pipe.

[0031] Example 3 A method for preparing a low-temperature resistant PP drainage pipe comprises the following steps: S1. Disperse 15 parts of wollastonite and 10 parts of calcium carbonate in 250 parts of acetone, mix for 2 hours, filter and dry to obtain a filler; S2, 5 parts of ethylene-vinyl acetate copolymer, 10 parts of butyl pyridine rubber, and 1.5 parts of antioxidant 1076 were mixed, and kneaded for 10 minutes to obtain a rubber mixture; 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 15 parts of compound rubber and filler, mix for 10 minutes, extrude, vulcanize, and cool to obtain a low-temperature resistant PP drainage pipe.

[0032] Example 4 Compared with Example 1, the difference of Example 4 is that, while ensuring that the total mass of ethylene-vinyl acetate copolymer and butylpyrrolidone rubber remains unchanged, 3 parts of ethylene-vinyl acetate copolymer and 5 parts of butylpyrrolidone rubber are replaced by ethylene-vinyl acetate copolymer and butylpyrrolidone rubber in a mass ratio of 1:2.

[0033] Example 5 Compared with Example 1, the difference of Example 5 is that, while ensuring that the total mass of ethylene-vinyl acetate copolymer and butylpyrrolidone rubber remains unchanged, 3 parts of ethylene-vinyl acetate copolymer and 5 parts of butylpyrrolidone rubber are replaced by ethylene-vinyl acetate copolymer and butylpyrrolidone rubber in a mass ratio of 3:8.

[0034] Example 6 A method for preparing a low-temperature resistant PP drainage pipe comprises the following steps: S1. Disperse 15 parts of wollastonite and 10 parts of calcium carbonate in 250 parts of acetone, mix for 2 hours, filter and dry to obtain a filler; S2. Mix 3 parts of ethylene-vinyl acetate copolymer, 5 parts of butyl pyridine rubber, 1 part of antioxidant 168, 100 parts of random copolymer polypropylene, 0.5 parts of benzoyl peroxide, 3 parts of calcium stearate, 0.5 parts of nucleating agent TMB-5 and 10 parts of filler, knead for 20 minutes, extrude, vulcanize and cool to obtain a low-temperature resistant PP drainage pipe.

[0035] Example 7 Compared with Example 5, the difference of Example 7 lies in step S1. In this embodiment, step S1 is: dispersing 2 parts of bis(triethoxysilylpropyl) disulfide in 250 parts of acetone, adding 15 parts of wollastonite and 10 parts of calcium carbonate, mixing for 2 hours, filtering and drying to obtain a filler.

[0036] Example 8 Compared with Example 7, the difference in Example 8 is that the added amount of bis(triethoxysilylpropyl)disulfide is 3 parts.

[0037] Comparative Example 1 Compared with Example 1, the difference of Comparative Example 1 is that the ethylene-vinyl acetate copolymer is replaced by an equal amount of butylpyrrolidone rubber.

[0038] Comparative Example 2 Compared with Example 1, the difference of Comparative Example 2 is that the butylpyrrolidone rubber is replaced by an equal amount of ethylene-vinyl acetate copolymer.

[0039] Comparative Example 3 Compared with Example 1, the difference in Comparative Example 3 is that the butylpyridine rubber is replaced by an equal amount of polyethylene.

[0040] Comparative Example 4 Compared with Example 1, the difference of Comparative Example 4 is that the butylpyrrolidone rubber is replaced by an equal amount of cis-1,4-dibutyl rubber.

[0041] Experimental Example 1 The low temperature resistant PP drainage pipes prepared in Examples 1 to 6 and Comparative Examples 1 to 4 were tested according to the following method: 1. Impact resistance at room temperature: According to the test method specified in GB / T 1043.2-2018 "Determination of impact properties of simply supported beams of plastics Part 2: Instrumented impact test", the simply supported beam impact strength of the notched specimen is tested. The specimen type is 1, the notch type is type A, the impact direction is lateral, and the temperature is 23°C.

[0042] 2. Low-temperature impact resistance: According to the test method specified in GB / T 1043.2-2018 "Determination of impact properties of simply supported beams of plastics Part 2: Instrumented impact test", the simply supported beam impact strength of the notched specimen is tested. The specimen type is 1, the notch type is type A, the impact direction is lateral, and the temperature is -20°C.

[0043] The test results are shown in Table 1: Table 1 Performance test results of low temperature resistant PP drainage pipes prepared in Examples 1 to 6 and Comparative Examples 1 to 4

[0044] Compared with comparative examples 1 to 4, the 23°C simply supported beam impact strength of the PP drainage pipes prepared in examples 1 to 6 is as high as 56.1 kJ / m 2 Above, -20℃ simply supported beam impact strength is up to 5.4kJ / m 2 The above shows that the combination of random copolymer polypropylene, ethylene-vinyl acetate copolymer and butylpyrrolidone rubber can improve the low-temperature impact resistance of PP drainage pipes.

[0045] Experimental Example 2 The low-temperature resistant PP drainage pipes prepared in Example 5 and Examples 7 and 8 were tested for acid and alkali resistance according to the test method specified in GB / T 11547-2008 "Determination of resistance of plastics to liquid chemical reagents". The test conditions were: immersed in a hydrochloric acid solution with a mass concentration of 10% and a sodium carbonate solution with a mass concentration of 10%, respectively, at a soaking temperature of 23°C and for 1 week.

[0046] The test results are shown in Table 2: Table 2 Performance test results of low temperature resistant PP drainage pipes prepared in Example 5 and Examples 7 and 8

[0047] Compared with Example 5, the simply supported beam impact strength of Examples 7 and 8 after immersion in hydrochloric acid and sodium carbonate solutions decreased less, indicating that when the filler includes wollastonite, calcium carbonate and bis(triethoxysilylpropyl) disulfide, the acid and alkali resistance of the PP drainage pipe can be improved.

[0048] Experimental Example 3 The low-temperature resistant PP drainage pipe prepared in Example 1 was subjected to a hydrostatic test according to the test method specified in GB / T18742.2-2017 "Polypropylene Piping System for Hot and Cold Water Part 2: Drainage Pipe". The test conditions were: the internal and external media were both water, and an A-type head was used.

[0049] The test results are shown in Table 3: Table 3 Performance test results of the low temperature resistant PP drainage pipe prepared in Example 1

[0050] It can be seen from Table 3 that the PP drainage pipes prepared by the present invention meet the standards after the hydrostatic test and have good application value.

[0051] The above are only 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 principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low temperature resistant PP drainage pipe, characterized in that: The invention 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 butyl pyridine rubber, 10-15 parts of filler, 3-5 parts of lubricant, 1-1.5 parts of antioxidant, 0.5-1.5 parts of vulcanizer and 0.5-1 parts of nucleating agent.

2. A 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 drainage pipe according to claim 1, characterized in that: The antioxidant includes one or more of antioxidant 168 , antioxidant 626 , and antioxidant 1076 .

4. The 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 drainage 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 drainage pipe according to claim 1, characterized in that: The filler comprises the following raw materials 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 drainage pipe according to claim 6, characterized in that: The average particle size of the wollastonite is 200-400 meshes.

8. The 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 meshes.

9. The method for preparing a low-temperature resistant PP drainage pipe according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, dispersing the raw materials of the filler in a solvent, mixing, filtering and drying to obtain a filler; S2, mixing ethylene-vinyl acetate copolymer, butylpyrrolidone rubber and antioxidant, and kneading to obtain a rubber compound; S3, mixing the remaining raw materials, the filler and the mixed rubber, mixing again, extruding and vulcanizing to obtain a low-temperature resistant PP drainage pipe.

10. The method for preparing a low-temperature resistant PP drainage pipe according to claim 9, characterized in that: The mixing time in step S2 is 5 to 10 minutes, and the re-mixing time in step S3 is 10 to 15 minutes.

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