Modified polypropylene plastic cable protection pipe and preparation method thereof

Abstract

The application provides a modified polypropylene plastic cable protection pipe and a preparation method thereof. The modified polypropylene plastic cable protection pipe comprises the following components in parts by weight: polypropylene masterbatch 70-100 parts, modified polypropylene 20-40 parts, lubricant 0.3-2 parts, stabilizer 0.5-2 parts, and pigment 0.1-0.5 parts; the modified polypropylene is prepared by blending the polypropylene masterbatch, styrene block copolymer, functional additive and lubricant. The modified polypropylene plastic cable protection pipe prepared by the application has high ring stiffness and Vicat softening temperature, and the crushing experiment, drop hammer impact and aging resistance are qualified, which indicates that the pipe has strong external pressure resistance, good mechanical properties, high toughness, is not easy to break or damage, and has good aging resistance and long service life.

Description

Technical Field

[0001] This invention belongs to the field of cable protection pipe technology, and particularly relates to a modified polypropylene plastic cable protection pipe and its preparation method. Background Technology

[0002] Polypropylene plastic cable protection pipes are widely used in underground cable laying projects due to their advantages such as light weight, corrosion resistance, and convenient construction. They need to withstand the pressure of backfill soil, dynamic and static loads from ground vehicles, chemical corrosion, and complex environmental climates.

[0003] Traditional protective pipes have poor impact toughness and are prone to brittle fracture during transportation, installation, or when subjected to external impacts. Their flexural modulus and tensile strength are limited, resulting in low ring stiffness. When buried deep or located under roadways, the pipes are prone to creep deformation, flattening and collapse under long-term continuous dynamic loads, leading to a reduction in the pipe diameter and seriously threatening cable safety.

[0004] Existing technologies often improve rigidity by adding large amounts of inexpensive inorganic fillers such as calcium carbonate and talc, but this often sacrifices toughness and impact resistance, resulting in increased rigidity but decreased toughness. Alternatively, adding large amounts of toughening agents can improve toughness, but this often damages the material's rigidity, strength, and heat resistance, and the material's long-term anti-aging properties are limited, making it difficult to meet service life standards.

[0005] In view of the problems existing in the prior art, how to provide a modified polypropylene plastic cable protection pipe with good impact resistance, good mechanical properties and aging resistance is the problem that this invention urgently needs to solve. Summary of the Invention

[0006] The purpose of this invention is to provide a modified polypropylene plastic cable protection pipe and its preparation method, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides a modified polypropylene plastic cable protection pipe, characterized in that it comprises the following components in parts by weight: 70-100 parts of polypropylene masterbatch, 20-40 parts of modified polypropylene, 0.3-2 parts of lubricant, 0.5-2 parts of stabilizer, and 0.1-0.5 parts of pigment; wherein the modified polypropylene is prepared by blending polypropylene masterbatch, styrene block copolymer, functional additives and lubricant.

[0008] As a further improvement, the synthesis of the modified polypropylene includes the following steps:

[0009] (1) Add sodium 2,2'-methylene bis(4,6-di-tert-butylphenyl) phosphate and organic solvent to a flask and stir until completely dissolved. Then slowly add aluminum trichloride hexahydrate solution dropwise. After the addition is complete, heat and reflux for 3-5 hours. After the reaction is completed, perform post-treatment to obtain the functional additive.

[0010] (2) Polypropylene masterbatch, styrene block copolymer, functional additives and lubricant are added to a mixer and mixed to obtain a blend powder, which is then extruded and granulated by a twin-screw extruder to obtain modified polypropylene.

[0011] As a further improvement, the amount of functional additive added in step (2) is 4-8% of the mass of polypropylene masterbatch added in step (2).

[0012] The functional additive is a phosphate hydroxyaluminate salt, which can change the crystal morphology of the polymer, reduce the size of the polymer spheres, and thus improve the rigidity and strength of the polymer. The functional additive is synergistically prepared with polypropylene masterbatch, styrene block copolymer and lubricant to obtain modified styrene, and then applied to polypropylene masterbatch to prepare plastic cable protection pipes. This can improve the toughness of the cable protection pipes, making them less brittle when subjected to external impact, and can also improve low temperature stability to a certain extent.

[0013] As a further improvement, the mass ratio of polypropylene masterbatch to styrene block copolymer in step (2) is 4-6:1.

[0014] As a further improvement, the mass ratio of the polypropylene masterbatch to the modified polypropylene is 2-5:1.

[0015] As a further improvement, the synthesis of the stabilizer includes the following steps:

[0016] 3-Hydroxy-4-methoxybenzaldehyde was dissolved in an organic solvent to prepare solution one; 6-aminopurine was dissolved in an organic solvent to prepare solution two; solution one was slowly added dropwise to a flask containing solution two, and then the mixture was heated under reflux and stirred for 5-8 hours. After the reaction was completed, the stabilizer was obtained through post-treatment.

[0017] 3-Hydroxy-4-methoxybenzaldehyde contains phenolic and aldehyde groups in its structure, exhibiting high reactivity and antioxidant and antibacterial properties. However, it is easily affected by environmental changes and is unstable. Reacting 3-hydroxy-4-methoxybenzaldehyde with 6-aminopurine can synergistically enhance its antioxidant properties, thermal and photo-oxidative stability, and environmental stability to a certain extent.

[0018] As a further improvement, the lubricant is at least one of calcium stearate, zinc stearate, polypropylene wax, and polyethylene wax.

[0019] Preferably, the lubricant is calcium stearate.

[0020] As a further improvement, the pigment is an orange-yellow pigment.

[0021] This invention also provides a method for preparing a modified polypropylene plastic cable protection tube, characterized by comprising the following steps:

[0022] (1) Under stirring conditions, polypropylene masterbatch, modified polypropylene, lubricant, stabilizer and pigment are added to the mixer in sequence and stirred evenly to obtain a blend.

[0023] (2) The blend is extruded, sized, and cooled by a screw extruder to obtain a modified polypropylene plastic cable protection pipe.

[0024] As a further improvement, the extrusion molding temperature is 180-220°C.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] This invention provides a modified polypropylene plastic cable protection pipe and its preparation method. The modified polypropylene plastic cable protection pipe has high ring stiffness and Vicat softening temperature. Furthermore, it passes the flattening test, drop hammer impact test, and aging resistance test, indicating that it has strong resistance to external pressure, good mechanical properties, high toughness, and is not prone to cracking or damage. In addition, it has good aging resistance and a long service life.

[0027] Blending polypropylene masterbatch with modified polypropylene can improve the toughness of the polypropylene masterbatch, making it less prone to cracking or damage under external impact, and maintaining a relatively high ring stiffness to a certain extent. The addition of stabilizers can improve the aging resistance of cable protection pipes, and the thermal and photo-oxidative stability are also high, thus enhancing the service life of the material. Detailed Implementation

[0028] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0029] In the following examples, except for the modified polypropylene and stabilizer, all other compound monomers and related reagents used were commercially available. The polypropylene masterbatch was purchased from Zhongtian Hechuang Energy Co., Ltd., with the grade K8003; the styrene block copolymer was purchased from Guangdong Gongchuang New Materials Co., Ltd., with the product number YH-502t; the pigment was orange pigment, purchased from Jiangyuan Masterbatch Co., Ltd., with the model number JEY-3017-3; and the EPDM rubber was purchased from Dow Chemical Co., Ltd., with the grade 3760.

[0030] The synthesis of modified polypropylene 1 includes the following steps:

[0031] (1) Take 30.6g of sodium 2,2'-methylenebis(4,6-di-tert-butylphenyl) phosphate and 250mL of methanol and add them to a flask. Stir at 40℃ until completely dissolved. Then slowly add 15mL of aluminum trichloride hexahydrate solution with a concentration of 3mol / L. After the addition is complete, reflux at 70℃ for 4h. After the reaction is complete, cool to room temperature and adjust the pH to 7 with sodium hydroxide solution with a concentration of 1mol / L. After standing for 15min, filter and wash with water 3 times. Dry under vacuum at 80℃ to obtain the functional additive.

[0032] (2) 100g of polypropylene masterbatch, 20g of styrene block copolymer, 5g of functional additives and 4g of calcium stearate were added to a mixer and mixed to obtain a blend powder. Then, the powder was extruded and granulated by a twin-screw extruder to obtain modified polypropylene 1.

[0033] The synthesis of modified polypropylene 2 includes the following steps:

[0034] 100g of polypropylene masterbatch, 20g of styrene block copolymer, 5g of EPDM rubber and 4g of calcium stearate were added to a mixer and blended to obtain a blend powder, which was then extruded and granulated through a twin-screw extruder to obtain modified polypropylene 2.

[0035] The synthesis of stabilizers includes the following steps:

[0036] 12.2 g of 3-hydroxy-4-methoxybenzaldehyde was dissolved in 100 mL of methanol to prepare solution one; 5.4 g of 6-aminopurine was dissolved in 100 mL of methanol to prepare solution two; solution one was slowly added dropwise to a flask containing solution two, and then the mixture was refluxed and stirred at 70 °C for 6 h. After the reaction was completed, the liquid phase was filtered and retained. The product was recrystallized from ethyl acetate and dried under vacuum at 60 °C for 3 h to obtain the stabilizer.

[0037] The preparation methods of Examples 1-4 and Comparative Examples 1-3 include the following steps:

[0038] (1) Under stirring conditions, polypropylene masterbatch, modified polypropylene, lubricant, stabilizer and pigment are added to the mixer in sequence and stirred evenly to obtain a blend.

[0039] (2) The blend is extruded and sized (inner diameter 200mm, wall thickness 16.5mm) and cooled by a screw extruder at 180-220℃ to obtain a hollow modified polypropylene plastic cable protection pipe.

[0040] The components and their contents used in Examples 1-4 and Comparative Examples 1-3 are shown in Table 1 below:

[0041] Table 1

[0042]

[0043] The modified polypropylene plastic cable protection tubes prepared in Examples 1-4 and Comparative Examples 1-3 were subjected to ring stiffness, flattening test, drop hammer impact test, Vicat softening temperature test, and aging resistance test. The test methods are as follows:

[0044] Ring stiffness: Tested according to GB / T 9647-2015, with a compression rate of 10±0.5mm / min and a test temperature of 23±2℃;

[0045] Flattening test: The test shall be conducted in accordance with GB / T 9647-2015 using an electronic universal testing machine. When the sample is loaded to the point where the vertical deformation is 100% of the original inner diameter, the sample is considered qualified if no cracks or breaks appear.

[0046] Drop hammer impact: The test shall be conducted in accordance with GB / T 14152-2001, using a drop hammer impact tester, with a drop hammer mass of 12.5 kg and an impact height of (1200±0.01) mm. The sample shall be pretreated at (-5±2)℃ for 2 h and the test shall be completed within 30 s. The sample is considered qualified if no cracks or breaks appear.

[0047] Vicat softening temperature: According to GB / T 1633-2000, using A... 50 The method is to conduct the test;

[0048] Aging resistance: After aging treatment at 135℃ for 2 days, a drop hammer impact test was performed again.

[0049] The test results are shown in Table 2, as follows:

[0050] Table 2

[0051]

[0052] As can be seen from the test results of Example 1 and Comparative Examples 1-2 in Table 2, if the modified polypropylene prepared by blending polypropylene masterbatch, styrene block copolymer, functional additives and lubricant of the present invention is not used, or if conventional plasticizer (ethylene propylene diene monomer rubber) is used to replace the functional additives to prepare modified polypropylene, the resulting modified polypropylene plastic cable protection pipe has low ring stiffness and Vicat softening temperature, and fails the flattening test, drop hammer impact test and aging resistance test. This indicates that it has poor compressive strength, low toughness, poor heat resistance, and the material is prone to failure, which does not meet the usage standards for cable protection pipes.

[0053] As can be seen from the test results of Example 1 and Comparative Example 3, if a conventional oxidant is used to replace the stabilizer prepared in this invention, the modified polypropylene plastic cable protection pipe finally obtained fails the aging resistance test, has a short service life, poor environmental adaptability, and low ring stiffness and Vicat softening temperature, indicating that its compressive strength and toughness are also insufficient, and it is prone to cracks or damage.

[0054] As can be seen from the test results of Examples 1-4 in Table 2, the modified polypropylene plastic cable protection pipe prepared by the method provided by the present invention has high ring stiffness and Vicat softening temperature. Furthermore, its flattening test, drop hammer impact test, and aging resistance all pass the tests, indicating that the modified polypropylene plastic cable protection pipe prepared by the present invention has good resistance to external pressure, good mechanical properties, high toughness, and is not prone to cracking or damage. It also exhibits high aging resistance and a long service life. Moreover, the test results of Examples 1-3 and 4 show that when the mass ratio of polypropylene masterbatch to modified polypropylene is within a suitable range, the performance of the prepared modified polypropylene plastic cable protection pipe is even better.

[0055] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A modified polypropylene plastic cable protection pipe, characterized in that, The product comprises the following components in parts by weight: 70-100 parts polypropylene masterbatch, 20-40 parts modified polypropylene, 0.3-2 parts lubricant, 0.5-2 parts stabilizer, and 0.1-0.5 parts pigment; wherein the modified polypropylene is prepared by blending polypropylene masterbatch, styrene block copolymer, functional additives, and lubricant. The synthesis of the modified polypropylene includes the following steps: (1) Add sodium 2,2'-methylene bis(4,6-di-tert-butylphenyl) phosphate and organic solvent to a flask and stir until completely dissolved. Then slowly add aluminum trichloride hexahydrate solution dropwise. After the addition is complete, heat and reflux for 3-5 hours. After the reaction is completed, perform post-treatment to obtain the functional additive. (2) Polypropylene masterbatch, styrene block copolymer, functional additives and lubricant are added to a mixer and blended to obtain blend powder, which is then extruded and granulated through a twin-screw extruder to obtain modified polypropylene; The synthesis of the stabilizer includes the following steps: 3-Hydroxy-4-methoxybenzaldehyde was dissolved in an organic solvent to prepare solution one; 6-aminopurine was dissolved in an organic solvent to prepare solution two; solution one was slowly added dropwise to a flask containing solution two, and then the mixture was heated under reflux and stirred for 5-8 hours. After the reaction was completed, the stabilizer was obtained through post-treatment.

2. The modified polypropylene plastic cable protection pipe according to claim 1, characterized in that, The amount of functional additive added in step (2) is 4-8% of the mass of polypropylene masterbatch.

3. The modified polypropylene plastic cable protection pipe according to claim 1, characterized in that, In step (2), the mass ratio of polypropylene masterbatch to styrene block copolymer is 4-6:

1.

4. The modified polypropylene plastic cable protection pipe according to claim 1, characterized in that, The mass ratio of polypropylene masterbatch to modified polypropylene is 2-5:

1.

5. The modified polypropylene plastic cable protection pipe according to claim 1, characterized in that, The lubricant is at least one of calcium stearate, zinc stearate, polypropylene wax, and polyethylene wax.

6. The modified polypropylene plastic cable protection pipe according to claim 1, characterized in that, The pigment is an orange-yellow pigment.

7. A method for preparing a modified polypropylene plastic cable protection pipe according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Under stirring conditions, polypropylene masterbatch, modified polypropylene, lubricant, stabilizer and pigment are added to the mixer in sequence and stirred evenly to obtain a blend. (2) The blend is extruded, sized, and cooled by a screw extruder to obtain a modified polypropylene plastic cable protection pipe.

8. The method for preparing a modified polypropylene plastic cable protection pipe according to claim 7, characterized in that, The extrusion temperature in step (2) is 180-220℃.

Images