PE material for reinforced rib composite pipe, preparation method and reinforced rib PE composite pipe

Abstract

The present invention belongs to the technical field of polyethylene materials for pipelines, in particular to the technical field of polyethylene materials for reinforced composite pipes. The present invention discloses a PE material for reinforced composite pipes and a reinforced composite pipe prepared by the material, by adding a certain amount of styrene-butadiene-styrene (SBS) triblock copolymer and polystyrene- b ‑Polyethylene glycol block copolymer is used as a reinforced pipe composite material. The reinforced pipe composite material prepared by simple swelling treatment has excellent external pressure resistance and improved inner wall hydrophilicity.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyethylene materials for pipes, especially the technical field of polyethylene materials for reinforced composite pipes. Background Art

[0002] Polyethylene (PE) materials have been widely used in the field of pipeline manufacturing due to their excellent corrosion resistance, wear resistance and good flexibility. However, the performance of a single PE material may not meet the requirements in certain specific application scenarios, such as high pressure, high temperature or highly corrosive environments. Therefore, combining PE materials with other high-strength materials to form composite pipes has become an effective way to improve pipeline performance.

[0003] Reinforced polyethylene (PE) composite pipe is a new type of composite material pipe, which combines the corrosion resistance, wear resistance and flexibility of PE material with the high strength and pressure resistance of reinforcing materials (such as steel wire, glass fiber, etc.), significantly improving the pressure bearing capacity and impact resistance of the pipe. This composite pipe is usually composed of two layers of PE material inside and outside and reinforcing ribs in the middle. The reinforcing ribs can be high-strength materials such as steel wire and glass fiber, which are distributed along the length of the pipe to provide additional support and strength for the pipe.

[0004] In addition, some advanced reinforced polyethylene composite pipes also use special connection methods and coating technologies. For example, by setting flange connection plates at both ends of the pipe, the pipe can be easily connected and disassembled quickly. At the same time, applying anti-corrosion coatings on the inner and outer walls of the pipe can further improve the corrosion resistance and service life of the pipe.

[0005] This reinforced polyethylene PE composite pipe has many advantages, such as high strength, corrosion resistance, wear resistance, temperature resistance, aging resistance, etc. They can be used in a wide temperature range, have strong adaptability, and have various connection methods, fast installation speed and low cost. At the same time, because the PE material can be recycled, this composite pipe also has good environmental performance.

[0006] However, at present, there is little development in the field of PE materials used. The modification of PE materials used is usually to apply a coating and add a reinforcing material for improvement. However, the above method usually causes problems such as limited service life of the coating and easy shedding, poor dispersion of the reinforcing material in polyethylene and weak bonding with polyethylene. In addition, a large amount of reinforcing agents are often required to improve the toughness and strength of the pipeline, which significantly increases the production cost.

[0007] For example, in the prior art, such as patent document CN118061492A, coconut charcoal fiber is added to HDPE material to improve corrosion resistance, delay PE pipe aging, and enhance the strength of the pipe. CN106633533A adds a composite toughening agent, and the composite toughening agent is pre-compounded with elastic polymer, dispersant and nano-montmorillonite, which can play a buffering role and improve the compatibility effect, achieving the advantages of high rigidity and toughness. However, the polyvinyl chloride material, composite lead heat stabilizer and other additives used in this solution have certain toxicity and are only suitable for conventional material transmission. In addition, the raw materials are mainly hydrophobic materials, which have unfavorable factors in antibacterial and anti-pollution performance and transmission of aqueous fluids.

[0008] In order to solve the above problems, a PE material suitable for reinforcing rib composite pipes is provided which has strong toughness, certain antibacterial properties and is modified to be stable and durable. Summary of the invention

[0009] A PE material for a reinforced rib composite pipe comprises polyethylene, styrene-butadiene-styrene (SBS) triblock copolymer and polystyrene-b-polyethylene glycol block copolymer.

[0010] Preferably, in the PE material, the mass ratio of polyethylene to styrene-butadiene-styrene (SBS) triblock copolymer is 3-6:2; the mass ratio of styrene-butadiene-styrene (SBS) triblock copolymer to polystyrene-b-polyethylene glycol block copolymer is 40-60:1.

[0011] Preferably, the molecular weight of styrene-butadiene-styrene (SBS) is 70,000-100,000 g·mol -1 The mass proportion of styrene in SBS is 30-40%.

[0012] Preferably, the molecular weight of PS-b-PEG is 50,000-70,000 g·mol -1 , the mass ratio of PS segment to PEG segment is 1:5-10.

[0013] Preferably, the mass ratio of the PS segment to the PEG segment is 1:8.

[0014] Preferably, the polyethylene is high density polyethylene or linear low density polyethylene.

[0015] A method for preparing a reinforced PE composite pipe: step 1, conveying the above PE material to a melt blending device, melting and mixing uniformly;

[0016] Step 2: Extrude the melt-blended material through an extrusion die, cool it, and post-process it to form a reinforced PE composite pipe.

[0017] Specifically, metal or hard plastic reinforcement ribs may be provided outside the PE pipe, or a metal wire mesh may be provided between or within the inner and outer PE layers. The specific reinforcement method is not limited and may be applied.

[0018] Preferably, the method further comprises step 3, subjecting the reinforced PE composite pipe obtained in step 2 to surface segregation and swelling treatment, heating ethanol to 70-75°, and immersing the reinforced PE composite pipe obtained in step 2 in the above solution for 18-36 hours to obtain a final reinforced PE composite pipe.

[0019] Preferably, the method further comprises step 3, subjecting the reinforced PE composite pipe obtained in step 2 to surface segregation and swelling treatment, selecting chloroform and ethanol to prepare a mixed solution, wherein the volume ratio of chloroform to ethanol is 1-2:9; heating the mixed solution of chloroform and ethanol to 70-75° C., and immersing the reinforced PE composite pipe obtained in step 2 in the above solution for 12-24 hours to obtain a final reinforced PE composite pipe.

[0020] A reinforced PE composite pipe is prepared by the above method.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. Add SBS to PE materials and use the viscoelasticity of SBS to improve the toughness of PE materials. At the same time, both are high molecular organic substances. According to the principle of similar compatibility and the entanglement of molecular chains during the melting and stirring process, the obtained PE material has higher dispersibility, uniformity and stability;

[0023] 2. PS-b-PEG block copolymer is added. The addition of the above polymer can introduce hydrophilic segments into the PE material, thereby improving the hydrophilicity of the pipeline and improving the antibacterial properties of the material to a certain extent. Since PEG and PS segments are chemically bonded and have the same PS segments as SBS, PS-b-PEG can stably and uniformly improve the hydrophilicity;

[0024] 3. SBS has a certain elasticity at room temperature, and the material itself has low water absorption, which can avoid the problems of increased material brittleness and weakened strength caused by the swelling of block copolymers;

[0025] 4. For the prepared PE pipe, hot ethanol is used for surface segregation treatment, which can induce the PEG segments near the pipe wall to migrate to the pipe surface, improve the hydrophilicity of the inner wall of the pipe, and improve the antibacterial performance to a certain extent. At the same time, it is beneficial for the transportation of aqueous fluids. However, due to the low content of PS-b-PEG block copolymer, it is impossible to form a continuous pore structure, thereby avoiding pipe seepage.

[0026] 5. For the prepared PE tube, the obtained PE material is swollen with a mixed solution of chloroform and ethanol. Under the action of a specific swelling temperature and solvent, the PEG segments in the block copolymer PS-b-PEG undergo microscopic phase transfer to form a nanopore structure in a local area, that is, an uneven and discontinuous local pore structure is formed inside the PE material. The uniformly distributed pore structure inside and the elastic properties of SBS at room temperature enable the PE material to form a cushioning structure similar to that of an airbag, further improving the toughness, tensile and compressive strength of the material; at the same time, the PEG segments near the tube wall are induced to migrate to the surface of the pipe, improving the hydrophilicity of the inner wall of the pipe. DETAILED DESCRIPTION

[0027] Example 1

[0028] The materials were selected according to the mass fraction of high-density polyethylene: styrene-butadiene-styrene (SBS): polystyrene-b-polyethylene glycol block copolymer equal to 60:40:1. The molecular weight of SBS is 80,000 g / mol, and the mass proportion of styrene segments is 35%; the molecular weight of PS-b-PEG is 50,000 g / mol, and the mass ratio of PS to PEG segments is 1:5.

[0029] The above materials are blended, and the melt-blended materials are extruded through an extrusion die, cooled, post-processed and formed into a reinforced PE composite pipe; chloroform and ethanol are prepared to prepare a mixed solution, the volume ratio of chloroform to ethanol is 1:9, the mixed solution is heated to 70°C, and the reinforced PE composite pipe is immersed in the above solution for 18 hours to finally obtain a reinforced PE composite pipe (DN225).

[0030] Example 2

[0031] Compared with Example 1, the difference is that the mass fraction of the selected PS-b-PEG block copolymer is 60000 g / mol.

[0032] Example 3

[0033] Compared with Example 1, the difference is that the mass fraction of the selected PS-b-PEG block copolymer is 70000 g / mol.

[0034] Comparative Example 1

[0035] Compared with Example 1, the difference is that the mass fraction of the selected PS-b-PEG block copolymer is 100000 g / mol.

[0036] Comparative Example 2

[0037] Compared with Example 1, the difference is that the mass fraction of the selected PS-b-PEG block copolymer is 40000 g / mol.

[0038] Example 4

[0039] Compared with Example 1, the difference is that the mass ratio of PS to PEG segments in the selected PS-b-PEG block copolymer is 1:8.

[0040] Example 5

[0041] Compared with Example 1, the difference is that the mass ratio of PS to PEG segments in the selected PS-b-PEG block copolymer is 1:10.

[0042] Comparative Example 3

[0043] Compared with Example 1, the difference is that the mass ratio of PS to PEG segments in the selected PS-b-PEG block copolymer is 1:12.

[0044] Comparative Example 4

[0045] Compared with Example 1, the difference is that the mass ratio of PS to PEG segments in the selected PS-b-PEG block copolymer is 1:3.

[0046] Example 6

[0047] Compared with Example 1, the difference is that in the prepared chloroform and ethanol mixed solution, the volume ratio of chloroform to ethanol is 2:9.

[0048] Comparative Example 5

[0049] Compared with Example 1, the difference is that in the prepared chloroform and ethanol mixed solution, the volume ratio of chloroform to ethanol is 1:10.

[0050] Comparative Example 6

[0051] Compared with Example 1, the difference is that in the prepared chloroform and ethanol mixed solution, the volume ratio of chloroform to ethanol is 3:9.

[0052] Example 7

[0053] Compared with Example 1, the difference is that pure ethanol solvent is used to replace the mixed solution of chloroform and ethanol.

[0054] Comparative Example 7

[0055] After high-density polyethylene is used as a raw material and mixed evenly, the melt-blended material is extruded through an extrusion die, cooled, and post-processed to form a reinforced PE composite pipe; chloroform and ethanol are prepared to prepare a mixed solution, the volume ratio of chloroform to ethanol is 1:9, the mixed solution is heated to 70°C, and the reinforced PE composite pipe is immersed in the above solution for 18 hours to finally obtain a reinforced PE composite pipe (DN225).

[0056] Comparative Example 8

[0057] After high-density polyethylene is used as the raw material and mixed evenly, the melt-blended material is extruded through an extrusion die, cooled, post-processed and formed into a reinforced PE composite pipe (DN225).

[0058] Comparative Example 9

[0059] The materials were selected according to the mass fraction of high-density polyethylene: styrene-butadiene-styrene (SBS) equal to 60:40. The molecular weight of SBS was 80,000 g / mol, and the mass proportion of the styrene chain segment was 35%.

[0060] The above materials are blended, and the melt-blended materials are extruded through an extrusion die, cooled, post-processed and formed into a reinforced PE composite pipe; chloroform and ethanol are prepared to prepare a mixed solution, the volume ratio of chloroform to ethanol is 1:9, the mixed solution is heated to 70°C, and the reinforced PE composite pipe is immersed in the above solution for 18 hours to finally obtain a reinforced PE composite pipe (DN225).

[0061] Comparative Example 10

[0062] The materials were selected according to the mass fraction of high-density polyethylene: styrene-butadiene-styrene (SBS) equal to 60:40. The molecular weight of SBS was 80,000 g / mol, and the mass proportion of the styrene chain segment was 35%.

[0063] The above materials are blended, and the melt-blended materials are extruded through an extrusion die, cooled, post-processed and formed into a reinforced PE composite pipe (DN225).

[0064] The toughness of the pipeline is measured and tested according to GB / T14152-2001 standard.

[0065] Among them, the experimental conditions of the 0°C drop hammer impact test are: the hammer head of the drop hammer is d90 type, the drop hammer mass is 15Kg, and the drop height is 2m.

[0066] The experimental conditions of the -10°C drop hammer impact test are: the hammer head of the drop hammer is d90 type, the drop hammer mass is 15Kg, and the drop height is 1m

[0067] The experimental conditions of the -20°C drop hammer impact test are: the hammer head of the drop hammer is d90 type, the weight of the drop hammer is 15 kg, and the drop height is 1 m. In addition, the water contact angle of the inner wall material of the pipeline is measured.

[0068] The experimental conditions of the -30°C drop hammer impact test are: the hammer head of the drop hammer is d90 type, the weight of the drop hammer is 15 kg, and the drop height is 1 m. In addition, the water contact angle of the inner wall material of the pipeline is measured.

[0069] The test results are shown in Table 1:

[0070] Table 1

[0071] 0°C drop hammer impact test TIR (%) -10°C drop hammer impact test TIR (%) -20°C drop hammer impact test TIR (%) -30°C drop hammer impact test TIR (%) Inner wall water contact angle (°) Example 1 ≤10 ≤10 ≤10 ≤10 61 Example 2 ≤10 ≤10 ≤10 ＞10 60 Example 3 ≤10 ≤10 ≤10 ＞10 60 Comparative Example 1 ≤10 ≤10 ＞10 ＞10 65 Comparative Example 2 ≤10 ≤10 ＞10 ＞10 60 Example 4 ≤10 ≤10 ≤10 ≤10 62 Example 5 ≤10 ≤10 ≤10 ≤10 59 Comparative Example 3 ≤10 ≤10 ＞10 ＞10 56 Comparative Example 4 ≤10 ≤10 ＞10 ＞10 74 Example 6 ≤10 ≤10 ≤10 ≤10 66 Comparative Example 5 ≤10 ≤10 ＞10 ＞10 72 Comparative Example 6 ≤10 ＞10 ＞10 ＞10 79 Example 7 ≤10 ≤10 ＞10 ＞10 82 Comparative Example 7 ≤10 ＞10 ＞10 ＞10 87 Comparative Example 8 ≤10 ＞10 ＞10 ＞10 88 Comparative Example 9 ≤10 ≤10 ＞10 ＞10 86 Comparative Example 10 ≤10 ≤10 ＞10 ＞10 85

[0072] According to Example 1, it can be seen from the analysis of Comparative Examples 7-10 that adding a certain elastic SBS material to a pure PE reinforcing rib pipe can improve the external impact resistance and toughness of the pipeline. In addition, after adding a small amount of PS-b-PEG block copolymer and swelling, the pressure resistance of the pipeline can be significantly improved and the hydrophilicity of the inner wall of the pipeline can be modified. The reason may be that the immersion in the mixed solvent of chloroform and ethanol plays a role in surface segregation, and the PEG segments near the inner wall of the pipeline undergo microscopic phase transfer and enrichment on the inner wall surface of the pipeline. In addition, under the action of the mixed solvent, the PEG segments of the PS-b-PEG block copolymer in the tube wall swell and the microscopic phase transfer forms discontinuous nanopores in the tube wall (the amount of PS-b-PEG block copolymer is very small), combined with the elastic properties of the SBS material, a microstructure similar to an airbag will be formed, further enhancing the external impact resistance and toughness of the pipeline. For the tube without adding block copolymer (Comparative Examples 7-10), the swelling agent has basically no effect on the tube.

[0073] According to the analysis of Examples 1-3 and Comparative Examples 1-2, as the molecular weight of the added PS-b-PEG increases, the impact resistance decreases slightly (Examples 1-3), and when the molecular weight is too large (Comparative Example 1), the impact resistance decreases significantly. When the molecular weight is too small (Comparative Example 2), the impact resistance of the pipeline also decreases significantly. The reason may be that when the molecular weight is too large, the molecular chain is too long, resulting in an increased probability of entanglement of the PEG chain segments in the pipeline and a decrease in distribution uniformity. The microscopic air bag structure formed after swelling is unevenly distributed and uneven in size, which in turn causes a certain degree of decrease in external impact resistance. When the molecular weight is too small, the block copolymer may be eluted under the action of the high-temperature swelling agent to form defects (when the integrity test of the pipeline was conducted, it was found that the pipeline would seep under high pressure, which also confirmed this speculation).

[0074] According to the analysis of Examples 1, 4-5 and Comparative Examples 3-4, the mass ratio of the PEG segments in the added PS-b-PEG can be selected within a certain range as required. However, when the mass ratio of the PEG segments is too large, it is easy to cause uneven swelling due to the excessive length of the PEG segments and poor binding force between the block copolymer and the PE / SBS material due to the short PS segments, thereby causing defects; when the mass ratio of the PEG segments is too small, the increase in the volume of the PEG segments caused by swelling may be difficult to break through the elastic force of the SBS, and after the swelling is completed, the elastic force of the SBS basically returns to its original state and the microscopic airbag structure cannot be formed.

[0075] According to Examples 1, 6-7 and Comparative Examples 5-6, when ethanol or a small amount of chloroform is added for swelling (Example 7 and Comparative Example 5), the hydrophilicity of the inner wall of the pipe can only be improved to a certain extent, but the improvement of the external pressure resistance performance is not obvious. Perhaps the different polarities of ethanol and the main materials PE and SBS make it difficult to penetrate and contact the block copolymer to swell. When the amount of chloroform is too much, it may cause defects in the dissolution of the material.

Claims

1. A reinforced PE composite pipe, comprising PE material, characterized in that: The PE material includes polyethylene, styrene-butadiene-styrene (SBS) triblock copolymer, polystyrene- b -Polyethylene glycol (PS- b -PEG) block copolymer; the mass ratio of polyethylene to styrene-butadiene-styrene (SBS) triblock copolymer in the PE material is 3-6:2; the mass ratio of styrene-butadiene-styrene (SBS) triblock copolymer to polystyrene- b -Polyethylene glycol (PS- b The mass ratio of styrene-butadiene-styrene (SBS) block copolymer is 70,000-100,000 g·mol -1 The mass proportion of styrene chain segments in SBS is 30-40%; PS- b -The molecular weight of PEG is 50,000-70,000 g·mol -1 , the mass ratio of PS segment to PEG segment is 1:5-10; The PE material is melt blended, extruded from a die, cooled, post-treated and immersed in a mixed solution of chloroform and ethanol at a temperature of 70-75° C. and a volume ratio of chloroform to ethanol of 1-2:9 for 12-24 hours to obtain the reinforced PE composite pipe.

2. A reinforced PE composite pipe according to claim 1, characterized in that: The mass ratio of PS segment to PEG segment is 1:

8.

3. The PE composite pipe with reinforcement ribs according to claim 1, characterized in that: The polyethylene is high density polyethylene or linear low density polyethylene.

4. A method for preparing a reinforced PE composite pipe according to any one of claims 1 to 3, characterized in that: Step 1, conveying the PE material to a melt blending device to melt and mix uniformly; Step 2, extruding the melt-blended material through an extrusion die, cooling, post-processing and forming a reinforced PE composite pipe; Step 3, subjecting the reinforced PE composite pipe obtained in step 2 to surface segregation swelling treatment, selecting chloroform and ethanol to prepare a mixed solution, wherein the volume ratio of chloroform to ethanol is 1-2:9; heating the mixed solution of chloroform and ethanol to 70-75° C., immersing the reinforced PE composite pipe obtained in step 2 in the above solution for 12-24 hours, and obtaining a final reinforced PE composite pipe.