CN112980084A

CN112980084A - High-strength PE (polyethylene) pipe and preparation method thereof

Info

Publication number: CN112980084A
Application number: CN202110452569.1A
Authority: CN
Inventors: 宫文朋; 刘雪飞; 李忠贤; 刘芍朋
Original assignee: Laiyang Yuansheng Plastic Industry Co ltd
Current assignee: Laiyang Yuansheng Plastic Industry Co ltd
Priority date: 2021-04-26
Filing date: 2021-04-26
Publication date: 2021-06-18
Anticipated expiration: 2041-04-26
Also published as: CN112980084B

Abstract

The technical scheme of the invention discloses a high-strength PE pipe, which comprises an environment-friendly PE inner pipe and a reinforced PE outer pipe, wherein the reinforced PE outer pipe surrounds the outer periphery of the environment-friendly PE inner pipe; the environment-friendly PE inner pipe comprises, by weight, 60-70 parts of high-density polyethylene, 3-6 parts of a polyolefin elastomer, 6-10 parts of nano calcium carbonate whiskers, 0.2-1 part of a silane coupling agent and 0.1-0.3 part of polyethylene wax; the reinforced PE outer pipe comprises 60-80 parts of polyethylene, 5-30 parts of regenerated silica, 2-10 parts of antioxidant, 0.5-2 parts of dispersant, 0.5-5 parts of toughening agent and 0.5-5 parts of paraffin; the regenerated silica comprises potash feldspar, potassium hydroxide, siliceous shale, waste glass, fly ash, a silane coupling agent, a dispersing agent, palmitic acid and deionized water. The strength of the PE pipe is obviously improved by the preparation and addition of the regenerated silica, and the PE pipe is environment-friendly and low in cost.

Description

High-strength PE (polyethylene) pipe and preparation method thereof

Technical Field

The invention relates to the technical field of PE pipe processing, in particular to a high-strength PE pipe and a preparation method thereof.

Background

The PE (polyethylene) pipe is one of the most common pipes, and is widely used in construction projects such as water supply, drainage, heat supply, gas supply, and the like. Polyethylene has the characteristics of no odor, no odor and no toxicity, is not easy to corrode by decaying substances in sewage, chemicals, soil and the like, but under the conditions of severe environment or large or heavy bearing capacity, the compressive strength, tensile strength and the like of the PE pipe cannot meet the corresponding requirements, and cannot meet the actual production and application. Aiming at the defect of strength of a PE pipe, the prior art improves the preparation process of the PE pipe, and one method is to change the structure of the pipe and arrange a multilayer structure to increase the structural strength; patent CN 110375125A discloses a green's PE tubular product, from inside to outside including hard polyvinyl chloride inner shell, enhancement layer, tubular product shell, polyimide temperature resistant layer, resistant oxidation layer, the inside reinforcing body that sets up of tubular product shell, the intensity of reinforcing tubular product, but the structure is complicated, and the preparation is troublesome, and is with high costs. The second is to modify the composition, e.g., add additional substances, modify PE, etc. CN 108233290B discloses a PE tubular product system of processing, has added raw materials such as quartz sand, glass steel, active carbon in PE tubular product, the intensity of reinforcing PE tubular product. In CN 106432879B, the mechanical strength, impact resistance and the like of the PE pipe are enhanced by hexamethylenediamine modified PE and adipic acid modified PE. However, the common steps for improving the components are complicated, the compatibility between the added components such as quartz sand and the like and the organic components is poor, the components are easy to seep out of the base material in the long-term use process, the performance stability of the PE pipe is influenced, the service life is influenced, and the cost is high.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention provides the high-strength PE pipe and the preparation method thereof, the strength of the PE pipe is obviously improved by preparing and adding the regenerated silica, and the PE pipe is environment-friendly and low in cost.

The technical scheme of the invention is as follows: a high-strength PE pipe comprises an environment-friendly PE inner pipe and a reinforced PE outer pipe, wherein the reinforced PE outer pipe surrounds the outer periphery of the environment-friendly PE inner pipe; the environment-friendly PE inner pipe comprises, by weight, 60-70 parts of high-density polyethylene, 3-6 parts of a polyolefin elastomer, 6-10 parts of nano calcium carbonate whiskers, 0.2-1 part of a silane coupling agent and 0.1-0.3 part of polyethylene wax; the reinforced PE outer pipe comprises, by weight, 60-80 parts of polyethylene, 5-30 parts of regenerated silica, 2-10 parts of an antioxidant, 0.5-2 parts of a dispersant, 0.5-5 parts of a toughening agent and 0.5-5 parts of paraffin;

the regenerated silica comprises potash feldspar, potassium hydroxide, siliceous shale, waste glass, fly ash, a silane coupling agent, a dispersing agent, palmitic acid and deionized water.

Further, the polyolefin elastomer is prepared by copolymerizing ethylene and octene; the antioxidant is one of triphenyl phosphite, calcium stearate and tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester; the dispersing agent is one of BYK-110, FS-5118 or BYK 163; the toughening agent is one of carboxymethyl cellulose, polyolefin elastomer or ethylene propylene diene monomer; the silane coupling agent comprises at least one of KH550, KH560 and KH 570.

A preparation method of a high-strength PE pipe comprises the following steps:

the method comprises the following steps of firstly, respectively taking 60-70 parts by weight of high-density polyethylene, 3-6 parts by weight of polyolefin elastomer, 6-10 parts by weight of nano calcium carbonate whisker, 0.2-1 part by weight of silane coupling agent and 0.1-0.3 part by weight of polyethylene wax, mixing and uniformly stirring to obtain an inner tube mixed raw material, placing the inner tube mixed raw material in a drying box for drying, then sending the dried inner tube mixed raw material into a double-screw extruder for melt blending and extrusion to prepare a molten inner tube mixed raw material;

step two, respectively taking 60-80 parts of polyethylene, 5-30 parts of regenerated silica, 2-10 parts of antioxidant, 0.5-2 parts of dispersant, 0.5-5 parts of flexibilizer and 0.5-5 parts of paraffin, mixing and uniformly stirring to obtain an outer tube mixed raw material, placing the outer tube mixed raw material in a drying box for drying, and then sending the outer tube mixed raw material into a double-screw extruder for melt blending and extrusion to prepare a molten outer tube mixed raw material;

guiding the inner pipe mixed raw material and the outer pipe mixed raw material in a molten state into a multi-layer co-extrusion die through a shunting feeding device respectively, and performing co-compression extrusion in the multi-layer co-extrusion die to obtain a hot pipe blank;

step four, respectively shaping, cooling in the first stage and cooling in the second stage of the hot tube blank in a vacuum state through a sizing sleeve vacuum sizing box; the temperature of the first stage cooling is-18 ℃ to-6 ℃, the time is 30min, the temperature of the second stage cooling is 4 ℃ to 9 ℃, and the time is 2 h; and cooling to obtain the PE pipe.

Further, the temperature of the melt blending in the first step and the second step is 200-220 ℃, and the time is 1-2 h; the temperature of the compression extrusion in the third step is 180-190 ℃, and the extrusion pressure is 10-20 MPa.

Further, the water content of the inner tube mixed raw material dried in the step one and the water content of the outer tube mixed raw material dried in the step two are less than 6%.

Further, in the third step, before the multilayer co-extrusion die is used, heat preservation is carried out for 20-30 min.

Furthermore, the split feeding device in the third step is a split plate.

Further, in the fourth step, the inner diameter of the sizing sleeve is 1-3 mm larger than the outer diameter of the PE pipe.

Further, the preparation method of the regenerated silica comprises the following steps:

s1, preparing potassium aluminosilicate, washing potassium feldspar through deionized water, crushing, grinding until the particle size is smaller than 300 meshes, mixing with a potassium hydroxide aqueous solution with the concentration of 4-8 mol/L, and putting into a high-pressure kettle, wherein the mass ratio of potassium feldspar to potassium hydroxide is 65-75: 26-35; carrying out hydrothermal reaction on potassium feldspar and potassium hydroxide in the high-pressure kettle at the reaction temperature of 140-180 ℃ for 6-24 hours; after the reaction is finished, filtering, washing with deionized water and drying to obtain potassium aluminosilicate;

s2, preparing coupled powder I, taking 80-90 parts of potassium aluminosilicate, 2-3 parts of a dispersing agent, 2-4 parts of a silane coupling agent and 16-26 parts of deionized water according to weight fraction, grinding for 9-12 h by a high-speed wet method until the particle size of the powder reaches 0.5-2 mu m, and obtaining the coupled powder I;

s3, preparing coupled powder II, taking 50-70 parts of siliceous shale, 20-30 parts of waste glass and 10-20 parts of fly ash according to weight fraction, grinding the siliceous shale, the waste glass and the fly ash until the particle size is less than 300 meshes, mixing to form a raw material mixture I, taking 70-80 parts of the raw material mixture I, 2-3 parts of a dispersing agent, 60-70 parts of palmitic acid, 2-3 parts of a silane coupling agent and 15-20 parts of deionized water, grinding for 9-12 h by a high-speed wet method until the particle size of the powder II reaches 0.5-2 mu m, and obtaining the coupled powder II;

and S4, uniformly mixing 70-85 parts by weight of coupled powder I and 15-30 parts by weight of coupled powder II, and performing spray drying to obtain the regenerated silica.

In the high-strength PE pipe, potassium feldspar reacts with a potassium hydroxide aqueous solution to generate potassium aluminosilicate, the concentration, the reaction temperature and the reaction time of the potassium hydroxide aqueous solution are strictly limited, the concentration is low, the reaction time is too short, and the potassium feldspar cannot be completely converted into the potassium aluminosilicate due to too low reaction temperature, so that the impurity content is too high; and the waste of resources is caused by overhigh concentration, overlong reaction time and overhigh reaction temperature.

The prepared potassium aluminosilicate has high purity, and the coupled powder I has high thickness-diameter ratio, low specific surface area and low oil absorption value through modification of a silane coupling agent and a dispersing agent, so that the potassium aluminosilicate has very excellent dispersibility and dispersibility aid, the dispersibility, compatibility and interface strength with a polyethylene matrix are obviously improved, the potassium aluminosilicate has a lubricating effect on materials in an extrusion process to reduce the flowing viscosity of the materials and improve the melt flowing rate, so that the reinforced PE outer pipe is filled more fully in an injection molding process, meanwhile, the coupled powder I has ultrahigh elastic modulus and can greatly improve the shrinkage rate of the PE outer pipe due to the high diameter-thickness ratio, and the impact strength and the mechanical property of the reinforced PE outer pipe are greatly improved.

Siliceous shale, waste glass and fly ash contain a large amount of silicon dioxide, aluminum oxide and the like, and after the siliceous shale, the waste glass and the fly ash react with a dispersant, palmitic acid and a silane coupling agent, the coupled powder II can greatly improve the strength of a polyethylene matrix and has good dispersibility. The purpose of palmitic acid is to adjust the surface energy, lubricity and oil absorption value of siliceous shale, waste glass and fly ash. The coupling powder I and the coupling powder II are mixed according to a certain proportion to prepare the regenerated silica, so that the reutilization of siliceous shale, waste glass and fly ash can be realized, the environment friendliness is facilitated, the dispersibility is good, and the strength of the polyethylene matrix is obviously improved.

The silane coupling agent improves the structure of two-phase interface layers, improves the interface bonding force and improves the material strength. The antioxidant is a compound with higher oxidation resistance, and can slow down the aging degree of the pipe, thereby improving the overall service life and stability of the pipe. The polyolefin elastomer in the environment-friendly PE inner pipe is equivalent to a physical crosslinking point when the material bears load, and plays a role in evenly distributing the load. The nano calcium carbonate crystal whisker has an ultra-large length-diameter ratio, can enable high-density polyethylene molecules to form a space network structure with the nano calcium carbonate crystal whisker, has a large specific surface area, can be combined with more high-density polyethylene molecules, and can form a more compact network structure, thereby remarkably improving the strength of the environment-friendly PE inner pipe. In addition, the materials used in the environment-friendly PE inner pipe are non-toxic and harmless, the prepared PE inner pipe does not pollute liquid transported in the pipe, the environment is not polluted, and the environment-friendly performance of the pipe is improved.

The environmental-friendly PE inner pipe not only properly improves the strength of the pipe, but also is non-toxic and pollution-free, and ensures the safety of the transported liquid; simultaneously, the strength of the pipe is obviously improved through the reinforced PE outer pipe, and the reinforced PE outer pipe surrounds the outer periphery of the environment-friendly PE inner pipe, so that the reinforced PE outer pipe carries out auxiliary support on the environment-friendly PE inner pipe, the pressure of the environment-friendly PE inner pipe is shared, and the strength of the whole PE pipe is enhanced.

In the preparation method of the high-strength PE pipe, after the shaped heat pipe blank is shaped in a vacuum state, a staged cooling method is adopted, the temperature of the first stage cooling is-18 ℃ to-6 ℃, the time is 30min, and the rapid cooling stage is adopted; the temperature of the second stage of cooling is 4-9 ℃, and the time is 2h, so that the PE pipe is fully cooled, and the mechanical strength of the PE pipe can be improved.

The internal tube mixed raw materials and the external tube mixed raw materials are melted and blended through a double-screw extruder, the temperature and time of the melting and blending are limited, and the raw materials can be fully melted and uniformly mixed. The temperature and the time of co-compression extrusion in the multi-layer co-extrusion die are limited, and heat preservation is carried out before use, so that the forming of a hot tube blank is facilitated, the difficult or waste of forming caused by the early solidification of the inner tube mixed raw material and the outer tube mixed raw material in a molten state is prevented, higher temperature does not need to be kept, and the waste of energy is avoided. The inner tube mixed raw material and the outer tube mixed raw material are dried until the water content is less than 6%, so that the time consumed by the melting and blending step is less, the efficiency is higher, and the mixing state is more uniform.

By adopting the technical scheme, the invention has the following beneficial effects:

(1) the strength of the environment-friendly PE inner pipe is properly improved, and the environment-friendly PE inner pipe is non-toxic and harmless and has no pollution to the environment; the reinforced PE outer pipe is high in strength, and is matched with the environment-friendly PE inner pipe structure, so that the strength of the whole pipe is obviously enhanced.

(2) The raw materials of potassium feldspar and siliceous shale in the reinforced PE outer pipe are easy to obtain, the waste glass and the fly ash are recycled, the cost is low, the environmental protection is facilitated, and the resources are saved.

(3) The production method is simple, the preparation process can be realized by using the existing equipment, the operation is easy, the cost is low, the performance is stable, and the service life is long.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

Example 1

A high-strength PE pipe comprises an environment-friendly PE inner pipe and a reinforced PE outer pipe, wherein the reinforced PE outer pipe surrounds the outer periphery of the environment-friendly PE inner pipe; the environment-friendly PE inner pipe comprises 65g of high-density polyethylene, 5g of polyolefin elastomer, 8g of nano calcium carbonate whisker, 0.5g of silane coupling agent and 0.2g of polyethylene wax; the reinforced PE outer pipe comprises 70g of polyethylene, 15g of regenerated silica, 6g of antioxidant, 1g of dispersant, 3g of toughening agent and 3g of paraffin;

Further, the polyolefin elastomer is prepared by copolymerizing ethylene and octene; the antioxidant is triphenyl phosphite; the dispersant is BYK-110; the toughening agent is carboxymethyl cellulose; the silane coupling agent is KH 550.

A preparation method of a high-strength PE pipe comprises the following steps:

step one, respectively taking 65g of high-density polyethylene, 5g of polyolefin elastomer, 8g of nano calcium carbonate whisker, 0.5g of silane coupling agent and 0.2g of polyethylene wax, mixing and stirring uniformly to obtain an inner tube mixed raw material, placing the inner tube mixed raw material in a drying box for drying, then sending the inner tube mixed raw material into a double-screw extruder for melt blending and extrusion to prepare a molten inner tube mixed raw material;

step two, respectively taking 70g of polyethylene, 15g of regenerated silica, 6g of antioxidant, 1g of dispersant, 3g of toughening agent and 3g of paraffin, mixing and stirring uniformly to obtain an outer tube mixed raw material, placing the outer tube mixed raw material in a drying box for drying, and then sending the outer tube mixed raw material into a double-screw extruder for melt blending and extrusion to prepare a molten outer tube mixed raw material;

step four, respectively shaping, cooling in the first stage and cooling in the second stage of the hot tube blank in a vacuum state through a sizing sleeve vacuum sizing box; the temperature of the first stage cooling is-12 deg.C, the time is 30min, the temperature of the second stage cooling is 6 deg.C, and the time is 2 h; and cooling to obtain the PE pipe.

Further, the temperature of the melt blending in the first step and the second step is 210 ℃, and the time is 1.5 h; the temperature of the compression extrusion in the third step is 180 ℃, and the extrusion pressure is 20 MPa.

Further, in the third step, before the multilayer co-extrusion die is used, the temperature is kept for 20 min.

Furthermore, the split feeding device in the third step is a split plate.

Further, in the fourth step, the inner diameter of the sizing sleeve is 2mm larger than the outer diameter of the PE pipe.

s1, preparing potassium aluminosilicate, washing potassium feldspar through deionized water, crushing, grinding to a particle size smaller than 300 meshes, mixing with a potassium hydroxide aqueous solution with the concentration of 6mol/L, and putting into a high-pressure kettle, wherein the mass of the potassium feldspar is 70g, and the mass of the potassium hydroxide is 28 g; carrying out hydrothermal reaction on potassium feldspar and potassium hydroxide in the high-pressure kettle at the reaction temperature of 160 ℃ for 12 hours; after the reaction is finished, filtering, washing with deionized water and drying to obtain potassium aluminosilicate;

s2, preparing coupled powder I, taking 85g of potassium aluminosilicate, 3g of dispersant, 3g of silane coupling agent and 23g of deionized water, and grinding for 10 hours by a high-speed wet method until the particle size of the powder reaches 1 mu m to obtain the coupled powder I;

s3, preparing coupled powder II, taking 60g of siliceous shale, 25g of waste glass and 15g of fly ash, grinding the siliceous shale, the waste glass and the fly ash to a particle size of less than 300 meshes, mixing to obtain a raw material mixture I, taking 75g of the raw material mixture I, 2g of a dispersing agent, 65g of palmitic acid, 3g of a silane coupling agent and 18g of deionized water, grinding for 10 hours by a high-speed wet method until the particle size of the powder II reaches 1 mu m, and obtaining the coupled powder II;

s4, uniformly mixing 80g of coupled powder I and 20g of coupled powder II, and performing spray drying to obtain the regenerated silica.

Example 2

A high-strength PE pipe comprises an environment-friendly PE inner pipe and a reinforced PE outer pipe, wherein the reinforced PE outer pipe surrounds the outer periphery of the environment-friendly PE inner pipe; the environment-friendly PE inner pipe comprises 60g of high-density polyethylene, 3g of polyolefin elastomer, 6g of nano calcium carbonate whisker, 0.2g of silane coupling agent and 0.1g of polyethylene wax; the reinforced PE outer pipe comprises 60g of polyethylene, 5g of regenerated silica, 2g of antioxidant, 0.5g of dispersant, 0.5g of toughening agent and 0.5g of paraffin;

Further, the polyolefin elastomer is prepared by copolymerizing ethylene and octene; the antioxidant is calcium stearate; the dispersant is FS-5118; the toughening agent is ethylene propylene diene monomer; the silane coupling agent is KH 560.

A preparation method of a high-strength PE pipe comprises the following steps:

step one, respectively taking 60g of high-density polyethylene, 3g of polyolefin elastomer, 6g of nano calcium carbonate whisker, 0.2g of silane coupling agent and 0.1g of polyethylene wax, mixing and stirring uniformly to obtain an inner tube mixed raw material, placing the inner tube mixed raw material in a drying box for drying, then sending the inner tube mixed raw material into a double-screw extruder for melt blending and extrusion to prepare a molten inner tube mixed raw material;

step two, respectively taking 60g of polyethylene, 5g of regenerated silica, 2g of antioxidant, 0.5g of dispersant, 0.5g of flexibilizer and 0.5g of paraffin, mixing and stirring uniformly to obtain an outer tube mixed raw material, placing the outer tube mixed raw material in a drying box for drying, and then sending the outer tube mixed raw material into a double-screw extruder for melt blending and extrusion to prepare a molten outer tube mixed raw material;

step four, respectively shaping, cooling in the first stage and cooling in the second stage of the hot tube blank in a vacuum state through a sizing sleeve vacuum sizing box; the temperature of the first stage cooling is-18 ℃ and the time is 30min, and the temperature of the second stage cooling is 4 ℃ and the time is 2 h; and cooling to obtain the PE pipe.

Further, the temperature of the melt blending in the first step and the second step is 200 ℃, and the time is 2 h; the temperature of compression extrusion in the third step is 190 ℃, and the extrusion pressure is 10 MPa.

Furthermore, the split feeding device in the third step is a split plate.

Further, in the fourth step, the inner diameter of the sizing sleeve is 1mm larger than the outer diameter of the PE pipe.

s1, preparing potassium aluminosilicate, washing potassium feldspar through deionized water, crushing, grinding to a particle size smaller than 300 meshes, mixing with a potassium hydroxide aqueous solution with the concentration of 4mol/L, and putting into a high-pressure kettle, wherein the mass of the potassium feldspar is 65g, and the mass of the potassium hydroxide is 26 g; carrying out hydrothermal reaction on potassium feldspar and potassium hydroxide in the high-pressure kettle at the reaction temperature of 180 ℃ for 24 hours; after the reaction is finished, filtering, washing with deionized water and drying to obtain potassium aluminosilicate;

s2, preparing coupled powder I, taking 80g of potassium aluminosilicate, 2g of dispersant, 2g of silane coupling agent and 16g of deionized water, and grinding for 12h by a high-speed wet method until the particle size of the powder reaches 0.5 mu m to obtain the coupled powder I;

s3, preparing coupled powder II, taking 50g of siliceous shale, 20g of waste glass and 10g of fly ash according to weight fraction, grinding the siliceous shale, the waste glass and the fly ash to a particle size of less than 300 meshes, mixing to obtain a raw material mixture I, taking 70g of the raw material mixture I, 2g of a dispersing agent, 60g of palmitic acid, 2g of a silane coupling agent and 15g of deionized water, grinding for 12 hours by a high-speed wet method until the particle size of the powder II reaches 0.5 mu m, and obtaining the coupled powder II;

s4, uniformly mixing 70g of coupled powder I and 30g of coupled powder II, and performing spray drying to obtain the regenerated silica.

Example 3

A high-strength PE pipe comprises an environment-friendly PE inner pipe and a reinforced PE outer pipe, wherein the reinforced PE outer pipe surrounds the outer periphery of the environment-friendly PE inner pipe; the environment-friendly PE inner pipe comprises 70g of high-density polyethylene, 6g of polyolefin elastomer, 10g of nano calcium carbonate whisker, 1g of silane coupling agent and 0.3g of polyethylene wax; the reinforced PE outer pipe comprises 80g of polyethylene, 30g of regenerated silica, 10g of antioxidant, 2g of dispersant, 5g of toughening agent and 5g of paraffin;

Further, the polyolefin elastomer is prepared by copolymerizing ethylene and octene; the antioxidant is triphenyl phosphite; the dispersant is BYK 163; the toughening agent is carboxymethyl cellulose; the silane coupling agent is KH 570.

A preparation method of a high-strength PE pipe comprises the following steps:

step one, respectively taking 70g of high-density polyethylene, 6g of polyolefin elastomer, 10g of nano calcium carbonate whisker and 0.3g of polyethylene wax as silane coupling agent, mixing and stirring uniformly to obtain an inner tube mixed raw material, placing the inner tube mixed raw material in a drying box for drying, then sending the inner tube mixed raw material into a double-screw extruder for melt blending and extrusion to prepare a molten inner tube mixed raw material;

step two, respectively taking 80g of polyethylene, 30g of regenerated silica, 10g of antioxidant, 2g of dispersant, 5g of toughening agent and 5g of paraffin, mixing and stirring uniformly to obtain an outer tube mixed raw material, placing the outer tube mixed raw material in a drying box for drying, and then sending the outer tube mixed raw material into a double-screw extruder for melt blending and extrusion to prepare a molten outer tube mixed raw material;

step four, respectively shaping, cooling in the first stage and cooling in the second stage of the hot tube blank in a vacuum state through a sizing sleeve vacuum sizing box; the temperature of the first stage cooling is-6 ℃ and the time is 30min, and the temperature of the second stage cooling is 9 ℃ and the time is 2 h; and cooling to obtain the PE pipe.

Further, the temperature of the melt blending in the first step and the second step is 220 ℃, and the time is 1 h; the temperature of compression extrusion in the third step is 190 ℃, and the extrusion pressure is 10 MPa.

Further, in the third step, the heat is preserved for 30min before the multilayer co-extrusion die is used.

Furthermore, the split feeding device in the third step is a split plate.

Further, in the fourth step, the inner diameter of the sizing sleeve is 3mm larger than the outer diameter of the PE pipe.

s1, preparing potassium aluminosilicate, washing potassium feldspar through deionized water, crushing, grinding to a particle size smaller than 300 meshes, mixing with a potassium hydroxide aqueous solution with the concentration of 8mol/L, and putting into a high-pressure kettle, wherein the mass of the potassium feldspar is 75g, and the mass of the potassium hydroxide is 35 g; carrying out hydrothermal reaction on potassium feldspar and potassium hydroxide in the high-pressure kettle at the reaction temperature of 180 ℃ for 6 hours; after the reaction is finished, filtering, washing with deionized water and drying to obtain potassium aluminosilicate;

s2, preparing coupled powder I, taking 90g of potassium aluminosilicate, 3g of dispersant, 4g of silane coupling agent and 26g of deionized water, and grinding for 9h by a high-speed wet method until the particle size of the powder reaches 2 microns to obtain the coupled powder I;

s3, preparing coupled powder II, taking 70g of siliceous shale, 30g of waste glass and 20g of fly ash, grinding the siliceous shale, the waste glass and the fly ash to a particle size of less than 300 meshes, mixing to obtain a raw material mixture I, taking 80g of the raw material mixture I, 3g of a dispersing agent, 70g of palmitic acid, 3g of a silane coupling agent and 20g of deionized water, grinding for 9 hours by a high-speed wet method until the particle size of the powder II reaches 2 mu m, and obtaining the coupled powder II;

s4, taking 85g of coupled powder I and 15g of coupled powder II, uniformly mixing, and carrying out spray drying to obtain the regenerated silica.

Comparative example 1

The same components as those of the environment-friendly PE inner pipe in the embodiment 1 are included, wherein the components comprise 65g of high-density polyethylene, 5g of polyolefin elastomer, 8g of nano calcium carbonate whisker, 0.5g of silane coupling agent and 0.2g of polyethylene wax; further, the polyolefin elastomer is prepared by copolymerizing ethylene and octene; the silane coupling agent is KH 550.

The preparation method comprises the following steps:

guiding the inner pipe mixed raw material in a molten state into a die through a shunt feeding device, and performing compression extrusion in the die to obtain a hot pipe blank;

step three, respectively shaping, cooling in the first stage and cooling in the second stage of the hot tube blank in a vacuum state through a sizing sleeve vacuum sizing box; the temperature of the first stage cooling is-12 deg.C, the time is 30min, the temperature of the second stage cooling is 6 deg.C, and the time is 2 h; and cooling to obtain the PE pipe.

Further, the temperature of the melt blending in the first step is 210 ℃, and the time is 1.5 h; the temperature of the compression extrusion in the second step is 180 ℃, and the extrusion pressure is 20 MPa.

Further, the water content of the inner tube mixed raw material dried in the first step is less than 6%.

Further, in the second step, before the mold is used, the temperature is kept for 20 min.

Further, the split feeding device in the second step is a split plate.

Further, in the third step, the inner diameter of the sizing sleeve is 2mm larger than the outer diameter of the PE pipe.

Comparative example 2

The components of the reinforced PE outer pipe are the same as those of the reinforced PE outer pipe in the embodiment 1, and the reinforced PE outer pipe comprises 70g of polyethylene, 15g of regenerated silica, 6g of antioxidant, 1g of dispersing agent, 3g of toughening agent and 3g of paraffin;

Further, the antioxidant is triphenyl phosphite; the dispersant is BYK-110; the toughening agent is carboxymethyl cellulose; the silane coupling agent is KH 550.

The preparation method comprises the following steps:

respectively taking 70g of polyethylene, 15g of regenerated silica, 6g of antioxidant, 1g of dispersant, 3g of toughening agent and 3g of paraffin, mixing and stirring uniformly to obtain an outer tube mixed raw material, placing the outer tube mixed raw material in a drying box for drying, and then sending the outer tube mixed raw material into a double-screw extruder for melt blending and extrusion to prepare a molten outer tube mixed raw material;

guiding the outer pipe mixed raw material in a molten state into a die through a shunt feeding device, and jointly compressing and extruding the mixed raw material in the die to obtain a hot pipe blank;

Further, the water content of the outer tube mixed raw material dried in the first step is less than 6%.

Further, in the second step, before the multilayer co-extrusion die is used, heat preservation is carried out for 20 min.

Further, the split feeding device in the second step is a split plate.

The mechanical properties of the high strength PE pipes prepared in examples 1-3 and the PE pipes of comparative examples 1-2 were measured as follows:

the bending strength is tested according to the GB/T9341-2008 standard;

the tensile strength is tested according to the GB/T1040.1-2006 standard;

the impact strength is tested according to the GB/T1834-2008 standard;

the test results are shown in table 1.

TABLE 1 mechanical Property test results of PE pipes

Group of	Flexural Strength (MPa)	Tensile Strength (MPa)	Impact Strength (KJ/m)²)
				Example 1	68.1	56	11.2
Example 2	67.3	54	10.9
				Example 3	67.6	55	11.0
Comparative example 1	60.1	47	9.1
				Comparative example 2	63.6	49	9.9

From the table 1 content it can be seen that the pipes of the single layers of comparative example 1 and comparative example 2 have lower bending strength and lower tensile and impact strength. The bending strength, tensile strength and impact strength of the examples 1-3 are all improved remarkably, which shows that the PE pipes of the examples 1-3 have high strength.

Claims

1. A high-strength PE pipe is characterized in that: the reinforced PE pipe comprises an environment-friendly PE inner pipe and a reinforced PE outer pipe, wherein the reinforced PE outer pipe surrounds the outer periphery of the environment-friendly PE inner pipe; the environment-friendly PE inner pipe comprises, by weight, 60-70 parts of high-density polyethylene, 3-6 parts of a polyolefin elastomer, 6-10 parts of nano calcium carbonate whiskers, 0.2-1 part of a silane coupling agent and 0.1-0.3 part of polyethylene wax; the reinforced PE outer pipe comprises, by weight, 60-80 parts of polyethylene, 5-30 parts of regenerated silica, 2-10 parts of an antioxidant, 0.5-2 parts of a dispersant, 0.5-5 parts of a toughening agent and 0.5-5 parts of paraffin;

2. A high strength PE pipe according to claim 1, wherein: the polyolefin elastomer is prepared by copolymerizing ethylene and octene; the antioxidant is one of triphenyl phosphite, calcium stearate and tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester; the dispersing agent is one of BYK-110, FS-5118 or BYK 163; the toughening agent is one of carboxymethyl cellulose, polyolefin elastomer or ethylene propylene diene monomer; the silane coupling agent comprises at least one of KH550, KH560 and KH 570.

3. The method for preparing a high-strength PE pipe material according to claim 1, wherein the method comprises the following steps: the method comprises the following steps:

4. A method of making a high strength PE pipe according to claim 3, wherein: the temperature of the melt blending in the first step and the second step is 200-220 ℃, and the time is 1-2 h; the temperature of the compression extrusion in the third step is 180-190 ℃, and the extrusion pressure is 10-20 MPa.

5. A method of making a high strength PE pipe according to claim 3, wherein: the water content of the inner tube mixed raw material dried in the step one and the water content of the outer tube mixed raw material dried in the step two are less than 6%.

6. A method of making a high strength PE pipe according to claim 3, wherein: in the third step, the heat is preserved for 20-30 min before the multilayer co-extrusion die is used.

7. A method of making a high strength PE pipe according to claim 3, wherein: and the flow dividing and feeding equipment in the third step is a flow dividing plate.

8. A method of making a high strength PE pipe according to claim 3, wherein: in the fourth step, the inner diameter of the sizing sleeve is 1-3 mm larger than the outer diameter of the PE pipe.

9. A method of making a high strength PE pipe according to claim 3, wherein: the preparation method of the regenerated silica comprises the following steps: