1. A laying pipe is prepared by casting a mesh cage and a composite sizing material, and is characterized in that the composite sizing material comprises the following raw materials:

modified polypropylene particles, polyethylene particles, butyl rubber powder, an antioxidant, a nucleating agent and a leveling agent;

the modified polypropylene particles are prepared by the following steps:

step A1: mixing allyl chloride and phosphoric acid, adding into a reactor, adding absolute ethyl alcohol and potassium iodide, heating in water bath to 32-37 ℃ under the protection of nitrogen, stirring for reaction for 3-5h, introducing ammonia gas to adjust the pH value of the reaction solution to 6-7, separating liquid, taking an organic phase, removing the absolute ethyl alcohol, and preparing a polymerization monomer;

step A2: adding a polymerization monomer and acetone into a reactor, adding azodiisobutyronitrile, stirring and reacting for 2-3h at room temperature under sealing, and then stirring in a ventilating way to obtain modified polypropylene resin;

step A3: the modified polypropylene resin and the plasticizer DOP are mixed and plasticated, and then extruded and granulated to prepare modified polypropylene particles.

2. The laying pipe according to claim 1, wherein in step A1, the ratio of the amounts of allyl chloride, phosphoric acid, absolute ethyl alcohol and potassium iodide is 1 mol: 1.1-1.3 mol: 8-12 mL: 1.3-1.7 g.

3. The laying pipe according to claim 1, wherein in step A2, the ratio of the amount of the polymerization monomer, the acetone and the azobisisobutyronitrile is 15 mL: 20mL of: 0.4-0.6 g.

4. The laying pipe according to claim 1, wherein the modified polypropylene particles and the plasticizer DOP are used in a mass ratio of 100:1.2-1.5 in the step A3.

5. The laying pipe according to claim 1, wherein in the step A3, the modified polypropylene resin is filtered by a 50-mesh screen before use.

6. The laying pipe according to claim 1, wherein the mixing and plastication temperature in step A3 is 160-180 ℃, and the plastication time is 2-3 h.

7. Process for the production of a laying pipe according to claim 1, characterized by the following steps:

preparing a mesh cage: adopting steel wires to form a net cage, setting the density of the steel wires of the inner ring to be 1.8-2.2 cm/piece, the density of the steel wires of the outer ring to be 3.5-4 cm/piece, welding and connecting the steel wires of the inner ring and the outer ring through the steel wires, and setting the density of the steel wires to be 10-12 cm/piece;

and (3) cylinder mould treatment: alkali washing the net cage with sodium carbonate solution at 40-50 deg.c, washing with dilute sulfuric acid after washing with tap water, washing with tap water again, and air drying;

preparing a composite sizing material: banburying modified polypropylene particles, polyethylene particles, butyl rubber powder and an antioxidant at the temperature of 190-;

and (3) casting molding: preheating the mould to 80-100 ℃, placing the mesh cage into the mould for positioning, extruding the composite sizing material into the mould, cooling for forming, and trimming to obtain the laying pipe.

8. The laying pipe according to claim 1, wherein the raw materials of the composite sizing comprise, by weight: 65-80 parts of modified polypropylene particles, 45-60 parts of polyethylene particles, 12-20 parts of butyl rubber powder, 1.8-2.1 parts of antioxidant, 0.4-0.6 part of nucleating agent and 3.5-5 parts of leveling agent.

Background

In industrial and civil engineering, various fluids or gases are mostly conveyed by pipelines, so that various pipes exist in the prior art, plastic pipes are favored due to good impermeability, corrosion resistance and easy forming, are commonly used for conveying acid, alkali, steam and the like, cement pipes are strong in pressure bearing capacity, long in service life and low in price, and are commonly used in water supply and drainage engineering construction.

In the prior art, a steel-plastic composite pipe is also provided, the pipe is made of a steel plate into a base pipe, and a plastic sizing material is sprayed on the surface of the base pipe, but the bonding strength of the plastic sizing material and the steel plate is not high, the plastic layer and the steel plate layer are easy to peel off under the repeated compression working condition, and the service life is not long.

Disclosure of Invention

In order to overcome the technical problems mentioned in the technical background, the invention aims to provide a laying pipe and a preparation process thereof.

The purpose of the invention can be realized by the following technical scheme:

the laying pipe is prepared by casting a cylinder mould and a composite sizing material, wherein the composite sizing material comprises the following raw materials in parts by weight:

65-80 parts of modified polypropylene particles, 45-60 parts of polyethylene particles, 12-20 parts of butyl rubber powder, 1.8-2.1 parts of antioxidant, 0.4-0.6 part of nucleating agent and 3.5-5 parts of flatting agent;

the modified polypropylene particles are prepared by the following steps:

step A1: mixing allyl chloride and phosphoric acid, adding the mixture into a reactor, adding absolute ethyl alcohol and potassium iodide into the reactor, discharging air in the reactor by using nitrogen, heating the mixture in a water bath at 32-37 ℃, controlling the stirring speed to be 180-one (r/min), reacting for 3-5h, introducing ammonia into the reaction liquid until the pH of the reaction liquid is 6-7, standing for liquid separation, taking a lower-layer liquid phase, stirring for 5-8h at room temperature, and volatilizing the absolute ethyl alcohol in the reaction liquid to obtain a polymeric monomer;

the specific reaction process is as follows:

step A2: adding a polymerization monomer and acetone into a reactor, adding azodiisobutyronitrile, sealing the reactor, controlling the stirring speed to be 200-250r/min at room temperature, reacting for 2-3h, then reducing the stirring speed to be 40-60r/min under the condition of ventilation of the reactor, and continuously stirring for 8-10h to obtain the modified polypropylene resin;

the specific reaction process is as follows:

step A3: adding the modified polypropylene resin and the plasticizer DOP into open plasticating equipment, controlling the plasticating temperature at 160-180 ℃, plasticating for 2-3h, and then extruding and granulating to prepare modified polypropylene particles.

Further, in step a1, allyl chloride, phosphoric acid, absolute ethanol, and potassium iodide are used in a ratio of 1 mol: 1.1-1.3 mol: 8-12 mL: 1.3-1.7 g.

Further, in step a2, the ratio of the amount of the polymerization monomers, acetone and azobisisobutyronitrile used is 15 mL: 20mL of: 0.4-0.6 g.

Further, in the step A3, the modified polypropylene particles and the plasticizer DOP are used in a mass ratio of 100:1.2-1.5, and the modified polypropylene resin is filtered by a 50-mesh screen before use.

Further, the antioxidant is bisphenol A.

Further, the nucleating agent is a nucleating agent DX-Z3C.

Further, the leveling agent is a leveling agent BYK-358N.

A preparation process of a laying pipe comprises the following steps:

preparing a mesh cage: adopting steel wires to form a net cage, setting the density of the steel wires of the inner ring to be 1.8-2.2 cm/piece, the density of the steel wires of the outer ring to be 3.5-4 cm/piece, welding and connecting the steel wires of the inner ring and the outer ring through the steel wires, and setting the density of the steel wires to be 10-12 cm/piece;

and (3) cylinder mould treatment: placing the net cage in sodium carbonate solution, cleaning at 40-50 deg.C for 10-15min, washing the net cage with tap water for 1-2 times, soaking the net cage in dilute sulfuric acid for 8-10min, washing with tap water for 1-2 times, and air drying;

preparing a composite sizing material: according to the weight part modification, adding polypropylene particles, polyethylene particles, butyl rubber powder and an antioxidant into an internal mixer, controlling the temperature at 190-;

and (3) casting molding: preheating the mould to 80-100 ℃, placing the mesh cage into the mould for positioning, extruding the composite sizing material into the mould, cooling for forming, and trimming to obtain the laying pipe.

The invention has the beneficial effects that:

the invention prepares a modified polypropylene particle in the process of preparing laying pipes, which takes allyl chloride and phosphoric acid as raw materials, generates substitution reaction under the catalysis of potassium iodide to generate a polymeric monomer containing double bonds and phosphate groups, then generates polyaddition reaction under the catalysis of azodiisobutyronitrile by the polymeric monomer to generate polypropylene resin with side chains containing phosphate groups, and finally plasticizes and granulates the resin, the phosphorus hydroxyl on the phosphate groups on the side chains of the modified polypropylene particle has stronger chelation with the metal surface and can react with polyvalent metals to form phosphate complexes to form a layer of compact phosphating film, firstly, the polymer is firmly connected to the metal base material in a covalent bond form to form a bridge between the polymer and the metal base material, thereby improving the bonding force of the sizing material and the metals, solving the problem of peeling of the sizing material layer, and secondly, the compact phosphating film can passivate the surface of the metal base material to prevent the surface from rusting, greatly prolonging the service life of the pipe.

The laying pipe provided by the invention is prepared by casting the mesh cage and the composite sizing material, the steel wire mesh cage is used as a framework, the supporting and restoring effects are realized when the steel wire mesh cage is stressed, the good compression resistance and tensile resistance are realized, the mesh cage is subjected to alkali washing and acid washing treatment, surface impurities are removed, phosphate groups can better react with a metal base material to obtain chemical bonds, on the other hand, the surface of the steel wire is roughened, the bonding sites of the sizing material and the steel wire are increased, the bonding force is further improved, and the impermeability of the sizing material is further improved by filling butyl rubber powder added in the raw material of the composite sizing material in the sizing material.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the examples:

the antioxidant adopts bisphenol A.

The nucleating agent adopts a nucleating agent DX-Z3C.

And the leveling agent is a leveling agent BYK-358N.

The mass fraction of the sodium carbonate solution is 5%.

The mass fraction of the dilute sulfuric acid is 8 percent.

Example 1

In this example, a modified polypropylene particle is prepared by the following specific steps:

step A1: mixing allyl chloride and phosphoric acid, adding the mixture into a reactor, adding absolute ethyl alcohol and potassium iodide into the reactor, filling nitrogen into the reactor to discharge air in the reactor, heating the mixture in a water bath at 32 ℃, controlling the stirring speed to be 180r/min, reacting for 3 hours, then introducing ammonia gas into the reaction liquid until the pH of the reaction liquid is 6, standing and separating the liquid, taking the lower layer liquid phase, stirring the lower layer liquid phase for 5 hours at room temperature, volatilizing the absolute ethyl alcohol in the reaction liquid to prepare a polymeric monomer, wherein the dosage ratio of the allyl chloride, the phosphoric acid, the absolute ethyl alcohol and the potassium iodide is 1 mol: 1.1 mol: 8mL of: 1.3 g;

step A2: adding a polymerization monomer and acetone into a reactor, adding azobisisobutyronitrile, sealing the reactor, controlling the stirring speed at 200r/min at room temperature, reacting for 2 hours, then reducing the stirring speed at 40r/min under the condition of introducing air into the reactor, and continuously stirring for 8 hours to obtain the modified polypropylene resin, wherein the dosage ratio of the polymerization monomer to the acetone to the azobisisobutyronitrile is 15 mL: 20mL of: 0.4 g;

step A3: adding the modified polypropylene resin and the plasticizer DOP into open plastic equipment, controlling the plastication temperature at 160 ℃, plasticating for 2h, then extruding and granulating to prepare modified polypropylene particles, wherein the mass ratio of the modified polypropylene particles to the plasticizer DOP is 100:1.2, and the modified polypropylene particles are filtered by a 50-mesh screen before use.

Example 2

In this example, a modified polypropylene particle is prepared by the following specific steps:

step A1: mixing allyl chloride and phosphoric acid, adding the mixture into a reactor, adding absolute ethyl alcohol and potassium iodide into the reactor, filling nitrogen into the reactor to discharge air in the reactor, heating the mixture in a water bath at 35 ℃, controlling the stirring speed to be 200r/min, reacting for 4 hours, introducing ammonia gas into reaction liquid until the pH of the reaction liquid is 7, standing and separating the liquid, taking a lower-layer liquid phase, stirring the lower-layer liquid phase for 7 hours at room temperature, and volatilizing the absolute ethyl alcohol in the reaction liquid to prepare a polymeric monomer, wherein the dosage ratio of the allyl chloride, the phosphoric acid, the absolute ethyl alcohol and the potassium iodide is 1 mol: 1.2 mol: 10mL of: 1.5 g;

step A2: adding a polymerization monomer and acetone into a reactor, adding azobisisobutyronitrile, sealing the reactor, controlling the stirring speed at 200r/min at room temperature, reacting for 2 hours, then reducing the stirring speed at 50r/min under the condition of introducing air into the reactor, and continuously stirring for 9 hours to obtain the modified polypropylene resin, wherein the dosage ratio of the polymerization monomer to the acetone to the azobisisobutyronitrile is 15 mL: 20mL of: 0.5 g;

step A3: adding the modified polypropylene resin and the plasticizer DOP into open plastic equipment, controlling the plastication temperature at 170 ℃, plasticating for 2h, then extruding and granulating to prepare modified polypropylene particles, wherein the mass ratio of the modified polypropylene particles to the plasticizer DOP is 100:1.4, and the modified polypropylene particles are filtered by a 50-mesh screen before use.

Example 3

In this example, a modified polypropylene particle is prepared by the following specific steps:

step A1: mixing allyl chloride and phosphoric acid, adding the mixture into a reactor, adding absolute ethyl alcohol and potassium iodide into the reactor, filling nitrogen into the reactor to discharge air in the reactor, heating the mixture in a water bath at 37 ℃, controlling the stirring speed to be 240r/min, reacting for 5 hours, introducing ammonia gas into the reaction liquid until the pH of the reaction liquid is 7, standing and separating the liquid, taking the lower layer liquid phase, stirring the lower layer liquid phase for 8 hours at room temperature, volatilizing the absolute ethyl alcohol in the reaction liquid to prepare a polymeric monomer, wherein the dosage ratio of the allyl chloride, the phosphoric acid, the absolute ethyl alcohol and the potassium iodide is 1 mol: 1.3 mol: 12mL of: 1.7 g;

step A2: adding a polymerization monomer and acetone into a reactor, adding azobisisobutyronitrile, sealing the reactor, controlling the stirring speed to be 250r/min at room temperature, reacting for 3 hours, then reducing the stirring speed to be 60r/min under the condition of introducing air into the reactor, and continuously stirring for 10 hours to obtain the modified polypropylene resin, wherein the dosage ratio of the polymerization monomer to the acetone to the azobisisobutyronitrile is 15 mL: 20mL of: 0.6 g;

step A3: adding the modified polypropylene resin and the plasticizer DOP into open plastic equipment, controlling the plastication temperature at 180 ℃, plasticating for 3h, then extruding and granulating to prepare modified polypropylene particles, wherein the mass ratio of the modified polypropylene particles to the plasticizer DOP is 100:1.5, and the modified polypropylene particles are filtered by a 50-mesh screen before use.

Example 4

The preparation method of the laying pipe comprises the following raw materials in parts by weight:

65 parts of modified polypropylene particles, 45 parts of polyethylene particles prepared in example 1, 12 parts of butyl rubber powder, 1.8 parts of antioxidant, 0.4 part of nucleating agent and 3.5 parts of leveling agent;

the preparation process comprises the following steps:

preparing a mesh cage: adopting steel wires to form a net cage, setting the density of the steel wires of the inner ring to be 1.8 cm/piece, setting the density of the steel wires of the outer ring to be 3.5 cm/piece, welding and connecting the steel wires of the inner ring and the outer ring through the steel wires, and setting the density of the steel wires to be 10 cm/piece;

and (3) cylinder mould treatment: placing the net cage in sodium carbonate solution, cleaning at 40 deg.C for 10min, washing the net cage with tap water for 1 time, soaking the net cage in dilute sulfuric acid for 8min, washing with tap water for 1 time, and air drying;

preparing a composite sizing material: adding the modified polypropylene particles, the polyethylene particles, the butyl rubber powder and the antioxidant in parts by weight into an internal mixer, controlling the temperature at 190 ℃ and carrying out internal mixing treatment at the stirring speed of 200r/min for 30min, then adding the nucleating agent, the defoaming agent and the leveling agent into the internal mixer, stirring for 10min, extruding the mixed material by a screw extruder, and setting the discharging temperature at 140 ℃ to prepare a composite rubber material;

and (3) casting molding: preheating the mould to 80 ℃, placing the mesh cage into the mould for positioning, extruding the composite sizing material into the mould, cooling for forming, and trimming to obtain the laying pipe.

Example 5

The preparation method of the laying pipe comprises the following raw materials in parts by weight:

70 parts of modified polypropylene particles, 50 parts of polyethylene particles prepared in example 2, 15 parts of butyl rubber powder, 2 parts of antioxidant, 0.5 part of nucleating agent and 4 parts of leveling agent;

the preparation process comprises the following steps:

preparing a mesh cage: adopting steel wires to form a net cage, setting the density of the steel wires of the inner ring to be 2 cm/piece, setting the density of the steel wires of the outer ring to be 3.8 cm/piece, welding and connecting the steel wires of the inner ring and the outer ring through the steel wires, and setting the density of the steel wires to be 11 cm/piece;

and (3) cylinder mould treatment: placing the net cage in sodium carbonate solution, cleaning at 45 deg.C for 12min, washing with tap water for 2 times, soaking in dilute sulfuric acid for 9min, washing with tap water for 2 times, and air drying;

preparing a composite sizing material: adding the modified polypropylene particles, the polyethylene particles, the butyl rubber powder and the antioxidant in parts by weight into an internal mixer, controlling the temperature to be 200 ℃, carrying out internal mixing treatment at the stirring speed of 200r/min for 25min, then adding the nucleating agent, the defoaming agent and the leveling agent into the internal mixer, stirring for 8min, extruding the mixed material by a screw extruder, and setting the discharging temperature to be 145 ℃ to prepare a composite rubber material;

and (3) casting molding: preheating the mould to 90 ℃, placing the mesh cage into the mould for positioning, extruding the composite sizing material into the mould, cooling for forming, and trimming to obtain the laying pipe.

Example 6

The preparation method of the laying pipe comprises the following raw materials in parts by weight:

80 parts of modified polypropylene particles, 60 parts of polyethylene particles prepared in example 3, 20 parts of butyl rubber powder, 2.1 parts of antioxidant, 0.6 part of nucleating agent and 5 parts of leveling agent;

the preparation process comprises the following steps:

preparing a mesh cage: adopting steel wires to form a net cage, setting the density of the steel wires of the inner ring to be 2.2 cm/piece, setting the density of the steel wires of the outer ring to be 4 cm/piece, welding and connecting the steel wires of the inner ring and the outer ring through the steel wires, and setting the density of the steel wires to be 12 cm/piece;

and (3) cylinder mould treatment: placing the net cage in sodium carbonate solution, cleaning at 50 deg.C for 15min, washing the net cage with tap water for 2 times, soaking the net cage in dilute sulfuric acid for 10min, washing with tap water for 2 times, and air drying;

preparing a composite sizing material: adding the modified polypropylene particles, the polyethylene particles, the butyl rubber powder and the antioxidant in parts by weight into an internal mixer, controlling the temperature at 210 ℃, carrying out internal mixing treatment at the stirring speed of 300r/min for 20min, then adding the nucleating agent, the defoaming agent and the leveling agent into the internal mixer, stirring for 5min, extruding the mixed material by a screw extruder, and setting the discharge temperature at 150 ℃ to prepare a composite rubber material;

and (3) casting molding: preheating a mould to 100 ℃, placing the mesh cage into the mould for positioning, extruding the composite sizing material into the mould, cooling for forming, and trimming to obtain the laying pipe.

Comparative example 1

This comparative example is a commercial PVC pipe.

Comparative example 2

The comparative example is a commercial cement pipe.

Comparative example 3

This comparative example is a commercially available steel-plastic composite pipe.

The samples prepared in examples 4-6 and comparative examples 1-3 were tested for their properties, as follows:

examples 4 to 6, comparative example 1 and comparative example 3 were subjected to an internal pressure resistance test in accordance with GB/T6111-:

TABLE 1

As can be seen from Table 1, the pipes prepared in examples 4-6 have excellent internal pressure resistance, wherein example 5 reaches 15.5MPa, and can be used for high-pressure medium transportation.

Taking examples 4-6 and comparative example 2, filling tap water of 3MPa into the interior after end capping, observing the surface water seepage condition, recording the surface water seepage days, and the specific data are shown in Table 2:

TABLE 2

	20d	30d	40d	50d
					Example 4	Without water seepage	Without water seepage	Without water seepage	Without water seepage
Example 5	Without water seepage	Without water seepage	Without water seepage	Without water seepage
					Example 6	Without water seepage	Without water seepage	Without water seepage	Without water seepage
Comparative example 2	Without water seepage	Without water seepage	Without water seepage	Surface water seepage

As can be seen from Table 2, the pipes obtained in examples 4 to 6 have good barrier properties and show no leakage at a water pressure of 3MPa for 50 days.

The radial compression test was performed in the hydraulic press using examples 4 to 6 and comparative examples 1 to 3, and the specific data are shown in Table 3:

TABLE 3

	30MPa	60MPa	90MPa	100MPa
					Example 4	0.35％	0.87％	25.35％	57.85％
Example 5	0.27％	0.67％	21.65％	49.78％
					Example 6	0.43％	1.12％	33.98％	61.45％
Comparative example 1	9.45％	Completely flattened	/	/
					Comparative example 2	Without deformation	Without deformation	Collapse	/
Comparative example 3	2.78％	8.52％	43.75	Completely flattened

As shown in Table 3, in example 5, the radial deformation rate is 21.65% under the pressure of 90MPa, the pipe in comparative example 1 is completely flattened, the cement pipe in comparative example 2 is collapsed, the radial deformation rate in comparative example 3 is 43.75%, and the pipe prepared by the method has good compression resistance.

Examples 4-6 and comparative example 3 were placed on a hydraulic press and pressed down radially at 30MPa repeatedly to record the number of visible flaking off of the cement layer from the substrate, as specified in table 4:

TABLE 4

	Example 4	Example 5	Example 6	Comparative example 3
					Number of times	277	293	245	122

As can be seen from table 4, the number of times of pressing in examples 4-6 is much greater than that in comparative example 3, wherein example 5 is as high as 293, the binding ability of the sizing material and the base material is strong, and the sizing material and the base material are not easy to peel off, because the phosphorus hydroxyl group on the phosphate group on the side chain of the added modified polypropylene particle has a strong chelating effect with the metal surface, and can react with the polyvalent metal to form a phosphate complex, thereby forming a layer of compact phosphate film, the polymer is firmly connected to the metal base material in the form of covalent bond to form a bridge between the polymer and the metal base material, and the mesh cage is subjected to alkali washing and acid washing treatment to remove surface impurities, so that the phosphate group better reacts with the metal base material to obtain chemical bond, and on the other hand, the surface of the steel wire is roughened, the binding sites of the sizing material and the steel wire are increased, the binding force is further improved, and the sizing material has excellent anti-peeling performance.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is illustrative and explanatory only and is not intended to be exhaustive or to limit the invention to the precise embodiments described, and various modifications, additions, and substitutions may be made by those skilled in the art without departing from the scope of the invention or exceeding the scope of the claims.