Preparation method of steel wire mesh composite polyethylene pipe

Abstract

The invention provides a preparation method of a steel wire mesh composite polyethylene pipe, which relates to the field of polyethylene pipe manufacturing. The steel wire mesh composite polyethylene pipe comprises a polyethylene outer pipe layer, a polyethylene inner pipe layer, a steel wire mesh and a double-layer adhesive film, wherein the double-layer adhesive film sandwiches the steel wire mesh, and raw material components of the polyethylene outer pipe layer comprise high-density polyethylene, benzoyl peroxide, an anti-corrosion agent, an antioxidant, carboxymethyl cellulose and polyethylene wax; raw material components of the polyethylene inner pipe layer comprise high-density polyethylene, acrylonitrile-butadiene-styrene copolymer, a toughening agent and polyethylene wax; raw material components of the double-layer adhesive film comprise a polyurethane resin containing multiple hydroxyl points on the surface, an SMA resin-modified polyethylene-ester copolymer, a phytic acid-modified polyvinyl alcohol resin, an initiator and a crosslinking agent. The invention as a whole has the advantages of good pressure resistance, good bonding effect between the polyethylene pipe material and the steel wire mesh, and good mechanical properties.

Description

Technical Field

[0001] The invention relates to the field of polyethylene pipe manufacturing, and specifically provides a method for preparing a steel wire mesh composite polyethylene pipe. Background Art

[0002] Steel mesh composite polyethylene pipe, also known as steel mesh skeleton polyethylene composite pipe, is a new type of composite pipe. It features a reinforced framework of high-strength steel wire, with outer and inner polyethylene layers, interposed with a multi-layer steel mesh reinforcement layer. The outer steel wire layer is coated with a hot-melt adhesive and water-blocking coating. This pipe combines the strength of steel mesh with the corrosion resistance and flexibility of polyethylene, resulting in excellent performance. Its unique compressive strength makes it suitable for specialized applications such as fire water supply, a requirement that places significant demands on the performance of steel mesh composite polyethylene pipe.

[0003] Since the pressure resistance requirement for fire water supply pipelines is to be able to maintain a pressure of 1.20MPa for a long time, and under special requirements, it must be able to maintain a working pressure of 1.60MPa for a shorter period of time, this is also a higher standard for steel mesh composite polyethylene pipes. The inner and outer pipe layers of common steel mesh composite polyethylene pipes are made of the same material. Although the consistency of the pipe is guaranteed, it also causes the inner pipe layer to be unable to withstand higher intensity pressure. After the working pressure increases instantly, if cracks appear in the inner pipe layer, this consistency will also cause the pipe to be quickly damaged.

[0004] In addition, common steel mesh composite polyethylene pipes usually adopt the method of setting adhesive resin on the outside of the steel mesh layer to enhance the cross-linking effect between the steel mesh and the inner and outer polyethylene pipe layers, thereby improving the overall performance of the steel mesh composite polyethylene pipe. However, the properties of the adhesive resin and polyethylene are different after all. The thicker the adhesive resin, the more negative impact it will have on the structural stability of the steel mesh composite polyethylene pipe. Conventional adhesive resins with low thickness cannot achieve a good bonding effect between the steel mesh and the inner and outer polyethylene pipe layers. At the same time, the process of applying the adhesive resin is generally after winding the steel mesh. At this time, the operating space around the pipe material is relatively narrow, the coating process is extremely cumbersome, and the operation is difficult.

[0005] Published patent CN115195168A discloses a wire mesh skeleton composite pipe and its production method. This solution provides a hot melt adhesive layer between the inner polyethylene layer and the outer polyethylene layer. At the same time, the raw material components of the inner polyethylene tube layer and the outer polyethylene tube layer are the same. If it is used in a fire water supply pipe, it will not be able to sustain a working pressure of up to 1.60 MPa for a long time. Once the inner polyethylene layer is damaged, the hot melt adhesive layer and the wire mesh layer will be peeled off by the water pressure in a short time, and the entire pipe will collapse extremely quickly. Summary of the Invention

[0006] In view of the above defects in the prior art, the present invention provides a method for preparing a steel wire mesh composite polyethylene pipe, which solves the problem of enhancing the compressive strength of the steel wire mesh composite polyethylene pipe and the bonding effect between the steel wire mesh and the polyethylene pipe material.

[0007] The objective of the present invention is achieved through the following technical solution: the steel wire mesh composite polyethylene pipe is composed of a polyethylene outer tube layer, a polyethylene inner tube layer, a steel wire mesh and a double-layer adhesive film, the double-layer adhesive film sandwiching the steel wire mesh, the raw material components of the polyethylene outer tube layer include high-density polyethylene, benzoyl peroxide, an anti-corrosion agent, an antioxidant, carboxymethyl cellulose, and polyethylene wax, the raw material components of the polyethylene inner tube layer include high-density polyethylene, acrylonitrile-butadiene-styrene copolymer, a toughening agent, and polyethylene wax, and the raw material components of the double-layer adhesive film include a polyurethane resin having multiple hydroxyl points on the surface, an SMA resin-modified polyethylene-ester copolymer, a phytic acid-modified polyvinyl alcohol resin, an initiator, and a cross-linking agent;

[0008] The anti-corrosion agent is selected from one or more of glucosinolate, bisphenol A epoxy resin and EVA resin;

[0009] The antioxidant is selected from one or more of tris(nonylphenol) phosphite, triphenyl phosphite and 2,6-di-tert-butyl-4-methylphenol;

[0010] The toughening agent is selected from one or more of thermoplastic elastomer SBS, high-density polyethylene fiber and nano boron fiber;

[0011] The initiator is selected from one or more of dibenzoyl peroxide, tert-butyl peroxide 3,5,5-trimethylhexanoate, tert-amyl peroxybenzoate, and tert-butyl peroxide 2-ethylhexyl carbonate;

[0012] The cross-linking agent is selected from one or more of trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, and pentaerythritol triacrylate;

[0013] The preparation method of the steel wire mesh composite polyethylene pipe comprises the following steps:

[0014] S1: High-density polyethylene and acrylonitrile-butadiene-styrene copolymer are uniformly mixed and then fed into a melting device for melting. A toughening agent is added after the high-density polyethylene becomes a melt state. After all the high-density polyethylene is melted, polyethylene wax is added. The polyethylene is extruded through a twin-screw extruder, and after being shaped by a mold, a core tube is formed and then sized. Before the core tube enters the sizing sleeve, it is cooled in advance by spraying, and the sizing sleeve is cooled. After sizing, the polyethylene inner tube layer is obtained;

[0015] S2: The polyethylene inner tube layer is fed into the steel wire winding equipment through a traction machine. A layer of adhesive film is first covered on the outer surface of the polyethylene inner tube layer. Steel wires are woven into a mesh on the surface of the polyethylene inner tube layer to form a steel mesh. Then, another layer of adhesive film is covered. The adhesive film is heated until it is semi-molten and pressure is applied to adhere the double-layer adhesive film to the polyethylene inner tube layer and the steel mesh.

[0016] S3: High-density polyethylene is sent to a melting device for melting. After the high-density polyethylene becomes a melt state, evenly mixed benzoyl peroxide, anti-corrosion agent, and antioxidant are added, and the mixture is stirred while being kept warm. After cooling down by 20°C, carboxymethyl cellulose and polyethylene wax are added, and the mixture is sent to a twin-screw extruder for extrusion and coating on the outer surface of a double-layer adhesive film to form a polyethylene outer tube layer. After cooling, a steel wire mesh skeleton composite tube is obtained.

[0017] In the above-mentioned method for preparing a steel wire mesh composite polyethylene pipe, preferably, the double-layer adhesive film is prepared by:

[0018] T1: SMA resin modified polyethylene-ester copolymer, polyurethane resin containing multiple hydroxyl points on the surface, and initiator are first mixed and sent to a melting device for melting. After the SMA resin modified polyethylene-ester copolymer becomes a melt, phytic acid modified polyvinyl alcohol resin and a cross-linking agent are added. After all are melted, they are sent to an extruder for extrusion and granulation to obtain adhesive particles;

[0019] T2: Feed the adhesive particles into the casting equipment and set the casting temperature to 85~110℃. After the casting is completed, a film sheet, i.e., an adhesive film, is obtained.

[0020] In the above-mentioned method for preparing a steel wire mesh composite polyethylene pipe, preferably, the preparation method of the SMA resin-modified polyethylene-ester copolymer is: mixing the polyethylene-ester copolymer with dry magnesium hydroxide powder and then performing a melt reaction, adding an unsaturated SMA resin and an initiator after the melting is completed to perform a melt grafting reaction, grafting the SMA resin onto the polyethylene-ester copolymer molecular chain through the unsaturated bonds in the unsaturated SMA resin, and extruding and granulating to obtain the unsaturated SMA resin-modified polypropylene;

[0021] Furthermore, the polyethylene-ester copolymer is selected from one or more of polyethylene-vinyl acetate copolymer, polyethylene-methyl acrylate copolymer, polyethylene-ethyl acrylate copolymer and polyethylene-butyl acrylate copolymer;

[0022] Furthermore, the mass ratio of polyethylene-ester copolymer to unsaturated SMA resin is 1:0.5~1; the mass ratio of polyethylene-ester copolymer to magnesium hydroxide powder is 1:0.8~1; the temperature of the melt reaction is 140~180°C, and the temperature of the melt grafting reaction is 160~210°C; the initiator is added to the melting equipment in batches, with a single interval of 2 minutes, and the amount added in a single batch is 1 / 5 of the total amount of initiator.

[0023] In the above-mentioned method for preparing a steel wire mesh composite polyethylene pipe, preferably, the SMA resin is prepared by: after the SMA resin is completely melted, an unsaturated compound containing a double bond is added dropwise, and after the reaction is completed, an unsaturated SMA resin is obtained;

[0024] Furthermore, the unsaturated compound is selected from one or more of propylene glycol, methyl propylene glycol, maleic acid hydrazide, and acrylamide; the mass ratio of SMA resin to unsaturated compound is 1:0.1~0.2; the reaction temperature is 150~190°C, and the reaction time is 1.5~2h.

[0025] In the above-mentioned method for preparing a steel wire mesh composite polyethylene pipe, preferably, the polyurethane resin having a plurality of hydroxyl sites on the surface is prepared by reacting diethylene oxide with carbon dioxide in the presence of a catalyst to generate an intermediate product, and then reacting the intermediate product with diethylenetriamine to generate the polyurethane resin having a plurality of hydroxyl sites on the surface;

[0026] Furthermore, the catalyst is selected from one or more of lithium chloride, sodium bromide, and sodium iodide, the mass ratio of dioxirane to catalyst is 1:0.05~0.15, the reaction temperature is 90~160°C, and the reaction solvent is selected from one or more of N,N-dimethylformamide, methanol, and tetrahydrofuran.

[0027] In the above-mentioned method for preparing a steel mesh composite polyethylene pipe, preferably, the method for preparing the phytic acid modified polyvinyl alcohol resin is: dissolving polyvinyl alcohol in a solution, adding phytic acid and sulfuric acid to catalyze an esterification reaction, and washing the product with water and centrifuging and drying to obtain the phytic acid modified polyvinyl alcohol resin.

[0028] In the above-mentioned method for preparing a steel wire mesh composite polyethylene pipe, preferably, the raw materials of the polyethylene outer tube layer are 100 parts by weight of high-density polyethylene, 15-20 parts by weight of benzoyl peroxide, 7-10 parts by weight of corrosion inhibitor, 5-8 parts by weight of antioxidant, 3-5 parts by weight of carboxymethyl cellulose, and 4 parts by weight of polyethylene wax.

[0029] In the above-mentioned method for preparing a steel wire mesh composite polyethylene pipe, preferably, the raw materials of the polyethylene inner tube layer are 100 parts by weight of high-density polyethylene, 18-25 parts by weight of acrylonitrile-butadiene-styrene copolymer, 10-15 parts by weight of toughener, and 4 parts by weight of polyethylene wax.

[0030] In the above-mentioned method for preparing a steel wire mesh composite polyethylene pipe, preferably, the raw materials of the double-layer adhesive film are 100 parts by weight of SMA resin-modified polyethylene-ester copolymer, 20 to 35 parts of polyurethane resin containing multiple hydroxyl points on the surface, 15 to 20 parts of phytic acid-modified polyvinyl alcohol resin, 3 to 6 parts of initiator, and 5 to 10 parts of cross-linking agent.

[0031] In the above-mentioned method for preparing a steel wire mesh composite polyethylene pipe, preferably, in step S2, the steel wires are subjected to a surface treatment process before being woven into a steel wire mesh, and the surface treatment comprises the following steps:

[0032] E1 Degreasing: Immerse the steel wire in an alkaline solution mixed with sodium pyrophosphate, caustic soda, sodium silicate, and sodium alkyl sulfonate, heat to 80-90°C, wash for 5 minutes, remove the steel wire and rinse with tap water;

[0033] E2 Rust removal and phosphating: Immerse the degreased steel wire in a mixture of phosphoric acid, zinc oxide, sodium nitrite, and sodium hydroxide, heat it to 60-75°C, and take it out after 8 minutes;

[0034] E3 passivation: spray triacetamide on the surface of the phosphating steel wire to seal the easily oxidized ions on the surface of the steel wire.

[0035] In summary, the present invention has the following advantages compared with the prior art:

[0036] 1. In the scheme of the present invention, an adhesive film capable of bonding polyethylene pipes and metal surfaces with better bonding effect is prepared and sandwiched between the inner and outer surfaces of the steel mesh, thereby bonding the cross-linked steel mesh and the polyethylene pipe, replacing the traditional adhesive resin and avoiding the drawbacks of cumbersome application of adhesive resin and poor bonding effect. By coating relatively small-sized magnesium hydroxide particles with polyethylene-vinyl acetate copolymer to form a masterbatch, the reaction contact area is reduced during the reaction process, thereby avoiding the consumption of polar monomers during the reaction process, which leads to a decrease in the grafting rate;

[0037] 2. In the scheme of the present invention, carbon-carbon double bonds are introduced into the SMA resin by reacting SMA with an unsaturated compound, and then the SMA resin is grafted onto the polyethylene-ester copolymer molecular chain using the unsaturated bond to introduce polar maleic anhydride groups. This can increase the grafting rate and oxidation induction period of the polar groups, reduce natural volatilization, and extend the service life of the product.

[0038] 3. In the present invention, the compatibility of the adhesive film with the polyethylene resin pipeline is enhanced by adding phytic acid-modified polyvinyl alcohol. At the same time, the presence of phosphate groups greatly enhances the bonding strength between the adhesive film and the steel mesh. The polyurethane resin with multiple hydroxyl groups as the base material of the adhesive film can provide a large number of bonding points, further improving the bonding strength between the adhesive film and other materials.

[0039] 4. In the scheme of the present invention, the good adhesion of polyethylene-ester copolymer to polyethylene and maleic anhydride-modified polyethylene-ester copolymer to metal are combined with the two-way adhesion effect of phytic acid-modified polyvinyl alcohol on polyethylene and metal. The polyurethane resin with multiple hydroxyl points provides a large number of surface bonding points, so that the finished adhesive film can form a strong bond between the double-layer polyethylene pipe and the steel mesh, thereby significantly improving the overall strength of the pipe.

[0040] 5. In the scheme of the present invention, by adjusting the melting step of the raw materials, the materials will not exhibit the phenomenon of disorderly fusion and ineffective grafting, ensuring the orderly arrangement of the molecules, thereby enhancing the mechanical strength and pressure resistance of the finished composite polyethylene pipe. At the same time, the raw materials of the inner and outer pipe layers are differentiated, and antioxidants and other auxiliary materials are added to the outer pipe layer to improve the weather resistance of the pipe material, while the inner pipe layer is enhanced to enhance its resistance to high pressure by adding auxiliary materials that improve the mechanical strength, so that the wire mesh composite polyethylene pipe can withstand greater pressure from the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The peel strength test results of the embodiment of the present invention are as follows;

[0042] Figure 2 The hydrostatic strength test results of the embodiment of the present invention are shown. DETAILED DESCRIPTION

[0043] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, further description will be given below in conjunction with specific embodiments.

[0044] Example 1

[0045] Preparation of double-layer adhesive film:

[0046] 100 parts of SMA resin were fed into a melting device for melting. After the SMA resin was completely melted, 20 parts of propylene alcohol were added dropwise. The temperature was set at 180°C. After the addition was completed, the mixture was kept warm for 2 hours and cooled to obtain an unsaturated SMA resin.

[0047] The magnesium hydroxide passed through an 800-mesh sieve was dried to a moisture content of less than 0.2%. 100 parts of polyethylene-vinyl acetate copolymer and dried magnesium hydroxide were fed into a mixing device at a ratio of 1:1. The mixture was mixed at a speed of 1000 r / min for 5 minutes and then fed into a melting device for melting. The temperature was set to 160°C. After the mixture became a melt, 100 parts of unsaturated SMA resin were added. Dibenzoyl peroxide was added in batches in a quantitative manner with a single interval of 2 minutes. The amount added in a single batch was 1 / 5 of the total amount. The temperature was set to 190°C and the screw speed was 300 rpm. The mixture was extruded and granulated to obtain unsaturated SMA resin-modified polypropylene.

[0048] 100 parts of diethylene oxide and 15 parts of lithium chloride were added to a reaction vessel filled with methanol, the temperature was set at 160°C and the pressure was 1 MPa, carbon dioxide was introduced, and the reaction was stirred for 6 hours. After taking out the intermediate product, it was added to a container filled with tetrahydrofuran, and then 40 parts of diethylenetriamine were added. The temperature was raised to 190°C, the screw speed was 300 rpm, and the reaction was continued for 3 hours. After cooling, a polyurethane resin containing multiple hydroxyl sites on the surface was obtained.

[0049] 100 parts of polyvinyl alcohol resin, 5 parts of phytic acid and 2 parts of sulfuric acid were added to the solvent, and the reactor temperature was set to 55°C for 2 hours. After the reaction was completed, an alkaline solution was added to quench the reaction, and the solution was evaporated under reduced pressure. The substrate was washed with clean water and centrifuged. The precipitate was sent to an oven for drying to obtain phytic acid-modified polyvinyl alcohol resin.

[0050] 100 parts of SMA resin modified polyethylene-ester copolymer, 35 parts of polyurethane resin containing multiple hydroxyl points on the surface, and 6 parts of dibenzoyl peroxide are mixed and sent into a melting equipment for melting at a melting temperature of 185°C. After the SMA resin modified polyethylene-ester copolymer becomes a melt state, 20 parts of phytic acid modified polyvinyl alcohol resin and 10 parts of trimethylolpropane trimethacrylate are added, mixed with a high-speed mixer, and kept warm for reaction for 12 hours to allow the initiator and cross-linking agent to be fully absorbed by the polymer matrix. The adhesive particles are extruded and granulated at 80°C using an extruder, and the adhesive particles are cast at 85°C using a casting machine to obtain an adhesive film.

[0051] Example 2

[0052] Wire surface treatment:

[0053] Immerse the steel wire in an alkaline solution mixed with sodium pyrophosphate, caustic soda, sodium silicate and sodium alkyl sulfonate, heat it to 80-90℃, wash it for 5 minutes, take out the steel wire and rinse it with tap water, immerse the degreased steel wire in a mixture of phosphoric acid, zinc oxide, sodium nitrite and sodium hydroxide, heat it to 60-75℃, take it out after 8 minutes, spray triacetamide on the surface of the phosphating steel wire to seal the easily oxidized ions on the surface of the steel wire, and send it to the oven for drying before use.

[0054] Example 3

[0055] Preparation of steel wire mesh composite polyethylene pipe:

[0056] 100 parts of high-density polyethylene are weighed, 25 parts of acrylonitrile-butadiene-styrene copolymer are added, and the mixture is sent to a melting device for melting. The temperature is set to 195° C. After the high-density polyethylene becomes a melt state, 15 parts of thermoplastic elastomer SBS are added and continued to melt. Finally, 4 parts of polyethylene wax are added to the melt, and the mixture is extruded through a screw extruder, extruded through a core tube extruder, and formed through a special mold for the core tube, and then sized by a sizing sleeve. Before the core tube enters the sizing sleeve position, the temperature is pre-cooled by spraying, and the sizing sleeve is cooled to 30° C. to obtain a polyethylene inner tube layer.

[0057] The polyethylene inner tube layer coming out of the sizing sleeve is pulled by a traction machine into the first steel wire winding machine for plastic-coated steel wire winding. During the traction process, a layer of adhesive film is affixed to the outer surface of the polyethylene inner tube layer, and then it enters the second steel wire winding machine for bare steel wire winding to form a steel wire mesh structure. A second layer of adhesive film is affixed to the outside of the steel wire mesh, and finally it enters the heating device and is heated to 130°C to semi-melt the double-layer adhesive film. Pressure is applied to make the adhesive film fit the steel wire mesh and the polyethylene inner tube layer.

[0058] The pipe material obtained in the above step is fed into an outer polyethylene pipe mold, 100 parts of high-density polyethylene is taken and fed into a melting device for melting, and after the high-density polyethylene becomes a melt state, 20 parts of benzoyl peroxide, 10 parts of glucosinolates, and 8 parts of tris(nonylphenol) phosphite are added and stirred to melt at 190° C. After becoming a melt, the temperature is lowered to 170° C., 5 parts of carboxymethyl cellulose and 4 parts of polyethylene wax are added, and the mixture is extruded into the outer polyethylene pipe mold through a twin-screw extruder. The melt semi-melts the outer layer adhesive film to form a polyethylene outer pipe layer. The composite pipe is cooled in a vacuum water tank, towed by a rear traction machine, and cut according to the specified size to obtain a steel mesh composite polyethylene pipe.

[0059] Example 4

[0060] This example is a comparative example of Example 1. Adhesive films were prepared after adjusting certain conditions, and performance tests were conducted on polyethylene composite pipes made using certain adhesive films.

[0061] a. The weight percentages of the raw materials for the double-layer adhesive film were adjusted. Specifically, the weight percentages of the raw materials were: 100 parts of SMA resin-modified polyethylene - ester copolymer, 20 parts of a polyurethane resin having a plurality of hydroxyl sites on the surface, 15 parts of a phytic acid-modified polyvinyl alcohol resin, 3 parts of an initiator, and 5 parts of a cross-linking agent. Other conditions remained unchanged, and the prepared adhesive film was referred to as adhesive film A.

[0062] b. The mass fractions of the raw materials of the unsaturated SMA resin-modified polypropylene were adjusted. The specific mass fractions of the raw materials were as follows: the mass ratio of the polyethylene-ester copolymer to the unsaturated SMA resin was 1:0.5, and the mass ratio of the polyethylene-ester copolymer to the magnesium hydroxide powder was 1:0.8. Other conditions remained unchanged. The prepared adhesive film was recorded as Adhesive Film B.

[0063] c. The mass fraction of the raw materials of the SMA resin was adjusted. Specifically, the mass fraction of the raw materials was as follows: the mass ratio of the SMA resin to the unsaturated compound was 1:0.1. Other conditions remained unchanged. The prepared adhesive film was recorded as adhesive film C.

[0064] d. The mass fraction of the raw material of the polyurethane resin containing multiple hydroxyl sites on the surface was adjusted. The specific mass fraction of the raw material was: the mass ratio of dioxirane to catalyst was 1:0.05. Other conditions remained unchanged. The prepared adhesive film was recorded as adhesive film D.

[0065] The adhesive films A, B, C and D were used to prepare steel mesh composite polyethylene tubes, respectively, to obtain polyethylene tube A, polyethylene tube B, polyethylene tube C and polyethylene tube D;

[0066] Referring to GB / T 2791-1995 "Adhesive T-peel Strength Test Method - Flexible Material to Flexible Material," the peel strengths of the steel wire mesh composite polyethylene tube obtained in Example 3 and polyethylene tubes A, B, C, and D were measured. In addition, commercially available products were also tested for comparison. The test results are shown in Table 1.

[0067] .

[0068] Example 5

[0069] This example is a comparative example of Example 1. After adjusting several conditions, steel wire mesh composite polyethylene pipes were prepared, and the performance of several steel wire mesh composite polyethylene pipes prepared was tested.

[0070] a polyethylene inner tube layer of raw materials parts by mass are adjusted, specific parts by mass of raw materials are: 100 parts high-density polyethylene, 18 parts acrylonitrile - butadiene - styrene copolymer, 10 parts toughening agent, 4 parts polyethylene wax, other conditions remain unchanged, the preparation of steel mesh composite polyethylene pipe recorded as polyethylene pipe I;

[0071] b. The weight percentages of the raw materials for the polyethylene outer tube layer were adjusted. The specific weight percentages of the raw materials were: 100 parts high-density polyethylene, 15 parts benzoyl peroxide, 7 parts corrosion inhibitor, 5 parts antioxidant, 3 parts carboxymethyl cellulose, and 4 parts polyethylene wax. Other conditions remained unchanged. The prepared steel mesh composite polyethylene tube was designated as polyethylene tube II.

[0072] c. The raw material components of the polyethylene outer tube layer were adjusted, bisphenol A epoxy resin was selected as the anti-corrosion agent, triphenyl phosphite was selected as the antioxidant, and high-density polyethylene fiber was selected as the toughening agent. The mass fractions of the raw materials were the same as in Example 3, and other conditions remained unchanged. The prepared steel mesh composite polyethylene tube was designated as polyethylene tube III.

[0073] d. The raw material components of the polyethylene outer tube layer were adjusted, the corrosion inhibitor was EVA resin, the antioxidant was 2,6-di-tert-butyl-4-methylphenol, and the toughening agent was nano-boron fiber. The mass fractions of the raw materials were the same as in Example 3. Other conditions remained unchanged. The prepared steel mesh composite polyethylene tube was designated as polyethylene tube IV.

[0074] With reference to GB / T 32439-2015 "Steel Wire Mesh Reinforced Polyethylene Composite Pipes for Water Supply," the performance of the steel wire mesh composite polyethylene pipe obtained in Example 3 was measured along with polyethylene pipes I, II, III, and IV. In addition, commercially available products were also tested for comparison. The test results are shown in Table 2.

[0075] .

[0076] The embodiments of the present invention are not limited to the above embodiments. Without departing from the spirit and scope of the present invention, ordinary technicians in this field can make various changes and improvements to the present invention in form and details, and these are all considered to fall within the scope of protection of the present invention.

Claims

1. A method for preparing a steel wire mesh composite polyethylene pipe, characterized in that: The steel wire mesh composite polyethylene pipe is composed of a polyethylene outer tube layer, a polyethylene inner tube layer, a steel wire mesh and a double-layer adhesive film, wherein the double-layer adhesive film sandwiches the steel wire mesh, and the raw material components of the polyethylene outer tube layer include high-density polyethylene, benzoyl peroxide, an anti-corrosion agent, an antioxidant, carboxymethyl cellulose, and polyethylene wax; the raw material components of the polyethylene inner tube layer include high-density polyethylene, acrylonitrile-butadiene-styrene copolymer, a toughening agent, and polyethylene wax; the raw material components of the double-layer adhesive film include a polyurethane resin containing multiple hydroxyl points on the surface, an SMA resin-modified polyethylene-ester copolymer, a phytic acid-modified polyvinyl alcohol resin, an initiator, and a cross-linking agent; The anti-corrosion agent is selected from one or more of glucosinolate, bisphenol A epoxy resin and EVA resin; The antioxidant is selected from one or more of tris(nonylphenol) phosphite, triphenyl phosphite and 2,6-di-tert-butyl-4-methylphenol; The toughening agent is selected from one or more of thermoplastic elastomer SBS, high-density polyethylene fiber and nano boron fiber; The initiator is selected from one or more of dibenzoyl peroxide, tert-butyl peroxide 3,5,5-trimethylhexanoate, tert-amyl peroxybenzoate, and tert-butyl peroxide 2-ethylhexyl carbonate; The cross-linking agent is selected from one or more of trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, and pentaerythritol triacrylate; The preparation method of the steel wire mesh composite polyethylene pipe comprises the following steps: S1: High-density polyethylene and acrylonitrile-butadiene-styrene copolymer are uniformly mixed and then fed into a melting device for melting. A toughening agent is added after the high-density polyethylene becomes a melt state. After all the high-density polyethylene is melted, polyethylene wax is added. The polyethylene is extruded through a twin-screw extruder, and after being shaped by a mold, a core tube is formed and then sized. Before the core tube enters the sizing sleeve, it is cooled in advance by spraying, and the sizing sleeve is cooled. After sizing, the polyethylene inner tube layer is obtained; S2: The polyethylene inner tube layer is fed into the steel wire winding equipment through a traction machine. A layer of adhesive film is first covered on the outer surface of the polyethylene inner tube layer. Steel wires are woven into a mesh on the surface of the polyethylene inner tube layer to form a steel mesh. Then, another layer of adhesive film is covered. The adhesive film is heated until it is semi-molten and pressure is applied to adhere the double-layer adhesive film to the polyethylene inner tube layer and the steel mesh. S3: High-density polyethylene is sent to a melting device for melting. After the high-density polyethylene becomes a melt state, evenly mixed benzoyl peroxide, anti-corrosion agent, and antioxidant are added, and the mixture is stirred while being kept warm. After cooling down by 20°C, carboxymethyl cellulose and polyethylene wax are added, and the mixture is sent to a twin-screw extruder for extrusion and coating on the outer surface of a double-layer adhesive film to form a polyethylene outer tube layer. After cooling, a steel wire mesh skeleton composite tube is obtained.

2. The method for preparing a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that: The preparation method of the double-layer adhesive film is as follows: T1: SMA resin modified polyethylene-ester copolymer, polyurethane resin containing multiple hydroxyl points on the surface, and initiator are first mixed and sent to a melting device for melting. After the SMA resin modified polyethylene-ester copolymer becomes a melt, phytic acid modified polyvinyl alcohol resin and a cross-linking agent are added. After all are melted, they are sent to an extruder for extrusion and granulation to obtain adhesive particles; T2: Feed the adhesive particles into the casting equipment and set the casting temperature to 85~110℃. After the casting is completed, a film sheet, i.e., an adhesive film, is obtained.

3. The method for preparing a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that: The preparation method of the SMA resin-modified polyethylene-ester copolymer comprises: mixing the polyethylene-ester copolymer with dry magnesium hydroxide powder and performing a melt reaction; adding an unsaturated SMA resin and an initiator after the melting is completed to perform a melt grafting reaction; grafting the SMA resin onto the polyethylene-ester copolymer molecular chain through the unsaturated bonds in the unsaturated SMA resin; and extruding and granulating to obtain the unsaturated SMA resin-modified polypropylene; The polyethylene-ester copolymer is selected from one or more of polyethylene-vinyl acetate copolymer, polyethylene-methyl acrylate copolymer, polyethylene-ethyl acrylate copolymer and polyethylene-butyl acrylate copolymer; The mass ratio of polyethylene-ester copolymer to unsaturated SMA resin is 1:0.5~1; the mass ratio of polyethylene-ester copolymer to magnesium hydroxide powder is 1:0.8~1; the temperature of the melt reaction is 140~180℃, and the temperature of the melt grafting reaction is 160~210℃; the initiator is added to the melting equipment in batches, with a single interval of 2 minutes, and the amount added in a single batch is 1 / 5 of the total amount of initiator.

4. The method for preparing a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that: The preparation method of the SMA resin comprises: completely melting the SMA resin and then dropwise adding an unsaturated compound containing a double bond, and obtaining the unsaturated SMA resin after the reaction is completed; The unsaturated compound is selected from one or more of propylene glycol, methyl propylene glycol, maleic acid hydrazide, and acrylamide; the mass ratio of SMA resin to unsaturated compound is 1:0.1-0.2; the reaction temperature is 150-190°C, and the reaction time is 1.5-2h.

5. The method for preparing a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that: The preparation method of the polyurethane resin containing multiple hydroxyl sites on the surface comprises: reacting dioxirane with carbon dioxide in the presence of a catalyst to generate an intermediate product, and then reacting the intermediate product with diethylenetriamine to generate the polyurethane resin containing multiple hydroxyl sites on the surface; The catalyst is selected from one or more of lithium chloride, sodium bromide, and sodium iodide; the feed mass ratio of dioxirane to catalyst is 1:0.05-0.15; the reaction temperature is 90-160°C; and the reaction solvent is selected from one or more of N,N-dimethylformamide, methanol, and tetrahydrofuran.

6. The method for preparing a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that: The preparation method of the phytic acid modified polyvinyl alcohol resin comprises the following steps: dissolving polyvinyl alcohol in a solution, adding phytic acid and sulfuric acid as catalysts to carry out an esterification reaction, and washing the product with water and centrifugally drying the product to obtain the phytic acid modified polyvinyl alcohol resin.

7. The method for preparing a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that: The raw materials of the polyethylene outer tube layer are 100 parts by weight of high-density polyethylene, 15-20 parts by weight of benzoyl peroxide, 7-10 parts by weight of anti-corrosion agent, 5-8 parts by weight of antioxidant, 3-5 parts by weight of carboxymethyl cellulose and 4 parts by weight of polyethylene wax.

8. The method for preparing a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that: The raw materials of the polyethylene inner tube layer are 100 parts by weight of high-density polyethylene, 18-25 parts by weight of acrylonitrile-butadiene-styrene copolymer, 10-15 parts by weight of toughening agent, and 4 parts by weight of polyethylene wax.

9. The method for preparing a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that: The raw materials of the double-layer adhesive film are 100 parts by weight of SMA resin-modified polyethylene-ester copolymer, 20-35 parts of polyurethane resin containing multiple hydroxyl points on the surface, 15-20 parts of phytic acid-modified polyvinyl alcohol resin, 3-6 parts of initiator, and 5-10 parts of crosslinking agent.

10. The method for preparing a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that: In step S2, the steel wires undergo a surface treatment process before being woven into a steel wire mesh. The surface treatment process includes the following steps: E1 Degreasing: Immerse the steel wire in an alkaline solution mixed with sodium pyrophosphate, caustic soda, sodium silicate, and sodium alkyl sulfonate, heat to 80-90°C, wash for 5 minutes, remove the steel wire and rinse with tap water; E2 Rust removal and phosphating: Immerse the degreased steel wire in a mixture of phosphoric acid, zinc oxide, sodium nitrite, and sodium hydroxide, heat it to 60-75°C, and take it out after 8 minutes; E3 passivation: spray triacetamide on the surface of the phosphating steel wire to seal the easily oxidized ions on the surface of the steel wire.

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