Preparation method of steel wire mesh composite polyethylene pipe

Abstract

The invention provides a preparation method of a steel wire mesh composite polyethylene pipe, and relates to the field of polyethylene pipe manufacturing, the steel wire mesh composite polyethylene pipe is composed of a polyethylene outer pipe layer, a polyethylene inner pipe layer, a steel wire mesh and a double-layer adhesive film, the polyethylene outer pipe layer comprises the following raw material components: high-density polyethylene, benzoyl peroxide, a corrosion inhibitor, an antioxidant, carboxymethyl cellulose and polyethylene wax, and the polyethylene inner pipe layer comprises the following raw material components: high-density polyethylene, an acrylonitrile-butadiene-styrene copolymer, a flexibilizer and polyethylene wax. The double-layer adhesive film comprises the following raw material components: polyurethane resin with a plurality of hydroxyl sites on the surface, SMA resin modified polyethylene-ester copolymer, phytic acid modified polyvinyl alcohol resin, an initiator and a cross-linking agent; the polyethylene pipe material has the advantages of being good in pressure resistance, good in bonding effect between the polyethylene pipe material and the steel wire mesh, and good in mechanical performance on the whole.

Description

Technical Field

[0001] The present invention relates to the field of polyethylene pipe manufacturing, and particularly to a preparation method of a steel wire mesh composite polyethylene pipe. Background Art

[0002] The steel wire mesh composite polyethylene pipe, namely the steel wire mesh skeleton polyethylene composite pipe, is a new type of composite pipe. With high-strength steel wire winding as the reinforcement skeleton, the outer layer and the inner layer are made of polyethylene materials, and multiple layers of steel wire mesh-shaped reinforcement layers are arranged in the middle. The outer layer of the steel wire is coated with a coating layer with hot melt bonding and water blocking functions. This kind of pipe combines the strength of the steel wire mesh and the corrosion resistance and flexibility of polyethylene, and has excellent performance. Due to its unique pressure resistance strength, it can be used for special purposes such as fire fighting water supply, and the requirements of fire fighting water supply pipes also pose a great test to the performance of the steel wire mesh composite polyethylene pipe.

[0003] Since the requirement for the pressure resistance performance of the fire fighting water supply pipe is to be able to maintain a pressure of 1.20 MPa for a long time, and under special requirements, it should also be able to maintain a working pressure of 1.60 MPa in a short time, which is also a relatively high standard for the steel wire mesh composite polyethylene pipe. The raw materials of the inner and outer pipe layers of the common steel wire mesh composite polyethylene pipe are the same. Although the consistency of the pipe is guaranteed, it also causes the disadvantage that the inner pipe layer cannot resist higher strength pressure. After the working pressure instantaneously increases, if cracks appear in the inner pipe layer, this consistency will also cause the pipe to be quickly damaged.

[0004] In addition, common steel wire mesh composite polyethylene pipes usually use an adhesive resin arranged on the outer side of the steel wire mesh layer to improve the crosslinking effect between the steel wire mesh and the inner and outer polyethylene pipe layers, thereby improving the overall performance of the steel wire mesh composite polyethylene pipe. However, the properties of the adhesive resin and polyethylene are ultimately different. The greater the thickness of the adhesive resin, the more negative impact it will have on the structural stability of the steel wire mesh composite polyethylene pipe. And the conventional adhesive resin with a low thickness cannot achieve a good bonding effect between the steel wire mesh and the inner and outer polyethylene pipe layers. At the same time, the process of coating the adhesive resin is generally after winding the steel wire mesh. At this time, the operating space around the pipe material is relatively narrow, the coating process is extremely cumbersome, and the operation difficulty is large.

[0005] The publicly disclosed patent CN115195168A discloses a steel wire mesh skeleton composite pipe and its production method. This solution is to set a hot melt adhesive layer between the inner polyethylene layer and the outer polyethylene layer, and the raw material components of the inner polyethylene pipe layer and the outer polyethylene pipe layer are the same. If it is applied to the fire fighting water supply pipe, it cannot maintain a working pressure of up to 1.60 MPa for a long time. After the inner polyethylene layer is damaged, the hot melt adhesive layer and the steel wire mesh layer will be peeled off by the water pressure in a short time, and the whole pipe will disintegrate extremely quickly. Summary of the Invention

[0006] In view of the defects existing in the above prior art, the present invention provides a preparation method of a steel wire mesh composite polyethylene pipe, and the problems to be solved are to enhance the pressure resistance of the steel wire mesh composite polyethylene pipe and the bonding effect between the steel wire mesh and the polyethylene pipe material.

[0007] The object of the present invention is achieved through the following technical solutions. The steel wire mesh composite polyethylene pipe is composed of a polyethylene outer pipe layer, a polyethylene inner pipe layer, a steel wire mesh and a double-layer bonding film. The double-layer bonding film sandwiches the steel wire mesh. The raw material components of the polyethylene outer pipe layer include high-density polyethylene, benzoyl peroxide, corrosion inhibitor, antioxidant, carboxymethyl cellulose, and polyethylene wax. The raw material components of the polyethylene inner pipe layer include high-density polyethylene, acrylonitrile-butadiene-styrene copolymer, toughening agent, and polyethylene wax. The raw material components of the double-layer bonding film include a polyurethane resin with a plurality of hydroxyl sites on the surface, an SMA resin-modified polyethylene-ester copolymer, a phytic acid-modified polyvinyl alcohol resin, an initiator, and a crosslinking agent; The corrosion inhibitor 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 benzoyl peroxide, tert-butyl 3,5,5-trimethylhexanoate peroxide, tert-amyl benzoate peroxide, and tert-butyl 2-ethylhexyl carbonate peroxide; The crosslinking 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 includes the following steps: S1: Mix high-density polyethylene and acrylonitrile-butadiene-styrene copolymer evenly and send them into a melting device for melting. After the high-density polyethylene becomes a molten state, add a toughening agent, and after all melting is completed, add polyethylene wax. Extrude through a twin-screw extruder, form a core pipe after sizing through a mold, and cool in advance by spraying before the core pipe enters the sizing sleeve position, and cool the sizing sleeve. After sizing, the polyethylene inner pipe layer is obtained; S2: Send the polyethylene inner pipe layer into a steel wire winding device through a tractor. First, cover a layer of bonding film on the outer surface of the polyethylene inner pipe layer. After weaving the steel wire into a mesh on the surface of the polyethylene inner pipe layer to form a steel wire mesh, cover another layer of bonding film, heat to the semi-molten state of the bonding film and apply pressure to make the double-layer bonding film fit with the polyethylene inner pipe layer and the steel wire mesh; S3: Feed high-density polyethylene into a smelting device for melting. After the high-density polyethylene becomes a molten state, add uniformly mixed benzoyl peroxide, corrosion inhibitor, and antioxidant, keep warm and stir. After cooling by 20 °C, add carboxymethyl cellulose and polyethylene wax, and feed them into a twin-screw extruder for extrusion and coating on the outer surface of the double-layer adhesive film to form a polyethylene outer pipe layer. After cooling is completed, a steel wire mesh skeleton composite pipe is obtained.

[0008] In the above preparation method of a steel wire mesh composite polyethylene pipe, preferably, the preparation method of the double-layer adhesive film is as follows: T1: First, mix SMA resin-modified polyethylene-ester copolymer, polyurethane resin with a plurality of hydroxyl sites on the surface, and an initiator and feed them into a smelting device for melting. After the SMA resin-modified polyethylene-ester copolymer becomes a molten state, add phytic acid-modified polyvinyl alcohol resin and a cross-linking agent. After all melting is completed, feed them into an extruder for extrusion and granulation to obtain adhesive particles; T2: Feed the adhesive particles into a casting device, set the casting temperature to 85 - 110 °C, and after casting is completed, obtain a film, which is the adhesive film.

[0009] In the above preparation method of a steel wire mesh composite polyethylene pipe, preferably, the preparation method of the SMA resin-modified polyethylene-ester copolymer is as follows: Mix polyethylene-ester copolymer and dry magnesium hydroxide powder and carry out a melting reaction. After the melting is completed, add unsaturated SMA resin and an initiator for a melt grafting reaction. Graft the SMA resin onto the molecular chain of the polyethylene-ester copolymer through the unsaturated bonds in the unsaturated SMA resin, and extrude and granulate to obtain unsaturated SMA resin-modified polypropylene; 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; Furthermore, the feeding mass ratio of the polyethylene-ester copolymer to the unsaturated SMA resin is 1:0.5 - 1; the feeding mass ratio of the polyethylene-ester copolymer to the magnesium hydroxide powder is 1:0.8 - 1; the temperature of the melting reaction is 140 - 180 °C, and the temperature of the melt grafting reaction is 160 - 210 °C; the initiator is added to the smelting device in batches, with an interval of 2 min each time, and the single batch addition amount is 1 / 5 of the total amount of the initiator.

[0010] In the above preparation method of a steel wire mesh composite polyethylene pipe, preferably, the preparation method of the SMA resin is as follows: After the SMA resin is completely melted, drop an unsaturated compound containing a double bond, and after the reaction is completed, obtain unsaturated SMA resin; Further, the unsaturated compound is selected from one or more of allyl alcohol, methallyl alcohol, maleic hydrazide, and acryldiamine; the feeding mass ratio of the SMA resin to the unsaturated compound is 1:0.1 - 0.2; the reaction temperature is 150 - 190 °C, and the reaction time is 1.5 - 2 h.

[0011] In the above preparation method of a steel wire mesh composite polyethylene pipe, preferably, the preparation method of the polyurethane resin with a plurality of hydroxyl sites on the surface is as follows: bis(ethylene oxide) reacts with carbon dioxide in the presence of a catalyst to form an intermediate product, and the intermediate product then reacts with diethylenetriamine to form a polyurethane resin with a plurality of hydroxyl sites on the surface; Further, the catalyst is selected from one or more of lithium chloride, sodium bromide, and sodium iodide, the feeding mass ratio of bis(ethylene oxide) to the 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.

[0012] In the above preparation method of a steel wire mesh composite polyethylene pipe, preferably, the preparation method of the phytic acid-modified polyvinyl alcohol resin is as follows: polyvinyl alcohol is dissolved in a solution, phytic acid is added, and sulfuric acid is added as a catalyst for an esterification reaction. The product is washed with water, centrifuged, and dried to obtain the phytic acid-modified polyvinyl alcohol resin.

[0013] In the above preparation method of a steel wire mesh composite polyethylene pipe, preferably, the raw material mass parts of the polyethylene outer tube layer are 100 parts of high-density polyethylene, 15 - 20 parts of benzoyl peroxide, 7 - 10 parts of corrosion inhibitor, 5 - 8 parts of antioxidant, 3 - 5 parts of carboxymethyl cellulose, and 4 parts of polyethylene wax.

[0014] In the above preparation method of a steel wire mesh composite polyethylene pipe, preferably, the raw material mass parts of the polyethylene inner tube layer are 100 parts of high-density polyethylene, 18 - 25 parts of acrylonitrile-butadiene-styrene copolymer, 10 - 15 parts of toughening agent, and 4 parts of polyethylene wax.

[0015] In the above preparation method of a steel wire mesh composite polyethylene pipe, preferably, the raw material mass parts of the double-layer adhesive film are 100 parts of SMA resin-modified polyethylene-ester copolymer, 20 - 35 parts of polyurethane resin with a plurality of hydroxyl sites 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.

[0016] In the above preparation method of a steel wire mesh composite polyethylene pipe, preferably, in step S2, the steel wire also undergoes a surface treatment process before being woven into a steel wire mesh. The surface treatment includes the following steps: E1 Degreasing: Immerse the steel wire in an alkaline solution composed of sodium pyrophosphate, caustic soda, sodium silicate, and sodium alkyl sulfonate. Heat it up to 80 - 90 °C, clean for 5 minutes, take out the steel wire and rinse it with tap water; E2 Rust Removal and Phosphating: Immerse the degreased steel wire in a mixed solution of phosphoric acid, zinc oxide, sodium nitrite, and sodium hydroxide. Heat it up to 60 - 75 °C and take it out after 8 minutes; E3 Passivation: Spray triethylamine on the surface of the steel wire after phosphating to seal the easily oxidized ions on the surface of the steel wire.

[0017] In summary, compared with the prior art, the present invention has the following advantages: 1. In the solution of the present invention, by preparing an adhesive film that can bond polyethylene pipe materials and metal surfaces with better bonding effect, and sandwiching it on the inner and outer surfaces of the steel wire mesh, it can play the role of bonding and crosslinking the steel wire mesh and polyethylene pipe materials, replacing the traditional adhesive resin, avoiding the drawbacks of cumbersome operation and poor bonding effect of applying adhesive resin. By coating magnesium hydroxide particles with relatively small particle size on polyethylene - vinyl acetate copolymer to form masterbatch, during the reaction process, the reaction contact area is reduced, and the consumption of polar monomers during the reaction is avoided, resulting in a decrease in grafting rate; 2. In the solution of the present invention, by reacting SMA with unsaturated compounds to introduce carbon - carbon double bonds into the SMA resin, and then grafting the SMA resin onto the molecular chain of polyethylene - ester copolymer using unsaturated bonds, polar maleic anhydride groups can be introduced, which can improve the grafting rate of polar groups and oxidation induction period, and can reduce natural volatilization and increase the service life of the product; 3. In the solution of the present invention, by adding phytic acid - modified polyvinyl alcohol, the compatibility between the adhesive film and the polyethylene resin pipeline is enhanced. At the same time, due to the presence of phosphate groups, the bonding strength between the adhesive film and the steel wire mesh is greatly enhanced. The polyurethane resin with multiple hydroxyl sites as the base material of the adhesive film can provide a large number of binding sites, further improving the bonding strength between the adhesive film and other materials; 4. In the solution of the present invention, combining the good adhesiveness of polyethylene - ester copolymer to polyethylene, the good adhesiveness of maleic anhydride - modified polyethylene - ester copolymer to metal, and supplemented by the two - way adhesive effect of phytic acid - modified polyvinyl alcohol on polyethylene and metal, and the large number of surface binding sites provided by the polyurethane resin with multiple hydroxyl sites, the finished adhesive film can form a firm bond with the steel wire mesh between the double - layer polyethylene pipe materials, which has a good improvement on the overall strength of the pipe materials; 5. In the solution of the present invention, by adjusting the melting step of the raw materials, the phenomenon of disordered fusion and ineffective grafting of the materials is avoided, the orderly arrangement of molecules is ensured, thereby enhancing the mechanical strength and pressure resistance effect of the finished composite polyethylene pipe. At the same time, the raw materials of the inner and outer pipe layers are distinguished. 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 with auxiliary materials for improving mechanical strength to enhance the resistance of the inner pipe layer to high pressure, so that the steel wire mesh composite polyethylene pipe can resist greater pressure from inside the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the test result of the peel strength of the embodiment of the present invention; Figure 2 It is the test result of the hydrostatic strength of the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] In order to describe in detail the technical content, structural features, achieved purposes and effects of the present invention, the following further description is made in conjunction with specific embodiments.

[0020] Example 1 Preparation of double-layer adhesive film: Feed 100 parts of SMA resin into the melting equipment for melting. After the SMA resin is completely melted, drop 20 parts of allyl alcohol, set the temperature at 180 °C, keep the temperature for 2 h after dropping, and obtain unsaturated SMA resin after cooling.

[0021] Dry magnesium hydroxide passing through an 800-mesh sieve until the moisture content is lower than 0.2%. Feed 100 parts of polyethylene-vinyl acetate copolymer and the dried magnesium hydroxide into the mixing equipment at a ratio of 1:1, set the parameter at 1000 r / min and mix for 5 min, then feed it into the melting equipment for melting, set the temperature at 160 °C. After it becomes a melt, add 100 parts of unsaturated SMA resin, add dibenzoyl peroxide in batches quantitatively, with an interval of 2 min each time, and the single-batch addition amount is 1 / 5 of the total amount. Set the temperature at 190 °C and the screw speed at 300 rpm, and extrude and pelletize to obtain unsaturated SMA resin-modified polypropylene.

[0022] Feed 100 parts of diepoxyethane and 15 parts of lithium chloride into the reaction vessel filled with methanol, set the conditions of temperature at 160 °C and pressure at 1 MPa, introduce carbon dioxide, stir and react for 6 h. After taking out the intermediate product, add it into the container filled with tetrahydrofuran, then add 40 parts of diethylenetriamine, raise the temperature to 190 °C, and the screw speed is 300 rpm, and continue to react for 3 h. After cooling, obtain polyurethane resin with a plurality of hydroxyl sites on the surface.

[0023] Add 100 parts of polyvinyl alcohol resin, 5 parts of phytic acid, and 2 parts of sulfuric acid to the solvent. Set the temperature of the reaction kettle to 55 °C and react for 2 h. After the reaction is completed, add an alkaline solution to quench the reaction. Evaporate the solution under reduced pressure. Wash the substrate with water, centrifuge, and send the precipitate to an oven for drying to obtain phytic acid-modified polyvinyl alcohol resin.

[0024] Mix 100 parts of SMA resin-modified polyethylene-ester copolymer, 35 parts of polyurethane resin with multiple hydroxyl sites on the surface, and 6 parts of dibenzoyl peroxide and send them into a melting equipment for melting. The melting temperature is 185 °C. After the SMA resin-modified polyethylene-ester copolymer becomes a molten state, add 20 parts of phytic acid-modified polyvinyl alcohol resin and 10 parts of trimethylolpropane trimethacrylate, and mix them with a high-speed mixer. Keep the temperature for reaction for 12 h to fully absorb the initiator and crosslinking agent by the polymer matrix. Extrude and pelletize at 80 °C with an extruder to obtain adhesive particles. Cast the adhesive particles with a casting machine at 85 °C to obtain an adhesive film.

[0025] Example 2 Steel wire surface treatment: Immerse the steel wire in an alkaline solution mixed with sodium pyrophosphate, caustic soda, sodium silicate, and sodium alkyl sulfonate, heat up to 80 - 90 °C, wash for 5 min, take out the steel wire and rinse it with tap water. Immerse the degreased steel wire in a mixed solution of phosphoric acid, zinc oxide, sodium nitrite, and sodium hydroxide, heat up to 60 - 75 °C, take it out after 8 min. Spray triethylamine on the surface of the phosphated steel wire to seal the easily oxidized ions on the steel wire surface, and send it to an oven for drying for standby.

[0026] Example 3 Preparation of steel wire mesh composite polyethylene pipe: Weigh 100 parts of high-density polyethylene, add 25 parts of acrylonitrile-butadiene-styrene copolymer and mix them, then send them into a melting equipment for melting. Set the temperature to 195 °C. After the high-density polyethylene becomes a molten state, add 15 parts of thermoplastic elastomer SBS and continue melting. Finally, add 4 parts of polyethylene wax to the melt. Extrude through a screw extruder, extrude through a core pipe extruder and form through a special core pipe mold, then carry out sizing with a sizing sleeve. Cool in advance by spraying before the core pipe enters the sizing sleeve position, cool the sizing sleeve, and cool down to 30 °C to obtain a polyethylene inner pipe layer.

[0027] The polyethylene inner tube layer coming out of the sizing sleeve is pulled by a tractor and enters the first wire winding machine for plastic-coated wire winding. During the pulling process, an adhesive film is pasted on the outer surface of the polyethylene inner tube layer, and then it enters the second wire winding machine for bare wire winding to form a wire mesh structure. Then, a second adhesive film is pasted on the outside of the wire mesh. Finally, it enters a heating device and is heated to 130 °C to semi-melt the double-layer adhesive film, and pressure is applied to make the adhesive film fit with the wire mesh and the polyethylene inner tube layer.

[0028] The pipe material obtained in the above step is fed into the outer polyethylene pipe mold. 100 parts of high-density polyethylene are fed into the melting equipment for melting. After the high-density polyethylene becomes a melt state, 20 parts of benzoyl peroxide, 10 parts of glucosinolate, and 8 parts of tris(nonylphenol) phosphite, which are evenly mixed, are added. It is kept warm and stirred at 190 °C for melting. After becoming a melt, the temperature is lowered to 170 °C, and 5 parts of carboxymethyl cellulose and 4 parts of polyethylene wax are added. It is extruded through a twin-screw extruder into the outer polyethylene pipe mold. The melt semi-melts the adhesive film on the outer layer to form the polyethylene outer tube layer. The composite pipe is cooled by a vacuum water tank, pulled by a rear tractor, and cut according to the specified dimensions to obtain a wire mesh composite polyethylene pipe.

[0029] Example 4 This example is a comparative example of Example 1. After adjusting several conditions, an adhesive film is prepared again, and the performance of the polyethylene composite pipes made with several adhesive films is tested; a. Adjust the raw material mass fractions of the double-layer adhesive film. The specific raw material mass fractions are: 100 parts of SMA resin-modified polyethylene-ester copolymer, 20 parts of polyurethane resin with multiple hydroxyl sites on the surface, 15 parts of phytic acid-modified polyvinyl alcohol resin, 3 parts of initiator, and 5 parts of cross-linking agent. Other conditions remain unchanged. The prepared adhesive film is denoted as adhesive film A; b. Adjust the raw material mass fractions of unsaturated SMA resin-modified polypropylene. The specific raw material mass fractions are: the feeding mass ratio of polyethylene-ester copolymer to unsaturated SMA resin is 1:0.5, and the feeding mass ratio of polyethylene-ester copolymer to magnesium hydroxide powder is 1:0.8. Other conditions remain unchanged. The prepared adhesive film is denoted as adhesive film B; c. Adjust the raw material mass fractions of SMA resin. The specific raw material mass fractions are: the feeding mass ratio of SMA resin to unsaturated compound is 1:0.1. Other conditions remain unchanged. The prepared adhesive film is denoted as adhesive film C; d. Adjust the raw material mass fractions of polyurethane resin with multiple hydroxyl sites on the surface. The specific raw material mass fractions are: the feeding mass ratio of diepoxyethane to catalyst is 1:0.05. Other conditions remain unchanged. The prepared adhesive film is denoted as adhesive film D; The above-mentioned adhesive films A, B, C, and D were respectively used in the preparation of steel wire mesh composite polyethylene pipes to obtain polyethylene pipes A, B, C, and D; Referring to GB / T 2791-1995 "Test Method for T-Peel Strength of Adhesives - Flexible Material to Flexible Material", the peel strength of the steel wire mesh composite polyethylene pipes obtained in Example 3 and polyethylene pipes A, B, C, and D was measured. In addition, commercially available products were obtained for comparative testing together, and the test results are shown in Table 1: 。

[0030] Example 5 This example is the comparative example of Example 1. After adjusting several conditions, steel wire mesh composite polyethylene pipes were prepared again, and performance tests were carried out on the obtained several steel wire mesh composite polyethylene pipes; a. Adjust the mass parts of the raw materials for the inner polyethylene pipe layer. The specific mass parts of the raw materials are: 100 parts of high-density polyethylene, 18 parts of acrylonitrile-butadiene-styrene copolymer, 10 parts of toughening agent, and 4 parts of polyethylene wax. Other conditions remain unchanged. The prepared steel wire mesh composite polyethylene pipe is denoted as polyethylene pipe I; b. Adjust the mass parts of the raw materials for the outer polyethylene pipe layer. The specific mass parts of the raw materials are: 100 parts of high-density polyethylene, 15 parts of benzoyl peroxide, 7 parts of anti-corrosion agent, 5 parts of antioxidant, 3 parts of carboxymethyl cellulose, and 4 parts of polyethylene wax. Other conditions remain unchanged. The prepared steel wire mesh composite polyethylene pipe is denoted as polyethylene pipe II; c. Adjust the raw material components of the outer polyethylene pipe layer. The anti-corrosion agent is selected as bisphenol A epoxy resin, the antioxidant is selected as triphenyl phosphite, and the toughening agent is selected as high-density polyethylene fiber. The mass parts of the raw materials are the same as in Example 3. Other conditions remain unchanged. The prepared steel wire mesh composite polyethylene pipe is denoted as polyethylene pipe III; d. Adjust the raw material components of the outer polyethylene pipe layer. The anti-corrosion agent is selected as EVA resin, the antioxidant is selected as 2,6-di-tert-butyl-4-methylphenol, and the toughening agent is selected as nano boron fiber. The mass parts of the raw materials are the same as in Example 3. Other conditions remain unchanged. The prepared steel wire mesh composite polyethylene pipe is denoted as polyethylene pipe IV; Referring to GB / T 32439-2015 "Steel Wire Mesh Reinforced Polyethylene Composite Pipes for Water Supply", the performance of the steel wire mesh composite polyethylene pipes obtained in Example 3 and polyethylene pipes I, II, III, and IV was measured. In addition, commercially available products were obtained for comparative testing together, and the test results are shown in Table 2: 。

[0031] The embodiments of the present invention are not limited to those described in the above embodiments. Without departing from the spirit and scope of the present invention, those of ordinary skill in the art can make various changes and improvements in form and detail, and these are all considered to fall within the protection scope of the present invention.

Claims

1. A preparation method of a steel wire mesh composite polyethylene pipe, characterized in that: The steel wire mesh composite polyethylene pipe is composed of a polyethylene outer pipe layer, a polyethylene inner pipe layer, a steel wire mesh and a double-layer adhesive film. The double-layer adhesive film sandwiches the steel wire mesh. The raw material components of the polyethylene outer pipe layer include high-density polyethylene, benzoyl peroxide, corrosion inhibitor, antioxidant, carboxymethyl cellulose, and polyethylene wax. The raw material components of the polyethylene inner pipe layer include high-density polyethylene, acrylonitrile-butadiene-styrene copolymer, toughening agent, and polyethylene wax. The raw material components of the double-layer adhesive film include polyurethane resin with a plurality of hydroxyl sites on the surface, SMA resin-modified polyethylene-ester copolymer, phytic acid-modified polyvinyl alcohol resin, initiator, and crosslinking agent; The corrosion inhibitor 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(nonylphenyl) 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 benzoyl peroxide, tert-butyl 3,5,5-trimethylhexanoate peroxide, tert-amyl benzoate peroxide, and tert-butyl 2-ethylhexyl carbonate peroxide; The crosslinking 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 includes the following steps: S1: Mix high-density polyethylene and acrylonitrile-butadiene-styrene copolymer evenly and send them into a melting device for melting. After the high-density polyethylene becomes a molten state, add the toughening agent. After all melting is completed, add polyethylene wax, extrude through a twin-screw extruder, form a core pipe after sizing through a die, and cool in advance by spraying before the core pipe enters the sizing sleeve position, and cool the sizing sleeve. After sizing, the polyethylene inner pipe layer is obtained; S2: Send the polyethylene inner pipe layer into a steel wire winding device through a tractor. First, cover a layer of adhesive film on the outer surface of the polyethylene inner pipe layer. After weaving the steel wire into a mesh on the surface of the polyethylene inner pipe layer to form a steel wire mesh, cover another layer of adhesive film, heat to the semi-molten state of the adhesive film and apply pressure to make the double-layer adhesive film fit with the polyethylene inner pipe layer and the steel wire mesh; S3: Send high-density polyethylene into a melting device for melting. After the high-density polyethylene becomes a molten state, add evenly mixed benzoyl peroxide, corrosion inhibitor, and antioxidant, keep warm and stir. After cooling by 20 °C, add carboxymethyl cellulose and polyethylene wax, and send them into a twin-screw extruder to extrude and coat on the outer surface of the double-layer adhesive film to form a polyethylene outer pipe layer. After cooling, the steel wire mesh skeleton composite pipe is obtained.

2. The preparation method of a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that, The preparation method of the double-layer adhesive film is: T1: Mix the SMA resin-modified polyethylene-ester copolymer, the polyurethane resin with multiple hydroxyl sites on the surface, and the initiator first, and send them into a melting equipment for melting. After the SMA resin-modified polyethylene-ester copolymer becomes a molten state, add the phytic acid-modified polyvinyl alcohol resin and the crosslinking agent. After all melting is completed, send it into an extruder for extrusion granulation to obtain adhesive particles. T2: Send the adhesive particles into a casting equipment, set the casting temperature at 85~110 °C, and after casting is completed, obtain a film, namely the adhesive film.

3. The preparation method of 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 is as follows: Mix the polyethylene-ester copolymer with dry magnesium hydroxide powder and carry out a melting reaction. After melting is completed, add the unsaturated SMA resin and the initiator for a melt grafting reaction. Graft the SMA resin onto the molecular chain of the polyethylene-ester copolymer through the unsaturated bonds in the unsaturated SMA resin, and extrude and granulate 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 feeding mass ratio of the polyethylene-ester copolymer to the unsaturated SMA resin is 1:0.5~1; the feeding mass ratio of the polyethylene-ester copolymer to the magnesium hydroxide powder is 1:0.8~1; the temperature of the melting 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 an interval of 2 minutes each time, and the single batch addition amount is 1 / 5 of the total amount of the initiator.

4. The preparation method of a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that, The preparation method of the SMA resin is as follows: Completely melt the SMA resin and then dropwise add an unsaturated compound containing a double bond. After the reaction is completed, obtain the unsaturated SMA resin. The unsaturated compound is selected from one or more of allyl alcohol, methallyl alcohol, maleic hydrazide, and acrylyl diamine; the feeding mass ratio of the SMA resin to the unsaturated compound is 1:0.1~0.2; the reaction temperature is 150~190 °C, and the reaction time is 1.5~2 h.

5. The preparation method of a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that, The preparation method of the polyurethane resin with multiple hydroxyl sites on the surface is as follows: React bis(ethylene oxide) with carbon dioxide in the presence of a catalyst to generate an intermediate product, and then the intermediate product reacts with diethylenetriamine to generate the polyurethane resin with multiple hydroxyl sites on the surface. The catalyst is selected from one or more of lithium chloride, sodium bromide, and sodium iodide. The feeding mass ratio of bis(ethylene oxide) to the 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 preparation method of 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 is as follows: Dissolve polyvinyl alcohol in a solution, add phytic acid and add sulfuric acid for catalysis for an esterification reaction. The product is washed with water, centrifuged and dried to obtain the phytic acid-modified polyvinyl alcohol resin.

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

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

9. The preparation method of a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that: The raw material mass parts of the double-layer adhesive film are 100 parts of SMA resin-modified polyethylene-ester copolymer, 20-35 parts of polyurethane resin with a plurality of hydroxyl sites 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 preparation method of a steel wire mesh composite polyethylene pipe according to claim 1, characterized in that, In step S2, the steel wire also undergoes a surface treatment process before being woven into a steel wire mesh. The surface treatment 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 it to 80-90 °C, wash for 5 minutes, and take out the steel wire and rinse it with tap water. E2 Rust removal and phosphating: Immerse the degreased steel wire in a mixed solution 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 triethylamine on the surface of the phosphated steel wire to seal the easily oxidized ions on the surface of the steel wire.

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