Wear-resistant plastic-coated composite steel pipe and preparation method thereof

Abstract

The invention relates to the technical field of plastic-coated steel pipes, and provides a wear-resistant plastic-coated composite steel pipe and a preparation method thereof. A wear-resistant plastic-coated composite steel pipe comprises a steel pipe body and a protective layer arranged on the outer surface of the steel pipe body, and the protective layer comprises a sintered epoxy layer, an adhesive layer and a polyethylene layer which are sequentially arranged from inside to outside; the polyethylene layer is prepared from the following components in parts by weight: 100 parts of high-density polyethylene, 4-8 parts of cellulose acetate butyrate, 10-18 parts of zirconium oxide, 4-6 parts of graphene, 4-8 parts of zinc oxide, 1-3 parts of an antioxidant and 5-8 parts of a lubricant; the zirconium oxide comprises zirconium oxide A and zirconium oxide B in a weight ratio of (1.5-4): 1; the specific surface area of the zirconia A is 40-60 m < 2 > / g, and the specific surface area of the zirconia B is 10-20 m < 2 > / g. By means of the technical scheme, the problem that in the prior art, the plastic-coated composite steel pipe is poor in wear resistance is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic - coated steel pipes, and specifically, to a wear - resistant plastic - coated composite steel pipe and a preparation method thereof. Background Art

[0002] In the fields of modern industry and infrastructure construction, plastic - coated composite steel pipes have been widely used due to their unique advantages. The plastic - coated composite steel pipe combines the high strength of the steel pipe with the corrosion - resistance, wear - resistance and other characteristics of the plastic coating, and is widely used in industries such as petrochemical, water supply and drainage, and gas transmission, effectively solving the problems of easy corrosion and short service life of traditional metal pipes.

[0003] In fields such as construction, chemical transportation, and mining, pipes need to frequently contact sand, granular materials, and corrosive chemical media. The traditional plastic - coated composite steel pipe has poor wear resistance. In these harsh environments, the surface coating is easily worn. Once the coating is damaged, the steel pipe substrate will be exposed, and then corroded, seriously affecting the structural strength and service life of the pipe, increasing the maintenance cost and potential safety hazards.

[0004] In the polyethylene coating of traditional plastic - coated composite steel pipes, polyethylene itself has a certain wear resistance, but in the face of complex and harsh working conditions, relying solely on its own characteristics is far from enough. Therefore, in order to improve the wear resistance of the polyethylene coating, the prior art generally adopts the method of adding a large amount of wear - resistant fillers. However, the large - scale addition of wear - resistant fillers not only affects the bonding force between the polyethylene coating and the steel pipe substrate, resulting in problems such as easy delamination and peeling of the coating, but also restricts the improvement effect of the overall wear - resistant performance due to poor compatibility between the materials in the polyethylene coating.

[0005] Therefore, it is of great significance to develop a wear - resistant plastic - coated composite steel pipe with good wear resistance for extending the service life of plastic - coated composite steel pipes. Summary of the Invention

[0006] The present invention provides a wear - resistant plastic - coated composite steel pipe and a preparation method thereof, which solve the problem of poor wear resistance of plastic - coated composite steel pipes in related technologies.

[0007] The technical solution of the present invention is as follows: The present invention provides a wear - resistant plastic - coated composite steel pipe, which includes a steel pipe and a protective layer provided on the outer surface of the steel pipe. The protective layer includes a fusion - bonded epoxy layer, an adhesive layer, and a polyethylene layer arranged in sequence from the inside to the outside; The raw materials of the polyethylene layer include the following components in parts by weight: 100 parts of high - density polyethylene, 4 - 8 parts of cellulose acetate butyrate, 10 - 18 parts of zirconium oxide, 4 - 6 parts of graphene, 4 - 8 parts of zinc oxide, 1 - 3 parts of antioxidant, and 5 - 8 parts of lubricant; The zirconia includes zirconia A and zirconia B with a weight ratio of 1.5 to 4:1; The specific surface area of the zirconia A is 40 to 60 m 2 / g, and the specific surface area of the zirconia B is 10 to 20 m 2 / g.

[0008] In the wear-resistant coated plastic composite steel pipe of the present invention, a protective layer of a fusion-bonded epoxy layer, an adhesive layer, and a polyethylene layer is provided on the outer surface of the steel pipe. The multi-layer structure design of the fusion-bonded epoxy layer, the adhesive layer, and the polyethylene layer enables the layers to cooperate with each other, improving the overall protection effect on the steel pipe and extending the service life of the wear-resistant coated plastic composite steel pipe.

[0009] In the polyethylene layer of the wear-resistant coated plastic composite steel pipe of the present invention, high-density polyethylene is used as the base material. High-density polyethylene itself has high linearity and regularity, and the molecular chains are arranged closely, having good chemical corrosion resistance, which can provide basic protection and support for the polyethylene layer. Combined with cellulose acetate butyrate, zirconia, graphene, zinc oxide, antioxidant, and lubricant, a polyethylene layer with a stable internal structure can be formed under the mutual cooperation of each component. As the outermost layer of the protective layer of the wear-resistant coated plastic composite steel pipe, it can effectively protect the steel pipe, extend its service life, and meet the use requirements in various harsh environments. The model of high-density polyethylene can be a conventional model in the art, for example, it can be high-density polyethylene DMDA-8008H, high-density polyethylene DMDA-6147, high-density polyethylene TR-144, and preferably high-density polyethylene DMDA-8008H.

[0010] In the polyethylene layer of the wear-resistant coated plastic composite steel pipe of the present invention, cellulose acetate butyrate can improve flexibility, enabling the wear-resistant coated plastic composite steel pipe to have certain impact resistance. When subjected to external force impact, it can better absorb and disperse energy and is not easily broken or damaged. The model of cellulose acetate butyrate can be a conventional model in the art, for example, it can be cellulose acetate butyrate CAB-171-15, cellulose acetate butyrate CAB-381-0.5, cellulose acetate butyrate CAB-381-2, cellulose acetate butyrate CAB-381-0.5, and preferably cellulose acetate butyrate CAB-381-2.

[0011] In the polyethylene layer of the wear-resistant plastic-coated composite steel pipe of the present invention, the addition of antioxidants can, to a certain extent, inhibit the oxidation reaction of the polyethylene layer during use, prevent the components of the polyethylene layer from aging and becoming brittle due to oxidation, thereby effectively extending the service life of the wear-resistant plastic-coated composite steel pipe and ensuring its good performance in the long term. The antioxidant can be any one or more antioxidants in the art. For example, it can be antioxidant 1010, antioxidant 1076, antioxidant 626, antioxidant 168, antioxidant 3114, antioxidant 1098. Preferably, they are antioxidant 1010, antioxidant 168, antioxidant 1098, and more preferably antioxidant 1010.

[0012] In the polyethylene layer of the wear-resistant plastic-coated composite steel pipe of the present invention, the addition of lubricants can improve the processing fluidity of the polyethylene layer, make the components more easily and uniformly dispersed during the mixing process, reduce the processing difficulty, and at the same time endow the polyethylene layer with basic smoothness. The lubricant can be a conventional lubricant in the art. For example, it can be a hydrocarbon lubricant or a stearate lubricant. Among them, the hydrocarbon lubricant can be polyethylene wax or oxidized polyethylene wax, and the stearate lubricant can be calcium stearate or zinc stearate. Preferably, it is polyethylene wax.

[0013] In the present invention, the weight ratio of zirconia with a specific surface area of 40 - 60 m 2 / g to zirconia with a specific surface area of 10 - 20 m 2 / g is 1.5 - 4:1. For example, it can be 1.5:1, 2:1, 3:1, 4:1. Preferably, it is 3:1. When the weight ratio is 3:1, the wear resistance of the wear-resistant plastic-coated composite steel pipe can be further improved, and the wear value of the wear-resistant plastic-coated composite steel pipe can be reduced to 0.13 mg.

[0014] As a further technical solution, the zirconia is brominated bisphenol A epoxy resin composite zirconia.

[0015] As a further technical solution, the brominated bisphenol A epoxy resin composite zirconia includes zirconia and brominated bisphenol A epoxy resin with a weight ratio of 32:2 - 7.

[0016] In the polyethylene layer of the wear-resistant plastic-coated composite steel pipe of the present invention, the zirconia is compounded with brominated bisphenol A epoxy resin. Without affecting the wear resistance of the wear-resistant plastic-coated composite steel pipe, the corrosion resistance of the wear-resistant plastic-coated composite steel pipe can be improved. The possible reason is speculated as follows: After the zirconia is compounded with brominated bisphenol A epoxy resin, the binding effect between zirconia and the organic substrate can be improved to a certain extent. This firm interfacial binding can ensure that when the polyethylene layer is subjected to external corrosion, the dense integrity of the polyethylene layer structure is maintained, thereby enhancing the protection of the steel pipe and improving the corrosion resistance of the wear-resistant plastic-coated composite steel pipe.

[0017] In the polyethylene layer of the wear-resistant plastic-coated composite steel pipe of the present invention, the raw materials of the brominated bisphenol A epoxy resin composite zirconia include zirconia and brominated bisphenol A epoxy resin, and the weight ratio of zirconia to brominated bisphenol A epoxy resin is 32:2 to 7. For example, it can be 32:2, 32:3, 32:4, 32:5, 32:6, 32:7. When the weight ratio of zirconia to brominated bisphenol A epoxy resin is 32:3 to 5, the corrosion resistance of the wear-resistant plastic-coated composite steel pipe can be further improved, so that after the wear-resistant plastic-coated composite steel pipe is treated with sulfuric acid, the impact strength retention rate is increased to more than 92%. When the weight ratio of zirconia to brominated bisphenol A epoxy resin is outside the range of 32:3 to 5, the impact strength retention rate is lower.

[0018] As a further technical solution, the preparation method of the brominated bisphenol A epoxy resin composite zirconia includes the following steps: A1. Disperse the zirconia in ethanol, add a silane coupling agent, disperse evenly, concentrate, and dry to obtain pretreated zirconia; A2. Disperse the brominated bisphenol A epoxy resin in ethyl acetate, add the pretreated zirconia, mix evenly, concentrate, and dry to obtain brominated bisphenol A epoxy resin composite zirconia.

[0019] In the present invention, the silane coupling agent can be a conventional silane coupling agent in the art. For example, it can be γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and preferably γ-glycidoxypropyltrimethoxysilane.

[0020] As a further technical solution, the addition amount of the silane coupling agent is 4% to 10% of the weight of the zirconia. For example, it can be 4%, 4.2%, 4.5%, 5%, 5.5%, 6%, 7%, 7.5%, 8%, 9%, 10%, and preferably 5%.

[0021] As a further technical solution, in step A1, when dispersing evenly, a stirring method is adopted, the stirring speed is 300 to 400 rpm. For example, it can be 300 rpm, 320 rpm, 340 rpm, 350 rpm, 360 rpm, 380 rpm, 400 rpm, and preferably 360 rpm, and the stirring time is 20 to 40 min. For example, it can be 20 min, 25 min, 30 min, 35 min, 40 min, and preferably 35 min.

[0022] As a further technical solution, in step A2, when mixing evenly, stirring is adopted, the stirring speed is 200-300 rpm, for example, it can be 200 rpm, 220 rpm, 240 rpm, 250 rpm, 280 rpm, 300 rpm, preferably 250 rpm, and the stirring time is 1.5-2.5 h, for example, it can be 1.5 h, 1.8 h, 2 h, 2.3 h, 2.5 h, preferably 2 h.

[0023] As a further technical solution, the graphene includes one or two of graphene oxide and fluorinated graphene.

[0024] As a further technical solution, when the graphene includes graphene oxide and fluorinated graphene, the weight ratio of the fluorinated graphene to the graphene oxide is 3-4:1, for example, it can be 3:1, 3.2:1, 3.5:1, 3.6:1, 4:1, preferably 3:1, 4:1, and more preferably 4:1.

[0025] Graphene itself has good stability and wear resistance. In the polyethylene layer of the wear-resistant coated plastic composite steel pipe of the present invention, the graphene includes graphene oxide and fluorinated graphene. The addition of graphene oxide and fluorinated graphene can act together with zirconia to improve the stability and wear resistance of the polyethylene layer.

[0026] As a further technical solution, the raw materials of the fusion-bonded epoxy layer include the following components in parts by weight: 50 parts of epoxy resin, 10-15 parts of ethylene-vinyl acetate copolymer, 10-15 parts of petroleum resin, 24-28 parts of titanium hydride, 2-5 parts of degassing agent, and 1-3 parts of curing agent.

[0027] In the fusion-bonded epoxy layer of the wear-resistant coated plastic composite steel pipe of the present invention, the degassing agent can be a conventional degassing agent in the art, for example, it can be benzoin, stearic acid, micro powder wax, preferably benzoin; the curing agent can be a conventional curing agent in the art, for example, it can be adipic dihydrazide, phthalic anhydride, 2-methylimidazole, preferably adipic dihydrazide.

[0028] As a further technical solution, the raw materials of the adhesive layer include the following components in parts by weight: 40 parts of ethylene acrylic resin, 8-14 parts of polyvinyl butyral, 10-20 parts of polyisobutylene, and 2-4 parts of plasticizer.

[0029] In the adhesive layer of the wear-resistant coated plastic composite steel pipe of the present invention, the plasticizer can be a conventional plasticizer in the art, for example, it can be dioctyl phthalate, butyl benzyl phthalate, dioctyl adipate, preferably dioctyl phthalate.

[0030] The present invention provides a method for preparing a wear-resistant coated composite steel pipe. To prepare the wear-resistant coated composite steel pipe, the following steps are included: S1. Mix the raw materials of the fusion-bonded epoxy layer evenly, extrude, and pulverize to obtain the fusion-bonded epoxy layer powder. S2. Mix the raw materials of the adhesive layer evenly, extrude, and pulverize to obtain the adhesive layer powder. S3. Sinter the fusion-bonded epoxy layer powder on the outer surface of the steel pipe to obtain the fusion-bonded epoxy layer, and lay the adhesive layer powder around the fusion-bonded epoxy layer to obtain the adhesive layer. S4. Mix the raw materials of the polyethylene layer evenly, extrude, lay them around the adhesive layer, and apply pressure for compounding to obtain the wear-resistant coated composite steel pipe.

[0031] The working principle and beneficial effects of the present invention are as follows: 1. In the present invention, zirconia includes zirconia A with a specific surface area of 40 - 60 m 2 / g and zirconia B with a specific surface area of 10 - 20 m 2 / g. By using two kinds of zirconia with different specific surface areas together, the wear resistance of the wear-resistant coated composite steel pipe is effectively improved. Traditional technologies mostly rely on the hardness of the wear-resistant filler itself to improve wear resistance, and by increasing the content of the wear-resistant filler to greatly improve the wear resistance of the coated composite steel pipe. This not only affects the bonding force between the polyethylene coating and the steel pipe substrate, but also limits the improvement of wear resistance due to poor compatibility between the materials in the polyethylene coating. However, the present invention pays attention to the influence of the microstructure of the wear-resistant material itself on the interface bonding of the organic substrate. By using zirconia A with a specific surface area of 40 - 60 m 2 / g and zirconia B with a specific surface area of 10 - 20 m 2 / g together, the interface bonding effect between zirconia and the organic substrate is improved, and finally the wear resistance of the wear-resistant coated composite steel pipe is improved.

[0032] 2. In the present invention, when the specific surface area of zirconia A is 40 - 60 m 2 / g and the specific surface area of zirconia B is 10 - 20 m 2 / g, their combination can effectively improve the wear resistance of the wear-resistant coated composite steel pipe. When the specific surface area of zirconia A is outside the range of 40 - 60 m 2 / g and the specific surface area of zirconia B is outside the range of 10 - 20 m 2 / g, their synergistic effect is poor, and the improvement effect on the wear resistance of the coated composite steel pipe is poor. Specific embodiments

[0033] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0034] In the following examples and comparative examples, the epoxy resin has the model number SM601; the ethylene-vinyl acetate copolymer has the model number EVA910; the petroleum resin has the model number C9 petroleum resin; the particle size of titanium hydride is 2 μm; the ethylene acrylic resin has the model number EAA3440; the polyvinyl butyral has the model number B17HX; the polyisobutene has the model number HRD850; the high-density polyethylene has the model number DMDA-8008H; the cellulose acetate butyrate has the model number CAB-381-2; the zirconia with a specific surface area of 40 m 2 / g and a particle size of 30 nm; the zirconia with a specific surface area of 60 m 2 / g and a particle size of 10 nm; the zirconia with a specific surface area of 10 m 2 / g and a particle size of 80 nm; the zirconia with a specific surface area of 20 m 2 / g and a particle size of 20 nm; the zirconia with a specific surface area of 65.16 m 2 / g and a particle size of 15 nm; the zirconia with a specific surface area of 30 m 2 / g and a particle size of 30 nm; the zirconia with a specific surface area of 8 m 2 / g and a particle size of 50 nm; the brominated bisphenol A epoxy resin has the model number NPEB-400.

[0035] Example 1 A preparation method of a wear-resistant coated composite steel pipe includes the following steps: S1. Mix 50 parts of epoxy resin, 10 parts of ethylene-vinyl acetate copolymer, 10 parts of petroleum resin, 24 parts of titanium hydride, 2 parts of benzoin, and 1 part of adipic dihydrazide evenly, extrude, and pulverize to obtain fusion-bonded epoxy layer powder; S2. Mix 40 parts of ethylene acrylic resin, 8 parts of polyvinyl butyral, 10 parts of polyisobutene, and 2 parts of dioctyl phthalate evenly, extrude, and pulverize to obtain adhesive layer powder; S3. Fusibly bond the fusion-bonded epoxy layer powder to the outer surface of the steel pipe to obtain a fusion-bonded epoxy layer, and lay the adhesive layer powder around the fusion-bonded epoxy layer to obtain an adhesive layer; S4. Mix 100 parts of high-density polyethylene, 4 parts of cellulose acetate butyrate, 6 parts of zirconia with a specific surface area of 40 m 2 / g, and 4 parts of zirconia with a specific surface area of 10 m 2Mix 3 parts of zirconia with a specific surface area of 40 m² / g, 3 parts of fluorinated graphene, 1 part of graphene oxide, 4 parts of zinc oxide, 1 part of antioxidant 168, and 5 parts of polyethylene wax evenly, extrude, lay it around the adhesive layer, and press and compound to obtain a wear-resistant plastic-coated composite steel pipe.

[0036] Example 2 A method for preparing a wear-resistant plastic-coated composite steel pipe, comprising the following steps: S1. Mix 50 parts of epoxy resin, 13 parts of ethylene-vinyl acetate copolymer, 12 parts of petroleum resin, 26 parts of titanium hydride, 3 parts of benzoin, and 2 parts of adipic dihydrazide evenly, extrude, and pulverize to obtain a fusion-bonded epoxy layer powder; S2. Mix 40 parts of ethylene acrylic resin, 10 parts of polyvinyl butyral, 15 parts of polyisobutene, and 3 parts of dioctyl phthalate evenly, extrude, and pulverize to obtain an adhesive layer powder; S3. Fusibly bond the fusion-bonded epoxy layer powder to the outer surface of the steel pipe to obtain a fusion-bonded epoxy layer, and lay the adhesive layer powder around the fusion-bonded epoxy layer to obtain an adhesive layer; S4. Mix 100 parts of high-density polyethylene, 6 parts of cellulose acetate butyrate, 12 parts of zirconia with a specific surface area of 40 m² 2 / g, 4 parts of zirconia with a specific surface area of 10 m² 2 / g, 4 parts of fluorinated graphene, 1 part of graphene oxide, 6 parts of zinc oxide, 2 parts of antioxidant 1010, and 7 parts of polyethylene wax evenly, extrude, lay it around the adhesive layer, and press and compound to obtain a wear-resistant plastic-coated composite steel pipe.

[0037] Example 3 A method for preparing a wear-resistant plastic-coated composite steel pipe, comprising the following steps: S1. Mix 50 parts of epoxy resin, 15 parts of ethylene-vinyl acetate copolymer, 15 parts of petroleum resin, 28 parts of titanium hydride, 5 parts of benzoin, and 3 parts of adipic dihydrazide evenly, extrude, and pulverize to obtain a fusion-bonded epoxy layer powder; S2. Mix 40 parts of ethylene acrylic resin, 14 parts of polyvinyl butyral, 20 parts of polyisobutene, and 4 parts of dioctyl phthalate evenly, extrude, and pulverize to obtain an adhesive layer powder; S3. Fusibly bond the fusion-bonded epoxy layer powder to the outer surface of the steel pipe to obtain a fusion-bonded epoxy layer, and lay the adhesive layer powder around the fusion-bonded epoxy layer to obtain an adhesive layer; S4. Mix 100 parts of high-density polyethylene, 8 parts of cellulose acetate butyrate, 14.4 parts of zirconia with a specific surface area of 40 m² 2 / g, 3.6 parts of zirconia with a specific surface area of 10 m² 24.8 parts of graphene fluoride, 1.2 parts of graphene oxide, 8 parts of zinc oxide, 3 parts of antioxidant 1098, and 8 parts of polyethylene wax are mixed evenly with 0 parts of zirconia with a specific surface area of 40 m² / g, extruded, laid around the adhesive layer, and pressure-compounded to obtain a wear-resistant plastic-coated composite steel pipe.

[0038] Example 4 The difference between this example and Example 2 is only that in this example, the zirconia with a specific surface area of 40 m² / g is replaced with an equal amount of zirconia with a specific surface area of 60 m² / g, and the zirconia with a specific surface area of 10 m² / g is replaced with an equal amount of zirconia with a specific surface area of 20 m² / g. 2 / g of zirconia is replaced with an equal amount of zirconia with a specific surface area of 60 m² / g, and the zirconia with a specific surface area of 10 m² / g 2 / g of zirconia is replaced with an equal amount of zirconia with a specific surface area of 20 m² / g. 2 / g of zirconia is replaced with an equal amount of zirconia with a specific surface area of 20 m² / g. 2 / g of zirconia.

[0039] Example 5 The difference between this example and Example 2 is only that in this example, the zirconia is brominated bisphenol A epoxy resin composite zirconia, and the preparation method of the brominated bisphenol A epoxy resin composite zirconia includes the following steps: A1. Disperse 24 parts of zirconia with a specific surface area of 40 m² / g and 8 parts of zirconia with a specific surface area of 10 m² / g in 40 parts of ethanol, add 1.6 parts of γ-glycidoxypropyltrimethoxysilane, stir at a stirring speed of 360 rpm for 35 min, concentrate, and dry to obtain pretreated zirconia; 2 / g of zirconia and 8 parts of zirconia with a specific surface area of 10 m² / g 2 / g of zirconia are dispersed in 40 parts of ethanol, 1.6 parts of γ-glycidoxypropyltrimethoxysilane are added, and after stirring at a stirring speed of 360 rpm for 35 min, it is concentrated and dried to obtain pretreated zirconia; A2. Disperse 2 parts of brominated bisphenol A epoxy resin in 30 parts of ethyl acetate, add the pretreated zirconia, stir at a stirring speed of 250 rpm for 2 h, concentrate, and dry to obtain brominated bisphenol A epoxy resin composite zirconia; A method for preparing a wear-resistant plastic-coated composite steel pipe includes the following steps: S1. Mix 50 parts of epoxy resin, 13 parts of ethylene-vinyl acetate copolymer, 12 parts of petroleum resin, 26 parts of titanium hydride, 3 parts of benzoin, and 2 parts of adipic dihydrazide evenly, extrude, and crush to obtain a fusion-bonded epoxy layer powder; S2. Mix 40 parts of ethylene acrylic resin, 10 parts of polyvinyl butyral, 15 parts of polyisobutylene, and 3 parts of dioctyl phthalate evenly, extrude, and crush to obtain an adhesive layer powder; S3. Fuse the fusion-bonded epoxy layer powder on the outer surface of the steel pipe to obtain a fusion-bonded epoxy layer, and lay the adhesive layer powder around the fusion-bonded epoxy layer to obtain an adhesive layer; S4. Mix 100 parts of high-density polyethylene, 6 parts of cellulose acetate butyrate, 16 parts of brominated bisphenol A epoxy resin composite zirconia, 4 parts of fluorinated graphene, 1 part of graphene oxide, 6 parts of zinc oxide, 2 parts of antioxidant 1010 and 7 parts of polyethylene wax evenly, extrude, lay it on the periphery of the adhesive layer, and press and compound to obtain a wear-resistant plastic-coated composite steel pipe.

[0040] Example 6 The difference between this example and Example 5 is only that in this example, during the preparation process of brominated bisphenol A epoxy resin composite zirconia, the addition amount of brominated bisphenol A epoxy resin is 7 parts.

[0041] Example 7 The difference between this example and Example 5 is only that in this example, during the preparation process of brominated bisphenol A epoxy resin composite zirconia, the addition amount of brominated bisphenol A epoxy resin is 3 parts.

[0042] Example 8 The difference between this example and Example 5 is only that in this example, during the preparation process of brominated bisphenol A epoxy resin composite zirconia, the addition amount of brominated bisphenol A epoxy resin is 5 parts.

[0043] Comparative Example 1 The difference between this comparative example and Example 2 is only that in this comparative example, zirconia with a specific surface area of 40 m 2 / g is replaced with an equal amount of zirconia with a specific surface area of 10 m 2 / g.

[0044] Comparative Example 2 The difference between this comparative example and Example 2 is only that in this comparative example, zirconia with a specific surface area of 10 m 2 / g is replaced with an equal amount of zirconia with a specific surface area of 40 m 2 / g.

[0045] Comparative Example 3 The difference between this comparative example and Example 2 is only that in this comparative example, no zirconia is added.

[0046] Comparative Example 4 The difference between this comparative example and Example 2 is only that in this comparative example, zirconia with a specific surface area of 40 m 2 / g is replaced with an equal amount of zirconia with a specific surface area of 65.16 m 2 / g, and zirconia with a specific surface area of 10 m 2 / g is replaced with an equal amount of zirconia with a specific surface area of 30 m 2 / g.

[0047] Comparative Example 5 The difference between this comparative example and Example 2 is only that in this comparative example, the zirconia with a specific surface area of 40 m 2 / g is replaced with an equal amount of zirconia with a specific surface area of 30 m 2 / g, and the zirconia with a specific surface area of 10 m 2 / g is replaced with an equal amount of zirconia with a specific surface area of 8 m 2 / g.

[0048] Experimental Example 1 Wear Resistance Test The wear-resistant plastic-coated composite steel pipes prepared in Examples 1-4 and Comparative Examples 1-5 were subjected to a wear test using an MMW-1G universal friction and wear testing machine, and the wear loss value was calculated according to the following formula: wear loss value (mg) = mass before wear - mass after wear. During the test, the load was 100 N, the rotation speed was 100 r / min, and the wear time was 15 min. The test results are shown in Table 1: Table 1 Wear Resistance Test Results of Examples 1-4 and Comparative Examples 1-5

[0049] Compared with Comparative Examples 1-5, the wear loss values of the wear-resistant plastic-coated composite steel pipes prepared in Examples 1-4 decreased, indicating that by adding zirconia with a specific surface area of 40-60 m 2 / g and zirconia with a specific surface area of 10-20 m 2 / g to the polyethylene layer of the wear-resistant plastic-coated composite steel pipe, the wear resistance of the wear-resistant plastic-coated composite steel pipe can be improved by using two kinds of zirconia with different specific surface areas.

[0050] Experimental Example 2 Corrosion Resistance Test The impact strength of the polyethylene layer of the wear-resistant plastic-coated composite steel pipes prepared in Example 2 and Examples 5-8 was tested according to the method specified in GB / T 1843-2008 "Plastics - Determination of Izod impact strength", with a notch of type A. Then, the samples were immersed in 30 wt% sulfuric acid for 48 h and then the impact strength after acid treatment was tested according to the above method. The specimen size was 80 mm × 10 mm and the thickness was 4 mm. The test results are shown in Table 2: Table 2 Corrosion Resistance Test Results of Example 2 and Examples 5-8

[0051] The impact strength retention rates of Examples 2, 5 to 8 were obtained according to Impact strength retention rate = Impact strength after acid treatment / Impact strength × 100%. Compared with Example 2, after the polyethylene layer of the wear-resistant plastic-coated composite steel pipe prepared in Examples 5 to 8 was treated with sulfuric acid, the impact strength retention rate increased, indicating that after the zirconia was compounded with brominated bisphenol A epoxy resin, the corrosion resistance of the wear-resistant plastic-coated composite steel pipe could be improved.

[0052] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A wear-resistant plastic-coated composite steel pipe, characterized in that, It includes a steel pipe and a protective layer provided on the outer surface of the steel pipe. The protective layer includes a fusion-bonded epoxy layer, an adhesive layer, and a polyethylene layer arranged in sequence from the inside to the outside; The raw materials of the polyethylene layer include the following components in parts by weight: 100 parts of high-density polyethylene, 4-8 parts of cellulose acetate butyrate, 10-18 parts of zirconia, 4-6 parts of graphene, 4-8 parts of zinc oxide, 1-3 parts of antioxidant, and 5-8 parts of lubricant; The zirconia includes zirconia A and zirconia B with a weight ratio of 1.5-4:1; The specific surface area of the zirconia A is 40 to 60 m 2 / g, and the specific surface area of the zirconia B is 10 to 20 m 2 / g.

2. The wear-resistant coated plastic composite steel pipe according to claim 1, wherein, The zirconia is brominated bisphenol A epoxy resin composite zirconia.

3. The wear-resistant plastic-coated composite steel pipe according to claim 2, wherein The brominated bisphenol A epoxy resin composite zirconia includes zirconia and brominated bisphenol A epoxy resin with a weight ratio of 32:2-7.

4. The wear-resistant coated plastic composite steel pipe according to claim 3, wherein The preparation method of the brominated bisphenol A epoxy resin composite zirconia includes the following steps: A1. Disperse the zirconia in ethanol, add a silane coupling agent, disperse evenly, concentrate, and dry to obtain pretreated zirconia; A2. Disperse the brominated bisphenol A epoxy resin in ethyl acetate, add the pretreated zirconia, mix evenly, concentrate and dry to obtain brominated bisphenol A epoxy resin composite zirconia.

5. A wear-resistant plastic-coated composite steel pipe according to claim 1, characterized in that, The graphene includes one or both of graphene oxide and fluorinated graphene.

6. The wear-resistant coated plastic composite steel pipe according to claim 5, wherein, When the graphene includes graphene oxide and fluorinated graphene, the weight ratio of the fluorinated graphene to the graphene oxide is 3-4:

1.

7. The wear-resistant plastic-coated composite steel pipe according to claim 1, characterized in that, The antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1098; The lubricant includes one or both of stearate lubricants and hydrocarbon lubricants.

8. A wear-resistant coated plastic composite steel pipe according to claim 1, characterized in that, The raw materials of the fusion-bonded epoxy layer include the following components in parts by weight: 50 parts of epoxy resin, 10-15 parts of ethylene-vinyl acetate copolymer, 10-15 parts of petroleum resin, 24-28 parts of titanium hydride, 2-5 parts of degassing agent, and 1-3 parts of curing agent.

9. The wear-resistant plastic-coated composite steel pipe according to claim 1, characterized in that, The raw materials of the adhesive layer include the following components in parts by weight: 40 parts of ethylene acrylic resin, 8-14 parts of polyvinyl butyral, 10-20 parts of polyisobutene, and 2-4 parts of plasticizer.

10. A preparation method of a wear-resistant plastic-coated composite steel pipe for preparing the wear-resistant plastic-coated composite steel pipe according to any one of claims 1 to 9, characterized in that, It includes the following steps: S1. Mix the raw materials of the fusion-bonded epoxy layer evenly, extrude, and crush to obtain the fusion-bonded epoxy layer powder; S2. Mix the raw materials of the adhesive layer evenly, extrude, and crush to obtain the adhesive layer powder; S3. Sinter the fusion-bonded epoxy layer powder on the outer surface of the steel pipe to obtain the fusion-bonded epoxy layer, and lay the adhesive layer powder around the fusion-bonded epoxy layer to obtain the adhesive layer; S4. Mix the raw materials of the polyethylene layer evenly, extrude, lay them around the adhesive layer, and press and compound to obtain the wear-resistant plastic-coated composite steel pipe.

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