Steel lining polyurethane composite pipe and preparation method thereof

Abstract

The invention relates to the technical field of pipeline manufacturing, and discloses a steel lining polyurethane composite pipe and a preparation method thereof.The steel lining polyurethane composite pipe comprises a seamless steel pipe base layer, a polyurethane lining layer is attached to the inner wall of a seamless steel pipe, and a nanometer transition layer is arranged between the polyurethane lining layer and the seamless steel pipe; the nano transition layer is prepared by mixing nano titanium dioxide and nano carbon fibers according to the mass ratio of 3: 1-5: 1 and adding a silane coupling agent, and the polyurethane lining layer is prepared by mixing a component A and a component B according to the mass ratio of 1.5: 1-2: 1 and reacting. The seamless steel pipe provides high strength and rigidity and can bear large pressure and external force impact, the polyurethane lining layer has good corrosion resistance and can effectively resist erosion of various chemical media, the nano transition layer enhances the binding force between the steel pipe and the polyurethane lining layer, the lining layer is prevented from falling off, and the service life of the steel pipe is prolonged. And meanwhile, the wear resistance and the aging resistance of the composite pipe are improved through the nano material.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline manufacturing, and specifically relates to a steel-lined polyurethane composite pipe and a preparation method thereof. Background Art

[0002] In many industrial fields and civil facilities, pipeline transportation plays a key role. Although traditional steel pipes have high strength and rigidity, they have obvious deficiencies in corrosion resistance, wear resistance, and heat insulation. For example, during the transportation of chemical fluids, steel pipes are extremely vulnerable to the erosion of chemical media, resulting in thinning of the pipe wall and leakage, which not only shortens the service life of the pipeline but may also cause safety accidents; in some scenarios where high-temperature or low-temperature media need to be transported, the poor heat insulation performance of steel pipes will cause a large amount of energy loss.

[0003] To solve the corrosion problem of steel pipes, some technologies adopt the method of coating an anti-corrosion coating on the surface of steel pipes, but the coating is prone to peeling, damage, etc. during long-term use and is difficult to provide long-lasting protection. Although plastic pipes have certain advantages in corrosion resistance and heat insulation, their low strength cannot withstand high pressures, restricting their application in some high-pressure environments. Therefore, developing a pipeline with high strength, excellent corrosion resistance, good wear resistance, and excellent heat insulation performance has become an urgent problem to be solved in the current pipeline technology field. Summary of the Invention

[0004] The purpose of the present invention is to propose a steel-lined polyurethane composite pipe and a preparation method thereof in order to solve the above problems.

[0005] In order to achieve the above purpose, the present invention adopts the following technical scheme: A steel-lined polyurethane composite pipe includes a seamless steel pipe base layer, a polyurethane inner lining layer is adhered to the inner wall of the seamless steel pipe, and a nano-transition layer is provided between the polyurethane inner lining layer and the seamless steel pipe; The nano-transition layer is made by mixing nano-titanium dioxide and nano-carbon fiber in a mass ratio of 3:1 - 5:1 and adding a silane coupling agent; The polyurethane inner lining layer is made by mixing component A and component B in a mass ratio of 1.5:1 - 2:1 for reaction. Component A is a mixture of polyether polyol, chain extender, and catalyst. The chain extender is 1,4-butanediol, and the catalyst is dibutyltin dilaurate. The mass ratio of polyether polyol, 1,4-butanediol, and dibutyltin dilaurate is 100:8 - 12:0.5 - 1.5. Component B is a polyisocyanate, and the polyisocyanate is toluene diisocyanate (TDI) or hexamethylene diisocyanate (HDI).

[0006] Further, the added mass of the silane coupling agent in the nano-transition layer is 1%-3% of the total mass of the nano-titanium dioxide and the nano-carbon fiber.

[0007] Further, before the seamless steel pipe is combined with the polyurethane inner lining layer, the inner wall is treated by shot blasting, and the roughness reaches Ra12.5-Ra25μm.

[0008] Further, the particle size of the nano-titanium dioxide is 20-50nm, and the length of the nano-carbon fiber is 5-15μm.

[0009] Further, the hydroxyl value of the polyether polyol is 300-500mgKOH / g, and the molecular weight is 2000-4000.

[0010] A method for preparing a steel-lined polyurethane composite pipe includes the following steps: S1: Select a seamless steel pipe, treat its inner wall by shot blasting to make the inner wall roughness reach Ra12.5-Ra25μm, then put the steel pipe into a heating furnace and preheat it at 200-250°C for 30-60 minutes; S2: Weigh nano-titanium dioxide and nano-carbon fiber according to a mass ratio of 3:1-5:1, add them to anhydrous ethanol and ultrasonically disperse for 30-60 minutes, then add a silane coupling agent with a mass of 1%-3% of the total mass of the nano-particles, stir and react for 2-3 hours, spray the reacted mixture on the inner wall of the preheated seamless steel pipe, and dry it at 80-100°C for 2-3 hours; S3: Weigh components A and B according to a mass ratio of 1.5:1-2:1 respectively. First, add polyether polyol, 1,4-butanediol and dibutyltin dilaurate to a reaction kettle, stir and mix evenly at 80-100°C to obtain component A. Heat components A and B to 40-60°C respectively, then add component A to component B, and react under stirring conditions for 5-10 minutes to obtain a polyurethane prepolymer; S4: Pour the prepared polyurethane prepolymer into the seamless steel pipe with a nano-transition layer, rotate the steel pipe to make the polyurethane prepolymer distributed on the inner wall, and then cure it at 100-120°C for 3-5 hours to form a polyurethane inner lining layer, and obtain a steel-lined polyurethane composite pipe.

[0011] Further, in the nano-transition layer preparation step, the power of ultrasonic dispersion is 200-400W.

[0012] Further, in the polyurethane inner lining layer preparation step, the stirring speed is 800-1200r / min.

[0013] Further, in the composite pipe forming step, the rotation speed of the rotating steel pipe is 10-30r / min.

[0014] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows: 1. The seamless steel pipe in this application provides high strength and rigidity, and can withstand large pressures and external force impacts. The polyurethane inner lining layer has good corrosion resistance and can effectively resist the erosion of various chemical media; its wear resistance is excellent, which can reduce the wear of the medium on the pipe wall during transportation and extend the service life of the pipeline. The nano-transition layer enhances the bonding force between the steel pipe and the polyurethane inner lining layer, preventing the inner lining layer from falling off. At the same time, the nano-material improves the wear resistance and anti-aging performance of the composite pipe.

[0015] 2. The polyurethane in this application has a low thermal conductivity. As the inner lining layer, it can effectively reduce the heat loss during the pipeline transportation. When transporting high-temperature or low-temperature media, the energy loss is greatly reduced, achieving good heat preservation and energy-saving effects.

[0016] 3. The composite pipe in this application has good comprehensive performance and can be widely used in many fields such as chemical industry, petroleum, heat, water supply and drainage, etc., to meet the pipeline transportation requirements under different working conditions. Specific Embodiments

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0018] Embodiment 1

[0019] Pretreatment of seamless steel pipe: Select a seamless steel pipe with a specification of DN100, and perform shot blasting on its inner wall to make the roughness reach Ra12.5μm. Then put the steel pipe into a heating furnace and preheat it at 200°C for 30 minutes.

[0020] Preparation of nano-transition layer: Weigh 3g of nano-titanium dioxide and 1g of nano-carbon fiber, add them to 50mL of anhydrous ethanol, and ultrasonically disperse for 30 minutes. Add 0.04g of silane coupling agent and stir and react for 2 hours. Spray the mixed solution on the inner wall of the preheated steel pipe and dry it at 80°C for 2 hours.

[0021] Preparation of polyurethane inner lining layer: Weigh 100g of polyether polyol, 8g of 1,4-butanediol, and 0.5g of dibutyltin dilaurate and add them to a reaction kettle. Stir and mix evenly at 80°C to obtain component A. Weigh 66.7g of toluene diisocyanate (TDI) as component B. Heat components A and B to 40°C respectively, slowly add component A to component B, and stir and react at high speed for 5 minutes to obtain a polyurethane prepolymer.

[0022] Composite pipe forming: Pour the polyurethane prepolymer into the steel pipe with a nano-transition layer, rotate the steel pipe to make it evenly distributed, and cure it at 100 °C for 3 hours to obtain a steel-lined polyurethane composite pipe.

[0023] Example 2

[0024] Seamless steel pipe pretreatment: Select a seamless steel pipe with a specification of DN150, perform shot blasting treatment to make the inner wall roughness reach Ra20μm, and preheat it at 230 °C for 45 minutes.

[0025] Preparation of nano-transition layer: Weigh 4g of nano-titanium dioxide and 1g of nano-carbon fiber, add 60mL of anhydrous ethanol and ultrasonically disperse for 45 minutes, add 0.05g of silane coupling agent and stir for reaction for 2.5 hours. Spray it on the inner wall of the steel pipe and dry it at 90 °C for 2.5 hours.

[0026] Preparation of polyurethane lining layer: Mix 100g of polyether polyol, 10g of 1,4-butanediol, and 1g of dibutyltin dilaurate to obtain component A, and 80g of hexamethylene diisocyanate (HDI) as component B. Heat components A and B to 50 °C, add A to B and stir for reaction for 8 minutes to obtain a polyurethane prepolymer.

[0027] Composite pipe forming: Pour the prepolymer into the steel pipe, rotate and distribute it, and cure it at 110 °C for 4 hours to make a composite pipe.

[0028] Example 3

[0029] Seamless steel pipe pretreatment: Select a DN200 seamless steel pipe, perform shot blasting treatment until the roughness Ra is 25μm, and preheat it at 250 °C for 60 minutes.

[0030] Preparation of nano-transition layer: Weigh 5g of nano-titanium dioxide and 1g of nano-carbon fiber, add 70mL of anhydrous ethanol and ultrasonically disperse for 60 minutes, add 0.06g of silane coupling agent and stir for reaction for 3 hours. After spraying, dry it at 100 °C for 3 hours.

[0031] Preparation of polyurethane lining layer: Make component A from 100g of polyether polyol, 12g of 1,4-butanediol, and 1.5g of dibutyltin dilaurate, and 100g of toluene diisocyanate (TDI) as component B. Heat components A and B to 60 °C, mix and stir for reaction for 10 minutes to obtain a polyurethane prepolymer.

[0032] Composite pipe forming: Pour the prepolymer into the steel pipe, rotate it evenly, and cure it at 120 °C for 5 hours to obtain a composite pipe.

[0033] Comparative Example 1 Compared with Example 2, without preparing the nano-transition layer, directly prepare the polyurethane lining layer on the inner wall of the pretreated seamless steel pipe, and keep other conditions and steps unchanged.

[0034] Comparative Example 2 Compared with Example 3, the dosage of 1,4-butanediol in Component A of the polyurethane inner lining layer was reduced to 5 g, and other conditions and steps remained unchanged.

[0035] Performance Tests Bonding Strength Test: According to relevant standards, the tensile test method was used to test the bonding strength between the polyurethane inner lining layer and the seamless steel pipe, and the result was expressed in MPa.

[0036] Corrosion Resistance Test: The composite pipe sample was immersed in a hydrochloric acid solution with a mass fraction of 10%. After 72 hours of immersion, the corrosion condition of the pipe wall was observed, and the wall thickness loss was measured, expressed in mm.

[0037] Wear Resistance Test: Using an abrasive wear testing machine, the inner wall of the composite pipe was subjected to a wear test, and the wear amount was measured after the test, expressed in g.

[0038] Thermal Insulation Performance Test: By measuring the temperature difference between the inner and outer walls of the composite pipe, the thermal conductivity was calculated, expressed in W / (m・K).

[0039] The steel-lined polyurethane composite pipes prepared in Examples 1-3 are superior to Comparative Example 1 and Comparative Example 2 in terms of bonding strength, corrosion resistance, wear resistance, and thermal insulation performance. The presence of the nano-transition layer in the examples significantly improves the bonding strength and comprehensive performance of the composite pipes, and the appropriate polyurethane inner lining layer formula also has an important impact on the performance of the composite pipes.

[0040] The above description of the embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A steel-lined polyurethane composite pipe, characterized in that, It includes a seamless steel pipe base layer, and a polyurethane inner lining layer is attached to the inner wall of the seamless steel pipe. A nano-transition layer is provided between the polyurethane inner lining layer and the seamless steel pipe; The nano-transition layer is made by mixing nano-titanium dioxide and nano-carbon fiber in a mass ratio of 3:1 - 5:1 and adding a silane coupling agent; The polyurethane inner lining layer is made by mixing component A and component B in a mass ratio of 1.5:1 - 2:1 and reacting. Component A is a mixture of polyether polyol, chain extender and catalyst. The chain extender is 1,4-butanediol, and the catalyst is dibutyltin dilaurate. The mass ratio of polyether polyol, 1,4-butanediol, and dibutyltin dilaurate is 100:8 - 12:0.5 - 1.

5. Component B is a polyisocyanate, and the polyisocyanate is toluene diisocyanate (TDI) or hexamethylene diisocyanate (HDI).

2. A steel-lined polyurethane composite pipe according to claim 1, characterized in that, The added mass of the silane coupling agent in the nano-transition layer is 1% - 3% of the total mass of nano-titanium dioxide and nano-carbon fiber.

3. A steel-lined polyurethane composite pipe according to claim 1, characterized in that, Before the seamless steel pipe is combined with the polyurethane inner lining layer, its inner wall is treated by shot blasting, and the roughness reaches Ra12.5 - Ra25μm.

4. A steel-lined polyurethane composite pipe according to claim 1, characterized in that, The particle size of the nano-titanium dioxide is 20 - 50nm, and the length of the nano-carbon fiber is 5 - 15μm.

5. A steel-lined polyurethane composite pipe according to claim 1, characterized in that, The hydroxyl value of the polyether polyol is 300 - 500mgKOH / g, and the molecular weight is 2000 - 4000.

6. A method for preparing a steel-lined polyurethane composite pipe according to any one of claims 1-5, characterized in that, It includes the following steps: S1: Select a seamless steel pipe, treat its inner wall by shot blasting to make the inner wall roughness reach Ra12.5 - Ra25μm, then put the steel pipe into a heating furnace and preheat it at 200 - 250°C for 30 - 60 minutes; S2: Weigh nano-titanium dioxide and nano-carbon fiber according to a mass ratio of 3:1 - 5:1, add them to anhydrous ethanol and ultrasonically disperse for 30 - 60 minutes, then add a silane coupling agent with a mass of 1% - 3% of the total mass of nano-particles, stir and react for 2 - 3 hours, spray the reacted mixed solution on the inner wall of the preheated seamless steel pipe, and dry it at 80 - 100°C for 2 - 3 hours; S3: Weigh component A and component B according to a mass ratio of 1.5:1 - 2:1 respectively. First, add polyether polyol, 1,4-butanediol and dibutyltin dilaurate to a reaction kettle, stir and mix evenly at 80 - 100°C to obtain component A. Heat component A and component B to 40 - 60°C respectively, then add component A to component B, and react under stirring conditions for 5 - 10 minutes to obtain a polyurethane prepolymer; S4: Pour the prepared polyurethane prepolymer into the seamless steel pipe with a nano-transition layer, rotate the steel pipe to make the polyurethane prepolymer distribute on the inner wall, and then cure it at 100 - 120°C for 3 - 5 hours to form a polyurethane inner lining layer, and obtain a steel-lined polyurethane composite pipe.

7. The preparation method of a steel-lined polyurethane composite pipe according to claim 6, characterized in that, In the preparation step of the nano-transition layer, the power of ultrasonic dispersion is 200 - 400W.

8. The preparation method of a steel-lined polyurethane composite pipe according to claim 6, characterized in that, In the preparation step of the polyurethane inner lining layer, the rotation speed of stirring is 800 - 1200r / min.

9. The preparation method of a steel-lined polyurethane composite pipe according to claim 6, characterized in that, In the forming step of the composite pipe, the rotation speed of the rotating steel pipe is 10 - 30r / min.