Formula and preparation method of high-strength corrosion-resistant CPVC (Chlorinated Polyvinyl Chloride) pipe

Abstract

The invention discloses a high-strength corrosion-resistant CPVC pipe formula and a preparation method thereof. The high-strength corrosion-resistant CPVC pipe formula comprises CPVC resin, a stabilizer, a plasticizer, a lubricant, an impact modifier, a filler, color master batch and nano silicon dioxide. The method comprises the following steps: 1, preparing raw materials; step 2, premixing treatment; step 3, plasticizing extrusion; step 4, cooling and shaping; step 5, cutting detection; step 6, carrying out surface pretreatment; step 7, primer coating; step 8, coating a finishing coat; according to the invention, the nano silicon dioxide is added into a traditional CPVC pipe formula, and after blending, the nano silicon dioxide is well combined with a matrix, so that the strength of the pipe is enhanced; oil stains and impurities left on the surface are removed through surface pretreatment, and the production qualification rate of the pipe is guaranteed; and during surface treatment, epoxy primer and fluorocarbon finish paint are sequentially coated to provide an additional protection layer for the pipe, so that the aging speed is slowed down, the corrosion resistance is improved, and the service life of the pipe is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of CPVC pipes, in particular to a high-strength, corrosion-resistant CPVC pipe formula and a preparation method thereof. Background Art

[0002] Chlorinated polyvinyl chloride pipes are also called CPVC pipes. The operating temperature of CPVC pipes can be much higher than that of PVC pipes. At the same time, CPVC materials themselves are self-extinguishing and not easy to burn. They are suitable for places with fire protection requirements. The materials themselves meet the drinking water hygiene standards and are suitable for conveying drinking water. CPVC pipes can also be installed by hot melt welding, socket connection, etc., which is easy and quick to operate. Due to its excellent material properties, it is widely used in chemical, construction and other industries. The existing CPVC pipe formula and preparation process can basically meet the daily use needs, but there are still certain shortcomings. First, the existing CPVC pipes are limited by traditional formulas, which affects the strength of the prepared pipes. Second, the corrosion resistance of the pipes mainly depends on the characteristics of the material itself. As the use time increases, the aging of the material will cause the corrosion resistance of the pipes to weaken, thereby shortening the service life of the pipes. Third, the surface treatment process for the pipes in the later stage is simple, and the residual oil and impurities on the surface are easy to affect the qualified rate of the surface treatment process. Therefore, it is necessary to design a high-strength and corrosion-resistant CPVC pipe formula and its preparation method. Summary of the invention

[0003] The object of the present invention is to provide a high-strength corrosion-resistant CPVC pipe formula and a preparation method thereof to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a high-strength corrosion-resistant CPVC pipe formula, the formula comprising: CPVC resin, stabilizer, plasticizer, lubricant, impact modifier, filler, masterbatch and nano-silicon dioxide; the weight proportions of each component are: 80-90 parts of CPVC resin, 1-3 parts of stabilizer, 2-4 parts of plasticizer, 3-5 parts of lubricant, 1-3 parts of impact modifier, 8-12 parts of filler, 2-3 parts of masterbatch and 15-20 parts of nano-silicon dioxide.

[0005] As a further technical solution of the present invention, the nano silicon dioxide is prepared by hydrolysis and condensation reaction with tetraethyl orthosilicate as a precursor; and the preparation process of the nano silicon dioxide is as follows: firstly, tetraethyl orthosilicate is dissolved in anhydrous ethanol, then stirred at a stirring speed of 45 to 60 r / min, and deionized water and a hydrochloric acid solution with a concentration of 10% are added dropwise to the solution during the stirring process to initiate the hydrolysis reaction of tetraethyl orthosilicate, and after 10 to 15 minutes, the stirring speed is 35 to 40 r / min to promote the condensation of the hydrolysis product to form a stable sol, and then the sol is placed at a temperature of 35 to 38° C. to age and gel, and finally the aged sol is placed at -5 to -3° C. for freeze drying for 30 to 45 minutes, and after freeze drying, it is calcined at a temperature of 300 to 350° C. to remove residual organic matter and moisture, so as to obtain the nano silicon dioxide.

[0006] A method for preparing a high-strength, corrosion-resistant CPVC pipe comprises the following steps: step 1, raw material preparation; step 2, premixing treatment; step 3, plasticizing and extruding; step 4, cooling and shaping; step 5, cutting and testing; step 6, surface pretreatment; step 7, primer coating; step 8, topcoat coating;

[0007] In the above step 1, 80-90 parts of CPVC resin, 1-3 parts of stabilizer, 2-4 parts of plasticizer, 3-5 parts of lubricant, 1-3 parts of impact modifier, 8-12 parts of filler, 2-3 parts of masterbatch and 15-20 parts of nano-silicon dioxide are weighed according to the weight of each group and set aside;

[0008] In the above step 2, the CPVC resin, stabilizer, plasticizer, lubricant, impact modifier, filler, masterbatch and nano-silicon dioxide prepared in the above step 1 are respectively placed in a high-speed mixer, and mixed at high speed in the high-speed mixer to obtain a mixed raw material for standby use;

[0009] In the above step 3, the mixed raw material prepared in the above step 2 is put into a twin-screw extruder for plasticization and extrusion, and after plasticization and extrusion, it is filled into a tube-shaped mold for molding to obtain a tube blank for standby use;

[0010] In the above step 4, after demoulding, the tube blank prepared in the above step 3 is cooled in multiple stages to obtain the original tube for standby use;

[0011] In the above step 5, the original pipe obtained in the above step 4 is cut, and an appearance inspection is performed after the cutting process. After the inspection, a standard pipe is obtained for standby use;

[0012] In the above step 6, the standard pipe obtained in the above step 5 is cleaned with a solvent, then rinsed with clean water, polished with sandpaper after rinsing, and then cleaned and dried to obtain a clean pipe for standby use;

[0013] In the above step 7, a spray gun is used to evenly spray the primer on the clean pipe obtained in the above step 6, and the primer is placed in a constant temperature chamber for drying after spraying;

[0014] In the above step eight, a layer of topcoat is sprayed on the primer in the above step seven to obtain a high-strength, corrosion-resistant CPVC pipe.

[0015] As a further technical solution of the present invention, in the step 2, during the high-speed mixing in the high-speed mixer, the stirring speed in the mixer is 300-450 r / min, and the high-speed mixing time is 10-20 min, and the temperature in the high-speed mixer during the mixing process is 80-100° C.

[0016] As a further technical solution of the present invention, in the step three, the screw diameter of the twin-screw extruder used for plasticizing extrusion is 45-90 mm, and the screw aspect ratio L / D specification is 24-32; the screw speed during the extrusion process is 200-300 r / min, the temperature of the hopper section of the twin-screw extruder is 130-135°C, the temperature of the homogenizing section is 160-180°C, the temperature of the metering section is 180-200°C, and the temperature of the extruder head is 190-210°C, and the extrusion pressure is 10-20 MPa.

[0017] As a further technical solution of the present invention, in step four, the initial cooling stage of the multi-stage cooling uses a cold water tank, and the water temperature in the cold water tank is 10-15°C, the intermediate cooling stage uses cold water for spraying treatment, and the temperature of the cold water used in the spraying treatment is 20-25°C, and the final cooling stage is air cooling to reduce the temperature to 25-38°C.

[0018] As a further technical solution of the present invention, in step five, the cutting line speed during the cutting process is 1 to 2.4 m / min; and the appearance inspection after cutting includes bubble, crack and color difference inspection on the surface of the pipe and dimensional inspection of the outer diameter, wall thickness and other dimensions of the pipe.

[0019] As a further technical solution of the present invention, in step six, the solvent used in the process of using solvent to clean the pipe is acetone, and the time for rinsing with clean water is 2 to 3 minutes. The temperature during drying is 60 to 63°C, and the drying time is 20 to 40 minutes.

[0020] As a further technical solution of the present invention, in step seven, the spray primer is epoxy primer, and the spray thickness of the primer is 20 to 30 μm, the temperature during drying in a constant temperature chamber is 38 to 45° C., and the drying time is 120 to 150 minutes.

[0021] As a further technical solution of the present invention, in step eight, the topcoat selected is fluorocarbon topcoat. Before spraying, the fluorocarbon topcoat is placed in a mixer and a diluent is added at a stirring speed of 30 to 45 r / min to adjust the spraying viscosity. The topcoat is then applied with a spray gun to a coating thickness of 30 to 50 μm. After spraying, the topcoat is allowed to stand at room temperature for 1440 to 1500 min.

[0022] Compared with the prior art, the invention has the following beneficial effects: the high-strength corrosion-resistant CPVC pipe formula and preparation method thereof use nano silicon dioxide formed by hydrolysis and condensation reaction of tetraethyl orthosilicate as a precursor and added as an auxiliary material to the traditional CPVC pipe formula, and can maintain good bonding with the matrix resin after blending to generate a solid interface layer, thereby enhancing the strength of the prepared pipe; before coating, acetone is used as a solvent to clean the pipe surface, and then the surface of the pipe is cleaned and dried to remove the oil and impurities remaining on the surface of the pipe, thereby avoiding affecting the subsequent spraying process and ensuring the production qualification rate of the pipe; in the process of surface treatment, epoxy primer and fluorocarbon topcoat are sequentially coated to form a double-layer coating protection structure, and at the same time, the bonding strength of the fluorocarbon topcoat is increased by the primer, and the topcoat is prevented from falling off, providing an additional protective layer for the pipe, slowing down the aging speed of the pipe, further improving the corrosion resistance and extending the service life of the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] See also Figure 1 , the present invention provides a technical solution:

[0026] Embodiment 1:

[0027] A high-strength corrosion-resistant CPVC pipe formula, the formula includes: CPVC resin, stabilizer, plasticizer, lubricant, impact modifier, filler, masterbatch and nano silicon dioxide; the weight proportions of each component are: 90 parts of CPVC resin, 3 parts of stabilizer, 4 parts of plasticizer, 5 parts of lubricant, 3 parts of impact modifier, 12 parts of filler, 3 parts of masterbatch and 20 parts of nano silicon dioxide; the nano silicon dioxide is prepared by hydrolysis and condensation reaction with tetraethyl orthosilicate as a precursor; and the preparation process of the nano silicon dioxide is: firstly dissolving tetraethyl orthosilicate in anhydrous ethanol, then evaporating the mixture at 45-60 r / min. The solution is stirred at a stirring speed of , and deionized water and a 10% hydrochloric acid solution are added dropwise to the solution during the stirring process to initiate the hydrolysis reaction of ethyl orthosilicate. After 10 to 15 minutes, the solution is stirred at a stirring speed of 35 to 40 r / min to promote condensation of the hydrolysis product to form a stable sol. The sol is then placed at a temperature of 35 to 38° C. to age and gelate. Finally, the aged sol is placed at -5 to -3° C. for freeze drying for 30 to 45 minutes. After freeze drying, the sol is calcined at a temperature of 300 to 350° C. to remove residual organic matter and moisture, thereby obtaining nano silicon dioxide.

[0028] A method for preparing a high-strength, corrosion-resistant CPVC pipe comprises the following steps: step 1, raw material preparation; step 2, premixing treatment; step 3, plasticizing and extruding; step 4, cooling and shaping; step 5, cutting and testing; step 6, surface pretreatment; step 7, primer coating; step 8, topcoat coating;

[0029] In the above step 1, 90 parts of CPVC resin, 3 parts of stabilizer, 4 parts of plasticizer, 5 parts of lubricant, 3 parts of impact modifier, 12 parts of filler, 3 parts of masterbatch and 20 parts of nano-silicon dioxide are weighed according to the weight of each group and set aside;

[0030] In the above step 2, the CPVC resin, stabilizer, plasticizer, lubricant, impact modifier, filler, masterbatch and nano-silica prepared in the above step 1 are respectively placed in a high-speed mixer, and high-speed mixing is performed in the high-speed mixer to obtain a mixed raw material for standby use; during the high-speed mixing in the high-speed mixer, the stirring speed in the mixer is 450r / min, and the high-speed mixing time is 20min, and the temperature in the high-speed mixer during the mixing process is 100°C;

[0031] In the above step 3, the mixed raw material prepared in the above step 2 is put into a twin-screw extruder for plasticizing and extruding, and after plasticizing and extruding, it is filled into a tube-shaped mold for molding to obtain a tube blank for standby use; the screw diameter of the twin-screw extruder used for plasticizing and extruding is 90 mm, and the screw aspect ratio L / D specification is 32; the screw speed during the extrusion process is 300 r / min, the temperature of the hopper section of the twin-screw extruder is 135° C., the temperature of the homogenizing section is 180° C., the temperature of the metering section is 200° C., and the temperature of the extruder head is 210° C., and the extrusion pressure is 20 MPa;

[0032] In the above step 4, after demoulding, the pipe blank prepared in the above step 3 is subjected to multi-stage cooling to obtain the original pipe after cooling for standby use; the initial cooling stage of the multi-stage cooling uses a cold water tank, and the water temperature in the cold water tank is 15°C, the intermediate cooling stage uses cold water for spraying treatment, and the cold water temperature used in the spraying treatment process is 25°C, and the final cooling stage is air cooling to reduce the temperature to 38°C;

[0033] In the above step 5, the original pipe obtained in the above step 4 is cut, and an appearance inspection is performed after the cutting process. After the inspection, a standard pipe is obtained and set aside; the cutting line speed during the cutting process is 2.4m / min; and the appearance inspection after the cutting includes the inspection of bubbles, cracks and color difference on the surface of the pipe, and the outer diameter, wall thickness and other dimensions of the pipe;

[0034] In the above step 6, the standard pipe obtained in the above step 5 is cleaned with a solvent, then rinsed with clean water, polished with sandpaper after rinsing, and then cleaned and dried to obtain a clean pipe for standby use; the solvent used in the process of cleaning the pipe with a solvent is acetone, and the time for rinsing with clean water is 3 minutes, the temperature during drying is 63°C, and the drying time is 40 minutes;

[0035] In the above step 7, a spray gun is used to evenly spray the primer on the clean pipe obtained in the above step 6, and the primer is placed in a constant temperature chamber for drying after spraying; the spray primer is an epoxy primer, and the spray thickness of the primer is 30 μm. The temperature during the drying process in the constant temperature chamber is 45° C., and the drying time is 150 minutes;

[0036] In the above step eight, a layer of topcoat is sprayed on the primer in the above step seven to obtain a high-strength, corrosion-resistant CPVC pipe; the topcoat selected is fluorocarbon topcoat, and before spraying, the fluorocarbon topcoat is placed in a mixer and a diluent is added at a stirring speed of 45r / min to adjust the spraying viscosity, and then the topcoat is applied with a spray gun to a coating thickness of 50μm. After spraying, it is left to stand at room temperature for 1500min.

[0037] Embodiment 2:

[0038] A high-strength corrosion-resistant CPVC pipe formula, comprising: CPVC resin, stabilizer, plasticizer, lubricant, impact modifier, filler, masterbatch and nano-silicon dioxide; the weight proportions of the components are: 80 parts of CPVC resin, 1 part of stabilizer, 2 parts of plasticizer, 3 parts of lubricant, 1 part of impact modifier, 8 parts of filler, 2 parts of masterbatch and 15 parts of nano-silicon dioxide; the nano-silicon dioxide is prepared by hydrolysis and condensation reaction with tetraethyl orthosilicate as a precursor; and the preparation process of the nano-silicon dioxide is: firstly dissolving tetraethyl orthosilicate in anhydrous ethanol, then heating the mixture at 45-60 r / min. The stirring speed is set to stir the solution, and deionized water and a 10% hydrochloric acid solution are added dropwise to the solution during the stirring process to initiate the hydrolysis reaction of ethyl orthosilicate. After 10 to 15 minutes, the solution is stirred at a stirring speed of 35 to 40 r / min to promote condensation of the hydrolysis product to form a stable sol. The sol is then placed at a temperature of 35 to 38° C. to age and gelate. Finally, the aged sol is placed at -5 to -3° C. for freeze drying for 30 to 45 minutes. After freeze drying, the solution is calcined at a temperature of 300 to 350° C. to remove residual organic matter and moisture, thereby obtaining nano silicon dioxide.

[0039] A method for preparing a high-strength, corrosion-resistant CPVC pipe comprises the following steps: step 1, raw material preparation; step 2, premixing treatment; step 3, plasticizing and extruding; step 4, cooling and shaping; step 5, cutting and testing; step 6, surface pretreatment; step 7, primer coating; step 8, topcoat coating;

[0040] In the above step 1, 80 parts of CPVC resin, 1 part of stabilizer, 2 parts of plasticizer, 3 parts of lubricant, 1 part of impact modifier, 8 parts of filler, 2 parts of masterbatch and 15 parts of nano-silicon dioxide are weighed according to the weight of each group and set aside;

[0041] In the above step 2, the CPVC resin, stabilizer, plasticizer, lubricant, impact modifier, filler, masterbatch and nano-silica prepared in the above step 1 are respectively put into a high-speed mixer, and high-speed mixing is performed in the high-speed mixer to obtain a mixed raw material for standby use; during the high-speed mixing in the high-speed mixer, the stirring speed in the mixer is 300r / min, and the high-speed mixing time is 10min, and the temperature in the high-speed mixer during the mixing process is 80°C;

[0042] In the above step 3, the mixed raw material prepared in the above step 2 is put into a twin-screw extruder for plasticizing and extruding, and after plasticizing and extruding, it is filled into a tube-shaped mold for molding to obtain a tube blank for standby use; the screw diameter of the twin-screw extruder used for plasticizing and extruding is 45 mm, and the screw aspect ratio L / D specification is 24; the screw speed during the extrusion process is 200 r / min, the temperature of the hopper section of the twin-screw extruder is 130° C., the temperature of the homogenizing section is 160° C., the temperature of the metering section is 180° C., and the temperature of the extruder head is 190° C., and the extrusion pressure is 10 MPa;

[0043] In the above step 4, after demoulding, the pipe blank prepared in the above step 3 is subjected to multi-stage cooling to obtain the original pipe after cooling for standby use; the initial cooling stage of the multi-stage cooling uses a cold water tank, and the water temperature in the cold water tank is 10°C, the intermediate cooling stage uses cold water for spraying treatment, and the cold water temperature used in the spraying treatment process is 20°C, and the final cooling stage is air cooling to reduce the temperature to 25°C;

[0044] In the above step 5, the original pipe obtained in the above step 4 is cut, and an appearance inspection is performed after the cutting process. After the inspection, a standard pipe is obtained and set aside; the cutting line speed during the cutting process is 1m / min; and the appearance inspection after the cutting includes the inspection of bubbles, cracks and color difference on the surface of the pipe, and the outer diameter, wall thickness and other dimensions of the pipe;

[0045] In the above step 6, the standard pipe obtained in the above step 5 is cleaned with a solvent, then rinsed with clean water, polished with sandpaper after rinsing, and then cleaned and dried to obtain a clean pipe for standby use; the solvent used in the process of cleaning the pipe with a solvent is acetone, and then the time for rinsing with clean water is 2 minutes, the temperature during drying is 60°C, and the drying time is 20 minutes;

[0046] In the above step 7, a spray gun is used to evenly spray the primer on the clean pipe obtained in the above step 6, and the primer is placed in a constant temperature chamber for drying after spraying; the spray primer is an epoxy primer, and the spray thickness of the primer is 20 μm. The temperature during the drying process in the constant temperature chamber is 38° C., and the drying time is 120 minutes;

[0047] In the above step eight, a layer of topcoat is sprayed on the primer in the above step seven to obtain a high-strength corrosion-resistant CPVC pipe; the topcoat selected is fluorocarbon topcoat, and before spraying, the fluorocarbon topcoat is placed in a mixer and a diluent is added at a stirring speed of 30r / min to adjust the spraying viscosity, and then the topcoat is applied with a spray gun to a coating thickness of 30μm. After spraying, it is allowed to stand at room temperature for 1440min.

[0048] Embodiment 3:

[0049] A high-strength corrosion-resistant CPVC pipe formula, comprising: CPVC resin, stabilizer, plasticizer, lubricant, impact modifier, filler, masterbatch and nano-silicon dioxide; the weight proportions of the components are: 90 parts of CPVC resin, 1 part of stabilizer, 4 parts of plasticizer, 3 parts of lubricant, 3 parts of impact modifier, 8 parts of filler, 3 parts of masterbatch and 15 parts of nano-silicon dioxide; the nano-silicon dioxide is prepared by hydrolysis and condensation reaction with tetraethyl orthosilicate as a precursor; and the preparation process of the nano-silicon dioxide is: firstly dissolving tetraethyl orthosilicate in anhydrous ethanol, then heating the mixture at 45-60 r / min. The stirring speed is set to stir the solution, and deionized water and a 10% hydrochloric acid solution are added dropwise to the solution during the stirring process to initiate the hydrolysis reaction of ethyl orthosilicate. After 10 to 15 minutes, the solution is stirred at a stirring speed of 35 to 40 r / min to promote condensation of the hydrolysis product to form a stable sol. The sol is then placed at a temperature of 35 to 38° C. to age and gelate. Finally, the aged sol is placed at -5 to -3° C. for freeze drying for 30 to 45 minutes. After freeze drying, the solution is calcined at a temperature of 300 to 350° C. to remove residual organic matter and moisture, thereby obtaining nano silicon dioxide.

[0050] A method for preparing a high-strength, corrosion-resistant CPVC pipe comprises the following steps: step 1, raw material preparation; step 2, premixing treatment; step 3, plasticizing and extruding; step 4, cooling and shaping; step 5, cutting and testing; step 6, surface pretreatment; step 7, primer coating; step 8, topcoat coating;

[0051] In the above step 1, 90 parts of CPVC resin, 1 part of stabilizer, 4 parts of plasticizer, 3 parts of lubricant, 3 parts of impact modifier, 8 parts of filler, 3 parts of masterbatch and 15 parts of nano-silicon dioxide are weighed according to the weight of each group and set aside;

[0052] In the above step 2, the CPVC resin, stabilizer, plasticizer, lubricant, impact modifier, filler, masterbatch and nano-silica prepared in the above step 1 are respectively placed in a high-speed mixer, and high-speed mixing is performed in the high-speed mixer to obtain a mixed raw material for standby use; during the high-speed mixing in the high-speed mixer, the stirring speed in the mixer is 450r / min, and the high-speed mixing time is 10min, and the temperature in the high-speed mixer during the mixing process is 100°C;

[0053] In the above step 3, the mixed raw material prepared in the above step 2 is put into a twin-screw extruder for plasticizing and extruding, and after plasticizing and extruding, it is filled into a tube-shaped mold for molding to obtain a tube blank for standby use; the screw diameter of the twin-screw extruder used for plasticizing and extruding is 45 mm, and the screw aspect ratio L / D specification is 32; the screw speed during the extrusion process is 200 r / min, the temperature of the hopper section of the twin-screw extruder is 135° C., the temperature of the homogenizing section is 160° C., the temperature of the metering section is 200° C., and the temperature of the extruder head is 190° C., and the extrusion pressure is 20 MPa;

[0054] In the above step 4, after demoulding, the pipe blank prepared in the above step 3 is subjected to multi-stage cooling to obtain the original pipe after cooling for standby use; the initial cooling stage of the multi-stage cooling uses a cold water tank, and the water temperature in the cold water tank is 15°C, the intermediate cooling stage uses cold water for spraying treatment, and the cold water temperature used in the spraying treatment process is 20°C, and the final cooling stage is air cooling to reduce the temperature to 38°C;

[0055] In the above step 5, the original pipe obtained in the above step 4 is cut, and an appearance inspection is performed after the cutting process. After the inspection, a standard pipe is obtained and set aside; the cutting line speed during the cutting process is 1m / min; and the appearance inspection after the cutting includes the inspection of bubbles, cracks and color difference on the surface of the pipe, and the outer diameter, wall thickness and other dimensions of the pipe;

[0056] In the above step 6, the standard pipe obtained in the above step 5 is cleaned with a solvent, then rinsed with clean water, polished with sandpaper after rinsing, and then cleaned and dried to obtain a clean pipe for standby use; the solvent used in the process of cleaning the pipe with a solvent is acetone, and the time for rinsing with clean water is 3 minutes, the temperature during drying is 60°C, and the drying time is 40 minutes;

[0057] In the above step 7, a spray gun is used to evenly spray the primer on the clean pipe obtained in the above step 6, and the primer is placed in a constant temperature chamber for drying after spraying; the spray primer is an epoxy primer, and the spray thickness of the primer is 30 μm. The temperature during the drying process in the constant temperature chamber is 38° C., and the drying time is 150 minutes;

[0058] In the above step eight, a layer of topcoat is sprayed on the primer in the above step seven to obtain a high-strength corrosion-resistant CPVC pipe; the topcoat selected is fluorocarbon topcoat, and before spraying, the fluorocarbon topcoat is placed in a mixer and a diluent is added at a stirring speed of 45r / min to adjust the spraying viscosity, and then the topcoat is applied with a spray gun to a coating thickness of 30μm. After spraying, it is left to stand at room temperature for 1500min.

[0059] The high-strength, corrosion-resistant CPVC pipes obtained in the above examples were tested for performance and compared with common CPVC pipes on the market. The results are shown in the following table:

[0060] <![CDATA[Density (g / cm 3 )]]> Tensile strength(MPa) <![CDATA[Impact strength (kJ / m 2 )]]> Example 1 1.78 80 18.56 Example 2 1.77 82 17.89 Example 3 1.78 79 18.25 Comparative Example 1.56 45 10.05

[0061] Based on the above, the advantages of the present invention are that, when used, the present invention uses nano silicon dioxide formed by hydrolysis and condensation reaction with tetraethyl orthosilicate as a precursor and is added as an auxiliary material to the traditional CPVC pipe formula, and after the blending is completed, it can maintain a good combination with the matrix resin to generate a strong interface layer, thereby enhancing the strength of the prepared pipe; before coating, acetone is used as a solvent to clean the surface of the pipe, and then it is cleaned and dried to remove the oil and impurities remaining on the surface of the pipe, so as to avoid affecting the subsequent spraying process and ensure the production qualification rate of the pipe; in the process of surface treatment, epoxy primer and fluorocarbon topcoat are applied in sequence to form a double-layer coating protection structure, and at the same time, the primer increases the bonding strength of the fluorocarbon topcoat, prevents the topcoat from falling off, provides an additional protective layer for the pipe, slows down the aging speed of the pipe, further improves the corrosion resistance and prolongs the service life of the pipe.

[0062] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A high-strength, corrosion-resistant CPVC pipe formula, comprising: CPVC resin, stabilizer, plasticizer, lubricant, impact modifier, filler, masterbatch and nano silicon dioxide; characterized in that the weight proportions of the components are: 80-90 parts of CPVC resin, 1-3 parts of stabilizer, 2-4 parts of plasticizer, 3-5 parts of lubricant, 1-3 parts of impact modifier, 8-12 parts of filler, 2-3 parts of masterbatch and 15-20 parts of nano silicon dioxide.

2. A high-strength, corrosion-resistant CPVC pipe formula, characterized by: The nano silicon dioxide is prepared by hydrolysis and condensation reaction with tetraethyl orthosilicate as a precursor; and the preparation process of the nano silicon dioxide is as follows: firstly, tetraethyl orthosilicate is dissolved in anhydrous ethanol, then stirred at a stirring speed of 45 to 60 r / min, and deionized water and a hydrochloric acid solution with a concentration of 10% are added dropwise to the solution during the stirring process to initiate the hydrolysis reaction of tetraethyl orthosilicate, and after 10 to 15 minutes, the solution is stirred at a stirring speed of 35 to 40 r / min to promote condensation of the hydrolysis product to form a stable sol, and then the sol is placed at a temperature of 35 to 38° C. to age and gel, and finally the aged sol is placed at -5 to -3° C. for freeze drying for 30 to 45 minutes, and after freeze drying, the solution is calcined at a temperature of 300 to 350° C. to remove residual organic matter and water, so as to obtain the nano silicon dioxide.

3. A method for preparing a high-strength, corrosion-resistant CPVC pipe, comprising the following steps: Step 1, raw material preparation; Step 2, premixing; Step 3, plasticizing and extruding; Step 4, cooling and shaping; Step 5, cutting and testing; Step 6, surface pretreatment; Step 7, primer coating; Step 8, topcoat coating; It is characterized by: In the above step 1, 80-90 parts of CPVC resin, 1-3 parts of stabilizer, 2-4 parts of plasticizer, 3-5 parts of lubricant, 1-3 parts of impact modifier, 8-12 parts of filler, 2-3 parts of masterbatch and 15-20 parts of nano-silicon dioxide are weighed according to the weight of each group and set aside; In the above step 2, the CPVC resin, stabilizer, plasticizer, lubricant, impact modifier, filler, masterbatch and nano-silicon dioxide prepared in the above step 1 are respectively placed in a high-speed mixer, and mixed at high speed in the high-speed mixer to obtain a mixed raw material for standby use; In the above step 3, the mixed raw material prepared in the above step 2 is put into a twin-screw extruder for plasticization and extrusion, and after plasticization and extrusion, it is filled into a tube-shaped mold for molding to obtain a tube blank for standby use; In the above step 4, after demoulding, the tube blank prepared in the above step 3 is cooled in multiple stages to obtain the original tube for standby use; In the above step 5, the original pipe obtained in the above step 4 is cut, and an appearance inspection is performed after the cutting process. After the inspection, a standard pipe is obtained for standby use; In the above step 6, the standard pipe obtained in the above step 5 is cleaned with a solvent, then rinsed with clean water, polished with sandpaper after rinsing, and then cleaned and dried to obtain a clean pipe for standby use; In the above step 7, a spray gun is used to evenly spray the primer on the clean pipe obtained in the above step 6, and the primer is placed in a constant temperature chamber for drying after spraying; In the above step eight, a layer of topcoat is sprayed on the primer in the above step seven to obtain a high-strength, corrosion-resistant CPVC pipe.

4. The method for preparing a high-strength, corrosion-resistant CPVC pipe according to claim 3, characterized in that: In the step 2, during the high-speed mixing in the high-speed mixer, the stirring speed in the mixer is 300-450 r / min, the high-speed mixing time is 10-20 min, and the temperature in the high-speed mixer during the mixing process is 80-100° C.

5. The method for preparing a high-strength, corrosion-resistant CPVC pipe according to claim 3, characterized in that: In the step three, the screw diameter of the twin-screw extruder used for plasticizing extrusion is 45-90 mm, and the screw aspect ratio L / D specification is 24-32; the screw speed during the extrusion process is 200-300 r / min, the temperature of the hopper section of the twin-screw extruder is 130-135°C, the temperature of the homogenizing section is 160-180°C, the temperature of the metering section is 180-200°C, and the temperature of the extruder head is 190-210°C, and the extrusion pressure is 10-20 MPa.

6. The method for preparing a high-strength, corrosion-resistant CPVC pipe according to claim 3, characterized in that: In the step 4, the initial cooling stage of the multi-stage cooling uses a cold water tank, and the water temperature in the cold water tank is 10-15°C, the intermediate cooling stage uses cold water for spraying treatment, and the temperature of the cold water used in the spraying process is 20-25°C, and the final cooling stage uses air cooling to reduce the temperature to 25-38°C.

7. The method for preparing a high-strength, corrosion-resistant CPVC pipe according to claim 3, characterized in that: In the step 5, the cutting line speed during the cutting process is 1 to 2.4 m / min; and the appearance inspection after the cutting is completed includes the inspection of bubbles, cracks and color difference on the surface of the pipe, as well as the outer diameter, wall thickness and other dimensional inspections of the pipe.

8. The method for preparing a high-strength, corrosion-resistant CPVC pipe according to claim 3, characterized in that: In step six, the solvent used in the process of using solvent to clean the pipe is acetone, and the time for rinsing with clean water is 2 to 3 minutes. The temperature during drying is 60 to 63° C., and the drying time is 20 to 40 minutes.

9. The method for preparing a high-strength, corrosion-resistant CPVC pipe according to claim 3, characterized in that: In the step seven, the spray primer is epoxy primer, and the spray thickness of the primer is 20-30 μm. The temperature during the drying process in the constant temperature chamber is 38-45° C., and the drying process time is 120-150 min.

10. The method for preparing a high-strength, corrosion-resistant CPVC pipe according to claim 3, characterized in that: In the step eight, the topcoat selected is fluorocarbon topcoat. Before spraying, the fluorocarbon topcoat is placed in a mixer and a diluent is added at a stirring speed of 30 to 45 r / min to adjust the spraying viscosity. The topcoat is then applied with a spray gun to a coating thickness of 30 to 50 μm. After spraying, the topcoat is allowed to stand at room temperature for 1440 to 1500 min.

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