A high-toughness biaxially oriented chlorinated polyvinyl chloride pipe and its preparation method

Abstract

The invention discloses a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe and a preparation method thereof. The invention deposits nano silicon dioxide on the surface of glass fiber by a hydrothermal reaction, thereby ensuring uniform distribution of the nano silicon dioxide and effectively filling microscopic pores on the surface of the glass fiber to form a more uniform composite structure, thereby significantly enhancing the overall mechanical properties of the chlorinated polyvinyl chloride pipe. Subsequently, trifluoromethylstyrene and 4-vinylbenzoic acid are grafted on the surface of the glass fiber composite material by a double bond addition reaction, and the introduction of fluorine groups significantly improves the stability of the pipe in a high temperature environment. The rigid structure of the benzene ring is helpful to improve the durability of the pipe under light conditions and avoid degradation reactions caused by ultraviolet irradiation. Epoxy resin is then used to perform surface treatment on the modified glass fiber composite material, which is beneficial to increasing the dispersibility and adhesion of the modified toughening agent, thereby increasing the mechanical properties of the chlorinated polyvinyl chloride pipe.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe and a preparation method thereof. Background Art

[0002] Chlorinated polyvinyl chloride (CPVC) is a thermoplastic resin obtained by chlorination of polyvinyl chloride (PVC), which has more excellent chemical and physical properties. Usually, the chlorine content of CPVC is between 65% and 71%, which significantly improves its mechanical properties, especially in terms of heat resistance, solvent resistance and flame retardancy. Compared with traditional PVC, the heat resistance of CPVC has been significantly improved, making it more widely used in high temperature environments, especially suitable for water pipes in high-rise buildings, hot water pipes in central air conditioners, and cable sheaths.

[0003] Compared with PVC resin, the molecular structure of CPVC changes due to the increase of chlorine content, and the proportion of its defective structure increases accordingly. The existence of these defective structures may cause the thermal stability of CPVC to decrease, especially when the chlorine content exceeds 68%, the thermal stability will drop sharply, which means that in high temperature environment, CPVC material may decompose or deteriorate, limiting its application range under extreme conditions.

[0004] Chinese patent document CN202110760862.4 discloses a chlorinated polyvinyl chloride composition with excellent stability, and a preparation method and application thereof. The chlorinated polyvinyl chloride composition is prepared with CPVC resin, a main stabilizer, an auxiliary stabilizer, a lubricant, an impact modifier, an antioxidant, a colorant and a pigment as raw materials. On the basis of using the main stabilizer, a first alkaline metal salt with a layered structure, a second metal salt and a hydroxylamine compound with a strong oxidizing effect are further added as auxiliary stabilizers. The synergistic effect between the three is utilized to make the chlorinated polyvinyl chloride composition have a longer stability time and better stability. The prepared chlorinated polyvinyl chloride pipe has good heat resistance and thermal stability. However, the amount of processing aids added in the above patent is too much, and it is difficult to ensure the processing stability of the material. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe and a preparation method thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] A high-toughness biaxially oriented chlorinated polyvinyl chloride pipe comprises the following raw materials, measured by weight: 60-80 parts of chlorinated polyvinyl chloride resin, 20-30 parts of polyvinyl chloride resin, 5-10 parts of modified toughening agent, 10-15 parts of dimethyl phthalate, 3-5 parts of zinc stearate, 1-2 parts of PE wax, 2-3 parts of stearic acid and 0.2-0.4 parts of color powder.

[0008] Specifically, in some embodiments of the present invention, the chlorinated polyvinyl chloride resin can be selected from 60 parts, 62 parts, 65 parts, 68 parts, 70 parts, 72 parts, 74 parts, 76 parts, 78 parts, and 80 parts; but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0009] Specifically, in some embodiments of the present invention, the polyvinyl chloride resin can be selected to be 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, and 30 parts; but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0010] In the present invention, the addition of polyvinyl chloride resin (PVC) can improve the processing fluidity of chlorinated polyvinyl chloride resin (CPVC), making the mixture easier to process and shape. Since the melt ductility of CPVC is relatively poor, the addition of PVC can reduce the melt crushing phenomenon that may occur during the processing, thereby improving the surface quality and processing efficiency of the product.

[0011] Specifically, in some embodiments of the present invention, the modified toughening agent can be selected to be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts; but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0012] More specifically, the preparation method of the modified toughening agent is as follows:

[0013] S1, ultrasonically dispersing glass fibers in an ethanol aqueous solution, then adding tetraethyl orthosilicate, ammonia water and Tween 80 thereto, performing a hydrothermal reaction, and after the reaction is completed, filtering, washing and drying to obtain a glass fiber composite material;

[0014] S2, dispersing the glass fiber composite material in an ethanol aqueous solution, then adding vinyltrimethoxysilane thereto, stirring for 2-5 hours, filtering, washing, and drying to obtain a double-bond modified glass fiber composite material;

[0015] S3, dispersing the double-bond modified glass fiber composite material in an organic solvent, then adding p-trifluoromethylstyrene, 4-vinylbenzoic acid and an initiator thereto, heating and stirring to react, and after the reaction is completed, filtering, washing and drying to obtain a modified glass fiber composite material;

[0016] S4. Add epoxy resin to acetone solvent, stir evenly, then add modified glass fiber composite material and stannous octoate, heat to react, and after the reaction is completed, dry to remove acetone, crush and sieve to obtain a modified toughening agent.

[0017] Wherein, in step S1, the mass ratio of glass fiber, tetraethyl orthosilicate, ammonia water and Tween 80 is 5-10:4-8:20-30:0.5-1.

[0018] Specifically, the mass fraction of aqueous ammonia is 25-30%. In some embodiments of the present invention, for example, 25%, 26%, 28%, 29%, and 30% can be selected; but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] In step S1, the temperature of the hydrothermal reaction is 120-150°C, for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C can be selected; the time of the hydrothermal reaction is 8-16h, for example, 8h, 10h, 12h, 14h, 15h, 16h can be selected; but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] Specifically, in step S2, the mass ratio of the glass fiber composite material to vinyltrimethoxysilane is 8-12:1-3, for example, 8:1, 8:2, 8:3, 10:1, 10:2, 10:3, 12:1, 12:2, 12:3 can be selected, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Specifically, in step S3, the mass ratio of the double-bond modified glass fiber composite material, p-trifluoromethylstyrene, 4-vinylbenzoic acid and initiator is 10-15:3-6:2-5:0.5-1.

[0022] Wherein, the initiator is selected from benzoyl peroxide or di-tert-butyl peroxide.

[0023] Specifically, in step S3, the temperature of the heating and stirring reaction is 50-60°C, for example, 50°C, 52°C, 54°C, 55°C, 56°C, 58°C, 59°C, and 60°C can be selected; the time of the heating and stirring reaction is 3-5h, for example, 3h, 3.5h, 4h, 4.5h, and 5h can be selected; but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] Specifically, in step S4, the mass ratio of epoxy resin, modified glass fiber composite material and stannous octoate is 4-8:10-15:0.5-1.

[0025] Specifically, in step S4, the temperature of the heating reaction is 40-50°C, for example, 40°C, 42°C, 44°C, 45°C, 46°C, 48°C, and 50°C can be selected; the time of the heating reaction is 2-4h, for example, 2h, 2.5h, 3h, 3.5h, and 4h can be selected; but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] Specifically, the amount of dimethyl phthalate can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, or 15 parts, but the amount is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0027] In the present invention, dimethyl phthalate (DBP) can increase the flexibility of CPVC resin, making it easier to bend and shape during processing and use, and improving its brittleness. At the same time, the addition of DBP can also improve the performance of CPVC in a low temperature environment, so that it can still maintain good flexibility and performance under cold conditions.

[0028] Specifically, the zinc stearate can be selected to be 3 parts, 3.5 parts, 4 parts, 4.5 parts, or 5 parts, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Specifically, the PE wax can be selected as 1 part, 1.2 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.8 parts, 1.9 parts, and 2 parts; but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] Specifically, stearic acid can be selected from 2 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts, 2.6 parts, 2.7 parts, 2.8 parts, 2.9 parts, and 3 parts; but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] In the present invention, zinc stearate, PE wax and stearic acid are used as lubricants to reduce the friction of CPVC during processing, thereby reducing melt viscosity, improving its fluidity, and making processing smoother.

[0032] Specifically, the color powder can be selected in 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, and 0.4 parts, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] Wherein, the color powder is selected from titanium dioxide, carbon black, phthalocyanine blue, phthalocyanine green or cadmium red.

[0034] The present invention also provides a method for preparing the above-mentioned high-toughness biaxially oriented chlorinated polyvinyl chloride pipe, comprising the following steps: uniformly mixing the raw materials according to weight, then extruding the blended raw materials through a twin-screw extruder to obtain a prefabricated pipe, then biaxially orienting the prefabricated pipe, and rapidly cooling and shaping after the orientation is completed to obtain the high-toughness biaxially oriented chlorinated polyvinyl chloride pipe.

[0035] The orientation temperature of the biaxial orientation is 85-110°C for the inner and outer walls, the air pressure at the expansion body is 0.2-0.6Mpa, and the orientation ratio is 1.15-1.25 times in the axial direction and 1.75-1.85 times in the circumferential direction.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The high-toughness biaxially oriented chlorinated polyvinyl chloride pipe provided by the present invention uses chlorinated polyvinyl chloride resin (CPVC) as the main raw material. After toughening modification, the disadvantage of poor compressive deformation resistance of CPVC pipe is greatly improved. The prepared chlorinated polyvinyl chloride pipe has the advantages of high Vicat softening temperature, high strength, high toughness, excellent weather resistance, etc. It is mainly used in the protection pipe of high and low voltage power cables, plays the role of cable guiding and protection, and improves the stability and safety of the power system.

[0038] (2) The present invention deposits nano-silica on the surface of glass fiber by means of a hydrothermal reaction, thereby ensuring uniform distribution of nano-silica and effectively filling the microscopic pores on the surface of glass fiber to form a more uniform composite structure, thereby significantly enhancing the overall mechanical properties of the chlorinated polyvinyl chloride pipe. In addition, the high specific surface area of ​​nano-silica provides more reaction contact sites, which is conducive to the efficient conduct of subsequent chemical reactions.

[0039] (3) The present invention grafts trifluoromethylstyrene and 4-vinylbenzoic acid onto the surface of the glass fiber composite material through a double bond addition reaction. Trifluoromethylstyrene and 4-vinylbenzoic acid contain a large number of fluorine-containing groups and rigid benzene ring structures. The introduction of fluorine groups significantly improves the stability of the pipe in a high temperature environment and reduces the material degradation caused by thermal aging. The rigid structure of the benzene ring helps to improve the durability of the pipe under light conditions and avoid degradation reactions caused by ultraviolet rays, thereby extending the service life of the pipe.

[0040] (4) The present invention uses epoxy resin to perform surface treatment on the modified glass fiber composite material. The epoxy groups in the epoxy resin are ring-opened under the catalytic action of stannous octoate and chemically react with the carboxyl groups in the modified glass fiber composite material. The epoxy resin is grafted onto the surface of the modified glass fiber composite material through chemical action, which is beneficial to increase the dispersibility and adhesion of the modified toughening agent, thereby increasing the mechanical properties of the chlorinated polyvinyl chloride pipe. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0042] It should be noted that, unless otherwise specified, the chemical reagents involved in the present invention were purchased through commercial channels.

[0043] The chlorinated polyvinyl chloride resin used in the present invention has the brand name LC88029, purchased from Suzhou Fuliying Plastic Chemical Co., Ltd.

[0044] Polyvinyl chloride resin CAS number: 9002-86-2, purchased from Zibo Anhao Chemical Co., Ltd.;

[0045] Glass fiber grade: GF60-01, purchased from Dongguan Tianzhihong Plastic Chemical Co., Ltd.;

[0046] The model of epoxy resin is epoxy resin E44, purchased from Wanqing Chemical Technology Co., Ltd.;

[0047] Dimethyl phthalate, CAS number: 131-11-3, purchased from Jinan Zhengkang Chemical Co., Ltd.;

[0048] Zinc stearate CAS number: 557-05-1, purchased from Shandong Shouhua Chemical Co., Ltd.;

[0049] PE wax and stearic acid were purchased from Wuhan Xindongyi Chemical Co., Ltd.;

[0050] Cadmium red powder was purchased from Dongguan Jinsuyan Plastic Technology Co., Ltd.

[0051] Example 1

[0052] A method for preparing a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe comprises the following steps:

[0053] 65 parts of chlorinated polyvinyl chloride resin, 25 parts of polyvinyl chloride resin, 8 parts of modified toughening agent, 12 parts of dimethyl phthalate, 4 parts of zinc stearate, 1 part of PE wax, 2 parts of stearic acid and 0.3 parts of cadmium red powder are mixed uniformly at 110°C in a high-speed mixer and kept in the temperature range for 10 minutes to obtain a mixed material; then the mixed material is cooled to room temperature and extruded by a twin-screw extruder, the screw compression ratio is 3, the speed ratio of the reducer is 25; the temperature of each section of the extruder body is: 150°C for the first section, 160°C for the second section, and 160°C for the third section; the confluence core temperature is 145 ℃; the internal heating temperature is 170℃; the temperature of each section of the mold is: 145℃ for the first section, 160℃ for the second section, and 165℃ for the third section; the melt pressure is 10Mpa, the melt temperature is 170℃, the feeding torque is 6%, the traction ratio is 1.15, and a prefabricated tube is obtained after extrusion; the prefabricated tube is then biaxially oriented, the orientation temperature is 90℃ for the inner and outer walls, and the air pressure at the expansion body is 0.3Mpa; the orientation ratio is 1.15 times in the axial direction and 1.75 times in the circumferential direction. After the orientation is completed, it is quickly cooled and shaped to obtain a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe.

[0054] Wherein, the preparation method of the modified toughening agent is as follows:

[0055] S1, ultrasonically dispersing 5 g of glass fiber in 100 mL of 80 wt% ethanol aqueous solution, then adding 4 g of tetraethyl orthosilicate, 20 g of 25 wt% ammonia water and 0.8 g of Tween 80 thereto, hydrothermally reacting at 120° C. for 16 h, and after the reaction is completed, filtering, washing and drying to obtain a glass fiber composite material;

[0056] S2, dispersing 8 g of the glass fiber composite material in 100 mL of 80 wt% ethanol aqueous solution, then adding 1 g of vinyltrimethoxysilane thereto, stirring for 3 h, filtering, washing, and drying to obtain a double-bond modified glass fiber composite material;

[0057] S3, dispersing 10g of the double-bond modified glass fiber composite material in 150mL of the organic solvent DMF, then adding 3g of p-trifluoromethylstyrene, 2g of 4-vinylbenzoic acid and 0.8g of benzoyl peroxide thereto, heating and stirring at 50°C for 5h, and after the reaction is completed, filtering, washing and drying to obtain a modified glass fiber composite material;

[0058] S4. Add 4 g of epoxy resin into 100 mL of acetone solvent, stir evenly, then add 10 g of modified glass fiber composite material and 0.6 g of stannous octoate, heat and react at 40°C for 4 hours. After the reaction is completed, dry to remove acetone, crush through a 400-mesh sieve to obtain a modified toughening agent.

[0059] Example 2

[0060] A method for preparing a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe comprises the following steps:

[0061] 60 parts of chlorinated polyvinyl chloride resin, 20 parts of polyvinyl chloride resin, 5 parts of modified toughening agent, 10 parts of dimethyl phthalate, 3 parts of zinc stearate, 1 part of PE wax, 2 parts of stearic acid and 0.2 parts of cadmium red powder are mixed uniformly at 110°C in a high-speed mixer and kept in the temperature range for 10 minutes to obtain a mixed material; then the mixed material is cooled to room temperature and extruded by a twin-screw extruder, the screw compression ratio is 3, the speed ratio of the reducer is 25; the temperature of each section of the extruder body is: 150°C for the first section, 160°C for the second section, and 160°C for the third section; the confluence core temperature is 145 ℃; the internal heating temperature is 170℃; the temperature of each section of the mold is: 145℃ for the first section, 160℃ for the second section, and 165℃ for the third section; the melt pressure is 10Mpa, the melt temperature is 170℃, the feeding torque is 6%, the traction ratio is 1.15, and a prefabricated tube is obtained after extrusion; the prefabricated tube is then biaxially oriented, the orientation temperature is 90℃ for the inner and outer walls, and the air pressure at the expansion body is 0.3Mpa; the orientation ratio is 1.15 times in the axial direction and 1.75 times in the circumferential direction. After the orientation is completed, it is quickly cooled and shaped to obtain a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe.

[0062] Wherein, the preparation method of the modified toughening agent is as follows:

[0063] S1, ultrasonically dispersing 10 g of glass fiber in 100 mL of 80 wt% ethanol aqueous solution, then adding 8 g of tetraethyl orthosilicate, 30 g of 25 wt% ammonia water and 1 g of Tween 80 thereto, hydrothermally reacting at 150° C. for 8 h, and after the reaction is completed, filtering, washing and drying to obtain a glass fiber composite material;

[0064] S2, dispersing 12 g of the glass fiber composite material in 100 mL of 80 wt% ethanol aqueous solution, then adding 3 g of vinyltrimethoxysilane thereto, stirring for 3 h, filtering, washing, and drying to obtain a double-bond modified glass fiber composite material;

[0065] S3, dispersing 15g of the double-bond modified glass fiber composite material in 150mL of the organic solvent DMF, then adding 3g of p-trifluoromethylstyrene, 5g of 4-vinylbenzoic acid and 1g of benzoyl peroxide thereto, heating and stirring at 60°C for 3h, and after the reaction is completed, filtering, washing and drying to obtain a modified glass fiber composite material;

[0066] S4. Add 8 g of epoxy resin into 100 mL of acetone solvent, stir evenly, then add 15 g of modified glass fiber composite material and 1 g of stannous octoate, heat and react at 50°C for 2 h. After the reaction is completed, dry to remove acetone, crush through a 400-mesh sieve to obtain a modified toughening agent.

[0067] Example 3

[0068] A method for preparing a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe comprises the following steps:

[0069] 80 parts of chlorinated polyvinyl chloride resin, 30 parts of polyvinyl chloride resin, 10 parts of modified toughening agent, 15 parts of dimethyl phthalate, 5 parts of zinc stearate, 2 parts of PE wax, 3 parts of stearic acid and 0.4 parts of cadmium red powder are mixed uniformly at 110°C in a high-speed mixer and kept in the temperature range for 10 minutes to obtain a mixed material; then the mixed material is cooled to room temperature and extruded through a twin-screw extruder, the screw compression ratio is 3, the speed ratio of the reducer is 25; the temperature of each section of the extruder body is: 150°C for the first section, 160°C for the second section, and 160°C for the third section; the confluence core temperature is 145 ℃; the internal heating temperature is 170℃; the temperature of each section of the mold is: 145℃ for the first section, 160℃ for the second section, and 165℃ for the third section; the melt pressure is 10Mpa, the melt temperature is 170℃, the feeding torque is 6%, the traction ratio is 1.15, and a prefabricated tube is obtained after extrusion; the prefabricated tube is then biaxially oriented, the orientation temperature is 90℃ for the inner and outer walls, and the air pressure at the expansion body is 0.3Mpa; the orientation ratio is 1.15 times in the axial direction and 1.75 times in the circumferential direction. After the orientation is completed, it is quickly cooled and shaped to obtain a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe.

[0070] Wherein, the preparation method of the modified toughening agent is as follows:

[0071] S1, ultrasonically dispersing 8 g of glass fiber in 100 mL of 80 wt% ethanol aqueous solution, then adding 6 g of tetraethyl orthosilicate, 25 g of 25 wt% ammonia water and 0.6 g of Tween 80 thereto, hydrothermally reacting at 130° C. for 12 h, and after the reaction is completed, filtering, washing and drying to obtain a glass fiber composite material;

[0072] S2, dispersing 10 g of the glass fiber composite material in 100 mL of 80 wt% ethanol aqueous solution, then adding 2 g of vinyltrimethoxysilane thereto, stirring for 3 h, filtering, washing, and drying to obtain a double-bond modified glass fiber composite material;

[0073] S3, dispersing 12g of the double-bond modified glass fiber composite material in 150mL of the organic solvent DMF, then adding 6g of p-trifluoromethylstyrene, 3g of 4-vinylbenzoic acid and 0.8g of benzoyl peroxide thereto, heating and stirring at 55°C for 4h, and after the reaction is completed, filtering, washing and drying to obtain a modified glass fiber composite material;

[0074] S4. Add 6 g of epoxy resin into 100 mL of acetone solvent, stir evenly, then add 12 g of modified glass fiber composite material and 0.6 g of stannous octoate, heat and react at 45°C for 3 h. After the reaction is completed, dry to remove acetone, crush through a 400-mesh sieve to obtain a modified toughening agent.

[0075] Comparative Example 1

[0076] A method for preparing a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe comprises the following steps:

[0077] 65 parts of chlorinated polyvinyl chloride resin, 25 parts of polyvinyl chloride resin, 8 parts of modified toughening agent, 12 parts of dimethyl phthalate, 4 parts of zinc stearate, 1 part of PE wax, 2 parts of stearic acid and 0.3 parts of cadmium red powder are mixed uniformly at 110°C in a high-speed mixer and kept in the temperature range for 10 minutes to obtain a mixed material; then the mixed material is cooled to room temperature and extruded by a twin-screw extruder, the screw compression ratio is 3, the speed ratio of the reducer is 25; the temperature of each section of the extruder body is: 150°C for the first section, 160°C for the second section, and 160°C for the third section; the confluence core temperature is 145 ℃; the internal heating temperature is 170℃; the temperature of each section of the mold is: 145℃ for the first section, 160℃ for the second section, and 165℃ for the third section; the melt pressure is 10Mpa, the melt temperature is 170℃, the feeding torque is 6%, the traction ratio is 1.15, and a prefabricated tube is obtained after extrusion; the prefabricated tube is then biaxially oriented, the orientation temperature is 90℃ for the inner and outer walls, and the air pressure at the expansion body is 0.3Mpa; the orientation ratio is 1.15 times in the axial direction and 1.75 times in the circumferential direction. After the orientation is completed, it is quickly cooled and shaped to obtain a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe.

[0078] Wherein, the preparation method of the modified toughening agent is as follows:

[0079] S1, dispersing 8 g of glass fiber in 100 mL of 80 wt% ethanol aqueous solution, then adding 1 g of vinyltrimethoxysilane thereto, stirring for 3 h, filtering, washing, and drying to obtain a double-bond modified glass fiber material;

[0080] S2, dispersing 10g of double-bond modified glass fiber material in 150mL of organic solvent DMF, then adding 3g of p-trifluoromethylstyrene, 2g of 4-vinylbenzoic acid and 0.8g of benzoyl peroxide thereto, heating and stirring at 50°C for 5h, after the reaction is completed, filtering, washing and drying to obtain a modified glass fiber material;

[0081] S3. Add 4 g of epoxy resin into 100 mL of acetone solvent, stir evenly, then add 10 g of modified glass fiber material and 0.6 g of stannous octoate, heat and react at 40°C for 4 h. After the reaction is completed, dry and remove acetone, and crush through a 400-mesh sieve to obtain a modified toughening agent.

[0082] Compared with Example 1, in Comparative Example 1, the glass fiber was not treated with loading nano-silica.

[0083] Comparative Example 2

[0084] A method for preparing a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe comprises the following steps:

[0085] 65 parts of chlorinated polyvinyl chloride resin, 25 parts of polyvinyl chloride resin, 8 parts of modified toughening agent, 12 parts of dimethyl phthalate, 4 parts of zinc stearate, 1 part of PE wax, 2 parts of stearic acid and 0.3 parts of cadmium red powder are mixed uniformly at 110°C in a high-speed mixer and kept in the temperature range for 10 minutes to obtain a mixed material; then the mixed material is cooled to room temperature and extruded by a twin-screw extruder, the screw compression ratio is 3, the speed ratio of the reducer is 25; the temperature of each section of the extruder body is: 150°C for the first section, 160°C for the second section, and 160°C for the third section; the confluence core temperature is 145 ℃; the internal heating temperature is 170℃; the temperature of each section of the mold is: 145℃ for the first section, 160℃ for the second section, and 165℃ for the third section; the melt pressure is 10Mpa, the melt temperature is 170℃, the feeding torque is 6%, the traction ratio is 1.15, and a prefabricated tube is obtained after extrusion; the prefabricated tube is then biaxially oriented, the orientation temperature is 90℃ for the inner and outer walls, and the air pressure at the expansion body is 0.3Mpa; the orientation ratio is 1.15 times in the axial direction and 1.75 times in the circumferential direction. After the orientation is completed, it is quickly cooled and shaped to obtain a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe.

[0086] Wherein, the preparation method of the modified toughening agent is as follows:

[0087] S1, ultrasonically dispersing 5 g of glass fiber in 100 mL of 80 wt% ethanol aqueous solution, then adding 4 g of tetraethyl orthosilicate, 20 g of 25 wt% ammonia water and 0.8 g of Tween 80 thereto, hydrothermally reacting at 120° C. for 16 h, and after the reaction is completed, filtering, washing and drying to obtain a glass fiber composite material;

[0088] S2. Add 4 g of epoxy resin into 100 mL of acetone solvent, stir evenly, then add 10 g of glass fiber composite material and 0.6 g of stannous octoate, heat and react at 40°C for 4 h. After the reaction is completed, dry to remove acetone, crush through a 400-mesh sieve to obtain a modified toughening agent.

[0089] Compared with Example 1, in Comparative Example 2, p-trifluoromethylstyrene and 4-vinylbenzoic acid were not used to modify the glass fiber composite material.

[0090] Comparative Example 3

[0091] A method for preparing a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe comprises the following steps:

[0092] 65 parts of chlorinated polyvinyl chloride resin, 25 parts of polyvinyl chloride resin, 8 parts of modified toughening agent, 12 parts of dimethyl phthalate, 4 parts of zinc stearate, 1 part of PE wax, 2 parts of stearic acid and 0.3 parts of cadmium red powder are mixed uniformly at 110°C in a high-speed mixer and kept in the temperature range for 10 minutes to obtain a mixed material; then the mixed material is cooled to room temperature and extruded by a twin-screw extruder, the screw compression ratio is 3, the speed ratio of the reducer is 25; the temperature of each section of the extruder body is: 150°C for the first section, 160°C for the second section, and 160°C for the third section; the confluence core temperature is 145 ℃; the internal heating temperature is 170℃; the temperature of each section of the mold is: 145℃ for the first section, 160℃ for the second section, and 165℃ for the third section; the melt pressure is 10Mpa, the melt temperature is 170℃, the feeding torque is 6%, the traction ratio is 1.15, and a prefabricated tube is obtained after extrusion; the prefabricated tube is then biaxially oriented, the orientation temperature is 90℃ for the inner and outer walls, and the air pressure at the expansion body is 0.3Mpa; the orientation ratio is 1.15 times in the axial direction and 1.75 times in the circumferential direction. After the orientation is completed, it is quickly cooled and shaped to obtain a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe.

[0093] Wherein, the preparation method of the modified toughening agent is as follows:

[0094] S1, ultrasonically dispersing 5 g of glass fiber in 100 mL of 80 wt% ethanol aqueous solution, then adding 4 g of tetraethyl orthosilicate, 20 g of 25 wt% ammonia water and 0.8 g of Tween 80 thereto, hydrothermally reacting at 120° C. for 16 h, and after the reaction is completed, filtering, washing and drying to obtain a glass fiber composite material;

[0095] S2, dispersing 8 g of the glass fiber composite material in 100 mL of 80 wt% ethanol aqueous solution, then adding 1 g of vinyltrimethoxysilane thereto, stirring for 3 h, filtering, washing, and drying to obtain a double-bond modified glass fiber composite material;

[0096] S3. Disperse 10 g of double-bond modified glass fiber composite material in 150 mL of organic solvent DMF, then add 3 g of p-trifluoromethylstyrene, 2 g of 4-vinylbenzoic acid and 0.8 g of benzoyl peroxide, heat and stir at 50 °C to react for 5 h. After the reaction is completed, filter, wash, dry, and crush through a 400-mesh sieve to obtain a modified toughening agent.

[0097] Compared with Example 1, in Comparative Example 3, the modified glass fiber composite material was not treated with epoxy resin.

[0098] The relevant properties of the products prepared in Examples 1-3 and Comparative Examples 1-3 were tested, as follows:

[0099] Vicat softening temperature test: Tested in accordance with GB / T 1633-2000 "Determination of Vicat softening temperature (VST) of thermoplastics" standard;

[0100] Tensile strength and elongation at break test: Tested in accordance with GB / T 8804.1-2003 "Determination of tensile properties of thermoplastic pipes Part 1: General principles of test methods";

[0101] Impact test: According to GB / T 1043-2008 standard, the samples were subjected to notched impact strength test at 20°C and 2J pendulum;

[0102] Aging resistance test: Tested in accordance with GB / T 16422.3-2022 "Plastics Laboratory Light Source Exposure Test Method Part 3: Fluorescent Ultraviolet Lamp";

[0103] The test results are shown in Table 1 below:

[0104] Table 1 Test results

[0105]

[0106] Finally, it should be noted that the above embodiments do not limit the present invention in any form. For those skilled in the art, some modifications and improvements can be made to the present invention. Therefore, any modifications or improvements made without departing from the spirit of the present invention are within the scope of the present invention.

Claims

1. A high-toughness biaxially oriented chlorinated polyvinyl chloride pipe, characterized in that: The raw materials include, by weight: 60-80 parts of chlorinated polyvinyl chloride resin, 20-30 parts of polyvinyl chloride resin, 5-10 parts of modified toughening agent, 10-15 parts of dimethyl phthalate, 3-5 parts of zinc stearate, 1-2 parts of PE wax, 2-3 parts of stearic acid, and 0.2-0.4 parts of color powder; Wherein, the preparation method of the modified toughening agent is as follows: S1, ultrasonically dispersing glass fibers in an ethanol aqueous solution, then adding tetraethyl orthosilicate, ammonia water and Tween 80 thereto, performing a hydrothermal reaction, and after the reaction is completed, filtering, washing and drying to obtain a glass fiber composite material; S2, dispersing the glass fiber composite material in an ethanol aqueous solution, then adding vinyltrimethoxysilane thereto, stirring for 2-5 hours, filtering, washing, and drying to obtain a double-bond modified glass fiber composite material; S3, dispersing the double-bond modified glass fiber composite material in an organic solvent, then adding p-trifluoromethylstyrene, 4-vinylbenzoic acid and an initiator thereto, heating and stirring to react, and after the reaction is completed, filtering, washing and drying to obtain a modified glass fiber composite material; S4. Add epoxy resin to acetone solvent, stir evenly, then add modified glass fiber composite material and stannous octoate, heat to react, and after the reaction is completed, dry to remove acetone, crush and sieve to obtain a modified toughening agent.

2. The high-toughness biaxially oriented chlorinated polyvinyl chloride pipe according to claim 1, characterized in that: In step S1, the mass ratio of glass fiber, tetraethyl orthosilicate, ammonia water and Tween 80 is 5-10:4-8:20-30:0.5-1, wherein the mass fraction of ammonia water is 25-30%.

3. The high-toughness biaxially oriented chlorinated polyvinyl chloride pipe according to claim 1, characterized in that: In step S1, the temperature of the hydrothermal reaction is 120-150° C., and the time of the hydrothermal reaction is 8-16 hours.

4. The high-toughness biaxially oriented chlorinated polyvinyl chloride pipe according to claim 1, characterized in that: In step S2, the mass ratio of the glass fiber composite material to vinyltrimethoxysilane is 8-12:1-3.

5. The high-toughness biaxially oriented chlorinated polyvinyl chloride pipe according to claim 1, characterized in that: In step S3, the mass ratio of the double-bond modified glass fiber composite material, p-trifluoromethylstyrene, 4-vinylbenzoic acid and initiator is 10-15:3-6:2-5:0.5-1, and the initiator is selected from benzoyl peroxide or di-tert-butyl peroxide.

6. The high-toughness biaxially oriented chlorinated polyvinyl chloride pipe according to claim 1, characterized in that: In step S3, the temperature of the heating and stirring reaction is 50-60° C., and the time of the heating and stirring reaction is 3-5 h.

7. The high-toughness biaxially oriented chlorinated polyvinyl chloride pipe according to claim 1, characterized in that: In step S4, the mass ratio of epoxy resin, modified glass fiber composite material and stannous octoate is 4-8:10-15:0.5-1.

8. The high-toughness biaxially oriented chlorinated polyvinyl chloride pipe according to claim 1, characterized in that: In step S4, the heating reaction temperature is 40-50° C., and the heating reaction time is 2-4 hours.

9. The method for preparing a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: uniformly mixing the raw materials according to weight, then extruding the blended raw materials through a twin-screw extruder to obtain a prefabricated pipe, then biaxially orienting the prefabricated pipe, and rapidly cooling and shaping the prefabricated pipe after the orientation is completed, so as to obtain a high-toughness biaxially oriented chlorinated polyvinyl chloride pipe.

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