PVC toughening agent, and high-toughness PVC material and preparation method therefor and use thereof

Abstract

The present invention relates to the technical field of PVC materials, Disclosed are a PVC toughening agent, and a high-toughness PVC material and a preparation method therefor and a use thereof. The PVC toughening agent of the present invention is obtained by blending an organosilicon oligomer, surface-activated nano-calcium carbonate, oxidized polyethylene wax, and polyacrylic resin, wherein the mass ratio of the organosilicon oligomer to the surface-activated nano-calcium carbonate to the oxidized polyethylene wax to the polyacrylic resin is 3:2-3:1.5-2.5:3-4. The organosilicon oligomer is an ethoxy-containing organosilicon oligomer obtained by polymerizing methyltriethoxysilane, dimethyldiethoxysilane, and phenyltriethoxysilane. The high-toughness PVC material of the present invention has good impact performance and low-temperature air bending performance, and can be widely applied to low-temperature environments, especially the preparation of the high-toughness PVC electrical sleeve.

Description

A PVC toughening agent, high-toughness PVC material, and preparation method and application thereof Technical Field

[0001] The present invention relates to the technical field of PVC materials, and more particularly to a PVC toughening agent, a high-toughness PVC material, and a preparation method and application thereof. Background Art

[0002] Currently, the physical properties of flame-retardant insulating PVC materials on the market generally meet the technical requirements of the national construction industry standard "JG / T3050-1998." For example, flame-retardant insulating PVC electrical conduit exhibits excellent flame retardancy and insulation properties. Existing electrical conduit standards only require that conduits bend without visible cracks at room temperature without a visible crack, but do not define low-temperature bending. While commercially available conduits generally meet this requirement, actual market demand demands conduits that bend without visible cracks at low temperatures (approximately 0-5°C). This is particularly true in northern China, where winter temperatures are low. Conventional conduits cannot be bent without a visible crack (they break at low temperatures), making them inconvenient to install and therefore unsuitable for current market demand. To overcome these drawbacks, it is necessary to develop products that can bend freely and easily at low temperatures (approximately 0-5°C) without increasing product formulation costs.

[0003] The prior art discloses a method for preparing high-toughness polyvinyl chloride, which is composed of PVC, CPE, modified nano-calcium carbonate, titanate coupling agent, stearic acid, heat stabilizer, and additive ACR. A large amount of calcium carbonate is added to the polyvinyl chloride product to improve the product's heat resistance, wear resistance, dimensional stability, and stiffness. However, the improvement in toughness is not significant, resulting in the product still being prone to cracking during low-temperature flexure and failing to have good low-temperature air bending performance.

[0004] Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of existing PVC materials, such as the inability to achieve low-temperature (about 0 to 5°C) empty bending without visible cracks and the lack of good low-temperature empty bending performance, and to provide a PVC toughening agent that significantly improves the flexibility and bending deformation ability of PVC and has good low-temperature empty bending performance.

[0006] Another object of the present invention is to provide a high-toughness PVC material.

[0007] Another object of the present invention is to provide a method for preparing a high-toughness PVC material.

[0008] Another object of the present invention is to provide a high-toughness PVC material for use in the preparation of PVC electrical conduits.

[0009] Another object of the present invention is to provide a PVC electrical conduit.

[0010] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0011] A PVC toughening agent is obtained by blending organic silicon oligomer, surface activated nano calcium carbonate, oxidized polyethylene wax and polyacrylic acid resin.

[0012] It is obtained by blending organic silicon oligomer, surface activated nano calcium carbonate, oxidized polyethylene wax and polyacrylic acid resin.

[0013] The mass ratio of organic silicon oligomer, surface activated nano calcium carbonate, oxidized polyethylene wax and polyacrylic acid resin is 3:2-3:1.5-2.5:3-4;

[0014] The organic silicon oligomer is an ethoxy-containing organic silicon oligomer obtained by polymerizing monomethyltriethoxysilane, dimethyldiethoxysilane and monophenyltriethoxysilane.

[0015] Among them, it should be noted that:

[0016] The PVC toughening agent of the present invention contains siloxane groups in its molecular structure. These groups can react with chlorine atoms on the PVC molecular chain to form a highly flexible structure through chemical bonding, thereby improving the flexibility and bending deformation ability of PVC, especially low-temperature toughness, while also having good flame retardant and electrical properties.

[0017] The molecular structure of the PVC toughening agent of the present invention is not only well compatible with the PVC matrix and can be more evenly dispersed in the PVC matrix, but also can form a siloxane-based cross-linked network between the PVC molecular chains. These cross-linked networks can make the PVC molecular chains more tightly combined together, thereby improving the overall toughness and impact resistance of the PVC material, especially the low-temperature performance.

[0018] The PVC toughening agent of the present invention also contains surface-activated nano-calcium carbonate. The activated nano-calcium carbonate particles are uniform and have a small particle size. They are evenly dispersed between PVC molecular chains. After being treated with stearic acid monoglyceride, the interfacial bonding effect with the PVC molecular chain is enhanced, which significantly improves the toughness of the material. The product can not only ensure the compressive performance of the product but also greatly improve the low-temperature flexibility of the product, so that the product will not break when bent at a low temperature (0°C). The product toughness is better than the technical indicators specified in relevant standards, and the product can be widely used in construction engineering operations operated at low temperatures.

[0019] Preferably, the mass ratio of the organosilicon oligomer, the surface-activated nano-calcium carbonate, the oxidized polyethylene wax, and the polyacrylic acid resin is 3:2:2:3.

[0020] In a specific embodiment, preferably, the surface-activated nano-calcium carbonate is obtained by reacting nano-calcium carbonate and stearic acid monoglyceride.

[0021] In a specific embodiment, the preparation method of the surface-activated nano-calcium carbonate of the present invention can be referred to as follows:

[0022] Add 2 to 5 parts of stearic acid monoglyceride to every 100 parts of nano-calcium carbonate and stir at high speed, react at 80 to 90°C, then stir and cool to room temperature to obtain surface-activated nano-calcium carbonate. The reaction temperature is more preferably 85°C.

[0023] In a specific embodiment, preferably, the mass ratio of monomethyltriethoxysilane, dimethyldiethoxysilane and monophenyltriethoxysilane is: 1-3:0.5-2:1, more preferably 2-3:1-2:1, and more preferably 3:2:1.

[0024] The synthesis method of the organosilicon oligomer of the present invention may be a conventional synthesis method in the art, for example, the specific method may be referred to as follows:

[0025] Monomethyltriethoxysilane, dimethyldiethoxysilane and monophenyltriethoxysilane are uniformly mixed, and catalytic polymerization reaction is carried out at 75-85° C. for 2.5-3 hours to prepare an organosilicon oligomer.

[0026] During the synthesis process, a catalyst is required to promote the polymerization reaction. Different catalysts can be selected, such as acids, bases, or other organic compounds. For example, a hydrochloric acid aqueous solution containing dehydrated water and hydrochloric acid (volume ratio of 1:2) can be used as a catalyst to promote the polymerization reaction. Start by adding 80-120 mL of the mixture of water and hydrochloric acid dropwise, controlling the reaction temperature to be stable. After the addition is complete, maintain the temperature and continue the reaction for 2-3 hours.

[0027] After the reaction is completed, the ethanol and part of the water generated by the reaction are distilled off, for example, by distilling at normal pressure followed by distilling at reduced pressure, and the temperature is lowered to room temperature to obtain an ethoxy-containing organosilicon oligomer.

[0028] The present invention further specifically protects a high-toughness PVC material comprising the following components in parts by weight:

[0029] 100 parts of polyvinyl chloride, 35-45 parts of ultrafine activated calcium carbonate, 0.8-1.5 parts of toughening agent, 8-12 parts of anti-impact agent, 0-8.5 parts of other additives,

[0030] Wherein, the toughening agent is the PVC toughening agent.

[0031] Among them, it should be noted that:

[0032] The ultrafine active calcium carbonate of the present invention refers to calcium carbonate with a particle size between 0.02 and 0.1 μm.

[0033] In a specific embodiment, other additives in the high-toughness PVC material of the present invention can be added according to actual needs. For example, in parts by weight, the other additives include the following components:

[0034] 4-5.5 parts of calcium zinc stabilizer, 1-1.5 parts of lubricant, and 1-2 parts of titanium dioxide.

[0035] The high-toughness PVC material of the present invention has strong toughness and is not easily damaged when bent during construction at a relatively low temperature (0° C.). The chlorine content of the PVC is 53-58%, and the material has good flame retardancy and insulation properties.

[0036] Preferably, the following components are included in parts by weight:

[0037] 100 parts of polyvinyl chloride, 35-45 parts of ultrafine active calcium carbonate, 0.8-1.5 parts of toughening agent, 8-12 parts of anti-impact agent, and 0-8.5 parts of other additives.

[0038] The present invention further specifically protects a method for preparing a high-toughness PVC material, comprising the following steps:

[0039] S1: Mix the components at 110-120°C and reduce the temperature to 30-40°C to obtain the material to be used;

[0040] S2: The material to be used in step S1 is put into an extruder for plasticization, and then extruded into shape at an extrusion temperature of 150-200°C.

[0041] The present invention also specifically protects the application of a high-toughness PVC material in a PVC electrical casing.

[0042] The present invention also specifically protects a PVC electrical casing, which is prepared from the high-toughness PVC material.

[0043] The high-toughness PVC material of the present invention not only has good low-temperature empty bending performance, but also has good mechanical properties and electrical properties, and can be widely used in the preparation of PVC electrical casing.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The PVC toughening agent of the present invention can form a highly flexible structure with PVC, improving the flexibility and bending deformation capacity of the PVC. It also has excellent compatibility with the PVC matrix and can form a siloxane-based cross-linked network between PVC molecular chains, thereby improving the overall toughness and impact resistance of the PVC material, especially its low-temperature performance. Furthermore, the PVC toughening agent of the present invention also contains surface-activated nano-calcium carbonate, which enhances the interfacial bonding with the PVC molecular chains and significantly improves the material's toughness. This ensures the product's compressive strength and significantly improves its low-temperature flexibility, preventing the product from cracking when bent at low temperatures (0°C).

[0046] The high-toughness PVC material of the present invention has good impact resistance, low-temperature bending resistance and electrical performance, and can be widely used in low-temperature environments. DETAILED DESCRIPTION

[0047] The present invention will be further described below in conjunction with specific embodiments, but the examples do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the examples of the present invention are conventionally purchased raw materials and reagents.

[0048] Monomethyltriethoxysilane, analytical grade, purchased from Shanghai Huazhirun Company;

[0049] Dimethyldiethoxysilane, analytical grade, purchased from Shanghai Huazhirun Company;

[0050] 1,2-diphenyltriethoxysilane, analytical grade, purchased from Shanghai Huazhirun Company;

[0051] Hydrochloric acid, analytical grade, Taiyuan Chemical Plant;

[0052] PVC, SG-5, Xinjiang Zhongtai Chemical Co., Ltd.;

[0053] Calcium zinc stabilizer, JCS-318Y-C, Shandong Jinchangshu New Material Technology Co., Ltd.;

[0054] Nano calcium carbonate, model P270, Guangxi Huana New Material Technology Co., Ltd.;

[0055] Lubricant, YT-95L, Inner Mongolia Yuanji Chemical Co., Ltd.; HY-66, Inner Mongolia Yuanji Chemical Co., Ltd.;

[0056] Anti-impact agent, CPE-135A, Shandong Riko Chemical Co., Ltd.;

[0057] Titanium dioxide, SR-240, Shandong Dongjia.

[0058] Example 1

[0059] A PVC toughening agent is obtained by blending organic silicon oligomer, surface activated nano calcium carbonate, oxidized polyethylene wax and polyacrylic acid resin.

[0060] The mass ratio of organic silicon oligomer, surface activated nano calcium carbonate, oxidized polyethylene wax and polyacrylic acid resin is 3:2:2:3.

[0061] The organosilicon oligomer is an ethoxy-containing organosilicon oligomer obtained by polymerizing monomethyltriethoxysilane, dimethyldiethoxysilane and monophenyltriethoxysilane;

[0062] The surface activated nano calcium carbonate is obtained by reacting nano calcium carbonate and stearic acid monoglyceride.

[0063] The PVC toughening agent of the above embodiment can be prepared by the following method:

[0064] (1) Synthesis of silicone oligomers

[0065] To a four-necked flask equipped with a stirrer, a thermometer, and a condenser reflux apparatus, monomethyltriethoxysilane, dimethyldiethoxysilane, and monophenyltriethoxysilane were added in a mass ratio of 3:2:1.

[0066] Start the stirring device and raise the temperature to 80°C. Start adding 100 mL of a mixture of deionized water and hydrochloric acid (1:2) dropwise. Control the reaction temperature to be stable. After the addition is completed, maintain the temperature and continue the reaction for 2.5 hours.

[0067] After the reaction is completed, the ethanol and part of the water generated by the reaction are distilled off by atmospheric distillation and then by reduced pressure distillation. The temperature is lowered to room temperature to obtain an ethoxy-containing organosilicon oligomer.

[0068] (2) Activation treatment of nano calcium carbonate

[0069] Add 3 parts of stearic acid monoglyceride to every 100 parts of nano calcium carbonate and stir at high speed at 85°C, then stir at low speed and cool to room temperature for use.

[0070] (3) Synthesis of silicon-modified processing toughening agent

[0071] Organic silicon oligomer, activated nano calcium carbonate, oxidized polyethylene wax and polyacrylic acid resin are blended in a ratio of 3:2:2:3 to obtain a PVC toughening agent.

[0072] Example 2

[0073] A high-toughness PVC material comprises the following components calculated in parts by weight:

[0074] 100 parts of polyvinyl chloride, 35 parts of ultrafine activated calcium carbonate, 5.0 g of calcium zinc stabilizer, 1.2 parts of lubricant, 8 parts of impact agent, 1.5 parts of titanium dioxide, and 0.8 part of the PVC toughening agent of Example 1.

[0075] The preparation method of the above-mentioned high-toughness PVC (electrical casing) comprises the following steps:

[0076] The above raw materials were sequentially put into a high-speed mixer (capacity 500L). After the addition was completed, they were first stirred at a low speed (80rpm) for 30 seconds, and then high-speed stirring (500rpm) was started. After the temperature was raised to 115°C, the materials were discharged into a low-speed cold mixing cylinder (capacity 1500L). When the temperature of the cold mixing cylinder dropped by 45°C, the materials were discharged and transported to a conical twin-screw extruder. After plasticization in the extruder (150-200°C), forming in a bracket-type mold, sizing in an immersion cooling water tank, and cutting to a fixed length on a traction cutting machine, the finished high-toughness PVC material was obtained.

[0077] Example 3

[0078] A high-toughness PVC material comprises the following components calculated in parts by weight:

[0079] 100 parts of polyvinyl chloride, 45 parts of ultrafine activated calcium carbonate, 5.0 g of calcium zinc stabilizer, 1.2 parts of lubricant, 12 parts of impact agent, 1.5 parts of titanium dioxide, and 1.5 parts of the PVC toughening agent of Example 1.

[0080] The preparation method of the above-mentioned high-toughness PVC (electrical conduit) comprises the following steps:

[0081] The above raw materials were sequentially put into a high-speed mixer (capacity 500L). After the addition was completed, they were first stirred at a low speed (80rpm) for 30 seconds, and then high-speed stirring (500rpm) was started. After the temperature was raised to 115°C, the materials were discharged into a low-speed cold mixing cylinder (capacity 1500L). When the temperature of the cold mixing cylinder dropped by 45°C, the materials were discharged and transported to a conical twin-screw extruder. After plasticization in the extruder (150-200°C), forming in a bracket-type mold, sizing in an immersion cooling water tank, and cutting to a fixed length on a traction cutting machine, the finished high-toughness PVC material was obtained.

[0082] Example 4

[0083] A high-toughness PVC material comprises the following components calculated in parts by weight:

[0084] 100 parts of polyvinyl chloride, 40 parts of ultrafine activated calcium carbonate, 5.0 g of calcium zinc stabilizer, 1.2 parts of lubricant, 10 parts of impact agent, 1.5 parts of titanium dioxide, and 1.2 parts of the PVC toughening agent of Example 1.

[0085] The preparation method of the above-mentioned high-toughness PVC (electrical casing) comprises the following steps:

[0086] The above raw materials were sequentially put into a high-speed mixer (capacity 500L). After the addition was completed, they were first stirred at a low speed (80rpm) for 30 seconds, and then high-speed stirring (500rpm) was started. After the temperature was raised to 115°C, the materials were discharged into a low-speed cold mixing cylinder (capacity 1500L). When the temperature of the cold mixing cylinder dropped by 45°C, the materials were discharged and transported to a conical twin-screw extruder. After plasticization in the extruder (150-200°C), forming in a bracket-type mold, sizing in an immersion cooling water tank, and cutting to a fixed length on a traction cutting machine, the finished high-toughness PVC material was obtained.

[0087] Example 5

[0088] A high-toughness PVC material comprises the following components calculated in parts by weight:

[0089] 100 parts of polyvinyl chloride, 37.5 parts of ultrafine activated calcium carbonate, 5.0 g of calcium zinc stabilizer, 1.2 parts of lubricant, 10 parts of impact agent, 1.5 parts of titanium dioxide, and 1.0 part of the PVC toughening agent of Example 1.

[0090] The preparation method of the above-mentioned high-toughness PVC (electrical casing) comprises the following steps:

[0091] The above raw materials were sequentially put into a high-speed mixer (capacity 500L). After the addition was completed, they were first stirred at a low speed (80rpm) for 30 seconds, and then high-speed stirring (500rpm) was started. After the temperature was raised to 115°C, the materials were discharged into a low-speed cold mixing cylinder (capacity 1500L). When the temperature of the cold mixing cylinder dropped by 45°C, the materials were discharged and transported to a conical twin-screw extruder. After plasticization in the extruder (150-200°C), forming in a bracket-type mold, sizing in an immersion cooling water tank, and cutting to a fixed length on a traction cutting machine, the finished high-toughness PVC material was obtained.

[0092] Example 6

[0093] A high-toughness PVC material comprises the following components calculated in parts by weight:

[0094] 100 parts of polyvinyl chloride, 42.5 parts of ultrafine activated calcium carbonate, 5.0 g of calcium zinc stabilizer, 1.2 parts of lubricant, 10 parts of impact agent, 1.5 parts of titanium dioxide, and 1.0 part of the PVC toughening agent of Example 1.

[0095] The preparation method of the above-mentioned high-toughness PVC (electrical casing) comprises the following steps:

[0096] The above raw materials were sequentially put into a high-speed mixer (capacity 500L). After the addition was completed, they were first stirred at a low speed (80rpm) for 30 seconds, and then high-speed stirring (500rpm) was started. After the temperature was raised to 115°C, the materials were discharged into a low-speed cold mixing cylinder (capacity 1500L). When the temperature of the cold mixing cylinder dropped by 45°C, the materials were discharged and transported to a conical twin-screw extruder. After plasticization in the extruder (150-200°C), forming in a bracket-type mold, sizing in an immersion cooling water tank, and cutting to a fixed length on a traction cutting machine, the finished high-toughness PVC material was obtained.

[0097] Example 7

[0098] A high-toughness PVC material comprises the following components calculated in parts by weight:

[0099] 100 parts of polyvinyl chloride, 45 parts of 2000 mesh ordinary light calcium carbonate, 5.5g of calcium zinc stabilizer, 1.5 parts of lubricant, 12 parts of impact agent, 1.5 parts of titanium dioxide, and 1.5 parts of the PVC toughening agent of Example 1.

[0100] The preparation method of the above-mentioned high-toughness PVC (electrical casing) comprises the following steps:

[0101] The above raw materials were sequentially put into a high-speed mixer (capacity 500L). After the addition was completed, they were first stirred at a low speed (80rpm) for 30 seconds, and then high-speed stirring (500rpm) was started. After the temperature was raised to 115°C, the materials were discharged into a low-speed cold mixing cylinder (capacity 1500L). When the temperature of the cold mixing cylinder dropped by 45°C, the materials were discharged and transported to a conical twin-screw extruder. After plasticization in the extruder (150-200°C), forming in a bracket-type mold, sizing in an immersion cooling water tank, and cutting to a fixed length on a traction cutting machine, the finished high-toughness PVC material was obtained.

[0102] Example 8

[0103] A high-toughness PVC material comprises the following components calculated in parts by weight:

[0104] 100 parts of polyvinyl chloride, 37.5 parts of ultrafine activated calcium carbonate, 5.0 g of calcium zinc stabilizer, 1.2 parts of lubricant, 10 parts of impact agent, 1.5 parts of titanium dioxide, and 0.5 part of the PVC toughening agent of Example 1.

[0105] The difference from Example 5 is that the amount of the silicon-modified processing toughening agent used is reduced, and only 0.5 parts of the PVC toughening agent of Example 1 is used.

[0106] The preparation method of the above-mentioned high-toughness PVC (electrical casing) comprises the following steps:

[0107] The above raw materials are sequentially put into a high-speed mixer (capacity 500L). After the addition is completed, they are first stirred at a low speed (80rpm) for 30 seconds, and then high-speed stirring (500rpm) is started. After the temperature is raised to 115°C, the materials are discharged into a low-speed cold mixing cylinder (capacity 1500L). When the temperature of the cold mixing cylinder drops by 45°C, the materials are discharged and transported to a conical twin-screw extruder. After plasticization in the extruder (150-200°C), forming in a bracket-type mold, sizing in an immersion cooling water tank, and cutting to a fixed length on a traction cutting machine, the finished high-toughness PVC is obtained.

[0108] Example 9

[0109] A high-toughness PVC material comprises the following components calculated in parts by weight:

[0110] 100 parts of polyvinyl chloride, 42.5 parts of ultrafine activated calcium carbonate, 5.0 g of calcium zinc stabilizer, 1.2 parts of lubricant, 10 parts of impact agent, 1.5 parts of titanium dioxide, and 2.0 parts of the PVC toughening agent of Example 1.

[0111] The difference from Example 6 is that the amount of the silicon-modified processing toughening agent used is increased, and 2.0 parts of the PVC toughening agent of Example 1 is used.

[0112] The preparation method of the above-mentioned high-toughness PVC (electrical casing) comprises the following steps:

[0113] The above raw materials are sequentially put into a high-speed mixer (capacity 500L). After the addition is completed, they are first stirred at a low speed (80rpm) for 30 seconds, and then high-speed stirring (500rpm) is started. After the temperature is raised to 115°C, the materials are discharged into a low-speed cold mixing cylinder (capacity 1500L). When the temperature of the cold mixing cylinder drops by 45°C, the materials are discharged and transported to a conical twin-screw extruder. After plasticization in the extruder (150-200°C), forming in a bracket-type mold, sizing in an immersion cooling water tank, and cutting to a fixed length on a traction cutting machine, the finished high-toughness PVC is obtained.

[0114] Comparative Example 1

[0115] A PVC material comprising the following components calculated in parts by weight:

[0116] 100 parts of polyvinyl chloride, 35 parts of 2000 mesh ordinary light calcium carbonate, 4.0g of calcium zinc stabilizer, 1.0 part of lubricant, 8 parts of anti-impact agent, and 1.5 parts of titanium dioxide.

[0117] The difference from Example 2 is that light calcium carbonate is used and no silicon-modified processing toughening agent is added.

[0118] The preparation method of the above PVC material comprises the following steps:

[0119] The above raw materials are sequentially put into a high-speed mixer (capacity 500L). After the addition is completed, they are first stirred at a low speed (80rpm) for 30 seconds, and then high-speed stirring (500rpm) is started. After the temperature is raised to 115°C, the materials are discharged into a low-speed cold mixing cylinder (capacity 1500L). When the temperature of the cold mixing cylinder drops by 45°C, the materials are discharged and transported to a conical twin-screw extruder. After plasticization in the extruder (150-200°C), forming in a bracket-type mold, sizing in an immersion cooling water tank, and cutting to a fixed length on a traction cutting machine, the finished high-toughness PVC is obtained.

[0120] Comparative Example 2

[0121] A PVC material comprising the following components calculated in parts by weight:

[0122] 100 parts of polyvinyl chloride, 40 parts of ultrafine activated calcium carbonate, 5.0g of calcium zinc stabilizer, 1.2 parts of lubricant, 10 parts of anti-impact agent, and 1.5 parts of titanium dioxide.

[0123] The difference from Example 4 is that no silicon-modified processing toughening agent is used.

[0124] The preparation method of the above PVC material comprises the following steps:

[0125] The above raw materials are sequentially put into a high-speed mixer (capacity 500L). After the addition is completed, they are first stirred at a low speed (80rpm) for 30 seconds, and then high-speed stirring (500rpm) is started. After the temperature is raised to 115°C, the materials are discharged into a low-speed cold mixing cylinder (capacity 1500L). When the temperature of the cold mixing cylinder drops by 45°C, the materials are discharged and transported to a conical twin-screw extruder. After plasticization in the extruder (150-200°C), forming in a bracket-type mold, sizing in an immersion cooling water tank, and cutting to a fixed length on a traction cutting machine, the finished high-toughness PVC is obtained.

[0126] Comparative Example 3

[0127] A PVC toughening agent, characterized in that it is obtained by blending surface-activated nano calcium carbonate, oxidized polyethylene wax, and polyacrylic acid resin.

[0128] The mass ratio of surface activated nano calcium carbonate, oxidized polyethylene wax and polyacrylic acid resin is 2:2:3.

[0129] The surface activated nano calcium carbonate is obtained by reacting nano calcium carbonate and stearic acid monoglyceride.

[0130] The PVC toughening agent of the above embodiment can be prepared by the following method:

[0131] (1) Activation treatment of nano calcium carbonate

[0132] Add 3 parts of stearic acid monoglyceride to every 100 parts of nano calcium carbonate and stir at high speed at 85°C, then stir at low speed and cool to room temperature for use.

[0133] (2) Synthesis of toughening agent

[0134] Activated nano calcium carbonate, oxidized polyethylene wax and polyacrylic acid resin are blended in a ratio of 2:2:3 to obtain a toughening agent.

[0135] A PVC electrical conduit comprises the following components calculated in parts by weight:

[0136] 100 parts of polyvinyl chloride, 35 parts of ultrafine activated calcium carbonate, 4.0g of calcium zinc stabilizer, 1.0 part of lubricant, 8 parts of anti-impact agent, 1.5 parts of titanium dioxide, and 0.8 part of PVC toughening agent.

[0137] The preparation method of the above-mentioned PVC electrical conduit comprises the following steps:

[0138] The above raw materials were sequentially added into a high-speed mixer (capacity 500L). After the addition was completed, they were first stirred at a low speed (80rpm) for 30 seconds, and then high-speed stirring (500rpm) was started. After the temperature was raised to 115°C, the materials were discharged into a low-speed cold mixing cylinder (capacity 1500L). When the temperature of the cold mixing cylinder dropped by 45°C, the materials were discharged and transported to a conical twin-screw extruder. After plasticization in the extruder (150-200°C), forming in a bracket-type mold, sizing in an immersion cooling water tank, and cutting to a fixed length on a traction cutting machine, the finished PVC electrical conduit was obtained.

[0139] Comparative Example 4

[0140] A PVC electrical conduit comprises the following components calculated in parts by weight:

[0141] 100 parts of polyvinyl chloride, 35 parts of ultrafine activated calcium carbonate, 4.0g of calcium zinc stabilizer, 1.0 parts of lubricant, 8 parts of anti-impact agent, 1.5 parts of titanium dioxide, 0.8 parts of PVC toughening agent,

[0142] The PVC toughening agent is a commercially available PVC toughening agent, model CS-100, produced by Shandong Linyi Lanxu New Materials Co., Ltd.

[0143] The preparation method of the above-mentioned PVC electrical conduit comprises the following steps:

[0144] The above raw materials were sequentially added into a high-speed mixer (capacity 500L). After the addition was completed, they were first stirred at a low speed (80rpm) for 30 seconds, and then high-speed stirring (500rpm) was started. After the temperature was raised to 115°C, the materials were discharged into a low-speed cold mixing cylinder (capacity 1500L). When the temperature of the cold mixing cylinder dropped by 45°C, the materials were discharged and transported to a conical twin-screw extruder. After plasticization in the extruder (150-200°C), forming in a bracket-type mold, sizing in an immersion cooling water tank, and cutting to a fixed length on a traction cutting machine, the finished PVC electrical conduit was obtained.

[0145] Result detection

[0146] Relevant performance tests were conducted according to the standard "JG / T3050-1998". Except for the low-temperature air bending test, all other tests were conducted in accordance with the standard and therefore no detailed description is given. The results are shown in Table 1.

[0147] The standard includes bending tests at room temperature and low temperature (-5°C), but the standard requires that a spring be inserted into the electrical conduit before bending. If the spring is not inserted, the electrical conduit will break at low temperature (0°C), which cannot meet the actual use needs in cold northern regions. The low-temperature empty bending (0°C) of the present invention does not require an inner spring and is directly bent. This bending test is more in line with the low-temperature use environment in northern regions. The addition of this test is to highlight that the electrical conduit of the present invention has excellent low-temperature toughness and can meet the actual needs of the northern market.

[0148] Among them, the testing standard for impact performance is JG / T3050-1998.

[0149] The specific method for testing low-temperature empty bending is to condition the wire at low temperature (0°C) for 4 hours, then remove it and quickly bend it without an inner spring. The standard includes bending tests at room temperature and low temperature (-5°C), but the standard uses a spring inside the electrical conduit before bending. The difference between the two lies in the presence or absence of the inner spring.

[0150] The oxygen index is determined according to GB / T 2406, with the sample taken directly from the casing; and the technical requirements are as specified in GB 50222.

[0151] The test standard for electrical performance is: the test standard is JG / T3050-1998.

[0152] Table 1 Test results

[0153] As shown in Table 1, after adding the PVC toughening agent of the present invention, the bending performance of the PVC electrical casing at low temperature (0°C) is improved. When the addition amount is small, for example, 0.5 parts is added in Example 8, one out of 10 pieces of low-temperature bending will break. When the addition amount is above 0.8 parts, all the pieces pass the low-temperature bending without breaking or cracking. This shows that the PVC toughening agent of the present invention can form a highly flexible structure with PVC, thereby improving the flexibility and bending deformation ability of PVC, especially the low-temperature performance. It can not only ensure the compressive performance of the product but also greatly improve the low-temperature flexibility of the product, so that the product will not break when bent at low temperature (0°C).

[0154] When no PVC toughening agent was added to Comparative Example 1 and Comparative Example 2, all the samples were broken upon bending at low temperature.

[0155] The toughening agent of the PVC material of Comparative Example 3 does not contain silicone oligomers, and the low-temperature bending improvement of the PVC electrical conduit is very limited. Only 2 of the 10 tested electrical conduits were not broken.

[0156] In Comparative Example 4, when a common commercially available PVC toughening agent was added, the low-temperature bending improvement was also limited, and only 3 out of 10 tested electrical conduits were not broken.

[0157] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A PVC toughening agent, characterized in that: It is obtained by blending organic silicon oligomer, surface activated nano calcium carbonate, oxidized polyethylene wax and polyacrylic acid resin. The mass ratio of organic silicon oligomer, surface activated nano calcium carbonate, oxidized polyethylene wax and polyacrylic acid resin is 3:2-3:1.5-2.5:3-4; The organic silicon oligomer is an ethoxy-containing organic silicon oligomer obtained by polymerizing monomethyltriethoxysilane, dimethyldiethoxysilane and monophenyltriethoxysilane.

2. The PVC toughening agent according to claim 1, characterized in that: The surface activated nano calcium carbonate is obtained by reacting nano calcium carbonate and stearic acid monoglyceride.

3. The PVC toughening agent according to claim 1, characterized in that: The mass ratio of the monomethyltriethoxysilane, dimethyldiethoxysilane and monophenyltriethoxysilane is 1-3:0.5-2:

1.

4. The PVC toughening agent according to claim 1, characterized in that: The preparation method of the organosilicon oligomer is as follows: Monomethyltriethoxysilane, dimethyldiethoxysilane and monophenyltriethoxysilane are uniformly mixed, and catalytic polymerization reaction is carried out at 75-85° C. for 2.5-3 hours to prepare an organosilicon oligomer.

5. A high-toughness PVC material, characterized in that: In parts by weight, it includes the following components: 100 parts of polyvinyl chloride, 35-45 parts of ultrafine activated calcium carbonate, 0.8-1.5 parts of toughening agent, 8-12 parts of anti-impact agent, 0-8.5 parts of other additives, Wherein, the toughening agent is the PVC toughening agent according to any one of claims 1 to 4.

6. The high-toughness PVC material according to claim 5, characterized in that: In parts by weight, it includes the following components: 100 parts of polyvinyl chloride, 37-43 parts of ultrafine activated calcium carbonate, 1.0-1.2 parts of toughening agent, 8-12 parts of anti-impact agent, and 0-8.5 parts of other additives.

7. The high-toughness PVC material according to claim 5, characterized in that: In parts by weight, the other additives include the following components: 4-5.5 parts of calcium zinc stabilizer, 1-1.5 parts of lubricant, and 1-2 parts of titanium dioxide.

8. A method for preparing the high-toughness PVC material according to any one of claims 5 to 7, characterized in that: The steps include: S1: Mix the components at 110-120°C and reduce the temperature to 30-40°C to obtain the material to be used; S2: Put the unused material in step S1 into an extruder for plasticization, and then extrude it into shape, with the extrusion temperature being 150-200°C.

9. Use of the high-toughness PVC material according to any one of claims 5 to 7 in PVC electrical conduits.

10. A PVC electrical conduit, characterized in that: It is prepared from the high-toughness PVC material described in any one of claims 5 to 7.

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