A HPVC square power corrugated pipe

Abstract

The invention discloses an HPVC square power corrugated pipe, belonging to the technical field of cable material processing. The invention comprises a composite HPVC, a core-shell structure modifier and related additives. The high-strength HPVC is modified by acrylonitrile and maleic anhydride to obtain a solid composite HPVC, the stability of a plastic substrate under a non-polar solvent and heat is improved, polybutyl acrylate is used as a core phase, acrylamide is used as a cross-linking monomer, and hexachlorocyclotriphosphazene is coated on an outer layer to obtain a toughened and flame-retardant core-shell structure modifier. At the same time, the reaction between the core-shell structure modifier and the redundant functional groups on the surface of the composite HPVC is utilized to solve the technical problem of poor compatibility between the HPVC and the core-shell structure modifier.

Description

Technical Field

[0001] The invention relates to the technical field of cable material processing, in particular to an HPVC square power corrugated pipe. Background Art

[0002] The power corrugated pipe is a pipe used to protect cables. It is named for its unique corrugated structure, which gives it excellent flexibility and pressure resistance, solving the difficulties of trenchless construction in narrow spaces and adapting to the current needs of urban power cable trenchless underground transformation projects that have many restrictions on the impact on the surrounding environment; however, power cables laid in underground environments must not only have certain mechanical properties and flame retardancy, but also have stability in thermal environments and various non-polar and polar solvents to ensure long-term and stable operation of the power cables.

[0003] Patent application CN103421240A discloses a square single-wall corrugated pipe material for electric power, including homopolymer polypropylene powder, block copolymer polypropylene powder, hollow glass microspheres and related additives, maleic anhydride grafted polypropylene compatibilizer, forming a coating film on the surface of the hollow glass microspheres to improve its own dispersibility and compatibility, and using EPDM rubber as a toughening agent for the corrugated pipe material; however, homopolymer polypropylene powder and block copolymer polypropylene powder have poor stability, are easy to age, and have poor weather resistance and corrosion resistance, resulting in the corrugated pipe material prepared therefrom being unsuitable for laying in an underground corrosive environment, and need to be replaced with a plastic with better weather resistance and corrosion resistance as the base material of the corrugated pipe material; at the same time, conventional plastics have poor compatibility with rubber materials such as EPDM, and rubber materials should not be directly added to the above base materials for direct toughening.

[0004] In view of the technical defects in this aspect, a solution is now proposed. Summary of the invention

[0005] The object of the present invention is to provide an HPVC square power corrugated pipe, which is used to solve the problem that the plastic used to prepare the power corrugated pipe in the prior art has poor stability and flame retardancy. In addition, when rubber material is added to the plastic for toughening, there is also a technical problem of poor compatibility between the plastic and the rubber material.

[0006] The purpose of the present invention can be achieved by the following technical solution: A HPVC square power corrugated pipe, comprising the following components in parts by weight:

[0007] 100 parts of composite HPVC, 20-30 parts of core-shell structure modifier, 0.1-0.3 parts of antioxidant, 0.5 parts of lubricant, 3-5 parts of stabilizer and 0.5-1 parts of light shielding agent;

[0008] The preparation method of the composite HPVC comprises the following steps:

[0009] A1, HPVC, acrylonitrile, tetrahydrofuran, emulsifier and composite initiator are mixed and added into a high-pressure reactor;

[0010] A2, replacing all the air in the autoclave with nitrogen, then evacuating, and then pressing maleic anhydride into the autoclave to obtain a reaction system; adjusting the temperature of the autoclave to 60-65° C., and the reaction system undergoes a polymerization reaction; during the polymerization reaction, sampling and analysis are performed every 30 minutes, and when the conversion rate of the polymerization reaction is detected to be 85-90%, the reaction is continued for 1 hour, and then unreacted HPVC and maleic anhydride are discharged, and then the material is discharged to obtain a polymerized HPVC emulsion;

[0011] A3. The polymerized HPVC emulsion is washed with an ethanol solution to obtain a purified polymerized HPVC emulsion; the purified polymerized HPVC emulsion is dried at 80-85° C. to a constant weight to obtain a solid composite HPVC.

[0012] With tetrahydrofuran as solvent, HPVC, acrylonitrile and maleic anhydride are mixed and polyaddition reaction is carried out by using an emulsifier under the action of a composite initiator to obtain a polymerized HPVC emulsion. The polymerized HPVC emulsion is treated by a series of processes to obtain a solid composite HPVC.

[0013] The reaction formula of HPVC, maleic anhydride and acrylonitrile to obtain composite HPVC is as follows:

[0014]

[0015] Among them, the value of n is 2200-2500.

[0016] Furthermore, in step A1, ammonium persulfate and potassium persulfate are uniformly mixed in a mass ratio of 1:1 to obtain a composite initiator, and the emulsifier is sodium alkylbenzene sulfonate; the amount ratio of the HPVC, acrylonitrile, tetrahydrofuran, emulsifier and composite initiator is 750g:100-200g:2000g:1-2g:0.1-0.5g; in step A3, the concentration of the ethanol solution is 5%wt.

[0017] Furthermore, the preparation method of the core-shell structure modifier comprises the following steps:

[0018] B1, mixing deionized water, electrolyte and emulsifier and stirring until the electrolyte and emulsifier are completely dissolved in the deionized water to obtain an additive solution;

[0019] B2, adding butyl acrylate, acrylamide and initiator to the auxiliary agent solution, reacting at 65-75°C for 2-3h to obtain a cross-linked polybutyl acrylate emulsion;

[0020] B3, hexachlorocyclotriphosphazene and 1,4-dioxane are mixed evenly to obtain a hexachlorocyclotriphosphazene solution; anhydrous potassium carbonate and cross-linked polybutyl acrylate emulsion are mixed to obtain a composite emulsion; the hexachlorocyclotriphosphazene solution is then added dropwise to the composite emulsion at a rate of 1 mL / min, and after the addition is completed, the reaction is carried out at 20-30° C. for 2-3 hours to obtain a polymer emulsion;

[0021] B4. Demulsify the polymer emulsion, discard the upper liquid, and obtain a colloid; wash the colloid three times with water, and then vacuum dry at 50-60° C. to obtain a core-shell structure modifier.

[0022] With deionized water as solvent, potassium carbonate as electrolyte, sodium dodecyl sulfate as emulsifier, potassium persulfate as initiator and butyl acrylate as monomer, polyaddition reaction occurs to prepare polybutyl acrylate. With polybutyl acrylate as core phase, a certain amount of crosslinking monomer acrylamide is added during the polyaddition reaction to obtain crosslinked polybutyl acrylate.

[0023] The reaction formula of butyl acrylate and acrylamide to obtain cross-linked polybutyl acrylate is as follows:

[0024]

[0025] Acrylamide is used as a grafting site, and a hexachlorocyclotriphosphazene solution is continuously added to the cross-linked polybutyl acrylate emulsion, so that a layer of flame retardant hexachlorocyclotriphosphazene is continuously coated on the core phase. A core-shell structure modifier having a core phase and a core wall is prepared by a layer-by-layer polymerization method.

[0026] The reaction formula of hexachlorocyclotriphosphazene and cross-linked polybutyl acrylate is as follows:

[0027]

[0028] Furthermore, in step B1, the electrolyte is potassium carbonate, the emulsifier is sodium dodecyl sulfate, and the usage ratio of deionized water, electrolyte and emulsifier is 150g:1-2g:2-3g; in step B2, the initiator is potassium persulfate, and the usage ratio of butyl acrylate, acrylamide and initiator is 100g:5-10g:0.5g.

[0029] Furthermore, in step B3, the usage ratio of hexachlorocyclotriphosphazene and 1,4-dioxane is 5-10 g:50 mL; the usage ratio of anhydrous potassium carbonate, cross-linked polybutyl acrylate emulsion and hexachlorocyclotriphosphazene solution is 20 g:50-60 g:10-20 mL.

[0030] Furthermore, the antioxidant is any one of antioxidant 4010, antioxidant DPPD or antioxidant DNP; the lubricant is any one of paraffin, stearic acid or stearic acid ester; the stabilizer is silicic acid co-precipitated lead silicate; the light shielding agent is any one of carbon black, zinc oxide or titanium dioxide.

[0031] The present invention also provides a method for preparing a HPVC square power corrugated pipe, comprising the following steps:

[0032] S1. Add the composite HPVC, core-shell structure modifier, antioxidant, lubricant, stabilizer and light shielding agent into a high-speed mixer, and mix at 2000-3000 r / min for 10-20 min to obtain a mixed material;

[0033] S2. The mixed material is added into an open mill, melted, sheared and mixed to obtain a sample; the sample is then placed in a vacuum flat vulcanizer for molding to obtain an HPVC square power bellows material; the HPVC square power bellows material is added into an extruder and extruded to obtain a PVC square power bellows.

[0034] Furthermore, in step S2, the vulcanization temperature is 150-160°C, the vulcanization pressure is 5-10MPa, and the molding time is 10-20min; and the vacuum degree of the extrusion molding machine is 0.02-0.05MPa.

[0035] The present invention has the following beneficial effects:

[0036] 1. The average polymer of the HPVC resin selected in the present invention is 2200-2500, and the HPVC resin with a high degree of polymerization has the advantages of high electrical insulation, chemical corrosion resistance and strong mechanical properties; in order to further improve the mechanical properties of HPVC itself, the highly polymerized HPVC resin is modified with maleic anhydride and acrylonitrile, the molecules of acrylonitrile contain cyano groups, and maleic anhydride contains anhydride groups. In the composite HPVC resin modified with polar monomers, the interaction between macromolecules is stronger, making it more stable under non-polar solvents and heat, expanding the application range of the prepared power bellows, and the anhydride functional groups and nitrile groups on the surface of the composite HPVC have high reactivity, which can react with chloride ions on the surface of the core-shell structure modifier, thereby improving the compatibility of the composite HPVC resin with the core-shell structure modifier; the addition of the core-shell structure modifier in the present invention can play a role equivalent to that of a plasticizer, thereby improving the elasticity and flexibility of the composite HPVC.

[0037] 2. Butyl acrylate is prepared by emulsion polymerization to obtain polybutyl acrylate. As a rubber matrix, polybutyl acrylate can provide toughening and aging resistance for HPVC. In addition, the glass transition temperature of polybutyl acrylate is low, which can improve the flexibility of HPVC resin and make it suitable for processing. However, the compatibility between polybutyl acrylate and composite HPVC with high polarity is poor. By grafting cross-linking monomer acrylamide on the surface of polybutyl acrylate, the rubber particles can be well dispersed in the HPVC matrix, and the excess amino functional groups of acrylamide can effectively disperse the rubber particles in the HPVC matrix. The group enables it to undergo a nucleophilic substitution reaction with hexachlorocyclotriphosphazene, thereby connecting the flame retardant monomer to the outer layer of polybutyl acrylate, so that the prepared core-shell structure modifier has flame retardant properties and acts as a flame retardant auxiliary agent; from a process perspective, the present invention adopts an emulsion expansion two-step method to prepare polybutyl acrylate with a core-shell structure, butyl acrylate undergoes an addition polymerization reaction to obtain core-phase polybutyl acrylate, and then uses acrylamide, a cross-linking monomer, as a medium to continue the addition polymerization reaction, and the hexachlorocyclotriphosphazene is covered on the outer layer to form a core-shell structure modifier with layer-by-layer coating and gradually increasing particle size.

[0038] 3. Using composite HPVC as the resin base material, the core-shell structure modifier as a complex of flame retardant, compatibilizer and toughening agent, and adding antioxidant, lubricant, stabilizer and light shielding agent as related additives, all the materials for the prepared HPVC square power corrugated pipe are obtained, and the above-mentioned mixed materials are subjected to plasticization, vulcanization and other processes to prepare PVC square power corrugated pipe. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0040] This embodiment provides a method for preparing a composite HPVC for an HPVC square power corrugated pipe, comprising the following steps:

[0041] A1, ammonium persulfate and potassium persulfate are mixed uniformly in a mass ratio of 1:1 to obtain a composite initiator. A 5L stainless steel autoclave is selected, the autoclave is equipped with a precision pressure gauge, a thermocouple and a stirring paddle, and the autoclave is provided with an automatic temperature control system; 750g of HPVC, 100g of acrylonitrile, 2000g of tetrahydrofuran, 1g of an emulsifier sodium alkylbenzene sulfonate and 0.1g of the composite initiator are sequentially added into the autoclave.

[0042] A2. All the air in the autoclave is replaced with nitrogen, and then the autoclave is completely evacuated, and 200-250 g of maleic anhydride is pressed into the autoclave to obtain a reaction system; the temperature of the autoclave is adjusted to 60° C. by using an automatic temperature control system, and the reaction system is mixed and stirred at 200 r / min to perform a polymerization reaction; during the polymerization reaction, sampling and analysis are performed every 30 minutes until the conversion rate of the polymerization reaction is 85%, and the reaction is continued for 1 hour, unreacted HPVC and maleic anhydride are discharged, and then the material is discharged to obtain a polymerized HPVC emulsion.

[0043] A3. The polymerized HPVC emulsion is washed three times with a 5%wt ethanol solution to remove impurities, thereby obtaining a purified polymerized HPVC emulsion; the purified polymerized HPVC emulsion is dried at 80°C to a constant weight to obtain a solid product, namely, the composite HPVC. Example 2

[0044] This embodiment provides a method for preparing a composite HPVC for an HPVC square power corrugated pipe, comprising the following steps:

[0045] A1, ammonium persulfate and potassium persulfate are mixed uniformly in a mass ratio of 1:1 to obtain a composite initiator. A 5L stainless steel autoclave is selected, the autoclave is equipped with a precision pressure gauge, a thermocouple and a stirring paddle, and the autoclave is provided with an automatic temperature control system; 750g of HPVC, 150g of acrylonitrile, 2000g of tetrahydrofuran, 1.5g of emulsifier sodium alkylbenzene sulfonate and 0.3g of the composite initiator are sequentially added into the autoclave.

[0046] A2. All the air in the autoclave was replaced with nitrogen, and then the autoclave was completely evacuated, and 220 g of maleic anhydride was pressed into the autoclave to obtain a reaction system; the temperature of the autoclave was adjusted to 62° C. by using an automatic temperature control system, and the reaction system was mixed and stirred at 250 r / min to perform a polymerization reaction; during the polymerization reaction, sampling and analysis were performed every 30 minutes until the conversion rate of the polymerization reaction was 88%, and the reaction was continued for 1 hour, unreacted HPVC and maleic anhydride were discharged, and then the material was discharged to obtain a polymerized HPVC emulsion.

[0047] A3. The polymerized HPVC emulsion is washed three times with a 5%wt ethanol solution to remove impurities, thereby obtaining a purified polymerized HPVC emulsion; the purified polymerized HPVC emulsion is dried at 82°C to a constant weight to obtain a solid product, namely, the composite HPVC. Example 3

[0048] This embodiment provides a method for preparing a composite HPVC for an HPVC square power corrugated pipe, comprising the following steps:

[0049] A1, ammonium persulfate and potassium persulfate are mixed uniformly in a mass ratio of 1:1 to obtain a composite initiator. A 5L stainless steel autoclave is selected, the autoclave is equipped with a precision pressure gauge, a thermocouple and a stirring paddle, and the autoclave is provided with an automatic temperature control system; 750g of HPVC, 200g of acrylonitrile, 2000g of tetrahydrofuran, 2g of an emulsifier sodium alkylbenzene sulfonate and 0.5g of the composite initiator are sequentially added into the autoclave.

[0050] A2. Replace all the air in the autoclave with nitrogen, then completely evacuate the autoclave, pressurize 250 g of maleic anhydride into the autoclave to obtain a reaction system; use an automatic temperature control system to adjust the temperature of the autoclave to 65° C., mix and stir at 300 r / min, and perform polymerization in the reaction system; during the polymerization reaction, take samples and analyze them every 30 minutes until the conversion rate of the polymerization reaction reaches 90%, continue the reaction for 1 hour, discharge unreacted HPVC and maleic anhydride, and then discharge to obtain a polymerized HPVC emulsion.

[0051] A3. The polymerized HPVC emulsion is washed three times with a 5%wt ethanol solution to remove impurities, thereby obtaining a purified polymerized HPVC emulsion; the purified polymerized HPVC emulsion is dried at 85°C to a constant weight to obtain a solid product, namely, the composite HPVC. Example 4

[0052] This embodiment provides a method for preparing a core-shell structure modifier for HPVC square power corrugated pipe, comprising the following steps:

[0053] B1. Select a 500mL four-necked flask, set a stirring paddle in the four-necked flask, then add 150g of deionized water, 1g of electrolyte potassium carbonate and 2g of emulsifier sodium dodecyl sulfate into the four-necked flask, stir at a low speed of 100r / min until the electrolyte and emulsifier are completely dissolved in the deionized water to obtain an auxiliary solution; then add 100g of butyl acrylate, 5g of acrylamide and 0.5g of initiator potassium persulfate into the four-necked flask, transfer the four-necked flask to an oil bath, set the temperature to 65°C, the speed of the stirring paddle to 200r / min, mix and react for 2h to obtain a cross-linked polybutyl acrylate emulsion.

[0054] B2, 5g of hexachlorocyclotriphosphazene and 50mL of 1,4-dioxane were mixed evenly to obtain a hexachlorocyclotriphosphazene solution. A 500mL three-necked flask was selected, a thermometer was set at one end of the three-necked flask, and a constant pressure dropping funnel was set at one end. 20g of anhydrous potassium carbonate and 50g of cross-linked polybutyl acrylate emulsion were added to the three-necked flask to obtain a composite emulsion; 10mL of the hexachlorocyclotriphosphazene solution was then added dropwise to the three-necked flask through a constant pressure dropping funnel, and the dropping rate was 1mL / min; an electric heating jacket was set on the outside of the three-necked flask, and then the three-necked flask was heated to 20°C, reacted for 2h, and the reaction was completed to obtain a polymer emulsion.

[0055] B3. The polymer emulsion is demulsified and the upper liquid is discarded to obtain a colloid; the colloid is washed three times with water and then vacuum dried at 50° C. to obtain a core-shell structure modifier. Example 5

[0056] This embodiment provides a method for preparing a core-shell structure modifier for HPVC square power corrugated pipe, comprising the following steps:

[0057] B1. Select a 500mL four-necked flask, set a stirring paddle in the four-necked flask, then add 150g of deionized water, 2g of electrolyte potassium carbonate and 2.5g of emulsifier sodium dodecyl sulfate into the four-necked flask, stir at a low speed of 100r / min until the electrolyte and emulsifier are completely dissolved in the deionized water to obtain an auxiliary solution; then add 100g of butyl acrylate, 6g of acrylamide and 0.5g of initiator potassium persulfate into the four-necked flask, transfer the four-necked flask to an oil bath, set the temperature to 70°C, the speed of the stirring paddle to 250r / min, mix and react for 2.5h to obtain a cross-linked polybutyl acrylate emulsion.

[0058] B2, 8g of hexachlorocyclotriphosphazene and 50mL of 1,4-dioxane were mixed evenly to obtain a hexachlorocyclotriphosphazene solution. A 500mL three-necked flask was selected, a thermometer was set at one end of the three-necked flask, and a constant pressure dropping funnel was set at one end. 20g of anhydrous potassium carbonate and 55g of cross-linked polybutyl acrylate emulsion were added to the three-necked flask to obtain a composite emulsion; 15mL of the hexachlorocyclotriphosphazene solution was then added dropwise to the three-necked flask through a constant pressure dropping funnel, and the dropping rate was 1mL / min; an electric heating jacket was set on the outside of the three-necked flask, and then the three-necked flask was heated to 25°C, reacted for 2.5h, and the reaction was completed to obtain a polymer emulsion.

[0059] B3. The polymer emulsion is demulsified and the upper liquid is discarded to obtain a colloid; the colloid is washed three times with water and then vacuum dried at 55° C. to obtain a core-shell structure modifier. Example 6

[0060] This embodiment provides a method for preparing a core-shell structure modifier for HPVC square power corrugated pipe, comprising the following steps:

[0061] B1. Select a 500mL four-necked flask, set a stirring paddle in the four-necked flask, then add 150g of deionized water, 2g of electrolyte potassium carbonate and 3g of emulsifier sodium dodecyl sulfate into the four-necked flask, stir at a low speed of 100r / min until the electrolyte and emulsifier are completely dissolved in the deionized water to obtain an auxiliary solution; then add 100g of butyl acrylate, 10g of acrylamide and 0.5g of initiator potassium persulfate into the four-necked flask, transfer the four-necked flask to an oil bath, set the temperature to 75°C, the speed of the stirring paddle to 300r / min, mix and react for 3h to obtain a cross-linked polybutyl acrylate emulsion.

[0062] B2, 10g of hexachlorocyclotriphosphazene and 50mL of 1,4-dioxane were mixed evenly to obtain a hexachlorocyclotriphosphazene solution. A 500mL three-necked flask was selected, a thermometer was set at one end of the three-necked flask, and a constant pressure dropping funnel was set at one end. 20g of anhydrous potassium carbonate and 60g of cross-linked polybutyl acrylate emulsion were added to the three-necked flask to obtain a composite emulsion; then 20mL of the hexachlorocyclotriphosphazene solution was added dropwise to the three-necked flask through a constant pressure dropping funnel, and the dropping rate was 1mL / min; an electric heating jacket was set on the outside of the three-necked flask, and then the three-necked flask was heated to 30°C, reacted for 3h, and the reaction was completed to obtain a polymer emulsion.

[0063] B3. The polymer emulsion is demulsified and the upper liquid is discarded to obtain a colloid; the colloid is washed three times with water and then vacuum dried at 60° C. to obtain a core-shell structure modifier. Example 7

[0064] This embodiment provides a method for preparing a HPVC square power corrugated pipe, comprising the following steps:

[0065] S1. According to parts by weight, 100 parts of the composite HPVC prepared in Example 1, 20 parts of the core-shell structure modifier prepared in Example 4, 0.1 parts of antioxidant 4010, 0.5 parts of lubricant paraffin, 3 parts of stabilizer silicic acid co-precipitated lead silicate and 0.5 parts of light shielding agent carbon black are added into a high-speed mixer and mixed at 2000r / min for 10min to obtain a mixed material.

[0066] S2. Add the mixed material into an open mill, melt and shear mix for 10 minutes, then take it out, the temperature of the open mill is 160°C; then place the sample in a vacuum flat vulcanizer for molding, the vulcanization temperature is 150°C, the vulcanization pressure is 5MPa, and the molding time is 10min, to prepare HPVC square power corrugated pipe material. The HPVC square power corrugated pipe material is added to an extruder to prepare a PVC square power corrugated pipe, and the vacuum degree in the barrel of the extruder is 0.02MPa. Example 8

[0067] This embodiment provides a method for preparing a HPVC square power corrugated pipe, comprising the following steps:

[0068] S1. According to parts by weight, 100 parts of the composite HPVC prepared in Example 2, 25 parts of the core-shell structure modifier prepared in Example 5, 0.2 parts of the antioxidant DPPD, 0.5 parts of the lubricant stearic acid, 4 parts of the stabilizer silicic acid co-precipitated lead silicate and 0.6 parts of the light shielding agent zinc oxide are added into a high-speed mixer, and mixed at 2500r / min for 25min to obtain a mixed material.

[0069] S2. Add the mixed material into an open mill, melt and shear mix for 12 minutes, then take it out, the temperature of the open mill is 165°C; then place the sample in a vacuum flat vulcanizer for molding, the vulcanization temperature is 155°C, the vulcanization pressure is 8MPa, and the molding time is 16min, to prepare HPVC square power corrugated pipe material. The HPVC square power corrugated pipe material is added to an extruder to prepare a PVC square power corrugated pipe, and the vacuum degree in the barrel of the extruder is 0.03MPa. Example 9

[0070] This embodiment provides a method for preparing a HPVC square power corrugated pipe, comprising the following steps:

[0071] S1. According to parts by weight, 100 parts of the composite HPVC prepared in Example 3, 30 parts of the core-shell structure modifier prepared in Example 6, 0.3 parts of the antioxidant DNP, 0.5 parts of the lubricant stearic acid ester, 5 parts of the stabilizer silicic acid co-precipitated lead silicate and 1 part of the light shielding agent titanium dioxide are added to a high-speed mixer and mixed at 3000r / min for 20min to obtain a mixed material.

[0072] S2. Add the mixed material into an open mill, melt and shear mix at 170°C for 15 minutes, then take it out to obtain a sample; then place the sample in a vacuum flat vulcanizer for molding, the vulcanization temperature is 160°C, the vulcanization pressure is 10MPa, and the molding time is 20min, to prepare HPVC square power corrugated pipe material. The HPVC square power corrugated pipe material is added to an extruder to prepare a PVC square power corrugated pipe, and the vacuum degree in the barrel of the extruder is 0.05MPa.

[0073] Comparative Example 1

[0074] Compared with Example 9, in the preparation of the composite HPVC, only maleic anhydride was used for modification, and no acrylonitrile monomer was added.

[0075] Comparative Example 2

[0076] Compared with Example 9, in Comparative Example 1, HPVC was replaced with PVC of equal mass, and PVC was reacted with maleic anhydride and acrylonitrile monomers to prepare a resin base material.

[0077] Comparative Example 3

[0078] Compared with Example 9, in this Comparative Example 1, step B2 is eliminated when preparing the core-shell structure modifier.

[0079] Performance Test:

[0080] 1. According to GB / T-1040 "Determination of tensile properties of plastics", the HPVC square power corrugated pipes prepared in Examples 7-9 were cut into 150mm×150mm×2mm plate-shaped samples, and then the tensile properties of the samples were measured using a microcomputer-controlled electronic universal testing machine at a tensile rate of 200mm / min to determine the tensile strength and elongation at break values.

[0081] 2. According to GB / T-1043-93 “Hard Plastic Simply Supported Beam Impact Test Method”, the notched impact strength test of the HPVC square power bellows prepared in Examples 7-9 was performed using an XCJ-40 impact testing machine.

[0082] 3. According to ISO4589-2 "Plastics - Determination of Combustion Behavior by Oxygen Index Method - Part 2: Room Temperature Test", the HPVC square power corrugated pipe materials prepared in Examples 7-9 were cut into 100mm×6.5mm×3mm test specimens and tested at room temperature using the top surface ignition method. The specific test results are shown in Table 1:

[0083]

[0084] Data Analysis:

[0085] By comparing and analyzing the data in Table 1 above, the HPVC square power corrugated pipes prepared in Examples 7-9 of the present invention have excellent mechanical properties, including high values ​​of tensile strength, elongation at break and notched impact strength; however, in Comparative Example 2, PVC of the same quality is used to replace the HPVC with high-strength performance, so that the tensile strength, elongation at break and notched impact strength values ​​are reduced.

[0086] In Comparative Example 1, the composite HPVC was modified without adding acrylonitrile monomer, which reduced the polarity and rigidity of the molecular chain, and the tensile strength and elongation at break of the product decreased. Theoretically, the composite HPVC should have a reduced toughness due to the reduction of polar functional groups in the molecular chain, which is manifested as a decrease in the notched impact strength value. However, the toughness of the composite HPVC that was not modified with acrylonitrile monomer in the present invention was not significantly reduced, indicating that the core-shell structure modifier can significantly compensate for the toughness of the composite HPVC.

[0087] In Comparative Example 3, when preparing the core-shell structure modifier, hexachlorocyclotriphosphazene was not used to coat the cross-linked polybutyl acrylate, so that the core-shell structure modifier did not have flame retardancy, which was manifested in that the prepared HPVC square power corrugated pipe had poor flame retardancy.

[0088] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

[0089] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0090] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A HPVC square power corrugated pipe, characterized in that: The invention comprises the following components in parts by weight: 100 parts of composite HPVC, 20-30 parts of core-shell structure modifier, 0.1-0.3 parts of antioxidant, 0.5 parts of lubricant, 3-5 parts of stabilizer and 0.5-1 parts of light shielding agent; The preparation method of the composite HPVC comprises the following steps: A1, HPVC, acrylonitrile, tetrahydrofuran, emulsifier and composite initiator are mixed and added into a high-pressure reactor; A2, replacing all the air in the autoclave with nitrogen, then evacuating, and then pressing maleic anhydride into the autoclave to obtain a reaction system; adjusting the temperature of the autoclave to 60-65° C., and the reaction system undergoes a polymerization reaction; during the polymerization reaction, sampling and analysis are performed every 30 minutes, and when the conversion rate of the polymerization reaction is detected to be 85-90%, the reaction is continued for 1 hour, and then unreacted HPVC and maleic anhydride are discharged, and then the material is discharged to obtain a polymerized HPVC emulsion; A3. The polymerized HPVC emulsion is washed with an ethanol solution to obtain a purified polymerized HPVC emulsion; the purified polymerized HPVC emulsion is dried at 80-85° C. to a constant weight to obtain a solid composite HPVC; The preparation method of the core-shell structure modifier comprises the following steps: B1, mixing deionized water, electrolyte and emulsifier and stirring until the electrolyte and emulsifier are completely dissolved in the deionized water to obtain an additive solution; B2, adding butyl acrylate, acrylamide and initiator to the auxiliary agent solution, reacting at 65-75°C for 2-3h to obtain a cross-linked polybutyl acrylate emulsion; B3, hexachlorocyclotriphosphazene and 1,4-dioxane are mixed evenly to obtain a hexachlorocyclotriphosphazene solution; anhydrous potassium carbonate and cross-linked polybutyl acrylate emulsion are mixed to obtain a composite emulsion; the hexachlorocyclotriphosphazene solution is then added dropwise to the composite emulsion at a rate of 1 mL / min, and after the addition is completed, the reaction is carried out at 20-30° C. for 2-3 hours to obtain a polymer emulsion; B4. Demulsify the polymer emulsion, discard the upper liquid, and obtain a colloid; wash the colloid three times with water, and then vacuum dry at 50-60° C. to obtain a core-shell structure modifier.

2. The HPVC square power corrugated pipe according to claim 1, characterized in that: In step A1, ammonium persulfate and potassium persulfate are uniformly mixed in a mass ratio of 1:1 to obtain a composite initiator, and the emulsifier is sodium alkylbenzene sulfonate; the amount ratio of the HPVC, acrylonitrile, tetrahydrofuran, emulsifier and composite initiator is 750g:100-200g:2000g:1-2g:0.1-0.5g; in step A3, the concentration of the ethanol solution is 5%wt.

3. The HPVC square power corrugated pipe according to claim 1, characterized in that: In step B1, the electrolyte is potassium carbonate, the emulsifier is sodium dodecyl sulfate, and the usage ratio of deionized water, electrolyte and emulsifier is 150g:1-2g:2-3g; in step B2, the initiator is potassium persulfate, and the usage ratio of butyl acrylate, acrylamide and initiator is 100g:5-10g:0.5g.

4. The HPVC square power corrugated pipe according to claim 1, characterized in that: In step B3, the usage ratio of hexachlorocyclotriphosphazene and 1,4-dioxane is 5-10 g:50 mL; the usage ratio of anhydrous potassium carbonate, cross-linked polybutyl acrylate emulsion and hexachlorocyclotriphosphazene solution is 20 g:50-60 g:10-20 mL.

5. The HPVC square power corrugated pipe according to claim 1, characterized in that: The antioxidant is any one of antioxidant 4010, antioxidant DPPD or antioxidant DNP; the lubricant is any one of paraffin, stearic acid or n-butyl stearate; the stabilizer is silicic acid co-precipitated lead silicate; the light shielding agent is any one of carbon black, zinc oxide or titanium dioxide.

6. A method for preparing an HPVC square power corrugated pipe, used for an HPVC square power corrugated pipe as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Add the composite HPVC, core-shell structure modifier, antioxidant, lubricant, stabilizer and light shielding agent into a high-speed mixer, and mix at 2000-3000 r / min for 10-20 min to obtain a mixed material; S2. The mixed material is added into an open mill, melted, sheared and mixed to obtain a sample; the sample is then placed in a vacuum flat vulcanizer for molding to obtain an HPVC square power bellows material; the HPVC square power bellows material is added into an extruder and extruded to obtain a PVC square power bellows.

7. The method for preparing a HPVC square power corrugated pipe according to claim 6, characterized in that: In step S2, the vulcanization temperature is 150-160°C, the vulcanization pressure is 5-10MPa, and the molding time is 10-20min; the vacuum degree of the extrusion molding machine is 0.02-0.05MPa.

Images