Flame-retardant impact-resistant CPVC power pipe material and preparation method thereof

Abstract

This invention discloses a flame-retardant and impact-resistant CPVC power pipe material and its preparation method, belonging to the technical field of acrylic rubber materials. Specifically, it comprises the following components by weight: 70-80 parts CPVC, 8-10 parts ACM-g-MAH, 9-11 parts core-shell filler, and 3-5 parts additives. This invention uses Mg / Al / molybdenum composite metal salt particles as the core, activated by KH-570, and then combined with methyl methacrylate, glycidyl methacrylate, and octavinyl-POSS to construct a core-shell filler. This filler, along with ACM-g-MAH, reinforces the CPVC main resin, effectively improving the oxygen index, notched impact strength, and Vicat softening temperature of the flame-retardant and impact-resistant CPVC power pipe material, while also reducing the material's smoke density.

Description

Technical Field

[0001] This invention relates to the field of acrylic rubber materials technology, specifically to a flame-retardant and impact-resistant CPVC power pipe material and its preparation method. Background Technology

[0002] Acrylic rubber (CPVC) is a thermoplastic engineering plastic obtained by further chlorination of polyvinyl chloride. It has a high chlorine content, good flame retardancy, corrosion resistance and electrical insulation, and is therefore widely used in power pipes, communication sheathing pipes and building supporting pipes.

[0003] However, CPVC has a relatively rigid molecular chain and insufficient toughness, making it prone to brittle fracture when subjected to external impact. CPVC power pipes are prone to cracking and splitting, making it difficult to meet the requirements of high-impact applications. On the other hand, although CPVC has a certain intrinsic flame retardancy, it may still release a lot of smoke and acidic gases during combustion or thermal decomposition, which is not conducive to improving the overall fire safety performance of the material. Traditional technology modifies CPVC by adding smoke suppressants, but the addition of smoke suppressants or inorganic fillers can easily lead to increased brittleness and poor interfacial compatibility. While conventional toughening agents can improve impact performance, they reduce the material's heat resistance, Vicat softening temperature, and dimensional stability. Therefore, a solution is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a flame-retardant and impact-resistant CPVC power pipe material and its preparation method, so as to solve the technical defects mentioned in the background art.

[0005] The objective of this invention can be achieved through the following technical solution: a flame-retardant and impact-resistant CPVC power pipe material, comprising the following components by weight: 70-80 parts of CPVC, 8-10 parts of ACM-g-MAH, 9-11 parts of core-shell filler, and 3-5 parts of additives;

[0006] The ACM-g-MAH is an acrylic rubber modified with maleic anhydride;

[0007] The core layer of the core-shell filler is a composite metal salt particle containing molybdenum, magnesium and aluminum. The shell layer is obtained by surface modification of the composite metal salt particle with KH-570, followed by emulsification polymerization using octavinyl-POSS, methyl methacrylate and glycidyl methacrylate as the shell solution.

[0008] Furthermore, ACM-g-MAH is obtained through the following steps:

[0009] A1. Add acrylic rubber to a drum dryer, raise the temperature of the drum dryer to 60-70℃, spray the finishing liquid into the drum dryer, and after spraying, dry to remove the solvent to obtain the premix.

[0010] A2. Add the premixed material to a twin-screw extruder, melt mix for 3-5 minutes, then extrude. After cooling, pelletizing, and crushing, obtain crude ACM-g-MAH. Extract the crude ACM-g-MAH to obtain ACM-g-MAH.

[0011] Furthermore, in step A1, the solid-liquid ratio of the acrylate rubber and the modifying liquid is 10:1. The modifying liquid is composed of maleic anhydride, dicumyl peroxide, triallyl isocyanurate, antioxidant 1010, and acetone in a ratio of 30g:4g:2g:1g:60mL. The particle size of the acrylate rubber is 10-100μm, and the rotation speed of the drum dryer is 20-50r / min.

[0012] Furthermore, in step A2, the temperatures of the five temperature zones of the twin-screw extruder are 160℃, 165℃, 165℃, 165℃, and 170℃ respectively, the die temperature is 170℃, and the particle size of the ACM-g-MAH crude product is 0.1-0.5mm.

[0013] Further, the extraction operation is as follows: crude ACM-g-MAH is mixed with acetone at a solid-liquid ratio of 1:3-5, the reaction system is heated to reflux and kept at this temperature for 4-5 hours, the reaction system is cooled to room temperature, filtered, the filter cake is washed twice with acetone and then transferred to a drying oven at a temperature of 55-65℃ and dried to constant weight to obtain ACM-g-MAH.

[0014] Furthermore, the preparation method of composite metal salt particles is as follows: ammonium octamolate powder and deionized water are mixed and stirred, the reaction system is heated to 60-70℃, and metal salt solution and alkaline solution are added dropwise to the reaction system simultaneously. During the dropwise addition, the pH of the system is controlled at 9.8-10.6. After the dropwise addition is completed, the reaction system is heated to 80-90℃ and kept at this temperature for crystallization for 6-8 hours. After post-treatment, composite metal salt particles are obtained.

[0015] Furthermore, the ratio of the ammonium octamolate powder, deionized water, and metal salt solution is 1g:20mL:40-50mL. The metal salt solution is composed of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and deionized water in a ratio of 2g:1g:8-9mL. The alkaline solution is composed of sodium hydroxide, sodium carbonate, and deionized water in a ratio of 2.5g:1g:20mL. The post-treatment includes: after the reaction is complete, the reaction system is cooled to room temperature, filtered, the filter cake is washed with purified water until no nitrate ions are detected, the filter cake is transferred to a drying oven at a temperature of 80-90℃, pulverized, and passed through a 150-mesh sieve to obtain composite metal salt particles.

[0016] Furthermore, the core-shell packing is obtained by the following steps:

[0017] B1. Mix the composite metal salt particles, KH-570, and anhydrous ethanol, ultrasonically disperse for 60-80 min, stir, heat the reaction system to 50-60℃, add sodium hydroxide aqueous solution to the reaction system, keep the reaction at the temperature for 40-50 min, and then perform post-treatment to obtain activated nanoparticles.

[0018] B2. Mix and stir the activated nanoparticles, shell solution and emulsion. Heat the reaction system to 70-80℃. Add the initiator solution dropwise to the reaction system. After the addition is complete, keep the reaction at the temperature for 3-5 hours. Then, perform post-processing to obtain the core-shell filler.

[0019] Further, in step B1, the ratio of the composite metal salt particles, KH-570, anhydrous ethanol, and sodium hydroxide aqueous solution is 3-4g:1g:30mL:5mL, and the concentration of the sodium hydroxide aqueous solution is 1-2mol / L. The post-treatment includes: after the reaction is complete, the reaction system is cooled to room temperature, filtered, the filter cake is washed with purified water until neutral, dried, and the filter cake is transferred to a drying oven at a temperature of 65-75℃ and dried to constant weight to obtain activated nanoparticles.

[0020] Further, in step B2, the ratio of activated nanoparticles, shell solution, emulsion, and initiator solution is 6g:4-5g:50mL:5mL. The shell solution is composed of octavinyl-POSS, methyl methacrylate, and glycidyl methacrylate in a weight ratio of 2:2:1. The emulsion is composed of sodium dodecylbenzenesulfonate, OP-10, N,N-dimethylformamide, and deionized water in a ratio of 3g:2g:30mL:100mL. The initiator solution is composed of potassium persulfate and deionized water in a ratio of 1g:15mL. The post-treatment includes: after the reaction is complete, the reaction system is cooled to room temperature, 10wt% calcium chloride aqueous solution is added to the reaction system to demulsify and precipitate, filtered, the filter cake is washed three times with deionized water and then transferred to a drying oven at a temperature of 70-80℃ and dried to constant weight to obtain the core-shell packing material.

[0021] The present invention also proposes a method for preparing flame-retardant and impact-resistant CPVC power pipe material, wherein CPVC, ACM-g-MAH, core-shell filler and additives are added to a twin-screw extruder, melt-mixed for 3-5 minutes, extruded through a die, and cooled to form, thereby obtaining flame-retardant and impact-resistant CPVC power pipe material.

[0022] Furthermore, the additives consist of antioxidant, dispersant, heat stabilizer, and lubricant in a weight ratio of 5:2:2:1. The antioxidant is antioxidant 1010, the dispersant is stearate, the heat stabilizer is organotin stabilizer, and the lubricant is ethylene bisoleamide. The temperatures of the five temperature zones of the twin-screw extruder are 165°C, 175°C, 175°C, 175°C, and 180°C, respectively, and the die temperature is 185°C.

[0023] The present invention has the following beneficial effects:

[0024] 1. This invention uses CPVC as the matrix, ACM-g-MAH as the toughening agent, and a multiphase synergistic effect of core-shell fillers. ACM-g-MAH imparts toughness to the system while enhancing the interfacial bonding between the matrix and the filler, avoiding excessive damage to heat resistance caused by soft phase coarsening. Methyl methacrylate and octavinyl-POSS in the outer layer of the core-shell filler provide strong rigidity and interfacial constraint effect. Glycidyl methacrylate introduces epoxy groups into the shell layer, increases the degree of crosslinking between components, restricts chain segment movement, and improves the material's resistance to softening under heat. Thus, while improving flame retardancy and impact resistance, it maintains a high Vicat softening temperature.

[0025] 2. This invention also introduces molybdenum-containing composite metal salt particles into the CPVC continuous phase and further constructs a core-shell filler system containing octavinyl-POSS, which can significantly improve the flame retardant and smoke suppression properties of the material. CPVC itself has a high chlorine content, which endows the system with good intrinsic flame retardancy. The Mg and Al components in the composite metal salt particles can absorb and buffer the HCl released during heating, inhibiting the autocatalytic degradation of the matrix, while the molybdenum components can promote the further cross-linking of the pyrolysis residue structure into char, reducing the generation of combustible volatiles and smoke particle precursors. At the same time, the octavinyl-POSS in the shell layer is conducive to the formation of a silicon-rich dense shielding layer during combustion, which works in conjunction with the molybdenum-based char-promoting effect to further enhance the integrity and stability of the char layer, enabling the material to obtain a high oxygen index while reducing the amount of smoke generated.

[0026] 3. This invention also modifies acrylate rubber by grafting maleic anhydride to obtain ACM-g-MAH. The flexible segments of acrylate rubber can induce crazing, shear yielding, and crack tip passivation under external force, thereby absorbing impact energy. After grafting with maleic anhydride, the acrylate rubber changes from a common toughening phase to a reactive toughening phase with polar reactive sites, which can enhance its interfacial adhesion with the CPVC matrix and core-shell filler. At the same time, the shell composed of KH-570, methyl methacrylate, glycidyl methacrylate, and octavinyl-POSS effectively improves the dispersibility of composite metal salt particles, reduces the risk of stress concentration and interfacial debonding caused by direct exposure of inorganic particles, and can effectively introduce inorganic particles into the flame-retardant system, significantly improving the impact resistance of the material. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] In this application, the CAS number for octavinyl-POSS is 69655-76-1;

[0029] In this application, the particle size of the ammonium octamolybdate powder is 20-50 nm, and the Mo content is not less than 60.0%;

[0030] In this application, the acrylate rubber is selected from commercially available products of Jiangsu Bosite Chemical Technology Co., Ltd., with CAS number 67254-76-6, and its appearance is a solid powder with a particle size of 10-100μm;

[0031] In this application, KH-570 is γ-methacryloyloxypropyltrimethoxysilane, CAS number 2530-85-0;

[0032] In this application, CPVC is an acrylic rubber with a chlorine content of 61.0-65.0% and a viscosity (flow time through a Ford cup 4) of 14.0-20.0 s.

[0033] Example 1

[0034] This embodiment provides a method for preparing flame-retardant and impact-resistant CPVC power pipe material, including the following steps:

[0035] Step S1: Preparation of ACM-g-MAH

[0036] Maleic anhydride, dicumyl peroxide, triallyl isocyanurate, antioxidant 1010 and acetone were mixed evenly at a ratio of 30g:4g:2g:1g:60mL to obtain the modified solution.

[0037] Weigh 1 kg of acrylic rubber and add it to a drum dryer. Raise the temperature of the drum dryer to 60°C and set the speed of the drum dryer to 20 r / min. Spray 100 mL of the modifying liquid into the drum dryer. After spraying, dry to remove the solvent and obtain the premix.

[0038] The premixed material was added to a twin-screw extruder. The temperatures of the five temperature zones of the twin-screw extruder were set to 160℃, 165℃, 165℃, 165℃, and 170℃ respectively, and the die temperature was set to 170℃. After melting and mixing for 3 minutes, the material was extruded, cooled, pelletized, and pulverized to obtain crude ACM-g-MAH with a particle size of 0.1-0.5mm.

[0039] The crude ACM-g-MAH product and acetone were added to a reaction flask at a solid-liquid ratio of 1:3 and stirred. The reaction flask was heated to reflux and kept at this temperature for 4 hours. The reaction flask was then cooled to room temperature and filtered. The filter cake was washed twice with acetone and then transferred to a drying oven at 55°C and dried to constant weight to obtain ACM-g-MAH.

[0040] Step S2: Preparation of composite metal salt particles

[0041] Magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and deionized water were mixed evenly at a ratio of 2g:1g:8mL to obtain a metal salt solution.

[0042] Sodium hydroxide, sodium carbonate, and deionized water were mixed evenly at a ratio of 2.5g:1g:20mL to obtain an alkaline solution.

[0043] Weigh out 50g of ammonium octamolate powder and 1000mL of deionized water and add them to the reaction flask. Stir the mixture and heat the reaction flask to 60℃. Simultaneously add 2L of metal salt solution and alkali solution to the reaction flask. During the addition, adjust the dropping rate of the alkali solution and control the pH of the system to 9.8. After the addition is complete, heat the reaction flask to 80℃ and keep it at this temperature for crystallization for 6 hours. Cool the reaction flask to room temperature, filter it, and wash the filter cake with purified water until no nitrate ions are detected. Transfer the filter cake to a drying oven at 80℃, crush it, and pass it through a 150-mesh sieve to obtain composite metal salt particles.

[0044] Step S3: Preparation of core-shell packing material

[0045] Weigh out 60g of composite metal salt particles, 20g of KH-570, and 600mL of anhydrous ethanol and add them to a reaction flask. Mix and ultrasonically disperse for 60min. Fix the reaction flask on an iron stand with mechanical stirring and stir. Heat the reaction flask to 50℃ and add 100mL of 1mol / L sodium hydroxide aqueous solution to the reaction flask. Keep the reaction at this temperature for 40min. Cool the reaction flask to room temperature and filter. Wash the filter cake with purified water until neutral and then dry it. Transfer the filter cake to a drying oven at 65℃ and dry it to constant weight to obtain activated nanoparticles.

[0046] Octadecyl-POSS, methyl methacrylate, and glycidyl methacrylate were mixed evenly in a weight ratio of 2:2:1 to obtain a shell solution.

[0047] Sodium dodecylbenzenesulfonate, OP-10, N,N-dimethylformamide and deionized water were mixed evenly at a ratio of 3g:2g:30mL:100mL to obtain an emulsion.

[0048] Potassium persulfate and deionized water were mixed evenly at a ratio of 1g:15mL to obtain an initiator solution;

[0049] Weigh out 60g of activated nanoparticles, 40g of shell solution, and 500mL of emulsion and add them to a reaction flask. Stir the mixture and heat the reaction flask to 70℃. Add 50mL of initiator solution dropwise to the reaction flask. After the addition is complete, keep the reaction flask at this temperature for 3 hours. Cool the reaction flask to room temperature and add 500mL of 10wt% calcium chloride aqueous solution to break the emulsion and precipitate the product. Filter the product and wash the filter cake three times with deionized water. Transfer the cake to a drying oven at 70℃ and dry it to constant weight to obtain the core-shell packing material.

[0050] Step S4: Preparation of flame-retardant and impact-resistant CPVC power pipe material

[0051] Antioxidant 1010, calcium stearate, organotin stabilizer and ethylene dioleamide were mixed evenly in a weight ratio of 5:2:2:1 to obtain the additive.

[0052] Weigh out the following components by weight: 70 parts CPVC, 8 parts ACM-g-MAH, 9 parts core-shell filler, and 3 parts additives. Add these to a twin-screw extruder. Set the temperatures of the five temperature zones of the twin-screw extruder to 165℃, 175℃, 175℃, 175℃, and 180℃ respectively. Set the die temperature to 185℃. Melt and mix for 3 minutes. After extrusion through the die, cool and shape to obtain flame-retardant and impact-resistant CPVC power pipe material.

[0053] Example 2

[0054] This embodiment provides a method for preparing flame-retardant and impact-resistant CPVC power pipe material, including the following steps:

[0055] Step S1: Preparation of ACM-g-MAH

[0056] Maleic anhydride, dicumyl peroxide, triallyl isocyanurate, antioxidant 1010 and acetone were mixed evenly at a ratio of 30g:4g:2g:1g:60mL to obtain the modified solution.

[0057] Weigh 1 kg of acrylic rubber and add it to a drum dryer. Raise the temperature of the drum dryer to 65°C and set the speed of the drum dryer to 35 r / min. Spray 100 mL of the modifying liquid into the drum dryer. After spraying, dry to remove the solvent and obtain the premix.

[0058] The premixed material was added to a twin-screw extruder. The temperatures of the five temperature zones of the twin-screw extruder were set to 160℃, 165℃, 165℃, 165℃, and 170℃ respectively, and the die temperature was set to 170℃. After melting and mixing for 4 minutes, the material was extruded, cooled, pelletized, and pulverized to obtain crude ACM-g-MAH with a particle size of 0.1-0.5mm.

[0059] The crude ACM-g-MAH product and acetone were added to a reaction flask at a solid-liquid ratio of 1:4 and stirred. The reaction flask was heated to reflux and kept at this temperature for 4.5 h. The reaction flask was then cooled to room temperature and filtered. The filter cake was washed twice with acetone and then transferred to a drying oven at 60 °C and dried to constant weight to obtain ACM-g-MAH.

[0060] In the reaction, maleic anhydride, dicumyl peroxide, triallyl isocyanurate, and antioxidant 1010 are uniformly dispersed in acrylate rubber particles through solution spraying and rotary drying. Then, under the heating conditions of a twin-screw extruder, dicumyl peroxide is used as a free radical initiator for free radical polymerization, which introduces maleic anhydride into the ACM molecular chain as a side group. Triallyl isocyanurate acts as a free radical reaction accelerator and co-reactant during the reaction, improving grafting efficiency and inhibiting excessive molecular weight reduction caused by simple chain breakage. Antioxidant 1010 inhibits thermo-oxidative degradation during processing and avoids aging of the ACM backbone. Subsequently, the crude product is subjected to acetone reflux extraction and washing to remove ungrafted maleic anhydride, small molecule byproducts, and residual additives, thereby obtaining a relatively pure ACM-g-MAH. After grafting with maleic anhydride, polar groups are introduced into the ACM molecular chain, transforming it from a common elastomer toughening phase into a reactive toughening phase with polar reactive sites. The flexible segments of ACM can still induce crimping, shear yielding, and crack tip passivation under external impact, thereby absorbing and dissipating impact energy. The polar groups of ACM-g-MAH enhance the interfacial adhesion between ACM and the CPVC continuous phase and the subsequent core-shell filler shell layer, making the dispersed phase more refined and the interface more stable, less prone to debonding and stress concentration, and improving the notched impact strength. At the same time, due to the enhanced interfacial effect, the coarsening phenomenon of the soft phase is suppressed, reducing the negative impact of ordinary toughening agents on the heat resistance of the material. It helps to maintain a high Vicat softening temperature while improving toughness. The more uniform interface is also conducive to the effective dispersion of flame retardant components in the matrix, thereby improving flame retardant and smoke suppression performance.

[0061] Step S2: Preparation of composite metal salt particles

[0062] Magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and deionized water were mixed evenly at a ratio of 2g:1g:8.5mL to obtain a metal salt solution.

[0063] Sodium hydroxide, sodium carbonate, and deionized water were mixed evenly at a ratio of 2.5g:1g:20mL to obtain an alkaline solution.

[0064] Weigh out 50g of ammonium octamolate powder and 1000mL of deionized water and add them to a reaction flask. Stir the mixture and heat the reaction flask to 65℃. Simultaneously add 2.3L of metal salt solution and alkali solution to the reaction flask. During the addition, adjust the dropping rate of the alkali solution and control the pH of the system to 10.2. After the addition is complete, heat the reaction flask to 85℃ and keep it at this temperature for crystallization for 7 hours. Cool the reaction flask to room temperature, filter the mixture, and wash the filter cake with purified water until no nitrate ions are detected. Transfer the filter cake to a drying oven at 85℃, pulverize it, and pass it through a 150-mesh sieve to obtain composite metal salt particles.

[0065] In the reaction, ammonium octamolate is dispersed in water, and magnesium nitrate and aluminum nitrate are used to provide Mg, respectively. 2+ And Al 3+ In the alkaline environment provided by NaOH and Na2CO3, Mg and Al precipitate with ammonium octamolate as nucleation sites, forming a relatively stable precipitate structure and particle composition. Subsequent heat preservation and crystallization help the precipitate particles to further mature, regularize, and stabilize. CPVC is prone to deHCl reaction during heating, and the released HCl further promotes CPVC degradation, forming an autocatalytic process. The Mg and Al components in the composite metal salt particles can absorb, buffer, or neutralize some HCl during heating, thereby reducing the acidity of the system, slowing down the rate of further dehydrochlorination and chain degradation of CPVC, and improving thermal stability. The molybdenum components mainly play a role in promoting charring and suppressing smoke. During combustion or thermal pyrolysis, the molybdenum components are conducive to promoting further cross-linking, aromatization, and charring of the pyrolysis residue structure, reducing the generation of low-molecular-weight combustible volatiles and smoke particle precursors, and improving the oxygen index and smoke suppression performance of the material.

[0066] Step S3: Preparation of core-shell packing material

[0067] Weigh out 70g of composite metal salt particles, 20g of KH-570, and 600mL of anhydrous ethanol and add them to a reaction flask. Mix and sonicate for 70min. Fix the reaction flask on an iron stand with mechanical stirring and stir. Heat the reaction flask to 55℃ and add 100mL of 1.5mol / L sodium hydroxide aqueous solution. Keep the reaction at this temperature for 45min. Cool the reaction flask to room temperature and filter. Wash the filter cake with purified water until neutral and then dry it. Transfer the filter cake to a drying oven at 70℃ and dry it to constant weight to obtain activated nanoparticles.

[0068] Octadecyl-POSS, methyl methacrylate, and glycidyl methacrylate were mixed evenly in a weight ratio of 2:2:1 to obtain a shell solution.

[0069] Sodium dodecylbenzenesulfonate, OP-10, N,N-dimethylformamide and deionized water were mixed evenly at a ratio of 3g:2g:30mL:100mL to obtain an emulsion.

[0070] Potassium persulfate and deionized water were mixed evenly at a ratio of 1g:15mL to obtain an initiator solution;

[0071] Weigh out 60g of activated nanoparticles, 45g of shell solution, and 500mL of emulsion and add them to a reaction flask. Stir the mixture and heat the reaction flask to 75℃. Add 50mL of initiator solution dropwise to the reaction flask. After the addition is complete, keep the reaction at this temperature for 3.5h. Cool the reaction flask to room temperature and add 500mL of 10wt% calcium chloride aqueous solution to the reaction flask to break the emulsion and precipitate the product. Filter the product and wash the filter cake three times with deionized water. Transfer the filter cake to a drying oven at 75℃ and dry it to constant weight to obtain the core-shell packing material.

[0072] In the reaction, KH-570 is used as a surfactant to activate the surface of the composite metal salt particles, modifying the surface of the composite metal salt particles with unsaturated olefin double bonds. Then, in the emulsion system, potassium persulfate is decomposed by heat to generate free radicals, which initiate the free radical polymerization of methyl methacrylate and glycidyl methacrylate, depositing a coating on the particle surface. Octadecyl-POSS, due to the presence of multiple vinyl groups in its molecule, can also participate in the free radical polymerization and embed itself in the coating layer, thus forming a core-shell filler with the composite metal salt as the core and the methyl methacrylate, glycidyl methacrylate, and octavincyl-POSS polymer layer as the outer shell. In the shell layer, methyl methacrylate provides rigidity and interfacial characteristics that are well matched with organic resins, while glycidyl methacrylate introduces epoxy groups, increasing the polarity of the shell layer and enhancing the interfacial interaction with CPVC and acrylate rubber-g-MAH. Octadecyl-POSS provides a cage-like rigid structure and silicon-rich carbonization characteristics, giving the shell layer both heat resistance and flame retardant shielding functions. After activation with KH-570 and coating with an organic shell, the filler surface changes from a rigid inorganic interface to an interface with certain organic phase transition characteristics. This significantly improves the dispersibility and compatibility of the filler in the CPVC and acrylate rubber-g-MAH system, reduces the risk of interface debonding, and alleviates stress concentration caused by direct exposure of inorganic particles. Thus, while introducing an inorganic flame-retardant phase, it still maintains a high notched impact strength. Methyl methacrylate and POSS in the shell have strong rigidity, and the polar epoxy groups introduced by glycidyl methacrylate improve the bonding between the shell and the matrix, restricting the movement of polymer chain segments under heated conditions. This allows the core-shell filler to truly play a rigid constraint role, maintaining a high Vicat softening temperature of the material. The core-shell filler enables molybdenum-containing composite metal salt particles to be more uniformly dispersed in the CPVC continuous phase, improving the utilization efficiency of the flame-retardant components. At the same time, POSS is conducive to forming a silicon-rich dense shielding layer during combustion. This, combined with the char-promoting effect of the molybdenum system, enhances the integrity and stability of the char layer, blocks the transfer of heat and combustible volatiles, and has a significant effect on improving the oxygen index and smoke suppression performance.

[0073] Step S4: Preparation of flame-retardant and impact-resistant CPVC power pipe material

[0074] Antioxidant 1010, zinc stearate, organotin stabilizer, and ethylene dioleamide were mixed evenly in a weight ratio of 5:2:2:1 to obtain the additive.

[0075] Weigh out the following components by weight: 75 parts CPVC, 9 parts ACM-g-MAH, 10 parts core-shell filler, and 4 parts additives. Add these to a twin-screw extruder. Set the temperatures of the five temperature zones of the twin-screw extruder to 165℃, 175℃, 175℃, 175℃, and 180℃, respectively. Set the die temperature to 185℃. Melt and mix for 4 minutes. After extrusion through the die, cool and shape to obtain flame-retardant and impact-resistant CPVC power pipe material.

[0076] Example 3

[0077] This embodiment provides a method for preparing flame-retardant and impact-resistant CPVC power pipe material, including the following steps:

[0078] Step S1: Preparation of ACM-g-MAH

[0079] Maleic anhydride, dicumyl peroxide, triallyl isocyanurate, antioxidant 1010 and acetone were mixed evenly at a ratio of 30g:4g:2g:1g:60mL to obtain the modified solution.

[0080] Weigh 1 kg of acrylic rubber and add it to a drum dryer. Raise the temperature of the drum dryer to 70°C and set the speed of the drum dryer to 50 r / min. Spray 100 mL of the modifying liquid into the drum dryer. After spraying, dry to remove the solvent and obtain the premix.

[0081] The premixed material was added to a twin-screw extruder. The temperatures of the five temperature zones of the twin-screw extruder were set to 160℃, 165℃, 165℃, 165℃ and 170℃ respectively, and the die temperature was set to 170℃. After melting and mixing for 5 minutes, the material was extruded, cooled, pelletized and crushed to obtain crude ACM-g-MAH with a particle size of 0.1-0.5mm.

[0082] The crude ACM-g-MAH product and acetone were added to a reaction flask at a solid-liquid ratio of 1:5 and stirred. The reaction flask was heated to reflux and kept at this temperature for 5 hours. The reaction flask was then cooled to room temperature and filtered. The filter cake was washed twice with acetone and then transferred to a drying oven at 65°C and dried to constant weight to obtain ACM-g-MAH.

[0083] Step S2: Preparation of composite metal salt particles

[0084] Magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and deionized water were mixed evenly at a ratio of 2g:1g:9mL to obtain a metal salt solution.

[0085] Sodium hydroxide, sodium carbonate, and deionized water were mixed evenly at a ratio of 2.5g:1g:20mL to obtain an alkaline solution.

[0086] Weigh out 50g of ammonium octamolate powder and 1000mL of deionized water and add them to the reaction flask. Stir the mixture and heat the reaction flask to 70℃. Simultaneously add 2.5L of metal salt solution and alkali solution to the reaction flask. During the addition, adjust the dropping rate of the alkali solution and control the pH of the system to 10.6. After the addition is complete, heat the reaction flask to 90℃ and keep it at that temperature for crystallization for 8 hours. Cool the reaction flask to room temperature, filter it, and wash the filter cake with purified water until no nitrate ions are detected. Transfer the filter cake to a drying oven at 90℃, crush it, and pass it through a 150-mesh sieve to obtain composite metal salt particles.

[0087] Step S3: Preparation of core-shell packing material

[0088] Weigh out 80g of composite metal salt particles, 20g of KH-570, and 600mL of anhydrous ethanol and add them to a reaction flask. Mix and ultrasonically disperse for 80min. Fix the reaction flask on an iron stand with mechanical stirring and stir. Heat the reaction flask to 60℃ and add 100mL of 2mol / L sodium hydroxide aqueous solution. Keep the reaction at this temperature for 50min. Cool the reaction flask to room temperature and filter. Wash the filter cake with purified water until neutral and then dry it. Transfer the filter cake to a drying oven at 75℃ and dry it to constant weight to obtain activated nanoparticles.

[0089] Octadecyl-POSS, methyl methacrylate, and glycidyl methacrylate were mixed evenly in a weight ratio of 2:2:1 to obtain a shell solution.

[0090] Sodium dodecylbenzenesulfonate, OP-10, N,N-dimethylformamide and deionized water were mixed evenly at a ratio of 3g:2g:30mL:100mL to obtain an emulsion.

[0091] Potassium persulfate and deionized water were mixed evenly at a ratio of 1g:15mL to obtain an initiator solution;

[0092] Weigh out 60g of activated nanoparticles, 50g of shell solution, and 500mL of emulsion and add them to a reaction flask. Stir the mixture and heat the reaction flask to 80℃. Add 50mL of initiator solution dropwise to the reaction flask. After the addition is complete, keep the reaction flask at this temperature for 3-5 hours. Cool the reaction flask to room temperature and add 500mL of 10wt% calcium chloride aqueous solution to break the emulsion and precipitate the product. Filter the product and wash the filter cake three times with deionized water. Transfer the cake to a drying oven at 80℃ and dry it to constant weight to obtain the core-shell packing material.

[0093] Step S4: Preparation of flame-retardant and impact-resistant CPVC power pipe material

[0094] Antioxidant 1010, barium stearate, organotin stabilizer, and ethylene dioleamide were mixed evenly in a weight ratio of 5:2:2:1 to obtain the additive.

[0095] Weigh out the following components by weight: 80 parts CPVC, 10 parts ACM-g-MAH, 11 parts core-shell filler, and 5 parts additives. Add these to a twin-screw extruder. Set the temperatures of the five temperature zones of the twin-screw extruder to 165℃, 175℃, 175℃, 175℃, and 180℃ respectively. Set the die temperature to 185℃. Melt and mix for 5 minutes. After extrusion through the die, cool and shape to obtain flame-retardant and impact-resistant CPVC power pipe material.

[0096] Comparative Example 1

[0097] The difference between this comparative example and Example 3 is that step S1 is omitted, and the acrylate rubber in step S1 is used instead of ACM-g-MAH in step S4.

[0098] Comparative Example 2

[0099] The difference between this comparative example and Example 3 is that the composite metal salt particles in step S2 are used instead of the core-shell filler in step S4.

[0100] Comparative Example 3

[0101] The difference between this comparative example and Example 3 is that the activated nanoparticles in step S3 replace the core-shell filler in step S4.

[0102] Comparative Example 4

[0103] The difference between this comparative example and Example 3 is that octavinyl-POSS was not added to the shell solution.

[0104] Performance testing:

[0105] The oxygen index of the flame-retardant and impact-resistant CPVC power pipe material samples prepared in Examples 1-3 and Comparative Examples 1-4 was determined according to the standard GB / T 2406.2-2009 "Determination of flammability of plastics by oxygen index method - Part 2: Room temperature test".

[0106] The notched impact strength of the flame-retardant and impact-resistant CPVC power pipe material samples prepared in Examples 1-3 and Comparative Examples 1-4 was determined in accordance with the standard GB / T 1843-2008 "Determination of Impact Strength of Plastic Cantilever Beams".

[0107] The specific optical density D of the smoke produced during combustion of the flame-retardant and impact-resistant CPVC power pipe material samples prepared in Examples 1-3 and Comparative Examples 1-4 was determined according to standard GB / T 8323.2-2008 "Plastics Smoke Generation Part 2: Test Method for Determination of Smoke Density by Single Chamber Method". s10 ;

[0108] Refer to standard GB / T 1633-2000 "Determination of Vicat Softening Temperature (VST) of Thermoplastic Plastics" in section B. 50 The Vicat softening temperature of the flame-retardant and impact-resistant CPVC power pipe material samples prepared in Examples 1-3 and Comparative Examples 1-4 was determined by a method. The specific test data are shown in Table 1 below.

[0109] Table 1 - Performance Test Data of Samples

[0110]

[0111] Data Analysis:

[0112] The flame-retardant and impact-resistant CPVC power pipe material prepared by this invention has an oxygen index of 63.2-66.1% and a notched impact strength of 20.3-21.4 kJ / m. 2 , compared to optical density D s10 The results showed that the oxygen index, notched impact strength, and Vicat softening temperature of the CPVC power pipe material reached 100-102℃, and the Vicat softening temperature reached 115.5-118.6℃. All performance test data were superior to those of the comparative example. This indicates that the present invention first obtains a reactive ACM-g-MAH toughening agent by grafting maleic anhydride onto acrylate rubber. Then, using Mg / Al / molybdenum composite metal salt particles as the core, and after activation with KH-570, a core-shell filler is constructed by combining methyl methacrylate, glycidyl methacrylate, and octavinyl-POSS to reinforce the CPVC main resin. This not only effectively improves the oxygen index, notched impact strength, and Vicat softening temperature of the flame-retardant and impact-resistant CPVC power pipe material, but also reduces the smoke density of the material.

[0113] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A flame-retardant and impact-resistant CPVC power pipe material, characterized in that, It includes the following components by weight: 70-80 parts CPVC, 8-10 parts ACM-g-MAH, 9-11 parts core-shell filler, and 3-5 parts additives; The ACM-g-MAH is an acrylic rubber modified with maleic anhydride; The core layer of the core-shell filler is a composite metal salt particle containing molybdenum, magnesium and aluminum. The shell layer is obtained by surface modification of the composite metal salt particle with KH-570, followed by emulsification polymerization using octavinyl-POSS, methyl methacrylate and glycidyl methacrylate as the shell solution.

2. The flame-retardant and impact-resistant CPVC power pipe material according to claim 1, characterized in that, ACM-g-MAH is obtained through the following steps: A1. Add acrylic rubber to a drum dryer, raise the temperature of the drum dryer to 60-70℃, spray the finishing liquid into the drum dryer, and after spraying, dry to remove the solvent to obtain the premix. A2. Add the premixed material to a twin-screw extruder, melt mix for 3-5 minutes, then extrude. After cooling, pelletizing, and crushing, obtain crude ACM-g-MAH. Extract the crude ACM-g-MAH to obtain ACM-g-MAH.

3. The flame-retardant and impact-resistant CPVC power pipe material according to claim 2, characterized in that, In step A1, the solid-liquid ratio of the acrylate rubber and the modifying liquid is 10:

1. The modifying liquid is composed of maleic anhydride, dicumyl peroxide, triallyl isocyanurate, antioxidant 1010, and acetone in a ratio of 30g:4g:2g:1g:60mL. The particle size of the acrylate rubber is 10-100μm, and the rotation speed of the drum dryer is 20-50r / min. In step A2, the temperatures of the five temperature zones of the twin-screw extruder are 160℃, 165℃, 165℃, 165℃, and 170℃, respectively, and the die temperature is 170℃. The particle size of the crude ACM-g-MAH product is 0.1-0.5mm.

4. The flame-retardant and impact-resistant CPVC power pipe material according to claim 2, characterized in that, The extraction operation is as follows: crude ACM-g-MAH is mixed with acetone at a solid-liquid ratio of 1:3-5. The reaction system is heated to reflux and kept at this temperature for 4-5 hours. The reaction system is then cooled to room temperature and filtered. The filter cake is washed twice with acetone and then transferred to a drying oven at 55-65℃ and dried to constant weight to obtain ACM-g-MAH.

5. The flame-retardant and impact-resistant CPVC power pipe material according to claim 1, characterized in that, The preparation method of composite metal salt particles is as follows: Ammonium octamolate powder and deionized water are mixed and stirred, the reaction system is heated to 60-70℃, and metal salt solution and alkaline solution are added dropwise to the reaction system simultaneously. During the dropwise addition, the pH of the system is controlled at 9.8-10.

6. After the dropwise addition is completed, the reaction system is heated to 80-90℃ and kept at this temperature for crystallization for 6-8 hours. After post-treatment, composite metal salt particles are obtained.

6. The flame-retardant and impact-resistant CPVC power pipe material according to claim 5, characterized in that, The ratio of ammonium octamolate powder, deionized water, and metal salt solution is 1g:20mL:40-50mL. The metal salt solution is composed of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and deionized water in a ratio of 2g:1g:8-9mL. The alkaline solution is composed of sodium hydroxide, sodium carbonate, and deionized water in a ratio of 2.5g:1g:20mL. The post-treatment includes: after the reaction is complete, the reaction system is cooled to room temperature, filtered, the filter cake is washed with purified water until no nitrate is detected, the filter cake is transferred to a drying oven at 80-90℃, pulverized, and passed through a 150-mesh sieve to obtain composite metal salt particles.

7. The flame-retardant and impact-resistant CPVC power pipe material according to claim 1, characterized in that, The core-shell packing material is obtained by the following steps: B1. Mix the composite metal salt particles, KH-570, and anhydrous ethanol, ultrasonically disperse for 60-80 min, stir, heat the reaction system to 50-60℃, add sodium hydroxide aqueous solution to the reaction system, keep the reaction at the temperature for 40-50 min, and then perform post-treatment to obtain activated nanoparticles. B2. Mix and stir the activated nanoparticles, shell solution and emulsion. Heat the reaction system to 70-80℃. Add the initiator solution dropwise to the reaction system. After the addition is complete, keep the reaction at the temperature for 3-5 hours. Then, perform post-processing to obtain the core-shell filler.

8. The flame-retardant and impact-resistant CPVC power pipe material according to claim 7, characterized in that, In step B1, the ratio of the composite metal salt particles, KH-570, anhydrous ethanol, and sodium hydroxide aqueous solution is 3-4 g:1 g:30 mL:5 mL, and the concentration of the sodium hydroxide aqueous solution is 1-2 mol / L. The post-treatment includes: after the reaction is complete, cooling the reaction system to room temperature, filtering, washing the filter cake with purified water until neutral, drying it, transferring the filter cake to a drying oven at 65-75℃, and drying it to constant weight to obtain activated nanoparticles; in step B2, the ratio of the activated nanoparticles, shell solution, emulsion, and initiator solution is 6 g:4-5 g:50 mL:5 mL, and the shell solution is composed of octavinyl... -POSS, methyl methacrylate, and glycidyl methacrylate are composed in a weight ratio of 2:2:

1. The emulsion is composed of sodium dodecylbenzenesulfonate, OP-10, N,N-dimethylformamide, and deionized water in a ratio of 3g:2g:30mL:100mL. The initiator solution is composed of potassium persulfate and deionized water in a ratio of 1g:15mL. The post-treatment includes: after the reaction is completed, the reaction system is cooled to room temperature, 10wt% calcium chloride aqueous solution is added to the reaction system to demulsify and precipitate, filtered, the filter cake is washed 3 times with deionized water and then transferred to a drying oven at a temperature of 70-80℃ and dried to constant weight to obtain the core-shell packing.

9. A method for preparing a flame-retardant and impact-resistant CPVC power pipe material as described in any one of claims 1-8, characterized in that, CPVC, ACM-g-MAH, core-shell filler, and additives are added to a twin-screw extruder and melt-mixed for 3-5 minutes. After extrusion through a die, the mixture is cooled and shaped to obtain flame-retardant and impact-resistant CPVC power pipe material.

10. The method for preparing a flame-retardant and impact-resistant CPVC power pipe material according to claim 9, characterized in that, The additives consist of antioxidant, dispersant, heat stabilizer, and lubricant in a weight ratio of 5:2:2:

1. The antioxidant is antioxidant 1010, the dispersant is stearate, the heat stabilizer is organotin stabilizer, and the lubricant is ethylene bisoleamide. The temperatures of the five temperature zones of the twin-screw extruder are 165°C, 175°C, 175°C, 175°C, and 180°C, respectively, and the die temperature is 185°C.

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