Perspective durable antistatic filter tip rod conveying pipeline composite material and preparation method thereof

Abstract

The invention relates to the technical field of polymer composite materials, in particular to a perspective durable antistatic filter tip rod conveying pipeline composite material and a preparation method thereof. Comprising a fluororesin base material, antimony-doped tin dioxide, polyaniline, an epoxy-acetal double-effect amine capturing copolymer, a sulfonated amino macrogol ester doped stable copolymer, polyethyleneimine modified nano-hydroxyapatite, polytetrafluoroethylene micro powder, a titanate coupling agent and a hindered phenol antioxidant. By means of the epoxy-acetal double-effect amine capturing copolymer, the sulfonated amino macrogol ester doped stable copolymer and the polyethyleneimine modified nano-hydroxyapatite, the problem that volatile nitrogen-containing components in tobacco and filter rods are continuously released and enriched in a closed conveying pipeline, and consequently the conductive function of polyaniline loses efficacy is solved.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, specifically a transparent, durable antistatic filter rod delivery pipe composite material and its preparation method. Background Technology

[0002] In cigarette production, high-speed filter rod conveying pipelines continuously transport filter rods from the storage silo to the forming station. During this process, the high-speed friction between the filter rods and the inner wall of the pipeline continuously generates static electricity. If this static electricity cannot be effectively discharged, it can cause blockages or even damage to the filter rod ends, severely impacting production efficiency and product quality. Simultaneously, to enable online visual inspection of abnormalities such as blockages, damage, and foreign matter contamination, the pipeline must also possess good optical transparency. Fluoropolymers such as perfluoroalkoxy resins (PFA) and tetrafluoroethylene-hexafluoropropylene copolymers (FEP) are ideal choices for the pipeline substrate due to their strong chemical inertness, low coefficient of friction, and good transparency; however, since they are insulators, conductive functional components must be introduced.

[0003] Existing transparent antistatic composite materials mainly employ two types of conductive components. One type consists of inorganic nano-conductive powders such as antimony-doped tin dioxide (ATO) and indium tin oxide (ITO), which offer good transparency but exhibit poor dispersibility in low-polarity fluoropolymer substrates. When used alone, they require high addition amounts to achieve antistatic properties, which in turn compromises transparency. The other type comprises intrinsically conductive polymers such as polyaniline (PANI) and polythiophene, which can construct molecular-level conductive networks at extremely low dosages, significantly reducing their impact on transparency compared to inorganic powders. Among these, polyaniline is the preferred organic conductive component due to its mature synthesis process and wide adjustable conductivity range. Combining antimony-doped tin dioxide with polyaniline allows for complementary conductive mechanisms: the inorganic powder provides a stable skeletal conductive pathway, while polyaniline fills the interparticle gaps, optimizing network continuity. This approach simultaneously satisfies both transparency and antistatic requirements at relatively low total addition amounts.

[0004] However, the conductivity of polyaniline depends on the protonated doped state (emerald green imine salt state) of its main chain imine (-NH-) sites. Ammonia and low-molecular-weight volatile aliphatic amines can neutralize the protons in the polyaniline doped state, causing the polyaniline to change from the conductive emerald green imine salt state to the insulating emerald green imine base state, thus reducing its conductivity. Tobacco and filter rods contain ammonia and various low-molecular-weight aliphatic amines (including methylamine, ethylamine, trimethylamine, etc.) derived from the thermal decomposition and degradation of nitrogen-containing components. These substances are continuously released and accumulate in closed delivery pipelines, leading to the failure of polyaniline's conductivity. Currently, there is no specific solution to this failure problem. Summary of the Invention

[0005] (1) Technical problems to be solved The purpose of this invention is to provide a transparent, durable antistatic filter rod delivery pipe composite material and its preparation method, in order to solve the problem that the continuous release and accumulation of volatile nitrogen-containing components in tobacco and filter rods in a closed delivery pipe leads to the failure of the conductive function of polyaniline.

[0006] (2) Technical solution To achieve the above objectives, on the one hand, the present invention provides a transparent, durable antistatic filter rod conveying pipe composite material, comprising the following parts by weight: 82.0~91.0 parts of fluororesin substrate, 3.0~7.0 parts of antimony-doped tin dioxide, 0.5~2.0 parts of polyaniline, 0.5~1.5 parts of epoxy-acetal dual-effect amine-capturing copolymer, 0.5~1.5 parts of sulfonated amino polyethylene glycol ester doped stable copolymer, 0.3~1.0 parts of polyethyleneimine modified nano-hydroxyapatite, 0.5~2.0 parts of polytetrafluoroethylene micro powder, 0.2~0.8 parts of titanate coupling agent, and 0.1~0.5 parts of hindered phenolic antioxidant.

[0007] Furthermore, the preparation method of the epoxy-acetal dual-effect amine-scavenging copolymer includes the following steps: S11. Methacrylic acid, 4-hydroxybutyraldehyde and p-toluenesulfonic acid were dissolved in toluene, hydroquinone methyl ether was added as a polymerization inhibitor, a Dean-Stark water separator was assembled, and the reaction was refluxed at 110°C. Water was removed by azeotropic distillation. After the reaction was completed, the mixture was cooled to room temperature and washed successively with saturated sodium bicarbonate aqueous solution and deionized water. The organic layer was dried with anhydrous magnesium sulfate and filtered. Toluene was removed by vacuum distillation. Hydroquinone methyl ether was added and the mixture was purified by short-path vacuum distillation to obtain intermediate 1. S12. Intermediate 1 and ethylene glycol were dissolved in toluene, p-toluenesulfonic acid was added as an acid catalyst and hydroquinone methyl ether as a polymerization inhibitor, a Dean-Stark water separator was assembled, and the reaction was refluxed at 110°C. Water was removed by azeotropic distillation. After the reaction was completed, the mixture was cooled to room temperature and washed successively with saturated sodium bicarbonate aqueous solution and deionized water. The organic layer was dried with anhydrous magnesium sulfate and filtered. Toluene was removed by vacuum distillation. After adding hydroquinone methyl ether, the mixture was purified by short-path vacuum distillation to obtain intermediate 2. S13. Glycidyl methacrylate, maleic anhydride, and intermediate 2 were dissolved in 1,4-dioxane dried through a 4 Å molecular sieve. Azobisisobutyronitrile was added, and the mixture was placed in an ice-water bath. After purging with high-purity nitrogen to remove oxygen, the temperature was raised to 70°C, and the reaction was carried out under nitrogen protection with magnetic stirring at a constant temperature. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was slowly added dropwise to anhydrous diethyl ether to precipitate. The white solid was collected by filtration. The solid was redissolved in dried 1,4-dioxane and added dropwise to anhydrous diethyl ether to precipitate again. The above recrystallization operation was repeated three times. The final solid was dried under vacuum to obtain an epoxy-acetal bis-amine scavenging copolymer.

[0008] Furthermore, the preparation method of the sulfonated amino polyethylene glycol ester doped stable copolymer includes the following steps: S21. Dissolve aminoethyl acrylate hydrochloride in a mixed solvent of tetrahydrofuran and deionized water, place in an ice-water bath, add triethylamine to neutralize, and then slowly add a tetrahydrofuran solution of di-tert-butyl dicarbonate. After the addition is complete, remove the ice bath and stir the reaction at 25°C. After the reaction is complete, evaporate by rotary evaporation, add deionized water to dilute, extract three times with ethyl acetate, combine the organic phases, wash successively with 5% citric acid aqueous solution and saturated brine, dry the organic layer with anhydrous magnesium sulfate and filter, add hydroquinone methyl ether and evaporate under reduced pressure, then dry under vacuum to obtain intermediate 3; S22. Sodium styrene sulfonate, intermediate 3 and polyethylene glycol methacrylate were dissolved in a mixed solvent of deionized water and ethanol. 4,4'-azobis(4-cyanovaleric acid) was added as a water-soluble free radical initiator. After bubbling with high-purity nitrogen to remove oxygen, the temperature was raised to 65°C and reacted at a constant temperature. After the reaction was completed, the mixture was dialyzed with deionized water. The dialysate was freeze-dried to obtain the copolymer precursor. S23. Dissolve the copolymer precursor in deionized water and pass it through a strong acid cation exchange resin column that has been regenerated with 1 mol / L hydrochloric acid and then thoroughly washed with deionized water until the pH of the eluent is 6-7 at a flow rate of 5 mL / min. Elute with deionized water until the pH of the eluent is stable. Collect all the eluents, combine them, and freeze-dry to obtain the ion-exchange intermediate. S24. Dissolve the ion-exchange intermediate in dichloromethane and place it in an ice-water bath. Slowly add trifluoroacetic acid in a fume hood, remove the ice bath, and stir the reaction at 25°C. Immediately after the reaction is complete, slowly add the solution dropwise to a saturated sodium bicarbonate aqueous solution to neutralize the residual trifluoroacetic acid. After thorough stirring, dialyze with deionized water and freeze-dry the dialysate to obtain a sulfonated amino polyethylene glycol ester doped stable copolymer.

[0009] Furthermore, the preparation method of the polyethyleneimine modified nano-hydroxyapatite is as follows: nano-hydroxyapatite powder is dispersed in deionized water and ultrasonically dispersed to obtain a uniform suspension. Polyethyleneimine is dissolved in deionized water and slowly added dropwise to the above suspension. The mixture is stirred and reacted at 25°C. After the reaction is completed, the precipitate is collected by centrifugation, washed with deionized water, and vacuum dried to obtain polyethyleneimine modified nano-hydroxyapatite.

[0010] Furthermore, the nano-hydroxyapatite has a particle size of 20-50 nm and a specific surface area of ​​not less than 80 m² / g; the polyethyleneimine has a number-average molecular weight of 600 g / mol.

[0011] Further, the fluororesin substrate is one of perfluoroalkoxy resin or tetrafluoroethylene-hexafluoropropylene copolymer; the hindered phenolic antioxidant is pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); and the titanate coupling agent is isopropyltris(dioctylpyrophosphate)titanate.

[0012] On the other hand, the present invention also provides a method for preparing a transparent, durable antistatic filter rod delivery pipe composite material, comprising the following steps: S1. Inorganic component surface treatment: Antimony-doped tin dioxide and titanate coupling agent are added to a high-speed mixer and premixed at 75~85℃ for 25~35min to obtain surface-treated antimony-doped tin dioxide. S2. Functional component premixing: The epoxy-acetal dual-effect amine-scavenging copolymer and the sulfonated amino polyethylene glycol ester doped stable copolymer are weighed at a mass ratio of 1:1 and premixed in a high-speed mixer at room temperature for 10-20 min to obtain the premixed functional component. S3. Overall premixing: The premixed functional components obtained in step S2, polyaniline, hindered phenolic antioxidant, polyethyleneimine-modified nano-hydroxyapatite, and the surface-treated antimony-doped tin dioxide obtained in step S1 are added to a high-speed mixer and mixed at room temperature for 10-20 minutes to obtain the functional component premix. S4. Melt extrusion granulation: The functional component premix obtained in step S3, fluororesin matrix, and polytetrafluoroethylene micro powder are added to a twin-screw extruder and melt-blended and extruded at 260~280℃ and screw speed of 60~80r / min. The residence time is controlled at 3~5min. After extrusion granulation, a transparent and durable antistatic filter rod conveying pipe composite material is obtained.

[0013] Furthermore, if perfluoroalkoxy resin is selected as the fluororesin base material, the processing temperature of the twin-screw extruder is 260~280℃; if tetrafluoroethylene-hexafluoropropylene copolymer is selected as the fluororesin base material, the processing temperature of the twin-screw extruder is 340~380℃.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention utilizes an epoxy-acetal dual-effect amine-capturing copolymer and a sulfonated amino polyethylene glycol ester doped and stabilized copolymer to synergistically block the erosion of the conductive function of polyaniline by volatile nitrogen-containing components in tobacco and filter rods at the source. At the same time, it continuously and actively compensates for the localized attenuation of conductivity that has already occurred, effectively solving the core problem of the failure of the conductive function of polyaniline in a closed tobacco conveying environment and extending the antistatic functional life of the composite pipe material.

[0015] 2. The polyethyleneimine-modified nano-hydroxyapatite introduced in this invention enhances the function of the above-mentioned synergistic mechanism. The composite material of this invention uses fluororesin as the base material. While maintaining good optical transparency, it achieves effective antistatic performance at low addition levels through the synergistic compounding of inorganic and organic conductive components. Through the synergistic protection system of the three components, the composite material can maintain a long-lasting and stable antistatic function in the service environment where volatile nitrogen-containing components of tobacco and filter rods are enriched for a long time. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the preparation process of a transparent, durable antistatic filter rod delivery pipeline composite material according to Embodiment 1 of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1: This example discloses a transparent, durable antistatic filter rod conveying pipe composite material, comprising the following parts by weight: 86.0 parts of fluororesin substrate, 5.0 parts of antimony-doped tin dioxide, 1.0 part of polyaniline, 1.0 part of epoxy-acetal dual-effect amine-capturing copolymer, 1.0 part of sulfonated amino polyethylene glycol ester doped stable copolymer, 0.6 parts of polyethyleneimine modified nano-hydroxyapatite, 1.2 parts of polytetrafluoroethylene micro powder, 0.5 parts of titanate coupling agent, and 0.3 parts of hindered phenolic antioxidant.

[0019] The preparation method of the epoxy-acetal dual-effect amine-scavenging copolymer includes the following steps: S11. Dissolve 17.2 g of methacrylic acid, 17.6 g of 4-hydroxybutyraldehyde and 0.38 g of p-toluenesulfonic acid in 150 mL of toluene. Add 0.034 g of hydroquinone methyl ether as a polymerization inhibitor. Assemble a Dean-Stark water separator and reflux at 110 °C for 8 h. Azeotropic dehydration drives the esterification equilibrium to shift towards the product. After the reaction is complete, cool to room temperature and wash twice with saturated sodium bicarbonate aqueous solution (50 mL each time) and twice with deionized water (50 mL each time). Dry the organic layer with 10 g of anhydrous magnesium sulfate for 30 min and filter. Remove toluene by vacuum distillation. Add 0.010 g of hydroquinone methyl ether and purify by short-path vacuum distillation (boiling point about 95~100 °C / 0.8 mmHg) to obtain intermediate 1. S12. Dissolve 17.0 g of intermediate 1 and 9.3 g of ethylene glycol in 120 mL of toluene, add 0.19 g of p-toluenesulfonic acid as an acid catalyst and 0.026 g of hydroquinone methyl ether as a polymerization inhibitor, assemble a Dean-Stark water separator, reflux at 110 °C for 10 h, remove water by azeotropic distillation, cool to room temperature after the reaction is complete, wash twice with saturated sodium bicarbonate aqueous solution (50 mL each time) and twice with deionized water (50 mL each time), dry the organic layer with 10 g of anhydrous magnesium sulfate and filter, remove toluene by vacuum distillation, add 0.010 g of hydroquinone methyl ether and purify by short-path vacuum distillation (boiling point about 125~130 °C / 0.8 mmHg) to obtain intermediate 2; S13. Dissolve 19.9 g glycidyl methacrylate, 5.5 g maleic anhydride, and 25.4 g intermediate 2 in 180 mL of 1,4-dioxane dried for 48 h using a 4 Å molecular sieve. Add 0.46 g azobisisobutyronitrile and place in an ice-water bath. After bubbling with high-purity nitrogen for 40 min to remove oxygen, heat to 70 °C and react under nitrogen protection with magnetic stirring for 14 h. After the reaction is complete, cool to room temperature and slowly add the reaction solution to 700 mL of anhydrous diethyl ether to precipitate. Collect the white solid by filtration. Redissolve the solid in 80 mL of dried 1,4-dioxane and add it to 400 mL of anhydrous diethyl ether again to precipitate. Repeat the above reprecipitation operation three times to fully remove residual maleic anhydride monomer (maleic anhydride has a certain solubility in diethyl ether, and a single precipitation is not enough to completely remove it). The final solid is dried under vacuum at 40 °C for 24 h to obtain an epoxy-acetal bis-amine scavenging copolymer.

[0020] The preparation method of the sulfonated amino polyethylene glycol ester doped stable copolymer includes the following steps: S21. Dissolve 18.2 g of aminoethyl acrylate hydrochloride in a mixed solvent of 100 mL tetrahydrofuran and 100 mL deionized water, place in an ice-water bath, add 15.2 mL of triethylamine to neutralize, and then slowly add 26.2 g of di-tert-butyl dicarbonate in a solution of 50 mL tetrahydrofuran. After the addition is complete, remove the ice bath and stir the reaction at 25 °C for 12 h. After the reaction is complete, evaporate the tetrahydrofuran first on a rotary evaporator (35 °C, reduced pressure), then add 100 mL of deionized water to dilute, extract three times with 100 mL of ethyl acetate, combine the organic phases, wash twice with 5% citric acid aqueous solution (60 mL each time) and once with 60 mL of saturated brine, dry the organic layer with 15 g of anhydrous magnesium sulfate for 30 min and filter, add 0.010 g of hydroquinone methyl ether and evaporate ethyl acetate under reduced pressure, dry under vacuum at 25 °C for 12 h to obtain intermediate 3; S22. Dissolve 10.3g sodium styrene sulfonate, 4.6g intermediate 3 and 12.0g polyethylene glycol methacrylate (average molecular weight 400g / mol) in 180mL of a mixed solvent of deionized water and ethanol (volume ratio 2:1). Add 0.56g 4,4'-azobis(4-cyanopentanoic acid) as a water-soluble free radical initiator. After purging with high-purity nitrogen gas for 30min to remove oxygen, heat to 65℃ and react at a constant temperature for 20h. After the reaction is complete, put the reaction solution into a dialysis bag with a molecular weight cutoff of 3500Da and dialyze with deionized water for 48h (changing the water every 12h). Freeze-dry the dialysate to obtain the copolymer precursor. S23. Dissolve the copolymer precursor in deionized water to prepare a 5% aqueous solution. Pass the solution at a flow rate of 5 mL / min through a strong acid cation exchange resin column (hydrogen form, Dowex 50W-X8, column volume approximately 200 mL), which has been pre-regenerated with 500 mL of 1 mol / L hydrochloric acid and then thoroughly washed with deionized water until the pH of the eluent is 6-7. Elute with deionized water until the pH of the eluent is stable. Collect all the eluents, combine them, and freeze-dry to completely convert the sodium sulfonate groups into sulfonic acid groups, obtaining the ion-exchange intermediate. S24. Dissolve the ion-exchange intermediate in 100 mL of dichloromethane and place it in an ice-water bath. Slowly add 8.0 mL of trifluoroacetic acid in a fume hood, remove the ice bath, and stir the reaction at 25 °C for 2 h. Immediately after the reaction is complete, slowly add the solution dropwise to 200 mL of saturated sodium bicarbonate aqueous solution to neutralize the residual trifluoroacetic acid. After thorough stirring, put the mixture into a dialysis bag with a molecular weight cutoff of 3500 Da and dialyze it with deionized water for 48 h (changing the water every 12 h). Freeze-dry the dialysate to obtain a sulfonated amino polyethylene glycol ester doped stable copolymer.

[0021] The preparation method of the polyethyleneimine-modified nano-hydroxyapatite is as follows: 10.0g of nano-hydroxyapatite powder is dispersed in 200mL of deionized water and ultrasonically dispersed for 30min to obtain a uniform suspension. Separately, 6.0g of polyethyleneimine is dissolved in 50mL of deionized water and slowly added dropwise to the above suspension. The mixture is stirred and reacted at 25℃ for 24h, so that the polyethyleneimine chain segments are adsorbed onto the particle surface through electrostatic interaction and hydrogen bonding between the amino group and the phosphate group on the surface of hydroxyapatite. After the reaction is completed, the precipitate is collected by centrifugation at 10000r / min for 15min. The precipitate is washed three times with deionized water (100mL each time) to remove free polyethyleneimine. The precipitate is then vacuum dried at 60℃ for 12h to obtain polyethyleneimine-modified nano-hydroxyapatite.

[0022] The nano-hydroxyapatite has a particle size of 20-50 nm and a specific surface area of ​​not less than 80 m² / g; the polyethyleneimine has a number-average molecular weight of 600 g / mol.

[0023] The method for preparing the transparent, durable antistatic filter rod conveying pipe composite material includes the following steps: S1. Inorganic component surface treatment: Antimony-doped tin dioxide and isopropyltris(dioctylpyrophosphoryloxy)titanate (titanate coupling agent) are added to a high-speed mixer and premixed at 75~85℃ for 25~35min to make the titanate coupling agent uniformly coat the surface of antimony-doped tin dioxide particles, and the surface-treated antimony-doped tin dioxide is obtained. S2. Functional component premixing: The epoxy-acetal dual-effect amine-scavenging copolymer and the sulfonated amino polyethylene glycol ester doped stable copolymer are weighed at a mass ratio of 1:1 and premixed in a high-speed mixer at room temperature for 10-20 min to obtain the premixed functional component. S3. Overall premixing: The premixed functional components obtained in step S2, along with polyaniline, pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid) (hindered phenolic antioxidant), polyethyleneimine-modified nano-hydroxyapatite, and the surface-treated antimony-doped tin dioxide obtained in step S1, are added to a high-speed mixer and mixed at room temperature for 10-20 minutes to obtain the functional component premix. S4. Melt Extrusion Granulation: The functional component premix obtained in step S3, along with tetrafluoroethylene-hexafluoropropylene copolymer (fluororesin matrix) and polytetrafluoroethylene micro powder, are added to a twin-screw extruder. The mixture is melt-blended and extruded at 260-280℃ and a screw speed of 60-80 r / min, with a residence time controlled at 3-5 min. The resulting material is then extruded and granulated to obtain a transparent, durable antistatic filter rod conveying pipe composite material. The preparation process is as follows: Figure 1 As shown.

[0024] Example 2: This example differs from Example 1 in that it includes the following components by weight: 82.0 parts of fluororesin substrate, 3.0 parts of antimony-doped tin dioxide, 0.5 parts of polyaniline, 0.5 parts of epoxy-acetal dual-effect amine-capturing copolymer, 0.5 parts of sulfonated amino polyethylene glycol ester doped stable copolymer, 0.3 parts of polyethyleneimine modified nano-hydroxyapatite, 0.5 parts of polytetrafluoroethylene micro powder, 0.2 parts of titanate coupling agent, and 0.1 parts of hindered phenolic antioxidant; other components and preparation methods are the same as in Example 1.

[0025] Example 3: This example differs from Example 1 in that it includes the following components by weight: 91.0 parts of fluororesin substrate, 7.0 parts of antimony-doped tin dioxide, 2.0 parts of polyaniline, 1.5 parts of epoxy-acetal dual-effect amine-capturing copolymer, 1.5 parts of sulfonated amino polyethylene glycol ester doped stable copolymer, 1.0 part of polyethyleneimine modified nano-hydroxyapatite, 2.0 parts of polytetrafluoroethylene micro powder, 0.8 parts of titanate coupling agent, and 0.5 parts of hindered phenolic antioxidant; other components and preparation methods are the same as in Example 1.

[0026] Example 4: This example is based on Example 1, but differs from Example 1 in that a tetrafluoroethylene-hexafluoropropylene copolymer is used as the fluororesin base material, and the processing temperature of the twin-screw extruder in step S4 is 340~380℃; other components and preparation methods are the same as in Example 1.

[0027] Comparative Example 1: This comparative example differs from Example 1 in that a copolymer containing only epoxy and maleic anhydride units (denoted as epoxy-maleic anhydride copolymer) is used instead of the epoxy-acetal bis-amine scavenger copolymer. That is, the synthetic route skips steps S11 and S12, intermediates 1 and 2 are not prepared, and acetal is not introduced to protect the latent aldehyde unit.

[0028] The preparation method of epoxy-maleic anhydride copolymer is as follows: Glycidyl methacrylate and maleic anhydride are dissolved in 1,4-dioxane dried through a 4 Å molecular sieve. Azobisisobutyronitrile (the amount is the same as in step S13 of Example 1) is added, and the mixture is placed in an ice-water bath. After purging with high-purity nitrogen to remove oxygen, the temperature is raised to 70°C, and the reaction is carried out under nitrogen protection with constant temperature magnetic stirring. After the reaction is completed, the mixture is cooled to room temperature, and the reaction solution is slowly added dropwise to anhydrous diethyl ether to precipitate. The white solid is collected by filtration. The solid is redissolved in dried 1,4-dioxane and added dropwise to anhydrous diethyl ether again to precipitate. The above reprecipitation operation is repeated three times. The final solid is dried under vacuum to obtain epoxy-maleic anhydride copolymer. The amounts of other components and the preparation method are the same as in Example 1.

[0029] Comparative Example 2: This comparative example differs from Example 1 in that a copolymer containing only acetal protecting units and maleic anhydride units (denoted as acetal-maleic anhydride copolymer) is used instead of the epoxy-acetal bis-amine scavenging copolymer. That is, glycidyl methacrylate is not added in step S13 of the synthetic route, and no epoxy units are introduced. The preparation methods for steps S11 and S12 are exactly the same as in Example 1, and the resulting intermediate 2 is the same.

[0030] The preparation method of the acetal-maleic anhydride copolymer is as follows: Intermediate 2 is prepared according to the same operation as steps S11 and S12 in Example 1; Intermediate 2 and maleic anhydride are dissolved in 1,4-dioxane dried through a 4 Å molecular sieve (glycidyl methacrylate is omitted), and azobisisobutyronitrile (the amount is the same as in step S13 of Example 1) is added. The mixture is placed in an ice-water bath, and after bubbling with high-purity nitrogen to remove oxygen, the temperature is raised to 70°C, and the reaction is carried out under nitrogen protection with constant temperature magnetic stirring. The post-treatment steps (reprecipitation purification, vacuum drying) are exactly the same as in step S13 of Example 1 to obtain the acetal-maleic anhydride copolymer. The amounts and preparation methods of the remaining components are the same as in Example 1.

[0031] Comparative Example 3: This comparative example differs from Example 1 in that the synthesis of the sulfonated amino polyethylene glycol ester doped stable copolymer skips step S23 (strong acid cation exchange resin column treatment), the sulfonic acid group remains in the form of sodium sulfonate (-SO3Na), and the resulting copolymer (denoted as sodium sulfonate type copolymer) replaces the sulfonated amino polyethylene glycol ester doped stable copolymer.

[0032] The preparation method of the sodium sulfonate copolymer is as follows: Following the exact same steps as in Example 1, proceed sequentially with S21 (amino Boc protection, to obtain intermediate 3) and S22 (free radical copolymerization, to obtain the copolymer precursor), skipping S23. After freeze-drying the copolymer precursor dialysate, dissolve it directly in dichloromethane and place it in an ice-water bath. In a fume hood, slowly add trifluoroacetic acid following the exact same procedure as in step S24 of Example 1 to remove the Boc protecting group. The post-treatment steps are the same as in step S24 of Example 1. Finally, freeze-dry to obtain the sodium sulfonate copolymer. The amounts and preparation methods of the remaining components are the same as in Example 1.

[0033] Comparative Example 4: This comparative example differs from Example 1 in that step S24 (trifluoroacetic acid deBoc step) is skipped in the synthesis of the sulfonated amino polyethylene glycol ester doped stable copolymer. The amino group remains in a Boc protected state, and the resulting copolymer (denoted as Boc protected copolymer) replaces the sulfonated amino polyethylene glycol ester doped stable copolymer.

[0034] The preparation method of the Boc protected copolymer is as follows: Following the exact same steps as in Example 1, proceed sequentially through S21 (to obtain intermediate 3), S22 (to obtain the copolymer precursor), and S23 (ion exchange, converting the sulfonic acid groups to the proton form, to obtain the ion-exchanged intermediate), skipping S24. The ion-exchanged intermediate obtained in S23 is directly freeze-dried to obtain the Boc protected copolymer. The amounts and preparation methods of the remaining components are the same as in Example 1.

[0035] Comparative Example 5: This comparative example differs from Example 1 in that unmodified nano-hydroxyapatite (particle size 20~50nm, specific surface area not less than 80m² / g) directly replaces polyethyleneimine-modified nano-hydroxyapatite, and the amount used is the same as in Example 1.

[0036] Unmodified nano-hydroxyapatite, without any chemical modification, was weighed directly according to the amount of polyethyleneimine-modified nano-hydroxyapatite in Example 1, and added together with other functional components in step S3 to a high-speed mixer for mixing. The amount and preparation method of the remaining components were the same as in Example 1.

[0037] Comparative Example 6: This comparative example differs from Example 1 in that it does not include the epoxy-acetal dual-effect amine scavenging copolymer, while the amounts of other components are the same as in Example 1.

[0038] Comparative Example 7: This comparative example differs from Example 1 in that it does not include the sulfonated amino polyethylene glycol ester doped stable copolymer, while the amounts of other components are the same as in Example 1.

[0039] Comparative Example 8: This comparative example differs from Example 1 in that it does not include the epoxy-acetal dual-effect amine-capturing copolymer and the sulfonated amino polyethylene glycol ester doped stable copolymer, while the other components and amounts are the same as in Example 1.

[0040] Comparative Example 9: This comparative example differs from Example 1 in that it does not include polyethyleneimine-modified nano-hydroxyapatite, while the amounts of other components are the same as in Example 1.

[0041] Comparative Example 10: This comparative example differs from Example 1 in that it does not include the epoxy-acetal dual-effect amine-capturing copolymer, the sulfonated amino polyethylene glycol ester doped stable copolymer, and the polyethyleneimine modified nano-hydroxyapatite. The amounts of other components are the same as in Example 1.

[0042] Experimental verification: Experiment 1: Verify the antistatic durability of the present invention under simulated exposure to volatile amines in tobacco.

[0043] The detection indicators and methods are as follows: The granules obtained from extrusion granulation of each formulation were hot-pressed into thin sheets with a thickness of (1.0±0.05) mm on a two-roller tablet press. The sheets were then cut into 100 mm × 100 mm square samples, with 6 samples prepared in parallel for each group. The samples were placed in a sealed constant temperature and humidity aging chamber, which was circulated with a simulated tobacco volatile amine mixture atmosphere (50 ppm ammonia, 20 ppm methylamine, 10 ppm trimethylamine, nitrogen balance, relative humidity 60%±5%, temperature 40℃±1℃) precisely controlled by a mass flow meter, and continuously exposed. Samples were taken from the corresponding groups at 0h, 500h, 1000h, and 2000h respectively. After equilibration in a standard environment (temperature 23℃±2℃, relative humidity 50%±5%) for 24h, the surface resistivity (Ω / sq) of the samples was measured using a high-resistivity meter (applied voltage 100V) in accordance with GB / T 1410—2006. The average range of data for each group of 6 samples was reported. The antistatic function failure was judged when the surface resistivity exceeded 1×10¹¹Ω / sq at 2000h. The results are shown in Table 1.

[0044] Table 1. Surface resistivity of each sample under simulated tobacco volatile amine exposure environment:

[0045] It should be noted that, although Comparative Examples 5 and 9 marked "Not Expired ※" in Table 1 do not exceed 1×10 11The failure threshold was Ω / sq, but the surface resistivity increased by about 73-83 times and 29-35 times respectively after 2000h compared to 0h, which is much greater than the 1.2-8.8 times of Examples 1-4. This indicates that the absence or incomplete modification of the synergistic component significantly weakened the long-term functional maintenance ability, which is essentially different from the Examples.

[0046] As shown in Table 1, after 2000 hours of continuous amine exposure, the surface resistivity of Examples 1-4 remained at 8.1 × 10⁻⁶. 8 ~1.5×10 9 Within the Ω / sq range, all were determined to have intact antistatic function, proving that the technical solution of this invention effectively solves the core problem of continuous failure of the conductive function of polyaniline in a closed tobacco conveying environment.

[0047] Experiment 2: Verify the basic properties of the composite material of the present invention. The results are shown in Table 2.

[0048] The detection indicators and methods are as follows: Visible light transmittance test: The extruded granules from Examples 1 to 4 were hot-pressed into thin sheets with a thickness of (1.0±0.02) mm, and cut into 50 mm × 50 mm square samples. Three samples were prepared in parallel for each group. The transmittance (%) was measured at a wavelength of 550 nm using a UV-Vis spectrophotometer in accordance with GB / T 2410—2008. The average range of the three samples was reported.

[0049] Dynamic friction coefficient test: The extruded granules from Examples 1-4 were hot-pressed into flat plates with a thickness of (3.0±0.1) mm, and cut into 100 mm × 60 mm rectangles. Five parallel plates were prepared for each group. According to GB / T 10006—2021, Q235 steel plate was used as the mating material, with a normal load of 200 g and a sliding speed of 100 mm / min. The dynamic friction coefficient was measured, and the mean range of the data from the five plates was reported.

[0050] Initial surface resistivity: The 0h data from Examples 1-4 in Experiment 1 are directly cited.

[0051] Table 2. Basic properties of the composite material of the present invention:

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A transparent, durable antistatic filter rod conveying pipe composite material, characterized in that, The product comprises the following components by weight: 82.0-91.0 parts of fluororesin base material, 3.0-7.0 parts of antimony-doped tin dioxide, 0.5-2.0 parts of polyaniline, 0.5-1.5 parts of epoxy-acetal dual-effect amine-capturing copolymer, 0.5-1.5 parts of sulfonated amino polyethylene glycol ester doped stable copolymer, 0.3-1.0 parts of polyethyleneimine modified nano-hydroxyapatite, 0.5-2.0 parts of polytetrafluoroethylene micro powder, 0.2-0.8 parts of titanate coupling agent, and 0.1-0.5 parts of hindered phenolic antioxidant.

2. The transparent, durable antistatic filter rod conveying pipe composite material according to claim 1, characterized in that, The preparation method of the epoxy-acetal dual-effect amine-scavenging copolymer includes the following steps: S11. Methacrylic acid, 4-hydroxybutyraldehyde and p-toluenesulfonic acid were dissolved in toluene, hydroquinone methyl ether was added as a polymerization inhibitor, a Dean-Stark water separator was assembled, and the reaction was refluxed at 110°C. Water was removed by azeotropic distillation. After the reaction was completed, the mixture was cooled to room temperature and washed successively with saturated sodium bicarbonate aqueous solution and deionized water. The organic layer was dried with anhydrous magnesium sulfate and filtered. Toluene was removed by vacuum distillation. Hydroquinone methyl ether was added and the mixture was purified by short-path vacuum distillation to obtain intermediate 1. S12. Intermediate 1 and ethylene glycol were dissolved in toluene, p-toluenesulfonic acid was added as an acid catalyst and hydroquinone methyl ether as a polymerization inhibitor, a Dean-Stark water separator was assembled, and the reaction was refluxed at 110°C. Water was removed by azeotropic distillation. After the reaction was completed, the mixture was cooled to room temperature and washed successively with saturated sodium bicarbonate aqueous solution and deionized water. The organic layer was dried with anhydrous magnesium sulfate and filtered. Toluene was removed by vacuum distillation. After adding hydroquinone methyl ether, the mixture was purified by short-path vacuum distillation to obtain intermediate 2. S13. Glycidyl methacrylate, maleic anhydride, and intermediate 2 were dissolved in 1,4-dioxane dried through a 4 Å molecular sieve. Azobisisobutyronitrile was added, and the mixture was placed in an ice-water bath. After purging with high-purity nitrogen to remove oxygen, the temperature was raised to 70°C, and the reaction was carried out under nitrogen protection with magnetic stirring at a constant temperature. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was slowly added dropwise to anhydrous diethyl ether to precipitate. The white solid was collected by filtration. The solid was redissolved in dried 1,4-dioxane and added dropwise to anhydrous diethyl ether to precipitate again. The above recrystallization operation was repeated three times. The final solid was dried under vacuum to obtain an epoxy-acetal bis-amine scavenging copolymer.

3. The transparent, durable antistatic filter rod conveying pipe composite material according to claim 1, characterized in that, The preparation method of the sulfonated amino polyethylene glycol ester doped stable copolymer includes the following steps: S21. Dissolve aminoethyl acrylate hydrochloride in a mixed solvent of tetrahydrofuran and deionized water, place in an ice-water bath, add triethylamine to neutralize, and then slowly add a tetrahydrofuran solution of di-tert-butyl dicarbonate. After the addition is complete, remove the ice bath and stir the reaction at 25°C. After the reaction is complete, evaporate by rotary evaporation, add deionized water to dilute, extract three times with ethyl acetate, combine the organic phases, wash successively with 5% citric acid aqueous solution and saturated brine, dry the organic layer with anhydrous magnesium sulfate and filter, add hydroquinone methyl ether and evaporate under reduced pressure, then dry under vacuum to obtain intermediate 3; S22. Sodium styrene sulfonate, intermediate 3 and polyethylene glycol methacrylate were dissolved in a mixed solvent of deionized water and ethanol. 4,4'-azobis(4-cyanovaleric acid) was added as a water-soluble free radical initiator. After bubbling with high-purity nitrogen to remove oxygen, the temperature was raised to 65°C and reacted at a constant temperature. After the reaction was completed, the mixture was dialyzed with deionized water. The dialysate was freeze-dried to obtain the copolymer precursor. S23. Dissolve the copolymer precursor in deionized water and pass it through a strong acid cation exchange resin column that has been regenerated with 1 mol / L hydrochloric acid and then thoroughly washed with deionized water until the pH of the eluent is 6-7 at a flow rate of 5 mL / min. Elute with deionized water until the pH of the eluent is stable. Collect all the eluents, combine them, and freeze-dry to obtain the ion-exchange intermediate. S24. Dissolve the ion-exchange intermediate in dichloromethane and place it in an ice-water bath. Slowly add trifluoroacetic acid in a fume hood, remove the ice bath, and stir the reaction at 25°C. Immediately after the reaction is complete, slowly add the solution dropwise to a saturated sodium bicarbonate aqueous solution to neutralize the residual trifluoroacetic acid. After thorough stirring, dialyze with deionized water and freeze-dry the dialysate to obtain a sulfonated amino polyethylene glycol ester doped stable copolymer.

4. The transparent, durable antistatic filter rod conveying pipe composite material according to claim 1, characterized in that, The preparation method of the polyethyleneimine modified nano-hydroxyapatite is as follows: nano-hydroxyapatite powder is dispersed in deionized water and ultrasonically dispersed to obtain a uniform suspension. Polyethyleneimine is dissolved in deionized water and slowly added dropwise to the above suspension. The mixture is stirred and reacted at 25°C. After the reaction is completed, the precipitate is collected by centrifugation, washed with deionized water, and vacuum dried to obtain polyethyleneimine modified nano-hydroxyapatite.

5. The transparent, durable antistatic filter rod conveying pipe composite material according to claim 4, characterized in that, The nano-hydroxyapatite has a particle size of 20-50 nm and a specific surface area of ​​not less than 80 m² / g; the polyethyleneimine has a number-average molecular weight of 600 g / mol.

6. The transparent, durable antistatic filter rod conveying pipe composite material according to claim 1, characterized in that, The fluororesin substrate is one of perfluoroalkoxy resin or tetrafluoroethylene-hexafluoropropylene copolymer; the hindered phenolic antioxidant is pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid); and the titanate coupling agent is isopropyltris(dioctylpyrophosphate)titanate.

7. A method for preparing a transparent, durable antistatic filter rod conveying pipe composite material according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Inorganic component surface treatment: Antimony-doped tin dioxide and titanate coupling agent are added to a high-speed mixer and premixed at 75~85℃ for 25~35min to obtain surface-treated antimony-doped tin dioxide. S2. Functional component premixing: The epoxy-acetal dual-effect amine-scavenging copolymer and the sulfonated amino polyethylene glycol ester doped stable copolymer are weighed at a mass ratio of 1:1 and premixed in a high-speed mixer at room temperature for 10-20 min to obtain the premixed functional component. S3. Overall premixing: The premixed functional components obtained in step S2, polyaniline, hindered phenolic antioxidant, polyethyleneimine-modified nano-hydroxyapatite, and the surface-treated antimony-doped tin dioxide obtained in step S1 are added to a high-speed mixer and mixed at room temperature for 10-20 minutes to obtain the functional component premix. S4. Melt extrusion granulation: The functional component premix obtained in step S3, fluororesin matrix, and polytetrafluoroethylene micro powder are added to a twin-screw extruder and melt-blended and extruded at 260~380℃ and screw speed of 60~80r / min. The residence time is controlled at 3~5min. After extrusion granulation, a transparent and durable antistatic filter rod conveying pipe composite material is obtained.

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