Anti-aging anti-static film and production process thereof

Abstract

The invention relates to the field of high polymer material processing, and discloses an anti-aging and anti-static film and a production process thereof, and the anti-aging and anti-static film comprises the following components: 85-97 parts of base resin; 2-10 parts of an antistatic functional main chain precursor; 0.2 to 2 parts of a grafting precursor with an anti-aging function; 0.5 to 3 parts of a synergistic agent; 0.01 to 0.1 part of a catalyst, wherein the main chain precursor with the antistatic function is a polypropylene carbonate-polyethylene oxide copolymer; the anti-aging functional grafting precursor is a hindered amine compound with a reactive functional group, and the hindered amine compound with the reactive functional group is 2, 2, 6, 6-tetramethyl-4-isocyanate piperidine. A hindered amine molecule with an isocyanate group and a polyether carbonate copolymer are used as reaction precursors, and in subsequent processing, through an in-situ grafting reaction, a single and dual-function synergistic high-molecular auxiliary agent is generated, so that deep synergy of anti-aging and antistatic properties is achieved.

Description

Technical Field

[0001] The invention relates to the field of polymer material processing, in particular to an anti-aging antistatic film and a production process thereof. Background Art

[0002] Polymer films have been widely used in agricultural covering, product packaging, electronic device protection and other fields due to their advantages such as light weight, flexibility and low cost. However, in many application scenarios, the functionality of general polymer materials themselves cannot meet the requirements of use. For example, most polymer materials are insulators, and their surfaces are very prone to generate and accumulate static charges due to friction during production and use. This will not only absorb dust and affect the cleanliness of the product, but in severe cases it may even cause sparks due to electrostatic discharge (ESD), causing irreversible damage to electronic components or posing a safety hazard in flammable and explosive environments. At the same time, under the long-term influence of environmental factors such as light, heat, and oxygen, the molecular chains of polymer materials will degrade and break, resulting in a sharp decline in the mechanical properties of the material, yellowing and brittleness, and greatly shortening its effective service life.

[0003] To achieve these dual functions, the industry's standard practice is to physically blend antistatic agents and antioxidants (usually hindered amine light stabilizers (HALS)) into the base resin. While this simple physical blending approach was effective in the early stages of film development, its inherent drawbacks have become increasingly apparent as demands for film performance and lifespan continue to rise.

[0004] During the study, it was found that in order to obtain a permanent antistatic effect that is not affected by environmental humidity, the technological trend has shifted from the use of easily migrating small molecule antistatic agents to the use of high-molecular-weight permanent antistatic agents (such as polyether copolymers). However, the problem arises that such high-molecular-weight antistatic agents themselves or the catalysts remaining in their synthesis process often have a certain acidity. The active center of the hindered amine light stabilizer (HALS) is the secondary or tertiary amine group on the piperidine ring, and its chemical nature is alkaline. Therefore, when these two additives meet during the high-temperature melt blending process, an acid-base neutralization reaction is inevitable. This chemical "antagonistic effect" will "poison" both additives at the same time, resulting in a significant decrease in the light stabilizer's ability to capture free radicals and the destruction of the antistatic agent's ion conduction pathway. Ultimately, the film's anti-aging and antistatic properties fall far short of the design expectations, and true long-term synergy cannot be achieved. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides an anti-aging and antistatic film and its production process, which solves the technical problems in traditional technology that the performance of both additives is attenuated due to the chemical antagonism between anti-aging agents and antistatic agents, and the rough and uncontrollable reaction extrusion process.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: an anti-aging antistatic film, comprising the following components:

[0007] Base resin: 85-97 parts;

[0008] Antistatic functional main chain precursor: 2-10 parts;

[0009] Anti-aging functional grafting precursor: 0.2-2 parts;

[0010] Synergist: 0.5-3 parts;

[0011] Catalyst: 0.01-0.1 parts.

[0012] Furthermore, the core of the design of this composition is that it is not a simple physical blend, but a reaction precursor system for subsequent "in-situ reaction". The base resin is the structural skeleton of the film and provides the main mechanical properties. The antistatic functional main chain precursor and the anti-aging functional graft precursor are two separately designed "semi-finished products" with specific reactivity. In the subsequent processing, they will be chemically bonded under the action of a catalyst to form the final, single-molecule bifunctional additive. The synergist provides the necessary physical environment for the reaction to occur and the stable dispersion of the product in the base resin. This formulation system fundamentally transforms the final functional realization method from traditional "physical mixing" to "chemical synthesis."

[0013] Preferably, the antistatic functional main chain precursor is a polypropylene carbonate-polyethylene oxide copolymer; and the anti-aging functional graft precursor is a hindered amine compound with a reactive functional group.

[0014] Furthermore, the choice of polypropylene carbonate-polyethylene oxide copolymer (PPC-PEO) as the main chain precursor takes advantage of its unique dual properties: its polyethylene oxide (PEO) segment itself has the ability to achieve antistatic properties through an ion conduction mechanism, providing a permanent antistatic effect that is not affected by environmental humidity; at the same time, the active points (such as hydroxyl groups) contained in its molecular structure provide "anchor points" for subsequent chemical grafting reactions. The choice of hindered amine compounds with reactive functional groups (HALS) as grafting precursors takes advantage of the anti-aging ability of HALS as a highly effective free radical scavenger, and through the reactive functional groups it carries, it is firmly "welded" to the antistatic main chain in the form of a covalent bond, thus solving the problem of easy migration and failure of traditional HALS additives.

[0015] Preferably, the hindered amine compound with a reactive functional group is 2,2,6,6-tetramethyl-4-isocyanate piperidine.

[0016] Furthermore, the isocyanate group (-NCO) was chosen as the reactive functional group on the hindered amine compound because it has extremely high reactivity and can undergo an efficient addition reaction with the hydroxyl groups (-OH) on the PPC-PEO main chain within the limited residence time of the twin-screw extruder, forming a highly chemically stable urethane bond (-NH-COO-). This highly efficient reaction ensures that the anti-aging unit can be successfully and firmly grafted onto the antistatic main chain, which is the key chemical link to realize the concept of "in situ synthesis."

[0017] Preferably, the synergist is a polar-modified polyolefin.

[0018] Furthermore, the polar-modified polyolefin plays the role of an "interface bridge" in this system. The non-polar polyolefin long chain in its molecular structure has good physical compatibility with the non-polar base resin (such as polyethylene); while the polar groups on its molecule have a strong interaction with the polar antistatic functional main chain precursor (PPC-PEO). This amphiphilic structure enables it to form a stable interface layer between the base resin and the functional precursor, inhibiting the agglomeration of the functional precursor due to polar incompatibility, ensuring that it can form a microscopic, uniform, and interpenetrating physical network in the base resin, laying the structural foundation for subsequent uniform reactions and functional performance.

[0019] Preferably, the polar-modified polyolefin is maleic anhydride-grafted polyethylene wax or maleic anhydride-grafted polyolefin elastomer.

[0020] Furthermore, maleic anhydride (MAH) was chosen as the polar group for modification because the MAH group has strong polarity and can generate strong dipole-dipole interactions with the ether bonds and ester groups in the PPC-PEO molecular chain, thereby achieving strong physical anchoring. Using polyethylene wax or polyolefin elastomer as the backbone provides a means to adjust the processing fluidity and mechanical properties of the final film. Preparation of the antistatic functional main chain precursor (PPC-PEO);

[0021] 200 g of refined toluene and 1.0 g of zinc-cobalt double metal cyanide (Zn-CoDMC) catalyst were added to a thoroughly dried and nitrogen-purged 5 L autoclave. The temperature was raised to 80°C with stirring, and a mixture of 2000 g of propylene oxide (PO) and 3000 g of ethylene oxide (EO) was added dropwise at a rate of 10 g / min. Simultaneously, carbon dioxide (CO2) was introduced into the autoclave at a pressure of 5.0 MPa. During the reaction, the reaction temperature was maintained at 80 ± 5°C using jacket cooling water. After the addition was complete, the reaction was continued at the same temperature and pressure for 5 hours.

[0022] After the reaction, the temperature and pressure were lowered, and the reaction product was transferred to a rotary evaporator. The solvent and unreacted monomers were removed at 80°C and -0.09 MPa to obtain a colorless, transparent, viscous liquid product, namely polypropylene carbonate-polyethylene oxide copolymer (PPC-PEO). The number average molecular weight of the product was 12,000 g / mol as determined by gel permeation chromatography (GPC). The product was characterized by hydrogen nuclear magnetic resonance spectroscopy (HNMR). 1 HNMR) analysis and calculation showed that the mass fraction of the polyethylene oxide (PEO) segment was 73%.

[0023] The production process of the anti-aging antistatic film is carried out in a twin-screw extruder having at least two independent feed ports, comprising the following steps:

[0024] Step S1, physical blending and network construction step: adding a mixture of the base resin, the antistatic functional main chain precursor and the synergist from the first feed port of the extruder, and melt blending in the melt dispersion zone at the front end of the extruder to form a physically dispersed functional network structure;

[0025] Step S2, targeted injection and in-situ reaction step: injecting the anti-aging functional graft precursor and catalyst into the melt formed by the material in step S1 at a second feed port downstream of the extruder, and performing an in-situ grafting reaction in the reaction zone of the extruder to generate a bifunctional polymer additive;

[0026] Step S3, devolatilization and purification step: devolatilization treatment is performed on the melt after the reaction in step S2 to remove by-products or unreacted substances;

[0027] Step S4, homogenization and molding step: homogenize the melt after the material treatment in step S3, and extrude it through a die to form a film.

[0028] Furthermore, the core of the process lies in its logic of "partitioning and sequencing". Step S1 is in the high shear zone at the front end of the extruder, and its purpose is only for physical melting and dispersion. It first uses mechanical force to build a stable functional precursor network "skeleton"; step S2 is carried out in the reaction zone in the middle and downstream of the extruder, and the liquid reactants are injected into the already formed "skeleton" for chemical reaction. This spatial separation and temporal sequence avoids the random reaction or degradation of the highly active grafted precursors in the early stage of melting, and realizes the precise control of "physical positioning first, then chemical bonding", which is the key to distinguishing this process from traditional integrated reactive extrusion. The subsequent steps S3 and S4 are to purify and solidify the reaction products to ensure the quality and performance of the final product.

[0029] Preferably, the temperature of the melt dispersion zone at the front end of the extruder is set to 170-190°C, and the temperature of the reaction zone is set to 190-210°C.

[0030] Furthermore, the temperature gradient setting is based on a comprehensive consideration of physical blending and chemical reaction kinetics. The melt dispersion zone temperature of 170-190°C is sufficient to completely melt the solid components and achieve good physical dispersion, but not enough to trigger large-scale side reactions or polymer degradation. The reaction zone temperature of 190-210°C provides the necessary activation energy for the grafting reaction of isocyanate groups and hydroxyl groups, which can significantly increase the reaction rate and ensure that the grafting reaction can proceed fully within the limited time that the melt flows through this zone.

[0031] Preferably, the first feed port is a main feed port, and the second feed port is a side feed port arranged in the midstream of the extruder.

[0032] Furthermore, the physical configuration of the feed ports provides the hardware foundation for implementing the "zoned, sequential" process logic. The main feed port is used to add large quantities of solid materials that require strong shear for melt dispersion. Side feed ports, located midstream in the extruder, allow for the direct injection of small amounts of highly reactive liquid reactants into the already molten polymer matrix, enabling precise addition of reactants at specific times and locations.

[0033] Preferably, the devolatilization treatment in step S3 is intended to extract the carbon dioxide gas generated by the side reaction between the anti-aging functional grafting precursor and the residual moisture in the system, as well as the anti-aging functional grafting precursor that does not participate in the grafting reaction, from the polymer melt through the vacuum exhaust port.

[0034] Furthermore, the chemical purpose of the devolatilization treatment was clarified. The isocyanate group will not only react with the target hydroxyl group, but also with the inevitable trace moisture in the system to generate unstable carbamic acid, which will quickly decompose into amine and carbon dioxide (CO2) gas. CO2 gas can cause defects such as bubbles and voids in the final film product. At the same time, unreacted, volatile grafting precursor small molecules must also be removed. Therefore, the devolatilization step is a key purification link to remove these gaseous by-products and liquid residues, which is crucial to ensuring the uniformity of the film's appearance and the stability of its inherent performance.

[0035] Preferably, the devolatilization treatment in step S3 is performed through a vacuum exhaust port provided at the rear end of the extruder, and the vacuum degree is -0.08 to -0.095 MPa.

[0036] Furthermore, at high vacuum levels of -0.08 to -0.095 MPa, the saturated vapor pressure of volatile components (such as CO2 and unreacted monomers) on and within the polymer melt is significantly higher than the ambient pressure. This significant pressure differential creates a powerful driving force, forcing these small molecules to overcome the resistance of the viscous melt, rapidly diffuse from the melt, and escape, allowing them to be efficiently removed by the vacuum system. Adopting this vacuum range ensures optimal purification results within a short residence time in the devolatilization zone.

[0037] The present invention provides an anti-aging antistatic film and a production process thereof. It has the following beneficial effects:

[0038] 1. The present invention uses hindered amine molecules with isocyanate groups and polyether carbonate copolymers as reaction precursors. In subsequent processing, the two are grafted in situ to generate a single, bifunctional synergistic polymer additive. This integration at the molecular level brings about a deep synergy of anti-aging and antistatic properties. Compared with the existing solution of physically blending independent anti-aging agents and antistatic agents, the present invention fundamentally solves the "antagonistic effect" caused by chemical incompatibility between additives (such as acid-base neutralization). It avoids the mutual "poisoning" of functional additives in the molten state, ensuring that both core functions can be exerted without loss.

[0039] 2. The present invention uses strong shearing action at the front end of the extruder to build a physical network skeleton of the antistatic functional main chain. Subsequently, the highly active anti-aging grafting precursor is precisely injected into the reaction zone in the middle and downstream of the extruder. This process realizes the decoupling of physical dispersion and chemical reaction in space and time. This non-traditional processing logic has achieved unexpected process effects. Compared with the "one-pot" reaction extrusion in the prior art where all materials are mixed at once, this solution solves the technical problems of premature degradation of reactants in the high shear zone at the front end and uncontrollable reaction sites. It realizes the targeted guidance of the grafting reaction, greatly improving the utilization efficiency of expensive functional groups and the regularity of the final product structure.

[0040] 3. The present invention introduces maleic anhydride grafted polyolefin as a synergistic enhancer in the formula. This component plays an extraordinary dual role in the system. It not only acts as an "interface bridge", but also significantly improves the physical dispersion and interfacial bonding strength of the polar functional network in the non-polar base resin. Even more unexpectedly, it also constructs a new chemical protection mechanism of "energy relay", which can actively capture free radicals in the matrix resin and efficiently transfer them to the hindered amine units on the functional network for quenching. This is completely different from the idea of ​​adding ordinary compatibilizers only to improve compatibility in the prior art. The present invention solves the mechanical defects caused by uneven dispersion of functional additives, and creatively upgrades point-like passive protection to systematic active synergistic protection, greatly expanding the effective protection range of the anti-aging function. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the preparation process of the present invention;

[0042] Figure 2 It is a technical process flow chart of the present invention. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the present specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] Please see the attached Figure 1 -Attached Figure 2 :

[0045] Example 1

[0046] 1. Raw Materials Preparation

[0047] Solid component preparation: Weigh, by weight, the following: 91 parts linear low-density polyethylene (LLDPE), the base resin; 6 parts poly(propylene carbonate)-poly(ethylene oxide) copolymer (PPC-PEO, number-average molecular weight 12,000), the antistatic functional backbone precursor; and 1.8 parts maleic anhydride-grafted polyethylene wax (MAH-g-PEW), the synergist. Dry these three solid components in an 85°C forced-air oven for 4 hours. After drying, place them in a high-speed mixer and mix at 400 rpm for 10 minutes to obtain a uniform solid mixture A.

[0048] Liquid component preparation: Weigh, by weight, 1.1 parts of the anti-aging functional graft precursor 2,2,6,6-tetramethyl-4-isocyanatopiperidine and 0.05 parts of the catalyst dibutyltin dilaurate. Mix the two at room temperature to obtain the liquid reactant B to be injected.

[0049] 2. Reactive extrusion and film formation

[0050] A twin-screw extruder with an L / D ratio of 48 was used. Its screw assembly included a conveying section, a kneading section, a reaction section, and a distributive mixing section. The first section of the screw was set as the main feed port, the sixth section was set as the lateral liquid feed port, and the ninth section was equipped with a vacuum exhaust port.

[0051] Physical Blending and Network Construction: Start the extruder and set the temperatures of each zone from the feed port to the die to 170°C, 180°C, 185°C, 190°C, 200°C, 200°C, 205°C, 200°C, and 195°C, respectively. Zones 2-5 (180°C-200°C) constitute the melt dispersion zone. Feed the prepared solid mixture A steadily into the extruder through the main feed port.

[0052] b) Targeted Injection and In-Situ Reaction: When the melt is stably delivered to Zone 6, liquid reactant B is injected from the side liquid feed port via a precision metering pump. The grafting reaction proceeds in the reaction zone of Zones 6-8 (200°C-205°C).

[0053] Devolatilization: The reacted melt passes through the vacuum vent in Zone 9, where the vacuum is maintained at -0.09 MPa to remove by-products. After homogenization, the melt is extruded from a T-die, cast onto a cooling roll at 30°C, and finally wound to form the desired film.

[0054] Example 2

[0055] 1. Raw Materials Preparation

[0056] Solid component preparation: Weigh, by weight, the following: 97 parts of the base resin LLDPE; 2 parts of the antistatic functional backbone precursor PPC-PEO; and 0.5 parts of the synergist MAH-g-PEW. Dry these three solid components in an 80°C forced air oven for 6 hours. After drying, place them in a high-speed mixer and mix at 300 rpm for 15 minutes to obtain a uniform solid mixture C.

[0057] b) Liquid component preparation: Weigh, by weight, 0.2 parts of the anti-aging functional graft precursor 2,2,6,6-tetramethyl-4-isocyanatopiperidine and 0.01 parts of the catalyst dibutyltin dilaurate. Mix the two components at room temperature to obtain the liquid reactant D to be injected.

[0058] 2. Reactive extrusion and film formation

[0059] The same twin-screw extruder as in Example 1 was used.

[0060] Physical blending and network construction: Start the extruder and set the temperatures of each zone from the feed port to the die to 160°C, 170°C, 175°C, 180°C, 190°C, 190°C, 190°C, 195°C, 190°C, and 185°C, respectively. Zones 2-5 (170°C-190°C) constitute the melt dispersion zone. The prepared solid mixture C is steadily fed into the main feed port.

[0061] Targeted injection and in-situ reaction: When the melt is stably delivered to zone 6, liquid reactant D is injected from the side liquid feed port via a precision metering pump. The material undergoes grafting reaction in the reaction zone of zones 6-8 (190℃-195℃).

[0062] Devolatilization: The reacted melt passes through the vacuum vent in Zone 9, where the vacuum is maintained at -0.08 MPa. After homogenization, the melt is extruded from a T-die, cast onto a cooling roll at 40°C, and finally wound to produce the desired film.

[0063] Example 3

[0064] 1. Raw Materials Preparation

[0065] Solid component preparation: Weigh, by weight, 85 parts of the base resin LLDPE; 10 parts of the antistatic functional backbone precursor PPC-PEO; and 3 parts of the synergist MAH-g-PEW. Dry these three solid components in a 90°C forced air oven for 4 hours. After drying, place them in a high-speed mixer and mix at 500 rpm for 10 minutes to obtain a uniform solid mixture E.

[0066] Liquid component preparation: Weigh by weight: 2 parts of the anti-aging functional graft precursor 2,2,6,6-tetramethyl-4-isocyanatopiperidine and 0.1 parts of the catalyst dibutyltin dilaurate. Mix the two at room temperature to obtain the liquid reactant F to be injected.

[0067] 2. Reactive extrusion and film formation

[0068] The same twin-screw extruder as in Example 1 was used.

[0069] Physical blending and network construction: Start the extruder and set the temperatures of each zone from the feed port to the die to 180°C, 190°C, 190°C, 195°C, 210°C, 210°C, 215°C, 210°C, and 205°C, respectively. Zones 2-5 (190°C-210°C) constitute the melt dispersion zone. The prepared solid mixture E is steadily fed into the main feed port.

[0070] Targeted injection and in-situ reaction: When the melt is stably delivered to zone 6, liquid reactant F is injected from the side liquid feed port via a precision metering pump. The material undergoes grafting reaction in the reaction zone of zones 6-8 (210℃-215℃).

[0071] Devolatilization molding: The reacted melt passes through the vacuum exhaust port of the 9th zone, where the vacuum degree is maintained at -0.095MPa. After homogenization, the melt is extruded from the T-die, cast on a cooling roller at a temperature of 20°C for shaping, and finally wound to obtain the target film.

[0072] Comparative Example 1:

[0073] Compared to Example 1, the difference lies in the use of a traditional physical blending scheme instead of reactive raw materials. Specifically, the antistatic functional backbone precursor (PPC-PEO) and the anti-aging functional graft precursor (2,2,6,6-tetramethyl-4-isocyanatopiperidine) are omitted, and no catalyst is added. Instead, 7.1 parts of a traditional non-reactive polyether antistatic agent (brand PELESTAT-300) and 1.1 parts of a traditional non-reactive hindered amine light stabilizer (brand 944) are used. All materials are added to the extruder at once through the main feed port for blending and extrusion. All other procedures remain the same.

[0074] Comparative Example 2:

[0075] Compared to Example 1, the difference lies in the use of a one-pot reaction extrusion process. Specifically, the liquid reactant B (anti-aging functional graft precursor and catalyst) in Example 1 was pre-mixed with the solid mixture A. All materials were then fed into the extruder at once through the main feed port, without using a side liquid feed port for sequential reaction. All other processes remained the same.

[0076] Comparative Example 3:

[0077] Compared with Example 1, the difference is that no synergist (maleic anhydride grafted polyethylene wax) is added to the formula, and in order to keep the total number of parts unchanged, the amount of base resin LLDPE is increased to 92.8 parts. The rest are the same.

[0078] Comparative Example 4:

[0079] Compared with Example 1, the difference is that the amount of the antistatic functional main chain precursor (PPC-PEO) is reduced to 1 part below the lower limit of the claim, and the amount of the base resin LLDPE is increased to 96 parts accordingly. The rest are the same.

[0080] Comparative Example 5:

[0081] Compared with Example 1, the difference is that the amount of the anti-aging functional graft precursor (2,2,6,6-tetramethyl-4-isocyanate piperidine) is increased to 3 parts, which is higher than the upper limit of the claim, and the amount of the base resin LLDPE is correspondingly reduced to 89.1 parts. The rest are the same.

[0082] Comparative Example 6:

[0083] Compared with Example 1, the difference is that during the reactive extrusion film forming process, the vacuum exhaust port in the 9th zone is closed, that is, the melt after the reaction is not subjected to devolatilization and purification treatment. The rest are the same.

[0084] Test Example 1: Comparative test of antistatic performance and durability

[0085] Experimental procedures

[0086] Sample preparation and conditioning:

[0087] Samples were taken from the film rolls prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 4 and cut into 100 mm x 100 mm square specimens. Ten specimens were prepared for each group. All specimens were conditioned in a constant temperature and humidity chamber at 23 ± 2°C and 50 ± 5% relative humidity for at least 24 hours.

[0088] Initial surface resistivity test:

[0089] Remove the conditioned specimens (5 per group) and test them using a ZC36 megohmmeter. Place the specimen on the instrument's insulation test bench and position the three-electrode test head steadily over the center of the specimen. Apply a 500V DC test voltage for 1 minute. After the voltage stabilizes, read and record the surface resistivity value. Test each group of 5 specimens individually, and calculate the arithmetic mean as the initial surface resistivity for that group.

[0090] Heat aging treatment:

[0091] The remaining samples (5 pieces per group) were hung on a sample rack in a forced air constant temperature oven, ensuring that the samples did not touch each other. The oven temperature was set to 80°C and the heat aging treatment was continued for 168 hours.

[0092] Surface resistivity test after aging:

[0093] After the thermal aging is complete, remove the sample and place it again in a constant temperature and humidity chamber at 23±2°C and 50±5% relative humidity for 24 hours. After conditioning, measure the surface resistivity of the aged sample using the same method as in step 2 and calculate the arithmetic mean.

[0094] Experimental data

[0095] Table 1: Antistatic performance and durability test results

[0096]

[0097] Experimental results analysis and summary

[0098] The data in the above table clearly reveal the significant advantages of the present invention in terms of antistatic performance and its durability. Not only is the initial surface resistivity of the film of Example 1 much lower than that of the comparative examples, but more importantly, after undergoing severe thermal aging, its performance attenuation is extremely small, and the surface resistivity only increases slightly, showing excellent performance stability. This is attributed to the unique technical concept of the present invention, that is, through an in-situ grafting reaction, the antistatic functional segment and the anti-aging functional unit are firmly integrated in the form of chemical bonds on the same polymer. This "locking" at the molecular level completely eliminates the migration of functional additives, and fundamentally avoids the chemical "poisoning" effect caused by the physical coexistence of the acidic antistatic agent and the alkaline hindered amine in Comparative Example 1, thereby ensuring the integrity and long-term effect of the antistatic functional network.

[0099] Comparison of Comparative Example 2 with Example 1 highlights the advanced nature of the present invention's process. Comparative Example 2 employs a "one-pot" mixing process, prematurely exposing the highly reactive isocyanate groups to the high-temperature, high-shear environment at the front end of the extruder. This results in partial degradation and ineffective side reactions, significantly reducing the final grafting efficiency and product regularity. Consequently, its antistatic performance is far inferior to that of Example 1. The present invention utilizes a partitioned sequential reaction process, first constructing a physical network, followed by a targeted injection reaction. This allows for precise control of the chemical reaction process, ensuring efficient utilization of functional groups and providing a prerequisite for achieving superior performance.

[0100] In addition, the results of Comparative Example 4 further confirm the scientific nature of the formulation system of the present invention. Even if the same advanced process is used, due to the insufficient amount of the antistatic functional main chain precursor, a complete and penetrating conductive path cannot be formed in the matrix resin (i.e., the percolation threshold is not reached), resulting in poor initial antistatic performance. This shows that the component range defined by the present invention is a necessary condition for achieving its technical effect. Only when the appropriate component ratio is combined with the advanced preparation process can the expected synergistic effect be exerted to obtain long-term and stable anti-aging and antistatic properties.

[0101] Test Example 2: Accelerated Aging Performance Comparison Test

[0102] Experimental procedures

[0103] Sample preparation:

[0104] Samples were cut longitudinally and transversely from the film rolls prepared in Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 5. A dumbbell-type punching machine was used to prepare Type IV specimens in accordance with the GB / T1040.3-2006 standard, with 10 sheets prepared for each set of samples.

[0105] Initial mechanical properties test:

[0106] Condition the cut specimens (5 per group) at 23±2°C and 50±5% relative humidity for 24 hours. Tensile tests were performed on the specimens using a universal testing machine equipped with a 50N load cell at a rate of 200 mm / min. The maximum tensile strength and elongation at break were recorded. The arithmetic mean of the five specimens was calculated as the initial mechanical properties.

[0107] UV accelerated aging treatment:

[0108] The remaining samples (5 pieces per group) were fixed on the sample rack of the UV accelerated aging test chamber. The aging procedure was set as follows: UVA-340 lamp was used, and the irradiance of the lamp was controlled at 0.89W / (m 2 nm) @ 340 nm. Cycling conditions were: light phase, blackboard temperature 60°C, for 8 hours; dark condensation phase, blackboard temperature 50°C, for 4 hours. All samples were subjected to continuous aging for a total of 500 hours.

[0109] Mechanical properties test after aging:

[0110] After aging, remove the sample from the test chamber and condition it at standard temperature and humidity for 24 hours. Use the same method as step 2 to test the tensile strength of the aged sample.

[0111] Performance retention rate calculation:

[0112] The tensile strength retention rate of each group of samples was calculated according to the formula: tensile strength retention rate (%) = (tensile strength after aging / initial tensile strength) × 100%.

[0113] Experimental data

[0114] Table 2: Accelerated aging performance test results

[0115]

[0116] Experimental results analysis and summary

[0117] The above experimental data strongly prove that the present invention has unparalleled advantages in anti-aging performance. After 500 hours of rigorous UV accelerated aging, the sample of Example 1 has a tensile strength retention rate of up to 88.5%, with very little performance degradation. In sharp contrast, the strength retention rate of Comparative Example 1, which adopts the traditional physical blending scheme, is only 38.9%. The root of this huge difference is that the in-situ grafting reaction of the present invention firmly bonds the basic hindered amine unit to the polymer chain, completely avoiding its direct contact and acid-base neutralization with the acidic antistatic system during the melt processing process, thereby completely retaining the free radical capture activity of the hindered amine and achieving long-lasting and efficient anti-aging protection.

[0118] The process superiority of the present invention is also fully demonstrated in comparison with Comparative Example 2. Comparative Example 2 uses a "one-pot" reaction extrusion method, and its strength retention rate is only 56.2%, which is much lower than that of Example 1. This is because the highly active anti-aging graft precursor is placed in the strong shear heat environment at the front end of the extruder too early, resulting in degradation of the functional groups and ineffective reactions. The resulting bifunctional auxiliary agent has an irregular structure and low efficiency. The partitioned sequential reaction process of the present invention, through the ingenious design of "network construction first, then grafting", provides a mild reaction environment for the reactants, ensures the efficiency and precision of the grafting reaction, and is a key process guarantee for obtaining excellent weather resistance.

[0119] The results of Comparative Examples 3 and 5 reveal the inherent synergistic mechanism of the present invention's formulation. In the absence of the synergist, the performance retention rate of Comparative Example 3 dropped to 72.4%, confirming that maleic anhydride-grafted polyolefin is more than just a simple compatibilizer; the interfacial layer and "energy relay" mechanism it creates are crucial for optimizing the dispersion of functional additives and maximizing their effectiveness. Furthermore, Comparative Example 5, which blindly increases the amount of the anti-aging graft precursor, actually exhibits a slightly lower performance retention rate than Example 1. This demonstrates that the component range defined by the present invention is scientifically optimized, and that excessive amounts of active components do not lead to a linear improvement in performance but may instead trigger side reactions, demonstrating the accuracy and scientific nature of the present invention's formulation.

[0120] Test Example 3: Material uniformity and mechanical properties comparison test

[0121] Experimental procedures

[0122] Sample preparation:

[0123] Samples were cut longitudinally and transversely from the film rolls prepared in Example 1, Comparative Example 3, and Comparative Example 6. A dumbbell punch was used to prepare some of these samples into Type IV specimens in accordance with GB / T 1040.3-2006 for mechanical property testing. Separately, 10 mm x 10 mm square specimens were cut for density testing. Ten specimens were prepared for each sample group.

[0124] Basic mechanical properties test:

[0125] Condition dumbbell-shaped specimens (5 per group) at 23±2°C and 50±5% relative humidity for 24 hours. Perform tensile tests on the specimens using a universal testing machine at a speed of 200 mm / min. Record the tensile strength and elongation at break. Calculate the arithmetic mean and standard deviation of the five specimens.

[0126] Material density test:

[0127] After conditioning square specimens (five per group) under standard conditions for 24 hours, they were tested using an electronic density meter that complies with GB / T1033.1-2008. The specimens were placed sequentially into the test medium (ethanol), and the instrument automatically calculated and read the density of the material. The arithmetic mean of the five specimens was calculated as the density of the group.

[0128] Experimental data

[0129] Table 3: Material uniformity and mechanical properties test results

[0130] Sample name Tensile strength (MPa) Elongation at break (%) <![CDATA[Density (g / cm 3 )]]> Example 1 18.3±0.4 510±15 0.931 Comparative Example 3 16.1±1.5 280±45 0.930 Comparative Example 6 17.9±1.8 350±60 0.915

[0131] Experimental results analysis and summary

[0132] The data in the above table deeply reveal the decisive influence of the formula and process of the present invention on the physical quality of the final product. The comparison results of Comparative Example 3 and Example 1 clearly demonstrate the indispensable key role of the synergist in the system. After the lack of maleic anhydride grafted polyolefin, although the tensile strength of the film of Comparative Example 3 decreased slightly, its elongation at break dropped drastically, and the standard deviation of the mechanical property test results increased significantly. This strongly illustrates that without the synergist as an "interface bridge", there are serious compatibility issues between the polar functional additive network and the non-polar base resin, resulting in microphase separation. These unevenly dispersed fragile interfaces will become stress concentration points when subjected to force, causing the material to break prematurely, thereby seriously damaging the toughness and reliability of the film.

[0133] The data of Comparative Example 6 highlights the rigor and necessity of the process design of the present invention from another dimension. The film density of Comparative Example 6 is significantly lower than that of Example 1, the lowest among all samples. At the same time, its elongation at break is greatly reduced, and the data discreteness is extremely large. This is directly attributed to the omission of the vacuum devolatilization step. The gaseous by-products such as carbon dioxide produced during the in-situ reaction are trapped in the melt, and eventually a large number of microbubbles and physical defects are formed inside the film. These defects not only reduce the apparent density of the material, but also become fatal "holes" that destroy the continuity of the material, making the film extremely easy to tear when stretched, and unable to exhibit the mechanical properties that the material should have.

[0134] In summary, the excellent comprehensive performance obtained by the present invention is the result of the synergistic effect of its complete technical solution. The sample of Example 1 has both high tensile strength and high elongation at break, and has stable performance and normal density, indicating that its internal structure is uniform and dense. This is due to the fact that the synergistic enhancer constructs a stable phase interface at the microscopic level, ensuring the perfect fusion of the functional network and the matrix; at the same time, the vacuum devolatilization step in the partitioned sequential reaction extrusion process ensures the physical purity of the product at the macroscopic level. The two complement each other and are indispensable, and together ensure that the anti-aging and antistatic film of the present invention has advanced functions while also having excellent physical quality and mechanical reliability.

[0135] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An anti-aging antistatic film, wherein the antistatic film is characterized by: Includes the following components: Base resin: 85-97 parts; Antistatic functional main chain precursor: 2-10 parts; Anti-aging functional grafting precursor: 0.2-2 parts; Synergist: 0.5-3 parts; Catalyst: 0.01-0.1 parts.

2. The anti-aging antistatic film according to claim 1, characterized in that: The antistatic functional main chain precursor is a polypropylene carbonate-polyethylene oxide copolymer; and the anti-aging functional graft precursor is a hindered amine compound with a reactive functional group.

3. The anti-aging antistatic film according to claim 1, characterized in that: The hindered amine compound with a reactive functional group is 2,2,6,6-tetramethyl-4-isocyanate piperidine.

4. The anti-aging antistatic film according to claim 1, characterized in that: The synergist is a polar-modified polyolefin.

5. The anti-aging antistatic film according to claim 4, characterized in that: The polar modified polyolefin is maleic anhydride grafted polyethylene wax or maleic anhydride grafted polyolefin elastomer.

6. A process for producing an anti-aging antistatic film, for preparing an anti-aging antistatic film according to claims 1-5, wherein the process is carried out in a twin-screw extruder having at least two independent feed ports, characterized in that: The following steps are involved: Step S1, physical blending and network construction step: adding a mixture of the base resin, the antistatic functional main chain precursor and the synergist from the first feed port of the extruder, and melt blending in the melt dispersion zone at the front end of the extruder to form a physically dispersed functional network structure; Step S2, targeted injection and in-situ reaction step: injecting the anti-aging functional graft precursor and catalyst into the melt formed by the material in step S1 at a second feed port downstream of the extruder, and performing an in-situ grafting reaction in the reaction zone of the extruder to generate a bifunctional polymer additive; Step S3, devolatilization and purification step: devolatilization treatment is performed on the melt after the reaction in step S2 to remove by-products or unreacted substances; Step S4, homogenization and molding step: homogenize the melt after the material treatment in step S3, and extrude it through a die to form a film.

7. The production process of the anti-aging antistatic film according to claim 6, characterized in that: The temperature of the melt dispersion zone at the front end of the extruder is set to 170-190°C, and the temperature of the reaction zone is set to 190-210°C.

8. The production process of the anti-aging antistatic film according to claim 6, characterized in that: The first feed port is a main feed port, and the second feed port is a side feed port arranged in the midstream of the extruder.

9. The production process of the anti-aging antistatic film according to claim 6, characterized in that: The devolatilization treatment in step S3 is intended to extract the carbon dioxide gas generated by the side reaction between the anti-aging functional grafting precursor and the residual moisture in the system, as well as the anti-aging functional grafting precursor that does not participate in the grafting reaction, from the polymer melt through the vacuum exhaust port.

10. The production process of the anti-aging antistatic film according to claim 6, characterized in that: The devolatilization treatment in step S3 is performed through a vacuum exhaust port provided at the rear end of the extruder, with a vacuum degree of -0.08 to -0.095 MPa.

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