High-strength antistatic composite film and method for manufacturing the same

Abstract

The application discloses a kind of high-strength antistatic composite film and preparation method thereof, belong to high polymer material technical field.The antistatic composite film includes the following weight parts components: 80-100 parts high-density polyethylene, 10-25 parts composite antistatic agent, 1-2.5 parts lubricant, 3-5 parts polypropylene graft maleic anhydride, 0.1-1 parts antioxidant, the high-density polyethylene of the application is used as matrix, by blending into composite antistatic agent, without using the mode of external coating, so that the prepared composite film has long-term antistatic effect, not only can significantly improve the surface performance of composite film, but also can guarantee the comprehensive mechanical properties of film and processing adaptability, suitable for a variety of packaging scenarios with higher requirements on surface performance.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a high-strength antistatic composite film and its preparation method. Background Technology

[0002] Antistatic composite films are key materials for safely and effectively dissipating surface static charges and preventing static electricity accumulation. They are widely used in electronic device packaging, aerospace, medical devices, LCD panels, and precision instrument protection. In the electronics industry, static electricity accumulation can lead to component breakdown or signal interference, and traditional packaging materials struggle to simultaneously meet the requirements of high mechanical strength and antistatic properties. Furthermore, in cleanroom environments or flammable and explosive locations, antistatic performance is crucial for safety. Therefore, developing a composite film that combines high strength, durability, and stable antistatic properties has significant industrial value.

[0003] Currently, existing antistatic films are mainly achieved by adding conductive fillers (such as carbon nanotubes, metal particles, or conductive polymers) or coating the surface with antistatic agents. However, these methods have significant drawbacks: uneven dispersion of conductive fillers can lead to unstable antistatic effects; and surface coating methods have poor wear resistance and are prone to failure due to friction or cleaning. Furthermore, some technologies employ multilayer composite structures, but insufficient interlayer bonding can easily lead to delamination, affecting service life. Therefore, there is an urgent need to develop a high-strength antistatic composite film with simple processing and controllable cost to solve the problem of the difficulty in synergistically optimizing mechanical and antistatic properties in existing technologies.

[0004] Chinese patent document CN103435891A discloses an antistatic plastic film and its preparation method. The antistatic plastic film, by weight, comprises: 70-80 parts low-density polyethylene, 0.5-1 parts aluminum hydroxide, 0.5-1 parts coupling agent, 0.5-2 parts lubricant, 0.5-1 parts ethylene glycol laurylamide, 0.5-1 parts antistatic agent HZ-1, 0.2-1 parts antistatic agent UHZ-14, and 0.5-1 parts coupling agent KR-9s. The preparation process includes mixing, extrusion, and winding. The antistatic plastic film provided by this invention has good physical properties and antistatic properties, effectively overcoming electrostatic adsorption problems during application. However, the antistatic agent used in this invention is a small molecule substance, and its antistatic performance not only rapidly decays with time and friction, resulting in poor timeliness, but also the additives continuously precipitated from the material can cause secondary pollution to the packaged precision electronic components. Furthermore, its mechanical properties require further improvement. Summary of the Invention

[0005] The main objective of this invention is to propose a high-strength antistatic composite film and its preparation method. By adding a composite antistatic agent, the antistatic and mechanical properties of the composite film are significantly improved.

[0006] To achieve the above objectives, the present invention proposes a high-strength antistatic composite film comprising the following components by weight: 80-100 parts high-density polyethylene, 10-25 parts composite antistatic agent, 1-2.5 parts lubricant, 3-5 parts polypropylene grafted maleic anhydride, and 0.1-1 parts antioxidant.

[0007] Preferably, the preparation method of the composite antistatic agent includes the following steps:

[0008] (1) Carbon nanotubes were added to an aqueous ethanol solution, and aminosilane coupling agent was added for treatment. The resulting solid product was dispersed in anhydrous ethanol, the pH was adjusted to be weakly acidic, maleic anhydride was added, and the reaction was heated. After the reaction was completed, the product was filtered, washed, and dried to obtain pretreated carbon nanotubes.

[0009] (2) Allyltrimethylammonium chloride and initiator ammonium persulfate were dissolved in water, and then pretreated carbon nanotubes were added. The polymerization reaction was carried out under N2 protection to obtain modified carbon nanotubes.

[0010] (3) The modified carbon nanotubes were dispersed in water, the pH was adjusted to 4-6, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added for activation, and then 2-aminophenylethanol was added. The amidation reaction was carried out under N2 protection. After the reaction was completed, the mixture was filtered, the solid was collected, washed and dried to obtain the composite antistatic agent.

[0011] More preferably, in step (1), the mass ratio of carbon nanotubes, aminosilane coupling agent, and maleic anhydride is 20-30:3-5:4-7; the heating reaction temperature is 50-70℃, and the heating time is 4-6h.

[0012] Carbon nanotubes are a type of conductive nanofiller. Adding carbon nanotubes to composite films can improve their mechanical properties and effectively disperse electrostatic charges to the material surface, reducing the possibility of electrostatic accumulation. In this step, carbon nanotubes are first treated with an aminosilane coupling agent to introduce amino groups onto their surface. Then, maleic anhydride reacts with the amino groups, which can simultaneously introduce carbon-carbon double bonds and active carboxyl groups into the carbon nanotubes, which is beneficial for the next step of the reaction.

[0013] More preferably, in step (2), the mass ratio of allyltrimethylammonium chloride ammonium persulfate to pretreated carbon nanotubes is 1.2-1.5:0.1-0.3:1-2; the polymerization reaction temperature is 60-80℃ and the reaction time is 6-8h.

[0014] In this step, allyltrimethylammonium chloride reacts with the carbon-carbon double bonds on the pretreated carbon nanotubes under the action of ammonium persulfate initiator, thereby fixing the polymerized quaternary ammonium salt on the carbon nanotubes, making it less likely to migrate out during processing. This solves the problem of antistatic agent migration failure and endows the material with long-lasting and stable antistatic properties.

[0015] More preferably, in step (3), the mass ratio of modified carbon nanotubes, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide and 2-aminophenylethanol is 1:0.8-1:0.4-0.5:1-1.3.

[0016] In this step, the carboxyl groups on the modified carbon nanotubes undergo an amidation reaction with the amino groups on 2-aminophenylethanol, thereby fixing 2-aminophenylethanol onto the carbon nanotubes. The hydroxyl groups in the molecule can react with the maleic anhydride grafted onto the polypropylene in the component, which can firmly bind the carbon nanotubes to the polymer matrix, enabling efficient stress transfer. At the same time, the introduction of rigid benzene rings restricts the movement of polymer chain segments, making the entire material more difficult to deform under stress, thereby improving the tensile modulus and flexural modulus of the material and synergistically endowing the composite film with excellent mechanical properties.

[0017] Preferably, the lubricant comprises at least one of polyethylene wax, stearic acid, stearate, stearamide, ethylene bis-stearamide, oleamide, erucamide, glyceryl trihydroxystearate, oxidized polyethylene wax, and pentaerythritol stearate.

[0018] Preferably, the antioxidant is at least one selected from 2,6-di-tert-butyl-p-cresol, (2,4-di-tert-butylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, and dioctadecyl pentaerythritol diphosphite.

[0019] This invention also discloses a method for preparing the above-mentioned high-strength antistatic composite film, comprising the following steps:

[0020] Weigh each raw material according to the weight proportions, add the composite antistatic agent, lubricant, polypropylene grafted maleic anhydride and antioxidant into the mixer, mix evenly to obtain a premix, then add the premix and high-density polyethylene together into a twin-screw extruder for melt extrusion, then blow film and shape it with a die head, and after traction cutting and winding, obtain a high-strength antistatic composite film.

[0021] Preferably, the extruder has a rotational speed of 80-150 r / min and a melting temperature of 180-200℃.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1) This invention provides a high-strength antistatic composite film and its preparation method. High-density polyethylene is used as the matrix, and a composite antistatic agent is added by blending. Without external coating, the prepared composite film has a long-lasting antistatic effect. It can not only significantly improve the surface properties of the composite film, but also ensure the comprehensive mechanical properties and processing adaptability of the film. It is suitable for a variety of packaging scenarios with high surface performance requirements.

[0024] 2) This invention significantly improves the antistatic and mechanical properties of a high-strength antistatic composite membrane by adding a composite antistatic agent to the formulation. The preparation process begins by introducing active amino groups onto the surface, which react with maleic anhydride, thereby introducing carbon-carbon double bonds and carboxyl groups. Then, the cationic compound allyltrimethylammonium chloride polymerizes with the carbon-carbon double bonds, fixing the antistatic quaternary ammonium salt onto the carbon nanotubes with stable covalent bonds. This solves the problems of easy migration, easy elution, and time-dependent decay of the antistatic effect of traditional small-molecule antistatic agents. Finally, 2-aminophenylethanol is introduced into the molecule. The hydroxyl groups in this molecule react with the maleic anhydride grafted onto the polypropylene in the component, firmly bonding the carbon nanotubes to the polymer matrix, enabling efficient stress transfer. Simultaneously, the introduction of rigid benzene rings restricts the movement of polymer chain segments, making the entire material more difficult to deform under stress, thus improving the tensile and flexural moduli and synergistically endowing the composite membrane with excellent mechanical properties. Detailed Implementation

[0025] To avoid unnecessary details, unless otherwise specified, all items used in the following examples are commercially available products, and all methods used are conventional methods unless otherwise specified.

[0026] The sources of some of the raw materials used in this invention are as follows:

[0027] High-density polyethylene with a melt flow rate of 7 g / 10 min, branded by Sinopec Fujian Refining Co., Ltd., grade DMDA8008, purchased from Guangdong Xinhao Plastics Co., Ltd.

[0028] Carbon nanotubes, single-armed, with a diameter of 1-2 nm and a length of 5-30 μm, were purchased from Zhongke Leiming (Beijing) Technology Co., Ltd.

[0029] Example 1

[0030] A method for preparing a high-strength antistatic composite film includes the following steps:

[0031] 18g of composite antistatic agent, 2g of polyethylene wax, 4g of polypropylene grafted maleic anhydride and 0.5g of tris(2,4-di-tert-butylphenyl) phosphite were added to a mixer and mixed evenly to obtain a premix. The premix was then added together with 90g of high-density polyethylene to a twin-screw extruder for melt extrusion at a speed of 100r / min and a melt temperature of 190℃. After that, the film was blown and shaped by the die head, and then cut and wound up to obtain a high-strength antistatic composite film.

[0032] The preparation method of the composite antistatic agent includes the following steps:

[0033] (1) 24.8g of carbon nanotubes were added to 300mL of 50wt% ethanol aqueous solution, 4.2g of KH550 was added, the reaction was heated at 40℃ for 3h, and then filtered. The solid was collected, washed and dried, and then dispersed in anhydrous ethanol. The pH value was adjusted to 5, 6g of maleic anhydride was added, and then the reaction was heated at 60℃ for 5h. After the reaction was completed, the solid product was collected by filtration, washed and dried to obtain pretreated carbon nanotubes.

[0034] (2) Dissolve 14g allyltrimethylammonium chloride and 2g initiator ammonium persulfate in 200mL of water, then add 15g of pretreated carbon nanotubes, and carry out polymerization reaction at 70℃ for 7h under N2 protection. After the reaction is completed, filter and collect the solid product, wash and dry it to obtain modified carbon nanotubes.

[0035] (3) Disperse 10g of modified carbon nanotubes in 200mL of water, adjust the pH to 5, add 9g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 4.5g of N-hydroxysuccinimide, stir at 40℃ for 1h, then add 12g of 2-aminophenylethanol, react at 50℃ for 4.5h under N2 protection, filter and collect the solid product, wash and dry to obtain the composite antistatic agent.

[0036] Example 2

[0037] A method for preparing a high-strength antistatic composite film includes the following steps:

[0038] 10g of composite antistatic agent, 1g of polyethylene wax, 3g of polypropylene grafted maleic anhydride and 0.1g of 2,6-di-tert-butyl-p-cresol were added to a mixer and mixed evenly to obtain a premix. The premix was then added together with 80g of high-density polyethylene to a twin-screw extruder for melt extrusion. The extruder speed was 80r / min and the melt temperature was 180℃. After that, the film was blown and shaped by the die head, and then cut and wound up to obtain a high-strength antistatic composite film.

[0039] The preparation method of the composite antistatic agent includes the following steps:

[0040] (1) 20g of carbon nanotubes were added to 300mL of 50wt% ethanol aqueous solution, 3g of KH550 was added, the reaction was heated at 40℃ for 3h, and then filtered. The solid was collected, washed and dried, and then dispersed in anhydrous ethanol. The pH value was adjusted to 5, 4g of maleic anhydride was added, and then the reaction was heated at 50℃ for 6h. After the reaction was completed, the pretreated carbon nanotubes were obtained by filtration, washing and drying.

[0041] (2) Dissolve 12g allyltrimethylammonium chloride and 1g initiator ammonium persulfate in 200mL of water, then add 10g of pretreated carbon nanotubes, and carry out polymerization reaction at 60℃ for 8h under N2 protection. After the reaction is completed, filter and collect the solid product, wash and dry it to obtain modified carbon nanotubes.

[0042] (3) Disperse 10g of modified carbon nanotubes in 200mL of water, adjust the pH to 5, add 8g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 4g of N-hydroxysuccinimide, stir at 40℃ for 1h, then add 10g of 2-aminophenylethanol, and react at 50℃ for 4.5h under N2 protection. Filter, collect the solid product, wash and dry to obtain the composite antistatic agent.

[0043] Example 3

[0044] A method for preparing a high-strength antistatic composite film includes the following steps:

[0045] 25g of composite antistatic agent, 2.5g of polyethylene wax, 5g of polypropylene grafted maleic anhydride and 1g of (2,4-di-tert-butylphenyl) phosphite were added to a mixer and mixed evenly to obtain a premix. The premix was then added together with 100g of high-density polyethylene to a twin-screw extruder for melt extrusion at a speed of 150r / min and a melt temperature of 200℃. After that, the film was blown and shaped by the die, and then cut and wound up to obtain a high-strength antistatic composite film.

[0046] The preparation method of the composite antistatic agent includes the following steps:

[0047] (1) Add 30g of carbon nanotubes to 300mL of 50wt% ethanol aqueous solution, add 5g of KH550, heat at 40℃ for 3h, filter, collect the solid, wash and dry, then disperse in anhydrous ethanol, adjust the pH to 5, add 7g of maleic anhydride, and then heat at 70℃ for 4h. After the reaction is completed, filter, wash and dry to obtain pretreated carbon nanotubes.

[0048] (2) Dissolve 15g allyltrimethylammonium chloride and 3g initiator ammonium persulfate in 200mL of water, then add 20g of pretreated carbon nanotubes, and carry out polymerization reaction at 80℃ for 6h under N2 protection. After the reaction is completed, filter and collect the solid product, wash and dry it to obtain modified carbon nanotubes.

[0049] (3) Disperse 10g of modified carbon nanotubes in 200mL of water, adjust the pH to 5, add 10g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 5g of N-hydroxysuccinimide, stir at 40℃ for 1h, then add 12g of 2-aminophenylethanol, and react at 50℃ for 4.5h under N2 protection. Filter, collect the solid product, wash and dry to obtain the composite antistatic agent.

[0050] Comparative Example 1

[0051] A method for preparing a high-strength antistatic composite film includes the following steps:

[0052] 18g of composite antistatic agent, 2g of polyethylene wax, 4g of polypropylene grafted maleic anhydride and 0.5g of tris(2,4-di-tert-butylphenyl) phosphite were added to a mixer and mixed evenly to obtain a premix. The premix was then added together with 90g of high-density polyethylene to a twin-screw extruder for melt extrusion at a speed of 100r / min and a melt temperature of 190℃. After that, the film was blown and shaped by the die head, and then cut and wound up to obtain a high-strength antistatic composite film.

[0053] The preparation method of the composite antistatic agent is similar to that of Example 1, except that xylitol is not added, and specifically includes the following steps:

[0054] (1) 24.8g of carbon nanotubes were added to 300mL of 50wt% ethanol aqueous solution, 4.2g of KH550 was added, the reaction was heated at 40℃ for 3h, and then filtered. The solid was collected, washed and dried, and then dispersed in anhydrous ethanol. The pH value was adjusted to 5, 6g of maleic anhydride was added, and then the reaction was heated at 60℃ for 5h. After the reaction was completed, the solid product was collected by filtration, washed and dried to obtain pretreated carbon nanotubes.

[0055] (2) Dissolve 14g allyltrimethylammonium chloride and 2g initiator ammonium persulfate in 200mL of water, then add 15g of pretreated carbon nanotubes, and carry out polymerization reaction at 70℃ for 7h under N2 protection. After the reaction is completed, filter and collect the solid product, wash and dry it to obtain the composite antistatic agent.

[0056] Comparative Example 2

[0057] A method for preparing a high-strength antistatic composite film is similar to that in Example 1, except that allyltrimethylammonium chloride is not added. Specifically, it includes the following steps:

[0058] 18g of composite antistatic agent, 2g of polyethylene wax, 4g of polypropylene grafted maleic anhydride and 0.5g of tris(2,4-di-tert-butylphenyl) phosphite were added to a mixer and mixed evenly to obtain a premix. The premix was then added together with 90g of high-density polyethylene to a twin-screw extruder for melt extrusion at a speed of 100r / min and a melt temperature of 190℃. After that, the film was blown and shaped by the die head, and then cut and wound up to obtain a high-strength antistatic composite film.

[0059] The preparation method of the composite antistatic agent includes the following steps:

[0060] (1) 24.8g of carbon nanotubes were added to 300mL of 50wt% ethanol aqueous solution, 4.2g of KH550 was added, the reaction was heated at 40℃ for 3h, and then filtered. The solid was collected, washed and dried, and then dispersed in anhydrous ethanol. The pH value was adjusted to 5, 6g of maleic anhydride was added, and then the reaction was heated at 60℃ for 5h. After the reaction was completed, the solid product was collected by filtration, washed and dried to obtain pretreated carbon nanotubes.

[0061] (2) Disperse 10g of pretreated carbon nanotubes in 200mL of water, adjust the pH to 5, add 9g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 4.5g of N-hydroxysuccinimide, stir at 40℃ for 1h, then add 12g of 2-aminophenylethanol, react at 50℃ for 4.5h under N2 protection, filter and collect the solid product, wash and dry to obtain the composite antistatic agent.

[0062] Comparative Example 3

[0063] A method for preparing a high-strength antistatic composite film includes the following steps:

[0064] 18g of composite antistatic agent, 2g of polyethylene wax, 4g of polypropylene grafted maleic anhydride and 0.5g of tris(2,4-di-tert-butylphenyl) phosphite were added to a mixer and mixed evenly to obtain a premix. The premix was then added together with 90g of high-density polyethylene to a twin-screw extruder for melt extrusion at a speed of 100r / min and a melt temperature of 190℃. After that, the film was blown and shaped by the die head, and then cut and wound up to obtain a high-strength antistatic composite film.

[0065] The preparation method of the composite antistatic agent is similar to that in Example 1, except that allyltrimethylammonium chloride is physically mixed, specifically including the following steps:

[0066] (1) 24.8g of carbon nanotubes were added to 300mL of 50wt% ethanol aqueous solution, 4.2g of KH550 was added, the reaction was heated at 40℃ for 3h, and then filtered. The solid was collected, washed and dried, and then dispersed in anhydrous ethanol. The pH value was adjusted to 5, 6g of maleic anhydride was added, and then the reaction was heated at 60℃ for 5h. After the reaction was completed, the solid product was collected by filtration, washed and dried to obtain pretreated carbon nanotubes.

[0067] (2) Mix 14g of allyltrimethylammonium chloride and 15g of pretreated carbon nanotubes evenly to obtain modified carbon nanotubes.

[0068] Performance testing

[0069] The high-strength antistatic composite film samples prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance testing. Mechanical properties were tested using a universal testing machine according to GB / T1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets". Volume resistivity was tested according to GB / T31838.2-2019 "Dielectric and resistive properties of solid insulating materials - Part 2: Resistive properties (DC method) - Volume resistivity and volume resistivity". The test results are shown in Table 1.

[0070] Table 1. Performance test results of high-strength antistatic composite film

[0071]

[0072] As can be seen from the experimental results in Table 1, the high-strength antistatic composite film obtained in this application has good mechanical strength and antistatic properties.

[0073] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. A high-strength antistatic composite film, characterized in that, It includes the following components by weight: 80-100 parts high-density polyethylene, 10-25 parts composite antistatic agent, 1-2.5 parts lubricant, 3-5 parts polypropylene grafted maleic anhydride, and 0.1-1 parts antioxidant. The preparation method of the composite antistatic agent includes the following steps: (1) Carbon nanotubes were added to an aqueous ethanol solution, and aminosilane coupling agent was added for treatment. The resulting solid product was dispersed in anhydrous ethanol, the pH was adjusted to be weakly acidic, maleic anhydride was added, and the reaction was heated. After the reaction was completed, the product was filtered, washed, and dried to obtain pretreated carbon nanotubes. (2) Allyltrimethylammonium chloride and initiator ammonium persulfate were dissolved in water, and then pretreated carbon nanotubes were added. The polymerization reaction was carried out under N2 protection to obtain modified carbon nanotubes. (3) Disperse the modified carbon nanotubes in water, adjust the pH value to 4-6, add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide for activation, then add 2-aminophenylethanol, carry out amidation reaction under N2 protection, filter after the reaction is complete, collect the solid, wash and dry to obtain composite antistatic agent. In step (1), the mass ratio of carbon nanotubes, aminosilane coupling agent, and maleic anhydride is 20-30:3-5:4-7. In step (2), the mass ratio of allyltrimethylammonium chloride, ammonium persulfate, and pretreated carbon nanotubes is 1.2-1.5:0.1-0.3:1-2. In step (3), the mass ratio of modified carbon nanotubes, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide and 2-aminophenylethanol is 1:0.8-1:0.4-0.5:1-1.

3.

2. The high-strength antistatic composite film according to claim 1, characterized in that: The polymerization reaction temperature is 60-80℃, and the reaction time is 6-8h.

3. The high-strength antistatic composite film according to claim 1, characterized in that: The lubricant includes at least one of polyethylene wax, stearic acid, stearate, stearamide, ethylene bis-stearamide, oleamide, erucamide, glyceryl trihydroxystearate, oxidized polyethylene wax, and pentaerythritol stearate.

4. The high-strength antistatic composite film according to claim 1, characterized in that: The antioxidant is at least one of 2,6-di-tert-butyl-p-cresol, (2,4-di-tert-butylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, and dioctadecyl pentaerythritol diphosphite.

5. A method for preparing a high-strength antistatic composite film according to any one of claims 1-4, characterized in that, The process includes the following steps: weigh each raw material according to the weight proportions, add the composite antistatic agent, lubricant, polypropylene grafted maleic anhydride and antioxidant into a mixer, mix evenly to obtain a premix, then add the premix and high-density polyethylene together into a twin-screw extruder for melt extrusion, then blow film and shape it with a die head, and after traction cutting and winding, obtain a high-strength antistatic composite film.

6. The preparation method according to claim 5, characterized in that: The extruder has a rotation speed of 80-150 r / min and a melt temperature of 180-200℃.

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