Antistatic plastic film and preparation method thereof

Abstract

The invention relates to an antistatic plastic film and a preparation method thereof, and belongs to the technical field of polymeric membrane materials, the antistatic plastic film is composed of a PET base film and an antistatic coating formed by curing an antistatic coating, the antistatic coating comprises the following components in parts by weight: 100 parts of organic silicon resin, 12-18 parts of an antistatic agent, 0.8-1.1 parts of a dispersing agent, 0.4-0.6 part of a bridging agent, 0.15-0.2 part of a flatting agent and 55-60 parts of a solvent, according to the antistatic agent, lamellar graphene is used as an electrostatic charge release matrix, a silane coupling agent KH-550 is used for introducing amino to the surface of a lamellar layer for modification, methyl chloroacetate and the amino grafted to the lamellar layer are used for substitution, finally, methyl iodide and a substituted amine compound are subjected to quaternization reaction, quaternary ammonium cations are introduced to the surface of the graphene lamellar layer, and the antistatic agent is obtained. And a continuous current collecting layer is formed in the coating, so that the generated electrostatic charge is timely led out, and the film material is endowed with excellent antistatic property.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer film materials, and in particular relates to an antistatic plastic film and a preparation method thereof. Background Art

[0002] Polyethylene terephthalate (PET) film has the advantages of excellent mechanical strength, heat resistance, chemical resistance and easy processing, and is widely used in various fields, such as packaging, electronics, and medical treatment. However, the molecular characteristics of PET determine its poor electrical conductivity, and it is easy to carry static electricity during processing and use, which greatly limits the application of PET film materials.

[0003] The so-called static electricity is widely present in people's production and life. Objects are electrically neutral under normal conditions. Due to the different binding forces of different materials on positive and negative charges, electrons will be transferred from one object to another through the interface of the material during contact, friction and separation, causing one object to have excess negative charge and the other object to have insufficient negative charge. PET film materials that generate static electricity will cause static electricity adsorption and static electricity discharge. Static electricity adsorption will bring many inconveniences in production, such as heat sealing and difficulties, pollution of electronic devices, etc. If the charge is large, the electric field exceeds the breakdown voltage of the medium, which will cause static electricity discharge. Static electricity discharge is a huge safety hazard and will cause the breakdown of electronic products and ignite explosives.

[0004] In order to solve the problem of static electricity accumulation in PET film, the current technical means are mainly to compound antistatic agents, and to form a conductive path in the PET matrix by adding conductive materials to the PET film material, so as to guide the generated static electricity and reduce the accumulation of static electricity. Common antistatic materials are divided into the following categories: the first category is ionic antistatic agents, which mainly form anions / cations with charge transfer effects in the matrix, such as quaternary ammonium salts. The charge transfer of such antistatic agents is limited, and it is difficult to form a long-range stable charge transfer channel; the second category is conductive materials, mainly including conductive polymers, conductive metal materials and conductive non-metallic materials, such as polyaniline, silver powder, graphene, carbon black, etc. Such antistatic agents have strong conductivity themselves, but these conductive materials have poor dispersibility in PET, and generally need to be added in large quantities to form a conductive channel. The use of surface treatment technology can improve the compatibility and dispersibility to a certain extent, but these surface treatment materials are filled between adjacent conductive materials to form partitions, which greatly reduces the conductivity, making it difficult to effectively improve the antistatic properties of PET film materials. Summary of the invention

[0005] In order to solve the technical problems mentioned in the background technology, the object of the present invention is to provide an antistatic plastic film and a preparation method thereof.

[0006] The purpose of the present invention can be achieved through the following technical solutions: An antistatic plastic film is composed of a PET base film and an antistatic coating formed by curing an antistatic coating. The antistatic coating comprises, by weight, 100 parts of an organic silicone resin, 12-18 parts of an antistatic agent, 0.8-1.1 parts of a dispersant, 0.4-0.6 parts of a bridging agent, 0.15-0.2 parts of a leveling agent and 55-60 parts of a solvent.

[0007] The antistatic agent is prepared by the following method: Step A1: Mix the silane coupling agent KH-550 and the ethanol solution, adjust the pH value to 3-4 with acetic acid, add graphene oxide and disperse by ultrasonication, stir for 1-1.5 hours, neutralize with sodium hydroxide, stand for 24 hours, wash the bottom precipitate, and dry it under nitrogen protection to obtain a modified matrix; Furthermore, the amount ratio of graphene oxide, silane coupling agent KH-550 and ethanol solution is 10 g: 1.5-2.2 mL: 25-35 mL, the silane coupling agent KH-550 is hydrolyzed under acidic conditions, and then condensed with hydroxyl groups on the surface of graphene oxide to introduce amino modification to the surface of the graphene oxide sheet; Furthermore, the sheet diameter of graphene oxide is not greater than 5 μm, in which case it is easy to form a continuous and stable current collecting layer in the coating.

[0008] Step A2: Mix the modified substrate, methyl chloroacetate and acetone, raise the temperature to 40-50°C, apply stirring at 180-240 rpm, add sodium hydroxide intermittently to react for 6-8 hours, and remove acetone under reduced pressure after the reaction. Wash the substrate and vacuum dry it to obtain an intermediate; Furthermore, the usage ratio of the modified substrate, methyl chloroacetate, sodium hydroxide and acetone is 10 g: 1.2-1.8 mL: 0.15-0.2 g: 40-50 mL, and under the promotion of sodium hydroxide, methyl chloroacetate replaces the amino groups on the surface of the modified substrate.

[0009] Step A3: ultrasonically disperse the intermediate and anhydrous tetrahydrofuran, introduce dry nitrogen for protection, control the temperature of the water bath at 35-40°C, apply stirring at 40-60 rpm, slowly add iodomethane to react for 12-15 hours, and remove tetrahydrofuran by rotary evaporation after the reaction to obtain an antistatic agent; Furthermore, the usage ratio of the intermediate, iodomethane and anhydrous tetrahydrofuran is 10g:0.8-1.2mL:15-20mL. Iodomethane is a strong alkylating agent, which reacts with the amine compound substituted on the surface of the intermediate to undergo quaternary ammonium reaction, thereby introducing quaternary ammonium cations onto the surface of the graphene sheet.

[0010] A method for preparing an antistatic plastic film comprises the following steps: Step S1: premixing an antistatic agent, a dispersant, a bridging agent, a leveling agent and a solvent, and then adding an organic silicone resin and mixing well to obtain an antistatic coating; Step S2: Scrape the antistatic coating onto the surface of the PET base film, send it into a tunnel oven for drying and forming, to form an antistatic coating, and then calender, cut and roll it in sequence to obtain an antistatic plastic film.

[0011] Preferably, the thickness of the antistatic coating is 10% of the thickness of the PET base film. In this state, the two are stably composited and have a good antistatic effect.

[0012] Preferably, the process parameters for drying and molding are set as follows: the drying temperature of zone 1 is 55-65°C, and the drying time is 60-80s; the drying temperature of zone 2 is 70-80°C, and the drying time is 25-35s; the drying temperature of zone 3 is 60-70°C, and the drying time is 20-30s; the drying temperature of zone 4 is 40-50°C, and the drying time is 40-60s.

[0013] Beneficial effects of the present invention: The invention discloses a composite antistatic film material. An antistatic coating is attached to the surface of a traditional PET base film by an external addition method, so as to give the PET base film an excellent antistatic effect. The antistatic coating uses an organic silicone resin as a film-forming material and is compounded with an independently developed antistatic agent. The antistatic coating uses a lamellar graphene as a static charge release matrix, and a silane coupling agent KH-550 is used to introduce amino groups to modify the lamellar surface. Methyl chloroacetate is then used to replace the amino groups grafted on the lamellar layer, and a methyl ester structure is introduced for modification. Finally, methyl iodide is used to react with the substituted amine compound for quaternization. The invention introduces quaternary ammonium cations into the surface of the graphene sheet layer; compared with the traditional externally added antistatic film material, in the coating and curing process of the antistatic coating, the methyl ester structure of the surface layer of the antistatic agent has better affinity and compatibility with the PET base film, and is easy to be attached to the surface of the PET base film to form an enriched layer overlapped by graphene sheets, and the quaternary ammonium cations between adjacent graphene sheets increase the charge conductivity, form a bridging effect, connect the graphene enriched layers into a continuous current collecting layer, and then timely conduct the generated static charge, thereby giving the film material excellent antistatic properties. DETAILED DESCRIPTION

[0014] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0015] Example 1, preparation of antistatic plastic film, the specific implementation process is as follows: (1) Preparation of antistatic agent Step A1: Mix the silane coupling agent KH-550 and a 30% ethanol solution by volume, adjust the pH value to 3 with acetic acid, add graphene oxide and disperse it by ultrasonication, stir for 1 hour, neutralize it with sodium hydroxide, let it stand for 24 hours, wash the bottom precipitate, and dry it under nitrogen protection to obtain a modified matrix, wherein the flake diameter of the graphene oxide is 0.5-3 μm, and the amount ratio of graphene oxide, silane coupling agent KH-550 and ethanol solution is 10 g: 2.2 mL: 35 mL.

[0016] Step A2: Take the modified substrate, methyl chloroacetate and acetone, mix them, heat them to 50°C, stir them at 240rpm, take sodium hydroxide and divide it into four parts, add them intermittently for 30 minutes, continue to stir and react at a constant temperature after complete addition, and control the total reaction time of sodium hydroxide addition to be 6 hours. After the reaction is completed, remove acetone under reduced pressure, wash the substrate and vacuum dry it to obtain an intermediate, wherein the amount ratio of the modified substrate, methyl chloroacetate, sodium hydroxide and acetone is 10g:1.8mL:0.2g:50mL.

[0017] Step A3: ultrasonically disperse the intermediate and anhydrous tetrahydrofuran, introduce dry nitrogen protection, control the temperature of the water bath to 40°C, apply 60rpm stirring, slowly add iodomethane, the addition time is 2h, continue to stir at a constant temperature after complete addition, control the total reaction time of iodomethane addition to be 12h, and remove tetrahydrofuran by rotary evaporation after the reaction is completed to obtain an antistatic agent, wherein the amount ratio of the intermediate, iodomethane and anhydrous tetrahydrofuran is 10g:1.2mL:20mL.

[0018] (2) Preparation of antistatic plastic film Step S1: taking raw materials according to weight parts, 100 parts of silicone resin, SYL-OFF™ SB7458 raw material is used in the implementation process; 12 parts of antistatic agent, which is self-made in this embodiment; 0.8 parts of dispersant, Silok® 7145 raw material is used in the implementation process; 0.4 parts of bridging agent, SYL-OFF™ 7672 raw material is used in the implementation process; 0.15 parts of leveling agent, TEGO® Glide 410 raw material is used in the implementation process; 55 parts of solvent, industrial grade ethyl acetate is used in the implementation process; The antistatic agent, dispersant, bridging agent, leveling agent and solvent were added into a stirrer and premixed at 300 rpm for 10 min, and then the silicone resin was added and mixed at 30 rpm for 30 min to obtain an antistatic coating.

[0019] Step S2: applying the antistatic coating to the surface of the cast PET base film, sending it into a tunnel oven for drying and forming, the antistatic coating is cured on the surface of the PET base film to form an antistatic coating, the thickness of the antistatic coating is controlled to be 10% of the thickness of the PET base film, and then calendering, cutting, and winding are performed in sequence to obtain an antistatic plastic film; wherein, the process parameters for drying and forming are set as follows: the drying temperature of the first zone is 65°C, and the drying time is 60s; the drying temperature of the second zone is 80°C, and the drying time is 25s; the drying temperature of the third zone is 70°C, and the drying time is 20s; the drying temperature of the fourth zone is 50°C, and the drying time is 40s.

[0020] Example 2, preparation of antistatic plastic film, the specific implementation process is as follows: (1) Preparation of antistatic agent Step A1: Mix the silane coupling agent KH-550 and a 30% ethanol solution by volume, adjust the pH value to 4 with acetic acid, add graphene oxide and disperse it by ultrasonication, stir for 1.5 hours, neutralize it with sodium hydroxide, let it stand for 24 hours, wash the bottom precipitate, and dry it under nitrogen protection to obtain a modified matrix, wherein the flake diameter of the graphene oxide is 0.5-3 μm, and the amount ratio of graphene oxide, silane coupling agent KH-550 and ethanol solution is 10 g: 1.5 mL: 25 mL.

[0021] Step A2: Take the modified substrate, methyl chloroacetate and acetone, mix them, heat to 40°C, apply stirring at 180rpm, take sodium hydroxide and divide it into four parts, add it intermittently for 30 minutes, continue to stir the reaction at a constant temperature after complete addition, and control the total reaction time of sodium hydroxide addition to be 8 hours. After the reaction is completed, the acetone is removed under reduced pressure, the substrate is washed and vacuum dried to obtain an intermediate, wherein the amount ratio of the modified substrate, methyl chloroacetate, sodium hydroxide and acetone is 10g:1.2mL:0.15g:40mL.

[0022] Step A3: ultrasonically disperse the intermediate and anhydrous tetrahydrofuran, introduce dry nitrogen for protection, control the temperature of the water bath to 35°C, apply stirring at 40rpm, slowly add iodomethane, the addition time is 3h, continue to stir at a constant temperature after complete addition, control the total reaction time of iodomethane addition to be 15h, and remove tetrahydrofuran by rotary evaporation after the reaction is completed to obtain an antistatic agent, wherein the amount ratio of the intermediate, iodomethane and anhydrous tetrahydrofuran is 10g:0.8mL:15mL.

[0023] (2) Preparation of antistatic plastic film Step S1: taking raw materials according to weight parts, 100 parts of silicone resin, SYL-OFF™ SB7458 raw material is used in the implementation process; 18 parts of antistatic agent, which is self-made in this embodiment; 1.1 parts of dispersant, Silok® 7145 raw material is used in the implementation process; 0.6 parts of bridging agent, SYL-OFF™ 7672 raw material is used in the implementation process; 0.2 parts of leveling agent, TEGO® Glide 410 raw material is used in the implementation process; 60 parts of solvent, industrial grade ethyl acetate is used in the implementation process; The antistatic agent, dispersant, bridging agent, leveling agent and solvent were added into a stirrer and premixed at 300 rpm for 10 min, and then the silicone resin was added and mixed at 30 rpm for 30 min to obtain an antistatic coating.

[0024] Step S2: applying the antistatic coating to the surface of the cast PET base film, sending it into a tunnel oven for drying and forming, the antistatic coating is cured on the surface of the PET base film to form an antistatic coating, the thickness of the antistatic coating is controlled to be 10% of the thickness of the PET base film, and then calendering, cutting and winding are carried out in sequence to obtain an antistatic plastic film; wherein, the process parameters for drying and forming are set as follows: the drying temperature of zone 1 is 55°C, and the drying time is 80s; the drying temperature of zone 2 is 70°C, and the drying time is 35s; the drying temperature of zone 3 is 60°C, and the drying time is 30s; the drying temperature of zone 4 is 40°C, and the drying time is 60s.

[0025] Example 3, preparation of antistatic plastic film, the specific implementation process is as follows: (1) Preparation of antistatic agent Step A1: Mix the silane coupling agent KH-550 and a 30% ethanol solution by volume, adjust the pH value to 3 with acetic acid, add graphene oxide and disperse it by ultrasonication, stir for 1.2 hours, neutralize it with sodium hydroxide, let it stand for 24 hours, wash the bottom precipitate, and dry it under nitrogen protection to obtain a modified matrix, wherein the flake diameter of graphene oxide is 0.5-3 μm, and the amount ratio of graphene oxide, silane coupling agent KH-550 and ethanol solution is 10 g:1.8 mL:30 mL.

[0026] Step A2: Take the modified substrate, methyl chloroacetate and acetone, mix them, heat them to 45°C, stir them at 240rpm, take sodium hydroxide and divide it into four parts, add them intermittently for 30 minutes, continue to stir and react at a constant temperature after complete addition, and control the total reaction time of sodium hydroxide addition to be 7 hours. After the reaction is completed, remove acetone under reduced pressure, wash the substrate and vacuum dry it to obtain an intermediate, wherein the amount ratio of the modified substrate, methyl chloroacetate, sodium hydroxide and acetone is 10g:1.5mL:0.18g:45mL.

[0027] Step A3: ultrasonically disperse the intermediate and anhydrous tetrahydrofuran, introduce dry nitrogen for protection, control the temperature of the water bath to 40°C, apply stirring at 60rpm, slowly add iodomethane, the addition time is 2.2h, continue to stir at constant temperature after complete addition, control the total reaction time of iodomethane addition to be 13h, and remove tetrahydrofuran by rotary evaporation after the reaction is completed to obtain an antistatic agent, wherein the amount ratio of the intermediate, iodomethane and anhydrous tetrahydrofuran is 10g:1.1mL:20mL.

[0028] (2) Preparation of antistatic plastic film Step S1: taking raw materials according to weight parts, 100 parts of silicone resin, SYL-OFF™ SB7458 raw material is used in the implementation process; 16 parts of antistatic agent, which is self-made in this embodiment; 1 part of dispersant, Silok® 7145 raw material is used in the implementation process; 0.5 parts of bridging agent, SYL-OFF™ 7672 raw material is used in the implementation process; 0.18 parts of leveling agent, TEGO® Glide 410 raw material is used in the implementation process; 57 parts of solvent, industrial grade ethyl acetate is used in the implementation process; The antistatic agent, dispersant, bridging agent, leveling agent and solvent were added into a stirrer and premixed at 300 rpm for 10 min, and then the silicone resin was added and mixed at 30 rpm for 30 min to obtain an antistatic coating.

[0029] Step S2: applying the antistatic coating to the surface of the cast PET base film, sending it into a tunnel oven for drying and forming, the antistatic coating is cured on the surface of the PET base film to form an antistatic coating, the thickness of the antistatic coating is controlled to be 10% of the thickness of the PET base film, and then calendering, cutting and winding are performed in sequence to obtain an antistatic plastic film; wherein, the process parameters for drying and forming are set as follows: the drying temperature of the first zone is 60°C, and the drying time is 75s; the drying temperature of the second zone is 70°C, and the drying time is 30s; the drying temperature of the third zone is 65°C, and the drying time is 25s; the drying temperature of the fourth zone is 45°C, and the drying time is 50s.

[0030] Comparative Example 1 This comparative example refers to Example 3, except that the antistatic agent is replaced by 3 parts of a commercially available CYASTAT SN type quaternary ammonium salt antistatic agent and 13 parts of graphene oxide, and the rest of the implementation process is exactly the same.

[0031] Comparative Example 2 This comparative example refers to Example 3, except that the antistatic agent is replaced by 3 parts of a commercially available CYASTAT SN type quaternary ammonium salt antistatic agent and 22 parts of graphene oxide, and the rest of the implementation process is exactly the same.

[0032] Take the above prepared membrane material, bend it 120° for 200 times, and test the surface resistivity of the membrane material before and after bending according to GB / T 1410-2006 standard. The specific test data are shown in the following table:

[0033] From the test results in the above table, it can be seen that the surface resistivity of the film material prepared in the embodiment can reach 10 7 It has excellent antistatic properties, and the surface resistivity changes little after bending. The antistatic coating maintains stable continuity under bending, making the film material have stable antistatic properties.

[0034] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0035] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. An antistatic plastic film, comprising a PET base film and an antistatic coating formed by curing an antistatic coating, characterized in that: The antistatic coating comprises, by weight: 100 parts of organic silicone resin, 12-18 parts of antistatic agent, 0.8-1.1 parts of dispersant, 0.4-0.6 parts of bridging agent, 0.15-0.2 parts of leveling agent and 55-60 parts of solvent; The antistatic agent is prepared by the following method: Step A1: Mix the silane coupling agent KH-550 and the ethanol solution, adjust the pH value to 3-4 with acetic acid, add graphene oxide and disperse by ultrasonication, stir for 1-1.5 hours, neutralize with sodium hydroxide, stand for 24 hours, wash the bottom precipitate, and dry it under nitrogen protection to obtain a modified matrix; Step A2: Mix the modified substrate, methyl chloroacetate and acetone, raise the temperature to 40-50°C, stir and intermittently add sodium hydroxide to react for 6-8h, remove the acetone under reduced pressure after the reaction, wash the substrate and vacuum dry to obtain an intermediate; Step A3: Ultrasonic dispersion of the intermediate and anhydrous tetrahydrofuran, introduction of dry nitrogen for protection, water bath temperature controlled at 35-40°C, stirring and slowly adding iodomethane for reaction for 12-15h, after the reaction is completed, tetrahydrofuran is removed by rotary evaporation to obtain an antistatic agent.

2. An antistatic plastic film according to claim 1, characterized in that: The usage ratio of graphene oxide, silane coupling agent KH-550 and ethanol solution is 10g:1.5-2.2mL:25-35mL.

3. An antistatic plastic film according to claim 2, characterized in that: The flake diameter of graphene oxide is no greater than 5 μm.

4. The antistatic plastic film according to claim 2, characterized in that: The usage ratio of the modified matrix, methyl chloroacetate, sodium hydroxide and acetone is 10g:1.2-1.8mL:0.15-0.2g:40-50mL.

5. The antistatic plastic film according to claim 4, characterized in that: The usage ratio of the intermediate, methyl iodide and anhydrous tetrahydrofuran is 10g:0.8-1.2mL:15-20mL.

6. The method for preparing an antistatic plastic film according to claim 5, characterized in that: The steps include: Step S1: premixing an antistatic agent, a dispersant, a bridging agent, a leveling agent and a solvent, and then adding an organic silicone resin and mixing well to obtain an antistatic coating; Step S2: Scrape the antistatic coating onto the surface of the PET base film, send it into a tunnel oven for drying and forming, to form an antistatic coating, and then calender, cut and roll it in sequence to obtain an antistatic plastic film.

7. The method for preparing an antistatic plastic film according to claim 6, characterized in that: The thickness of the antistatic coating is 10% of the thickness of the PET base film.

8. The method for preparing an antistatic plastic film according to claim 6, characterized in that: The process parameters of drying and molding are set as follows: the drying temperature of zone 1 is 55-65℃, and the drying time is 60-80s; the drying temperature of zone 2 is 70-80℃, and the drying time is 25-35s; the drying temperature of zone 3 is 60-70℃, and the drying time is 20-30s; the drying temperature of zone 4 is 40-50℃, and the drying time is 40-60s.

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