Antistatic film and protective film

Abstract

This invention relates to the field of polymer functional film technology, specifically to antistatic films and protective films, including a wear-resistant hardening layer, a solid antistatic functional layer, and a PET substrate layer. The antistatic film utilizes a silane-terminated PEDOT conductive polymer molecule in the solid antistatic functional layer, whose main chain is a conductive polythiophene structure with siloxane active groups chemically grafted to both ends. The siloxane groups can undergo covalent cross-linking reactions with the hydroxyl groups of the acrylic resin and the hydroxyl groups on the PET substrate surface, permanently locking the conductive molecules within the three-dimensional cross-linked network of the coating, completely blocking the channels for the conductive components to migrate and precipitate outwards. The epoxy imidazole halogen-free ionic liquid contains no free chloride, bromide, tin, antimony, or other metal ions, and together with the silane-terminated PEDOT, forms a dual-conductive synergistic system, forming a continuous conductive pathway without relying on environmental moisture. The isocyanate cross-linking agent cross-links with the acrylic resin and silane groups to construct a dense network structure, further blocking the migration of small molecule additives.

Description

Technical Field

[0001] This invention relates to the field of polymer functional film technology, and more particularly to antistatic films and protective films. Background Technology

[0002] In cleanrooms for semiconductors, optoelectronic displays, and precision electronic processing, antistatic films are typically used during product transfer to separate multiple wafers or glass substrates during stacking and to eliminate interlayer frictional static electricity.

[0003] Traditional antistatic films have many inherent defects: mainstream inexpensive antistatic films on the market use quaternary ammonium salts and alkyl sulfonates as small-molecule antistatic agents, relying on the coating to adsorb water molecules in the air to form a conductive path to dissipate static electricity. In the environment of northern winters and dust-free dry workshops (relative humidity RH < 30%), the conductive water film on the film surface disappears rapidly, and the surface resistivity instantly soars to over 10¹¹Ω, losing its electrostatic conductivity; thousands of volts of frictional static electricity are generated instantaneously during winding, slitting, and substrate separation, which can easily cause chip gate breakdown and electrostatic damage to liquid crystal pixels. Meanwhile, when the ambient temperature and humidity fluctuate slightly, the surface resistance can fluctuate by 2 to 3 orders of magnitude, resulting in extremely poor stability of antistatic performance and failing to meet the constant antistatic control standards of semiconductor workshops. Small molecule antistatic agents have small molecular weights and strong molecular mobility. During high-temperature stacking of thin films, long-term sealed storage, and hot-pressing processes, they will continuously migrate and bloom onto the film surface, forming white salt crystals and oily precipitates. These precipitates contain free chloride ions, nitrate ions, and organic acid ions. When in long-term contact with wafer aluminum electrodes, ITO conductive coatings, and optical coatings, they will form electrochemical corrosion channels, resulting in black spots, hazy stains, and rainbow corrosion patterns on the device surface. Conventional dust-free wiping and ultrasonic cleaning cannot completely remove these, directly causing the scrapping of entire batches of high-end electronic components and resulting in huge economic losses.

[0004] Therefore, there is an urgent need for an antistatic film and a protective film to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide an antistatic film and a protective film, which aims to solve the problems of antistatic failure of the antistatic film in low humidity environments and the migration and precipitation of conductive components.

[0006] To achieve the above objectives, in a first aspect, the present invention provides an antistatic film comprising a wear-resistant hardening layer, a solid antistatic functional layer, and a PET substrate layer. The wear-resistant hardening layer is fixedly connected to the solid antistatic functional layer and is located on one side of the solid antistatic functional layer. The PET substrate layer is fixedly connected to the solid antistatic functional layer and is located on the side of the solid antistatic functional layer away from the wear-resistant hardening layer. The solid antistatic functional layer comprises, by weight, 10-16 parts of silane-terminated PEDOT conductive polymer, 80 parts of aliphatic UV-curable acrylic resin, 3-6 parts of epoxy imidazole halogen-free ionic liquid, 1.2-2.5 parts of isocyanate crosslinking agent, 1.0-1.8 parts of photoinitiator 184, 0.1-0.3 parts of polyether-modified silicone leveling agent, and 140-180 parts of anhydrous ethanol.

[0007] The wear-resistant hardening layer has a thickness of 0.3–0.7 μm and is an organosilicon-modified UV-curable acrylic wear-resistant resin layer filled with nano-silica. The solid antistatic functional layer has a thickness of 0.6–1.5 μm. The PET substrate layer is a biaxially oriented PET film with a thickness of 25–100 μm. The side of the solid antistatic functional layer is pretreated with corona plasma and has a surface tension ≥52 mN / m.

[0008] In a second aspect, the present invention also provides a protective film applied to the antistatic film as described in the first aspect above, comprising an antistatic wear-resistant surface layer, a PET support substrate, an antistatic voltage-sensitive adhesive layer, and a silicone-coated release film layer. The PET support substrate is fixedly connected to the antistatic wear-resistant surface layer and is located on one side of the antistatic wear-resistant surface layer. The antistatic voltage-sensitive adhesive layer is fixedly connected to the PET support substrate and is located on the side of the PET support substrate away from the antistatic wear-resistant surface layer. The silicone-coated release film layer is fixedly connected to the antistatic voltage-sensitive adhesive layer and is located on the side of the antistatic voltage-sensitive adhesive layer away from the PET support substrate.

[0009] The antistatic and wear-resistant surface layer has a thickness of 0.4–0.8 μm and is a high-molecular permanent polyether antistatic UV-curable resin. The PET support substrate is a 30–75 μm thick biaxially oriented PET film. The antistatic voltage-sensitive adhesive layer has a thickness of 3–8 μm. The silicone-coated release film layer is a 19–50 μm thick PE release film, and the silicone transfer rate of the release coating is <0.1%.

[0010] The antistatic voltage-sensitive adhesive layer comprises, by weight, 100 parts of silicone-modified acrylic pressure-sensitive adhesive matrix, 2-3 parts of high molecular weight long-chain polyether antistatic agent, 0.8-1.5 parts of epoxy crosslinking curing agent, 0.2 parts of hindered phenolic antioxidant, and 200 parts of ethyl acetate.

[0011] The antistatic film of this invention comprises, from top to bottom, the wear-resistant hardening layer, the solid antistatic functional layer, and the PET substrate layer along the outer side of the film to the side bonded to the substrate. The side of the PET substrate layer bonded to the solid antistatic functional layer undergoes corona plasma pretreatment, resulting in a substrate surface tension ≥52 mN / m, which enhances the interlayer bonding force. In the solid antistatic functional layer, the silane-terminated PEDOT conductive polymer molecular backbone has a conductive polythiophene structure, with siloxane active groups chemically grafted at both ends of the molecule. The siloxane groups can undergo covalent cross-linking reactions with the hydroxyl groups of acrylic resin and the hydroxyl groups on the surface of the PET substrate, permanently locking the conductive molecules within the three-dimensional cross-linked network of the coating. The pathway for conductive components to migrate and precipitate outward is completely blocked. The halogen-free ionic liquid of epoxy imidazole does not contain free chloride ions, bromide ions, tin, antimony and other metal ions. Combined with silane-terminated PEDOT, it forms a dual conductive synergistic system, which can form a continuous conductive path without relying on environmental moisture. The isocyanate crosslinking agent crosslinks with acrylic resin and silane groups to construct a dense network structure, which further blocks the migration of small molecule additives. The hardened resin of the wear-resistant hardening layer is filled with nano-silica wear-resistant particles. At the same time, the resin system does not block the electrostatic conduction path and does not affect the overall antistatic performance, thus solving the problem of antistatic film failure and conductive component migration and precipitation in low humidity environment. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0013] Figure 1 This is a schematic diagram of the structure of the antistatic film provided by the present invention.

[0014] Figure 2 This is a schematic diagram of the structure of the protective film provided by the present invention.

[0015] In the diagram: 101-wear-resistant hardening layer, 102-solid antistatic functional layer, 103-PET substrate layer, 201-antistatic wear-resistant surface layer, 202-PET support substrate, 203-antistatic voltage-sensitive adhesive layer, 204-silicone coated release film layer. Detailed Implementation

[0016] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0017] Please see Figure 1In a first aspect, the present invention provides an antistatic film comprising a wear-resistant hardening layer 101, a solid antistatic functional layer 102, and a PET substrate layer 103. The wear-resistant hardening layer 101 is fixedly connected to the solid antistatic functional layer 102 and is located on one side of the solid antistatic functional layer 102. The PET substrate layer 103 is fixedly connected to the solid antistatic functional layer 102 and is located on the side of the solid antistatic functional layer 102 away from the wear-resistant hardening layer 101. The solid antistatic functional layer 102 comprises, by weight, 10-16 parts of silane-terminated PEDOT conductive polymer, 80 parts of aliphatic UV-curable acrylic resin, 3-6 parts of epoxy imidazole halogen-free ionic liquid, 1.2-2.5 parts of isocyanate crosslinking agent, 1.0-1.8 parts of photoinitiator 184, 0.1-0.3 parts of polyether-modified silicone leveling agent, and 140-180 parts of anhydrous ethanol.

[0018] In this embodiment, the side of the PET substrate layer 103 that adheres to the solid antistatic functional layer 102 undergoes corona plasma pretreatment, resulting in a substrate surface tension ≥52 mN / m, thus enhancing interlayer bonding. The solid antistatic functional layer 102 comprises, by weight, 10-16 parts of silane-terminated PEDOT conductive polymer, 80 parts of aliphatic UV-curable acrylic resin, 3-6 parts of epoxy imidazole halogen-free ionic liquid, 1.2-2.5 parts of isocyanate crosslinking agent, 1.0-1.8 parts of photoinitiator 184, 0.1-0.3 parts of polyether-modified silicone leveling agent, and 140-180 parts of anhydrous ethanol. The silane-terminated PEDOT conductive polymer in the solid antistatic functional layer 102 has a conductive polythiophene structure as its main chain, with siloxane active groups chemically grafted at both ends of the molecule. The siloxane groups can... The conductive molecules undergo a covalent cross-linking reaction with the hydroxyl groups of acrylic resin and the hydroxyl groups on the surface of PET substrate, permanently locking them inside the three-dimensional cross-linked network of the coating and completely blocking the channels for the outward migration and precipitation of conductive components. The halogen-free ionic liquid of epoxy imidazole does not contain free chloride ions, bromide ions, tin, antimony and other metal ions. Combined with silane-terminated PEDOT, it forms a dual conductive synergistic system, which can form a continuous conductive path without relying on environmental moisture. The isocyanate cross-linking agent cross-links with acrylic resin and silane groups to construct a dense network structure, further blocking the migration of small molecule additives. The hardened resin of the wear-resistant hardening layer 101 is filled with nano-silica wear-resistant particles. At the same time, the resin system does not block the electrostatic conduction path and does not affect the overall antistatic performance, thus solving the problems of antistatic film failure and conductive component migration and precipitation in low humidity environments.

[0019] Please see Figure 2Secondly, the present invention also provides a protective film applied to the antistatic film as described in the first aspect above, comprising an antistatic wear-resistant surface layer 201, a PET support substrate 202, an antistatic voltage-sensitive adhesive layer 203, and a silicone-coated release film layer 204. The PET support substrate 202 is fixedly connected to the antistatic wear-resistant surface layer 201 and is located on one side of the antistatic wear-resistant surface layer 201. The antistatic voltage-sensitive adhesive layer 203 is fixedly connected to the PET support substrate 202 and is located on the side of the PET support substrate 202 away from the antistatic wear-resistant surface layer 201. The silicone-coated release film layer 204 is fixedly connected to the antistatic voltage-sensitive adhesive layer 203 and is located on the side of the antistatic voltage-sensitive adhesive layer 203 away from the PET support substrate 202.

[0020] Furthermore, the antistatic and wear-resistant surface layer 201 has a thickness of 0.4–0.8 μm and is a high-molecular permanent polyether antistatic UV-curable resin; the PET support substrate 202 is a biaxially oriented PET film with a thickness of 30–75 μm; the antistatic voltage-sensitive adhesive layer 203 has a thickness of 3–8 μm; and the silicon-coated release film layer 204 is a PE release film with a thickness of 19–50 μm, with a silicon transfer rate of <0.1%.

[0021] Furthermore, the antistatic voltage-sensitive adhesive layer 203 comprises, by weight, 100 parts of silicone-modified acrylic pressure-sensitive adhesive matrix, 2-3 parts of high molecular weight long-chain polyether antistatic agent, 0.8-1.5 parts of epoxy crosslinking curing agent, 0.2 parts of hindered phenolic antioxidant, and 200 parts of ethyl acetate.

[0022] In this embodiment, the antistatic and wear-resistant surface layer 201 has a thickness of 0.4–0.8 μm, is coated on the outer side of the PET support substrate 202, and is made of a high-molecular permanent polyether antistatic UV-curable resin; the resin contains uniformly dispersed high-molecular segmental polyether conductive units, without the addition of small-molecule ionic antistatic agents, and the surface resistivity of the layer is stably maintained at 10. 8 ~10 9Ω, while the film surface is wear-resistant, scratch-resistant, and alcohol-resistant; the preferred thickness is 0.6μm; the PET support substrate 202 is a 30-75μm thick biaxially oriented PET film with a light transmittance ≥91.5% and a haze ≤1.1%, serving as a mechanical support carrier for the protective film; the preferred thickness is 50μm. The antistatic voltage-sensitive adhesive layer 203 is uniformly coated on the inner side of the PET support substrate 202 with a thickness of 3-8μm, and is composed of the following raw materials by weight: 100 parts of silicone-modified acrylic pressure-sensitive adhesive matrix, 2-3 parts of high molecular weight long-chain polyether antistatic agent, 0.8-1.5 parts of epoxy crosslinking curing agent, 0.2 parts of hindered phenolic antioxidant, and 200 parts of ethyl acetate diluent; the adhesive layer tack is controlled at 5-15g / 25mm (180° peel force), belonging to a light tack system, and can be peeled after baking at room temperature and 120℃ for 72 hours. The device surface is free of residual adhesive, adhesive marks, and white haze pollution; the high-molecular-weight polyether antistatic agent is cross-linked and fused with the acrylic adhesive matrix, eliminating the risk of small molecule precipitation; the epoxy curing agent increases the cross-linking density of the adhesive layer and inhibits the migration of low-molecular-weight plasticizers within the adhesive layer; the antioxidant improves the thermal stability of the adhesive layer, preventing yellowing during long-term high-temperature stacking; the preferred coating thickness of this adhesive layer is 5μm, with the optimal ratio: 100 parts of silicone-modified acrylic pressure-sensitive adhesive, 2.5 parts of high-molecular-weight long-chain polyether antistatic agent, 1.2 parts of epoxy cross-linking curing agent, and 0.2 parts of hindered phenolic antioxidant; the silicone-coated release film layer 204 is a 19-50μm thick polyethylene (PE) release film adhered to the surface of the antistatic voltage-sensitive adhesive layer 203, with a single-sided coating of an ultra-thin silicone release coating, a silicon transfer rate of <0.1%, and no silicon elements are transferred to the adhesive layer and device surface when the release film is removed; the preferred thickness is 25μm.

[0023] To better understand this technical solution, the following embodiments and comparative examples are provided for further explanation:

[0024] Example

[0025] Antistatic film structure: 50μm PET substrate layer 103, 1.0μm covalently anchored antistatic functional layer 102, 0.5μm wear-resistant hardening layer 101; the antistatic functional layer adopts the optimal ratio: 13 parts silane-terminated PEDOT, 80 parts aliphatic UV-curable acrylic resin, 4.5 parts epoxy imidazole halogen-free ionic liquid, 1.8 parts isocyanate crosslinking agent, 1.4 parts photoinitiator 184, 0.2 parts polyether modified silicone leveling agent, and 160 parts anhydrous ethanol;

[0026] The wear-resistant hardened layer 101 is an organosilicon-modified acrylic wear-resistant resin filled with nano-silica;

[0027] Performance testing: Surface resistivity at RH20% ambient temperature: 6.5 × 10⁻⁶ 7 Ω, RH 75% environment 6.2×10 7Ω; Overall transmittance 91.9%, haze 1.1%; Total ion deposition 0.006 μg / cm³ 2 Baking at 120℃ for 72 hours only increased the resistance by 3.6%; the coating remained intact and did not peel off after 100 alcohol wipes.

[0028] Protective film structure: 0.6μm antistatic and wear-resistant surface layer 201, 50μm PET support substrate 202, 5μm antistatic voltage-sensitive adhesive layer 203, 25μm silicone-coated PE release film; Optimal formulation of pressure-sensitive adhesive: 100 parts silicone-modified acrylic pressure-sensitive adhesive, 2.5 parts high-molecular-weight long-chain polyether antistatic agent, 1.2 parts epoxy crosslinking curing agent, 0.2 parts hindered phenolic antioxidant, 200 parts ethyl acetate; Performance testing: Surface resistivity of film 7.1×10⁻⁶. 8 Ω; 180° peel strength 10g / 25mm; no residue or adhesive mark after baking at 120℃ for 72h; overall light transmittance 91.6%, haze 1.08%; silicon transfer rate 0.06%.

[0029] Complete set of tests: After stacking and sealing the antistatic isolation film and protective film for 72 hours, there is no charge accumulation at the film interface and no ion cross-deposition. It can be used simultaneously for wafer interlayer isolation and display panel surface bonding protection, and is suitable for use in the entire process of cleanroom.

[0030] Comparative Example

[0031] Traditional small-molecule antistatic membranes have a surface resistance >10 ohms under low humidity (RH 20%). 11 Ω, after baking at 120℃ for 48 hours, white oil spots appeared on the film surface; ordinary protective film has no antistatic modification, and the electrostatic voltage is >8000V at the moment of peeling the film, and adhesive residue remains on the product surface after peeling; after the double film is stacked for 72 hours, the additives migrate and precipitate out, and dotted corrosion black spots appear on the surface of optical glass, making it unsuitable for the protection of high-end precision products.

[0032] The above-disclosed embodiments are merely preferred embodiments of the antistatic film and protective film of this application and should not be construed as limiting the scope of the claims of this application. Those skilled in the art can understand that all or part of the processes for implementing the above embodiments and equivalent changes made in accordance with the claims of this application still fall within the scope of this application.

Claims

1. An antistatic film, characterized in that, It includes a wear-resistant hardening layer, a solid antistatic functional layer and a PET substrate layer. The wear-resistant hardening layer is fixedly connected to the solid antistatic functional layer and is located on one side of the solid antistatic functional layer. The PET substrate layer is fixedly connected to the solid antistatic functional layer and is located on the side of the solid antistatic functional layer away from the wear-resistant hardening layer. The solid antistatic functional layer comprises, by weight, 10-16 parts of silane-terminated PEDOT conductive polymer, 80 parts of aliphatic UV-curable acrylic resin, 3-6 parts of epoxy imidazole halogen-free ionic liquid, 1.2-2.5 parts of isocyanate crosslinking agent, 1.0-1.8 parts of photoinitiator 184, 0.1-0.3 parts of polyether-modified silicone leveling agent, and 140-180 parts of anhydrous ethanol.

2. The antistatic film as described in claim 1, characterized in that, The wear-resistant hardening layer has a thickness of 0.3–0.7 μm and is an organosilicon-modified UV-curable acrylic wear-resistant resin layer filled with nano-silica. The solid antistatic functional layer has a thickness of 0.6–1.5 μm. The PET substrate layer is a biaxially oriented PET film with a thickness of 25–100 μm. The side of the solid antistatic functional layer is pretreated with corona plasma and has a surface tension ≥52 mN / m.

3. A protective film, applied to the antistatic film as described in any one of claims 1-2, characterized in that, The device includes an antistatic and wear-resistant surface layer, a PET support substrate, an antistatic voltage-sensitive adhesive layer, and a silicone-coated release film layer. The PET support substrate is fixedly connected to the antistatic and wear-resistant surface layer and is located on one side of the antistatic and wear-resistant surface layer. The antistatic voltage-sensitive adhesive layer is fixedly connected to the PET support substrate and is located on the side of the PET support substrate away from the antistatic and wear-resistant surface layer. The silicone-coated release film layer is fixedly connected to the antistatic voltage-sensitive adhesive layer and is located on the side of the antistatic voltage-sensitive adhesive layer away from the PET support substrate.

4. The protective film as described in claim 3, characterized in that, The antistatic and wear-resistant surface layer has a thickness of 0.4–0.8 μm and is a high-molecular permanent polyether antistatic UV-curable resin. The PET support substrate is a 30–75 μm thick biaxially oriented PET film. The antistatic voltage-sensitive adhesive layer has a thickness of 3–8 μm. The silicone-coated release film layer is a 19–50 μm thick PE release film, and the silicone transfer rate of the release coating is <0.1%.

5. The protective film as described in claim 3, characterized in that, The antistatic voltage-sensitive adhesive layer comprises, by weight, 100 parts of silicone-modified acrylic pressure-sensitive adhesive matrix, 2-3 parts of high molecular weight long-chain polyether antistatic agent, 0.8-1.5 parts of epoxy crosslinking curing agent, 0.2 parts of hindered phenolic antioxidant, and 200 parts of ethyl acetate.

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