Antistatic pet aluminized film and pet film composite flat sheet printing material and preparation method thereof

Abstract

This invention relates to an antistatic PET aluminized film and PET film composite sheet printing material and its preparation method. The composite sheet printing material comprises a first antistatic coating, a PET aluminized film layer, a conductive adhesive layer, a PET film layer, and a second antistatic coating, sequentially stacked from the printing side to the back side. The PET aluminized film layer includes a PET base film layer and an aluminum layer, with the aluminum layer coated on the side of the PET base film layer closest to the conductive adhesive layer. This invention constructs a triple synergistic antistatic mechanism of "aluminum layer conductivity + conductive adhesive layer conductivity + double-sided antistatic coating," effectively eliminating static electricity problems in the sheet printing process and fundamentally solving static electricity problems such as adhesion and ink splatter in the sheet printing process.

Description

Technical Field

[0001] This invention relates to the field of printing and packaging materials technology, specifically to an antistatic PET aluminized film and PET film composite sheet printing material and its preparation method. Background Technology

[0002] PET (polyethylene terephthalate) film is widely used in the printing and packaging industry due to its excellent mechanical properties, heat resistance, chemical resistance, and dimensional stability. Metallized PET film, by coating an aluminum layer onto the surface of a PET substrate, not only gives the material a good metallic luster and barrier properties, but the aluminum layer also has a certain degree of conductivity, which can dissipate static electricity to some extent.

[0003] In recent years, printing materials formed by laminating PET metallized film and PET film have become increasingly widely used in high-end packaging, labels, and cards due to their advantages such as metallic luster, good stiffness, and dimensional stability. In sheet-fed printing, PET metallized film, as a roll material, requires subsequent processing such as slitting and lamination. However, PET itself is an insulating polymer material, and static electricity is easily generated and accumulated during production and processing due to friction. When PET metallized film and PET film are laminated, the triboelectric charging phenomenon between the two insulating layers is particularly severe. The resulting static electricity can lead to problems such as sheet adhesion (adjacent sheets of printing material sticking together due to electrostatic adsorption) and ink splatter during sheet-fed printing, seriously affecting printing quality and production efficiency.

[0004] In existing technologies, antistatic treatment typically involves coating the surface of printing materials with an antistatic coating. For example, Chinese Patent Publication No. CN103640353B discloses an antistatic layer for medical films. The medical film includes a substrate and a coating on the substrate. The substrate includes a transparent or semi-transparent PET sheet, and the coating includes an antistatic layer and an intermediate adhesive layer. The antistatic effect is achieved by adding a polyaniline antistatic agent to the raw materials of the antistatic layer. As another example, Chinese Patent Publication No. CN118792914A discloses an antistatic gold and silver card digital paper. Its structure includes a digital paper base layer, an adhesive layer, an aluminized film, a thin film layer, and an antistatic layer. The static electricity problem during the gold and silver card printing process is solved by setting an antistatic layer containing conductive fillers and an antistatic agent on the outermost layer.

[0005] However, the aforementioned existing antistatic methods are all limited to applying a single-layer antistatic coating to the outermost layer of the material. The adhesive layer is an insulating adhesive and lacks interlayer electrostatic conductivity. For sheet-fed printing materials composed of PET metallized film and PET film, interlayer static electricity cannot be dissipated through the insulating adhesive layer, leading to continuous accumulation of static electricity. Therefore, the surface antistatic coating alone cannot fundamentally solve the problems of adhesion and ink splatter.

[0006] Therefore, there is considerable room for improvement in the existing technology. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing an antistatic PET aluminized film and PET film composite sheet printing material and its preparation method. This composite sheet printing material effectively eliminates static electricity problems during sheet printing by using a conductive adhesive layer to conduct static electricity between layers, combined with the synergistic effect of the aluminum layer and two antistatic coatings.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A sheet-fed printing material composed of an antistatic PET aluminized film and a PET film, comprising a first antistatic coating, a PET aluminized film layer, a conductive adhesive layer, a PET film layer, and a second antistatic coating layer, which are sequentially stacked from the printing side to the back side; the PET aluminized film layer comprises a PET base film layer and an aluminum layer, wherein the aluminum layer is coated on the side of the PET base film layer near the conductive adhesive layer.

[0009] The first antistatic coating is applied to the printing surface of the composite sheet-fed printing material, serving both antistatic and printing base functions. The PET base film layer provides the composite sheet-fed printing material with good mechanical properties, dimensional stability, and heat resistance; the aluminum layer itself has metallic conductivity, which can dissipate static electricity in the layer it is located in. The conductive adhesive layer has both adhesive and conductive functions. The PET film layer provides support and stiffness to the composite sheet-fed printing material. The second antistatic coating is applied to the back side of the composite sheet-fed printing material to reduce the surface resistance of the back side.

[0010] By positioning the aluminum layer between the PET base film layer and the conductive adhesive layer, the aluminum layer can directly contact the conductive adhesive layer. This allows the static electricity collected in the aluminum layer to be conducted through the conductive adhesive layer to the second antistatic coating of the PET film layer, achieving effective dissipation of static electricity between layers. The conductive adhesive layer, combined with the aluminum layer and the two antistatic coatings, forms a multi-layer conductive pathway structure of "first antistatic coating—conductive aluminum layer—conductive adhesive layer—second antistatic coating," thereby achieving synergistic dissipation of static electricity between layers and effectively eliminating static electricity problems during sheet-fed printing.

[0011] Preferably, both the first antistatic coating and the second antistatic coating are configured as water-based antistatic varnish coatings, wherein the water-based antistatic varnish coating comprises, by weight, the following raw materials: 40-60 parts of water-based film-forming resin, 10-30 parts of conductive polymer, 1-5 parts of adhesion promoter, 0.5-2 parts of wetting agent, 1-5 parts of dispersant, 2-6 parts of leveling agent, and 10-40 parts of deionized water.

[0012] Waterborne film-forming resin serves as the main coating component, forming a continuous clear varnish film and providing a foundation for adhesion. It has low VOC content and is environmentally friendly. Conductive polymers provide antistatic properties and reduce surface resistance. Adhesion promoters enhance the bonding force between the coating and the PET base film and ink. The addition of wetting agents reduces the surface tension of the coating liquid and improves its spreadability on the PET surface. Dispersants promote the uniform dispersion of conductive polymers and other components. Leveling agents improve the appearance quality of the coating and eliminate defects such as orange peel and pinholes.

[0013] Preferably, the aqueous film-forming resin is one or more of aqueous polyurethane resin, aqueous acrylic resin, and aqueous acrylic-polyurethane hybrid resin; the conductive polymer is one or two of polyaniline and PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate); and the adhesion promoter is one or more of silane coupling agent, titanate coupling agent, and polyester adhesion promoter.

[0014] Preferably, the conductive adhesive layer comprises, by weight, the following raw materials: 50-70 parts of waterborne polyurethane adhesive, 5-20 parts of conductive filler, 1-5 parts of coupling agent, 2-8 parts of crosslinking agent, and 10-30 parts of deionized water.

[0015] Waterborne polyurethane adhesive provides the bonding matrix, ensuring adhesion strength; conductive fillers form a conductive network, dissipating interlayer static electricity; coupling agents react chemically with the adhesive molecular chains through their organic functional groups, while inorganic functional groups form chemical bonds with the surface of the aluminized layer, thus creating a strong chemical bond between the adhesive and the aluminized layer. The crosslinking agent enables the adhesive layer to form a three-dimensional network structure, improving the cohesive strength of the adhesive layer. After the adhesive cures, the conductive fillers in the conductive adhesive layer form a continuous conductive network throughout the adhesive layer, establishing an electrostatic conduction path between the aluminum layer of the PET aluminized film and the PET film layer, allowing interlayer static electricity to dissipate through the conductive adhesive layer. Simultaneously, the waterborne polyurethane adhesive ensures good adhesion strength of the composite sheet-fed printing material, and the synergistic use of coupling agents and crosslinking agents further improves the cohesive strength and interfacial bonding of the adhesive layer.

[0016] Preferably, the conductive filler is one or more of carbon nanotubes, conductive carbon black, and graphene; the coupling agent is a silane coupling agent; and the crosslinking agent is an aziridine crosslinking agent or an isocyanate crosslinking agent.

[0017] Preferably, the total thickness of the PET aluminized film layer is 12-50 μm, wherein the thickness of the aluminum layer is 0.03-0.06 μm; the thickness of the PET film layer is 100-300 μm; the thickness of the first antistatic coating and the second antistatic coating are each independently 1-3 μm; and the thickness of the conductive adhesive layer is 2-8 μm.

[0018] The total thickness of the PET aluminized film layer is 12–50 μm, ensuring both the stiffness and dimensional stability of the composite sheet printing material while avoiding curling problems caused by excessive film thickness. The aluminum layer thickness is controlled at 0.03–0.06 μm, ensuring good conductivity and metallic luster while controlling adhesion to the PET substrate and production costs. The PET film layer thickness is 100–300 μm, ensuring the stiffness and printability of the composite sheet printing material. Both the first and second antistatic coatings are controlled at 1–3 μm, ensuring both antistatic effect and ink adhesion while avoiding cracking or reduced transparency caused by excessive coating thickness. The conductive adhesive layer thickness is 2–8 μm, ensuring the thickness required for the conductive filler to form a continuous conductive network while also ensuring bonding strength, and avoiding insufficient drying or increased costs caused by excessive adhesive layer thickness.

[0019] This invention also provides a method for preparing the above-mentioned antistatic PET metallized film and PET film composite sheet printing material, comprising the following steps: (1) The PET base film layer is subjected to corona treatment, and an aluminum layer is deposited on one side of the PET base film layer by vacuum evaporation under vacuum conditions to obtain an aluminum-coated PET film layer. (2) Mix the raw materials of the water-based antistatic varnish coating evenly to obtain the water-based antistatic varnish coating liquid; coat the water-based antistatic varnish coating liquid on the other side surface of the PET base film layer and the other side surface of the PET film layer respectively, and dry and cure to form the first antistatic coating and the second antistatic coating. (3) Mix the raw materials of the conductive adhesive layer evenly to obtain a conductive adhesive; apply the conductive adhesive to the surface of the aluminum layer or the other side of the PET film layer, and after pre-drying, bond the PET aluminized film to the PET film, and cure the conductive adhesive by curing. (4) After static electricity elimination treatment, cut into flat sheets according to specifications.

[0020] Corona treatment can improve the surface energy of the PET base film layer and ensure the adhesion of the aluminum layer; vacuum evaporation can form a dense and uniform aluminum layer, ensuring conductivity and gloss.

[0021] Preferably, in step (1), the PET base film layer is subjected to corona treatment, and the surface tension reaches 42-48 dyn / cm; the aluminum layer is deposited by vacuum evaporation, and the vacuum degree is not less than 1.0×10⁻²Pa.

[0022] Preferably, in step (2), the water-based antistatic varnish is coated using a rod coating method, a gravure coating method, or a micro-gravure coating method, with a coating amount of 3-8 g / m² on a wet basis. After coating, a segmented drying process is adopted: preheating at 60°C for 1-3 min, main drying at 80°C for 1-3 min, and curing at 100°C for 1-3 min.

[0023] Segmented drying ensures uniform film formation and avoids defects such as pinholes and sagging, while also guaranteeing the curing degree and adhesion of the coating.

[0024] Preferably, in step (3), a dry composite process is used for bonding, the coating amount of the conductive adhesive layer is 3-10 g / m² on a dry basis, the pre-drying temperature is 60-100℃, the bonding pressure is 3-6 kg / cm², the bonding speed is 10-30 m / min, the curing temperature is 40-60℃, and the curing time is 24-72 hours.

[0025] Dry lamination is a mature and reliable process that can guarantee bonding strength and lamination quality; appropriate curing conditions can ensure that the adhesive is fully cross-linked, improving bonding strength and weather resistance.

[0026] Preferably, in step (4), an ionizer or static eliminator is used for static elimination treatment; the dimensions of the cut sheets include, but are not limited to, 520mm×740mm and 787mm×1092mm. Static elimination treatment before cutting can prevent static electricity generated during the cutting process from affecting subsequent finishing and packaging.

[0027] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention constructs a triple synergistic antistatic mechanism consisting of "conductive aluminum layer + conductive adhesive layer + double-sided antistatic coating." The conductive adhesive layer acts as an "electrostatic bridge," conducting the interlayer static electricity between the aluminized PET film and the PET sheet, thus solving the core problem of the insulating adhesive layer blocking static electricity conduction in existing technologies. The synergistic effect of these three components effectively eliminates static electricity problems during sheet printing, fundamentally solving issues such as adhesion and ink splatter during sheet printing. 2. The adhesion promoter in the water-based antistatic varnish coating material forms chemical bonds or hydrogen bonds with the polar regions of the PET surface through the polar groups in its molecular structure, which act as a "chemical bridge" between the coating and the ink, so that the ink adhesion reaches level 0, effectively solving the problem of ink smudging during printing. 3. The coupling agent in the conductive adhesive layer enhances the interfacial bonding force between the adhesive and the aluminum-plated layer and the PET film surface, while the crosslinking agent enables the adhesive layer to form a three-dimensional network structure, improving the cohesive strength of the adhesive layer. The peel strength of the composite sheet printing material can reach more than 5.5 N / cm. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the present invention.

[0029] In the figure: 1. First antistatic coating; 2. PET aluminized film layer; 21. PET base film layer; 22. Aluminum layer; 3. Conductive adhesive layer; 4. PET film layer; 5. Second antistatic coating. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0031] Example 1

[0032] like Figure 1 As shown, this invention provides a sheet-fed printing material composite of antistatic PET aluminized film and PET film, comprising a first antistatic coating 1, a PET aluminized film layer 2, a conductive adhesive layer 3, a PET film layer 4, and a second antistatic coating 5, sequentially stacked from the printing surface to the back surface; the PET aluminized film layer 2 includes a PET base film layer 21 and an aluminum layer 22, the aluminum layer 22 being coated on the side of the PET base film layer 21 near the conductive adhesive layer 3; both the first antistatic coating 1 and the second antistatic coating 5 are water-based antistatic varnish coatings; the total thickness of the PET aluminized film layer 2 is 12 μm, wherein the thickness of the aluminum layer 22 is 0.03 μm; the thickness of the PET film layer 4 is 100 μm; the thickness of the first antistatic coating 1 is 1 μm, the thickness of the second antistatic coating 5 is 2 μm; and the thickness of the conductive adhesive layer 3 is 2 μm.

[0033] Furthermore, the water-based antistatic varnish coating comprises, by weight, the following raw materials: 40 parts water-based film-forming resin, 10 parts conductive polymer, 1 part adhesion promoter, 0.5 parts wetting agent, 1 part dispersant, 2 parts leveling agent, and 10 parts deionized water; wherein the water-based film-forming resin is water-based polyurethane resin; the conductive polymer is polyaniline; and the adhesion promoter is silane coupling agent KH-550.

[0034] Further, the conductive adhesive layer 3 comprises, by weight, the following raw materials: 50 parts of water-based polyurethane adhesive, 5 parts of conductive filler, 1 part of coupling agent, 2 parts of crosslinking agent, and 10 parts of deionized water; wherein the conductive filler is carbon nanotubes; the coupling agent is silane coupling agent KH-560; and the crosslinking agent is aziridine crosslinking agent.

[0035] The preparation method of the antistatic PET aluminized film and PET film composite sheet printing material includes the following steps: (1) The PET base film layer 21 is subjected to corona treatment to make the surface tension reach 42dyn / cm. Under the vacuum degree of 1.0×10⁻²Pa, an aluminum layer 22 is deposited on one side of the PET base film layer 21 by vacuum evaporation to obtain the PET aluminum film layer 2. (2) Mix the raw materials of the water-based antistatic varnish coating evenly to obtain the water-based antistatic varnish coating liquid; apply the water-based antistatic varnish coating liquid to the other side surface of the PET base film layer 21 and the side surface of the PET film layer 4 by the rod coating method, and dry and cure to form the first antistatic coating 1 and the second antistatic coating 5; wherein, the coating amount of the water-based antistatic varnish coating liquid is 3g / m² on wet basis; after coating, adopt a segmented drying process: preheat at 60℃ for 1min, main drying at 80℃ for 1min, and curing at 100℃ for 1min; (3) Mix the raw materials of conductive adhesive layer 3 evenly to obtain conductive adhesive; apply the conductive adhesive to the surface of aluminum layer 22 or the other side of PET film layer 4, and after pre-drying, use a dry composite process to bond the PET aluminum film layer 2 and the PET film layer 4 together, and cure the conductive adhesive to fully crosslink and solidify; wherein, the coating amount of the conductive adhesive is 3g / m² on a dry basis, the pre-drying temperature is 60℃, the bonding pressure is 3kg / cm², the bonding speed is 10m / min, the curing temperature is 40℃, and the curing time is 72 hours; (4) After static elimination treatment by ion air bar, cut into flat sheets according to the specifications of 520mm×740mm.

[0036] Example 2 This invention provides a sheet-fed printing material composite of antistatic PET aluminized film and PET film, comprising a first antistatic coating 1, a PET aluminized film layer 2, a conductive adhesive layer 3, a PET film layer 4, and a second antistatic coating 5, sequentially stacked from the printing side to the back side; the PET aluminized film layer 2 includes a PET base film layer 21 and an aluminum layer 22, the aluminum layer 22 being coated on the side of the PET base film layer 21 near the conductive adhesive layer 3; both the first antistatic coating 1 and the second antistatic coating 5 are water-based antistatic varnish coatings; the total thickness of the PET aluminized film layer 2 is 38 μm, wherein the thickness of the aluminum layer 22 is 0.04 μm; the thickness of the PET film layer 4 is 150 μm; the thickness of the first antistatic coating 1 is 1.5 μm; the thickness of the second antistatic coating 5 is 1 μm; and the thickness of the conductive adhesive layer 3 is 5 μm.

[0037] Further, the water-based antistatic varnish coating comprises, by weight, the following raw materials: 50 parts water-based film-forming resin, 20 parts conductive polymer, 3 parts adhesion promoter, 1.5 parts wetting agent, 3 parts dispersant, 4 parts leveling agent, and 25 parts deionized water; wherein the water-based film-forming resin is a mixture of 25 parts water-based acrylic resin and 25 parts water-based acrylic-polyurethane hybrid resin; the conductive polymer is PEDOT:PSS; and the adhesion promoter is a titanate coupling agent.

[0038] Further, the conductive adhesive layer 3, by weight, comprises the following raw materials: 60 parts of waterborne polyurethane adhesive, 13 parts of conductive filler, 3 parts of coupling agent, 4 parts of crosslinking agent, and 20 parts of deionized water; wherein the conductive filler is a mixture of 10 parts of conductive carbon black and 3 parts of graphene; the coupling agent is silane coupling agent KH-560; and the crosslinking agent is an isocyanate crosslinking agent.

[0039] The preparation method of the antistatic PET aluminized film and PET film composite sheet printing material includes the following steps: (1) The PET base film layer 21 is subjected to corona treatment to make the surface tension reach 45dyn / cm. Under the vacuum degree of 1.5×10⁻²Pa, an aluminum layer 22 is deposited on one side of the PET base film layer 21 by vacuum evaporation to obtain the PET aluminum film layer 2. (2) Mix the raw materials of the water-based antistatic varnish coating evenly to obtain the water-based antistatic varnish coating liquid; apply the water-based antistatic varnish coating liquid to the other side surface of the PET base film layer 21 and the side surface of the PET film layer 4 respectively by gravure coating method, and dry and cure to form the first antistatic coating 1 and the second antistatic coating 5; wherein, the coating amount of the water-based antistatic varnish coating liquid is 5g / m² on wet basis; after coating, adopt a segmented drying process: preheating at 60℃ for 2min, main drying at 80℃ for 2min, and curing at 100℃ for 2min; (3) Mix the raw materials of conductive adhesive layer 3 evenly to obtain conductive adhesive; apply the conductive adhesive to the surface of aluminum layer 22 or the other side of PET film layer 4, and after pre-drying, bond the PET aluminized film layer 2 and the PET film layer 4 using a dry composite process, and cure the conductive adhesive to fully crosslink and solidify; wherein, the coating amount of the conductive adhesive is 7 g / m² on a dry basis, the pre-drying temperature is 80℃, the bonding pressure is 5 kg / cm², the bonding speed is 20 m / min, the curing temperature is 50℃, and the curing time is 48 hours; (4) After static elimination treatment by ion air bar, cut into flat sheets according to the specifications of 520mm×740mm.

[0040] Example 3 This invention provides a sheet-fed printing material composite of antistatic PET aluminized film and PET film, comprising a first antistatic coating 1, a PET aluminized film layer 2, a conductive adhesive layer 3, a PET film layer 4, and a second antistatic coating 5, sequentially stacked from the printing side to the back side; the PET aluminized film layer 2 includes a PET base film layer 21 and an aluminum layer 22, the aluminum layer 22 being coated on the side of the PET base film layer 21 near the conductive adhesive layer 3; both the first antistatic coating 1 and the second antistatic coating 5 are water-based antistatic varnish coatings; the total thickness of the PET aluminized film layer 2 is 50 μm, wherein the thickness of the aluminum layer 22 is 0.06 μm; the thickness of the PET film layer 4 is 300 μm; the thickness of the first antistatic coating 1 is 3 μm, the thickness of the second antistatic coating 5 is 3 μm; and the thickness of the conductive adhesive layer 3 is 8 μm.

[0041] Further, the water-based antistatic varnish coating comprises, by weight, the following raw materials: 60 parts water-based film-forming resin, 30 parts conductive polymer, 5 parts adhesion promoter, 2 parts wetting agent, 5 parts dispersant, 6 parts leveling agent, and 40 parts deionized water; wherein the water-based film-forming resin is a water-based acrylic resin; the conductive polymer is PEDOT:PSS; and the adhesion promoter is a mixture of 3 parts titanate coupling agent and 2 parts polyester-type adhesion promoter.

[0042] Further, the conductive adhesive layer 3, by weight, comprises the following raw materials: 70 parts of water-based polyurethane adhesive, 20 parts of conductive filler, 5 parts of coupling agent, 8 parts of crosslinking agent, and 30 parts of deionized water; wherein the conductive filler is conductive carbon black; the coupling agent is silane coupling agent KH-560; and the crosslinking agent is aziridine crosslinking agent.

[0043] The preparation method of the antistatic PET aluminized film and PET film composite sheet printing material includes the following steps: (1) The PET base film layer 21 is subjected to corona treatment to make the surface tension reach 48dyn / cm. Under the vacuum degree of 1.0×10⁻²Pa, an aluminum layer 22 is deposited on one side of the PET base film layer 21 by vacuum evaporation to obtain the PET aluminum film layer 2. (2) Mix the raw materials of the water-based antistatic varnish coating evenly to obtain the water-based antistatic varnish coating liquid; use a micro-gravure coating method to coat the water-based antistatic varnish coating liquid onto the other side surface of the PET base film layer 21 and the side surface of the PET film layer 4 respectively, and dry and cure to form the first antistatic coating 1 and the second antistatic coating 5; wherein, the coating amount of the water-based antistatic varnish coating liquid is 3g / m² on a wet basis; after coating, a segmented drying process is adopted: preheating at 60℃ for 3min, main drying at 80℃ for 3min, and curing at 100℃ for 3min; (3) Mix the raw materials of conductive adhesive layer 3 evenly to obtain conductive adhesive; apply the conductive adhesive to the surface of aluminum layer 22 or the other side of PET film layer 4, and after pre-drying, bond the PET aluminum-plated film layer 2 and the PET film layer 4 using a dry composite process, and cure the conductive adhesive to fully crosslink and solidify; wherein, the coating amount of the conductive adhesive is 10g / m² on a dry basis, the pre-drying temperature is 100℃, the bonding pressure is 6kg / cm², the bonding speed is 30m / min, the curing temperature is 60℃, and the curing time is 24 hours; (4) After static elimination treatment by ion air bar, cut into flat sheets according to the specifications of 520mm×740mm.

[0044] Comparative Example 1 This comparative example provides a sheet printing material composite of PET aluminized film and PET film, the structure of which is basically the same as that of Example 1, except that: no first antistatic coating and second antistatic coating are provided.

[0045] The remaining structure and preparation method are the same as in Example 1.

[0046] Comparative Example 2 This comparative example provides a flat sheet printing material composed of PET aluminized film and PET film, the structure of which is basically the same as that of Example 1, except that a second antistatic coating 5 is not provided.

[0047] The remaining structure and preparation method are the same as in Example 1.

[0048] Comparative Example 3 This comparative example provides a sheet printing material composite of PET aluminized film and PET film, the structure of which is basically the same as that of Example 1, except that the conductive adhesive layer does not contain conductive fillers, that is, ordinary water-based polyurethane adhesive is used.

[0049] The remaining structure and preparation method are the same as in Example 1.

[0050] Comparative Example 4 This comparative example provides a composite sheet printing material of PET aluminized film and PET film, which has a structure that is basically the same as that of Example 1, except that the raw materials of the water-based antistatic varnish coating do not include an adhesion promoter.

[0051] The remaining structure and preparation method are the same as in Example 1.

[0052] The composite sheet printing materials obtained in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests, and the test methods are as follows: (1) Surface resistance test: The surface resistance of the sample was tested using an electrostatic tester in accordance with ASTM D257 standard; (2) Peel strength test: A 90° peel test was conducted according to GB / T 8808 standard to test the peel strength between the PET aluminized film layer and the PET film layer; (3) Printing ink adhesion test: Solid color blocks are printed on the printing surface of the sample using offset printing. After drying, the ink adhesion is evaluated according to GB / T 9286 standard (3M tape peeling method) to evaluate the ink adhesion level (0 is the best and 5 is the worst). (4) Triboelectric voltage test: The electrostatic voltage of the sample after standard friction was tested using a triboelectric electrostatic tester in accordance with JIS L 1094 standard; (5) Adhesion test: Stack 100 samples and place them in an environment with a temperature of 25℃ and a relative humidity of 50% for 24 hours, and observe whether there is adhesion.

[0053] The test results are shown in the table below:

[0054] As can be seen from the test results in the table above: (1) The surface resistance of the composite sheet printing material obtained by this invention is stable at 10. 7 ~10 8 (1) The surface resistance of Comparative Example 1 (without antistatic coating) is as high as 10¹²Ω or more, the triboelectric voltage exceeds 500V, and the adhesion phenomenon is serious, which verifies the necessity of the surface antistatic coating. (2) Comparative Example 2 has only the first antistatic coating on the printed surface and no second antistatic coating on the back (the back is bare PET); its printed surface resistance is basically the same as that of Example 1, but the back surface resistance is >10¹¹Ω, the overall triboelectric voltage exceeds 400V, and the adhesion phenomenon still appears when the sheets are stacked flat, which verifies the necessity of the double-sided antistatic coating for synergistic antistatic. (3) Comparative Example 2 (conductive adhesive layer without conductive filler) has a surface resistance of more than 10¹¹Ω, a triboelectric voltage of more than 300V, and the adhesion phenomenon is obvious, which shows that the "static bridge" function of the conductive adhesive layer is crucial - only by conducting the static electricity between the layers can the overall antistatic effect be achieved. (5) Although Comparative Example 4 (antistatic coating without adhesion promoter) has good surface resistance and antistatic properties, the ink adhesion is significantly reduced (≥2 level), and ink smudging is obvious, indicating that the adhesion promoter plays an important role in ensuring printability. (6) The peel strength between the PET aluminized film layer and the PET film layer of the present invention reaches more than 5.5 N / cm, indicating that the conductive adhesive layer can still ensure good bonding strength while achieving the conductive function.

[0055] The above description is only a preferred embodiment of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of this patent application are included in the scope of this patent application.

Claims

1. A sheet printing material composite of antistatic PET aluminized film and PET film, characterized in that, It includes a first antistatic coating (1), a PET aluminized film layer (2), a conductive adhesive layer (3), a PET film layer (4), and a second antistatic coating (5) that are stacked sequentially from the printed side to the back side. The PET aluminized film layer (2) includes a PET base film layer (21) and an aluminum layer (22), wherein the aluminum layer (22) is coated on the side of the PET base film layer (21) near the conductive adhesive layer (3).

2. The antistatic PET aluminized film and PET film composite sheet printing material according to claim 1, characterized in that, Both the first antistatic coating (1) and the second antistatic coating (5) are water-based antistatic varnish coatings; The water-based antistatic varnish coating comprises, by weight, the following raw materials: 40-60 parts water-based film-forming resin, 10-30 parts conductive polymer, 1-5 parts adhesion promoter, 0.5-2 parts wetting agent, 1-5 parts dispersant, 2-6 parts leveling agent, and 10-40 parts deionized water.

3. The antistatic PET aluminized film and PET film composite sheet printing material according to claim 2, characterized in that, The aqueous film-forming resin is one or more of the following: aqueous polyurethane resin, aqueous acrylic resin, and aqueous acrylic-polyurethane hybrid resin. The conductive polymer is one or both of polyaniline and PEDOT:PSS; The adhesion promoter is one or more of silane coupling agents, titanate coupling agents, and polyester-type adhesion promoters.

4. The antistatic PET aluminized film and PET film composite sheet printing material according to claim 1, characterized in that, The conductive adhesive layer (3) comprises the following raw materials by mass: 50-70 parts of waterborne polyurethane adhesive, 5-20 parts of conductive filler, 1-5 parts of coupling agent, 2-8 parts of crosslinking agent, and 10-30 parts of deionized water.

5. The antistatic PET aluminized film and PET film composite sheet printing material according to claim 4, characterized in that, The conductive filler is one or more of carbon nanotubes, conductive carbon black, and graphene. The coupling agent is a silane coupling agent; The crosslinking agent is a aziridine crosslinking agent or an isocyanate crosslinking agent.

6. The antistatic PET aluminized film and PET film composite sheet printing material according to claim 1, characterized in that, The total thickness of the PET aluminized film layer (2) is 12-50 μm, wherein the thickness of the aluminum layer (22) is 0.03-0.06 μm; the thickness of the PET film layer (4) is 100-300 μm; the thickness of the first antistatic coating (1) and the second antistatic coating (5) is 1-3 μm each; and the thickness of the conductive adhesive layer (3) is 2-8 μm.

7. A method for preparing a sheet-fed printing material composited with antistatic PET aluminized film and PET film as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) The PET base film layer (21) is subjected to corona treatment, and an aluminum layer (22) is deposited on one side surface of the PET base film layer (21) under vacuum conditions by vacuum evaporation to obtain a PET aluminum-coated film layer (2). (2) Mix the raw materials of the water-based antistatic varnish coating evenly to obtain the water-based antistatic varnish coating liquid; apply the water-based antistatic varnish coating liquid to the other side surface of the PET base film layer (21) and the other side surface of the PET film layer (4), and dry and cure to form the first antistatic coating (1) and the second antistatic coating (5). (3) Mix the raw materials of the conductive adhesive layer (3) evenly to obtain a conductive adhesive; apply the conductive adhesive to the surface of the aluminum layer (22) or the other side of the PET film layer (4), and after pre-drying, bond the PET aluminum film layer (2) to the PET film layer (4), and cure the conductive adhesive by curing. (4) After static electricity elimination treatment, cut into flat sheets according to specifications.

8. The method for preparing the antistatic PET aluminized film and PET film composite sheet printing material according to claim 7, characterized in that, In step (1), the PET base film layer (21) is subjected to corona treatment, and the surface tension reaches 42-48 dyn / cm; the aluminum layer (22) is deposited by vacuum evaporation, and the vacuum degree is not less than 1.0×10⁻²Pa.

9. The method for preparing the antistatic PET aluminized film and PET film composite sheet printing material according to claim 7, characterized in that, Step (2) Apply the water-based antistatic varnish coating liquid using the rod coating method, gravure coating method or micro-gravure coating method. The coating amount is 3-8 g / m² on a wet basis. After coating, adopt a segmented drying process: preheat at 60℃ for 1-3 min, main drying at 80℃ for 1-3 min, and curing at 100℃ for 1-3 min.

10. The method for preparing the antistatic PET aluminized film and PET film composite sheet printing material according to claim 7, characterized in that, In step (3), a dry composite process is used for bonding. The coating amount of the conductive adhesive is 3-10 g / m² on a dry basis, the pre-drying temperature is 60-100℃, the bonding pressure is 3-6 kg / cm², the bonding speed is 10-30 m / min, the curing temperature is 40-60℃, and the curing time is 24-72 hours.

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