A flexographic hanging plate and methods of making and using the same

Abstract

The present application provides a kind of flexible version of mounting plate base and its preparation method and use method, a kind of flexible version of mounting plate base, the flexible version of mounting plate base is sequentially substrate, pressure-sensitive adhesive layer and release material protective layer from bottom to top.Both solve the size deformation of the foam mounting tape stuck on the roller during repeated use, and various defects such as lifting and misalignment, and overcome the deficiencies such as too much time consumption during the process of pasting double-sided tape on the back of the printing plate, difficulty in separating the printing plate and the plate base during secondary bonding, and adhesive residue when using traditional mounting plate base, which is beneficial to further improve the efficiency of flexographic plate making.

Description

Technical Field

[0001] This invention belongs to the field of printing equipment consumables in flexographic printing, specifically relating to a flexographic plate substrate and its preparation and usage methods. Background Technology

[0002] Flexographic printing typically uses highly fluid, environmentally friendly water-based inks and UV inks, making it a relatively environmentally friendly printing method. During printing, the ink is first transferred to the printing plate roller via an anilox roller, contacting the image areas on the printing plate surface to ensure even and stable ink application. Then, the impression roller applies printing pressure, transferring the ink from the printing plate to the substrate. Finally, drying completes the printing process. Precisely positioning the prepared flexible resin printing plate with the image is crucial in this process.

[0003] Currently, there are three main methods for mounting printing plates in flexographic printing. One is the self-adhesive plate roller developed by companies like Twinlock, where the roller surface has its own adhesive material, allowing the printing plate to be directly attached to the self-adhesive plate roller. The second method involves pre-applying flexographic double-sided tape to the printing press roller, and then attaching the printing plate to the roller before printing. The third method uses a plate mounting base, where the design and text positions are marked on the plate mounting base, and then the user applies double-sided tape to the back of the prepared printing plate and attaches it to the corresponding position on the plate mounting base.

[0004] Self-adhesive printing rollers are a relatively new printing plate application process. They involve attaching a layer of foam padding and a special adhesive material to the surface of the original printing roller (which can be a sleeve or metal roller). This material itself is adhesive, so the printing plate can be directly fixed to the roller without the need for double-sided tape. The main advantages of this method are: users spend relatively less time on plate application and removal; the adhesive material on the roller surface can be reused after cleaning; registration accuracy is relatively higher; and storage conditions are simple, making it suitable for frequent printing plate changes. However, there are also some significant disadvantages. The cleaning process for the roller surface is relatively cumbersome; moreover, self-adhesive rollers are expensive, and if the surface is damaged after a certain period of repeated use, it will quickly lose its adhesiveness, resulting in relatively high replacement costs.

[0005] Applying double-sided tape to a dedicated printing roller is a traditional flexographic printing process, similar to the self-adhesive roller process mentioned above. Foam padding and double-sided tape are pre-applied to the printing roller, giving the roller surface an adhesive feel. The prepared flexographic printing plate can then be directly applied according to the specified positions. After printing, the double-sided tape on the roller retains its good adhesion even after the printing plate is removed, allowing for repeated use. The advantage of this method is high registration accuracy, making it suitable for simple product types and large print runs of a single product, especially for printing with flexographic plates thicker than 2.84mm. However, during repeated plate removal and replacement, the tape may be pulled off the sleeve or misaligned, affecting its reusability and production efficiency. Furthermore, this type of double-sided tape also has a relatively high cost.

[0006] Using flexographic printing plates with a film base is another common process for plate mounting. Currently, common flexographic printing plates with a film base mainly consist of two connected parts: a mounting strip and a film base. Before use, the pattern outline is pre-made on the film base using a flexographic typesetting and marking machine, and the positioning is confirmed. After the plate is made, double-sided tape is applied to the back of the plate, and then the pattern on the film base is mounted. The mounting strip is then used to fix it to the printing plate roller. The advantages of this mounting method are: relatively low cost, relatively convenient operation after printing (the printing plate and the film base can be removed as a single unit), and easy storage. However, there are also some disadvantages: ① The process of applying double-sided tape to the back of the printing plate takes a considerable amount of time; ② The double-sided tape used for mounting is very sticky, and if the adhesion between the printing plate and the pattern outline is inaccurate, it is difficult to separate the printing plate and the film base when it needs to be peeled off and re-attached, and there is often residue on the back. Summary of the Invention

[0007] To address the aforementioned issues, this invention provides a flexible plate mounting substrate, its preparation method, and its application method. This solution resolves various defects and problems associated with repeated use of foam mounting tape adhered to rollers, such as dimensional deformation, lifting, and misalignment. Furthermore, it overcomes the shortcomings of traditional mounting substrates, including excessive time consumption during the application of double-sided tape to the back of the printing plate, difficulty in separating the printing plate from the substrate during secondary bonding, and adhesive residue. This invention is beneficial for further improving the efficiency of flexographic plate making.

[0008] The object of the present invention is achieved in the following manner: a flexible plate mounting base, wherein the flexible plate mounting base comprises, from bottom to top, a substrate, a pressure-sensitive adhesive layer and a release material protective layer.

[0009] Hanging strips (4) are provided on the lower surfaces of both sides of the substrate (1).

[0010] The substrate is a plastic sheet with a thickness of 100-300μm. The material of the plastic sheet is any one of polyethylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, and polyimide.

[0011] The thickness of the plastic sheet base is 125um-250um, and the plastic sheet base is polyethylene terephthalate or polypropylene extruded using a twin-screw extrusion process.

[0012] The thickness of the pressure-sensitive adhesive layer is 1-30μm; the thickness of the release material protective layer is 10-50μm.

[0013] The thickness of the pressure-sensitive adhesive layer is 3-15um.

[0014] The release material protective layer is made of at least one of the following: film, release paper, non-woven fabric, and foam; the pressure-sensitive adhesive layer is made of one of the following: rubber type, vinyl ether type, silicone type, acrylate type, or isoprene type.

[0015] The material of the rubber-type pressure-sensitive adhesive layer is at least one of natural rubber, thermoplastic rubber, and copolymer rubber; the acrylate-type pressure-sensitive adhesive layer includes at least one polymer of polyacrylate, polyolefin, and vinyl aromatic block copolymer.

[0016] An acrylic pressure-sensitive adhesive layer comprising at least one polyacrylate, wherein the at least one polyacrylate component comprises at least 70% of the weight of the relevant layer, and also comprising acrylic acid, monomers, tackifying resins, and crosslinking agents.

[0017] The preparation method of the flexographic plate substrate is as follows: the raw material of the pressure-sensitive adhesive layer is first coated on the substrate, dried at 110-116℃ for 48h~72h to form a pressure-sensitive adhesive layer, and then a release material protective layer is applied and the plate is wound up.

[0018] The method of using the flexographic plate mounting base is as follows: After removing the release material protective layer, the back of the support body of the flexographic plate after plate making is tightly bonded to the mounting base through the pressure-sensitive adhesive layer. After bonding, the adhesion force between the plate support body and the mounting base is greater than or equal to 10N / 1.5cm and less than or equal to 30N / 1.5cm.

[0019] Compared with existing technologies, the plate-mounting substrate provided by this invention not only solves the various defects and problems of foam plate-mounting tape stuck on rollers during repeated use, such as size deformation, lifting, and misalignment, but also overcomes the shortcomings of traditional plate-mounting substrates, such as excessive time consumption in the process of pasting double-sided tape on the back of the printing plate, difficulty in separating the printing plate and the substrate during secondary bonding, and adhesive residue, which are conducive to further improving the efficiency of flexographic plate making.

[0020] The plate mounting substrate described in this invention has a pressure-sensitive adhesive layer on its surface. Therefore, when mounting the plate, there is no need to spend time applying double-sided tape to the back of the printing plate. Only the release material protective layer on the pressure-sensitive adhesive layer of the substrate needs to be peeled off. In addition, the material of the aforementioned plate mounting substrate is very similar to that of the support substrate used in the production of flexographic plates. Compared with the effect of double-sided tape used for plate mounting, the pressure-sensitive adhesive layer has a more moderate adhesive strength, and there is less adhesive residue on the plate surface after secondary separation. Therefore, after mounting, the adhesion between the plate mounting substrate and the flexographic support is excellent, ensuring that the printing plate will not fall off during long-term use. At the same time, because the adhesive strength of the pressure-sensitive adhesive layer is more moderate and there is less adhesive residue on the plate surface after secondary separation, it is also easy to separate the printing plate support and the plate mounting substrate, which is beneficial for quick correction of inaccurate mounting. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the flexible plate mounting substrate of the present invention.

[0022] Figure 2 This is a schematic diagram of the structure of the flexible plate mounting base with hanging strips of the present invention. Detailed Implementation

[0023] The present invention will now be described in detail with reference to specific embodiments. It should be noted that these embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above description of the present invention.

[0024] like Figure 1 and Figure 2 As shown, a flexible plate mounting base is characterized in that: the flexible plate mounting base consists of a substrate 1, a pressure-sensitive adhesive layer 2, and a release material protective layer 3 from bottom to top.

[0025] Hanging strips 4 are provided on the lower surfaces of both sides of the substrate 1.

[0026] The substrate is a plastic sheet with a thickness of 100-300 μm, and the plastic sheet is any one of polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polyethylene naphthalate (PEN), polyethylene (PE), polypropylene (PP), and polyimide (PI). Preferably, it is polyethylene terephthalate (PET) or polypropylene (PP) extruded using a twin-screw extrusion process.

[0027] The thickness of the plastic sheet base is 125um-250um, and the plastic sheet base is polyethylene terephthalate or polypropylene extruded using a twin-screw extrusion process.

[0028] The thickness of the pressure-sensitive adhesive layer is 1-30 μm; preferably, the thickness of the pressure-sensitive adhesive layer is 3-15 μm.

[0029] If the adhesive coating is too thin, the bonding strength between the printing plate and the mounting base cannot be guaranteed, which can easily lead to the edges of the printing plate lifting or even the entire plate detaching from the mounting base at some stage, such as before, during, or after printing, affecting the printing process or the normal use of the printing plate. If the adhesive coating is too thick, the printing plate will be subjected to continuous pressure and high temperature during the printing process. Under these conditions, the pressure-sensitive adhesive layer will melt and soften, resulting in greater fluidity and causing the printing plate to shift or misalign, thus failing to achieve the expected printing effect. Moreover, a thicker adhesive coating will also increase product costs.

[0030] The thickness of the release material protective layer is 10-50μm.

[0031] The release material protective layer is made of at least one of the following: film, release paper, non-woven fabric, and foam. For film-type release material protective layers, it can be any one of polypropylene (PP), polyethylene (PE), polyester (PET), nylon (PA), and polyvinyl chloride (PVC). Polyethylene terephthalate (PET) or nylon (PA) is preferred. The hanging strip can be made of PVC.

[0032] The pressure-sensitive adhesive layer is made of one of the following materials: rubber-based, vinyl ether-based, silicone-based, acrylate-based, or isoprene-based. Rubber-based or acrylate-based pressure-sensitive adhesives are preferred.

[0033] The material of the rubber-type pressure-sensitive adhesive layer is at least one of natural rubber, thermoplastic rubber, and copolymer rubber; thermoplastic rubber or copolymer butyl rubber is preferred.

[0034] Acrylic pressure-sensitive adhesive layers include at least one polymer from the group consisting of polyacrylate, polyolefin, and vinyl aromatic block copolymer.

[0035] The acrylic pressure-sensitive adhesive layer is a polyacrylate pressure-sensitive adhesive layer, which contains at least one polyacrylate, and the at least one polyacrylate component accounts for at least 70% of the weight of the relevant layer, and also contains acrylic acid, monomers, tackifying resins, and crosslinking agents. Specifically, this formulation is the same as that in CN114089603A. The pressure-sensitive adhesive layer formulations in Examples 1-3 of CN114089603A can all be used in this application.

[0036] The preparation method of the flexographic plate substrate is as follows: the coating liquid prepared from the raw materials of the pressure-sensitive adhesive layer is first coated on the substrate 1, dried at 110-116℃ for 48h~72h to form the pressure-sensitive adhesive layer 2, and then the release material protective layer 3 is applied and rolled up.

[0037] Depending on the actual application requirements, cutting processes such as rubbing marks and rubbing lines can be added to the surface of the release material protective layer 3 in advance to facilitate the removal of the protective layer.

[0038] The method of using the flexographic plate holder is as follows: After removing the release material protective layer, the back of the flexographic plate support, after plate making, is tightly bonded to the plate holder using a pressure-sensitive adhesive layer. After bonding, the adhesion between the plate support and the plate holder is greater than or equal to 10N / 1.5cm and less than or equal to 30N / 1.5cm. This ensures that the plate and plate holder do not detach during high-speed printing and can be stored and used for a long time. Furthermore, there is relatively little adhesive residue left on the plate surface after the secondary separation, and it facilitates the secondary separation between the plate support and the plate holder, which is beneficial for quick correction of misalignment.

[0039] Compared with existing technologies, the plate-mounting substrate provided by this invention not only solves the various defects and problems of foam plate-mounting tape stuck on rollers during repeated use, such as size deformation, lifting, and misalignment, but also overcomes the shortcomings of traditional plate-mounting substrates, such as excessive time consumption in the process of pasting double-sided tape on the back of the printing plate, difficulty in separating the printing plate and the substrate during secondary bonding, and adhesive residue, which are conducive to further improving the efficiency of flexographic plate making. Specific Implementation

[0040] The pressure-sensitive adhesive layer 2 is a polyacrylate-type pressure-sensitive adhesive layer. Specifically, it is prepared by copolymerizing 70g of polymethacrylate (Sigma-Aldrich), 15g of isooctyl acrylate, 12g of acrylic acid, 1.0g of benzoyl peroxide, and 80g of acetone / isopropanol (85:15) in a reaction flask to obtain a copolymer. Then, 15g of rosin-modified resin (Arakawa Chemical) is added, and the mixture is mixed to obtain a pressure-sensitive adhesive coating solution. The coating solution is applied to the substrate 1 through a single-screw extruder, and then dried at 110-160℃ for 48 hours to form a pressure-sensitive adhesive layer. The thickness of the dried pressure-sensitive adhesive layer 2 is 3-15µm.

[0041] Furthermore, before printing, the corresponding sheet base size is cut according to the size of the printing roller, and a suitable mounting strip is selected. The mounting sheet base and the mounting strip are permanently bonded together using ultrasonic cold bonding technology.

[0042] The method of using the printing plate base in this invention is as follows: First, use a flexographic typesetting and marking machine to pre-make the pattern outline on the printing plate base and make the positioning. Then, peel off the release material protective layer 3. Finally, paste the prepared printing plate directly onto the pressure-sensitive adhesive layer 2 to complete the plate pasting process.

[0043] The release film layer of the pressure-sensitive adhesive layer on the flexographic printing plate substrate in the above embodiments was removed. The thickness of the pressure-sensitive adhesive layer was 15 μm. The substrate 1 was made of PET. A support body (disclosed in CN200610107057.7) currently used in Lucky Flexographic Printing was directly bonded to simulate the plate-mounting state to create a sample. After plate-mounting, the adhesive strength between the printing plate support body and the flexographic printing plate substrate was measured according to "GB / T 2792-2014 Test Method for Peel Strength of Adhesive Tape". Three 15mm*200mm plates were cut in parallel using a cutting machine. A BLD-200S electronic peel tester (Jinan Langguang Electromechanical Technology Co., Ltd.) was used to peel the plates at a constant speed (200mm / min) at a 180° angle. This measured value was taken as the adhesive force between the flexographic printing plate and the flexographic printing plate substrate. The results of the three parallel samples are shown in Table 1 below. Table 1 Adhesion strength in the examples In addition to the evaluation methods mentioned above, the plate base described in this invention can also be evaluated by the following methods: After the prepared flexographic printing plate support is attached to the plate base with its own adhesive layer in this invention, it is directly printed on the printing press. More than 200,000 cartons are printed, and the adhesion between the support and the printing roller and the quality of the printed products are observed during printing, such as whether the pattern is accurately aligned with the plate and whether any offset occurs.

[0044] Compared to traditional plate-mounting methods, the self-adhesive flexographic printing plate base described in this invention eliminates the need for double-sided tape during printing, saving significant labor and time costs. The adhesion between the printing plate support and the plate base is greater than or equal to 10N / 1.5cm and less than or equal to 30N / 1.5cm, ensuring that the printing plate does not peel off or detach completely during printing. Furthermore, it overcomes several shortcomings of traditional plate bases, such as the time-consuming process of applying double-sided tape to the back of the printing plate, difficulties in separating the printing plate from the base when secondary bonding is necessary, and adhesive residue, effectively improving the plate-making efficiency of flexographic printing.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. It should be noted that for those skilled in the art and any person skilled in the art, any equivalent substitutions or changes made to the technical solution and inventive concept of the present invention without departing from the overall concept of the present invention, as well as any changes and improvements made, should also be considered within the scope of protection of the present invention.

Claims

1. A flexible plate mounting substrate, characterized in that: The flexible plate base consists of a substrate (1), a pressure-sensitive adhesive layer (2), and a release material protective layer (3) from bottom to top. Hanging strips (4) are provided on the lower surfaces of both sides of the substrate (1). The substrate is a plastic sheet base with a thickness of 100-300μm. The material of the plastic sheet base is any one of polyethylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, and polyimide. Polymethyl methacrylate (Sigma) 70g, isooctyl acrylate 15g, acrylic acid 12g, benzoyl peroxide 1.0g, and acetone / isopropanol (85:15) 80g were copolymerized in a reaction flask to obtain a copolymer. Then, rosin-modified resin (Arakawa Chemical) 15g was added and mixed to obtain a pressure-sensitive adhesive coating solution. The coating solution was applied to the substrate through a single screw extruder and then dried at 110-160℃ for 48h to form a pressure-sensitive adhesive layer. The thickness of the pressure-sensitive adhesive layer after drying is 3-15μm. The back of the support of the flexographic plate is tightly bonded to the mounting plate base through the pressure-sensitive adhesive layer. After bonding, the adhesion force between the plate support and the mounting plate base is greater than or equal to 10N / 1.5cm and less than or equal to 30N / 1.5cm.

2. The flexible plate mounting substrate according to claim 1, characterized in that: The thickness of the release material protective layer is 10-50μm.

3. The flexible plate mounting substrate according to claim 1, characterized in that: The protective layer of the release material is made of at least one of the following: film, release paper, non-woven fabric, and foam.

4. The flexible plate mounting substrate according to claim 3, characterized in that: The thickness of the plastic sheet base is 125μm-250μm, and the plastic sheet base is polyethylene terephthalate or polypropylene extruded using a twin-screw extrusion process.

5. The preparation method of the flexible plate mounting substrate according to any one of claims 1-4 is as follows: the raw material of the pressure-sensitive adhesive layer is first coated on the substrate (1), dried at 110-116℃ for 48h~72h to form a pressure-sensitive adhesive layer (2), and then a release material protective layer (3) is applied and rolled up.

6. The method of using the flexible plate mounting base according to any one of claims 1-4 is as follows: After removing the release material protective layer, the back of the support body of the flexible plate material after plate making is tightly bonded to the mounting base through the pressure-sensitive adhesive layer. After bonding, the adhesion force between the plate material support body and the mounting base is greater than or equal to 10N / 1.5cm and less than or equal to 30N / 1.5cm.

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