Etching process of screen cloth for silk screen

Abstract

The application discloses an etching process of screen cloth for silk screen printing, and relates to the technical field of silk screen printing.The etching process of screen cloth for silk screen printing comprises the following steps: S1, taking a silk screen and a screen frame according to printing requirements, cleaning, drying, tightly fixing the cleaned silk screen on the screen frame, and adjusting the tension to 20N-25N; S2, uniformly coating a photosensitive glue on the surface of the silk screen, drying, and obtaining a photosensitive film; S3, preparing a positive film according to printing requirements, combining the positive film with the photosensitive film, exposing under iodine gallium lamp light, then soaking in water, cleaning, and drying to obtain a developed screen printing plate; S4, checking the developed screen printing plate, repairing the missing part, and drying after repairing; and S5, smearing a curing agent on the surface of the repaired screen printing plate, curing, and obtaining the screen cloth.The photosensitive glue prepared by the application has good thermal stability and developing effect, and the prepared screen cloth has higher resolution.

Description

Technical Field

[0001] This invention relates to the field of screen printing stencil technology, specifically an etching process for screen printing stencils. Background Technology

[0002] Screen printing is an ancient and widely used printing technique. The specific production method is to stretch the screen tightly on the frame, then coat the screen with photosensitive emulsion, attach the designed pattern film to the screen coated with photosensitive emulsion, and expose it. The exposed part of the photosensitive emulsion undergoes a photochemical reaction and solidifies, while the unexposed part is washed away with developing solution, thus obtaining the screen printing stencil.

[0003] Patent CN202310248841.3 discloses a mesh etching process, screen printing stencil, and application. Monomers are introduced into a polymer emulsion and a diazo photosensitizer to cause a cross-linking reaction and form an interpenetrating network structure. This enhances the cross-linking strength of the photosensitive film, thereby improving its water resistance, solvent resistance, and weather resistance to achieve higher resolution.

[0004] For screen printing plate making, the most important process is the preparation of photosensitive emulsion, which needs to have good thermal stability and high resolution. Therefore, we propose an etching process for screen printing stencils. Summary of the Invention

[0005] The purpose of this invention is to provide an etching process for screen printing stencils to solve the problems mentioned in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an etching process for screen printing stencils, comprising the following steps:

[0007] S1: Take the screen and frame according to the printing requirements, clean and dry them, stretch the cleaned screen tightly on the frame, and adjust the tension to 20N~25N;

[0008] S2: Coat the photosensitive emulsion evenly on the screen surface and dry it to obtain a photosensitive film;

[0009] S3: Prepare a positive film according to printing requirements, attach the positive film to the photosensitive film, expose it under an iodine gallium lamp, then soak and wash it in water, and dry it to obtain a developing screen.

[0010] S4: Inspect the developing screen, repair any missing parts, and dry after repair;

[0011] S5: Apply a curing agent to the repaired screen surface and cure it to obtain the mesh fabric.

[0012] Furthermore, in S2, the coating thickness of the photosensitive emulsion is 0.01mm~0.06mm.

[0013] Furthermore, in S1, the wire mesh is one of stainless steel wire mesh, polyester wire mesh, or nylon wire mesh.

[0014] Furthermore, in S2, the drying temperature is 40℃~50℃.

[0015] Furthermore, in S3, the exposure process conditions are: exposure power 1000W~1300W, lamp distance 0.5m~1.5m, and time 20s~60s.

[0016] Furthermore, in S5, the curing process conditions are: temperature 45℃~55℃, time 30min~60min.

[0017] Furthermore, the curing agent is one or a mixture of two of polyetheramine and hexamethylenediamine.

[0018] Furthermore, in S2, the photosensitive emulsion is prepared by the following process:

[0019] Step (1): Mix dopamine polymer, diazo resin and water, then add polyvinyl alcohol emulsion, stir for 5 min to 15 min, and let stand at room temperature in the dark for 30 min to 60 min to obtain mixture A;

[0020] Step (2): Add fluorinated acrylic monomer, functional acrylic monomer and initiator to mixture A, stir evenly at room temperature in the dark to obtain photosensitive emulsion.

[0021] Furthermore, in step (1), the mass ratio of dopamine polymer, diazo resin, water and polyvinyl alcohol emulsion is 10:(0.4~0.8):(0.5~1):(80~100).

[0022] Furthermore, in step (2), the mass ratio of mixture A, fluorinated acrylic monomer, functional acrylic monomer and initiator is 1: (0.5~1): (0.3~0.7): (0.04~0.08).

[0023] Furthermore, in step (2), the fluorinated acrylic monomer is one or a mixture of hexafluoroisopropyl methacrylate, trifluoroethyl methacrylate, dodecafluoroheptyl methacrylate, and tridecafluorooctyl methacrylate.

[0024] The functional acrylic monomers are one or more of hydroxyethyl methacrylate, diacetone acrylamide, N-hydroxymethylacrylamide, and ethyl acetoacetate methacrylate.

[0025] Furthermore, the dopamine polymer described in step (1) is prepared by the following process:

[0026] Glycidyl methacrylate was mixed with N,N-dimethylformamide and stirred until dissolved. 6-hydroxydopamine hydrochloride was added, and the mixture was subjected to a vacuum-argon purging process. This process was repeated three times, followed by heating to obtain a reaction solution. The reaction solution was then added dropwise to a 1 mol / L hydrochloric acid solution for precipitation. The precipitate was collected by centrifugation, washed, and dried for 24 hours to obtain the dopamine polymer.

[0027] Furthermore, the ratio of glycidyl methacrylate, N,N-dimethylformamide and 6-hydroxydopamine hydrochloride is (0.05~0.1) g : (4~8) mL : (0.1~0.3) g.

[0028] Furthermore, the process conditions for the heating reaction are: temperature 70℃~90℃, time 12h~24h.

[0029] Furthermore, the centrifugation process conditions are: rotation speed 6000 r / min~8000 r / min, time 3 min~5 min.

[0030] In the above technical solution, etching is performed through processes such as exposure, development, immersion, and cleaning to obtain the mesh fabric. By preparing a photosensitive emulsion with good thermal stability and good development effect, the resulting mesh fabric has a higher resolution.

[0031] First, the epoxy group of glycidyl methacrylate reacts with the amino group of 6-hydroxydopamine hydrochloride in a nucleophilic ring-opening reaction to generate a dopamine polymer containing double bonds and hydroxyl groups. Because diazo resin decomposes at room temperature or under light to produce diazo resin free radicals, if it is directly mixed with polyvinyl alcohol emulsion, the diazo resin free radicals react with the hydroxyl groups in the polyvinyl alcohol emulsion, which increases the viscosity, reduces the photochemical reaction, and makes it difficult to wash and develop the screen. However, since the dopamine polymer contains hydroxyl groups, mixing it with diazo resin first allows the diazo resin free radicals to react with the hydroxyl groups of the dopamine polymer first, inhibiting the reaction between the diazo resin free radicals and the polyvinyl alcohol emulsion, extending the shelf life of the photosensitive emulsion, and improving the thermal stability of the photosensitive emulsion. The photosensitive film formed after drying has a good development effect.

[0032] Mixture A contains double bonds. When mixed with fluorinated acrylic monomers, functional acrylic monomers, and an initiator, a polymerization reaction occurs, forming a cross-linked network. This enhances the solvent resistance and weather resistance of the photosensitive film. The functional acrylic monomers have a slow cross-linking speed, preventing the photosensitive agent from undergoing excessive cross-linking during drying, which could lead to an overly high degree of cross-linking between the adhesive layers and affect the adhesion strength between the photosensitive adhesive and the screen. The fluorinated acrylic monomers contain fluorine segments, which have hydrophobic properties, giving the photosensitive adhesive a certain degree of water resistance. The fluorine segments also have strong electronegativity, which can further optimize the structure of the cross-linked network and enhance the photosensitivity of free radicals, thereby improving the edge clarity of the photosensitive film on the screen and resulting in higher screen printing precision.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. First, glycidyl methacrylate reacts with 6-hydroxydopamine hydrochloride to generate a dopamine polymer containing double bonds and hydroxyl groups. Then, it is mixed with diazo resin. The hydroxyl groups react with the free radicals of the diazo resin first, and then it is mixed with polyvinyl alcohol emulsion. This can inhibit the reaction between the free radicals of the diazo resin and the polyvinyl alcohol emulsion, prevent the viscosity from being too high, and avoid affecting the photochemical reaction. To a certain extent, it can extend the shelf life of the photosensitive emulsion, improve the thermal stability of the photosensitive emulsion, and the photosensitive film formed after drying has a good development effect.

[0035] 2. Through the polymerization reaction of the double bonds in mixture A with fluorinated acrylic monomers, functional acrylic monomers, and initiators, a cross-linked network is formed, improving the solvent resistance and weather resistance of the photosensitive film. The slow cross-linking speed of the functional acrylic monomers prevents excessively rapid cross-linking during the drying process, which could affect the adhesion strength between the photosensitive emulsion and the screen. The fluorinated acrylic monomers contain fluorinated segments, which have hydrophobic properties, giving the photosensitive emulsion a certain degree of water resistance. The fluorinated segments also have strong electronegativity, which can further optimize the structure of the cross-linked network and improve the photosensitivity of free radicals, thereby improving the edge clarity of the photosensitive film on the screen and resulting in higher screen printing precision. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the following specific implementation,

[0038] Stainless steel wire mesh, 400 mesh, 1.5mm aperture, 0.025mm wire diameter, sourced from Anping County Hongda Hardware Wire Mesh Factory;

[0039] Glycidyl methacrylate, CAS number 106-91-2, is sourced from Jinan Century Tongda Chemical Co., Ltd.

[0040] N,N-Dimethylformamide, CAS number 68-12-2, is sourced from Shandong Junlong Chemical Co., Ltd.

[0041] 6-Hydroxydopamine hydrochloride, CAS number 28094-15-7, is sourced from Qiyuan (Guangdong) Pharmaceutical & Chemical Co., Ltd.

[0042] Hydrochloric acid solution, catalog number R27801, is derived from Yuanye Biotechnology;

[0043] Polyvinyl alcohol emulsion, model MY-100, is sourced from Dongguan Mingyu New Materials Co., Ltd.

[0044] Diazo resin, model SP-1400GK, is sourced from Shenyang China Printing Machinery Co., Ltd.

[0045] Hexafluoroisopropyl methacrylate, CAS number 3063-94-3, is sourced from Hubei Xingyan New Material Technology Co., Ltd.

[0046] Hydroxyethyl methacrylate, CAS number 868-77-9, is sourced from Shandong Langcheng Chemical Co., Ltd.

[0047] Azobisisobutyronitrile (AIBN), CAS number 78-67-1, is sourced from Shandong Taixi Chemical Co., Ltd.

[0048] Polyetheramine, model D4000, is sourced from Shandong Tonglan Chemical Co., Ltd.

[0049] Example 1: An etching process for screen printing stencils, comprising the following steps:

[0050] (1) Preparation of photosensitive emulsion:

[0051] Glycidyl methacrylate and N,N-dimethylformamide were mixed and stirred until dissolved. 6-hydroxydopamine hydrochloride was added, and the mixture was subjected to a vacuum-argon purging process, repeated three times. The reaction was heated to obtain a reaction solution. The reaction solution was added dropwise to a 1 mol / L hydrochloric acid solution for precipitation. The precipitate was collected by centrifugation, washed, and dried for 24 h to obtain the dopamine polymer. The ratio of glycidyl methacrylate, N,N-dimethylformamide, and 6-hydroxydopamine hydrochloride was 0.1 g: 8 mL: 0.3 g. The heating conditions were: temperature 90 °C, time 24 h; the centrifugation conditions were: speed 8000 r / min, time 5 min.

[0052] Step (1): Mix dopamine polymer, diazo resin and water, then add polyvinyl alcohol emulsion, stir for 15 min, and place at room temperature in the dark for 60 min to obtain mixture A; Step (2): Add hexafluoroisopropyl methacrylate, hydroxyethyl methacrylate and initiator to mixture A, stir evenly at room temperature in the dark to obtain photosensitive adhesive; In step (1), the mass ratio of dopamine polymer, diazo resin, water and polyvinyl alcohol emulsion is 10:0.8:1:100; In step (2), the mass ratio of mixture A, hexafluoroisopropyl methacrylate, hydroxyethyl methacrylate and initiator is 1:1:0.7:0.08;

[0053] (2) Preparation of mesh fabric:

[0054] S1: Take the screen and frame according to the printing requirements, clean and dry them, and stretch the cleaned screen tightly on the frame, adjusting the tension to 25N; S2: Apply photosensitive emulsion evenly to the screen surface, dry it, and obtain the photosensitive film; S3: Make a positive film according to the printing requirements, attach the positive film to the photosensitive film, expose it under an iodine gallium lamp, then soak it in water, clean it, and dry it to obtain the developing screen; S4: Inspect the developing screen, repair any missing parts, and dry it after repair; S5: Apply polyetheramine to the surface of the repaired screen, cure it, and obtain the screen fabric; In S2, the coating thickness of the photosensitive emulsion is 0.06mm; In S2, the drying temperature is 50℃; In S3, the exposure process conditions are: exposure power 1300W, lamp distance 1.5m, time 60s; In S5, the curing process conditions are: temperature 55℃, time 60min.

[0055] Example 2: An etching process for screen printing stencils, comprising the following steps:

[0056] (1) Preparation of photosensitive emulsion:

[0057] Glycidyl methacrylate and N,N-dimethylformamide were mixed and stirred until dissolved. 6-hydroxydopamine hydrochloride was added, and the mixture was subjected to a vacuum-argon purging process, repeated three times. The reaction was heated to obtain a reaction solution. The reaction solution was added dropwise to a 1 mol / L hydrochloric acid solution for precipitation. The precipitate was collected by centrifugation, washed, and dried for 24 h to obtain the dopamine polymer. The ratio of glycidyl methacrylate, N,N-dimethylformamide, and 6-hydroxydopamine hydrochloride was 0.07 g: 6 mL: 0.2 g. The heating reaction conditions were: temperature 80 °C, time 18 h; the centrifugation conditions were: speed 7000 r / min, time 4 min.

[0058] Step (1): Mix dopamine polymer, diazo resin and water, then add polyvinyl alcohol emulsion, stir for 10 min, and let stand at room temperature in the dark for 45 min to obtain mixture A; Step (2): Add hexafluoroisopropyl methacrylate, hydroxyethyl methacrylate and initiator to mixture A, stir evenly at room temperature in the dark to obtain photosensitive adhesive; In step (1), the mass ratio of dopamine polymer, diazo resin, water and polyvinyl alcohol emulsion is 10:0.6:0.7:90; In step (2), the mass ratio of mixture A, hexafluoroisopropyl methacrylate, hydroxyethyl methacrylate and initiator is 1:0.7:0.5:0.06;

[0059] (2) Preparation of mesh fabric:

[0060] S1: Take the screen and frame according to the printing requirements, clean and dry them, and stretch the cleaned screen tightly on the frame, adjusting the tension to 23N; S2: Apply photosensitive emulsion evenly to the screen surface, dry it, and obtain the photosensitive film; S3: Make a positive film according to the printing requirements, attach the positive film to the photosensitive film, expose it under an iodine gallium lamp, then soak it in water, clean it, and dry it to obtain the developing screen; S4: Inspect the developing screen, repair any missing parts, and dry it after repair; S5: Apply polyetheramine to the surface of the repaired screen, cure it, and obtain the screen fabric; In S2, the coating thickness of the photosensitive emulsion is 0.04mm; In S2, the drying temperature is 45℃; In S3, the exposure process conditions are: exposure power 1200W, lamp distance 1.0m, time 40s; In S5, the curing process conditions are: temperature 50℃, time 45min.

[0061] Example 3: An etching process for screen printing stencils, comprising the following steps:

[0062] (1) Preparation of photosensitive emulsion:

[0063] Glycidyl methacrylate and N,N-dimethylformamide were mixed and stirred until dissolved. 6-hydroxydopamine hydrochloride was added, and the mixture was subjected to a vacuum-argon purging process, repeated three times. The reaction was heated to obtain a reaction solution. The reaction solution was added dropwise to a 1 mol / L hydrochloric acid solution for precipitation. The precipitate was collected by centrifugation, washed, and dried for 24 h to obtain the dopamine polymer. The ratio of glycidyl methacrylate, N,N-dimethylformamide, and 6-hydroxydopamine hydrochloride was 0.1 g: 8 mL: 0.3 g. The heating conditions were: temperature 90 °C, time 24 h; the centrifugation conditions were: speed 8000 r / min, time 5 min.

[0064] Step (1): Mix dopamine polymer, diazo resin and water, then add polyvinyl alcohol emulsion, stir for 15 min, and place at room temperature in the dark for 60 min to obtain mixture A; Step (2): Add hexafluoroisopropyl methacrylate, hydroxyethyl methacrylate and initiator to mixture A, stir evenly at room temperature in the dark to obtain photosensitive adhesive; In step (1), the mass ratio of dopamine polymer, diazo resin, water and polyvinyl alcohol emulsion is 10:0.8:1:100; In step (2), the mass ratio of mixture A, hexafluoroisopropyl methacrylate, hydroxyethyl methacrylate and initiator is 1:1:0.7:0.08;

[0065] (2) Preparation of mesh fabric:

[0066] S1: Take the screen and frame according to the printing requirements, clean and dry them, and stretch the cleaned screen tightly on the frame, adjusting the tension to 25N; S2: Apply photosensitive emulsion evenly to the screen surface, dry it, and obtain the photosensitive film; S3: Make a positive film according to the printing requirements, attach the positive film to the photosensitive film, expose it under an iodine gallium lamp, then soak it in water, clean it, and dry it to obtain the developing screen; S4: Inspect the developing screen, repair any missing parts, and dry it after repair; S5: Apply polyetheramine to the surface of the repaired screen, cure it, and obtain the screen fabric; In S2, the coating thickness of the photosensitive emulsion is 0.06mm; In S2, the drying temperature is 50℃; In S3, the exposure process conditions are: exposure power 1300W, lamp distance 1.5m, time 60s; In S5, the curing process conditions are: temperature 45℃, time 30min.

[0067] Comparative Example 1: Compared with Example 1, without adding dopamine polymer during the preparation of the photosensitive emulsion, and with other conditions remaining unchanged, an etching process for a screen printing stencil includes the following steps:

[0068] (1) Preparation of photosensitive emulsion:

[0069] The diazo resin, water, and polyvinyl alcohol emulsion were mixed and stirred for 15 minutes. Then, hexafluoroisopropyl methacrylate, hydroxyethyl methacrylate, and an initiator were added. The mixture was stirred evenly at room temperature in the dark to obtain the photosensitive adhesive. The mass ratio of diazo resin, water, and polyvinyl alcohol emulsion was 0.8:1:100.

[0070] (2) Preparation of mesh fabric:

[0071] S1: Take the screen and frame according to the printing requirements, clean and dry them, and stretch the cleaned screen tightly on the frame, adjusting the tension to 25N; S2: Apply photosensitive emulsion evenly to the screen surface, dry it, and obtain the photosensitive film; S3: Make a positive film according to the printing requirements, attach the positive film to the photosensitive film, expose it under an iodine gallium lamp, then soak it in water, clean it, and dry it to obtain the developing screen; S4: Inspect the developing screen, repair any missing parts, and dry it after repair; S5: Apply polyetheramine to the surface of the repaired screen, cure it, and obtain the screen fabric; In S2, the coating thickness of the photosensitive emulsion is 0.06mm; In S2, the drying temperature is 50℃; In S3, the exposure process conditions are: exposure power 1300W, lamp distance 1.5m, time 60s; In S5, the curing process conditions are: temperature 55℃, time 60min.

[0072] Comparative Example 2: Compared with Example 1, without adding hexafluoroisopropyl methacrylate and hydroxyethyl methacrylate during the preparation of the photosensitive emulsion, and with other conditions remaining unchanged, an etching process for screen printing stencil cloth includes the following steps:

[0073] (1) Preparation of photosensitive emulsion:

[0074] Glycidyl methacrylate and N,N-dimethylformamide were mixed and stirred until dissolved. 6-hydroxydopamine hydrochloride was added, and the mixture was subjected to a vacuum-argon purging process, repeated three times. The reaction was heated to obtain a reaction solution. The reaction solution was added dropwise to a 1 mol / L hydrochloric acid solution for precipitation. The precipitate was collected by centrifugation, washed, and dried for 24 h to obtain the dopamine polymer. The ratio of glycidyl methacrylate, N,N-dimethylformamide, and 6-hydroxydopamine hydrochloride was 0.1 g: 8 mL: 0.3 g. The heating conditions were: temperature 90 °C, time 24 h; the centrifugation conditions were: speed 8000 r / min, time 5 min.

[0075] Step (1): Mix dopamine polymer, diazo resin and water, then add polyvinyl alcohol emulsion, stir for 15 min, and let stand at room temperature in the dark for 60 min to obtain mixture A; Step (2): Add initiator to mixture A, stir evenly at room temperature in the dark to obtain photosensitive emulsion; In step (1), the mass ratio of dopamine polymer, diazo resin, water and polyvinyl alcohol emulsion is 10:0.8:1:100; In step (2), the mass ratio of mixture A and initiator is 1:0.08;

[0076] (2) Preparation of mesh fabric:

[0077] S1: Take the screen and frame according to the printing requirements, clean and dry them, and stretch the cleaned screen tightly on the frame, adjusting the tension to 25N; S2: Apply photosensitive emulsion evenly to the screen surface, dry it, and obtain the photosensitive film; S3: Make a positive film according to the printing requirements, attach the positive film to the photosensitive film, expose it under an iodine gallium lamp, then soak it in water, clean it, and dry it to obtain the developing screen; S4: Inspect the developing screen, repair any missing parts, and dry it after repair; S5: Apply polyetheramine to the surface of the repaired screen, cure it, and obtain the screen fabric; In S2, the coating thickness of the photosensitive emulsion is 0.06mm; In S2, the drying temperature is 50℃; In S3, the exposure process conditions are: exposure power 1300W, lamp distance 1.5m, time 60s; In S5, the curing process conditions are: temperature 55℃, time 60min.

[0078] Comparative Example 3: Compared with Example 1, neither 6-hydroxydopamine hydrochloride nor hexafluoroisopropyl methacrylate and hydroxyethyl methacrylate were used, and all other conditions remained the same.

[0079] experiment:

[0080] Development effect test: Take the photosensitive emulsions obtained in Examples 1-3 and Comparative Examples 1-3, dry them at 50°C, and then bond the photosensitive film with the positive film. Expose the film under a 1300W iodine gallium lamp, then wash and develop it. Observe the development effect and water fastness, and record the results.

[0081] Resolution test: Take the mesh fabrics obtained in Examples 1-3 and Comparative Examples 1-3, use alumina ceramic as the substrate, print patterns of different resolutions on the substrate, observe the patterns, and test the minimum resolution for complete pattern.

[0082] The table below shows the test results for the photosensitive film's development effect, water fastness, and resolution.

[0083]

[0084] Based on the data in the table above, the following conclusions can be clearly drawn:

[0085] Compared with the photosensitive films in Examples 1-3 and Comparative Examples 1-3, the test results show that...

[0086] Compared with Example 1, Comparative Example 1 did not add dopamine polymer during the preparation of the photosensitive emulsion, resulting in poor development effect and excessively high water development fastness. This is because the dopamine polymer was first mixed with polyvinyl alcohol emulsion, which inhibited the reaction between diazo resin free radicals and polyvinyl alcohol emulsion, extended the shelf life of the photosensitive emulsion, and improved the thermal stability of the photosensitive emulsion. The photosensitive film formed after drying had a better development effect.

[0087] Compared to Example 1, Comparative Example 2, which did not add fluorinated acrylic monomers and functional acrylic monomers during photosensitive emulsion preparation, exhibited poor development results, higher water fastness, and a more significant decrease in resolution. This is because the slow cross-linking speed of functional acrylic monomers prevents the photosensitive agent from undergoing excessively rapid cross-linking during drying, which could lead to an excessively high degree of cross-linking between the emulsion layers and affect the adhesion strength between the photosensitive emulsion and the screen. Furthermore, the fluorinated segments possess strong electronegativity, which can further optimize the structure of the cross-linked network, enhance the photosensitivity of free radicals, and thus improve the edge clarity of the photosensitive film on the screen, resulting in higher screen printing precision.

[0088] Compared with Example 1, Comparative Example 3 does not use 6-hydroxydopamine hydrochloride, nor does it add fluorinated acrylic monomers or functional acrylic monomers, indicating that the process and materials used in this application can promote the improvement of the thermal stability of the photosensitive emulsion and the improvement of the screen development effect and resolution.

[0089] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. An etching process for screen printing stencils, characterized in that: Includes the following steps: S1: Take the screen and frame according to the printing requirements, clean and dry them, stretch the cleaned screen tightly on the frame, and adjust the tension to 20N~25N; S2: Coat the photosensitive emulsion evenly on the screen surface and dry it to obtain a photosensitive film; S3: Prepare a positive film according to printing requirements, attach the positive film to the photosensitive film, expose it under an iodine gallium lamp, then soak and wash it in water, and dry it to obtain a developing screen. S4: Inspect the developing screen and repair any missing parts; S5: Apply a curing agent to the repaired screen surface and cure it to obtain the mesh fabric; The photosensitive adhesive comprises the following components: dopamine polymer, diazo resin, polyvinyl alcohol emulsion, fluorinated acrylic monomer, and functional acrylic monomer; The dopamine polymer is prepared by the following process: Glycidyl methacrylate was mixed with N,N-dimethylformamide and stirred until dissolved. 6-hydroxydopamine hydrochloride was added, and the mixture was subjected to a vacuum-argon purging process. This process was repeated three times, followed by heating to obtain a reaction solution. The reaction solution was then added dropwise to a 1 mol / L hydrochloric acid solution for precipitation. The precipitate was collected by centrifugation, washed, and dried for 24 hours to obtain the dopamine polymer.

2. The etching process for a screen printing stencil as described in claim 1, characterized in that: In S2, the coating thickness of the photosensitive emulsion is 0.01mm~0.06mm.

3. The etching process for a screen printing stencil according to claim 1, characterized in that: In S3, the exposure process conditions are: exposure power 1000W~1300W, lamp distance 0.5m~1.5m, and time 20s~60s.

4. The etching process for a screen printing stencil as described in claim 1, characterized in that: The photosensitive emulsion is prepared by the following process: Step (1): Mix dopamine polymer, diazo resin and water, then add polyvinyl alcohol emulsion, stir for 5 min to 15 min, and let stand at room temperature in the dark for 30 min to 60 min to obtain mixture A; Step (2): Add fluorinated acrylic monomer, functional acrylic monomer and initiator to mixture A, stir evenly at room temperature in the dark to obtain photosensitive emulsion.

5. The etching process for a screen printing stencil as described in claim 1, characterized in that: The ratio of glycidyl methacrylate, N,N-dimethylformamide and 6-hydroxydopamine hydrochloride is (0.05~0.1) g : (4~8) mL : (0.1~0.3) g.

6. The etching process for a screen printing stencil as described in claim 1, characterized in that: The centrifugation process conditions are: rotation speed 6000 r / min~8000 r / min, time 3 min~5 min.

7. The etching process for a screen printing stencil as described in claim 4, characterized in that: In step (1), the mass ratio of dopamine polymer, diazo resin, water and polyvinyl alcohol emulsion is 10: (0.4~0.8): (0.5~1): (80~100).

8. The etching process for a screen printing stencil as described in claim 4, characterized in that: In step (2), the mass ratio of mixture A, fluorinated acrylic monomer, functional acrylic monomer and initiator is 1: (0.5~1): (0.3~0.7): (0.04~0.08).

9. The etching process for a screen printing stencil according to claim 4, characterized in that: In step (2), the fluorinated acrylic monomer is one or a mixture of hexafluoroisopropyl methacrylate, trifluoroethyl methacrylate, dodecafluoroheptyl methacrylate, and tridecafluorooctyl methacrylate. The functional acrylic monomers are one or more of hydroxyethyl methacrylate, diacetone acrylamide, N-hydroxymethylacrylamide, and ethyl acetoacetate methacrylate.

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