A screen printing plate surface coating process

Abstract

This invention belongs to the printing field, particularly the B41C1 / 14 field, and more specifically relates to a screen printing plate surface coating process. The screen printing plate surface coating process includes screen stretching, wire removal, cleaning, film application, adhesive spraying, baking, laser engraving, screen inspection, and packaging. The adhesive used in the adhesive spraying step is prepared from diacid anhydrides, diamines, and polar solvents. Since a squeegee needs to contact the screen surface during printing, the numerous contacts easily cause wear, reducing the number of times the screen can be reprinted. This invention, through a specific screen printing plate surface coating process, can effectively increase the number of times the screen can be reprinted, thereby significantly reducing the printing cost.

Description

Technical Field

[0001] This invention belongs to the printing field, particularly to the B41C1 / 14 field, and more specifically to a screen printing surface spraying process. Background Technology

[0002] The conventional method for treating the surface of a screen printing plate is as follows: the screen fabric is stretched and bonded to a frame, then coated after cleaning, and finally laser-engraved to form a pattern. Stainless steel screen printing plates consist of stainless steel mesh with different aperture sizes and a frame coated on the mesh. The most important considerations in screen printing plate preparation are cost and the photoelectric conversion efficiency in subsequent applications in batteries. Typically, one screen can print multiple solar cells. During screen printing, the squeegee contacts the screen surface many times, inevitably causing some wear. When wear is significant, the screen becomes damaged and unusable, requiring replacement and significantly increasing printing costs. Effectively extending the lifespan of the screen and reducing surface wear can save production costs.

[0003] The prior art CN209191458U discloses a screen printing plate that significantly increases the number of printing passes and allows for multiple reuses. This screen printing plate includes a first clamping plate and a second clamping plate, with a metal screen printing plate positioned between the first and second clamping plates. Grooves are provided on opposite sides of both the first and second clamping plates, and the two ends of the metal screen printing plate extend into these grooves and are press-fitted into them. A first baffle and a second baffle are provided on the other two sides of the metal screen printing plate, with their ends fixedly connected to the first and second clamping plates, respectively. This screen printing plate, through simple structural improvements, increases the number of printing passes; however, improving its printing lifespan solely through structural modifications is relatively limited. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a screen printing plate surface coating process, comprising at least the following steps:

[0005] S1. Wire Mesh Tension: Tensile the stainless steel wire mesh, fix it on a flat table, cut it to the required specifications, apply glue to the mesh frame, and fix the mesh fabric to the mesh frame;

[0006] S2. Removing steel wires: Place the stretched screen flat on the laser equipment and use the laser equipment to locally remove the steel wires on the screen;

[0007] S3. Cleaning: Apply cleaning agent to the mesh plate and perform ultrasonic cleaning to remove oil;

[0008] S4. Applying film: Apply PI film to the cleaned screen surface;

[0009] S5. Spraying adhesive: Place the screen with the PI film attached under the nano spraying equipment and spray adhesive evenly;

[0010] S6. Baking: Place the screen with the sprayed adhesive onto the baking mold to form a coating with the PI film;

[0011] S7. Laser engraving: Place the baked stencil on the laser engraving equipment with the PI film facing up and align it for laser engraving.

[0012] S8. Screen Inspection: Inspect the laser-engraved screen, including appearance, graphic requirements, tension, and total thickness.

[0013] S9. Packaging: Pack the qualified screen printing plates.

[0014] Preferably, in the baking step, the baking temperature is 100-200℃ and the baking time is 30-60 minutes.

[0015] Preferably, the raw materials for preparing the adhesive are diacid anhydride, diamine and solvent.

[0016] Preferably, the dicarboxylic acid anhydride is a dicarboxylic acid anhydride containing a benzene ring.

[0017] Preferably, the benzene-containing dicarboxylic acid anhydride includes one or more of pyromellitic dianhydride, 3,3',4,4'-diphenyl ether dianhydride, and 4,4'-biphenyl ether dianhydride.

[0018] More preferably, the molecule of the benzene-containing dicarboxylic acid anhydride contains an ether bond.

[0019] More preferably, the benzene-containing dicarboxylic acid anhydride includes one or more of 3,3',4,4'-diphenyl ether dianhydride and 4,4'-biphenyl ether dianhydride.

[0020] Preferably, the diamine is a diamine containing a benzene ring.

[0021] More preferably, the diamine containing a benzene ring includes one or more of diphenyl ether diamine, p-phenylenediamine, and 4,4'-biphenylenediamine.

[0022] More preferably, the molecule of the benzene-ring-containing diamine contains an ether bond.

[0023] More preferably, the benzene-containing diamine includes diphenyl ether diamine.

[0024] Preferably, the solvent is either a polar solvent or a non-polar solvent.

[0025] More preferably, the solvent is a polar solvent.

[0026] More preferably, the polar solvent is one or more of N-methylpyrrolidone, phenol, methylphenol, N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, and dichloromethane.

[0027] Preferably, the preparation steps of the adhesive are as follows: mixing diacid anhydride, diamine and solvent, controlling the reaction temperature at 10-25℃, and stirring the reaction for 24-48 hours to obtain the adhesive.

[0028] Preferably, the molar ratio of the dicarboxylic acid anhydride to the diamine is (0.85-1):(0.99-1).

[0029] Preferably, the total amount of the dicarboxylic acid anhydride and diamine is 10-45 wt% of the total mass of the reaction system. Attached Figure Description

[0030] Figure 1 This is an enlarged schematic diagram of the screen printing plate obtained in Example 1.

[0031] Figure 2 This is an enlarged schematic diagram of the screen print obtained in Comparative Example 1.

[0032] Beneficial effects

[0033] (i) Since the screen needs to be contacted by a squeegee during printing, the screen surface is easily worn due to the large number of contacts, which reduces the number of times the screen can be reprinted and its service life. In this invention, a specific screen surface spraying process can effectively increase the number of times the screen can be reprinted, thereby significantly reducing the printing cost of the screen.

[0034] (II) The core of reducing screen wear in this invention lies in the use of a specific adhesive. In this invention, a dicarboxylic acid anhydride containing a benzene ring, a diamine containing a benzene ring, and a polar solvent are selected as raw materials for the adhesive. The dicarboxylic acid anhydride and the diamine containing a benzene ring contain rigid groups of benzene rings in their molecules. The dehydration polymerization of the two can improve the hardness of the adhesive and effectively protect the screen surface when the squeegee contacts the screen surface.

[0035] (III) The inventors have discovered that when using diacid anhydrides containing benzene rings and diamines containing benzene rings as raw materials for adhesives, the stability of the adhesive can be further improved. Since the polymer molecules in the adhesive contain ether bonds in their main chain structure and have amine and anhydride groups at the end groups, the ether bonds have low cohesive energy and are easy to rotate. Therefore, the adhesive has excellent low-temperature flexibility and hydrolysis resistance, and can adhere more stably to the screen surface, effectively protecting the steel wire from damage caused by the scraper. If the molecule does not contain ether bonds, the synthesized adhesive will have low bonding strength after high-temperature curing, and it will be difficult to effectively adhere to the stainless steel wire of the screen to protect the screen surface.

[0036] (iv) In this invention, the raw materials for preparing the adhesive do not include any catalysts or other functional additives. It is only necessary to mix and stir the raw materials, diacid anhydride, diamine and polar solvent in a certain mass ratio. This can effectively reduce the cost of the reaction and avoid the catalyst of the product from corroding the stainless steel wire of the screen, thus effectively improving the service life of the screen.

[0037] (v) In this invention, before spraying the adhesive, a layer of polyimide (PI) film is first applied to the surface of the screen, and then the adhesive is sprayed. After spraying, the screen is baked at a high temperature of 100-200°C to generate a high adhesion between the adhesive layer and the PI film layer. The two work together to firmly adhere to the surface of the screen and increase the number of times the screen can be printed. Detailed Implementation

[0038] Example 1

[0039] This embodiment provides a screen printing plate surface coating process, specifically comprising the following steps:

[0040] S1. Wire Mesh Tension: Tensile the stainless steel wire mesh, fix it on a flat table, cut it to the required specifications, apply glue to the mesh frame, and fix the mesh fabric to the mesh frame;

[0041] S2. Removing steel wires: Place the stretched screen flat on the laser equipment and use the laser equipment to locally remove the steel wires on the screen;

[0042] S3. Cleaning: Apply cleaning agent to the mesh plate and perform ultrasonic cleaning to remove oil;

[0043] S4. Applying film: Apply PI film to the cleaned screen surface;

[0044] S5. Spraying adhesive: Place the screen with the PI film attached under the nano spraying equipment and spray adhesive evenly;

[0045] S6. Baking: Place the screen with the sprayed adhesive on the baking mold and bake it to form a coating with the PI film. The baking temperature is 200℃ and the baking time is 60min.

[0046] S7. Laser engraving: Place the baked stencil on the laser engraving equipment with the PI film facing up and align it for laser engraving.

[0047] S8. Screen Inspection: Inspect the laser-engraved screen, including appearance, graphic requirements, tension, and total thickness.

[0048] S9. Packaging: Pack the qualified screen printing plates.

[0049] The cleaning agent and PI film mentioned are commercially available products.

[0050] The adhesive is prepared from 3,3',4,4'-diphenyl ether dianhydride, diphenyl ether diamine, and the polar solvent N,N-dimethylformamide. The molar ratio of 3,3',4,4'-diphenyl ether dianhydride and diphenyl ether diamine is 0.85:1; the total amount of 3,3',4,4'-diphenyl ether dianhydride and diphenyl ether diamine accounts for 30 wt% of the reaction system. The preparation steps of the adhesive are as follows: mixing the dianhydride, diamine, and solvent, controlling the reaction temperature at 25°C, and stirring for 40 hours to obtain the adhesive.

[0051] An enlarged view of the screen print obtained in this example is shown below. Figure 1 As shown.

[0052] Example 2

[0053] This embodiment provides a screen printing plate surface coating process, specifically comprising the following steps:

[0054] S1. Wire Mesh Tension: Tensile the stainless steel wire mesh, fix it on a flat table, cut it to the required specifications, apply glue to the mesh frame, and fix the mesh fabric to the mesh frame;

[0055] S2. Removing steel wires: Place the stretched screen flat on the laser equipment and use the laser equipment to locally remove the steel wires on the screen;

[0056] S3. Cleaning: Apply cleaning agent to the mesh plate and perform ultrasonic cleaning to remove oil;

[0057] S4. Applying film: Apply PI film to the cleaned screen surface;

[0058] S5. Spraying adhesive: Place the screen with the PI film attached under the nano spraying equipment and spray adhesive evenly;

[0059] S6. Baking: Place the screen with the sprayed adhesive on the baking mold and bake it to form a coating with the PI film. The baking temperature is 200℃ and the baking time is 60min.

[0060] S7. Laser engraving: Place the baked stencil on the laser engraving equipment with the PI film facing up and align it for laser engraving.

[0061] S8. Screen Inspection: Inspect the laser-engraved screen, including appearance, graphic requirements, tension, and total thickness.

[0062] S9. Packaging: Pack the qualified screen printing plates.

[0063] The cleaning agent and PI film mentioned are commercially available products.

[0064] The adhesive is prepared from 3,3',4,4'-diphenyl ether dianhydride, diphenyl ether diamine, and N,N-dimethylformamide. The molar ratio of 3,3',4,4'-diphenyl ether dianhydride and diphenyl ether diamine is 1:1; the total amount of 3,3',4,4'-diphenyl ether dianhydride and diphenyl ether diamine accounts for 40 wt% of the reaction system. The preparation steps of the adhesive are as follows: mixing the diacid anhydride, the diamine, and the solvent, controlling the reaction temperature at 25°C, and stirring the reaction for 48 hours to obtain the adhesive.

[0065] Example 3

[0066] This embodiment provides a screen printing plate surface coating process, specifically comprising the following steps:

[0067] S1. Wire Mesh Tension: Tensile the stainless steel wire mesh, fix it on a flat table, cut it to the required specifications, apply glue to the mesh frame, and fix the mesh fabric to the mesh frame;

[0068] S2. Removing steel wires: Place the stretched screen flat on the laser equipment and use the laser equipment to locally remove the steel wires on the screen;

[0069] S3. Cleaning: Apply cleaning agent to the mesh plate and perform ultrasonic cleaning to remove oil;

[0070] S4. Applying film: Apply PI film to the cleaned screen surface;

[0071] S5. Spraying adhesive: Place the screen with the PI film attached under the nano spraying equipment and spray adhesive evenly;

[0072] S6. Baking: Place the screen with the sprayed adhesive on the baking mold and bake it to form a coating with the PI film. The baking temperature is 200℃ and the baking time is 60min.

[0073] S7. Laser engraving: Place the baked stencil on the laser engraving equipment with the PI film facing up and align it for laser engraving.

[0074] S8. Screen Inspection: Inspect the laser-engraved screen, including appearance, graphic requirements, tension, and total thickness.

[0075] S9. Packaging: Pack the qualified screen printing plates.

[0076] The cleaning agent and PI film mentioned are commercially available products.

[0077] The adhesive is prepared from 4,4'-biphenyl ether dianhydride, diphenyl ether diamine, and N-methyl-pyrrolidone. The molar ratio of 3,3',4,4'-diphenyl ether dianhydride and diphenyl ether diamine is 0.9:1; the total amount of 4,4'-biphenyl ether dianhydride and diphenyl ether diamine accounts for 30 wt% of the reaction system. The preparation steps of the adhesive are as follows: mixing the diacid anhydride, the diamine, and the solvent, controlling the reaction temperature at 25°C, and stirring the reaction for 48 hours to obtain the adhesive.

[0078] Comparative Example 1

[0079] This comparative example provides a screen printing plate surface coating process, specifically the following steps:

[0080] S1. Wire Mesh Tension: Tensile the stainless steel wire mesh, fix it on a flat table, cut it to the required specifications, apply glue to the mesh frame, and fix the mesh fabric to the mesh frame;

[0081] S2. Removing steel wires: Place the stretched screen flat on the laser equipment and use the laser equipment to locally remove the steel wires on the screen;

[0082] S3. Cleaning: Apply cleaning agent to the mesh plate and perform ultrasonic cleaning to remove oil;

[0083] S4. Applying film: Apply PI film to the cleaned screen surface;

[0084] S5. Laser engraving: Place the baked stencil on the laser engraving equipment with the PI film facing up and align it for laser engraving.

[0085] S6. Screen Inspection: Inspect the laser-engraved screen, including appearance, graphic requirements, tension, and total thickness.

[0086] S7. Packaging: Pack the qualified screen printing plates.

[0087] The cleaning agent and PI film mentioned are commercially available products.

[0088] An enlarged view of the screen print obtained in this example is shown below. Figure 2 As shown.

[0089] Comparative Example 2

[0090] The specific implementation method of this comparative example is the same as that of Example 1, except that the diacid anhydride in the raw materials for preparing the adhesive is pyromellitic dianhydride and the diamine is p-phenylenediamine.

[0091] Comparative Example 3

[0092] The specific implementation method of this comparative example is the same as that of Example 1, except that the baking temperature in the baking step is 60°C.

[0093] Performance testing

[0094] Printability test

[0095] Test subjects: Screens obtained from Examples 1-3 and Comparative Examples 1-3 after the process described.

[0096] Test method: The actual printing counts of downstream screen printing manufacturers were statistically analyzed. Detailed test data for different wire diameter screens are shown in Tables 1 and 2.

[0097] Table 1. Application to 9μm wire diameter screen printing plates

[0098]

[0099]

[0100] Table 2. Application to 8μm wire diameter screen printing plates

[0101] Printing times Example 1 150,000 per time Example 2 180,000 / time Example 3 200,000 per time Comparative Example 1 50,000 / time Comparative Example 2 100,000 per time Comparative Example 3 120,000 per time

Claims

1. A screen printing plate surface coating process, characterized in that, At least the following steps are included: S1. Wire Mesh Tension: Tensile the stainless steel wire mesh, fix it on a flat table, cut it to the required specifications, apply glue to the mesh frame, and fix the mesh fabric to the mesh frame; S2. Removing steel wires: Place the stretched screen flat on the laser equipment and use the laser equipment to locally remove the steel wires on the screen; S3. Cleaning: Apply cleaning agent to the mesh plate and perform ultrasonic cleaning to remove oil; S4. Applying film: Apply PI film to the cleaned screen surface; S5. Spraying adhesive: Place the screen with the PI film attached under the nano spraying equipment and spray adhesive evenly; S6. Baking: Place the screen with the sprayed adhesive onto the baking mold to form a coating with the PI film; S7. Laser engraving: Place the baked stencil on the laser engraving equipment with the PI film facing up and align it for laser engraving. S8. Screen Inspection: Inspect the laser-engraved screen, including appearance, graphic requirements, tension, and total thickness. S9. Packaging: Package the qualified screen printing plates; The raw materials for preparing the adhesive include diacid anhydride, diamine and solvent, and the molar ratio of diacid anhydride to diamine is (0.85-1):(0.99-1). The aforementioned dicarboxylic acid anhydride is a dicarboxylic acid anhydride containing a benzene ring, including one or more of pyromellitic dianhydride, 3,3',4,4'-diphenyl ether dianhydride, and 4,4'-biphenyl ether dianhydride; The diamine is a diamine containing a benzene ring, including one or more of diphenyl ether diamine, p-phenylenediamine, and 4,4'-biphenylenediamine; The preparation steps of the adhesive are as follows: mixing diacid anhydride, diamine and solvent, controlling the reaction temperature at 10-25℃, and stirring the reaction for 24-48 hours to obtain the adhesive.

2. The screen printing plate surface spraying treatment process according to claim 1, characterized in that, In the baking step, the baking temperature is 100~200℃ and the baking time is 30~60min.

3. The screen printing plate surface spraying treatment process according to claim 1, characterized in that, The total amount of the dicarboxylic acid anhydride and diamine is 10-45% of the total mass of the reaction system.

Images