Polyimide functional film capable of improving wear resistance and preparation process

Abstract

The invention belongs to the technical field of photovoltaic silk-screen printing plate preparation, and particularly relates to a polyimide functional film capable of improving wear resistance and a preparation technology, the polyimide functional film comprises a finished product film body, the finished product film body is specifically composed of a wear-resistant layer, a polyimide film layer, high-temperature hot-pressing glue and a release layer; the wear-resistant layer can be coated through micro-concave roller coating equipment, and AF acrylic UV light-cured resin is selected as a coating material of the wear-resistant layer. Magnetron sputtering or evaporation can also be selected, and a sputtering or evaporation material contains all metal elements and oxides thereof in the periodic table of elements. Compared with an existing traditional polyimide film, the surface of the wear-resistant polyimide film is coated with the wear-resistant UV material or the wear-resistant metal material, the wear-resistant layer can effectively improve the wear resistance of the polyimide film, the printing life of a screen printing plate can be effectively prolonged, meanwhile, the polyimide film is prevented from being worn by a silicon wafer in the printing process, and the service life of the screen printing plate is prolonged. Especially, the abrasion near the cutting position of the edge of the silicon wafer is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic silk-screen printing plate preparation, in particular to a polyimide functional film capable of improving wear resistance and a preparation process thereof. Background Art

[0002] The current photovoltaic screen uses a woven metal mesh. The printed graphics are produced by hot-pressing a polyimide functional film on the metal mesh and then laser cutting the polyimide film. This type of screen is collectively called a polyimide screen, and is also the mainstream product of most current photovoltaic screen manufacturers. However, there is a problem with this type of screen: after hundreds of thousands of printings, the polyimide film frequently contacts the silicon wafer, causing friction between them. When the polyimide wears to a certain extent, the strength decreases, especially at the edge where the polyimide film contacts the silicon wafer. The screen is easily broken by the force of the printing scraper, thus affecting its service life. The traditional screen in the photovoltaic screen industry is still the metal screen + hot-pressed polyimide film process. Its process is relatively mature. However, due to the serious internal competition in photovoltaic cell factories in recent years, many have even suffered losses, so screen manufacturers are frequently required to improve. Regarding the printing life of polyimide screens, some battery cell manufacturers have increased the minimum printing life of the screens to 60W, otherwise they will need to pay for the life. One approach is to use steel screens and print graphics directly on the steel plates. The wear resistance of metal steel plates is definitely higher than that of organic polyimide films. Another approach is to upgrade traditional polyimide screens and coat the polyimide film surface with magnetron sputtering, evaporation, etc., or with AF acrylic UV resin by micro-concave roller coating. The coating or coating materials include metals, metal alloys, metal oxides, metal salts, silica, silicones, fluorides such as polytetrafluoroethylene, AF acrylic light-curing resins, etc.

[0003] This led to the idea of ​​a plating or coating method to improve the wear resistance of the polyimide film surface to increase its printing life.

[0004] The existing technology has the following defects or problems:

[0005] Long-term contact of polyimide film printing with silicon wafers causes wear of the polyimide film, which can easily cause the screen to break, thus affecting its service life and hindering cost reduction for customers.

[0006] It should be noted that the above content falls within the technical knowledge of the inventor and does not necessarily constitute prior art. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention provides a polyimide functional film and a preparation process that can improve wear resistance, thereby solving the existing problems.

[0008] To achieve the above object, the present invention provides the following technical solution: a polyimide functional film capable of improving wear resistance, comprising a finished film body, wherein the finished film body is specifically composed of a wear-resistant layer, a polyimide film layer, a high-temperature hot pressing adhesive, and a release layer;

[0009] The wear-resistant layer is formed by the following steps:

[0010] It is carried out by micro-concave roller coating equipment, and the coating material is AF acrylic UV light curing resin;

[0011] Magnetron sputtering wear-resistant metal or vapor deposition wear-resistant metal, the sputtering or vapor deposition material contains all metal elements and their oxides in the periodic table.

[0012] In some embodiments, the thickness of the finished film needs to be controlled between 1um and 150um, and the thickness of the wear-resistant coating needs to be controlled between 0.01um and 20um.

[0013] In some embodiments, the release layer can be selected from one of release paper, release film, CPP protective film and PE protective film.

[0014] Another technical problem to be solved by the present invention is to provide a micro-concave roller coating technology, which is one of the preparation processes for polyimide functional films that can improve wear resistance, comprising the following steps:

[0015] Step 1: Prepare 5um polyimide original film, 120um release layer and 125um PET silicone support protective film in advance;

[0016] Step 2: Pre-dilute the high-temperature hot pressing adhesive and AF acrylic light-curing resin;

[0017] Step 3: Pour AF acrylic light-curing resin into the glue tank, turn on the liquid supply pump, and allow the glue to circulate and defoam between the glue tank and the micro-concave coating tank;

[0018] Step 4: Place the polyimide original film on the unwinding rack built into the micro-concave roller coating equipment, start coating the polyimide original film, start the micro-concave roller coating equipment drive unit, and transfer the glue to the polyimide original film through the micro-concave roller to coat the AF acrylic light-curing resin;

[0019] Step 5: Then, the AF acrylic light-curing resin is dried and cured by UV lamp. This process needs to be carried out under nitrogen protection to improve the wear resistance of the cured surface.

[0020] Step 6: Place the polyimide film coated with AF acrylic light-curing resin on the unwinding rack and apply high-temperature hot-pressing adhesive on the other side. First, clean the material tank, then pour the diluted high-temperature hot-pressing adhesive into the material tank, start the equipment and turn on the speed, and transfer the glue to the other side of the polyimide film through the micro-grooves. The UV lamp is not turned on in the above process. After the film is dried in the oven, it is passed to the laminating position through the pressing roller to complete the lamination of the release layer, and finally the film is wound up.

[0021] Step 7: Cut the processed roll into 250mm width, and then slice it according to the specification of 250mm*260mm to finally obtain the finished film;

[0022] Step 8: Cut the finished film into suitable sizes to match screens of different specifications. Then tear the finished film from the release layer and stick it to the steel wire mesh. Then use a hot press to heat press it. The hot pressing parameters are 185℃*1980S. After the hot pressing is completed, the wear-resistant polyimide film screen is obtained.

[0023] Furthermore, the solid content of the high-temperature hot pressing adhesive is controlled at 23-27%, and the solid content of the AF acrylic light-curing resin is controlled at 21-25%.

[0024] Furthermore, the mesh number of the micro-concave roller for coating the AF resin is 220 mesh, the coating speed needs to be controlled at 10 m / min, and the micro-concave roller speed ratio is 1.0, and the coating thickness is controlled between 0.6-1.0 um.

[0025] Furthermore, the drying process is carried out in an oven, three groups of UV lamps are provided, and the energy of each group of UV lamps is set at 60%. After the UV curing, the water contact angle of the surface of the AF acrylic light-curing resin must be greater than 105 degrees.

[0026] Furthermore, the mesh number of the micro-concave roller for applying the high-temperature glue is 110 meshes, the coating speed needs to be controlled to 8 m / min, and the micro-concave roller speed ratio is 1.0.

[0027] Compared with the prior art, the present invention provides a polyimide functional film and a preparation process that can improve wear resistance, which has the following beneficial effects:

[0028] Compared with the existing traditional polyimide film, the present invention has a polyimide functional film and preparation process that can improve wear resistance. The surface of the polyimide film is coated or plated with a wear-resistant layer. This layer of material can effectively improve the wear resistance of the polyimide film and the printing life of the screen. At the same time, it prevents the polyimide film from being worn by the silicon wafer during use, especially the wear near the cutting position of the silicon wafer edge. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the composition structure of the polyimide functional membrane of the present invention;

[0030] Figure 2 This is a spectrum diagram of sputtering deposition example 1 of embodiment 2 of the polyimide functional film of the present invention;

[0031] Figure 3 This is a second spectrum of sputtering deposition example 2 of the polyimide functional film embodiment 2 of the present invention;

[0032] Figure 4 This is the third spectrum of the sputtering deposition example of the second embodiment of the polyimide functional film of the present invention.

[0033] In the figure: 1. Finished film body; 11. Wear-resistant layer; 12. Polyimide film layer; 13. High-temperature hot pressing adhesive; 14. Release layer. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] It should be understood that the step numbers used herein are only for convenience of description and are not intended to limit the order in which the steps are executed.

[0036] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0037] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0038] The term "and / or" refers to and includes any and all possible combinations of one or more of the associated listed items.

[0039] See also Figure 1

[0040] Example 1: A polyimide functional film capable of improving wear resistance includes a finished film body 1, wherein the finished film body 1 is specifically composed of a wear-resistant layer 11, a polyimide film layer 12, a high-temperature hot pressing adhesive 13, and a release layer 14;

[0041] The steps for implementing the wear-resistant layer are as follows: using a micro-concave roller coating device, the coating material is AF acrylic UV light curing resin;

[0042] The thickness of the finished film 1 needs to be controlled between 1um-150um, and the thickness of the wear-resistant coating 11 needs to be controlled between 0.01um-20um;

[0043] The release layer 14 can be made of one of release paper, release film, CPP protective film and PE protective film;

[0044] Based on the above-mentioned polyimide functional film capable of improving wear resistance, a preparation process of the polyimide functional film capable of improving wear resistance is proposed, and the specific steps are as follows:

[0045] Step 1: Prepare 5um polyimide original film, 120um release layer 14 and 125um PET silicone support protective film in advance;

[0046] Step 2: Pre-dilute the high-temperature hot pressing adhesive 13 and the AF acrylic light-curing resin;

[0047] The solid content of high temperature hot pressing adhesive 13 is controlled at 23-27%, and the solid content of AF acrylic light curing resin is controlled at 21-25%;

[0048] Step 3: Pour AF acrylic light-curing resin into the glue tank, turn on the liquid supply pump, and allow the glue to circulate and defoam between the glue tank and the micro-concave coating tank;

[0049] Step 4: Place the polyimide original film on the unwinding rack built into the micro-concave roller coating equipment, start coating the polyimide original film, start the micro-concave roller coating equipment drive unit, transfer glue to the polyimide original film through the micro-concave roller, and coat the AF acrylic light-curing resin;

[0050] The mesh number of the micro-concave roller is 220 mesh, the coating speed needs to be controlled at 10m / min, and the micro-concave roller speed ratio is 1.0, and the coating thickness is controlled between 0.6-1.0um;

[0051] Step 5: Then, the AF acrylic light-curing resin is dried and cured by UV lamp. This process needs to be carried out under nitrogen protection to improve the wear resistance of the cured surface.

[0052] The drying process is carried out in an oven. Three groups of UV lamps are set, and their energy is set at 60%. After UV curing, the water contact angle on the surface of the AF acrylic light-curing resin must be greater than 105 degrees.

[0053] Step 6: Place the polyimide original film coated with AF acrylic light-curing resin on the unwinding rack and apply high-temperature hot-pressing adhesive 13 on the other side. First, clean the material tank, then pour the diluted high-temperature hot-pressing adhesive 13 into the material tank, start the equipment and turn on the speed, transfer the glue to the other side of the polyimide original film through the micro-grooves. In the above process, the UV lamp is not turned on. After the film is dried in the oven, it is passed to the laminating position through the pressing roller to complete the lamination of the release layer 14, and finally the film is wound up.

[0054] The mesh number of the micro-concave roller is 110 mesh, the coating speed needs to be controlled at 8m / min, and the micro-concave roller speed ratio is 1.0;

[0055] Step 7: Cut the processed roll into 250mm width, and then slice it according to the specification of 250mm*260mm to finally obtain the finished film body 1;

[0056] Step 8: The finished film body 1 is now cut into suitable sizes to match screens of different specifications. The finished film body 1 is then torn off the release layer 14 and bonded to the steel wire mesh. The finished film body 1 is then hot-pressed using a hot press at a temperature of 185°C for 1980 seconds. After the hot pressing is completed, a wear-resistant polyimide film screen is obtained.

[0057] See also Figure 1-4

[0058] Embodiment 2: comprising a finished film body 1, the finished film body 1 is specifically composed of a wear-resistant coating 11, a polyimide film layer 12, a high-temperature hot pressing adhesive 13 and a release layer 14;

[0059] The wear-resistant layer is formed by magnetron sputtering or evaporation, wherein the sputtering or evaporation material contains all metal elements and their oxides in the periodic table.

[0060] The release layer 14 can be made of one of release paper, release film, CPP protective film and PE protective film.

[0061] Based on the above-mentioned polyimide functional film capable of improving wear resistance, a preparation process of the polyimide functional film capable of improving wear resistance is proposed, and the specific steps are as follows:

[0062] Step 1: Prepare 5um polyimide original film, 120um release layer 14 and 125um PET silicone support protective film in advance;

[0063] Step 2: Use magnetron sputtering to deposit nickel target metal on a 5um polyimide film. Fill an appropriate amount of argon gas under high vacuum conditions, apply a DC voltage between the cathode cylindrical target or flat target and the anode coating chamber wall, and generate a magnetron abnormal glow discharge in the coating chamber. Under the action of the electric field, the electrons enable the neutral atoms or molecules on the target surface to obtain sufficient kinetic energy to break away from the target surface and deposit on the substrate surface to form a thin film. Finally, a nickel-plated metal PI functional film is obtained, and the coating thickness is controlled between 0.4-0.6um.

[0064] Step 3: Apply the high-temperature hot-press adhesive to the other side of the 5umPI film using a precise micro-concave roller coating technique. After drying the solvent in the adhesive, the adhesive is then laminated with the release material using the laminating roller of the coating machine. The solid content of the high-temperature hot-press adhesive 13 is controlled at 23-27%, and the finished product is finally obtained.

[0065] Step 4: Cut the finished film 1 into suitable sizes to match screens of different specifications, then peel off the finished film 1 from the release layer 14 and attach it to the steel wire mesh cloth, and heat press it with a hot press at a temperature of 185°C for 1980 seconds. After the hot press is completed, a wear-resistant polyimide film screen is obtained.

[0066] In the above-mentioned sputtering deposition example 1, the content of the plating metal components, the main components of which are chromium and tungsten, are as follows:

[0067] Metal elements Wt% Wt%Sigma C 59.73 0.25 N 5.92 0.32 O 18.79 0.16 Si 0.41 0.02 Cr 13.56 0.11 W 1.59 0.07 Total 100

[0068] In the above-mentioned sputtering deposition example 2, the content of the metal plating components, the main components of which are chromium, nickel and copper, are as follows:

[0069] Metal elements Wt% Wt%Sigma C 60.16 0.28 N 6.32 0.32 O 17.97 0.15 Si 0.17 0.02 Cr 1.17 0.05 Ni 10.65 0.15 Cu 3.56 0.13 Total 100

[0070] In the above-mentioned sputtering deposition example 3, the content of the plating metal components, the main components of which are chromium, nickel and copper, are as follows:

[0071] Metal elements Wt% Wt% Sigma C 65.36 0.28 N 5.78 0.32 O 19.67 0.15 Cr 0.67 0.04 Ni 6.31 0.12 Cu 2.21 0.11 Total 100

[0072] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiments are described briefly because they are generally similar to the method embodiments. For relevant parts, refer to the description of the method embodiments.

[0073] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A polyimide functional film capable of improving wear resistance, characterized by: The finished film body (1) is composed of a wear-resistant layer (11), a polyimide film layer (12), a high-temperature hot pressing adhesive (13) and a release layer (14); The wear-resistant layer (11) is implemented in a first embodiment by a micro-concave roller coating device, wherein the coating material is AF acrylic UV light-curing resin. The wear-resistant layer (11) is implemented in a second embodiment by magnetron sputtering or evaporation, wherein the sputtering or evaporation material includes all metal elements and their oxides in the periodic table.

2. The polyimide functional film capable of improving wear resistance according to claim 1, wherein: The thickness of the finished film (1) needs to be controlled between 1um and 150um, and the thickness of the wear-resistant layer (11) needs to be controlled between 0.01um and 20um.

3. The polyimide functional film capable of improving wear resistance according to claim 1, wherein: The release layer (14) can be made of one of release paper, release film, CPP protective film and PE protective film.

4. One of the preparation processes for polyimide functional films that can improve wear resistance is a micro-concave roller coating method, characterized in that: The steps include: Step 1: Prepare in advance a 5um polyimide original film, a 120um release layer (14), and a 125um PET silicone support protective film; Step 2: pre-dilute the high temperature hot pressing adhesive (13) and AF acrylic light curing resin; Step 3: Pour AF acrylic light-curing resin into the glue tank, turn on the liquid supply pump, and allow the glue to circulate and defoam between the glue tank and the micro-concave coating tank; Step 4: Place the polyimide original film on the unwinding rack built into the micro-concave roller coating equipment, start winding the polyimide original film, start the micro-concave roller coating equipment drive unit, transfer glue to the polyimide original film through the micro-concave roller, and simultaneously coat the AF acrylic light-curing resin; Step 5: Then, the AF acrylic light-curing resin is dried and cured by UV lamp. This process needs to be carried out under nitrogen protection to improve the wear resistance of the cured surface. Step 6: Place the polyimide original film coated with AF acrylic light-curing resin on the unwinding rack and apply high-temperature hot-pressing adhesive (13) on the other side. First, clean the material tank, then pour the diluted high-temperature hot-pressing adhesive (13) into the material tank, start the equipment and turn on the speed, transfer the glue to the other side of the polyimide original film through the micro-grooves. In the above process, the UV lamp is not turned on. After the film is dried in the oven, it is passed to the laminating position through the pressing roller to complete the lamination of the release layer (14), and finally the winding is completed; Step 7: Cut the processed roll into 250mm width, and then slice it according to the specification of 250mm*260mm to finally obtain the finished film body (1); Step 8: The finished film body (1) is cut into suitable sizes to match screens of different specifications. The release layer (14) of the finished film body (1) is then torn off, and the side coated with high-temperature hot pressing adhesive is attached to the steel wire metal mesh. The film is then hot-pressed using a hot press, wherein the hot pressing parameters are 185°C*1980S. After the hot pressing is completed, a wear-resistant polyimide film screen is obtained.

5. The process for preparing a polyimide functional film capable of improving wear resistance according to claim 1, wherein: In step 2, the solid content of the high temperature hot pressing adhesive (13) is controlled at 23-27%, and the solid content of the AF acrylic light curing resin is controlled at 21-25%.

6. The process for preparing a polyimide functional film capable of improving wear resistance according to claim 1, wherein: In step 4, the mesh number of the micro-concave roller is 220 mesh, the coating speed needs to be controlled at 10 m / min, and the micro-concave roller speed ratio is 1.0, and the coating thickness is controlled between 0.6-1.0 μm.

7. The process for preparing a polyimide functional film capable of improving wear resistance according to claim 1, wherein: The drying treatment in step 5 is carried out in an oven. Three groups of UV lamps are provided, and the energy of each group of UV lamps is set at 60%. The water contact angle of the surface of the AF acrylic light-curing resin after UV curing must be greater than 105 degrees.

8. The process for preparing a polyimide functional film capable of improving wear resistance according to claim 1, wherein: The mesh number of the micro-concave roller in step 6 is 110 mesh, the coating speed needs to be controlled at 8 m / min, and the micro-concave roller speed ratio is 1.0.

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