A film pasting process for free-form surface pasting

Abstract

The present application relates to a kind of for free curved surface pasting film process and device, pasting film process includes in two steps of glue layer pretreatment and sample pasting film, glue is with PMHS and vinyl trimethylsilane, octene, hexene etc. as raw material, glue layer processing includes the steps such as defoaming treatment, initial solidification, overflow glue removal and post-curing, software operation step is completed with a kind of pasting film device for free curved surface pasting film, and pasting film is more firm by preposition printing glue layer processing, subsequent pasting film device and software cooperation can realize the pasting film of arbitrary curved surface to industrial material, it is relatively simple to operate, and not only can be effective in plane pasting film, also can be free curved surface vacuum pasting film to three-dimensional solid stronger article.

Description

Technical Field

[0001] This invention relates to the field of electronic device screen technology, and more specifically to a film bonding process for bonding free-form surfaces. Background Technology

[0002] With the booming development of the high-tech electronics and information industry, consumer electronics products have become necessities in people's daily lives, and many consumer electronics products are moving towards a trend of being thinner and smaller. In particular, touch display panels that combine display and input technologies have both liquid crystal display and touch input functions, which can greatly improve the practical performance of various consumer electronics products, making the installation of screen protectors very necessary.

[0003] UV adhesive is a special type of glue that requires ultraviolet light to cure. This means that a specialized UV lamp or device is needed to irradiate the adhesive for rapid curing. UV adhesive requires no waiting time; it cures within seconds of UV exposure, saving significant time. It also boasts high transparency, allowing application to transparent or translucent materials without affecting their appearance. Therefore, UV adhesive is very popular in electronics, glass processing, and jewelry making, but further improvements are still needed.

[0004] Industrial films are made of PET substrate and utilize advanced multilayer metal sputtering, vacuum and ion technologies, as well as thin film physics and fine chemical technologies, giving them extremely high heat insulation efficiency, high tensile strength, high elongation, and strong acid and alkali resistance.

[0005] Existing devices for applying films to industrial materials typically include a flat roller and a cutting blade. The flat roller presses the film onto the industrial material and the cutting blade cuts the film off, thus completing the film application.

[0006] However, flat rollers can only apply films to flat surfaces of industrial materials and are not suitable for applying films to curved surfaces, thus limiting their application. Summary of the Invention

[0007] The technical objective of this invention is to solve the problems in the background art and provide a film bonding process for bonding free-form surfaces.

[0008] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A film bonding process for bonding free-form surfaces, comprising the following steps: Step (1) Print adhesive on the surface of the release film to form an adhesive layer; Step (2) Let the sample stand to allow the air bubbles on the adhesive layer to burst automatically; Step (3) Degas the adhesive layer, perform initial curing, and remove excess adhesive; Curing after step (4); Step (5) Apply a film to the sample; Preferably, step (5) involves applying a film to the sample using a specially designed film-applying device for bonding free-form surfaces, which is operated in conjunction with computer operation.

[0009] Preferably, the adhesive in step (1) is prepared using a photoinitiator, an adhesion promoter (PMHS polymethylsiloxane), vinyltrimethylsilane, octene, hexene, and toluene; wherein the photoinitiator is one or a combination of several of 2,2-dimethoxy-1,2-diphenylethyl-1-one, trimethylbenzoyldiphenylphosphine oxide, 1-hydroxycyclohexylbenzophenone, and 2-methyl-1-(4-methylthiophenyl)-2-dimethylthiopropyl-1-one; the adhesion promoter is PMHS polymethylsiloxane, the photoinitiator is 1-10 parts by mass, and the adhesion promoter is 5-15 parts by mass. The preparation steps are as follows: S11 is uniformly mixed with vinyltrimethoxysilane and hexene in a molar ratio between 0.1 and 1 to obtain mixture A; S12 is a mixture of vinyltrimethoxysilane and octene in a molar ratio of 0.1-0.5 and vinyltrimethoxysilane and octene in a molar ratio of 1:2 to obtain mixture B; S13. The above mixture A and mixture B are added to a toluene solution of trimethylsiloxy-terminated polymethylhydrosiloxane PMHS, wherein the mass fraction of the toluene solution is between 0.1% and 5%, and the total mass fraction of A and B is between 50 and 85 parts. S14 involves continuously stirring the mixture and heating it to 50-90°C, then heating and stirring the reaction mixture under reflux until complete Si-H conversion is detected using FT-IR, thus obtaining the adhesive to be used.

[0010] Preferably, the thickness of the adhesive layer in step (1) is between 15 and 30 µm.

[0011] The advantages of using this invention lie in the fact that polymethylhydrosiloxane (PMHS) is one of the organosilicon modifiers, primarily due to its high chemical stability, non-toxicity, and low cost under atmospheric conditions (including high humidity). Furthermore, due to the presence of reactive Si-H groups, polyhydrosiloxanes and disiloxanes can be modified with selected functional groups during hydrosilylation reactions, thereby allowing for broad control over hydrophobicity, rheology, and dispersibility. This enables the properties of the siloxane to be matched with the polymer matrix to be compounded, resulting in materials with high homogeneity and desired properties. The realization of linear polymethylhydrosiloxane (PMHS) as a component is a key improvement in the durability and functionality of coatings. Adding PMHS to the raw materials for adhesive preparation can improve the hydrophobicity of the adhesive and enhance its adhesion stability. Controlling the adhesive layer thickness between 15-30µm can ensure stable adhesion between the film and the sample, while also preventing excessive thickness that could lead to a poor user experience when using the screen. Initial curing is the process of reaching a certain strength under specific temperature conditions over a period of time, where the surface has hardened and is no longer sticky, but curing is not yet complete. Post-curing is a treatment performed on the basically cured adhesive to improve adhesion performance or as required by the process. It is generally carried out at a certain temperature for a period of time to supplement curing, further improve the degree of curing, effectively eliminate internal stress, and improve the bond strength.

[0012] The advantage of using this invention is that adding an adhesion promoter to the coating system can effectively improve the adhesion between the coating and the metal substrate, thereby improving the overall performance of the coating.

[0013] As a preferred option, in step (2), the sample is left to stand under atmospheric pressure to allow the bubbles to burst automatically for 20-60 minutes.

[0014] As a preferred option, step (3) initial curing involves subjecting the semi-finished product and the fixing fixture to ultraviolet light to locally cure the adhesive layer, and cleaning excess adhesive involves wiping the excess adhesive on the semi-finished product with a lint-free cloth soaked in alcohol.

[0015] Preferably, the post-curing step (4) involves placing the semi-finished product and the fixing fixture in a UV exposure machine or a UV tunnel oven for full final curing.

[0016] The advantage of using this invention is that it performs a first curing and a second curing on the semi-finished product, making the adhesive more robust and improving the reliability of the product quality.

[0017] Preferably, step (5) of applying a film to the sample includes the following steps: S51 air pressure check, the air pressure gauge shows 0.5-0.7MPa, which is within the normal range; Power on the S52 device, turn on the computer power switch after turning on the power switch; S53 opens the software TP111MV; To reset the S54, press and hold the initial button until the icon changes from red to green, indicating that initialization is complete. After confirming the S55 pressure parameters and selecting the appropriate bonding pressure, the device enters production mode. S56 Press the "Production Mode" button and then press the "Start" button to enter production mode.

[0018] Preferably, the bonding pressure described in S5 is set to a commonly used value of 150.

[0019] As a preferred option, the film application process also involves platform operations, including module placement and flip-up cover placement.

[0020] As a preferred method, the module placement process is as follows: First, place the membrane using a fixture, press the left pressure head to confirm that the vacuum value has reached the set value, remove the module protection, and finally press the start button to send it to the lower platform for operation. Flip-plate placement operation: After the flip-plate is flipped into place, confirm that the flip-plate vacuum reaches the set value and the vacuum reaches the four tops, place the cover plate, tear off the OCA release film of the cover plate, and press the start button again to send the flip-plate in for vacuum bonding.

[0021] As a preferred embodiment, the special film-applying device used in step (5) for applying film to free-form surfaces includes an mounting sleeve, two sets of bolts, two sets of first connecting rods, two sets of second connecting rods, a sliding sleeve, a fixing rod, a drive device, a rotating mechanism, a telescopic device, and a film-applying device. The upper parts of the front and rear ends of the mounting sleeve are connected with threaded holes. The two sets of bolts are threadedly connected to the two sets of threaded holes of the mounting sleeve. One end of each of the two sets of first connecting rods is rotatably installed at the front and rear ends of the mounting sleeve. The other end of each of the two sets of first connecting rods is rotatably connected to the top of each of the two sets of second connecting rods. The bottom ends of each of the two sets of second connecting rods are rotatably connected to the front and rear ends of the sliding sleeve. The fixing rod is installed at the bottom of the mounting sleeve. The sliding sleeve is slidably connected to the fixing rod. The drive device is installed inside the fixing rod. The rotating mechanism is installed on the sliding sleeve. The telescopic device is installed at the bottom of the rotating mechanism. The film-applying device is installed on the telescopic device. The drive device includes a first electric push rod and a V-shaped frame. A through groove is provided in the middle of the fixed rod. The first electric push rod is installed at the top of the through groove. The V-shaped frame is installed at the output end of the first electric push rod. The V-shaped frame corresponds to the positions of the two sets of first connecting rods. A rubber pad is provided at the top of the V-shaped frame. The rotating mechanism includes two sets of connecting plates, four sets of rivets, a rotating ring, a fixed gear, multiple sets of rollers, a drive gear, and a motor. The two sets of connecting plates are installed on the left and right ends of the sliding sleeve by four sets of rivets. The fixed gear is installed on the bottom end of the two sets of connecting plates. The outer side of the fixed gear is provided with a groove. The rotating ring is slidably engaged with the outer side of the fixed gear by multiple sets of rollers. The motor is installed on the outer end of the rotating ring. The drive gear is installed on the output end of the motor. The drive gear meshes with the fixed gear. The telescopic device is installed on the rotating ring. The telescopic device includes three sets of second electric push rods, three sets of connecting blocks, three sets of third connecting rods, three sets of guide rails, and three sets of sliders. The three sets of second electric push rods are equally installed on the outer end of the rotating ring. The three sets of connecting blocks are respectively installed on the output ends of the three sets of second electric push rods. The three sets of third connecting rods are respectively installed on the three sets of connecting blocks. The three sets of guide rails are equally installed on the bottom end of the rotating ring. The three sets of sliders are respectively connected to the three sets of third connecting rods. The three sets of sliders slide on the three sets of guide rails. The film-applying device is installed at the bottom end of the three sets of sliders.

[0022] Preferably, the film-applying device includes three sets of support rods, three sets of springs, three sets of support frames, and three sets of flattening rollers. The three sets of support rods are respectively installed at the bottom of the three sets of sliders. A third electric push rod is installed between the bottom of the slider and the spring. The bottom of the three sets of support rods is provided with a telescopic groove. The three sets of support frames are slidably connected to the telescopic grooves of the three sets of support rods. The three sets of springs are respectively sleeved on the three sets of support frames. One end of the three sets of springs is connected to the three sets of support rods, and the other end of the three sets of springs is connected to the three sets of support frames. The three sets of flattening rollers are rotatably installed at the bottom of the three sets of support frames.

[0023] The advantages of this invention lie in the fact that the mounting sleeve is fitted to the film applicator, and then two sets of bolts are rotated to connect to the mounting sleeve via threads, thus installing the mounting sleeve. The drive device is then activated, causing it to move downwards. The two sets of first connecting rods, two sets of second connecting rods, and the sliding sleeve follow the drive device downwards due to gravity. Once the film applicator contacts the film, the rotating mechanism is activated, causing the film applicator to rotate. Simultaneously, the telescopic device is activated, causing the film applicator to move from the inside out, thereby applying the film to the industrial material from all angles. This device allows for film application to any curved surface of industrial materials, simplifying operation and reducing limitations. An additional third electric push rod is added between the flattening roller and the slider, enabling the flattening roller to not only perform flat film application but also to vacuum apply film to free-form surfaces of three-dimensional objects. Attached Figure Description

[0024] Figure 1 This is a first-view structural schematic diagram of the film-applying device for the film-applying process of the present invention for bonding free-form surfaces. Figure 2 This is a second-view structural schematic diagram of the film-applying device of the present invention; Figure 3 yes Figure 2 A magnified structural diagram of B in the diagram; Figure 4 yes Figure 1 A magnified structural diagram of A in the middle; The following are labels in the attached diagram: 1. Mounting sleeve; 2. Bolt; 3. First connecting rod; 4. Second connecting rod; 5. Sliding sleeve; 6. Fixing rod; 7. First electric push rod; 8. V-shaped frame; 9. Through groove; 10. Connecting plate; 11. Rivet; 12. Rotating ring; 13. Fixed gear; 14. Roller; 15. Drive gear; 16. Motor; 17. Second electric push rod; 18. Connecting block; 19. Third connecting rod; 20. Guide rail; 21. Slider; 22. Support rod; 23. Spring; 24. Support frame; 25. Flattening roller; 26. Third electric push rod. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention. Example 1

[0026] Step (1) Print adhesive on the surface of the release film to form an adhesive layer with a thickness of 25µm; The adhesive preparation process is as follows: Vinyltrimethoxysilane and hexene are uniformly mixed in a molar ratio of 1:2 to obtain mixture A; vinyltrimethoxysilane and octene are uniformly mixed in a molar ratio of 1:4 and 1:2 to obtain mixture B; mixtures A and B are added to a toluene solution of trimethylsiloxy-terminated polymethylhydrosiloxane (PMHS) and a photoinitiator, where the mass fraction of the toluene solution is 1%, the total mass fraction of A and B is 80 parts, the mass fraction of the photoinitiator is 5 parts, and the mass fraction of the adhesion promoter is 15 parts; the mixture is continuously stirred and heated to 70°C, and then the reaction mixture is heated and stirred under reflux until complete Si-H conversion is detected by FT-IR to obtain the desired adhesive.

[0027] Step (2) Let the sample stand for 30 minutes to allow the air bubbles on the adhesive layer to burst automatically; Step (3) Degas the adhesive layer, perform initial curing, and remove excess adhesive; Curing after step (4); Step (5) Apply a film to the sample.

[0028] Step (5) of the process after the platform operation includes the following steps for applying a film to the sample: S51 air pressure check, the pressure gauge shows 0.6MPa; Power on the S52 device, turn on the computer power switch after turning on the power switch; S53 opens the software TP111MV; To reset the S54, press and hold the initial button until the icon changes from red to green, indicating that initialization is complete. S55 After confirming the pressure parameters and selecting the appropriate bonding pressure, the device enters the production mode. S56 Press the "Production Mode" button and then press the "Start" button to enter production mode.

[0029] As a preferred embodiment of the present invention, step (5) of applying a film to the sample uses a film-applying device for bonding free-form surfaces, such as... Figures 1 to 4 As shown, the present invention provides a film-applying device for bonding free-form surfaces, comprising a mounting sleeve 1, two sets of bolts 2, two sets of first connecting rods 3, two sets of second connecting rods 4, a sliding sleeve 5, a fixing rod 6, a driving device, a rotating mechanism, a telescopic device, and a film-applying device. The upper parts of the front and rear ends of the mounting sleeve 1 are both provided with threaded holes. The two sets of bolts 2 are threadedly connected to the two sets of threaded holes of the mounting sleeve 1. One end of each of the two sets of first connecting rods 3 is rotatably mounted on the front and rear ends of the mounting sleeve 1, and the other end of each set of first connecting rods 3 is rotatably connected to the top ends of the two sets of second connecting rods 4. The bottom ends of each set of second connecting rods 4 are rotatably connected to the front and rear ends of the sliding sleeve 5. The fixing rod 6 is mounted on the bottom end of the mounting sleeve 1, and the sliding sleeve 5 is slidably connected to the fixing rod 6. The driving device is mounted inside the fixing rod 6, the rotating mechanism is mounted on the sliding sleeve 5, the telescopic device is mounted at the bottom of the rotating mechanism, and the film-applying device is mounted on the telescopic device. Mounting sleeve 1 is assembled with the film applicator. Then, by rotating two sets of bolts 2, the two sets of bolts 2 are threadedly connected to mounting sleeve 1, thus installing mounting sleeve 1. Then, the drive device is turned on, and the drive device moves downward. The two sets of first connecting rods 3, the two sets of second connecting rods 4, and the sliding sleeve 5 follow the drive device downward due to gravity. When the film applicator contacts the film, the rotating mechanism is turned on, which drives the film applicator to rotate. At the same time, the telescopic device is turned on, which drives the film applicator to move from the inside to the outside, thereby applying the film to the industrial material from all directions. By setting up this equipment, film can be applied to any curved surface of industrial materials. The operation is relatively simple, reducing its limitations.

[0030] As a preferred embodiment of the above, the driving device includes a first electric push rod 7 and a V-shaped frame 8. A through groove 9 is provided in the middle of the fixed rod 6. The first electric push rod 7 is installed at the top of the through groove 9. The V-shaped frame 8 is installed at the output end of the first electric push rod 7. The V-shaped frame 8 corresponds to the positions of the two sets of first connecting rods 3. By setting up the first electric push rod 7, the V-shaped frame 8 and the through groove 9, by opening the first electric push rod 7, the first electric push rod 7 drives the V-shaped frame 8 to move downward. The two sets of first connecting rods 3, which do not receive the support of the V-shaped frame 8, move downward with the V-shaped frame 8, thus driving the overall movement of the sliding sleeve 5.

[0031] As a preferred embodiment of the above, the rotating mechanism includes two sets of connecting plates 10, four sets of rivets 11, a rotating ring 12, a fixed gear 13, multiple sets of rollers 14, a drive gear 15, and a motor 16. The two sets of connecting plates 10 are installed on the left and right ends of the sliding sleeve 5 by the four sets of rivets 11. The fixed gear 13 is installed on the bottom end of the two sets of connecting plates 10. A groove is provided on the outer side of the fixed gear 13. The rotating ring 12 is slidably engaged with the annular groove on the outer side of the fixed gear 13 by the multiple sets of rollers 14. The motor 16 is installed on the outer end of the rotating ring 12. The drive gear 15 is installed on the output end of the motor 16. The drive gear 15 meshes with the fixed gear 13. The telescopic device is installed on the rotating ring 12. By setting up a connecting plate 10, rivets 11, a rotating ring 12, a fixed gear 13, rollers 14, a drive gear 15, and a motor 16, when the motor 16 is turned on, the motor 16 drives the drive gear 15 to rotate. The drive gear 15 meshes with the fixed gear 13. The drive gear 15 drives the rotating ring 12 to rotate around the fixed gear 13 through multiple sets of rollers 14. The rotating ring 12 drives the film-applying device on the telescopic device to rotate, thus playing the role of driving the film-applying device to rotate.

[0032] As a preferred embodiment of the above, the telescopic device includes three sets of second electric push rods 17, three sets of connecting blocks 18, three sets of third connecting rods 19, three sets of guide rails 20, and three sets of sliders 21. The three sets of second electric push rods 17 are equally installed on the outer end of the rotating ring 12. The three sets of connecting blocks 18 are respectively installed on the output end of the three sets of second electric push rods 17. The three sets of third connecting rods 19 are respectively installed on the three sets of connecting blocks 18. The three sets of guide rails 20 are equally installed on the bottom end of the rotating ring 12. The three sets of sliders 21 are respectively connected to the three sets of third connecting rods 19. The three sets of sliders 21 slide on the three sets of guide rails 20. The film application device is installed on the bottom end of the three sets of sliders 21. By setting up a second electric push rod 17, a connecting block 18, a third connecting rod 19, a guide rail 20, and a slider 21, by opening the three sets of second electric push rods 17, the three sets of second electric push rods 17 drive the three sets of sliders 21 to slide from the inside to the outside on the three sets of guide rails 20 through the three sets of connecting blocks 18 and the three sets of third connecting rods 19. The three sets of sliders 21 then drive the film-applying device to slide outward, thereby enabling the rotating film-applying device to apply the film to the industrial material from all directions, thus achieving the function of applying the film to the industrial material from all directions.

[0033] As a preferred embodiment of the above, the film-applying device includes three sets of support rods 22, three sets of springs 23, three sets of support frames 24, and three sets of flattening rollers 25. The three sets of support rods 22 are respectively installed at the bottom of the three sets of sliders 21. A third electric push rod 26 is installed between the bottom of the slider 21 and the spring 23. The bottom of the three sets of support rods 22 is provided with a telescopic groove. The three sets of support frames 24 are slidably connected to the telescopic grooves of the three sets of support rods 22. The three sets of springs 23 are respectively sleeved on the three sets of support frames 24. One end of the three sets of springs 23 is connected to the three sets of support rods 22, and the other end of the three sets of springs 23 is connected to the three sets of support frames 24. The three sets of flattening rollers 25 are rotatably installed at the bottom of the three sets of support frames 24. By setting up support rods 22, springs 23, support frames 24 and flattening rollers 25, the three sets of flattening rollers 25, under the action of the three sets of springs 23, will apply the film to any curved surface of the industrial material, thus playing the role of applying the film to any curved surface of the industrial material.

[0034] As a preferred embodiment of the above, a rubber pad is provided at the top of the V-shaped frame 8, which can protect the V-shaped frame 8 and the first connecting rod 3.

[0035] A film-applying device for bonding free-form surfaces, in operation, firstly, the mounting sleeve 1 is fitted onto the film-applying machine. Then, by rotating two sets of bolts 2, which are threadedly connected to the mounting sleeve 1, the mounting sleeve 1 is installed. Next, the first electric push rod 7 is activated, causing the V-shaped frame 8 to move downwards. Without the support of the V-shaped frame 8, the two sets of first connecting rods 3, two sets of second connecting rods 4, and the sliding sleeve 5 move downwards under gravity along with the drive device. When the three sets of flattening rollers 25 contact the film, the motor 16 is activated, driving the drive gear 15 to rotate. The drive gear 15 meshes with the fixed gear 13, driving the rotating ring... 12 rotates around a fixed gear 13 via multiple sets of rollers 14. The rotating ring 12 drives three sets of flattening rollers 25 to rotate, and simultaneously opens three sets of second electric push rods 17. The three sets of second electric push rods 17 drive three sets of sliders 21 to slide from the inside to the outside on three sets of guide rails 20 via three sets of connecting blocks 18 and three sets of third connecting rods 19. The three sets of sliders 21 drive the three sets of flattening rollers 25 to slide outward. The three sets of flattening rollers 25, under the action of three sets of springs 23, can apply the film to any curved surface of industrial materials. An additional third electric push rod is added between the flattening rollers and the sliders, so that the flattening rollers can not only be effective in flat film application, but also perform free-form vacuum film application on three-dimensional objects. Example 2

[0036] Similar to Example 1, except that in the preparation of the adhesive layer, vinyltrimethoxysilane and hexene in a molar ratio of 1:1 are uniformly mixed to obtain mixture A; vinyltrimethoxysilane and octene in a molar ratio of 1:4 and vinyltrimethoxysilane and octene in a molar ratio of 1:1 are uniformly mixed to obtain mixture B; mixture A and mixture B are added to a toluene solution of trimethylsiloxy-terminated polymethylhydrosiloxane (PMHS) and photoinitiator, with a toluene solution mass fraction of 1%, a total mass fraction of A and B of 85 parts, a mass fraction of photoinitiator of 10 parts, and a mass fraction of adhesion promoter of 5 parts; the mixture is continuously stirred and heated to 70°C, and then the reaction mixture is heated and stirred in reflux until complete Si-H conversion is detected by FT-IR to obtain the desired adhesive. Example 3

[0037] Similar to Example 1, except that in the preparation of the adhesive layer, vinyltrimethoxysilane and hexene are uniformly mixed in a molar ratio of 1:10 to obtain mixture A; vinyltrimethoxysilane and octene are uniformly mixed in a molar ratio of 1:2 and vinyltrimethoxysilane and octene in a molar ratio of 1:10 to obtain mixture B; mixture A and mixture B are added to a toluene solution of trimethylsiloxy-terminated polymethylhydrosiloxane (PMHS) and photoinitiator, with a toluene solution mass fraction of 1%, a total mass fraction of A and B of 75 parts, a mass fraction of photoinitiator of 10 parts, and a mass fraction of adhesion promoter of 15 parts; the mixture is continuously stirred and heated to 70°C, and then the reaction mixture is heated and stirred in reflux until complete Si-H conversion is detected by FT-IR to obtain the desired adhesive. Comparative Example 1

[0038] Step (1) Print adhesive on the surface of the release film to form an adhesive layer with a thickness of 25µm; The glue is a common UV glue available on the market today.

[0039] Step (2) Let the sample stand for 30 minutes to allow the air bubbles on the adhesive layer to burst automatically.

[0040] Step (3) Degassing and initial curing of the adhesive layer, and removal of excess adhesive.

[0041] Curing after step (4).

[0042] Step (5) Apply a film to the sample.

[0043] Step (5) of the process after the platform operation includes the following steps for applying a film to the sample: S1 air pressure check, the pressure gauge shows 0.6MPa; Power on the S2 device, turn on the computer power after the power switch is turned on; S3 opens the software TP111MV; To reset the S4, long press the initial button until the icon changes from red to green, indicating that initialization is complete. S5 Confirm the pressure parameters, select the appropriate bonding pressure, and then the device enters the production mode. S6 Press the "Production Mode" button and then press the "Start" button to enter production mode.

[0044] Peel tests were conducted on Example 1 and Comparative Example 1 under the same environment, using different adhesives and instruments. The one that peeled first had lower peel strength. The results of the embodiments of the present invention were compared using the following test methods and standards.

[0045] 1. Peelability test

[0046] Apply glue evenly to one end of a patterned metal template, cover it with an optical PC film, and use a pressure roller to press it from the glued end to the other end. Then, irradiate it under an 800mw / cm×cm glue lamp for 2 seconds and peel off the PC film. The glue is distributed on the PC film and separates from the metal patterned template. When there is no glue residue on the PC template and the optical pattern on the PET film is intact, the peelability is excellent.

[0047] The peelability test method is as follows: apply glue evenly to one end of the PC template, cover it with an optical PET film, use a pressure roller to press it from the glued end to the other end, and then irradiate it under an 800mw / cm×cm UV lamp for 2 seconds before peeling off the PET film. The glue is distributed on the PET film and separates from the PC template. Check under a microscope whether there is any glue residue on the PC template and check whether the optical pattern on the PET is complete.

[0048] 2. Adhesion test

[0049] The adhesion of cured adhesive to PC film was tested using a cross-cut adhesion tester. No peeling was observed under a magnifying glass, which was considered a 5B result.

[0050] 3. Comparison under high humidity conditions

[0051] In environments with significantly higher humidity than normal, the adhesion of the membrane product obtained in the comparative example was significantly worse than that in the example, with Example 1 being the best.

[0052]

[0053] In summary, the improved adhesive formula, combined with the film application machine, significantly optimized the film application quality and expanded the application range of the film products.

[0054] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A film bonding process for bonding free-form surfaces, characterized in that, The film application process includes the following steps: Step (1) Print adhesive on the surface of the release film to form an adhesive layer; Step (2) Let the sample stand to allow the air bubbles on the adhesive layer to burst automatically; Step (3) Degas the adhesive layer, perform initial curing, and remove excess adhesive; Curing after step (4); Step (5) Apply a film to the sample; The step (5) involves applying a film to the sample using a specially designed film-applying device for bonding free-form surfaces, which is operated in conjunction with computer operation. The special film-applying device used in step (5) for applying film to free-form surfaces includes a mounting sleeve (1), two sets of bolts (2), two sets of first connecting rods (3), two sets of second connecting rods (4), a sliding sleeve (5), a fixing rod (6), a driving device, a rotating mechanism, a telescopic device, and a film-applying device. The upper part of the front and rear ends of the mounting sleeve (1) are connected with threaded holes. The two sets of bolts (2) are threadedly connected to the two sets of threaded holes of the mounting sleeve (1). One end of the two sets of first connecting rods (3) is rotatably installed on the front and rear ends of the mounting sleeve (1), and the other end of the two sets of first connecting rods (3) is rotatably connected to the top of the two sets of second connecting rods (4). The bottom end of the two sets of second connecting rods (4) is rotatably connected to the front and rear ends of the sliding sleeve (5). The fixing rod (6) is installed at the bottom end of the mounting sleeve (1). The sliding sleeve (5) is slidably connected to the fixing rod (6). The driving device is installed inside the fixing rod (6). The rotating mechanism is installed on the sliding sleeve (5). The telescopic device is installed at the bottom of the rotating mechanism. The film-applying device is installed on the telescopic device. The driving device includes a first electric push rod (7) and a V-shaped frame (8). A through groove (9) is provided in the middle of the fixed rod (6). The first electric push rod (7) is installed at the top of the through groove (9). The V-shaped frame (8) is installed at the output end of the first electric push rod (7). The V-shaped frame (8) corresponds to the positions of the two sets of first connecting rods (3). A rubber pad is provided at the top of the V-shaped frame (8). The rotating mechanism includes two sets of connecting plates (10), four sets of rivets (11), a rotating ring (12), a fixed gear (13), multiple sets of rollers (14), a drive gear (15), and a motor (16). The two sets of connecting plates (10) are installed on the left and right ends of the sliding sleeve (5) by the four sets of rivets (11). The fixed gear (13) is installed on the bottom end of the two sets of connecting plates (10). The fixed gear (13) has a groove on its outer side. The rotating ring (12) is slidably engaged with the groove on the outer side of the fixed gear (13) by the multiple sets of rollers (14). The motor (16) is installed on the outer end of the rotating ring (12). The drive gear (15) is installed on the output end of the motor (16). The drive gear (15) meshes with the fixed gear (13). The telescopic device is installed on the rotating ring (12). The telescopic device includes three sets of second electric push rods (17), three sets of connecting blocks (18), three sets of third connecting rods (19), three sets of guide rails (20) and three sets of sliders (21). The three sets of second electric push rods (17) are equally installed on the outer end of the rotating ring (12). The three sets of connecting blocks (18) are respectively installed on the output end of the three sets of second electric push rods (17). The three sets of third connecting rods (19) are respectively installed on the three sets of connecting blocks (18). The three sets of guide rails (20) are equally installed on the bottom end of the rotating ring (12). The three sets of sliders (21) are respectively connected to the three sets of third connecting rods (19). The three sets of sliders (21) slide on the three sets of guide rails (20). The film application device is installed on the bottom end of the three sets of sliders (21). The film application device includes three sets of support rods (22), three sets of springs (23), three sets of support frames (24), and three sets of flattening rollers (25). The three sets of support rods (22) are respectively installed at the bottom of the three sets of sliders (21). A third electric push rod (26) is installed between the bottom of the slider (21) and the spring (23). The bottom of the three sets of support rods (22) is provided with a telescopic groove. The three sets of support frames (24) are slidably connected to the telescopic grooves of the three sets of support rods (22). The three sets of springs (23) are respectively sleeved on the three sets of support frames (24). One end of the three sets of springs (23) is connected to the three sets of support rods (22), and the other end of the three sets of springs (23) is connected to the three sets of support frames (24). The three sets of flattening rollers (25) are rotatably installed at the bottom of the three sets of support frames (24).

2. The film bonding process for free-form surface bonding according to claim 1, characterized in that: The adhesive mentioned in step (1) is an adhesive suitable for applying film, and the thickness of the adhesive layer is between 15-30µm.

3. The film bonding process for free-form surface bonding according to claim 1, characterized in that: Step (2) Allow the sample to stand under atmospheric pressure to allow the bubbles to burst automatically for 20-60 minutes; Step (3) initial curing involves exposing the semi-finished product and the fixing fixture to ultraviolet light to locally cure the adhesive layer. When removing excess adhesive, use a lint-free cloth soaked in alcohol to wipe the excess adhesive on the semi-finished product. Step (4) post-curing involves placing the semi-finished product and the fixing fixture into a UV exposure machine or UV tunnel oven for final curing.

Images