Mass transfer film and method for manufacturing the same
The mass transfer film with a support and buffer layer structure addresses the issues of die sinking and adhesive residue in micro/minimum LED displays, enhancing peeling efficiency and reducing damage, thus improving production quality.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Filing Date
- 2025-12-02
- Publication Date
- 2026-07-09
AI Technical Summary
In existing mass transfer processes for micro/minimum LED displays, micro/minimum LEDs often sink into the adhesive layer of the mass transfer film, leading to issues such as difficulty in peeling, die breakage, and adhesive residue.
A mass transfer film comprising a substrate layer with a support layer and a buffer layer, where the buffer layer is disposed on the support layer, and an adhesive layer is formed on the buffer layer, preventing excessive sinking and facilitating easy die peeling while reducing adhesive residue.
The film prevents excessive sinking of dies, ensures easy die peeling, avoids die damage, and prevents adhesive residue, thereby improving process yield and production volume.
Smart Images
Figure 2026116177000001_ABST
Abstract
Description
Technical Field
[0001] 1. Field of the Disclosure
[0001] The present invention relates to the field of mass transfer technology, and more particularly to a mass transfer film and a method for manufacturing the mass transfer film.
Background Art
[0002] 2. Description of the Related Art
[0002] Mass transfer technology is one of the important technologies in the manufacturing process of micro / minimum light emitting diode (micro / minimum LED) displays, and has a decisive influence on the process yield and production volume of micro / minimum LED displays. In the existing mass transfer process, the mass transfer film is used as a temporary carrier for holding micro / minimum LEDs, and facilitates the execution of subsequent die transfer processes. However, when micro / minimum LEDs are combined with the existing mass transfer film, the micro / minimum LEDs often sink into the adhesive layer of the mass transfer film. This causes problems such as the inability to peel the micro / minimum LEDs from the mass transfer film, die breakage after separation, or adhesive residue remaining on the LEDs.
Summary of the Invention
Problems to be Solved by the Invention
[0003]
[0003] Therefore, in order to solve the above-mentioned existing problems, it is necessary to improve the mass transfer film in the prior art.
Means for Solving the Problems
[0004]
[0004] In some embodiments of the present application, the mass transfer film includes a substrate layer and an adhesive layer. The substrate layer includes a support layer and a buffer layer. The buffer layer is disposed on the support layer. The adhesive layer is disposed on the buffer layer of the substrate layer.
[0005]
[0005] In some embodiments of this application, a method for manufacturing a mass transfer film includes co-extruding a support layer and a buffer layer to form a base layer, and forming an adhesive layer on the buffer layer of the base layer.
[0006]
[0006] Compared to the prior art, the mass transfer film of the present invention has at least the following technical effects: it prevents the die from sinking excessively into the adhesive layer, facilitates die peeling, avoids die damage, and prevents adhesive residue from remaining after die peeling.
[0007]
[0007] Implementation forms of some embodiments of this utility model can be easily understood by reading the following detailed description while referring to the attached drawings. Note that various structures may not be drawn to scale, and the dimensions of various structures may be arbitrarily increased or decreased for the sake of clarity in the discussion. [Brief explanation of the drawing]
[0008] [Figure 1]
[0008] A schematic diagram of a cross-section of a mass transfer film according to several embodiments of this application is shown. [Figure 2]
[0009] The present application shows schematic diagrams of one or more steps according to several embodiments of the method for manufacturing a mass transfer film. [Modes for carrying out the invention]
[0009]
[0010] Please refer to Figure 1, which shows a schematic cross-sectional view of a mass transfer film 1 according to several embodiments of this application. The mass transfer film 1 of the present invention includes a base layer 10 and an adhesive layer 20.
[0010]
[0011] In some embodiments of this application, as shown in Figure 1, the base layer 10 may include a support layer 11 and a buffer layer 12. In some embodiments of this application, the material of the support layer 11 may include thermoplastic polyolefin (TPO) (e.g., including polypropylene (PP)), ethylene vinyl acetate copolymer (EVA), thermoplastic polyurethane (TPU), or at least two compositions thereof. In some embodiments of this application, the support layer 11 may further include an antistatic agent, a heat stabilizer, an antioxidant, an ultraviolet absorber, a lubricant, or an anti-adhesion agent. In some embodiments of this application, the thickness of the support layer 11 may account for 50% to 70% of the total thickness of the base layer 10. In some embodiments of this application, the Shore hardness of the support layer 11 may be in the range of 60A to 70D. In some embodiments of this application, the melt index of the support layer 11 may be in the range of 10.0 g / 10 min to 25.0 g / 10 min, and the melting point of the support layer 11 may be greater than 130°C.
[0011]
[0012] The buffer layer 12 may be placed on the support layer 11. In some embodiments of this application, the material of the buffer layer 12 may include thermoplastic polyolefin (TPO) (e.g., including polypropylene (PP)), ethylene vinyl acetate copolymer (EVA), thermoplastic polyurethane (TPU), or at least two compositions thereof. In some embodiments of this application, the buffer layer 12 may further include an antistatic agent, a heat stabilizer, an antioxidant, an ultraviolet absorber, a lubricant, or an anti-adhesion agent. In some embodiments of this application, the thickness of the buffer layer 12 may be less than or equal to the thickness of the support layer 11. In some embodiments of this application, the thickness of the buffer layer 12 may account for 30% to 50% of the total thickness of the base layer 10. In some embodiments of this application, the Shore hardness of the buffer layer 12 may be less than the Shore hardness of the support layer 11. In some embodiments of this application, the melt index of the buffer layer 12 may be in the range of 10.0 g / 10 min to 25.0 g / 10 min, and the melting point of the buffer layer 12 may be greater than 130°C.
[0012]
[0013] In some embodiments of this application, the total thickness of the base layer 10 (including the support layer 11 and the buffer layer 12) may be in the range of 50 μm to 150 μm (for example, including 60 μm to 140 μm, 70 μm to 130 μm, 80 μm to 120 μm, or 90 μm to 110 μm). Setting this thickness range can improve the transfer performance of the mass transfer film 1. In some embodiments of this application, the tensile strength of the base layer 10 (including the support layer 11 and the buffer layer 12) may be in the range of 80 MPa to 120 MPa. In addition, in some embodiments of this application, the ratio of the tensile strength of the base layer 10 (including the support layer 11 and the buffer layer 12) in the machine direction to the tensile strength of the base layer in the transverse direction may be in the range of 0.95 to 1.05. In some embodiments of this application, the machine direction may include the calendering direction of the base layer 10, and the transverse direction may include the direction perpendicular to the calendering direction.
[0013]
[0014] The adhesive layer 20 is located on the buffer layer 12 of the substrate layer 10. In some embodiments of this application, the adhesive layer 20 may be an adhesive resin material. In some embodiments of this application, the thickness of the adhesive layer 20 may be less than the thickness of the buffer layer 12 in order to reduce the depth to which the die (e.g., micro / mini LED) sinks into the adhesive layer 20. In some embodiments of this application, the thickness of the adhesive layer 20 may be in the range of 4 μm to 20 μm (e.g., including 4 μm to 16 μm, 4 μm to 12 μm, or 4 μm to 8 μm). In some embodiments of this application, the surface tension of the buffer layer 12 may be 33 dynes / cm (dynes / cm) or more in order to increase the adhesion between the adhesive layer 20 and the buffer layer 12.
[0014]
[0015] In the present invention, the support layer 11 is arranged to provide sufficient support to the die in order to prevent excessive sinking of the die into the adhesive layer 20, thereby promoting easy removal of the die. The buffer layer 12 is arranged to reduce stress concentration on the die during die removal, thereby preventing die breakage. By increasing the adhesive strength between the adhesive layer 20 and the buffer layer 12, it is possible to prevent adhesive residue from remaining after die removal. Therefore, compared to the prior art, the mass transfer film 1 of the present invention has at least the following technical effects: (1) it prevents the die from excessively sinking into the adhesive layer 20, (2) it facilitates die removal, (3) it prevents die breakage, and (4) it prevents adhesive residue from remaining after die removal.
[0015]
[0016] Figure 2 shows schematic diagrams of one or more steps according to several embodiments of the method for manufacturing a mass transfer film of this application.
[0016]
[0017] Referring to Figure 2, the support layer 11 and the buffer layer 12 are co-extruded to form the base material layer 10. The support layer 11 in Figure 2 may be the same as the support layer 11 in Figure 1. The buffer layer 12 in Figure 2 may be the same as the buffer layer 12 in Figure 1. Therefore, the base material layer 10 in Figure 2 may be substantially the same as the base material layer 10 in Figure 1.
[0017]
[0018] Surface treatment is performed on the buffer layer 12 of the substrate layer 10 so that the surface tension of the buffer layer 12 is 33 dynes / cm or more. In some embodiments of this application, the surface treatment method may include corona treatment, plasma treatment, hot air treatment, ozone treatment, or ultraviolet treatment.
[0018]
[0019] Referring to FIG. 1, the adhesive layer 20 is formed on the buffer layer 12 of the base material layer 10. In some embodiments of the present application, the adhesive layer 20 can be formed by uniformly coating a solvent-containing resin-based adhesive on the buffer layer 12 by a coater. In some embodiments of the present application, the coater can include a roll coater, a blade coater, a roll blade coater, an air knife coater, a slot die coater, a bar coater, a gravure coater, or a curtain coater.
[0019]
[0020] After the drying process, a master transfer film 1 as shown in FIG. 1 is obtained.
[0020]
[0021] The present invention will be described in detail through the following examples, but this does not mean that the present invention is limited only to the content disclosed in these examples.
[0021]
[0022] Embodiment 1
[0023] The material of layer A (support layer) is polypropylene (PP) having a Shore hardness of 70D.
[0022]
[0024] The material of layer B (buffer layer) is polypropylene (PP) having a Shore hardness of 64A.
[0023]
[0025] Temperature of the extruder die: 180°C to 200°C
[0026] Thickness ratio (A):(B) is 50 μm:50 μm
[0027] Thickness of the adhesive layer: 5 μm
[0028] Drying conditions of the adhesive layer: Heating at 110°C for 3 minutes
[0024]
[0029] Based on the foregoing process conditions and the manufacturing method of the present invention, the production of the base material layer and the master transfer film of Embodiment 1 is completed.
[0025]
[0030] Embodiment 2
[0031] The material of layer A (support layer) is polypropylene (PP) with a Shore hardness of 70D.
[0026]
[0032] The material for layer B (buffer layer) is ethylene vinyl acetate copolymer (EVA) with a Shore hardness of 22D.
[0027]
[0033] Extruder die temperature: 180℃~200℃
[0034] The thickness ratio (A):(B) is 50 μm:50 μm
[0035] Adhesive layer thickness: 5 μm
[0036] Drying conditions for the adhesive layer: Heat at 110°C for 3 minutes.
[0028]
[0037] Based on the aforementioned process conditions and the manufacturing method of the present invention, the preparation of the substrate layer and mass transfer film of Embodiment 2 is completed.
[0029]
[0038] Embodiment 3
[0039] The material of layer A (support layer) is polypropylene (PP) with a Shore hardness of 70D.
[0030]
[0040] The material for layer B (buffer layer) is thermoplastic polyurethane (TPU) with a Shore hardness of 90A.
[0031]
[0041] Extruder die temperature: 180℃~200℃
[0042] The thickness ratio (A):(B) is 50 μm:50 μm
[0043] Adhesive layer thickness: 5 μm
[0044] Drying conditions for the adhesive layer: Heat at 110°C for 3 minutes.
[0032]
[0045] Based on the aforementioned process conditions and the manufacturing method of the present invention, the preparation of the substrate layer and mass transfer film of Embodiment 3 is completed.
[0033]
[0046] Embodiment 4
[0047] The material of layer A (support layer) is polypropylene (PP) with a Shore hardness of 70D.
[0034]
[0048] The material for layer B (buffer layer) is thermoplastic polyurethane (TPU) with a Shore hardness of 70A.
[0035]
[0049] Extruder die temperature: 180℃~200℃
[0050] The thickness ratio (A):(B) is 50 μm:50 μm
[0051] Adhesive layer thickness: 5 μm
[0052] Drying conditions for the adhesive layer: Heat at 110°C for 3 minutes.
[0036]
[0053] Based on the aforementioned process conditions and the manufacturing method of the present invention, the production of the substrate layer and mass transfer film of Embodiment 4 is completed.
[0037]
[0054] Comparative Example 1
[0055] The material of layer A (support layer) is polypropylene (PP) with a Shore hardness of 70D.
[0038]
[0056] Layer B (buffer layer) is not included.
[0039]
[0057] The thickness ratio (A):(B) is 90 μm:0 μm
[0058] Adhesive layer thickness: 15 μm
[0059] Drying conditions for the adhesive layer: Heat at 110°C for 3 minutes.
[0040]
[0060] Based on the process conditions described above, the preparation of the substrate layer and mass transfer film of Comparative Example 1 is completed.
[0041]
[0061] Comparative Example 2
[0062] Layer A (supporting layer) is not provided.
[0042]
[0063] The material for layer B (buffer layer) is thermoplastic polyurethane (TPU) with a Shore hardness of 70A.
[0043]
[0064] The thickness ratio (A):(B) is 0 μm:100 μm
[0065] Adhesive layer thickness: 5 μm
[0066] Drying conditions for the adhesive layer: Heat at 110°C for 3 minutes.
[0044]
[0067] Based on the process conditions described above, the preparation of the substrate layer and mass transfer film for Comparative Example 2 is completed.
[0045]
[0068] Feature evaluation methods
[0069] (1) Tensile strength
[0070] The size of the test specimen for the base layer is 150 mm x 10 mm. A tensile test is performed on the aforementioned test specimen of the base layer using a tensile testing machine at a test temperature of 25°C under conditions of a gauge length of 75 mm and a crosshead speed of 300 mm / min, and the tensile strength at the breaking point of the test specimen is determined. In order to maintain good transfer accuracy for micro / mini LEDs, the mass transfer film does not undergo deformation or sagging due to tension during transfer. The evaluation method for tensile strength is as follows.
[0046]
[0071] If the tensile strength of the base layer is in the range of 100 MPa to 120 MPa, it is evaluated as ◎; if the tensile strength of the base layer is in the range of 80 MPa to 100 MPa, it is evaluated as ○; and if the tensile strength of the base layer is less than 80 MPa, it is evaluated as ×.
[0047]
[0072] (2) Light transmittance
[0073] The size of the substrate layer test specimen is 50 mm x 50 mm. The light transmittance of the specimen at a wavelength of 355 nm is determined using a color difference photophotometer. The evaluation method for light transmittance is as follows:
[0048]
[0074] If the light transmittance of the substrate layer at a wavelength of 355 nm exceeds 90%, it is evaluated as ○; if the light transmittance of the substrate layer at a wavelength of 355 nm is less than 90%, it is evaluated as ×.
[0049]
[0075] (3) Heat resistance
[0076] The mass transfer film test specimens are 100mm x 10mm in size. These are placed in an oven and baked at 130°C for 60 minutes. They are then removed and allowed to cool at room temperature, after which UV light is applied. Following UV light irradiation, the 180° peel strength is tested using a general-purpose tensile testing machine. The heat resistance evaluation method is as follows:
[0050]
[0077] If the peeling force of the substrate layer after UV light irradiation is less than 50 gf / in, it is evaluated as a pass (PASS). If the peeling force of the substrate layer after UV light irradiation is greater than 50 gf / in, it is evaluated as a fail (NG).
[0051]
[0078] (4) Adhesive residue condition test
[0079] The size of the mass transfer film test specimen is 25mm x 25mm. First, a substrate with a micro / mini LED die on it is prepared, then an adhesive layer is applied to the substrate at room temperature, pressed with a 2KG pressure roller, then irradiated with UV light, and finally peeled off at 180°. Finally, the state of the adhesive residue is observed using an electron microscope.
[0052]
[0080] The process conditions and characteristic evaluation results for Embodiments 1-4 and Comparative Examples 1-2 are summarized in Table 1 below.
[0053] [Table 1]
[0054]
[0081] The embodiments described above illustrate only the principles and effects of the present invention and are not intended to limit the invention. Modifications and changes made by those skilled in the art to the embodiments described above do not depart from the spirit of the invention. The scope of the present invention is as described in the claims below.
Claims
1. A base material layer including a support layer and a buffer layer disposed on the support layer, An adhesive layer disposed on the buffer layer of the substrate layer, A mass transfer film equipped with [a specific feature / feature].
2. The mass transfer film according to claim 1, wherein the material of the support layer comprises a thermoplastic polyolefin, an ethylene vinyl acetate copolymer, a thermoplastic polyurethane, or at least two compositions thereof.
3. The mass transfer film according to claim 1, wherein the material of the buffer layer comprises a thermoplastic polyolefin, an ethylene vinyl acetate copolymer, a thermoplastic polyurethane, or at least two compositions thereof.
4. The mass transfer film according to claim 1, wherein the support layer and the buffer layer contain an antistatic agent, a heat stabilizer, an antioxidant, an ultraviolet absorber, a lubricant, or an anti-adhesion agent.
5. The thickness of the buffer layer is less than or equal to the thickness of the support layer. The mass transfer film according to claim 1, wherein the thickness of the adhesive layer is less than the thickness of the buffer layer.
6. The thickness of the support layer accounts for 50% to 70% of the total thickness of the base material layer. The mass transfer film according to claim 5, wherein the thickness of the buffer layer accounts for 30% to 50% of the total thickness of the substrate layer.
7. The melt index of the support layer is in the range of 10.0 g / 10 min to 25.0 g / 10 min. The melting point of the support layer is above 130°C. The melt index of the buffer layer is in the range of 10.0 g / 10 min to 25.0 g / 10 min. The melting point of the buffer layer is greater than 130°C, the mass transfer film according to claim 1.
8. The Shore hardness of the buffer layer is less than the Shore hardness of the support layer. The Shore hardness of the support layer is in the range of 60A to 70D. The tensile strength of the aforementioned base material layer is in the range of 80 MPa to 120 MPa. The mass transfer film according to claim 1, wherein the ratio of the tensile strength of the base material layer in the mechanical direction to the tensile strength of the base material layer in the transverse direction is in the range of 0.95 to 1.
05.
9. The mass transfer film according to claim 1, wherein the surface tension of the buffer layer is 33 dynes / cm (dynes / cm) or more.
10. A method for manufacturing mass transfer film, The support layer and the buffer layer are co-extruded to form the base layer, Forming an adhesive layer on the buffer layer of the substrate layer, A manufacturing method that includes this.