Composite film, 3D printing equipment and preparation method of composite film

Abstract

The invention relates to a composite film, 3D printing equipment and a preparation method of the composite film. The composite film comprises a transparent soft rubber layer and a barrier layer, a first bonding surface is formed on the lower surface of the soft rubber layer; the upper surface of the barrier layer is bonded with the first bonding surface, and the ultraviolet transmittance of the barrier layer is 50-90%. The invention further relates to 3D printing equipment and a preparation method of the composite film. According to the invention, the transmittance of ultraviolet rays penetrating through the composite film can be effectively controlled, the rapid curing of transparent resin in a short time can be effectively ensured, and the phenomena of atomization, yellowing, darkening and the like of the transparent resin can be effectively avoided, so that the transparency of a printed model is improved, and the final printed model is brighter.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing additive technology, and in particular to a composite film, a 3D printing device and a method for preparing the composite film. Background Art

[0002] Photocuring 3D printing technology mainly uses liquid resin as raw material, and completes the printing process by utilizing the property that liquid resin printing materials solidify under light of specific wavelength and intensity.

[0003] like Figure 1 As shown, the lifting type light-curing 3D printer device generally includes a material box 20, a lift 30 and an exposure module 40 (for emitting ultraviolet rays). The material box 20 needs to be fixed on the frame 10, and a release film 201 is installed at the bottom of the material box 20. The material box 20 is filled with liquid resin 50. When performing 3D printing, the three-dimensional model is first layered to obtain the pattern information of each layer, and then the exposure module 40 at the bottom is used to irradiate each layer of the pattern to be printed through the release film 201 of the material box onto the liquid resin 50. The resin between the bottom plate of the elevator 30 and the release film 201 undergoes a curing reaction when exposed to light to form a cured layer, which will adhere to the bottom plate of the elevator 30 (or adhere to the previous cured layer). After the curing of the light pattern is completed, the elevator 30 drives the cured layer to move a certain distance away from the exposure module 40, and the cured layer and the release film are separated. The space between the cured layer and the release film is refilled with liquid resin, and then the next layer is cured. The iteration is repeated to form a complete print (i.e., a three-dimensional model).

[0004] Transparent 3D models are widely used in the medical field, architectural design, jewelry design and other industries. In the prior art, transparent resin (photosensitive resin) can generally be used as a printing material to print transparent 3D models. Transparent resin has the characteristics of high transparency, high strength and high toughness. It can not only make the 3D printed objects almost completely transparent, but also ensure that the printed objects have excellent durability and can remain stable in various environments. In the medical field, transparent resin can produce models with high transparency and simulate real human tissue. These models not only provide doctors with the convenience of surgical simulation and preoperative discussion, but also help patients better understand the surgical process and expected results; in architectural design, the application of transparent resin breaks the limitations of traditional building materials and provides designers with more innovative inspiration. Through 3D printing technology, designers can create architectural models with unique shapes and transparency, so as to better display their design concepts. In jewelry design, transparent resin can make exquisite jewelry, and its unique transparent texture adds a different charm to jewelry.

[0005] There are many advantages to using transparent resin as printing material to print transparent three-dimensional models, but it is still challenging to print transparent three-dimensional models using traditional light-curing 3D printing technology. For example, the release film used in some light-curing 3D printers is FEP (Fluorinated Ethylene Propylene) film. FEP film is cheap and has a small release force, which is convenient for resin to be separated from it. However, the applicant found that the three-dimensional model printed by FEP film is prone to yellowing, which makes the transparency of the printed model poor, thus bringing some problems. For example, when the printed product is invisible braces, the braces with low transparency are very conspicuous and affect the appearance. Summary of the invention

[0006] Therefore, the technical problem to be solved by the present invention is to improve the transparency of the three-dimensional printing model of the light-curing 3D printing technology in the prior art.

[0007] In order to solve the above technical problems, the present invention provides a composite film, comprising:

[0008] A transparent soft adhesive layer, wherein the lower surface of the soft adhesive layer forms a first bonding surface;

[0009] A non-transparent barrier layer, the upper surface of which is bonded to the first bonding surface, and the ultraviolet transmittance of the barrier layer is 50% to 90%.

[0010] In one embodiment of the present invention, the composite film comprises only one transparent soft adhesive layer and one non-transparent barrier layer.

[0011] In one embodiment of the present invention, the composite film is used for 3D printing of photosensitive resin, and during printing, the lower surface of the barrier layer is the light receiving surface.

[0012] In one embodiment of the present invention, the photosensitive resin is a transparent resin.

[0013] In one embodiment of the present invention, the ultraviolet transmittance of the soft adhesive layer is greater than 90%, and the thickness of the soft adhesive layer is 0.02 mm to 0.3 mm.

[0014] In one embodiment of the present invention, the thickness of the barrier layer is 0.01 mm to 0.3 mm.

[0015] In one embodiment of the present invention, the barrier layer is a PTFE film layer.

[0016] In one embodiment of the present invention, the composite film further comprises a transparent release layer, and a second bonding surface is formed on the upper surface of the soft adhesive layer, and the second bonding surface is bonded to the release layer.

[0017] In one embodiment of the present invention, the ultraviolet transmittance of the release layer is greater than 90%, and the thickness of the release layer is 0.01 mm to 0.3 mm.

[0018] In one embodiment of the present invention, the release layer is a FEP film layer or a PFA film layer.

[0019] The present invention further discloses a 3D printing device, comprising a material box, wherein the material box is a cavity with openings at both ends, and the opening at one end of the cavity is covered by any of the composite films described above.

[0020] The present invention also discloses a method for preparing a composite film, comprising:

[0021] The barrier layer is prepared so that the ultraviolet transmittance of the barrier layer is 50% to 90%, and a colloid material is coated on the upper surface of the barrier layer, and a soft glue layer is formed after the colloid material is cured.

[0022] In one embodiment of the present invention, the colloid material is one or more of silicone, rubber, pressure-sensitive glue, polyurethane glue, epoxy resin glue and polydimethylsiloxane.

[0023] In one embodiment of the present invention, the preparation method further comprises preparing a release layer, and hot-pressing the release layer to a side of the soft adhesive layer away from the barrier layer.

[0024] In one embodiment of the present invention, before the barrier layer and the soft glue layer are combined, the contact surface between the barrier layer and the soft glue layer is roughened; before the release layer and the soft glue layer are combined, the contact surface between the release layer and the soft glue layer is roughened.

[0025] The above technical solution of the present invention has the following advantages compared with the prior art:

[0026] The composite film described in the present invention can effectively control the ultraviolet transmittance passing through the composite film, which can not only effectively ensure that the transparent resin (3D printing material) is quickly cured in a short time, but also reduce the aging speed of the transparent resin, and effectively avoid the transparent resin from atomizing, yellowing and darkening, thereby improving the transparency of the printed model and making the final printed model more transparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0028] Figure 1 It is a structural schematic diagram of a 3D printing device in the prior art;

[0029] Figure 2 is a schematic structural diagram of a composite membrane according to an embodiment of the present invention;

[0030] Figure 3 is a schematic structural diagram of a composite membrane according to another embodiment of the present invention;

[0031] Figure 4 is a comparison diagram of a three-dimensional model printed using a composite film according to an embodiment of the present invention;

[0032] Figure 5 It is a comparison diagram of the printing effects of three-dimensional models printed using the composite film of the present invention and other forms of film layers;

[0033] Description of the accompanying drawings in the specification: 10, frame; 20, material box; 201, release film; 30, elevator; 40, exposure module; 50, liquid resin; 60, composite film; 601, barrier layer; 602, soft glue layer; 6021, first bonding surface; 6022, second bonding surface; 603, release layer; DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use.

[0035] In the description of the present invention, it should be understood that the terms "vertical", "upper", "lower", "top", "side", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] The following will be combined Figure 2-Figure 5 , the structure of this embodiment is further described.

[0038] Embodiment 1

[0039] See also Figure 2 , this embodiment discloses a composite film 60, including a transparent soft glue layer 602 and a non-transparent barrier layer 601;

[0040] The lower surface of the soft rubber layer 602 forms a first bonding surface 6021;

[0041] The upper surface of the barrier layer 601 is bonded to the first bonding surface 6021, and the lower surface of the barrier layer 601 is a light receiving surface, which is used to face the light source-exposure module 40, so that the light emitted by the light source is received by the above-mentioned light receiving surface and enters the composite film 60 and is emitted from the composite film 60;

[0042] The ultraviolet transmittance of the blocking layer 601 is 50% to 90%.

[0043] In the above structure, the blocking layer 601 can block part of the ultraviolet rays, so that the transmittance of ultraviolet rays is reduced to 50% to 90%. The transmitted ultraviolet rays can effectively ensure that the transparent resin (3D printing material) is quickly cured in a short time. At the same time, the ultraviolet intensity will not be too high to accelerate the aging speed of the transparent resin, effectively avoiding the yellowing of the transparent resin, thereby improving the transparency of the printed model and making the final printed model more transparent. The single-layer release film used in the conventional light-curing 3D printer device is made of FEP film, but this FEP film has a high ultraviolet transmittance. The high-intensity ultraviolet rays emitted by the exposure module almost all pass through the FEP film to irradiate the transparent resin in the material box, which will accelerate the atomization and yellowing of the resin, reduce its transparency, and make the printed three-dimensional model no longer transparent but yellow, which cannot meet the use requirements. In the above structure of this embodiment, a composite film is used, and a blocking layer is set in the composite film, which can effectively control the ultraviolet transmittance, thereby effectively improving the above-mentioned atomization and yellowing phenomena.

[0044] In addition, the soft rubber layer 602 itself is elastic, which effectively increases the overall toughness of the composite film 60 and can produce a certain degree of recoverable deformation, making the separation of the resin and the composite film 60 easier to achieve. At the same time, it also makes the composite film 60 less likely to be torn and damaged during the release process, thereby increasing the life of the composite film 60.

[0045] It can be understood that when the composite film 60 is composed only of a barrier layer 601 and a soft glue layer 602, if the soft glue layer 602 is on the top layer, then the upper surface of the soft glue layer 602 (the side facing away from the first bonding surface 6021) acts as a release surface, which is used to contact the resin and separate from the cured resin layer after the resin is cured.

[0046] Preferably, the ultraviolet transmittance of the barrier layer 601 is 50% to 80%.

[0047] Specifically, the ultraviolet transmittance of the blocking layer 601 may be 50%, 52%, 55%, 60%, 65%, 70%, 75%, 80%, etc.

[0048] Furthermore, the UV transmittance of the soft glue layer 602 is greater than 90%, and it can absorb a portion of the UV rays. By cooperating with the blocking layer, the amount of UV rays passing through the exposure module 40 can be controlled to further ensure the transparency of the printed model. At the same time, the amount of UV rays absorbed by it is not too large, so as to avoid the ultraviolet rays that are finally emitted through the composite film 60 having an intensity that is too low and affect the curing speed and curing quality of the resin.

[0049] The barrier layer may be a PTFE film or other white film.

[0050] Preferably, in order to better control the UV transmittance, the blocking layer 601 may be a PTFE (Polytetrafluoroethylene) film layer. The PTFE film layer can not only block part of the UV transmission, but also has good stability, and can maintain stable performance without aging even under long-term exposure to UV rays.

[0051] In some embodiments, the thickness of the barrier layer 601 is 0.01 mm to 0.3 mm, so that it has a more suitable transmittance of ultraviolet rays. If the thickness of the barrier layer 601 is too thin, the ultraviolet shielding effect will be reduced, and the ultraviolet intensity cannot be effectively weakened, so that a good de-yellowing effect cannot be achieved. At the same time, if the thickness is too thin, the strength of the barrier layer will be reduced; if the thickness is too thick, the ultraviolet shielding amount will be too much, which will affect the curing speed of the resin, so that the resin cannot be cured within the specified time, resulting in the previous layer of pattern not being completely cured, and the next layer of pattern has begun to be printed, and uncured resin remains between layers, resulting in whitening of the printed model, and also reducing the printing accuracy of the printable model.

[0052] When the barrier layer 601 is a PTFE film layer, the relationship between its thickness and ultraviolet transmittance is shown in Table 1.

[0053] Table 1 UV transmittance of barrier layers of different thicknesses

[0054] Barrier layer (PTFE) thickness (mm) UV transmittance 0.15 70％ 0.1 74％ 0.045 86％ 0.03 88％

[0055] Optionally, the thickness of the barrier layer 601 is 0.03 mm to 0.1 mm, so as to further ensure the control effect of the barrier layer on the ultraviolet transmittance. The best thickness of the barrier layer 601 is 0.1 mm.

[0056] In some embodiments, the material of the soft adhesive layer is one or more of silicone, rubber, pressure-sensitive adhesive, polyurethane adhesive, epoxy resin adhesive and polydimethylsiloxane.

[0057] In some embodiments, the thickness of the soft glue layer 602 is 0.02 mm to 0.3 mm. If the soft glue layer 602 is too thin, the adhesive force is insufficient; if the soft glue layer 602 is too thick, multiple coatings are required, the coating process is complicated, and the ultraviolet transmittance may be too low, affecting the curing speed of the resin. Preferably, when the composite film adopts a two-layer structure of a soft glue layer and a barrier layer, the thickness of the soft glue layer 602 can be 0.3 mm.

[0058] In some embodiments, the composite film 60 may be composed of only one transparent soft adhesive layer 602 and one non-transparent barrier layer 601 , that is, a two-layer composite structure is adopted.

[0059] The composite film 60 is used for 3D printing of photosensitive resin. During printing, the lower surface of the barrier layer 301 is a light receiving surface. Preferably, the photosensitive resin may be a transparent resin.

[0060] This embodiment also discloses a method for preparing a composite film 60, comprising:

[0061] Prepare the barrier layer 601 , which can be a PTFE film layer with a thickness of 0.01 mm to 0.3 mm. The UV transmittance of the barrier layer 601 is 50% to 90%. Coat the upper surface of the barrier layer 601 with a colloid material, and form a soft rubber layer 602 after the colloid material is cured.

[0062] After the colloid material is coated on the upper surface of the barrier layer 601, it needs to be processed by calendering, so that the colloid material can better fit on the barrier layer 601 and improve the fitting effect.

[0063] Furthermore, before coating the colloid material, the upper surface of the barrier layer 601 may be roughened to enhance the adhesion / adsorption of the surface, which is more conducive to the subsequent adhesion of the soft adhesive layer 602;

[0064] The roughening treatment method can be plasma treatment, corona, sodium treatment, grafting reaction, gas oxidation, radical reaction, high temperature melting, irradiation treatment or other chemical treatment methods.

[0065] Preferably, after the roughening treatment, the dyne value of the roughened surface is greater than 40, so as to ensure the adhesion between the two barrier layers and the soft rubber layer and ensure the composite strength of the two layers.

[0066] In some embodiments, the colloid material is one or more of silicone, rubber, pressure-sensitive glue, polyurethane glue, epoxy resin glue and polydimethylsiloxane.

[0067] Furthermore, after the upper surface of the barrier layer 601 is coated with the colloid material, the composite film 60 needs to be placed in an oven for baking at a temperature greater than 80° C. to improve the viscosity of the soft adhesive layer 602 .

[0068] This example also discloses a 3D printing device, including a material box 20, which is a cavity with openings at both ends. The opening at one end of the cavity is covered by a composite film 60 to close the opening, so that ultraviolet rays emitted by an external light source can pass through the composite film 60 to irradiate the interior of the material box 20.

[0069] To facilitate the connection between the composite film 60 and the material box 20, a clamping assembly is provided at the opening where the material box 20 is connected to the composite film 60, and the edges of the composite film 60 are clamped in the clamping assembly. To facilitate clamping and positioning, the clamping edge of the composite film 60 can be punched, and the punching holes can be round holes, square holes, waist-shaped holes, etc.

[0070] When installing, just Figure 1 The release film 201 at the bottom of the middle material box 20 can be replaced with the composite film 60 .

[0071] Furthermore, the 3D printing device further includes a lift 30 and an exposure module 40 - an external light source (for emitting ultraviolet rays).

[0072] When using the above-mentioned 3D printing device to print a transparent three-dimensional model, liquid transparent resin needs to be injected into the material box 20, and then the exposure module 40 is used to emit ultraviolet rays in the direction of the composite film 60, so that the ultraviolet rays pass through the composite film 60 upward through the lower surface (light receiving surface) of the composite film 60 and irradiate the transparent resin in the material box 20, that is, the exposure module 40 at the bottom is used to irradiate each layer of the three-dimensional model to be printed through the composite film 60 to the transparent resin between the bottom plate of the elevator 30 and the composite film 60, and the transparent resin there is irradiated by light. After that, a curing reaction occurs to form a cured layer, which will adhere to the bottom plate of the elevator (or adhere to the previous cured layer). After the curing of this layer of light pattern is completed, the elevator 30 is driven to rise, so that the elevator 30 drives the cured layer to move a certain distance away from the exposure module 40, driving the cured layer and the composite film 60 to separate. At this time, the resin in the material box 20 is refilled into the space between the composite film 60 and the cured layer on the bottom plate, and then the next layer is cured. The iteration is repeated to finally form a complete three-dimensional model, which is a transparent model.

[0073] Embodiment 2

[0074] See also Figure 3 The main difference between this embodiment and embodiment 1 is that the composite film 60 also includes a transparent release layer 603, and the upper surface of the soft glue layer 602 forms a second bonding surface 6022, the second bonding surface 6022 and the release layer 603 are bonded to each other, and the release layer 603 is a film layer with lower surface energy, which is more conducive to the peeling of the resin solidified layer and the release layer 603, avoiding the peeling process to the solidified layer. This adhesion is beneficial to the resin formation.

[0075] Furthermore, the UV transmittance of the release layer 603 is greater than 90%, and the UV transmittance of the soft adhesive layer 602 is greater than 90%, so as to avoid the UV intensity of the final composite film 60 being too low to affect the curing speed and curing quality of the resin.

[0076] In some embodiments, the thickness of the release layer 603 is 0.01 mm to 0.3 mm. If the thickness of the release layer 603 is too thin, the service life of the release layer 603 will be reduced; if the thickness is too thick, the release layer 603 will be too hard, reducing the overall composite effect of the composite film 60 and affecting the ultraviolet transmittance.

[0077] Preferably, the thickness of the release layer is 0.1 mm.

[0078] In some embodiments, the thickness of the soft adhesive layer 602 is 0.02 mm to 0.05 mm to better ensure its bonding effect.

[0079] Furthermore, the material of the release layer 603 includes one or more of fluorinated ethylene propylene (FEP), polyvinylidene fluoride (PVDF), polymethylpentene (TPX), ethylene-tetrafluoroethylene copolymer (ETFE), soluble polytetrafluoroethylene (PFA), polyimide (PI), polyethylene terephthalate (PET), biaxially oriented polypropylene (BOPP), and polycarbonate (PC).

[0080] Preferably, the release layer 603 is made of FEP (Fluorinated ethylene propene copolymer) film layer or PFA (Polyfluoroalkoxy, perfluoroalkoxy resin) film layer.

[0081] Furthermore, the release layer 603 is made of FEPF film layer or PFA film layer, the soft rubber layer 602 is made of silicone layer, and the barrier layer 601 is made of PTFE film layer. The thickness of each layer is 0.1mm, 0.05mm, and 0.1mm respectively. At this time, the best printing effect is achieved and the transparency of the printed model is better.

[0082] In some embodiments, the composite film 60 may only consist of a transparent release layer 603 , a transparent soft adhesive layer 602 , and a non-transparent barrier layer 601 , that is, a three-layer composite structure is adopted.

[0083] This embodiment also discloses a method for preparing a composite film 60, comprising:

[0084] Prepare a barrier layer 601, the barrier layer 601 may be a PTFE film layer with a thickness of 0.01 mm to 0.3 mm, and the ultraviolet transmittance of the barrier layer 601 is 50% to 90%;

[0085] The upper surface of the barrier layer 601 is roughened to increase the roughness of the upper surface, thereby enhancing the adhesion / adsorption force of the surface and facilitating adhesion with subsequent film layers;

[0086] After the roughening treatment, a colloid material is coated on the upper surface of the barrier layer 601, and the colloid material is solidified to form a soft glue layer 602;

[0087] Prepare a release layer 603, which may be a 0.01 mm to 0.3 mm FEP or PFA film layer, and roughen the lower surface of the release layer 603 to enhance the adhesion / adsorption force of the surface;

[0088] After the soft adhesive layer 602 on the surface of the barrier layer 601 is cured, the barrier layer 601 with the soft adhesive layer 602 and the roughened release layer 603 are laminated by hot pressing, wherein the soft adhesive layer 602 is located between the release layer 603 and the barrier layer 601, the upper surface of the soft adhesive layer 602 and the lower surface (roughened surface) of the release layer 603 are laminated together, and the lower surface of the soft adhesive layer 602 and the upper surface of the barrier layer 601 are laminated together;

[0089] After hot pressing, the release layer 603, the soft adhesive layer 602 and the barrier layer 601 become one, ensuring that there is no delamination even if they are repeatedly pulled during the printing process.

[0090] The roughening treatment method may be plasma treatment, corona, sodium treatment, grafting reaction, gas oxidation, radical reaction, high temperature melting, irradiation treatment or other chemical treatment methods;

[0091] This embodiment also discloses another method for preparing the composite film 60, which differs from the above method in that: first, a release layer 603 is prepared, and after the lower surface of the release layer 603 is roughened, a colloid material is coated on the lower surface of the barrier layer 601, and the soft glue layer 602 is formed after the colloid material is solidified; then, the release layer 603 with the soft glue layer 602 and the prepared barrier layer 601 are hot-pressed to bond the lower surface of the soft glue layer 602 and the upper surface (roughened surface) of the barrier layer 601 together, thereby completing the composite of the release layer 603, the soft glue layer 602 and the barrier layer 601.

[0092] During the compounding process, a precision calender is preferably used to set the corresponding thickness, pressure, tension, and surface temperature of the calender roller, and then the release layer 603, the soft rubber layer 602, and the barrier layer 601 are pressed to a certain thickness.

[0093] In some embodiments, the colloid material is one or more of silicone, rubber, pressure-sensitive glue, polyurethane glue, epoxy resin glue and polydimethylsiloxane.

[0094] See also Figure 4 As shown, Figure 4 The figure shows four examples of printed models a, b, c, and d. The printed models are transparent braces. The composite film 60 in the four examples all adopts a three-layer structure, namely, a release layer 603, a soft glue layer 602, and a barrier layer 601. The release layer 603 adopts a FEP film layer or a PFA film layer. Figure 4 In the figure, the release layer 603 of the composite film of the model located on the upper side is made of FEP film, the release layer 603 of the composite film of the model located on the lower side is made of PFA film, the soft rubber layer 602 is made of silicone layer, and the barrier layer 601 is made of PTFE film;

[0095] In example a, the thicknesses of the release layer 603, the soft adhesive layer 602 and the barrier layer 601 are 0.1 mm, 0.05 mm and 0.1 mm respectively; the printing effect is shown as follows: the printed model is bright and transparent without whitening or yellowing;

[0096] In example b, the thicknesses of the release layer 603, the soft glue layer 602 and the barrier layer 601 are 0.1 mm, 0.05 mm and 0.03 mm respectively, and the printing effect is shown as follows: the printed model is translucent and slightly whitish;

[0097] In example c, the thicknesses of the release layer 603, the soft adhesive layer 602 and the barrier layer 601 are 0.1 mm, 0.05 mm and 0.01 mm respectively, and the printing effect is as follows: the printed model is bright and slightly yellowish;

[0098] In example d, the thicknesses of the release layer 603, the soft adhesive layer 602 and the barrier layer 601 are 0.1 mm, 0.02 mm and 0.03 mm respectively, and the printing effect is shown as follows: the printed model is bright and slightly yellowish;

[0099] It can be seen from the above example that the composite film 60 adopts a three-layer structure of a release layer 603, a soft glue layer 602 and a barrier layer 601, which can effectively improve the transparency of the printed model. When the release layer 603 adopts an FEP film layer or a PFA film layer, the soft glue layer 602 adopts a silicone layer, and the barrier layer 601 adopts a PTFE film layer, and the thickness of each layer is 0.1mm, 0.05mm, and 0.1mm respectively, that is, when a solution of 0.1mm FEP / PFA film layer + 0.05mm silicone layer + 0.1mm PTFE film is adopted, the transparency of the printed model is best.

[0100] See also Figure 5 As shown, Figure 5 A comparison of the three-dimensional model printing using other release films 201 in the above-mentioned embodiments 1 and 2 and the prior art is given. Figure 5 Four printing examples are shown in :

[0101] "AF printing" means that the composite film 60 with a thickness of 0.25 mm in Example 2 is used for printing. The composite film 60 is a composite film layer of "PTFE film layer (barrier layer) + silicone layer + FEP (PFA) film layer (release layer)". The printing effect is: the printed model (tooth braces) is crystal clear;

[0102] “AGF printing” means that the composite film 60 with a thickness of 0.15 mm in the first embodiment is used for printing. The composite film 60 is a composite film layer of “PTFE film layer (barrier layer) + silicone layer”. The printing effect is: the printed model (tooth braces) is crystal clear;

[0103] "ACF printing" means that a film layer with a thickness of 0.15 mm is used for printing. The film layer is a composite film layer of "FEP (PFA) film layer + silicone layer". The printing effect is: the printed model (braces) is slightly foggy, yellowish, and dark;

[0104] "PFA printing" means printing with a single layer of PFA film with a thickness of 0.15mm. Printing effect: the printed model (tooth braces) is foggy, yellowish, and dark;

[0105] "FEP printing" means printing with a single-layer FEP film with a thickness of 0.15 mm. Printing effect: the printed model (braces) is foggy and yellowish;

[0106] Depend on Figure 5 It can be seen from the examples that, compared with the prior art, the composite film structure of the first and second embodiments of the present invention can effectively improve the transparency of the printed model.

[0107] All of the above optional technical solutions can be combined in any way to form optional embodiments of the present invention, that is, any multiple embodiments can be combined to meet the needs of different application scenarios. They are all within the protection scope of this application and will not be described one by one here.

[0108] It should be noted that the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A composite film, characterized in that: include, A transparent soft adhesive layer, wherein the lower surface of the soft adhesive layer forms a first bonding surface; A non-transparent barrier layer, the upper surface of which is bonded to the first bonding surface, and the ultraviolet transmittance of the barrier layer is 50% to 90%.

2. The composite film according to claim 1, characterized in that: The composite film only includes a transparent soft adhesive layer and a non-transparent barrier layer.

3. The composite film according to claim 1, characterized in that The composite film is used for 3D printing of photosensitive resin, and during printing, the lower surface of the barrier layer is a light receiving surface.

4. The composite film according to claim 3, characterized in that The photosensitive resin is a transparent resin.

5. The composite membrane according to claim 1, characterized in that: The ultraviolet transmittance of the soft adhesive layer is greater than 90%, and the thickness of the soft adhesive layer is 0.02 mm to 0.3 mm.

6. The composite membrane according to claim 1, characterized in that: The thickness of the barrier layer is 0.01 mm to 0.3 mm.

7. The composite membrane according to claim 1, characterized in that: The barrier layer is a PTFE film layer.

8. The composite membrane according to claim 1, characterized in that: It also includes a transparent release layer. The upper surface of the soft adhesive layer is formed with a second bonding surface, and the second bonding surface is bonded to the release layer.

9. The composite membrane according to claim 9, characterized in that: The ultraviolet transmittance of the release layer is greater than 90%, and the thickness of the release layer is 0.01 mm to 0.3 mm.

10. The composite membrane according to claim 1, characterized in that: The release layer is a FEP film layer or a PFA film layer.

11. A 3D printing device, characterized in that: It comprises a material box, which is a cavity with openings at both ends, and the opening at one end of the cavity is covered by the composite film according to any one of claims 1 to 10.

12. A method for preparing a composite film, characterized in that: include, The barrier layer is prepared so that the ultraviolet transmittance of the barrier layer is 50% to 90%, and a colloid material is coated on the upper surface of the barrier layer, and a soft glue layer is formed after the colloid material is cured.

13. The preparation method according to claim 12, characterized in that: The colloid material is one or more of silica gel, rubber, pressure-sensitive glue, polyurethane glue, epoxy resin glue and polydimethylsiloxane.

14. The preparation method according to claim 12, characterized in that: The method further includes preparing a release layer, and hot-pressing the release layer to a side of the soft adhesive layer away from the barrier layer.

15. The preparation method according to claim 14, characterized in that: Before the barrier layer and the soft adhesive layer are combined, the contact surface between the barrier layer and the soft adhesive layer is roughened; before the release layer and the soft adhesive layer are combined, the contact surface between the release layer and the soft adhesive layer is roughened.

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