Recyclable composite protective film
Through the composite structure of cast polypropylene layer and bidirectional tensile polypropylene layer, combined with nanotexture and antistatic layer, the problem of lifting the polypropylene protective film during heat shrinkage is solved, and its mechanical properties and thermal stability are improved, thus achieving Recyclability and durability.
Patent Information
- Application Number
- CN202420244290.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-01
- Publication Date
- 2025-01-07
- Estimated Expiration
- 2034-02-01
AI Technical Summary
The existing polypropylene protective film is prone to heat shrinkage and curling problems during heat shrinkage, which affects its recyclability and mechanical properties.
The composite structure of cast polypropylene layer and bidirectional tensile polypropylene layer is adopted, combining nanotexture and antistatic layer to improve adhesion and thermal stability between the substrate layer and the glue layer, and prevent the curling phenomenon when the glue layer is cured. .
Improve the stiffness, mechanical properties and thermal stability of the protective film, realize the recyclability and durability of the protective film, avoid the problem of curing the adhesive layer, and reduce heat through light reflection, further improve thermal stability sex.
Smart Images
Figure CN222313048U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of film production, in particular to a recyclable composite protective film. Background Art
[0002] With the rapid development and popularization of electronic products, protective films are widely used to protect product screens. Protective films usually include a substrate layer and an adhesive layer. The materials of the substrate layer include PET, PI, PVC, PC, PP and PE. As people's environmental awareness becomes stronger and stronger, protective films made of polypropylene are more conducive to recycling. However, polypropylene has poor temperature resistance. When the adhesive is coated on the surface of the polypropylene substrate layer and then cured, problems such as heat shrinkage of the protective film are prone to occur.
[0003] Therefore, it is necessary to improve the protective film in the prior art. Utility Model Content
[0004] The purpose of the utility model is to overcome the defects existing in the prior art and provide a recyclable composite protective film. The protective film is composited with a cast polypropylene layer and a biaxially oriented polypropylene layer to achieve the recyclability of the protective film, improve the stiffness and mechanical properties of the protective film, and also improve the thermal stability, thereby effectively preventing the protective film from warping when the adhesive layer is cured; the adhesion between the adhesive layer and the substrate layer and the heat of the light part are improved by nano-texturing, thereby further improving the thermal stability of the protective film structure.
[0005] In order to achieve the above technical effects, the technical solution of the utility model is: a recyclable composite protective film, comprising:
[0006] The substrate layer is a polypropylene composite film;
[0007] The adhesive layer is a silicone pressure-sensitive adhesive and is connected to the substrate layer;
[0008] The substrate layer comprises a laminated structure of a cast polypropylene layer and a biaxially oriented polypropylene layer, the biaxially oriented polypropylene layer comprises a high temperature resistant surface layer, the surface of the high temperature resistant surface layer is provided with nano texture, and the adhesive layer is connected to the high temperature resistant surface layer.
[0009] A preferred technical solution is that the substrate layer is a composite of a cast polypropylene layer and a biaxially stretched polypropylene layer, or a laminated structure of a biaxially stretched polypropylene layer, a cast polypropylene layer and a biaxially stretched polypropylene layer.
[0010] A preferred technical solution is that the substrate layer includes an anti-fouling surface layer opposite to the high temperature resistant surface layer, the anti-fouling surface layer is a surface layer of a cast polypropylene layer or a surface layer of a biaxially stretched polypropylene layer, the cast polypropylene layer or the biaxially stretched polypropylene layer includes a polypropylene core layer connected to the anti-fouling surface layer, and the anti-fouling surface layer is a metallocene polyethylene layer.
[0011] A preferred technical solution is that an antistatic layer is provided between the high temperature resistant surface layer of the substrate layer and the adhesive layer.
[0012] A preferred technical solution is that the adhesive layer includes an adhesion layer and an adhesion-enhancing adhesive layer, and the adhesion layer is sandwiched between the substrate layer and the adhesion-enhancing adhesive layer.
[0013] A preferred technical solution is that an antistatic release film is provided on the surface of the adhesive layer away from the substrate layer.
[0014] A preferred technical solution is that the thickness of the substrate layer is 30 to 120 μm, and the thickness of the adhesive layer is 10 to 15 μm.
[0015] The advantages and beneficial effects of the utility model are:
[0016] The recyclable composite protective film has a reasonable structure. The protective film is composited by a cast polypropylene layer and a biaxially oriented polypropylene layer to improve the stiffness and mechanical properties of the protective film, optimize the practicality and durability of the protective film, and improve the thermal stability of the protective film structure in combination with a high-temperature resistant surface layer, thereby preventing the protective film from warping when the adhesive layer is cured; the recyclability of the protective film is also achieved; the adhesion between the substrate layer and the adhesive layer is improved by nano-texturing, and the heat of the light energy portion is reduced by light reflection, thereby further improving the thermal stability of the protective film structure. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a schematic diagram of the structure of the recyclable composite protective film of the utility model;
[0018] Figure 2 It is another structural schematic diagram of the recyclable composite protective film of the utility model;
[0019] Figure 3 The utility model is a schematic diagram of a preferred structure of the recyclable composite protective film.
[0020] In the figure: 1. substrate layer; 2. adhesive layer; 1-a. biaxially oriented polypropylene layer; 1-b. cast polypropylene layer; 3. antistatic layer; 4. antistatic release film; 11. high temperature resistant surface layer; 12. antifouling surface layer; 21. adhesion layer; 22. adhesion enhancing adhesive layer; 100. nano texture; 101. first surface layer; 102. second surface layer; 103. third surface layer; 104. fourth surface layer; 110. unit polypropylene layer; 111. first core layer; 112. second core layer. DETAILED DESCRIPTION
[0021] The following is a further description of the specific implementation of the present invention in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.
[0022] The “surface layer” is based on the normal use state of the recyclable composite protective film and is only for the convenience of describing the present invention and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.
[0023] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention of the utility model, unless otherwise specified, the meaning of "plurality" is two or more.
[0024] like Figures 1 to 3 As shown, the utility model discloses a recyclable composite protective film, including a substrate layer 1 and an adhesive layer 2, the substrate layer 1 is a polypropylene composite film, the adhesive layer 2 is a silicone pressure-sensitive adhesive, and is connected to the substrate layer 1, the substrate layer 1 includes a laminated structure of a cast polypropylene layer 1-b and a biaxially stretched polypropylene layer 1-a, the biaxially stretched polypropylene layer 1-a includes a high temperature resistant surface layer 11, the surface of the high temperature resistant surface layer 11 is provided with a nano texture 100, and the adhesive layer 2 is connected to the high temperature resistant surface layer 11.
[0025] The high temperature resistant surface layer 11 is mainly a mixture of polypropylene and polymethylpentene, wherein polymethylpentene is an engineering plastic with excellent transparency, low density, high heat resistance, chemical resistance and good impact resistance, and excellent stability and dimensional stability at high temperatures; polypropylene resin has good mechanical strength, good toughness, easy processing and relatively low cost.
[0026] As an adhesive layer, silicone pressure-sensitive adhesive has excellent transparency and will not affect the display effect when used for screen protection of electronic devices; it has good temperature resistance and remains stable in a wide temperature range. It can withstand certain high temperature environments, such as the heat generated during charging and use of mobile phones or electronic devices, and can maintain flexibility at low temperatures to avoid embrittlement; low stress bonding: silicone pressure-sensitive adhesive generates low internal stress when attached to the protected object, that is, the pressure on the surface of the protected object is small, reducing potential damage caused by stress; easy to peel without residual glue, when removing the protective film, it can ensure easy peeling and almost no glue marks, which is conducive to the reuse of the protective film and the cleaning and maintenance of the surface of the protected object; anti-aging and chemical stability, can maintain performance for a long time in a variety of environments, and effectively resist the influence of ultraviolet radiation, humidity changes and other factors; good electrical insulation performance, suitable for applications that need to prevent static electricity accumulation and provide electrical insulation protection; strong adaptability, can better adapt to the surfaces of objects protected by different materials, including but not limited to glass, plastic (such as polycarbonate, polyethylene terephthalate, etc.) and metal surfaces. As a protective film adhesive layer, silicone pressure-sensitive adhesive can not only provide excellent optical properties and physical protection, but also ensure reliability and durability during the product life cycle.
[0027] After biaxial stretching, the raw material of the biaxially stretched polypropylene layer 1-a improves the mechanical properties of the protective film, such as tensile strength, stiffness and impact resistance. The cast polypropylene layer 1-b has good softness and strong recyclability. The substrate layer 1 obtained by combining the biaxially stretched polypropylene layer 1-a is suitable for laminating flat or curved screens and is not prone to warping.
[0028] The nanotexture 100 obtains a microscopic concave-convex structure on the surface of the high-temperature resistant surface layer 11 through chemical etching and electrochemical treatment, which not only increases the contact area between the substrate layer 1 and the adhesive layer 2 and improves the adhesion, but also reflects light to reduce the heat generated by the light source, thereby alleviating the problem of poor structural stability of the substrate layer caused by high-temperature curing of the adhesive layer.
[0029] like Figure 1As shown, in some embodiments, the substrate layer 1 is a laminated structure of a cast polypropylene layer 1-b and a biaxially oriented polypropylene layer 1-a. The cast polypropylene layer 1-b includes a first surface layer 101, a first core layer 111, and a second surface layer 102 stacked in sequence, and the biaxially oriented polypropylene layer 1-a includes a third surface layer 103, a second core layer 112, and a fourth surface layer 104 stacked in sequence. The cast polypropylene layer 1-b and the biaxially oriented polypropylene layer 1-a are connected by thermal compounding, the second surface layer 102 and the third surface layer 103 are adjacent, the first surface layer 101 and the fourth surface layer 104 are arranged oppositely, the first surface layer 101 is an anti-fouling surface layer 12, the fourth surface layer 104 is a high temperature resistant surface layer 11, and the anti-fouling surface layer 12 is a metallocene polyethylene layer. The main materials of the first core layer 111, the second surface layer 102, the third surface layer 103, and the second core layer 112 are all polypropylene.
[0030] like Figure 2 As shown, in other embodiments, the substrate layer 1 is a laminated structure of a biaxially oriented polypropylene layer 1-a, a cast polypropylene layer 1-b and a composite of a biaxially oriented polypropylene layer 1-a. Among them, the cast polypropylene layer 1-b is composed of three layers of unit polypropylene layers 110, and the unit polypropylene layers 110 on both sides are transition layers to improve the bonding firmness with the biaxially oriented polypropylene layer 1-a; the biaxially oriented polypropylene layer 1-a is a three-layer composite structure, one of the biaxially oriented polypropylene layers 1-a is provided with a high temperature resistant surface layer 11 connected to the adhesive layer 2, and the other biaxially oriented polypropylene layer 1-a is provided with an anti-fouling surface layer 12 opposite to the high temperature resistant surface layer 11, and the anti-fouling surface layer 12 is a metallocene polyethylene layer. The main material of the biaxially oriented polypropylene layer 1-a is polypropylene.
[0031] like Figure 3 As shown, in a preferred embodiment, in order to prevent static electricity from causing dust to fall on the surface of the protective film, which has a negative impact on the adhesion of the adhesive layer and a negative impact on the cleanliness and optical properties of the substrate layer, an antistatic layer 3 is provided between the high temperature resistant surface layer 11 of the substrate layer 1 and the adhesive layer 2. The antistatic layer 3 is made by coating and curing a polythiophene antistatic agent.
[0032] Organic silicon pressure-sensitive adhesive and polypropylene are different types of materials, so the compatibility between the two is usually poor. Therefore, in order to improve the bonding firmness between the substrate layer and the adhesive layer, and to improve the recycling of the protective film, the adhesive layer 2 further includes an adhesion layer 21 and an adhesion-enhancing adhesive layer 22, and the adhesion layer 21 is sandwiched between the substrate layer 1 and the adhesion-enhancing adhesive layer 22. Among them, the adhesion layer 21 is made by adding a coupling agent to the organic silicon pressure-sensitive adhesive to improve the adhesion to the polypropylene substrate layer; or the adhesion layer 21 includes a polar modified organic silicon pressure-sensitive adhesive, and the polar groups include but are not limited to hydroxyl, carboxyl, epoxy and maleic anhydride, which can improve the compatibility with polypropylene, as well as the compatibility and wettability with the substrate layer interface, thereby improving the bonding performance.
[0033] The surface of the adhesive layer 2 away from the substrate layer 1 is provided with an antistatic release film 4. When peeling off the release film of the protective film, dust is prevented from being adsorbed on the surface of the adhesive layer due to static electricity. The antistatic release film 4 includes a PET substrate layer and a release layer, and at least one surface of the PET substrate layer is provided with an antistatic layer, that is, the antistatic release film includes a PET substrate layer, an antistatic layer and a release layer stacked in sequence, or the antistatic release film includes an antistatic layer, a PET substrate layer, an antistatic layer and a release layer stacked in sequence.
[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.
Claims
1. A recyclable composite protective film, comprising: The substrate layer is a polypropylene composite film; The adhesive layer is a silicone pressure-sensitive adhesive and is connected to the substrate layer; It is characterized in that The substrate layer comprises a laminated structure of a cast polypropylene layer and a biaxially oriented polypropylene layer, the biaxially oriented polypropylene layer comprises a high temperature resistant surface layer, the surface of the high temperature resistant surface layer is provided with nano texture, and the adhesive layer is connected to the high temperature resistant surface layer.
2. The recyclable composite protective film according to claim 1, characterized in that: The substrate layer is a composite of a cast polypropylene layer and a biaxially stretched polypropylene layer, or a laminated structure of a biaxially stretched polypropylene layer, a cast polypropylene layer and a biaxially stretched polypropylene layer.
3. The recyclable composite protective film according to claim 2, characterized in that: The substrate layer includes an anti-fouling surface layer opposite to the high temperature resistant surface layer, the anti-fouling surface layer is a surface layer of a cast polypropylene layer or a surface layer of a biaxially stretched polypropylene layer, the cast polypropylene layer or the biaxially stretched polypropylene layer includes a polypropylene core layer connected to the anti-fouling surface layer, and the anti-fouling surface layer is a metallocene polyethylene layer.
4. The recyclable composite protective film according to claim 1, characterized in that: An antistatic layer is arranged between the high temperature resistant surface layer of the substrate layer and the adhesive layer.
5. The recyclable composite protective film according to claim 1, characterized in that: The adhesive layer comprises an adhesive layer and an adhesion-enhancing adhesive layer, and the adhesive layer is sandwiched between the substrate layer and the adhesion-enhancing adhesive layer.
6. The recyclable composite protective film according to claim 1, characterized in that: An antistatic release film is arranged on the surface of the adhesive layer away from the substrate layer.
7. The recyclable composite protective film according to claim 1, characterized in that: The thickness of the substrate layer is 30 to 120 μm, and the thickness of the adhesive layer is 10 to 15 μm.