Infrared physiotherapy composite film based on flexible polymer substrate and preparation method thereof
By preparing far-infrared functional layers of Cr2O3, Fe3O4, and Y2O3 on a flexible polymer substrate, and combining them with interface buffers and protective layers, the flexibility and performance issues of infrared therapy components were solved, enabling long-term stable use in wearable devices.
Patent Information
- Application Number
- CN202511637108.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-10
- Publication Date
- 2026-02-27
AI Technical Summary
Existing infrared therapy components suffer from the problem of balancing flexibility and high performance. Rigid substrates are brittle, flexible films have insufficient performance, and the bonding between the flexible substrate and the functional layer is weak, making it impossible for the products to be used for a long time.
It adopts a flexible polymer substrate, and the far-infrared functional layer is composed of Cr2O3, Fe3O4 and Y2O3. Combined with the interface buffer layer and protective layer design, it ensures that the product has a high proportion and high emissivity in the 4-14μm band, prevents interlayer delamination and cracking, and has antibacterial properties.
This has resulted in flexible and lightweight infrared physiotherapy products suitable for wearable devices, meeting the safety and performance requirements for long-term use.
Smart Images
Figure CN121572680A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of wearable medical devices, and in particular to an infrared physiotherapy composite film based on a flexible polymer substrate and its preparation method, which is mainly used in wearable medical devices and portable physiotherapy products that need to be in direct contact with the human body. Background Technology
[0002] With the development of wearable medical devices and portable physiotherapy products, the market demand for flexible, lightweight, bendable, and even stretchable infrared physiotherapy components is becoming increasingly urgent. However, existing technologies struggle to balance flexibility and high performance, exhibiting a core deficiency: 1. Limitations of rigid substrates: Although glass-based physiotherapy components are stable in performance, they are brittle, heavy, and inflexible, making them unsuitable for irregular body surfaces such as joints and necks or wearable devices, thus limiting their application scenarios.
[0003] 2. Insufficient performance of flexible films: Existing flexible heating films based on PI or PET are mostly designed for industrial or household appliances. Their infrared radiation bands are not precisely controlled (the 4-14μm "life band" usually accounts for less than 60%), and the protective layer is mostly ordinary PET film or epoxy resin coating. Long-term use can easily soften and stick to the skin, and there is no antibacterial design. Sweat penetration can easily breed bacteria. None of them have passed biocompatibility certification (ISO 10993-1). Direct contact with sensitive skin can easily cause redness, swelling and allergies.
[0004] 3. Challenges in bonding flexible substrates with functional layers: Polymer substrates have poor temperature resistance and low surface energy, resulting in weak bonding with high-performance metal oxide functional layers. They are prone to delamination and rapid performance degradation under repeated bending or thermal cycling, making it difficult to guarantee the long service life of the product.
[0005] Therefore, it is necessary to design a new technical solution to solve the above problems. Summary of the Invention
[0006] In view of this, the present invention addresses the deficiencies of the existing technology, and its main objective is to provide an infrared physiotherapy composite film based on a flexible polymer substrate and its preparation method. The far-infrared functional layer is prepared from the following raw materials by mass percentage: Cr2O3 55%-65%, Fe3O4 35%-45%, and Y2O3 0.5-2%. This structure ensures a high proportion (≥75%) of far-infrared coverage in the 4-14μm wavelength band and a high emissivity (≥0.85). Using a flexible polymer substrate, the product is flexible, lightweight, and perfectly suited for wearable physiotherapy clothing, portable physiotherapy patches, smart protective gear, and other fields. The interface buffer layer design solves the problem of thermal expansion mismatch between layers, ensuring no delamination or cracking after long-term hot and cold cycling. The protective layer design provides antibacterial properties, meeting safety standards for direct skin contact.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: An infrared therapy composite membrane based on a flexible polymer substrate includes, from bottom to top, a flexible polymer substrate, a far-infrared functional layer, a patterned flexible electrode layer, an interface buffer layer, and a flexible protective layer; wherein: The far-infrared functional layer is prepared from the following raw materials by mass percentage: Cr2O3 55%-65%, Fe3O4 35%-45%, Y2O3 0.5-2%; The interface buffer layer includes a flexible optical adhesive and an inorganic oxide layer arranged sequentially from top to bottom; The protective layer includes a flexible membrane substrate, an infrared anti-reflective film disposed on the upper surface of the flexible membrane substrate, and an antibacterial coating disposed on the lower surface of the flexible membrane substrate.
[0008] As a preferred embodiment, the flexible polymer substrate is one or at least two composite structures selected from PET, PI, PC, PTFE, and polyolefins.
[0009] As a preferred embodiment, the far-infrared functional layer is prepared from the following raw materials by mass percentage: Cr2O3 60%, Fe3O4 39%, Y2O3 1%.
[0010] As a preferred embodiment, the flexible electrode layer is an electrode formed of a metal mesh, metal nanowires, or conductive ink.
[0011] As a preferred embodiment, the interface buffer layer further includes an inorganic oxide layer located between the flexible optical adhesive and the patterned flexible electrode layer.
[0012] As a preferred embodiment, the flexible film substrate is a TPU film, a silicone film, or a flexible polyimide film.
[0013] As a preferred embodiment, the infrared antireflection film is a ZnS / MgF2 antireflection film, and the antibacterial coating is a 0.2wt% silver ion antibacterial coating.
[0014] A method for preparing an infrared therapy composite film based on a flexible polymer substrate, comprising the following steps: Step 1: Surface pretreatment of the flexible polymer substrate; Step 2: Form a far-infrared functional layer on the upper surface of the pretreated flexible polymer substrate using a physical vapor deposition process; Step 3: Form a patterned flexible electrode layer on the upper surface of the far-infrared functional layer; Step 4: Form an interface buffer layer on the upper surface of the patterned flexible electrode layer; Step 5: The flexible protective layer is laminated to the upper surface of the interface buffer layer through a hot-press curing process.
[0015] As a preferred option, the pretreatment of the flexible polymer substrate is as follows: PET film is selected as the flexible polymer substrate, and the surface is cleaned and activated by O2 plasma at a power of 200W for 60s, followed by the application of a layer of silane coupling agent as a primer. Preparation of far-infrared functional layer: A composite target containing Cr2O3, Fe3O4 and Y2O3 is used to form a far-infrared functional layer on the upper surface of PET film by high-power pulsed magnetron sputtering, with a substrate temperature ≤60℃. Preparation of patterned flexible electrode layer: Electrodes are directly formed on the upper surface of far-infrared functional layer by screen printing conductive silver paste. After the pattern is cured, it is cured in an oven at 80°C for 30 minutes. Fabrication of the interface buffer layer: Flexible optical adhesive is directly bonded to the upper surface of the patterned flexible electrode layer; Hot pressing of the protective layer: hot pressing for 10 minutes at a temperature of 70℃ and a pressure of 0.5MPa.
[0016] As a preferred option, the pretreatment of the flexible polymer substrate involves selecting a PI film as the flexible polymer substrate and cleaning and activating the surface with Ar / O2 plasma. Preparation of far-infrared functional layer: A composite target containing Cr2O3, Fe3O4 and Y2O3 is used to form a far-infrared functional layer on the upper surface of PI film by magnetron sputtering, with a substrate temperature ≤180℃.
[0017] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, as can be seen from the above technical solution: The far-infrared functional layer is mainly composed of the following raw materials by mass percentage: Cr2O3 55%-65%, Fe3O4 35%-45%, and Y2O3 0.5-2%. This structure ensures a high proportion of ≥75% in the 4-14μm wavelength band and a high emissivity ≥0.85. Using a flexible polymer substrate, the product is flexible, lightweight, and perfectly suited for wearable physiotherapy clothing, portable physiotherapy patches, smart protective gear, and other fields. The interface buffer layer design solves the problem of thermal expansion mismatch between layers, ensuring no delamination or cracking after long-term hot and cold cycles. The protective layer design provides antibacterial properties and meets the safety standards for direct skin contact.
[0018] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the general structure of a preferred embodiment of the present invention; Figure 2 This is a flowchart illustrating the preparation process of a preferred embodiment of the present invention; Figure 3 This is a top view schematic diagram of a preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the general structure of a preferred embodiment of the present invention; Figure 5 This is a top view of a preferred embodiment of the present invention.
[0020] Explanation of reference numerals in the attached diagram: 10. Flexible polymer substrate; 20. Far-infrared functional layer; 30. Patterned flexible electrode layer; 40. Interface buffer layer; 41. Flexible optical adhesive; 42. Inorganic oxide layer; 50. Flexible protective layer; 51. Flexible membrane substrate; 52. Infrared antireflection film; 53. Antibacterial coating. Detailed Implementation
[0021] First, it should be noted that in the description of this invention, the terms "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0022] Please refer to Figures 1 to 5 As shown, it illustrates the specific structure of various preferred embodiments of the present invention, including a flexible polymer substrate 10, a far-infrared functional layer 20, a patterned flexible electrode layer 30, an interface buffer layer 40, and a flexible protective layer 50 stacked sequentially from bottom to top.
[0023] The flexible polymer substrate 10 is one or more composite structures of PET, PI, PC, PTFE, and polyolefin. Example 1: The flexible polymer substrate 10 is a PET film with a thickness of 125 μm; Example 2: The flexible polymer substrate 10 is a PI film with a thickness of 75 μm.
[0024] Among them, PI is suitable for scenarios with extremely high temperature resistance requirements, can withstand higher process temperatures, and achieve better crystallinity of functional layers; PET achieves the best balance between cost and performance, has good optical properties, and is the preferred choice for consumer products; PC is suitable for applications requiring high impact resistance and toughness; PTFE has the theoretical potential to achieve the highest radiation efficiency due to its extremely low absorption rate in the far-infrared band.
[0025] The far-infrared functional layer 20 is disposed on the upper surface of the flexible polymer substrate 10. The far-infrared functional layer 20 is prepared from the following raw materials by mass percentage: Cr2O3 55%-65%, Fe3O4 35%-45%, Y2O3 0.5-2%; specifically, the far-infrared functional layer 20 is prepared from the following raw materials by mass percentage: Cr2O3 60%, Fe3O4 40%, Y2O3 1%, with a 4-14μm band proportion of 76% and an 8-14μm emissivity of 0.86. In Example 1, the thickness of the far-infrared functional layer 20 is 150nm; in Example 2, the thickness of the far-infrared functional layer 20 is 200nm.
[0026] During development, the potential impact of adding elements such as tin (Sn), antimony (Sb), gallium (Ga), indium (In), zinc (Zn), manganese (Mn), and nickel (Ni) to the far-infrared functional layer 20 was studied. The study found that although these elements may bring marginal improvements in some aspects (such as fine-tuning conductivity, wavelength, or stability), they all introduce new complexities, such as a sharp increase in cost and increased difficulty in process control. Most importantly, they will damage the core electrothermal radiation performance balance already achieved by the Cr2O3-Fe3O4-Y2O3 composite system. For example, the introduction of Zn and Ni will significantly reduce conductivity, while In is expensive. In the Cr2O3-Fe3O4-Y2O3 composite system, Fe3O4 solves the basic conductivity and mid-wave radiation, and Y2O3 precisely solves the long-term wavelength stability of Cr2O3 without the need to introduce the above-mentioned additional elements, thus achieving the best balance between performance, cost, and process complexity.
[0027] The patterned flexible electrode layer 30 is disposed on the upper surface of the far-infrared functional layer 20. In embodiment one, the patterned flexible electrode layer 30 is a strip electrode formed from a metal mesh, metal nanowires, or conductive ink, with a thickness of 8 μm and a sheet resistance ≤0.1 Ω / □. In embodiment two, the patterned flexible electrode layer 30 is a copper interdigitated electrode with a thickness of 10 μm. The size of the far-infrared functional layer 20 is smaller than the sizes of the flexible polymer substrate 10, the interface buffer layer 40, and the flexible protective layer 50, so that the flexible polymer substrate 10, the interface buffer layer 40, and the flexible protective layer 50 can seal and fix the far-infrared functional layer 20. Correspondingly, the patterned flexible electrode layer 30 is arranged within the area enclosed by the far-infrared functional layer 20.
[0028] The interface buffer layer 40 includes a flexible optical adhesive 41, which is an OCA optical adhesive. Specifically, in Embodiment 1, the interface buffer layer 40 consists only of the flexible optical adhesive 41. In Embodiment 2, an inorganic oxide layer 42 is further disposed between the flexible optical adhesive 41 and the patterned flexible electrode layer 30. The inorganic oxide layer 42 is a silicon dioxide layer. The thickness of the silicon dioxide layer is 75 nm, and the thickness of the OCA optical adhesive is 25 μm.
[0029] The flexible protective layer 50 includes a flexible membrane substrate 51, an infrared antireflection film 52 disposed on the upper surface of the flexible membrane substrate 51, and an antibacterial coating 53 disposed on the lower surface of the flexible membrane substrate 51. The flexible membrane substrate 51 is a TPU film, a silicone film, or a flexible polyimide film. Specifically, the infrared antireflection film 52 is a ZnS / MgF2 antireflection film, the antibacterial coating 53 is a 0.2wt% silver ion antibacterial coating, and the flexible membrane substrate 51 is a TPU film with a thickness of 50μm. When it is a ZnS antireflection film, its thickness is 70nm, and when it is a MgF2 antireflection film, its thickness is 50nm.
[0030] The preparation method of infrared therapy composite glass is described in detail below: Example 1: Step 1: Surface pretreatment of flexible polymer substrate 10 is performed. A 125μm thick heat-resistant PET film is selected and its surface is cleaned and activated by O2 plasma at a power of 200W for 60s. Then, a layer of silane coupling agent is spin-coated as a primer to further enhance adhesion. Step 2: A far-infrared functional layer 20 is formed on the upper surface of the flexible polymer substrate 10 by physical vapor deposition. A composite target containing Cr2O3, Fe3O4 and Y2O3 is used. The far-infrared functional layer 20 is formed on the upper surface of the flexible polymer substrate 10 by high-power pulsed magnetron sputtering. The thickness is 150nm and the substrate temperature is ≤60℃. Step 3: A patterned flexible electrode layer 30 is formed on the upper surface of the far-infrared functional layer 20. Strip electrodes are directly formed on the upper surface of the far-infrared functional layer 20 by screen printing conductive silver paste. After the pattern is cured, it is cured in an oven at 80°C for 30 minutes. Step 4: Form an interface buffer layer 40 on the upper surface of the far-infrared functional layer 20, and directly attach flexible optical adhesive 31 to the upper surface of the inorganic oxide layer 32. Step 5: The flexible protective layer 50 is laminated to the upper surface of the interface buffer layer 40 by hot pressing and curing process, and hot pressing is carried out for 10 minutes at a temperature of 70℃ and a pressure of 0.5MPa. Example 2: Step 1: Surface pretreatment of the flexible polymer substrate 10. Polyimide film is selected as the flexible polymer substrate 10, and the surface is cleaned and activated by Ar / O2 plasma. Step 2: A far-infrared functional layer 20 is formed on the upper surface of the pretreated flexible polymer substrate 10 by physical vapor deposition. A composite target containing Cr2O3, Fe3O4 and Y2O3 is used to form the far-infrared functional layer 20 on the upper surface of the flexible polymer substrate 10 by magnetron sputtering. The substrate temperature is ≤180℃ to obtain better crystal quality. Step 3: A patterned flexible electrode layer 30 is formed on the upper surface of the far-infrared functional layer 20. A copper interdigitated electrode with a thickness of 10μm is formed on the upper surface of the far-infrared functional layer 20 by electroplating. Step 4: An interface buffer layer 40 is formed on the upper surface of the patterned flexible electrode layer 30. First, an inorganic oxide layer 32 is sputtered on the upper surface of the patterned flexible electrode layer 30, and then a flexible optical adhesive 31 is rolled onto the upper surface of the inorganic oxide layer 32. Step 5: The flexible protective layer 50 is bonded to the upper surface of the interface buffer layer 40 by hot pressing and curing process. The hot pressing is carried out for 18 minutes at a temperature of 130℃, a pressure of 10MPa, and a vacuum degree of ≤10Pa.
[0031] The key design focus of this invention is: The far-infrared functional layer is made from the following raw materials by mass percentage: Cr2O3 55%-65%, Fe3O4 35%-45%, Y2O3 0.5-2%. This structure ensures a high proportion of ≥75% in the 4-14μm band and a high emissivity ≥0.85. Using a flexible polymer substrate, the product is flexible, lightweight, and perfectly suited for wearable physiotherapy clothing, portable physiotherapy patches, smart protective gear, and other fields. The interface buffer layer design solves the problem of thermal expansion mismatch between layers, ensuring no delamination or cracking after long-term hot and cold cycling. The protective layer design provides antibacterial properties and meets the safety standards for direct skin contact.
[0032] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.
Claims
1. An infrared physiotherapy composite membrane based on a flexible polymer substrate, characterized in that: It includes, from bottom to top, a flexible polymer substrate, a far-infrared functional layer, a patterned flexible electrode layer, an interface buffer layer, and a flexible protective layer; wherein: The far-infrared functional layer is prepared from the following raw materials by mass percentage: Cr2O3 55%-65%, Fe3O4 35%-45%, Y2O3 0.5-2%; The interface buffer layer includes a flexible optical adhesive; The protective layer includes a flexible membrane substrate, an infrared anti-reflective film disposed on the upper surface of the flexible membrane substrate, and an antibacterial coating disposed on the lower surface of the flexible membrane substrate.
2. The infrared physiotherapy composite membrane based on a flexible polymer substrate according to claim 1, characterized in that: The flexible polymer substrate is one or more composite structures of PET, PI, PC, PTFE, and polyolefins.
3. The infrared physiotherapy composite membrane based on a flexible polymer substrate according to claim 1, characterized in that: The far-infrared functional layer is prepared from the following raw materials by mass percentage: Cr2O3 60%, Fe3O4 39%, Y2O3 1%.
4. The infrared physiotherapy composite membrane based on a flexible polymer substrate according to claim 1, characterized in that: The flexible electrode layer is an electrode formed from a metal mesh, metal nanowires, or conductive ink.
5. The infrared physiotherapy composite membrane based on a flexible polymer substrate according to claim 1, characterized in that: The interface buffer layer also includes an inorganic oxide layer located between the flexible optical adhesive and the patterned flexible electrode layer.
6. The infrared physiotherapy composite membrane based on a flexible polymer substrate according to claim 1, characterized in that: The flexible film substrate is a TPU film, a silicone film, or a flexible polyimide film.
7. The infrared physiotherapy composite membrane based on a flexible polymer substrate according to claim 1, characterized in that: The infrared antireflection film is a ZnS / MgF2 antireflection film, and the antibacterial coating is a 0.2wt% silver ion antibacterial coating.
8. A method for preparing an infrared physiotherapy composite film based on a flexible polymer substrate, characterized in that: The preparation of an infrared physiotherapy composite membrane based on a flexible polymer substrate as described in any one of claims 1 to 7 comprises the following steps: Step 1: Surface pretreatment of the flexible polymer substrate; Step 2: Form a far-infrared functional layer on the upper surface of the pretreated flexible polymer substrate using a physical vapor deposition process; Step 3: Form a patterned flexible electrode layer on the upper surface of the far-infrared functional layer; Step 4: Form an interface buffer layer on the upper surface of the patterned flexible electrode layer; Step 5: The flexible protective layer is laminated to the upper surface of the interface buffer layer through a hot-press curing process.
9. The method for preparing an infrared physiotherapy composite film based on a flexible polymer substrate according to claim 8, characterized in that: Pretreatment of flexible polymer substrate: PET film was selected as the flexible polymer substrate. The surface was cleaned and activated by O2 plasma at a power of 200W for 60s. Then, a layer of silane coupling agent was applied as a primer. Preparation of far-infrared functional layer: A composite target containing Cr2O3, Fe3O4 and Y2O3 is used to form a far-infrared functional layer on the upper surface of PET film by high-power pulsed magnetron sputtering, with a substrate temperature ≤60℃. Preparation of patterned flexible electrode layer: Electrodes are directly formed on the upper surface of far-infrared functional layer by screen printing conductive silver paste. After the pattern is cured, it is cured in an oven at 80°C for 30 minutes. Fabrication of the interface buffer layer: Flexible optical adhesive is directly bonded to the upper surface of the patterned flexible electrode layer; Hot pressing of the protective layer: hot pressing for 10 minutes at a temperature of 70℃ and a pressure of 0.5MPa.
10. The method for preparing an infrared physiotherapy composite film based on a flexible polymer substrate according to claim 8, characterized in that: Pretreatment of flexible polymer substrate: PI film was selected as the flexible polymer substrate, and the surface was cleaned and activated by Ar / O2 plasma; Preparation of far-infrared functional layer: A composite target containing Cr2O3, Fe3O4 and Y2O3 is used to form a far-infrared functional layer on the upper surface of PI film by magnetron sputtering, with a substrate temperature ≤180℃.