Far infrared radiation coating, coating layer, preparation method and application

Abstract

This invention belongs to the field of far-infrared radiation coating technology, specifically relating to a far-infrared radiation coating, coating method, and application. The raw materials for preparing the coating include modified organosilicon resin, high-structure conductive carbon black, far-infrared composite ceramic powder, flake graphite, dispersant, coupling agent, leveling agent, thixotropic agent, and solvent. The coating prepared by this method exhibits a normal total emissivity of 0.89 in the 2.5-25μm range, a peak radiation wavelength of 8.16μm, and a relative radiation intensity ≥0.95 in the 7.6-8.9μm band at a working temperature of 40-60℃ in a test environment of 20℃ and 48%RH. Furthermore, the coating has low cost, strong adhesion, and good flexibility, making it particularly suitable for the application requirements of flexible substrates such as low-temperature wearable products.

Description

Technical Field

[0001] This invention belongs to the field of far-infrared radiation coating technology, specifically relating to a far-infrared radiation coating, coating method, preparation method, and application. Background Technology

[0002] Far-infrared radiation coatings, with their ability to emit far-infrared light waves, have broad application prospects in consumer fields such as health preservation, physiotherapy, and rehabilitation. Their core function is to emit far-infrared light waves that are compatible with the human body. These waves are absorbed by the skin and subcutaneous tissue, producing a warming and resonance effect, thereby promoting blood circulation, relieving muscle soreness, and dispelling dampness and cold, among other therapeutic and health-preserving effects. However, currently available far-infrared radiation coatings still have many technical defects and shortcomings in practical applications in the health preservation and physiotherapy fields, severely limiting their promotion and application. These are as follows: 1. The high emissivity of most far-infrared coatings can only be demonstrated in high-temperature environments above 100℃. In the comfortable therapeutic temperature range of 40-60℃, their far-infrared emissivity drops significantly, failing to meet the requirements for use in low-temperature application scenarios.

[0003] 2. Currently, most common far-infrared coatings use carbon black, graphite, etc. as functional fillers (e.g., existing technology CN108003701A). The far-infrared emission peak of these coatings is usually concentrated at 7-8μm, which is significantly different from the optimal absorption window of 8-14μm (absorption peak is about 9.5μm). Even if the normal total emissivity is high (e.g. 0.90), the actual amount of effective far-infrared radiation absorbed by the human body is very small, resulting in a poor thermal sensation and failing to achieve the expected health and therapeutic effects.

[0004] 3. Existing far-infrared coatings have problems such as poor adhesion and easy cracking on flexible substrates such as polyimide (PI) films, making it difficult to adapt to the use requirements of flexible substrates such as wearable products; the raw material cost of existing high-performance far-infrared coatings is high, resulting in high product prices and making it difficult to achieve large-scale promotion and application of consumer products.

[0005] Therefore, developing a far-infrared radiation coating that can overcome the above-mentioned defects has become an urgent technical problem to be solved. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a far-infrared radiation coating, coating method and application suitable for low temperature application scenarios of 40-60℃; the coating has a normal total emissivity of 0.89 in the 2.5-25μm range and a relative radiation intensity ≥0.95 in the 7.6-8.9μm band in a test environment of 20℃ and 48%RH, and a working temperature of 40-60℃. Moreover, the coating has low cost, strong adhesion and good flexibility.

[0007] The technical solution adopted by the present invention to solve the above problems is as follows: On one hand, the present invention provides a far-infrared radiation coating, the coating comprising the following raw materials in parts by weight: 40-45 parts modified organosilicon resin, 6-10 parts high-structure conductive carbon black, 20-30 parts far-infrared composite ceramic powder, 10-15 parts flake graphite, 4-6 parts dispersant, 1-2 parts coupling agent, 0.2-0.5 parts leveling agent, 0.5-1.5 parts thixotropic agent, and 10-25 parts solvent.

[0008] Among them, modified organosilicon resin serves as the film-forming matrix, exhibiting heat resistance, flexibility, and good adhesion; high-structure conductive carbon black acts as the main emitter, constructing nano-light traps, which reduces costs by 30% compared to rare earth ceramics (yttrium oxide, zirconium oxide) and graphene used in similar coatings currently on the market; far-infrared composite ceramic powder can enhance light radiation in the 8-14μm range; and flake graphite mainly plays the role of heat conduction and uniform thermal field.

[0009] In the above technical solution, the coating prepared by the above coating material has a normal total emissivity of 0.89 in the 2.5-25μm range when the working temperature is 40-60℃ in a test environment of 20℃ and 48%RH, the radiation peak wavelength of 8.16μm falls exactly within the human absorption window of 8-14μm, and the relative radiation intensity in the 7.6-8.9μm band is 0.95-1.0.

[0010] Furthermore, the modified silicone resin is one or more of polyester-modified silicone resin and polyurethane-modified silicone resin. By introducing polyester or polyurethane segments into the silicone backbone, the modified silicone resin retains the heat resistance, flexibility, and low surface energy of silicone, while enhancing its adhesion to the substrate and compatibility with other fillers.

[0011] Further, preferably, the dispersant is an amine dispersant, the coupling agent is a silane coupling agent, the leveling agent is an organosilicon surface additive, and the thixotropic agent is fumed silica; the above-mentioned additives are commonly used additives in coatings, and their functions will not be elaborated further.

[0012] Further, preferably, the solvent is a mixed solvent of cyclohexanone and dipropylene glycol butyl ether, and the mass ratio of cyclohexanone to dipropylene glycol butyl ether is 2-4:1.

[0013] On the other hand, the present invention provides a method for preparing a far-infrared radiation coating using the above-mentioned far-infrared radiation coating material, the method comprising the following steps: S1. Premixing: The solvent, dispersant, coupling agent, and high-structure conductive carbon black are mixed evenly to obtain material 1; S2. Grinding: Mix material 1 with 40%-60% modified organosilicon resin, and grind to obtain material 2 with a fineness ≤7μm; S3. Adding material: Mix material 2 with the remaining modified silicone resin, far-infrared composite ceramic powder, flake graphite and leveling agent evenly to obtain material 3; S4. Viscosity adjustment: Add thixotropic agent to material 3 and disperse at high speed to obtain material 4; S5. Coating: The material 4 is evenly coated on the substrate and then subjected to step curing treatment to obtain a far-infrared radiation coating.

[0014] Specifically, the substrate can be a flexible substrate or a rigid substrate, such as, but not limited to, polyimide (PI) film, polyester (PET) film, fabric or metal foil.

[0015] In the above technical solution, grinding the far-infrared radiation coating to a particle size of ≤7μm can increase the specific surface area of ​​the functional powder, improve the uniformity of powder dispersion and far-infrared radiation efficiency, and at the same time make the film smooth and dense with excellent adhesion. The step-curing method can make the solvent in the coating evaporate slowly, avoid the generation of air bubbles and pinholes, reduce the internal stress of coating curing, and make the resin cross-linking reaction more complete, taking into account the mechanical properties of the coating and the stability of far-infrared radiation function.

[0016] The coating prepared by the above method has good adhesion and flexibility on flexible substrates, making it very suitable for the application requirements of flexible substrates such as wearable products. The above preparation method is simple, can be produced using existing coating equipment, has strong production adaptability, and can be mass-produced.

[0017] Furthermore, the grinding is basket grinding, and the stepped curing process is as follows: pre-baking at 80-100℃ for 5-10 min → curing at 120-150℃ for 10-20 min → post-curing at 150-170℃ for 5-10 min.

[0018] On the other hand, the present invention provides a far-infrared radiation coating, which is prepared by the above-described method.

[0019] In a test environment of 20℃ and 48%RH, the coating has a normal total emissivity of 0.89 in the 2.5-25μm range and a relative radiation intensity of ≥0.95 in the 7.6-8.9μm band at an operating temperature of 40-60℃. Moreover, the coating has good adhesion and flexibility on flexible substrates, making it very suitable for the application requirements of flexible substrates such as wearable products.

[0020] In another aspect, the present invention provides a far-infrared self-adhesive film, which sequentially includes the far-infrared radiation coating, substrate, adhesive layer, and release layer described above.

[0021] The far-infrared self-adhesive film of the present invention can be directly applied to the surface of any heating element (such as metal heating sheet, graphene heating film, carbon fiber heating film, ceramic heating sheet, etc.) after the release layer is removed during use, which can significantly improve the far-infrared emissivity.

[0022] On the other hand, the present invention provides an application of the above-mentioned far-infrared radiation coating, far-infrared radiation coating, and far-infrared self-adhesive film in physiotherapy and health products, electric heating products, electric heating products, floor heating products, and greenhouse heating products. It is especially suitable for low-temperature wearable products such as heated eye masks, physiotherapy patches, and heated clothing, which can efficiently radiate far-infrared rays and the radiation wavelength is precisely matched to human absorption.

[0023] The present invention has the following beneficial effects: The far-infrared radiation coating of this invention, when tested in a 20°C, 48%RH environment, exhibits a normal total emissivity of 0.89 in the 2.5-25μm range and a peak radiation wavelength of 8.16μm at a working temperature of 40-60°C. The relative radiation intensity in the 7.6-8.9μm band is ≥0.95. More importantly, when the coating operates within the most comfortable therapeutic temperature range of 40-60°C, its peak radiation wavelength closely matches the human body's absorption peak, allowing the radiation energy to be absorbed by the body most efficiently, producing a significant thermal effect and therapeutic effect. It is particularly suitable for low-temperature applications with a working temperature of 40-60°C.

[0024] The coating of this invention has good adhesion and flexibility on flexible substrates, making it very suitable for the use of flexible substrates in wearable products and other similar products.

[0025] The coating of this invention has low raw material cost, simple preparation method, can be produced using existing coating equipment, has strong production adaptability, and can be mass-produced on a large scale.

[0026] The far-infrared self-adhesive film of the present invention can be directly applied to the surface of any heating element (metal heating sheet, graphene heating film, ceramic sheet, etc.) after the release layer is removed, which can significantly improve the far-infrared emissivity.

[0027] The coatings, coatings, and far-infrared self-adhesive films of this invention have a wide range of applications and can be used in physiotherapy and health products, electric heating products, electric heating products, floor heating products, and greenhouse heating products. Attached Figure Description

[0028] Figure 1 The infrared radiation wavelength range curve of the far-infrared radiation coating of the present invention is shown. The test environment was 20℃ and 48%RH. Figure 2 This is a schematic diagram of the far-infrared self-adhesive film structure of the present invention; The components are: 1. far-infrared radiation coating; 2. substrate; 3. adhesive layer; and 4. release layer. Detailed Implementation

[0029] To make the technical problems, solutions, and advantages of this invention clearer, a detailed description will be provided below with reference to specific examples. However, the scope of protection of this invention is not limited to the following specific embodiments. The described embodiments are merely some, not all, of the embodiments of this invention, and are not intended to limit the invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0030] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0031] Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention are commercially available or can be prepared using existing methods. Unless otherwise specified, the parts mentioned in this invention are parts by weight. Example 1

[0032] The far-infrared radiation coating of Example 1 of the present invention comprises the following raw materials in parts by weight: 45 parts modified organosilicon resin, 7 parts high-structure conductive carbon black, 20 parts far-infrared composite ceramic powder, 10 parts flake graphite, 4 parts dispersant, 1 part coupling agent, 0.3 parts leveling agent, 0.7 parts thixotropic agent, and 12 parts solvent.

[0033] Among them, the modified silicone resin is a polyurethane-modified silicone resin with a solid content ≥98%, a viscosity (25℃) of 3000-8000cps, and can withstand curing temperatures above 160℃. Its adhesion to polyimide films has been tested and can reach grade 0. The high-structure conductive carbon black has a DBP oil absorption value ≥110 mL / 100g and a native particle size of 20-30nm. The far-infrared composite ceramic powder is a Fe-Mn-Cu-Co ceramic powder with a D50 of 1-3μm. The flake graphite has a D50 of 3-6.5μm. The dispersant is an amine dispersant, the coupling agent is γ-glycidyl etheroxypropyltrimethoxysilane, the leveling agent is polyether-modified polydimethylsiloxane, the thixotropic agent is hydrophobic fumed silica, and the solvent is a mixed solvent formed by cyclohexanone and dipropylene glycol butyl ether in a mass ratio of 3:1.

[0034] The far-infrared radiation coating of Example 1 is prepared by the following steps: S1. Premixing: The solvent, dispersant, coupling agent, and high-structure conductive carbon black are mixed evenly by stirring to obtain material 1; S2. Grinding: Mix material 1 with half of the modified silicone resin and transfer it to a basket mill. Use 0.3-0.5mm zirconia grinding beads and control the spindle speed of the basket mill to 2500rpm to grind material 2 with a fineness ≤5μm. S3. Adding material: Mix material 2 with the remaining modified silicone resin, far-infrared composite ceramic powder, flake graphite, and leveling agent, and stir for 15 minutes to mix evenly to obtain material 3; S4. Viscosity adjustment: Add thixotropic agent to material 3, wet at low speed for 5 minutes, and then disperse at 1400 rpm for 5 minutes to obtain material 4; S5. Coating: The material 4 is uniformly coated onto a 25μm thick PI film that has undergone plasma treatment (400W power, 50 seconds) using a wire rod coating method. The wet film thickness is controlled to be 65μm, and a far-infrared radiation coating is obtained by step curing treatment. The step curing treatment is as follows: 80℃ pre-baking / 10min → 140℃ curing / 15min → 150℃ post-curing / 8min.

[0035] The far-infrared radiation coating of Example 1 was subjected to the following performance tests: 1. Radiation performance testing The sample was attached to the surface of a heating element with an operating temperature of 40-60℃ to form a specimen. The far-infrared radiation performance of the specimen was commissioned to the National Infrared and Industrial Electric Heating Products Quality Inspection and Testing Center and the Wuhan Product Quality Supervision and Inspection Institute for testing. The testing was conducted in accordance with the standards GB / T 7287-2008 "Test Methods for Infrared Radiation Heaters" and GB / T 18497.2-2019 "Characteristics of Electric Infrared Emitters for Industrial Heating - Part 2: Medium and Long Wave Electric Infrared Emitters".

[0036] 2. Coating adhesion test Coating adhesion was tested according to GB / T 9286-2021 "Cross-cut test for paints and varnishes".

[0037] 3. Coating bending resistance test The flexural strength of the coating was tested according to GB / T 1731-2020 "Determination of Flexibility of Paint Film and Putty Film".

[0038] 4. Resistivity Test The resistivity of the coating was determined according to GB / T 1410-2006 "Test Methods for Volume Resistivity and Surface Resistivity of Solid Insulating Materials".

[0039] from Figure 1It can be seen that, in a test environment of 20℃ room temperature and 48%RH, the far-infrared radiation coating of Example 1 has a normal total emissivity of 0.89 in the 2.5-25μm range (meeting the national standard ≥0.83) at an operating temperature of 40-60℃, a peak radiation wavelength of 8.16μm, and a relative radiation intensity of 0.95-1.0 in the 7.6-8.9μm band. Furthermore, testing showed that the adhesion of the coating of Example 1 to the PI film was grade 0; it showed no cracking after 1000 bends, and its sheet resistance was approximately... .

[0040] The far-infrared radiation coating of this invention exhibits a normal total emissivity of 0.89 in the 2.5-25μm range and a peak radiation wavelength of 8.16μm at an operating temperature of 40-60℃ under test conditions of 20℃ and 48%RH. The relative radiation intensity in the 7.6-8.9μm band is ≥0.95. More importantly, when the coating operates within the most comfortable therapeutic temperature range of 40-60℃, its peak radiation wavelength closely matches the human body's absorption peak, allowing for highly efficient absorption of radiant energy and producing significant thermal and therapeutic effects. This makes it particularly suitable for low-temperature applications at 40-60℃. Furthermore, the coating demonstrates good adhesion and flexibility on flexible substrates, making it ideal for wearable products and other flexible applications. It should be noted that this invention is not simply about increasing emissivity; rather, it represents a systematic design for "wavelength-temperature matching" in low-temperature wearable scenarios, a feature never before revealed in existing technologies. Example 2

[0041] As a specific application, this invention provides a far-infrared self-adhesive film, the structure of which is as follows: Figure 2 As shown, it includes, in sequence, the far-infrared radiation coating 1, the substrate 2, the adhesive layer 3, and the release layer 4.

[0042] This far-infrared self-adhesive film can be directly applied to any heating element surface (metal heating element, graphene heating film, ceramic sheet, etc.) after peeling off the release layer, which can significantly improve the far-infrared emissivity.

[0043] The coatings, coatings, or far-infrared self-adhesive films of the present invention can be applied to physiotherapy and health products, electric heating products, electric heating products, floor heating products, and greenhouse heating products. They are especially suitable for low-temperature wearable products such as heated eye masks, physiotherapy patches, and heated clothing. They can efficiently radiate far-infrared rays, and the radiation wavelength is precisely matched to human absorption.

[0044] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0045] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0046] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A far-infrared radiation coating, characterized in that, The coating comprises the following raw materials in parts by weight: 40-45 parts modified silicone resin, 6-10 parts high-structure conductive carbon black, 20-30 parts far-infrared composite ceramic powder, 10-15 parts flake graphite, 4-6 parts dispersant, 1-2 parts coupling agent, 0.2-0.5 parts leveling agent, 0.5-1.5 parts thixotropic agent, and 10-25 parts solvent.

2. The far-infrared radiation coating according to claim 1, characterized in that, The modified silicone resin is one or more of polyester-modified silicone resin and polyurethane-modified silicone resin.

3. The far-infrared radiation coating according to any one of claims 1-2, characterized in that, The dispersant is an amine dispersant; And / or, the coupling agent is a silane coupling agent; And / or, the leveling agent is an organosilicon surface additive; And / or, the thixotropic agent is fumed silica.

4. The far-infrared radiation coating according to any one of claims 1-2, characterized in that, The solvent is a mixture of cyclohexanone and dipropylene glycol butyl ether, with a mass ratio of cyclohexanone to dipropylene glycol butyl ether of 2-4:

1.

5. A method for preparing a far-infrared radiation coating using the far-infrared radiation coating as described in any one of claims 1-4, characterized in that, The method includes the following steps: S1. Premixing: The solvent, dispersant, coupling agent, and high-structure conductive carbon black are mixed evenly to obtain material 1; S2. Grinding: Mix material 1 with 40%-60% modified organosilicon resin, and grind to obtain material 2 with a fineness ≤7μm; S3. Adding material: Mix material 2 with the remaining modified silicone resin, far-infrared composite ceramic powder, flake graphite and leveling agent evenly to obtain material 3; S4. Viscosity adjustment: Add thixotropic agent to material 3 and disperse at high speed to obtain material 4; S5. Coating: The material 4 is evenly coated on the substrate and then subjected to step curing treatment to obtain a far-infrared radiation coating.

6. The method according to claim 5, characterized in that, The grinding process is basket grinding; And / or, the stepped curing process is as follows: pre-baking at 80-100℃ for 5-10 min → curing at 120-150℃ for 10-20 min → post-curing at 150-170℃ for 5-10 min.

7. A far-infrared radiation coating, characterized in that, The far-infrared radiation coating is prepared by the method described in claim 5 or 6.

8. A far-infrared self-adhesive film, characterized in that, It comprises, in sequence, the far-infrared radiation coating, the substrate, the adhesive layer, and the release layer as described in claim 7.

9. The application of a far-infrared radiation coating as described in any one of claims 1-4, a far-infrared radiation coating as described in claim 7, or a far-infrared self-adhesive film as described in claim 8 in physiotherapy and health products, electric heating products, electric heating products, floor heating products, and greenhouse heating products.

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