Infrared low-radiation heat-insulation flexible film and preparation method thereof

Abstract

The invention provides an infrared low-radiation heat-insulation flexible film and a preparation method thereof.The preparation method of the infrared low-radiation heat-insulation flexible film comprises the following steps that a first dielectric layer is plated on a flexible transparent polymer film at the normal temperature through the magnetron sputtering technology; and periodically and alternately plating the oxide crystal seed film layer and the metal infrared reflection function film layer, and after the last period is completed, plating the protective film layer on the surface of the metal infrared reflection function film layer. The oxide film layers and the metal infrared reflection function film layers are periodically and alternately plated on the flexible transparent polymer film, and the thermal barrier is arranged on the interface of the metal and the oxide, so that the thermal insulation performance of the film is effectively improved under the condition that the total thickness of the same metal layer is the same. Through experimental tests, the flexible low-radiation heat-insulating film prepared by the invention shows excellent performance in the aspects of visible light transmittance and infrared cut-off rate, the heat transfer coefficient is remarkably reduced, and the flexible low-radiation heat-insulating film can be applied to the aspect of building energy conservation.

Description

Technical Field

[0001] The invention belongs to the technical field of heat reflective films and relates to an infrared low-radiation heat-insulating flexible film and a preparation method thereof. Background Art

[0002] Energy-saving glass, especially Low-E glass, is mainly characterized by its ability to effectively block infrared rays in sunlight and reduce heat transfer. At the same time, it can also maintain a high visible light transmittance to ensure sufficient indoor light and clear vision. This glass significantly reduces the energy consumption of buildings and plays an important role in building energy conservation. It is widely used in windows and curtain walls of buildings such as residences, office buildings, shopping malls, and hospitals. Common Low-E glass relies on a silver layer plated on the surface of the glass to effectively reflect infrared light through optical interference and the electromagnetic properties of the metal. The thickness of the silver film is about 8 to 15 nm (CN222064386U, CN118420241 A, CN211921327U, CN209568008U, CN117819832A, CN105936590A, CN102501447B, CN104264119B, CN104441815B, CN104742446B). In order to improve the infrared cutoff rate, the usual method is to thicken the silver layer, or superimpose a second silver layer and a third silver layer with similar thickness, but the visible light transmittance decreases significantly. Therefore, the common Low-E glass is a single silver layer with a thickness of about 8 to 15 nm. The infrared cutoff rate of the single silver layer Low-E glass is about 60-75% (CN 104742446B, CN 211005131 U, CN205635374U), the visible light transmittance is about 60-90% (CN117819832A, CN116444175A, CN10807330B, CN 102825866 A, CN106746735A, CN102848653B, CN109734332B), and the heat transfer coefficient (K value) is about 1.29 -3.40 W / (m 2 ·K)(CN113149461B, CN108264243B, CN116874199B, CN102848653B). Double silver and triple silver Low-E glass are not often used because of the obvious decrease in visible light transmittance. In order to improve the infrared cutoff rate, current projects often use 2 pieces of 5mm thick single silver Low-E glass and 1 piece of 5mm thick tempered glass to construct 3-glass 2-cavity insulating glass. Although this structure improves the thermal insulation performance, it increases the weight significantly, making it difficult to install, increase the cost and increase the difficulty of maintenance in actual use.

[0003] Low-radiation insulation suspended film hollow glass refers to a hollow glass with two or more cavities formed by separating two pieces of glass and one or more prepared low-radiation insulation films with special spacers. It has the advantages of light weight, low radiation, and good thermal insulation, and has attracted widespread attention in recent years (CN113969729A, CN103498624B). The film structure of the flexible low-radiation insulation film is generally similar to Low-E glass, usually including a first dielectric layer, a seed layer, an infrared reflection function (silver film), a protective layer and a second dielectric layer. However, like Low-E glass, it also encounters a problem, that is, increasing the thickness of the silver film, although it can increase the infrared reflectivity, the visible light transmittance drops significantly to a very low level and cannot meet the demand. Therefore, under the condition of maintaining the same total thickness of the silver layer, how to improve the infrared reflectivity is an urgent problem that needs to be solved at present. Summary of the invention

[0004] In view of this, the present invention proposes a method for preparing an infrared low-radiation heat-insulating film to solve the above problems.

[0005] The technical solution of the present invention is achieved in this way:

[0006] A method for preparing an infrared low-radiation heat-insulating flexible film comprises the following steps: after coating a first dielectric layer on a flexible transparent polymer film at room temperature using magnetron sputtering technology, an oxide seed film layer and a metal infrared reflection functional film layer are alternately coated periodically, and after the last cycle is completed, a protective film layer is coated on the surface of the metal infrared reflection functional film layer.

[0007] Among them, the metal infrared reflection functional film layer is a film layer with a reflection function for infrared light; when the oxide seed film layer is magnetron sputtered with silver on its surface, it promotes the metal crystallization when the metal infrared reflection functional film layer is plated.

[0008] Furthermore, a second dielectric layer is plated on the surface of the protective film layer.

[0009] Furthermore, the flexible transparent polymer film is one or more of polyethylene terephthalate film (PET), polyethylene film (PE), polyurethane film (PU), polypropylene film (PP), and polystyrene film (PS).

[0010] Furthermore, the first dielectric layer and the second dielectric layer are one or more conductive oxide film layers selected from the group consisting of indium oxide, zinc oxide, ITO (indium tin oxide), and FTO (fluorine-doped tin oxide).

[0011] Furthermore, the magnetron sputtering coating of the first dielectric layer and the second dielectric layer is carried out in an atmosphere of a mixed gas of argon and oxygen; the sputtering gas pressure is 0.2-3Pa, and the sputtering power is 50-200W; the film thickness of the first dielectric layer and the second dielectric layer is 2-100nm, and more preferably 10-50nm.

[0012] Furthermore, the oxide seed film layer includes one or more of aluminum oxide, zinc oxide, aluminum-doped zinc oxide (AZO), zirconium oxide, yttrium oxide, magnesium oxide, titanium oxide, beryllium oxide and silicon oxide; the magnetron sputtering coating of the oxide seed film layer is carried out in an argon and oxygen gas atmosphere; the sputtering gas pressure is 0.2-3Pa, and the sputtering power is 50-300W; the film thickness of the oxide seed film layer is 2-10nm, more preferably 2-5nm.

[0013] Furthermore, the metal of the metal infrared reflective functional film layer is one or more of tungsten, silver, chromium, titanium and copper.

[0014] Furthermore, the magnetron sputtering coating of the metal infrared reflection functional film layer is carried out in a pure argon gas atmosphere; the sputtering gas pressure is 0.2-3Pa, and the sputtering power is 50-300W; the single-layer film thickness of the metal infrared reflection functional film layer is 2-20nm, and more preferably 2-5nm.

[0015] Furthermore, the protective film layer is one or more of titanium, titanium dioxide, copper and NiCr, and has a thickness of 2-30 nm, more preferably 2-15 nm.

[0016] An infrared low-radiation heat-insulating flexible film is prepared by any preparation method described in the present invention.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The present invention periodically and alternately plates an oxide film layer and a metal infrared reflective functional film layer on a flexible transparent polymer film, and sets a thermal barrier at the interface between the metal and the oxide. Under the condition of the same total thickness of the same metal layer, the thermal insulation performance of the film is effectively improved while maintaining a relatively good visible light transmittance. The flexible low-emissivity thermal insulation film prepared by the present invention exhibits excellent performance in terms of visible light transmittance and infrared cutoff rate, and the heat transfer coefficient is significantly reduced, providing a new solution for building energy conservation.

[0019] (2) The present invention not only utilizes the electromagnetic properties of metals such as silver to effectively reflect infrared light, but also further improves the thermal insulation performance of the film by periodically alternating the plating of oxide film layers and metal infrared reflection functional film layers while maintaining the same total thickness of the silver layer. The thermal conduction of metals mainly depends on the thermal motion of free electrons, while the thermal conduction of oxides mainly depends on phonons due to the small number of free electrons. By periodically alternating the plating of oxide film layers and metal infrared reflection functional film layers, the heat conduction path is effectively interrupted, which is similar to setting up a thermal barrier. Specifically, phonons are scattered at the material interface, which reduces the mean free path of phonons, thereby significantly reducing the transfer of heat. DETAILED DESCRIPTION

[0020] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention. The experimental methods used in the examples of the present invention are all conventional methods unless otherwise specified.

[0021] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial sources.

[0022] Example

[0023] After the first dielectric layer is deposited on the flexible transparent polymer film at room temperature using magnetron sputtering technology, the oxide seed film layer and the metal infrared reflection functional film layer are alternately deposited periodically. After completing the last cycle, the protective film layer and the second dielectric layer are deposited in sequence on the surface of the metal infrared reflection functional film layer.

[0024] The flexible transparent polymer film includes polyethylene terephthalate film (PET), polyethylene film (PE), polyurethane film (PU), polypropylene film (PP), polystyrene film (PS) and the like.

[0025] The first dielectric layer and the second dielectric layer are oxide films with high transparency and good conductivity such as indium oxide, zinc oxide, ITO, FTO, etc. The magnetron sputtering coating is preferably carried out in an atmosphere of a mixed gas of argon and oxygen; the sputtering pressure is 0.2-3 Pa, and the sputtering power is 50-200 W. The film thickness is controlled by the coating time, and the film thickness is 2-100 nm, more preferably 10-50 nm.

[0026] The oxide seed film layer includes one or more of aluminum oxide, zinc oxide, aluminum-doped zinc oxide (AZO), zirconium oxide, yttrium oxide, magnesium oxide, titanium oxide, beryllium oxide and silicon oxide; when silver is magnetron sputtered on the surface of the oxide seed film layer, the oxide has a promoting effect on the crystallization of silver; the magnetron sputtering coating is preferably carried out in an argon and oxygen atmosphere; the sputtering pressure is 0.2-3Pa, and the sputtering power is 50-300W. The film thickness is controlled by the coating time, and the film thickness is 2-10nm, more preferably 2-5nm.

[0027] The metal of the metal infrared reflective functional film layer includes one or more of tungsten, silver, chromium, titanium and copper, preferably silver.

[0028] The metal infrared reflective functional film layer, the magnetron sputtering coating is preferably carried out in a pure argon gas atmosphere; the sputtering pressure is 0.2-3 Pa, and the sputtering power is 50-300 W. The film thickness is controlled by the coating time, and the thickness of a single layer is 2-20 nm, more preferably 2-5 nm.

[0029] The number of cycles of the oxide seed film layer and the metal infrared reflection functional film layer being alternately plated is 2 or more cycles, preferably 2 to 6 cycles, and the oxide seed film layers in each cycle may be the same or different; the thickness of the metal infrared reflection functional film layer in each cycle may be the same or different;

[0030] The protective film layer is used to prevent the metal layer from being easily oxidized in an oxygen environment and the internal film layer from being easily scratched. It mainly includes titanium, titanium dioxide, copper and NiCr, etc., and has a thickness of 2-30nm, more preferably 2-15nm.

[0031] In addition to the infrared light reflection function of metallic silver, in order to further illustrate the promotion of the thermal insulation performance of the flexible film by alternately plating the oxide seed film layer and the silver film layer, the following examples are plated on a 75 μm thick PET surface, maintaining the total thickness of the silver film at 12 nm. Since it is difficult to controllably plate a high-quality uniform film layer below 2 nm by magnetron sputtering, the thickness of all single layers is not less than 2 nm, but it does not exclude that the film layer with a thickness below 2 nm has the same or better performance.

[0032] In other embodiments, the purpose of the present invention can also be achieved without plating the second dielectric layer.

[0033] The indium oxide target, copper target, silver target, NiCr alloy target, titanium target and zirconium oxide target used in this experiment were purchased from Quanzhou Qijin New Materials Co., Ltd. The AZO target and zinc oxide target used in this experiment were purchased from Beijing Zhongcheng New Materials Technology Co., Ltd.

[0034] The suspended film insulating glass of the present invention is mainly tested for performance by the following method:

[0035] 1. Visible light transmittance and infrared light cutoff

[0036] The visible light transmittance and infrared cutoff rate of the hollow glass in the embodiment were measured using a Lambda 950 spectrophotometer.

[0037] 2.K value

[0038] The K value is measured according to GB 10294-88 and GB / T 2680-94.

[0039] In Examples 1-4, a 75 μm thick PET film was treated with Ar plasma, and the following film layers were sequentially magnetron sputtered on one side to obtain a flexible low-radiation heat-insulating film. In Examples 1-4, 1, 2, 4 and 6 cycles of oxide / metal silver layers were plated respectively. The protective layer of Examples 1-4 was 5 nm thick titanium, the second dielectric layer was 30 nm thick indium oxide, and the metal silver layer was a metal infrared reflection functional film layer.

[0040] Table 1

[0041]

[0042] Table 2

[0043] Example Visible light transmittance / % Infrared cut-off rate / % <![CDATA[Value of K / (W / m 2 ·K)]]> 1 74 70 1.6 2 69 77 1.1 3 62 82 0.8 4 56 85 0.7

[0044] From Table 2, compared with Example 1, Examples 2-4 periodically and alternately plate oxide film layers and metal infrared reflection functional film layers, which significantly improves the infrared cutoff rate, and the visible light transmittance decreases but is still relatively good (can meet the needs), effectively improving the thermal insulation performance of the film.

[0045] In Example 5-7, a 75 μm thick PET film was treated with Ar plasma, and the following film layers were sequentially magnetron sputtered on one side to prepare flexible low-radiation heat-insulating film Examples 5-7. The first and second dielectric layers of Example 5 were indium oxide, the first and second dielectric layers of Example 6 were zinc oxide, and the first and second dielectric layers of Example 7 were ITO.

[0046] Table 3

[0047]

[0048] Table 4

[0049] Example Visible light transmittance / % Infrared cut-off rate / % <![CDATA[Value of K / (W / m 2 ·K)]]> 5 69 77 1.1 6 66 74 1.2 7 68 76 1.1

[0050] The results in Table 4 show that when the dielectric layer is zinc oxide, indium oxide or ITO, the prepared film has good thermal insulation performance and relatively good visible light transmittance.

[0051] In Examples 8-10, a 75 μm thick PET film was treated with Ar plasma, and the following film layers were sequentially magnetron sputtered on one side to obtain flexible low-radiation heat-insulating film Examples 8-10. The oxide seed film layer of Example 8 was AZO, the oxide seed film layer of Example 9 was zinc oxide, and the oxide seed film layer of Example 10 was zirconium oxide. The protective layers of Examples 8-10 were all 5 nm thick titanium, the second dielectric layer was all 30 nm thick indium oxide, and the metal silver layer was a metal infrared reflection functional film layer.

[0052] Table 5

[0053]

[0054] Table 6

[0055] Example Visible light transmittance / % Infrared cut-off rate / % <![CDATA[Value of K / (W / m 2 ·K)]]> 8 69 77 1.1 9 68 76 1.2 10 64 74 1.1

[0056] The results in Table 6 show that when the seed layer is AZO, zinc oxide or zirconium oxide, the prepared film has good thermal insulation performance and relatively good visible light transmittance.

[0057] In Examples 11-13, a 75 μm thick PET film was treated with Ar plasma, and the following film layers were sequentially magnetron sputtered on one side to prepare flexible low-radiation heat-insulating film Examples 11-13. The protective layer of Example 11 was titanium, the protective layer of Example 12 was copper, the protective layer of Example 13 was NiCr alloy, and the metal silver layer was a metal infrared reflection functional film layer.

[0058] Table 7

[0059]

[0060]

[0061] Table 8

[0062] Example Visible light transmittance / % Infrared cut-off rate / % <![CDATA[Value of K / (W / m 2 ·K)]]> 11 69 77 1.1 12 66 78 1.0 13 67 74 1.2

[0063] The results in Table 8 show that the protective layer is titanium, copper or NiCr alloy, and the prepared film has good thermal insulation performance and good visible light transmittance. Examples 11 and 13 are not plated with the second dielectric layer, and also achieve relatively good performance.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an infrared low-radiation heat-insulating flexible film, characterized in that: The following steps are involved: After the first dielectric layer is deposited on the flexible transparent polymer film at room temperature using magnetron sputtering technology, the oxide seed film layer and the metal infrared reflection functional film layer are alternately deposited periodically. After completing the last cycle, a protective film layer is deposited on the surface of the metal infrared reflection functional film layer.

2. The method for preparing the infrared low-radiation heat-insulating flexible film according to claim 1, characterized in that: The flexible transparent polymer film is one or more of polyethylene terephthalate film, polyethylene film, polyurethane film, polypropylene film and polystyrene film.

3. The method for preparing the infrared low-radiation heat-insulating flexible film according to claim 1, characterized in that: The first dielectric layer is one or more conductive oxide film layers selected from the group consisting of indium oxide, zinc oxide, ITO, and FTO.

4. The method for preparing the infrared low-radiation heat-insulating flexible film according to claim 1, characterized in that: The magnetron sputtering coating of the first dielectric layer is carried out in an atmosphere of a mixed gas of argon and oxygen; the sputtering gas pressure is 0.2-3 Pa, and the sputtering power is 50-200 W; the film thickness of the first dielectric layer is 2-100 nm.

5. The method for preparing the infrared low-radiation heat-insulating flexible film according to claim 1, characterized in that: The oxide seed film layer includes one or more of aluminum oxide, zinc oxide, aluminum-doped zinc oxide, zirconium oxide, yttrium oxide, magnesium oxide, titanium oxide, beryllium oxide and silicon oxide; the magnetron sputtering coating of the oxide seed film layer is carried out in an argon and oxygen gas atmosphere; the sputtering gas pressure is 0.2-3Pa, and the sputtering power is 50-300W; the single-layer film thickness of the oxide seed film layer is 2-10nm.

6. The method for preparing the infrared low-radiation heat-insulating flexible film according to claim 1, characterized in that: The metal of the metal infrared reflection functional film layer is one or more of tungsten, silver, chromium, titanium and copper.

7. The method for preparing the infrared low-radiation heat-insulating flexible film according to claim 1, characterized in that: The magnetron sputtering coating of the metal infrared reflection functional film layer is carried out in a pure argon gas atmosphere; the sputtering gas pressure is 0.2-3Pa, and the sputtering power is 50-300W; the single-layer film thickness of the metal infrared reflection functional film layer is 2-20nm.

8. The method for preparing the infrared low-radiation heat-insulating flexible film according to claim 1, characterized in that: The protective film layer is one or more of titanium, titanium dioxide, copper and NiCr, and has a thickness of 2-30 nm.

9. The method for preparing the infrared low-radiation heat-insulating flexible film according to claim 1, characterized in that: A second dielectric layer is plated on the surface of the protective film layer; the second dielectric layer is one or more conductive oxide film layers selected from indium oxide, zinc oxide, ITO, and FTO; the magnetron sputtering coating of the second dielectric layer is carried out in an atmosphere of a mixed gas of argon and oxygen; the sputtering gas pressure is 0.2-3Pa, and the sputtering power is 50-200W; the film thickness of the second dielectric layer is 2-100nm.

10. An infrared low-radiation heat-insulating flexible film, characterized in that: Prepared by the preparation method according to any one of claims 1 to 9.

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