Multi-layer composite sunshade film with self-cleaning function and preparation method thereof

Abstract

The invention relates to the technical field of energy-saving building materials, and discloses a multi-layer composite sunshade film with a self-cleaning function, which sequentially comprises a release film layer, a bonding layer, a base material layer I, a spectrum functional layer, a base material layer II and a self-cleaning layer from inside to outside, the raw material of the spectrum functional layer comprises at least one of an infrared absorbent, a visible light absorbent and an ultraviolet absorbent; the self-cleaning layer is a modified layer obtained by modifying the surface of the base material layer II through fluorosilane. According to the sunshade film, the energy-saving performance of a building can be greatly improved, so that the maintenance cost is reduced, and the sunshade film is suitable for being used outdoors for a long time and can also be attached to the outer surface of the building for use.

Description

Technical Field

[0001] The present invention relates to the technical field of energy-saving building materials, in particular to a multi-layer composite sunshade film with a self-cleaning function and a preparation method thereof. Background Art

[0002] Architectural sunshade films are functional films applied to glass curtain walls or windows, primarily for regulating indoor light, providing thermal insulation and energy savings, UV protection, and privacy protection. However, they suffer from several drawbacks: limited spectral regulation efficiency and ineffective shielding of infrared and ultraviolet radiation; easy surface accumulation of dust and stains, affecting optical performance and appearance; and the need for frequent manual cleaning, which is costly and has a limited service life.

[0003] Therefore, there is an urgent need to research and develop a flexible composite sunshade film to solve the above-mentioned problems. Summary of the Invention

[0004] The technical solution adopted in the present invention is:

[0005] First, the present invention provides a multi-layer composite sunshade film with a self-cleaning function, which comprises, from the inside to the outside: a release film layer, an adhesive layer, a first substrate layer, a spectral functional layer, a second substrate layer, and a self-cleaning layer;

[0006] The first substrate layer and the second substrate layer include flexible polyester films;

[0007] The raw material of the spectral functional layer includes at least one of an infrared absorber, a visible light absorber, and an ultraviolet absorber;

[0008] The self-cleaning layer is a modified layer obtained by modifying the surface of the substrate layer 2 with fluorosilane.

[0009] According to some preferred embodiments, the bonding layer is made of highly transparent acrylic adhesive, specifically 3M-8211 transparent pressure-sensitive adhesive or similar optical-grade adhesives.

[0010] According to some preferred embodiments, the material of substrate layer 1 and substrate layer 2 is the same, including at least one of polyethylene terephthalate and polyethylene naphthalate; and / or the bonding layer is made of a highly transparent acrylic adhesive.

[0011] According to some preferred embodiments, the infrared absorber includes at least one of WO3, MoS2, graphene, ITO, ATO, and FTO; the visible light absorber includes at least one of phthalocyanine blue, azo red, CI solvent black 27, Mo, Cr, and Ti; and the ultraviolet absorber includes at least one of TiO2, ZnO, CeO2, ZrO2, benzotriazoles, and benzophenones.

[0012] According to some preferred embodiments, the raw material of the spectral functional layer is TiO2 / ZnO sol, and the mass ratio is 80:20 to 20:80.

[0013] According to some preferred embodiments, the preparation method of TiO2 / ZnO sol is as follows: dissolving butyl titanate and zinc acetate in ethanol respectively; adding deionized water (molar ratio Ti:H2O=1:2) and 0.1 mol / L nitric acid as a hydrolysis catalyst (the added amount is 5-20% molar equivalent of the total molar number of butyl titanate and zinc acetate); ultrasonic stirring for 30 minutes to form a uniform transparent sol; and controlling the solid content of the sol to 2-5wt%, thereby obtaining TiO2 / ZnO sol.

[0014] According to some preferred embodiments, the spectral functional layer can be a composite spectral functional layer obtained by stacking individual sub-spectral functional layers, and the target spectral response is achieved through multi-layer superposition.

[0015] According to some preferred embodiments, the thickness of the release film is preferably 20 to 50 μm, more preferably 30 μm.

[0016] According to some preferred embodiments, the thickness of the adhesive layer is preferably 10 to 40 μm, more preferably 25 μm.

[0017] According to some preferred embodiments, the thickness of the first substrate layer and the second substrate layer ranges from 20 to 60 μm, more preferably 25 μm or 50 μm.

[0018] According to some preferred embodiments, the thickness of the spectral functional layer is 50 to 300 nm, more preferably 150 nm.

[0019] According to some preferred embodiments, the thickness of the self-cleaning layer is 10 to 100 nm, more preferably 30 nm.

[0020] Second, the present invention provides a method for preparing the aforementioned multi-layer composite sunshade film with self-cleaning function, comprising the following steps:

[0021] The surface of the S1 substrate layer 1 is coated with a spectral sol, which is cured to form a spectral functional layer;

[0022] S2 is thermally pressed and laminated with a second substrate layer on the surface of the spectral functional layer;

[0023] S3: Fluorosilane liquid is coated on the surface of the second substrate layer, and after drying, a self-cleaning layer is formed, thereby obtaining a multi-layer composite sunshade film.

[0024] According to some preferred embodiments, in S1, coating is performed by blade coating or roller coating to control the thickness of the spectral functional layer; curing is performed at a temperature of 55 to 70° C. and a time of 45 to 70 seconds, preferably at a temperature of 60° C. and a time of 60 seconds.

[0025] According to some preferred embodiments, in S2, hot pressing is performed at a temperature of 55 to 70°C, a pressure of 0.1 MPa, and a time of 25 to 45 seconds, preferably at a temperature of 60°C, a pressure of 0.1 MPa, and a time of 30 seconds.

[0026] According to some preferred embodiments, in S3, the substrate layer 2 is subjected to plasma activation treatment before coating. Specifically, a radio frequency plasma treatment machine is used to treat the substrate layer 2 at a power of 100 W, an oxygen flow rate of 30 sscm, and a treatment time of 10 s before coating with the fluorosilane solution.

[0027] According to some preferred embodiments, in S3, the fluorosilane liquid is a 1% perfluorooctyltrichlorosilane PFOTS ethanol solution, which is dip-coated for 25 to 40 seconds (preferably 30 seconds), and then dried at 50 to 70°C for 15 to 80 seconds (preferably 60°C, 60 seconds) in an air atmosphere to form a self-cleaning layer.

[0028] According to some preferred embodiments, in S1, glue is applied to the other surface of the substrate layer and a release film layer is attached thereto. The purpose of applying glue is to form an adhesive layer.

[0029] The technical mechanism and beneficial effects adopted by the present invention are:

[0030] (1) The multi-layer composite sunshade film provided by the present invention includes a spectral functional layer, which is used to achieve the purpose of regulating solar radiation penetration through a nano-coating;

[0031] (2) The multi-layer composite sunshade film provided by the present invention includes a self-cleaning layer, which is modified by a low surface energy material to achieve a super-hydrophobic effect, thereby avoiding the appearance of stains; that is, it is chemically modified by fluorosilanes to form a stable super-hydrophobic property, with a contact angle of ≥150° and a rolling angle of ≤5°;

[0032] (3) The multi-layer sunshade film provided by the present invention first undergoes plasma activation treatment on the substrate layer 2, and then undergoes fluorosilane grafting, which first enhances the hydroxyl density and then improves the grafting efficiency, thereby improving the uniformity and durability of the formed self-cleaning layer;

[0033] (4) The multi-layer composite sunshade film provided by the present invention can significantly improve the energy-saving performance of a building, thereby reducing maintenance costs. It is suitable for long-term outdoor use and can also be applied to the exterior surface of a building. DETAILED DESCRIPTION

[0034] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0035] Example 1

[0036] This embodiment provides a multi-layer composite sunshade film, and the preparation method includes the following steps:

[0037] (1) Substrate layer 1 (PET film, 25 μm) was coated with a spectral sol, which was TiO2 / ZnO sol. The film thickness was controlled to be 150 nm, and the spectral functional layer was obtained by thermal curing at 60°C for 60 s. The TiO2 / ZnO sol was prepared by dissolving butyl titanate and zinc acetate (the concentration of butyl titanate and zinc acetate was 0.4 mol / L, and the addition amount was 1:1) in ethanol respectively; deionized water (molar ratio Ti:H2O=1:2) and 0.1 mol / L nitric acid were added as a hydrolysis catalyst (the addition amount of nitric acid accounted for 10% molar equivalent of the total molar number of butyl titanate and zinc acetate); ultrasonic stirring was performed for 30 min to form a uniform transparent sol; the solid content of the sol was controlled to be 2-5 wt%, thus obtaining the TiO2 / ZnO sol.

[0038] (2) The surface of the spectral functional layer is hot-pressed with a second substrate layer (a PET film, 25 μm) at a temperature of 60° C., a pressure of 0.1 MPa, and a time of 30 s.

[0039] (3) The surface of the second substrate layer was activated by oxygen plasma, and then coated with a 1% PFOTS ethanol solution. The layer was then dried in air at 60°C for 60 seconds to obtain a self-cleaning layer with a controlled film thickness of 30 nm. Plasma activation treatment was performed using a radio frequency plasma processor at a power of 100 W, an oxygen flow rate of 30 sscm, and a treatment time of 10 seconds.

[0040] (4) Apply glue to the surface of the substrate layer 1 and adhere the release film layer to form an adhesive layer. Specifically, 3M-8211 transparent pressure-sensitive adhesive is selected, and the film thickness of the adhesive layer is controlled to be 25 μm.

[0041] Comparative Example 1

[0042] The difference between this comparative example and Example 1 is that no spectral functional layer is applied.

[0043] Comparative Example 2

[0044] This comparative example differs from Example 1 in that no self-cleaning layer is applied.

[0045] Comparative Example 3

[0046] The difference between this comparative example and Example 1 is that no oxygen plasma activation treatment is performed.

[0047] Test example

[0048] The multi-layer composite sunshade films prepared in Example 1 and Comparative Examples 1-3 were used as samples for measurement.

[0049] The UV blocking rate, infrared blocking rate, visible light transmittance, water contact angle and rolling angle were measured respectively. The results are shown in Table 1.

[0050] UV blocking rate: measured by ASTM G173-03 / UV-Vis spectrophotometry in the range of 280-400nm;

[0051] Infrared blocking rate: measured by FTIR test or UV-Vis-NIR spectrum integrating sphere measurement in the range of 780-2500nm;

[0052] Visible light transmittance: measured using ASTM D1003 / spectral transmittance integrating sphere method, in the range of 400-780nm;

[0053] Water contact angle: measured using a static contact angle meter (ASTM D7334), averaging 5 points;

[0054] Rolling angle: Measured using the 5μL water drop method, with the platform tilted gradually until it slides.

[0055] Table 1 Measurement results

[0056] index Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 UV blocking rate 99％ 21％ 99％ 99％ Infrared blocking rate 96％ 9％ 96％ 96％ Visible light transmittance 55％ 90％ 55％ 55％ Water contact angle 156° 73° 72° 154° Roll angle 3° 41° 42° 3°

[0057] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A multi-layer composite sunshade film with self-cleaning function, characterized in that: From inside to outside, they are: release film layer, adhesive layer, substrate layer 1, spectral functional layer, substrate layer 2, and self-cleaning layer; The raw material of the spectral functional layer includes at least one of an infrared absorber, a visible light absorber, and an ultraviolet absorber; The self-cleaning layer is a modified layer obtained by modifying the surface of the substrate layer 2 with fluorosilane.

2. The multi-layer composite sunshade film with self-cleaning function according to claim 1, characterized in that: The first substrate layer and the second substrate layer are made of the same material, including at least one of polyethylene terephthalate and polyethylene naphthalate; and / or the adhesive layer is made of a highly transparent acrylic adhesive.

3. The multi-layer composite sunshade film with self-cleaning function according to claim 1, characterized in that: The preferred thickness of the adhesive layer is 10 to 40 μm; and / or the thickness of substrate layer 1 and substrate layer 2 ranges from 20 to 60 μm; and / or the thickness of the spectral functional layer is 50 to 300 nm; and / or the thickness of the self-cleaning layer is 10 to 100 nm.

4. The multi-layer composite sunshade film with self-cleaning function according to any one of claims 1 to 3, characterized in that: The infrared absorber includes at least one of WO3, MoS2, graphene, ITO, ATO, and FTO; the visible light absorber includes at least one of phthalocyanine blue, azo red, CI solvent black 27, Mo, Cr, and Ti; the ultraviolet absorber includes at least one of TiO2, ZnO, CeO2, ZrO2, benzotriazoles, and benzophenones.

5. The multi-layer composite sunshade film with self-cleaning function according to claim 4, characterized in that: The raw material of the spectral functional layer is TiO2 / ZnO sol. The preparation method of TiO2 / ZnO sol is as follows: dissolving butyl titanate and zinc acetate in ethanol respectively; adding deionized water and nitric acid as hydrolysis catalysts; and forming a uniform transparent sol through ultrasonic stirring.

6. A method for preparing a multi-layer composite sunshade film with a self-cleaning function according to any one of claims 1 to 5, characterized in that: The steps include: The surface of the S1 substrate layer 1 is coated with a spectral sol, which is cured to form a spectral functional layer; S2 is thermally pressed and laminated with a second substrate layer on the surface of the spectral functional layer; S3: Fluorosilane liquid is coated on the surface of the substrate layer 2, and a self-cleaning layer is formed after drying, thereby obtaining a multi-layer composite sunshade film.

7. The method for preparing a multi-layer composite sunshade film with a self-cleaning function according to claim 6, characterized in that: In S1, the coating is performed by blade coating or roller coating to control the thickness of the spectral functional layer; the curing temperature is 55 to 70° C. and the curing time is 45 to 70 seconds.

8. The method for preparing a multi-layer composite sunshade film with a self-cleaning function according to claim 6, characterized in that: In S2, hot pressing: temperature 55-70°C, pressure 0.1 MPa, time 25-45 s.

9. The method for preparing a multi-layer composite sunshade film with a self-cleaning function according to claim 6, characterized in that: In S3, the fluorosilane solution is a 1% perfluorooctyltrichlorosilane ethanol solution, which is dipped for 25 to 40 seconds and then dried at 50 to 70° C. in an air atmosphere for 15 to 80 seconds.

10. The method for preparing a multi-layer composite sunshade film with a self-cleaning function according to any one of claims 6 to 9, characterized in that: In S3, plasma activation treatment is performed before coating; a radio frequency plasma treatment machine is used with a power of 100 W, an oxygen flow rate of 30 sscm, and a treatment time of 10 s.