A flexible plating material with a gradient transition layer and a double silver layer structure and a preparation method thereof

Abstract

The application discloses a flexible coating material with a gradient transition layer and a double-silver-layer structure and a preparation method thereof, and comprises a flexible base material layer, a gradient transition layer and a double-silver-layer; the gradient transition layer comprises a bottom coating layer, a middle coating layer and a surface coating layer in sequence; the double-silver-layer comprises a first silver layer, a dielectric layer, a second silver layer and a protective layer in sequence; the middle coating layer contains carboxylated carbon nanotubes; and the carboxylated carbon nanotubes are arranged in a direction. Through the design of the gradient transition layer and the optimization of the double-silver-layer structure, a high-transmittance and high-weather-resistance coating material based on a thermoplastic polyurethane (TPU) base material is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible functional materials, in particular to a high-transmittance and high-weather-resistant coating material based on thermoplastic polyurethane (TPU) substrate, which is particularly suitable for surface functionalization treatment in the fields of automobile protective film and flexible display devices. BACKGROUND

[0002] Traditional flexible coating materials are prone to problems such as poor adhesion, coating cracking, and insufficient light transmittance on TPU substrates. Existing technologies use single-layer silver and pure ZnO dielectric layers, which have the defects of low infrared reflectivity (≤85%) and high resistivity (≥8Ω / sq). For example, the carbon nanotube reinforced layer disclosed in JP2020157994A causes a decrease in light transmittance (<80%) due to uneven dispersion. CN118497692A focuses on the structure of an ultrathin PET substrate + double-silver magnetron layer, which mainly solves the problems of flexibility and heat insulation, but does not address the adhesion of the substrate and the coating. The double-silver layer is directly sputtered on the PET, lacking a transition layer design. Therefore, for TPU substrates, the following problems have not been solved: 1. The metal layer is prone to cracking when stretched or bent, and the barrier performance decays; 2. There is no chemical bonding interface, and the silver layer is prone to oxidation after long-term use; 3. The problem of coating failure caused by the high ductility of TPU substrates has not been solved. SUMMARY

[0003] The present application aims to solve the above technical problems through gradient transition layer design and double-silver layer structure optimization.

[0004] To solve the above technical problems, the present application provides the following technical solutions:

[0005] A flexible coating material with a gradient transition layer and a double-silver layer structure, comprising a flexible substrate layer, a gradient transition layer, and a double-silver layer, which are compounded in a three-layer structure; the gradient transition layer comprises a primer layer, a middle coating layer, and a top coating layer in sequence; the double-silver layer comprises a first silver layer, a dielectric layer, a second silver layer, and a protective layer in sequence; the middle coating layer contains carboxylated carbon nanotubes; the carboxylated carbon nanotubes are arranged in a direction.

[0006] The core innovation of the present application is that through gradient transition layer design combined with double-silver layer optimization, high infrared reflectivity (≥93%) and high light transmittance (≥86%) are maintained while the adhesion, weather resistance, and tensile properties of the coating are significantly improved.

[0007] Preferably, the middle coating layer comprises a mixture of siloxane prepolymer, carboxylated carbon nanotubes, and photoinitiator; the carboxylated carbon nanotubes are arranged in a direction along the stretching direction.

[0008] Preferably, the mass ratio of the siloxane prepolymer, the carboxylated carbon nanotube and the photoinitiator in the middle coating layer is 85-91:8-15:1-5.

[0009] Middle coating layer: composed of siloxane prepolymer (60-80wt%), carboxylated carbon nanotube (5-10wt%) and photoinitiator (1-3wt%), and oriented arrangement to form a conductive network under electric field induction (100-300V / cm).

[0010] Preferably, the primer layer is composed of polyurethane modified acrylate, nano-SiO2 / TiO2 compound particles and silane coupling agent, and the refractive index of the primer layer changes in a gradient manner.

[0011] Preferably, the mass ratio of the polyurethane modified acrylate, the nano-SiO2 / TiO2 compound particles and the silane coupling agent in the primer layer is 70-85:12-25:2-5; in the nano-SiO2 / TiO2 compound particles, the mass ratio of SiO2 to TiO2 changes from 3:1 to 1:2 in a gradient manner, so that the refractive index of the primer layer changes from 1.5 to 1.9 in a gradient manner; and the particle size of the nano-SiO2 / TiO2 compound particles is 20-50nm.

[0012] Primer layer: composed of polyurethane modified acrylate (70-85wt%), nano-SiO2 / TiO2 compound particles (12-25wt%, particle size 20-50nm) and silane coupling agent (2-5wt%), and the modulus after curing is 50-100MPa; by adjusting the mixing ratio of SiO2 (n=1.46) to TiO2 (n=2.4) (3:1→1:2), the refractive index is continuously changed from 1.5 (matching TPU) to 1.9 (matching Al2O3 top coating layer).

[0013] Preferably, the flexible substrate layer comprises a TPU substrate; the top coating layer comprises an Al2O3 nanocrystalline layer; the first silver layer comprises an Ag target material sputtering layer; the dielectric layer comprises a ZnO:Ga dielectric layer; the second silver layer comprises an Ag target material sputtering layer; and the protective layer comprises a Si3N4 protective layer.

[0014] Top coating layer: Al2O3 nanocrystalline layer (thickness 20-50nm) synthesized by sol-gel method, forming Al-O-Ag chemical bond with silver layer, and the surface hydroxyl density is ≥5 / nm 2 .

[0015] The scheme is a customized solution specially for the characteristics of the TPU substrate, and there is an essential difference from the PET substrate scheme. For example, the TPU modulus (10-50 MPa) needs a primer layer modulus of 50-100 MPa to achieve stress buffering; the PET modulus (2-4 GPa) can be directly sputtered without stress buffering; the core of the application lies in a scheme for plating on TPU, and the stretching performance is also considered to a certain extent, so as to ensure that the plated layer will not crack within a certain stretching range (PET plating, the stretching cracking rate of the plated layer is extremely low).

[0016] Preferably, the thickness of the flexible substrate layer includes 50-150 μm; the thickness of the primer layer includes 1.0-1.5 μm; the thickness of the intermediate coating layer includes 0.5-1.0 μm; the thickness of the top coating layer includes 20-50 nm; the thickness of the first silver layer includes 10-15 nm; the thickness of the medium layer includes 5-8 nm; the thickness of the second silver layer includes 10-15 nm; the thickness of the protective layer includes 20-30 nm; in the Al2O3 nanocrystalline layer, the surface hydroxyl density is ≥5 / nm 2 ; in the ZnO:Ga medium layer, the doping concentration of Ga includes 2-5 wt %.

[0017] A preparation method of the flexible plating material with the gradient transition layer and the double silver layer structure, characterized in that it comprises the following steps:

[0018] A, pretreatment of the flexible substrate layer;

[0019] B, coating the primer layer on the flexible substrate layer and heating and curing;

[0020] C, coating the intermediate coating layer on the primer layer, and after electric field orientation induction, UV curing;

[0021] D, spin coating Al2O3 nanocrystalline sol on the intermediate coating layer; forming the top coating layer by sol-gel method, and sintering and curing;

[0022] E, magnetron sputtering the first silver layer on the top coating layer;

[0023] F, magnetron sputtering the medium layer on the first silver layer;

[0024] G, magnetron sputtering the second silver layer on the medium layer;

[0025] H, magnetron sputtering the protective layer on the second silver layer to obtain the flexible plating material with the gradient transition layer and the double silver layer structure.

[0026] Preferably, in step A, the pre-treatment comprises plasma cleaning; in step B, the conditions for heat curing comprise: a curing temperature of 80-100 DEG C, a curing time of 2-30 min, and a modulus of 50-100 MPa after curing; in step C, the conditions for UV curing comprise: a light wavelength of 365 nm, and a light energy of 500-1200 mJ / cm 2 ; in step D, the conditions for sintering curing comprise: a sintering temperature of 120 DEG C, and a sintering time of 5-30 min; in step E, the conditions for magnetron sputtering comprise: a sputtering power of 1-2 kw, a sputtering atmosphere of 0.6 Pa Ar, a sputtering temperature of 60-80 DEG C, and a speed of 1-2 m / min; in step F, the conditions for magnetron sputtering comprise: a sputtering power of 30-50 kw, a sputtering atmosphere of O2 and Ar mixed at a volume ratio of 1:9, a sputtering temperature of 60-80 DEG C, and a speed of 2 m / min; in step G, the conditions for magnetron sputtering comprise: a sputtering power of 1-2 kw, a sputtering atmosphere of 0.6 Pa Ar, a sputtering temperature of 80 DEG C, and a speed of 2 m / min; in step H, the conditions for magnetron sputtering comprise: a sputtering power of 0.5 kw, a sputtering atmosphere of 0.6 Pa Ar, a sputtering temperature of 60-80 DEG C, and a speed of 2 m / min.

[0027] Preferably, in step A, the conditions for plasma cleaning comprise: an Ar atmosphere, a cleaning power of 0.2 kw, and a cleaning time of 2 min; in step B, the continuous gradient transition of refractive index is achieved by a micro-gravure coater step-by-step coating method, and the specific operation comprises: adding the nano SiO2 / TiO2 compound particles in three batches, the mass ratio of SiO2 to TiO2 in the first batch of nano SiO2 / TiO2 compound particles is 3:1, pre-curing at 80 DEG C for 1 min after coating, the mass ratio of SiO2 to TiO2 in the second batch of nano SiO2 / TiO2 compound particles is 2:1, pre-curing at 80 DEG C for 1 min after coating, and the mass ratio of SiO2 to TiO2 in the first batch of nano SiO2 / TiO2 compound particles is 1:2, pre-curing at 80 DEG C for 1 min after coating; in step C, the conditions for electric field orientation induction comprise: an electric field intensity of 100-300 V / cm, and an action time of 30-60 s; in step D, the solid content of the Al2O3 nano-crystal sol comprises 5 wt%, and the hydroxyl density is ≥5 / nm 2 ; in step E, the roughness of the first silver layer is <5 nm; in step F, the resistivity of the dielectric layer is ≤1x10 -3 Ω·cm; in step G, the roughness of the second silver layer is <5 nm; and in step G, the hardness of the protective layer is ≥1800 HV.

[0028] The present application has the following beneficial effects:

[0029] The flexible plated material obtained by the present application has the following properties:

[0030] 1. Visible light transmittance ≥ 86%, infrared reflectance ≥ 93%, square resistance ≤ 4.2 Ω / sq;

[0031] 2. Crack density ≤ 0.05 strips / mm after stretching 300% 2 , salt spray resistance 1000h without corrosion;

[0032] 3. Compatible with roll-to-roll mass production, film thickness uniformity deviation ≤ ± 5%. DETAILED DESCRIPTION

[0033] In the following examples and comparative examples, unless otherwise specified, the siloxane prepolymer is selected from Wacker SILIKOPHEN P80 / X; the carboxylated carbon nanotube is selected from TNIM8 of Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences; and the polyurethane modified acrylate is selected from Covestro Desmolux U100. The specific selection of the above raw materials is only for experimental selection, and other similar raw materials of other companies can be equally replaced.

[0034] Example 1

[0035] 1. Substrate pretreatment

[0036] TPU substrate (thickness 150 μm) was subjected to plasma cleaning (Ar atmosphere, 0.2 kW, 2 min);

[0037] 2. Gradient transition layer preparation

[0038] (1) Bottom coating

[0039] Raw materials: polyurethane modified acrylate (Covestro Desmolux U100, 85wt%), nano-SiO2 / TiO2 compound particles (13wt%, SiO2:TiO2 mass ratio gradient changes, particle size 20~50 nm), silane coupling agent KH-550 (2wt%);

[0040] Gradient refractive index implementation process (step-by-step coating method):

[0041] First layer: SiO2:TiO2=3:1 → refractive index 1.5 (matching TPU substrate);

[0042] Second layer: SiO2:TiO2=1:1 → refractive index 1.7;

[0043] Third layer: SiO2:TiO2=1:2 → refractive index 1.9 (matching Al2O3 surface layer);

[0044] Coating: three-step gradient coating with micro-gravure coater, total thickness 1.2 μm;

[0045] Curing: 80°C / 10min, modulus 80MPa;

[0046] (2) Middle coating preparation

[0047] Raw materials: siloxane prepolymer (Wacker SILIKOPHEN P80 / X, 80wt%), carboxylated carbon nanotube (CAS TNIM8, 15wt%), photoinitiator TPO (5wt%);

[0048] Coating: slot coating, thickness 1.0μm;

[0049] Orientation: electric field induction (200V / cm, 45s) to orient carbon tubes along the stretching direction;

[0050] Curing: UV light (365nm, 500mJ / cm 2 );

[0051] (3) Top coating preparation

[0052] Spin coating Al2O3 nanocrystal sol (5wt% solid content, hydroxyl density≥5 / nm 2 );

[0053] Sintering: 120°C / 5min, thickness 30nm;

[0054] 3. Double silver layer magnetron sputtering

[0055] First silver layer: Ag target, sputtering power 1.0kW, Ar atmosphere 0.6Pa, temperature 80°C, speed 2m / min;

[0056] ZnO:Ga dielectric layer: Ga doping 5wt%, power 40kW, Ar:O2=8:2, temperature 100°C, speed 2m / min;

[0057] Second silver layer: Ag target, sputtering power 1.5kW, Ar atmosphere 0.6Pa, temperature 80°C, speed 2m / min;

[0058] Si3N4 protective layer: 0.5kW, Ar atmosphere 0.6Pa, temperature 70°C, speed 2m / min.

[0059] Example 2

[0060] 1. Substrate pretreatment

[0061] TPU substrate (thickness 150μm) was cleaned by plasma (Ar atmosphere, 0.2kW, 2min);

[0062] 2. Gradient transition layer preparation

[0063] (1) Primer coating

[0064] Raw materials: polyurethane modified acrylate (Cognis Desmolux U100, 70 wt%), nano-SiO2 / TiO2 compound particles (25 wt%, SiO2:TiO2 mass ratio gradient change, particle size 20-50 nm), silane coupling agent KH-550 (5 wt%);

[0065] Gradient refractive index implementation process (step-by-step coating method):

[0066] First layer: SiO2:TiO2=3:1 → refractive index 1.5 (match TPU substrate);

[0067] Second layer: SiO2:TiO2=1:1 → refractive index 1.7;

[0068] Third layer: SiO2:TiO2=1:2 → refractive index 1.9 (match Al2O3 surface layer);

[0069] Coating: three-step gradient coating with micro-gravure coater, total thickness 1.5 μm;

[0070] Curing: 100°C / 2 min, modulus 100 MPa;

[0071] (2) Middle coating

[0072] Raw materials: siloxane prepolymer (Wingtech SILIKOPHEN P80 / X, 88 wt%), carboxylated carbon nanotube (Chinese Academy of Sciences TNIM8, 10 wt%), photoinitiator TPO (2 wt%);

[0073] Coating: slot coating, thickness 1.0 μm;

[0074] Directional arrangement: electric field induction (200 V / cm, 45 s) to make carbon tubes directional along the stretching direction;

[0075] Curing: UV light (365 nm, 1200 mJ / cm 2 );

[0076] (3) Surface coating preparation

[0077] Spin coating Al2O3 nanocrystal sol (5 wt% solid content, hydroxyl density ≥5 / nm 2 );

[0078] Sintering: 120°C / 30 min, thickness 30 nm;

[0079] 3, Double silver layer magnetron sputtering

[0080] First silver layer: Ag target, sputtering power 2.0 kW, Ar atmosphere 0.6 Pa, temperature 60 °C, machine speed 1 m / min;

[0081] ZnO:Ga intermediate layer: Ga doping 5 wt%, power 50 kW, Ar:O2=8:2, temperature 80 °C, machine speed 2 m / min;

[0082] Second silver layer: Ag target, sputtering power 2.0 kW, Ar atmosphere 0.6 Pa, temperature 60 °C, machine speed 2 m / min;

[0083] Si3N4 protective layer: 0.5 kW, Ar atmosphere 0.6 Pa, temperature 60 °C, machine speed 2 m / min.

[0084] Example 3

[0085] 1. Substrate pretreatment

[0086] TPU substrate (thickness 50 pm) was subjected to plasma cleaning (Ar atmosphere, 0.2 kW, 2 min);

[0087] 2. Gradient transition layer preparation

[0088] (1) Primer coating

[0089] Raw materials: polyurethane-modified acrylate (Covestro Desmolux U100, 83 wt%), nano-SiO2 / TiO2 compound particles (12 wt%, SiO2:TiO2 mass ratio gradient change, particle size 20-50 nm), silane coupling agent KH-550 (5 wt%);

[0090] Gradient refractive index implementation process (step-by-step coating method):

[0091] First layer: SiO2:TiO2=3:1 → refractive index 1.5 (matching TPU substrate);

[0092] Second layer: SiO2:TiO2=1:1 → refractive index 1.7;

[0093] Third layer: SiO2:TiO2=1:2 → refractive index 1.9 (matching Al2O3 surface layer);

[0094] Coating: three-step gradient coating with micro-gravure coater, total thickness 1.0 pm;

[0095] Curing: 80 °C / 30 min, modulus 50 MPa;

[0096] (2) Middle coating

[0097] Raw materials: siloxane prepolymer (Wacker SILIKOPHEN P80 / X, 91 wt%), carboxylated carbon nanotube (CAS TNIM8, 8 wt%), photoinitiator TPO (1 wt%);

[0098] Coating: slot-die coating, thickness 0.5 μm;

[0099] Oriented arrangement: electric field induced (200 V / cm, 45 s) to make carbon tubes oriented along the stretching direction;

[0100] Curing: UV light (365 nm, 500 mJ / cm 2 );

[0101] (3) Surface coating preparation

[0102] Spin-coating Al2O3 nanocrystal sol (5 wt% solid content, hydroxyl density ≥ 5 / nm 2 );

[0103] Sintering: 120 °C / 5 min, thickness 30 nm;

[0104] 3. Double silver layer magnetron sputtering

[0105] First silver layer: Ag target, sputtering power 1.0 kW, Ar atmosphere 0.6 Pa, temperature 80 °C, machine speed 2 m / min;

[0106] ZnO: Ga dielectric layer: Ga doping 2 wt%, power 30 kW, Ar:O2=8:2, temperature 100 °C, machine speed 2 m / min;

[0107] Second silver layer: Ag target, sputtering power 1.0 kW, Ar atmosphere 0.6 Pa, temperature 80 °C, machine speed 2 m / min;

[0108] Si3N4 protective layer: 0.5 kW, Ar atmosphere 0.6 Pa, temperature 80 °C, machine speed 2 m / min.

[0109] Comparative Example 1

[0110] 1. Substrate pretreatment

[0111] TPU substrate (thickness 150 μm) was subjected to plasma cleaning (Ar atmosphere, 0.2 kW, 2 min);

[0112] 2. Gradient transition layer preparation

[0113] (1) Middle coating coating

[0114] Raw materials: siloxane prepolymer (Wacker SILIKOPHEN P80 / X, 80 wt%), carboxylated carbon nanotube (CAS TNIM8, 15 wt%), photoinitiator TPO (5 wt%);

[0115] Coating: slot-die coating, thickness 1.0 μm;

[0116] Oriented arrangement: electric field induced (200 V / cm, 45 s) to make carbon tubes oriented along the stretching direction;

[0117] Curing: UV light (365 nm, 500 mJ / cm 2 );

[0118] (2) Surface coating preparation

[0119] Spin-coating Al2O3 nanocrystal sol (5 wt% solid content, hydroxyl density ≥ 5 / nm 2 );

[0120] Sintering: 120 °C / 5 min, thickness 30 nm;

[0121] 3. Double silver layer magnetron sputtering

[0122] First silver layer: Ag target, sputtering power 1.0 kW, Ar atmosphere 0.6 Pa, temperature 80 °C, machine speed 2 m / min;

[0123] ZnO: Ga dielectric layer: Ga doping 5 wt%, power 40 kW, Ar:O2=8:2, temperature 100 °C, machine speed 2 m / min;

[0124] Second silver layer: Ag target, sputtering power 1.5 kW, Ar atmosphere 0.6 Pa, temperature 80 °C, machine speed 2 m / min;

[0125] Si3N4 protective layer: 0.5 kW, Ar atmosphere 0.6 Pa, temperature 70 °C, machine speed 2 m / min.

[0126] Comparative Example 2

[0127] 1. Substrate pretreatment

[0128] TPU substrate (thickness 150 μm) was subjected to plasma cleaning (Ar atmosphere, 0.2 kW, 2 min);

[0129] 2. Gradient transition layer preparation

[0130] (1) Bottom coating

[0131] Raw materials: polyurethane modified acrylate (Cognis Desmolux U100, 85wt%), nano-SiO2 / TiO2 compound particles (13wt%, SiO2:TiO2 mass ratio gradient change, particle size 20~50nm), silane coupling agent KH-550 (2wt%);

[0132] Gradient refractive index implementation process (step-by-step coating method):

[0133] First layer: SiO2:TiO2=3:1 → refractive index 1.5 (match TPU substrate);

[0134] Second layer: SiO2:TiO2=1:1 → refractive index 1.7;

[0135] Third layer: SiO2:TiO2=1:2 → refractive index 1.9 (match Al2O3 surface layer);

[0136] Coating: three-step gradient coating with micro-gravure coater, total thickness 1.2μm;

[0137] Curing: 80℃ / 10min, modulus 80MPa;

[0138] (2) Middle coating coating

[0139] Raw materials: siloxane prepolymer (Wingtech SILIKOPHEN P80 / X, 80wt%), carboxylated carbon nanotube (Chinese Academy of Sciences TNIM8, 15wt%), photoinitiator TPO (5wt%);

[0140] Coating: slot coating, thickness 1.0μm;

[0141] Curing: UV light (365nm, 500mJ / cm 2 );

[0142] (3) Surface coating preparation

[0143] Spin coating Al2O3 nanocrystalline sol (5wt% solid content, hydroxyl density ≥5 / nm 2 );

[0144] Sintering: 120℃ / 5min, thickness 30nm;

[0145] 3, Double silver layer magnetron sputtering

[0146] First silver layer: Ag target, sputtering power 1.0kW, Ar atmosphere 0.6Pa, temperature 80℃, machine speed 2m / min;

[0147] ZnO:Ga medium layer: Ga doped 5wt%, power 40kW, Ar:O2=8:2, temperature 100℃, machine speed 2m / min;

[0148] Second silver layer: Ag target, sputtering power 1.5kW, Ar atmosphere 0.6Pa, temperature 80℃, machine speed 2m / min;

[0149] Si3N4 protective layer: 0.5kW, Ar atmosphere 0.6Pa, temperature 70℃, machine speed 2m / min.

[0150] Comparative Example 3

[0151] 1. Substrate pretreatment

[0152] TPU substrate (thickness 150μm) was subjected to plasma cleaning (Ar atmosphere, 0.2kW, 2min);

[0153] 2. Gradient transition layer preparation

[0154] (1) Primer coating

[0155] Raw materials: polyurethane modified acrylate (Covestro Desmolux U100, 85wt%), nano-SiO2 / TiO2 compound particles (13wt%, SiO2:TiO2 mass ratio gradient changes, particle size 20~50nm), silane coupling agent KH-550 (2wt%);

[0156] Gradient refractive index implementation process (step-by-step coating method):

[0157] First layer: SiO2:TiO2=3:1 → refractive index 1.5 (matching TPU substrate);

[0158] Second layer: SiO2:TiO2=1:1 → refractive index 1.7;

[0159] Third layer: SiO2:TiO2=1:2 → refractive index 1.9 (matching Al2O3 surface layer);

[0160] Coating: three-step gradient coating with micro-gravure coater, total thickness 1.2μm;

[0161] Curing: 80℃ / 10min, modulus 80MPa;

[0162] (2) Middle coating

[0163] Raw materials: siloxane prepolymer (Wacker SILIKOPHEN P80 / X, 80wt%), carboxylated carbon nanotubes (Chinese Academy of Sciences TNIM8, 15wt%), photoinitiator TPO (5wt%);

[0164] Coating: slot-die coating, thickness 1.0 μm;

[0165] Orientation: carbon tubes oriented along the stretching direction by electric field induction (200 V / cm, 45 s);

[0166] Curing: UV light (365 nm, 500 mJ / cm 2 );

[0167] (3) Topcoat preparation

[0168] Spin-coating Al2O3 nanocrystal sol (5 wt% solid content, hydroxyl density <3 / nm 2 );

[0169] Sintering: 120 °C / 5 min, thickness 30 nm;

[0170] 3. Double silver layer magnetron sputtering

[0171] First silver layer: Ag target, sputtering power 1.0 kW, Ar atmosphere 0.6 Pa, temperature 80 °C, machine speed 2 m / min;

[0172] ZnO:Ga dielectric layer: Ga doping 5 wt%, power 40 kW, Ar:O2=8:2, temperature 100 °C, machine speed 2 m / min;

[0173] Second silver layer: Ag target, sputtering power 1.5 kW, Ar atmosphere 0.6 Pa, temperature 80 °C, machine speed 2 m / min;

[0174] Si3N4 protective layer: 0.5 kW, Ar atmosphere 0.6 Pa, temperature 70 °C, machine speed 2 m / min.

[0175] Comparative Example 4

[0176] 1. Substrate pretreatment

[0177] TPU substrate (thickness 150 μm) was subjected to plasma cleaning (Ar atmosphere, 0.2 kW, 2 min);

[0178] 2. Gradient transition layer preparation

[0179] (1) Primer coating

[0180] Raw materials: polyurethane-modified acrylate (Covestro Desmolux U100, 85 wt%), nano-SiO2 / TiO2 compound particles (13 wt%, SiO2:TiO2 mass ratio gradient varies, particle size 20-50 nm), silane coupling agent KH-550 (2 wt%);

[0181] Gradient refractive index implementation process (step-by-step coating method):

[0182] First layer: SiO2:TiO2=3:1 → refractive index 1.5 (match TPU substrate);

[0183] Second layer: SiO2:TiO2=1:1 → refractive index 1.7;

[0184] Third layer: SiO2:TiO2=1:2 → refractive index 1.9 (match Al2O3 top layer);

[0185] Coating: Micro gravure coater three-step gradient coating, total thickness 1.2 pm;

[0186] Curing: 80°C / 10 min, modulus 80 MPa;

[0187] (2) Middle coating layer coating

[0188] Raw materials: siloxane prepolymer (Yingchuang SILIKOPHEN P80 / X, 80 wt%), carboxylated carbon nanotube (Chinese Academy of Sciences TNIM8, 15 wt%), photoinitiator TPO (5 wt%);

[0189] Coating: slot coating, thickness 1.0 pm;

[0190] Directional arrangement: electric field induction (200 V / cm, 45 s) to make carbon tubes directional along the stretching direction;

[0191] Curing: UV light (365 nm, 500 mJ / cm 2 );

[0192] (3) Surface coating layer preparation

[0193] Spin coating Al2O3 nanocrystal sol (5 wt% solid content, hydroxyl density <3 / nm 2 );

[0194] Sintering: 120°C / 5 min, thickness 30 nm;

[0195] 3. Silver layer magnetron sputtering

[0196] Silver layer: Ag target, sputtering power 1.0 kW, Ar atmosphere 0.6 Pa, temperature 80°C, speed 2 m / min;

[0197] ZnO:Ga dielectric layer: Ga doping 5 wt%, power 40 kW, Ar:O2=8:2, temperature 100°C, speed 2 m / min;

[0198] Si3N4 protective layer: 0.5 kW, Ar atmosphere 0.6 Pa, temperature 70°C, speed 2 m / min.

[0199] Comparative Example 5

[0200] 1. Substrate pretreatment

[0201] TPU substrate (thickness 150 pm) was plasma cleaned (Ar atmosphere, 0.2 kW, 2 min);

[0202] 2. Gradient transition layer preparation

[0203] (1) Primer coating

[0204] Raw materials: polyurethane-modified acrylate (Covestro Desmolux U100, 85 wt%), nano-SiO2 / TiO2 compound particles (13 wt%, SiO2:TiO2 mass ratio gradient changes, particle size 20-50 nm), silane coupling agent KH-550 (2 wt%);

[0205] Gradient refractive index implementation process (step-by-step coating method):

[0206] First layer: SiO2:TiO2=3:1 → refractive index 1.5 (matching TPU substrate);

[0207] Second layer: SiO2:TiO2=1:1 → refractive index 1.7;

[0208] Third layer: SiO2:TiO2=1:2 → refractive index 1.9 (matching Al2O3 surface layer);

[0209] Coating: three-step gradient coating with micro-gravure coater, total thickness 1.2 pm;

[0210] Curing: 80°C / 10 min, modulus 80 MPa;

[0211] (2) Middle coating

[0212] Raw materials: siloxane prepolymer (Wacker SILIKOPHEN P80 / X, 80 wt%), carboxylated carbon nanotubes (Chinese Academy of Sciences TNIM8, 15 wt%), photoinitiator TPO (5 wt%);

[0213] Coating: slot coating, thickness 1.0 pm;

[0214] Directional arrangement: electric field induction (200 V / cm, 45 s) to make carbon tubes directional along the stretching direction;

[0215] Curing: UV light (365 nm, 500 mJ / cm 2 );

[0216] (3) Surface coating preparation

[0217] Spin-coating Al2O3 nanocrystal sol (5wt% solid content, hydroxyl density ≥5 per nm 2 );

[0218] Sintering: 120°C / 5min, thickness 30nm;

[0219] 3. Silver layer magnetron sputtering

[0220] Silver layer: Ag target, sputtering power 1.0kW, Ar atmosphere 0.6Pa, temperature 80°C, machine speed 2m / min;

[0221] Si3N4 protective layer: 0.5kW, Ar atmosphere 0.6Pa, temperature 70°C, machine speed 2m / min.

[0222] Comparative Example 6

[0223] 1. Substrate pretreatment

[0224] TPU substrate (thickness 150μm) was subjected to plasma cleaning (Ar atmosphere, 0.2kW, 2min);

[0225] 2. Gradient transition layer preparation

[0226] (1) Primer coating

[0227] Raw materials: polyurethane-modified acrylate (Covestro Desmolux U100, 85wt%), nano-SiO2 / TiO2 compound particles (13wt%, SiO2:TiO2 mass ratio gradient changes, particle size 20~50nm), silane coupling agent KH-550 (2wt%);

[0228] Gradient refractive index implementation process (step-by-step coating method):

[0229] First layer: SiO2:TiO2=3:1 → refractive index 1.5 (matching TPU substrate);

[0230] Second layer: SiO2:TiO2=1:1 → refractive index 1.7;

[0231] Third layer: SiO2:TiO2=1:2 → refractive index 1.9 (matching Al2O3 surface layer);

[0232] Coating: three-step gradient coating with micro-gravure coater, total thickness 1.2μm;

[0233] Curing: 80°C / 10min, modulus 80MPa;

[0234] (2) Middle coating

[0235] Raw materials: siloxane prepolymer (Wacker SILIKOPHEN P80 / X, 80 wt%), carboxylated carbon nanotube (CAS TNIM8, 15 wt%), photoinitiator TPO (5 wt%);

[0236] Coating: slot-die coating, thickness 1.0 μm;

[0237] Oriented arrangement: electric field induction (200 V / cm, 45 s) to make carbon tubes oriented along the stretching direction;

[0238] Curing: UV light (365 nm, 500 mJ / cm 2 );

[0239] (3) Surface coating preparation

[0240] Spin coating Al2O3 nanocrystal sol (5 wt% solid content, hydroxyl density ≥ 5 / nm 2 );

[0241] Sintering: 120 °C / 5 min, thickness 30 nm;

[0242] 3. Double silver layer magnetron sputtering

[0243] First silver layer: Ag target, sputtering power 1.0 kW, Ar atmosphere 0.6 Pa, temperature 80 °C, machine speed 2 m / min;

[0244] ZnO: Ga dielectric layer: Ga doping 5 wt%, power 40 kW, Ar:O2=8:2, temperature 100 °C, machine speed 2 m / min;

[0245] Second silver layer: Ag target, sputtering power 1.5 kW, Ar atmosphere 0.6 Pa, temperature 80 °C, machine speed 2 m / min.

[0246] Comparative Example 7

[0247] 1. Substrate pretreatment

[0248] TPU substrate (thickness 150 μm) was subjected to plasma cleaning (Ar atmosphere, 0.2 kW, 2 min);

[0249] 2. Gradient transition layer preparation

[0250] (1) Bottom coating

[0251] Raw materials: polyurethane modified acrylate (Covestro Desmolux U100, 85 wt%), nano-SiO2 / TiO2 compound particles (13 wt%, SiO2:TiO2 mass ratio gradient changes, particle size 20~50 nm), silane coupling agent KH-550 (2 wt%);

[0252] Gradient refractive index implementation process (step-by-step coating method):

[0253] First layer: SiO2:TiO2=3:1 → refractive index 1.5 (match TPU substrate);

[0254] Second layer: SiO2:TiO2=1:1 → refractive index 1.7;

[0255] Third layer: SiO2:TiO2=1:2 → refractive index 1.9 (match Al2O3 surface layer);

[0256] Coating: micro gravure coater three-step gradient coating, total thickness 1.2 μm;

[0257] Curing: 80°C / 10 min, modulus 80 MPa;

[0258] (2) Middle coating layer coating

[0259] Raw materials: siloxane prepolymer (Yingchuang SILIKOPHEN P80 / X, 80 wt%), carboxylated carbon nanotubes (Chinese Academy of Sciences TNIM8, 15 wt%), photoinitiator TPO (5 wt%);

[0260] Coating: slot coating, thickness 1.0 μm;

[0261] Directional arrangement: electric field induction (200 V / cm, 45 s) to make carbon tubes directional along the stretching direction;

[0262] Curing: UV light (365 nm, 500 mJ / cm 2 );

[0263] (3) Surface coating layer preparation

[0264] Spin coating Al2O3 nanocrystal sol (5 wt% solid content, hydroxyl density ≥ 5 / nm 2 );

[0265] Sintering: 120°C / 5 min, thickness 30 nm;

[0266] 3, Double silver layer magnetron sputtering

[0267] First silver layer: Ag target, sputtering power 1.0 kW, Ar atmosphere 0.6 Pa, temperature 80°C, speed 2 m / min;

[0268] ZnO dielectric layer: power 40 kW, Ar:O2=8:2, temperature 100°C, speed 2 m / min;

[0269] Second silver layer: Ag target, sputtering power 1.5 kW, Ar atmosphere 0.6 Pa, temperature 80°C, speed 2 m / min;

[0270] Si3N4 protective layer: 0.5 kW, Ar atmosphere 0.6 Pa, temperature 70 °C, machine speed 2 m / min.

[0271] Comparative Example 8

[0272] 1. Substrate pretreatment

[0273] TPU substrate (thickness 150 pm) was subjected to plasma cleaning (Ar atmosphere, 0.2 kW, 2 min);

[0274] 2. Gradient transition layer preparation

[0275] (1) Primer coating

[0276] Raw materials: polyurethane-modified acrylate (Covestro Desmolux U100, 85 wt%), nano-SiO2 / TiO2 compound particles (13 wt%, SiO2:TiO2 mass ratio gradient change, particle size 20-50 nm), silane coupling agent KH-550 (2 wt%);

[0277] Refractive index realization process (step-by-step coating method):

[0278] First layer: SiO2:TiO2=3:1 → refractive index 1.7;

[0279] Second layer: SiO2:TiO2=3:1 → refractive index 1.7;

[0280] Third layer: SiO2:TiO2=3:1 → refractive index 1.7;

[0281] Coating: micro-gravure coater three-step gradient coating, total thickness 1.2 pm;

[0282] Curing: 80 °C / 10 min, modulus 80 MPa;

[0283] (2) Middle coating

[0284] Raw materials: siloxane prepolymer (Wacker SILIKOPHEN P80 / X, 80 wt%), carboxylated carbon nanotubes (Chinese Academy of Sciences TNIM8, 15 wt%), photoinitiator TPO (5 wt%);

[0285] Coating: slot coating, thickness 1.0 pm;

[0286] Directional arrangement: electric field induction (200 V / cm, 45 s) to make carbon tubes directional along the stretching direction;

[0287] Curing: UV light (365 nm, 500 mJ / cm 2 );

[0288] (3) Face coating preparation

[0289] Spin coating Al2O3 nanocrystal sol (5wt% solid content, hydroxyl density≥5 / nm 2 );

[0290] Sintering: 120°C / 5min, thickness 30nm;

[0291] 3. Double silver layer magnetron sputtering

[0292] First silver layer: Ag target, sputtering power 1.0kW, Ar atmosphere 0.6Pa, temperature 80°C, machine speed 2m / min;

[0293] ZnO:Ga dielectric layer: Ga doping 5wt%, power 40kW, Ar:O2=8:2, temperature 100°C, machine speed 2m / min;

[0294] Second silver layer: Ag target, sputtering power 1.5kW, Ar atmosphere 0.6Pa, temperature 80°C, machine speed 2m / min;

[0295] Si3N4 protective layer: 0.5kW, Ar atmosphere 0.6Pa, temperature 70°C, machine speed 2m / min.

[0296] Example 1

[0297] The performance of Example 1 and prior art (commercial TPU double silver plated film product, taking the Coolde gold-plated thermal curtain product as an example) was tested, and the test design is shown in Table 1:

[0298] Table 1

[0299]

[0300] From the test results, it can be seen that the visible light transmittance of the present application is 88.3%, which is increased by 21.8% compared with the commercial TPU double silver plated film product; the infrared reflectivity is 93.7%, which is increased by 43.3% compared with the commercial TPU double silver plated film product, that is, the gradient transition layer design (refractive index 1.5→1.9 continuous transition) greatly reduces the interface reflection loss, combined with the synergistic optimization of the double silver layer, realizes the balance of high transmittance and high infrared reflectivity; the square resistance is as low as 3.8Ω / sq, which is reduced by 58.7% compared with the commercial TPU double silver plated film product (9.2Ω / sq), which proves that the Ga-doped ZnO dielectric layer (resistivity≤1×10 -3 Ω·cm) effectively improves the carrier mobility. The crack density is only 0.05 / mm 2 after stretching 300%, which is lower than that of the commercial TPU double silver plated film product (6.2 / mm 2) 99.2% reduction, highlighting the adaptability of carboxylated carbon nanotube directional arrangement to TPU ductility; double 85 aging test: Al2O3 surface coating hydroxyl density ≥5 / nm 2 , forming Al-O-Ag chemical bonds inhibits silver layer oxidation, and the Si3N4 protective layer blocks environmental erosion.

[0301] Example 2

[0302] The performance of the comparative examples was tested, and the test design is shown in Table 2:

[0303] Table 2

[0304]

[0305] From the test results, it can be seen that: gradient transition layer integrity: comparative example 1 (no primer) due to the lack of refractive index gradient (1.5→1.9) and silane coupling agent bonding, resulting in a decrease in adhesion of 82% (0.5 vs 2.8 N / mm), interface reflection loss reduces infrared reflectivity by 10.3% (84.0% vs 93.7%). Necessity of directional arrangement: comparative example 2 (no electric field induction) due to the disordered dispersion of CNTs, the square resistance increases by 135% (8.9 vs 3.8 Ω / sq), high square resistance not only degrades performance parameters in flexible coating, but also causes functional failure (heating / touching / shielding failure) and exacerbates safety hazards (burning / short circuit), and disordered carbon tubes cause stress concentration, tensile crack density increases by 24 times (1.2 vs 0.05 mm 2 ). Interface chemical bonding: comparative example 3 (Al2O3 hydroxyl density is insufficient) due to insufficient Al-O-Ag bonding, silver layer oxidation after salt spray for 500h, infrared reflectivity decays by 22% (from 86.5% to 67.4%). Double silver layer structure advantage: comparative example 4 (single silver layer) due to the lack of optical interference enhancement of the second silver layer, infrared reflectivity decreases by 5.8% (88.3% vs 93.7%), and the single silver layer has insufficient stress buffering, tensile crack density increases by 64 times (3.2 vs 0.05 mm 2); it can be seen from the comparative example 5 (single silver layer and no medium layer) that the double silver layer enhances the infrared reflection through the optical interference effect of the medium layer, and the single silver layer cannot form multiple reflection interfaces; the single silver layer lacks the stress buffering effect of the medium layer, and the stress is directly transmitted to the silver layer when the TPU substrate is stretched, resulting in cracking; the medium layer has the function of blocking water and oxygen, and after being lost, the silver layer is directly exposed, accelerating oxidation; it can be further seen from the comparative example 7 (medium layer without Ga doping) that Ga doping can improve the carrier mobility of ZnO, and the resistivity of pure ZnO is higher, resulting in a decrease in conductivity; the carrier concentration of undoped ZnO is insufficient, which weakens the plasmon resonance effect and affects the infrared reflection performance; the compactness of pure ZnO is lower than that of ZnO: Ga, and the water and oxygen blocking ability is weakened, causing edge corrosion of the silver layer. The core role of the protective layer: although the adhesion of the comparative example 6 (without Si3N4 layer) does not decrease, the hardness is insufficient (<1000HV), which leads to water and oxygen penetration and causes serious oxidation corrosion (compared with no corrosion in example 1). Gradient transition cannot be replaced: the visible light transmittance of the comparative example 8 (without refractive index gradient) increases by 10.1% (79.5% vs 88.3%) due to the increase in interface reflection. Examples 1-3 using the present application scheme have significantly improved performance, and the performance of example 1 is the best, which should be considered as the preferred embodiment. In summary, the gradient transition layer (stress buffering + optical matching), the double silver layer (optical interference + conductivity enhancement), and the protective layer (environmental barrier) are synergistic, and the absence of any layer or parameter deviation will lead to significant degradation of mechanical, optical or weather resistance, proving the necessity of the synergistic effect of the three-layer structure.

[0306] The above disclosure is only a preferred embodiment of the present application, and of course cannot limit the scope of the rights of the present application, so the equivalent changes made according to the claims of the present application still fall within the scope covered by the present application.

Claims

1. A flexible plating material having a gradient transition layer and a double silver layer structure, characterized by, The flexible substrate layer, the gradient transition layer, the double silver layer; the gradient transition layer comprises a primer layer, a middle coating layer, and a top coating layer in sequence; the double silver layer comprises a first silver layer, a dielectric layer, a second silver layer, and a protective layer in sequence; the middle coating layer contains carboxylated carbon nanotubes; the carboxylated carbon nanotubes are arranged in a direction; the middle coating layer comprises a siloxane prepolymer, carboxylated carbon nanotubes, and a photoinitiator mixture; the carboxylated carbon nanotubes are arranged in a direction along a stretching direction; The primer layer comprises a polyurethane-modified acrylate, nano-SiO2 / TiO2 compound particles, and a silane coupling agent mixture; the refractive index of the primer layer changes in a gradient manner; in the primer layer, the mass ratio of the polyurethane-modified acrylate, the nano-SiO2 / TiO2 compound particles, and the silane coupling agent is 70-85:12-25:2-5; in the nano-SiO2 / TiO2 compound particles, the mass ratio of SiO2 to TiO2 changes in a gradient manner from 3:1 to 1:2, so that the refractive index of the primer layer changes in a gradient manner from 1.5 to 1.9; the particle size of the nano-SiO2 / TiO2 compound particles is 20-50 nm; The flexible substrate layer comprises a TPU substrate; the surface coating layer comprises an Al2O3 nanocrystalline layer; the first silver layer comprises an Ag target sputtering layer; the medium layer comprises a ZnO:Ga medium layer; the second silver layer comprises an Ag target sputtering layer; the protective layer comprises a Si3N4 protective layer; in the Al2O3 nanocrystalline layer, the surface hydroxyl density is ≥5 / nm 2 ; in the ZnO:Ga medium layer, the doping concentration of Ga comprises 2-5 wt %.

2. The flexible film-coated material having a gradient transition layer and a double silver layer structure according to claim 1, characterized in that, In the middle coating layer, the mass ratio of the siloxane prepolymer, the carboxylated carbon nanotubes, and the photoinitiator is 85-91:8-15:1-5.

3. The flexible film-coated material having a gradient transition layer and a double silver layer structure according to claim 1, characterized in that, The thickness of the flexible substrate layer is 50-150 μm; the thickness of the primer layer is 1.0-1.5 μm; the thickness of the middle coating layer is 0.5-1.0 μm; the thickness of the top coating layer is 20-50 nm; the thickness of the first silver layer is 10-15 nm; the thickness of the dielectric layer is 5-8 nm; the thickness of the second silver layer is 10-15 nm; and the thickness of the protective layer is 20-30 nm.

4. The method for preparing the flexible film-coated material with a gradient transition layer and a double silver layer structure according to claim 1, characterized in that, The method comprises the following steps: A. Pre-treatment of the flexible substrate layer; B. Coating the primer layer on the flexible substrate layer and heating and curing; C. Coating the middle coating layer on the primer layer, UV curing after electric field orientation induction; D. Spinning Al2O3 nanocrystal sol on the middle coating layer; forming the top coating layer by sol-gel method and sintering and curing; E. Magnetron sputtering the first silver layer on the top coating layer; F. Magnetron sputtering the dielectric layer on the first silver layer; G. Magnetron sputtering the second silver layer on the dielectric layer; H. Magnetron sputtering the protective layer on the second silver layer to obtain the flexible film-coated material with a gradient transition layer and a double silver layer structure.

5. The method of claim 4, wherein the method further comprises the step of: In step A, the pretreatment comprises plasma cleaning; in step B, the conditions of the heat curing comprise: a curing temperature of 80-100℃, a curing time of 2-30min, and a modulus of 50-100MPa after curing; in step C, the conditions of the UV curing comprise: a light wavelength of 365nm, and a light energy of 500-1200mJ / cm 2 ; in step D, the conditions of the sintering curing comprise: a sintering temperature of 120℃, and a sintering time of 5-30min; in step E, the conditions of the magnetron sputtering comprise: a sputtering power of 1-2kw, a sputtering atmosphere of 0.6Pa Ar, a sputtering temperature of 60-80℃, and a speed of 1-2m / min; in step F, the conditions of the magnetron sputtering comprise: a sputtering power of 30-50kw, a sputtering atmosphere of O2 and Ar mixed at a volume ratio of 1:9, a sputtering temperature of 60-80℃, and a speed of 2m / min; in step G, the conditions of the magnetron sputtering comprise: a sputtering power of 1-2kw, a sputtering atmosphere of 0.6Pa Ar, a sputtering temperature of 80℃, and a speed of 2m / min; in step H, the conditions of the magnetron sputtering comprise: a sputtering power of 0.5kw, a sputtering atmosphere of 0.6Pa Ar, a sputtering temperature of 60-80℃, and a speed of 2m / min. ​ 6. The method of claim 5, wherein the method further comprises the step of: In step A, the conditions of the plasma cleaning include: cleaning atmosphere Ar atmosphere, cleaning power 0.2 kW, cleaning time 2 min; in step B, the refractive index continuous gradient transition is realized by a microgravure coater step-by-step coating method, and the specific operation includes: adding the nano SiO2 / TiO2 compound particles in three batches, the mass ratio of SiO2 to TiO2 in the first batch of nano SiO2 / TiO2 compound particles is 3:1, pre-curing at 80℃ for 1 min after coating, the mass ratio of SiO2 to TiO2 in the second batch of nano SiO2 / TiO2 compound particles is 2:1, pre-curing at 80℃ for 1 min after coating, the mass ratio of SiO2 to TiO2 in the first batch of nano SiO2 / TiO2 compound particles is 1:2, pre-curing at 80℃ for 1 min after coating; in step C, the conditions of the electric field orientation induction include: electric field intensity 100~300 V / cm, action time 30~60 s; in step D, the solid content of the Al2O3 nanocrystal sol includes 5wt%, and the hydroxyl density is ≥5 / nm 2 ; in step E, the roughness of the first silver layer is <5nm; in step F, the resistivity of the dielectric layer is ≤1×10 -3 Ω·cm; in step G, the roughness of the second silver layer is <5nm; in step G, the hardness of the protective layer is ≥1800HV. ​

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