High-temperature-resistant ITO conductive film and preparation process thereof

Abstract

The invention relates to the technical field of conducting films, in particular to a high-temperature-resistant ITO conducting film and a preparation technology thereof.The preparation technology comprises the following steps that a base material layer is cleaned and dried for use; adhering an adhesive on the base material layer based on a spray deposition technology to form an adhesive layer; and growing a Zr-Nb co-doped ITO high-conductivity film on the adhesive layer based on a sputtering condition, and carrying out annealing treatment to prepare the high-temperature-resistant ITO conductive film. According to the high-temperature-resistant ITO conductive film provided by the invention, the thermal stability and the interface bonding performance can be enhanced, and the phenomena of delamination and residual adhesive transfer after high-temperature annealing can be effectively avoided.

Description

Technical Field

[0001] This invention belongs to the field of conductive film technology, and particularly relates to a high-temperature resistant ITO conductive film and its preparation process. Background Technology

[0002] ITO conductive film is a functional thin-film material that combines high light transmittance with good conductivity, and is widely used in touch displays, optoelectronic devices, solar cells, and flexible electronics. Traditional ITO films are mostly formed using magnetron sputtering or chemical vapor deposition processes. During high-temperature annealing or device encapsulation, these films are prone to stress cracking, delamination, or resistivity drift, severely affecting device stability and lifespan. Especially when used on flexible or composite substrates, the significant difference in thermal expansion coefficients between the ITO film and the organic layer, coupled with insufficient interfacial adhesion, makes them susceptible to microcracks during repeated thermal cycling, leading to a degradation of optical and electrical properties.

[0003] In the prior art, Chinese patent CN112457791A, concerning a high-temperature resistant protective film and its preparation process, and an ITO conductive film, discloses a high-temperature resistant protective film specifically for ITO conductive films. This film includes a protective film substrate layer and an adhesive layer covering the substrate layer. The adhesive layer is an acrylic adhesive layer, specifically an acrylic adhesive layer doped with 2-8 wt% diglycidyl hexahydrophthalic acid or 2-8 wt% diglycidyl tetrahydrophthalic acid, to improve the heat resistance of the ITO conductive film. In the actual preparation process of ITO conductive film, it often needs to go through processes such as hot annealing or high-temperature encapsulation. The temperature is usually between 250-350℃. Under such high temperature conditions, the acrylic adhesives and epoxy ester components used in the existing technology are difficult to maintain thermal stability for a long time, and are prone to softening, yellowing and other problems. This leads to a decrease in the bonding force between the adhesive layer and the substrate layer, which in turn causes the film layer to blister, delaminate or have residual adhesive pollution, ultimately affecting the light transmittance and conductivity of the ITO conductive film.

[0004] To overcome the shortcomings of the prior art, the present invention provides a high-temperature resistant ITO conductive film with good stability and strong substrate adhesion in high-temperature environments. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a high-temperature resistant ITO conductive film and its preparation process.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A process for preparing a high-temperature resistant ITO conductive film includes the following steps: S101. Clean the substrate layer and dry it for later use; S102. An adhesive layer is formed by attaching an adhesive onto a substrate layer using a spray deposition technique. S103. A Zr-Nb co-doped ITO high conductivity film is grown on the adhesive layer under sputtering conditions, and then annealed to obtain the high temperature resistant ITO conductive film. The thickness of the adhesive layer is 10-20 μm; The thickness of Zr-Nb co-doped ITO high conductivity film is 60-100 nm; The method for preparing the adhesive includes the following steps: S201. Mix colloidal silica and anhydrous ethanol at a volume ratio of 1:(4-5), and sonicate at 250-350W for 10-15 minutes to obtain a colloidal dispersion. S202. Add phenyltriethoxysilane and anhydrous ethanol to the colloidal dispersion, stir, then add deionized water and acetic acid solution, heat and stir to obtain the first material; S203. Measure 3-glycidyloxypropyltrimethoxysilane and (3-mercaptopropyl)trimethoxysilane and anhydrous ethanol in a volume ratio of (4-6):(1-2):(28-30), and stir at 250-350 rpm for 8-12 min to obtain the second material. S204. The first material is added dropwise to the second material at a rate of 0.5-1.0 mL / min. After the dropwise addition is completed, deionized water is added, and acetic acid solution is added to adjust the pH of the system to 4.0-4.5. The mixture is stirred at 300-500 rpm at room temperature for 10-12 hours to obtain a hybrid solution. S205. Mix isophorone diamine, leveling agent and hybrid solution in a volume ratio of 1:0.1:(90-110), stir and let stand for 1-2 hours to obtain a high-temperature resistant adhesive.

[0007] Furthermore, the conditions for the spray deposition technology in step S102 are: substrate preheating at 50-60°C, atomization pressure of 0.6-1.2 bar, nozzle distance from substrate of 12-16 cm, and nozzle moving speed of 300 mm / s.

[0008] Furthermore, step S102 also includes placing the substrate layer containing the adhesive into an oven, curing it by staged heating, and cooling it to room temperature.

[0009] Furthermore, the staged temperature curing conditions are as follows: the first stage is cured at 60-80℃ for 10-15 min, the second stage is cured at 80-100℃ for 25-30 min, and the third stage is cured at 100-110℃ for 40-45 min.

[0010] Furthermore, the sputtering conditions were as follows: co-sputtering with an ITO ceramic target and a Zr-Nb2O5 target; the weight ratio of indium oxide to tin oxide in the front target was 9:1, and the DC sputtering power was 30-50 W; the weight ratio of zirconium to niobium pentoxide in the rear target was 3:1, and the RF sputtering power was 8-10 W; the vacuum degree was 10⁻⁴ Pa; the working pressure was 0.35-0.45 Pa; the argon flow rate was 45 sccm; and the oxygen flow rate was 0.3 sccm.

[0011] Further, in step S202, the volume ratio of phenyltriethoxysilane: anhydrous ethanol: deionized water is 1:(10-12):(0.4-0.5); the amount of acetic acid added is 0.2-0.4% of the total volume of phenyltriethoxysilane, anhydrous ethanol and deionized water.

[0012] Furthermore, the substrate layer is one of the following: glass layer, PET layer, and PI layer.

[0013] This invention provides a process for preparing a high-temperature resistant ITO conductive film. The ITO conductive film includes a substrate layer, an adhesive layer attached to the substrate layer, and a Zr-Nb co-doped ITO high conductivity film attached to the upper surface of the adhesive layer.

[0014] The beneficial effects of this invention are as follows: By introducing an organic-inorganic hybrid high-temperature resistant adhesive layer between the ITO film and the substrate, the thermal stability and interfacial bonding performance of the ITO film can be enhanced. This adhesive uses silane precursors, including 3-glycidoxypropyltrimethoxysilane, (3-mercaptopropyl)trimethoxysilane, phenyltriethoxysilane, and colloidal silica as its main components. Through reaction, a hybrid network structure is formed where a Si–O–Si inorganic framework and flexible organic segments coexist. The introduced thiol groups can chemically bond with the hydroxyl groups on the ITO film surface, significantly improving interfacial adhesion and preventing delamination and residual adhesive transfer after high-temperature annealing. Attached Figure Description

[0015] Figure 1 This is a process flow diagram for preparing the high-temperature resistant ITO conductive film of the present invention. Figure 2 This is a process flow diagram for preparing the adhesive of the present invention; Figure 3 This is a schematic diagram of the ITO conductive film layer structure prepared according to the present invention.

[0016] In the figure: 1. Substrate layer; 2. Adhesive layer; 3. Zr-Nb co-doped ITO high conductivity film. Detailed Implementation

[0017] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, the reagents used in this invention are all conventional reagents in the art and can be obtained commercially. Unless otherwise specified, the experimental methods used in this invention are all conventional experimental methods in the art.

[0018] See attached document Figure 1 -Appendix Figure 3 As shown, the present invention provides: Example 1 1. Preparation of adhesives S201. Take 3 mL of Ludox TM-50 colloidal silica into a beaker, add 12 mL of anhydrous ethanol solution, and sonicate at 250 W power for 10 min to obtain a colloidal dispersion. S202. Add 3.75 mL of phenyltriethoxysilane and 37.5 mL of anhydrous ethanol solution to the colloidal dispersion, and stir with a magnetic stirrer until the system is clear and homogeneous; then add 1.5 mL of deionized water and 0.09 mL of acetic acid solution, and place the beaker on a hot plate to heat to 50°C, and stir at 400 rpm for 60 min to obtain the first material; S203. Mix 7.5 mL of 3-glycidyloxypropyltrimethoxysilane, 1.25 mL of (3-mercaptopropyl)trimethoxysilane and 37.5 mL of anhydrous ethanol solution, and stir at 250 rpm for 8 min at room temperature to obtain the second material. S204. The first material is slowly added dropwise to the second material at a rate of 0.5 mL / min, while stirring at 300 rpm during the dropwise addition. After the dropwise addition is completed, 0.2% of the total volume of deionized water is added, and the pH of the system is adjusted to 4.0 using acetic acid solution. Then, the reaction is continued at 300 rpm for 10 h at room temperature to obtain a hybrid solution. S205. Take 135 mL of the hybrid solution, add 1.5 g of isophorone diamine and 0.15 g of leveling agent BYK-333 to it, stir at 200 rpm for 10 min at 30℃, and let stand for 1 h to obtain a high-temperature resistant adhesive.

[0019] 2. Preparation of ITO conductive film S101. Ultrasonically clean the substrate layer 1, which is a glass layer, using deionized water and ethanol, and dry it for later use. S102. Adjust the adhesive to 3 cPs with anhydrous ethanol solution and spray it onto the substrate surface using a spray deposition method. The conditions are: atomizing pressure 0.6 bar, nozzle distance 12 cm from the substrate, nozzle moving speed 300 mm / s, and substrate preheating 50°C. After spraying, place the substrate layer containing the adhesive into an oven and cure it using staged heating. The first stage is cured at 60°C for 15 min, the second stage is cured at 80°C for 30 min, and the third stage is cured at 110°C for 45 min. After curing, slowly cool to room temperature to form adhesive layer 2, which has a thickness of 10 μm. S103. On adhesive layer 2, co-sputtering is performed using an ITO ceramic target and a Zr-Nb2O5 target; the weight ratio of indium oxide to tin oxide in the front target is 9:1, and the DC sputtering power is 30 W; the weight ratio of zirconium to niobium pentoxide in the rear target is 3:1, and the RF sputtering power is 8 W; vacuum level is 10. -4 Under sputtering conditions of 0.35 Pa working pressure, 45 sccm argon flow rate, and 0.3 sccm oxygen flow rate, a Zr-Nb co-doped ITO high conductivity film 3 was grown with a thickness of 60 nm. The film was then annealed at 250 °C for 3 min to obtain a high-temperature resistant ITO conductive film.

[0020] Example 2 1. Preparation of adhesives S201. Take 3 mL of Ludox TM-50 colloidal silica into a beaker, add 13.5 mL of anhydrous ethanol solution, and sonicate at 300 W for 12 min to obtain a colloidal dispersion. S202. Add 3.75 mL of phenyltriethoxysilane and 41.25 mL of anhydrous ethanol solution to the colloidal dispersion, and stir with a magnetic stirrer until the system is clear and homogeneous; then add 1.5 mL of deionized water and 0.14 mL of acetic acid solution, and place the beaker on a hot plate to heat to 50°C, and stir at 500 rpm for 70 min to obtain the first material; S203. Mix 5 mL of 3-glycidyloxypropyltrimethoxysilane, 1.25 mL of (3-mercaptopropyl)trimethoxysilane and 35 mL of anhydrous ethanol solution, and stir at 300 rpm for 10 min at room temperature to obtain the second material. S204. The first material is slowly added dropwise to the second material at a rate of 0.8 mL / min, while stirring at 300 rpm during the dropwise addition. After the dropwise addition is completed, 0.3% of the total volume of deionized water is added, and the pH of the system is adjusted to 4.2 using acetic acid solution. Then, the reaction is continued at 400 rpm for 11 h at room temperature to obtain a hybrid solution. S205. Take 150 mL of the hybrid solution, add 1.5 g of isophorone diamine and 0.15 g of leveling agent BYK-333 to it, stir at 250 rpm for 12 min at 35℃, and let stand for 1 h to obtain a high-temperature resistant adhesive.

[0021] 2. Preparation of ITO conductive film S101. Ultrasonically clean the substrate layer 1, which is a PET layer, using deionized water and ethanol, and then dry it for later use. S102. Adjust the high-temperature resistant adhesive to 4 cPs with anhydrous ethanol solution, and spray it onto the substrate surface using a spray deposition method. The conditions are: atomizing gas pressure 1.0 bar, nozzle distance from the substrate 14 cm, nozzle moving speed 300 mm / s, and substrate preheating 55℃. After spraying, place the substrate layer containing the adhesive into an oven and cure it using staged heating. The first stage is cured at 70℃ for 12 min, the second stage is cured at 90℃ for 28 min, and the third stage is cured at 100℃ for 42 min. After curing, slowly cool to room temperature to form adhesive layer 2, which is 15 μm thick. S103. On adhesive layer 2, co-sputtering is performed using an ITO ceramic target and a Zr-Nb2O5 target; the weight ratio of indium oxide to tin oxide in the front target is 9:1, and the DC sputtering power is 40W; the weight ratio of zirconium oxide to niobium pentoxide in the rear target is 3:1, and the RF sputtering power is 9W; vacuum level is 10. -4 Under sputtering conditions of 0.40 Pa, 45 sccm argon flow rate, and 0.3 sccm oxygen flow rate, a Zr-Nb co-doped ITO high conductivity film 3 was grown with a thickness of 80 nm. The film was then annealed at 250 °C for 3 min to obtain a high-temperature resistant ITO conductive film.

[0022] Example 3 1. Preparation of adhesives S201. Take 3 mL of Ludox TM-50 colloidal silica into a beaker, add 15 mL of anhydrous ethanol solution, and sonicate at 350 W for 15 min to obtain a colloidal dispersion. S202. Add 3.75 mL of phenyltriethoxysilane and 37.5 mL of anhydrous ethanol solution to the colloidal dispersion, and stir with a magnetic stirrer until the system is clear and homogeneous; then add 1.875 mL of deionized water and 0.20 mL of acetic acid solution, and place the beaker on a hot plate to heat to 50°C, and stir at 600 rpm for 90 min to obtain the first material; S203. Mix 12.5 mL of 3-glycidyloxypropyltrimethoxysilane, 2.5 mL of (3-mercaptopropyl)trimethoxysilane and 72.5 mL of anhydrous ethanol solution, and stir at 350 rpm for 12 min at room temperature to obtain the second material. S204. The first material is slowly added dropwise to the second material at a rate of 1.0 mL / min, while stirring at 300 rpm during the dropwise addition. After the dropwise addition is completed, 0.4% of the total volume of deionized water is added, and the pH of the system is adjusted to 4.5 using acetic acid solution. Then, the reaction is continued at 500 rpm for 12 h at room temperature to obtain a hybrid solution. S205. Take 165 mL of the hybrid solution, add 1.5 g of isophorone diamine and 0.15 g of leveling agent BYK-333 to it, stir at 300 rpm for 15 min at 40℃, let stand for 2 h to obtain a high temperature resistant adhesive.

[0023] 2. Preparation of ITO conductive film S101. Ultrasonically clean the substrate layer 1, which is a PI layer, using deionized water and ethanol, and dry it for later use. S102. Adjust the high-temperature resistant adhesive to 5 cP with anhydrous ethanol solution and spray it onto the substrate surface using a spray deposition method. The conditions are: atomizing pressure 1.2 bar, nozzle distance from the substrate 16 cm, nozzle moving speed 300 mm / s, and substrate preheating to 60℃. After spraying, place the substrate layer containing the adhesive into an oven and cure it using staged heating. The first stage is cured at 80℃ for 10 min, the second stage is cured at 100℃ for 25 min, and the third stage is cured at 110℃ for 40 min. After curing, slowly cool to room temperature to adhere the adhesive to the substrate layer to form adhesive layer 2 with a thickness of 20 μm. S103. On adhesive layer 2, co-sputtering is performed using an ITO ceramic target and a Zr-Nb2O5 target; the weight ratio of indium oxide to tin oxide in the front target is 9:1, and the DC sputtering power is 50W; the weight ratio of zirconium to niobium pentoxide in the rear target is 3:1, and the RF sputtering power is 10W; vacuum level 10. -4A Zr-Nb co-doped ITO high conductivity film 3 was grown under sputtering conditions of 0.45 Pa, 45 sccm argon flow rate, and 0.3 sccm oxygen flow rate. The thickness of the Zr-Nb co-doped ITO high conductivity film 3 was 100 nm. The film was then annealed at 250 °C for 3 min to obtain a high-temperature resistant ITO conductive film.

[0024] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the adhesive preparation does not contain the second material. After the first material is prepared, isophorone diamine and leveling agent BYK-333 are mixed with the first material at a volume ratio of 1:0.1:90 to obtain the adhesive. All other steps are the same.

[0025] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the adhesive used is the high-temperature resistant protective film and its preparation process described in patent CN 112457791A, and the adhesive used in the ITO conductive film. The adhesive is then bonded between the substrate layer of the ITO conductive film prepared in this invention and the Zr-Nb co-doped ITO high conductivity film.

[0026] Performance testing The high-temperature resistant ITO conductive films prepared in each embodiment and comparative example were subjected to thermal shrinkage tests at 150℃ for 60 min, and the warpage of the composite consisting of the adhesive layer and the Zr-Nb co-doped ITO high-conductivity film was tested according to standard GB / T 25257-2010.

[0027] Table 1 Performance test results of each embodiment and comparative example

[0028] Note: The thermal shrinkage rates of the adhesive layer are TD1 and MD1, and the thermal shrinkage rates of the Zr-Nb co-doped ITO high-conductivity film are TD2 and MD2; TD1-TD2 is the difference in lateral thermal shrinkage rates between the adhesive layer and the Zr-Nb co-doped ITO high-conductivity film; MD1-MD2 is the difference in longitudinal thermal shrinkage rates between the adhesive layer and the Zr-Nb co-doped ITO high-conductivity film.

[0029] As shown in Table 1, the high-temperature resistant ITO conductive film prepared by this invention exhibits good thermal dimensional stability under different adhesive layer thicknesses, maintaining structural integrity under high-temperature conditions. In Examples 1-3, the TD1-TD2 values ​​were all controlled within the range of 0.01-0.06%, and MD1... The MD2 value remained at a low level of 0.00-0.03%, corresponding to a warpage of 0.4-1.2 mm, significantly lower than that of Comparative Examples 1 and 2. These results indicate that as the difference between transverse and longitudinal thermal shrinkage decreases, the warpage of the ITO conductive film at high temperatures is significantly reduced, maintaining high flatness and interface stability.

[0030] In summary, the adhesive prepared by this invention not only has low thermal shrinkage characteristics, but also effectively suppresses the accumulation of thermal stress in the ITO conductive film, so that it can maintain a stable structural morphology and performance after high-temperature annealing or subsequent heat processing, and has good high-temperature resistance.

[0031] 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 spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for preparing a high-temperature resistant ITO conductive film, characterized in that, Includes the following steps: S101. Clean the substrate layer and dry it for later use; S102. An adhesive layer is formed by attaching an adhesive onto a substrate layer using a spray deposition technique. S103. A Zr-Nb co-doped ITO high conductivity film is grown on the adhesive layer under sputtering conditions, and then annealed to obtain the high temperature resistant ITO conductive film. The thickness of the adhesive layer is 10-20 μm; The thickness of Zr-Nb co-doped ITO high conductivity film is 60-100 nm; The method for preparing the adhesive includes the following steps: S201. Mix colloidal silica and anhydrous ethanol at a volume ratio of 1:(4-5), and sonicate at 250-350W for 10-15 minutes to obtain a colloidal dispersion. S202. Add phenyltriethoxysilane and anhydrous ethanol to the colloidal dispersion, stir, then add deionized water and acetic acid solution, heat and stir to obtain the first material; S203. Measure 3-glycidyloxypropyltrimethoxysilane and (3-mercaptopropyl)trimethoxysilane and anhydrous ethanol in a volume ratio of (4-6):(1-2):(28-30), and mix them with the mixture. Stir at 250-350 rpm for 8-12 min to obtain the second material. S204. The first material is added dropwise to the second material at a rate of 0.5-1.0 mL / min. After the addition is complete, deionized water is added, and acetic acid solution is added to adjust the pH of the system to 4.0-4.

5. The mixture is stirred at 300-500 rpm for 10-12 h at room temperature to obtain a hybrid solution. S205. Mix isophorone diamine, leveling agent and hybrid solution in a volume ratio of 1:0.1:(90-110), stir and let stand for 1-2 hours to obtain a high-temperature resistant adhesive.

2. The preparation process of a high-temperature resistant ITO conductive film according to claim 1, characterized in that, The conditions for the spray deposition technology in step S102 are: substrate preheating to 50-60℃, atomization pressure of 0.6-1.2 bar, nozzle distance from substrate of 12-16 cm, and nozzle moving speed of 300 mm / s.

3. The preparation process of a high-temperature resistant ITO conductive film according to claim 1, characterized in that, Step S102 further includes placing the substrate layer containing the adhesive into an oven, curing it by staged heating, and cooling it to room temperature.

4. The preparation process of a high-temperature resistant ITO conductive film according to claim 3, characterized in that, The segmented temperature-curing conditions are as follows: the first stage is cured at 60-80℃ for 10-15 min, the second stage is cured at 80-100℃ for 25-30 min, and the third stage is cured at 100-110℃ for 40-45 min.

5. The preparation process of a high-temperature resistant ITO conductive film according to claim 1, characterized in that, The sputtering conditions were as follows: co-sputtering with an ITO ceramic target and a Zr-Nb2O5 target; the weight ratio of indium oxide to tin oxide in the front target was 9:1, and the DC sputtering power was 30-50 W; the weight ratio of zirconium oxide to niobium pentoxide in the rear target was 3:1, and the RF sputtering power was 8-10 W; the vacuum level was 10. -4 Pa; working pressure is 0.35-0.45 Pa; argon flow rate is 45 sccm; oxygen flow rate is 0.3 sccm.

6. The preparation process of a high-temperature resistant ITO conductive film according to claim 1, characterized in that, In step S202, the volume ratio of phenyltriethoxysilane: anhydrous ethanol: deionized water is 1:(10-12):(0.4-0.5). The amount of acetic acid added is 0.2-0.4% of the total volume of phenyltriethoxysilane, anhydrous ethanol, and deionized water.

7. The preparation process of a high-temperature resistant ITO conductive film according to claim 1, characterized in that, The substrate layer is one of glass, PET, or PI.

8. A high-temperature resistant ITO conductive film, characterized in that, The high-temperature resistant ITO conductive film is prepared according to the method described in any one of claims 1-7. The ITO conductive film includes a substrate layer, an adhesive layer attached to the substrate layer, and a Zr-Nb co-doped ITO high conductivity film attached to the upper surface of the adhesive layer.

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