A method for curing a layer deposited on a substrate and a substrate manufactured using said method

Abstract

The present invention relates to a method for curing a layer deposited on a substrate, wherein the layer comprises a coating formulation containing hydrolyzable Si-X groups, wherein X is selected from halogen, C1-C6 alkoxy, hydrogen, -NH-Si, or -NH2. The coating formulation dissolves in a solvent when applied to the substrate. The method comprises the steps of drying the layer at a temperature not exceeding 20°C above the boiling point of the solvent and exposing the layer to curing vapor. Furthermore, the present invention relates to a substrate manufactured using the above method.

Description

Technology Field

[0001] The present invention relates to a method for curing a layer comprising a coating formulation containing hydrolyzable Si-X groups, and a substrate comprising a coating prepared using the method, wherein X is selected from halogen, C1-C6 alkoxy, hydrogen, -NH-Si, and -NH2. Background Technology

[0002] Compounds containing hydrolyzable Si-X groups are commonly used as main components or additives in coating formulations. The curing of such coatings involves the formation of silanols through the hydrolysis of Si-X groups, followed by the formation of Si-O-Si bonds through condensation reactions between the silanol groups. These compounds are considered environmentally friendly because they do not require or contain toxic curing agents or toxic groups used as part of the molecule or as separate additives. Furthermore, Si-O-Si bonds are highly stable against a wide variety of chemicals as well as ultraviolet (UV) radiation and other environmental factors.

[0003] The Si atoms of Si-X or other Si atoms within the molecule may be bonded to organic groups such as methyl, ethyl, phenyl, or vinyl (CH=CH2). These Si-organic groups are highly inert, thereby imparting excellent hydrophobicity and even oleophobicity to the coating. For this reason, these compounds are used as anti-soiling coatings or for surface modification to impart anti-soiling properties. Examples of compounds containing hydrolyzable Si-X groups include (poly)alkoxysilanes, (poly)halosilanes, and (poly)silazanes.

[0004] Coatings containing hydrolyzable Si-X groups are frequently maintained to cure in the ambient atmosphere; that is, curing occurs due to moisture in the air. This curing method is simple and environmentally friendly as it does not utilize toxic curing agents such as tin-based compounds. However, this curing is typically performed top-down, meaning the top surface of the coating cures before or faster than the interior. This results in the following:

[0005] 1. Curing generally deteriorates over time, as the already cured top surface can act to delay moisture penetration. This is particularly pronounced when Si atoms are bonded to organic groups, such as methyl groups and vinyl groups of polysilazane. These Si-alkyl groups (e.g., Si-CH3) or Si-aryl groups (e.g., Si-phenyl groups) are hydrophobic and inert, which can hinder moisture penetration. In fact, in the field of organic chemistry, they exhibit the second highest inertness and hydrophobicity after carbon-fluorine bonds (e.g., CF2 or CF3). For this reason, polydimethylsiloxane (PDMS) is widely used as a water-repellent surface.

[0006] 2. Curing may be interrupted depending on weather conditions, and as a result, the interior of the coating remains uncured while only the upper surface is cured, so the physical properties may vary depending on the width direction of the coating.

[0007] Among compounds having hydrolyzable Si-X groups used in coating formulations, organopolysilazane (OPSZ) is popular and widely used for vehicle coatings to impart anti-fouling properties to vehicles and protect automotive paints from UV rays. In addition, OPSZ coatings are also applied to photovoltaic (PV) glass, windows, eyeglasses, touchscreens, etc., to provide anti-fouling or easy-to-clean surfaces.

[0008] The generally recommended curing method for OPSZ is to cure by holding it in an ambient environment, and it may take up to 7 days to reach curing (up to 95%). The inventors noted that OPSZ coatings, whether commercially available or self-formulated, exhibit a very limited or poor curing state even after heating at 200°C for 1 to 2 hours. Therefore, using such high temperatures, which may not be practical for some substrates, such as plastics, does not necessarily lead to satisfactory curing. Even after raising the relative humidity to over 50%, the inventors [researched] at approximately 900 cm -1 As evidenced by the disappearance of the FT-IR peak of the NH (or represented as Si-NH or Si-NH-Si) bonds appearing in [the image], it was confirmed that curing remains insufficient or limited even at elevated temperatures. Therefore, there is still a need for a cost-effective and rapid process leading to (nearly) complete curing of polysilazanes and other compounds containing hydrolyzable Si-X groups.

[0009] Patent application WO2023 / 282768 A1 discloses an improved curing method for polysilazanes and comprises the following steps: a) drying for 10 minutes in an oven maintained at 80°C; and then b) curing in a high-humidity atmosphere containing H2O2 vapor. The authors of the said document noted that for coating formulations not containing the crosslinking catalyst tetrabutylammonium fluoride (TBAF), the curing process—that is, the formation of silanol by hydrolysis of Si-NH groups and the formation of Si-O-Si through a subsequent condensation reaction—is limited, just as it is for TBAF-containing coatings maintained to cure under ambient conditions. Tetrabutylammonium chloride (TBAC) is also known to promote the curing of polysilazanes. TBAC and TBAF belong to a group called quaternary ammonium salts (QAS). QAS hydrates easily, and this may be the reason they can promote the curing of polysilazane.

[0010] A polysilazane coating method is also disclosed in WO 2022 / 002844 A1. In the above method, a polysilazane, a catalyst (TBAF), and a reactive nanomaterial and / or reactive molecule are introduced into a coating composition container, and the solution is mixed for a predetermined time. Subsequently, within a further predetermined time after the mixing step, the mixed solution is applied to a substrate to form a coating layer thereon, and subsequently cured.

[0011] The object of the present invention is to improve the curing method of a coating containing hydrolyzable Si-X groups. A second object of the present invention is to enhance the curing of a polysilazane coating formulation that does not contain QAS, such as TBAF.

[0012] Summary of the Invention

[0013] The present invention provides a method for curing a layer deposited on a substrate, wherein the layer comprises a coating formulation containing a hydrolyzable Si-X group, wherein X is selected from a halogen, a C1-C6 alkoxy, hydrogen, -NH-Si, or -NH2, and the coating formulation is dissolved in a solvent, and the method comprises the following steps:

[0014] a) a step of heating the layer at a temperature not exceeding 20°C above the boiling point of the solvent; and

[0015] b) A step of exposing the above layer to curing steam.

[0016] In addition, the present invention provides a substrate manufactured using the method of the above invention. Specific details for implementing the invention

[0017] The present invention provides a method for curing a layer deposited on a substrate in an improved and rapid manner, wherein the layer comprises a coating formulation containing hydrolyzable Si-X groups, wherein X is selected from halogens, alkoxy groups, hydrogen, NH-Si, and NH2. Examples of compounds containing hydrolyzable Si-X groups include (poly)alkoxysilanes, (poly)halosilanes, and (poly)silazanes. Their hydrolysis and condensation reactions can be summarized as follows:

[0018] (1) Si-X + H2O = Si-OH + HX

[0019] (2) Si-OH + Si-OH = Si-O-Si + H2O

[0020] Here, X may be a halogen, preferably chlorine or bromine (e.g., chlorine in dimethyldichlorosilane), an alkoxy group—e.g., ethoxy in (3-aminopropyl)triethoxysilane (APTES) and methoxy in methyltrimethoxysilane—or hydrogen (e.g., hydrogen in polysilazane) and NH-Si or NH2 (e.g., NH-Si or NH2 in polysilazane). The hydrolysis of Si-NH-Si in polysilazane has different stoichiometry, resulting in the formation of two silanol molecules and ammonia:

[0021] (3) Si-NH-Si + H2O = Si-OH + Si-NH2

[0022] (4) Si-NH2 + H2O = Si-OH + NH3

[0023] Therefore, the combined equation is as follows:

[0024] (5) Si-NH-Si + 2H2O = 2Si-OH + NH3

[0025] Therefore, in reaction equations 3 and 4, X is NH-Si and NH2, respectively.

[0026] A coating formulation comprising a hydrolyzable Si-X group (where X is selected from halogens, C1-C6 alkoxy groups, hydrogen, NH-Si, or NH2) may be dissolved in one or more solvents. The solvent may be a polar aprotic solvent and / or a non-polar solvent. When X in Si-X is an alkoxy, a polar solvent such as ethanol or acetone may be used. The solvent may be an anhydrous solvent. In some embodiments, all components are completely dissolved or suspended in a stable suspension state before being introduced into the coating composition vessel. In other embodiments, one or more liquid components are introduced into the coating composition vessel in a clean state (neat) without the presence of a solvent, and all remaining components are completely dissolved or suspended in a stable suspension state before being introduced into the coating composition vessel. In some embodiments, all components are dissolved or suspended in the same solvent. In other embodiments, different solvents are used for two or more components. In some embodiments, the solvent is selected from a list including, but not limited to, dimethyl sulfoxide (DMSO), n-butyl acetate, tert-butyl acetate, tetrahydrofuran (THF), dimethylformamide (DMF), 2-methyltetrahydrofuran (MTHF), dibutyl ether (DBE), and xylene. In a preferred embodiment, the coating composition containing a substantial amount of PHPS comprises only nonpolar solvents such as dibutyl ether and xylene.

[0027] The above material may be glass, ceramic, metal, polymer (plastic), wood, or composite material. The material may have rigidity or flexibility.

[0028] When a coating formulation is deposited as a layer on a substrate, the layer is heated at a temperature not exceeding 20°C above the boiling point of the solvent. Preferably, the temperature does not exceed 10°C above the boiling point of the solvent. Alternatively, the temperature may be equal to the boiling point of the solvent. In an embodiment of the present invention, the layer may be heated at a temperature 10°C to 20°C lower than the boiling point of the solvent. In one embodiment, when butyl acetate is used as the solvent, the temperature may be 30°C to 60°C lower than the boiling point of the solvent.

[0029] As previously explained, curing in a humidified atmosphere is performed as a top-down process. This means that curing begins in the top layer, which is more exposed to moisture, or proceeds more rapidly in the top layer. A natural consequence of this is that curing may stop due to the formation of a cured, impermeable layer. Once this cured top layer reaches a sufficient thickness, it will provide a dry-to-touch state and good surface properties (e.g., a high water contact angle) even if curing to depth does not occur. However, depth curing is important to ensure a product capable of maintaining durability in harsh applications.

[0030] The heating step described above can promote more uniform drying throughout the thickness direction of the layer. Excessive drying or uneven drying means that the upper surface becomes drier and, in contrast, the lower layer becomes wetter.

[0031] The temperature and time of the heating step can be preferably controlled so that the coating layer is not completely dried.

[0032] Drying implies densifying the coating, which entails a closer packing of polysilazane molecules. As a result, steric hindrance increases, and the penetration of curing vapor is further obstructed. The dense arrangement of polysilazane molecules can cause the inert top segment to form more rapidly during the drying process and / or the initial stages of curing vapor treatment, thereby blocking the penetration of curing vapor into the underlying hydrolyzable polar Si-X groups.

[0033] The above drying may be performed within a time of 20 to 30 minutes or less. The above drying may be performed for a time of 10 seconds to 30 minutes, preferably 20 seconds to 20 minutes, preferably 10 seconds to 10 minutes, preferably 20 seconds to 5 minutes, preferably 20 seconds to 2 minutes, or preferably 30 seconds to 1.5 minutes.

[0034] The curing vapor includes compounds known in the art for hydrolyzing or promoting hydrolysis of Si-X groups. The curing vapor may include water, H2O2, NH3, organic / inorganic acids, or a combination of two or more compounds.

[0035] The hardened compound may originally exist as a liquid and therefore must be converted to a vapor phase. The generation of vapor can be achieved by any suitable process, for example, using heat.

[0036] The generation of steam may be achieved by using any other process known in the art, for example, a process used to generate steam from water for humidification purposes. Examples thereof include ultrasonic humidifiers and impeller humidifiers.

[0037] In a preferred embodiment, the curing vapor is generated using an ultrasonic humidifier. The ultrasonic humidifier atomizes (vaporizes) a liquid into a fine mist using ultrasonic frequencies and may be referred to herein as an ultrasonic vaporizer.

[0038] An impeller steam generator uses a high-speed rotating disk (impeller) to pulverize a liquid into fine droplets that can be suspended in the air, and may be referred to as an impeller vaporizer in this specification.

[0039] The curing steam may contain a mixture of water and H2O2. The curing steam may contain 1 to 30 wt% of H2O2 in water, and preferably 5 to 25 wt% of H2O2 in water. Preferably, the concentration of H2O2 in water is 10 wt% or more.

[0040] The curing steam may contain a mixture of ammonia and water. The curing steam may contain 0.25 to 30 wt% of NH3 in water, and preferably contains 2 to 20 wt% of NH3 in water.

[0041] The weight percentages of H2O2 and NH3 in the water mentioned above refer to the composition of the liquid composition from which hardened vapor is generated. It is assumed that the generated vapor has the same concentration as the liquid.

[0042] After the coating layer is exposed to curing steam, it may be heated to complete or further enhance the curing process. Preferably, the temperature does not exceed 200°C, and the heating time is 60 minutes or less.

[0043] In the curing experiment described below, the coating formulation includes polysilazane. In addition, the present curing method can also be performed on coating formulations containing a hydrolyzable Si-X group in which X is selected from a halogen or alkoxy group.

[0044] experiment

[0045] General information regarding the experiment:

[0046] * Unless otherwise specified, hardening vapor is 20 wt% H2O2 in water.

[0047] * For the sake of brevity, wt% H2O2 vapor refers to vapor generated from an aqueous solution containing equal percentages of H2O2. That is, H2O2 in the liquid and gaseous phases The concentration is considered to be the same.

[0048] * H2O2 vapor is generated by an ultrasonic humidifier and is redirected or uniformly distributed by air flowing from an oven fan. Since the vapor generated by the humidifier is soft and easily sways, air / gas is essential to redirect and distribute the vapor for uniform processing of the sample.

[0049] * The curing vapor is any vapor capable of hydrolyzing the polar groups within polysilazane to form silanol (Si-OH).

[0050] * The curing grade is evaluated from 6.75 (substantially uncured) to 1 (best cured) and is classified into 1 to 1.125 (best cured, EC); 1.25 to 1.5 (very good cured, VVGC); 1.75 to 2 (very good cured, VGC); 2.25 to 2.75 (good cured, GC); 3 to 3.5 (average cured, FC); 3.75 (borderline cured, BC); 4 to 4.5 (poor cured, PC); 4.75 to 5.5 (very poor cured, VPC); and 5.75 to 6.75 (extremely poor cured, EPC).

[0051] * The hardening evaluation is based on the results measured by FT-IR.

[0052] * D1500RC is an organic polysilazane containing (3-aminopropyl)triethoxysilane (APTES) to ensure rapid curing. Its structure is believed to be as follows:

[0053]

[0054] (a, b, and c are proprietary information).

[0055] * 7640 Permanent Profi Protect (PP) is a commercial formulation of organic polysilazane from Creative Chemical Manufacturers (CCM). According to CCM, the formulation contains APTES. n-butyl acetate is the main solvent and accounts for 35 wt% or more and less than 55 wt% of the composition, organic polysilazane accounts for 15 wt% or more and less than 35 wt%, and APTES accounts for 5 wt% or more and less than 10 wt%.

[0056] * The boiling point of n-butyl acetate is 126°C.

[0057] * TBAF is a solution of tetrabutylammonium fluoride (0.5 wt%) in THF. TBAF acts as a crosslinking catalyst to prevent or minimize fragmentation.

[0058] * TG4 is a solution (5.5 wt%) of TEGO® Glide 410 (Evonik) in THF. TG4 is a polyether-modified siloxane and acts as a leveling agent.

[0059] * The boiling point of THF is 66℃.

[0060] * B17 is a dumbbell-type POSS solution (10 wt%) in THF. Its structure is shown below:

[0061]

[0062] * A85 is a 10 wt% solution (open-cage POSS) [trisilanol isobutyl POSS (HybridPlastics product)] in THF. The structure is shown below:

[0063]

[0064] R = Isobutyl

[0065] Coating formulation:

[0066] * B17-66:

[0067] A: 2000 μL D1500RC + 1000 μL TG4

[0068] B: 2000 μL B17 POSS + 660 μL TBAF + 250 μL THF

[0069] * B17-80

[0070] A: 1182 μL D1500RC + 590 μL TG4

[0071] B: 1420 μL B17 POSS + 400 μL TBAF + 2318 μL THF

[0072] * A85-8

[0073] A: 1182 μL D1500RC + 590 μL TG4

[0074] B: 1182 μL A85 + 400 μL TBAF + 2550 μL THF

[0075] * PP-1:

[0076] 3940 μL PP + 3940 μL n-butyl acetate

[0077] * D1500-R2:

[0078] 2000 μL D1500RC + 3910 μL THF

[0079] * D1500-R9:

[0080] 2000 μL D1500 RC + 9820 μL n-butyl acetate

[0081] Experiment 1

[0082] * The coating formulation (B17-66) was prepared by mixing the following two solutions:

[0083] A: 2000 μL D1500 RC + 1000 μL TG4

[0084] B: 2000 μL B17 POSS + 660 μL TBAF + 250 μL THF

[0085] The two solutions were mixed using a vortex, left to stand for 5 minutes, and then ultrasonic spray coating was performed.

[0086] * The formulation was applied to a glass slide substrate using an ultrasonic spray coater according to the following parameters: flow rate 0.8 mL / min, speed 25 mm / s, line spacing 10 mm, air pressure 0.45 bar, height 50 mm, and operating output 36%.

[0087] * After drying, the coating was cured by exposing it to H2O2 steam for 10 minutes in an oven maintained at 70°C, and then heated in an oven at 120°C for 1 hour.

[0088] * The drying conditions and the curing levels achieved accordingly are shown in Table 1, and drying at 55°C for the same drying time showed a better level of curing than drying at 70°C, and drying at 70°C showed a better level of curing than drying at 100°C.

[0089] * The average thickness of the cured coating was 8.5 μm.

[0090] When dried at 55°C for 30 minutes, the level of curing was approximately the same or similar as when dried at 100°C for 10 minutes. This suggests that a short drying time is advantageous for enhanced curing even at low drying temperatures.

[0091] Sample Drying temperature (°C) Drying time (minutes) FT-IR curing grade 1 55 10 2.25 2 70 10 3 3 100 10 3.75

[0092] Experiment 2

[0093] The coating formulation (A85-8) was prepared by mixing the following two solutions:

[0094] A: 1182 μL D1500 RC + 590 μL TG4

[0095] B: 1182 μL A85 POSS + 400 μL TBAF + 2250 μL THF

[0096] The two solutions were mixed using a vortex, left to stand for 5 minutes, and then ultrasonic spray coating was performed.

[0097] The prepared formulation was applied to a glass slide substrate using an ultrasonic spray coater according to the following parameters: flow rate 0.8 mL / min, speed 25 mm / s, line spacing 10 mm, air pressure 0.45 bar, height 50 mm, and operating output 36%.

[0098] After drying, the coating was cured by exposing it to a high-humidity atmosphere containing H2O2 vapor at 70°C for 10 minutes, and then heated in an oven at 120°C for 1 hour.

[0099] The drying conditions and the curing levels achieved accordingly are shown in Table 2, and drying at 55°C for 2 minutes showed a better level of curing than drying at the same temperature for 10 minutes and drying at 100°C for 10 minutes.

[0100] The average thickness of the cured coating was 3.7 μm.

[0101] Sample Drying temperature (°C) Drying time (minutes) FT-IR curing grade 1 55 2 1.75 2 55 10 3 3 100 10 4

[0102] Experiment 3

[0103] * Two solutions were prepared:

[0104] A: 200 μL D1500 RC + 100 μL TG4 + 700 μL THF

[0105] B: 100 μL A85 POSS + 32 μL TBAF + 868 μL THF

[0106] * The coating formulation was applied to a glass slide substrate using an ultrasonic spray coater as follows:

[0107] o First, Part B was injected: flow rate 0.4 mL / min, speed 25 mm / s, line spacing 10 mm, air pressure 0.45 bar, height 50 mm and operating output 36%.

[0108] o After 4 to 5 minutes, Part A was sprayed with the same parameters.

[0109] * After drying, the coating was cured by exposing it to a high-humidity atmosphere containing H2O2 vapor at 70°C for 10 minutes, and then heated in an oven at 120°C for 1 hour.

[0110] * The average thickness of the cured coating was 2.3 to 2.5 μm.

[0111] * The samples were dried at 70°C for 30, 60, and 80 seconds. The achieved curing levels were similar, ranging from 1.25 to 1.5. This indicates that sufficient drying of the coating for the curing process can be achieved by exposing it to hot air for only a short period of time.

[0112] Experiment 4

[0113] * Coating Formula (PP-1): 3940 μL PP + 3940 μL butyl acetate

[0114] * The formulation was applied to a glass slide substrate using an ultrasonic spray coater as follows: flow rate 0.8 mL / min, speed 35 mm / s, line spacing 7 mm, air pressure 0.45 bar, height 50 mm, and operating output 36%.

[0115] * After drying, the coating was cured by exposing it to a high-humidity atmosphere containing H2O2 vapor at 70°C for 10 minutes, and then heated in an oven at 120°C for 1 hour.

[0116] * The average thickness of the cured coating was 4 to 4.5 μm.

[0117] * The drying conditions and the curing levels achieved accordingly are shown in Table 3. Drying at 60°C for 5 minutes resulted in a slightly better curing level than drying at 115°C for 5 minutes, and both methods showed significantly better curing levels than drying at 160°C for 5 minutes. Sample 2, dried at 70°C for 1.5 minutes, showed a better curing level than drying at 60°C for 5 minutes, suggesting that even when using solvents with high boiling points, performing low-temperature drying for a short time of less than 5 minutes is sufficient to prepare the coating for curing.

[0118] Sample Drying temperature (°C) Drying time (minutes) FT-IR curing grade 1 60 5 1.75-2 2 70 1.5 1.25-1.5 3 115 5 2.5 4 160 5 4

[0119] Experiment 5

[0120] * Coating Formula (PP-1): 3940 μL PP + 3940 μL butyl acetate

[0121] * The coating formulation was applied to a glass slide substrate using an ultrasonic spray coater as follows: flow rate 0.8 mL / min, speed 35 mm / s, line spacing 7 mm, air pressure 0.45 bar, height 50 mm, and operating output 36%.

[0122] * After drying, the coating was cured by exposing it to a high-humidity atmosphere containing H2O2 vapor at 70°C for 10 minutes, and then heated in an oven at 120°C for 1 hour. The concentration of liquid H2O2 in the ultrasonic humidifier was varied from 20 wt% to 2.5 wt%.

[0123] * The average thickness of the cured coating was about 4.5 μm.

[0124] * The drying and curing conditions and the curing levels achieved accordingly are shown in Table 4. As a result, the curing level achieved under conditions with a low H2O2 concentration of 5% ranged from fair to good.

[0125] Sample Drying temperature (°C) Drying time (minutes) H 2 O 2 density (H 2 wt% of O FT-IR curing grade 1 70 1.5 20 1.25-1.5 2 70 1.5 10 1.5-2 3 70 1.5 5 2.25-3 4 70 1.5 2.5 4.25-4.5

[0126] Experiment 6

[0127] * Two coating formulations were prepared:

[0128] o B17-80 (Mix Part A and Part B by vortexing for 5 minutes)

[0129] A: 1182 μL D1500 RC + 590 μL TG4

[0130] B: 1420 μL B17 POSS + 400 μL TBAF + 2318 μL THF

[0131] o D1500-R2

[0132] 2000 μL D1500RC + 3910 μL THF

[0133] * The formulation was applied to a glass slide substrate using an ultrasonic spray coater as follows: flow rate 0.3 mL / min, line spacing 7 mm, air pressure 0.45 bar, height 50 mm, and operating power 36%. The speeds of B17-80 and D1500-R2 were 50 mm / s and 40 mm / s, respectively. B17-80 was applied in two layers, i.e., sprayed twice, while D1500-R2 was applied in a single layer.

[0134] * After drying at 70°C for 1.5 minutes, the coating was cured by exposing it to a high-humidity atmosphere containing H2O2 vapor at 70°C for 1.5 minutes. Afterward, the coating was heated for a specific period of time.

[0135] * The average thickness of the cured coating was about 3 μm.

[0136] * The conditions after H2O2 treatment are shown in Table 5, and the results are as follows:

[0137] 1) In the case of B17-80, heating at 120°C for 10, 30, and 60 minutes did not show a significant change in the level of curing. On the other hand, in the case of D1500-R2, heating for 30 and 60 minutes at the same temperature showed a slightly better level of curing than heating for 10 minutes. However, heating for 10 minutes also showed a good to very good level of curing. This indicates that a heating time of 10 minutes or less after H2O2 treatment, or heating at a lower temperature, is sufficient to achieve good curing.

[0138] 2) When heating was not performed after H2O2 treatment, the hardening level of B17-80 was moderate to good, whereas the hardening level of D1500-R2 was poor to very poor. As described in International Publication No. WO2023 / 282768 A1, the presence of TBAF, a quaternary ammonium salt (QAS), in B17-80 improved the hardening of B17-80, whereas in D1500-R2, due to the absence of TBAF, limited hardening was exhibited without additional heating treatment after H2O2 treatment.

[0139] combination H 2 O 2 After processing Heating temperature (°C) H 2 O 2 After processing Heating time (minutes) FT-IR curing grade D1500-R2 B17-80 1 120 10 1.75-2 2 120 30 1.75 3 120 60 2 4 doesn't exist N / A 2.5-3 1 120 10 2-2.5 2 120 30 1.5-1.75 3 120 60 1.75 4 doesn't exist N / A 5.25-6

[0140] As can be confirmed from the experiments above, the curing method according to the present invention demonstrates that a coating formulation deposited in a layer form on a substrate can be excellently cured even at low temperatures and within a short curing time.

Claims

Claim 1 A method for curing a layer deposited on a substrate, wherein the layer comprises a coating formulation containing hydrolyzable Si-X groups, wherein X is selected from halogen, C1-C6 alkoxy, hydrogen, -NH-Si, or -NH2, and the coating formulation is dissolved in a solvent, and the method comprises the following steps: a) drying the layer at a temperature not exceeding 20°C above the boiling point of the solvent; and b) exposing the layer to curing vapor. Claim 2 A method according to claim 1, wherein steps a) and b) are performed simultaneously. Claim 3 A method according to claim 1 or 2, wherein the hardening steam comprises one or more of water, H2O2, NH3, organic acids and inorganic acids. Claim 4 A method in which, in any one preceding claim, the hardening steam comprises 1 to 30 wt% of H2O2 in water. Claim 5 A method in which, in any one preceding claim, the drying is performed at a temperature not exceeding 10°C above the boiling point of the solvent. Claim 6 A method in which, in any preceding claim, step a) is performed within a time of 20 to 30 minutes or less. Claim 7 A method wherein, in any one preceding claim, step a) is performed for 10 seconds to 30 minutes, preferably for 30 seconds to 5 minutes. Claim 8 A method in which, in any one preceding claim, the layer is exposed to curing steam, and then heated to a temperature above the boiling point of the solvent. Claim 9 A method according to claim 8, wherein the temperature is less than 200℃ and the heating time is 60 minutes or less. Claim 10 In any preceding claim, X is selected from chlorine, bromine, methoxy, ethoxy, hydrogen, NH-Si, or NH2, method. Claim 11 A method in which, in any one of the preceding claims, the solvent is selected from tetrahydrofuran (THF), 2-methyltetrahydrofuran (MTHF), n-butyl acetate, tert-butyl acetate, or dibutyl ether (DBE). Claim 12 A substrate manufactured using a method according to any preceding claim.

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