Ultrathin glass protective coating and flexible electronic product glass containing same

Abstract

The invention provides an ultra-thin glass UTG (Untranslated Glass) protective coating and flexible electronic product glass containing the protective coating. The protective coating comprises a network polymer with the following structural formula (I), the network polymer is provided with a plurality of acrylate modified polyurethane chains and a plurality of carbon chains, the acrylate modified polyurethane chains and the carbon chains are alternately connected to form a network, the carbon chains are straight chains or branched chains, and the lengths of the carbon chains are the same or different. According to the protective coating, the impact resistance of the ultrathin glass can be improved by more than 200%, and the ultrathin glass has excellent visible light transmittance (greater than or equal to 91.5%), low haze (less than 1%), high pencil hardness (greater than 2H) and good adhesive force and wear resistance. In the structural formula (I), m is an integer from 1 to 10000, and each group is defined in the specification.

Description

Technical Field

[0001] The present invention relates to the field of flexible display technology, and specifically to a coating, an ultra-thin glass (UTG) protective coating prepared using the coating, a preparation method thereof, and glass for flexible electronic products containing the coating. The coating is particularly suitable for fields such as foldable screen mobile phones, tablet computers, and wearable devices that require high impact resistance, high light transmittance, and dynamic bending performance. Background Art

[0002] UTG (Ultra-Thin Glass) is a high-performance glass material typically less than 0.1 mm thick, combining the high hardness and scratch resistance of traditional glass with excellent flexibility. Through specialized processing, UTG can be bent multiple times without breaking, making it widely used in flexible electronic products such as foldable phones, tablets, and wearable devices. Its outstanding mechanical strength and optical properties not only enhance device durability and tactile feel, but also enable slimmer, more advanced designs, making it a key material for next-generation smart devices.

[0003] UTG (ultra-thin glass) is extremely thin and has poor inherent impact resistance. Therefore, it is easy to break or be damaged when subjected to external force. In order to improve its impact resistance, technicians have tried to add special coatings to the surface. In order to increase the hardness, wear resistance and impact resistance of existing UTG (ultra-thin flexible glass), it is usually necessary to add multiple coatings on the surface for protection. For example, a hard coating and a special protective film are added on top of the UTG, and a protective film or cushioning layer (such as PET) may also be added underneath. Although this multi-layer protective structure improves the protection ability of UTG, it also increases the thickness, resulting in complex processes, increased costs, and may affect flexibility and bending properties. If a material that can provide good protection with a single coating is developed, it will simplify the production process, reduce costs, keep the product light and thin, and at the same time improve the service life and reliability of UTG.

[0004] Chinese patent application publication number CN119391290A discloses a high-impact coating for ultra-thin glass, which is mainly prepared by UV curing under solvent-free conditions using a precursor, a cross-linking agent, and a photoinitiator. Although the high-impact coating is a single coating and exhibits good adhesion and optical properties, its hardness, wear resistance, bending resistance, and especially impact resistance are difficult to meet the requirements.

[0005] The UTG coating also needs to have a certain degree of flexibility to effectively enhance the toughness of the glass and disperse impact energy, thereby improving the durability and reliability of the UTG. The UTG coating also needs to have excellent optical transmittance and low haze, good adhesion to UTG glass, and excellent wear resistance and hardness requirements to meet the requirements of use in high-intensity application scenarios.

[0006] However, there is currently no effective coating that can simultaneously meet these requirements and provide good protection for UTG. Summary of the Invention

[0007] In order to solve the problems of poor impact resistance, complex multi-layer protection structure, insufficient light transmittance and bending failure caused by the ultra-thinness of UTG, we have developed a coating technology for UTG. This technology combines polyurethane with acrylates, silanes (also referred to as silicones in this article), epoxy compounds, etc., and combines the advantages of various materials to prepare a coating with excellent comprehensive performance. The prepared coating has good wear resistance and bending properties. In terms of component design, polyurethane is generated by the reaction of polyether polyols and polyisocyanates, providing flexibility to disperse impact stress; acrylates can enhance the hardness and light transmittance of the coating; silanes contain silicon oxygen functional groups to improve the interfacial adhesion with the UTG matrix; epoxy compounds can improve wear resistance and structural stability through epoxy group cross-linking. In terms of process design, it includes step-by-step synthesis (prepolymer preparation → acrylate modification → coating preparation) and dual-curing process: thermal curing (80-120°C) combined with UV curing (20-100mW / cm 2 ), forming a high-crosslinked, three-dimensional network structure. Applying a UTG coating to UTG glass can improve the impact resistance of UTG glass by over 200% without affecting the properties of the UTG itself, providing excellent protection for UTG glass and enabling it to meet the various requirements of flexible screens.

[0008] Specifically, the present application provides a coating comprising the following components in parts by mass:

[0009] 100 parts of acrylate modified polyurethane resin;

[0010] 10-80 parts of one or more acrylates, or a combination of one or more acrylates and acrylic acid;

[0011] 0.5-10 parts of one or more silanes with double bond functional groups;

[0012] 1-10 parts of one or more epoxy compounds with double bond functional groups;

[0013] The acrylate-modified polyurethane resin has the following chemical structural formula:

[0014]

[0015] in:

[0016] R1 is

[0017] n is an integer from 10 to 2000;

[0018] R2 is

[0019] R3 is C 1-4 Alkylene.

[0020] In one embodiment, the coating of the present application further comprises one or more of a photoinitiator, a defoaming agent and a leveling agent.

[0021] In the coating of the present application, based on the total mass of the coating, the photoinitiator generally accounts for 0.1-5%, preferably 0.1-2.5%; the defoamer generally accounts for 0.01%-5.00%, preferably 0.01%-1.00%, more preferably 0.05%-0.5%; the leveling agent generally accounts for 0.02%-5.00%, preferably 0..02%-1.00%, more preferably 0.05%-0.5%.

[0022] Accordingly, the present application also provides a method for preparing the coating of the present application, comprising the following steps:

[0023] a) Preparation of polyurethane prepolymer

[0024] According to the following chemical reaction formula, polyether polyol and polyisocyanate are heated at 50-100° C. in a mass ratio of 100:10-100 for reaction for 1-5 hours to generate a prepolymer;

[0025]

[0026] Polyether polyols with structural formula Indicated by the structural formula Indicates that the generated prepolymer is Indicates that:

[0027] R1 is

[0028] n is an integer from 10 to 2000;

[0029] R2 is

[0030] b) Acrylate modification

[0031] According to the following chemical reaction formula, in a solvent, at a mass ratio of prepolymer: hydroxyalkyl acrylate: solvent of 100:1-50:10-200, the prepolymer and hydroxyalkyl acrylate are heated and reacted at 50-100°C for 1-5 hours to generate an acrylate-modified polyurethane resin:

[0032]

[0033] Hydroxyalkyl acrylate Indicates that acrylate modified polyurethane resin is used Indicates that:

[0034] R3 is C 1-4 alkylene;

[0035] c) Paint preparation

[0036] Under stirring, the prepared acrylate-modified polyurethane resin, one or more acrylates, or a combination of one or more acrylates and acrylic acid, one or more silanes with double bond functional groups, and one or more epoxy compounds with double bond functional groups are mixed until uniform to obtain a clear coating solution.

[0037] Preferably, the reaction temperature of the acrylate modification step b) is not higher than the reaction temperature of the polyurethane prepolymer preparation step a).

[0038] According to the preparation method of the coating of the present application, the hydroxyalkyl acrylate used in the acrylate modification step b) is preferably hydroxyalkyl acrylate. 1-4 The alkyl ester is, for example but not limited to, one or more of hydroxymethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxybutyl acrylate, and the solvent used is one or more of dioxane, dimethyl carbonate, propylene glycol methyl ether propionate, ethyl acetate, butyl acetate, toluene, acetone, dimethylformamide, and methyl pyrrolidone.

[0039] In one embodiment, in the coating preparation step c), the mass ratio of acrylate-modified polyurethane resin, acrylate or combination of acrylate and acrylic acid, silane, and epoxy compound is 100:10-80:0.5-10:1-10, preferably 100:10-50:0.5-5:1-5.

[0040] In a preferred embodiment, one or more of a photoinitiator, a defoamer, and a leveling agent may be further added in the coating preparation step c) of the coating preparation method of the present application. The amount of the photoinitiator added is 0.1%-5% of the total mass of the protective coating solution, preferably 0.1%-2.5%; the amount of the defoamer added is 0.01%-5.00% of the total mass of the protective coating solution, preferably 0.01%-1.00%, more preferably 0.05%-0.5%; the amount of the leveling agent added is 0.02%-5.00% of the total mass of the protective coating solution, preferably 0.02%-1.00%, more preferably 0.05%-0.5%.

[0041] On the other hand, the present application also provides an ultra-thin glass protective coating, comprising a network polymer having the following structural formula (I), wherein the network polymer has a plurality of acrylate-modified polyurethane chains and a plurality of carbon chains, wherein the acrylate-modified polyurethane chains and the carbon chains are alternately connected to form a network, and the plurality of carbon chains are linear or branched, and their lengths are the same or different:

[0042]

[0043] in:

[0044] R1 is

[0045] n is an integer from 10 to 2000;

[0046] R2 is

[0047] R3 is C 1-4 alkylene;

[0048] R4 is a polyacrylate, connected to the carbon chain of the network polymer, and the number is one or more. When the number is more than one, each R4 is the same or different;

[0049] R5 is a polysilane compound connected to the carbon chain of the network polymer, and the number is one or more. When the number is more than one, each R5 is the same or different;

[0050] R6 is a polyepoxy acrylate compound connected to the carbon chain of the network polymer, and the number is one or more. When the number is more than one, each R6 is the same or different;

[0051] m is an integer of 1 to 10,000, preferably 10 to 10,000, more preferably 50 to 5,000, and even more preferably 50 to 2,500.

[0052] In one embodiment, in the network polymer of formula (I) contained in the ultra-thin glass protective coating of the present application, R4 is independently

[0053]

[0054] R5 is independent

[0055]

[0056] R6 is independent

[0057]

[0058] m4 is an integer from 1 to 10000;

[0059] M5 is an integer from 1 to 10000;

[0060] M6 is an integer from 1 to 10,000; and

[0061] The sum of m4+M5+M6 is less than m.

[0062] According to the present application, the polyacrylate of R4 includes but is not limited to one or more of polymethyl acrylate, polyhydroxyethyl acrylate, polybutyl acrylate, polyhydroxybutyl acrylate, polytrimethylolpropane triacrylate, polypentaerythritol triacrylate, polypentaerythritol tetraacrylate, polybornyl acrylate and polylauryl acrylate, the polysilane compound of R5 includes but is not limited to one or more of polyvinyl triethoxysilane, polypropylene triethoxysilane and polyacryloxypropyl triethoxysilane, and the polyepoxy acrylate compound of R6 includes but is not limited to one or more of polyglycidyl acrylate and polyoxyethylene methoxybutyl acrylate.

[0063] In the infrared spectrum of the protective coating of the present application, the peak position is 3300-3500 cm -1 Range and 1750cm -1 There is a characteristic absorption peak of carbamate near the peak position of 1000-1200cm -1 There is a characteristic absorption peak of silicon-oxygen bond in the range of 900-950cm -1 There is a characteristic absorption peak of epoxy group in the range.

[0064] The protective coating of the present application can improve the impact resistance of ultra-thin glass by more than 200%.

[0065] In one embodiment, the protective coating of the present application further has at least one of the following characteristics, preferably has the following three characteristics:

[0066] i) Visible light transmittance is above 91.5%;

[0067] ii) haze less than 1%, preferably 0.25-0.8%;

[0068] iii) Pencil hardness greater than 2H.

[0069] In one embodiment, the protective coating further comprises a defoaming agent and a leveling agent.

[0070] In some cases, the ultra-thin glass protective coating of the present application may also contain residual solvents, such as but not limited to one or more of dioxane, dimethyl carbonate, propylene glycol methyl ether propionate, ethyl acetate, butyl acetate, toluene, acetone, dimethylformamide, and methyl pyrrolidone.

[0071] Correspondingly, the present application also provides a method for preparing the protective coating of the present application, wherein the protective coating includes a network polymer formed by cross-linking an acrylate-modified polyurethane resin, acrylate or a combination of acrylate and acrylic acid, a silane with a double bond functional group, and an epoxy compound with a double bond functional group.

[0072] Specifically, the present application provides a method for preparing an ultra-thin glass protective coating, wherein the protective coating comprises a network polymer having the following structural formula (I), and the method comprises the following steps:

[0073] 1) Coating and heating curing

[0074] Apply the coating of the present application or the coating prepared in the present application to the UTG surface, and heat and cure at 80-120° C. for 0.5-4 hours to remove the solvent;

[0075] 2) UV curing

[0076] After the heat curing is completed, 20-100mW / cm 2 The protective coating is obtained by subjecting the coating to UV irradiation for 1 to 5 minutes at an irradiation intensity of 100 nm to form a network polymer, thereby forming the protective coating.

[0077]

[0078] in:

[0079] The definitions of R1, R2 and R3 are the same as those of the acrylate-modified polyurethane resin described in this application;

[0080] R4 is a polyacrylate, R5 is a polysilane compound, and R6 is a polyepoxy acrylate compound;

[0081] R4, R5 and R6 are respectively connected to the carbon chain formed by the double bond of the acrylate-modified polyurethane resin, the double bond of the acrylate or the combination of acrylate and acrylic acid, the double bond of the silane with a double bond functional group and the double bond of the epoxy compound with a double bond functional group;

[0082] The number of R4 is one or more, and when the number is more than one, each R4 is the same or different;

[0083] The number of R5 is one or more. When the number is more than one, each R5 is the same or different;

[0084] The number of R6 is one or more, and when the number is more than one, each R6 is the same or different;

[0085] m is an integer from 1 to 10,000.

[0086] According to the above method, the double bonds of the various components in the coating—namely, the acrylate-modified polyurethane resin, the acrylate or a combination of acrylate and acrylic acid, the silane with double bond functional groups, and the epoxy compound with double bond functional groups—react under UV irradiation, forming carbon chains of a network polymer. The backbone portions of the acrylate-modified polyurethane resin without double bonds form the acrylate-modified polyurethane chains of the network polymer, and the acrylate-modified polyurethane chains and carbon chains are alternately connected to form a network structure. The remaining portions of the acrylate or a combination of acrylate and acrylic acid, the silane with double bond functional groups, and the epoxy compound with double bond functional groups without double bonds are connected to the carbon chains, with the connection positions being those carbon atoms that had double bonds before the reaction of the components.

[0087] The network polymer of the present application may have multiple acrylate-modified polyurethane chains and multiple carbon chains. Since the types and quantities of the components in the coating, such as acrylate or a combination of acrylate and acrylic acid, silane with double bond functional groups, and epoxy compounds with double bond functional groups, may be different, the lengths of the carbon chains formed by the double bonds of these components may be the same or different, and the carbon chains may be straight or branched.

[0088] Preferably, in the coating and heat curing step 1) of the above method, the coating is applied to the UTG surface by spraying or knife coating.

[0089] In the coating and heat curing step 1) of the above method, the main purpose of heating is to remove some or all of the solvent. In addition, some UTG glass surfaces contain hydroxyl groups. As shown below, heating can also cause the silane to react with these surface hydroxyl groups of the glass:

[0090]

[0091] By reacting silane with the hydroxyl groups on the surface of the glass, the protective coating of the present application can be firmly bonded to the surface of the UTG glass.

[0092] Therefore, in one embodiment, in step 1) of the method for preparing the protective coating of the present application, after heating and curing, the protective coating and the ultra-thin glass substrate are bonded together through Si—O bonds.

[0093] According to the preparation method of the protective coating of the present application, in the UV curing step 2), the irradiation intensity of the UV light used for UV curing is generally 20 to 100 mW / cm 2 , preferably 10-50mW / cm 2 .

[0094] On the other hand, the present application provides glass for flexible electronic products, which includes an ultra-thin glass substrate and a protective coating of the present application or a protective coating prepared by the protective coating preparation method of the present application, and the coating is applied to one or both sides of the ultra-thin glass substrate.

[0095] In a preferred embodiment, the protective coating of the glass for flexible electronic products of the present application is bonded to the ultra-thin glass substrate via Si—O bonds.

[0096] The thickness of the protective coating on the glass for flexible electronic products of the present application is generally 5 to 100 μm, preferably 10 to 50 μm.

[0097] In a preferred embodiment, the protective coating of the glass for flexible electronic products of the present application has a visible light transmittance of more than 91.5%, a haze of between 0.25 and 0.8, and a pencil hardness greater than 2H.

[0098] In one embodiment, in the glass for flexible electronic products of the present application, the coating is applied to one side of the ultra-thin glass substrate, and the other side of the ultra-thin glass substrate is coated with an optically clear adhesive (OCA) layer.

[0099] On the other hand, the present application provides a flexible electronic product, such as a foldable screen mobile phone, a tablet computer, a wearable device, etc. Such a flexible electronic product includes the glass for flexible electronic products of the present application.

[0100] In this application, the term "C 1-4 "Alkylene" includes methylene, ethylene, propylene, isopropylene, n-butylene, isobutylene and sec-butylene. The term "C 2-4 "Alkenylene" includes vinylene, propenylene, butenylene and isobutenylene. The term "C 1-4 "Alkyleneoxy" means C 1-4 Alkyleneoxy.

[0101] The additives used in this application, such as defoamers and leveling agents, are commonly used additives on the market. For example, the defoamer can be one or more of BYK-024, BYK-025, BYK-034, and BYK-045, and the leveling agent can be one or more of BYK310, BYK320, BYK333, and BYK341.

[0102] The polyether polyol used in the present application has an average molecular weight of 1000-3000 and is selected from polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polycarbonate polyol and combinations thereof.

[0103] The polyisocyanate used in the present application is selected from hexamethylenemethane diisocyanate, isophorone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and combinations thereof.

[0104] The acrylate used in this application has a double bond functional group and a molecular weight of generally 50-1000, for example but not limited to the following acrylate substances and combinations thereof: methyl methacrylate, hydroxyethyl acrylate, butyl acrylate, hydroxybutyl acrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, bornyl acrylate, and lauryl acrylate.

[0105] The silane used in this application has a silicon-oxygen functional group and a double bond functional group, and has a molecular weight of generally 50-1000, such as but not limited to the following silane substances and combinations thereof: vinyl triethoxysilane, propylene triethoxysilane, and acryloxypropyl triethoxysilane.

[0106] The epoxy compound used in the present application has an epoxy functional group and a double bond functional group, and has a molecular weight of generally 50-1000, such as but not limited to the following epoxy compounds and combinations thereof: glycidyl acrylate, oxiranyl methoxybutyl acrylate.

[0107] The photoinitiator used in this application is selected from diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), dibenzoylphosphine oxide (651), 1-hydroxycyclohexylphenyl ketone (184), 2-hydroxy-2-methyl-1-phenylpropanone (1173), 2-hydroxy-4'-(2-hydroxyethoxy)-phenylpropanone (2959) and combinations thereof.

[0108] Compared with the prior art, the present invention has the following beneficial effects:

[0109] By combining four ingredients—polyurethane, acrylic, silicone, and epoxy—into a single reaction, a new coating material has been innovatively developed. This coating combines the unique advantages of each component: polyurethane provides excellent flexibility and impact resistance; acrylic enhances the coating's hardness, transmittance, and gloss retention; silicone imparts excellent high and low temperature resistance and adhesion to glass; and epoxy resin provides hardness and good abrasion resistance. Ultimately, this all-in-one coating not only exhibits excellent overall performance but also provides comprehensive and long-lasting protection for UTG glass, significantly enhancing its lifespan and reliability.

[0110] Specifically, the advantages of the coating prepared by the present invention are reflected in the following aspects:

[0111] Improved impact resistance: The single-layer protective coating has been carefully designed and optimized to form a uniform and dense protective film on the UTG surface, effectively dispersing and buffering external impact forces, and increasing the UTG's pen drop test breakage height from 20 cm to ≥50 cm (Examples 1-4).

[0112] Excellent performance: The coating has a visible light transmittance of ≥91.5% (only 87.8% in comparative example 1 without adding acrylate), a haze of <1%, and excellent chemical stability, wear resistance and hardness. It can maintain good protective effects for a long time in various complex environments, meeting the high reliability requirements of UTG in different application scenarios.

[0113] Simplified structure (thickness reduction): Compared with the traditional multi-layer coating structure, the single-layer protective coating reduces the number of coating layers, directly reducing the thickness of the overall structure. The single-layer coating replaces the multi-layer composite structure, the thickness is reduced to 5-100μm, and there is no delamination after 200,000 bends (Comparative Example 2 failed the bending test when no silane compound was added). This not only helps to maintain the light and thin characteristics of UTG, making it more advantageous in fields such as flexible displays, but also reduces the stress concentration problem that may be caused by the superposition of multiple layers of coating, and improves the flexibility and reliability of UTG.

[0114] Simple synthesis: The synthesis process of a single-layer UTG protective coating is relatively simple. By selecting suitable raw materials and simple reaction conditions, a coating material with excellent performance can be prepared, which reduces the technical difficulty and equipment requirements in the production process.

[0115] Simplified coating process: During the coating process, the single-layer protective coating has excellent leveling and wettability, allowing it to be evenly applied to the UTG surface, reducing defects and blemishes during the coating process. Furthermore, the coating process has relatively few operating steps and requires less technical skills from the operator, improving production efficiency and product quality.

[0116] Cost Savings: The simplified synthesis and application process of the single-layer protective coating reduces raw material usage, equipment investment, energy consumption, and labor costs during production. Furthermore, the simplified process reduces scrap and defective product rates, further reducing production costs and improving product competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0117] Figure 1 It is the infrared spectrum of the coating prepared in Example 1.

[0118] Figure 2 This is the infrared spectrum of the coating prepared in Example 1. DETAILED DESCRIPTION

[0119] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0120] The inventors of this application have unexpectedly discovered that polyurethane can be combined with acrylates, silanes, and epoxy compounds to produce a coating with excellent overall performance. To prepare this coating, a polyurethane prepolymer is first combined with a hydroxyalkyl acrylate to form an acrylate-modified polyurethane resin. This acrylate-modified polyurethane resin is further mixed with acrylates or a combination of acrylates and acrylic acid, silanes, and epoxy compounds to form a protective coating. This protective coating is a clear, water-like solution composed of a mixture of chain-like polymers and small molecules. The protective coating is then heat-cured and cured with UV light using a photoinitiator to form the coating. This coating is a transparent, smooth coating whose primary component is a network polymer formed by cross-linking the acrylate-modified polyurethane resin, acrylates, epoxy compounds, and silanes, typically with an average molecular weight greater than 100,000 (W). Because the primary component of the prepared coating is a network polymer formed by the combination of multiple components, the network polymers prepared in the following examples are also referred to as all-in-one coatings.

[0121] In order to eliminate bubbles in the coating and make the coating surface smoother and more uniform, a small amount of defoaming agent and / or leveling agent can be added to the protective coating.

[0122] Example 1

[0123] 100 g of polycarbonate diol with an average molecular weight of 2000 was mixed with 32 g of 4,4-dicyclohexylmethane diisocyanate, and the mixture was reacted at 75° C. for 3 h to obtain a polyurethane prepolymer;

[0124] 70 g of dioxane solvent and 12 g of hydroxyethyl acrylate were added to 100 g of polyurethane prepolymer, and the mixture was reacted at 65° C. for 4 h to obtain an acrylate-modified polyurethane resin. Testing showed that the Tg of the obtained acrylate-modified polyurethane resin was -56° C.

[0125] Take 100g of acrylate-modified polyurethane resin, add 12g of isobornyl acrylate, 6g of pentaerythritol tetraacrylate resin, 1.4g of acryloxypropyl triethoxysilane and 2g of oxiranyl methoxybutyl acrylate, stir and mix at room temperature for 30min, then add 2g of TPO photoinitiator, 0.15g of BYK-034 defoamer and 0.25g of BYK-341 leveling agent, stir and mix to obtain UTG glass protective coating;

[0126] At room temperature, the obtained UTG glass protective coating was sprayed onto one side of the UTG glass surface, and then placed in a 90°C oven for 2 hours, and then subjected to UV irradiation at 30 mW / cm 2 The UTG glass protective coating was cured after irradiation for 1.5 minutes at a dose of 1.5 μm. The UTG glass protective coating was a transparent smooth coating. The thickness of the UTG glass protective coating was measured to be 15 μm.

[0127] The chemical reaction formula involved in this embodiment is as follows:

[0128]

[0129] It was determined that the average molecular weight of the network polymer contained in the protective coating was 16W.

[0130] The infrared spectra of the coating and coating prepared in this embodiment are as follows: Figure 1 and Figure 2 As shown in the figure, we can see that:

[0131] Figure 1 Paint and Figure 2 The infrared spectrum of the coating has a peak at 3300-3500 cm -1 Range and 1750cm -1 There is a characteristic absorption peak of the carbamate group in polyurethane near the peak position of 1000-1200cm -1 The characteristic absorption peak of the silicon-oxygen bond in the silane is within the range of 900-950 cm -1 There is a characteristic absorption peak of epoxy group in the range. Figure 1 Paint at 1650cm -1 There is an infrared absorption peak of acrylate double bond near it. After curing to form a coating, Figure 2 Medium 1650cm -1 The nearby double bond peak disappears, indicating that the double bond reaction is complete and a polymer coating containing the network polymer is formed.

[0132] Example 2

[0133] 100 g of polypropylene glycol with an average molecular weight of 1000 was mixed with 35 g of hexamethylene diisocyanate and reacted at 90° C. for 2.5 h to obtain a polyurethane prepolymer;

[0134] 60 g of dimethyl carbonate solvent and 12 g of hydroxybutyl acrylate were added to 100 g of polyurethane prepolymer, and the mixture was reacted at 70° C. for 3.5 h to obtain an acrylate-modified polyurethane resin. Testing showed that the Tg of the obtained acrylate-modified polyurethane resin was -62° C.

[0135] Take 100g of acrylate-modified polyurethane resin, add 8g of butyl acrylate, 10g of pentaerythritol tetraacrylate, 1.2g of vinyl trimethoxysilane and 2g of glycidyl acrylate, stir at room temperature for 30min to mix evenly, then add 2.5g of 184 photoinitiator, 0.12g of BYK-025 defoamer and 0.2g of BYK-333 leveling agent, stir evenly to obtain UTG glass protective coating;

[0136] At room temperature, the UTG glass protective coating was sprayed onto one side of the UTG glass surface, heated in an oven at 80°C for 2 hours, and then irradiated with UV light at 40 mW / cm 2 The UTG glass protective coating is obtained by irradiating the glass with a dose of 2 minutes for curing, and the UTG glass protective coating is a transparent smooth coating. It is measured that the thickness of the UTG glass protective coating is 20 μm.

[0137] The chemical reaction formula involved in this embodiment is as follows:

[0138]

[0139] It was determined that the average molecular weight of the network polymer contained in the protective coating was 14W.

[0140] Example 3

[0141] 100 g of polypropylene glycol with an average molecular weight of 2000 was mixed with 40 g of isophorone diisocyanate and reacted at 80° C. for 3 h to obtain a polyurethane prepolymer;

[0142] 80 g of butyl acetate solvent and 10 g of hydroxyethyl acrylate were added to 100 g of polyurethane prepolymer, and the mixture was reacted at 80° C. for 3 h to obtain an acrylate-modified polyurethane resin. Testing showed that the Tg of the obtained acrylate-modified polyurethane resin was -54° C.

[0143] Take 100g of acrylate-modified polyurethane resin, add 10g of acrylic acid, 10g of trimethylolpropane triacrylate, 1g of methacryloyloxypropyl triethoxysilane and 1g of glycidyl acrylate, stir at room temperature for 30min to mix evenly, then add 2g of 1173 photoinitiator, 0.15g of BYK-024 defoamer and 0.15g of BYK-320 leveling agent, stir evenly to obtain UTG glass protective coating;

[0144] At room temperature, the obtained UTG glass protective coating was sprayed onto the UTG glass, and then placed in a 90 ° C oven for 2.5 h, and then irradiated with UV at 60 mW / cm 2 The UTG glass protective coating was cured after irradiation for 2 minutes at a dose of 100 μm and a transparent smooth coating was obtained. The thickness of the UTG glass protective coating was measured to be 25 μm.

[0145] The chemical reactions involved in this embodiment are as follows:

[0146]

[0147] It was determined that the average molecular weight of the network polymer contained in the protective coating was 15W.

[0148] Example 4

[0149] 100 g of polytetramethylene glycol with an average molecular weight of 1000 was mixed with 42 g of 4,4-dicyclohexylmethane diisocyanate, and the mixture was reacted at 85° C. for 2.5 h to obtain a polyurethane prepolymer;

[0150] 60 g of propylene glycol methyl ether propionate solvent and 12 g of hydroxyethyl acrylate were added to 100 g of polyurethane prepolymer, and the mixture was reacted at 60° C. for 3.5 h to obtain an acrylate-modified polyurethane resin. The obtained acrylate-modified polyurethane resin had a Tg of -57° C. after testing.

[0151] Take 100g of acrylate-modified polyurethane resin, add 10g of butyl acrylate, 6g of pentaerythritol tetraacrylate, 1.1g of vinyl triethoxysilane and 2.2g of glycidyl acrylate, stir for 30min to mix evenly, then add 2.4g of 2959 photoinitiator, 0.1g of BYK-033 defoamer, 0.2g of BYK-341 leveling agent, stir evenly to obtain UTG glass protective coating;

[0152] At room temperature, the obtained UTG glass protective coating was scraped onto the UTG glass, and then placed in an oven at 100°C for 1.5 hours, and then subjected to UV irradiation at 50 mW / cm 2 The UTG glass protective coating was cured after irradiation for 1 minute at a dose of 100 μm. The UTG glass protective coating was a transparent smooth coating. The thickness of the UTG glass protective coating was measured to be 20 μm.

[0153] The chemical reaction formula involved in this embodiment is as follows:

[0154]

[0155] It was determined that the average molecular weight of the network polymer contained in the protective coating was 18W.

[0156] Comparative Example 1

[0157] 100 g of polypropylene glycol with an average molecular weight of 2000 was mixed with 40 g of isophorone diisocyanate and reacted at 80° C. for 3 h to obtain a polyurethane prepolymer;

[0158] 80 g of butyl acetate solvent and 10 g of hydroxyethyl acrylate were added to 100 g of polyurethane prepolymer, and the mixture was reacted at 80° C. for 3 h to obtain an acrylate-modified polyurethane resin. Testing showed that the Tg of the obtained acrylate-modified polyurethane resin was -52° C.

[0159] Take 100g of acrylate-modified polyurethane resin, add 1g of acryloxypropyl triethoxysilane and 1g of oxiranyl methoxybutyl acrylate, stir at room temperature for 30min to mix evenly, then add 1.5g of 1173 photoinitiator, 0.15g of BYK-025 defoamer, and 0.2g of BYK-320 leveling agent, stir evenly to obtain UTG glass protective coating;

[0160] At room temperature, the obtained UTG glass protective coating was sprayed onto one side surface of the UTG glass, and then placed in a 90°C oven for heating for 2.5 hours, and then subjected to UV irradiation at 70 mW / cm 2 The UTG glass protective coating was cured after irradiation for 2.5 minutes at a dose of 100 μm and obtained as a transparent smooth coating. The thickness of the UTG glass protective coating was measured to be 20 μm.

[0161] The chemical reaction formula involved in this embodiment is as follows:

[0162]

[0163] It was determined that the average molecular weight of the network polymer contained in the protective coating was 15W.

[0164] Comparative Example 2

[0165] 100 g of polypropylene glycol with an average molecular weight of 2000 was mixed with 45 g of hexamethylene diisocyanate and reacted at 85° C. for 2 h to obtain a polyurethane prepolymer;

[0166] 50 g of dimethyl carbonate solvent and 10 g of hydroxyethyl acrylate were added to 100 g of polyurethane prepolymer, and the mixture was reacted at 80° C. for 2.5 h to obtain an acrylate-modified polyurethane resin. The obtained acrylate-modified polyurethane resin had a Tg of -57° C. after testing.

[0167] Take 100g of acrylate-modified polyurethane resin, add 12g of isobornyl acrylate, 10g of pentaerythritol tetraacrylate, and 2g of glycidyl acrylate, stir for 30min to mix evenly, then add 2.5g of 184 photoinitiator, 0.12g of BYK-024 defoamer, and 0.2g of BYK-333 leveling agent, stir evenly to obtain UTG glass protective coating;

[0168] At room temperature, the obtained UTG glass protective coating was scraped onto one side of the UTG glass, and then placed in a 90°C oven for 2 hours, and then subjected to UV irradiation at 40 mW / cm 2 The UTG glass protective coating was cured after irradiation for 1.5 minutes at a dose of 1.5 μm. The UTG glass protective coating was a transparent smooth coating. The thickness of the UTG glass protective coating was measured to be 15 μm.

[0169] The chemical reaction formula involved in this embodiment is as follows:

[0170]

[0171] It was determined that the average molecular weight of the network polymer contained in the protective coating was 17W.

[0172] Comparative Example 3

[0173] 100 g of polycarbonate diol with an average molecular weight of 2000 was mixed with 35 g of 4,4-dicyclohexylmethane diisocyanate, and the mixture was reacted at 80° C. for 2.5 h to obtain a polyurethane prepolymer;

[0174] 75 g of dioxane solvent and 6 g of hydroxyethyl acrylate were added to 100 g of polyurethane prepolymer, and the mixture was reacted at 70° C. for 4 h to obtain an acrylate-modified polyurethane resin. Testing showed that the Tg of the obtained acrylate-modified polyurethane resin was −63° C.

[0175] Take 100g of acrylate-modified polyurethane resin, add 8g of isobornyl acrylate, 6g of pentaerythritol tetraacrylate, and 1.4g of acryloxypropyltriethoxysilane, stir for 30 minutes to mix evenly, then add 2g of TPO photoinitiator, 0.15g of BYK-034 defoamer, and 0.25g of BYK-333 leveling agent, stir evenly to obtain UTG glass protective coating;

[0176] At room temperature, the obtained UTG glass protective coating was sprayed onto one side surface of the UTG glass, and then placed in a 90°C oven for 2 hours, and then subjected to UV irradiation at 50 mW / cm 2 The UTG glass protective coating was cured after irradiation for 2 minutes at a dose of 100 μm and a transparent smooth coating was obtained. The thickness of the UTG glass protective coating was measured to be 25 μm.

[0177] The chemical reaction formula involved in this embodiment is as follows:

[0178]

[0179] It was determined that the average molecular weight of the network polymer contained in the protective coating was 15W.

[0180] Comparative Example 4

[0181] 100 g of polytetramethylene glycol with an average molecular weight of 2000 was mixed with 32 g of 4,4-dicyclohexylmethane diisocyanate, and the mixture was reacted at 80° C. for 3 h to obtain a polyurethane prepolymer;

[0182] 50 g of propylene glycol methyl ether propionate solvent and 10 g of hydroxyethyl acrylate were added to 100 g of polyurethane prepolymer, and the mixture was reacted at 70° C. for 3 h to obtain an acrylate-modified polyurethane resin. The obtained acrylate-modified polyurethane resin had a Tg of -55° C. after testing.

[0183] Take 100g of acrylate-modified polyurethane resin, add 10g of trimethylolpropane triacrylate, 10g of isobornyl acrylate, 2.4g of 2959 photoinitiator, 0.1g of BYK-033 defoamer, and 0.2g of BYK-341 leveling agent, and stir evenly to obtain a UTG glass protective coating;

[0184] At room temperature, the obtained UTG glass protective coating was scraped onto one side of the UTG glass, and then placed in an oven at 100°C for 1.5 hours, and then irradiated with UV light at 30 mW / cm 2 The UTG glass protective coating was cured after irradiation for 1 minute at a dose of 100 μm. The UTG glass protective coating was a transparent smooth coating. The thickness of the UTG glass protective coating was measured to be 20 μm.

[0185] The chemical reaction formula involved in this embodiment is as follows:

[0186]

[0187] Performance Testing

[0188] The coatings prepared in Examples 1-4 and Comparative Examples 1-4 were tested for performance according to the following standards.

[0189] Adhesion test: GB / T 1720-1989

[0190] Boiling adhesion test: GB / T 9286-98

[0191] Pencil hardness: GB / T 6739-1996

[0192] Light transmittance: GB / T 2410-2008

[0193] Haze: GB / T 2410-2008

[0194] Wear resistance: GB / T 1768-1993

[0195] Impact resistance: A 15g ballpoint pen was dropped vertically onto UTG glass (156mm long, 71mm wide, 0.03mm thick) to test its impact resistance. The height at which the glass shattered was observed. Ordinary UTG glass shattered at a height of approximately 20cm.

[0196] Bending test: The UTG glass with protective coating prepared in each embodiment and comparative example was used as a sample and installed in a dynamic folding device with two folding stages at room temperature. The folding stage was rotated from 180° (flat state) to 0° (folded state) and subjected to 200,000 cycles at a bending distance of 40 mm and a rate of 30 cycles / min. The bending curvature diameter of 3 mm was determined by the gap between the two rigid plates in the closed state (0°), and no mandrel was used to guide the curvature. After 200,000 cycles, the sample was removed from the dynamic folding device for observation. If no buckling or delamination of the composite structure was observed, the observed sample passed the dynamic folding test.

[0197] The test results are as follows:

[0198]

[0199]

[0200] Examples 1-4 respectively use different diols (polypropylene glycol, polyoxypropylene ether, polycarbonate diol and polytetramethylene glycol) to prepare polyurethane, which is then combined with acrylate (or a combination of acrylate and acrylic acid), silane and epoxy compound to prepare UTG protective coating. The results show that the properties of the prepared coatings are slightly different, but all meet the standards.

[0201] Comparative Example 1, in which the amount of acrylate added was reduced, showed a slight decrease in hardness and optical quality. Comparative Example 2, in which no silane was added, exhibited poor adhesion to glass, easily falling off after boiling in water, and also easily separating from the glass during a folding test. Comparative Example 3, in which no epoxy compound was added, showed a decrease in hardness and poorer abrasion resistance. Comparative Example 4, in which neither silane nor epoxy compound was added, exhibited poor adhesion, boiling in water, hardness, abrasion resistance, and flexural properties.

[0202] The coatings of Examples 1-4 can effectively improve the impact resistance of UTG glass, from 20 cm to more than 50 cm, with the impact resistance improved by more than 200%. This shows that the coating prepared by the present invention can effectively protect UTG glass and enable it to meet the application requirements in flexible screens.

[0203] 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 and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An ultra-thin glass protective coating, characterized in that: The protective coating comprises a network polymer having the following structural formula (I), wherein the network polymer comprises a plurality of acrylate-modified polyurethane chains and a plurality of carbon chains, wherein the acrylate-modified polyurethane chains and the carbon chains are alternately connected to form a network, and the plurality of carbon chains are linear or branched, and have the same or different lengths: in: R1 is n is an integer from 10 to 2000; R2 is R3 is C 1-4 alkylene; R4 is a polyacrylate, connected to the carbon chain of the network polymer, and the number is one or more. When the number is more than one, each R4 is the same or different; R5 is a polysilane compound connected to the carbon chain of the network polymer, and the number is one or more. When the number is more than one, each R5 is the same or different; R6 is a polyepoxy acrylate compound connected to the carbon chain of the network polymer, and the number is one or more. When the number is more than one, each R6 is the same or different; m is an integer from 1 to 10,000.

2. The protective coating according to claim 1, characterized in that R4 is independent R5 is independent R6 is independent m4 is an integer from 1 to 10000; M5 is an integer from 1 to 10000; M6 is an integer from 1 to 10,000; and The sum of m4+M5+M6 is less than m.

3. The protective coating according to claim 1 or 2, characterized in that In the infrared spectrum of the coating, the peak position is 3300-3500 cm -1 Range and 1750cm -1 There is a characteristic absorption peak of carbamate near the peak position of 1000-1200cm -1 There is a characteristic absorption peak of silicon-oxygen bond in the range of 900-950cm -1 There is a characteristic absorption peak of epoxy group in the range.

4. The protective coating according to claim 1 or 2, characterized in that The protective coating can improve the impact resistance of ultra-thin glass by more than 200%.

5. The protective coating according to claim 1 or 2, characterized in that: The protective coating has the following characteristics: i) Visible light transmittance is above 91.5%; ii) haze less than 1%; iii) Pencil hardness greater than 2H.

6. A glass for flexible electronic products, characterized in that: The invention comprises an ultra-thin glass substrate and the protective coating according to claim 1, wherein the coating is applied to one or both sides of the ultra-thin glass substrate.

7. The glass according to claim 6, characterized in that The thickness of the protective coating is 5 to 100 μm.

8. The glass according to claim 6, wherein The coating is coated on one side of the ultra-thin glass substrate, and the other side of the ultra-thin glass substrate is coated with an optically transparent adhesive layer.

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