Hydrofluoric acid-resistant composition, preparation method thereof, substrate and processing method thereof

Abstract

The invention discloses a hydrofluoric acid-resistant composition, a preparation method thereof, a substrate and a processing method of the substrate. The hydrofluoric acid-resistant composition comprises a polymer resin and an inorganic filler, the polymer resin comprises a structural resin, an adhesive resin and a binding force reinforcing resin, and the structural resin comprises a fluorine-containing polymer; the bonding resin comprises polyvinyl acetal resin; the binding force reinforcing resin includes an epoxy resin and a phenolic resin. By adopting a specific composition formula, excellent hydrofluoric acid resistance is realized, and the hydrofluoric acid can be dissolved and removed or physically removed (such as hand tearing, adhesive tape tearing and the like) in a mild alcohol solvent soaking manner after processing, so that the technical problem that ultrathin glass fragments are easily caused by physical tearing of a protective film is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of glass substrate processing, in particular to a hydrofluoric acid-resistant composition, a preparation method thereof, a substrate and a processing method thereof. BACKGROUND

[0002] In modern electronic device manufacturing, glass substrates, especially ultra-thin glass (UTG), are widely used due to their excellent optical and mechanical properties. The processing of ultra-thin glass (e.g., glass with a thickness of no more than 70 microns) typically involves high-precision cutting and edge treatment steps.

[0003] A common processing method is to first laser cut the glass substrate, but laser cutting is prone to produce micro-cracks and burrs on the glass edge. In order to eliminate these defects and improve the edge strength, a subsequent chemical etching process is required, especially using a hydrofluoric acid (HF) solution to trim the cutting edge.

[0004] In this processing flow, a temporary protective layer must be applied to the surface of the glass substrate to ensure that only the cutting edge is exposed to hydrofluoric acid, while the main surface of the substrate (such as the functional area) is not corroded. Existing protection technologies, such as the use of polymer adhesive tape, can provide some acid resistance, but the main removal method is mechanical peeling.

[0005] However, ultra-thin glass is extremely brittle, and the physical stress generated during mechanical peeling of the protective film can easily cause the glass substrate to crack and produce debris, thereby severely reducing production yield. In addition, other types of chemical protective films (such as traditional resists) may require the use of strong alkalis or solvents for removal, which also poses the risk of complex processes or damage to the substrate.

[0006] Therefore, there is an urgent need in the art for a new type of protective material that must meet two seemingly contradictory performance requirements: on the one hand, it must have sufficient chemical inertness and adhesion to effectively protect the substrate surface in a hydrofluoric acid solution; on the other hand, it must be easily and completely removed by a mild, non-mechanical method (such as solvent soaking at a mild temperature) after completing the protection task to avoid physical damage to the ultra-thin glass. SUMMARY

[0007] The main purpose of the present application is to provide a hydrofluoric acid-resistant composition to solve the technical problem of existing temporary protective materials that are prone to cause substrate cracking and low yield when applied to ultra-thin glass substrate processing.

[0008] To achieve the above purpose, the hydrofluoric acid-resistant composition provided by the present application comprises a high molecular resin and an inorganic filler, wherein,

[0009] The high molecular resin comprises:

[0010] The structural resin comprises a fluorine-containing polymer;

[0011] The bonding resin comprises a polyvinyl acetal resin; and

[0012] The binding force reinforcing resin comprises an epoxy resin and a phenol resin.

[0013] The surface of the inorganic filler is modified by one or more functional groups selected from the group consisting of aniline groups, alkyl groups, nitrogen-containing functional groups in main chains or branched chains, double bond-containing functional groups, and epoxy groups.

[0014] In an embodiment, the fluorine-containing polymer comprises polyvinylidene fluoride.

[0015] In an embodiment, the polyvinylidene fluoride has a molecular weight of 400,000 g / mol to 2,000,000 g / mol.

[0016] In an embodiment, the polyvinyl acetal resin comprises a polyvinyl butyral resin.

[0017] In an embodiment, the polyvinyl butyral resin has a molecular weight of 5 g / mol to 10,000 g / mol.

[0018] In an embodiment, in the polyvinyl butyral resin, the weight percentage of polyvinyl alcohol is 11% to 27%, and the weight percentage of polyvinyl acetate is 0% to 8%.

[0019] In an embodiment, in the polyvinyl butyral resin, the weight percentage of polyvinyl alcohol is 18% to 21%, and the weight percentage of polyvinyl acetate is 1% to 6%.

[0020] In an embodiment, the epoxy resin is at least one selected from glycidyl amine epoxy resin, multifunctional o-cresol novolac glycidyl ether type epoxy resin, phenol biphenyl epoxy resin, bisphenol F solid epoxy resin, isocyanate-modified epoxy resin, naphthol type epoxy resin, phenol novolac epoxy resin, semi-crystalline type epoxy resin, liquid bisphenol A type epoxy resin, liquid bisphenol F type epoxy resin, liquid bisphenol A-bisphenol F composite epoxy resin, liquid bisphenol S epoxy resin, liquid phenol novolac epoxy resin, and liquid phenol formaldehyde resin.

[0021] In an embodiment, the phenol resin is at least one selected from linear phenol formaldehyde resin and linear BPA formaldehyde resin.

[0022] In an embodiment, the content of the phenol resin and the content of the epoxy resin satisfy the following formula:

[0023] Phenolic resin content = (Hydroxyl equivalent weight of phenolic resin / Epoxy equivalent weight of epoxy resin) x Epoxy resin content.

[0024] In an embodiment, the inorganic filler is selected from at least one of graphite, carbon black, graphene, fullerene, silicon dioxide, aluminum trioxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium silicate, silicon carbide, titanium carbide, titanium oxide, magnesium oxide, calcium oxide, boron nitride, aluminum nitride.

[0025] In an embodiment, the composition comprises, by weight percentage:

[0026] 60% to 100% of the high molecular resin; and

[0027] 0% to 40% of the inorganic filler.

[0028] In an embodiment, in the high molecular resin, comprises, by weight percentage:

[0029] 30% to 80% of the structural resin;

[0030] 20% to 70% of the bonding resin; and

[0031] 0% to 20% of the cohesion enhancing resin.

[0032] In an embodiment, the hydrofluoric acid resistant composition further comprises a solvent selected from at least one of water, N-methyl pyrrolidone, ethanol, acetone, ethyl acetate, n-butyl ether, methyl tert-butyl ether, dimethyl phthalate, butanone, dimethyl sulfoxide, n-butanone, cyclohexanone, toluene, and xylene.

[0033] In an embodiment, the hydrofluoric acid resistant composition further comprises an aid comprising at least one of a leveling agent, a dispersant, and a defoaming agent.

[0034] In an embodiment, the content of the solvent is 0.5 times to 8 times of the total weight of the high molecular resin; and / or

[0035] The content of the aid is 0.5 weight percent to 5 weight percent of the total weight of the high molecular resin.

[0036] The present disclosure also proposes a preparation method of a hydrofluoric acid resistant composition for preparing the hydrofluoric acid resistant composition of any one of the preceding embodiments, the preparation method comprising the following steps:

[0037] Preparation of resin slurry: mixing the structural resin, the bonding resin, and the cohesion enhancing resin in a first solvent to obtain a resin slurry;

[0038] preparing a filler slurry: mixing the inorganic filler in a second solvent to obtain a filler slurry; and

[0039] mixing: mixing the filler slurry into the resin slurry under stirring to obtain a hydrofluoric acid resistant composition ink.

[0040] In an embodiment, at least one additive selected from a dispersant, a defoaming agent, and a leveling agent is pre-dissolved into the first solvent in the step of preparing the resin slurry; and / or

[0041] In an embodiment, at least one additive selected from a dispersant, a defoaming agent, and a leveling agent is pre-dissolved into the second solvent in the step of preparing the filler slurry.

[0042] In an embodiment, the mixing condition of the preparation method comprises at least one of the following:

[0043] the mixing speed is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 10 minutes and 50 minutes when preparing the resin slurry;

[0044] the mixing speed is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 10 minutes and 50 minutes when preparing the filler slurry; and

[0045] the mixing speed is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 60 minutes and 120 minutes when mixing the filler slurry with the resin slurry.

[0046] In an embodiment, after the mixing step, the preparation method further comprises:

[0047] preparing a dry film: applying the hydrofluoric acid resistant composition ink on a substrate film and performing a curing treatment to obtain a hydrofluoric acid resistant composition dry film.

[0048] In an embodiment, the curing treatment comprises:

[0049] baking the hydrofluoric acid resistant composition ink at a temperature range of 50°C to 120°C for 30 seconds to 30 minutes.

[0050] The present disclosure also provides a substrate processing method, comprising the following steps:

[0051] providing a substrate;

[0052] applying the composition: applying the hydrofluoric acid resistant composition of any one of the preceding embodiments on the surface of the substrate to form a protective layer on the surface of the substrate;

[0053] Etching process: etching the substrate on which the protective layer is formed using a hydrofluoric acid solution;

[0054] Removing the protective layer: removing the protective layer by placing the substrate after the etching process in a debinding solvent or by physical removal.

[0055] In one embodiment, when the hydrofluoric acid resistant composition is in the form of an ink, the step of applying the composition comprises:

[0056] Coating: coating the hydrofluoric acid resistant composition ink on the surface of the substrate by dip coating, screen printing, pad printing, steel screen printing, spraying or doctor blade printing; and

[0057] Curing: curing the hydrofluoric acid resistant composition ink coated on the surface of the substrate at a temperature of 50°C to 120°C for 3 minutes to 30 minutes to form the protective layer.

[0058] In one embodiment, when the hydrofluoric acid resistant composition is in the form of a dry film, the step of applying the composition comprises:

[0059] Hot pressing: hot pressing the hydrofluoric acid resistant composition dry film on the surface of the substrate at a temperature of 70°C to 150°C and a pressure of not less than 0.4 MPa for 30 seconds to 5 minutes to form the protective layer.

[0060] In one embodiment, the lamination is performed under a vacuum degree of less than 0.1 MPa.

[0061] In one embodiment, the step of etching process further comprises laser cutting the substrate before etching the substrate using the hydrofluoric acid solution.

[0062] In one embodiment, in the step of etching process, the concentration of the hydrofluoric acid solution is between 1% to 5% and the soaking time lasts for 30 seconds to 30 minutes.

[0063] In one embodiment, the debinding solvent is selected from at least one of N-methyl pyrrolidone, methanol, ethanol, n-butanol, acetone, ethyl acetate, n-butyl ether, methyl tert-butyl ether, dimethyl phthalate, butanone, dimethyl sulfoxide, n-butanone, cyclohexanone, toluene and xylene.

[0064] In one embodiment, the debinding solvent further contains 0.5% to 3% by weight of a surfactant.

[0065] In one embodiment, the step of removing the protective layer is performed at a temperature of 20°C to 60°C.

[0066] In an embodiment, the substrate is an ultra-thin glass having a thickness of no more than 70 microns.

[0067] The present application also provides a substrate prepared by the method of any one of the preceding methods.

[0068] The present application has the following advantages:

[0069] 1. Excellent hydrofluoric acid resistance and process compatibility: By non-polar synergistic compounding of structural resin and surface-modified inorganic filler, the hydrofluoric acid resistance of traditional protective materials (such as PO tape) can be greatly improved, achieving no peeling in 4% hydrofluoric acid solution for 5 minutes, thereby overcoming the existing material penetration defect and avoiding uneven etching. Moreover, the present application can directly improve the performance of ordinary coatings to be suitable for ultra-thin glass (≤70 μm) and other grades, having a significant process advantage.

[0070] 2. Excellent adhesion and interface compatibility: By cross-linking the network structure formed by the bonding resin and the strong bonding resin, the cured protective layer has excellent adhesion to the glass substrate, thereby solving the problem of poor adhesion and easy chipping of existing materials. The excellent adhesion ensures that the present application is very suitable for use as a temporary protective layer, ensuring the stability of the process and the integrity of the final substrate.

[0071] 3. High heat resistance, scratch resistance and removal optimization: The three-dimensional network formed by cross-linking the high molecular resin enables the cured protective layer to withstand high temperature conditions (resistant to 120°C) and withstand scratches during laser cutting without damage. At the same time, after etching, it can achieve very low residual risk, and can be quickly removed by alcohol (ethanol ultrasonic 3 min dissolution), which can greatly reduce the complexity of the process steps and improve the yield of ultra-thin glass. Moreover, it is precisely because the composition of the present application can still maintain excellent adhesion to the substrate under high hardness that it is very suitable for integrated processes of laser cutting + hydrofluoric acid etching, meeting the needs of high-speed processing of flexible displays and other applications. In addition, the present application also has the advantages of low water absorption (<1%) and high peelability, which can support gentle removal without coking problems.

[0072] 4. Flexible and diverse application forms: It can be made into ink or dry film form to achieve immersion coating / silk screen coating or vacuum lamination, and it is easy to remove the film with alcohol. At the same time, it can also be made into slurry form for overall protection of glass substrates. In addition, it can also be combined with a release film to be used as a temporary mask. BRIEF DESCRIPTION OF DRAWINGS

[0073] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments or prior art description. Obviously, the drawings in the following description only show some of the embodiments of the present application, and the ordinary skilled in the art can obtain other drawings from the drawings shown without any creative effort.

[0074] Figure 1 The flowchart of an embodiment of the method for preparing the hydrofluoric acid-resistant composition of the present application is shown.

[0075] Figure 2 The flowchart of an embodiment of the method for processing the substrate of the present application is shown.

[0076] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION

[0077] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the ordinary skilled in the art without any creative effort fall within the scope of protection of the present application.

[0078] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement condition, etc. between the components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications will also change accordingly.

[0079] In addition, if the embodiments of the present application involve descriptions of "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing throughout the text is that it includes three parallel solutions. Taking "A and / or B" as an example, it includes A solution, or B solution, or A and B solutions. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that the ordinary skilled in the art can realize it. When the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist, and is also not within the scope of protection claimed by the present application.

[0080] The present application provides a hydrofluoric acid resistant composition, which is aimed to form a protective layer that not only effectively resists etching by a hydrofluoric acid solution, but also can be dissolved and removed by soaking in a mild stripping solvent or removed by physical removal (such as tearing by hand, pasting with adhesive tape, etc.) after processing is completed, thereby fundamentally avoiding physical damage to the ultra-thin glass substrate.

[0081] In embodiments of the present application, the hydrofluoric acid resistant composition includes a high molecular resin and an inorganic filler, wherein the high molecular resin provides the composition with basic film-forming properties, adhesion to the substrate, core chemical resistance, and removability in a specific solvent, and the inorganic filler serves as a functional filler and can be used to improve the mechanical properties, scratch resistance, or assist processing of the composition.

[0082] Specifically, the high molecular resin includes a structural resin, a bonding resin, and a bonding strength enhancing resin.

[0083] The structural resin mainly plays a skeleton role in resisting chemical erosion in the composition, and its core function is to provide the protective layer formed by the final curing with excellent hydrofluoric acid resistance and acid and alkali corrosion resistance, thereby maintaining structural stability in a strong acid (such as hydrofluoric acid) environment and protecting the underlying substrate from etching. In a high filler system, the introduction of a large amount of inorganic fillers can improve hardness and scratch resistance, but can also easily cause the material to become brittle. The introduction of the structural resin can form a tough skeleton in the curing network, effectively absorbing and dispersing stress, thereby significantly improving the mechanical toughness and crack resistance of the entire hydrofluoric acid resistant composition. At the same time, its excellent chemical inertness is the key to ensuring that the material can resist the attack of strong acids (such as hydrofluoric acid, sulfuric acid, hydrochloric acid, etc.) in wet chemical processes such as etching by hydrofluoric acid. In addition, the structural resin can effectively reduce the overall permeability and improve the Tg point and thermal stability.

[0084] In some embodiments of the present application, the structural resin contains a fluorine-containing polymer. Such a polymer contains a highly stable carbon-fluorine bond in its molecular backbone. It is this non-reactive and hydrophobic chemical structure that gives it high chemical non-reactivity, enabling it to effectively resist the attack of strong acids and strong bases.

[0085] Specifically, the fluorine-containing polymer includes polyvinylidene fluoride (PVDF). Specifically, the structural formula of polyvinylidene fluoride is: The molecular weight of the composition is between 400,000 g / mol and 2,000,000 g / mol (i.e., 400,000 to 2,000,000). This range is set to balance the process flowability of the material and the corrosion resistance of the final cured material. If the molecular weight is below 400,000 g / mol, the composition can not form a film well, and the protective layer formed can not have sufficient mechanical strength and can swell or break easily in chemical immersion. If the molecular weight is above 2,000,000 g / mol, the composition can have too high a viscosity and can not dissolve uniformly in the solvent, which is not conducive to subsequent coating processing. By controlling the molecular weight in this range, the process adaptability of the composition in preparation and application is ensured, and at the same time, a dense skeleton is formed after curing, which resists the penetration of hydrofluoric acid solution.

[0086] The main function of the bonding resin, which is the core component of the system to form a three-dimensional crosslinked network and ensure strong adhesion to the substrate, is to form a dense and high-strength network structure through the curing reaction. This network not only tightly "glues" a large number of inorganic filler particles together to form a solid whole, but also enables the entire protective layer to form a firm chemical or physical bond with the surface of a glass substrate, a ceramic substrate, and other substrates with different properties. At the same time, the bonding resin can also form effective chemical or physical bonds with the structural resin and the surface of the inorganic filler to significantly improve the crosslinking density, hardness, heat resistance, and chemical resistance of the protective layer. Most importantly, the main chain structure retains the property of swelling or dissolving in a specific mild solvent (such as alcohol), which enables the protective layer formed by the hydrofluoric acid-resistant composition of the present application to be removed gently and non-destructively after use.

[0087] In some embodiments of the present application, the bonding resin comprises a polyvinyl acetal resin. Specifically, the polyvinyl acetal resin includes a polyvinyl butyral resin (PVB) having the following structural formula:

[0088] To ensure that the material has good film-forming properties and suitable solubility characteristics, the polyvinyl butyral resin used has a molecular weight of 5 g / mol to 10,000 g / mol. As specific, non-limiting examples, the polyvinyl butyral resin can have a molecular weight of 5 g / mol, 100 g / mol, 500 g / mol, 1,000 g / mol, 5,000 g / mol, or 10,000 g / mol.

[0089] PVB is chosen as the core adhesive resin because PVB resin itself contains a certain proportion of hydroxyl groups, which can form intermolecular and intramolecular hydrogen bonds in the polymer, increasing the intermolecular force. At the same time, due to the hydroxyl groups on the molecular chain, PVB can also cross-link with other thermosetting resins, such as phenolic, urea-formaldehyde, melamine, epoxy, etc. and diisocyanate, etc. By mixing in appropriate proportions, the brittleness and adhesion of the product can be improved, and the chemical resistance and coating hardness can be improved through bridging reactions.

[0090] Specifically, PVB also has excellent film-forming properties, transparency, and excellent mechanical toughness, which can provide a strong and flexible basic framework for the composite material. Moreover, the hydrophobic butyral groups and hydrophilic alcohol hydroxyl groups on the PVB molecular chain coexist, and this amphiphilic structure makes it have excellent adhesion to polar surfaces such as metals (such as copper) and inorganic materials (such as glass substrates), and also maintains good compatibility with other organic resins in the system.

[0091] More importantly, the alcohol hydroxyl groups on the PVB molecular chain not only provide adhesion, but also have chemical reactivity. These hydroxyl groups can cross-link with epoxy and phenolic resins in the adhesive resin during curing, so that the PVB as the matrix is no longer isolated, but is deeply integrated into the entire cross-linked network through chemical bonding. This co-reaction greatly enhances the cohesive strength, heat resistance, and overall structural density of the final protective film, enabling it to better resist high temperature and pressure and chemical erosion.

[0092] Finally, although PVB participates in the cross-linking reaction, its main chain structure and moderate cross-linking enable the entire system to remain strong while still retaining the property of swelling or dissolving in certain mild solvents such as alcohols. Moreover, by adjusting the proportion of alcohol hydroxyl, acetoxy, and butyral groups in the PVB raw material, the solubility, water resistance, and compatibility with other components can be precisely fine-tuned.

[0093] In some embodiments, in order to further precisely control the solubility, water resistance, and compatibility with other components of the material, the chemical composition of the PVB resin itself can be selected. Specifically, in polyvinyl butyral resin, the weight percentage of polyvinyl alcohol as the source of hydrophilicity can be between 11% and 27%, for example, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%; and the weight percentage of polyvinyl acetate can be between 0% and 8%, for example, 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%. By adjusting the proportion of these groups, the behavior of the final protective film in different solvents and the hydrolysis resistance can be finely tuned.

[0094] Preferably, the weight percentage of polyvinyl alcohol in the polyvinyl butyral resin is between 18% and 21%, and the weight percentage of polyvinyl acetate is between 1% and 6%.

[0095] Specifically, the preferred range of polyvinyl alcohol (alcohol hydroxyl) content is aimed at achieving the best balance between adhesion, reactivity and water resistance. Within the broader functional range of the present application (11% to 27%), when the polyvinyl alcohol content is in the lower range (e.g. 11% to 18%), the composite material has good peelability and sufficient adhesion, and exhibits stronger water resistance. When the content is in the higher range (e.g. 21% to 27%), the adhesion and reactivity of the material are further enhanced, and the stripping speed in alcohol solvents can be faster, but the sensitivity to moisture is correspondingly increased. In contrast, by controlling the polyvinyl alcohol content within the preferred optimal window of 18% to 21%, the material's hydrophilicity is maintained at an ideal level while providing excellent adhesion and cross-linking reactivity sufficient to meet various harsh processes, thereby maximizing its bonding and curing performance without sacrificing water resistance, and achieving the most balanced overall effect.

[0096] Similarly, the preferred range of polyvinyl acetate (acetoxy) content is aimed at fine-tuning the synergy between the hydrophobicity of the material and its core functionality. Within its broader functional range (0% to 8%), when the polyvinyl acetate content is in the higher range (e.g. 6% to 8%), the material's hydrolysis resistance is further improved, but the concentration of alcohol hydroxyl groups may be slightly diluted, which may have a subtle impact on adhesion or reactivity. By controlling the content within the preferred range of 1% to 6%, a sufficient amount of hydrophobic groups is introduced, which can significantly optimize and enhance the water resistance and environmental stability of the final protective film, but the content is not sufficient to have any substantial negative impact on the core functionality of alcohol hydroxyl groups (providing adhesion and reaction sites). Therefore, this range is the best choice for effectively enhancing the material's weather resistance without sacrificing core performance.

[0097] In summary, by limiting the content of polyvinyl alcohol and polyvinyl acetate to the preferred optimal window of 18%-21% and 1%-6% respectively, the PVB structural resin can achieve the best balance in adhesion, reactivity, water resistance and mild solvent solubility, thereby facilitating the removal of alcohol after hydrofluoric acid etching.

[0098] The bonding strength enhancing resin is used as an auxiliary component to increase the cross-linking density and pressure resistance. Its main function is to form a dense and high-strength network structure by bridging reaction with the hydroxyl groups in the bonding resin (PVB) through curing reaction. This network structure significantly improves the cross-linking density, hardness, heat resistance, chemical resistance, and bonding force with the adherend of the entire protective layer.

[0099] In some embodiments of the present application, the bonding strength enhancing resin comprises an epoxy resin and a phenolic resin as a cross-linking agent thereof.

[0100] To achieve fine adjustment of the final performance, the epoxy resin used in the present application can be one or a combination of various types of epoxy resins.

[0101] Specifically, the epoxy resin is selected from at least one of glycidyl amine epoxy resin, multifunctional o-cresol formaldehyde glycidyl ether type epoxy resin, phenol biphenyl epoxy resin, bisphenol F solid epoxy resin, isocyanate modified epoxy resin, naphthol type epoxy resin, phenol formaldehyde epoxy resin, semi-crystalline epoxy resin, liquid bisphenol A type epoxy resin, liquid bisphenol F type epoxy resin, liquid bisphenol A-bisphenol F composite epoxy resin, liquid bisphenol S epoxy resin, liquid phenol formaldehyde epoxy resin, and liquid phenol formaldehyde resin.

[0102] Specifically, the epoxy resin material used in the present application has an epoxy molecular weight of 2500 g / mol to 6000 g / mol:

[0103] The structural formula of the glycidyl amine epoxy resin is: Its epoxy equivalent weight is between 93-150 g / eq, the hydrolytic chlorine should be less than 200 ppm, and the viscosity at 25°C is between 0.5-5 Poise.

[0104] The structural formula of the functional o-cresol formaldehyde glycidyl ether type epoxy resin is: Its epoxy equivalent weight is between 195-230 g / eq, the hydrolytic chlorine at 120°C is between 470-1000 g / eq, the ICI viscosity at 150°C is between 0.9-60 Poise, and the softening point is 45-96°C.

[0105] The structural formula of the phenol biphenyl epoxy resin is: Its epoxy equivalent weight is between 261-280 g / eq, the hydrolytic chlorine should be less than 100 ppm, the viscosity at 25°C is between 0.1-4.5 Poise, and the softening point is 45-75°C. Adding to PVB and copolymerizing with its hydroxyl groups can effectively improve the glass strength with copper, Tg, and impact resistance.

[0106] The structural formula of the bisphenol F solid epoxy resin is: The epoxy equivalent weight is between 450-1000 g / eq, the hydrolytic chlorine should be less than 300 ppm, the viscosity at 25°C is <1000 Poise, and the softening point is 50-88°C. The solid bisphenol F type epoxy resin is characterized by low viscosity and flexibility, and the performance of its cured product is almost the same as that of bisphenol A type epoxy resin. When added to PVB and copolymerized with the hydroxyl group, the corrosion resistance can be effectively improved.

[0107] The structural formula of the isocyanate modified epoxy resin is:

[0108] The epoxy equivalent weight is between 280-380 g / eq, the hydrolytic chlorine should be less than 300 ppm, the viscosity at 25°C is between 0.5-3 Poise, and the softening point is 50-88°C. The solid isocyanate modified epoxy resin is characterized by low viscosity and flexibility, and the performance of its cured product is almost the same as that of bisphenol A type epoxy resin. When added to PVB and copolymerized with the hydroxyl group, the bonding strength and peel strength can be effectively improved.

[0109] The structural formula of the naphthol type epoxy resin is: The epoxy equivalent weight is between 280-380 g / eq, the hydrolytic chlorine should be less than 300 ppm, the viscosity at 25°C is between 0.5-3 Poise, and the softening point is 50-88°C. The naphthol type epoxy resin is superior to the traditional bisphenol A type in terms of curing property, heat resistance, and mechanical property. Due to its low internal stress, high Tg, and high bonding property, when added to the structural resin and copolymerized with the hydroxyl group, the Tg point, bonding strength, and peel strength can be effectively improved.

[0110] The structural formula of the phenol novolac epoxy resin is: The epoxy equivalent weight is between 165-200 g / eq, the hydrolytic chlorine should be less than 250 ppm, the viscosity at 25°C is between 1.1-12.5 Poise, and the softening point is 25-86°C. The phenol novolac epoxy resin has two or more epoxy groups in the molecular structure, so when added to the structural resin and copolymerized with the hydroxyl group, the product has a large crosslinking density, excellent bonding strength, heat resistance, and chemical resistance. Moreover, the phenol novolac epoxy resin has two or more epoxy groups in the molecular structure, so the cured product has a large crosslinking density, excellent bonding strength, heat resistance, and chemical resistance.

[0111] The structural formula of the semi-crystalline type epoxy resin is:

[0112] The structural formula of the liquid bisphenol A type epoxy resin and the liquid bisphenol F type epoxy resin is respectively:

[0113]

[0114] The structural formula of the liquid bisphenol A-bisphenol F composite epoxy resin is:

[0115] The structural formula of the liquid phenol-aldehyde epoxy resin is:

[0116] The structural formula of the liquid phenol-aldehyde resin is:

[0117] In the above-mentioned epoxy resins, the epoxy equivalent of the semi-crystalline epoxy resin, the liquid bisphenol A type epoxy resin, the liquid bisphenol F type epoxy resin, the liquid bisphenol A-bisphenol F composite epoxy resin, and the liquid bisphenol S epoxy resin is between 140 and 214 g / eq, the hydrolysis chlorine should be less than 250 ppm, and the viscosity at 25°C is between 1300 and 4500 mPa·s. The above-mentioned epoxy resins not only have low viscosity and large product cross-linking density, but also have excellent bonding strength, heat resistance, and chemical resistance. The main function is to control the resin flowability and the adhesion to the adherend, and it is particularly suitable for use on glass substrates.

[0118] In some embodiments of the present application, the phenol-aldehyde resin is selected from at least one of linear phenol formaldehyde resin and linear BPA formaldehyde resin.

[0119] Specifically, the structural formula of the linear phenol formaldehyde resin is: The free phenol content of which is less than 0.6%, the softening point is between 96 and 123°C, the hydroxyl equivalent is between 105 and 119 g / eq, and the conductivity is less than 8 us / cm.

[0120] The structural formula of the linear BPA formaldehyde resin is: The free phenol content of which is between 1 and 45%, the softening point is between 90 and 140°C, the hydroxyl equivalent is between 112 and 130 g / eq, and the conductivity is less than 20 us / cm.

[0121] The selection of these phenol-aldehyde resins, especially the low free phenol content and low conductivity category, is beneficial to ensure the stability of the curing reaction and the electrical insulation performance of the final protective layer.

[0122] In some embodiments, the content of the phenol-aldehyde resin and the content of the epoxy resin satisfy the following formula:

[0123] The content of the phenol-aldehyde resin = (the hydroxyl equivalent of the phenol-aldehyde resin / the epoxy equivalent of the epoxy resin) x the content of the epoxy resin.

[0124] Epoxy Equivalent Weight (EEW) refers to the grams of epoxy resin containing 1 mole of epoxy groups, and Hydroxyl Equivalent Weight (HEW) refers to the grams of phenolic resin containing 1 mole of phenolic hydroxyl groups. These two values are key parameters for measuring the reactivity of the resins. Therefore, the essence of the above formula is a mathematical conversion of the chemical equilibrium relationship that the number of moles of phenolic hydroxyl groups is approximately equal to the number of moles of epoxy groups. By using the formula, the amount of phenolic resin containing an equal number of moles of reactive sites that matches the amount of epoxy resin selected and its epoxy equivalent weight can be accurately calculated.

[0125] The fundamental reason for using the above formula to determine the amount of the two resins is to follow the stoichiometry principle in chemical reactions, aiming to achieve an ideal balance in the number of two core functional groups involved in the reaction, i.e., the phenolic hydroxyl groups (-OH) on the molecular chain of the phenolic resin and the epoxy groups on the molecular chain of the epoxy resin, so as to obtain a cured product with optimal performance.

[0126] Specifically, the curing process of the bonding strength enhancing resin is mainly through the ring-opening addition reaction of phenolic hydroxyl groups and epoxy groups to form a highly cross-linked three-dimensional network structure. In order to make this reaction proceed most completely and efficiently, theoretically, one phenolic hydroxyl functional group reacts with one epoxy functional group. Therefore, the ideal feed ratio should make the total number of moles of phenolic hydroxyl groups and the total number of moles of epoxy groups in the formulation as close to 1:1 as possible. Epoxy equivalent weight (EEW) refers to the grams of epoxy resin containing 1 mole of epoxy groups, and hydroxyl equivalent weight (HEW) refers to the grams of phenolic resin containing 1 mole of phenolic hydroxyl groups. By using the formula, the amount of phenolic resin that matches the amount of epoxy resin selected and its epoxy equivalent weight can be accurately calculated.

[0127] It can be understood that using this stoichiometry-based method to determine the ratio can ensure the full progress of the cross-linking reaction and avoid a large number of unreacted functional groups remaining in the cured network due to the excess of a certain component. This makes the final cured bonding strength enhancing resin have the highest cross-linking density, thereby obtaining more excellent heat resistance, chemical resistance, and the strongest mechanical strength and adhesion to the substrate.

[0128] The inorganic filler is mainly used as a mechanical property enhancer in the composition, which can significantly improve the mechanical properties (such as hardness, modulus), heat resistance, and dimensional stability of the protective layer formed by the composition. In this application, in order to improve the interfacial compatibility between the inorganic filler and the polymer resin matrix, prevent agglomeration at high content, and ensure that the two can effectively combine to transfer stress, the surface of the inorganic filler is modified with a specific functional group.

[0129] Specifically, the surface of the inorganic filler is modified with one or more functional groups selected from the group consisting of aniline groups, alkyl groups, nitrogen-containing functional groups in the main chain or side chain, double bond-containing functional groups, and epoxy groups. These functional groups can react with or form strong interactions with active groups in the high molecular resin, such as hydroxyl groups or epoxy groups, thereby tightly anchoring the inorganic filler in the resin matrix, so that the final protective layer has higher hardness, Young's modulus and bending modulus to effectively resist impact and thermal stress during etching processing.

[0130] In some embodiments, the inorganic filler is selected from at least one of graphite, carbon black, graphene, fullerene, silicon dioxide, aluminum trioxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium silicate, silicon carbide, titanium carbide, titanium oxide, magnesium oxide, calcium oxide, boron nitride, aluminum nitride. These inorganic fillers are filled into the high molecular resin matrix in appropriate proportions, and their core role is to serve as the reinforcing framework and functional body of the material, which can significantly improve the overall performance of the cured protective layer. On the one hand, these rigid inorganic filler particles can form a dense physical support network in the polymer matrix, thereby significantly improving the mechanical properties of the composite material, such as hardness, Young's modulus, tensile modulus and bending modulus, and enhancing its ability to maintain its shape during high temperature and high pressure processing. On the other hand, by introducing inorganic fillers, the thermal expansion coefficient (CTE) of the entire composition can be effectively reduced, and the thermal conductivity can be improved, thereby improving the heat dissipation efficiency and reliability of the protective layer, making it more suitable for ultra-thin glass processing applications.

[0131] The present application provides a variety of inorganic filler options, which can be optimized for specific performance of the hydrofluoric acid-resistant composition according to specific application requirements in actual operation. For example, selecting black fillers such as graphite or carbon black can help absorb infrared laser energy, which is helpful for laser cutting processing; selecting high-hardness fillers such as silicon dioxide can effectively improve the scratch resistance and mechanical strength of the material. It can be understood that by selectively combining and compounding the above-mentioned inorganic fillers, the present application can flexibly adjust the performance indicators of the hydrofluoric acid-resistant composition to meet the diversified needs of different specifications of glass substrates under specific processing techniques.

[0132] In some embodiments, the relative content of each main component in the composition is limited to achieve the best balance of performance indicators. Specifically, the hydrofluoric acid-resistant composition can contain 60% to 100% (e.g., 60%, 70%, 80%, 90%, 100%, etc.) of high molecular resin, and 0% to 40% (e.g., 0%, 10%, 20%, 30%, 40%, etc.) of inorganic filler by weight percentage.

[0133] Specifically, the inorganic filler is the core component that imparts high mechanical strength, low coefficient of thermal expansion (CTE), and high scratch resistance to the final protective layer. By controlling its content within the range of 0% to 40%, it is possible to ensure that the protective layer formed after curing has sufficient rigidity and dimensional stability to effectively cope with the thermal-mechanical stress brought about by processes such as laser cutting and hydrofluoric acid etching. If the content of the inorganic filler is higher than 40%, although its contribution to reducing the coefficient of thermal expansion and improving mechanical properties is significant, it can lead to excessively high viscosity of the composition, affecting the uniformity of coating.

[0134] The high molecular resin, on the other hand, serves as the continuous phase matrix, playing the role of tightly binding the inorganic filler particles together and enabling the entire protective layer to firmly adhere to the glass substrate. If the content of the high molecular resin is lower than 60%, it is insufficient to form a continuous and complete resin network to encapsulate and bind the inorganic filler, which can lead to problems such as poor film-forming properties, brittle material, and insufficient adhesion.

[0135] Therefore, by controlling the weight percentages of the high molecular resin and the inorganic filler within the ranges of 60% to 100% and 0% to 40% respectively, the present application achieves the optimal balance between excellent mechanical corrosion resistance and good film-forming properties and adhesion, ensuring that the composition can form a uniform, high-adhesion protective layer and also provide sufficient rigidity and dimensional stability after curing to cope with subsequent complex processes.

[0136] In some embodiments of the present application, in the high molecular resin, there are 30% to 80% (e.g. 30%, 40%, 50%, 60%, 70%, 80%, etc.) of structural resin, 20% to 70% (e.g. 20%, 30%, 40%, 50%, 60%, 70%, etc.) of bonding resin, and 0% to 20% (e.g. 0%, 5%, 10%, 15%, 20%, etc.) of adhesion-enhancing resin, by weight percentage.

[0137] The proportioning of the various components within the high molecular resin is designed to precisely balance the multiple core properties that the present application's hydrofluoric acid-resistant composition seeks to achieve: namely, outstanding corrosion and chemical resistance, strong adhesion to the substrate, and excellent mechanical toughness.

[0138] As previously mentioned, the structural resin is the main backbone of the polymer system, and is the functional mainstay that provides the final protective layer with excellent acid and heat resistance. In order to ensure that the protective layer remains structurally intact and does not penetrate or erode during hydrofluoric acid etching and subsequent wet chemical processing, the structural resin must dominate the entire polymer system. By controlling its content within the higher range of 30% to 80%, a strong, stable, high-performance polymer network can be formed after curing. If the content of the structural resin is less than 30%, the corrosion resistance and chemical resistance provided by it will be insufficient, which can cause the material to become brittle under high filler or be unable to withstand strong acid attacks. If the content of the structural resin is higher than 80%, the content of the bonding resin will be correspondingly squeezed (to less than 20%), which can cause the failure of two key performances: first, the bonding resin is the main source of adhesion to the glass substrate, and a low content can cause insufficient adhesion between the protective layer and the substrate, which can easily fall off during etching; second, the bonding resin is the core component that gives the protective layer the solubility in alcohol, and a low content can destroy this property, making the protective layer unable to be removed gently after processing.

[0139] The bonding resin (polyvinyl acetal) is the key to providing strong adhesion to glass substrates and forming a dense cross-linked network to bond inorganic fillers. If the content of the bonding resin is less than 20%, its cross-linking and bonding effect will not be obvious, and the protective layer formed will have poor adhesion and a loose internal structure. Conversely, if its content is higher than 70%, it will result in a high cross-linking density, increasing the brittleness of the entire polymer system, and its relatively high hydrophilicity can also have a negative impact on the final water resistance.

[0140] The adhesion-enhancing resin (epoxy and phenolic system) is the core functional component that achieves high cross-linking density. If its content is less than 0%, the strengthening effect will be insufficient; if it is higher than 20%, it can affect the compatibility of the system and weaken the adhesion of the protective layer to the substrate. Therefore, by precisely controlling the content of the structural resin, the bonding resin, and the adhesion-enhancing resin within the above-mentioned optimal ranges, the mechanical toughness, chemical resistance, and strong adhesion to the substrate of the material are perfectly balanced on the premise of ensuring super-strong corrosion resistance, achieving the best balance of comprehensive performance.

[0141] In some embodiments, in order to further improve the process performance of the hydrofluoric acid-resistant composition during preparation, storage, and coating, and the final film formation quality, the composition also contains a solvent selected from at least one of water, N-methyl pyrrolidone, ethanol, acetone, ethyl acetate, n-butyl ether, methyl tert-butyl ether, dimethyl phthalate, butanone, dimethyl sulfoxide, n-butanone, cyclohexanone, toluene, and xylene.

[0142] Specifically, the solvent in the composition mainly acts as a carrier medium, the core function of which is to dissolve the high molecular resin (including structural resin, bonding resin and bonding strength resin), and uniformly disperse the inorganic filler and other additives, forming a uniform, stable and suitable viscosity liquid or paste system. The present application provides diversified solvent selection, in order to be able to flexibly construct the best solvent system according to the solubility parameter of the specific high molecular resin selected. For example, high boiling point strong polar solvents such as N-methyl pyrrolidone have excellent effect on dissolving high performance polymers such as polyvinylidene fluoride; and low boiling point solvents such as butanone and toluene can help to volatilize quickly during the baking process, improving production efficiency. By using these solvents alone or in combination, the viscosity, surface tension, drying rate and storage stability of the final composition can be accurately controlled, so as to ensure that it can perfectly adapt to different industrial production processes.

[0143] In some embodiments, the content of the solvent is 0.5 to 8 times the total weight of the high molecular resin. Specifically, if the content of the solvent is less than 0.5 times, the viscosity of the composition may be too high to dissolve or disperse each component; if it is higher than 8 times, the solid content is too low to form a film layer with effective thickness, and the drying time is too long. Therefore, by this content range, it is ensured that the composition has sufficient flowability for coating, while avoiding film shrinkage caused by excessive solvent.

[0144] In some embodiments, the hydrogen fluoride resistant composition of the present application further comprises an additive, which comprises at least one of a leveling agent, a dispersant and a defoaming agent. The addition of these additives aims to optimize the physical and chemical behavior of the composition during preparation, storage and coating, etc.

[0145] Specifically, the main role of the dispersant is to improve and stabilize the dispersion state of the inorganic filler in the resin matrix, effectively preventing the aggregation and sedimentation between particles through electrostatic repulsion or steric hindrance effect, so as to ensure the uniformity and storage stability of the slurry.

[0146] The main role of the leveling agent is to improve the surface appearance of the composition during the process of coating and film forming, reduce the surface tension of the slurry, promote its flow and spreading on the substrate, eliminate defects such as orange peel and shrinkage, so that the surface of the protective layer formed finally is more smooth and flat.

[0147] The main role of the defoaming agent is to eliminate the bubbles brought in by high-speed stirring or shearing, avoid the formation of pinholes or voids by residual bubbles, and weaken the density and mechanical strength of the protective layer.

[0148] In a specific embodiment, examples of additives that can be used include leveling agent BYK530, dispersant BYK 2152 and defoaming agent BYK333.

[0149] It can be understood that by introducing these specific functional additives, the present application can ensure the stability and reliability of its resin composition during preparation and application, thereby providing a strong guarantee for the final formation of high-quality and high-performance hydrofluoric acid-resistant protective layers.

[0150] In some embodiments, the content of the additive is 0.5 to 5 percent by weight of the total weight of the high molecular resin. Specifically, if the content of the additive is less than 0.5%, its effect on improving processability is not obvious; if it is higher than 5%, it may have an adverse effect on the core performance of the final protective layer, such as acid resistance or adhesion. Therefore, by this content range, the additive can play a role without affecting the overall performance of the composition.

[0151] In summary of the above embodiments, the hydrofluoric acid-resistant composition proposed in the present application has the following beneficial effects:

[0152] 1. Excellent hydrofluoric acid resistance and processing compatibility: through the non-polar synergistic compounding of structural resin and surface-modified inorganic filler, the acid resistance of traditional protective materials (such as PO tape) can be greatly improved, achieving no shedding in 4% hydrofluoric acid solution for 5 minutes, thereby overcoming the penetration defect of existing materials and avoiding uneven etching. Moreover, the present application can directly improve the performance of ordinary coatings to a level suitable for ultra-thin glass (≤70 μm) and other grades, having a significant process advantage.

[0153] 2. Excellent adhesion and interface compatibility: through the cross-linking of bonding resin and binding force-enhancing resin to form a network structure, the cured protective layer has excellent adhesion to the glass substrate, thereby solving the problem of poor adhesion and easy chipping of existing materials. The excellent adhesion ensures that the present application is very suitable for use as a temporary protective layer, ensuring the stability of the process and the integrity of the final substrate.

[0154] 3. High heat and scratch resistance and removal optimization: through the three-dimensional network formed by the cross-linking of high molecular resin, the cured protective layer can withstand high temperature conditions (resistant to 120°C) and scratches during laser cutting without damage. At the same time, after etching, it can achieve extremely low residual risk and be quickly removed by alcohol (ethanol ultrasonic 3 min dissolution), which can greatly reduce the complexity of the processing steps and improve the yield of ultra-thin glass. Moreover, it is precisely because the composition of the present application can still maintain excellent adhesion to the substrate at high hardness that it is very suitable for integrated processes of laser cutting + hydrofluoric acid etching, meeting the needs of high-speed processing such as flexible display. In addition, the present application also has the advantages of low water absorption (<1%) and high peelability, which can support removal under mild conditions without causing scorching problems.

[0155] 4. Application form flexible: can be made into ink or dry film form, realize dip coating / screen printing coating or vacuum lamination, and be convenient for alcohol liquid film stripping. At the same time, can also be made into slurry form, used for overall protection of glass substrate. In addition, can also be combined with a release film, used as a temporary mask.

[0156] The present application also provides a preparation method of the hydrofluoric acid resistant composition, for preparing the hydrofluoric acid resistant composition of any one of the preceding.

[0157] As shown in Figure 1 In some embodiments, the preparation method comprises the following steps:

[0158] S1, preparing resin slurry: mixing structural resin, bonding resin and bonding force strengthening resin in a first solvent to obtain resin slurry.

[0159] This step aims to obtain uniform and gel-free resin slurry as the basis for subsequent filler dispersion. Specifically, the structural resin (providing corrosion-resistant skeleton), the bonding resin (ensuring cross-linking adhesion and alcohol solubility) and the bonding force strengthening resin (improving cross-linking density) are mixed together in the first solvent. Among them, the structural resin is polyvinylidene fluoride (molecular weight 400000g / mol to 2000000g / mol), the bonding resin is polyvinyl butyral resin (polyvinyl alcohol content 18% to 21%, polyvinyl acetate content 1% to 6%), and the bonding force strengthening resin is formula phenolic resin content=(hydroxyl equivalent weight of phenolic resin / epoxy equivalent weight of epoxy resin) x epoxy resin content.

[0160] In a preferred embodiment, in order to improve the mixing effect of the subsequent step, at least one auxiliary selected from dispersant, defoamer and leveling agent can be pre-added to the first solvent before adding the high molecular resin component. Examples of auxiliary that can be used include but are not limited to products such as BYK2152, BYK530 and BYK333. The pre-addition of these auxiliaries can wet the surface of the resin particles, effectively prevent the agglomeration and sedimentation of the resin components in the solvent through electrostatic repulsion or steric hindrance effect, so as to ensure the uniformity and storage stability of the slurry.

[0161] Specifically, the mixing process for preparing the resin slurry can be realized by high-speed stirring equipment such as homogenizer. Of course, the homogenizer can be replaced by emulsifier, high-speed stirrer or impactor.

[0162] In some embodiments, the mixing speed for preparing the resin slurry is 3600-7200 rpm. In order to prevent the resin stability from being affected by the heat generated by high-speed shearing, the whole process can be carried out in a reaction kettle with a cooling water jacket to ensure that the slurry temperature is not higher than 45°C. The mixing duration is 10-50 minutes, for example, 30 minutes, to ensure the formation of a uniform and stable resin slurry (also referred to as slurry A).

[0163] The reasons for setting the speed, temperature and time are as follows:

[0164] The speed of 3600-7200 rpm provides sufficient shearing force to disperse the resin particles. If the speed is too low (e.g. lower than 3600 rpm), the mixing may not be sufficient, leading to phase separation.

[0165] The temperature is not higher than 45°C to avoid pre-crosslinking of the resin. If the temperature is higher than 45°C, the combined strength resin (e.g. epoxy / phenolic system) is prone to premature reaction, shortening the storage period.

[0166] The duration is limited to 10-50 minutes to balance efficiency and thoroughness. If the duration is shorter than 10 minutes, the slurry may not be uniformly dispersed, and if it is longer than 50 minutes, it will increase energy consumption without additional benefits.

[0167] Through the control of the above parameters, the viscosity of the resin slurry is moderate (1000-5000 mPa·s), laying a foundation for subsequent filler integration.

[0168] S2, preparing a filler slurry: mixing inorganic fillers in a second solvent to obtain a filler slurry.

[0169] This step aims to obtain a non-agglomerated filler slurry, ensuring uniform dispersion of inorganic fillers and avoiding subsequent uneven compounding. Specifically, surface-modified inorganic fillers (e.g. silica modified with aniline groups) are mixed in a second solvent. The inorganic fillers provide mechanical reinforcement, and the surface-modified functional groups improve interfacial compatibility.

[0170] In a preferred embodiment, at least one auxiliary agent selected from a dispersing agent, a defoaming agent and a leveling agent can be pre-added to the second solvent before the inorganic fillers are added, to improve the dispersion efficiency of the fillers. This process can use similar equipment and process parameters as step S1, for example, using a homogenizer at a speed of 3600-7200 rpm and a temperature not higher than 45°C, and the duration is 10-50 minutes, for example, 30 minutes, to ensure that the inorganic filler particles are fully wetted and uniformly dispersed, forming a non-agglomerated filler slurry (also referred to as slurry B).

[0171] It is worth mentioning that the first solvent and the second solvent can be the same or different. Specifically, the first solvent and the second solvent are selected from at least one of water, N-methyl pyrrolidone, ethanol, acetone, ethyl acetate, n-butyl ether, methyl tert-butyl ether, dimethyl phthalate, butanone, dimethyl sulfoxide, n-butanone, cyclohexanone, toluene, and xylene.

[0172] S3, mixing: the filler slurry is poured into the resin slurry in agitation for mixing to obtain the hydrofluoric acid resistant composition ink in the form of slurry.

[0173] This step aims to achieve organic-inorganic uniform compounding to form the final slurry. Specifically, the prepared filler slurry (slurry B) is slowly added to the resin slurry (slurry A) in agitation to prevent filler agglomeration due to excessive local concentration. After the addition is completed, the homogenizer or other equipment is continued to be used for sufficient mixing to ensure that the filler particles achieve the best dispersion state in the final resin composition.

[0174] The process parameters of this final mixing step are rotation speed of 3600-7200 rpm, temperature not higher than 45°C, and duration of 60-120 minutes, for example 90 minutes, to obtain the final hydrofluoric acid resistant composition in the form of slurry. The rotation speed and temperature setting are the same as S1 / S2 to ensure shear force and heat control; the time is extended to 60-120 minutes to ensure that the filler particles achieve the best dispersion state in the final resin composition.

[0175] After the mixing step, the preparation method of the present application can further include a post-processing step:

[0176] S4, preparation of dry film: the hydrofluoric acid resistant composition ink is coated on a substrate film and subjected to a curing treatment to obtain the hydrofluoric acid resistant composition dry film.

[0177] This step aims to convert the hydrofluoric acid resistant composition prepared in the previous steps in the form of ink into a solid dry film with a specific thickness, uniformity, and ease of subsequent application by hot pressing.

[0178] Specifically, the hydrofluoric acid resistant composition ink is uniformly coated on a substrate film by means of doctor blade printing, dip coating, or screen printing, etc. The substrate film is usually a release film, such as a PET (polyethylene terephthalate) film. After coating, the substrate film coated with the composition ink is subjected to a curing treatment to remove the solvent and form a solid thin film with certain mechanical strength, thereby obtaining the hydrofluoric acid resistant composition dry film.

[0179] In some embodiments, the curing treatment is preferably a drying procedure performed in a hot air oven. The procedure includes drying the hydrofluoric acid resistant composition ink at a temperature range of 50-120°C for 30 seconds to 30 minutes.

[0180] The above process conditions are limited for the following reasons:

[0181] Temperature (50°C to 120°C): The lower limit of temperature is set to 50°C to ensure that sufficient energy is provided to the solvent molecules to efficiently escape from the coating. If the temperature is lower than 50°C, the evaporation rate of the solvent will be too slow, which can result in residual solvent inside the film, making the final dry film soft, sticky or insufficient in mechanical strength. The upper limit of temperature is controlled at 120°C to ensure efficient evaporation of the solvent while avoiding significant premature crosslinking of the strong bonding resin (epoxy / phenolic system). If the temperature is too high, it can result in over-curing of the dry film (i.e. "dead"), thus losing the necessary flowability when subsequently thermo-compressed to a substrate, affecting the lamination effect.

[0182] Time (30 seconds to 30 minutes): The lower limit of time is set to 30 seconds to ensure that there is sufficient time for the solvent inside the film to be sufficiently evaporated to form a stable solid film. If the baking time is too short, it can result in incomplete curing, affecting the handling of the dry film. The upper limit of time is controlled at 30 minutes to ensure complete removal of the solvent while taking into account the efficiency of industrial production. Beyond this time, the performance of the dry film is not significantly improved, but the output efficiency of the production line is reduced.

[0183] In summary, the preparation method of the hydrofluoric acid-resistant composition according to the present application has the following beneficial effects:

[0184] 1. Efficient dispersion and stability: By step-by-step slurry preparation and additive pre- addition, uniform resin / filler compounding is achieved, agglomeration is avoided, and slurry storage period is improved.

[0185] 2. Process flexibility: Parameter range (rotation speed / temperature / time) is suitable for industrial scale, and the choice of solvent / additive can optimize coating precision.

[0186] 3. Performance synergy: The obtained slurry does not fall off after being immersed in 4% hydrofluoric acid for 5 minutes after curing, and the alcohol is easy to remove, which helps to improve the processing yield of ultra-thin glass.

[0187] The present application also proposes a processing method for a substrate, which applies the aforementioned hydrofluoric acid-resistant composition as a high-performance temporary protective material to construct a protective structure with excellent corrosion resistance and processing compatibility in the manufacturing process of a glass substrate, especially ultra-thin glass.

[0188] Referring to Figure 2 in one embodiment, the processing method comprises the following steps:

[0189] S10, providing a substrate: first, a substrate to be processed is provided.

[0190] This step aims to prepare the substrate to be processed as the basis for subsequent protection and etching. Specifically, an ultra-thin glass substrate (e.g., ultra thin glass, UTG) with a thickness of no more than 70 microns can be provided, and the surface thereof needs to be clean and free of oil stains to ensure uniform adhesion of the protective layer. The substrate is widely used in flexible display, folding screen and other fields, and the thickness is controlled below 70 microns to meet the demand of high-precision laser cutting, and at the same time, the protection applicability of the method to fragile substrates is highlighted.

[0191] In a preferred embodiment, the substrate can be cleaned by ultrasonic cleaning (e.g., using deionized water, frequency 40 kHz, for 5 minutes) to remove surface contaminants and avoid subsequent coating defects.

[0192] S20, applying a composition: applying the hydrofluoric acid-resistant composition of any one of the preceding embodiments to the surface of the substrate to form a protective layer on the surface of the substrate.

[0193] This step aims to uniformly apply the hydrofluoric acid-resistant composition to the substrate to form an initial protective layer. The function of this step is to isolate the substrate surface from the subsequent hydrofluoric acid solution to ensure etching selectivity; its position in the entire method is the starting link of the processing chain, providing a mechanical barrier and a chemically inert basis. The application of the composition is not limited to a specific form, for example, the composition in the form of ink can be achieved by coating or dry film lamination.

[0194] In some embodiments, when the composition in the form of ink is used, step S20 is implemented by steps S21-S22:

[0195] S21, coating: coating the hydrofluoric acid-resistant composition in the form of slurry on the surface of the substrate by dip coating, screen printing, pad printing, steel screen printing, spraying or doctor blade printing.

[0196] S22, curing: drying the hydrofluoric acid-resistant composition coated on the surface of the substrate at a temperature of 50°C to 120°C for 3 minutes to 30 minutes to form the protective layer.

[0197] Specifically, the coated substrate can be placed in a hot air furnace at a temperature of 80°C for 10 minutes to remove the solvent and form a dense protective layer. In this process, the temperature is set to 50°C to 120°C because below 50°C, the solvent volatilizes slowly and the film layer is loose; above 120°C, the resin is pre-crosslinked, which affects removal. The time is set to 3 to 30 minutes to balance the efficiency: if less than 3 minutes, there is more residual solvent, and if more than 30 minutes, the energy consumption increases but there is no obvious benefit.

[0198] In other embodiments, when the composition is in the dry film form, step S20 is achieved by step S23.

[0199] First, in step S23, the hydrogen fluoride resistant composition in the paste form is coated on the release film, and then heated at a temperature ranging from 70°C to 150°C for 30 seconds to 5 minutes to form the dry film.

[0200] Step S23, hot pressing: the hydrogen fluoride resistant composition in the dry film form is hot pressed on the surface of the substrate at a temperature ranging from 70°C to 150°C and a pressure not less than 0.4 MPa for 30 seconds to 5 minutes to form the protective layer. When the vacuum laminator is used for lamination, the lamination is preferably performed under a vacuum degree less than 0.1 MPa to ensure that the air between the substrate and the dry film is completely removed during the lamination process to prevent the generation of air bubbles.

[0201] S30, etching processing: the substrate with the protective layer is etched using a hydrofluoric acid solution. Since the protective layer has excellent acid resistance, it can protect the substrate area covered thereby from being eroded.

[0202] In a preferred embodiment, the step of etching processing further comprises: before etching the substrate using the hydrofluoric acid solution, the substrate is first subjected to laser cutting. The laser cutting is used to define the shape of the substrate, and the subsequent hydrofluoric acid etching is used to remove the edge burrs and micro-cracks caused by the laser cutting.

[0203] Specifically, the substrate is first subjected to laser cutting to form cracks in the edge area; then, the cut substrate is soaked in a hydrofluoric acid solution with a concentration of 1% to 5% (for example, 3%) for 30 seconds to 30 minutes (for example, 2 minutes) to accurately etch the burrs. After soaking, the substrate can be rinsed with pure water and dried.

[0204] The concentration of the hydrofluoric acid is set to 1% to 5% because, below 1%, the etching rate is slow and the efficiency is low; above 5%, the risk of penetration of the protective layer increases, although the present composition does not fall off in 4% hydrofluoric acid for 5 minutes, safety needs to be balanced.

[0205] The time of 30 seconds to 30 minutes is to adapt to different burr depths: shorter than 30 seconds is not completely removed, and longer than 30 minutes is easy to over-etch.

[0206] S40, removing the protective layer: the substrate after etching processing is placed in a film-removing solvent or removed by physical means to remove the protective layer.

[0207] This step aims to gently peel off the protective layer and restore the surface of the substrate.

[0208] Specifically, the processed substrate is placed in a stripping solvent selected from at least one of N-methyl pyrrolidone, methanol, ethanol, n-butanol, acetone, ethyl acetate, n-butyl ether, methyl tert-butyl ether, dimethyl phthalate, butanone, dimethyl sulfoxide, n-butanone, cyclohexanone, toluene and xylene (e.g. ethanol), and is carried out at a temperature environment of 20-60°C (e.g. 40°C). With this mild temperature condition, the protective layer can be effectively dissolved, and additional thermal stress on the ultra-thin substrate caused by high temperature can be avoided.

[0209] The removal can be carried out by spraying or soaking, and in order to further accelerate the removal rate, the removal step can be combined with ultrasonic oscillation treatment. After the protective layer is completely removed, the processed substrate is then rinsed with deionized water to completely remove the residual stripping solvent and dissolved composition, and a clean substrate product is obtained.

[0210] In some embodiments, the stripping solvent contains 0.5-3 wt% of an interfacial active agent (such as a fatty alcohol polyoxyethylene ether) to enhance wetting and penetration.

[0211] It is worth noting that in some embodiments, as an alternative implementation, step S40 can also be removed by physical removal when removing the protective layer, such as hand tearing, tape tearing, etc. In this way, the protective layer can also be removed gently without causing damage to the substrate.

[0212] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made under the inventive concept of the present application, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present application.

Claims

1. A hydrofluoric acid resistant composition, characterized in that, Including polymer resins and inorganic fillers, among which, The polymer resin includes: Structural resin, wherein the structural resin comprises a fluoropolymer; The adhesive resin comprises a polyvinyl acetal resin; and A bonding-strengthening resin, wherein the bonding-strengthening resin comprises epoxy resin and phenolic resin; The surface of the inorganic filler is modified with one or more functional groups selected from the group consisting of aniline, alkyl, nitrogen-containing functional groups on the main chain or branches, double-bonded functional groups, and epoxy groups.

2. The hydrofluoric acid resistant composition according to claim 1, characterized in that, The fluoropolymer includes polyvinylidene fluoride.

3. The hydrofluoric acid resistant composition according to claim 2, characterized in that, The molecular weight of the polyvinylidene fluoride is between 400,000 g / mol and 2,000,000 g / mol.

4. The hydrofluoric acid resistant composition according to claim 1, characterized in that, The polyvinyl acetal resins include polyvinyl butyral resins.

5. The hydrofluoric acid resistant composition according to claim 4, characterized in that, The molecular weight of the polyvinyl butyral resin is between 5 g / mol and 10,000 g / mol.

6. The hydrofluoric acid resistant composition according to claim 4, characterized in that, In the polyvinyl butyral resin, the weight percentage of polyvinyl alcohol is between 11% and 27%, and the weight percentage of polyvinyl acetate is between 0% and 8%.

7. The hydrofluoric acid resistant composition according to claim 6, characterized in that, In the polyvinyl butyral resin, the weight percentage of polyvinyl alcohol is between 18% and 21%, and the weight percentage of polyvinyl acetate is between 1% and 6%.

8. The hydrofluoric acid resistant composition according to claim 1, characterized in that, The epoxy resin is selected from at least one of the following: glycidylamine epoxy resin, polyfunctional o-cresol glycidyl ether epoxy resin, phenol-biphenyl epoxy resin, bisphenol F solid epoxy resin, isocyanate modified epoxy resin, naphthol epoxy resin, phenol-formaldehyde epoxy resin, semi-crystalline epoxy resin, liquid bisphenol A epoxy resin, liquid bisphenol F epoxy resin, liquid bisphenol A-bisphenol F composite epoxy resin, liquid bisphenol S epoxy resin, liquid phenolic epoxy resin, and liquid phenolic resin.

9. The hydrofluoric acid resistant composition according to claim 1, characterized in that, The phenolic resin is selected from at least one of linear phenol-formaldehyde resin and linear BPA-formaldehyde resin.

10. The hydrofluoric acid resistant composition according to claim 1, characterized in that, The content of the phenolic resin and the content of the epoxy resin satisfy the following formula: Phenolic resin content = (hydroxyl equivalent of phenolic resin / epoxy equivalent of epoxy resin) × epoxy resin content.

11. The hydrofluoric acid resistant composition according to claim 1, characterized in that, The inorganic filler is selected from at least one of graphite, carbon black, graphene, fullerene, silicon dioxide, aluminum oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium silicate, silicon carbide, titanium carbide, titanium oxide, magnesium oxide, calcium oxide, boron nitride, and aluminum nitride.

12. The hydrofluoric acid-resistant composition according to any one of claims 1 to 11, characterized in that, The composition comprises, by weight percentage: 60% to 100% of the aforementioned polymeric resin; and The inorganic filler content is 0% to 40%.

13. The hydrofluoric acid resistant composition according to claim 12, characterized in that, The polymer resin contains, by weight percentage: 30% to 80% of the structural resin; 20% to 70% of the adhesive resin; and 0% to 20% of the bonding strength strengthening resin.

14. The hydrofluoric acid resistant composition according to claim 1, characterized in that, The hydrofluoric acid resistant composition further comprises a solvent selected from at least one of water, N-methylpyrrolidone, ethanol, acetone, ethyl acetate, n-butyl ether, methyl tert-butyl ether, dimethyl phthalate, butanone, dimethyl sulfoxide, n-butyl ketone, cyclohexanone, toluene, and xylene.

15. The hydrofluoric acid resistant composition according to claim 13, characterized in that, The hydrofluoric acid resistant composition further comprises an additive, which includes at least one of a leveling agent, a dispersant, and a defoamer.

16. The hydrofluoric acid resistant composition according to claim 15, characterized in that, The solvent content is 0.5 to 8 times the total weight of the polymer resin; and / or The content of the additive is 0.5% to 5% by weight of the total weight of the polymer resin.

17. A method for preparing a hydrofluoric acid-resistant composition, used to prepare the hydrofluoric acid-resistant composition according to any one of claims 1 to 16, characterized in that, The preparation method includes the following steps: Preparation of resin slurry: The structural resin, the bonding resin and the binding strength reinforcing resin are mixed in a first solvent to obtain a resin slurry; Preparation of filler slurry: The inorganic filler is mixed in a second solvent to obtain a filler slurry; and Mixing: The filler slurry is added to the resin slurry being stirred and mixed to obtain a hydrofluoric acid resistant composition ink.

18. The method for preparing the hydrofluoric acid resistant composition according to claim 17, characterized in that, In the step of preparing the resin slurry, at least one additive selected from dispersants, defoamers, and leveling agents is pre-dissolved in the first solvent; and / or In the step of preparing the filler slurry, at least one additive selected from dispersants, defoamers and leveling agents is pre-dissolved in the second solvent.

19. The method for preparing the hydrofluoric acid resistant composition according to claim 17, characterized in that, The mixing conditions of the preparation method include at least one of the following: The mixing speed during the preparation of the resin slurry is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 10 minutes and 50 minutes. The mixing speed during the preparation of the filler slurry is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 10 minutes and 50 minutes; and The mixing speed of the filler slurry and the resin slurry is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 60 minutes and 120 minutes.

20. The method for preparing the hydrofluoric acid resistant composition according to any one of claims 17 to 19, characterized in that, Following the mixing step, the preparation method further includes: Preparation of dry film: The hydrofluoric acid resistant composition ink is coated onto the substrate film and cured to obtain the hydrofluoric acid resistant composition dry film.

21. The method for preparing the composite dielectric sheet fabric as described in claim 20, characterized in that, The curing process includes: The hydrofluoric acid resistant composition ink is dried in a temperature range of 50°C to 120°C for 30 seconds to 30 minutes.

22. A method for processing a substrate, characterized in that, Includes the following steps: Provide substrate; Application of composition: The hydrofluoric acid resistant composition according to any one of claims 1 to 16 is applied to the surface of the substrate to form a protective layer on the surface of the substrate; Etching process: The substrate on which the protective layer is formed is etched using a hydrofluoric acid solution; Remove the protective layer: The substrate after etching is placed in a stripping solvent or removed by physical means to remove the protective layer.

23. The substrate processing method as described in claim 22, characterized in that, When using an ink-form hydrofluoric acid-resistant composition, the step of applying the composition includes: Coating: Applying a hydrofluoric acid resistant composition ink to the surface of the substrate by means of dip coating, screen printing, pad printing, stencil printing, spraying, or squeegee printing; and Curing: The hydrofluoric acid resistant composition ink coated on the surface of the substrate is dried at a temperature of 50°C to 120°C for 3 to 30 minutes to form the protective layer.

24. The substrate processing method according to claim 22, characterized in that, When a hydrofluoric acid-resistant composition in dry film form is used, the step of applying the composition includes: Hot pressing: The hydrofluoric acid resistant dry film is hot-pressed onto the surface of the substrate at a temperature range of 70°C to 150°C and a pressure of not less than 0.4 MPa for 30 seconds to 5 minutes to form the protective layer.

25. The substrate processing method as described in claim 24, characterized in that, The bonding is performed under a vacuum of less than 0.1 MPa.

26. The substrate processing method according to claim 22, characterized in that, The etching process further includes: laser cutting the substrate before etching it with the hydrofluoric acid solution.

27. The substrate processing method according to claim 22, characterized in that, In the etching process, the concentration of the hydrofluoric acid solution is between 1% and 5%, and the immersion time lasts from 30 seconds to 30 minutes.

28. The substrate processing method according to claim 22, characterized in that, The stripping solvent is selected from at least one of water, N-methylpyrrolidone, methanol, ethanol, n-butanol, acetone, ethyl acetate, n-butyl ether, methyl tert-butyl ether, dimethyl phthalate, butanone, dimethyl sulfoxide, n-butyl ketone, cyclohexanone, toluene, and xylene.

29. The substrate processing method as described in claim 28, characterized in that, The stripping solvent also contains 0.5% to 3% by weight of surfactant.

30. The substrate processing method according to claim 22, characterized in that, The step of removing the protective layer is carried out in a temperature range between 20°C and 60°C.

31. The substrate processing method according to claim 22, characterized in that, The substrate is an ultra-thin glass with a thickness of no more than 70 micrometers.

32. A substrate, characterized in that, Prepared by the processing method of any one of claims 22 to 31.

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