Decorative ink for glass cover plate as well as preparation method and application of decorative ink

Abstract

The invention discloses decorative ink for a glass cover plate as well as a preparation method and application of the decorative ink. The component A comprises the following raw materials: a resin composition, an auxiliary agent and a solvent, the resin composition comprises polyurethane modified epoxy resin, silicone resin and polycarbonate diol resin, the silicone resin contains amino groups, and the weight part ratio of the polyurethane modified epoxy resin to the silicone resin to the polycarbonate diol resin in the resin composition is (1-5): (1-5): (1-5). According to the scheme, after the ink is dispensed and cured at an ultralow temperature (-88 DEG C), the shear force / area ratio (F / S value) of the ink breaks through 1.4, and the adhesive layer does not fall off. The ink always keeps excellent interface adhesion in a wide temperature range, effectively solves the industrial problems of insufficient shear strength and adhesive layer embrittlement and shedding of traditional ink in an extremely low temperature environment, and fills the material blank of ultra-low temperature shear performance ink for application equipment in alpine regions.

Description

Technical Field

[0001] The present invention relates to the technical field of inks, and particularly relates to a decorative ink for glass covers, a preparation method thereof, and an application thereof. Background Art

[0002] With the accelerating iteration of the consumer electronics industry towards high precision, lightweight, and environmental adaptability, the decorative ink coating for glass covers is facing the need for coordinated improvement of multi-dimensional performance indicators. In the field of precision devices such as mobile phones and smart watches, the transition of the substrate from traditional organic films to glass has triggered a paradigm shift in interface bonding characteristics: the surface energy of the organic substrate is relatively low, and good adhesion can be achieved through physical anchoring; while the high surface energy characteristics of the glass substrate require that the ink system simultaneously meet the dual requirements of dynamic flexibility and rigid anchoring, which poses a more complex structure-activity relationship challenge to the molecular design of the coating material. Especially under extreme low-temperature conditions (such as an environment of -88°C), the brittle phase transformation of materials and the thermal stress mismatch phenomenon are significantly aggravated, requiring the coating to simultaneously achieve the coordinated optimization of the anti-brittle fracture threshold and the mechanical stress buffering ability to ensure the structural integrity and aesthetic performance stability of the device in cold climate scenarios and low-temperature tests.

[0003] Currently, epoxy resins, polyurethane, or acrylic resin systems are generally used as ink bases in the industry, and high adhesion at room temperature (the F / S ratio in the pull-off force test is usually 1.0 - 1.3) and high wear resistance are achieved by adding curing agents, pigments, and additives. However, such traditional inks expose significant defects under ultra-low temperature conditions: firstly, the interfacial bonding strength between the resin matrix and the glass drops sharply at ultra-low temperatures, resulting in brittle fracture of the coating; secondly, the difference in the thermal expansion coefficients of the ink and substrates such as glass and metal is amplified at low temperatures, triggering internal stress concentration, and ultimately causing the coating to peel off from the substrate surface (the pull-off force F / S value is often lower than the industry safety threshold of 1.4). Such failure phenomena are particularly prominent in key parts such as the glass covers and metal middle frames of mobile phones and smart wearable devices, directly affecting the reliability and service life of the products.

[0004] In the prior art, although attempts have been made to improve the flexibility of the ink by plasticizer modification or introducing elastomeric components to reduce the incidence of the coating peeling off from the substrate surface, such solutions often come at the cost of coating hardness, and the method of simply increasing the crosslinking density to enhance adhesion instead exacerbates the low-temperature embrittlement tendency, forming a performance contradiction.

[0005] Therefore, there is an urgent need to develop a new type of ink system that can maintain stable high adhesion, and at the same time has a high pull-off force and is not easily detached even at ultra-low temperatures. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a decorative ink for glass covers, and this ink system has stable high adhesion, especially high pull-out force and is not easy to fall off even at ultra-low temperatures.

[0007] The present invention also provides a preparation method of the above-mentioned ink.

[0008] The present invention also provides an application of the above-mentioned ink.

[0009] According to one aspect of the present invention, there is provided a decorative ink for glass covers, including component A; the component A includes the following raw materials in parts by weight: 15-45 parts of a resin composition, 30-50 parts of a pigment, 3-8 parts of a filler, 3-8 parts of a curing agent, 5.5-12.5 parts of an auxiliary agent, and 6-22 parts of a solvent. The resin composition includes a polyurethane-modified epoxy resin, a silicone resin, and a polycarbonate diol resin (PCD). Among them, the silicone resin contains amino groups, and the weight ratio of the polyurethane-modified epoxy resin, the silicone resin, and the polycarbonate diol resin in the resin composition is 1-5:1-5:1-5.

[0010] The ink according to the embodiment of the present invention has at least the following beneficial effects: The present invention adopts an ink formula with three resins combined synergistically in a specific ratio. By optimizing the interfacial compatibility and the molecular chain segment movement ability between the resins, the wetting and dispersion effect of the resin on the powder is significantly enhanced, thereby constructing a uniform and dense paint film structure. After the ink of the present invention is dispensed and cured under ultra-low temperature conditions (-88 °C), the shear force / area ratio (F / S value) breaks through 1.4 and there is no phenomenon of glue layer peeling. At the same time, the ink always maintains excellent interfacial adhesion, effectively solving the industry problems of insufficient shear strength and brittle glue layer peeling of traditional low-temperature inks in extremely low-temperature environments. Especially for terminal devices using 8540 series adhesives for cover lamination, the solution of the present invention can significantly improve its structural reliability under ultra-low temperature working conditions, filling the material gap of inks with ultra-low temperature shear performance for application equipment in alpine regions, and providing an innovative solution for bonding schemes in extreme temperature environments. Compared with the prior art, the ink system of the present invention has the following technical advantages: 1) Extended processing window characteristics: Using the solution formula, the ink has a long activation period, which can better ensure the process stability of continuous printing operations.

[0011] 2) High hiding optical performance: When the ink of the present invention is applied, the optical density (OD value) is high, and the hiding effect is significantly improved compared with the traditional formula.

[0012] 3) Printing suitability of a single-component system: Excellent leveling property can be achieved without complex preparation, the printing effect is good, and the consistency of the continuous printing appearance is high, which can effectively meet the requirements of high-precision graphic reproduction.

[0013] 4) Multi-dimensional environmental tolerance: It has excellent chemical stability. At the same time, it also has good mechanical properties at extreme temperatures: it has high shear force and is not easy to fall off at ultra-low temperatures, and can still maintain high adhesion after thermal shock cycling.

[0014] According to some embodiments of the present invention, the weight ratio of the polyurethane-modified epoxy resin, silicone resin, and polycarbonate diol resin in the resin composition is 1-3:1-3:1-3.

[0015] According to some embodiments of the present invention, the polyurethane-modified epoxy resin has at least one of the following characteristics: 1) The glass transition temperature is 120-130 °C; 2) The epoxy equivalent is 170-250 g / eq.

[0016] According to some embodiments of the present invention, the polyurethane-modified epoxy resin has at least one of the following characteristics: 1) The glass transition temperature is 120-130 °C; 2) The epoxy equivalent is 195-220 g / eq; 3) The viscosity is 10000-16000 mPa·s (25 °C).

[0017] According to some embodiments of the present invention, the polyurethane-modified epoxy resin has at least one of the following characteristics: 1) The glass transition temperature is 120-130 °C; 2) The epoxy equivalent is 195-240 g / eq; 3) The viscosity is 10000-16000 mPa·s (25 °C).

[0018] According to some embodiments of the present invention, the polyurethane-modified epoxy resin includes NPER-133L produced by South Asia Company or HyPox UA10 produced by CVC Thermoset Specialties.

[0019] According to some embodiments of the present invention, the silicone resin has at least one of the following characteristics: 1) Amine equivalent: 250-270 g / NH; 2) The solid content ≥ 97%; 3) The kinematic viscosity is between 3500 ± 1000 cSt.

[0020] According to some embodiments of the present invention, the silicone resin includes DOWSIL™ 3055 of Dow.

[0021] According to some embodiments of the present invention, the polycarbonate diol resin has at least one of the following characteristics: 1) The hydroxyl value is between 50 and 65 KOH / g; 2) The solid content is ≥ 97%; 3) The pencil hardness after curing is < F, and the test condition is a force of 300 g.

[0022] According to some embodiments of the present invention, the polycarbonate diol resin has at least one of the following characteristics: 1) The hydroxyl value is between 50 and 60 KOH / g; 2) The solid content is ≥ 97%; 3) The pencil hardness after curing is < F, and the test condition is a force of 300 g.

[0023] The addition of polycarbonate diol resins such as T5652 effectively improves the flexibility of the paint film under ultra-low temperature conditions.

[0024] According to some embodiments of the present invention, the polycarbonate diol resin includes the T5652 polycarbonate diol resin produced by Asahi Kasei Corporation.

[0025] According to some embodiments of the present invention, the mass ratio of the resin composition in the raw materials of component A is 15 - 45%.

[0026] According to some embodiments of the present invention, component A includes the following raw materials in parts by weight: 15 - 45 parts of resin composition, 41.5 - 78.5 parts of auxiliary agent, and 6 - 22 parts of solvent.

[0027] According to some embodiments of the present invention, the auxiliary agent includes a curing agent, and the curing agent includes blocked isocyanate. By adding blocked isocyanate, the activation period time is effectively increased, and the appearance effect of the ink will not be affected by the curing degree during the printing process. The curing reaction of polyurethane-modified epoxy resin and silicone resin provides the main structure. Since the epoxy activity modified by polyurethane and the amine value-modified activity of silicone resin do not react at room temperature and react rapidly at 150°C, the polycarbonate diol resin with hydroxyl value and blocked isocyanate curing agent (such as DESMODUR BL 3175A) can also achieve no reaction at room temperature and rapid reaction at 150°C to adjust the activation period, realizing the balance of "long activation period and rapid curing".

[0028] According to some embodiments of the present invention, the curing agent includes at least one of DESMODUR BL 3175A produced by Covestro, SBN-70D of Asahi Kasei, or DB-85121 with double bonds.

[0029] According to some embodiments of the present invention, the curing agent includes DESMODUR BL 3175A produced by Covestro. DESMODUR BL 3175A is a blocked HDI curing agent.

[0030] According to some embodiments of the present invention, the mass ratio of the curing agent in the raw materials of component A is 3-8%.

[0031] According to some embodiments of the present invention, the additives include pigments and fillers.

[0032] According to some embodiments of the present invention, the pigment includes white pigment.

[0033] According to some embodiments of the present invention, the pigment includes at least one of titanium dioxide, zinc white or lithopone. It can also be other white pigments (such as lead white, antimony white or other organic white pigments, etc.), or other color pigments can be selected according to needs.

[0034] According to some embodiments of the present invention, the median particle size of the pigment is below 0.25 μm. By controlling the median particle size of the pigment within this range, the high requirements for the optical density (OD value) of high-whiteness products can be more effectively met. When the median particle size is above 0.3 μm, the OD value is below 2, which can meet the requirements of ordinary products.

[0035] According to some embodiments of the present invention, the median particle size of the pigment is between 0.15 and 0.22 μm.

[0036] According to some embodiments of the present invention, the median particle size of the pigment is between 0.18 and 0.2 μm.

[0037] According to some embodiments of the present invention, the median particle size of the pigment is between 0.19 ± 0.002 μm.

[0038] When the median particle size is within this level range, it can not only better ensure the OD value of the ink layer, but also better ensure the hiding power.

[0039] According to some embodiments of the present invention, the filler includes at least one of barium sulfate, calcium carbonate, talc, kaolin or mica powder.

[0040] According to some embodiments of the present invention, the particle size of the filler is at the nanoscale.

[0041] Using ultrafine pigments and synchronously adding nanoscale fillers to effectively fill the gaps between the nanoscale fillers, reducing the voids between the powder materials in the paint film to form a dense paint film, which can synergistically improve the OD value of the ink layer.

[0042] According to some embodiments of the present invention, the sum of the masses of the pigment and the filler accounts for 33-58% by mass in the raw materials of Component A.

[0043] According to some embodiments of the present invention, the pigment accounts for 30-50% by mass in the raw materials of Component A.

[0044] According to some embodiments of the present invention, the filler accounts for 3-8% by mass in the raw materials of Component A.

[0045] According to some embodiments of the present invention, the solvent includes at least one of ester solvents and ketone solvents.

[0046] According to some embodiments of the present invention, the ester solvents include at least one of PMA (propylene glycol methyl ether acetate), ethyl acetate, butyl acetate, dimethyl carbonate (DMC), diethyl carbonate, dibutyl carbonate, diisopropyl carbonate, or dibasic ester (DBE).

[0047] According to some embodiments of the present invention, the ketone solvents include at least one of methyl isobutyl ketone and isophorone.

[0048] According to some embodiments of the present invention, the solvent includes at least one of PMA (propylene glycol methyl ether acetate), DBE (dibasic ester), and isophorone.

[0049] According to some embodiments of the present invention, the additives include at least one of a dispersant, an antifoaming agent, a rheology additive, and a leveling agent.

[0050] According to some embodiments of the present invention, the additives include a dispersant, an antifoaming agent, a rheology additive, and a leveling agent.

[0051] According to some embodiments of the present invention, the additives include the following raw materials in parts by weight: 4-8 parts of a dispersant, 0.5-2 parts of an antifoaming agent, 0.5-1.5 parts of a rheology additive, and 0.5-1 part of a leveling agent. One part in the parts by weight of the additives is equal to the amount represented by one part of the other raw materials in Component A.

[0052] According to some embodiments of the present invention, the dispersant includes at least one of BYK 161, BYK 110, BYK 163 produced by BYK Chemie GmbH, or TEGO 710 produced by Evonik Industries AG.

[0053] According to some embodiments of the present invention, the dispersant includes BYK 161 produced by BYK Chemie GmbH. BYK 161 is a high molecular weight additive of BYK company that deflocculates pigments through steric hindrance; this dispersant has an efficient dispersing effect on pigments and has no influence on the adhesion of the paint film to glass.

[0054] According to some embodiments of the present invention, the defoamer comprises at least one of BYK 011, BYK 052 or BYK 066N produced by BYK Chemie.

[0055] According to some embodiments of the present invention, the defoamer comprises BYK 011 produced by BYK Chemie. The defoamer BYK011 is a silicone-free and highly effective defoamer that can effectively improve the problem of film bubbles during printing.

[0056] According to some embodiments of the present invention, the rheology additive is at least one of polyamide wax HPA 202 or organobentonite.

[0057] According to some embodiments of the present invention, the rheology additive is Claytone APA bentonite produced by Lockwood Chemical Co., USA. The addition of bentonite effectively improves the grinding efficiency, enabling the nano barium sulfate BF-20 to be easily dispersed to ≤10μm.

[0058] According to some embodiments of the present invention, the leveling agent comprises a polyether-modified silicone-based leveling agent.

[0059] According to some embodiments of the present invention, the leveling agent comprises BYK 333 produced by BYK Chemie. BYK 333 is a leveling agent of the polyether-modified polydimethylsiloxane solution type that can effectively improve the film and strongly reduce the surface tension; it has excellent substrate wetting ability, prevents cratering and increases surface smoothness.

[0060] According to some embodiments of the present invention, the ink further comprises component B which includes a coupling agent.

[0061] According to some embodiments of the present invention, the mass ratio of component B to component A is 2-4:100.

[0062] According to some embodiments of the present invention, the coupling agent is a silane coupling agent.

[0063] According to some embodiments of the present invention, the coupling agent comprises at least one of glycidyl alkyltrialkoxysilane, 3,4-cyclohexyl epoxy alkyltrialkoxysilane, aminosiloxane, Dow Corning coupling agents Z-6040, Z-6030, Z-6020 and Z-6011.

[0064] According to some embodiments of the present invention, the coupling agent is an epoxy-based silane coupling agent.

[0065] According to some embodiments of the present invention, the coupling agent comprises Dow Corning coupling agent Z-6040.

[0066] According to some embodiments of the present invention, the ink further comprises Component C, and Component C comprises a diluent.

[0067] According to some embodiments of the present invention, the diluent comprises at least one of No. 200 solvent oil produced by Hubei Taihechang Chemical Industry, alcohol ether diluents, aliphatic hydrocarbons, xylene, n-butanol, or US-2 solvent produced by Sherwin-Williams.

[0068] According to some embodiments of the present invention, the diluent comprises No. 200 solvent oil. The No. 200 solvent oil is super slow-drying and non-polar. Using this diluent can make the viscosity of the ink more stable. At the same time, this diluent has a low odor and is easily acceptable to production employees.

[0069] According to some embodiments of the present invention, the mass ratio of Component C to Component A is 5 - 15:100.

[0070] According to some embodiments of the present invention, the ink comprises 100 parts by weight of Component A, 2 - 4 parts by weight of Component B, and 5 - 15 parts by weight of Component C; wherein, the additives include a dispersant, an antifoaming agent, a rheology aid, and a leveling agent. Component A comprises raw materials in the following parts by weight: 15 - 45 parts of a resin composition, 30 - 50 parts of a pigment, 3 - 8 parts of a filler, 3 - 8 parts of a curing agent, 4 - 8 parts of a dispersant, 0.5 - 2 parts of an antifoaming agent, 0.5 - 1.5 parts of a rheology aid, 0.5 - 1 part of a leveling agent, and 6 - 22 parts of a solvent. The resin composition comprises a polyurethane-modified epoxy resin, a silicone resin, and a polycarbonate diol resin; the pigment comprises a white pigment; the dispersant comprises BYK 161; the antifoaming agent comprises BYK 011; the rheology aid comprises Claytone APA bentonite; the leveling agent comprises BYK 333; Component B comprises a coupling agent; Component C comprises a diluent, and the diluent comprises No. 200 solvent oil.

[0071] The ink formulation of the present invention constructs a high-performance ink system through the synergistic effect of multiple components. By the synergistic compatibility of polyurethane-modified epoxy resin, silicone resin, and polycarbonate diol resin, the adhesion performance of the ink is significantly improved. The introduction of polycarbonate diol resin (PCD) as a flexible segment regulator significantly enhances the flexibility of the paint film under ultra-low temperature conditions, effectively avoiding cracking at low temperatures. Through the synergistic cooperation of the resin composition and the powder particle size, the OD value is significantly increased. At the same time, a blocked isocyanate curing agent is used to maintain a stable single-component state at room temperature, and the activation period is extended to more than 24 hours. This system avoids premature crosslinking of the prepolymer during printing, ensuring decoupled control of the ink leveling property and the final curing degree, and preventing the appearance of the ink from being affected by the curing degree during printing. In addition, by using a synergistic system of silicone leveling agent and silicone-free defoamer, problems such as oil scattering and bubbles during the printing of the paint film are effectively improved, enabling the paint film to be more evenly distributed on the surface of the substrate. An environmentally friendly diluent system - 200# solvent oil subjected to deep hydrogenation treatment - can effectively stabilize the ink viscosity and significantly reduce the VOC emissions compared to the traditional system, meeting the requirements of environmentally friendly production. The low odor characteristic makes it more acceptable to employees and is beneficial to improving production efficiency.

[0072] According to another aspect of the present invention, a method for preparing the decorative ink for the glass cover plate is provided. The additives include a dispersant, a defoamer, a rheology aid, and a leveling agent, and the solvents include ester solvents and ketone solvents; The preparation method includes the following steps: S1. Mix the polyurethane-modified epoxy resin with an ester solvent to obtain Mixture I; S2. Add silicone resin, polycarbonate diol resin, dispersant, pigment, filler, and rheology aid to the Mixture I to obtain Mixture II; S3. Add a curing agent, a defoamer, a ketone solvent, and a leveling agent to the Mixture II to obtain the ink.

[0073] According to some embodiments of the present invention, the step S1 further includes a step of stirring under heating.

[0074] According to some embodiments of the present invention, the mixing conditions of the step S1 include: 1) The temperature is below 60°C; 2) Stir at 800 rpm to 1000 rpm for 30 to 60 minutes.

[0075] When the resin and the solvent are stirred and dissolved into each other, heat is generated during stirring. Therefore, monitor the temperature during dissolution. If the temperature is too high, more solvent will volatilize, affecting the dissolution efficiency.

[0076] According to some embodiments of the present invention, the step S1 further includes a step of cooling the mixture I to below 40°C.

[0077] According to some embodiments of the present invention, the step S2 further includes, after adding silicone resin, polycarbonate diol resin, dispersant, pigment, filler and rheological aid, stirring at 600 - 800 rpm for 20 - 30 minutes and standing for more than 12 hours.

[0078] According to some embodiments of the present invention, the step S2 further includes a step of grinding the mixture II.

[0079] According to some embodiments of the present invention, the grinding treatment is used to control the fineness of the mixture II to below 10 μm.

[0080] According to some embodiments of the present invention, the grinding treatment is carried out using a three - roll mill or a high - viscosity sand mill.

[0081] According to some embodiments of the present invention, the ink further includes components B and C, and the preparation method further includes measuring components B and C and mixing them in proportion.

[0082] According to some embodiments of the present invention, the mass ratio of component B to component A is 2 - 4:100.

[0083] According to some embodiments of the present invention, the mass ratio of component C to component A is 5 - 15:100.

[0084] According to some embodiments of the present invention, component B includes a coupling agent and component C includes a diluent.

[0085] According to another aspect of the present invention, a glass cover plate is provided, which includes a glass cover plate body and a covering ink layer arranged in a stacked manner, and the covering ink layer is prepared from the above - mentioned ink.

[0086] According to some embodiments of the present invention, the glass cover plate body is 2D glass or 2.5D glass.

[0087] According to some embodiments of the present invention, the glass cover plate body includes an edge area, and the covering ink layer is located in the edge area.

[0088] According to yet another aspect of the present invention, a terminal device is provided, which includes a first housing member and a second housing member. The first housing member and the second housing member are connected by an adhesive, and a covering ink layer is provided between the adhesive and the first housing member or between the adhesive and the second housing member, and the covering ink layer is prepared from the above - mentioned ink.

[0089] According to some embodiments of the present invention, the first housing member and / or the second housing member is a glass cover plate.

[0090] According to some embodiments of the present invention, the glass cover plate includes a glass cover plate body and the covering ink layer arranged in a stacked manner, the glass cover plate body includes an edge region, and the covering ink layer is located in the edge region.

[0091] According to some embodiments of the present invention, the terminal device includes a mobile phone or a smart wearable device.

[0092] According to some embodiments of the present invention, the smart wearable device includes a smart watch.

[0093] According to some embodiments of the present invention, the adhesive includes glue.

[0094] According to some embodiments of the present invention, the adhesive includes ethyl cyanoacrylate glue.

[0095] According to some embodiments of the present invention, the adhesive includes 8540 glue.

[0096] According to some embodiments of the present invention, the covering ink layer is printed on the glass cover plate by a screen printing process.

[0097] According to some embodiments of the present invention, the first housing member is a glass cover plate, the glass cover plate includes a glass cover plate body and the covering ink layer, the glass cover plate body includes a main body region and an edge region, and the first housing member is connected to the second housing member through the edge region.

[0098] According to some embodiments of the present invention, the terminal device includes functional components, the first housing member and the second housing member are connected by an adhesive to form an accommodation space, and the functional components are located in the accommodation space.

[0099] According to some embodiments of the present invention, the first housing member includes a middle frame, and the second housing member includes a glass cover plate. The glass cover plate can be fixed to the middle frame to install functional components such as a display screen on the middle frame.

[0100] The solution of the present invention is particularly applicable to various white glass front cover plates that are bonded with 8540 glue and other glues and have high shear force requirements under ultra-low temperature conditions.

[0101] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Detailed embodiments

[0102] The following will clearly and completely describe the concept of the present invention and the technical effects produced in combination with embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts all belong to the scope protected by the present invention. The test methods used in the embodiments are all conventional methods unless otherwise specified; the materials, reagents, etc. used are all reagents and materials that can be obtained from commercial channels unless otherwise specified. Unless otherwise specified, the same parameter values are taken in each embodiment. The embodiments described below are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0103] In the description of the present invention, the description referring to terms such as "some embodiments" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0104] In the description of the present invention, if there is a description of I, II, etc., it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence of the indicated technical features.

[0105] Two-dimensional planar glass cover plate (2D Glass Cover Plate): It refers to a glass cover plate assembly designed with a pure planar geometric shape, with an infinite surface curvature radius and no any arc processing features. The standard processing process chain of this type of cover plate includes: substrate cutting (Blanking) - precision CNC carving (Fine Milling) - functional hole processing (Hole Drilling) - surface polishing treatment (Polishing) - chemical strengthening process (Chemical Strengthening) - silk-screen printing decoration (Silk-screen Printing) - surface coating treatment (Coating).

[0106] 2.5D Glass Cover Plate: It refers to a composite structure with a combination of a central planar area and a peripheral arc transition area, and the edge radius of curvature is usually controlled in the range of 0.5 - 2.0 mm. Compared with the 2D glass cover plate, the processing technology adds edge numerical control grinding and curved surface polishing in the basic process. This structure is widely used in the touch panels of intelligent terminal devices (such as smart phones, smart watches, etc.), combining the stability of plane display and the comfort of edge operation.

[0107] Silk-screen Printing Technology: A printing method based on the principle of ink penetration through the patterns on the screen plate. The system consists of five major elements: a screen frame, a photosensitive emulsion plate-making layer, a squeegee, a printing table, and a substrate. During printing, a constant pressure is applied to the screen plate by the squeegee, so that the ink passes through the mesh holes in the pattern area and is transferred to the surface of the substrate to achieve precise graphic replication. This technology is suitable for decorative printing on hard substrates such as glass and ceramics.

[0108] HD8540 Instant Adhesive: Also known as "8540 glue", chemically named ethyl cyanoacrylate-based fast-curing adhesive, which is composed of monomers, plasticizers, inhibitors, and stabilizers. It has the characteristics of rapid curing at room temperature, high bonding strength, and good transparency, and is suitable for structural bonding of substrates such as glass, metal, and plastic, especially for the temporary fixation and permanent encapsulation of precision electronic devices.

[0109] Low-temperature pulling force: The glass substrate printed with ink is adhesively bonded by HD8540 glue and subjected to a shear force test under low-temperature environmental conditions. Record the ratio of the failure load (F) to the bonding area (S) (F / S), and observe the proportion of the ink layer peeling area to comprehensively evaluate the low-temperature mechanical properties of the bonding system.

[0110] The information of the reagent manufacturers used in the following examples and comparative examples is shown in Table 1 below: Table 1

[0111] Examples 1 - 8 This example provides a decorative ink for a glass cover plate resistant to ultra-low temperatures, and its formula is shown in Table 2 below: Table 2

[0112] Comparative Examples 1 - 6 This example provides a decorative ink for glass covers, and its formula is shown in Table 3 below: Table 3

[0113] The ink preparation processes in the above Examples 1-8 and Comparative Examples 1-6 are as follows: 1) Sequentially add Resin 1, PMA, and DBE to the ink reactor, stir at 900 r / min for 45 minutes (temperature controlled below 60°C); after confirming that there is no obvious granular liquid resin, stop stirring and cool to below 40°C.

[0114] 2) On the basis of Step 1, add the corresponding proportions of Resin 2, Resin 3, BYK161, CR-828, BF-20, and Claytone APA bentonite, stir at 700 r / min for 25 minutes, let stand for more than 12 hours, and put into a three-roll mill or a high-viscosity sand mill for grinding; the number of grinding passes and grinding time are determined according to the fineness ground out. When the grinding fineness is below 10 μm, take it out.

[0115] 3) On the basis of Step 2, add the corresponding proportions of DESMODUR BL 3175A, BYK011, isophorone, and BYK-333, stir at 700 r / min for 25 minutes to obtain Component A.

[0116] 4) Weigh Components B and C in proportion to obtain it.

[0117] The ink application processes in the above Examples 1-8 and Comparative Examples 1-6 are as follows: Take glass from the same source as the material, and form a coating on the glass through the following operations: Use a 250-mesh screen for 4-layer printing, 7-9 μm for each printing. For the first three printings, after each printing, bake at 150°C for 5 minutes; after the last printing, bake at 150°C for 30 minutes.

[0118] Performance testing: Take the coating prepared by the above operations for performance testing. The methods and instruments used in the testing process are described as follows: 1. Film thickness testing instrument: Mitutoyo micrometer for thin sheets No. 293-240-30, Japan.

[0119] 2. The OD value testing instrument is Linshang LS117. Test according to the instruction manual. After turning on the machine, directly place it on the testing machine table and read the data.

[0120] 3. The adhesion test refers to the 7-grid method in GB / T 13217.7-2023 "Test Method for Ink Adhesion".

[0121] 4. The test method for pencil hardness with a 300 g force shall be carried out according to Method A of GB / T 6739-2022 "Paints and varnishes - Determination of film hardness by pencil test".

[0122] 5. Low-temperature shear force test method: On the already prepared sample plate, mix the AB glue of 8540 glue evenly and then apply the glue. Then, cover it with the same glass material printed with ink, and then press a 50 g weight on it. Place it in an oven at 60 °C and bake for 20 minutes; take out the sample plate, place the glass vertically in a cryogenic (-88 °C) shear force device to measure the breaking force. After completion, calculate the size of the glue application area and obtain F / S.

[0123] The test results of the samples prepared from the ink of the examples and comparative examples are shown in Tables 4 and 5 as follows: Table 4

[0124] Table 5

[0125] * Note: The test standards for OD values in Tables 4 and 5 only represent the OD value standards of some high whiteness products.

[0126] In addition, it has been verified that for the ink of the embodiment scheme of the present invention, at 0 hour, 4 hours, 8 hours, 16 hours, and 24 hours after preparation, when printing a four-layer sample plate, the cross-cut and boiling cross-cut tests are all below grade 1, and the shear force F / S at ultra-low temperature is all 1.5. This shows that the activation period of the ink of the present invention scheme is more than 24 hours.

[0127] As can be seen from Tables 4 and 5, when only one or two of epoxy resin modified with polyurethane resin, silicone resin, or polycarbonate diol resin are used, the problems of ultra-low temperature resistance, high draw force, and high adhesion cannot be solved simultaneously. When only epoxy resin modified with polyurethane resin and silicone resin are added, it is easy to fall off under ultra-low temperature and high draw force, while the ink prepared from the resin system containing only polycarbonate diol resin or containing both polycarbonate diol resin and silicone resin has weak adhesion.

[0128] In the resin composition of the present invention's solution, the epoxy groups in the polyurethane-modified epoxy resin can provide a high crosslinking density, enhancing hardness and chemical resistance. Among them, the urethane bond (-NHCOO-) in the polyurethane segment alleviates the brittleness of the epoxy resin and improves flexibility; the silicone resin with amine groups contains amine functional groups that undergo a ring-opening reaction with the epoxy groups of the epoxy resin, enhancing the interfacial crosslinking density and adhesion. The Si-O-Si groups therein have excellent high-temperature resistance and low surface energy, improving the stability of the paint film under extreme temperatures. The flexible carbonate long chains in the polycarbonate diol resin provide the movement ability of the molecular chains, preventing embrittlement at low temperatures and alleviating thermal stress at high temperatures. At ultra-low temperatures (-88°C), the flexible chain segments of PCD absorb external forces through molecular chain slip, avoiding cracking of the paint film; the siloxane chain segments of the silicone resin reduce the low-temperature shrinkage stress; the epoxy resin provides sufficient crosslinking density to maintain structural integrity. Through the synergistic effect of the three resins, the performance boundaries of single resin or two resins in terms of temperature resistance, flexibility, adhesion, etc. are broken through, and finally multiple advantages such as high adhesion and high ultra-low temperature pulling force are achieved.

[0129] In summary, the present invention adopts an ink formulation with a synergistic combination of three resins. By optimizing the interfacial compatibility and molecular chain segment movement ability between the resins, the wetting and dispersion effect of the resin on the powder material is significantly enhanced, thereby constructing a uniform and dense paint film structure. Compared with traditional single or two-component resin-based inks, the technical solution of the present invention exhibits the following technical advantages: 1) Breakthrough in activation period regulation: The resin synergistic system effectively delays the crosslinking and curing reaction process of the ink, enabling the system to maintain a stable processing window for 24 hours, with stable ink viscosity, ensuring that the construction performance is not affected by time.

[0130] 2) Improvement in covering efficiency: Through the multiple wrapping and orientation arrangement of the resin on the pigment particles, an excellent covering performance with an OD value ≥ 2.2 can be achieved at a dry film thickness of 30 μm, reducing the coating process by 2 - 3 layers compared to the conventional system.

[0131] 3) Optimization of printing suitability: The single-component system maintains a constant rheology during continuous printing, ensuring that the surface gloss, DOI, and film thickness uniformity of the printed product are always consistent.

[0132] 4) Innovation in grinding efficiency: The layered structure of bentonite produces a peeling effect under the action of shear force, and its nanoscale interlayer domain provides a dispersion channel for BF-20 nanobarium sulfate, enabling the particle size to be stably controlled at ≤ 10 μm, significantly reducing the grinding energy consumption.

[0133] 5) Resistance to medium erosion: The paint film of the present invention's solution has excellent barrier properties against chemical media such as acids, alkalis, and solvents.

[0134] 6) Low-temperature rheological properties: In an ultra-low temperature environment, the synergistic cooperation between resin compositions enables the ink to have both high shear force and ensures that it is not easily detached.

[0135] 7) Stable adhesion: It has good adhesion within a wide temperature range.

[0136] 8) Good flexibility: Even at ultra-low temperatures, the paint film of the solution of the present invention still has good flexibility.

[0137] 9) Environmental protection: The characteristic of low odor, higher acceptance by employees, more environmentally friendly and more conducive to improving production efficiency.

[0138] The above has made a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the purpose of the present invention.

Claims

1. A decorative ink for a glass cover plate, characterized in that: The invention comprises component A; the component A comprises the following raw materials in parts by weight: 15 to 45 parts of a resin composition, 30 to 50 parts of a pigment, 3 to 8 parts of a filler, 3 to 8 parts of a curing agent, 5.5 to 12.5 parts of an auxiliary agent and 6 to 22 parts of a solvent; the resin composition comprises a polyurethane-modified epoxy resin, a silicone resin and a polycarbonate diol resin, wherein the silicone resin contains an amine group; and the weight ratio of the polyurethane-modified epoxy resin, the silicone resin and the polycarbonate diol resin in the resin composition is 1 to 5:1 to 5:1 to 5.

2. The decorative ink for glass cover according to claim 1, characterized in that: The polyurethane modified epoxy resin has at least one of the following characteristics: 1) a glass transition temperature of 120-130° C.; 2) an epoxy equivalent of 170-250 g / eq; The silicone resin has at least one of the following properties: 1) Amine equivalent: 250-270 g / NH; 2) Solid content ≥ 97%; 3) Kinematic viscosity between 3500±1000 cSt; The polycarbonate diol resin has at least one of the following characteristics: 1) Hydroxyl value is between 50~65KOH / g; 2) Solid content ≥97%; 3) Pencil hardness after curing is <F, and the test condition is 300g force.

3. The decorative ink for glass cover according to claim 1, characterized in that: The polyurethane modified epoxy resin includes NPER-133L produced by Nan Ya Corporation or HyPox UA10 produced by CVC Thermosetting Special Materials Division; and / or, the silicone resin includes DOWSIL™3055 produced by Dow Chemical Company; and / or, the polycarbonate diol resin includes T5652 polycarbonate diol resin produced by Asahi Kasei Corporation.

4. The decorative ink for glass cover according to claim 1, characterized in that: The curing agent includes blocked isocyanate.

5. The decorative ink for glass cover according to claim 1, characterized in that: The median particle size of the pigment is between 0.15 and 0.22 μm.

6. The decorative ink for glass cover according to any one of claims 1 to 5, characterized in that: The ink comprises 100 parts by weight of component A, 2-4 parts by weight of component B and 5-15 parts by weight of component C; wherein the additives comprise a dispersant, a defoamer, a rheological additive and a leveling agent, the component A comprises the following raw materials in parts by weight: 15-45 parts of a resin composition, 30-50 parts of a pigment, 3-8 parts of a filler, 3-8 parts of a curing agent, 4-8 parts of a dispersant, 0.5-2 parts of a defoamer, 0.5-1.5 parts of a rheological additive, 0.5-1 parts of a leveling agent and 6-22 parts of a solvent, the resin composition comprises a polyurethane-modified epoxy resin, a silicone resin and a polycarbonate diol resin; the pigment comprises a white pigment; the dispersant comprises BYK 161; the defoamer comprises BYK011, and the leveling agent comprises BYK 333; the rheological additive comprises Claytone APA bentonite; the component B comprises a coupling agent; the component C comprises a diluent, and the diluent comprises 200# solvent oil.

7. A method for preparing the decorative ink for a glass cover plate according to any one of claims 1 to 5, characterized in that: The additives include dispersants, defoamers, rheological additives and leveling agents, and the solvents include ester solvents and ketone solvents; The preparation method comprises the following steps: S1, mixing a polyurethane-modified epoxy resin with an ester solvent to obtain a mixture I; S2, adding silicone resin, polycarbonate diol resin, dispersant, pigment, filler and rheological additive to the mixture I to obtain a mixture II; S3, adding a curing agent, a defoaming agent, a ketone solvent and a leveling agent into the mixture II to obtain.

8. A glass cover plate, characterized in that: The invention comprises a stacked glass cover plate body and a covering ink layer, wherein the covering ink layer is prepared by using the decorative ink for the glass cover plate according to any one of claims 1 to 6.

9. A terminal device, characterized in that: The invention comprises a first shell member and a second shell member, wherein the first shell member and the second shell member are connected by an adhesive, and a covering ink layer is provided between the adhesive and the first shell member or between the adhesive and the second shell member, and the covering ink layer is prepared by using the decorative ink for the glass cover plate according to any one of claims 1 to 6.

10. The terminal device according to claim 9, characterized in that: The first shell member and / or the second shell member is a glass cover plate, the glass cover plate comprises a glass cover plate body and the covering ink layer which are stacked, the glass cover plate body comprises an edge region, and the covering ink layer is located in the edge region.

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