High-glossiness environment-friendly ultraviolet curing printing ink for trivalent chromium surface, product and preparation method of high-glossiness environment-friendly ultraviolet curing printing ink

Abstract

The invention relates to ultraviolet curing ink for a high-glossiness environment-friendly trivalent chromium surface, a product and a preparation method of the ultraviolet curing ink. The ultraviolet curing ink is prepared from the following raw materials in parts by mass: 35 to 45 parts of polyurethane acrylate resin, 15 to 30 parts of epoxy acrylate resin, 10 to 20 parts of glycol diacrylate, 5 to 10 parts of phosphate acrylate, 3 to 8 parts of polyvinyl butyral and 3 to 5 parts of a photoinitiator. The ultraviolet curing ink is applied to the surface of an environment-friendly trivalent chromium electroplating product and has good adhesive force and wear resistance.

Description

Technical Field

[0001] This application relates to the field of ink materials, and in particular to high-gloss environmentally friendly trivalent chromium surface UV-curable inks, products and their preparation methods. Background Technology

[0002] As an important component of modern homes and commercial spaces, bathroom hardware products have a huge global market size and maintain stable growth. Products in this industry, such as faucets, showerheads, and bathroom accessories, have long relied heavily on hexavalent chromium (Cr(VI)) electroplating to achieve their classic wear-resistant and corrosion-resistant appearance. However, hexavalent chromium pollution is extremely serious; the concentration of chromium in electroplating wastewater can reach as high as 9.2 mg / L. Hexavalent chromium is an internationally recognized potent carcinogen and mutagen, with a toxicity approximately 100 times that of trivalent chromium, posing serious harm to human skin, respiratory system, and internal organs. More importantly, its wastewater and residue are difficult to degrade naturally in the environment, can remain for a long time, and can seep into and pollute soil and groundwater, creating persistent environmental risks.

[0003] Replacing hexavalent chromium with trivalent chromium (Cr(III)) electroplating is currently the industry's primary green transformation path. Trivalent chromium is environmentally friendly, and its plating also provides excellent surface finishes with high gloss and corrosion resistance.

[0004] However, this high-gloss, high-density surface presents new technical challenges: its extremely low surface energy makes it a typical substrate that is difficult to adhere to. Conventional inks, including some general-purpose UV inks, are prone to poor adhesion and peeling on this surface. Moreover, the industry currently widely uses thermosetting (baking) inks for coating, which consumes a lot of energy and requires a long baking time. For example, patent (CN111087847A) mentions that it needs to be baked at 150°C for 15 minutes. In addition, thermosetting uses a semi-open flat oven, which results in a large amount of heat loss and extremely high power consumption. The oven length is usually between 6 and 20 meters, occupying a huge amount of production space. Its inherent defects are amplified under the current pressure of energy conservation and emission reduction. Summary of the Invention

[0005] Based on this, one aspect of this application provides a high-gloss, environmentally friendly trivalent chromium surface UV-curable ink, which, when applied to the surface of environmentally friendly trivalent chromium electroplated products, exhibits good adhesion and abrasion resistance.

[0006] In addition, other aspects of this application also provide an article and a method for preparing the same.

[0007] A high-gloss, environmentally friendly trivalent chromium surface UV-curable ink, wherein the raw materials for preparing the UV-curable ink, by weight, include: 35-45 parts of polyurethane acrylate resin, 15-30 parts of epoxy acrylate resin, 10-20 parts of glycol diacrylate, 5-10 parts of phosphate acrylate, 3-8 parts of polyvinyl butyral, and 3-5 parts of photoinitiator.

[0008] Optionally, the diol diacrylate includes one or more of hexanediol diacrylate, neopentyl glycol diacrylate, and polyethylene glycol diacrylate.

[0009] Optionally, the phosphate ester acrylate includes one or more of methacryloyloxyethyl phosphate and 2-hydroxyethyl methacrylate phosphate.

[0010] Optionally, the photoinitiator includes one or more of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 2-isopropylthioxanthone, and 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide.

[0011] Optionally, the photoinitiator comprises 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0012] Optionally, the raw materials for preparing the UV-curable ink, by weight, include: 40-45 parts of polyurethane acrylate resin, 15-20 parts of epoxy acrylate resin, 10-20 parts of glycol diacrylate, 5-10 parts of phosphate acrylate, 5-8 parts of polyvinyl butyral, and 4-5 parts of photoinitiator; or,

[0013] The raw materials for preparing the UV-curable ink, by weight, include: 35 parts polyurethane acrylate resin, 30 parts epoxy acrylate resin, 5 parts methacryloyloxyethyl phosphate, 10 parts hexanediol diacrylate, 3 parts polyvinyl butyral, and 3 parts photoinitiator; or,

[0014] The raw materials for preparing the UV-curable ink, by weight, include: 35 parts polyurethane acrylate resin, 30 parts epoxy acrylate resin, 10 parts methacryloyloxyethyl phosphate, 20 parts hexanediol diacrylate, 3 parts polyvinyl butyral, and 3 parts photoinitiator; or,

[0015] The raw materials for preparing the UV-curable ink, by weight, include: 40 parts polyurethane acrylate resin, 20 parts epoxy acrylate resin, 8 parts methacryloyloxyethyl phosphate, 15 parts hexanediol diacrylate, 5 parts polyvinyl butyral, and 4 parts photoinitiator; or,

[0016] The raw materials for preparing the UV-curable ink, by weight, include: 45 parts polyurethane acrylate resin, 15 parts epoxy acrylate resin, 5 parts methacryloyloxyethyl phosphate, 10 parts hexanediol diacrylate, 8 parts polyvinyl butyral, and 5 parts photoinitiator; or,

[0017] The raw materials for preparing the UV-curable ink, by weight, include: 45 parts of polyurethane acrylate resin, 15 parts of epoxy acrylate resin, 10 parts of methacryloyloxyethyl phosphate, 20 parts of hexanediol diacrylate, 8 parts of polyvinyl butyral, and 5 parts of photoinitiator.

[0018] Optionally, the raw materials for preparing the UV-curable ink, by weight, further include: 1 to 2 parts of silane coupling agent; and / or,

[0019] The raw materials for preparing the UV-curable ink, by weight, also include: 0.2 to 0.5 parts of wetting agent and 3 to 10 parts of color ink.

[0020] An article includes: a substrate and an ink layer disposed on the surface of the substrate, the ink layer being obtained by curing with the above-mentioned high-gloss environmentally friendly trivalent chromium surface UV-curable ink.

[0021] Optionally, the article further includes an environmentally friendly trivalent chromium electroplating layer disposed between the substrate and the ink layer.

[0022] Optionally, the thickness of the ink layer is 10 μm to 20 μm; and / or,

[0023] The environmentally friendly trivalent chromium electroplated layer has a gloss level of ≥500 GU when measured at a 60° angle; and / or,

[0024] The environmentally friendly trivalent chromium electroplating layer has a roughness Ra ≤ 0.1 μm and a roughness Rz ≤ 0.05 μm; and / or,

[0025] The products include hardware products or bathroom products.

[0026] A method for preparing an article includes the following steps:

[0027] UV-curable ink is applied to the surface of a substrate and then cured using UV light to obtain the product.

[0028] The UV-curable ink is the aforementioned high-gloss, environmentally friendly trivalent chromium surface UV-curable ink.

[0029] Optionally, the substrate surface is further provided with an environmentally friendly trivalent chromium electroplating layer, and the ultraviolet-curable ink is applied to the surface of the environmentally friendly trivalent chromium electroplating layer by screen printing or pad printing.

[0030] Optionally, the step of applying the UV-curable ink to the surface of the environmentally friendly trivalent chromium electroplated layer using pad printing includes:

[0031] The UV-curable ink is injected into the printing plate of the pad printing machine;

[0032] The pad printing head is pressed down onto the printing plate, with a compression deformation of 40% to 60% and a contact time of 0.3s to 1s, so that the pad printing head adsorbs the UV-curable ink.

[0033] The pad printing head is moved above the environmentally friendly trivalent chromium electroplating layer and contacts the environmentally friendly trivalent chromium electroplating layer with a pressure of 0.3MPa~0.8MPa, so that the UV-curable ink is transferred to the surface of the environmentally friendly trivalent chromium electroplating layer.

[0034] Optionally, in the UV curing step, the UV light wavelength is 395nm and the UV light intensity is 3500mW / cm². 2 ~5000mW / cm 2 The UV curing time is 5s~6s.

[0035] Optionally, before the UV curing step, the process may include drying at 70°C to 80°C for 10 to 15 minutes.

[0036] The raw materials for preparing the high-gloss environmentally friendly trivalent chromium surface UV-curable ink of this application include a certain proportion of polyurethane acrylate resin, epoxy acrylate resin, glycol diacrylate, phosphate acrylate, polyvinyl butyral (PVB), and photoinitiator. The components work synergistically to improve the chemical bonding and physical combination between the ink layer and the environmentally friendly trivalent chromium electroplating product, so that the UV-curable ink has good adhesion and wear resistance on the surface of the environmentally friendly trivalent chromium electroplating product.

[0037] Specifically, the resin system comprises epoxy acrylate resin and polyurethane acrylate resin, resulting in high adhesion and flexibility. Epoxy acrylate resin contains numerous polar groups such as hydroxyl, ester, and ether bonds, which can form hydrogen bonds or chemical bonds with the environmentally friendly trivalent chromium plating layer on the surface of the product, generating dense and strengthened intermolecular forces, thus achieving physical adsorption and providing excellent adhesion. Polyurethane acrylate resin combines flexibility and adhesion, mitigating the shrinkage pressure generated during the curing process of UV-curable inks. Phosphate acrylates and glycol diacrylates form the diluent monomers. The phosphate groups at one end of the phosphate acrylate molecules have a strong affinity for the surface of the environmentally friendly trivalent chromium plating layer, preferentially migrating and adsorbing onto it. The acrylate groups at the other end face inwards towards the ink liquid, participating in the photopolymerization reaction and chemically integrating into the final three-dimensional cross-linked polymer network through covalent bonds, strongly "rivet" the robust inorganic substrate and organic polymer coating together. The addition of glycol diacrylate not only participates in the polymerization reaction but also reduces curing shrinkage stress, preventing adhesion degradation due to stress concentration. PVB's long-chain molecules are physically adsorbed onto the surface of the environmentally friendly trivalent chromium electroplated layer through polar groups such as hydroxyl groups in their molecules. While not participating in chemical cross-linking, they physically entangle and penetrate the forming cross-linking network during curing. The flexible PVB segments dispersed in the system can act as stress concentration points and energy dissipation centers, absorbing and dispersing the volume shrinkage and internal stress generated by photocuring through the movement and deformation of their molecular chains. This reduces the risk of stress directly attacking the interface between the coating and the environmentally friendly trivalent chromium electroplated product, leading to interface damage such as cracking or peeling.

[0038] Therefore, this application proposes and implements a UV-curable ink suitable for trivalent chromium plating surfaces, aiming to solve the problem of strong adhesion of UV-curable inks to low surface energy trivalent chromium plating. Through a unique resin system design and the compounding of multiple components, this application enables the ink to achieve good wetting and initial anchoring of the environmentally friendly trivalent chromium substrate before UV irradiation, forming a strong chemical and physical bond upon UV curing, offering advantages such as environmental friendliness, energy saving, and rapid adhesion. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a scanning electron microscope image of the article prepared in Example 5 of this application;

[0041] Figure 2This is a scanning electron microscope image of the article prepared in Comparative Example 1 of this application. Detailed Implementation

[0042] To facilitate understanding of this application, a more comprehensive description of the application will be provided below in conjunction with specific embodiments. Preferred embodiments of the application are given in the specific embodiments. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0044] Unless otherwise stated or in case of conflict, the terms or phrases used in this application shall have the following meanings:

[0045] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include at least one of those features.

[0046] In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

[0047] In this application, "one or more" refers to any one, two, or more of the listed items. "Multiple" refers to any two or more of the listed items.

[0048] In this application, terms such as "further," "even more," "particularly," "for example," "like," "example," and "exemplary" are used for descriptive purposes to indicate a connection in the coverage of different technical solutions presented earlier and later, but should not be construed as limiting the preceding technical solution or restricting the scope of protection herein. Unless otherwise specified herein, A (e.g., B) indicates that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0049] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "present" or "absent." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. In this application, descriptions such as "optionally contains" and "optionally includes" indicate "contains or does not contain." "Optional component X" indicates whether component X exists or does not exist, or whether component X is contained or not.

[0050] When a numerical range is disclosed in this application, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed in this application should be understood to include any and all subranges to which they are included.

[0051] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0052] The terms "comprising" and "having," and any variations thereof, used in the embodiments of this application, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to such processes, methods, products, or devices.

[0053] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0054] The applicant's research found that traditional UV-curable inks have difficulty forming good adhesion and exhibit poor abrasion resistance on the surface of environmentally friendly trivalent chromium electroplated products, mainly due to the following reasons:

[0055] (1) Surface energy contradiction and wetting failure: The surface energy of environmentally friendly trivalent chromium electroplating layer is usually high (>40mN / m), but the actual adhesion is low. This is because there is a microscopic inert contamination layer on its surface (formed by release agent residue, oxide film or organic pollutants, etc.), forming a "weak boundary layer". UV-cured inks need to be fully spread to form molecular-level contact, but contaminants cause a sharp drop in local surface energy (which can be lower than 30mN / m), hindering ink wetting.

[0056] (2) Chemical inertness hinders bonding: The surface of environmentally friendly trivalent chromium electroplated metal lacks active functional groups (such as -OH, -COOH), and the dense and non-porous structure of the environmentally friendly trivalent chromium electroplated layer further blocks the possibility of physical anchoring.

[0057] (3) Curing shrinkage stress peeling interface: When UV curing ink is cured, it cross-links instantly, and the volume shrinkage rate reaches 10%~15%, which generates high shear stress on the surface of rigid environmentally friendly trivalent chromium electroplating layer. However, the environmentally friendly trivalent chromium electroplating layer has a high elastic modulus (e.g., about 200 GPa) and cannot absorb stress through deformation, resulting in microcracks and peeling at the interface.

[0058] (4) Mismatch in coefficients of thermal expansion: The coefficient of thermal expansion of the environmentally friendly trivalent chromium electroplated metal is approximately 12 × 10⁻⁶. -6 / ℃~18×10 -6 The temperature (°C) is much lower than that of UV-cured ink curing films (CTE≈60×10). -6 / ℃~100×10 -6 The coefficient of thermal expansion (°C). When the temperature fluctuates, the interface generates internal stress due to the difference in expansion and contraction, accelerating delamination.

[0059] Based on this, the first aspect of this application provides a high-gloss, environmentally friendly trivalent chromium surface UV-curable ink. The raw materials for preparing the UV-curable ink, by weight, include: 35 to 45 parts of polyurethane acrylate resin, 15 to 30 parts of epoxy acrylate resin, 10 to 20 parts of glycol diacrylate, 5 to 10 parts of phosphate acrylate, 3 to 8 parts of polyvinyl butyral, and 3 to 5 parts of photoinitiator.

[0060] The high-gloss environmentally friendly trivalent chromium surface UV-curable ink of this application improves the chemical bonding and physical combination between the ink and the environmentally friendly trivalent chromium electroplating product by improving the selection and ratio of resin, monomer, photoinitiator and additives, so that the UV-curable ink has good adhesion and wear resistance on the surface of the environmentally friendly trivalent chromium electroplating product.

[0061] Specifically, a resin system with high adhesion and flexibility is composed of epoxy acrylate resin and polyurethane acrylate resin. Epoxy acrylate resin contains numerous polar groups such as hydroxyl groups, ester groups, and ether bonds, which can form hydrogen bonds or chemical bonds with the surface of the environmentally friendly trivalent chromium electroplated layer, generating dense and strengthened intermolecular forces, thereby achieving physical adsorption and providing excellent adhesion. Polyurethane acrylate resin combines flexibility and adhesion, mitigating the shrinkage pressure generated during the curing process of UV-curable inks. Phosphate acrylates and glycol diacrylates serve as diluent monomers. The phosphate groups at one end of the phosphate acrylate molecules have a strong affinity for the surface of the environmentally friendly trivalent chromium electroplated layer, preferentially migrating and adsorbing onto it. The acrylate groups at the other end face into the ink liquid, participating in the photopolymerization reaction and chemically integrating into the final three-dimensional cross-linked polymer network through covalent bonds, strongly "rivet" the robust inorganic substrate and organic polymer coating together. The addition of glycol diacrylate not only participates in the polymerization reaction but also reduces curing shrinkage stress, preventing adhesion degradation due to stress concentration. PVB's long-chain molecules are physically adsorbed onto the metal surface through polar groups such as hydroxyl groups. While not participating in chemical cross-linking, they physically entangle and penetrate the forming cross-linking network during curing. The flexible PVB segments dispersed in the system can act as stress concentration points and energy dissipation centers, absorbing and dispersing the volume shrinkage and internal stress generated by photocuring through the movement and deformation of their molecular chains. This reduces the risk of stress directly attacking the coating-substrate interface, leading to interface damage such as cracking or peeling.

[0062] Therefore, in the above-mentioned high-gloss environmentally friendly trivalent chromium surface UV-curable ink, the components work synergistically to improve its adhesion and wear resistance on the surface of environmentally friendly trivalent chromium electroplated products.

[0063] In this application, high gloss refers to a gloss level ≥ 500 GU measured at a 60° angle. Environmentally friendly refers to the advantages of trivalent chromium compared to hexavalent chromium, such as its environmental friendliness.

[0064] In some embodiments, the mass fraction of polyurethane acrylate resin in the raw materials for preparing UV-curable ink may be, but is not limited to, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, or any combination of these values.

[0065] In some embodiments, the mass fraction of epoxy acrylate resin in the raw materials for preparing UV-curable ink may be, but is not limited to, 15 parts, 16 parts, 17 parts, 18 parts, 20 parts, 21 parts, 22 parts, 23 parts, 25 parts, 26 parts, 28 parts, 30 parts, or any combination of these values.

[0066] Diol diacrylates refer to acrylate compounds formed from diols and acrylic acid. Specifically, the diol has five or more carbon atoms. In some embodiments, diol diacrylates include one or more of hexanediol diacrylate, neopentyl glycol diacrylate, and polyethylene glycol diacrylate.

[0067] In some embodiments, the mass fraction of glycol diacrylate in the raw materials for preparing UV-curable ink may be, but is not limited to, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, or any combination of these values.

[0068] Phosphate acrylates refer to organic compounds that contain both acrylate groups and phosphate groups. Specifically, phosphate acrylates include one or more of methacryloyloxyethyl phosphate and 2-hydroxyethyl methacrylate phosphate.

[0069] In some embodiments, the mass fraction of phosphate acrylate in the raw materials for preparing UV-curable inks may be, but is not limited to, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, or any combination of these values.

[0070] In some embodiments, the photoinitiator includes one or more of TPO (2,4,6-trimethylbenzoyl-diphenylphosphine oxide), TPO-L (ethyl 2,4,6-trimethylbenzoylphenylphosphonate), ITX (2-isopropylthioxanthone), and TMO (2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide). Using the above photoinitiators enables deep curing and avoids insufficient curing of the underlying layer due to the reflectivity of the environmentally friendly trivalent chromium electroplated surface.

[0071] In some embodiments, the mass fraction of photoinitiator in the raw materials for preparing UV-curable inks may be, but is not limited to, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, or any combination of these values.

[0072] In some embodiments, the mass fraction of polyvinyl butyral (PVB) in the raw materials for preparing UV-curable inks may be, but is not limited to, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, or any combination of these values.

[0073] In some embodiments, the raw materials for preparing UV-curable inks, by weight, include: 40 to 45 parts of polyurethane acrylate resin, 15 to 20 parts of epoxy acrylate resin, 10 to 20 parts of glycol diacrylate, 5 to 10 parts of phosphate acrylate, 5 to 8 parts of polyvinyl butyral, and 4 to 5 parts of photoinitiator.

[0074] In some embodiments, the raw materials for preparing UV-curable inks further include, by weight, 1 to 2 parts of silane coupling agent. Specifically, the silane coupling agent includes, but is not limited to, KH-560. Adding a silane coupling agent to the UV-curable ink allows the silane coupling agent to hydrolyze and generate silanol groups (-Si-OH), which react with the hydroxyl groups on the surface of the environmentally friendly trivalent chromium electroplated layer to form Si-OM covalent bonds. This further improves adhesion and creates a strong, durable bond.

[0075] In some embodiments, the raw materials for preparing UV-curable inks, by weight, further include: 0.2 to 0.5 parts of wetting agent and / or 3 to 10 parts of color ink.

[0076] Adding wetting agents to UV-curable inks can further improve the ink's spreadability on the surface of environmentally friendly trivalent chromium electroplated layers, reducing interface defects. It can also reduce surface tension, making it easier for the ink to penetrate into the micropores of the environmentally friendly trivalent chromium electroplated layer. Adding colorants to UV-curable inks allows for color adjustment to meet the needs of different applications.

[0077] Specifically, the wetting agent includes BYK-333. Color inks can be selected based on the color of the UV-curable ink; details will not be elaborated here.

[0078] In some embodiments, the method for preparing UV-curable ink includes the following steps: mixing the components according to the formulation ratio and grinding to a fineness ≤5μm. Further, mixing the components according to the formulation ratio and grinding to a fineness ≤2μm. Specifically, placing the components in a grinding mixer and mixing thoroughly at 1000r / min. Specifically, the grinding step is carried out in a three-roll mill.

[0079] A second aspect of this application provides an article comprising a substrate and an ink layer disposed on the surface of the substrate, the ink layer being obtained by curing with the aforementioned ultraviolet-curable ink.

[0080] In some embodiments, the thickness of the ink layer is 10 μm to 20 μm.

[0081] In some embodiments, the article further includes an environmentally friendly trivalent chromium electroplating layer disposed between the substrate and the ink layer. Currently, the surface of environmentally friendly trivalent chromium electroplated products mainly uses thermosetting resins that undergo prolonged high-temperature thermosetting to form the ink layer, which consumes a lot of energy. In some embodiments of this application, ultraviolet light curing ink is used to obtain the ink layer, which helps to reduce energy consumption.

[0082] Furthermore, the environmentally friendly trivalent chromium electroplating layer is a bright environmentally friendly trivalent chromium electroplating layer. Specifically, the gloss of the environmentally friendly trivalent chromium electroplating layer, measured at a 60° angle, is ≥500 GU. The roughness Ra of the environmentally friendly trivalent chromium electroplating layer is ≤0.1 μm, and the roughness Rz is ≤0.05 μm.

[0083] In some embodiments, the article includes hardware articles or bathroom articles.

[0084] A third aspect of this application provides a method for preparing an article, comprising the following steps:

[0085] UV-curable ink is applied to the surface of a substrate and then cured using UV light to obtain the product.

[0086] Among them, the UV-curable ink is the UV-curable ink of the first aspect mentioned above.

[0087] In some embodiments, the substrate surface is further provided with an environmentally friendly trivalent chromium electroplating layer, and ultraviolet-cured ink is applied to the surface of the environmentally friendly trivalent chromium electroplating layer by screen printing or pad printing.

[0088] Specifically, the steps of applying UV-curable ink to the surface of an environmentally friendly trivalent chromium electroplated layer using pad printing include:

[0089] Inject UV-curable ink into the printing plate of the pad printing machine;

[0090] Press the pad printing head down onto the printing plate, compressing it by 40% to 60% for a contact time of 0.3 to 1 second, so that the pad printing head can absorb UV-cured ink.

[0091] Move the pad printing head above the environmentally friendly trivalent chromium electroplating layer and apply a pressure of 0.3MPa~0.8MPa to contact the environmentally friendly trivalent chromium electroplating layer, so that the UV-curable ink is transferred to the surface of the environmentally friendly trivalent chromium electroplating layer.

[0092] Compared to screen printing inks, pad printing inks form a thinner ink layer, causing the environmentally friendly trivalent chromium electroplated layer to cure before it is fully wetted or penetrated, resulting in insufficient adhesion. Therefore, traditional UV-curable inks exhibit poor adhesion when applied to the surface of environmentally friendly trivalent chromium electroplated layers and can only be used with screen printing. However, the UV-curable inks of some embodiments of this application can form an ink layer not only by screen printing but also by pad printing, and the ink layer exhibits excellent adhesion to the environmentally friendly trivalent chromium electroplated layer.

[0093] Specifically, after the step of injecting UV-curable ink into the printing plate of the pad printing machine, the process further includes: performing ten back-and-forth blank passes to ensure that the UV-curable ink evenly covers the surface of the printing plate. In one example, the printing plate is a steel plate.

[0094] Specifically, compression deformation is the percentage of the shortening distance in the axial direction (vertical direction) of the pad printing head when it contacts the printing plate under a certain pressure, relative to the original height of the pad printing head. That is: compression deformation = (original height of pad printing head - height after compression) / original height × 100%.

[0095] Specifically, in the step of pressing the pad printing head down onto the printing plate, the pressing speed is 10m / s.

[0096] Specifically, in the UV curing step, the UV light wavelength is 395nm and the UV light intensity is 3500mW / cm². 2 ~5000mW / cm 2 The UV curing time is 5s~6s.

[0097] In some embodiments, prior to the UV curing step, the process further includes drying at 70°C to 80°C for 10 to 15 minutes. This treatment helps reduce viscosity, improve wettability, and promote intermolecular interactions.

[0098] To make the objectives and advantages of this application clearer, the following detailed description, in conjunction with specific embodiments, illustrates the high-gloss, environmentally friendly trivalent chromium surface UV-curable ink and its effects. It should be understood that the specific embodiments described herein are merely illustrative and should not be construed as limiting the scope of this application. Unless otherwise specified, the following embodiments do not include components other than unavoidable impurities. Unless otherwise specified, the pharmaceuticals and instruments used in the embodiments are conventionally chosen in the art. Experimental methods not specifying specific conditions in the embodiments were implemented under conventional conditions, such as those described in literature, books, or methods recommended by the manufacturer.

[0099] The raw materials used in the following examples and comparative examples are as follows:

[0100] Epoxy acrylate resin (model: B-100) and polyurethane acrylate resin (model: B-251) were purchased from Shanghai Yangshi Industrial Co., Ltd.; methacryloyloxyethyl phosphate (CAS No.: 24599-21-1), HDDA (hexanediol diacrylate CAS No.: 13048-33-4), KH-560 (CAS No.: 2530-83-8), TPO (CAS No.: 75980-60-8) and polyvinyl butyral (CAS No.: 63148-65-2) were purchased from Maclean's Reagent Network; BYK-333 was purchased from BYK Chemical (Germany); and color inks were selected according to the color requirements of the inks and purchased from Guangzhou Moke Chemical Co., Ltd.

[0101] Sartoma aliphatic polyurethane resin was purchased from Sartoma Corporation, USA, CN965; acrylic reactive monomers PONPGDA (propoxylated neopentyl glycol diacrylate, CAS No.: 84170-74-1), 12EOTMPTA (ethoxylated trimethylolpropane ester, CAS No.: 28961-43-5), photoinitiator 907 [2-methyl-1-(4-methylthiophenyl)-2-morphoacetone, CAS No.: 71868-10-5] and photoinitiator DETX [2,4-diethylthioxanthone, CAS No.: 82799-44-8] were purchased from Maclean's Reagent Network; BASF Cromophytal series pigments were selected.

[0102] Example 1

[0103] This embodiment provides a UV-curable ink. The raw materials for preparing the UV-curable ink, by weight, include: 35 parts of polyurethane acrylate resin, 30 parts of epoxy acrylate resin, 10 parts of HDDA (hexanediol diacrylate), 5 parts of methacryloyloxyethyl phosphate, 1 part of silane coupling agent KH-560, 3 parts of photoinitiator TPO, 0.2 parts of wetting agent BYK-333, 3 parts of polyvinyl butyral, and 5 parts of color ink.

[0104] Examples 2 to 5

[0105] Examples 2 to 5 each provide a UV-curable ink, the specific composition and formulation of which are shown in Table 1 below.

[0106] Table 1. Composition and proportions of UV-curable inks in each embodiment.

[0107]

[0108] Example 6

[0109] This embodiment provides a UV-curable ink, similar to the UV-curable ink of Example 1, except that it does not contain a silane coupling agent. Everything else is the same as in Example 1.

[0110] Example 7

[0111] This embodiment provides a UV-curable ink, which is similar to the UV-curable ink of Example 1, except that neopentyl glycol diacrylate is used instead of hexanediol diacrylate in Example 1, and 2-hydroxyethyl methacrylate phosphate is used instead of methacryloyloxyethyl phosphate in Example 1.

[0112] Comparative Example 1

[0113] Comparative Example 1 provides a UV screen printing ink, which is prepared by the following steps:

[0114] Mix 560g of Sartoma aliphatic polyurethane, 270g of acrylic active monomers (135g each of propoxylated neopentyl glycol diacrylate and ethoxylated trimethylolpropane triacrylate), 90g of photoinitiator (72g of photoinitiator 907 and 18g of photoinitiator DETX), 65g of pigment, 7g of Dow Corning surface leveling agent DC-27, and 8g of Dow Corning defoamer DC-163. Use a thermostatic magnetic stirrer, keep the machine at 50℃, and stir at 800~1000rpm for 30~60min to disperse evenly. Grind the mixture on a three-roll mill until the fineness is ≤2μm.

[0115] Comparative Examples 2 to 6

[0116] Comparative Examples 2 to 6 each provide a UV-curable ink, similar to the UV-curable ink of Example 1, except that the proportions of each component in the UV-curable ink are different. Details are shown in Table 2 below.

[0117] Table 2

[0118]

[0119] The UV-curable inks of the above embodiments and comparative examples were transferred and cured on a substrate containing a high-gloss environmentally friendly trivalent chromium electroplated layer. The specific steps are as follows:

[0120] (1) Ink filling: Inject UV-curable ink into the ink trough of the pad printing machine steel plate, and make ten back-and-forth empty runs to make the ink evenly cover the surface of the steel plate.

[0121] (2) Ink transfer: The pad printing head is pressed down onto the steel plate at a vertical speed of 10 m / s, with a compression deformation of 50% and a contact time of 0.5 s, so that the pad printing head absorbs the UV-curable ink in the ink tank. The pad printing head is moved above the chromium-plated substrate and pressed with a constant pressure of 0.5 MPa to transfer the UV-curable ink to the surface of the substrate containing the environmentally friendly trivalent chromium electroplating layer.

[0122] (3) Curing: First, place the substrate containing the environmentally friendly trivalent chromium electroplating layer in a 70℃ oven and bake for 10 minutes. Then, perform photocuring by irradiating the transferred pattern with an LED-UV light source. The light source wavelength is 395nm and the intensity is 3500mW / cm. 2 The curing time is 5-6 seconds, and the total energy reaches 15000 mJ / cm². 2 .

[0123] The products obtained by pad printing and curing the inks obtained in the above embodiments and comparative examples on a substrate containing an environmentally friendly trivalent chromium electroplating layer were subjected to relevant performance tests. The test methods are as follows:

[0124] (1) Cross-cut adhesion test: The test shall be conducted at three different locations in accordance with the provisions of standard GB / T 9286 "Cross-cut adhesion test for paints and varnishes". The results of the cross-cut adhesion test shall be not lower than level 1, which shall be considered as qualified.

[0125] (2) Alcohol abrasion resistance test: Under the conditions of (23±2)℃ and (50±5)% relative humidity, a 1.5kg metal weight was wrapped with white non-woven cloth soaked in anhydrous alcohol. The circular base was placed on the surface of the painted part and pushed back and forth at a uniform speed. Each push was about 20cm long and about 2 seconds per push. One push and one push was counted as one push. The results were recorded every 10 pushes.

[0126] (3) Chemical resistance test: The test shall be conducted according to the drop method specified in GB / T9274. Three drops of test liquid, each with a volume of about 0.1 mL, shall be dropped onto a flat coating surface and kept for 16 hours. After rinsing with water and drying with a soft cloth, the coating surface shall be inspected with a 4x magnifying glass. The surface shall be free of pits, bubbles, wrinkles, cracks, peeling, corrosion or exposure of the substrate. Slight color changes and loss of gloss are allowed. The test liquids include: 2N (equivalent concentration) sodium hydroxide aqueous solution, 2N ammonia water, 10% acetic acid aqueous solution, 10% hydrogen peroxide, anhydrous ethanol, and 10 g / L polyoxyethylene ether aqueous solution.

[0127] (4) Thermal shock test: The sample is subjected to 4 cycles of testing, one of which is as follows: the sample is placed in an environment of (-40±2)℃ for 1 hour; then the sample is placed in an environment of (20±5)℃ for 1 hour; then the sample is placed in an environment of (75±2)℃ for 1 hour; and finally the sample is placed in an environment of (20±5)℃ for 1 hour. If there are no adverse phenomena such as blistering, discoloration, peeling, or corrosion on the surface after 4 cycles of testing, it is considered qualified.

[0128] (5) Salt spray test: According to the standard GB / T10125-2021 "Artificial atmosphere corrosion test salt spray test", the level is not lower than 10 after 48 hours of testing, which is considered qualified.

[0129] The test results are shown in Tables 3 and 4 below.

[0130] Table 3

[0131]

[0132] Table 4

[0133]

[0134] As can be seen from the table above, the UV-curable ink used in the application embodiment, compared with the comparative example, can form an ink layer with good adhesion and wear resistance on the surface of a substrate containing an environmentally friendly trivalent chromium electroplated layer through a pad printing process, while also having excellent resistance to chemical reagents, high and low temperatures, and corrosion.

[0135] In Comparative Example 1, traditional UV screen printing ink was used to form an ink layer on the surface of a substrate containing an environmentally friendly trivalent chromium electroplated layer using screen printing. In the alcohol abrasion resistance test, the ink peeled off after 30 cycles, indicating poor abrasion resistance. Furthermore, in tests with 2N sodium hydroxide, 2N ammonia, and 10% hydrogen peroxide, the ink corroded and peeled off, demonstrating poor chemical resistance. In Comparative Examples 2-6, the UV-curable inks used components outside the scope of the embodiments in this application, and an ink layer was formed on the surface of a substrate containing an environmentally friendly trivalent chromium electroplated layer using pad printing. The ink layers exhibited poor abrasion resistance and poor chemical resistance.

[0136] Figure 1 This is a scanning electron microscope image of the article prepared in Example 5 of this application. Figure 2 This is a scanning electron microscope (SEM) image of the product prepared in Comparative Example 1. From... Figure 1 and Figure 2 As can be seen, in the product prepared in Example 5, the adhesion between the ink layer and the environmentally friendly trivalent chromium electroplating layer of the substrate is good and there are no obvious gaps, while in the product prepared in Comparative Example 1, there are large gaps between the ink layer and the environmentally friendly trivalent chromium electroplating layer of the substrate.

[0137] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0138] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A high-gloss, environmentally friendly trivalent chromium surface UV-curable ink, characterized in that, The raw materials for preparing the UV-curable ink, by weight, include: 35-45 parts of polyurethane acrylate resin, 15-30 parts of epoxy acrylate resin, 10-20 parts of glycol diacrylate, 5-10 parts of phosphate acrylate, 3-8 parts of polyvinyl butyral, and 3-5 parts of photoinitiator.

2. The high-gloss, environmentally friendly trivalent chromium surface UV-curable ink according to claim 1, characterized in that, The diol diacrylate includes one or more of hexanediol diacrylate, neopentyl glycol diacrylate, and polyethylene glycol diacrylate; and / or, The phosphate acrylates include one or more of methacryloyloxyethyl phosphate and 2-hydroxyethyl methacrylate phosphate; and / or, The photoinitiator includes one or more of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 2-isopropylthioxanthone, and 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide.

3. The high-gloss, environmentally friendly trivalent chromium surface UV-curable ink according to claim 1, characterized in that, The raw materials for preparing the UV-curable ink, by weight, include: 40-45 parts polyurethane acrylate resin, 15-20 parts epoxy acrylate resin, 10-20 parts glycol diacrylate, 5-10 parts phosphate acrylate, 5-8 parts polyvinyl butyral, and 4-5 parts photoinitiator; or, The raw materials for preparing the UV-curable ink, by weight, include: 35 parts polyurethane acrylate resin, 30 parts epoxy acrylate resin, 5 parts methacryloyloxyethyl phosphate, 10 parts hexanediol diacrylate, 3 parts polyvinyl butyral, and 3 parts photoinitiator; or, The raw materials for preparing the UV-curable ink, by weight, include: 35 parts polyurethane acrylate resin, 30 parts epoxy acrylate resin, 10 parts methacryloyloxyethyl phosphate, 20 parts hexanediol diacrylate, 3 parts polyvinyl butyral, and 3 parts photoinitiator; or, The raw materials for preparing the UV-curable ink, by weight, include: 40 parts polyurethane acrylate resin, 20 parts epoxy acrylate resin, 8 parts methacryloyloxyethyl phosphate, 15 parts hexanediol diacrylate, 5 parts polyvinyl butyral, and 4 parts photoinitiator; or, The raw materials for preparing the UV-curable ink, by weight, include: 45 parts polyurethane acrylate resin, 15 parts epoxy acrylate resin, 5 parts methacryloyloxyethyl phosphate, 10 parts hexanediol diacrylate, 8 parts polyvinyl butyral, and 5 parts photoinitiator; or, The raw materials for preparing the UV-curable ink, by weight, include: 45 parts of polyurethane acrylate resin, 15 parts of epoxy acrylate resin, 10 parts of methacryloyloxyethyl phosphate, 20 parts of hexanediol diacrylate, 8 parts of polyvinyl butyral, and 5 parts of photoinitiator.

4. The high-gloss, environmentally friendly trivalent chromium surface UV-curable ink according to any one of claims 1 to 3, characterized in that, The raw materials for preparing the UV-curable ink, by weight, further include: 1 to 2 parts of silane coupling agent, optionally, the silane coupling agent includes KH-560; and / or, The raw materials for preparing the UV-curable ink, by weight, also include: 0.2 to 0.5 parts of wetting agent and 3 to 10 parts of color ink. Optionally, the wetting agent includes BYK-333.

5. An article, characterized in that, include: The substrate and the ink layer disposed on the surface of the substrate are obtained by curing the ink layer with the high-gloss environmentally friendly trivalent chromium surface UV-curable ink as described in any one of claims 1 to 4; Optionally, the article further includes an environmentally friendly trivalent chromium electroplating layer disposed between the substrate and the ink layer.

6. The article of claim 5, characterized in that, The thickness of the ink layer is 10μm~20μm; and / or, The environmentally friendly trivalent chromium electroplated layer has a gloss level of ≥500 GU when measured at a 60° angle; and / or, The environmentally friendly trivalent chromium electroplating layer has a roughness Ra ≤ 0.1 μm and a roughness Rz ≤ 0.05 μm; and / or, The products include hardware products or bathroom products.

7. A method for preparing an article, characterized in that, Includes the following steps: UV-curable ink is applied to the surface of a substrate and then cured using UV light to obtain the product. The UV-curable ink is the high-gloss environmentally friendly trivalent chromium surface UV-curable ink as described in any one of claims 1 to 4.

8. The method for preparing the article according to claim 7, characterized in that, The substrate surface is also provided with an environmentally friendly trivalent chromium electroplating layer, and the ultraviolet curable ink is applied to the surface of the environmentally friendly trivalent chromium electroplating layer by screen printing or pad printing.

9. The method for preparing the article according to claim 8, characterized in that, The step of applying the UV-curable ink to the surface of the environmentally friendly trivalent chromium electroplated layer using pad printing includes: The UV-curable ink is injected into the printing plate of the pad printing machine; The pad printing head is pressed down onto the printing plate, with a compression deformation of 40% to 60% and a contact time of 0.3s to 1s, so that the pad printing head adsorbs the UV-curable ink. The pad printing head is moved above the environmentally friendly trivalent chromium electroplating layer and contacts the environmentally friendly trivalent chromium electroplating layer with a pressure of 0.3MPa~0.8MPa, so that the ultraviolet curable ink is transferred to the surface of the environmentally friendly trivalent chromium electroplating layer.

10. The method for preparing the article according to any one of claims 7 to 9, characterized in that, In the UV curing step, the UV light wavelength is 395nm and the UV light intensity is 3500mW / cm². 2 ~5000mW / cm 2 The UV curing time is 5s~6s; And / or, Before the UV curing step, the process also includes drying at 70℃~80℃ for 10min~15min.

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