Ink, method for preparing the same and use thereof

Abstract

The application discloses an ink and a preparation method and application thereof, and belongs to the technical field of ink. The ink provided by the application comprises a main agent, a silane coupling agent and a curing agent. The main agent comprises a polycarbonate resin and an aldehyde ketone resin. The hydroxyl value of the aldehyde ketone resin is 30-150 mgKOH / g. The mass ratio of the polycarbonate resin to the aldehyde ketone resin is 5-20:55-70. When the ink provided by the application is applied to a metal plating layer surface, the ink has high leveling effect, and the adhesion between the obtained ink coating and the metal plating layer is excellent. The application further provides a preparation method and application of the ink.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ink, in particular to an ink and a preparation method and application thereof. BACKGROUND

[0002] With the upgrading of mobile phones, the selection of mobile phone battery cover materials is also gradually diversified, among which epoxy + glass fiber, epoxy + carbon fiber plates are mainly used. In order to obtain a unique appearance effect, a coating layer is arranged on the surface of the plate; for example, in order to realize the metal texture and gloss of the plate, instead of the appearance effect of metal material, a layer of metal atoms is generally covered on the plate through physical vapor deposition process, and then an ink coating layer is arranged on the surface of the metal plating layer to further enrich the appearance effect and protect the metal plating layer.

[0003] However, with the iteration of the process, the types of metal and the plating process are becoming more and more complex, which leads to problems in the appearance leveling and performance of the ink coating on its surface. In order to solve the above problems, the traditional scheme generally improves the wetting problem on the plating layer by adding a silicon fluoride leveling agent, but the leveling wetting agent, while improving the appearance performance of the ink, its characteristics of forming a weak boundary layer by enriching the interface, will physically block and weaken the key adhesion between the ink resin and the metal plating layer, resulting in performance degradation.

[0004] In summary, the traditional ink is difficult to simultaneously improve the leveling performance and adhesion performance on the surface of the metal plating layer. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides an ink, which has high leveling effect when applied to the surface of a metal plating layer, and the adhesion between the obtained ink coating layer and the metal plating layer is excellent.

[0006] The present application also provides a preparation method of the above-mentioned ink.

[0007] The present application also provides an application of the above-mentioned ink.

[0008] According to the embodiment of the first aspect of the present application, an ink is provided, the ink comprising a main agent, a silane coupling agent and a curing agent;

[0009] The main agent comprises a polycarbonate resin and an aldehyde ketone resin;

[0010] The aldehyde ketone resin has a hydroxyl value of 30-150 mgKOH / g;

[0011] The mass ratio of the polycarbonate resin to the aldehyde ketone resin is 5-20:55-70.

[0012] The ink according to the embodiment of the present application has at least the following beneficial effects:

[0013] This invention, by selecting aldehyde-ketone resin as the main resin and combining it with a curing agent and a silane coupling agent, produces an ink that provides excellent appearance and performance on the surface of metal plating; specifically,

[0014] The rigid structure of aldehyde-ketone resins gives them extremely high mobility in liquid systems, allowing them to rapidly diffuse to the interface between the coating and the metal plating. Their densely packed ketone carbonyl groups (C=O) and hydroxyl groups (-OH) can immediately form strong hydrogen bonds and dipole-dipole interactions with the oxides or hydrated layers on the metal plating surface. However, the more hydroxyl groups there are, the more difficult it becomes to wet low-surface-energy substrates, and the more they participate in the cross-linking reaction of the curing agent, leading to a rapid increase in the viscosity of the ink system and a shortened "pot life," which may actually limit the leveling effect. Due to the rigidity of the aldehyde-ketone resin molecular chains, if used alone, the resulting film may break directly due to brittleness. Polycarbonate diol resins, with their combination of rigidity and flexibility, can improve the flexibility and water resistance of the ink coating to a certain extent, preventing paint chipping and hydrolysis that reduce adhesion; however, if used alone, polycarbonate resins will affect the leveling effect of the ink. This invention uses a mixture of the two resins. During the preparation and storage of the ink, the molecular chains of the polycarbonate diol extend and mix thoroughly with the aldehyde-ketone resin. When the ink cures into a film, the rigid chains of the aldehyde-ketone resin can interpenetrate and wrap around the molecular chains of the polycarbonate resin like "wooden stakes," forming a three-dimensional network with a physically interpenetrating network structure. This three-dimensional interpenetrating network structure can significantly improve the adhesion, temperature resistance, water resistance, and mechanical strength of the film obtained from the ink. This invention also limits the ratio of polycarbonate resin to aldehyde-ketone resin. If the proportion of polycarbonate is too high, it may cause entanglement during ink flow, reducing fluidity and ultimately affecting the leveling performance of the ink. If the proportion of aldehyde-ketone resin is too high, the rigidity of the cured film obtained from the ink will be too high, making it prone to brittleness.

[0015] The silane coupling agent used in this invention undergoes a condensation reaction with the metal hydroxyl groups (metal oxide hydration) on the surface of the metal coating, removing one molecule of water and forming a strong Si-OM covalent bond, thereby improving the adhesion between the coating formed by the ink and the metal coating.

[0016] In summary, this invention selects aldehyde-ketone resins with suitable hydroxyl values, combines them with polycarbonate resins, curing agents, and silane coupling agents. The synergistic effect of these features allows the resulting ink to form a coating with high adhesion, high leveling, and temperature and humidity resistance on the surface of metal plating.

[0017] According to some embodiments of the present application, the mass ratio of the polycarbonate resin and the aldehyde ketone resin is 5-20:55-70. For example, it can be specifically 1:6, 1:6.5, 1:7, 1:8, 1:9, 1:9.5, 1:10; or a range value formed by any two point values in the above.

[0018] According to some embodiments of the present application, the polycarbonate resin comprises a polycarbonate diol resin.

[0019] According to some embodiments of the present application, the number average molecular weight of the polycarbonate resin is 500-3000. For example, it can be specifically 800, 1000, 1200, 1500, 2000, 2500, 3000; or a range value formed by any two point values in the above. Within the above range, the three-dimensional interpenetrating network structure formed between the molecular chain of the polycarbonate resin and the aldehyde ketone resin is more firm, further improving the leveling property, adhesion, temperature resistance, water resistance and mechanical strength of the ink.

[0020] According to some embodiments of the present application, the hydroxyl value of the polycarbonate resin is 30-300 mgKOH / g. For example, it can be specifically 30 mgKOH / g, 50 mgKOH / g, 80 mgKOH / g, 100 mgKOH / g, 120 mgKOH / g, 150 mgKOH / g, 200 mgKOH / g, 250 mgKOH / g, 300 mgKOH / g; or a range value formed by any two point values in the above.

[0021] According to some embodiments of the present application, the hydroxyl value of the aldehyde ketone resin is 35-145 mgKOH / g. For example, it can be specifically 35 mgKOH / g, 40 mgKOH / g, 50 mgKOH / g, 60 mgKOH / g, 70 mgKOH / g, 80 mgKOH / g, 90 mgKOH / g, 100 mgKOH / g, 110 mgKOH / g, 120 mgKOH / g, 130 mgKOH / g, 140 mgKOH / g, 145 mgKOH / g; or a range value formed by any two point values in the above.

[0022] According to some embodiments of the present application, the component of the main agent further comprises a leveling agent, a defoaming agent and a first solvent.

[0023] According to some embodiments of the present application, the leveling agent comprises an acrylic leveling agent.

[0024] According to some embodiments of the present application, the defoaming agent comprises a non-silicon defoaming agent. For example, it can be specifically a polyolefin defoaming agent.

[0025] According to some embodiments of the present application, the first solvent includes at least one of isophorone, DBE (a mixture of dimethyl succinate, dimethyl glutarate and dimethyl adipate), ethylene glycol butyl ether acetate, diethylene glycol methyl ethyl ether, dipropylene glycol methyl ether acetate, dipropylene glycol butyl ether and ethylene glycol butyl ether.

[0026] According to some embodiments of the present application, the main agent includes, by weight parts:

[0027] polycarbonate resin 5-20 parts;

[0028] aldehyde ketone resin 55-70 parts;

[0029] leveling agent 0.5-1.5 parts;

[0030] defoaming agent 0.2-1 part;

[0031] first solvent 18-30 parts.

[0032] According to some embodiments of the present application, the leveling agent accounts for 0.5-1% of the mass percentage of the main agent; for example, it can be specifically 0.5%, 0.8%, 1%; or a range value composed of any two of the above point values.

[0033] According to some embodiments of the present application, the defoaming agent accounts for 0.5-1% of the mass percentage of the main agent; for example, it can be specifically 0.5%, 0.7%, 1%; or a range value composed of any two of the above point values.

[0034] According to some embodiments of the present application, the first solvent accounts for 20-25% of the mass percentage of the main agent; for example, it can be specifically 20%, 22%, 23%, 24%, 25%; or a range value composed of any two of the above point values.

[0035] According to some embodiments of the present application, the curing agent includes isocyanate. For example, it can be specifically at least one of aliphatic isocyanate and aromatic isocyanate; further specifically, it can be HDI (hexamethylene diisocyanate).

[0036] According to some embodiments of the present application, the silane coupling agent includes at least one of γ-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane and 3-(1,3-dimethylbutenyl)aminopropyltriethoxysilane.

[0037] According to some embodiments of the present application, the mass ratio of the main agent, the curing agent and the silane coupling agent is 100:5-15:1-5. Among them, the mass ratio between the main agent and the curing agent is 100:5-7; for example, it can be specifically 100:6. The mass ratio between the main agent and the silane coupling agent is 100:2-4; for example, it can be specifically 100:3.

[0038] According to some embodiments of the present application, the components of the ink further include a second solvent. For example, it can be specifically isophorone.

[0039] According to some embodiments of the present application, the mass ratio of the main agent and the second solvent is 100:5-15; for example, it can be specifically 100:5, 100:8, 100:10, 100:12, 100:15; or a range value composed of any two point values in the above.

[0040] According to some embodiments of the present application, the ink includes, by weight parts:

[0041] 100 parts of the main agent;

[0042] 5-15 parts of the curing agent;

[0043] 1-5 parts of the silane coupling agent;

[0044] 5-15 parts of the second solvent.

[0045] According to some embodiments of the present application, the ink is an ink applied to the surface of a metal plating layer.

[0046] According to some embodiments of the second aspect of the present application, a preparation method of the ink of the embodiments of the first aspect of the present application is provided, and the preparation method includes the following steps:

[0047] S1. Mixing the components of the main agent;

[0048] S2. Mixing the product obtained in step S1 and other components of the ink.

[0049] Since the preparation method adopts all the technical solutions of the ink of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments.

[0050] According to some embodiments of the present application, in step S1, the mixing is carried out under stirring. The stirring speed is ≥400 rpm. In this way, good mass transfer can be achieved.

[0051] According to some embodiments of the present application, in step S1, the temperature of the mixing is ≤60℃. In this way, the occurrence of side reactions can be significantly avoided.

[0052] According to some embodiments of the present application, in step S1, the mixing comprises the following sub-steps:

[0053] S1a. mixing the polycarbonate resin, the aldehyde ketone resin and the first solvent;

[0054] S1b. mixing the mixture obtained in step S1a and the leveling agent, the defoaming agent.

[0055] According to some embodiments of the present application, in step S1a, the mixing is performed for 10-15 minutes.

[0056] According to some embodiments of the present application, in step S1b, the mixing is performed for 10-15 minutes.

[0057] Within the above range, on the one hand, the uniformity of the mixing can be ensured, and on the other hand, the waste of time and energy caused by long-time stirring can be avoided; the performance of the obtained ink is not obviously affected within the above range.

[0058] According to some embodiments of the present application, the ink is applied to the surface of a metal plating layer.

[0059] Since the application adopts all the technical solutions of the ink of the above embodiments, at least all the beneficial effects brought by the technical solutions of the above embodiments are achieved.

[0060] According to some embodiments of the present application, the cover plate for a mobile phone comprises a substrate, a metal plating layer and an ink coating layer which are arranged in sequence.

[0061] The preparation raw material of the ink coating layer comprises the ink according to the first aspect of the present application.

[0062] Since the cover plate adopts all the technical solutions of the ink of the above embodiments, at least all the beneficial effects brought by the technical solutions of the above embodiments are achieved.

[0063] According to some embodiments of the present application, the substrate comprises an organic base material and a filler arranged in the organic base material. The organic base material comprises at least one of an epoxy resin and a polycarbonate resin. The filler comprises at least one of a glass fiber and a carbon fiber.

[0064] According to some embodiments of the present application, the thickness of the ink coating layer is 6-9 μm. For example, it can be 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm; or a range value formed by any two of the above point values.

[0065] Other features and advantages of the present application will be set forth in the following description, and in part will be apparent from the description, or can be learned by practice of the application. DETAILED DESCRIPTION

[0066] The concept and technical effects of the present application will be described clearly and completely in combination with the embodiments below, so as to fully understand the purposes, features and effects of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative labor are within the protection scope of the present application.

[0067] Example 1

[0068] This example provides an ink and a preparation method thereof, wherein the composition of the ink is shown in Table 1 according to mass fraction.

[0069] The preparation method of the ink is as follows:

[0070] S1. Disperse the polycarbonate resin, aldehyde ketone resin and first solvent at a speed of 400 rpm or more for 10-15 min, then add the leveling agent and defoaming agent and disperse for 10-15 min (temperature control below 60°C), to obtain a main agent;

[0071] S2. Mix the main agent, curing agent, silane coupling agent and second solvent according to a mass ratio of 100:5:2:10, to obtain the target ink of this example;

[0072] The curing agent is N3300 (HDI) from Covestro; the silane coupling agent is z-6040 (γ-glycidoxypropyltrimethoxysilane) from Dow Corning; and the second solvent is isophorone (CAS: 78-59-1);

[0073] In order to avoid the reaction of each component in the ink, the main agent, curing agent, silane coupling agent and second solvent are usually stored separately, and step S2 is performed before use. After step S2 is completed, the obtained ink needs to be used within 4 h.

[0074] Table 1 Composition of the main agent for ink in the examples and comparative examples

[0075]

[0076] In Table 1, the number average molecular weight of Asahi Kasei T5651 is about 1000, and the hydroxyl value is between 100-120 mgKOH / g.

[0077] The hydroxyl value of De Forest Chemicals A-81 is 40 mgKOH / g, and the hydroxyl value of TEGO® Variplus CA is about 110 mgKOH / g.

[0078] The leveling agent used is an acrylic type leveling agent.

[0079] Example 2-3 each prepared an ink, which is different from Example 1 in that:

[0080] Part of the preparation raw material is different, the detailed differences are shown in Table 1.

[0081] Comparative Example 1

[0082] This example provides an ink and a method for preparing the same, which is different from Example 1 in that:

[0083] The polycarbonate resin and aldehyde ketone resin in Example 1 are replaced with equal mass parts of Guolong 6896-70D polyester resin.

[0084] Comparative Example 2

[0085] This example provides an ink and a method for preparing the same, which is different from Comparative Example 1 in that:

[0086] The type of leveling agent is replaced with BYK 333 (fluorosilicon type).

[0087] Comparative Example 3

[0088] This example provides an ink and a method for preparing the same, which is different from Example 1 in that:

[0089] The polycarbonate resin and aldehyde ketone resin in Example 1 are replaced with equal mass parts of Xinyuan NP-1230D acrylic resin.

[0090] Comparative Example 4

[0091] This example provides an ink and a method for preparing the same, which is different from Example 1 in that:

[0092] The aldehyde ketone resin in Example 1 is replaced with equal mass parts of TEGO® Variplus SK aldehyde ketone resin, which has a hydroxyl value of 325 mgKOH / g.

[0093] Comparative Example 5

[0094] This example provides an ink and a method for preparing the same, which is different from Example 1 in that:

[0095] The polycarbonate resin in Example 1 is replaced with equal mass parts of Guolong 6896-70D polyester resin.

[0096] Comparative Example 6

[0097] This example provides an ink and a method for preparing the same, which is different from Example 1 in that:

[0098] In step S2 and the formulation of the ink, no silane coupling agent is added.

[0099] Comparative Example 7

[0100] This example provides an ink and a preparation method thereof, which is different from Example 1 in particular and in that:

[0101] The mass ratio of the polycarbonate resin and the aldehyde ketone resin is different, and the specific mass ratio is shown in Table 1.

[0102] Test Example

[0103] This example tests the performance of the ink obtained in the examples and comparative examples; specifically, the ink prepared in the examples and comparative examples is printed on a substrate using a 350-mesh polyester screen, with a film thickness of 6-9 µm, and then baked at 80°C for 60 min to obtain an ink coating; the substrate used is a glass fiber plate with a metal plating layer, wherein the size of the substrate is 50×100×0.2-0.3 mm, and the metal plating layer is a silicon oxide layer, a titanium oxide layer, a zirconium oxide layer, and an aluminum oxide layer arranged in layers; the silicon oxide layer is in contact with the ink coating. Four times magnification. And the obtained ink coating is tested by the following method:

[0104] Film thickness testing instrument: Japan Mitutoyo sheet type micrometer No. 293 240 30.

[0105] The methods and results of each test are shown in Table 2.

[0106] Table 2 Performance test standards and results of the ink coating obtained in the examples and comparative examples

[0107]

[0108] Comparative Example and Comparative Example 7, within the scope provided by the present application, the coating prepared by the corresponding ink can obtain comparable adhesion and apparent results; but if the proportion of the resin is not within the scope required by the present application, the overall performance of the obtained coating will be significantly reduced.

[0109] As can be seen from the results of Comparative Example 1 and Comparative Examples 1, 3, and 5, if the type of resin is not within the scope required by the present application, the initial adhesion of the obtained coating will not be significantly affected, but its apparent performance or high temperature and high humidity performance will be significantly reduced.

[0110] Compared with the results of Comparative Examples 1-2, it can be seen that the fluorosilicon leveling agent used in Comparative Example 2 can improve the wetting of the ink on the surface of the metal plating layer to a certain extent, thereby improving the appearance of the obtained coating; however, the fluorosilicon leveling agent will accumulate at the interface and form a weak boundary layer, thereby physically blocking and weakening the key adhesion between the ink resin and the metal plating layer, resulting in a significant decrease in performance, especially adhesion performance.

[0111] As can be seen from the results of Comparative Example 1 and Comparative Example 4, if the hydroxyl value of the aldehyde ketone resin is not within the range required by the present application, the apparent performance, i.e., the leveling effect, will decrease significantly.

[0112] According to the above analysis, it can be seen that in the ink provided by the present application, the polycarbonate resin, aldehyde ketone resin, curing agent, silane coupling agent and specific parameters of the aldehyde ketone resin in the main agent have a significant synergistic effect; all the features synergize with each other to significantly improve the leveling effect and adhesion of the ink.

[0113] In summary, the existing inks applied to metal plating layers on the market have poor performance and wetting and leveling effects, resulting in a significant reduction in the texture and gloss of the metal plating layer, poor consumer experience, and the present application provides high leveling effects while ensuring performance, providing better visual experience for consumers. Due to the above advantages, the ink provided by the present application is expected to be widely used in mobile phone cover plates with metal plating layers.

[0114] The above embodiments of the present application have been described in detail, but the present application is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. An ink, characterized by, The ink comprises a main agent, a silane coupling agent and a curing agent; The main agent comprises a polycarbonate resin, an aldehyde ketone resin and a leveling agent; The aldehyde ketone resin has a hydroxyl value of 30-150 mgKOH / g; The mass ratio of the polycarbonate resin to the aldehyde ketone resin is 5-20:55-70; The polycarbonate resin is a polycarbonate dihydric alcohol resin; The leveling agent comprises an acrylic leveling agent.

2. The ink according to claim 1, characterized in that, The polycarbonate resin has a number average molecular weight of 500-3000; And / or, the polycarbonate resin has a hydroxyl value of 30-300 mgKOH / g.

3. The ink according to claim 1, characterized in that, The curing agent comprises an isocyanate; And / or, the mass ratio of the main agent, the curing agent and the silane coupling agent is 100:5-15:1-5.

4. The ink according to any one of claims 1 to 3, characterized in that, The components of the main agent further comprise a defoaming agent and a first solvent; And / or, the components of the ink further comprise a second solvent.

5. The ink according to claim 4, characterized in that, The main agent comprises, by weight parts: The polycarbonate resin is 5-20 parts; The aldehyde ketone resin is 55-70 parts; The leveling agent is 0.5-1.5 parts; The defoaming agent is 0.2-1 part; The first solvent is 18-30 parts.

6. The ink according to claim 4, characterized in that, The ink comprises, by weight parts: The main agent is 100 parts; The curing agent is 5-15 parts; The silane coupling agent is 1-5 parts; The second solvent is 5-15 parts.

7. A method of preparing the ink according to any one of claims 1 to 6, characterized in that, The preparation method comprises the following steps: S1. Mixing the components of the main agent; S2. Mixing the product obtained in step S1 and other components of the ink.

8. Use of the ink according to any one of claims 1-6 on the surface of a metal plating layer.

9. A cover plate for a mobile phone, characterized by The cover plate comprises a substrate, a metal plating layer and an ink coating layer arranged in superposition; The preparation raw material of the ink coating layer comprises the ink according to any one of claims 1-6.

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