Glue-resistant ink as well as preparation method and application thereof

Abstract

The invention discloses glue-resistant ink as well as a preparation method and application thereof. The glue-resistant ink is prepared from the following raw materials: hydroxyl-terminated polyurethane resin with a linear structure, polyester resin, cyclohexanone, titanium dioxide, talcum powder and mica powder. The invention provides a white ink with super resistance to 8540 glue under a UV irradiation condition. The ink can effectively fill the vacancy of a mobile phone with a white cover plate using the 8540 glue.

Description

Technical Field

[0001] The invention belongs to the technical field of inks, and in particular relates to a glue-resistant ink and a preparation method and application thereof. Background Art

[0002] In the manufacture of smartphones and smart watches, glue, as a key bonding material, is widely used in various parts of the device, especially at the joint between the glass cover and the base. At present, acrylic glue has become one of the preferred materials in this field due to its excellent performance. First of all, acrylic glue has good waterproof performance and can effectively seal the interface between the glass and the base to prevent moisture penetration, thereby improving the durability and protection performance of the device. In addition, the rapid curing characteristics of acrylic glue enable the production efficiency to be improved during the production process, and its high temperature resistance is good, which can meet the needs of long-term use of equipment in high temperature environments, further enhancing the reliability of the product. However, although acrylic glue performs well in many aspects, there are still some challenges in the actual application process. Especially when in contact with coating materials such as ink, acrylic glue easily penetrates into the ink, which may cause uneven coloring on the glass surface under UV irradiation, which is manifested as a significant difference in color between the glue-dispensing area and the non-glue-dispensing area. This heterochromatic phenomenon affects the appearance quality. At present, most white inks on the market cannot pass the key process of UV aging when used with 8540 glue (acrylic glue), resulting in obvious glue marks or color differences in the glue-dotting area, seriously affecting the overall consistency and visual effect of the appearance. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention provides a white ink that is super resistant to 8540 glue under UV irradiation conditions, and the ink can effectively fill the gap in mobile phones that use 8540 glue white cover plates.

[0004] The invention also provides a method for preparing the glue-resistant ink.

[0005] The present invention also provides an application of the glue-resistant ink in an electronic device housing.

[0006] According to a first aspect of the present invention, a glue-resistant ink is provided, wherein the raw materials for preparing the ink include: a linear hydroxyl-terminated polyurethane resin, a polyester resin, cyclohexanone, titanium dioxide, talc powder and mica powder.

[0007] According to the first aspect of the present invention, there are at least the following beneficial effects:

[0008] The glue is blocked by adding a combination of polyurethane resin and polyester. The linear hydroxyl-terminated polyurethane resin is a plastic material that has already reacted. There are no additional groups that need to react under subsequent heating conditions, which can effectively reduce the gaps between molecules. The matte effect on the surface of the polyurethane resin can effectively absorb some of the glue molecules that have penetrated. In addition, the addition of a certain amount of polyester resin can form a chemical bond (Si-O) with the glass during the reaction with isocyanate, forming excellent adhesion.

[0009] The glue-resistant ink prepared by the present invention has the following advantages: 1. Excellent screen printing appearance and strong adhesion; 2. High hiding power (OD value can reach above 2.0 when the thickness of four-layer white film is 30 μm); 3. Excellent 8540 glue resistance and water resistance.

[0010] In some embodiments of the present invention, the linear structure hydroxyl terminated polyurethane resin includes resin 6826.

[0011] In some embodiments of the present invention, the glass transition temperature of the linear hydroxyl-terminated polyurethane resin is 20 to 30°C.

[0012] Under the above conditions, the glass transition temperature of the polyurethane resin allows the resin to maintain good elasticity when exposed to ultraviolet light, thereby preventing the material from becoming brittle or cracking under long-term UV exposure.

[0013] In some embodiments of the present invention, the molecular weight of the polyester resin is 7000-8000.

[0014] In some embodiments of the present invention, the polyester resin has a glass transition temperature of 20 to 30°C.

[0015] The polyester resin with the above molecular weight and glass transition temperature ensures the flexibility and adaptability of the ink.

[0016] In some embodiments of the present invention, the polyester resin comprises resin 6896-70D.

[0017] In some embodiments of the present invention, the preparation raw materials include, by weight: 5 to 15 parts of a linear hydroxyl-terminated polyurethane resin, 5 to 15 parts of a polyester resin, 5 to 15 parts of cyclohexanone, 30 to 50 parts of titanium dioxide, 3 to 8 parts of talc and 3 to 8 parts of mica powder.

[0018] In some embodiments of the present invention, the titanium dioxide includes R-900.

[0019] In some embodiments of the present invention, the glass transition temperature of the linear hydroxyl-terminated polyurethane resin is 20 to 30°C.

[0020] In some embodiments of the present invention, the polyester resin has a glass transition temperature of 20 to 30°C.

[0021] In some embodiments of the present invention, the molecular weight of the polyester resin is 7000-8000.

[0022] In some embodiments of the present invention, the particle size of the mica powder is 10 to 15 μm.

[0023] In some embodiments of the present invention, the particle size of the titanium dioxide is 0.4-0.5 μm.

[0024] In some embodiments of the present invention, the particle size of the talc is 7 to 9 μm.

[0025] In some embodiments of the present invention, the weight ratio of the titanium dioxide, the talc and the mica powder is 8:1:1.

[0026] The combination of the above particle sizes and proportions can effectively reduce the penetration rate of glue. Through the combination of resin and powder particle size, the glue resistance and adhesion performance of the ink under UV irradiation conditions are greatly improved, which is beneficial to the combination of ink and substrate, and can ensure that the front side of the glass remains intact for a long time under UV irradiation, and there will be no offset printing due to glue penetration.

[0027] In some embodiments of the present invention, the raw materials for preparing the glue-resistant ink further include: an auxiliary agent.

[0028] In some embodiments of the present invention, the auxiliary agent includes a defoaming agent and a leveling agent.

[0029] In some embodiments of the present invention, the defoaming agent comprises a silicon-free defoaming agent.

[0030] In some embodiments of the present invention, the leveling agent includes a fluorocarbon modified polyacrylate type leveling agent.

[0031] The introduction of modified polyacrylate type leveling agent and silicone-free defoaming agent can effectively avoid abnormal adhesion caused by recoating, and can effectively improve problems such as scattered oil and bubbles in the paint film printing process, making the paint film more evenly distributed on the surface of the material.

[0032] According to a second aspect of the present invention, a method for preparing the glue-resistant ink is provided, comprising the following steps:

[0033] S1: mixing and dispersing the polyurethane resin and cyclohexanone and cooling them to obtain a dispersion;

[0034] S2: Add polyester resin, titanium dioxide, talcum powder and mica powder to the dispersion obtained in step S1, and mix and grind.

[0035] According to a third aspect of the present invention, a method for preparing the glue-resistant ink is provided, comprising the following steps:

[0036] S1: mixing and dispersing the polyurethane resin and cyclohexanone and cooling them to obtain a dispersion;

[0037] S2: adding polyester resin, titanium dioxide, talcum powder and mica powder to the dispersion obtained in step S1, mixing, dispersing and grinding;

[0038] S3: Disperse the ground product from step S2 with defoamer and leveling agent at 600-800 r / min for 20-30.

[0039] In some embodiments of the present invention, in step S1, the dispersing step further comprises adding a solvent.

[0040] In some embodiments of the present invention, in step S1, the solvent includes a dibasic ester.

[0041] In some embodiments of the present invention, the preparation raw materials include, by weight: 5 to 15 parts of a linear hydroxyl-terminated polyurethane resin, 5 to 15 parts of a dibasic ester, 5 to 15 parts of a polyester resin, 5 to 15 parts of cyclohexanone, 30 to 50 parts of titanium dioxide, 3 to 8 parts of talc and 3 to 8 parts of mica powder.

[0042] In some embodiments of the present invention, in step S2, the dispersing step further includes adding a dispersant.

[0043] In some embodiments of the present invention, the preparation raw materials include, by weight: 5 to 15 parts of a linear hydroxyl-terminated polyurethane resin, 5 to 15 parts of a dibasic ester, 5 to 15 parts of a polyester resin, 2 to 5 parts of a dispersant, 5 to 15 parts of cyclohexanone, 30 to 50 parts of titanium dioxide, 3 to 8 parts of talc and 3 to 8 parts of mica powder.

[0044] In some embodiments of the present invention, in step S1, the temperature of the mixing and dispersing is 40-60°C.

[0045] The mixture obtained in the above step S3 is component A of the glue-resistant ink.

[0046] In some embodiments of the present invention, the glue-resistant ink further comprises a curing agent, a coupling agent and a diluent.

[0047] In some embodiments of the present invention, the curing agent comprises a polyester amine curing agent.

[0048] The curing agent is used as the B component of the glue-resistant ink.

[0049] In some embodiments of the present invention, the polyesteramine curing agent includes TAKENATE D-110N.

[0050] The selection of the above curing agent can achieve rapid surface drying and effectively shorten the waiting time during the construction process.

[0051] In some embodiments of the present invention, the coupling agent comprises an amino-functional silane coupling agent.

[0052] The coupling agent is used as the C component of the glue-resistant ink.

[0053] In some embodiments of the present invention, the amino-functional silane coupling agent comprises Dynasylan DAMO-T.

[0054] In some embodiments of the present invention, the diluent includes an alcohol ether diluent.

[0055] The above diluent is used as the D component of the glue-resistant ink.

[0056] In some embodiments of the present invention, the alcohol ether diluent includes dipropylene glycol methyl ether acetate.

[0057] The addition of the above-mentioned diluent can effectively improve the problem of dry mesh during the construction process.

[0058] According to a third aspect of the present invention, application of glue-resistant ink in electronic equipment housing is proposed. DETAILED DESCRIPTION

[0059] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0060] The 6826 polyurethane resin in the present invention was purchased from Lingling Chenguang;

[0061] 6896-70D was purchased from Guolong;

[0062] R-900 was purchased from DuPont;

[0063] 3000 mesh talcum powder was purchased from Guangdong Shenpeng Powder;

[0064] R972 was purchased from Degussa Gas Silicon;

[0065] TAKENATE D was purchased from Covestro;

[0066] Dynasylan DAMO-T was purchased from Evonik.

[0067] Example 1

[0068] This embodiment prepares a glue-resistant ink, and the specific component contents are shown in Table 1. The specific steps are as follows:

[0069] S1. Add 6826 polyurethane resin, cyclohexanone and DBE to the ink reaction kettle in sequence, stir at 800r / min for 30 minutes (temperature controlled below 60°C), and after confirming that there is no obvious granular solid resin, stop stirring and cool to below 40°C;

[0070] S2. Add corresponding proportions of resin 2, BYK163, R-900, mica powder, talcum powder and R972 on the basis of step S1, stir at 600-800r / min for 20-30 minutes, let stand for more than 12 hours, and grind in a three-roll mill or a high-viscosity sand mill; the number of grinding times and grinding time are determined according to the grinding fineness. When the grinding fineness is less than 10μm, remove the ink;

[0071] S3. Add corresponding proportions of BYK054, isophorone, and EFKA FL 3600 (leveling agent) in step S2, and stir at 600 to 800 r / min for 20 to 30 minutes;

[0072] S4. After the three components A / B / C / D are mixed in proportion, four layers are printed using a 250-mesh polyester screen. The first three layers are baked at 150℃ for 5 minutes, and the last layer is baked at 150℃ for 30 minutes. After the appearance, color and performance meet the requirements, it is packaged and shipped.

[0073] Example 2

[0074] This embodiment prepares a glue-resistant ink. The difference between this embodiment and embodiment 1 is that the feeding amount of each component is different, as shown in Table 1.

[0075] Example 3

[0076] This embodiment prepares a glue-resistant ink. The difference between this embodiment and embodiment 1 is that the feeding amount of each component is different, as shown in Table 1.

[0077] Example 4

[0078] This embodiment prepares a glue-resistant ink. The difference between this embodiment and embodiment 1 is that the feeding amount of each component is different, as shown in Table 1.

[0079] Example 5

[0080] This embodiment prepares a glue-resistant ink. The difference between this embodiment and embodiment 1 is that the amount of titanium dioxide used is 45 parts, and the other conditions are the same.

[0081] Comparative Example 1

[0082] This comparative example prepares a glue-resistant ink. The difference between this comparative example and Example 1 is that the feeding amounts of each component are different, as shown in Table 1.

[0083] Comparative Example 2

[0084] This comparative example prepares a glue-resistant ink. The difference between this comparative example and Example 1 is that the feeding amounts of each component are different, as shown in Table 1.

[0085] Comparative Example 3

[0086] This comparative example prepares a glue-resistant ink. The difference between this comparative example and Example 1 is that the feeding amounts of each component are different, as shown in Table 1.

[0087] Comparative Example 4

[0088] In this comparative example, a glue-resistant ink is prepared. The difference between this comparative example and Example 1 is that the linear hydroxyl-terminated polyurethane resin in Example 1 is replaced by BH-PUV-2100A, and the other conditions are the same.

[0089] Comparative Example 5

[0090] This comparative example prepares a glue-resistant ink. The difference between this comparative example and Example 1 is that the polyester resin in Example 1 is replaced by A-472, and the other conditions are the same.

[0091] Table 1. Components of glue-resistant inks of Examples and Comparative Examples

[0092]

[0093]

[0094]

[0095]

[0096] Test Case

[0097] This test example tests the test data of the low VOC white coating used on the mobile phone glass of the embodiment and the comparative example, and the results are shown in Table 2:

[0098] Note: Test standard and instrument:

[0099] The adhesion test standard refers to "GBT1720-79 Paint Film Adhesion Determination Method".

[0100] Film thickness testing instrument: Japan Mitutoyo thin-film micrometer No. 293-240-30.

[0101] 8540 glue test method: Mix AB glue of 8540 glue evenly on the finished sample and then apply glue, then cover it with transparent glass material, and then press a 200g weight on it, put it in a 60℃ oven and bake for 20 minutes; take out the sample, place it with the glass side facing up under the conditions of 340nm, 0.55w / cm2, irradiate for 72 hours, and observe whether it contains offset printing.

[0102] Table 2. Performance test

[0103]

[0104]

[0105] In comparative example 1, the ink contains only 6826 polyurethane resin. When the resin is used alone, the polyurethane resin itself has been reacted, and the groups in the structure are basically closed, and it is impossible to form a chemical bond between the resin and the material through subsequent heating and curing agent reactions.

[0106] The reason for the slight offset in Comparative Example 2 is that there is only 6896-70D polyester resin (curing requires hydroxyl and isocyanate for cross-linking) in the ink. When this resin is used alone, the curing and cross-linking effect is worse than that of 6826 polyurethane (during curing, the isocyanate curing agent only plays the role of filling the gaps between the components and generating adhesion with the material), resulting in insufficient glue resistance; the reason for the slight offset in Comparative Example 3 is the lack of mica powder filler. Mica powder filler is a flaky filler that will form a planar structure barrier layer in the ink, which is helpful in preventing the penetration of glue.

[0107] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A glue-resistant ink, characterized in that: The preparation raw materials include: linear hydroxyl-terminated polyurethane resin, polyester resin, cyclohexanone, titanium dioxide, talcum powder and mica powder.

2. The glue-resistant ink according to claim 1, characterized in that: The glass transition temperature of the linear hydroxyl-terminated polyurethane resin is 20-30°C.

3. The glue-resistant ink according to claim 1, characterized in that: The glass transition temperature of the polyester resin is 20-30° C.; and / or the molecular weight of the polyester resin is 7000-8000.

4. The glue-resistant ink according to claim 1, characterized in that: The particle size of the mica powder is 10 to 15 μm.

5. The glue-resistant ink according to claim 1, characterized in that: The particle size of the titanium dioxide is 0.4-0.5 μm.

6. The glue-resistant ink according to claim 1, characterized in that: The particle size of the talc powder is 7 to 9 μm.

7. The glue-resistant ink according to claim 1, characterized in that: The raw materials for preparing the glue-resistant ink also include: an auxiliary agent; and / or the auxiliary agent includes a defoaming agent and a leveling agent.

8. A method for preparing the glue-resistant ink according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: mixing and dispersing the polyurethane resin and cyclohexanone and cooling them to obtain a dispersion; S2: Add polyester resin, titanium dioxide, talcum powder and mica powder to the dispersion obtained in step S1, and mix, disperse and grind.

9. The method for preparing the glue-resistant ink according to claim 8, characterized in that: In step S1, the temperature of the mixing and dispersing is 40-60°C.

10. Use of the glue-resistant ink according to any one of claims 1 to 7 in an electronic device housing.

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