Water-soluble ink as well as preparation method and application thereof

Abstract

The invention discloses water-soluble ink which comprises the following components in parts by weight: 40-80 parts of water-soluble resin, 10-20 parts of filler, 0-1 part of a defoaming agent, 0-1 part of a flatting agent, 5-20 parts of a solvent and 0-3 parts of a thickening agent, and the water-soluble ink is washed with hot water at 20-100 DEG C after being cured. The water-soluble ink has high hardness after being cured, can provide strong supporting force and inhibit burrs in the milling process when being coated on a PCB (Printed Circuit Board) containing a golden finger, is easy to wash, does not cause damage to the PCB golden finger board, and can be widely applied.

Description

Technical Field

[0001] The invention relates to the technical field of printed circuit board gong plate processing, and in particular to a water-soluble ink and a preparation method and application thereof. Background Art

[0002] With the development of optical communication technology, electronic plug-ins are also developing rapidly. Gold fingers provide low contact resistance for the contact between separated devices and other hardware. The quality of gold fingers also directly affects the connection performance of two PCB parts, thus affecting the entire product. Therefore, the industry has higher and higher quality requirements for gold fingers. In order to facilitate plugging and unplugging, the gold fingers of PCB boards are usually treated with immersion gold / gold plating, and the copper-free areas are not covered with green oil. However, in the gong plate process after immersion gold and gold plating, two heterogeneous materials are milled at the same time, resulting in uneven deformation: 1. The base material composed of glass fiber resin is prone to cracking, causing the gold finger layer to fall off; 2. Under the cutting action of the milling cutter, the gold fingers are squeezed and deformed and are not easy to be cut off, and eventually form thread-like burrs. The simultaneous milling of the above two heterogeneous materials will eventually lead to burrs at the gold fingers of the PCB board, which will cause major quality problems for this type of product.

[0003] These burrs may affect the performance and reliability of the circuit board, causing the burr to fall off during welding, seriously causing welding short circuit and scrapping, and also affecting the connection and transmission signal of the gold finger. At present, the industry has solved the burrs of the gold finger: 1. Use a tool to cut forward and backward, and cut from both ends of the PCB gold finger board respectively, and each time the knife is gonged, it does not exceed the other end of the gold finger, ensuring that the tool always maintains a reverse support force during the cutting process, solving the problem of bevel edge burr; 2. Use the initial blind gong to process the angle and depth of the bevel, and perform a secondary blind gong, using a flat-head milling cutter and the board surface to cut off the gold finger guide line vertically to remove the burrs. Through two blind gongs, the burrs caused by the gold finger guide line are removed. At present, the industry generally uses different milling cutters and adjusts the gong plate parameters to achieve the purpose of suppressing the gold finger guide line burrs, but there are great limitations, such as only being able to suppress the generation of gold finger guide line burrs for specific PCB gold finger boards, and being unable to fundamentally solve the generation of gold finger guide line burrs, and the operation is complicated and the cost is high. The burrs usually need to be repaired manually, and manual repair will inevitably scratch the gold finger and make it scrapped due to uneven force applied by different people. In addition, the entire repair process of manually repairing the gold finger guide burrs is slow, inefficient, and cumbersome. The amount of scratches is bound to increase, and major quality problems are prone to occur. The prior art also discloses a method for improving the gold finger guide traces of CNC cutting of PCB boards by coating anti-plating resin, which can play a role in reinforcing and protecting the gold finger guide traces, so that the force is evenly applied during CNC cutting of gold finger guide traces, and the problems of burring and wire warping are solved. However, the anti-plating resin used needs to be cured with a hot alkaline solution to complete the film removal. Such chemical agents will cause irreversible damage to the PCB gold finger board, so it has not yet been widely used in the industry.

[0004] Therefore, it is urgent to develop an ink that can be coated on the PCB board to reinforce the gold finger guide line to avoid flashing and can be easily washed off. Summary of the invention

[0005] In view of the defects in the prior art, the present invention provides a water-soluble ink and a preparation method and application thereof.

[0006] The present invention provides a water-soluble ink, which comprises the following components in parts by weight: 40-80 parts of a water-soluble resin, such as 40, 45, 50, 55, 60, 65, 70, 75, and 80 parts; 10-20 parts of a filler, such as 10, 12, 14, 16, 18, and 20 parts; 0-1 part of a defoaming agent, such as 0, 0.1, 0.2, 0.4, 0.6, 0.8, and 1.0 parts; 0-1 part of a leveling agent, such as 0, 0.1, 0.2, 0.4, 0.6, 0.8, and 1.0 parts; 5-20 parts of a solvent, such as 5, 10, 15, and 20 parts; 0-3 parts of a thickener, such as 0, 1, 1.5, 2, 2.5, and 3 parts; and after the water-soluble ink is cured, it is washed out with hot water at 20 to 100°C.

[0007] The generation of gold finger line burrs is due to the uneven deformation of two heterogeneous materials when being milled at the same time. In order to ensure that the gold fingers of the PCB gold finger board are in the process of being milled, the metal surface and the non-metal surface will not generate burrs due to uneven force. The present invention develops a water-soluble ink. After curing, this water-soluble ink has a certain adhesion on the metal and non-metal surfaces, and can be coated on both sides of the PCB gold finger board to ensure that the PCB gold finger board is provided with a certain support force when being milled, so as to avoid the metal surface and the non-metal surface from generating burrs due to uneven force.

[0008] The water-soluble ink developed by the present invention can improve the problem of gold finger line burrs. The ink has strong adhesion and hardness on metals and non-metals, which can effectively inhibit the generation of gold finger line burrs. At the same time, it can also protect the surface of the PCB gold finger plate to a certain extent, preventing the generation of surface scratches and scratches. After the gong plate processing is completed, the ink can be simply used with hot water to quickly fade the film, leaving no residue on the PCB gold finger plate, and will not cause damage to the PCB gold finger plate or cause pollution. The present invention can fundamentally solve the generation of gold finger line burrs, avoid the problem of burrs falling off during welding caused by gold finger line burrs, and solve the problems of PCB gold finger plate surface scratches and scratches caused by manual burr processing.

[0009] Furthermore, the water-soluble resin is any one or more of a water-based pure acrylic resin or a modified resin thereof, a water-based polyurethane acrylic resin or a modified resin thereof, a water-based polyester acrylic resin or a modified resin thereof, and a water-based silicone resin or a modified resin thereof; the specific resin molecular structure used in the present invention contains a large number of hydrophilic groups, such as carboxylic acid groups, hydroxyl groups, etc., which can be dissolved or swelled in water to form an aqueous solution or a dispersed system.

[0010] Furthermore, the filler is any one or more of talc, calcium carbonate, glass powder or silica powder.

[0011] Furthermore, the average particle size of the filler is 1500-5000 mesh.

[0012] Furthermore, the solvent is any one or more of water, ethanol, dibasic lipid, propylene glycol methyl ether or propylene glycol methyl ether acetate; preferably water or dibasic lipid.

[0013] Furthermore, the defoaming agent includes but is not limited to any one of an organic silicon defoaming agent, a non-silicon defoaming agent or a polyether defoaming agent.

[0014] Furthermore, the leveling agent includes but is not limited to any one of an acrylic leveling agent and a fluorine-modified acrylate.

[0015] Furthermore, the thickener includes but is not limited to any one of fumed silica, alkali swelling thickener or polyurethane thickener.

[0016] The present invention also provides a method for preparing the water-soluble ink, comprising the following steps:

[0017] After the water-soluble resin and the solvent are uniformly mixed in a container by weight, a high-speed disperser is used to stir them evenly at 1000-1200 rpm, and then a defoamer, a leveling agent and a thickener are weighed and added by weight and stirred evenly, and finally a filler is added by weight and dispersed at a high speed at 1200-1500 rpm to stir it evenly, so as to obtain the water-soluble ink.

[0018] The present invention also provides application of the water-soluble ink in processing PCB gold finger plate and gong plate.

[0019] Furthermore, the water-soluble ink is used in the processing of PCB gold finger board and gong board, and the usage method is as follows: the water-soluble ink is coated on both sides of the PCB gold finger board, the coated PCB gold finger board is baked to solidify the ink, and the gong board is performed, and the water-soluble ink is washed off after the gong board.

[0020] Furthermore, the coating method is any one of screen printing, roller coating or spraying.

[0021] Furthermore, the curing temperature is 20-150° C., and the curing time is 10-60 min.

[0022] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0023] (1) The water-soluble ink provided by the present invention has strong support and high hardness after curing;

[0024] (2) After the water-soluble ink provided by the present invention is cured, it can be directly washed out with water without any residue and without causing damage to the PCB gold finger board;

[0025] (3) The preparation method of the water-soluble ink provided by the present invention is simple, and the operation process is simple when used for PCB gold finger boards, which can save costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 The schematic diagram is a structural diagram of the water-soluble ink of the present invention after being coated on the gold finger board.

[0028] Figure numerals: 1- water-soluble ink coating; 2- PCB gold finger board. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0030] Example

[0031] The present invention is further described below in conjunction with specific examples and comparative examples. The following specific examples are all preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and are particularly not limited to the types of the various component raw materials used in the following specific examples.

[0032] 1. The sources of raw materials for the embodiments and comparative examples are as follows:

[0033] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present invention are commercially available.

[0034] The preparation method of the water-soluble ink comprises the following steps:

[0035] After the water-soluble resin and the solvent are uniformly mixed in the ink tank by weight, a high-dispersing machine is used to stir them evenly at 1000-1200 rpm, and then a defoamer, a leveling agent and a thickener are weighed and added by weight and stirred evenly, and finally a filler is added by weight and dispersed at a high speed at 1200-1500 rpm to stir it evenly, so as to obtain the water-soluble ink.

[0036] 2. Various performance test methods

[0037] (1) Hardness test of water-soluble ink after curing: Test according to the national standard GB 6739-86 "Coating Hardness Pencil Hardness Method".

[0038] (2) Test of PCB board gold finger burr condition: Observe the burr length of the gold finger after cutting through a microscope. The burr size is less than 20μm.

[0039] (3) Water-soluble ink fading test: Visually inspect whether there is any residual coating on the PCB gold finger surface after fading and whether the surface is damaged.

[0040] Example 1

[0041] Embodiment 1 provides a water-soluble ink, comprising the following components in parts by weight:

[0042]

[0043] Example 2

[0044] Embodiment 2 provides a water-soluble ink, comprising the following components in parts by weight:

[0045]

[0046]

[0047] Example 3

[0048] This case provides a water-soluble ink, which includes the following components by percentage:

[0049]

[0050] Example 4

[0051] Embodiment 4 provides a water-soluble ink, comprising the following components by weight:

[0052]

[0053] Comparative Example 1

[0054] Comparative Example 1 is a commercially available solder resist ink.

[0055] The water-soluble ink or commercially available ink prepared above is stirred evenly, and then coated on a PCB board containing gold fingers. After coating, the dry film thickness (single layer thickness) is controlled to be about 50 μm, and the ink is baked and cured. After the ink is cured, the other side of the PCB board is also coated with ink, and the dry film thickness is also controlled to be about 50 μm. After complete curing, a gong board test is performed. After the gong board is completed, 50°C hot water is used to remove the film, and the burrs at the gold fingers of the PCB board are observed under a microscope and the burr size is measured. Comparative Example 2 is a PCB board containing gold fingers that is not coated with any ink.

[0056] Table 1 Effects of Examples and Comparative Examples

[0057]

[0058] The water-soluble ink of Examples 1-4 also contains specific water-soluble resins, fillers, defoaming agents, leveling agents, solvents and thickeners. The prepared water-soluble ink has high hardness after curing, can inhibit the generation of burrs during the gong process of PCB boards containing gold fingers, and after the gong is completed, the water-soluble ink can be completely washed off in hot water at 50°C, which is easy to operate and conducive to large-scale applications.

[0059] In Comparative Examples 1-2, Comparative Example 1 uses commercially available ink to coat the PCB board containing gold fingers. During the fading process, hot water cannot be used directly for fading, and hot alkaline solution is required to completely fading, which causes the PCB gold finger board to be damaged under the influence of chemical reagents after fading, which has a certain impact on product performance; Comparative Example 2 does not coat the water-soluble ink of the present application on the PCB board containing gold fingers, and the phenomenon of burrs generated during the gong process is more serious, which is not conducive to subsequent processing. The above comparative examples cannot suppress the generation of burrs on the PCB board containing gold fingers during the gong process and ensure that they can be easily faded without affecting the PCB gold finger board.

[0060] Based on the test data in Table 1 on the hardness of the water-soluble ink after curing, the burr suppression effect on the PCB board containing gold fingers, and the fading condition, the water-soluble ink prepared by Examples 1-4 has obvious advantages over the comparative example and can effectively meet the high standards of customers and the market.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A water-soluble ink, characterized in that: By weight, it includes the following components: After the water-soluble ink is cured, it is washed out with hot water at 20-100°C.

2. The water-soluble ink according to claim 1, characterized in that: The water-soluble resin is any one or more of water-based pure acrylic resin or its modified resin, water-based polyurethane acrylic resin or its modified resin, water-based polyester acrylic resin or its modified resin, and water-based silicone resin or its modified resin.

3. The water-soluble ink according to claim 1, characterized in that: The filler is any one or more of talc, calcium carbonate, glass powder or silica powder.

4. The water-soluble ink according to claim 3, characterized in that: The average particle size of the filler is 1500-5000 mesh.

5. The water-soluble ink according to claim 1, characterized in that: The solvent is any one or more of water, ethanol, dibasic lipids, propylene glycol methyl ether or propylene glycol methyl ether acetate.

6. The method for preparing the water-soluble ink according to any one of claims 1 to 5, characterized in that: The following steps are involved: After the water-soluble resin and the solvent are uniformly mixed in a container by weight, a high-speed disperser is used to stir them evenly at 1000-1200 rpm, and then a defoamer, a leveling agent and a thickener are weighed and added by weight and stirred evenly, and finally a filler is added by weight and dispersed at a high speed at 1200-1500 rpm to stir it evenly, so as to obtain the water-soluble ink.

7. Application of the water-soluble ink according to any one of claims 1 to 5 in the processing of PCB gold finger plate gong plate.

8. The use of the water-soluble ink according to claim 7, characterized in that: The usage is as follows: apply water-soluble ink on both sides of the PCB gold finger board, bake the coated PCB gold finger board to solidify the ink, perform gong board, and then wash off the water-soluble ink.

9. The use of the water-soluble ink according to claim 8, characterized in that: The coating method is any one of screen printing, roller coating or spraying.

10. The use of the water-soluble ink according to claim 8, characterized in that: The baking and curing temperature is 20-150° C., and the baking time is 10-60 min.

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