Hot baking type selective printing ink and preparation method thereof

Abstract

The invention relates to hot baking type selective ink and a preparation method thereof. The hot baking type selective ink comprises the following components in parts by mass: 10-20 parts of acrylic resin, 10-20 parts of fluorine-containing polyacrylate, 20-40 parts of an active monomer, 3-10 parts of a photoinitiator, 5-20 parts of modified boron nitride and 1-10 parts of an auxiliary agent, wherein the modified boron nitride is obtained by reacting boron nitride with a silane coupling agent and polypropylene glycol diglycidyl ether. The fluorine-containing polyacrylate is obtained by reacting fluorine-containing acrylate, acrylate and maleic anhydride. According to the invention, not only are the film-forming property and the stability of the ink improved, but also the corrosion resistance, the strength and other properties are enhanced, the protective effect can be more effectively exerted, the stable operation of the PCB is ensured, the problems in the prior art are solved, the requirements of the industry on multiple properties of products are met, and the application prospect is good.

Description

Technical Field

[0001] The present invention relates to the technical field of selective chemical plating inks, and particularly to a heat-bake type selective chemical plating ink and a preparation method thereof. Background Art

[0002] The surface of a PCB board needs to be subjected to selective metallization treatment to introduce a nickel-gold layer, so as to achieve the effects of conducting heat and electricity and elastic contact, making the product have a wider range of uses and higher reliability. Currently, when performing selective metallization treatment, methods such as dry film attachment, exposure, and development are usually adopted. The processes of such technologies are complex, costly, and prone to defects such as bubbles, cracking, insufficient adhesion of the film, and poor acid and alkali resistance.

[0003] Preparing a metal coating using a selective chemical plating ink can simplify the production process, reduce production costs, efficiently protect the pads and connection points on the circuit board, and prevent oxidation and corrosion. A heat-bake type selective chemical plating ink is a new type of selective chemical plating ink that realizes the hardening (curing) process through heating and baking. Its main components include resin, pigment, solvent, and additives, etc. Such products have many advantages such as simple production process, high temperature resistance, bright colors, environmental friendliness, and low VOC emissions.

[0004] However, there are still some problems with the existing heat-bake type selective chemical plating inks. For example, the adhesion is insufficient. Especially when there are impurities such as metal debris and residual oil stains on the surface of the substrate, the ink cannot form effective chemical bonds or physical adsorption with the substrate; the corrosion resistance is poor. When the ink printed matter is exposed to a corrosive environment, corrosive substances (such as acid, alkali, and salt solutions, etc.) are likely to penetrate into the ink. For example, in a high-humidity salt spray environment by the sea, chloride ions may pass through the ink layer and react chemically with the metal lines of the circuit board, resulting in circuit corrosion; the storage stability is insufficient. After long-term storage, the resin in the heat-bake type selective chemical plating ink is separated from components such as toner and filler, and phenomena such as skinning, gelling, delamination, and precipitation may occur, resulting in performance degradation.

[0005] In summary, it is necessary to develop a new technical solution to solve the deficiencies in the existing technology. Summary of the Invention

[0006] Based on this, the present invention provides a heat-bake type selective chemical plating ink and a preparation method thereof. The present invention uses substances such as acrylic resin, fluorinated polyacrylate, and modified boron nitride in combination, which not only improves the film-forming property and stability of the ink, but also enhances various properties such as corrosion resistance and strength, can play a more effective protective role, ensures the stable operation of the PCB board, and solves the problems existing in the existing technology.

[0007] An object of the present invention is to provide a heat-bake type selective chemical plating ink, and the heat-bake type selective chemical plating ink comprises components in the following parts by mass:

[0008]

[0009]

[0010] Among them,

[0011] The modified boron nitride is obtained by reacting boron nitride with a silane coupling agent and polypropylene glycol diglycidyl ether.

[0012] Further, the fluorinated polyacrylate is obtained by reacting a fluorinated acrylate, an acrylate, and maleic anhydride.

[0013] Further, the acrylic resin is a carboxyl-containing acrylic resin.

[0014] Further, the active monomer is a monomer having acrylate units with single or multiple functional groups.

[0015] Further, the silane coupling agent is an amino silane coupling agent.

[0016] Further, the auxiliary agent is selected from one or more of color powder, leveling agent, defoaming agent, dispersant, emulsifier, antioxidant, toughening agent, and curing agent.

[0017] Another object of the present invention is to provide a preparation method of the above-mentioned heat-baked type selective ink. The preparation method of the heat-baked type selective ink includes the following steps:

[0018] S1. Mix the fluorinated acrylate, acrylate, maleic anhydride, and initiator, and under an inert gas atmosphere, heat and stir to react to obtain a fluorinated polyacrylate;

[0019] S2. Mix boron nitride with a silane coupling agent, after heating and reacting, mix with polypropylene glycol diglycidyl ether, and continue to react to obtain modified boron nitride;

[0020] S3. Mix the modified boron nitride with the fluorinated polyacrylate, acrylic resin, active monomer, photoinitiator, and auxiliary agent, stir and disperse evenly, grind and filter to obtain the heat-baked type selective ink.

[0021] Further, the temperature of the heating and stirring reaction is 60 - 100 °C.

[0022] Further, the mass ratio of the fluorinated acrylate, acrylate, and maleic anhydride is (0.1 - 0.5):(1 - 3):(0.5 - 1).

[0023] Further, in step S2, the temperature of the heating and stirring reaction is 30 - 100 °C.

[0024] Furthermore, the mass ratio of the boron nitride to the polypropylene glycol diglycidyl ether is 1:(0.5 - 3).

[0025] The present invention has the following beneficial effects:

[0026] The thermal baking type electroless plating ink provided by the present invention uses various substances such as an acrylic resin containing a carboxyl group, a fluorinated polyacrylate, and a modified boron nitride as components. Among them, the fluorinated polyacrylate is polymerized from a fluorinated acrylate, an acrylic alkyl ester, and maleic anhydride, and contains rich perfluoroalkyl and anhydride groups. The introduction of the fluorocarbon chain segment effectively improves various capabilities such as heat resistance and solvent resistance of the ink protective layer. The modified boron nitride is first treated with a silane coupling agent to introduce active amino groups, and then mixed and reacted with a polypropylene glycol diglycidyl ether capped with an epoxy group. Thus, epoxy groups and propoxy chain segments are introduced into the modified boron nitride. On the one hand, this component has better dispersibility and can be persistently and uniformly distributed in the composition under the action of an emulsifier (dispersant), avoiding problems such as agglomeration, stratification, and precipitation. On the other hand, the flexible polypropylene glycol chain segment in the modified boron nitride has a hydrophobic and lipophilic function, which not only improves the compatibility with organic resins but also helps to enhance the solvent resistance and corrosion resistance of the ink. In addition, the rich active groups are not only beneficial to improving the adhesion of the ink, but the modified boron nitride can also crosslink with groups such as carboxyl groups in the acrylic resin and fluorinated polyacrylate through epoxy groups to form an interpenetrating network, further improving the stability and strength of the product and achieving a more excellent protective effect. Specific embodiments

[0027] To more clearly illustrate the technical solutions of the present invention, the following examples are listed. The raw materials, reactions, and post-treatment means appearing in the examples are all common raw materials on the market and technical means well-known to those skilled in the art, unless otherwise specified.

[0028] The terms "preferred", "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain cases. However, in the same or other cases, other embodiments may also be preferred. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of the present invention.

[0029] It should be understood that, unless in any operating example or otherwise indicated, all numbers representing the amounts of ingredients or otherwise used in the specification and claims should be understood to be modified in all instances by the term "about". Therefore, unless otherwise indicated, the numerical parameters set forth in the following specification and appended claims are approximations that vary depending upon the desired properties sought to be obtained by the present invention.

[0030] In the embodiment of the present invention, the acrylic resin is Sartomer SB520A20, and the acid value is 200 mgKOH / g (content 80%).

[0031] In the embodiment of the present invention, the reactive monomer is trimethylolpropane triacrylate (TMPTA) and dipentaerythritol hexaacrylate (DPHA) with a mass ratio of 1:1.

[0032] In the embodiment of the present invention, the photoinitiator is 819.

[0033] In the embodiment of the present invention, the additives are leveling agent isopropanol and emulsifier OP-10 (purchased from Aladdin) with a mass ratio of 1:1.

[0034] In the embodiment of the present invention, the polypropylene glycol diglycidyl ether has an Mn of about 380 and is purchased from Aladdin.

[0035] In the embodiment of the present invention, the boron nitride is pretreated by surface hydroxylation:

[0036] The boron nitride is immersed in a sufficient amount of a mixed solution of concentrated sulfuric acid and nitric acid with a volume ratio of 1:3 (concentration of concentrated sulfuric acid is 18.4 mol / L, concentration of nitric acid is 1 mol / L), ultrasonically treated at 60 °C for 5 h, and the product is obtained after washing and drying.

[0037] In the embodiment of the present invention, "parts" all refer to parts by mass.

[0038] Example 1

[0039] A heat-baked selective curing ink comprises the following components in parts by mass:

[0040]

[0041]

[0042] The preparation method of the heat-baked selective curing ink comprises the following steps:

[0043] S1. Using water as a solvent, mix methyl methacrylate hexafluorobutyl ester, butyl acrylate, maleic anhydride, emulsifier OP-10 and initiator ammonium persulfate with a mass ratio of 0.4:2:1:0.2:0.1 evenly, stir and react at 80 °C for 4 h under a nitrogen atmosphere, and obtain fluorinated polyacrylate after removing the solvent;

[0044] S2. Using absolute ethanol as a solvent, add KH550 and stir at 60 °C for 3 h, then add boron nitride and react for 3 h (KH550:boron nitride = 1:5, m / m), and obtain an intermediate product after filtration, washing and drying;

[0045] Then, the intermediate product and polypropylene glycol diglycidyl ether with a mass ratio of 1:2 are mixed and reacted at 80 °C for 1 h. After filtration, washing, and drying, modified boron nitride is obtained.

[0046] S3. According to the above mass parts, the modified boron nitride is mixed with fluorinated polyacrylate, acrylic resin, reactive monomer, photoinitiator, and additives, stirred and dispersed evenly, and ground to a fineness of <1 μm to obtain the hot-baked type selective coating ink.

[0047] Example 2

[0048] A hot-baked type selective coating ink comprises the following components in mass parts:

[0049]

[0050] The preparation method of the hot-baked type selective coating ink comprises the following steps:

[0051] S1. Using water as a solvent, methyl methacrylate hexafluorobutyl ester, butyl acrylate, maleic anhydride, emulsifier OP-10, and initiator ammonium persulfate with a mass ratio of 0.4:2:1:0.2:0.1 are mixed evenly, and stirred and reacted at 80 °C for 4 h under a nitrogen atmosphere. After removing the solvent, fluorinated polyacrylate is obtained.

[0052] S2. Using anhydrous ethanol as a solvent, KH550 is added and stirred at 60 °C for 3 h, then boron nitride is added and reacted for 3 h (KH550:boron nitride = 1:5, m / m). After filtration, washing, and drying, an intermediate product is obtained.

[0053] Then, the intermediate product and polypropylene glycol diglycidyl ether with a mass ratio of 1:2 are mixed and reacted at 80 °C for 1 h. After filtration, washing, and drying, modified boron nitride is obtained.

[0054] S3. According to the above mass parts, the modified boron nitride is mixed with fluorinated polyacrylate, acrylic resin, reactive monomer, photoinitiator, and additives, stirred and dispersed evenly, and ground to a fineness of <1 μm to obtain the hot-baked type selective coating ink.

[0055] Example 3

[0056] A hot-baked type selective coating ink comprises the following components in mass parts:

[0057]

[0058] The preparation method of the hot-baked type selective coating ink comprises the following steps:

[0059] S1. Using water as a solvent, mix hexafluorobutyl methacrylate, butyl acrylate, maleic anhydride, emulsifier OP-10, and initiator ammonium persulfate with a mass ratio of 0.4:2:1:0.2:0.1 evenly. Stir and react at 80 °C for 4 h under a nitrogen atmosphere. After removing the solvent, a fluorinated polyacrylate is obtained.

[0060] S2. Using anhydrous ethanol as a solvent, add KH550 and stir at 60 °C for 3 h. Then add boron nitride and react for 3 h (KH550:boron nitride = 1:5, m / m). After filtration, washing, and drying, an intermediate product is obtained.

[0061] Then mix the intermediate product and polypropylene glycol diglycidyl ether with a mass ratio of 1:2 and react at 80 °C for 1 h. After filtration, washing, and drying, a modified boron nitride is obtained.

[0062] S3. According to the above mass parts, mix the modified boron nitride with the fluorinated polyacrylate, acrylic resin, reactive monomer, photoinitiator, and additives, stir and disperse evenly, and grind to a fineness < 1 μm to obtain the hot-baked type selective ink.

[0063] Comparative Example 1

[0064] A hot-baked type selective ink. The difference between this comparative example and Example 1 is that the fluorinated polyacrylate is replaced with an equal mass of acrylic resin, and other components and preparation methods are the same as those in Example 1.

[0065] Comparative Example 2

[0066] A hot-baked type selective ink. The difference between this comparative example and Example 1 is that in step S2, only the intermediate product is prepared, and in step S3, the modified boron nitride is replaced with an equal mass of the intermediate product, and other components and preparation methods are the same as those in Example 1.

[0067] Comparative Example 3

[0068] A hot-baked type selective ink. The difference between this comparative example and Example 1 is that in step S2, polypropylene glycol diglycidyl ether is replaced with E44 epoxy resin (Phoenix brand), and other components and preparation methods are the same as those in Example 1.

[0069] Test Example

[0070] Perform performance tests on the hot-baked type selective inks prepared in Examples 1-3 and Comparative Examples 1-3.

[0071] The test method is as follows:

[0072] Coat the hot-baked type selective inks prepared in the examples and comparative examples on the PCB board respectively, and perform photocuring for 0.5 h (wavelength 395 nm, intensity 25.0 mW / cm 2Ultraviolet light), and then thermally cured at 150 °C for 1 h to form a 0.5 mm thick film.

[0073] Adhesion: Use a needle tip to draw a cross shape on the film respectively, then stick a cellophane tape on the scratch and pull it. Evaluate according to the following criteria:

[0074] Qualified: Not torn off or slightly torn off;

[0075] Unqualified: Torn off in large amounts.

[0076] Flexural resistance: Bend at 180° with the ink film on the outside and evaluate according to the following criteria:

[0077] Qualified: No cracks on the film;

[0078] Unqualified: Cracks on the film.

[0079] Heat resistance: Conduct a thermal shock performance test according to the method in IPC-SM-840E, and the judgment criteria are as follows:

[0080] Qualified: No bubbles or cracks;

[0081] Unqualified: Bubbles and cracks appear.

[0082] Acid resistance / alkali resistance: Immerse the PCB circuit board coated with ink in 10% sulfuric acid solution or 10% sodium hydroxide solution at 20 °C, take it out after 10 min, evaluate the state and adhesion of the coating film, and the judgment criteria are as follows:

[0083] Qualified: No change or slight change is found;

[0084] Unqualified: Swelling or swelling and peeling off on the coating film.

[0085] Film stripping property: Immerse the sample in 5% sodium hydroxide solution at 50 °C for 5 min. The judgment criteria are as follows:

[0086] Qualified: Complete film stripping;

[0087] Unqualified: The film cannot be stripped off.

[0088] The test results are shown in Table 1.

[0089] Table 1 Performance test results

[0090]

[0091]

[0092] As can be seen from Table 1, the heat-baked selective chemical conversion ink prepared in Examples 1-3 of the present invention has a smooth appearance, and at the same time, has excellent adhesion, mechanical strength, corrosion resistance and stability. In Comparative Example 1, the fluorinated polyacrylate was replaced, resulting in a decrease in the acid and alkali resistance and stability of the ink. In Comparative Examples 2-3, the modified boron nitride was replaced, causing varying degrees of reduction in the compatibility, crosslinking degree and toughness between components, resulting in the influence of multiple properties of the product, and the comprehensive performance was not ideal. In summary, the heat-baked selective chemical conversion ink of the present invention solves the defects existing in the prior art and has good application prospects.

[0093] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention.

[0094] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A hot-baking type selective ink, characterized in that: The hot-baking type selective ink comprises the following components in parts by weight: in, The modified boron nitride is obtained by reacting boron nitride with a silane coupling agent and polypropylene glycol diglycidyl ether.

2. The hot-baking selective ink according to claim 1, characterized in that: The fluorine-containing polyacrylate is obtained by reacting fluorine-containing acrylic acid ester, acrylic acid ester and maleic anhydride.

3. The hot-baking selective ink according to claim 1, characterized in that: The acrylic resin is a carboxyl-containing acrylic resin.

4. The hot-baking selective ink according to claim 1, characterized in that: The reactive monomer is a monomer having a monofunctional or multifunctional acrylate unit.

5. The hot-baking selective ink according to claim 1, characterized in that: The silane coupling agent is an aminosilane coupling agent.

6. The hot-baking selective ink according to claim 1, characterized in that: The auxiliary agent is selected from one or more of color powder, leveling agent, defoamer, dispersant, emulsifier, antioxidant, toughening agent and curing agent.

7. The method for preparing the hot-baking selective ink according to any one of claims 1 to 6, characterized in that: The method for preparing the hot-baking selected ink comprises the following steps: S1, mixing fluorinated acrylate, acrylic acid ester, maleic anhydride and an initiator, heating and stirring under an inert gas atmosphere to react, to obtain fluorinated polyacrylate; S2, mixing boron nitride with a silane coupling agent, heating for reaction, and then mixing with polypropylene glycol diglycidyl ether, and continuing the reaction to obtain modified boron nitride; S3, mixing the modified boron nitride with fluorine-containing polyacrylate, acrylic resin, active monomer, photoinitiator and auxiliary agent, stirring and dispersing them evenly, grinding and filtering, and obtaining the hot-baking type selective ink.

8. The method for preparing the hot-baking selected ink according to claim 7, characterized in that: The mass ratio of the fluorine-containing acrylate, acrylate and maleic anhydride is (0.1-0.5):(1-3):(0.5-1).

9. The method for preparing the hot-baking selected ink according to claim 7, characterized in that: In step S2, the temperature of the heating and stirring reaction is 30-100°C.

10. The method for preparing the hot-baking selected ink according to claim 7, characterized in that: The mass ratio of the boron nitride to polypropylene glycol diglycidyl ether is 1:(0.5-3).

Images