A kind of hot baking type selective chemical ink and preparation method thereof

Abstract

The present invention relates to a hot-baked selective ink and a preparation method thereof. The hot-baked selective ink comprises the following components by weight: 10-20 parts of an acrylic resin, 10-20 parts of a fluorinated polyacrylate, 20-40 parts of an active monomer, 3-10 parts of a photoinitiator, 5-20 parts of a 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 fluorinated polyacrylate is obtained by reacting a fluorinated acrylic ester, an acrylic ester, and maleic anhydride. The present invention not only improves the film-forming property and stability of the ink, but also enhances various properties such as corrosion resistance and strength, enabling more effective protective effects and ensuring stable operation of printed circuit boards. This solves problems existing in the prior art, meets industry demands for multiple product performance, and has promising application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of selective chemical ink, in particular to a hot-baked selective chemical ink and a preparation method thereof. Background Art

[0002] PCB surfaces require selective metallization to introduce a nickel-gold layer, achieving electrical conductivity, heat transfer, and elastic contact, broadening product applications and increasing reliability. Currently, selective metallization typically involves dry film lamination, exposure, and development. This process is complex, costly, and prone to defects such as bubbles, cracking, insufficient film adhesion, and poor acid and alkali resistance.

[0003] Using selective chemical inks to create metal coatings can simplify production processes, reduce costs, and effectively protect pads and connections on circuit boards from oxidation and corrosion. Thermally cured selective chemical inks, primarily composed of resins, pigments, solvents, and additives, are a new type of selective chemical ink that hardens (cures) through heating. These products offer numerous advantages, including simple production processes, high-temperature resistance, vibrant colors, environmental friendliness, and low VOC emissions.

[0004] However, existing hot-baking selective inks still have some problems, such as: insufficient adhesion, especially when there are impurities such as metal debris and residual oil on the surface of the substrate, the ink cannot form an effective chemical bond or physical adsorption with the substrate; poor corrosion resistance, when the ink printed matter is exposed to a corrosive environment, corrosive substances (such as acids, alkalis, salt solutions, etc.) can easily penetrate into the ink, such as in the high humidity salt spray environment at the seaside, chloride ions may pass through the ink layer and chemically react with the metal circuits of the circuit board, causing circuit corrosion; insufficient storage stability, after long-term storage, the resin in the hot-baking selective ink separates from the toner, filler and other components, and may cause crusting, gelation, stratification, precipitation and other phenomena, 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-cured selective ink and its preparation method. This invention utilizes a compound of acrylic resin, fluorinated polyacrylate, and modified boron nitride to improve the ink's film-forming properties and stability, while also enhancing its corrosion resistance, strength, and other properties. This allows for more effective protection, ensuring stable operation of PCBs and resolving existing issues.

[0007] One object of the present invention is to provide a heat-cured selective ink, wherein the heat-cured selective ink comprises the following components in parts by weight:

[0008]

[0009]

[0010] in,

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

[0012] Furthermore, the fluorine-containing polyacrylate is obtained by reacting fluorine-containing acrylate, acrylate and maleic anhydride.

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

[0014] Furthermore, the reactive monomer is a monomer having a monofunctional or multifunctional acrylate unit.

[0015] Furthermore, the silane coupling agent is an aminosilane coupling agent.

[0016] Furthermore, 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 method for preparing the above-mentioned hot-baking type selective ink, the method comprising the following steps:

[0018] 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;

[0019] 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;

[0020] S3. Mix the modified boron nitride with fluorine-containing polyacrylate, acrylic resin, active monomer, photoinitiator and auxiliary agent, stir and disperse them evenly, grind and filter them to obtain the hot-baking selected ink.

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

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

[0023] Furthermore, 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 polypropylene glycol diglycidyl ether is 1:(0.5-3).

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

[0026] The heat-curable selective ink provided by the present invention utilizes a variety of components, including a carboxyl-containing acrylic resin, a fluorinated polyacrylate, and modified boron nitride. The fluorinated polyacrylate is a polymerized product of a fluorinated acrylic acid ester, an alkyl acrylate, and maleic anhydride. It contains abundant polyfluoroalkyl and anhydride groups. The introduction of fluorocarbon segments effectively enhances the heat and solvent resistance of the ink's protective layer. The modified boron nitride is first treated with a silane coupling agent to introduce active amino groups, and then mixed with epoxy-terminated polypropylene glycol diglycidyl ether to react, thereby introducing epoxy and propoxy chain segments into the modified boron nitride. On the one hand, this component has better dispersibility and can be persistently and evenly distributed in the composition under the action of an emulsifier (dispersant), avoiding problems such as agglomeration, stratification, and precipitation. On the other hand, the polypropylene glycol flexible chain segment in the modified boron nitride has hydrophobic and lipophilic functions, 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 not only help improve the adhesion of the ink, but the modified boron nitride can also cross-link with groups such as carboxyl groups in acrylic resins and fluorinated polyacrylates through epoxy groups to form an interpenetrating network, further improving the stability and strength of the product and achieving a more excellent protective effect. DETAILED DESCRIPTION

[0027] In order to more clearly illustrate the technical solutions of the present invention, the following examples are given. Unless otherwise stated, the raw materials, reactions and post-processing methods mentioned in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0028] The terms "preferred," "preferably," "more preferred," and the like, used herein, refer to embodiments of the invention that may provide certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

[0029] It should be understood that, except in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties to be obtained by the present invention.

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

[0031] The active monomers in the embodiment of the present invention are trimethylolpropane triacrylate (TMPTA) and polydipentaerythritol hexaacrylate (DPHA) in a mass ratio of 1:1.

[0032] The photoinitiator in the embodiment of the present invention is 819.

[0033] The auxiliary agent in the embodiment of the present invention is a leveling agent isopropyl alcohol and an emulsifier OP-10 (purchased from Aladdin) in a mass ratio of 1:1.

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

[0035] The boron nitride in the embodiment of the present invention is subjected to surface hydroxylation pretreatment:

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

[0037] The “parts” in the embodiments of the present invention refer to parts by mass.

[0038] Example 1

[0039] A heat-baking selective ink comprising the following components in parts by weight:

[0040]

[0041]

[0042] The preparation method of the hot-baking selected ink comprises the following steps:

[0043] S1. Using water as solvent, hexafluorobutyl methacrylate, butyl acrylate, maleic anhydride, emulsifier OP-10, and initiator ammonium persulfate in a mass ratio of 0.4:2:1:0.2:0.1 were mixed evenly, and stirred at 80° C. under nitrogen atmosphere for 4 h. After removing the solvent, fluorinated polyacrylate was obtained;

[0044] S2. Using anhydrous ethanol as solvent, add KH550 and stir at 60°C for 3 hours, then add boron nitride and react for 3 hours (KH550:boron nitride=1:5, m / m), filter, wash, and dry to obtain an intermediate product;

[0045] Then, the intermediate product and polypropylene glycol diglycidyl ether in a mass ratio of 1:2 were mixed, reacted at 80° C. for 1 hour, filtered, washed, and dried to obtain modified boron nitride;

[0046] S3. According to the above-mentioned mass fractions, the modified boron nitride is mixed with fluorine-containing polyacrylate, acrylic resin, active monomer, photoinitiator and auxiliary agent, stirred and dispersed evenly, and ground to a fineness of less than 1 μm to obtain the hot-baking selective ink.

[0047] Example 2

[0048] A heat-baking selective ink comprising the following components in parts by weight:

[0049]

[0050] The preparation method of the hot-baking selected ink comprises the following steps:

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

[0052] S2. Using anhydrous ethanol as solvent, add KH550 and stir at 60°C for 3 hours, then add boron nitride and react for 3 hours (KH550:boron nitride=1:5, m / m), filter, wash, and dry to obtain an intermediate product;

[0053] Then, the intermediate product and polypropylene glycol diglycidyl ether in a mass ratio of 1:2 were mixed, reacted at 80° C. for 1 hour, filtered, washed, and dried to obtain modified boron nitride;

[0054] S3. According to the above-mentioned mass fractions, the modified boron nitride is mixed with fluorine-containing polyacrylate, acrylic resin, active monomer, photoinitiator and auxiliary agent, stirred and dispersed evenly, and ground to a fineness of less than 1 μm to obtain the hot-baking selective ink.

[0055] Example 3

[0056] A heat-baking selective ink comprising the following components in parts by weight:

[0057]

[0058] The preparation method of the hot-baking selected ink comprises the following steps:

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

[0060] S2. Using anhydrous ethanol as solvent, add KH550 and stir at 60°C for 3 hours, then add boron nitride and react for 3 hours (KH550:boron nitride=1:5, m / m), filter, wash, and dry to obtain an intermediate product;

[0061] Then, the intermediate product and polypropylene glycol diglycidyl ether in a mass ratio of 1:2 were mixed, reacted at 80° C. for 1 hour, filtered, washed, and dried to obtain modified boron nitride;

[0062] S3. According to the above-mentioned mass fractions, the modified boron nitride is mixed with fluorine-containing polyacrylate, acrylic resin, active monomer, photoinitiator and auxiliary agent, stirred and dispersed evenly, and ground to a fineness of less than 1 μm to obtain the hot-baking selective ink.

[0063] Comparative Example 1

[0064] A heat-baking selective ink. The difference between this comparative example and Example 1 is that the fluorinated polyacrylate is replaced by an acrylic resin of equal mass. The other ingredients and preparation method are the same as those in Example 1.

[0065] Comparative Example 2

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

[0067] Comparative Example 3

[0068] A hot-baking 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 the other ingredients and preparation method are the same as those in Example 1.

[0069] Test Case

[0070] The performance of the hot-baking selective inks prepared in Examples 1-3 and Comparative Examples 1-3 was tested.

[0071] The test method is as follows:

[0072] The hot-baked selective inks prepared in the examples and comparative examples were applied to the PCB boards respectively and photocured for 0.5 h (wavelength 395 nm, intensity 25.0 mW / cm 2The film was then cured at 150°C for 1 hour to form a 0.5 mm thick film.

[0073] Adhesion: Use a needle to make an X-shape on the film. Then, apply cellophane tape to the cuts and pull. Evaluate based on the following criteria:

[0074] Qualified: not torn off or a small amount torn off;

[0075] Unqualified: A lot of tearing off.

[0076] Bending resistance: Bend the film 180° with the ink film on the outside and evaluate based on the following criteria:

[0077] Qualified: No cracks on the film;

[0078] Unqualified: There are cracks on the film.

[0079] Heat resistance: Thermal shock performance test is conducted according to the method in IPC-SM-840E. The judgment criteria are as follows:

[0080] Qualified: no bubbles or cracks;

[0081] Unqualified: bubbles and cracks appear.

[0082] Acid / Alkali Resistance: Immerse the PCB coated with ink in a 10% sulfuric acid solution or a 10% sodium hydroxide solution at 20°C for 10 minutes. Remove the PCB and evaluate the coating's condition and adhesion. The criteria are as follows:

[0083] Pass: No change or slight change was found;

[0084] Unqualified: There is swelling or shedding on the coating film.

[0085] Film removal: Soak the sample in 5% sodium hydroxide solution at 50°C for 5 minutes. The judgment criteria are as follows:

[0086] Qualified: Completely stripped;

[0087] Unqualified: The film cannot be removed.

[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-cured selective inks prepared in Examples 1-3 of the present invention have a smooth appearance and excellent adhesion, mechanical strength, corrosion resistance, and stability. However, the substitution of fluorinated polyacrylate in Comparative Example 1 reduced the ink's acid and alkali resistance and stability, while the substitution of modified boron nitride in Comparative Examples 2-3 resulted in varying degrees of reduction in component compatibility, crosslinking, and toughness, impacting multiple product properties and resulting in suboptimal overall performance. In summary, the heat-cured selective inks of the present invention address the shortcomings of the prior art and have promising application prospects.

[0093] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0094] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods 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 mass: in, 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; The acrylic resin is a carboxyl-containing acrylic resin; The silane coupling agent is an aminosilane coupling agent.

2. 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.

3. 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, defoaming agent, dispersant, emulsifier, antioxidant, toughening agent and curing agent.

4. The method for preparing the hot-baking selective ink according to any one of claims 1 to 3, characterized in that: The preparation method of 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. Mix the modified boron nitride with fluorine-containing polyacrylate, acrylic resin, active monomer, photoinitiator and auxiliary agent, stir and disperse them evenly, grind and filter them to obtain the hot-baking selected ink.

5. The method for preparing the hot-baking selective ink according to claim 4, characterized in that: In step S1, the temperature of the heating and stirring reaction is 60-100°C.

6. The method for preparing the hot-baking selective ink according to claim 4, 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).

7. The method for preparing the hot-baking selective ink according to claim 4, characterized in that: In step S2, the temperature of the heating and stirring reaction is 30-100°C.

8. The method for preparing the hot-baking selective ink according to claim 4, characterized in that: The mass ratio of the boron nitride to polypropylene glycol diglycidyl ether is 1:(0.5-3).

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