CN103147075A - Novel water-soluble plated-copper protective agent and preparation method thereof - Google Patents

Abstract

The invention relates to a novel water-soluble protective agent for copper plating and a preparation method thereof. Using water as a solvent, the solute rare earth salt and the organic corrosion inhibitor form a rare earth complex skeleton on the copper-plated surface, and the surface organic corrosion inhibitor combines with the rare earth complex skeleton on the copper-plated surface to form a self-assembled film. The outside of the assembled film layer is covered with a layer of organic polymer film through physical adsorption. In this way, the three-dimensional film structure of the copper-plated surface is formed, which effectively prevents the harmful gas in the air from corroding the copper-plated surface, improves the salt spray resistance and anti-tarnish performance of the copper-plated surface, and the non-polar molecular groups at the end of the self-assembled film It can significantly improve the lubricity of the copper-plated surface and reduce the insertion force without affecting its electrical conductivity and soldering performance.

Description

Novel water-soluble copper plating protective agent and preparation method thereof

technical field

The invention relates to a copper-plated surface protectant and a preparation method thereof. The surface protectant is suitable for a filter in the communication industry or a protectant for the copper-plated surface of a printed circuit board.

Background technique

The cover plates, cavities and connectors of communication modules widely used in the communication industry are mostly made by silver plating. As the international silver price continues to rise, the traditional silver plating process is being transformed into a relatively low-cost copper plating process. However, because the reactivity of metallic copper is much higher than that of silver, it is easily mixed with moisture, SO ₂ , H in the air. ₂ S, NO ₂ and other media will generate corrosion products or oxides, which will increase the contact resistance of communication devices, cause electrical signals to be unstable or interrupted, and even cause accidents. Therefore, the protection problem of copper plating is an important difficult problem that people are trying to overcome.

At present, to solve the problem of copper plating protection, two methods are mainly used:

The first method is to enhance the sealing of micropores on the copper-plated surface. Using organic solvent-based protective agent, taking advantage of the good solubility of organic solvents, the corrosion inhibitor dissolved in it is brought into the pores of the copper plating surface. After the organic solvent volatilizes, the corrosion inhibitor is attached to the pores and has a good effect on copper plating. The surface forms an effective seal - to isolate harmful gas components in the atmosphere, so as to achieve the purpose of protection. However, the organic solvent used in this method is a halogen-containing volatile liquid, which has been banned because of its destructive effect on the atmospheric ozone layer. From January 1, 2011, all countries that signed the "Montreal Treaty" (my country Belonging to one of the signatories), the production and use of such organic solvents are prohibited.

The second approach focuses on surface passivation. A single passivation of imidazole compounds is used to form a uniform and dense passivation oxide film on the surface of copper plating to isolate harmful gas components in the atmosphere and achieve the purpose of protection. Although this method can make the passivation oxide film formed on the copper-plated surface uniform and dense, it greatly increases the contact resistance of the electrical contact surface due to its thick film layer, and the salt spray resistance of the surface of the copper-plated product is poor. Therefore, it is not suitable for some electronic components with high electrical performance requirements.

Contents of the invention

The purpose of the present invention is to overcome the existing difficulties in copper plating protection and provide an environmentally friendly and efficient copper plating protective agent and a preparation method thereof.

The present invention is achieved like this:

Using water as solvent, rare earth salt, organic corrosion inhibitor, organic macromolecule and surfactant as solute, the distribution ratio of each component is:

a. The mass ratio of the rare earth salt is 0.5-2%;

b. The mass ratio of organic corrosion inhibitor is 20-25%;

c. The mass ratio of organic polymers is 10-20%;

d. The mass ratio of surfactant is 15-20%;

e. The balance is water.

The rare earth salt refers to a compound of two lanthanide metal salts;

The organic corrosion inhibitor refers to a compound of at least two substances among nitrogen azoles, imidazoles, aryl imidazoles, and organic amine compounds. The compounding ratio of azoles and imidazoles is 1:1, the compounding ratio of nitrogenous azoles and organic amines is 1:2, and the compounding ratio of imidazoles and organic amines is 1:2;

The organic amine compound is an equal proportion mixture of one or two or three of RNH ₂ , R ₂ NH and R ₃ N, and the molecular formula of R is C _n H _2n+1 , where n≥6;

The organic polymer refers to polyethylene wax;

The surfactant refers to an alkyl ether surfactant;

The water refers to industrial deionized water.

The preparation method of water-soluble protective agent for copper plating of the present invention is carried out according to the following steps:

a. Add 40-60% of the calculated amount of deionized water into the reactor and heat it to 45-50°C;

b. Accurately weigh the calculated amount of rare earth salt, add deionized water at 45-50°C, stir until dissolved, and obtain a colorless and transparent solution A;

c. Accurately weigh the calculated amount of organic corrosion inhibitor, add it to the reaction solution, and stir until dissolved at 45-50°C to obtain a light yellow solution B;

d. Accurately weigh the calculated amount of surfactant (also known as "OP10"), and heat it at 40-45°C until completely dissolved to obtain a dark yellow transparent solution C;

e. Pour solution C into solution B while it is hot, and stir at 40-45°C for 15 minutes to obtain light yellow emulsion D;

f. Accurately weigh the calculated amount of organic polymer, add solution D to obtain a light yellow viscous liquid, stir at 40-45°C for 45 minutes, add the remaining amount of deionized water to it, and continue stirring until the viscous liquid is fine Evenly, the product is obtained.

The using method of this water-soluble copper plating protective agent, carries out according to the following steps:

a. Heat the protective agent stock solution in a water bath to 40-45°C to make the protective agent stock solution a uniform viscous fluid solution;

b. Heat the deionized water to 40-45°C, pour it into the heated protective agent stock solution, and stir until the protective agent stock solution is diluted into a milky white working solution with a concentration of 10-20%;

c. Soak the clean workpiece to be protected in the protective agent working solution at 40-45°C for 90-180s;

d. Wash the workpiece with protective agent in deionized water at 35-40°C for 2-3 times, and then dry the cleaning water in the blind hole of the workpiece;

e. Use compressed air to blow off the cleaning water on the blind hole and surface of the workpiece;

f. Bake the cleaned and dried workpiece in an oven at 80-120°C for 30-45 minutes;

g.. Place the dried workpiece at room temperature for 2 to 4 hours.

The mechanism of action of the protective agent is:

1. Rare earth ions can form a series of complexes with inorganic and organic ligands in aqueous solution. Since these rare earth ions have a large volume, from the perspective of the space requirements for ligand arrangement, the complexes will have a higher coordination number. The biggest difference between rare earth complexes and complexes of d-block transition elements such as Zn and Cr is that rare earth ions can form complexes with high coordination numbers. Coordination numbers 4 and 6 are the characteristic coordination numbers of d-block transition elements, but the coordination numbers of rare earth elements are often greater than 6, with 7, 8, 9, 10, and even as high as 12. However, there are a large amount of nitrogen-containing ligands (such as BTA) in the protective agent solution, and these ligands have a strong coordination ability with rare earth ions, forming complexes of BTA and rare earth ions in the solution, and BTA can also be combined with copper Complexation, forming a polymeric Cu(I)BTA complex on the surface. After adding rare earth ions, the complexes of BTA and rare earth ions can not only be adsorbed on the copper surface, but also complexed with copper, changing the structure of the film, covering the copper plating surface with a layer of complex skeleton, reaching the first Heavy protection purposes.

2. After the rare earth complex covers the copper-plated surface with a complex skeleton, due to the large volume of the rare-earth complex, there will still be a small amount of copper atoms on the copper-plated surface that cannot form a protective film with the rare-earth complex. In this case, we use a relatively small organic corrosion inhibitor to complex the copper atoms or ions in the gaps through self-assembly technology to achieve the second protection purpose.

3. After double protection, a layer of complex protective film has been formed on the copper-plated surface. At this time, an organic polymer polyethylene wax with surface modification is used to form a thin film on the outermost layer. This film is electrostatically adsorbed, physically Adsorption forms a weak force with the copper-plated surface to achieve the third protection purpose.

4. Effect of surfactant: The aqueous solution state of organic corrosion inhibitor and rare earth salt is very unstable, and the solution is easy to stratify. Use surfactant OP10 to promote the dissolution of organic corrosion inhibitor, and then use polyethylene wax to adjust the solution state. Make the state of protective agent concentrate and working fluid uniform and stable, and the coating appearance is bright and free of flow marks.

The advantages of the present invention are:

1. Significantly improve the protection ability of copper-plated surface: It is proved by GB/T2423.17 neutral salt spray test that the salt spray test of copper-plated modules treated with this protective agent can reach 24h, which is significantly better than unprotected copper-plated modules. Greatly improved salt spray resistance; in sulfur dioxide, hydrogen sulfide and natural exposure tests, it also has excellent anti-discoloration and anti-corrosion effects.

2. Stable electrical performance: The copper-plated module is under lubrication protection, which reduces the adverse effects of operation and environment on it, ensures the conductivity of the communication module, and does not affect its welding performance.

3. Safety and environmental protection: The present invention uses deionized water as a solvent, does not contain heavy metals such as chromium, mercury, lead, cadmium, polybrominated biphenyls, and polybrominated diphenyl ethers.

The invention abandons the organic solvent of the traditional solvent-based protective agent, uses water as the solvent, and uses surface self-assembly technology to form a firm three-dimensional film structure on the copper-plated surface to isolate harmful components in the air from the copper-plated surface , so as to achieve environmentally friendly and efficient protection of the copper-plated surface, improve the salt spray resistance and anti-discoloration performance of the copper-plated communication module, and at the same time ensure its electrical performance and welding performance. The invention has the advantages of simple production process, convenient use, environmental friendliness, reduced cost and saved social resources.

Description of drawings

The schematic diagram of the mechanism of action of Fig. 1 protective agent of the present invention

Detailed ways:

Describe three embodiments below, the present invention will be further described

Fig. 1 has shown the protective mechanism of protective agent of the present invention:

1. Rare earth ions form complexes of rare earth ions in aqueous solution, and BTA can also complex with copper to form polymeric Cu(I)BTA complexes on the surface. After addition of rare earth ions, BTA is formed. The complex of rare earth ions can not only adsorb on the copper surface, but also complex with copper, change the structure of the film, and cover the copper-plated surface with a layer of complex skeleton to achieve the first protection purpose.

2. After the rare earth complex covers the copper-plated surface with a complex skeleton, due to the large volume of the rare-earth complex, there will still be a small amount of copper atoms on the copper-plated surface that cannot form a protective film with the rare-earth complex. In this case, a relatively small organic corrosion inhibitor is used to complex the copper atoms or ions in the gaps through self-assembly technology to achieve the second protection purpose.

3. After double protection, a layer of complex protective film has been formed on the copper-plated surface. At this time, an organic polymer polyethylene wax with surface modification is used to form a thin film on the outermost layer. This film is electrostatically adsorbed, physically Adsorption forms a weak force with the copper-plated surface to achieve the third protection purpose.

Example 1 Prepare 1000 g of protective agent.

Dosing of each component according to the following mass ratio: rare earth salt lanthanum chloride 6g, neodymium chloride 6g; organic corrosion inhibitor benzotriazole 75g, imidazole 75g, polyethylene wax 100g, surfactant OP10150g, the rest is deionized 588g of water.

The preparation process of this embodiment is:

1. Add 40% deionized water to the reactor and heat to 45-50°C;

2. Accurately weigh 6g of the rare earth salts of lanthanum chloride and neodymium chloride, add the above-mentioned deionized water, stir until dissolved, and obtain a colorless and transparent solution A;

3. Accurately weigh 75g of the organic corrosion inhibitor benzotriazole and add it to the reaction solution, and stir until dissolved at 45-50°C to obtain a light yellow solution B;

4. Accurately weigh 75g of organic corrosion inhibitor imidazole and 150g of surfactant OP10, mix and heat at 40-45°C until the mixture is completely dissolved to obtain dark yellow transparent solution C;

5. Pour solution C into solution B while it is hot, and stir at 40-45°C for 15 minutes to obtain light yellow emulsion D;

6. Accurately weigh 100g of organic high-molecular polyethylene wax, add solution D to obtain light yellow viscous liquid, stir at 40-45°C for 45min, add the remaining amount of deionized water to it to 1000g, and continue stirring until viscous The viscous liquid is fine and uniform, and the product is obtained.

7. Filling.

The using method of the protective agent for copper plating of the present embodiment is carried out according to the following steps:

a. Heat the protective agent stock solution in a water bath to 40-45°C to make the protective agent stock solution a uniform viscous fluid solution;

b. Heat the deionized water to 40-45°C, pour it into the heated protective agent stock solution, and stir until the protective agent stock solution is diluted into a milky white working solution with a concentration of 10-20%;

c. Soak the clean workpiece to be protected in the protective agent working solution at 40-45°C for 90-180s;

d. Wash the workpiece with protective agent in deionized water at 35-40°C for 2-3 times, and then dry the cleaning water in the blind hole of the workpiece;

e. Use compressed air to blow off the cleaning water on the blind hole and surface of the workpiece;

f. Bake the cleaned and dried workpiece in an oven at 80-120°C for 30-45 minutes;

g.. Place the dried workpiece at room temperature for 2 to 4 hours, pack, store and transport.

Example 2 Prepare 1000 g of protective agent.

Dosing of each component according to the following mass ratio: rare earth salt yttrium chloride 2.5g, neodymium chloride 2.5g; organic corrosion inhibitor benzotriazole 75g, dodecylamine 150g, polyethylene wax 150g, surfactant OP10 200g, the rest is 420g deionized water.

The preparation process of this embodiment is:

1. Add 60% deionized water to the reactor and heat to 45-50°C;

2. Accurately weigh 2.5g each of the rare earth salts of yttrium chloride and neodymium chloride, add 45-50°C deionized water, stir until dissolved, and obtain a colorless and transparent solution A;

3. Accurately weigh 75g of the organic corrosion inhibitor benzotriazole and add it to the reaction solution, and stir until dissolved at 45-50°C to obtain a light yellow solution B;

4. Accurately weigh 150g of organic corrosion inhibitor dodecylamine and 10200g of surfactant OP, mix and heat at 40-45°C until the mixture is completely dissolved to obtain dark yellow transparent solution C;

5. Pour solution C into solution B while it is hot, and stir at 40-45°C for 15 minutes to obtain light yellow emulsion D;

6. Accurately weigh 150g of organic high-molecular polyethylene wax, add solution D to obtain light yellow viscous liquid, stir at 40-45°C for 45 minutes, add the remaining amount of deionized water to it, and make it up to 1000g, and continue stirring until viscous The viscous liquid is fine and uniform, and the product is obtained.

7. Filling.

The usage method of this embodiment is the same as that of Embodiment 1.

Example 3 Prepare 1000 g of protective agent.

Dosing of each component according to the following proportions: rare earth salt yttrium chloride 10g, lanthanum chloride 10g; organic corrosion inhibitor benzotriazole 50g, phenylimidazole 50g, dodecylamine 100g, polyethylene wax 200g, surface The active agent OP10 is 180g, and the rest is 400g of deionized water.

The preparation process of this embodiment is:

1. Add 50% deionized water to the reactor and heat to 45-50°C;

2. Accurately weigh 5g each of the rare earth salts of yttrium chloride and lanthanum chloride, add 45-50°C deionized water, stir until dissolved, and obtain a colorless and transparent solution A;

3. Accurately weigh 50 g of the organic corrosion inhibitor benzotriazole and add it to the reaction solution, and stir until dissolved at 45-50°C to obtain a light yellow solution B;

4. Accurately weigh 50g of organic corrosion inhibitor phenylimidazole, 100g of dodecylamine, and 200g of surfactant OP10, mix and heat at 40-45°C until the mixture is completely dissolved to obtain dark yellow transparent solution C;

5. Pour solution C into solution B while it is hot, and stir at 40-45°C for 15 minutes to obtain light yellow emulsion D;

6. Accurately weigh 200g of organic high-molecular polyethylene wax, add solution D to obtain light yellow viscous liquid, stir at 40-45°C for 45 minutes, add the remaining amount of deionized water to it, and make it up to 1000g, and continue stirring until viscous The viscous liquid is fine and uniform, and the product is obtained.

7. Filling.

The usage method of this embodiment is the same as that of Embodiment 1.

Claims (4)

1. new type water-solubility copper facing protective material, it is characterized in that: with water as solvent, rare-earth salts, organic inhibitor, organic polymer and tensio-active agent are solute, and each component proportion is:

A. the shared mass ratio of rare-earth salts is 0.5～2%;

B. the shared mass ratio of organic inhibitor is 20～25%;

C. the shared mass ratio of organic polymer is 10～20%;

D. the shared mass ratio of tensio-active agent is 15～20%;

E. surplus is water;

Described rare-earth salts refers to the composite of two kinds of lanthanide metal salts;

Described organic inhibitor refers at least two kinds of components composite in nitrogen azole, imidazoles, arylimidazoles, organic amine compound; This organic amine compound is RNH ₂, R ₂NH, R ₃One or both in N, the equal proportion mixture of three kinds, the R molecular formula is C _nH _2n+1, n 〉=6 wherein;

Described organic polymer refers to polyethylene wax;

Described tensio-active agent refers to the alkyl ether tensio-active agent;

Described water refers to industrial deionized water.

2. new type water-solubility copper facing protective material according to claim 1; it is characterized in that; the composite weight proportion of several organic inhibitions is: when agent nitrogen azole and imidazoles are composite, proportioning is 1: 1, and when nitrogen azole and organic amine are composite, proportioning is 1: 2, and when imidazoles and organic amine are composite, proportioning is 1: 2

3. the protectant preparation method of new type water-solubility copper facing according to claim 1, is characterized in that, carries out according to following step:

A. add the deionized water of 40～60% calculated amount in the reactor, be heated to 45～50 ℃;

B. accurately take the rare-earth salts of calculated amount, add above-mentioned deionized water, be stirred to dissolving, get colourless transparent solution A;

C. accurately take the organic inhibitor of calculated amount, add reaction soln, be stirred to dissolving under 45～50 ℃, get yellow solution B;

D. accurately take the tensio-active agent of calculated amount, be heated to dissolving fully under 40～45 ℃, get deep yellow clear solution C;

E. solution C is poured in solution B while hot, stirred 15min under 40～45 ℃, get faint yellow emulsion D;

F. accurately take the organic polymer of calculated amount, add solution D, get faint yellow viscous fluid, after stirring 45min under 40～45 ℃, add wherein surplus deionized water constant volume, continue to be stirred to viscous fluid evenly fine and smooth, namely get product.

4. the protectant using method of new type water-solubility copper facing according to claim 1, is characterized in that, carries out according to following step:

A. the water-bath of protective material stoste is heated to 40～45 ℃, makes protective material stoste be the solution of even thickness mobility;

B. deionized water is heated to pour into after 40～45 ℃ in the protective material stoste that heats, being stirred to protective material stoste, to be diluted as concentration be 10～20% oyster white working fluid;

The workpiece to be protected that c. will clean soaks 90～180s in 40～45 ℃ of protective material working fluids;

D. the workpiece that will do the overprotection agent cleans 2～3 times in 35～40 ℃ of deionized waters, then controls the rinse water in dried workpiece blind hole;

E. blow away the rinse water on workpiece blind hole and surface with pressurized air;

F. the workpiece after cleaning being dried up toasts 30～45min in 80～120 ℃ of baking ovens;

G.. the workpiece after drying is placed 2～4h in room temperature, gets final product.

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