CN115852679A - Method for realizing copper-nickel double-layer chemical plating by silk fabric iron activation method - Google Patents

Abstract

Using silk fabric as the base material, first put the fabric into the prepared polydopamine solution and let it stand for 24 hours, then wash and dry the fabric, and then soak it in 35-45g/L ferrous chloride solution for 5 minutes , to chelate and adsorb iron ions. During this process, ultrasonic waves are used to oscillate for 2 minutes, and then placed in an alkaline solution of 4-5 g/L potassium borohydride to reduce iron ions on the fabric for 5-15 minutes. Catalytically active elemental iron and electroless copper plating, the copper-plated fabric also adopts this method for electroless nickel plating, and finally successfully realized copper-nickel double-layer electroless plating on silk fabrics. This process is environmentally friendly and economical. The metallized fabric coating is firmly bonded, and its electromagnetic shielding performance can reach 90dB in the frequency range of 0.5-18GHZ, which meets the requirements of military industry.

Description

Copper-nickel double-layer electroless plating by iron activation method on silk fabric

technical field

The invention relates to a pretreatment activation process for electroless copper plating and nickel plating on silk fabrics, and belongs to the field of electroless plating.

Background technique

The surface of the metalized fabric can have electromagnetic shielding performance to resist the harm caused by electromagnetic waves to the human body. For example, personnel working in special environments and pregnant women need to wear this kind of fabric with electromagnetic shielding performance. As a high-performance textile material, silk has Skin-friendly, soft and other characteristics. Nickel has magnetism, and electromagnetic waves generate magnetic loss through the nickel layer, while metallic copper has good conductivity. After copper-nickel double-layer electroless plating, the surface of the fabric can have a metal layer with a gradient structure to achieve good electromagnetic shielding performance. At present, There are few studies on double-layer metallization on the surface of silk fabrics.

Electroless plating is an excellent surface metallization treatment technology, but most of the activation methods used in electroless copper plating and nickel plating use precious metals, such as palladium activation or silver activation. This activation method is costly and harmful to the environment. Research on the activation method of electroless nickel plating by promoting the reaction of nickel acetate and sodium hypophosphite to form nickel element by high temperature to form a self-catalytic activation center, but this activation method is not suitable for materials that are not resistant to high temperatures such as fabrics. Cobalt ion obtains the activation method of elemental cobalt, but cobalt is still a kind of heavy metal that can have adverse impact on the environment. Chinese patent CN101096756A has announced a kind of iron activation method of electroless nickel plating, and ferric iron is reduced by sodium hypophosphite , but in the experiment, it was found that when this method is applied to the fabric, the activation effect is not ideal, the surface of the fabric cannot be completely plated, and the bonding force of the coating is poor.

Contents of the invention

The invention provides a new process for pretreatment and activation of electroless copper plating and nickel plating on silk fabrics. The method saves cost, has no harm to the environment, does not require high temperature conditions and has good bonding force.

In order to solve the above problems, the activating solution used in the present invention consists of: 35-45g/L ferrous chloride solution, 4-5g/L potassium borohydride solution and 0.8-1.5g/L potassium hydroxide. First, put the polydopamine-modified silk fabric into the ferrous chloride solution to chelate the iron ions to absorb more iron ions, and with the action of ultrasonic vibration, the iron ions infiltrate into the pores of the fabric to make the adsorption even , ultrasonic oscillation time 2min, power 80w, and then use alkaline potassium borohydride solution to reduce iron ions on the surface of the fabric to obtain iron element with activation ability. The activation time of this process is 5-15min, the activation temperature is 30-40℃, and then chemical Copper-nickel plating realizes double-layer metallization on the silk fabric, and the surface coating of the silk fabric modified by polydopamine does not fall off or peel after repeated bending, showing good bonding force.

Copper-nickel double-layer electroless plating is realized by the iron activation method of silk fabrics, including the following steps: degreasing→water washing→glue removal→water washing→roughening→water washing→polydopamine modification→water washing→iron activation→water washing→electroless copper plating→water washing→ Iron activation→water washing→electroless nickel plating→water washing→drying.

The described silk fabric iron activation method realizes copper-nickel double-layer electroless plating, and its degreasing step adopts absolute ethanol, and what degumming adopts is NaOH 4g/L, at 50 ℃ temperature, time is 15min, also can adopt carbonic acid Sodium 20g/L at 65°C for 30min to remove gum.

The described silk fabric iron activation method realizes copper-nickel double-layer electroless plating, and its roughening process is hydrochloric acid 30g/L, acetic acid 50g/L, dissolves in distilled water and the mixed solution that ethanol volume ratio is 1:1, 45 ℃, 1.5h.

The silk fabric iron activation method realizes copper-nickel double-layer electroless plating, and the modification process of polydopamine is as follows: first weigh Tris (trishydroxymethylaminomethane) powder and add it to deionized water and prepare 2.8g/L Solution, and add polydopamine hydrochloride powder at a concentration of 4g/L, then adjust the pH to 8.5 with hydrochloric acid, soak the roughened fabric in the solution, leave it at room temperature for 24h, wash it with deionized water, and then dry it in an oven Dry at 45°C.

The silk fabric iron activation method realizes copper-nickel double-layer electroless plating. The copper plating formula and process conditions used in the activation method are CuSO ₄ ∙ 5H ₂ O 16 g/L, NaKC ₄ H ₄ O ₆ 14g/L, EDTA-2Na 20g/L, NaOH 15g/L, HCHO 12ml/L, trace amount of stabilizer, temperature 30~40℃, time 45min.

The described silk fabric iron activation method realizes copper-nickel double-layer electroless plating, and the nickel plating formula and process condition that this activation method adopts are: NiSO ₄ ∙ 6H ₂ O 28g/L, H ₂ NCH ₂ COOH (glycine) 8g/ L, HAC-NaAC (acetic acid-sodium acetate) 15g/L, NaH ₂ PO ₂ ∙H ₂ O 30g/L, trace amount of stabilizer, temperature 80°C, time 45min.

Among them, the water washing step is to wash away the organic solvent and residual impurities on the surface of the fabric, but the activated fabric should be washed properly to avoid the detachment of a large amount of iron on the surface of the fabric caused by excessive washing, and the purpose of roughening is to make pits on the surface of the fabric , to provide the growth carrier for the deposition of follow-up activated particle attachment and coating, in the present invention, do not limit the specific addition amount of ferrous chloride, potassium borohydride and potassium hydroxide, also do not limit specific activation time and activation temperature, but It should be controlled within the range mentioned above.

The invention has the following beneficial effects: the invention uses polydopamine to modify the surface of the fabric, which not only makes the surface of the substrate rougher, but also can chelate and adsorb iron ions, so that the uniformity and binding force of the silk fabric coating can be improved. Improvement, the reduction effect of potassium borohydride on iron ions is good, and the addition of potassium hydroxide improves the stability of potassium borohydride solution and is not easy to fail. Moreover, substrates such as fabrics require a large-area electroless plating process to As an activation method, iron is obviously superior to other activation methods in terms of economy, and is environmentally friendly and pollution-free.

Description of drawings

Figure 1 is the original SEM image of silk fabric.

Figure 2 is the SEM image of silk fabric after activation.

Figure 3 is the SEM image of the silk fabric after electroless copper plating.

Figure 4 is a SEM image of silk fabric after electroless copper-nickel plating.

Figure 5 is the EDS diagram of silk fabric after activation.

Figure 6 is an EDS image of silk fabric after electroless copper-nickel plating.

Figure 7 is a diagram of the electromagnetic shielding performance of silk fabrics before and after electroless plating.

Detailed ways

The present invention makes the following descriptions for specific operations and implementations.

Example 1: The technological process of electroless copper-nickel double-layer metal plating by iron activation method on silk fabrics is: degreasing (absolute ethanol)→water washing→degumming (sodium hydroxide 4g/L, 50°C, 15min)→water washing→ Coarsening (dissolve hydrochloric acid 30g/L, acetic acid 50g/L in a mixed solution of distilled water and ethanol with a volume ratio of 1:1, 45°C, 1.5h)→water washing→polydopamine modification→water washing→iron activation→water washing→chemical Copper plating→water washing→iron activation→water washing→electroless nickel plating→water washing→drying, the treatment process of polydopamine modification is as follows: Weigh Tris (trishydroxymethylaminomethane) powder into deionized water and prepare 2.8g/ L solution, then weigh 4g of polydopamine hydrochloride powder and add it to the solution, and adjust the pH to 8.5 with hydrochloric acid, soak the roughened fabric in the solution, and wash it with deionized water after standing at room temperature for 24h , and then dried in an oven at 45°C.

The specific operation method for the iron activation of silk fabrics is as follows: First, the silk fabrics modified by polydopamine are picked up with tweezers and soaked in a beaker filled with 35-45g/L ferrous chloride solution for 5 minutes, and ultrasonic waves are applied during the process. Auxiliary vibration for 2 minutes, in order to fully infiltrate the iron ions into the pores of the silk fabric, the ultrasonic power is 80w, then take out the fabric from the solution and place it in a beaker filled with alkaline potassium borohydride solution for reduction and obtain a catalytically active For simple iron, the activation time of this process is 5-15 minutes, and the activation temperature is 30-40°C. The preparation method of alkaline potassium borohydride is: first add 0.8-1.5g potassium hydroxide to a beaker, and then add deionized water to The solution was nearly 1L and stirred evenly, and finally 4-5g of potassium borohydride was added and stirred evenly again.

Copper plating formula and process conditions are CuSO ₄ ∙ 5H ₂ O 16g/L, NaKC ₄ H ₄ O ₆ 14g/L, EDTA-2Na 20g/L, NaOH 15g/L, HCHO 12ml/L, trace amount of stabilizer, temperature 30~40℃, time 45min, the specific operation is: first mix NaKC ₄ H ₄ O ₆ 14g/L, EDTA-2Na 20g/L two solutions to form a compound complexing agent, then add CuSO ₄ ∙ 5H ₂ O 16g in turn /L, NaOH 15g/L solution, then add reducing agent HCHO 12ml/L and stir evenly, finally add stabilizer, place the activated silk fabric in the solution for electroless copper plating.

Nickel plating formula and process conditions are NiSO ₄ ∙6H ₂ O 28g/L, H ₂ NCH ₂ COOH (glycine) 8g/L, HAC-NaAC (acetic acid-sodium acetate) 15g/L, NaH ₂ PO ₂ ∙H ₂ O 30g/L, trace amount of stabilizer, temperature 80°C, time 45min, the specific operation is: first complex the _H2NCH2COOH ( _glycine ) 8g/L, HAC-NaAC (acetic acid-sodium acetate) 15g/L and then add NiSO ₄ ∙ 6H ₂ O 28g/L, NaH ₂ PO ₂ ∙H ₂ O 30g/L and stabilizer in sequence. During the process, each reagent added should be stirred evenly, and the copper-plated silk After the fabric is washed and dried, the iron activation process is carried out, and then it is put into the nickel plating solution for electroless plating.

Use scanning electron microscope to observe the surface morphology of the main process stages of silk fabric electroless plating, as shown in Figure 1, Figure 2, Figure 3, and Figure 4, the surface coating of the fabric is uniform and dense after electroless copper-nickel plating, and analyzed by energy spectrometer The surface element composition of silk fabric before and after electroless plating is shown in Figure 5 and Figure 6, and Figure 5 shows that the surface of the activated fabric contains more iron elements, and it can be seen from Figure 2 that iron active particles are attached to the surface of the fabric. Figure 4 and Figure 6 further prove that the activation method has successfully realized copper-nickel double-layer electroless plating on silk fabrics. From Figure 7, the original silk fabric does not possess electromagnetic shielding performance. In the 18GHZ broadband range, its electromagnetic shielding performance can reach 90 decibels, which meets the technical requirements of military industry.

Taking the copper plating layer deposition rate as the evaluation index, under the conditions of immersion time of 5 minutes, ultrasonic assisted oscillation time of 2 minutes, power of 80w, and potassium hydroxide concentration of 1g/L, the concentration of ferrous chloride (35-45g/L) , Potassium borohydride concentration (4-5g/L), activation time (5-15min), activation temperature (30-40°C) and four factors are carried out by orthogonal experiments in Examples 2-10.

Embodiment 2: Electroless copper-nickel plating by iron activation method on the surface of silk fabrics, the activation factors are: ferrous chloride 35g/L, potassium borohydride 4g/L, activation time 5min, activation temperature 25/°C, all the other conditions are the same as in the embodiment 1. The resulting deposition rate was 6.31 μm/h.

Embodiment 3: Electroless copper-nickel plating by iron activation method on the surface of silk fabrics, activation factors are: ferrous chloride 35g/L, potassium borohydride 4.5g/L, activation time 10min, activation temperature 30/°C, and other conditions are the same as implementation In Example 1, a deposition rate of 6.65 μm/h was obtained.

Embodiment 4: Iron activation method electroless copper-nickel plating on the surface of silk fabrics, its activation factors are: ferrous chloride 35g/L, potassium borohydride 5g/L, activation time 15min, activation temperature 35/°C, all the other conditions are implemented with In Example 1, a deposition rate of 6.63 μm/h was obtained.

Embodiment 5: Electroless copper-nickel plating by iron activation method on the surface of silk fabrics, the activation factors are: ferrous chloride 40g/L, potassium borohydride 4g/L, activation time 15min, activation temperature 30/°C, and other conditions are the same as implementation In Example 1, a deposition rate of 7.23 μm/h was obtained.

Embodiment 6: Iron activation method electroless copper-nickel plating on silk fabric surface, its activation factors are: ferrous chloride 40g/L, potassium borohydride 4.5g/L, activation time 5min, activation temperature 35/℃, all the other conditions are the same Example 1, the obtained deposition rate is 6.96 μm/h.

Embodiment 7: Electroless copper-nickel plating by iron activation method on the surface of silk fabrics, the activation factors are: ferrous chloride 40g/L, potassium borohydride 5g/L, activation time 10min, activation temperature 25/°C, and other conditions are the same as implementation In Example 1, a deposition rate of 7.21 μm/h was obtained.

Embodiment 8: Electroless copper-nickel plating by iron activation method on the surface of silk fabrics, the activation factors are: ferrous chloride 45g/L, potassium borohydride 4g/L, activation time 10min, activation temperature 35/°C, and other conditions are the same as implementation In Example 1, a deposition rate of 7.56 μm/h was obtained.

Embodiment 9: Electroless copper-nickel plating by iron activation method on the surface of silk fabrics, the activation factors are: ferrous chloride 45g/L, potassium borohydride 4.5g/L, activation time 15min, activation temperature 25/°C, and other conditions are the same Example 1, the obtained deposition rate is 7.13 μm/h.

Example 10: Electroless copper-nickel plating by iron activation method on the surface of silk fabrics, the activation factors are: ferrous chloride 45g/L, potassium borohydride 5g/L, activation time 5min, activation temperature 30/°C, and the rest of the conditions are the same as the implementation In Example 1, a deposition rate of 7.39 μm/h was obtained.

Known from the above examples: the deposition rate of Example 8 is 7.56 μm/h, which is a preferred example, that is, the formula and process conditions of the activation solution are: ferrous chloride 45g/L, potassium borohydride 4g/L, hydrogen The concentration of potassium oxide is 1g/L, the activation time is 10min, and the activation temperature is 35°C. The best embodiment of the present invention is not limited thereto. For those skilled in the art, all modifications and replacements made in the claims belong to the present invention. protection scope of the invention.

Claims (4)

1. Silk fabric iron activation method realizes copper-nickel double-layer electroless plating, it is characterized in that, this technique needs to carry out the modification of polydopamine earlier and realizes the chelation to iron ion, and the preparation process of its polydopamine solution is: take Tris ( Trishydroxymethylaminomethane) powder was added to deionized water to prepare a 2.8g/L solution, and polydopamine hydrochloride powder was added at a concentration of 4g/L, then the pH of the solution was adjusted to 8.5 with hydrochloric acid, and the roughened fabric was soaked In this solution, after standing at room temperature for 24 hours, it was cleaned with deionized water, and dried in an oven at 45° C., and then iron activation and electroless copper-nickel plating were performed. 2. The silk fabric iron activation method according to claim 1 realizes copper-nickel double-layer chemical plating, it is characterized in that, the prescription of described iron activation consists of: 35～45g/L ferrous chloride, 4～5g/L L of potassium borohydride, 0.8~1.5g/L potassium hydroxide, the process is: put the polydopamine-modified silk fabric in the ferrous chloride solution for 5 minutes, apply ultrasonic auxiliary vibration for 2 minutes in the process, and the ultrasonic power 80w, then take the fabric out of the solution and transfer it to an alkaline potassium borohydride solution made of 4~5g/L potassium borohydride and 0.8~1.5g/L potassium hydroxide, and reduce it at a temperature of 30~40℃ Iron ions are mixed for 5-15 minutes to obtain iron element with catalytic activity. 3. The silk fabric iron activation method according to claim 1 realizes copper-nickel double-layer electroless plating, characterized in that, the copper plating formula and process conditions used for the iron activation are: CuSO ₄ ∙ 5H ₂ O 16g/L , NaKC ₄ H ₄ O ₆ 14g/L, EDTA-2Na 20g/L, NaOH 15g/L, HCHO 12ml/L, trace amount of stabilizer, temperature 30~40℃, time 45min. 4. The iron activation method of silk fabric according to claim 1 realizes copper-nickel double-layer electroless plating, characterized in that, the nickel plating formula and process conditions used in the iron activation are: NiSO ₄ ∙ 6H ₂ O 28g/L , H ₂ NCH ₂ COOH (glycine) 8g/L, HAC-NaAC (acetic acid-sodium acetate) 15g/L, NaH ₂ PO ₂ ∙H ₂ O 30g/L, trace amount of stabilizer, temperature 80°C, time 45min.

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