PREVENTION OF UNWANTED PLATING ON RACK COATINGS FOR ELECTRODEPOSITION

Abstract

A support for supporting a component to be plated in a chromic acid-free plating process, the support having a contact surface comprising iodine-treated and/or bromine-treated plastic.

Claims

1. A support for supporting a component to be plated in a chromic acid-free plating process, the support having a contact surface comprising iodine-treated and/or bromine-treated plastic.

2. The support of claim 1, wherein the contact surface comprises iodine-treated plastic.

3. The support of claim 1, wherein the plastic comprises PVC, preferably PVC plastisol.

4. The support of claim 1, wherein the support comprises metal at least partially coated with the plastic.

5. A plating apparatus for use in a chromic acid-free plating process, the plating apparatus comprising a plating vessel having one or more supports for supporting a component to be plated, the one or more supports having a contact surface comprising iodine-treated and/or bromine-treated plastic.

6. A method of treating a support for supporting a component to be plated in a chromic acid-free plating process, the support having a contact surface comprising plastic, the method comprising: providing a support for supporting a component to be plated in a chromic acid-free plating process, the support having a contact surface comprising plastic; providing an aqueous solution comprising one or both of iodine and bromine; and contacting at least a portion of the plastic of the contact surface of the support with the aqueous solution.

7. The method of claim 6, wherein the aqueous solution comprises iodine.

8. The method of claim 7, wherein the aqueous solution comprises 0.005 to 0.1M iodine, preferably from 0.01 to 0.05 M iodine.

9. The method of claim 7, wherein the aqueous solution comprises iodide ions.

10. The method of claim 8, wherein the molar ratio of iodide ions to iodine is at least 1:1.

11. The method of claim 7, wherein the step of providing the aqueous solution comprises contacting iodide ions with an oxidizing agent in aqueous solution, the oxidising agent selected from iodate ions, persulfate ions, nitrate ions, hydrogen peroxide and combination of two or more thereof, preferably wherein the oxidizing agent comprises iodate ions.

12. The method of claim 6, wherein the support is contacted with the aqueous solution for at least 10 seconds, preferably at least 30 seconds, more preferably from 1 to 10 minutes, even more preferably from 1 to 5 minutes.

13. The method of claim 6, wherein the plastic of the contact surface of the support comprises PVC, preferably PVC plastisol.

14. The method of claim 6, wherein the plating process comprises plating on ABS polymer and/or ABS/PC polymer.

15. A method of manufacturing the support of claim 1, the method comprising the method of: providing a support for supporting a component to be plated in a chromic acid-free plating process, the support having a contact surface comprising plastic; providing an aqueous solution comprising one or both of iodine and bromine; and contacting at least a portion of the plastic of the contact surface of the support with the aqueous solution.

16. A process for plating a component, the process comprising: providing a component to be plated, the component having an outer surface comprising a plastic; providing a plating apparatus comprising a plating vessel having one or more supports for supporting a component to be plated, the one or more supports having a contact surface comprising iodine-treated and/or bromine-treated plastic; mounting the component on a support of the plating apparatus to provide a mounted component; contacting at least a portion of the plastic of the outer surface of the mounted component with an electrolyte to at least partially etch the plastic to form an etched surface of the component, the electrolyte being substantially free of chromic acid; contacting at least a portion of the etched surface of the component with an activator solution to form an activated surface of the component; and contacting at least a portion of the activated surface of the component with an electroless nickel solution or an electroless copper solution to form a plated surface of the component.

17. The process of claim 16, wherein: the iodine-treated and/or bromine-treated plastic comprises PVC, preferably PVC plastisol; and/or the plastic of the outer surface of the component comprises ABS and/or ABS/PC.

18. The process of claim 16, wherein: the electrolyte comprises manganese (III) ions in a solution of from 9 to 15 molar sulphuric or phosphoric acid; and/or the activator solution comprises a precious metal colloid, preferably wherein the precious metal colloid comprises a first core metal and a colloid metal that colloidally surrounds the core; the core metal comprises at least one metal selected from the group consisting of silver, platinum, palladium and nickel; and the colloid metal comprises at least one metal selected from the group consisting of tin and lead.

19. The process of claim 16, wherein the process further comprises electroplating the plated surface of the component, and wherein the support comprises metal at least partially coated with the iodine-treated and/or bromine-treated plastic.

20. A method of using an iodine and/or bromine pre-treatment on a support for supporting a component to be plated to inhibit plating thereon during a chromic acid-free plating process, wherein the support has a contact surface comprising plastic, the method comprising the steps of: contacting the contact surface comprising plastic with a solution of iodine and/or bromine to infuse iodine or bromine into a surface of the plastic.

Description

[0078] The invention will now be described with reference to the following non-limiting drawings, in which:

[0079] FIG. 1 shows a schematic of an example of a support according to the present invention.

[0080] FIG. 2 shows a cross section of part of the support of FIG. 1 along the line A-B.

[0081] FIG. 3 shows a schematic of an example of a plating apparatus according to the present invention.

[0082] FIG. 4 shows a flow chart of an example of a method according to the present invention.

[0083] FIG. 5 shows a flow chart of an example of a process according to the present invention.

[0084] Referring to FIGS. 1-3, there is depicted an example of a support (plating rack) 1 for use in a chromic acid-free plating process according to the present invention. The rack comprises a number of hooks or support clips 2 onto which a component to be plated may be mounted during a plating process. The support has a contact surface comprising iodine-treated and/or bromine-treated plastic 3. The interior of the support may comprise metal 4. At least a portion of the metal 4 of the support clips 2 is uncoated with the iodine-treated and/or bromine-treated plastic 3 so that it is capable of transmitting an electrical current to the component during plating. FIG. 3 shows a plating apparatus 5 for use in a chromic acid-free plating process, the plating apparatus 5 comprising a plating vessel 6 having one or more supports 1 having a contact surface comprising iodine-treated and/or bromine-treated plastic 3.

[0085] Referring to FIG. 4, there is shown a method 7 of treating a support for supporting a component to be plated in a chromic acid-free plating process, the support having a contact surface comprising plastic, the method comprising: [0086] i. providing a support for supporting a component to be plated in a chromic acid-free plating process, the support having a contact surface comprising plastic; [0087] ii. providing an aqueous solution comprising one or both of iodine and bromine; and [0088] ii. contacting at least a portion of the plastic of the contact surface of the support with the aqueous solution.

[0089] Referring to FIG. 5, there is shown a process 8 for plating a component, the process comprising: [0090] a. providing a component to be plated, the component having an outer surface comprising a plastic; [0091] b. providing a plating apparatus comprising a plating vessel having one or more supports for supporting a component to be plated, the one or more supports having a contact surface comprising iodine-treated and/or bromine-treated plastic; [0092] c. mounting the component on a support of the plating apparatus to provide a mounted component; [0093] d. contacting at least a portion of the plastic of the outer surface of the mounted component with an electrolyte to at least partially etch the plastic to form an etched surface of the component, the electrolyte being substantially free of chromic acid; [0094] e. contacting at least a portion of the etched surface of the component with an activator solution to form an activated surface of the component; and [0095] f. contacting at least a portion of the activated surface of the component with an electroless nickel solution or an electroless copper solution to form a plated surface of the component.

[0096] The process optionally further comprises: [0097] g. electroplating the plated surface of the component, and wherein the support comprises metal at least partially coated with the iodine-treated and/or bromine-treated plastic.

[0098] The invention will now be described in relation to the following non-limiting examples. All of the examples used the same piece of PVC plastisol coating.

Example 1 (Comparative Example)

[0099] A plating rack with a coating of PVC plastisol was treated using the following sequence (rinse stages omitted for brevity): [0100] 1. Immersion in an aqueous solvent blend containing 100 ml/l of propylene carbonate and 50 ml/l of butyrolactone at 35° C. for 3 minutes [0101] 2. Etching in a chromium-free etchant based on the teachings on patent US 10260000B2 (Evolve Etch by MacDermid Enthone) at 68° C. for 10 minutes [0102] 3. Immersion in a 30% solution of 35% w/w hydrochloric acid at ambient temperature for 30 seconds [0103] 4. Immersion in a proprietary palladium colloid solution (Evolve Activator by MacDermid Enthone) at ambient temperature for 3 minutes. [0104] 5. Immersion in a proprietary accelerating solution (Evolve Accelerator 800 by MacDermid Enthone) at 50° C. for 2 minutes [0105] 6. Immersion in an electroless nickel solution (Evolve EN-60 by MacDermid Enthone) at ambient temperature for 7 minutes Following this treatment, the entire plating rack was covered in a coating of nickel.

Example 2 (Comparative Example)

[0106] A plating rack with a coating of PVC plastisol was treated using the following sequence (rinse stages omitted for brevity): [0107] 1. Immersion in a solution containing 10 g/l of thiourea at 70° C. for 10 minutes [0108] 2. Immersion in an aqueous solvent blend containing 100 ml/l of propylene carbonate and 50 ml/l of butyrolactone at 35° C. for 3 minutes [0109] 3. Etching in a chromium-free etchant based on the teachings on patent US 10260000B2 (Evolve Etch by MacDermid Enthone) at 68° C. for 10 minutes [0110] 4. Immersion in a 30% solution of 35% w/w hydrochloric acid at ambient temperature for 30 seconds [0111] 5. Immersion in a proprietary palladium colloid solution (Evolve Activator by MacDermid Enthone) at ambient temperature for 3 minutes. [0112] 6. Immersion in a proprietary accelerating solution (Evolve Accelerator 800 by MacDermid Enthone) at 50° C. for 2 minutes [0113] 7. Immersion in an electroless nickel solution (Evolve EN-60 by MacDermid Enthone) at ambient temperature for 7 minutes [0114] 8. Plating in an acid copper electrolyte at ambient temperature for 40 minutes at a current density of 2 Adm.sup.−2

[0115] It was observed that after stage 6, no nickel coating was observed on the rack, but following stage 7, there was a significant amount of copper plating on the PVC plastisol coating.

Example 3

[0116] A plating rack with a coating of PVC plastisol was treated using the following sequence (rinse stages omitted for brevity): [0117] 1. Immersion in a solution containing 0.05M of iodine at ambient temperature for 5 minutes [0118] 2. Immersion in an aqueous solvent blend containing 100 ml/l of propylene carbonate and 50 ml/l of butyrolactone at 35° C. for 3 minutes [0119] 3. Etching in a chromium-free etchant based on the teachings on patent US 10260000B2 (Evolve Etch by MacDermid Enthone) at 68° C. for 10 minutes [0120] 4. Immersion in a 30% solution of 35% w/w hydrochloric acid at ambient temperature for 30 seconds [0121] 5. Immersion in a proprietary palladium colloid solution (Evolve Activator by MacDermid Enthone) at ambient temperature for 3 minutes. [0122] 6. Immersion in a proprietary accelerating solution (Evolve Accelerator 800 by MacDermid Enthone) at 50° C. for 2 minutes [0123] 7. Immersion in an electroless nickel solution (Evolve EN-60 by MacDermid Enthone) at ambient temperature for 7 minutes [0124] 8. Plating in an acid copper electrolyte at ambient temperature for 40 minutes at a current density of 2 Adm.sup.−2

[0125] Following this sequence, no nickel coating or copper plating was observed after treatment. This sequence was repeated for a further 4 cycles that omitted step 1. No plating on the PVC plastisol was observed over these cycles. It was confirmed that in the etching bath or any of the treatment steps, iodine did not undergo a change to form iodate ions.

Example 4

[0126] A plating rack with a coating of PVC plastisol was treated using the following sequence (rinse stages omitted for brevity): [0127] 1. Immersion in a solution containing 0.01 M of iodine at ambient temperature for 5 minutes [0128] 2. Immersion in an aqueous solvent blend containing 100 ml/l of propylene carbonate and 50 ml/l of butyrolactone at 35° C. for 3 minutes [0129] 3. Etching in a chromium-free etchant based on the teachings on patent US 10260000B2 (Evolve Etch by MacDermid Enthone) at 68° C. for 10 minutes [0130] 4. Immersion in a 30% solution of 35% w/w hydrochloric acid at ambient temperature for 30 seconds [0131] 5. Immersion in a proprietary palladium colloid solution (Evolve Activator by MacDermid Enthone) at ambient temperature for 3 minutes. [0132] 6. Immersion in a proprietary accelerating solution (Evolve Accelerator 800 by MacDermid Enthone) at 50° C. for 2 minutes [0133] 7. Immersion in an electroless nickel solution (Evolve EN-60 by MacDermid Enthone) at ambient temperature for 7 minutes [0134] 8. Plating in an acid copper electrolyte at ambient temperature for 40 minutes at a current density of 2 Adm.sup.−2

[0135] Following this sequence, no nickel coating or copper plating was observed after treatment. This sequence was repeated for a further 2 cycles that omitted step 1. No plating on the PVC plastisol was observed over these cycles. It was confirmed that in the etching bath or any of the treatment steps, iodine did not undergo a change to form iodate ions.

Example 5 (Comparative Example)

[0136] Two plating racks with coatings of different PVC plastisol were immersed in a solution of potassium iodate (30 g/l) at 70° C. for 20 minutes. No colour change was observed in the PVC plastisol of either plating rack. This is consistent with the colourless nature of potassium iodate solutions.

[0137] The foregoing detailed description has been provided by way of explanation and illustration, and is not intended to limit the scope of the appended claims. Many variations in the presently preferred embodiments illustrated herein will be apparent to one of ordinary skill in the art and remain within the scope of the appended claims and their equivalents.