JP7315793B2 - Prevention of unwanted plating on rack coating for electrodeposition - Google Patents

Description

The present invention relates to substrates for supporting components to be plated in chromate-free plating processes, plating apparatus for use in chromate-free plating processes, methods of treating substrates to support components to be plated in chromate-free plating processes, processes for plating components, and the use of iodine and/or bromine pretreatments on substrates to support plated components.

Plating on plastic (POP) is a technique that has a wide range of applications, for example in the automotive industry and shower and bathroom fixtures. The most common substrate for plating is a copolymer of acrylonitrile, styrene and butadiene known as ABS. It is a two-phase plastic consisting of a hard phase of acrylonitrile/styrene copolymer and a soft phase of polybutadiene. ABS polymers are sometimes combined with a proportion of polycarbonate to make ABS/PC. To plate these components, these components are mounted on metal racks to transmit the plating current to the components after the initial metallization stage. Metal plating racks are coated with a PVC plastisol coating to prevent the entire rack from being plated.

The plating process for ABS involves etching the plastic to roughen the surface so as to provide good adhesion during subsequent plating steps and render the surface sufficiently hydrophilic to completely wet it when immersed in an aqueous solution. Following the etching step, the non-conductive ABS must first be metallized with a thin layer of nickel or copper to make it conductive for subsequent plating operations. This is accomplished by immersing the plating rack holding the ABS component in an aqueous solution of a catalyst (typically a palladium colloid) which deposits a thin layer of catalyst on the plastic surface. This then acts as a catalyst for an electroless nickel or copper plating process that produces a thin metal layer on the ABS component. Aqueous solutions of such catalysts are known as activator solutions, and plastic surfaces treated with such baths are known as "activated" surfaces.

The initial etching step for the plating of ABS has traditionally been chromic and sulfuric acid solutions that (predominantly) oxidize the polybutadiene phase of the ABS, resulting in the necessary roughening of the plastic. The chromic acid solution is highly permeable and part of it is absorbed by the PVC plastisol material of the rack coating. After subsequent immersion in colloidal palladium, some of the colloids adhere to the PVC plastisol but are deactivated by the absorbed chromic acid. Therefore, when the rack holding the ABS component is immersed in an electroless nickel or copper solution, the catalyst adsorbed on the ABS component catalyzes the deposition of copper or nickel on the component, but due to the presence of chromic acid on the PVC plastisol on the rack coating, no nickel or copper is deposited on the rack coating.

Chromic acid is a Category 1 carcinogen and is under increasing legal pressure. Its use is currently being phased out in Europe. At present, it can only be used for a few approved applications, and even this limited use is likely to be restricted to the point of further exclusion.

Recently, a new method has been developed to etch ABS plastic using a combination of acid and manganese III ions (see, for example, Pearson U.S. Pat. Nos. 9,534,306 (B2) and 1,0260,000 (B2), the inserts of which are incorporated herein by reference). However, manganese-based etching does not inhibit palladium colloids adhering to PVC plastisol coatings sufficiently effectively to prevent nickel or copper deposition during the electroless deposition stage of the POP process. Several patents have been produced detailing compounds that can be used to treat PVC rack coatings to prevent this problem (e.g., Noffke EP3059277B1, Weitershaus US9506150B2, Middeke US9181622B2 and Herdman US201523301). 1(A1) and Dalbin, US Patent Application Publication No. 2019112712(A1), the inserts of which are incorporated herein by reference). Most of the compounds currently in use are organic sulfur compounds. While these are effective in preventing nickel or copper deposition during the electroless plating step, they can cause surprising problems during the electroplating step. The problem is that even though there is no detectable nickel or copper on the PVC plastisol coating after immersion in the electroless process, the rack becomes covered with copper during the acid copper plating step following the initial metallization of the ABS components. While not wishing to be bound by theory, it is believed that this is probably due to the reaction of adsorbed organosulfur compounds on the PVC coating with copper ions resulting in the formation of copper sulfide. This is a p-type semiconductor with high relative conductivity and, without being bound by theory, it is believed to be the primary reason that plating racks tend to be coated with copper. Therefore, there is a need for improved methods for inhibiting plating on PVC rack coatings during plating of ABS and ABS/PC when using processing techniques that do not involve the use of chromic acid.

WO2015/150156A1 relates to compositions and processes for metallizing non-conductive plastic surfaces. WO 2013/135862 A2 relates to a process for metallizing non-conductive plastic surfaces. Both literature processes use an iodate (IO ₃ ⁻ ) solution to pretreat the plating rack. Since no reducing agent is present in solution, the iodate ion remains an iodate ion and does not form iodine, ie I ₂ −. The effect of such pretreatment is described as "leading to extra protection of the plastic casing of the rack against metal deposits." One problem with such a process is that there is no visual change in the rack after pretreatment, so it is not possible to tell whether the rack has been pretreated or not. Therefore, it is necessary to either perform the pretreatment step every time the deposition process is performed, or accept the risk that the pretreatment was not performed or is less effective/ineffective.

The present invention seeks to address at least some of the problems associated with the prior art, or at least provide commercially acceptable alternatives thereto. In particular, the present invention seeks to provide improved substrates for use in chromate-free plating processes.

In a first aspect, the invention provides a support for supporting a component to be plated in a chromate-free plating process, the support having a contact surface comprising an iodinated and/or brominated plastic.

The inventors have surprisingly found that when components are mounted on a support during a chromate-free plating process, there may be substantially no deposition of copper or nickel on the support during the electroless deposition step, and substantially no deposition on the support during the subsequent electroplating step. Without wishing to be bound by theory, it is believed that, in contrast to organic sulfur treated supports, the contact surfaces of the supports of the present invention are not significantly activated as plated in an acid copper electroplating process.

Although iodated plastics are described in the prior art as being resistant to metal deposits, it is surprising that this effect is also exhibited by iodine-treated and/or bromine-treated plastics. This is because iodate and iodine are chemically very different, iodate being an ionic species ( _IO3- ⁾ comprising an iodine atom in the +5 oxidation state combined with an oxygen atom, whereas iodine is a covalent species ( _I2 ) comprising only the iodine atom in its elemental state (0 oxidation state).

Each aspect or embodiment defined herein may be combined with any other aspect or embodiment unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature indicated as being preferred or advantageous.

When introducing an element of the disclosure or its preferred embodiment(s), the supports "a", "an", "the", and "said" are intended to mean that one or more of the elements are present. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. The term "consisting of" is intended to mean that there can be no other elements other than those listed. The term "consisting essentially of" is intended to mean that no other elements other than those listed can be present unless such other elements materially affect the basic and novel characteristics of the invention.

The substrate is for use in a chromate-free plating process, preferably a plating-on-plastic ("POP") process. The plating process is substantially free of chromic acid, particularly substantially free of chromic acid during the etching step of the plating process.

The contact surface of the support is the (outside) surface that comes into contact with the etching and plating solutions during typical treatment processes. Typically substantially the entire contact surface of the support comprises iodinated and/or brominated plastic, more typically the entire contact surface of the support comprises iodinated and/or brominated plastic.

The contact surface of the support comprises (or consists essentially of or consists of) an iodinated and/or brominated plastic. By "treated" is meant that the plastic contains iodine and/or bromine, typically by contact with a solution of iodine and/or bromine (ie _I2 and/or _Br2 ). While not wishing to be bound by theory, it is believed that iodine and/or bromine (ie, _I2 and/or _Br2 ) are infused into the surface of the plastic as a result of contact. In other words, the iodine-treated and/or bromine-treated plastics may be iodine- and/or bromine-infused plastics, respectively (ie molecular iodine/ _I2 -infused and/or molecular bromine/ _Br2- infused plastics). The implantation of iodine and/or bromine into plastics can be observed by a change in the color of the plastic, typically brown for iodine-infused plastics and orange for bromine-infused plastics. The use of iodine and/or bromine changes the color of the plastic, so in contrast to the use of iodate solutions in conventional processes, the present invention may allow the user to identify whether the plastic has been treated. Over time and/or long-term use, the effectiveness of the iodine and/or bromine treatment may decrease and the color of the plastic may change accordingly, allowing the operator to identify when further treatment to the substrate may be required.

The contact surface comprises iodine treated and/or bromine treated plastic. The contact surface preferably comprises iodine treated plastic. Bromine is still effective, but is not as persistent on plastic surfaces as iodine.

The plastic preferably comprises (or consists essentially of or consists of) PVC, more preferably PVC plastisol. PVC or polyvinyl chloride is produced by the polymerization of vinyl chloride monomers. PVC plastisol comprises a suspension of PVC particles in a liquid plasticizer. Iodine and/or bromine treatment of such materials may be particularly effective in inhibiting plating of such materials during electroless and/or electroplating.

The support preferably comprises metal at least partially coated with plastic. The presence of metal can allow the plating current to pass through the components supported by the support during the electroplating process. The metal preferably comprises copper and/or iron alloys. The metal may function as an electrode (cathode or anode) during the electroplating process. Specifically, the support for holding the component is typically made of metal in order to transmit the current to the component during electroplating. The components are typically held in place on the support by spring contacts or clips, hereinafter referred to as support clips. In order to carry the current, these support clips necessarily have a small uncoated area so that electrical contact is maintained during component processing. The remainder of the support is coated with an insulating plastic coating, typically PVC, to prevent the entire support from being electroplated. This coated surface is hereinafter referred to as the support contact surface. Typically, the portion of the support that contacts the power supply for supplying the electroplating current, typically the upper portion of the support, is not immersed in the processing solution and is therefore uncoated.

The support preferably comprises a plating rack. Plating racks are particularly suitable for supporting one or more components during the plating process. Suitable rack shapes and configurations are known in the art. The rack may include, for example, one or more hooks or support clips to support the component during the plating process. The racks may contain cathodes and/or anodes for use in electroplating processes.

In a further aspect, the invention includes a plating apparatus for use in a chromate-free plating process, the plating apparatus including a plating vessel having one or more supports for supporting components to be plated, the one or more supports having contact surfaces comprising iodinated and/or brominated plastics.

For the avoidance of doubt, the advantages and preferred features of other aspects of the invention apply equally to this aspect.

The support may be any support described herein.

A plating vessel typically has a shape and size suitable to contain the components to be plated during the plating process. Such plating vessels are known in the art. The inner surface, or contact surface, of the container is typically substantially inert to the etchants and plating solutions used in the plating process.

In a further aspect, the invention provides a method of treating a support for supporting a component to be plated in a chromate-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 chromate-free plating process, the support having a contact surface comprising a plastic;
providing an aqueous solution comprising one or both of iodine and bromine;
contacting at least a portion of the plastic of the contact surface of the support with an aqueous solution.

For the avoidance of doubt, the advantages and preferred features of other aspects of the invention apply equally to this aspect.

As in the first aspect, when a support is used in a chromate-free plating process, there may be substantially no copper or nickel deposition on the support during subsequent electroless deposition steps, and substantially no deposition on the support during subsequent electroplating steps.

Treatment may result in a support as described herein. The support may comprise, for example, a plating rack.

The plastic contact surface of the support may contact the component to be plated during plating and may contact etchants and/or plating solutions used in the plating process.

The aqueous solution contains one or both of iodine and bromine, molecular iodine (I ₂ ) and molecular bromine (Br ₂ ).

Contacting at least a portion of the plastic of the contact surface of the support with the aqueous solution typically includes at least partially immersing the support in the aqueous solution, more typically completely immersing the support in the aqueous solution.

Contacting may occur, for example, at ambient temperature to 100°C. Since it works well at ambient temperature, it is preferred to carry out the method at ambient temperature to reduce costs and improve safety.

The aqueous solution preferably contains iodine. Bromine is still effective, but is not as persistent on plastic surfaces as iodine.

The aqueous solution preferably contains, but is not limited to, 0.005-0.1M iodine, more preferably 0.01-0.05M iodine. The use of such iodine concentrations is particularly effective in inhibiting plating on the substrate during the plating process.

The aqueous solution preferably contains iodide ions. Iodine (I ₂ ) is not particularly soluble in water. The presence of iodide ions can increase the solubility of iodine in aqueous solutions. For example, the presence of iodide ions can form an aqueous solution containing up to 12% iodine. Iodide may be introduced into the aqueous solution, for example in the form of potassium iodide.

The molar ratio of iodide ion to iodine in the aqueous solution is preferably at least 1:1, more preferably at least 1.5:1, even more preferably at least 2:1. By setting such a ratio, the aqueous solution can advantageously contain a large amount of iodine.

Alternatively, other suitable means of increasing iodine solubility are applicable, such as introducing a co-solvent in an amount effective to solubilize the desired concentration of iodine. Suitable solvents are numerous and may include, but are not limited to, alcohols, glycols and alkylene carbonates.

The step of providing an aqueous solution preferably comprises contacting iodate ions with iodide ions in the aqueous solution. From a commercial point of view, it is undesirable to dissolve iodine in, for example, a potassium iodide solution to provide both iodide and iodide ions in the aqueous solution. Advantageously, contacting iodide ions with iodate ions produces iodine in situ according to the following chemical reaction.
IO ₃ ⁻ +5I ⁻ +6H ⁺ →3H ₂ O+3I ₂

Other oxidizing agents capable of oxidizing iodide ions to iodine can be used instead of iodate ions. For example, persulfate ions, nitrate ions or hydrogen peroxide can be used. The invention is not limited by the type of oxidizing agent used to oxidize iodide ions to iodine. Iodide ions are typically preferred in excess over the oxidizing agent.

If the aqueous solution contains bromine, bromine may be generated in situ using the corresponding bromate/bromide reaction.

The support is preferably contacted with the aqueous solution for at least 10 seconds, more preferably at least 30 seconds, even more preferably 1-10 minutes, even more preferably 1-5 minutes. Such contact times can result in the support being particularly resistant to plating. Longer contact times can only lead to negligible improvement in plating resistance.

The plastic of the contact surface of the support preferably comprises (or consists essentially of or consists of) PVC, more preferably PVC plastisol. Iodine and/or bromine treatment of such materials may be particularly effective in inhibiting plating of such materials during electroless and/or electroplating.

The plating process preferably includes plating onto ABS polymer and/or ABS/PC polymer. Such plating processes are particularly prone to plating on other plastic substrates used in the process, such as plastic substrates. ABS or "acrylonitrile butadiene styrene" has the chemical formula ( _C8H8 ) _x .( _C4H6 ) _{y .} ( _C3H3N ) _z ) and is _a common thermoplastic _polymer known in the art. ABS/PC comprises a blend of acrylonitrile butadiene styrene and polycarbonate.

In a further aspect, the invention provides methods of making the supports described herein, including the processing methods described herein.

For the avoidance of doubt, the advantages and preferred features of other aspects of the invention apply equally to this aspect.

In a further aspect, the invention provides a process for plating a component, the process comprising:
providing a component to be plated, the component having an outer surface comprising plastic;
providing a plating apparatus including a plating vessel having one or more supports for supporting components to be plated, wherein the one or more supports have contact surfaces comprising iodinated and/or brominated plastic;
mounting the component on a support of the plating apparatus to provide the mounted component;
contacting at least a portion of the plastic of the exterior 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 forming a surface 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;
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.

For the avoidance of doubt, the advantages and preferred features of other aspects of the invention apply equally to this aspect.

The plating apparatus may include the plating apparatus described herein. The support may include any support described herein.

A "pre-etching" step may be performed prior to contacting at least a portion of the plastic on the exterior surface of the attached component with the electrolyte. This may involve, for example, contacting at least a portion of the plastic of the exterior surface of the mounted component with an aqueous solvent blend containing propylene carbonate and butyrolactone. Such a pre-etch step is not necessary, but can be modified to make it easier to etch the plastic surface.

Suitable chromate-free electrolytes are known in the art. Contacting at least a portion of the plastic of the exterior surface of the attached component with the electrolyte preferably includes at least partially immersing the attached component in the electrolyte, more preferably fully immersing the attached component in the electrolyte. Contacting may take place at room temperature. However, the contacting is preferably carried out at an elevated temperature, such as above ambient temperature, more preferably above 30°C, even more preferably above 50°C, even more preferably above 60°C. Such high temperatures can help provide a suitable level of etching. Contacting is preferably carried out at a temperature below 100°C, more preferably below 90°C, even more preferably below 80°C, in order to avoid loss of electrolyte. Contacting is preferably carried out for at least 30 seconds, more preferably at least 1 minute, even more preferably at least 5 minutes, even more preferably 1-30 minutes, even more preferably 5-20 minutes. Such contact times can provide adequate levels of etching.

Suitable activator solutions are known in the art. Contacting at least a portion of the etched surface of the component with the activator solution preferably comprises at least partially immersing the etched component in the activator solution, more preferably fully immersing the etched component in the activator solution. Contacting is typically carried out at ambient temperature, although elevated temperatures may be used. Contacting is preferably carried out for at least 30 seconds, more preferably at least 1 minute, even more preferably 1-20 minutes, even more preferably 1-10 minutes.

Prior to contacting at least a portion of the etched surface of the component with the activator solution, the etched surface may be contacted with an acid, such as hydrochloric acid. This is because typical activators sometimes contain colloids that exhibit limited stability in water. Directly immersing a wet plastic surface in a colloidal solution may destabilize the colloid on the plastic surface.

Suitable electroless nickel and electroless copper solutions are known in the art. A typical electroless solution contains nickel or copper ions along with a reducing agent, such as a hypophosphite reducing agent. Contacting at least a portion of the activated surface of the component with the electroless nickel or copper solution preferably comprises at least partially immersing the activated component in the electroless nickel or copper solution, more preferably fully immersing the activated component in the electroless nickel or copper solution.

After the component is typically contacted with the electrolyte and/or activator solution and/or electroless nickel solution and/or electroless copper solution, it is more typically rinsed in water before the next step.

Components may typically include any plastic component that needs to be electroplated. Examples include automotive supports (e.g., automotive grilles, headlamp surrounds, door handles, and ornaments), shower accessory supports, bathroom accessory supports, household and furniture accessories and electronic components (e.g., cameras, computers, phones).

The iodine-treated and/or bromine-treated plastic preferably comprises (or consists essentially of or consists of) PVC, more preferably PVC plastisol, with the exception of iodine and/or bromine.

The plastic of the outer surface of the component preferably comprises (or consists essentially of or consists of) ABS and/or ABS/PC.

The etching electrolyte may be any suitable etching electrolyte that is substantially free of chromium (VI) and may include, for example, permanganate ions or other strong oxidizing agents. Preferred electrolytes contain manganese (III) ions, preferably in a 9-15 molar sulfuric or phosphoric acid solution. Such electrolytes are particularly effective for etching plastics without the use of chromic acid.

It preferably contains an activator solution, a precious metal colloid. More preferably, the noble metal colloid comprises a first core metal and a second colloidal metal colloidally surrounding the core, the core metal comprising at least one metal selected from the group consisting of silver, platinum, palladium and nickel, with palladium being particularly preferred, the second colloidal metal comprising at least one metal selected from the group consisting of tin and lead, with tin being particularly preferred. The core metal can catalytically activate the deposition of electroless copper or electroless nickel. Such activator solutions are particularly effective in promoting nickel or copper deposition in subsequent electroless plating steps. An example of a suitable commercially available activator is MacDermid Enthone's Evolve Activator.

After contacting at least a portion of the etched surface of the component with the activator solution, at least a portion of the etched surface can be contacted with an accelerating solution. This can help remove the colloidal metal from the core catalytic metal, which otherwise may be masked and may be ineffective. In other words, the post-activation treatment removes the second colloidal metal from the activated surface, thereby exposing the first core metal and enabling catalytic function. Suitable accelerating solutions are known in the art. Accelerating solutions can vary widely in composition and can be acidic or alkaline. Preferably, the accelerating solution is acidic and may, for example, contain chloride ions in combination with organic and inorganic acids. An example of a suitable commercially available accelerator is MacDermid Enthone's Evolve Accelerator.

Contacting at least a portion of the etched surface of the component with the accelerating solution preferably includes at least partially immersing the etched and activated component in the accelerating solution, more preferably fully immersing the etched and activated component in the accelerating solution. Contacting is typically performed at an elevated temperature (eg, 50° C.), although ambient or higher temperatures may be used. Contacting is preferably carried out for at least 30 seconds, more preferably at least 1 minute, even more preferably 1-20 minutes, even more preferably 1-10 minutes.

In preferred embodiments, the process further comprises electroplating the plated surface of the component, wherein the substrate comprises metal at least partially coated with an iodinated and/or brominated plastic. As noted above, the presence of metal can allow penetration of the plating current to the component during the electroplating process. Electroplating preferably includes copper electroplating.

In a further aspect, the invention provides a component plated according to the processes described herein.

For the avoidance of doubt, the advantages and preferred features of other aspects of the invention apply equally to this aspect.

In a further aspect, the present invention provides the use of an iodine and/or bromine pretreatment on a support to support a component to be plated, the use of which inhibits plating thereon during a chromate-free plating process, the support having a contact surface comprising plastic.

For the avoidance of doubt, the advantages and preferred features of other aspects of the invention apply equally to this aspect.

The invention will now be described with reference to the following non-limiting drawings.
1 is a schematic illustration of an example of a support according to the invention; FIG. Figure 2 is a cross-sectional view of a portion of the support of Figure 1 along line AB; 1 shows a schematic diagram of an example of a plating apparatus according to the present invention; FIG. 1 shows a flowchart of an example of a method according to the invention; 1 shows a flowchart of an example of a process according to the invention;

1-3, an example of a support (plating rack) 1 for use in a chromate-free plating process according to the present invention is shown. The rack contains several hooks or support clips 2 to which components to be plated can be attached during the plating process. The support has a contact surface comprising an iodinated and/or bromine treated plastic 3 . The interior of the support may contain metal 4 . At least part of the metal 4 of the support clip 2 is not coated with the iodinated and/or bromine treated plastic 3 so as to be able to conduct current to the component during plating. FIG. 3 shows a plating apparatus 5 for use in a chromate-free plating process, the plating apparatus 5 comprising a plating vessel 6 having one or more substrates 1 with contact surfaces comprising iodinated and/or brominated plastics 3.

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

Referring to FIG. 5, a process 8 for plating components is shown, which process comprises:
a. providing a component to be plated, the component having an outer surface comprising plastic;
b. providing a plating apparatus including a plating vessel having one or more supports for supporting components to be plated, wherein the one or more supports have contact surfaces comprising iodinated and/or brominated plastic;
c. mounting the component on a support of the plating apparatus to provide the mounted component;
d. contacting at least a portion of the plastic of the exterior 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 forming a surface substantially free of chromic acid;
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;
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.

The process further optionally comprises:
g. electroplating the plated surface of the component, the substrate comprising a metal at least partially coated with an iodinated and/or brominated plastic;

The invention will now be discussed with reference to the following non-limiting examples. All examples used the same piece of PVC plastisol coating.

Example 1 (comparative example)
A plating rack with a coating of PVC plastisol was treated using the following sequence (rinsing step omitted for brevity).
1. 2. Immersion for 3 minutes at 35°C in an aqueous solvent blend containing 100 mL/l propylene carbonate and 50 mL/l butyrolactone. 2. Etch at 68°C for 10 minutes in a chromium-free etchant based on the teachings of US Patent No. 10260000 (B2) (Evolve Etch of MacDermid Enthone). 4. Immersion in a 30% solution of 35% w/w hydrochloric acid for 30 seconds at ambient temperature. Immersion in a proprietary palladium colloid solution (MacDermid Enthone's Evolve Activator) for 3 minutes at ambient temperature.
5. 6. Immersion in proprietary accelerating solution (Evolve Accelerator 800 from MacDermid Enthone) for 2 minutes at 50°C. Immerse in electroless nickel solution (Evolve EN-60 from MacDermid Enthone) for 7 minutes at ambient temperature

After this treatment, the entire plating rack was covered with a coating of nickel.

Example 2 (comparative example)
A plating rack with a coating of PVC plastisol was treated using the following sequence (rinsing step omitted for brevity).
1. 2. Immersion in a solution containing 10 g/l thiourea at 70°C for 10 minutes. 2. Immersion for 3 minutes at 35°C in an aqueous solvent blend containing 100 mL/l propylene carbonate and 50 mL/l butyrolactone. 4. Etch at 68° C. for 10 minutes in a chromium-free etchant based on the teachings of US Pat. No. 10,260,000 (Evolve Etch of MacDermid Enthone). 5. Immerse in a 30% solution of 35% w/w hydrochloric acid for 30 seconds at ambient temperature. Immersion in a proprietary palladium colloid solution (MacDermid Enthone's Evolve Activator) for 3 minutes at ambient temperature.
6. 7. Immersion in proprietary accelerating solution (Evolve Accelerator 800 from MacDermid Enthone) for 2 minutes at 50°C. 8. Immerse in electroless nickel solution (Evolve EN-60 from MacDermid Enthone) for 7 minutes at ambient temperature. Plating in an acidic copper electrolyte at a current density of 2 Adm ⁻² for 40 minutes at ambient temperature

After step 6, no nickel coating was observed on the rack, but after step 7, a significant amount of copper plating was observed on the PVC plastisol coating.

Example 3
A plating rack with a coating of PVC plastisol was treated using the following sequence (rinsing step omitted for brevity).
1. 2. Immersion in a solution containing 0.05 M iodine for 5 minutes at ambient temperature. 2. Immersion for 3 minutes at 35°C in an aqueous solvent blend containing 100 mL/l propylene carbonate and 50 mL/l butyrolactone. 3. Etch at 68° C. for 10 minutes in a chromium-free etchant based on the teachings of US Pat. No. 10260000 (B2) (Evolve Etch of MacDermid Enthone). 4. Immerse in a 30% solution of 35% w/w hydrochloric acid for 30 seconds at ambient temperature. Immersion in a proprietary palladium colloid solution (MacDermid Enthone's Evolve Activator) for 3 minutes at ambient temperature.
6. 7. Immersion in proprietary accelerating solution (Evolve Accelerator 800 from MacDermid Enthone) for 2 minutes at 50°C. 8. Immerse in electroless nickel solution (Evolve EN-60 from MacDermid Enthone) for 7 minutes at ambient temperature. Plating in an acidic copper electrolyte at a current density of 2 Adm ⁻² for 40 minutes at ambient temperature

After this sequence, no nickel coating or copper plating was observed after treatment. This sequence was repeated for 4 more cycles and step 1 was omitted. No plating on PVC plastisol was observed over these cycles. It was confirmed that the iodine was not changed to form iodate ions in the etching bath or any processing steps.

Example 4
A plating rack with a coating of PVC plastisol was treated using the following sequence (rinsing step omitted for brevity).
1. 1. Immersion in a solution containing 0.01 M iodine for 5 minutes at ambient temperature. 2. Immersion for 3 minutes at 35°C in an aqueous solvent blend containing 100 mL/l propylene carbonate and 50 mL/l butyrolactone. 4. Etch at 68° C. for 10 minutes in a chromium-free etchant based on the teachings of US Pat. No. 10,260,000 (Evolve Etch of MacDermid Enthone). 5. Immerse in a 30% solution of 35% w/w hydrochloric acid for 30 seconds at ambient temperature. Immersion in a proprietary palladium colloid solution (MacDermid Enthone's Evolve Activator) for 3 minutes at ambient temperature.
6. 7. Immersion in proprietary accelerating solution (Evolve Accelerator 800 from MacDermid Enthone) for 2 minutes at 50°C. 8. Immerse in electroless nickel solution (Evolve EN-60 from MacDermid Enthone) for 7 minutes at ambient temperature. Plating in an acidic copper electrolyte at a current density of 2 Adm ⁻² for 40 minutes at ambient temperature

After this sequence, no nickel coating or copper plating was observed after treatment. This sequence was repeated for two more cycles and step 1 was omitted. No plating on PVC plastisol was observed over these cycles. It was confirmed that the iodine was not changed to form iodate ions in the etching bath or any processing steps.

Example 5 (comparative example)
Two plating racks with different PVC plastisol coatings were immersed in a solution of potassium iodate (30 g/l) at 70° C. for 20 minutes. No color change was observed with the PVC plastisol on any of the plating racks. This is consistent with the colorless nature of potassium iodate solutions.

The foregoing detailed description has been provided by way of illustration and illustration and is not intended to limit the scope of the appended claims. Many variations of the presently preferred embodiments shown herein will be apparent to those skilled in the art and remain within the scope of the appended claims and their equivalents.

Claims (9)

A process for plating a component, said process comprising:
providing a component to be plated, said component having an outer surface comprising plastic;
providing a plating apparatus including a plating vessel having one or more supports for supporting components to be plated, wherein the one or more supports have contact surfaces comprising iodinated and/or brominated 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 exterior 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 forming a surface 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;
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. The one or more supports are
providing a support for supporting a component to be plated in a chromate-free plating process, said support having a contact surface comprising a plastic;
providing an aqueous solution comprising one or both of iodine and bromine;
contacting at least a portion of said plastic of said contact surface of said support with said aqueous solution. The iodine-treated and/or bromine-treated plastic is PVthe Cincludes and/or
the plastic of the outer surface of said component comprises ABS and/or ABS/PC, and/or
the electrolyte comprises manganese(III) ions in a solution of 9-15 molar sulfuric acid or phosphoric acid, and/or
the activator solution contains a precious metal colloid;,BeforeThe noble metal colloid comprises a first core metal and a colloidal metal colloidally surrounding the core, the core metal comprising at least one metal selected from the group consisting of silver, platinum, palladium, and nickel, the colloidal metal comprising at least one metal selected from the group consisting of tin and lead, and/or
4. The claim wherein said process further comprises electroplating said plated surface of said component, said substrate comprising metal at least partially coated with said iodine treated and/or bromine treated plastic.1 or 2process described in . 3. The process of claim 2, wherein said aqueous solution comprises iodine. 5. The process of claim 4, wherein the aqueous solution contains 0.005-0.1M iodine. 6. A process according to claim 4 or 5, wherein the aqueous solution contains iodide ions. 7. The process of claim 6, wherein the molar ratio of iodide ions to iodine is at least 1:1. 8. The process of any of claims 4-7, wherein the step of providing the aqueous solution comprises contacting iodide ions with an oxidizing agent in an aqueous solution, the oxidizing agent being selected from iodate ions, persulfate ions, nitrate ions, hydrogen peroxide and combinations of two or more thereof. 3. The process of claim 2, comprising contacting said support with said aqueous solution for at least 10 seconds.