Advances in Methods for Plating on Plastics Tout Advantages over Convent iona 1 Technologies

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1 ATOTECH ~ ~ ~ GmbH, T BERLIN S ~ H ~ ~ ~ Advances in Methods for Plating on Plastics Tout Advantages over Convent iona 1 Technologies Alternative plating procedures negate the need for chromic sulfuric acid, resulting in a more environmentally friendly process for electroplaters. lie beginning of commercial metal plating of plastic materials dates back to tlie 60s. This was the time when ABS (acrylonitrilebutadiene-styrene) was discovered as a basic material for an adhesively strong coating with outstanding moulding characteristics. Today, electroplating of plastics is-more than ever-subject to change. While the electroplating of plastics, with usually ABS and ABC/PC blends as the substrate, is applied for decorative plating techniques in the industry, functional and decorative coating of innovative materials is increasingly gaining significance. This is a great challenge for today s plating companies, since these innovative materials cannot be coated satisfactorily using tlie conventional tech ni q Lies (e. g., through the use of cliroinium-sulfuric acid). Therefore, innovative systems and processes, which take into account these new challenges, had to be developed. This means, apart from conventional coating technologies, the implementation of alternative processes. The 90s saw a revolution in metal plating of plastics: The Futuron technology or Direct Metallization, developed by Atotech, for tlie first time allowed direct coating of plastic surfaces. The main benefit of Futuron over conventional techniques is seen in at all the steps inherent ss metal-plating become To date, these steps Figure 1: Process Noviganth AK vs, Futuron. were absolutely necessary for tlie plating of a dielectric material. In the conventional process, electroless chemical nickel and copper baths were used after the plastic March 2007 I metalfinishing I 35

2 Fig. 2 -ABS and ABS/PC after the chromic-sulfuric acid, PA after swelling. I FINISHING EQUIPMENT SYSTEMS Auto Tecliiiology Cotnpany acquired UNIFIED CQlJIPMENl SYSTEMS (UCS) foniierly UJ)YI I fe EQ1JIf MI N1 CO Stniidard, custom and hard to find parts for all UDYLI I f inachiiies are availnble using the origiiial engineering and design data The Company will continue to engineer aid manufacture the CYCLLMAS I kk, SENIOR SPLIT-KAlI, C and b Enviroimental I est Chambers Cyclic Corrosion Chambers Salt 1 og & Huiiiidity Chambers Walk-in, Drive-in and Multi Gas test chambers Auto Technology Company! Progress Drive Strongsville 0 Ohio fel Fax (440) nww autotcchiiolonv net 0 salesiiijautotcclinologv net Centrifugal Dryers 75 to 800 pound capacity Choice o fm sizes Heating available for fast drying Circle 066 on reader information card or go to I surface had been prepared and activated. The galvanic coating was then applied to the electroless chemical deposition. With Futuron no electroless chemical metal plating is used. A poteiitial source of error is thereby eliminated in the plating-on-plastics process as well as the associated costs to operate such a process. So far, chromic sulfuric acid has been used as the etching process oil a large scale, and many years later plating of ABS and ABS/PC is still based on the same principle. By the use of alternative etching solutions it is now possible to apply adhesively strong coatings on a multitude of plastics, which had been previously unable to electroplate. An organic solvent is generally used as the swelling medium combined with a subsequent conditioning step. These process steps form the basis for adhesive metal plating. WW ORRCOM 239 East Stephenson Street, Freeport, IL (Tel) (Fax) sonic@upcorp.com In recent years, polyamide (PA) has proven to be a plastic material suitable for a great variety of industrial applications. Polyamide is inherently stronger and more rigid than ABS or ABS/ PC. As a thermoplastic, polyamide can be readily processed froin a liquid state. It has temperature stability from -30 C to around 110 C. In addition to this, it has excellent low-friction behavior and good thermal coefficiency expansion characteristics with the metals that are later electroplated. Polyamide Circle 067 on reader information card or go to www metalfinishing com/advertisers March 2007 I metalfinishing I36

3 has high impact strength, a small amount of memory (elasticity), is abrasion resistant, and vibration reducing l. The low-fusion viscosity of polyamides makes them easy to work. Put simply, polyamides have outstanding physical properties, combined with low weight and also low manufacturing costs. Polyamide is differentiated by the number of polar amid groups (PA 6, 11, 12, GG), which, at the same time, indicate the difference in the material compared to ABS-/ABS-PC blend plastics. Although the principal application of chromic-acidetching solutions attacks polyamide to a certain extent, it does not obtain the required decorative results. Another influencing variable are the fillers (in general, minerals such as glass fibers) Circle 031 on reader information card or go to March 2007 I metalfinishing I 37

4 which-depending on their condition-must be considered in the pre-treatment (Figures 2 & 3). The elimination of chromic sulfuric acid as the etching solution and the short but reliable pre-treatment of new substrates with a new swelling and conditioning solution is a further advantage of this novel process. The sweller and the coinpositioii of the subsequent solutions must be carefully tuned, since only carefully optimized parameters ensure good metal plating, with good adhesion. A process that is suitable for one type of plastic may be unsuitable for another, as each individual plastic material behaves differently. Even the slightest modifications within a plastic type may give deviating results at equivalent pretreatment methods. Both various pigments and a diversity of fillers can Fig. 4 - Application example automotive industry. Save Time and Money!!! rs Eliminate disposable media replacement costs Backwashing process performed minutes Double your filter efficiency and increase productivity All-plastic corrosion resistant construction ideal for many aggre a p p I i ca t i o n s AF SeriesTM Corrosion-Resistant Filters Global Filtration Systems, Inc. iiol,llc,iy ~lvlslon Aspill Aillclw Rt 25 PO. Box 10, Tamworth, NH Phone Fax, www alobalfiltratlonsvstems com * info@ qlobalfiltrationsystems com Circle 008 on reader information card or go to March 2007 I metalfinishing I 38 Circle 035 on reader information card or go to

5 influence plastic characteristics. Another influence, not to be underestimated, is the molding of the plastic material prior to the plating process. The development of new processing technologies and equipment will lead to potential savings in terms of raw material and energy. Atotech s new polyamide pretreatment method, Noviganth PA, offers many benefits for the electroplater, as no chromic-sulfuric acid is needed. The system is distinguished among other things by its ease of use and short but reliable pre-treatment. The system is especially suitable for mineral filled polyamides, which, for example, are used for door handles in the automotive industry. Thus, plating a strong but light plastic, such as polyamide, is seen as a contribution to the automotive industry s endeavors to reduce the weight and fuel consumption of vehicles. Smoothness of the surface (e.g., orange skin ) iii the plating of plastics plays an important role for appearance and adhesion of finished parts. With newly developed polyamide resins, such as Toyobo T772, the surface finish of the plated part resembles that of ABS or ABS/PC. This swelling and conditioning step should ensure uniform roughening and functionality of the surface. These steps form the ideal basis for the subsequent activation of the surface with precious metal ions, usually palladium-containing processes. Only an optimized pretreated surface will result in perfectly adhesive metal deposition. In an activation step, palladium will be adsorbed on the surface. The reduction step reduces the palladium, while a catalytic activation of the surface is generated on the plastic, which can then be nickelplated. The present method shows that a highly adhesive and decorative coating of polyamides can be ensured. Apart from extending the spectrum for production with regard to the above plastics, further advantages are achieved with the in o di fi e d p r e- t r ea tm en t o f polyamides. For example, better coating results are obtained not only through the fact that chromic-sulfuric acid is no longer necessary technically, as in the case of conventional processes, but also with respect to ecological concerns in the use of Cr(V1) or hexavalent chrome. Atotech s processes have gained a worldwide reputation as proveii methods for the metal plating of ABS, ABS/PC blends, PA, PC, and other plastics, and they are qualified by many major automotive manufacturers. Besides the automotive applications, numerous major manufacturers in the sani- You ve got anodizing problems. \Ve ve got anodizing solutions custom-designed to meet your needs, your deli~q~ schedule and your cost parameters. First, we listen to porir rcqniremeots. Then, using state-of-the-art Cornputer i\ided Design, oiir engiiineers input those requirements 8s part of the design process to produce wliatjou need to precisely fit your operation, whetlier it is titanium or aluiiiinum r;tcks or fasteners. And solving ixoblems at away So call or ckk today Clieckoiit the F,4Q \ 111 onr Technical Data wtion ~ 4QYears of Serving Customers Northbrook, IL CSA Toll-free (outcidc IL) Dit ect E-Mal tiisrewski@vuicaiiiuin coin ww7w.vulcanium.com Circte 053 on reader information card or go to Circle 014 on reader information card or go to w.metalfinishing.com March 2007 I metalfinishing I 39

6 tary industry have full confidence in these processes. The described systems are associated ~ ithighly adhesive, premium-quality, and extremely decorative coatings. Users will truly benefit from these characteristics, as economic and technical advantages are realized. 1. H. Domininghaus, Die I<unststoffe und ihre Eigenschaften, 5. lieu bearbeitete und erweiterte Auflage, Springer; (1998) 2. Witt, W., Kunststoffe 9, S ; Fahnler, F., Merten, F. Kuiiststoffe 75, S ; 19S5 4. Kunststoff-Metallisierung, Eugen G. Leuze Verlag, Saulgau Wiirtt; Brandes, M., Dr. C. Fels, MO Nr. 9; Technische Dokumentation Atotech Deutschland GmbH; Manola Brander has been involved with surjiacc technology since 1989 She pined Atotech Deutschland GmbH zn 1990, first working zn research and developnaent, and later swztched to woi*ldwzde pi-oduct management of plating on plastics and mpperprocesses. For more info!.- matzon, contact Atot-ech Deatschland GmbH Feucht Bernd Monch Pi.oduct Marketzng Manages POP Deutschland Tel / , (fax) / ; ( ) be rn d. m. o e n c a t o tech. c o m, www atotech.com. Remember when... - Customer Service really meant ~ ust~m~r Service7 - You didn t need a minimum order7 - Your supplier formulated products for your needs? - Your lab results were timely, free and meant something7 -A real person answered the phone? fashio~ed, but at we sf8 remember when oating Thickness Measurement Copper thickness measurement on pc-boards including copper thru hole readings. Thickness measurement of metallic coatings over nuts, bolts, and screws. re! www. Fisc h e r-tec h no I ogy. co m I I Circle 65 on reader information card or go to Circle 016 on reader information card or go to March 2007 I metalfinishing I40