23 June 2017 Surface and Coatings Forum 2017 1 Technology update plating on plastic for sustainability TOP ZECROM PROCESS Toshimitsu NAGAO OKUNO CHEMICAL INDUSTRIES CO., LTD. OSAKA JAPAN
Outline: Plating on Plastic (POP) technology 2 Introduction Product performance Using in industrial fields Equipment specifications Waste water treatment Mass-production
Usage: Plating on Plastic (POP) 3 Photo : Presented by LIXIL CORP Automotive parts Sanitary parts Electronic parts Amusement
Process: Plating on Plastic (POP) 4 Electroless plating process Electroplating process ABS resin Cleaning Etching Problem : use Chromic acid Ensure adhesion Acid activation Strike plating Acid copper plating For beautiful appearance Neutralization Catalyzing Semi-bright Ni plating Bright Ni plating Enhance corrosion resistance Activation Give conductivity Micro-porous Ni plating Electroless plating Cr plating Cr(Ⅵ) plating Alternative method: Cr(Ⅲ) plating
Current problem: Chromium etching solution 5 Chromic acid-sulfuric acid bath SEM and TEM images after etching Resin surface Cross section of resin Plating めっき皮膜 film 5mm Substrate: ABS ABS resin 樹脂 1mm Advantages Make surface roughness Increase adhesion between resin and deposit Ensure deposition on all of surfaces bath stability: semi-permanent Single rack system can be applied Disadvantages High concentration (chromic anhydride 400g/L), bath temp. is high (68 ) Carcinogenic, bad work environment Corrosive to equipment Waste water treatment: difficult If dragged out, decrease chemical performances If scattered in the air, prevent deposition
Requirements for eco-friendly products 6 ELV Directive, WEEE Directive, RoHS Directive: Regulate toxic materials in deposits REACH regulation: Regulate the use of toxic materials Chromic acid: SVHC (Substance of Very High Concern) If not approved after application, can t be used Considering future regulations about chemicals for plating, alternative eco-friendly methods are highly demanded.
Current problem: Acidic permanganate etching solution 7 CrO 2-4 + 8H + + 3e - Cr 3+ + 4H 2 O MnO - 4 + 8H + + 5e - Mn 2+ + 4H 2 O E 0 (V) E 0 (V) -1.48-1.51 Mn(Ⅶ) After make-up After 5 hours MnO 2 Mn(Ⅱ) By reduction from Mn(Ⅶ) to Mn(Ⅱ), manganese dioxide (MnO 2 ) precipitates.
TOP ZECROM ETCHANT : Mechanism 8 Improve bath stability = Inhibit MnO 2 formation Mn(Ⅶ) Mn(Ⅳ) Mn(Ⅱ) MnO 2 Developed the stabilizer increase MnO 2 solubility (Currently patents pending) (Precipitation)
TOP ZECROM PROCESS 9 ZERO CHROME ZECROM Etching process without chromium for ABS and ABS/PC resins (Currently patents pending)
Effect of Stabilizer Mn(Ⅶ) concentration (%) 10 Solubility of manganese dioxide (MnO 2 ) Stability of Mn(Ⅶ) No.1: Etchant without stabilizer No.2: Etchant with stabilizer :With stabilizer ;Without stabilizer Bath leaving time (day) By increasing the solubility of manganese dioxide (MnO 2 ), greatly improves the stability of Mn(Ⅶ)
Bath composition & treatment condition of TOP ZECROM ETCHANT 11 Standard Range Role TOP ZECROM ETCHANT A 55 ml/l 50 to 60 ml/l Mn(Ⅱ) Conc. solution TOP ZECROM ETCHANT B 510 ml/l 490 to 530 ml/l Stabilizer 98% H 2 SO 4 400 ml/l 385 to 415 ml/l Acid base Bath temp. 68 66 to 70 Treatment time 20 min. 10 to 40 min. Tank material Agitation Heating device Air exhauster Remark Fluoride tank made of PFA, PTFE, PVDF etc. Air and mechanical agitation PTFE coil heater Local exhaust system (not made of metal) Electrolytic regenerator is essential
TOP ZECROM PROCESS 12 Electroless plating process Direct acid copper plating process Etching TOP ZECROM ETCHANT Etching TOP ZECROM ETCHANT Reduction 35% HCl 100 ml/l Reduction 35% HCl 100 ml/l Catalyzing TOP ZECROM CATALYST Conditioner TOP ZECROM CONDITIONER Activation 35% HCl 100 ml/l Catalyzing TOP ZECROM CATALYST D Electroless Ni TOP ZECROM CHEMICAL NICKEL Conductor TOP ZECROM SELECTOR Strike Ni Watts nickel bath Electroplating TOP DuNC PROCESS Electroplating TOP DuNC PROCESS Mainly same with conventional steps
Plating appearances 13 Automobile part (4 dm 2 ) Direct copper plating process Shoehorn (0.8 dm 2 ) Left: Electroless Ni plating process Right: Direct copper plating process Sanitary part (2 dm 2 ) Electroless Ni plating process Beautiful plating appearance to molded parts
Requirements for chromium-free etchant 14 Chromic acid etching (ⅰ) High adhesion by forming micro-pores (ⅱ) High bath stability, can use semi-permanently (ⅲ) Single rack system can be applied (Chromium works as a poison in plating steps) Requirements for TOP ZECROM PROCESS Micro-pore formation Strong plating adhesion : Equal to chromic acid etching Continuous operation Single rack : Long bath life : Prevent deposition on jigs without poisons Plating appearances : No impact on following steps
TOP ZECROM PROCESS 15 Micro-pore formation and plating adhesion
SEM images after etching (Substrate: ABS Resin) 16 Substrate: UMG ABS 3001M (Etching bath temp. : 68 ) 5 min. 10 min. 20 min.(standard) TOP ZECROM ETCHANT Mn(Ⅶ) 5 min. 10 min.(standard) 20 min. Chromic acid Cr(Ⅵ)
SEM images after etching (Substrate: PC/ABS Resin) 17 Substrate: TC-37M, PC ratio 50% (Etching bath temp.: 68 ) 5 min. 10 min. 20 min.(standard) TOP ZECROM ETCHANT Mn(Ⅶ) 5 min. 10 min.(standard) 20 min. Chromic acid Cr(Ⅵ)
Peel Strength (N/cm) Peel Strength (N/cm) Plating adhesion (by Peel strength) 18 ABS resin (UMG ABS 3001M) PC/ABS resin (TC-37M, PC ratio 50%) 14 14 12 12 10 10 8 8 6 6 4 4 2 2 0 Cr(Ⅵ) Mn(Ⅶ) Cr(Ⅵ) Mn(Ⅶ) 0 Cr(Ⅵ) Mn(Ⅶ) Cr(Ⅵ) Mn(Ⅶ) Electroless plating process Direct acid copper plating process Electroless plating process Direct acid copper plating process TOP ZECROME PROCESS can ensure the same adhesion with chromic acid etching
Evaluation Results by Resin Grade 19 Resin Resin grade Plating deposition property Peel strength (N/cm) UMGABS 3001M (UMG ABS, LTD.) Overall deposition 11 to 13 ABS TECHNO ABS25 (Techno Polymer Co., Ltd.) Overall deposition 10.5 to 13 KRALASTIC AP8A (NIPPON A & L INC.) Overall deposition 10 to 12 TC-37M (UMG ABS, LTD.) Overall deposition 10.5 to 12 PC/ABS Iupilon PL-2010 (Mitsubishi Engineering-Plastics Corporation ) Overall deposition 11 to 14 Iupilon PL-2020 (Mitsubishi Engineering-Plastics Corporation ) Overall deposition 10 to 14
Plating Adhesion evaluation (By thermal cycle test) 20 (Plating film thickness: Cu 30μm, Ni 25μm, Cr 0.3μm) -30 60 min. 25 5 min. 80 60 min. 25 5 min. 20 cycles Process Resin Result Electroless plating process Direct acid copper plating process ABS PC/ABS ABS PC/ABS Good Good Good Good High adhesion can be realized in all of processes and materials
TOP ZECROM PROCESS 21 Continuous Operation
Continuous operation test Peel strength (N/cm) 22 Standard Range Analysis method TOP ZECROM ETCHANT A 55 ml/l 50 to 60 AAS or ICP TOP ZECROM ETCHANT B 510 ml/l 490 to 530 Titration or 98% Sulfuric acid 400 ml/l 385 to 415 specific gravity Mn(Ⅶ) (mg) 400 to 800 Titration Initial make-up After treatment of 1000dm 2 /L Amount of treatment (dm 2 /L) By proper concentration control, etching ability can be realized continuously
Equipment specifications for TOP ZECROM ETCHANT 23 Tank and piping material Agitation PFA, PTFE, PVDF Air agitation Bath load 0.1 dm 2 /L Anode Anode area Cathode Cathode solution Cathode area Pt/Ti or Pb Equivalent to or larger than substrate areas Zr (Using unglazed diaphragm) TOP ZECROM ETCHANT made-up solution About 50 % to anode areas Anode current density Below 1.5 A/dm 2 Bath voltage Mn 7+ regeneration speed 3 to 6 V 44 mg/ah (Mn 7+ consumption speed per 20 minute etching : 8 mg/dm 2 )
Image of electrolytic regenerator 50 L tank 200 L tank 24 Zr Rectifier Pt-Ti Electrolytic oxidation
TOP ZECROM PROCESS 25 Impact on following steps by drag-out
If dragged out into following steps? (For electroless plating process) 26 Evaluation by electroless Ni plating deposition Etching Neutralization Catalyzing Activation Electroless Ni Catalyzing Addition amount of etchant (ml/l) 0 1 2 5 10 Mn(Ⅶ) Cr(Ⅵ) Activation Addition amount of etchant (ml/l) 0 0.1 0.2 0.5 1.0 Mn(Ⅶ) Cr(Ⅵ) Electroless Ni Addition amount of etchant (ml/l) 0 0.1 0.2 0.5 1.0 Mn(Ⅶ) Cr(Ⅵ) ( : Overall deposition : Partly un-deposited : Mostly un-deposited) Drag-out of TOP ZECROM ETCHANT will not inhibit deposition same as Cr(Ⅵ)
If dragged out into following steps? (For direct acid copper plating process) 27 Etching Neutralization Conditioner Catalyzing Conductor Acid copper plating Evaluation by direct acid copper plating deposition Addition amount of etchant (ml/l) Conditioner 0 1 2 5 50 Mn(Ⅶ) Cr(Ⅵ) Catalyzing Addition amount of etchant (ml/l) 0 1 2 5 10 Mn(Ⅶ) Cr(Ⅵ) Conductor Addition amount of etchant (ml/l) 0 5 10 20 50 Mn(Ⅶ) Cr(Ⅵ) ( : Overall deposition : Partly un-deposited : Mostly un-deposited) Drag-out of TOP ZECROM ETCHANT will not inhibit deposition same as Cr(Ⅵ)
TOP ZECROM PROCESS 28 Application for single rack system
What is single rack system? 29 Chromic acid etching If operated if not PVC coating No deposit on jigs Deposition on jigs Stainless steel Adsorbed chromium works as poison Plating occurs only on molded resin, No deposition on jigs
Why single rack system? 30 Load Cleaning Etching Neutralization Catalyzing Activation Electroless plating Acid activation Jig stripping Unload Cr plating Micro-porous Ni plating Bright Ni plating Semi-bright Ni plating Acid copper plating Strike plating Single rack system All steps can done by one rack Increase work efficiency, time-saving If deposit occurs on jigs? Increase defective rate Unnecessary deposit on jigs -bad impact on film thickness -widen thickness difference Drops from jigs will attach to molded resin, cause defects in appearances Lower work efficiency, increase work costs Jig change time is necessary Jig stripping time is necessary
How prevent deposition on jigs? (For electroless plating process) 31 Catalyst, electroless Ni Conventional products Catalyst : TOP ZECROM CATALYST Electroless Ni : TOP ZECROM CHEMICAL NICKEL Deposition on jigs Deposition only on resin
How prevent deposition on jigs? (For direct acid copper plating process) 32 PVC coating jig Polyethylene jig Deposition on jigs Deposition only on resin PVC coating materials are under development
TOP ZECROM PROCESS 33 Wastewater Treatment Method
Wastewater treatment for TOP ZECROM ETCHANT 34 Etching Wastewater Treatment Flowchart Recovery 1 Recovery 2 Water rinse Water rinse 1/10 1/100 No.1 No.2 Concentration to original solution Main wastewater tank (containing Cu, Ni) Adjust ph from 7 to 8 Flow from other lines Add flocculants containing Ca, Fe etc. Metal salts : Dispose as sludge Diluted solution: Dilute to satisfy COD or other regulation values
Advantage of TOP ZECROM ETCHANT 35 Comparison after wastewater treatment TOP ZECROM ETCHANT Chromic acid etchant Cu (mg/l) 0.17 0.21 Ni (mg/l) 0.51 0.65 Mn (mg/l) Below detection limit - Cr (mg/l) - Below detection limit TOP ZECROM ETCHANT can be easily treated, eco-friendly product
TOP ZECROM PROCESS: Summary 36 Novel etching process without chromium for molded ABS and ABS/PC resin Use acidic-permanganate base etching solution Continuous operation can be realized by a new stabilizer that can prevent MnO 2 generation Strong plating adhesion : Equal to chromic acid etching Decrease the impact on following steps by drag-out of TOP ZECROM ETCHANT Prevent deposits on jigs, applicable to single rack system Easy wastewater treatment
Operation in mass-production line 37
Plating line in mass-production 38 After etching Etching tank size; 2,300 L (Electrolytic regeneration tank; 550 L)
Plating line in mass-production 39 After electroless Ni plating After acid copper plating Stable operation is ensured
40 Thank you for your attention. Think ECO! ECO! = ECOLOGY 環境 = Environment 創造力 = Creativity 独自性 = Originality