||||IIII US005591354A United States Patent (19) 11 Patent Number: 5,591,354 Patel et al. 45 Date of Patent: Jan. 7, 1997

54 ETCHING PLASTICS WITH NITROSYLS 5,160,600 11/1992 Patel et al...... 427/307 X 5, 180,639 1/1993 Zarnoch ...... 427/307 X 75 Inventors: Gordhanbhai N. Patel, Somerset; 5,211,803 5/1993 Johnson et al. ... 427/307 X Subhash H. Patel, Hoboken, both of Primary Examiner-Thi Dang N.J. Attorney, Agent, or Firm-Omri M. Behr, Esq. 73 Assignee: JP Laboratories, Inc., Middlesex, N.J. 57 ABSTRACT There is disclosed a process of etching the surface of (21) Appl. No.: 327,237 polymeric materials made of polymers having at least one (22 Filed: Oct. 21, 1994 oxidatively degradable functionality which comprises treat

(51] Int. Cl...... B29C 71/00 etchanting said groupsurface consisting with a solution of nitronium, of at least nitrosonium one member ions of and the 52 U.S. Cl...... 216/83; 427/307; 252/79.2 complexes thereof, in a solvent containing less than 40% by 58) Field of Search ...... 216/83; 427/307, weight of water and nitroacidium ions and complexes 427/306; 252/79.2 thereof. The process further comprises use of cosolvents and swellants. It also includes pre and post etching steps directed 56) References Cited to the preparation of the surface for etching and removal of U.S. PATENT DOCUMENTS the etchant respectively. 4,532,015 7/1985 Boultinghouse et al...... 427/306 X 50 Claims, No Drawings 5,591,354 1 2 ETCHING PLASTICS WITH NITROSYLS compounds, such as 1,3-dienes (Chem. Ber. 99,556 (1966). NO" is also capable of halogen abstraction from alkyl BACKGROUND OF THE INVENTION halides G. A. Olah et al, Synthesis, 274 (1979) and 713 (1983)). NO" is an mild oxidizing agent. It is a powerful one 1. Field of the Invention 5 electron oxidant Lee et al, Inorg. Chem., 29, 4196 (1990) This invention relates to a process of etching plastics for and Kim et al., J. Amer: Chem. Soc., 113, 4962 (1991) and painting and plating. The etched plastics can be plated with is therefore used as an oxidative dopant for polymers. It has conventional plating processes. The etched plastics can also been used to oxidatively cleave oximes, hydrazones, thioket be painted with water based paints. als, ethers etc. to their corresponding carbonyl compounds 2. Brief Description of Prior Art 10 Synthesis, 418 (1977), 273 (1979), 609 and 610 (1976), J. Plastics have been metallized/plated for decorative and Org. Chem, 42, 309 (1977). The NO" is electrophilic, and functional (e.g., EMI shielding) purposes. Several plastics, therefore reacts with a large number of basic molecules. The such as copolymers of acrylonitrile, butadiene and styrene nitrosonium cation also forms adducts with crown ethers. (referred herein as to ABS), alloys of ABS (e.g., an alloy of Though the reactions of NSA have been reported with a ABS and polycarbonate), polycarbonate, polyvinyls, such as 15 number of small molecules, there is no report on its reactions polyvinylchloride, polyolefins, such as polybutadiene, poly with polymers, especially for etching and chemical modifi epoxide, polyphenylene sulfide, and polyphenylene oxide cation of the polymers. have heretofore been etched with chromic acid for metalli zation. Chromic acid is highly toxic, expensive, and creates SUMMARY OF THE INVENTION sludge. There is a need for formulations and processes which 20 There is disclosed a process of etching the surface of are less toxic, less polluting, and less expensive for etching polymeric materials made of polymers having at least one plastics for plating and painting. oxidatively degradable functionality which comprises treat A number of substitutes have been proposed for chromic ing said surface with a solution of at least one member of the acid for etching plastics, such as ABS, polyamides, polyes etchant group consisting of nitronium ion (NO) and ters, polyepoxy resins, polyimides and polyvinylchloride for 25 nitrosonium ion (NO), and complexes thereof in a solvent, plating. They include bases, such as NaOH (U.S. Pat. Nos. the solution containing the foregoing should contain less 3,554,880; 3,770,528; 3,791,848; 4,131,698; 4,422,907; than 40% by weight of water. Nitroacidium ions (HNO" 4,505,786; 4,528,245; 4,592,852; 4,629,636; 4,725,504; and complexes thereof may also be used, however the 4,803,097; 4,820,553; 4,832,799; and 4,959,121), NaOCl amount of water present therewith is not limited. (U.S. Pat. Nos. 3,460,897; 4,592,852 and 4,629,636), hydro 30 The solvent may comprise at least one member of the gen peroxide (U.S. Pat. No. 4,645,573), nitric acid (U.S. Pat. group consisting of mineral acids, and aliphatic and aro Nos. 3,471.320; 4.959,121; 5,198,096 and 5,160,600), phos matic carboxylic and sulfonic acids. The solvent addition phoric acid, acetic acid and chromic acid (U.S. Pat. Nos. ally may further comprises a cosolvent or a swellant. While 3,484.270 and 3,522,073), molybdic acid (U.S. Pat. Nos. the materials used in each of these categories may be the 3,563,163 and 3,567,532), potassium permanganate (U.S. 35 same, their purpose may differ. Pat. Nos. 3,598,630; 3,652,351; 3,819,394, 4,042,729; Suitably, the cosolvent or swellant may be selected from 4,073,740, 4,859,300; 4.959,121 and 5,112,513), and sulfur the group consisting of organic acids, sulfoxides, ethers, trioxide (U.S. Pat. Nos. 4,298,636; 4,520,046 and 4,556, sulfolane, halocarbons, haloalkanols and haloalkanoic acids, 587). hetero linear and cyclic-compounds containing oxygen, and Prior to etching plastics for electroless plating, they are 40 hydrocarbons. sometimes pre-treated with a solvent system to swell the The amount of swellant required may be reduced by surfaces. Solvent pretreated/swollen surfaces are micro carrying out the process in the presence of a concentrated toughened and hence are relatively easy to etch and hence aqueous solution of least polluting and least toxic com provide better adhesion of the plated metals. A number of 45 pounds such as an alkali metal salt or alkaline earth metal solvents, such as butyrolactone, propylene carbonate, gly salt. mes, and methanol, have been proposed in a number of patents (e.g., U.S. Pat. Nos. 3,445,350; 3,689.303; 3,769, The process may additionally comprise a pre-etch step in 061; 3,795,622; 3,963,590; 4,063,004; 4,131,698; 4,775, which the surface of the polymer is pretreatment with 449; 5,019,425; 5,132,191; 5,178,956; 5,180,639; and sulfuric acid containing from about 25 to about 85 wt.% of 5,185,185). However, in order to get improved adhesion, the 50 sulfuric acid in the presence of 0 to 10 wt.% of nitric acid solvent must be removed from the surface and the surface or silver nitrate, or this step may comprise swelling the still requires etching. There is a need for an etching formu polymer prior to etching. lation which simultaneously swells the surface. The pre-etch step may also contain a swellant compatible with the acidic pre-etch medium. Nitrosyl sulfuric acid, HO(O=)S(=O)CNO or 55 NOHSO-), which is also known as nitrosyl sulfate, As stated above, the etchant solution which contains a chamber crystals, nitrososulfuric acid, nitroxysulfuric acid, cosolvent may additionally comprise swellant for the poly nitrosulfonic acid, nitrosyl hydrogen sulfate, nitro acid her, sulfite, and nitrose is mainly used for preparing azo deriva The etching process may not only be preceded by, a tives of aromatic amines (e.g. U.S. Pat. No. 5,162,511). 60 pretreatment step but may also be followed by postetching Nitrosyl sulfuric acid is referred to herein as NSA. Solid step, or indeed both may be used. In the post treatment step, NSA decomposes at 73° C. NSA decomposes with forma there is used a similar concentration of sulfuric acid as in the tion of HNO and HSO upon exposure to moisture. It is pre-etch step alone, or with agents capable of oxidizing soluble in sulfuric acid and decomposes violently upon nitronium, nitrosonium or nitroacidium ions-or a combina addition of water. 65 tion of both. NSA is known to react as a nitrosyl cation or nitrosonium The polymers which are etchable in the manner discussed cation (NO) with other nucleophiles including unsaturated above include ABS, polyanhydrides, polycarboxylesters, 5,591,354 3 4 polysulphonic esters, unsaturated polyolefins, polyepoxides, hexachloroantimonate, nitrosonium halides, nitrosonium polycarbonates, polyamides, polyesters, polyacrylates, ther nitrate, nitrosonium phosphate, nitrosonium carboxylates, mosets, polyurethanes, polyepoxys, halopolymers, copoly nitrosonium perchlorate, NOPF, NOPF, metal nitrosyls, mers and alloys of such polymers. nitrosyl halides, nitrosyl acetate, nitrosyl sulfate, nitrosyl Where the polymers are selected from the group consist sulfuric anhydride and mixtures thereof, most suitably ing of polystyrene, polyvinylchloride, polyethylene and nitrosyl Sulfuric acid. The solvent suitably comprises at least one member of the polypropylene a swellant should be used either as a pre group consisting of mineral acids, and aliphatic and aro treatment or it should be present in the etching bath. matic carboxylic and sulfonic acids, preferably sulfuric acid, The etching procedures discussed herein will provide a nitric acid, hydrochloric acid, phosphoric acid, acetic acid, water wettable surface which will give suitable levels of 10 propionic acid, benzoic acid, methanesulphonic acid, ben adhesion for painting with water and oil based paints as well Zenesulphonic acid or trifluoromethane sulphonic acid, most as for electroless plating. suitably the solvent comprises sulfuric acid. As a variant of the foregoing procedure, a substantially a The etching process can be accelerated by a co-etchant or non platable (or paintable) surface may be made capable of catalyst. A small quantity of silver nitrate and nitric acid being plated by electroless plating (or painting) by preparing 15 accelerate/catalyze the etching. Concentration of co-etchant/ an emulsion solution of a polymer such as a copolymer of catalyst required for etching depends upon the concentra acrylonitrile, butadiene and styrene, in a solvent such as a tions of NSA and the solvent and the time-temperature of mixture of acetonitrile and poly(ethylene glycol) diacetate, etching. Preferably the concentration of catalyst/co-etchant coating this emulsion on said non platable surface, drying is 0.01 to 10 wt.%. Most preferably the concentration is 0.2 the surface and then subjecting it to the process or processes 20 to 2 wt.%. discussed herein. Where the solvent additionally comprises a cosolvent and a swellant or where the cosolvent itself is a swellant for the Thereafter the thus prepared surface is subjected to the polymer, it is preferred for it to be selected from the group steps of washing to remove the etching agent therefrom and consisting of C1-C5 alkanoic acids, C1-C5 alkyl-, phenylo then painting with a water based paint or plating with 25 and C1-C5 alkylphenyl-sulfonic acids, diphenyl and di(C1 electroless nickel or electroless copper. C5 alkyl)phenyl ethers, poly(C2-C5 alkylene glycol) di(C1 As a further embodiment, prior to etching, the pretreat C5 alkyl)ethers, C4-C6 cycloalkylethers, polyhalo C1-C5 ment step may comprise a preliminary step of swelling the alkanols, polyhalo C1-C5 alkanoic acids, trihalosulfonic surface of the polymer with swellant therefor. acids, polyhalobenzenes and polyhalo C1-C5 alkyl ben Such swellants include organic acids, nitrocompounds, 30 Zenes, C7-C12 alkyl- and aryl-and alkaryl hydrocarbons. amides, esters, carbonates, sulfoxides, ethers, ketones, Sul Most suitably the cosolvent or swellant may be acetic acid, folane, halocarbons, haloalkanols and haloalkanoic acids, propionic acid, methane- or benzene sulfonic acids, diphenyl hetero linear and cyclic-compounds containing oxygen, and ether, tri(ethylene glycol) dimethyl ether, tetrahydrofuran, hydrocarbons. trichloroethanol, trichloroacetic acid, trichlorosulfonic acid, Where desired, the amount of swellant required is reduced 35 dichlorobenzene, octane, toluene or xylene. by carrying out the process in the presence of an aqueous It has been found that the amount of swellant required is solution of an alkali metal hydroxide or a concentrated reduced by carrying out the process in the presence of a aqueous solution of an alkali metal or alkaline earth metal concentrated aqueous solution and inorganic, organic water salt. soluble compounds such as an alkali metal salt or alkaline 40 DESCRIPTION OF THE PREFERRED EMBODI earth metal salt. MENTS Suitably, the process is carried out in a temperature range The polymers which may be etched by the process of the of from about 10° to about 90° C., preferably in a tempera present invention include polyanhydrides, polycarboxylest ture range of from about 20° to about 50° C. a time range of from about 5 to about 15 minutes. ers, polysulphonic esters, unsaturated polyolefins, polyep 45 oxides, polycarbonates, polyamides, polyesters, polyacry Where the process of the present invention additionally lates, thermosets, polyurethanes, polyepoxys, halopolymers comprises a pre-etching step in which the surface of the and copolymers and alloys of such polymers. Specifically polymer is pretreated with sulfuric acid, which may addi included are copolymers of acrylonitrile, butadiene and tionally comprise a swellant for the polymer, the swellant styrene, and alloys thereof with polycarbonate; polycarbon 50 useable is selected from the same group of materials as listed ate, polybutadiene, polyepoxide, polyphenylene sulfide, above. Similarly, the amount of swellant required may be polycaprolactone, nylon 6 and 66, polyethylene terephtha reduced by carrying out the process in the presence of a late, cellulose acetate, polyvinylacetate, polymethyl concentrated aqueous solution of an alkali metal or alkaline methacrylate, phenolformaldehyde resin, polyphenylene earth metal salt. oxide, polyurea, polyurethane, SMC (sheet molding com 55 The main objectives of the pretreatment by pre-etching pound), polyvinylbutyral, polyacrylonitrile, polychloro are: (1) to minimize dilution of the etching bath, (2) prevent prene, copolymers and alloys of said polymers. Also decomposition of NSA, and (3) partially etch and/or swell included are polystyrene, polyvinyl-chloride, polyethylene the plastic. Pre-etching is not an absolutely essential step. and polypropylene. These latter polymers however must be However, pre-etched samples usually have higher adhesion preswollen prior to etching. 60 of the plated metals. A formulation which significantly does In the process of etching the surface of polymeric mate not affect the etching formulation and minimizes the drag-in rials made of polymers having at least one oxidatively of water for the NSA-etching system, can be used as a degradable functionality, the etchant the solution may con pre-etching formulation. It is also preferred that the pre tain between 1 and 80% by weight of at least one member etching treatment does a partial etching. Partially etched of the etchant group, suitably selected from the group 65 parts are easier to etch with the etching system. consisting of nitrosy sulfuric acid, nitrosonium tetrafluo In a further embodiment, the pre-etch step may be carried roborate, nitrosonium hexafluorophosphate, nitrosonium out in the absence of acid as including a swelling step. 5,591,354 5 6 Where this mode is employed, the swellant may be any of painted with waterborne paints. The adhesion of waterborne those listed above which are usable in the presence of acid paints was excellent. or at least one member of the group consisting of C1-C5 alkyl-amides, -pyrrolidones, and di(C1-C5 alkyl) -ketones, Plastics, being lighter, corrosion resistant, strong and -formamides and sulfoxides, C1-C5 alkyl C1-C5 alkanoates, durable, have been replacing metals in finished products at poly(C2-C5 alkylene glycol), C1-C5 alkanoates and cyclic an increasing rate, especially, in automobile, business C2-C5 alkylene carbonates. Most suitably, this additional machine and other industries. A broad range of engineering swellants may be N-methyl pyrrolidone, dimethylforma thermoplastics and thermosets, such as SMC (sheetmolding mide, 2-butanone, ethyl acetate, triethylene glycol, ethyl compound), polyurea, polyurethane, polypropylene, poly carbonate, butyrolactone, or propylene carbonate. ethylene, polyphenylene oxide, polycarbonate, ABS, nylon, Again, in this mode, the amount of swellant required may O polyvinylchloride, phenolics, and a host of others are used in be reduced by carrying out the process in the presence of an cars. A variety of paints are used to coat plastics. They aqueous solution of an alkali metal hydroxide as well as, as include acrylics, alkyd, epoxies, polyesters, vinyls, olefins, previously a concentrated aqueous solution of an alkali and polyurethanes paints. Solvent borne paints contain about metal salt or alkaline earth metal salt. 40-70% volatile organic liquids. These organic liquids 15 evaporate when the paint is coated on a substrate. These The pretreatment steps are suitably carried out in a volatiles create two major problems: (1) they pollute the temperature range of from about 10 to about 90° C., and in atmosphere and (2) they affect the physical properties of a time range of from about 2 to about 15 minutes. plastics. NSA produces brown fumes when the etched parts are Plastics have hydrophobic surfaces. Most waterborne rinsed with water. Hence, it is preferred that etched parts are 20 rinsed with a solvent/solution which minimizes the fumes paints do not bond well with plastics unless they contain and does not reduce the subsequent adhesion of the metals proper additives and some organic solvents. There is a need for surface treatment of plastics which could make the and paints. The parts etched with NSA solution can be surface accept all kinds of waterborne paints and provides a post-treated with a base or oxidant solution for neutraliza strong bond between the paint and the surface. The surfaces tion/oxidation of the acids. 25 of plastics can be made hydrophilic and micro-roughened by Where a post etching step is employed, and this may be etching, so that they can accept waterborne paints and done whether or not the etching step has been preceded by provide satisfactory adhesion. The hydrophilic groups will a pre-etching step, the oxidants may be at least one member make the surface wettable with water and hence waterborne selected from the group consisting of potassium permanga paints will wet the surface and will spread uniformly on the nate, halogens, ferric salts, metal chlorates, bromates, 30 surfaces. The hydrophilic groups will also help in providing iodates, hypochlorates, hydrogen peroxide, manganese better adhesion by interaction with ionic and polar groups dioxide and nitric acid, most suitably, nitric acid and hydro (e.g., -OH, -NH, -CONH, -CONH-, -COOH, gen peroxide. -O, -CO-, etc.) of the paints. The post etching step is suitably carried out in a tempera The process of the present invention permits regular and ture range of from about 20 to about 60° C. and in a time 35 irregular shaped, nonplatable, conductors and nonconduc range of from about 1 to about 10 minutes. tors, to be plated if they are coated with etchable polymers It is preferred that only one bath each is used for the such as ABS, etched with the NSA system, followed by pre-etching, etching and post-etching steps. However, more plating electroless nickel. Once metallized, the parts can be than one bath of pre-etching, etching and post-etching plated with other metals. An emulsion, suitably of ABS is solutions can be used for proper etching. For example, one 40 coated on a variety of substrates including conductors and can use two pre-etching baths; the first one having 60% nonconductors. The coated parts were etched and plated sulfuric acid followed by 75% sulfuric acid and two post using the formulation and procedures of the present inven etching baths; the first one having 75% sulfuric acid fol tion. Similarly, conductors and non-conductors can be met lowed by 50% sulfuric acid. allized. Though the parts were coated and plated the parts Plastic parts can be rinsed with water after pre-etching 45 completely, by partial/selected coating, one can achieve, and etching treatments. However, the preferred process is partial/selective metallization. The etching can also be done not to rinse parts after the pre-etching and etching treat with other etching systems, e.g., chromic acid. ments. Rinsing plastic parts after pre-etching and etching NSA etches unsaturated polymers, such as polybutadiene causes pollution due to the generation of brown fumes. It is 50 much faster than other polymers. If the polymers, such as preferred that pre-etched parts be directly immersed in the polybutadiene and ABS which are easy to etch are coated on etching bath and etched parts be directly immersed in the any substrate, they can be etched and plated. Emulsions of post-etching bath. The rinse may contain a base and/or ABS were prepared by dissolving platable grade ABS (EP) oxidant to neutralize or decompose the acids. in some representative solvents, such as acetone, ethylac A wetter/surfactant is suitably added in the etching for 55 etate, acetonitrile, chloroform, dichlorobenzene, ethylene mulations to increase the rate of reaction at the surface of the glycol diacetate, propylene carbonate, Xylene, and butyro plastics. The wetter should be stable in etching bath and lactone. The solutions were milky and hence referred hereto should make the plastic parts wettable with the pre-etching, as emulsions. A solvent which wets and/or swells the sub etching and post-etching formulations. Fluorocarbon surfac strate and evaporates within reasonable time (e.g., 10 min tants having -SOH and N' functionalities are preferred 60 utes at room temperature or proportionally lower time at wetters. Fluorochemical surfactants sold, for example, under higher temperatures) is preferred. One can use a mixture of trade names of Zonyls (E. I. du Pont de Nemours and solvents. Company), Fluorad (3M company) and Fora?ac (Atochem) Flat and irregular shaped pieces of plastics, ceramics, can be used as wetters. rocks, metals, wood and glass were coated with the emulsion Plastics are nonwettable with water and hence they are 65 of ABS. The coated parts etched and plated using the generally painted with solvent borne paints. The process of formulations and the procedures of the present invention. the present invention permits plastics etched with NSA be Though the parts were plated with electroless nickel and 5,591,354 7 8 electrolytic copper, they can also be plated with other In accordance with the above procedure, but where, in metals. place of nitrosyl sulfuric acid as etchant, there is used Though the concept was demonstrated with emulsion of nitrosonium tetrafluoroborate, nitrosoniumhexafluorophos ABS, emulsion/solution/dispersion of other etchable poly phate, nitrosoniumhexachloro-antimonate, nitrosonium mers/plastics can also be used. The prefer polymers are halides, nitrosonium nitrate, nitrosonium phosphate, nitroso unsaturated polymers such as ABS and polybutadiene. The nium carboxylates, nitrosonium perchlorate, NOPF, NOPF, most preferred polymer for the coating is platable grade metal nitrosyls, nitrosyl halides, nitrosyl acetate, nitrosy ABS. The emulsions/solutions/dispersions can either be sulfate, nitrosyl sulfuric anhydride and mixtures thereof a made by direct polymerization or by dissolving/dispersing similar result is obtained. the polymers in a suitable solvent. The adhesion of the plated 10 In accordance with the above procedure, but where, in metals depends upon (1) polymer for coating, (2) the solvent place of sulfuric acid there is used as the solvent in etching and (3) substrate. For acceptable bonding with the substrate, step A, at least one member of the group consisting of it is preferred that a proper solvent/polymer be selected. nitric acid, hydrochloric acid, phosphoric acid, acetic acid, Coating of the etchable polymers can be done by a variety propionic acid, benzoic acid, methanesulphonic acid, ben of coating techniques, including selective coating, e.g., 15 Zenesulphonic acid and trifluoromethane sulphonic acid a brush, immersion, spraying, electrostatic spraying, elec similar result is obtained. trodeposition, lamination, calendering, painting, in-mold, gravure, blade, reverse roll, slot, air knife, off-set, extrusion EXAMPLE 2 and curtain coating. 20 Etching with NSA solution only: EXAMPLES Plaques of ABS (EP and EPB) were cleaned with a detergent solution, rinsed with water and etched with the EXAMPLE 1 following NSA solution: Sulfuric acid: 350 grams Etching and plating of ABS: 25 Water: 90 grams NSA (solid): 50 grams Plaques of ABS (EP, EPB and EPBM grades made by Wetter: 2.5 m of 820 LF General Electric Co., Schenectady, N.Y.) were cleaned with Temperature: 30° C. a detergent solution, rinsed with water and etched with the Time: 6 minutes following etching system: 30 The etched parts were rinsed with water for three minutes A Pre-etching: at room temperature. When the etched parts went into water, Sulfuric acid: 750 grams brown fumes were emitted. The parts were then plated with Water: 250 grams electroless nickel and electrolytic copper using commer Nitric acid (70%): 12 ml cially available formulations and procedures described in Wetter: 5 ml of 820 LF (Enthone Inc., West Haven, Conn.) 35 Temperature: 50° C. Example 1 of U.S. Pat. No. 5,160,600. The parts were then Time: 8 minutes annealed at 60° C. for an hour. The peel strength for EP was B Etching 1.2 kg/cm and 0.7 kg/cm for EPB. Sulfuric acid: 700 grams In accordance with the above procedure, but where, in Water: 180grams 40 place of nitrosyl sulfuric acid as etchant, there is used Nitric acid (70%): 2.5 ml nitrosonium tetrafluoroborate, nitrosoniumhexafluorophos NSA (solid): 120 grams phate, nitrosoniumhexachloro-antimonate, nitrosonium Wetter: 5 m of 820 LF halides, nitrosonium nitrate, nitrosonium phosphate, nitroso Temperature: 30° C. nium carboxylates, nitrosonium perchlorate, NOPF, NOPF, Time: 5 minutes 45 metal nitrosyls, nitrosyl halides, nitrosyl acetate, nitrosyl IC) Post-treatment sulfate, nitrosyl sulfuric anhydride and mixtures thereof a Sulfuric acid: 650 grams similar result is obtained. Water: 350 grams EXAMPLE 3 Wetter: 5 m of 820 LF Temperature: 30° C. 50 Etching without post-etching: Time: 3 minutes The etched parts were rinsed with water and then plated Plaques of ABS (EP and EPB) were cleaned with a with electroless nickel using commercially available formu detergent solution, rinsed with water and etched with the lations and procedures described in Example 1 of U.S. Pat. following solutions: No. 5,160,600. The parts were then plated with electrolytic 55 A Pre-etching: copper, annealed at 60° C. for an hour and peel strength was Sulfuric acid: 750 grams determined using a spring scale. The peel strength for EP Water: 250 grams was 2 kg/cm and 1.5 kg/cm for EPB and EPBM. Wetter: 5 ml of 820LF (Enthone Inc., West Haven, Conn.) In accordance with the above procedure, but where, in Temperature: 50° C. place of ABS there is utilized polycarbonate, polybutadiene, 60 Time: 1 minutes polyepoxide, polyphenylene sulfide, polycaprolactone, B Etching nylon 6 and 66, polyethylene terephthalate, cellulose Sulfuric acid: 350 grams acetate, polyvinylacetate, polymethyl-methacrylate, phenol Water: 90 grams formaldehyde resin, polyphenylene oxide, polyurea, poly NSA (solid): 50 grams urethane, SMC (sheet molding compound), polyvinylbu 65 Wetter: 2.5 m of 820 LF tyral, polyacrylonitrile, or polychloroprene a similar result is Temperature: 30° C. obtained. Time: 6 minutes 5,591,354 9 10 The etched parts were rinsed with water for three minutes Temperature: 30° C. at room temperature. When the etched parts went into water, Time: 3 minutes brown fumes were emitted. The parts were then plated with The etched parts were rinsed with water and then plated electroless nickel and electrolytic copper using commer with electroless nickel and electrolytic copper using com cially available formulations and procedures described in mercially available formulations and procedures described Example 1 of U.S. Pat. No. 5,160,600. The parts were then in Example 1 of U.S. Pat. No. 5,160,600. The parts were then annealed at 60° C. for an hour. The peel strength for EP annealed at 60° C. for an hour. The peel strength for EP was and EPB was 2 kg/cm. 1.5 kg/cm and 0.7 kg/cm for EPB. In accordance with the above procedure, but where, in place of sulfuric acid there is used in the post etching bath, EXAMPLE 4 10 potassium permanganate, halogens, ferric salts, metal chlo rates, bromates, iodates hypochlorates, hydrogen peroxide, Etching without pre-etching: manganese dioxide or nitric acid, a similar result is obtained. Plaques of ABS (EP and EPB) were cleaned with a detergent solution, rinsed with water and etched with the EXAMPLE 6 following solutions: 5 A Etching Propylene carbonate (PC) as swellant Sulfuric acid: 350 grams Plaques of ABS (EP and EPB) were cleaned with a Water: 90 grams detergent solution, rinsed with water and etched with the NSA (solid): 50 grams following etching system: Wetter: 2.5 m of 820 LF 20 A Swelling of ABS: Temperature: 30° C. Saturated NaCl Solution: 1000 ml Time: 6 minutes PC: 25 ml B. Post-treatment Temperature: 60° C. Sulfuric acid: 650 grams Time: 3 minutes Water: 350 grams 25 Water Rinse: 3 minutes at room temperature Wetter: 5 ml of 820 LF In accordance with the above procedure, but where in Temperature: 30° C. place of saturated aqueous sodium chloride, there is utilized Time: 3 minutes 10% aqueous sodium hydroxide or 50% aqueous calcium The etched parts were rinsed with water for three minutes chloride solution, the amount of swellant required is simi at room temperature. The parts were then plated with 30 larly reduced. electroless nickel and electrolytic copper using commer B Etching: cially available formulations and procedures described in Sulfuric acid: 350 grams Example 1 of U.S. Pat. No. 5,160,600. The parts were then Water: 90 grams annealed at 60° C. for an hour. The peel strength for EP was NSA (solid): 50 grams 1.7 kg/cm and 0.7 kg/cm for EPB. 35 Wetter: 2.5 ml of 820 LF In accordance with the above procedure, but where, in Temperature: 30° C. place of sulfuric acid there is used as the solvent in etching Time: 3 minutes step A), at least one member of the group consisting of C. Post-treatment nitric acid, hydrochloric acid, phosphoric acid, acetic acid, Sulfuric acid: 650 grams propionic acid, benzoic acid, methanesulphonic acid, ben Water: 350 grams Zenesulphonic acid and trifluoromethane sulphonic acid a Wetter: 5 ml of 820 LF similar result is obtained. Temperature: 30° C. Time: 3 minutes EXAMPLE 5 The etched parts were rinsed with water and then plated 45 with electroless nickel and electrolytic copper using com Benzene sulfonic acid (BSA) as swellant in the mercially available formulations and procedures described pre-etching bath in Example 1 of U.S. Pat. No. 5,160,600. The parts were Plaques of ABS (EP and EPB) were cleaned with a then annealed at 60° C. for an hour. The peel strength for EP detergent solution, rinsed with water and etched with the and EPB was 1.5 kg/cm. following etching system: 50 In accordance with the above procedure, but where, as A Pre-etching: swellant in the pre treatment bath, in place of propylene Sulfuric acid: 750 grams carbonate there is used acetic acid, propionic acid, meth Water: 250 grams anesulfonic acid, diphenyl ether, ethylene glycol dimethyl Wetter: 5 ml of 820 LF (Enthone Inc., West Haven, Conn.) ether, tetrahydrofuran, trichloroethanol, trichloroacetic acid, BSA: 50 grams trichlorosulfonic acid, trichlorobenzene, octane, toluene, Temperature: 0° C. 55 xylene, N-methyl pyrrolidone, dimethylformamide, 2-bu Time: 5 minutes tanone, ethyl acetate, ethylene glycol, butyrolactone or ethyl B Etching: carbonate, a similar result is obtained. Sulfuric acid: 350 grams Water: 90 grams EXAMPLE 7 NSA (solid): 50 grams 60 Wetter: 2.5 ml of 820 LF Painting of etched ABS: Temperature: 30° C. Plaques of ABS were etched with the etching system of Time: 6 minutes Example 1. Etched parts, while still slightly moist were C. Post-treatment painted by dip-coating and/or airspray technique with a Sulfuric acid: 650 grams 65 polyacrylic latex paint made by Red Devil, polyurethane oil Water: 350 grams enamel by Red Devil, and a water based automotive paint Wetter: 5 ml of 820 LF from Du Pont (#408R49912). The painted plaques were first 5,591,354 11 12 allowed to dry at room temperature for 10 minutes followed In accordance with the above procedure, but where in by drying at 60° C. for 2-10 hours. Etched parts were dried place of ABS, the plastic painted is an engineering thermo and painted with a solvent borne paint (polyurethane oil) and plastic or and thermoset, such as SMC (sheet molding dried. The adhesion of the paints was tested with the compound), polyurea, polyurethane, polypropylene, cross-Hatch test (ASTM Method D-3359). The plaques polyphenylene oxide, nylon, polyvinylchloride, phenolics a similar result is obtained. passed the crosshatch test. We claim: In accordance with the above procedure, but where in 1. A process of etching the surface of polymeric materials place of ABS, the plastic painted is an engineering thermo made of polymers having at least one oxidatively degradable plastic or and thermoset, such as SMC (sheet molding functionality which comprises treating said surface with a compound), polyurea, polyurethane, polypropylene, poly 10 solution of at least one member of the etchant group con ethylene, poly-phenyleneoxide, polycarbonate, nylon, poly sisting of nitronium, nitrosonium ions and complexes vinylchloride, phenolics a similar result is obtained. thereof, in a solvent containing less than 40% by weight of Similar results are obtained where the paints used are water and nitroacidium ions and complexes thereof. alkyd, epoxy, polyester, vinyl and olefins paints. 2. A process of claim 1 wherein the solution contains 15 between 1 to 40% by weight of at least one member of the EXAMPLE 8 etchant group. 3. The process of claim 2 wherein the solvent comprises Emulsion of ABS: at least one member of the group consisting of mineral acids, 250 grams of plaques of platable grade ABS (i.e., EP) and aliphatic and aromatic carboxylic and sulfonic acids. were cut into small pieces. The pieces were added in a 1000 20 4. The process of claim 3 wherein the solvent comprises ml beaker containing 450 ml acetonitrile and 150 ml of at least one member of the group consisting of sulfuric acid, ethylene glycol diacetate under vigorous stirring. The mix nitric acid, hydrochloric acid, phosphoric acid, acetic acid, ture was stirred overnight. A milky white emulsion of ABS propionic acid, benzoic acid, methanesulphonic acid, ben was obtained. Zenesulphonic acid and trifluoromethane sulphonic acid. In accordance with the above procedure, but where in 25 5. The process of claim 2 wherein the solvent comprises place of ABS, the plastic emulsified is a polyurea, polyure sulfuric acid. thane, polyisoprene, polycarbonate, polyepoxide, polycar 6. The process of claim 2 wherein the solvent additionally boxyl ester, polyamide, polyacrylate, halopolymer or their comprises a cosolvent. copolymers or alloys a similar result is obtained. 7. The process of claim 6 wherein the cosolvent is a 30 swellant for the polymer. 8. The process of claim 1 wherein the cosolventis selected EXAMPLE 9 from the group consisting of organic acids, sulfoxides, ethers, sulfolane, halocarbons, haloalkanols and haloal Solution of Polybutadiene kanoic acids, hetero linear and cyclic-compounds containing 35 oxygen, and hydrocarbons. A solution of 6.5gm of polybutadiene was dissolved in 65 9. The process of claim 8 wherein the cosolventis selected ml of cyclohexane. A clear solution was obtained which was from the group consisting of C1-C5 alkanoic acids, C1-C5 coated on a plaque of polystyrene and a wood chip and alkyl-, phenyl- and C1-C5 alkyl-phenylsulfonic acids, allowed to dry for one hour at room temperature. The coated diphenyl and di(C1-C5 alkyl)phenyl ethers, C2-C5 alkylene parts were then etched and plated with electroless nickel 40 glycol di(C1-C5 alkyl)ethers, C4-C6 cycloalkylethers, poly using the formulations and the procedures of Example 1. halo C1-C5 alkanols, polyhalo C1-C5 alkanoic acids, triha The adhesion of electroless nickel was excellent. losulfonic acids, polyhalobenzenes and polyhalo C1-C5 In accordance with the above procedure, but where in alkylbenzenes, C7-C12 alkyl- and aryl- and alkaryl hydro place of polybutadiene the plastic dissolved is a polyurea, carbons. polyurethane, polyisoprene, polycarbonate, polyepoxide, 45 10. The process of claim8 wherein the swellantis selected polycarboxyl ester, polyamide, polyacrylate, halopolymer or from the group consisting of acetic acid, propionic acid, their copolymers or alloys a similar result is obtained. methane- and benzene sulfonic acids, diphenyl ether, ethyl ene glycol dimethyl ether, tetrahydrofuran, trichloroethanol, EXAMPLE 10 trichloroacetic acid, trichlorosulfonic acid, trichloroben 50 Zene, octane, toluene and Xylene. Metallization of Conductors and Nonconductors: 11. The process of claim 8 wherein the amount of swellant Flat and irregular shaped pieces of nonplatable grade required is reduced by carrying out the process in the ABS, polystyrene, polyethylene, polycarbonate (poly presence of a concentrated aqueous solution of an alkali bisphenol-A carbonate), polymethylmethacrylate, glass, metal or alkaline earth metal salt. rock, aluminum, cardboard, and carved wood were mounted 55 12. The process of claim 1 which is carried out in a on stainless steel racks and coated either by brushing or temperature range of from about 10 to about 90° C. spraying the emulsion of Example 8. The coated parts were 13. The process of claim 1 which is carried out in a dried in air for about 10 minutes at room temperature temperature range of from about 20° to about 50° C. followed by drying in an oven at 70° C. for five hours. The 14. The process of claim 12 which is carried out in a time emulsion dried to a clear coat of about 1-2 mil (25-50 60 range of from about 5 to about 15 minutes. micrometer). The ABS coated parts were not wettable with 15. The process of claim 1 additionally comprising a water. The coated parts were then etched and plated with pretreatment step in which the surface of the polymer is electroless nickel followed by electrolytic copper using the pretreated with sulfuric acid containing from about 25 to formulations and the procedures of Example 1. All parts about 85 wt.% of sulfuric acid in the presence of 0 to 10 wt. became wettable with water after the etching. All parts 65 % of nitric acid. plated with excellent adhesion of electroless nickel and 16. The process of claim 15 additionally comprising a electrolytic copper. swellant for the polymer. 5,591,354 13 14 17. The process of claim 16 wherein the amount of 33. The process of claim 1 wherein the polymers are swellant required is reduced by carrying out the process in selected from the group consisting of polyanhydrides, poly the presence of a concentrated aqueous solution of an alkali carboxylesters, polysulphonic esters, unsaturated polyole metal salt or alkaline earth metal salt. fins, polyepoxides, polycarbonates, polyamides, polyesters, 18. The process of claim 16 wherein the swellant is polyacrylates, thermosets, polyurethanes, polyepoxys, halo selected from the group consisting of organic acids, sulfox polymers and alloys of such polymers. ides, ethers, sulfolane, halocarbons, haloalkanols and haloal 34. The process of claim 1 wherein the polymers are kanoic acids, heterolinear and cyclic-compounds containing selected from the group consisting of copolymers of acry oxygen, and hydrocarbons. lonitrile, butadiene and styrene, and alloys thereof with 19. The process of claim 18 wherein the swellant is polycarbonate; polycarbonate, polybutadiene, polyepoxide, selected from the group consisting of C1-C5 alkanoic acids, 10 polyphenylene sulfide, polycaprolactone, nylon 6 and 66, C1-C5 alkyl-, phenyl- and C1-C5 alkyl-phenylsulfonic polyethylene terephthalate, cellulose acetate, polyvinylac acids, diphenyl and di(C1-C5 alkyl)phenyl ethers, C2-C5 etate, polymethylmethacrylate, phenol-formaldehyde resin, alkylene glycol di(C1-C5 alkyl)ethers, C4-C6 cycloalky polyphenylene oxide, polyurea, polyurethane, SMC (sheet lethers, polyhalo C1-C5 alkanols, polyhalo C1-C5 alkanoic molding compound), polyvinylbutyral, polyacrylonitrile, acids, trihalosulfonic acids, polyhalobenzenes and poly-halo 15 polychloroprene and alloys of said polymers. C1-C5 alkyl benzenes, C7-C12 alkyl- and aryl-and alkaryl 35. The process of claim 13 wherein the polymers are hydrocarbons. selected from the group consisting of polystyrene, polyvi 20. The process of claim 19 wherein the swellant is nylchloride, polyethylene and polypropylene. selected from the group consisting of acetic acid, propionic 36. The process of claim 1 of etching the surface of acid, methane- and benzene sulfonic acids, diphenyl ether, 20 polymeric materials made of polymers having at least one ethylene glycol dimethyl ether, tetrahydrofuran, trichloroet oxidatively degradable functionality to provide a water hanol, trichloroacetic acid, trichlorosulfonic acid, trichlo wettable surface capable of being painted with a water based robenzene, octane, toluene and xylene. paint to provide a painted layer having a satisfactory level of 21. The process of claim 15 which is carried out in a adhesion to said surface which comprises treating said temperature range of from about 10 to about 90° C. 25 surface with a solution of at least one member of the etchant 22. The process of claim 15 which is carried out in a time group consisting of nitrosonium, nitronium ions and com range of from about 2 to about 15 minutes. plexes thereof, in a solvent containing less than 40% by 23. The process of claim 1 additionally comprising a weight of water and nitroacidium ions and complexes postetching step in which the surface of the polymer is thereof. posttreated with at least one member of the group consisting 30 37. The process of claim 1 of etching the surface of of sulfuric acid containing from about 25 to about 80 wt.% polymeric materials made of polymers having at least one of sulfuric acid and agents capable of oxidizing nitronium, oxidatively degradable functionality to provide a water nitrosonium or nitroacidium ions. wettable surface capable of being plated with electroless 24. The process of claim 23 wherein the oxidizing agent nickel or electroless copper to provide a plated layer having is at least one member selected from the group consisting of 35 a satisfactory level of adhesion to said surface which com potassium permanganate, halogens, ferric salts, metal chlo prises treating said surface with a solution of at least one rates, bromates, iodates and hypochlorates, hydrogen per member of the etchant group consisting of nitrosonium, oxide, manganese dioxide and nitric acid. nitronium ions and complexes thereof, in a solvent contain 25. The process of claim 15 additionally comprising a ing less than 40% by weight of water and nitroacidium ions postetching step in which the surface of the polymer is 40 and complexes thereof. posttreated with at least one member of the group consisting 38. A process of preparing substantially a non platable of sulfuric acid containing from about 25 to about 80 wt.% polymeric surface to make it capable of being plated by of sulfuric acid and agents capable of oxidizing nitronium, electroless plating which comprises the steps of: nitrosonium or nitroacidium ions. i) preparing an emulsion of a copolymer of acrylonitrile, 26. The process of claim 25 wherein the oxidizing agent 45 is at least one member selected from the group consisting of butadiene and styrene, in a mixture of acetonitrile and potassium permanganate, halogens, ferric salts, metal chlo ethylene glycol diacetate, rates, bromates, iodates and hypochlorates, hydrogen per ii) coating said emulsion on said non platable surface, oxide, manganese dioxide and nitric acid. iii) drying said emulsion to provide an etchable surface, 27. The process of claim 23 which is carried out in a 50 iv) subjecting said etchable surface to the process of claim temperature range of from about 20° to about 60° C. 1. 28. The process of claim 23 which is carried out in a time 39. The process of claim 36 additionally comprising the range of from about 1 to about 10 minutes. steps of: 29. The process of claim 25 which is carried out in a a) washing said surface to remove the etching agent temperature range of from about 20° to about 60° C. 55 therefrom, 30. The process of claim 25 which is carried out in a time range of from about 1 to about 10 minutes. b) painting said surface with a water based paint. 31. The process of claim 1 wherein the etchant group is 40. The process of claim 37 additionally comprising the selected from the group consisting of nitrosyl sulfuric acid, steps of: nitrosonium tetrafluoroborate, nitrosonium hexafluorophos 60 a) washing said surface to remove the etching agent phate, nitrosonium hexachloroantimonate, nitrosonium therefrom, halides, nitrosonium nitrate, nitrosonium phosphate, nitroso b) plating said surface with electroless nickel or electro nium carboxylates, nitrosonium perchlorate, NOPF, NOPF, less copper. metal nitrosyls, nitrosyl halides, nitrosyl acetate, nitrosyl 41. The process of claim 38 additionally comprising the sulfate, nitrosyl sulfuric anhydride and mixtures thereof. 65 steps of: 32. The process of claim 1 wherein the etchant group v) washing said surface to remove the etching agent comprises nitrosyl sulfuric acid. therefrom, 5,591,354 16 vi) painting said surface with a water based paint. dimethylformamide, 2-butanone, ethyl acetate, ethylene gly 42. The process of claim 32 additionally comprising the col, ethyl carbonate and propylene carbonate. steps of: 47. The process of claim 43 wherein the amount of v) washing said surface to remove the etching agent swellant required is reduced by carrying out the process in therefrom, the presence of an aqueous solution of an alkali metal vi) plating said surface with electroless nickel or electro hydroxide or a concentrated aqueous solution of an alkali less copper. metal or alkaline earth metal salt. 43. The process of claim 1 additionally comprising a prior 48. A process of etching the surface of polymeric mate swelling step in which the surface of the polymer is pre rials made of polymers having at least one oxidatively treated with swellant therefor. O degradable functionality, which method comprises 44. The process of claim 4 wherein the swellant is selected pretreating said polymer surface with a composition com from the group consisting of organic acids, nitrocompounds, prising sulfuric acid containing from about 25 to about amides, esters, carbonates, sulfoxides, ethers, ketones, sul 85 wt.% of sulfuric acid in the presence of 0 to 10 wt. folane, halocarbons, haloalkanols and haloalkanoic acids, % of nitric acid, a swellant for the polymer, and a hetero linear and cyclic-compounds containing oxygen, and 15 concentrated aqueous solution of an alkali metal salt or hydrocarbons. alkaline earth metal salt; and 45. The process of claim 44 wherein the swellant is treating said surface with a solution of at least one selected from the group consisting of C1-C5 alkanoic acids, member of the etchant group consisting of nitronium, C1-C5 alkyl-, phenyl- and C1-C5 alkyl-phenyl-sulfonic nitrosonium ions and complexes thereof. acids, diphenyl and di(C1-C5 alkyl)phenyl ethers, C2-C5 20 49. The process of claim 48 where said solvent contains alkylene glycol di(C1-C5 alkyl)ethers, C4-C6 cycloalky less than 40% by weight of water and nitroacidium ions and lethers, polyhalo C1-C5 alkanols, polyhalo C1-C5 alkanoic complexes thereof. acids, trihalosulfonic acids, polyhalobenzenes and poly-halo 50. The process of etching the surface of polymeric C1-C5 alkylbenzenes, C7-C12 alkyl- and aryl- and alkaryl materials made of polymers having at least one oxidatively hydrocarbons, C1-C5 alkyl-amides, -pyrrollidones, and 25 degradable functionality to provide a water wettable surface di(C1-C5 alkyl) -ketones,-formamides and -sulfoxides, capable of being painted with a water based paint to provide C1-C5 alkyl C1-C5 alkanoates, C2-C5 alkylene glycol a painted layer having a satisfactory level of adhesion to said C1-C5 alkanoates and cyclic C2-C5 alkylene carbonates. surface, said process comprising treating said surface with a 46. The process of claim 45 wherein the swellant is solution of at least one member of the etchant group con selected from the group consisting of acetic acid, propionic 30 sisting of nitrosonium, nitronium ions and complexes acid, methane- and benzene sulfonic acids, diphenyl ether, thereof, in a solvent containing less than 40% by weight of ethylene glycol dimethyl ether, tetrahydrofuran, trichloroet water and nitroacidium ions and complexes thereof. hanol, trichloroacetic acid, trichlorosulfonic acid, trichlo robenzene, octane, toluene, xylene, N-methyl pyrrollidone, ck k : k :