DE1569434A1 - Process for modifying plastic surfaces for subsequent electroplating - Google Patents

Description

Process for the `modification of plastic surfaces for the following, end.e electroplating: un The invention relates to a V: e.rfahren -zur-iodfizerurs, of Plastic surfaces for fine subsequent etroal ° ose l4ietall- abs he_dung with subsequent 'electroplating: 13Isher: e = demands you for -his- Galvariisi.erunö -d.-r K # unet- fabrics necessary: di @ e, -iaftfestel4etsllbekeim, ung a m @ edhansach @ e Aufrauhun @ der Ob.erl «äch: e., .Z. 13 .. mitt-: ells -Ncaßatrahll ° äppen: s resp. : frorr @ el-s: cheuerts ,. Complicated gea;: ri tzte; # e ,, T: open , blown blown , f, # b or in some other way: st.elllte .f # orlnt @ e cannot do this _glnch'äßi.g -nufderauht; are: and are then only inadequate to continue to coat. Ixi many cases is .dis, mechanical A: ufrauhuug "LB on .. injected parts, except for not allowed big and @ later on: Ialv @ anis @ chem ways not to level out anymore @iesc: Methods # require :(, a great deal of time and effort Plit bl # shcr known items for roughening or roughening The surface of the plastic material swells due to chemical factors , also takes place ° a. to .st; .mark on, rff to the With only a short chemical treatment: only an insufficient de HaftfeBtigket, der naehtrlglivh @ abge # svhieden "enIetallsh-eht achieved:.' Before ull.em: but 'the b @ ebekannt_g, eword.enen: ehe.n; s: chexl Solutions the large Nsa.cht-eil "only: one, @: ewe.ils limited -An- reversibility on a plastic be: st i = th cons titute Lon to own ": for example:. vo-rz; uga @ r @ nee only, on lis.chpolymerisate of Styr: o1y But: ed: -en and Acry n :: 1arl o: d: Gr only on foly-2; 2-bs- hydr: oxyphenylpropane-carb.onatj, but would be desirable = one ch.em: s # ch., e activationgsldssun, .mit: broad application, $ m'ögli @ ehket hinsi-chtl: ch. About veTschle: denßten plastic type: en .. .Fs wuxd: e now a procedure for .I # .o: d @ .fzs @ ecn -, the surfaces , of "'K-inserts ,, which all OII BZndung iakti" fouraende groups i; t a - # ': J ! a, e rubs # 1 #; ennz.ni: # t 1- : #ribt navhftol @ ,. en.de found, ";#ef.en;, c # am c1a @ 1u .. = rtcl xtclx @ ,. e #; ennz.ni:#rib is that the plastic surfaces are treated with a solution of '. @ as: erstoffperoxid or peroxides in concentrated sulfuric acid, which can also contain water. Plastics which have substituents that are definitely activating the CH bond are those with aryl groups and olefinic groups, such as vinyl groups in particular. This group of plastics includes polymers, copolymers and block copolymers made from, for example, styrene, butadiene, isoprene, chlorobutadiene or acrylic compounds, as well as phenolic and paxyd resins. Polystyrene, copolymers of styrene and acrylonitrile or of styrene, butadiene and acrylonitrile, for example, have achieved great economic importance. Plastics that also contain sufficient activating groups for the CH bond are also those that are interrupted by heteroatoms within the C main valence chains, for example polyacetals, polyethers, linear polyesters, unsaturated polyester resins, urea and melamine resins, polyamides, polyurethane and polyureas . Less activating groups or groups that activate only at a higher temperature are methyl, chlorine and nitrile groups. Polypropylene, polyvinyl chloride and polyacrylonitrile are therefore not suitable for the process according to the invention. The oxygen-containing groups are introduced by immersing the shaped bodies to be treated in a bath of concentrated sulfuric acid and aqueous hydrogen peroxide or peroxides. A particular embodiment of the method according to the invention is characterized in that the concentration of pure peroxide, based on the total bath liquid, is between 0.05% by volume and 6% by volume, preferably between 0.1 and 2% by volume and that the concentration of pure sulfuric acid, depending on the total bath liquidity, is between 45 and 96% by volume, preferably between 80 and 96% by volume.

The remainder of the bath fluid can be water. Immersion takes place preferably at room temperature, * although the temperature of the bath liquid or the molded body to be immersed can in principle be very variable, e.g. B. If necessary, the moldings can be preheated to 1000 ° C. For maximum durability of the sulfuric acid peroxide baths, the lowest possible temperature is naturally favorable. At room temperature, however, the baths have a shelf life of several days.

The duration of thawing, the concentration of sulfuric acid or Peroxide and the temperature of the bath or the shaped body during dipping can be adjusted accordingly the desired degree of activation of the surface or according to the above Auszeführten constitution of the plastic and thus its activation against the peroxidic attack are largely optimally coordinated ...

For example, in the case of a non-polymerizate of tyrol, butadiene, and acrylonitrile, a quantity of 5% by volume of a 30% by weight aqueous hydrogen peroxide solution in 98 % by weight sulfuric acid at room temperature already shows good results for a dipping time of just 2 minutes . To achieve the same effect on a mixed polymer of styrene / acrylonitrile, 3 minutes immersion time is required, on a polystyrene 5 minutes immersion time, on a Poly-4f: 5 - 7 minutes immersion time.

For plastics that are quickly attacked by concentrated sulfuric acid It is naturally favorable to lower and lower the sulfuric acid concentration to increase the ferric oxide concentration. In general, the Peroxyä concentration with a ventilated 'plastic type the immersion time can be increased, while the immersion time can be shortened when the temperature is increased. As' P:, roxyd-e for the "use of parts of:" Hydrogen peroxides are, for example, alkali peroxides, Ammonium dipersulfate or organic peroxides or hydroperoxides or peroxysäureri, such as x. B. Peroxyessiz; säurt, geüi,; net.

It was surprising that there was already a relative short thawing time of the molded plastic body in the solutions of the invention Procedure, sufficient modification of the solid surface with oxygen-containing Groups causes, since so far peroxidic reactions on polymers only in Lbsuni; are described. In general, immersion times of a few solids are sufficient Minutes.

After the treatment of the plastic parts according to the invention These processes are rinsed and can either be done in a well-known way with metal salt baths further treated or otherwise modified for the purpose of a later electroplating will.

It is Z. B. possible, a plastic part treated according to the invention after rinsing with water in a solution of 1 - 10 kg of tin (II) chloride and 5 1 hydrochloric acid (D. 1,1.9) in 7.00 1 aqueous G, total solution 1 - 5 min. to dive, to rinse in Y: a'sser, then in a solution of 0.5 kg of silver nitrate and 1. 1 ammonia (D. 0.9) to be immersed in 100 liters of total aqueous solution for 1/2 - 2 minutes, again in water to rinse and then in a known copper plating solution for chemical production a conductive copper layer for 5 - 20 minutes.

The method according to the invention has the advantage that the surface of the molded plastic parts is only roughened to such an extent that that in the optimal case the very thin, currentless, in the top copper layer applied as described I g layer starch shows a good metallic luster effect: therefore only small additional thicknesses of copper, nickel or chrome are necessary to create decorative effects. The alvanic refinement takes place in a known manner. The achieved adhesive strength of the Schicitcz @ corresponds at least to the adhesive strength according to the mechanical roughening process with less effort and time expenditure.

The following examples serve to illustrate the process according to the invention. After the treatment described in each case in the sulfuric acid peroxide bath, all parts were further treated as follows: brief rinsing in water, immersion for 5 minutes in a solution of 3 kg of tin (II) chloride and 5 liters of hydrochloric acid `( D, 1.19) in 100 l of total aqueous solution, brief rinsing in Aasger, 1 1.1, m. dive into. a solution of. 0.5 kg of silver nitrate and 1 liter of ammonia (D. 0, g) in 100, 0 1 total aqueous solution.

brief rinsing in water. The parts treated in this way can immediately be chemically copper-plated in the usual 1 "ice. For example:, iel 1., Ili copolyuierisat from; tyrol and l = crylni cril, as it ulitur the: l * art" :: drawing (, iri Luran as injection "ußmusse is commercially available, was treated with: a) conc.; I": eic acid and 1.25 vol. -1j, e-, ner Periiy.irollösun "; (30 GAY, j @), temperature: . 25o C, Tauchjeit: 5: - in a, b conc) sulfuric acid and 5 vol .- o a rerhydrollösung (30 wt,), temperature: 250 C, immersion time: 3 min Bei, iel 2 r a... Copolymer of styrene, butadiene and acrylonitrile, as it is commercially available under the trademark Novodur or Cycolac, was mixed with concentrated sulfuric acid and 5% by volume of a perhydrol solution (30% by weight), temperature: 250 ° C., immersion time : 2 1,1.in .. Example 3 Polystyrene, as it is commercially available under the name Polystyrene III D, was treated with: ü) concentrated chirefic acid and 5% by volume perhydrol solution (30 wt ), Temperature: 25o C, immersion time: 5 min., B) conc. Sulfuric acid and 20% by volume perhydrol solution (30% by weight), temperature: 25o C, immersion time: 12_ min., C) conc. Sulfuric acid and 5 parts by weight N ammonium peroxydisulfate, temperature: 250 C, immersion time: 10 min. Example 4 Poly-z formalderiydacetal> as it is available under the trademark Delrin commercially, was acidified with conc sulfuric acid and 5 vol .. Perhydrolösunü (30 wt .-%), temperature: 250 C, immersion time: 7 min. Treated. Example 5 polyamide. @ .; t as it is commercially available under deui @@ arc: nzeichen Ultramid l1, Iconz. Sulfuric acid and 5 vol: -% of a 15rew. Current aqueous hydrogen peroxide solution, temperature: 250C, immersion time: 1 1/2 liters. treated.

Claims (1)

P ä Tentana p r ü che 1. A process for modifying the surfaces of Kunatstoffen ,, having the C-H bond activating groups by introducing oxygen-containing groups for subsequent electroplating, characterized in that the plastic surfaces date with a solution of hydrogen peroxide or of peroxides is treated in concentrated sulfuric acid, which can also contain it. 2.) The method according to claim 1, characterized in that the concentration of pure peroxide, .bezoaen on the total bath liquid, between 0.05 vol .-% and 6 Vo1.T @, preferably between 0.1 and 2 vol .-> , * 'q and that the concentration of pure sulfuric acid, based on the total bath liquid, is between 45 and 96% by volume q, preferably between 80 and 96% by volume.