U.S. patent application number 13/578315 was filed with the patent office on 2012-12-06 for method for metallising objects which have at least two different plastics on the surface.
This patent application is currently assigned to ATOTECH DEUTSCHLAND GMBH. Invention is credited to Heinz Ewald, Arnaldo Pereira.
Application Number | 20120305406 13/578315 |
Document ID | / |
Family ID | 42270001 |
Filed Date | 2012-12-06 |
United States Patent
Application |
20120305406 |
Kind Code |
A1 |
Pereira; Arnaldo ; et
al. |
December 6, 2012 |
Method for Metallising Objects Which Have at Least Two Different
Plastics on the Surface
Abstract
The following method is to improve selectivity during
metallisation of surface areas to be metallised on objects 7 having
different plastics while not allowing the areas not to be
metallised to be metallised: A) etching of the objects 7 with an
etching solution; B) treatment of the objects 7 with a solution of
a colloid or with a metal compound, the metal being a metal of
Group VIIIB or IB of the Periodic Table of the Elements; and C)
electrolytic metallisation of the objects 7 with a metallisation
solution. The objects 7 are subjected to ultrasonic treatment
during the treatment in a further method step following method step
B) and before method step C) in order to avoid metallisation of at
least one first plastic exposed on the surface of the objects 7
while at least one second plastic exposed on the surface of the
objects 7 is metallised.
Inventors: |
Pereira; Arnaldo; (Berlin,
DE) ; Ewald; Heinz; (Korschenbroich, DE) |
Assignee: |
ATOTECH DEUTSCHLAND GMBH
Berlin
DE
|
Family ID: |
42270001 |
Appl. No.: |
13/578315 |
Filed: |
February 7, 2011 |
PCT Filed: |
February 7, 2011 |
PCT NO: |
PCT/EP2011/051757 |
371 Date: |
August 28, 2012 |
Current U.S.
Class: |
205/164 |
Current CPC
Class: |
C23C 18/30 20130101;
C25D 5/20 20130101; C23C 18/1653 20130101; C25D 5/56 20130101; C25D
5/022 20130101; C23C 18/405 20130101; C23C 18/1607 20130101; C23C
18/2086 20130101; C23C 18/36 20130101 |
Class at
Publication: |
205/164 |
International
Class: |
C25D 5/56 20060101
C25D005/56 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 12, 2010 |
EP |
10001464.6 |
Claims
1. A method for metallising objects which have at least two
different plastics on the surface, comprising the following method
steps: A) Etching of the objects with an etching solution; B)
Treating the objects with a solution of a colloid or with a
solution of a metal compound, the metal being a metal of Group
VIIIB or IB of the Periodic Table of the Elements; C)
Electrolytically metallising the objects with a metallisation
solution, the method further comprising subjecting the objects to
ultrasonic treatment during a treatment in an additional method
step performed after performing method step B) and before method
step C), not however in electroless depositing of metal, to avoid
metallisation of at least one first plastic exposed on the surface
of the objects while at least one second plastic exposed on the
surface of the objects is metallised.
2. The method according to claim 1, wherein the second plastic is a
plastic selected from the group comprising an
acrylnitrile-butadiene-styrol copolymer (ABS copolymer), a
polyamide, and a mixture of an ABS copolymer with at least one
polymer which is different to the ABS copolymer.
3. The method according to claim 2, wherein the at least one other
polymer which is different to the ABS polymer is a
polycarbonate.
4. The method according to claim 2, wherein the first plastic is a
polycarbonate or a covering lacquer used to prevent metallisation
of the object.
5. The method according to claim 1, further comprising at least one
of the following further method steps between method steps B) and
C): Ba1) Rinsing the objects in a rinsing solution; Bb1) Treating
the objects in an accelerating solution or a reducing agent
solution; Bc1) Rinsing the objects in a rinsing solution; Bd1)
Electroless metallising the objects in an metallisation solution;
and Be1) Rinsing the objects in a rinsing solution.
6. The method according to claim 5, further comprising subjecting
the objects to ultrasonic treatment during treatment in at least
one of the method steps Ba1), Bb1), Bc1), Be1).
7. The method according to claim 1, further comprising at least one
of the following further method steps between method steps B) and
C): Ba2) Rinsing the objects in a rinsing solution; Bb2) Treating
the objects in a conversion solution so that an sufficiently
electrically conductive layer is formed on the surface of the
objects for direct electrolytic metallisation; and Bc2) Rinsing the
objects in a rinsing solution.
8. The method according to claim 7, further comprising subjecting
the objects to ultrasonic treatment during treatment in at least
one of the method steps Ba2), Bb2), Bc2).
9. The method according to claim 1, further comprising immersing
the objects in treatment tanks containing the respective solutions
to execute the method steps and providing at least one ultrasound
emitter in the respective solution in the treatment tank in which
an ultrasonic treatment is carried out to expose the objects to
ultrasound.
10. The method according to claim 9, further comprising arranging
the ultrasound emitter on one side of the objects and arranging an
ultrasound reflector or a further ultrasound emitter on the other
side of the objects.
11. The method according to claim 1, wherein the etching solution
is a chromic acid/sulfuric acid solution.
12. The method according to claim 1, wherein the solution of the
colloid is an activator solution comprising a palladium/tin
colloid.
13. The method according to claim 3, wherein the first plastic is a
polycarbonate or a covering lacquer used to prevent metallisation
of the object.
Description
[0001] The present invention is based on a conventional method for
metallising objects which have at least two different plastics on
the surface. According to the conventional method the objects are
A) etched with an etching solution, B) treated with a solution of a
colloid or with a solution of a metal compound, the metal being a
metal of Group VIIIB or IB of the Periodic Table of the Elements,
and C) metallised electrolytically using a metallising
solution.
[0002] Plastic objects can be metallised using an electroless
metallising method or alternatively by using a direct plating
method. The object is first cleaned and etched in both methods and
then treated with a noble metal and finally metallised. The etching
is normally undertaken using chromic acid/sulfuric acid. Etching
solutions made on the basis of organic solvents or an alkaline or
acid permanganate solution can be used as an alternative for
certain plastics. The etching serves to make the surface of the
object more accommodating for the subsequent metallisation so that
the surfaces of the objects can be wetted well with the respective
solutions in the following treatment steps and the deposited metal
is adequately firmly bound to the surface. To etch the surface made
out of acrylnitrile-butadiene-styrol-copolymer (ABS copolymer), it
is etched using chromic acid/sulfuric acid in such a way that
surface microcaverns are formed in which metal precipitates and
subsequently firmly adheres to the surface there. Once the etching
is completed the plastic is activated for electroless metallisation
using an activator which contains a noble metal and then
electrolessly metallised. A thicker metal layer can then also be
applied electrolytically afterwards. In the case of the direct
plating method that gets by without using electroless
metallisation, the etched surface is usually treated with a
palladium colloid solution and then with an alkaline solution which
contains copper ions forming a complex with a complexing agent.
Thereafter the object can then be electrolytically metallised
directly (EP 1 054 081 B1).
[0003] In an alternative embodiment for a direct plating method
according to U.S. Pat. No. 4,590,115, a plastic object is
manufactured which contains small electrically non-conductive oxide
particles of a non-noble metal, for example copper, in the polymer.
The oxide particles exposed on the surface of the object are
reduced to a metal using a reducing agent such as a boron hydride.
The object can then be coated electrolytically with metal
immediately afterwards or at a later point in time. This document
indicates a copper(I) oxide containing object being put in a water
bath to be cleaned by the action of ultrasound. The copper(I) oxide
in the object is then subsequently reduced to copper using sodium
borohydride so that electrolytic copper can be deposited later on
the surface of the object.
[0004] The influence of ultrasonic irradiation on the kinetics of
formation, structure and hardness of electroless nickel deposits is
described in M. Y. Abyaneh et al. "Effects of Ultrasonic
Irradiation on the Kinetics of Formation, Structure and Hardness of
Electroless Nickel Deposits", J. Electrochem. Soc., 154 (9),
D467-D472 (2007). Accordingly, the deposition rate of nickel on the
steel plate for use of ultrasound in an electroless nickel
deposition bath can be significantly increased.
[0005] The plastic parts to be metallised are usually manufactured
using an injection moulding method. If plastic parts made out of
two or more different plastics are manufactured in order to obtain
different surface characteristics then they can be manufactured
using a so-called multiple injection method. In this process a
first plastic is injected into an injection mould and then a second
plastic is injected into an injection mould having an altered form
and which contains the object being produced in the injection
method. Correspondingly, objects made out of three different
plastics can be manufactured in an appropriate way.
[0006] The requirements upon the pretreatment of the plastic for
decorative electroplating of objects made out of plastic or those
containing plastic are generally increasing all of the time. A
colloidal activator made on a palladium basis is normally used in
the case of plastic metallisation. When using this activator,
faults in the surface of the object arising from the injection
moulding method are covered and therefore concealed. However,
objects made in such a way can fail in a subsequent temperature
testing method or only after the object is already in its final
place of use and, for example, is installed in a device, since it
may turn out that the metal layers deposited after activation do
not sufficiently adhere to the substrate.
[0007] There are also particularly high demands in the case of
selective plastic metallisation where the objects to be treated are
made from at least two different plastics in order to achieve
metallisation of only one part of the surface of the object while
the other part of the surface remains unmetallised.
[0008] Therefore, activators are normally used which are specially
equipped, depending on the respective requirements, concerning
their composition or the operating parameters required for their
use. A maximum coverage of the surfaces of the object with
palladium or alternatively an optimal selectivity of the different
regions of the surface of the object can be set using such
activators. If different objects are manufactured in a
metallisation plant, a number of containers for the different
activators and optionally additional rinsing tanks have to be
available, so that altogether a rather extensive plant technology
is required as well as a complex plant control system and
logistics.
[0009] The same applies for the acceleration step required for
conventional electroless metallisation of objects made out of
plastic which serves to prepare the activated surfaces of the
objects for the subsequent electroless metallisation in a suitable
manner. This means that partly different accelerators are used for
plating objects containing two or three plastics, since these as
well have to be adjusted through adaptation of their composition,
and the optimised operating parameters for their use, to the
selectivity of the metallisation or alternatively also to a maximum
palladium coverage on the plastic substrates. It is also necessary
to have rather extensive plant technology and a complex control
system and logistics in this case.
[0010] Despite the measures mentioned above it turns out that the
metallisation process is not stable so that there are continuous
declines in production with unwanted overgrowths on the surfaces
which selectively are not to be coated with metal while, at the
same time, it is to be ensured that the surfaces to be metallised
are coated flawlessly and without any uncoated areas. It would be
quite possible to totally avoid metal depositing on the surfaces
not to be metallised with the known process. However, in these
cases, it is usually not possible to deposit metal on the surfaces
to be metallised securely and flawlessly, that is, completely and
without uncoated areas. The above-mentioned problems can arise, for
example, through minor deviations in the operating parameters.
These problems can, in some events, lead to high scrap rates with
an average reject rate of 30-50% of the objects.
[0011] Therefore the invention is based on the problem that it has
not been possible until now, with adequate process security, to
achieve selective sharp-edged metallisation of objects on whose
respective surfaces at least two different plastics are exposed to
obtain secure, flawless metallisation on one of the plastics and a
surface which is completely free of deposited metal on the other
plastic. Therefore the object of the invention is to guarantee that
the areas of the surface not to be metallised are completely free
of metal after performing the metallisation step and that the areas
of the surface to be metallised are completely and faultlessly
covered with metal.
[0012] This object is solved through use of the inventive method
according to claim 1. Preferred embodiments are indicated in the
sub-claims.
[0013] As far as a number of objects are mentioned below, and in
the claims, which are treated using the method according to the
invention, either a number of objects are being referred to or,
alternatively, in an appropriate manner, also just respectively one
single object.
[0014] The method according to the present invention is used to
metallise objects which at least partially and preferably
completely consist of plastic, in order to provide particularly at
least one second surface area of the object fully, that is without
any void and without uncoated areas, with a metal layer and to not
metallise at least one first surface area, that is to leave this
part of the plastic surface totally free of metal. The selectivity
of the metallisation is made possible in that there is at least one
first plastic on the surface of the object which is not coated by
the metal at all and a second plastic which is coated with the
metal without any voids. The border between both surface areas has
a sharp edge which means that the surface area coated with the
metal extends exactly along the surface boundary line between the
first surface area and the second surface area.
[0015] For example, the object can partially consist of metal or
another material and partially of the at least two types of
plastic. In a particularly preferred embodiment of the invention
the object fully consists of plastic, the majority of which
primarily consists of one or optionally a plurality of second
plastics which can adherently be metallised and of one or
optionally a plurality of first plastics which cannot adherently be
metallised or which cannot be metallised at all, which means that
this/these plastic(s) completely refuse metal deposition.
Preferably, the object consists of one or a plurality of second
plastics which can adherently be metallised and of one or a
plurality of first plastics which cannot adherently be metallised
and which is/are applied at least on the surface thereof to the
second plastic(s) which can adherently be metallised.
[0016] These types of objects can be used in sanitary areas, in
automobile engineering, as a furniture fitting or closing device,
for operating elements on electrical or electronic devices,
jewellery, spectacles or similar items. Selective metal coating is
preferably used due to the different surface properties of the
object to achieve decorative effects.
[0017] Compared to the conventional methods in which the objects
[0018] A) are first etched with an etching solution; [0019] B) are
then treated with a solution of a colloid or with a compound,
particularly a salt of a metal of Group VIIIB or IB of the Periodic
Table of the Elements (noble metal); and [0020] C) are finally
metallised electrolytically using a metallising solution, they are
additionally subjected to a treatment in a further method step,
being carried out between method steps B) and C) but not during
electroless depositing of metal, by being subjected to ultrasonic
treatment. This avoids metallisation of at least one first plastic
exposed on the surface of the objects while at least one second
plastic exposed on the surface of the objects is metallised.
[0021] Usually, the above-mentioned method steps A), B) and C) do
not necessarily have to be performed immediately one after the
other. Typically, further method steps such as rinsing steps and
optionally further treatment steps are carried out between these
method steps. The object is treated and/or rinsed off in at least
one further method step between method steps B) and C). The
indicated sequence of the method steps A), B) and C) must be
observed, however.
[0022] The exposure of ultrasound on the object is applied during
any one of the method steps being carried out after treatment of
the object with the noble metal colloid solution or with the
solution of the noble metal compound according to method step B)
and before electrolytically metallising the object in method step
C), but not during an electroless metallisation step. For example,
rinsing steps can be considered for this which are normally
executed between both method steps mentioned, B) and C).
[0023] The treatment with ultrasound according to the invention has
the effect that no metal coating is deposited at all on the first
surface areas of the object or a deposited metal coating is
completely removed. In this way the conditions for metallisation on
the second surface areas can be adjusted in such a way that the
metallisation takes place perfectly and without any problems on
these areas, which means that the metallisation conditions do not
have to be adjusted in such a way that metallisation on the second
plastic areas barely takes place in order to ensure that no metal
deposits on the first plastic areas. It is therefore possible to
open up a wider processing window for successful metallisation
without having any metal deposit on the first surface areas. This
guarantees a more secure method management so that faulty
metallised objects are not produced. This also leads to a situation
where the boundary line between the first plastic, which forms the
first surface area of the object, and the second plastic, which
forms the second surface area of the object, is exactly reproduced
by the metallisation boundary so that a sharp-edged selective
metallisation is achieved.
[0024] In a preferred embodiment of the invention a second (to be
metallised) plastic is an acrylnitrile-butadiene-styrol copolymer
(ABS copolymer) or a polyamide or a mixture of an ABS copolymer and
at least one other polymer which is different to the ABS copolymer.
Most preferred, the at least one other polymer is polycarbonate
(PC). It is preferred, for example, to use ABS/PC blends as the
second plastic material.
[0025] In a further preferred embodiment of the invention a first
plastic is a polycarbonate or a covering lacquer (a stop-off
lacquer) used to prevent metallisation of the object. These types
of covering lacquer have served for a long time to selectively
cover surface areas of work pieces which were to be electroplated
in order to avoid depositing of metal in the covered surface areas.
This type of covering lacquer is well known to the person skilled
in the art. Covering lacquers can be any kind of lacquer which
prevent, in particular, metal deposition and also ensure that they
adhere well to the plastic body so that no electroplating liquid
can penetrate at the interface between the covering lacquer and the
plastic body. Prevention of metallisation is, for example, achieved
by adding substances which inhibit electroless metallisation, for
example lead compounds such as lead acetate, lead chloride or
cadmium acetate. For example, covering lacquers are used on the
basis of solutions of tar compounds.
[0026] In a preferred embodiment of the invention at least one of
the following additional method steps are performed between the
method steps B) and C), wherein ultrasonic treatment may be
performed in one or some or a plurality of these method steps:
[0027] Ba1) Rinsing the objects in a rinsing solution; [0028] Bb1)
Treating the objects in an accelerating solution or in a reducing
agent solution; [0029] Bc1) Rinsing the objects in a rinsing
solution; [0030] Bd1) Electroless metallisation of the objects in
an electroless metallisation solution; and [0031] Be1) Rinsing the
objects in a rinsing solution.
[0032] In this preferred embodiment, these further method steps are
carried out when the objects are to be metallised using an
electroless metallisation method which means that a first metal
layer is applied on the objects using an electroless method.
[0033] The method steps Ba1), Bb1), Bc1), Bd1) and Be1) are
performed in the sequence given, but not necessarily immediately
one after the other. For example, a plurality of rinsing steps can
be performed respectively instead of each individual of the rinsing
steps Ba1), Bc1), Be1).
[0034] Most preferably, ultrasonic treatment is performed in method
step Be1), i.e., during the rinsing of the objects after
electroless metallization has been performed. In this case, further
ultrasonic treatment may also be performed in any of the further
method steps Ba1), Bb1) and Bc1).
[0035] The accelerating solution preferably serves to remove
components of the colloid of the colloid solution according to
method step B), for example a protective colloid. If the colloid of
the colloid solution according to method step B) is a palladium/tin
colloid, a solution of an acid is preferably used as an
accelerating solution, for example sulfuric acid, hydrochloric
acid, citric acid or also tetrafluoboric acid, in order to remove
the protective colloid (tin compounds). The reducing agent solution
is used if a solution of a compound of a noble metal is used in
method step B), for example a hydrochloric acid solution of
palladium chloride or an acid solution of a silver salt. The
reducing agent solution in this case is also a hydrochloric acid
solution and, for example, contains tin(II) chloride, or it
contains another reducing agent such as NaH.sub.2PO.sub.2 or a
borane or boron hydride, such as an alkali or earth alkali borane
or dimethylaminoborane.
[0036] In a further preferred embodiment of the invention the
objects are subjected to ultrasonic treatment during at least one
of the method steps Ba1), Bb1), Bc1), Be1) wherein the ultrasonic
treatment can be done, if a number of rinsing steps are performed
instead of just one rinsing step in one or some or in each one of
the respective method steps Ba1), Bc1) or Be1), in one of the
rinsing steps, in some of the rinsing steps or in all of the
rinsing steps, which means that the objects are subjected to
ultrasonic treatment in one of the method steps or a plurality of
the method steps, including the rinsing steps, after treatment with
the colloid solution or with the reducing agent solution, but not,
on the other hand, in the method step in which the objects are
electroless metallised. The reason is that the electroless
metallisation bath would not be stable under the effect of
ultrasound. It is possible that catalytic nuclei deposited on the
surface of the objects are stripped off by the ultrasonic treatment
and, in this way, find their way into the electroless metallisation
bath. They would start unintended electroless depositing of metal
there. It is, however, possible that the ultrasonic treatment is
performed in any one of the method steps following colloid
treatment or following treatment with a reducing agent
solution.
[0037] If, on the other hand, a method is preferred in which the
objects are not metallised electrolessly but are to be directly
metallised using an electrolytic metallisation process (without
electroless metallisation), then at least one of the following
further method steps are performed in this further preferred
embodiment of the invention between method steps B) and C): [0038]
Ba2) Rinsing the objects in a rinsing solution; [0039] Bb2)
Treatment of the objects in a conversion solution so that a
sufficiently electrically conductive layer is formed on the surface
of the objects for direct electrolytic metallisation; and [0040]
Bc2) Rinsing the objects in a rinsing solution.
[0041] The method steps Ba2), Bb2) and Bc2) are performed in the
sequence given, but not necessarily immediately one after the
other. For example, a plurality of rinsing steps can be performed
respectively instead of each individual of the rinsing steps Ba2)
and Bc2).
[0042] The conversion solution preferably serves to create a
sufficiently electrically conductive layer on the surface of the
objects in order to subsequently allow direct electrolytic
metallisation, without preceding electroless metallisation. If the
colloid of the colloid solution according to method step B) is a
palladium/tin colloid then an alkaline solution containing copper
ions complexed with a complexing agent is preferably used as a
conversion solution. For example the conversion solution can
contain an organic complexing agent such as tartaric acid or
ethylenediaminetetraacetic acid and/or one of its salts such as a
copper salt such as copper sulfate.
[0043] In a further preferred embodiment of the invention the
objects are subjected to ultrasonic treatment during at least one
of the method steps Ba2), Bb2), Bc2) wherein the ultrasonic
treatment can be done, when a number of rinsing steps are carried
out instead of one rinsing step in one or some or in each one of
the respective method steps Ba1), Bc1) or Be1), in one of the
rinsing steps, in some of the rinsing steps or in all of these
rinsing steps, which means that the objects are subjected to
ultrasonic treatment in one of the method steps or a plurality of
the method steps, including the rinsing steps, after treatment with
the colloid solution. The ultrasonic treatment can be performed in
any of the method steps after the colloid treatment.
[0044] In order to treat objects with ultrasound in a preferred
embodiment of the invention, to execute the method steps, the
objects are immersed in treatment tanks containing the respective
solutions, with additionally at least one ultrasound emitter being
in the respective solution in the treatment tank, in which an
ultrasonic treatment is carried out, to expose the objects to
ultrasound. Such ultrasound emitters are usually ultrasound
generators and ultrasound resonators made in the form of flat
plates. These generators can be located in a plane in the treatment
tank for efficient ultrasonic treatment which is parallel to the
plane in which the objects to be treated are located or which is
arranged parallel to this plane. If the objects are, for example,
fastened to a rack which has a main plane, the ultrasound generator
can be located parallel to this rack plane in the tank. In this way
it is possible to obtain a treatment as uniformly as possible of
all of the objects fastened to the rack, as the distance between
the ultrasound generator and the objects is always the same.
[0045] In a particularly advantageous embodiment of the invention
the ultrasound emitter is located on one side of the objects. An
additional ultrasound reflector or a further ultrasound emitter can
be located on the other side of the objects. Both, the first
ultrasound emitter and the second ultrasound emitter or,
alternatively, the ultrasound reflector can each have a flat shape.
The ultrasound reflector can, for example, be a metal plate, for
example a stainless steel plate (reflection plate).
[0046] In the above-mentioned embodiments of the invention the
ultrasound emitter(s) for treatment of the objects are immersed in
the solution in which the objects will be treated. The ultrasound
energy in this case is transmitted from the one or more ultrasound
emitters through the solution as the medium to the objects.
[0047] As an alternative, an ultrasound emitter can also transmit
ultrasound energy to the objects via a holder on which the objects
are held, for example a rack. To do this, the ultrasound emitter
can, for example, be placed on a receptacle for holding the rack in
the treatment tank and fastened there so that the ultrasound energy
is transmitted via this receptacle and the holder to the
objects.
[0048] The treatment liquids described below are preferably
aqueous.
[0049] In a preferred embodiment of the invention the etching
solution is a chromic acid I sulfuric acid solution. Such solutions
typically contain 300-400 g/l CrO.sub.3 and 300-400 g/l of conc.
H.sub.2SO.sub.4 in water. Particularly preferred is a solution
which contains CrO.sub.3 in a concentration of 360-400 g/l and a
particularly preferred concentration of 375-385 g/l as well as
H.sub.2SO.sub.4 in a concentration of 360-400 g/l and a
particularly preferred concentration of 375-385 g/l. The chromic
acid/sulfuric acid can also contain a fluorosurfactant to obtain
optimal wetting of the surfaces. The chromic acid/sulfuric acid can
also contain palladium ions, for example in the form of a salt, for
example palladium chloride. The palladium ions can be present in a
concentration of, for example, 5-100 mg/l, particularly preferred
of 7-50 mg/l and most preferred of 10-30 mg/l, based on Pd.sup.2+.
The chromic acid/sulfuric acid is preferably used at a temperature
above room temperature, for example at 30-90.degree. C.,
particularly preferred at 60-80.degree. C. and most preferred at
65-75.degree. C. The treatment time is preferably 5-30 min,
particularly preferred 10-20 min.
[0050] After etching using chromic acid/sulfuric acid it is
preferable to carry out a reduction treatment in a reducing agent
solution, preferably after one, preferably after a plurality of
rinsing steps, for example three, during which the chromium(VI)
ions remaining on the surface of the object are reduced to
chromium(III) ions. It is preferable to use an aqueous solution of
sodium sulfite to do this or a hydroxylammonium salt, for example
the chloride or the sulfate. This solution is also used at a
temperature above room temperature, for example at 30-60.degree.
C., particularly preferred at 40-50.degree. C. The treatment time
is preferably 0.5-5 min, particularly preferred 1-3 min and most
preferred 1.5-2.5 min.
[0051] An alternative to etching in the chromic acid/sulfuric acid
can also be etching in a sodium or potassium permanganate solution.
This solution can be acid or alkaline. To be acidic, it can
particularly contain sulfuric acid, and to be alkaline, it can
particularly contain sodium hydroxide. Potassium permanganate can
be present in a concentration of up to about 70 g/l and sodium
permanganate in a concentration of up to about 250 g/l. The lower
concentration limit of each of these salts is typically 30 g/l. If
the solution is alkaline, it contains 20-80 g/l for example, but
preferably 30-60 g/l NaOH. In this case it can also contain a
fluorosurfactant to improve wetting of the surfaces of the objects.
Further, as in the case of chromic acid/sulfuric acid, it can
contain palladium ions, for example in the form of a palladium
salt, in particular palladium chloride, in a concentration, for
example, of 5-100 mg/l, particularly preferred 7-50 mg/l and most
preferred 10-30 mg/l, based on Pd.sup.2+. The permanganate solution
is preferably used at a temperature above room temperature, for
example at 60-95.degree. C., particularly preferred 80-90.degree.
C. The treatment time is preferably 5-30 min, particularly
preferred 10-20 min.
[0052] After treatment with the permanganate solution the objects
are subjected to reduction treatment in a reducing agent solution,
after rinsing off the excess permanganate solution, in one or a
plurality of, preferably three, rinsing steps, in order to reduce
the permanganate still adhering on the surfaces of the objects to
manganese(II) ions. Preferably, in this case an acid solution of
hydroxylammonium sulfate or chloride is used or an acid solution of
hydrogen peroxide.
[0053] In a preferred embodiment of the invention the solution of
the colloid of the metal of Group VIIIB or IB of the Periodic Table
of the Elements is an activator solution containing a palladium/tin
colloid. This colloid solution preferably contains palladium
chloride, tin(II) chloride and hydrochloric acid or sulfuric acid.
The concentration of the palladium chloride is preferably 5-100
mg/l, particularly preferred 20-50 mg/l and most preferred 30-45
mg/l, based on Pd.sup.2+. The concentration of the tin(II) chloride
is preferably 0.5-10 g/l, particularly preferred 1-5 g/l and most
preferred 2-4 g/l, based on Sn.sup.2+. The concentration of the
hydrochloric acid is preferably 100-300 ml/l (37% by weight of
HCl). Furthermore, a palladium/tin colloid solution also preferably
contains tin(IV) ions which are generated through oxidation of the
tin(II) ions. The temperature of the colloid solution is preferably
20-50.degree. C. and particularly preferred 30-40.degree. C. The
treatment time is preferably 0.5-10 min, particularly preferred 2-5
min and most preferred 3.5-4.5 min.
[0054] As an alternative the colloid solution can also contain
another metal of Group VIIIB or IB of the Periodic Table of the
Elements, for example platinum, iridium, rhodium, gold or silver or
a mixture of these metals. It is basically possible for the colloid
not to be stabilised with tin ions as a protective colloid but
rather another protective colloid being used instead, for example
an organic protective colloid like polyvinyl alcohol.
[0055] If a solution of a noble metal compound is used instead of a
colloid solution, preferably a solution is used which contains an
acid, in particular hydrochloric acid, and a noble metal salt. The
noble metal salt can, for example, be a palladium salt, preferably
palladium chloride, palladium sulfate or palladium acetate, or a
silver salt, for example silver acetate. As an alternative a noble
metal complex can also be used, for example a palladium complex
salt such as a salt of a palladium-aminopyridine complex. The noble
metal compound is present, for example, in a concentration of 40
mg/l to 80 mg/l, based on the noble metal, for example based on
Pd.sup.2+. The solution of the noble metal compound can be used at
25.degree. C. or at a temperature from 25.degree. C. to 70.degree.
C.
[0056] Before bringing the objects in contact with the colloid
solution, the objects are preferably first brought into contact
with a pre-dipping solution which has the same composition as the
colloid solution but without the metal of the colloid and its
protective colloid, which means that this solution, in the case of
a palladium/tin colloid solution, just contains hydrochloric acid
if the colloid solution also contains hydrochloric acid. The
objects are brought directly into contact with the colloid solution
after treatment in the pre-dipping solution, without rinsing off
the objects.
[0057] After treating the objects with the colloid solution these
are typically rinsed and then brought into contact with the
accelerating solution in order to remove the protective colloid
from the surface of the objects.
[0058] If the objects are treated with a solution of a noble metal
compound instead of a colloid solution they will be subjected to a
reduction treatment after first being rinsed. The reducing agent
solution used for these cases contains hydrochloric acid and
tin(II) chloride if the solution of the noble metal compound is a
hydrochloric acid solution of palladium chloride. It is, however,
preferable to use an aqueous solution of NaH.sub.2PO.sub.2.
[0059] For electroless metallisation, the objects can first be
rinsed after the acceleration or treatment with reducing agent
solution and then electrolessly plated with nickel, for example. A
conventional nickel bath will serve to do this which, for example,
contains a number of substances including nickel sulfate, a
hypophosphite, for example sodium hypophosphite, as a reducing
agent, and organic complexing agents and pH adjusting agents (for
example a buffer).
[0060] As an alternative, an electroless copper bath can be used
which typically contains a copper salt, for example copper sulfate
or copper hypophosphite, and also a reducing agent such as
formaldehyde or a hypophosphite salt, for example an alkali or
ammonium salt, or hypophosphorous acid, and also one or more
complexing agents such as tartaric acid, as well as a pH adjusting
agent such as sodium hydroxide.
[0061] Any metal depositing baths can be used for the subsequent
electrolytic metallisation, for example for depositing nickel,
copper, silver, gold, tin, zinc, iron, lead or their alloys. This
type of depositing bath is well known to the person skilled in the
art. A Watts nickel bath is normally used as a bright nickel bath
which contains nickel sulfate, nickel chloride and boric acid as
well as saccharine as an additive. As a bright copper bath a
composition is used which, for example, contains copper sulfate,
sulfuric acid, sodium chloride as well as organic sulfur compounds,
in which the sulfur is present in a low oxidation stage, for
example as an organic sulfide or disulfide, as additives.
[0062] If a direct electroplating process is used, that is, a first
metal layer is not deposited electrolessly but rather after
treatment of the objects with the conversion solution and deposited
electrolytically after the optional subsequent rinsing treatment,
then an electrolytic metallisation bath is used, for example a
nickel strike bath, which is preferably composed on the basis of a
Watts nickel bath. These types of baths for example contain nickel
sulfate, nickel chloride and boric acid and saccharine as an
additive.
[0063] Treatment of the objects according to the method according
to the invention is preferably performed in a conventional dipping
process in which the objects are dipped subsequently in solutions
in containers in which the respective treatment takes place. In
this case the objects can either be fastened to racks or filled
into drums and dipped in the solutions. Fastening to racks is
preferred because a more directed transmission of the ultrasound
energy to the objects is possible via the racks. Alternatively, the
objects can be treated in so-called conveyorized processing plants
in which they lay, for example, on racks and are continuously
transported in a horizontal direction through the plant and treated
with ultrasound, as required.
[0064] The following description of examples shall further
elucidate the invention. The FIGURE shown also serves to further
illustrate the invention. Both the examples and the FIGURE shall
not in any way be construed as limitation of the scope of the
invention being protected.
[0065] FIG. 1: shows a schematic diagram of a treatment tank with
an object to be treated and an ultrasound emitter as well as an
ultrasound reflector.
[0066] FIG. 1 shows a treatment tank 1 which contains a treatment
solution 2 which reaches the liquid level 3 in the treatment tank
1. The treatment liquid 2 can, for example, be a rinsing liquid or
the colloid solution or an accelerating solution or also another
treatment liquid in which the objects are treated according to the
invention with ultrasound. The treatment tank 1 is designed
according to the type of treatment liquid 2 for the respective
treatment to fulfil the required functions in this treatment liquid
2. The treatment tank 1 can, for example, be equipped with a
heater, a filter system, an air injection system, means for moving
the objects, vibrating systems for the objects, circulating pumps,
metering devices and similar items. The suitable design required
for this will be well-known to the person skilled in the art and
will be selected appropriately.
[0067] There are mounts for a goods carrier rod 5 on the upper edge
4 of the treatment tank 1. This goods carrier rod 5 fully extends
over the treatment tank 1. There is a rack 10 hung on the goods
carrier rod 5 over a suspension mounting 6 on which a number of
objects 7 to be treated are fastened. The rack 10 with the objects
7 is located in the middle and parallel to a vertical plane in the
tank 1. There is also an ultrasound emitter 8 located vertically
and parallel to this plane at a distance a from the objects which
is formed in the form of a plate. In this case it is fastened to
the floor and to the side walls of the treatment tank 1. There is a
second ultrasound emitter 9 in the tank also located vertically and
parallel to this plane on the other side of the rack, at a distance
b from the objects. It is, however, possible to use a steel plate
instead of the second ultrasound emitter 9 which reflects the
ultrasound waves emitted by the first ultrasound emitter 8. The
distances a and b preferably are the same. This arrangement allows
for obtaining a very even treatment of the objects 7 on the rack
10.
[0068] The following examples were all performed respectively with
an arrangement involving an ultrasound emitter and an ultrasound
reflector in the form of a steel plate, under the conditions given
in each respective example.
[0069] Different parts were used for performing the following
examples which were manufactured in a double injection process from
ABS and a partial over-injection of the ABS base body with
polycarbonate: a PQ rotary knob, a Start/Stop press-button, a thumb
lever holder as well as a cap with slits.
[0070] The parts mentioned were treated in all experiments
according to the processing sequence described in Tab. 1, the
respective changes being made in the treatment conditions in the
individual examples compared to those given in Tab. 1 and the
ultrasonic treatment being performed variously. The parts were
respectively treated up to metallisation with bright copper for
examining the selectivity of the metallisation that means complete,
flawless metallisation in the areas which were to be metallised and
for examining the total prevention of metallisation in those areas
which were not to be metallised. In order to establish the degree
of perfection an examination was undertaken to see whether the
parts had faulty areas in the regions to be metallised, that is
deficient metallisation (blow throughs, voids) and overgrowths in
the regions which were not to be metallised, that is metallisation
at least in some areas and therefore faulty treatment.
COMPARATIVE EXAMPLE 1
[0071] 9 thumb lever holders and 10 PQ rotary knobs were fastened
to a rack (surface area: 6 dm.sup.2). These parts were treated
according to the method described in Tab. 1 with the following
changes being made: [0072] 8) Activator: 2.times.1 min
(1.times.H/S) [0073] 9) (clean) flow rinsing: 1 min, air injection
[0074] 10) Acceleration: 50.degree. C., 4 min., air injection
[0075] 14) Rinsing twice after electroless nickel coating: air
injection [0076] 17) A nickel strike instead of a copper strike
(Adhemax IC copper): 1 min, 0.5 AJdm.sup.2, up to expiry of 5 min 1
A/dm.sup.2 [0077] 18) Cupracid: 20 min, 3 A/dm.sup.2
[0078] Ultrasound was not used in any of the method steps.
[0079] Results
[0080] There were overgrowths found on all of the areas not to be
metallised in the polycarbonate areas on all 9 thumb lever holders
as well as on 8 of the 18 PQ rotary knobs. Therefore these parts
had to be thrown away as scrap so that 100% of the thumb lever
holders and 44% of the PQ rotary knobs were thrown away as
scrap.
EXAMPLE 2 ACCORDING TO THE INVENTION
[0081] 72 thumb lever holders (with an area of 15 dm.sup.2)
fastened to a complete rack were treated using the process
according to Tab. 1 with the following changes being made: [0082]
8) Activator: 2.times.1 min (1.times.HIS), composition: Pd.sup.2+:
17.4 mg/l, Sn.sup.2+: 1.00 g/l, HCl (37% by weight): 239 ml/l
[0083] 9) (clean) rinsing: 1 min, air injection [0084] 10)
Acceleration: 50.degree. C., 4 min., air injection [0085] 13)
Adhemax Ni LFS: 8 min, 35.degree. C. [0086] 14) Rinsing twice: air
injection [0087] 15) Rinsing while applying ultrasound at the same
time: 4 min, 48.degree. C. [0088] 16) Etching slightly: 0.5 min
[0089] 17) A nickel strike instead of a copper strike (Adhemax IC
copper): 1 min, 0.5 AJdm.sup.2, up to expiry of 5 min 1 A/dm.sup.2
[0090] 17a) Etching slightly: 0.5 min [0091] 18) Cupracid: 20 min,
3 A/dm.sup.2
[0092] Thus ultrasound was used in this case in the rinsing phase
after the electroless depositing of nickel.
[0093] The parts were subsequently rinsed, activated, coated with
bright nickel (10 min) and then coated with chromium (2 min).
[0094] Thus ultrasound was used in a second rinsing tank after the
electroless nickel plating. The frequency of the ultrasound used
was 40 kHz.
[0095] Results
[0096] 71 of the thumb lever holders showed no signs of overgrowths
on them in the areas not to be metallised and voids in the areas to
be metallised. Just one part demonstrated a minimal level of
overgrowth with a width of 1 mm on a stay. Thus 99.5% of all
Start/Stop knobs could be qualified as flawless regarding the
selectivity of metallisation in the areas to be metallised and
prevention of metallisation in the areas not to be metallised.
EXAMPLE 3 ACCORDING TO THE INVENTION
[0097] In one further experiment the method according to the
Example 2 of the invention was used to treat 72 thumb lever holders
fastened to a rack (with a surface of 15 dm.sup.2), but with an
altered activator composition (Pd.sup.2+: 18.9 mg/l, Sn.sup.2+:
1.40 g/l, HCl (37% by weight): 241 ml/l).
[0098] Thus ultrasound was used in this case in a second rinsing
tank after the electroless nickel plating. The frequency of the
ultrasound used was 40 kHz.
Results:
[0099] 71 of the 72 thumb lever holders were flawless which means
that there were no overgrowths in the areas not to be metallised
and no voids in the areas to be metallised, while a blow through
was observed on just one 1 thumb lever holder. Thus 98.5% of all
parts were perfect.
EXAMPLE ACCORDING TO THE INVENTION 4
[0100] 162 PQ rotary knobs (with an area of 30 dm.sup.2) were
fastened to a complete rack and treated under the same conditions
as the Start/Stop knobs from Example 2 of the invention.
[0101] Thus ultrasound was also used in this case in a second
rinsing tank after the electroless nickel plating. The frequency of
the ultrasound used was again 40 kHz.
Results:
[0102] Random sampling producing 60 checked parts delivered a 100%
flawless result regarding the selectivity of metallisation.
[0103] In one further experiment the method according to Example 4
of the invention was used to treat 162 PQ rotary knobs (with a
surface of 30 dm.sup.2) fastened to a rack, but with an altered
activator composition (Pd.sup.2+: 18.9 mg/l, Sn.sup.2+: 1.40 g/l,
HCl (37% by weight): 241 ml/l).
[0104] Thus ultrasound was also used in this case in a second
rinsing tank after the electroless nickel plating. The frequency of
the ultrasound used was again 40 kHz.
Results:
[0105] Random sampling producing 30 checked parts showed that 28
parts, that is 93.4%, were flawless: There were tiny pointlike
voids on the black part in the case of two of the PQ rotary knobs.
However, all areas not to be metallised were totally free of metal
on these parts (no overgrowths). The other 28 parts were flawless
regarding both the absence of metal in the areas not to be
metallised as well as regarding coverage with metal in the areas to
be metallised.
EXAMPLE 6 OF THE INVENTION
[0106] In one further experiment all four articles (PQ rotary
knobs, Start/Stop press-buttons, thumb lever holder and cap with
slits) were fastened to a multiple rack with a surface of 10
dm.sup.2.
[0107] The treatment conditions for the parts were essentially the
same as for the Example 2 of the invention with the following
differences: [0108] 8) Activator: 2.times.2 min [0109] 10)
Acceleration: 3 min, 50.degree. C., air injection [0110] 14)
Rinsing twice: air injection [0111] 15) Rinsing with ultrasound: 3
min
[0112] The parts were not metallised using bright nickel and
chromium.
[0113] Thus ultrasound was also used in this case in a second
rinsing tank after the electroless nickel plating. The frequency of
the ultrasound used was again 40 kHz.
Results:
PQ Rotary Knob:
[0114] 9 parts were flawless while 4 parts demonstrated minimal
overgrowth in the areas not to be metallised: thus 70% of all parts
were flawless;
Start/Stop Press-Button:
[0115] 8 parts were flawless; 2 parts demonstrated blow throughs
which means that 80% of all parts were flawless;
Thumb Lever Holder:
[0116] all 6 parts, that is 100% of all parts were flawless;
Cap with Slits:
[0117] all 10 parts, that is 100% of all parts were flawless.
EXAMPLES 7-18 OF THE INVENTION
[0118] Further experiments were conducted with the above-mentioned
injection-moulded parts as well as with a sleeve, also comprising
an ABS base body which was sprayed over with polycarbonate in a
double injection process on a sleeve edge. The method sequence used
here is shown in Tab. 2.
[0119] Tab. 3 shows the respective underlying conditions for the
individual experiments whereby the respective deviations from these
conditions given in Tab. 2 are listed separately.
[0120] The results of the selective metallisation achieved with
these experiments are shown in Tab. 4.
TABLE-US-00001 TABLE 1 Method Sequence for the Plastic
Metallisation Treatment Temperature period Movement Operation
[.degree. C.] [min] of the liquid 1) Precleaning UniClean 55 2
Circulation 151 2) Rinsing 0.5 3) ABS etching.sup.1) 68 1, then AI,
WB**) 1x H/S*) (10 s), than a further 11 4) Rinsing 0.5 AI**) 5)
Adhemax .RTM. 30 0.5, then Neutralizer Cr.sup.2) 1x H/S*) (10 s),
then a further 0.5 AI**) 6) Rinsing 0.5 AI**) 7) Pre-dipping
solution.sup.3) 25 0.5 AI**) 8) Adhemax .RTM. Activator 30 0.5-4,
WB**) SF.sup.4) partially H/S*) 9) Rinsing 0.5 AI**) 10) Adhemax
.RTM. Accelerator 45-55 2-5 AI or US**) SF.sup.5) 11) Rinsing AI**)
12) Optional rinsing with 20-50 3 DI water**) US**) 13) Adhemax
.RTM. Ni 35 10 LFS.sup.6)***) 14) Rinsing 0.5 15) Optional rinsing
with 20-50 3 DI water**) US**) 16) Slight etching H.sub.2SO.sub.4
25 1 50 g/l 17) Adhemax .RTM. IC 30 1 or 2 Copper****) 18) Add
copper Cupracid .RTM. 25 20 5000****) 19) Flow rinsing twice 0.5
20) Slight etching 25 1 21) Rinsing 0.5 22) Bright nickel UniBrite
55 10 2002*****) 23) Rinsing 20 s 24) Chromium activation 25 1 25)
Bright chromium 40 2 Cr 843******) 26) Rinsing 0.5 27) Adhemax
.RTM. Neutralizer 45 1 Cr.sup.2) 28) Rinsing 0.5 29) Drying 10
.sup.1)Composition: 380 g/l chromic acid (CrO.sub.3), 380 g/l
H.sub.2SO.sub.4, 1 ml/l wetting agent, 12 mg/l Pd.sup.2+ (as
PdCl.sub.2); (in addition about 20 g/l Cr.sup.3+)
.sup.2)Composition: Hydroxylamine compound, alternatively also a
sulfide compound is possible, alternatively also in combination
with admixtures of mineral acid (hydrochloric acid or sulfuric
acid) .sup.3)Composition: 300 ml/l HCl (37% by weight):
.sup.4)Composition: Pd.sup.2+, Sn (Sn.sup.2+ + Sn.sup.4+), HCl (as
mentioned in the respective examples) .sup.5)Composition: 20-70
ml/l 96% by weight sulfuric acid, 40-100 g/l oxalic acid, nitrate
compounds .sup.6)Composition: contains Ni.sup.2+, reducing agent,
complexing agent, organic and inorganic stabilisers, ammonium
compounds .RTM. registered trademarks assigned to Atotech
Deutschland GmbH in various countries *)the parts to be treated
were lifted up and lowered a number of times in their position in
the bath in the processing tank in order to obtain an additional
mechanical movement in the operating process (improvement of the
rinsing effect through liquid flowing off many times) **)AI: air
injection; WB. movement of goods; FL: flooding; US: ultrasound; DI:
demineralised ***)electroless nickel bath, pH 9.1 ****)electrolytic
copper bath (bright copper, acid copper bath) *****)electrolytic
nickel bath (Watts nickel bath) ******)electrolytic chromium
bath
TABLE-US-00002 TABLE 2 Method Sequence for the Plastic
Metallisation Current Treatment Movement Temperature density period
of the Operation [.degree. C.] [A/dm.sup.2] [min] liquid
Etching.sup.1) 68 15 AI*) Adhemax .RTM. Neutralizer 45 2 AI*)
Pre-dipping solution.sup.2) 30 0.5 AI*) Adhemax .RTM. Activator 35
4 WB*) SF Rinsing 0.5 WB*) Treatment with 25, 45, 50 2-6 WB*)
ultrasound.sup.3) Adhemax .RTM. 45 5 AI*) Accelerator 1 Adhemax
.RTM. Ni LFS**) 40 8 FL*) Cuflex .RTM. 337***) RT*) 2.2 8 AI*)
Cupracid .RTM. 5000***) RT*) 3 25 WB/AI*) UniBrite 2002****) 55 4
15 WB/AI*) Cr 843*****) 40 10 .RTM. registered trademarks assigned
to Atotech Deutschland GmbH .sup.1)380 g/l CrO.sub.3, 380 g/l conc.
H.sub.2SO.sub.4, 2 ml/l fluorosurfactant, 12 mg/l Pd.sup.2+
.sup.2)300 ml/l HCl (37% by weight): .sup.3)DI water, treatment
with 40 kHz, 13 W/L *)AI: air injection; WB. movement of goods; RT:
room temperature; FL: flooding **)electroless nickel bath
***)electrolytic copper bath (bright copper, acid copper bath)
****)electrolytic nickel bath (Watts nickel bath)
*****)electrolytic chromium bath
TABLE-US-00003 TABLE 3 Method Conditions for Examples 7-18 Inv.
Inv. Inv. Inv. Inv. Inv. Example Example Example Example Example
Example Operation 7 8 9 10 11 12 Etching *) + + + + + + Adhemax
.RTM. Neutralizer + + + + + + Pre-dipping solution **) + + + + + +
Adhemax .RTM. Activator SF + .sup.1) + .sup.1) 2 .sup.3) .sup.1) +
.sup.1) + .sup.2) + .sup.2) Rinsing ./. ./. ./. + + + Treatment
with ultrasound in DI 2 .sup.3) .sup.4) 2 .sup.3) .sup.4) 2 .sup.3)
.sup.4) 2 .sup.3) .sup.5) 4 .sup.3) .sup.6) 4 .sup.3) .sup.6) water
Adhemax .RTM. Accelerator 1 + + + + + + Adhemax .RTM. Ni LFS ***) +
+ + + + + Cuflex .RTM. 337 ****) + + + + + + Cupracid .RTM. 5000
****) + + + UniBrite 2002 *****) + + Cr 843 ******) + + .RTM.
registered trademarks assigned to Atotech Deutschland GmbH *) 380
g/l CrO.sub.3, 380 g/l H.sub.2SO.sub.4, 2 ml/l fluorosurfactant, 12
mg/l Pd.sup.2+ **) 300 ml/l HCl (37% by weight): ***) electroless
nickel bath, pH 8.8-9.3 ****) electrolytic copper bath (bright
copper, acid copper bath) *****) electrolytic nickel bath (bright
nickel bath, Watts nickel bath) ******) electrolytic chromium bath
.sup.1) Composition: 41.3 mg/l Pd.sup.2+; 2.9 g/l Sn.sup.2+; 260
ml/l HCl (37% by weight) .sup.2) Composition: 30 mg/l Pd.sup.2+; 2
g/l Sn.sup.2+; 261 ml/l HCl (37% by weight) .sup.3) Treatment
period: 2 or 4 min .sup.4) .sup.5) .sup.6) Temperature for the
ultrasonic treatment: 4: 25.degree. C., 5: 45.degree. C., 6:
50.degree. C Inv. Inv. Inv. Inv. Inv. Inv. Example Example Example
Example Example Example Operation 13 14 15 16 17 18 Etching *) + +
+ + + + Adhemax .RTM. Neutralizer + + + + + + Pre-dipping solution
**) + + + + + + Adhemax .RTM. Activator SF 2 .sup.3) .sup.1) 2
.sup.3) .sup.1) + .sup.1) 2 .sup.3) .sup.1) 2 .sup.3) .sup.1) +
.sup.1) Rinsing + ./. / ./. + + Treatment with ultrasound in DI 4
.sup.3) .sup.6) ./. :/. ./. ./. ./. water Adhemax .RTM. Accelerator
1, + + .sup.6) + .sup.6) + .sup.6) + .sup.6) 6 .sup.3) .sup.6)
ultrasonic treatment Adhemax .RTM. Ni LFS ***) + + + + + + Cuflex
.RTM. 337 ****) + + + + + Cupracid .RTM. 5000 ****) ./. ./. ./. + +
UniBrite 2002 *****) ./. ./. ./. + + Cr 843 ******) ./. ./. ./. + +
.RTM. registered trademarks assigned to Atotech Deutschland GmbH *)
380 g/l CrO.sub.3, 380 g/l H.sub.2SO.sub.4, 2 ml/l
fluorosurfactant, 12 mg/l Pd.sup.2+ **) 300 ml/l HCl (37% by
weight): ***) electroless nickel bath: pH 9.1 ****) electrolytic
copper bath (bright copper, acid copper bath) *****) electrolytic
nickel bath (bright nickel bath, Watts nickel bath) ******)
electrolytic chromium bath .sup.1) Composition: 41.3 mg/l
Pd.sup.2+; 2.9 g/l Sn.sup.2+; 260 ml/l HCl (37% by weight) .sup.2)
Composition: 30 mg/l Pd.sup.2+; 2 g/l Sn.sup.2+; 261 ml/l HCl (37%
by weight) .sup.3) Treatment period: 2 or 4 min or 6 min .sup.4)
.sup.5) .sup.6) Temperature for the ultrasonic treatment: 4:
25.degree. C., 5: 45.degree. C., 8: 50.degree. C.
TABLE-US-00004 TABLE 4 Results of the Examples 7-18 of the
invention Invention Example Result 7 flawless metallisation, no
overgrowths 8 flawless metallisation, no overgrowths 9 flawless
metallisation, light overgrowths on the contact points on the edge
of the sleeve not to be metallised 10 flawless metallisation, light
overgrowths on the contact points on the edge of the sleeve not to
be metallised 11 flawless metallisation, no overgrowths 12 flawless
metallisation, no overgrowths 13 flawless metallisation, light
overgrowths on the contact points on the edge of the sleeve not to
be metallised 14 flawless metallisation, no overgrowths 15 flawless
metallisation, no overgrowths 16 flawless metallisation, no
overgrowths 17 flawless metallisation, no overgrowths 18 flawless
metallisation, no overgrowths
* * * * *