U.S. patent application number 09/824239 was filed with the patent office on 2001-08-30 for noble metal preparation and its use to produce noble metal decorations by direct and indirect printing.
Invention is credited to Hackett, Stephen J., Keyn, Susanne, Schulz, Andreas, Zimmerbeutel, Elisabeth.
Application Number | 20010018483 09/824239 |
Document ID | / |
Family ID | 7873749 |
Filed Date | 2001-08-30 |
United States Patent
Application |
20010018483 |
Kind Code |
A1 |
Schulz, Andreas ; et
al. |
August 30, 2001 |
Noble metal preparation and its use to produce noble metal
decorations by direct and indirect printing
Abstract
The invention relates to a noble metal preparation for producing
noble metal decorations on decoratively fireable substrates by
direct printing and indirect printing (transfer technique). The
printing quality of the preparation containing noble metal
compounds and a binder system can be improved in that the binder
system comprises a resin mixture of a) 25 to 40 wt. % of polyamide
resins, b) 5 to 30 wt. % of sulfurized recent resins, c) 20 to 55
wt. % of rosin-modified resins, d) 0 to 30 wt. % of alkylphenol
resins and e) 0 to 30 wt. % of other resins compatible therewith or
of the reaction products, formed at 50 to 150.degree. C., of the
resin mixture mentioned and/or the reaction products, formed at 50
to 150.degree. C., of the resin mixture mentioned or the reaction
products of same containing the noble metal compounds in the
presence of a sulfur-containing gelling agent.
Inventors: |
Schulz, Andreas; (Offenbach,
DE) ; Zimmerbeutel, Elisabeth; (Rodenbach, DE)
; Keyn, Susanne; (Frankfurt, DE) ; Hackett,
Stephen J.; (Staffordshire, GB) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
7873749 |
Appl. No.: |
09/824239 |
Filed: |
April 3, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09824239 |
Apr 3, 2001 |
|
|
|
09350121 |
Jul 9, 1999 |
|
|
|
Current U.S.
Class: |
524/440 ;
524/275 |
Current CPC
Class: |
C03C 2217/251 20130101;
C03C 17/007 20130101; C03C 17/10 20130101; C03C 2217/445 20130101;
C03C 17/008 20130101; B44C 1/10 20130101; C03C 2217/72 20130101;
C03C 2217/479 20130101 |
Class at
Publication: |
524/440 ;
524/275 |
International
Class: |
C08K 003/08; C08J
003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 1998 |
DE |
198 31 141.9 |
Claims
1. A noble metal preparation for producing noble metal decorations
on decoratively fireable substrates, comprising: one or more noble
metal compounds, a medium, a binder system, and one or more fluxes,
wherein the binder system comprises a resin mixture of the
following resins or reaction products thereof: a) 25 to 40 wt. % of
one or more polyamide resins, b) 5 to 30 wt. % of one or more
sulfurised recent resins, c) 20 to 55 wt. % of one or more
rosin-modified resins, d) 0 to 30 wt. % of one or more alkylphenol
resins and e) 0 to 30 wt. % of other resins.
2. The noble metal preparation according to claim 1, wherein the
binder system contains at least two different rosin-modified resins
in a ratio by weight of from 10:1 to 1:10.
3. The noble metal preparation according to claim 1, wherein the
binder system contains at least one rosin-modified resin and an
alkylphenol resin in a ratio by weight of from 10:1 to 1:1.
4. The noble metal preparation according to claim 1, wherein the
binder system contains reaction products of two or more of the
resins, and wherein the reaction products are formed at 50 to
150.degree. C.
5. The noble metal preparation according to claim 1, wherein the
binder system contains reaction products or two or more of the
resins, and wherein the reaction products are formed at 50 to
150.degree. C. in the presence of the noble metal compounds and a
sulfur-containing gelling agent.
6. The noble metal preparation according to claim 1, wherein the
noble metal compounds and the resins or the reaction products
thereof are gelled by addition of 0.1 to 3 wt. %, with respect to
the preparation, of a sulfur-containing gelling agent.
7. The noble metal preparation according to claim 1, which contains
10 to 40 wt. % of solvent with a boiling point above 110.degree.
C.
8. The noble preparation according to claim 7, wherein the solvent
is at least one selected from the group consisting of aromatic and
cycloaliphatic hydrocarbons, terpenes, ketones, alcohols and
ethers.
9. The noble metal preparation according to claim 8, wherein the
solvent is an alkylated aromatic compound.
10. The noble metal preparation according to claim 1, which
contains 10 to 30 wt. % of waxes and less than 10 wt. % of organic
solvents.
11. The noble metal preparation according to claim 10, wherein the
waxes are selected from the group consisting of fatty alcohols,
fatty amides, polyolefin waxes and polyalkylene glycols.
12. The noble metal preparation according to claim 1, wherein the
sulfurised recent resin is a sulfurised dammar resin and the rosin
modified resin(s) is/are selected from the group consisting of
glycerol esters or rosin, pentaerythritol esters of rosin and
glycerol esters of maleic acid-modified rosin.
13. The noble metal preparation according to claim 1, wherein the
noble metal is selected from the group consisting of Au, Ag, Pd,
Pt, and mixtures thereof.
14. The noble metal preparation according to claim 1, wherein the
sulfurised recent resin is a sulfurised dammar resin.
15. The noble metal preparation according to claim 1, wherein the
binder system consists of 27 to 55 wt. % of one or more
rosin-modified resins, 7 to 20 wt. % of sulfurised dammar resin, 27
to 37 wt. % of polyamide resin and 0 to 30 wt. % of alkylphenol
resin.
16. The noble metal preparation according to claim 15, wherein the
binder system contains two rosin-modified resins present in a ratio
by weight of from 5:1 to 1:5 or a rosin-modified resin and an
alkylphenol resin present in a ratio by weight of from 4:1 to
1:1.
17. The noble metal preparation according to claim 1, wherein the
medium containing one or more soluble organic noble metal
compound(s) has been gelled at a temperature of 50 to 150.degree.
C. for 5 to 90 minutes, before or after addition of the flux(es),
in the presence of 0.1 to 3 wt. %, with respect to the preparation,
of one or more gelling agents selected from the group consisting of
sulfenamides, dithioamides or another organic compound with a di,
tri or tetrasulfide bridge.
18. The noble metal preparation according to claim 1, which
contains substantially soluble gold compounds selected from the
group consisting of resinates, sulforesinates, thiolates and
dithiolates as the noble metal compounds.
19. A process for preparing the noble metal preparation according
to claim 1, which comprises: mixing the noble metal compounds with
a solvent-containing or solvent-free medium and the binder system
at 50 to 150.degree. C. in the presence of a sulfur-containing
gelling agent before or after addition of the fluxes.
20. A transfer for producing a noble metal decoration on
decoratively fireable substrates, comprising: a support base, a
decorative layer and a film-forming covering layer, wherein the
decorative layer is produced using the noble metal preparation
according to claim 1.
21. A process for producing an article having a noble metal
decoration, which comprises: directly printing the noble metal
preparation according to claim 1 on the article, and firing the
article.
22. An article produced by the process according to claim 21.
23. A process for producing an article having a noble metal
decoration, which comprises: indirectly printing the noble metal
decoration on the article using the transfer according to claim 20,
and firing the article.
24. An article produced by the process according to claim 23.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to new noble metal preparations for
producing noble metal decorations on decoratively fireable
substrates such as glass, ceramic, bone china and porcelain, and a
process for their preparation. The preparations are suitable for
direct printing and indirect printing, which is why the invention
relates to both use of the noble metal preparation and to a
transfer containing such a noble metal preparation.
[0003] 2. Description of Related Art
[0004] Various noble metal preparations, in particular gold
preparations, which can be applied to decoratively fireable
substrates using direct or indirect printing, that is using a
transfer technique, are already known and lead to a bright or
burnishable noble metal decoration in the decoration firing
process. Preparations which lead to bright decorations are called
bright gold preparations. Bright gold preparations contain one or
more organic noble metal compounds which are substantially soluble
in an organic medium. Typical noble metal compounds for bright gold
preparations are so-called resinates, in particular however
sulforesinates, that is thiolates of terpenethiols, and synthetic
noble metal thiolates of various other organic mercapto compounds.
So-called burnished noble metal preparations, in particular
burnished gold preparations, contain the noble metal in the form of
compounds which are soluble and/or insoluble in the medium such as,
for example, gold sulfide and many elemental noble metals in powder
form. These preparations usually also contain one or more soluble
fluxes, in particular organic compounds, such as resinates,
carboxylates and alcoholates, in particular of elements from the
group comprising Rh, Bi, Cr, V, Ni, Co, Fe, Sn, Zr, Ta, Si, B and
Al, which have an effect on the structure of the noble metal film
and its adhesion to the substrate. A medium which is also suitable
for use in preparations for transfers substantially consists of one
or more binders which are mutually compatible and solvents for the
resins and noble metal compounds, or it may be largely solvent-free
and substantially consist of thermoplastic resins which are liquid
at the application temperature and optionally wax-like compounds.
Reference is made, by way of example, to U.S. Pat. Nos. 3,092,504
and 3,163,665, DE-AS 14 21 865 and EP-B 0 440 877.
[0005] In the case of transfers required for indirect printing, an
image layer consisting of the noble metal preparation or containing
this is applied directly to a support, in particular paper provided
with a water-soluble size layer or a wax layer or onto a base layer
and this layer is overfilmed directly or after applying an
intermediate layer containing a glass flux. Reference is made, by
way of example, to DE-AS 12 32 168, DE 36 16 547 C1 and DE 31 22
546 C2.
[0006] Although the binders contained in the medium in noble metal
preparations burn away during the firing process, they have a
considerable effect on the quality of the decoration. It has been
shown that dark decorations, decorations with streaks in the gloss
and/or insufficient burn-out and with inadequate adhesion may often
be produced, depending on the binder system used. Another reason
for defects in decorations may comprise soluble noble metal
compounds being dissolved out of the image layer during the
overfilming process, which leads to reduced brilliance, red fringes
and to the production of streaks and/or poorly defined decorations.
In the case of transfers, decoration defects result from tears.
[0007] To solve or reduce the problems mentioned above, various
processes have been suggested. According to DE-AS 12 32 168, an
impermeable protective layer for the covering layer, made of an
oxidisable or polymerisable, alkyd, phenol, urea or epoxy resin
material or a material containing dry oil, is placed between the
image layer and the covering layer. The additional layer reduces
fringes round the decoration but increases the cost.
[0008] The image layer in the transfer according to DE-PS 36 16 547
is based on a bright noble metal preparation which contains 8 to 30
wt. % of a thermoplastic resin. A resin from the group comprising
asphalt resin, polyamide resin, maleate resin, phenol resin, ketone
resin and epoxide resin is used as the thermoplastic resin. The use
of only one type of resin leads to qualitatively unsatisfactory
images in one way or another. Whereas, as has been demonstrated by
the inventor of the present application, although a thermoplastic
polyamide resin leads to satisfactory flexibility and extensibility
and thus to no tears in the transfer, sufficient compatibility with
the organic noble metal compounds and flux compounds is not
ensured, with the result that decoration defects, in particular
insufficient gloss, and/or problems during application, such as in
particular inadequate flow, occur. Although maleate resins often
lead to bright decorations, these are often also aesthetically too
dark; phenol resins often lead to insufficient burn-out and thus to
insufficient gloss and/or inadequate adhesion. The document
mentioned above does not disclose any binder mixtures for
overcoming the problems.
[0009] DE-AS 14 21 865 also discloses using media with more than
one binder, for example a mixture of a rosin and asphalt resin, in
noble metal preparations. A combination of this type, however,
leads to decoration defects with transfers, including tears.
[0010] A commercially available bright gold preparation for
indirect printing on glass and bone china is the product GGP 1230
from the Heraeus Co. Although this product enables the production
of tear-free and bright decorations, the dishwasher resistance,
that is the adhesion to glass, is regarded as unsatisfactory.
Visible damage to the decorations occurs after only 20 wash
processes in an automatic dishwasher for glassware. Smooth gold
films are not produced on bone china with GGP 1230. The adhesion of
decorations to various substrates depends both on the flux system
and on the binder system. The composition of the binder system in
this preparation cannot be determined in detail from chemical
analysis, but amide groups make the presence of a polyamide
probable. Another preparation, GGP 1215/Heraeus, contains amide
groups and structural elements of rosin; this resin is suitable for
porcelain and earthenware, but not for glass.
SUMMARY OF THE INVENTION
[0011] The object of this invention is to provide further noble
metal preparations, in particular bright gold preparations, which
are suitable for producing transfers and also lead to high-quality,
in particular pale, bright, tear-free and efficiently burn-outable
decorations on glass with improved dishwasher resistance.
[0012] A noble metal preparation which is directed at the
requirements of suitability for high-quality transfers has been
found, wherein the core factor is the binder system according to
the invention. Therefore, the invention provides a noble metal
preparation for producing noble metal decorations on decoratively
fireable substrates, containing one or more noble metal compounds
of Au, Ag, Pd or Pt, a medium, the binder system in which contains
a polyamide resin and a rosin resin, and one or more fluxes,
[0013] characterised by
[0014] a binder system consisting of a resin mixture of
[0015] a) 25 to 40 wt. % of one or more polyamide resins,
[0016] b) 5 to 30 wt. % of one or more sulfurised recent resins, in
particular sulfurised dammar resin,
[0017] c) 20 to 55 wt. % of one or more rosin-modified resins,
[0018] d) 0 to 30 wt. % of one or more alkylphenol resins and
[0019] e) 0 to 30 wt. % of other resins, apart from
non-plasticising resols,
[0020] or of the reaction products, formed at 50 to 150.degree. C.,
of the resin mixture mentioned and/or of the reaction products,
formed at 50 to 150.degree. C., of the resin mixture mentioned or
the reaction products of same containing the noble metal compounds
in the presence of a sulfur-containing gelling agent.
[0021] The sub-claims relate to preferred embodiments of the noble
metal preparation. According to one preferred embodiment, and this
is particularly expedient for preparing silver-containing gold
films, either at least two different rosin-modified resins in the
ratio by weight of 10 to 1 to 1 to 10 or at least one
rosin-modified resin and an alkylphenol resin in the ratio by
weight of 10 to 1 to 1 to 1, in addition to the sulfurised recent
resin and the polyamide resin, are used as binders.
[0022] According to another preferred embodiment, the binder system
consists of a resin mixture, 27 to 55 wt. % of one or more
rosin-modified resins, 7 to 20 wt. % of sulfurised dammar resin, 27
to 37 wt. % of polyamide resin and 0 to 30 wt. % of alkylphenol
resin, wherein in binder systems which contain two rosin-modified
resins these resins are present in a ratio by weight of 5 to 1 to 1
to 5 and in a binder system which contains a rosin-modified resin
and an alkylphenol resin these resins are present in the ratio by
weight of 4 to 1 to 1 to 1, and/or of reaction products of the
resin mixture mentioned formed in the presence or absence of a
sulfur-containing gelling agent.
[0023] The invention also provides a transfer, the
decoration-forming layer in which has been produced by using the
noble metal preparation according to the invention. The noble metal
preparation can be applied to a decoratively fireable substrate
such as glass, ceramic, porcelain, bone china and other siliceous
materials by a conventional direct printing process or by indirect
printing, that is using the transfer containing the preparation in
the image layer, and fired thereon under conventional conditions,
wherein high-quality decorations are obtained.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] The noble metal preparations according to the invention may
be bright noble metal or burnished noble metal preparations. Bright
preparations, in particular bright gold preparations which contain
compounds of silver and/or platinum or palladium to modify the
colour, in addition to one or more gold compounds, are preferred.
Bright gold metal preparations conventionally contain 6 to 15 wt. %
of noble metal in the form of organic, in particular
sulfur-containing, compounds which are soluble in the medium, such
as sulforesinates and other thiolates. Burnished gold preparations
contain, as an alternative to or in addition to soluble organic
gold compounds, insoluble inorganic noble metal compounds and/or
elemental noble metal; the gold content of this type of burnished
preparation is generally in the range 15 to 40 wt. %.
[0025] The medium for preparations according to the invention may
contain a solvent or be solvent-free. In the first case, the binder
is generally 15 to 25 wt. %, in the second case mostly 20 to 45 wt.
% of the mixture. The viscosity of the preparations can be
adjusted, apart from via the combination of resins, by the amount
and type of one or more solvents and/or by thermal treatment of the
binder combination and/or by gelling the medium containing the
noble metal compounds in the presence of a sulfur-containing
gelling agent at elevated temperature. To prepare screen-printing
pastes, the mixture of individual binders or a thermally
pre-treated mixture of the same is gelled in the presence of the
decoration-forming noble metal compounds and a sulfur-containing
gelling agent. Here, gelling is understood to mean a cross-linking
process, but one which still enables screen-printing.
[0026] The binder system according to the invention contains at
least three, but preferably four, resins from the classes mentioned
above in amounts in accordance with the claims. Only the
combination makes it possible to obtain a preparation with high
decorative quality which is suitable for transfers. The polyamide
resin(s) contribute substantially to the elasticity and flexibility
and thus to freedom from tears in the decorative layer in
transfers. The disadvantages of polyamide resins are alleviated by
the other resins. Here, the sulfurised natural resin has a
surprisingly large effect on the production of a bright finish.
Whereas a combination of one each of the resins (a), (b) and (c)
leads to acceptable decorative results with silver-free gold
decorations, there is a risk of dark and/or insufficiently
burnt-out decorations with silver-containing gold decorations.
Surprisingly, it is possible to overcome the problems mentioned by
using a combination of two different rosin resins (c) or one rosin
resin combined with an alkylphenol resin (d). The binder system
expediently contains the two resins in the ratios by weight
mentioned above.
[0027] Apart from the resin combination mentioned, the binder
system may also consist of the resins mentioned and in the amounts
mentioned in the form of reaction products produced during
production of the preparation at 50 to 150.degree. C., in
particular 80 to 140.degree. C. These types of reaction products
may be produced in particular when using reactive alkylphenol
resins.
[0028] In accordance with the alternative preferred for screen
printable noble metal preparations, the binder system consists of
reaction products such as the ones which may be formed from the
previously mentioned resin combination in the presence of a
sulfur-containing gelling agent and the noble metal compounds at 50
to 150.degree. C. The gelling agents may be agents which are known
from rubber vulcanisation. Examples are sulfur, polysulfides,
organic disulfides and oligosulfides, sulfenamides and
dithiocarbaminates, dithio-4,4'-dimorpholine being particularly
preferred. The amount of sulfurising agent used is generally in the
range 0.1 to 3 wt. %. During the gelling process, expediently
performed in the presence of a solvent, the viscosity of the
preparation increases. Sulfur bridges are probably formed between
constituents in the sulfur-containing binder system and/or with the
sulfur-containing noble metal compounds. The viscosity
characteristics required are produced by gelling; in addition the
storage stability of the preparation and the firing-on
characteristics are improved.
[0029] Alkylphenol resins are understood to be those
alkylphenol/formaldehyde resins in which the para-position,
optionally also the meta-position, in the phenol is/are
alkyl-substituted, in particular with a tert.-butyl, diisobutyl or
phenyl group, so that these resins do not cross-link, or cross-link
to only a small extent. The resins have a softening point in the
range of 40 to 120.degree. C. and are soluble in or can be diluted
with aliphatic hydrocarbons. Resins such as those described in
Kittel, "Lehrbuch der Lacke und Beschichtungen" (1961), vol. I.1,
pages 341-346 are suitable.
[0030] Suitable polyamide resins are those which are used as
lacquer resins and hot-melt adhesives. The softening point of the
polyamide resins is preferably in the range 50 to 150.degree. C.,
in particular in the range 80 to 120.degree. C. They are generally
aliphatic polyamides with structural elements from a dicarboxylic
acid and/or a diamine with more than 8 carbon atoms; the
dicarboxylic acid components in the polyamides are preferably
dimeric fatty acids.
[0031] Sulfurised recent resins are sulfurised resins from living
trees. Some of these natural resins have terpenoid structures.
Sulfurised resins based on sesquiterpenes, diterpenes and in
particular triterpenes are preferred. When sulfurising terpene
resins, quite considerable amounts of sulfur are taken up by these
in the form of thioether bridges, disulfide and oligosulfide bonds
and thiol groups. Sulfurised resins to be used according to the
invention preferably contain 5 to 20 wt. % of sulfur. Sulfurised
dammar resin with a sulfur content of 5 to 20 wt. %, preferably 8
to 12 wt. %, are particularly preferred.
[0032] Suitable rosin-modified resins are those which are used as
lacquer resins. These types of resins have a softening point in the
range 50 to 160.degree. C., in particular 80 to 140.degree. C. They
are, for example, glycerol esters of rosin or esters of primary
dihydric to hexahydric alcohols, such as pentaerythritol,
trimethylolpropene, trimethylolethane, dipentaerythritol and
neopentyl glycol with rosin, glycerol esters and pentaerythritol
esters of maleic acid-modified rosin and rosin-modified phenol
resins. Examples of these kinds of resins and their alcohol
components, acid values, colour and solubility can be obtained from
any current lacquer tables (for example, Karsten,
Lackrohstofftabellen (1987) 8th ed. Curt R. Vincentz Verlag,
Hannover).
[0033] When choosing the resin constituents in the context of this
invention, a person skilled in the art may ensure that the
components are compatible with each other and are soluble in the
chosen solvent system by means of orienting preliminary tests. This
test procedure is required in particular when additional different
resin(s) are also used in these preparations. Whereas in the case
of some optionally present other resins, for example asphalt
resins, the burn-out characteristics are not affected,
non-plasticising resols have proven to be unsuitable.
[0034] Solvent-containing preparations generally contain 10 to 40
wt. % of one or more solvents. Suitable solvents are aliphatic,
cycloaliphatic, aromatic hydrocarbons, in particular alkylated
aromatic compounds and terpenoid hydrocarbons, ketones, alcohols
and ethers. The boiling point of the solvent is expediently above
110.degree. C., in particular in the range from about 140 to
230.degree. C. The preparation preferably contains more than one
solvent, for instance a mixture of an alkyl aromatic compound, an
alkylcycloaliphatic compound, a carbocyclic ketone and an
alcohol.
[0035] Solvent-free or at least low-solvent (less than 10 wt. %)
preparations expediently contain wax-like compounds to adjust to
optimum printing properties, for example as a solution promoter,
adjusting the softening point and viscosity/temperature behaviour.
Suitable substances are polyolefin waxes, fatty alcohols, fatty
amides and polyalkylene glycols. Preparations according to the
invention may also contain conventional plasticisers such as
dibutyl phthalate.
[0036] Preparing the preparations comprises mixing and homogenising
the binder. The individual resins are expediently placed in contact
with each other in sequence at 50 to 150.degree. C., with stirring,
wherein in the case of a solvent-containing system solvents may be
present. According to a preferred embodiment, a sulfurised recent
resin, for example sulfurised dammar resin, and one or more
rosin-modified resins are stirred in an alkylaromatic solvent at 80
to 140.degree. C. until the mixture is homogeneous, then, if
present, the alkyl phenol resin is added and the mixture is again
homogenised and lastly the polyamide resin is introduced and
homogenised at the temperature mentioned above. The noble metal
compounds are introduced into the binder system. If desired, and
this corresponds to a particularly preferred embodiment for screen
printable pastes, the mixture is gelled at 50 to 150.degree. C.,
preferably 80 to 140.degree. C., with 0.1 to 3 wt. %, in particular
0.5 to 2 wt. %, of a sulfur-containing gelling agent. The amount of
sulfurising agent used is governed by the processing viscosity
required. More sulfurising agent is likely to be required for
preparations with a low binder content. During this gelling stage,
sulfurisable constituents of the binder and/or the noble metal
thiolates are cross-linked via sulfide, disulfide or oligosulfide
bridges. Sulfurisable binders are those which are unsaturated
and/or are already partly sulfurised. The flux may be added before
or after thermal treatment with a sulfurising agent. Preparations
according to the invention generally contain a conventional amount
of one or more fluxes known to a person skilled in the art. Organic
compounds of Rh, Cr and Bi are conventionally present as fluxes,
but often also other compounds such as Si, Al, Co, Ni, Sn, Ta or Ti
compounds.
[0037] Preparations according to the invention may be used to
produce transfers. These types of transfers comprise a support base
with a conventional water-soluble or thermally softening separating
layer, a decorative image layer consisting of the noble metal
preparation according to the invention and a film-forming covering
layer consisting of a conventional film-former, for example a
methacrylate resin.
[0038] The transfer may also have a base layer located between the
separating layer and the image layer and/or a top layer located
between the image layer and the covering layer. The base layer may
be a layer containing an oxide and/or a glass frit, which improves
the adhesion and/or means that matt decorations can be produced
(see e.g. DE-PS 31 22 546). The top layer is, for example, a layer
containing a glass frit, which means that abrasion-resistant
decorations can be produced (see e.g. DE-PS 36 16 547). The image
layer is applied in a conventional way, preferably using screen
printing.
[0039] Both the noble metal preparation according to the invention
and also the transfer containing this type of preparation can be
used in a known way to produce noble metal decorations on
decoratively fireable substrates. Conventional printing processes
may be used for direct printing, such as screen printing and pad
printing. Obviously, application of the preparation with brushes or
using a banding machine is also possible. Substrates for direct and
indirect printing are, for example, glass, ceramic, bone china and
porcelain. The decoration applied to the support is fired in a
known way under firing conditions appropriate to the substrate.
[0040] Use of the preparation according to the invention using a
direct printing or indirect printing process leads to high-quality
decorations. Bright preparations lead to pale, bright and tear-free
decorations. The following examples explain the invention.
EXAMPLES
[0041] Preparing the preparations (general method)
[0042] A 50 wt. % strength solution of sulfurised dammar resin in a
mixture of pine oil and toluene with a sulfur concentration in the
solution of 9.1% (=gD) and the rosin resin(s) from the group
comprising glycerol esters of rosin (=K.sub.1; softening point
90.degree. C.), pentaerythritol esters of rosin (= K.sub.2;
softening range 113 to 123.degree. C.) and glycerol esters of
maleic acid-modified rosin (=K.sub.3; softening point 142.degree.
C.) were homogenised at 125.degree. C. in the presence of an
alkylaromatic solvent. Then, if present, an alkylphenol resin with
a melting range of 50 to 60.degree. C. (=APH) and in examples 12
and 15 a non-plasticising resol with a melting range of 45 to
55.degree. C. (=PH) were added and homogenised at 125.degree. C.
Finally, a polyamide resin based on a fatty acid dimer with a
softening point of about 100.degree. C. (=PA) was incorporated into
the system at the same temperature. Reactive groups in the resins
could react with each other at the chosen temperature. The noble
metal compounds and flux and, if required, more solvent were added
to she binder system.
[0043] Since preparation of the preparations in the examples given
in the table included a gelling stage, this was performed before
adding the flux by adding the gelling agent di-4,4'-morpholino
disulfide to the binder systems containing the decoration-forming
noble metal compounds, prepared as described above, and performing
gelling at 110 to 120.degree. C. over the course of 5 to 90
minutes. In examples 1 to 15, 1.07 g, in example 16 1.00 g, in
example 17 0.79 g and in examples 18 to 21 1.04 g of
di-4,4'-morpholino disulfide were used.
[0044] In the examples, the flux combinations A, B or C given in
the table were used, these containing the following metals in the
form of resinates (wt. %)
1 A: 0.03 Rh; 0.08 Bi; 0.03 Zr; 0.01 B; 0.008 Cr; 0.04 Co; 0.04 V;
0.02 Ta. B: 0.03 Rh; 0.05 Si; 0.04 Cu; 0.02 B; 0.04 Bi; 0.03 Zr;
0.10 S; 0.06 V. C: 0.06 Rh; 0.03 Si; 0.06 Ni.
[0045] Solvent-containing preparations also contained alkylaromatic
compounds, cyclohexanone, benzyl alcohol and methyl cyclohexanol in
the ratio of about 3:3:2:1, in addition to the pine oil in the
sulfurised dammar. The printing viscosity of the pastes was in the
range 2000 to 10,000 mPa.s. The solvent content of the
thermoplastic preparation (=example 20) was less then 10%; but the
preparation contained C.sub.16-C.sub.18 fatty alcohols in order to
adjust the printing viscosity.
[0046] Examples 1-17, according to the invention or not according
to the invention, were performed using a gold sulforesinate (50%
Au); the gold content of the preparations was 9.8 wt. % each time.
The preparations in examples 1 to 16 also contained 5 wt. % of a
silver mercaptide (20% Ag). Examples 17 to 19 contained only the
gold sulforesinate as a decoration-forming noble metal compound (Au
consent 98%). The burnished gold preparation contained the
sulforesinate in conventional amounts (=9.8 % Au) and also
elemental Au powder; total Au content 26%. Examples 1 to 15 also
contained 3.3 wt. % of dibutyl phthalate, examples 1 to 11 also
contained 3.3 wt. % of camphor.
[0047] For indirect printing, transfers were prepared and these
applied in a conventional way. The printing paste was applied to
metapaper using screen printing, dried and then overfilmed with a
commercially available film solution (80450 from Cerdec AG). Direct
printing (examples 10i and 11i and 20) was performed by screen
printing. Direct printing of the thermoplastic preparation in
example 20 was performed using a heated screen.
[0048] Firing conditions on glass: heating to 600.degree. C. over 1
hour, 15 min waiting time, cooling to 25.degree. C. over 1
hour.
[0049] Firing conditions on bone china (BC) (examples 17 to 19):
250.degree. C./min, rate of heating to 780.degree. C., 45 min
waiting time, cooled. On porcelain (example 17): 400.degree. C./h
rate of heating, 10 min waiting time at 820.degree. C.
[0050] Firing conditions for the burnished gold preparation
(example 21), which contained a glass frit and a rhodium-containing
high-temperature rapid firing flux: rate of heating 2400.degree.
C./h, waiting time 1 min.
[0051] Details relating to the binder systems, decoration-forming
noble metals in the preparations and firing results during indirect
printing and sometimes direct printing on glass, bone china and
porcelain are given in the table. Unless stated otherwise, indirect
printing was used.
2 Decora- Binder Noble tion No. gD APH PA K.sub.1 K.sub.2 K.sub.3
metal Flux Substrate quality Comments 1/E 3 5 10 Au/Ag A Glass 0
bright, but slightly dark 2/E 3 2.5 5 7.5 Au/Ag A Glass + bright,
paler than 1/B 3/E 3 5 5 5 Au/Ag A Glass ++ bright, paler than 2/E
4/CE 3 7.5 5 2.5 Au/Ag A Glass - moderately bright 5/CE 3 10 5 0
Au/Ag A Glass -- slightly bright 6/CE 3 10 7.5 Au/Ag A Glass -
pale, but distinct smears 7/E 3 2 7.5 8 Au/Ag A Glass ++ pale and
bright 8/E 3 4 7.5 6 Au/Ag A Glass ++ pale and bright 9/E 3 6 7.5 4
Au/Ag A Glass 0 pale, slight smears 10/E 3 6.25 2 8 Au/Ag A Glass
(i)++ bright and pale with (ii)++ direct (i) and indirect (ii)
printing 11/E 3 6.25 2 8 Au/Ag A Glass (i)++ bright and pale with
(ii)++ direct and indirect printing 12/CE 3 2 PH 6.25 8 Au/Ag A
Glass -- incomplete burn-out 0 APH 13/E 3 2 6.25 8 Au/Ag A Glass ++
bright 14/E 3 2 6.25 8 Au/Ag A Glass ++ bright 15/CE 3 8 PH 6.25
Au/Ag A Glass -- incomplete burn-out 2 APH 16/E 5 2 6.25 6.5 Au/Ag
B Glass ++ bright 17/E 5 2 5 6.5 Au C BC ++ bright Porc. ++ bright
18/E 3.5 5 10 Au C BC + bright 19/CE 6 14 Au C BC -- could not be
printed 20/E 5 2 6 5 Au/Ag B Glass ++ bright; direct printing 21/E
3.4 0.9 4.3 6 Au HTS Porc. ++ silky bright after burnishing
[0052] Decoration quality: ++ very good
[0053] + good
[0054] 0 acceptable
[0055] - mediocre
[0056] -- poor
[0057] BC: bone china
[0058] Porc. porcelain
[0059] E: according to the invention
[0060] CE: not according to the invention
[0061] The test results show that preparations which contain binder
systems in accordance with the claims enable the production of
high-quality decorations.
* * * * *