Note: Descriptions are shown in the official language in which they were submitted.
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"Method for applying decoration to a culinary utensil"
The present invention concerns a method of applying
a decoration based on fluorocarbon resin and a colored
pigment to part of one side of a metal culinary utensil.
Non-stick culinary utensils whose outside is also
covered with a non-stick coating usually have the outside
of the bottom dressed (i.e. the coating of fluorocarbon
resin such as PTFE is machined away).
The aluminum bottom therefore comprises a varying
depth spiral groove which is a problem because it rapidly
becomes soiled with use. Apart from being unattractive
in appearance, it is very difficult to clean and its
appearance deteriorates with further use.
A brushed finish can make the bottom easier to
clean, but is still unattractive, however.
Consideration has therefore been given to improving
the appearance of the bottom of the utensil by direct
application to the metal of the utensil of a decoration
based on fluorocarbon resin and pigment.
An object of the present invention is therefore the
direct application of a decoration which is strongly
adherent to one side, for example the bottom, of a metal
utensil, all of the side so decorated being resistant to
soiling and easy to clean.
In accordance with the invention, this method is
characterized by the following steps:
a) at least said one side of the utensil is
chemically attacked to form attachment microcavities
thereon;
b) a composition based on fluorocarbon resin and a
colored pigment is applied directly to predetermined
areas of said one side delimiting the decoration;
c) the fluorocarbon resin of said decoration is
cured by heating;
d) a pressing surface is applied to said one side,
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including said decoration, with sufficient pressure to
eliminate the microcavities outside the areas covered by
the decoration.
The effect of application of the pressing surface
to the side carrying the decoration is:
firstly to crush the fluorocarbon resin based
decoration, which strengthens its attachment in the
microcavities; and
secondly to crush the microcavities located outside
the decoration, the effect of which is to eliminate these
microcavities and to obtain a smooth, easy cleanable
surface with a metallic appearance.
In a preferred embodiment of the invention:
- an aluminum disk is etched with an acid to create
microcavities on both sides;
- a layer of fluorocarbon resin is applied to one
side of the disk;
- a decoration based on fluorocarbon res-in and
pigment is applied to the other side of the disk;
- the disk is heated to cure the fluorocarbon resin
present on both sides of the disk;
- a pressing surface is applied to the side
carrying the decoration to crush and so eliminate the
microcavities.
Other features and advantages of the invention will
emerge further in the following description.
In the appended drawings which are given by way of
non-limiting example:
- figure 1 is a part-sectional view of the bottom
of a culinary utensil having decoration applied by the
method of the invention;
- figure 2 is a view analogous to figure 1 showing
the condition of the surface after the pressing stage;
- figure 3 is a view analogous to figure 2 showing
an alternative embodiment of the 'invention in which a
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recess is formed during the pressing stage;
- figure 4 is a view analogous to figure 3 showing
a further embodiment in which a projection is formed
during the pressing stage;
- figure 5 is a plan view of the bottom of a frying
pan to which decoration has been applied in accordance
with the invention.
Referring to the appended drawing, the method of
forming on part of one side of a metal culinary utensil 1
a decoration 2 based on fluorocarbon resin and a colored
pigment comprises the following steps:
- a) at least said one side of the utensil is
chemically attacked to form attachment microcavities 3
thereon (figure l);
b) a composition based on fluorocarbon resin and a
colored pigment is applied directly to predetermined
areas of said one side delimiting the decoration 2;
c) the fluorocarbon resin of said decoration is
cured by heating;
d) a pressing surface 4 is applied to said one
side, including said decoration 2, with sufficient
pressure to eliminate the microcavities 3 outside the
areas covered by the decoration 2 (see figure 2).
The culinary utensil 1 is preferably pressed from a
sheet of aluminum or aluminum alloy.
The decoration 2 can be ap~lied to said side by
silkscreen printing by the method described in European
patent n 188 958 in the name of this ~pplicant.
In the figure 3 and 4 examples the pressing surface
4A, 4B has a raised pattern 7, 8 to produce in the area
of the side of the utensil outside the decoration 2 one
or more recesses or projections whose surface is also
made smooth by crushing the microcavities.
The decoration 2 could instead ~e applied from an
aqueous suspension by spraying PTFE~and pigment through a
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stencil, or by any other known method.
In practise, the procedure is as follows:
- - an aluminum disk 1 is etched with an acid to
create microcavities 3 on both sides;
- a layer of fluorocarbon resin is applied to one
side of the disk;
- a decoration 2 based on fluorocarbon resin and
pigment is applied to the other side of the disk;
- the disk is heated to a temperature between 400C
and 450C in an oven to cure the fluorocarbon resin
present on both sides of the disk;
- a pressing surface 4, 4A or 4B is applied to the
side carrying the decoration 2 to crush and so eliminate
the microcavities 3. The pressing must be carried out at
a pressure of not less than 600 kg/cm2.
Figure 5 shows a frying pan whose bottom has a
decorated area 5 and an external area 6 where the metal
is bare but has been made smooth by the method of the
invention.
The pressing operation not only attaches the
decoration 5 firmly to the microcavities but also makes
the area 6 smooth and easy to clean.
