Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to a method for producing a
laminate combination of paper and at least one lacquer layer and
one metal layer.
In the prior art, two methods are known to provide
papers with metallic surfaces. According to the one method,
aluminum is laminated to paper by means of a dry or wet
laminating process. If required, a wax laminating process may
also be employed. This process is expensive and does not produce
a highly glossy mirror effect. The material produced in this way
is very stiff which is a great impediment for further processing.
Further difficulties arise in the use of labels made of such a
laminate combination. They can be removed from the labelled
objects only by means of very strong leaching solutions so that,
for example, strong leaching solutions must be used to further
process reusable bottles.
In the other process, papers are often used on which a
prepared lacquer layer is metallized. The metallization is
effected in a vacuum of at least 5 to 10 4 of. In order to
produce such a vaccum, thick cardboards and papers must be dried
to a moisture content of, for example, about 3%. This requires a
considerable amount of energy. Moreover, such laminates become
expensive because the lacquer layer to be applied to the dried
carrier penetrates heavily into the pores of the carrier to that
the lacquer of a layer which fills the pores must be applied to
the carrier very thickly.
It is thereEore the object of the present invention to
improve the production of a multilayer combination so that a
reflecting surface is obtained with the use of the most
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inexpensive papers.
This object is accomplished according to the invention
by transferring the lacquer layer and the metal layer as a whole
onto the paper in a transfer process.
The mirror effect of the metal layer in this laminate
combination is independent of the consistency of the paper
surface. The entire laminate combination is first built up on a
carrier foil and is transferred as a unit to the paper. This
method has the additional advantage that the paper need not be
predried before application of the metallization. This saves
considerable costs in energy, investment and time.
According to an embodiment of the invention, the present
invention provides a method of making a laminate combination
comprising the following steps: (a) applying a continuous
peelable first lacquer layer to one face of a carrier foil of
indeterminate length; (b) applying a continuous metal layer to
that face of said lacquer layer which is oriented away from said
carrier foil; (c) applying a continuous very thin second lacquer
layer to said metal layer; (d) continuously advancing a composite
web formed of the carrier foil of indeterminate length, the first
and second lacquer layers and the metal layer carried on said
carrier foil; (e) continuously advancing a paper web of
indeterminate length; (f) bonding the advancing composite web, by
means of an adhesive layer, to the entire surface of one face of
the advancing paper web; and (g) removing said carrier foil from
said first lacquer layer.
Further details of the invention become evident from the
following detailed description and the enclosed drawings in which
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a preferred embodiment of the invention is illustrated as an
example.
In the drawings:
Figure 1 is a cross-sectional view of a laminate before
separation of the carrier foil;
Figure 2 is a schematic sketch of a system for glueing
the carrier foil to the paper and subsequently separating the
carrier foil; and
Figure 3 is a Vi2W of the system according to Figure 2
in which the laminate is enlarged from beginning of pressing on
the paper to separating the carrier foil from the coated paper.
The laminate provided for the transfer of the laminate
combination essentially includes a carrier foil, preferably a
polyester foil 1, a separating layer 2, which may be omitted
under certain circumstances if a basic lacquer 3 is used which
does not have much affinity to the carrier foil, a
vacuum-deposited metal layer 4, a laminate adhesive 5, as well as
a paper layer 6. The starting point of a method for producing
the laminate combination is a transfer foil. This transfer foil
comprises the carrier foil 1 having as glossy and reflective a
surface as possible. On this carrier foil there is provided the
separating layer 2 onto which in a proparatory process step the
lacquer layer 3 is applied thinly. The desired metal layer 4 is
then vapor-deposited thereonto in a vaccum. A second, very thin
lacquer layer 4a is then applied to the metal layer 4. The
second lacquer layer 4a is gas impervious and heat insulating.
The thus prepared transfer foil combination 7 is coated
by means of a lacquering mechanism 8 with an adhesive 9.
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The transfer foil 7a prepared in this manner may be
dried in a drier 10 if the adhesive 9 is a dry laminate adhesive.
When a wet adhesive is employed, the drier 10 can be eliminated.
After leaving the drier 10, the transfer foil 7a is
brought to a calender 11. Between the two rolls of the calender
11 the adhesive layer 9 of the transfer foil 7a is pressed
together with the paper 6 so that it is tightly glued to the
transfer foil combination 7 and forms a unit with it. This unit
is cooled on the surface, if required, with a cooling roll 13.
After leaving the cooling roll 13, the carrier foil 1 may be
separated from the lacquer 3. For further use it is wound on a
reel 14. The laminate combination formed by the paper 6, the
metal layer 4 and the basic lacquer 3 is wound onto another reel
15.
The separating layer 2 enhances the removal of the
lacquer layer 3 from the carrier foil 1. If the lacquer layer 3
does not have a strong affinity to the carrier foil 1, this
separating layer 2 need not be used.
When selecting the carrier foil 1, particular care must
be taken that it has as smooth, highly glossy and reflective a
surface as possible. The quality of the metal layer depends upon
the quality of the surface of this foil 1. It is also possible
to transfer matte effects or brush effects of the carrier foil 1
by means of the basic lacquer 3.
Dispersion adhesives and solvent adhesives can be used
as adhesive 5 in the form of dry or wet adhesives; wax containing
adhesives can also be used for attaching the paper layer 6.
In the selection of the basic lacquer 3 various fields
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of application can be considered. In particular, the use of a
saponifiable adhesive should be considered which can be removed
during conventional cleaning processes. When the laminate is
used for the production of labels, such feature may be of
advantage if the labels are to be used, for example, on bottles
which are suitable for reuse after cleaning. For the same reason
it is of advantage to also make the lacquer layer 3 saponifiable.
Since the individual layers of the laminate produced
according to the invention are very thin, the laminate is very
flexible and thus easy to work with. It can be produced at
relatively low material costs and is thus inexpensive.
Intermediate drying and subsequent rewetting of the carrier are
not necessary.
It is also possible to use a polycarbonate foil instead
of the polyester foil. The former also has a highly glossy
surface and is therefore suitable for application of the lacquer
and metal layers 3,4. Moreover, it is conceivable to apply the
adhesive 5, as a departure from the showing in Figure 2, not to
the metal layer 4 but to the paper 6. In this case, the
lacquering mechanism 8 and possibly the drier 10 must be disposed
in the path of the paper web 6.
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