Note: Descriptions are shown in the official language in which they were submitted.
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Method for producing a security element and a security element obtainable by
method
[00011 This invention relates to a security element which has a substrate with
at
least one opening, whereby the opening is closed on one side with an at least
partly
translucent or transparent foil, and a coating is located on the side of the
substrate
opposing the foil, in the region of the opening and substantially in the
region of the foil
area, and whereby the coating is not present, or substantially not present,
within the
opening. The invention relates furthermore to methods for producing such a
security
element. The security element of the invention is applied to a value document
or is part
of a value document. When the security element is part of a value document,
the
opening is formed in the substrate of the value document.
[00021 A value document for the purposes of this invention is in particular a
bank
note, a paper of value, a credit card or identification card, a passport, a
deed or the like,
a label, a package or another element for product authentication.
[00031 From WO 2005/116335 Al there is known a method for producing security
paper with at least one transparent region for value documents. The security
paper
consists here of at least one ply of substantially non-transparent material
which has an
opening or a window. The opening is first closed on one side by a transparent
cover
ply, in particular a foil or lacquer layer, and subsequently filled with a
transparent
filling by extrusion coating.
[0004] The invention is based on the object of developing a generic security
element so as to further increase the protection from forgeries.
[00051 This object is achieved by the features of the independent claims.
Developments of the invention are the subject matter of the dependent claims.
[00061 A first aspect of the invention relates to a method for producing a
security
element which has a substrate with at least one opening, whereby the opening
is closed
on one side with an at least partly translucent or transparent foil,
comprising an
application of a coating to one side of the substrate, a producing of a
through opening
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in the substrate and the coating applied to the substrate, and an application
of an at
least partly translucent or transparent foil to the side of the substrate
opposing the
coating, so that the opening is closed on one side with the at least partly
translucent or
transparent foil and the coating is arranged on the substrate substantially in
the region
of the foil area.
[0007] A second aspect of the invention relates to a method for producing a
security element which has a substrate with at least one opening, whereby the
opening
is closed on one side with an at least partly translucent or transparent foil,
comprising
an application of a coating to a substrate provided with a through opening, in
the
region of the opening, so that the coating is not present, or substantially
not present,
within the opening, and an application of an at least partly translucent or
transparent
foil to the side of the substrate opposing the coating, so that the opening is
closed on
one side with the at least partly translucent or transparent foil and the
coating is
arranged on the substrate substantially in the region of the foil area.
[0008] A third aspect of the invention relates to a method for producing a
security
element which has a substrate with at least one opening, whereby the opening
is closed
on one side with an at least partly translucent or transparent foil,
comprising an
application of an at least partly translucent or transparent foil to a
substrate provided
with a through opening, in the region of the opening, and an application of a
coating to
the side of the substrate opposing the foil, so that the coating is not
present, or
substantially not present, within the opening, the opening is closed on one
side with
the at least partly translucent or transparent foil and the coating is
arranged on the
substrate substantially in the region of the foil area.
[0009] A fourth aspect of the invention relates to a security element which
has a
substrate with at least one opening, whereby the opening is closed on one side
with an
at least partly translucent or transparent foil, and a coating is located on
the side of the
substrate opposing the foil, in the region of the opening and substantially in
the region
of the foil area, and whereby the coating is not present, or substantially not
present,
within the opening.
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[00101 The security element according to the fourth aspect of the invention is
obtainable by the method according to the first aspect of the invention or
alternatively
by the method according to the second or third aspect of the invention.
[00111 In general, the physical properties, in particular the flatness, of a
substrate
having an opening are substantially influenced by a one-sided application of a
foil. The
expansibility of the substrate which consists of paper and/or a plastic foil
is dependent
on the parameters of temperature, moisture and orientation of the fiber
strands or
polymer strands of the paper or foil. If a substrate provided with a through
opening is
closed on one side with a foil whose expansibility differs strongly from that
of the
substrate, changes in moisture and/or temperature can strongly impair the
flatness of
the substrate.
[00121 According to the invention, bulges of the substrate as a result of
moisture
and temperature influences can be avoided by closing the substrate provided
with an
opening with an at least partly translucent or transparent foil on one side
and applying
a coating to the side of the substrate opposing the foil, in the region of the
opening and
substantially in the region of the foil area, i.e. the area of the foil. The
coating is so
applied here that no, or substantially no, coating material is present within
the opening,
i.e. the coating material does not "flow into" the opening. The coating causes
an
opposing force, as it were, to be built up to the at least partly translucent
or transparent
foil. The security element of the invention proves to be advantageous in
particular
upon the stacking of value documents which include the security element, or
upon a
further processing, e.g. printing or embossing, because a flat surface is
necessary here.
Special advantages of the security element of the invention are that the at
least partly
translucent or transparent foil applied over the through opening creates an
unlimited
overprintability of the region of the opening and ensures, in connection with
the
coating applied to the side of the substrate opposing the foil, an elevated
stability upon
creasing or bending through load and stress compensation.
[00131 Hereinafter the invention will be described in detail with reference to
preferred embodiments, to which the invention is in no way to be limited,
however.
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The described single features and embodiments hereinafter described are
inventive
taken alone, but are also inventive in combination.
[00141 According to a first preferred embodiment, a security element which has
a
substrate with at least one opening, whereby the opening is closed on one side
with an
at least partly translucent or transparent foil, is produced by applying a
coating to one
side of the substrate, thereafter producing a through opening in the substrate
and the
coating applied to the substrate, and subsequently applying an at least partly
translucent or transparent foil to the side of the substrate opposing the
coating, so that
the opening is closed on one side with the at least partly translucent or
transparent foil
and the coating is arranged on the substrate substantially in the region of
the foil area.
[00151 The substrate can be of single- or multi-ply configuration and consist
of
paper and/or a plastic foil. As paper there can be used any type of paper, in
particular
cotton paper. It is of course also possible to use paper that contains a
content x of
polymeric material in the range of 0 < x < 100. As a plastic foil there can be
used e.g. a
polyester foil. The foil can further be stretched uniaxially or biaxially. The
stretch of
the foil has the consequence, inter alia, that it acquires polarizing
properties which can
be utilized as a further security feature. It can also be expedient when the
substrate
material is a multilayer composite which has at least one layer of paper or a
paper-like
material. Such a composite is characterized by an exceptionally great
stability, which
is of great advantage for the durability of the paper. It is also conceivable
to use as a
substrate material a multilayer, paper-free composite material. Said composite
material
can be used advantageously in certain climatic regions of the earth. All
materials used
as the substrate material can have additives which serve as authentication
features. In
this connection one will primarily consider luminescent substances which are
preferably transparent in the visible wavelength range and can be excited in
the
invisible wavelength range by a suitable aid, e.g. a radiation source emitting
UV or IR
radiation, in order to produce a luminescence that is visible or at least
detectable with
aids.
[00161 The coating which is applied to the one side of the substrate can be a
self-
supporting layer, such as a foil. Suitable foils are e.g. polyolefin foils
(e.g. of PE
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(polyethylene), PP (polypropylene) or cyclo-olefinic copolymers), foils of
polyolefin
derivatives or of polycarbonate, PMMA, in particular PET (polyethylene
terephthalate), PP, PA (polyamide). The foil can be applied to the substrate
for example
by means of an adhesive or a lacquer. As adhesives there can be employed for
example
hot-melt adhesives or reaction lacquers. Suitable adhesives for applying the
foil are
e.g. polyvinyl acetates, polyvinyl chloride derivatives, acrylates,
polyurethanes,
polyesters, copolymers of these groups as well as UV adhesives.
[0017] The coating which is applied to the one side of the substrate can also
be a
non-self-supporting layer, i.e. a layer that is not processable as a separate
layer but
only together with a thicker carrier layer which is optionally laminated with
further
layers to form a multilayer carrier.
[0018] For forming the coating which is applied to the one side of the
substrate and
which is a non-self-supporting layer, lacquers can be used. Suitable lacquers
are
solvent-containing two-component lacquers, aqueous dispersions and UV
lacquers,
preferably UV lacquers with a high solids content. As a lacquer there can be
employed
a transparent lacquer or a colored lacquer.
[0019] The coating applied to the one side of the substrate and being a non-
self-
supporting layer preferably has cross-linked gum arabic. Further preferably,
the
coating consists substantially of cross-linked gum arabic. Gum arabic is a
branched
polysaccharide which has weakly acidic properties and occurs in natural form
as
neutral or weakly acidic potassium salt, calcium salt or magnesium salt. For
forming
the coating there can be used an aqueous mixture which contains gum arabic
(e.g.
"Quickgum Type 8074" from the company Norevo GmbH) converted to the H+ form
by means of an ion exchange resin (e.g. "Levatit Monoplus SP 112 H" from the
company Lanxess), and a cross-linking agent. As a cross-linking agent there
can
advantageously be employed a polyfunctional aziridine cross-linker (e.g.
"Crosslinker
CX-100" from the company DSM-Neoresins). The aqueous mixture can be applied to
the substrate e.g. by printing, preferably by screen printing, and thereafter
dried at
ambient temperature or at elevated temperature and thereby cross-linked. The
gum
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arabic treated by means of ion exchange resin and converted to the H+ form has
a very
advantageous waterproofness after cross-linking.
[00201 As an alternative to the hereinabove mentioned use of cross-linked gum
arabic, the coating applied to the one side of the substrate and being a non-
self-
supporting layer can have starch (amylose) cross-linked by means of a cross-
linking
agent. In this case it is preferred that the coating consists substantially of
starch
(amylose) cross-linked by means of a cross-linking agent. For forming the
coating
there can be used an aqueous mixture which contains soluble starch, i.e.
amylose, and
a cross-linking agent. As a cross-linking agent there can advantageously be
employed
a di- or higher-functionalized isocyanate cross-linker. The cross-linking
agent should
preferably be emulsifiable or dispersible in water. The aqueous mixture can be
applied
to the substrate e.g. by printing, preferably by screen printing, and
thereafter dried at
ambient temperature or at elevated temperature and thereby cross-linked.
[00211 Preferably, the coating which is applied to the one side of the
substrate is
extruded or laminated. In the case of an extrusion coating, a melt is for
example
pressed by means of a screw through a nozzle. If it is a slot nozzle, a film
corresponding to a foil can be placed over the substrate and connected
thereto. In the
case of coating by lamination, solvent-containing or solvent-free one-
component and
two-component systems can be used as laminating adhesives.
[00221 Likewise, the coating can be applied to the substrate by printing, in
particular by a gravure, flexographic, screen, offset or transfer printing
method.
100231 The term "through opening" refers to a through hole, i.e. an opening
that
breaks in a straight line through both the substrate and the coating
optionally applied to
the substrate.
[00241 The through opening which is produced in the substrate and the coating
applied to the substrate can be produced by punching or cutting, in particular
by laser
cutting.
[00251 The through opening can have arbitrary outline contours and be for
example
of circular, oval, rectangular, trapezoidal, star-shaped or also strip-shaped
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=
configuration. The through opening can be composed of several partial through
openings which are separated by bars of the substrate and the coating applied
to the
substrate. The partial through openings can have arbitrary outline contours
and are
preferably used as an additional design element. For producing the respective
partial
openings, all the above-mentioned methods for producing the opening of the
invention
can be employed analogously.
[0026] The at least partly translucent or transparent foil which is applied to
the side
of the substrate opposing the coating, so that the opening is closed on one
side with the
at least partly translucent or transparent foil, is preferably of transparent
configuration.
Transparent is to be understood in this connection to mean a light
transmission of at
least 90% of the impinging light, while translucent means a light transmission
of less
than 90%, preferably between 80% and 20%. Preferably, the at least partly
translucent
or transparent foil for closing the opening has at least one translucent
region in the
region of the opening. In particular, it is preferred that the at least partly
translucent
foil for closing the opening has at least one transparent region in the region
of the
opening. As materials for the at least partly translucent or transparent foil
there can be
used for example the plastics PET (polyethylene terephthalate), PBT
(polybutylene
terephthalate), PP (polypropylene), PA (polyamide) and PE (polyethylene). The
foil
can further be stretched uniaxially or biaxially.
[0027] The at least partly translucent or transparent foil for closing the
opening can
be applied, in particular laminated, to the substrate as a strip, patch, label
or embossing
foil element. Preferably, the application is effected by means of an adhesive
layer or
lacquer layer. As an adhesive there can be employed the hereinabove mentioned
adhesives. A patch in this connection is a label-shaped single element. A
strip has a
width that is substantially smaller than its length, whereby the strip
preferably reaches
from one edge of the substrate to an opposing edge thereof.
[0028] The hereinabove mentioned coating which is applied to the one side of
the
substrate, and/or the hereinabove mentioned at least partly translucent or
transparent
foil can expediently have at least one security feature. The security feature
is in
particular a diffractive structure, such as a (volume) hologram, or a hologram-
like
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diffractive structure, a matt structure, a metallization, whereby several
different-
colored metals can also be employed, a perforation, a lens structure or micro-
mirror
structure, a micro-optic system, in particular a micro-optic moire
magnification
arrangement, a thin-film element, a polarization filter or a print which has
at least one
substance with optically variable, luminescent, electrically conductive or
magnetic
properties. Suitable substances with optically variable properties are e.g.
effect
pigments, in particular pigments produced on the basis of liquid-crystal
polymers, or
so-called pearl luster pigments, such as the silver white, gold luster or
metal luster
pigments sold under the name Iriodin or Colorcrypt by the company Merck KGaA.
Both pigments based on liquid-crystal material and pearl luster pigments are
translucent in themselves. Suitable substances with optically variable
properties are
further interference-layer pigments. Interference-layer pigments typically
have a thin-
film structure which expediently contains at least a reflective layer, an
absorber layer
and a dielectric spacer layer arranged between the reflective layer and the
absorber
layer. Interference-layer pigments can be translucent in themselves, although
opaque
interference-layer pigments are also known.
[00291 The at least partly translucent or transparent foil can have a security
feature
in particular in the region of the opening of the security element of the
invention.
[00301 The coating applied to the substrate can be substantially transparent.
Alternatively, the coating applied to the substrate can have a color
perceptible to the
viewer.
[00311 The step of applying the coating to the substrate can be part of a
printing
method intended for a bank note, in particular gravure printing, flexographic
printing,
screen printing, offset printing or transfer printing.
[00321 The coating applied to the substrate can be of single- or multi-ply
configuration and consist of one, two, three, four or more plies. In
particular, the
coating can have a dark base layer and an optically variable layer arranged
over the
dark base layer, whereby the optically variable layer contains optically
variable
pigments, in particular interference-layer pigments or pigments produced on
the basis
of liquid-crystal polymers.
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[0033] According to a second preferred embodiment, a security element which
has
a substrate with at least one opening, whereby the opening is closed on one
side with
an at least partly translucent or transparent foil, is produced by applying a
coating to a
substrate provided with a through opening, in the region of the opening, so
that the
coating is not present, or substantially not present, within the opening, and
applying an
at least partly translucent foil to the side of the substrate opposing the
coating, so that
the opening is closed on one side with the at least partly translucent or
transparent foil
and the coating is arranged on the substrate substantially in the region of
the foil area.
[0034] The opening in the substrate can, as described above, be formed in the
substrate by methods such as punching or cutting, in particular laser cutting.
Likewise,
the opening can already be formed in the substrate during the production of
the
substrate, e.g. during the paper production.
[0035] The application of the coating to the substrate provided with a through
opening is preferably carried out in exact register, e.g. by applying a
coating or a foil
to the substrate over the entire area and thereafter removing it in the region
of the
through opening by means of laser ablation. Likewise, a coating can be applied
to the
substrate in exact register by printing, in particular by a gravure,
flexographic, screen,
offset or transfer printing method.
[0036] As the substrate, the coating and the at least partly translucent or
transparent
foil, the above-mentioned substrates, coatings and foils described in
connection with
the first preferred embodiment are respectively employable, so that the above-
mentioned details will not be repeated here.
[0037] In a variant of the hereinabove described second preferred embodiment,
the
coating can also be applied after the foil lamination.
[0038] In the individual embodiments, the coating respectively applied to the
substrate can preferably cover the entire substrate side, so that the
substrate is covered
with the coating substantially over the full area. Through the substantially
full-area
covering of the substrate, the wave formation of the substrate can be
considerably
restricted.
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o
[00391 In the individual embodiments, the coating respectively applied to the
substrate can cover the substrate side continuously with approximately
constant layer
thickness. However, the coating can also be present in the form of a gridding,
e.g. in
the form of strips, provided that there is obtained the effect of the opposing
force to the
at least partly translucent or transparent foil on the side of the substrate
opposing the
coating.
[00401 The invention will be made clear with reference to the following
implementation variants or examples in connection with the supplementary
figures.
[00411 The representations in the figures are strongly schematized for the
sake of
better comprehension and do not reflect the actual conditions. In particular,
the
proportions shown in the figures do not correspond to the relations existing
in reality
and serve exclusively to improve the clearness. Furthermore, the embodiments
described in the following examples are reduced to the essential core
information for
the sake of clarity. In the practical implementation, substantially more
complex
patterns or images can be used.
[00421 Specifically, the figures show schematically in a side view:
Fig. 1 a security element according to the invention with a substrate with an
opening which is closed on one side with an at least partly translucent or
transparent foil, whereby there is located on the side of the substrate
opposing the foil, in the region of the opening and substantially in the
region of the foil area, a coating which is not present, or substantially not
present, within the opening;
Fig. 2 a method for producing the security element from Fig. 1, wherein a
through
opening is produced in the substrate and the coating applied to the substrate,
and subsequently an at least partly translucent foil is applied to the side of
the substrate opposing the coating, so that the opening is closed on one side
with the at least partly translucent or transparent foil and the coating is
arranged on the substrate substantially in the region of the foil area;
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,
Fig. 3 a further method for producing the security element from Fig. 1,
wherein a
coating is so applied to a substrate provided with a through opening that the
coating is not present, or substantially not present, within the opening and
subsequently an at least partly translucent or transparent foil is applied to
the side of the substrate opposing the coating, so that the opening is closed
on one side with the at least partly translucent or transparent foil and the
coating is arranged on the substrate substantially in the region of the foil
area.
[00431 Fig. 1 shows a security element 1 according to the invention which has
a
substrate 2 with an opening 3, whereby the opening 3 is closed on one side
with an at
least partly translucent or transparent foil 4, and a coating 5 is located on
the side of
the substrate 2 opposing the foil 4, in the region of the opening 3 and
substantially in
the region of the foil area. Within the opening 3 the coating 5 is not present
or
substantially not present. In the region of the opening 3 the at least partly
translucent
or transparent foil 4 preferably has a translucent region. In particular, it
is preferred
that the at least partly translucent or transparent foil 4 has a transparent
region in the
region of the opening 3.
[00441 Fig. 2 shows a method for producing the security element 1 from Fig. 1.
As
shown in Fig. 2a, a coating 5 is first applied to one side of the substrate 2.
In a
subsequent step shown in Fig. 2b, a through opening 3 is produced by punching
or
(laser) cutting in the substrate 2 and the coating 5 applied to the substrate.
Subsequently, according to Fig. 2c, an at least partly translucent or
transparent foil 4 is
applied to the side of the substrate 2 opposing the coating 5, so that the
opening 3 is
closed on one side with the at least partly translucent or transparent foil 4
and the
coating 5 is arranged on the substrate 2 substantially in the region of the
area of the
foil 4.
[00451 Alternatively, the security element 1 of the invention can be produced
according to the method shown in Fig. 3. As shown in Fig. 3a, a substrate 2
provided
with a through opening 3 is first made available. A coating 5 is so applied to
the
substrate 2 in the region of the opening 3 that the coating is not present, or
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%
substantially not present, within the opening 3 (Fig. 3b). Subsequently,
according to
Fig. 3c, an at least partly translucent or transparent foil 4 is applied to
the side of the
substrate 2 opposing the coating 5, so that the opening 3 is closed on one
side with the
at least partly translucent or transparent foil 4 and the coating 5 is
arranged on the
substrate 2 substantially in the region of the area of the foil 4.
[00461 In a variant to the method shown in Fig. 3 for producing the security
element of the invention, the foil 4 is first applied to the substrate 2
provided with the
opening and subsequently the coating 5 is so applied to the substrate 2 that
no, or
substantially no, coating is present within the opening 3, the opening 3 is
closed on
one side with the at least partly translucent or transparent foil and the
coating is
arranged on the substrate 2 substantially in the region of the area of the
foil 4.
