Field
[0001] The present disclosure relates to a decorative and/or information containing label
comprising one or more emblems and a method for manufacturing it. The present disclosure
also relates to a precursor of said label obtained during said method of the present
disclosure.
Background
[0002] EP 0,911,786 discloses a laser markable label comprising a polymer layer which includes an addition
for reversible optical labelling, the additive being made recognizable, and especially
visible, by means of electron beams, X-rays, in particular by visible light and, very
particularly by IR or UV radiation. The polymer layer may also comprise an additive
suitable for reversible magnetic or electrical labelling. Emblems such as logos or
bar codes can be introduced into this layer by partially ablating the cover layer
with a laser beam. This partially destroys the exposed surface of the layer which
tends to make the label less durable and mechanically stable. Also, incorporating
the emblems requires an additional laser ablation step which may be less desirable
from a manufacturing point of view.
[0003] EP 0,688,678 discloses a single-layer laser label comprising
- a) a support layer which
- b) contains an additive which changes colour under laser irradiation and which
- c) is coated on one side with a self-adhesive composition which
- d) is optionally covered with a release paper or a release film.
[0004] This label requires the use of special pigments such as copper hydroxid phosphate
pigments or specific pearlescent pigments which when irradiated with a laser show
a colour change. The limited versatility of the label of EP '678 is not acceptable
for many applications. The formation of the emblems requires an additional laser irradiation
step subsequent to the manufacturing of the label which may not be desirable from
a manufacturing point of view. Also, laser irradiation tends to damage the exposed
surface of the label which may adversely affect its mechanical properties and durability.
[0005] EP 0,755,776 discloses a multilayer film, comprising a cover layer bearing on one side a damagable,
in particular a destructible or irreversibly deformable or permanently distortable
layer, and an adhesive layer for bonding with a substrate, whereby the sequence of
the damageable layer and the adhesive layers may be reversed, wherein the damageable
layer exhibits a three-dimensional pattern imparting a three-dimensional verification
marking to the film, and wherein the film shows an intralayer failure when being peeled
from the substrate.
[0006] In one aspect, the present disclosure provides a decorative and/or information containing
label comprising one or more emblems which is highly versatile and may comprise a
broad range of pigments and dyes. In some embodiments, the decorative and/or information
containing label does not require an additional laser ablation step to provide one
or more emblems and/or which has advantageous mechanical properties and/or provide
an aesthetically pleasing surface appearance. In another aspect, the present disclosure
provides an advantageous method of manufacturing such label.
Summary
[0007] The present disclosure relates to a precursor of a label comprising a release carrier
with a release surface bearing a polymer layer and a discontinuous emblem layer comprising
at least one emblem at the interface between the release surface and a major surface
of the polymer layer wherein the emblem is a three-dimensional section arranged within
the polymer layer (3) which is visually discernible from the polymer layer. The release
surface of the release carrier and/or the materials of the polymer layer and the emblem
layer are selected so that the cohesive force of the polymer layer, the cohesive force
of the one or more emblems and the bonding force between the one or more emblems and
the polymer layer is higher than the interfacial adhesive force between the polymer
layer and the emblems, respectively, and the release surface. A surface portion of
such emblem(s) contacts the release surface so that such surface portion of the emblem(s)
5 is coplanar with the adjacent exposed surface of the polymer layer. This results
in the label which comprises the polymer layer and the emblem layer, being essentially
cleanly separatable from the release surface when peeling off the release carrier.
[0008] The present disclosure furthermore relates to a label comprising a polymer layer
comprising one or more emblems arranged adjacent to one of the major surfaces of said
polymer layer, said emblems being three-dimensional sections arranged within the .polymer
layer adjacent to the surface of the polymer layer so that a surface portion of such
emblem is coplanar with the surface of the polymer layer and wherein the emblem is
visually discernible from the polymer layer, said emblems further comprising one or
more polymers and one or more colouring agents selected from the group consisting
of inorganic pigments including metal flakes, organic pigments, inks and dyes, and/or
one or more inorganic microspheres or beads whereby said colouring agents and/or inorganic
microspheres or beads and/or their respective concentration are selected so that the
one or more emblem(s) are visually discernible from the polymer layer. In some embodiments,
the label bears on its other major surface an adhesive layer such as, in particular,
a pressure-sensitive adhesive layer.
[0009] The present disclosure further relates to a method of making the precursor of a label
comprising the steps of
- (i) providing a release carrier,
- (ii) applying a discontinuous emblem layer comprising one or more emblems to the release
surface of the release carrier, and
- (iii) applying the polymer layer onto the release surface and the emblem layer so
that the emblem layer is arranged at the interface between the polymer layer and the
release surface of the release carrier
wherein the emblem is a three-dimensional section arranged within the polymer layer
which is visually discernible from the polymer layer.
[0010] The present disclosure furthermore relates to a method of making a label according
to the invention comprising the steps of
- (i) providing a precursor of the present invention, and
- (ii) removing the release carrier.
Brief Description of the Drawings
[0011]
Fig. 1 shows one embodiment of a precursor 2 of the present disclosure comprising a release
carrier 6, a polymer layer 3 and a discontinuous emblem layer 4 comprising several
emblems 5 at the interface between the release surface 6a and the major surface 3a
of the polymer layer 3. The surface of the emblem(s) 5 facing the release surface
6a is coplanar with the surface 3a of the polymer layer 3.
Fig. 1a shows one embodiment of a label 1 of the present disclosure which is obtainable from
the precursor 2 of Fig. 1 by removing the release carrier 6. Optionally a protective
layer 10 may be applied onto the major surface 3a of the polymer layer 3 (not shown).
Fig. 2 shows another embodiment of a precursor 2 of the present disclosure which is based
on the precursor 2 of Fig. 1a but additionally comprises an adhesive layer 7 attached
to the surface 3b of the polymer layer 3. The adhesive layer 7 is covered with release
liner 9.
Fig. 2a shows another embodiment of a label 1 of the present disclosure which is obtainable
from the precursors 2 of Fig. 2 by removing the release carrier 6. Optionally a protective
layer 10 may be applied to the major surface 3a of the polymer layer 3 (not shown).
Detailed Description
[0012] The term "label" as used above and below denotes a spatially limited section of a
one- or multilayer continuous polymeric film optionally including an adhesive layer
such as, in particular, a pressure-sensitive adhesive layer. The label can be obtained
from such polymeric film. The polymeric film may comprise only one polymeric layer
3 comprising one or more emblems 5 arranged adjacent to major surface 3a of the polymer
layer 3 and no further polymeric layers, or it may comprise one or more polymeric
layers 8 in addition to polymeric layer 3. The label can be obtained from such continuous
polymeric film by converting using conventional techniques such as, for example, die-cutting.
The label can have different lengths and includes, for example, products with a relative
short length such as identification or price tags or decorative and/or information
providing tabs but also tape products with a relative great length sufficient for
winding them into a roll.
[0013] The term "emblem" as used above and below denotes a three-dimensional section which
is arranged within the polymer layer 3 adjacent to the surface 3a of the polymer layer
3. In the precursor 2 the one or more emblems 5 are arranged so that a surface portion
of such emblem(s) 5 contacts the release surface 6a whereby such surface portion of
the emblem(s) 5 is coplanar with the exposed adjacent surface 3a of the polymer layer
3. This is also referred to above and below as the emblem layer 4 and/or the emblem(s)
5 being arranged at the interface between the surface 3a of the polymer layer 3 and
the release surface 6a of release carrier 6. The one or more emblems are visually
discernible against the surrounding polymer layer 3, and are preferably arranged to
provide a decorative or aesthetical effect such as figures or symbols and/or to deliver
information such as, for example, an instruction, warning or identification information.
[0014] The precursor 2 of a decorative and/or information containing label 1 of the present
disclosure comprises a release carrier 6 which, in some embodiments, comprises a carrier
film or layer such as a paper or polymer film bearing a low-adhesion release layer
to provide a release surface 6a allowing for an essentially residue-free removal of
the release of the polymer layer 3 embedding emblem(s) 5, from the release surface
6a. Representatives of suitable carrier films or layers comprise, for example, high-density
papers such as glassine paper, clay-coated paper, kraft paper, polymer-laminated paper
such as polyethylene-laminated paper and polymeric films. Useful polymeric films and
layers include, for example, polyolefin polymers, monoaxially oriented polypropylene
(MOPP), biaxially oriented polypropylene (BOPP), simultaneously biaxially oriented
polypropylene (SBOPP), polyethylene, copolymers of polypropylene and polyethylene,
polyester polymers, polycarbonate polymers, polymethacrylate polymers, cellulose acetate,
polyester (e.g., biaxially oriented polyethylene terephthalate), vinyl acetates, and
combinations thereof.
[0015] The low-adhesion release layer may, for example, be coated onto the carrier film
or layer followed by subsequent drying and/or UV or e-beam curing. Examples of suitable
low adhesion coatings are cellulose acetate butyrate, vinyl acetate-dibutyl maleate,
vinyl alcohol silicone emulsions, or preferably water-based ethylene acrylic acid
or water-based acrylic. The carrier films or layers may also be treated with release
agents such as fluorine containing resins or silicone resins. Alternatively, it is
also possible to apply a printable low-adhesion coating as is described, for example,
in
U.S. Pat. No. 5,496,635.
[0016] In case the release carrier 6 itself comprises a release material such as, for example,
a highly fluorinated polymer it is also possible to omit the low-adhesion release
layer and employ the carrier layer alone.
[0017] The precursor 2 of the decorative and/or information providing label 1 furthermore
comprises a discontinuous emblem layer 4 comprising one or more emblems 5. The term
"discontinuous" means in case only one emblem is present, that such emblem 5 covers
only part (preferably less than 50 %) of the release surface 6a. In case two or more
emblems 5 are present the term "discontinuous" means that the two or more emblems
are not linked to each other but form discrete, separate sections. The two or more
emblems 5 preferably cover less than 75 % and more preferably less than 50 % of the
release surface 6a.
[0018] In some embodiments, the emblems layer 4 is applied by printing a printable or coatable
precursor of the emblems 5 onto the release surface 6a with subsequent drying and/or
curing. The printable or coatable precursor of the emblems preferably has a Brookfield
viscosity of between 300 cPoise and 8,000 cPoise and more preferably between 300 and
3,000 cPoise at a temperature of 20 °C. The precursor of the emblems may be applied
by any printing method such as, for example, by screen printing, ink-jet printing,
electrostatic printing or rotogravure printing, flexo printing, letterpress printing,
offset printing or thermal transfer or hot stamping printing.
[0019] The printable or coatable precursor of the emblem(s) 5 comprises one or more polymers
which are selected to allow for an essentially clean and residue-free removal of the
emblems 5 together with the surrounding matrix of polymer layer 3 from the release
surface 6a when removing the release carrier 6 to provide the label 1. In some embodiments,
the polymers of such precursor of the emblem are selected from a group of polymers
consisting of (meth)acrylate polymers, polyurethane polymers, polyamide polymers,
polystyrene polymers, polymers comprising polymerized units derived from one or more
olefin monomers, from one or more (meth)acrylic monomers, from one or more vinyl monomers,
silicone polymers, and mixtures thereof.
[0020] Representative examples include polyolefins such as polyethylenes, polypropylenes
and polybutylenes; olefinic copolymers such as ethylene(meth)acrylate copolymers;
ethylene/vinyl acetate copolymers; acrylonitrile-butadiene-styrene copolymers; acrylic
polymers and copolymers, polyurethanes and copolymers such as acrylic polyurethanes;
vinyl polymers and copolymer such as polyvinylchloride, and mixtures thereof. Mixtures
or blends of any plastic or plastic and elastomeric materials such as polypropylene/polyethylene,
polyurethane/polyolefin, polyurethane/polycarbonate, polyurethane/polyester can also
be used.
[0021] In some embodiments, the acrylic polyurethane may be the acrylic polyurethane which
is disclosed in
WO 93/12155 and comprises components A, B and C wherein component A comprises a copolymer of
- (i) a monoester of acrylic or methacrylic acid and an aliphatic diol having 2 to 8
carbon atoms, and
- (ii) an ester of acrylic or methacrylic acid and an aliphatic alcohol having 1 to
8 carbon atoms, and optionally a vinyl aromatic monomer as well as N-vinylpyrrolidone
or N-vinylcaprolactame,
said component A having a TG of 30 ° C to 100 °C,
component B comprises an aliphatic polyester diol with an weight-average molecular
weight less than 20,000, and
component C comprises a polyfunctional isocyanate or blocked polyfunctional isocyanate.
[0022] This polymer is described in more detail on page 5, line 4 - page 7, line 14 of
WO 93/12155 which passage is enclosed herein by reference.
[0023] The precursor of the emblem(s) 5 furthermore comprises one or more additives which
render the emblem(s) 5 visually discernible from the polymer layer 3. Such additives
comprise, in particular, colouring agents such as inorganic pigments including metallic
pigments or metallic flakes such as aluminium flakes or particles, organic pigments,
water-borne or solvent-borne inks or dyes, and/or inorganic microspheres and/or beads
such as, for example, glass beads. These additives may be selected so that the emblem(s)
5 are visually discernible from the surrounding polymer layer 3 by the unaided eye
under normal ambient light conditions but it is also possible that the additives are
selected so that the emblem(s) 5 are visibly discernible when viewing them through
magnifying glasses or a microscope, respectively, or upon irradiating the label 1
with UV light, IR light or viewing it under retroreflective lighting conditions. It
was found that emblem(s) comprising partially metallized glass beads or a combination
of glass beads which may or may not be metallized, with metal flakes exhibit retroreflective
properties. The term "partially metallized glass beads" refers to glass beads 20 -
60 % of the surface of which are coated with a thin metal film which may be applied,
for example, by CVD or PVD techniques. The use of glass beads which may or may not
be aluminized in combination with aluminium and/or silver flakes or particles is preferred.
Glass beads suitable in the present invention are preferably essentially spherical
and typically have a diameter of between 40-60 micrometers (µm).
[0024] Inorganic pigments which are suitable include, for example, titanium dioxide white,
carbon and vegetable black, iron oxide pigments, cadmium pigments, lead chromate pigments,
chromium oxide pigments including chromium oxide green, ultramarine blue, chrome green,
phthalo chrome green, mixed metal oxide pigments and bi-vanadates.
[0025] Organic pigments which are suitable include, for example, azo pigments, polycyclic
pigments and metal complex pigments. Suitable azo pigments include, for example, monoazo
yellow and orange pigments, disazo pigments, naphthol pigments, benzimidazolone pigments
and disazo condensation pigments.
[0026] Suitable polycyclic pigments include, for example, phthalocyanine pigments, quinacridone
pigments, perylene and perinone pigments, thioindigo pigments, anthraquinone pigments,
dioxazine pigments, isoindolinone and isoindoline pigments, diketopyrrolo pyrrole
pigments, triarylcarbonium pigments and quinophthalone pigments.
[0027] Commercially available inorganic pigments which are suitable for use in the emblem(s)
5 include, for example, carbon black available as carbon black paste from Degussa,
Germany. As a white coloured pigment, titanium dioxide in silane modified form can
be used (Kronos CL 310, Kronos Titan, Leverkusen, Germany). Lead sulfo-chromate pigments
and mixed crystal lead sulfo-chromate-molybdate pigments are available from Heubach
as Heucotron T and Heucotron T Orange 8010, respectively. Also aluminium particles
of 5 µm length in a solvent (STAPA-Off-Set 3000, Eckhart-Werke, Fürth, Germany) can
be used as organic pigments.
[0028] Commercially available organic pigments include isoindolininone yellow commercially
available as Cromophtal Yellow 2RLTS from Ciba; perylene red commercially available
as Irgazin Red BPTN from Ciba; pthalocyanine green, a halogenated Cu-phtalocyanine
commercially available as Chomophtal Green GFN from Ciba; quinacridone violet commercially
available as Cinquasia Violet RRT-899D from Ciba; C. I. pigment red 178/71155 (Paliogen
rot L3910 HD, BASF, Ludwigshafen, Germany); C. I. pigment yellow 110 (Irgazin gelb
3RLT-N, Ciba-Geigy, Marienberg, Germany); and C. I. pigment blue 1511, Heliogen blau
K6911D, BASF, Ludwigshafen, Germany).
[0029] Pearlescent pigments that subtly change colour as the viewing angle is changed can
be obtained, for example, from Merck KGaA, Darmstadt, Germany, under the Iriodin trade
designation.
[0030] Liquid crystal polymer additives which change colour when the viewing angle is changed
are also suitable and can be obtained from, for example, Wacker Chemie of Munich,
Germany.
[0031] It is also possible to use up-converting pigments, down-converting pigments or a
combination thereof.
[0032] Down-converting pigments are pigments that emit UV light upon absorption of light
from the visible spectrum. These may be organic or inorganic. Inorganic as referred
to herein means the pigment may be entirely inorganic or it may contain inorganic
compounds complexed by organic compounds (e.g. chelates etc). Preferred are down-converting
pigments having an average particle size greater than 1 µm or greater than 1.5 µm.
An example of a down converting additive which is invisible under ambient light but
visible under UV light is Black Light Varnish available from Wernecke of St. Paul,
MN, USA. It is also possible to use S. A. Other examples are fluorescent or phosphorescent
pigments such as rare earth metals or rare earth metal oxides, e.g. neodymium oxides.
A suitable fluorescent pigment is available from Honeywell under the trade designation
Lumilux® Effect Blue SN. It is also possible to use Examples of phosphorescent pigments
include the Lumilux® Phosphorescent pigments series available from Honeywell such
as Luminux® green SN-F5, Lumilux® Green N5 or Lumilux ® C-Pigments.
[0033] Exemplary up-converting (anti-stoke's) pigments are materials capable of emitting
electromagnetic radiation of greater energy upon absorption of electromagnetic radiation
of lower energy. For example, the up-converting pigments may be capable of absorbing
infrared radiation and emitting radiation in the visible spectrum (e.g. from about
400 nm up to less than 700 nm wavelength), e.g. pigments that emit green light upon
irradiation with infrared light (e.g. radiation of from about 700 to about 1300 nm
wave length). It is also possible to use an up-converting pigment which is excited
by electromagnetic radiation of the visible spectrum and emits UV light (e.g. radiation
of a less than 400 nm up to less than 250 nm wave length).
Up-converting pigments are typically inorganic materials doped with erbium (Er), yterbium
(Yb) or thulium (Tm), such as for example rare earth metal fluorides doped with rare
earth metals or metal ions, such as for example Yb3+, Er3+, Tm 3+, Nd3+, Ho3+, although
crystals doped with ions of some transition metals, e.g. Ti2+, Ni3+, Mo3+ or Re4+
have also been used in the fabrication of up-converting pigments. Typical examples
of up-converting pigments correspond to the general formula NaLnF4: Yb3+, Er3+ with
Ln typically being Y, Gd or La. A particular example is NaY0.57,Yb0.39, Er0.39F4.
Other examples include oxysulfide doped with rare metals corresponding to the general
formula M2O2S: Yb, Tm, Er with M being a lanthanoid or Y, Sc such as for example Gd2O2S:
Yb, Tm, Er or Y2O2S2: Yb, Tm, Er. Other examples of crystals that may be doped with
such ions include manganese halides and tungstate crystals such as RbMnCl3, CsMnCl3,
CsMnBr3, Rb2MnCl4 or NaY(WO4)2. Examples of suitable up-onverting nanopowders include
Al2O3 or yttrium aluminium garnet doped with Nd3+ or Ce3+. Preferably, the up-converting
pigments are crystalline.
[0034] Inks which are suitable in the present invention include 3M Process Colour Series
8801 which is commercially available from 3M Company.
[0035] The average size of the colouring agents can vary widely. Organic pigments typically
have an average size of between 0.03 -1 µm or between 0.03 - 3 µm or between 0.05
- 0.5 µm. The average size of inorganic pigments can vary between 0.2 µm to 50 µm
or even more. Titanium dioxide, for example, has a size of typically between 0.2 -
1 µm whereas red iron oxide has typically has an average size of between 0.3 - 3 µm.
The average size of metal particles and flakes typically is between 3 - 25 µm, and
glass beads have a typical average size of 40 - 60 µm. The person skilled in the art
will easily select the appropriate thickness of the polymer layer 3 and of any additional
polymer layers 8, if present, in view of the respective average size of the colouring
agents used.
[0036] In one embodiment of the invention that has a particular favourable migration behaviour
of the pigments even after heat treatment above 80°C for one hour (i.e. low or no
migration into adjacent layers), the pigments used have a particle size of greater
than 1 µm or greater than 1.5 µm for the preferred layer thicknesses as described
herein.
[0037] In one embodiment the colouring agents and/or inorganic microspheres or beads used
are preferably selected so that the one or more element(s) 5 are visibly discernible
against the polymer layer 3 upon formation of the precursor 2, i.e. without requiring
a further treatment step such as an additional irradiation source other than visible
light.
[0038] In another embodiment, the colouring agents and/or inorganic microspheres or beads
used in the present invention, are preferably selected so that the one or more element(s)
5 are visibly discernible against the polymer layer 3 upon formation of the precursor
2, that is, without requiring a further treatment step such as laser irradiation.
Therefore the use of colouring agents which exhibit a colour change upon i.e. upon
irradiation with an energy source other than visible light, e.g. UV light (e.g. down-converting
pigments) IR-light (e.g. up-converting pigments) or laser marking such as the Lazerflair®
pearlescent pigments from Merck.
[0039] In some embodiments, the one or more additives included into the precursor of the
emblem(s) 5 to render such emblem(s) visually discernible against the polymer layer
3 are present in an amount of from 2 - 70 pph, and, in some embodiments, 2-50 pph
(parts per hundred resin) with respect to the mass of such precursor.
[0040] The precursor of emblem(s) 5 may comprise further agents and additives such as, for
example, levelling agents, thickeners, wetting agents, polymerization catalysts, crosslinking
agents and solvents. Levelling agents support the formation of a uniform and smooth
surface without surface defects. Suitable levelling agents are generally organic silicones
and fluorochemicals. Thickeners and solvents may be added in order to adjust the viscosity
of the precursor of the emblem(s) 5 to impart advantageous printability properties
to it. Polymerization catalysts and, optionally, crosslinking agents may be added
if the precursor is cured subsequent to its application to the release surface.
[0041] While the structure of that part of the surface of the emblem(s) 5 which is or has
been in contact with the release surface 6a is determined by the surface structure
of the release surface 6a and preferably is essentially flat, the shape of the other
surface portions of the emblem(s) 5 which are in contact with the polymer layer 3,
can vary broadly and can be, for example, essentially polygonic or essentially curved.
The average height of the emblem(s) which is defined as the average distance between
the release surface 6a and the maximum extension of the emblem(s) 5 in a direction
normal to such release surface 6a is, in some embodiments, less than the thickness
of the polymer layer 3; in some embodiments, less than 90 %; and in some embodiments,
less than 50 % of the thickness of the polymer layer 3. In case of glass beads or
pearlescent pigments, for example, which may have an extension of, for example, 40-80
µm the average height of the emblem(s) may exceed the thickness of the polymer layer
3; in such case one or more further polymer layers 8 are required, and the emblem(s)
5 extend in such additional polymer layers 8.
[0042] The extension and shape of the emblem(s) 5 in the plane of surface 3a of the polymer
layer 3 can vary broadly and is determined by the desired decorative effect or the
information to be displayed. Emblem(s) 5 which are visible and discernible with the
unaided eye typically have an extension in the plane of surface 3a of at least 1 mm.
Emblem(s) 5 with an extension in the plane of surface 3a of, for example, 10 - 500
and, in some embodiments, 25 -250 µm are typically not readily discernible with the
unaided eye but require the use of, for example, magnifying glasses or a microscope.
Therefore such emblem(s) having an extension in the µm-range, can be used as a security
feature which is referred to below in the Example section as "microscript"-type emblem(s)
5.
[0043] The precursor 2 of the decorative and/or information providing label 1 furthermore
comprises a polymeric layer 3 which is attached to the release surface 6a of the release
carrier thereby enclosing the one or more emblem(s) 5. In some embodiments, a precursor
of the polymer layer 3 is laid down onto the release surface 6a by printing or coating
or casting methods such as, for example, screen printing, spraying, rotogravure or
knife coating. It is also possible to apply the polymer layer 3 by extrusion, lamination,
calendaring, or thermal transfer printing or hot film stamping. The printable and/or
coatable precursor of the polymer layer 3 preferably has a Brookfield viscosity of
between 300 cPoise and 8,000 cPoise and more preferably of between 300 and 3,000 cPoise
at 20 °C. Subsequent to its application to the release surface 6a and the emblem(s)
5, the precursor of the polymer layer may be dried and/or cured. Drying may be applied,
in particular, to waterborne precursors of the polymer layer using a drying temperature
of, for example, 20 - 200 °C. Curing may be effected, for example, by irradiating
the precursor of the polymer layer 3 with UV light or by increasing its temperature
to accelerate curing.
[0044] The printable or coatable precursor of the polymer layer 3 comprises one or more
polymers which are selected
- to provide a sufficiently strong bond to the emblem(s) 5, and
- to allow for an essentially clean removal of the polymer 3, together with the emblem(s)
5, from the release surface 6a when removing the release carrier 6
so that the label 1 can be separated essentially intactly and cleanly from the release
surface 6a of the release carrier. The precursor of the polymer layer 3, the precursor
of the emblem(s) 5 and/or the release surface 6a are therefore selected so that the
interfacial adhesive force between the polymer layer 3 enclosing the emblem(s) 5 and
the release surface 6a is less than the cohesive strength of the polymer layer 3,
the cohesive strength of the emblem(s) 5 and the bonding strength between the polymer
layer 3 and the emblem(s) 5.
[0045] The requirement of a sufficient bonding strength between the polymer layer 3 and
the emblem(s) 5 can usually be met by selecting the precursor of the polymer layer
3 so that it is compatible with the polymer of the emblem(s) 5 and its precursor.
The term "compatible" means that the precursors of the polymer layer 3 and of the
emblem(s) are selected so that they are chemically similar to each other and can react
to form a chemical bond. If the precursor ofthe polymer layer 3 comprises, for example,
a polymer comprising unsaturated carbon-carbon double bonds or acrylic groups the
precursor of the emblem(s) 5 preferably also comprises a polymer comprising such groups.
Such a choice can be made easily and does not require any inventive input from the
person skilled in the part.
[0046] The precursor of polymer layer 3 comprises one or more polymers which are preferably
selected from the group of polymers given above for the polymers suitable to use in
the emblems. Especially preferable are acrylic based and polyvinyl based polymers.
[0047] In some embodiments, the precursors of the polymer layer 3 and the one or more emblem(s)
5 each comprise at least one polymer which is essentially the same.
[0048] In some embodiments, the polymers used on the precursors of the polymer layer 3 and
the emblem(s) 5 are selected so that the polymer layer 3 of the label 1 with the emblem(s)
5 enclosed therein, has a tensile strength at break of about 1,000 N/cm
2 to about 5,000 N/cm
2 and, in some embodiments, from about 1,250 N/cm
2 to 4,000 N/cm
2. The elongation at break of the polymer layer 3 preferably is between 2 - 50 %. The
polymer layer 3 preferably has a thickness of between 5 - 500 µm and more preferably
between 20 - 250 µm.
[0049] The precursor of the polymer layer 3 may comprise further additives such as colouring
agents such as inorganic and organic pigments, inks and dyes, inorganic or organic
microspheres, glass beads, levelling agents, thixotropic agents, thickeners, wetting
agents, polymerization catalysts, crosslinking agents and solvents.
[0050] If colouring agents and/or microspheres are added to the precursor of the polymer
layer 3 these additives and/or their concentration are selected to be different from
the colouring agents and/or microspheres or their concentration, respectively, used
in the emblem(s) 5 so that the emblem(s) 5 are visually discernible against the polymer
layer 3 enclosing such emblem(s) 5. For the purposes of the present disclosure colouring
agents such as the Lazerflair® pearlescent pigments from Merck which change their
colour upon laser irradiation, are considered to be the same pigment before and after
the laser irradiation. The In one embodiment of the invention the labels 1 of the
present disclosure preferably comprise a colouring agent which exhibits a colour change
when irradiated with an IR-light source, (such as an IR laser beam) or a UV light
source under conditions which essentially do not result in damaging the surface 3a
of the polymer layer. In another embodiment of the invention the labels 1 of the present
invention preferably comprise a colouring agent which exhibits a colour change without
irradiation with an IR-light source, (such as an IR laser beam) or a UV light source.
[0051] In the label of the present invention the total concentration of the colouring agents
in the emblem(s) 5 is different from the total concentration of the colouring agents
in the polymer layer (3).
[0052] In some embodiments, the precursor of the polymer layers 3 comprises partially metallized
glass beads or optionally non-metallized glass beads in combination with metal flakes
or particles to impart retroreflective properties to the polymer layer.
[0053] The variation of the colourants and/or microspheres and/or their concentration, respectively,
in and adjacent to the surface 3a of the polymer layer 3 is a unique feature of some
embodiments of the precursor 2 and the corresponding label 1 obtainable from such
precursor. This construction allows for a broad variety of design possibilities without
placing restrictions on the nature of the colourants and/or microspheres used which
is required, for example, in
EP 0,688,678.
[0054] In some embodiments, the precursor 2 of label 1 comprises an adhesive layer 7 so
that the label 1 can be adhesively attached to substrates. The adhesive layer may
be attached to the surface 3b of the polymer layer 3 (i.e., to the major surface of
the polymer layer which is opposite to the major surface 3a and to the emblem layer
4) or, if the precursor 2 and the corresponding label 1 comprise further polymer layers
8 which are attached to the surface 3b of the polymer layer, to the exposed surface
of such layer or stack of layers.
[0055] The adhesive layer 7 may be applied onto the polymer layer 3 (or the exposed outside
layer of the precursor) by casting from an organic solution or an aqueous dispersion
or by such techniques as hot melt coating. The adhesive layer 7 may also be obtained
by laminating an adhesive film onto the polymer layer 3 or the outside layer of the
precursor, respectively. Examples of suitable adhesive films include 3M Transfer Tape
9458 (thickness 25.4 µm, suitable for application to smooth surfaces) and 3M VHB 4918,
clear (thickness 2.0 µm, suitable for application to rough surfaces). To promote adhesion
between the polymer layer 3 (or the outside layer of the precursor) and the adhesive
layer 7, surface 3b of the polymer layer 3 (or the outside layer of the precursor)
can be treated before the adhesive is applied. This treatment can comprise the application
of a chemical primer or preferably include corona discharge treatment.
[0056] For making the adhesive layer 7, it may be preferred to use pressure-sensitive adhesives
or heat-activatable adhesives. These may comprise polyacrylates, polyesters, polyimides,
polyolefins, polyamides, polyurethanes, silicone polymers, polybutadiene and copolymers,
polyisoprenes and copolymers, natural and synthetic rubbers as well as hydrogenated
derivates thereof with and without resins, fillers and crosslinking agents.
[0057] Polyacrylates have also proven to be useful, particularly those which have been modified
for use on a variety of surfaces exhibiting very different surface energies, such
as steel and polyethylene. Useful alkyl acrylates (i.e., acrylic acid alkyl ester
monomers) for the preparation of polyacrylates include linear or branched monofunctional
unsaturated acrylates or methacrylates of non-tertiary alkyl alcohols, the alkyl groups
of which have from 4 to 14 and, in particular, from 4 to 12 carbon atoms. Examples
of these lower alkyl acrylates include but are not limited to, n-butyl acrylate, isobutyl
acrylate, hexyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, n-octyl acrylate,
n-octyl methacrylate, 2-methylbutyl acrylate, isononyl acrylate, n-nonyl acrylate,
isoamylacrylate, n-decyl acrylate, isodecyl acrylate, isodecyl methacrylate, isobornyl
acrylate, 4-methyl-2-pentyl acrylate and dodecyl acrylate.
[0058] In some embodiments, acrylate-based pressure-sensitive adhesive materials such as
copolymers of isooctyl acrylate and acrylic acid like those disclosed in
U.S. Pat. No. 2,884,126 (
U.S. Pat. No. Re: 24,906) may be used. The adhesive layer 7 can have a thickness of 10 to 2,000 µm, in some
embodiments, 10 to 1,000 µm.
[0059] In some embodiments, the pressure-sensitive adhesives are tackified or non-tackified
isooctyl acrylate and acrylic acid copolymers. The copolymers may be employed in amounts
ranging from 50 to 70 % and, in some embodiments, in an amount of about 60 % by weight.
As tackifying resin, there may be used, for example, Foral 85 (company Hercules),
a hydrogenated rosin or its glycerol or pentaerythritol esters in amounts of preferably
30 to 50 % and particularly preferred of about 40 % by weight. In the mixture of adhesive,
typically antioxidants in amounts of about 0.5 - 2 wt. % and cross-linkers such as
for example aziridine compounds may be added.
[0060] The adhesive layer 7 can be protected by a release liner 9. The release liner is
generally adhesive-repellant and may comprise paper or film which has been coated
or modified with compounds of low surface energy relative to the adhesive applied.
Organo silicone compounds, fluoropolymers, polyurethanes, polyethylene naphthalate
and polyolefins can serve this purpose. The release liner can also be a polymeric
sheet produced from polyethylene, polypropylene, PVC, polyesters with or without the
addition of adhesive-repellant compounds. The release liner can have a thickness of
25 to 250 µm, preferably 30 to 200 µm.
[0061] The one or more additional layers 8 which may be attached to the surface 3b of polymer
layer 3 may be polymer layers each comprising one or more polymers which may be selected
from a group of thermoplastic polymers consisting of polyesters, polycarbonates (e.g.
acrylonitrile butadiene styrene polycarbonate), polyarylates, polyamides, polyimides,
polyamide-imides, polyether-amides, polyetherimides, polyaryl ethers, polyarylether
ketones, aliphatic polyketones, polyphenylene sulphide, polysulfones, polystyrenes
and their derivatives, polyacrylates, polymethacrylates, cellulose derivatives, polyethylenes,
polyolefins, copolymers having a predominant olefin monomer, fluorinated polymers
and copolymers, chlorinated polymers, polyacrylonitrile (e.g. acrylonitrile styrene
acrylate), vinyl polymers such as polyvinylacetate, polyvinylchloride or polyvinylalcohol,
polyethers, ionomeric resins, elastomers, silicone resins, epoxy resins, and polyurethanes.
The layer 8 may have a thickness of from 10 to 500 µm.
[0062] In some embodiments, such additional polymer layer(s) 8 comprises one or more polymers
selected from the group of polymers identified above for use in polymer layer 3 and
in the emblem layer 4.
[0063] The additional layers 8 may be applied to surface 3b of polymer layer 3 by any conventional
technique including lamination, coating, printing or the like. The additional polymer
layers may comprise further additives such as colouring agents including inorganic
and organic pigments, inks and dyes, organic and inorganic microspheres and beads,
levelling agents, thixotropic agents, thickeners, wetting agents, polymerization catalysts,
crosslinking agents and solvents.
[0064] In one embodiment, precursor 2 and the corresponding label 1 comprise one or more
additional polymer layers. These one or more additional polymer layers 8 may comprise
one or more colouring agents (or colourants) which are different from and/or used
in a different concentration than the colourants used in the polymer layer 3 and/or
the one or more emblem(s) 5. This allows for specific decorative and/or aesthetical
effects including laser ablation of the polymer layer 3 to display the one or more
polymer layers 8 beneath layer 3. While this broadens the design possibilities made
available, laser ablation may not be preferred for any application because it damages
the surface of the label 1 which makes such label less mechanically durable.
[0065] In some embodiments, label 1, which is obtainable from the precursor 2 by removing
the release carrier 6, offers several advantages and unique properties.
[0066] The exposed surface of the label 1 may be formed by surface 3a of the polymer layer
3. The roughness and structure of surface layer 3a including the exposed surface of
the emblem(s) 5 is determined by the roughness and structure of the release surface
6a to which the polymer layer 3 and the emblem(s) 5 had been applied in the precursor
2.
[0067] Generally, the release surface 6a is essentially smooth resulting in an essentially
smooth surface 3a of the label 1. The term "essentially smooth" means that the release
surface 6a exhibits an average roughness R
Z of less than 5 µm and in some embodiments, of less than 3 µm. In some embodiments,
the average surface roughness R
Z is between 0.5 - 2.5 µm; and, in some embodiments, between 0.7 - 1.5 µm. Label 1
does not require a laser after-treatment to render the emblem(s) 5 visually discernible
against the polymer layer 3. Consequently, the surface portion of the emblem(s) 5
within such surface 3a is not damaged by any laser treatment, and the surface roughness
of the surface 3a and the surface portion of the emblem(s) 5 within such surface 3a
is preferably essentially the same.
[0068] For specific applications where the surface of the label should have, for example,
a leather-like look/surface appearance, the release surface 6a may be modified to
have a higher roughness R
Z of, for example, between 5 µm and 1,000 µm.
[0069] If desired, the release layer is structured and exhibits a regular or irregular pattern
of indentations and/or elevations as is described, for example, in
EP 0,951,518.
[0070] A protective layer 10 may be attached to the surface 3a of the polymer layer 3 of
the label to protect the label 1 and to impart, for example, scratch resistance to
it. In some embodiments, the protective layer 10 is transparent. Examples of suitable
materials for the protective layer of the invention include primed or unprimed polyethylene
terephthalate (polyester), polyvinylchloride, polyolefins, or cellulose acetate films.
While these protective films 10 are intended to protect the label permanently it is
also possible to apply, for example, a masking tape to the exposed surface of the
polymer layer for temporary protection.
[0071] Label 1 comprises a polymer layer 3 with emblem(s) 5 arranged adjacent to the surface
3a of such polymer layer 3 as is described above. In such label the polymer layer
3 and/or the emblem(s) 5 comprise one or more colourants and/or microspheres so that
the colourants and/or microspheres and/or their concentration, respectively, in the
polymer layer 3 on the one hand and in the emblem(s) 5 on the other hand are different
from each other. In other words, there is a variation of colourants and/or microspheres
and/or their respective concentration in the area of surface 3a of the polymer layer
3 and the emblem(s) 5 enclosed therein so that the emblem(s) 5 are visually discernible
against the polymer layer 3.
[0072] Label 1 is preferably made by manufacturing precursor 2 and removing the release
carrier 6. Removal of release carrier 6 is preferably obtained by peeling off the
release carrier.
[0073] If desired, a protective layer 10 may additionally be applied to the polymer layer
3 as was described above.
[0074] In some embodiments, the precursor is made by providing a release carrier 6 in the
first step. Then the emblem layer 4 comprising one or more emblems 5 is attached to
the release surface 6a, for example, by printing the precursor of emblem(s) 5 onto
the release surface 6a. The emblem(s) 5 may be dried and/or cured subsequent to such
printing step. Then the precursor of the polymer layer 3 is applied onto the release
surface 6a and the emblem(s) 5 so that the polymer layer 3 encloses the emblems. The
precursor of the polymer layer may be applied by coating, casting or printing using
any known coating and/or printing method. It is also possible to apply the polymer
layer 3 or its precursor, respectively, by extrusion, lamination, hot stamping or
thermal transfer printing. Then the precursor of the polymer layer 3 is dried and/or
cured. If desired, the precursor may be further modified by attaching one or more
further polymer layers and an adhesive layer 7 such as a pressure-sensitive adhesive
layer.
[0075] The present disclosure will be further illustrated in the following examples which
are to exemplify embodiments of the present disclosure without restricting them.
List of Materials
Component A:
[0076] Acrylate polyol comprising 2-hydroxyethyl methacrylate (2-HEMA), methylmethacrylate
(MMA), ethylmethacrylate (EMA) and iso-butylmethacrylate (IBMA), was prepared according
to the following procedure: 50 parts toluene and 50 parts butylacetate were charged
to a reaction vessel equipped with a nitrogen purge, stirrer, thermometer and addition
funnel. 2.5 parts di-t-butyl peroxide was added to the solvents at 60 °C. 100 parts
monomer mixture, comprising 16 parts 2-HEMA, 55 parts MMA, 17 parts EMA and 12 parts
IBMA, was mixed with 2.5 parts azobisisobutyronitrile. The monomer mixture was added
to the contents of the vessel with stirring in three equal portions: one portion initially,
one portion after 1 hour and one portion after 2 hours. After the exotherm was complete,
the reaction mixture was stirred at 60 °C for 8 hours. Final solids content was about
50 weight%.
Component B:
[0077] Aliphatic polyesterdiol: Epsilon-carpolactonediol, available under the trade-name
TONE® 230 (Union Carbide, USA)
Component C:
[0078] Blocked multifunctional isocyanate, adduct of 1,6-hexamethylene diisocyanate and
2-butanone oxime available under the trade name Desmodur BL 3175 (Bayer Leverkussen,
Germany)
Colouring agents (Component D):
[0079]
D1: titanium dioxide silane modified, commercially available under the trade name
Kronos CL310 (Kronos Titan, Germany)
D2: Aluminum particles in solvent, 5µ available under the trade name STAPA-OffSet
3000 (Eckhart-Werke, Germany)
D3: Carbon black paste in soya alkyd resin available under the trade name TACK 1 (Degussa,
Germany)
Component E (levelling agent):
[0080] 3M Novec™ Fluorosurfactant FC 4434
Acrylic coating mixture-1 (white):
[0081] The solution of acrylate polyol (component A; 59 weight %) as prepared above was
mixed with a 50 % by weight solution of aliphatic polyester diol (component B; 15
weight %) in toluene. Component D1 (30 parts per hundred resin pph) was added. The
resulting mixture was rendered homogeneous by mixing on a ball mill for eight hours
at room temperature.
[0082] Directly preceding the coating in the Examples (see below), blocked isocyanate (component
C; 26 weight %) was added as well as dibutyltindilaurate catalyst (0.2 pph) and component
E (0.6 pph).
Acrylic coating mixture-2 (silver):
[0083] The solution of acrylate polyol (component A; 56 weight %) as prepared above was
mixed with a 50 % by weight solution of aliphatic polyester diol (component B; 17
weight %) in toluene. Component D2 (8 pph) was added. The resulting mixture was rendered
homogeneous by mixing on a ball mill for eight hours at room temperature.
[0084] Directly preceding the coating in the Examples (see below), blocked isocyanate (component
C; 27 weight %) was added as well as dibutyltindilaurate catalyst (0.2 pph) and component
E (0.6 pph).
Acrylic coating mixture-3 (black):2a (silver)
[0085] The solution of acrylate polyol (component A; 57 weight %) as prepared above was
mixed with a 50 % by weight solution of aliphatic polyester diol (component B; 9.8
weight %) in toluene. Component D1 (8 weight %), component D2 (3 weight %) and 1 weight
% SP-green (Secure Products, NJ, USA) were added. The resulting mixture was rendered
homogeneous by mixing on a ball mill at room temperature for eight hours.
[0086] Directly preceding the coating in the Examples (see below), blocked isocyanate (component
C; 19 weight %) was added as well as tin(II) 2-ethylhexanoate catalyst (0.1 pph) and
component E (0.1 pph).
Acrylic coating mixture-3 (black)
[0087] The solution of acrylate polyol (component A; 56 weight %) as prepared above was
mixed with a 50 % by weight solution of aliphatic polyester diol (component B; 17
weight %) in toluene. Component D3 (7.5 pph) was added. The resulting mixture was
rendered homogeneous by mixing on a ball mill for eight hours at room temperature.
[0088] Directly preceding the coating in the Examples (see below), blocked isocyanate (component
C; 27 weight %) was added as well as dibutyltindilaurate catalyst (0.2 pph) and component
E (0.6 pph).
Acrylic coating mixture-4 (clear):
[0089] The solution of acrylate polyol (component A; 59 weight %) as prepared above was
mixed with a 50 % by weight solution of aliphatic polyester diol (component B; 15
weight %) in toluene. Glass beads were added (5 weight %). The resulting mixture was
rendered homogeneous by mixing on a ball mill for eight hours at room temperature.
[0090] Directly preceding the coating in the Examples (see below), blocked isocyanate (component
C; 26 weight %) was added as well as dibutyltindilaurate catalyst (0.2pph) and component
E (0.6 pph).
Acrylic coating mixture-4a (clear)
[0091] The solution of acrylate polyol (component A; 59 weight %) as prepared above was
mixed with a 50 % by weight solution of aliphatic polyester diol (component B; 9 weight
%) in toluene. 0.5 weight % of SP green was then added. The resulting mixture was
rendered homogeneous by mixing on a ball mill for eight hours at room temperature.
[0092] Directly preceding the coating in the Examples (see below), blocked isocyanate (component
C; 19 weight %) was added as well as tin(II) 2-ethylhexanoate catalyst (0.1 pph) and
component E (0.1 pph).
Acrylic coating mixture-4b (clear)
[0093] The solution of acrylate polyol (component A; 59 weight %) as prepared above was
mixed with a 50 % by weight solution of aliphatic polyester diol (component B; 9 weight
%) in toluene. 0.1 weight % of SP green and 0.5 weight % of Lumilux® C- Red CD 168
(Honeywell Europe, Seelze Germany) were then added. The resulting mixture was rendered
homogeneous by mixing on a ball mixer at room temperature for eight hours.
[0094] Directly preceding the coating in the Examples (see below), blocked isocyanate (component
C; 19 weight %) was added as well as tin(II) 2-ethlyhexanoate (0.1 pph) and component
E (0.1 pph).
Glass beads:
Glass beads having an average diameter of about 50µm and a refractive index of 2.3
Adhesive:
3M Transfer Tape 9458: acrylic pressure sensitive adhesive, having a thickness of
25.4 µm
Examples
Preparation of films or labels
Preparation of release carrier 6
[0095] A casting release carrier comprising a polymer-coated paper was prepared by taking
a 108 g HIFI Kraft paper (available from Chem Tenero AG) and coating it with a solution
of acrylic release material. The paper was then dried to give a dry coating weight
of 30 g/cm
2. The surface was smooth and glossy and exhibited an average roughness R
Z of approximately 1,0 µm. This release carrier is denoted below as release carrier
6/sample 1.
[0096] For screen printed films, a double side siliconized PET-release liner having a thickness
of 76µm and quality 1876, commercially available from Huhtamaki, was used. This release
carrier is denoted below as release carrier 6/sample 2.
Example 1
[0097] In a first step acrylic coating mixture-1 was printed as an emblem layer onto release
carrier 6/sample 1 using rotogravure method. The emblem layer was dried at 180 °C
for 1 minute.
[0098] Then acrylic coating mixture-2 was coated as polymer layer 3 onto the release carrier
6/sample 1 and oven dried at 180 °C during 2 min. Dry polymer layer 3, having a smooth
surface, was about 10 µm in thickness.
[0099] A polymer layer 8 comprising acrylic coating mixture-3 was coated onto the first
layer and dried at 200 °C during 2 min. The coating thickness of this second layer
was about 50 µm after drying.
[0100] In a next step, 3M Transfer Tape 9458 was laminated onto the polymer layer 8 to provide
pressure-sensitive adhesive layer 7 and the release liner 9. The coating thickness
of the adhesive layer 7 was 25.4 µm. Finally, the release carrier 6/sample 1 used
in the first step of the production was removed.
Example 2
[0101] In Example 2, a multilayer film was produced essentially according to the method
as described in Example 1, except that the emblem layer 4 was printed onto the release
carrier 6/sample 1 through screen printing. The emblem layer 4 was screen-printed
with the 3M™ Process Colour 8891 (red) and oven dried at 80 °C during 3 min.
[0102] A high cohesive bond between the emblem layer 4 and the polymer layer 3 was observed
by a cross-cut test with the 3M Scotch Tape 610, according to the test method EN ISO
2409.
Example 3
[0103] In Example 3, a multilayer film from which labels 1 can be cut was produced using
screen printing method.
[0104] In a first step, an emblem layer was printed onto Huhtamaki's release liner (release
carrier 6/sample 2) using 3M™ Process Colour 8891 (red). The emblem layer was dried
at 80 °C for 3 minutes.
[0105] In a second step, the polymer layer 3 was screen printed onto the pre-printed release
carrier 6/sample 2 using 3M™ Process Colour 844I (yellow) and oven dried at 80 °C
during 5 min. The dried polymer layer 3 was about 15 µm in thickness.
[0106] In a third step, a polymer layer 8 was screen printed onto the polymer layer 3 using
3M™ Process Colour 8851 (black) and dried at 80 °C during 10 min. The coating thickness
of this additional polymer layer 8 was about 50 µm after drying.
[0107] In a next step, 3M Transfer Tape 9458 was laminated onto polymer layer 8 to provide
adhesive layer 7 and release liner 9. The coating thickness of the adhesive layer
7 was 25.4 µm. Finally, release carrier 6/sample 2 used in the first step of the production
was removed.
Example 4
[0108] In Example 4, a multilayer film from which labels 1 can be cut was made with a retro-reflective
emblem layer 4, using a screen-printing method.
[0109] In a first step acrylic coating mixture-4 was screen-printed onto release carrier
6/sample 2 in a pattern or a logo to provide the emblem layer 4, which was then dried
at 180 °C for 1 minute.
[0110] Then acrylic coating mixture-2 was coated as polymer layer 3 onto the pre-printed
release carrier 6/sample 2 bearing the emblem layer 4, and was oven dried at 160 °C
during 2 min. The dry polymer layer 3 was about 15 µm in thickness.
[0111] A layer 8 was coated onto polymer layer 3, using acrylic coating mixture-3. The coating
was dried at 200 °C during 2 min. The coating thickness of this additional layer 8
was about 50 µm after drying.
[0112] In a next step, 3M Transfer Tape 9458 was laminated onto the additional layer 8 to
provide adhesive layer 7 and release liner 9. The coating thickness of the adhesive
layer 7 was 25.4 µm. Finally, the release carrier 6/sample 2 used in the first step
of the production was removed.
Example 5
[0113] In Example 5, a multilayer film from which labels 1 can be cut was made.
[0114] In a first step a modified acrylic coating mixture-1 comprising, instead of silane
modified titanium dioxide (component D1), 5 wt.% of glass based (average size of 40-60
µm) was printed onto release carrier 6/sample 1 in a pattern or a logo using rotogravure
method to provide the emblem layer 4 which was then dried at 180 °C for 1 minute.
The composition of acrylic coating mixture-1 was otherwise as indicated above.
[0115] In a second step acrylic coating mixture-4 was coated onto the pre-printed release
carrier 6/sample 1, bearing the emblem layer 4, to form polymer layer 3. Layer 3 was
oven dried at 180 °C during 2 min. The dried polymer layer 3 was about 15 µm in thickness.
[0116] A polymer layer 8 comprising an acrylic coating mixture as disclosed in Example 1
above was coated onto polymer layer 3 and oven dried at 180 °C during 2 min. The dried
additional polymer layer 8 was about 15 µm in thickness.
[0117] A further additional polymer layer 8a was coated onto the first additional polymer
layer 8 using acrylic coating mixture-3. The coating was dried at 200 °C for 2 min.
The coating thickness of this further additional polymer layer 8a was about 50 µm
after drying.
[0118] In a next step, 3M Transfer Tape 9458 was laminated onto the further additional polymer
layer 8a to provide adhesive layer 7 and release liner 9. The coating thickness of
the adhesive layer 7 was 25.4 µm. Finally, the release carrier 6/sample 1 used in
the first step of the production was removed.
Example 6
[0119] In Example 6, a multilayer film from which labels 1 can be cut is made which comprises
a clear retro-reflective additional polymer layer 8 next to polymer layer 3. This
construction offers the advantage that in case polymer layer 3 is laser-marked this
retro-reflective layer will be seen as a retro-reflective background by lighting.
[0120] In a first step emblem layer 4 was made by printing acrylic coating mixture-1 in
a pattern or a logo onto release carrier 6/sample 1 using rotogravure method. The
printed emblem layer 4 was dried at 180 °C for 2 minutes.
[0121] Then acrylic coating mixture-2 was coated onto the pre-printed release carrier 6/sample
1 bearing emblem layer 4, to make polymer layer 3 which was oven dried at 180 °C during
2 min. The dried polymer layer 3 was about 15 µm in thickness.
[0122] In a next step an additional polymer layer 8 was obtained by coating acrylic coating
mixture-4 onto the polymer layer 3. The additional polymer layer 8 was oven dried
at 180 °C during 2 min. The dried polymer layer 8 was about 15 µm in thickness.
[0123] A further additional polymer layer 8a was coated onto the first additional polymer
layer 8 using acrylic coating mixture-3. The coating was dried at 200 °C for 2 min.
The coating thickness of this further additional polymer layer 8a was about 50 µm
after drying.
[0124] In a next step, 3M Transfer Tape 9458 was laminated onto the further additional polymer
layer 8a to provide adhesive layer 7 and release liner 9. The coating thickness of
the adhesive layer 7 was 25.4 µm. Finally, the release carrier/sample 1 used in the
first step of the production was removed.
Example 7
[0125] In Example 7, a multilayer film was produced essentially according to the method
as described in Example 1, except that a micro-script with a height between 100 -
500 µm was printed in addition to the logo to form the emblem layer 4. This adds an
added security feature to prove the authenticity of the film. This micro script is
legible clearly by use of a magnifying glass.
Example 8
[0126] In Example 8, a single layer film was produced.
In a first step acrylic coating mixture-2a was printed as an emblem layer onto release
carrier 6/sample 1 using rotogravure method. The emblem layer was dried at 180 °C
for 1 minute.
Then acrylic coating mixture-2 was coated as polymer layer 3 onto the release carrier
6/sample 1 and oven dried at 180 °C during 2 min. Dry polymer layer 3, having a smooth
surface, was about 53 µm in thickness.
[0127] In a next step, 3M Transfer Tape 9458 was laminated onto the polymer layer 8 to provide
pressure-sensitive adhesive layer 7 and the release liner 9. The coating thickness
of the adhesive layer 7 was 25.4 µm. Finally, the release carrier 6/sample 1 used
in the first step of the production was removed.
Example 9
[0128] In Example 9, a single layer film was produced.
In a first step acrylic coating mixture-4a was printed as an emblem layer onto release
carrier 6/sample 1 using rotogravure method. The emblem layer was dried at 180 °C
for 1 minute.
[0129] Then acrylic coating mixture-2 was coated as polymer layer 3 onto the release carrier
6/sample 1 and oven dried at 180 °C during 2 min. Dry polymer layer 3, having a smooth
surface, was about 53 µm in thickness.
[0130] In a next step, 3M Transfer Tape 9458 was laminated onto the polymer layer 8 to provide
pressure-sensitive adhesive layer 7 and the release liner 9. The coating thickness
of the adhesive layer 7 was 25.4 µm. Finally, the release carrier 6/sample 1 used
in the first step of the production was removed.
Example 10
[0131] In Example 10, a single layer film was produced.
In a first step acrylic coating mixture-4b was printed as an emblem layer onto release
carrier 6/sample 1 using rotogravure method. The emblem layer was dried at 180 °C
for 1 minute.
[0132] Then acrylic coating mixture-2 was coated as polymer layer 3 onto the release carrier
6/sample 1 and oven dried at 180 °C during 2 min. Dry polymer layer 3, having a smooth
surface, was about 52 µm in thickness.
[0133] In a next step, 3M Transfer Tape 9458 was laminated onto the polymer layer 8 to provide
pressure-sensitive adhesive layer 7 and the release liner 9. The coating thickness
of the adhesive layer 7 was 25.4 µm. Finally, the release carrier 6/sample 1 used
in the first step of the production was removed.
Test methods
[0134] The labels obtained from the films by cutting were tested according to the following
test methods.
[0135] The results are given in Tables 1 - 3.
Abrasion resistance
[0136] The abrasion resistance was tested according to the CSA-test method C22.2 No. 0.15-M95,
using a Teledyne Taber Abrasion Tester, CS-10 Abrasion wheel, 250 gr. weight. The
test was run on 40 x 40 mm test samples (100 cycles).
[0137] The results of abrasion resistance as given in Table 1 are determined by visual inspection
of the abraded surface (after the 100th cycle) using following standard:
+ = good
++ = very good (no change)
Chemical and water resistance
[0138] The resistance to chemicals or water was tested by immersing the sample into the
respective test liquid for a period of 10 seconds, following by drying for 20 seconds.
This procedure was repeated five times. Test liquids used were n-heptane, n-iso-propanol,
diesel, drinking water.
The legibility of logo was determined by visual inspection using following standard:
+ = logo good legible
++ = logo very good legible (no change)
[0139] The results are recorded in Table 1.
Heat resistance
[0140] 100 mm x 25 mm samples, adhered to an aluminium plate were exposed to a temperature
of 120 °C and 180 °C for a period of one hour in a forced air oven. Each sample was
visually evaluated with respect to shrinkage, adhesion and colour changes.
[0141] The evaluation symbols given in Table 1 have the following meaning:
+ = good
++ = very good (no change)
Smear resistance - Rub test
[0142] The smear resistance of the printed logo, adhesion strength at the edges as well
as the adhesive oozing were tested according to the test method DIN 57700 (or VDE
700) and using several test liquids like water, n-heptane, iso-propanol and diesel.
[0143] The samples were adhered to an aluminium plate. The samples were rubbed during 15
seconds using a square of white tissue, soaked with water. This procedure was repeated
with each of the test liquids. For all samples a rating ++ was obtained, indicating
no visible change was detected.
Cross-cut test
[0144] The bonding of the logo to the top layer was tested accordingly to EN ISO 2409, using
3M Scotch Tape 610. All examples showed a very good bond between logo and top layer.
0 % of printed logo was removed during the test.
Reflection measurement
[0145] The reflection R' was measured according to DIN 67520-2, using an illumination angle
of +5° and an observation angle of 0.33°. The results, recorded in cd/(m
2.lux) are given in Table 2.
Tensile strength and elongation
[0146] The tensile strength and elongation of the labels was measured according to AFERA
4004 and AFERA 4005 test methods respectively. The tests were done on specimen of
1 inch width. Testing conditions were 22 °C and 50 % relative humidity.
The tensile strength at break (N/cm
2)and the elongation (%) are recorded in Table 2.
Roughness measurement Rz
[0147] The roughness of the polymer layer 3 was measured according to Test Method DIN EN
ISO 1302 (06/02) using a Perthometer M2 testing equipment, available from Mahr. The
results, recorded in µm are given in Table 2.
Table 1 : Performance result
|
Thickness (µm) of label (without adhesive) |
Resistance rating |
|
|
|
|
Heat at |
Ex.-No. |
Abrasion |
Chemical/water |
Smudge |
120 + 80°C /1hr |
180 + 120°C/1hr |
1 |
63 |
++ |
++ |
++ |
++ |
++ |
2 |
66 |
+ |
++ |
++ |
++ |
++ |
3 |
65 |
+ |
++ |
++ |
++ |
++ |
4 |
63 |
+ |
++ |
++ |
++ |
++ |
5 |
65 |
++ |
++ |
++ |
++ |
++ |
6 |
62 |
++ |
++ |
++ |
++ |
++ |
7 |
65 |
++ |
++ |
++ |
++ |
++ |
8 |
53 |
+ |
++ |
++ |
++ |
++ |
9 |
53 |
+ |
++ |
++ |
++ |
++ |
10 |
52 |
+ |
++ |
++ |
++ |
++ |
Table 2: Performance
Ex.-No. |
Tensile Strength at break (N/cm2) |
Elongation (%) |
Reflection R' [cd/(m2.lux)] |
Roughness Rz (µm) |
1 |
4157 |
5,21 |
0,0 |
1,32 |
2 |
3481 |
5,6 |
0,0 |
1,47 |
3 |
2252 |
11,0 |
0,0 |
1,39 |
4 |
3730 |
4,9 |
0,1 |
1,80 |
5 |
3458 |
5,89 |
0,44 |
1,87 |
6 |
3410 |
5,87 |
0,0 |
1,63 |
7 |
3306 |
6,1 |
0,0 |
1,71 |
|
|
|
|
|
|
|
|
|
|
8 |
2055 |
6,2 |
0,0 |
1,35 |
9 |
2115 |
5,1 |
0,0 |
1,41 |
10 |
2032 |
4,8 |
0,0 |
1,33 |
Table 3:
The pigment detection was carried out after performing the tests listed below. A 3M
Laser Reveal Verifier commercially available from 3M Deutschland GmbH, Germany was
used for examples 8 to 10. In example 10 also a Money Detector from Conrad GmbH, Germany
was used. In all examples, the pigments were clearly detected. Additionally, the sample
of example 10 was inspected visually after oven aging at 120°C for 1 h. No migration
of the pigments to the reverse side the label/emblem construction was observed. |
|
Resistance rating |
|
|
|
After immersion test in water, n-heptan, iso-propanol, diesel |
Heat at |
Ex.-No. |
Taber Abrasion |
After smudging test with water, n-heptan, iso-propanol, diesel, MEK |
80°C / 1hr |
120°C / 1 hr |
8 |
O |
++ |
++ |
++ |
++ |
9 |
+ |
++ |
++ |
++ |
++ |
10 |
+ |
++ |
++ |
++ |
++ |
List of reference numbers
[0148]
- 1
- Label
- 2
- precursor of label 1
- 3
- polymer layer
- 3a
- major surface of polymer layer 3 facing release surface 6a
- 3b
- major surface of polymer layer 3 opposite to major surface 3a
- 4
- emblem layer
- 5
- emblem(s)
- 6
- release carrier
- 6a
- release surface
- 7
- adhesive layer
- 8
- further polymer layer
- 9
- release liner
- 10
- protective layer