Note: Descriptions are shown in the official language in which they were submitted.
1 ~7530~
Metallised labels
The present invention relates to metallised labels
for containers such as bottles.
It is known that in the labelling industry there is a
requirement for labels having a metallic appearance. It is
obvious to use for this purpose a metallic foil. However,
with respect to returnable bottles, such labels cannot be
removed by using standard techni~ues, involving immersion in
a bath of 1.5 weight % of caustic soda, having a temperature
of ~0C, within a period of 3 minutes. Further in such a
bath metallic foil labels react with caustic soda, due to
which its strength is reduced such that the caustic soda
has to be changed frequently.
For said reasons, it would be advantageous to use
metallised papers for this purpose, since such papers have a
low metal content in comparison with a metallic foil.
Metallised papers are generally known. A very useful type is
disclosed in Dutch Patent application 8,000,967 (in the
name of the assignee of the present application and published
September 16, 1981) as with a foil label the requirements are
~0 the same of which the chief are appearance and ease of removal
in the above caustic soda solution. Lacquersj preferably
acrylic resin based lacquers, are used to provide protection
for the metallic layer against water and oxygen and also to
enable the product to perform satisfactorily on labelling
machines.
In order to enable a metallised label to be
satisfactorily removed from a bottle, it is necessary that the
hot caustic soda solution can attack the adhesive layer between
~bottle and paper. For this to occur within a relatively short
time, the caustic soda has to rapidly reach the paper layer.
That is to say it must rapidly pass through the lacquer and
metallised layer. The latter problem is obvlated with this
invention in that a very thin layer of metal which has been
vacuum deposited in the label construction will provide a
low resistance to the hot dilute caustic soda solution.
There are two potential ways of achieving the
desired penetration of the lacquer.
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solubility of lacquer
- thickness of lacquer
The commercially available lacquers which are readily dissolved
by dilute alkali are ideally suited for applications involving direc-t
metallising where the lacquer is applied after metallising. ~lowever,
the resultant products from direc-t metallising have an inferior mirror
reflec-tivity as compared with indireet metallised papers.
Such lac~uers, whieh are used for diree-t metallised labels are not
suitable in the indireet process where the lacquer is applied before
metallising because the lacquer must have low volatiles at reduced
pressures.
Laequers soluble in dilute alkali and having low volatiles under
redueed pressure are not eommereially available.
It would be possible to employ a thin laequer layer thereby
allowing the eaustie soda to reaeh the metallised layer by a permeation
mechanism. This has appeared to be unsatisfaetory. If the laequer
thiekness is less than about 1.7 um, interferenee fringes may oeeur
whieh detraet from the end produet's appearanee.
It was found now, that metallised labels, glued to bottles by
means o~ a glue that is not resistant against an aqueous eaustic soda -
solution, containing 1.5 % by weight of caustic soda, at a temperature
of 80 C, may be removed within a period of 3 minutes from said bottles,
by using labels coated with a laequer wherein 2 to 10 weight % hot
; dilute alkali soluble additives that do not attaek the metal Iayer of
said label have been ineorporated. When said additives have been
dissoIved ln said allcaline solution, thé laequer eoating starts -to
eraek or to split and to swell. Subsequently the underlying metallic
layè~r~ls;dissolved`and -Finally the paper subs-trate and glue (easein
based) are attacked. Sueh additives may be dissolvecl and subsequently
dispersed or directly ground into -the lacquer. The preferred laequers
and -techniques of manufacture are those used in DPA 80.00967.
Preferably said additives are distribu-ted in said lacquer a-t a
particle size of up to 2 um.
Further it is preferrecl-that said additives are Food and Drug
Act (F.D.A.) approved.
Evidently it is preferred that said adclitives do not react with
caustic soda and have a low vapor prcssure.
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In many cases it is preferred that said additives are colourless
or clear.
Preferred additives are sugar-like materials such as sucrose,
mannitol and urea. Also water based resins 9 including acrylic emulsions,
polyvinylalcohols and polyacrylamides, substituted celluloses, such as
nitrocellulose, carboxyethyl and carboxymethyl cellulosesand urea-
formaldehyde types (e.g. melamine) may similarly be included.
Further it is preferred that a paper is used which has been
subJected to steam or conditioned at high humidity immediately prior
to the laminating step described in DPA 60.00967. The resultant label
has been found to give beneficial results with respect~-to processing
at the printing and label application stages and with respect to ease
of label removal from the container.
The mirror reflectivity of a sample surface can be measured by
adherring a 150 mm x 200 mm sample to a smooth flat glass surface. At
an angle of 60 to the sample is placed a 150 mm x 250 mm grid on which
is marked 10 mm squares and numerals 1-25 in the vertical direction.
The sample surface is illuminated by standard photographic lamps
A 5" x 4l1 Micro Precision Products Technical Camara with a Schneider
Xenar 1:4.5/150 lens and aperture F16 is situated 500 mm from the
point of contact of grid and sample~at an angle of 30 to sample-. The
focus is on the reflected numeral 1 from the grid and a photograph is
taken. The mirror reflectivity of the sample surface is determined by
examination of the photograph to see the highest number at which a
clear reflected image is obtained. This number gives the mirror
reflectivity rating of the sample surface.
Example 1
A lacquer solution was prepared by dis~olving 100 parts by weight
of Bakelite*Vinyl Solution Resin VMCH in 300 parts by weight of
butanone-2. The resultant lacquer solution was applied to the ca~rier
film at a dry coating weight of 2.2 grams per square meter (gsm) using
a drying temperature of 7~C.
A coherent continuous stratum of aluminium metal was then vapour
deposited by standard methods upon this lacquer layer.
A layer of solvent based laminating adhesive Adcote ~40 was
applied to the metal layer at a dry coating weight of 2.~ gsm to bond
the carrier (Hescolina Base paper (60 gsm)) to the composite.
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After 7 days the carrier film was stripped from the composite
structure to produce a laminar product which had a reflectivity rating
of 5, according to the method described in the text.
From the resultant laminar product was cut a 100 mmx 100 mm
label which was bonded to a glass bottle using a standard casein glue
(ex Houstr~). After 7 days storage at ambient conditions the bottle
plus label was immersed in a 1.5 % aqueous caustic soda solution at
80C
The label failed to release after 25 minutes.
Example 2
3.0 parts by weight of sucrose were dissolved in~-9 parts of
water and this solution was mixed into a lacquer solution comprising
100 parts by weight of Bakelite Vinyl Solution Resin VMCH, 300 parts
by weight of butanone-2, The resultant lacquer solution was applied
to a polypropylene carrier film at a dry coating weight of 2.4 gsm
using a drying temperature of 70C.
A coherent continuous stratum of aluminium metal was then vapour
deposited by standard methods upon this lacquer layer.
7.5 parts by weight of sucrose were dissolved in 22.5 parts of
water and this was mixed into a laminating adhesive solution
comprising 100 parts of- Adcote 340, 115 parts by weight of methanol
and 15 parts of catalyst. The resultant laminating adhesive solution
was applied to the metal layer at a dry coating weight of 30 gsm to
bond the Hescolina Base Paper (60 gsm) to the composite.
After 7 days the carrier film was stripped from the composite
structure to produce a laminar product which had a mirror reflectivity
rating of 4~ determined according to the method described in the
text.
From the resultant laminar product was cut a 100 mm x 100 mm
label which was bonded to a glass bottle using a standard casein glue
(ex Houstra). After 7 days storage at ambient conditions the bottle
- plus label was immersed in a 1.5 ~ aqueous caustic soda solution at
80C
The label released from the bottle after 7 minutesO
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A lacquer solution was prepared by dissolving 70 parts by weight
of Neocryl*~811 (ex Polyvinyl Chemie) and 30 parts by weight of Vinnol*
H40/55 (ex Wacker) in 210 parts by weight of butanone-2 and 90 parts
by weight of ethyl acetate.
The resultant lacquer was applied to the polyester carrier film
at a dry coating weight of 2.5 gsm using a drying temperature of 70C.
A coherent continuous stratum of aluminium metal was then vapour
deposited by standard methods upon this lacquer surface.
A layer of an aqueous based styrene butadiene emulsion adhesive
was applied to the metal layer at a dry coating weight of 4 gsm to
bond the substrate (Hescolina*base paper (60 gsm)) to the composite.
After 7 days the carrier film was stripped from the composite
structure to produce a laminar product with a mirror reflectivity of
5. From the resultant laminar product was cut a lOO,mm x 100 mm label
which was bonded to a glass bottle using a standard casein glue.
After 7 days storage at ambient conditions, the bottle plus
label was immersed in a 1.5 % caustic soda solution at 80C.
The label released from the bottle after 14 minutes.
ExampIe 4
As example 3 but 3 parts by weight of sucrose dissolved in
9 parts by weight of water were added to the lacquer.
Mirror reflectivity rating of 4.
~ The label removal time was 3.5 minutes.
Example 5
As example 3 but 3 parts by weight of sucrose were ground into
the lacquer.
Mirror reflectivity rating of 5.
The label removal time was 158 seconds.
Example 6
As example 3 but 5 parts by weight of dextrose monohydrate
were ground into the lacquerO
Mirror reflectivity rating of 4.
-The label removal time was 130 seconds.
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Example 7
As example 3 but 7 parts by weight o-f sucrose were ground into
thc lacquer.
I~lirror reflectivity rating of 4.
The label removal time was 220 seconds.
Example 8
A lacquer solution was prepared by dissolving 75 parts by weight
of lleocryl B 811 and 25 parts by weight of Vinnol H 40/55 in 210
parts by weight o-f butanone-2 and 90 parts by weight o-f ethyl acetate.
To this solution were added 3 parts by weight of sucrose dissolved in
9 parts by weight of water. The resultant lacquer solut-ion was applied
to the polyester carrier film at a dry coa-ting weight of 2.6 gsm
using a drying temperature of 70C.
Then as example 3.
Mirror reflectivity 4.
The label released from the bottle after lOS seconds.
Example 9
As example 8 but 5 parts by weight of sucrose were ground
into the lacquer.
Mirror reflectivity 4. ---
The label released from the bottle after 95 seconds.
Example 10
A lacquer solution was prepared by dissolving 80 parts by weight
of~ileocryl B 811 and 20 parts by weight of Vinnol H 40/SS in 210
parts by weight of butanone-2 and 90 parts by weight of ethyl ace-tate.
To this solution were added 5 parts by weight of sucrose dissolved
in~15 parts by weight o~ water. The resultan-t lacquer solution ~vas
applied to the polyester carrier film at a dry coating weight of 2.6
gsm~using a~drying temperature of 70C.
30~ Then as example 3.
llirror reflectivity 4.
The label released from the bottle after 115 seconds.
Example: 11
As example 10 but 5 parts by weight of sucrose were ground into
thc lacquer.
llirror re-Flectivity 5.
The label removal time was 9G seconds.
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Example 12
A lacquer solution was prepared by dissolving 80 parts by weight
of Neocryl B 811 and 20 parts by weight of Vinnol H 40/55 in 210 parts
by weight of butanone-2 and 90 parts by weight of ethyl acetate. To
this solution was added 10 parts by weight of Neocryl BT21 (ex Poly-
vinyl Chemie) which is an emulsion in water. The resultant lacquer
solution was applied to a polyester carrier film at a dry coating
weight of 1.7 gsm using a drying temperature of ROC,
A coherent continuous stratum of aluminum metal was then vapour
deposited by standard methods upon this lacquer surface.
A layer of an aqueous based styrene butadiene adhesive was
applied to the metal layer at a dry coating weight of 4 gsm to bond
the substrate (Hescolina base paper 60 gsm which had been subJected
to steam at 20 psi for 10 seconds) to the composite.
After 7 days the carrier film was stripped from the composite
structure to produce a laminar product.
Th~n as example 3.
Mirror reflectivity 4.
The label removal time was 150 seconds.
Example 13
A lacquer solution was prepared by dissolving 80 parts by weight
of Neocryl B 811 and 20 parts by weight of VinnoI H 40/55 in 210 parts
by weight of butanone-2 and 90 parts by weight of ethyl acetate. To
this solution was added 5 parts by weight of polyvinylàlcohol Poval *
105 ex Kuraray* dissolved in 25 parts of water.
The resultant lacquer solution was applied to a polyester
carrier film at a dry coating weight of 1.7 gsm using a drying
temperature of 80C.
A coherent continuous stratum of aluminum metal was then
vapour deposited by standard methods upon this lacquer surface.
A layer of an aqueous based styrene butadiene adhesive was
applied to the metaI layer at a dry coating weight of 4 gsm to bond
the substrate (~lescoline base paper 60 gsm which had been subJected
to steam at 20 psi for 10 seconds) to the composite.
After 7 days the carrier film was stripped from the composite
structure to produce a laminar product.
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Then as example 3.
The resultant laminar product had a mirror reflectivity of 5
and the label released from the bottle after 160 seconds.
Example 14
A lacquer solution was prepared by dissolving 80 parts by weight
of Neocryl B 811 and ~0 parts by weight of Vinnol H 40/55 in 210 parts
by weight-of butanone-2 and 90 par-ts by weight of ethyl acetate. To
this solution was added 10 parts by weight of Neocryl BT21 ~ex
Polyvinyl Chemie) which is an emulsion in water.
The resultant lacquer solution was applied to a polyester
carrier film at a dry coating weight of 1.7 gsm using ~ drying
temperature of 80C.
A coherent con-tinuous stratum of aluminum metal was then vapour
deposited by standard me-thods upon this la_quer surface.
A layer of an aqueous based styrene butadiene adhesive was
applied to the metal layer at a dry coa-ting weight of 4 gsm to bond
the substrate (Hescolina base paper 60 gsm, that had not been
subJected to a steam treatment) to the composite.
After 7 days the carrier film was stripped from the composite
structure to produce a laminar product~
The as example 3.
The product had a reflectivity of 6 and the label released
from the bottle after 160 seconds.
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