Note: Descriptions are shown in the official language in which they were submitted.
341Z
b~:~iVe_L~ b~ ç~ ;hgl;eQf~
This invention relates to self adhesive labels and the
manufacture thereof, and in particular concerns labels
which are supplied in roll form. The labels will
mainly be for application, using suitable machinery, to
05 individual articles or objects and to tnis end the
invention also provides a method of and means for
applying labels to articles or objects, or the labels
may simply be for detachment individually by hand as is
the case when labels are provided, for example, for
office use.
It is in fact in the field of produce marketing that
pressure sensitive labels find widest application
because, for example, in supermarkets and other stores
the products on sale are typically priced by means of a
small pressure sensitive label which is applied to the
product, and frequently these labels have to be changed
because of price change, making consumption of the
labels enormous.
Also, huge quantities of labels which are applied to
containers such as bottles and cans are used, and
indeed there are many areas of application for pressure
sensitive labels.
Typically, pressure sensitive labels are mounted on a
carrier or backing web which is normally a web of paper
coated with a suitabale release material such as a
silicone compound. The adhesive labels are applied to
this carrier or backing web for transportion, storage
and utilisation, but the labels can readily be peeled
from the ~acking web as there is much a stronger bond
between the adhesive and the material of the label,
than between the adhesive and the release material.
~2484~.2
Not only is the backing web superfluous after the
labels have been peeled therefroM and consumed, but the
manufacture of the backing web is a specialist process,
and must be performed under carefully controlled
05 conditions The equipment to produce the backing web
is expensive, and is extremely large, so that only a
very few companies are able to finance and perform the
backing strip manufacture. This arises due to the fact
that the release material when applied to the backing
paper is largely absorbed by the paper (beiny a
fibrous, absorbent material), and considerable
quantities must be applied and in carefully controlled
conditions in order to achieve an outer surface layer
of the release coat material which will perform the
required function. The relase coat material is a
polyerisable material ana requires to be heated af~er
application to the paper. The heating time, in order
to polymerise the material is related to the quantity
applied, and because of the absorbency of the paper web
a long period of heating is required to produce the
finished product.
There have been proposals to eliminate the backing
strip in adhesive labels, but such proposals have not
met with any commercial success. One of these
proposals as set forth in U.S. Patent No. 3,575,788
wherein a backless roll of labels is produced by
printing on clay coated paper on one side with a nitro
cellulose base ink, and by coveriny the ink with a heat
- cured thermo setting silicone resin release coating,
the othec side having a ~ressure sen~itive adhesive
applie~ thereto. The silicone release coating is cured
at a temperature of 3S0F to 500F.
At such temperatures, there would be a considerable
tendency cor the paper to wrinkle, and it is believed
tnat for this reason, this proposal has not reached
2~341~
commercialisation. In any case, the extra step of
applying the nitro cellulose ink increases the plant
size, time of production and cost of production. For
whatever reason other proposals for backless labels do
05 not appear to have been commercialised, because there
are no backless pressure sensitive labels on the
market.
The present invention is concerned with novel forms of
pressure sensitive labels, and with a method for
produciny pressure sensitive labels which adapts itself
to the utilization of relatively simple and relatively
small dimension machinery, enabling the in-house
production of pressure sen~itive labels by the
manufacturers of the basic substrate material. Such a
manufacturer typically is rererred to as a "convertor"
in that he converts the raw material into sheets and
webs. The invention also relates to machinery for
producing the labels and a method of and means for
applying of such labels to products.
According to a first aspect of the invention there is
provided ahesive labels in roll form defined by a web
of non-porous material which is substantially non-
etensible, said web having at one side of the web apressure sensitive adhesive and haviny at the other
side of the web a pressure sensitive adhesive release
coatiny whereby the web can be rolled up without the
need for a backing strip.
The use of a non-porous web presents the considerable
advantage that when the release coating is applied
thereto, it can be applied in relatively small amounts,
which means that the curing tinle for the release
coating is reduced, and lower curing temperatures (as
compared to the curing temperatures used in U.S. Patent
No. 3,575,788 can be used). Moreover, it is not
~2~8412
necessary to apply a nitrocellulose base ink to the web
before application of the release coating.
It is preferred that the web should be other than
05 cellulose fibre based as cellulose fibre webs have the
disadvantages as aforesaid.
The web is preferably of a relatively norl-extensible
material so as to enable the individual labels to be
cut therefrom.
The pressure sensitive adhesive may cover the entire
surface area or parts of the surface area which in
certain cases minimises the risk of the pressure
sensitive adhesive beiny squeezed from the coil of
laDels to interfere with the unwinding of the web and
can increase the ease with which the web of labels can
be applied to the product. Preferably, the web is die
cut to define individual labels therein and the release
2~ coating is applied over the cuts to provide extra
retention strength holding the labels together or to
the remainder of the web.
The perforations or other lines of weakening caused by
the die cuttinc~ may define the labels so that when the
labels are removed from the web there remains a
skeletal waste of the web material, but it is also
within the scope of the invention that the perforations
or other lines of weakening should be arranged so that
the entire web area defines labels, with no surplus.
The web may be printed to define the labels, the
printing beincj on the side of the web to which the
release coating is aplied. Preferably, the we~ is of a
synthetic resinous material containing an inorganic
filler such as talc or chalk.
5 ~ 12
According to another aspect of the invention there is
provided adhesive labels in roll form comprising a web
o~ base material, a pressure sensitive adhesive on one
side of the web and a pressure sensitive adhesive
05 release coating on the other side so that the web can
be rolled up without the use of a backing strip, the
web having defined therein, by die cutting or the like,
individual labels, which can be individually detached
from the roll, and by virtue of the adhesive, attached
to articles to be labelled.
In this aspect of the invention, the web may be fibrous
or non-Eibrous, the novel feature being that the web
has individual labels defined therein for removal
lS therefrom, each haviny pressure sensitive adhesive on
one side and release coating material on the other web.
Preferably, the release coatiny is applied to the web
after the die cutting or the like, so that the release
coatiny fills the cuts to lessen the tendency of the
labels to detach from the web as unrolling of the web
is taking place.
Also, according to the invention there is provided a
method of manufacturing labels wherein a web of non-
fibrous material which is relatively inextensible isprinted to define individual labels therein, a pressure
sensitive adhesive is applied to one side of the web
and a pressure sensitive adhesive release coating is
applied to the other side of the web so that the web of
labels can be rolled up without rec~uiring a backing
strip, the adhesive and release coating being
subjected, if necessary, to treatment to dry/and cure
the same before rolling the web into roll form.
Preferably also, the release coating is a heat curable
material, and the web is passed through a hot air oven
at a temperature o~ lloC to cure the release coating.
-
- ~2484~2
It is preferred that the web should travel in a
continuous path through a release coating station, a
release coatiny curing station, an adhesive application
station and an adhesive drying station, but not
05 neccessarily in that order.
According to yet a further aspect of the invention
there is provided a method of applying labels as
aforesaid to articles wherein the web is advanced to a
unit operating in synchronism with the feed of articles
to which the labels are to be applied, said unit taking
labels one by one from the web and applying same to the
moving articles.
The web material defining the labels will be of a
~hickness consistenl wi~h the Ihickness of the la~els
as conventionally used and may be provide~ with
sprocket feed holes at the edges thereof.
For the application of the labels which are defined in
the web and are removable from the web to leave a
skeletal waste, there may be an applicator arranged to
punch a portion of the label $rom the web to cause that
portion to adhere to the appropriate article, and the
article and web are relatively movable from this
position so that the relative movement causes the
remainder of the label to be removed from the web.
Where the said labels are defined by perforations,
these may be such as to leave sufficient "catchpoints"
between the label and the remainder of the web so that
the label will remain in position of the web until such
times as it is forceably rernoved or dis~laced
therefrom. l'he leading edge of the label, which i5
first attached to the product or article may befree oE
such catch points so that it will deflect readily out
of the web to sinlplify application.
~484~2
~ 7 -
1 The release coating may be applied to the web by rollers,
gravure cylinders or hot melt applicators to provide a
surface having a release characteristic. The coating may
for example contain non-migrant repellants, and in par-
ticular, polymerisable silicone polymers. The coating
may for example be a soluent heat cured coating, an aqueous
system, solvent free or UV cured, examples of the above are
as follows:
Solvent Heat Cured
A) Silcolease* (TM) 425 (30%~ (ICI) 100 parts by weight
Catalyst 62A (ICI~ 4 parts by weight
Catalyst 62B (ICI) 4 parts by weight
Toluene 200 parts by weight
Curing Time at 120C 10 seconds
100C 15 seconds
90C 20 seconds
Dry off solvent prior to cure approx. 5 seconds.
B) a) Syloff* 7046 Basic polymer dispersion.
b~ DowCorning* 7047 Curing agent for Q2-7046*.
al and b) are used in ratio
of 10:1 typically.
c) Q2-7090* (Dow Corning) Premium release
additive. Is used in
varying proportions
to lower release
levels of basic
Q2-7046*.
d) Q2-7089* (Dow Corning) Release modifying
*Trade Mark
r-
'1248412
d) Q2-7089 (Dow Corning) ~elease modifyiny
agent. Can be used
in varyirlg amounts to
~L~elevelof
release of Q2-7046
05 and yives stable
modified release
levels.
- i B e) Q2-7127 (Dow Corning) Accelerator for
Q2-7046. Is used in
minute quantities ~o
accelerate the cure
rate of Q2-7046.
Especially useful for
lowtemperature
curing on substrates
such as polyethylene
film.
20f) Syloff 297 (Dow Corning) Anchorage additive.
Necessary to provide
abrasion resistance
for off-line work
(except using P~K).
In the following proportions by volume.
30 Sylo~f 7046 i 1 2 lU ~ 5 r
Crosslinker 7047 2 2 1 2.2 3.2
Q2-7090 _ _ _ _ 2
Q2-70~9 _ _ _ 2
Q2-7127 _ _ 0.0~ _ 0.03
35 Sylof-L 297 _ 0.2 _ 0.2
Solvent 78 78 89 80 82
.- . .
Tr~
i2484~2
~}_Lb_l - Stanclard bath for in-line use or off-line on
certain substrates such as PEK.
~h_~ - Standard bath for off-line use, usin~ Syloff
,97 anchorage additive.
()S
~h_~ - Special low solids bath for coating films such
as ~olyethylene. Solvent choice important
and ethyl acetate best. Uses Q2-7127 as
accelerator.
~Sh_~l - Controlled release bath. Features Q2-7089 as
release modifier and Sylo~f 297 as
anchoraye additive.
15 I?,ath_5 - Premiulil release formulation involving
incorporation S22-7090 low viscosity
fluid ancl aoditional Q2-7127 to restore
catalyst level.
- 20 These are only typical baths and levels of accelerator,
release modifier and premium release additive can all
be varied to satisEy customer demand~.
~_~iD~a_cQ~ditio~
Bath 1 and 2 cure in 8-12 seconds at 140C depending on
substrate nature.
Bath 3 will cure in 15-20 seconds at 70C.
Bath 4 cures typically in 15 seconds at 140C.
Bath 5 cures in 30 seconds at 100C or 10 seconùs at
140C.
- ~24~34~2
.a~Q~S_~iY~ S
A~ SY L O F F 1 17 1 * (5 09~) (D o w C o r n i n g)
Organopolysiloxane 14 parts by weight.
05
C.M.C. (Carboxy methyl cellulose) 2
parts by weight.
B Catalyst 1171P~Dow Corning) Organo-tin
Acylate 1.4 parts by weight.
or Catalyst 164'7 (Dow Corniny) Organo-tin
Mercaptoacetate 3.5 parts by weight.
Water To yive 100 parts by
weight.
Cure time 10 seconds at 120C
20 ~iQlY~ g_~ Q~}$
A) Syloff 7044(10096) (Dow Corning) 100 parts by
weight.
Crosslinker 7048 (1009~) (Dow Corning) 4 parts by
weight.
B) Coating Q2-7069 (100~6) (Dow Corning) 100 parts by
weight.
Crosslinker 7048 (100~6) (Dow Corniny) 4 parts by
weight.
Cure time A) 40 seconds at 120C 10 seconds at
170C.
B) 30 seconds at 170C
~ ~e ~
~Z48*~2
SL~ ~ÇYL~
A) Silicone Dehasiv VP 1502 (100%) (Wacker) 100 parts
by weight.
05 Crosslinkiny Agent VP 1503 (100%) (Wacker) 4 parts
by weight.
Catalyst OL (100%) (Wacker) 0.4 parts
by weight.
; B lo B) Silicone X-62-7004 (100~) (Shin-Etsu Ghemical Co.
Ltd) 100 parts by weight.
Catalyst X-92-095 (100~) (Shin-Etsu Chemical Co.
Ltd) 10 parts by weiyht.
Cure rate 0.6 seconds with high pressure mercury
Vapour U. V. lamp (160 W/cm).
The amount of release coating applied may be in the
order of 0.1 to 1.5 grams/sq. metre depending upon the
web. The pressure sensitive adhesive may be applied by
conventional means, and typicallay may be a solvent or
water based emulsion of which the solvent or water is
dried from the web after application. ~he pressure
sensitive adhesive may for exaMple be hot melt, water
based, or solvent based, examples of which are as
follows:
~Q~_ gl~
309 Elvax *40-P (Du Pont) (Ethylene-vinyl acetate resin)
40 parts by weight.
Piccovar* L-60 (llercules Inc.) (Hydrocarbon resin)
60 parts by weiyht.
Irganox *1010 (Ciba Geigy) (Antioxidant) - 0.5 parts
by weight.
~ ~e ~ k
12 1248412
~g~Q~
Indatex SE2229S (Industrial Adhesives Ltd)
05
SQ1Y~
Vinalak 5150 (Vinyl Products Ltd)
The labels rnay be colour printed by any suitable method
such as letter press, flexographic, gravure or offset
litho.
~ or the web material, it is preferred to use
polypropylene or high density polyethylene film,
including substantiaï propor~ions o$ particulate
inorganic ~laterial.
Typically, the inorganic material may be included in
the range 20 to 50% of the web by volume, and in the
preferred case the web is polypropylene ethylene
sequential copolymer, as described in our British
Patent No. (1544,143) filled with 40~ talc.
Embodiments of the present invention will now be
described, by way of example, with reference to the
accompanying diagrammatic drawings, wherein:-
Fig. 1 is a perspective view of a roll of labels
according to the present invention;
Fig. 2 is an enlarged seçtional elevation of the webshown in Fig. l;
Fig. 3 illustrates diayrammatically one embodiment of
how the labels are applied to indivil~ual cans,
."
12
13
Fig. 4 shows the process of Fig. 3 in side elevation;
Fig. 5 shows a roll of labels according to a second
embodiment of the invention;
05
Fig. 6 shows in perspective view how a roll of labels
is utilised in accordance with another apsepct of the
invention;
Fig. 7 illustrates how the labels of Fig. 1 are applied
-- to box shaped products;
Fig. 8 illustrates apparatus for the coatiny of the web
of labels with pressure sensitive adhesive and release
coatin~ accordin-J to one metho~;
Fi~s. 9 and 10 illustrate apparatus for the said
coating accordiny to two other methods, and Fig. 11
illustrate~ apparatus which is a modification of the
Fig. 10 apparatus.
Referring firstly to Figs 1 to 6 of the drawings, in
Fig. 1 there is shown a web 10 having perforations 12
defininy individual labels 14, each provided with
printing 16. Catchpoints 18 serve to hold the labels
to the remainder of the web 10, but the catchpoints can
be burst or cut to enable removal of labels 14 leaving
a residual skeletal waste.
As shown in Fig. 2, the web 10 is made up of a central
substrate web 20 which is of a non-fibrous anu
substantially inextensible material and on one side of
which is applied a pressure sensitive a~hesive coating
22, and on the other siee is applied a release coating
24. The web is shown in ~reatly enlaryed ~imen6ion in
Fiy. 2, to illustrate the slits 12 and also to
illus~rate how the coatin~ materials 22 and 24 migrate
14 ~iL2484~12
into the said slits 12. The substratge 20, adhesive
coating 22 and release coating 24 are of a nature as
described herein, and the web is wound so that the
adhesive coating 22 is to the inner side of each coil
05 and contacts directly on the release coating 24 of the
adjacent inner coil. This arrangement enables the web
10 to be easily unrollecl. The web may be wound on a
suitable core 26.
10 In produciny the web 10 as illustrated in Fiy. 1, the
printing 16 (single or multi coloured and of any
clesire~l pattern alld/or content) is applied to the
subs~rate 20 prior to the appliation of the coating 24
anà in a~idition, the perforations or slits 12 are
15 ~orlned prior to the application of the said coatiny 24.
The coa~iny 24 in fact has the errect of assisting the
holdin3 of tne labels 14 in ~osition in the web until
~hey are removed for application to articles. The
coating 24 also serves the purpose of preventing
20 migration of the adhesive 22 though the slits 12 when
the web is wound on core 26. This tendency to mi~rate
will depend upon how tightly the roll is wound on core
26.
25 Figs. 3 and 4b illustrate diagramlllatically how the
individual labels 14 may be renloved from the web 10 and
applied to can bodies such as can body 28. In fig. 3,
the web 10 is shown as travelliny round a yuide drum 30
in the direction of arrow 32, with the pressure
30 sensitive adhesive coatiny side outermost. Each can 28
to be labelled comes into contact with the pressure
sensitive side of the web 10, and a label 14 is removed
from the web 10 and applied to the can body 28, as
shown in Fig. 4. How this is achieved will depend upon
35 the design of the equipment, but it is envisaged tha
the web 10 will be held by suitable sprocket wheels or
rollers enya~ing holes at each side of the web and the
-
124~12
web will be illdexea forwards towards the product to be
labelled. ~he leading edge of the label, having regard
to its direction of movement (arrows 32), can be
released fronl the web by a suitable knife or by virtue
05 of changing the direction of movement of the web
sharply. The contact pressure between the pressure
sensitive surface and the product being labelled can be
used to effect or a~sist the complete removal of the
label from the web. The removal may if necessary be
assisted by severing the remaining catchpoints 18 by
means of suitable knives positioned appropriately. The
skeletal waste of the web 10 may be wound up into a
suitable coil for disposal.
The web shown in Fig. 1 has the labels defined therein
cy the perforations or slits 12, which are arrangea to
leave a skeletal waste, but in the arrangemenr of Fig.
5, the slits 12 define lines of weakeniny extending
across the entire width of the roll, so that the
individual labels 14 constitute the entire web without
any wastage. The feed and applicator apparatus ~or
handling this form of web may have to be modiEied as
there is no resulting skeletal waste, and if necessary,
the corners of the labels may be profiled as indicated
by reference numeral 34. The web 10 of the roll of
labels sllown in Fig. 5 is constructed in the same
manner as the web described in relation to Figs. 1 and
2.
In the arranger.lent shown in Fig. 6, a web 10 carries
printiny 16 which repeats at pitch lengths P, but the
web has no perforations or lines of weakening. The wen
defines contiguous labels which have to be cut from the
web by ~uitable cutting equipment located in the region
of the application head 36 so that individual labels
are cut fror~l the web immediately prior to or during
application of the label to the article 28 to which the
16 ~24~412
label is being applied. The individual labels can make
up the entire web as illustrated in the arranyement of
Fig. 5, or can be portions to be cut from the web as
indicated in Fig. 1, but in this arrangement also no
05 carrier sheet is required, as the web 10 will be
constructed in the same fashion as the web 10
illustrated in Fig. 1. Fig. 7 shows, in somewhat
~reater detail how labels in roll form as shown in Fig.
1 may be applied to box shaped products 40. rrhe roll
of labels is indicated by numeral 42 and is unwound
from this roll by a tractor unit 44 having a suitable
sprocket feed device which engages the holes in the
margins of the web 10 (the said holes are not shown in
the drawings) and is fed through a removal and
application station 46. The skeletal residue of the
web 10 is wound into roll fornlas shown by numeral 48.
The a~hesive side of the web 10 is the upper side and
all surfaces which contact this adhesive side are
required to be of a nature so as not to adhere to the
adhesive. Such surfaces may be defined by silicone
release material.
The removal and application station 46 comprises an
upper ~resure nip roller 50 (silicone coated) and a
lower vacuum cylinder 52 around which the web 10 laps
slightly as shown in Fig.7, and which has a plurality
of circumferentially spaced ports 54 which connect with
axially extendincJ passages 55, which are selectively
connectable to a source of vacuum or, when at
detachment position 56, with a blast of air under
pressure. A valve plate 58 at one end of the cylinder
controls the connection of the passage 55 to the source
OL vacuum and the blast of air in that said plate 58
has an arcuate port 60 coupled to the source of vacuum
and a port hole at position 56 connected to the air
under pressure. In use, tne cylinder S2 rotates in the
17 1248412
direction of arrow 62 whilst the plate 58 remains
stationery and each passage 55 which registers with
port 60 is connected to the source of vacuum. Each
passage 55 which leaves register with slot 60 arrives
05 first at position 56 where it receives a blast of air
under pressure, and then the passage is blanked off
until it once more reaches the port 60.
Operation of the unit 46 will be understood from the
above. The individual labels L are detached by the
vacuum at the nip between roller 50 and cylinder 52,
and travel round with the cylinder 52 until they reach
station 56 at which they are progresively applied to
the products 40 which are moving as indicated by arrow
63, in synchronism with the feed of the labels. To
this end the labels and products may be fed on an
indexing or continous basis, with interlinking controls
ensuring that the operation proceeds only when the
presence of a label and a product has been detected.
The arrangement shown in Fig. 7 could be modified to
handle a roll of labels such as shown in Fig. 6, which
are required to be cut from the web, and a suitable die
cutting means would be provided in the region of the
application station.
It is estimated that the apparatus shown inFig.7 will
be capable of applying labels at the rate of approx.
200/min in part because the label roll has no backing
strip.
Reference is now Made to Figures 8 to 11, which shows
methods of manufacturing labels according to the
invention.
Referring to Fig. 8 of the drawings, a roll 110 of
stock material in which la~els are to be formed may
18 ~.2~L84~2
suitably be of a width of 450 millimetres ana thickness
80 micron, the material may be a blo~,Jn f ilm
manufactured from a filled plastics material of the
nature set out in British Patellt No. 1,554,143, but in
05 any event should be a non-fibrous and substantially
non-extensible material. The web passes fro~n roll 110
throuyh silicone compound coating assembly 112 at which
release coating is ayplied to one side (the first side)
of the web, and then the web travels tt,rough a heating
10 chamber 116 which is ciivided into two compartments 118
and 120 by means of a horizontal partition 122. The
release coating is cured by passiny the weo back and
forth through the chamber 118 with the first side
initially face downwards then face upwards. The web
15 emerges from the chamber 118, after a traverse time of
20 seconds in an envirom~ellt maintaineci at 1;~0C, ana
the web is engaged by a pair of yuide rolls 124 and
126.
20 The web next passes through a pressure sensitive
adhesive coater assembly 128 of the form shown which
applies pressure sensitive adhesive composition t:o the
other and second side of the web. The web is led by
means of feed conveyor 130 into the upper neatiny
25 chamber 120 which i~ maintainea at 110C, in order to
drive off the solvents o~ the adhesive coatinys, to dry
same. The emergent web E~asses over guide rolls 132 and
134 (134 being silicone coated so ti~at it will not
sticl; to the adhesive side or the web which it
30 contacts) and then passes throuyh aie cuttiny rolls 35,
133 (138 being silicone coatea) which ~eLine tne
individual labels in the web, and the web is WOUlld into
roll 140.
35 Com}!ared to conventional methods of applyin~ silicone
coating to webs for the production of labels, che above
equipment is extremely simple an-:l can be operate by
~2484~. 2
19
convertors of raw material on an in-house basis, the
entire treatment having a cyle time of no more than
half a minute to one minute and the overall lenyth of
the apparatus being no greater than 8-10 metres. The
05 web material 110 will usually be pre-printed to define
the label printed matter, and the silicone composition
is applied over the printed side of the web. The
rollers 124 and 126 may be the rotary die cutting
rollers in order to define the individual labels in the
10 web by cutting through the web to define the labels but
also to leave catch points whereby the labels remain
connected to the web stock material until clisplaced
therefrom, instead of rollers 134 ana 136.
15 In the arrangement shown in Fig. 9, the silicone
release coating i6 an ultra violet curable ma~erial,
and therefore after the coatiny is applied, tne web is
passea throuyh an ultra violet dryer 140, which is
cluicker and less expensive than hot air drying. The
20 adhesive is applied and dried as before.
In the arrangement of Fig. 10, both the silicone
release coatiny and the adhesive are ultra violet
curable and therefore there are two ultra violet driers
25 140 ancl 142 respectively for the silicone release
coatiny and the adhesive, through which the web passes
in turn after application of the respective coatinys.
Fig. 11 shows an arrangement similar to Fig. 10 in that
ultra violet dryers are used. Only the path of travel
30 of the web is different. The parts of the apparatus in
Figs 9, 10 and 11 already referred to in Fig. 8 are
desiynated with the same referènce numerals. In each
of the arrangements shown in Fiys 8 to 11, the web
travels first through the silicone coater 112 anct
35 seconcl throucJh the adhesive coater. This order could
be reversed if desired. Also, an arranyement wherein a
UV dryer is u~;ed for the adhesive and a l--ot air dryer
~2~84~2:
is used for the release coating can be adopted.
another form of dryer which can be used at least for
the adhesive i5 a radio frequency dryer.
05 In the production flow path in any of the apEjaratus of
Figs ~ to 11, after the stage of a~plication of the
adhesive, all of the rollers which contact the adhesive
side are provided with a silicone coating in order to
prevent sticking of the rollers to the adhesive, and of
course it is possible in accordance with the invention
directly to wind the web 110 after the adhesive and
silicone materials have been applied in that the
silicone side of the web will not adhere to the
adhesive in the coiling and uncoiling of the web.
'rhe speed and simplicity of production is achieve~ ~i
selecting a web material which is non-fibrous and
therefore will not absorb excessive of amounts OL the
silicone material, which hap~ens when paper webs are
coated as in the conventinal method of produciny
adhesive labels.
The web 110 may be provided with apertures in the
margins thereof to enable the fee~ing of the web in the
apparatus for removal of the labels from the web for
application to articles before or after being coated.
The said apertures may also serve for the driving of
the web through the equipment shown in Figs ~ to 11.
When the silicone coating is heat cured, the
temperature at whicn the curing of the silicone coating
takes place will be dictated in fact by the material of
the web, tile s~eed of the web and the thickness of the
coating. Clearly, althouyh the curiny tinle can be
reduced by increasiny the curiny temperature, the
temperature cannot be so high as to cause
disirte~ratiol-~ oi the web material itself.
21 124~3~12
It is preferred that the operation will proceed on a
continuouc basis, but it can be arranged to take place
on a step by step basis witil dwell times during which
the silicone is cured ancl the adhesive is dried.
05
Any suitable form of pressure sensitive adhesive can be
used.
The thickness of the web can depend upon the
application, but typically labels are manufactured in a
thickness of approxirnately 25 to 250 microns, with the
filled plastics material web being typically 80
microns. The quantity of silicone coatiny which is
recluired for such labels typically would be as little
as 2 yms. per square metre, whereas with paper webs as
mucn as 40 gms. per square mctre may oe requirec.
As concerns the method of pro~uciny the labels, an
advantage of the preferred method of the invention
resides in that the polymerisable release coatincJ,
which may be a silicone compound, can be polymerised in
a relatively short time by virtue of the fact that the
substrate web r.laterial i~ non-fibrous and therefore
will not absorb the release coat material when applied.
This means that only a fraction of the an,ount of
release coat material normally applied will be used (as
little as S~ as compared to the conventional method)
and correspondingly the curing time is significantly
reduced. I~ith a slow curing time, correspondincJly
simpler ancl therefore smaller machinery can be employed
for the manufacture of the labels.
Tests usin~ a silicone release coatincJ material applied
in aMounts of 2 gm/sq metre have shown that lO seconds
in a chamber lleated to 120C achieves satisfactory cure
of tne silicone release coat material.
- 22 - ~248412
SUPPLEMENTARY DISCLOSURE
1 Fig, ~ is a part-sectional side view of apparatus for
applying adhesive to a roll of labels;
i~
Fig. ~4 is a side view of applicator roll shown in
Fig. ~;
1~
Fig, ~ is a perspective view of the apparatus shown
in Fig. ~, and
Fig. ~ is a diagrammatic side elevation of the adhesive
supply circuit.
The principal components of an adhesive coating unit
for coating the label stock web are illustrated in Fig.
. The applicator roller 74 is shown as are two guide
or path rollers 72 and 76, The application roller 74 is
located vertically above a trough roller 194, and the
application roller 74 and trough roller 194 are adhered
together by gears 196, 198, respectively secured to the
shaft of said rollers. The application roller is carried
on a lever arm 200 which is pivotable by means of an air
cylinder 202 through a crank 204 connected between the pis-
ton of the air cylinder and the lever 200 so that the app-
lication roller can be raised clear of the trough roller
194 so as not to pick up any adhesive therefrom when ad-
hesive pick-up is not required.
The path rollers 72 and 76 guide the base material 32
into small arcuate contact with application roller 74, but
each of the path rollers 72 and 76 can be raised and lowered
by means of pneumatic cylinders 206 and 208 respectively.
Cylinder 206 acts directly on roller 72 to raise and lower
sam,e, whilst cylinder 208 acts through a bell crank lever
ZIV.
The function of the adhesive coating unit is to apply
an even layer of water based adhesive to the material 32,
and although not shown in Fig, ~3, there is a tray contain-
ing the water based adhesive material and into which the
roll 194 dips in order to pick up the adhesive.
~.
~248412
- 23 -
1 Additionally, there are doctor blades 210 for removing
adhesive along the peripheral rings on the application
roller, so that the adhesive will be applied to the web 32
only if desired at strip locations. In this connection it
has been mentioned that the adhesive is removed from the
application rollers so that the adhesive will not be applied
over the sprocket holes in the base material. As many
doctor blades 210 as required will be used for this purpose,
depending upon the number of rolls of labels which are formed
in the base material 32.
Additionally, there is a meyerbar 212 located at the
top of adjustable pedestals 214 so that the meyerbar will
contact the adhesive coated surface of the material 32 by
a process to be explained.
Trough roller 194 and application roller 74 are 3
directly driven by means of motor 216 as shown in Fig. ~,
which is geared to the shaft of the trough roller 94 by means
of gears 218 and 220.
The adhesive system for the adhesive coating unit is
shown in Fig. ~, and will be seen to comprise a stain-
less steel tray 222 containing the adhesive and into which
the trough roller dips. The tray is equipped with a pump
224, a filter 225, and a pipe system 228 and 230 to enable
the adhesive to be replenished during normal operation from
an adhesive reservoir 232. The pipe 228 is connected to
a water supply to enable the addition of water to the ad-
hesive reservoir, and shut-off valves 232 and 234 are provided
in the pipes 230 and 228 for control purposes.
An overflow 236 from the tray 222 leads to a down pipe
238 which returns overflow adhesive to the adhesive
reservoir 230.
The meyerbar 212 controls the amount of adhesive applied
to the base material. The meyerbar is a small diameter wire
wound rod (similar in appearance to a threaded bar). The
weight of the coated adhesive applied is directly propor-
tionate to the meyerbar wire size, and any suitable size of
~248at~L2
- 24 -
1 meyerbar may be used depending upon the application. During
operation the meyerbar is driven by an air motor and rotates
in a direction against the flow of the material. this con-
traflow rotation scrapes up excess adhesive into a tray
located under the meyerbar.
During normal operation the tray 222 is half full of
adhesive and is in an elevated position. The roller 194 is
partially immersed in the adhesive and as it turns it trans-
fers adhesive to the application rollers 74. Path rollers 72
and 76 are in a down position allowing the material to run as
shown in Fig. ~3 in contact with the application roller. As
the base material 32 moves through the unit it is charged
with adhesive by the application roller 74 and then passes
to the meyerbar 212 where the rotating meyerbar removes
excess adhesive and the adhesive coated base material con-
tinues from the path roller 76 to a radio frequency dryer
unit (not shown). When it is necessary to stop the adhesive
coating operation, the path rollers 76 and 72 raise the
material away from the application roller 74. This is
achieved by a control system as a two-step function. The
roller 72 is raised first, followed by the raising the roller
76. This ensures that all the adhesive applied to the
material 32 is scraped by the meyerbar.
/4
Reference is also made specifically to Fig. ~ which
shows the label stock material 32 and how it is provided
with edge sprocket holes 32A. This figure also shows the
evenly pitched labels 32B which are printed on the web 32
at regular intervals and in registry with the sprocket holes
32A. The figure also shows clearly the meyerbar 212 and the
guide roller 76, and an additional guide roller 76A has been
shown in order to indicate the reverse side of the web 32
and on which the adhesive strip 85 is applied. The width of
the adhesive strip is as described herein set by the doctor
blades ~, which are adjustable axially of the roller 74 to
ensure that adhesive does not come into contact with the
underside of the web 32 in the region of the sprocket
holes 32A.
~48~2
- 25 -
1In the arrangement illustrated in Fig, ~, only a
`-1 sample row of labels 32B is indicated, but the web may
be printed with parallel rows of labels, and they will
be twin rows of sprocket holes between adjacent rows or
labels so that when the web is eventually cut into
individual rows there will be sprocket holes to each side
of each roll of labels. Again appropriate doctor blades
may be used to ensure that the adhesive strip 85 which
is applied to each roll does not extend to the sprocket
holes at the web edges.
It will be seen that the adhesive application unit of
the supplementary disclosure presents a number of signi-
ficant features, namely that the adhesive is put on by
an applicator roller in amounts more than required, and
subsequently is scraped by the meyerbar. Additionally,
when the operation is to be stopped, steps are taken to
ensure that the material is removed from the application
roller in a particular fashion to ensure that all applied
adhesive is scraped by the meyerbar.
