Coating processes – Direct application of electrical – magnetic – wave – or... – Polymerization of coating utilizing direct application of...
Reexamination Certificate
2002-05-31
2004-09-28
Pianalto, Bernard (Department: 1762)
Coating processes
Direct application of electrical, magnetic, wave, or...
Polymerization of coating utilizing direct application of...
C427S208400, C427S208800, C427S288000, C427S386000, C427S387000, C427S407100, C427S516000, C427S521000, C427S553000, C427S557000, C427S558000, C427S559000, C427S595000, C156S060000
Reexamination Certificate
active
06797333
ABSTRACT:
BACKGROUND
Pressure-sensitive labels have become almost ubiquitous in modern society. As only one example, they appear on the vast majority of all shipped packages. They are also used to identify parts in manufactured goods and manufacturing equipment. Another example of a very large pressure-sensitive “label” is shelf or drawer liner sold as “Contac®” paper.
As another instance of the use of pressure-sensitive labels, baggage tags (or more commonly “bag tags”), have become unavoidable, certainly in the vicinity of commercial airports. The airlines affix the tags to passengers' luggage to indicate both the destination of the articles as well as the items' owners. To include this information, airlines actually print tags when a passenger appears for a flight. The attendant then takes the printed tag, removes a liner sheet, slips it through the handle of the luggage, and adheres it to itself. If the parcel has no handle, such as a carton, then the tag simply sticks directly to the item.
The construction of a typical pressure-sensitive label currently in use appears in FIG.
1
. There the label, indicated generally at
11
, includes the face sheet
12
upon which appears the desired printing
13
. In the case of a shipped package, the information identifies and locates the shipper and the recipient. For the example of bag tags, the printing may not only identify the bag's destination and owner, but will usually indicate the airline on which the passenger commences his or her journey. The airline identifier (and logo) typically arrives preprinted on the tag when delivered to the carrier by the tag's producer.
The face sheet generally has a composition of paper or plastic. The information
13
for a general label can be placed on it by a computer's printer or any suitable device.
For a bag tag, the identification of the bag's destination and owner can only be placed on the tag
11
at the airport. To accomplish this printing, many if not most, baggage tags' face sheet
12
have a thermally printable composition. Suitable thermally-printable papers are provided by Appleton Papers Inc. of Appleton, Wis., and by Ricoh Electronics Inc. of Santa Ana, Calif. Each of the baggage stands then possesses a thermal printer which, through the application of heat, places the necessary information on the tag's face sheet
12
.
Accordingly, the process described below will produce label stock for a very wide range of pressure sensitive labels. Most labels may utilize ordinary paper or plastic as the face sheet
12
. Bag tags can employ the direct thermal printing process described above.
In addition, the indirect thermal printing process, as opposed to the direct thermal, process described below, uses ordinary, but smooth, paper as the face sheet
12
. The thermal printing head actually applies the heat to a ribbon which contains ink. The heat releases the ink from the ribbon which deposits it on the face sheet to produce the printing.
With the information
13
on the face sheet
12
, the operator removes the liner sheet
15
from the adhesive
16
on the backside of the face sheet
12
. With the adhesive
16
exposed, the user places the face sheet
12
with the adhesive directly on the package or the equipment. Dyna-Tech Adhesives Incorporated of Grafton, W. Va. provides a suitable general-purpose adhesive under the designation DyTac 2057. This adhesive has a composition of a styrene-butadiene polymer and constitutes an organic phase dispersed as an emulsion in an aqueous phase.
For a bag tag, the airline personnel places part of the tag through the bag's handle and sticks the adhesive to a portion of the tag which still the liner sheet attached. Sticking the adhesive to the remaining liner forms a loop of the tag around the handle. Alternately, if the bag or parcel has no handle, the attendant removes all of the liner
15
from the tag
11
and sticks it directly to the item.
In either event, the liner must remove virtually completely from the adhesive so that the latter can facilely attach to another surface. If portions of the liner
15
, typically composed of paper, remains on the adhesive
16
, then the covered adhesive would not achieve a secure affixation of the label to its item. In the case of bag tags, the resulting dislodged tag would create a lost bag to the distress of both the passenger and the airline.
To achieve a clean separation of the liner
15
from the adhesive
16
, the former carries the silicone coating
19
attached to it. The coating
19
, firmly affixed to the liner
15
, presents a smooth, relatively nonadherent surface to the adhesive
16
. Pulling off the liner
15
with its silicone coating
19
results in a clean, sticky layer of adhesive
16
attached to the face sheet
12
. Stated in other words, the silicone coating
10
, affixed to the liner
15
, permits the release of the adhesive
16
from itself and thus the liner
15
. This leaves the face sheet
12
with an exposed layer of adhesive
16
.
The manufacture of the label
11
generally commences with the coating of the paper liner
15
with the silicone
19
. A type of silicone finding frequent use in this day of environmental concerns takes the form of a UV curable silicone polymerizable liquid. Use of this category of silicone avoids the problem of evaporating hydrocarbons into the atmosphere. Curing the liquid silicone entail shining it with UV radiation. This causes the silicone monomers to combine, leaving a unified mass of silicone coating
19
firmly attached to the liner
15
. Blissfully, the process places substantially no pollutants into the atmosphere.
Suitable components for UV-curable silicone solutions are supplied by Rhodia Inc. of Rock Hill, S.C. A liquid for an easily releasable layer may include 100 parts of UV-curable silicone polymer (Rhodia product PC-600); 2.5 parts of cationic photoinitiator (PC-702); and CRA-minus release modifier (PC-670). The silicone itself has a composition of an epoxy-modified polydimethylsiloxane. This type of compound comes from the class of epoxy-modified polysiloxanes which may well provide other suitable moieties.
For a silicone layer with a tighter release, the above solution may include 5 to 55 parts (depending upon the desired characteristics of the silicone layer) of CRA-plus release modifier (PC-680). Free radical photoinitiators may alternately find use in appropriate solutions.
Promptly after receiving the UV radiation, the silicone
19
cures into a reasonably hard mass firmly affixed to the paper liner
15
. However, it cannot then receive the adhesive
16
, Placing the adhesive onto the newly cured silicone layer
19
will cause these two layers
16
and
19
to stick together. This represents a clearly unacceptable situation. Instead, to avoid this clearly deleterious situation, the silicone layer
19
must sit on the liner
15
at least several hours if not a whole day before contacting the adhesive
16
to avoid the unacceptable results indicated above. The necessity for delay seems remarkable in light of the fact that the newly cured silicone seems hard, smooth, and ready for further use. In fact, during the delay, the silicone-coated liner can be wrapped into a large roll and, after the delay period, unrolled and used without displaying any negative effects.
In fact, rolling the liner with the newly cured silicone into a large cylinder represents the usual manufacturing process. Simply stated, the liner with the new silicone coating cannot remain on the manufacturing equipment and render it useless for the time required for the silicone to remain out of contact with an adhesive. Accordingly, the usual manufacturing process involves a machine placing the uncured silicone on the liner
15
. The silicone undergoes UV curing. Then the machine rolls the liner
15
with the cured silicone layer
19
onto a roll, which is removed from the machinery and left to sit for the substantial period of time necessary to render the silicone substantially less adherent to the adhesive
16
. After the delay period, t
Haase Roger L.
Walliser Carl J.
Friedman Eugene F.
Print-O-Tape, Inc.
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