US 2940196 A
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June 14, 1960 M. SCHOR 2,940,196
STRIPPABLE LABEL Filed Aug. 15, 1958 INVENTO Alt/fan Jc 0 TTORNEYS United States Patent STRIPPABLE LABEL Milton Schor, Havertown, Pa., assignor to A. H. Wirz, Inc., Chester, Pa., a corporation of Pennsylvania Filed Aug. 15, 1958, Ser. No. 755,259
1 Claim. (Cl. 40-2) The present invention relates to collapsible tubes provided with strippable labels, to methods of producing strippable labels on collapsible tubes, and to compositions for use in such labels.
A purpose of the invention is to obtain better strippability of strippable labels on collapsible tubes and the like, especially at low plasticizer contents, and under low temperature conditions, and generally to improve strippability.
A further purpose is to produce a strippable label which has better wetting properties for label printing ink, which adheres better to the ink, which permits the ink to dry faster, and which makes the ink more resistant to smudging especially immediately after printing.
A further purpose is to improve the low temperature flexibility of a strippable label, so that it will remain in intimate contact with the metal of the collapsible tube and conform to the collapsible tube when it is squeezed or otherwise pinched in normal collapsible tube use, but will still, at temperatures likely to be encountered in service, readily strip and peel from the collapsible tube.
A further purpose is to produce a strippable label on a collapsible tube or the like which is more resistant to soapy water, more resistant to moisture and more re sistant to alkali.
A further purpose is to secure a strippable label which is more resistant to scuffing and abrasion and generally tougher.
Further purposes appear in the specification and claim.
in the drawing I illustrate a collapsible tube provided with a strippable label which has been printed with label information, and embodies the principles of the invention.
The single figure'illustrates such a collapsible tube in perspective.
Describing in illustration but not in limitation and referring to the drawing:
In accordance with my United States patent application Serial No. 372,963, filed August 7, 1953, for Strippable Label and Method, now Patent No. 2,855,707, issued October 14, 1958, I illustrate and describe a strippable label which is provided on a collapsible tube and is useful especially in the pharmaceutical trade to permit the retail pharmacist to remove the label where required without the diihculty and annoyance of soaking and re moving a paper label, or optionally to sell the produce over the counter and allow the label to remain and identify the product to the consumer.
There may be many reasons for requiring optional removal of a label. It may be desired to sell the product on a prescription and provide information or instruc tions which are peculiar to the particular patient. It also may be desired to avoid transmitting to the patient information which appears on the original label, as for example, so as not to unduly alarm the patient, or create some misapprehension in the mind of the patient from the initial label information.
Accordingly, strippable labels having information printed thereon have been supplied on several million collapsible tubes.
The present invention is concerned with the improvement of strippable labelling, overcoming certain deficiencies and difiiculties which have existed in the prior art.
By the present invention it is possible to produce plastic labels capable of application to collapsible tubes or the like by spraying, dipping or roller coating, which remain in intimate contact with the surface of the collapsible tube when the collapsible tube is pinched or squeezed, but which have definitely improved properties in several other respects. One important feature of the present invention is that the desired properties can be obtained with smaller plasticizer contents. This aids in getting better ink adherence due to increased wetting of the film to ink, faster drying of the ink, and greater resistance of the ink to smudging, especially immediately after printing by roller printing methods.
It is also possible by the invention to greatly improve the strippability of the label at low temperatures, down to as low as zero degrees F. and even much below this temperature. In the prior art practice the tendency has been for the labels to become less easily strippable at low temperatures, but this is not true of the preferred composition in the present invention.
The invention also makes possible the production of strippable labels which are more resistant to abrasion and sculfing incident to shipment, sale and use.
The invention also assures that the label will tend to remain intimately associated with the collapsible tube when the collapsible tube is pinched, bent or rolled even down to very low temperatures, well below zero degrees F.
Another important aspect of the invention is that the strippable labels have greater resistance to moisture, to soapy water,'to alkalies and to chemicals generally. They resist'sunlight and weathering, and are resistant to fungi. They resist grease and perspiration.
In accordance with the invention, the collapsible tube, which should be preferably warm and dry, and may be unlabelled or provided with the usual adhering rotary printed label, is coated with a layer of resin in accordance with the invention, using preferably roller coating techniques, but permissibly dipping or spraying.
At the time the label is applied, the end of the collapsible tube which is to be crimped is open and the collapsible tube is truly cylindrical and normally positioned on a cylindrical mandrel. The collapsible tube after coating is normally carried through a dryer at elevated temperature, suitably in the range from to 400 degrees F., although the collapsible tube can dry in air at ambient temperature. The drying time is 255 degrees F. is preferably about 10 minutes.
After drying, the strippable label on the collapsible tube desirably has a thickness from 0.0004 to 0.001 inch.
Once the strippable label has dried, the strippable label is rotary printed, desirably using the usual collapsible tube printing techniques, and applying any suitable label information, such as the name of 'the product, the instructions for use, the dosage, the makers name, and the like. One of the great advantages of the present invention as already mentioned is that the usual label printing inks adhere better, dry faster and are more resistant to mudging when applied on the strippable label of the present invention.
The basis for the strippable label of the present invention is a copolymer of vinyl chloride and vinyl acetate of medium molecular weight. A preferredembodiment contains about 10 percent by Weight of vinyl acetate, and has a molecular weight of about 90,000. The range of vinyl acetate is suitably from 7 to 13 percent,
-in the process of drying of the strippablelabel. preferred solvent is'isoph'orone. I' can however use other 1 solvents, including any of the recognizedketone solvents, -su'ch as methylethyl ketone, iethyl 'butyl'k'eto'n'e, and
' 'the"bal'ancebeing'vinyl'chloride, copolymerized. A desirable form of this'material is -E-xon-450; made-by Firestone Tire and Rubber Company, containing about per-' cent vinyl acetate.
'-In-addit-ionto-the'copolymer-resin referred to, I use as a plasticizer a dialkyl sebacate, having; a carbo'n iehain length' between 6and20 carbon atoms, and mo'st desirably "dio'cty' l sebacate. Oth'er examples are dioctadecylsebadate and didodecyl sebacate;
The quantity of plasticizer used based on the weight of the. copolymer resin will vary from 10 to 75 percent and will preferably be in the range from 10 to=24 percent and most desirably from to 24-percent, theoptimum being about percent. a
In addition I use a solvent which of course evaporates The methyl isobutyl ketone'. I can also 'use dirneth'yl formamide, nitrofuran. and 1 nitroparafiin. Where the odor is not objectionable, .1 can -use cyclo'hexanone.
' As a means of reducing the expense, I- can Where'desired incorporate a solventdiluent, a preferable form being super high flash naptha, which desirably has akauributanol factor of 95 and a boiling point for 20 percent of thec o'ntent at 350 degrees F. v
In making up the composition, the copolymer resin and the plasticizer are'incorporated'with the solvent and the solvent diluent. It is usually necessary'to mixunder mechanical agitation for a time of the order of one-half hour before the ingredients are'thoroughly dissolved. -It
. "is not however'ordinarily necessary to use heat'for solution. I illustrate in the drawing a completed collapsible tube according to'the invention. The tube -2 0 has a generally cylindrical body 21, afdischargeend 22 which 'receives'a cap, a shoulder 23 and anopposite pinched end closure 24. The body. issurrounded by a strippable label 25 produced "in accordance with the inventionrand having rotary printed thereon labelling information '26.
The'relation of the collapsible .tube to the strippable label is unusual. When the solvent evaporates the coating 7 which form's'the strippableilabel shrinks and draws itself smooth into intimate."contacti'with; the iout'er surface of theibody of'the collapsible tube. Anintirnate asso- Iciation between the coatingiandthe collapsible tube occurs, sin'ce;when the user squeezes or" presses the collapsible tube and bends .it' or' fiattens it down, the label conforms to and remains. against the metal surface of the collapsible tube, and does not'detach itself from or bag away fromthe collapsible tube.
V label does not have appreciable adhesion to the collapsible tube because when the .user desires to detach the label he merely needsto rip it with hisfinger nail or withan instrument as shownat 27, and the labelwill readily peel away from the collapsible tube. and will permit com- On the other .hand, the
plete removal'of the label. Underneath the collapsible tube surface or itsrlabel is 'clean 'andfree from any .strippable label material.
As already explained, the capability of the'label-of re- 1 "maining with the. collapsible tube nwhen the collapsible tube is pinched-at low temperature-is greatlyimproved in the present invention, especially when the sebacates are used as plasticizers.
Furthermore, the collapsible tube provided. with the label can be washed in soapy Water, or alkaline'detergents -without danger of harm to the label or ,theprintin'g.
I In some cases it is desirable toy-render the strippable label opaque, and this can be done by, pigment, which 7 should preferably be inserted toa concentration of'about two pounds per gallon of the coating liquid, suitable pigments being paint grades of titanium. dioxide, barium sulphate, lithopone, iron, oxide, chromic oxide, phthalocy- V vanine green orblueorthelike I 4 i The following examples are typical of clear strippable label formulas in accordance withthe present invention:
. Examp I" Copolymer-of-vinyl. chloridefa'nd vinyl acetate ,The compositions of these various materials all arouse fill in accordance with the present invention, but they differ somewhat in theparticularpr'operties when used for strippable materials.
Example I with the low content of plasticizer is more diflicult to start stripping because of greater resistance to penetration, but once stripping begins it strips very easily and cleanly, andu'sua'lly in one piece: On the other hand, the formulation of Example II and particularlythe formulation of Example III penetrates more easily to; start stripping, but once strippingbegins the composition has'more the consistency of chewing gum,
is likely to separate in several pieces and therefore is likelyto'take longer to strip. I
As far as ink adherence (printability) isconcerned, this is better with the composition of Example I than it is with the composition of Example III.
' The resistance to moisture, soap and alkali are slightly better for Example I than for Example III.
' On the other hand, the low temperature flexibility in case the collapsible tube is squeezed at low temperature is somewhat better with Example III.
In some cases it is preferable to printthe collapsible tube :in the normal manner first with label information, and
then to apply thestrippable label over the printed collapsible-tube'and'then subsequently print the strippable label with different label information. Then the retailer can select Whether he will leave the strippable label in place or remove it prior to sale. In some casesthis procedure can be applied over only a'portion of the'length of the collapsible tube, using the 'st'rippablelabel "to mask only a partial printed label. i
In'view of my invention: and disclosure variations and modifications to meet individual whim or particular need .will doubtless become evident to others skilled in the art,
to obtain 'all or part of the benefits of my invention y without copying the product and method shown, and I,
therefore-claim all such insofar as they fall within the reasonable spirit and scope ofmy claim.
Having thus described my invention, what- I claim as new and desire to s'ecureby Letters Patent is:
In combination with a collapsible tubular inetal Icontain'er. having a body, an end adapted to be closed by crimping, and an oppositedischarge end, a thin coating of a filmfo'rmi'ng resin composition extending entirely around the-body of said tube between the opposite ends of said a tube and terminating'l'en'gt-hwise short of at least one of said ends, said coating itself remaining intimately associated with the metal surface of said tube throughout the-area ,ofth'e tube covered by said coating and being capable of remaining intact when the tube and coating are 5 6 deformed at the same point, said coating further having 6 and 20 carbon atoms, combined with the sehacic acid peeling properties when broken, lifted, and pulled, said group, as a plasticizer. coating having printed matter on the outside surface thereof and accordingly serving as a label until broken References Cited in the file of this patent and peelably removed, and said coating consisting of a 6 copolymer of vinyl chloride and vinyl acetate, and from UNITED STATES PATENTS 10 percent to 24 percent on the weight of a long chain 2,825,159 Schor 1,958
dialkyl compound having a carbon chain length between 2,855,707 Schor Oct. 14, 1958