US1935708A - Wrapper and method of making the same - Google Patents

Description

l. GURwlCK 1,935,708

AND METHOD OF MAKING THE SAME Nov. y2l, 1933.

l xNvENToR Wvmg Gurwxc ATTORNEYS Patented Nov. 2l, 1933 PATENT 4oi-Flcls WRAPPER AND METHOD OF, MAKING THE SAME i Irving Gurwick, New York, yN. Y., assignor, by mesne assignments, to Shellmar Products Company, Chicago, Ill., a corporation of Delaware 4 Application March 22, 1932. n erial No. 600,415

8 Clams. (Cl. lOl- 226) This invention relates to blanks or wrappers used for packaging goods, and more particularly to printed blanks or wrappers made of regenerated cellulose paper and to a method for making the same. l

A type of wrapper for packaging goods for visible display and sale. which has proved to be exceedingly popular in recent years, is a transparent cellulose paper made, for example, from regenerated cellulose. This paper is lustruous 'and preferably transparent, and further is greaseproof, that is, non-absorbent with respect tovoil or grease. However. it tends to be hygroscopic and to absorb moisture, particularly at exposed edges thereof. Typical examples of this paper are the products commercially sold and known under the trade names Cellophane and Sylphwrap.

Despite the ,popularity of this wrapper for Wrapping small articles, such as candy bars and the like. considerable difficulty has arisen when attempting to use the same with automatic wrapping machines or similar machinery in which the sheets must be withdrawn singly from a stack -of sheets by appropriate automatic feed mechanism. Such feed mechanism may, for example,

remove the top sheet of the stack by suction.

In practice, it is found that very often more than a single sheet is withdrawn by the feed mechanism. This is true even with plain sheets, and the condition is aggravated when the sheets are printed as by means of oil or varnish colors which dry by oxidation.

The primary and general object of the present invention is to overcome the foregoing difficulty, and to provide a Wrapper which will not be sticky or tacky, and which will permit of free separation of stacked sheets, particularly when used in automatic machinery. I have found that the undesirable tackiness of the plain cellulose sheets is due to the absorption of moisture at the exposed edges of the sheets in the stack. for these edges after absorbing 'a Slight amount of mois A'such other objects as may hereinafter api ear,

ture from the air, tend to stick one to the other. I have further found that if the sheets are printed with oil colors or varnish colors or similar inks which dry by oxidation, the printed matter, probably because of the grease-proof nature of the paper, does not dry completely bone-dry, but tends to remain permanently tacky. In accordance with features and objects ofthe present invention, I overcome the first difficulty by providing the edges of the wrapper'with a border made of a bone-dry water-proof color. This border being interposed between each of the successive wrappers, prevents the samejrom sticking together. I further find it desirable to make any other printing on the sheet, if additional printing is required, also of a bone-dry Water-proof color or ink. By these precautions, thetwo Ways in which the sheets tend to stick together are counteracted, and the wrappers remain permanently freely separable and successfully usable by automatic machinery.

The desired bone-dryness of the printing is not obtainable by heating the sheet after printing,` because the cellulose paper is itself damaged by heating. In accordance with further objects and features of the present invention, the printing is done with a lacquer color which dries at a low temperature, say, 70 F. Such color is so volatile and dries so rapidly that it is difllcult to use the same on ordinary printing-plates or cylinders; .and accordingly, I perform the printing operation on a gravure or intaglio printing cylinder. .This permits the deposition on the sheet of a solid body of color which nevertheless may be air dried at low temperature, particularly if the sheet is exposed to a high velocityblast of air.

If the sheet is printed as aforesaid without the use of a border, the edges tend anyway to adhere, due to absorption of moisture, as has a1- ready beenpointed out. It is evident that a similar result may take place if the border is spaced appreciably from theedges of the sheet. Accordingly, it is a further object of the present invention to bring the border as close to the edges of the sheet as possible, and to accomplish this the border is preferably made a bleed border, the web of cellulose paper being prelim- 'inarily printed with borders of excessive width,

and the desired wrappers being subsequently cut from the web by severing the web in the printed border, the edge of the border thus being made coincident with the edge of the sheet.

To the accomplishment of the foregoing and my invention consists in the printed cellulose wrapper and method of producing the same, and their relation one to the other as hereinafter are more particularly described in the specification and sought to be defined in the claims. The specification is accompanied by avdrawing, in which: I

Fig. 1 is a partially sectioned elevation schematically showing one way of practicing the method of the present'invention;

Fig. 2 is a plan view further explanatory of and the web 4 withdrawn therefrom is passed through printing apparatus, generally designated 6, then through a drying tunnel 8, after which the desired blanks or wrappers are cut from the web by appropriate cutting mechanism generally designated 10.

The web 4 is made of regenerated cellulose paper and is lustrous, grease-proof, and transparent. This` shiny transparent paper is exceedingly popular for use in wrapping or packaging goods for display and sale. While greaseproof and non-absorptive to oily substances, it is hygroscoplc and tends to absorb moisture particularly at the exposed edges thereof. Consequently, when blanks of this paper are stacked, the exposed edges absorb moisture and become tacky and tend to stick together. Meanwhile, if the sheets instead of being plain, are printed with an oil or varnish color, the color remains tacky for an indefinite period because of the nonabsorptive nature of the paper, and ,this increases the adherence of the stacked sheets.

In accordance with the present invention, the

web 4 is printed with lacquer color a body of which is indicated at 12 in a color bath 14. This lacquer color is selected to dry at a low temperature, say F. or ordinary room temperature. Lacquer colors which must' be dried at higher temperatures, say, 160 F., are preferably avoided because the cellulose paper here dealt with is injured by such increased temperatures.

The rapid-drying, highly volatile, low temperature lacquer is difdcult if not impossible to use with an ordinary printing plate or printing cylinder because it dries before it can be applied to the paper, and in no case could a solid body of color be obtained such as isY desirable when working on transparent paper. In accordance with the present invention, the printing is preferably done on a gravure orv intaglio printing cylinder 16 which runs in the body of color 12 and has excess color wiped therefrom by an appropriate doctor blade 18. The printing mechanism will not be described in detail, as it forms no part of the present invention,y but for further information the .reader is referred to my Patent No. 1,867,405 granted July 12, 1932' and entitledy Intaglio printing". As is there explained, the cylinder 16 is preferably deeply etched and is used in cooperation with a pressure roller 20 which applies a relatively feeble pressure on the paper in order to prevent l squeeze-back of the rich body of color being applied to the relatively non-absorptive stock. To obtain accurate synchronous feed of the web, feed wheels 22 are used in conjunction with a feed roller 24. the said feed wheels 22 being rotated in proper synchronism with intaglio cylinder 16 and being applied solely to the extreme and preferably unprinted margins of the web.

The web is then fed upwardly to drying tunnel 8, it being guided through an entrant slot 30 by roller 32 and through an exit slot 34 by roller 38. A- relatively heavy blast of air at ordinary room temperature is forced through tunnel 8 from the end 38 toward the discharge end 40.

The tunnel is preferably confined in area so as to give the air a high velocity over the traveling web, thus serving to rapidly dry the web to the necessary bone-dry condition.

Referring temporarily to Fig. 2, it will be observed that the web 4 is printed with longitudinal borders 42 and transverse borders 44, the said borders serving to outline the sheets or wrappers of desired size. If .additional printed matter is desired, such as advertising insignia or the like, such printed matter may readily be applied during the previously described printing operation and is here exemplified by the diamond-shaped central area 46. Furthermore, if the sheet is to be printed in several colors, the printing and drying operation previously outlined may be repeated in order to obtain the desired multi-color design, this operation being described in'detail vin my patent heretofore referred to.

The web printediwith borders, as described, is next cut intowrappers of desired size. In the present case the web is first trimmed longitudinally and then severed transversely. The longitudinal trimming means may consist of stationary cutters, or of rotary cutters here indicated at 48. Cutters 48 in cooperation with a roller 50 trim the edges from the web, leaving the scrap or discarded margin 52 best shown in Fig. 2.. It is important to notice that the knives 48 are preferably located within the printed border 42 so that part of the printed border is cut away, as shown at 54, while the remaining border 56 extends completely to the edge of the paper and constitutes in effect a bleed border.

The thus trimmed border is next severed transversely to form the individual sheets. This operation may be performed by a rotary knife or a guillotine knife or, as is here illustrated in Fig. 1, may be performed by a movable guillotine knife, the blade 60 being reciprocated both vertically and horizontally by eccentric 62. The lower knife 64 is reciprocable only in a horizontal direction, it being guided by stationary rails 66. The lower knife is moved horizontally with the upper knife by reason of interconnecting dowel pins 68. With this arrangement the knife moves with the traveling web during the cutting stroke, so that the movement of the web may be kept continuous rather than intermittent.

As is best shown in Fig. 2, the transverse severance of the web by means of knife 60 is timed so that it takes place in the middle of the transverse borders 44, thus making bleed borders 70.

When the wrappers or blanks printed with bleed borders 56 and 70 are stacked one above the other, the arrangement is somewhat as shown in Fig. 3, the illustration being to an exaggerated scale for the sake of clarity. The sheets 72 are separated at their edges by bleed borders 56. These bleed borders are made of waterproof ink and are bone-dry. It follows that even if the sheets 72 absorb moisture at their edges and tend to become sticky or tacky on one side, they nevertheless are separated from the next adjacent sheets by a thin layer of water-proof material and therefore are prevented from adhering one to the other. In practice, I find that sheets printed in this manner remain permanently separable without effort, and therefore are especially well adapted for use in machinery involving automatic feed mechanism which must pick up a single sheet at a time. A frequent example is wrapping machines and the like provided with ysuction feed mechanism.

The borders are preferably bleed borders in orety der to prevent cohesion of the edges of the sheets outside of the borders. However, it is obvious that if the border is brought reasonably close to the edge of the sheet, the sheets will not stick together even if the borders are not bleed borders. Thus, referring to Fig. 4, the sheets 74 are separated by borders 76 corresponding to borders 56 but spaced slightly from the edges of the sheets. It is evident, from an inspection of Fig. 4, that if this spacing is small, the edges of the sheet are unable to come into suiciently intimate contact and pressure to cohere. This fact is pointed out because in some cases it may prove inconvenient to. provide a longitudinal border 42 which is subsequently trimmed to form longitudinal bleed borders 56. In other words, in some cases it may prove desirable to print the original longitudinal border 42 as closely as conveniently possible to the edge of the web and to thereafter sever the web only in a transverse direction.

i Obviously, the transverse severance may be and preferably is in all cases made a bleed border because no additional complication is introduced in so doing. By making the longitudinal border exceedingly close vto the edge, say,

several hundredths of an inch therefrom, the

longitudinal trimming operation may be wholly dispensed with, and the appearance of the sheet will not be changed. It is also possible to space the border, say, a sixteenth of an inch from the edge, on all sides, with satisfactory results, but for best results the use of bleed borders lis preferable.

The improved blank or wrapper of my invention and the preferred method of making the same, as well as the many advantages thereof, will, it is believed, be apparent from the foregoing description. The wrapper may be stacked and compressed as desired, and nevertheless has no tendency to adhere to the adjacent wrappers. The blanks slide over one another freely and may readily be separated by ordinary feed mechanism used in automatic machinery. The border overcomes any difficulty due to the hygroscopicity of the edges of the cellulose paper, while the use of bone-dry lacquer colors prevents any tacklness by reason of the printing itself. The desired complete dryingof the web is obtained without heating the web or otherwise weakening or injuring the same. The border is preferably brought as close to the edge of the sheet as possible, and in accordance with my preferred method is made coincident with the edge of the sheet in the form of a bleed border.v All of these results are 0btained despite the difficult nature ofthe stock being handled, for the regenerated cellulose paper is lustrous and does not absorb the printed color, and therefore necessitates special precautions if a bone-dry non-tacky product is to be obtained.

It will be apparent that while I have shown and described the method of my invention and the product obtained thereby in preferred form, many changes and modifications may be made in the method and product disclosed, without departing from the spirit of the invention, defined in the following claims.

I claim:

1. The method of preventing a stack lof blanks or wrappers made of lustrous, grease-proof, transparent cellulose paper from becoming tacky due to hygroscopic absorption at the edges thereof, which includes printing a bleed border on all of the edges of the blanks by means of a lacquer color, and drying the same bone-dry at air temperature, whereby the stacked sheets do not adhere and are suitable for use with automatic wrapping machines.

2. The method of making printed blanks or wrappers from a continuous web of lustrous, grease-proof cellulose paper, which includes so printing the web as to form a border around the blanks, the printing being done with lacquer color, drying the printed web bone-dry, and finally transversely cutting the web in the printed borders to form transverse bleed borders.

3. The method of' making printed blanks or wrappers from a continuous web of lustrous, grease-proof cellulose paper, which includes so printing the web as to form not only desired printed matter, but also a border around the blanks, the printing being done with lacquer color, drying the printed web bone-dry at ordinary temperature, and thereafter cutting the web in the printed borders to make bleed borders while forming the desired blanks.

4. An uncoated blank or wrapper'of regenerated cellulose sheeting having printed thereon a border of a lacquer ink.

5. An uncoated blank or wrapper of regenerated cellulose sheeting having printed thereon a border of an ink which when dry resists sticking to another wrapper when said wrappers are stacked together under unfavorable atmospheric conditions.

6; A` stack of uncoated blanks or wrappers of regenerated cellulose sheeting, each of said wrappers having printedl thereon a border of a lacquer ink.

'.1. Thev method of preventing a stack of blanks or wrappers made of regenerated` cellulose sheeting from sticking together, which comprises printing on said wrappers a border of a lacquer ink.

8. The method of making printed blanks or wrappers from cellulose sheeting, which comprises printing a continuous web of said sheeting with a plurality of border-forming units of an ink which will not adhere to a similar body of ink when dry, drying the ink, cutting said web into a plurality of individual sheets provided with a border, and stacking said sheets together.

IRVING GURWICK.

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