US3001644A

US3001644A - Cellulosic product

Info

Publication number: US3001644A
Application number: US843686A
Authority: US
Inventors: Charles A Fourness; Jr Cephas B Sitterson
Original assignee: Kimberly Clark Corp
Current assignee: Kimberly Clark Corp
Priority date: 1959-10-01
Filing date: 1959-10-01
Publication date: 1961-09-26
Anticipated expiration: 1978-09-26

Description

p 1961 c. A. FOURNESS ETAL 3,001,644

CELLULOSIC PRODUCT Filed Oct. 1, 1959 2 Sheets-Sheet 1 Sept. '26, 1961' c. A. FOURNESS EIAL 3,001,644

CELLULOSIC PRODUCT 2 Sheets-Sheet 2 Filed Oct. 1, 1959 United States Patent 3,001,644 CELLULOSIC PRODUCT Charles A. Fourness and Cephas B. Sitterson, Jr., Appleton, Wis., assignors to Kimberly-Clark Corporation, Neenah, Wis, a corporation of Delaware Filed Oct. 1, 1959, Ser. No. 843,686 7 laims. (Cl. 20656) This invention relates to improvements in the individual packaging of articles such as paper products or the like which may advantageously be maintained compressed or partially compacted for reduction or" bulk thereof.

A primary object is to provide a low cost dimensionally stable hermetically sealed package capable of being stacked and which is easily removed from its compressed or compacted contents without the necessity of providing means such as lines of fracture, tear strings or the like to insure a desired tear path for easy opening or complete removal of the package from its contents.

Another object is to provide a heat sealed enclosure of improved sheet material about light weight partially compacted contents which determines the contour of the resulting package while maintaining the sheet material under tension in a manner to be easily torn in the direction of a desired tear path encircling the item for removal of the enclosure material.

A still further object is to employ an improved plastic film product having directional strength and tear characteristics in a manner to provide a protective sealedenclosure for a pmially compressed and expansible article while best utilizing those characteristics in providing a desired tear path without resort to lines of weakening, tear strings, or path directing devices.

Other objects are generally to improve and simplify the packaging of one or a plurality of light weight compactable articles maintained compacted within the elastic limits thereof while packaged.

In the drawings:

FIG. 1 shows a packet of envelopes enclosed in a wrapper incorporating the invention;

FIG. 2 illustrates a clip or stack of facial tissues packaged in accordance with the invention;

FIG. 3 illustrates a pocket pack of facial tissues packaged in the manner taught herein; FIG. 4 illustrates a double roll of hand towels enclosed in a package incorporating the invention, with parts broken away to illustrate the degree of compaction of the towels;

FIG. 5 diagrammatically illustrates the application of the improved wrapper material to a double roll of hand towels during a wrapping step resulting in compaction of the toweling stock; and

FIG. 6 shows in perspective and greatly enlarged a fragment of the wrapper material with which articles are packaged in the manner taught herein.

, While it is known to employ plastic film for the hermetically sealed enclosure of various articles, the physical characteristics thereof such as stretch, tensile strength and heat scalability have imposed severe limitations on the use of very thin sheets of polyethylene or similar high polymer plastic materials for the enclosure of compacted articles which require constraining forces. It is also generally known to employ paper as a backing for polyethylene or similar plastic films to strengthen the film for pack-aging use. The packaging of articles in such material may be done on known automatic machines. The invention is concerned with the solution of certain problems which have limited the use of very light weight polyethylene and similar sheet stock for the packaging of light weight articles which advantageously are maintained partially compacted for bulk reduction. A very 3,53%1544 Patented Sept. 26, 1961 "ice soft and pliable web-backed polyethylene laminate is employed to package articles in accordance with the invention in a manner to insure easy partial or complete removal of the package forming material from its contents in the absence of known aids such as tear strings, tabs, and lines of fracture as tear path directing means and with attendant substantial savings in package fabrication.

During production by extrusion of certain types of plastic film, such as polyethylene film, the film is subjected to sufficient stretch to efiect molecular alignment in the machine direction with the result that the film has greater tensile strength in that direction than in the cross direction. While not all plastic materials may be thus stretch strengthened, the invention is related to plastic materials which possess such molecular characteristics and is particularly directed to thin films of polyethylene which have been produced under conditions which impart a machine directional strength in excess of the cross directional strength by about 10% to 60%. It is also well known that most light weight paper produced on a Fourdrinicr paper machine has machine directional strength in excess of its cross directional strength, the particular conditions of manufacture governing the ratio therebetween.

Thin sheets of certain plastic materials such as polyethylene are thus characterized by a grain direction, as is most light weight paper. Since in both materials cross directional bonds are weaker than machine directional bonds, the path of minimum tear resistance is aligned with the direction of greatest tensile strength, which is the machine direction.

These physical characteristics have heretofore been recognized in the packaging art and to some extent have been utilized in establishing desired tear paths. While relatively thick polyethylene film exhibits sufficient directionality of tear characteristics to be torn in the grain direction when serving as an article enclosure, very thin films, for example, of a thickness of one mil or less, do not under like conditions exhibit very strong tear characteristics due to film weight even though such film may be somewhat stronger in one direction than in the other. However, when a very thin film of polyethylene or the like is bonded to a light weight fibrous web with the grain direction of each in alignment, an additive effect is obtained with the resulting laminate product having the combined directional tear characteristics of both the film and web. The plastic film product employed in packaging articles in accordance with the invention is fabricated in a manner to utilize the combined directional tear characteristics of a light weight creped web of cellulosic fibers and a very thin film of polyethylene or similar high polymer plastic. V

Laminated sheet material as below described insures complete conformability of the wrapper material to those surfaces of the packaged contents which define the contour of the package. The present invention is directed to the concept of so applying an improved plastic film laminate to a compacted article that the grain direction of the laminate is oriented to encircle the compacted article in that direction requiring maximum constraining forces. Orientation of the laminate in such manner permits use of a laminate of both minimum web and film Weight while eliminating the necessity of providing either lines of perforation or special devices such as tear strings or tapes to define an article-encirclin tear strip for removal of the laminate from the enclosed contents.

It is important that the film laminate employed in accordance with the invention forthe packaging of compacted articles exhibit some inherent elasticity to insure a desired uniformly smooth contour throughout the surface of the package. It is also important that the amount of inherent elasticity be maintained within controlled limits and that the film laminate be capable of maintaining its elasticity during the reasonable shelf and use life of an article so packaged. The film product herein employed for packaging is soft and pliable and presents a very pleasing appearance.

Neat and attractive packaging of compactable light weight articles such as facial tissue, envelopes and fiuify hand towelling is both simplified and improved by the invention. While it is known to use non-reinforced polyethylene film of several mils thickness for packaging purposes, such film is not entirely satisfactory for many such usm. When compacted articles are packaged with such film under a degree of compaction sufiicient to reduce the bulk to an extent often desired, the film has a tendency to grow and the film material to loosen and present a saggy appearance. While polyethylene and similar films are sometimes backed with kraft or other non-creped paper, such a product lacks appreciable stretchability, hence it is difficult to obtain smooth conformability to the contour of the enclosed article. For example, when known types of paper-backed polyethylene film are employed to form an hermetically sealed package about light weight compactable paper in roll form, the laminate is usually maintained taut throughout that portion encircling the roll, but the portions overlapped and sealed at the roll ends, since not subjected to the same forces of expansion as the roll encircling portion, frequently present a loose and sloppy appearance. I

The plastic film material comprising the packages illustrated in the drawings consists of a fibrous creped web of a basis weight of about 6 to 14 pounds per ream per 3000 square feet, having bonded on one sidethereof a film of polyethylene or the like of a thickness in the range of about .35 to 2.5 mils, with the bonding confined to the crests of the web. The crepe ratio is maintained within limits of about 1.5 to 3. During fabrication the web and are properly aligned to obtain the added efiect of their maximum tensile strength and tear resistance characteristics. Such material, within the Weight and thickness ranges above defined, is easily torn in the direction of its maximum tensile strength and especially when maintained under slight tension the tear will closely follow that direction. While the tear line may depart somewhat from a true linear path, it nevertheless will not appreciably depart therefrom. Polyethylene of a thick.- n'ess between about .35 and 2.5 milsis extruded in a manner to insure molecular orientation resulting in machine directional tensile strength in excess of cross directional strength by at least 20% to 30%. Such a film exhibits about 15% to 20% more cross directional than machine directional tear resistance.

Mo light Weight mi ed fa issue waddins at b sis weights between 6 and 14 pounds per ream exhibits a ratio of cross directional to machine directional strength somewhat less than 2 to 1. The plastic film Product taught herein comprises creped wadding fabricated in a manner to insure that its machine directional strength exceeds by at least 2.5 to 1 its cross directional strength. Wadding 12 of the above characteristics, weights and crepe ratios, has bonded to one side thereof a plastic film 14 ofthe abOve thickness range and directional tear characteristics. The added effect of such directional characteristics results in the product having very high machine directional strength in comparison to its cross directional strength. The cross directional tear resistance exceeds machine direction tear resistance by a factor of at least 35 FIG. 6 illustrates a fragment of a plastic film sheet material 10 comprising a creped web 12 of cellulose fibers having thermally bonded to the top surface, as shown, a thin film of polyethylene 14. Arrow 16 indicates the machine direction of both the plastic material and the web which are in alignment as above mentioned, the method of producing such a product being known.

FIGS. 1 through 5 illustrate various light weight paper products packaged with the material of FIG. 6, arrow 16 indicating the direction of minimum tear resistance above mentioned. The plastic product is applied in each instance to the lightweight contents in a manner partially to compact and retain the contents in compacted form. Most items so packaged require a somewhat greater restraining force in one direction of encirclement than in a direction opposite thereto. Plastic product 10 is applied about the article with the machine direction of the material aligned with the direction of encirclement which requires the greater restraining forces. It is important that the plastic product be maintained taut by the partially compacted contents to insure proper tear along its machine direction.

Certain products to be packaged will exert substantially equal forces in either direction of encirclement of the product, as for example the envelopes 18 of FIG. 1. Plastic film product v1 0 may be fabricated into package form by known folding and sealing apparatus with its machine direction indicated by arrow 16. To provide a centrally disposed tear path as shown, an integral tear tab of the type shown at 22, FIG. 2, is provided at the lower margin of 'the overlapped side wall portion 20. The width of tab 22 controls the width of the resulting tear path shown defined marginally at 25 and 26, FIG. 1 and shown dotted at 24, FIG. 2. FIG. 2 illustrates a stack or clip of facial tissues shown non-compacted at 30 but also shown substantially compacted and completely enclosed by package 32 incorporating the invention.

The details of Package construction are relatively unimportant so long as they incorporate the concept of em: ploying the directional characteristics of the plastic film product in a manner to permit the use of a product of minimum weight while insuring proper tearing during complete or partial opening of the package. In each instance, however, the plastic film product 10 is formed about the packaged contents under sufficient tension substantially to compact the contents and is heat sealed along the side and end flaps except in the area thereof forming the integral tab portion 22, FIG. 2. While the tab end must be easily available to a user, it is immaterial whether the tab is formed integrally with the plastic film product or is suitably bonded thereto. A preferred tab maybe formed by leaving an unbonded oval-like portion defined by the lower tab margin and an upper margin shown dotted at 34, FIG. 2.

FIG. 3 illustrates the invention incorporated in a small package of facial tissues termed a pocket pack. The plastic film product is applied over the packaged stack of tissues 36 and a cardboard stiffening base 38 with the machine direction 16 of the film product thereof Oriented in the direction of maximum package length. All overlapped'end flap 40 is provided with a tear tab 22 similar to its counterpart shown in FIG. 2 with the intended tear path shown dotted at 42 but prior to tear and at 4'4 after being torn. In this instance it is desirable to provide a tear path extending from one end to the other without completely encircling the package and without destruction thereof to permit the tissues to be individually extracted through the slot thus formed in the top of the p age- FIG. 4' illustrates the invention incorporated' in a package 46 enclosing and retaining two

rolls

48 and 50 of light weight hand towelling or the like in substantially compacted form. Since maximum retention forces are required in the direction of encirclement indicated by arrow 16 the product is applied with its machine direction so oriented. Tear tab 20 is similar'to those above described to permit either partial or complete severance of the packaging material, depending on whether one or two rolls are to be removed therefrom. Severance of the wrapper material through an arc encircling only the top half of'the package 46 permits removal of the top roll and folding over of the plastic product for enclosure of the bottom roll as a protective covering.

.FIG. illustrates the manner in which the two rolls of

towelling

48 and 50 may be enclosed while under compaction in the plastic film product above described. The manner in which the package is completed and sealed is not shown or described since the steps are well known and form no part of the present invention.

Further objects and advantages of the concept herein taught will become readily apparent to persons skilled in the art, the scope of the invention being clearly defined in the appended claims.

We claim:

1. In combination, a light weight compactable article and a package formed of a plastic film product maintaining said article partially compacted, said plastic film product consisting of a film of polyethylene of thickness within the range of about .35 to 2.5 mils forming the outer surface of the package and a sheet of creped wadding disposed inwardly of the film and bonded at the crests thereof to the film, said wadding having a basis weight of about 6 to 14 pounds per 3000 square feet and a crepe ratio of about 1.1 to 3, the fibers forming said wadding being disposed in a manner to define a grain direction in which the tear resistance in the grain direction is less than one third the tear resistance in a direction across the grain, said product being applied to encircle said compacted article in a direction requiring maximum constraining forces, and a tear tab associated with said product and positioned to permit said product to be torn in the grain direction along a desired path for exposure of said article.

2. In combination, a light weight compactable article and an hermetically sealed enclosure maintaining said article partially compacted, said enclosure consisting of a light weight plastic film product having a direction of minimum tear resistance encircling said article in the direction requiring maximum constraining forces to maintain said article compacted, and an integral tear tab on said product positioned to permit tearing of said product in the direction of minimum tear resistance, said product comprising an outer plastic film of a thickness between about .35 and 2.5 mils and an inner backing of creped wadding of a basis weight between about 6 and 14 pounds per 3000 square feet and a crepe ratio between 1.1 and 3, with said film bonded to said wadding along the crests thereof, said wadding and film each having directions of minimum tear resistance and bonded together with such directions aligned.

3. The combination with a light weight compactable article, of a plastic film product forming an hermetically sealed package maintaining said product partially-compacted, said product comprising a film of high polymer plastic of a thickness of about .35 -to 2.5 mils having bonded to one side thereof a sheet of creped wadding of a basis weight of about 6 to 14 pounds per 3000 square feet and a crepe ratio of about 1.1 to 3 with the wadding to plastic bonds limited to the crest portions on one side of the wadding, said film and said wadding each having aligned directions of maximum tensile strength and resulting minimum tear resistance resulting in a grain direction of tear resistance, said product being applied to said article with said grain encircling the article in a direction requiring maximum constraining forces, with lateral portions of said product overlapped and thermally bonded together to complete the package, a manually accessible portion of said product forming a tear tab positioned intermediate said overlapped and sealed portions to provide means for tearing a strip of said product along said grain direction.

4. In combination, a light weight compactable article and a package formed of a plastic film product maintaining said article partially compacted, said plastic film product consisting of a sheet of creped wadding having a thin film of high polymer plastic bonded to one side thereof along the crests of the wadding, said wadding being of a basis weight of about 6 to 14 pounds per 3000 square feet with the fibers thereof oriented in a manner to insure a; machine-to-cross-di-rectional strength ratio of at least 2.5 to 1, said wadding having a crepe ratioof about 1.1 to 3, said plastic film being of a thickness within a range of about .35 to 25 mils, said resulting product being applied to said article with the film externally and the wadding internally of the resulting package, said product encircling the compacted article in a manner to so position the machine direction of the wadding to resist maximum expansion forces exerted by said compacted article and a tear tab associated with said product and positioned to permit said product to be torn in the machine direction of said wadding along a substantially linear path for exposure of said article.

5. In combination, a light weight compactable article and a package formed of a plastic film product maintaining said article partially compacted, said plastic film product consisting of a film of polyethylene of thickness within the range of about .35 to 2.5 mils forming the outer surface of the package and a sheet of creped cellulosic wadding disposed inwardly of the film and bonded along the crests thereof to the film, said wadding having a basis weight of about 6 to 14 pounds per 3000 square feet and a crepe ratio of about 1:1 to 3, the fibers forming said wadding being disposed in a manner to insure a tensile strength in excess of that in the opposite direction by a ratio of at least 2 /2 to 1, said product being applied to encircle said compacted article with the maximum tensile strength direction in the direction requiring maximum constraining forces, and a tear tab associated with said product and positioned to permit said product to be torn in the grain direction along a desired path for exposure of said article.

6. The combination with a light weight compactable article, of a plastic film product forming an hermetically sealed package maintaining said product partially compacted, said product comprising a film of high polymer plastic of a thickness of about .35 to 2.5 mils and having machine directional tensile strength exceeding cross directional tensile strength, having bonded to one side thereof a sheet of creped wadding of a basis weight of about 6 to 14 pounds per 3000 square feet and a crepe ratio of about 1.1 to 3 and a machine to cross directional tensile strength ratio of at least 2 /2 to 1, the wadding to plastic bonding being limited to the crest portions of the wadding, said film and said wadding being bonded with their directions of maximum tensile strength aligned with resulting minimum tear resistance in the machine direction of the wadding, said product being applied to said article with the machine direction of the wadding encircling the article in a direction requiring maximum constraining forces, lateral portions of said product being overlapped and thermally bonded to define package end walls, and a manually accessible portion of said product forming a tear tab positioned intermediate said end walls to provide means for tearing a strip of said product in the machine direction of the wadding.

7. In combination, a light weight compact-able article and an hermetically sealed enclosure maintaining said article partially compacted, said enclosure consisting of a light weight plastic film product having a grain direction of minimum tear resistance encircling said article in the direction requiring maximum constraining forces to maintain said article compacted, and an integral tea-r tab on said product positioned to permit tearing of said product in the grain direction, said product comprising an outer film of polyethylene of a thickness between about .35 and 2.5 mils, said film having a tear resistance in one direction less than its tear resistance in an opposite direction, and an inner backing of creped wadding of a basis weight between about 6 and 14 pounds per 3000 square feet and a crepe ratio between 1.1 and 3, said wadding having a tensile strength in one direction exceeding by at least 2% to 1 its tensile strength in the opposite direction, said film being bonded to said wadding along the crests thereof, with the direction of minimum tear resistance of said film afignegl with the direction of maximum tensile strength of sai -wagin V References Cited in the file of this patent *UNITEb STATES PATENTS 2167?,4'9'6 Myhes May 4; 1954 YQis m' Q July, 28, 19.59 Hirwmd Iu1y28, 959

v'oi tmia'ri July 28, 1959 FOREYGN PATENTS 7 Canada Q- Sebt. 6'; 1955

Claims

1. IN COMBINATION, A LIGHT WEIGHT COMPACTABLE ARTICLE AND PACKAGE FORMED OF A PLASTIC FILM PRODUCT MAINTAINING SAID ARTICLE PARTIALLY COMPACTED, SAID PLASTIC FILM PRODUCT CONSISTING OF A FILM OF POLYETHYLENE OF THICKNESS WITHIN THE RANGE OF ABOUT .35 TO 2.5 MILS FORMING THE OUTER SURFACE OF THE PACKAGE AND A SHEET OF CREPED WADDING DISPOSED INWARDLY OF THE FILM AND BONDED AT THE CRESTS THEREOF TO THE FILM, SAID WADDING HAVING A BASIS WEIGHT OF ABOUT 6 TO 14 POUNDS PER 3000 SQUARE FEET AND A CREPE RATIO OF ABOUT 1.1 TO 3, THE FIBERS FORMING SAID WADDING BEING DISPOSED IN A MANNER TO DEFINE A GRAIN DIRECTION IN WHICH THE TEAR RESISTANCE IN THE GRAIN DIRECTION IS LESS THAN ONE THIRD THE TEAR RESISTANCE IN A DIRECTION ACROSS THE GRAIN, SAID PRODUCT BEING APPLIED TO ENCIRCLE SAID COMPACTED ARTICLE IN A DIRECTION REQUIRING MAXIMUM CONSTRAINING FORCES, AND A TEAR TAB ASSOCIATED WITH SAID PRODUCT AND POSITIONED TO PERMIT SAID PRODUCT TO BE TORN IN THE GRAIN DIRECTION ALONG A DESIRED PATH FOR EXPOSURE OF SAID ARTICLE.