CA1041817A

CA1041817A - Method for making a tearing edge construction

Info

Publication number: CA1041817A
Application number: CA240,297A
Authority: CA
Inventors: Joseph W. Feeney
Original assignee: International Paper Co
Current assignee: International Paper Co
Priority date: 1975-11-24
Filing date: 1975-11-24
Publication date: 1978-11-07
Also published as: NZ182698A; NL7612861A; GB1528040A; LU76255A1; FR2332218A1; AU507896B2; DE2559292A1; AU1990276A; BE848657A

Abstract

METHOD OF MAKING A
TEARING EDGE CONSTRUCTION

ABSTRACT OF THE DISCLOSURE

A method of making a tearing edge formed of paper-board and integral with a dispensing carton from which lengths of a sheet material contained therein, such as aluminum foil, plastic wrap, and waxed paper, are dispensed. The method includes cutting a serrated line in a piece of paperboard material to form two portions, each having a serrated edge, so that the teeth of one portion mesh with the valleys between the teeth of the other portion; spraying a tooth hardening material under pressure against one outer surface of the paperboard approximate the serrated edges; folding the portions against each other along fold line segments which integrally connect the portions together at the ends of the serrated edges, so that each tooth of one portion is positioned between two teeth of the other portion; and securing the portions together.

Description

.~ BACKGROUND OF THE INVENTION
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, This invention relates to a method for making a tearing edge, especially for use with consumer packages of aluminum foil, clear plastic wrap, waxed paper and the like.
More particularly it concerns a method for making an improved tearing edge construction, formed from a carton blank and as an integral part of a dispensing package for containing a roll of such material for easy dispensing in desired lengths.
Typical dispensing packages for sheet materials of -~
this type are formed from paperboard and have a metal or ;~ plastic serrated tearing edge attached to a front or bottom edge to assist in dispensing desired lengths of material.
These edges are expensive and somewhat dangerous, since, when -~
handling the package,the user can easily injure his fingers . , due to the sharpness of the edge. In addition, the edges tend to damage other packages on store shelving and scratch furniture on which they are placed. Further, manufacture of ~ the package is more cumbersome and difficult when a separate -~ tearing edge device is attached to it.
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Previous attempts to provide a serrated tearing edge made from paperboard have not been successful. One reason for ~ this lies in the fact that heretofore, no one has designed a : :
paperboard tearing edge which works effectively and for the -, required number of times without wearing out.
It i~ therefore one object of this invention to provide a method for making an improved-tearing edge construc-tlon for severing sheets of material from a roll or other , , supply of such material. -~
Another object is to provide a method for making this , 30 tearing edge construction as an integral part of a dispensing package for containing such material.

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1(~ 7 Further, other and additional objects of this invention wi11 become apparent from the summary and description of the invention hereinafter taken in connection with the accompanying drawings and the appended claims.
SUMMARY OF THE INVENTION
- ~ accordance with the present invention, a method of making a tearing edge construction, for severing lengths of wrapping material and the like from a supply of such material, is provided comprising the steps of cutting a serrated line in a piece of paperboard material to form first and second portions, each of the portions having a line of teeth between its ends defining a serrated edge and the portions being integrally connected with each other along fold line segments at opposite ends of the serrated edges, so that the teeth of one of the portions mesh with the valleys between the teeth of the other of the portions;
spraying a tooth hardening material against a selected outer surface of the piece of paperboard material approximate the serrated edges under sufficient pressure to cause the material ¦-to penetrate substantially the entire thickness of the paperboard ¦-without appreciably staining its opposite surface; folding one ; of the portions along the fold line segments against the other ` of the portions, so that each tooth of one portion is positioned between two teeth of the other portion; and securing the portions together. In practice, a spraying pressure from about 600 p.s.i.g. -to about 800 p.s.i.g. is required for satisfactory results. -Futher, the paperboard material in which the serrated cut line is made may comprise a carton blank having bottom, rear, top, bottom front, and top front panels and a flap integrally -connected with a selected one of the bottom front, bottom, and top front panels, where the first portion . ~ -,,,' - "-,, '~
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comprises an edge of either the bottom front, hottom, or top front panel and the second portion comprises the flap.

BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a three dimensional view in partial section illustrating a tear edge construction which may be made by the method of the present invention.
Figure 2 is a plan view showing a paperboard carton blank in which a serrated line is cut between the added flap and the bottom front panel of the blank in accordance with the method of the present invention.
Figure 3 is a plan view of a second carton blank similar to that in Fig. 2, but in which the serrated line is . cut between the added flap and the top front panel of the blank in accordance with the method of the present invention.
~3' Figure 4 is a plan view of a third carton blank~ similar to that of Fig. 2 but in which the serrated line cut ,~ is made between the added flap and the bottom panel in accord-ance with the method of the present invention; the added flap being supplied between the bottom panel and the bottom front panel of the blank.
Figure 5 is a profile in cross-section view through the middle of the carton blank of Fig. 2 when it is erected, whereby the added flap is folded and secured on the inner surface of the bottom front panel. -Figure 6 is a view similar to Fig. 5 but of the carton blank of Fig. 3 when it is erected. -Figure 7 is a view similar to Fig. 5, but of the :, . . :. .
ij carton blank of Fig. 4 when it is erected. -Figure 8 is a three dimensional view showing a tear ~, 30 edge con~truction made by the method of the present invention , . .

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,, - , , , ,~ ", . , , , ~ , : , and embodied in the erected carton of Fig. 2. ~he carton is shown partially in section with the tear edge formed at the upper edge of the bottom front panel and a sheet which is partially severed by the edge is also shown.
Figure 9 is a view similar to Fig. 8 in which the tear edge construction is embodied in the erected carton of Fig. 3. The carton is partly broken away showing the tear edge on the bottom edge of the top front panel.
Figure 10 is a view similar to Fig. 8 in which the tear edge construction is embodied in the erected carton of Fig. 4, where the tear edge is formed at the front edge of -~ the bottom panel.

DESCRIPTION OF THE
PREFERRED EMBODIMENTS
, The paperboard material from which the tearing edge construction is made preferably is a commercially avail- ~ -able, solid, bleached sulfate paperboard, clay coated on one side,having a thickness from about .016 inch to about .022 inch. -Paperboard such as this i~ available from the Tnternational Paper Company under the trademark ~Val-U-Coat". However, any .t other paperboard material of an appropriate thickness may be i utilized, provided its liquid adsorption characteri~tics enable ; it to be substantially penetrated throughout its entire thickness by the hardening material selected upon spraying this material under a suitable pres~ure against a selected outer surface of the paperboard material, without appreciable staining of the opposite ~ surface of the material.
;~ Once the paperboard material is selected, a serrated ~-i: cut line i8 die cut in a piece of the material to form first and second portions, each portion havlng a line of ~eeth between it~ end~ defining a serrated edge. ~lthough the drawing~ will be di~cu8~ed in detail below, Pig~ 2-4 indicate generally at 46 ~ -, , , ... .
5.
,, the serrated cut line which forms the serrated edges. The portions are integrally connected with each other along fold line segm~nts, generally indicated as 24 in Figs. 2-4, at opposite ends of the serrated edges, so that the teeth of one of the portions mesh with the valleys between the teeth of the other of the portions.
Preferably each edge has about 4 to about 5 teeth per inch. Also, the serrated cut line forming the teeth is non-continuous. The cutting die may be "nicked" so that 10 ~ections of uncut material remain along the serrated cut line.
Preferably these uncut sections are formed midway between the peaks of selected teeth along the cut line and when so formed they act as hinge members connecting the teeth of one serrated edge with the teeth of the other serrated edge. One advantage -~
of this step i8 that both serrated èdges are maintained in a ''~',f' single plane while the paperboard carton is moving th~ough a conventional folding and gluing apparatus. The uncut material along these edges prevents the teeth from rising out of this plane where it can jam the equipment and become damaged. Another ad-~; 20 vantage of this step is that it facilitates better tooth forma-~ tion and impregnation. Conventionall~, cutting dies for forming -~ serrated edges have been nicked at selected opposite peaks to keep the teeth in a single plane. This resulted in uncut --~
` material at selected tooth peaks. This material would tear and i split the peak of the affected teeth when the material was J foldea along a line midway between the peaks of the serrated cut line. By placing the die nicks at the locations suggested in the ~ tooth forming step of this invention, ~his difficulty is avoided ;~ and the completed cut line at the peaks of every tooth facilitates 30 instead of hinder~, the impregnation of the peaks of every tooth ~ith hardening material. It is understood that the ,, .

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number of sections of uncut material and the pattern of these uncut sections may be varied in accordance with the require-ments of the tearing edge construction being manufactured.
After the die cuts the serrated cut line in the paperboard material, a selected tooth hardening material is sprayed against the non-clay coated surface of the paperboard material from a spray gun. The tooth hardening material may be selected from materials including, but not limited to, polyurethane lacquer, nitrocellulose, or silicone, which are 10 dissolved in a solvent such as acetone, ethyl acetate, or methyl ethyl ketone. Preferably the material is a polyurethane lacquer manufactured by Polymer Industries under the trademark Mira-Glos RT 101A/101C. Preferably it is dissolved in acetone to have a vi~cosity from about 18 to about 21 seconds as measured in a No. 2 Zahn cup, but other solvents such as those mentioned above t may be also utilized to bring the material to a satisfactory vis---l cosity. The solvent selected should not dry so fast that the -~ hardening material does not completely penetrate the paperboard.
! The amount of tooth hardening material applied to the 20 paperboard material should be sufficient to penetrate substan-` tially the entire thickness of the paperboard material without - - -appreciably staining the board's opposite surface. Some of the --factors which have been found to be important in the effective impregnation of the teeth of the serrated edges with a hardening ~ --material include the pressure under which the material is sprayed, --~
the veloc~ty of the ~pray, the distance of the spray gun from the paperboard material, the pattern of the spray applied against the paperboard material and the speed of movement of the paperboard ~ relative to the spray. The following ranges for these factors -; 30 have been fGund to be mo~t useful when polyurethane dissolved in acetone ~8 the selected hardening material, however they may vary ~-out~ide the ~imit~ ~pecified if other materials are utilized.
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lt~1~7 This hardening material is preferably sprayed against the paperboard through a nozzle at pressures from between about 600 p.s.i.g. to about 800 p.s.i.g. In cases where the tearing edge construction being made is not required to have completely hardened teeth, the pressure may be less, but depending on the viscosity of the material, the distance of the nozzle from the paperboard and the size of the opening in the nozzle, the penetration of the paperboard material will be less complete when the pressure is below 600 p.s.i.g. At pressures over 800 p.s.i.g., penetration is --complete, but the spray is more difficult to control.
Depending upon the particular values chosen for the factors mentioned above, when the pressure of the spray being -~ -applied is between 600 p.s.i.g. and 800 p.s.i.g., it has been found that a satisfactory spray velocity is achieved using a :.
nozzle which delivers .04 gallons/minute of water under a ~i pressure of 500 p.s.i.g.
X~ The spray gun is preferably placed from between ~;; about .25 inches to about .75 inches from the paperboard material for teeth of the size illustrated. For larger or smaller teeth in the serrated edges and variations in the other factors mentioned above, this distance may be larger or smaller as long as the pattern of material sprayed against the paperboard material covers at least the entire tooth area between the peaks of the serrated cut line. Preferably, when the nozzle i8 between .25 inches and .75 inches away from the paperboard the spray pattern has a width of from about .25 inches to about .75 inches when it reaches the paperboard.
Generally, in the preferred method of making the tearing edge con~truction, the paperboard material as a flat -~

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ll~ 7 sheet moves on a conveyor beneath the spray gun, thus the tooth hardening material is applied as a uniform coat against the teeth. It has been found that under the conditions men-tioned above, the paperboard material can be moved beneath the nozzle at speeds as high as 10,000 ft. per hour to about 20,000 ft. per hour with satisfactory penetration of the hardening material.
It is contemplated that when a value for a factor mentioned above, such as viscosity of the tooth hardening material, is outside the range given above, that the value of -~
another factor, such as pressure under which spray is applied, may be modified so that the amount of hardening material ~ applied remains constant. ,~
: After the paperboard material has been cut and the tooth hardening material applied, the paperboard is folded along the uncut fold line segments at the opposite ends of the serrated edges to form the tear edge construction, in which each tooth of the first serrated edge is positioned between ~
: two teeth of the second serrated edge. This double layer tear -: . ,-:
~ 20 edge construction is best shown in Fig. 1. The two portions -~s .~
of the paperboard material are then secured together by the application of any one of several known glues or adhesive -agents. Preferably, they are secured together along the serrated edges.
~ Referring now to Figure 1 of the drawings, a tearing ----~ edge made according to the method of this invention is shown which comprises a first portion 12 of paperboard having a line ` ~
~- of teeth 14 defining a first serrated edge 16 and a second --portion of paperboard 18 having a line of teeth 20 defining a second serrated edge 22. These two portions are folded over 9- ..
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' about two fold line segments 24 at opposite ends of the portions and are securely held in this position by some adhe~ive material 26. In addition, the teeth have been spray impregnated with polyurethane 28 to harden them for better cutting efficiency and longer life.
Manufacture of a dispensing carton having the tear edge construction described above can be most advantageously achieved using a method described above because the tearing edge and the carton blank could be formed integrally together from a single piece of material. When cutting out a carton blank, for example, in addition to providing it with bottom . ~. , - .
~, front, bottom, rear, top and top front panels separated from each other by fold line~, the tearing edge can be obtained by . i .
' providing an additional length of material connected to one or ; . .
more of the panels by suitable fold line~ or fold line segments.
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By die cutting the paperboard material as described above along the fold line between this additional length of material or ,~ flap and the panel to which it is attached, the serrated edges '`~'A~ which will eventually form the tearing edge are made.
~i 20 For example, a dispensing carton having an integral 4 tearing edge construction can be made in accordance with the present invention by first selecting a piece of paperboard material from the carton blanks illustrated in Figs. 2-7.
Referring now to Fig. 2, the carton blank 44 illus-~j trated has bottom, rear, top and top front panels 36, 38, 40 $- and 42, as well as bottom front panel 32 and a flap 34 attached to the panel along fold line segments 24a. A~ can easily be seen, a single serrated line 46 may be cut through the blank 44 between ths fold line segments 24a. In addition, the top front panel 42 is divided into two portions 42' and 42" with a cut .

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l~J4~ 7 score line 47 along their length separating these two portions.
Referring to Fig. 3, the blank 48 has the usual bottom front, bottom, rear, top and top front panels 32a, 36a, 38a, 40a and 42a, respectively, as well as a flap S0 connected along fold line segments 24b to the top front panel 42a. Here as in the case of the previous blank 44, a single serrated line 46a may be cut through the blank 48 between the fold line segments 24b. In addition, the bottom front panel 32a is divided into two portions 32a' and 32a" which are separated by a fold line 33 along their length.
Referring now to Fig. 4, the blank 52 has bottom front, bottom, rear, top and top front panels 32b, 36b, 38b, 40b and 42b, respectively. Between the bottom and bottom front panels 36b, 32b there is a flap 54 added which is connected -~ along its length by a fold line 56 to the bottom front panel " ,.
32b along fold line segments 24c. Between the fold line seg-' ments a serrated cut line 46b may be made. In addition, the flap 54 is provided with a fold line 58 parallel to but spaced from the fold line 56. The purpose of this second fold line ~ ~is to bring the paperboard back out to the front of the carton -before extending the panel 32b upwardly as seen in Fig. 10. -After the selected carton blank has been formed, the , . . .
~ tooth hardening material has been sprayed against the serrated ~-.~ edges, and the portions having the lines of teeth have been folded and glued together, then the blank is folded into a flat form in which it is easily shipped to the customer. Referring ~ to Figure 5, in blank 44 the bottom front panel flap 34 is '~ folded over and adhesively secured to the inner surface of the bottom front panel 32 along the fold line segments 24a (not j~ 30 shown). Then the blank is folded along a fold line 60 between i:~
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f 1(:3~i~17 the bottom and rear panels 36, 38 and the top front panel 42"
adhesively secured to the bottom front panel 32 at one or more desired locations below the cutting edge lOa. The cut score line 47 will break on opening the carton.
Referring to Figure 6, the top front panel flap 50 is preferably folded under and secured to the inner surface of the top front panel 42 to form the tearing edge lOb. The blank is also folded along the fold line 60a and the upper end portion 32a" of the bottom front panel is folded over and along line 33 and adhesively secured to the inner surface of the top front panel. The flap 50 is lightly adhesively secured to the portion 32a' of the front panel 32a at several points along -its length. This adhesion is easily broken in a conventional manner to open the carton after it is erected and filled.
Referring to Fig~ 7, the blank 52 is folded along the ~
~~ fold line 60b and the top front panel 42b is temporarily ~ --~ adhesively secured to the bottom front panel 34b for ease in opening the carton. With regard to this carton, the cutting ~ - --edge lOc is exposed during its shipment in flat form. Forma~
tion of the cutting edge is accomplished by folding the flap 54 -~ along fold line segments 24c (not shown) onto the inner surface .~, of the bottom panel 36b. There, the portion of the flap between ~' the fold line 58b and the fold line segments 24c is adhesively secured to the panel while the portion between the fold line 56 i- and the fold line 58 is folded back on itself until it reaches the bottom front panel 32b of the front of the carton. A fold is then made along the fold line 56 to position the bottom front panel to form the front of the carton.
~, As seen in Fig. 8, the tearing edge lOa forms an ; 30 integral part of paperboard carton 30. ~hus the first portion ,~, 12.

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of 12a of the carton comprises the bottom front panel 32 and the second portion 18a comprises a flap 34 which is - ntegrally connected with the panel at the fold line segments 24a (not shown). The carton also includes bottom, rear, top and front panels 36, 38, 40 and 42, respectively, as well as their normally associated flaps to complete the carton and enclose the material to be dispensed. The carton includes the adhesive 26a and the hardening coating 28a as well. The sheet material 29 to be severed is urged downwardly against the cutting edge lOa. -Referring now to Figures 9 and 10, a portion of each of the cartons erected from the blanks of Figs. 3 and 4 are ; shown. The carton of Fig. 9 has the tear edge construction lOb forming an integral part of its top front panel 42a and is ~ ~
illustrated with a portion of sheet material 29 being torn off ~ -upwardly against the edge. The carton of Fig. 10 has the tear edge construction lOc forming an integral part of its bottom :-panel 36b and is illustrated with a portion of sheet material 29 being torn off rearwardly against the edge.
In two of the cartons described above made according to the method of this invention, a flap is added integral with - -one of the two front panels and is connected to its adjacent panel along fold line segments at opposite ends of the flap.
In these cartons a single serrated line is cut through the mate- -rial severing the flap from the adjacent panel along the serration between the fold line segments. Thereafter, the flap is prefer-'~A ably folded over along the fold line segments so it lies adjacent the inside surface of the panel forming two adjacent rows of 'l~ teeth, one on the flap, the other on the panel. It could also ~, . , 30 be folded into the outside surface of the panel, but would not ,- ', .

1~14 1~1~7 be as attractive if done that way. Either way, the teeth in each row are staggered between the teeth of the other row.
This has the effect of doubling the number of teeth and since it allows each tooth to be larger increases the strength of the cutting edge. In addition each tooth lies adjacent to and helps support two teeth in the adjacent row.
In order to make sure that the teeth in both rows of the cutting edge lie at the same elevation with respect to the fold line segments, the serrated cut in the material is made so that a line through the middle of the cutting die -~
passes through the points on the carton which include the . fold line segments. Naturally, if it is desired to elevate one line of teeth with respect to the other, the fold line i segments can be placed closer to the peaks of one set of - -. teeth than the other to accomplish this.
Other modifications in the methods described above may be made without deviating from the present invention.
It is desirable in any dispensing carton to have ~ -the cutting device 10 come close to the ends of the carton in - -order that the sheet material to be cut not be significantly wider than the cutting device 10 itself. Accordingly, the fold line segments integrally connecting the two stiff sheet ~ material portions of the device together are preferably small ; as compared to the length of the device itself. Normally to facilitate dispensing the paper or other material in the carton the width of the paper will be somewhat less than the interior ,~ dimension of the carton. This leeway is a measure of the ~ preferred length of the fold line segments. ~ ~
'-~ In describing this invention, to facilitate under- -~ 30 ~tanding, the letters a, b and c have been used with one ~: .

, . , lU41~1'7 reference numeral or another to indicate the same part of the blank or carton in each of the embodiments. Thus the tear edge construction per se has been given reference numeral 10 which in the preferred, second and third embodiments of the carton according to the invention the edge has been given reference numerals lOa, lOb and lOc, respectively.
Further, other and additional modifications of the invention, such, for example, as connecting the serrated edges integrally together along a fold line at the bottom of their respective portions, will occur to those skilled in the art and are intended to be within the scope and spirit of the invention.

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Claims

The embodiments of the invention in which-an exclusive property or privilege is claimed are defined as follows:-

1. A method of making a tearing edge construction, for severing lengths of wrapping material and the like from a supply of such material, comprising the steps of cutting a serrated line in a piece of paperboard material to form first and second portions, each of said portions having a line of teeth between its ends defining a serrated edge and said portions being integrally connected with each other along fold line segments at opposite ends of said serrated edges, so that the teeth of one of said portions mesh with the valleys between the teeth of the other of said portions;
spraying a tooth hardening material against a selected outer surface of said piece of paperboard material approximate said serrated edges at a pressure from about 600 p.s.i.g. to about 800 p.s.i.g. to cause said tooth hardening material to penetrate substantially the entire thickness of said paperboard material without appreciably staining its opposite outer surface;
folding one of said portions along said fold line segments against the other of said portions, so that each tooth of one portion is positioned between two teeth of the other portion;
and securing said portions together.

2. A method according to claim 1 wherein said hardening material is selected from the group consisting of polyurethane, silicone, and nitrocellulose.

3. A method according to Claim 2 wherein said hardening material is a polyurethane dissolved in acetone.

4. A method according to Claim 1 wherein said securing step comprises securing said portions together along said serrated edges by an adhesive.

5. A method according to Claim 1 wherein said piece of paperboard material in which said portions are formed comprises a carton blank having bottom, rear, top, bottom front, and top front panels and a flap integrally connected with a selected one of said bottom front, bottom, and top front panels, said first portion being formed in a selected one of said bottom front, bottom, and top front panels and said second portion being formed in said flap.

6. A method according to Claim 5 wherein said first portion is formed in said bottom front panel.

7. A method according to Claim 5 wherein said first portion is formed in said top front panel.

8. A method according to Claim 5 wherein said first portion is formed in said bottom panel.

9. A method according to Claim 1 wherein said serrated cut line is non-continuous, so that there is at least one uncut section of said paperboard material along said cut line between the peak of at least one tooth of one of said edges and the peak of at least one tooth of the other of said edges, said section being located about midway between said peaks.

10. A method according to Claim 1 wherein from about 4 to about 5 teeth per inch are cut in each of said serrated edges.

11. A method according to claim 1 wherein said hardening material is sprayed against said paperboard material from about .25 inch to about .75 inch above said material.

12. A method according to claim 1 wherein said hardening material is sprayed against said paperboard material while said material is moving at a speed from about 10,000 feet per hour to about 20,000 feet per hour in relation to said spray.

13. A method according to claim 1 wherein the pattern of said hardening material being sprayed against said paperboard material covers at least the entire tooth area between the peaks of the serrated cut line.

14. A method according to claim 13 wherein said pattern has a width from about .25 inch to about .75 inch inch when it reaches said paperboard material.

15. A method according to claim 1 wherein said paper-board material is a solid bleached sulfate paperboard, clay coated on one side, and has a thickness from about .016 inch to about .022 inch, said tooth hardening material is a polyurethane dissolved in acetone, said hardening material is sprayed against said paperboard material from a distance between about .25 inch to about .75 inch above said paperboard material while said paperboard material is moving at a speed from about 10,000 feet per hour to about 20,000 feet per hour in relation to said spray, the pattern of said spray covering at least the entire tooth area between the peaks of said serrated cut line, and said portions are secured together along said serrated edges by an adhesive.