CA1114273A - Method of and means for making variable width zipper profile film - Google Patents

Abstract

ABSTRACT

One or more prefabricated extruded reclosable plastic profile strips travelling in the same direction and at the same speed as a prefabricated continuously travelling film web are guided into convergence with the web, transversely adjusted as to position on the web while the web and the fastener strips are travelling without interruption, and then the travelling fastener strips are permanently secured to the travelling web. The adjustability feature is especially useful to facilitate making of various sizes of bags from the zipper profile film web.

Description

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This invention relates to a new and improved method of and means for making variable width zipper profile film of the type which is especially useful in making so-called zipper bags or other articles provided with resilient, profiled reclosablc S flexible fasteners and wherein the fasteners are closed or opened by elastic deformation.
For various purposes, and especially for the manu-facture of bags, mating profiled resiliently flexible extrude(J plastic fastener strips are joined to film web which may be extrude l 10 plastic material. The fasteners may be of the type which can be joined to provide a closure by finger pressure or by means of a slider. The profiles of the fasteners are elastically deformable for this purpose. ~
Bags made from such material, which may be ~-identified as zipper profile film web, comprise thin film web walls joined along opposite sides to form a ~J shaped bag body wherein either opposite end of the bag may be initially open or openable and the remaining end closed. For example, the bottom of the bag may remain open until the bag has been filled with a contents such as merchandise and then sealed shut. On the other hand, the upper or top end of the bag may remain open or be readily openable to be filled with the contents. Separable profileclfasteners, generally along the top of the bag, permit opening and closing of the bag for access to the contents and for reclosing the bag as desired. Bags oF this general type have been widely used for z~

packaging, especially in the retail trades for purveying consumer products such as food, clothing, tools, etc. Visual inspection of the contents is facilitated by having the bag walls formed from a transparent plastic film web material.
According to prior methods of manufactu r~, the - plastic film web and fastener strips have been formed in a common extrusion operation and generally from tllc same pla stic material. This is a relatively slow process alld presents some difficulties resulting from the great difference in mass of thc film and the mass of the fastener strips at the location these are coextruded. To alleviate this difficulty, it has been proposel to prefabricate the fastener strips and the film web and then join the same either by electronic fusion or adhesively.
However, according to prior arrangements, varia-tions in the width of the zipper profile film web has required shutting down the production apparatus to effect adjustments as to width, that is, as to the positioning of the fastener strips relative to one another on the film web, and comprising changes in extrusion dies, changes in the mechanisms for bringing the fastener strips and the film web together, while the apparatus remains idle until any changes have been made . That ha s been especially wasteful procedure where only relatively short runs of the zipper profile film web of any particular widths have been needed .
Therefore, it is an important object of the present invention to overcome the disadvantages deficiencies, ineffi-ciencies, shortcomings and problems inherent in prior methods and apparatus and to provide a new and improved method of and means for making variable widths of zipper profile film accord-ing to which the width of the zipper profile film web can be expeditiously varied without interrupting continuous production.
The present invention provides a new method of mak-ing zipper profile film web, comprising extruding a plurality of separate plastic fastener strips in close proximity to one another and at the same production speed, effecting continuous running travel of a web of substantial width at the same speed as the extrusion production speed of said fastener strips, ad-justing respective positions of the fastener strips transverse-ly relative to the web and into substantially spaced relation to one another, then guiding the fastener strips as thus adjusted as to position, without interruption after extrusion ;~
of the strips, into longitudinal positions convergently onto the web, and permanently securing the travelling fastener :
strips to the travelling web.
The invention also provides new apparatus for mak-ing zipper profile film web, comprising means for extruding a plurality of separate plastic fastener strips in close proxi-mity to one another and at the same production speed, means for effecting continuous running travel of a web of substant;al width at the same speed as the extrusion production speed of said fastener strips, means for guiding the fastener strips from the extrusion means into longitudinal positions relative to the web and in substantially spaced relation of the fastener strips to one another on the web, means for selectively adjusting said guide strips to one another on the web, means for selectively adjusting said guide ."~

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means to effect adjustments of the respective positions of the fastener strips transversely relative to the web, and means for effecting convergence and for permanently securing the travelling fastener strips to th~ travelling web.
The invention further provides a new method of mak-ing zipper profile film web, comprising effecting continuous running travel of a web of substantial width r extruding one plurality of separate plastic fastener strips adjacent to one longitudinal edge of the web and at a production speed equal to the running travel of the web, extruding a second plurality of separate plastic fastener strips adjacent to the opposite longitudinal edge of the web and at a production speed equal to the running travel of the web, guiding the extruded fasten-er strips transversely across the web into respective longi-tudinal positions for the fastener strips, at such longitu-dinal positions guiding the fastener strips into parallel longitudinal running relation with the web, adjusting the fastener strips transversely relative to the web and to one another, and effecting convergence and permanent securement of the fastener strips to the travelling web.
There is also provided by the present invention a new apparatus for making zipper profile film web, comprising means for effecting continuous running travel of a web of substantial width, an extruder adjacent to one longitudinal

2~ edge of the web and operating to extrude a plurality of separate plastic fastener strips in close proximity to one another and at a production speed equal to the running speed of the web, a second extruder adjacent to the opposite longi- :
tudinal edge of the web and operative to extrude a plurality .. . . .. .. .. . . . .

of separate plastic fastener strips at a production speed equal to the running speed of the web, guiding means operat-ing to guide the extruded fastener strips transversely across the web into respective longitud:inal positions for the fastener strips, said guiding means also operating at said lonyitudinal positions to guide the fastener strips into parallel longitudinal running relation with the web, means for adjusting the guiding means for adjusting the respective posi-tions of the fastener strips transversely relative to the web, and means for effecting convergence and permanent securing of the travelling fastener strips to the travelling web operative after the fastener strips have been guided by said guiding means to said parallel running relation to the web.
Other objects, features and advantages of the inven-tion will be readily apparent from the following description of a representative embodiment thereof, taken in conjunction with the accompanying drawings although variations and modifi- ;
cation may be effected without departing from the spirit and scope of the novel concepts embodied in the disclosure and in which:
Fig. 1 is a schematic elevational view of means for practicing the invention.
Fig. 2 is an enlarged fragmentary side elevational -~
view taken substantially in the plane of line II-II of Fig. 1.
Fig. 3 is a schematic edge view of a film web equip- ~`
ped with fastener strips according to the present invention and adapted for making open top bags. -~
Fig. 4 is a schematic edge view of a film web equipped with fastener strips according to the present invention adapted for making bottom open bags.
Fig. 5 is a fragmentary sectional elevational view - taken substantially along the line V-V of Fi~. 2; and Fig. 6 is a fragmentary side elevational view similar to Fig, 2 but showing a mcdification.
On reference to Fig. 1, at least one, and in this instance a plurality such as four continuous profiled resiliently flexible extruded plastic fastener strips 10 and a continuous -film web 11 which may also be formed from extruded plastic material are caused to travel in the same lon~itudinal direction and at the same speed. The fastener strips 10 are adjusted as to position relative to the width of the web and to each other and guided into convergence with the web 11, and then permanentlv secu red to the web. For bag making, plastic material most appropriate for the mechanical and optical qualities desired, in either or both of the fastener strips and the film, should be chosen. For example, the web 11 may be formed from polypropylene and the fastener strips may be made from polyethylene where the fastener strips and the web are to be adhesively attached to one another. On the other hand, where the fastener strips are to be fused to the web they may both be made from the same material, or at least from rnaterials which are 3~usibly compatible.
An extrusion of the fastener strips 10 may be by ~$~

means of one or more, in this instance two, extruders 12 which extrude the fastener strips through suitab]e die orifices to produce the desired profiled strip section. For convenience ancl compactness of apparatus, the fastener strips produced by each of the extruders 12 are projected from the extruder in close proximity into and through a chilling device 13 in which thc hot plastic extruded fastener strips are subjected to a cooling medium such as water and from which the fastener strips travel continuously toward union with the web 11. In the illustrated example, two of the fastener strips 10 are produced at one side of the web 11 and two of the fastener strips 10 are produced at the opposite side of the web.
Although the web 11 may be supplied from a roll where it may comprise a non-plastic material, or where it ma~
be a composite plastic and non-plastic material and thus desirably prefabricated at a different place and at a different speed than that of the assembl~ and joining speed of the fastener strips to the web, in a more usual arrangement for producing bag making zipper profile film web, the web 11 is extruded through a suitable elongated orifice from a T-die 14 of an extruder 15 For example, the plastic film web 11 may be a flat sheet of about 60 inches (150 cm). Since both the fastener strips 10 and the web 11 are prefabricated before joining them and since the fastener strips are extruded and chilled separately from the web 11, production of the fastener strips and the web and joining them can be effected at high speed such as about 650 to lO00 feet per minute (200-300 m/mn), especially where attachment of the fastener strips to the web is effected adhesively.
Means for guiding and applying the fastener strips lO to the web l1 comprise, for each of the fastener strips 10, an ang1ing guide roller 17 over which the strips are guided from a path which generally parallels the adjacent ec3ge of the weh ll to a direction transversely inwardly relative to said web and to an angling roller l 8, over and from which the fastener stril-trave1s onward again longitudinally with the web ll in the desired orientation for assuming its attached position on the web. The rollers 17 may be rotatably mounted in fixed position by mealls of brackets 19 (Fig. 2) carried on a machine frame 20.
Mounting of the ang1ing rollers 18 is effected by 1~ means permitting adjusting of the fastener strips 10 transverselv relative to the web 11 without interrupting the continuous travel of the fastener strips and web. For this purpose, the rollers l 8 ;
are mounted on respective adjustment arms 21 extending longitudinally relative to the travel of the web ll, with said arms mounted adjustably on a bar or beam 22 which extends transverse1y in a suitab1y spaced re1ation to the path of travel of the web ll, and is fixedly mounted at its opposite ends such as by means of rigid arms 23 to the frame 20. In one con~enient manner of mounting the arms 21, each of them has a rigid slide block 24 on its end opposite the supported roller , 7'3 18, with the slide block being slidably engaged on the beam 22 so as to permit incremental transverse adjustment with respect to the web 11, To fix the block 24 in each instance releasably in adjusted position along the beam 22, releasable retaining means such as a set screw 25 may be carried by each of the block s .
The length of each of the arms 21, and its spaced relation to the path of travel of the web 11 is such that an additional mechanism can be carried by the arm and the associa-ted mounting block 24 for handling and attaching the associated fastener strip 10. Desirably a fastener strip guide 27 is carriecl by the arm 21 for accurately directing the fastener strip convergently toward the web ll. Downstream from the guide 27, means are provided for attaching the fastener strip 10 to the web 11, and in one desirable form comprising an adhesive applicator 28 having a nozzle 29 from which suitable adhesive 30 is deposited between the interface area of the web 11 and the fastener strip 10 adjacently upstream from where the web and strip converge. Liquid adhesive is supplied to the applicator 28 from any suitable source as by means of a conduit 31.
Mounting of the applicator 28 is desirably by means of an auxiliary arm 32 fixed to the block 2~ of the associated supporting arm 21. After application of the adhesive 30, a presser roll 33 presses the web sections of the fastener strip 10 firmly against !;
the web 11 which at this point is supported by a backing roll 34 . . , , , ~ ;. ., ., ~ ....

mounted rotatably on the frame 20. Conveniently, the presser roll 33 may be journaled on bearing bracket means 35 also carried by the auxiliary arm 32, with resilient spring biasing means 37 acting on an axle 38 of the roller 33 to thrust the roller yieldably toward the webs of the fastener strip 10.
Although each of the arms 21 has a separate presser roll 3 associated therewith, the backing roll 34 is common to the entire array of presser rolls, and desirablv extends entirel~
across the web 11. Through this arrangement, each of the arms 21 and the associated fastener strip guiding and attaching mechanisms are adapted to be incrementally adjusted transversel~
relative to the web 11, for adjusting the position of the associated fastener strip in longitudinal orientation with the web 11, fo~
any variable bag size desired to be made therefrom while the fastener strips and the web continue travelling uninterruptedly at high speed. It will be understood that any suitable means may be provided downstream from the point of attachment of the fastener strips to the web 11 for maintaining the web and fastener strips in continuous onward travelling motion coordinated with the speed of extrusion of the fastener strips and thc web.
For some purposes, it may be desirable to wind the fastener carrying web on a roll. On the other hand, the fastener carrying web may go directly to processing apparatus such as bag making apparatus where the web may be slit into a plurality of suitable widths zipper profile film strip sections which are suitabl~ folded .

into U shapes for forming into bag units. Any such means are represented schematically at 20a (Fig. 2), As best seen in Fig. 5, each of the fastener strips 10 may be of a width to carry integrally thereon a barbed male fastener profile 39 in spaced parallel relation to a groovecl complementary female profile 40. To accommodate the profiles 39 and 40, the presser roll 33 is provided with respective clearance grooves 41 and 42 which also assist in guiding thc fastener strips accurately into position on the web 11, utilizing the profiles 39 and 40 as guide means for the strip.
For high speed operation, the adhesive 30 is desirably a hot thermofusible synthetic resin adapted to bc applied at a temperature of about 390 to 460"F. (150G - 190 c) in a layer of about . 00~ inch (.10 mm) at a speed up to 1000 f~
per minute (300 m!mn), sufficiently tacky to retain the attache:3 fastener strip on the web and to set in about 3 to 5 seconds after being applied.
Where it is preferred to attach the fastener strip ~ -to the web by electronic or heat fusion, the arrangement of Fig. 6 may be employed. For this purpose, the guiding and supporting arm 21' may be of substantially the same construction and function similarly as the arm 21 already described, supported on a slide block 24' slidably mounted on the beam 22' to which it is adapted to be locked in adjusted position by means of a set screw 25'. In addition the arm 21' carries the guide 27'.

However in this instance, there is mounted on thc: block 24' in association with the arm 21' an electronic welding roll 43 rotatably carried by a bracket 44 Oll an auxilliary arm 45 suppor-ted by the block 24'. To accommoclate the fastener strip profiles, 5 the welding roll 43 is grooved similarly as the roll 33. The roll 43 is suitably electronically or heat powered and presses the webs of thc fastener strip 10 against the web 11 towarcl a cooperating backing roll 47 which may be supported by bracket means 48 carried by the machine frame and biased toward thc 10 back of the web 11 by means of biasing springs 49 acting against an axle 50 of the roll 47. Through this arrangement, as the fastener strip 10 converges with the web 11 at high speed, the roll 43 permanently e1ectronically or heat welds the strip to the web .
Whether the fastener strips are adhesively, electroni-cally or heat attached permanently to the film web, the reclosable plastic fastener strips may carry fastener profiles arranged for either top opening or bottom opening bags. For top opening bag purposes, the arrangement of fastener strips on the web may bc 20 substantially as exemplified in Fig. 3 wherein the web 11' has attached thereto at suitably spaced intervals fastener strips 1()' carrying a pair of integral laterally spaced male profiles 39' with such strips 10' alternating with fastener strips 10" having a pair of integral laterally spaced female profiles 40'. ln 25 suitably spaced adjacency to the respective opposite longi tudinal '7~

edges of the sheet web 11' are attached a fastener strip 10a having thereon a female profile 40" and a fastener strip lOb having thereon a single male profile 39". The fastener strips 10', 10", 10a and 10b are so disposed relative to one another that when the web 11' is severed along lines 51 medially between the male and femal profile pairs 39' and 40', respectively thc resulting zipper profile film sections are adapted to be folàed along lines 52 midway between adjacent male and female profi]es to bring said male and female profiles into fastened relationship, thereby providing open top bags wherein the portion of the film between the fastener strips is foldecl to provide the walls of the bag with said bag having a closed bottom and being openable at the top by separating the resiliently flexible zipper fastener. It will be understood, of course, that as is usual practice, the folded film section will be transversely sealed at suitable intervals to provide bag units. It will be observed, of course, that for ma~imum yield, the web 11' in the illustrated example has been provided with six fastener strips. This shows that there is no necessar~ limit on the number of fastener strips that may be applied to a travelling film web, within the parameters of practicability and apparatus capacity.
For producing bottom open bags, having reference to Fig. 4, the web 11 having attached thereon the fastener strips 10 each provided with an integra] male profile 39 and an integral female profile 40, is adapted to be severed along longitudinal lines 53 midway between the fastener strips 10 and folded along longitudinal lines 54 midway between the profiles 39 and 40 of each of the strips to bring the profiles into mating fastener c]osed relation. Thereby the portions of the zipper profile film sections at each side of the fastener strip 10 in each instance provide wall panels for open bottom bags. It will be understood that after folding of the web film sections, the sections are transversely sealed at suitable intervals and separate~ into hag units. Such open bottom bag units can then be filled thro~lgll their open bottoms and the openings sealed to provide bags which are completely hermeticallv sealed until they are opened for access to the contents by severance, as by snipping the bags open a~ong substantially the fold lines 5~, whereby the fasteners of thc bag can then be opened by manually separating the fastener profiles 39 and 40. After thus opening the bags, they can be readily reclosed by again joining the fastener profiles 39 and 40.
Although two examples of fastener and film web ori-entation and bag making potential have been described, it will be apparent that numerous and varied other fastener orientations and arrangements may be attained according to the principles of the present invention. A salient new and improved result attained by the present invention is the capability of varying the width of the zipper profile filrn, that is the strip sections into which the sheet web is severed, in any desired combination without ever having to stop the continuous running travel of the fastener strips 2'7~

and web. This result is achieved by the facility of incremental transverse adjustment of the positions of the fastener strips on the travelling web as desired without interrupting continuous high speed travelling flow of the fastener strips and the web. Such freedom from interruption in the continuous travelling flow includes the extrusion process.

Claims (12)

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

1. A method of making zipper profile film web, com-prising extruding a plurality of separate plastic fastener strips in close proximity to one another and at the same pro-duction speed, effecting continuous running travel of a web of substantial width at the same speed as the extrusion pro-duction speed of said fastener strips, adjusting respective positions of the fastener strips transversely relative to the web and into substantially spaced relation to one another, then guiding the fastener strips as thus adjusted as to position, and without interruption after extrusion of the strips, into longitudinal positions convergently onto the web, and perma-nently securing the travelling fastener strips to the travel-ling web.

2. A method according to claim 1, comprising ex-truding the plurality of fastener strips from a plurality of extruders, and guiding the fastener strips from the plurality of extruders into longitudinal positions relative to the web.

3. A method according to claim 2, comprising ex-truding one plurality of the fastener strips adjacent to one longitudinal edge of the web and another plurality of fasten-er strips adjacent to the opposite longitudinal edge of the web, guiding the extruded fastener strips transversely across the web into respective longitudinal positions for the fasten-er strips, and at such longitudinal positions guiding the fastener strips into parallel longitudinal running relation with the web and then effecting permanent securing of the travelling fastener strips to the travelling web.

4. A method according to claims 1, 2 or 3, com-prising extruding the web as a plastic film web from an extru-der separate from the fastener strip extruders and at the same production speed as the extrusion production speed of the fas-tener extruders.

5. Apparatus for making zipper profile film web, comprising means for extruding a plurality of separate plastic fastener in close proximity to one another and at the same pro-duction speed, means for effecting continuous running travel of a web of substantial width at the same speed as the extru-sion production speed of said fastener strips, means for guid-ing the fastener strips from the extrusion means into longitu-dinal positions relative to the web and in substantially spa-ced relation of the fastener strips to one another on the web, means for selectively adjusting said guide means to effect ad-justments of the respective positions of the fastener strips transversely relative to the web, andmeans for effecting con-vergence and for permanently securing the travelling fastener strips to the travelling web.

6. Apparatus according to claim 5, comprising a plurality of extruders for extruding the plurality of fastener strips, and said means for guiding being operative to guide the fastener strips from the plurality of extruders into the longitudinal position relative to the web.

7. Apparatus according to claim 6, wherein one of the extruders operates to extrude one plurality of the fasten-er strips adjacent to one longitudinal edge of the web and another extruder operates to extrude another plurality of fastener strips adjacent to the opposite longitudinal edge of the web, the guiding means operating to guide the extruded fastener strips transversely across the web into the respec-tive longitudinal positions for the fastener strips, said guiding means also operating at such longitudinal positions to guide the fastener strips into parallel longitudinal running relation with the web, and said means for effecting permanent securing of the travelling fastener strips to the travelling web being operative after the fastener strips have been guided by said guiding means to said parallel running relation to the web.

8. Apparatus according to claims 5, 6 or 7, com-prising means for extruding the web as a plastic film web from an extruder separate from the fastener strip extruders and at the same production speed as the extrusion production speed of the fastener extruders.

9. A method of making zipper profile film web, com-prising effecting continuous running travel of a web of sub-stantial width, extruding one plurality of separate plastic fastener strips adjacent to one longitudinal edge of the web and at a production speed equal to the running travel of the web, extruding a second plurality of separate plastic fasten-er strips adjacent to the opposite longitudinal edge of the web and at a production speedequal to the running travel of the web, guiding the extruded fastener strips transversely across the web into respective longitudinal positions for the fastener strips, at such longitudinal positions guiding the fastener strips into parallel longitudinal running relation with the web, adjusting the fastener strips transversely relative to the web and to one another, and effecting con-vergence and permanent securement of the fastener strips to the travelling web.

10. A method according to claim 9, comprising ex-truding the web as a plastic film web from an extruder sepa-rate from the fastener strip extruders and at the same pro-duction speed as the extrusion production speed of the fasten-er extruders.

11. Apparatus for making zipper profile film web, comprising means for effecting continuous running travel of a web of substantial width, an extruder adjacent to one longi-tudinal edge of the web and operating to extrude a plurality of separate plastic fastener strips in close proximity to one another and at a production speed equal to the running speed of the web, a second extruder adjacent to the opposite longi-tudinal edge of the web and operative to extrude a plurality of separate plastic fastener strips at a production speed equal to the running speed of the web, guiding means opera-ting to guide the extruded fastener strips transversely across the web into respective-longitudinal positions for the fastener strips, said guiding means also operating at said longitudinal positions to guide the fastener strips into parallel longitudinal running relation with the web, means for adjusting the guiding means for adjusting the respective positions of the fastener strips transversely relative to the web; and means for effecting convergence and permanent se-curing of the travelling fastener strips to the travelling web operative after the fastener strips have been guided by said guiding means to said parallel running relation to the web.

12. Apparatus according to claim 11, comprising means for extruding the web as a plastic film web from an ex-truder separate from the fastener strip extruders and at the same production speed as the extrusion production speed of the fastener extruders.