CA1277640C - Single hinge interlocking closure profile configuration - Google PatentsSingle hinge interlocking closure profile configuration
- Publication number
- CA1277640C CA1277640C CA 471202 CA471202A CA1277640C CA 1277640 C CA1277640 C CA 1277640C CA 471202 CA471202 CA 471202 CA 471202 A CA471202 A CA 471202A CA 1277640 C CA1277640 C CA 1277640C
- Grant status
- Patent type
- Prior art keywords
- closure element
- fastening device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D33/00—Details of, or accessories for, sacks or bags
- B65D33/16—End- or aperture-closing arrangements or devices
- B65D33/25—Riveting; Dovetailing; Screwing; using press buttons or slide fasteners
- B65D33/2508—Riveting; Dovetailing; Screwing; using press buttons or slide fasteners using slide fasteners with interlocking members having a substantially uniform section throughout the length of the fastener and operated without a slider
- B65D33/2541—Riveting; Dovetailing; Screwing; using press buttons or slide fasteners using slide fasteners with interlocking members having a substantially uniform section throughout the length of the fastener and operated without a slider characterised by the slide fastener, e.g. adapted to interlock with a sheet between the interlocking members having sections of particular shape
- A—HUMAN NECESSITIES
- A44—HABERDASHERY; JEWELLERY
- A44B—BUTTONS, PINS, BUCKLES, SLIDE FASTENERS, OR THE LIKE
- A44B19/00—Slide fasteners
- A44B19/10—Slide fasteners with a one-piece interlocking member on each stringer tape
- A44B19/16—Interlocking member having uniform section throughout the length of the stringer
Abstract An interlocking closure fastening device comprising an omega-shaped closure element and a co-acting clamping closure element. The co-acting clamping closure element may have a profile portion comprising two generally parallel arm portions wherein one of the arm portions terminates in an inwardly curved hook portion, and the other arm portion curves slightly inward prior to terminating in an outwardly extending clamp portion; or the profile portion may comprise two outwardly curved arms portions wherein one of the arm portions terminates in an inwardly curved hook portion, and the other arm portion curves inwardly prior to terminating in a slightly outwardly curved hook portion; or the profile portion may comprise one inwardly curved arm portion terminating in an inwardly curved hook portion, and one generally straight arm portion.
1 Fi el d o f the Invention T~i~ inven~ion relate~ to an interlucking clo~ure fa6tening de~ice, and ~ore particularly, to an interlGcking closure fastening device ~omprising an omega 6haped ~lo~ure ele~en~ and a co-acting clamping clo~ure ele~ent.
B~ckqround of the Invention ~n gener~l, clo~ure fastening devices for use in connection wi~h pla~tic bags and ~he like are known. Furthermore, manufaoturing methods for closure f~tening device~ made of plastic ma~erial are generally well known.
In opera~ion, a clo6ure fa6tening device ~or u~e in con~ec~ion with a flexible container ~hould be relative~y easy to open from tbe ou~sideO
bu~ relatively difficul~ to open from tbe i~ide.
; Gener~lly, ~uch ~ con~ainer can be u~ed with its in~erior either under relatively high pressure or under relatiuely low pre~6ure. Th~ cln~ure fa~ening device ~hould psovide a ~at~ac~ory 6eal ~r either condition.
Preferably, t~e clo~ure fastening de~ice uld be ~itable for econo~ical manufacturing and 2~
6bould b~ ~elatively 6i~ple in de~ign. ~ ~ad~tion~
t~e d~ign should p~ovide for varia~ionD in s~d~ ~o me~t ~ifferent. need~. For ex~mple, it m~y be dexirabl~ to have a clo6ure fa~tening device w~ich S i6 r~lativ~ly difticul~ ~o open bot.h trom th~ inside and a~e out~ide. In qeneral, th~ elo6ur~ ta6t~ning device, ho~vez, ~ould alway~ ~e relatively ea~y t.O
In ~ddition, ~hen t~e closure fa6tening device iB employed with a container, the container may be made from a thermoplastic material and the clo~uFe devi~e and ~idevall6 of t~e con~ainer can be ~ade inte~rally by ext~u6ion a~ a unitary pi~ce or can be made a~ ~epar~te co~po~ent6 whic~ are su~eguen~ly ~e~manently connected toge~her.
Ho~ev~r, ~he ther~opla~ic re~in material6 heretofore o~nd prac~ica~ for the extsu~ion of interlocking clo~ure devices, and their a~t3chment to f ilms, ~uch a6 in making container~, have re~ulted in 6hrin~age and distortion problems during ~eir u~e at elevated temperature~. Typical resin material6 employed ~or interloc~ing clo~ure devices and containe~ film6 have included polyethylene, polyvinyl chloride copolymers, and ~ynt.betic rubbers. However, none of t~e~e construction material~ ~ave 6ufficient ~hermal tolerance for n,any con~mercial u6es. Further, both occlu~ion and deocclu~ion of t~e in~erlocking clo~ure device is generally ditficult for the u6er when the device i~
made fro~ re6in materials having ~ig~ ~e~perature t~lerance~ due to their a660ciated high flexural moduli.
1 Summarv of the Invention The foregoing criteria for a closure ~astening device are met by one embodiment of the present invention wherein the fastening device includes a first closure element having a general omega shape comprising an apex portion, and a profile portion ~xtending from the apex portion, said apex portion being generally flat or slightly arcuate, and said profile portion comprising two inwardly curved arm portions terminating in two outwardly facing, curvilinear hook portions. The closure device includes a second closure element having a generally flat or slightly arcuate apex portion, and a profile portion extending from the apex portion. The profile portion of the second closure element comprises first and second generally parallel ar~ portions wherein one of the arm portions terminates in an inwardly curved hook portion, and the other arm portion curves slightly inward prior t~ terminating in an outwardly : extending clamp portion. The first closure element and the second closure element are adapted to disengage and engage each other by means of a torquing action so as to form a straddling type of occlusivn.
In another embodiment of this invention, the fastening device includes a first closure element having a general omega shape comprising an apex portion, and a profile portion extending from the apex portion, said apex portion being generally flat or slightly arcuate, and said profile portion comprising two inwardly curved arm portions terminating in two r-,.. ..
, - ~2~76~
1 outwardly curving h~ok portions. The closure device includes a second closure element having a generally flat or slightly arcuate apex portion, and a profil~
portion extending from the apex portion. The profile portion of the second closure element comprises two outwardly cur~ed arm portions wherein one of the arm por~ions terminat~s in an inwardly curYed hook portion, and the ~ther arm portion curves inwardly prior to terminating in a slightly outwardly curved hook portion. The first closure element and the second closure element are adapted to disengaga and engage each other by means of a torquing action so as to form an overlapping type o~ occlusion.
In a ~urther modification of the preceding embodiment, the profile portion of the second closure element comprises two outwardly curved arm portions whexein one of the arm portions terminates in an inwardly curved hook portion, and the other arm portion curves progressively inwardly as to make contact with one of the arm portions of the first closure element when the fastening device is occluded, prior to terminating in a slightly outwardly curved hook portion.
In a further embodiment of this invention, the fastening device includes a first closure element having a general omega shape comprising an apex portion, and a profile portion extending from the apex portion, said apex portion being generally flat or slightly arcuate, and said profile portion comprising two inwardly ourved arm portions, an outwardly 1 extending arm portion from each of said inwardly curved arm portions, each of said outwardly extending arm portion terminating in an outwardly curved hook portion~ The closure device includes a second closure element having a generally nat or slightly arcuate apex portion, and a profile portion extending from the apex portion. The profile portion of the second closure element comprises one inwardly curved arm portion terminating in an inwardly curved hook portion, and one generally straight arm portion extending from said apex portion in a generally perpendicular direction therefrom. The first closure element and the second closure element are adapted to disengage and engage each other by means of a torquing action so as to Porm a straddling type of occlusion.
; Brie~ Description of the Drawinas Fig. 1 is a cross-sectional view of one embodiment of the closure fastening device in accordance with this invention in an occluded position;
Fig. 2 is a cross-sectional view of another embodiment of the closure fastening device in accordance with this invention in an occluded p~sition;
Fig. 3 is another cross-sectional view of the embodiment of the closure fastening device shown in Fig. 2;
Fig. 3-A is a cross-sectional view of a closure fastening de~ice shown in Fig. 3 to illustrate typical physical dimensions;
Fig. 4 i~ ~ cross-6et~0n~1 viev og th~
clo~ure fa6teaing d@vic~ shovrl in Fi~ in ~n~
- occluded po~itio~, in ~ pa~tially deoccluded po~i~ion, ~3nd in a d~oc~luded po6ition;
~ig. 5 i~ a oro6~ c~ional view o a preferred embodiment o t~le clo6ure fa~tening de~rice in a~cord3n~2 witlb ~his inv~ntion in a parltially d~occ~uded po~i~ion;
Yig. b i~ a cro~s-sectior~l view of anorher embodiment. of r~e clo~ure fa~tening device in 2ccordance Wilb ~t~i6 inven~ion in a deocclud~d po6itior~;
Fi~ a cros~-sectional vie~ of the closure fa~ening d~vice 6ll0wn in Fig. ~ in an occluded pDsition; and ~ig. ~ i~ 3 cro~s-~ectiona} view or t~le clo~ure lEa~tenin~ device 6hown in ~ig. 7 in a partially deoccluded p~ai~ion during deocclu6ion.
Detailed De~cri~ion of the Preferred Embodiments The clo6ure f a~ening device of the in~tant invention may be made from a ~h~rmoplastic rnaterial selec~ed fron- the g~oup consisting of polyolef ins 5uch a~ poly~t~lylene, polypropylene, and polybutylene; polyamide~ such a~ nylon; or o~her t~ermopla6t ic mat.erial~ including combina~ions thereo~. The clo6ure fastening devioe is prefe~ably made ~rom a thermopla~ti~ re6in composition comprisirlg polypropylene, or a mixture of polypropylene tesin and et~ylene-propylene-diene m~nomer elastomer. ~r a ~ixt~re ot polypropylene resin ~nd ethylene-propylene copolymer ela~to~er.
T~e dimen6ion~ of the c~06ure f.3~enin~ device ~ay 7~ 7 .
~Dry in accotdanc~ h in~.~ndæd u~ nd ~epes!ding upon ~be ~aterial~ ~çed in ~ei~ ~anufacture be~au ot the varia~ions in phy6i~al propertie~, ~ucn ae 1~xu~al ~oduli.
~`~e c~O6U~e ~a6t~nin~ devic~ o~
inven~ion can be ~anufactured by known metnods 6ucb a6 by extru~ion, by the u8e 0~ mold6 or other known met~od~ of eroducing such devices. T~e closur~
fa~tening d~vice can be manufaeSured as a 6t~ip for later attac~ment. to a fil~ or it. can be manufactured intogr~l ~ith ~e film. I~ ~ddition, ~he closure devise can be ~anufac~ured wit.h or wi~bout. ~lange6 on one or botb o~ t~e clo~ure elementsO dependinq u~on int*nded uce or expec~.e~ a2~i~ional manufactu~inq op@ration~.
T~e clo6ure element6 can be connected to a contain~r or t.o a fil~ ~o be ~orm~d into 2 C~ntairler by ~e u ~ of ~a~y known method~. For exam~le~ a ther~oelec~ric device can be ~ppli2d ~.o a film oppo~ite a clo~ure element to cau~e ~ transfer of heat t~rough t~e fil~ t.o produce melting at the intertace of t~e ~ilm and tbe closure elemen~.
A~ter ooolinq, the in~erfaee re~ion join~ ~he film and the closure el~ment.
l'he ther~o~l~c~ic device can be heated ~y ro~dry di6~, or resi~tance heated vires, or t.raveling heater band6, or t.he like.
The connection berween t~e tilm and the closure element can al~o be establi~ed by the use of ~o~ ~elt adtlesive6, or ~t jet.s ot aiE to t~e interSa~e, or ultr~60nic ~eating, or nther known meth~d~.
S;enes~lly, t~ ~re6ent. clo~ur~ ~6tenlng devie~ C~l be n~d~ from ~ ~ea~. ~e~lable ~eri~l snd ~llen ~t~che~ ~o ~ Inle~t 6~alable ~ilm 60 tb~t ~
cont3iner can be ~ar~ed economi~:ally by ~eat 6ealing ~urf 3ce~ to f or~ tb~ cont~iner .
lrhe in~tant clo~ure f a~ter~ g device pro~ide~ ~any advantaq~ f~r Consumer~ when u~ed on container~. For in~t~nce, i~ i~ e~E;y to ~los* a ~ontainer because ~e clo6~re element.s t.orque ~r 0 twist with respe~t to ~clh otber from the deoccluded t~ t.hP c>~cluded p~iti,c>n wi~h litt.le effort in ~pite of the hign flexural modul~ of the temperature re6ifi2ant re~in6 l~ed. The ~ctic~n ~s~ntra~ littl prior art ~truc~ure~ ~uc:h 2~ rr~w type of closures wtleret in the female elen~ent 6, ~he ht)c~hed sides ~lave to be bent or ot~lerwi6~ di~tort~d for ~ccl~iion or deocclu~ion. ~n a prior ar~ Channel closure ~ ba~e portion ~a~ to be bent. t.o accompli6~ occlu ion or deocclu~ion. And 6t.ill anottler 6t.ructure made very ~iff, requires longitudinal di~placemen~ to a r,on-hvok~d end before t~e ~le and female elements can ~e pried apart by ~ t.ic bending of portions of eac~ elemen~.
For a ~uller under~arlding ~f the natu~ of the invention, reference 6~l0uld be had to the follo~ing detail~ de6cription. taken in ~onjunction with the accompanying dr~wings.
~'i9. 1 iB ~ cros~-~ection~l view of one e~bodiment of t~e clo6ur~ ta~tening device in accordance wittl t.hi6 ~nvention, in an occluded po~ition. A6 6~0wn therein, ~ first ~Hh~i~}e ~lo~ure element 10 ~Yin9 ~ general omega ~ape is 7 7~.3 connect~d ?o ~ f lange portior~ or u~
conn~ct iorl to a th~rmo~las~ic til~a. Closure ~le~ent 10 ha~ an apex por~ion ~2 blhi~h ili typic~lly ~ or 61igt~t~y arcuateO and extending fronr apex portion lZ
is a prof il~ portion wtlietl ~ompri~s t~o in~-1ardly ~urved afm portion6 1~ and 13~ whic~t terminate in t~o outwardly curving llook por~ions 14 and 19~, ,~ ret;pectively. A 6econd- clo6ure element 15 is shown connected ~o a f lange por~ion 16, and it comp~ise~ an apex por~ion 17 b~hich may tlaYe a flat or ~ligh~ly arcuate oonf igura~ion. Exeending f rom ~pex por~i~n 17 is a pro~ po~tion co~pci~ing tWO
gea)el~ally p~r~ l arrn portion~ 1~ and 1~ ~ . Arm portios~ terminates irl an inwardly cu~ed hoc~
portion 19, ~lerea~ arm portion 18 ~urves 61i~htly inwardly prior to terlainat.ing in an outw~rdly extending clantp portion ;20. A~ 6hown in Fig. 1, when the clo6ure fa~tening d~vice is in ~n o~e~uded po6it ic~r~. hook portion 1~ ~ of ~lo~lure elemerlt lV and hook portion ~9 o~ clo~ure ele~en~. 15 are is~terlooked, and arm portion ~ ~nd clamp portion ~O
of clo~ure elenten~ 15 ar~ in locked cont.~ct witb ar~
,! port ion 1~ 0~ clo~ure e~ement 10. I~ can al~o be ~een ~ron~ ~ig. 1 tha~ ar~ ~ortion 1~' terminat~ng in inwardly curved ~ook portiosl 1~ is adapted to engage in a hinging con~act wit~ arm portion 1~' ~ernlina~ing in out~ardly curving hook portion 14'.
and arm por~ion 1g terminating in outwardly ext~ndillg portion 20 is adap~ed ~o engage in a 3~ clamping conaact with arm porton ~ termina~ing in ou~wardly curYing hooh ~or~ion ~. As can be ~een from Fig. 1, clo~ure ~lemen~ 1~ and closure ele~ent -` . 927~
, 15 for~ a stradaling occlu~ion wberein ar~ ~ortion 1~ ~nd clamp portion ~ of closur~ el~n~ lS ~re po6itioned be~ween ar~ portion~ 1~ and 13~ oP
clo~ure element 10. ~hen tbe closur~ ~astening devic~ i~ connec~ed to a p~a~tic container, ~r~
~ortion 13 and nook portion 1~ ~re positioned clo~e~t l.o t~e mou~h or out~ide portion of t.he containet, and ar~ portion 1~ i6 positioned close~t to t~e interior o~ in6ide pottion of t~e container.
0 Fig. 2 i~ a cross-sectional view of another embodi~ent of t~e clo6ure fa~tening device i~
a~cordance ~it~ ~his invention. in an ocGl~ded po6i~ion. ~ ~ay be ~een a~erefrom ~hat the first ~}eYnb~e closure element 21 ha~ a general omega lj ~hape, and that i~ ~ay be connec~ed t~ a 1anqe portion 22 ~Ol connection ~o a t~er~opla~tic til~.
Closure element 21 ha~ an a~ex portiorl Z3 w~ich is : 61ig~1y arcua~e or generally flat. and extending from a~ex portion 23 is a pro~ile portion ~ich ~ co~pri~es tvo inwacdly curved as~ portion~ 2q ~nd 24~ which ~erminate in t~o outwardly cucving ~ook porti~n~ 25 and 25~, respectively. ~ ~ecor~d ~e~ clos~re elen~ent ~ is ~own connested to a fl~nge portion ~70 and i~ compri~e. an apex por~ion 28 which ha~ a fla~ or ~lightly arcuate configuration. Extenaing from apex por~ion 2~ i~ a profile portion conlpri~ing two outwardly curving arm portion6 29 and 29'. Arm por~ion Z9~ terminate~ in an inwardly curved ~oo~ ~or~ion ~0, and arm ~ortion 29 curve6 inwardly prior to ter~inating in a s~igh~ly ou~ardly Curvea book por~ion ~. From Fi~. 2. it may be 6een that ~hen tbe clo~ure 2~76~
fa6tening deva~ i6 i~l ~111 o~cluded po6itioA, h~ok portion ZS ~ of clo~ure e~em~n~ 21 an~ boo~ port~on ~0 o clo6ure l~lement. Z~ are interlockedO whil~ ~r~
por~ion ;29 ~n~ l~ool~ ~ortion 31 o~ clo6ure element 26 are in contac~, ~?ith hoo~ pos~ioo 25 of clo~ure element Zl. tt. ean al60 be ri,e~n f rom Fig. ;2 tha~
arm portion 29 ~ ter~inating ill in~ardly cufved hook port ion ~0 is ~dapt~d to engage in a tlingins contac~
with arm portion 24 ~ ternlinatin~ in outwardly curving hook po~tion ~5~, and arm por~ion ~4 ~ernlinating in ou~rdly curving ~look portion ;25 i~
adapt~d to eDgage in a clamping contac~ wit.h ~rm portion ;29 t~rnlinating in outwardly curved hook portion 3~. ~t ~an uEther ~e ~een fro~ Fig. 2 ~hat closure element ~1 ~nd clo~u~e element 2~ for~ an overlapping type ~f ~slu&ioo wherein ~oo~ por~ion ~0 of clo~ure ~lemeat Z6 overlaps hovk por~ion 25~
o~ r~osure ele3n~n~ 21, and arrD portion ~ and hook portion 31 o~ closure ~len~ent. ~6 overlap hoolt portion Z5 of clo~u~e ~lement 21. When thus oocluded, arm portion 29 and hook portion ~1 o~
clo~ure element. 260 and hook por~ion 25 of olosure elemen~ 21, tog~ther form an easily di~enga~able s~ruc~ure, while hook por~ion ~0 of closure element ~ and hoo~ portion 2$~ of closure element Zl form a hinge ~tructute which is stron~ly resi~tan~ to deocclu6ion ~i~hout considerabl~ rotation.
Fig. ~ i~ a free body diagram showing a cross-6ectional vie~ ot the closure fastenin~ device ~hown in Fig. ~. Th~ first fUe~i~rhr closure elemen~
A ~1 shown tbeeein i~ the sam~ as that 6~0w~ ~ Fig.
Z. However, ~he rieoond 4~rr~D~e clo~ure ele~ent 2 ha~ been ~odified~ whereby hook po~ t 3 on 3~ ~y ~e po6itioned ~rogres6i~1y laterally ~n~a~d, a6 d~pict~d by alternate hook portion 31~ an~ altetnate hook ~ortion 31~ ~ovn in ~ee body, to~ard ar~
portion ~ of clo6ur~ elemen~ ~1 until hoo~ po~ion ~1 make6 contact ~ith ~aid ar~ po~tion 24 or i~ even de~lected ouewardly by ar~ ~ortion ~4. W~n ~he clo~ure fastening device i~ t~u~ constructed, the 6ucces~ively inward cu~vature of ar~l pottion 2g ~nd ~ook por~ion ~1 ~.o t~e positions ~hown by hoo~
portion ~1~ and book ~ortion ~ ræ~ultfi in gradually increa~ing the opening force reguired t~
separa~e and deocclud~ clo~ure elemen~. 2~ and clo6ure ele~en~ t has be~n f ound that ~cces~ively inwardly curYing ~ook por~ion 31 ~o the position depic~d by hook po~ion 31~ result6 in increasing ~he external opening o~c~ ~eguired in deoccl~ding closure ele~ent ~6 and clo&ure element ~1 from a force of about ~.S pound to a ~orc~ of about 2.0 ~ound6. ~t ~as al~o found t.~at ~ook por~ion ~1~ and hook po~ion 31~ re~ult in increa~ed inter~erence betwe~n t~e~e hook por~ions and hook portion ~5, ~eeeby re~uiring bending of the~e part~
during deocciu6ion of closure element 26 and closure elen~ent. 21. In operation, hook portion~ and ~ ct a6 a c~amp in maintaining occlusion of the closure device. ~y ~he ~an~ token, hook portion ~5 and hook portion ~0 provide a hinge action during deocclu~ion of,clo6ure ~lement. ~6 and closure ~lenlent ~I ~hereby hook portion ~S~ rotate6 with re~pect to hook portiorl 30 as ~hown in Fig. ~.
_ 13 ~
~'ig. ~-A i~ a cros~ ional ~ie~d of ~ e clo~ure fa6tening devi~e 6ho~n in Fig. ;~ b~t-~rein th~
~e~ond ~ clo6ure 6~1e~Rerlt i~ dif ied pur~uant.
p~" ts~ alt~rnate hook port.ion 31~. T~ typical phy6ical S dimen~ions of a clofiure ~stening device in accordance ~ditb rig. 3-A are a~ follo~
ay be f rom about~ O.U5(~ ~lo about 0.1 inch, pref erably abouS. 0.07~ inch;
2. ~ may be f ro~ about 0.040 to about o.()~o inc~l, preferably about. O.Ob7 in~h;
. C may b~ from ~bout 0.0~10 to about O.Ot~0 inch, pref erably abcus. 0.~60 in~
4 . 1? ~ay be f rom ab~ut 0,007 ~o ~I~OUt 0. 012 inc~, pre~erably abol~t. ~).00~ incb;
~ E may be from abou~. 0.008 ~o about o.o inch. pref erably about (). 01~ ch;
. F may b~ f rom ~bou~ 0 . 00~ t o about 0. ~15 inc~l, pree~bly about. U.l)13 inch;
~ . G may be f ro~n abo~t. 0.00~ ~o ahout O.OlS
inch, ~teferably ahcut O.vi2 inc~;
. H m~y be from about 0.00~ to about O.OlS
inch, preferably about 0.011 inch;
9. ~ may be from about ~.00'/ to atout 0.012 inch, pref ~rably about 0.00~ inch;
~- K ~l~ay be from abou~ ~.ooa to ahout O.OlS
inch, pref erably about 0.011 incb;
11. L may be ~rom about 0.00~ to about O.nlS
inch, pr~fel~ably abor~t 11.012 inch;
1;2 . M nlay h~ f ronl about 0 . 009 t o about 0 . OZ0 ~nch, pr~ferably about 1).01~ ~ncb;
r~ R mdy ~ froRI about ~.00} to atout. 00130 incJ~, pr~f ~rably about 0.10~ inch; ar,d ;
14 . ~ y be t rom about. O . 0~ to ~bout 0 .105 incll. pzet2rably abou~ 0.07~ in~h.
~6 indieated in ~`ig. 3~ repre~ent6 ~ne t~eigtll~ dime~a6ion s3f ~tle clo6ure f~enang a~Yice ~n an occluded po~ition ~ ~ea~ured f roril ttle apex porti~n ~f the f ~rst clo~ure ele~er~ to ~he ap~x portiC~D o ~he sec~nd ~lo~ure element~
~ repre~ent.s the height dil~en~ion of the second clo~ure element as mea~ured ~rom ~be apex portion of t~le ~econd ~losure element. to the tip of the second alm ~ortion of ~lle 6econd clo~ure element.
C represents tbe height dimen6ion ot th~
f ir~t. cl~sur~ el~enl~. a~ mea6ur~d f ~om ~tle ape~
portion of ~he fi~t. closure el~ment to ~he l~igi ess part of tl~e pr~file porti~n of the firs~ clo ure ~1 ement .
R represen~ tl~e vidt h dimensiorl c f ~he 6ecorld clo~ure element. a~ mea&ured ~om ~he widesl.
part of t.he ~Eir~t. ~rm portion of ~lle ~eco~.d elosure ~lement. t.o the wide~ part of the secon~ arm portion of t~e second clo~ure ele~en~.
5 repre~ent 6 the ~idth dimension of the ~irst closure element a~ measured between tbe ~ip~
o~ ~he outvardly facin~ hook portions of ~he fir closure element.
~ig. 4 i6 a cro s-6ectional vie~ of the clo~ure fastening device ~o~n in Fig. 2 in an occluded po~i~ion, in a partially deoccluded po6ition, and in a deoccluded position. It ~a~ been f oun~ t~at du~ing occlu6ion and deocclu6ion of tne clo6ure fa6tening device of ~his inven~ion, one or bot~ ot ~ne clo6ure elemen~ of th~ f~tening devic~
experience a gr~aua~ t.~i~ting o~ torquing oper~ion ~p~e~d ~ver ~ 6igni~ic~nt l~ngt~ of th~ ~lo~ur~ on ~it~er ~ide ~ the pcin~ o i~it.i~l forc~
app~ication. Tbe ~p~eading ac~ion of thi6 tsrque reduce~ ~t~e68 lev~ ther~by reduciDg ~orce.
During deocclu~ion of th~ fastening device, ~hi~
~.wi~t.ing or torquing operation con~inue~ until the hook por-lon~ ot ~e closure ele~ents ~ave di6engaged ~rom each o~er.
Fiq. 4 6ho~s in detail Bome of the op~a~ional 6tep6 during deocclu~ion of a clo~ure : ~c~ening deviee as de6cribed witb re~pect to ~ig. 3 ~erein the second clo6ure elemen~ i6 modified pur6uant to alte~nate ~oo~ portion 31~. ~ore ~pe~if ically, w~len 6aid clo~ure fast~ning d~vice is in the ~ccluded po6ition, hoo~ poEtion ~1~ Of closu~e elemsnt 2~ i6 in con~açt wi~ arm poction ~4 of closure element. ~1, os hook portion ~5 of clo6ure el~ment 21 i~ in contact wit~ ar~ por~ion ~9 of closure ~lement ~. Typically. ~or deocclusion of the clo~ure fastening ~evice, an ext~rnal release forse is exert.ed on hook po~ion 31~ and ar~ portion ~9 o closure elenlen~ , and on hook portion 25 and arm portion 24 ot clo~ure ele~ent 21, to cause relea6e of ~ook portion 31~ and ar~l portion 29 of clo~ure ele~ent 2b, from hook portion ZS and arm por~ion ~4 of clo~ure element 21. The afore-mentioned par~6 of the fastening device are rota~ed over an arc o~ about 35 to a position generally designated a~ A, as shown by tbe arro~ in Fiq. 4. 1~ order to obtain full re~ease o t~e closure elemen~ an~ de~ccSu~it~ of the ~as~ening device, rotation of the clo~ur2 ~lemellt~ i~
cont inued over ~ ~rc of ~etwee~ ~bout 100~ ~In~ 120~
to a positaorl generally de~gnaa~d a~ R ~i~own by ~he arro~ds in Fig. q. During t~a~ coh~inued rotation, at~ ~or~ion ;i~ ~ ana llooh l?c rl,ioJl ;25 ~ o~
slo6ure element. 21, di6engaq~ f ror~ kloo~ l?or~ion ~0 of clo~ure element ;~, while go~ating around tlook portio~ :~0 Gf closure ele-n~nt 2~ un~ he parts are ~epara~ed ron~ each othe~.
lf a closure fast.ening device i5 preferred requiring a 6maller arc of ro~ation re6ulting in earlier deo~clu~ion of the closure element6, then closure elemen~ 2~ ~nd clo~ur0 element 26 may be r~odif ied a6 described ~i~ espect to Fig. 5. In Fig. 5 i~ s~own the slo~u~e eler~ent~ de~cribed with rezpsc~ ~o Fig. ~ ~dith the ~olIowinq modif icati~n~
aving been made tS~ereto. More particularly, ~tle inside rad.iu6 of curva~ure o~ hook portion ~0 i~
de~reased. E)uting deocc~u6ion o the closure fastening de~ice, 3f tf~r hol~k portion ~1 and arn~
por~ion ~9 of closur~ element ~6 are released f ro tloo~ portion ;25 and arm portios~ 4 o:E closure elemen~ ;21, con~inued rotation of the closure element ~ re~ult.~ in ~looh portion ~o of slosur*
element ~ having a camming or leverage etfect upon arm portion 24 ~ and ~looh po~tion ;25~ of closure ele~nent ;~1 to provide releaLe o the~e parts at an arc of about 75. Ttle contac~ point hetween hook p~or~ion 3(~ o~ closure e}ement ;~6 and arm portion ;24 ot clo~ure element ;2~ i~ generally de~ignat.ed in . F~g. 5 a6 point L, and ttle contact ~oint between hook poction :~0 o~ closure ele~nent 26 and book _ 17 --port~on Z5 ~ o~ clo~ure el~men~ 21 i~ generally ~own tller~in a~ point ~q. It ~ a~ been ouna ~hat th~
aforeae~r~be~ ~losu~e oles~en~6 prov~de ~xoc~u~ion of the o~slud~d fastening ~v~c~ more ~u~c~lr by 5 requiring ~ les~e amount o~ ro~t~on of ttle ~losure olem~nt~ vithout ~f~eeing 9~Oa occlu~on.
~ t l~hould be not~d at this p~int that ~e aetion6 discu66ed and illu6~rated fs~r deocclu6ion ~pply in tt~e r~vers~ order to oc~ ion, ~hich re-enqage6 tl~e hook elements gorming tlle hinge 6tructure, relea&e6 tor~ionally tvi&ted element6 and, by fur~her ~ovement, r~-esta~ he~ the clamping ;~c~ion. Thi6 i~ preaic~ted upon port~on~
o~ ttle clo~ur~ being rnaintain~d in an cc~1uded posieion a~ tt~e ~erminal end~ of ~he~ cl~sure devic~. Such a condition exi6~6 ~ n a length of ~uch a clo6ure device i~ incorpora~ed ;n a plastic bag ~ving sellled ~id~ ed~e~.
Fig. 6 ili ~ cros~-~eç~ional view o~ another embodiment of ~he clo~ure fa6tening devi~e in accQrdance with t~i~ inYention in a deoccluded po~ltion. As ~ho~n therein, t~e clo~ure faseening device include~ a i~6t ~lexible clo6ure element 40 navinq a general om~ga ~ape, and co~pri6e6 a generally 1at or 61ightly ~r~ua~e apex portion ~1 and ~ profile portion extending ~ro~ t~e apex por~ion. T~e profile portion ~ompri6e~ two inwardly curved arm portions 42 and 42', re~pectively, wi~h arm portion~ ~ and 43~ outw~rdly extending ~rom 6aid inwardly curved arm portions, re~pectively, and ~th ~aid outwardly extending arm portion~
~erminat~ng ~n outw~rdly ~uYving ~oo~ ~orticn~ 4 , . .
~n~ , r~6pectiYely. The clo~ro ~Fa~t~ d~vie~
in~lude~ ~ ~acona f l~xible closuro ~lemerlt ~5 t~*~ing a generally fl~t or ~ïightly ~rcuate apex portion ~6 ~na a pro~ilR port:ion exterlding fro~D ~ai~ apex 5 portion. T~le ~ro~ pOrtioll of ~id ~econd elo~ure ele~ent cnmpris~s one in~ar~ly ~ur~ea arm port~on 47 terminating ~r an inwardly ~urv~d ~ook portion ~, and one qenerally s~raigl~t arm portion 49 extending in ~ gener~lly perpendi~ular direct~on from ~aid 10 apex portion.
Fig. 7 ie ~ cro66-6ectional YieW of th~
elosure fastening devic* de~cribea wi~h refipe~t to Fi~. 6, l~ut ~own ~erein in an occluded po~ition.
It can be seen f~ola Fig. 7 ttla~ erl the in6~ant 15 c~o~ur~ ~a6terling d~ice i6 i51 ~n occluded pQ6ition, arm portion 49 of closure elemen~ 4S ~ locat~d bet~e~n ana in c~nt;~ct with outwardly ex~ending arm portion~ 4~ and 43~ of closure element 40, and hook portion 44 of clo~ure element 40 i~ interlocked with hook por~ion 48 of clo6ure element ~5. It can al~o be ~een trom F~g. 7 tha~ aro portion 43 terminating in outwardly curving hook portion 44 is adapted to engage in ~ hinging consact ~i~ ~rm portion 47 terminating in in~ardly cur~ed hook portion 48, and arm portion ~9 i~ adapted to engage in a ~lamping contact with ~it.her arm portion 43 or arm portion 43', or both 3r~ portion 43 and arm portion ~3'. but in any event, wit~ at. lea6t on~ o 6aid arm portions. Wh2n thi6 ~106ure ~a6~enlng device is employed vith a ~on~ainer, hook portion ~ and arm portion q9 are preferably located toward ~ ou2~ide porrion of t~e container, and hook port~on ~S ~nd ~ook portion 4~ are loc~t~a to~ard ~e in~i~e -portio~ o~ th~ contai~r. ~en tbu~ locat~ on a ~on~3iner, ~he ~lo~use fa~teni~g ~evice o t~i~
~nYention ~to~ides ~ fas~eninQ devic~ w~
relati~ely ~y t~ deocclu~ ope~ f~o~ tbe out6ide of t~e cont~inerO ~u~ w~ie~ i~ relatively difficult to deocclude or open fro~ the in6ide vf the container. Accordin~ly, when thus employed on a container, the clo6ure fa6tening d~viee provide~
i~proved security to content~ ~tored in said container.
~ . 8 i6 ~ cro6s-~ectional ~ie~ o~ the slo6ure ta~tening devic~ ~hown in Fig. 7 in a : partially d~occluded po~ition sueh a6 during : 15 deocclu~ion of ~he ~astening device. tt may be seen from Fi~ a~ during deocclusion vf clo~ure element 45 3nd slo~ur~ element 40, arm portion~
and ~ o~ clo6ur~ eleme~ 40 fir~t separate from drm portion 4~ ot cl08ure ~le~nent ~s. A~ closure element 40 and ~losure element 45 are fur~er rotated with respect to each otb~r for ~e~aration~
hook portion 44 of closure element 40 will rotate around a~d then ~ away from ~ook ~ortion 48 of closufe ele~ent. 4S, tbereby sesulting in t~eir Eeparat ion and in th~ complete deooclusion Oe the clo~ure fa6t~ning device.
~ ome o~ the preferred cloGure fas~ening de~ices of this invention ~ere evaludted for opening loads fo~ comparison with 6ever~1 commercial pla~tic container product~ having a ~losure fastening device. ~n ~11 th~ evaluations, ea~h occluded clo6~re a~ening device was cut into a 6iX incb Z77~
long 6~f~ple. Th~ slo6ure ~a~tening device za~ple6 ~ere t.e6te~ by att~cl~irl~ a ~i~c~ of one inch ~ide ~cotcl~ t,ape doubled over to grip the in~de ~nd/or ou~ide flan~e portior;s o~ ttle fa~tening ae~rice.
Eac21 6ample wa6 ~e~ted indepznd~ntly a6 de6cribed her~in. Ttle Male portion o~ the clo~ure fa6tening device ~,ras ~ounted in t~le upper ja~ and ~he f emale ~ortion ~ the clo6ure fa6tening device ~as mounted i t~e lower ja~d, o~ an ln6tEon63 ten~ile te6ter.
T~e force required t.o deocclude the elosure 2stening devic~ ~a~ recorded on a 6trip chart record~r 3~ tbe ~aximum forc~ regi6tered. ~be average valu~ ~da~ li6ted a~ the average o~ f ive te ~
6peci~en~ and i~ ~a~ recorded a6 eelea6e force. Tlle jaw 6epara~ion ~deoGcl~ion) rate wa~ za inclles per ~inut~ an~ ~h~ ull ~cale lsad ~a6 2U po-und~. Each of 5 identical ~ample~ was reoccluded and retes~ed f~r a t~tal of S ~o~ts. ~he v~lue reported was ttlus he average of 25 te~t6 for each 6anlple.
~rhe ~n6-ron instrument. ~a& a ten~ile ~ester Model No. 1130. u~iing a ~8~ load cell wi~tl a zero to 20 pound range. Tbe ~n~tror~ t~ter i~ initially calibrated in the Sollo~ing manner. The pen and c~art recorder are turned on. The zero but~on i6 Z5 pres6ed and held, and the zero adju~t knob i~
po6itioned for ~ 0.00 reading on the re~order. The z~ro b~tton i~ then released. ~he range sw~tc~ i~
~hen turned to t~e setting o~ 1 o~ itfi ~, 2. 5, 10, Z~ 6cale. The coar~e balance control i8 turned 60 tnat if t~e ~en is all the w~y o~er to th~ le~t, it 6t'are6 cominq towards xero on ~he right. T~e coarse balance control i~ le~t as thi6 position. T~en t~e f in~ balance cont rol i6 ~url~aed 60 ~haf, ~b~ ~en i~
a se~ting ot 0.00. 1~ 20 pound ~deight i~ ~lac~a ia~
~he upper jabl of ~ lle tn6tron instrument. ~n~ tne calibra~ion control i~ adiucted for ~ fu~l-scal@
recorder readis~9. A~t~r re~oving ~ weigh~, the recorder 6hould ag~in read 0.00. The zero bu~ton i~
pre~ed and held, and ~he rccorder ~hould again read V.~O.
5ample 1 repre~ent6 a ~lo~ure f astening device employed with a container available from Dow Chemi~al Company, ~qidland, Mictligan under the Tradename ZlPLOC0 Tt~e closure f~stening device :is believed to S~av~ bee~a made vith lo~ den~ity polye~ylene ~aving a den6ity of about 0.9;21 grasns p~r cubic centimeter.
~ample ;~ repre~ent~ a ~o~re IEa6tenirl~
device employed wit~l a cvnt~iner available f ron, Dow emical Company, Midland, Michi~,aJl under the t radename ZIPLOCG~ Microf reez .
~ample 3 repre~ents a olo~ure fas~ening device prcduced by Uni~n Carbide Corpora~ ion and con/merci~lly available ~ittl a container identif ied as SNAP LOCK~. The closure f ~stening device was made ~ith low den~ity polye~hylene, that is. having a density of about 0.923 grams per oubic centimeter.
~ample 4 ~epre6ent6 a clo~ure fastening device prepare~ in accordance ~ith ~his invention and a6 desccibed ~erein vith respect to Fig. 3, wherein the second 5~e~i~e clo6ure element was modifi~d pur6uant to al~ernate ~ook portion 31'.
.. Sample 5 represents a clo~ure tastening device prepared in accordance with this in~ention ~; .
~nd ~ de~c~ her~in with re6p~c~ t.o Pig. 3, wherein th~ ~cond i-ht~H~}~ c10~ure element va~
~odified ~ur~uant to alternat~ hook port.ion 31~.
Sh~ cl~sure ~astening aevices of ~a~ple and ~ample 5 ~ere ~ade ~ith 3 the~op~a~tic re6in co~eosi~ion compri6ing ~bcu~ p~rcent ~y weigbt o~
polypropylene ~omopolymer, about. ~S porcent by ~eight of an ethylene-propylene-diens monomer ela6tomer, and about 1 peccent by weig~t of ~ ~lip agent, all ~eig~t percentages b~ing based on the ~eig~t of t~e fastening device.
Bot~ ext~rnal relea6e forc@~ and internal relea6e force~ ~ere recorded. ~y external ~elea~e forcefi is ~e~nt the torce6 required to deocclude the clo6ure fa~tening device fsom ~e ou~ide portion of a con~ainer. By in~ernal release force~ i6 mean~
: t~e force~ reguired to deo~clud~ the closure ~a~ening deviee fr~m ~he in6ide portion of a ; container;
The ~e~t reEul~s are giveu below in Table 1.
Relea~e Force ~lbsl Force R~io ~amPle Internal Ext~rnal (-Interna~ terndl) 1 3.8 1.5 2~5:1.0 2 3.3 1.6 2.1~
3 4.5 ~S 1.8:1.0 4 10.~ ~.5 Zo.0:1.0 S 12.~ 2~0 ~.0:1.0 ;
~rom ~e above re6ult~ in Table 1. it can b~ 6een t~at tbe closure fastenin~ device6 of t~is inYention provide in~ernal release re6i6tance forces ; ~
~ Z3 --whic)l ar~ betw~en ~o and t.bre~ t~m~ a~ hig~ al~
~bo~e o ~oR~e comn~e~cial clo~ure fa~tenin~ devicefi, -~bile manipula~iv~ ext.erna~ d~occl~sion ~orce6 ~ay ~e ~eld to ~a ~ini~flun~. ~h~reby providin~ ea~y and 51en~ le deb6clu&ion of tt~ lo~ur~ f ast ening device~
o this invent ion.
~n ~ddi~.ios~ to it~ u6e wi~b a container, the closure fa~tening device ~an be u~ed to electrically in6ulate ~ire lead~ or bind toge~ ~er group of ~ire6. ~he clo6urlla device can al60 be used a~ a f lexible ~tr~w b~cau6e æ qood Ij~al at the engaged 6urface i~ pos~ible and tt~e compartment def ine~ by the ~emen~ provides a pas6a~eway ~ ich does not co~lap~e vhel~ ~he clo~ure fa6~ening device ~; 15 i ~ bent .
Generally" ~Ihe clo~ure devi~e of the invention C~ e nl~n~f as:~ured in a variety of f osms to ~uit ~l~e intenaed u6e. Ir~ addition t.o ~l~e embodiment ~ 6bown ~lerein t~e element~ can be po~itioned on oppo~ite side~ of a f ilm. Suc~ an embodill~ent ~ol~ld be suitea for enw~apping an object or ~ collect ion o~E ob ject6 suc~ a6 wires .
G~nerally. ~he elements on ~ filn~ ~ho-~ld be parall~l to ~ach otner but thi~ wou~d depend o~ the intended u~.
Al~hough the ~re~ent invention has been described and set fvrth in ~ome detail, it should ~e fur~hel under~tood that th~ ~ame is ~uscep~ible to change6, modification~ and Yariation~ wi~.hout departing fron~ t~e 6cope and 6pirit of the invention as set ~orlh in t~ appended claim~. ~uch c~anqes, modification~ ~nd ~ariations are wit~in the 6copæ of thi6 inventioll.
SUPPLEMENTARY DI SCLOSURE
In selecting a resin composition for the profile portions and the flange portions of a closure fastening device which ls employed on a bag or container or use in a high temperature environment, such as in a microwave oven or boiling water, the resin composition must meet several criteria. These criteria include high heat resistance, relatively low flexural modulus at low temperatures, acceptable extrusion characteristics, and convertibility of the film into end products such as bags or containers. High heat resistance is necessary because when the bag or container is equipped with the interlocking closure ~astening device and is used in a microwave oven where-food temperatures can reach about 300F., or in bailing water where the temperature of the cooking vessel can exceed 212F., the closure ~astening device must retain proper occlusion and deocclusion forces. The resin composition must also be flexible at low temperatures because such bags or containers are often used in a freezer for food storage, and when removed from the freezer, the closure fastening device must be sufficiently flexible so that the - 23a -,~,, ~m~
bags or containers can be easily opened when such is desired as to remove ood therefrom. In addition, the resin composition for the interlocking closure fastening device must have acceptable extrusion characteristics so that it can be easily processed in production and make a reliable, reproducible product.
In the extrusion of such interlocking closure fastening devices, it is desirable to extrude closure elements having base and profile portions onto a common flange portion, separate the closure elements, and then attach the closure elements to the bags or containers. This operation presents a ~roblem in the closure extrusion phase because some of the closure elements are near the outer edges of the flange portion which is an area conducive to "neck-in" of the resin material.
"Neck-in" may be described as a decrease in an article's dimensions transverse to the take-off or elongation direction of the article. In such event, the edges of the flange portion exiting from the die will shrink toward the center of the flange portion in a curved path. When the edge of a flange portion "necks-in" toward the center of the flange portion, - 23b -~ ~76~
a closure element positioned near the flange edge will travel with the edge of the flange portion.
The result is that the closure element is not extruded in a straight line as desired, but follows the curved path of the edge of the flange portion.
This result causes distortion of the closure element due to the two dimensional path followed by the closure element. Therefore, in choosing a resin composition for the flange portion of a closure fastening device as described herein, it is highly desirable to employ a resin composition that suffers a minimum of "neck-in" so that the closure elements extruded near the outer edges of the flange portion travel in as close to a straight line as possible which minimizes closure distortion.
On the other hand, when choosing a resin composition for the closure elements, i.e., the base and profile portions, of the interlocking closure fastening device, the main concern is to employ a composition that will retain the intricate profile shapes of the closure elements during the extrusion process and during the cooling process. This concern is more important than limiting "neck-in"
tendencies of the resin composition.
- 23c -As set forth previously, the first and second closure elements of the fastening device of the invention are adapted to engage and disengage by means of either a straddling or an overlappiny type of occlusion. A straddling type of occlusion occurs when one arm portion of the second closure element is lodged between the two arm portions of the first closure element, while the other arm portion of the second closure element is outside one of the arm portions of the first closure element when the closure device is occluded. An overlapping type of occlusion occurs when both arm portions of the first closure element are within, or inside of, both arm portions of the second closure element when the closure device is occluded.
During deocclusion of the aforedescribed closure fastening devices, one closure element must be rotated between about 30 degrees to about ~0 degrees with respect to the other closure element to disengage the arm portions thereof located closer to the exterior portion of a container, and urther rotated between about 70 degrees to about 120 degrees with respect to the other closure element to - 23d -~, disengage the arm portions thereof located closer to the interior portion of the container.
In the preferred mode, the closure fastening device of this invention is made from a polyprop~lene copolymer, or a blend selected from (a) a polypropylene copolymer and a polypropylene homopolymer, (b) a polypropylene copolymer and a polybutene copolymer, ~c) a polypropylene copolymer and an elastomer, and (d) mixtures of (a~, (b), and (c). More specifically, it is preferred that the closure elements comprise a poly(propylene-ethylene) copolymer having an ethylene content of less than about 5 percent by weight of the copolymer because too much ethylene will lower the melting point of the copolymer and cause distortion of the closure profile during extrusion, and between about 100 ppm and about 2000 ppm of a slip agent based on the weight of the polypropylene copolymer. The slip agent is preferably selected from fatty acid amides such as erucamide. Suitable alternative compositions for the closure elements comprise a blend of (a) from about 85 to about 95 percent by weight of polypropylene homopolymer and from about 5 to about 15 percent by weight, preferably about 10 - 23e -percent by weight, of a poly-l-butene copolymer containing up to about 5 percent by weight of ethylene; ~b) from about 85 ~o about 95 percent by weight of polypropylene homopolymer and from about 5 to about 15 percent by weight, preferably about lQ
percent by weight, of ethylene-propylene-diene monomer elastomer; (c) from about 85 to about 95 percent by weight of polypropylene homopolymer and from about 5 to about 15 percent by weight, preferably about 10 percent by weight, of ethylene-methyl acrylate copolymer; (d) from about 10 to about 50 percent by weight of polypropylene homopolymer and from about 50 to about 90 percent by weight, preferably about 70 p~rcent by weight, of a poly~propylene-ethylene) copolymer selected from the group of poly~propylene-ethylene) copolymers having a melt flow rate of between about 1.5 and about 8, and preferably, about 7 grams/10 minutes as determined by ASTM test method D-1238, Condition "L`', and a flexural modulus of between about 100,000 and about 132,000 psi or an MPa value of between about 690 and about 924 as determined by ASTM test method D-790; and (e) from about 85 to about 95 percent by weight of poly(propylene-ethylene) - 23f -copolymer and from about 5 to about 15 percent by weight, preferably about 10 percent by weigh~, of a copolymer ~elected from the group consisting of (1) a poly-l-butene copolymer con~aining up to about 5 percent by weight of ethylene; (2) an e~hylene-propylene-diene monomer elastomer; and (3) an ethyle~e-methyl acrylate copolymer. As i~ the best mode compositions employed to make the closure fastening devices herein, all of the alternative compositions preferably contain between about 100 ppm and about 2000 ppm of a slip agent ~elected from fatty acid amides based on the weight of the blends.
The foregoing resin materials are all commercially available. For example, the poly(prop~lene-e~hylene) copolymer material may ~e obtained from Himont Inc., Wilmington, DE under the trade~ark Pro-Fax~ SA-861; the polypropylene homopolymer may be obtained from Shell Chemical Company under the trademark Shell Polypropylene 5~25; the poly-l-butene copolymer containing up to abaut 5 percent by weight of ethylene may ~e obtained from Shell Chemical Company under the trade~ark Shell Polybutylene 864~; the ethylene-propylene-diene monomer elastomer may be . . ~
obtained from Uniroyal Chemical, Naugatuck, Ct.
under the tradema~k Royalene IM 7565 a~ a 65/35 weight blend o~ the elastomer ~high density polyethylene; the ethylene-methyl acrylate copolymer is available from ~ulf Oil Chemi~als Company under ~he trademark PE 2205; the poly(propylene-ethylene) copolymer may also be obtained from Cosden Oil Company under the trademarks Dypro W-431 and Dypro K-122, and from Himont Inc., Wilmington, DE under the tr~de~ark Pro-Fax~ ~A-752.
It has been found that when in~erlocking closure elements are made from the for~going resin compositions, the profile portions of the closure ;~ elemen~s retain their shapes and have a low flexural modlllus under the extreme temperature conditions thereby ~eeting the aforementioned criteria for an interlocking closure fastening device. The poly(propylene-ethylene) ~opolymer enhances the extrudability of the closure elements because they retain their shapes better during manufacture than when made from other materials.
When ~he closure device of the inventi~n is connected to a container, it is preferred that the closure device be manufactured with flanges on each - 23h -.
of the closure elements so that the flanges can be used to connect the closure elements to the container or to a film to be formed into a container. The flanges of the closure device may be made from a thermoplastic material selected from the group consisting of a polypropylene homopolymer, a poly-l-butene copolymer, an ethylene-propylene-diene monomer elastomer, and an ethylene-methyl acrylate copolymer. However, in the best mode of this invention, the flanges of the closure device are made from a blend of a polypropylene homopolymer and a poly-l-butene copolymer. More specifically, it is preferred that the flanges comprise from about 85 to about 95 percent by weight of polypropylene homopolymer and from about 5 to about 15 percent by weight of poly-l- butene copolymer containing up to about 5 percent by weight of ethylene. More preferably, the flanges comprise about 90 percent by weight of polypropylene homopolymer and about 10 percent by weight of poly-l-butene copolymer containing up to about 5 percent by weight of ethylene. Less preferred, but suitable, alternative material compositions for the flanges comprise ~a) From about 85 to about 9S percent by weight of .
- 23i -~7~
polypropylene homopolymer and from about 5 to about 15 percent by weight of ethylene-prGpylene-diene monomer elastomer; or (b3 from about 85 to about 95 percent by weight of polypropylene homopolymer and from about 5 to about 15 percent by weight of ethylene-methyl acrylate ~opolymer, or (c) mixtures of (a) and (b).
The foregoing resin materials are commercially available. For example, the polypropylene homopolymer material may ~e obtained from Shell Chemical Company under the tradema~k Shell Polypropylene 5225; ~he poly-l-butene copol~mer containing up to about 5 percent by weight of ethylene m~y be obtained from Shell Chemical Company under the trademark Shell Polybutylene 8640;
the ethylene-propylene-diene monomer elastomer may be obtained from Uniroyal Chemical, Naugatuckt Ct., under the trademark Royalene IM 7565 as a 65~35 weight blen~ ~f ~he elastomer/high density polyethylene; and ~he ethylene-methyl acrylate copolymer i~ available from Gulf Oil Chemicals Company under the trademark PE 2205.
It has been found that when the flange portions of the interlocking closure fastening - 23j -device of this invention are made from the foregoing resin compositions, distortion of the closure elements is significantly reduced since the flange portions of the closure device experience minimal neck-in during extrusion. It has been found that the polypropylene homopolymer reduces neck-in of the flange portions during extrusion, and that the presence of poly-l-butene reduces the flexural modulus of the polypropylene homopolymer making the device suitable for use after storage in a freezer.
In preferred practice, the flanges and the closure elements are coextruded, however, the flanges and the closure elements may be extruded separately and then attached to each other by conventional means.
An important aspect of the closure fastening device of this invention is its ability to function properly when made with materials which are less flexible than those employed in the prior art.
That is, prior art closures are generally made of polyethylene having a low flexural modulus, and engage and disengage by a flexing action, whereas the instant closures are different there~rom in that khey function by a hinging action or operation since they are made from high temperature resistant resin - 23k -materials having high flexural modulus properties, i.e., at least about 50,000 psi.
Typical physical dimensions of a closure fastening device in accordance with Fig. 3-A have been yiven previously on pages 13-14. Preferred physical dimensions of the closure astening device in question are as follows.
A may be from about 0.050 to about 0.140 inch, pref0rably about 0.120 inch.
B may be from about 0.040 to about 0.100 inch, preferably about 0.080 inch.
C may be from about 0.040 to about 0.100 inch, preferably about 0.080 inch.
D may be from about 0.007 to abou~ 0.015 inch, preferably about O.OOg inch.
E may be from about 0.008 to about 0.015 inch, preerably about 0.011 inch.
F may be from about 0.008 to about 0.015 inch, preerably about 0.013 inch.
G may be from about 0.008 to about 0.015 inch, preferably about 0.012 inch.
H may be from about 0.008 to about 0.015 inch, preferably about 0.0l.1 inch.
. . .
I may be from about 0 . û07 to about 0 . ûl~
inch, preferably about 0. OOB inch.
K may be from about 0 . 008 o a3bout 0 . 015 inch, preferably about 0 . 011 inch .
L may be from about 0 ~ 008 to about 0 . 015 inch, preferably about 0.012 inch.
M may be from about O.Oû9 to about 0.020 inch, preferably about 0 . 017 inch.
R may be from about 0.050 to about 0.240 inch, preferably about 0.140 in~h.
S may be from about 0.034 to about 0.224 inch, preferably about 0.116 irlch.
~ ine resin materials were evaluated for use in the closure f astening devices of this intrention .
These mat:eri;als were evaluated to eompare polypropylene materials having a high meltis~g point and a high ~lexural modulus to measure closure deocclusion forces required and ~heir thermal stability. Resin material no. 1 (Shell 5225, trademark of Shell Chemical Company) was a polypropy-lene homopolymer having a flexural modulus of about 190,000 psi, a flow index of about 0.6 gram/10 minutes, and a melting point of about 325F. Resin material no. 2 (Shell DX 6020, trademark of Shell Chemical Company) was a poly(propy~ene-ethylene) random copo~ymer having a flexural modulus of about 110,000, - 23m -~776~
a flow index of about 2.0 grams/10 minutes, and a melting point of at least 270 F. Resin material no. 3 (Cosden Dypro K-122, trademark of Cosden Oil Company) was a poly(propylene-ethylene) random copolymer having a flexural modulus of about 120,000, a melt index of about 1.5 grams/10 minutes, and a melting point of about 297 F. Resin material no. 4 (Cosden Dypro W-431, trademark of Cosden Oil Company) was a polytpropylene-ethylene) random copolymer having a flow index of about 3.0 grams/10 minutes, and a melting point of about 275 F.
Resin material no.5 was a poly(propylene-ethylene) random copolymer having a flexural modulus of about 120,000 and a flow index of about 2.0 grams/10 minutes.
~esin material no. 6 was a poly(propylene-ethylene) random copolymer having a flexural modulus of about 120,000, a flow index of about 1.0 gram/10 minutes, and a melting point of about 330 F. Resin material no. 7 (Cosden Dypro X-7350, trademark of Cosden Oil Company) was a poly(propylene-ethylene) random copolymer having a flexural modulus of about 75,000, a flow index of about 1.5 grams/10 minutes, and a melting point of about 264 F. Resin material no. 8 (Himont SA-752, trademark oE
Himont Inc.) was a poly(propylene-ethylene) - 23n random copolymer having a flexural modulus of about 132,000, a flow index of about 3~0 grams/10 minutes, and a melting point of about 275F. Resin material no.
9 (Himont SA-861, trademark of Himont Inc.) was a polypropylene block copolymer having a flexural modulus of about 120,000 psi, a flow index of about 7.0 grams/
lOminutes, and a melting point of about 315F.
After extrusion into closure fastening devices haviny the structural confis3uration of Fig. 2, the resin materials were evaluated for opening forces required from the outside and from the inside of a container, and als~ for peel force.
Peel force is a measure of the f~rce required to pull the two closure elements apart after they have been partially deoccluded to form an initial opening in the closure device. A high peel force is desirable to enable opening a container only t~ a æmal 1 exten~ . Such a 6mal 1 opening can act as a vent to either s aueeze ~he air out of the container before freezing, or let ~eam escape from the container during cooking. The peel force is measured by placing a partially opened closure device in the jaw~ of a tensile tester available from In~tron Corp., Canton, Mass., with the first ~ 230 --closure element in one jaw and the second closure element in the other jaw. The ~ensile tester pulls the two closure elements apart at a speed of about 20 inches per minute, and the peel force of the closure device is measured. These results are tabulated in Table 2 which follows. In addition, the resin materials were evaluated for heat resistance in a boiling water test, as well as for shrinkage and general appearance. In this test, six-inch long samples are placed in boiling water for about 30 minutes. These results are tabulated in Table 3 which follows. The resin materials were further evaluated for heat resistance in a hot oil bath test at 250F and 300F and shrinkage measurements were taken. In this test, seven-inch long samples are placed in the hot oil batch for about three minutes. The results of this test are shown in Table 4 which follows.
- 23p -`~;~
Table 2 Opening Forces, Resin Pounds, Mean Peel Force, Material Outside Inside Grams, Mean 1 2.0 12.0 70 2 4.2 4.6 52 3 7.9 3.0 73 4 2.1 11.3 32 ~.9 3.5 14 6 1.7 5.8 27 7 3.6 9.1 67 8 1,2 12.3 14 9 1.3 9.5 19 Table 3 ,,:
: Water Boil Test Resin Mate.rial Shrin~aqe* Appearance 1 0 by 0 Good 2 0 by 0 Good-3 0 by 1 Good 4 8 by 4 Good Not tested Not tested 6 5 by 1 Good 7 0 by 1 Poor ~ Not tested Not tested 9 0 by 0 Small waves in flange portion Shrinkage values are dimensions in length by width measured in 64thS of one inch.
- 23q -Table 4 Hot Oil Bath Test Resin ~hrinkaqe*
Material 250F 300F
1 4.~ 8.7 2 0.0 31.0 3 2.7 24.0 4 4.7 destroyed not ~ested not tested 6 4.0 ~.5 7 19.5 d stroyed 8 2.7 10.0 9 0.0 15.~
Microfreeze ~,o(l) 12.3(2) * Shrinkage values are length dimensions only measured in 64thS o~ one inch.
(1) The closu~e profiles sealed ~oqether.
(2) The closure profiles ~nd flange por~ions s~aled together.
(3) Trademark of Dow Chemical Company.
From the preceding test results, it was determined that resin materials 1, 6, and 9 unexpectedly possessed preferred properties in terms of closure opening forces and thermal stability required for the closure fastening devices of this invention. In addition, it was found that these resin materials had excellent extrudability, and also laminated well to the film material employed to make the food containers.
- 23r -1~
It has further been found that the closure fastening devices of this invention are particularly suitable for u~e with a container for food, wherein the container is employ~d to store food in a freezer, and subsequently placed in a cooking vessel, ~uch as a pot containing boiling water, or placed in a microwave oven for cooking the ~ood. Significantly, the closure fastening devices of this invention have high resistance to heat, while possessing ~atisfactory low temperature flexing properties.
Further, 60me of the preferred closure fastening devices of this invention were evaluated or e~d-use application along with a commercial container available from Dow Chemical Company, Midlan~, Michigan, un~er the tra~e~ark Ziploc I Microfreeze bags. The closure fast~ning devices o this invention were laminat~d to a multilayer film to provide a series of containers. The containers were evaluated in a microwave oven by placing food in ~he containers and cooking the food for a time sufficient to raise the temperature of the food to about 300~F.
Generally, ~pea~ing, it was found that the closure fa~tening devices of this invention w~re still intact when the containers were remoYed from the microwave - 23s -7~
oven and had only minimal distortion However, the closure fastening device of the Ziploc (trademark of Dow Chemical Company) Microfreeze bag, believed tu be made from low density polyethylene having a melting point of about 220 F.~ melted during this cooking test even though food did not contact the closure fastening device. The Ziploc closure device was not functional after the cooking test.
In addition, the following closure fastening device compositions were evaluated. Test composition No. 1 consisted of a blend of about 90 parts by weight of a polypropylene homopolymer ~Shell 5225, trademark of Shell Chemical Company~ having a flexural modulus of about 190,000 psi~ a melt index of about 0.6 gram/10 minutes, and a melting point of about 325 F~ and about 10 parts by weight of a polybutylene copolymer containing up to about 5 percent by weight of ethylene (Shell 8640, trademark of Shell Chemical Company) wherein the blend was employed for the flange protion of the closure device. The profile portion of the closure device was made with a polytpropylene-ethylene) copolymer (Himont SA-861, trademark of Shell Chemical Company) having a melt flow rate of about 7 decigrams/minute , and a tensile modulus of between 90,000 and 95,000 psi. In addition, the poly~propylene-ethylene) copolymer - 23t -7'7Ei~3 employed to make the profile portion contained about 800 ppm of erucamide as a slip agent. This combination of resin materials was found to have good temperature tolerance at both hot and cold temperatures, as well as providing satisfactory opening and peel forces to the instant closure fastening devices.
- 23u -
said first closure element having a general omega shape, comprising an apex portion and a profile portion extending from said apex portion, said profile portion comprising two inwardly curved arm portions terminating in two outwardly facing hook portions; said second closure element comprising an apex portion and a profile portion extending from said apex portion, said profile portion comprising first and second arm portions, wherein said first arm portions terminates in an inwardly curved hook portion adapted to engage in a hinging contact with one arm portion of said first closure element, and said second arm portion is adapted to engage in a clamping contact with one arm portion of said first closure element.
said first closure element having a general omega shape, comprising an apex portion and a profile portion extending from said apex portion, said profile portion comprising two inwardly curved arm portions terminating in two outwardly facing hook portions; said second closure element comprising an apex portion and a profile portion extending from said apex portion, said profile portion comprising generally parallel first and second arm portions, wherein said first arm portion terminates in an inwardly curved hook portion adapted to engage in a hinging contact with one arm portion of said first closure element, and said second arm portion terminates in an outwardly extending portion adapted to engage in a clamping contact with one arm portion of said first closure element.
said first closure element having a general omega shape, comprising an apex portion and a profile portion extending from said apex portion, said profile portion comprising two inwardly curved arm portions terminating in two outwardly facing hook portions; said second closure element comprising an apex portion and a profile portion extending from said apex portion, said profile portion comprising curved first and second arm protions, wherein said first arm portion terminates in an inwardly curved hook portion adapted to engage in a hinging contact with one arm portion of said first closure element, and said second arm portion terminates in an outwardly curved portion adapted to engage in a clamping contact with one arm portion of said first closure element.
said first closure element having a general omega shape, comprising an apex portion and a profile portion extending from said apex portion, said profile portion comprising two inwardly curved arm portions, an outwardly extending arm portion from each of said inwardly curved arm portions, each of said outwardly extending arm portions terminating in an outwardly curved hook portion; said second closure element comprising an apex portion and a profile portion extending from said apex portion, said profile portion comprising first and second arm portions, wherein said first arm portion terminates in an inwardly curved hook portion adapted to engage in a hinging contact with one arm portion of said first closure element, and said second arm portion extends in a generally perpendicular direction from said apex portion and is adapted to engage in a clamping contact with at least one arm portion of said first closure element.
Claims Supported by Supplementary Disclosure
- 36c -
about 5 to about 15 percent by weight of a material selected from the group consisting of ethylene-propylene-diene monomer elastomer, ethylene-methyl acrylate copolymer, and mixtures thereof, based on the weight of said flange portions.
- 36e -
- 36f -
- 36g -
Priority Applications (2)
|Application Number||Priority Date||Filing Date||Title|
|Publication Number||Publication Date|
|CA1277640C true CA1277640C (en)||1990-12-11|
Family Applications (1)
|Application Number||Title||Priority Date||Filing Date|
|CA 471202 Expired - Lifetime CA1277640C (en)||1983-12-30||1984-12-28||Single hinge interlocking closure profile configuration|
Country Status (7)
|EP (1)||EP0150510B1 (en)|
|JP (1)||JPS61500960A (en)|
|CA (1)||CA1277640C (en)|
|DE (1)||DE3474538D1 (en)|
|DK (1)||DK386885D0 (en)|
|FI (1)||FI853306L (en)|
|WO (1)||WO1985003055A1 (en)|
Families Citing this family (2)
|Publication number||Priority date||Publication date||Assignee||Title|
|US4922588A (en) *||1983-12-30||1990-05-08||First Brands Corporation||Single hinge interlocking closure profile configuration|
|US4710968A (en) *||1985-09-11||1987-12-01||First Brands Corporation||Trident interlocking closure profile configuration|
Family Cites Families (3)
|Publication number||Priority date||Publication date||Assignee||Title|
|US3416585A (en) *||1965-10-24||1968-12-17||Minigrip Inc||Flexible container having interlocking rib and groover closure elements|
|US4212337A (en) *||1978-03-31||1980-07-15||Union Carbide Corporation||Closure fastening device|
|DE2948914A1 (en) *||1978-12-22||1980-06-26||Union Carbide Corp||Container|
Also Published As
|Publication number||Publication date||Type|
|US4194039A (en)||Multi-layer polyolefin shrink film|
|US4875587A (en)||Easy open shrinkable laminate|
|US4944409A (en)||Easy open package|
|US4784863A (en)||Meat product package containing an inner layer of starch/ethylene vinyl acetate|
|US3682767A (en)||Ethylene copolymer blend for liquid packaging film|
|US4638913A (en)||Multiply package having delaminating easy open seal|
|US4865902A (en)||Multilayered polyolefin high shrinkage, low-shrink force shrink film|
|US4539263A (en)||Blends of ionomer with propylene copolymer and articles|
|US5460861A (en)||Multilayer stretch/shrink film|
|US4550141A (en)||Blends of ionomer with propylene copolymer|
|US5527608A (en)||Oriented multilayer heat sealable packaging film capable of withstanding high altitude effects|
|US6244748B1 (en)||Plastic package with fastener|
|US4653640A (en)||Packaging materials for photosensitive materials and process for producing same|
|US5629059A (en)||Multi-layer packaging film and receptacles made therefrom|
|US4665130A (en)||Packaging film and sheet capable of forming peelable seals with good optics|
|US5061532A (en)||Multilayer structure and easily openable container and lid|
|US4196240A (en)||Heat shrinkable multilayer packaging film of blended copolymers and elastomers|
|US4617241A (en)||Linear polyethylene stretch/shrink films|
|US4629640A (en)||Packaging materials for photosensitive materials|
|US4291092A (en)||Heat sealable packaging film comprising propylene polymer substrate and a surface layer blend of ethylene copolymer and propylene copolymer|
|US5852152A (en)||Packaging and wrapping film|
|US6777046B1 (en)||Puncture resistant, high shrink films, blends, and process|
|US6476137B1 (en)||Ternary polymer blend, the film containing it, and the easy-to-open package made therewith|
|US4188350A (en)||Olefin polymer blends and films therefrom|
|US5626929A (en)||Peelable and heat sealable lidstock material for plastic containers|