Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Baokground of the Invention
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Thi~ invention relate~ to cont~iner clo~ure~. It h~
partlculnr applica~ion to crown oap~ or bottle~,~ mo~t e~peci~lly
to beQr bottle crown~.
A beer conta~ner o~ p~cXage mus~ prot~t the fl~vor of
the beer duri"~ tran~poxt ~nd a~orage o~ ~h~ beer. It mu~t
exclude all oxygen. It mu~t not oontain any mate~ial~ which CAn
be extractad by the beer,~ and ~onv~r~ely it muRt not ~aavenge the
~lavor~nt~ n~turally oaouxring in the beer~ Altho~gh bottled
beer h~s popularLy been re~rded a~ well protected~ ~r~w~r~ have
long known ~hat bot~le crown~ have not provided altoqether
adequate pro~ectiOn of ~h~ ~eer. The proble~ has been found ~o
be largely in tho plastic crown liner. A d~us~ion of the
proble~s a~ociat~d with polymerle pack~gin~ material~ ( inaluding
c~own line~s) in th~ beer induRtry i8 co~tained ln a pap~r
entitled "Packaglng M~terial~ and Bee~ Qua~ity" by ~r.,W.A.
Ha~dw~ok, Jr., appe~rln~ a~ chapter 23 in ~r Pac~aginy: A
Manual ~o~ the 8r~wing an~ BeVe~ge Indu~tri~, edited by Harold
M. Broderick (Madi~on, Wiscon~ln.l 1982).
The mo~ co~on crow~ liner ma~erl~ polyvlnyl
chlorlde (PVC), containing d1octylphthal~te ~ a pla~ticizer, an~
a calcium or zlnc ste~rat~ ant~oxldan~, ~hi~ ~aterial ~ven~e~
30me of th~ ~lavor-giving e~ters ln beo~ and fre~uently contain~
ex~r~ctable impurities.
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The PVC llner i8 applied elthe~ ~8 ~ creamy pla~ti~ol
and spr~ad by ~p~nnlng o ~olding,l or el~e by melting a powde~ed
plasti~ol in ~n extruder ~nd extruding the ~olten materl~1 into
the crown sh~ll, In the latter p~oaeRs,l a ~ampin~ tool may be
UBed to fo~m t~e liner. The llner ~ ~o~etime~ applied ~ a
die-cut ~ilm and melted to the crown ~h~ll in eitu. In any o~
these proceq~es, it 1~ important to control tha temperature
care~ully to drive off all volat~le material~ without damag~ng
the crow~ ~hell or the polymer. The crown liner i~ om~time~
foAmed to give lt more re~ilience,~ but both ~he ioamln~ ayen~ a~d
the inc~eased urf ace area of the linar in~re~se the likelihood
that the liner will a~ect the flavor of the ba0r.
Oth~r crown llner~ h~ve b~en u3e~ or proposed, but all
have ~ r proble~, FoY example, polyethyl~ne And ~thylene
vinyl ace~ate liner~ have an even ~reate~ e~ect than PVC, by
-~cavengin~ vor co~pone~t~ from the beer. In U.S. Patent
3,799,380 to Ha~him~to et al, a bo~tle crown llner iB formed by
reaoting,l in th~ crown ~hell,~ a polyol and an Aromatic i~ocyanate
to ~or~ a ~hermo~et po~yureth~ne. This approach require~ new
equip~ent to replac~ th~ 6tandard PVC llne~ and re~u~res that the
bottle crown manufa~turer maintain the highe~ manufacturing
~tand~r~ to a~sure complete reactlon of the monomer~ ~nd
co~plste ~e~ov~l of Bolvent~ and ~taly~t~. Even wh~n t~e
proce~ carried out ~ith ~tmost care,l ~he proce~ senerally
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require~ the u~ oE an exce~3 of toxic i~ocyanate~v whi~h are
rea~ted after the main po~ymer1za~i~n ~eaotion hs~ been
coupleted. Moreover, a ~ub~a~tial curlng period i~ r~quired,
pref~r~bly at elevated te~p~rature. T~e r~s~lting t~moset
polyurethane l~ner m~y h~ve physloal and c~Qmlcal p~operti~
lJ~ ~;
wh~ch are not altogether ~eairable. An e~rl~er~patent to
Mahoney, ~o. 3,~42,411, diaclo~e~ a ~i~ilar approach, with a
foamed polyureth~ne.
Summa~y of the Inventio~
One of the ob~ects o~ this lnventlon 1~ to prov~d~ a
bottl~ crown which proviAes b~tter ~lavor prot~ction than crown~
known heretofor~, pa~ticula~ly when use~ on beer bot~les,
Anothe~ objeat i8 to provide ~uch a crown whose liner
lacks extract~bLe addltlves and doe~ not ~caven~e ~lavor
compone~ts ~rDm beer,
Another ob~ct 18 to provide ~uch a crown which m~y be
manu~ctured us1ng exiutin~ equipment;~ ~ncl~ding extrud~rs.
A~other ob~ect iB to provide ~uch ~ crown wh~ch i~
e~ler to a~emble and ha~ bro~der manuf~c~uring para~stex~,
including liner mold~ng temper~ture~.
A~oth~r ob~ect iu ~o provid~ ~uch a orown who e llner
ha~ ~ high degree of memory. and therefv~e maintai~ a ~eal ~ven
after it ha~ be~n compre~ed for long p~rlod~.
Another ob~ct i3 to provlde ~uch ~ crown who~e li~r is
highly adh~ive to the crown sh~ll.
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Other ob~e~t~ ~ill o~aur to tho~e ~kllled in th~ ar~ in
ligh~ of the following ~e~ription and a~com~anying dr~wlng~.
In ac~ordance with one a~pect vf thls invention,
ge~er~ ated, a con~iner clo~lure 1~ provided whlch lnclu~e~
a ~hell ~nd ~ liner, the liner being ~ormed of ther~opl~ti~
polyurethane eLa~to~er. ~he polyurethane~ which are u~e~ul ln
the pra~en~ ~nYantion mu~t be thermopla~ic ~a~her ~han
thermosetting, but thelr exaat chemlcal co~po~ition h~ not been
~ound to be critical ~o thelr u~efulne~e in the lnventi~n.
~ he clo3ure ~hell i8 made of a material which provid~
the required strength to hold the closure ~o the contalner, and
i8 pr~exably made of ~et~l. In ~h~ pr~erred e~odimen~, the
cl08ure iB a bo~tle crown ~p, most pre~erably ~or A beer bottle.
The ~he~mopla~tic polyurethane elastomer iB applled to
the bottle ~rown ~hell a~ a co~pletely reacted poly~er~
conta1ning neither pla~ticizer nor non-reacted mono~er~. The
ther~opla3tic polyuret?lane~ have a wide ran~e of hardness, and do
not change that hardne~s app~ci~bly ove~ a wids temperature
range. They have good low ~emperature ~l~xibility. high abra~ion
re~ ance, good ela~ticity~ snd good memory propert~e~ caus~
these ou~andlng qu~7ltie~ ~re bu11t into the b~ckbone of ~h~
pDlym~r, and are no~ produced by additiv~, they r~ain ~t~ble
when the liner ii expos~d to ~eer or oth~r conte~t~ o~ the
~ontainer. ~he ther~Qpl~tlc Rolyur~than~s ~re meltabl~ without
a~fecting thei~ chemio~l prope~ti~, and the mol~en polymer i~
ea~ily ~olded. I ha~e ~oun~ th~t the mater1a~ ~ function well in
all resp~ts a~ crown liners, ~itho~t r~uirln~ the addition of
plastlcizers, ~o:Etsning a~ent3 or ~ntioxidant~.
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Many of the propertia~ o~ thermopla~tic polyurethan~
ar~ well known ~nd are a~t o~t, ~or example, in the K~rX~O~h~sr
Encyclope~a o~ Chemlcal Ta~nology, Thtrd Editlon, parti~ularly
at volu~e 8, page~ 6~-40, e~pecially page~ 632-35, volu~e 10,
page~ 216-24~, e~pealally page ~32, and volume 23, page3 ~76-608,
The use o~ thermopla~tl~ polyurethane ela~tomer~ a~
liners for beer bottle crown cap~ f~lls a long-~elt n~ed ln the
beer lndu~try. Pro~bly bec~uue o the p~rceived danger in u~lng
a material baq~d o~ l~ocyannte~ ar~d because Of the di~f iculties
atten~an~ upon th~ previou~ly proposed thermvset polyurethaneq,
~he ~e of ther~oplastic polyurethanas ~8 clo~ur~ liners h~s not
been heretofore prop~sed. Nonetheless, the thermopla~tic
polyuretha~e ela~to~erq axe fully rea~ted and cur~d before ~eing
formed l~to pellet~ of flakes7 and are thereoYe inert. Any
slight t~a~e of free isocy~n~te which mlght happen to be in ~he
~a~erl~ls i~ driven off w~en the ~ateri~lQ are he~ted and
extrud~d. The ~hor~opl~ti~ poly~rethanes h~v~ been found to
produce no ~h~ng~ in the fl~vor of beer ~tore~ ln bot~les closed
with the bo~tle ~rown of the invention, elther by ext~actton of
~aterial3 ~rom the polymer~ or by absorp~ion of flavorant~ ~rom
the b~er. Be~u~e the ther~opla3ti~ polyureth~ne ~evelop~ a
memory when it i~ melted and cooled, it tend~ to ret~i~ lt~ shape
and return~ to 1~, even ~fter ~elng compre~ed. It ther~fo~e has
~upertor ~e~ling capab~ltty. ~he thermopla~tic polyurethAne is
known for it~ adh~sive qu~l~ti~, and adhere~ ten~iously to the
metal crown ~hell, ~ut the coolsd poly~r ~oe~ n~t stlck to the
glas~ bottle.
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Pre~rably, ~he polyurethane line~ h~ a h~rdne~ o~ the
order of Shore 60A ~o 7SD, mo~t prefer~bly in the range of 6~A to
lOOA. The polyureth~ne ~hould nb~ be t~cky ~t nor~al
~emperatures (under 100 ~,). For convenience in Porming th~
liner, it should have a m~lting po1nt below abvut 450~F ~3$~C),
sOth polye~her a"d polye~ter polyurethane~ are uaeful~ an4 blendu
of the~e ~ypa~ ~re par~icularly de~rable to impart the high
degres of ~ydrolytlc ~tabllity of the polyether polyurethane ~nd
tho ga~ imper~eAbility o~ ~he polye~ter polyurethane.
EitheY ~romatic or aliphatl~ polyur~thane~ ~8y be
utili2ed a~ the llner.
~ n the method o~ th~ invention, a completaly reacted
th~rmopla~tic polyureth~ne 19 ~elted and appllea to the ln~ld~ o~
a bot~le crown ~hell to form a liner~ Ths polyurethan~ i~
cooled. T~ cap i~ then ~ppll~d to a ~ontal~e~. The container
iB prefer~bly a beer bottle, but the inv~ntion ~ay ~l~o be ~ed
with other container~ ~illed with other ~aterl~ or ~x~mple
other bevera~a~ ~u~h aB carbona~od 80~t drinX~ or wine.
Pr~f~rably~ the thermopl~ polyurethane liner 1
applied as ~ ~llm, and iB no~ ~oa~d or blown in any way.
Other aspects of the inventlon will be better ~nd~r~tood
in v~ew of the ollowing de~cription o~ the preferred e~bodiment
and th~ appended ~laim~
Brief D~s~lp~Lon o~ th~ D~awin~
~ n t~e dr~wings, F~¢UR~ 1 i8 ~ View in C~O~B s~ction of
a bottle crown cap having a the moplastic p~lyuret~ne llner in
ao~ord~nce with the present inventio~.
FIG~E 2 i~ a pl~n view of the crown cap of ~IGURE lo
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FIGURE 3 is a view in cross section of the crown cap
of ~IGURES 1 and 2 applied to a bottle,
Description of the Preferred Embodiment
Referring to the drawings, reference numeral 1
indicates a bottle crown cap in accordance with the present
invention. The crown 1 includes a shell 3, made of steel,
and a liner 5 made of a thermoplastic polyurethane
elastomer. An example of a suitable polyurethane is a
commercially available material sold under the trademark
~-THANE PN-03 by K.J. Quinn & Co,., Inc. o~ Malden,
Massachusetts, This material is a thermoplastic aliphatic
polyurethane and is described in a brochure published by K.J.
Quinn & Co. entitled "Introduction and General Information to
Q-THANE Thermoplastic Polyurethane Resins."
Other preferred thermoplastic polyurethane resins
include a variety of extrusion grade thermoplastic
polyurethane elastomers. Q-THANE resins, such as Q-THANE
P-455, all sold by K.J. Quinn ~ Co., may be used. Extrusion
grade resins sold under the name Pellethane* by the Upjohn
~0 Company are described in Upjohn's "Pellethane* Processing
Guide" and in "DSG Reports" 16, 17 and 20. Examples of these
resins are Pellethane* 2102-80AE and Pellethane* 2103-80PF.
Extrusion grade resins sold under the name LIBE~AN* by Nippon
Elastollan Industries Ltd., Tokyo, Japan may also he used.
These polymers are described in a brochure entitled
"Thermoplastic Polyurethane LIBERAN." Examples of suitable
materials are LIBERAN E-380 and E-390. These products, as a
group, cover a wide range of chemical compositions and a
range of hardnesses from Shore 60A to 75D. The extrusion grade
* Trade Marks
materials have a hardness of from Shore 60 A to 100A. Aromatic
and aliphatic polyurethanes, of both the polyester and polyether
types, are included.
EXAMPLE 1
A steel bottle crown shell 3 is cleaned and degreased i n
accordance with good manufacturing practice. The shell B is
placed at the outlet of an extruder to which is added Q-THANE
PN-03 in flake form. The flake material is dried in accordance
with good manufacturing practice. The extruder has a barrel
temperature of 390°-410°F (200°-210°C), sufficient to melt the
thermoplastic polyurethane polymer. The melted polymer is
applied as a ring to the inside of the shell to a thickness of
about 10 mils, to form a a liner 5. The polymer is allowed to cool
to room temperature. The cap 1 is then placed on a filler beer
bottle. Maximum strength is obtained if the cap is maintained at
about 110°C for ten hours prior to cooling. This period of
elevated heat is not, however, essential to proper functioning of
the cap 1.
EXAMPLE 2
A thin sheet of Q-THANE PN-03 thermoplastic polyurethane
is extruded as in the preceding example. A 3/4 inch square of
the materials placed in a beer bottle, and the bottle is filled
on conventional filling equipment, crowned, and pasteurized. The
bottles were stored for two weeks at 85°F., then cooled and
opened. A panel of tasters could detect no flavor change. The
square of material was analyzed and found to have extracted no
significant flavorants from the beer. By way of comparison, the
best previously known crown liner material also produced no
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aeteotable ~lavor c~ange and e~racted no significant flavorant~
from the beec. ~he amoun~ o~ ~1AVOrant~ ex~acted ~y the
thermopla~ic polyurethane, however, was half th~t ~x~rac~ed by
the prior art m~te~
The bottle o~ ~x~mple 1 showed excellen~ oh~ac~eri~tic~
in standard ~tack test ~nd leak te~ts.
~ umerous vari~tion~ in the co~tainer ~10BULe and method
of the pre~ent invention, within the ~cope o~ the appended
cLaim~, will OCCUL to tho~e skil~ed in the art in light o~ the
~oregoing di~¢los~re. ~erely by way of ex~ple, tne ~hell 3 ~y
be made of other me~als or of other mate~ial~ s~oh as ridgid
pla~tio~ which have the req~i~ed strength ohaxao~ri~tics. The
thermoplastic polyurethane ~ay be applied by di~er~nt me~-hod~.
The e v~riations a~e merely illustrative.
