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Патент USA US2406227

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Aug..20, 1946.7
E. G. KING
"
CONTAINER CLOSURE
. Fil'edJ'une so, 1944
' 2,406,227
Patented Aug. 20, 1946
2,406,227
UNITED STATES PATENT OFFICE
2,406,227
CONTAINER CLOSURE
I
Ellis Gray King, ‘Pittsburgh, Pa., assignor to
Armstrong Cork Company, Lancaster, Pa., a
corporation of Pennsylvania
Application J-une'30, 1944, Serial'INO.~_542,895
14 Claims.
(Cl. -215—40)
2
cerned with a, container closure including a vseal
ing element formed ‘of a ‘tough ‘flexible’, vcured
alkyd resin consisting of ‘the reaction product
of a saturated aliphatic dibasic acid, 'dipropylen'e
become rancid.
more fully hereinafter set forth.
'
,
Closures are used with a large ‘variety of ‘con
'
'
It is "an object of this invention to provide an
improved closure comprising a shell and a novel
glycol and an unsaturated ‘aliphatic di'basic acid.
The particular "acids and ‘proportions thereof
which ‘maybe used to achieve my :new results are
.
i?ed with adrying oil do cure to ar-tackefreeicon
dition, the wdryingoil tends to impart taste ‘and
‘odor to the contents of thecontainer, especially
if there is a small amount of oil jpresen-tthat ‘has
This invention relates to ‘:containerclosures in
cluding sealing elements and is ‘primarily con
and improved closure sealing "element.
'
.It is a further 'object'of this invention to pro
10 vide a closure comprising avshell and an improved
sealing element :formed 'of a particular alkyd
tainers, such as bottles, jars, cans, pails, and the
like. A sealing element or liner is requirediin
‘substantially all. vtypes of container ‘closures.
resin.
‘
‘
I have discovered an improved container clo
sure comprising ‘a shell of any desired con?gura
tion and a sealing element of a certain cured
These liners must he relatively'tou'gh, flexible,
alkyd resin which‘functions‘particularly satisfac
tory as a closure sealing’ element, The condensed
alkyd resin has the important and highly de
and resilient so ‘that a tight seal is formed be
tween the closure sealing element‘ and they ‘lip
of the container and mustlbe‘i-sui?ciently devoid
of cold flow so that thesealji'sl,maintained 'Iin
sirable advantage in that “it can be readily poured '
into a closure and relatively easily cured therein
‘de?nitely. The liner should bev ‘impervious to gas
even at elevated ‘temperatures and pressures and
must not impart an objectionable taste or odor
‘to ‘form a fsealing‘element. "The fact that the
to the ‘food or beverage within 'thecontainer.
resin ‘canbe poured ‘into the ~=c1osureshel1 and
‘cured "is highly desirable in that 'preforming and
Further, the sealing element should be non-tacky
inserting problems are eliminated.
so that portions thereof “will ‘not adhere ‘to the 25
This ‘and other advantages and objects willrb'e
come more apparent ‘when the following descrip
tion is considered along with the accompanying
container lip and be unsightly when the closure
is ‘removed and must be vrelatively insoluble and
drawing, in Which:_
infusible so as to be substantially unaffected by
a large variety of container contents.
'
Certain compositions have been proposed or
'
30
used heretofore as materials suitable for use in .
container closures as sealing liners. For example,
rubberand rubber compositions have been ‘used,
but rubber, and especially vulcanized‘ rubber,
'ten'd's'to impart an ‘objectionable odor and taste
‘to the container‘ contents. 'Alkyd resins ‘which
are the reaction product of a polyhydric alcohol
and ‘a polyba'sic acidhave, in general, been'found
‘to have serious drawbacks which make them un
desirable as sealing elements in closures.
example, alkyd resins of. the saturated dibasic
acid~po1yhydricalcoho1 type vcure by condensa
t‘ion, yielding water which tends to produce a
porous structure'which will not form a gas-tight
seal. Further, these resins ‘require extended pe
'r-iod's at high temperatures to effect curing, and
what is most ‘important, these resins are too
viscous to ‘be pouredreadilyiinto a closure for
forming therein a sealing element. ‘Reducing the
‘reaction time so as to produce'less viscous resins
idoesinot T‘solvethe problem for ‘such less viscous
resins require even a longer time 'Ifor'curi'ng {and
produce'even more water during condensation.
‘Many of the other alkyd resins-cannot be readily
cured. While many of those alkydjaresins' mode 55
Figure 1 is a sectional view of a crown type
closure embodying my invention;
Figure 2 is a plan view of the closure of Figure
1;and,
.
J
Figure 3 is a sectional ‘View of another type of
closure also embodying my invention.
Referring more particularly to Figures 1 and 2,
‘a ‘crown closure '5 comprises a shell 6 and 'a seal
ing element '1. The sealing element 1 is shown
in the form‘ of a disk but may be in the form
of an 'annularring ‘as shown in Figure 3. When
the closure 5 is placed on a container, such as a
‘bottle, the sealing'element 1 engages ‘a ‘up on'ith'e
bottle to form a gas-tight seal.
Figure 3 shows a different type of closure 8
comprising a shell 9 having an annular groove
Ill-formed therein. The groove 10 contains an
annular sealing ring ll.
. v
’
My new closures are not limited ._to any par
ticular-‘shape or design of either the closure shell
ornthe sealing wmember though. .I am primarily
concerned with the .well-knowncroWn-type clo
sureyfsuch
is show-min Figured.
The sealing elements 1 Tand ‘I I; are formed-from
an alkyd resin which must be preparedgby con
densing and curing-aymiXtu-re- comprising a :sat
2,406,227
'
‘
3
'
.
-'
,.i
,.
4
V .
dibasic acid is employed, the alkyd resin may not’
cure, or if it does, it is relatively soft and tends
and an unsaturated aliphatic dibasic acid. 7
to crack under pressure and may be tacky. If
The saturated aliphatic dibasic acid which may
a relatively smaller amount of saturated dibasic
be used is any one of a limited group of such
acids containing 4 to 10 carbon atoms. For ex C71 acid is used, the resin is too hard and does not
compress sufficiently to form a satisfactory seal
ample, succinic acid, adipic acid, or sebacic acid
ing element. I especially prefer to employ from
may be used, though I prefer to use adipic acid.
0.25 mol to 1.0 .mol of adipic acid for each mol
While polybasic acids other than those just de
of maleic acid, fumaric acid, or maleic anhydride
?ned can be used in manufacturing alkyd resins‘,
such other acids are not satisfactory with dipro; 10 for it has been found that this resin is especially 7 .
useful for crown type closures where the sealing
pylene glycol for my purposes.
.
urated aliphatic dibasic acid, dipropylene glycol,
- element must retain relatively high carbonation
The unsaturated dibasic acid may be any, un
saturated aliphatic dibasic acid , containing 4
_ pressures.
With‘ the above-mentioned proportions ofacids, 1
to 5 carbon atoms in which the carbonyl groups
are attached to’two different carbon atoms and 15 it is only intended _'to include dipropylene glycol
as the polyhydric alcohol. While I prefer to em
in which the carbon to carbon double bond is con-1
ploy fthe dipropyleneiglycol in a molal amount
jugated with at least one of the carbonyl groups,
equal to the total molal amount of both acids,
For example, maleic acid or anhydridafumaric
acid, itaconic acid, citraconic acid, and the like‘, 7 there may be present excess amounts of either the
or mixtures thereof, may be used, though We pre-' 20 acids‘in the above-mentioned ratios or there may
fer maleic acid, maleic anhydridefand fumaric
be present anexcess amount of the glycol so long
. acid; 'Malic' acid "which yields‘ fumaric acid,
as the excess acids or glycol are not present in an
amount sui?cient to prevent the formation by
condensation of a soluble, fusible resin having an
to the reaction temperature can be used for it is
the products, fumaric acid and maleic anhydride, 25 average molecularw'eight of at least 1,000. When
there are present inthe reaction mixture’ ex
which react. Fumaric acid at the temperatures
actly equalrmolal amounts of glycol and- acid,
‘of the reaction forms maleic anhydride and is,
each condensation polymer theoretically has one
therefore, a' full equivalent of maleic acid. It is
terminal hydroxyl group and one terminal car
well recognized that‘anhydrides of such dibasic
‘maleic anhydride, and wateriuponibeingheated
30 boxyl group, whereas, if there is an excess amount '
acids are the full equivalentsof the acids. .
of either acid or glycol, the polymers cannot con- ,
To further illustrate the de?nition of the un
saturated aliphatic dibasic acid, maleic acid
has the‘formula,
,
'
dense without loss of the constituent in excess
beyond that point where all terminal groups are
the same; that is, where all terminal groups are
35 either hydroxyl groups or carboxyl groups.
The cured, relatively infusible and insoluble
alkydv resin is produced as the result of two dif
ferent types of chemical reactions; The ?rst
reaction comprises an esteri?cation or condensa
=These carbonyl groupsare connected to two dif
'40 tion reaction in which the acids and the alcohol
combine with the elimination of Water to form a
fluid polyester resin of relatively low viscosity. In
ferent carbon atoms. While in.‘ maleic acid the
carbon to carbon double bond is conjugated with
each of the carbonyl double bonds, it is only'nec
essary for the carbon to carbon double bond to be
conjugated'with one‘ of the, carbonyl groups, as in
~itaconic where the formula is written as
theisecond reaction,’ there is effected across
' linking of the polyesters formed by condensation
through the double bonds of the unsaturated acid
present in such polymers to produce arrelatively
'infusible and insoluble cured alkyd resin con
sisting' of relatively large complex polymers.
I
prefer to cure the alkyd resin in an inert atmos
50 phere, such as carbondioxide, nitrogen, or the
likepwith the aid of a catalyst, such as ben
zoyl peroxide, though the resin may be cured to
a tack-free condition in any‘ other satisfactory
manner.
.
|
' l
l
I
1
I The benzoyl peroxide is a solid and may be
V
is present, the unsaturated aliphatic acid comes
within the term “conjugated.”
added to the resin in any known manner,“ though
I prefer to dissolve it in styrene and then add ,.
this solution to the condensed resin to aid in
curing the resin. The use of styrene is advanta
urated 'dibasic'acid and either maleic acid, fu 60 geous inthat it increases the ?uidity of the resin
without causing bubbles in the resin during our;
maric acid, or maleic, anhydride as the unsat
While any of the aforementioned acids may be
used, I prefer'to employ adipic acid as the sat
urated
dibasic
acid.
I
_
I
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r
ing.v -I have used up to 30 parts of styrene to 100
a
The ratio of saturatedY-dibasic acid to unsat
urated dibasic acid is critical. I have discovered '
that any of the saturated dibasic acids falling
within the scope of my de?nition, may be used in
an amount ranging from‘ 36.5 grams to 219 grams
for each gram vmolecular weight of unsaturated
I aliphatic acid; Thus, with each mol of iunsatu
rated-acid,>there can be reacted from 0.25 mol‘to
1.5 mols of adipic acid, though when adipic acid is
the saturated acid, Iliprefer to use from 0.25 mol
to 71.0 mol of adipic acid for each mol'of unsat
urated dibasic'acid.
'
'
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-
‘I
If a relatively greater am‘ountof the saturated
parts of resin, though only about 10 partsby
weight of_ the styrene. polymerized, the remain;
,der being evaporated duringcuring. This quan- .7
tity of styrene tends to increase the toughness
of the resin and, therefore, a slightly smaller
amount of unsaturatedacidmay be used.
Alternatively, the benzoyl peroxide may be dis
solved in'benzene and added to the condensed
resin and the benzene, then eyaporatedor the '
‘benzoyl peroxide may» be added in :solidform
along with a curer, suche'as calcium sulphate.
Other organic peroxide polymerization catalysts
‘may be used,
.
2,406,227
5
Example 3
,
‘ I ‘prefer to form the sealing element within the
closure by pouring the relatively ?uid ‘resin re
Closures were ‘prepared as follows:
sulting from the ?rst condensation reaction ‘into
' Grams’
the closure seal and then curing the alkyd "resin.
Itaconic acid-_____...-,_.______.___.______....__- 104 _
If desirable, the alkyd resin ingredients may be
Adipic acid
__
’
117
esteri?ed, cured by molding in the formoi sheets
Dipropylene glycol ________________ __»_.__..- 2114
and then annular rings or disks may ‘be die cut
Hydroqulnone (anti-oxidant) __________ ..'__ '
therefrom and such a preformed sealing- element
These ingredients were thoroughly mixed and
inserted into the'closure.
The following detailed examples, in which all 10 then condensed :asdescribed in‘ Example 1. 'The
curable resin ‘had an :acid number of 35.2.
parts are by weight, further illustrate my inven
'Thisresln was compounded as follows:
tion,.-though my invention is not limited ‘to exact
proportions or materials except as set forth in
Grams
the accompanying claims.
Resin ______'____-__,____._-____._-_..___.._--_ .95
0;‘5
15 Benzoyl peroxide
Example. 1
Styrene
Closures having good sealing characteristics »
were prepared as .follows:
Grams
Maleic anhydride____._._______-..__-_____.. 78.4 20
Adipic
acid
Dipropylene
,
‘
_
.41‘:
Iron oxide _________ __.,_______________ __._ '47,..5
v58.5
glycol _____ __, _____________ .._. ‘1164.8
Satisfactory closures. were formedandztested
as described in Example 1.
-
"
'
All of the closures described in .the ‘foregoing
examples were found to be highly satisfactory
for retaining .relatively'high carbonation pres
sures such asare encountered during the Ebottling
These ingredients were mixed ‘and then heated
gradually with stirring to 200° C. while carbon
dioxide was passed through the heated container.
and pasteurization'rof carbonated beverages‘.
The speci?c alkyd resins which I haveround to
A trap was installed and 25 cc. of xylene was
be useful in‘ forming: sealing elements of - ~closures
added and the temperature held at about 200° C.
for 4% ‘hours. Thereafter, vacuum was ‘applied
may or may not be compounded witht?llers.‘ It
is preferred to employ ‘?llers, as ‘they rten'drto
for 30 minutes at 110°‘ C. to remove excess ‘xylene. 30 reduce the cost. Any ‘of the customary ?llers
may .beemployed; for example, iron oxide, slate,
The curable-condensation reaction'product had
calcium carbonate, potter’s hint, and the .likeRor
an acid number of 35.9.
This curable ‘resin was compounded as follows:
Grams
Resin
_______ -__ _____ .__, _________ _... ____ __
Benzoyl peroxide _______________________ .__
mixtures
35
95
‘0.5
~
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'
a
‘
7
obvious "that some features: may. be employed
without others, all :without departing Yfromwthe
spirit orscope ‘of my invention de?ned in " the
Styrene _..___..__._______.__..___;__..__...__..-_- 4.5
accompanying claims.
Finely divided red slate _________________ __ 166.7
These ingredients were thoroughly mixed and
the resinous composition ‘poured into crown
shells. The resin was then cured under carbon
thereof.
Having described my invention in detail, ‘it'ni's
I claim:
‘
1. .A closure comprising
40'element
includinga cured
a shell and a sealing
alkyd resin consisting
of the cured condensation reaction product of
from ‘36.5 .to 219 grams of :ausaturated ‘aliphatic
dibasic acid containing .4 to 10 carbon atoms; one
gram molecular weight of ‘an unsaturated ali
dioxide gas for 35 minutes at 130° C‘.IThe closures
were tested on containers containing 4.5 volumes
of dissolved CO2 gas and retained carbonation 4‘ ‘ phaticdibasic acid containing from 4‘to 5 carbon
atoms and in which the two carbonyl groups are
A second ‘batch of this resinous .compositio
connected
to two different carbonatoms and in
was cured in a closed mold for ‘30minutes1at ‘130°
which the carbon to carbon double bond is con
C. to form a ?exiblaresilient product. ‘Sealing
elements were cut from this cured composition 60 jugated with at .least one of the carbonyldouble
bonds; and . dipropylene glycol in an amount
and were found to perform satisfactorily,
su?icient to condense with said acids and form ‘a
Example 2
resinous condensation product having an average
for one week at 125° F.
molecular weight ofrat least 1,000.
Closures were prepared as :follows:
55
2. A closure comprising. a shell land a seal-in
element including a cured alkyd resin: consist~
Maleic anhydride ______________________ __ ~98
ing of the curedcondensation reaction ‘product
Sebacic acid______.__-.__________.._._______ 36.5
of from 0.25 to ‘1.5 mols of adipic acid; one gram
Dipropylene glycol ___________________ -_ 159
molecular weight. of an unsaturated aliphatic di
These ingredients were mixed and 'a curable 60 basic ‘acid containing from :4to‘5 carbon-atoms
and in which the two carbonyl groups: ‘are con
resin prepared as described in Example 1, except
nected to twodi?erent carbon atoms and in which
that (the ‘mixture was heated at about 200° C‘. ‘for
the carbon torcarbon double bond is conjugated
4 hours. The resin had an acid number of 34.3.
with at least one of the carbonyl double bonds;
This resin was compounded as follows:
and dipropylene glycol in an amount 'fsu?icient
Grams
to condense with said acids and form a; resinous
Resin
________________________________ __ 95
condensation product having an average molecu
Benzoyl peroxide ___________________ __.____ 0.5
lar weight of at least 1,000.
Styrene _______________________.________r_ 4.5
-
.
~Grams
3. A closure comprising a shell and a sealing
70 element including a cured alkyd resin consisting
Closures were prepared and tested as described
of the cured condensation reaction product of
under Example 1. The sealing elements per
from 36.5 to 219 grams of a saturated aliphatic
formed satisfactorily, though this cured resin was
dibasic acid containing 4 to 10 carbon atoms; one
somewhat harder than that described in Exam
gram molecular weight of an unsaturated ali
ple 1.
75 phatic dibasic acid containing from 4 to 5 carbon
Iron oxide ________________ __"_ __________ __ 66.7
2,406,227
anhydride; and dipropylene glycol in a mole!
atoms and in which the two-carbonyl groups are
amount substantially'equal to the total molal
connected to two idi?erent carbon atoms and, in
amount of both said adipic acid and ‘said un-'
which the carbon to carbon‘ double bond is con
‘J'ug'ate'd with at least one of the carbonyl double
bonds; and dipropylene glycol in a molal‘amoun‘t
substantially equal to the total molal amount of
both of said saturated and said unsaturated acids.
saturated
acid.
,
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I
V
9. A closure comprising a shell and a sealing
element including a cured alkyd resin consisting
of the cured condensation reaction product of
ofthecured condensation reaction product of
from 36.5 to 219 grams of a saturated aliphatic
dibasic acid containing 4 to 10 carbon atoms;
onegram molecular weight of - maleic acid; and
froml0.25 to 1.5;mols of adipic acid; one gram
molecular weight of an unsaturated aliphatic di
condense with said acids and form a resinous
'4. A closure comprising a shell and a sealing
‘elementincluding a cured alkyd resin consisting
dipropylene glycol in__an amount suf?rcient to
condensation product having an average molecu'—
basicacid containing from 4 to 5 carbon atoms
and in which the two carbonyl groups are con
lar weight of at least 1,000. ;
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1 . I
‘
'7
10. A closure comprising a shell and ‘a sealing
nected to two‘ different carbon atomsand in which 15
element including a' cured alkyd resin consisting
the carbon to carbon double bond is conjugated
with'at least'one of ‘the carbonyl double bonds’;
of the cured condensationfreaction product of
and dipropylene glycol‘in a molal amount sub
from 36.5 to 219'grams of a saturated ‘aliphatic
dibasic acid containing 4 to 10 carbon atoms;
one gram molecular weight of maleic acid; and
dipropylene glycol in a molal amount substan-V
tially ‘equal to the total molal amount of both
'stantially equal‘ .to the‘ molalamount of both
said adipic acid and said unsaturated acid.
' "5; Aclosure comprising a shell'and‘a‘ sealing
1270
element‘includinga cured alkyd resin consisting
of the; cured ‘condensation, reaction‘ product of ' said saturated acid and said maleic acid.
11. A closure comprising a shell and a sealing
‘from 0.25 to 1.0;mol of adipic acid; one ‘mol of
'an unsaturated aliphatic'dibasic acid containing 25 element including acured alkyd resin consisting
of the cured condensation reaction product of
from 4 to 5 carbon atoms and in which the two
carbonyl groups are connected to two different
carbon atoms andvin which the ‘carbon to carbon
double bond is conjugated ‘with at least one of
from 0.25 to 1.0 mol of adipicacid; one mol of
maleic acid; and dipropylene glycol in an amount ,
sufficient to condense with said acids and form
the ‘carbonyl. double bonds; and dipropylene gly 30 a resinous condensation, product having an av
erage molecular weight of atleast 1,000.
127. A closure comprising a shell and a sealing
element including a cured alkyd resin consisting
of the .cured condensation reaction product of
. '6,.-'A_.closure‘comprising a'shell and ‘a sealing 35 fro'ni025 to 1.0 mol of'adipic acid; one mol of
element-including a cured'alkyd resin consisting
maleic acid; and dipropylene ‘glycol in a molal
amount substantially equal to the total molal
of'the cured‘condensati'on reaction "product'of
col in an'amount suf?cient to condense with said
acids vand‘form a resinous condensation product
‘ having an averagepmolecular weight of at'least
11,000;
1
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_
V
V
a
V
e
‘from 0.25 to 1 mol of adipic acid; one mol of a
compound selected from the group consisting of
amountpof both said adipic acid and said maleic
acid.
-
-
a
-
maleic‘ acid, fumaric acid; and maleic anhydride;
13. A closure comprising a shell and a sealing
and dipropylene glycol 'in an amount sufficient to
element including ?ller'a'nd a binder comprising
condense with said acids and form a resinous
a cured alkyd resin consisting of the cured con
condensation product having an average molec
densation reactionrproduct of 0.5 mol of adipic
acid; one mol of maleic anhydride; and;1.5 mols
ular weight of at least
1,000. *
.
>
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'7. A closure comprising a shell and a sealing
element including a cured alkyd resin consist
ing of the cured condensation reaction product
of from 0.25 to 1.0 mol of adipic acid; one mol
l of an unsaturated’ aliphatic dibasic acid con;
taining from 4 to. 5 carbon atoms and in which ‘
the two carbonyl groups are connected to two dif-'
,ferent carbon atoms and in'which the carbon
to carbon double bond is conjugated with 'at
least one of the‘ carbonyl double bonds;.and di-'
propylene glycol in a molal amount substantially
equal to the total molal amount of both said
adipic acid and said unsaturated acid. '
7
'
8. A closure comprising a shell and a sealing
i of dipropylene glycol.
‘14. A' closure comprising a shell and a sealing
element including a binder consisting of at least
90%.by weight of a cured alkyd resin and not
more than 10% by Weight of polystyrene, said
cured alkyd resin consisting of the cured con
densation reaction product of from 36.5 to 219
grams of a saturated aliphatic dibasic acid con
taining 4 to 10 carbon atoms; one gram molecular
weight of an unsaturated aliphatic dibasic acid
containing from 4 to 5 carbon atoms and in which
the twocarbonyl groups are connected with two
different carbon atoms and in which the carbon
to carbon double bond is conjugated with at least
one of- the carbonyl double bonds; ‘and dipropyl
element including a cured alkyd resin consisting
of the cured condensation reaction product of 60 ene glycol in a molal amounttsubstantially equal
from 0.25 1501.0 mol of adipic acidy'one mol of
to the total molal amount of both said saturated V
Ldibasic acid and said unsaturated dibasic acid.
an unsaturated acid selected from the group con
sisting of ‘maleic acid, fumaric acid, and maleic
’
‘
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