Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates to sealing compositions suitable for sealing con-
tainer closures such as top or bottom end closures of cans or replaceable or non-
r0placeable caps for jars or bottles. The compositions can be used for other
sealing purposes but, for clarity, since they are formulated to meet the particu-
lar requirements of can and other container closure seals the invention is des-
cribed solely in terms of compositions for sealing container closures.
Traditional sealing compositions have comprised a liquid medium in which
has been dispersed or dissolved solid polymeric material into which has previously
been milled fillers and other additives. The solid polymer into which the addi-
tives were milled may previously have been formed by coagulation of, for instance,
rubber latex.
In recent years there has been increased interest in sealing composi-
tions based on a latex of a rubbery polymer and into which has been dispersed fil-
ler and other additives. Thus in this composition the polymer is obtained initi-` ally as a latex, for instance by emulsion polymerisation, and is used directly in
this form, without first being coagulated or otherwise solidified. These latex-
based compositions are particularly convenient to manufacture, since the additives
can be incorporated in them merely by stirring them into the latex, but they do
require the use of carefully selected materials in order to obtain optimum proper-
ties. Such compositions have been widely sold commercially. Also typical com-
positions of this type are described in British Patent Specification No. 1,566,
92~.
The liquid composition is applied to one at least of the mating surfac-
es of the closure and the sealing face of the container, generally to the clos--ure, and is then dried on the surface. The closwre is pressed onto the sealing
face of the container so as to grip the container firmly and the composition pro-
vides a seal between the container and the closure. It is necessary that the
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composition should have appropriate rheological and other physical properties.
For instance when applied to can ends it should flow adequately during sealing so
as to distribute itself over the mating surfaces, but preferably it does not flow
to such an extent that significant extrusion of the composition occurs along the
` walls of the can.
The seal provided by the composition should prevent ingress of bacteria.
Generally it should also prevent loss of liquid, vacuum or gas.
It is difficult to formulate latex compositions that will reliably meet
these requirements using readily available and economically attractive materials.
~pical compositions comprise polymer latex~ filler, tackifying resin and various
other additives that are present to improve the stability of the latex or to im-
prove the seal or both.
Typical fillers that are used include kaolin, talc, zinc oxide and cal-
cium carbonate. Generally the amount of filler must not be too high or else the
sealing properties are impaired.
; A wide variety of other fillers have been proposed in the literature.
~,
Such fillers are listed in, for instance, British Patent Specification No. 1,566,
. 924. Glass powder is mentioned in the long list of fillers in that specifica-
tion. However glass powder is obtained by crushing glass and so would inevitably
2~ cause very heavy wear of the nozzles by which the liquid composition is deposited
onto the closure and so has not been adopted commercially.
In United States Patent Specification No. 3,~09~567 a rather different
type of can sealing composition is described, namely a composition obtained by
dispersing into water milled solid rubber, filler and various other additives.
It is mentioned that micro-balloons can be included for the purpose of making a
porous layer.
It has been our object to modify the content of latex-based compositions
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for sealing container closures in such a way that either the seal is improved orthe amounts oE either the rubber or other e:Lastomeric material or the tackifying
resin, or both~ can be reduced without reducing the sealing properties. It has
also been our object to provide n~ethods of sealing containers using such composi-
tions, and to provide sealed containers.
A sealing composition according to the invention and that is suitable
for sealing container ends comprises a latex of a rubbery polynner and into which
has been dispersed filler including crush resistant glass beads having a particle
si~e of 1 to 200 microns.
Such a composition can be used for sealing the sealing face of a con-
tainer closure to the sealing face of a container in conventional manner~ Thus
the sealing face of the closure is lined with the composition, the composition is
dried to form a gasket, and the sealing face of the closure is compressed around
the end of the container thereby sealing the closure to the seal:ing ~ace with the
gasket within the seal. The product is a container having a closure sealed to it
by a seal that includes a gasket within the seal formed of the dried composition.
This sealed container may be fully sealed, for instance being a jar or
a one piece can or a can sealed at both ends, or it may be a can that has a clos-
ure sealed to it at one end but which is open at the other.
When the container is a bottle this gasket is trapped between the seal-
ing face of the rim of the bottle and the overlying closure. Preferably however
the container is a can in which event the gasket is trapped in the double seam
formed in conventional manner by compressing the outer per:Lphery of the container
closure around an outwardly extendLng flange oE the side wa:Ll and then press:lng
the Elange and the closure periphery against the side wall of the container, gen-
erally in a single operation.
; We have found that the inclusion of glass beads cloes, as a generality,
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resul~ in improved sealing properties compared to the same composition in which
an equivalent volume of other filler (such as kaolin) is used in place of the
glass beads. A number of sealing tests are used in the industry and are recog-
nised as being meaningful and by saying that the sealing properties are improved
we mean that the number of cans that fail a meaningful sealing test will be
reduced.
The beads must be crush resistant, that is to say they must have suffi-
cient strength to resist any risk of crushing during the sealing use to which the
composition is to be subjected. Thus in a can end sealing composition the beads
must have sufficient strength that they will not crush in the can end seal. The
beads can be hollow, provided the walls are sufficiently strong to resist crush-
ing but generally are solid. The beads may be ovoid in shape but preferably are
substantially spherical. The particle size of the beads is generally between 1
and 100 microns, most preferably 10 to 75 microns. The average particle size is
generally from 5 to 100 microns, most preferably 10 to 50 microns, with best res-
ults generally being achieved with an average size of 20 to 50 microns.
The glass beads are preferably formed of soda glass, most preferably of
"A" type glass. The beads have preferably been made by solidification of molten
glass droplets and may have been treated by a fire polishing process, in conven-
tional manner. Their surface may be untreated or they may ha~e been given a sur-
face coating of a variety of materials provided the surface coating does not
interact with other components in the composition in such a way as to reduce sig-
nificantly the sealing properties of the composition. For instance although many
silane surface coatings can be tolerated in many compositions, it may 'be undesir-
able to incorporate a mercapto silane if the polymer of the composition is capa-
ble of being vulcanised 'by sulphur, as the mercapto silane may then react so
strongly with the polymer as to interfere with the desired sealing properties.
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Throughout this specification amounts of components of the composition,
including amounts of glass beads and other fillers, are expressed as amounts by
. volume based on the volume of rubbery polymer, unless othcrwise specified. For
.i example 10% glass beads means that there are 10 volumes glass beads per 100 vol-
umes of solid rubbery polymer.
. The amount of glass beads in the composi~ion should be at least 1%,
since lower amounts tend to give inadequate improvement. Generally the amount isbelow 100%, and normally below 50%, since greater amounts tend not to give signi-
ficant further improvement. Generally the amount is at least 3% and preferably
at least 5%. Generally the amount is up to 30%. Typically the amount may be
: from 5 to 50%, most preferably 5 to 30%.
The filler may consist substantially only of glass beads, with the
result that the composition may contain no significant amounts of other fillers
although it may include fillers that are present primarily for their pigmentary
purposes, for instance titanium dioxide which may be present in amounts of up to10%.
Good results are also obtained when the filler does include particulate
inorganic material other than glass beads~ and this is generally preferred. The
: material other than glass may be present in an amount of 0 to 150% (based on the
volume of rubbery polymer, generally 10 to 120% and preferably 50 to 100%~. Pre-ferably the composition includes 0.05 to 2 parts, most preferably 0.1 to 1 part,by volume glass beads per part by volume other inorganic particulate filler.
- Although the total volume of filler, including glass beads, can be sim-
ilar to that conventionally used in commercial late~ sealing compositions, for
instance 25 tc ~5%, a particular advantage of the invention is that larger amounts
of total filler may be used while still obtaining satisfactory sealing properties.
: For instance the total amount of filler, including glass beads, is generally at
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; least 20% (by volume based on the volume of rubbery polymer) and can be up to
175%, for instance 50 to 125%.
Titanium dioxide or other pigmentary filler (for instance carbon black)
generally has a particle size below 5 microns but other particulate inorganic
fillers that may be used in the invention generally have a particle size of from 1 to 50 microns. The filler should be substantially non-abrasive, so that it
does not cause wear to the machinery by which the composition is mixed and linedonto the can or o.ther end, and so materials such as crushed glass should not beused.
The preferred filler is kaolin or china clay but other fillers include
colloidal silica and other silicic fillers, synthetic silicate, calcium carbonate
or sulphate, aluminium hydroxide, talc, dolomite, or barium sulphate, zinc oxide,
~ or magnesium oxide or carbonate or silicate. Such fillers may have been surface
treated, for instance in conventional manner.
Instead of modifying the colour of the composition by including parti-
cula~e pigment some other colouring material, for instance a soluble dye, may beincluded.
The latex is based on a rubbery polymer, that is to say a polymer that,
when dried, forms a gasket that is sufficiently flexible and resistant to be cap-
100C
able of serving as a seal. Preferably the Mooney viscosity (MLl ~ ~) is generally
from 20 to 200, preferably ~0 to 160. The latex may be naturally occurring or
may be a latex made by emulsion polymerisation and thus the rubbery polymer may
be a natural polymer, for instance natural rubber, or may be a synthetic polymer.
The late~, irrespective of whether i.t is made by emulsion polymerisation or is
obtained naturally, may be diluted or concentrated before dispersing into it thefiller and a.ny other desired additives. Suitable synthet.ic rubbery polymers
include butyl rubber, polychloroprene, polyisoprene, butadiene-acrylonitrile copo-
.
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lymer, acrylonitrile-butadiene-styrene terpolyTner, polybutadiene, polyvinylidene
chloride homopolymer, polyvinylidene chloride copolymers, plasticised polyvinyl
j,
; chloride, plasticised polyvinyl acetate, polyvinyl acetate copolymers, polyvinyl-
chloride copolymers, plasticised polyvinyl propionate, polyvinyl propionate copo-
lymers, polyacrylic acid copolymers, polymethacrylic acid copolymers, acry]ic es-
ter copolymers, methacrylic ester copolymers, plasticised polystyrene, styrene-
butadiene rubbers and carboxylated styrene-butadiene copolymers. ~lends may be
used. Compositions based on vulcanisable polymers may include vulcanising agent.The preferred polylners are styrene butadiene rubbers having a styrene content of
15 to 60%, preferably 18 to 45%, by weight. They may have been made by any con-
venient polymerisation method, and thus may have been made by hot or cold polymer-
isation techniques.
Tackifier resins are generally included in latex can sealing composit-
; ions and they may be included in the compositions of the invention. However
because of the improved sealing properties obtained by the use of glass beads
satisfactory results can often be obtained without a tackifier resin in the in-
vention. Instead of using a tackifier resin a liquid plasticiser, such as white
oil or other suitable hydrocarbon oil, that softens the polymer, may be used in
amounts of for instance 1 to 60%, preferably 5 to ~0%.
Best results are generally obtained when tackifier resin is included.
Suitable materials are well known and are generally selected from synthetic hydro-
carbon or petrole-lm resins~ polyterpene resins, phenolic resin mod:ified with nat-
ural resins such as rosin or terpene, xylene formaldehyde resin and modified pro-
ducts thereof, and esterified rosins or other rosin type resins such as rosin,
hydrogenated rosin, or hardened rosin. The amount of tackifier is generally at
least 10% ~by volume of rubbery polymer~ but less than 250% and preferably less
than 220%. Generally the amount is 15% to 200%.
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The composition will contain at least one stabiliser for stabilising
the latex and the dispersion. This stabiliser may be selected from any of the
materials conven~ionally used for stabilising sealing compositions based on filled
polymer latices. Such stabilisers include styrene maleic anhydride or other sty-
rene copolymers, methyl cellulose, polyacrylamide, ethoxylate condensates, poly-
vinyl pyrolidone, ammonium oleate, and casein. Such stabilisers may be used in
admixture, for instance with other materials.
The compositions may include minor amounts, e.g. up to 1% or at most up
to 5% of other additives that are known to those skilled in the art and that are
conventional in filled latex sealing compositions, such as viscosity increasing
agents (for instance ammonium alginate, bentonite or gum karaya or high molecular
weight polyacrylic acid), bactericides, corrosion inhibitors, surfactants, anti-
oxidants (for instance phenolic or amino anti-oxidants) and pH adjustors (for
instance ammonia, primary amine~ sodium hydroxide or sodium carbonate).
The total solids content of the composition is generally from 20 to 85%
by weight, preferably 30 to 80%.
The composition may be made simply by mixing into the chosen latex
(optionally ater dilution) the tackifying resin, glass beads and any other fil-
ler, and any other additives all in conventional manner. Naturally care must be
taken to ensure that the latex does not coagulate and that a uniform dispersion
is obtained. For instance it may be desirable to form a dispersion of the filler,
including glass, and optionally also tackifier and add this stable dispersion to
the latex.
Some non-limiting examples oE the invention are now given.
In these sealing properties are identified by two sets of quantitative
values which are referred to as "biological seal" and "sterilisation extrusion".
These are recorded as follows:
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"Biological seal". The composition is lined into can closures (often
termed can ends) and dried in conventional manner, the amount of the composition
; being such as to give the dry film volume generally recommended for the particu-
lar si~e. Cans having a soldered side seam are then filled with a hot liquid
nutrient, typically at a temperature of 97C., leaving a small headspace. The
test closures are double seamed onto these filled cans whilst simultaneously
injecting staam into the headspace. The closed cans are then sterilised, typi-
cally at 121C for 30 minutes, and after stPrilisat:ion are immediately cooled in
water containing gas-producing, non-pathogenic micro-organisms capable of growth
in the aforementioned nutrient. After cooling and whilst still wet with the
cooling water, the cans are subjected to a controlled deformation at the junction
of the side seam and the double seam of the test closure. After incubation for
six days at an elevated temperature optimum for the growth of the micro-organism,
followed by one day at ambient temperatureJ the cans are examined visually and
the number of swollen cans recorded. The retained vacuum in the remaining cans
is measured. Cans having a low retained vacuum and the swollen cans are consid-
ered to have reached this-condition through failure of the seal in the test cIo-
sure. The swollen and low vacuum cans are termed failures and the "biological
seal" value is the failure rate expressed as the number of such cans per thousand
tested. Because of the procedures used the number of failed cans per thousand in
this biological seal test is of course very much greater than that which would
occur with commercially packed cans sealed with these compositions.
"Sterilisation extrusion". The composition is lined into can closures
and dried, in conventional manner, the amount of the composition being such as to
give a dry film volume approximately 20% greater than that generally recommended
with the particular closure size. Cans are filled with water at typically 70C
to leave no headspace and test closures are double seamed onto these filled cans.
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The closed cans are then sterilised typically at 130C for one hour and allowed
to cool to room temperature before examination. The number of protrusions of
compound from the double seam along the outside wall of the can body at the ~estclosure are counted, typically on a sample of 10 cans for each composition.
Large protrusions are counted as appropriate multiples of the typical, more com-monly occurring, small protrusions. The average number of protrusions per can isrecorded as the value for "extrusion". This value should be as low as possible,
preferably below 10 under the condition of the test. However, because of the
extreme conditions of the test, greater values than this are commercially toler-able.
In the following examples each composition is made by mixing together
the latex of the chosen rubbery polymer and containing minor amounts of conven-
tional additives known to those skilled in the art, stabiliser, filler, titaniumdioxide pigment, and tackifier resin (when present). Unless otherwise specified
there is 22% of a main tackifier, the amount of stabiliser is ~.2%, the amount of
- titanium dioxide is 3.2%, and the amount of filler is 30%, all based on the vol-
ume of rubbery polym~r in the latex. When the filler is kaolin the total solids
content of the composition is about 60% by weight.
In each of the examples the filler consists of the glass beads (if pre-
sent) and the stated inorganic particulate material ~if present) which generallyhas a particle size of 1 to S0 microns although titanium dioxide may have a part-
icle size of down to 0.1 microns. Unless otherwise stated the glass beads are
formed from molten soda glass and unless otherwise stated the beads have particle
sizes between 1 and 53 microns, with an average particle size of about 35 microns.
In Examples 1, 2, 3 and ~ the composition includes 22% of hydrocarbon
resin tackifier. In Examples 5 and 6 the amount oE tackifier (if present) or
substitute material is as stated.
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In examples 1 to 6 and in Examples 7aand 7b the stabiliser is styrene
maleic anhydride copolymer stabiliser but in the other compositions in Example 7
different stabilisers are used.
In each of Examples 1 to 7 the latex is a styrene butadiene latex hav-
ing a solids content of 66 to 69% by weight and containing 31 to 36% bound sty-
rene and which has been polymerised cold (at 5C) using fatty acid soaps. The
polymer in the latex has a Mooney value (as defined above) of 100 to 130. How-
ever, similar results may be obtained using other styrene butadiene latices that
may have been polymerised hot or cold such as those listed in the following table:
TypeTotalBound Mooney Emulsifier
SolidsStyrene Value
:~ % %
Cold63 29 140 Fatty acid
Cold67 34 75 Fatty acid
Cold68 30 150 Fatty acid
~Hot45 46 90 Rosin ester
Hot 42 50 30 Rosin ester
~ .
Hot 59 46 75 Rosin ester
Hot 50 46 70 Rosin ester
The hydrocarbon resin tackifier is a polymer of mixed 5-carbon alkenes
having a melting point of about 100C. In Example 8 the styrene-acrylic ester
copolymer has a minimum film forming ~emperature of 20C and a film hardness (Per-
so~) of 160 seconds. Similar results are obtainable with other styrene-acrylic
ester latices. In Example 8 the polyvinylidene chloride copolymer latex is one
having a minimum film formation temperature of 4C.
In Example 9, the latex is a styrene butadiene latex having a solids
content of 49-51% and containing 44% bound styrene which was polymerised at 55C
using rosin acid soaps, the polymer in the latex having a Mooney value as previ-
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ously defined of 60-80. This formulation is stabilised with 9 volumes of casein
and vulcanised with a 1/1/0.5 volume system of zinc oxide, ~inc dibutyl dithio-
carbamate/su:lphur. It is pigmented with 4 volumes each of titaniwn oxide and
iron oxide.
~ In example 10, the rubbery polymer is derived from a blend of two lati-
; ces, one being a latex of a polymer of 2 chloro-butadiene having a solids content
of 58%, the Defo plasticity of the polymer being 7,000 ~ l,OOQ and the Shore A
hardness about 40~ and the other the latex of a copolymer of vinyl acetate maleic
acid ester having a solids content of 54% and having a minimum film forming tem-
perature of 12C., in a dry volume ratio of 83.5/16.5 respectively. The formul-
ation is stabilised with 6.5 volumes of casein and plasticised with 5 volumes
butyl benzyl phthalate and 1.5 volumes of di-iso-octyl phthalate. The 'biologi-
cal seal' results of this example are obtained in a modified method wherein veg-
etable oil is added to the nutrient broth and no steam is injected during double
seaming.
In example 11 the rubbery polymer is derived from a blend of two lati-
ces one being a pre-vulcanised natural rubber latex having a total solids content
of 62% and the other a polychloroprene latex having a total solids of 59%, in a
dry volume ratio of 92.5/7.5 respectively. The formulation is stabilised by the
addition of 4.5 volumes of ammonium oleate.
In example 12, the rubbery polymer is derived Erom a natural rubber
latex having a solids content of 61%. Thi~ formulation is stabilise~d with 3.5
volumes of styrene maleic anhydride copolymer and contains 50 volumes of hydro-
carbon resin.
In tests 13A to 13~ of example 13, the rubbery polymer is a cold poly-
merised styrene butadiene latex having a total solids of ~7%, a bound styrene
content of 32% and a Mooney viscosity of 115. In test 13G the rubbery polymer is
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a blend of 20 parts (dry volume) of this latex with 80 parts (dry volume~ of a
hot polymerised styrene butadiene latex having a total solids of 59%, a bound
styrene content of 46% and a Mooney viscosity of 75. Both latices are stabilised
by styrene maleic anhydride copolymer.
Since the extrusion and biological seal results will vary according to,
for instance~ variable conditions under which the tests are carried out compari-
sons should, in general, be made only between results within a single example.
It is desirable that the "biological seal" and "sterilisation extrusion" values
should be as low as possible. The following exa~nples show that the inclusion of
glass beads reduces the values, thus demonstrating improved sealing, in compara-
tive compositions and that good sealing performance can be obtained even when,
for instance, the composi~ion contains widely ranging proportions of ingredients
and widely differing ingredients. All quantities are expressed as parts by volume
unless otherwise stated except tha~ the content of styrene in styrene butadiene
rubbers and the solids content of latices are expressed as percentages by weight.
Examples 1 to 4
Sterilisation
Test Filler Biological Seal Extrusion
lA 30 Kaolin 0 Glass beads 680 10.3
lB 22.5 Kaolin 7.5 Glass beads 290 1.4
`~ 20 lC 15 Kaolin 15 Glass beads 75 0.3
lD 7.5 Kaolin 22.5 Glass beads 60 0.5
lE 0 Kaolin 30 Glass beads 105 0.2
1~ 28 Kaolin 28 Glass beads 110 0.5
lG 0 Kaolin 59 Glass beads 155 0.4
lH 0 Kaolin 89 Glass beads 165 0.0
lI 0 Kaolin 30 Crushed glass 420 19.8
lJ 0 Kaolin 30 Glass Microballoons585 7.4
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Sterilisation
Test Filler Blological Seal Extrusion
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2A 30 Kaolin 0 Glass beads 225 38.6
2B 0 Kaolin 30 Glass beads 1-53~ 10 2.7
2C 0 Kaolin 30 Glass beads 45-74~ 5 24.2
2D 0 Kaolin 30 Glass beads 74-14~1 lO 23
2E 0 Kaolin 30 Glass beads 3-10~ 90 27.9
2F 0 Kaolin 30 Glass beads 1-5~1 100 33.2
2G O Kaolin 30 I.ow Soda, Type E
; Glass beads 0-44~ 10 0.1
.... . ~ _~._ . _ . ..
3A 30 Kaolin 0 Glass beads 410 25.9
3B 15 Kaolin 15 Glass beads 15 3.8
3C 30 Talc 0 Glass beads 245 30.3
3D 15 Talc 15 Glass beads 25 1.5
3E 30 Barium Sulphate 0 Glass beads210 2.0
3F 15 Barium Sulphate 15 Glass beads20 1.8
3G 30 Titanium dioxide 0 Glass beads490 10.4
3H 15 Titanium dioxide 15 Glass beads 40 5
3I 30 Calcium Carbonate 0 Glass beads 150 4.0
3J 15 Calcium Carbonate 15 Glass beads 10 2.1
3K 30 Aluminium 0 Glass beads 245 15
Hydroxide
3I. 15 Aluminium 15 Glass beads 10 0.7
~Iydroxide
3M 3Q Spherical Silica 0 Glass beads430 18.8
3N 15 Spherical Silica l5 Glass beads 40 4.0
... _ _ . ._ ... __ ~ . . .. _
4A 30 Kaolin 0 Glass beads 190 36.9
4B 0 Kaolin 30 Glass beads 5 0.9
4C 0 Kaol n 30 Crushed glass 17.
_ . . .~_ .. . . .__
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Examples 5 and 6
Biological Sterilisation
Test Filler Tackifier Seal Extrusion
5A 30 Kaolin 0 Glass beads 22 Hydrocarbon 585 0.4
: resin
5B 68 Kaolin 18 Glass beads 27 ~ 410 0.1
5C 43 Kaolin 43 Glass beads 27 " 170 0.0
5D 68 Kaolin 18 Glass beads 47 - 325 0.0
5E 43 Kaolin 43 Glass beads 47 " 145 0.0
SF 43 Kaolin 43 Glass beads 12.5 White Oil 260 0.0
5G 43 Kaolin 43 Glass beads 37.5 " 285 0.0
. . _ ~ . . _ _
~, 10 SH 30 Kaolin 0 Glass beads 22 Hydrocarbon 235 50.4
resin
.. 56.5 Kaolin 0 Glass beads 180 " 635 18.4
5J 56.5 Kaolin 24 Glass beads 180 " 310 3.4
.. ~ . __ _ _ .
5K 30 Kaolin 0 Glass beads 22 " 325
5L 104 Kaolin 10 Glass beads 8Q " 155
5M g4 20 Glass beads 80 " 130
. _.~ _ __
6A 30 Kaolin 0 Glass beadsNo tackifier 495 28.7
6B 0 Kaolin 30 Glass beads .. .. 75 2.7
- 6C 30 Kaolin 0 Glass beads~22 Methyl 180 50.6
~ester o~
6D 0 Kaolin 30 Glass beads(~hydriogenated 35 16.7
6E 30 Kaolin 0 Glass beads522 methylated 545 65.6
6F 0 Kaolin 30 Glass beads~melamine forma - 80 46.8
~dehyde resin
6G 30 Kaolin 0 Glass beads~22 pentaeryth- 710 41.2
~ritol ester o~
6~1 0 KaoIin 30 Glass beads~an alkyd resin 195 12.5
61 30 Kaolin 0 Glass beads~22 Coumarone 420 39.4
~Indene rosin
6J 0 Kaolin 30 Glass beads 60 21.5
. _ . _ ...... . _ _ _ _ '
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ExamR~e 7
Sterilisation
Test Filler StabiliserBiological Seal Extrusion
. _ ___ . _ . ._
7A30 Kaolin0 Glass fstyrene maleic 315 38.1
Beads ~anhydride copolymer
7B 0 Kaolin30 Glass ~ 15 15.5
Beads -
7C 30 Kaolin0 Glass rcasein ~ith sulphonate 420 67
Beads
7D 0 Kaolin30 Glass and ethoxylate stabili- 95 35.7
Beads ~sers
7~ 30 Kaolin0 Glass polyacrylamide 260 61.6
Beads
7F 0 Kaolin30 Glass 50 27
Beads
7G 30 Kaolin0 Glass rethoxylate condensate~95 77.0
Beads
7~1 0 Kaolin30 Glass 135 37.8
Beads _
7I 30 Kaolin0 Glass polyvinyl pyrrolidone 370 59.1
7J 0 Kaolin30 Glass ~ 35 18.5
Beads ~
7K 30 Kaolin0 Glass ~~ammonium oleate 805 65.5
Beads
7L 0 Kaolin30 Glass ~65 3~.6
Beads ____ ___ _ _
Example 8 BiologicalSterilisation
Test Filler Rubbery co~y~ Seal _ Extr~ ion
8A 30 Kaolin0 Glass ~styrene acrylic 375 20.
beads ~ copolymer
8B0 Kaolin 30 Glass ~ 25 1.8
beads (
8C30 Kaolin 0 Glass ~olyvinylidene 590 6.
beads chloride
-~ 20 8D0 Kaolin 30 Glass 65 12.9
beads _ _ __
_ . ... _ _
~xample 9 (vulcanised styrene-bu-tadiene polymer)
Sterilisation
Test Piller Biological Seal Extrusion
. _.
9A23 Kaolin 0 Glass beads 55 3.7
940 laolin 3 Glass beads ~ _ _ _ _
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Example 10 (2-chlorobutadiene polymer and vinylacetate-maleic acid ester copoly-mer~
Test Filler Biological Seal
lOA 8 Titanium Dioxide~ 27.5 Kaolin 0 Glass beads 185
lOB 8 Titanium Dioxide 0 Kaolin 27.5 Glass beads 25
..
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~; Example 11 (natural rubber and polychloroprene)
Sterilisation
TestFiller ~ Biological Seal Extrusion
llA71 Kaolin 0 Glass beads 125 9.0
llB35.5 Kaolin 35.5 Glass beads 5 0
llC0 Kaolin 71 Glass beads 10 0
_ _ _ ._ _ , .. . __ _~
Exam~ 12 (natural rubber)
Sterilisation
TestFiller Biological Seal Extrusion
. __ . ._ . _ _
12A 68 Kaolin 0 Glass beads 135 0
12B 68 Kaolin 24 Glass beads 55 0
_ _ . .. ~ . _~ ..
Example 13
Biological Sterilisation
Test Filler Tackifier Seal_ _ _ Extrusion _
13A beads 102 Hydrocarbon resin 150 3.4
13B 70 Kaolin 24 Glass 51 " 160 0.4
beads
13C 70 Kaolin 24 Glass 153 ~ 250 23.0
13D 93 Kaolin 24 Glass 153 " 215 8.8
beads
13E 70 Kaolin 24 Glass 204 " 185 33.9
beads
13F 93 Kaolin 24 Glass 204 " 225 17.3
beads
13G 30 Kaolin 0 Glass 22 " 205 30.6
~ beads
., _ _ . __
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