`l
`
`3,245,566
`Patented Apr. 12, 1966
`
`3,245,566
`CLOSURE CAP WITH PHENOLIC RESIN AND BU(cid:173)
`TADIENE-ACRYLONITRILE COPOLYMER MOD(cid:173)
`IFIBD VINYL PLASTiSOL RESIN GA§KET
`Paul J. Szalay, Toledo, Ohfo, assignor to Owens-minois 5
`Glass Company, a corporation of Ohio
`No Drawing. Filed May 17, 1963, Ser. No. 2lH,363
`13 Claims.
`(C!. 215-40)
`
`2
`shelf life of packaged goods and, moreover, results in a
`closure cap which will not form a hermetic seal when
`reapplied to protect the unused portion of the container
`contents.
`A further drawback of the known plastisol gasket com-
`positions is their poor impact resistance. When con(cid:173)
`tainers fitted with closure caps containing plastisol gaskets
`are packaged or handled in distribution from the manufac(cid:173)
`turer to the final consumer, the containers are often jarred
`10 or bumped against each other or against the caps of ad(cid:173)
`joining containers. These impacts cause certain changes
`in the dimensions of the plastisol gasket and, if the gasket
`material has poor resiliency, it will fail to return to its
`original dimensions and hence leakage results from the
`15 failure of the gasket material. Similarly, the impact may
`cause a break or crevice between the gasket and the
`closure cap, permitting air to leak into the container thus
`impairing the seal and spoiling the product. The leakages
`will produce not only ,contamination of the product but
`20 loss of material as well.
`A further characteristic of many of the plastisol gasket
`compositions of the past has been their susceptibHity to
`seizing up in place, often making it necessary for the con(cid:173)
`sumer to apply excessive torque to remove the cap. This
`25 phenomenon is physical in nature and occurs because of
`the poor aging characteristics of vinyl plastisols. The
`friction between the plastisol gasket and the container
`increases rapidly with standing. While the torque re(cid:173)
`quired to open the container immediately after sealing
`30 may be low, namely, in the range of from 5 to 25 inch
`pounds, it may increase after one day to 35 to 50 inch
`pounds. The ideal range for torque removal has been
`found to be from about 15 to 25 inch pounds regardless
`of the interval of time between initial capping and re(cid:173)
`moval.
`It is, accordingly, the object of this invention to avoid
`the shortcomings and disadvantages ,of the prior-known
`plastisol gasket materials for closure caps.
`It is a further object of this invention to provide a
`novel plastisol gasket for closure caps.
`It is a further object of the present invention to provide
`plastisol gaskets for closure caps which have improved
`resiliency and impact resistance, thus assuring a hermetic
`seal between the cap and the container.
`It is a still further object of the present invention to
`provide a sealing gasket which permits low removal torque
`of the closure cap particularly when the contents of the
`container are sealed under vacuum.
`In attaining the above objects, one feature of the pres-
`50 ent invention resides in ,the incorporation of particular
`ingredients in a plastisol composition to produce improved
`resiliency and impact resistance of a gasket formed there(cid:173)
`from.
`A further feature of the present invention resides in
`55 the plastisol composition :containing a liquid copolymer
`and a phenolic resin to improve the resiliency and impact
`resistance of the gasket formed therefrom.
`These and other objects and features will become ap(cid:173)
`parent to those skilled in the art from the following de-
`60 tailed description of the present invention.
`It has now been discovered that a plastisol gasket com(cid:173)
`position of the "flow-in" type can be produced possessing
`good resiliency and impact resistance characteristics by
`the incorporation therein of particular polymers. The
`65 resulting closure caps containing the plastisol gasket of
`this invention can be removed from the container with a
`relatively low removal torque regardless of the lapse of
`time after the initial capping operation.
`It has been found
`that by incorporating a liquid
`butadiene-acrylonitrile copolymer together with a phe(cid:173)
`nolic resinoid of the novolak type in a plastisol gasket
`
`70
`
`The present invention relates to improved plastisol
`gasket compositions and closures containing gaskets made
`from such compositions. More particuJa.rly, the invention
`relates to flow-in vinyl chloride plastisol gaskets as sealing
`means for container closures.
`Many items today which are packaged in containers are
`susceptible to deterioration in quality unless packaged in
`hermeticaUy sealed containers. This method of packaging
`is particularly important with respect to food products
`where it is desirable to employ a closure cap which will
`form a hermetic seal when the goods are initially sealed
`and is capable of being reapplied to form a hermetic seal
`to protect the unused portion of the contents.
`Various types ,of closure caps have been employed in
`the past for providing he,rmetically sealed containers.
`Much of the work in this area has gone into improving the
`ability to apply and form a seal that will cooperate with
`the rim of the container and prevent the entrance of air
`into the container, so as to permit maximum storage time
`or shelf life for the contents of the container without
`spoilage.
`One method for hermetically sealing containers which
`has become widely employed is the use of so-called "flow-
`in" type gaskets which are formed by flowing a material
`with a paste01ike consistency into the closure and baking
`the gasket to make it .firm. These flowable materials con(cid:173)
`tain synthetic resins, plasticizers, fillers and the like and
`are known as "plastisols" in the art. Plastisol gaskets have
`been employed with a wide variety of closures, including
`rotatable closure caps for use particularly with glass con(cid:173)
`tainers.
`In most cases the rotatable closure cap consists of a
`metal shell with a top panel portion and a depending skirt
`portion. The plastisol gasket composition is "flowed in"
`around the outer edge of the inner surface of the top panel
`portion, and may extend down the depending skirt par- 45
`tion. The top rim or edge of the container is pressed into
`this plastisol gasket when the cap is forced down into
`sealed relation with the container. The closure cap is
`provided with inwardly directed lugs attached to the de(cid:173)
`pending skirt portion, whence comes the name "lug type"
`closure. The lugs on the closure are slidingly moved
`along threads or lugs formed in the outer rim along the
`top edge of the container. To seal the container, the clo(cid:173)
`sure cap is rotatably advanced onto the container, bring(cid:173)
`ing the gasket into contact with the upper rim of the con(cid:173)
`tainer.
`In many canning operations, the containers to(cid:173)
`gether with the contents are subjected to elevated temper(cid:173)
`atures for a period of time, so that the cap and the gasket
`therein must withstand such temperatures.
`The plastisol gasket materials which have been em(cid:173)
`ployed in the past are dispersions of vinyl resins in non(cid:173)
`·volatile plasticizers which have the consistency of a paste.
`At higher temperatures the paste becomes gel-like and loses
`its fluidity. The change in physical properties is brought
`about by solution of the resin in the plasticizer as the
`temperature is increased. At about 175° C. fusion takes
`place, resulting in a tough, rubbery mass.
`Although these plastisol gaskets have been extensively
`used, a number of drawbacks have been associated there(cid:173)
`with. One serious problem is the rapid loss of gasket
`resiliency. This severely limits the maximum storage or
`
`35
`
`40
`
`RJRV EX 1015
`Page 1
`
`
`
`3,245,566
`
`4
`3
`composition, the resulting plastisol gasket will be charac(cid:173)
`have been found suitable, although other conventional
`terized by improved resiliency and impact resistance.
`plasticizers can be used for this purpose.
`Included are
`The plastisol composition which is employed for the
`dioctyl phthalate and other dialkyl esters of dicarboxylic
`acid, such as bulyl decyl phthalate, octyl decyl phthalate,
`purposes of the present invention is in the form of a
`paste-forming resin-plasticizer mixture containing a finely
`5 dioctyl sebacate, dibutyl sebacate, dioctyl adipate, dioctyl
`azelate, diisobutyl adipate, and other plasticizers such as
`divided. synthetic resin suspended in non-volatile plasti(cid:173)
`cizers for the resin, the resin being paste-forming with
`butyl benzyl phthalate, tricresyl phosphate, polyethyl(cid:173)
`the plasticizers at a temperature below the fluxing tem(cid:173)
`ene glycol adipate, alkyl esters of higher fatty acids and
`perature of the resin plasticizer component and soluble
`mixtures of two or more plasticizers, or one or more pri-
`in the plasticizer upon heating to the fluxing tempera(cid:173)
`10 mary plasticizers with one or more secondary plasticizers.
`ture. The plastisol composition may further contain
`A plastirnl composition which contains a polymeric
`finely divided filler and pigment material as well as
`ester-epoxide plasticizer of a relatively high molecular
`stabilizers in a uniform distribution.
`weight is preferred since this contributes good stability
`The liquid butadiene-acrylonitrile copolymer contains
`and good oil, water, and heat resistance to the gasket
`from about 20% to about 40% by weight of acrylonitrile
`15 which is formed. The dibutyl sebacate is preferred as
`in polymerized form.
`the dialkyl carboxylic acid ester plasticizer because it is
`A particularly useful liquid copolymer for the pur(cid:173)
`completely odorless, non-toxic, and has good plasticizing
`pose of this invention contains about 37% by weight
`effect on polyvinyl chloride in that it produces low tem(cid:173)
`acrylonitrile in polymerized form. While the amount
`perature flexibility. Ordinarily, the total amount of
`of liquid copolymer employed will be that which is suf(cid:173)
`20 plasticizer employed is not critical provided a sufficient
`ficient to impart the desired properties to the plastisol
`amount is used to form a nlastisol of suitable viscosity.
`gasket, use of about 1 % to about 5% by weight based
`Amounts varying from abo'iit 30% to 150% by weight
`on the weight of the vinyl resin, is suitable, and use of
`based on the weight of vinyl resin are satisfactory, while
`about 3 % to about 4% by weight gives excellent results
`amounts of about 50% to 90% are preferred.
`The phenolic resinoid component of the plastisol com- 25
`It is also desirable to employ a filler material in the
`position is a two-step novo!ak resin. The novolaks are
`form of finely divided discrete particles which are uni(cid:173)
`produced from
`the reaction of less
`than equivalent
`formly distributed throughout the plastisol composition.
`amounts of formaldehyde with phenol, about 1: 08 mole
`The preferred filler matePial is titanium dioxide which
`ratio although this can be varied in an acid catalyzed re(cid:173)
`functions both as a pigment and as a lubricant. How-
`action. Novolak resins with an average molecular weight 30 ever, other filler materials such as barytes, talc, calcium
`of up to about 1200 can be used although those resins
`carbonate, clay such as bentonite, calcium silicate, carbon,
`in the medium molecular weight range, e.g. 650 amu,
`finely divided silica, and diatomaceous earth inay also
`have been found to be particularly useful for this pur(cid:173)
`be utilized. Other pigments can also be added if desired
`pose. An example of the two-step phenolic novolak used
`to ,impart any desired color, and for opaqueness. Up to
`for this purpose is that which is sold under the designation
`35 about 20% or more filler may be added, although as little
`BRP 5012 by Union Carbide Corp. The phenolic novolak
`as about 0.5% based on the weight of vinyl chloride resin
`will be completely cured during the baking cycle for the
`is preferably employed.
`gasket. The· amount of phenolic novolak resin employed
`It is customary to employ a stabilizer for the plastisol
`will be that which is sufficient to impart the desired prop(cid:173)
`gasket composition, and preferably one that is non-toxic
`erties to the plastisol gasket. Use of about 1 % to about
`40 if the gasket and closure are to be used for food con(cid:173)
`5% by weight, based on the weight of the vinyl resin, has
`tainers. Calcium-zinc stabiiizers, such as that sold com(cid:173)
`been found to give satisfactory results, while amounts
`mercially as Mark 34 by Argus Chemical Corporation
`of about 2% to about 4% are generally preferred.
`of Brooklyn, N.Y., and Synpron 216 sold by Synthetic
`Excellent properties are obtained by incorporating the
`Products Co. of Cleveland, Ohio, have been found to yield
`above two polymers into the plastisol whereby the gasket
`45 good results. These are calcium-zinc soaps of higher
`materials produced from the plastisol compositions are
`fatty acids in the stearic range; that is, acids having from
`able to withstand impact and possess improved recovery
`16 to 22 carbon atoms. However, other materials func(cid:173)
`properties to prevent leakage and contamination of the
`tioning as stabilizers for vinyl chloride resin can also be
`contents of the container.
`used.
`Included are materials such as thio-organic tin
`In forming the plastisol gasket composition, any of the
`50 compounds, metallic soaps, such as calcium, aluminum
`numerous, commercially available vinyl chloride resins
`and zinc stearates, calcium laurate, barium laurate, mag(cid:173)
`may be employed, preferably polyvinyl chloride of a high
`nesium stearate, alkyl and aryl tin compounds, dibutyl tin
`molecular weight in the range of about 60,000 to about
`oxide, trioctyl phosphite, and the like. When used with
`90,000, although higher molecular weights can also be
`processed food containers, it is important to employ a
`employed. The polyvinyl chloride resin can be mixed
`55 non-toxic material. Sufficient amounts of stabilizer are
`with other vinyl polymers and copolymers. Copolymers
`used to achieve the desired stabiHzing effect, from about
`of vinyl chloride with a minor amount of copolymeriz(cid:173)
`0.4% to 1 % based on the weight of the vinyl resin is
`able ethylenically unsaturated monomer can also be em(cid:173)
`usually adequate.
`plpyed. Generally, a high percentage of the vinyl chlo(cid:173)
`The viscosity and flow characteristics of the composi-
`ride must be present to obtain the high impact resistance,
`60 tion of the present invention may be modified by adding
`e.g., at least about 80% vinyl chloride.
`Included in the
`thereto a thinning agent such as an aliphatic or an ali(cid:173)
`group of suitable comonomers are vinyl acetate, vinyl(cid:173)
`phatic-aromatic hydrocarbon including mineral spirits,
`idene, .chloride, dialkyl maleates, maleic anhydride, and
`cyclohexane, and other petroleum distillates.
`the like.
`It is understood that mixtures of comonomers
`The plastisol gasket composition of this invention is
`can be employed provided the vinyl chloride is present
`65 made by blending the ingr,edients together in the usual
`in the amount of at least 80%.
`mixing devices used for this purpose, for a sufficient time
`The vinyl resin is uniformly distributed in and forms
`to produce the uniform, stable plastisol composition con(cid:173)
`a paste with a plasticizer in which the resin ,is essentially
`taining the liquid butadiene acrylonitrile copolymer and
`insoluble at room temperature. At elevated tempera(cid:173)
`70 the phenolic novolak.
`tures, the resin is more soluble and dissolves in the hot
`When used for processed food closure caps, the plastisol
`plasticizer, resulting in a tough, rubbery mass.
`gasket must possess processing temperature resistance, be
`An suitable plasticizer may be utilized as long as it
`odor-free, non-toxic, and must not impart any flavor to the
`is non-volatile and, when used for containers of food
`contents. The gasket composition of the present invention
`products, is non-toxic. Plasticizers such as polymeric
`7 5 possesses these characteristics as well as good resiliency
`ester-epoxides (Paraplex G-62) and acetyl tributyl citrate
`
`RJRV EX 1015
`Page 2
`
`
`
`3,245,566
`
`5
`and impact resistance, and is further characterized by low
`removal torque.
`An additional advantage of the plastisol gasket compo(cid:173)
`sitions of the present invention resides in the fact that
`complex milling procedures are not required. In carrying 5
`out the mixing operation, it is preferred to blend the
`ingredients briefly in a mixer such as a Hobart planetary
`action mixer. From ½ to ¾ of the mixed wet ingredi(cid:173)
`ents are added to the blend and mixing is continued for
`a few minutes at low speed. The mixing is increased to 10
`medium speed for 5 minutes, and to high speed for 10
`minutes. The remaining wet ingredients are added to the
`mixture, and the ingredients are mixed for 5 minutes at
`high speed. Mixing is completed at low speed for about
`10 minutes, and this sufficiently relieves the mixture of en- 15
`trained air. If necessary, the mixing bowl may be cooled
`and the mixing times can be varied. Generally, 30 min(cid:173)
`utes of mixing is sufficient to insure a uniform product.
`It is preferable that the temperature of the mixing does
`not rise above about 35° C.
`The following examples will serve to illustrate the pres(cid:173)
`ent invention, but are not to be construed as limiting the
`scope of ihe invention in any manner.
`
`6
`tion B contained no liquid butadiene-acrylonitrile copol(cid:173)
`ymer. The compositions contained the following in(cid:173)
`gredients in parts by weight:
`
`Example I
`
`A
`
`B
`
`Polyvinyl chloride ____________________ _
`Phenolic novolak ______________________ _
`Liquid butadiene-acrylonitrile copoly-
`mer ___ -------------------------------
`Polymer ester epoxide plasticizer_ _____ _
`Dibutyl sebacate ______________________ _
`Titanium dioxide ______________________ _
`Calcium-zinc stabilizer ________________ _
`
`100
`2
`
`4
`50
`4
`1
`0. 5
`
`100
`
`4
`50
`4
`1
`o. 5
`
`100
`2
`
`50
`4
`1
`o. 5
`
`The compositions of A and B were applied to the same
`conventional lug-type closure cap as employed in Exam(cid:173)
`ple I. Physical test data were taken measuring the
`tensile strength of the plastisol gasket and the percent re(cid:173)
`covery after being subjected to a deformation. The defor-
`ZO mation was carried out by compressing the gasket to 50%
`of its total original thickness employing a hard, round
`object for this purpose. The deformation was applied for
`one minute after which the gasket was released. The
`gaskets expanded to recover a portion of their original
`dimensions and the thickness was measured at the point
`where the deformation was applied. The values in Table
`I represent the percent of the thickness recovered after
`release. The percent recovery is thus an indication of the
`resiliency of the gasket material. The results are tabu(cid:173)
`lated below and demonstrate that the gaskets of this in(cid:173)
`vention have improved tensile strength and resiliency.
`
`25
`
`30
`
`EXAMPLE I
`A plastisol composition was prepared containing
`following ingredients in parts by weight:
`Parts high molecular weight polyvinyl chloride
`(QYKV-2) -------------------------------
`Parts phenol-formaldehyde novolak with a molecular
`weight of about 650 amu (BRP 5012) _________ _
`Parts butadiene-acrylonitrile liquid copolymer con(cid:173)
`taining about 37% by weight of acrylonitrile in
`polymerized form (Hycar 1312) _____________ _
`(Paraplex G-
`Parts polyester-epoxide plasticizer
`62) --------------------------------------
`Parts dibutyl
`sebacate plasticizer
`(Monoplex
`DBS) ------------------------------------
`Part titanium dioxide --------------------------
`Part calcium-zinc stabilizer (Synpron 216) _______ _
`
`the
`
`100
`
`2
`
`4
`
`50
`
`The ingredients above were blended for 30 minutes using a
`Hobart mixer at room temperature. The resulting paste
`was applied to conventional lug-type closure caps to form
`"flow-in" gaskets which exhibited improved recovery,
`tensile strength and impact resistance as shown in Tables
`I and II, infra.
`
`EXAMPLE II
`
`A plastisol gasket composition was made containing
`the following ingredients in parts by weight:
`
`Parts high molecular weight polyvinyl chloride
`(QYKV-2) ------------------------------- 100
`Parts phenol-formaldehyde novolak with a molecular
`weight of about 650 amu (BRP 5012) __________
`Parts butadiene-acrylonitrile liquid copolymer con(cid:173)
`taining about 37% acrylonitrile in polymerized
`form (Hycar 1312) -------------------------
`Parts polyester-epoxide plasticizer (Paraplex G-
`20
`62) --------------------------------------
`Parts dibutyl sebacate -------------------------
`34
`1
`Part titanium dioxide --------------------------
`Part calcium-zinc stabilizer ____________________ 0.8
`
`4
`
`5
`
`The ingredients were blended in a Hobart mixer for ap(cid:173)
`proximately 30 minutes. Thereafter the resulting paste
`was applied to conventional lug-type closure caps by the
`"flow-in" method. The caps showed good properties of
`impact resistance and improved removal torque.
`
`EXAMPLE III
`
`For purposes of comparison, two plastisol compositions
`identified as A and B were compounded and were iden(cid:173)
`tical with that of Example I with the exception that com(cid:173)
`position A contained no phenolic novolak and composi-
`
`4
`1
`0.5 40
`
`35
`
`Table I
`
`__ _ ___ ,_
`I Example I
`Tensile strength in p.s.L_ --------------1
`Rrgi~~WoR~r_c~~~~ ~!:~~ _1_ ~!~1~~~ ~! -~~:-
`
`A
`
`828
`
`42.1
`
`1,940
`
`47.4
`
`B
`
`1,740
`
`38. 5
`
`45
`
`50
`
`GO
`
`Further tests were carried out in order to assess the
`impact resistance of closure caps containing gaskets pro(cid:173)
`duced from l!he plastisol compositions of the present in(cid:173)
`vention a•s compared with plastisol gasket materials
`representative of those which are commercially available
`Im(cid:173)
`identified as Plastisol Gasket A, Table II, infra.
`pact resistance of the two groups of closure caps and
`gaskets was measured by filling the containers with water
`and placing the caps thereon wioh the contents being
`under vacuum. The containers were kept upside down
`and the cap closures subjected to an impact on the shoul(cid:173)
`der portion of the cap, i.e., between the top panel and
`depending skirt portion of the cap. The impact was
`provided by an impact tester comprising a rod with a
`55 small weight at one end and positioned to pivot in an
`arc about a point so that the weight struck the shoulder
`of the cap. Each cap was struck by the weight once
`on the shoulder portion adjacent each of its four Jug
`positions, and then struck once on l!he shoulder portion
`in ,the ,area between 1wo lug positions. After each blow,
`the water in the container was observed for bubble forma(cid:173)
`If a single bubble was observed, it indicated that
`tion.
`the seal was momentarily broken and then sealed again.
`Such a gasket iis still deemed to provide a satisfactory
`If a continuous stream of bubbles was formed, the
`05 seal.
`gasket had failed to maintain a good seal and had ex(cid:173)
`posed the contents to the atmosphere.
`For purposes of measuring impact resistance, the arm
`of the impact tester was started at an arc of 65 ° and
`70 if no failure occured after the eight blows on the shoul(cid:173)
`der at the above-described positions, the arc was in(cid:173)
`creased to 7 5 °, then 85 °, and up to 90 °, on each con(cid:173)
`tainer, until leakage and failure occurred. T:he results
`are set forth in Table II, with 8 closure caps and gaskets
`75 being tested for each of the two groups.
`
`RJRV EX 1015
`Page 3
`
`
`
`7
`Table II
`
`Number of failures at-
`
`3,245,566
`
`Gaskets
`goo
`g50
`75°
`65°
`- - - - - - - - - - - - - - -1 - - - - - - - -
`Example L _________________________________ _
`0
`0
`0
`0
`Polyvinyl Chloride Plastisol Gasket ________ _
`0
`8 ------ ------
`
`8
`vinyl chloride plastisol gasket, said parts by weight being
`based on 100 parts by weight of vinyl chloride resin in
`said plastisol.
`4. In a closure cap in sealed relation with a container
`5 and having a vinyl chloride plastisol gasket disposed
`therein, and where said gasket has poor impact resist(cid:173)
`ance and ,resiliency causing leakages and loss of vacuum
`in the container when the closure cap is subjected to im(cid:173)
`pact, the improvement in accordance with which leakages
`It will be noted that the ga,skets of the present in- 10 and loss of vacuum are substantially eliminated when
`the closure cap is subjected to impact and which comprises
`vention did not leak after an impact of 90 °, while those
`which represent the conventional commercial gasket
`having about 4 parts by weight of a liquid butadiene-
`failed at an impact of only 75°, as measured by the im-
`acrylonitrile copolymer containing from ,about 20% to
`pact tester.
`about 40% by weight of acrylonitrile in copolymerized
`Thus, the data demonstrates that closure caps provided 15 fmm and about 2 parts by weight of a phenol-formalde-
`with the plastisol gasket of the present invention is able
`hyde novolak copolymer present in said vinyl chloride
`to withstand substantially increased impacts without the
`plastisol gasket, said parts by weight ,being based on
`seal being deleteriously affected.
`100 parts by weight of vinyl chloride resin in said plasti-
`It is understood that varfous other modifications will
`sol.
`5. In a closure cap having a vinyl chloride plastisol
`be apparent to and can readily be made by those skilled 20
`in the art without departing from the scope and spirit
`gasket disposed therein and wherein said gasket has
`of this invention. Accordingly, it is not intended that
`poor impact resistance and resiliency causing a deteriora-
`tion of the seal when said closure cap is in sealed re-
`the scope of the claims appended hereto be limited to
`the description set forth herein but rather that the claims
`lation with a container and subjected to impact, the im-
`be construed as encompassing all the features of patent- 25 provement whereby the impact resistance and resiliency
`are improved and which comprises having from about 1
`able novelty whfoh reside in the present invention includ-
`to 5 parts by weight of a liquid butadiene-acrylonitrile
`ing all features which would be treated as equivalents
`thereof by those skilled in the art to which the invention
`copolymer containing about 20% to about 40% acrylo-
`pertains.
`nitrile by weight in polymerized form ,and about 1 to
`What is claimed is:
`SO 5 parts by weight of a phenol-formaldehyde novolak co-
`l. In a closure cap in sealed relation with a container
`polymer present in said vinyl ohloride plastisol gasket,
`and having a vinyl chloride plastisol gasket disposed there-
`said copolymers being present together in an amount
`in, and where said gasket has poor impact resistance
`sufficient to improve the impact resistance and resiliency
`and resiliency causing leakages and loss of vacuum in
`of said gasket, said parts by weight being based on 100
`the container when the closure cap is subject to impact, 35 parts by weight of vinyl chloride resin in said plastisol.
`the improvement in accordance with which the leakages
`6. The closure cap as defined in clmm 5 wherein said
`and loss of vacuum are substantially eliminated when the
`liquid butadiene-acrylonitrile copolymer is present in an
`closure cap is subjected to impact and which comprises
`amount to about 3 -to 4 parts by weight of said vinyl
`having from about 1 to 5 parts by weight of a liquid
`chloride resin in said gasket.
`butadiene-acrylonitrile copolymer and about 1 to 5 parts 40
`7. A closure cap having a vinyl chloride plastisol
`by weight of a phenol-formaldehyde novolak copolymer
`gasket disposed therein, said gasket having a composition
`present in said vinyl ohloride plastisol gasket, said co-
`comprising a vinyl chloride dispersion resin and from
`polymers being present together in an amount sufficient
`about 1 to 5 parts by weight of a liquid butadiene-acryloni-
`to improve the impact resistance and resiliency of said
`trile copolymer and from about 1 to 5 parts by weight of
`gasket, said parts by weight being based on 100 parts 45 a phenol-formaldehyde novolak copolymer in said plas-
`by weight of vinyl chloride re'Sin in said plastisol.
`tisol, said parts by weight being based on 100 parts by
`2. In a closure cap in sealed relation with a container
`weight of vinyl chloride resin in said plastisol.
`and having a vinyl chloride plastisol gasket disposed
`8. A closure cap having a vinyl chloride plastisol
`therein, and where said gasket has poor impact resist-
`gasket disposed therein, said gasket having a composition
`ance and resiliency causing leakages and loss of vacuum 50 comprising a polyvinyl chloride dispersion resin and about
`in the container when the closure cap is subjected to
`1 to 5 parts by weight of a liquid butadiene~acrylonitrile
`impact, the :iimprovement in accordance with which the
`copolymer containing from about 20% to ,about 40% by
`leakages and loss of vacuum are substantially eliminated
`weight of acrylonitrile in polymerized form and about
`when the closure cap is subjected to impact and which
`1 to 5 parts by weight of a phenol-formaldehyde novolak
`comprises having from about 1 to 5 parts by weight of 55 copolymer in said plastisol, said parts by weight being
`based on 100 parts by weight of vinyl chloride resin in
`a
`liquid butadiene-acrylonitrile copolymer containing
`from about 20% to about 40% by weight of acrylo-
`said plastisol.
`nitrile in copolymerized form and about 1 to 5 parts by
`9. A closure cap having a vinyl chloride plastisol
`weight of a phenol-formaldehyde novolak copolymer pres-
`gasket disposed therein, said gasket having a composition
`ent in said vinyl chloride plastisol gasket, said parts 60 comprising a polyvinyl chloride dispersion resin and
`from about 3 to 4 parts by weight of a liquid butadiene-
`by weight being based on 100 parts by weight of vinyl
`-ohloride resin in said plastisol.
`acrylonitrile copolymer containing from about 20% to
`3. In a closure cap in sealed relation with a container
`about 40% by weight of acrylonitrile in polymerized form
`and 2 to 4 parts by weight of a phenol-formaldehyde
`and having a vinyl chloride plastisol gasket disposed
`therein, and where said gasket has poor impact resist- 65 novolak copolymer in said plastisol, said parts by weight
`ance and resiliency causing leakages and loss of vacuum
`being based on 100 parts by weight of vinyl chloride resin
`in the container when the closure cap is subjected to
`in said plastisol.
`impact, the improvement in accordance with whioh the
`10. A closure cap having a vinyl chloride plastisol
`leakages and loss of vacuum are substantially eliminated
`gasket disposed therein, said gasket having a composition
`when the closure cap is subjected to impact and which 70 comprisirng 100 parts by weight polyvinyl chloride dis-
`persion resin, from about 1 to 5 parts by weight of a
`comprises having about 3 to 4 parts by weight of a liquid
`butadiene-acrylonitrile copolymer containing from about
`liquid butadiene-acrylonitrile copolymer containing from
`20% to about 40% by weight of ,acrylonitrile in copo-
`about 20% to about 40% by weight of acrylonitrile in po-
`lymerized form and about 2 to 4 parts by weight of a
`lymerized form, about 1 to 5 parts by weight of a phenol-
`phenol-formaldehyde novolak copolymer present in said 75 formaldehyde nov:olak copolymer and from about 50 to
`
`RJRV EX 1015
`Page 4
`
`
`
`3,245,566
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`10
`Polyvinyl chloride dispersion resin _____________ _
`Liquid butadiene-acrylonitrile copolymer 1 _______ _
`Phenol-formaldehyde copolymer (novolak) _____ _
`Polymeric ester epoxide plasticizer _____________ _
`5 Dibutyl sebacate ----------------------------(cid:173)
`Titanium dioxide -----------------------------
`Calcium-zinc stabilizer ______________________ _
`
`9
`90 parts by weight of a plasticizer for said polyvinyl
`chloride.
`11. A closure cap having a vinyl chloride plastisol
`gasket disposed therein, said gasket having a composition
`in parts by weigiht comprising
`Vinyl chloride dispersion resin _______________
`100
`Liquid butadiene-acrylonitrile copolymer ______
`1-5
`Phenol-formaldehyde copolymer (novolak) ____ ,
`1-5
`Polymeric ester epoxide plasticizer ____________ 20-70
`Dialkyl ester of a dicarboxylic acid plasticizer ___ 2-40 10
`12. A closure cap having a vinyl chloride plastisol
`gasket disposed therein, said gasket having a composition
`in parts by weight comp