United States Pateia (19)
`Brenner et al.
`
`11)
`45
`
`4,181,780
`Jan. 1, 1980
`
`73) Assignee:
`
`54) THERMOPLASTIC HONOMER FOAMS
`Douglas Brenner, Livingston; Robert
`75 inventors:
`D. Lundberg, Bridgewater, both of
`N.J.
`Exxon Research & Engineering Co.,
`Florham Park, N.J.
`21 Appl. No.: 1,317
`(22
`Filed:
`Jan. 5, 1979
`Related U.S. Application Data
`Division of Ser. No. 855,727, Nov. 29, 1977, Continua
`tion-in-part of Ser. No. 839,172, Oct. 4, 1977.
`51) Int. Cl. ................................................ C08J 9/00
`52 U.S. C. ............................. 521/93; 260/31.2 MR;
`260/31.2 R; 260/32.4; 260/32.6 A; 260/33.6
`AQ; 260/33.6 UA; 260/42.33; 260/42.35;
`260/42.37; 260/42.38; 521/82; 521/91; 521/92;
`521/94; 521/95; 521/97; 521/140,521/150;
`521/153; 521/905
`58 Field of Search ................... 521/93, 140, 150, 94,
`521/95
`
`60
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`8/1968 Dickerson ....................... 260/30.6R
`3,396,136
`6/1974 Makowski et al.
`... 260/30.6R
`3,821, 148
`6/1974 Makowski ..........
`... 260/30.6R
`3,821, 149
`3,842,154 10/1974 Lundberg et al. ................... 264/294
`3,847,854 1 1/1974 Canter et al. ......
`260/23.7 M
`
`
`
`3,852,096 12/1974 Lundberg et al. ............. 260/31.8 M
`3,867,319
`2/1975 Lundberg ......................... 260/2.5 H
`3,870,662
`3/1975 Lundberg .............
`... 260/2.5 H
`3,870,841
`3/1975 Makowski et al. ...
`... 260/23.7 R
`3,925,280 12/1975 Lundberg et al.................. 260/23 R
`3,939,242
`2/1976 Lundberg et al.................... 264/294
`3,947,387
`3/1976 Lundberg .........
`... 260/2.5 R
`3,974,240
`8/1976 Bock et al. ........
`... 260/897 B
`3,974,241
`8/1976 Lundberg et al.
`... 260/897 B
`4,014,831
`3/1977 Bock et al. ........................ 260/23 H
`Primary Examiner-Morton Foelak
`Attorney, Agent, or Firm-Richard E. Nanfeldt
`57
`ABSTRACT
`This invention relates to a novel elastomeric foamed
`material which has been found to exhibit a variety of
`unusual and desirable features both in its physcial prop
`erties and in its process of manufacture. These foamed
`compositions of a lightly sulfonated elastomeric gum
`contain a non-volatile polar plasticizer and preferably
`extenders such as oil and fillers. These elastomer foams
`exhibit an unusal profile of physical properties including
`extremely rapid production, melt reprocessability of
`fabricated articles, a novel memory characteristic, and
`high temperature reshaping of foamed objects while
`maintaining a good foam structure. These novel foams
`can be manufactured with relatively uniform cell struc
`tures and with small cell sizes at foam densities from
`near bulk density to less than 0.1g/cc.
`
`7 Claims, No Drawings
`
`MacNeil Exhibit 2060
`Yita v. MacNeil IP, IPR2020-01139
`Page 1
`
`

`

`THERMOPLASTICONOMER FOAMS
`
`10
`
`30
`
`40
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`This application is a continuation-in-part of copend
`ing application Ser. No. 839,172 filed Oct. 4, 1977. This
`is a division of application Ser. No. 855,727, filed
`11/29/77.
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`This invention relates to a novel elastomeric foamed
`material which has been found to exhibit a variety of
`15
`unusual and desirable features both in its physical prop
`erties and in its process of manufacture. These foamed
`compositions of a lightly sulfonated elastomeric gum
`contain a non-volatile polar plasticizer and preferably
`extenders such as oil and fillers. These elastomer foams
`20
`exhibit an unusual profile of physical properties includ
`ing extremely rapid production, melt reprocessability of
`fabricated articles, a novel memory characteristic, and
`high temperature reshaping of foamed objects while
`maintaining a good foam structure. These novel foams
`can be manufactured with relatively uniform cell struc
`25
`tures and with small cell sizes at foam densities near
`bulk density to less than 0.1 g/cc.
`2. Description of the Prior Art
`Foamed articles have represented one of the fastest
`growing markets in the polymer industry in the past 15
`years,. This growth is expected to continue, and it is
`claimed that the potential usage of foamed polymers
`could far exceed the ability of the polymer industry to
`supply the needed materials.
`The market for flexible foams is currently dominated
`35
`by chemically crosslinked polymers, for example, poly
`urethanes and sponge rubbers. The time required for
`curing these materials is costly; for example, vulcanized
`elastomer foams such as vulcanized EPDM can require
`as long as two hours or more to cure. Also, the resultant
`lack of reprocessability can be a major handicap since
`many foaming operations generate up to 25% scrap.
`The present invention relates to unique and novel
`elastomer foams which have been found to possess sev
`eral unexpected and useful characteristics. These novel
`45
`foams contain a low concentration of sulfonate groups
`which are covalently appended to the elastomeric poly
`mer backbone. These flexible ionomer foams are effec
`tively crosslinked by the physical associations of sulfo
`nate salt groups from different molecules. It has been
`found that in specified sulfonated elastomer systems
`these associations can provide a strong and tough mate
`rial at use temperatures; yet at sufficiently elevated
`temperatures these associations can be disrupted to
`enable melt flow and melt fabrication. An important
`aspect of this material as specified in this invention is
`that it contains a non-volatile polar plasticizer which
`greatly improves the flow or processability of the mate
`rial at processing temperature. The continued presence
`of the non-volatile polar plasticizer in the foam subse
`60
`quent to the foaming process is crucial for many of the
`important characteristics of these novel foams such as
`the thermal reformability, the melt reprocessability and
`the memory characteristics which are described below.
`A major advantage in the production of elastomer
`lightly sulfonated thermoelastic foams is that no post
`cure is required. This can result in a large savings in
`production time, machinery and cost. Also, no precure
`
`4,181,780
`2
`is required, and this can also make the foaming process
`less complicated and more efficient. These process ad
`vantages together with the virtues of melt reprocessa
`bility, thermal reformability, the memory characteristic,
`and the temperature insensitivity of the material during
`the foaming process make these foams extremely attrac
`tive candidates for a variety of flexible foam applica
`tions.
`The preferred sulfonated elastomeric compositions of
`the present invention are derived from elastomeric pol
`ymers having a primarily hydrocarbon backbone with
`olefinic unsaturaton, especially elastomeric polymers
`such as butyl and EPDM rubbers. Some processes for
`sulfonating such polymers are described in U.S. Pat.
`Nos. 3,642,728 and 3,836,511. Some methods for using
`polar additives to weaken the physical crosslinks at
`elevated temperature and improve processability in
`non-foamed articles of these lightly sulfonated polymers
`are included in U.S. Pat. No. 3,847,854.
`U.S. Pat. No. 3,867,319 teaches a process for foaming
`an ionic polymer using a volatile polar plasticizer. A
`preferred method of foaming taught by that patent is
`dissolving of the ionic polymer in a solvent containing a
`volatile polar plasticizer and foaming by heating at
`atmospheric pressure in an oven. That patent differs
`from the instant invention in that a non-volatile polar
`plasticizer which is a high temperature flow improver is
`specified in the instant invention and, as mentioned
`above, the non-volatile polar plasticizer is required to
`obtain the unique set of characteristics of the flexible
`foams of the instant invention. In addition, the preferred
`method of foaming taught in U.S. Pat. No. 3,867,319
`(which is described above) was found to be ineffective
`for producing statisfactory foams of the ionic elastomer
`materials considered here.
`U.S. Pat. No. 3,947,387 claims novel ionic foams
`which are produced by using a volatile polar plasticizer.
`Again, such foams lack the essential ingredient of the
`non-voltile polar plasticizer which is critical to several
`of the most important characteristics of the foam of the
`instant invention.
`U.S. Pat. No. 4,051,217, filed Nov. 17, 1971, describes
`a fabrication process for multiphased plastics which
`includes ionic plastic foams. That process deals only
`with ionomers derived from a plastic material and ex
`plicitly excludes elastomeric polymers; therefore that
`application does not bear on the instant invention which
`is concerned specifically with the novel characteristics
`of anoionic elastomer foam.
`The present invention differs from the ionic polymer
`systems disclosed in U.S. Pat. No. 3,322,734, herein
`incorporated by reference, in that the products of the
`present invention are preferably neutralized at least
`about 95%. The strong association of these fully neu
`tralized ionic polymers of the present inventions are
`weakened at elevated temperatures by the addition of
`suitable plasticizing agents which disrupt the ionic do
`mains and permit the foaming process. On the other
`than, U.S. Pat. No. 3,322,734 teaches that the acid form
`of the ionic polymer should not be completely neu
`tralized-preferably the neutralization should be only
`80% complete and in no case should exceed 90% of the
`stoichiometric equivalence. Thus, it is emphasized in
`U.S. Pat. No. 3,322,734 that incomplete neutralization
`of the acid moiety is essential in order that the resulting
`products be fabricated.
`
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`65
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`Yita v. MacNeil IP, IPR2020-01139
`Page 2
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`

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`4,181,780
`3
`4.
`butyl rubber, halo-butyl or EPDM terpolymers. Addi
`The foams described in the present instant invention
`tionally, other unsaturated polymers contemplated are
`may be characterized as follows:
`partially hydrogenated isoprene, partially hydroge
`(a) the foamed products of the present invention are
`tough, strong and rubbery at use temperature behaving
`nated polybutadiene, or an isoprene-styrene random
`copolymer.
`in many ways like a chemically crosslinked elastomer;
`(b) at sufficiently high temperatures the foamed
`The expression "Butyl rubber' as employed in the
`specification and claims is intended to include copoly
`proudcts of the present invention which contain a non
`mers made from a polymerization reaction mixture
`volatile polar plasticizer can be made to have excellent
`melt rheological properties so these product, or used or
`having therein from 70 to 99.5% by weight of an isoole
`scrap material can be readily melt reprocessed, thereby
`fin which has about 4 to 7 carbon atoms, e.g. isobutyl
`ene and about 0.5 to 30% by weight of a conjugated
`enabling reuse and refoaning of waste material;
`(c) due to the unique ionic bonding in these systems
`multiolefin having from about 4 to 14 carbon atoms, e.g.
`isobutylene and about 0.5 to 30% by weight of a conju
`and the incorporation of a non-volatile high tempera
`ture polar flow improver, it has been found that in an
`gated multiolefin having from about 4 to 14 carbon
`atons, e.g. isoprene. The resulting copolymer contains
`appropriate elevated temperature range these foams
`have the characteristic of being reformable into differ
`85 to 99.8% by weight of combined isoolefin and 0.2 to
`ent shapes without substantially damaging the foam
`15% of combined multiolefin.
`Butyl rubber generally has a Staudinger molecular
`structure (see e.g., Example 7);
`(d) when reshaped at slightly elevated temperatures
`weight of about 20,000 to about 500,000, preferably
`and cooled, these flexible foams exhibit a novel memory
`about 25,000 to about 400,000 especially about 100,000
`20
`to about 400,000 and a Wijs Iodine No. of about 0.5 to
`effect;
`50, preferably 1 to 15. The preparation of Butyl rubber
`(e) the production of these foams from the hulk mate
`rial (containing a non-voltile polar plasticizer, foaming
`is described in U.S. Pat. No. 2,356,128 which is incorpo
`agents, flow improvers and compounding ingredients)
`rated herein by reference.
`exhibits several unusual and important characteristics
`For the purpose of this invention, the Butyl rubber
`25
`such as insensitivity of the foam production to tempera
`may have incorporated therein from about 92 to 10% of
`ture changes over a wide temperature region, very
`combined multiolefin; preferably about 0.5 to about 6%;
`rapid foam production because curing is not required,
`more preferably about 1 to about 4%, e.g. 2%.
`and excellent rheological melt properties;
`Illustrative of such a Butyl rubber is Exxon Butyl 218
`(f) these thermoplastic elastomer foams can be rap
`(Exxon Chemical Co.), having a viscosity average mo
`30
`idly produced by either high pressure compression
`lecular weight of about 450,000, a mole % unsaturation
`molding or extrusion foaming; and
`of about 1.5% and a Mooney viscosity of about 55 at
`(g) rubbery foams of good cell uniformity and small
`260 F. at 8 minutes.
`Halogenated butyl rubber is commercially available
`cell size can be produced at densities from below
`and may be prepared by halogenating Butyl rubber in a
`0.1 g/cc up to near bulk density.
`35
`solution containing between 1 to 60% by weight of
`SUMMARY OF THE INVENTION
`Butyl rubber in a substantially inert C5-C8 hydrocarbon
`The present invention relates to unique and novel
`solvent such as pentane, hexane, heptane, etc. and con
`tacting this Butyl rubber cement with a halogen gas for
`sulfonated elastomeric foam articles and processes for
`a period of about 25 minutes, whereby halogenated
`foaming these articles, wherein a sulfonated elastomeric
`polymer composition is modified with a non-volatile
`Butyl rubber and a hydrogen halide are formed, the
`polar plasticizer, foaming agents, and preferably other
`copolymer containing up to one halogen atom per dou
`ble bond in the copolymer. The preparation of haloge
`chemical additives, and is foamed to produce articles
`which exhibit a variety of unusual and desirable physi
`nated Butyl rubber is old in the art, see e.g. U.S. Pat.
`cal and rheological properties.
`No. 3,099,644 which is incorporated herein by refer
`45
`Accordingly, it is an object of our present invention
`ence. This invention is not intended to be limited in any
`to provide novel sulfonated elastomeric foam composi
`way by the manner in which Butyl rubber is haloge
`tions having superior quality and unusual characteris
`nated, and both chlorinated and brominated Butyl rub
`tics, wherein the compositions are formed from sulfo
`ber are suitable for use in this invention.
`nated elastomeric polymers, a non-volatile polar plasti
`Illustrative of halogenated Butyl rubbers is Exxon
`cizer and preferably selected chemical additives.
`Butyl HT-10-66 (a chlorinated Butyl rubber containing
`about 1.3 wt.% chlorine, having about 1.7 mole %
`GENERAL DESCRIPTION OF THE INVENTION
`unsaturation and a viscosity average molecular weight
`The present instant invention relates to improved
`of about 357,000).
`sulfonated elastomeric foamed articles and foaming
`Low molecular weight Butyl rubbers, i.e. Butyl rub
`55
`bers having a viscosity average molecular weight of
`processes for forming these articles wherein the sulfo
`nated elastomeric foams exhibit an unusual and useful
`about 5,000 to 85,000 and a mole % unsaturation of
`profile of physical characteristics, and wherein simple
`about 3 to about 4% may be sulfonated by the process of
`and unusually rapid processes are used to produce or
`this invention. Preferably, these polymers have a viscos
`modify the foams.
`ity average molecular weight of about 25,000 to about
`The elastomeric polymers of the present invention
`60,000.
`are derived from synthetic and natural polymers having
`The term "EPDM' is used in the sense of its definition
`olefinic unsaturation sites, wherein the polymer has
`as found in ASTM D-1418-64 and is intended to mean a
`terpolymer containing ethylene and propylene in the
`from about 0.1 to about 10.0 mole % olefinic unsatura
`tion. The unsaturation sites can be in the polymer back
`backbone and a diene in the side chain. Illustrative
`65
`bone, pendant therefrom or cyclic.
`methods for producing these terpolymers are found in
`In particulr, the unsaturated polymers of this present
`U.S. Pat. No. 3,280,082, British Pat. No. 1,030,289 and
`invention include low unsaturated polymers such as
`French Pat. No. 1,386,600, which are incorporated
`
`60
`
`50
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`Page 3
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`10
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`4,181,780
`5
`6
`herein by reference. The preferred terpolymers contain
`Sulfonation of the polymer is conducted at a tempera
`about 40 to about 80 wt.% ethylene and about 2 to
`ture between -10° C. and -- 100° C. Sulfonation oc
`curs, when the sulfonating agent is added to the poly
`about 10 wt.% of a diene monomer, the balance of the
`polymer being propylene. More preferable, the polymer
`mer solution. The sulfonating agent is preferably dis
`solved in a suitable solvent. Reaction time at room ten
`contains about 45 to about 75 wt.% diene monomer,
`perature may be about 5 min. to about 60 min., more
`e.g. 5.0 wt.%. The diene monomer is preferably a non
`conjugated diene. The Min of the terpolymer is prefera
`preferably about 30 min.
`bly about 10,000 to about 200,000; and more preferably
`The acid form of the sulfonated elastomeric can be
`quenched with a liquid aliphatic alcohol.
`about 15,000 to about 100,000; and most preferably
`The amount of desirable sulfonation depends on the
`about 20,000 to about 60,000. the Mooney viscosity of
`particular application. Preferably, the elastomeric poly
`the terpolyer at (1-8) minutes at 212 F. is preferably 5
`to 90, more preferably 10 to 60 and most preferably 15
`mer is sulfonated at about 10 to about 100 med.
`SO3H/100g of polymer, more preferably at about 15 to
`to 50 e.g. 40. The Mv of the EPDM is preferably below
`about 50 meq SO3H/100g of polymer, and most prefer
`about 350,000 and more preferably below about
`ably at about 20 to about 45 meq SO3H/100g of poly
`300,000; e.g. 270,000. The Mw of the EPDM is prefera
`mer. The mea of SO3H/100g of polymer was deter
`bly below about 500,000 and more preferably below
`mined by dissolving the acid form of the sulfonated
`about 350,000, e.g. 343,000.
`polymer in a mixed solvent of 95 parts of toluene and 5
`Illustrative of these non-conjugated diene monomers
`parts of methanol at a concentration level of 50 grams
`which may be used in the EPDM terpolymer are 1,4-
`per liter of solvent. The acid form is titrated with so
`20
`hexadiene, dicylcopentadiene, ethylidene norbornene,
`dium ethoxide to an Alizarin Thymolphthalein end
`methylene norbornene, propylidene norbornene and
`point. Sulfur analysis was done by Dietert Analysis.
`methyl tetrahydroindene.
`Polymers containing unsaturation and sulfonic acid
`A typical EPDM is Vistalon 2504 (Exxon Chemical
`groups have been found to be somewhat deficient in
`Co.) a terpolymer having a Mooney viscosity at (ML,
`thermostability. Therefore, it is desirable to neutralize
`25
`1-8, 212 F.) of about 40 and having 50 wt.% of ethyl
`the acid groups as part of the manufacturing of sulfo
`ene, 45 wt.% of propylene, and 5.0 wt.% of 5-ethyli
`nated elastomeric polymer. Neutralization further im
`dene-2-norbornene with an Mn of about 47,000, an Mv
`proves the physical properties of the sulfonated poly
`of about 145,000 and an Mw of about 174,000. The
`mer. Thus, the acid form of the polymer lacks adequate
`Vistalon 2504 can be reprocessed through an extruder
`physical properties and often the stability to be useful in
`30
`until a 20 Mooney value has been achieved.
`the applications envisioned for the foamed products.
`Another EPDM terpolyer, Vistalon 2504-20 is de
`In preparing the ionomer it is not necessary to neu
`rived from Vistalon 2504 (Exxon Chemical Co.) by a
`tralize every sulfonic acid group. Preferably, enough
`controlled extrusion process, wherein the resultant
`base is added to theoretically neutralize at least about 95
`Mooney viscosity at 212 F. is about 20. The Min of
`of the sulfonic acid groups; more preferably at least
`35
`Vistalon 2504-20 is about 26,000, the Mv is about 90,000
`about 98; and most preferably at least about 99.
`and the Mw is about 125,000.
`The neutralizing agents of the present invention are
`Vistalon 3708 (Exxon Chemical Co.) is a terpolymer,
`metallic salts of carboxylic acids, wherein the metallic
`having a Mooney viscosity (ML, 1 - 8, 260F.) of about
`ion of the metallic salt is selected from the group con
`45-55 and having about 65 wt.% of ethylene, about 3.3
`sisting of Groups IA, IIA, IB, IIB, A1 or Pb of the
`40
`wt.% of 5-ethylidene-2-norbornene; and about 31.7 wt.
`Periodic Table of Elements and mixtures thereof. (see
`% of propylene with an Mn of about 53,000, an Mw of
`page B-3, "Handbook of Chemistry and Physics",
`about 343,000 and an Mv of about 27,000.
`Chemical Rubber Publishing Co., 47th Ed.). Suitable
`Vistalon 6505 (Exxon Chemical Co.) is a terpolymer
`monovalent metal ions include NA, K, Li, Csh,
`having a Mooney viscosity (ML, 1--8, 260F.) of about
`Ag, Hg and Cut. Suitable divalent metal ions in
`45
`45-55 and having about 53 wt.% of ethylene, about 9.0
`clude Be+2,Mg+2, Ca+2, Srt-2, Bat-2, Cu+2, Cdt-2,
`wt.% of 5-ethylidene-2-norbornene and about 38 wt.%
`Hg+2, Sn+2, Fe+2, Pb +2, CO+2, Ni--2 and Znt-2. A
`of propylene.
`preferred cation is Zn-2.
`Nordel 1320 (DuPont) is another EPDM terpolymer
`Other neutralizing agents of this invention are metal
`havin a Mooney viscosity (ML, 1+8, 212 F) of about
`lic oxides, hydroxides, or C1 to C20 alkoxides, C1 to C20
`25 and having about 53 wt.% of ethylene, about 3.5 wt.
`alkanoates and mixtures thereof, wherein the metallic
`% of 1,4-hexadiene and about 43.5 wt.% of propylene.
`ion is selected from the group consisting essentially of
`In carrying out the present invention, an olefinically
`Groups IA. IIA, IB and IIB and mixtures thereof of the
`unsaturated polymer is sulfonated with a sulfonating
`Periodic Table of Elements. Illustrative examples are
`agent according to, for example, the method of either
`lead oxide, zinc oxide, calcium oxide, magnesium oxide,
`U.S. Pat. No. 3,642,728 and 3,836,511, both of which are
`ammonium hydroxide, sodium hydroxide, magnesium
`herein incorporated by reference.
`hydroxide, calcium hydroxide, or sodium ethoxide.
`It should be pointed out that neither the sulfonating
`Still other useful neutralizing agents are primary,
`agent nor the manner of sulfonation is critical, provided
`secondary and tertiary amines having up to 30 carbons.
`that the sulfonating method does not degrade the poly
`The foam compositions of the present invention are
`mer backbone.
`formed from a blend of the neutralized sulfonated elas
`In the practice of this invention, the polymer to be
`tomeric polymer, a non-volatile polar plasticizer which
`sulfonated can be dissolved in a suitable solvent and
`is used to control the viscoelasticity of the elastomeric
`reacted with the sulfonating agent. The solvent medium
`ionomer at processing temperatures, a foaming agent,
`should be a neutral one for the rubber and the sulfonat
`and preferably oils and fillers. Selected crystalline poly
`65
`ing agent. The solvent is preferably an aromatic hydro
`mers and lubricants may also be added in minor
`carbon, an aliphatic hydrocarbon, or a halogenated
`amounts. Other additives such as coloring agents and
`aromatic hydrocarbon.
`stabilizers which are known in the art can also be added,
`
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`7
`or to refabricate used or discarded foam requires the
`if desired. The cell structure of the resultant foams
`presence of the nonvolatile plasticizers. At the elevated
`depends in a complex way on a number of interdepen
`temperature at which foaming takes place (and also any
`dent variables including the choice of non-volatile polar
`thermal reshaping operations or reprocessing) the non
`plasticizer, the amount of non-volatile polar plasticizer,
`volatile polar plasticizer must be very effective in re
`the foaming agent, the sulfonated gun, and the various
`ducing the melt viscosity of the sulfonated elastomer to
`additives and their concentrations. In addition, the de
`enable rapid and satisfactory foaming.
`tails of the particular foaming process can have a signifi
`The foaming agents used in combination with the
`cant effect on cell structure, for example, whether ex
`preferential polar plasticizer include chemical com
`trusion, compression molding or some other foaming
`pounds that decompose at or below the temperature of
`procedure is used, and the temperatures, heating times,
`foaming to liberate gases, and low boiling liquids which
`or foaming rates employed. Some specific examples of
`are converted into gaseous form by heating. The chemi
`some materials, techniques, and conditions which pro
`cal foaming agents have been found to be particularly
`duce satisfactory foams are given later in this applica
`easy to use and generally give excellent results.
`tion.
`The blowing (foaming) agent may be a chemical
`A preferential polar plasticizer is used to help weaken
`blowing agent or a physical blowing agent or a combi
`the ionic associations of the neutralized sulfonate
`groups prior to, and during the foaming operation. This
`nation of chemical and physical blowing agents. In the
`case of physical blowing agents a nucleating agent may
`is necessitated by the fact that for most neutralized
`be helpful for obtaining good cell structure. Chemical
`sulfonated elastomeric polymers, quite high tempera
`blowing agents are particularly effective as nucleating
`tures are required to obtain appreciable flow rates; and,
`20
`agents for physical blowing agents. If a physical blow
`for some, this temperature is above the thermal decom
`position temperature of the polymer. The preferential
`ing agent is used, the ionic elastomeric material must
`not be soluble in the physical blowing agent nor should
`polar plasticizer, through the weakening of the ionic
`the backbone polymer chain (in the absence of the ionic
`associations decreases, the melt viscosity of the neutral
`group) be soluble in the physical blowing agent. In the
`ized sulfonated elastomeric polymer at elevated temper
`25
`atures thereby making it readily processable.
`foaming process the polymer is heated under pressure
`By the proper selection of the preferential polar plas
`and the foam structure is nucleated by rapid decrease in
`the pressure. Heating the polymer, without utilizing a
`ticizer, it is possible to obtain excellent physical proper
`rapid decrease in pressure was not found to be very
`ties for the plasticized, neutralized sulfonated elasto
`meric polymer. A preferred class of preferential plasti
`effective in producing foma of relatively uniform cell
`structure. The foaming of the elastomeric ionomer ma
`cizers are metallic salts of fatty acids wherein the fatty
`terial differs from the foaming of thermoplastic ionomer
`acid has about C12 to about C40 carbon atoms, more
`materials such as lightly sulfonated polystyrene in that
`preferably about C14 to about C26, most preferably
`heating at atmospheric pressure is able to produce good
`about C16 to about C22 carbon atons and the metallic
`quality foams of sulfonated polystyrene. Also, it is
`action is selected from the group consisting of zinc,
`known that many sulfonated polystyrene foams using
`antimony, lead or Groups IA, IIA, IB or IIB of the
`physical blowing agents did not require nucleating
`Periodic Table of Elements and mixtures thereof. Be
`cause with metal salts the cation might partially ex
`agents.
`The foaming agents used in the process of the instant
`change with the cation of the neutralized sulfonated
`polymer, it is preferable (but not necessary) that the
`invention are well known in the art and include com
`pounds which when incorporated in the polymer com
`metal salt contain the same cation as the sulfonated
`position decompose at or below the temperature of
`polymer. A preferred plasticizer is zinc stearate, prefer
`foaming to liberate gases, and the low boiling liquids
`ably in combination with a zinc neutralized sulfonated
`polymer. A less preferred class of preferential plasti
`which are converted into gaseous form by heating.
`Examples of foaming agents which decompose at
`cizer is the aforementioned fatty acids alone or in com
`45
`specific temperatures to liberate gases include the fol
`bination with the aforementioned metallic salts of the
`lowing representative compounds for which the ap
`fatty acids. Other preferential plasticizers which are
`proximate temperature range of decomposition for the
`preferred in the instant compositions include amides,
`neat material is indicated in parenthesis: sodium bicar
`ureas, amines or thioureas and mixtures thereof. The
`preferential plasticizers are incorporated into the com
`bonate (160-200 C.), sodium bicarbonate and citric
`50
`positions at about 0 to about 60 parts by weight per
`acid combination (O.C. to 200 C.), azobis formamide
`combination (160-200 C.), azobisisobutyronitrile
`hundred parts of the metal neutralized sulfonated elasto
`meric polymer, more preferably at about 2 to about 40,
`(90-115° C), diazominobenzene (90-110° C.),
`N,N'dimethyl-N,N'-dinitroisoterephthalamide
`and most preferably about 8 to about 30.
`(90-105 C.), N,N'-dinitrosopentamethylenetetramie
`Polar plasticizers can be distinguished into two
`55
`(130-190° C), toluene-4-sulfonyl hydrazide (100-100
`categories-volatile and non-volatile plasticizers. The
`C.), 4,4'-oxybis (benzene sulfonyl hyrazide) (120-140
`major practical difference between the two types is that
`C.), and similar compounds known in the art. (For ex
`the non-volatile plasticizers remain with the final prod
`ample, see reference "Plastic Foams'; Vo. II, by C. J.
`uct while the volatile plasticizers are volatilized from
`the ionomer during or shortly after a processing opera
`Bennings, Wiley Interscience Publishers, 1969, Appen
`60
`dix A-II.
`O.
`When chemical foaming agents are employed, gener
`The foams of this invention require the use of a non
`volatile polar plasticizer to achieve several of their
`ally from about 0.25 to about 5 parts per hundred by
`weight (based on 100 parts of the neutralized sulfonated
`desirable and unusual properties. For example, the ther
`elastomeric polymer) of the foaming agent will be used;
`mal reshaping process described earlier and also de
`65
`tailed in an example requires the presence of the non
`more preferably about 0.5 to about 4.
`volatile plasticizer; and the economically important
`If a low boiling liquid is used as a foaming agent,
`characteristic of being able to melt reprocess scrap foam
`suitable liquids include butane, pentane, hexane, and
`
`35
`
`30
`
`MacNeil Exhibit 2060
`Yita v. MacNeil IP, IPR2020-01139
`Page 5
`
`

`

`10
`
`15
`
`Oil Code #
`Type Oil
`Sunpar 115
`Paraffinic
`Sunpar 180
`Paraffinic
`Sunpar 2280
`Paraffinic
`Flexon 340
`Aromatic
`Naphthenic Flexon 765
`
`4,181,780
`10
`9
`about 750. The preferred process oils are paraffinics.
`heptane. Similarly, materials which are gases at room
`Typical oils are summarized in Table II.
`temperature may be injected into the material to be
`The oils are incorporated into the blend composition
`foamed under pressure. Such gases include carbon diox
`at a concentration level of about 0 to about 150 parts per
`ide, dichlorodifluoromethane, nitrogen and the like.
`hundred based on 100 parts of the sulfonated polymer.
`In the preparation of the foam composition, a nucleat
`More preferably at about 5 to about 125 and most pref
`ing agent can also be added to the compositions, if it is
`erably at about 10 to about 100.
`needed, to produce a foam having small and uniform
`cells. Typical nucleating agents are citric acid and so
`TABLE II
`dium bicarbonate as well as a metallic oxide such as
`%
`%
`Visco-
`magnesium oxide.
`% Aro- Satu
`sity
`Various additives can be compounded with the plasti
`M. Polars
`matic
`rates
`SS
`cized neutralized sulfonated elastomeric polymers,
`400
`0.3
`12.7
`87.0
`155
`wherein the physical and rheological properties are
`570
`0.7
`17.0
`82.3
`750
`modified due to the incorporation of these additives.
`720
`1.5
`22.0
`76.5
`2907
`m
`1.3
`70.3
`28.4
`20
`The additives include fillers, pigments, lubricants and
`505 - 0.9
`20.8
`78.3
`polyolefinic thermoplastics, process oils and mixtures
`thereof. These additiv