CA1335134C - Polyamide composition resistant to fluorocarbon and hydrocarbon permeation - Google Patents

Abstract

The present invention is a polyamide composition which is resistant to fluorocarbon and hydrocarbon permeation and at the same time has controllable flexibility. The composition of the present invention comprises from about 50 to 90 percent by weight of a polyamide, from about 5 to 40 percent by weight of a rubber phase that may be melt-processed at from about 425 to 625°F (218 to 329°C) without significant degradation, and from about 5 to 40 percent of a polar polyethylene.
The composition can also have from about 0 to 15% by weight of a plasticizer and from about 0 to 10% by weight of a polyamide chain extender.

Description

POLYAMIDE COMPOSrTION RESISTANT TO
FLUOROCARBON AND HYDROCARBON PE~MEATION
BACKGROUND OF THE INVENTION
This in~ention relates to polyamide compositions; and more particularly, to polyamide compositions which are resistant to fluorocarbon and hydrocarbon permeation.
At the present time, it is known to use nitrile rubber-based compositions to ma~e fluorocarbon permeation resistant articles, such as hosinq and tubing. Nitrile rubbers are butadiene acrylonitrile copolymers. They are flexible and known for gas permeation resistance and oil resistance. Babbit, The Vanderbilt Rubber Handbook, RT Vanderbilt (1978) discloses a typical nitrile rubber composition, useful to ma~e hosing (at page 720). While such compositions may be useful to blend with polyamides and form fluorocarbon permeation resistant artic1es, the processing of such compositions presents certain limitations. A critical concern is that at the temperatures necessary to process polyamides, nitrile rubbers might decompose to form hydrogen cyanide and acryloni~rile monomer. Both of thefie materials are undesirable. Therefore there is a need in the art for a polyamide composition which i8 résistant to hydrocarbon and fluorocarbon permeation, which is controllable with respect to flexibility, and which can be processed at processing conditions typically used to process nylon, i.e., 425 to 625F (218 to 329~C), without emitting undesirable degradation compounds.

~' -2- ~ ~3 SUMMARY OF THE INVENTION
The present invention is a polyamide composition which is resistant to fluorocarbon and hydrocarbon permeation and at the same time has controllable flexibility. The polyamide composition of the invention contains a rubber phase to flexibilize, which is not in and of itself resistant to the permeation of fluorocarbons and hydrocarbons, but can be processed at the high processing temperatures of polyamides wh~ch are typically between about 425 to 625oF(218 to 329C). It h~s been discovered that selective polyethylenes functionalized with polar groups can be incorporated with this rubber phase to result in a fluorocarbon and hydrocarbon permeation resistant composition that also retains tensile-type physical properties while maintaining a lower flex modulus. Thus, the composition of the present invention comprises from about 50 to 90 percent by weight of a polyamide, from about 5 to 40 percent by weight of a rubber phase ~hat m~y be melt-processed at from about 425 to 625~- (218 to 329C) without significant degradation, and from about 5 to 40 percent of a polar polyethylene. The composition as indicated above can also have from about O to 15% by weight of a plasticizer and from about O to 10% by weight of a polyamide chain extender. These last two ingredients can be used to further flexibilize the polyamide or balance and fine-tune flexibility and physical properties, without deterring from fluorocarbon and hydrocarbon resistance.
The present invention also includes fluorocarbon and hydrocarbon permeation resistant articles made from the above-recited composition. Articles of particular interest are tube and hosing used as conduits for fluorocarbons commonly used as refrigerants for refrigerators and air conditioning systems.

1 3 3 ~

_3-DESCRIPTION OF THE PREFERREDI~h~ TS
The present invention is a polyamide composition which comprises polyamide, a rubber phase, a polyethylene functionalized with polar groups and optionally a plasticizer and polyamide chain extender.
The polyamide component of the composition of the in~ention is the predominant component. ~referred percent ranges by weight of this component are from about 50 to 90~, preferably about 60 to 90% and more preferably about 70 to 80% by weight of the total composition. Polyamides suitable foc use herein include the long chain polymeric amides havinq recurring amide groups as part of the polymer backbone and preferably having a number a~erage molecular weight, as measured by end group titration of about 15,000 to 40,000. The polyamides suitable for use herein can be produced by any con~entional process known in the art.
Non-limiting examples of such polyamides are:
(a) those prepared by the polymerization of lac~ams, preferably epsilon-caprolactam (nylon 6): (b) those prepared by the condensation of a diamine with a dibasic acid, preferably the condensation of hexamethylene diamine with adipic acid (nylon 6,6), the condensation of hexamethylene diamine with sebacic acid (nylon 6,10) and polytetramethylene adipamide (nylon 4,6); and (c) those prepared by self-condensation of amino acids, ereferably self-condensation of ll-aminodecanoic acid (nylon-Ll);
or random, block, or graft interpolymers consisting of two or more of these polyamides. Preferred are those obtained by the polymerization of epsilon-caprolactam. The most preferred are copolymers of caprolactam and hexamethylene adipamide (N6 66) ~ ~ _4_ ~ 335 1 34 Polyamides such as nylon-6 or nylon 6,6 can contain a ~ariety of terminal functionalities, including: (a) a carboxyl group attached to both ends of the polyamide chain; (b) a carboxyl group attached to one end and an amide group attached to the other end of the polyamide chain (the ~capped~
end) (only polycaprolactams): (cj an amino group attached to both ends of the polyamide chain; and (d) a carboxyl group attached to one end and one amine group attached to the other end of the polyamide chain (polycaprolactams.) The polycaprolactam if unwashed can contain up to 15~, and typically from O.S to 12S by weight based on the weiqht of polycaprolactam, of a caprolactam monomer or wa~er extractable caprolactam oligomers.
In a N6 66 composition, the caprolactam amount corresponds to the amount of caprolactam in the N6 66 polymer.
The composition contains a rubber phase which can be eolar or nonpolar, and is capable of ~ei~g melt processed at from about 425 to 625E~ (218 to 329 C~, without significant degradation. It is preferred that non-nitrile type rubbers be used. As used herein, a polar rubber phase means a low modulus ~lexible polymer with a glass transition below OoC, preferably below -25C and containing polar monomers o~ acids, esters, ethers, aldehydes, ketones, alcohols and halides. The polar rubber may also contain an anhydride for reaction with the nylon.
In some cases the rubber phase may be considered to be nonpolar. By this is meant a low modulus flexible polymer with a glass transition below OC, and preferably below -25C, and containing non-polar monomers such as ethylene and aapha-olefins such as propylene, butylene and the li~e. The non-polar rubber may also contain an anhydride group for reaction with the nylon. It should be _ 1 335 1 3~

appreciated, however, that when the rubber phase is nonpolar, the third com~onent of the compositions o~
the in~ention (as described in detail below) should be adjusted accordingly, to attain the desired fluorocarbon or hydrocarbon cesistance. Preferred in the context of nonpolar rubbers are copolymers of ethyLene and other than ethylene monomers, suc~
as alpha-olefins, having a reacti~e moiety gra ~ ed to the ethylene copolymer. The ethylene and alpha-olefin is preferably a copolymer of ethylene aQd an 1~ alpha-olefin selected from at least one C3-C8, and preferably C3-C6 a:lpha-olefin Propylene is a preferred monomer selected as t ~ C3-C~ alpha-ole~in in the copolymer. Other C3-C6 ~lpha-olefins,. such as l-butene, l-pentene, and l-hexene can be used in lS place o~ or in addition to propylene in the copolymers. Ethylene/propylene diene polymers are also prefe~red ~or U8Q herein.
In other prQferred embodiments, either polar or nonpolar rubbers may be ~unctionalized. For example, a carboxyl or carboxylate functionality can be supplied by reacting the ethylene/c3-c6 alpha-olefin copolymer with an un~aturated reactive graft moiety takQn from the class consi~ting of alpha,beta-~thylenically unsaturated dicarboxylic acids ha~ing rom 4 to 8 carbon atoms, or deri~atives thereof.Such derivatives include anhydrides of the dicarboxylic acids. Illustrative of such acids and derivati~es are mal~ic acid, maleic anhydride, maleic ac~d ~Qnoethyl ester, metal salts of maleic acid monoethyl ester, fumaric acid, fumaric acid monoethyl ester, itaconic acid, vinyl benzoic acid, ~inyl phthalic acid, metal salts of fumaric acid monoethyl ester, monoestQrs of maleic or fumaric acid or itaconic acids where the alcohol is methyl, propyl, isopropyl, butyl, isobutyl, hexyl, cyclohexyl, octyl, 2-ethyl hexyl, decyl. stearyl. methoxy ethyl, ethoxy ~ 335 t 34 ethyl, hydroxy or ethyl, and the like. The reactive moiety can be grafted to the ethylene copolymer by any well-known gra~ting process.
A useful reactive copolymer of ethylene and alpha-olefin contains from 30 tQ ~0 and preferably 40 to 45 weight percent of the alpha-olefin based on the ethylene. The copolymer also contains from 0.1 to 9S, and preferably 0.1 to 4 percent, and more ereferably 0.3 to 2.0 percent by weiqht of the grafting moiety. The graft copolymer has a number average molecular weight of from 2,000 to 100,000, preferably 2,000 to 65,000, more preferably 5,000 to 35,000, and most preferably 5,000 to 20,000. Typical values of reduced solution viscosity (RSV) are from 0.5 to 3.5. A R5V of 2.8 corresponds to a number average molecular weight of about ~0,000, an RSV of 2.0 corresponds to 35,000, and RSV of 1.0 corresponds to a number averaqe molecular weight of 12,000, RSV
is measured on a 0,lS solution in xylene at llo~C.
A good guideline to the selection of a rubbery phase component can be made by referring to that rubberls solubility parameter. A very soluble material will have a rela~i~ely high solubility ~arameter, and could be considered polar in nature.
The reverse would be true for a relatively nonpolar material. The solubility parameter in its use in permeation resistance i8 reviewed in U.S. Patent No.
4,261,473. The solubility parameter, as used in that patent and for use in the present invention, i5 defined as the square root of the coheçion energy density (calories per cubic centimeter, CAL/cc) and is reviewed in Brandrup et al., Polymer Handbook, Chapter 4, published by John Wiley & Sons, Inc.
(1967). The solubility parameter of typical fluorocarbons i8 about 5.5. The solubility parameter of various materials is summarized in the following Table l for ease of reference:

TABLE. 1 Solubility ~arameter (caltcc) 5 fluorocarbon 5.5 polyethylene 8.0 polypropylene 7.9 EPR' Nitrile Rubbee (B~AN) 80/20 8.7 70t30 9.4 60/40 10.5 0/100 12.8 15 polyvinyl acetate 9.4 polyvinyl alcohol 12.6 polylauryllactam (N12) 9-5 polyundercanamide (N11) 9.9 polycaprolactam (N6) 12.7 polyhexanethylene-sebacamidetN6 10) 12.5 polyhexamethylene adipamide(N6 6) 13.6 caprolactam/hexamethylene diammonium 12.8 adipate copol~r}ner N6, 66 n-ethyl o,p-toluenesulfonamide 11.9 Thus, one of skill in the art will appreciate that if a nonpolar rubbec is chosen as the rubbery phase component, it i8 preferred to use about 0 to 40%, and preferably from 10 to 30% and more preferably about 5 to 20% of a nonpolar rubber having a solubility parameter of less than about 9. Such rubbers have been found to further flexibilize the polyamide composition without substantially affecting tensile properties of the polymer. As indicated above, these nonpolar polymers can include polymers and copolymers having the same monomeric units as the polar polymers described above so long as tne total solubility parameter of the polymer is less than about 9Ø While these nonpolar rubbers need not contain groups tnat react with the end groups of the polyamide, it is preferred that they contain a small amount of reactive groups so as to form a network graft structure wherein the end groups of the polyamide are bonded to the reactive groups on the nonpolar rubber. The present inventors do not wish to be bound by theory; however, it is believed that this network structure is one of the reasons that the use of such materials helps to maintain physical properties while pro~iding a lower flexural modulus.
Particularly preferred for purposes of the rubbery phase of the compositions of the present invention are ethylene polymers such as ethylene ethyl acrylates, ethylene vinyl acetates and ethylene vinyl alcohols, and ethylene copolymers, such as ethylene/propylene copolymers, ethylene/propylene/diene copolymers, ethylene/butylene copolymers: and the like.
The present inventors have also discovered that the addition of a functionalized polyethylene can be incorporated into the composition of the present invention to impart hydrocarbon resistance without detracting from the mecnanical properties of the composition as a whole. Thus, the present composition also includes from about 5 to 40%, and preferably from about lO to 35~ of a polyethylene ha~ing functional groups. ~aid polyethylene preferably ha~ a solubility parameter equal to or greater than about 9.O, and said polyethylene is capabl* o being melt- processed at from about g25 to 625F (218 to 329C) without signlficant degradation. The polyethylene of the present invention is preferably an ethylene-based copolymer ha~ing sufficient polar groups along the backbone or grafted or otherwise attached thereto so that tne solubility parameter of the total copolymer is preferably greater than about 9Ø The polar moiety may or may not be reactive with the end groups such as acid or amine groups of the polyamide.
Preferred polyethylenes for purposes of the present invention are those composed of ethylene monomeric units and polar monomeric units, such as anhydrides, acid groups and salts thereof, ester groups, aldehydes, ketones, ethers, hydroxyl groups, halogen groups, salts, and the like. ~articularly preferred are salts of metals, such as salts of zinc, sodium, potassium, calcium, copper, lead and the like; esters, alcohol, acids, and the like. A good description of ionomers may be found in U.S. ratent No. 4,404,325. Ionomers having relatively low molecular weight, for example, a molecular weight of about 1500-3500, may also be useful.
The composition may also contain a plasticizer that is suitable for plasticizing the polyamide component of the composition. The flexibility of the overall composition of the invention can be improved to an even greater extent with the addition of such a plasticizer. Preferred amounts range from about 2 to 20~ by weight of a plasticizer, particularly preferred being about s% to about ?os . Such plasticizers may vary widely and include but are not limited to lactams such as caprolactams and lauryl lactam, sulfonamides such as o,p-toluene sulfonamide, n-ethyl o,p-toluene sulfonamide, n-ethyl o.p-toluene sulfonamide, and n-butyl benzenesulfonamide. Other plasticizers include those selected from the group consisting of phthalate plasticizers, adipate plasticizers, phosphate plasticizers, glycolate plasticizers as well as the indicated sulfonamide plasticizers, trimellitate plasticizers and polymeric-type permanent plasticizers.

~ 1 335 1 3~
- 1 o Optionally, it has been found that i~ lar~e amounts of a plastici~er are used to attain greater flexibility in the overall comeosition, it may also be desirable to add a fifth component, a polyamide chain extender to attain a higher molecular weight species with a melt index suitable for extrusion type products. A higher molecular weight species will also retain greater levels of plasticizer without exuding them from the composition.
By polyamide chain extender i8 meant a l compound which can react with both the amine and acid to form amide links to increase molecular weight.
For example, U.S. ~atents Nos. 4,433,116, 4,417,031 and 4,417,032 describe suitable chain extenders.
Suitable amounts range from about O to 10% by weight, pre~erably O to 5% and most preferably about 0.1 to about 3%.
The composition can contain other polar materials such as polyvinylacetates, inorganic salts.
and the like to increase resistance to fluorocarbon or hydrocarbon premeation.
The compositions of the invention may also contain one or more conventional additives which do not materially affect the impact properties of the composition, such as stabilizers and inhibitors of oxidative, thermal, and ultraviolet light degradation, lubricants and mold release agents, colorants, including dyes and pigments, flame-retardants, fibrous and particulate fillers and reinforcementc, nucleators, and the like. These additives are commonly added during the mixing step.
Representative oxidative and thermal stabilizers which may be present in blends of the present invention include Group I metal halides, e.g., sodium, potassium, lithium; cuprous halides, e.g., chloride, bromide, iodide: hindered phenols, hydroquinones, aromatic ~ne i, ~nd varieties of 3 5 1 3 ~
substituted members of those groups and combinations thereof.
Representative ultraviolet light stabilizers, include various substituted resorcinols. salicylates, benzotriazoles, benzophenones, and the like.
Representati~e lubricants and mold release agents include stearic acid, stearyl alcohol, and stearamides. Representative organic dyes include nigrosine, while representative pigments, include titanium dioxide, cadmium sulfide, cadmium selenide, phthalocyanines, ultramarine blue, carbon black, and the like.
Representative flame-retardants include organic halogenated compounds such a~
decabromodiphenyl ether and the like.
The compositions of this invention can be prepared by melt blending a polyamide and at least one polymer into a uniform mixture in a single or twin screw extruder or otner melt-compounding equipment.
The compositions can be made into a wide range of useful articles by conventional molding methods employed in the fabrication o~ thermoplastic articles, i.e., as molded parts, extruded shapes, e.q., tubing, films, sheets, fiber~, sheets, fibers and oriented fibers, laminates and wire coating.
"Moldingl' means forming an article by deforming the blend in the heated plastic state.
The composition of the present in~ention i8 particularly u6eful for extruded articles including tube and hosing to transport fluorocarbon fluids.
The compositions are useful in making a variety of these types of tubing and hose as well a~ extruded tube and hose, pipe made of nylon, coextrusions of nylon with other polymeric materials, and coatings.

i~35 1 3~

EXAMPLES
Several examples are set forth below tO .
illustrate the nature of the in~en~ion and the mannec of carrying ie out. However, the inven~ion should not be considered a~ being limited to the details thereof. All parts are percents by weight unless otherwise indicated. Raw materials employed are as follows:
Raw Materials EmDloYed XPN - L576 Nylon 6t66 (85~15) also referred to as ~-Caproamide/
hexamethylene diamine adipate (85/LS) containing a~proximate 7 to 8S caprolactam.
MP Nylon 6 containing 9 to llS
caprolactam unextracced.
EPM-g-MA Ethylene propylene rubber with 0.45S maleic anhydride grafted to it. The ethylene content i~
45%.
E/EA/MA Ethylene/ethyl acrylate (66/33) copolymer containing 1% maleic anhydride.
EAA Ethylene/acrylic acid copolymer (93.5~6.5 from Dow Chemical Co.) 5-9721 A zinc ionom~ from Duront, namely Surly~ g721 chemically named ethylehe/methacrylic acid/zinc metnacrylate (90/4/6) terpolymer.
OPTSA ortho, para-toluene sulfonamide. a nylon plasticizer.
30 U.C.BK Uni~ersal carbon black dispersion as 40% blac~ on 60%
e~hylene vinyl acetate carrier.
EVOH An ethylene ~inyl alcohol copolymer, specially ethylene/~inyl alcohol/~inyl acetate (80/19/1) terpolymer.

*Trade Mark _ _ _ _ ~ -13- 1 3 3 5 ~ 3 4 The compositions in the followinq Examples were generally prepared by f irst dry blending the materials, melt-extruding at about 500F (260CC) on a 1"
(2.54cm) single screw, extruder, using a conventional screw with an L/D of 25:1 and equipped with a Uaddock mixing head, Extrudate strands were rapidly passed through a water bath. The strands were passed through a pelletizing machine, and the pellets were collected. Test specimens were molded at a temperature slightly above the polyamide melting point.
The mold temperature was maintained at about 160-180F
(71-82C). The lding cycle was 10 to 30 seconds forward ram, and 10 to 25 seconds on hold.

The melt index was determined according to ASTM D-1238 Condition Q. The impact values were ~ested according to ASTM D=256 notched Izod using 1/8"
(.32cm) or 1/4" (.64cmJ te~t specimens as indicated. The tensile and elongation were tested according to ASTM
D-638, and the flexural modulus was tested according to ASTM D-790 In the Examples, the following ma~erials were used. The polyamide was nylon 6/66 copolymer which is a copolymer containing 92 mole percent of caprolactam and 8 mole percent of hëxamethylene adipamide. This copolymer was unwashed and contained from 7 to 9 percent of caprolactam monomer. The copolymer had a formic acid viscosity of 70. The formic acid viscosity is measured using 5.5 grams of nylon dissolved in 50 ml. of formic acid, 90S
3 concentrated.
Fluorocarbon permeation testing was performed according to the Springborn Testinq Institute procedure. In general, the test procedure entailed obtaining tare weight of equipment assembly (this included a cell, pressure cap, test specimen, screen); clamping the test specimen, cooling assembly -14- ~ 335 1 34 to below 0CC, charging 60 grams of dichlorodi-fluorometnane (Re~rigerant 12), sealing tne charged cell with pressure cap, conditioning for 2 nours in a 100C o~en, cooling to ambient and obtaininq initial weight (to 0.01 gram). The specimens were then S exposed ~or 3 days at 100C, cooled, weighed. Weight checks were repeated. Weight losses were reported between successive data times.
EXAM~LES 1-6 Example 1-6 illustrate compositions of the present in~ention ba~ed on nylon 6/66 copolymers described above. These examples illustrate various combinations of a rubber phase, a polar ethylene copolymer and a plasticizer. The rubber phase consisted of an et~ylene propylene copolymer ha~ing a maleic anhydride grafted thereto. The ethylene propylene maleic anhydride gra~t (EPMA) contained 45S
ethylene, SSS propylene, and 0.45S maleic anhydride ~ra~ted thereto. It had a reduced solueion viscosity of L.6. The reduced solution viscosity was measured in a 1~ solution in xylene at 110C.
The polar polyethylene was Surlyn 9721 ionomer sold by Du~ont. This material is indicated to be an ~thylene methacrylic acid copolymer containing about lOS methacrylic acid which is 60S
neutralized with zinc. This material has a melt index of 1Ø The plasticizer was Santicizer 9 which is o,p-toluene sulfonamide previously sold by Monsanto Corporation and described in their bulletin entitled ~IPla~ticizers and Resin Modifiers"-IC/PL-361.

Example 1 illustrates a composition of the present invention. It is based on a nylon 6,66 copolymer having 85 mole percent of caprolactam and N-ethyl o,p-toluene sulfonamide. and lS mole percent o~ hexamethylene adipamide. The copolymer is unwashea and contains ~rom 7 to 9 percent of *Trade Mark 1 3351 3~

caprolactam monomer. The composition further contains an ethylene propylene copolymer having maleic anhydride grafted thereto (hereina~ter ErMA).
The EPMA contains a 45 to 55 wt. percent ratio of ethylene to propylene. There is 0.66~ by weight maleic anhydride grafted to tne ethylene ~ropylene copolymer. This copolymer has a reduced solution YisCosity of 1.5 weight estimated as 10,000 to 12,000. The reduced solution viscosity is measured using a 0.1 percent solution in xylene at 110C. The E~MA is the nonpolar rubber having insufficient maleic anhydride to have a solubility parameter of greater than 9Ø The solubility parameter of the EPMA is estimated to be approximately 8Ø The composition additionally contains an ethylene acrylic acid copolymer. The ethylene acrylic acid copolymer (hereinafter EAA) was commercially available from Dow Chemical as Dow EAA
resin 455. It is described as having a melt index of 5.5 grams per 10 minutes and an acrylic acid content of 6.5 percent and an ethylene content of 93.5S with percents by weight.
The physical properties of the composition are summarized in Table 1 below:

Comp L comP 2 Comp 3 Ex 1 xrN-l576 70 60 50 60 EPM-g-MA 30 40 50 30 1!'SFR Ni 1 Ni 1 Ni 1 Ni 1 Fl.Mod.
psi 67K 40-45K 14K 49K
(MPa) (462) (27~-310) (97) (338) 0 YIELD ST . PSI 3450 2875 1570 2900 (MPa) (24) (20) (11) (20) YIELD EL . % 40 45 40 40 U.T.ST., PSI 6050 5280 2360 5650 (MPa) (42) (36) (16) (39) U.EL. % 285 290 115 290 The melt flow ratio was measured according tO
ASTM test number D-1238. All compositions had nil melt flow under this test. A review of the Comparative I and r I and Example 1 shows that the substitution of 10% of the eolar EAA rubber resulted in the maintenance of physical properties when compared to Comparative II. The flexural modulus was somewhat higher than when using a corresponding equivalent amount of nonpolar rubber. However, when considering Comparative I, the flexural modulus was still significantly lower. The composition of Example 3, with 50~ level of nylon and reactive rubber respectively, shows that excessive rubber to flexible can deteriorate physical properties.

Examples 2-5 illustrate compositions containinq varying amounts of the nylon 6/66, EPMA
and EAA, of the type used in Example 1. The compositions and physical property results are summarized in Table 3 below :

-Ex 2 Ex 3 Ex 4 Ex 5 EPM-g-MA 35 25 20 10 FL.MOD.

(MPa) (290) (345) (379) (483) FL. STR., PSI 2000 1940 2000 2400 (MPa) (14) (13) (14) (17) YIELD ST. PSI 2340 2200 2560 2960 (MPa) (16) (15) (18) (20) YIELD EL., % 30 30 30 30 U.T.ST., PSI 3500 3730 3960 3500 (MPa) (24) (26) (27) (24) U.E.. , ~ 150 250 270 150 A re~iew of Table 3 indicates that the amounts of polar polyethylene and rubber phase can be widely varied while maintaining satisfactory ten~ile lS properties and demonstrating relati~ely low flexural modulus. Reference is made to the comparati~es in Table 2 which indicate that when only the rubber is used at a SOS level, flexural modulus is reduced substantially. Howe~er, physical properties also deteriorate. A re~iew o~ Examples 2 through ~ show that a 50~ level of the combination of polar polyethylene and rubber phase. the flexural modulus is still relatively low, although not as low as when using only the nonpolar rubber, and still enjoys the benefits achie~ed with varying amounts of the polar polyethylene. More importantly, a re~iew of the physical properties of each of the Examples 2 through S indicate a higher tensile strength then when only the rubber phase is used. Therefore, the combination of a polar polyethylene and rubber phase enables the flexural modulus to be decreased while maintaining a higher tensile strength then is possible when no polar polyethylene is used, and at the same time ha~ing a lower flexural modulus similar to that achie~ed when only the polar polyethylene is used.

1 33~ ~ 34 Ex 6 EX 7 EX 8 EX 9 EPM-g-MA 15 10 10 10 S 9721 15 20 ~5 15 YIELD ST. ~rsI 3370 3240 26~0 ,570 (MPa) (23) (22) (18) (1~) YIELD EL., ~ 30 30 30 35 U.T.ST., PSI 7720 7980 6860 7620 (MPa) (53) (55) (47) (53) 10 U.EL., ~ 300 300 290 335 FL.MOD.

(MPa) (317) (297) (248) (228) 15 XPN-ls76 58 58 EPM-g-~L~ 16 10 YIELD ST.,PSI 2Q45 2620 (MPa) (20) (18) YIELD EL., % 30 30 U.T.ST., PSI 8200 7800 (MPa) (57) (54) U.EI.. , % 330 320 FL.MOD. 31K 27K
PS I (MPa ) (214) (186) Table 3 shows tnat flexible fluorocarbon and hydrocarbon resistant compositions can be produced by incorporating an ionomer or an ionic copolymer (S9721). This salt-containing copolymer can be expected to product a very hi~n level of permeation resistance. What is also shown, is that flexibility can be maintained by the inclusion of the OPTSA
(o,p-toluene sulfonamide) plasticizer.

Examples 12 - 17 include embodiments of the present in~ention containing only a polar rubber, with and without a nylon plasticizer. Tne polymer ~ 33~ ~ 3~

used is a terpolymer o~ ethylene, ethylacrylate and maleic anhydride in a mole ratio of 66:33:1. It has a reduced viscosity of 1.4 and an estimated solubility parameter of 8.4. The compositions evaluated also contain a mixture of o,p-toluene sulfonamides (OPTSA) as described above. Certain of the compositions also contain universal carbon black which is an ethylene vinyl acetate copolymer containing 40S carbon black. The compositions and physical properties are summarized on Tab}e 4 below:

x 12 Ex 13 Ex 14 Ex 15 XPN-1576 70 64 58 63.7 U.C. BK 0.3 0.3 YIELD ST.,PSI 3560 3320 2570 3260 (MPa) (25) ' (23) (18) (22) YIELD EL., ~ 25 25 35 35 U.T.ST., PSI 7725 8040 7570 8650 (MPa~ (53) (55) (53) (60) U.EL., % 235 235 275 ,275 FL.MOD.

(MPa) (600) (428) (186) (400) E~ 16 EX 17 XPN-1576 57.7 66.7 U.C. BK 0.3 0.3 YIE~D ST.,PSI 2520 3500 (MPa) (17) (24) YIELD E., % 35 35 U.T.ST., PSI 7000 8040 (MPa) (48) (55) U.EL., % 265 250 FL. MOD. 28K 63K
PSI (MPa) (193) (434) The above examples illustrate that flexible compositions with excellent ~echanical properties can 1 ~51 34 also be achieved with a semi-polar rubber to contribute to hydrocarbon and fluorocarbon resistance. It should be noted that relati~ely good flexibility is achieved.
The compositions evaluated in Table 5 illustrate polyamide compositions containing polac rubber of the present invention. The compositions also include varying amounts of OPTSA plasticizer and an evaluation of the use of universal carbon black master batch.
The examples also illustrate that flexible highly polar blends can readily be pigmented without deterring from properties. For example, highly polar flexible compound as described in Examples 12 through 17, demonstrate very desirable mechanical properties, plus measured fluorocarbon resistance.
Table 5 below describes heat stabilized compounds with an excellent combination of fluQLn~arbon permeation resistance and good mechanical properties.

1 335 1 3~

Ex. 18 MP Ny~n 54.7 S-9721 20.0 U.C. BK 0.3 MFR = 2.4.
FL.ST., psi 2400 (~a) (17) FL MODULUS, p~i 56,000 (MPa) (386) YIELD ST., psi 4000 (MPa) (28) YIELD E., % 30 U. TEN. ST., psi 5300 (MPa) (37) ULT. EL., ~ 270 FLUOROCARBON TESTING: 0.25G. LOSS
AFTER

0.31G. LOSS
AFTER

1 3~5 t 3~

TABLE 5 (Continued) EPM-g-MA 20 20 15 FL.MoDULUS,psi 7LK 97K 3OK
(MPa) (490) (669) (207) FL STRESS, psi (11) YIELD STRESS, 2925 3370 3255 ~si (MPa)(20) (23) (22) YIELD ELONG, ~ 5 5 5 U. TENSILE ST, 4830 6430 7380 psi (MPa)(33) (44) (51) U. ELONG, ~225 290 360 FLUOROCARBOU RESIST:
(SPRINGBORN) WT LOSS.g. 1.3 0.48 0.94 "
The above examples (19 and 20) show that in identical focmulations, replacement of the polac ethylene acrylic acid with a highly polar salt ionomer (high solubility parameter), results in a noticeable resistance to fluorocarbon permeation. rf part of the ionomer is replaced with plasticizer (Ex.21), flexibility is increased, but at a slight sacrifice in resistance to fluorocarbons.

=

~ -23- 1 335 1 34 F LUC)ROCARBON
RES I STANT EXTRUS I ON
G RADES

MP(Nylon 6) 52.6 XPN-1576 52.4 LAT 8040 20.0 EPM-g-MA 12.0 S 1)301 20.0 S-9721 23.0 OPTSA 5.0 OPTSA 5.0 MFR 2.4 3.0 H20% 0.15 0.15 FL. MOD.PSI 62K 27K
(MPa) (428) (186) FL.ST.PSI 2400 1400 (~Pa) (17) (10) YIE~D ST. PSI 3600 2840 (MPa) (25) (20) YIELD EL. % 23 40 U.T. ST., PSI 7250 6630 (MPa) (50) (46) U.EL. ~ 345 345 FLUOROCARBON RESIST:
20 (SPRINGBORN) 39A TESTED 48A TESTED
0.31 G. LOSS 0.21g. loss in 7 days AFTER 19 DAYS 0.35g. 10s8 in 14 days 0.44g. loss in 21 days.
The above examples illustrate that a high level of fluorocarbon resistance can be achieved with a non-polar rubber like EPM-g-MA, by the use of lower modulus Nylon 6~66 with increased ionomer content.

FLEXIBLE FLUOROCARBON
AND HYDROCARBON
RESISTANT COMPOUNDS
WITH LOW LEVELS OF
NoN-roLAR RUBBERS

Comp~: M~ 55%
O~TSA 5%

Ex. 24 Ex. ?5 Ex. 26 Ex.27 EPM-g-MA 20 16 12 8 MFR 0.35 0.41 0.91 1.70 F.MOD., PSI 63K 74K 83K 98K
(MPa) (434) (510) (572) (676) YIELD ST., PSI 3300 3800 3800 3900 (MPa) (23) (26) (26) (27) U.T.S., PSI 5800 5500 6580 6340 (MPa) (40) (38) (45) (44) U.EL., ~ 290 320 300 300 This table shows that highly polar compounds can still be produced but further lower.ing the non-polar rubber by replacing with an ionome~ With as little as 8 wt~, the flex modulus i8 below 100K p~i (690 MPa)-The following table reports. permeation data, as measured by hexane, of the ~arious components used in the compositions of the present invention.
Another useful guide to the de~elopment of flexible polyamide compositions is the measurement of permeability of the indi~idual polymer components, themselves, as shown in Table 8.

' ' -25- 1 33 ~ 1 34 ~AW MATERrAL P~R~EATION D~T~
PER~EABILITY (~EXANE) SAMPLE DESCRlPTIoU GMS - CH/C~ /HRX10 AVER.
Po ly-Latador 8040 E/EA/KA 154.0 147.0 15~.0 153 (66/32/2) Prima E/PtHA 186.0202.0 '97.0 195 (45/55/0.5) Promar E/A~ 2.62.6 2.7 2.6 (93.5/6.5) Surlyn 9721 E/HU/HA-Zn 2.1 2.1 2.2 2.1 (90/4/6) Dumilan 1595 E/VOH(80/20) 0.04 0.06 0.09 .06 Pakto E/E~ (82/18) 40.7 40.5 39.1 40.1 ~ylon XPU-1576 6/66 (85/15) 0.03 0.04 0.02 0.03 ~BLE 9 NQYEL FLUOROC~RBOU
RESIST~T COMPOUUDS
~OUTAIUI~G EVOH

EX.28 E~.29 Ex.30 Ex.31 Ex.32 KP (Uylon 6) 56 56 ~P~-15~6 56 56 56 ~P~-g-~ 13 13 13 10 8 OPTS~ 6 6 6 6 6 KFR 3.00 1.901.10 1/7 2.1 FL.~OD.,PSI 77K 67K 56K 62~ 76K
(MPa) (531) (462) (386) (428) (524) *Trade Marks p ~ ~ -26- 1 335 1 34 The fluorocarbon resistant advantage o~ using an EVOM
was demonstra~ed with hexane permeation testing. These examples illustrate that EVOH can be inco~porated to bestow resistance in nylon 1exible g~ades, ~hile still maintaining low modulus. For a modulus of 76K psi (524 MPa), only 8 wt%
non-polar rubber was required to flexibilize.

EPM-g-MA 25 20 30 E~A 10 5 10 5 F.MOD.,PSI55K. 70K 50K 57K 45K

(MPa) (379) (483) (345) (393) (310) YIELD STR., PSI 3270 3250 3175 2810 3190 (MPa) (23) (22) (22) (19) (22) U.T.S~.,PSI 5740 6800 4920 4700 5800 (MPa) (40) (47) (~4) (32) (40) 2Q U.~LONG, ~240 275 185 200 225 33 39 ~a~et EPH-g-~A
~/EA/MA 30 15 E~A
OP~S~ 3 5 F.MOD., PSI 26K 47K 50K Max.
(MPa) (179) (324) (345) 30 YIELD STR.,PSI 3000 3580 ---(MPa) (21) (25) U.~.ST.,PSI 4800 8340 5000 Min.
(MPa) (33) (58) (34) U.ELONG,~ 200 350 ---What is shown in EX. 33 ~r8. Ex.34and Ex.35 vs.
Ex.36. is that combinations Of ionic polymers can be utilized to balance mechanical properties.

Claims (12)

1. A flexible polymeric composition which comprises a blend consisting of:
(A) from about 50 to 90 percent by weight of a polyamide;
(B) from about 5 to 40 percent by weight of a functionalized rubber phase having a glass transition temperature of 0°C and less capable of being melt processed at from about 218 to 329°C without significant degradation, and having a solubility parameter of less than about 9.0 wherein the functionalized rubber phase is one or more of (b1) a polymer containing at least one monomer selected from the group consisting of acid, ester, anhydride, aldehyde, ketone, alcohol and halide monomers, (b2) an ethylene/C3-C8 .alpha.-olefin, (b3) the reaction product of (b2) and an .alpha.,.beta.-ethylenically unsaturated C4-C8 dicarboxylic acid or derivative thereof; and (C) from about 5 to 40 percent by weight of a functionalized polyethylene having a solubility parameter equal to or greater than about 9.0, wherein the percentages by weight of A + B + C = 100 percent and wherein said blend exhibits a flexural modulus of less than about 118,000 psi according to ASTM D-790.

2. The composition according to claim 1 which further comprises:
(D) from about 0 to 15 percent by weight of a plasticizer, and (E) from about 0 to 15 percent by weight of a polyamide chain extender, wherein the percentages by weight of A + B + C + D
+ E = 100 percent.

3. The composition according to claim 2 wherein said .alpha.,.beta.-ethylenically unsaturated C4-C8 dicarboxylic acid or derivative thereof of (b3) is selected from the group consisting of maleic acid, maleic anhydride, maleic acid monoethyl ester, a metal salt of maleic acid, fumaric acid, fumaric acid monoethyl ester, itaconic acid, vinyl benzoic acid, vinyl phthalic acid, a metal salt of fumaric acid monoethyl ester, a monoester of maleic acid, or fumaric acid or itaconic acid wherein the alcohol is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, hexyl, cyclohexyl, octyl, 2-ethyl hexyl, decyl, stearyl, methoxy ethyl, ethoxy ethyl or hydroxy.

4. The composition according to claim 3 wherein (B) is an ethylene polymer selected from the group consisting of ethylene ethyl acrylates, ethylene vinyl acetates, ethylene vinyl alcohols, ethylene/propylene/diene copolymers, and ethylene/butylene copolymers.

5. The composition according to claim 1 wherein component A is present in an amount of 60 to 90 percent by weight.

6. The composition according to claim 1 wherein the functionalized rubber phase (B) comprises 5 to 20 percent by weight of the blend.

7. The composition according to claim 1 wherein the functionalized polyethylene (C) comprises a copolymer of polyethylene with one or more monomers selected from the group consisting of anhydrides, acid groups and salts thereof, esters, hydroxyl groups, halogen groups, aldehydes, ketones and ethers.

8. The composition according to claim 2 wherein the blend comprises (D) 5 to 15 percent by weight of a plasticizer.

9. The composition according to claim 8 wherein said plasticizer is selected from the group consisting of o,p-toluene sulfonamide, n-ethyl o,p-toluene sulfonamide, n-butyl benzenesulfonamide, phthalate plasticizers, adipate plasticizers, phosphate plasticizers, glycolate plasticizers, trimellitate plasticizers, caprolactam, and polymeric-type permanent plasticizers.

10. The composition according to claim 2 wherein the blend comprises (E) 0.001 to 15 percent by weight of a polyamide chain extender.

11. A fluorocarbon permeation resistant article made from a composition of claim 1.

12. A fluorocarbon permeation resistant article made from a composition of claim 2.