Note: Descriptions are shown in the official language in which they were submitted.
1 335 1 34
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~
-5-
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
--6--
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:
1 3351 34
-7-
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
-8- 1 335 1 34
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
9 1 335 1 34
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~
-12-
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
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~
-15-
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:
1 335 1 34
-16-
TABLE 1
Comp L comP 2 Comp 3 Ex 1
xrN-l576 70 60 50 60
EPM-g-MA 30 40 50 30
5 EAA L0
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
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 :
-
1 335 1 34
- 17 -
TABLE 2
Ex 2 Ex 3 Ex 4 Ex 5
XPN-1576 50 50 50 50
EPM-g-MA 35 25 20 10
EAA 15 25 30 40
FL.MOD.
PSI 42K 50K 55K 70K
(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
- 18 -
TAB LE 3
Ex 6 EX 7 EX 8 EX 9
XPN-1576 60 60 60 58
EPM-g-MA 15 10 10 10
S 9721 15 20 ~5 15
OPTSA 10 10 15 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.
PSI 46K 43K 36K 33K
(MPa) (317) (297) (248) (228)
EX 10 EX 11
15 XPN-ls76 58 58
EPM-g-~L~ 16 10
S 9721 16 17
OPTSA 10 15
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.
PLES 12 - 17
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~
--19--
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:
TABLE 4
x 12 Ex 13 Ex 14 Ex 15
XPN-1576 70 64 58 63.7
E/EA/MA 30 30 30 30
OPTSA 6 12 6
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.
PSI 87K 62K 27K 58K
(MPa) (600) (428) (186) (400)
E~ 16 EX 17
XPN-1576 57.7 66.7
E/EA/MA 30 30
OPTSA 12 2
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
-20-
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~
-21-
TABLE 5
Ex. 18
MP Ny~n 54.7
E/EA/MA 20
S-9721 20.0
OPTSA 5 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
13 DAYS
0.31G. LOSS
AFTER
19 DAYS
1 3~5 t 3~
-22-
TABLE 5 (Continued)
19 20 21
XPN-1576 55 55 60
EPM-g-MA 20 20 15
5 EAA 25
S-9721 25 15
OPTSA 10
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)
DAYS 13 13 14
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
TABLE 6
F LUC)ROCARBON
RES I STANT EXTRUS I ON
G RADES
2223
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.
-24- 1 335 1 34
TABLE 7
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
S-9721 20 24 28 32
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
TABLE 8
~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
EVOH 25 13 13 14 15
~P~-g-~ 13 13 13 10 8
S-9721 12 12 14 14
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.
TABLE 10
COMBIUATIOUS OF POLAR ETHYLENE C0POLYMERS
33 34 35 36 37
10 XPN-L576 55 55 50 55 52
EPM-g-MA 25 20 30
E/EA/MA 20 20
S-9721 10 20 20 20 15
E~A 10 5 10 5
OPTSA 3
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
XPN-1576 52 55
EPH-g-~A
~/EA/MA 30 15
25 S-9721 15 25
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.
