Note: Descriptions are shown in the official language in which they were submitted.
Pcr/uss2/07sn~
W~ ~/06176
TlTLE
~oU6H POLY (META_XYLYLENE ADIPAMIDE) WlTH HlGH FLEXURAL MDULUS
BACKG~OI )~ D 01~ 1 1 IE I~VEI~T101~
This invenlion relales lo an impruve~l po~y.~mi~le composition
~llal is very tougl-, has low m~isture sel~silivity, al~l retains goo(~ nexural
mo(lulus.
Polyami~les are well kn~wn in-~ustrial polymers, ~In~ing
numers)us applicalions in such (liversi~ie~ ~iel~s a~ textile fibers, mol~ling
resins, ~ilms, an~l composiles. The commerciully mosl important polyami~le
is poly(tlex~metl~ylene a~lipami~le), also known as nylon 66; an~l the next
mos~ imporlant commercial polyami~le is poly(~-caprolac~am), also known
nyl~n 6. Ano~her, mucl~ more recenlly commercializell ps~lyami~e is
poly(m-xylylene a~lipami~e), (sl)metimes re~erretl to herein as poly-MXD6),
which is sol~ by ~ subishi Gas Chen~ical Company, Inc. of Japan unsler the
~ra~lename nRE~NY". While bo~h nylon 66 an(l nylon 6 can be ma~e very
~uugh by ~he a~ ion o~ cer~ain rubbery materials, as ~lescribe~l in U.S.
Palent 4,174,358 to Eps~ein, they are somewhat moisture-sensilive an(l have
only a mo~est nex mo~lulus. Poly(m-xylylene a~lipaMille), however, has a
~0 ~lex mo~lulus tbat un(ler ~lry con~itions i5 abou~ 50% higl~er ~han ~hat o~ :
nylon 66. It also is significantly less sensilive lo mois~ure than nylon 66. Yet,
poly-MXD6 h~ts some ~irawbacks, such as having a very low elonga~ion a~
break (less ll~an 3%) an~l being vcry britlle (no~che~l Izo~l value of 2û-25
J/ml. Because ol ~hose, poly-~lXD6 has acllieve~l only a limi~e(l imJus~ri,ll
accep~ance in ~he Uni~e~l Sla~es. Asl(lilives such as, lor exarnple, EPDM
rubber gra~te~ wi~h maleic anlly~ri~le (EPD~/IG) or e~hylene/butyl
acrylate/glyc;~lyl methscry~ate (E~B~/GMf~) ~erps)lymer~ incrc~sc Ihe
toughness o~ poly-~lXD6 when presenl in ~mounls o~ ~5 ~o by weigh~ or less,
~)ut the improvement is ~ar ~rom sJramatic, anLI tlle poly-~lXD6 thus
loughene~ s~ ails in a l~rittle fashion afler impacl.
131en~1ing poly-~lXD6, a~ler prvper soli~l phasing, will~
~PD~G can in some cases improve llle no~che~ Izo(l v~ e of the
~vlyami~le Soli(l ~llash~, is a proce~Jure ~or increasing lhe molec~ r weigllt
of a polynmioe by p:lssing an inerl gas, sucll as nilrogen, througb a be~l of
WO ~3/06176 Pcr/u~ ~n79n,
` 1 1 .~ ~ `3 ~i
resin pe~ets, which is main~aine~ at a temperature bet~lveen the glass
transi~ion temperature an(l t31e melt temperature of tlle polyami~e. Proper
s~ 1 phasing improves the t~ughnes~ Or rubl)er/poly-~XD6 blen~ls by
increasing the mell viscosity of l)oly-~X~6, Ihus il~pr~vin~ ru ~ber
Sull o~ a l)etler ~iScOsity ~ c~ eî~lvee th
polyami(Je. However, a rubber-toughene(l poly-~X~6 with ~ consisten~ly
atlainable notched Izod impact value of over 500 J/m, is IIesirable since this
leads lo non-brillle type of railure upon impact. Yel, using solid phasing
(Joes not achieve this goal for EP~A~G-toughene~1 poly-l~XD6. This may be
1 O (~ue in part to a signi~ican1 recluclion by soli~ phasing of amine en~J ~roup
concentrativn an~l thus reduce~ interactiun of ~mine groups with anhydride
grl)ups of EPOI~C.
~ ccordingly, ~here is a need in the art for improving
poly A~XD6 by increasing its tuughness so that it does not exhibit briltle
15 railure upon impact.
$UI~l~Ry 0~~
According lo Ihe present invenlion, ~here is nowprovided a
lougl1ene~1 poly(m-xylylene adipami~le) c~mposilion ha~ing a flexural
modulus of a~ leasl 2 MPa, when measurerl according lo ASTM D-790 and a
20 nolched impact slrengll~ of al leasl 500 J/m, saio composilion consisling of a
blend of al~oul 5~90% o~poly(m-xyly~ene a(lipami~le) with complementary
amounts of 5-25% of EPDI~ rubber grarteLI wilh about 0.2-5% of maleic
anllyoride or maleic anhydrir~e precursor and al~oul 5-25% of an E/X/Y
terpolymer in whicl~ E slancls for elllylene X slanos for an alkyl acrylale or
ZS methacrylate; :Ind Y strnr~s ror glycillyl acrylale or glycidyl melhacryla~e, an~l
the respective monomer percer1tages are about 4~90%, 10-40%, and 0.5-
~0%, their sum always being 100%; all lhe percen~ages being by weight.
Sueh blends exhibit a greatly improved notche(l Izo-J impact
stren~th, as comparell with uncompounlled poly-MX6 and a higbcr flex
30 modulus Ihan either nylon 66 or nylon 6 toughene(l ~o the samc rJegree.
Further, Ihose blen(ls retain tl-e low mosilure sensilivily of poly-MXD6.
~LEDl?ES~1P~QF T~E INVE~TIQ~
Poly-MXD6 is, as earlier indicated, a commercial product
manuracturer~ by Milsubishi Gas Chemical company, Inc This nlaleri,ll m.ly
~vo 93/06176 Pcr/uss2/07sn7
3 ~? ~i385 6
be available in different gra(les, although lhe parlicul~r gra~le used in the
experimenls reporle-l in Ille examples, l)elow, was (lesignate~l "RENY" 60()1.
Quantitalive a~nalyses eslablislle~ al lllis polylner ha~l an amine en(l grou
concenlr~lion of about 40 e{~uivalenl~ per lo6 y, al~ carboxyl group
concentralion of about 80 equivalenls per lv6 g The relative viscosily of
this polyamide was found to be aboul 19.
EPDM rubber grarle~l wilh maleic anllydri~le or maleic
anhydride precursor can be made acording to the process described in U.S.
Patent 3,884,882 lo Caywood. The ~erm "maleic anhy~Jride precursorn
includes otller unsaturated compountls c~pable or being grafte~l onto ErDM
rubber and of being converle~l un(ler lhe grafling con~ olls~ 3l leaSl in part,
lo maleic anhydri~e or of forming after grafting a succinic anhydride unit.
Typical such precursors include, i.a, maleic acid, fumaric acid, and lower
akyl monoesters of maleic amJ fumaric acids such as, for example, monoethyl
maleate, monomethyl maleate, monoethyl [umarale~ and monomelhyl
tumara~e. EPDM rubbers are well known to the art as terpolymers or
tetr~àpolymers of cthylene wilh one or two ethylenically unsaturaled
monomers and with a diene baving only l)ne terminal double bond.
E/X/Y terpolymers suitablc in lhe present invention also are
well known. They can be made by copolymerization of ethylene with the
other two monomers under pressure in the presence of a free radical
inilialor, al elevale~ lemperatures, preferably about 100-270~C, especially
130~230 C, an~l at elevalul pressures~ pre~erably al leasl 70 MPa, and
especiaJly 140-350 MPa. This is most advanatgeously slone in a continuous
process, adjusting the monomer ratios according to the final comonomer
composition in the tcrpolymcr while taking into account thc differcnt
respcctivc polymerization activities of ~he comonomers. Thc gcncral
proce(lures for making terpvlymers of ethylene wilh ethylenically
unsatura~e~l comonomers are well known, for example from U.S~ Patenls
!~ ~ i '30 4,351,931 lo Armitage; 3,658,741 to Knutson et al.; aml 3,115,485 to Bartl et
al. The preferred comonomer weigbt ratio in the E/X/Y terpolymer is
about 5S-83:15-35:2-lQ especially 57-77:20-35:3-8. Typical such E/XlY
lerpolymers inclu~Je ethylene/n-butyl acrylate/glyci~lyl methacrylate,
~ :,
WO 93/06176 PCI`/VS92/0791"
38S~ ~
etllylene/isobulyl acrylate/glyci~lyl metllacrylale, ethylene/metllyl
me~l1acryl,tte/glycidyl methacrylate, and etllylene/lnethyl
methacryl~tte/glycidyl acrylate terpolymers.
Tll~ preferre(3 weight ralio ur graf~e~l EPDM rubber to E/X/Y
S terpolyrner is 1:4 to 4:1, especially 1:1 ~o 2:1. Tlle prererred we;ght ratio of
poly-MXD6 lo tbe sum of graf~ed EPDM rubber anll E/X/Y terpolymer is
1:1 to 9:1, especially 3:1 to 4:1.
Blending of poly-MXD6 wi~ he olher two components of the
improved compositions of the pre~ent invention can be accomplishe(J in a
conventional manner in standard e~luipmellt, preferably under high shear
an(J ~t an elev~te~l lemperature at whicll all lhree polymers are ;n the melt.
1 ypical such equipment includes single-screw and twin-screw extruders,
rubber mills, am3 Banbury mixers.
The composition of the present invention may be further
blended with small amounts ~f a~l(litional componen~s which woukl no~
detract from the operability of the invention, such as, for example, a~Jitional
plastic or elastomerjc resins, antioxidants, slabilizers~ pigments, plasticizers,
an(l meît processing ai~ls, as is generally known an(J practicetl in the arl of
compoun~ling polymers.
This invention ;s now illustrated by the following examples of
certain preferred eml~ouliments thereof, where all parts, proportions, an~l
percentages are l)y weigh~ unless otherwise in(licale~l.
Exampl~ 9
Poly-MXD6, "RENYI' 6001, was used as received from
Milsubislli Gas Chemical Company, Inc., unless otherwise indicate~J. In
Examplcs 4 and S, it first was solid phascd in a stream of nitrogcn at 190~ C
fur 24 hours. In Example 7, it was first soli(l phased in a 5tream ~f nitrogen
at 180C ~r 3 hours. EPDMG rubber was a graft of 15-2.0% of m;ileic
anlly~ride on a backbone of an elhyleneipropylellell~4-llexadiene 70:24:6
lerpt)lymer made accor(l;n~ to the teachings of U.S. Palent 3,884,882 The
E/X/Y terpolymer was a 66.7:28:5.3 ell~ylelle/n-butyl acrylate/glyciùyl
metllacrylate (E/BA/GMA) terpolymer. These polymers were blen~led for
about 30 s~conds at 270-290 C melt temperature in a Werner ~ Pneiderer
twin-screw extruder. In eacl) case, the blend was extru~3ed into pelle~s an(l
~vo 93/06176 Pcr/Us92/07907
~ il9~ S '~
injection mokle~3 into test specimens, which were subjecteLI to the stan-lar~l
letermination of their mechanical properlies as follows: tensile strength,
ASTM D-638-58T; elongatior~ a~ break, ASTM D-638-58T; flex mo~lulus,
ASTM D-790-58T; nolche~J Izo(l impac~ slreng~h, ASTM D-256-56. All tesl
5 ~3~ta not ol)laine~l in Sl unils have been converle~J to Sl units.
The results of lhese experimenls ~re repor~e~ in lhe rollowh
Table 1:
WO 93/061 76 ~ PCr/US92/0791'--
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O H ¦ H O i` / O N O ~b
a
~ _ _
D X . ~ t~
;4 E ~ 1 N
o o~
~r~
o Cl~ o t~
a~
X L ~ `~
~ ~ ~ o
~: ~
., .
: ~ ~ ~ ~
~ _1 -t
s ~ N .q
O h
1~ ~ '
u~ o Ir~ o ,1 ul o
~O
. ,~ ,~ u~ o ~ l o
.
x Z
~Ivo 93/06176 ~i 1 9 8 5 6
The resulls of the above Ex~m~le~ I ~n~l 2 SllOW tha~ using
EPDMG ~lone or a cl)mbinati~ EPDM ~n~l EPDMG, wilh a total
combine(l rul)l~er content of up lo 25% of lhe wei~ht Or llle blen~ls, tlle
loughene-J poly-MXD6 still exl~il)i~ed hriltle r~ilure UpOIl impact. Wllile tlle5 30:70 EPDMG:poly-MXD blen~ Or Example 3 ~lid exhil it non-brittle railure
upon impact, this was acllievelJ at a signiricanl sacrifice Or the unique high
llex mo(lulus of Ihe polyallli(le. I~y contras~"l lypic~l nyloll 6 or nyloll 66 will
m)rlllally exhil)it noll-brittle lailure upon im~)~ct ;n the presence of only 20%
of EPDMG or less.
Examples 4 and 5 sllow that solid phasin& poly-MXD6 al
190 C hl a stream of nitrogen for 24 hours f~ile~l to improve the touglllless
of the rubber/poly~llli(le blen(ls. Tllis w~s so in spile of llle fact that solid ``
phasing increases poly-MXD6 relalive viscosi~y from abollt 19 to over S().
Under these con~litions, tbe amine end group concentrati~n is reduce~l rrom
about 40 to abouî 10 equiv~lents per 106 8- Example 7 sllows that soli~l
phasillg poly-MXD6 in a stream of nitrogell aî 180C for 3 l~ours (lid
improve lhe loughness of tlle rubber/poly-MXD6 blends but the molle of
impacl failure still was brittle.
Examples 6 an(3 8 show the exceptional improvement of
20 notched Izod impact strenglh obtained with a combination of grafted EPDM
rubber and an E/X/Y terpolymer according to the present invention.
Example 9 shows that a 20:80 blend of E/BA/GMA
terp~lymer witll poly-MXD6 alone, while having good elongation properties,
has a very poor notclled Izod impact strength.
