Note: Descriptions are shown in the official language in which they were submitted.
i34006~
Fiel ~ of the Invention
This invention relates broadly to a novel graft copolymer
capable of imparting to a polyolefin, when blended therewith, high
tensile modulus and high resistance to sagging without increasing melt
viscosily, and to a method of making the same.
More particularly, the invention relates to a polymerized olefin
having grafted thereto, by covalent bonding, a polymeric methacrylate
chain of relatively high molQcu~ weight. The methacrylate chain has a
weight average molecular weight (Mw) of at least 20,000 and
advantageously between about 30,000 and 150,000.
In the method of manufacturing the grafted copolymer, a non-polar
polyolefin, ple~ral ly polypropylene or polyethylene, is introduced into
an inert hydrocarbon solvent which dissolves (or swells) the polyolefin,
by heating to a temperature at which the polyolefin is dissolved. While
agitating the solution, methyl methacrylate (MMA) monomer, together
with an initiator which generates a constant, low radical flux
concentration sufficient to initiate polymerization of the monomer at the
temperature of the solution and the formation of the covalent bond, is
gradually added. The polyolefin with a side-chain grafted thereto is
ll,er~a~ler separated from the solvent by volatilizing the solvent,
preferably in a devolatili~ extruder. The graft polymer is then
blended with a suitable polyolefin such as polypropylene or
polyethylene, and extruded into a desired shape.
-k
. ~ .. .. " , , .... ~ .. ", . ,~ ,......... . .
~1!!9S.;
R~cK~r~ l INn ~F THF INVFNTION
Non-polar polyolefins, especi~lly polypropylene and polyethylene
and mixtures in various low-density, high-density, and linear low-
density form, are major articles of commerce for a wide variety of uses.
Nevertheless, there exist specialty needs for which the marketplace has
not provided a s~tis~r-otol~r answer. Among these are to overcome the
difficulty of ll.~rmoforming and processing of the polyolefin, especially
unfilled, in a molten or semi-molten form (subst~ntially above its melting
point); the polymer tends to sag readily under its own weight because it
o exhibits an undesirably low stiffness, and to form shapes of grossly non-
uniform thicknesses upon thermoforming. Attempts to correct same by
increasing the molecular weight lead to difficulties in processing the
higher molecular weight polymer not encountered with the lower
molecular weight grades.
For the isot~tic polymer of butene-1, known also as polybutylene,
the low melting point has made difficult the crystallizing of the polymer
after processing and obtaining the enhanced performance and
handling properties crystallization imparts. Satisfactory nucleators have
not appeared in the marketplace.
Means have also been sought to improve the toughness or impact
strength of polypropylene, for instance. Use of copolymers or ethylene-
prowlene rubber modified polypropylene has improved toughness, but
at the cost of even lower stiffness values, and lower values of heat
distortion resistance. It would be desirable to combine impact
performance of the copolymers with stiffness and heat distortion
behavior of the ho~opolymer polypropylene resin.
Grafting of monomers careble of vinyl polymerization, such as
styrene, methyl methacrylate, and the like, onto polyolefins such as
polyethylene, polypropylene, ethylene-propylene copolymers, and
. ,... . . ., ,. . . ~ .
1~40l~6~
ethylene-propylene-diene terpolymers has been studied almost since
the discovery of routes to prd.,~tical preparation of such backbones.
Grafting onto solid polymer by vapor-phase polymerization, by reaction
in an extruder, by peroxi~l~lion of the olefinic backbone, and grafting
onto pendant double bonds are all routes which have been attempted.
There still exists a need for a route which allows for grafts of relatively
high molecular weight, with relatively good grafting efficiency (i.e.,
lov.-er~d fo""alion of un~tlached polymer molecules), freedom from gel,
and a practical means for preparing and isolating the graft polymer in
o an efficient and lower~ost mannsr.
Blends of two or more polymers have often been made, for
example in attempts to combine desirable properties of the individual
polymers into the blend, to seek unique properties in the blend, or to
produce less costly polymer products by including less expensive or
scrap polymers in the blend. Co~lpAt~ polymers tend to form blends
that contain small domains of the individual polymers; in the case of
~miscible~ polymers these occur at the molecular scale, resulting in
properties usually considered characteristic of a single polymer. These
may include occurrence of a single glass-transition temperature and
optical clarity. Such blends are frequently termed ~alloys." Compatible
polymers that are not strictly miscible, as described above, nevertheless
tend to form blends with properties that approach those of the miscible
blends. Such properties as tensile strength, which rely upon adhesion
of the domains to one another, tend not to be degraded when
compA~ible polymers are blended.
Unfortunately many polymers are poorly compatible with one
another. Poor co~ ,atibility cannot necess~rily be predicted accurately
for a given pol~",er co",bination, but in general it may be expected
when non-polar polymers are blended with more polar polymers. Poor
coi"p~tibility in a blend is apparent to those skilled in the art, and often
13400fi~
evidences itself in poor tensile strength or other physical properties,
es~:~"y when compared to the component polymers of the blend.
Microscopic evidence of poor compAtibility may also be present, in the
form of large, poorly adhered domains of one or more polymer
cG,-,ponants in a matrix of another polymer component of the blend.
More than one glass-transilion temperature may be observed, and a
blend of otherwise transparent polymers may be opaque because the
domain sizes are large enough to scatter visible light.
Much research has been directed toward finding ways to increase
o the compatibiUty of poorly compatible polymers when blended.Appr~,achas that have been used include adding to the blend polymers
which show compatibility with the other, mutually incompatible
polymers; such added polymers act as a bridge or interface between
the incompatible components, and often decrease domain size.
Chlorinated polyethylene has been used as such an additive polymer,
espedally in blends of polyolefins with other, poorly compatible
polymers.
Graft polymers, as of incompatible polymers A onto B, are known
to aid in blending polymers A and B. Such graft polymers may also
serve to aid in blending other incompatible polymers C and D, where A
and C are cG",palible and B and D are compatible.
What has also been difficult to predict in polymer science is the
extent to which such a graft polymer will be effective in enhancing
desirable properties of the blend over those of the incompatible blend
alone. Conse~ ently, those skilled in the art have had to treat each
combination of graft polymer and other component polymers of a given
blend as a spQ~ case, and determine experimentally whether an
improvement in such properties as tensile strength could be obtained
by adding a specific graft polymer to a specific blend.
0 6.~
pFI FVANT ART
U.S. Patent No. 4,094,927 describes copolymers of higher alkyl
m~,~l,aclylates with (meth)acrylic acid as melt strength additives, foam
slal,ili~ers, and processing aids for polypropylene. Such polymers,
however, are not fully cG.~,pali~le with polypropylene and the additive
will tend to plate out and foul equipment during such operations as melt
calendering.
U.S. Patent No. 4,409,345 describes polyolefin modified with a
polymerizable unsaturated carboxylic ester in affording improved
o p,ucessing of mixtures of polypropylene, high density polyethylene, and
finely divided vegetable fibers. The patent appears only to demonstrate
reinforcement by the fibers which are bonded to the polyolefin by the
graft copolymer. All examples are limited to "grafts~ of maleic anhydride
or acrylic acid, wherein the material grafted is of a molecular weight
cGr.dspGnding to a small number of monomer units.
South African Patent No. 826,440 describes "improved melt
viscosity~ (higher melt viscosily under low shear conditions while
retaining the low melt viscosily at high shear rheology behavior of the
unmodified polypropylene) and improved thermoforming characteristics
for blends of polypropylene with certain salts of acid-modified propylene
polymers.
U.S. Patent No. 4,370,450 describes modification of
polypropylene with polar vinyl monomers by polymerization in aqueous
suspension containing a swelling agent at temperatures above 85~C
2~ with a radical chain initiator having a half-life of at least 2 hours in the
temperature range 80-135~C. The patent does not desc,ibe direct
solution grafting, stating such yields ~only relatively low degrees of
grafting~. Hydrocarbons are listed as examples of swelling agents.
1340065
U.S. Patent No. 4,161,452 describes only grafts of unsaturated
carboxylic acids or anhydrides and esters of (meth)acrylic acid onto
ethylene/propylene copolymers in solution in the presence of a free-
radical initiator c~p~hle of hydrogen abstraction at temperatures
between 60 and 220~C. An oil soluble polymer is required.
U.S. Patent No. 4,595,726 describes graft copolymers of C2-C6
alkyl "~tl,ac,ylates onto polypropylene via a solvent-free vapor-phase
pol~",eri~dtion wherein the molecular weight of the graft and the
number of ~ t6~ chains are controlled to yield the desired (although
o undefined) length and number of chains for utility in adhesive
applications between polypropylene and more polar substrates. The
patent diccloses that similar grafts can be made from methyl
methacrylate, but do not exhibit the desired adhesive properties. The
patent requires polyme,i~tiGn below the softening point of
polypropylene, which is not defined in their patent, which is known to be
IowGr~.l by the presence of monomers, and for which no temperature
higher than 1 40~C is exemplified, and in the absence of solvent. There
is no indication or suggestion that a relatively high molecular weight
chain is covalently g.dll~ to the polyolefin. Moreover, the radical flux
generated appears to be too high to form a high molecular weight, e.g.
greater than 20,000, chain.
U.S. Patent No. 4,692,992 describes grafting at temperatures
betwGen 60 and 160~C while maintaining the olefin polymer dissolved
in a solvent which is a mixture of a hydrocarbon and a ketonic solvent,
the grafted polymer pr~cipilaling upon cooling the reacted mixture
below 40~C. n~nctiQn co,~ditions for achieving high molecular weight
or the advantage in conducting the reaction in the presence only of a
solvent of low chain transfer activity are not disclosed.
U.S. Patent No. 3,86~,~65 only describes melting of polyolefins in
an extruder, followed by g.dfling of unsaturated acids to achieve
13qO065
~improved rheology~ as defined in South African Patent No. 826440,
supra.
U.S. Patent No. 3,886,227 discloses (but does not exemplify for
the esters) grafting of unsaturated acids and esters to form a material
useful as a modifying agent for polypropylene. The grafting is
conducted in an extruder, and they also disclose that the molecular
wei~ht of the backbone polypropylene polymer be lowered by
degla~atiGn during the grafting process, conducted at a temperatur
above 200~C. It describe6 blending with polypropylene and the
resulting modification found, such as nucleation, lack of warpage on
molding, and the like. Although improvement in heat distortion
temperature is noted, there is no disclosure of improved rheological
performance at the tel"perdtures required for thermoforming and the
like.
Japanese Kokai 59-164347 describes grafts of unsaturated acids
or their derivatives (including esters) at very low graft levels (10-5 to 10-
8 g equivalents per gram of polyolefin), blends of the grafts with
polyolefins, and their use in affecting surface tension in the molten state
of the polyolefin while not affecting high-shear viscosity, making the
blends useful in, e.g. blow molding of bottles.
Kallitis et al., FIIr. Pr~ymer J.. 27, 1 17 (1987) describes ethylene-
propylene polymers as nucleating agents for polybutylene. They do not
cJesc,ibe or su~gest the utility of the polypropylene/methacrylic grafts of
this invention.
Reike and Moore, in U. S. Patent No. 2,987,501, disclose grafts of
polymers of vinyl monomers onto polyethylene or polypropylene by
oxidizing the polyolefin with fuming nitric acid or nitrogen tetroxide,
followed by heating the aclivated polyolefin with the vinyl monomer.
13400fi~i
The reference exemplifies grafting methyl methacrylate onto
polyethylene and polypropylene.
Japanese Kokai 223250/87 dicclQses compatibilizing a polyolefin
and a polyamide using a reaction product of an unsaturated carboxylic
acid or its derivative y- fled onto a mixture of polyolefin and polyamide,
that is, the re&,tion product is formed in the presence of a mixture of two
or more polymers. The amount of acid or derivative reacted with the trunk
poly.-,ers is less than 10%, and it is clear from the only examples present,
which utilize unsaturated acids which do not homopolymerize, that what
o is attached or grafted are low-molecular-weight moieties,. They disclose
reaction conditions, including relatively low levels of unsaturated acid
and relatively high levels of peroxide, which would lead one away from
achieving the molecular weights of the grafted chains disclosed below as
part of the present invention. A particular modifier disclQsed by this
reter~nce, formed by rea~ti"g two non-polymerizable acids with a mixture
of four trunk polymers, affe~ts the compatibility of the polyamide and
polyolefin. However, the comparative data suggest that a reaction of the
acids onto polypropylene alone is not an effective compatibilizer for the
two resins, and shows that graft polymers of low levels of low molecular
unsaturated acids or derivatives are not effective in compatibilizing
polyamides with polyolefins.
Japanese Kokai 86040/87 directed to polymer adhesives,
~;scloses an olefin polymer ~I,esive modified with a carboxylic or
carboxylic anhydride group, further reacted with a polyolefin having
alcohol functionality, and still further reacted with an aromatic acid halide.
Boutevin et al., in Ar~ew~ndte l~ kromolekular Chemie. Vol. 162,
page 175 (1988), .J;~,lose the preparation of a graft polymer of
poly(methyl methacrylate) onto a polyethylene trunk by ozonolysis of a
low-density polyethylene followed by heating the activated polyethylene
in the presence of methyl methacrylate. They disclQse grafts of methyl
13400~S
methacrylate having a number-average molecular weight up to 21400
and the use of such grafts as polymeric emulsifiers or c~",p~ibilizers for
mixtures of low-density polyethylene and poly(vinyl chloride). They
report that the co,llpat;biliz d mixture has a distinct increase in the stress
required to break it and a decrease in the domain sizes in the blend.
They also report apprer~ ls degradation of the polyethylene molecular
weight when it is ozonked prior to grafting. This reference does not deal
with higher molecular weights nor does it provide any indication that the
graft polymer might be effective in reducing sag of a polyolefin matrix
polymer or otherwise imparting desirable rheological effects to a
polymer.
Thus the art has described means for preparing grafts of methyl
methacrylate homo- and copolymers upon polyolefin substrates but has
not recognized the advantages of the polymerization process herein
described for a rapid efficient prodlJction of novel high molecular weight
grafts without gel and with ease of product isolation. The art teaches that
certain grafts may be blended with polyolefins but has not recognized
the unexl~e~1~1 utility of the novel graft polymers of this invention as
having positive effects on both low-shear melt and solid-state properties
espec~ y with little or no effect on the high-shear performance. The art
also has not reco~ni~e.~ or identified the positive effects on sag
resistance imparted by the present grafts.
It is thus an object of this invention to provide an improved process
for the manufacture of novel graft polymers of methacrylic esters onto
'5 polyolefin subsb~es. Another object is to provide graft copolymers of at
least one chain of ",etl,a.;lJ~lale polymer of relatively high molecular
weight i.e. at least ~0 000 onto a polyolefin homo- or copolymer
substrate. Yet another object is to provide such graft copolymers which
serve as compatibilizing agents for blends of polymers which are
otherwise poorly cor"patibb. It is a further object to provide blends of the
.,. ~ ... .~ . ...
13100~5
graft copolymer with a polyolefin matrix which exhibit improved physical
performance in the melt, upon cooling, and in the sold state.
Further objects and advantages of this invention will appear as
this speci~i~lion progresses.
.~UMMARY OF THF INVFNTION
Broadly, the aforesaid objects and advantages are accomplished
by grafting onto a non-polar polyolefin trunk in solution, at least one
chain which is of a polymer having a weight average molecular weight
greater than about 20,000, and present in a weight ratio with the
polyolefin of from about 1:9 to 4:1. The graft polymer is derived from at
least about 80% of a monomer of a methacrylic ester of the formula
CH2 = C(CH3)COOR, whera R may be alkyl, aryl, substituted or
unsubstituted, and less than 20%, based on the total monomer weight, of
an acrylic or styrenic monomer copolymerizable with the methacrylic
ester. This is accomplished by adding the methacrylate monomers to a
solution of the polyolefin together with an initiator which generates a
constant, low radical concen~ralion, or radical ~flux", at the solution
temperature. These r~ initiate polymerization of the monomer and
cause formation of a covalent bond with the trunk.
The resulting copolymer product, hereinafter referred to as
concentrate, may be blended with polyolefin either as a result of the
manner by which it is made, or after it is made. It may be extruded into a
desired shape sither directly, or after pelletization. In either case, the
resulting blended product exhibits a relatively high tensile modulus and
high sag resistance ~vithout an increase in melt viscosi~y, as compared
with similar ungrafted polymers, viz: polyolefins without a high molecular
weight chain or chains covalently bonded thereto.
1340065
The concentrate may also be blended with other polymers than
polyolefins, and particularly with mixtures of two or more polymers which
are poorly con-patible with one another, and which may or may not
include polyolefins, to improve the compatibility of the resulting mixture.
The invention also relates to a process of making such a
copolymer having a relatively high weight-average molecular weight
(Mw) polymer chain. Briefly, the prt,cess according to this invention
involves dissolving or swelling the polyolefin in an inert hydrocarbon
solvent, and heating to dissolve the polyolefin, i.e. at least about 1 40~C.
While agitating the solution, a monomer is introduced, together with an
initiator which generates a constant, low radical flux at the temperature of
the solution; the radicals initiate polymerization of the monomer and
formation of a covalent bond therewith on the polyolefin trunk. The
reacted mixture may be allowed to solidify by removal of the solvent. The
resultant product, the concentrate, consists of the polyolefin with the
chain grafted thereto, unreacted polymer, i.e. polyolefin without the chain,
and ungra~leJ methacrylic ester polymer. It may be pelletized, blended
with another polyolefin and extruded into desired shape. Alternatively
the reaction mixture may be extruded directly in a devolatilizing extruder
to volatilize the solvent and residlJel monomer, and thereafter blended
with a polyolefin and extruded to form article in such form as sheets,
tubes and the like.
nFTAII Fn nF~;:CRlPTlON
In the following, LDPE is low-density polyethylene, usually
branched, of density of about 0.91 to about 0.94 g/cc; HDPE is high-
density polyethylene of a density above about 0.95 g/cc; LLPDE is linear
low-density polyethylene of density about 0.91 to about 0.95 g/cc; EPDM
inc4~des nubber terpolymers of ethylene, propylene, and a non-
1~40~65
conjug~ted diene monomer, such as 1,4-hexadiene or
ethylidenenorbornene.
The term "polar suL.st,ate~ or ~non-polar polymer, as used herein,
is difficult to define in quant;ld~ive terms. By "non-polar" is meant
polymers which are predominantly formed from monomer units of mono-
or di-olefins. ~Polar~, as generally underslood in the polymer art, would
refer to monomers or polymers which contain an oxygen, nitrogen, or
sulfur-containing functionality. Thus, methyl methaclylate, acrylonitrile,
and vinyl phenyl sulfone are ~polar~ monomers, whereas polypropylene
is a ~non-polar polymer.
The polymers to be modified in the grafting process include the
non-polar olefin polymers and copolymers. Included are polypropylene,
polyethylene (HDPE, LDPE, and LLDPE), polybutylene, ethylene-
propylene copolymers at all ratios of ethylene and propylene, EPDM
terpolymers at all ratios of othylene and propylene and with diene
monomer contents up to 10%, poly(l-butene), polymethylpentene,
ethylene-vinyl acelale copolymers with vinyl acetate contents up to 25%,
ethylene-methyl acrylate copolymers, ethylene-methyl methacrylate
copolymers, and ethylene-ethyl acrylate copolymers. Also included are
mixtures of these polymers in all ratios.
Usable graft copolymers include those with ratios of
polyolefin:acrylic polymer or copolymer that vary from 20:80 to 80:20.
The molsculer weight of the polyolefin polymer which forms the
trunk of the graft copolymer should be high enough to give a large
amount of non-polar polymer when grafted, but low enough so that most
of the graft copolymer has one acrylic polymer chain grafted to each
polyolefin trunk chain. A polyolefin trunk having a molecular weight of
about 200,000-800,000 Mw is e.speci~lly preferred, but polyolefins having
a mo'ec~ weight of about 50,000-200,000 can be used with some
1 3 i O ~ fiS
beneficial effect. In ~eneral, a ~raft copolymer imparts greater mslt-
rheolo~y i.,-prove...~nt to ~ hi~h-molecular-weight polyolefin. This is
especially true when the polyolefin tnunk of the graft copolymer is of
relatively low molecular weight.
Me~t flow rate (mfr) is well known to correlate well wiih weight-
average molQcu'~ wei~ht. The profer.dd range of mfr values for the
polyolefin trunks used in preparin~ the ~rafl copolymers of the present
invention are from about 20 to about 0.6 ~/10 minutes as measured by
ASTM Standard Method ~1238.
0 The pre~er-dd .,.o,~o,--er is methyl methacrylate. As much as 100%
of this, or of other 2 to 4 carbon alkyl methacrylates, can be used. Up to
20% of hi~h alkyl, such as dodecyl and the like, aryl, such as phsnyl and
the like, alkaryl, and such as benzyl and the like, and/or cycloalkyl, such
as cyclohexyl and the like, methacrylates can be used. In addition, up to
j 20% (preferably less than 10%) of the following monomers can be
incorporated with the .netl~clylate esters which form the major portion of
the monomer: methacrylic acid, methacrylamide, hydroxyethyl
methacrylate, hydroxypropyl methacrylate, alkoxyalkyl ~"etl)acrylates,
such as ethoxyethyl methacrylate and the like, alkylthioalkyl
methacrylates, swh as ethylthioethyl methacrylate and the like,
methacrylamide, t-butylaminoethyl ~~,~ll-acrylate, dimethylaminoethyl
methacrylate, dimethyla,--~ ~oprupyl methacrylamide, glycidyl
methacrylate, methacryloxypropyltlietl.oxysilane, acrylate ~,~o,-G,-,ers
tsuch as ethyl acrylate, butyl acrylate and the like), styrene, acrylonitrile,
t 25 acrylamide, acrylic acid, acryloxypropionic acid, vinyl pyridine, snd
~vinylpyrrolidone. In addition, as much as 5% of maleic anhydride or
itaconic add rnay be~l~sed. It is important that the chain t~,~sfer of the
poly,..erizing chains to its own polymer be minimal relative to transfer
with the polyolefin chains for the efficient prod~ction of homogeneous non-
3o ~elled graft polymer in ~ood yield.
~, ':
1~40~5
The molecu'~r weight of the acrylic graft as measured by the
weight average molecular weight of the un~rafted co-prepared acrylic
polymer may be about 20,000 to 200,000. The preferred range is 30,000
to 150,000.
The process of graft polymerizing the monomer leads to the
prodoction of ungrd~leJ and y~ ecl material. The amount of grafted
",dte,ial is in the range of 5% to 50% of the total acrylic polymer or
copolymer pro~uced The graft copolymer is prepared in a process that
polymerizes the monomer in the presence of the non-polar polyolefin.
The process is con~u~ted in a solvent which swells or dissolves the non-
polar polymer. The solvent is also one that has no or low chain transfer
ability. Examples include non-branched and branched aliphatic
hydrocarbons, chlorobenzene, benzene, t-butylbenzene, anisole,
cyclohexane, naphthas, and dibutyl ether. Preferably, the solvent is easy
to remove by extrusion devolatilization, and therefore has a boiling point
below 200~C, preferably below about 150~C. To avoid excessive
pressure, a boiling point above about 1 00~C is also preferred.
The final solids content (which includes polyolefin and acrylic
polymer) depends on the viscosity and the ability to mix well. The
practical limits are 20% to 70% but the solids content can be as high as is
consistent with good mixing for economy. Preferably, the solids content
falls in the range of about 35% to about 60%.
A gradual addition or multicharge addition of the monomer is
preferred. Optionally, the monomer charge need not be the same
throughout, for example, the last 0-20% may contain all of the monomer
used in minor amount to concentrate that monomer in one portion of the
polymer.
The temperature during the polymerization can be in the range
110 to 200~C but the p~efe~ d range is 130 to 175~C. Especially
14
1 3 4 0 0 ~
preferred is 145 to 160~C. The pressure can be atmospheric to
supGr~t",ospheric, or as high as 2100 kPa or whatever is necessery to
keep the reaction mixture in the liquid phase at the polymerization
temperature.
The unreacted monomer concentration should be kept low during
the reaction. This is controlled by balancin~ the radical flux and the
monomer feed co"dilions.
For polymerization, oil-soluble thermal free-radical initiators are
used. Those that work in this process are those with a one hour half life
o at about 60~ to about 200~C. The preferred ones have a one hour half
life in the range 90 to 170~C. Suitable free radical initiators include
peroxy initiators such as t-butyl peroxypivalate, lauroyi peroxide, 1,1,3,3-
tetramethylbutyl peroxy-2-~thyl hexanoate, 2,5-dimethyl-2,5-bis(2-
ethylhexanoylperoxy)hexane, acetyl peroxide, succinic acid peroxide, t-
butyl perocto~te, benzyl peroxide, t-butyl peroxyisobutyrate, t-butyl
peroxymaleic acid, I-hydroxy-l-hydroperoxydicyclohexyl peroxide, 1,1-
bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, t-butyl peroxycrotonate,
2,2-bis(t-butylperoxybutane), t-butylperoxy isopropyl carbonate, 2,5-
dimethyl-2,5-bis(benzoylperoxy)-hexane, t-butyl pefacetate, methyl ethyl
ketone peroxide, di-t-butyl diperoxyphthalate, t-butyl perbenzoate,
dicumyl peroxide, 2,5,dimethyl-2,5-di(t-butylperoxy)hexane, 2,4-
pentanedione peroxide, di-t-butyl peroxide, 2,5,-dimethyl-2,5-di(t-
butylperoxy)-hexyne-3, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene
hydroperoxide, 2,5-dimethyl-2,5-di(hydroperoxy)hexane, t-butyl
hydroperoxide, t-butyl cumyl peroxide, p-menthane hydroperoxide and
azo-bis-isobutyronitrile.
The initiator is introdlJced together with the monomer during the
polymerization in a manner to maintain a fairly constant radical flux
during most of the polymo.i2alion. This is done to achieve the correct
l~qo~ s
high molecul~ weight, a high graft efficiency, the desired molecular
wei~ht distribution, and freedom from gel.
Radical flux can be defined as the calculated rate of formation of
free radicals, expressed in equivalent of r~diG~ls per liter per minute.
While not being c~r~hlQ of being measured experimentally, this may be
calculated from the known rate of deco",?osilion of the free radical
initiator present at any time, and its inslanlaneous concentration.
Decomposition rates for in~tiators are determined from published
literature, and the concentration is either a known constant, as in
continuous feed of initiator, or can be c-'cul~ted (for a single charge of
initiator) from the known decomposition rate constant and the time
elapsed since feed.
Good results are achieved when a uniform radical flux is
",aintained and the radical flux is c~lcul~ted to be in the range 0.00001
to 0.0005 equivalents of radicals per liter p~r minute. The preferred
range is 0.00002 to 0.0002 equivalents of radicals per liter per minute.
The radical flux is dependent on the specific initiator utilized, its
concentration and rate of decomposition, and the reaction temperature
chosen. The rate of .Je~,nposition can be found in tabulated data, such
as in ~The Polymer H~ k", 2nd Edition, ed. Brandrup and îmmergut,
Wiley and Sons, New York (1975), or provided by the manufacturer.
Even if the exact rate constant at the temperature of interest is not known,
often activation ener~ies are supFlied from which the rate can be
~Icul~ted The radical flux is:
Radical flux = 2(kd)(60)(1)
where kd is that rate eonstant for decomposition of the particular initiator
in units of inverse seconds, and I the concentration of the initiator in
moUliter. In a batch reaction, I steadily decreases from lo~ the initial
charge, and the radical flux is not constant. When initiator is continuously
16
.. .. .. .. ,~ ~ , , , ,. ~, , .
13~06~
fed, a calculation must be made to determine the instantaneous
concentration of initiator, but the value is much more constant than in a
batch reaction, espec~~"y with careful control of initiator feed.
The process may be run in a semi-continuous or continuous
manner. Monomer, solvent, and initiator may be added by means similar
to those descnbed above. Polymer may be separately dissolved in
solvent and added at a rate essentially equivalent to that of product
removal, or polymer may be melted and added as a solid to the reaction
by means of an extruder.
o After the polymerization, a hold time may be used. Then the
mixture is devolatilized to remove solvent and any unreacted monomer.
Acceptable devolatilizing devices include a devolatilizing extruder, a
rotary film evaporator, or any other convenient stripping device as known
in the art. The polymerization reaction mixture may be conveyed to the
devolatilization appar~t.ls as a batch or continuously.
Prior to, during, or after the devolatilization step, appropriate
additives may be admixed into the graft copolymer solution/suspension
which are desi~d to be present in the isolated gra~t copolymer. If such
additives do not affect the grafting reaction, they may be added prior to,
during, or after the polymerization process. Such additives may also be
added when the graft copolymer is blended with the matrix polymer.
Such additives may include stabilizers against light or heat, such as
benzotriazoles, hindered amines, alkyl polysulfides such as dialkyl
disulfides, and the like, lub~cants, or plasticizers; flame retardants; and
the like. Preferred is the addition of a disulfide, such as di-n-dodecyl
disulfide or di-t-dodecyl disulfide and the like at levels between about
0.001% to about 0.05~h by weight of graft polymer, based on the weight
of graft copolymer plus matrix polymer, to stabilize the acrylic portion of
the graft copolymer against thermal degradation during melt processing
while admixing into the matrix or blending and extruding.
- 1340065
A second class of stabilizer is the tris(polyalkylhydroxybenzyl)-s-
tri~inetriones. Preferred is tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-
s-triazine-(1H, 3H, 5H)-trione, at levels from about 0.001 to about 0.1%
by weight, based on the total polymer weight.
Stability may also be imparted to the acrylic portion of the graft
copolymer by including an alkylthioalkyl (meth)acrylate, preferably
ethylthioethyl ",e~l,a~rylate, with the acrylic monomer or monomers
during the graft polymsrization.
The product is then isolated by stranding, cooling, chopping,
o drying, and bagging, or other known collection techniques.
The polyolefin and the graft copolymer concentrate may be
blended by mixing the dry feed materials and extruding either directly to
form a film, sheet or the like, or by collecting the blend and reprocessing
it into the desired article, or by adding the polyolefin in the course of the
devolatilization.
Polyolefins are often produced with one or more stabilizers to
prevent degradation of the polymer appearance or physical properties
during prucessing and/or end use. Such stabilizers may include metal
salts such as metal stearates, which act as acid acceptors, hindered
phenols, which act as anti-oxidants, and sulfur-containing organic esters
or derivatives, added as heat stabilizers. Examples of such additives,
which are usually pr~,crielary to the supplier, are metal stearates, 2,6-
dimethylphenolic compounds, and thiodiesters of long-chain alcohols.
Polyolefins may also contain light stehili~ers, such as hindered amines,
benzotriazoles, and the like. All of the polyolefins used in the present
examples are thought to contain small amounts of these proprietary
st~hili~ers.
One way to specify the blend composition is that at least about
0.2% of the total formulation (polyolefin plus graft copolymer) should be
18
13400fi.~
chemically grafted acrylic polymer or copolymer within the molecular
weight limits specified. The l"axi",um amount is about 10% grafted
acrylic polymer, with up to about 5% g.~ll6d acrylic polymer being
preferred for cost opti"~ization and optimization of most properties of the
blend.
Optionally, the blend of concentrate and polyolefin may be further
I"Gdif;ed by the introduçtion of fillers, both inorganic and organic, fibers,
impact modifiers, colorants, stabilizers, flame retardants, and/or blowing
agents.
Blowing agents may be gases, such as nitrogen or carbon dioxide,
admixed with the polymer melt in the extruder and allowed to expand
upon extrusion. More often, blowing agents are solids which liberate
gases, usually nitrogen, at a specific melt temperature, and which are
mixed into the melt, or blended from a pre-compounded mixture of the
blowing agent dispersed in a polymeric matrix. The melt temperatures
for the polyoleffns are typically in the range of about 200 to about 230~C,
although other temperatures may be used, depending on the specific
blowing agent. Solid blowing agents include azo compounds such as
azodicarbonamides, azoisobutyronitrilss, hydroazo compounds, or
compounds containing the nitroso group.
The blend of the graft copolymer and polyolefin is useful in
thermoforming, film making (espe~"y blowing and extruding), blow
molding, fiber spinning, acid and basic dyeing, foaming, extrusion (sheet,
pipe, and profile), coextrusion (multilayer film, sheet, preforms, and
parisons, with or without the use of tie layers), hot melt adhesives,
calendering, and extrusion coating (for the preparation of polymer/fabric,
carpet, foil, and other multiiayer constructions). Such graft copoly-"era,
especi~lly with small amounts of copolymerized acid functionality, ars
useful when blended with polyolefins for improved printability. The grafts
19
13~0065
themselves may bs used as tis layers between otherwise incompatible
polymers.
In extrusion, the graft copolymer is useful, especially with LLDPE,
at reduction of melt fracture without an effect on the melt flow rate. Unlike
the additives of U.S. Patent No. 4,094,297, the present additives do not
plate out when the ,.,~;fie(l polyolefin is extruded for extended times.
When polypropylene is modified with the graft copolymers of the
present invention, it may be employed in the manufacture of many useful
objects, such as extrusion- or injection-blown bottles for packaging of
o food.stuffs, aqueous solutions such as intravenous feeds, hot-filled items
such as ketchup, or extruded articles in profile form such as clips,
scrapers, window and door casings and the like. The foamed articles
may be used as substitutes for wood in moldings, for packaging
materials, for insulation or sound-deadening materials, for food
containers, and other rigid-article applications. Films may be used in
many protective or wrapping applications, such as for food packaging,
blister packaging of consumer goods, and the like.
The graft copolymers of the present invention are useful in
preparing polyolefin fibers, espec~ y polypropylene fibers; they are
esreci~lly useful when the graft copolymer is formed from a
polypropylene trunk. Polypropylene is relatively easy to process into
fibers having high strength and toughness.
Polypropylene fibers show certain deficiencies which include
difficulty in dyeing and poor long-term dimensional stability. Grafts
containing functional sites capable of accepting dys may be prepared by
the present pr~cess~by inc~i~,orating low levels of dye-accepting
monomers, such as methacrylic acid, dimethylaminoethyl methacrylate,
N-vinylpyridine, and the like. The improved sag resistance noted for the
1~400Gi
present graft polymers in a polypropylene matrix should correspond to
improvements in creep resistance of the fiber.
Polypropylene may be formed into fibers by slitting tape from
extruded film to form large-denier, coarse fibers, by extruding
monotilaments into large~enier fibers with a controlled cross-sectional
size, or by extruding multifilaments through a spinnerette to produce
bundles of small-denier fibers. In all cases, the fibers may be draw-
textured. As an example, small-denier polypropylene fiber bundles may
be extruded from a 25.4-mm, single-screw extruder having a screw
o length-to-diamster ratio of 24:1, such as that supplied by Killion
Extruders Corp. of Cedar Grove, New Jersey and equipped with a static
mixer, metering pump and spinnerette assembly with multiple orifices.
Using such equipment the extruded polypropylene would be passed
thought a cooling bath and then over a ssries of godets (metal rolls with
heating or coolTng capability) to orient the polymer or quench existing
orientation.
Polypropylene fibers may be used for, among other things,
strapping, netting (including fish nets), slit tape, rope, twine, bags, carpet
backing, foamed ribbon, upholstery, rugs, pond liners, awnings,
swimming-pool covers, tarpaulins, lawn-furniture webbing, shades,
bristles, sutures, cigarette filters, nonwoven fabrics, such as for tea bags,
bed sheets, bandages, diaper liners and the Iike, and for doll hair,
apparel and tho like.
The graft copolymer of the present invention may also be used to
improve the compatibility of polymers in blends whsre they would
othen~ise be poorly compatible. The graft copolymer is incorporated into
such blends, pr~for~bly at levels of from about 0.2 to about 10 %,
prefer~bly from about 0.5 to about 5%, and more preferably from about
0.8 to about 2.5%, to achieve the desired improvement in compatibility.
Higher levels of the graft copolymer may be used, but increases above
1340~6;
the preferred level generally show only small improvements in
co",pa~ibility.
As noted above, compatibility is not easily predicted. As a general
rule non-polar polymers are poorly compatible with more polar polymers,
but poorly comp~tible blends may also be found experimentally among
polar~polar or non-polar-non-polar blends. Examples of the non-polar
polymers are olefinic polymers such as high- and low-density
polyethylene and linear low-density polyethylene, polypropylene
including atactic polypropylene, poly-1-butene, poly-iso-butylene,
o ethylene-propylene rubber, ethylene-acrylic acid copolymer, ethylene-
propylene-diene terpolymer rubber, ethylene-vinyl acetate copolymer,
poly (ethylene-propylene), polymethylpentenes, and ionomers such as
polymers of ethylene with metal-salt-neutralized acrylic acid.
Relatively more polar polymers, called polar polymers for the
purposes of this d;~clQsure, include acrylonitrile-butadiene-styrene
polymer, acetal polymers, polyarylates, acrylic-styrene copolymers,
acrylonitrile-styrene-acrylic polymers, acrylonitrile-styrene polymers
modified with ethylene-propylene rubber, cellulosics, polyester-polyether
block copolymers, polyesters such as polybutylene terephthalate and
!O polyethylene tarephtl,alate, and including liquid-crystal polyesters,
polyetheramides, polyetheretherketones, polyetherimides,
polyethersulfones, ethylene-vinyl alcohol copolymers, polyvinyl chloride,
chlorinated polyvinyl chloride, polyvinylidene chloride and fluoride,
styrene polymers such as polystyrene, high-impact polystyrene, styr~ne-
acrylonitrile copolymers, styrene-butadiene copolymers, styrene-maleic
anhydride copolymers, alkyl-substituted styrenes copolymerized with
styrene alone or with the additional monomers !isted for styrene,
polyphenylene ether, polyphenylene sulfide, polysulfone, polyurethane,
polyamides, i.e., nylons sueh as nylon 6, nylon 6-6, nylon 6-9, nylon 6-10,
o nylon 6-12, nylon 11, nylon 12, amorphous nylons, polyamideimide,
l~lq~65
polycaprolactone, polyglutarimide, poly(methyl methacrylate), other C~ to
C8 poly(alkyl (meth)acrylates) and polycarbonates. The acrylic polymers
refer.~d to above are polymers containing at least 50 weight percent, and
prefer~~bly at least 80 weight percent, of mers of acrylic acid and/or
methacrylic acid (referred to collectively as (meth)acrylic acid) or their
esters, preferably their alkyl esters and more preferably their alkyl esters
in which the alkyl ~roup contains from one to eight, preferably one to four,
carbon atoms. The remaining mers are those from one or more
monomers copolymerizabl~ with the (meth)acrylic acid or ester by free-
o radical polymerization, preferably vinylaromatic monomers, vinyl esters
or vinyl nitriles, and more preferably mers of styrene or acrylonitrile.
In the examples which follow, polymer concentrates and polymer
blends were tested using standard procedures which are summarized
below.
Unreacted monomer in the reaction mixture prior to solvent
removal or subsequent to extruder devolatilization was determined using
a gas chromatographic technique.
The coll3cted volatiles were analyzed by gas chromatography on
a 25 meter CP wax 57 CB wall coated open tubular fused silica column
at 40~C. A co-"p~iison of the major signals for the solvent with the MMA
signal was used to ~Jeter",ine the amount of residual monomer in the
reactor and ll,GrG~ore give a measure of conversion immediately. A more
accurate measure of conversion was obtained by a C,H,O analysis of the
graft copolymer. The carbon content was used to calculate EPDM or
polypropylene content by interpolating between the carbon content of
EPDM (85.49%) or ~olypropylene (85.87%) and acrylic polymer (60.6%).
The graft copolymers are analyzed by solvent extraction to remove
the ungrafted (meth)acrylic portion, whose molecular weight is then
determined by gel permeation chromatographic techniques. A technique
1~40~6~
for separatin~ the ~raft copolymer from ungrafted polyolefin is not
available. Forconce.lt~t~s, 0.8-1.3 9 of polymerwas placed in a
centrifu~e tube with 17 crn3 of xylene. The tube was shaken overni~ht.
Then the tube was placed in an oil bath set at 138~C. The tubes were
periodically taken from th~ bath and shaken until all polymer had
dissol~od. The fact that all dissolved ind~ es that no crosslinhng
occurred. Th~ tubes wer~ cooled durir~ which time the polyprowlene
- co-,tainin~ subst~nces pr~pit~le. Then the tubes were centrifuged at
15 000 rpm for 2 hours and the xylene solution was removed with care
not to remove any floats. The molecular wei~ht of the acrylic polymer
extracted by the xylens was determined by gel per-"e~tion
chromalo~r.lph~r. The pr.~cedure was rsFs~ted on the resulting plug to
extract ~IdiliG,~al (meth)a¢rylate. The value l~helled % graft is the
pGItion of the (meth)acryli¢ polymer fo,l"eJ which remains with the
polyolefin plug after repeated exl,~.tion. The co",posilion is determined
from the carbon analysis of this plug.
- The polypropylene concentrate and any additives were blended in
the melt on a 7.6 cm by 17.8 cm electric mill with a minimum ~ap of 3.8
mm set at 1 90~C. Once the material had tluxed, it was mixed an
~dditional 3 minutes. Higher temperatures wer~ used for hi~her viscosity
materials (for example, mfr-0.5-2 material was done at 195-21 0~C).
While still hot, the material was either co"~ression molded or cut into
small chunks (about 1-2 cm in each dimension) for ~ranulation (5 mm
screen). It is of inler~st that the additives of the present inventiGn
cont,ibute to easy release from hot metal surfaces such as mill rolls
~Haake Rheocordlbowls etc.
Millin~ of poly~thylene was done in a similar manner except that
the HDPE blends were milled at 200~C and the LLDPE blends were
milled at 170~C.
24
* Trademark
~ .
134006a
A 2.5 cm~Killionnextruder was used for extrusion blending. A two
stage screw was used at 150 rpm, with all three zones set for 190~C. The
on~strand die was also set at the same temperature. A vacuum vent
was used. The strand wal; cooW in water and pelletized. The extrusion
rate was 4.5 ko per hour.
Melt bbnding in a''Haake Rhsocord'~a batch melt mixer) was done
on 50 9 sampbs at 1 90~C or at 21 0~C and 100 rpm in air. Mixing was
continued for three minutes after peak torque was reached. Sample size
was 50 ~rams.
, 10 The po~olefin blends were compression molded in an electrically
heated carverSress 15 x 15 cm or"Farrel'press 30.5 x 30.5 cm. The
samples were moWed between aluminum plates with an appropriate
spacer to provide the req~red thickness 0.25-3.8 mm. In one method the
hot melt was taken directly from the mill roll and placed between two
aluminum sheets. This was then placed in the press set at 1 90~C and
presse.J at high pressure ~68-91 metric tonnes for the Farrel press and
6820 kg for th~"Carver'pre6s). Aner three minutes the mold was placed
in an unheated press at high pressure for three minutes. In the other
procedure, ~ranulated material or pellets produced from an extrusion,
Haake, or milling operation were dried and then compression molded.
The pruc~Jure used was the same as for molding a melt except that a 5
minute preheat was used while ."aintaining a slight pressure on the
press. This was tolbwed by the high pressure molding in the hot and
cold presses. A hot press of 1 90~C was usually sufficient for mfr~4
-25 polypropylenes, but higher viscosity polypr~p~lenes would split during
sag testing unlsss higher molding temperatures were used (195-210~C).
Polyetl,~l~ne was molded in a similar manner except that HDPE
was molded at 170~C and LLDPE at 150~C.
* Trad~ark (each instance)
.
~.''';
1~4006.~
Injection molding of polypl.JpylGne was perform~d on i Newbury *
injection moldin~ machin~ in an AST~I tamily moW. Material to be
moWed was dried for 16 hours at 60~C. The first barrel zone was set for
204~C, and the other two barrel zones and the noz71e were set hr 21 8~C.
The ram time was set for 3 seconds and the cycle of 15 secGnds for
injection and 45 seconds overall was used. The injection pressure was
2100 kPa and the back pressure was 690 kPa. The screw speed was
100 rpm. Both mold platens were sst tor 60~C.
The sag tests are pe.~r",6-1 on a co",pr~ssion molded sheet 10 x
o 10 x 0.15 cm. This sheet was clamped in a frame with a 7.6-cm-square
opening. There were metal rulers attached to the front and back of the
frame for use in measuring sag. The frame and sheet were placed in a
hot, forced air oven (typically at 190~C). The amount of sag of the centsr
of the sheet was then r~ Jed as a function of time. Typically, the sag
was first recorded at 2.5 cm but for slow saggin~ materials sa~s as low as
16 mm were r~cor.leJ. Data was recoh~e~l up to 10.2 cm of sag or for 30
minutes, whichever occurred first.
The term ~slope~ refers to the slope of a plot of the natural
logarithm of the sa~ in ce"ti",eler:, vsrsus time, resultin~ in 8 straight line.A hi~h slope indicates that the materisl sags quickly while a low slope
indicates that it sa~s sbwly. The advantage of comparing slopss in this
manner is that it eliminate~ any differences in oven cooling when the
sample is introdvce~ (due to differ~nces in ths time the oven is open,
room temperatures, etc.).
Crude thermoforming was done in ths laboratory to illustrate this
melt stren~th effect. A sh~et of polypropybne or modified polypropylene
was heated in a forcéd air oven at 190~C, removed from the oven, placed
over a female mold, and subjected to vacuum.
* TrA~ TLA rk
.~.,
1~4006~
The capillary flow data were measured on a Sieglaff McKelvey
rheo"~GtGr. Ths flows were recorded at ten shear rates (1 to 100-
redpr~al secondj) at each te~ er~t~Jre. The data was fit to the power
bw, i.e., visoosi~y~k(temp~rature)~(shear rate)~, and the values at 1 and
1000 redprocal secor,~ls were calculated from this best fit e~luAtion. The
parallel plate vi~sity ref~rs to measurements on the'~heometrics"*
Dynamic Spe~o"-eter, ~rcJed at a strain of 5%.
Differential scanning calorimeter (DSC) measurements of melting
and nucleation were pe~r"-~ on a duPont instrument. A value of 59
caUg was used for the heat of cryst~ tion and psr cent crystallinity was
corr~t~ for the presence of the melt additive. The nuc'e-~ion
temperature was measured in an experiment in which the polypropylene
was melted at 200~C for 2 minutes and then cooled at 1 0~C/min. The
temperature at which peak crys'~ -~on occurred is called the
nudeation temperature. The isothermal crystel';~tion time was recorded
by cooling the molten pol$~n~pylene quickly to 127~C and the exotherm
recorded with time.
The physical properties of the polypropylene homopolymer and
~medium i."pa~t' copolymsr are determined on extruded and injection
moWed sampbs, although similar results have been observed in milled
and compression molded samples. In cenain examples below are
described spe~ ed oqulpment for preparing foamed sheet, rod or
proffle, extruded rod or tubing, fibers, cast film, mono~Yi~lly o,iented and
biaxially orientod film, and injection blow-molded bottles or hollow
'2~ containers.
The examples are intended to illustrate the present invention and
not to limit it except as it is limited by the claims. All percentages are by
wei~ht unless o~l,elwise specifieJ and all r~ag6nts are of good
commerdal quality unless otherwise specified.
27
* Trader[ ark
~'.
. .
13~006.;
FXAMPI F 1
This example illu~tr~tes prepar~tion of a Graft Copolymer (GCP) of
Po'y~ro~"rlene (PP) Methyl Methacrylate (MMA) and Ethyl Acrylate (EA).
A polypropylene-acrylic ~ran copolymer is made by polymerizing a
5% ethyl acrylate (EA) - 9S% methyl methacrylate (MMA) n,GnG",er
mixture in the presence of polypropyl~ne (wei~ht ratio of
poly~r~pylene:monomer . 0.67:1). Radicals ar0 generated from di-
tertiary-butyl pdn~xwe (DTBPO) at the rate of 0.00010 moles per liter per
' minute (radical flux). Monomer and initiator are fed over 60 minutes and
the theoretical (100% conversion) solids at the end of the reaction is
55%.
A 6.6 liter reactor e~uipped with a double heJical agitator (115
rpm) was char~ed with 1780 9 of an inert hydrocarbon solvent mixture of
2-methylalkanes havin~ 6-12 C-atoms and 880 9 polypropylene (mfr~4)
and hsated to 1 75~C. After 2 hours the temperature was J~c~eased to
1 55~C and the batch was stirred for 1 additional hour. Over a two minute
- period two solutions were aWed. The first consi! le~l of t.04 9 of di-t-
butyl peroxide in 21 9 of the hydrocarbon solvent. The second consisted
of 0.06 ~ ot di-t-butyl peroxide in 2.1 9 of ethyl acr~rlate and 42 ~ of methyl
methacrylate. For the next 58 minutes at the same feed rate a feed of
1.87 9 of di-t-butyl peroxid~ and 62 g of ethyl acrylate in 1215 ~ of methyl
methacrylate was added at the same feed rate as the second fQed. This
feed schedule results in a radical flux of 0.00010 durin~ the feed tirne.
After the feed was complete the rtldcliG.) was held at 1 55~C for an
additional 15 minutes. Then it was devol~b';~s~ by passing through a 30-
mm"Werner rf~iderer'l3xtruder wTth two vacuum vents at 200-250~C.
The concantldt~ product (¢oncentrate) is a mixture wherein the elemental
analysis showed that the con,posTlion is 56% (meth)acrylate. Extraetivs
results showed 15.9% of the poly."erTzed (meth)acrylic monomers were
~rd~l~l, and the Mw of the Imeth)acrylic polymer was 91 S00. The
28
* Trade Telrk
1~006~
concentrate may be blended with other thermoplastic polymers such as
polypropylene.
The following Table shows the efficiency of the above concentrate
blended at different levels in improving sag rssistance of a polypropylene
homopolymer having a melt flow rate (mfr=4) of four.
T~RI F I
Wt. % of sag sample sag at
concentrate slope, thickness 17 min timeto
in blend ,min-~ ( mm) (cm) sa~ ~.5cm
0 0 0.18 1.75 2.29 39 min
1 .5 0.12 1 .45 6.1 0 6.0
2.5 0.1 2 1 .70 4.57 6.8
3.3 0.06 1.78 3.05 11.4
5.0 0.045 1.73 1.27 13.1
7.5 0.030 1.75 1.02 ----
FXAMPI FS ~ - 51
A polypropylene-acrylic graft copolymer is made by polymerizing a
5% ethyl acrylate (EA) - 95% methyl methacrylate (MMA) monomer
mixture in the presence of polypropylene (weight ratio of
polypropylene:monom0r . 0.67:1). Radicals were generated from
di-tertiary-butyl peroxide (DTBPO) at the rate of 0.00010 moles per liter
per minute (radical flux). Monomer and initiator were fed over 60
minutes and the theoretical (100% conversion) solids at the end of the
reaction was 52.5%.
A 6.6 liter reactor e~ pped with a pitched-blade turbine agitator
(375 rpm) was charged with 1880 9 hydrocarbon solvent and 840 9
134~06~
polypropylene and heated to 1 55~C. The mixture was stirred for 3
hours. Over a two minlne period two solutions were ~dded The flrst
consisted of 1.06 ~ of di-t-butyl pero~tide In 21 9 of hyJ,~carbon solvent,
as in Exampb 1. The second co,)si~ted of 0.06 ~ of di-t-butyl peroxide
in 2.1 9 of ethyl acrylate and 40 ~ of methyl methacrylate. For the next
58 minutes a feed of 1.8J 9 of di-t-butyl peroxide and 61 9 of ethyl
acrylate in 1157 9 of methyl i"etl-a~late was added at the same feed
rate as the second feed. This feed schedule should produce a radical
flux of 0.00010 during th~ feed time. Afterthe feed was complete, the
reaction was held at 1704C for an ~Jitional 15 minutes. Then it was
devolatilized by passing through a 30-mm'~Hernsr-Pfleiderel"extruder
with vacuum vents at 200-250~C. The concentrate showad that the
cGmpo6ition is 51% acryJate.
A~hJ)t;s~al polypropylene-acrylic ~raft copolymers (Examples 2-
51 ) were prepared by th~ procedure of this Example and ev~4J~ted as
3.5% blends in polypropylene (mfr=4) as melt strength additives. The
following TabJe illu~l.ala~ the polym~fization con-litions for the
concentrate and the percent acrylic polymer pr~50nl in the concentrate
with the sag r~sTst~nce of the bbnd with the polypropylene.
In the f~llowin~ Table ll, DTBPO is di(t-butyl)peroxide, TBPB is t-
butyl perbenzoate, and DDBH is 2,5-dim~thyl-2,5-di(t-
butylperoxy)hexane .
* Trademark
.,,
, ~,
., . .. , . " . , , , , ~ , .. . . . .. .
13~006a
T~RI F ll
sa~ % fecd rad- %EA
slope acrylic init- solids polymer time, ical in
E2~ min-~ in conc j~Q~ % temp.~C min flux
Con~ 0.15-0.18 -- ---- ----- ------ --- ---- ---
0.03-0.05 56 DTBPO 55 155 60 0.00010 5
2 0.06 51 DTBPO 52.5 155 60 0.00010 5
3 0.06 52 DTBPO 55 155 60 0.00010 5
4 0.045 55 DTBPO 55 150 60 0.00010 5
0.08 57 DTBPO 55 145 60 0.00010 5
6 0.05 57 DTBPO 57 150 60 0.00010 5
7 0.10 49 DTBPO 55 150 60 0.00007 5
8 0.06 53 DTBPO 55 150 60 0.00015 5
9 0.06 55 DTBPO 55 150 60 0.00010 10
0.11 53 DTBPO 55 150 60 0.00010 0
11 0.056 48 DTBPO 55 155 60 0.00010 10
12 0.07 51 DTBPO 50 150 60 0.00010 5
13 0.11 58 DTBPO 55 145 120 0.00007 5
14 0.10 57 TBPB 55 145 120 0.00007 5
0.09 56 TBPB 55 150 120 0.00010 5
16 0.12 54 TBPB 55 150 120 0.00007 5
17 0.13 55 TBPB 55 150 120 0.00015 5
18 0.06 55 DTBPO 55 150 120 0.00007 5
19 0.06 49 TBPB 55 150 60 0.00010 5
0.10 51 TBPB 55 150 120 0.00010 5
21 0.14 57 TBPB 56 150 120 0.00010 5
22 0.13 51 TBPB 55 150 60 0.00010 5
23 0.15 55 TBPB 55 150 120 0.00010 0
24 0.15 56 DDBH 55 150 120 0.00010 5
O fi i
TARI F ll (~ontinlled)
sag % feed rad- %EA
slope acrylic init- solids polymer time, ical in
in conc j~Q~ % temp.~C min
0.14 57 TBPB 55 150 120 0.00015 5
26 0.09 51 TBPB 55 150 60 0.00010 5
27 0.15 54 DDBH 55 150 120 0.00010 0
28 0.11 51 DDBH 55 155 120 0.00010 5
29 0.10 53 DTBPO 50 150 120 0.00007 5
0.10 54 DTBPO 50 150 120 0.00005 5
31 0.15 53 DTBPO 50 150 120 0.00005 5
32 0.10 51 DTBPO 55 150 120 0.00007 5
33 0.12 55 TBPB 55 1 50 120 0.00007 5
34 0.18 55 DDBH 55 150 120 0.00007 5
0.07 53 DTBPO 55 150 120 0.00005 5
36 0.09 51 DTBPO 55 150 120 0.00010 5
37 0.14 51 TBPB 55 1 50 120 0.00005 5
38 0.10 37 DTBPO 55 155 60 0.00010 5
39 0.11 - 43 DTBPO 55 155 120 0.00007 5
0.08 48 DTBPO 55 155 120 0.00005 5
41 0.10 47 DTBPO 55 155 120 0.00007 5
42 0.07 48 DTBPO 55 155 60 0.00010 5
43 0.10 43 DTBPO 55 155 120 0.00005 5
44 0.10 50 DTBPO 55 155 120 0.00007 5
0.10 54 DTBPO 55 150 120 0.00010 5
46 0.10 54 DTBPO 55 150 1 20 0.00007 5
47 0.07 54 DTBPO 55 150 120 0.00005 5
48 0.08 56 DTBP055 150 120 0.00007 5
49 0.08 55 DTBPO 55 145 120 0.00007 5
T~RI F ll (contin~led)
32
.. . . "., . , ~ ~ , . . .. ..
134006~
sag % feed rad- %EA
slope acrylic init- solids polymer time ical in
~x. ~Q-1 in conc j~Q~ % temp.~C min
0.09 56 DTBPO 55 145 120 0.00005 5
51 0.08 55 DTBPO 55 145 120 0.00010 5
Control = PP with no concentrate
The calculated percent of grafted acrylic polymer and the
mlo'ecul~r weight (Mw) of ungrafted acrylic material are tabulatsd below
in Table lll on certain samples where the ungrafted acrylic polymer was
separated from the concenllate by extraction.
TABI F 111
% Acrylic Polymer
Fx~m~le (~r~fted to PP ~
2 12.3 107,000
10.6 119,000
11 29.8 71,800
14.8 43.000
46 10.7 62,600
47 21.7 87,300
Note: (Mw = weight average molecular weight)
FXAMPI F !'i:~ - 54
This example shows a larger scale preparation of a polypropylene-
acrylic graft copolymer made by polymerizing a 5% ethyl acrylate (EA) - 95%
methyl ~"~tl,ac"rlate (MMA) monomer mixture in the presence of polypropylene
(weight ratio of polypropylene:monomer= 0.67:1). R~di~lC were generated
0 6 a
from di-tertiary-butyl peroxide (DTBPO) at the rate of 0.000065 moles per liter
per minute (radical flux). Monomer and initiator were fed over 122 minutes and
the theoretical (100% conversion) solids at the end of the reaction was 47%.
A 380 liter reactor e~luipped with a back-slope turbine agitator was
charged with 102.3 kg of the hydrocarbon solvent and 36.4 kg of mfr=4
polypropylene homopolymer and heated to 150~C over 4 hours. Two solutions
were added over a twenty minute pefiod. The first consisted of 82 9 of di-tertiary-
butyl peroxide in 826 g of the hydrocarbon solvent. The second consisle-l of
454 9 of EA and 8.6 kg of MMA. Addition of the first solution was then continuedo at a lower rate to feed an additional 82 g of di-tertiary-butyl peroxide and 826 g
of the hydrocarbon solvent over 90 minutes. At the same time the monomer
~ddition of 2.3 kg of EA and 47.5 kg of MMA was continued over 102 minutes
- (ending 12 minutes after the initiator feed had finished). The reaction was held
at 150~C for an additional 15 minutes. Then an additional 23 kg of hydrocarbon
solvent was pumped in over 30 minutes. The reaction mixture was then
devolatilized by passing through a 20-mm Welding Engineers twin-screw
extruder at 200 rpm and 200-250~C over 14 hours. This concentrate is Ex. 52.
Similar preparations labelled 53 and 54 were synthesized with changes in feed
time and radical flux as indicated. The following Table IV shows the
improvement in sag resistance when concentrates of Example 52, 53 and 54
are blended with polypropylene of mfr=4:
34
~ ., . . , , , . . ,~
13~006~
T~RI F IV
% Weight
Conc Sag Fraction
in Slope Acrylic Init- Polymer Feed Rad.
E~, Blend min-~ in conc. ~QC Solids ~ Time
Con. none 0.19 ---
52 2.5 0.11 0.6 DTBPO 47 150 122 0.000065
3.5 0.10
53 3.5 0. 11 0.6 DTBPO 45 150 90 0.00007
5.0 0.10
54 3.5 0.15 0.6 DTBPO 49 1 50 78 0.00008
5.0 0.09
FXAMPI F 55
This example and Table V demonstrate the unsxpected
advantage of the concentrate of Example 4 in the improvement of sag
resistance for both high density polyethylene (HDPE) and linear low
density polyethylene (LLDPE). Data for HDPE are for polymers of two
different mfr values (4 and 8) and are obtained at 1 50~C, The LLDPE
values are on a single resin having a density of 0.917 g/cc, but at two
differenttemperatures. Comparison molded polyethylene samples
prepared for this test had a significant increase in gloss over the
unmodified control.
l t~ fi ~i
TARI F V
Time to ~. Minutes
Pob/~hyleneWt-%~itive Tem~~t' 508 mm 7R:) mm
HDPE mfr=8 0 150 8.7 9.3
2 102 11 9
3 5 15.8 30.0
31.4
HDPE mfr=4 0 150 8.0 9.0
3.5 10.5 12.0
26.0 --
LLDPE mfr=2 0 170 5.3 6.0
17.7 21.4
LLDPE mfr=2 0 180 4.6 5.2
8.5 10.0
~- FXAMPI F 56
A polyethylene-acrylic graft copolymer concentrate was
synthesi~ecl in a manner similar to that previously described for
polypropylene-acrylic graft copolymers. The polyethylene-acrylic graft
copolymer concentrate was made by polymerizing a 100% methyl
metl,ac~ylate (MMA) monomer mixture in the presence of polyethylene
(wei~ht ratio of polyatl,ylene:monomer= 0.5:1). Radicals were
generalecl from di-tertiary-butyl peroxide (DTBPO) at the rate of 0.00010
moles per liter per minute (radical flux). Monomer and initiator were fed
over 60 minutes a~d the theoretical (100% conversion) solids at the end
of the reaction was 55%.
A 6.6 liter reactor s~u;rped with a double helical agitator (115
rpm) was char~ed with 1760 9 hydrocarbon solvent and 725 9
1~4036~
polyethyl0ne (mfrs4, density=0.95) and heated to 1 50~C. The mixture
was stirred for 3 hours. Over a two minute period two solutions were
added. The first consist~ of 1.63 9 of di-t-butyl peroxide in 48 g of
methyl ~,.ethacrylate. For the next 58 minutes a feed of 1.73 9 of di-t-
butyl peroxide in 1401 9 of methyl methacrylate was added at the same
feed rate as the second feed. This feed schedule should produce a
radical flux of 0.00010 during the feed time. After the feed was
complete the reaction was held at 1 50~C for an additional 15 minutes.
Then it was devolatilized by passing through a 30-mm Werner-
Pfleiderer extruder with vacuum vents at 200-250~C, The elemental
analysis showed that the concentrate contained 64% (meth)acrylate.
FXAMPI F 57
This example shows that both polyethylene-acrylic graft polymer
and polypropylene-acrylic graft polymer concentrate were effective at
reducing the sag of HDPE. The blend of concentrate with HDPE mfr=4
and density=0.95 was milled at 220~C and the hot material from the mill
was molded at 21 0~C. Sags. were measured by the same procedure
used for polypropylene sheet except that an oven temperature of 1 50~C
was used.
TABI F Vl
Concentrate Sag Slope25.4 mm Sag 76.2 mm Sag
of FY~m~l~le %Conc. ~1 (min) (min)
Control none 0.57 7.4 9.4
56 5% 0.27 9.0 13.0
56 10% 0.11 10.0 19.8
4 5% <0.015 15.0 30 min to 31.7 mm
.. . ~ , ,~ . ,.
13~0Q65
FxAMpl F 58
This example shows that the polyethylene and polypropylene graft
copolymer concentrates are effective in improving sag resistance of
HDPE while ungrafted acrylic polymer of similar Mw is not. Addition of
as much as 5% of a comrnercial acrylic molding powder poly(methyl
methacrylate), Mw 105.000. designal~d ~A") showed no decrease in sag
rate while 3% poly(methyl ",etl,aclylate) present as the graft copolymer
concentrate resu!ted in large reductions of sag rate.
The specific concentrate used in part of this study was synthesized
O in the following manner. The polypropylene-acrylic graft copolymer was
made by polymerizing a 5% ethyl acrylate (EA) - 95% methyl
methacrylate (MMA) monomer mixture in the presence of polypropylene
of mfr=0.4 (weight ratio of polypropylene:monomer= 0.67:1). Radicals
were generated from di-tertiary-butyl peroxide (DTBPO) at the rate of
0.00007 moles per liter per minute (radical flux). Monomer and initiator
wsre fed over 120 minutes and the theoretical (100% conversion) solids
at the end of the reaction was 55%.
A 6.6 liter reactor equi~ped with a pitched-blade turbine agitator
(375 rpm) was charged with 1780 9 of the hydrocarbon solvent and
880 9 polypropylene (mfrØ4) and heated to 160~C. The mixture was
stirred for 2 hours and then the temperature was dec,~ased to 150~C for
one hour. Over a two minute period two solutions were added. The first
cGnsisled of 1.22 9 of di-t-butyl peroxide in 20 9 of the hydloc~r~on
solvent. The second consisted of 0.0002 mg of monomethyl ether of
hydroquinone (MEHQ) and 0.05 9 of di-t-butyl peroxide in 1.1 9 of ethyl
acrylate and 21 9 of methyl methacrylate. For the next 1 18 minutes a
feed of 13 mg MEHQ and 2.70 9 of di-t-butyl peroxide in 66 9 of ethyl
acrylate and 1253 9 of methyl methacrylate was added at the same feed
38
9~S
rate as the second feed. This feed schedule should produce a radical
flux of 0.00007 durin~ the feed time. After the feed was complete the
reaction was held at 150~C for an a.lditional 15 minutes. Then it was
devol~ e.J by passing through a 30 mm Werner-Pfleiderer extruder
with two vacuum vents at 200-250~C. The elemental analysis showed
that the con~snll~le cont~;ned 53% (meth)acrylate.
The blends of HDPE (mfr=7, densityØ95) and graft copolymer
concentrate was milled at 200~C and the hot materials were formed into
sheets from the mill at 170~C. Sags were measured by the same
o ploceJure used for polypropylene sheet except that an oven
temperature of 150~C was used.
T~RI F Vll
Concentrate Sag Slope25.4mm 50.8 mm
Fx~ ple I Qvel ~i~1 ~ ~rnin) ~ (mirl)
Control none 0.59 7.4 8.7
A 3.0% 0.58 7.1 8.3
A 5.0% 0.54 7.6 9.0
56 5.0% 0.27 -- 10.3
4 2.0% 0.28 8.2 10.2
4 3.5% 0.056 9.4 15.8
4 5.0% 0.038 10.4 31.4
58 3.5% 0.37 7.4 9.2
58 5.0% 0.30 8.1 10.0
39
1~036~
FXAMpl F 59
The concentlate of Example 4 was blended with LLDPE and the
results of evaluating the sa~ resistance improvements are shown below
in Table Vlll. The blend of modifier and LLDPE was milled at 1 70~C and
the hot material from the mill was milled at 150~C. Sag resistance was
measured by the same pr~c~ure used for polypropylene sheet at the
temperature listed.
~A~ is an LLDPE havin~ an mfr=2.3 and a density of 0.92,
recG"""ended for casting and extnuding applications.
~B~ is an LLDPE having an mfr=1 and a density of 0.92,
recGn,i"ended for blow molding and extrusion applications.
T,ARI F Vlll
Sag Sag Slope25.4mm 101.6 mm
I l npF Concentr~te Temp. mirt1_ sag (min) sa~ (min)
A none 1 80~C 0.58 3.4 5.6
A 5% Ex. 4 180~C 0.24 5.2 10.6
A none 1 70~C 0.54 3.9 6.4
A 5% Ex. 4 1 70~C 0.096 9.5 23.0
B none 1 50~C --- 7.8 15.6
B 5%Ex.4 150~C --- 33.7minat19mm
FXAMPl F 60
This example iilustrates improved sa~ mG.lilic~tion and increased
nuc's~tion temperature for polybutylene, when blended with the
concentrate. Polybutylene, injection grade, mfrs4, with and without 2.44
wt. % of the concentrate of Example 20 were milled at 1 90~C and
13~00fit~
pressed into pl~ques of about 1.7 mm thickness. Times were measured
for various distances of sag at 1 45~C. DSC curves were used
(heaVcool time = 20~C/min). A higher crystallization temperature relates
to increased speed of nu~'3~tion and solidification of the heated
polymer.
T~RI F IX
Weight
Percent Time to .cag (rnin:cQ~) n.~c Te~rAtllre. oc
Concentr~te ~5.4 mm 50.8 mm 101.6 mm ~ Crystallize
Control (0) 5:20 7:50 10:23 128 45
2.44 wt % 7:24 15:53 ~30 129 55
FXAMPI F 61
This ex&.--ple describes the preparation of a concentrate of
polypropylen~acrylic graft copolymer made by polymerizing 5% ethyl
! 5 acrylate (EA) - 95% methyl ~-,elhaclylate (MMA) monomer mixture in the
presence of an equal amount of polypropylene. R~dic~ls were
96ner~dled from di-tertiary-butyl peroxide (DTBPO) at the rate of 0.00017
moles per liter per minute (radical flux). Monomer and initiator were fed
over 30 minutes and the l~)eoretical (100% conversion) solids at the end
of the reaction was 50%.
A 6.6 liter reactor equipped with a double helical agitator (115
rpm) was charged with 1980 9 of the hydrocarbon solvent and heated to
1 70~C. 1000 9 of polypropylene (mfr.5) was fed to the reactor via a
melt extruder set a~ 200~C at a rate of about 10 9 per minute. After 45
minutes hold at 1 70~C the addition of monomer and initiator solutions
was begun. Over a two minute period two solutions were added. The
first consisted of 0.44 9 of di-t-butyl peroxide in 21 9 of the hydrocarbon
41
13~J6.~
sol~rent. The second consisted of 0.11 9 of di-t-butyl peroxide in 1.3 9 of
ethyl acrylate and 65 9 of methyl mell,acr~lale. For the next 28 minutes
a feed of 1.59 9 of di-t-butyl peroxide and 19 9 of ethyl acrylate in 914 9
of methyl methacrylate was added at the same feed rate as the second
feed. This feed schedule should produce a radical flux of 0.00017
during the feed. After the feed was complete the reaction was held at
170~C for an additional 15 minutes. Then it was devolatilized by
passing throu~h a 3~mm Wemer Plleider~r extruder with vacuum
vents at 200-250~C. The elemental analysis (carbon content) showed
o that the con~snl-~te contained 35% (meth)acrylate.
A sheet of polypropylene (mfr=4) with and without the concentrate
of this example was heated in a forced air oven to 1 90~C, removed from
the oven and immediately placed over a female mold and subjected to
vacuum. The top and bottom comer measurements were the average
of the 8 measurements in mm at the corner of each of the four side faces
of the box. The top and bottom center measurements were the average
of the 4 measurements in mm at the center of the edge of the 4 faces of
the box. These measurements are summarized in Table X and
demonstrate smaller wall thickness va-iations when the concentrate is
present.
TARI F X
WAI I THI~,KNF~ VARIATION IN THFRM~-F~RMFn PARTS
Top Top Bottom Bottom
Poly~ro~ylene Center Corner Center Corner
unmodified 1.14mm 0.88 mm 0.75 mm 0.025 mm
5% Ex. 61 0.97 mm 0.97 mm 0.35 mm 0.21 mm
42
13~0q~;
FXAMPl F f;~
This example demor,slraled the ur.~xpected higher nucleation
te..,pcr~ture anJ shorter time for crystallization imparted by addition of
the polymeric concentrate of Examples 1 and 52 to polypr~pylene of
mfr.4. The nucleation te-"par~tLJre was measured while cooling at
10~Clmin the melting te.~,perdture was measured while h eating at
20~C/min and the crystaHization time was measured isothermally at
127~C or 1 30~C. The extent of crystallization was reported for both
cooling and melting measu~ei"ents. Comparison was made with
o un~rd~ PMMA of similar Mw.
TA~I F Xl
Temp. of crystallization (~C) 127 127 130 130 130 130 130
Percent Concentrate 0 5 0 1.1 2.2 3.9 7.8
PolymerConcentrate of Example - 52 - 52 52 PMMAPMMA
Crystallization Time, min. 16.3 3.6 24.5 3.7 3.0 8.1 10.6
Nucl~- ~io.)Temperature,~C 105 112 107 118 118 112 110
% Crystallinity 39 40 41 46 42 42 41
Melting Temperature, ~C 165 166 169 170 168 170 168
% C~ystallinity 41 44 44 44 46 46 44
FXAMpl F 63
This example del"Gnsll~ted the lower equilibrium torque and
improven,onl in time to flux for blend~ of the concenl-dte of Example 1
with polypropylene of mfr.4 usin~ the Haake Rhaocord'*The test
conditions are ~JesclibeJ above. Peak torque at flux was also re~uce~
43
TrAtl~lArk
0~5
T~Rl F Xll
Wt.-%
Concentrate in Time to flux Equilibrium Torque
poly~ro~ylene (seconds) ~meter~r~rns ~t 21 5c
0 109 695
3 50 690
670
FXAMpl F 64
This example shows that a propylene-acrylic graft copolymer
concentrate may be used to improve the sag resistance of an acrylic
o sheet. About 20 parts of the graft polymer of Example 1 was milled with
100 parts of a commercial acrylic molding pow1er of Mw 105,000 and
co"~plession moWed. Sag tests indic~te~ that the sheet containing the
concenl,ate may be heated to about 5-1 0~C higher before flow
equivalent to that of the unmodified sheet was observed.
FxAMpl FS 65 - 66
Graft copolymer concentrates were prepared according to the
process deso-ilJ~ in Exarnples 52-54, using the conditions shown in
Table Xlll.
44
l?~ lOnfi5
T~RI F Xlll
Monomer Feed
Concentrate % Acrylic Init- Time Radical
of FY:3~ In t',onc. jj~Q~ SolidsTem~. ~C (min) _EI~
A 55 DTBPO 50% 150 120 0.00010
B 55 DTBPO 50% 150 120 0.00007
Concentrates A and B were blended together at a weight ratio of
2.8:1 to form concentrate C. As indicated in Table XIV, concentrate C
was blended at the 4% level with polypropylene and the indicated
amounts of di-t-dodecyl disulfide (DTDDS) and extruded. The sag
results for these blends are given in Table XIV below.
TARI F XIV
FY~rn~le % Concentr~te DTnDS Sa~ Slope in min-~
4 none 0.07
66 4 0.03% 0.05
67 4 0.3% 0.03
Stabilizing the conconl-dle during processing, as by using the
DTDDS, is seen to produce even more sig,)iticant improvement in melt
slr~n~h.
FXAMPI F 67
This example further demonstrates that the graft copolymer has
little effect on the high-shear viscosily but a pronounced effect on low-
shear viscosil~ in polypropylene.
134006~
The graft copolymer of Example 1 was admixed at the five
weight-percent level with an injection-molding grade of propylene
homopolymer, mfr=4, as in Example 63. ~api~l~ry and parallel-plate
viscosities were measured at various temperatures under conditions
.Jescribed above, under both low and high shear conditions. The results
shown in Table XV below demon~,ate the incr~ase in low shear
viscosity, especially at temperatures below about 210 ~C, with
essentially no effect on viscosity at high shear rate.
T~RI F XV
Conditions: I nW She~r Hi~h She~r
Amount of Graft Polymer: O % 5 % O % 5%
Test Te~er~tllre
C~pill ry Viscosity (a) 180 ~C 94000 133000 1900 2000
C~rill''ry Viscosity (a) 190 ~C 80000 110000 1900 1600
Capillary Viscosity (a) 210 ~C 57000 75000 1200 1100
Parallel Plate Viscosity(b) 190 ~C 630dO 99000 2100 2100
Parallel Plate Viscosity (b) 210 ~C 54000 58000 1800 1800
Parallel Plate Viscosity (b) 230 ~C 37000 39000 1500 1400
Shear Conditions:
a: Low Shear=1.0 sec-~; high shear= 1000 sec-~
b: Low Shear=0.1 sec-~; high shear= 500 sec-1
FXAMPI F 68
This exa."ple shows improved stabili~alion to weight loss on
heating by use of a disulfide or a substituted tri~ine stabilizer. A
polypropylene-acrylic graft copolymer similar to that of Example 4 was
blended with stabilizers on the mill roll. The graft copolymer (98 grams)
46
1340D~S
was fluxed on the mill at 1 95~C. The sl~bil;~er (2 ~rams) was added
and blended in tor 2 minutes. The ~~le~ial was removed from the mill,
cut into chunks, and granul~ed One or more of these stabilized
versions were then let down in a similar manner in additional ~raft
copolymer to produce ~raft copolymer stabilized at the 100-5000 ppm
level. The results on the TGA of s~bi~ tiol) are shown in the table.
Weight loss (%) is the tcmperature at which the particular pa~cent
weight loss is observed, utilizing a DuPont ThermoGravimetric Analyzer *
at a heating rate of 20~C in nitrogen. Althou~h nons of the st~hili~ers
were deleterious to stability, only those desi~nated 2 and 7 exhibited
si~r,ificsnt stability advantages.
The stabilizers studied were:
1. DLTDP (dilauryl thiodipropionate);
2. TNPP (l-isnony4Jha~yl phosphite);
3."1rganox'~010 (tetrakis(methylene(3,~di-t-butyl-4-hydroxy-
hydrocinn~" ,ale))methane);
4. DTDDS (di-t-dodecyWisulfide);
5."1~afo~"188 (tris-(2,4~i-t-butylphenyl)phosphite);
6." W~slon"*818 (di ~ea.yl pentaerythritol diphosphite);
7."Cyanox 1790 (tris~4-t-buty1-3-hydroxy-2,6~imethylbenzy1)-s-
bia~;ne-2,4,~(1 H,3H,5H)-trione;
8. " Irganox '~ 076 (octadecyl 3,Wi-t-buty~4-hydroxyhydrocinna" ,ale);
9. Topano~ CA (3~ ~ensate of ~,.,~tl"~l 6 t-butylphonol with
crotonahJel ,yde.
* l.,.~..-.rk (ea~h instance).
1.~40~5
T~RI F XVI
WEIGHT LOSS
STABILIZER (PPM) TEMPERATURE
_______ ---------------------------- ~DEGREES C)
1 2 3 4 5 6 7 8 9
1 % 10 %
279 325
600 274 318
2000 281 328
600 280 327
2000 271 317
2000 275 320
300 286 345
1000 297 368
272 317
600 2000 279 323
2000 2000 278 322
600 2000 280 323
2000 2000 278 321
2000300 291 358
600 2000600 280 324
273 319
600 273 318
2000 271 318
600 272 319
2000 272 319
600 2000 273 320
2000 2000 274 321
600 2000 285 328
-2000 2000 279 322
600 2000 296 333
2000 2000 298 338
600 2000 286 328
48
13gO065
TARI F X~ ;ontinllGtt)
WEIG~T LOSS
STAaILIZER ~PPM) TEMPERATURE
(DEGREES C)
1 2 3 4 5 6 7 8 9 - - __________
1 % 10 %
2000 2000 285 325
2000 285 325
2000 600 278 . 321
2000 2000 277 321
2000 600 276 321
2000 2000 277 319
1000 280 319
2000 285 323
4000 291 329
100 1000 285 329
300 1000 289 331
100 2000 289 327
300 2000 292 335
600 2000 282 325
1000 2000 288 325
1000 4000 291 331
2000 4000 291 331
2000 278 318
2000 278 322
1000 2000 277 316
300 2000 285 326
1000 2000 280 321
600 2000 286 327
49
1~4006~
FXAMPI F 69
This example illusl.~les the preparation of a larger amount of graft
eopolymer to be used in many of the folbwing studies. The process and
eG",~osition of Example 52 was tollowed with some variations. Several
preparations were combined. In all but the last of these preparations, radieals
are generated at the rate of 0.000070 moles per liter per minute (radical flux).Monomer and initiator are fed over 120 minutes and the theoretical (100%)
conversion) solids at the end of the rea~,1iol~ is 50%.
A 380-liter reactor equipped with a pitched-blade turbine agitator was
eharged with 86.4 kg of the hydrocarbon solvent an~ 34.5 kg of polypropylene
homopolymer, mfr=4. After deoxygenating (applying vacuum to degas,
followed by pressurizing with nitrogen to atmospherie pressure) through three
cyeles, it was pressurized to 103 kPa with nitrogen and heated to 1 50~C over 2
hours. A pressure of 241 kPa was maintained while the batch was held at
1 50~C for 3 hours. Two solutions were added over a fifteen minute period. The
first consisled of 59 9 of DTBPO in 841 9 of the hydrocarbon solvent. The
second consisled of 0.32 kg of ethyl acrylate and 6.14 kg of methyl
methacrylate. Addition of the first solution was then continued at a lower rate to
feed an AchJ;tional 103 9 of DTBPO and 1479 9 of the hydrocarbon solvent over
105 minutes. At the same time the monomer addition of 2.26 kg of ethyl
acrylate and 43.0 kg of methyl methacrylate was continued over 105 minutes.
neP--,tion exotherm incr~ased the temperature to about 1 60~C. After the feed
was complete, 5 kg of the hydrocarbon solvent was fed into the reaction
mixture.
25 . The reaction mixture was held in the reaction kettle for an additional 30
minutes. It was then trans~er,dd to a second kettle which was also under
pressure at 1 50~C. During the transfer a solution of 80 g of di-tertiary dodecyl
disulfide in 320 9 of the hydrocarbon solvent was added to the second kettle.
Also during this transfer three 4.53 kg portions of the hydrocarbon solvent were
... . . ,. ,. .~
134006,j'
fed into the reaction kettle. Material in this second kettle was fed to a 20.3-mm
We~ing Engineers twin-screw sxtruder where devol~ on occurred.
During the devolatilization the next batch was prepared in the reaction
kettle. It was transferred to the extruder feed kettle while extrusion continued.
In this manner several batches were made in a semi-batch~ manner that is
L~lc~ ise in the reactor with continuous feed to the extruder.
In the final prep&r~tion of the blend radical flux was 0.000050 (42 9
DTBPO + 858 g of the hydrocarbon solvent in the first feed 73 9 DTBPO +
1502 9 of the hydrocarbon solvent in the second feed).
o The final blend designated Example 69 was prepared by blending
pellets from 13 batches prepared as described and one batch of the final
variant. All sarnples from individual batches gave acceptable sag resistance
when tested in polypropylene.
FxAMpl F 70
The following example illustrates that improved stability can be imparted
to the graft copolymers of the present invention by copolymerization of an
alkylthioalkyl monomsr spccifically ethylthioethyl methacrylate.
The stability of graft copolymers prepared with alternate monomer
cG",positions was also evaluated. All were prepared according to the
pr~.c6dure for Example 4 except that the monomer co",position varied and the
product was isol~ted by ev&pGIvdtil)g solvent instead of by devolatilizing in anextruder. The monomer compositions and the TGA resuKs are summarized in
the table below. The al~brel,iation EA indicates ethyl acrylate; MMA methyl
~"etl,aclylate; ETEM~= ethylthioethyl methacrylate and MA= methyl acrylate.
Weight loss (%) is the temperature at which the particular percent weight loss is
observed utilizing a DuPont ThermoGravimetric Analyzer at a heating rate of
20~C in nitrogen.
51
1~41106a
I~IF XVîl
Grafted Acrylic Temperature at Which Noted Percent Weight
Poly~r T.o~.~ O~llr~ ~y T~.~ AnA 1 yc ~ Q ~~~)
1 % ~ % 5 % 10 %
95% MMA, 5% EA 221 274 307 333
95% MMA, 5% EA + 260 289 314 346
O.05% ETEMA
95% MMA, 5% EA + 281 305 335 360
O.25% ETEMA
95% MMA, 5% MA . 254 290 317 325
FXAMPlF 71
This example illustrates that an altemative Ille~llGJ reported for the
preparation of ",eU,a~lylic ester//polyolefin graft copolymers does not
produce a po~rmer useful in il"~ro~ resistance to sa~ging of
po~propylene. Exampb2OfU.S. Patent 2,987,501 was repeated, wherein
linear low-density polyethylene hG",opoly..ler (mtr~2.3) was immersed
in fuming nitric acid for 30 minutes at 70~C, removed, washed with water,
and dried. Thie treated polyethylene was then suspended over refluxing
- methyl ",ethacrylate for 4 hours. The polymer was exl,~ct~ with methyl
ethyl ke~one, as taught in the reference, to remove ungrafted poly(methyl
",etl,ac~ylate). The ",olQ~ul~ weight of the ungrafted polymer was
determined by ~el permeation chro")at6~.~phy to be Mw=430,000, Mn
~ 70,000.
13~0065
T~RI F XVIII
Weight of Weight before Weight after Weight
polyethylene, reaction (after reaction and of polymer
~. n~trAt~on), g. e~tr~ct;on. g extr~cte~
3.397 3.48 5.964 4.40
Thus, the graft copolymer ferrl,ed was 43~/O PMMA and 57% PE. The total
sample prior to exl~action was 67% PMMA, 33% PE, and the efficiency of
yr~ing of the PMMA was 63.1%.
The resultant graft polymer, from which the ungrafted polymer had not
been removed, was blended at the 4% level into the polypropylene resin of
mfr=4 used as a standard for testing sag resistance. The graft copolymer of thisexample did not disperse well, and visible, large, unJispersed fragments were
seen. The sag value (0.31 ) was worse than for the unmodified resin (0.18) or
for resin modified with an equivalent amount of the graft copolymer of Example
69 (0-02)-
The graft copolymer of this example was also milled into linear
low-density polyethylene (mfr 2.3) in the manner taught in Example 59. Poor
dispersion in polyethylene was also noted, with large chunks of the
u(,cl;spersed modifier visible. Sag resistance was determined at 150~C as in
Example 59; sag for the unmodified control (by the sag slope test) was 0.39,
and for the graft copolymer of this example, 0.23. By comparison, sag when
using the graft copolymer of Example 4 would be expect~ to be well below
0.10.
53
- - 13400~a
FXAMPI F.Ci 7~
This example illustrates prepz.r~tion of blends of graft eopolymer with
polyprop~lene resins to form pellets useful for further proc~ssing into extrudedor molded artieles.
The gratt eopolymer of Exampl- 69, not separated from any un~rafted
polypr~pylene or acrylie poly...er, was used as 3.2-mm long pellets eut from
an extruded strand.
The poly~.,u~,ylene resins used wer~nAristeeh'~1-4020F (Aristeeh
Chemieal CG.~Gr~tion, Pittsburgh, PA),'~i~-lG,lt'~523 (Himont Corporation
Wilmington, Delaware), and'~exene" 14S4A (Rexene Corporation Dallas, TX).
Characte.ialics are shown in Table Xlll; the term ~eopolymer in the table
means a eopoly-"ar with ethylene.
The ~raft copoly.,-Er was blended at 5% with the polypropylene resins
by tumbling. The blend was then extruded into strands through a""~3an 60-"*
mm, twin-serew extruder equipped with screws of 32:1 len~th/diameter ratio;
the al-ands were cooled and choppe~ into pellets. Various feed rates and
serew speeds were utilized. Conditions for the unmodified and modified resins
used to obtain large-seale samples are sum"-ancsJ in Table XIY. Sag tests as
de~,il,ed in Example 1 were con~ucte~ on several other samples of ",odified
resin pr~eesced under varying conditions, and the results were comparable to
those r~po,l~ bebw in Table XIX.
* Trad~~mark (ea~h instance).
54
.
~ .
,~ '.
. ~
1310065
T~RI F XIX
Rlen~.~ of PolyDropyl~ne With Meth~yl MethAcrylAte Gr~ft Copolymer
An-l Control s
Ex. 69
ExampleGraft, P~IYDr~PYl~ne MAtrix Resin Sag
phr ~Am~ MFR Co~osition
72 -- Aristech TI-4020F 2 copolymer 0.23
73 5 0.02
74 -- Himont 6523 4 homopolymer0.36
0.11*
76 -- Rexene 14S4A 4 copolymer 0.35
77 5 0.14
~ Sample tore on testing; other blends processed at slightly
different conditions gave sags of 0.06 to 0.09.
1340065
T~r~l F XX
Process~n~ C~n~tt;on~ for Pr~-Rl~n~ of T~hle XIX
Example: 72 73 74 ~ 76 77
Modifier: -- 5% -- S% -- 5%
Feed Rate, kg/hr ~Set)90.7 181.4 90.7 181.4 181.4 181.4
Feed Rate (actual)90.2 185 89.8 181.4 178.7 182.3
Screw Speeds 101 200 100 200 200
200
Drive Amp~ 103 121 97 111 112 112
Kg-m/sl 1258 3033 1184 2811 2~11 2811
Head PresQure (kPa)21372758 1448 2068 2275 2206
Barrel Temps. (~C)
Zone 1 163 163 163 163 163 163
Zones 2 - 8 204 204 204 204 204 204
Die 204 204 204 204 204 204
Melt Temp. ~C 213 222 208 216 217 217
.
1 - Power applied to extruder screw.
FXAMPI FF 78- 83
;
This example illustrates preparations ot blends of graft copolymer
with other pobrpropylene resins on difterent compoundin~ equipment to
form pellets usetul for turther pr)cessin~ into film or profile. Th~!Amoco- *
6214 is a film ~rade polypropylene resin containin~ a clarifier. The
~- Eastman 4E1 1--ls an impact-extrusion grade propylene-ethylene-
copoly-"er resin used in profile extrusion. In the present case both 1%
and 5% by wei~ht of the graft copolymer ,les~-ibed in Example 69 were
used to torm the blends.
56
* TL~ ~rk
** Tr;~Apm 3rk
;r
~ ' ' ' ' -- .
. .. . . ..... ~.~ . . , .. . .. ~ ,.. . . .. . .. ..
13 10065
The two polymers were tumble blended, and the mixtures ted to an
83 mm'~emer-Ptleiderer'~o-r~tatin~, intermeshing, twin-screw extruder
of 24/1 W ratio. The pelbts were continuously ted to the extnJder by
means ot art~Acrisorr~loss-in-weight teeder, melted and mixed in the
extruder, extruded throu~h a 33-strand die, cooled in a water trough,
dried, pelletized, and packa~ed. The machine cor,ditions for the
individual l~lcl)es are as follows:
T~RLF Xxl
Co~Dos;tions of Rlen~.c An~ ~Atr;Y Polymers
~x~m~le% ~i fi~r ~trix Poly~er
! 78 -- "Eastman"4Ell Copolymer
79
81 -- "Amoco 6214"Homopolymer
82
83 S
* Tr~A ~ rk
1349065
T~RI F XXII
Pre~r~tive Con~it;o~s for VArious Rlen~.~ of T~hle XXI
TP~er~ture, ~C
Ex.79 Zone set point/~ct-l~l Con~tions
Z-1 229 / 229 RPM- 125
Z-2 235 / 216 TORQUE- 73-75 %
Z-3 249 / 227 FEED SET- 65
Z-4 213 / 302 VACUUM- 380 mm Hg
Z-5 235 / 221 MELT TEMP.- 227~C (STRANDS)
Z-6(DIE) 227 / 227 RATE- 150 kg/hr
Z-7~DIE) 238 / 241
Ex. 80 Zone set ~oint/~.tl~l Con~it;ons
Z-1 229 / 229 RPM- 125
Z-2 235 / 216 TORQUE- 73-75 %
Z-3 249 / 235 FEED SET- 65
Z-4 213 / 302 VACUUM- 355-380 mm Hg
Z-5 235 / 232 MELT TEMP.- 205-207~C
Z-6 241 / 241 RATE- 218 kg/hr
Z-7 238 / 238
Ex. 82 Zone set ~o;nt/~ctu~l Con~itio~s
Z-1 288 / 288 RPM- 90
Z-2 296 / 304 TORQUE- 50-53 %
Z-3 299 / 260 FEED SET- 50
Z-4 252 / 316 VACUUM- 203 - 253 mm Hg
Z-5 293 / 293 MELT TEMP.- 223~C
Z-6 266 / 232 RATE- 116 kg/hr
Z-7 268 / 266
58
. ,. . , " ., , ~, . ~ ,.
1 3 1 0 ~
Ex. 83 Zone qet point/A~tl-~l ron~t~on~
Z-l 288 / 28S RPM- 90
Z-2 293 / 272 TORQUE- 50-56 %
Z-3 299 / 254 FEED SET- 50
Z-4 224 / 310 VACUUM- 304 - 329 mm Hg
Z-S 266 / 249 MELT TEMP.- 226~C
Z-6 266 / 229 RATE- 122 kg/hr
Z-7 268 / 272
FXAMplF.~ 84-87
This example illustrates the use of a graft copolymer of the present
invention in the prepar~tion of bottlss from polypropylene ,-,alenals.
The graft polymer of Example 69 was blended at various levels up
to 5% by wsight with either of two commercial polyplopylenes used for
blow moWing of bottles The matrix poly...er of Example 84 was a
propylene lancJon) copoly."er believed to contain 2-4 % ethylene,
supplied by ~na Oil & Chemical Co., Dallas, TX, as"Fina'7231, mfr~2.
The matrix polymer of Example 86 was a propyl~ne homopolymer,
mfr~2, supplied by Quantum Chemical, USI Division, Rolling Meadows,
IL as~l~orchem~200GF. Blends were made by tumblin~ the resins.
Samples were injection blow molded on a"Joma~machine, model
40, (Jomar Corporation, Pleasantville, NJ). The resin blend, in melt
form, was injl~cted into a four-cavity mold (two cavities being bbcked
off) over a core pin with an air hole at the end to form an i.lflatable
puison. The mold was heated and was designed to produce a pd~ler-,
at the far end which will ailow a cap to be ~tlacl,ed after molding.
Ten,pcr~t~lres of the mold were cont,~"ed at the bottle neck, bottle
walls, and bottle bottom. The parisons wore conveyed to a seconJ
59
, ., * ~ll,.r~. .. ;3rk (each instance) .
1340065
station where ~hey were ;ntlal~ to torm the bottb shape, and then to a
third station where they were cooied and re,-~v~:l. Bottles, which were
a 103.5 ml spice bottie, were judged versus non-modified controls for
surface 91OSS, ciarity, unifu-l--i~y of thickness, wall sl~.lytil, and the like,as well as to the ease of molding.
T~RI F XXU¦
Molding Conditions for Bottles
T~er~tllres. ~C.
I ~XA~pl e BeslnGr~ft~% ~ Q~Qm ~all ~k
84 84 ___ 243 77.7 104 48.9
84Ex. 69, 5% 249 82.2 110 48.9
86 86 --- 243 77.7 104 48.9
87 86Ex. 69, 5% 249 82.2 110 48.9
When bottles from Example 85 were compared with their controls
from Exampb 84, a sli~ht improvement in 9bss, notable increase in
conlac.t clarity, and noticoable i",pro1~ol,~nt in stiffness were observed.
Similar adva,.l~es over the control were seen with at a 1% level of the
~raft poiymer with the matrix resin of Example 84. The clarity effect was
not seen with bottles from Example 87 over control Example 86.
For re~ons not fully under~toGJ, the same additive at 5% was
cbbterious to the for,..~tion of bottles from ho,.-opolymer or copolymer
of hi~her mett flow rate, even wrth a,~prop~iate adjustments in
pr. ~ssin~ temperatures; much of the probbm was Assoc-~lscl with
poor Jispcr;,;on of the modifier. Such poor dispersion has not been
2~ seen in other cG,-"~ounding, pr~s.sing or testin~ operations. A slightly
stiffer bottle of i.l,pro~d gloss could be bbwn with the ~raft polymer
additive at 0.5 weight percent, relative to a control with no additive .
. ~ :
, . ....... ...
~ 1340065
A pre-blend (Example 73) of 5% graft copolymer with another
mfr.2 high-impact copolymer yielu~d bonles with severe ~"alelial
non-unifo"";ty. A dry bbnd of 0.5% graft copolymer with this same resin
(the resin of Example 72) gave bottles with improved gloss and contacl
clarity.
FXAMpl F~: ~R- 94
These examples illustrate the utility of a graft polymer of the
present invention in the preparation of polyp,opylene foam and foamed
sheet. In the examples a ho".Gpolymer of polypropylene (Example 72)
- 10 mfr.2 a pre-blend (Example 73) of that polypropylene with a
m~ll,acrylate//polypropylsne graft copolymer, and a mixture of the
Example73 pre-blend witlh 1% talc (d~si~nsl~ Example 88) wer
employed; into all pellets were b'~nJed A"~pacet"40104 to inco",or~te
a blowing agent."A",p~~t'~lowing agent is a 10%-active proprietary
chemical blowing agent dispersed in polyethylene. It is supplied by
A,npacet CG".Gralion, 250 South Terrace Avenue Mt. Vemon NY
,.
10550. When 10 parts of Ampacet are blended there is 1 part
pn:~p,ietary blowing a~ent in the formulation.
The polymer mixture was p,ocessed in a 25.4-mm single-screw
extruder produced by KilJion Extruders Corporation, utilizing a 24:1
bn~th/diameter screw of 4:1 cG,-"~,ess;on ratio, and a 1-mm-diameter
rod die. Extrusion conditions are summarized below. The unmodified
polymer exhibited severe fluctl ~a~ions in die pressure (6900 - 12 400
kPa); the blend contalnin~ 5 parts of the graft copolymer could be
extruded at a constant di~ pressure. In both cases ~ood cell unifo,-"il~r
was observed. Uniform larger cells were noted in the gratt-
polymer-modified blend when the amount ot active foa",in~ ingredient
* Tr~l~rk
61
~'
1340065
was increased to 2%. The presence of 1% talc in the modified
polyolefin produced the best cell stnJcture and fastest line speed.
Foam densities of the rods were measured according to ASTM
Standard Method D-792 M~thocl A-L. Although the unmodified matrix
polymer pro~uc~ the lowest-density foam the modified polymer foams
in ~eneral had a regular foam~ell structure.
The three ",ale,ials were also processed on a similar line with a
202-mm cast ~Im die and a heated collecting roll to yield foamed sheet;
here no significant differences in plocess;,-g were seen among the
three resin blends. The individual sample preparations and results are
shown in Tab~e XXIV below.
T~RI F XXIV
Type: Rod Rod Rod Sheet Sheet Sheet
Sample:Ex. 89 Ex. 90 Ex. 91 Ex. 92Ex. 93Ex. 94
Poly~r Qf:F.x . 7~F.X. 73 ~x. 88 F.x . ~1~x . 73 F.x . 73
Talc, wt% -- -- 1 -- -- --
Foaming
agent,wt %
Extruder rpm80 80 80 75 75 75
Melt temp.,~C214 208 209 227 227 227
Melt pressure, 70-
kg/cm2 127 127 140 56 42 42
Puller speed, 13 15 23
meters/min
Sample Density, 0.469 0.6640.733
g/cm3
62
... . ... . .. . ~ . .
1~ lOOfi5
FXAMPI F.~ 95 - 98
This example illustrates the utility of a ~raft copolymer of
~olypr~pylenel/methyl m4~hacrylate in lhe prep~r~tTon of blown
~olypr~pylene film. Film was blown from the control polypropylene
hG.~poly.. ar of Example 74, the pre-blend of Example 75 which
contained 5 wei~ht percent of the ~raft copoly--ler of Example 69, and
dry blends of the polypropylene of Exampb 74 wlth 1 and with 5 parts of
the graft cop~y-oer of example 69.
Blown fflm was pro~ce~ on a'l<illion"blown film line (Killion
Extruders Co., Cedar Grove, NJ), which consfsts of a 25.4-mm, single-
o screw extruder operatin~ d a melt temperature of about 216~C., a 50-
mm spiral ~anJIel die, air input for producin~ a bubble, and a Killion
vertical-blown -film tower. The blown-film tower contains two nip rolls for
collapsin~ the bubble and a means tor pullin~ the film through the nip
rolls. The die and pull sp~eds are adjusted to produce tilm about 5.6
mm thick (two thicknesses) and either 108 or 165 mm wide, the blow-up
ratios being 2.125 and 3.25 respe~ ely, at respecti~e top nip speeds of
7.65 and 5.94 meters/minute.
T~hle XXV
Film of Materials Thickness
20 E~am~
. .
Ex. 95 Ex. 74; no GCP 0.051 - 0.066
Ex. 96 Ex. 75; 5% GCP, Cmpd. 0.056 - 0.064
Ex. 97 Ex. 74; 5% GCP, Dry Blend 0;051 - 0.058
Ex. 98 Ex. 74; 1 % GCP, Dry Blend 0.051 - 0.058
63
* TrAA~I'lA l~k
1340065
Himont 6523, mfr=4, homopoly..,er polypropylene was blown into
0.02~mm-thick fflm (singb layer) as Example 95 (control). The bubble
was slightly lop~icle.J, and the frostline (onset of crystallization) was at
an angle to the die. A lopsided bubble results in less uniform film
thicknesses
With 5% of the graft copolymer of Ex. 69 present, the bubble of
Example 96 was stebil;~J, the frostline lovolled, and the frostline
moved closer to the die. Both 108- and 1 65-mm, lay-flat films were
produced Although some fluctue~ion in die pressure was noted when
forming the latter film, it had the most stable bubble.
This increase in bubble stability was also observed with the 1%
and 5% dry blends of Examples 97 and 98. No significant differences in
film appearance was observed between the 5% precompounded
blsnds and the dry blends.
The modified films had decreased film see-through clarity.
Contact clarity remained urlchanged. No difference in edge-roll color
was observed between modified and ur,i"GJified film.
The ~openability~ of neat and ",Gdified film was tested. Although a
very ~u~lit~tive test (the collarsed film is snapped between the fingers
and one feels how well it opens), no difference between the unmodified
and ",G.Jified resins was observed.
FXAMpl FS 99 -104
The experime!lts illustrate the use of the graft polymer of the
present invention in producing polypropylene cast film. A single-screw
extruder, manufactured by Killion Co., was e~uippe~ with a 3.81-cm
screw of 24/1 length/diameter ratio, a 20.~cm x 0.635-mm cast film die,
64
1~40065
a chill roll and a torque winder for the film, was utilized. The extruder
melt temperature was 226~C. The melt was extnuded through the die
and onto the chill rolls, the take-up speed being ~djusted to produce film
of various thicknesses. Film thicknesses was measured, as was ~neck-
in~, an undesirable shrinkage of width. Film stiffness and edge roll color
were measured rluAIit~ively. Film thicknesses were adjusted
incrbasing line speed of the torque winder and lowering the extruder
output by reducing screw speed.
T~RI F XXVI
Filmof Starting Material Form
~amQ~
Ex. 99 Ex. 74 Unmodified
Ex. 100 Ex. 75 Pre-blend; 5% GCP
Ex. 101 Ex. 74 and Ex. 69 Dry blend; 5% GCP
Ex. 102 Ex. 81 Unmodified
Ex. 103 Ex. 82 Pre-blend; 1% GCP
Ex. 104 Ex. 83 Pre-blend; 5% GCP
GCP = grafl copolymer of Example 69
Films of the co"~osition of Example 99 were uniform and
consistent at thicknesses of from 0.25 mm to below 2.5 mm. Example
100 pro~uc~ ~cep~le film of improved edge color and with less film
neck-in. Example 101 also pro~uced less neck-in, but did not i",pro~/o
edge color. Both "~ifie~ versions yi~lded stiffer films at equivalent
thickness versus the control, allowing the film to be wound more easily.
The opacity of the film inc,.,asecl with the ~dilion of the grafl polymer.
1340065
With Examples 102 to 104, the neck-in differences were not noted
when the graft copolymer sdditive was present. The films at both 1 and
S weight percent graft copolymer were stiffer than the un",Gdiried
control (Examples 103 and 104 versus Example 102).
FXAMPI F 105
This example illuslr~les that bi~xielly oriented film can be
prepared from a polypropylene resin containing 5% of the
polypropylene/methyl methacrylate graft copolymer. Under the limited
condiliGns tested, which were optimum for the unmodified resin, no
di~lin~ advantage could be seen for the additive. At identical extrusion
and MW (machine direction orientation) conditions, the modified resins
couW not achieve and maintain the line speeds possible with the
unmodified resin during the TDO (transverse direction orientation).
The control resin was Example 81, mfr=2.2, high~larity
homopolymer marketed for film use. Pre-compounded resins were
Examples 82 and 83, containing respectively 1% and 5% of the graft
copolymer of Example 69 (under the extrusion conditions, a dry blend of
5 parts graft copolymer of Ex. 69 with the matrix resin of Example 81
gave very poor dispersion, leading to many gels and frequent film
breaks). The blends were processed in a 50.8-mm, Davis-Standard
single-screw extruder which conveyed the melt through a 0.48-meter die
and onto a 1.02-meter casting roll. An air knife was used to blow the
extrudate onto the casling roll. The casling roll r~ta~ed through a water
bath to completely quench the sheet. The sheet then was conveyed into
the MDO, supplied by Marshall and Williams Co., Providence, Rl, and
comprising a series of heated nip rolls, moving at speeds which cause
monoaxial orientation.
1340065
After the MDO, the film p~ssed through a slitter to cut the film to the
proper width and then onto a winder. These rolls were used to feed the
film into the TDO, which is an oven with three heating zones, rolls for
conveying the film forward, and clamps to grip and laterally expand the
film.
The film from Example 81 (unmodified resin) was drawn both
4.75:1 and 5.0:1 in the MDO, and couW be drawn 9:1 in the TDO. The
ur""~ified 4.75:1 MDO resin could maintain a TDO line speed of 8.69
meters/minute; the unmod~fied 5.0:1 MDO resin could maintain a line
speed of 6.85 meters/minute .
The film from Example 82 (1% graft copolymer) could receive a
MDO of 4.75:1 and TDO of 9:1 and maintain a 6.85-meters/minute TDO
line speed. Frequent film breakage was encountered at higher MDO
and higher line spseds. This biaxially oriented film appeared to be
slightly more op~que than the biaxially oriented film from Example 80.
No difference between the edge roll colors of film from Examples 81 and
82 was observed for MDO film.
The films from Example 83 received MDO's of 4.75:1, 5.0:1, and
5.25:1 at a TDO of 9:1. The best film was obtained with a line speed of
6.85 meters/minute and with the lowest MDO; tearing would occur under
more stressed conditions. Films from Example 83 were noticeably more
op~us and the frost line appeared sooner than with the control film of
Example 81.
FXAMpl F 106
This example illustrates a profile extrusion trial using
polypropylene modified with a graft copolymer of the present invention.
A single-screw extruder was e~uipped with a die and appropriate
cooling, pulling, and sizing equipment to form a profile in the shape of a
67
1340065
solid rod with l,Gri~ontal tlanges. The rod diameter was 4.83 cm.,
flan~,iGS 2.67 crn. (e~lendad beyond rod), and flange thickness 1.52 cm.
With un.--~itied resin (Tenite 4E11 copoly.--er, Easlll.an Chemical, as
described in ExampJe 78), sy...--.elry was difficult to ~--aintain Tn the
profile without sag or distortion. When blends of Example 79 and 80 (1
and 5% ~raft copolymer, respec(i~ely) were employed, the maintenance
of shape was i---p~ed.
FXAMPI F 107
This example illustrates the use of a graft copolymer blend of the
present invention in the ,-~odifioation of polypropylene to produce
improved plastic tubing. The polymers used were the unmodified resins
and the resins compounded with 5% of the graR copolymer of Ex. 69, as
d&~-il~cJ in Examples 72 to 77.
A 25.4-mm, single-screw'Killion"Extruder (Killion Extruders Co.,
Cedar Grove, NJ) was equipped with a screw of 24J1 l~ngth/diameter
ratio, a tubing die with an outer die diameter of 11.4 mm. and a variable
inner diameter, leadin~ to a 0.2~metar-long wder trough for cooling, an
air wipe, and a puller and cutter. Conditions and observations are
shown in Table below. Ovality is the ratio of smallest outer diameter to
largest outer diameter, as measured by calipers; a value of 1 means the
tube is unif~ round.
When tubing of good ovalit,v was produced from the u-""Gdifiad
resin, the mapr eff~t of the additive was i",pru;0ment in tubing stiffness.
With the resin of Example 72, where ovality was dimcult to control at
A~epteble output rates, the ~"GJi~ resin (Example 73) improved
ovality as well as stiffness.
* Tradem~rk 68
. ~' '''. .
13~0065
~le XXVII
Tllhin~ Pre~re~l from Polypro~ylene ar~-l M~lifiefl Polypropylene
Polymer Melt Melt Inner Ovality
Temperature, Pressure, Diameter
~C kPa(a) mm(~)
Ex. 72 217 8270 8.1 0.75
Ex. 73 214 6890 8.1 0.88 (b)
Ex. 74 185 9650 8.1 0.97
Ex.75 197 6890 8.1 (c) 0.77
Ex.76 184 6890 8.1 (d) 0.92
Ex.77 180 8270 8.1 (d) 090 (b,e)
(a) Extrusion rate equivalent for paired un",Gdified and ~I~ified
resin.
(b) Modified extrudate tube stiffer.
5 (c) Higher melt tsmperature required to avoid ~sharkskin" on tubing.
(d) With this hi~her mfr resin, re~uced melt te,l-peral.lre and higher
puller speed led to tubing of lower outer diameter.
(e) Modified tubing more op~lue.
FXAMPI F!:: 108- 109
-' 20 This example illust,ales the preparation of pre-compounded
blends containing talc. The talc used is a white, soft, platy talc of particle
size less than 40 ~mj known as'~antal'hIM-45 90 (Canada Talc
Industries Umited, Madoc, Ontario). It was ussd at the 20% level. The
polypropylene used was a hG",opoly...er of mfr.4, known as~ "Gnr*
6523. The graft copoly",~ir was ir~G.~,or~tsd at the 5-weight-percent
69
* T~At-.,~rk
?
~,
13~0065
level and was the graft copolymer of Example 69. The
compounding/preparation of these samples was carried out on a 30-mm
Werner-Pfleiderer co-rotating, twin-screw extruder. The materials were
tumble blsnded prior to the compounding.
TARI F XXVIII
Blend % Talc Modifier Matrix Polymer
Example 108 (control) 20 Cantal --- 80% Himont 6523
Example 109 20 Cantal 5% Example 75% Himont 6523
The preparative conditions for the blends are given in Table XXIX.
The extruder was operated at 200 rpm, with no vacuum, at rates of 4.5 -
4.6 kg/hour, and 85-86% torque.
T~RI F XXIX
Fxtn ~Qr 7f-ne Settin~s. ~C
FY~le 108 F~ lQ 109
Zone set ~int/~c~ual set ~inV~tual
Z-1 125/ 148 125/ 151
Z-2 220/ 218 220/ 219
Z-3 230/ 228 230/ 229
Z-4 230/ 242 230/ 241
Z-5 240/ 239 240/ 239
Z~ 240/ 239 240/ 239
Z-7 240/ 242 240/ 239
Z-8 (die) 225/ 239 225/ 239
Melt 239 243
~4~065
FXAMPI F~:; 110 ~
These examples teach the injection molding of polypropylene of
various compositions and melt flow rates, the polypropylenes
containin~ a graft copolymer of the present invention. In two examples,
a 20% loadin~ of platy talc is also present.
Polypropylene may be injection molded into useful objQcts by
employing a reciprocating-screw, injection-molding machine such as
that of Arburg Maschien Fabrik, I ossb~rg, Federal Rep~blic of
Germany, Model 221-51-250. In the preparation of test samples, the
extruder is equipped with an ASTM mold which forms the various test
pieces. The conditions chosen for molding were unchanged
throughout the various matrix and modified matrix polymers, and no
difficulties in molding were noted. Table XXX describes the blends
which are molded; Table XXXI teaches the molding conditions; Table
XXXII reports modulus values, Table XXXIII Dynatup impact data, and
Table XXXIV heat distortion temperature values for the modified
polymers and their controls.
In the following list of injection-molded polymers and blends, all
samples contain 1 or 5 weight percent of the graft copolymer of
Example 69. The polypropylene matrix resins are described in earlier
examples; HP is homopoiymer, CP is copolymer, the number is the mfr
value. The blends with talc are described in Examples 108 and 109.
All materials were pre-blended in the melt, excspt where a dry blend
from powder was directly molded. (C) is an unmodified control; (CT) is
a control with talc, ~ut no ~raft copolymer
All test Illetllods were by ASTM standard methods: flexural
modulus and stress are by ASTM Standard Method D 790, heat
.. , .... ~ ~,
13 10~65
distortion temperature under load is by ASTM Standard Method D 648
and Dynatup impact is by ASTM Standard Method D 3763.
Table XXX also includes the melt flow rates (mfr) for the
ur""Gdi~ied and pre-compounded blends. In most cases the melt flow
rate is unchanged or slightly decreased in the presence of the graft
copolymer so that the melt viscosily under these intermediate-shear
conditions is not extensively incleaseJ. The melt flow rate is by ASTM
Standard Method D-1238 cGndilion L (230~C. 298.2 kPa) and has
units of grams extruded/10 minutes.
1~40065
T~RI F XXX
Fx~le Matrix ~.r~ % Talc.% n~-Rlend? mfr
74 (C) HP,4 -- -- -- 4.40,4.06
HP,4 5 -- -- 6.07
110 HP,4 5 -- YES
108 (CT) HP,4 -- 20 ~~
109 HP,4 5 20 --
76 (C) CP,4 -- -- -- 4.47
77 CP,4 5 -- -- 3.75
111 CP,4 5 -- YES
72 (C) CP,2 -- -- -- 2.37
73 CP,2 5 -- -- 2.02
112 CP,2 5 -- YES
78 (C) CP -- -- -- 2.92
79 CP 1 -- -- 2.04
CP 5 -- -- 2.12
81 (C) CP -- -- -- 2.33
82 CP 1 -- -- 3.81
83 CP 5 -- -- 2.16
73
1~40065
T~RI F
Cylind~ t~ nr~ res. ~C ~Settin~ma~cllr~
Feed -216/216 Meterin~ -216/216
Compression -216/216 Nozzle 216/216
Mold Temperatures, ~C
Stationary -49/49 Movsable -49/49
Cycle time, secor,ds
Injection fonNard -14 Mold Open -0.5
Cure -14 Total Cycle -0.5
Mold Closed -1.2
Machine readings:
Screw speed (rpm) - 400
B~k pressure (kPa) -172
Injection (1st stage)(kPa) - 861
The flexural modulus data from Table XXXII indicate the :,linanin~
effect of the graft cop~ly-.-er. Results are in me~r~A~ s (mPa).
,~
.
13~0065
T~RI F XXXII
FLEXURAL STRESS
Example MODULUS ~at max)
mP~ mP~
74 (C) 1470.6 43.8
1744.4 47.5
110 1783.1 46.9
108 (CT) 2768.0 52.0
109 2867.0 54.5
Table XXXIII su"""~.izes Dynatup impact data (in Joules) at
various t~-"pGr~ures for the blends and controls tested. The data
indicate, in general, slightly improved impact for the pre-blended
materials, a deterioration in impact strength on molding dry blends of
graft copolymer and matrix polymer, and an increase in impact slrenyll,
for the taic-modified bbnd also containing the graft copolymer.
134096~
T~l F XXXIII
Dynatup Impact (joulss) at
TestTem~r~llre ~C
Fy~rnple 2~ 15
74 (C) 4.9i2.7 4.4i1.5 3.8iO.3 2.6i. 41
5.7i3.4 4.6iO.8 2.7i1.5 3.4il.09
110 3.4i1.1 2.0iO.5 1.9i1.0 1.5i. 41
108 (CT) 3.0iO.5 3.4iO.8 4.2il.6 5.0i2.5
109 l.9iO.5 4.1i2.3 4.8il.8 5.0i2. 5
76 (C) 40.0iO.5
77 43.9iO.4
111 14.0i6.4
72 (C) 37.9i1.8
73 43.1i10.3
112 32.4i9.5
78 (C) 36.7iO.4
79 36.3i1.1
37.1iO.7
81~ (C) 13.3ilO.7 ---- 3.3iO.8 2.7iO.2
82 4.9iO.7 ---- 3.0i1.4 3.0iO.8
83 7.6i3.7 ---- 3.3iO.8 3.5+1.1
The large standard deviation at room temperature is suspect.
Table XXXIV presents heat distortion and hardness values for one
series. The modifiéd polymer appears to exhibit a slightly higher heat
distortion temperature and hardness, although there are
inconsisl6ncies noted. The Rockwell hardness values represent
76
1340~65
separate dete""inalions on two samples of the ",ale.ial trom the
indic~ted example.
T~RI F XXXIV
Heat Deflection Ternperature Rockwell Hardness
Example ~ ~rlMinl ~e At "~ IQ
-- 411 kP~ 1645 kP~
74 (C) 110.9 61.0 58.4 56.5
113.8 63.3 60.7 59.3
110 117.3 68.7 57.9 46.9
108 (CT) 128.2 76.8 57.3 64.7
109 124.7 81.9 65.4 63.7
FXAMPI F 113
This example illusl~tes the effect of the ",ol~aJlar weight of the
polyprop~lene tnJnk component of the graft copolymer on the sag
",~ificalion of polypropylenes of various molscular weights. Graft
copolymers were prepar~d from p~h,p~p~lene of various melt flow
rates. All modifiers were prepar~cl as in Exampb 58. The 35 mfr
polypropylene ~ lo,lt P~701~*was run at 6~% solids. The 12 mfr
polypropylene ~himorlt Pro-fax 6323) was nun at 60% solids. The 4 mfr
polypr."~ylene (Himont Pro-fax 6523) and the 0.8 mfr polypropylene
*
'~Himont Pro-fax"6723) were run at 55% solids. The molecular weights
- for the polypropylene base resins, where known, are ~iven in Table
XXXV, bebw.
These were ev~ tsd as melt ~Ir~,~tl, ;""~,o~ors at 4% by weight
in several of these same polypropylenes. Sttu~ard mill and press
conditions were used for all blends, except the 0.8 mfr/0.8 mfr
?7
* T.~ ~rk
r
l~OOfiS
polypropylene blends which were milled at 215~C and presssd at
21 5~C. Sag rates were measured by the standard procedures. The
sag slope at 190~C is reported in Table XXXVI, below.
T~RI F Xxxv
M~-~FR D~t~ for polyprQ~yl ~n~ e Res;n
Molecular-Weight WP;~ht-Aver~e ~le~l]l~r Welght x 105
.Sol~r~P l? ~fr PP 4 mfr PP 0.8 ~fr PP
(a) 3 4.3 7.1
~b) 2.45 3.05 3.5,4.7
(c) 0.27* 0.45* --
Source of Molecular-Weight Value: a) Supplier's data. b) Sheehan et
al, J. Appl. Polymer Sci., 8, 2359 ~1964). c) Mays et al, lbid.,
34, 2619 ~1987).
* These values are nl~mher-Aver~e molecular weight.
T~RI F XXXVI
Slope At 190~C for Olefin Rlen~ min-~)
polyprQDyl~n~ h~.~e r~c'n (96~)
~;f;er (4%)35 mfr PP1~ ~fr PP 4 ~fr PP0.8 ~fr PP
none 1.6 0.52 0.25 0.099
35 mfr PP based 1.8 0.52 0.23 0.074
12 mfr PP based 1.2 0.41 0.034 < 0.02
4 mfr PP based1.0 0.16 0.022< 0.02
0.8 mfr PP based 0.64 0.16 0.031 << 0.02
In all cases except where a high-melt-flow base resin was
modified with a graft polymer having a trunk of high-flow-rate (low-
moleaJI~-weight~ polypropylene, sag improvement was observed. The
molecular weight for the resin of mfr=35 is not accurately known; it is
78
.. .".u . ,. .. ~ .. ." , .. . .
1340065
believed to be made by thermal/oxidative pr~ssing of a higher
oclJl-r weight resin. Such a process wouW both lower the
moiecular weight and narrow the originally broad molecular-weight
distribution.
FX~MPI F 1 14
This example illustrates the effectiveness of the graft copolymers
of the present invention as compatibilizing agents for polymers that are
othenrJise poorly compatible. In this example a polyolefin, a polar
polymer, and the graft copolymer of the present invention were
compounded in an intermeshing, co-rotating, twin-screw extruder
(Baker-Perkins MPCN 30) with a screw length-to-diameter ratio of 10:1.
The cG"~ounder was run at 200 rpm and temperatures were adjusted
to accomr"Gdate the polyrners in the blend and achieve a good melt.
The melt temperature in the compounding zone is recorded in the
second column of the table. The melt was fed directly to a 38-mm,
single-screw, pelletizing extruder with a length-to-diameter ratio of 8:1.
The melt temperature in the transition zone between the compounding
and the pe"~ti~ing extruder is shown in column 3 of Table XXXVIII,
below. The melt was extruded into strands through a die, cooled in a
water bath, and cut into pellets.
Table XXXVII below summarizes the polymers which were used in
the blends of the present example, while Table XXXIX shows that the
graft copolymer has little effect upon the tensile strength of the
unblended polymers, that is, it does not act to a significant degree as a
toughening agent. In the 5~lhse~luent tables, Tables XL and XLI,
improvement in tensile strength of the blended polymers indicates an
increase in co,.,patibility of the blended polymers with one another in
the presence of the graft copolymers of the present invention.
79
1~006~
Under the proper co."pounding coficlilions, an increase in
comp~ibility may also praduce a decrease in the size of polymer
domains in the blend. Scanning electron micr~.~copy confirms that in
some of these examples, sigr,ificant domain-size reductions occur when
the graft copolymer is added. For example, the polypropylene domains
average 2 micrometers in the 70 PMMA / 30 PP blend of example 114.
The addition of 5 phr co",palibilizer reduced the domain size to 0.5 llm.
The addilion of 15 phr con"~alibilizer reduce~ the domain size to 0.43
m. Although not all ot the domain sizes were reduced, several others
were reduced by 10-30% bythe addition of 5 phrcGi"palil,ilizer. This is
a further suggestion that the cGi"palibilizer is acting on the inle,face of
the polymer domains rather than on the individual polymers.
Table XLI summarizes the comp~tibi';~ing effect of the graft
copolymers upon the various polymer blends.
1310065
T~RIF Xxxvll
poly~rs Use~ ~ n the Rl ~n~ Fx~ es
Other
Polymer and Designation Grade Spec. Specifi-
in T~hles pro~llcer ~esi~n~t;on ~r~V. ~Ations
SAN Monsanto '~ustran"~AN 33 1.07 mfr~l4
Styrene-Acrylonitrile ASTM D 1238
Polymer Cond.(I)
PA66 DuPont "Zytell'~01 1.14 mp-255~C
Nylon 6-6 ~D2117)
¦ PET Eastman IlKodapa~ PET 1.4 mp-245~C
Polyethylene Kodak 7352 (DSC),
Terephthalate iv~0.74
EVOH EVAL Co. "Eva~'EP-E105 1.14 44 mole% E,
Ethylene Vinyl of America mp-164 C,
Alcohol Copolymer mfr~5.5
(190~C,
2160 g)
PC General "Lexan"121 1.20 mfr~l6.5
Polycarbonate Electric ASTM D 1238
Plastics Cond. (O)
1 PVC Georgia SP-7107* 1.35
PolyvinylChloride Gulf Corp.
PMMA Rohm and "Plexiglas~ 1.18 mfr=15
Poly~Methyl Haas Co.
Methacrylate)
EP Exxon "Vistalo~l719 0.89 54 Mooney
Ethylene Propylene (D-1646)
Copolymer
HDPE Phillips "Marlex"* 0.950 mfr=4
High-Density 66 Co. HMN 5060
Polyethylene
PP Hlmont "Pro-faxl'6523 0.903 mfr~4
Polypropylene
EVA DuPont ~Elvax"650 0.933 12% VA
Ethylene Vinyl Acetate mfr~8
81
* Tr~Fm~rk (each instance).
.~
13~006a
TARI F XXXVII ~nntin~lA-l)
Other
Polymer and Designation Grade Spec. Specifi-
1n T~hles pro~llcer nes~gr~At~on Grav. ~At;ons
LLDPE Exxon n Escorene "* 0.926 mfr~12
Linear Low-Density LL-6202
Polyethylene
PS Huntsman PS-203 1.06 mfr=8
Polystyrene Chemical ~crystal)
PBT General " Valox' 6120
Poly(butylene Electric
terephthalate)
PA6 Allied " Capronn8253 1.09 mp=21~C
Nylon 6 Signal
ABS Dow " Magnum"341 1.05 mfr=5
Acrylonitrile- Chemical
Butadiene-Styrene
Resin
PC/PBT General nXenoy "~101 1.21
Polycarbonate/ Electric
Poly~butylene tere-
' phthalate alloy
¦!
* Tr ~ ~rk (each ~nstance.
~
r ~
~,. .
1~4006:~
T~Rl F XXXVIII
melt t~m~er~t~res ~~C)
~Qm~olln~er trAnsit ~ on
PMMA 225-235 210-220
SAN 220-230 210-220
EVOH 205-225 200-215
PA66 260-275 255-270
PET 245-275 245-255
PVC 205-230 190-215
PC 250-290 240-270
The pelbts were dried and inj~ction mol~ed on a reciprocatin~-
screw injaction ",~lclin~ machina '(New ~ritair~Model 7~) into test
specimens.
*rrad~rk
83
.
13~006~
T~RI F XXXIX
.ffect of Co~tihilizer on polymer Tens;le Str~ngth
Te~s;le Strength.~ Shown in ~egAP~sc~ls (~P~)
snm~t;hili7er concentr~tion
pOly~r 0 ~hr 5 Dhr 15 Dhr
PMMA 65.44 64.7961.27
SAN 71.91 62.7455.89
EVOH 68.78 66.2163.78
PA66 64.82 64.6866.60
PET 58.26 59.3359.72
PVC 45.25 44.9745.22
PC 62.63 63.0563.70
HDPE 22.59 22.6624.14
PP 33.02 34.0333.95
EP 4.79 5.50 5.84
LLDPE10.91 11.8012.99
EVA 8.64 8.67 8.17
84
13~00~5
T~RI F Xl
TPns;le Stre~gth.~ (MPA) of RlPn~.~ of polyolefins An~ pol~r Polymers
30% pol Ar ~ol y~Pr 55% pol ~r ~ol ym~L 80% pol ~r ~ol ymer
polar
poly~Pr 0phr ~h~ 15~hx O~hr ~h~ hL Q~hL ~h~ 15Dhr
~~--~----------------- HDPE -----------------------
* PMMA 25.26 27.00 30.26 31.42 38.30 39.54 50.78 53.77 55.55
* SAN 25.77 28.09 30.57 34.71 41.51 38.33 51.88 55.08 51.23
* EVOH 26.57 26.80 27.74 33.18 38.00 39.58 49.24 51.32 50.79
PA66 26.94 28.85 29.72 38.34 38.11 38.33 61.22 65.62 69.23
PET 25.97 28.61 30.98 37.70 37.93 40.09 50.23 51.72 50.91
PVC 20.89 22.92 24.86 19.91 23.67 27.34 26.18 30.72 34.87
PC 25.66 28.80 30.93 31.11 35.20 38.53 55.61 50.41 51.92
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ p p _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
* PMMA34.02 35.37 37.81 40.23 43.45 45.84 46.40 53.70 56.6
* SAN33.67 38.76 41.05 37.67 47.65 46.08 41.11 54.12 51.81
* EVOH32.85 37.40 38.56 35.01 44.65 45.60 42.73 53.38 52.57
PA6632.06 40.29 40.38 42.72 52.17 51.10 64.71 67.84 66.15
PET32.93 33.80 35.15 39.47 43.81 43.64 37.67 53.12 54.04
PVC36.32 37.68 39.35 35.28 37.87 40.79 30.88 40.00 42.56
PC33.82 36.68 39.09 36.69 40.13 44.64 42.38 46.24 51.64
~~~~~~~~~~~~~-~-------- EP ------------------------
PMMA8.20 10.87 12.51 19.99 24.17 27.81 42.47 44.59 46.93
SAN8.10 12.53 14.11 22.14 28.82 28.15 45.92 50.68 44.58
EVOH12.19 12.04 11.69 24.92 24.66 23.17 41.29 42.39 42.70
PA6613.04 13.a4 12.36 27.62 27.98 26.33 40.87 48.77 43.48
PET7.94 8.40 11.13 20.22 20.43 22.27 33.72 37.00 38.87
PVC6.17 9.05 12.88 12.93 18.28 19.22 25.50 28.41 30.60
PC10.31 12.05 13.66 23.10 24.34 25.60 40.18 41.79 42.76
1340~65
TARI F ~tl ~ntin~
T~ns; le Strerlgth~ ~P~) of Rl~n~ of polyoleflns ?n~l pol~r PoLymers
30% ~olAr ~olyIn~r 55% pol~r ~olyln~r 80% ~ol~r Dolylner
polar
~ol y~r Ophr 5~hr ;L~ ODhr 5Dhr lSDhr Q~ 15phr
~~~~~~~~~~~~~-~------ LLDPE -----------------------
PMMA 15.23 18.63 20.90 24.88 30.68 32.84 48.95 55.36 54.14
SAN 15.78 21.08 22.57 26.50 35.76 36.71 47.52 56.92 48.84
EVOH 16.83 17.26 18.26 30.02 31.74 31.87 51.83 50.71 52.29
PA66 17.93 17.99 19.98 29.67 28.49 25.23 64.65 67.55 67.26
PET 15.33 18.09 20.35 25.53 28.23 30.78 45.02 46.16 42.87
PVC 14.72 14.12 15.73 12.45 18.09 20.50 25.99 30.54 33.69
PC 13.64 19.20 18.48 19.22 27.83 30.46 38.45 40.59 38.86
------------------------------- EVA ---------------------------
PMMA10.57 11.28 14.38 23.06 21.10 28.31 45.99 47.02 50.87
SAN12.40 13.62 15.22 27.97 27.29 29.35 48.94 52.01 46.14
EVOH13.13 13.97 16.59 32.41 28.65 35.43 50.97 50.28 48.81
PA6614.15 13.54 14.42 27.36 24.59 26.92 40.75 38.35 31.60
PET14.55 14.35 12.31 21.22 23.90 26.45 43.20 43.91 48.44
PVC7.69 8.28 10.25 13.40 14.29 18.17 19.22 23.76 28.12
PC14.05 14.54 13.52 19.78 21.79 24.85 39.26 40.55 41.46
- polar polymer levels are 20, 45,and 70% instead of 30, 55 and 80%.
86
13~006.7
T~RI F Xl I
Effect of Compatibilizer on Tensile Strength of Blends of
Polyolefins and Polar Polymers
Incre~se in Tensile Strength (~PA) fr~m the Com~tib;lizer
30% pol~r polym~r 55% Dol~r polym~L 80% pol~r polymer
polar
poly~r5 phr 15 phr 5 phr 15 phr 5 phr 15 Dhr
----------------------- HDPE -----------------------
PMMA 1.74 5.01 7.38 8.12 2.99 4.77
SAN 2.32 4.80 6.80 3.63 3.21 -0.64
*EVOH 0.23 1.17 4.81 6.39 2.08 1.54
PA66 1.90 2.77 -0.23 -0.01 4.40 8.00
PET 2.65 5.01 0.23 2.39 1.48 0.68
PVC 2.03 3.97 3.76 7.43 4.54 8.69
PC 3.14 5.27 4.10 7.42 -5.20 -3.69
_ _ _ _ _ _ .
*PMMA 1.35 3.79 3.22 5.61 7.29 10.22
SAN 5.09 7.38 9.98 8.41 13.02 10.i0
- *EVOH 4.56 5.72 9.64 10.59 10.65 9.83
PA66 8.23 8.32 9.45 8.38 3.13 1.44
PET 0.86 2.22 4.34 4.17 15.44 16.37
PVC 1.36 3.03 2.59 5.51 9.11 11.68
PC 2.86 5.27 3.43 7.94 3.85 9.26
87
.. , .. .... ,. , ~ ... ... . ..
1340~6S
T~RI F )~ ontin~
Incre~se in T~n~ile Strength ~YP~) from the Co~t;h;l;zer
30% po1~r poly~r 55% pol~r poly~r 80% pol~r polymer
polar
polym~r5 phr 15 phr 5 phr 15 phr 5 phr 15 phr
------------------------ EP ------------------------
PMMA2.66 4.30 4.18 7.82 2.12 4.46
SAN4.43 6.01 6.68 6.01 4.76 -1.34
EVOH-0.15 -0.50 -0.27 -1.75 1.10 1.41
PA660.01 -0.68 0.36 -1.29 7.90 2.61
PET0.46 3.19 0.21 2.05 3.29 5.16
PVC2.86 6.71 5.35 6.29 2.91 5.10
PC1.74 3.35 1.24 2.50 1.61 2.59
---------------------- LLDPE -----------------------
PMMA3.40 5.67 5.80 7.96 6.42 5.19
SAN5.31 6.80 9.26 10.21 9.40 1.32
EVOH0.43 1.43 1.72 1.85 -1.12 0.45
PA660.06 2.05 -1.19 -4.44 2.90 2.61
PET2.76 5.01 2.70 5.25 1.14 -2.14
PVC-0.59 1.01 5.64 8.05 4.56 7.70
PC5.56 4.85 8.61 11.24 2.14 0.41
----------------------- EVA ------------------------
PMMA0.71 3.81 -1.95 5.25 1.03 4.87
SAN1.22 2.81 -0.68 1.38 3.07 -2.80
EVOH0.83 3.45 -3.75 3.02 -0.68 -2.16
PA66-0.61 0.27 -2.77 -0.44 -2.40 -9.15
PET-0.20 -2.25 2.68 5.23 0.70 5.24
PVC0.59 2.56 0.89 4.76 4.54 8.89
PC0.49 -0.53 2.01 5.07 1.30 2.20
~ - polar polymer levels are 20, 45 and 70% insle~l of 30, 55 and 80%.
1~400 6 .~
T~RI F Xl ll
Con~tibili7~tion Fffect
E~E PP E;E~ LLPI)~
PMMA +~+ +++l +~+ +~ ++~
SAN +++ +++ +++ +~+ ++
EVOH ++ +++l o o ++
PA66 ++ +++l + + o
PET + ++l ++ ++ ++
PVC +++ +++ +++ ++l ++
PC ++ +++l + ++ +
+++ - compatibilization at all three polyolefin-polar polymer ratios (not necessarily at all
co""~dlibilizer levels)
I + - compatibiP~tion at two of the three polyolefin-polar polymer levels
+ - compatibilk~tion at one of the two polyolefin-polar polymer levels
15 ~ - no compatibilization seen at any polyolefin-polar polymer ratio at any co",p~libilizer
level
(1 ) - additional evidence for compatibilization in the reduction of domain size by
1 0-80%
FXAMPI F 115
The co",patil)ilizing sffect on selected additional polymsr pairs
was eve~u~ted in the following example. The blends were
compounded molded and tested for tensile strer~th as previously
de~ribed. The results in Table XLIII again indicate that the
co",~tibilizer has minimal or a negative effect on the polar polymers
but a positive effect on the polar / nonpolar polymer blends. A large
tensile sl-er"Jtl, improvemsnt is seen for the ABS / PP blend. Smaller
but significant improve,ne.~ls are seen for the blends of PP with PA6
and with PC / PBT. With the PS blends ev~4J~ted the effect was
negligible.
89
134006.~
T~RI F ~
tensll~ str~ngth.~ (~P~)
polar
polymer + blend1 +
15 phr 15 phr
polar nonpolar polar graft graft
polyr~r pol~8L pnlym~L copolym8~_ hl en~l cQDol ym~r
PBT PP 43.02 45.11 36.96 38.96
PA6 PP 56.11 51.67 43.50 47.04
PS PP 45.26 40.45 38.88 37.36
PS HDPE 45.26 40.45 36.48 33.76
ABS PP 51.25 52.25 32.25 42.55
PC/PBT PP 51.77 51.79 38.99 41.88
1 - blend in all cases refers to 55 parts by weight polar polymer
and 45 parts by weight nonpolar polymer.
The effsct of the gratt copolymer on multi-component blends such
as those representative of commingled scrap polymers are shown in
Table XLIV. In all cases a significant increase in tensile strength is
observed when the co",~ bili~er is present.
13~0DG5
T~RIF XLIV
cGil~Alihili7~tion of Mllllic~ nt Rl~n~c
Tensile
pol~r P~ly~r~ N~ol~r Poly~r~ tihil;?~r Strength
HDPE T.T.DpF. ~
12 7 5 33.5 33.5 9 none 16.27
12 7 5 33.5 33.5 9 5 17.67
12 7 5 33.5 33.5 9 15 21.77
12 8 - 35 35 10 none 18.62
12 8 - 35 35 10 5 19.98
12 8 - 35 35 10 15 22.16
12 - 6 36 36 10 none 17.06
12 - 6 36 36 10 5 i9.21
12 - 6 36 36 10 15 21.91
FXAMPI F 116
This example further illusl,~tes co"~p~ti~ tion of polymer
blends using graft co~o~.llera of the present invention.
Blends of ethybne-vinyl alcohol copolymer (Kuraray EP-F101A),
polypn~pllene ~Himon~6523) and ~raft copoly"ler were milled on a
7.62-cm X 1 7.78~m electric mill at 204~C to flux plus three minute~.
The stocks were pres~ at 204~C and 103 MPa for three minutes
(Carver Press, 12.7-cm X 12.7~m X 3.175-mm mold)and at room
temperature and 103 MPa for three minutes. Two graft copolyn,er~
were used in thTs exampb. Tne fTrst (Gratt Copolymer A) was a
polypropylene - acrylic graft copolymer pr~pa~ecl ~rom mfr.4
polypropylene hG",opolymer (100 parts) and a 93:2:5 mixture of methyl
* Tr~rk
A~
.~ .
1340065
methaerylate:ethyl acrylate:methaerylie aeid (100 parts). Polymerization
was done in Isopar E solvent at 1 60~C at 50% solids over one hour with
a di-t-butyl peroxide radiaal flux of 0.00012. The product isolated
eontained 44% aerylate. The second graft eopolymer (Graft Copolymer
B) was a polypropylene - aerylie graft eopolymer prepared from mfr=4
propylene homopolymer (100 parts) and a 95:5 mixture of methyl
",ell,ac~ylate:ethyl aerylate (150 parts). roly",erization was done in
Isopar E solvent at 1 55~C at 60% solids. The feed time was 60 minutes
and the radieal flux was 0.00010. The product eontained 53% aerylate.
AWition of the graft copolymer results in an inerease in tensile sl,en~
and modulus.
T~RI F Xl V
Co,l,~7~i~ n of FVOH ~nrl PolYpropylene
notched
graft Izod tensile tensile
EVAL PPcopolymer tensile strength modulus
(gr~m~ r~m~) (gr~m.~) (J/m) (~P~) l~P~)
0 21 29.85 2570
51 21 48.06 3190
52 22 46.75 3270
0 18 21.37 1930
15l 18 29.79 2140
152 13 30.41 2030
1 - Graft Copolymer A (see text above).
2 - Graft Copolymer B (see text above).
92
1340065
While ths invention has been described with reference to specific
examples and applications, other modifications and uses for the
invention will be apparent to those skilled in the art without departing
from the spirit and scope of the invention defined in the appended
claims.
93
