Note: Descriptions are shown in the official language in which they were submitted.
~;3Çia~r~
--1--
~ FIELD OF THE INVENTION
: ThiQ lnvention relates to proces~lng ald~ ~or
vlnylchlorlde polymers, and more particularly to
improved proces~qing aid composltions ~or vlnylGhlorlde
; polymers containing a dispersion aid polyme~ for the
improved disper~lon o~ ¢onventional proce~sing aids ln
the ~lnylchloride polymer.
Pol~meric processlng alds are widely used ln the
o productlon o~ polyvlnylchloride (PVC) articles to
improve the proce~sing performance Or P~C during
extrus~on, inJection and/or thermoformlng operations.
Proce~slng aid~ act to reduce the temperature requlred
for ~uslon o~ PVC, promote homogeneity and hot strength
o~ th~ PVG~ reduce melt fraGture, reduce plateout
~; durlng processlng~ ~nd impart better ductllity to the
rlnished product. Lowerlng the tempera~ure o~ ~u~lon
;~ results ln prolonged heat stability for PVC, allows for
a margin o~ ~afety when using regrlnd materlal, and
0 decreases the proce~sing tlme. Greater hot strength
and reduced melt fracture allows a processor to extrude
` or calender the PVC at a faster rate wlth improved
sur~ace quallty. Reductlon or elim1nation of plateout
allows ~or extended proces~lng runs without re~ects due
~.~
;, ~
536~
to plateout markoff and without time-consumlng
shutdowns ~or cleaning out deposits that would
lnterfere with melt flow and contribute to PVC
degradation. The homogenizing effect of processing
aids is very important in providing products having
signiflcantly improved ductillty and thermo-
formability. The uniformity of the temperature
dependent properties of PVC obtained with the inclusion
of processing aids improves the overall ability o~
processors to operate their equipment.
Processing aids generally also improve the tensile
; strength~ modulus and, to a smaller extent, the heat
distortion temperature of PVC but do not improve impact
strength and can actually reduce the impact strength of
PVC when added at high levels.
Various types of polymeric processing aids have
been deve~oped for use with PVC. These processing aid
polymers include acrylic polymers and copolymers, such
as hlgh molecular weight polymethyl methacrylate with
weight average molecular weights ranging from about
750,000 to about 7 million, copolymers formed
predominantly ~rom methyl methacrylate and minor
amounts of alkyl acrylates, and copolymers of acrylics
and styrene, styrene and acrylonitrile, and
poly(alphamethyl-styrene). These processlng aid
polymers may be homopolymers, single stage or multiple
stage copolymers, or graft copolymers.
~ Not all conventional processing aids are alike in
- their balance of properties or efficiencies under
different operating conditions. The composition,
structure and/or staging, molecular weight, and
concentration of the processing aid in PVC all
contribute to their performance properties.
With the notable exception of poly(alphamethyl-
styrene) processing aids~ processing aids typically are
thermodynamically miscible or compatible with P~C such
; - 2 -
:~:
that when blended at small levels wlth PVC, the
modi~ied PVC exhibits a slngle glass transitlon
temperature (Tg). While the processing aids are
typically compatlble with PVC, they have Tg's that are
much higher than the Tg of PVC. For example, PVC is
relatlvely soft, having a Tg of about 70C, whlle
polymethyl methacrylate type processing aids have Tgs
on the order of about 95C to about 105C. Processlng
aid~q and PVC also exhiblt dlfferences in viscosity
which also makes it difflcult to obtain homogeneous
blend~ of proces~lng aids in PVC. Obtaining well
disper~ed proce~slng aids throughout the PVC matrlx is
desirable ~or aesthetic and physlcal reasons For
instance, if the processing ald is not weli dlspersed
ln PVC, the processing ald partlcles will lump together
forming gels in the PVC. These gels produce a PVC
product having an undesirable, lrregular or bumpy,
appearance. In addltlon, these gels or lumps also act
as stress concentratlon points ln the PVC promoting
~ fracture initiation and propagation and reducing the
lmpact resistance of PVC.
Improvements in the dispersion of processlng aids
in PVC have been attempted by modifying the proce~sing
conditions to break down the~e gels or by modifying the
structure of the processing ald polymer itself. Higher
shearlng conditions durlng processing have been used to
attempt to improve the dlsperslon of processing aids in
PVC, however, these higher shear condition~ reduce the
output of PVC product that can be achleved. In
3 addltion, attempts to break down the gels, by applylng
more worklng energy to the modified PVC elther by
increasing the internal friction temperature or
shearing condltions by reducing the operating
temperature of the machinery~ have also been attempted
but have been found to be less than completely
~'
, - ,
~i;36~
adequate. Other attempts to modify the composltlon
and/or structure o~ the processlng ald lt~el~, for
example, by formulating ~ multi-~tage proces3ing ald
where the first stage has a Tg equal to or le3~ than
60C and where the amount of the ~lrst stage 18 equal
to or le~s than 25 percent by weight of the total
processlng ald (U.S. Patent 3,833,686) have also been
developed.
DeRplte the wide recognltion of the problem o~
dlspersing proce~sing aids in PVC, no generally
adequate solutlon for dispersing processing aids, that
otherwise exhlbit poor dlsper~ion or lead to a hiBh
level of gel~ in PVC, ha~ been available. -
It is, there~ore~ an obJect o~ this lnventlon to - -
provlde an improved processlng ald composltion that ls
well dispersed ln PVC reducing the tendency of the
processlng ald to ~orm gels in the modlfied PVC.
U.SO Patent No. 4,440,905 entltled Dunkelspersers
i8 believed to be most relevant to the present
lnvention. ~hls patent 13 dlrected to the use of
dlspersant "dunkelsperser" polymer~ to dl~perse
elastomeric impact modifiers in rlgld thermopla~tic
matrlx polymers including PVC. Elastomeric impact
modl~lers are structurally dl~ferent from, and ~unction
quite dlf~erentlg ln PYC than, proces~lng aids.
Elastomerlc impact modiflers are u~ually core-shell or
multlple stage rubbery polymers such a~ methacrylate-
butadlene-styrene (MBS), acrylonltrile-butadiene-
styrene (ABS) and others such as ~or example those
3 descrlbed in U.S. Patents 2,802,809, 2,943,074,
3~251~904J 3~678,133, 3,793,402 and 3,899,547; or
llnear or crosslinked, ~lngle ctage rubbery polymers
such as polybutadiene, butadiene/styrene acrylonitrlle,
llnear ethylene-propylene copolymers; segmented block
copolymer~ such as butanediol-polytetrameth~lene
~, ,' ' , i ~
6~
etherdiol terephthalate ester; or polymers modlfied to
impart elastomeric behavior ~uch as chlorlnated
polyethylene. Other examples of elastomeric lmpact
modifiers are disclosed in U.S Patent 4,440,905.
Impact modlfiers are synthesized to be
elastomeric-ba~ed toughening agents for
thermoplastics. They are insoluble in thermoplastics
and their function can be analogized to the actlon of
rubber balls suspended in a polymer matrix. When
impact modifiers are added to PVC a two phase system,
exhibiting multiple glass transition temperatures~ is
formed. In order to obtain uniform toughness and 5
impact efficiency Por the modified thermoplastic
polymer, these lmpact modifiers, or rubbery spheres,
must be uniformly distributed throughout the polymer
; matrix. Because of the dlfferent criterla requlred to
synthesize impact modifier compositions, and the
different mechanlsm by which impact modiflers function
in thermoplastics compared to processing aids, lt was
completely unexpected to those in the art of PVC
additl~es that "dunkelsperser" polymers could be useful
as dispersion aid polymers in combinatlon with
conventional processing aids for PVC.
SUMMARY OF THE INVENTION
Broadly, the lmproved processing aid compositions
of the invention are blends of conventlonal PVC
processing aid polymers (a) and di~perslon aid polyme-rs
(b), and more partlcularly the lnvention is directed to
lmproved processing ald compositions where the
processing aid polymers (a) are formed from methyl
methacrylate and from O to 50 weight percent of a (Cl-
C4 alkyl)-acrylate, and where the dlspersion ald
polymers (b) are homopolymers or copolymers ~ormed from
at lea~t 50 welght percent of one or more of the
followlng monomers: (Cl-C8 alkyl)-acrylates, (C~-Cg
cycloalkyl)-acrylates, ethylene, propylene,
- 5 -
' `~'`'1
?`~.,5
. ' ' .
.., . i
:
`- ~25i3Çi~
vinylacetate and butadlene, and where the welght ratio
of processing ald polymer (a) to dlspersion ald polymer
(b) i8 ~rom 39~5 to ~.5 ~o 90 to 10, and preferably
from 99 to 1 to 95 to 5; the remainder of the monomers of said
copolymers being methacrylate and/or styrene monomPrs.
The lnventlon al~o lc dlrectsd to PVC compositions
containing the lmproved processlng ald composltions,
and to method~ for for~ulatlng the lmproved processlng
ald and modlfled PVC compositlons.
. DETAILED DESCRIPTION OF THE INVENTION
The processlng ald polymer (a), that ls dispersed
in PVC by the dlsperslon ald polymers (b), may be a
conventlonal slngle or multlple stage polymer as
disclosed ln U.S. Patent 3,833,686 of R.J. Grochowski
et al., issued Sep~ember 3, 1974r or as disclosed in British
Patents 1,511,683 and 981,116.
The dlsperslon ald polymer (b) is a homopolymer or
copolymer formed from at least 50 welght percent o~ one
` or more of the following monomers: (Cl-C8 alkyl)-
acrylates, (C6-Cg cycloalkyl)-acrylates, ethylene,
; propylene, vlnylacetate and butadlene. Pre~erably, the
dispersion aid polymer (b) is one o~ the ~ollowing
polymers: poly(butyl acrylate), poly(ethyl acrylate),
polybutadiene, poly(ethyl acrylate/styrene),
poly(butylacrylate/styrene), poly(butyl acrylate/methyl
methacrylate), poly(ethylacrylate/butyl methacrylate) J
poly(butadlene/styrene) and poly(butylacrylate/
styrene/methyl methacrylate). These polymers are
prepared ~rom less than 50 welght percent methacrylate
3 and/or styrene monomer. Other suitable dispersion
polymers (b) include poly(vinylacetate) and
poly(ethylene/vinylacetate).
The molecular welght range o~ suitable disperslon
aid polymers (b) is wlde, ranging from about 15,000 to
about 100,000 weight average molecular welght. The
dispersion aid polymers (b) may be cros~linked and/or
graft llnked, preferably to a maxlmum extent of 5
i ~ - 6 -
percent by weight crosslinker or graft-linker units.
This crosslinking and/or graft-linking makes the deter-
mination of the molecular weight of the final
dispersion aid polymer (b) difficult.
The dispersion aid polymer (b) is generally a
single stage polymer, but it may be a multiple stage
polymer. When the dispersion aid polymer (b) is a
multiple stage polymer, the overall monomer composition
used to form the polymer and the composition of the
outermost stage must conform to the composition
parameters specified above, namely that these stages
are formed from less than 50 weight percent
methacrylate and/or styrene monomer, even if earlier
stages do not so conYorm. The dispersion aid polymer
(b) should not be confused with any polymer that might
; adventitiously be formed during the preparation of a
multiple stage processlng aid polymer (a)~ since such
an adventitious polymer would not function as a
dispersion aid polymer (b) in the invention.
The dispersion aid polymer (b) is intimately
blended with the processing aid polymer (a) to form the
improved processing aid composition of the invention.
Any method of making a very thorough, intimate mixture
of dispersion aid polymer (b) and processing aid
polymer (a) is sultable, however, simple admixture o~ a
polymeric processing aid powder and a dispersion aid
` polymer will typically be insu~icient unless intimate
~i thorough mixing is achieved. One metho~ of forming the
; improved processing aid compositions of the invention
is to form the dlspersion aid polymer (b) by emulsion
polymerizing the dispersion aid monomers in the
presence of a latex of the processing aid polymer (a)
also havlng been formed by emulsion polymerization.
The presently preferred method is to separately prepare
emulsions of processing aid polymer (a) and dispersion
` aid (b), mix the emulsions together, and then coisolate
,
-- 7 --
.
.
' ~
the two polymers as by spray drying or coagulation.
Spray Drying, An Introductlon to Principles,
Operational Practices, and Applications, K. Masters,
CRC Press, Cleveland, Ohio (1972), describes spray
drying in detail. Coagulation or salting out the
stabllizing surface active agent from the emulsion by
slowly adding the polymer emulsion to, for example,
twice its volume o~ electrolyte solution containing any
one of the ~ollowing salts and/or acids such as NaCl,
,10 KCl, CaCl2, Na2SO4, MgSO4, acetic acid, oxalic acid,
HCl, HNO3, H2SO4 and H3PO4 can be used. The polymers
may then be separated by filtration, washed several
times with fresh water to remove excess electrolyte,
and drled.
The processlng aid polymer (a) and dispersion aid
polymer (b) can also be isolated from the emulsion
mixture by evaporation or ~reeze drying.
When following the preferred preparation and
isolation methods, it is important that the two
emulsions be compatible so that they will not
precipitate prior to the coisolation, or pre~erably the
coagulation, step. For instance, the surfactants used
to prepare the t~o emulsions should be the same or of
similar type, i.e. o~ the same ionic ~pecies and of
similar water solubility or hydrophilic-lipophilic
balance.
The welght ratio of the processing aid polymer (a)
~ to the dispersion aid polymer (b) ranges from 99.5 to
; 0.5 to 90 to 10, and pre~erably from 99 to 1 to 95 to
3 5. Most preferably the weight ratio of the processing
aid (a) to dispersion aid polymer (b) ranges ~rom about
98 to 2 to about 96 to 4.
The vinylchlorlde polymers, to be modi~ied using
the improved processing aid compositions (a plus b) of
the invention, include polyvinylchloride and copolymers
~ormed from at least 50 weight percent vinylchloride
-- 8 --
~3~
., ~
monomer and less than or equal to 50 weight percent o~
at least one other monomer such as vlnylacetate and/or
ethylvinylacetate.
The weight ratio o~ the vinylchloride polymer to
the lmproved processing aid composition may be the same
aæ currently used with vinylchlorlde polymers and
conventional processing alds. Normally this welght
ratio ranges ~rom 90 to 10 to 99.5 to 0.5 vlnylchlorlde
polymer to improved processing aid polymer composition,
and more typically ~rom g5 to 5 to 99 to 1 by welght.
Other standard addltlves may be used to make up
the vinylchloride polymer formulation. For example,
impact modi~iers, colorants, pigments, plasticizers,
stabilizers and lubricants may al~o be added to the
formulatlon.
A~ter the PVC formulatlon is prepared, the
formulation may be processed by standard methods such
as blow moldlng, calendering, inJectlon molding and
extruslon molding to ~orm a ~ubstantially gel ~ree
acticle.
Some preferred embodiment~ o~ the lnvention are
provlded in the illustrative examples that follow.
These examples are intended to illustrate the invention
and should not be construed as limltlng the scope o~
the lnventlon. Comparatlve tests are also provided
utllizing conventional processing aids and compounds
that were lnitially thought to be potentially sultable
as dispersion ald polymers tb). The3e examples clearly
show that some o~ these polymers ~all the
dispersabllity rating test and do not, there~ore, ~all
within the scope o~ the lnvention.
This dlsper abllity ratlng test involved the
preparation of a PVC masterbatch containing
conventional addltives. Two parts of conventlonal
processing aid (a) was added to the PVC masterbatch and
mill-stretched control str~p3 were prepared. A rating
o~ 100 was set as belng equal to a control strip that
_ 9 _
3~
wa~ completely unsultable because it contained many
undispersed particles (gels). It was, however, also
found later in the experiments that the PVC masterbatch
plus 2 parts processing aid (a) could actually result
ln even a less sultably dlspersed (more gels) mill-
stretched strip than the inltial strlps used as the
control ~or examples 1 16. Examples 17-19 compare the
effect of two improved processing ald composition~ of
the in~ention ~or dispersing the processing aid polymer
(a) in the second PVC control formulation having a
dispersability rating greater than 100.
The following presents a general procedure used to
prepare the dlsperslon aid polymers (b) and the PVC
master batch. All parts and percentages are by weight
unless otherwi~e indicated.
Dis~ersion Ald Polymer
Dlspersion aid polymers (b) were prepared in an
aqueous emulsion uslng the following lngredlents and
procedure.
Charges ~ Parts
A - Delonized water at PH greater than 7 u~lng a base 397.5
B - Sodium lauryl ~ulfate (SLS) or sodium stearate 0.26
Bl - Sodium lauryl 3ulfate (SLS) or sodlum stearate 1.49
C - Moncmer(s) to fonn dispe~ion aid polymer (b) 212.6
D - t-dodecyl mercaptan as chain transfer agent or varied
butylene glYCol dlacrylate (B~A) as
difunctlonal mDno~er
E - Potassium persul~ate (KPS) in water as free 1.1
radical initiator
Ihe theoretical solld~ con~ent was calculated to be 32.4%
Prodedure
The delonized water (A) was charged to a one liter
Pour-neck flask fitted with a stirrer, thermometer,
nitrogen inlet and condenser. The water was heated to
65C water and stlrred for lO minutes. me KPS
initiator (E~ was then added followed by 15% of the
.~
-- 10 --
.
~2~
monomer(s) (C) and chain transfer agent and/or BDA
difunctional monomer (D), and the temperature was
maintained at 65C until an exotherm was observed.
At thls point, the second emulsifier charge (Bl)
was added followed by the gradual addition of the
balance of the monomer(s) C and chain transfer agent
and/or BDA difunctional monomer (D) over a one hour
period. After the completion of the addition of the
monomer(s), and chain transfer and/or difunctional
monomer, the batch was maintained at 65C for 15
minutes and then cooled to room temperature.
PVC Masterbatch
A PVC masterbatch formulation without the
processing aid composition of the invention was
prepared from the following ingredients:
Parts
PVC (K-58) Resin 100
Sulfur-c-ontaining organic tin stabilizer 2.0
Plastlcizer-dioctylphthalate (DOP) 5.0
Lubricant System:
Stearic acid 1.0
and Rohm and Haas Company Acryloid~ K-175 3.0
PVC Plus Processin~ Aid
Two parts of conventional proces ing aid and 2
parts o~ the improved processing aid compositions of
the invention were separately added as powders to PVC
masterbatch formulations and mixed homogeneously in a
high intensity Prodex-Henschel blender to form the
final PVC plus processlng aid samples.
Each final formulation was milled on a two-roll
Schwabenthan mill having two chrome polished rolls.
The dimenslon of the rolls are 35 centimeters in length
(30 centimeters in working length) and 15 centimeters
in diameter. The two-roll mill was run at a
temperature of 190C and at a speed of 26/20 rpm
(front/rear rolls). Once the film was formed on the
:
-- 11 --
~ront roll and after the standard practice of obtaining
a homogeneous film was concluded, ~he mill was stopped
and horizontal strips measuring approximately 4 to 5
centlmeters in width were cut at the full length o~ the
roll, taken ~rom the roll, and stretched immediately to
twice their length U9 ing a gulde o~ the appropriate
length. Each stip was held in the stretched position
until cool.
Each milled and stretched strip was rated for the
amount o~ undispersed processing aid particles (gels)
using a rating system of 0 to 100 (except ~or examples
17-19 as explained previously), with 0 being equal to a
strip having no undispersed particles (no gels) and 100
being equal to the standard control (PVC plu~
conventional processing aid (a) only) strip having many
undispersed processlng aid particles (gels). In each
series o~ PVC dispersion evaluations, at least one
sample o~ a conventional processing aid (a) without a
dispersion aid (b) was run as the control. A material,
rated at lO0 or more (control ~or examples 17-19)
contalns an unacceptable number o~ gels. A
dispersability rating of between 40 and 50, based on
lO0 as the control, ls considered to be very gOodg
whereas anything above 70, based on 100, has a
commercially unacceptable number of undlspersed gels.
In examples 17-19, where the control was rated poorer
than 100, a rating o~ 90 or less constituted a-
considerable improvement in processing aid dlspersion.
In order to determine whether a given processing
aid composition is ef~ective to substantially reduce
gel colonies of processing aid (a) in polyvlnylchloride
formulations a reduction of at least about 30 units
~rom a control (rated as 100) is requlred. Pre~erred
dispersion aids (b) gave a reduction of at least 45
units from the control formulation rated as lO0.
- - 12 -
~: .
.::
~3~
, ,~ ,
In the ~ollowing examples, the following
abbreviations are used:
Methyl methacrylate = MMA
Butyl methacrylate = BMA
Styrene = St
Methyl acrylate = MA
Ethyl acrylate = EA
Butyl acrylate . = BA
Butadiene = Bd
o EXAMPLES 1-8
In these examples, reported in Table I, varlous
disperslon aid polymers (b) were prepared in aqueous
emulsion using 4% t-DDM (D) based on monomer(s~ (C)
~ollowing above-described proc0dure. The dispersion
aid emulsion was mlxed with an emulsion of a
conventional methyl methacrylate-ethyl acrylate
processing aid (a) such that the weight ratio of
polymer (b) to polymer (a) was 3 to 97. The mixed
emulsions were then i olated by spray drying. The
ratio of the improved processing aid composition (a
plus b) to PVC in the masterbatch was 2 parts to 100
; parts PVC.
TABLE I
Dispersed
Dispersion Product
Dispe~ion Aid Rating Acceptable/
ExamplePo~r (b) 0-100_ Not acceptable
~ 1 Control PVC plus Conventional 100 Not acceptable
: ~ processing aid (a) only:
no dispersion aid (b)
2 EA 65Acceptable
3 BA 55Acceptable
4 BA/St: 55/45 40Acceptable
BA/St: 70/30 60Acceptable
~ ~ 35 6 MMA 90Not acceptable
: 7 St 85Not acceptable
8 MMA/EA: 90/10 75Not acceptable
, '
~'
~, : - 13 -
:
. . . .
These examples illustrate that methyl methacrylate,
styrene and a 90/10 copolymer of methyl methacrylate
and ethyl acrylate are unacceptable disperslon aid
polymers (b) for use ln the processing aid composition
. of the invention, while polyethyl acrylate, butyl
acrylate and butyl acrylate-styrene copolymers formed
from less than 50 percent styrene, are ef~ective
dispersion aid polymers (b) processing alds in PVC.
EXAMPLES 9 T0 13
These examples explored the relationship between
the composition of the dispersion ald polymer (b) and
its molecular weight. A series of low and high
molecular weight dispersion aid polymers (b) were
prepared using 4% and 0% t-dodecyl mercaptan chain
trans~er agents, respectively. The molecular weight of
the low molecular weight dispersion aid polymers (b)
; ranged from 19,000 to 38,000, while the molecular
weight of the hlgh molecular weight dispersion aid
polymeræ (b) ranged from 137JOOO to 3,890,000. In each
example, the ratio of dispersion aid polymer (b) to
processlng aid polymer (a) was 3 to 97 by weight and
- the processing aid compositions (a plus b) were present
at 2 parts to 100 parts by weight PVC. Dispersability
:. ratings were obtained in accordance with the gensral
procedure as used with examples 1-80 The results are
presented in Table II.
3 0
- 14 -
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a,
Cl~
3 ~ e e ~ ~
~o o o o ~ o
~d ~ ~' ~ I ,o~
~1 ~~ o
g ~_
~D ~
c~ ~ ~ o
H ~ td O v a~ 0
~' ~YU,Y~ ~ ~ ~
O ,~ ,~0~ g
_~
O ~
Q~ ~
oq I
r~ D
C~
~¢CC
~ ~ .
.
. ~ cr~
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The low molecular weight and high molecular welght
polybutylacrylate and polyethylacrylate dispersion aid
polymers (b) (examples 10 and 9) are effective in
dispersing processing aid polymers (a) in PVC. The
effectiveness of these dispersing aids diminished very
slightly wlth decreaslng molecular weight but did not
diminish significantly to the point that they are not
effective dispersion aid polymers (b). Polymethyl
methacrylate and polystyrene are not ef~ective
dispersion aid polymers (b) ~or processing aids at
either high or low molecular weights.
EXAMPLES 14-19
The dispersion aid polymers (b) from examples 2
and 4 were examined to determine the e~fect o~ the
ratio of processing aid polymer (a) to dispersion aid
polymer (b) ln the emulsion mixture on the dispersion
o~ processing aid (a) in PVC.
Exa~ples 14-16 examined a butylacrylate/styrene
(55:45) dispersion aid copolymer (b) in processing aid
compositions where the ratio of (a) to (b) was 98.5 to
1.5 and 97 to 3, respectively. Polymethyl
methacrylate, not a suitable dispersion aid (b) as
indicated by example 6, was also evaluated at these
levels. Examples 17-19 examined an ethylacrylate
dispersion aid polymer a~d a butyl acrylate~styrene
(55:45) dispersion aid copolymer (b), where the ratio
o~ (a) to (b) was 97.5 to 2.5 and 95 to 5. Note,
howéver, that the PVC processlng aid control used in
thls test (Example 17) was much poorer than the
previously prepared controls that had been given a
diæpersability rating o~ 100. The results are shown in
Table III.
- 16 -
~2~36~
~ a) ~ ~
~0 ~ 0
a ~, ~D~
~ a~ J~ ~ 0 a~ a) ~ ~
0 ~ ~ ~ ~ ~
_ 'C O ~ ~ ~ ~
~,~0 cr~ ~ O ~ U~
~ a~ ~
~, r;
~0 ~ ~ ~0
~ ,~ ~ ~ ~ ~ ~ ,n D
o ~ $ ~ D0 ~ ~ ~ ~ $ ~
6q ~ C) C~ Q, O ~ ~ O Q1 R~
HH ~ Z~ . o 09~ 0 ~ ~cC O O
H,1 ~0 c~ ~ Z ~ ~ ~ o c~ d
~ ~ ~ ~ ~' .
E~_~ ~ ~ ~no ~a ~o
0 11~ ' O O O IS~ ~O O U~ Q
. ~ O ~ o ~ ~ ~ N ~ C~
3 p~ ~- ~ l ~
5~
o o
1 0 ~
cq .. ~n
,~
~ ~0~
: ~ ~
¢ cc
o
~: ~
-- 17 --
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Example 15 to the Ba~St (55:45) dispersion aid
copolymer (b) was found to be acceptable as a
dispersion aid polymer ~or processing aid (a) at 1.5%
additive level as well as~at the higher 3% additlve
level. The MMA sample (example 16) is not acceptable
as a dispersion aid polymer (b) at 1.5% or 3% additive
levels.
In examples 17-19 the EA and Ba/St dispersion aid
polymers (b) were found to result in acceptably
; 10 improved dispersion in a very poorly dispersed PVC
control sample having a dispersability rating greater
than 100. The control sample example 17 was much worse
in gel formation than any o~ the previous control
sample~, and rating o~ 90 or less exhibited a
slgnificant improvement even though such absolute
numbers would not have been acceptable with a PVC
control sample rated at 100. The conclusion reached
~rom examples 14-19 is that as the concentration o~
dlspersion aid polymer (b) is increased relative to
processing aid polymer (a), between 1.5 and 5%, the
disperslon of the processing aid was lmproved.
;
~` 30
''
:;
' :
- 18 -
~ ' .
