Note: Descriptions are shown in the official language in which they were submitted.
21 77798
TWG-P-7205-B
THE S?ECIFICATION
STAB~LIZERS FOR HIGH NITRILE
MULTIPOLYMERS
BACKGR~OU~D OF THE INVENTION
Related Application
This patent application is a continuation-in-part of patent
application entitled "Stabilizers for High Nitrile Multipolymers~, USSN
08/~94,833 and ~lled on June 26, 1995, which is a continuation-in-
part of patent application entitled "Stabilizers for
Acrylonitrile/Methac~lonitrile Multipolymers", USSN 08jl71487 and
filed on Oecember 21, 1993.
~ield of the Invention
3 o The present invention relates to a stabilizer composition for
high nitrile multipolymers, in particular an acrylonitrile olefinica!ly
unsaturated multipolymer and the like and a method for stabilizing
the high nitrile multipolymer. More particularly, the invention
relates to the stabilization of an acrylonitrile ole~lnically unsaturated
3 5 multipolymer and the like against thermal degradation, melt
processing conditions and heat discoloration by the inclusion of
maleic acid and its derivatives, salts of maleic acid, maleic
2~ 7779~
-
anhydrides, malean-lides and its salts and maleates and its salts into
the nitrile multipolymer. It is understood that the telm multipolymer
includes copolymers, terpolymers and multimonomer polymers
throughout this specification.
Description of the Prior Art
Nitlile polymers have excellent physical, therrnal and
10 mechanical properties such as barner properties, chemical
resistance, rigidity, heat resistance, UV resistance, moisture
retention and bacteria resistance. Acrylic polymers are high nitrile
polvmers that are desirable in the production of fibrous textiles,
filrns, molded ~?bjects, pack~ging applications and the like.
However, acrylic polymers and other high nitrile
multipolymers having long repeating sequences of the same nitrile
monomer unit, in particular an acrylonitrile monomer unit, are
known to degrade when heated and processed by commercial
methods. The long sequences of nitrile monomer units make the
20 acrylic polymers non-processable without the use of a solvent
l)ecause the polymer degrades at an ever increasing rate above
150C. The acrylic polymer further becomes yellow, orange, red and
eventually black as it degrades.
An acrylonitrile olefinically unsaturated multipolymer is
25 disclosed in USSN 08/387,303 entitled A Process for ,~akiI1g a High
Nitrile Multipolymer Prepared ~rom Acrylonitrile and Olefinically
Unsaturated Monomers." An acrylonitrile/methacrylonitrile
copolymer is ~iscl~sed in USSN 08/150,515 entitled A Process for
Making a Polyrner of Acrylonitrile, Methacrylonitrile and (~lefinically
\
\ 21 7779~
Unsaturated Monomers and a multipolymer of
acrJlonitrile/methacrylonitrile/olef nically unsaturated monomer is
disclosed in USSN 08/14g,8~0 entitled A Process for Making an
Acrylonitrile/ Methacrylonitrile Copolymer.~ The
5 acrylonitrile~methacrylonitrile multipolymers are thermally
processed without the use of ~olvents io yield acrylic fibers.
~owever, the multipolymers are subject to thermal degradation albeit
not as severely as the commercial acrylic fiber polymèr.
Thermoplastic nitrile barrier polymer resins are known in the
10 art and have been described m United St~s Patent Nos. 3, 426,102;
3,586,737 and ~,106,925. These nitrile polymers are known to have
desirable barrier prvperties and chemical resistance. However, these
thermoplastic nitrile polymers while melt-processable are difficult to
process.
It is advantageous to reduce the thermal degradation and
prevent thermal discoloration of high nitrile muitipolymers. There is
a need to readily melt process an acrylonitrile olefinically
unsaturated muitipolymer and the like without thermal degradation,
thermal discoloration and decrease of the viscosity of the high nitrile
2 o multipolymer.
It has been discovered that maleic acid and its derivatives
~E~R ;~ 5
and its salts, maleic anhydrides, maleamides and~ salt's' ar.d
`R ~ ~ ~sl~lq~ r~
maleat~s and ~salts greatly reduce thermal degradation, thermal
discoloration and decrease the viscosity when added o a high nitrile
25 multipolymer, in particular an acrylonitrile olefirlically unsaturated
multipolymer.
U.S. Pat. No. 3,954,913 entitled "Stabilized Nitrile Polymers
and U.S. Pat. No. 3,984,499 entitled ~Therrnally Stable High Nitrile
Resins and Methods for Producing the Same" both assigned to The
21 7779~
Standard Oil Compan3r relate to nitrile poi~-mers, in particular a
Barex~ polymer which is a 75:25 acrylonitrile/methyl acrylate
polymer conta~ning 5% ~o 25% of an elastomeric component. The
patents disclose that the nitIile polymer can be stabilized a~ainst
5 the~rnai discoloration by certaln derivatives of maleic acid, in
particular mono-esters of certain organic polycarboxylic acids. It has
been reported by F`aserforschun~ und Textiltechnik, Volume 21, No.
3 '1970~, that maleic acid and some of its derivatives are useful
inhibitors against thermal discoioration of a nitrile polymer. Further,
10 it states that the complete indifference of the maleic acid esters" for
the stabilization of nitrile polymers. U.S. Patent No. ~,520,847
discloses that naleimides and derivatives thereof are therrmal and
anti-discoloration agents for acrylonitrile polymers and copolymers.
The article and the patents do not disclose nor suggest the use of
5 maleic ac.d and its derivatives, maleic acid and its salts, maleic ,~ 14
~ 6.e ~ c,~/h~u~
anhydrides, rnaleamides and ~ salts, and maleates and itg salts for
the reduction of therrnal degradation and maintenance of melt
processability of a high nitrile polymer.
It is advantageous to reduce the thermal degr~dation and
20 thermal discoloration-of high nitrile multipolymers by the stabilizer
composition of the present invention. The stabili~er composition
reduces melt viscosity and prevents further increases of viscosity of
the high nitrile rnultipolymer during melt processing. Further, the
stabi]izer composition of the present invention reduces crosslinking
25 and molecular weight build-up of the high nitrile multipolymer
during melt processing. Additionally, color development of the nitrile
rmultipolylner duling thermal processing is ret~-ded.
21 7779~
Summ~uy of the Invention
A stabilizer composition for a high nitrile multipolymer
comprises maleic acid and its derivatives, maleic acid and its salts,
5 maleic anh~dride, maleamides and their salts, and rnaleates and
the;r salts. The inclusion of the stabilizer composition in a high
nitrile multipolymer reduces therrnal degradation, discoloration,
molecular weight growth and cross-linking which lead to
intractability and increased melt v;scosity of the multipolymer.
The present invention relates to a composition comprising a
melt processable high nitrile multipolymer said multipolymer being
in admixture with a stabilizer composition comprising maleic acid
and its derivatives, maleic acid and its salts, rnaleic anhydride,
malearnides and their salts, maleates and their salts and
combinations thereof and wherein the stabilizer composition reduces
thermal degradation, reduces the rate of increase of melt viscosity
during therrnal processing and reduces thermal discoloration of the
high nitrile multipolymer.
The process of the present invention produces a thermally
2 o stable nitrile multipolymer, in particular a thermally stable
acrylonitrile olef;nically unsaturated multipolymer. The thermally
stable nitrile multipolyrner may be ~urther processed by spinning into
fibers, injectiorl molding, extrusion, blow extrusion, blow molding
and the like.
2:)
Detailed Description of the Invention
The present invention relates to a stabilizer composition for a
high nitrile multipolymer, in particular an acrylonitrile olefinically
21 7779~
,
unsaturated multipolym.er, &nd a method for stabilizing the high
nitrile mul~ipolymer. The novel stabilizer compositioIl is co.npatible
with the nitrile multipolymer.
The stabili~er composition for addition into the high nitrile
5 multipolymer includes but is not !imited to maleic acid and its
derivatives, maleic acid and its salts, maleic anhydride, malearnides
and their salts, and maleates and their salts. The preferred stabilizer
compositior,s maleates and their salts.
The salts of maleic acid include but are not limited to the
io salts found in Group IIA and IIIB of the Periodic Table of Elements,
salts of organic bases such as amines, and the like. Useful amines
include, but are not limited to, prim~ry, secondary and tertiary alkyl
and aryl amines cont~inin~ Cl through Cl8. Calcium and rnagnesium
are the preferred salts. The salts can be used alone or in
5 combination.
The maleates include but are not limited to esters of maleic
acid of the formula:
2 o }iC====CH
O=C C=O
OR OR
:~5
wherein each R is indepelldently selected from hydrogen ~H), C4 to
Clg alkyl group, ars-l group, alkyl substituted C7 to ~24 ar~l group
and combinations thereof. Exemplary- esters of maleic acid are alkyl
30 half esters of maleic acid, diesters of maleic acid, cetyl maleate, di-
cetyl maleate, octyl maleate, di-octyl m~leate, lauryl maleate, di-
lauryl maleate, butyl maleate, di-butyl maleate, hexadecyl maleate,
2 1 77798
di-hexadecyl maleate, 2-ethylhexyl maleate, di-2-ethylhexyl maleate,
phenyl maleate, di-phenyl maleate, tridecyl maleate, di-tridecyl
maleate, octadec:yl maleate, di-octadecyl maleate and tne like. The
preferred maleates are lauryl maleate, tridecyl maleate, octadecyl
5 maleate, and hexadecyl maleate.
The salts of maleates include, but are not limited to, the
salts found in Group ILA and IIIB of the Periodic Table of Elements,
salts of organic bases such as amines and the like. Use~ul amines
include, but are not limited to, plimar y, secondary, and tertiary alkyl
0 and aryl amines c ontaining C, through (~l~. T~le prefcrred salts are
calcium and magnesium. The salts can be used alone or in
combination.
The maleamides include, but are nct limited to, maleic acid
monoamide of the fornlula HO-CO-C=C-CO-NH-R and maleic acid
5 diamide of the formula R-NH-CO-C-C-CO-NH-R wherein R is
independerltly selected from, hydrogen (H), C4 to Cl~ alkyl group, aryl
group, alkyl substituted C7 to C2~ aryl group and combinations
thereof. The maleamides include mono-alkyl amides of maleic acid,
di-alkyl amides of maleic acid, mono-aryl amides of maleic acid, di-
20 arylamides of maleic acid and the like. Exemplary maleamides arecetyl maleamide, di-cetyl maleamide, octyl maleamide, di-octyl
maleamide, lauryl maleamide, di-lauryl maleamide, butyl maleamide,
di-butyl maleamide, hexadecyl maleamide, di-hexadecyl maieamide,
2-et'nylhe.Yyl maieamide, di-2-ethylhexyl maleamide, phenyl
25 maleamide, di-phenyl maleamide, tridecyl maleamide, di-tridecyl
maleamide, octadecyl maleamide, di-octadecyl rnalea~nide and the
like.
The salts of the rnaleimides include, but are not limited to,
the salts found in Group IIA and IIIB of The Periodic Table of
2 ~ 77798
ElemeIllS, salts OI organic bases such as ~nines, and the like.
Useful amines include, but are not limited to, primary, secondary,
tertiary alkyl and aryl arnines containing Cl through Cl8. The
preferred salts are calcium and magnesium. The salts can be used
5 alone or in combinations.
The stabilizer composition can be used alone or in
combination. The stabilizer composition can also be used with other
additiYes such as plasticizers, pigments, anti-oxidants, fillers, dyes,
delustrants and the like depending on the properties desired to
10 impart to the high nitrile multipolyrner.
The stabilizer composition of the present invention is
effective at low concentrations. The stabilizer composition is added
to the high nitrile multipolymer in the range of about ~.1% to about
10% by weight, preferably about 0.2% to about 5% and most
preferably about 0.3% to about 3% by weight of the nitrile
multipolymer.
The stabilizer composition is a liquid or a solid and~ may be
added to a nitrile multipolymer as a powder, a liquid, an emulsion, or
a solution. The stabilizer composition of the present invention is
2 o typic~lly added to the high nitrile multipolymer subsequent to the
polymerization reaction. For example, the scabilizer composition, as
an emulsion in water, may be added to the high nitrile multipolymer
emulsion latex or suspension slurry prior to the isolation of the
multipolymer, i.e. the coagulation step and subsequent: processing.
25 The stabilizer composition, as a powder, a liquid, a solution, or an
emulsion may be added by dry blending with the isolated
multipolymer strands or powder and the resulting blends can be
pelletized and/or extruded into ~lbers, sheets or other shapes.
21 77798
E~emplaly high nitrile multipolymers are a nitrile
multipolymer comprising an acrylonitriie rmonomer and one or more
ole~lnically unsaturated monomers that are polymerized to produce a
mel~ processable acrylonitrile olefinically unsaturated multipoiymer.
The olefinic~ly unsaturated monomer employed is any olefinically
unsaturated monomer with a C=C double bond polymerizable with
an acIylonitrile monomer.
The olefirlica]ly unsaturated monomer includes but is not
limited to acrylates and their derivatives, methacrylates and their
derivatives, acrylamide and its derivatives, methacrylamide and its
deAvatives, vinyl esters, vinyl ethers, vinyl amides, vinyl ketol~es,
styrene and its derivatives, halogen containing monomers, ionic
monomers, acid containing monomers, base containing monomers,
olefins and the like. The olefinically unsaturated monomer can be
one or more monomers from one or more groups of the olefinically
unsaturated monomers. Thus, there can be more than one
olefinically unsaturated monomer polymerized with the acrylontrile
monomer.
The acrylates include but are not limited to C1 to C12 alkyl,
alyl and cyclic acrylates such as methyl acrylate, ethyl acrylate,
phenyl ac~ylate, butyl acrylate, isobornyl acrylate and 2-ethylhe~yl
acrylate and functional derivatives of the acrylates such as 2-
hydroxyethyl acrylate, 2-chloroethyl acrylate and the like. The
preferred acrylates are methyl acrylate and ethyl acrvlate.
The methacrylates include but are not lirnited to Cl to C12
alkyl~ aryl and cyclic methacrylates such as methyl methacrylate,
ethyl methacrylate, phenyl methacrylate, butyl methacrylate,
isobornyl methacrylate and 2-ethylhexyl methacrylate and functional
deri~ati~-e3 of the methacrylates such as 2-hydroxyethyl
21 77798
methacrylate, 2-chloroethyl methacrylate and the like. The pre~erred
methacrylate is rnethyl methacrylate. The methacrJlate derivatives
include methacrylonitrile.
The acrylamides and methacrylamides and each of their N-
5 substituted alkyl and aryl derivatives include but are not limited toacrylamide, methacrylamides, N-methyl acrylamide, N, N-dimethyl
acrylamide and the like.
The vinyl esters include but are not limited to vinyl acetate,
propionate, butyrate and the like. The preferred vinyl ester is vinyl
0 acetate.
The vinyl ethers include but are not limited to C1 to C8 vinyl
ethers such as ethyl vinyl ether, butyl vinyl ether and the like.
The vinyl amides include but are not limited to vinyl
pyrrolidone and the like.
The vinyl ketones include but are not limited to C1 to C8
vinyl ketones such as ethyl vinyl ketone, buty' vinyl ketone and the
like.
The styrenes include but are not limited to styrene, indene
and a styrene of the formula
~CA=CI~
/ B
'O
\fc
wherein each of A, B, C, and D is independently selected from
hydrogen (H) and C1 to C4 alkyl group for exarnple methylstyrenes,
25 substituted styrenes, multiply-substituted styrenes and the like.
2~ 77798
The halogen containing monome. s include but are not
limited to vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene
chloride, vinylidene bromide, vinylidene fluoride, halogen substituted
propylene monomers and the like. The preferred halogen containing
rnonomers are vinyl bromide and vinylidene chloride.
The ionic monomers-include but are not limited to sodium
vinyl suifonate, sodium styrene sulfonate, sodium methallyl
sulfonate, sodium acrylate, sodium methacrylate and the like. The
preferred ionic monormers are sodium vinyl sulfonate, sodium styrene
o sulfonate and sodium methallyl sulfonate.
The acid containing monomers include but are not limited to
acrylic acid, methacrylic acid, vinyl sulfonic acid, itaconic acid,
styrene sulfonic acid and the like. The preferred acid containing
monomers are itaconic acid, styrene sulfonic acid and vinyl sulfonic
acid.
The base containing monomers include but are not limited to
vinyl pyridine, 2-aminoethyl-N-acrylamide, 3-aminopropyl-N-
acrylamide, 2-aminoethyl acrylate, 2-aminoethyl methacrylate and
the like.
2c The olefins include but are not limited to isoprene,
butadiene, C2 to C8 straight chain and branched alpha-olefins such
as propylene, ethylene, isobutylene, diisobutylene, l-butene and the
like. ~he preferred olefins are isobutylene, ethylene and propylene.
Examples of a high nitrile multipolymer include but are not
limited to acrylonitrile olefinicaliy unsaturated multipolymer,
acrylonitrile/methacrylonitrile/olefinically unsaturated multipolymer,
acrylonitrile/methacrylonitrile multipolymer and the like. The
preferred high nitrile multipolymer is an acrylonitrile olefinically
unsaturated multipolymer.
21 77798
Exemplary methods to make acrylonitrile olefinically
unsaturated multipolymer are described in USSN 08/387,303
entitled ~A Process for Makin~ a High Nitrile Multipolymer Prepared
Fro~n Acrylonitrile and Oiefinically Unsaturated Monomers", an
5 acrylonitrile/mel:hacrylonitrile multipolymer is described in USPN
5,106,~25 entitled "Preparation of Melt-Processable
Acrylonitrile/Methacrylonitrile Copolymers~, and USSN 08/149,880
entitled ~A Process for Making an Acrylonitrile/Methacrylonitrile
CopolymeP and an acrylonitrile/methacrylonitrile/olefinically
0 unsaturated multipolymer is described in US3N 08/150,515 entitled
A Process for Making a Polymer of Acrylonitrile, Methacrylonitrile
and Olefinically Unsaturated Monomers. All four applications are
assigned to The Standard Oil Company and incorporateA herein.
The nitrile multipolymer can be prepared by any known
method such as an emulsion, a solution, a suspension or in
continuous addition bulk process. The polymerization process is
generally carried out as an aqueous emulsion or suspension process
in the presence of a multimonomer feed mixture of an acrylonitrile
monomer and an olefinically unsaturated monomer; a surfactant or
20 suspending aid; optionally a molecular weight modifier; and a free
radical initiator at a temperature in the range of about 40C to 120C
in the substantial absence Or molecular oxygen. The acrylonitrile
olefinically unsaturated mu]timonomer feed mixture contains about
95% by weight to about 20% by weight aclylonitrile monomer, 80%
by weight to about 5% by weight olefinically unsaturated monomer
The polymerization process is carried out by continuous or
incrernental addition of each of the reactants.
The reaction is continued until po]ymerization has proceeded
to the desired extent, generally from about 40% to about 99%
J~
21 77798
con-rersiQn and prefer~bly from about 70% ~o about 95% conversion.
The high nitrile multipolymer generally contains ~0% by weight to
about 95% by weight polymerized acrylonitrile and about 5% by
~,veight to about 50% by weight polymerized olefinicaliy unsaturated
5 monomer.
At the conclusion of the polymerization reaction the
acrylonitrile olefinically unsaturated multipolymer is isolated as a
slurry, or a latex. Any known technique may be used to isolate the
acrylonitrile olefinically unsaturated multipolymer such as crumb
o coagulation, spraying the solution of the multipolymer into a heated
and/or evacuated chamber to remove the water vapors, stripping,
filtration, centrifugation and the like.
The high nitrile multipolymer has reduced thermal
degradation, reduced thermal discoloration and exhibited less "ELr
viscosity increase in subsequent thermal processing steps due to the
presence of the stabilizer composition in the high nitrile
multipolymer.
The high nitrile multipolymer with the stabilizer composition
may be prosessed into a wide variety of useful articles by thermal
20 melt spinning, extrusion in the absence of solvent and in the absence
of water, injection molding, calendering, vacuum forming, milling,
molding, drawing, blowing and the like. The use of the stabilizer
reduces thermal degradation, discoloration, cross-linking and melt
viscosity increase of the nitrile multipolymer products during the
25 thermoprocessing of the nitrile multipolymer.
21 7779~
SPECIFIC EMBODIMENTS
The following examples demonstrate the process and
5 advantages of the present invention.
Multipolymer r~e~alation
Equipment
A 50 gallon circulating hot water jacketed stainless steel
reactor was equipped with a reflux condenser,
thermocouple/controller, a turbine agitator, nitrogen gas inlet line,
vacuum line, and two monomer feed stream pumps. The two
15 monomer feed mixtures were metered, as separate single solutions,
by constant feed pumps.
Procedure
2 o The reactor was initially charged with about 293 lbs. of
distilled water, about 2.75 lbs. of Rhofac RE-610, about 0.85 lbs. of
N-octyl mercaptan, about 7.04 lbs. of acrylonitrile monomer and
about 2.96 lbs. of methacrylonitrile monomer. The reactor was then
purged with nitrogen and heated to about 60C. After temperature
was obtained, a slurry containing 0.47 lbs. of the initiator Vazo 52,
about two lbs. of water and about 0.25 lbs. of Rhofac RE-6 10 was
added along with two separate monomer feed streams. The first
monomer feed was composed of about 70.4 lbs. of acrylonitrile and
about 29.6 lbs. of methacrylonitrile and fed to the reactor at a
i4
21 77798
uniforrm rate over a period of about 270 minutes. The second
monomer ~eed was pure methacrylonitrile-which was fed to the
reactor at about 0.0222 lbs/min. for about the first 90 minutes, at
about 0.0356 lbs/min. from about 90 to about 180 minutes and
finally at a rate of 0.113 lbs./min. for about 180 to about 270
minutes. During the course of the reaction, about 1.19 lbs of N-octyl
mercaptan was added at about 90 minutes and at about 180
minutes.
At the end of the reaction (about 270 minutes) the reaction
o was stripped of unreacted monomer by vacuum stripping at about
60C for about three hours. The latex was then coagulated with
alum solution at about 81C to about 85C and washed with water at
about 75C, and dried. The result was a course, free flowing, white
polymer powder, designated polymer A. The multipolymer
composition of A was 54%(wt.) acrylonitrile and 46%(wt.)
methacrylonitrile with a molecular weight of 143,000.
Preparation of Mono Esters of Maleic Acid
2 o Maleate monoesters were prepared by reacting equal molar
quantities of an alcohol and maleic anhydride under anhydrous
conditions. For example, monolauryl maleate was prepared by
reacting about 5.27 moles of lauryl alcohol (l-dodecanol), with about
5.27 moles of maleic anhydride. The alcohol was melted in about a
50C air oven, weighed, and poured into a jacketed glass 2 liter
reactor which had been preheated to about 50C. The crushed
maleic anhydride was added to the melted alcohol and stirring was
started. The reactor was fitted with a 3" 4-bladed Teflon paddle
rotating at about 350 rpm. The reactor was open to the atmosphere
,_
2 ! 77798
via a port which was fitted with a drying tube containing anhydrous
CaS04. Heat was supplied to the reactor by circulating water, from a
thermostatic~lly controlled bath, through the jacket. After about 25
minutes the temperature of the reaction mixture was increased to
5 about 60C. The appearance of the reactants changed from a slurry
to a hazy liquid to, finally, a clear colorless liquid. After another hour
the temperature was increased to about 70C. Thirty minutes later
the temperature was raised to about 80C~, where it remained for the
balance of the 6 hour total reaction time. The liquid product was
o poured directly from the reactor, without cooling, into a series of
shallow trays, where the liquid was allowed to cool and solidify. The
product was broken up and bottled. About 1516.6g product was
obtained resulting in about a 99.43% recove~r. NMR analysis of the
product showed the product consisted of about 94.2% monolauryl
maleate, about 3.7% dilauryl maleate, about 1.0% maleic acid, and
about 1.1% lauryl alcohol.
Stabilizer Addition Procedure: -
20 Powder Blending:
Finely divided stabilizer is dry blended with polymer powderby any effective mixer. For example, about 1.04 gms. of the stabilizer
that has been ground in a mortar and pestle to a powder is added to
about 50.96 gms of polymer. This powder was blended on a roll-mill
for 3 hours before being subjected to melt processing evaluation.
i6
2 t 777~8
Latex Blendin~:
An aqueous emulsion of the stabilizer is mixed with the
5 polymer latex and the two are co-coagulated to yield an intimately
mixed stabiliær/polymer crumb. A stabilizer emulsion was prepared
by heating a mixture of about 10 gms lauryl maleate and about 2
gms of Dowfax 2A (emulsifier manufactured by Dow Chem. Co.) to
about 60C until homogeneous. To the mixture was added about 88
10 gms. of about 60C water gradually with stirring. The pH of the
mixture was then adjusted to 6 by the addition of ammonium
hydroxide yielding a low viscosity, translucent emulsion. This
stabilizer emulsion can be added in the desired amount to the
polymer latex to achieve the needed level.
Testing Procedure:
Brabender Plasticorder:
The Brabender plasticorder is a low shear melt mixing device
2 o that measures the torque (m-gms~ required to melt stir a molten
- polymer and is manufactured by the Brabender Instrument Co.,
S. Hackensack, NJ. The Brabender Plasticorder is routinely used to
judge the melt processability of Barex~ resins as a quality control
measure. It can easily determine whether a polymer can be melted
25 and processed on normal thermoplastic equipment. Brabender
analyses were run at about 200C with torque readings taken at
about 5 minute intervals to about 30 minutes. This method
measures polymer degradation as a function of time, temperature,
and physical abrading.
/~
2 1 77798
Color:
About 1 gram of multipolymer sample with stabilizer is
5 withdrawn from the Brabender after 10 minutes and again after 30
minutes. Each sample is dissolved in dimethylformamide (DMF) to
make a 5.0% by weight solution in the DMF. Each solution is then
compared to the Gardner Color Standards for Liquid 1953 Series,
made by Gardner Laboratory, Inc., Bethesda, Maryland. The Color
0 Standards for Liquid describes color on a scale of 1 to 18, wherein 1
describes a colorless liquid and 18 describes a beer bottle brown
color.
Stabilizer Evaluation: -
Example 1: Polymer A
Dry blends were prepared from Polymer A and various maleic
20 acid derivatives at the 2% (by weight) level. These blends were
subjected to Brabender plastication and torque measurements at
about 200~C at about 35 rpm. ~mnll ~.nm~ v~ w;lh Law~
~OI~t 1n ~b~ 0 ~nd ~ul 3A .~ ~tcs for ~n~1~3i~r The torque
required to masticate the melt, a measure of melt viscosity, was
2 5 reported in meter-grams (m-gm).
2 1 77798
Table I
Tor~ue (m-gm), 200C
Sample Composition 10 min. 20 min. 30 min.
PolymerA (blank) 2632 2739 3494
~Ialeic acid 2611 :2842 3058
Maleic anhydride 2243 2446 2536
Cetyl maleate 828 782 748
Lauryl maleate 833 773 839
Di-2-ethylhexyl rnaleate 1271 1493 1782
Maleimide 2163 2420 2548
Phenyl maleimide 2207 2295 2278
The above results demonstrate that the addition of the
stabilizer composition in the acrylonitrile/methacrylonitrile
multipolymer reduces the initial melt viscosity and retards its growth
during the melt processing. For instance, lauryl maleate and cetyl
maleate in the nitrile multipolymer show essentially no viscosity
increase in about 30 minutes at about 200''C. The above comparison
of stabilizers demonstrate that the maleates are unexpectedly better
than the maleimides.
Example 2: Polymer B, Mono Maleate Ester Evaluation:
Polymer B of the same AN/MAN composition as Polymer A but
having a molecular weight of 69,000 was dry blended with various
maleate mono esters and subjected to Brabender plastication at
about 200C and about 35 rpm.
Dry blends were prepared from the polymer B and various
maleic acid derivatives at the 2% (by weight) level. These blends were
subjected to Brabender plastication and torque measurements at
2 1 77798
about 200C at about 35 rpm. The torque required to masticate the
melt, a measure of melt viscosity, is reported in meter-grams (m-gm).
TABLE ll
Torque (m-gm), 200C
Sampl~ Composition 10 min. 20 min.30 min.
Polymer B 1883 22722540
2-Ethylhexyl maleate 966 12431780
Nonyl maleate 1570 23273125
Decyl maleate 1046 13492343
Lauryl maleate 731 806 951
Hexadecyl maleate 752 793 995
Octadecyl maleate 827 10691842
Phenyl maleate 1362 17772125
Dodecyl mercaptan maleate 1362 1777 2132
The above results demonstrate that mono maleates
effectively reduce initial melt viscosity and retard viscosity increases
2 o of the nitrile multipolymer during melt processing.
Example 3
A dry polymer comprising about 85% acrylonitrile (AN) and
25 about 15% methyl acrylate (MA) and dry stabilizer were intimately
mixed on a roll mill for about 2 hours at room temperature. The
torque required to masticate the melt, a measure of melt viscosity
was reported in meter-grams (m-gm), color measurements were made
and a maleimide stabilizer was compared to the maleates, and the
30 results are set forth in Table III.
Example 4
3 5 A dry polymer comprising about 85% acrylonitrile and about
15% ethyl acrylate (EA) and dry stabilizer were intimately mixed on a
roll mill for about 2 hours at room temperature. The torque required
to masticate the melt, a measure of melt viscosity was reported in
meter-grams (m-gm) and color measurements were made, and the
4 o results are set forth in Table III.
21 777~8
Example 5
A dry polymer comprising about 85% acrylonitrile, about 7%
5 methyl methacrylate (MMA) and about 7% methyl acrylate and dry
stabilizer were intimately mixed on a roll mill for about 2 hours at
room temperature. The torque required to masticate the melt, a
measure of melt viscosity was reported in meter-grarns ~m-gm) and
color measurements were made, and the results are set forth in Table
10 III.
Example 6
A dry polymer comprising about 75% acrylonitrile and about
25% methyl methacrylate and dry stabilizer were intimately mixed on
a roll mill for about 2 hours at room temperature. The torque
required to masticate the melt, a measure of melt viscosity was
reported in meter-grams (m-gm) and color measurements were made,
2 o and the results are set forth in Table III.
Example 7
A polymer comprising about 85% acrylonitrile and about
15% methyl acrylate was prepared by a continuous feed emulsion
process and recovered as described for polymer A. Dry stabilizer was
added to the polymer and intimately mixed mechanically. The torque
required to masticate the melt, a measure of melt viscosity was
reported in m-gm and color measurements were made. The results
are set forth in Table III and demonstrate lowered final torque values
and improved ~lnal color.
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The above results demonstrate that the inclusion of the
stabilizer into the nitrile multipolymer greatly reduces viscosity of the
nitrile multipolymer during melt processing. Further, the above table
5 demonstrates that the color is better with the inclusion of the
stabilizer into the nitrile multipolymer.
Additionally, Example 3 compares the stabilizer lauryl
maleate to phenyl maleimide. The data demonstrates that the lauryl
maleate is unexpectedly better in color and initial melt torque than
10 the phenyl maleimide. It is unexpected that the lauryl maleate is a
better stabili7er for a high nitrile multipolymer than the phenyl
maleimide.
From the above description and examples of the invention
those skilled in the art will perceive improvements, changes and
modifications in the invention. Such improvements, changes and
modifications within the skill of the art are intended to be covered by
the appended claims.
