U.S. patent application number 13/170611 was filed with the patent office on 2011-12-29 for processes for making cellulose estate/elastomer compositions.
This patent application is currently assigned to EASTMAN CHEMICAL COMPANY. Invention is credited to Soumendra Kumar Basu, Chris Stanley Dagenhart, Jos Simon De Wit, Bradley James Helmer, Marcus David Shelby, Carlo Antony Testa, Matthew Davie Wood.
Application Number | 20110319530 13/170611 |
Document ID | / |
Family ID | 45353124 |
Filed Date | 2011-12-29 |
![](/patent/app/20110319530/US20110319530A1-20111229-C00001.png)
United States Patent
Application |
20110319530 |
Kind Code |
A1 |
Helmer; Bradley James ; et
al. |
December 29, 2011 |
PROCESSES FOR MAKING CELLULOSE ESTATE/ELASTOMER COMPOSITIONS
Abstract
A cellulose ester composition is provided comprising at least
one cellulose ester and at least one additive selected from the
group consisting of a compatibilizer, and a plasticizer. Processes
for producing the cellulose ester composition are also provided. In
another embodiment, a cellulose ester/elastomer composition is
provided comprising at least one elastomer, at least one cellulose
ester; and at least one additive; wherein the additive is at least
one selected from the group consisting of a compatibilizer and a
plasticizer. Processes for producing the cellulose ester/elastomer
composition is also provided as well as articles comprising the
cellulose ester/elastomer composition.
Inventors: |
Helmer; Bradley James;
(Kingsport, TN) ; Basu; Soumendra Kumar; (Johnson
City, TN) ; Wood; Matthew Davie; (Gray, TN) ;
Dagenhart; Chris Stanley; (Johnson City, TN) ; De
Wit; Jos Simon; (Kingsport, TN) ; Testa; Carlo
Antony; (Macclesfield, GB) ; Shelby; Marcus
David; (Fall Branch, TN) |
Assignee: |
EASTMAN CHEMICAL COMPANY
Kingsport
TN
|
Family ID: |
45353124 |
Appl. No.: |
13/170611 |
Filed: |
June 28, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61359582 |
Jun 29, 2010 |
|
|
|
Current U.S.
Class: |
524/37 |
Current CPC
Class: |
C08L 1/14 20130101; C08L
9/06 20130101; C08L 1/10 20130101; C08L 1/22 20130101; C08L 9/06
20130101; C08L 1/10 20130101; C08L 1/20 20130101; C08L 1/24
20130101; C08L 1/16 20130101; C08L 23/08 20130101; C08L 1/18
20130101; C08L 1/12 20130101; C08L 1/32 20130101 |
Class at
Publication: |
524/37 |
International
Class: |
C08L 1/10 20060101
C08L001/10 |
Claims
1. A process for producing a cellulose ester/elastomer composition
comprising mixing at least one cellulose ester, at least one
compatibilizer, and at least one plasticizer.
2. The process according to claim 1 wherein the amount of
compatibilizer ranges from about 1% to about 40% by weight based on
the weight of the cellulose ester.
3. The process according to claim 2 wherein the amount of
compatibilizer ranges from about 5% to about 20% by weight based on
the weight of the cellulose ester.
4. The process according to claim 1 wherein the amount of
plasticizer ranges from about 1% to about 50% by weight based on
the weight of the cellulose ester.
5. The process according to claim 4 wherein the amount of
plasticizer ranges from about 5% to about 35% by weight based on
the weight of the cellulose ester.
Description
RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional Pat.
Appln. No. 61/359,582, filed Jun. 29, 2010, the disclosure of which
is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] This invention belongs to the field of cellulose ester
chemistry, particularly to cellulose esters comprising
compatibilizers and optionally, plasticizers. The invention also
belongs to the field of cellulose ester/elastomer compositions
comprising at least one elastomer and at least one additive wherein
the additive is at least one selected from the group consisting of
a compatibilizer and a plasticizer. Processes for producing the
cellulose ester compositions and the cellulose ester/elastomer
compositions are also provided.
BACKGROUND OF THE INVENTION
[0003] This invention relates to the dispersion of cellulose esters
in elastomers as small particles to improve the mechanical and
physical properties of the elastomer. Polar cellulose esters (CE)
are incompatible with non-polar elastomers. In addition, high
melting cellulose esters do not melt at typical melt processing
temperature of elastomers. These factors make dispersion of
cellulose esters into elastomers difficult via most industrially
utilized melt mixing process. Due to the above problems, cellulose
esters are not an obvious choice as an additive to non-polar
elastomers.
[0004] This invention can overcome these difficulties by using
plasticizers where necessary to help reduce the melt temperature of
cellulose esters and by using compatibilizers to help improve
mixing and compatibility of cellulose esters and elastomers.
Although not wishing to be bound by theory, it is believed that the
compatibilizers used can also improve mechanical and physical
properties of the cellulose ester/elastomer compositions by
improving the interfacial interaction/bonding between the cellulose
ester and the elastomer. These cellulose ester/elastomer
compositions can be used in rubber/elastomeric applications ranging
from tires, hoses, belts, gaskets, automotive parts, and the
like.
[0005] A process of dispersing cellulose esters in elastomers
involves melting or softening cellulose esters so that the
cellulose esters can flow and subsequently break down into small
particles (dispersion) under shear processing. After dispersion,
the cellulose esters can re-solidify upon cooling to room
temperature to reinforce the rubber.
BRIEF SUMMARY OF THE INVENTION
[0006] In one embodiment of the invention, a cellulose ester
composition is provided comprising at least one cellulose ester, at
least one compatibilizer, and optionally, and at least one
plasticizer.
[0007] In another embodiment of the invention, a cellulose
ester/elastomer composition is provided comprising at least one
elastomer, at least one cellulose ester, and at least one additive;
wherein the additive is at least one selected from the group
consisting of a compatibilizer and a plasticizer.
[0008] In another embodiment of the invention, a process for
producing the cellulose ester composition is provided comprising
contacting at least one cellulose ester, at least one
compatibilizer, and optionally, at least one plasticizer.
[0009] In another embodiment of the invention, a process for
producing a cellulose ester/elastomer composition is provided
comprising mixing at least one elastomer, at least one cellulose
ester, and at least one additive for a sufficient time and
temperature to disperse the cellulose ester to produce the
cellulose ester/elastomer composition; wherein the additive is at
least one selected from the group consisting of a compatibilizer
and a plasticizer.
DETAILED DESCRIPTION
[0010] In one embodiment of the invention, a cellulose ester
composition is provided comprising at least one cellulose ester, at
least one compatibilizer, and optionally, at least one
plasticizer.
[0011] The cellulose ester utilized in this invention can be any
that is known in the art. The cellulose esters of the present
invention generally comprise repeating units of the structure:
##STR00001##
wherein R.sup.1, R.sup.2, and R.sup.3 are selected independently
from the group consisting of hydrogen or straight chain alkanoyl
having from 2 to 10 carbon atoms. For cellulose esters, the
substitution level is usually express in terms of degree of
substitution (DS), which is the average number of substitutent per
anhydroglucose unit (AGU). Generally, conventional cellulose
contains three hydroxyl groups in each AGU unit that can be
substituted; therefore DS can have a value between zero and three.
However, low molecular weight cellulose mixed esters can have a
total degree of substitution ranged from about 3.08 to about 3.5.
Native cellulose is a large polysaccharide with a degree of
polymerization from 700-2,000, and thus the assumption that the
maximum DS is 3.0 is approximately correct. However, as the degree
of polymerization is lowered, as in low molecular weight cellulose
mixed esters, the end groups of the polysaccharide backbone become
relatively more significant, thereby resulting in a DS ranging from
about 3.08 to about 3.5. Low molecular weight cellulose mixed
esters are discussed in more detail subsequently in this
disclosure. Because DS is a statistical mean value, a value of 1
does not assure that every AGU has a single substitutent. In some
cases, there can be unsubstituted anhydroglucose units, some with
two and some with three substitutents, and more often than not the
value will be a noninteger. Total DS is defined as the average
number of all of substituents per anhydroglucose unit. The degree
of substitution per AGU can also refer to a particular
substitutent, such as, for example, hydroxyl, acetyl, butyryl, or
propionyl.
[0012] The cellulose ester utilized can be a cellulose triester or
a secondary cellulose ester. Examples of cellulose triesters
include, but are not limited to, cellulose triacetate, cellulose
tripropionate, or cellulose tributyrate. Examples of secondary
cellulose esters include cellulose acetate, cellulose acetate
propionate, and cellulose acetate butyrate. These cellulose esters
are described in U.S. Pat. Nos. 1,698,049; 1,683,347; 1,880,808;
1,880,560; 1,984,147, 2,129,052; and 3,617,201, incorporated herein
by reference in their entirety to the extent that they do not
contradict the statements herein.
[0013] In one embodiment of the invention, the cellulose esters
have at least 2 anhydroglucose rings and typically have between 2
and 5,000 anhydroglucose rings. The number of anhydroglucose units
per molecule is defined as the degree of polymerization (DP) of the
cellulose ester. Cellulose esters typically have an inherent
viscosity (IV) of about 0.2 to about 3.0 deciliters/gram or about 1
to about 1.5, as measured at a temperature of 25.degree. C. for a
0.25 gram sample in 100 ml of a 60/40 by weight solution of
phenol/tetrachloroethane. In another embodiment of the invention,
the total degree of substitution per anhydroglucose unit (DS/AGU)
of the cellulose esters useful herein can range from about 0.5 to
about 2.8, from about 1.5 to about 3.0, and from about 1.7 to about
2.7. Examples of cellulose esters include, but are not limited to,
cellulose acetate, cellulose propionate, cellulose butyrate,
cellulose acetate propionate (CAP), cellulose acetate butyrate
(CAB), cellulose propionate butyrate, and the like. Cellulose
acetate useful herein typically has a DS/AGU for acetyl of about
2.0 to about 2.5. CAP and CAB typically have a total DS/AGU of
about 1.7 to about 2.8.
[0014] Cellulose esters can be produced by any method known in the
art. Examples of processes for producing cellulose esters are
taught in Kirk-Othmer, Encyclopedia of Chemical Technology,
5.sup.th Edition, Vol. 5, Wiley-Interscience, New York (2004), pp.
394-444. Cellulose, the starting material for producing cellulose
esters, can be obtained in different grades and sources such as
from cotton linters, softwood pulp, hardwood pulp, corn fiber and
other agricultural sources, and bacterial cellulose, among
others.
[0015] One method of producing cellulose esters is esterification
of the cellulose by mixing cellulose with the appropriate organic
acids, acid anhydrides, and catalysts. Cellulose is then converted
to a cellulose triester. Ester hydrolysis is then performed by
adding a water-acid mixture to the cellulose triester, which can
then be filtered to remove any gel particles or fibers. Water is
then added to the mixture to precipitate the cellulose ester. The
cellulose ester can then be washed with water to remove reaction
by-products followed by dewatering and drying.
[0016] The cellulose triesters to be hydrolyzed can have three
substitutents selected independently from alkanoyls having from 2
to 10 carbon atoms. Examples of cellulose triesters include
cellulose triacetate, cellulose tripropionate, and cellulose
tributyrate or mixed triesters of cellulose such as cellulose
acetate propionate, and cellulose acetate butyrate. These cellulose
esters can be prepared by a number of methods known to those
skilled in the art. For example, cellulose esters can be prepared
by heterogeneous acylation of cellulose in a mixture of carboxylic
acid and anhydride in the presence of a catalyst such as
H.sub.2SO.sub.4. Cellulose triesters can also be prepared by the
homogeneous acylation of cellulose dissolved in an appropriate
solvent such as LiCl/DMAc or LiCl/NMP.
[0017] Those skilled in the art will understand that the commercial
term of cellulose triesters also encompasses cellulose esters that
are not completely substituted with acyl groups. For example,
cellulose triacetate commercially available from Eastman Chemical
Company, Inc., Kingsport, Tenn., U.S.A., typically has a DS from
about 2.85 to about 2.95.
[0018] After esterification of the cellulose to the triester, part
of the acyl substitutents are removed by hydrolysis or by
alcoholysis to give a secondary cellulose ester. As noted
previously, depending on the particular method employed, the
distribution of the acyl substituents can be random or non-random.
Secondary cellulose esters can also be prepared directly with no
hydrolysis by using a limiting amount of acylating reagent. This
process is particularly useful when the reaction is conducted in a
solvent that will dissolve cellulose. All of these methods yield
cellulose esters that are useful in this invention.
[0019] In one embodiment, the secondary cellulose esters useful in
the present invention have a weight average molecular weight (Mw)
from about 5,000 to about 400,000 as measured by GPC. In a further
embodiment, the Mw is from about 10,000 to about 300,000. In yet
further embodiments, the Mw ranges from about 10,000 to about
250,000; from about 10,000 to about 100,000, and from about 15,000
to about 80,000.
[0020] The most common commercial secondary cellulose esters are
prepared by initial acid catalyzed heterogeneous acylation of
cellulose to form the cellulose triester. After a homogeneous
solution in the corresponding carboxylic acid of the cellulose
triester is obtained, the cellulose triester is then subjected to
hydrolysis until the desired degree of substitution is obtained.
After isolation, a randomly secondary cellulose ester is obtained.
That is, the relative degree of substitution (RDS) at each hydroxyl
is roughly equal.
[0021] In another embodiment of the invention, low molecular weight
mixed cellulose esters can be utilized as disclosed in U.S. patent
application Ser. No. 10/796,176, herein incorporated by reference
to the extent it does not contradict the statements herein. In one
embodiment of the invention, the low molecular weight mixed
cellulose ester has the following properties: a total degree of
substitution per anhydroglucose unit of from about 3.08 to about
3.50, having the following substitutions:
[0022] a degree of substitution per anhydroglucose unit of hydroxyl
of no more than about 0.70,
[0023] a degree of substitution per anhydroglucose unit of
C.sub.3-C.sub.4 esters from about 0.80 to about 1.40, and
[0024] a degree of substitution per anhydroglucose unit of acetyl
of from about 1.20 to about 2.34;
[0025] an inherent viscosity of from about 0.05 to about 0.15 dL/g,
as measured in a 60/40 (wt./wt.) solution of
phenol/tetrachloroethane at 25.degree. C.;
[0026] a number average molecular weight (M.sub.n) of from about
1,000 to about 5,600;
[0027] a weight average molecular weight (M.sub.w) of from about
1,500 to about 10,000; and
[0028] a polydispersity of from about 1.2 to about 3.5.
[0029] In another embodiment of the invention, the low molecular
weight cellulose mixed ester has the following properties:
[0030] a total degree of substitution per anhydroglucose unit of
from about 3.08 to about 3.50, having the following
substitutions:
[0031] a degree of substitution per anhydroglucose unit of hydroxyl
of no more than about 0.70;
[0032] a degree of substitution per anhydroglucose unit of
C.sub.3-C.sub.4 esters from about 1.40 to about 2.45, and
[0033] a degree of substitution per anhydroglucose unit of acetyl
of from about 0.20 to about 0.80;
[0034] an inherent viscosity of from about 0.05 to about 0.15 dL/g,
as measured in a 60/40 (wt./wt.) solution of
phenol/tetrachloroethane at 25.degree. C.;
[0035] a number average molecular weight (M.sub.n) of from about
1,000 to about 5,600;
[0036] a weight average molecular weight (M.sub.w) of from about
1,500 to about 10,000; and
[0037] a polydispersity of from about 1.2 to about 3.5.
[0038] In another embodiment of the invention, the low molecular
weight cellulose mixed ester has the following properties:
[0039] a total degree of substitution per anhydroglucose unit of
from about 3.08 to about 3.50, having the following
substitutions:
[0040] a degree of substitution per anhydroglucose unit of hydroxyl
of no more than about 0.70;
[0041] a degree of substitution per anhydroglucose unit of
C.sub.3-C.sub.4 esters from about 2.11 to about 2.91, and
[0042] a degree of substitution per anhydroglucose unit of acetyl
of from about 0.10 to about 0.50;
[0043] an inherent viscosity of from about 0.05 to about 0.15 dL/g,
as measured in a 60/40 (wt./wt.) solution of
phenol/tetrachloroethane at 25.degree. C.;
[0044] a number average molecular weight (M.sub.n) of from about
1,000 to about 5,600;
[0045] a weight average molecular weight (M.sub.w) of from about
1,500 to about 10,000; and
[0046] a polydispersity of from about 1.2 to about 3.5.
[0047] The cellulose esters useful in the present invention can be
prepared using techniques known in the art and can be commercially
obtained, e.g., from Eastman Chemical Company, Kingsport, Tenn.,
U.S.A.
[0048] The cellulose esters utilized in this invention can also
contain chemical functionality and are described herein as either
derivatized, modified, or functionalized cellulose esters.
Functionalized cellulose esters are produced by reacting the free
hydroxyl groups of cellulose esters with a bifunctional reactant
that has one linking group for grafting to the cellulose ester and
one functional group to provide a new chemical group to the
cellulose ester. Examples of such bifunctional reactants include
succinic anhydride which links through an ester bond and provides
acid functionality; mercaptosilanes which links through
alkoxysilane bonds and provides mercapto functionality; and
isocyanotoethyl methacrylate which links through a urethane bond
and gives methacrylate functionality.
[0049] In one embodiment of the invention, functionalized cellulose
esters are produced by reacting the free hydroxyl groups of the
cellulose esters with a bifunctional reactant producing a cellulose
ester with at least one functional group selected from the group
consisting of unsaturation (double bonds), carboxylic acids,
acetoacetate, acetoacetate imide, mercapto, melamine, and long
alkyl chains.
[0050] Bifunctional reactants to produce cellulose esters
containing unsaturation (double bonds) functionality are described
in U.S. Pat. Nos. 4,839,230, 5,741,901, 5,871,573, 5,981,738,
4,147,603, 4,758,645, and 4,861,629; all of which are incorporated
by reference to the extent they do not contradict the statements
herein. In one embodiment, the cellulose esters containing
unsaturation is produced by reacting a cellulose ester containing
residual hydroxyl groups with an acrylic based compound and
m-isopropyenyl-.alpha.,.alpha.'-dimethylbenzyl isocyanate. The
grafted cellulose ester is a urethane-containing product having
pendant (meth)acrylate and .alpha.-methylstyrene moieties. In
another embodiment, the cellulose esters containing unsaturation is
produced by reacting maleic anhydride and a cellulose ester in the
presence of an alkaline earth metal or ammonium salt of a lower
alkyl monocarboxylic acid catalyst, and at least one saturated
monocarboxylic acid have 2 to 4 carbon atoms. In another
embodiment, the cellulose esters containing unsaturation is
produced from the reaction product of (a) at least one cellulosic
polymer having isocyanate reactive hydroxyl functionality, and (b)
at least one hydroxyl reactive poly(alpha,beta ethyleneically
unsaturated) isocyanate.
[0051] Bifunctional reactants to produce cellulose esters
containing carboxylic acid functionality are described in U.S. Pat.
Nos. 5,384,163, 5,723,151, and 4,758,645; all of which are
incorporated by reference to the extent they do not contradict the
statements herein. In one embodiment, the cellulose esters
containing carboxylic acid functionality is produced by reacting a
cellulose ester and a mono- or di-ester of maleic or furmaric acid,
thereby obtaining a cellulose derivative having double bond
functionality. In another embodiment, the cellulose esters
containing carboxylic acid functionality has a first and second
residue, wherein the first residue is a residue of a cyclic
dicarboxylic acid anhydride and the second residue is a residue of
an oleophilic monocarboxylic acid and/or a residue of a hydrophilic
monocarboxylic acid. In yet another embodiment, the cellulose
esters containing carboxylic acid functionality are cellulose
acetate phthalates, which can be prepared by reacting cellulose
acetate with phthalic anhydride.
[0052] Bifunctional reactants to produce cellulose esters
containing acetoacetate functionality are described in U.S. Pat.
No. 5,292,877; which is incorporated by reference to the extent it
does not contradict the statements herein. In one embodiment, the
cellulose esters containing acetoacetate functionality are produced
by contacting: (i) cellulose; (ii) diketene, an alkyl acetoacetate,
2,2,6, trimethyl-4H 1,3-dioxin-4-one, or a mixture thereof, (iii) a
solubilizing amount of solvent system comprising lithium chloride
plus a carboxamide selected from the group consisting of
1-methyl-2-pyrolidinone, N,N dimethylacetamide, or a mixture
thereof.
[0053] Bifunctional reactants to produce cellulose esters
containing acetoacetate imide functionality are described in U.S.
Pat. No. 6,369,214 which is incorporated by reference to the extent
it does not contradict the statements herein. Cellulose esters
containing acetoacetate imide functionality are the reaction
product of a cellulose ester and at least one acetoacetyl group and
an amine functional compound comprising at least one primary
amine.
[0054] Bifunctional reactants to produce cellulose esters
containing mercapto functionality are described in U.S. Pat. No.
5,082,914; which is incorporated by reference to the extent it does
not contradict the statements herein. In one embodiment of the
invention, the cellulose ester is grafted with a silicon-containing
thiol component which is either commercially available or can be
prepared by procedures known in the art. Examples of
silicon-containing thiol compounds include, but are not limited to,
(3-mercaptopropyl)trimethoxysilane,
(3-mercaptopropyl)-dimethyl-methoxysilane,
(3-mercaptopropyl)dimethoxymethylsilane,
(3-mercaptopropyl)dimethylchlorosilane,
(3-mercaptopropyl)dimethylethoxysilane,
(3-mercaptopropyl)diethyoxymethylsilane, and
(3-mercapto-propyl)triethoxysilane.
[0055] Bifunctional reactants to produce cellulose esters
containing melamine functionality are described in U.S. Pat. No.
5,182,379; which is incorporated by reference to the extent it does
not contradict the statements herein. In one embodiment, the
cellulose esters containing melamine functionality are prepared by
reacting a cellulose ester with a melamine compound to form a
grafted cellulose ester having melamine moieties grafted to the
backbone of the anhydrogluclose rings of the cellulose ester. In
one embodiment, the melamine compound is selected from the group
consisting of methylol ethers of melamine and aminoplast
resins.
[0056] Bifunctional reactants to produce cellulose esters
containing long alkyl chain functionality are described in U.S.
Pat. No. 5,750,677; which is incorporated by reference to the
extent it does not contradict the statements herein. In one
embodiment, the cellulose esters containing long alkyl chain
functionality is produced by reaction of cellulose in a carboxamide
diluents or a urea-based diluents with an acylating reagent using a
titanium-containing specifies. Cellulose esters containing long
alkyl chain functionality can be selected from the group consisting
of cellulose acetate hexanoate, cellulose acetate nonanoate,
cellulose acetate laurate, cellulose palmitate, cellulose acetate
stearate, cellulose nonanoate, cellulose hexanoate, cellulose
hexanoate propionate, and cellulose nonanoate propionate.
[0057] The plasticizer utilized in this invention can be any that
is known in the art that can reduce the melt temperature and/or the
melt viscosity of the cellulose ester. The plasticizer can be
either monomeric or polymeric in structure. In one embodiment, the
plasticizer is at least one selected from the group consisting of a
phosphate plasticizer, benzoate plasticizer, adipate plasticizer, a
phthalate plasticizer, a glycolic acid ester, a citric acid ester
plasticizer and a hydroxyl-functional plasticizer.
[0058] In one embodiment of the invention, the plasticizer can be
selected from at least one of the following: triphenyl phosphate,
tricresyl phosphate, cresyldiphenyl phosphate, octyldiphenyl
phosphate, diphenylbiphenyl phosphate, trioctyl phosphate, tributyl
phosphate, diethyl phthalate, dimethoxyethyl phthalate, dimethyl
phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl
phthalate, butylbenzyl phthalate, dibenzyl phthalate, butyl
phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl
phthalyl ethyl glycolate, triethyl citrate, tri-n-butyl citrate,
acetyltriethyl citrate, acetyl-tri-n-butyl citrate, and acetyl-
tri-n-(2-ethylhexyl) citrate.
[0059] In another embodiment of the invention, the plasticizer can
be selected from at least one of the following: esters comprising:
(i) acid residues comprising one or more residues of: phthalic
acid, adipic acid, trimellitic acid, succinic acid, benzoic acid,
azelaic acid, terephthalic acid, isophthalic acid, butyric acid,
glutaric acid, citric acid or phosphoric acid; and (ii) alcohol
residues comprising one or more residues of an aliphatic,
cycloaliphatic, or aromatic alcohol containing up to about 20
carbon atoms.
[0060] In another embodiment of the invention, the plasticizer can
be selected from at least one of the following: esters comprising:
(i) at least one acid residue selected from the group consisting of
phthalic acid, adipic acid, trimellitic acid, succinic acid,
benzoic acid, azelaic acid, terephthalic acid, isophthalic acid,
butyric acid, glutaric acid, citric acid and phosphoric acid; and
(ii) at least one alcohol residue selected from the group
consisting of aliphatic, cycloaliphatic, and aromatic alcohol
containing up to about 20 carbon atoms.
[0061] In another embodiment of the invention, the plasticizer can
comprise alcohol residues where the alcohol residues is at least
one selected from the following: stearyl alcohol, lauryl alcohol,
phenol, benzyl alcohol, hydroquinone, catechol, resorcinol,
ethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, and
diethylene glycol.
[0062] In another embodiment of the invention, the plasticizer can
be selected from at least one of the following: benzoates,
phthalates, phosphates, arylene-bis(diaryl phosphate), and
isophthalates. In another embodiment, the plasticizer comprises
diethylene glycol dibenzoate, abbreviated herein as "DEGDB".
[0063] In another embodiment of the invention, the plasticizer can
be selected from at least one of the following: aliphatic
polyesters comprising C.sub.2-10 diacid residues, for example,
malonic acid, succinic acid, glutaric acid, adipic acid, pimelic
acid, suberic acid, azelaic acid, and sebacic acid; and C.sub.2-10
diol residues.
[0064] In another embodiment, the plasticizer can comprise diol
residues which can be residues of at least one of the following
C.sub.2-C.sub.10 diols: ethylene glycol, diethylene glycol,
1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol,
1,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol,
1,5-pentanediol, 1,6 hexanediol, 1,5-pentylene glycol, triethylene
glycol, and tetraethylene glycol.
[0065] In another embodiment of the invention, the plasticizer can
include polyglycols, such as, for example, polyethylene glycol,
polypropylene glycol, and polybutylene glycol. These can range from
low molecular weight dimers and trimers to high molecular weight
oligomers and polymers. In one embodiment, the molecular weight of
the polyglycol can range from about 200 to about 2000.
[0066] In another embodiment of the invention, the plasticizer
comprises at least one of the following: Resoflex.RTM. R296
plasticizer, Resoflex.RTM. 804 plastocizer, SHP (sorbitol
hexapropionate), XPP (xylitol pentapropionate), XPA (xylitol
pentaacetate), GPP (glucose pentaacetate), GPA (glucose
pentapropionate) and APP (arabitol pentapropionate).
[0067] In another embodiment of the invention, the plasticizer
comprises one or more of: A) from about 5 to about 95 weight % of a
C.sub.2-C.sub.12 carbohydrate organic ester, wherein the
carbohydrate comprises from about 1 to about 3 monosaccharide
units; and B) from about 5 to about 95 weight % of a
C.sub.2-C.sub.12 polyol ester, wherein the polyol is derived from a
C.sub.5 or C.sub.6 carbohydrate. In one embodiment, the polyol
ester does not comprise or contain a polyol acetate or polyol
acetates.
[0068] In another embodiment, the plasticizer comprises at least
one carbohydrate ester and the carbohydrate portion of the
carbohydrate ester is derived from one or more compounds selected
from the group consisting of glucose, galactose, mannose, xylose,
arabinose, lactose, fructose, sorbose, sucrose, cellobiose,
cellotriose and raffinose.
[0069] In another embodiment of the invention, the plasticizer
comprises at least one carbohydrate ester and the carbohydrate
portion of the carbohydrate ester comprises one or more of
.alpha.-glucose pentaacetate, .beta.-glucose pentaacetate,
.alpha.-glucose pentapropionate, .beta.-glucose pentapropionate,
.alpha.-glucose pentabutyrate and .beta.-glucose pentabutyrate.
[0070] In another embodiment, the plasticizer comprises at least
one carbohydrate ester and the carbohydrate portion of the
carbohydrate ester comprises an .alpha.-anomer, a .beta.-anomer or
a mixture thereof.
[0071] In another embodiment of the invention, the plasticizer can
be a solid, non-crystalline resin. These resins can contain some
amount of aromatic or polar functionality and can lower the melt
viscosity of the cellulose esters. In one embodiment of the
invention, the plasticizer can be a solid, non-crystalline compound
(resin), such as, for example, rosin; hydrogenated rosin;
stabilized rosin, and their monofunctional alcohol esters or polyol
esters; a modified rosin including, but not limited to, maleic- and
phenol-modified rosins and their esters; terpene resins;
phenol-modified terpene resins; coumarin-indene resins; phenolic
resins; alkylphenol-acetylene resins; and phenol-formaldehyde
resins.
[0072] The amount of plasticizer in the cellulose ester composition
can range from about 1 to about 50 weight percent based on the
weight of the cellulose ester. Another range can be from about 5 to
about 35 weight percent based on the weight of the cellulose
ester.
[0073] The compatibilizer can be either a non-reactive
compatibilizer or a reactive compatibilizer. The compatibilizer can
enhance the ability of the cellulose ester to reach a desired small
particle size to improve the dispersion of the cellulose ester into
an elastomer. The compatibilizers used can also improve mechanical
and physical properties of the cellulose ester/elastomer
compositions by improving the interfacial interaction/bonding
between the cellulose ester and the elastomer.
[0074] When non-reactive compatibilizers are utilized, the
compatibilizer contains a first segment that is compatible with the
cellulose ester and a second segment that is compatible with a
nonpolar elastomer. The first segment contains polar functional
groups, which provide compatibility with the cellulose ester,
including, but not limited to, such polar functional groups as
ethers, esters, amides, alcohols, amines, ketones and acetals. The
first segment may consist of oligomers or polymers of the
following: cellulose esters; cellulose ethers; polyoxyalkylene,
such as, polyoxyethylene, polyoxypropylene, polyoxybutylene;
polyglycols, such as, polyethylene glycol, polypropylene glycol,
polybutylene glycol; polyesters, such as, polycaprolactone,
polylactic acid, aliphatic polyesters, aliphatic-aromatic
copolyesters; polyacrylates and polymethacrylates; polyacetals;
polyvinylpyrrolidone; polyvinyl acetate; and polyvinyl alcohol. In
one embodiment, the first segment is polyoxyethylene or polyvinyl
alcohol.
[0075] The second segment is compatible with the nonpolar elastomer
and contains nonpolar groups. The second segment can be either
saturated or unsaturated hydrocarbon groups or contain both
saturated and unsaturated hydrocarbon groups. The second segment
can be an oligomer or a polymer. In one embodiment of the
invention, the second segment of the non-reactive compatibilizer is
selected from the group consisting of polyolefins, polydienes,
polyaromatics, and copolymers. An example of a polyaromatic second
segment is polystyrene. An example of a copolymer second segment is
styrene/butadiene copolymer.
[0076] The first and second segments of the non-reactive
compatibilizers can be in a diblock, triblock, branched or comb
structure. The molecular weight of the non-reactive compatibilizers
can range from about 300 to about 20,000 or from about 500 to about
10,000 or from about 1,000 to about 5,000. The segment ratio of the
non-reactive compatibilizers can range from about 15 to about 85%
polar first segments to about 15 to about 85% nonpolar second
segments.
[0077] Examples of non-reactive compatibilizers include, but are
not limited to, ethoxylated alcohols, ethoxylated alkylphenols,
ethoxylated fatty acids, block polymers of propylene oxide and
ethylene oxide, polyglycerol esters, polysaccharide esters, and
sorbitan esters. Examples of ethoxylated alcohols are
C.sub.11-C.sub.15 secondary alcohol ethoxylates, polyoxyethylene
cetyl ether, polyoxyethylene stearyl ether, and C.sub.12-C.sub.14
natural liner alcohol ethoxylated with ethylene oxide.
C.sub.11-C.sub.15 secondary ethyoxylates can be obtained as Dow
Tergitol.RTM. 15S from the Dow Chemical Company. Polyoxyethlene
cetyl ether and polyoxyethylene stearyl ether can be obtained from
ICI Surfactants under the Brij.RTM. series of products.
C.sub.12-C.sub.14 natural linear alcohol ethoxylated with ethylene
oxide can be obtained from Hoechst Celanese under the Genapol.RTM.
series of products. Examples of ethoxylated alkylphenols include
octylphenoxy poly(ethyleneoxy)ethanol and nonylphenoxy
poly(ethyleneoxy)ethanol. Octylphenoxy poly(ethyleneoxy)ethanol can
be obtained as Igepal.RTM. CA series of products from Rhodia, and
nonylphenoxy poly(ethyleneoxy)ethanol can be obtained as Igepal CO
series of products from Rhodia or as Tergitol.RTM. NP from Dow
Chemical Company. Ethyoxylated fatty acids include
polyethyleneglycol monostearate or monolaruate which can be
obtained from Henkel under the Nopalcol.RTM. series of products.
Block polymers of propylene oxide and ethylene oxide can be
obtained under the Pluronic.RTM. series of products from BASF.
Polyglycerol esters can be obtained from Stepan under the
Drewpol.RTM. series of products. Polysaccharide esters can be
obtained from Henkel under the Glucopon.RTM. series of products,
which are alkyl polyglucosides. Sorbitan esters can be obtained
from ICI under the Tween.RTM. series of products.
[0078] In another embodiment of the invention, the non-reactive
compatibilizers can be synthesized in situ in the cellulose ester
composition or the cellulose ester/elastomer composition by
reacting cellulose ester-compatible compounds with
elastomer-compatible compounds. These compounds can be, for
example, telechelic oligomers, which are defined as prepolymers
capable of entering into further polymerization or other reaction
through their reactive end groups. In one embodiment of the
invention, these in situ compatibilizers can have higher molecular
weight from about 10,000 to about 1,000,000.
[0079] In another embodiment of the invention, the compatibilizer
can be reactive. The reactive compatibilizer comprises a polymer or
oligomer compatible with one component of the composition and
functionality capable of reacting with another component of the
composition. There are two types of reactive compatibilizers. The
first reactive compatibilizer has a hydrocarbon chain that is
compatible with a nonpolar elastomer and also has functionality
capable of reacting with the cellulose ester. Such functional
groups include, but are not limited to, carboxylic acids,
anhydrides, acid chlorides, epoxides, and isocyanates. Specific
examples of this type of reactive compatibilizer include, but are
not limited to: long chain fatty acids, such as, stearic acid
(octadecanoic acid); long chain fatty acid chlorides, such as,
stearoyl chloride (octadecanoyl chloride); long chain fatty acid
anhydrides, such as, stearic anhydride (octadecanoic anhydride);
epoxidized oils and fatty esters; styrene maleic anhydride
copolymers; maleic anhydride grafted polypropylene; copolymers of
maleic anhydride with olefins and/or acrylic esters, e.g.
terpolymers of ethylene, acrylic ester and maleic anhydride; and
copolymers of glycidyl methacrylate with olefins and/or acrylic
esters, e.g. terpolymers of ethylene, acrylic ester, and glycidyl
methacrylate.
[0080] Reactive compatibilizers can be obtained as SMA.RTM. 3000
styrene maleic anhydride copolymer from Sartomer/Cray Valley,
Eastman G-3015.RTM. maleic anhydride grafted polypropylene from
Eastman Chemical Company, Epolene.RTM. E-43 maleic anhydride
grafted polypropylene obtained from Westlake Chemical, Lotader.RTM.
MAH 8200 random terpolymer of ethylene, acrylic ester, and maleic
anhydride obtained from Arkema, Lotader.RTM. GMA AX 8900 random
terpolymer of ethylene, acrylic ester, and glycidyl methacrylate,
and Lotarder.RTM. GMA AX 8840 random terpolymer of ethylene,
acrylic ester, and glycidyl methacrylate.
[0081] The second type of reactive compatibilizer has a polar chain
that is compatible with the cellulose ester and also has
functionality capable of reacting with a nonpolar elastomer.
Examples of these types of reactive compatibilizers include
cellulose esters or polyethylene glycols with olefin or thiol
functionality. Reactive polyethylene glycol compatibilizers with
olefin functionality include, but are not limited to, polyethylene
glycol allyl ether and polyethylene glycol acrylate. An example of
a reactive polyethylene glycol compatibilizer with thiol
functionality includes polyethylene glycol thiol. An example of a
reactive cellulose ester compatibilizer includes mercaptoacetate
cellulose ester.
[0082] The amount of compatibilizer in the cellulose ester
composition can range from about 1 wt % to about 40 wt % or from
about 5 wt % to about 20 wt % based on the weight of the cellulose
ester.
[0083] In another embodiment of this invention, a cellulose
ester/elastomer composition is provided comprising at least one
elastomer, at least one cellulose ester, and at least one additive;
wherein the additive is at least one selected from the group
consisting of at least one plasticizer and at least one
compatibilizer. The cellulose esters, plasticizers, and
compatibilizers have been previously described in this disclosure.
The elastomer in this invention is at least one non-polar elastomer
known in the art. In one embodiment, the non-polar elastomer is
primarily based on hydrocarbon. For example, non-polar elastomers
include, but are not limited to, natural rubber, polybutadiene,
polyisoprene, styrene-butadiene rubber, polyolefins, ethylene
propylene diene monomer (EPDM), and polynorbornene. Examples of
polyolefins include, but are not limited to, polybutylene,
polyisobutylene, and ethylene propylene rubber.
[0084] The amount of cellulose ester in the cellulose
ester/elastomer composition ranges from about 1 to about 50 parts
per hundred rubber (phr) based on the elastomer. Other ranges are
from about 5 to about 30 phr and about 3 to about 30 phr based on
the weight of the elastomer.
[0085] The amount of compatibilizer can range from about 1% to
about 40% by weight based on the weight of the cellulose ester.
Another range is from about 5% to about 20% by weight based on the
weight of the cellulose ester.
[0086] The amount of plasticizer can range from about 1% to about
50% by weight based on the weight of the cellulose ester. Another
range is from about 5% to about 35% by weight based on the weight
of the cellulose ester.
[0087] In another embodiment of the invention, the cellulose
ester/elastomer compositions further comprise at least one
crosslinking/curing agent. Crosslinking/curing agents can be any
that is known in the art. Examples of crosslinking/curing agents
include, but are not limited to, organic peroxides and sulfur.
[0088] In another embodiment of the invention, a process for
producing a cellulose ester composition is provided. The process
comprises contacting at least one cellulose ester, at least one
compatibilizer, and optionally, at least one plasticizer. The
cellulose ester, plasticizer, and compatibilizer were previously
discussed in this disclosure. The cellulose ester, compatibilizer,
and optional plasticizer can be mixed in any order of addition.
[0089] In another embodiment of this invention, a process for
producing a cellulose ester/elastomer composition is provided
comprising: a) mixing at least one elastomer, at least one
cellulose ester, and at least one additive for a sufficient time
and temperature to disperse the cellulose ester to produce the
cellulose ester/elastomer composition; wherein the additive is at
least one selected from the group consisting of a compatibilizer
and a plasticizer. A sufficient temperature is defined as the flow
temperature of the cellulose ester which is generally about
50.degree. C. above the Tg of the cellulose ester. The temperature
at mixing is limited at the upper range by the processing
temperature of the elastomer and at the lower range by the highest
use temperature of the cellulose ester/elastomer composition.
[0090] It is known in the art that the efficiency of mixing two or
more viscoelastic materials can depend on the ratio of the
viscosities of the viscoelastic materials. For a given mixing
equipment and shear rate range, the viscosity ratio of the
dispersed phase (cellulose ester and additive) and continuous phase
(elastomer) should be within specified limits for obtaining
adequate particle size. In one embodiment of the invention where
low shear rotational shearing equipment is utilized, such as,
Banbury and Brabender mixers, the viscosity ratio of the dispersed
phase (cellulose ester and additive) to the continuous phase
(elastomer) can range from about 0.001 to about 5, from about 0.01
to about 5, and from about 0.1 to about 3. In yet another
embodiment of the invention where high shear rotational/extensional
shearing equipment is utilized, such as, twin screw extruders, the
viscosity ratio of the dispersed phase (cellulose ester and
additive) to the continuous phase (elastomer) can range from about
0.001 to about 500 and from about 0.01 to about 100.
[0091] It is also known in the art that when mixing two or more
viscoelastic materials, the difference between the interfacial
energy of the two viscoelastic materials can affect the efficiency
of mixing. Mixing can be more efficient when the difference in the
interfacial energy between the materials are less. In one
embodiment of the invention, the surface tension difference between
the dispersed phase (cellulose ester and additive) and continuous
phase (elastomer) is less than about 100 dynes/cm, less than 50
dynes/cm, or less than 20 dynes/cm.
[0092] In one embodiment, the cellulose ester is softened and/or
melted to allow breakdown of the cellulose ester into sufficiently
small particle size under the specified mixing conditions. In one
embodiment, the particle size of the cellulose ester can be between
50 microns to 50 nanometers. In one embodiment of the invention,
the elastomer, at least one cellulose ester, and at least one
additive are contacted at a temperature in the range of about
70.degree. C. to about 220.degree. C. or from about 100.degree. C.
to about 180.degree. C., or from about 130.degree. C. to about
160.degree. C.
[0093] Mixing of the elastomer, cellulose ester, and additive can
be accomplished by any method known in the art that is adequate to
disperse the additive. Examples of mixing equipment include, but
are not limited to, Banbury mixers, Brabender mixers, and extruders
(single or twin screw). The shear energy during the mixing is
dependent on the combination of equipment, blade design, rotation
speed (rpm), and mixing time. The shear energy should be sufficient
for breaking down softened/melted cellulose ester to a small enough
size to disperse the cellulose ester throughout the elastomer. For
example, when a Banbury mixer is utilized, the shear energy and
time of mixing ranges from about 5 to about 15 minutes at 100
rpms.
[0094] The elastomer, cellulose ester and additive can be combined
in any order during the process. In one embodiment, the cellulose
ester is premixed with the compatibilizer and/or the plasticizer.
The cellulose ester containing the compatibilizer and/or the
plasticizer is then mixed with the elastomer. In another embodiment
of the invention, when reactive compatibilizers are utilized, the
reactive compatibilizers can be mixed with either the cellulose
ester or the elastomer first, then the other components are
added.
[0095] In another embodiment of the invention, a process to produce
a cellulose ester/elastomer compositions comprising: a) mixing at
least one elastomer, at least one cellulose ester and at least one
additive for a sufficient time and temperature to disperse the
cellulose ester throughout said elastomer to produce a cellulose
ester/elastomer masterbatch; wherein the additive is at least one
selected from the group consisting of a compatibilizer and a
plasticizer; and b) mixing the masterbatch and at least one
elastomer to produce the cellulose ester/elastomer composition. The
elastomer in the masterbatch can be the same or different than that
utilized to produce the cellulose ester/elastomer composition. The
processes of mixing have been previously discussed in this
disclosure.
[0096] This invention can be further illustrated by the following
examples of preferred embodiments thereof, although it will be
understood that these examples are included merely for purposes of
illustration and are not intended to limit the scope of the
invention unless otherwise specifically indicated.
EXAMPLES
Example 1
Non-Reactive Compatibilizer in Cellulose Ester/Elastomer
Compositions
[0097] Experiments were conducted to evaluate certain non-reactive
compatibilizer in cellulose ester/elastomer compositions. In Table
1, the non-reactive compatibilizers evaluated are listed.
TABLE-US-00001 TABLE 1 Compatibilizer Compound MW.sup.1
#CH.sub.2.sup.2 #EO.sup.3 %EO MP.sup.4 .degree. C. Tergitol 15-S-9
570 15 9 63 <RT Tergitol 15-S-30 1400 15 30 85 ~50 Polyethylene
920 32 12 50 ~100 block polyethylene glycol.sup.5 Polyethylene 2250
32 40 80 ~85 block polyethylene glycol Polyethylene 1400 50 16 50
~100 block polyethylene glycol .sup.1Molecular Weight .sup.2Number
of carbon atoms .sup.3Number of Ethylene Oxide groups .sup.4Melting
Point .sup.5PE Block PEG
Tergitol 15-S-9 and Tergitol 15-S-30 are secondary alcohol
ethoxylates obtained from Dow Chemical in Midland, Mich. The
polyethylene block polyethylene glycol compatibilizers were
obtained from Sigma-Aldrich. Although not wishing to be bound by
theory, it is believed that the ethylene oxide units of the above
compounds plasticizes the cellulose acetate butyrate and the
hydrocarbon chain improves compatibility with the elastomer. Each
of the compatibilizers was blended with cellulose acetate butyrate
(CAB 551-0.01 and CAB 553.0.4) obtained from Eastman Chemical
Company, Kingsport, Tenn. at 80:20 ratio in a Brabender mixer at
150.degree. C. for 10 minutes at 100 rpm) followed by cryogrinding
to prepare the masterbatches of cellulose ester and compatibilizer
(MB 1-10) as shown in Table 2.
TABLE-US-00002 TABLE 2 CAB CAB PE PE PE Master 551- 553- Tergitol
Tergitol Block Block Block Batch 0.01 0.4 15-S-9 15-S-30 PEG PEG
PEG Tg, .degree. C. MB 1 80 20 49.3 MB 2 80 20 52.6 MB 3 80 20 54.3
MB 4 80 20 66.6 MB 5 80 20 97.5 MB 6 80 20 82.3 MB 7 80 20 75.8 MB
8 80 20 84.2 MB 9 80 20 69.5 MB 10 80 20 104.7 Reference Tg for CAB
551-0.01 is 107.degree. C. and for CAB 553-0.4 is 139.degree.
C.
All the above master batches of cellulose ester and compatibilizer
are compounded with a non-oil modified solution styrene-butadiene
rubber obtained as Duradene 761 from Firestone Polymers, Akron,
Ohio, using the procedure outlined subsequently in these Examples
to prepare sample compositions shown in Table 3.
TABLE-US-00003 TABLE 3 CAB CAB Comp Duradene 551- 553- No. 761 0.01
0.4 MB 1 MB 2 MB 3 MB 4 MB 5 MB 6 MB 7 MB 8 MB 9 MB 10 1.1 100 1.2
100 10 1.3 100 12.5 1.4 100 12.5 1.5 100 12.5 1.6 100 12.5 1.7 100
12.5 1.8 100 10 1.9 100 12.5 1.10 100 12.5 1.11 100 12.5 1.12 100
12.5 1.13 100 12.5
The amounts specified in Table 3 are based on 100 grams of rubber
and expressed as parts per hundred rubber (phr). For example, for
Composition 1.3, 100 grams of rubber was utilized as well as 12.5
grams of Masterbatch 1, which is an 80:20 ratio of cellulose
acetate butyrate (CAB 553-0.4) and Tergitol 15-S-9 secondary
alcohol ethoxylate.
[0098] All cellulose ester, elastomer, and compatibilizers in Table
3 were processed in a Brabender mixer for 30 minutes at 150.degree.
C. and 100 rpm to produce the cellulose ester/elastomer
composition. Then, 2.5 phr dicumyl peroxide (curing agent) was
added to each sample at 50-60.degree. C. in a Brabender mixer for
about 1 minute and then mixed for another 2-3 minutes to produce a
partially cured cellulose ester/elastomer composition. The samples
from the Brabender mixer were cured by compression molding for 45
minutes at 150.degree. C. and 20000 psi.
[0099] The modulus, yield stress, and yield strain of the
compression molded, cured cellulose ester/elastomer composition
samples were measured as per ASTM D412 and are shown in Table 4. In
the ASTM D412 method, samples were prepared by cutting the
specimens with Die C. The speed of testing was 20 inches/min, and
the gauge length was 63.5 mm (2.5 inch). The samples were
conditioned in the laboratory for 40 hours at 50%+/-5% humidity and
72.degree. F. The width of the specimen was 1 inch and the length
was 4.5 inches.
TABLE-US-00004 TABLE 4 Composition Modulus, Yield Stress, Yield
Number MPa MPa Strain, % 1.1 6.99 1.37 22.11 1.2 7.75 1.66 22.44
1.3 8.29 1.67 24.41 1.4 8.61 1.91 26.67 1.5 7.87 1.86 28.23 1.6
9.57 2.03 26.76 1.7 9.53 1.98 24.73 1.8 10.77 1.27 12.93 1.9 10.14
1.45 16.8 1.10 7.46 1.62 25.88 1.11 6.44 1.16 21.42 1.12 9.08 1.53
20.02 1.13 10.61 1.63 17.33
In Compositions 1.3-1.7, the addition of the compatibilizer to the
elastomer and cellulose ester showed an improvement in modulus,
yield stress, and yield strain over the Comparative Compositions
1.1 and 1.2 containing either rubber alone or rubber and cellulose
ester alone. In Compositions 1.9-1.13, the Yield Strain and Yield
Stress were improved over the Comparative Composition 1.8.
Example 2
Reactive Compatabilizers in Cellulose Ester/Elastomer
Compositions
[0100] Reactive compatibilizers were evaluated to improve the
mixing of CAB in styrene butadiene rubber (SBR). The reactive
compatibilizers were selected such that they contained reactive
groups that can react with the CAB and the rest of the molecule is
compatible with the SBR. The molecular weight, and the type and
concentration of the reactive moiety were varied.
TABLE-US-00005 TABLE 5 Brand Chemical Reactive Acid number, Name
Composition Manufacturer Moiety Mw mg KOH/gm Tm, .degree. C.
Comments SMA Styrene Sartomer/Cray Maleic 9500 285 180 Styrene:MA =
3000 maleic Valley anhydride (Tm ~ 3:1 anhydride Tg + copolymer 55)
Eastman Maleic Eastman Maleic 47000 15 156 G-3015 anhydride
anhydride grafted polypropylene Epolene Maleic Westlake Maleic
15800 45 158 E-43 anhydride Chemicals anhydride grafted
polypropylene Lotader Random Arkema Maleic 17 100 Maleic MAH
terpolymer of anhydride anhydride 8200 Ethylene, ~2.8 wt % Acrylic
ester Ester and Maleic ~6.5 wt % anhydride Lotader Random Arkema
Glycidyl NA 65 Glycidyl GMA AX terpolymer of Methacrylate
Methacrylate 8900 Ethylene, (epoxy) ~8 wt %, Acrylic ester Ester
and glycidyl ~25 wt % Methacrylate Lotader Random Arkema Glycidyl
NA 106 Glycidyl GMA AX terpolymer of Methacrylate Methacrylate 8840
Ethylene, (epoxy) ~8 wt %, Acrylic ester Ester ~0 wt % and glycidyl
Methacrylate
[0101] The maleic anhydride and glycidyl methacrylate in these
reactive compatibilizers can react with the hydroxyl group
contained in the cellulose ester. Masterbatches of Duradene 761
styrene butadiene rubber and a reactive compatibilizer were
produced as shown in Table 6. Duradene 761 styrene butadiene rubber
and the reactive compatibilizer were mixed in a Brabender mixer at
100 rpm and 160.degree. C. for 30 minutes to produce the
masterbatches (MB1-MB6).
TABLE-US-00006 TABLE 6 Duradene 761, Compatibilizer Composition No.
gm Compatibilizer quantity, gm MB1 100 SMA 3000 3 MB2 100 Eastman
G-3015 3 MB3 100 Epolene E-43 3 MB4 100 Lotader MAH 8200 3 MB5 100
Lotader GMA AX 8900 3 MB6 100 Lotader GMA AX 8840 3
The cellulose ester/elastomer compositions produced are shown in
Table 7. Composition Number 2.1 contained only SBR. Composition
Number 2.2 contained only SBR and CAB 551-0.01. For Composition
Numbers 2.3-2.8, the masterbatches produced containing SBR and
compatibilizer were mixed with cellulose ester in a Brabender mixer
at 100 rpm for 30 minutes at 150.degree. C.
[0102] A CAB/plasticizer masterbatch was prepared by blending 100 g
CAB 553-0.4 and 10 g Eastman 168 plasticizer
(bis(2-ethylhexyl)-1,4-benzenedicarboxylate) obtained from Eastman
Chemical Company using a Brabender mixer at 100 rpm and 150.degree.
C. for 10 minutes. The CAB/plasticizer masterbatch was cryo-ground
to a powder. Eastman 168 plasticizer was added to reduce the Tg/Tm
of the CAB 553-0.4 so that it melted at a processing temperature of
about 150.degree. C. The Tg of the CAB/plasticizer masterbatch was
obtained by preparing samples dissolved in acetone followed by
vacuum drying at 70.degree. C. and analyzing the samples by
Differential Scanning calorimetry (DSC) (2nd cycle). Only CAB
553-0.4 was utilized in the masterbatches. CAB 551-0.01 was mixed
with Eastman 168 plasticizer to determine the Tg. The glass
transition temperatures (Tg) of the cellulose ester/plasticizer
compositions produced are shown in Table 8.
TABLE-US-00007 TABLE 7 CAB Composition Duradene 551- MB Number 761
0.01 (CAB/Plasticizer) MB 1 MB 2 MB 3 MB 4 MB 5 MB 6 2.1 100 2.2
100 10 2.3 10 103 2.4 10 103 2.5 10 103 2.6 10 103 2.7 10 103 2.8
10 103 2.9 100 11 2.10 11 103 2.11 11 103 2.12 11 103 2.13 11 103
2.14 11 103 2.15 11 103
TABLE-US-00008 TABLE 8 Plasticizer wt % Tg, .degree. C. CAB
551-0.01 (10 g) + Plasticizer 168 (0.5 g) 5 90.5 CAB 551-0.01 (10
g) + Plasticizer 168 (1.0 g) 10 75.5 CAB 553-0.4 (10 g) +
Plasticizer 168 (0.5 g) 5 123.7 CAB 553-0.4 (10 g) + Plasticizer
168 (1.0 g) 10 109.5
[0103] Once the masterbatches were prepared, the CAB 551-0.01 and
the CAB/Plasticizer Masterbatch were dried overnight at 50.degree.
C. to remove moisture before blending. Composition Numbers 2.1-2.15
were prepared by weighing each component in Table 6 separately and
processing the components in a Brabender mixed at 100 rpm for 30
minutes at 150.degree. C. In order to cure the cellulose
ester/elastomer composition, 1 g of dicumyl peroxide (i.e. 2.5 phr)
was added to the Brabender mixer over a period of about 1 minute
and then the composition was further mixed for another 2-3 minutes
to produce a partially cured cellulose ester/elastomer composition.
The curing of the cellulose ester/elastomer composition was then
completed by compression molding for 45 minutes at 150.degree. C.
and 20000 psi.
[0104] The modulus, yield stress and yield strain of the
compression molded cured samples were measured as per ASTM D412 and
are shown in Table 9.
TABLE-US-00009 TABLE 9 Composition Modulus, Yield Stress, Yield
Number MPa MPa Strain, % 2.1 6.99 1.37 22.11 2.2 7.66 1.45 21.66
2.3 14.08 2.01 18.05 2.4 10.55 1.73 17.62 2.5 7.01 1.45 23.27 2.6
14.65 1.79 13.66 2.7 9.89 1.69 20.00 2.8 11.36 2.2 22.62 2.9 10.48
1.39 14.52 2.10 11.82 1.69 15.23 2.11 9.89 1.72 18.68 2.12 8.92
1.68 20.49 2.13 8.95 1.53 18.49 2.14 6.82 1.32 23.19 2.15 7.35 1.56
25.23
These data show that the addition of CAB 551-0.01 to a masterbatch
of rubber and a reactive compatibilizer in Compositions 2.3-2.8
showed an increase in modulus over Comparative Composition 2.1 with
rubber alone or Composition 2.2 with rubber and CAB 551-0.01. Yield
Strain and to some extent Yield Stress was also improved in
Compositions 2.10-2.15 in comparison to Composition 2.9 when the
CAB/Plasticizer masterbatch was added to the SBR/Compatibilizer
masterbatch.
Example 3
Use of Plasticizers
[0105] Masterbatches of cellulose esters with two different
plasticizers at various loadings were prepared in an attempt to
lower the Tg of the cellulose esters such that their flow
temperature is lower than the typical rubber processing temperature
of 150.degree. C. Compounding in a Brabender mixer at 150.degree.
C. for 10 minutes at 100 rpm followed by cryogrinding yielded the
masterbatches shown in Table 10.
TABLE-US-00010 TABLE 10 Tg of Tg of Master CE, Quantity Type of
Quantity of master Batch CE.sup.1 .degree. C. of CE, g Plasticizer
plasticizer, g Batch, .degree. C. MB 1 CAB 551- 101 100 Eastman
168.sup.2 10 84 0.2 MB 2 CAB 553- 136 100 Eastman 168 25 85 0.4 MB
3 CAB 381- 123 100 Eastman 168 20 87 0.1 MB 4 CAB 381-2 133 100
Eastman 168 25 95 MB 5 CAB 553- 136 100 Poly (ethylene 25 65 0.4
glycol).sup.3 MB 6 CAB 381-2 133 100 Poly (ethylene 25 70 glycol)
MB 7 CAP 504- 159 100 Poly (ethylene 30 93 0.2 glycol) MB 8 CAP
482- 142 100 Poly (ethylene 25 90 0.5 glycol) MB 9 CA 398-3 180 100
Poly (ethylene 40 109 glycol) .sup.1CE--Cellulose Ester .sup.2
bis(2-ethylhexyl)-1,4-benzene dicarboxylate .sup.3polyethylene
glycol - molecular weight 300 - from Aldrich
All the above masterbatches were compounded with styrene butadiene
rubber (SBR). The SBR and the masterbatch were mixed in a Brabender
mixer for 30 minutes at 150.degree. C. and 100 rpm. 2.5 phr dicumyl
peroxide (curing agent) were added to each sample at 50-60.degree.
C. in the Brabender mixer in 1 minute and then mixed for another
2-3 minutes. The samples from the Brabender mixer were compression
molded for 45 minutes at 150.degree. C. and 20000 psi. The
formulation of these samples are shown in Table 11. Each cellulose
ester containing masterbatch sample has 10 phr (parts per hundred
rubber) cellulose ester.
TABLE-US-00011 TABLE 11 Composition No. CE CE Quantity, g Duradene
761, g 3.1 None 100 3.2 MB1 11 100 3.3 MB2 12.5 100 3.4 MB3 12 100
3.5 MB4 12.5 100 3.6 MB5 12.5 100 3.7 MB6 12.5 100 3.8 MB7 13 100
3.9 MB8 12.5 100 3.10 MB9 14 100 comparative?
The modulus, yield stress and yield strain of the compression
molded, cured, elastomer/cellulose ester composition samples were
measured as per ASTM D412 and are shown in Table 12.
TABLE-US-00012 TABLE 12 Composition Modulus, Yield Stress, Yield
Number MPa MPa Strain, % 3.1 6.99 1.37 22.11 3.2 7.47 1.26 19.25
3.3 7.32 1.29 20.45 3.4 12.12 1.83 17.29 3.5 13.45 1.84 14.8 3.6
11.47 1.89 17.99 3.7 13.36 2.07 17.93 3.8 8.43 1.37 18.57 3.9 11.36
1.54 14.83 3.10 10.67 1.44 15.92
These data show that for Composition Numbers 3.2-3.11, the modulus
was improved over Comparative Composition 3.1.
Example 4
Use of Cellulose Esters and Plasticizers in Tire Formulations
[0106] This example is provided to show the advantages of the use
of cellulose esters with plasticizers in tire formulations over
cellulose esters alone. Table 13 shows the tire formulations. All
amounts in Table 13 are based on parts per hundred rubber (phr).
Table 14 shows the cellulose ester/plasticizer masterbatch
formulations.
[0107] Table 15 shows the mixing conditions. The components were
mixed in a Banbury mixer, which was a Farrel BR mixer with steam
heating and water cooling which is instrumented with computer
monitors for temperature, rpm, and power. After preparing the
elastomer/cellulose ester/plasticizer composition, the composition
was cured T.sub.90+5 minutes at 320.degree. F. (160.degree.
C.).
TABLE-US-00013 TABLE 13 Formulations of Cellulose Ester-Filled Tire
Tread Ingredients Sample Name CAB-1 CAB-2 CAB-3 Stage 1 Buna VSL
5025-2.sup.1 S-SBR, 37.5 phr 103.12 103.12 103.12 TDAE.sup.2 Buna
CB24.sup.3 PBD rubber 25 25 25 Rhodia 1165 MP Silica 70 70 70
Si69.sup.4 Coupling agent 5.47 5.47 5.47 Sundex 790.sup.5 Aromatic
Oil 5 5 5 Stearic acid Cure Activator 1.5 1.5 1.5 Stage 2 Product
of stage 1 210.09 210.09 210.09 Cellulose Ester MB.sup.6 MB-1 10
MB-2 12.5 MB-3 12.5 Zinc oxide Cure activator 1.9 1.9 1.9 Okerin
.RTM.wax 7240.sup.7 microcrystalline 1.5 1.5 1.5 wax Santoflex
.RTM.6PPD.sup.8 Anti-oxidant 2 2 2 KK49.sup.9 process aid 2 2 2
Stage 3 Product of stage 2 217.49 229.99 229.99 Sulfur Cross-linker
1.5 1.5 1.5 Santocure .RTM. CBS.sup.10 Accelerator 1.3 1.3 1.3
Perkacit .RTM. DPG- Accelerator 1.5 1.5 1.5 grs.sup.11 Total 221.79
234.29 234.29 Compounds .sup.1S-SBR--solution styrene butadiene
rubber obtained from Lanxess. .sup.2TDAE--treated distillate
aromatic extract .sup.3PBD--polybutadiene rubber obtained from
Lanxess .sup.4Si69 is a sulfur-containing organosilane obtained
from Arkema .sup.5Sundex .RTM. 790 is an aromatic oil obtained from
Sunoco .sup.6MB--Masterbatch .sup.7Okerin wax 7240 is a
microcrystalline wax obtained from Sovereign Chemical
.sup.8Santoflex 6PPD is an anti-oxidant obtained from Flexsys.
.sup.9KK49 is a processing aid obtained from Strutkol.
.sup.10Santocure CBS is an accelerator obtained from Flexsys.
.sup.11Perkacit DPG-grs is an accelerator obtained from
Flexsys.
TABLE-US-00014 TABLE 14 Compositions of Plasticized Cellulose Ester
Masterbatches Pz level Tg before (g/ PHR of MB Tg after MB-
Plasticizer, Plasticizer 100 in plasticizer, Y CE C. (Pz) g CE)
formulation C. MB-1 CAB 133 None -- 10 133 381-2 MB-2 CAB 133 EMN
168.sup.1 25 12.5 95 381-2 MB-3 CAB 133 PEG-300.sup.2 25 12.5 70
381-2
TABLE-US-00015 TABLE 15 Processing of Cellulose-Ester Filled Tire
Tread Compounds in a Banbury Mixer Mix conditions Stage 1 mix
conditions Start temperature 65.degree. C. Starting rotor speed,
rpm 65 Fill factor 67% Mix sequence at 0 minute add elastomers at 1
minute add 2/3 silica + Si69 at 2 minute add 1/3 silica + others at
3 minute sweep at 3.5 minute increase rotor speed to ramp
temperature to 160.degree. C. in 4.5 minutes hold 2 minutes at
160.degree. C. Dump Condition (Total mix time = 6.5 minutes) Stage
2 mix conditions Start temperature 65.degree. C. Starting rotor
speed, rpm 65 Fill factor 64% Mix sequence at 0 minute add 1/2 of
first pass batch at 15 second add other ingredients in a pocket and
1/2 of first pass batch at 1 minute sweep at 1.5 minute increase
rotor speed to ramp temperature to 140-145.degree. C. in 3.5
minutes Hold 4 minutes at 140-145.degree. C. Dump Condition (total
mix time = 7.5 minutes) Stage 3 mix conditions Start temperature
50.degree. C. Starting rotor speed, rpm 60 Fill factor 61% Addition
order at 0 minute add 1/2 2nd pass batch, at 15 second add sulfur,
accelerators and 1/2 2nd pass batch, sweep at 1 minute. Dump
conditions 110.degree. C. or 2 minute 30 second
TABLE-US-00016 TABLE 16 Performance of Cellulose Ester-Filled Tire
Tread Compounds CAB-2 CAB-3 CAB-1 CAB 381-2 CAB 381-2 Properties
CAB 381-2 +25 phc E168 +25 phc PEG Compounding Mooney viscosity, 4
63.5 58.5 55.1 minute at 100.degree. C. Cured Rubber Phillips
Dispersion 1 4 4 Break stress, psi 2191 2240 2349 Break strain, %
386 387 366 Modulus(M100), psi 663 679 735 Modulus (M300), psi 1693
1723 1918 Shore A Hardness 61 59 62 Tan Delta 0.degree. C. 0.306
0.292 0.313 Tan Delta 60.degree. C. 0.082 0.081 0.076 Rebound
0.degree. C., % 9.8 10.8 9.6 Rebound 60.degree. C., % 62.2 62.8
64.0 Wear, volume loss 136 124 127 in mm.sup.3
Performance Measurement:
[0108] Descriptions of various analytical techniques used to
measure performance are provided below: [0109] Mooney Viscosity:
The Mooney Viscosities were measured according to ASTM D 1646.
[0110] PHILLIPS Dispersion Rating: The samples were cut with a
razor blade, and pictures were taken at 30.times. magnification
with an Olympus SZ60 Zoom Stereo Microscope interfaced with a
PaxCam ARC digital camera and a Hewlett Packard 4600 LaserJet color
printer. The pictures of the samples were then compared to a
Phillips standard dispersion-rating chart having standards ranging
from 1 (bad) to 10 (excellent). [0111] Mechanical Properties: Break
stress, break strain, modulus at 100%, and 300% strains were
measured as per ASTM D412 using Die C for specimen preparation. The
speed of testing was 20 inches/min, and the gauge length was 63.5
mm (2.5 inch). The samples were conditioned in the lab for 40 hours
at 50%+/-5% humidity and 72.degree. F. The width of specimen was 1
inch, and length was 4.5 inch. [0112] Hardness: Shore A hardness
was measured according to ASTM D2240. [0113] Dynamic Mechanical
Analysis: [0114] Temperature Sweep: A TA instruments Dynamic
Mechanical Analyzer was used to complete the temperature sweeps
using a tensile geometry. Storage modulus (E'), Loss modulus (E''),
and tan delta (=E''/E') were measured as a function of temperature
from -80.degree. C. to 120.degree. C. using 10 Hz frequency, and 5%
static and 0.2% dynamic strain. [0115] Rebound Test: The rebound
pendulum test was carried out as per ASTM D7121-05. [0116] Wear:
Din abrasion testing was performed per ASTM 222. The data show that
without the use of a plasticizer, the cellulose ester did not
disperse as well through the elastomer as shown by the poor
Phillips Dispersion data. Further, the Mooney viscosities of the
compositions containing both cellulose ester and plasticizer were
lower than when plasticizer was not utilized. This shows that in
the presence of the plasticizer, CEs acted as a processing aid and
lowered Mooney viscosity. Furthermore, the break stress and wear
was also improved over compositions without plasticizer, presumably
indicating that in presence of the plasticizers, CEs can disperse
into finer particles and can improve the properties that are
dependent on particle size and/or surface area.
* * * * *