U.S. patent application number 09/851549 was filed with the patent office on 2001-09-27 for alpha-methylstyrene dimer derivatives.
Invention is credited to Gridnev, Alexei Alexeyevich.
Application Number | 20010025128 09/851549 |
Document ID | / |
Family ID | 22118947 |
Filed Date | 2001-09-27 |
United States Patent
Application |
20010025128 |
Kind Code |
A1 |
Gridnev, Alexei
Alexeyevich |
September 27, 2001 |
Alpha-methylstyrene dimer derivatives
Abstract
The present invention relates to a method of making
alpha-methylstyrene dimers by combining a cobalt catalyst, a
free-radical initiator and an alpha-methylstyrene monomer, in an
inert atmosphere, to form a mixture. The mixture is heated to a
temperature in the range of 65.degree. C. to 140.degree. C. to form
alpha methyl styrene dimers. The present invention also relates to
the products produced by this inventive method.
Inventors: |
Gridnev, Alexei Alexeyevich;
(Wilmington, DE) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY
LEGAL DEPARTMENT - PATENTS
1007 MARKET STREET
WILMINGTON
DE
19898
US
|
Family ID: |
22118947 |
Appl. No.: |
09/851549 |
Filed: |
May 9, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09851549 |
May 9, 2001 |
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09245521 |
Feb 5, 1999 |
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60074322 |
Feb 11, 1998 |
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Current U.S.
Class: |
585/429 ;
585/428 |
Current CPC
Class: |
C07C 275/24 20130101;
C07C 263/16 20130101; C09D 125/02 20130101; C07C 2531/22 20130101;
C07C 15/50 20130101; C07C 209/68 20130101; C07C 2/04 20130101; C08F
12/12 20130101; C07C 2/04 20130101; C07C 15/50 20130101; C07C
209/68 20130101; C07C 211/50 20130101; C07C 263/16 20130101; C07C
265/14 20130101 |
Class at
Publication: |
585/429 ;
585/428 |
International
Class: |
C07C 002/72 |
Claims
1. A process of making alpha-methylstyrene dimers comprising the
steps of: a) adding a cobalt catalyst, a free-radical initiator and
an alpha-methylstyrene monomer, in an inert atmosphere, to form a
mixture; b) heating the mixture to a temperature in the range of
65.degree. C. to 140.degree. C.; and c) forming alpha-methylstyrene
dimers.
2. The process according to claim 1, wherein the free-radical
initiator is selected from the group consisting of azocumene;
2,2'-azobis(2-methyl)-bu- tanenitrile;
2,2'-azobis(isobutyronitrile)(AIBN); 4,4'-azobis(4-cyanovaler- ic
acid); 2-(t-butylazo)-2-cyanopropane;
1,1'-azobis(cyclohexane-1-carboni- trile), and combinations
thereof.
3. The process according to claim 1, wherein the cobalt chain
transfer catalyst is selected from the group consisting of cobalt
(II) and cobalt (III) chelates and combinations thereof.
4. The process according to claim 3, wherein the cobalt catalyst
comprises the general structure 4wherein Z is selected from the
group consisting of hydrogen and BR.sup.20R.sup.21, where R.sup.20
and R.sup.21 are each independently selected from the group
consisting of unsubstituted and substituted aryl, unsubstituted and
substituted C.sub.1-C.sub.12 alkyl, unsubstituted and substituted
C.sub.1-C.sub.12 alkoxy, unsubstituted and substituted aryloxy, and
a halogen; J and K are each independently selected from the group
consisting of phenyl, substituted phenyl, methyl, ethyl, and
--(CH.sub.2).sub.4--; and L is selected from the group consisting
of water, an amine, an ammonia, a phosphine and combinations
thereof.
5. The process according to claim 4 wherein Z is BF.sub.2.
6. The process according to claim 3, wherein the cobalt catalyst
comprises the general structure 5wherein Z is selected from the
group consisting of hydrogen and BR.sup.20R.sup.21, where R.sup.20
and R.sup.21 are each independently selected from the group
consisting of unsubstituted and substituted aryl, unsubstituted and
substituted C.sub.1-C.sub.12 alkyl, unsubstituted and substituted
C.sub.1-C.sub.12 alkoxy, unsubstituted and substituted aryloxy, and
a halogen; J and K are each independently selected from the group
consisting of phenyl, substituted phenyl, methyl, ethyl, and
--(CH.sub.2).sub.4--; L is selected from the group consisting of
water, an amine, an ammonia, a phosphine and combinations thereof;
and Q is an organic radical.
7. The process according to claim 6 wherein Z is BF.sub.2.
8. The process according to claim 1, wherein the mixture of step b)
is heated for at least 5 minutes.
9. The process according to claim 1, wherein the mixture of step b)
is heated for approximately 10 hours to approximately 10 days.
10. The process according to claim 1, wherein the mixture of step
b) is heated to a temperature in the range of 80.degree. C. to
100.degree. C.
11. The process according to claim 1, wherein step a solvent is
added with the cobalt catalyst, the free radical initiator and the
alpha-methylstyrene monomer to form a mixture.
12. A process of making alpha-methylstyrene dimers comprising the
steps of: a) adding a cobalt catalyst, a free-radical-initiator and
an alpha-methylstyrene monomer, in an inert atmosphere, to form a
mixture; b) heating the mixture to a temperature in the range of
65.degree. C. to 140.degree. C.; and c) forming a solution
comprising greater than 20% by weight of alpha-methylstyrene
dimers.
13. The process according to claim 12, wherein a solvent is added
with the cobalt catalyst, the free radical initiator and the
alpha-methylstyrene monomer to form a mixture.
14. The process according to claim 12 further comprising the step
of distilling the polymer solution of step c) to remove the
alpha-methylstyrene monomer.
15. The process according to claim 12, wherein the free radical
initiator is selected from the group consisting of azocumene;
2,2'-azobis(2-methyl)-butanenitrile;
2,2'-azobis(isobutyronitrile)(AIBN); 4,4'-azobis(4-cyanovaleric
acid); 2-(t-butylazo)-2-cyanopropane;
1,1'-azobis(eyclohexane-1-carbonitrile), and combinations
thereof.
16. The process according to claim 12, wherein the cobalt chain
transfer catalyst is selected from the group consisting of cobalt
(II) and cobalt (III) chelates or a mixture thereof.
17. The process according to claim 16, wherein the cobalt catalyst
has the general structure 6wherein Z is selected from the group
consisting of hydrogen and BR.sup.20R.sup.21, where R.sup.20 and
R.sup.21 are each independently selected from the group consisting
of unsubstituted and substituted aryl, unsubstituted and
substituted C.sub.1-C.sub.12 alkyl, unsubstituted and substituted
C.sub.1-C.sub.12 alkoxy, unsubstituted and substituted aryloxy, and
a halogen; J and K are each independently selected from the group
consisting of phenyl, substituted phenyl, methyl, ethyl, and
--(CH.sub.2).sub.4--; and L is selected from the group consisting
of water, an amine, an ammonia, a phosphine and combinations
thereof.
18. The process according to claim 17 wherein Z is BF.sub.2.
19. The process according to claim 16, wherein the cobalt catalyst
has the general structure 7wherein Z is selected from the group
consisting of hydrogen and BR.sup.20R.sup.21, where R.sup.20 and
R.sup.21 are each independently selected from the group consisting
of unsubstituted and substituted aryl, unsubstituted and
substituted C.sub.1-C.sub.12 alkyl, unsubstituted and substituted
C.sub.1-C.sub.12 alkoxy, unsubstituted and substituted aryloxy, and
a halogen; J and K are each independently selected from the group
consisting of phenyl, substituted phenyl, methyl, ethyl, and
--(CH.sub.2).sub.4--; L is selected from the group consisting of
water, an amine, an ammonia, a phosphine and combinations thereof;
and Q is an organic radical.
20. The process according to claim 19 wherein Z is BF.sub.2.
21. The process according to claim 12, wherein the mixture of step
b) is heated for approximately 10 hours to approximately 10
days.
22. The process according to claim 12, wherein the polymer solution
comprises greater than 50% by weight of alpha-methylstyrene
dimer.
23. The process according to claim 12, wherein the mixture of step
b) is heated to a temperature in the range of 80.degree. C. to
100.degree. C.
24. Alpha-methylstyrene derivatives represented by the formula
8wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6
are each independently selected from group consisting of hydrogen,
--CH(O), --CN, isocyanato, thioisocyanato, SO.sub.3H and salts and
esters thereof, NR.sup.7R.sup.8, a silane, a halogen,
--C(O)OR.sup.9, --C(O)NR.sup.10OR.sup.11, --CR.sup.12(O),
--C(O)OC(O)R.sup.13, --C(O)NR.sup.14COR.sup.15, --OC(O)R.sup.16,
--OR.sup.17, substituted and unsubstituted alkyl, substituted and
unsubstituted alkenyl, substituted and unsubstituted alkynyl, and
substituted and unsubstituted aryl; R.sup.7, R.sup.8, R.sup.9,
R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.15, and
R.sup.16 are each independently selected from the group consisting
of H, alkyl, aryl, substituted alkyl or substituted aryl; R.sup.17
is selected from the group consisting of alkyl, aryl, substituted
alkyl or substituted aryl; R.sup.1, R.sup.2, R.sup.3, R.sup.4,
R.sup.5 and R.sup.6 cannot all simultaneously be hydrogen; and the
alkyl and the substituted alkyls have a chain consisting of 1 to 12
carbons.
25. A process of making alpha-methylstyrene dimer derivatives
comprising the steps of: a) adding a cobalt catalyst, a
free-radical initiator and an alpha-methylstyrene monomer
containing a functional group, in an inert atmosphere, to form a
mixture; b) heating the mixture to a temperature in the range of
60.degree. C. to 140.degree. C.; and c) forming alpha-methylstyrene
dimers containing intact functional groups.
26. A process of making alpha-methylstyrene dimer derivatives
comprising the steps of: a) adding a cobalt catalyst, a
free-radical initiator and an alpha-methylstyrene monomer
containing a functional group, in an inert atmosphere, to form a
mixture; b) initiating polymerization with an external source
comprising ultraviolet light, visible light, electron beam or
combinations thereof; and c) forming alpha-methylstyrene dimers
containing intact functional groups.
27. A process of making alpha-methylstyrene dimers comprising the
steps of: a) adding a cobalt catalyst, a free-radical initiator and
an alpha-methylstyrene monomer, in an inert atmosphere, to form a
mixture; b) initiating polymerization with an external source
comprising ultraviolet light, visible light, electron beam or
combinations thereof; and c) forming alpha-methylstyrene
dimers.
28. A product made by the process of claim 1.
29. A polymer comprising at least one polymerized dimer of an
alpha-methyl styrene derivative.
30. A coating comprising a polymer including at least one
polymerized dimer of an alpha-methyl styrene derivative.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to alpha-methylstyrene dimers
and derivatives thereof and to processes of making the same.
BACKGROUND OF THE INVENTION
[0002] Alpha-methylstyrene dimers (AMSDs) may be used as addition
fragmentation chain transfer agents in processes of making polymers
by free radical polymerization. During polymerization reactions,
chain transfer agents may be added to propagating radicals and
undergo fragmentation to create new radical forms. AMSDs, unlike
some other chain transfer agents, are odorless, easy to handle, and
do not cause discoloration or influence the stability of polymers.
Additionally, they provide a method of molecular weight control,
and AMSD containing functional groups such as hydroxyl, vinyl and
amino groups enhance reaction with other functional groups so that
polymers formed thereby may be considered telechelic. Telechelic
polymers are macromolecules having chains of polymerized monomer
comprising reactive functional groups at the terminal ends of the
chains. Telechelic polymers are widely used in the synthesis of
specialty polymers.
[0003] One method of making AMSDs is by the cationic method as
described by Savamoto et. al., Macromolecules 14, 467(1981). Though
this method provides a fairly inexpensive method of making AMSDs,
the method is unable to produced AMSD derivatives (i.e., AMSDs
comprising at least one functional group on one or both rings).
Alpha methylstyrene monomers including functional groups may be
used as starting materials in cationic methods, but functional
groups, such as isocyanato and amino groups, are deactivated by the
acid used during these methods. In addition, a cationic process
tends to provide low yields of AMSDs of which a substantial
percentage exits as an "internal" isomer. Please see FIG. 1. Some
commercially available preparations of AMSDs believed to be
prepared by a cationic method contain about 7% by weight of AMSDs
existing as an "internal" isomer. AMSDs existing as an "external"
isomer (Please see FIG. 2) show significantly higher reaction rates
when used in processes of addition chain transfer compared to
"internal" isomers which are relatively inert in such
processes.
[0004] Another method of making AMSDs is by the radical
polymerization process. This process is described in Yamada, et
al., Journal of Polymer Science, Part A, Polymer Chemistry, Vol.
32, 2745-2754 (1994), which discloses a method of producing
alpha-methylstyrene dimers using
benzylbis(dimethylglyoximato)(pyridine)cobalt(III) and a reaction
temperature of 60.degree. C. Unfortunately, the method produces low
AMSDs yields. Research performed on the polymerization
characteristics of alpha-methylstyrene monomers reveals that
polymerization occurs until a ceiling temperature, is reached. Then
the polymerization of alpha-methylstyrene monomers into polymeric
products is inhibited above the ceiling temperature. Martinet et.
al., Journal of Applied Polymer Science, Vol. 65, 2297-2313 (1997)
reports an alpha-methylstyrene monomer polymerization ceiling
temperature of 61.degree. C.
SUMMARY OF THE INVENTION
[0005] The present invention provides a dimerization process for
making alpha-methylstyrene dimers in high yields. The process
comprises the following steps:
[0006] a) adding a cobalt chain transfer catalyst, a free-radical
initiator and an alpha-methylstyrene monomer, in an inert
atmosphere, to form a mixture;
[0007] b) heating the mixture to a temperature in the range of
65.degree. C. to 140.degree. C.; and
[0008] c) forming alpha-methylstyrene dimers.
[0009] The dimerization process yields a solution that comprises
greater than 20% by weight, and preferably greater than 50% by
weight, of AMSDs.
[0010] The present invention also provides alpha-methylstyrene
derivatives represented by the formula 1
[0011] wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and
R.sup.6 are each independently selected from group consisting of
hydrogen, --CH(O), --CN, isocyanato, thioisocyanato, SO.sub.3H and
salts and esters thereof, NR.sup.7R.sup.8, a silane, a halogen,
--C(O)OR.sup.9, --C(O)NR.sup.10R.sup.11, --CR.sup.12(O),
--C(O)OC(O)R.sup.13, --C(O)NR.sup.14COR.sup.15, --OC(O)R.sup.16,
--OR.sup.17, substituted and unsubstituted alkyl, substituted and
unsubstituted alkenyl, substituted and unsubstituted alkynyl, and
substituted and unsubstituted aryl; R.sup.7, R.sup.8, R.sup.9,
R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.15, and
R.sup.16 are each independently selected from the group consisting
of H, alkyl, aryl, substituted alkyl or substituted aryl; R.sup.17
is selected from the group consisting of alkyl, aryl, substituted
alkyl or substituted aryl; R.sup.1, R.sup.2, R.sup.3, R.sup.4,
R.sup.5 and R.sup.6 cannot all simultaneously be hydrogen; and the
alkyl and substituted alkyls have a chain consisting of 1 to 12
carbons.
[0012] As used herein, with respect to the present invention, the
following shall apply:
[0013] "alpha-methylstyrene monomer" refers to alpha-methylstyrene
monomer, derivatives thereof, or combinations of
alpha-methylstyrene monomer and derivatives thereof, unless
otherwise stated.
[0014] "derivatives" refer to alpha-methylstyrene monomers
comprising one or more functional groups such as amino, isocyanato
and hydroxyl groups, for example.
[0015] "alpha-methylstyrene dimer" or AMSD refers to a dimer
prepared from alpha-methylstyrene monomers defined above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The present invention will be further explained with
reference to the figures.
[0017] FIG. 1 illustrates an AMSD existing as an "internal"
isomer.
[0018] FIG. 2 illustrates an AMSD existing as an "external"
isomer.
[0019] FIG. 3 illustrates the dimerization process of PROCEDURES 2,
3, 5, 7, and 9.
DETAILED DESCRIPTION OF THE INVENTION
[0020] The present invention provides dimerization processes for
making alpha-methylstyrene dimers in high yields using reaction
temperatures in the range of 65.degree. C. to 140.degree. C.,
preferably in the range of 80.degree. C. to 100.degree. C. Because
these dimerization processes do not involve cationic transfer,
AMSDs, which include intact functional groups, are formed. In
addition, most solutions prepared by the dimerization process of
the present invention comprise less than 0.1% by weight of dimer
existing as an "internal" isomer. FIG. 1 illustrates an AMSD
existing as an "internal" isomer. For comparison purposes, FIG. 2
illustrates an AMSD existing as an "external" isomer. AMSDs in the
form of "external" isomers are useful in further polymerization
reactions, unlike AMSDs in the form of "internal" isomers.
[0021] The inventive dimerization process begins by combining, in
an inert atmosphere, a cobalt catalyst, a free-radical initiator
(generally an azo-initiator), an alpha-methylstyrene monomer and
optionally other additives in a flask (e.g., solvent(s)). The
resultant mixture is referred to as the reaction mixture. By "inert
atmosphere" is meant an atmosphere substantially free of oxygen,
generally provided by blanketing with nitrogen, argon, carbon
dioxide, or other gas considered unreactive or inert with respect
to reactants. Oxygen may be removed by freeze pump-thawing, flash
vacuumation, or other methods known to those skilled in the art.
The reactants are generally mixed, usually for a couple of minutes,
before the heating step, to insure the catalyst and initiator are
dissolved.
[0022] Preferred cobalt chain transfer catalysts for use in the
practice of the present invention include cobalt (II) and cobalt
(III) microcyclic chelates. Examples of such cobalt compounds and
their structure are disclosed in Davis et al., J. M. S. -Rev.
Macromol. Chem. Phys., C34(1), 243-324 (1994). Additional examples
of such cobalt chain transfer catalysts are disclosed in U.S. Pat.
No. 4,680,352 (Ittel et al.), U.S. Pat. No. 4,694,054 (Ittel et
al.), U.S. Pat. No. 5,324,879 (Hawthorne et al.), WO 87/03605
(Hawthorne et al.) published Jun. 18, 1987, U.S. Pat. No. 5,362,826
(Antonelli et al.), and U.S. Pat. No. 5,264,530 (Antonelli et al.).
Other useful cobalt compounds (cobalt complexes of porphyrins,
phthalocyanines, tetraazoporphyrins, and cobaloximes) are disclosed
in USSR Patent 664,434 (Enikolopov, N. S., et al.); USSR Patent
856,096 (Golikov, I., et al.); USSR Patent 871,378 (Belgovskii, I.
M.); and USSR Patent 1,306,085 (Belgovskii, I. M., et al.).
Examples of cobalt (II) and cobalt (III) chain transfer catalysts
include, but are not limited to, those represented by the following
structures: 2
[0023] Referring to structures (I) and (II), Z can be hydrogen or
BR.sup.20R.sup.21, where R.sup.20 and R.sup.21 are each
independently selected from the group consisting of unsubstituted
and substituted aryl, unisubstituted and substituted
C.sub.1-C.sub.12 alkyl, unsubstituted and substituted
C.sub.1-C.sub.12 alkoxy, unsubstituted and substituted aryloxy, and
a halogen. Preferably Z is BF.sub.2. J and K are preferably
independently selected from the group consisting of phenyl,
substituted phenyl, methyl, ethyl, or --(CH.sub.2).sub.4--. L can
be any one of a variety of neutral ligands commonly known in
coordination chemistry and may be selected from the group
consisting of water, amines, ammonia, and phosphines. Q is
preferably an organic radical selected from the group consisting of
isopropyl, 1-cyanoethyl, and 1-carbomethoxyethyl. Q may also be
selected from the group consisting of alkyl, substituted alkyl or
halogen. The catalysts can also include cobalt complexes of a
variety of porphyrin molecules such as tetraphenylporphyrin,
tetraanisylporphyrin, tetramesitylporphyrin and other substituted
porphyrin species.
[0024] Regarding structure (I), some useful cobalt catalyst
include:
1 Co(II)(DPG-Z).sub.2, where J = K = Phenyl (Ph), L = ligand
Co(II)(DMG-Z).sub.2, where J = K = Methyl (Me), L = ligand
Co(II)(EMG-Z).sub.2, where J = Me, K = Ethyl (Et), L = ligand
Co(II)(DEG-Z).sub.2, where J = K = Et, L = ligand
Co(II)(CHG-Z).sub.2, where J = K = --(CH.sub.2).sub.4--, L =
ligand
[0025] Regarding structure (II), some useful cobalt catalyst
include:
2 QCo(III)(DPG-Z).sub.2, where J = K = Ph, Q = alkyl, L = ligand
QCo(III)(DMG-Z).sub.2, where J = K = Me, Q = alkyl, L = ligand
QCo(III)(EMG-Z).sub.2, where J = Me, K = Et, Q = alkyl, L = ligand
QCo(III)(DEG-Z).sub.2, where J = K = Et, Q = alkyl, L = ligand
QCo(III)(CHG-Z).sub.2, where J = K = --(CH.sub.2).sub.4--, Q =
alkyl, L = ligand QCo(III)(DMG-Z).sub.2, where J = K = Me, Q =
halogen, L = ligand DPG = diphenylglyoxime DMG = dimethylglyoxime
EMG = ethylmethylglyoxime DEG = diethylglyoxime CHG =
cyclohexylglyoxime
[0026] The reaction mixture used in the inventive process may
comprise from about 1 parts per million to 100 parts per thousand
of catalyst and preferably in the range from about 100 parts per
million to 10 parts per thousand. Cobalt catalyst are selected for
use in a particular dimerization process, in part, based on factors
such as solubility, monomer properties (e.g., polarity) and the
like. One or more cobalt catalysts may be used in a dimerization
process.
[0027] A free-radical initiator which produces carbon-centered
radicals, sufficiently mild so as not to destroy the metal chelate
chain transfer catalysts, is preferably employed in preparing
AMSDs. Suitable initiators for use in the practice of the present
invention are azo compounds having the requisite solubility and
appropriate half life, including azocumene;
2,2'-azobis(2-methyl)-butanenitrile;
2,2'-azobis(isobutyronitrile)(AIBN); 4,4'-azobis(4-cyanovaleric
acid); 2-(t-butylazo)-2-cyanopropane;
1,1'-azobis(cyclohexane-1-carbonitrile) and other compounds known
to those skilled in the art.
[0028] A reaction mixture may comprise approximately 0.01% to
approximately 10% by weight, preferably approximately 0.5% to
approximately 3% by weight of azo-initator. Azo-initiators are
selected for a particular dimerization process, in part, based
primarily on the recommended reaction temperature. One or more
azo-initiators may be used in a dimerization process.
[0029] A reaction mixture also comprises alpha-methylstyrene
monomers selected on the basis of the AMSDs to be formed. For
example, an AMSD containing an isocyanate functional group may be
prepared from an alpha-methylstyrene monomer comprising an
isocyanate group. The preferred alpha-methylstyrene monomers used
in the inventive process are those shown in FIG. 3. Each ring of an
alpha-methylstyrene monomer may contain one or more functional
groups. The functional groups located on each ring may be all the
same, all different, or a combination of functional groups that are
the same and that are different. A reaction mixture may comprise
approximately 1% to approximately 100% by weight, preferably
approximately 30% to approximately 100% by weight of
alpha-methylstyrene monomer. One or more alpha-methylstyrene
monomers may be used in a dimerization process.
[0030] The reaction mixture is heated to a reaction temperature in
the range of approximately 65.degree. C. to approximately
140.degree. C., preferably in the range of 80.degree. C. to
approximately 100.degree. C. The reaction mixture may be heated
below 65.degree. C., for example between 60.degree. C. and
65.degree. C. In some situations, an AMSD with an intact functional
group may be prepared at low reaction temperatures if yield is not
necessarily important. The reaction mixture may be heated by using
a flame, oven or any other heating method that is known by one
skilled in the art. The reaction mixture remains heated at the
elevated temperature for at least 5 minutes up to 5 to 10 days, or
even longer, depending upon the reactants used. Preferably the
heating step has a duration in the range of approximately 30
minutes to approximately 12 hours and a solution comprising AMSDs
is formed. Step heating may also be used in the inventive process
wherein the reaction mixture is elevated to different temperatures
for specified periods of time. Methods of initiating radical
polymerization known by one skilled in the art may be used in the
process of the present invention. The polymerization process may be
initiated using an external source such as ultraviolet light,
visible light, electron beam, or combinations thereof, for example.
Initiating the polymerization process by heat is preferred.
[0031] The polymers made by the inventive process are typically
prepared in a polymerization reaction by standard solution
polymerization techniques, but may also be prepared by emulsion,
suspension or bulk polymerization processes. The polymerization
process can be carried out as either a batch, semi-batch, or
continuous process (CSTR). When carried out in the batch process,
the reaction mixture is prepared by combining monomer and metal
chain transfer catalyst and adding this solution to a desired
amount of initiator. Preferably the monomer-to-initiator ratio of
the reaction mixture is 5 to 1000. The mixture is then heated for
the requisite time, as described above. In a batch process, the
reaction may be run under pressure to avoid monomer reflux.
[0032] As indicated above, the polymerization can be carried out in
the absence of, or in the presence of, any medium or solvent
suitable for free-radical polymerization, including, but not
limited to, ketones such as acetone, butanone, pentanone and
hexanone; alcohols such as isopropanol; amides such as dimethyl
formamide; aromatic hydrocarbons such as toluene and xylene; ethers
such as tetrahydrofuran and diethyl ether; ethylene glycol; dialkyl
ethers, alkyl esters or mixed ester ethers such as monoalkyl
ether-monoalkanoates; and mixtures of two or more solvents.
[0033] The solution formed, after the heating step, may comprise
greater than 20% by weight, and preferably greater than 50% by
weight, of AMSDs. A polymer solution may comprise, by weight
percent, 20% to about 95% of AMSDs, preferably about 50% to about
95% of AMSDs. The polymer solution preferably comprises AMSDs in
the form of "external" dimers with less than 0.1% (by weight) of
the polymer solution comprising AMSDs existing as "internal"
isomers. The free alpha-methylstyrene monomers not incorporated
into dimers may be removed from the polymer solution by separation
techniques well known in the art. The preferred separation
technique is vacuum distillation, which removes unreacted monomer,
solvent and other volatiles from the reaction products. AMSDs
prepared according to the present invention can be used, not only
as non-metallic chain transfer agents, but as components or
intermediates in the production of graft copolymers, non-aqueous
dispersed polymers, block copolymers, microgels, star polymers,
branched polymers, and ladder polymers.
[0034] Alpha-methylstyrene derivatives produced may be represented
by the formula 3
[0035] wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and
R.sup.6 are each independently selected from group consisting of
hydrogen, --CH(O), --CN, isocyanato, thioisocyanato, SO.sub.3H and
salts and esters thereof, NR.sup.7R.sup.8, a silane, a halogen,
C(O)OR.sup.9, --C(O)NR.sup.10R.sup.11, --CR.sup.12(O),
--C(O)OC(O)R.sup.13, --C(O)NR.sup.14COR.sup.15, --OC(O)R.sup.16,
--OR.sup.17, substituted and unsubstituted alkyl, substituted and
unsubstituted alkenyl, substituted and unsubstituted alkynyl, and
substituted and unsubstituted aryl; R.sup.7, R.sup.8, R.sup.9,
R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.15, and
R.sup.16 are each independently selected from the group H, alkyl,
aryl, substituted alkyl or substituted aryl; R.sup.17 is selected
from the group alkyl, aryl, substituted alkyl or substituted aryl;
R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 cannot all
simultaneously be hydrogen. It is preferred that the alkyl and
substituted alkyls have a chain consisting of 1 to 12 carbons. It
is also preferred that substituents located on the substituted
alkyl or substituted aryl are free of functionalities that could
substantially interfere with free radical polymerization.
[0036] In addition, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 or
R.sup.6 may optionally form a cyclic structure selected from the
group consisting of C(O)OR.sup.9, --C(O)NR.sup.10R.sup.11,
--CR.sup.12(O), --C(O)OC(O)R.sup.13, --C(O)NR.sup.14COR.sup.15,
--OC(O)R.sup.16, --OR.sup.17, substituted and unsubstituted alkyl,
substituted and unsubstituted alkenyl, substituted and
unsubstituted alkynyl.
[0037] Polymers may be prepared using alpha-methylstyrene dimers of
the present invention, preferably using alpha-methylstyrene dimers
as chain transfer agents. The methods used to prepare polymers of
the present invention are those well known in the art such as
radical polymerization or group transfer polymerization, for
example. The polymers formed comprise at least one polymerized
dimer of an alpha-methylstyrene derivative.
[0038] Chain transfer agents used in a polymerization process
include methacrylate low oligomers, alpha-methylstyrene low
oligomers, addition-fragmentation chain transfer agents, catalytic
chain transfer agents (i.e., cobalt chelates, mercaptans, etc.),
mercaptans, or combinations thereof. Other materials used to
prepare polymers of the present invention include at least one
ethylenically unsaturated monomer, such as, for example,
alpha-methylene-gamma-butyrolactone and substituted
alpha-methylene-gamma-butyrolactone, acrylic ester monomers
including methyl acrylate, ethyl acrylate, butyl acrylate,
2-ethylhexyl acrylate, decyl acrylate, methyl methacrylate, butyl
methacrylate, lauryl(meth)acrylate, isobornyl (meth)acrylate,
isodecyl(meth)acrylate, oleyl(meth)acrylate, palmityl
(meth)acrylate, stearyl(meth)acrylate, hydroxymethyl(meth)acrylate,
hydroxyethyl (meth)acrylate, and hydroxypropyl(meth)acrylate;
acrylamide or substituted acrylamides; styrene or substituted
styrenes; butadiene; vinyl acetate or other vinyl esters; vinyl
monomers, such as, for example, vinyl chloride, vinylidene
chloride, N-vinyl pyrrolidone; amino monomers, such as, for
example, N,N'-dimethylamino(meth)acrylate; and acrylonitrile or
methacrylonitrile. Additionally copolymerizable
ethylenically-unsaturated acid monomers in the range of, for
example, from 0.1 percent to 7 percent, by weight based on the
weight of the emulsion-polymerized polymer, acrylic acid,
methacrylic acid, crotonic acid, itaconic acid, fumaric acid,
maleic acid, monomethyl itaconate, monomethyl fumarate, monobutyl
fumarate, maleic anhydride, 2-acrylamido-2-methyl-1-propanesulfonic
acid, sodium vinyl sulfonate, and phosphoethyl methacrylate, may be
used. Polymer prepared using AMSDs may be in the form of a solution
or a dispersion of polymer particles.
[0039] The polymers of the present invention form a composition
that may be used to prepare coatings. Polymer compositions of the
present invention may include a substantially thermoplastic or
substantially uncrosslinked polymer when applied to the substrate
prior to the formation of a coating. A coating is formed when the
polymer composition is hardened. Crosslinking or gelling of the
polymer composition may be induced by adding to the monomer mix
reactive diluents comprising ethylenically unsaturated groups and/
or multi-ethylenically unsaturated monomers. Multi-ethyleneically
unsaturated monomers preferably are in the range of 0.01% to 5%, by
weight based on the weight of the polymer. Preferably
multi-ethylenically unsaturated monomers include allyl
methacrylate, trimethylolpropane triacrylate, diallyl phthalate,
1,4-butylene glycol dimethacrylate, 1,6-hexanedioldiacrylate and
divinyl benzene. The multi-ethylenically unsaturated monomers are
selected so that film formation is not materially impaired.
Initiators used in the hardening process include conventional free
radical initiators, such as, azo-initiators, hydrogen peroxide,
benzoyl peroxide, t-butyl hydroperoxide, t-butyl peroctoate,
ammonium, alkali persulfates and combinations thereof. Preferably
the initiator is used in a concentration typically of 0.05% to 3.0%
by weight, based on the weight of the polymer composition.
Initiation may be enhanced by the use of external sources such as
heat, ultraviolet light, electron beam or other sources known by
one skilled in the art. The coatings of the present invention are
preferably low VOC coating compositions. "Low VOC coating
compositions" means a coating composition that includes less then
0.6 kilograms of organic solvent per liter (5 pounds per gallon) of
the composition, as determined under the procedure provided in ASTM
D3960. It is also preferred that the coatings of the present
invention are a high solids composition. "High solid composition"
means a coating composition having solid component of above 40
percent, preferably in the range of from 45 to 85 percent and more
preferably in the range of from 50 to 65 percent, all in weight
percentages based on the total weight of a polymer composition.
[0040] A coating composition containing the polymer prepared by the
process of the present invention may also contain conventional
additives, such as, reactive diluents, pigments, stabilizers, flow
agents, toughening agents, fillers, durability agents, corrosion
and oxidation inhibitors, rheology control agents, metallic flakes
and other additives. Such additional additives will, of course,
depend on the intended use of the coating composition. Fillers,
pigments, and other additives that would adversely effect the
clarity of the cured coating will not be included if the
composition is intended as a clear coating.
[0041] The coatings of the present invention can be used as
automotive coatings such as refinishes, primers, basecoats,
undercoats, overcoats and clear coats. The polymers are also
suitable for use in compositions for maintenance finishes for a
wide variety of substrates, such as steel, copper, brass and
aluminum or non-metallic substrates, such as, wood, leather,
polymeric materials and concrete.
EXAMPLES
[0042] The examples below are carried out using standard
techniques, which are well known and routine to those skilled in
the art, except where otherwise described in detail. These examples
are illustrative, but do not limit the invention. In all cases, the
presence of the internal isomer was not detected, and is therefore
assumed to be present at levels below 0.1 wt. %.
[0043] The freeze-pump-thaw cycle as used in the examples below is
described in D. F. Shriver, et al., "The Manipulation of Air
Sensitive Compounds", 2nd ed., Wiley Interscience, 1986.
[0044] .sup.1H-NMR spectra were taken on a QE300 NMR spectrometer
(General Electric Co., Freemont, Calif. 94539) at 300 MHz
frequency.
[0045] Molecular weight (MW) and Degrees of Polymerization (DP)
measurements were based on size exclusion chromatography (SEC)
using styrene as a standard, and performed on a WISP 712
Chromatograph with 100A, 500A, 1000A and 5000A phenogel columns
(Waters Corp., Marlborough, Mass.).
[0046] Unless otherwise specified, all chemicals and reagents were
used as received from Aldrich Chemical Company, Milwaukee, Wis.
DEFINITIONS
[0047]
3 VAZO-52 2,2"-azobis(2,4-dimethylvaleronitrile) (DuPont Co.,
Wilmington, DE) VAZO-67 2,2'-azobis(2-methylbutyron- itrile)
(DuPont Co., Wilmington, DE) VAZO-88
1,1'-azobis(cyclohexane-1-carbonitrile) (DuPont Co., Wilmington,
DE) AIBN 2,2'-azobis(isobutyronitrile) TAPCo
tetraanisylporphyrine-Co HPCo hemato-porphyrin-IX-Co tetramethyl
ester THPCo [meso-tetrakis(4- heptyloxyphenyl)porphyrinat-
o]cobalt(II) COBF [bis[m-(2,3-butanedione dioximato)(2-)-
o,o']]tetrafluorodiborato(2-)-N,N',N",N"'](2- propyl)Co(III)
(DuPont Co., Wilmington, DE)
[0048] Procedure 1
[0049] Procedure 1 is a dimerization process illustrating a
reaction mixture free of a cobalt catalyst will not form AMSDs.
[0050] A reaction mixture was prepared in a 500 milliliter flask by
combining 140 milliliters of alpha-methylstyrene (AMS) and a
solution of 1.2 grams of VAZO-52 dissolved in 60 milliliters of
acetone. The reaction mixture was degassed by three
freeze-pump-thaw cycles. The flask containing the reaction mixture
was immersed into 60.degree. C. isothermal bath and incubated for
24 hours. An additional 0.6 grams of VAZO-52 was added followed by
the degassing procedure described above. After degassing, the
reaction mixture was incubated a second time at 60.degree. C. for
24 hours and a solution was formed containing AMSDs. Approximately
1 milliliter of the solution was analyzed by both Nuclear Magnetic
Resonance (NMR) and Size Exclusion Chromatography (SEC) indicating
the sample was substantially free of alpha-methylstyrene dimer or
higher oligomer.
[0051] Procedure 2
[0052] Procedure 2 is a dimerization process illustrating a low
reaction temperature (60.degree. C.) will yield decreased amounts
(21.3 weight %) of AMSDs. Please observe FIG. 3.
[0053] The dimerization process described in PROCEDURE 1 was
followed. However, an additional component, 80 milligrams of COBF
was added to the reaction mixture. After the second incubation, the
solution was placed under a high vacuum (approximately 0.5 torrs)
to remove acetone and residual monomer. Approximately 1 milliliter
of the solution comprising AMSDs was analyzed by both NMR and SEC
revealing that the sample was substantially free of trimers and
higher oligomers. About 30 grams (21.3 weight %) of pure AMSD was
prepared with the remainder of the solution comprising
monomers.
[0054] Procedure 3
[0055]
[0056] Procedure 3 is a dimerization process illustrating elevated
reaction temperatures (90.degree. C.) will yield elevated amounts
(48 weight %) of AMSDs. Please observe FIG. 3.
[0057] A reaction mixture was prepared in a 500 milliliter flask by
combining 180 milliliters of AMS, 120 milligrams of COBF and a
solution of 2 grams of VAZO-88 dissolved in 25 milliliters of
acetone. The reaction mixture was degassed by flash-vacuumation
(i.e., the flask was attached to a vacuum line for 2 minutes). The
flask containing the reaction mixture was immersed into a
90.degree. C. isothermal bath and incubated for 24 hours. The
temperature was raised to 95.degree. C. and the reaction mixture
was incubated a second time for 24 hours. Upon completion of the
second incubation, a solution containing AMSDs was formed and
placed under a high vacuum (approximately 0.05 torr) to remove both
acetone and residual monomer. Approximately 1 milliliter of the
solution comprising AMSDs was analyzed by both NMR and SEC
revealing the solution was substantially free of trimers and higher
oligomers. About 86 grams (48 weight percent of the solution) of
AMSDs were prepared and the remainder of the solution was
substantially monomer.
[0058] Procedure 4
[0059] Procedure 4 is a dimerization process illustrating a
reaction mixture free of a cobalt catalyst will not form AMSDs.
[0060] A reaction mixture was prepared in a 500 milliliter flask by
combining 10 milliliters of meta-diiso-propenylbenzene (m-DIPB) and
a solution of 50 milligrams of VAZO-67 dissolved in 3 milliliters
of dichloroethane. The reaction mixture was degassed by
flash-vacuumation for 2 minutes. The flask containing the reaction
mixture was immersed into a 65.degree. C. isothermal bath and
incubated for 48 hours to form a solution containing AMSDs.
Approximately 1 milliliter of the solution was analyzed by both NMR
and SEC revealing that the solution was substantially free of
AMSDs.
[0061] Procedure 5
[0062] Procedure 5 is a dimerization process illustrating elevated
reaction temperatures (65.degree. C.) will yield elevated amounts
(50 weight %) of AMSDs with intact vinyl functional groups. Please
observe FIG. 3.
[0063] The dimerization process described in PROCEDURE 4 was
followed. However, an additional component, 1.6 milligrams of COBF
was added to the reaction mixture. After the incubation step, the
solution was placed under a high vacuum (approximately 0.5 torrs)
to remove acetone and residual monomer. Approximately 1 milliliter
of the solution containing AMSDs was analyzed by both NMR and SEC
revealing the solution was substantially free of trimers and higher
oligomers. About 50% by weight of the solution was AMSDs and the
rest of the solution was substantially monomers.
[0064] Procedure 6
[0065] Procedure 6 is a dimerization process illustrating a
reaction mixture free of a cobalt catalyst will not form AMSDs.
[0066] A reaction mixture was prepared in a 500 milliliter flask by
combining 4 milliliters of 3-isopropenyl-alpha,
alpha-dimethylbenzyl isocyanate and a solution of 80 milligrams of
VAZO-88 dissolved in 4 milliliters of dichloroethane. The reaction
mixture was degassed. The flask containing the reaction mixture was
immersed in a 65.degree. C. isothermal bath and incubated for 6
days to form a solution containing AMSDs. The solution was chilled
and an excess of diethylamine was added to convert isocyanate
groups into diethylurea. The polymer solution was placed under a
high vacuum (approximately 0.05 torr) to yield white waxy crystals.
Approximately 1 gram of the crystals were analyzed by both NMR and
SEC revealing the crystals were substantially free of AMSDs.
[0067] Procedure 7
[0068] Procedure 7 is a dimerization process illustrating elevated
reaction temperatures (65.degree. C.) will yield elevated amounts
(75 weight %) of AMSDs with intact isocyanate groups. Please
observe FIG. 3.
[0069] The dimerization process described in PROCEDURE 6 was
followed. However, an additional component, 6 milligrams of TAPCo
was added to the reaction mixture. Approximately 1 milliliter of a
solution was formed containing AMSDs and the solution was analyzed
by both NMR and SEC revealing the solution was substantially free
of trimers and higher oligomers. The solution containing, by
weight, about 75% AMSDs and the rest of the solution was
substantially monomers.
[0070] Procedure 8
[0071] Procedure 8 is a dimerization process illustrating a
reaction mixture free of cobalt catalyst will not form AMSDs.
[0072] A reaction mixture was prepared in a 500 milliliter flask by
combining 10 milliliters of ortho-isopropenylaniline, 10
milliliters of 1,2-dichloroethane and 0.18 grams initiator VAZO-88.
The reaction mixture was degassed by three freeze-pump-thaw cycles.
The flask containing the reaction mixture was immersed in a
90.degree. C. bath for 2 days to form a polymer solution containing
AMSDs. Approximately 1 milliliter of the solution was analyzed by
both NMR and SEC revealing the solution was substantially free of
AMSDs.
[0073] Procedure 9
[0074] Procedure 9 is a dimerization process illustrating elevated
temperatures (90.degree. C.) will yield AMSDs having intact amino
functional groups. Please observe FIG. 3.
[0075] The dimerization process described in PROCEDURE 8 was
followed. However, an additional compound, 7 milligrams of THPCo,
was added to the reaction mixture. Upon completion of the
incubation step, a solution containing AMSDs was formed and placed
under a high vacuum (approximately 0.05 torr) to remove both
acetone and residual monomer. Approximately 1 milliliter of a
solution was analyzed by both NMR and SEC revealing the solution
was substantially free of trimer and higher oligomer. The solution
comprises approximately 9% dimer formation and the remainder of the
solution was substantially monomers.
[0076] The complete disclosures of all patents, patent
applications, and publications are incorporated herein by reference
as if individually incorporated. Various modifications and
alterations of this invention will become apparent to those skilled
in the art without departing from the scope and spirit of this
invention, and it should be understood that this invention is not
to be unduly limited to the illustrative embodiments set forth
herein.
* * * * *