U.S. patent application number 10/863023 was filed with the patent office on 2004-11-04 for high-molecular weight polymers and methods of manufacture.
Invention is credited to Arthur, Donald James, Sridharan, Srinivasan, Tam, Thomas Yiu-Tai, Young, John Armstrong.
Application Number | 20040217582 10/863023 |
Document ID | / |
Family ID | 26951895 |
Filed Date | 2004-11-04 |
United States Patent
Application |
20040217582 |
Kind Code |
A1 |
Sridharan, Srinivasan ; et
al. |
November 4, 2004 |
High-molecular weight polymers and methods of manufacture
Abstract
A composition comprises a solid-stated block copolymer of an
aromatic polyester and a caprolactone, wherein the copolymer has
been solid state polymerized such that intrinsic viscosity
increases at least 20%, the caprolactone content decreases no more
than 1.2% absolute and the transesterification increases no more
than 3.5% absolute, and wherein the solid-stated copolymer has an
intrinsic viscosity of at least 0.82. Particularly preferred chain
extension reactions are performed at a temperature of less than
175.degree. C., and even more preferably at less than 165.degree.
C. In further aspects of the inventive subject matter, yarns and
methods of producing a fiber include contemplated solid-stated
block copolymers.
Inventors: |
Sridharan, Srinivasan;
(Morgan Hill, CA) ; Young, John Armstrong;
(Midlothian, VA) ; Arthur, Donald James; (Chester,
VA) ; Tam, Thomas Yiu-Tai; (Richmond, VA) |
Correspondence
Address: |
ROBERT D. FISH
RUTAN & TUCKER LLP
611 ANTON BLVD 14TH FLOOR
COSTA MESA
CA
92626-1931
US
|
Family ID: |
26951895 |
Appl. No.: |
10/863023 |
Filed: |
June 7, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10863023 |
Jun 7, 2004 |
|
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10266517 |
Oct 8, 2002 |
|
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60335153 |
Nov 14, 2001 |
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Current U.S.
Class: |
280/801.1 ;
528/323 |
Current CPC
Class: |
C08G 63/60 20130101;
C08G 63/80 20130101 |
Class at
Publication: |
280/801.1 ;
528/323 |
International
Class: |
B60R 022/00; C08G
069/14 |
Claims
1. A composition comprising: a solid state polymerized block
copolymer comprising an aromatic polyester and a caprolactone,
wherein the copolymer has been polymerized in the solid state at a
temperature sufficient to achieve an increase in intrinsic
viscosity of at least 20%, a decrease in caprolactone content of no
more than 1.2% absolute, and an increase in transesterification of
no more than 3.5% absolute; and wherein the solid-stated block
copolymer has an intrinsic viscosity of at least 0.82, a
caprolactone content of less than 15 wt % and less than 6%
transesterification.
2. The composition of claim 1 wherein the aromatic polyester
comprises a compound selected from the group consisting of a
poly(alkylene terephthalate), a poly(alkylene naphthalate), and a
poly(cycloalkylene naphthalate).
3. The composition of claim 1 wherein the copolymer has been
solid-state polymerized at a temperature of no more than
175.degree. C.
4. The composition of claim 1 wherein the copolymer has been
solid-state polymerized at a temperature of no more than
165.degree. C.
5. The composition of claim 4 wherein the aromatic polyester
comprises poly(ethylene terephthalate).
6. The composition of claim 5 wherein the decrease in caprolactone
content is no more than 0.1% absolute.
7. The composition of claim 6 wherein the increase in
transesterification is no more than 0.2% absolute.
8. The composition of claim 3 wherein the increase in intrinsic
viscosity is at least 35%, and wherein the aromatic polyester
comprises poly(ethylene terephthalate).
9. The composition of claim 8 wherein the increase in
transesterification is no more than 0.6% absolute.
10. The composition of claim 1 wherein the caprolactone content is
no more than 30 mol %.
11. The composition of claim 1 wherein the caprolactone content is
no more than 15 mol %.
12. A chip comprising the composition of claim 1.
13. A Film comprising the composition of claim 1.
14. A yarn comprising a fiber produced from the composition of
claim 1.
15. A yarn comprising a fiber produced from the composition of
claim 6.
16. A yarn comprising a fiber produced from the composition of
claim 7.
17. A yarn comprising a fiber produced from the composition of
claim 8.
18. A webbing comprising the composition of claim 1.
19. A seat belt comprising the webbing of claim 18.
20. (Canceled)
21. (Canceled)
22. (Canceled)
23. (Canceled)
24. (Canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to pending U.S. provisional
application serial No. 60/335,153, filed Nov. 14, 2001, the entire
contents of which are incorporated by reference.
FIELD OF THE INVENTION
[0002] The field of the invention is high-molecular weight
polymers.
BACKGROUND OF THE INVENTION
[0003] Many known copolymers comprising an aromatic polyester and
caprolactone are known in the art and used in numerous applications
as thermoplastic elastomers. For example, Japanese Patent
Publication 4115 (published Feb. 5, 1973) describes copolymers in
which the aromatic polyester is poly(ethylene terephthalate) (PET)
or poly(butylene terephthalate) (PBT). The average molecular weight
of some of these copolymers is within a range of about 500-5,000,
which corresponds to an intrinsic viscosity (IV) of less than 0.3
(as measured in a 60/40 by weight mixture of phenol and
tetrachloroethane solvents according to William L. Hergenrother and
Charles Jay Nelson, "Viscosity-Molecular Weight Relationship for
Fractionated Poly(ethylene Terephthalate)", Journal of Polymer
Science (1974),12, 2905-2915). Unfortunately, copolymers having
such relatively low IV are generally insufficient for spinning
high-performance fibers.
[0004] The molecular weight can be extended to at least some degree
by reacting the aromatic polyester and caprolactone in the presence
of a polyfunctional acylation agent, thereby forming a multiblock
copolymer as also described in the Japanese Patent Publication
4115. Although such a copolymerization generally increases the
molecular weight and intrinsic viscosity of the resulting product,
various disadvantages still remain. For example, the intrinsic
viscosity of the aromatic polyesters used in such copolymerizations
is relatively low. Consequently, the resulting copolymers and
multiblock copolymers will exhibit comparably low molecular weight,
intrinsic viscosity, and relatively short block lengths. Moreover,
due to the conditions employed during the polymerization process
(particularly temperature and residence time in the reactor), the
rate of transesterification may be undesirably high.
[0005] To circumvent or at least alleviate most of the
aforementioned problems with block copolymers comprising an
aromatic polyester and caprolactone, copolymerization may be
carried out under conditions as described in U.S. Pat. No.
5,869,582 to Tang et al. Tang's copolymer is formed from an
aromatic polyesters with relatively high intrinsic viscosity (IV of
about 0.9) and lactone monomers. Furthermore, the copolymerization
is performed in a reactor having a configuration that significantly
reduces residence time, and wherein the melt in the process of
polymerization is under continuous agitation of intermeshing
turbulators and homogenization of advancing/combining mixers.
However, numerous advanced applications and fibers demand block
copolymers with even higher molecular weight and intrinsic
viscosity.
[0006] While it is known for certain polymers to increase the
molecular weight after polymerization in the solid state,
solid-stating block copolymers comprising an aromatic polyester and
caprolactone using known protocols typically results in an
increased molecular weight, but in significant loss of caprolactone
concurrent with a substantial increase in transesterification. For
example, when temperatures normally employed for PET solid-stating
are used in solid stating of a PET-caprolactone copolymer, numerous
significant and often undesirable changes may occur. Among other
things, at temperatures of about 200.degree. C., the percent
esterification can increase by a factor of two, and at temperatures
of about 210-215.degree. C., the loss of caprolactone can be as
much as 10% of the total amount present.
[0007] Although various methods and compositions are known in the
art to produce block copolymers from an aromatic polyester and
caprolactone, all, or almost all of them suffer from one or more
problems. Thus, there is still a need to provide compositions and
methods for production of such block copolymers, especially block
copolymers with improved intrinsic viscosity.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to solid-stated block
copolymers from aromatic polyester and caprolactone. Such
copolymers have been solid state polymerized under a protocol to
increase the intrinsic viscosity at least 20%, while decreasing the
caprolactone content no more than 1.2% absolute and increasing the
transesterification no more than 3.5% absolute. Preferred
solid-stated copolymers have an intrinsic viscosity of at least
0.82.
[0009] In one aspect of the inventive subject matter, the protocol
includes heating of the copolymer to a temperature of no more than
175.degree. C., more preferably to a temperature of no more than
165.degree. C., wherein the heating is preferably performed under a
nitrogen sweep. It is further contemplated that especially where
the aromatic polyester comprises poly(ethylene terephthalate), the
decrease in caprolactone content is no more than 0.1% absolute, and
the increase in transesterification is no more than 0.2% absolute.
In further alternative aspects, the increase in intrinsic viscosity
of such polymers is at least 35% and the increase in
transesterification is no more than 0.6% absolute.
[0010] In another aspect of the inventive subject matter, the
aromatic polyester in preferred copolymers is a poly(alkylene
terephthalate) such as poly(ethylene terephthalate) and
poly(butylene terephthalate), a poly(alkylene naphthalate) such as
poly(ethylene naphthalate) and poly(butylene naphthalate), or a
poly(cycloalkylene naphthalate).
[0011] In a still further aspect of the inventive subject matter, a
method of producing a fiber comprises a step in which contemplated
block copolymers are provided. In a further step, the copolymer is
solid-stated to achieve an increase in intrinsic viscosity of at
least 20%, a decrease in caprolactone content of no more than 1.2%
absolute, and an increase in transesterification of no more than
3.5% absolute, wherein the solid-stated copolymer has an intrinsic
viscosity of no less than 0.82. In a still further step, the
solid-state polymerized copolymer is spun to a fiber. Consequently,
it is contemplated that yarns may be spun from contemplated block
copolymers.
[0012] Various objects, features, aspects and advantages of the
present invention will become more apparent from the following
detailed description of preferred embodiments of the invention.
DETAILED DESCRIPTION
[0013] The inventors discovered that a block copolymer of an
aromatic polyester and a caprolactone can be solid-stated (i.e.,
the molecular weight of the polymer can be increased while the
polymer is in the solid state) to significantly advance the IV
while substantially maintaining caprolactone content and
transesterification. More particularly, the inventors surprisingly
observed that conditions similar to conditions employed for drying
are sufficient for such solid stating.
[0014] In a particularly preferred aspect o,f the inventive subject
matter, the block copolymer is a block copolymer of polyethylene
terephthalate and caprolactone with IV of about 0.76, a
caprolactone content of about 13.2 wt %, and a transesterification
of approximately 5.2%, which is commercially available from
Honeywell under the trade name SECURUS.TM. material, and which is
solid-stated using the following protocol: Crystallization cycle at
120.degree. C. under vacuum at 15 mm Hg for 8 hrs, followed by
incubation at 152.degree. C. under nitrogen sweep for 24 hrs.
[0015] However, it should be appreciated that while a block
copolymer of polyethylene terephthalate and caprolactone with an IV
of about 0.76, a caprolactone content of about 13.2 wt %, and a
transesterification of approximately 5.2% may be used, numerous
alternative copolymers are also considered suitable for use in
conjunction with the teachings presented herein. For example, the
aromatic polyester in alternative copolymers need not be restricted
to polyethylene terephthalate, but may also include other
poly(alkylene terephthalates), poly(alkylene naphthalates), and
poly(cycloalkylene naphthalates), wherein the alkylene unit in such
polymers may have between 2 to 10 carbon atoms, and more preferably
between 2 and 6 carbon atoms. Further preferred copolymers have a
caprolactone content of no more than 30 mol %, and more preferably
of no more than 15 mol %.
[0016] While it is generally preferred that contemplated copolymers
are block copolymers, it should also be appreciated that additional
blocks may be included in suitable copolymers. Consequently,
multiblock copolymers (e.g., comprising 3,4, or even more
chemically distinctive blocks) are also contemplated. Furthermore,
it should be appreciated that where the polymers are multiblock
copolymers, all reasonable combinations of suitable blocks are
contemplated. In yet further contemplated aspects, suitable
copolymers may be derivatized or modified with various substituents
and/or functional group. For example, where flame retardancy is
particularly desired, contemplated polymers may include bromine or
brominated groups. On the other hand, where adhesion to rubbers is
desired, contemplated polymers may include epoxy groups.
[0017] With respect to the intrinsic viscosity of contemplated
copolymers, it should be appreciated that a particular intrinsic
viscosity is not limiting to the inventive subject matter. However,
it is especially preferred that the IV of suitable copolymers will
be in the range of between about 0.5 to 1.4, and more typically in
the range of between about 0.6 to 1.2, and most typically in the
range of between about 0.8 to 1.1. (As measured in a 60/40 by
weight mixture of phenol and tetrachloroethane according to William
L. Hergenrother and Charles Jay Nelson, "Viscosity-Molecular Weight
Relationship for Fractionated Poly(ethylene Terephthalate)",
Journal of Polymer Science (1974),12, 2905-2915).
[0018] Similarly, contemplated starting copolymers may have a
caprolactone content other than about 13.2 wt % and a
transesterification of other than approximately 5.2%. The
particular caprolactone content will typically depend on the molar
fraction of caprolactone (monomer) in the polymerization mixture
and polymerization efficiency of the employed polymerization
process. Likewise, the degree of transesterification will
predominantly depend on the particular polymerization process (and
especially on the temperature and residence time) used in the
fabrication of the copolymer. Consequently, it is contemplated that
suitable copolymers will include caprolactone in a range of between
about 3 wt % to about 85 wt %, more preferably between about 5 wt %
to about 40 wt %, and most preferably between about 10 wt % to
about 15 wt %. With respect to the degree of transesterification,
relatively low degrees are generally preferred, and contemplated
degrees of transesterification are in the range of about 0.5% and
less to about 25%. However, in especially preferred aspects of the
inventive subject matter, the degree of transesterification is less
than 10%, and most preferably less than 6%.
[0019] Contemplated copolymers may be synthesized following
numerous known procedures, and the synthesis of especially
preferred copolymers (block copolymers comprising an aromatic
polyester and caprolactone) is described in commonly assigned U.S.
Pat. No. 5,869,582 to Tang et al., which is incorporated by
reference herein. However, all other known protocols for synthesis
of contemplated copolymers are also considered suitable for use in
conjunction with the teachings presented herein.
[0020] With respect to the solid-stating protocol for contemplated
copolymers, it should be appreciated that numerous protocols are
appropriate, so long as such protocols will increase the IV at
least 20%, decrease the caprolactone content of the copolymer no
more than 1.2% absolute, and increase the transesterification no
more than 3.5% absolute, wherein the solid-stated copolymer has an
IV of no less than 0.82.
[0021] Consequently, the crystallization cycle may be performed at
temperatures other than 120.degree. C. and at a pressure other than
vacuum at 15 mmHg. For example, where crystallization can be
performed over a relatively long period, or where a vacuum of less
than 15 mmHg is applied, suitable temperatures may be in the range
of between about 75.degree. C. to 90.degree. C. and less, or
between 90.degree. C. and 119.degree. C. On the other hand, where
transesterification occurs at relatively high temperatures,
suitable temperatures may be in the range of between about
121.degree. C. to 140.degree. C. and even more. Consequently, the
duration of the crystallization may be less than 16 hrs (e.g.,
between 8 hrs and 12 hrs, and even less), where water is removed at
a relatively high rate. On the other hand, and especially where the
temperature is relatively low or the vacuum is relatively weak,
crystallization times of more than 16 hrs are contemplated. With
respect to the vacuum, it is generally preferred that the vacuum is
lower than 50 mm Hg, and even more preferably that the vacuum is
lower than 20 m Hg. However, in alternative aspects, the vacuum may
be in the range between 50 mm Hg and atmospheric pressure. Where
the vacuum is relatively weak (i.e., above 50 mmHg), it is
especially preferred that the crystallization is performed under a
protective gas atmosphere (e.g., nitrogen). Furthermore, it is
contemplated that the crystallization cycle may be omitted
altogether, or that only partial crystallization may be done,
wherein the degree of crystallization may be monitored using X-ray
diffraction.
[0022] In further alternative aspects of the inventive subject
matter, various heating steps other than an incubation at
152.degree. C. under nitrogen sweep for 24 hrs are contemplated. In
fact, all heating steps are contemplated suitable so long as
alternative heating steps (i.e., incubations at one or more
particular temperatures) will increase the IV at least 20%,
decrease the caprolactone content of the copolymer no more than
1.2% absolute, and increase the transesterification no more than
3.5% absolute wherein the solid-stated copolymer has an IV of no
less than 0.82.
[0023] For example, where a relatively low degree of
transesterification is especially important, incubation of the
copolymer may be performed at a temperature between about
135.degree. C. and 150.degree. C., or between 120.degree. C. and
135.degree. C., and even less. On the other hand, where the
incubation period is significantly shorter than 24 hrs, incubation
of the copolymer may be performed at a temperature between about
150.degree. C. and 170.degree. C., or between 170.degree. C. and
185.degree. C. and higher. However, it is generally preferred that
the incubation is performed at a temperature of no more than
175.degree. C., and more preferably at a temperature of no more
than 165.degree. C.
[0024] Similarly, the length of the incubation period may vary
considerably, and will predominantly depend on the copolymer type,
the desired degree of increase in intrinsic viscosity, and the
amount of transesterification tolerated. Consequently, suitable
incubations periods will generally be in the range of several
minutes (and even less) to incubations of one or more days.
However, it is generally preferred that the length of incubation
will be in the range of about 2 hrs to approximately 24 hrs. It is
further preferred that the incubation of the copolymer will be
performed under a protective atmosphere, typically under nitrogen
sweep.
[0025] It should further be appreciated that incubations may be
performed at more than one temperature, wherein suitable
incubations may include multiple temperature levels and temperature
gradients. For example, contemplated incubations may have a segment
of incubation at 160.degree. C. for 6 hrs, which may be followed by
a segment of incubation at 150.degree. C. for 18 hrs.
Alternatively, contemplated incubations may also include a linear
(or non-linear) temperature gradient starting at 175.degree. C. to
145.degree. C. over a period of 24 hrs.
[0026] In still further alternative aspects of the inventive
subject matter, the incubation may be performed in the presence of
additional chemical agents. For example, where appropriate, a
catalyst may be included in the preparation of contemplated
copolymers to assist the chain extension reaction. Alternatively,
moisture absorbing agents may included to further remove water not
displaced during the crystallization. Moreover, it is generally
contemplated that incubation and crystallization of copolymer is
independent of the shape or geometry of the copolymer. However, it
is also contemplated that surface of copolymer may be increased to
potentially increase rate of chain extension. On the other hand,
where desirable, the copolymer may also be in form of a sphere to
decrease the ratio of surface to volume.
[0027] Thus, contemplated solid-stating protocols according to the
inventive subject matter will significantly increase the IV while
only moderately (e.g., between 0% and 3.5% absolute, more typically
between 0% and 0.8% absolute, and most typically between 0% and
0.2% absolute) increasing transesterification and moderately
decreasing the caprolactone content. In particular, it should be
appreciated that contemplated copolymers will increase the IV in an
amount of at least 20%, more preferably in an amount of at least
25%, even more preferably in an amount of at least 35%, and most
preferably in an amount of at least 45%. Furthermore, contemplated
preferred solid-stating protocols will decrease the caprolactone
content in copolymers in an amount of no more than 1.2% absolute,
more preferably in an amount of no more than 0.8% absolute, even
more preferably in an amount of no more than 0.2% absolute, and
most preferably in an amount of no more than 0.1% absolute, while
increasing the transesterification in an amount of no more than
3.5% absolute, more preferably in an amount of no more than 2.0%
absolute, even more preferably in an amount of no more than 0.6%
absolute, and most preferably in an amount of no more than 0.2%
absolute.
[0028] Chip of the present solid-stated copolymer may be formed.
The formed chip may then be used for fiber formation including
monofilament, film applications. spunbonded (non-continuous) fiber,
molded parts, or extruded profiles.
[0029] Furthermore, it is contemplated that yarns may be fabricated
from fibers produced from contemplated solid stated block
copolymers. Thus, a method of producing a fiber has one step in
which a block copolymer comprising an aromatic polyester and a
caprolactone is provided. In another step, the copolymer is
solid-state polymerized at a temperature sufficient to achieve an
increase in intrinsic viscosity of at least 20%, a decrease in
caprolactone content of no more than 1.2% absolute, and an increase
in transesterification of no more than 3.5% absolute, wherein the
solid-stated copolymer has an intrinsic viscosity of no less than
0.82. In still another step, the solid-state polymerized copolymer
is spun.
[0030] The present composition may be spun into a fiber using a
known spinning process. The resulting yarn may be used in numerous
industrial fiber applications including webbing, textile, safety
belts, parachute harnesses and lines, shoulder harnesses, cargo
handling, safety nets, trampolines, high altitudes worker
harnesses, military aircraft arrestor tapes, ski tow lines, and
rope and cordage applications including yacht and oil derrick
cordage.
EXAMPLES
[0031] The following examples are provided to illustrate various
aspects of the inventive subject matter. In particular, the
following examples are based on a block copolymer comprising
poly-(ethylene terephthalate) and caprolactone. Among other
suitable block copolymers, appropriate block copolymers include the
commercially available copolymer under the trade name
SECURUS.TM.
[0032] IV was determined using a protocol as described in
Viscosity-Molecular Weight Relationship for Fractionated
Poly(ethylene Terephthalate), published in the Journal of Polymer
Science (1974),12, 2905-2915 by William L. Hergenrother and Charles
Jay Nelson. COOH content, %Transesterification, and %Caprolactone
were determined by NMR following a protocol as described in U.S.
Pat. No. 5,869,582 to Tatig et al. IV is expressed as dl/g, while
COOH content is indicated as meq/kg. %TE is % transesterification,
and %CL is % caprolactone, and are expressed as absolute numbers.
Unless indicated otherwise, solid stating conditions are given in
hours of incubation at the particular temperature shown in Tables 1
and 2.
1TABLE 1 Sample Solid Stating Condition IV COOH % TE % CL 1 SECURUS
Chip (Starting 0.74 38 5.1 13.1 Material) 2 5 hrs at 120.degree. C.
and 16 hrs at 0.94 24 5.8 13.0 160.degree. C. 3 8 hrs at
120.degree. C. 0.77 33 4.5 13.2 4 8 hrs at 120.degree. C. and 24
hrs at 1.01 23 5.7 12.9 161.degree. C. 5 8 hrs at 120.degree. C.
and 25 hrs at 0.94 26 5.3 13.2 152.degree. C.
[0033]
2TABLE 2 Sample Solid Stating Condition IV COOH % TE % CL 1 SECURUS
Chip (Starting 0.74 38 5.1 13.1 Material) 6 5 hrs at 120.degree.
C., 16 hrs at 1.45 13 9.9 13.0 160.degree. C., 3 hrs at 180.degree.
C., and 16 hrs at 200.degree. C. 7 5 hrs at 120.degree. C., 16 hrs
at 1.91 11 10.2 11.8 160.degree. C., 3 hrs at 180.degree. C., 16
hrs at 200.degree. C., 4 hrs at 200.degree. C., 2 hrs at
210.degree. C., and 7 hrs at 215.degree. C.
[0034] As can be appreciated from Table 2, higher solid stating
temperatures generally tend to increase IV, however, will typically
result in significant increase of transestefification, and decrease
of caprolactone.
[0035] Thus, specific embodiments and applications of
high-molecular weight polymers and methods of manufacture have been
disclosed. It should be apparent, however, to those skilled in the
art that many more modifications besides those already described
are possible without departing from the inventive concepts herein.
The inventive subject matter, therefore, is not to be restricted
except in the spirit of the appended claims. Moreover, in
interpreting both the specification and the claims, all terms
should be interpreted in the broadest possible manner consistent
with the context. In particular, the terms "comprises" and
"comprising" should be interpreted as referring to elements,
components, or steps in a non-exclusive manner, indicating that the
referenced elements, components, or steps may be present, or
utilized, or combined with other elements, components, or steps
that are not expressly referenced.
* * * * *