U.S. patent application number 09/764931 was filed with the patent office on 2002-09-19 for process for producing poly (1, 4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate) and the reactor grade polyester therefrom.
Invention is credited to Quillen, Donna Rice.
Application Number | 20020132963 09/764931 |
Document ID | / |
Family ID | 26933404 |
Filed Date | 2002-09-19 |
United States Patent
Application |
20020132963 |
Kind Code |
A1 |
Quillen, Donna Rice |
September 19, 2002 |
PROCESS FOR PRODUCING POLY (1, 4-CYCLOHEXYLENEDIMETHYLENE
1,4-CYCLOHEXANEDICARBOXYLATE) AND THE REACTOR GRADE POLYESTER
THEREFROM
Abstract
In a process for producing a reactor grade polyester, a
poly(1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate) has
a reduced amount of isomerization of the trans-isomer to the
cis-isomer of 1,4-dimethylcyclohexanedicarboxylate and an increased
polymerization rate by the addition of a phosphorus-containing
compound to the reaction process. In step (a) of the process, a
diacid comprising at least 80 mole percent
1,4-cyclohexanedicarboxylic acid or an ester derivative of the
diacid comprising at least 80 mole percent
1,4-dimethylcyclohexanedicarbo- xylate is reacted with a glycol
comprising at least 80 mole percent 1,4-cyclohexanedimethanol at a
temperature sufficient to effect esterification for the diacid or
transesterification for the ester derivative. In step (b), the
product of step (a) is subjected to temperatures and pressures in
the presence of a suitable catalyst to effect polycondensation.
Phosphorus in an amount of 1 to 800 ppm is added in the form of a
phosphorus-containing compound during the process.
Inventors: |
Quillen, Donna Rice;
(Kingsport, TN) |
Correspondence
Address: |
Cheryl J. Tubach
Eastman Chemical Company
P.O. Box 511
Kingsport
TN
37662-5075
US
|
Family ID: |
26933404 |
Appl. No.: |
09/764931 |
Filed: |
January 18, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60240432 |
Oct 13, 2000 |
|
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Current U.S.
Class: |
528/287 |
Current CPC
Class: |
C08G 63/82 20130101;
C08G 63/78 20130101; C08G 63/199 20130101 |
Class at
Publication: |
528/287 |
International
Class: |
C08L 001/00 |
Claims
What is claimed is:
1. A process for producing a reactor grade polyester of
poly(1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate)
comprising the steps of: a) reacting a diacid comprising at least
80 mole percent 1,4-cyclohexanedicarboxylic acid or an ester
derivative of the diacid comprising at least 80 mole percent
1,4-dimethylcyclohexanedicarbo- xylate and a glycol comprising at
least 80 mole percent 1,4-cyclohexanedimethanol at a temperature
sufficient to effect esterification for the diacid or
transesterification for the ester derivative, wherein the diacid or
the ester derivative is based on 100 mole percent and the glycol is
based on 100 mole percent; b) polycondensing the product of step
(a) at temperatures and pressures in the presence of a suitable
catalyst to effect polycondensation; c) adding 1 to 800 ppm
phosphorus, wherein all parts by weight are based on the weight of
the polyester and the phosphorus is added in the form of a
phosphorus-containing compound; and d) after step (c) removing a
reactor grade polyester of poly(1,4-cyclohexylenedimethylene
1,4-cyclohexanedicarboxylate) having an inherent viscosity of 0.4
to 2.0 dL/g; wherein the phosphorus-containing compound is selected
from the group consisting of: (1) a phosphate ester having the
formula: 10wherein R.sub.1 is a hydrogen atom or a C.sub.1-C.sub.20
radical, which optionally includes O, Cl or Br atoms, and R.sub.2
and R.sub.3 are the same C.sub.1-C.sub.20 radical or a combination
of different C.sub.1-C.sub.20 radicals, which optionally include O,
Cl or Br atoms; (2) a phosphate ester having the formula: 11wherein
R is derived from a diol; R.sub.1 and R.sub.4 can be hydrogen atoms
or C.sub.1-C.sub.20 radicals, which optionally include O, Cl or Br
atoms; and R.sub.2 and R.sub.3 are the same C.sub.1-C.sub.20
radical or a combination of different C.sub.1-C.sub.20 radicals,
which optionally include O, Cl or Br atoms; (3) a diphosphate ester
having the formula: 12wherein R.sub.1 and R.sub.4 can be hydrogen
atoms or C.sub.1-C.sub.20 radicals, which optionally include O, Cl
or Br atoms, and R.sub.2 and R.sub.3 are the same C.sub.1-C.sub.20
radical or a combination of different C.sub.1-C.sub.20 radicals,
which optionally include O, Cl or Br atoms; and (4) a phosphonate
ester having the formula: 13wherein R.sub.1 is a hydrogen atom or a
C.sub.1-C.sub.20 radical, which optionally includes O, Cl or Br
atoms, and R.sub.2 and R.sub.3 are the same C.sub.1-C.sub.20
radical or a combination of different C.sub.1-C.sub.20 radicals,
which optionally include O, Cl or Br atoms.
2. The process of claim 1 wherein step (c) adding the
phosphorus-containing compound occurs prior to step (a).
3. The process of claim 1 wherein step (c) adding the
phosphorus-containing compound occurs prior to step (b).
4. The process of claim 1 wherein the phosphorus-containing
compound contains no more than one --OH group bonded to each
phosphorus molecule.
5. The process of claim 1 wherein the phosphorus-containing
compound is selected from the group consisting of trimethyl
phosphate, triethyl phosphate, tributyl phosphate, tributoxyethyl
phosphate, tris(2-ethylhexyl) phosphate, trioctyl phosphate,
triphenyl phosphate, tritolyl phosphate, ethylene glycol phosphate,
triethyl phosphonoacetate, dimethyl methyl phosphonate, and
tetraisopropyl methylenediphosphonate.
6. The process of claim 1 wherein the phosphorus-containing
compound is selected from the group consisting of the phosphate
ester of group (1) wherein R.sub.1, R.sub.2 and R.sub.3 are the
same C.sub.1-C.sub.20 radical or a combination of different
C.sub.1-C.sub.20 radicals, which optionally include O, Cl or Br
atoms, and the phosphate ester of group (2) wherein R is derived
from a diol; R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same
C.sub.1-C.sub.20 radical or a combination of different
C.sub.1-C.sub.20 radicals, which optionally include O, Cl or Br
atoms.
7. The process of claim 6 wherein the phosphorus-containing
compound is selected from the group consisting of trimethyl
phosphate, triphenyl phosphate, tributyl phosphate, trioctyl
phosphate, tritolyl phosphate, tributoxyethyl phosphate, ethylene
glycol phosphate and tris(2-ethylhexyl) phosphate.
8. The process of claim 6 wherein the phosphorus-containing
compound has a molecular weight greater than about 300 g/mol.
9. The process of claim 1 wherein the diacid comprises at least 90
mole percent 1,4-cyclohexanedicarboxylic acid.
10. The process of claim 9 wherein the diacid comprises 100 mole
percent of 1,4-cyclohexanedicarboxylic acid.
11. The process of claim 1 wherein the ester derivative comprises
at least 90 mole percent 1,4-dimethylcyclohexanedicarboxylate.
12. The process of claim 11 wherein the ester derivative comprises
100 mole percent of 1,4-dimethylcyclohexanedicarboxylate.
13. The process of claim 1 wherein the glycol comprises at least 90
mole percent 1,4-cyclohexanedimethanol.
14. The process of claim 13 wherein the glycol comprises 100 mole
percent 1,4-cyclohexanedimethanol.
15. The process of claim 1 further comprising an esterification
catalyst or transesterification catalyst selected from the group
consisting of titanium, calcium, barium, strontium, chromium,
zirconium and aluminum.
16. The process of claim 1 where in the suitable catalyst for
polycondensation is selected from the group consisting of titanium,
germanium, zirconium and aluminum.
17. The process of claim 1 wherein the esterification catalyst or
transesterification catalyst and the suitable catalyst for
polycondensation is titanium and the titanium is present in a molar
ratio of phosphorus to titanium of 0.2 to 2.4.
18. The process of claim 17 wherein the molar ratio of phosphorus
to titanium is 0.4 to 1.4.
19. The process of claim 1 wherein the phosphorus from the
phosphorus-containing compound is added in an amount of 1 to 310
ppm.
20. The process of claim 19 wherein the phosphorus from the
phosphorus-containing compound is added in an amount of 5 to 91
ppm.
21. A reactor grade polyester produced by the process of claim
1.
22. A reaction product polyester composition of
poly(1,4-cyclohexylenedime- thylene 1,4-cyclohexanedicarboxylate)
having an inherent viscosity of 0.4 to 2.0 dL/g comprising: a) a
diacid component of residues of at least about 80 mole percent of
1,4-cyclohexanedicarboxylic acid, based on 100 mole percent diacid
component; (b) a glycol component of residues of at least about 80
mole percent of 1,4-cyclohexanedimethanol, based on 100 mole
percent glycol component; c) 0 to 500 ppm esterification catalyst
or 1 to 500 ppm transesterification catalyst; d) 1 to 500 ppm
polycondensation catalyst, and e) 1 to 800 ppm phosphorus present
in the form of phosphorus-containing compound, all parts per weight
based on the weight of the polyester; wherein the
phosphorus-containing compound is selected from the group
consisting of: (1) a phosphate ester having the formula: 14wherein
R.sub.1 is a hydrogen atom or a C.sub.1-C.sub.20 radical, which
optionally includes O, Cl or Br atoms, and R.sub.2 and R.sub.3 are
the same C.sub.1-C.sub.20 radical or a combination of different
C.sub.1-C.sub.20 radicals, which optionally include O, Cl or Br
atoms; (2) a phosphate ester having the formula: 15wherein R is
derived from a diol; R.sub.1 and R.sub.4 can be hydrogen atoms or
C.sub.1-C.sub.20 radicals, which optionally include O, Cl or Br
atoms; and R.sub.2 and R.sub.3 are the same C.sub.1-C.sub.20
radical or a combination of different C.sub.1-C.sub.20 radicals,
which optionally include O, Cl or Br atoms; (3) a diphosphate ester
having the formula: 16wherein R.sub.1 and R.sub.4 can be hydrogen
atoms or C.sub.1-C.sub.20 radicals, which optionally include O, Cl
or Br atoms, and R.sub.2 and R.sub.3 are the same C.sub.1-C.sub.20
radical or a combination of different C.sub.1-C.sub.20 radicals,
which optionally include O, Cl or Br atoms; and (4) a phosphonate
ester having the formula: 17wherein R.sub.1 is a hydrogen atom or a
C.sub.1-C.sub.20 radical, which optionally includes O, Cl or Br
atoms, and R.sub.2 and R.sub.3 are the same C.sub.1-C.sub.20
radical or a combination of different C.sub.1-C.sub.20 radicals,
which optionally include O, Cl or Br atoms.
23. The polyester composition of claim 22 wherein the
phosphorus-containing compound contains no more than one --OH group
bonded to each phosphorus molecule.
24. The polyester composition of claim 22 wherein the
phosphorus-containing compound is selected from the group
consisting of trimethyl phosphate, triethyl phosphate, tributyl
phosphate, tributoxyethyl phosphate, tris(2-ethylhexyl) phosphate,
trioctyl phosphate, triphenyl phosphate, tritolyl phosphate,
ethylene glycol phosphate, triethyl phosphonoacetate, dimethyl
methyl phosphonate, and tetraisopropyl methylenediphosphonate.
25. The polyester composition of claim 22 wherein the
phosphorus-containing compound is selected from the group
consisting of the phosphate ester of group (1) wherein R.sub.1,
R.sub.2 and R.sub.3 are the same C.sub.1-C.sub.20 radical or a
combination of different C.sub.1-C.sub.20 radicals which optionally
include O, Cl or Br atoms and the phosphate ester of group (2)
wherein R is derived from a diol; R.sub.1, R.sub.2, R.sub.3 and
R.sub.4 are the same C.sub.1-C.sub.20 radical or a combination of
different C.sub.1-C.sub.20 radicals which optionally include O, Cl
or Br atoms.
26. The polyester composition of claim 25 wherein the
phosphorus-containing compound is selected from the group
consisting of trimethyl phosphate, triphenyl phosphate, tributyl
phosphate, trioctyl phosphate, tritolyl phosphate, tributoxyethyl
phosphate, ethylene glycol phosphate and tris(2-ethylhexyl)
phosphate.
27. The polyester composition of claim 25 wherein the phosphorus
containing compound has a molecular weight greater than about 300
g/mol.
28. The polyester composition of claim 22 wherein the
esterification catalyst or transesterification catalyst is selected
from the group consisting of titanium, calcium, barium, strontium,
chromium, zirconium and aluminum.
29. The polyester composition of claim 22 wherein the
polycondensation catalyst is selected from the group consisting of
titanium, germanium, zirconium and aluminum.
30. The polyester composition of claim 29 wherein esterification
catalyst or transesterification catalyst and the polycondensation
catalyst is titanium and the titanium is present in a molar ratio
of phosphorus to titanium of 0.2 to 2.4.
31. The polyester composition of claim 30 wherein the molar ratio
of phosphorus to titanium is 0.4 to 1.4.
32. The polyester composition of claim 22 wherein the phosphorus in
the form of a phosphorous-containing compound is added in an amount
of 1 to 310 ppm.
33. The polyester composition of claim 32 wherein the phosphorus in
the form of phosphorus-containing compound is added in an amount of
5 to 91 ppm.
34. The polyester composition of claim 22 wherein the diacid
component comprises residues of at least 90 mole percent
1,4-cyclohexanedicarboxyli- c acid.
35. The polyester composition of claim 34 wherein the diacid
component comprises residues of 100 mole percent of
1,4-cyclohexanedicarboxylic acid.
36. The polyester composition of claim 22 wherein residues of the
diacid component are derived from
1,4-dimethylcyclohexanedicarboxylate.
37. The polyester composition of claim 22 wherein the glycol
component comprises residues of at least 90 mole percent
1,4-cyclohexanedimethanol.
38. The polyester composition of claim 37 wherein the glycol
component comprises residues of 100 mole percent
1,4-cyclohexanedimethanol.
Description
RELATED INFORMATION
[0001] This application claims the benefit of U.S. Provisional
Application Serial No. 60/240,432 filed Oct. 13, 2000 titled
"Process for Producing Poly(1,4-cyclohexylenedimethylene
1,4-cyclohexanedicarboxylate) and the Reactor Grade Polyester
Therefrom".
TECHNICAL FIELD OF THE INVENTION
[0002] This invention relates to processes for the production of
poly(1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate and,
more particularly, to processes that have a reduced amount of
isomerization of dimethyl trans-1,4-cyclohexanedicarboxylate to
dimethyl cis-1,4-cyclohexanedicarboxylate and increased
polymerization rates through the addition of certain
phosphorus-containing compounds to the polymerization process.
BACKGROUND OF THE INVENTION
[0003] Polyesters of cycloaliphatic diacids and cycloaliphatic
diols were first disclosed in U.S. Pat. No. 2,891,930 to Caldwell
et al. and are useful in a number of applications, such as in
blends with polycarbonate, polyacrylate and other polyesters. U.S.
Pat. No. 5,486,562 to Borman et al. discloses blends of
poly(alkylene cyclohexanedicarboxylate) and amorphous copolymer
resins. U.S. Pat. No. 5,498,668 to Scott discloses blends of an
aliphatic or cycloaliphatic polyester with an acrylic polymer.
European Patent Application 0 902 052 A1 to Hoefflin et al.
discloses an aliphatic polyester-acrylic blend molding composition.
Compositions comprising a polycarbonate, a cycloaliphatic resin, an
ultraviolet light absorber and a catalyst quencher are disclosed in
U.S. Pat. No. 5,907,026, to Factor et al.
[0004] Cycloaliphatic polyesters are generally prepared by reacting
a cycloaliphatic diol, such as 1,4-cyclohexanedimethanol (CHDM),
and a cycloaliphatic diacid or its ester derivative, such as
1,4-dimethylcyclohexanedicarboxylate (DMCD), in a two-stage process
typical of linear polyesters. One such process is that described in
U.S. Pat. No. 2,465,319 to Whinfield et al. A useful polyester of
this type is poly(1,4-cyclohexylenedimethylene
1,4-cyclohexanedicarboxylate), hereafter referred to as PCCD.
[0005] In the first stage of the process for preparing PCCD, CHDM
and DMCD are reacted in the presence of a suitable catalyst to
effect an ester interchange reaction. Ester interchange is
typically carried out at temperatures ranging from 180 to
220.degree. C. Catalysts that can be used for ester interchange
include titanium, lithium, magnesium, calcium, manganese, cobalt,
zinc, sodium, rubidium, cesium, strontium, chromium, barium,
nickel, cadmium, iron and tin. Normal concentrations of catalyst
are in the range of 1 to 500 ppm. Most commonly, titanium is used
as the ester exchange catalyst for PCCD. Typically, low molar
ratios of diol to diester are used because of the difficulty in the
second stage of removing large excesses of high-boiling CHDM diol
during polycondensation. Thus, the degree of polymerization that
can be obtained in a reasonable length of time is limited (E. V.
Martin and C. J. Kibler, pp. 83-134, in "Man-Made Fibers: Science
and Technology", vol. III, edited by Mark, Atlas and Cernia, 1968).
A stoichiometric amount of diol to diester can be used, or if
appreciable amounts of the diester are lost due to volatilization,
a slight molar excess of the diester can be used. The reaction
product at the end of ester interchange in the first stage consists
of low molecular weight polymer with an average degree of
polymerization of about 2 to 10.
[0006] In the second stage, polycondensation is effected by
advancing the temperature to around 260 to 290.degree. C. and
applying a vacuum of 0.5 to 1.0 torr to aid in the removal of
reaction byproducts. Metals such as titanium, antimony, tin,
gallium, niobium, zirconium, aluminum, germanium or lead can be
used to catalyze polycondensation and are typically present in the
range of 1 to 500 ppm. Most commonly, titanium is used as the
polycondensation catalyst for PCCD. Polycondensation can also be
carried out in the solid phase. In this procedure, the
low-molecular prepolymer is isolated, solidified and granulated.
The solid prepolymer is then heated at a temperature about 20 to
40.degree. C. below its melting point under a vacuum or in the
presence of a flow of nitrogen.
[0007] CHDM and DMCD exist as both cis and trans geometric isomers.
The equilibrium concentration of isomers in DMCD is 65% trans and
35% cis. DMCD having a trans isomer content greater than the
equilibrium concentration can be produced by a number of processes,
such as the one described in U.S. Pat. No. 5,231,218 to Sumner et
al. For the most useful polymer properties, the starting DMCD used
to make PCCD should have a trans content greater than the
equilibrium amount of 65%. Preferably, the amount of trans isomer
in the starting DMCD monomer is greater than 98% by weight and the
amount of cis-isomer is less than 2% by weight. The starting CHDM
monomer as supplied typically contains 70% by weight of the
trans-isomer and 30% by weight of the cis-isomer. A high level of
trans units is desired because incorporation of cis-CHDM or
cis-DMCD units into the polymer chain disrupts the chain
regularity, lowers the melting point and reduces the amount of
crystallinity than can develop in the polymer, as described by
Wilfong in J. Polymer Sci., vol. 54, 385-410 (1961).
[0008] One disadvantage of the usual process for preparing PCCD is
that some of the trans-DMCD units isomerize to the cis-isomer
during the polymerization process, thus lowering the melting point
of the polymer and reducing the amount of crystallinity in the
polymer. The amount of isomerization of the trans-DMCD units that
occurs during the polymerization is dependent on several factors,
including catalyst type and concentration, reaction temperature and
residence time in the reactor. Processes that require a shorter
time in the reactor are desirable because there is less time
available for the trans-DMCD to undergo isomerization to the
cis-isomer. Normally there is no isomerization of the trans-CHDM
units during the polymerization process. FIG. 1 illustrates the
effect of cis-DMCD units in the polymer chain on the melting point
of PCCD. The melting point decreases by about 2.degree. C. for
every 1% increase in cis-DMCD units.
[0009] U.S. Pat. No. 5,939,519 to Brunelle describes the need for
higher crystallinity PCCD. The process requires incorporation of
amide segments at up to about 18 mole percent based on total ester
and amide segments into PCCD in order to increase the
crystallinity, which adds considerable cost to the polymer.
[0010] U.S. Pat. No. 6,084,055 to Brunelle discloses a method for
the preparation of poly(1,4-cyclohexane dicarboxylates) with
maximum molecular weight and crystallinity. The reaction is
conducted in a series of progressively increasing temperatures
below 265.degree. C. with a residence time in the range of 40 to
120 minutes at temperatures above 250.degree. C., and/or the
reaction is conducted with an initial stage of the reaction in the
presence of at least one C.sub.2-6 aliphatic diol. While
satisfactory results may be obtained using this method, the narrow
temperature range and residence time requirements are undesirable
because polymerization rates are limited.
[0011] U.S. Pat. No. 5,986,040 to Patel et al. discloses
crystalline PCCD resins in which the trans-cis ratio of repeating
units from DMCD in the polymer is greater than about 6 to 1, and
the trans-cis ratio of repeating units derived from CHDM is greater
than about 1 to 1 in the polymer. The polyester has a viscosity
greater than about 4200 poise and a melting temperature in the
range of about 216 to about 230.degree. C. A process to produce
this polymer is also disclosed. Patel teaches the importance of the
starting mole ratio of DMCD to CHDM to control the extent of
trans-to-cis isomerization of DMCD. The addition of phosphite
compounds to PCCD as color stabilizers is disclosed, although none
of the examples indicate that stablilizers were added.
[0012] U.S. Pat. No. 5,453,479 to Borman et al. discloses the use
of a polyesterification catalyst consisting of a phosphorus
compound and a titanium compound to prepare polyesters for blending
with polycarbonates. The process advantages are an increased in the
strength and mold cycle time of the blend.
[0013] The post-reaction addition of phosphite quenchers in blends
of polycarbonate, cycloaliphatic polyesters, and ultraviolet light
absorbers is disclosed in U.S. Pat. No. 5,907,026 to Factor et al.
The phosphite catalyst quencher is added in the post-reaction
blending of PCCD with other polymers.
[0014] Thus, there exists a need in the art for a fast, simple,
cost-effective process for preparing PCCD with a reduced level of
isomerization of the trans-DMCD units to cis-DMCD units.
Accordingly, it is to the provision of such process that the
present invention is primarily directed.
BRIEF SUMMARY OF THE INVENTION
[0015] In a process for producing a reactor grade polyester, a
poly(1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate) has
a reduced amount of isomerization of the trans-isomer to the
cis-isomer of 1,4-dimethylcyclohexanedicarboxylate and an increased
polymerization rate by the addition of a phosphorus-containing
compound to the reaction process. The process comprises the steps
of:
[0016] a) reacting a diacid comprising at least 80 mole percent
1,4-cyclohexanedicarboxylic acid or an ester derivative of the
diacid comprising at least 80 mole percent
1,4-dimethylcyclohexanedicarboxylate and a glycol comprising at
least 80 mole percent 1,4-cyclohexanedimethano- l at a temperature
sufficient to effect esterification for the diacid or
transesterification for the ester derivative;
[0017] b) polycondensing the product of step (a) at temperatures
and pressures in the presence of a suitable catalyst to effect
polycondensation;
[0018] c) adding 1 to 800 ppm phosphorus, wherein all parts by
weight are based on the weight of the polyester and the phosphorus
is added in the form of a phosphorus-containing compound; and
[0019] d) after step (c) removing a reactor grade polyester of
poly(1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate)
having an inherent viscosity of 0.4 to 2.0 dL/g.
[0020] The phosphorus-containing compound is selected from the
group consisting of: 1
[0021] (1) a phosphate ester having the formula:
[0022] wherein R.sub.1 is a hydrogen atom or a C.sub.1-C.sub.20
radical, which optionally includes O, Cl or Br atoms, and R.sub.2
and R.sub.3 are the same C.sub.1-C.sub.20 radical or a combination
of different C.sub.1-C.sub.20 radicals, which optionally include O,
Cl or Br atoms;
[0023] (2) a phosphate ester having the formula: 2
[0024] wherein R is derived from a diol; R.sub.1 and R.sub.4 can be
hydrogen atoms or C.sub.1-C.sub.20 radicals, which optionally
include O, Cl or Br atoms; and R.sub.2 and R.sub.3 are the same
C.sub.1-C.sub.20 radical or a combination of different
C.sub.1-C.sub.20 radicals, which optionally include O, Cl or Br
atoms;
[0025] (3) a diphosphate ester having the formula: 3
[0026] wherein R.sub.1 and R.sub.4 can be hydrogen atoms or
C.sub.1-C.sub.20 radicals, which optionally include O, Cl or Br
atoms, and R.sub.2 and R.sub.3 are the same C.sub.1-C.sub.20
radical or a combination of different C.sub.1-C.sub.20 radicals,
which optionally include O, Cl or Br atoms; and
[0027] (4) a phosphonate ester having the formula: 4
[0028] wherein R.sub.1 is a hydrogen atom or a C.sub.1-C.sub.20
radical, which optionally includes O, Cl or Br atoms, and R.sub.2
and R.sub.3 are the same C.sub.1-C.sub.20 radical or a combination
of different C.sub.1-C.sub.20 radicals, which optionally include O,
Cl or Br atoms.
[0029] Further, a reaction product polyester composition of
poly(1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate) is
produced having an inherent viscosity of 0.4 to 2.0 dL/g. The
polyester composition comprises a diacid component of residues of
at least about 80 mole percent of 1,4-cyclohexanedicarboxylic acid,
based on 100 mole percent diacid component; a glycol component of
residues of at least about 80 mole percent of
1,4-cyclohexanedimethanol, based on 100 mole percent glycol
component; 0 to 500 ppm esterification catalyst or 1 to 500 ppm
transesterification catalyst; 1 to 500 ppm polycondensation
catalyst, and 1 to 800 ppm phosphorus from a phosphorus-containing
compound as described above. All parts per weight are based on the
weight of the polyester.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is a graph of melting point versus percentage of
cis-DMCD units illustrating the effect of cis-DMCD units in the
polymer chain on the melting point of PCCD.
[0031] FIG. 2 is a graph of inherent viscosity versus
polycondensation time illustrating that the addition of phosphorus
in the form of a phosphate ester results in an increased
polycondensation rate.
[0032] FIG. 3 is a graph of inherent viscosity versus percentage of
cis-DMCD units illustrating that the addition of phosphorus in the
form of a phosphate ester results in increase inherent
viscosity.
DETAILED DESCRIPTION OF THE INVENTION
[0033] This invention relates to a process for the preparation of
poly(1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate)
(PCCD) having a reduced level of
cis-1,4-dimethylcyclohexanedicarboxylate (cis-DMCD) units in the
polymer chain and an increased polymerization rate. By the addition
of certain phosphorus-containing compounds to the process for
preparing PCCD from 1,4-cyclohexanedimethanol (CHDM) and
1,4-dimethylcyclohexane-dicarboxylate (DMCD), the amount of
isomerization of trans-DMCD units to cis-DMCD units is decreased
and the polymerization rate is increased. Controlling the
isomerization of trans-DMCD units is important to the process for
producing PCCD because any increase in cis-DMCD units results in a
lower melting point polymer and a reduction in the crystallinity of
the polymer.
[0034] The present invention is a process for producing a reactor
grade polyester of PCCD as distinguished from a blend of polymers
to produce the polyester. The reactor grade polyester thus produced
has an inherent viscosity of 0.4 to 2.0 dL/g and has repeat units
from a diacid component comprising repeat units from at least about
80 mole percent of 1,4-cyclohexanedicarboxylic acid and a glycol
component comprising repeat units from at least about 80 mole
percent of 1,4-cyclohexanedimethanol. The repeat units of
1,4-cyclohexanedicarboxylic acid (CHDA) can be derived from either
the acid itself or, preferably, its ester derivative of DMCD. The
mole percentages of the diacid component and the glycol component
are both based on 100 mole percent. In the process, the diacid
component and the glycol component are reacted at a temperature
sufficient to effect esterification when utilizing CHDA or
transesterification when utilizing DCMD. The reaction product of
the diacid component and glycol component is then subjected to
polycondensation at temperatures and pressures in the presence of a
suitable catalyst to effect polycondensation.
[0035] The distinguishing feature of the present invention is the
addition of phosphorus in the form of certain phosphorus-containing
compounds to the process for preparing PCCD. The phosphorus is
added in an amount of 1 to 800 parts per million (ppm), preferably
1 to 310 ppm and more preferably 5 to 91 ppm. The parts by weight
of the phosphorus added are the parts of the elemental phosphorus
and are based on the weight of the reactor grade polyester produced
by the process. However, the phosphorus is not added to the process
in its elemental form but rather added to the process in the form
of certain phosphorus-containing compounds. The
phosphorus-containing containing compounds used are selected from
the group consisting of the following:
[0036] (1) a phosphate ester having the formula: 5
[0037] wherein R.sub.1 is a hydrogen atom or a C.sub.1-C.sub.20
radical, which optionally includes O, Cl or Br atoms, and R.sub.2
and R.sub.3 are the same C.sub.1-C.sub.20 radical or a combination
of different C.sub.1-C.sub.20 radicals, which optionally include O,
Cl or Br atoms;
[0038] (2) a phosphate ester having the formula: 6
[0039] wherein R is derived from a diol; R.sub.1 and R4 can be
hydrogen atoms or C.sub.1-C.sub.20 radicals, which optionally
include O, Cl or Br atoms; and R.sub.2 and R.sub.3 are the same
C.sub.1-C.sub.20 radical or a combination of different
C.sub.1-C.sub.20 radicals, which optionally include O, Cl or Br
atoms;
[0040] (3) a diphosphate ester having the formula: 7
[0041] wherein R.sub.1 and R.sub.4 can be hydrogen atoms or
C.sub.1-C.sub.20 radicals, which optionally include O, Cl or Br
atoms, and R.sub.2 and R.sub.3 are the same C.sub.1-C.sub.20
radical or a combination of different C.sub.1-C.sub.20 radicals,
which optionally include O, Cl or Br atoms; and
[0042] (4) a phosphonate ester having the formula: 8
[0043] wherein R.sub.1 is a hydrogen atom or a C.sub.1-C.sub.20
radical, which optionally includes O, Cl or Br atoms, and R.sub.2
and R.sub.3 are the same C.sub.1-C.sub.20 radical or a combination
of different C.sub.1-C.sub.20 radicals, which optionally include O,
Cl or Br atoms.
[0044] Preferably, the phosphorus-containing compound is selected
from the phosphate ester of group (1) above wherein R.sub.1,
R.sub.2 and R.sub.3 are the same C.sub.1-C.sub.20 radical or a
combination of different C.sub.1-C.sub.20 radicals, which
optionally include O, Cl or Br atoms, or the phosphate ester of
group (2) wherein R is derived from a diol; R.sub.1, R.sub.2,
R.sub.3 and R.sub.4 are the same C.sub.1-C.sub.20 radical or a
combination of different C.sub.1-C.sub.20 radicals, which
optionally include O, Cl or Br atoms.
[0045] Specific examples of phosphorus compounds that can be used
in this invention include, but are not limited to, trimethyl
phosphate, triethyl phosphate, tributyl phosphate, tributoxyethyl
phosphate, tris(2-ethylhexyl) phosphate, trioctyl phosphate,
triphenyl phosphate, tritolyl phosphate, ethylene glycol phosphate,
triethyl phosphonoacetate, dimethyl methyl phosphonate,
tetraisopropyl methylenediphosphonate, and Merpol A.
[0046] The phosphorus-containing compound preferably contains no
more than one --OH group bonded to each phosphorus molecule because
the polycondensation rate is faster as compared to the
polycondensation rate when more than one --OH group is directly
bonded to phosphorus.
[0047] The phosphorus-containing compound can be added anytime
during the process. Preferably, the phosphorus-containing compound
is added before or after the reaction of the diacid component and
glycol component because a faster polycondensation rate is
achieved. More preferably, the phosphorus-containing compound is
added before the esterification or transesterification reaction
because the polycondensation rate is fastest when the
phosphorus-containing compound is added at this point.
[0048] For esterification, a catalyst may or may not be utilized.
The amount of esterification catalyst is from 0 to 500 ppm,
preferably 10 to 200 ppm, more preferably 20 to 100 ppm. For
transesterification, the presence of a sufficient amount of a
transesterification catalyst is required at an amount of 1 to 500
ppm, preferably 10 to 200 ppm, more preferably 20 to 100 ppm.
Examples of esterification or transesterification catalysts that
can be used are manganese, zinc, magnesium, calcium, titanium,
silver, molybdenum, gold, cobalt, nickel, potassium, sodium,
lithium, rubidium, cesium, strontium, barium, copper, silver,
mercury, tin, cadmium, bismuth, aluminum, chromium, zirconium, iron
and lead. Preferably, such catalyst does not increase the amount of
isomerization of trans-DMCD units during the formation of the
polymer to counter the effect of the addition of phosphorus or
appreciably increase the yellowness or darkness of the polymer. For
this reason, esterification and transesterification catalysts such
as titanium, calcium, strontium, chromium, zirconium and aluminum
are preferred.
[0049] Polycondensation catalysts are present in an amount of 1 to
500 ppm, preferably 5 to 200 ppm and more preferably 20 to 100 ppm.
Suitable polycondensation catalysts preferably include titanium,
germanium, zirconium and aluminum because they do not increase the
amount of trans-DMCD isomerization or negatively impact the
polymer's color.
[0050] Similar to phosphorus, the esterification,
transesterification and polycondensation catalysts are not added to
the process in their elemental form but rather added as
metal-containing compounds well known in the art. The parts by
weight of the metals added are the parts of the elemental metal and
are based on the weight of the reactor grade polyester produced by
the process.
[0051] The most preferred catalyst for the present invention is
titanium utilized both as the esterification or transesterification
catalyst and the polycondensation catalyst. The preferred molar
ratio of phosphorus from the phosphorus-containing compound to
titanium is about 0.2 to 2.4. More preferably, the ratio is about
0.4 to 1.4. Examples of titanium-containing compounds that can be
used are, but not limited to, tetraisopropyl titanate, acetyl
triisopropyl titanate, tetrabutyl titanate, titanium diisopropoxide
bis (2,4-pentanedionate), and tetrakis(2-ethylhexyl)
orthotitanate.
[0052] The diacid component of the PCCD polyester comprises repeat
units from at least about 80 mole percent, preferably 90 mole
percent, and more preferably 100 mole percent, of CHDA. The diacid
component of the PCCD polyester may be optionally modified with up
to about 20 mole percent, preferably 10 mole percent, of one or
more dicarboxylic acids. Such modifying dicarboxylic acids include
aromatic dicarboxylic acids preferably having 8 to 14 carbons or
their ester derivatives, aliphatic dicarboxylic acids preferably
having 4 to 12 carbon atoms or their ester derivatives, and
cycloaliphatic dicarboxylic acids having 8 to 12 carbons or their
ester derivatives. Examples of dicarboxylic acids which could be
used as modifiers include terephthalic acid; phthalic acid;
isophthalic acid; napthalene-2,6-dicarboxylic acid;
cyclohexanediacetic acid; diphenyl-4,4'-dicarboxylic acid; succinic
acid; glutaric acid; adipic acid; azealic acid; and sebacic acid.
Ester derivatives of these acids may be used in the process of
preparing the PCCD polyester.
[0053] The glycol component of the PCCD polyester comprises repeat
units from at least about 80 mole percent, preferably 90 mole
percent, more preferably 100 mole percent, of CHDM. The glycol
component of the polyester may be optionally modified with up to
about 20 mole percent, preferably 10 mole percent, of one or more
diols. Such modifying diols include cycloaliphatic diols preferably
having 6 to 20 carbons, aliphatic diols preferably having 3 to 20
carbon atoms, and polyether glycols. Examples of such diols are
ethylene glycol, diethylene glycol; triethylene glycol;
propane-1,3-diol; butane-1,4-diol; pentane-1,5-diol;
hexane-1,6-diol; neopentyl glycol;
2,4-dihydroxy-1,1,3,3-tetramethylcyclo- butane; and
poly(tetramethylene ether glycol).
[0054] Furthermore, the PCCD polyester may contain small amounts
(less than 1 weight percent based on the weight of the polyester)
of trifunctional or tetrafunctional comonomers such as trimellitic
anhydride, trimethylolpropane, pyromellitic dianhydride,
pentaerythritol and other polyester-forming polyacids or polyols
generally known in the art.
[0055] In another embodiment, the present invention is a reaction
product polyester composition of PCCD having an inherent viscosity
(IV) of 0.4 to 2.0 dL/g, preferably 0.8 to 1.2 dL/g. IV is measured
at 25.degree. C. using a polymer concentration of 0.5 wt % in a
solvent consisting of 60% phenol and 40% 1,1,2,2-tetrachlorethane.
The reaction product polyester composition comprises a diacid
component of residues of at least about 80 mole percent of
1,4-cyclohexanedicarboxylic acid, based on 100 mole percent diacid
component; a glycol component of residues of at least about 80 mole
percent of 1,4-cyclohexanedimethanol, based on 100 mole percent
glycol component; 0 to 500 ppm esterification catalyst or 1 to 500
ppm transesterification catalyst; 1 to 500 ppm polycondensation
catalyst, and 1 to 800 ppm phosphorus in the form of the
phosphorus-containing compound described above; all parts per
weight based on the weight of the polyester. The preferred
embodiments related to the process described above are applicable
to the reaction product polyester composition.
[0056] 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
[0057] This example illustrates the effect of the phosphate ester,
triphenyl phosphate, on the properties of PCCD. To a 500-milliliter
(mL) roundbottom flask was charged 100.1 grams (g) (0.4 moles)
dimethylcyclohexane dicarboxylate (DMCD), 72.1 g (0.4 moles)
1,4-cyclohexanedimethanol (CHDM) and 70 parts per million (ppm)
titanium as titanium (IV) isopropoxide. The DMCD starting material
was analyzed to contain 98.5 weight percent (wt %) trans-isomer and
1.5 wt % cis-isomer. The CHDM monomer contained 70 wt %
trans-isomer and 30 wt % cis-isomer. After charging the reactants,
the flask was connected to a polymerization reactor that was
equipped with an overhead stirrer, nitrogen inlet, condensing flask
and vacuum source. A molten bath of Belmont metal preheated to
185.degree. C. was raised to surround the flask. The Belmont metal
bath temperature was increased from 185.degree. C. to 220.degree.
C. over a 30-minute period with a slow stream of nitrogen bleeding
into the system. The reaction was stirred at a speed of 100
rotations per minute (rpm). The temperature was held at 220.degree.
C. for 30 minutes to complete the ester exchange reaction period.
At this stage, 50 ppm phosphorus as triphenyl phosphate was added
to the flask through the nitrogen port. The temperature was then
increased to 270.degree. C. over a 25-minute period. After stopping
the nitrogen flow, the pressure was reduced from atmospheric
pressure to 0.5 torr and the stir speed slowed from 100 rpm to 20
rpm over a ten-minute period. The polycondensation reaction was
continued under these conditions for five hours. At the completion
of the reaction, the flask was removed from the Belmont metal bath
and the polymer cooled under a nitrogen atmosphere. The polymer was
recovered from flask and ground in a Wiley mill to a particle size
of about 6 mm. The inherent viscosity (IV) was measured at
25.degree. C. using a polymer concentration of 0.5 wt % in a
solvent consisting of 60 wt % phenol and 40 wt %
1,1,2,2-tetrachlorethane. Polymer yellowness and brightness were
measured with a Hunter Ultrascan instrument and reported in CIELAB
units. Titanium and phosphorus concentrations were measured by
x-ray fluorescence. The amount of cis-DMCD units in the polymer was
obtained by nuclear magnetic resonance spectroscopy.
Example 2
[0058] This example illustrates the effect of the phosphate ester,
Merpol A, on the properties of PCCD. Merpol A is commercially
available from Stepan, Co. The procedure of Example 1 was followed,
except that 18 ppm phosphorus from Merpol A was added to the flask
instead of triphenylphosphate.
Example 3
[0059] This example illustrates the effect of phosphoric acid on
the properties of PCCD. The procedure of Example 1 was used, except
that 49 ppm phosphorus from phosphoric acid was added instead of
triphenylphosphate.
Comparative Example 1
[0060] This example illustrates the properties of PCCD without any
phosphate compound added. The procedure of Example 1 was followed,
except that no phosphorus compound was added.
Example 4
[0061] This example shows the effect of the phosphite stabilizer,
distearyl pentaerythritol diphosphite (Weston 619), on the
properties of PCCD. The procedure of Example 1 was used, except
that 31 ppm phosphorus from Weston 619 was added instead of
triphenylphosphate.
Example 5
[0062] This example also shows the effect of a phosphite stabilizer
on PCCD properties. The procedure of Example 4 was used, except
that 43 ppm phosphorus from the phosphite
bis(2,4-di-tertbutylphenyl) pentaerythritol diphosphite (Ultranox
626) was added instead of Weston 619.
Example 6
[0063] This example illustrates the effect of phosphorous acid
(H.sub.3PO.sub.3) on the properties of PCCD. The procedure of
Example 4 was used, except that 43 ppm phosphorus from phosphorous
acid was added instead of Weston 619.
Comparative Example 2
[0064] This example shows the properties of PCCD made without any
phosphite added. The procedure of Example 4 was followed, except
that no phosphite was added.
[0065] The results for Examples 1 through 3 and Comparative Example
1 in Table 1 illustrate the effect of phosphate esters on the
properties of PCCD. The addition of a phosphate ester to the
reaction process decreases the amount isomerization of trans-DMCD
to the cis isomer. The results also show that the addition of
phosphate esters produced polymer with a higher IV than the
control, whereas the addition of phosphoric acid decreased the
polymer IV. This indicates that the polymerization rate is slowed
when a phosphorus compound with a high number of acidic --OH groups
bonded to phosphorus is used. A slower polymerization rate is not
desired because it increases the amount of time needed in the
polymerization reactor to reach the targeted polymer IV, thus
increasing the amount of time available for the trans-to-cis
isomerization of DMCD. Therefore, the use of neutral phosphorus
compounds is preferred over those that contain a high number of
acidic --OH groups bonded to phosphorus.
[0066] Examples 4 through 7 and Comparative Example 2 in Table 1
illustrate the effect of phosphites on the on the properties of
PCCD. These compounds have the following general structure: 9
[0067] where R1, R2 and R3 are selected from the group of alkyl,
aryl or hydrogen substituents. These compounds are different from
phosphates in the oxidation state of phosphorus. The oxidation
state of phosphorus in phosphites is +3, compared to +5 in
phosphates. The data show that although the use of phosphites in
PCCD retards the amount of trans-to-cis-isomerization of DMCD, the
use of phosphites also undesirably slows the polycondensation rate
as indicated by the lower polymer IV. This is not a desirable
effect because the required residence time in the reactor is
increased to reach the desired polymer IV and allows more time for
trans-to-cis isomerization to occur. Therefore, the use of neutral
or acidic phosphite compounds to reduce isomerization in PCCD is
not preferred.
Examples 7-13
[0068] The procedure of Example 2 was used except the phosphorus
level from the phosphate ester Merpol A was varied from 17 to 114
ppm.
Comparative Example 3
[0069] The procedure of Examples 7 through 13 was used except no
Merpol A was added.
[0070] The results for examples 7-13 and Comparative Example 3 are
given in Table 2. Examples 7 to 13 illustrate the optimum P/Ti
molar ratio when using a phosphate ester phosphorus source. The
highest polymer IV and lowest cis-DMCD content occur at P/Ti molar
ratios between about 0.4 and 1.4. At P/Ti molar ratios greater than
about 2.4, there is a significant drop in polymer IV. Therefore,
P/Ti molar ratios less than 2.4 are preferred and furthermore,
molar ratios of about 0.4 to 1.4 are most preferred.
Examples 14-25
[0071] The procedure of Example 1 was used except that a
co-catalyst was added to the reaction flask in addition to the 70
ppm titanium as titanium (IV) isopropoxide. In Example 14, 50 ppm
lithium as lithium acetate was added. In Example 15, 50 ppm sodium
as sodium acetate was added. In Example 16, 50 ppm rubidium as
rubidium acetate was added. In Example 17, 50 ppm cesium as cesium
acetate was added. In Example 18, 50 ppm strontium as strontium
acetate was added. In Example 19, 50 ppm manganese as manganese
acetate was added. In Example 20, 50 ppm nickel as nickel acetate
was added. In Example 21, 50 ppm cadmium as cadmium acetate was
added. In Example 22, 50 ppm tin as dibutyltin diacetate was added.
In Example 23, 50 ppm chromium as chromium (III) acetate was added.
In Example 24, 50 ppm silver as silver acetate was added. In
Example 25, 50 ppm molybdenum as molybdenum acetate was added.
Comparative Example 4
[0072] This example illustrates the properties of PCCD without any
co-catalyst added. The method of Examples 14 to 25 was followed,
except no co-catalyst was added.
Examples 26-31
[0073] The procedure of Examples 14 to 25 was used to evaluate
additional co-catalysts with titanium. In Example 26, 50 ppm
calcium as calcium acetate was added. In Example 27, 50 ppm lead as
lead (II) acetate was added. In Example 28, 50 ppm germanium as
germanium dioxide was added. In Example 29, 50 ppm antimony as
antimony (III) oxide was added. In Example 30, 50 ppm magnesium as
magnesium acetate was added. In Example 31, 50 ppm gold as gold
(III) acetate was added.
Comparative Example 5
[0074] This example was carried out to determine the properties of
PCCD without co-catalyst. The process of Examples 26-31 was
followed but no co-catalyst was added.
Examples 32-35
[0075] These examples followed the same process for Examples 14 to
25, except different co-catalysts were evaluated. In example 32, 50
ppm zinc as zinc acetate was added. In example 33, 50 ppm cobalt as
cobalt acetate was added. In example 34, 50 ppm barium as barium
acetate was added. In example 35, 50 ppm aluminum as aluminum
acetate was added.
Comparative Example 6
[0076] The method for Examples 32 to 35 was carried out for
Comparative Example 6, except no co-catalyst was added.
Examples 36-39
[0077] These examples followed the procedure of Examples 14-25
except that different co-catalysts were evaluated. In Example 36,
50 ppm bismuth as bismuth acetate was added. In Example 37, 50 ppm
zirconium as zirconium isopropoxide was added. In Example 38, 50
ppm copper was added as copper (II) acetate. In Example 39, 50 ppm
iron was added as iron (III) acetate.
Comparative Example 7
[0078] The same procedure for Examples 36-39 was followed but no
co-catalyst was added.
[0079] The results of Examples 15 to 39 in Table 3 illustrate the
effect of co-catalysts in conjunction with titanium on the polymer
properties and the amount of trans-to-cis-isomerization of DMCD.
Lithium, sodium, rubidium, cesium, manganese, nickel, cadmium, tin,
molybdenum, lead, magnesium, gold, zinc, cobalt and iron
co-catalysts all resulted in higher levels of cis-DMCD units in the
polymer than the control and are therefore not preferred to make
PCCD with a low level of trans-DMCD units. Calcium, germanium,
strontium and zirconium co-catalysts had very little or no effect
on the amount of DMCD isomerization. Antimony, barium, chromium,
copper, bismuth, silver and aluminum all resulted in a lower amount
of cis-DMCD units in the polymer than the control. However, the
polymers made with bismuth, copper, silver and antimony catalysts
were unacceptably dark (low L*) compared to the control, presumably
due to reduction of the ion to its metallic state. Therefore, the
preferred co-catalysts are aluminum, barium, zirconium, strontium,
chromium, calcium and germanium, which do not increase the level of
trans-to-cis DMCD isomerization and give polymer with acceptable
color.
Example 40
[0080] The method of Example 1 was used except that a two-neck
roundbottom was used which was equipped with a sampling device in
order to remove samples from the reaction while the flask remained
under vacuum. No phosphate compound was added to the flask. Samples
were removed approximately every thirty minutes during the final
polycondensation stage. The samples were analyzed for IV and
cis-DMCD units.
Example 41
[0081] The method of Example 40 was used except that 70 ppm P as
the phosphate ester Merpol A was added before the start of the
ester exchange stage.
Example 42
[0082] The method of Example 40 was used except that 70 ppm P as
the phosphate Merpol A was added after the completion of the ester
exchange stage.
[0083] The results of Examples 40 to 42 are plotted in FIGS. 2 and
3, which illustrate the effect of the phosphate ester Merpol A on
the polycondensation rate and the cis-DMCD content. The data in
FIG. 2 show that the addition of the Merpol A phosphate ester
compound either before or after the ester exchange period leads to
a faster polycondensation rate. The results further show that the
polycondensation rate is faster when the phosphate compound is
added at the start of the ester exchange period. In FIG. 3, IV is
plotted against cis-DMCD units for Examples 40 to 42. This plot
illustrates the beneficial effect of the phosphate ester compound
on the amount of cis-DMCD units formed in the polymer. A higher IV
and lower amount of cis-DMCD isomer are obtained when the phosphate
ester is added. Further, it illustrates that the most beneficial
feed location of the phosphate ester is before the ester exchange
period.
1TABLE 1 Evaluation of Phosphorus Additives in PCCD Phosphorus Cis-
Oxidation IV DMCD Ti Molar Example Phosphorus Source State (dL/g)
(%) (ppm) P (ppm) ratio P/Ti 1 Triphenyl phosphate +5 1.012 5.17 70
52 1.1 2 Merpol A +5 1.025 5.35 70 18 0.4 3 Phosphoric Acid +5
0.755 5.05 70 49 1.1 Comparative 1 None 0.956 6.80 69 0 0 4 Weston
619 +3 0.718 5.02 72 31 0.66 5 Ultranox 626 +3 0.937 5.23 73 43
0.90 6 Phosphorous Acid +3 0.846 5.11 66 43 1.0 Comparative 2 None
1.056 6.68 70 0 0
[0084]
2TABLE 2 Effect of P/Ti Molar Ratio on PCCD Properties Using Merpol
A Phosphate Ester IV cis-DMCD Ti P molar ratio Example (dL/g) (%)
(ppm) (ppm) P/Ti 7 1.000 5.02 72 17 0.4 8 1.021 4.51 72 35 0.8 9
0.989 4.44 74 51 1.1 10 0.918 4.35 74 66 1.4 11 0.727 4.50 73 86
1.8 12 0.571 3.78 74 102 2.1 13 0.406 3.22 73 114 2.4 Comparative 3
0.931 5.66 72 0 0
[0085]
3TABLE 3 Evaluation of Co-Catalysts in PCCD IV cis-DMCD Ti Example
Co-catalyst (dL/g) b* L* (%) (ppm) 14 Li 0.971 7.3 79.5 28.62 61 15
Na 0.990 7.5 83.7 16.43 62 16 Rb 1.002 7.8 83.9 16.77 68 17 Cs
0.970 7.5 82.8 18.79 67 18 Sr 1.093 5.7 85.0 5.96 67 19 Mn 1.043
10.2 82.8 11.69 63 20 Ni 1.066 4.5 71.0 6.43 69 21 Cd 1.009 6.2
86.0 7.80 70 22 Sn 1.000 8.9 83.8 14.84 66 23 Cr 0.975 3.6 83.9
4.92 73 24 Ag 1.000 30.1 72.1 5.24 67 25 Mo 1.040 7.7 72.5 12.55 66
Comp. 4 None 0.911 4.5 86.2 5.54 67 26 Ca 1.043 6.4 85.6 6.91 63 27
Pb 1.075 6.9 77.6 15.37 66 28 Ge 1.046 6.0 84.4 6.88 64 29 Sb 1.077
1.3 71.8 6.03 68 30 Mg 1.108 9.8 83.4 13.51 63 31 Au 0.993 -1.2
74.9 9.72 71 Comp. 5 None 1.049 7.0 85.1 6.68 69 32 Zn 1.041 4.8
85.9 9.35 63 33 Co 0.909 1.7 77.7 9.64 66 34 Ba 0.871 3.5 88.8 5.36
63 35 Al 0.949 3.3 88.8 5.09 66 Comp. 6 None 1.056 4.8 87.6 6.68 70
36 Bi 1.305 2.3 78.0 6.42 66 37 Zr 1.068 4.9 87.5 7.00 66 38 Cu
0.958 1.5 57.4 5.97 65 39 Fe 1.004 9.3 75.4 16.46 65 Comp. 7 None
0.956 4.6 88.6 6.80 69
* * * * *