Note: Descriptions are shown in the official language in which they were submitted.
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POLY(ALKYLENE ARYLATES) HAVING OPTICAL PROPERTIES
BACKGROUND OF INVENTION
s FIELD OF INVENTION
This invention relates to poly(alkylene arylates), such as polyethylene
terephthalate), PET; polypropylene terephthalate), PPT; poly(butylene
terephthalate), PBT; polyethylene naphthalate), PEN; polypropylene
napthalate),
PPN; poly(butylene naphthalate); polyethylene isophthalate), PEI;
polypropylene
to isophthalate), PPI; poly(butylene isophthalate), PBI; homopolymers and
their
copolymers and mixtures, containing the residue of organic titanate-ligand
catalyst
systems. The poly(alkylene arylate)s possess better optical properties than
similar
polymers heretofore made with other organic titanate-ligand catalysts.
Resulting
PET, for example, is particularly useful in preparing transparent articles,
such as
is films, that have excellent clarity, reduced light scattering and absorb
less light than
conventional PET. Thus, PET resins made with the catalyst have particular
utility
as the substrate for x-ray and photographic films.
DESCRIPTION OF RELATED ART
Polyethylene terephthalate), PET, is a widely used polyester typically
2o manufactured by two routes: (1) transesterification of a dialkyl
terephthalate ester
(e.g., dimethyl terephthalate) with ethylene glycol to form an intermediate
bis-2-
hydroxyethyl terephthaIate, followed by polycondensation to form the PET; or,
(2)
by direct esterification of terephthalic acid with ethylene glycol, followed
by
polycondensation to form PET. A catalyst is commonly used to speed the
reaction
2s in either case. The same or different catalyst may be selected for the
transesterification and polycondensation steps.
Many commercial processes use manganese or zinc salts as the catalyst for
the transesterification step. Antimony, in the form of a glycol solution of
antimony
oxide, typically is used as the polycondensation catalyst in either the
3o transesterification or direct esterification processes outlined above.
There is an
interest in replacing antimony with another catalyst, however, since insoluble
antimony species tend to be formed which increase the polymer darkness,
scatter
light, and interfere with spinning or other forming. Furthermore, antimony
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catalysts have come under increasing regulatory pressure. Thus, there is a
need for
new polycondensation catalysts that reduce or replace antimony in the
manufacture
of PET and other poly(aikylene arylate)s.
Organic titanates, such as tetraisopropyl and tetra n-butyltitanates, are
s known to be effective polycondensation catalysts for preparing poly(alkylene
arylates) in general, and frequently are the catalyst of choice in the
manufacture of
polybutylene terephthalate (PBT) because of their higher reactivity than
conventional antimony catalysts. Organic titanates are not generally used in
the
manufacture of PET, however, because residual titanate catalyst tends to react
o with trace impurities formed during the polycondensation and processing of
PET
(e.g., aldehydes), generating yellow discoloration that cannot be tolerated in
products typically fabricated from PET (e.g., x-ray and photographic films,
bottles,
and packaging film).
Lack of glycol solubility also is a practical limitation for most organic
15 titanate catalysts. It is preferred to add catalyst to a continuous
polycondensation
reaction as a dilute glycol solution (rather than a dispersion) to obtain
uniform
distribution of the small quantities of catalyst that are employed. Organic
titanates
typically form a precipitate when added to a glycol, which tends to complicate
manufacturing control and introduces product quality problems due to non-
2o uniform distribution of catalyst in the reaction mass.
Numerous binary compositions containing organic titanates and
phosphorus compounds (organic and inorganic) have been proposed in the
technical and patent literature for use as a polycondensation catalyst in the
manufacture of poly(alkylene arylates). For example, it has been proposed to
add
25 phosphoric acid, or other phosphorus based compounds, along with organic
titanates to control color by complexing the residual titanate catalyst. The
use of
such strong complexing agents, however, invariably reduces efficiency of the
titanate catalyst and introduces polymerization control problems. Thus, there
is an
ongoing need for a non-antimony based polycondensation catalyst that is glycol-
3o soluble, efficient, and produces poly(alkylene arylates) in general, and
PET and
PPT in particular, having excellent optical properties.
SUMMARY OF THE INVENTION
The present invention provides a more useful and attractive form of
poly(alkylene arylates), such as PET and PPT, that are polymerized using an
35 organic titanate-ligand catalyst. The polymer has low visible reflective
color and
r
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can be either pressed, extruded or otherwise formed into an article, such as a
film,
in a way such that the article has high light transmissivity between
wavelengths
320 nm and 800 nm. The polymer can be prepared using an organic titanate-
ligand
catalyst system that can ( 1 ) be soluble in the reaction mixture, (2) be
soluble in the
alcohol used in preparing the polymer, (3) provide high rates of
polymerization in
the reaction mixture, (4) include cocatalysts or supplementary additives to
the
polymer which help prevent the formation of titanate chromophores, or (5)
prevent
or greatly reduce the formation of chromophores. The term "organic titanate-
ligand catalyst" as used herein refers to a catalyst deriveable from or
containing an
organic ortho titanate with ligands and cocatalysts that may prevent the
formation
of titanate chromophores, such cocatalysts can comprise organic silicates,
organic
zirconates and organic phosphors.
DETAILED DESCRIPTION OF THE INVFN'TTON
The poly(alkylene arylate) polymer of the present invention can be a
homopolymer or a copolymer. The term " poly(alkylene arylate) " is referred to
a
polymer having repeat units derived from at least one methylenic monomer or
comonomer containing aromatic carboxylic group. The term "copolymer" used
herein include a polymer comprising repeat units derived from two or more
comonomers. Any comonomers containing a polymerizable ethylenic structure
2o such as, for example, ethylene, propylene, hexene, decene, can be used to
produce
the polymer.
Organic titanates are well known to promote rapid polycondensation rates
in the preparation of poly(alkylene arylates). Organic titanates are generally
not
used commercially for this purpose when optical properties are important such
as
in many of the commercial products fabricated from PET, PEI, PPT, and PBT,
however, because the organic titanates tend to cause unacceptable color
formation
and light absorption. While this invention applies generally to poly(alkylene
arylates), it now will be described in detail with respect to PET, a preferred
embodiment.
3o Without being bound by theory, degradation by-products inevitably are
produced in small quantities during the polymerization and processing of PET.
These by-products (e.g., aldehydes, especially acetaldehyde) form chemical
complexes with catalyst residues (i.e., titanates) that generate discoloration
in, and
absorb light passing through, the PET. Thus, the PET is not suitable for
consumer
applications because it is not attractive, or for applications such as
photographic or
x-ray film substrates because the complexes detract from desired image
resolution
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and imaging sensitivity. These optical properties include two phenomena: (1)
how
the PET reflects light; and (2) how PET absorbs light being transmitted
through it.
The organic titanate-ligand catalyst decreases or eliminates the combination
of the organic titanate with polymerization by-products (e.g., aldehydes),
thereby
reducing or eliminating absorbance of light in the polymer at ultraviolet and
visible
wavelengths of 320 nm to 800 nm. Without being bound by theory, the ligand(s)
prevents) the formation of titanium complexes that detract from desired
optical
properties, and/or forms complexes with the by-products that do not detract
from
the desired optical properties. The organic titanate-ligand catalyst system
may
include a cocatalyst which provides alternative sites for the by-products and
the
combined cocatalyst and by-products are not chromophores.
According to the present invention, the poly(alkylene arylate) has a weight
average molecular weight of at least 21,000 Daltons and containing between 0.1
and 500 ppm organic titanium-ligand catalyst residue. The poly(alkylene
arylate)
can have an ABS/L value from 0 to less than or equal to 6.1, preferably less
than
or equal to 6, and more preferably less than or equal to 5, and even more
preferably less than or equal to 4. The polymer can have a Hunter L value
greater
than 65, preferably greater than 75, a Hunter a value between -2 and +2,
preferably about zero, and a Hunter b_ value between -2 and 6, preferably
about
2o zero. Alternatively, the polymer can have a combination of a weight average
molecular weight of at least about 21,000 containing about 0.5 to 500 ppm
titanium residue from an organic titanate-ligand catalyst solution, an ABS/L
value
of less than 7, a Hunter L greater than 65, a Hunter a value between -Z and
+2, and
a Hunter b value between -2 and 8.3. Further alternatively, the polymer can
have
the combination of a weight average molecular weight of at least about 21,000
and
containing between 0.5 to 500 ppm titanium catalyst residue, an ABS/L value
less
than 7, a Hunter L greater than 65, a Hunter a value between -2 and +2, and a
Hunter b value between -2 and 6.The catalyst residue (between 0.1 and 500 ppm)
refers to the presence of elemental titanium in parts per weight per million
parts by
3o weight polymer, and does not include any particulate titanium dioxide
compounds
that may be present for other reasons. Quantity of titanium catalyst residue
is
conveniently determined by elemental analysis or spectroscopy.
REFLECTED LIGHT
Polymer color conventionally is evaluated by measuring the intensity of
light reflected at various wavelengths when the polymer is exposed to a broad-
spectrum light source using an instrument such as a spectrophotometer. The
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techniques generally are described in The Measurement of Appearance,
R. S. Hunter and R. W. Harold, 2"d ed., Wiley Publishers, New York (1987); and
Color Science: Concepts and Methods. Quantitative Data and Formulae,
G. Wyszecki and W. S. Stiles, 2"d ed., Wiley Publishers, New York (1982).
Color
can be measured and reported by specifying the three numerical values of L, a
and
b in the Hunter color scale. The L-value represents whiteness or shade of
gray; the
greater the numerical value, the higher the whiteness. The L-scale's upper
limit is
100 which denotes white in the absence of hue and the L-scale's lower limit is
zero
which denotes black. The a and b values indicate the intensity of hue or tint.
1o When both a and b values are zero the material is a shade of gray, or is
said to have
neutral hue. A positive value of a denotes redness and a negative value of a
denotes greenness. A positive value of b denotes yellowness and a negative
value
of b denotes blueness.
The physical form of the polyethylene terephthalate) polymer influences
the numerical values of the L, a and b color numbers as measured by a
spectrophotometer in reflectance mode. Polymer in the form of thin fiber or
small
powder particle size or rough surface shape reflects more light than
respective
thicker fiber or large powder particle size or smooth surface. Thus a sample
of the
former shape type will have higher whiteness and more neutral hue than a
sample
of the latter shape type if the chemical composition of the samples is
identical.
Crystalline polymer reflects more light than less crystalline or amorphous
polymer.
Thus a more crystalline sample will have a higher whiteness and more neutral
hue
than a more amorphous sample if the chemical composition of the samples is
identical. Thus when comparing the reflected color of polymer samples which
differ by catalyst composition, it is useful to ensure the physical shape and
form are
very similar to assess the advantages of particular catalyst systems.
A color measurement method may capture only light reflected from the
polymer or a measurement can capture light which is both reflected from and
transmitted through the polymer. Examples of the former case includes incident
light reflected from the surface of polymer fibers or ground polymer flakes or
powder particles. Examples of the latter case includes light which is incident
on a
stack of films such that some of the light reflects directly from the outer
surface of
the first film while some light transmits through some layers and are
reflected out
of the films by interior interfaces within the film stack. The latter color
measurement method is not preferred by the inventors because some light
wavelengths can be absorbed and/or transmitted by the polymer, thus the L, a,
b
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values do not provide a pure indication of the colored light only reflected by
the
polymer surface.
Hunter color values recited herein are determined in accordance with the
following procedure, as illustrated in the Examples. A specific sample
preparation
is used to measure and compare reflective color from several PET samples
differing by catalyst composition. A PET sample is first crystallized to at
least
20 weight percent crystallinity, typically 30 weight percent, by annealing in
an oven
at 160°C for 16 hours. Then the sample is ground to a fine, uniform
powder using
a Wiley Mill grinder (model ED-5 obtained through Thomas Scientific, PO
to Box 99, Swedesboro, New Jersey 08085) which grinds the polymer so that the
particles can fit through a mesh spacing of 2 millimeters. This ground powder
is
then placed in a spectrophotometer to measure color in a pure reflectance
mode.
Typical PET resins employed for photographic or x-ray films, packaging
applications, bottles, and the like have an L value of at least 65. Typical
PET
resins made using an antimony catalyst will have a and b values in the range
between -2 and +2. It is preferred to have L values close to 100 and to have a
and
b values close to zero.
ABSORBED LIGHT
PET has a strong absorbance band for light having a wavelength (~,) near
310nm. For many applications, such as x-ray and photographic films, it is
important that the PET absorb little, or no, light at wavelengths in the band
of 320
to 800nm due to presence of other materials (e.g., catalyst complexes) in the
PET.
There is no conventional technique for reporting the light absorbance property
of a
transparent polymer, although the underlying theory of measuring light
absorption
is well known in the art. Representative references discussing light
absorption, that
may be consulted in understanding the formula developed below, are Mechanism
a.~r d Theory in Orttanic Chemistr~r by T. H. Lowry and K. S. Richardson,
Harper &
Row Publishers (1976); Physical Chemistrx, by W. J. Moore, Prentice Hall
Publishers, 4~' ed. (1972); and Physical Methods in Chemistry, by R. S. Drago,
3o Saunders Publishers (1977).
Absorbed light values (ABS/L) recited herein are determined in accordance
with the following procedure, as illustrated in the Examples. A specific
sample
preparation method is used to measure and compare light absorbances from
several
PET samples differing by catalyst composition. A PET sample is first melt
pressed
3s into film typically 10 mils thick between two plates of metal. The film and
metal
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plates are quenched in cold water before the polymer can crystallize
substantially.
The measured crystallinity is less than 5 weight percent, typically 3 weight
percent.
The resulting films are visibly transparent. The film is removed from the
plates and
placed in a spectrophotometer for Light absorption measurement. Using a
spectrophotometer, the light absorption within the film is measured by
comparing
the intensity of light transmitted through the thin dimension of the film
relative to
the original light intensity incident normal to the plane of the film. The
absorbance,
A, at a wavelength, ~., is defined as
I
A (a.) = In I-~-
1o where Io is the incident light intensity and I is the intensity of light
which has
transmitted through the film and Ink is the logarithm with the base e, or
natural
Logarithm. .
According to the Beer-Lambert Law, the absorbance is proportional to the
polymer film thickness, L, and the concentration of any materials present in
the
film that may absorb light. Thus the quantity A(~,)/L indicates the amount of
absorbance per unit film thickness which is dependent only on the composition
within the film and independent of the film thickness.
Spectral data is provided with background correction so Io(~,) is unity.
Intensity is provided in terms of percent (%) of light transmitted through the
film.
2o Thus, absorbance per unit film thickness is determined in accordance with
the
formula:
yoo 1
1 I ~J~
L L
Since pure PET itself has strong absorbance band near the 310nm
wavelength, the films have practical use where transmission in longer
wavelengths
in the ultraviolet and visible spectrum; i.e., at wavelengths of 320 to 800nm.
One
useful means to measure and report the absorbance of light over the useful
range is
to integrate the absorbance per unit thickness throughout the spectrum of
useful
wavelengths. There is no standard way to report the film absorption over these
wavelengths, so the inventors choose an unweighted integration over the
3o wavelengths 320nm to 800nm. This property of the film, defined herein as
ABS/L,
is represented by the formula:
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800nmd~ In 1
1320 nm (I(~, ~
ABS /L =
L (800 - 320nm )
where the thickness is provided in mils; or thousandths of an inch. It is
noted that
this property is not a measurement of color or darkness. It is a total measure
of
how much light does not go through the material. However, when ABS/L is very
5 close to zero, then the material will be clear and uncolored. It is also
noted that
this property applies to regions of light which are invisible, roughly between
320 nm and 400 nrn. Light absorbance confined between 320 nm and 400 nm is
outside the common definition of visible light and would not be characterized
by
either the Hunter L, a and b color scale or any other description of visible
color or
1o visible transparency.
Typical commercial PET films used as the substrate for x-ray or
photographic films have an ABS/L value less than 15. It is preferred for films
to
have an ABS/L value close to zero. Antimony catalyst is the catalyst of choice
currently used to prepare those PET films. In practicing the invention, the
15 advantages of organic titanate catalysts may be realized, while achieving
color and
ABS/L performance comparable or superior to that obtained with antimony
catalyst.
PET PREPARATION
PET films and articles of this invention are made by the transesterification
20 or direct esterification process mentioned above, using conventional melt
or solid
state techniques, but using the catalyst system described below in lieu of, or
as a
partial replacement for, the conventional antimony or other prior art
polycondensation catalyst.
The catalyst system is soluble in ethylene glycol, has a high degree of
25 activity for polycondensation, and results in polymer having improved
optical
properties (e.g., less unwanted color, less absorbed light, and less scattered
light)
compared to polymer obtained using an organic titanate catalyst alone, or
organic
titanate catalyst systems disclosed in the prior art. The catalyst system is
prepared
by adding an organic titanate, a compound that will provide the ligands (such
as an
30 organic silicate and/or an organic zirconate), and preferably an organic
phosphoric
and/or phosphoric acid, to the selected alcohol. The alcohol that is selected
typically will be the glycol employed in preparing the polyester (i.e.,
ethylene
glycol for PET) for convenience in conducting the polymerization process. The
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WO 99/54379 PCT/US99/08339
polyester is produced in minimal temperature, to assist reducing thermal
degradation by-products, and in an atmosphere with minimal oxygen, to assist
in
reducing oxidative degradation by-products, and in contact with materials of
construction which minimally leach impurities into the reacting mixture. The
polymer can be of any molecular weight, but it is currently preferred that the
weight-average molecular weight be above 21,000, and most preferred above
44,000 Daltons. The polymer can also be prepared with comonomers which have
at least one alcohol group or at least one acid group or both groups. The
titanate
catalyst concentration can be about 0.01 to 500ppm, most preferrably 0.5 to
100ppm.
ORGArTIC TITANATE
Organic titanates that 'may be selected in practicing the invention have the
general formula:
Ti(OR)4
where R is a ligand group typically composed of carbon, oxygen, phosphorous,
silicon and/or hydrogen. Typically each R ligand group can contain at least
one
carbon, preferrably 3 or more. The presence of a halide, or of other active
substituent, in the ligand group generally is avoided since such groups may
interfere with catalytic reactions or form undesired by-products, which would
2o contaminate the polymer. While different ligand groups may be present on
the
same titanium atom, generally they can be identical to facilitate synthesis of
the
titanate. In some cases, 2 or more Rs may be from a common compound
chemically bonded together, other than at the titanium (i.e., a multidentate
ligand
and such as triethanolamine, citric acid, glycollic acid, malic acid succinic
acid,
ethanediamine). For a discussion of ligand denticity see for example F. Albert
Cotton and G. Wilkinson, Advanced Inoruanic Chemistry, 4th ed., Wiley-
Interscience, 1980.
Organic titanates are commonly prepared by mixing titanium tetrachloride
and the selected alcohol precursor in the presence of a base, such as ammonia,
to
3o form the tetraalkyl titanate. The alcohol typically is ethanol, n-propanol,
isopropanol, n-butanol, or isobutanol. Methanol generally is not selected
since the
resulting tetramethyl titanate is insoluble in the reaction mass, complicating
its
isolation.
Tetraalkyl titanates thereby produced are recovered by first removing by-
product ammonium chloride (e.g., by filtration), and then distilling the
tetraalkyl
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WO 99!54379 PCT/US99/08339
titanate from the reaction mass. This process generally is limited to the
production
of titanates having C4 or shorter alkyl groups since the higher temperatures
required to distill longer chain titanates (e.g., tetra-2-hexyl titanate)
cause some
degradation of the titanate. Titanates having longer alkyl groups are
conveniently
prepared by transesterification of those having alkyl groups up to C4 with
longer
chain alcohols. As a practical matter, the selected tetraalkyl titanate
generally will
have alkyl chains less than C12 since solubility of the titanate tends to
decrease,
and fabrication cost tends to increase, as the number of carbons increases.
Representative Commercial organic titanates that may be selected to
1o advantage include Tyzor~ TPT (tetra isopropyl titanate), TBT (tetra n-butyl
titanate), and TE (triethanolaminato isopropoxide titanate) available from
E. I. du Pont de Nemours and Company, Wilmington, Delaware, U.S.A.
ORGANIC PHOSPHORUS COMPOUNDS
Organic phosphoric and phosphiruc acids may be included in the organic
15 titanate-ligand catalyst solution to block titanium sites that otherwise
would be
attached by materials such as phosphorous that typically are present in
polymerization solution. If such materials are not present, however, there is
no
need to include these acids. Without being bound by theory, it appears that
the
conjugate base of the acid bonds to the organic titanate during preparation of
the
2o catalyst system.
The phosphoric and phosphinic acids have an alkyl or aryl group directly
bonded to the phosphorus atom. Typically the alkyl group will be a lower alkyl
group, having up to 3 carbon atoms, such as a methyl or ethyl group. If an
aryl
group is selected, it may be a phenyl or naphthyl ring. The alkyl and aryl
groups
25 may be substituted with substituent groups that do not unduly interfere
with
preparation of the catalyst system or subsequent reactions employing the
catalyst.
If phosphoric acid is selected, one of the two OH groups bonded to the
phosphorus atom may be esterified, if desired. Esters of phosphinic acid
generally
will not effectively bind to the titanate, so will not be selected.
3o The organic phosphoric acids tend to be stronger chelating agents than the
phosphinic acids, and may be selected for applications where a strong bond is
desired between the phosphorus compound and the organic titanate. Phenyl
phosphinic acid and diphenyl phosphinic acid have been found to provide an
excellent balance between reaction rate and preventing color generation in
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WO 99/54379 PCT/US99/08339
applications wherein the catalyst system is used as a polycondensation
catalyst for
the preparation of PET.
ORTHO SILICATES AND ZIRCONATES
The organic titanate-ligand catalyst system contains a cocatalyst radical or
ligand, typically added as an organic ortho silicate and/or zirconate, to
improve
color of polymer prepared with the catalyst system, and to promote solubility
of
the catalyst system in the glycol (i.e., to render the catalyst system glycol
soluble).
By "glycol-soluble" it is meant that essentially all of the titanium present
in the
catalyst system is dissolved in ethylene glycol, at room temperature, at
catalyst
to concentrations that are desired for the particular application. Typically
the
components are selected to form a catalyst system that is dissolved in
concentrations of at least 3 grams, preferably at least 5 grams, of catalyst
per
100 grams of glycol, to minimize the amount of glycol introduced to the
reaction
employing the catalyst system. Sufl'lcient glycol should be present, however,
to
~5 enable effective control over the catalyst addition rate for process
control
purposes.
The organic ortho silicates and zirconates that may be selected to
advantage have the structure Si(OR)4 and Zr(OR)4, respectively, and generally
are
prepared by introducing silicon tetrachloride or zirconium tetrachloride into
an
2o alcohol bath to replace the chlorides with alkyl groups from the alcohol,
in the
same manner as described above for preparing Ti(OR)4. The R is a ligand group
typically composed of carbon, oxygen, phosphorous, and/or hydrogen. The
presence of a halide, or of other active substituent, in the ligand group
generally is
avoided since such groups may interfere with catalytic reactions or form
undesired
25 by-products, which would contaminate the polymer. While different ligand
groups
may be present on the same titanium atom, generally they will be identical to
facilitate synthesis of the titanate. In some cases, 2 or more Rs may be from
a
common compound chemically bonded together, other than at the titanium (i.e.,
a
multidentate ligand and such as triethanolamine, citric acid, glycollic acid,
malic
3o acid, succinic acid, ethylenediamine).
If an organic silicate is selected, R is an alkyl chain having 1 to 8 carbon
atoms. Tetraethyl and tetra-n-propyl ortho silicates are representative
compounds
available from Silbond Company under the "Silbond" trademark. Tetraethyl ortho
silicate is a preferred ingredient.
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If an organic ortho zirconate is selected, R is an alkyl chain having 2 to
8 carbon atoms. Tetra n-propyl and tetra n-butyl ortho zirconate are
representative organic zirconates available from E. I. du Pont de Nemours and
Company under the "Tyzor" trademark. Choice of a particular ortho silicate or
zirconate will vary with the particular reaction to be promoted. An ortho
silicate is
preferred over an ortho zirconate, however, since it has less of an effect on
the
condensation rate.
CATALYST PREPARATION
The catalyst system can be prepared in ethylene glycol. While the
1o components may be added to the glycol in any order, it is preferred to
first add the
organic ortho silicate or zirconate, and then add the organic phosphinic or
phosphoric acid since the organic silicate or zirconate will aid the
phosphorus
compound to dissolve. Generally the mixture is stirred, and it may be mildly
heated (e.g., 40°C to 45°C) to completely solubilize the organic
phosphoric or
15 phosphinic acid. A minimum amount of the glycol is used (e.g., 10 to 20
moles per
mole of organic titanate that will be added later) to facilitate the
subsequent
reaction between the organic phosphoric or phosphinic acid and the organic
titanate. Presence of too much glycol serves no useful purpose, and
unnecessarily
increases the amount of glycol that is handled in the process.
2o The organic titanate then is added to the glycol solution containing the
phosphorus compound and organic ortho silicate and/or zirconate, conveniently
at
ambient temperature as the solution is stirred. This addition typically is
performed
under an inert atmosphere, such as nitrogen, since organic titanate
(e.g., tetraisopropyl titanate) reacts with the phosphorus compound,
liberating a
25 flammable alcohol (e.g., isopropanol). This reaction is exothermic, causing
the
glycol solution temperature to rise 10°C to 30°C (for the
particular components
noted above). Typically the organic titanate will be added, with stirring,
over a
period of 0.5 to 2 hours or more, then cooled to ambient temperature. The
catalyst system then is ready for use.
3o Alternatively, the phosphoric or phosphinic acid can be reacted with the
titanate to form a complex that can be isolated from the reaction by-product
alcohol by filtration. The isolated complex can then be added to a mixture of
the
ortho silicate or zirconate in ethylene glycol.
Relative quantities of the components will vary with the selected
35 compounds, but generally will be selected such that the molar ratio of P:Ti
in the
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WO 99/54379 PCT/US99/08339
catalyst system is within the range of 1:1 to 4:1. Higher amounts of the
phosphorus compound tend to cause an unacceptable decline in catalytic
activity,
while lower amounts tend to create an unacceptable level of polymer
discoloration.
The molar ratio of Si or Zr:Ti generally will be selected within the range of
1:1 to
4:1 since higher loadings of the silicate or zirconate tend to cause
unacceptable
loss of polymerization rate (with some color degradation), and lower loadings
generally do not provide the desired level of glycol solubility. The molar
ratio of
P:Si or Zr generally will be greater or equal to 0.5:1 since the lower ratios
typically
cause unacceptable levels of PET discoloration.
1o Structure of the catalyst system has not been established. Based on the
observed exotherm, however, it is believed that the components have reacted or
complexed in some manner to form binary or tertiary composition(s), at least
to
some extent, that render the catalyst system especially useful as a
polycondensation
catalyst in the manufacture of PET.
POLYMERIZATION REACTION
Antimony compounds currently are the catalyst of choice for the
polycondensation reaction that forms PET, by either the transesterification or
direct esterification route. In accordance with the invention, the catalyst
system
described above is substituted in whole or part for the antimony catalyst to
form
2o PET having desired optical properties (i.e., no or acceptable levels of
discoloration
and reduced light absorption). The catalyst system efficiently promotes the
polycondensation reaction at commercially required rates comparable to those
achieved with conventional antimony catalysts. Because it can be glycol-
soluble,
the catalyst can be readily distributed uniformly throughout the reaction
mass,
minimizing production control problems and producing PET having uniform
quality.
The catalysts are compatible with conventional esterification and
transesterification catalysts (e.g., manganese, cobalt, and/or zinc salts) and
may be
introduced to the production process concurrent with, or following,
introduction
so of the esterification catalyst. The novel catalysts also have been found to
be
effective in promoting the esterification reaction, and may be used as a
substitute
for some or all of the esterification catalyst as well as the polycondensation
catalyst.
13
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WO 99/54379 PCT/US99/08339
Quantities of the catalyst will vary with the selected process, but generally
will be in the range of 0.01 to 2000 ppm titanium based on the weight of
prepolymer in the polycondensation reaction mass. The preferred range selected
in
preparing PET is 10 to 200 ppm, typically 10 to 50 ppm. Other ingredients also
5 may be present to enhance catalyst stability or performance.
The catalyst system is particularly useful in preparing PET having a weight
average molecular weight of 21,000 or higher, typically employed in
applications
such as films, engineering and bottling resins, and fibers. Comonomers may be
present, to modify the properties of the resulting PET copolymer. For example,
comonomers can comprise diethylene glycol, dipropylene glycol, 1,3-propylene
glycol, 1,2-propylene glycol, glycolic acid, isophthalic acid, 2,6-naphthoic
acid,
lithium sulfonated isophthalic acid.
While the invention his been described in detail with respect to PET, it also
applies to other poly{alkylene arylates) where it is desired to use an
alternative to
~5 antimony as the polycondensation catalyst, while still obtaining excellent
optical
properties.
Having described the invention, it will now be illustrated, but not limited,
by the following examples.
EXAMPLES AND COUNTER EXAMPLES
2o All examples and counter examples were prepared identically except for the
identity of the catalyst systems being added. A master batch of oligo(ethylene
terephthate) had been previously prepared by esterifying terephthalic acid and
ethylene glycol without a catalyst to a number average degree of
polymerization of
16. Using a masterbatch of esterified oligomer helps to avoid loss of material
due
25 to sublimation during polycondensation and enhances reproducibility of
experimental results. All examples and counter examples were prepared from
quantities of this single master batch of this oligo(ethylene terephthalate).
For each
example and counter example a 1-liter resin kettle was provided with a Jiffy
Mixer
agitator rotating at 60 rpm, a thermocouple, condenser and nitrogen sweep. To
3o this kettle was added 400 grams of oligo(ethylene terephthalate), 115 ml of
ethylene glycol and then the catalyst system to be tested. The agitator was
turned
on and the temperature was increased to 275°C over a period of 45
minutes. The
contents were polymerized by holding under agitation at 275°C and a
pressure of
120 torn for 20 minutes, and at 280°C and a pressure of 30 ton for an
additional
35 20 minutes. The contents were then held under agitation at 280°C and
a pressure
14
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WO 99/54379 PCT/US99/08339
of 0.5 ton for a time sufficient to reach 15 oz-in (ounce-inches) torque as
measured by an Electro-Craft Motomactic torque controller. The time in minutes
for this step was recorded as the Finish Time and varied with the catalyst
used.
The polymer melt was then poured into a water bath to solidify the melt. A
s portion of the resultant solid was then annealed at 160°C for 16
hours and ground
to pass through a 2mm filter for color measurements as previously described. A
separate portion of the resultant solid was placed between to sheets of metal,
melt-
pressed to a thickness typically 7 mil (thousandths of an inch), quenched to
an
amorphous film for light absorption measurements as previously described.
to The following Table of Examples and Table of Counter Examples provide
an abbreviation for the catalyst system; the aforementioned Finish Time in
minutes;
the weight average molecular weight, Mw, as determined by size-exclusion
chromatography in hexafluoroisopropanol solvent; the reflective Hunter L_, a
and b_
polymer color measurements of the ground powder portion as described
is previously; and the light absorbance per unit film thickness ABS/L for the
film
portion as described previously. The catalyst components added to each resin
kettle were measured by weight in grams relative to the weight of
oligo(ethylene
terephthalate) masterbatch in grams expressed in parts per million, i.e., mg
of
catalyst entity per kg of oligomer. The Table of Examples and Table of Counter
2o Examples report the weight of catalyst component in ppm of active element
within
the catalyst compound, such as ppm of titanium for a titanate compound, ppm
silicon for a silicate compound, ppm zirconium for a zirconate compound or ppm
phosphorous for a phosphor acid. Abbreviations for each compound are
identified
under the table where the compound is used.
CA 02321705 2000-08-29
WO 99/54379 PCT/US99/08339
Table of Eaamnles
............. .............:::.:.:::.:-:.~.::::::.;--
. ::::..:::::::::-::::::.....::::::::.::-:
:::.:::::::::::::~:~::...:::....:::..:.._.:.....:-,.::::::::.::::::......
..................... . ,::.:.:......:::::...::-:.::.::i.
:.:~::.::::....:::::::~~:.......~:.:~::::..::::::::::-:::::>:::
.. .....................
:~._:::::::::~:J:~:.:...:.:;~:::.~t,::::..:?~:?.::-:x?:.::....:?>::::
............................... t :.........
................................,.....
. . u.~,.n.....:....................
.......... ............ . 'w' ....
:n................._
........................................:::: . .
.n..........
;:.:t:.::::::t.:::::::i:??::.: . - .
.........
..........................::.:.........................
....... ..: . .f .i:.v......
.:.: . . .. '~ . ..
.................. $ .............:::-
................,.....t. . ::::::::::
.......,.........:............ ... .. .. ....
:u::::::.
............ . ...i .:::ts...:
n.......... .. fv:x .:.:::::::::::::::.
....
......n.x. .. t,,~ :.:.
.. .. -.;:: :?..::
......v.............. . .
.. ... .. 'i .. .
.............Y s .
..........:..::.:: s ,.
::....n. , .. ~:::::
. . .... -..
..... ~. ..:. .....:..:.
..s..:.: rv ..... ......
:.:::::................. . ::.., .4.:.
... .s yt.
. -tt-s
r ). :::,.~$-t:.;.' ;
.............:.. : . -
... '- :. ::::-i ...s...
..........n..... .. .>:
.. .
r.... n:e:. : .
r.. r .
... . ....
. ..i...
................ f.G~.. ~r..'
::::\v: n:~. .....:4::~iii:::
~ .,'' '~> :.. :.'-
't ~t . . .~
Y:-::':.'. .. v?.:'v' -:
x::w::: ,:. a0
: .:..i.. .
:::::::::......... ...,c...:-.... . .:.. ...-......
.. . :
':fy :
:::::::::.-u'. t:t. -
n a f f
...n.r.::n.:::: f . :i
.. :'
r
:: ~:>t
.:: .
:.-. :..::~y~
tii:
...::::.r~h...t.:..........::...:..~f:' .
:..n.:.:::. : :
...:.< ~:..
::::::::....,.::::... ....
.i~..:a;ufc.n.. t nt-::
v?........x..... '.
i
. ?
., n~
..:.k:t.;u.-:-i::::
~
..'
-.-:-:va5c'::...
...,
.v:
.~
.i:
:
.....
s
:::::nv.-
G::~:
t.:.>.
'
r
.
f
x...::i.
'
....fi,~'..:
:
:
s.,fiv.ns.
i
.
.~!s....
:i
:n........
rcx
%-
~
_-
't
:
r:
a,;;:
:f
~
~>
:::f':
-
?
'::'::
. . .. .. . ... ..
. ~ .......... . :
. . . .... . n 7~/:.. . .
. . . ...n.... . ... ........-
. . .. ::n:t:n :..
. .". .. 1 ''.::
~::::~:::.f::.....f .. ...:::.:-.: : :j:
. .. :.. . . .::... :....~..
. s ..' ..o .........
,:: ... ~v ::e: .
....v...ss::..... . i :::2~'~ ~ ......
..: .n_s;:;;_:ivv: : 2h.....; ..............
... .. .. ........- . - ...a, .;. ..............
.. r : ::: :Qv: :
vy "...:.,..ti9v. ~ .. .
::r:i:.: . . ... ~: :
s~ : .... .. .. :.i ?
?w: x--i: .. ......n...::::.
. ..u:;:;.. ... :avs . ti'i.:~::i'v'~
. : n ~iiii::? ~ -... ....
. . .
=~ t.nn f
. ..... a-... . ..
. . ...n.n :fA:
....... . . .......
v .
s :
' '
.. . . . ?sv::w::::::.:::::: .
. .... ....:?.................... ..... . ......
:~.'::::::n::::::7lfw::!-... v -::::::::::::: ...
....................
.. . ..... ::~... ....
. . .-.::::::::::/-5. .
-::::::?::Y'.':~.'i-.:S :. t
:v:::nvn ::::t.: :.~::: ,s.n.....:.::..::nv::::-n:??:v.:......
ii:?-'.-i:i:v::: .... .............
::::::::: n
......, va...v....sv.............~._
s
......
1 2.6ppm Ti,Tyzor 100 34,40067.9 -0.5 6.0
TE 5.1
80ppm Zr,TPZr
lppm Si,TEOS
7ppm P,H3P04
2 l.3ppm Ti,Tyzor 175 27,80074.0 -0.7 6.1
TE 5.1
40ppm Zr,TPZr
20ppm Si,TEOS
7ppm P,H3P04
3 8ppmTi,Ti(PhP)4 150 25,60069.4 -1.9 3.9
' 9.2
4 8ppm Ti,Ti(PhP)4 120 25,30070.3 -1.7 4.3
8.6
40ppm Zr,Zr(PhP)4
5 8ppm Ti,Tyzor TE 340 21,10070.0 -1.1 5.0
5.0
40ppm Zr, Zr(Bu2PH0)
6 l2ppm Ti, TLF8954 145 24,60076.7 -1.3 5.3
6.4
7 l2ppm Ti,Tyzor TE 130 24,50077.5 -1.5 5.6
6.6
40ppm Zr, Zr(Bu2PH0)
Tyzor TE is titanium(I~ (triethanolaminato)isopropoxide supplied commericially
by E.I.
du Pont de Nemours, Inc.
TPZr is tetra-n-propyl zirconate
TEOS is tetraethyl orthosilicate
H3P04 is phosphoric acid
Ti(PhP)4 is titanium(I~ tetra-phenylphosphinate salt
l0 Zr(PhP)4 is zirconium(I~ tetra-phenylphosphinate salt
Zr(acac)4 is zirconium(I~ tetra(acetylacetonoate)
Zr(Bu2PH0) is zirconium tetra(dibutyl phosphinate)
TLF8954 is a mix of Ti(OC3H.~)3 [02P(OC4H9)2] + Ti(OC3H7)3 [02(HO)P(OC4H9)]
15
16
CA 02321705 2000-08-29
WO 99/54379 PCT/US99/08339
Table of Counter EaamDles
..'.,.:::::: . ::::. .
::.~ ....: ::.. :ivt.:::i:
. ,. .. ::>':.
..:. .:.. ... o:....,..-
::: .. ..... .:.
. ..i.:-0. ._ .
. C ... .
...: ...~1.:. . 1.
:....._._ . a
.: .:i:~~.,,.... ..
. ~::isGl:::4. ...
. i;:k;'Y ..
...::t:.::::..::::: . . .;
:.:..'t.:.:. . ':'v.\''6::'f:W.a::US;.
:.:::.:. r. ..'.S%'::,::,r'
, .1.... :.:?itv ~L:"
11. . i':'::' uF:';''i
_ .....5 ....f
'~$i.:nl.n;L, n,. i :.:..
xbnstkb .u~.~;~',~:,,.,.~..,....~.~~~,~~~~ '
:
.~ . ~:'~>.... -tn
~.,.i..,t::.:. f ..
:,..1::, ..
~. :.yli.:~:: r,:.i.,P;::.:.-.
4. .'
::. >,::."~.,;;n >
.f~~''.~ :'" ~'''~:'i,'-'.;:::
~'.o-., ', r$1
~j, Ml ~ryn...u
.:.n.~. a .
.. ' .:.t~
~~ .
.h,~. iir
.. ~s.n~iv
:::''0.:vxv .,;.;.5,:.
S
.vY:: .
. ...7...
:.'r..k7 it::::
. ...
.... .
...:~ :if
.. ::f\.y
v, :
~.. :
~SV::_..:;...h~ i7
'
.. a
:
.
~
~'
~'
'
5~:!r
. . .
:%i: ;:;x:~' ... . ::,:ky:;::.
., % :~.i. ~I
.. : .......1r -'.:'r',R'E:'-::'. ' ;
.... . . ~ I - : :;' :
.... . .. .... .. : :.,r::t: .
. . ... .. .. . : ;. ::::: r ~
: . ...... ......, f :. .. . ~:
... . ' .. ~ ~ ,.-v:
r ? ' ~
' . .~
:N :
: . , . ::::t...... _
..... . . . .:. :
... , i::.:::..: ..
. . .:: ..
:: .
.:
'
~
1 200ppm Sb,Sbz03 230 27,400 75.1-1.1 6.2 11.7
2 0.12%Ti(OBu)4 55 27,300 65.4-0.4 12.6 9.6
0.032%Zr(OPr)
4
3 8ppm Ti, Ti(OBu)4 140 25,800 67.1-0.9 9.6 8.4
4.2ppm Zr, Zr(OPr)4
4 8ppm Ti, Ti(OBu) 160 26 69.0-1 11 8
700 2 3 6
4 , . . .
4.2ppm Zr, Zr(OPr)
4
7ppm P,H3P04
8ppm Ti, Ti(TEA)4 125 27,200 72.9-0.8 9.4 6.1
6 8ppm Ti,Ti(OiPr)4 140 24,900 70.5-1.4 8.6 6.3
7 8ppm Ti,Ti(OiPr) 130 24 71.2-0 8 6
900 8 4 5
4 , . . .
8 8ppm Ti,Ti(OiPr)4 185 27,200 70.3-1.3 5.9 6.2
7ppm P,H3P04
9 8ppm Ti,Ti(OiPr) 220 24,800 71.7-1.0 6 6
2 4
4 . .
7ppm P,H3P04
98ppm Ti(OAc)4 80 27,600 61.6-0.7 9.8 8.5
1280 ppm ZlOCIz
11 98ppm Ti(OAc)4 135 27,600 64.10.1 14.0 8.1
472ppm Zi0(N03)z
12 8ppm Ti,Ti(OAc)4 165 25,300 69.7-0.8 10.9 6.8
40ppm Zr, Zi0(N03)z
7Pp~ Hs~a
13 8ppmTi, Ti(OAc)4 100 28,600 68.1-0.8 12.3 7.5
7PP~ Hs~a
14 50ppm Ti, TLF8954 135 24,500 75.2-1.4 5.5 6.3
8ppm Ti,Ti(PhP)4 110 25,700 71.6-1.4 6.4 6.5
40ppm Zr,Zr(PhP)4
7ppm P,H3P04
16 l.3ppm Ti,Tyzor 75 27,600 72.5-1.1 5.8 6.3
TE
lppm Si,TEOS
17 8ppm Ti,Tyzor 125 24,500 69.7-1.0 8.8 6.3
TE
40ppm Zr,Zr(acac)4
17
CA 02321705 2000-08-29
r
WO 99/54379 PCT/US99/08339
Sb203 is antimony trioxide
Ti(OBu)4 is titanium(I~ tetra(n butoxide)
Zr(OPr)4 is zirconium(I~ tetra(n-propooide)
H3P04 is phosphoric acid
5 TifTEA)4 is titanium(I~ tetrakis-triethanolamine
Ti(OiPr)4 is titanium(I~ tetra(isopropoxide)
Ti(OAc)4 is titanium(I~ tetra(acetate)
ZrOCIz is zirconyl dichloride
Zr0(N03)2 is zirconyl dinitrate
l0 Zr(acac)4 is zirconium(I~ tetrakis(acetylacetonoate)
Zr(EDTA) is zircoruum(I~ edetic acid salt
Zr(MBT) is zirconium(I~ mercaptobenzothiazole
Tyzor TE is titanium(I~ (triethanolaminato)isopropoxide supplied commericially
by E.I.
du Pont de Nemours, Inc.
15 TEOS is tetraethyl orthosilicate
Ti(PhP)4 is titanium(I~ tetra-phenylphosphinate salt
Zr(PhP)4 is zirconitun(I~ tetra-phenylphosphinate salt
Zr(acac)4 is zirconitun(I~ tetra(acetylacetonoate)
TLF8954 is a mix of Ti(OC3H7)3 [02P(OC4H9)2] + Ti(OC3H7)3 [02(HO)P(OC4H9)]
20
Examples 1 and 2 illustrate the use of titanates, silicates, zirconates and
oxy-phosphor compounds. The polymerization times are small to reach high
molecular weight, and the final materials have low color (low values of Hunter
a,
b_) and absorb very little light (high Hunter L value and low ABS/L). This
system
25 illustrates excellent results for preferred polymer quality. Examples 3 and
use a
single organic titanate-phosphinate ligand catalyst system and a combination
of
organic titanate-phosphinate and organic zirconate-phosphinate, respectively.
The
polymerizations reach high molecular weight quickly and the products transmit
light well, although the Hunter b color is high. Examples 5, 6 and 7 are
further
3o examples using other organic titanate, zirconate and oxy-phosphor
compounds.
Polymerization times are low to reach high molecular weight while the product
color is low and the total light absorption within the films is low.
Counter Example 1 illustrates the typical performance of antimony catalyst
at the concentrations typically used in commercial manufacturing. Although the
s5 Hunter b value is low, the Finish Time is long and the polymer films
absorbs too
much light (higher ABS/L).
18
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WO 99/54379 PCT/US99/08339
Counter Examples Z and 3 are counterexamples to the technology
described in Hoeschele's patent [US 5,120,822) and Schultheis [U.S.
3,326,965].
Compared to the examples of the invention, these materials are more yellow
(higher b values) and absorb more light (higher ABS/L). Thus this use of
titanates
s and zirconates is not as desirable as the examples. However, Hoeschele's
patent
specifically excludes consideration of titanates and zirconates for PET as the
ethylene glycol repeat unit has 'vicinal' alcohols. Counter Example 4
illustrates
that addition of phosphoric acid greatly extends the Finish Time without
improving
the Hunter b value or the film light absorbance. Findings from the use of
titanates
to and zirconates with PET polymerization are not anticipated by the patents
because
we have learned (a) when phosphoric acid is added to a polymerizing mixture
the
titanium alkoxide catalysts are no longer highly active, and (b) zirconium
alkoxides
form gels in the ethylene glycol. Catalyst and cocatalyst systems employed in
preparing polyethylene terephthalate) of the invention are soluble in ethylene
z5 glycol which permits convenient injection of the catalysts into the
polymerizing
rruxture.
Counter Examples 5,6 and 7 are counterexamples to the technology
described in Werber's patent [US 3,056,818]. Counter Examples 8 and 9
illustrate
this technology when phosphoric acid is added to the reaction mixture.
Compared
2o to the Examples, the polymerization times are longer as the catalyst is
more
deactivated when H3P04 is added to the polymerizing mixture. The final
materials
absorb more light (higher ABS/L). Thus this use of titanates is not as
desirable as
the examples. Research provides the unanticipated result that Weber's titanium
and/or zirconium catalysts are deactivated by even small amounts of metal
25 scavengers, e.g., phosphoric acid, present during the polymerization. In
addition
no results including Ti+Zr are mentioned, nor is there mention of any
advantage
from the combination. Werber's claims include compounds which produce color
and/or have only minute solubility in ethylene glycol. The Examples also
quantify
the surprising high reaction rate with the color and light transmission
advantages
3o from using oxy-phosphor containing ligands on the titanate and/or
zirconate.
Counter Example runs 10 and 11 are counterexamples to the technology
described in Hasegawa's patent [JP 46-27,552]. Counter Examples 12 and 13
illustrate the effect of adding phosphoric acid to the reaction mixture.
Compared
to the Examples, the final materials are much more yellowed (higher Hunter b_
35 values) and absorb more light (higher ABS/L). Thus this use of titanates
and
zirconates is not as desirable as the examples. Hasegawa's findings do not
mention
color or light absorbance properties of the final material, only heat
resistance. The
19
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WO 99/54379 PCT/US99/08339
titanate is restricted to a fatty acid salt of titanium and only titanium
acetate is
disclosed. Further, all zirconium compounds are restricted to zirconyls. The
only
Zr+P compound mentioned is zirconyl metaphosphate which is insoluble in
ethylene glycol. The counterexamples show that the zirconyls have a
detrimental
5 effect on the final material's color and light absorbance properties.
Counter Example run 14 contains the same organic titanium-ligand catalyst
system as Example run 6, except at more than four times the titanium
concentration. The polymerization times, product molecular weights and colors
are
comparable, however the Counter Example run 14 absorbs much more light. Thus
1o it is not useful in some critical applications.
Counter Example run 15 contains the same catalyst system as Example run
4 in the same relative concentrations with the addition of phosphoric acid.
The
polymerization times, product molecular weights and Hunter L, _a colors are
comparable. Although the Counter Example run 15 is much less yellow, it
absorbs
15 more light. The addition of phosphoric acid is known in the art to reduce
color, but
this comes at the price of increased light absorbance overall. Hence this
Counter
Example is not useful in some critical applications.
Counter Example runs 16 and 17 utilize the same organic titanate-ligand
catalyst as in Example runs 1, 2, 5 and 7, except with different cocatalyst
systems.
2o In both cases high molecular weight is attained in small reaction times, so
these are
effective catalysts. The former run's product is substantially less colored,
but both
runs produce polymer which absorbs substantial amounts of light (high ABS/L).
Therefore these products are not useful in some critical applications.
ADDTl'IONAL EXAMPLES
25 Example 8 Preparation of Polypropylene tereohthalatel
Oligo(propylene terephthalate) is prepared by esterifying terephthalic acid
and 1,3-
propylene glycol without a catalyst to a number average degree of
polymerization
of about 16. A 1-liter resin kettle is provided with a Jiffy Mixer agitator
rotating at
60 rpm, a thermocouple, condenser and nitrogen sweep. To this kettle is added
30 400 grams of oligo(propylene terephthalate), 115 ml of propylene glycol and
then
an organic titanate-ligand catalyst system. The agitator is turned on and the
temperature is increased to 255°C over a period of 45 minutes. The
contents are
polymerized by holding under agitation at 255°C and a pressure of 120
ton for
20 minutes, and at 255°C and a pressure of 30 ton for an additional 20
minutes.
35 The contents are then held under agitation at 255°C and a pressure
of 0.5 ton for a
time sufficient to reach 15 oz-in (ounce-inches) torque as measured by an
Electro-
20
CA 02321705 2000-08-29
WO 99!54379 PCT/US99108339
Craft Motomactic torque controller. The time in minutes for this step is
recorded
as the Finish Time and varies with the catalyst used. The polymer melt is then
poured into a water bath to solidify the melt. A portion of the resultant
solid is
annealed at 160°C for 16 hours and ground to pass through a 2mm filter
for color
measurements as previously described. A separate portion of the resultant
solid is
placed between to sheets of metal, melt-pressed to a thickness typically 7 mil
(thousandths of an inch), quenched to an amorphous film for light absorption
measurements as previously described. The weight average molecular weight is
greater than 21,000 and the ABS/L is less than 6.1.
1o Example 9 Preparation of Poly(but~rlene ter~hthalatel
Oligo(butylene terephthalate) is prepared by esterifying terephthalic acid and
butylene glycol without a catalyst to a number average degree of
polymerization of
about 16. A 1-liter resin kettle is provided with a Jiffy Mixer agitator
rotating at
60 rpm, a thermocouple, condenser and nitrogen sweep. To this kettle is added
15 400 grams of oligo(butylene terephthalate), 115 ml of butylene glycol and
then an
organic titanate-ligand catalyst system. The agitator is turned on and the
temperature is increased to 275°C over a period of 45 minutes. The
contents are
polymerized by holding under agitation at 275°C and a pressure of 120
ton for
20 minutes, and at 275°C and a pressure of 30 torr for an additional 20
minutes.
2o The contents are then held under agitation at 275°C and a pressure
of 0.5 ton for a
time sufficient to reach 15 oz-in (ounce-inches) torque as measured by an
Electro-
Craft Motomactic torque controller. The time in minutes for this step is
recorded
as the Finish Time and varies with the catalyst used. The polymer melt is then
poured into a water bath to solidify the melt. A portion of the resultant
solid is
25 annealed at 160°C for 16 hours and ground to pass through a 2mm
filter for color
measurements as previously described. A separate portion of the resultant
solid is
placed between to sheets of metal, melt-pressed to a thickness typically 7 mil
(thousandths of an inch), quenched to an amorphous film for light absorption
measurements as previously described. The weight average molecular weight is
3o greater than 21,000 and the ABS/L is less than 6.1.
Example 10 Preparation of Pol~prop3rlene naphthalatel
Oligo(propylene naphthalate) is prepared by esterifying 2,6-naphthoic acid and
1,3-
propylene glycol without a catalyst to a number average degree of
polymerization
of about 16. A 1-liter resin kettle is provided with a Jiffy Mixer agitator
rotating at
35 60 rpm, a thermocouple, condenser and nitrogen sweep. To this kettle is
added
21
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400 grams of oligo(propylene naphthalate), 115 ml of propylene glycol and then
an
organic titanate-Iigand catalyst system. The agitator is turned on and the
temperature is increased to 255°C over a period of 45 minutes. The
contents are
polymerized by holding under agitation at 255°C and a pressure of 120
ton for
5 20 minutes, and at 255°C and a pressure of 30 ton for an additional
20 minutes.
The contents are then held under agitation at 255°C and a pressure of
0.5 ton for a
time sufficient to reach 15 oz-in (ounce-inches) torque as measured by an
Electro-
Craft Motomactic torque controller. The time in minutes for this step is
recorded
as the Finish Time and varies with the catalyst used. The polymer melt is then
1o poured into a water bath to solidify the melt. A portion of the resultant
solid is
annealed at 160°C for 16 hours and ground to pass through a 2mm filter
for color
measurements as previously described. A separate portion of the resultant
solid is
placed between to sheets of metal, melt-pressed to a thickness typically 7 mil
(thousandths of an inch), quenched to an amorphous film for light absorption
15 measurements as previously described. The weight average molecular weight
is
greater than 21,000 and the ABS/L is less than 6.1.
Example 11 Prgparation of Polyethylene nanhthalate)
Oligo(ethylene naphthalate) is prepared by esterifying 2,6-naphthoic acid and
ethylene glycol without a catalyst to a number average degree of
polymerization of
2o about 16. A 1-liter resin kettle is provided with a Jiffy Mixer agitator
rotating at
60 rpm, a thermocouple, condenser and nitrogen sweep. To this kettle is added
400 grams of oligo(ethylene naphthalate), 1 I5 ml of ethylene glycol and then
an
organic titanate-ligand catalyst system. The agitator is turned on and the
temperature is increased to 275°C over a period of 45 minutes. The
contents are
25 polymerized by holding under agitation at 275°C and a pressure of
120 ton for
20 minutes, and at 275°C and a pressure of 30 ton for an additional 20
minutes.
The contents are then held under agitation at 275°C and a pressure of
0.5 ton for a
time sufficient to reach 15 oz-in (ounce-inches) torque as measured by an
Electro-
Craft Motomactic torque controller. The time in minutes for this step is
recorded
3o as the Finish Time and varies with the catalyst used. The polymer melt is
then
poured into a water bath to solidify the melt. A portion of the resultant
solid is
annealed at 160°C for 16 hours and ground to pass through a 2mm filter
for color
measurements as previously described. A separate portion of the resultant
solid is
placed between to sheets of metal, melt-pressed to a thickness typically 7 mil
35 (thousandths of an inch), quenched to an amorphous film for light
absorption
measurements as previously described. The weight average molecular weight is
greater than 21,000 and the ABS/L is less than 6.1.
22
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Examvle 12 Pre»aration of Polv(eth 1 ne i ophthalatel
Oligo(ethylene isophthalate) is prepared by esterifying isophthalic acid and
ethylene
glycol without a catalyst to a number average degree of polymerization of
about
16. A 1-liter resin kettle is provided with a Jiffy Mixer agitator rotating at
60 rpm,
a thermocouple, condenser and nitrogen sweep. To this kettle is added 400
grams
of oligo(ethylene isophthalate), 115 ml of ethylene glycol and then an organic
titanate-ligand catalyst system. The agitator is turned on and the temperature
is
increased to 275°C over a period of 45 minutes. The contents are
polymerized by
holding under agitation at 275°C and a pressure of 120 ton for 20
minutes, and at
0 275°C and a pressure of 30 ton for an additional 20 minutes. The
contents are
then held under agitation at 275°C and a pressure of 0.5 torr for a
time sufficient to
reach 15 oz-in (ounce-inches) torque as measured by an Electro-Craft
Motomactic
torque controller. The time irl minutes for this step is recorded as the
Finish Time
and varies with the catalyst used. The polymer melt is then poured into a
water
bath to solidify the melt. A portion of the resultant solid is annealed at
160°C for
16 hours and ground to pass through a 2mm filter for color measurements as
previously described. A separate portion of the resultant solid is placed
between to
sheets of metal, melt-pressed to a thickness typically 7 mil (thousandths of
an
inch), quenched to an amorphous film for light absorption measurements as
2o previously described. The weight average molecular weight is greater than
21,000
and the ABS/L, is less than 6.1.
Example 13 Preparation of Poly(nropylene isonhthalatel
Oligo(propylene isophthalate) is prepared by esterifying isophthalic acid and
1,3-
propylene glycol without a catalyst to a number average degree of
polymerization
of about 16. A 1-liter resin kettle is provided with a Jiffy Mixer agitator
rotating at
60 rpm, a thermocouple, condenser and nitrogen sweep. To this kettle is added
400 grams of oligo(propylene isophthalate), 115 ml of propylene glycol and
then
an organic titanate-ligand catalyst system. The agitator is turned on and the
temperature is increased to 275°C over a period of 45 minutes. The
contents are
3o polymerized by holding under agitation at 275°C and a pressure of
120 ton for
20 minutes, and at 275°C and a pressure of 30 ton for an additional 20
minutes.
The contents are then held under agitation at 275°C and a pressure of
0.5 ton for a
time sufficient to reach 15 oz-in (ounce-inches) torque as measured by an
Electro-
Craft Motomactic torque controller. The time in minutes for this step is
recorded
3s as the Finish Time and varies with the catalyst used. The polymer melt is
then
poured into a water bath to solidify the melt. A portion of the resultant
solid is
23
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WO 99/54379 PCTNS99/08339
annealed at 160°C for 16 hours and ground to pass through a 2mm filter
for color
measurements as previously described. A separate portion of the resultant
solid is
placed between to sheets of metal, melt-pressed to a thickness typically 7 mil
(thousandths of an inch), quenched to an amorphous film for light absorption
measurements as previously described. The weight average molecular weight is
greater than 21,000 and the ABS/L is less than 6.1.
Example 14 Preparation of Polyethylene-co-propvlene terephthalatel
Oligo(ethylene terephthalate) is prepared by esterifying terephthalic acid and
ethylene glycol without a catalyst to a number average degree of
polymerization of
to about 16. A 1-liter resin kettle is provided with a Jiffy Iv~xer agitator
rotating at
60 rpm, a thermocouple, condenser and nitrogen sweep. To this kettle is added
400 grams of oligo(ethylene terephthalate), 115 ml of propylene glycol and
then an
organic titanate-ligand catalyst system. The agitator is turned on and the
temperature is increased to 255°C over a period of 45 minutes. The
contents are
15 polymerized by holding under agitation at 255°C and a pressure of
120 torr for
20 minutes, and at 255°C and a pressure of 30 torr for an additional 20
minutes.
The contents are then held under agitation at 255°C and a pressure of
0.5 ton for a
time sufficient to reach 15 oz-in (ounce-inches) torque as measured by an
Electro-
Craft Motomactic torque controller. The time in minutes for this step is
recorded
2o as the Finish Time and varies with the catalyst used. The polymer melt is
then
poured into a water bath to solidify the melt. A portion of the resultant
solid is
annealed at 160°C for 16 hours and ground to pass through a 2mm filter
for color
measurements as previously described. A separate portion of the resultant
solid is
placed between to sheets of metal, melt-pressed to a thickness typically 7 mil
25 (thousandths of an inch), quenched to an amorphous film for light
absorption
measurements as previously described. The weight average molecular weight is
greater than 21,000 and the ABS/L is less than 6.1.
Example 15 Preparation of Polyethylene-co-propylene naphthalatel
Oligo(ethylene naphthalate) is prepared by esterifying naphthalic acid and
ethylene
3o glycol without a catalyst to a number average degree of polymerization of
about
16. A 1-liter resin kettle is provided with a Jiffy Mixer agitator rotating at
60 rpm,
a thermocouple, condenser and nitrogen sweep. To this kettle is added 400
grams
of oligo(ethylene naphthalate), 115 ml of propylene glycol and then an organic
titanate-ligand catalyst system. The agitator is turned on and the temperature
is
35 increased to 255°C over a period of 45 minutes. The contents are
polymerized by
24
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WO 99/54379 PCT/US99/08339
holding under agitation at 255°C and a pressure of 120 ton for 20
minutes, and at
255°C and a pressure of 30 ton for an additional 20 minutes. The
contents are
then held under agitation at 255°C and a pressure of 0.5 ton for a time
sufficient to
reach 15 oz-in (ounce-inches) torque as measured by an Electro-Craft
Motomactic
torque controller. The time in minutes for this step is recorded as the Finish
Time
and varies with the catalyst used. The polymer melt is then poured into a
water
bath to solidify the melt. A portion of the resultant solid is annealed at
160°C for
16 hours and ground to pass through a 2mm filter for color measurements as
previously described. A separate portion of the resultant solid is placed
between to
to sheets of metal, melt-pressed to a thickness typically 7 mil (thousandths
of an
inch), quenched to an amorphous film for light absorption measurements as
previously described. The weight average molecular weight is greater than
21,000
and the ABS/L is less than 6.1.
25
