Note: Descriptions are shown in the official language in which they were submitted.
CA 02569001 2006-11-29
s
POLYESTER RESIN COMPOSITION, PROCESS FOR PRODUCING THE SAME, AND
POLYESTER FILM
Technical Field of the Invention
[0001] The present invention relates to a polyester resin composition, a
process for
producing the same, and a polyester film, and more specifically, to a
polyester resin
composition in which the content of cyclic compound (oligomer) is little and
the color tone is
good and which has a viscosity for extrusion in a general-purpose manner, and
a process for
producing the same, and a polyester film.
Background Art of the Invention
[0002] Generally, a polyester is a linear polymer synthesized from a
dicarboxylic acid or an
ester-forming derivative thereof and a diol or an ester-forming derivative
thereof. However,
as described in, for example, Non-Patent document 1, a cyclic compound is
generated in a
linear polymer based on the equilibrium. It is known that the cyclic compound
is a low-
molecular substance, it is precipitated in a polyester forming process, or
precipitated on a
surface of a product freely in time, in particular, it is much extracted in a
forming process or a
processing process or in a case where a solvent is used at the time of using a
product, and it
causes various troubles.
[0003] For example, in a case of a base film for magnetic recording media,
large protrusions
are formed by the precipitation of cyclic compound and the magnetic recording
may be
damaged, or in a case of an optical base film, the cyclic compound is
precipitated by heating
in a processing process and it may generate an optical turbidity or a
calescence point, or in a
case of a film laminated with a steel plate, a bloom may be generated in the
appearance after
lamination to the steel plate.
[0004] These cyclic compounds have been informed variously, and for example,
as to
polyethylene terephthalate, it is informed in, for example, Non-Patent
document 2, that the
main component of the cyclic compound is a cyclic trimer and it is generated
by an
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equilibrium reaction at the time of condensation polymerization of
polyethylene
terephthalate.
[0005] For the above-described problem, for example, in Patent documents 1 to
10, a
method for a solid phase polymerization of a polyester resin at a temperature
of not higher
than the melting pvint at a reduced-pressure condition in an inert gas
atmosphere is proposed.
[0006] However, in such a technology wherein the cyclic compound is reduced by
the solid
phase polymerization, although the amount of the cyclic compound is certainly
reduced,
because at the same time the condensation polymerization of the polyester
progresses and the
rise of the polymerization degree becomes great, the prepared material is not
suitable as a raw
material for producing a formed product little in content of cyclic compound.
[0007] Namely, if the polymerization degree of polyester becomes great, at the
time of
forming, the viscosity of the molten polymer becomes high, and therefore, the
load at the time
of extrusion becomes large or the polymer temperature rises by exothermic
ascribed to shear,
and a problem such as thermal decomposition occurs.
[0008] In order to solve such a problem, proposed are a method for adjusting
the pressure
reduction degree at the time of solid phase polymerization (Patent document
11), a method for
adjusting the flow rate of inert gas (Patent document 12), a method for
heating by an inert gas
atmosphere containing a glycol component (Patent document 13) and further a
method for
heating under a condition of an inert gas atmosphere after removing fine or
film-like
substances (Patent document 14). Even in these methods, however, because the
polymerization degree of the polyester obtained varies, it has been very
difficult to obtain a
polyester with a constant quality industrially.
[0009] Further, although Patent document 15 describes a technology for
reducing a cyclic
compound by heat treatment in an inert gas atmosphere, even in this method,
the amount of a
cyclic trimer can be certainly reduced, but there is a problem that the
polymer is colored.
Non-Patent document 1: "Polymer Chemistry" written by P. J. Flory, (translated
by Oka and
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CA 02569001 2006-11-29
Kanemaru, published by Maruzen Publisher Corporation) p90-97
Non-Patent document 2: "Saturated Polyester Resin Hand Book" written by Kazuo
Yuki,
(Nikkan Kogyo Newspaper Corporation) p 167-178
Patent document 1: Japanese Patent 3418987
Patent document 2: JP-A-2003-306538
Patent document 3: JP-A-2001-172372
Patent document 4: JP-A-11-199660
Patent document 5: JP-A-9-249744
Patent document 6: JP-A-9-59362
Patent document 7: JP-A-6-234834
Patent document 8: JP-B-51-48505
Patent document 9: JP-A-49-101462
Patent document 10: JP-A-53-101092
Patent document 11: JP-A-55-89331
Patent document 12: JP-A-55-89330
Patent document 13: JP-A-8-120062
Patent document 14: JP-A-2002-173528
Patent document 15: Japanese Patent 2745676
Disclosure of the Invention
Problems to be solved by the Invention
[0010] An object of the present invention is to solve the above-described
conventional
problems and to provide a polyester resin composition in which the content of
cyclic
compound is little, which is excellent in color tone and causes no significant
viscosity
lowering and viscosity rise, and can withstand a process which is exposed to a
long-term
thermal history, and which is suitable for forming by extrusion, a process for
producing the
same, and a polyester film.
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Means for solving the Problems
[0011] The above-described object of the present invention can be achieved by
the
following means.
A polyester resin composition having an equivalent spherical diameter of 1 mm
to 50
mm, a degree of crystallization of not less than 65% and less than 99%, an
intrinsic viscosity
of not more than 0.7 dl/g and a content of a cyclic trimer of not more than
0.4% by weight. A
process for producing a polyester resin composition wherein, when a polyester
resin
composition containing an antioxidant is heat treated, a temperature for the
heat treatment is
controlled at a temperature in a range of a melting point of the polyester
resin composition to a
temperature lower than the melting point by 80 C, and an atmosphere for the
heat treatment is
controlled so that a degree of flow of an inert gas becomes not more than 1
liter/hr per 1 kg of
the polyester resin composition.
[0012] A polyester resin composition wherein a content of a cyclic trimer is
in a range of 0.1
to 0.7% by weight, a content of a carboxylic end group is in a range of 15 to
40 equivalent/ton,
an intrinsic viscosity is in a range of 0.55 to 0.80, and an absorbance at a
wavelength of 365
nm of a solution prepared using orthochlorophenol as a solvent (0.8 g/lOml) is
in a range of
0.22 to 0.36.
Effect according to the Invention
[0013] According to the present invention, the amount of cyclic trimer can be
greatly
reduced, and a polyester resin composition the color tone of which is good,
which is little in
foreign materials and the viscosity of which is suitable for forming by
extrusion can be
provided. Further, according to the present invention, with a good color tone
and
substantially without changing an intrinsic viscosity of a raw polymer, only
the cyclic
compound can be reduced with a good productivity at a low cost. Furthermore,
by heat
treatment from a low-viscosity condition, while the intrinsic viscosity is
maintained at a usual
level, a polymer reduced in cyclic compound can be obtained.
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CA 02569001 2006-11-29
[0014] The polyester resin composition according to the present invention can
be spun,
formed into a film and molded without particularly changing usually employed
conditions,
and further, it becomes possible to prevent contamination of oil at the time
of spinning or
contamination of casting and stretching machines at the time of film formation
ascribed to
cyclic trimer. Further, a defect ascribed to precipitation of cyclic compound
can be
prevented at the time of using a product, and the product such as a film,
fibers or a bottle can
be used effectively. In particular, it is effective for use of magnetic tapes
or optical films,
and as a container for food and films for lamination with a steel plate, for
wrapping and for
electrical insulation.
The Best mode for carrying out the Invention
[0015] The polyester resin composition according to the present invention
includes first and
second polyester resin compositions described later. As the first and second
polyester resin
compositions described later in the present invention, polyethylene
terephthalate,
polyethylene isophthalate, polybutylene terephthalate, polypropylene
terephthalate,
polycyclohexanedimethylene terephthalate, polyethylene naphthalate, etc. can
be
exemplified, and further, it may be a copolymer thereof. Among these
polyesters,
polyethylene terephthalate and polyethylene naphthalate are preferred because
of good
properties as a film, and in particular, polyethylene terephthalate is most
preferable.
Although polyethylene terephthalate may be copolymerized, it is preferred that
not less than
90 mol% of polyester forming unit is a unit of ethylene terephthalate. In a
case where the
ethylene terephthalate unit is less than 90 mol%, the crystallinity of the
polyester deteriorates,
and there is a case where it becomes difficult to satisfy the degree of
crystallization in the
process for producing the polyester resin composition according to the present
invention.
[0016] As the component copolymerized with these polyesters, a dicarboxylic
component, a
glycol component and a polyfunctional component can be raised, and for
example, as the
dicarboxylic component, terephthalic acid, 2,6-naphthalene dicarboxylic acid,
diphenyl
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dicarboxylic acid, phthalic acid, isophthalic acid, sodium sulfoisophthalate,
and aromatic
dicarboxylic component thereof such as alkylester, adipic acid, sebacic acid
and aliphatic
dicarboxylic component thereof such as alkylester, 1,4-cyclohexane
dicarboxylic acid and
aliphatic dicarboxylic component thereof such as alkylester,can be
exemplified. As the
glycol component, ethylene glycol, diethylene glycol, propylene glycol,
butanediol, 1,4-
cyclohexane dimethanol, neopentyl glycol, spiro glycol, ethylene oxide adduct
of bisphenol
A, isosolvate, etc. can be exemplified. Further, as the polyfunctional
component,
polyfunctional carboxylic acid such as trimellitic acid or pyromellitic acid,
and
polyfunctional alcohol such as trimethylol propane or pentaerithritol, can be
exemplified.
Furthermore, hydroxy carboxylic acid such as p-hydroxy benzoic acid may be
used as the
copolymerized component.
[0017] In the first polyester composition according to the present invention,
after finishing
to polymerize polyester, it is appropriately cut by a method such as sheet
cutting or strand
cutting, and it is formed a particle-like (chip-like) shape. The shape of the
particles (chips)
may be arbitrary, but if it is too small and it becomes fine powder-like, it
may cause troubles
at a heat treatment process or a forming process thereafter. Further, in a
case where the
shape is large, although it does not particularly cause a problem with respect
to the meaning
for reducing cyclic compounds, there are problems from the viewpoint of
operation.
Therefore, the size of polyester composition (particle, chip) is preferably in
a range of 1 mm
to 50 mm in equivalent spherical diameter, and more preferably in a range of 2
mm to 20 mm.
Where, the equivalent spherical diameter means a diameter of sphere having the
same volume
as that of the polyester composition (particle, chip).
[0018] The degree of crystallization of the first polyester composition
according to the
present invention is preferably not less than 65% and less than 99%, more
preferably not less
than 70% and less than 95%, and most preferably not less than 75% and less
than 90%. In
the polyester composition having a degree of crystallization in such a range
and having such a
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CA 02569001 2006-11-29
shape, the amount of cyclic trimer is remarkably reduced. If less than 65%,
the amount of
cyclic trimer is hardly reduced similarly to in a usual polyester, and if 99%
or more, the
productivity is bad. The content of cyclic trimer in the first polyester
composition according
to the present invention is preferably not more than 0.4% by weight, more
preferably not more
than 0.3% by weight, and most preferably not more than 0.25% by weight. By
such a
condition where the amount of cyclic trimer is small, it becomes possible to
lengthen the time
for forming the polymer until the cyclic trimer is precipitated.
[0019] The intrinsic viscosity of the first polyester composition according to
the present
invention is preferably not more than 0.7 dl/g. If more than 0.7 dl/g, because
the viscosity is
high, improper extrusion or deterioration of polymer due to exothermic may
occur at the time
of forming, and nonuniform polymer may be produced. Further, it is necessary
to set a resin
temperature for forming at a high temperature in order to improve the property
for the melt
forming, and as the result thereof, a cyclic compound is liable to be
generated in a product.
Further, as the lower limit, not less than 0.4 dl/g is preferable. In a case
where the intrinsic
viscosity is lower than 0.4 dl/g, a problem on forming such as yarn cut at the
time of spinning,
film breakage at the time of film formation or breakage at the time of forming
is likely to
occur, and therefore, in particular, the composition having an intrinsic
viscosity of not less
than 0.4 dl/g and not more than 0.7 dl/g is preferably used.
[0020] In a case where the first polyester composition according to the
present invention is
used, for example, as a raw material for forming a film, when a content of
alkali metal element
is referred to as Ma (mol/t), a content of alkaline earth metal element is
referred to as Md
(mol/t) and a content of phosphorus element is referred to as Mp (mol/t), it
is preferred that
Ma, Md and Mp satisfy the following equation.
Ma+2xMd ? 3xMp
[0021] The above-described equation has the same meaning as "M - P? 0" if "Ma
+ 2 x
Md" is referred to as M and "3 x Mp" is referred to as P, and preferably, M -
P 0.5 is
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CA 02569001 2006-11-29
satisfied. If M - P<0, the property of electrostatic casting becomes bad, air
is likely to be
involved between a film and a casting drum at the time of melt extruding and
casting, a state
in which the speed for film formation must be lowered is liable to occur, and
reduction of the
productivity may be caused. Further, although the reason is not clear, by
controlling the
amount of elements of the polyester composition in the above-described range,
it becomes
possible to accelerate the suppression of precipitation of cyclic trimer to
the surface and
further to decrease the amount of cyclic trimer faster at the time of heat
treatment. Although
the compound containing alkali metal element and the compound containing
alkaline earth
metal element for satisfying the above-described equation are not particularly
limited,
concretely, for example, lithium acetate, sodium acetate, potassium acetate,
magnesium
acetate, potassium hydroxide, sodium hydroxide, magnesium hydroxide, etc. can
be used.
[0022] In the first polyester composition according to the present invention,
it is preferred
that the number density of particles having a maximum diameter of not less
than 1 m and
containing an element of Ti, Sb or Ge is less than 10,000 per 1 mg of the
polyester
composition. More preferably, it is less than 5,000. If this number density is
not less than
10,000, when converted into a polyester film, the surface roughness may be
enlarged, or the
transparency of the film may be damaged.
[0023] The first polyester composition according to the present invention
preferably
contains a trivalent phosphorus compound, and the content thereof is
preferably in a range of
1 to 100 ppm relative to the polyester composition as a weight of phosphorus
atoms. More
preferably, it is in a range of 5 to 50 ppm. If the content is more than 100
ppm, the
polymerization reaction property tends to be deteriorated, and if the content
is less than 1
ppm, it becomes difficult to maintain the thermal resistance. Where, the
content means the
amount with respect to phosphorus atoms of trivalent phosphorus compound, and
by
employing the trivalent phosphorus compound, the thermal resistance is
maintained as well
as, although the reason is not clear, the reduction speed of cyclic trimer is
decreased.
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[0024] In the first polyester composition according to the present invention,
it is preferred
that titanium element is contained in a range of 0.5 to 50 ppm as a weight of
titanium atoms
relative to the polyester composition obtained, because the polymerization
activity becomes
high and the color tone and thermal resistance of the obtained polymer become
good. If the
content is more than 50 ppm, the thermal resistance deteriorates, and further,
it is likely to
become a factor of foreign material ascribed to catalyst. More preferably, the
content is in a
range of 1 to 20 ppm. In order to contain a predetermined amount of titanium
element in the
polymer, a predetermined amount of a compound containing the element may be
added at the
time of addition thereof (the added amount is held in the polymer as it is).
Further, it is
preferred that the content of the alkali metal element is in a range of 1 to
30 ppm as a weight
of alkali metal atoms relative to the polyester composition, and by this, pH
in the system at the
time of polymerization can be raised, and the hydrolysis of the titanium
compound can be
suppressed. The content of alkali metal element is preferably in a range of 1
to 15 ppm. If
the content is less than 1 ppm, the effect for suppressing the hydrolysis is
poor, and if the
content is more than 30 ppm, it may cause generation of foreign materials. The
introduction
of alkali metal element can be realized, for example, by adding a compound
such as sodium
hydroxide, potassium hydroxide, sodium acetate or potassium acetate at a
predetermined
amount.
[0025] As the above-described compound containing titanium element, a titanium
chelate
compound or tetraalkoxy titanium compound is preferred. For example, titanium
chelates
such as titanium acetylacetonate, titanium tetraacetylacetonate, titanium
octyleneglycolate,
titanium lactate, titanium ethylacetoacetate, titanium citrate, titanium
peroxocitrate and
titanium ammonium, or alkyltitanate such as tetraisopropyltitanate,
tetrabutyltitanate, tetra(2-
ethylhexyl)titanate and tetramethyltitanate can be exemplified, and among
these, titanium
chelate or tetrabutyltitanate is preferably used.
[0026] The above-described first polyester composition can be prepared, for
example, by
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heating a polyester having an intrinsic viscosity of not more than 0.55 dl/g
and an equivalent
spherical diameter of 1 mm to 50 mm at a temperature of a melting point of the
polyester
composition to a temperature lower than the melting point by 80 C under a
pressure-reduced
condition and/or an inert gas flowing condition.
[0027] In a case of polyethylene terephthalate, the above-described
temperature for heating
(heat treatment) is preferably not lower than 190 C and lower than 260 C,
particularly
preferably, not lower than 200 C and lower than 250 C .
[0028] Although the intrinsic viscosity of the polyester composition used in
the above-
described heat treatment is preferably not more than 0.55 dl/g, more
preferably polyester with
an intrinsic viscosity of not more than 0.50 dl/g is used from the viewpoint
of cyclic trimer
and color tone. The lower limit is not less than 0.35 dl/g. If less than 0.35
dl/g, because the
speed for increasing the viscosity at the time of heat treatment is too slow,
the productivity is
reduced.
[0029] In a case where the temperature for heat treatment is lower than 190 C,
the speed for
reducing the amount of cyclic compound becomes small. In a case of higher than
260 C, the
polymer is dissolved, and even if the heat treatment is carried out, the
amount of the cyclic
compound tends not to be reduced. Therefore, the heat treatment is carried out
preferably at
a temperature of not higher than the melting point of the polymer (polyester)
being heat
treated.
[0030] The time for heat treatment is usually not less than 2 hours and not
more than 60
hours, preferably not less than 3 hours and not more than 40 hours. In a case
where the time
is shorter than 2 hours, the effect for decreasing cyclic compound is small,
and in a case of
longer than 60 hours, the speed for decreasing cyclic compound becomes small,
and on the
contrary, a problem such as thermal deterioration becomes great.
[0031] In a case where the polyester composition with an intrinsic viscosity
of not more
than 0.55, it is important to carry out the heat treatment at a pressure-
reduced condition,
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preferably, at a condition of not higher than 133 Pa, and/or at an inert gas
flowing condition.
The inert gas may be inert relatively to polyester, for example, nitrogen,
helium, carbon
dioxide, etc. can be exemplified, and from the economic point, nitrogen is
preferably used.
[0032] In a case where the inert gas is used, the atmosphere at the time of
heat treatment is
important. Because oxidative decomposition or hydrolysis is likely to occur in
polyester by
oxygen and moisture, it is necessary to suppress oxygen and moisture in the
atmosphere.
The moisture content in the atmosphere is preferably not more than 1,000 ppm,
more
preferably not more than 500 ppm, and further preferably not more than 400
ppm. If the
moisture content in the atmosphere is more than 1,000 ppm, although cyclic
compound
decreases, at the same time, polyester is hydrolyzed and the intrinsic
viscosity of the obtained
polymer tends to decrease. On the other hand, it is preferred not to make the
moisture
content to be I ppm or less. Because, in a case where the moisture content is
not more than 1
ppm, not only the process becomes complicated in order to increase the purity
of the inert gas,
but also the speed for decreasing cyclic compound tends to be reduced.
Further, the oxygen
concentration is not more than 1,000 ppm, preferably not more than 500 ppm,
more preferably
not more than 100 ppm, most preferably not more than 50 ppm. In a case where
the oxygen
concentration is more than 1,000 ppm, polyester is likely to be deteriorated.
[0033] The apparatus for heat treatment used for the above-described heat
treatment is
preferably an apparatus capable of heating polyester uniformly. Concretely, a
ventilation
dryer, a rotary dryer, a fluidized dryer, dryers having various agitators,
etc. can be used.
[0034] Further, in the present invention, it is preferred to appropriately
remove moisture of
polyester before carrying out the heat treatment. Furthermore, it is more
preferred to
crystallize a part of polyester in order to prevent fusion of polymers to each
other at the time
of heat treatment.
[0035] In the present invention, it is preferred to add an antioxidant in
order to improve
coloring. As the antioxidant, a phenol-group antioxidant, a phosphorus-group
antioxidant,
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an amine-group antioxidant, lactone-group antioxidant, etc. are suitable.
[0036] As the phenol-group antioxidant, a compound can be used as long as it
has a phenol
structure and has at least one bulky group in the phenol ring. Concretely, a
compound
having the following structure is preferable.
[0037] [Chemical formula 1]
R2 R3
HO
R'
[0038] Where,
R1, R2: alkyl group, substitutional alkyl group, or substitutional triazole
group (respective
groups may be same or may be different from each other.)
R3: alkyl group, substitutional alkyl group, alkoxy group, or substitutional
amino group.
[0039] As examples of such a compound, there are 2,2'-methylenebis(4-methyl-6-
tert-
butylphenol), 1,6-hexanediolbis[3-(3,5-di-tert-butyl-4-
hydroxyphenyl)propionate],
pentaerythritoltetrakis[3,5-di-tert-butyl-4-hydroxyphenyl)propionate],
distearyl-3,5-di-tert-
butyl-4-hydroxybenzylphosphonate, 2,6,7-trioxa-l-phosphabicyclo[2,2,2]octa-4-
illmethyl3,5-di-tert-butyl-4-hydroxyhydrocinnamate, 3,5-di-tert-butyl-4-
hydroxyphenyl-3,5-
distearylthiotriazylamine, 2-(2'-hydroxy-3'-hydroxy-3',5'-di-tert-butylphenyl)-
5-
chlorobenzotriazole, 2,6-di-tert-butyl-4-hydroxymethylphenol, 1,3,5-trimethyl-
2,4,6-tris(3,5-
di-tert-butyl-4-hydroxybenzyl)benzene, 4,4'-methylenebis(2,6-di-tert-
butylphenol), 3,5-di-
tert-butyl-4-hydroxybenzyldiamine, N,N'-hexamethylenebis-3,5-di-tert-butyl-4-
hydroxyhidrocinnamide, etc. In particular, diethyl[[3,5-bis(1,1-dimethylethyl)-
4-
hydroxyphenul]methyl]phosphonate is preferable because of its excellent
effect. This
compound is sold on the market, for example, as "IRGANOX 1222" by Ciba
Specialty
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CA 02569001 2006-11-29
Chemicals Holding Inc.
[0040] As the phosphorus-group antioxidant, a compound containing a trivalent
phosphorus
and having at least one bulky group in the benzene ring is preferable.
Concretely, a
compound having the following structure is preferable.
[0041 ] [Chemical formula 2]
' O P
[0042] As examples of such a compound, there are bis[2,4-bis(1,1-
dimethylethyl)-6-
methylphenyl]ethylester phosphite, tetrakis(2,4-di-tert-butylphenyl)[1,1-
biphenyl]-4,4'-
diillbisphosphonite, bis(2,4-di-tert-butylphenyl)pentaerythritol-diphosphite,
bis(2,6-di-tert-
butyl-4-methylphenyl)pentaerythritol-diphosphite, 2-[[2,4,8,10-tetrakis(1,1-
dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphepine-6-yl]oxy]-, N,N-bis[2-
[[2,4,8,10-
tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphepine-6-yl]oxy]-
ethyl]ethaneamine, etc. These are sold on the market, for example, as "IRGAFOS
126", etc.
by Ciba Specialty Chemicals Holding Inc.
[0043] As the amine-group antioxidant, for example, a compound having the
following
structure is preferable.
[0044] [Chemical formula 3]
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CA 02569001 2006-11-29
A' !RR,
R
[0045] Where,
R: alkyl group (may be same or may be different from each other)
R': hydrogen or alkyl group
A': two or three-member alkylene ring (unsaturated or saturated)
[0046] A derivative of 2,2,6,6-tetramethylpiperidine is preferable. For
example, there are
4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-
tetramethylpiperidine, 4-
aryloyloxy-2,2,6,6-tetramethylpiperidine, 4-metoxy-2,2,6,6-
tetramethylpiperidine, 4-
benzoiloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-
tetramethylpiperidine, 4-
phenoxy-2,2,6,6-tetramethylpiperidine, 4-benzoxy-2,2,6,6-
tetramethylpiperidine, 4-
(phenylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine, etc. These are sold on the
market, for
example, as "FS042", etc. by Ciba Specialty Chemicals Holding Inc.
[0047] Further, the lactone-group antioxidant is also preferable, and for
example, 5,7-di-
tert-butyl-3-(3,4-dimethylphenyl)-3H-benzofuran-2-one is preferable.
These may be used individually or may be used as a mixture, and the amount
used is in a
range of 0.0001 to 1% by weight relative to the weight of polyester
composition, preferably in
a range of 0.001 to 0.1% by weight. By adding the antioxidant to the polyester
composition
in addition to be able to suppress the influence of oxygen involved at the
time of heat
treatment, the thermal resistance is increased and the deterioration of color
tone can be
improved although the reason is not clear.
[0048] It is preferred that the intrinsic viscosity of the polyester
composition containing the
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CA 02569001 2006-11-29
antioxidant is 0.4 dl/g or more. If the intrinsic viscosity is lower than 0.4
dl/g, a problem in
forming such as yarn cut at the time of spinning, film breakage at the time of
film formation or
breakage at the time of molding is liable to occur, and if the intrinsic
viscosity is too high, the
temperature is raised at the time of forming by the exothermic due to the
shear of molten resin,
or it is necessary to set a resin temperature for forming at a high
temperature in order to
improve the property for the melt forming, and as the result thereof, a cyclic
compound is
liable to be generated in a product. In particular, a polyester composition
having an intrinsic
viscosity of not less than 0.45 dl/g and not more than 0.90 dl/g is preferably
used.
[0049] In a case where the above-described antioxidant is used for the
polyester
composition, it is preferred that for the heat treatment the following
condition, which does not
change the intrinsic viscosity, is employed.
[0050] For example, in order to obtain a polyester composition with a constant
quality, it is
important to carry out the heat treatment in an atmosphere with a degree of
flowing of inert
gas of 1 liter/hr or less per 1 kg of polyester composition. Although
depending upon the
heating temperature, for example, in a case where the heating temperature is
not lower than
220 C, the degree of flowing (flow rate) is more preferably not more than 0.5
litter/hr.
Further preferably, it is not more than 0.1 litter/hr, and it may be a
resident state which causes
almost no flow. If the flow rate is more than 1 liter/hr per 1 kg of polyester
composition, the
intrinsic viscosity of the polymer increases, and it becomes difficult to
industrially obtain a
polyester composition with a constant quality.
[0051] The heat treatment is preferably carried out at a temperature in a
range of "a melting
point of the used polyester composition" to "a temperature lower than the
melting point by 80
C". In a case of a usual polyethylene terephthalate, the temperature is
preferably not lower
than 190 C and not higher than 260 C, and particularly preferably not lower
than 200 C and
not higher than 250 C. In a case where the temperature for heat treatment is
lower than 190
C, the reduction speed of cyclic compound is liable to become small. Further,
in a case of
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CA 02569001 2006-11-29
higher than 260 C, the polymer is molten, and even if the heat treatment is
carried out, cyclic
compound tends not to be decreased. Therefore, it is important to carry out
the heat
treatment at a temperature of not higher than the melting point of the
polyester composition.
[0052] The time for the heat treatment is usually not less than 2 hours and
not more than 60
hours, preferably not less than 3 hours and not more than 40 hours. In a case
where the time
is shorter than 2 hours, the effect for decreasing cyclic compound is small,
and in a case of
longer than 60 hours, the speed for decreasing cyclic compound becomes small,
and on the
contrary, a problem such as thermal deterioration becomes great.
[0053] The inert gas in the present invention may be inert relatively to
polyester, for
example, nitrogen, helium, carbon dioxide, etc. can be exemplified, and from
the economic
point, nitrogen is preferably used.
[0054] Because oxidative decomposition or hydrolysis is likely to occur in
polyester by
oxygen and moisture, it is important to control the oxygen and the moisture in
the inert gas
atmosphere. The moisture content in the atmosphere is preferably not more than
1,000 ppm
(by weight, hereinafter, in the present invention, "ppm" is defined by
weight), more preferably
not more than 500ppm, and further preferably not more than 400 ppm. If the
moisture
content in the atmosphere is more than 1,000 ppm, although cyclic compound
decreases, at the
same time, polyester is hydrolyzed and the intrinsic viscosity of the obtained
polymer tends to
decrease. Further, it is preferred not to make the moisture content to be I
ppm or less.
Because, in a case where the moisture content is not more than 1 ppm, not only
the process
becomes complicated in order to increase the purity of the inert gas, but also
the speed for
decreasing cyclic compound tends to be reduced. Further, the oxygen
concentration is not
more than 1,000 ppm, preferably not more than 500 ppm, more preferably not
more than 100
ppm, most preferably not more than 50 ppm. In a case where the oxygen
concentration is
more than 1,000 ppm, polyester is likely to be deteriorated.
[0055] Further, in the heat treatment, it is preferred to heat the polyester
at a condition, for
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CA 02569001 2006-11-29
example, where the inside of a heating bath is slightly pressurized by the
aforementioned inert
gas. The pressure of the atmosphere at the time of the heat treatment is
controlled preferably
at 1.03-4.9 x 105 Pa, more preferably at 1.07-1.96 x 105 Pa. In a case where
the atmosphere
pressure is less than 1.03 x 105 Pa, accompanying with movement of the
polyester
composition, oxygen and moisture in atmospheric air are likely to enter, and
it may cause a
reduction of intrinsic viscosity or may cause decomposition by oxidation or
hydrolysis.
Further, if more than 4.9 x 105 Pa, the apparatus becomes expensive.
[0056] Next, the second polyester composition will be explained.
In the second polyester composition according to the present invention, the
content of
cyclic trimer is in a range of 0.1 to 0.7% by weight. In a case where the
content of cyclic
trimer is more than 0.7% by weight, the cyclic trimer is likely to be
precipitated on the surface
of a film, etc., and the substances precipitated become a surface defect.
Further, the content
of cyclic trimer is preferably not more than 0.6% by weight from the viewpoint
of suppressing
the precipitation, more preferably not more than 0.4% by weight.
[0057] On the other hand, in a case where the content of cyclic trimer is less
than 0.1% by
weight, the time for heat treatment required for decreasing the cyclic trimer
becomes long,
and the thermal stability of the polyester tends to be damaged. Further, in a
case where the
content of cyclic trimer is less than 0.1% by weight, a remarkable advantage
by the cyclic
trimer is not particularly exhibited.
[0058] Because a cyclic trimer cannot be present in the crystallized part of
polyester, if the
crystallization of polyester progresses in a process for forming a film, it is
unevenly present
into the amorphous part. The cyclic trimer present locally in the amorphous
part at a high
concentration is in a condition easy to be precipitated to the surface of the
polyester, and when
the amount of the cyclic trimer becomes more than about 1.2% by weight, it is
precipitated.
Therefore, when the degree of crystallization of polyester is referred to as
c% (% by volume),
it is preferred that the content of cyclic trimer (% by weight) is smaller
than 1.2 x ((100 -
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CA 02569001 2006-11-29
c)/100). In a case of a film having a degree of crystallization of 50%, the
content of cyclic
trimer is preferably smaller than 0.6% by weight.
[0059] In the second polyester composition according to the present invention,
the content
of carboxylic end group is in a range of 15 to 40 equivalent/ton. If less than
15
equivalent/ton, a film is likely to slip in a process of film formation by
reduction of a property
for close contact between a stretching roller and the film, and the scratches
are likely to be
generated on the film surface, or the adhesive property of the film becomes
poor at the time of
processing the film surface. On the other hand, if more than 40
equivalent/ton, the color
tone of the polyester resin or the film becomes yellowish, and it becomes
difficult to employ
them for an optical use. The content is more preferably in a range of 15 to 35
equivalent/ton,
and most preferably in a range of 18 to 30 equivalent/ton.
[0060] In the polyester composition according to the present invention, the
intrinsic
viscosity is in a range of 0.55 to 0.80. In the present invention, the
intrinsic viscosity is a
viscosity determined at 25 C using orthochlorophenol as a solvent, if less
than 0.55, it causes
insufficient mechanical properties as a formed product, and if more than 0.8,
exothermic due
to shear at the time of extrusion becomes remarkable and thermal decomposition
of the
polymer may be induced. It is preferably in a range of 0.55 to 0.75, and most
preferably in a
range of 0.6 to 0.7.
[0061] In the second polyester composition according to the present invention,
an
absorbance at a wavelength of 365 nm of a solution prepared by dissolving 0.8g
of the
composition in 10 ml of orthochlorophenol is in a range of 0.22 to 0.36. 365
nm light is a
blue light, and when this light is much absorbed, the polymer becomes
yellowish. In a case
where the absorbance is more than 0.36, it becomes difficult to use the
polyester composition
or film for optical field. On the other hand, in order to achieve the
absorbance at a value less
than 0.22, it is necessary to sacrifice the productivity such as reducing the
amount of charged
raw material in the melting and polymerization of polyester, and it is
preferred to avoid this
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CA 02569001 2006-11-29
from the viewpoint of the balance between cost and quality. The absorbance is
preferably in
a range of 0.24 to 0.30.
[0062] In the second polyester composition according to the present invention,
it is
preferred that the content of bis(hydroxyethyl)terephthalate is in a range of
50 to 200 ppm
(hereinafter, unless not particularly described clearly, "ppm" means a value
determined by
weight). Although bis(hydroxyethyl)terephthalate is a kind of linear oligomer
of
polyethylene terephthalate, in a case where the content of the oligomer is
more than 50 ppm,
the forming property of polyester is preferably improved, and on the other
hand, in a case of
more than 200 ppm, the oligomer is sublimated in a processing process for
forming polyester,
and it frequently contaminates an apparatus and a product.
[0063] In the second polyester composition according to the present invention,
although the
polymerization catalyst is not particularly limited, it is preferred that
antimony element is
controlled in a range of 30 to 150 ppm and alkaline earth element is
controlled in a range of 1
to 80 ppm. If antimony element is less than 30 ppm, it becomes difficult to
decrease cyclic
trimer, and if more than 150 ppm, the cyclic trimer once decreased is likely
to be regenerated
at the time of melting polyester. If alkaline earth element is less than 1
ppm, because the
volume specific resistance at melting of polyester resin becomes high, it
becomes difficult to
apply an electrostatic casting to a process for making a film, and if more
than 80 ppm, the
cyclic trimer once decreased is likely to be regenerated at the time of
melting polyester.
[0064] In a case where the above-described antimony element is not used or it
is controlled
to be less than 30 ppm, it is preferred to use a titanium element compound as
the
polymerization catalyst. In this case, it is preferred to control titanium
element in a range of
0.5 to 50 ppm. If titanium element is less than 0.5 ppm, it becomes difficult
to decrease
cyclic trimer, and if more than 50 ppm, the cyclic trimer once decreased is
likely to be
regenerated at the time of melting polyester. As another catalyst, a germanium
compound
also can be used.
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CA 02569001 2006-11-29
[0065] As the antimony compound, antimony trioxide can be preferably used. In
a case of
titanium catalyst, titanium chelate compound or tetraalkoxy titanium compound
can be
preferably used. For example, titanium chelate such as titanium
acetylacetonate, titanium
tetraacetylacetonate, titanium octyleneglycolate, titanium lactate, titanium
ethylacetoacetate,
titanium citrate, titanium peroxocitrate and titanium ammonium, or
alkyltitanate such as
tetraisopropyltitanate, tetrabutyltitanate, tetra(2-ethylhexyl)titanate and
tetramethyltitanate
can be exemplified, and among these, titanium chelate or tetrabutyltitanate is
preferably used.
[0066] In the second polyester composition according to the present invention,
it is
preferred that the degree of crystallization is in a range of 50 to 95% (by
volume), and the bulk
density is in a range of 0.5 to 1.0 kg/liter. In a case of high degree of
crystallization, cyclic
trimer can be decreased more efficiently. In a case where the degree of
crystallization is less
than 50%, it becomes difficult to decrease the content of cyclic trimer.
Further, in order to
achieve the degree of crystallization at a value more than 95%, it is
necessary to heat polyester
chips for a long time, and it is liable to induce a thermal deterioration of
polyester resin. In a
case where the bulk density of the polyester resin chips is less than 0.5
kg/liter, inconvenience
is likely to be caused in transportation or handling of chips, and in a case
of more than 1.0
kg/liter, because cyclic trimer in the chips is decreased, the chips are
liable to be colored when
heat treated.
[0067] The process for obtaining the above-described second polyester
composition will be
shown hereunder.
In a first process for producing the second polyester composition according to
the
present invention, a polyester having an intrinsic viscosity of 0.4 to 0.7 and
a degree of
crystallization of not less than 30% is heated at a temperature of 190 C to
250 C for 0.5 to 60
hours under an inert gas atmosphere having a pressure of 650 to 1,020 hPa.
[0068] For the inert gas atmosphere, for example, noble gas such as helium,
neon, argon,
etc. and nitrogen gas or carbon dioxide gas can be employed. Among these,
nitrogen gas can
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CA 02569001 2006-11-29
be easily gotten, and it can be preferably used. It is preferred that the
concentration of
oxygen or moisture is controlled to be not more than 500 ppm by volume. In a
case where
the concentration of oxygen or moisture is more than 500 ppm, the polyester is
likely to be
deteriorated, and it may cause coloring of the polyester.
[0069] The pressure of the inert gas atmosphere is controlled in a range of
650 to 1,020 hPa.
In a case of less than 650 hPa, because solid-phase polymerization progresses,
the degree of
polymerization of the polyester increases. The increase of the polymerization
degree causes
increase of melt viscosity of the polyester resin, exothermic due to shear at
the time of melt
forming the resin becomes violent, and deterioration of the polyester resin is
liable to occur.
Further, in a case of less than 650 hPa, the content of
bis(hydroxyethyl)teraphthalate is likely
to be decreased, and the forming property of the polyester resin is also
likely to become bad.
On the other hand, in a case where the pressure of the inert gas atmosphere is
more than 1,020
hPa, thermal decomposition of polyester is likely to occur. In a case being
treated at a
pressurized condition, as described later, it is important to flow the inert
gas atmosphere at a
specified flowing degree. The pressure is preferably in a range of 800 to
1,020 hPa, more
preferably in a range of 850 to 1,000 hPa.
[0070] The intrinsic viscosity of the polyester carried out with heat
treatment is in a range of
0.4 to 0.7. If lower than 0.4, although cyclic trimer is liable to be
decreased, a polyester
formed product obtained becomes poor in mechanical properties. In a case where
the
intrinsic viscosity is higher than 0.7, the speed for decreasing cyclic trimer
is slow, a long-
time heat treatment becomes necessary, and it is economically disadvantageous.
The
intrinsic viscosity is preferably in a range of 0.5 to 0.7, more preferably in
a range of 0.55 to
0.68. A polyester resin having an intrinsic viscosity in such a range can be
obtained by
controlling polymerization agitating torque in a usual melt polymerization.
[0071] In the polyester resin to be carried out with heat treatment, the
degree of
crystallization is not less than 30%. Because cyclic trimer exists in the
amorphous part of
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CA 02569001 2006-11-29
the polyester resin, when the crystallization progresses, the cyclic trimer is
concentrated into
the amorphous part. In the polyester with such a condition, because the cyclic
trimer having
been supersaturated in the amorphous part is decreased down to an equilibrium
amount, the
amount of cyclic trimer as the whole of the polyester resin can be decreased.
In a case where
the degree of crystallization is less than 30%, because the degree of
supersaturation of cyclic
trimer in the amorphous part is insufficient, a great effect for decreasing
the cyclic trimer
cannot be expected. Where, the degree of crystallization can be increased even
during heat
treatment, it is preferred to finally achieve a degree of crystallization of
not less than 70%.
In the process for achieving a degree of crystallization of not less than 30%,
it is preferred to
provide a process for crystallization treatment before the heat treatment, and
for example, it is
preferred to heat the polyester resin at 120 to 180 C for a time of 2 hours or
more under a
pressure-reduced condition and a condition being flowed with hot air. This
process may be
set together with a drying process. The degree of crystallization of polyester
resin can be
confirmed by change of density, and for example, when the density of the
completely
amorphous part is referred to as 1.335 g/cm3 and the density of the
crystallized part is referred
to as 1.455 g/cm3, it is determined by the following equation.
Degree of crystallization=(chip density-1.335)/(1.455-1.335)
[0072] The temperature for carrying out the heat treatment is in a range of
190 C to 250 C.
If lower than 190 C, because the speed for decreasing oligomer is low, the
time for the
treatment becomes long and it is disadvantageous economically, and if the
treatment
temperature is higher than 250 C, fusion of the polyester resin is likely to
occur, and because
thermal deterioration also occurs, the coloring of polyester becomes violent.
The
temperature is preferably in a range of 200 C to 240 C, more preferably in a
range of 220 C
to 235 C.
[0073] The time for the heat treatment is in a range of 0.5 to 60 hours.
Although the time
varies depending on the residual amount of polymerization catalyst and the
treatment
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CA 02569001 2006-11-29
temperature, if less than 0.5 hour, it is difficult to sufficiently decrease
cyclic trimer, and if
more than 60 hours, it becomes economically disadvantageous. Although only
cyclic trimer
can be decreased without increasing the degree of polymerization of polyester
and without
coloring by the above-described process, the production may be carried out by
the following
second process.
[0074] In the second process for producing a polyester resin composition, a
polyester having
an intrinsic viscosity of 0.4 to 0.7 and a degree of crystallization of not
less than 30% is heated
at a temperature of 190 C to 250 C for 0.5 to 60 hours, while an inert gas at
a pressure of
1,020 hPa to 0.5 MPa is flowed at not less than 1 liter/hr per 1 kg of the
polyester.
[0075] The intrinsic viscosity, degree of crystallization, treatment
temperature and time are
similar to those in the first process, but in this second process, the
treatment is carried out
while the inert gas at a pressure of 1,020 hPa to 0.5 MPa is flowed at not
less than 1 liter/hr per
1 kg of the polyester. As the inert gas, a gas similar to that in the first
process can be chosen,
and the concentration of oxygen and the concentration of moisture are also
controlled
preferably in ranges similar to those in the first process. Where, the flowing
amount of inert
gas in the present invention means an amount at a standard condition, and the
standard
condition means a condition at a pressure of 1,013 hPa and a temperature of 0
C.
[0076] In a case where the pressure of inert gas is lower than 1,020 hPa,
because solid-phase
polymerization progresses if the inert gas flows, the degree of polymerization
of the polyester
resin increases. On the other hand, even if the pressure is controlled at a
high pressure more
than 0.5 MPa, it is not particularly effective for decreasing oligomer, and it
is economically
disadvantageous. The pressure is preferably in a range of 0.12 MPa to 0.4 MPa,
and more
preferably in a range of 0.15 MPa to 0.35 MPa. By flowing the inert gas at a
pressurized
condition, thermally deteriorated substances such as acetoaldehyde generated
from polyester
is discharged to outside of the system, and because ethylene glycol and the
like is hard to be
discharged at a pressurized condition, increase of polymerization degree can
be suppressed
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CA 02569001 2006-11-29
while coloring is suppressed, and cyclic trimer can be decreased. This
advantage is
exhibited by the fact in that, although the vapor pressure of acetoaldehyde at
the temperature
of the heat treatment exceeds 0.5 MPa, the vapor pressure of ethylene glycol
is not more than
0.5 MPa.
[0077] The third production process is a process for replacing an atmosphere
for heat
treatment intermittently.
Concretely, it is a process wherein a process (A) for heat treating a
polyester at a
temperature of 190 C to 250 C for 15 minutes to 10 hours under a condition of
an inert gas
atmosphere having a degree of flow of inert gas of not more than 1 liter/hr
per 1 kg of the
polyester and a process (B) for renewing the inert gas atmosphere by replacing
the inert gas
atmosphere within 15 minutes are repeated alternately, and the total time of
the processes (A)
and (B) is set at 0.5 to 60 hours. Because the inert gas atmosphere almost
does not move in
the process (A), the intrinsic viscosity of the polyester composition during
the heat treatment
almost does not change. On the other hand, a fine amount of by-product such as
acetoaldehyde generated in the process (A) is discharged out of the apparatus
by the process
(B), and it is prevented that the polyester composition is colored or
deteriorated.
[0078] In the process (B), a method for filling the heat treatment apparatus
with a new inert
gas wherein after once making the inside of the heat treatment apparatus a
vacuum condition,
a method for replacing the inert gas by flowing the inert gas at a volume more
than the volume
of the treatment bath, etc. can be employed. It is preferred to complete the
process (B)
within 15 minutes, and if more than 15 minutes, there is a case where the
intrinsic viscosity of
the polyester composition increases.
[0079] After the atmosphere for heat treatment is renewed by the process (B),
the condition
may be transferred to the condition of the process (A) as it is and the
process (A) may be
carried out.
[0080] In the first, second and third production processes according to the
present invention,
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CA 02569001 2006-11-29
in a case where a heating bath for heating polyester is used, it is preferred
that the capacity of
the heating bath (capacity of the interior of the bath) is set at not less
than 150% of an apparent
volume of the polyester resin. If the capacity of the bath is less than 150%,
the polyester is
likely to be colored by the heat treatment.
[0081] For example, in a case where the capacity of the bath is 150 liters, if
polyester resin
with an apparent specific gravity of 0.7 is deposited into the bath, the
apparent volume of the
polyester resin becomes a value corresponding to 100 liters, and the capacity
of the bath
becomes 150%. The capacity of the bath is more preferably 200% or more, and
most
preferably 250% or more. On the other hand, if more than 500%, such a capacity
of bath
reduces the productivity, and a particular advantage for color tone of
polyester cannot be
expected by such a capacity.
[0082] As the heat treatment apparatus used for the above-described heat
treatment, an
apparatus capable of heating polyester uniformly is preferable. Concretely, a
ventilation
dryer, a rotary dryer, a fluidized dryer, dryers having various agitators,
continuous tower
dryer, etc. can be used.
[0083] The polyester film prepared from the polyester resin composition
according to the
present invention is suitable for a magnetic recording medium, or films for
optical field, for
being laminated with a steel plate and for wrapping, because cyclic trimer is
hard to be
precipitated to the film surface even in a case of a long-term storage and
further cyclic trimer
is hard to be precipitated to the film surface even if the film is treated at
a heating condition.
In a case where it is wished to suppress the precipitation of cyclic trimer
only on a specified
surface of a film, a formation of a laminated film can also be employed. If
the polyester
resin according to the present invention is laminated, the precipitation of
cyclic trimer can be
suppressed not only on the laminated surface but also a surface which is not
laminated. In a
case of lamination, it is preferred that at least one surface contains the
above-described
polyester resin composition according to the present invention.
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CA 02569001 2006-11-29
[0084] Next, the process for producing the first and second polyester
compositions
according to the present invention will be explained raising examples.
[0085] Polyethylene terephthalate can be produced, for example, by any of the
following
processes. Namely, they are (1) a process for using terephthalic acid and
ethylene glycol as
raw materials, preparing a low-molecular polymer by direct esterification and
preparing a
high-molecular polymer by successive condensation polymerization, and (2) a
process for
using dimethylterephthalate and ethylene glycol as raw materials, preparing a
low-molecular
polymer by transesterification and preparing a high-molecular polymer by
successive
condensation polymerization. In the present invention, any of processes (1)
and (2) can be
employed. Further, as needed, an antioxidant, an antiblocking agent, etc. can
be added
before reaction or during reaction.
[0086] In the present invention, a process can be employed for adding an
antioxidant at an
arbitrary stage in the reaction of the process (1) or (2), carrying out
condensation
polymerization and preparing a high-molecular polyethylene terephthalate.
[0087] Further, although the above-described reaction is carried out by a
batch process, a
semi-batch process or a continuous process, the production process according
to the present
invention can be adapted to any type process of the processes. Further, the
antioxidant may
be added by kneading it after completing polymerization.
[0088] The intrinsic viscosity of the polyester resin can be determined by an
agitating
torque at a finishing point of polymerization. In a case of a high agitating
torque, the melt
viscosity of the polymer is high, and the intrinsic viscosity also becomes
high. The agitating
torque for determining the finishing point of a polymerization apparatus may
be set so as to
achieve an aimed intrinsic viscosity.
[0089] The polyester resin prepared and finished in polymerization may be
discharged from
a lower portion of the polymerization apparatus in a form of strand, and it
may be cut by a
cutter while being cooled by water. Because the shape of chips can be
controlled by cutting,
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CA 02569001 2006-11-29
polyester chips having a desirable bulk density for the present invention can
be obtained.
[0090] It is preferred that the polyester resin obtained is dried before heat
treatment. The
drying may be carried out by heating the chips at 120 C to 180 C for a time of
not less than 2
hours under a pressure-reduced condition or a hot air flowing condition. By
such a drying
process, the degree of crystallization of the polyester resin can be increased
up to a value of
not less than 30%.
[0091] The polyester resin completed with the drying is successively served to
heat
treatment, and the polyester resin completed with the heat treatment is cooled
and taken out
from the bath.
[0092] The above-described polyester composition can be suitably used as a
film. In
particular, it is preferred to make a laminated film having a main layer and a
sub layer. The
laminated film can be produced, for example, by melting polyesters (A) and
(B), respectively.
In this case, the melting temperatures are not particularly limited, and
temperatures having no
inconvenience for extruding the polyesters (A) and (B) from dies may be
employed. Then,
the molten polyesters (A) and (B) are laminated to each other to form a
laminated sheet. As
the method for lamination, although any of a method, a so-called coextrusion
method, for
joining and lamination the polyesters (A) and (B) between extruders and a die
or in a die, and
discharging it from the die as a laminated sheet, and a method for discharging
the polyesters
(A) and (B), respectively, in sheet forms from different dies each having a
slit, and laminating
both sheets, may be employed, the coextrusion method is preferred. Where,
although the
laminated sheet may have at least laminated layers of polyesters (A) and (B),
a two-layer
structure of (A)/(B) and a three-layer structure of (A)/(B)/(A) or (B)/(A)/(B)
can be employed.
In particular, a three-layer structure is preferable. At that time, the film
may be formed by
only the polyester according to the present invention, or a process for mixing
the polyester
composition according to the present invention into another polyester
composition at a
content of not less than 1% by weight and preparing a film changed with a
metal concentration
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CA 02569001 2006-11-29
is also preferred from the viewpoint of the productivity of other type films
or thermal
resistance.
[0093] For the coextrusion method for lamination, a feedblock, a static mixer,
a
multimanifold die, etc. can be used. Although a pipe mixer, a square mixer,
etc. can be
exemplified as the static mixer, a square mixer is preferable in the present
invention.
Further, it is preferred that a layer comprising the polyester resin
composition according to the
present invention forms at least one surface from the viewpoint of foreign
materials.
[0094] The laminated sheet thus obtained is drawn by one of various kinds of
movable
cooling bodies, preferably, a rotating drum, and at the same time,
electrostatic charge is
applied to the sheet, and the sheet is cooled and solidified by the movable
cooling body. The
method for applying electrostatic charge to the sheet is not particularly
limited. For
example, a method for providing a wire electrode near a position between a die
and the
movable cooling body and at a position above the sheet surface on the side
which does not
come into contact with the movable cooling body, and applying a voltage
between the wire
electrode and the movable cooling body, etc. can be employed. The cooled and
solidified
laminated sheet, that is, a non-stretched sheet, is then stretched uniaxially
or biaxially by one
of various stretching processes, for example, a roller stretching process or a
tenter stretching
process, and this is wound. The order of stretching may be either sequential
or
simultaneous.
[0095] Here, the stretching in the longitudinal direction means a stretching
for giving a
molecular orientation in the longitudinal direction to the film, for example,
it is carried out by
circumferential speed difference between rollers. This stretching may be
carried out at a
single stage, and further, may be carried out at multi stages using a
plurality of pairs of rollers.
The draw ratio of the stretching is preferably in a range of 2 to 15 times,
more preferably in a
range of 2.5 to 7 times.
[0096] The stretching in the transverse direction means a stretching for
giving an orientation
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CA 02569001 2006-11-29
in the transverse direction to the film, for example, it is carried out by
using a tenter, and
stretching the film in the transverse direction by conveying the film at a
condition where both
sides of the film are grasped by clips. The draw ratio of the stretching is
preferably in a
range of 2 to 10 times.
[0097] In a case of simultaneous biaxial stretching, while the film is
conveyed in a tenter
while both sides of the film are grasped by clips, the film is stretched
simultaneously in the
longitudinal and transverse directions, and this process may be employed.
[0098] The film thus biaxially stretched is preferably heat treated in the
tenter at a
temperature of not lower than the stretching temperature and not higher than
the melting point
in order to give a dimensional stability, and the film is gradually cooled
uniformly to a room
temperature, and then wound. In the present invention, the temperature for the
heat
treatment is preferably in a range of 120 to 240 C from the viewpoints of
flatness,
dimensional stability, etc.
[0099] Although the thickness of the laminated polyester film according to the
present
invention is not particularly limited, it is preferably in a range of 0.5 to
100 m, in particular,
more preferably in a range of 1 to 80gm.
[0100] Further, in a case where a layer such as an easy adhesion layer or a
layer containing
particles is formed, using a coating technology such as gravure coating or
metering bar type
coating, a coating component may be applied at an in-line condition before
stretching or
between the longitudinal stretching and the transverse stretching, and an off-
line coating after
stretching may be employed.
[0101] The polyester composition and polyester film according to the present
invention are
effective particularly for use for magnetic recording media such as magnetic
tapes, for use for
optical base materials such as optical films, or for use for being laminated
with a steel plate.
Examples
[0102] Hereinafter, the present invention will be explained in more detail by
examples.
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CA 02569001 2006-11-29
The first polyester composition is shown as follows.
[0103] (1) Determination of cyclic trimer in polyester:
mg of polyester was dissolved in 1 ml of 1,1,2,2,-tetrachloroethane by heating
at 200
C for 10 minutes in a glass ampoule, after cooling, the content was diluted by
chloroform up
to 25 ml, and the obtained solution was analyzed referring to chloroform as a
developing
solvent by using a high-speed liquid chromatograph HLC-802UR produced by Toyo
Soda
Corporation.
[0104] (2) Intrinsic viscosity:
It was determined at 25 C using orthochlorophenol.
[0105] (3) Color tone of polymer:
It was determined using a color-difference meter produced by Suga Tester
Corporation
(SM color computer, type SM-3), at L, a and b hunter values.
[0106] (4) Concentration of carboxylic end group:
A polymer was dissolved in orthocresol/chloroform (weight ratio: 7/3) at 90 to
100 C,
and the concentration was determined by measuring an electric potential
difference by alkali.
[0107] (5) Forcible oligomer precipitation test:
After a film having a square shape with vertical and transverse sizes of 5 cm
was heated
in an atmospheric air at 150 C for 30 minutes, it was deposited with Al, it
was observed by a
differential interference microscope at a magnification of 200 times, and an
amount of
precipitation of cyclic trimer with a size of not less than 1 m per 1 mm2 was
counted.
[0108] (6) Degree of crystallization:
A density d was determined at 25 C, using a density gradient tube comprising a
sodium
bromide aqueous solution. From the obtained value, the degree of
crystallization was
calculated using the following equation.
Degree of crystallization (%)=(d-1.335)/(1.455-1.335) x 100
[0109] (7) Number of large foreign matters in polyester composition
(number/mg) (number
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CA 02569001 2006-11-29
density of particles containing Ti, Sb and Ge elements):
After chips were cleaned by ultrasonic washing with (concentrated hydrochloric
acid:purified water = 1:1) for one minute in a clean room of class 100, they
were cleaned by
ultrasonic washing with purified water for one minute, thereafter, they were
dissolved on a
cover glass of a hot plate, a sample was made by placing a cover glass thereon
so as not to
involve air bubbles, it was measured at 4 fields of view by dark field method
(magnification:
450 times) using a digital microscope produced by Keyence Corporation (VHZ-
450), and it
was observed as average value. Cut lines were defined on the polymer thin film
on a
preparation by a sharp razor at 10 lines x 10 rows to make totally 100 of
measures. A defect
having a maximum diameter of not less than 1 m was determined as a foreign
matter.
Foreign matters in 0.02g of chip were determined from a field of view of
0.0034 em2 and a
thickness of 40 m. Further, the preparation was carbon deposited after the
polymer thin
film portion was served to plasma ash treatment, measures, in which particles
counted as not
less than I m by an optical microscope existed, were observed by SEM-XMA, and
presence
of Ti, Ge and Sb elements contained in the particles was confirmed. Thus, a
value obtained
by converting the number of particles containing Ti, Ge and Sb elements with a
size of not
less than 1 m into a value per 1 mg of polymer was defined as the particle
number density.
Where, the maximum diameter is referred to as a maximum length of an observed
defect.
[0110] (8) Content of alkali metal such as lithium in polyester (atomic
absorption method):
It was determined by atomic absorption method using a polarizing-type Zeeman
atomic
absorption photometer produced by Hitachi Co., Ltd., type: 180-80 (frame:
acetylene-air).
8g of polymer was atomized by frame system using a hollow cathode ray lamp as
a light
source, rays were detected at the ray measuring part, and the measured value
was converted
into the content of metal using a calibration curve prepared in advance.
[0111 111] Content of metal such as titanium element, antimony element and
germanium
element in polyethylene terephthalate:
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CA 02569001 2006-11-29
It was determined by fluorescent X-ray spectrometer (produced by Horiba
Seisakusho
Corporation, type MESE-500W) or ICP emission spectrometer (produced by Seiko
instruments Corporation, SPS1700). Where, as needed, in order to remove
influence due to
inorganic particles such as titanium oxide particles in the objective
polyethylene
terephthalate, fluorescent X-ray spectroscopy or ICP emission spectroscopy was
carried out
after the following pretreatment. Namely, polyethylene terephthalate was
dissolved in
orthochlorophenol, and after the viscosity of the polymer solution was
adjusted by chloroform
as needed, the particles were settled by a centrifugal separator. Thereafter,
only the
supernatant liquid was recovered by gradient method, polymer was re-
precipitated by adding
acetone, filtrated and washed to prepare polymer removed with particles. With
respect to
such a polymer prepared by removing particles by the pretreatment, the amount
of metal such
as titanium element, antimony element and germanium element was determined.
[0112] (10) Equivalent spherical diameter:
Here, the equivalent spherical diameter means a diameter of a sphere having
the same
volume as that of polyester composition (particle, chip), the volume was
determined by
dividing the weight of polyester composition with a complete amorphous density
of the
polyester composition (do=1.335 g/cm3), and the diameter of the sphere was
determined
therefrom.
[0113] (Reference Example) Process for synthesizing titanium lactate sodium
chelate
compound:
Lactic acid (226.8g, 2.52 mol) was dissolved in hot water (371 g) in a flask
of 3L having
an agitator, a condenser and a thermometer. Titanium tetraisopropoxide (285g,
1.00 mol)
was slowly added to this solution being agitated, from a drop funnel. This
mixture was
heated and circulated for one hour to prepare a cloud solution, and by this,
isopropanol/water
mixture was distilled under a pressure-reduced condition. The product was
cooled down to a
temperature lower than 70 C, and then, aqueous solution containing NaOH (380g,
3.04 mol)
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CA 02569001 2006-11-29
at 32% by weight was slowly added to this solution being agitated, from a drop
funnel. The
obtained product was filtered, then mixed with ethylene glycol (504g, 8 mol),
thereafter
heated under a pressure-reduced condition to remove isopropanol/water, and a
slightly cloud
light yellow product (Ti content: 5.6% by weight) was obtained (titanium
lactate sodium
chelate compound).
[0114] Example 1:
A slurry of 100 kg of high-purity terephthalic acid (produced by Mitsui
Chemical
Corporation) and 45 kg of ethylene glycol (Japan Catalyst Corporation) was
supplied to an
esterification bath, which was charged with about 123 kg of
bis(hydroxyethyl)terephthalate
beforehand and which was kept at a temperature of 250 C and a pressure of 1.2
x 105 Pa, in
order for 4 hours, and even after completion of the supply, esterification was
further carried
out for one hour, 123 kg of this esterified product was transferred to a
condensation
polymerization bath.
[0115] Successively, to the above-described condensation polymerization bath
transferred
with the esterified product, titanium lactate sodium chelate was added by 10
ppm at a content
converted into a weight of titanium atoms, thereafter, phosphoric group
antioxidant "PEP45"
(registered trade mark) was added at 100 ppm relative to polymer, magnesium
acetate solution
was added by 70 ppm at a weight of magnesium atoms, phosphoric acid as a
phosphoric
compound was added by 10 ppm at a weight of phosphorus atoms, and thereafter,
while
agitating the low molecular polymer at 30 rpm, the reaction system was
gradually heated from
250 C to 285 C and the pressure was reduced down to 40 Pa. The times for
reaching the
final temperature and the final pressure were both set at 60 minutes. At the
time reaching a
predetermined agitating torque, the reaction system was purged with nitrogen
to return to a
normal pressure and the condensation polymerization was stopped, the polymer
was
discharged into a cooled water in a strand-like form and immediately cut to
obtain columnar
chips with a diameter of about 4 mm and a length of about 6 mm (the equivalent
spherical
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CA 02569001 2006-11-29
diameter of the polymer was 5.4 mm). Where, the time from start of pressure
reduction to
reaching the predetermined agitating torque was 2 hours. The intrinsic
viscosity of the
obtained polymer was 0.500 dl/g, and the amount of cyclic trimer in the
polymer was 1.1% by
weight.
[0116] This polymer was dried at 150 C under a pressure-reduced condition, and
then, it
was heat treated at a pressure-reduced condition (not higher than 133 Pa) and
at a temperature
of 240 C for 8 hours, thereafter, the polymer was taken out. The intrinsic
viscosity of the
obtained polymer was 0.620 dl/g. Further, the amount of cyclic trimer in the
polymer was
0.30% by weight (this polymer is referred to as "polyester composition (A)).
[0117] Example2:
The heat treatment was carried out in a manner similar to that in Example 1
other than a
condition where the predetermined torque in Example 1 was set low and after
completion of
polymerization chips with an intrinsic viscosity of 0.45 dl/g were heat
treated, and a polymer
with an intrinsic viscosity of 0.58 dl/g and an amount of cyclic trimer of
0.25% by weight was
obtained (this polymer is referred to as "polyester composition (B)).
[0118] Example3:
The heat treatment was carried out in a manner similar to that in Example 1
other than a
condition where the predetermined torque in Example 1 was set low and after
completion of
polymerization chips with an intrinsic viscosity of 0.40 dl/g were heat
treated, and a polymer
with an intrinsic viscosity of 0.53 dl/g and an amount of cyclic trimer of
0.20% by weight was
obtained (this polymer is referred to as "polyester composition (C)).
[0119] Example4:
The heat treatment was carried out in a manner similar to that in Example 1
other than a
condition where antimony trioxide was added at a content of 200 ppm as a value
converted
into an amount of antimony instead of titanium lactate sodium chelate in
Example 1 and the
obtained chips with an intrinsic viscosity of 0.550 dl/g were heat treated,
and a polymer with
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CA 02569001 2006-11-29
an intrinsic viscosity of 0.700 dl/g was obtained. The amount of cyclic trimer
in the polymer
was 0.40% by weight (this polymer is referred to as "polyester composition
(D)).
[0120] Comparative Example 1:
Chips with an intrinsic viscosity of 0.75 dl/g were obtained in the same
manner as that
in Example I other than a condition where the predetermined torque in Example
1 was set
high and after completion of polymerization chips with an intrinsic viscosity
of 0.600 dl/g
were heat treated. The amount of cyclic trimer in the polymer was 0.50% by
weight (this
polymer is referred to as "polyester composition (E)).
[0121] Comparative Example 2:
Chips with an intrinsic viscosity of 0.530 dl/g were obtained in the same
manner as that
in Example I other than a condition where without adding magnesium acetate
chips with an
intrinsic viscosity of 0.450 dl/g were obtained after completion of
polymerization and the
chips were heat treated. The amount of cyclic trimer in the polymer was 0.45%
by weight
(this polymer is referred to as "polyester composition (F)).
[0122] Example 5:
Polyester composition (A) obtained in Example 1 was dried under a pressure-
reduced
condition of 133 Pa at 180 C for 3 hours, supplied to an extruder for a main
layer (layer A),
melt extruded onto a casting drum, and rapidly cooled and solidified at a
condition brought
into contact with the casting drum having a surface temperature of 25 C while
applying static
electricity onto the casting drum, and a single layer film was prepared.
Successively, this
non-stretched film was stretched in the longitudinal direction by a roller-
type stretching
machine at 90 C at a draw ratio of 3.5 times, and further, stretched in the
transverse direction
by using a tenter at 105 C at a draw ratio of 3.5 times, and after heat
treatment under a
constant length condition at 200 C for ten seconds, relax treatment was
carried out by 2% in
the transverse direction, and thus, a single layer polyester film having a
thickness of 8 m was
obtained. The property for forming a film was good. When the film thus
obtained was
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CA 02569001 2006-11-29
served to the forcible oligomer precipitation test, precipitated cyclic trimer
almost does not
exist and the color tone was good. The result is shown in Table 2.
[0123] Example 6:
Using two extruders, polyester composition (A) obtained in Example 1 was dried
under
a pressure-reduced condition of 133 Pa at 180 C for 3 hours, and supplied to
an extruder for a
main layer (layer A). Further, after polyester composition (B) obtained in
Example 2 was
dried under a pressure-reduced condition of 133 Pa at 180 C for 3 hours, it
was supplied to an
extruder for a sub layer (layer B) and was joined in a T-die, the polymer was
melt extruded
from a two-layer die onto a casting drum, it was rapidly cooled and solidified
at a condition
brought into contact with the casting drum having a surface temperature of 25
C while
applying static electricity onto the casting drum, and a two-layer non-
stretched film of A/B
type (thickness ratio: 6/1) was prepared. Successively, this non-stretched
film was stretched
in the longitudinal direction by a roller-type stretching machine at 90 C at a
draw ratio of 3.5
times, and further, stretched in the transverse direction by using a tenter at
105 C at a draw
ratio of 3.5 times, and after heat treatment under a constant length condition
at 200 C for ten
seconds, relax treatment was carried out by 2% in the transverse direction,
and thus, a
laminated polyester film having a thickness of 8gm was obtained (lamination
thickness of
layer B: 1.14gm). The property for forming a film was good. When the film thus
obtained
was served to the forcible oligomer precipitation test, precipitated cyclic
trimer almost does
not exist and the color tone was good. The result is shown in Table 2.
[0124] Example 7:
Polyester composition (D) obtained in Example 4 was dried under a pressure-
reduced
condition of 133 Pa at 180 C for 3 hours, supplied to an extruder for a main
layer (layer A),
melt extruded onto a casting drum, and rapidly cooled and solidified at a
condition brought
into contact with the casting drum having a surface temperature of 25 C while
applying static
electricity onto the casting drum, and a single layer film was prepared.
Successively, this
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CA 02569001 2006-11-29
non-stretched film was stretched in the longitudinal direction by a roller-
type stretching
machine at 90 C at a draw ratio of 3.5 times, and further, stretched in the
transverse direction
by using a tenter at 105 C at a draw ratio of 3.5 times, and after heat
treatment under a
constant length condition at 200 C for ten seconds, relax treatment was
carried out by 2% in
the transverse direction, and thus, a single layer polyester film having a
thickness of 8 m was
obtained. The property for forming a film was good. When the film thus
obtained was
served to the forcible oligomer precipitation test, precipitated cyclic trimer
almost does not
exist and the color tone was good. The result is shown in Table 2.
[0125] Comparative Example 3:
A polyester composition was supplied to an extruder in the same manner as that
in
Example 5 other than a condition where the polyester composition (E) obtained
in
Comparative Example I was supplied instead of the polyester composition (A).
The
extrusion could not be carried out because of too high viscosity, and a film
could not be
formed.
[0126] Comparative Example 4:
A polyester composition was supplied to an extruder in the same manner as that
in
Example 4 other than a condition where the polyester composition (F) obtained
in
Comparative Example 2 was supplied instead of the polyester composition (A).
The
property for applying static electricity was bad, air was involved, and the
speed for production
could not be increased.
[0127] [Table 1]
-37-
Intrinsic Intrinsic Number of
Cyclic trimer viscosity Color tone Degree of
viscosity after large foreign Ma+2xMd-3 Polyester
before heat crystallization
Content in heat treatment materials xMp composition
treatment L a b (o ~0)
polymer (wt%) (dl/g) (dl~g) (number/mg)
Example 1 0.30% 0.5 0.62 59.5 0.1 7.5 250 77 4.8 A
Example 2 0.25% 0.45 0.58 61 -0.15 6.5 300 80 4.8 B
Example 3 0.20% 0.4 0.53 62 0 6 250 85 4.8 C
Example 4 0.40% 0.55 0.7 55 2 3.5 10000 70 4.2 D
0
N
Comparative 0.50% 0.6 0.75 60.3 -0.1 8 250 62 4.8 E o
Example 1 0
~
N
0
p o,
~ Bxam~lei2e 0.45% 0.45 0.53 61 3 5 250 65 -1.0 F ~
~
~
N
tD
CA 02569001 2006-11-29
[0128] [Table 2]
Polymer composition Amount of Note
precipitation of cyclic
Layer A Layer B trimer (number/mm2)
polyester
Example 5 0
composition A
Example 6 polyester polyester 0
composition A composition B
Exam le 7 polyester 0 many foreign materials
p composition D
Comparative polyester cannot be determined cannot be formed as a film
Example 3 composition E
Comparative polyester cannot be determined cannot be formed as a film
Example 4 composition F
[0129] Example 8:
A slurry of 100 kg of high-purity terephthalic acid (produced by Mitsui
Chemical
Corporation) and 45 kg of ethylene glycol (Japan Catalyst Corporation) was
supplied to an
esterification bath, which was charged with about 123 kg of
bis(hydroxyethyl)terephthalate
beforehand and which was kept at a temperature of 250 C and a pressure of 1.2
x 105 Pa, in
order for 4 hours, and even after completion of the supply, esterification was
further carried
out for one hour, 123 kg of this esterified product was transferred to a
condensation
polymerization bath.
[0130] Successively, to the above-described condensation polymerization bath
transferred
with the esterified product, antimony trioxide was added by 0.03 part,
thereafter, steric
hindrance phenolic compound "IRGANOX1222" (registered trade mark) was added at
350
ppm relative to polymer, magnesium acetate solution was added by 70 ppm at a
weight of
magnesium atoms, phosphoric acid as a phosphoric compound was added by 10 ppm
at a
weight of phosphorus atoms, and thereafter, while agitating the low molecular
polymer at 30
rpm, the reaction system was gradually heated from 250 C to 285 C and the
pressure was
reduced down to 40 Pa. The times for reaching the final temperature and the
final pressure
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CA 02569001 2006-11-29
were both set at 60 minutes. At the time reaching a predetermined agitating
torque, the
reaction system was purged with nitrogen to return to a normal pressure and
the condensation
polymerization was stopped, the polymer was discharged into a cooled water and
immediately
cut to obtain columnar chips with a diameter of about 5 mm and a length of
about 7 mm (the
equivalent spherical diameter of the polymer was 6.4 mm). Where, the time from
start of
pressure reduction to reaching the predetermined agitating torque was 3 hours.
[0131] The intrinsic viscosity of the obtained polymer was 0.650 dl/g, the
concentration of
carboxylic end group was 25 equivqlent/106g polymer, and the amount of cyclic
trimer in the
polymer was 1.3% by weight.
[0132] The obtained polymer was dried at 150 C under a pressure-reduced
condition, and
then, the inside of the system was turned into a slightly pressurized
condition of 1.17 x 105 Pa
by nitrogen gas. The concentration of oxygen in the reaction system was 50 ppm
and the
moisture was 10 ppm. The system was kept at this pressure (staying condition),
and after
heat treatment was carried out at a temperature of 240 C for 9 hours, the
polymer was taken
out. The intrinsic viscosity of the obtained polymer was 0.645 dl/g, the
concentration of
carboxylic end group was 28 equivqlent/106g polymer, and the amount of cyclic
trimer in the
polymer was 0.40% by weight. The color tone of the polymer was good (polyester
composition (G)).
[0133] Example 9:
Polyethylene terephthalate was synthesized by condensation polymerization in a
manner similar to that in Example 8 other than a condition where "PEP45"
(registered trade
mark) was added by 300 ppm relative to polymer instead of adding
"IRGANOX1222", and
columnar chips with a diameter of about 5 mm and a length of about 7 mm were
obtained (the
equivalent spherical diameter of the polymer was 6.4 mm).
[0134] The intrinsic viscosity of the obtained polymer was 0.655 dl/g, the
concentration of
carboxylic end group was 28 equivqlent/106g polymer, and the amount of cyclic
trimer in the
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CA 02569001 2006-11-29
polymer was 1.3% by weight.
[0135] The obtained polymer was dried at 150 C under a pressure-reduced
condition, and
then, the inside of the system was turned into a slightly pressurized
condition of 1.17 x 105 Pa
by nitrogen gas. The concentration of oxygen in the system was 50 ppm and the
moisture
was 10 ppm. The system was kept at this pressure (staying condition), and
after heat
treatment was carried out at a temperature of 230 C for 9 hours, the polymer
was taken out.
The intrinsic viscosity of the obtained polymer was 0.625 dl/g, the
concentration of
carboxylic end group was 32 equivqlent/106g polymer, and the amount of cyclic
trimer in the
polymer was 0.45% by weight (polyester composition (H)).
[0136] Example 10:
Heat treatment was carried out in the same manner as that in Example 8 other
than a
condition where the moisture content in the system was changed to 0.5 ppm. The
amount of
cyclic trimer in the obtained polymer was 0.5% by weight (polyester
composition (I)).
[0137] Example 11:
The polymer with a concentration of cyclic trimer of 1.3% by weight
synthesized in
Example 8 was dried at 150 C under a pressure-reduced condition, and then, the
inside of the
system was turned into a slightly pressurized condition of 1.17 x 105 Pa by
nitrogen gas. The
concentration of oxygen in the reaction system was 15 ppm and the moisture was
1,500 ppm.
The system was kept at this pressure (staying condition), and after heat
treatment was carried
out at a temperature of 230 C for 9 hours, the polymer was taken out. Although
the amount
of cyclic trimer in the obtained polymer was 0.50% by weight, the intrinsic
viscosity of the
polymer was 0.530 dl/g, the concentration of carboxylic end group was 50
equivqlent/106g
polymer, and the polymer had a great reduction in viscosity and had a high
concentration of
carboxylic end group (polyester composition (J)).
[0138] Comparative Example 5:
Polyethylene terephthalate was synthesized by condensation polymerization in a
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CA 02569001 2006-11-29
manner similar to that in Example 8 other than a condition where "IRGANOX1222"
was not
added, and columnar chips with a diameter of about 5 mm and a length of about
7 mm were
obtained (the equivalent spherical diameter of the polymer was 6.4 mm).
[0139] The intrinsic viscosity of the obtained polymer was 0.665 dl/g, the
concentration of
carboxylic end group was 35 equivqlent/106g polymer, and the amount of cyclic
trimer in the
polymer was 1.3% by weight.
[0140] The obtained polymer was dried at 150 C under a pressure-reduced
condition, and
then, the inside of the system was turned into a slightly pressurized
condition of 1.17 x 105 Pa
by nitrogen gas. The concentration of oxygen in the system was 50 ppm and the
moisture
was 10 ppm. The system was kept at this pressure (staying condition), and
after heat
treatment was carried out at a temperature of 240 C for 9 hours, the polymer
was taken out.
The intrinsic viscosity of the obtained polymer was 0.645 dl/g, and the
concentration of
carboxylic end group was 38 equivqlent/106g polymer. Further, the amount of
cyclic trimer
in the polymer was 0.45% by weight (polyester composition (K)). In this
composition, the
polymer chips were colored.
[0141] Comparative Example 6:
Heat treatment was carried out in a manner similar to that in Example 8 other
than a
condition where, relatively to the melt polymerized polymer with a
concentration of cyclic
trimer of 1.3% by weight synthesized in Example 8, nitrogen gas was flowed at
a rate of 60
liters per 1 kg of polymer under a normal pressure condition. The amount of
cyclic trimer in
the obtained polymer was 0.40% by weight. Further, the intrinsic viscosity of
the polymer
increased up to 0.80 dl/g. The concentration of carboxylic end group was 20
equivqlent/106g
polymer (polyester composition (L)).
[0142] Comparative Examples 7 and 8:
Heat treatment was carried out in the same manner as that in Example 8 other
than a
condition where the temperature in the system was changed to 170 C
(Comparative Example
-42-
CA 02569001 2006-11-29
7) or 265 C (Comparative Example 8). In a case of 170 C, the amount of cyclic
trimer was
1.3% by weight, and it was not reduced at all. On the other hand, in a case of
265 C,
polymer adhered to the inner wall of the apparatus, the amount of cyclic
trimer was 1.2% by
weight, and the effect for reduction was not recognized (polyester composition
(M)
(Comparative Example 7), polyester composition (N) (Comparative Example 8)).
[0143] Example 12:
Polyester composition (G) obtained in Example 8 was dried under a pressure-
reduced
condition of 133 Pa at 180 C for 3 hours, supplied to an extruder for a main
layer (layer A),
melt extruded onto a casting drum, and rapidly cooled and solidified at a
condition brought
into contact with the casting drum having a surface temperature of 25 C while
applying static
electricity onto the casting drum, and a single layer film was prepared.
Successively, this
non-stretched film was stretched in the longitudinal direction by a roller-
type stretching
machine at 90 C at a draw ratio of 3.5 times, and further, stretched in the
transverse direction
by using a tenter at 105 C at a draw ratio of 3.5 times, and after heat
treatment under a
constant length condition at 200 C for ten seconds, relax treatment was
carried out by 2% in
the transverse direction, and thus, a single layer polyester film having a
thickness of 8 m was
obtained. The property for forming a film was good. When the film thus
obtained was
served to the forcible oligomer precipitation test, precipitated cyclic trimer
almost does not
exist and the color tone was good. The result is shown in Table 4.
[0144] Example 13:
Using two extruders, polyester composition (G) obtained in Example 8 was dried
under
a pressure-reduced condition of 133 Pa at 180 C for 3 hours, and supplied to
an extruder for a
main layer (layer A). Further, after polyester composition (H) obtained in
Example 9 was
dried under a pressure-reduced condition of 133 Pa at 180 C for 3 hours, it
was supplied to an
extruder for a sub layer (layer B) and was joined in a T-die, the polymer was
melt extruded
from a two-layer die onto a casting drum, it was rapidly cooled and solidified
at a condition
-43-
CA 02569001 2006-11-29
brought into contact with the casting drum having a surface temperature of 25
C while
applying static electricity onto the casting drum, and a two-layer non-
stretched film of A/B
type (thickness ratio: 6/1) was prepared. Successively, this non-stretched
film was stretched
in the longitudinal direction by a roller-type stretching machine at 90 C at a
draw ratio of 3.5
times, and further, stretched in the transverse direction by using a tenter at
105 C at a draw
ratio of 3.5 times, and after heat treatment under a constant length condition
at 200 C for ten
seconds, relax treatment was carried out by 2% in the transverse direction,
and thus, a
laminated polyester film having a thickness of 8 m was obtained (lamination
thickness of
layer B: 1.14 m). The property for forming a film was good. When the film thus
obtained
was served to the forcible oligomer precipitation test, precipitated cyclic
trimer almost does
not exist and the color tone was good. The result is shown in Table 4.
[0145] Comparative Example 9:
A single layer polyester film was obtained in the same manner as that in
Example 12
other than a condition where the polyester composition (K) obtained in
Comparative Example
was supplied instead of the polyester composition (G). The property for
forming a film
was good. When the film thus obtained was served to the forcible oligomer
precipitation
test, although precipitated cyclic trimer almost does not exist, the film was
colored. The
result is shown in Table 4.
[0146] Comparative Example 10:
A polyester composition was supplied to an extruder in the same manner as that
in
Example 12 other than a condition where the polyester composition (L) obtained
in
Comparative Example 6 was supplied instead of the polyester composition (G).
The
extrusion could not be carried out because of too high viscosity, and a film
could not be
formed.
[0147] Comparative Example 11:
A single layer polyester film was obtained in the same manner as that in
Example 12
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CA 02569001 2006-11-29
other than a condition where the polyester composition (L) obtained in
Comparative Example
6 was supplied instead of the polyester composition (G). The property for
forming a film
was good. When the film thus obtained was served to the forcible oligomer
precipitation
test, a large amount of cyclic trimer was precipitated. It is expected that it
cannot be fit for
use as film because many large protrusions exist. The result is shown in Table
4.
[0148] [Table 3]
-45-
Antioxidant Cyclic trimer Intrinsic Color tone Amount of
viscosity carboxylic end polyester
Name of Content Content in (dl/g) group composition
antioxidant (ppm) polymer (wt%) L a b (equivalent/ton)
Example 8 IRGANOX1222 350 0.40% 0.645 59.5 0.1 3.5 28 G
Example 9 PEP45 300 0.45% 0.625 60.1 -0.15 3 32 H
Example 10 IRGANOX1222 350 0.50% 0.66 60 0 3.3 26 I
~
Example 11 IRGANOX1222 350 0.50% 0.53 59 0.5 5 50 J
0
Comparative ~
Exam le 5 not added 0 0.45% 0.645 55 2 12 38 K 0
P
~
N
Comparative
rn Example 6 IRGANOX1222 350 0.40% 0.8 60.3 -0.1 2.5 20 L 0
,
Comparative IRGANOX1222 350 1.30% 0.65 61 0.1 3.3 25 M ~
Example 7 tD
Comparative IRGANOX1222 350 1.20% 0.63 58 1 4 40 N
Example 8
CA 02569001 2006-11-29
[0149] [Table 4]
Polymer composition Amount of
precipitation of
cyclic trimer Note
Layer A Layer B (number/mm2)
polyester
Example 12 0
composition G
Exam le 13 polyester polyester 0
p composition G composition H
Comparative polyester 0 film colored
Example 9 composition K
Comparative polyester cannot be cannot be formed as a
Example 10 composition L deter-nined film
Comparative polyester
200 Many large protrusions
Example 1 1 composition M
[0150] Next, the second polyester composition will be shown as follows.
(11) Determination of cyclic trimer in polyester:
1 g of polyester was dissolved in 20 ml of orthochlorophenol, and an internal
standard was
added. Further, the polymer was precipitated by adding methanol, supernatant
liquid was
sampled by centrifugal separation, and it was determined using liquid
chromatograph.
[0151 ](12) Determination of bis(hydroxyethyl)terephthalate in polyester:
0.5g of polyester was dissolved in 10 ml of hexafluoroisopropanol, and the
polymer was
precipitated by adding methanol. The polymer was separated by centrifugal
separation,
supernatant liquid was sampled, and the supernatant liquid was evaporated to
dryness. The
solid component evaporated to dryness was re-dissolved in 3 ml of DMSO, and an
amount of
BHT contained in the DMSO solution was determined using liquid chromatograph.
[0152] Absorbance of 365 nm ray:
0.8g of polyester was dissolved in 10 ml of orthochlorophenol. In a case where
particles and the like were contained in polyester, the particles were settled
by centrifugal
separation of the solution, and its supernatant liquid was served to the
determination. Using
orthochlorophenol as reference and using a spectrophotometer U3010 produced by
Hitachi
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CA 02569001 2006-11-29
Co., Ltd., the absorbance at 365 nm was determined.
[0153] (14) Forcible oligomer precipitation test:
After a film having a square shape with vertical and transverse sizes of 5 cm
was heated
in a hot air oven at 150 C for 30 minutes, the film surface was observed by a
scanning
electron microscope, and the number of precipitated cyclic trimer having a
diameter of not
less than 1 m per 100 m square was counted.
[0154] Example 14:
100 parts by weight of terephthalic dimethyl and 62 parts by weight of
ethylene glycol
were deposited into a transesterification bath and molten at 150 C. Then, 0.05
part by
weight of magnesium acetate tetrahydrate was deposited thereinto, and while
methanol was
distilled, the transesterification was carried out. The temperature of the
reacted material was
elevated up to 235 C for 3 hours, and after the transesterification was
completed, 0.01 part by
weight of orthophosphoric acid was added. Further, 0.1 part by weight of
colloidal silica
having a mean diameter of 0.3 m was added, and then, 0.015 part by weight of
antimony
trioxide was added. Thereafter, the reacted material was transferred to a
condensation
polymerization bath.
[0155] While agitating the low molecular polymer at 30 rpm, the reaction
system was
gradually heated from 235 C to 285 C and the pressure was reduced down to 130
Pa. The
times for reaching the final temperature and the final pressure were both set
at 90 minutes.
At the time reaching a predetermined agitating torque, the reaction system was
returned to a
normal pressure by nitrogen gas and the condensation polymerization was
stopped, the
polymer was discharged into a cooled water in a strand-like form and
immediately cut to
obtain polyester chips. The intrinsic viscosity of the obtained polyester
chips was 0.63, and
the content of cyclic trimer was 1.2% by weight.
[0156] This polyester was dried at 170 C under a pressure-reduced condition to
prepare
polyester having a degree of crystallization of 60%. The apparent volume per 1
kg chips was
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CA 02569001 2006-11-29
1.43 liters.
[0157] Then, 100 parts by weight of chips finished with drying were charged
into a rotary-
type heat treatment machine whose capacity of the inside of the bath was 300%
of the
apparent volume of the chips, the inside was filled with nitrogen gas having a
moisture rate of
not higher than 40 ppm and an oxygen concentration of not higher than 40 ppm,
and the
pressure of the inside was controlled at 930 hPa. Then, the temperature of the
inside of the
bath was elevated, and from the time reaching 230 C, the temperature was kept
for 20 hours,
and thereafter, the chips were taken out. The intrinsic viscosity of the
obtained chips was
0.64, the amount of cyclic trimer was 0.32% by weight, and the degree of
crystallization was
75%. The other properties are shown in Tables 5 and 6.
[0158] The chips finished in treatment were deposited into an extruder, molten
at 285 C,
and extruded from a die in a form of a sheet. The molten sheet was cooled by
bringing it into
contact with a mirror-surface drum, whose surface temperature was controlled
at 25 C, by
electrostatic application method. Then, the obtained amorphous polyester sheet
was
stretched in the longitudinal direction at a draw ratio of 3.3 times by
stretching rollers heated
at 90 C, and thereafter, stretched in the transverse direction at a
temperature of 110 C and a
draw ratio of 3.8 times by a tenter-type stretching machine. The film
completed in stretching
was wound in a form of a roll after being heat set at 230 C. The property for
forming a film
was good. The thickness of the film was 30 m, and the content of cyclic trimer
contained in
the film was 0.49% by weight. When the forcible oligomer precipitation test
was carried
out, precipitation of oligomer was not observed. The properties are shown in
Table 7.
[0159] Examples 15 and 16:
Films were formed in a manner similar to that in Example 14 other than
conditions
where the times for heat treatment were changed to 10 hours and 6 hours,
respectively.
[0160] Examples 17 and 18:
In Example 14, only the content of orthophosphoric acid was changed,
polymerization
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CA 02569001 2006-11-29
was carried out similarly, and after heat treatment, films were formed.
[01611 Example 19:
A film was formed in a manner similar to that in Example 14 other than a
condition
where the torque for determining the completion of polymerization was changed.
Because
the intrinsic viscosity of the polymer was low, it was difficult to control
the thickness of the
extruded sheet uniformly, and film breakage during film formation also
occurred.
[0162] Example 20:
Polyester chips were obtained in a manner similar to that in Example 14 other
than a
condition where the raw material of 100 parts by weight of terephthalic
dimethyl in Example
14 was changed to 94 parts by weight of terephthalic dimethyl and 6 parts by
weight of
isophthalic dimethyl. The intrinsic viscosity of the obtained polyester chips
was 0.65, and
the content of cyclic trimer was 1.0% by weight.
[0163] This polyester was dried at 170 C under a pressure-reduced condition to
prepare
polyester having a degree of crystallization of 30%. The apparent volume per 1
kg chips was
1.43 liters.
[0164] Then, 100 parts by weight of chips finished in drying were charged into
a rotary-type
heat treatment machine whose capacity of the inside of the bath was 300% of
the apparent
volume of the chips, the inside was filled with nitrogen gas having a moisture
rate of not
higher than 40 ppm and an oxygen concentration of not higher than 40 ppm, and
the pressure
of the inside was controlled at 930 hPa. Then, the temperature of the inside
of the bath was
elevated, and from the time reaching 230 C, the temperature was kept for 20
hours, and
thereafter, the chips were taken out. The intrinsic viscosity of the obtained
chips was 0.65,
the amount of cyclic trimer was 0.45% by weight, and the degree of
crystallization was 60%.
The other properties are shown in Tables 5 and 6.
[0165] The chips finished in treatment were deposited into an extruder, molten
at 285 C,
and extruded from a die in a form of a sheet. The molten sheet was cooled by
bringing it into
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CA 02569001 2006-11-29
contact with a mirror-surface drum, whose surface temperature was controlled
at 25 C, by
electrostatic application method. Then, the obtained amorphous polyester sheet
was
stretched in the longitudinal direction at a draw ratio of 3.3 times by
stretching rollers heated
at 90 C, and thereafter, stretched in the transverse direction at a
temperature of 110 C and a
draw ratio of 3.8 times by a tenter-type stretching machine. The film
completed in stretching
was wound in a form of a roll after being heat set at 230 C. The thickness of
the film was
30 m, and the content of cyclic trimer contained in the film was 0.65% by
weight. The
result is shown in Table 7.
[0166] Example2l:
Polyester chips were obtained in a manner similar to that in Example 14 other
than a
condition where the agitating torque for determining the completion of melt
polymerization
was set low. The intrinsic viscosity of the polyester chips was 0.60, and the
content of cyclic
trimer was 1.0% by weight.
[0167] This polyester was dried at 170 C under a pressure-reduced condition to
prepare
polyester having a degree of crystallization of 60%. The apparent volume per 1
kg chips was
1.43 liters.
[0168] Then, 100 parts by weight of chips finished in drying were charged into
a rotary-type
heat treatment machine whose capacity of the inside of the bath was 300% of
the apparent
volume of the chips, the inside was filled with nitrogen gas having a moisture
rate of not
higher than 40 ppm and an oxygen concentration of not higher than 40 ppm, and
the pressure
of the inside was controlled at 650 hPa. Then, the temperature of the inside
of the bath was
elevated, and from the time reaching 230 C, the temperature was kept for 20
hours, and
thereafter, the chips were taken out. The intrinsic viscosity of the obtained
chips was 0.63,
the amount of cyclic trimer was 0.32% by weight, and the degree of
crystallization was 75%.
The content of bis(hydroxyethyl)terephthalate was 40 ppm. The other properties
are shown
in Tables 5 and 6.
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CA 02569001 2006-11-29
[0169] The chips finished in treatment were deposited into an extruder, molten
at 285 C,
and extruded from a die in a form of a sheet. The molten sheet was cooled by
bringing it into
contact with a mirror-surface drum, whose surface temperature was controlled
at 25 C, by
electrostatic application method. Then, the obtained amorphous polyester sheet
was
stretched in the longitudinal direction at a draw ratio of 3.3 times by
stretching rollers heated
at 90 C, and thereafter, stretched in the transverse direction at a
temperature of 110 C and a
draw ratio of 3.8 times by a tenter-type stretching machine. The film
completed in stretching
was wound in a form of a roll after being heat set at 230 C. The thickness of
the film was 30
m, and the content of cyclic trimer contained in the film was 0.49% by weight.
When the
forcible oligomer precipitation test was carried out, precipitation of
oligomer was not
observed. The result is shown in Table 7.
[0170] Example 22:
Polyester was polymerized in a manner similar to that in Example 14 other than
a
condition where the content of antimony trioxide in Example 14 was changed to
0.02 part by
weight, and further, drying and heat treatment of the chips and film formation
were carried
out. Because the amount of antimony element was much, cyclic trimer was
regenerated
during film formation, and the amount of cyclic trimer in the film increased.
[0171] Example 23:
100 parts by weight of terephthalic dimethyl and 62 parts by weight of
ethylene glycol
were deposited into a transesterification bath and molten at 150 C. Then, 0.05
part by
weight of magnesium acetate tetrahydrate was deposited thereinto, and while
methanol was
distilled, the transesterification was carried out. The temperature of the
reacted material was
elevated up to 235 C for 3 hours, and after the transesterification was
completed, 0.01 part by
weight of orthophosphoric acid was added. Further, 0.1 part by weight of
colloidal silica
having a mean diameter of 0.3 m was added, and then, titanium lactate sodium
chelate
compound prepared Reference Example was added so that titanium element was 5
ppm
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CA 02569001 2006-11-29
(weight) relative to terephthalic dimethyl. Thereafter, the reacted material
was transferred
to a condensation polymerization apparatus.
[0172] While agitating the low molecular polymer at 30 rpm, the reaction
system was
gradually heated from 235 C to 285 C and the pressure was reduced down to 130
Pa. The
times for reaching the final temperature and the final pressure were both set
at 90 minutes.
At the time reaching a predetermined agitating torque, the reaction system was
returned to a
normal pressure by nitrogen gas and the condensation polymerization was
stopped, the
polymer was discharged into a cooled water in a strand-like form and
immediately cut to
obtain polyester chips. The intrinsic viscosity of the obtained polyester
chips was 0.64, and
the content of cyclic trimer was 1.2% by weight.
[0173] This polyester was dried at 170 C under a pressure-reduced condition to
prepare
polyester having a degree of crystallization of 60%. The apparent volume per 1
kg chips was
1.43 liters.
[0174] Then, 100 parts by weight of chips finished in drying were charged into
a rotary-type
heat treatment machine whose capacity of the inside of the bath was 300% of
the apparent
volume of the chips, the inside was filled with nitrogen gas having a moisture
rate of not
higher than 40 ppm and an oxygen concentration of not higher than 40 ppm, and
the pressure
of the inside was controlled at 930 hPa. Then, the temperature of the inside
of the bath was
elevated, and from the time reaching 230 C, the temperature was kept for 20
hours, and
thereafter, the chips were taken out. The intrinsic viscosity of the obtained
chips was 0.64,
the amount of cyclic trimer was 0.36% by weight, and the degree of
crystallization was 70%.
The other properties are shown in Tables 5 and 6.
[0175] The chips finished in treatment were deposited into an extruder, molten
at 285 C,
and extruded from a die in a form of a sheet. The molten sheet was cooled by
bringing it into
contact with a mirror-surface drum, whose surface temperature was controlled
at 25 C, by
electrostatic application method. Then, the obtained amorphous polyester sheet
was
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CA 02569001 2006-11-29
stretched in the longitudinal direction at a draw ratio of 3.3 times by
stretching rollers heated
at 90 C, and thereafter, stretched in the transverse direction at a
temperature of 110 C and a
draw ratio of 3.8 times by a tenter-type stretching machine. The film
completed in stretching
was wound in a form of a roll after being heat set at 230 C. The thickness of
the film was
30 m, and the content of cyclic trimer contained in the film was 0.50% by
weight. When the
forcible oligomer precipitation test was carried out, precipitation of
oligomer was not
observed. The properties are shown in Table 7.
[0176] Example 24:
Melt polymerization was carried out similarly in Example 14, and the condition
of cutting
was changed to change the shape of chips. The intrinsic viscosity of the
obtained polyester was
0.64, and the content of cyclic trimer was 1.2% by weight. This polyester was
dried at 170 C
under a pressure-reduced condition to prepare polyester having a degree of
crystallization of
60%. The apparent volume per 1 kg chips was 1.0 liter.
[0177] Then, a film was formed, carrying out heat treatment at a condition
similar to that in
Example 14. Because the bulk specific gravity of chips was 1.0, coloring was
observed by
heat treatment.
[0178] Examples 25 to 27:
Polyester chips were obtained in a manner similar to that in Example 14 other
than
conditions where the agitating torques for determining the completion of melt
polymerization
were set high, and after carrying out heat treatment similarly to in Example
14, films were
obtained.
[0179] Example 28:
Heat treatment was carried out in a manner similar to that in Example 14 other
than a
condition where the ratio between the capacity of the inside of the heat
treatment machine in
Example 14 and the apparent volume of the chips was changed from 300% to 200%,
and a film
was formed.
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CA 02569001 2006-11-29
[0180] Example 29:
Heat treatment was carried out in a manner similar to that in Example 14 other
than a
condition where the ratio between the capacity of the inside of the heat
treatment machine in
Example 14 and the apparent volume of the chips was changed from 300% to 120%,
and a film
was formed.
[0181] Example 30:
A film was formed in a manner similar to that in Example 14 other than a
condition
where the heat treatment condition in Example 14 was changed to an atmosphere
pressure of
0.3 MPa and a nitrogen flowing amount of 2 liters/hr. per 1 kg polyester.
Scratches were
slightly observed in the obtained film.
[0182] Example 31:
Heat treatment was carried out in a manner similar to that in Example 30 other
than a
condition where the nitrogen flowing amount in Example 30 was changed to 1
liter/hr., and a
film was formed.
[0183] Example 32:
Heat treatment was carried out in a manner similar to that in Example 30 other
than a
condition where the atmosphere pressure in Example 30 was changed to 0.1 MPa,
and a film
was formed. Scratches were slightly observed in the obtained film.
[0184] Example 33:
A two-layer lamination film forming machine having two extruders was prepared.
Each of chips heat treated in Example 14 and chips only dried without carrying
out heat
treatment were supplied to each of the respective two extruders, and they were
melt extruded,
respectively. The molten polymers were laminated in a lamination block in a
two-layer
form, and it was extruded from a die in a form of a sheet. At that time, the
non-heat treated
polymer was laminated on the side of a mirror-surface cooling drum, and the
heat treated
polymer was laminated on the non-drum side. The ratio of lamination was set at
heat treated
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CA 02569001 2006-11-29
polymer/non-heat treated polymer=1:5. The obtained amorphous laminated
polyester sheet
was stretched and heat treated in the same conditions as those in Example 14.
[0185] Example 34:
The non-heat treated chips in Example 14 were used. The polyester chips were
dried
at 170 C under a pressure-reduced condition to prepare polyester chips having
a degree of
crystallization of 60%. The apparent volume per 1 kg polyester chips was 1.43
liters.
[0186] Then, 100 parts by weight of polyester chips finished in drying were
charged into a
rotary-type heat treatment machine whose capacity of the inside of the bath
was 300% of the
apparent volume of the chips, the inside was filled with nitrogen gas having a
moisture rate of
not higher than 40 ppm and an oxygen concentration of not higher than 40 ppm,
and the
pressure of the inside of the bath was controlled at an atmospheric pressure.
Then, the
temperature of the inside of the bath was elevated under a condition where
nitrogen gas was
not flowed, and from the time reaching 230 C, heat treatment was carried out
for 30 minutes
(Process A).
[0187] When the time of 30 minutes passed, the inside of the bath was reduced
in pressure,
and when the pressure became 130 Pa or lower, nitrogen gas was flowed again in
the bath and
the inside of the bath was turned to an atmospheric pressure. The time from
starting to
reduce the pressure in the bath to again filling the bath with nitrogen gas
was 5 minutes
(Process B).
[0188] Further, 30 minutes of heat treatment and 5 minutes of replacing the
gas in the bath
were repeated alternately, and totally heat treatment of 19 hours and 50
minutes was carried
out.
[0189] The intrinsic viscosity of the obtained chips was 0.65, the amount of
cyclic trimer
was 0.32% by weight, and the degree of crystallization was 75%. The other
properties are
shown in Tables 8 and 9.
[0190] The chips finished in treatment were formed to a film at the same
conditions as those
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CA 02569001 2006-11-29
in Example 14. The result is shown in Table 10.
[0191] Example 35:
A film was formed in the same manner as that in Example 34 other than
conditions
where the treatment time of Process A in Example 34 was set at 30 minutes, the
time of
Process B was changed to 15 minutes, the final process was set to be Process
A, and the
polyester was heat treated totally for 20 hours. The result is shown in Tables
8 to 10.
[0192] Example 36:
A polyester film was formed in the same manner as that in Example 34 other
than
conditions where the treatment time of Process A in Example 34 was changed to
2 hours, the
time of Process B was set at 5 minutes, the time of the final Process A was
set at 75 minutes,
and the polyester was heat treated totally for 20 hours. The result is shown
in Tables 8 to 10.
[0193] Example 37:
A polyester film was formed in the same manner as that in Example 34 other
than
conditions where the treatment time of Process A in Example 34 was changed to
10 hours, and
the polyester was heat treated totally for 20 hours and 5 minutes. The result
is shown in
Tables 8 to 10.
[0194] Comparative Example 12:
A film was obtained formed in the same manner as that in Example 14 other than
a
condition where the heat treatment was not carried out. The amount of cyclic
trimer in the
film was 1.2% by weight, and the number of oligomer precipitation was 50/100 m
~.
[0195] Comparative Example 13:
The polyester chips polymerized in Example 14 were dried at 170 C under a
pressure-
reduced condition to prepare polyester having a degree of crystallization of
60%. The
apparent volume per 1 kg chips was 1.43 liters. Then, 100 parts by weight of
chips finished
in drying were charged into a rotary-type heat treatment machine whose
capacity of the inside
of the bath was 300% of the apparent volume of the chips, and the pressure of
the inside was
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CA 02569001 2006-11-29
controlled at 100 Pa. Then, the temperature of the inside of the bath was
elevated, and from
the time reaching 230 C, the temperature was kept for 20 hours, and
thereafter, the chips were
taken out. The intrinsic viscosity of the obtained chips was 1.0, the amount
of cyclic trimer
was 0.35% by weight, and the degree of crystallization was 75%. The other
properties are
shown in Tables 8 and 9.
[0196] The chips finished in treatment were deposited into an extruder, molten
at 285 C,
and extruded from a die in a form of a sheet. At that time, because the
intrinsic viscosity of
the chips was high, the exothermic amount due to shear in the extruder was
great, and the
temperature of the molten polymer was higher than 300 C. The molten sheet was
cooled by
bringing it into contact with a mirror-surface drum, whose surface temperature
was controlled
at 259C, by electrostatic application method. Then, although the film was
formed at
conditions similar to those in Example 14, the property for forming a film was
poor, and film
breakage occurred frequently. Therefore, the film obtained was corresponding
to about 20%
(weight ratio) of the polymer used. Further, because the amount of carboxylic
end group of
the polyester chips served to the film formation was little, the contact
property with rollers
was not sufficient, and scratches were sometimes observed on the film surface.
The content
of cyclic trimer contained in the film was 0.75% by weight. The properties are
shown in
Table 10.
[0197] Comparative Example 14:
A film was obtained in a manner similar to that in Example 14 other than
conditions
where the pressure of nitrogen gas in the heat treatment was controlled at
0.15 MPa and the
flowing amount thereof was set at 0.5 liter/hr. per 1 kg polyester. The
polyester finished in
heat treatment was colored, and the color tone of the film was also yellowish.
[0198] Comparative Example 15:
A film was obtained in a manner similar to that in Example 14 other than a
condition
where the temperature of the heat treatment was changed to 180 C. The amount
of cyclic
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CA 02569001 2006-11-29
trimer was not reduced at all.
[0199] Comparative Example 16:
A film was obtained in a manner similar to that in Example 14 other than a
condition
where the temperature of the heat treatment was changed to 255 C. The chips
were fused to
each other in the heat treatment machine and became an aggregate-like
condition. Further,
the chips were colored to be brown. Because the chips became an aggregate-like
condition,
film formation could not be carried out.
[0200] Comparative Example 17:
Chips were obtained in a manner similar to that in Example 14 other than a
condition
where the torque for determining the completion of melt polymerization was set
small, and
after heat treatment carried out in a manner similar to that in Example 14, a
film was formed.
However, because the intrinsic viscosity was too low, the width of the
extruded sheet was not
stable, and further, because the extruded sheet was fragile, film formation
could not be carried
out.
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CA 02569001 2006-11-29
[0201] [Table 5]
Polymer properties before heat treatment
Amount of
Intrinsic viscosity Amount of cyclic carboxylic end
trimer (wt%) group
(equivalent/ton)
Example 14 0.63 1.2 20
Example 15 0.63 1.2 20
Example 16 0.63 1.2 20
Example 17 0.64 1.2 30
Example 18 0.64 1.2 35
Example 19 0.57 1.0 18
Example 20 0.65 1.0 22
Example 21 0.60 1.0 16
Example 22 0.63 1.2 25
Example 23 0.64 1.2 22
Example 24 0.64 1.2 20
Example 25 0.70 1.2 30
Example 26 0.75 1.2 32
Example 27 0.80 1.2 33
Example 28 0.63 1.2 20
[0202] [Table 6]
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Polymer properties after heat treatment
Amount of cyclic Amount of Degree of Catalyst for
carboxylic end Absorbance at Amount of
Intrinsic viscosity trimer crystallization polymerization
(~a~o) group 365nm BHT(ppm)
(%) /Content (ppm)
e uivalent/ton
Example 14 0.64 0.32 20 0.24 110 75 Sb/120
Example 15 0.64 0.42 20 0.23 120 75 Sb/120
Example 16 0.64 0.58 20 0.23 120 75 Sb/120
Example 17 0.63 0.30 32 0.28 130 75 Sb/120
Example 18 0.62 0.30 38 0.29 130 75 Sb/120
Example 19 0.56 0.28 19 0.23 160 80 Sb/120 N
Ln
Example 20 0.65 0.45 24 0.26 150 60 Sb/120 0
0
, Example 21 0.63 0.32 17 0.22 40 75 Sb/120
0
Example 22 0.64 0.30 28 0.25 120 75 Sb/165 0
0)
~
Example 23 0.64 0.36 25 0.30 115 70 Ti/5 N
tD
Example 24 0.63 0.35 30 0.35 120 75 Sb/120
Example 25 0.70 0.45 35 0.32 100 65 Sb/120
Example 26 0.75 0.45 33 0.32 100 65 Sb/120
Example 27 0.80 0.45 35 0.33 100 65 Sb/120
Example 28 0.63 0.32 25 0.27 110 75 Sb/120
Note) In the Table, BHT represents bis (hydroxyethyl) terephthalate.
CA 02569001 2006-11-29
[0203] [Table 7]
Film properties
Amount of cyclic trimer Amount of precipitation of
(wt%) oligomer (number/100 m~)
Example 14 0.49 0
Example 15 0.59 12
Example 16 0.68 20
Example 17 0.51 0
Example 18 0.53 0
Example 19 0.45 0
Example 20 0.65 15
Example 21 0.49 0
Example 22 0.60 12
Example 23 0.50 0
Example 24 0.50 0
Example 25 0.63 10
Example 26 0.65 17
Example 27 0.68 20
Example 28 0.49 0
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CA 02569001 2006-11-29
[0204] [Table 8]
Polymer properties before heat treatment
Amount of cyclic Amount of carboxylic
Intrinsic viscosity trimer end group
(wt%) (equivalent/ton)
Example 29 0.63 1.2 20
Example 30 0.63 1.2 20
Example 31 0.63 1.2 20
Example 32 0.63 1.2 20
Example 33 0.63 1.2 20
Example 34 0.63 1.2 20
Example 35 0.63 1.2 20
Example 36 0.63 1.2 20
Example 37 0.63 1.2 20
Comparative
Example 12 0.63 1.2 20
Comparative
Example 13 0.63 1.2 20
Comparative
Example 14 0.63 1.2 20
Comparative
Example 15 0.63 1.2 20
Comparative 0.63 1.2 20
Example 16
Comparative
Example 17 0.50 1.0 18
[0205] [Table 9]
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Polymer properties after heat treatment
Amount of cyclic Amount of Degree of Catalyst for
carboxylic end Absorbance at Amount of BHT Intrinsic viscosity trimer
crystallization polymerization
(wt%) (equi~ lentlton) 365nm (ppm) (%) /Content (ppm)
Example 29 0.63 0.33 28 0.31 110 75 Sb/120
Example 30 0.65 0.32 15 0.28 90 75 Sb/120
Example 31 0.64 0.33 18 0.30 105 75 Sb/120
Example 32 0.68 0.30 15 0.27 110 75 Sb/120
Example 33 0.64 0.32 20 0.24 110 75 Sb/120
Example 34 0.65 0.32 20 0.23 130 75 Sb/120 ~
Example 35 0.66 0.32 18 0.22 50 75 Sb/120 0 u,
Example 36 0.63 0.32 20 0.25 100 75 Sb/120 ~
0
0
Example 37 0.62 0.33 35 0.29 130 75 Sb/120 ~
i N
Comparative - - - - - - Sb/120 0 0
Example 12 O1
Comparative ~
Exam le 13 1.0 0.35 5 0.23 20 75 Sb/120 N
P tD
Comparative 0.60 0.33 40 0.38 100 75 Sb/120
Example 14
Comparative 0.63 1.2 20 0.24 115 50 Sb/120
Example 15
Comparative 0.58 1.1 60 0.40 150 80 Sb/120
Example 16
Comparative 0.51 0.28 18 0.23 150 80 Sb/120
Example 17
Note) In the Table, BHT represents bis (hydroxyethyl) terephthalate.
CA 02569001 2006-11-29
[0206] [Table 10]
Film properties
Amount of cyclic trimer Amount of precipitation of
(wt%) oligomer (number/100gm0)
Example 29 0.49 0
Example 30 0.52 5
Example 31 0.50 0
Example 32 0.50 0
non-drum surface: 0
Example 33 1.1 drum surface: 25
Example 34 0.50 0
Example 35 0.50 0
Example 36 0.49 0
Example 37 0.50 0
Comparative 1.2 50
Example 12
Comparative 0.75 30
Example 13
Comparative 0.50 2
Example 14
Comparative 1.2 48
Example 15
Comparative - -
Example 16
Comparative
Example 17
Industrial Applications of the Invention
[0207] The polyester resin composition according to the present invention can
be effectively
used for a formed body such as a fiber, a film or a bottle. Further, the
polyester film
according to the present invention is effective, particularly, for use as
magnetic tapes, optical
films, containers for foods, and for lamination with steel plate or wrapping,
or as electric
insulation films.
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