Note: Descriptions are shown in the official language in which they were submitted.
CA 02678195 2009-09-08
Fast Heat-up Thermoplastic Polymer Composition
and Preparation Thereof
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is generally related to theremoplastic
polymer composition, and more particularly to thermoplastic polymer
composition and preparation thereof wherein the thermoplastic
polymer composition can be employed to fabricate almost achromatic
bottle and the bottle preform made of mentioned thermoplastic polymer
composition can be fast heat-up before blowing.
2. Description of the Prior Art
Thermoplastic polymer, especially polyethylene terephthalate
(PET) or PET co-polymer, is well known to be used on fabricating films,
bottles, or other containers for food or drink. Generally, bottle
manufacturing comprises two stages. Taking PET bottle
manufacturing as example, the first stage is injecting PET into a mold
for forming bottle preform, and the second stage is injecting
compressed air into the mold for blowing the bottle preform to bottle.
In the second stage, the bottle preform should be heated to about 100
C for blowing, so that the reheating rate becomes the rate-determining
step of the second stage. Commercially, quartz tube is used for the
mentioned reheating, and the wave-length of electro-magnetic wave
from the quartz tube is mostly between 500 nm to 2000 nm.
However, the absorption of electro-magnetic wave for PET is not
good in the mentioned wave-length range. Mostly, the
electro-magnetic wave during reheating is absorbed by impurities or
additives in bottle preform, such as catalyst residues or other
impurities. It means that the bottle preform can majorly absorb the
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electro-magnetic wave from the quartz tube by the impurities or
additives. Therefore, reheating time is highly related to the
composition of the bottle perform. When PET composition includes
more impurities or additives, the reheating rate becomes faster, and the
haze of the bottle preform is increased. Moreover, if the color of the
additives is deeper, the electro-magnetic wave absorbing ability of the
bottle preform is better, and the reheating time of the bottle preform is
shorter. Cause of employing additives with deep color in the bottle
preform, the produced bottle will not be transparent and achromatic.
The mentioned bottle cannot be satisfied in the recently commercial
requirement, especially for Asia marketing requirement, on achromatic
bottle or other containers.
There are many patents disclosed how to increase
electromagnetic radiation absorption and decrease reheating time by
employing additives in thermoplastic polymer composition. For
instance, in US Pat. 4408004, carbon black is employed as additives for
decreasing reheating time. Some iron oxide also can approach the
mentioned purpose, such as Fe2O3 disclosed in US Pat. 4420581. In
US Pat. 5419936, reducing antimony trioxide into antimony metal is
used to increase reheating rate. Some anthraquinone based dyes are
mentioned in US Pat. 4481314 for the mentioned purpose. In US Pat.
6660792, some iron compounds that will not participate in the reaction,
such as FeP, FeSi, or their combination, are used to decrease reheating
time. US Pat. 7189777 disclosed that activated carbon is employed for
increasing reheating rate. All the mentioned additives are blackbody
or graybody absorption, and the additives will absorb full spectrum
wave. The blackbody absorption or graybody absorption of the
additives will cause that the product formed thereof, such as bottles or
other type container, becomes un-acceptable on the product color and
haze. The more the additives is added, the more un-acceptable
influence is caused. In some cases, the mentioned influence can be
decreased by modifying the particle size of the additives. But, the
mentioned cannot be completely avoided by modifying particle size.
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Besides, US Pat. 5529744 disc; osed a bottle made of
thermoplastic polymer including metal particles, such as Sb, Sri, Ag,
Au, Cu, As, Cd, Hg, Pt, and/or Pd. In this mentioned patent, reducing
agent and the compounds with the mentioned metals are added in
polymerized process, and the metal compounds are reduced into metal
particles, especially Sb, to increase the reheating rate of the polymers.
But, according to this US patent, the absolute yellowness of the bottle
or other type container produced from the polymer is too large to obtain
achromatic product.
Though all the mentioned additives can increase reheating time
of bottle preform, save energy, and improve manufacturing
performance, the commercial requirement of achromatic containers
still cannot be satisfied through those mentioned additives. Therefore,
it is important to provide a thermoplastic polymer composition that can
not only be fast heat-up during manufacturing but also produce almost
achromatic product.
SUMMARY OF THE INVENTION
According to the above, the present invention provides new
thermoplastic polymer composition and preparation thereof to fulfill the
requirements of this industry.
One object of the present invention is to add conductive material
in proper amount into thermoplastic polymer composition to increase
the thermo-conduction thereof, so that the heating rate of the preform
will be improved.
Another object of the present invention is to employ
thermo-plastic polymer composition with well-dispersed metal particles
in proper amount, thus the preform made of the thermo-plastic
polymer composition is fast heat-up and the product made of the
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preform is almost achromatic.
Still another object of the present invention is provide a fast
heat-up thermoplastic polymer composition, the mentioned fast
heat-up thermoplastic polymer composition comprises thermoplastic
polymer and a plurality of metal particles, wherein the number
average molecular weight (Mn) of the thermoplastic polymer is between
1,000 to 60,000, and the metal particle is selected from aluminum (Al),
magnesium (Mg), zinc (Zn), tungsten (W), calcium (Ca), or the
composition thereof. Upon the manufacturing necessary, mentioned
fast heat-up thermoplastic polymer composition according to this
invention can be made as melt, pellet, sheet, or container, especially
properly for bottle preform and bottle.
Still another object of the present invention is provide a method
of manufacturing fast heat-up thermoplastic polymer composition, the
mentioned method comprises the following procedure: adding metal
particles into thermoplastic polymer during one stage selected from the
following: slurry stage, esterfication stage, melt state polycondensation
stage, any other post-polymerization melt process, or forming stage
According to above-mentioned objectives, the fast heat-up
thermo-plastic polymer composition of present invention comprises
thermo-conductive metal particles, so that the heating rate can be
efficiently increased, and the reheating time before processing, such as
blowing, can be reduced. Besides, because the selection of the metal
particles have been thought about the final coloring and transparency
of the metal particle dispersion in the thermoplastic polymer, the
product, such as bottle, made of the thermoplastic polymer
composition can be fabricated in almost achromatic through properly
controlling the adding amount and the particle size of the metal
particles. Therefore, the thermoplastic polymer composition and
preparation thereof according to this invention can achieve the
requirement of markets, especially for Asia.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
What is probed into the invention is fast heat-up thermoplastic
polymer composition and preparation thereof. Detail descriptions of
the structure and elements will be provided in the following in order to
make the invention thoroughly understood. Obviously, the
application of the invention is not confined to specific details familiar to
those who are skilled in the art. On the other hand, the common
structures and elements that are known to everyone are not described
in details to avoid unnecessary limits of the invention. Some preferred
embodiments of the present invention will now be described in greater
detail in the following. However, it should be recognized that the
present invention can be practiced in a wide range of other
embodiments besides those explicitly described, that is, this invention
can also be applied extensively to other embodiments, and the scope of
the present invention is expressly not limited except as specified in the
accompanying claims.
One preferred embodiment of this present invention discloses a
fast heat-up thermoplastic polymer composition. The mentioned fast
heat-up thermoplastic polymer composition comprises a thermoplastic
polymer, and metal particles. In one example of this embodiment, the
thermoplastic polymer is polyester composed of a repeat unit A of
di-acid based derivatives and a repeat unit B of diol based derivatives.
The mentioned di-acid based derivatives comprises C2-C16 aliphatic
di-carboxylic acid, Cs-C16 aromatic di-carboxylic acid, or the
composition thereof. Selectively, the di-acid derivatives comprises at
least one C8-C16 aromatic di-carboxylic acid. Preferably, the C8-C16
aromatic di-carboxylic acid is terephthalic acid. In one preferred
example, the thermoplastic polymer is polyethylene terephthalate (PET),
or co-polyester with polyethylene terephthalate. When counting as the
total mole of the di-acid based derivatives, terephthalic acid is at least
60 mol% of the di-acid based derivatives. When counting as the total
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mole of the diol based derivatives, ethylene glycol is at least 60 mol% of
the diol based derivatives.
Selectively, in another example of this embodiment, the
mentioned di-acid based derivatives comprises two C8-C16 aromatic
di-carboxylic acids. These two C8~Ci6 aromatic di-carboxylic acids
separately are terephthalic acid and isophthalic acid. Preferably, the
di-acid based derivatives comprises 96-99 mol% terephthalic acid, and
4-1 mol% isophthalic acid.
Selectively, in another example of this embodiment, the
mentioned diol based derivatives comprises at least one C2-Cio diol.
Preferably, the mentioned diol based derivatives comprises at least one
C2-C5 diol. In another example of this embodiment, the diol based
derivatives comprises ethylene glycol. During the polymerization, part
of ethylene glycol will be dehydrating and di-ethylene glycol (DEG) is
formed thereof, so that the repeat unit B derived from di-ethylene glycol
will exist in the co-polyester of the polymer product. Preferably, in the
polyester product, when counting as the total mole of the repeat unit B,
the repeat unit derived from ethylene glycol is 95-99 mol%, and the
repeat unit derived from di-ethylene glycol is 5-1 mol%.
According to this embodiment, the metal particle is selected from
aluminum (AI), magnesium (Mg), zinc (Zn), tungsten (W), calcium (Ca),
or the composition thereof. In one preferred example, the metal
particles are Al particles. Preferably, in the thermoplastic polymer
composition of this embodiment, when counting as the total weight of
the thermoplastic polymer, the metal particles are from 1 PPM to 200
PPM. More preferably, the metal particles are from 1 PPM to 100 PPM
of the thermoplastic polymer. More preferably, the metal particles are
from 20 PPM to 100 PPM of the thermoplastic polymer. Most
preferably, the metal particles are from 25 PPM to 100 PPM of the
thermoplastic polymer.
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The particle size d50 of the mentioned metal particles is from 0.1
to 100 m. Preferably, the particle size d5o of the mentioned metal
particles is from 0.1 to 50 m. More preferably, the particle size d5o of
the mentioned metal particles is from 0. 1 to 10 m. Most preferably,
the particle size d5o of the mentioned metal particles is from 0. 1 to 5 m.
Because the metal particles can be added in every polymerizing
stage of thermoplastic polymer, the molecular weight of the
thermoplastic polymer in the composition of this embodiment contains
the degree of polymerization range in melt state polycondensation stage
is usually about 10 - 100 and in solid state polymerization it is usually
about 100 - 400. That is, the number average, molecular weight (Mn)
of the thermoplastic polymer according to this embodiment is about
1,000 - 60,000. Selectively, the number average molecular weight (Mn)
of the thermoplastic polymer is about 1,000 - 45,000. Further
selectively, the number of average molecular weight (Mn) the
thermoplastic polymer is about 1,000 - 35,000. In one preferred
example of this invention, the number average molecular weight (Mn) of
the thermoplastic polymer in each polymerizing stage is separately
1,350, 19,000, and 31,000.
The thermoplastic polymer composition of this embodiment can
be used to fabricate melt, pellet, sheet, or container. In one preferred
example, the thermoplastic polymer composition according to this
embodiment is suitable for bottle preform and bottle manufacturing.
In one preferred example, a bottle preform made of the
thermoplastic polymer composition according to this invention is
disclosed. Preferably, the mentioned bottle preform is with brightness
L* between 75% and 100%, and with haze from 2 - 8.1. More
preferably, the bottle preform is with brightness L* between 80% and
100%, and with haze from 2 - 3.5. Preferably, the mentioned bottle
preform is with a* between -3 and +3. More preferably, the mentioned
bottle preform is with a* between -2 and +2. More preferably, a* of the
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mentioned bottle preform is about -2 to 0. Preferably, the mentioned
bottle preform is with b* between -5 and +7. More preferably, the
mentioned bottle preform is with b* between -5 and +5. More
preferably, the b* of the mentioned bottle preform is about 0 to +5. In
one preferred example of this embodiment, the produced bottle preform
is with haze between 3.5 and 8.1, a* between -1.36 to -1.42, and b*
between 4.73 and 4.98.
In another preferred example, a bottle made of the thermoplastic
polymer composition according to this invention is disclosed.
Preferably, the mentioned bottle is with brightness L* between 88% and
100%, and with haze from 1 - 4. Preferably, the mentioned bottle is
with a* between -1 and + 1. Preferably, the mentioned bottle is with a*
between -0.5 and +0.5. More preferably, the mentioned bottle is with
a* between -0.5 and 0. Preferably, the mentioned bottle is with b*
between -3 and +5. More preferably, the mentioned bottle is with b*
between -1 and +4. More preferably, the b* of the mentioned bottle is
about 0 to +3. In one preferred example of this embodiment, the
produced bottle is with haze between 2.1 and 4, a* between -0.36 to
-0.47, and b* between 2.41 and 2.59 (almost achromatic).
In this specification, the value of L*, a*, and b* are detected by
Macbeth color eye 2145 spectrometer with 1976 CIE L* a* b* color
presentation. In the detection, the ovserving angel is 2 , and the light
source is D65. When the detected sample is bottle preform, the
sample thickness is set as 4 mm. When the detected sample is bottle,
the sample thickness is set as 0.35 mm. About the detecting result,
the value of L* is larger means that the brightness of the sample is
higher. That a* > 0 means that the color of the sample is close to red,
and a* < 0 means that the color of the sample is close to green. That b*
> 0 means that the color of the sample is close to yellow, and b* < 0
means that the color of the sample is close to blue. The haze of the
sample is detected with a HAZE SUGA instrument by ASTM-D 1003
method.
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Another embodiment of this invention discloses a method for
preparing fast heat-up thermoplastic polymer composition. The
mentioned method for preparing fast heat-up thermoplastic polymer
composition comprises the following step: adding metal particles into
thermoplastic polymer during stage selected from the following: slurry
stage, esterfication stage, melt state polycondensation stage and any
other post-polymerization melt process, or forming stage. In one
preferred example of this embodiment, the metal particles are added
into the thermoplastic polymer during the melt sate polycondensation
stage. In another preferred example of this embodiment, the addition
of the metal particles into the thermoplastic polymer can be performed
in once or multiple stages. In another preferred example of this
embodiment, according to the requirement of the manufacture, the
metal particles can be dispersed into a liquid medium before adding
into the mentioned polymerization or forming stage. Preferably, the
liquid medium is ethylene glycol.
Moreover, if the metal particles are added in the forming stage,
such as during injecting the bottle preform, the metal particles are
preferably dried before added. Besides, in order to decrease the
pollution of the process line, the metal particles can be well-mixed
with part of the polymer pellet by estrusion operation to form
"masterbatch", and then the masterbatch is employed in the production
line in a large number.
The preferred examples of thermoplastic polymer composition
and the preparation thereof according to the application are described
in the following. However, the scope of this application should be
based on the claims, but is not restricted by the following examples.
General detection:
Unless additional description, all the detection are going through
with the following methods under normal temperature and normal
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atmosphere.
1. Intrinsic Viscosity measurement: dissolving 0.1 g sample into
25 cc solvent, wherein the solvent includes phenol and CC14 in volume
ratio 3:2, and then measuring the solution with Ubbelohde viscosity
meter at 30 C.
2. L*, a*, and b*: measured by Macbeth color eye 2145
spectrometer with 1976 CIE L* a* b* color presentation, the operating
parameter and the meaning of L*, a*, and b* are as the
above-mentioned description.
3. Haze: measured with a HAZE SUGA instrument by method
ASTM-D 1003.
4. "Percent Reheat improvement" is calculated as following:
% Reheat improvement = (bottle preform surface temperature of
comparison example - bottle preform surface temperature of
example) / (bottle preform surface temperature of example) x 100%
Example 1
Liquid polymerization stage
38 Kg terephthalic acid (TPA), 0.9 Kg isophthalic acid (IPA), and
18.16 Kg ethylene glycol (EG) with 1.125 g aluminum particles (d5o is 2
1 m) are added into a stirring tank, and the mixture is stirred to
become a paste. The paste is poured into an esterification tank, and
the temperature of the esterification tank is raised with an end
temperature at 250 C for 6.5 hours for processing esterification.
When over 95% the esterification degree, a polymer product is obtained
wherein the polymer product is polyester with polymerization degree
about 7, and the number of average of molecular weight is about 1350.
The polymer product is transferred to a polymerization tank, and 1260
g catalyst (Sb203) and 35 PPM anti-oxidant (H3PO4) are added into the
polymerization tank. The polymerization tank is heated and
vacuumed until the intrinsic viscosity of the mixture is about 0.6 dL/g
(number of average of molecular weight is about 19000). After
executing cutting, PET melt state polycondensation co-polyester pellet
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doped with aluminum particles is obtained. The added amount of the
aluminum particles is 25 PPM based on PET weight.
Solid phase polymerization
After pouring the melt state polycondensation pellet into a solid
phase polymerizing tank, the temperature of the mentioned tank is
raised to 85 C for drying for 2.5 hours. Then, the temperature of the
tank is raised to 105 C for drying for 3 hours. Subsequently, the
temperature of the tank is raised to 150 C for pre-crystallizing for 2
hours. Then, the temperature of the tank is raised to 235 C until the
intrinsic viscosity of the mixture is about 0.85 dL/g (number of average
of molecular weight is about 31,000). After cutting, PET solid state
polymerization co-polyester pellet doped with aluminum particles is
obtained.
Because EG is overdosed and part of EG are dehydrated to form
DEG during polymerization, the repeat unit of the PET co-polyester
from solid state polymerization can be identified through calculating
the added amount of TPA and IPA, wherein the added TPA and IPA are
totally reacted, and employing GC (Perkin Elmer auto system) to
measuring the DEG amount in the co-polyester. In the PET
co-polyester, based on the total mole of the repeat unit A, the repeat
unit A derived from TPA and IPA are separately 97.7 mol% and 2.3
mol%. Based on the total mole of the repeat unit B, the repeat unit B
derived from EG and DEG are separately 97.6 mol% and 2.4 mol%.
Bottle preform injection
Solid state polymerization polyester pellet is dried under 160 C
for 5 hours, and then poured into an injecting machine manufactured
by Jonwai Machinery Works Corp. Ltd. Through the injecting machine,
bottle preform is injected at 275 C - 280 C.
Bottle blowing stage
The injected bottle preform is put into a blowing machine made
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by CHIA MING Machinery Co., Ltd., heated at 105 C by quartz tube for
50 seconds, and then an infrared temperature sensor is employed to
measure the surface temperature of the bottle preform.
The measured surface temperature data of the bottle preform is
shown as Table 1. Subsequently, the heat-softened bottle preform is
put into blowing mold, and blown to form bottle by nitrogen at
18-32Kg/cm3. The measured physical data of the bottle preform and
the bottle is shown as Table 1 and Table 2.
Example 2
Except adding 50 PPM Aluminum powder in the melt state
polycondensation stage, in this example, all the condition is just as the
Example 1. After solid state polymerization, the repeat unit of the PET
co-polyester pellet of this Example is the same as that of Example 1.
The measured data of the bottle preform and the bottle of this example
is shown as Table 1 and Table 2.
Example 3
Except adding 100 PPM Aluminum powder in the melt state
polycondensation stage, in this example, all the condition is just as the
Example 1. After solid state polymerization, the repeat unit of the PET
co-polyester pellet of this Example is the same as that of Example 1.
The measured data of the bottle preform and the bottle of this example
is shown as Table 1 and Table 2.
Example 4
Except adding 25 PPM Aluminum powder (d5o is 0.1 0.05 m )
in the melt state polycondensation stage, in this example, all the
condition is just as the Example 1. After solid state polymerization,
the repeat unit of the PET co-polyester pellet of this Example is the
same as that of Example 1. The measured data of the bottle preform
and the bottle of this example is shown as Table 1 and Table 2.
Comparison Example
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Except not adding any Aluminum in the melt state
polycondenssation stage, in this example, all the condition is just as the
Example 1. After solid state polymerization, the repeat unit of the PET
co-polyester pellet of this Example is the same as that of Example 1.
The measured data of the bottle preform and the bottle of this example
is shown as Table I and Table 2.
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Table 1
Conc.
Surface Reheat
bottle of Al particle
temp. Improv. Haze L* a* b*
preform powder size
(0C) (%)
(ppm)
Comparison
0 2 m 113 0 2.2 82.43 -1.36 4.85
example
Example 1 25 2 m 118 4.42 3.5 81.5 -1.37 4.9
Example 2 50 2 m 122 7.96 5.6 79.94 -1.41 4.98
Example 3 100 2 m 129 14.15 8.1 78.31 -1.42 4.73
Example 4 25 0.1 m 119 5.31 3.0 82.1 -1.37 4.8
Table 2
Conc. of
Al particle
bottle Haze L* a* b*
powder size
(ppm)
Comparison
0 2 m 1.0 89.81 -0.36 2.90
example
Example 1 25 2 m 2.1 90.94 -0.47 2.41
Example 2 50 2 m 3.6 90.50 -0.46 2.41
Example 3 100 2 m 4 89.71 -0.46 2.59
Example 4 25 0.1 m 1.5 90.82 -0.45 2.54
According to the above Table 1 and Table 2, though the Haze of
the bottle preforms from Example 2 and Example 3 are a little high,
after blowing stage, all the bottles of comparison example and Example
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1 - 4 can achieve the commercial requirement range on brightness (L* -
90) and haze (Haze < 4). Besides, through comparing the bottle
preform surface temperature, for those example doped with aluminum
powder, the heating time of the bottle preform is efficiently shortened,
and the produced bottles in the examples doped with aluminum powder
are almost achromatic and transparent especially using smaller
particle size of aluminum powder. Therefore, the bottle preform in the
examples according to this invention can achieve higher surface
temperature than those bottle preform without aluminum powder in
the same heating time.
To sum up, this present application discloses a fast heat-up
thermoplastic polymer composition and preparation thereof. Through
adding metal particles with high thermal conductivity into the
manufacturing stages, thermoplastic polymer composition according to
this application is obtained. The mentioned thermoplastic polymer
composition is not only fast heat-up in re-heating stage, especially in
bottle preform re-heating stage, but also can be used to fabricate almost
achromatic and transparent final product, especially to fabricate bottle,
wherein the final product can satisfy the commercial requirement on
achromatic container. In the prior art, thermoplastic polymer
composition can be fast heat-up in the re-heating stage by adding
black-body or gray-body absorption particles into the thermoplastic
polymer, and then a final product can be formed thereof with color and
without transparency. Therefore, this application provides an
economic method to fabricate thermoplastic polymer product by
employing fast heat-up thermoplastic polymer composition to save
re-heating energy. Besides, the above-mentioned thermoplastic
polymer composition according to this application is enough
achromatic and transparent to satisfy commercial requirement on
achromatic containers.
Obviously many modifications and variations are possible in light
of the above teachings. It is therefore to be understood that within the
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scope of the appended claims the present invention can be practiced
otherwise than as specifically described herein. Although specific
embodiments have been illustrated and described herein, it is obvious
to those skilled in the art that many modifications of the present
invention may be made without departing from what is intended to be
limited solely by the appended claims.
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