U.S. patent application number 11/079903 was filed with the patent office on 2005-11-03 for macrocyclic polyester oligomers and processes for polymerizing the same.
This patent application is currently assigned to Cyclics Corporation. Invention is credited to Takekoshi, Tohru, Winckler, Steven J..
Application Number | 20050245676 11/079903 |
Document ID | / |
Family ID | 27390858 |
Filed Date | 2005-11-03 |
United States Patent
Application |
20050245676 |
Kind Code |
A1 |
Winckler, Steven J. ; et
al. |
November 3, 2005 |
Macrocyclic polyester oligomers and processes for polymerizing the
same
Abstract
A water slurry process is used to prepare a prepreg and to
manufacture articles from macrocyclic polyester oligomers. In one
embodiment, a process for preparing a water suspension of
macrocyclic polyester oligomers includes the steps of contacting a
macrocyclic polyester oligomer and a polymerization catalyst with
water and a surfactant, and mixing the macrocyclic polyester
oligomer and polymerization catalyst with water and the surfactant
thereby forming a suspension. In another embodiment, a process for
impregnating macrocyclic polyester oligomers for polymerization
includes the steps of providing a suspension of a macrocyclic
polyester oligomer and a polymerization catalyst in water, applying
the suspension to a base material, drying to remove water from the
suspension, and pressing the dried suspension to a desired form. In
yet another embodiment, a composition of macrocyclic polyester
oligomer includes a macrocyclic polyester oligomer, a
polymerization catalyst and water. In yet another embodiment, a
process for polymerizing macrocyclic polyester oligomers includes
the steps of mixing a blend material having a macrocyclic polyester
oligomer and a polymerization catalyst with water to form a
mixture, applying the mixture to a base material, drying to remove
water, heating to polymerize the macrocyclic polyester oligomer,
and pressing the polymerized macrocyclic polyester oligomer to a
desired form.
Inventors: |
Winckler, Steven J.; (Troy,
NY) ; Takekoshi, Tohru; (Scotia, NY) |
Correspondence
Address: |
GOODWIN PROCTER LLP
PATENT ADMINISTRATOR
EXCHANGE PLACE
BOSTON
MA
02109-2881
US
|
Assignee: |
Cyclics Corporation
Schenectady
NY
|
Family ID: |
27390858 |
Appl. No.: |
11/079903 |
Filed: |
March 14, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11079903 |
Mar 14, 2005 |
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10408753 |
Apr 7, 2003 |
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10408753 |
Apr 7, 2003 |
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10195853 |
Jul 15, 2002 |
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6639009 |
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10195853 |
Jul 15, 2002 |
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09754943 |
Jan 4, 2001 |
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6420047 |
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09754943 |
Jan 4, 2001 |
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09535132 |
Mar 24, 2000 |
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6369157 |
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60177727 |
Jan 21, 2000 |
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Current U.S.
Class: |
524/599 ;
428/480 |
Current CPC
Class: |
C08G 63/85 20130101;
B29C 67/246 20130101; Y10T 428/31786 20150401; B29C 41/06
20130101 |
Class at
Publication: |
524/599 ;
428/480 |
International
Class: |
B32B 027/06; C08K
003/00 |
Claims
1-27. (canceled)
28. A rotational molding process comprising the steps of: (a)
loading a blend material into a mold comprising a chamber, the
blend material comprising: (i) a macrocyclic polyester oligomer;
and (ii) a polymerization catalyst, wherein the macrocyclic
polyester oligomer comprises a structural repeat unit of the
formula 27wherein A is an alkylene, a cycloalkylene, or a mono- or
polyoxyalkylene group and B is a divalent aromatic or alicyclic
group; (b) rotating the mold along at least one axis; and (c)
applying heat to polymerize the macrocyclic polyester oligomer.
29. The rotational molding process of claim 28, wherein the blend
material is stored at ambient conditions for at least one week
before loading into the mold.
30. The rotational molding process of claim 28, wherein step (b)
comprises rotating the mold along at least two axes.
31. The rotational molding process of claim 28, wherein the
macrocyclic polyester oligomer comprises macrocyclic PBT
oligomer.
32. The rotational molding process of claim 31, wherein step (c)
comprises heating the blend material to a temperature below
220.degree. C.
33. The rotational molding process of claim 31, wherein step (c)
comprises heating the blend material to a temperature within a
range from about 180.degree. C. to about 220.degree. C.
34. The rotational molding process of claim 28, wherein the
macrocyclic polyester oligomer comprises macrocyclic PBT/PET
co-oligomer.
35. The rotational molding process of claim 34, wherein step (c)
comprises heating the blend material to a temperature below
240.degree. C.
36. The rotational molding process of claim 34, wherein step (c)
comprises heating the blend material to a temperature within a
range from about 180.degree. C. to about 240.degree. C.
37. The rotational molding process of claim 28, wherein step (c)
comprises heating the blend material to a temperature below the
melting point of the polymerized product.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. Utility
patent application Ser. No. 09/535,132 (Attorney Docket No.
CYC-034) filed on Mar. 24, 2000. This application also claims the
benefit of the filing date of U.S. Provisional Patent Application
Ser. No. 60/177,727, filed on Jan. 21, 2000, entitled "Processing
with Cyclic PBT to Produce Thermoplastic Compositions" by Winckler.
The entirety of these applications is incorporated herein by
reference.
TECHNICAL FIELD
[0002] This invention generally relates to thermoplastics and
articles formed therefrom. More particularly, the invention relates
to a blend material prepared from a macrocyclic polyester oligomer
and a polymerization catalyst, and processes of using the same.
BACKGROUND INFORMATION
[0003] Linear polyesters such as poly(alkylene terephthalate) are
generally known and commercially available where the alkylene
typically has 2 to 8 carbon atoms. They have many valuable
characteristics including strength, toughness, high gloss and
solvent resistance. Linear polyesters are conventionally prepared
by the reaction of a diol with a dicarboxylic acid or its
functional derivative, typically a diacid halide or ester. Linear
polyesters may be fabricated into articles of manufacture by a
number of known techniques including extrusion, compression
molding, and injection molding.
[0004] Recently, macrocyclic polyester oligomers were developed
which have unique properties. These properties make them attractive
as matrices for engineering thermoplastic composites. These
desirable properties stem from the fact that macrocyclic polyester
oligomers exhibit low melt viscosity, allowing them to impregnate a
dense fibrous preform easily. Furthermore, certain macrocyclic
polyester oligomers melt and polymerize at temperatures well below
the melting point of the resulting polymer. Upon melting and in the
presence of an appropriate catalyst, polymerization and
crystallization can occur virtually isothermally. As a result, the
time and expense required to thermally cycle a tool is favorably
reduced.
[0005] Development of processing equipment for use with macrocyclic
polyester oligomers has been limited. It is generally believed that
production of molded parts from macrocyclic polyester oligomers
requires existing equipment to be modified to allow for transfer of
the macrocyclic polyester oligomers and polymerization catalysts
into the equipment in the appropriate amounts at the appropriate
time and at the appropriate temperature. Modifying existing
equipment takes time and is often costly, and hence limits the
application of macrocyclic polyester oligomers.
SUMMARY OF THE INVENTION
[0006] A blend of a macrocyclic polyester oligomer and a
polymerization catalyst as a one component ready-to-use material
with a long shelf life enables production of parts from macrocyclic
polyester oligomers without the modification of existing equipment,
thereby reducing time and cost of manufacture while expanding the
application of macrocyclic polyester oligomers. In this blend
material, the macrocyclic polyester oligomer remains intact in
solid state at ambient conditions. Upon melting, the blend material
initially forms a low viscosity fluid, and then rapidly polymerizes
to form high molecular weight polyesters which subsequently
solidify to form semi-crystalline polymers. In the case of certain
macrocyclic polyester oligomers, for example, poly(1,4-butylene
terephthalate), demolding can take place at the polymerization
temperature, e.g., at about 180.degree. C. to 200.degree. C.,
because the resulting polyester polymer solidifies fairly rapidly
at that temperature without cooling.
[0007] In one aspect, the invention generally features a blend
material that includes a macrocyclic polyester oligomer, a
polymerization catalyst and optionally, a filler. In one
embodiment, the macrocyclic polyester oligomer is substantially a
homo- or co-polyester oligomer. Polymerization catalysts include,
among others, tin compounds and titanate compounds.
[0008] In another aspect, the invention generally features a
process for preparing a blend material as described above.
[0009] In yet another aspect, the invention features processes such
as rotational molding, resin film infusion, pultrusion, resin
transfer molding, filament winding, making and using powder coated
or hot melt prepreg, compression molding, roll wrapping, and water
slurry, which use the blend material described above. These
processes of the invention may be used to form polyester polymer
composites which may be included in articles of manufacture such as
carbon fiber golf shafts or lightweight automotive chassis
members.
[0010] In one aspect, a water slurry process is used to prepare a
prepreg and to manufacture articles from macrocyclic polyester
oligomers. In one embodiment, a process for preparing a water
suspension of macrocyclic polyester oligomers includes the steps of
contacting a macrocyclic polyester oligomer and a polymerization
catalyst with water and a surfactant, and mixing the macrocyclic
polyester oligomer and polymerization catalyst with water and the
surfactant thereby forming a suspension. In another embodiment, a
process for impregnating macrocyclic polyester oligomers for
polymerization includes the steps of providing a suspension of a
macrocyclic polyester oligomer and a polymerization catalyst in
water, applying the suspension to a base material, drying to remove
water from the suspension, and pressing the dried suspension to a
desired form. In yet another embodiment, a composition of
macrocyclic polyester oligomer includes a macrocyclic polyester
oligomer, a polymerization catalyst, and water. In yet another
embodiment, a process for polymerizing macrocyclic polyester
oligomers includes the steps of mixing a blend material having a
macrocyclic polyester oligomer and a polymerization catalyst with
water to form a mixture, applying the mixture to a base material,
drying to remove water, heating to polymerize the macrocyclic
polyester oligomer, and pressing the polymerized macrocyclic
polyester oligomer to a desired form.
[0011] Thus, heating may be applied such that, after drying the
mixture, there is no polymerization, partial polymerization or
complete polymerization of the macrocyclic polyester oligomer.
[0012] The foregoing and other objects, aspects, features, and
advantages of the invention will become more apparent from the
following figures, description, and claims.
BRIEF DESCRIPTION OF FIGURES
[0013] The drawings are not necessarily to scale, emphasis instead
is generally placed upon illustrating the principles of the
invention to facilitate its understanding.
[0014] FIG. 1 is a schematic illustration of an embodiment of the
invention including a rotational molding process.
[0015] FIG. 2 is a schematic illustration of an embodiment of the
invention including a resin film infusion process.
[0016] FIG. 3 is a schematic illustration of an embodiment of the
invention including a solvent prepreg process.
[0017] FIG. 4 is a schematic illustration of an embodiment of the
invention including a hot-melt prepreg process.
[0018] FIG. 5 is a schematic illustration of an embodiment of the
invention including a pultrusion process.
[0019] FIG. 6 is a schematic illustration of an embodiment of the
invention including an extruder.
[0020] FIG. 7 is a schematic illustration of an embodiment of the
invention including a piston type continuous melter.
[0021] FIG. 8 is a schematic illustration of an embodiment of the
invention including a resin transfer molding process.
[0022] FIG. 9 is a schematic illustration of an embodiment of the
invention including a filament winding process.
[0023] FIG. 10 is a schematic illustration of an embodiment of the
invention including a compression molding process.
[0024] FIG. 11 is a schematic illustration of an embodiment of the
invention including a roll wrapping process.
[0025] FIG. 12 is a schematic illustration of an embodiment of the
invention including a powder coating process.
[0026] FIG. 13 is a schematic illustration of an embodiment of the
invention including a water slurry process.
[0027] FIG. 14 is a schematic illustration of another embodiment of
the invention including a water slurry process.
DESCRIPTION
[0028] The present invention is directed to the surprising
discovery that a blend material comprising a macrocyclic polyester
oligomer and a polymerization catalyst provides superior processing
characteristics relative to conventional thermoplastics precursors.
Prior to this invention, it was not recognized that a mixture of a
macrocyclic polyester oligomer and a polymerization catalyst can be
stable and have a long shelf life. The blend material of the
invention allows for easy production, storage, transportation and
processing.
[0029] From the standpoint of applications, the blend material is
one-component and is ready-to-use. The blend material may be used
advantageously for manufacturing articles using processes such as
injection and rotational molding, resin film infusion, resin
transfer molding, filament winding, powder coating to create a
prepreg or film, hot melt prepreg preparation, compression molding,
roll wrapping, water slurry, and pultrusion with or in some cases
without reinforcement. The blend material may also be processed
like a thermoset while producing a thermoplastic product.
Furthermore, the blend material eliminates the need to modify
existing equipment to allow for transfer of the macrocyclic
polyester oligomer and the polymerization catalyst into the
equipment in the appropriate amounts at the appropriate time and at
the appropriate temperature. Accordingly, this invention provides
for ways to achieve greater production efficiency and lower
manufacturing costs.
[0030] Definitions
[0031] The following general definitions may be helpful in
understanding the various terms and expressions used in this
specification.
[0032] As used herein, a "blend material" is understood to mean a
mixture of two or more components including at least one
macrocyclic polyester oligomer and at least one polymerization
catalyst. Preferably the blend material is uniformly mixed. A blend
material may also include a filler as well as other components
recognized by a skilled artisan.
[0033] As used herein, "macrocyclic" is understood to mean a cyclic
molecule having at least one ring within its molecular structure
that contains 8 or more atoms covalently connected to form the
ring.
[0034] As used herein, an "oligomer" is understood to mean a
molecule that contains 2 or more identifiable structural repeat
units of the same or different formula.
[0035] As used herein, a "macrocyclic polyester oligomer" is
understood to mean a macrocyclic oligomer containing structural
repeat units having an ester functionality. A macrocyclic polyester
oligomer typically refers to multiple molecules of one specific
formula. However, a macrocyclic polyester oligomer also may include
multiple molecules of different formulae having varying numbers of
the same or different structural repeat units. In addition, a
macrocyclic polyester oligomer may be a co-polyester or
multi-polyester oligomer, i.e., an oligomer having two or more
different structural repeat units having an ester functionality
within one cyclic molecule.
[0036] As used herein, "substantially homo- or co-polyester
oligomer" is understood to mean a polyester oligomer wherein the
structural repeat units are substantially identical or
substantially two different structural repeat units,
respectively.
[0037] As used herein, "an alkylene group" is understood to mean
--C.sub.nH.sub.2n-, where n.gtoreq.2.
[0038] As used herein, "a cycloalkylene group" is understood to
mean a cyclic alkylene group, --C.sub.nH.sub.2n-x--, where x
represents the number of H's replaced by cyclization(s).
[0039] As used herein, "a mono- or polyoxyalkylene group" is
understood to mean
[--(CH.sub.2).sub.m--O--].sub.n--(CH.sub.2).sub.m--, wherein m is
an integer greater than 1 and n is an integer greater than 0.
[0040] As used herein, "a divalent aromatic group" is understood to
mean an aromatic group with links to other parts of the macrocyclic
molecule. For example, a divalent aromatic group may include a
meta- or para-linked monocyclic aromatic group (e.g., benzene).
[0041] As used herein, "an alicyclic group" is understood to mean a
non-aromatic hydrocarbon group containing a cyclic structure
within.
[0042] As used herein, "a C.sub.1-4 primary alkyl group" is
understood to mean an alkyl group having 1 to 10 carbon atoms which
includes straight chain or branched molecules.
[0043] As used herein, "a C.sub.1-10 alkyl group" is understood to
mean an alkyl group connected via a primary carbon atom.
[0044] As used herein, a "methylene group" is understood to mean
--CH.sub.2--.
[0045] As used herein, an "ethylene group" is understood to mean
--CH.sub.2--CH.sub.2--.
[0046] As used herein, "a C.sub.2-3 alkylene group" is understood
to mean --C.sub.nH.sub.2n--, where n is 2 or 3.
[0047] As used herein, "a C.sub.2-6 alkylene group" is understood
to mean --C.sub.nH.sub.2n--, where n is 2-6.
[0048] As used herein, "substitute phenyl group" is understood to
mean a phenyl group having one or more substituents. A substituted
phenyl group may have substitution pattern that is recognized in
the art. For example, a single substituent may be in the ortho,
meta or para positions. For multiple substituents, typical
substitution patterns include, for example, 2,6-,2,4,6-, and,
3,5-substitution patterns.
[0049] As used herein, "a filler" is understood to mean a material
other than a macrocyclic polyester oligomer or a polymerization
catalyst that may be included in the blend material. A filler often
is included to achieve a desired purpose or property, and may be
present in the resulting polyester polymer. For example, the
purpose of the filler may be to provide stability, such as
chemical, thermal or light stability, to the blend material or the
polyester polymer product, and/or to increase the strength of the
polyester polymer product. A filler also may provide or reduce
color, provide weight or bulk to achieve a particular density,
provide flame resistance (i.e., be a flame retardant), be a
substitute for a more expensive material, facilitate processing,
and/or provide other desirable properties as recognized by a
skilled artisan. Illustrative examples of fillers are, among
others, fumed silica, titanium dioxide, calcium carbonate, chopped
fibers, fly ash, glass microspheres, micro-balloons, crushed stone,
nanoclay, linear polymers, and monomers.
[0050] As used herein, "a polyester polymer composite" is
understood to mean a polyester polymer that is associated with
another substrate such as, a fibrous or particulate material.
Illustrative examples of particulate material are chopped fibers,
glass microspheres, and crushed stone. Certain fillers thus can be
used to prepare polyester polymer composites.
[0051] As used herein, a "fibrous substrate" is understood to mean
more continuous substrate, e.g., fiberglass, ceramic fibers, carbon
fibers or organic polymers such as aramid fibers.
[0052] 1. Macrocyclic Polyester Oligomers
[0053] One of the ingredients of the blend material of the
invention is a macrocyclic polyester oligomer. Many different
macrocyclic polyester oligomers can readily be made and are useful
in the practice of this invention. Thus, depending on the desired
properties of the final polyester polymer product, the appropriate
macrocyclic polyester oligomer(s) can be selected for use in its
manufacture.
[0054] Macrocyclic polyester oligomers that may be employed in this
invention include, but are not limited to, macrocyclic
poly(alkylene dicarboxylate) oligomers having a structural repeat
unit of the formula: 1
[0055] where A is an alkylene, or a cycloalkylene or a mono- or
polyoxyalkylene group; and B is a divalent aromatic or alicyclic
group.
[0056] Preferred macrocyclic polyester oligomers are macrocyclic
poly(1,4-butylene terephthalate) (PBT), poly(1,3-propylene
terephthalate) (PPT), poly(1,4-cyclohexylenedimethylene
terephthalate) (PCT), poly(ethylene terephthalate) (PET), and
poly(1,2-ethylene 2,6-naphthalenedicarboxylate) (PEN) oligomers,
and copolyester oligomers comprising two or more of the above
monomer repeat units.
[0057] Macrocyclic polyester oligomers may be prepared by known
methods. Synthesis of the preferred macrocyclic polyester oligomers
may include the step of contacting at least one diol of the formula
HO-A-OH with at least one diacid chloride of the formula: 2
[0058] where A and B are as defined above. The reaction typically
is conducted in the presence of at least one amine that has
substantially no steric hindrance around the basic nitrogen atom.
An illustrative example of such amines is
1,4-diazabicyclo[2.2.2]octane (DABCO). The reaction usually is
conducted under substantially anhydrous conditions in a
substantially water immiscible organic solvent such as methylene
chloride. The temperature of the reaction typically is between
about -25.degree. C. and about 25.degree. C. See, e.g., U.S. Pat.
No. 5,039,783 to Brunelle et al.
[0059] Macrocyclic polyester oligomers have also been prepared via
the condensation of a diacid chloride with at least one
bis(hydroxyalkyl)ester such as bis(4-hydroxybutyl) terephthalate in
the presence of a highly unhindered amine or a mixture thereof with
at least one other tertiary amine such as triethylamine, in a
substantially inert organic solvent such as methylene chloride,
chlorobenzene, or a mixture thereof. e.g., U.S. Pat. No. 5,231,161
to Brunelle et al.
[0060] Another method for preparing macrocyclic polyester oligomers
or macrocyclic copolyester oligomers is to depolymerize linear
polyester polymers in the presence of an organotin or titanate
compound. In this method, linear polyesters are converted to
macrocyclic polyester oligomers by heating a mixture of linear
polyesters, an organic solvent, and a trans-esterification catalyst
such as a tin or titanium compound. The solvents used, such as
o-xylene and o-dichlorobenzene, usually are substantially free of
oxygen and water. See, e.g., U.S. Pat. No. 5,407,984 to Brunelle et
al. and U.S. Pat. No. 5,668,186 to Brunelle et al.
[0061] It is also within the scope of the invention to employ
macrocyclic homo- and co-polyester oligomers to produce homo- and
co-polyester polymers, respectively. Therefore, unless otherwise
stated, an embodiment of a composition, article, or process that
refers to a macrocyclic polyester oligomer also includes
co-polyester embodiments.
[0062] II. Polymerization Catalysts
[0063] The other primary ingredient of the blend material of the
invention is a polymerization catalyst. The polymerization
catalysts that may be employed in the invention are capable of
catalyzing the polymerization of the macrocyclic polyester
oligomer. As with state-of-the-art processes for polymerizing
macrocyclic polyester oligomers, organotin and organotitanate
compounds are the preferred catalysts, although other catalysts may
be used. For example, organotin compound
1,1,6,6-tetra-n-butyl-1,6-distanna-2,5,7,10-tetraoxacyclodecane may
be used as polymerization catalyst Other illustrative organotin
compounds include n-butyltin(IV) chloride dihydroxide,
dialkyltin(V) oxides, such as di-n-butyltin(IV) oxide and
di-n-octyltin oxide, and acyclic and cyclic monoalkyltin (IV)
derivatives such as n-butyltin tri-n-butoxide, dialkytin (IV)
dialkoxides such as di-n-butyltin(IV) di-n-butoxide and
2,2-di-n-butyl-2-stanna-1,3-dioxacycloheptaiie, and trialkyltin
alkoxides such as tributyltin ethoxide. See, e.g., U.S. Pat. No.
5,348,985 to Pearce et al.
[0064] Also, trisstannoxanes having the general formula (I) shown
below can be used as a polymerization catalyst to produce branched
polyester polymers. 3
[0065] where R.sub.2 is a C.sub.1-4 primary alkyl group and R.sub.3
is C.sub.1-10 alkyl group.
[0066] Additionally, organotin compounds with the general formula
(II) shown below can be used as a polymerization catalyst to
prepare branched polyester polymers from macrocyclic polyester
oligomers. 4
[0067] where R.sub.3 is defined as above.
[0068] As for titanate compounds, tetra(2-ethylhexyl) titanate,
tetraisopropyl titanate, tetrabutyl titanate, and titanate
compounds with the general formula (III) shown below can be used as
polymerization catalysts. 5
[0069] wherein: each R.sub.4 is independently an alkyl group, or
the two R.sub.4 groups taken together form a divalent aliphatic
hydrocarbon group; R.sub.5 is a C.sub.2-10 divalent or trivalent
aliphatic hydrocarbon group; R.sub.6 is a methylene or ethylene
group; and n is 0 or 1.
[0070] Examples of titanate compounds with the above general
formula are shown in Table 1.
1TABLE 1 Examples of Titanate Compounds Having Formula (III) 6 7 8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
[0071] Titanate ester compounds having at least one moiety of the
following general formula have also been used as polymerization
catalysts: 25
[0072] wherein:
[0073] each R.sub.7 is independently a C.sub.2-3 alkylene
group;
[0074] R.sub.8 is a C.sub.1-4 alkyl group or unsubstituted or
substituted phenyl group;
[0075] Z is O or N; provided when Z is O, m=n=0, and when Z is N,
m=0 or 1 and m+n=1;
[0076] each R.sub.9 is independently a C.sub.2-6 alkylene group;
and q is 0 or 1
[0077] Typical examples of such titanate compounds are shown below
as formula (VI) and formula (VII): 26
[0078] III. The Blend Material
[0079] This invention provides a blend material and processes for
preparing the blend material which includes a macrocyclic polyester
oligomer and a polymerization catalyst. The blend material allows
for easy production, storage, transportation and processing. From
the standpoint of applications, the blend material is a
one-component ready-to-use mixture. The blend material may also be
processed like a thermoset while producing a thermoplastic.
Furthermore, the blend material eliminates the need that existing
equipment be modified to allow for transfer of the macrocyclic
polyester oligomer and a polymerization catalyst into the equipment
in the appropriate amounts at the appropriate time and at the
appropriate temperature.
[0080] There is no limitation with respect to the physical form of
the macrocyclic polyester oligomer when mixed with the
polymerization catalyst as long as the macrocyclic polyester
oligomer remains substantially chemically intact. In one
embodiment, the macrocyclic polyester oligomer is a solid such as a
powder. In this embodiment, mechanical mixing typically is used to
mix the macrocyclic polyester oligomer with a polymerization
catalyst. In another embodiment, the macrocyclic polyester oligomer
is mixed in the presence of a solvent with the solvent remaining
present during the step of mixing.
[0081] In one embodiment, the blend material also includes a
filler. Illustrative examples of such fillers include pigments,
light weight fillers, flame retardants, and ultraviolet light
stabilizers. For example, calcium carbonate may be used to increase
the thickness of a polyester polymer product to improve its
mechanical performance. Also, glass microspheres may be added to
lower the density of the product. Other fillers include nanoclays,
e.g., to increase the modulus of the product, organo bromides in
combination with antimonium oxides, e.g., to impart flame
resistance, and colorants such as carbon black or titanium dioxide.
Fillers thus can be used to prepare polyester polymer
composites.
[0082] The filler is added generally between about 0.1% and 70% by
weight, between about 25% and 70% by weight, or between about 2%
and 5% by weight depending on the filler and the purpose for adding
the filler. For example, the percentage is preferably between 25%
and 50% by weight in the case of calcium carbonate, between 2% and
5% by weight in the case of nanoclays, between 0.1% and 1% in the
case of pigments, and between 25% and 70% by weight in the case of
glass microspheres.
[0083] A process for preparing the blend material includes
providing a macrocyclic polyester oligomer and mixing the
macrocyclic polyester oligomer with a polymerization catalyst. When
preparing the blend, the macrocyclic polyester oligomer and the
polymerization catalyst may be mixed together by various means. For
example, any conventional mixer or blender may be employed to mix
the macrocyclic polyester oligomer with the polymerization catalyst
via agitation at temperatures below the melting temperature of the
macrocyclic polyester oligomer. This process may be conducted under
an inert atmosphere such as a nitrogen atmosphere.
[0084] A solvent may also be employed to assist in the uniform
mixing of the macrocyclic polyester oligomer with the
polymerization catalyst. Various solvents can be used, and there is
no limitation with respect to the type of solvent that may be used
other than that the solvent is substantially free of water.
Illustrative examples of solvents that may be employed in the
invention include methanol, ethanol, isopropanol, acetone, methyl
ethyl ketone, benzene, toluene, o-xylene, chlorobenzene,
dichloromethane, and chloroform.
[0085] There is no limitation with respect to the amount of solvent
to be employed other than that the amount results in a uniform
mixing of the macrocyclic polyester oligomer and the polymerization
catalyst. In one embodiment, the blend of macrocyclic polyester
oligomer with the polymerization catalyst is isolated either by
direct removal of the solvent via evaporation or by precipitation
via addition of the mixture into a nonsolvent. In another
embodiment, the blend of solid ingredients is further dried under
vacuum at elevated temperatures below the melting temperature and
the polymerization temperature of the macrocyclic polyester
oligomer to remove any residual solvent
[0086] A process for preparing the blend material further having at
least one filler, or any other additional material, is generally
the same as described above, however, the characteristics of the
filler and/or additional materials must be considered. It should be
understood that the macrocyclic polyester oligomer, the
polymerization catalyst, the filler, any additional material(s)
and/or solvent, if used, may be mixed in any order or
simultaneously as long as the final composition contains the
appropriate amount of each ingredient.
[0087] It is within the scope of the invention to employ one, two
or more different fillers in preparing a blend material of
macrocyclic polyester oligomer and polymerization catalyst. Unless
specifically stated otherwise, any embodiment of a composition,
article or process that refers to filler in singular also includes
an embodiment wherein two or more different fillers are employed.
Similarly, unless stated otherwise, any embodiment of a
composition, article or process that refers to fillers in plural
also includes an embodiment wherein one filler is employed.
[0088] In one embodiment of the invention, the amount of
polymerization catalyst employed is generally about 0.01 to about
10.0 mole percent, preferably about 0.1 to about 2 mole percent,
and more preferably about 0.2 to about 0.6 mole percent based on
total moles of monomer repeat units of the macrocyclic polyester
oligomer
[0089] Although dependent on the particular composition of the
blend material, blend materials typically exhibit a shelf life
generally longer than a week, and preferably longer than a month,
and more preferably longer than a year when stored at ambient
temperature.
[0090] It is within the scope of the invention to employ one, two
or more different polymerization catalysts in preparing a blend of
macrocyclic polyester oligomer and polymerization catalyst. Unless
specifically stated otherwise, any embodiment of a composition,
article or process that refers to polymerization catalyst in
singular also includes an embodiment wherein two or more different
polymerization catalysts are employed. Similarly, unless stated
otherwise, any embodiment of a composition, article or process that
refers to polymerization catalyst in plural also includes an
embodiment wherein one polymerization catalyst is employed. Two or
more polymerization catalysts may be used to vary the rate of
polymerization and to produce polyesters with variable degrees of
branching.
[0091] IV. Polyermizing Macrocyclic Polyester Oligomers
[0092] In some aspects of the invention, various processes are
employed to polymerize a macrocyclic polyester oligomer. For many
of these processes, the unique properties of the macrocyclic
polyester oligomers make it possible to use these processes
advantageously. Generally, it was not previously contemplated that
the use of macrocyclic polyester oligomers with these processes
would in any way be advantageous.
[0093] It is not necessary that a blend material as described above
is employed in these processes, however, depending on the
application, use of a blend material may be advantageous. It is
contemplated that for processes in which a macrocyclic polyester
oligomer and a catalyst are provided, it is possible to provide
them separately. For example, a macrocylic polyester oligomer and a
catalyst can be added to a reaction vessel at different times, or
via different mechanisms. As another example, a mixture of the
macrocyclic polyester oligomer and a catalyst can be made as they
are added to a reaction vessel. It is also contemplated that the
blend material can be used to provide a macrocyclic polyester
oligomer and to provide a catalyst.
[0094] In one embodiment, a process for preparing a high molecular
weight polyester polymer includes providing a blend material having
a macrocyclic polyester oligomer and a polymerization catalyst, and
polymerizing the macrocyclic polyester oligomer. The blend material
may include a filler. The filler may also be added prior to,
during, or after the polymerization process. Any reaction vessel
may be employed that is substantially inert to the ingredients of
the blend material.
[0095] Generally, the reaction vessel is charged with the blend
material. Preferably, the macrocyclic polyester oligomer is
polymerized by heating the macrocyclic polyester oligomer to an
elevated temperature. Often the macrocyclic polyester oligomer is
heated to above its melting point so it becomes less viscous and
can be manipulated easier in processing. Subsequently, the
temperature may be maintained or increased to initiate and complete
the polymerization reaction. In one embodiment, heat is supplied to
melt the blend material at about 130.degree. C. to about
250.degree. C., preferably about 160.degree. C. to about
220.degree. C., and more preferably about 180.degree. C. to about
190.degree. C. to initiate and complete polymerization. Stirring
may be employed under an inert atmosphere in order to enhance
polymerization of the macrocyclic polyester oligomer to produce the
desired polyester polymer. In one embodiment, the polymerization is
conducted under air atmosphere. In another embodiment, the
polymerization is conducted under inert atmosphere.
[0096] Examples of polyesters produced by the processes of the
invention include poly(ethylene terephthalate), poly(1,3-propylene
terephthalate), poly(1,4-butylene terephthalate),
poly(1,4-cyclohexylenedimethylene terephthalate), poly(1,2-ethylene
2,6-naphthalenedicarboxylate) and copolyesters comprising two or
more of the above monomer repeat units.
[0097] In one aspect of the invention, articles are produced using
the blend material (with or without fillers) via injection and
rotational molding, resin film infusion, resin transfer molding,
filament winding, powder coating to create a prepreg or film, hot
melt prepreg preparation, compression molding, roll wrapping, water
slurry, and pultrusion with or in some cases without reinforcement.
The only proviso is that conditions allow for the polymerization of
the blend to form high molecular weight polyester upon heating.
Generally, most of such processes require that the resin to be
processed have a low melt viscosity; therefore, conventional
thermoplastic resins that have high melt viscosity are not suitable
for processing. However, macrocyclic polyester oligomers have low
melt viscosity.
[0098] Also, in processing conventional thermoplastic resins with
such processes, the cooling of the mold after processing is
required to solidify the melt. Demolding can occur only after such
a cooling step. This results in longer processing time and
increased energy usage. However, macrocyclic poly(1,4-butylene
terephthalate) oligomers, for instance, polymerize at a
temperature, from about 180.degree. C. to about 200.degree. C.,
that is lower than the melting point of the resulting polyester
polymer which is about 220.degree. C. In addition,
poly(1,4-butylene terephthalate) has a favorable crystallization
rate even at such temperatures. Thus, the resulting polyester
polymer crystallizes without cooling the mold allowing
polymerization and demolding to occur at the same temperature
thereby reducing processing time and energy consumption.
[0099] In applying macrocyclic polyester oligomers to the processes
described below, a fast crystallization of the resulting polyester
polymer may be desirable. Depending on the nature of the
macrocyclic polyester oligomers, the nature of the resulting
polymer, and the polymerization process employed, fast
crystallization may need to be induced by cooling the mold wherein
the polymerization process occurred. For instance, in general, high
molecular weight poly(1,4-butylene terephthalate) crystallizes
fairly rapidly even at 180.degree. C. to 200.degree. C. while, in
general, poly(ethylene terephthalate) requires cooling from such
temperatures to achieve a favorable crystallization rate. In cases
where the polyester polymers have a melting point higher than the
polymerization temperature but does not crystallize at a favorable
rate, agents, such as nucleating agents, which facilitate
crystallization may be employed. In cases where the polyester
polymers have a melting point lower than the polymerization
temperature, cooling is needed to bring about crystallization of
the resulting polyester polymer.
[0100] In one embodiment of each of the following processes
involving a polymerization of a macrocyclic polyester oligomer, no
cycling (i.e., cooling and heating) the tools (e.g., the mold
and/or other equipment) after polymerization is complete, is
conducted. In another embodiment of each of the following processes
involving a polymerization of a macrocyclic polyester oligomer,
some cooling is conducted.
[0101] The following general definitions may be helpful in
understanding the various terms and expressions used in this
specification and particularly in the processes described below.
"Wet-out" means a process to cause a physical state of good and
sustained contact between a liquid substrate and a solid substrate
such that no substantial amount of air or other gas is trapped
between the liquid substrate and the solid substrate. "Fiber" means
any material with slender, elongated structure such as polymer or
natural fibers. The material can be fiberglass, ceramic fibers,
carbon fibers or organic polymers such as aramid fibers. Fibers may
also be grouped to form a "tow" or "strand". A "tow" or "strand" is
a group of fibers together, or a bundle of fibers, which are
usually wound onto spools and may or may not be twisted. These tows
or strands can be woven or knitted to form fabrics. A "tackifier"
or "binder" is resin or glue used in small amounts to lightly hold
fibers together. A "fiber preform" is an assembly of fiber tows
and/or fabric held together in a desired shape. Generally, fiber
preform fibers are dry and may be held together with various
tackifiers. A "prepreg" is a fiber material such as carbon fiber,
glass fiber, or other fiber, that has been impregnated with a resin
material in sufficient volume as to provide the matrix of the
composite, and such that the ratio of fiber to resin is closely
controlled. The fiber configuration can be in tow form, woven or
knitted into a fabric, or in a unidirectional tape. The stickiness
that allows multiple uncured layers to stick to one another during
assembly is known as "tack". The ability of a layer of material to
be formed to a complex shape before it is processed is known as
"drape".
[0102] a. Rotational Molding
[0103] Referring to FIG. 1, rotational molding is a process for
making hollow thermoplastic articles, such as a wide variety of
articles including fluid storage tanks, tractor fenders and large
children's toys. In one aspect of the invention, rotational molding
is used to manufacture articles from a macrocyclic polyester
oligomer. Typically, the process begins by placing a macrocyclic
polyester oligomer and a polymerization catalyst in a mold 110.
After closing the mold 110, the mold is rotated about two axes 120,
130 simultaneously so that the contents roll over the intended
areas of the inside of the mold. Heat 140 is applied to melt the
macrocyclic polyester oligomer and the polymerization catalyst.
After the macrocyclic polyester oligomer and the polymerization
catalyst are melted, the rotation continues until the content
polymerizes and solidifies. The part is demolded while the tools
are hot or after some cooling of the tools. The process can then be
repeated with the same equipment to produce another thermoplastic
part. The rotation rates about the axes are often controlled so
that the orientation of the mold takes a long time to repeat. This
provides a uniform coverage inside the mold. Heat can be applied in
the form of external gas flames, but internal electrical mold
heating can also be used. One type of mold is made of aluminum with
a wall thickness of 1/4 of an inch. Fiber reinforced plastic can be
used as well.
[0104] In one embodiment of the invention, a process for
polymerizing a macrocyclic polyester oligomer includes providing a
macrocyclic polyester oligomer, providing a polymerization catalyst
(or in the case of a blend material, providing a blend material
having a macrocyclic polyester oligomer and a polymerization
catalyst), loading the macrocyclic polyester oligomer and the
polymerization catalyst (or in the case of a blend material,
loading the blend material) into a mold having a chamber, rotating
the mold along at least one axis, and heating the mold or otherwise
to cause polymerization. In one embodiment, the process also
includes the step of removing the resulting polymer while the
resulting polymer is at substantially the same temperature of the
polymerization and the resulting polymer solidifies into a solid at
the polymerization temperature.
[0105] In one embodiment, the macrocyclic polyester oligomer and
the polymerization catalyst (or the blend material) is fed into a
cool mold. In another embodiment, the macrocyclic polyester
oligomer and the polymerization catalyst (or the blend material) is
fed into a hot mold with the temperature of the mold being
substantially the same as the polymerization temperature. In one
embodiment, the mold is not cooled before the start of the next
processing round. In another embodiment, the mold temperature is
cooled before the next round of processing. In one embodiment, the
mold is rotated along one axis. In another embodiment, the mold is
rotated along two or more axes.
[0106] In one embodiment, the macrocyclic polyester oligomer
processed by rotational molding is a macrocyclic PBT oligomer. A
macrocyclic PBT oligomer has a melting point at about 180.degree.
C., which is much lower than the melting point of polymerized PBT,
which is about 220.degree. C. As a result, the polymerized PBT
solidifies and can be removed from the mold at approximately the
temperature at which polymerization is conducted.
[0107] In another embodiment, the macrocyclic polyester oligomers
are macrocyclic PBT/PET co-oligomers. Macrocyclic PBT/PET
co-oligomers have a melting point at about 180.degree. C., which is
much lower than that of the polymerized PBT/PET. Polymerized
PBT/PET melts at about 220.degree. C. to 240.degree. C. depending
on the PBT/PET ratio. As a result, the polymerized PBT/PET
crystallizes and can be removed from the mold at the temperature at
which polymerization is conducted.
[0108] In one embodiment, a filler is placed into the mold in which
it is mixed with the macrocyclic polyester oligomer and the
polymerization catalyst. In another embodiment, a filler is mixed
with the macrocyclic polyester oligomer and the polymerization
catalyst before being placed in the mold. In yet another
embodiment, a filler is part of the blend material.
[0109] b. Resin Film Infusion
[0110] Referring to FIG. 2, resin film infusion is a process for
making plastic composite articles that are predominantly flat on
one face and may have detailed features. An illustrative example of
such articles is aircraft wing skins which are typically
constructed of a composite made with carbon fiber and epoxy resin.
In one aspect of the invention, resin film infusion is used to
manufacture articles from macrocyclic polyester oligomers. A layer
or film 210 of a macrocyclic polyester oligomer containing a
polymerization catalyst is placed in a mold 220 that has a layer of
dry fiber 230. The macrocyclic polyester oligomer layer or film 210
is placed between the layer of dry fiber 230 and the mold surface
240. The mold 220 is then heated to melt the macrocyclic polyester
oligomer layer or film 210, which then infuses into the dry fiber
layer 230, usually under a force created by a vacuum 260 on the
other side of the dry fiber layer 230. A vacuum bag 270 may be used
together with a seal 280 maintained between the vacuum bag 270 and
the mold surface 240. After the completion of polymerization, the
part is either demolded hot or after some cooling of the tools.
[0111] In one embodiment, a process for polymerizing a macrocyclic
polyester oligomer includes providing a macrocyclic polyester
oligomer, providing a polymerization catalyst (or, in the case of a
blend material, providing a blend material having a macrocyclic
polyester oligomer and a polymerization catalyst), loading the
macrocyclic polyester oligomer and the polymerization catalyst (or
in the case of a blend material, loading the blend material) into a
mold having a dry layer of fibrous material to form a layer between
the dry layer of fibrous material and a surface of the mold,
heating the mold to melt the macrocyclic polyester oligomer,
forcing the macrocyclic polyester oligomer and the polymerization
catalyst to infuse into the dry layer of fibrous material, and
heating the mold or otherwise to cause polymerization of the
macrocyclic polyester oligomer. In another embodiment, the infusion
process is facilitated, for example, by a pressure generated from a
vacuum bag. The resin layer could also be between the vacuum bag
and the fiber layer. The resin layer does not have to go against
the mold. Because the resin film of the macrocyclic polyester
oligomer melts to a low viscosity liquid, infusion into a fiber is
easily accomplished. In one embodiment, the process also includes
the step of removing the resulting polymer while the resulting
polymer is at substantially the same temperature of the
polymerization and the resulting polymer solidifies into a solid at
the polymerization temperature. In one embodiment, no cooling of
the mold is conducted before demolding or before the start of the
next round of processing with the mold. In another embodiment, some
cooling of the mold is conducted before demolding or the start of
the next round of processing.
[0112] In another embodiment, a filler is placed into the mold in
which it is mixed with the macrocyclic polyester oligomer and the
polymerization catalyst. In another embodiment, a filler is mixed
with the macrocyclic polyester oligomer and the polymerization
catalyst before being placed in the mold. In yet another
embodiment, a filler is part of the blend material.
[0113] In one embodiment, a macrocyclic PBT oligomer is polymerized
using the resin film infusion processes described here.
[0114] In one embodiment, a macrocyclic polyester oligomer powder
prepreg is used instead of the fabric and resin layers. A powder
prepreg in this case is a base material, usually fibrous, that has
been impregnated with macrocyclic polyester oligomers in powder
form before they are placed in the mold. In another embodiment, a
prepreg, described in the next section, is used in a resin film
infusion process. A prepreg may be a unidirectional prepreg whereon
the impregnated content is distributed along one direction.
[0115] Typically with resin film infusion processes, if the resin
is a thermoset, additional heat is typically needed to solidify the
resin before demolding. If the resin is a conventional
thermoplastic, the material generally must be cooled to re-solidify
the resin before demolding can take place. The high viscosity of
melted conventional thermoplastic materials and poor infusion
characteristics have, in the past, made resin film infusion
processes suitable almost exclusively to thermoset. As just
described, macrocyclic polyester oligomers can be processed using a
resin film infusion process to produce a thermoplastic.
[0116] C. Prepreg Processes
[0117] In one embodiment, a unidirectional prepreg is in the form
of unidirectional prepreg tape which includes a sheet of fibers.
The sheet of fibers is held in the sheet form because the fibers
are impregnated with macrocyclic polyester oligomers that hold them
together. Two primary methods are used to make unidirectional
prepregs from macrocyclic polyester oligomers, solvent impregnation
and hot melt.
[0118] Referring to FIG. 3, a solvent impregnation method is
implemented by running fabric or fiber tow 305 through a solvent
bath 310 containing a macrocyclic polyester oligomer and a
polymerization catalyst. The concentration of macrocyclic polyester
oligomer is typically 30% by weight. The solvent is used to reduce
the viscosity, which allows easy wet-out of the fabric or fiber tow
305. The fabric or fiber tow 305, wetted with the macrocyclic
polyester oligomer, the polymerization catalyst, and the solvent,
is then transported to drying oven 315 wherein the solvent is
flashed off. The macrocyclic polyester oligomer and the
polymerization catalyst remain on the fabric or fiber tow 305. The
fabric or fiber tow 305 may be heated at temperatures and for an
amount of time that allows some or all of the solvent to flash off
in order to control tack. The amount of tack reduces as more
solvent is flashed off. Then, the paper sheet 320 is rolled
together with the fabric or fiber tow 305 to form a prepreg with
paper backing 325, completing the prepreg process.
[0119] In one embodiment, a process for impregnating a macrocyclic
polyester oligomer and a polymerization catalyst to form a prepreg
includes the steps of dissolving a macrocyclic polyester oligomer
and a polymerization catalyst (or in the case of a blend material,
dissolving a blend material having a macrocyclic polyester oligomer
and a polymerization catalyst) in a solvent to form a solution,
contacting the solution with a fibrous base material, and removing
the solvent. In another embodiment, the solvent is removed by heat.
In one embodiment, the fibrous base material is a fiber tow. In
another embodiment, a release paper backing is provided and placed
adjacent the macrocyclic polyester oligomer and the polymerization
catalyst.
[0120] In one embodiment, a macrocyclic polyester oligomer is
incorporated into a unidirectional prepreg using a solvent process.
In one embodiment, a process for impregnating a macrocyclic
polyester oligomer includes dissolving a macrocyclic polyester
oligomer and a polymerization catalyst (or in the case of a blend
material, dissolving a blend material having a macrocyclic
polyester oligomer and a polymerization catalyst), combining the
solution with a filler to form a mixture, applying the mixture to a
base material, and removing the solvent.
[0121] Referring to FIG. 4, a hot-melt method starts with a release
paper 405 that has been coated with a layer of a macrocyclic
polyester oligomer and a polymerization catalyst to a specific
thickness. The release paper 405 having the coating thereon is
stored on a roll 410. When combined with a fiber tow 415 that has
been preheated, the macrocyclic polyester oligomer and the
polymerization catalyst on the release paper 405 is brought into
contact with the fiber tow 415 and is heated by a heating block 420
to reduce viscosity of the coating. Compaction rollers 425 drive
the fiber tow 415 into the macrocyclic polyester oligomer coating
layer forming a prepreg with a paper backing which is then rolled
onto roller 430.
[0122] In one embodiment, a process for impregnating a macrocyclic
polyester oligomer and a polymerization catalyst to form a prepreg
includes the steps of providing a release base material having
thereon a macrocyclic polyester oligomer and a polymerization
catalyst (or in the case of a blend material, providing a release
base material having thereon a blend material having a macrocyclic
polyester oligomer and a polymerization catalyst) and pressing the
release base material against a fibrous material under heat. In one
embodiment, a filler is also impregnated with the macrocyclic
polyester oligomer and the polymerization catalyst. In one
embodiment, the filler is part of a blend material to be
impregnated. In one embodiment, the prepreg is made with tack. A
macrocyclic polyester oligomer containing appropriate amount of a
polymerization catalyst is thinly spread on non-stick substrate
surface and melted with instant heating. The molten macrocyclic
polyester oligomer is then rapidly cooled to quench from
crystallization, resulting in a soft pliable film that can be
removed from the substrate surface. Macrocyclic polyester oligomers
made with tack are used in many applications that are generally for
thermosetting resins. Macrocyclic polyester oligomers with tack are
processed like a thermoset while producing a thermoplastic
product.
[0123] A unidirectional prepreg tape of conventional thermoplastic
does not have tack or drape at room temperature, it must be heated
when formed, and is difficult to use. Thermally quenched
non-crystalline macrocyclic polyester oligomers are soft and sticky
at ambient temperature. Illustrative examples of such macrocyclic
polyester oligomers are macrocyclic poly(1,4-butylene
terephthalate) (PBT), poly(1,4-cyclohexylenedimethylene
terephthalate) (PCT), poly(ethylene terephthalate) (PET), and
poly(1,2-ethylene 2,6-naphthalendicarboxylate) (PEN) oligomers and
copolyester oligomers comprising two or more of the above monomer
repeat units. Such macrocyclic polyester oligomers are used in the
creation of a thermoplastic prepreg with tack and drape.
[0124] In one embodiment, a macrocyclic PBT oligomer and a
polymerization catalyst is impregnated by the processes described
here.
[0125] d. Pultrusion
[0126] Referring to FIG. 5, pultrusion is a process for making
fiber reinforced plastic composite parts and components with a
constant linear cross-section such as rods, tubes and bars stock,
whereby fiber reinforcements are combined with a resin material and
pulled through a heated die. The fiber-reinforced composite parts
exit the die in the desired shape. In one aspect of the invention,
pultrusion processes are used to manufacture articles from
macrocyclic polyester oligomers. A dry fiber tow or fabric 510 is
first pulled by puller 550 through the liquid resin bath 520 to
apply the macrocyclic polyester oligomer and the polymerization
catalyst 530, and then is pulled by a puller 550 into the heated
die 540 to polymerize the macrocyclic polyester oligomer, and to
form the desired shape and to solidify. The viscosity of the liquid
resin is relatively low, approximately 100's of centipoise at room
temperature, and easily wets and impregnates the fiber
material.
[0127] Variations of the above process include pumping the
macrocyclic polyester oligomer and the polymerization catalyst into
the die to completely eliminate the liquid resin bath. This process
is sometimes called "Continuous Resin Transfer Molding" (CRTM). As
to the fiber, it can be carbon, glass, aramid, or other fibrous
materials.
[0128] In one embodiment of the invention, a pultrusion process is
used to polymerize macrocyclic polyester oligomers for the
manufacture of a variety of articles. Such a process includes
providing a macrocyclic polyester oligomer, providing a
polymerization catalyst (or in the case of a blend material,
providing a blend material having a macrocyclic polyester oligomer
and a polymerization catalyst), pulling a fibrous strand into an
elongated die, moving the macrocyclic polyester oligomer and the
polymerization catalyst (or in the case of a blend material, moving
the blend material) into the die thereby causing contact with and
around the fibrous strand, heating to cause polymerization of the
macrocyclic polyester oligomer forming high molecular weight
polyester resin matrix around the fibrous strand, and pulling the
polyester matrix into an exit portion of the die having a desired
cross section thereby forming a rigid article. When the die is not
heated to the melting point of the resulting polyester resin matrix
and the crystallization rate of the resulting polymer is favorable
at the polymerization temperature, no cooling is necessary to allow
the solidification of the polyester resin matrix. In one
embodiment, no cooling of the tools is conducted. In another
embodiment, some cooling is conducted. In one embodiment, a blend
material is injected directly into the pultrusion die. In one
embodiment, a powder impregnation process, such as electrostatic
powder coating, is used to combine the blend material with fiber
strands prior to its introduction into the pultrusion die. In one
embodiment, the process of combining the blend material and fiber
strands is done off-line before pultrusion, and wound onto spools.
In another embodiment, combination is done inline in place of the
resin bath.
[0129] In another embodiment, the blend material in powder form is
fed directly into the pultrusion die having a melting and
impregnation zone. In another embodiment, the blend material is
continuously melted outside the die, and pumped into the die in
liquid form. In one embodiment, macrocyclic PBT oligomer is
polymerized using the pultrusion processes described here.
[0130] Referring to FIG. 6, in one embodiment, macrocyclic
polyester oligomers are used in a pultrusion process wherein the
blend material is continuously melted outside the die and pumped
into the die in liquid form. The blend material powder 610 is fed
into hopper 620. An extruder 630 which has a barrel chamber with a
rotating worm screw forces the powder into a heated zone 640 which
is typically heated by an electricity, steam or oil system 650. The
melted blend material exits the end of the extruder 660 and enters
the pultrusion die. This process may also be adopted to employ a
macrocyclic polyester oligomer and a polymerization catalyst not in
the form of a blend material.
[0131] Referring to FIG. 7, in another embodiment of the invention,
the blend material is continuously melted outside the die and
pumped into the die in liquid form. A piston 710 is placed inside
cool cylinder 720 and is connected to and driven by a ram 730. The
blend material 735 is placed inside the cool cylinder between the
front surface 740 of the piston 710 and the back surface 750 of the
hot melting block 760. A hole in the melting block 765 allows the
blend material to be pushed through the melting block 760. The hot
melting block is typically heated by an electricity, steam or oil
heating system 775. As the piston is pushed up, the blend material
becomes melted as it comes into contact with the melting block 760,
forms a melted region 780, and travels through a hole 765 in the
melting block, out the exit from the melting head 790 and into the
mold or pultrusion die. This process may also be adopted to employ
a macrocyclic polyester oligomer and a polymerization catalyst not
in the form of a blend material.
[0132] Generally, it is difficult to use conventional thermoplastic
resins in the above processes because conventional thermoplastic
resins are difficult to process due to their high melt viscosity.
Macrocyclic polyester oligomers, however, melt to a low viscosity
liquid. Low viscosity makes it easy to wet out fibers, like
thermoset resins. Macrocyclic polyester oligomers can polymerize to
high molecular weight thermoplastics. An additional advantage of
using PBT-based macrocyclic polyester oligomers is that they will
melt, wet out a fiber, polymerize, and crysallize or solidify all
at a constant temperature, in the range of about 180.degree. C. to
about 200.degree. C. This reduces and even eliminates the need to
cool the exit end of the pultrusion die, allowing the shortening of
the die and/or the increase of the pull speed.
[0133] e. Resin Transfer Molding
[0134] Referring to FIG. 8, resin transfer molding is a process for
making plastic composite articles in a variety of shapes and sizes,
often with a smooth surface finish and requiring little or no
additional trimming or machining, such as automotive body panels
and chassis components, bicycle forks, and tennis rackets. In one
aspect of the invention, resin transfer molding processes are used
to manufacture articles from macrocyclic polyester oligomers.
Generally, resin transfer molding begins with a fiber preform 810
that is close to the final shape of the part. The preform 810 is
placed in a mold 820 of the desired final shape, and the mold is
closed. A mixture of macrocyclic polyester oligomer and a
polymerization catalyst is melted to a melt 830 that is then pumped
in. The melt wets out the fiber preform 810 and fills any remaining
volume 850. Once the resulting polyester thermoplastic polymer
solidifies the part is demolded. Depending on the nature of the
macrocyclic polyester oligomers, the nature of the resulting
polyester polymer, and the polymerization process, a cooling step
may or may not be needed to bring about crystallization.
[0135] The melt 830 is usually injected slowly so that it wicks
into the fiber of the fiber preform 810. Vacuum applied to the vent
870 before and during processing can help eliminate trapped air.
The vent 870 can also be sealed and the mold pressurized with resin
to eliminate voids. Also, the mold can be heated to maintain the
low viscosity of the resin and to effect polymerization. Resin
transfer molding processes described here may be used to
manufacture articles from macrocyclic polyester oligomers.
[0136] In one embodiment of the invention, a process for
polymerizing a macrocyclic polyester oligomer includes providing a
macrocyclic polyester oligomer, providing a polymerization catalyst
(or in the case of a blend material, providing a blend material
having a macrocyclic polyester oligomer and a polymerization
catalyst), loading the macrocyclic polyester oligomer and the
polymerization catalyst (or loading the blend material) into the
mold having the fibrous preform therein, heating the mold to melt
the macrocyclic polyester oligomer, forcing the macrocyclic
polyester oligomer and the polymerization catalyst into the fibrous
preform, and heating the mold to cause polymerization of the
macrocyclic polyester oligomer. In one embodiment, the process also
includes the step of removing the resulting polymer while the
resulting polymer is at substantially the same temperature of the
polymerization and the resulting polymer solidifies into a solid at
the polymerization temperature. In one embodiment, no cooling of
the mold is conducted before demolding or before the start of the
next round of processing with the mold. In another embodiment, some
cooling of the mold is conducted before demolding or the start of
the next round of processing. In one embodiment, a macrocyclic PBT
oligomer is polymerized using the resin film infusion processes
described here. In another embodiment, no fibrous preform is used.
Resin transfer molding can be done without a preform. Such a
process is referred to as casting.
[0137] In another embodiment, a filler is placed into the mold in
which it is mixed with the macrocyclic polyester oligomer and the
polymerization catalyst. In another embodiment, a filler is mixed
with the macrocyclic polyester oligomer and the polymerization
catalyst before being placed in the mold. In yet another
embodiment, a filler is part of the blend material as described
above.
[0138] Because macrocyclic polyester oligomers melt to a low
viscosity liquid, infusion into fibers is easily accomplished.
After polymerization is complete, the part is demolded with or
without cooling depending on the macrocyclic polyester oligomer
employed, the nature of the resulting polyester polymer, and the
polymerization process. Furthermore, resin transfer molding
generally uses only thermosetting resins, such as epoxy,
unsaturated polyester, and phenolic resins. In one embodiment,
thermoplastic articles are manufactured from macrocyclic polyester
oligomers using the resin transfer molding processes.
[0139] f. Filament Winding
[0140] Referring to FIG. 9, filament winding is a process for
making plastic composite parts that are hollow and require high
strength and light weight such as tubes, compressed air tanks,
fluid storage tanks, and automotive drive shafts. In one aspect of
the invention, filament winding processes are used to manufacture
articles from macrocyclic polyester oligomers. Generally, the
process involves the winding of fibers 910 onto a mandrel 920. One
embodiment for loading a macrocyclic polyester oligomer and a
polymerization catalyst is to simply brush them onto the mandrel
920 and wind the fibers 910 as the mandrel 920 rotates. Another
embodiment is to use a resin bath, such as a dip tank or rollers,
to impregnate the fibers 910 somewhere between the fiber spool 940
and the mandrel 920. Another embodiment is using a prepreg fiber
tow with the macrocyclic polyester oligomer and the polymerization
catalyst in the tow to begin with. In another embodiment, the
fibers are wound dry, followed by vacuum infusing with resin.
[0141] A macrocyclic polyester oligomers and a polymerization
catalyst can be used in the form of a prepreg. Flat fiber bundle
impregnated with a macrocyclic polyester oligomer and a
polymerization catalyst is applied with heat and pressure at the
location where the tape first touches the part. In one embodiment,
the part is cool, and only the local vicinity around the tape
contact is heated. A roller is typically used to apply the pressure
to press the tape into the part and consolidate the material. The
part can be wound cool. It can be removed from the mandrel
immediately after winding. Some post heating and consolidation can
be done to improve the properties of the part. In one embodiment,
the blend material is pre-impregnated in a fiber tow.
[0142] In one embodiment, a process for polymerizing a macrocyclic
polyester oligomer includes providing a macrocyclic polyester
oligomer, providing a polymerization catalyst (or in the case of a
blend material, providing a blend material having a macrocyclic
polyester oligomer and a polymerization catalyst), heating to cause
the macrocyclic polyester oligomer to melt, contacting the molten
macrocyclic polyester oligomer and the polymerization catalyst with
a fibrous strand, winding the fibrous strand onto a mandrel, and
heating the macrocyclic polyester oligomer to cause its
polymerization. In one embodiment, the process also includes the
step of removing the resulting polymer while the resulting polymer
is at substantially the same temperature of the polymerization and
the resulting polymer solidifies into a solid at the polymerization
temperature. In one embodiment, no cooling of the mold is conducted
before demolding or before the start of the next round of
processing with the mold. In another embodiment, some cooling of
the mold is conducted before demolding or the start of the next
round of processing. In one embodiment, a macrocyclic PBT oligomer
is polymerized using the resin film infusion processes described
here.
[0143] In another embodiment, a filler is placed into the mold in
which the filler is mixed with the macrocyclic polyester oligomer
and the polymerization catalyst. In another embodiment, a filler is
mixed with the macrocyclic polyester oligomer and the
polymerization catalyst before being placed in the mold. In yet
another embodiment, a filler is part of the blend material.
[0144] g. Compression Molding
[0145] Referring to FIG. 10, compression molding, stamping, or
pressing, is a process for making plastic composite parts that are
thin and generally flat with mild features and contours such as
truck and auto body panels, bumper beams, various trays and machine
housings. In one aspect of the invention, compression molding is
used to manufacture articles from macrocyclic polyester oligomers.
A press 1010 has a press frame 1020. Within the press 1010 are top
die 1030 and lower die 1040. A prepreg or sheet molding compound
(SMC) 1050 is placed between the top die 1030 and the lower die
1040 within the press 1010. The prepreg or molding compound 1050
typically is heated and stamped under heat and pressure and then
removed. A SMC or sheet molding compound refers to a highly filled
compound with a resin binder that is placed in a hot matched metal
tool and compressed to evenly fill the mold and solidify into a net
or near net shape part.
[0146] In one embodiment of the invention, a macrocyclic polyester
oligomer is polymerized using compression molding. In one
embodiment, a process for polymerizing a macrocyclic polyester
oligomer includes providing a macrocyclic polyester oligomer,
providing a polymerization catalyst (or in the case of a blend
material, providing a blend material having a macrocyclic polyester
oligomer and a polymerization catalyst), providing a fibrous base
material, heating to cause the macrocyclic polyester oligomer to
melt, and loading the molten macrocyclic polyester oligomer and the
polymerization catalyst onto the fibrous base material, pressing
the dies of the mold, and heating or otherwise to cause
polymerization of the macrocyclic polyester oligomer. In one
embodiment, the process also includes the step of removing the
resulting polymer while the resulting polymer is at substantially
the same temperature of the polymerization and the resulting
polymer solidifies into a solid at the polymerization temperature.
In one embodiment, no cooling of the mold is conducted before
demolding or before the start of the next round of processing with
the mold. In another embodiment, some cooling of the mold is
conducted before demolding or the start of the next round of
processing.
[0147] In another embodiment, a filler is placed into the mold in
which it is mixed with the macrocyclic polyester oligomer and the
polymerization catalyst. In another embodiment, a filler is mixed
with the macrocyclic polyester oligomer and the polymerization
catalyst before being placed in the mold. In yet another
embodiment, a filler is part of the blend material.
[0148] In one embodiment, a macrocyclic PBT oligomer is polymerized
using the resin film infusion processes described here. In the case
of PBT, the cycle time can be greatly reduced because the
processing temperature is below the melting point of the resulting
PBT polymer. In one embodiment, macrocyclic polyester oligomers are
used to make high quality thermoplastic composite parts with powder
coated fabric.
[0149] h. Roll Wrapping
[0150] Referring to FIG. 11, roll wrapping is a process for making
tubular articles such as composite golf shafts, windsurfing masts
and various tie rods for aircraft. In one aspect of the invention,
roll wrapping processes are used to manufacture articles from
macrocyclic polyester oligomers. The tubular articles can be round,
elliptical, or even rectangular cross sections. They can be tapered
as well. A mandrel 1110 that serves as the forming core is placed
on the edge 1120 of a layer of prepreg sheet 1130. The prepreg
sheet 1130 is rolled onto the mandrel 1110. Proper tack on the
prepreg sheet 1130 allows the mandrel 1110 to pick up the prepreg
sheet 1130 to begin the wrapping process, and to allow the layers
to adhere to one another. The fiber orientation 1140 may be
alternated in a sequence of layers, so as to distribute strength as
desired. The assembly can be wrapped tightly in shrink-wrap tape
that shrinks when heated to apply pressure to the composite as it
consolidates. In one embodiment, the assembly is heated to cause
polymerization. In one embodiment, a macrocyclic polyester oligomer
and a polymerization catalyst is impregnated in a sheet of
reinforcing fibers to form the prepreg. The tack allows multiple
uncured layers to stick to one another during assembly, and the
drape allows the uncured sheet to be easily contoured to the shape
of the component. Illustrative examples of such macrocyclic
polyester oligomers are macrocyclic poly(1,4-butylene
terephthalate) (PBT), poly(1,3-propylene terephthalate) (PPT),
poly(1,4-cyclohexylenedimethylene terephthalate) (PCT),
poly(ethylene terephthalate) (PET), and poly(1,2-ethylene
2,6-naphthalendicarboxylate) (PEN) oligomers and copolyester
oligomers comprising two or more of the above monomer repeat
units.
[0151] In one embodiment, a process for polymerizing a macrocyclic
polyester oligomer includes rolling onto a mandrel a base material
having thereon pre-impregnated a macrocyclic polyester oligomer and
a polymerization catalyst (or in the case of a blend material, a
blend material having a macrocyclic polyester oligomer and a
polymerization catalyst), and heating or otherwise to cause
polymerization of the macrocyclic polyester-oligomer. In one
embodiment, the blend material as described above is impregnated in
a unidirectional prepreg and is processed by a roll wrapping
process. In one embodiment, the process also includes the step of
removing the resulting polymer while the resulting polymer is at
substantially the same temperature of the polymerization and the
resulting polymer solidifies into a solid at the polymerization
temperature. In one embodiment, no cooling of the mold is conducted
before demolding or before the start of the next round of
processing with the mold. In another embodiment, some cooling of
the mold is conducted before demolding or the start of the next
round of processing. In one embodiment, a macrocyclic
poly(1,4-butylene terephthalate) oligomer is polymerized using the
resin film infusion processes described here.
[0152] In another embodiment, a filler is also pre-impregnated. In
another embodiment, a filler is mixed with the macrocyclic
polyester oligomer and the polymerization catalyst before being
impregnated onto the base material. In yet another embodiment, a
filler is part of the blend material having a macrocyclic polyester
oligomer and a polymerization catalyst.
[0153] i. Powder Coating
[0154] Another type of prepreg is powder coating. Powder coatings
are done through electrostatic or other processes. Referring to
FIG. 12, an electrostatic powder coating involves placing a powder
1205 in a chamber 1210 that has tiny holes 1215 in the bottom 1220
that air (or other gases) are forced through. As the gas passes
through the powder it begins to bubble and flow like a fluid; this
is known as a fluidized bed 1225. The powder particles in the
fluidized bed 1225 can then be charged electrostatically forming
charged resin particles 1227 and will adhere electrostatically,
upon heating at a heating zone 1229, to a solid substrate that
passes through the charged fluidized powder, such as a fiber tow or
fabric 1230. The fiber tow or fabric is then brought to roll onto a
roller 1240.
[0155] In another embodiment, charged powder particles are sprayed
through a nozzle. The powder particles adhere electrostatically to
the sold substrate used to receive them. In one embodiment, charged
powder particles are sprayed using an electrostatic powder spraying
technique. In one embodiment, the powder is stored in a reservoir
with caking being prevented by slow stirring with an agitator. In
another embodiment, air fluidization of the bed is used as an
alternative to mechanical stirring. The powder is conveyed to the
electrostatic spray head by air motion. In one embodiment, the
spray head is fastened onto a gun-like holder for convenience of
operation. An orifice is fitted onto the spray head. Before the
powder particles leave the orifice, they are electrostatically
charged by internal electrodes connected to a high-tension
generator. The target substrate to be sprayed with the powder is
attached to an electrically grounded holder. The powder is
projected towards the target by the flow of air. The target is
electrically grounded so that the powder particles will adhere
during subsequent operations where the sprayed sheets must be
handled. The thickness of the powder layer laid down by the
electrostatic spraying technique is primarily a function of the
total charge of powder deposited on the target, which in turn is a
function of the voltage applied.
[0156] In one embodiment, powder coating is used to deposit a
uniform coating of a powder material onto a receiving substrate.
Illustrative examples of receiving substrates include paper,
metals, plastics, carbon, glass, and aramid fibers. The receiving
substrate is usually moving in a continuous process. The powder is
heated or treated in other ways to make the powder adhere to or
soak into the receiving substrate. Thermoset resin powders are
currently applied to a variety of fibrous materials to make
prepregs or coatings for paper or metals. Thermoplastic powders are
used to create prepregs in an attempt to get a better connection
between the reinforcing fibers and thermoplastic matrix. Still,
even powder coated thermoplastic prepregs are difficult to use
because conventional thermoplastic materials have high melt
viscosity and do not wet out fibers well and have long heat up and
cool down cycles when making parts. Thus, conventional
thermoplastic materials are difficult to use to produce high
quality composites.
[0157] In one embodiment, a blend material containing a macrocyclic
polyester oligomer and a polymerization catalyst is used in a
powder coating system, for example, in an electrostatic powder
coating process. The macrocyclic polyester oligomer is slightly
melted to adhere to the fiber and used as a prepreg in an uncured
state. Such a prepreg is then processed under heat and pressure to
allow the resin to flow and polymerize to produce high quality
composites with good surface finish and fiber wet out. The low melt
viscosity of macrocyclic polyester oligomers make them process like
a thermoset although they can produce thermoplastics.
[0158] j. Water Slurry Process
[0159] Preparation of prepregs from solid polymer precursors and
substrate fibers can be conducted by a number of methods as
mentioned above. Often, the impregnation process needs to be
conducted under a limited time/temperature process window to avoid
premature curing of the resin. While the use of organic solvents
allows a process to be performed under a wider ranges of time and
temperature, the cost associated with solvent recovery and
environmental control may be problematic.
[0160] An aqueous suspension or slurry of polymers or
polymer-precursors can be used to coat fiber substrates to prepare
pre-impregnated sheets for production of fiber-reinforced
composites. Many vinyl polymers are available in aqueous forms
produced by emulsion or suspension polymerization. However, such
aqueous systems are generally not available for polycondensation
polymers and their precursors. Typically, when a solid powder of a
macrocyclic polyester oligomer is combined with water, it does not
mix well because of a large difference in surface energy between
the solid particles and water. The addition of a water-miscible
organic solvent such as methanol, ethanol, iso-propanol, acetone,
etc., can help the macrocyclic polyester oligomer or the
polymerization catalyst to dissolve. This may, however, result in
the generation of environmentally undesirable volatile organic
compounds (VOCs). On the other hand, use of aqueous suspension of
the resin is inherently low cost and avoids the use of VOCs.
Macrocyclic polyester oligomers such as macrocyclic
poly(1,4-butylene terephthalate) oligomer (macrocyclic PBT
oligomer) can be prepared into a stable aqueous mixture or, more
preferably, a suspension with the aid of a trace amount of various
surfactants.
[0161] As used here, a "suspension" means a fluid containing
homogeneously suspended fine particles, depending on the physical
appearance such as thickness it may also be called a slurry or
simply a mixture. A "slurry" means a fluid containing fine powders
suspended with the help of surfactants. A "mixture" means a fluid
containing liquid mixed with fine powders.
[0162] Making a Water Suspension or Slurry
[0163] The water slurry process can be used to manufacture articles
from macrocyclic polyester oligomers. In one embodiment, a process
for preparing a suspension of a macrocyclic polyester oligomer and
a polymerization catalyst includes contacting the macrocyclic
polyester oligomer and the polymerization catalyst with water and a
surfactant and mixing the macrocyclic polyester oligomer and the
polymerization catalyst with water and the surfactant thereby
producing a suspension.
[0164] The step of mixing may be accomplished by any means so long
as the resulting mixture is a suspension. Any physical mixing
procedures that achieve a suspension may be employed. Therefore,
conventional means of mixing, for example, mechanical agitation,
sonication, and continuous circulation by pumping, may be employed.
Such physical mixing may be facilitated by the addition of
chemicals. Other illustrative examples of such processes include
milling, solvent process followed by evaporation, etc. Solvents
other than water may be added to facilitate the mixing, further
processing, or both. In one embodiment, a solvent other than water
is used to produce a suspension of macrocyclic polyester oligomers.
For example, an organic solvent such as methylene chloride or ethyl
alcohol may be employed. However, as mentioned above, this may
result in the generation of VOCs. In a preferred embodiment, no
solvent other than water is employed to produce a suspension of the
macrocyclic polyester oligomer and the polymerization catalyst in
water. Furthermore, the mixture may contain additional components
such as a filler and other additives. Illustrative additives
include colorants, pigments, filler, reinforcing fibers, magnetic
materials, anti-oxidants, UV stabilizers, plasticizers,
fire-retardants, lubricants, mold releases, etc.
[0165] In one embodiment, a small amount of a nonvolatile
surfactant is employed to facilitate suspension formation and to
increase suspension stability. In one embodiment, less than 2
weight percent of surfactant is employed. In another embodiment,
less than 1 weight percent of surfactant is employed. In another
embodiment, less than 0.05 weight percent of surfactant is
employed. Commercially available surfactants are typically not
volatile. The quantity that is required to facilitate suspension
formation may be negligible in causing environmental effect. In the
presence of a surfactant, wetting of solid powder is greatly
facilitated. Typically, the resulting suspension is more stable,
avoiding rapid settlement of the solid on standing. In one
embodiment, the suspension is produced by milling a macrocyclic
polyester oligomer and a polymerization catalyst in the presence of
water and a surfactant
[0166] Any surfactant that facilitates aqueous suspension formation
and does not adversely interfere with the polymerization and the
resulting polymerization products may be employed. In one
embodiment, only one surfactant is employed. In another embodiment,
two or more surfactants are employed. In one embodiment, a nonionic
surfactant, such as, polyethylene glycol monoalkyl ether, is
employed. In another embodiment, an ionic surfactant is employed.
Ionic surfactants provide for added stability of the suspension by
introducing surface electrical charges on dispersed solid
particles. In one embodiment, an anionic surfactant is employed.
Illustrative examples of anionic surfactants include sodium
dodecylbenzenesulfonate, which is a common laundry detergent
component, and sodium dodecyl sulfate. In another embodiment, a
cationic surfactant is employed. Illustrative examples of cationic
surfactants include dodecylpyridinium chloride,
dodecyltrimethylammonium bromide, dodecyltriphenylphosphonium
bromide, coco and tallow-based quaternary ammonium salts, and
1-octadecyl-3-methylimidazolinium bromide. In one embodiment, a
surfactant that carries both a positive and a negative charge in
the same molecule is employed. In one embodiment, a surfactant
containing glycerin and sugar moieties as a polar group is
employed. Surfactants containing glycerin and sugar moieties as a
polar group may be advantageously employed to introduce branching
and cross-linking in the final polymer.
[0167] The stability of suspensions depends on factors including
particle size, concentration of solid, concentration of surfactant,
etc. Typically, the smaller the particle size, the more stable is
the resulting suspension. In one embodiment, a process for
achieving small particle suspension is to mill the macrocyclic
polyester oligomer with water and a surfactant. One advantage of
this process is that it eliminates the potential problem of
handling fine particle dust.
[0168] Certain polymerization catalysts, including many tin
catalysts, pre-inoculated with the macrocyclic polyester oligomer
were essentially not affected despite the presence of water and the
surfactant during the suspension forming process. As described
below, such catalysts are effective in catalyzing polymerization
after the removal of water.
[0169] Prepreg Formation and Polymerization of MPOs
[0170] One embodiment of a prepreg formation process is depicted in
FIG. 13. Fibers 1310 are released from the fiber rolls 1320 and are
arranged into desired width, usually that of the prepreg to be
produced. The fibers 1310 are then pulled into a bath 1330 that
contains a water suspension or slurry 1340 of a macrocyclic
polyester oligomer, a polymerization catalyst, and a surfactant,
with or without additional filler or solvent. The fibers 1310 then
are pulled into a drying oven 1350 wherein water is dried off. The
fibers 1310 are then pulled into a fuse die 1360 that is heated to
melt the macrocyclic polyester oligomer onto the fibers 1310.
Depending on the die temperature and the rest time of the fibers
1310 in the fuse die 1360, the macrocyclic polyester oligomer may
polymerize in the fuse die 1360. The fibers 1310 then go into a
chill die 1370 to cool down. The prepreg is collected onto a drum
1380. The temperatures and hold times can be configured such that
the MPOs fully or partially polymerize in the fuse die, or they can
be polymerized later.
[0171] FIG. 14 shows another embodiment of a process that may be
employed to make prepregs of a macrocyclic polyester oligomer, to
polymerize a macrocyclic polyester oligomer, or both. Generally,
the process involves a suspension 1410 of water, a macrocyclic
polyester oligomer, a polymerization catalyst, and a surfactant,
with or without additional filler or solvent. The suspension is
applied through a funnel 1415 to a base material 1420 to form a
layer 1430 of the mixture on the base material 1420. The layer 1430
of the suspension is heated to remove water from the suspension.
Once dry, the remaining suspension is then pressed into a desired
form between belts 1440 run by rollers 1450. The resulting prepreg
may be left un-polymerized and partially consolidated or may be
fully polymerized and consolidated (or some combination) depending
on whether additional heating is applied after the drying step to
cause polymerization of the macrocyclic polyester oligomer.
[0172] In one embodiment, a process for impregnating macrocyclic
polyester oligomers for polymerization includes providing a
suspension of a macrocyclic polyester oligomer and a polymerization
catalyst in water, applying the suspension to a base material,
drying the applied suspension to remove water, and pressing the
dried applied suspension to a desired form.
[0173] The step of providing a suspension of a macrocyclic
polyester oligomer and a polymerization catalyst in water is
discussed above.
[0174] Applying the suspension to a base material may be
accomplished by any means so long as the suspension contacts a
receiving base material and forms thereon a layer of the suspension
of a desired shape and thickness. Depending on the application, the
thickness and/or shape of the layer of the applied suspension may
not be important and, therefore, not monitored or controlled.
Illustrative examples of methods for applying the suspension
include dropping the suspension through a funnel with an
appropriately sized and shaped opening and the use of a container
that can be tilted or otherwise causing its content to spill over
to the receiving base material. If it is useful to closely monitor
and control the shape, thickness, and features of the resulted
layer, additional devices may be included in the equipment to
provide such monitoring or control.
[0175] The receiving base material may or may not become, after the
water slurry process, part of the resulting prepreg or the
partially or completely polymerized product. The base material may
be a sheet of a polymer film or a paper coated with polymer film.
The base material may be the surface of a portion of the processing
equipment itself. The base material, if not to become a part of the
prepreg or the polymerized product, may be removed after the step
of applying the suspension and before the end of the water slurry
process. Furthermore, the base material may include raised
boundaries that help to contain the suspension and/or to achieve a
certain shape, thickness, or features.
[0176] After applying the suspension to a base material, the
applied suspension may be dried by any method so long as it results
in the removal of water from the applied suspension. Illustrative
examples of the methods for drying the applied suspension include
heating, drying by blowing or bubbling a hot gas through or over
the suspension, drying through a vacuum, or a combination of all or
some of these or other methods. A component (other than water) of
the applied suspension (e.g., a solvent such as ethyl alcohol) may
be removed before further processing. The method used for removing
water may be helpful or even sufficient in removing certain
solvents. Thus, an additional step may or may not be needed.
Depending on the nature of the component(s) to be removed, a
removal step may be carried out before, during, or after the step
of applying the suspension. As indicated above, VOCs are preferably
avoided.
[0177] Pressing may be accomplished by any means so long as the
desired form results. A desired form may include certain shape,
thickness, and features. Thus, vacuum forming, double rolling,
and/or a die may be used in shaping the product into the desired
form. In applications in which polymerization is carried out,
pressing may be conducted before, during, or after polymerization.
Also, pressing may or may not apply to the base material depending
on the application. Similarly, the base material, if it is to be
removed, may be removed before, during, or after pressing.
Furthermore, pressing may not be needed in certain applications
where the form of the prepreg or polymerized product need not be
controlled or may be achieved by the other steps of the water
slurry process.
[0178] Depending on the application, immediate polymerization of
the macrocyclic polyester oligomer may or may not be desired. If it
is desired, polymerization may be achieved by heating the applied
suspension to a temperature sufficient to cause polymerization of
the macrocyclic polyester oligomer. In one embodiment, heating is
not employed and drying is achieved by other methods with no
polymerization resulting from the drying step. In another
embodiment, heating is employed to achieve drying but not to cause
polymerization. In another embodiment, heating results in drying
the suspension and partial polymerization of the macrocyclic
polyester oligomer. In yet another embodiment, heating results in
complete polymerization of the macrocyclic polyester oligomer.
[0179] In one embodiment, a double belt press system is employed in
preparing prepregs from a macrocyclic polyester oligomer and a
polymerization catalyst, with or without additional fillers.
Referring to FIG. 14 again, the layer 1430 comprising a macrocyclic
polyester oligomer and a polymerization catalyst, with or without
additional fillers, is pressed between belts 1440 run by rollers
1450. The belts 1440 move with the layer 1430 while the layer 1430
is being pressed, heated, or both. Therefore, the temperature and
period of heating may be configured such that the layer 1430 is
fully polymerized, partially polymerized, or not polymerized.
Similarly, the temperature and period of heating or cooling may be
configured to achieve full or partial consolidation. The heat
history may include any combination of heating step(s) and cooling
step(s) in order to achieve the desired heat history. The material
of layer 1430 may be a melt or a solid or a combination of the two
along the way of the double belt press depending on the specific
configurations of the temperature, the timing, and the
pressure.
[0180] While FIG. 14 shows a double belt press system in the
context of the water slurry process, applicability of the double
belt press system is not limited to the water slurry process. The
double belt press system can be used to prepare prepregs from
macrocyclic polyester oligomers alone or in combination with other
processes described herein to achieve the desirable prepregs.
[0181] In one embodiment, the polymerization catalyst present in
the suspension is from 0.01 to 10.0 mole percent of the structural
repeat units of the macrocyclic polyester oligomer. The
polymerization catalysts that may be employed are as discussed
above. In one embodiment, the process includes the additional step
of heating the dried applied suspension to cause polymerization of
the macrocyclic polyester oligomer. In one embodiment, a suspension
of a macrocyclic polyester oligomer and a polymerization catalyst
in water is provided using the process for making a water
suspension or slurry described above.
[0182] A cooling step may or may not be needed depending on the
application. In cases where cooling is not necessary, such as where
drying is accomplished by methods other than heating and where no
polymerization is carried out, the prepreg or product can be
removed or demolded from the equipment soon after the water slurry
process. If cooling is necessary, demolding can be carried out
after the desired temperature has been achieved.
[0183] In one embodiment, the material processed by the above
process includes a blend material. In one embodiment, a blend
material containing a macrocyclic polyester oligomer and a
polymerization catalyst is mixed with water and processed by a
water slurry process. In one embodiment, the blend material further
contains a filler.
[0184] In one embodiment, a macrocyclic polyester oligomer
composition includes a macrocyclic polyester oligomer, a
polymerization catalyst, and water. In one embodiment, the
macrocyclic polyester oligomer composition further includes a
surfactant. In one embodiment, the macrocyclic polyester oligomer
composition further includes a filler and other additives such as
pigments, mold releases and stabilizers. In one embodiment, a
polyester polymer composite is prepared by drying the macrocyclic
polyester oligomer composition followed by polymerization of the
macrocyclic polyester oligomer.
[0185] In one embodiment, a process for impregnating a macrocyclic
polyester oligomer for polymerization and for polymerizing a
macrocyclic polyester oligomer includes mixing a blend material
comprising a macrocyclic polyester oligomer and a polymerization
catalyst with water with or without a surfactant to form a mixture,
applying the mixture to a base material, drying the mixture to
remove water, and pressing the dried mixture to form a prepreg.
[0186] In one embodiment, the blend material further includes a
filler. In one embodiment, a polyester polymer composite is
prepared by polymerizing a macrocyclic polyester oligomer according
to the above process. In one embodiment, an article of manufacture
is produced by the above process.
[0187] For certain applications, it may be desirable to form a
suspension that can last for a long period of time without any
components precipitating out of the suspension before the step of
applying the mixture. For other applications, a suspension may be
formed and substantial uniformity within the suspension kept by
agitation and/or stirring before and during the step of applying
the mixture.
[0188] In order to properly carry out the water slurry process and
other processes described above, grinding may be necessary to
reduce macrocyclic polyester oligomers into a powder form.
Typically, macrocyclic polyester oligomers have a low molecular
weight and can be ground into fine powder easily at ambient
temperature thereby reducing the cost of material. Conventional
thermoplastics like nylon and polypropylene are not as easy to
grind at ambient temperature and need to be cooled or frozen.
Certain conventional thermoplastics require very low (cryogenic)
temperatures to make grinding possible thereby dramatically
increasing the cost of material.
[0189] The success of a water slurry process in prepreg formation
and polymerization of macrocyclic polyester oligomers was
unexpected partly because the presence of water, in general,
disrupts and can even entirely prevent the polymerization process
from starting and progressing. Once the water is removed by drying,
however, the polymerization process can take place uninterrupted.
The water slurry process thus provides an effective and relatively
inexpensive method for preparing prepreg and polymer from
macrocyclic polyester oligomers.
V. EXAMPLES
[0190] The following examples are provided to further illustrate
and to facilitate the understanding of the invention. These
specific examples are intended to be illustrative of the invention.
The products obtained from these examples may be confirmed by
conventional techniques such as proton and carbon-13 nuclear
magnetic resonance spectroscopy, mass spectroscopy, infrared
spectroscopy, differential scanning calorimetry and gel permeation
chromatography analyses.
Example A
[0191] The macrocyclic polyester oligomers used in the following
example are macrocyclic copolyester oligomers with 95.0 mol % of
PBT and 5.0 mol % of PET. The macrocyclic copolyester oligomers
were prepared by heating a mixture of copolyester linears, organic
solvents, such as o-xylene and o-dichlorobenzene, which are
substantially free of oxygen and water, and tin or titanium
compounds as transesterification catalysts.
[0192] A clean stainless steel reactor equipped with a magnetically
coupled stirrer and heater with controls was charged with 4800 ml
(4176 grams) of o-xylene, 59.2 grams (0.269 moles) of PBT pellets
and 2.72 grams (0.0142 moles) of PET pellets to produce a 0.06 M
polymer/o-xylene solution. The solution was heated to 100.degree.
C. and sparged with dry nitrogen until the moisture content of
water was about 5 ppm. Sparging also removed the dissolved oxygen
in the solvent and inerted the reactor. The reactor was then
sealed. The mixture was heated to 220.degree. C. After the
temperature was stabilized, 3.5 mole % of catalyst, titanium
butanediol (based on total moles of polyester monomer repeat
units), were added to the system by pressure transferring the
catalyst into the system with the aid of dry o-xylene (flushing the
catalyst into the system to ensure complete transfer) and nitrogen.
This marked time zero in the experiment. The resulting reaction
mixture was sampled by removing 1-2 ml samples of the mixture
periodically from the system using the system's pressure as the
driving force and a small sintered filter placed in the system to
provide the pressure drop to atmospheric conditions. The collected
samples were analyzed by HPLC to determine yields of macrocyclic
copolyester oligomers. After approximately one hour, the catalyst
was quenched by the addition of water (0.20 mol) by adding the
water in an o-xylene mixture. The water/o-xylene mixture was
pressure transferred into the system, and the system was then
allowed to cool to 75.degree. C. with stirring in progress. The
resulting reacted mixture was then filtered through a heated
filter. Filtration resulted in removal of precipitated linear
impurities (carboxylic acid terminated linear oligomers) from the
system. The filtrate that contained the desired macrocyclic
copolyester oligomers (dissolved in o-xylene at 75.degree. C.) was
then evaporated or roto-evaporated down to about 40 ml and then
nonsolvent (pentane) was added to induce precipitation of the
oligomers. The precipitated macrocyclic copolyester oligomers were
filtered off and dried. Purity of the macrocyclic copolyester
oligomers obtained was greater than 99%, indicated by no observable
hydroxybutyl terminated linears in the product.
Example 1
[0193] Twenty milligrams of
1,1,6,6-tetra-n-butyl-1,6-distanna-2,5,7,10-te- traoxacyclodecane
("stannoxane-1") was dissolved with heating in approximately 2.5 ml
of toluene which had been pre-dried by treating with 4 A molecular
sieves. The solution was cooled and poured into a glass jar
containing 5.0 g of finely pulverized macrocyclic copolyester
oligomer of PBT/PE (95/5 molar ratio). After intimately mixing the
resulting uniform paste was dried under vacuum at about 50.degree.
C. The white crusty solid was pulverized by using a pestle and a
mortar. The resulting uniform free flowing white powder contained
0.3 mole % of tin atoms per mole of the copolyester monomer repeat
units.
Example 2
[0194] Example 1 was repeated except that 33.0 mg of stannoxane-1
catalyst was employed to give a blend containing 0.5 mole % of tin
atoms per mole of the copolyester monomer repeat units.
Example 3
[0195] Di-n-butyltin oxide (24.89 g, 0.100 mole),
2,2-diethyl-1,3-propaned- iol (13.22 g, 0.100 mole) and 75 ml of
toluene were placed in a 250 ml, three necked flask equipped with a
Dean-Stark condenser. The mixture was stirred under nitrogen and
heated to reflux for approximately 2 hours during which time
approximately 1.7 ml of water was separated. The Dean-Stark
condenser was replaced with another Dean Stark condenser filled
with molecular sieves. The reaction mixture was further heated to
reflux for an additional hour and then approximately 60 ml of the
toluene was distilled off. Upon cooling, a white crystalline solid
was obtained. The yield of
1,1-di-n-butyl-4,4-diethyl-1-stanna-2,5-dioxacyclohexane
("stannoxane-2") was 36.1 g.
Example 4
[0196] Approximately one gram of the blend obtained in Example 1
was placed in a 25 ml round bottom flask and it was blanketed with
nitrogen. The flask was then dipped in an oil bath maintained at
190.degree. C. The powder completely melted in one minute to form
an easy-to-flow colorless liquid. The viscosity of the liquid
gradually increased within a period of 2 to 3 minutes and then
started to solidify with crystallization, resulting in formation of
a tough porcelain white solid. The polymerization was complete in
10 minutes.
Examples 5
[0197] Stannoxane-2 (26 mg, 0.0727 mmol) was dissolved in 2 g of
dry toluene. The solution was added to 4.0 g of the macrocyclic
copolyester oligomers obtained in Example A in ajar. The content
was mixed to form a homogeneous white paste. The paste was dried
under vacuum in an oven at approximately 50.degree. C. The crusty
solid blend obtained was ground to obtain uniform powder containing
0.4 mole % tin atoms per mole of the copolyester monomer repeat
units.
Example 6
[0198] Example 5 was repeated except that 13 mg of stannoxane-2
catalyst was used to give a blend containing 0.2 mole % tin atoms
per mole of the copolyester monomer repeat units.
Example 7
[0199] Example 5 was repeated except that 6.5 mg of stannoxane-2
catalyst was used to give a blend containing 0.1 mole % tin atoms
per mole of the copolyester monomer repeat units.
Examples 8-10
[0200] Blend materials obtained in Examples 5-7 were subjected to
test polymerization. One hundred milligrams of each sample were
placed in a one-gram screwcap vial. The vial was capped under
nitrogen. The vial was then dipped in a 190.degree. C. oil bath.
The blend melted in 50-60 seconds to form a colorless fluid. Table
2 shows the times taken to show marked viscosity increase and to
observe a porcelain-white solid following crystallization.
2TABLE 2 Polymerization of the blends Time to show Stannoxane-2
Viscosity increase Start of Conc. (mol %) (min) crystallization
(min) Example 8 0.4 1.5 4.5 Example 9 0.2 2 6 Example 10 0.1 10
18
Example 11
Pultrusion 1, Glass Ribbon
[0201] Pultrusion was done using one end of FGI (Fiber Glass
Industries), 113 yd/lb yield, standard sizing "Flexstrand"
fiberglass roving, and was pulled at a rate of 12 inch/min, first
through a preheating die at 200.degree. C. (4 inch long, 1/2
inch.times.0.025 inch cross section). The blend powder obtained in
Example 1 was then placed on the fibers as they entered a tapered
die (4 inch long, 1/2 inch.times.0.070 inch at the entrance, and
1/2 inch.times.0.015 inch at the exit) that was heated to
200.degree. C. The powder melted and polymerized in the die
(polymerization indicated by (1) molecular weight of 50 k obtained
from GPC analysis, and (2) the apparently high flexural strength as
compared to that of the uncatalyzed macrocyclic oligomers which is
extremely low), and exited in a molten but highly viscous state,
followed by rapid crystallization within 2 inches of the die,
indicated by a visual change from clear to opaque (light tan in
color).
Example 12
Pultrusion 2, Carbon Ribbon
[0202] This example is the same as Example 11 except that the
fiberglass is replaced with Zoltek, 413 ft/lb yield, X-10 sizing,
48 k filament count, carbon fiber. The resulting ribbon also
displayed good mechanical strength, and the resulting polymer had
molecular weight of 50 k based on GPC analysis.
Example 13
Pultrusion 3, Glass Rod
[0203] This example was run at 15 inch/min pull rate, used 3
strands of FGI, 113 yd/lb yield, standard sizing "Flexstrand"
fiberglass roving, with a preheated die at 200.degree. C. The blend
material (in powder form) obtained in Example 1 was placed on the
fibers as they entered a tapered, round die heated to 200.degree.
C. (0.25 inch diameter at the entrance, reducing to 0.125 inch at 1
inch from the entrance, and a constant 0.125 inch diameter for the
remaining 7 inch of the 8 inch long die). The resulting rod was
substantially structural. The resulting polymer had a molecular
weight of 50 k based on GPC analysis.
Example 14
Unidirectional Prepreg
[0204] One gram of macrocyclic PBT oligomer blend material with
stannoxane-1 catalyst is dissolved in 2 grams of methylene chloride
(about 66% by weight of solvent), and combined with about 1 gram of
carbon fiber on a plastic sheet. After the solvent flashed off, the
sample was dry and looked powdery. The powder did not flake off
during handling. The prepreg was then processed in a press,
compression molding, at about 20 psi for 3 minutes at about
200.degree. C. using Teflon sheets. The resulting sheet was
significantly structural.
Example 15
Compression Molding
[0205] Four layers of dry, 5.7 oz./square yard carbon fabric were
used with cyclic PBT blend material spread over the surface, at a
fiber to resin weight ratio of 2:1. The layers with coating ("the
sample") was placed in a heated platen press, at a temperature of
about 190.degree. C., and held at low pressure (less than 5 psi)
for 3 minutes. The sample was then pressed at 200 psi for an
additional 17 minutes. The sample was removed hot, i.e., without
cooling the press. The sample was crystallized and firm.
Example 16
Water slurry
[0206] A blend material of macrocyclic PBT oligomer was prepared by
the process of Example 1, using the catalyst of stannoxane-1. The
blend material was ground to fine powder. The blend material was
then mixed with water and/or ethyl alcohol to create a slurry. The
mixture was allowed to remain in suspension for at least 24 hours.
The material was then heated to remove water and further heated to
cause polymerization of the macrocyclic PBT oligomer. The
polymerization results are listed in Table 3.
3TABLE 3 Water Slurry Process Results (PBT/[Stannoxane-1])
Components of Test mixture in Mixture Id. equal weight Description
Mw % Conversion.sup.a a macrocyclic PBT, miscible 126,030
Medium.sup.b Ethyl alcohol b macrocyclic PBT, miscible 147,300
High.sup.b Ethyl alcohol, water c macrocyclic PBT n/a 155,722
High.sup.b (control) d macrocyclic PBT, suspension 146,698
High.sup.b water .sup.a% Conversion is from macrocyclic
poly(1,4-butylene terephthalate) oligomer to linear polymer.
.sup.bHigh = 95-100%; Medium = 90-95%; Low = less than 90%.
[0207] The procedure was then repeated except that the catalyst in
the blend material was different. The catalyst used here was
commercially available butyltin dihydroxide chloride
(FASCAT.TM.4101 from Atochem). The polymerization results are
listed in Table 4.
4TABLE 4 Water Slurry Process Results (PBT/[FASCAT .TM. 4101])
Components of Test mixture in Mixture Id. equal weight Description
Mw % Conversion.sup.a e macrocyclic PBT, miscible 79,439
Medium.sup.b Ethyl alcohol f macrocyclic PBT, miscible 91,669
Medium.sup.b Ethyl alcohol, water g macrocyclic PBT n/a 126,539
High.sup.b (control) h macrocyclic PBT, suspension 108,213
Medium.sup.b water .sup.a% Conversion is from macrocyclic
poly(1,4-butylene terephthalate) oligomer to linear polymer.
.sup.bHigh = 95-100%; Medium = 90-95%; Low = less than 90%.
Example 17
Water Slurry Prepreg
[0208] A blend material of macrocyclic PBT oligomer was prepared by
the process of Example 1, using the catalyst of stannoxane-1. The
blend material was ground to fine powder. The blend material was
then mixed with water and/or ethyl alcohol to create a slurry. The
mixture was allowed to remain in suspension for at least 24 hours.
Unsized AS4 type carbon fiber was then dipped into the slurry and
removed with a slurry coating. The coated fiber was then dried
under vacuum for 30 minutes at 80.degree. C. to form the prepreg.
The prepreg was cut into 1/2 inch pieces, stacked randomly between
steel sheets, wrapped in aluminum foil, dried again under vacuum
for 30 minutes at 80.degree. C., and pressed at 190.degree. C. for
30 minutes, to make a composite plate. The polymerization result
for the resin in the plate is given in Table 5.
5TABLE 5 Water Slurry Prepreg Process Results (PBT/[Stannoxane-1])
Test Id. Mw % Conversion.sup.a JEG1 136,000 High.sup.b .sup.a%
Conversion is from macrocyclic poly(1,4-butylene terephthalate)
oligomer to linear polymer. .sup.bHigh = 95-100%; Medium = 90-95%;
Low = less than 90%.
[0209] The procedure was then repeated except that the catalyst in
the blend material was different. The catalyst used here was
FASCAT.TM.4101. The polymerization result for the resin in the
plate is given in Table 6.
6TABLE 6 Water Slurry Prepreg Process Results (PBT/[FASCAT
.TM.4101]) Test Id. Mw % Conversion.sup.a JEG2 115,000 High.sup.b
.sup.a% Conversion is from macrocyclic poly(1,4-butylene
terephthalate) oligomer to linear polymer. .sup.bHigh = 95-100%;
Medium = 90-95%; Low = less than 90%.
Example 18
Water Slurry
[0210] The cyclic oligomer employed was a macrocyclic co-polyester
oligomer (c-PBT) with 95 mol % poly(butylene terephthalate) repeat
units and 5 mol % of poly(ethylene terephthalate) repeat units. Two
types of the blend material were formulated. The first blend of
macrocyclic c-PBT oligomer contained homogeneously distributed
stannoxane-1. The concentration of the catalyst was 0.3 mol % of
tin atom based on total moles of monomer repeat units. The second
blend contained 0.4 mol % of FASCAT.TM.4101.
[0211] (1) General Procedure for Making Aqueous Suspension
[0212] Nine grams of macrocyclic c-PBT oligomer blend containing a
polymerization catalyst, 21 ml of water, and a surfactant as
indicated were placed in a 100 ml screw-cap glass bottle along with
five {fraction (7/16)}" stainless steel balls. The tightly capped
bottle was then tumbled for 2 hours. A stable white milky
suspension was obtained.
[0213] (2) Polymerization
[0214] Approximately 5.4 g of the aqueous suspension were spread on
the bottom of a 100 ml beaker and it was dried at 60.degree. C.
under vacuum in an oven. The dried solid powder (0.20 g) was then
placed in a 5 ml test tube. A vacuum was applied and the test tube
was immersed in a 190.degree. C. oil bath. The macrocyclic c-PBT
oligomer melted to form a fluid liquid during a period of 2 min
after which heating was continued under argon atmosphere. Total
polymerization time was 20 min for samples containing 0.3 mol % of
stannoxane-1 and 30 min for samples containing 0.4 mol % of
FASCAT.TM.4101.
[0215] Results from samples containing an anionic surfactant,
various cationic surfactants, and a non-ionic surfactant are
summarized in Tables 7, 8, and 9, respectively.
7TABLE 7 Suspensions Prepared with Anionic Surfactant Polym.
Catalyst Surfactant.sup.a Suspension Polym. Mp.sup.b Sample (mol %)
(ppm) Drying Cond. time Conv (%) (10.sup.3) Control Stannoxane-1
(0.3) Original powder, not suspension 20 min 97.8 140.6 i
Stannoxane-1 (0.3) NaDBS (50) 60.degree. C./vacuum 20 min 93.6
131.2 j Stannoxane-1 (0.3) NaDBS (200) 60.degree. C./vacuum 20 min
95.6 133.2 k Stannoxane-1 (0.3) NaDBS (200) 110.about.120.degree.
C./in air 20 min 91.0 130.4 l Stannoxane-1 (0.3) NaDBS (1000)
60.degree. C./vacuum 20 min 92.9 125.3 m FASCAT .TM. 4101 (0.4)
Original powder, not suspension 30 min 94.8 123.9 n FASCAT .TM.
4101 (0.4) NaDBS (200) 60.degree. C./vacuum 30 min 94.8 114.0
.sup.aNaDBS: Sodium dodecylbenzenesulfonate .sup.bPeak molecular
weight determined by GPC.
[0216]
8TABLE 8 Suspensions Prepared with Cationic Surfactants Polym.
Catalyst Surfactant.sup.a Suspension Polym. Mp.sup.b Sample (mol %)
(ppm) Drying Cond. time Conv (%) (10.sup.3) o Stannoxane-1 (0.3)
DPyr (200) 60.degree. C./vacuum 20 min 93.1 131.9 p Stannoxane-1
(0.3) Im (200) 60.degree. C./vacuum 20 min 94.4 134.8 q
Stannoxane-1 (0.3) DTPP (200) 60.degree. C./vacuum 20 min 95.2
136.8 r Stannoxane-1 (0.3) DTMAB (200) 60.degree. C./vacuum 20 min
95.9 141.3 s FASCAT .TM. 4101 (0.4) DPyr (200) 60.degree. C./vacuum
30 min 94.0 116.2 .sup.aDPyr: Dodecylpyridinium chloride; Im:
1-Octadecyl-3-methylimidazo- lium bromide; DTPP:
Dodecyltriphenylphosphonium bromide; DTMAB:
Dodecyltrimethylammonium bromide. .sup.bPeak molecular weight
determined by GPC.
[0217]
9TABLE 9 Suspension Prepared with Non-ionic Surfactant Polym.
Catalyst Surfactant.sup.a Suspension Polym. Mp.sup.b Sample (mol %)
(ppm) drying time Conv (%) (10.sup.3) t FASCAT .TM. 4101 (0.4) Brij
30 .TM. (200) 60.degree. C./vacuum 30 min 94.0 122.6 .sup.aBrij 30:
Tetra(ethylene glycol) monododecyl ether. .sup.bPeak molecular
weight determined by GPC.
[0218] The chemical stability of the aqueous suspensions may vary
depending on the environment and chemical nature of the components.
Tables 10-11 show the effect of catalyst, surfactant, and
polymerization time on the molecular weight of polyesters
obtained.
10TABLE 10 Chemical Stability of Suspension-1 Polym. Catalyst
Surfactant.sup.a Suspension Polym. Mp.sup.b Sample (mol %) (ppm)
Time (at RT) time Conv (%) (10.sup.3) Control FASCAT .TM. 4101
(0.4) Original dry powder 30 min 94.8 123.9 Control FASCAT .TM.
4101 (0.4) Only H.sub.2O 2 h 30 min 93.1 123.9 u FASCAT .TM. 4101
(0.4) DPyr (200) 2 h 30 min 94.0 116.2 v FASCAT .TM. 4101 (0.4)
DPyr (200) 11 days 30 min 89.4 100.1 w FASCAT .TM. 4101 (0.4) NaDBS
(200) 2 h 30 min 94.8 114.0 .sup.aDPyr: Dodecylpyridinium chloride
(cationic); NaDBS: Sodium dodecylbenzenesulfonate (anionic).
.sup.bPeak molecular weight determined by GPC.
[0219]
11TABLE 11 Chemical Stability of Suspension-2 Polym. Catalyst
Surfactant.sup.a Suspension Polym. Mp.sup.b Sample (mol %) (ppm)
Time (at RT) time Conv (%) (10.sup.3) Control Stannoxane-1 (0.3)
Original dry powder 20 min 97.8 140.6 Control Stannoxane-1 (0.3)
Only H.sub.2O 2 h 20 min .about.95 134.8 x Stannoxane-1 (0.3) DTMAB
(200) 2 h 20 min 95.9 141.3 xx Stannoxane-1 (0.3) DTMAB (200) 12
days 20 min 97.5 137.8 y Stannoxane-1 (0.3) NaDBS (200) 2 h 20 min
93.4 138.7 yy Stannoxane-1 (0.3) NaDBS (200) 11 days 20 min 93.2
124.4 .sup.aDTMAB: Dodecyltrimethylammonium bromide (cationic);
NaDBS: Sodium dodecylbenzenesulfonate (anionic). .sup.bPeak
molecular weight determined by GPC.
[0220] Each of the patent documents disclosed hereinabove is
incorporated by reference herein. Variations, modifications, and
other implementations of what is described herein will occur to
those of ordinary skill in the art without departing from the
spirit and the scope of the invention as claimed. Accordingly, the
invention is to be defined not by the preceding illustrative
description but instead by the spirit and scope of the following
claims.
* * * * *