U.S. patent application number 10/195267 was filed with the patent office on 2003-03-27 for amorphous copolyesters.
Invention is credited to Milburn, Jonathan Terrill, Seo, Kab Sik, Seymour, Robert William, Turner, Sam Richard.
Application Number | 20030060596 10/195267 |
Document ID | / |
Family ID | 26890850 |
Filed Date | 2003-03-27 |
United States Patent
Application |
20030060596 |
Kind Code |
A1 |
Turner, Sam Richard ; et
al. |
March 27, 2003 |
Amorphous copolyesters
Abstract
Disclosed are amorphous copolyesters having an inherent
viscosity (IV) of at least about 0.4 dL/g measured at a temperature
of 25.degree. C. at 0.25 g/dl concentration in a solvent mixture of
symmetric tetrachloroethane and phenol having a weight ratio of
symmetric tetrachloroethane to phenol of 2:3 comprising (1) a
diacid component consisting essentially of about 90 to 100 mole
percent terephthalic acid residues and 0 to about 10 mole percent
isophthalic acid residues; and (2) a diol component consisting
essentially of about 10 to 70 mole percent
1,4-cyclohexanedimethanol residues and about 90 to 30 mole percent
neopentyl glycol residues; wherein the amorphous copolyesters
comprises 100 mole percent diacid component and 100 mole percent
diol component. The amorphous copolyesters are useful in the
manufacture or fabrication of medical devices which have improved
resistance to degradation upon exposure to lipids, as a profile
produced by profile extrusion and as an injection molded article.
Also, a method of melt processing the amorphous copolyester is
disclosed which allows for performing a minimal drying or no drying
of the copolyester prior to melt processing.
Inventors: |
Turner, Sam Richard;
(Kingsport, TN) ; Milburn, Jonathan Terrill;
(Kingsport, TN) ; Seymour, Robert William;
(Kingsport, TN) ; Seo, Kab Sik; (Kingsport,
TN) |
Correspondence
Address: |
J. Frederick Thomsen
Eastman Chemical Company
P.O. Box 511
Kingsport
TN
37662-5075
US
|
Family ID: |
26890850 |
Appl. No.: |
10/195267 |
Filed: |
July 15, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60306221 |
Jul 18, 2001 |
|
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|
Current U.S.
Class: |
528/272 |
Current CPC
Class: |
C08G 63/199 20130101;
C08G 63/183 20130101; Y10T 428/1352 20150115 |
Class at
Publication: |
528/272 |
International
Class: |
C08G 063/02 |
Claims
We claim:
1. An amorphous copolyester having an inherent viscosity (IV) of at
least about 0.4 dL/g measured at a temperature of 25.degree. C. at
0.25 g/dl concentration in a solvent mixture of symmetric
tetrachloroethane and phenol having a weight ratio of symmetric
tetrachloroethane to phenol of 2:3 comprising: (1) a diacid
component consisting essentially of about 90 to 100 mole percent
terephthalic acid residues and 0 to about 10 mole percent
isophthalic acid residues; and (2) a diol component consisting
essentially of about 10 to 70 mole percent
1,4-cyclohexanedimethanol residues and about 90 to 30 mole percent
neopentyl glycol residues; wherein the amorphous copolyesters
comprises 100 mole percent diacid component and 100 mole percent
diol component.
2. The amorphous copolyester of claim 1 wherein the diacid
component consists essentially of at least 95 mole percent
terephthalic acid residues.
3. The amorphous copolyester of claim 1 wherein the diacid
component consists essentially of 100 mole percent terephthalic
acid residues.
4. The amorphous copolyester of claim 1 wherein the diol component
consists essentially of about 30 to 70 mole percent
1,4-cyclohexanedimethanol residues and about 70 to 30 mole percent
neopentyl glycol residues.
5. The amorphous copolyester of claim 1 wherein the diol component
consists essentially of about 35 to 60 mole percent
1,4-cyclohexanedimethanol residues and about 40 to 65 mole percent
neopentyl glycol residues.
6. An amorphous copolyester having an inherent viscosity (IV) of
about 0.6 to 1.1 dL/g measured at a temperature of 25.degree. C. at
0.25 g/dl concentration in a solvent mixture of symmetric
tetrachloroethane and phenol having a weight ratio of symmetric
tetrachloroethane to phenol of 2:3 comprising: (1) a diacid
component consisting essentially of terephthalic acid residues; and
(2) a diol component consisting essentially of about 35 to 60 mole
percent 1,4-cyclohexanedimethanol residues and about 40 to 65 mole
percent neopentyl glycol residues; wherein the amorphous
copolyesters comprises 100 mole percent diacid component and 100
mole percent diol component.
7. A shaped article having improved resistance to degradation from
exposure to lipids wherein the shaped article is fabricated from an
amorphous copolyester having an inherent viscosity (IV) of at least
about 0.4 dL/g measured at a temperature of 25.degree. C. at 0.25
g/dl concentration in a solvent mixture of symmetric
tetrachloroethane and phenol having a weight ratio of symmetric
tetrachloroethane to phenol of 2:3 and comprising: (1) a diacid
component consisting essentially of about 90 to 100 mole percent
terephthalic acid residues and 0 to about 10 mole percent
isophthalic acid residues; and (2) a diol component consisting
essentially of about 10 to 70 mole percent
1,4-cyclohexanedimethanol residues and about 90 to 30 mole percent
neopentyl glycol residues; wherein the amorphous copolyesters
comprises 100 mole percent diacid component and 100 mole percent
diol component.
8. The shaped article of claim 7 wherein the diacid component
consists essentially of at least 95 mole percent terephthalic acid
residues.
9. The shaped article of claim 7 wherein the diacid component
consists essentially of 100 mole percent terephthalic acid
residues.
10. The shaped article of claim 7 wherein the diol component of the
amorphous copolyester consists essentially of about 30 to 70 mole
percent 1,4-cyclohexane-dimethanol residues and about 70 to 30 mole
percent neopentyl glycol residues.
11. The shaped article of claim 7 wherein the diol component of the
amorphous copolyester consists essentially of about 35 to 60 mole
percent 1,4-cyclohexane-dimethanol residues and about 40 to 65 mole
percent neopentyl glycol residues.
12. The shaped article of claim 11 wherein the diacid component
consists essentially of at least 95 mole percent terephthalic acid
residues.
13. The shaped article of claim 11 wherein the diacid component
consists essentially of 100 mole percent terephthalic acid.
14. The shaped article of claim 7 which is transparent medical
device.
15. The medical device of claim 14 which is in the shape of a
tube.
16. The medical device of claim 14 which is in the shape of a
connector.
17. The medical device of claim 14 which is in the shape of a pump
housing.
18. A medical article for contacting solutions containing lipids,
the article fabricated from an amorphous copolyester having an
inherent viscosity (IV) of at least about 0.4 dL/g measured at a
temperature of 25.degree. C. at 0.25 g/dl concentration in a
solvent mixture of symmetric tetrachloroethane and phenol having a
weight ratio of symmetric tetrachloroethane to phenol of 2:3
comprising: (1) a diacid component consisting essentially of about
90 to 100 mole percent terephthalic acid residues and 0 to about 10
mole percent isophthalic acid residues; and (2) a diol component
consisting essentially of about 10 to about 70 mole percent
1,4-cyclohexanedimethanol residues and about 90 to about 30 mole
percent neopentyl glycol residues; wherein the amorphous
copolyesters comprises 100 mole percent diacid component and 100
mole percent diol component.
19. The medical article of claim 18 wherein the diacid component
consists essentially of at least 95 mole percent terephthalic acid
residues.
20. The medical article of claim 18 wherein the diacid component
consists essentially of 100 mole percent terephthalic acid
residues.
21. A medical article for contacting solutions containing lipids,
the article fabricated from an amorphous copolyester having an
inherent viscosity (IV) of about 0.5 to 1.1 dL/g measured at a
temperature of 25.degree. C. at 0.25 g/dl concentration in a
solvent mixture of symmetric tetrachloroethane and phenol having a
weight ratio of symmetric tetrachloroethane to phenol of 2:3
comprising: (1) a diacid component consisting essentially of
terephthalic acid residues; and (2) a diol component consisting
essentially of about 30 to 70 mole percent
1,4-cyclohexanedimethanol residues and about 70 to 30 mole percent
neopentyl glycol residues; wherein the amorphous copolyesters
comprises 100 mole percent diacid component and 100 mole percent
diol component.
22. The medical article of claim 21 wherein the article is a tube,
connector or pump housing.
23. A method of melt processing an amorphous copolyester having a
moisture content prior to melt processing of 0.02 weight % or more
comprising: (a) prior to melt processing, performing a minimal
drying or no drying of the copolyester such that the copolyester
has a moisture content of 0.02 weight % or more prior to melt
processing, and (b) melt processing the copolyester, wherein the
copolyester consists essentially of an acid component of residues
of at least 90 mole percent terephthalic acid and a diol component
consisting essentially of about 30 to about 70 mole percent
1,4-cyclohexanedimethanol residues and about 70 to about 30 mole
percent neopentyl glycol residues, based on 100 mole percent acid
component and 100 mole percent glycol component.
25. The method of claim 24 wherein the diol component consists
essentially of about 30 to less than 70 mole percent
1,4-cyclohexanedimethanol residues and about 70 to 30 mole percent
neopentyl glycol residues.
26. The method of claim 24 wherein the acid component has residues
of at least 95 mole percent terephthalic acid.
27. The method of claim 24 wherein the acid component has residues
of 100 mole percent terephthalic acid.
28. The method of claim 24 wherein prior to melt processing, the
minimal drying is performed, wherein the minimal drying is by
conventional methods for less than 2 hours at 60 to 100.degree.
C.
29. The method of claim 24 wherein prior to melt processing, the
minimal drying is performed, wherein the minimal drying uses a
desiccant bed with forced dehumidified air at 60.degree. C. to
100.degree. C.
30. The method of claim 24 wherein no drying of the copolyester is
performed prior to melt processing.
31. A profile produced by profile extrusion comprising the
amorphous copolyester of claim 1.
32. An injection molded article comprising the amorphous
copolyester of claim 1.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of United States
Provisional Application Serial No. 60/306,221 filed Jul. 18,
2001.
TECHNICAL FIELD OF THE INVENTION
[0002] This invention relates to amorphous copolyesters derived
from 1,4-cyclohexanedimethanol and neopentyl glycol. More
particularly, this invention relates to such copolyesters that have
a combination of unique properties and to shaped articles
fabricated therefrom such as profile extrusions and medical
equipment.
BACKGROUND OF THE INVENTION
[0003] Amorphous copolyesters comprising terephthalic acid (T)
residues and diol residues comprising varying ratios of
1,4-cyclohexanedimethanol (CHDM) residues and ethylene glycol (EG)
residues are well known in the plastics marketplace. As used
herein, the abbreviation PETG refers to copolyesters comprising
terephthalic acid residues as the diacid residue component and a
diol residue component comprising up to 50 mole percent CHDM
residues with the remainder EG residues. PCTG refers to
copolyesters comprising T residues and a diol residue component
comprising greater than 50 mole percent CHDM residues with the
remainder being EG residues. Copolyesters comprising T residues and
diol residues comprising about 20 to 70 mole percent CHDM residues
and about 80 to 30 mole percent EG residues are amorphous. The term
"amorphous" as defined herein means a polyester that does not
exhibit a substantial crystalline melting point when scanned by
differential scanning calorimetry (DSC) at a rate of 20.degree.
C./minute.
[0004] Amorphous copolyesters in general possess a combination of
desirable properties for many applications. These properties
include excellent clarity and color, toughness, ease of processing,
and chemical resistance. Accordingly, amorphous copolyesters are
known to be useful for the manufacture of extruded sheet, packaging
materials, and parts for medical devices, etc. Application in
transparent medical parts requires resistance to craze formation
and mechanical failure when exposed to lipid and/or isopropyl
alcohol (IPA) solutions. Whereas amorphous copolyesters are known
in the art to have good resistance to these chemicals and are
widely applied in these applications, craze formation occurs at
high strains and is thus an area of needed improvement.
Consequently, there is an unmet need for amorphous copolyesters
that under high strains have improved resistance to lipid and IPA
solutions.
[0005] There is also an important need for amorphous copolyesters
that have improved resistance to hydrolytic degradation. U.S. Pat.
No. 5,656,715 discloses that copolyesters containing a diol residue
component comprising 60 to 100 mole percent residues of one of the
isomers of 1,4-cyclohexanedimethanol exhibit improved resistance to
hydrolytic degradation.
[0006] Neopentyl glycol (NPG-2,2-dimethylpropane-1,3-diol) has been
used in combination with EG and terephthalic acid to form amorphous
copolyesters. However, the combination of NPG and CHDM as the diol
component of copolyesters has received minimal attention. Several
early references disclose copolyesters comprising both CHDM and NPG
residues and terephthalic acid residues. Example 46 of U.S. Pat.
No. 2,901,466 describes a copolyester of unknown composition that
was reported to have a crystalline melting point of 289-297.degree.
C. U.S. Pat. No. 3,592,875 discloses copolyester compositions that
contain both NPG and CHDM residues with an added polyol present for
branching. U.S. Pat. No. 3,592,876 discloses polyester compositions
that contain EG, CHDM and NPG residues with the NPG residue level
limited to up to 10 mole percent. U.S. Pat. No. 4,471,108 discloses
low molecular weight polyesters some of which contain CHDM and NPG
residues, but also contain a multifunctional branching agent. U.S.
Pat. No. 4,520,188 describes low molecular weight copolyesters
comprising mixtures of aliphatic and aromatic acid residues with
both NPG and CHDM residues present. Japanese Patent Publication JP
3225982 B2 discloses amorphous copolyesters which are said to be
useful in the formulation of coating compositions for steel sheet.
The disclosed copolyesters comprise a diacid component comprising
mixtures of aliphatic and aromatic acid residues and a diol
component comprising NPG and CHDM residues present.
SUMMARY OF THE INVENTION
[0007] We have discovered that amorphous polyesters derived from
terephthalic acid, CHDM and NPG are valuable compositions useful
for the manufacture of medical devices that exhibit improved
resistance to degradation upon exposure to lipids. The amorphous
copolyesters provided by the present invention have an inherent
viscosity (IV) of at least about 0.4 dL/g measured at a temperature
of 25.degree. C. at 0.25 g/dl concentration in a solvent mixture of
symmetric tetrachloroethane and phenol having a weight ratio of
symmetric tetrachloroethane to phenol of 2:3 and comprise:
[0008] (1) a diacid component consisting essentially of about 90 to
100 mole percent terephthalic acid residues and 0 to about 10 mole
percent isophthalic acid residues; and
[0009] (2) a diol component consisting essentially of about 10 to
70 mole percent 1,4-cyclohexanedimethanol residues and about 90 to
30 mole percent neopentyl glycol residues;
[0010] wherein the amorphous copolyesters comprises 100 mole
percent diacid component and 100 mole percent diol component.
[0011] Another embodiment of the present invention concerns a
shaped article such as an extruded profile or an extruded or
injection molded medical device having improved resistance to
degradation from exposure to lipids wherein the medical device is
fabricated or prepared from an amorphous copolyester having an
inherent viscosity (IV) of at least about 0.4 dL/g measured at a
temperature of 25.degree. C. at 0.25 g/dl concentration in a
solvent mixture of symmetric tetrachloroethane and phenol having a
weight ratio of symmetric tetrachloroethane to phenol of 2:3 and
comprising:
[0012] (1) a diacid component consisting essentially of about 90 to
100 mole percent terephthalic acid residues and 0 to about 10 mole
percent isophthalic acid residues; and
[0013] (2) a diol component consisting essentially of about 10 to
70 mole percent 1,4-cyclohexanedimethanol residues and about 90 to
30 mole percent neopentyl glycol residues;
[0014] wherein the amorphous copolyesters comprises 100 mole
percent diacid component and 100 mole percent diol component.
[0015] In still another embodiment of the present invention, a
method of melt processing an amorphous copolyester having a
moisture content prior to melt processing of 0.02 weight % or more
comprises the steps of:
[0016] (a) prior to melt processing, performing a minimal drying or
no drying of the copolyester such that the copolyester has a
moisture content of 0.02 weight % or more prior to melt processing,
and
[0017] (b) melt processing the copolyester, wherein the copolyester
comprises:
[0018] (1) a diacid component consisting essentially of about 90 to
100 mole percent terephthalic acid residues and 0 to about 10 mole
percent isophthalic acid residues; and
[0019] (2) a diol component consisting essentially of about 10 to
about 70 mole percent 1,4-cyclohexanedimethanol residues and about
90 to about 30 mole percent neopentyl glycol residues,
[0020] wherein the copolyester is based on 100 mole percent diacid
component and 100 mole percent diol component.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows the melt viscosity shear rate curve at
260.degree. C. for PETG, PROVISTA.TM., and the amorphous
copolyester of the present invention described in Example 8. FIG. 2
shows the melt viscosity shear rate curve at 260.degree. C. for
PETG, PROVISTA.TM., and the amorphous copolyester of the present
invention described in Example 10.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Copolyesters comprising based on terephthalic acid (T)
resdiues and, optionally up to about 10 mole percent isophthalic
acid residues, 1,4-cyclohexane-dimethanol (CHDM) residues, and
neopentyl glycol (NPG) residues are amorphous in the approximate
composition ranges of 10 to 70 CHDM to 90 to 30 NPG and these
unique amorphous copolyesters show surprising improved resistance
to crazing when exposed to lipids or IPA. In addition, the
combination of CHDM and NPG as comonomer diols in the copolyesters
of the present invention, results in copolyester backbones that
exhibit enhanced stability to hydrolysis for the amorphous
composition range. The present copolyesters having sufficient
molecular weight to be molding or extrusion grade plastics and
based solely on CHDM and NPG as diols, are not known. In addition,
it is unexpected that the addition of NPG to a copolyester would
improve resistance to lipids and IPA.
[0023] The amorphous copolyesters of the present invention may be
prepared by conventional polymerization processes known in the art,
such as the procedures disclosed in U.S. Pat. Nos. 4,093,603 and
5,681,918. Examples of polycondensation processes useful in the
present invention include melt phase processes conducted with the
introduction of an inert gas stream, such as nitrogen, to shift the
equilibrium and advance to high molecular weight or the more
conventional vacuum melt phase polycondensations, at temperatures
in the range of from about 240 to 300.degree. C. or higher which
are practiced commercially. The terephthalic and isophthalic acid
residues of the copolyesters may be derived from either the
dicarboxylic acids or ester-producing equivalents thereof such as
esters, e.g., dimethyl terephthalate and dimethyl isophthalate, or
acid halides, e.g. acid chlorides. Although not required,
conventional additives may be added to the copolyesters of the
invention in typical amounts. Examples of such additives include
pigments, colorants, stabilizers, antioxidants, extrusion aids,
slip agents, carbon black, flame retardants and mixtures
thereof.
[0024] The polymerization reaction may be carried out in the
presence of one or more conventional polymerization catalysts.
Typical catalysts or catalyst systems for polyester condensation
are well-known in the art. Suitable catalysts are disclosed, for
Example, in U.S. Pat. Nos. 4,025,492,4,136,089, 4,176,224,
4,238,593, and 4,208,527, the disclosures of which are herein
incorporated by reference. Further, R. E. Wilfong, Journal of
Polymer Science, 54, 385 (1961) describes typical catalysts, which
are useful in polyester condensation reactions. Preferred catalyst
systems include Ti, Ti/P, Mn/Ti/Co/P, Mn/Ti/P, Zn/Ti/Co/P, Zn/Al.
When cobalt is not used in the polycondensation, copolymerizable
toners may be incorporated into the copolyesters to control the
color of these amorphous copolyesters so that they are suitable for
the intended applications where color may be an important property.
In addition to the catalysts and toners, other additives, such as
antioxidants, dyes, etc. may be used in the
copolyesterifications.
[0025] The copolyesters of the invention have an inherent viscosity
(IV) of at least about 0.4 dL/g, preferably about 0.5 to 1.1 dL/g,
measured at a temperature of 25.degree. C. at 0.25 g/dl
concentration in a solvent mixture of symmetric tetrachloroethane
and phenol having a weight ratio of symmetric tetrachloroethane to
phenol of 2:3. Preferably, the diacid component consists
essentially of at least 95 mole percent and more preferably 100
mole percent terephthalic acid. The diol component preferably
consists of residues of about 30 to 70 mole percent CHDM residues
and about 70 to 30 mole percent NPG residues. The most preferred
copolyesters have an IV of about 0.60 to 1.1 dL/g and comprise:
[0026] (1) a diacid component consisting essentially of
terephthalic acid residues; and
[0027] (2) a diol component consisting essentially of about 35 to
60 mole percent 1,4-cyclohexanedimethanol residues and about 40 to
65 mole percent neopentyl glycol residues;
[0028] wherein the amorphous copolyesters comprises 100 mole
percent diacid component and 100 mole percent diol component.
[0029] The copolyesters of the invention can be molded and extruded
using conventional melt processing techniques to produce the shaped
article of our invention. The copolyesters are particularly useful
in the manufacture of small and intricately shaped articles such as
tubing used for handling and transporting medical fluids, etc. The
lipid resistance of the copolyesters of our invention under
external strain renders the copolyesters particularly useful in the
manufacture of shaped articles including medical devices such as
tubes, pump housings, connectors, etc. where lipid resistance is
important. Such shaped articles manufactured from the copolyesters
of this invention possess improved resistance to degradation by
medical lipid solutions such as Liposyn II 20% intraveneous fat
emulsion. The improved resistance to degradation is manifested by
retention of elongation to break values (retention of toughness)
and significant reduction of visual crazing in molded test bars as
shown in the examples below.
[0030] The shaped articles may be produced according to
conventional thermoplastic processing procedures such as injection
molding, calendaring, extrusion and rotational molding. The
amorphous copolyesters of the present invention derived from CHDM
and NPG exhibit improved hydrolytic stability at various melt
temperatures. In the conversion of the copolyesters into shaped
articles, the moisture content of the copolyester typically is
reduced to less than about 0.02% prior to melt processing.
[0031] Preferably, prior to melt processing, the minimal drying is
performed by conventional methods for less than 2 hours at 60 to
100.degree. C. For the minimal drying, a desiccant bed with forced
dehumidified air at 60.degree. C. to 100.degree. C. is preferred.
Even more preferably, there is no drying of the copolyester prior
to melt processing.
[0032] The melt viscosity versus shear rate relationship in
polymers is a very important property of polymeric materials. One
useful melt viscosity/shear rate relationship is shear thinning.
Shear thinning occurs when the melt flow is non-Newtonian and shows
a reversible decrease in viscosity with increasing shear rate.
Shear thinning characteristics are very important for allowing the
processing of injection molded and extruded parts and sheets, such
as profiles. Profile extrusion is an extrusion process where
special dies are used to produce articles of asymmetrical shapes.
House siding, plastic tubes, channels, baseboard moldings, etc. are
examples of profile extruded parts and are referred to as profiles.
Generally amorphous polymers are used in profile extrusion to avoid
the shrinking that takes place during crystallization processes.
The asymmetric nature of the products from this process requires
special resin properties such as high melt strength at low melt
viscosities and shear thinning melt rheology. The amorphous
copolyesters of the present invention exhibit improved shear
thinning behavior.
[0033] Referring to the accompanying Figure, FIG. 1 shows melt
viscosity shear rate curves at 260.degree. C. for several polymers:
(1) PETG is a copolyester comprises a diacid component consisting
of 100 mole percent terephthalic acid residues and a diol component
consisting of 69 mole percent ethylene glycol residues and 31 mole
percent CHDM residues and is commercially available as EASTAR.RTM.
6763 Copolyester from Eastman Chemical Company; (2) PROVISTA.TM.
copolyester (also available from Eastman Chemical Company), which
is specifically designed to shear thin by adding branching agents,
has a composition similar to PETG; and (3) the copolyester of
Example 8 of the present invention. Surprisingly, Example 8
exhibits a shear thinning behavior that resembles the PROVISTA.TM.
copolyester and not the PETG. Similarly, FIG. 2 shows melt
viscosity shear rate curves at 260.degree. C. for the copolyester
of Example 10 which shear thins like PROVISTA.TM. copolyester and
not PETG copolyester. For the curves constituting FIGS. 1 and 2,
the complex viscosity was determined by a Rheonmetrics Dynamic
Analyzer (RDA II) with 25 mm diameter parallel plates, 1 mm gap and
10% strain at 260.degree. C. The samples were dried at 60.degree.
C. for 24 hours in a vacuum oven before the frequency sweep
test.
[0034] Thus, based on the shear thinning properties described in
FIGS. 1 and 2, another embodiment of the present invention is a
profile produced by profile extrusion comprising an amorphous
copolyester composition having an inherent viscosity of at least
0.5 dl/g and comprising:
[0035] (1) a diacid component consisting essentially of about 90 to
100 mole percent terephthalic acid residues and 0 to about 10 mole
percent isophthalic acid residues; and
[0036] (2) a diol component consisting essentially of about 10 to
about 70 mole percent 1,4-cyclohexanedimethanol residues and about
90 to about 30 mole percent neopentyl glycol residues;
[0037] wherein the amorphous copolyesters comprises 100 mole
percent diacid component and 100 mole percent diol component.
[0038] Further, another embodiment is an injection molded article
comprising an amorphous copolyester consisting essentially of an
acid component of residues of at least 90 mole percent terephthalic
acid and a glycol component of residues of about 10 to about 70
mole percent 1,4-cyclohexanedimethanol and about 90 to about 30
mole percent neopentyl glycol, based on 100 mole percent acid
component and 100 mole percent glycol component.
EXAMPLES
[0039] The following Examples are intended to illustrate, but not
limit, the scope of the present invention. The inherent viscosities
were measured at a temperature of 25.degree. C. at 0.25 g/dl
concentration in a solvent mixture of symmetric tetrachloroethane
and phenol having a weight ratio of symmetric tetrachloroethane to
phenol of 2:3. The 2.sup.nd cycle glass transition temperatures
were determined according to DSC at a heating rate of 20.degree.
C./min to a temperature of 280-300.degree. C., quenching in liquid
nitrogen to 0.degree. C., and then rerunning the sample and
recording the Tg as the 2.sup.nd cycle glass transition
temperature. Final copolyester compositions were determined by
proton NMR analysis on a 600 MHz JEOL instrument.
Example 1
[0040] A copolyester comprising a diacid component consisting of
100 mole percent terephthalic acid residues and a diol component
consisting of 66 mole percent CHDM residues and 34 mole percent NPG
residues (hereinafter referenced as 100T/85CHDM/15NPG) was
prepared. Dimethyl terephthalate (DMT; 77.6 g, 0.4 mole), NPG
(28.91 g, 0.28 moles), CHDM (46.37 g, 0.32 moles), and 1.49 ml of a
solution containing 15 g of titanium tetraisopropoxide in 250 ml of
n-butanol were added to a 500 ml single-neck, round-bottom flask.
The flask was immersed in a Belmont metal bath that was pre-heated
to 200.degree. C. Immediately after the flask was immersed the
temperature set point was increased to 220.degree. C., and held for
1 hour. After the hour at 220.degree. C. the temperature was
increased to 260.degree. C., and held for 30 minutes. After this
time the theoretical amount of methanol was collected. The pressure
in the flask then was reduced from atmospheric to 0.5 Torr. When
the pressure had been reduced to 0.5 Torr the temperature set point
was raised to 280.degree. C. Stirring was reduced as the viscosity
increased until a stir rate of 15 revolutions per minute (rpm) was
obtained. The vacuum was discontinued and nitrogen was bled into
the flask. The polymer was allowed to solidify by cooling to a
temperature below Tg, removed from the flask and ground to pass
through a 3 mm screen. The inherent viscosity of the polymer was
0.895 dL/g. The polymer had a 2.sup.nd cycle Tg of 87.82.degree. C.
Compositional analysis (by NMR) showed the diol component of the
copolyester consisted of 66.1 mole percent CHDM residues and 33.9
mole percent NPG residues.
Example 2
[0041] A copolyester having the composition 100T/61CHDM/39NPG was
prepared. DMT (77.60 g, 0.40 moles), NPG 33.70 grams (0.33 moles)
of NPG, 39.74 grams (0.28 moles) of CHDM, and 1.49 ml of a solution
containing 15 grams of titanium tetraisopropoxide in 250 ml of
n-butanol were added to a 500 ml single neck round bottom flask and
reacted and polymerized according to the procedure described in
Example 1. The inherent viscosity of the polymer was 0.930 dL/g.
The polymer had a 2.sup.nd cycle Tg of 86.70.degree. C. with no
crystalline melting point observed, and compositional analysis
showed that the diol component of the copolyester consisted of 61.4
mole percent CHDM residues and 38.6 mole percent NPG residues.
Example 3
[0042] A copolyester having the composition 100T/56CHDM/44NPG was
prepared. DMT (77.6 g, 0.40 moles), NPG (38.48 g, 0.37 moles), CHDM
(33.12 g, 0.23 moles), and 1.47 ml of a solution containing 15 g of
titanium tetraisopropoxide in 250 ml of n-butanol were added to a
500 ml, single-neck, round-bottom flask and reacted and polymerized
according to the procedure described in Example 1. The inherent
viscosity of the polymer was 0.938 dL/g. The polymer had a 2.sup.nd
cycle Tg of 85.90.degree. C. with no crystalline melting point
observed, and compositional analysis showed that the diol component
of the copolyester consisted of 55.8 mole percent CHDM and 44.2
mole percent NPG residues.
Example 4
[0043] A copolyester having the composition 100T/45CHDM/55NPG was
prepared. DMT (77.60 g, 0.4 moles), NPG (43.26 g, 0.42 moles), CHDM
(26.50 g, 0.18 moles), and 1.44 ml of a solution containing 15 g of
titanium tetraisopropoxide in 250 ml of n-butanol were added to a
500 ml single neck round bottom flask and reacted and polymerized
according to the procedure described in Example 1. The inherent
viscosity of the polymer was 0.897 dL/g. The polymer had a 2.sup.nd
cycle Tg of 83.66.degree. C. with no crystalline melting point
observed, and compositional analysis showed the diol component of
the copolyester consisted of 44.7 mole percent CHDM and 55.3 mole
percent NPG residues.
Example 5
[0044] A copolyester having the composition 100T/32CHDM/68NPG was
prepared. DMT (77.60 g, 0.4 moles), NPG (48.05 g, 0.46 moles), CHDM
(19.87 g, 0.14 moles), and 1.42 ml of a solution containing 15 g of
titanium tetraisopropoxide in 250 ml of n-butanol were added to a
500 ml single neck round bottom flask and reacted and polymerized
according to the procedure described in Example 1. The inherent
viscosity of the polymer was 1.143 dL/g. The polymer had a 2.sup.nd
cycle Tg of 82.43.degree. C. with no crystalline melting point
observed, and compositional analysis showed the diol component of
the copolyester consisted of 32.3 mole percent CHDM and 67.7 mole
percent NPG residues.
Example 6
[0045] A copolyester having the composition 100T/21CHDM/79NPG was
prepared. DMT (77.60 g, 0.4 moles), NPG (52.83 g, 0.51 moles), CHDM
(13.25 g, 0.09 moles), and 1.40 ml of a solution containing 15 g of
titanium tetraisopropoxide in 250 ml of n-butanol were added to a
500 ml single neck round bottom flask and reacted and polymerized
according to the procedure described in Example 1. The inherent
viscosity of the polymer was 0.925 dL/g. The polymer had a 2.sup.nd
cycle Tg of 80.30.degree. C. with no crystalline melting point
observed, and compositional analysis showed the diol component of
the copolyester consisted of 21.4 mole percent CHDM and 78.6 mole
percent NPG residues.
Example 7
[0046] A copolyester having the composition 100T/15CHDM/85NPG was
prepared. DMT (77.60 9, 0.4 moles), NPG (57.62 g, 0.55 moles), CHDM
(6.62 g, 0.05 moles), and 1.37 ml of a solution containing 15 g of
titanium tetraisopropoxide in 250 ml of n-butanol were added to a
500 ml single neck round bottom flask and reacted and polymerized
according to the procedure described in Example 1. The inherent
viscosity of the polymer was 0.863 dL/g. The polymer had a 2.sup.nd
cycle Tg of 77.78.degree. C. with no crystalline melting point
observed, and compositional analysis showed the diol component of
the copolyester consisted of 14.6 mole percent CHDM and 85.4 mole
percent NPG residues.
Example 8
[0047] A copolyester having the composition 100T/67CHDM/33NPG was
manufactured in a batch pilot plant reactor. DMT (10.215 kg, 22.5
pounds), NPG (4.495 kg, 9.9 pounds), CHDM (5.153 kg, 11.35 pounds),
and 53.4 g of a solution of titanium isopropoxide in n-butanol were
charged into a 68.13 liter (18-gallon) batch reactor with
intermeshing spiral agitators and a distillation column. The
agitators were operated forward for 50 minutes and then reversed
for 10 minutes. The internal temperature was increased to
200.degree. C. and held for 2 hours. The temperature then was
increased to 260.degree. C. and held for 30 minutes. At this time,
the weight of distillate was recorded and the temperature was
increased to 280.degree. C. Upon reaching 280.degree. C. the weight
of distillate again was recorded. The agitator was changed to
switch directions every 6 minutes, and vacuum was applied at a rate
of 13 Torr/minute until full vacuum (0.5 Torr) was reached. The
polymerization mixture was mainatained for 25 minutes at 45 rpm,
and then maintained for 15 minutes at 10 rpm. The copolyester thus
obtained then was immediately extruded and chopped into pellets.
The polymer had an inherent viscosity of 0.791 dL/g, and a 2.sup.nd
cycle Tg of 87.48.degree. C. with no crystalline melting point
observed. Compositional analysis (by NMR) showed the diol component
of the copolyester consisted of 67.4 mole percent CHDM residues and
32.6 mole percent NPG residues. The color values, using the CIE lab
color system, were as follows: L* 82.28, a* -0.44, b* 3.80.
Example 9
[0048] A copolyester having the composition 100T/45CHDM/55NPG was
produced in a batch pilot plant reactor. DMT (10.669 kg, 23.5
pounds), NPG (6.220 kg, 13.7 pounds), CHDM (3.223 kg, 7.1 pounds),
and 53.4 g of a solution of titanium isopropoxide in n-butanol were
charged into a 68.13 liter (18-gallon) batch reactor with
intermeshing spiral agitators and a distillation column. After
charging the raw materials, the manufacturing procedure described
in Example 10 was repeated. The resulting polymer had an inherent
viscosity of 0.844 dL/g, and a 2.sup.nd cycle Tg of 84.08.degree.
C. with no crystalline melting point observed. Compositional
analysis (by NMR) showed the diol component of the copolyester
consisted 45.4 mole percent CHDM residues and 54.6 mole percent NPG
residues. The color values were as follows: L* 83.19, a* -0.27, b*
3.97.
Example 10
[0049] Example 9 was repeated except that the polycondensation was
modified to produce a copolyester having a lower IV. After reaching
full vacuum (0.5 Torr), the agitator was held at 25 rpm for only 30
minutes, and then held for 15 minutes at 10 rpm. The copolyester
polymer then was immediately extruded and chopped into pellets. The
copolyester polymer had an inherent viscosity of 0.713 dL/g, and a
2.sup.nd cycle Tg of 83.41.degree. C. with no crystalline melting
point observed. Compositional analysis (by NMR) showed the diol
component of the copolyester consisted of 44.1 mole percent CHDM
and 55.9 mole percent NPG. The color values were as follows:
[0050] L* 82.79, a* -0.40, b* 3.15.
[0051] The resistance of the following amorphous copolyesters to
attack or degradation by lipid solutions was evaluated:
[0052] Copolyester I: PETG 6763, a commercially-available amorphous
polyester wherein the diacid component consists of 100 mole percent
terephthalic acid residues and the diol component consisting of
about 69 mole percent EG residues and 31 mole percent CHDM
residues; IV=0.71.
[0053] Copolyester II: PCTG 5445, a commercially-available
amorphous polyester wherein the diacid component consists of 100
mole percent terephthalic acid residues and the diol component
consisting of about 38 mole percent EG residues and 62 mole percent
CHDM residues; IV=0.72.
[0054] Copolyester III: Amorphous copolyester of Example 8.
[0055] Copolyester IV: Amorphous copolyester of Example 9.
[0056] Standard tensile test bars (ASTM-D638) of each of the
copolyesters I, II, III, and IV were prepared by injection molding.
The bars were placed on three-point-bend strain rigs at fixed
strains of 0, 0.5, 1.5 and 2.7% while simultaneously being exposed
to Liposyn II 20% intravenous fat emulsion (lipid solution) for 72
hours. Exposure to the lipid solution was accomplished by placing a
2.54 mm.times.1.77 mm (1 inch.times.0.5 inch) patch of filter paper
over the center of the bar and saturating the patch with the lipid
solution initially and then rewetting several times a day. The
treated bars were then subjected to tensile testing according to
ASTM D638. The results of these tensile tests are shown in Table I
wherein the values given for Condition Strain, Yield Strain, and
Elongation at Break are percentages. Yield Stress and Break Stress
are given in megapascals. Each test bar was inspected before and
after the evaluation and given a rating of A=no change, B=slightly
crazed, C=moderately crazed, and D=severly crazed. Similar
resistance tests were run with IPA instead of lipid, with these
results shown in Table II wherein the values are the same as those
for Table I. The control represents samples prior to contact with
lipid solution. An inspection of Tables I and II clearly shows that
the amorphous copolyester of the present invention exhibit better
overall performance than the corresponding commercial amorphous
copolyester I and II. The superior performance is manifested, in
general, by the maintenance of a satisfactory appearance and the
maintenance of high elongation to break after exposure to the lipid
while under strain.
1TABLE I Condition Yield Elongation Yield Break Copolyester Strain
Strain to Break Stress Stress Appearance I Control 5.3 167 48.6
29.2 I 0 5.3 65.4 51.1 25.5 A I 0.5 5.3 63.2 50.5 25.1 A I 1.5 5.3
40 51.5 25.2 D I 2.7 5.2 51.3 49.8 25.9 B II Control 4.7 285 43.4
40.7 II 0 -- -- -- -- -- II 0.5 4.9 289.5 46.7 43.8 A II 1.5 4.9
296.0 46.8 43.3 A II 2.7 -- 6.9 -- 29.5 D III Control 5.7 178.9
43.8 46.8 III 0 5.3 154.9 45.1 43.1 A III 0.5 5.3 148.3 45 41.7 A
III 1.5 5.4 137.7 45.6 40.9 C III 2.7 5.5 140.5 44.9 42.1 B IV
Control 5.3 134.1 47.4 42.9 IV 0 5 102.9 48.4 36.4 A IV 0.5 5.1
99.6 48.8 37.9 A IV 1.5 5.2 24.7 49 36.6 C IV 2.7 5.2 18.1 48 36.9
C
[0057]
2TABLE II Condition Yield Elongation Yield Break Copolyester Strain
Strain to Break Stress Stress Appearance I Control 5.3 167 48.6
29.2 I 0 5.3 79 50.5 25.5 A I 0.5 5.3 36.7 50.3 25.2 C I 1.5 5.3
61.7 45.6 25.1 C I 2.7 7 26.6 41.1 25.9 D II Control 4.7 285 43.4
40.7 II 0 -- -- -- -- -- II 0.5 5 287.7 46.3 43.5 D II 1.5 5.1
296.0 38.1 40.2 D II 2.7 7.3 6.9 33.2 39.5 D III Control 5.7 178.9
43.8 46.8 III 0 5.1 161 45.1 44.7 A III 0.5 5.2 159.4 44.8 43.8 B
III 1.5 5.6 125 44.7 38.9 C III 2.7 5.7 150 42.1 42.9 D IV Control
5.3 134.1 47.4 42.9 IV 0 5.1 114.9 48.1 38.1 A IV 0.5 5.1 104.5
48.3 36.9 B IV 1.5 4.3 4.3 42.5 42.5 C IV 2.7 5.2 5.2 36.4 36.4
D
Example 11
[0058] A copolyester having the composition 100T/64CHDM/36NPG was
produced in a batch pilot plant reactor. DMT (10.215 kg, 22.5
pounds), NPG (4.495 kg, 9.9 pounds), CHDM (5.153 kg, 11.35 pounds),
and 53.4 grams of a solution of titanium isopropoxide in n-butanol
were charged into a 68.13 liter (18-gallon) batch reactor with
intermeshing spiral agitators and a distillation column. The
agitator was operated forward for 50 minutes and then reversed for
10 minutes. The internal temperature was increased to 200.degree.
C. and held for 2 hours. The temperature was then increased to
260.degree. C. and maintained for 30 minutes. After this, the
weight of distillate was recorded and the temperature was increased
to 280.degree. C. Upon reaching 280.degree. C. the weight of
distillate was again recorded. The agitator was changed to switch
directions every 6 minutes, and vacuum was applied at 13
Torr/minute until full vacuum (0.5 Torr) was reached and held for
45 minutes at 25 rpm. The copolyester polymer obtained then was
immediately extruded, and chopped into pellets. The polymer had an
inherent viscosity of 0.678 dL/g. Compositional analysis (by NMR)
showed the diol component of the copolyester consisted of 63.9 mole
percent CHDM residues and 36.1 mole percent NPG residues. The color
values were as follows: L* 82.58, a* -0.66, b* 4.76.
Example 12
[0059] A copolyester having the composition 100T/38CHDM/62NPG was
produced in a batch pilot plant reactor. DMT (10.669 kg, 23.5
pounds), NPG (6.220, 13.7 pounds), CHDM (3.223, 7.1 pounds), and
53.4 grams of a solution of titanium isopropoxide in n-butanol were
charged into a 68.13 liter (18-gallon) batch reactor with
intermeshing spiral agitators and a distillation column. The
agitator was operated forward for 50 minutes and then reversed for
10 minutes. The internal temperature was increased to 200.degree.
C. and maintained for 2 hours. The temperature was then increased
to 260.degree. C. and maintained for 30 minutes. After this, the
weight of distillate was recorded and the temperature was increased
to 280.degree. C. Upon reaching 280.degree. C. the weight of
distillate was again recorded. The agitator was changed to switch
directions every 6 minutes, and vacuum was applied at 13
Torr/minute until full vacuum (0.5 Torr) was reached and maintained
for 45 minutes at 25 rpm. The copolyester polymer obtained then was
immediately extruded and chopped into pellets. The polymer had an
inherent viscosity of 0.692. Compositional analysis (by NMR) showed
the diol component of the copolyester contained 38.1 mole percent
CHDM residues and 61.9 mole percent NPG residues. The color values
were as follows: L* 83.04, a* -0.39, b* 4.60.
[0060] The hydrolytic stability of the following amorphous
copolyester polymers was compared:
[0061] Polymers I and II: Same as Copolyesters I and II defined
above.
[0062] Polymer V: Copolyester of Example 11
[0063] Polymer IV: Copolyester of Example 12
[0064] The procedure used in determining loss in molecular weight
as a result of hydrolysis involved placing a sample of the
copolyester into the barrel of a capillary rheometer and then
heating to either 250.degree. C. or 280.degree. C. and holding for
the specified time. The sample was removed, after this treatment,
and the molecular weight was determined by standard size exclusion
chromatography. The molecular weight loss was calculated from the
equation 1-M.sub.w/M.sub.o where M.sub.w is the molecular weight
after treatment and M.sub.o is the original molecular weight. The
higher the number the greater the weight loss. The values listed in
the "hydrolysis" rows are undried samples, while those listed in
the "thermal" rows refer to samples dried at 60.degree. C. for 48
hours at a vacuum of approximately 5 Torr. The results are shown in
Table III.
3 TABLE III Molecular Weight Loss Melt Melt Polymer Polymer Polymer
Polymer Temp Time I II V VI Hydrolysis 250 5 0.24 0.1 0.05 0.05
Hydrolysis 250 7 0.32 0.15 0.05 0.02 Hydrolysis 250 10 0.43 0.22
0.07 0.01 Hydrolysis 250 15 0.57 0.28 0.11 0.05 Thermal 250 5 0.02
0.02 0.08 0 Thermal 250 7 0.03 0.01 0.08 0.08 Thermal 250 10 0.02
0.02 0.12 0.05 Thermal 250 15 0.02 0.03 0.09 0.07 Hydrolysis 280 5
0.47 0.24 0.07 0 Hydrolysis 280 7 0.61 0.36 0.07 0.02 Hydrolysis
280 10 0.68 0.44 0.07 0.03 Hydrolysis 280 15 0.67 0.57 0.15 0.07
Thermal 280 5 0.07 0.08 0.13 0.1 Thermal 280 7 0.07 0.07 0.16 0.13
Thermal 280 10 0.06 0.06 0.2 0.16 Thermal 280 15 0.1 0.08 0.22
0.19
[0065] The invention has been described in detail with particular
reference to preferred embodiments thereof, but it will be
understood that variations and modifications can be effected within
the spirit and scope of the invention.
* * * * *