U.S. patent number RE34,447 [Application Number 07/222,160] was granted by the patent office on 1993-11-16 for crystalline polyamide composition from dicarboxylic acid mixture and diamine.
This patent grant is currently assigned to Amoco Corporation. Invention is credited to Larry W. Autry, Yu-Tsai Chen, Wassily Poppe, Joel A. Richardson, David P. Sinclair.
United States Patent |
RE34,447 |
Poppe , et al. |
November 16, 1993 |
Crystalline polyamide composition from dicarboxylic acid mixture
and diamine
Abstract
Novel crystalline polyamides having high heat deflection
temperatures when filled are prepared from aliphatic diamines and
either mixtures of terephthalic acid and adipic acid or mixtures of
terephthalic acid, isophthalic acid and adipic acid. The mole ratio
of aliphatic diamine to terephthalic acid, isophthalic acid, and
adipic acid is in the range of about 100:65-95:25-0:35-5. The
polyamides can be filled with about 10 to about 60 parts by weight
of a filler. The mechanical properties of these polyamides are
largely unaffected by absorbed water.
Inventors: |
Poppe; Wassily (Lombard,
IL), Autry; Larry W. (Lisle, IL), Chen; Yu-Tsai (Glen
Ellyn, IL), Richardson; Joel A. (Naperville, IL),
Sinclair; David P. (Winfield, IL) |
Assignee: |
Amoco Corporation (Chicago,
IL)
|
Family
ID: |
27499263 |
Appl.
No.: |
07/222,160 |
Filed: |
July 21, 1988 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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601911 |
Apr 19, 1984 |
|
|
|
|
466899 |
Feb 16, 1983 |
|
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Reissue of: |
699813 |
Feb 8, 1985 |
04603166 |
Jul 29, 1986 |
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Current U.S.
Class: |
524/606; 524/607;
525/432; 528/339; 528/340; 528/347; 528/349 |
Current CPC
Class: |
B32B
27/34 (20130101); C08G 69/265 (20130101); C08K
7/04 (20130101); C08K 7/04 (20130101); C08L
77/00 (20130101) |
Current International
Class: |
B32B
27/34 (20060101); C08G 69/00 (20060101); C08G
69/26 (20060101); C08K 7/00 (20060101); C08K
7/04 (20060101); C08L 077/06 () |
Field of
Search: |
;528/339,340,347,349
;524/606,607 ;525/432 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Journal of Polymer Science (JPS), vol. 42; pp. 249-257; 1960. .
A. J. Yu, et al. "Isomorphous Replacement in Copolyamide Systems:
Adipic and Terephthalic Acids" Journal Polymer Science v. 42 (1960)
pp. 249-257. .
D. Erickson "Plastic for the '90s Some Clever chemistry churns out
a new polymer" Scientific American Nov., 1991, pp.
130-131..
|
Primary Examiner: Anderson; Harold D.
Attorney, Agent or Firm: Schlott; Richard J. Hensley;
Stephen L. Sroka; Frank J.
Parent Case Text
BACKGROUND OF THE INVENTION
This is a continuation-in-part application of Ser. No. 601,911,
filed Apr. 19, 1984, which was a continuation-in-part application
of Ser. No. 466,899, filed Feb. 16, 1983, both abandoned.
Claims
We claim: .[.1. A resinous polyamide comprising the following
recurring units: ##STR2## wherein the mole ratio of the
dicarboxylic acid moieties in the A:B:C units is about
65-90:25-0:35-5 with the proviso that the mole ratio of the
dicarboxylic acid moieties in the B:C units is less than 3:1 and
wherein R, R.sub.1, and R.sub.2 are, independently, divalent
aliphatic hydrocarbyl
radicals of 2 to 14 carbon atoms..]. .[.2. The polyamide of claim 1
wherein the mole ratio of the acid moieties in said A:B:C units is
about 65-80:25-5:15-10..]. .[.3. The polyamide of claim 1 wherein
the mole ratio of said acid moieties in said A:B:C units is about
65:25:10 to about 75:15:10..]. .[.4. The polyamide of claim 1
wherein R, R.sub.1, and R.sub.2 are hexamethylene with the formula
(CH.sub.2).sub.6..]. .[.5. A molded object comprising the polyamide
of claim 1..]. .[.6. A fiber comprising the polyamide of claim
1..]. .[.7. A laminate comprising the polyamide of claim 1..].
.[.8. A filled composition comprising 90 to 40 parts by weight of
the polyamide of claim 1 and 10 to 60 parts by weight
of mineral fiber..]. 9. A filled injection moldable polyamide
composition wherein said polyamide comprises the following
recurring units: ##STR3## wherein the mole ratio of the
dicarboxylic acid moieties in the A:B:C units is about
65-90:25-0:35-5 with the proviso that the mole ratio of the
dicarboxylic acid moieties in the B:C units is less than 3:1,
wherein R, R.sub.1 and R.sub.2 are, independently, divalent
aliphatic hydrocarbyl radicals of 2 to 14 carbon atoms, wherein
about 10 to about 60 percent by weight of the filled composition
comprises a filler selected from the group consisting of glass
fibers.[., glass beads, or.]. .Iadd.and .Iaddend.graphite fibers
.[.or mixtures of the same.]. and wherein the filled polyamide
composition has a heat deflection temperature .Iadd.determined by
ASTM Method D648 .Iaddend.in excess of about 245.degree. C.
.Iadd.after being injection molded using a mold temperature
of 250.degree. F.Iaddend.. 10. The composition of claim 9 wherein
the filler comprises about 30 to about 60 percent by weight of the
filled
composition. 11. The filled injection moldable polyamide
composition of claim 9 wherein the mole ratio of the dicarboxylic
acid moieties in the
A:B:C units is about 65-80:25-5:15-10. 12. The composition of claim
11 wherein said filler comprises about 30 to about 60 percent by
weight of
said composition. 13. The composition of claim 9 wherein said mole
ratio of the dicarboxylic acid moieties in the A:B:C units is about
65:25:10 to about 75:15:10 and said filler comprises about 30 to
about 60 percent by
weight of said composition. 14. The composition of claim 9 wherein
said R,
R.sub.1, and R.sub.2 are hexamethylene. 15. The composition of
claim 13 wherein said R, R.sub.1, and R.sub.2 are hexamethylene of
the formula
(CH.sub.2).sub.6. 16. The composition of claim 9 in the form of a
molded article or a laminate. .[.17. A crystalline polyamide
copolymer consisting essentially of the following recurring units:
##STR4## wherein the mole ratio of dicarboxylic acid moieties in
I:II is about 65:35 to 95:5, wherein R and R.sub.2 are aliphatic
hydrocarbyl radicals of
2 to 14 carbon atoms..]. .[.18. A molded article comprising the
polyamide copolymer of claim 17..]. .[.19. A fiber comprising the
polyamide copolymer of claim 17..]. .[.20. A laminate comprising
the polyamide copolymer of claim 17..]. .[.21. The polyamide
copolymer of claim 17 wherein R and R.sub.2 are hexamethylene of
the formula (CH.sub.2).sub.6..]. .[.22. A filled composition
comprising about 90 to 40 parts by weight of the polyamide
copolymer of claim 17 and about 10 to
about 60 parts by weight of a mineral fiber..]. 23. A filled
injection moldable polyamide copolymer composition, said copolymer
comprising the following recurring units: ##STR5## wherein the mole
ratio of the dicarboxylic moieties in I:II is about 65:35 to 95:5,
wherein R and R.sub.2 are aliphatic hydrocarbyl radicals of 2 to 14
carbon atoms, and wherein about 10 to about 60 percent by weight of
the filled composition comprises a filler selected from the group
consisting of glass fibers.[., glass beads, or.]. .Iadd.and
.Iaddend.graphite fibers, .[.or mixtures of the same.]. and wherein
the filled copolymer has a heat deflection temperature
.Iadd.determined by ASTM Method D648 .Iaddend.in excess of about
245.degree. C. .Iadd.after being injection molded using a
mold temperature of 250.degree. F.Iaddend.. 24. The composition of
claim 23 wherein said filler comprises about 30 to about 60 percent
by weight of said composition. .[.25. The composition of claim 21
wherein R and R.sub.2
are hexamethylene of the formula (CH.sub.2).sub.6..]. 26. A blend
comprising the composition of claim .[.1.]. .Iadd.9 .Iaddend.and
nylon 6,6 wherein said nylon 6,6 comprises from about 1 to about 99
weight percent
of the blend. .[.27. A blend comprising the copolymer of claim 17
and nylon 6,6 wherein said nylon 6,6 comprises from about 1 to
about 99 weight
percent of the blend..]. 28. A process for preparing a polyamide
composition having a heat deflection temperature of at least about
245.degree. C., said process comprising compounding about 90 to
about 40 parts by weight of a polyamide with about 10 to about 60
parts by weight of a filler, said polyamide comprising the
following recurring units: ##STR6## wherein the mole ratio of the
dicarboxylic acid moieties in the A:B:C units is about
65-90:25-0:35-5 with the proviso that the mole ratio of the
dicarboxylic acid moieties in the B:C units is less than 3:1, and
wherein R, R.sub.1, and R.sub.2 are, independently, divalent
aliphatic hydrocarbyl radicals of 2 to 14 carbon atoms, and wherein
said filler is selected from the group consisting of glass fibers,
.[.glass beads, or graphite
fibers.]. or mixtures of the same. 29. The process of claim 28
wherein R, R.sub.1, and R.sub.2 are hexamethylene of the formula
(CH.sub.2).sub.6. .[.30. A crystalline injection moldable polyamide
copolymer having a heat deflection temperature of at least about
245.degree. C. when molded and filled with glass fibers, glass
beads or graphite fibers comprising the following recurring units:
##STR7## wherein the mole ratio of A:B:C units is about
65-90:25-5:30-5..].
.Iadd. . A composition comprising a polyamide copolymer and up to
about 60 wt % of at least one filler selected from the group
consisting of glass fiber and graphite fibers, said copolymer
comprising the following recurring units: ##STR8## .Iaddend.
wherein R and R.sub.2 are aliphatic hydrocarbyl radicals of 2 to 14
carbon atoms, and wherein the said copolymer, after being filled
with glass fibers and injection molded using a mold temperature of
250.degree. F. has a heat deflection temperature determined by ASTM
Method D648 above
about 245.degree. C. .Iadd.32. The filled polyamide copolymer
composition of claim 31 wherein the said heat deflection
temperature determined by ASTM Method D648 is in the range about
245.degree. C. to
305.degree. C. .Iaddend. .Iadd.33. The filled polyamide copolymer
composition of claim 31 wherein said copolymer comprises the
following recurring units: ##STR9## .Iaddend. wherein R, R.sub.1
and R.sub.2 are aliphatic hydrocarbyl radicals
of 2 to 14 carbon atoms. .Iadd.34. The filled polyamide copolymer
composition of claim 31 wherein R and R.sub.2 are
--(CH.sub.2).sub.6 --.
.Iaddend. .Iadd.35. The filled polyamide copolymer composition of
claim 31 wherein said copolymer comprises the following recurring
units: ##STR10##
.Iaddend. .Iadd.36. The filled polyamide copolymer composition of
claim 31 comprising up to 60 wt % of at least one filler selected
from the group consisting of glass fiber and graphite fiber, said
fiber being i the form of cloth. .Iaddend. .Iadd.37. A composition
comprising a polyamide copolymer and up to about 60 wt % of at
least one filler selected from the group consisting of glass fiber,
and graphite fibers, said copolymer comprising the following
recurring units: ##STR11## .Iaddend. wherein the mole ratio of the
dicarboxylic acid moieties terephthalic acid: adipic acid in the
copolymer is at least 0.65, and wherein R and R.sub.2 are aliphatic
hydrocarbyl radicals of 2 to 14 carbon atoms, said copolymer filled
with glass fibers having a heat deflection temperature determined
by ASTM Method D648 above about 245.degree. C. after being
injection molded using a mold temperature of 250.degree. F.
.Iadd.38. The filled polyamide copolymer composition of claim 37,
wherein R and R.sub.2 are --(CH.sub.2).sub.6 --. .Iaddend.
.Iadd.39. The filled polyamide copolymer composition of claim 37
wherein said copolymer comprises the following recurring units:
##STR12## .Iaddend. wherein R, R.sub.1 and R.sub.2 are aliphatic
hydrocarbyl radicals
of 2 to 14 carbon atoms. .Iadd.40. The filled polyamide copolymer
composition of claim 37 wherein said copolymer comprises the
following recurring units: ##STR13##
.Iaddend. .Iadd.41. A molded polyamide copolymer article, said
copolymer comprising the following recurring units: ##STR14##
.Iaddend. wherein R, R.sub.1 and R.sub.2 are aliphatic hydrocarbyl
radicals of 2 to 14 carbon atoms, the proportion of the
dicarboxylic acid moiety terephthalic acid is at least 55 mole %
based on total dicarboxylic acid moieties in the copolymer, and
said copolymer filled with glass fibers has a heat deflection
temperature determined by ASTM Method D648 above about 245.degree.
C. after being injection molded using a mold temperature of
250.degree. F. .Iadd.42. A filled composition comprising up to
about 60 wt % of at least one filler selected from the group
consisting of glass fiber and graphite fiber and a polyamide
copolymer comprising the following recurring units: ##STR15##
.Iaddend. said filled composition having a heat deflection
temperature determined by ASTM Method D648 above about 245.degree.
C. when injection
molded using a mold temperature of 250.degree. F. .Iadd.43. The
filled composition of claim 42 wherein the mole ratio of the
dicarboxylic acid moieties terephthalic acid: adipic acid in the
copolymer is at least 0.65. .Iaddend. .Iadd.44. The filled
composition of claim 42 wherein said copolymer comprises the
following recurring units: ##STR16## .Iaddend.
Description
FIELD OF THE INVENTION
The field of this invention relates to crystalline copolyamides or
terpolyamides from aliphatic diamines (ADA), particularly
hexamethylene diamine (HMDA), and either mixtures of terephthalic
acid (TA) and adipic acid (AA), or mixtures of TA, isophthalic acid
(IA), and AA.
Crystalline polyamides from ADA and mixtures of TA and AA or TA,
IA, and AA, which are polymers of injection moldable quality have
not been suggested or disclosed in the prior art. These polymers
have several distinct advantages over known polyamides. Filled
compositions from ADA and TA, AA and ADA, and TA, IA, and AA having
heat deflection temperatures in excess of about 245.degree. C.
(473.degree. F.) are unknown in the prior art. Also, unlike
conventional polyamides such as Nylon 6 and Nylon 6,6, the
mechanical properties of the polyamide compositions of the present
invention are largely unaffected by moisture absorbed from the
atmosphere during the course of normal use.
References of interest include U.S. Pat. No. 3,553,288, which
discloses polyester blends, some components of which can be TA, IA
or AA. U.S. Pat. No. 4,218,509 discloses various fibers.
Transparent terpolyamides from TA, IA, AA and HMDA moieties are
disclosed in Japanese Patent No. J7021116. British Patent
Application No. 604/49 discloses isomorphous TA, AA-HMDA
polyamides; German Offenlegungschrift No. 2,651,534 discloses
fiber-forming random terpolyamides including TA and IA and very
small amounts of AA with HMDA; Japanese Kokai Nos. J71018809,
J52085516 and J7102818 disclose fibers from TA, IA, AA and HMDA
polyamides. Other references include U.S. Pat. No. 3,551,548 which
discloses amorphous polyamides, U.S. Pat. No. 3,526,524 which
relates to copolyamides from adipic acid and U.S. Pat. No.
4,238,603 which relates to amorphous fibers which can be
crystallized after the amorphous fiber is heat treated at
temperatures above the glass transition temperature. It is clear
from a review of these references that crystalline polayamides
manufactured from ADA and mixtures of TA and AA, or mixtures of TA,
IA, and AA, including filled compositions of these polymers, having
heat deflection temperatures of at least about 245.degree. C., a
molecular weight of about 5,000 to about 60,000, and tensile
strengths of about 20,000 psi to about 40,000 psi, which largely
retain these properties even after reaching equilibrium with
atmospheric moisture, have not been contemplated in the prior
art.
The general object of this invention is to provide compositions of
polyamides derived from ADA and mixtures of TA and AA, or from ADA
and mixtures of TA, IA, and AA which can be reinforced with glass
fibers, glass beads, minerals, or a mixture thereof.
Another object is to provide a resinous polyamide, which when
filled with glass fibers has a heat deflection temperature above
245.degree. C. (473.degree. F.).
We have found that the objects of the instant invention can be
accomplished with a resinous polyamide which comprises the
following recurring units: ##STR1##
Wherein .[.the mole ratio of the dicarboxylic acid moieties in the
A:B:C units is about 65-90:25-0:35-5, with the proviso that the
mole ratio of the dicarboxylic acid moieties in the B:C units is
less than 3:1, and wherein.]. R, R.sub.1, and R.sub.2 are,
independently, divalent aliphatic hydrocarbyl radicals of 4 to 12
carbon atoms.
We have found that, when combined with fillers, polyamides obtained
from ADA, particularly HMDA, with mixtures of TA, LA, and AA or
ADA, particularly HMDA, with TA and AA provided surprisingly
improved properties. The mole ratio range of ADA:TA:IA:AA is about
100:65-90:25-0:35-5. The preferred mole ratio of ADA:TA:IA:AA is in
the range of about 100:65:25:10 to about 100:80:5:15. The preferred
mole ratio range of ADA:TA:AA is about 100:65:35 to about 100:95:5.
The crystalline polyamides, when filled and molded with glass
fiber, .[.glass beads, minerals.]. or a mixture thereof have a beat
deflection temperature in the range of about 245.degree. C. to
about 305.degree. C., as determined by ASTM Method D648.
It is completely unexpected to obtain a heat deflection temperature
above about 245.degree. C. when the instant polyamides are glass
filled. The prior art discloses compositions which have much lower
glass filled heat deflection temperatures. U.S. Pat. No. 4,238,603
discloses compositions useful for forming fibers which have molar
ratios of TA:IA:AA of 68-45:30-40:2-15. Our experimental results
show that these compositions have glass filled heat deflection
temperatures of only about 125.degree. C. We have found,
surprisingly, that by maintaining the TA:IA:AA and the TA:AA molar
ratios within critical ranges, desirably high heat deflection
temperatures can be obtained. This is an unusual feature and
completely unexpected from the prior art since comparable
polyamides have much lower heat deflection temperatures.
The importance of having high heat deflection temperatures is that
it enables the injected molded polyamides to be used in
applications such as the hood of an automobile, shroud for a lawn
mower, chain saw guard, and in electrical connector applications.
In addition to the high heat deflection temperature, the tensile
strength of these polyamides is about 20,000 to about 40,000 psi
which is as high or higher than that of die cast aluminum or zinc
while the specific gravity of our polyamides is about one-half of
that of aluminum or zinc. Thus, these polyamides are particularly
useful in transportation equipment applications. These filled
polyamides also have a flexural modulus in excess of about
1,000,000 to about 3,000,000 psi as determined by ASTM Method D790.
This property is advantageous in applications requiring dimensional
stability. The molecular weight of the instant polyamides is about
5,000 to about 40,000.
Aliphatic diamines useful in preparing the polyamides of the
instant invention include alkylene, polymethylene, and
cycloaliphatic diamines of 2 to 14 carbon atoms. Examples of
preferred diamines include: trimethylhexamethylenediamine;
ethylenediamine; tetramethylenediamine; octamethylenediamine;
nonamethylenediamine; dodecamethylenediamine;
1,2-cyclohexanediamine; 1,3-cyclohexanediamine;
1,4-cyclohexanediamine; 1,3-bis(aminomethyl)cyclohexane;
1,4-bis(aminomethyl)cyclohexane; 3,3'-diamino(dicyclohexylmethane);
3,4'-diamino(dicyclohexylmethane);
4,4'-diamino(dicyclohexylmethane); 1,2-propanediamine;
1,3-propanediamine; 3-amino-1-methylaminopropane;
3-amino-1-cyclohexylaminopropane; hexamethylene diamine; and
dodecamethylene diamine. Most preferred diamines are dexamethylene
diamine and dodecamethylene diamine.
The polyamide composition of the instant invention can be filled
with about 10 to about 60 weight percent glass fibers, glass beads,
minerals, or a mixture thereof, or graphite fibers. Our studies
have shown that high heat deflection temperatures and also the cost
of molding products derived from copolyamides can be reduced by
substituting for part of the polymer about 10 to about 60 weight
percent thereof with glass fibers, glass beads, minerals, or
graphite fibers. Advantageously, the molding composition can
contain from about 20 to about 50 weight percent of glass fibers,
glass beads, minerals, or a mixture thereof, or graphite fibers.
These glass filled copolyamides are much more economical than
molding compositions prepared without the use of the glass fibers,
glass beads, minerals, or graphite fillers. The use of polyimides
and amides as engineering plastics has been limited only by their
relatively high cost. Thus, employing our invention, through which
the inherent cost can be brought down, the commercial application
of polyamides requiring very high flexural strength can be greatly
expanded.
Besides being useful as injection molding resins, these novel
materials can be used as the matrix in composite materials and as
fibers. Further, these compositions may be advantageously blended
with other polymers such as Nylon 6,6.
It is also possible to add to the polyamides of this invention
various conventional additives, such as heat stabilizers, UV
stabilizers, toughening agents, flame retardants, plasticizers,
antioxidants, and pigments either before or after the
polymerization as appropriate.
In the preparation of the instant polyamides, the processes can be
divided into salt preparation, condensation, and polycondensation
sections. The salt preparation section is most conveniently batch
operation so that proper stoichiometry can be achieved. The
condensation section can be batch or fully continuous operations.
The product from the condensation section is a polyamide of
intermediate conversion with an inherent viscosity (60/40
phenol/tetrachloroethane)(TCE) at 30.degree. C. of about 0.1 to
about 0.6 dl/g. This polymer is then finished to an inherent
viscosity of about 0.8 dl/g or greater in a twin-screw extruder
reactor. This finished polymer is then compounded with suitable
filler materials. The preferred processes for preparation of these
polyamides are presented herein below.
The addition of reinforcing materials improves the material
properties of the blend, particularly the physical properties such
as flexural strength, are improved if the polyamides contain from
about 10 to about 60 percent by weight glass fibers, glass beads,
minerals, or mixtures thereof. In the preferred range, the
polyamides contain about 20 to about 50 percent by weight of glass
fibers, glass beads, or graphite, or mixtures thereof. Suitably,
the reinforcing materials can be glass fibers, glass beads, glass
spheres, or glass fabrics. The preferred fillers are glass fibers.
These are made of alkali-free, boron-silicate glass or
alkali-containing C-glass. The thickness of the fibers is, on the
average, between 3 microns and 30 microns. It is possible to use
long fibers in the range of from 5 mm to 50 mm and also short
fibers with each filament length of 0.05 mm to 5 mm. In principle,
any standard commercial grade fiber, especially glass fibers, can
be used. Glass beads ranging from 5 microns to 50 microns in
diameter may also be used as a reinforcing material.
The glass fiber reinforced polyamide polymers can be prepared by
any conventional method. Suitably, so-called roving endless glass
fiber strands are coated with the polyamide melt and subsequently
granulated. The cut fibers and glass beads can also be combined
with granulated polyamides compositions and the resulting mixture
melted in a conventional extruder. Alternatively, the fibers can be
introduced into the molten polyamides through a suitable inlet in
the extruder.
The injection molding of the instant polyamides is accomplished by
injecting the polyamide into a mold maintained at a temperature of
about 100.degree. C. to about 200.degree. C. In this process, a
20-second to 1-minute cycle is used with a barrel temperature of
about 300.degree. to about 350.degree. C. These temperatures can
vary depending on the Tg and Tm of the polyamide being molded. The
instant copolyamide compositions have excellent heat deflection and
other physical properties.
The following procedures and examples illustrate a preferred
embodiment of this invention, It is understood that these
procedures and examples are illustrative only and do not purport to
be wholly definitive with respect to the conditions or scope of the
invention. While the desired polymer properties can be obtained
regardless of the method of preparation, provided an adequate
molecular weight is attained, the continuous process outlined in
Procedure B represents a practical process for the commercial
production of polyamides with high terephthalic acid content. The
presence of high levels of terephthalic acid renders these polymers
high melting and highly viscous. Chapman, et al, U.S. Pat. No.
4,022,756, describe the extraordinary means which must be employed
in order to obtain acceptable polymer with terephthalic acid
contents of 60 to 80 mole percent in conventional polycondensation
polymerization equipment.
The components used in the polymerization mixtures described below
were polymerization grade materials including: Amoco Chemicals
Corporation grade TA-33 terephthalic acid and grade IPA-99
isophthalic acid; Monsanto Corporation adipic acid and aqueous
hexamethylenediamine solution which is typically about 70 weight
percent HMDA in water; benzoic acid (USP); and deionized water. The
glass fibers used were 1/2 inch long with a diameter of about 9.7
micrometers and were supplied by Pittsburgh Plate Glass, grades PPG
3531 and PPG 3540, or similar materials.
Procedure A--Batch Preparation of Polyamide
Batch production of these polyamides can be carried out in one or
two steps. It is convenient to carry out the process in two steps.
In the first step, a polyamide of intermediate conversion is
prepared in a stirred reactor which can process materials of high
viscosity. For this process, feed materials consisting of the
diacids (TA, IA, and AA in the desired ratios), the diamine (as
commonly used herein aqueous HMDA), and any additives are charged
to the reactor at about room temperature to 175.degree. F. Water
sufficient to attain a homogeneous solution before pressure letdown
begins is also added. For the equipment described in the examples
which follow, the water content is about 15 percent by weight. The
temperature of this polymerization mixture is then raised to
between about 500.degree. F. and 600.degree. F. as rapidly as
possible. Pressure, principally steam pressure, is allowed to build
to the pressure limits of said reactor (in this case, 130 psig).
Once the target temperature is reached, the pressure is reduced to
atmospheric pressure over a period of 5 to 120 minutes. The polymer
is then allowed to flow out of the reactor by gravity or is pumped
out and collected under an inert atmosphere. This polymer has an
inherent viscosity (TCE/phenol) of about 0.10 dl/g to about 1.0
dl/g or greater. Preferably, the inherent viscosity is about 0.10
dl/g to about 0.40 dl/g. This polyamide of intermediate conversion
is then granulated and fed to the final polycondensation section.
This final polycondensation section is described below.
Alternatively, if the inherent viscosity of this batch-prepared
polymer exceeds about 0.8 dl/g, it can be compounded directly with
the reinforcing filler materials as described in Procedure C.
When these polyamides are prepared by the above described process,
and the resultant inherent viscosity is less than about 0.8 dl/g,
the polyamide must be finished to an inherent viscosity of about
0.8 dl/g or greater in order to fully realize the improved
properties of the instant polyamides. This finishing process is the
final polycondensation step and utilizes a twin-screw extruder
reactor. The twin-screw extruder allows these stiff, high melting
resins to be easily handled. The screw configuration employed when
the twin screw extruder is used as a polycondensation reactor
consists of four basic sections. The first section is a feed
section which is composed of relatively long pitches for conveying
the polymerization mixture away from the feeding port. The second
section is a short compression section which compresses the
polymerization mixture and provides a melt seal for the reaction
zone. The reaction zone comprised about 70-80 percent of the entire
length of the extruder. Typically, the screw flights have
relatively long pitches, but various mixing elements or kneading
blocks can be included in this section. The final section is also a
compression section which feeds the die. Other types of finishing
reactors such as disk ring reactors, agitated stranding
devolatilizers, and thin film evaporators can be utilized; however,
some of these can have difficulty in handling the high viscosity of
our resins.
Procedure B--Continuous Preparation of Polyamide
The dicarboxylic acids, diamine, water, and any additives are
charged to the salt reactor at room temperature. The salt reactor
consisted of a 5-gallon stirred tank reactor with internal coils,
an oil jacket for temperature control, and a pitched-blade turbine
with a variable speed drive. This reactor can accommodate a 60
g-mole charge of the polyammonium carboxylate salt components.
Once the salt reactor has been charged, it is purged with nitrogen
or other inert gas and heated to 420.degree. F. (216.degree. C.).
The pressure is set to 480 psig by first allowing the water in the
salt to reach its equilibrium pressure and then adjusting with
nitrogen. In the fed batch operations, the salt is subjected to a
range of residence times. They average about 100 minutes. Also, as
a result of the fed-batch mode of operation, it is necessary to
include a second surge vessel in the salt preparation section. This
vessel, which is at 420.degree. F. (216.degree. C.) and 450 psig,
is used to isolate the salt reactor during charge addition.
Upon leaving the salt section, the salt is passed through a 140
micron filter into a two-headed positive displacement Bran-Lubbe
pump. Temperature through the pump is maintained at 406.degree. F.
(208.degree. C.). Pressures are increased to 1800 psig in the pump.
After passing through the pump, the salt solution was passed
through a preheat zone and heated to 622.degree. F. (328.degree.
C.). The pressure prevents vapor formation in the preheater.
Residence time in the preheater is 40 seconds.
The salt enters the flash reactor through a valve manufactured by
Research Control Valve (RCV) where pressure is reduced from about
1800 psig to about 0 to 400 psig. In ordinary operation, this flash
reactor is a tubular reactor about 10 to 14 feet long with an
internal diameter of 0.375 to 0.5 inches. The wall temperature of
this reactor is maintained at about 700.degree. to 750.degree. F.
The necessary heat is supplied by hot oil jacket, electrical
heaters, or other means. The internal temperature of this reactor
is monitored along its length. The temperature of the reaction
mixture is between about 525.degree. F. and 630.degree. F. within
this reactor. The pressure within the flash reactor is controlled
by a second RCV. The residence time in the flash reactor is about
10 seconds. Alternatively, this reactor may be a conventional
stirred tank reactor. Example IV presents such a configuration.
Specific process data for the examples using this flash reactor are
presented below in Table I.
TABLE I ______________________________________ Process Conditions
Preheat Reactor Reactor Exam- Temp Press Temperature, .degree.F.
Pressure ple .degree.F. Psig GPH 1/4 1/2 3/4 Final Psig
______________________________________ I 630 1700 1.5 575 580 607
617 50 III 607 1700 1.75 515 544 562 578 60 V 640 1850 1.8 541 556
576 592 50 ______________________________________
Upon exiting the flash reactor, the reaction mixture is injected
directly onto the screws of a twin-screw extruder/reactor, the
Werner-Pfleiderer ZSK-30, described in Procedure A above. As in
Procedure A, the twin-screw extruder increases the molecular weight
of the polymer, to provide an inherent viscosity of the finished
polymer of about 0.8 dl/g or greater. The process conditions
employed in the twin-screw reactor for each of the examples are
presented in Table II below.
TABLE II
__________________________________________________________________________
ZSK-30 Conditions Screw Speed Torque Zone Temperature, .degree.F.
Temperature, .degree.F. Product Example Rpm Percent 1 2 3 4 5 Die
Final Melt Rate lb/hr IV
__________________________________________________________________________
1 120 33 600 585 575 575 570 570 580 9.0 0.95 III 125 15 610 610
590 570 570 565 570 9.7 0.80 V 125 28 620 620 620 565 550 550 556
9.0 0.81
__________________________________________________________________________
Procedure C--Polyamide Compounding
Two techniques are employed to prepare compounded samples for
injection molding. The first of these is dry blending, which is
especially convenient for the preparation of small samples. Dry
blending simply involves combining weighed amounts of the resin,
filler, and any other additives. These ingredients are then mixed
by tumbling, stirring, etc., until the mixture is homogeneous. This
dry blend can be either injection molded directly by Procedure D,
or used as a feed for melt compounding.
Melt compounding involves melting the polymer resin in the presence
of the filler or adding filler to the polymeric melt. This is
conveniently accomplished in a twin-screw extruder, such as the
above mentioned ZSK-30. The basic screw configuration used for melt
compounding is composed of three sections. The first section, the
feed section, has relatively long pitches for conveying the
material away from the feeding port. The second section is a
compression section in which the screw flights have shorter
pitches. In this section, the resin is melted and further mixed
with the filler. The third section is a decompression section in
which the longer pitches are again used to degas the polymer melt.
Advantageously, this section is vented. The polymer melt passes
through a die to strand the compounded resin which is then chopped
into pellets. The specific conditions employed in melt compounding
the compositions of the instant invention and the comparative
examples are presented in Table III below.
TABLE III
__________________________________________________________________________
Compounding Conditions, ZSK-30 Die Product Screw Zone Temperature,
.degree.F. Temp Rate Example Speed Torque 1 2 3 4 5 .degree.F.
lb/hr Comments
__________________________________________________________________________
I 140 75 630 625 625 620 615 615 9.5 III 200 30 585 590 605 615 615
615 13 w/o/nucleant 200 25 585 590 600 605 595 605 17 w/nucleant V
90 41 535 600 600 600 600 600 17 VII 170 50 530 620 625 635 625 600
15 X 130 26 595 570 585 575 570 590 7.7 60% Fran. Fiber 140 30 650
650 645 635 635 620 18 40% PMF 204
__________________________________________________________________________
Procedure D--Forming of Objects from the Glass Filled
Compositions
The compositions of the instant invention are melt processible.
Injection molding is a common technique for forming polymeric
materials into useful shapes and objects. The heat distortion
temperature specimens used to exemplify this invention were
prepared in a 1.5 oz Arburg injection molding machine, Model 221E,
in accordance with ASTM procedures.
Injection molding is an art. The precise conditions employed depend
not only on the molding machine being used and the part being
formed, but also on the melt viscosity of the polymeric resin and
the level and nature of the fillers used. A thorough procedure of
establishing an injection molding cycle is described in Nylon
Plastics by Melvin I. Kohan in Chapter 5, "Injection Molding of
Nylons," pp. 156-205, John Wiley & Sons, Publishers (1973)
incorporated herein by reference. General conditions for injection
molding of ASTM specimens on the Arburg Model 221E, injection
molding machine are presented in Table IV.
TABLE IV ______________________________________ Mold Temperature
100.degree. to 200.degree. C. Injection Pressure 6,000 to 15,000
psi and held for 10 to 20 seconds Back Pressure 100 to 1,000 psi
Cycle Time 20 to 60 seconds Extruder 320.degree. to 340.degree. C.
Nozzle Temperature Barrel Heated to 270.degree. to 370.degree. C.
Screw 20 to 60 Revolutions/minute
______________________________________
The temperature of the mold was controlled. This mold temperature
is cited in each example. The aforementioned procedures were
employed not only for the examples which embody the present
invention, but they were also employed in the preparation of
comparative examples from the prior art. The examples also
demonstrate that the unexpected increase in heat deflection
temperature upon filling is a property of the polymer and not of
the method of preparation.
EXAMPLE I
Preparation of 75/15/10-100 (TA/IA/AA--HMDA) Terpolymer
Chapman, et al, in U.S. Pat. No. 4,022,756, describe in great
detail the difficulties associated with the preparation of
polyamides with greater than 60 mole percent terephthalic acid.
This polymeric resin containing 75 mole percent terephthalic acid
was prepared by Procedure B. The charge to the salt reactor
consisted of:
______________________________________ Component Amount, g
______________________________________ Terephthalic acid (TA)
7401.5 Isophthalic acid (IA) 1480.3 Adipic acid (AA) 868.1 Benzoic
acid (BA) 146.6 Hexamethylenediamine (HMDA) 7112.1 Water 4300
NaH.sub.2 PO.sub.2.H.sub.2 O 13.8
______________________________________
Benzoic acid was employed to control molecular weight. The salt
reactor was heated to 450.degree. F. and maintained at a pressure
of 450 psig to provide a homogeneous solution. The salt solution
was then metered through a pump into the preheat zone which was
maintained at about 630.degree. F. and 1700 psig. The reaction
mixture was then flashed into the tubular reactor through the RCV.
Reactor pressure was maintained at 50 psig. The temperature within
this flash reactor ranged from 558.degree. F. to 623.degree. F. The
product from this flash reactor passed directly into a ZSK-30
twin-screw reactor/extruder. The temperature profile of the ZSK-30
ranged between 600.degree. F. and 570.degree. F., and the screw
speed was 120 rpm. The overall production rate was about 9.0 lb/hr.
The inherent viscosity of the product from the ZSK-30 was 0.95
dl/g. The process data are presented in Tables I and II. The heat
deflection temperature of this resin at 264 psi was 260 .degree. F.
when tested in accordance with ASTM method D648. The HDT specimens
were prepared in accordance with Procedure D using a 250.degree. F.
mold temperature.
When compounded with 30 wt. percent glass by Procedure C and once
again molded in accordance with Procedure D using a 250.degree. F.
mold temperature, the HDT at 264 psi was 502.degree. F.
EXAMPLE II
Batch Preparation of 75/15/10 (TA/IA/AA--HMDA) Terpolyamide
The following ingredients were charged into a 10CV Helicone reactor
(Atlantic Research Corp.) which was preheated to 170.degree. F.
______________________________________ Component Amount, g
______________________________________ TA 3188 IA 638.0 AA 374.0
HMDA 4326 H.sub.2 O 908 NaH.sub.2 PO.sub.2.H.sub.2 O 5
______________________________________
Once charged, the polymerization mixture was heated while being
agitated at about 40 rpm for about 90 minutes. During this time,
the reactor pressure reached 120 psig and was controlled at this
pressure. After 90 minutes, the temperature of polymerization had
reached 500.degree. F. The reactor was then vented while the melt
temperature was maintained at 500.degree. F. Once the reactor
pressure had reached 0 psig, the contents of the reactor were
dumped into water for cooling.
The product was ground and then dried in a forced air oven at
175.degree. F. for 18 hours. The inherent viscosity of this polymer
was 0.20 dl/g.
The polyamide of intermediate conversion was finished in the ZSK-30
twin-screw extruder reactor as outlined in Procedure A. The
inherent viscosity of the finished terpolyamide was 1.16 d./g. The
heat deflection temperature at 264 psi was found to be 256.degree.
F.
When this 75/15/10-100 (TA/IA/AA-HMDA) terpolyamide was dry blended
with 45 wt. percent glass fiber, PPG 3531, and injection molded by
Procedure D, the mold temperature was 250.degree. F. The heat
deflection temperature at 264.degree. psi (ASTM D648) was
580.degree. F.
EXAMPLE III
Continuous Preparation of 65/25/10 (TA/IA/AA-HMDA) terpolymer
Fourteen preparations of identical composition and similar inherent
viscosity (0.8-1.0 dl/g) were prepared according to Procedure B.
Three hundred pounds of these resins were blended together in a
Patterson-Kelly 10 cubic foot twin-shell triblender at 20 rpm for
30 minutes.
A typical preparation of a resin for this blend was as follows. The
5 gallon salt reactor, was charged with:
______________________________________ Component Amount, g
______________________________________ TA 6414.7 IA 2469.2 AA 868.1
BA 146.6 HMDA 7112.1 NaH.sub.2 PO.sub.2.H.sub.2 O 13.8
______________________________________
Once the salt reactor was charged, it was purged with nitrogen and
heated to about 420.degree. F. The pressure set point was 480 psig,
and this was attained by a combination of steam pressure and
nitrogen gas pressure. The salt solution was then continuously
passed through the reactor system. In the preheat zone, the
pressure was increased to 1800 psig and the temperature was
622.degree. F. Residence time in the preheat zone was 40 seconds.
The flash reactor was maintained at 40 psig. The temperatures
within the flash reactor ranged from 525.degree. F. to 612.degree.
F. depending upon location within the flash reactor. Residence time
in the flash reactor was about 7.6 seconds. The effluent from the
flash reactor was injected directly onto the screws of the
extruder. The screw speed was 40 rpm. The temperature in the
injection zone was 615.degree. F., the melt temperatures were
stepped down to 565.degree. F. at the die head over the length of
the extruder. Total production was 20 lbs of 0.8 dl/g polymer. The
process details are summarized in Tables I and II.
When the blend of these resins was molded in accordance with
Procedure D, 250.degree. F. mold temperature, the heat deflection
temperature at 264 psi was 256.degree. F. This resin was compounded
with 30 wt. percent glass fibers, PPG 3540, and molded according to
the foregoing procedures. The mold temperature was varied with the
following results:
______________________________________ Mold Temperature, .degree.F.
HDT, .degree.F. ______________________________________ 200 451 250
481 300 500 ______________________________________
When 1 wt. percent sodium phenylphosphinate, a nucleating agent,
was added during the compounding procedure, higher heat deflection
temperatures were realized at low mold temperatures.
______________________________________ Mold Temperature, .degree.F.
HDT, .degree.F. ______________________________________ 200 471 250
495 300 498 ______________________________________
EXAMPLE IV
Alternative Preparation of 65/25/10-100 (TA/IA/AA-HMDA)
Terpolymer
In this example, a series of three stirred-tank reactors were
employed to obtain a polycondensate with an inherent viscosity of
about 0.1 to 0.2 dl/g. The high melt viscosity and high melt
temperature of these polymers limited the inherent viscosity which
could be obtained in the series of reactors. This low inherent
viscosity material was then finished to an inherent viscosity of
1.26 dl/g in the ZSK-30 extruder/reactor.
In this process, the ingredients were charged to a 5 gallon salt
reactor as in Procedure B. The charge was the same as in Example
III. The salt reactor was operated at 450 psig and 450.degree. F.
The effluent from this reactor was then passed to a second reactor
of similar design which was operated at 425 psig and 450.degree. F.
The effluent from this second reactor was then let down into a
poly-condensation reactor operated at 350 psig and 460.degree. F.
The residence time in this third reactor was 30 minutes. At the end
of this time, the reactor was vented to atmospheric pressure and
the solid product removed. The solid product (inherent viscosity
0.12 dl/g) was fed to the ZSK-30 twin-screw extruder/reactor. The
extruder was operated at atmospheric pressure with an average
barrel temperature of 670.degree. F. The residence time in the
extruder was about 2 minutes. The product inherent viscosity was
1.26 dl/g. When molded in accordance with ASTM D648 using a 250
.degree. F. mold temperature, the HDT at 264 psi was 237.degree.
F., which is 19.degree. F. lower than for the similar composition
of Example III.
When this resin was dry blended with either 30 wt. percent or 45
wt. percent glass fibers, PPG 3540, and molded using a 250.degree.
F. mold temperature, the HDT's at 264 psi were:
______________________________________ Glass Fibers Percent by
Weight HDT, .degree.F. ______________________________________ 30
509 45 533 ______________________________________
These values are higher than in the previous example, but they are
within typical variations for resins of similar compositions but
different molecular weights.
EXAMPLE V
Continuous Preparation of 65/35-100 (TA/IA-HMDA) Copolymer
This material is a comparative example of a terephthalic acid
containing polyamide which does not display a substantial increase
in HDT when filled with 30 wt. percent glass fibers even though the
mole percent terephthalic acid is identical to that of the previous
two examples. The neat resin was prepared according to Procedure
B.
The following charge was placed in the salt reactor:
______________________________________ Component Amount, g
______________________________________ TA 6447.1 IA 3471.5 BA 73.3
HMDA 7112.1 H.sub.2 O 3100 NaH.sub.2 PO.sub.2.H.sub.2 O 13.8
______________________________________
Process conditions are found in Tables I and II. The unfilled
copolyamide had a heat deflection temperature at 264 psi of
253.degree. F. when a 250.degree. F. mold temperature was used.
When this composition was compounded with 30 wt. percent glass
fibers, PPG 3540, and injection molded using a 250.degree. F. mold
temperature, the HDT at 264 psi, increased only 17.degree. F. to
270.degree. F.
EXAMPLE VI
Batch Preparation of a 60/30/10-100 (TA/IA/AA-HMDA)
Terpolyamide
The following charge was added to a 10CV helicone reactor (Atlantic
Research Corp.):
______________________________________ Component Amount, g
______________________________________ TA 4250 IA 2125 AA 623 (70%
aqueous) HMDA 7392 H.sub.2 O 1680 NaH.sub.2 PO.sub.2.H.sub.2 O 11.9
Silicone oil 12.0 ______________________________________
Once charged the polymerization mixture was heated while being
agitated at about 40 rpm for 105 minutes. At the end of this time
the polymerization mixture had reached 585.degree. F., and the
reactor pressure had reached 120 psig and was maintained at that
pressure as the melt temperature increased. Once the melt
temperature reached 585.degree. F., the reactor was vented to 0
psig over a 10 minute period. The polymer was then drained from the
reactor into a water quench. The polymer was ground and then dried
overnight under vacuum at about 200.degree. F. The resin inherent
viscosity was 0.95 dl/g. This resin was not evluated neat, rather
it was dry blended with 30 wt. percent glass fibers, PPG 3531, and
injection molded according to Procedure D. A 250.degree. F. mold
temperature was used. The heat deflection temperature at 264 psi
was 257.degree. F., very similar to that of the previous example,
and approximately 224.degree. F. lower than that of the 30 percent
glass filled 65/25/10 terpolyamide of Example III.
EXAMPLE VII
Batch Preparation of 55/35/10-100 (TA/IA/AA-HMDA) Terpolyamide
The following materials were charged into the 10CV helicone reactor
(Atlantic Research):
______________________________________ Component Amount, g
______________________________________ TA 4112 IA 2617 AA 658 HMDA
5386 H.sub.2 O 3209 NaH.sub.2 PO.sub.2.H.sub.2 O 12.0 Silicone oil
12.0 ______________________________________
The polymerization mixture was heated with agitation to 575.degree.
F. This temperature was reached after 148 minutes. During this
time, the reactor pressure increased to 110 psig. The reactor
pressure was maintained at 110 psig until the 575.degree. F. melt
temperature was attained. The reactor pressure was then released to
0 psig over a period of 15 minutes. A nitrogen purge was introduced
into the reactor and the melt temperature increased to 606.degree.
F. over a seven minute period. The polymer was then discharged into
a water quench. The polymer was ground and dried in a vacuum oven
at 230.degree. F. for 16 hours. The polymer inherent viscosity was
1.08 dl/g. When molded using a 250.degree. F. mold, the HDT at 264
psi was 225.degree. F.
When this terpolyamide was compounded with 30 wt. percent glass,
PPG 3540, according to Procedure C and injection molded using a
250.degree. F. mold temperature, the HDT at 264 psi was 243.degree.
F. A nucleated grade of this material was also compounded. In
addition to 30 wt. percent glass fibers, 1.5 wt. percent sodium
phenyl phosphinate, a nucleating agent, was added during the
compounding. This material was injection molded at mold
temperatures of 200.degree. and 250.degree. F. with the following
results:
______________________________________ Mold Temperature, .degree.F.
HDT, .degree.F. ______________________________________ 200 292 250
267 ______________________________________
The results from Examples I through VI show the advantage of the
instant invention compared to the compositions disclosed in the
prior art. The prior art does not teach the use of 65/35
(TA/IA-HMDA) copolymer (Example V), 60/30/10 (TA/IA-HMDA)
terpolymer (Example VI), or 55/35/10 (TA/IA/AA-HMDA) terpolymer
(Example VII) as glass filled injection molding compositions
because these three materials are not suited for this application.
The comparative results show these resins are unsuitable because
the heat deflection temperature is not substantially improved by
adding glass fibers to such polymeric resins. Our results show
several critical parameters must be satisfied to provide a filled
resin which has the advantages of the instant invention. First, the
terephthalic acid component of the dicarboxylic acid mixture must
be present in a mole fraction (based on total dicarboxylic acid) of
0.65 or greater as revealed by Example VII, but this criterion in
and of itself is not sufficient as indicated by Example V (TA:IA of
65:35). A second requirement is that the mole ratio of isophthalic
acid to adipic acid must be less than 3 to 1. Example V does not
satisfy this second criterion, while the 75/15/10 composition of
Examples I and II and the 65/25/10 composition of Examples III and
IV do. These latter two formulations are the only two examples
cited which satisfy both criteria. On the other hand, Chapman, et
al, in U.S. Pat. No. 4,238,603, establish criteria for fiber
resins. The compositions of Examples V through VII are similar to
those cited in Example V, Table I of U.S. Pat. No. 4,238,603 as
compositions which provide dimensionally stable yarns. An
examination of the compositions prepared by Chapman, et al, reveals
that a mole ratio of isophthalic acid units to aliphatic diacid
units of three or greater is required in order to obtain a suitable
fiber.
It is well known to those skilled in the art that the strength
properties of conventional polyamides such as poly(hexamethylene
adipamide), i.e., Nylon 6,6, are adversely affected by moisture
absorbed from the environment. In Table V below, the effect of
moisture on several material properties including HDT at 264 psi,
are compared for a 30 wt. percent glass-fiber filled 65/25/10
(TA/IA/AA-HMDA) terpolyamide prepared as in Example III and a
commerical 33 wt. percent glass-filled Nylon 6,6.
TABLE V ______________________________________ The Effect of Water
on Polyamide Properties 30% Glass Filled 65/25/10 33% Glass Filled
(TA/IA/AA-HMDA) Nylon 6.6 Dry Equili- Dry Equili- as brium as brium
Molded Moisture Molded Moisture
______________________________________ HDT, .degree.F. 535 533 472
460 (ASTM D648) Flexural Modulus 1,300,000 1,310,000 1,170,000
540,000 Flexural Strength 39,000 32,500 39,200 20,100 (ASTM D790),
psi Tensile Strength 29,000 23,300 26,000 13,400 (ASTM D638), psi
Water Absorption 2.67 5.99 at Equilibrium, %
______________________________________
The 65/25/10 TA/IA/AA-HMDA) terpolymer resin of the instant
invention absorbs less moisture than Nylon 6,6 resin and is less
affected by moisture plasticization. The heat deflection
temperature and flexural modulus are virtually unaffected by
moisture. Moreover, 20% or less of the initial tensile and flexural
strengths are lost upon moisture plasticization. In contrast, the
heat deflection temperature of the glass-filled Nylon 6,6 drops to
460.degree. F., 60.degree. below that of the glass-filled
terpolyamide.
In the other strength properties, glass-filled Nylon 6,6 has lost
about one-half its strength by the time equilibrium moisture levels
are reached.
The following examples illustrate the use of other filler
materials. While improvements in HDT at 264 psi are not as great as
for glass filled compositions, improvements are still noted. These
filled compositions were prepared from 65/25/10-100 (TA/IA/AA-HMDA)
terpolymer prepared as in Example III. The compositions were either
dry blended and compounded before molding or, in some cases, the
dry blend itself was injection molded directly.
EXAMPLE VIII
In this example, mixtures of the standard glass fibers PPG 3450 and
glass beads were compounded with 65/25/10 (TA/IA/AA-HMDA)
terpolymer with an inherent viscosity of about 0.8 dl/g and
injection molded into a 250.degree. F. mold. The overall filler
level was held constant at 33 percent by weight.
______________________________________ Percent Glass Percent Glass
Fiber Beads HDT, .degree.F. ______________________________________
33 -- 501 31.3 1.7 432 29.7 3.3 452 24.7 8.3 429 -- -- 245
______________________________________
EXAMPLE IX
Forty weight percent of micro-mix beads alone were compounded with
65/25/10 (TA/IA/AA-HMDA) terpolymer. The heat deflection
temperature of 253.degree. F. was similar to the unfilled material
molded under the same conditions.
EXAMPLE X
Fibrous mineral fillers were compounded with the 65/25/10-100
(TA/IA/AA-HMDA) terpolymer.
______________________________________ Weight Filler Percent HDT,
.degree.F. ______________________________________ Wollastokup 40
355 Franklin Fiber 60 395 PMF 204 40 269
______________________________________
Improvements in heat deflection temperature were noted with
Wollastokup and Franklin Fiber.
EXAMPLE XI
A 65/25/10-100 (TA/IA/AA-HMDA) terpolymer prepared using procedure
A was dry blended with graphite fiber, Fortafil 3, and injection
molded. The resin used had an inherent viscosity of 1.26 dl/g, and
it was prepared by batch preparation procedure A. The heat
deflection temperatures showed little dependence on the filler
level. The results were:
______________________________________ Weight Percent Graphite
Fiber HDT, .degree.F. ______________________________________ 30 528
45 530 55 536 ______________________________________
EXAMPLE XII
A 75/15/10-100 (TA/IA/AA-HMDA) terpolymer prepared using procedure
A with an inherent viscosity of 1.16 dl/g was dry blended with
graphite fibers, Fortafil 3, and injection molded as above. The
heat deflection temperature again showed little dependence on the
filler level.
______________________________________ Weight Percent Graphite
Fiber HDT, .degree.F. ______________________________________ 30 570
45 >580 55 573 ______________________________________
These results are superior to those obtained with glass fibers of
similar levels of filler.
EXAMPLE XIII
A 75/15/10-100 (TA/IA/AA-HMDA) terpolymer prepared using procedure
A (IV=1.08 dl/g) was dry blended with a combination of 25 wt.
percent graphite fiber, Fortafil 3, and 25 wt. percent glass fiber,
and PPG 3531. When dry blend was injection molded into a
350.degree. F. mold, the heat deflection temperature was in excess
of 580.degree. F.
EXAMPLE XIV-A
These terpolymers can also be used as the matrix resin in
laminates. These laminates were prepared by compression molding
alternating layers of glass or graphite cloth with extruded films
of 65/25/10 (TA/IA/AA-HMDA) terpolymer. The 0.89 dl/g inherent
viscosity of a batch prepared sample of 65/25/10 terpolymer was
appreciated to 1.02 dl/g by reaction in ZSK-30 twin-screw extruder
reactor. A 3.5 mil film of this resin was then formed by extrusion
with a low compression screw at 675.degree. F. The composite was
formed by sandwiching.
EXAMPLE XIV-B
The compositions of this invention are suitable as matrix resins
for composites. Extruded films of 65/25/10-100 (TA/IA/AA-HMDA) were
laminated with glass or graphite cloth and compression molded in
order to obtain a composite. The matrix resin employed was a 7 ml
thick film extruded from a batch prepared 65/25/10-100
(TA/IA/AA-HMDA) terpolymer with an inherent viscosity of 1.03 dl/g.
The extruder used was a Brabender Plasticorder, Model EPL-V751, 3/4
inch extruder (L:D=25:1). The screw was a one stage, 2.4:1
compression screw. The die used was a 6 inch horizontal slit die
with an initial gap of 0.065 inches and a gap of 0.025 inches at
the exit. The average barrel and die temperatures were 340.degree.
C. The screw speed was 74 rpm.
A. Laminate of 65/25/10-100 (TA/IA/AA-HMDA) with Glass Cloth
A sandwich was made from thirteen layers of the 7 mil terpolymer
film which were alternated with twelve layers of glass cloth,
Uniglass 7781 Um 665. The layers were about 7 inches by 13 inches.
The sandwich was compression molded in a 50-ton press. The
composite was formed by heating the laminated sandwich under 100
psi until the indicated temperature was reached. The pressure was
then increased to the maximum indicated in the accompanying table.
The laminate was then maintained at the maximum temperature and
pressure for 1.5 minutes before cooling to about 400.degree. F. and
releasing the pressure. The flexural properties and horizontal
shear were determined for composites molded under various
conditions. The results were:
______________________________________ Flexural Horizontal
Compression molding strength modulus shear Temp. .degree.F. press,
psi M psi MM psi M psi ______________________________________ 630
300 95.0 4.2 9.3 640 300 99.5 3.9 10.3 640 400 97.4 3.9 10.4 650
300 98.7 4.4 8.2 ______________________________________
B. Laminate of 65/25/10-100 (TA/IA/AA-HMDA) with Graphite Cloth
The sandwich for this composite consisted of nne layers of the 7
mil film alternated with six layers of graphite cloth. The graphite
cloth was Hexcel F3T-584 which had been treated to remove the epoxy
surface coating. This thirteen layer sandwich was approximately 7
inches by 13 inches in size. The sandwich was formed into a
composite in much the same manner as described above except that
higher pressures were required to obtain good lamination.
______________________________________ Flexural Horizontal
Compression molding strength modulus shear Temp. .degree.F. press,
psi M psi MM psi M psi ______________________________________ 630
600 130 9.66 9.76 655 600 137 9.87 9.80
______________________________________
EXAMPLE XV
It is taught in U.S. Pat. No. 4,238,603 to form fibers directly
from the molten reaction mixture. Once formed, these fibers must be
heat treated to crystallize them. This crystallization provides the
fiber with the needed dimensional stability. Batch preparation has
several drawbacks. Most evident of these are the facts that (a) the
amount of fiber obtained depends directly on the size of the
reactor employed; (b) the distribution of residence times of molten
polymer in the reactor can lead to drastic changes in the
properties of the polymer with time; and (c) batch-to-batch
variations can be significant. In contrast, the resin of the
present invention can be formed into fiber by remelting solidified
polymer, typically in the form of pellets or granules, and
continuously forming said melt into a filament. Continuous filament
formation obviates the three problems cited above. Monofilaments
can be prepared as follows. The process starts with a single-screw
extruder to supply a melt for conversion to fiber. The monofilament
is drawn at a rate of about 50 to about 200 feet/minute. At the
slower draw speeds the monofilament is water quenched and
subsequently reheated and drawn with a heated drawing system. At
the higher melt spinning rates, the filament is drawn directly from
the melt with the aid of in-line heating ovens. The properties of a
65/25/10-100 (TA/IA/AA-HMDA) and monofilament prepared from a
340.degree. C. melt are presented in Table 6.
TABLE 6 ______________________________________ Initial Draw Ratio
Denier Elongation Tenacity Modulus X:1.0 g/9,000 m Percent g/d g/d
______________________________________ 4.4 650 9.2 4.0 56.0 5.2
1050 21.3 3.6 54.7 ______________________________________
EXAMPLE XVI
A series of terpolyamide/Nylon 6,6 blends were prepared. The Nylon
6,6 used was Zytel 101 from Du Pont Company.
The terpolyamide with a composition of 65/25/10-100 (TA/IA/AA-HMDA)
was prepared using procedure A. The I.V. of the terpolyamide was
1.02 dl/g. The glass fiber used was PPG 3540 from PPG Industries.
Blends of terpolyamide and Nylon 6,6 with and without glass fiber
reinforcement were made by dry mixing without extrusion
compounding. All materials were oven dried overnight before
molding. The test bars were injection molded. Physical testing was
carried out according to ASTM standard methods. Water absorption
was measured 24 hours after molding. The results are shown in the
table below.
TABLE 7
__________________________________________________________________________
MATERIAL PROPERTIES OF NYLON 6,6/TERPOLYAMIDE (TPA (65/25/10)
BLENDS Tensile Flexural Notched HDT Strength Elongation Strength
Modulus Izod (at 264 Water Nylon Glass ASTM Method ASTM Method ASTM
Method ASTM Method ASTM Absorp- TPA Fiber D638 D638 D790 D790 D256
METHOD tion Ratio Percent M psi Percent M psi MM psi ft-lb/in
.degree.F. Percent
__________________________________________________________________________
100/0 0 9.07* 72.5* 15.1 0.35 0.8 163 0.89 100/0 45 32.8 5.1 51.7
1.64 4.5 472 0.50 100/0 60 37.4 5.2 58.2 2.16 5.1 476 0.36 80/20 0
11.8 4.9 17.3 0.41 0.5 179 0.84 80/20 45 32.2 4.9 49.5 1.55 3.9 485
0.42 80/20 60 41.1 5.6 60.0 2.36 4.8 490 0.30 60/40 0 12.7 4.5 18.9
0.45 0.7 225 0.67 60/40 45 34.7 5.0 47.5 1.50 4.0 489 0.35 60/40 60
42.0 5.3 63.9 2.42 4.5 493 0.25 40/60 0 11.8 3.7 19.8 0.52 0.7 205
0.52 40/60 45 31.8 4.6 46.8 1.56 3.7 520 0.28 40/60 60 39.1 4.4
62.6 2.37 4.6 517 0.20 20/80 0 8.7 2.4 24.0 0.56 0.7 223 0.36 20/80
45 32.0 4.2 49.5 1.75 3.1 543 0.22 20/80 60 38.4 4.7 64.6 2.52 4.6
553 0.22 0/100 0 12.6 3.9 20.3 0.53 0.8 230 0.56 0/100 45 37.7 5.2
48.6 1.61 3.4 565 0.29 0/100 60 40.2 4.8 59.0 2.43 4.9 578 0.21
__________________________________________________________________________
*This sample had yield strength 10,500 psi, yield elongation 5.0
percent.
(TA/AA-HMDA Copolymers
Copolymers of hexamethylenediamine with adipic acid and
terephthalic acid are well known in the prior art, especially as
fibers for textile use. Incorporation of terephthalic acid into the
polymer improves the melt strength, an important consideration in
melt spinning, without adversely affecting the textile properties.
However, above a mole ratio of terephthalic acid to adipic acid of
about 0.18, the polymer melting point becomes too high to be useful
in melt spinning. Injection molding compositions of
hexamethylenediamine and terephthalic acid and adipic acid with a
TA/AA mole ratio of less than about 0.50 have mechanical properties
which are inferior to those of Nylon 6,6. The effect of composition
on the heat deflection temperature at 264 psi for various copolymer
compositions is presented in the Table below:
______________________________________ TA/AA mole ratio HDT,
.degree.F. ______________________________________ 0/100 (Nylon-6,6)
170 30/65 167 50/50 181 60/40 203 75/25 384
______________________________________
Poly(hexamethylene terephthalamide) melts with decomposition at
about 700.degree. F., and, as a result, it is not useful in
injection molding applications. In contrast, the filled polymers of
the instant invention in which the TA:AA mole ratio of 0.65 or
greater have an HDT in excess of glass-filled Nylon-6,6, and the
filled resins are less sensitive to moisture plasticization than is
Nylon-6,6. These features are illustrated by the resins prepared in
Examples XVII and XVIII. For comparison, a commerical Nylon-6,6
(DuPont Zytel 101) was dry blended with equivalent weights of glass
fiber and injection molded on the some molding machine under
similar conditions. These results are summarized in Table 8.
TABLE 8
__________________________________________________________________________
Tensile Flexural Strength Elongation Strength Modulus Notched Izod
HDT Water ASTM ASTM ASTM ASTM ASTM Tensile (at 264 Water TA/AA
Glass Immersion Method Method Method Method Method Impact ASTM
Absorp- Mole Fiber Time D638 D638 D790 D790 D256 Strength METHOD
tion Ratio Percent Hour M psi Percent M psi M psi ft-lb/in
ft-lb/in.sup.2 .degree.F. Percent
__________________________________________________________________________
0/100 0 0 11.9 12.8 17.5 397 0.9 95 155 24 9.2 277 15.5 276 1.4 90
165 1.38 1000 8.0 433 88.2 NB NB 146 6.7 30 0 26.0 4.6 51.2 1170
2.0 58 472 24 24.8 5.6 35.9 1000 2.6 87 469 0.87 1000 15.0 4.8 22.5
591 4.5 88 443 4.47 45 0 33.0 5.5 50.3 1840 3.4 97 493 24 32.1 5.8
46.3 1380 3.8 135 484 0.65 1000 20.9 4.9 29.1 954 5.0 118 480 3.31
60/40 0 0 12.9 4.1 20.4 475 0.8 32 203 24 11.2 3.7 19.6 437 0.7 43
211 0.63 1000 5.0 2.1 240 1.4 31 180 2.86 30 0 22.3 3.5 36.8 1310
1.6 30 563 24 19.8 3.2 32.3 1170 1.6 45 557 0.43 1000 17.3 3.2 20.1
862 1.6 46 550 2.27 45 0 34.0 4.6 50.6 1840 2.8 82 571 24 29.0 3.9
47.0 1760 2.9 93 576 0.33 1000 24.9 4.2 37.1 1320 2.5 99 567 1.70
75/25 0 0 12.1 3.3 23.1 55 0.8 38.1 24 30 0 24 45 0 31.9 4.3 464
1890 3.5 580 24
__________________________________________________________________________
EXAMPLE XVII
Batch Preparation of 60/40 (TA/AA-HMDA) Copolymer
7,238 grams of a solution of HMDA in water (70.8% HMDA), 4,250
grams of TA, 2,493 grams of AA, 11.85 grams of sodium
hypophosphite, 11.85 DC200 silicone oil as defoaming agent, and an
additional 1,678.9 grams of deionized water were loaded into the 10
CV Helicone reactor, which was preheated to about 170.degree. F.
After the loading, the melt temperature was slowly increased to
about 590.degree. F. in a period of about 108 minutes while the
agitator was running at about 40 rpm. The pressure in the reaction
increased to 120 psi and was controlled at about 10 psi as the melt
temperature increased. At the time, melt temperature reached
590.degree. F., the reactor pressure was vented down to atmosphere
pressure in a period of about 16 minutes. Then the polymer in the
reactor was dumped into water for cooling. The cooled polymer was
then ground, dried ion a vacuum oven at 220.degree. F. overnight,
and was ready for injection molding. The I.V. of this polymer was
0.90 dl/g.
EXAMPLE XVIII
Batch Preparation of 75/25 (TA/AA-HMDA) Copolymer
4,410 grams of a solution of hexamethylene diamine in water (70.8%
HMDA), 3,188 grams of terephthalic acid and 935 grams of adipic
acid were charged into a helicone mixer (model 10CV, Atlantic
Research Corp.), 3.6 grams of sodium hypophosphite was added as a
heat stabilizer and to increase the rate of reaction. 31 grams of
benzoic acid was added for molecular weight control. 7 grams of
silicone oil was added to reduce foaming. The helicone mixer was
sealed and the batch temperature was increased to 394.degree. F.
over a period of 80 minutes while stirring. The pressure increased
to 118 psig and was controlled at approximately 118 psig for 45
minutes while the batch temperature was increased to 497.degree. F.
At this point the pressure was reduced to 100 psig and controlled
at 100 psig for a period of 11 minutes. The pressure was then
reduced to atmospheric by venting over a period of three minutes.
The batch temperature was then 580.degree. F. The polymer was
removed from the mixer and quenched in water. The polymer was
ground, dried and fed into an extruder (Model ZSK30, Werner and
Pfleiderer) for further polycondensation. The resulting polymer had
an inherent viscosity of 1.06 dl/g.
* * * * *