U.S. patent application number 13/469918 was filed with the patent office on 2012-11-15 for amorphous polycarbonate films for capacitors, methods of manufacture, and articles manufactured therefrom.
Invention is credited to Gary Stephen Balch, Qin Chen, James Alan Mahood, Norberto Silvi.
Application Number | 20120287556 13/469918 |
Document ID | / |
Family ID | 46147761 |
Filed Date | 2012-11-15 |
United States Patent
Application |
20120287556 |
Kind Code |
A1 |
Silvi; Norberto ; et
al. |
November 15, 2012 |
AMORPHOUS POLYCARBONATE FILMS FOR CAPACITORS, METHODS OF
MANUFACTURE, AND ARTICLES MANUFACTURED THEREFROM
Abstract
A uniaxially-stretched, extruded film comprising a
polycarbonate, wherein the extruded film has at least one
wrinkle-free region having a first surface and a second surface,
the at least one extruded wrinkle-free region comprising: an
extruded thickness of more than 0 and less than 7 micrometer, and a
variation of the thickness of the film of +/-10% of the thickness
of the film, and a surface roughness average that is less than
+/-3% of the average thickness of the film as measured by optional
profilometery; and further wherein the film has a dielectric
constant at 1 kHz and room temperature of at least 2.7; a
dissipation factor at 1 kHz and room temperature of 1% or less; and
a breakdown strength of at least 300 Volt/micrometer.
Inventors: |
Silvi; Norberto; (Clifton
Park, NY) ; Chen; Qin; (Schnectady, CN) ;
Balch; Gary Stephen; (Ballston Spa, NY) ; Mahood;
James Alan; (Evansville, IN) |
Family ID: |
46147761 |
Appl. No.: |
13/469918 |
Filed: |
May 11, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61485305 |
May 12, 2011 |
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Current U.S.
Class: |
361/301.5 ;
428/141 |
Current CPC
Class: |
Y10T 428/24355 20150115;
H01G 4/18 20130101; C08J 5/18 20130101; H01B 3/426 20130101; H01G
4/008 20130101; H01G 4/32 20130101; C08J 2369/00 20130101 |
Class at
Publication: |
361/301.5 ;
428/141 |
International
Class: |
B32B 5/00 20060101
B32B005/00; H01G 4/32 20060101 H01G004/32 |
Claims
1. A uniaxially-stretched, extruded film comprising a
polycarbonate, wherein the film has at least one wrinkle-free
region having a first surface and a second surface, the at least
one extruded wrinkle-free region comprising: a thickness of more
than 0 and less than 7 micrometers, and a variation of the
thickness of the film of +/-10% or less of the thickness of the
film, and a surface roughness average of less than +/-3% of the
average thickness of the film as measured by optical profilometry;
and further wherein the film has: a dielectric constant at 1 kHz
and room temperature of at least 2.7; a dissipation factor at 1 kHz
and room temperature of 1% or less; and a breakdown strength of at
least 300 Volt/micrometer.
2. The film of claim 1, wherein the film has a length of at least
10 meter, and a width of at least 300 millimeter, and at least 80%
of the area of the film is the wrinkle-free region.
3. The film of claim 1, wherein the film has an energy density of
at least 3 J/cc.
4. The film of claim 2, wherein the film has a length of 100 to
10,000 meter, and a width of 300 to 3,000 millimeter.
5. The film of claim 1, wherein the film has less than 1,000 ppm of
a compound having a molecular weight of less than 250 Dalton.
6. The film of claim 1, wherein the film has less than 50 ppm each
of aluminum, calcium, magnesium, iron, nickel, potassium,
manganese, molybdenum, sodium, titanium, and zinc.
7. The film of claim 1, comprising less than 1000 ppm each of a
fluorine-containing compound or a silicone-containing compound.
8. The film of claim 1, comprising less than 100 ppm of a
fluorine-containing compound or a silicone-containing compound.
9. The film of claim 1, wherein the film has no observable specks
or gels over an area of at least 3 square meter when viewed at a
distance of 0.3 meter without magnification.
10. The film of claim 1, wherein the film has no observable voids
over an area of at least 3 square meter when viewed at a
magnification of 50.times..
11. The film of claim 1, wherein at least one of the surfaces of
the wrinkle-free region has a roughness value Ra of less than 3% of
the average thickness of the film.
12. The film of claim 1, wherein the polycarbonate is a
polycarbonate having repeating structural carbonate units of
formula (1) ##STR00013## in which at least 60 percent of the total
number of R.sup.1 groups contain aromatic moieties and the balance
thereof are aliphatic, alicyclic, or aromatic.
13. The film of claim 12, wherein the polycarbonate is a
homopolycarbonate derived from polymerization of a bisphenol
compound (3) ##STR00014## wherein R.sup.a and R.sup.b are each
independently a halogen atom or a monovalent hydrocarbon group; p
and q are each independently integers of 0 to 4; and X.sup.a is a
bridging group connecting the two hydroxy-substituted aromatic
groups, where the bridging group and the hydroxy substituent of
each C.sub.6 arylene group are disposed ortho, meta, or para
(specifically para) to each other on the C.sub.6 arylene group.
14. The film of claim 13, wherein each X.sup.a is independently
selected from a single bond, --O--, --S--, --S(O)--,
--S(O).sub.2--, --C(O)--, and a C.sub.1-18 organic group.
15. The film of claim 13, wherein each X.sup.a is independently
selected from a C.sub.1-18 alkylene group, a C.sub.3-18
cycloalkylene group, a fused C.sub.6-18 cycloalkylene group, a
group of the formula --B.sup.1--W--B.sup.2-- wherein B.sup.1 and
B.sup.2 are the same or different C.sub.1-6 alkylene group and W is
a C.sub.3-12 cycloalkylidene group or a C.sub.6-16 arylene group;
an alkyl-substituted bisphenol (4) ##STR00015## wherein R.sup.a'
and R.sup.b' are each independently C.sub.1-12 alkyl, R.sup.g is
C.sub.1-12 alkyl or halogen, r and s are each independently 1 to 4,
and t is 0 to 10; and a substituted C.sub.3-18 cycloalkylidene (5)
##STR00016## wherein R.sup.r, R.sup.p, R.sup.q, and R.sup.t are
independently hydrogen, halogen, oxygen, or C.sub.1-12 organic
groups; I is a direct bond, a carbon, or a divalent oxygen, sulfur,
or --N(Z)-- where Z is hydrogen, halogen, hydroxy, C.sub.1-12
alkyl, C.sub.1-12 alkoxy, or C.sub.1-12 acyl; h is 0 to 2, j is 1
or 2, i is an integer of 0 or 1, and k is an integer of 0 to 3,
with the proviso that at least two of R.sup.r, R.sup.p, R.sup.q,
and R.sup.t taken together are a fused cycloaliphatic, aromatic, or
heteroaromatic ring.
16. The film of claim 13, wherein the C.sub.1-18 organic bridging
group is --C(R.sup.c)(R.sup.d)-- or --C(.dbd.R.sup.e)--, wherein
R.sup.c and R.sup.d are each independently a hydrogen atom or a
monovalent C.sub.1-6 linear or cyclic hydrocarbon group and R.sup.e
is a divalent hydrocarbon group, p and q is each 0 or 1, and
R.sup.a and R.sup.b are each a C.sub.1-3 alkyl group
17. The film of claim 13, wherein the bisphenol compound (3) is
selected from 1,1-bis(4-hydroxyphenyl)methane,
1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl) propane,
2,2-bis(4-hydroxyphenyl) butane, 2,2-bis(4-hydroxyphenyl) octane,
1,1-bis(4-hydroxyphenyl) propane, 1,1-bis(4-hydroxyphenyl)
n-butane, 2,2-bis(4-hydroxy-2-methylphenyl) propane,
1,1-bis(4-hydroxy-t-butylphenyl) propane, 3,3-bis(4-hydroxyphenyl)
phthalimidine, 2-phenyl-3,3-bis(4-hydroxyphenyl) phthalimidine, and
1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane.
18. The film of claim 12, wherein the polycarbonate is a
homopolymer.
19. The film of claim 12, wherein the polycarbonate is
copolycarbonate comprising at least two different R.sup.1
moieties.
20. The film of claim 12, wherein the polycarbonate is a
polycarbonate copolymer comprising a repeating carbonate unit (1),
and a repeating unit selected from ester units, diorganosiloxane
units, urethane units, arylene ether units, arylene sulfone units,
arylene ketone units, and combinations thereof.
21. The film of claim 20 wherein the polycarbonate is a
poly(carbonate-ester) comprising repeating carbonate units (1), and
repeating ester units (7) ##STR00017## wherein J is selected from a
C.sub.2-10 alkylene group, a C.sub.6-20 alicyclic group, a
C.sub.6-20 aromatic group, and a polyoxyalkylene group in which the
alkylene groups contain 2 to 6 carbon atoms, specifically 2, 3, or
4 carbon atoms; and T is selected from a C.sub.2-10 alkylene group,
a C.sub.6-20 alicyclic group, a C.sub.6-20 alkyl aromatic group, or
a C.sub.6-20 aromatic group.
22. The film of claim 21, wherein the poly(carbonate-ester)
comprises repeating aromatic carbonate-ester units (8) ##STR00018##
wherein Ar is divalent aromatic residue of a dicarboxylic acid or
combination of dicarboxylic acids, and Ar' is a divalent aromatic
residue of (a) a bisphenol (3) ##STR00019## wherein R.sup.a and
R.sup.b are each independently a halogen atom or a monovalent
hydrocarbon group; p and q are each independently integers of 0 to
4; and X.sup.a is a bridging group connecting the two
hydroxy-substituted aromatic groups, where the bridging group and
the hydroxy substituent of each C.sub.6 arylene group are disposed
ortho, meta, or para (specifically para) to each other on the
C.sub.6 arylene group, or (b) an aromatic dihydric compound (6)
##STR00020## wherein each R.sup.h is independently a halogen atom,
a C.sub.1-10 hydrocarbyl group, a halogen-substituted C.sub.1-10
alkyl group, a C.sub.6-10 aryl group, or a halogen-substituted
C.sub.6-10 aryl group, and n is 0 to 4; and x is 20 to less than
100 and y is more than 0 to 80, wherein x and y are in parts by
weight based on 100 parts by weight of the
poly(carbonate-ester).
23. The film of claim 22, wherein Ar is the residue of isophthalic
acid (9a), terephthalic acid (9b), ##STR00021## or a combination
thereof.
24. The film of claim 23, wherein Ar' is the residue of bisphenol
A.
25. The film of claim 21, wherein the polycarbonate is a
poly(carbonate-ester) comprising repeating carbonate units (1)
derived from a bisphenol (3) ##STR00022## wherein R.sup.a and
R.sup.b are each independently a halogen atom or a monovalent
hydrocarbon group; p and q are each independently integers of 0 to
4; and X.sup.a is a bridging group connecting the two
hydroxy-substituted aromatic groups, where the bridging group and
the hydroxy substituent of each C.sub.6 arylene group are disposed
ortho, meta, or para (specifically para) to each other on the
C.sub.6 arylene group; and repeating arylate ester units (9)
##STR00023## wherein each R.sup.4 is independently a halogen or a
C.sub.1-4 alkyl, and p is 0 to 3.
26. The film of claim 25, wherein the ester units are
poly(isophthalate-terephthalate-resorcinol ester) units.
27. The film of claim 26, wherein the bisphenol (3) is bisphenol
A.
28. The film of claim 25, wherein the poly(carbonate-ester) further
comprises repeating carbonate units (1) derived from an aromatic
dihydric compound (6) ##STR00024## wherein each R.sup.4 is
independently a halogen or a C.sub.1-4 alkyl, and n is 0 to 3; and
wherein the molar ratio of carbonate units derived from bisphenol
(3) to carbonate units derived from dihydroxy compound (6) is 1:99
to 99:1.
29. The film of claim 28, wherein the ester units are
poly(isophthalate-terephthalate-resorcinol ester) units.
30. The film of claim 29, wherein the poly(carbonate-ester) is a
poly(bisphenol-A carbonate)-co-(resorcinol
carbonate)-co(isophthalate-terephthalate-resorcinol ester).
31. The film of claim 19, wherein the polycarbonate is a
poly(carbonate-siloxane) comprising repeating carbonate units (1);
and repeating diorganosiloxane units (10) ##STR00025## wherein each
R is independently the same or different C.sub.1-13 monovalent
organic group; and E has an average value of 5 to 200.
32. The film of claim 31, wherein the polysiloxane units are of
formula (13): ##STR00026## wherein each R is independently the same
or different C.sub.1-13 monovalent organic group; E has an average
value of 5 to 65; R.sup.6 is a divalent C.sub.2-C.sub.8 aliphatic
group; each M is independently a halogen, cyano, nitro,
C.sub.1-C.sub.8 alkylthio, C.sub.1-C.sub.8 alkyl, C.sub.1-C.sub.8
alkoxy, C.sub.2-C.sub.8 alkenyl, C.sub.2-C.sub.8 alkenyloxy group,
C.sub.3-C.sub.8 cycloalkyl, C.sub.3-C.sub.8 cycloalkoxy,
C.sub.6-C.sub.10 aryl, C.sub.6-C.sub.10 aryloxy, C.sub.7-C.sub.12
aralkyl, C.sub.7-C.sub.12 aralkoxy, C.sub.7-C.sub.12 alkylaryl, or
C.sub.7-C.sub.12 alkylaryloxy; and each n is independently 0, 1, 2,
3, or 4.
33. The film of claim 32, wherein in the carbonate units, R.sup.1
is derived from bisphenol A; and in the siloxane units, M is
methoxy, n is one, R.sup.2 is a divalent C.sub.1-C.sub.3 aliphatic
group, and R is methyl.
34. The film of claim 19, wherein the polycarbonate is a
polycarbonate-ester-siloxane) comprising repeating carbonate units
(1); repeating siloxane units (10) ##STR00027## wherein each R is
independently the same or different C.sub.1-13 monovalent organic
group; and E has an average value of 5 to 200; and repeating ester
units (7) ##STR00028## wherein J is selected from a C.sub.2-10
alkylene group, a C.sub.6-20 alicyclic group, a C.sub.6-20 aromatic
group, and a polyoxyalkylene group in which the alkylene groups
contain 2 to 6 carbon atoms, specifically 2, 3, or 4 carbon atoms;
and T is selected from a C.sub.2-10 alkylene group, a C.sub.6-20
alicyclic group, a C.sub.6-20 alkyl aromatic group, or a C.sub.6-20
aromatic group.
35. The film of claim 3, wherein in the polycarbonate units,
R.sup.1 is derived from a bisphenol A; the siloxane units are
polysiloxane blocks (13): ##STR00029## wherein each R is
independently the same or different C.sub.1-13 monovalent organic
group; E has an average value of 5 to 65; R.sup.6 is a divalent
C.sub.2-C.sub.8 aliphatic group; each M is independently a halogen,
cyano, nitro, C.sub.1-C.sub.8 alkylthio, C.sub.1-C.sub.8 alkyl,
C.sub.1-C.sub.8 alkoxy, C.sub.2-C.sub.8 alkenyl, C.sub.2-C.sub.8
alkenyloxy group, C.sub.3-C.sub.8 cycloalkyl, C.sub.3-C.sub.8
cycloalkoxy, C.sub.6-C.sub.10 aryl, C.sub.6-C.sub.10 aryloxy,
C.sub.7-C.sub.12 aralkyl, C.sub.7-C.sub.12 aralkoxy,
C.sub.7-C.sub.12 alkylaryl, or C.sub.7-C.sub.12 alkylaryloxy; and
each n is independently 0, 1, 2, 3, or 4; and the ester units are
of formula (9) ##STR00030## wherein each R.sup.4 is independently a
halogen or a C.sub.1-4 alkyl, and p is 0 to 3.
36. The film of claim 34, wherein in the carbonate units, R.sup.1
is derived from bisphenol A; in the polysiloxane blocks, M is
methoxy, n is one, R.sup.2 is a divalent C.sub.1-C.sub.3 aliphatic
group, and R is methyl; and the ester units are
(isophthalate-terephthalate-resorcinol) ester units
37. An article comprising the film of claim 1.
38. The article of claim 37, further comprising a layer of a
conductive metal deposited on at least a portion of the
wrinkle-free region.
39. The article of claim 38, wherein the conductive metal comprises
aluminum, zinc, copper, or a combination thereof.
40. The article of claim 39, wherein the conductive metal layer has
a thickness of 1 to 3000 Angstroms.
41. The article of claim 40, wherein the conductive metal layer has
a thickness of 1 to 2000 Angstroms.
42. The article of claim 41, wherein the conductive metal layer has
a resistivity of 0.1 to 100 Ohm/sq.
43. The article of claim 38, wherein the conductive metal layer is
deposited by chemical vapor deposition, high temperature vacuum
operations, or combinations thereof.
44. A capacitor comprising a wound, metallized film of claim
37.
45. An electronic article comprising the capacitor of claim 44.
46. The film of claim 1 wound on a roll, wherein the roll has no
observable wrinkles or die lines when viewed without magnification
at a distance of 0.3 meter.
47. An article comprising a portion of the film of claim 46.
48. The article of claim 47, further comprising a layer of a
conductive metal deposited on at least a portion of the surface of
the wrinkle-free region.
49. The article of claim 48, wherein the conductive metal comprises
aluminum, zinc, copper, or a combination thereof.
50. The article of claim 49, wherein the conductive metal layer has
a thickness of 1 to 1000 angstrom.
51. The article of claim 50, wherein the conductive metal layer has
a resistivity of 0.1 to 100 Ohm/sq.
52. The article of claim 48, wherein the conductive metal layer is
deposited by chemical vapor deposition, high temperature vacuum
operations, or combinations thereof.
53. A capacitor comprising a wound metallized film of claim 46.
54. An electronic article comprising the capacitor of claim 53.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 61/485,305 filed May 12, 2011. The
related application is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] This disclosure relates to polymer films, and in particular
to amorphous polymer films useful for the manufacture of
capacitors.
[0003] Electrostatic film capacitors with high volumetric energy
density, high operating temperature, and long lifetime are critical
components for pulse-power, automotive, and industrial electronics.
Capacitors are essentially energy-storing devices having two
parallel conductive plates separated by a thin layer of an
insulating (dielectric) film. When a voltage is applied across the
plates, the electric field in the dielectric displaces electric
charges, and thus stores energy. The amount of energy stored by a
capacitor depends on the dielectric constant and breakdown voltage
of the insulating material, and the dimensions (total area and
thickness) of the film, such that in order to maximize the total
amount of energy that a capacitor can accumulate, the dielectric
constant and breakdown voltage of the film are maximized, and the
thickness of the film minimized. Because the physical
characteristics of the dielectric material in the capacitor are the
primary determining factors for the performance of a capacitor,
improvements in one or more of the physical properties of the
dielectric material in a capacitor can result in corresponding
performance improvements in the capacitor component, usually
resulting in performance and lifetime enhancements of the
electronics system or product in which it is embedded.
[0004] Electrostatic film capacitors made from biaxially-oriented
poly(propylene) (BOPP) have been used in applications requiring a
low dissipation factor, high insulation resistance and low
dielectric absorption, such as in electrical appliances, electronic
equipment, oven and furnaces, refrigerators, automobiles, and home
appliances. The low dielectric constant (Dk), which is about 2.2,
and the maximum service temperature of about 100.degree. C., limits
the use of these capacitors in applications requiring high
operating temperatures and/or high energy densities.
Poly(carbonate) (also known as polycarbonate, or PC) films have a
higher dielectric constant than BOPP films (about 3.0) and a higher
maximum service temperature of about 125.degree. C.
[0005] There accordingly remains a need in the art for new films
and methods for their manufacture that can produce films of very
high purity and with excellent electrical properties, in particular
high breakdown strength, and high dielectric constant. It would be
a further advantage if such films could operate at higher
temperature than BOPP films. There remains a further need for
efficient methods for producing such films that are amendable to
industrial scale processes. It would be further advantage if such
methods were environmentally friendly.
SUMMARY OF THE INVENTION
[0006] The invention relates to a uniaxially-stretched, extruded
film comprising a polycarbonate, wherein the film has at least one
wrinkle-free region having a first surface and a second surface,
the at least one extruded wrinkle-free region comprising: a
thickness of more than 0 and less than 7 micrometers, and a
variation of the thickness of the film of +/-10% or less of the
thickness of the film, and a surface roughness average of less than
+/-3% of the average thickness of the film as measured by optical
profilometry; and further wherein the film has: a dielectric
constant at 1 kHz and room temperature of at least 2.7; a
dissipation factor at 1 kHz and room temperature of 1% or less; and
a breakdown strength of at least 300 Volts/micrometer.
[0007] Articles comprising the above compositions are also
disclosed.
[0008] In another embodiment, our invention relates to metallized
uniaxially-stretched, extruded films.
[0009] In another embodiment, our invention relates to capacitors
made from metallized uniaxially-stretched, extruded films.
[0010] In another embodiment, our invention relates to an
electronic article comprising the capacitors made from wound
metallized uniaxially-stretched extruded film.
DETAILED DESCRIPTION OF THE INVENTION
[0011] The present inventors have discovered that polycarbonate
substrate films for electrostatic capacitors having excellent
properties can be manufactured in a solventless process by
extrusion. In a surprising and important feature, the extruded
films can have large wrinkle-free regions having a breakdown
strength of at least 300 Volts/micrometer. The wrinkle-free regions
are sufficiently smooth and flat such that the substrate film can
be metallized to provide a metallized film of substantially uniform
breakdown strength across the region.
[0012] In particular, the wrinkle-free regions have a thickness of
more than 0 and less than 7 micrometers, where any variation of the
thickness of the film is .+-.10% of the average thickness of the
film, and the surface roughness of the film is less than 3% of the
average thickness of the film. The films provide both an increase
in the capacitor dielectric constant and dielectric breakdown
strength compared to prior art films, while retaining other
advantageous physical and electrical characteristics, such as
flexibility, thinness, and dielectric constant stability. In
particular, the films can have a high voltage breakdown strength
(at least 300 Volts/micrometer), a high dielectric constant
(greater than 2.7), and a low dissipation factor (less than 1%).
The films and capacitors made from the films accordingly offer
advantages over current materials and methods for the manufacture
of components for the electronics industry. A particular advantage
is that the films can be reliably manufactured on an industrial
scale in a solventless process. Removal of solvent from
solvent-cast films can be difficult. The extruded films herein are
processed without solvent, providing both a cost and a
manufacturing advantage. In another embodiment, the extruded films
are more than 0 and less than or equal to 13 microns.
[0013] Various numerical ranges are disclosed in this patent
application. Because these ranges are continuous, they include
every value between the minimum and maximum values. Unless
expressly indicated otherwise, the various numerical ranges
specified in this application are approximations. The endpoints of
all ranges directed to the same component or property are inclusive
of the endpoint and independently combinable.
[0014] All molecular weights in this application refer to weight
average molecular weights unless indicated otherwise. All such
mentioned molecular weights are expressed in Daltons.
[0015] The terms "a" and "an" do not denote a limitation of
quantity, but rather denote the presence of at least one of the
referenced items. As used herein, "combination thereof" is
inclusive of one or more of the recited elements, optionally
together with a like element not recited. Reference throughout the
specification to "an embodiment," "another embodiment," "an
embodiment," "some embodiments," and so forth, means that a
particular element (e.g., feature, structure, property, and/or
characteristic) described in connection with the embodiment is
included in at least an embodiment described herein, and can or
cannot be present in other embodiments. In addition, it is to be
understood that the described element(s) can be combined in any
suitable manner in the various embodiments.
[0016] Compounds are described using standard nomenclature. For
example, any position not substituted by any indicated group is
understood to have its valency filled by a bond as indicated, or a
hydrogen atom. A dash ("-") that is not between two letters or
symbols is used to indicate a point of attachment for a
substituent. For example, --CHO is attached through carbon of the
carbonyl group. The term "alkyl" includes both C.sub.1-30 branched
and straight chain, unsaturated aliphatic hydrocarbon groups having
the specified number of carbon atoms. Examples of alkyl include,
but are not limited to, methyl, ethyl, n-propyl, i-propyl, n-butyl,
s-butyl, t-butyl, n-pentyl, s-pentyl, n- and s-hexyl, n- and
s-heptyl, and, n- and s-octyl. The term "aryl" means an aromatic
moiety containing the specified number of carbon atoms, such as to
phenyl, tropone, indanyl, or naphthyl.
[0017] All ASTM tests are based on the 2003 edition of the Annual
Book of ASTM Standards unless otherwise indicated.
[0018] The polycarbonate can be a polycarbonate homopolymer or a
polycarbonate copolymer as further described below. Polycarbonates
are polymers having repeating structural carbonate units (1)
##STR00001##
in which at least 60 percent of the total number of R.sup.1 groups
contain aromatic moieties and the balance thereof are aliphatic,
alicyclic, or aromatic. In an embodiment, each R.sup.1 is a
C.sub.6-30 aromatic group, that is, contains at least one aromatic
moiety. R.sup.1 can be derived from an aromatic dihydroxy compound
of the formula HO--R.sup.1--OH, in particular (2)
HO-A.sup.1-Y.sup.1-A.sup.2-OH (2)
wherein each of A.sup.1 and A.sup.2 is a monocyclic divalent
aromatic group and Y.sup.1 is a single bond or a bridging group
having one or more atoms that separate A.sup.1 from A.sup.2. In an
exemplary embodiment, one atom separates A.sup.1 from A.sup.2. Also
included are bisphenol compounds (3)
##STR00002##
wherein R.sup.a and R.sup.b are each independently a halogen atom
or a monovalent hydrocarbon group and may be the same or different;
p and q are each independently integers of 0 to 4; and X.sup.a is a
bridging group connecting the two hydroxy-substituted aromatic
groups, where the bridging group and the hydroxy substituent of
each C.sub.6 arylene group are disposed ortho, meta, or para
(specifically para) to each other on the C.sub.6 arylene group. In
an embodiment, the bridging group X.sup.a is a single bond, --O--,
--S--, --S(O)--, --S(O).sub.2--, --C(O)--, or a C.sub.1-18 organic
group. The C.sub.1-18 organic bridging group can be cyclic or
acyclic, aromatic or non-aromatic, and can further comprise
heteroatoms such as a halogen, oxygen, nitrogen, sulfur, silicon,
or phosphorous. The C.sub.1-18 organic group can be disposed such
that the C.sub.6 arylene groups connected thereto are each
connected to a common alkylidene carbon or to different carbons of
the C.sub.1-18 organic bridging group. In particular, X.sup.a is a
C.sub.1-18 alkylene group, a C.sub.3-18 cycloalkylene group, a
fused C.sub.6-18 cycloalkylene group, or a group of the formula
--B.sup.1--W--B.sup.2-- wherein B.sup.1 and B.sup.2 are the same or
different C.sub.1-6 alkylene group and W is a C.sub.3-12
cycloalkylidene group or a C.sub.6-16 arylene group.
[0019] Exemplary C.sub.1-18 organic bridging groups include
methylene, cyclohexylmethylene, ethylidene, neopentylidene, and
isopropylidene, as well as 2-[2.2.1]-bicycloheptylidene and
cycloalkylidenes such as cyclohexylidene, cyclopentylidene,
cyclododecylidene, and adamantylidene. A specific example of
bisphenol (3) wherein X.sup.a is a substituted cycloalkylidene is
the cyclohexylidene-bridged, alkyl-substituted bisphenol (4)
##STR00003##
wherein R.sup.a' and R.sup.b' are each independently C.sub.1-12
alkyl, R.sup.g is C.sub.1-12 alkyl or halogen, r and s are each
independently 1 to 4, and t is 0 to 10. In a specific embodiment,
at least one of each of R.sup.a' and R.sup.b' is disposed meta to
the cyclohexylidene bridging group. The substituents R.sup.a',
R.sup.b', and R.sup.g can, when comprising an appropriate number of
carbon atoms, be a straight chain, cyclic, bicyclic, branched,
saturated, or unsaturated. In an embodiment, R.sup.a' and R.sup.b'
are each independently C.sub.1-4 alkyl, R.sup.g is C.sub.1-4 alkyl,
r and s are each 1, and t is 0 to 5. In another specific
embodiment, R.sup.a', R.sup.b' and R.sup.g are each methyl, r and s
are each 1, and t is 0 or 3. In another exemplary embodiment, the
cyclohexylidene-bridged bisphenol is the reaction product of two
moles of a cresol with one mole of a hydrogenated isophorone (e.g.,
1,1,3-trimethyl-3-cyclohexane-5-one).
[0020] X.sup.a in bisphenol (3) can also be a substituted
C.sub.3-18 cycloalkylidene (5)
##STR00004##
wherein R.sup.r, R.sup.p, R.sup.q, and R.sup.t are independently
hydrogen, halogen, oxygen, or C.sub.1-12 organic groups; I is a
direct bond, a carbon, or a divalent oxygen, sulfur, or --N(Z)--
where Z is hydrogen, halogen, hydroxy, C.sub.1-12 alkyl, C.sub.1-12
alkoxy, or C.sub.1-12 acyl; h is 0 to 2, j is 1 or 2, i is an
integer of 0 or 1, and k is an integer of 0 to 3, with the proviso
that at least two of R.sup.r, R.sup.p, R.sup.q, and R.sup.t taken
together are a fused cycloaliphatic, aromatic, or heteroaromatic
ring. It will be understood that when the fused ring is aromatic,
the ring as shown in formula (5) will have an unsaturated
carbon-carbon linkage where the ring is fused. When k is one and i
is 0, the ring as shown in formula (5) contains 4 carbon atoms,
when k is 2, the ring as shown in formula (5) contains 5 carbon
atoms, and when k is 3, the ring contains 6 carbon atoms. In an
embodiment, two adjacent groups (e.g., R.sup.q and R.sup.t taken
together) form an aromatic group, and in another embodiment,
R.sup.q and R.sup.t taken together form one aromatic group and
R.sup.r and R.sup.p taken together form a second aromatic group.
When R.sup.q and R.sup.t taken together form an aromatic group,
R.sup.p can be a double-bonded oxygen atom, i.e., a ketone.
[0021] In another specific embodiment of the bisphenol compound
(3), the C.sub.1-18 organic bridging group includes groups
--C(R.sup.c)(R.sup.d)-- or --C(.dbd.R.sup.e)--, wherein R.sup.c and
R.sup.d are each independently a hydrogen atom or a monovalent
C.sub.1-6 linear or cyclic hydrocarbon group and R.sup.e is a
divalent hydrocarbon group, p and q is each 0 or 1, and R.sup.a and
R.sup.b are each a C.sub.1-3 alkyl group, specifically methyl,
disposed meta to the hydroxy group on each arylene group.
[0022] Other useful aromatic dihydroxy compounds of the formula
HO--R.sup.1--OH include aromatic dihydric compounds (6)
##STR00005##
wherein each R.sup.h is independently a halogen atom, a C.sub.1-10
hydrocarbyl such as a C.sub.1-10 alkyl group, a halogen-substituted
C.sub.1-10 alkyl group, a C.sub.6-10 aryl group, or a
halogen-substituted C.sub.6-10 aryl group, and n is 0 to 4. The
halogen is usually bromine.
[0023] Some illustrative examples of specific aromatic dihydroxy
compounds include the following: 4,4'-dihydroxybiphenyl,
1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene,
bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)diphenylmethane,
bis(4-hydroxyphenyl)-1-naphthylmethane,
1,2-bis(4-hydroxyphenyl)ethane,
1,1-bis(4-hydroxyphenyl)-1-phenylethane,
2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane,
bis(4-hydroxyphenyl)phenylmethane,
2,2-bis(4-hydroxy-3-bromophenyl)propane, 1,1-bis
(hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane,
1,1-bis(4-hydroxyphenyl)isobutene,
1,1-bis(4-hydroxyphenyl)cyclododecane,
trans-2,3-bis(4-hydroxyphenyl)-2-butene,
2,2-bis(4-hydroxyphenyl)adamantane, alpha,
alpha'-bis(4-hydroxyphenyl)toluene,
bis(4-hydroxyphenyl)acetonitrile,
2,2-bis(3-methyl-4-hydroxyphenyl)propane,
2,2-bis(3-ethyl-4-hydroxyphenyl)propane,
2,2-bis(3-n-propyl-4-hydroxyphenyl)propane,
2,2-bis(3-isopropyl-4-hydroxyphenyl)propane,
2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane,
2,2-bis(3-t-butyl-4-hydroxyphenyl)propane,
2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane,
2,2-bis(3-allyl-4-hydroxyphenyl)propane,
2,2-bis(3-methoxy-4-hydroxyphenyl)propane,
2,2-bis(4-hydroxyphenyl)hexafluoropropane,
1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene,
1,1-dibromo-2,2-bis(4-hydroxyphenyl)ethylene,
1,1-dichloro-2,2-bis(5-phenoxy-4-hydroxyphenyl)ethylene,
4,4'-dihydroxybenzophenone, 3,3-bis(4-hydroxyphenyl)-2-butanone,
1,6-bis(4-hydroxyphenyl)-1,6-hexanedione, ethylene glycol
bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)ether,
bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide,
bis(4-hydroxyphenyl)sulfone, 9,9-bis(4-hydroxyphenyl)fluorine,
2,7-dihydroxypyrene,
6,6'-dihydroxy-3,3,3',3'-tetramethylspiro(bis)indane
("spirobiindane bisphenol"), 3,3-bis(4-hydroxyphenyl)phthalimide,
2,6-dihydroxydibenzo-p-dioxin, 2,6-dihydroxythianthrene,
2,7-dihydroxyphenoxathin, 2,7-dihydroxy-9,10-dimethylphenazine,
3,6-dihydroxydibenzofuran, 3,6-dihydroxydibenzothiophene, and
2,7-dihydroxycarbazole, resorcinol, substituted resorcinol
compounds such as 5-methyl resorcinol, 5-ethyl resorcinol, 5-propyl
resorcinol, 5-butyl resorcinol, 5-t-butyl resorcinol, 5-phenyl
resorcinol, 5-cumyl resorcinol, 2,4,5,6-tetrafluoro resorcinol,
2,4,5,6-tetrabromo resorcinol, or the like; catechol; hydroquinone;
substituted hydroquinones such as 2-methyl hydroquinone, 2-ethyl
hydroquinone, 2-propyl hydroquinone, 2-butyl hydroquinone,
2-t-butyl hydroquinone, 2-phenyl hydroquinone, 2-cumyl
hydroquinone, 2,3,5,6-tetramethyl hydroquinone,
2,3,5,6-tetra-t-butyl hydroquinone, 2,3,5,6-tetrafluoro
hydroquinone, 2,3,5,6-tetrabromo hydroquinone, or the like, or
combinations comprising at least one of the foregoing dihydroxy
compounds.
[0024] Specific examples of bisphenol compounds (3) include
1,1-bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane,
2,2-bis(4-hydroxyphenyl) propane (also known as "bisphenol A" or
"BPA"), 2,2-bis(4-hydroxyphenyl) butane, 2,2-bis(4-hydroxyphenyl)
octane, 1,1-bis(4-hydroxyphenyl) propane, 1,1-bis(4-hydroxyphenyl)
n-butane, 2,2-bis(4-hydroxy-2-methylphenyl) propane,
1,1-bis(4-hydroxy-t-butylphenyl) propane, 3,3-bis(4-hydroxyphenyl)
phthalimidine, 2-phenyl-3,3-bis(4-hydroxyphenyl) phthalimidine
(PPPBP), and 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane (DMBPC).
Combinations comprising at least one of the foregoing dihydroxy
compounds can also be used. In one specific embodiment, the
polycarbonate is a linear homopolymer derived from bisphenol A, in
which each of A.sup.1 and A.sup.2 is p-phenylene and Y.sup.1 is
isopropylidene in formula (13).
[0025] "Polycarbonate" as used herein includes homopolycarbonates
(wherein each R.sup.1 in the polymer is the same), copolymers
comprising different R.sup.1 moieties in the carbonate units
(referred to herein as "copolycarbonates"), copolymers comprising
carbonate units and other types of polymer units (such as ester
units, diorganosiloxane units, urethane units, arylene ether units,
arylene sulfone units, arylene ketone units, and combinations
thereof), and combinations of at least one homopolycarbonate and/or
at least one copolycarbonate and/or at least one polycarbonate
copolymer. As used herein, a "combination" is inclusive of blends,
mixtures, alloys, reaction products, and the like.
[0026] A specific polycarbonate copolymer is a
poly(carbonate-ester). Such copolymers further contain, in addition
to repeating carbonate units (1), repeating ester units (7)
##STR00006##
wherein J is a divalent group derived from a dihydroxy compound,
and can be, for example, a C.sub.2-10 alkylene group, a C.sub.6-20
alicyclic group, a C.sub.6-20 aromatic group or a polyoxyalkylene
group in which the alkylene groups contain 2 to 6 carbon atoms,
specifically 2, 3, or 4 carbon atoms; and T divalent group derived
from a dicarboxylic acid, and can be, for example, a C.sub.2-10
alkylene group, a C.sub.6-20 alicyclic group, a C.sub.6-20 alkyl
aromatic group, or a C.sub.6-20 aromatic group.
Poly(carbonate-ester)s containing a combination of different T
and/or J groups can be used. The poly(carbonate-ester)s can be
branched or linear.
[0027] In an embodiment, J is a C.sub.2-30 alkylene group having a
straight chain, branched chain, or cyclic (including polycyclic)
structure. In another embodiment, J is derived from an aromatic
dihydroxy compound (3). In another embodiment, J is derived from an
aromatic dihydroxy compound (4). In another embodiment, J is
derived from an aromatic dihydroxy compound (6).
[0028] Exemplary aromatic dicarboxylic acids that can be used to
prepare the polyester units include isophthalic or terephthalic
acid, 1,2-di(p-carboxyphenyl)ethane, 4,4'-dicarboxydiphenyl ether,
4,4'-bisbenzoic acid, or a combination comprising at least one of
the foregoing acids. Acids containing fused rings can also be
present, such as in 1,4-, 1,5-, or 2,6-naphthalenedicarboxylic
acids. Specific dicarboxylic acids include terephthalic acid,
isophthalic acid, naphthalene dicarboxylic acid, cyclohexane
dicarboxylic acid, or a combination comprising at least one of the
foregoing acids. A specific dicarboxylic acid comprises a
combination of isophthalic acid and terephthalic acid wherein the
weight ratio of isophthalic acid to terephthalic acid is 91:9 to
2:98. In another specific embodiment, J is a C.sub.2-6 alkylene
group and T is p-phenylene, m-phenylene, naphthalene, a divalent
cycloaliphatic group, or a combination thereof.
[0029] The molar ratio of carbonate units to ester units in the
copolymers can vary broadly, for example 1:99 to 99:1, specifically
10:90 to 90:10, more specifically 25:75 to 75:25, depending on the
desired properties of the final composition.
[0030] A specific embodiment of a poly(carbonate-ester) (8)
comprises repeating aromatic carbonate and aromatic ester units
##STR00007##
wherein Ar is divalent aromatic residue of a dicarboxylic acid or
combination of dicarboxylic acids, and Ar' is a divalent aromatic
residue of a bisphenol (3) or a dihydric compound (6). Ar is thus
an aryl group, and is preferably the residue of isophthalic acid
(9a), terephthalic acid (9b),
##STR00008##
or a combination thereof. Ar' may be polycyclic, e.g., a residue of
biphenol or bisphenol A, or monocyclic, e.g., the residue of
hydroquinone or resorcinol.
[0031] Further in the poly(carbonate-ester) (8), x and y represent
the respective parts by weight of the aromatic ester units and the
aromatic carbonate units based on 100 parts total weight of the
copolymer. Specifically, x, the aromatic ester content, is 20 to
less than 100 wt. %, specifically 30 to 95 wt. %, still more
specifically 50 to 95 wt. %, and y, the carbonate content, is from
more than zero to 80 wt. %, from 5 to 70 wt. %, still more
specifically from 5 to 50 wt. %, each based on the total weight of
units x+y. In general, any aromatic dicarboxylic acid
conventionally used in the preparation of polyesters may be
utilized in the preparation of poly(carbonate-ester)s (8) but
terephthalic acid alone can be used, or mixtures thereof with
isophthalic acid wherein the weight ratio of terephthalic acid to
isophthalic acid is in the range of from 5:95 to 95:5.
Poly(carbonate-ester)s (8) comprising 35 to 45 wt. % of carbonate
units and 55 to 65 wt. % of ester units, wherein the ester units
have a molar ratio of isophthalate to terephthalate of 45:55 to
55:45 are often referred to as poly(carbonate-ester)s (PCE) and
copolymers comprising 15 to 25 wt. % of carbonate units and 75 to
85 wt. % of ester units having a molar ratio of isophthalate to
terephthalate from 98:2 to 88:12 are often referred to as
poly(phthalate-carbonate)s (PPC). In these embodiments the PCE or
PPC (8) can be derived from the reaction of bisphenol-A and
phosgene with iso- and terephthaloyl chloride, and can have an
intrinsic viscosity of 0.5 to 0.65 deciliters per gram (measured in
methylene chloride at a temperature of 25.degree. C.).
[0032] In another specific embodiment, a poly(carbonate-ester)
comprises carbonate units (1) derived from a bisphenol compound
(3), and ester units derived from an aromatic dicarboxylic acid and
dihydroxy compound (6). Specifically, the ester units are arylate
ester units (9)
##STR00009##
wherein each R.sup.4 is independently a halogen or a C.sub.1-4
alkyl, and p is 0 to 3. The arylate ester units (9) can be derived
from the reaction of a mixture of terephthalic acid and isophthalic
acid or chemical equivalents thereof with compounds such as
5-methyl resorcinol, 5-ethyl resorcinol, 5-propyl resorcinol,
5-butyl resorcinol, 5-t-butyl resorcinol, 2,4,5-trifluoro
resorcinol, 2,4,6-trifluoro resorcinol, 4,5,6-trifluoro resorcinol,
2,4,5-tribromo resorcinol, 2,4,6-tribromo resorcinol,
4,5,6-tribromo resorcinol, catechol, hydroquinone, 2-methyl
hydroquinone, 2-ethyl hydroquinone, 2-propyl hydroquinone, 2-butyl
hydroquinone, 2-t-butyl hydroquinone, 2,3,5-trimethyl hydroquinone,
2,3,5-tri-t-butyl hydroquinone, 2,3,5-trifluoro hydroquinone,
2,3,5-tribromo hydroquinone, or a combination comprising at least
one of the foregoing compounds. The arylate ester units (8) can be
poly(isophthalate-terephthalate-resorcinol ester) units, also known
as "ITR" esters.
[0033] The poly(carbonate-ester)s comprising arylate ester units
(9) can comprise, based on the total weight of the copolymer, from
1 to less than 100 wt. %, 10 to less than 100 wt. %, 20 to less
than 100 wt. %, or 40 to less than 100 wt. % of carbonate units (1)
derived from a bisphenol compound (3), and from greater than 0 to
99 wt. %, greater than 0 to 90 wt. %, greater than 0 to 80 wt. %,
or greater than 0 to 60 wt. % of ester units derived from an
aromatic dicarboxylic acid and dihydroxy compound (6). A specific
poly(carbonate-ester) comprising arylate ester units (9) is a
poly(bisphenol-A
carbonate)-co-poly(isophthalate-terephthalate-resorcinol
ester).
[0034] In another specific embodiment, the poly(carbonate-ester)
contains carbonate units (1) derived from a combination of a
bisphenol (3) and an aromatic dihydric compound (6), and arylate
ester units (9). The molar ratio of carbonate units derived from
bisphenol (3) to carbonate units derived from aromatic dihydric
compound (6) can be 1:99 to 99:1. A specific poly(carbonate-ester)
of this type is a poly(bisphenol-A carbonate)-co-(resorcinol
carbonate)-co(isophthalate-terephthalate-resorcinol ester).
[0035] The polycarbonates can further comprise siloxane units, for
example a poly(carbonate-siloxane) or a
poly(carbonate-ester-siloxane). The siloxane units are present in
the copolymer in polysiloxane blocks, which comprise repeating
siloxane units (10)
##STR00010##
wherein each R is independently the same or different C.sub.1-13
monovalent organic group. For example, R can be a C.sub.1-C.sub.13
alkyl, C.sub.1-C.sub.13 alkoxy, C.sub.2-C.sub.13 alkenyl group,
C.sub.2-C.sub.13 alkenyloxy, C.sub.3-C.sub.6 cycloalkyl,
C.sub.3-C.sub.6 cycloalkoxy, C.sub.6-C.sub.14 aryl,
C.sub.6-C.sub.10 aryloxy, C.sub.7-C.sub.13 arylalkyl,
C.sub.7-C.sub.13 aralkoxy, C.sub.7-C.sub.13 alkylaryl, or
C.sub.7-C.sub.13 alkylaryloxy. The foregoing groups can be fully or
partially halogenated with fluorine, chlorine, bromine, or iodine,
or a combination thereof. In an embodiment, where a transparent
polysiloxane-polycarbonate is desired, R is unsubstituted by
halogen. Combinations of the foregoing R groups can be used in the
same copolymer.
[0036] The value of E in formula (10) can vary depending on the
type and relative amount of each component in the composition, the
desired properties of the, and like considerations. Generally, E
has an average value of 5 to 50, specifically 5 to about 40, more
specifically 10 to 30. A combination of a first and a second (or
more) copolymers can be used, wherein the average value of E of the
first copolymer is less than the average value of E of the second
copolymer.
[0037] In an embodiment, the polysiloxane blocks are of formula
(11) or (12)
##STR00011##
wherein E is as defined in siloxane (10) and each R can be the same
or different, and is as defined in siloxane (1). Each Ar in blocks
(11) and (12) can be the same or different, and is a substituted or
unsubstituted C.sub.6-C.sub.30 arylene group, wherein the bonds are
directly connected to an aromatic moiety. The Ar groups in (11) can
be derived from a bisphenol (3), for example
1,1-bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane,
2,2-bis(4-hydroxyphenyl) propane, 2,2-bis(4-hydroxyphenyl) butane,
2,2-bis(4-hydroxyphenyl) octane, 1,1-bis(4-hydroxyphenyl) propane,
1,1-bis(4-hydroxyphenyl) n-butane,
2,2-bis(4-hydroxy-1-methylphenyl) propane,
1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl sulfide),
and 1,1-bis(4-hydroxy-t-butylphenyl) propane. Combinations
comprising at least one of the foregoing compounds can also be
used. Each R.sup.5 in formula (12) is independently a divalent
C.sub.1-C.sub.30 organic group, for example a divalent
C.sub.2-C.sub.8 aliphatic group.
[0038] In a specific embodiment, the polysiloxane blocks are of
formula (13):
##STR00012##
wherein R and E are as defined in formula (10); R.sup.6 is a
divalent C.sub.2-C.sub.8 aliphatic group; each M is independently a
halogen, cyano, nitro, C.sub.1-C.sub.8 alkylthio, C.sub.1-C.sub.8
alkyl, C.sub.1-C.sub.8 alkoxy, C.sub.2-C.sub.8 alkenyl,
C.sub.2-C.sub.8 alkenyloxy group, C.sub.3-C.sub.8 cycloalkyl,
C.sub.3-C.sub.8 cycloalkoxy, C.sub.6-C.sub.10 aryl,
C.sub.6-C.sub.10 aryloxy, C.sub.7-C.sub.12 aralkyl,
C.sub.7-C.sub.12 aralkoxy, C.sub.7-C.sub.12 alkylaryl, or
C.sub.7-C.sub.12 alkylaryloxy, wherein each n is independently 0,
1, 2, 3, or 4. In an embodiment, M is bromo or chloro, an alkyl
group such as methyl, ethyl, or propyl, an alkoxy group such as
methoxy, ethoxy, or propoxy, or an aryl group such as phenyl,
chlorophenyl, or tolyl; R.sup.2 is a dimethylene, trimethylene or
tetramethylene group; and R is a C.sub.1-8 alkyl, haloalkyl such as
trifluoropropyl, cyanoalkyl, or C.sub.6-8 aryl such as phenyl,
chlorophenyl or tolyl. In another embodiment, R is methyl, or a
combination of methyl and trifluoropropyl, or a combination of
methyl and phenyl. In still another embodiment, M is methoxy, n is
one, R.sup.2 is a divalent C.sub.1-C.sub.3 aliphatic group, and R
is methyl.
[0039] In an embodiment, the polycarbonate is a
poly(carbonate-siloxane) which comprises carbonate units (1)
derived from a bisphenol (3), specifically bisphenol A, and
siloxane units (13) wherein M is methoxy, n is one, R.sup.2 is a
divalent C.sub.1-C.sub.3 aliphatic group, and R is methyl. The
poly(carbonate-siloxane)s can comprise 50 to 99 wt. % of carbonate
units and 1 to 50 wt. % siloxane units. Within this range, the
poly(carbonate-siloxane)s can comprise 70 to 98 wt. %, more
specifically 75 to 97 wt. % of carbonate units and 2 to 30 wt. %,
more specifically 3 to 25 wt. % siloxane units.
[0040] In another embodiment, the polycarbonate is a
poly(carbonate-ester-siloxane) which comprises carbonate units (1)
derived from a bisphenol (3), specifically bisphenol A; siloxane
units (13) wherein M is methoxy, n is one, R.sup.2 is a divalent
C.sub.1-C.sub.3 aliphatic group, and R is methyl and ester units
(9), specifically (isophthalate-terephthalate-resorcinol) ester
units.
[0041] Polycarbonates can be manufactured by processes such as
interfacial polymerization and melt polymerization. Although the
reaction conditions for interfacial polymerization can vary, an
exemplary process generally involves dissolving or dispersing a
dihydric phenol reactant in aqueous caustic soda or potash, adding
the resulting mixture to a water-immiscible solvent medium, and
contacting the reactants with a carbonate precursor in the presence
of a catalyst such as triethylamine and/or a phase transfer
catalyst, under controlled pH conditions, e.g., 8 to 12. The most
commonly used water immiscible solvents include methylene chloride,
1,2-dichloroethane, chlorobenzene, toluene, and the like.
[0042] Exemplary carbonate precursors include a carbonyl halide
such as carbonyl bromide or carbonyl chloride, or a haloformate
such as a bishaloformates of a dihydric phenol (e.g., the
bischloroformates of bisphenol A, hydroquinone, or the like) or a
glycol (e.g., the bishaloformate of ethylene glycol, neopentyl
glycol, polyethylene glycol, or the like). Combinations comprising
at least one of the foregoing types of carbonate precursors can
also be used. In an exemplary embodiment, an interfacial
polymerization reaction to form carbonate linkages uses phosgene as
a carbonate precursor, and is referred to as a phosgenation
reaction.
[0043] Among the phase transfer catalysts that can be used are
catalysts of the formula (R.sup.3).sub.4Q.sup.+X, wherein each
R.sup.3 is the same or different, and is a C.sub.1-10 alkyl group;
Q is a nitrogen or phosphorus atom; and X is a halogen atom or a
C.sub.1-8 alkoxy group or C.sub.6-18 aryloxy group. Exemplary phase
transfer catalysts include, for example,
[CH.sub.3(CH.sub.2).sub.3].sub.4NX,
[CH.sub.3(CH.sub.2).sub.3].sub.4PX,
[CH.sub.3(CH.sub.2).sub.5].sub.4NX,
[CH.sub.3(CH.sub.2).sub.6].sub.4NX,
[CH.sub.3(CH.sub.2).sub.4].sub.4NX,
CH.sub.3[CH.sub.3(CH.sub.2).sub.3].sub.3NX, and
CH.sub.3[CH.sub.3(CH.sub.2).sub.2].sub.3NX, wherein X is Cl.sup.-,
Br.sup.-, a C.sub.1-8 alkoxy group or a C.sub.6-18 aryloxy group.
An effective amount of a phase transfer catalyst can be 0.1 to 10
wt. % based on the weight of bisphenol in the phosgenation mixture.
In another embodiment an effective amount of phase transfer
catalyst can be 0.5 to 2 wt. % based on the weight of bisphenol in
the phosgenation mixture.
[0044] All types of polycarbonate end groups are contemplated as
being useful in the polycarbonate composition, provided that such
end groups do not significantly adversely affect desired properties
of the compositions.
[0045] Branched polycarbonate blocks can be prepared by adding a
branching agent during polymerization. These branching agents
include polyfunctional organic compounds containing at least three
functional groups selected from hydroxyl, carboxyl, carboxylic
anhydride, haloformyl, and mixtures of the foregoing functional
groups. Specific examples include trimellitic acid, trimellitic
anhydride, trimellitic trichloride, tris-p-hydroxy phenyl ethane,
isatin-bis-phenol, tris-phenol TC
(1,3,5-tris((p-hydroxyphenyl)isopropyl)benzene), tris-phenol PA
(4(4(1,1-bis(p-hydroxyphenyl)-ethyl)alpha, alpha-dimethyl
benzyl)phenol), 4-chloroformyl phthalic anhydride, trimesic acid,
and benzophenone tetracarboxylic acid. The branching agents can be
added at a level of 0.05 to 2.0 wt. %. Mixtures comprising linear
polycarbonates and branched polycarbonates can be used.
[0046] A chain stopper (also referred to as a capping agent) can be
included during polymerization. The chain stopper limits molecular
weight growth rate, and so controls molecular weight in the
polycarbonate. Exemplary chain stoppers include certain
mono-phenolic compounds, mono-carboxylic acid chlorides, and/or
mono-chloroformates. Mono-phenolic chain stoppers are exemplified
by monocyclic phenols such as phenol and C.sub.1-C.sub.22
alkyl-substituted phenols such as p-cumyl-phenol, resorcinol
monobenzoate, and p- and tertiary-butyl phenol; and monoethers of
diphenols, such as p-methoxyphenol. Alkyl-substituted phenols with
branched chain alkyl substituents having 8 to 9 carbon atom can be
specifically mentioned. Certain mono-phenolic UV absorbers can also
be used as a capping agent, for example
4-substituted-2-hydroxybenzophenones and their derivatives, aryl
salicylates, monoesters of diphenols such as resorcinol
monobenzoate, 2-(2-hydroxyaryl)-benzotriazoles and their
derivatives, 2-(2-hydroxyaryl)-1,3,5-triazines and their
derivatives, and the like.
[0047] Mono-carboxylic acid chlorides can also be used as chain
stoppers. These include monocyclic, mono-carboxylic acid chlorides
such as benzoyl chloride, C.sub.1-C.sub.22 alkyl-substituted
benzoyl chloride, toluoyl chloride, halogen-substituted benzoyl
chloride, bromobenzoyl chloride, cinnamoyl chloride,
4-nadimidobenzoyl chloride, and combinations thereof; polycyclic,
mono-carboxylic acid chlorides such as trimellitic anhydride
chloride, and naphthoyl chloride; and combinations of monocyclic
and polycyclic mono-carboxylic acid chlorides. Chlorides of
aliphatic monocarboxylic acids with less than or equal to 22 carbon
atoms are useful. Functionalized chlorides of aliphatic
monocarboxylic acids, such as acryloyl chloride and methacryoyl
chloride, are also useful. Also useful are mono-chloroformates
including monocyclic, mono-chloroformates, such as phenyl
chloroformate, alkyl-substituted phenyl chloroformate, p-cumyl
phenyl chloroformate, toluene chloroformate, and combinations
thereof.
[0048] Alternatively, melt processes can be used to make the
polycarbonates. Generally, in the melt polymerization process,
polycarbonates can be prepared by co-reacting, in a molten state,
the dihydroxy reactant(s) and a diaryl carbonate ester, such as
diphenyl carbonate, in the presence of a transesterification
catalyst in a Banbury.RTM. mixer, twin screw extruder, or the like
to form a uniform dispersion. Volatile monohydric phenol is removed
from the molten reactants by distillation and the polymer is
isolated as a molten residue. A specifically useful melt process
for making polycarbonates uses a diaryl carbonate ester having
electron-withdrawing substituents on the aryls. Examples of
specifically useful diaryl carbonate esters with electron
withdrawing substituents include bis(4-nitrophenyl)carbonate,
bis(2-chlorophenyl)carbonate, bis(4-chlorophenyl)carbonate,
bis(methyl salicyl)carbonate, bis(4-methylcarboxylphenyl)carbonate,
bis(2-acetylphenyl) carboxylate, bis(4-acetylphenyl) carboxylate,
or a combination comprising at least one of the foregoing esters.
In addition, useful transesterification catalysts can include phase
transfer catalysts of formula (R.sup.3).sub.4Q.sup.+X, wherein each
R.sup.3, Q, and X are as defined above. Exemplary
transesterification catalysts include tetrabutylammonium hydroxide,
methyltributylammonium hydroxide, tetrabutylammonium acetate,
tetrabutylphosphonium hydroxide, tetrabutylphosphonium acetate,
tetrabutylphosphonium phenolate, or a combination comprising at
least one of the foregoing.
[0049] The polyester-polycarbonates in particular can also be
prepared by interfacial polymerization as described above with
respect to polycarbonates generally. Rather than utilizing the
dicarboxylic acid or diol per se, the reactive derivatives of the
acid or diol, such as the corresponding acid halides, in particular
the acid dichlorides and the acid dibromides can be used. Thus, for
example instead of using isophthalic acid, terephthalic acid, or a
combination comprising at least one of the foregoing acids,
isophthaloyl dichloride, terephthaloyl dichloride, or a combination
comprising at least one of the foregoing dichlorides can be
used.
[0050] The polycarbonates can have an intrinsic viscosity, as
determined in chloroform at 25.degree. C., of 0.3 to 1.5 deciliters
per gram (dl/gm), specifically 0.45 to 1.0 dl/gm. The
polycarbonates can have a weight average molecular weight of 10,000
to 200,000 Daltons, specifically 20,000 to 100,000 Daltons, as
measured by gel permeation chromatography (GPC), using a
crosslinked styrene-divinylbenzene column and calibrated to
polycarbonate references. GPC samples are prepared at a
concentration of 1 mg per ml, and are eluted at a flow rate of 1.5
ml per minute. Combinations of polycarbonates of different flow
properties can be used to achieve the overall desired flow
property. In an embodiment polycarbonates are based on bisphenol A,
in which each of A.sup.3 and A.sup.4 is p-phenylene and Y.sup.2 is
isopropylidene. The weight average molecular weight of the
polycarbonate can be 5,000 to 100,000 Daltons, or, more
specifically 10,000 to 65,000 Daltons, or, even more specifically,
15,000 to 35,000 Daltons as determined by GPC as described
above.
[0051] The polyester-polycarbonates in particular are generally of
high molecular weight and have an intrinsic viscosity, as
determined in chloroform at 25.degree. C. of 0.3 to 1.5 dl/gm, and
preferably from 0.45 to 1.0 dl/gm. These polyester-polycarbonates
may be branched or unbranched and generally will have a weight
average molecular weight of from 10,000 to 200,000, preferably from
20,000 to 100,000 as measured by GPC as described above.
[0052] The poly(carbonate-siloxane)s can have a weight average
molecular weight of 2,000 to 100,000 Daltons, specifically 5,000 to
50,000 Daltons as measured by gel permeation chromatography using a
crosslinked styrene-divinyl benzene column, at a sample
concentration of 1 milligram per milliliter, and as calibrated with
polycarbonate standards. The poly(carbonate-siloxane)can have a
melt volume flow rate, measured at 300.degree. C./1.2 kg, of 1 to
50 cubic centimeters per 10 minutes (cc/10 min), specifically 2 to
30 cc/10 min. Mixtures of polyorganosiloxane-polycarbonates of
different flow properties can be used to achieve the overall
desired flow property.
[0053] The foregoing polycarbonates can be used alone or in
combination, for example a combination of a homopolycarbonate and
one or more poly(carbonate-ester)s, or a combination of two or more
poly(carbonate-ester)s. Blends of different polycarbonate-esters
may be used in these compositions.
[0054] In an embodiment, the polycarbonate film forming
compositions (and thus the films) contain less than 5 wt. % of
fluorine, specifically less than 4 wt. %, less than 3 wt. %, less
than 2 wt. %, less than 1 wt. %, each based on the total weight of
the composition.
[0055] In another embodiment, the polycarbonate film-forming
compositions and films contain less than 1000 ppm, specifically
less than 750 ppm, less than 500 ppm, or less than 50 ppm by weight
of a fluorine-containing compound. In a further embodiment, no
fluorine-containing compound is present in the film-forming
composition. Such compounds include, without limitation, certain
mold release agents, fillers (e.g., particulate PTFE), or flame
retardants.
[0056] In another embodiment, the polycarbonate film-forming
compositions (and thus the films) contain less than 1000 ppm,
specifically less than 750 ppm, less than 500 ppm, or less than 50
ppm by weight of a silicone compound. In an embodiment, no silicone
compound is present in the film-forming composition or film. Such
silicone compounds include, without limitation, silicone oils, and
polydimethyl siloxanes.
[0057] In an embodiment, the polycarbonate film-forming
compositions and films contain less than 1000 ppm, specifically
less than 750 ppm, less than 500 ppm, or less than 50 ppm by weight
of both a fluorine-containing compound and a silicone compound. In
an embodiment, no fluorine-containing compound and no silicone
compound is present in the film-forming compositions or films.
[0058] Good electrical properties are obtained when the
polycarbonate film-forming compositions and films contain low
levels of certain metal ions. Thus, the film-forming compositions
and films contain less than 50 ppm, specifically less than 40 ppm,
30 ppm, or 20 ppm by weight of each of aluminum, calcium,
magnesium, iron, nickel, potassium, manganese, molybdenum, sodium,
titanium, and zinc.
[0059] In some embodiments it is desired to use polycarbonate
film-forming compositions and films that are essentially free of
bromine and chlorine. "Essentially free" of bromine and chlorine
means that the composition has less than 3 wt. % of bromine and
chlorine, and in other embodiments, less than 1 wt. % bromine and
chlorine by weight of the film-forming composition. In other
embodiments, the composition is halogen free. "Halogen free" is
defined as having a halogen content (total amount of fluorine,
bromine, chlorine and iodine) of less than or equal to 1000 parts
by weight of halogen per million parts by weight of the total
composition (ppm). The amount of halogen can be determined by
ordinary chemical analysis such as atomic absorption.
[0060] The polycarbonate film-forming compositions can optionally
further comprise one or more particulate fillers to adjust the
properties thereof, for example dielectric constant, coefficient of
thermal expansion, and the like. Exemplary particulate fillers
include silica powder, such as fused silica and crystalline silica;
boron-nitride powder and boron-silicate powders; alumina, and
magnesium oxide (or magnesia); silicate spheres; flue dust;
cenospheres; aluminosilicate (armospheres); natural silica sand;
quartz; quartzite; titanium oxide, barium titanate, barium
strontium, tantalum pentoxide, tripoli; diatomaceous earth;
synthetic silica; and combinations thereof. All of the above
fillers can be surface treated with silanes to improve adhesion and
dispersion with the polymeric matrix resin. When present, the
amount of particulate filler in the polycarbonate film-forming
compositions can vary widely, and is that amount effective to
provide the desired physical properties. In some instances the
particulate filler is present in an amount from 0.1 to 50 vol. %,
0.1 to 40 vol. %, alternatively 5 to 30 vol. %, more particularly 5
to 20 vol. %, each based on the total weight of the film-forming
composition.
[0061] The polycarbonate film-forming compositions can include
various additives incorporated into dielectric substrate polymer
compositions with the proviso that the additives are selected so as
to not significantly adversely affect the desired properties of the
compositions. In an embodiment, any additives are present in an
amount that provides less than 1,000 ppm of a compound having a
molecular weight of less than 250 Daltons. Exemplary additives
include antioxidants, thermal stabilizers, light stabilizers,
ultraviolet light (UV) absorbing additives, quenchers,
plasticizers, lubricants, antistatic agents, flame retardants,
anti-drip agents, and radiation stabilizers. Combinations of
additives can be used. The foregoing additives (except any fillers)
are generally present individually in an amount from 0.005 to 20
wt. %, specifically 0.01 to 10 wt. %, based on the total weight of
the film-forming composition.
[0062] Suitable antioxidants can be compounds such as phosphites,
phosphonites and hindered phenols or mixtures thereof.
Phosphorus-containing stabilizers including triaryl phosphites and
aryl phosphonates are useful additives. Difunctional phosphorus
containing compounds can also be unseeded. Preferred stabilizers
can have a molecular weight greater than or equal to 300. Some
exemplary compounds are tris-di-tert-butylphenyl phosphite
available from Ciba Chemical Co. as IRGAPHOS 168 and
bis(2,4-dicumylphenyl) pentaerythritol diphosphite available
commercially from Dover Chemical Co. as DOVERPHOS S-9228.
[0063] Examples of phosphites and phosphonites include: triphenyl
phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites,
tris(nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl
phosphite, distearyl pentaerythritol diphosphite,
tris(2,4-di-tert-butylphenyl) phosphite, diisodecyl pentaerythritol
diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol
diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)-pentaerythritol
diphosphite, diisodecyloxy pentaerythritol diphosphite,
bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,
bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite,
tristearyl sorbitol tri-phosphite,
tetrakis(2,4-di-tert-butyl-phenyl) 4,4'-biphenylene diphosphonite,
bis(2,4-di-tert-butyl-6-methylphenyl)methyl phosphite,
bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite,
2,2',2''-nitrilo[triethyl
tris(3,3',5,5'-tetra-tert-butyl-1,1'-biphenyl-2,2'-diyl)phosphite],
2-ethylhexyl(3,3',5,5'-tetra-tert-butyl-1,1'-biphenyl-2,2'-diyl)phosphite
and
5-butyl-5-ethyl-2-(2,4,6-tri-tert-butylphenoxy)-1,3,2-dioxaphosphiran-
e.
[0064] Combinations comprising more than one organophosphorous
compound are contemplated. When used in combination the
organophosphorous compounds can be of the same type or different
types. For example, a combination can comprise two phosphites or a
combination can comprise a phosphite and a phosphonite. In some
embodiments, phosphorus-containing stabilizers with a molecular
weight greater than or equal to 300 are useful.
Phosphorus-containing stabilizers, for example an aryl phosphite
are usually present in the composition in an amount from 0.005 to 3
wt. %, specifically 0.01 to 1.0 wt. %, based on total weight of the
composition.
[0065] Hindered phenols can also be used as antioxidants, for
example alkylated monophenols, and alkylated bisphenols or poly
phenols. Exemplary alkylated monophenols include
2,6-di-tert-butyl-4-methylphenol; 2-tert-butyl-4,6-dimethylphenol;
2,6-di-tert-butyl-4-ethylphenol; 2,6-di-tert-butyl-4-n-butylphenol;
2,6-di-tert-butyl-4-isobutylphenol;
2,6-dicyclopentyl-4-methylphenol;
2-(alpha-methylcyclohexyl)-4,6-dimethylphenol;
2,6-dioctadecyl-4-methylphenol; 2,4,6-tricyclohexylphenol;
2,6-di-tert-butyl-4-methoxymethylphenol; nonyl phenols which are
linear or branched in the side chains, for example,
2,6-di-nonyl-4-methylphenol;
2,4-dimethyl-6-(1'-methylundec-1'-yl)phenol;
2,4-dimethyl-6-(1'-methylheptadec-1'-yl)phenol;
2,4-dimethyl-6-(1'-methyltridec-1'-yl)phenol and mixtures thereof.
Exemplary alkylidene bisphenols include
2,2'-methylenebis(6-tert-butyl-4-methylphenol),
2,2'-methylenebis(6-tert-butyl-4-ethylphenol),
2,2'-methylenebis[4-methyl-6-(alpha-methylcyclohexyl)-phenol],
2,2'-methylenebis(4-methyl-6-cyclohexylphenol),
2,2'-methylenebis(6-nonyl-4-methylphenol),
2,2'-methylenebis(4,6-di-tert-butylphenol),
2,2'-ethylidenebis(4,6-di-tert-butylphenol),
2,2'-ethylidenebis(6-tert-butyl-4-isobutylphenol),
2,2'-methylenebis[6-(alpha-methylbenzyl)-4-nonylphenol],
2,2'-methylenebis[6-(alpha, alpha-dimethylbenzyl)-4-nonylphenol],
4,4'-methylenebis-(2,6-di-tert-butylphenol),
4,4'-methylenebis(6-tert-butyl-2-methylphenol),
1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,
2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,
1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,
1,1-bis(5-tert-butyl-4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane-
, ethylene glycol
bis[3,3-bis(3'-tert-butyl-4'-hydroxyphenyl)butyrate],
bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene,
bis[2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-methylphe-
nyl]terephthalate, 1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane,
2,2-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propane,
2,2-bis-(5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobutane,
1,1,5,5-tetra-(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane and
mixtures thereof.
[0066] The hindered phenol compound can have a molecular weight of
greater than or equal to 300 g/mole. The high molecular weight can
help retain the hindered phenol moiety in the polymer melt at high
processing temperatures, for example greater than or equal to
300.degree. C. Hindered phenol stabilizers, are usually present in
the composition in an amount from 0.005 to 2 wt. %, specifically
0.01 to 1.0 wt. %, based on total weight of the composition.
[0067] In some embodiments, the polycarbonate film-forming
compositions can further optionally include at least one additional
amorphous polymer, again with the proviso that the polymers are
selected so as to not provide more than 5 wt. % of fluorine or
silicon, or otherwise not significantly adversely affect the
desired properties of the compositions. Examples of such additional
polymers include and are not limited to poly(phenylene sulfone)s,
poly(sulfone)s, poly(ether sulfone)s, poly(arylene sulfone),
poly(phenylene ether)s, poly(etherimide)s, and poly(etherimide
sulfone)s as well as blends and co-polymers thereof. When present,
the polymer is used in an amount from more than 0 to 12 wt. %,
specifically 0.1 to 10 wt. %, more specifically from 0.5 to 5 wt.
%, all based on the total weight of the composition. In an
embodiment, no polymer other than the polycarbonate is present in
the film-forming composition.
[0068] The polycarbonate film-forming compositions can be prepared
by blending the ingredients under conditions for the formation of
an intimate blend. Such conditions often include melt mixing in
single or twin screw type extruders, mixing bowl, or similar mixing
devices that can apply a shear to the components. Twin-screw
extruders are often preferred due to their more intensive mixing
capability and self-wiping capability, over single screw extruders.
It is often advantageous to apply a vacuum to the blend through at
least one vent port in the extruder to remove volatile impurities
in the composition. Often it is advantageous to dry the
polycarbonate (and/or other additives) prior to melting. The melt
processing is often done at 240.degree. C. to 360.degree. C. to
avoid excessive polymer degradation while still allowing sufficient
melting to get an intimate polymer mixture free of any unmelted
components. The polymer blend can also be melt filtered using a 40
to 100 micrometer candle or screen filter to remove undesirable
black specks or other heterogeneous contaminants, for example any
particles having a diameter of greater than 1 micrometer.
[0069] In an exemplary process, the various components are placed
into an extrusion compounder to produce a continuous strand that is
cooled and then chopped into pellets. In another procedure, the
components are mixed by dry blending, and then fluxed on a mill and
comminuted, or extruded and chopped. The composition and any
optional components can also be mixed and directly extruded to form
a film. In an embodiment, all of the components are freed from as
much water as possible. In addition, compounding is carried out to
ensure that the residence time in the machine is short; the
temperature is carefully controlled; the friction heat is utilized;
and an intimate blend between the components is obtained.
[0070] The composition can be extruded using extruders
conventionally used for thermoplastic compositions using a flat
die. The extrusion cast film method involves the melting of the
polymer in an extruder, conveying of the molten polymer through a
flat die of small lip gap separation, the stretching of the film at
relatively high take-up speeds, and the cooling/solidification of
the polymer to form the final film. The extruder may be of the
single- or twin-screw design, and a melt pump may also be used to
provide a constant, non-pulsating flow of polymer through the die.
The die lip gap may be as small as 100 to 200 micron, and the
take-up rollers may operate at speeds of up to 200 m/min. The
design may also include the addition of a heated roll to
temper/anneal the film and thus minimize the occurrence of
frozen-in internal stresses. The edges of the film are often
trimmed, and the film wound up on a roll using a tension-controlled
winding mechanism. In some instances, commercial and/or
experimentally functionalized fillers can be uniformly dispersed in
the polymer prior to stretching the composite material into a thin
film. In these cases, the compounding of the filler into the
polymeric matrix to obtain a uniform dispersion can be done on a
separate extruder or alternatively, and more preferably, on the
same extruder used to effect the melting of the polymer prior to
the stretching operation. The accuracy of delivering a constant and
uniform flow of molten polymer through the die, the rheological
properties of the polymer used to make the film, the cleanliness of
both resin and equipment, and the mechanical characteristics of the
take-up mechanism will all contribute to the successful preparation
of these extruded films having relatively small thicknesses.
[0071] In an embodiment, the extrusion cast film method is
one-step, scalable to larger size equipment, and does not require
the use of any solvent. Even for the case of polymers of high
molecular weight and/or high glass transition temperature; this
extrusion process can be properly designed to provide an
environment for the polymer that does not lead to excessive
temperatures that can cause the thermal or mechanical degradation
of the material. The use of a filtration device for the melt
produces a film that is virtually free of contaminants, such as
gels and black specks, which would damage the dielectric
performance of these films if not properly removed from the melt.
The films produced by this method are thin (10 micron in thickness,
and even thinner), of uniform thickness across the web, flat with
almost no wrinkles or surface waviness, and relatively free of
contamination.
[0072] The melted composition can be conveyed through the extruder
die using a melt pump. In an embodiment, the film is extruded at
temperatures from 250.degree. C. to 500.degree. C., for example
300.degree. C. to 450.degree. C., and the extruded film is
uniaxially stretched to produce the dielectric substrate film.
Specifically, the components of the film-forming composition are
combined, melted, and intimately mixed, then filtered to remove
particles greater than 1 micrometer; extruded through a flat die at
the foregoing temperatures; and then uniaxially stretched. After
stretching, the film can be directly metallized as described below,
or wound on a take-up roll for storage or shipping. The film can
have a length of at least 10, or 100 to 10,000 meter, and a width
of at least 300, or 300 to 3,000 millimeter. The rate which the
film can be extruded can vary. In commercial embodiments, the rate
at which the film can be extruded varies from 10 lb/hr (4.5 kg/hr)
to 1000 lb/hr (450 kg/hr). The rate at which the film can be pulled
from the die plate of the extruder (the take-up speed) can range
from 10 meter/minute to 300 meter/minute.
[0073] The films can be metallized on at least one side thereof. A
variety of metals can be used depending on the intended use of the
film, for example copper, aluminum, silver, gold, nickel, zinc,
titanium, chromium, vanadium, and others. The films are metallized
at least on the smooth side, that is, the side having an average
surface roughness Ra of less than +/-3% of the average film
thickness as determined by optical profilometry. Methods for the
metallization of polymer films are known, and include, for example,
vacuum metal vapor deposition, metal sputtering, plasma treatments,
electron beam treatments, chemical oxidation or reduction
reactions, as well as electroless wet-chemical deposition. The
films can be metallized on both sides by conventional electroless
plating. In another embodiment, a patterned metal layer can be
formed on a surface of the film, for example by ink jet printing.
The thickness of the metallized layer is determined by the intended
use of the metallized film, and can be, for example, 1 Angstrom to
1000 nanometers, 500 nanometer, or 10 nanometer. In an embodiment,
the thickness of the metal film can be 1 to 3000 Angstrom, 1 to
2000 Angstrom, or 1 to 1000 Angstrom. If a conductive metal is
used, the resistivity of the metal layer on the polymer film can
vary from 0.1 to 1000 Ohm per square or 0.1 to 100 Ohm per
square.
[0074] The surface of the film to be metallized can be pre-treated,
for example by washing, flame treatment, plasma discharge corona
discharge, or the like, for example to enhance adhesion of the
metal layer. One or more additional layers can be deposited on the
metal layer, for example a clear coat (such as a poly(methyl
methacrylate) or poly(ethyl methacrylate) to provide scratch
resistance), or another layer of the polycarbonate film to form a
laminate.
[0075] The films and metallized films thus produced have a variety
of advantageous physical properties. The films have at least one
region that is wrinkle-free, that is, sufficiently flat and smooth
so that when a surface thereof is metallized, the metallized film
has an advantageously consistent surface morphology. In an
embodiment, the breakdown strength of the un-metallized film is at
least 300 Volt/micrometer, alternatively at least 350
Volt/micrometer, alternatively at least 400 Volt/micrometer. In an
embodiment, the breakdown strength of the unmetallized film can be
up to 520, 550, 580, 610, 640, 670, and 700 Volt/micrometer.
[0076] The flatness of the wrinkle-free regions of the films can be
determined by measuring the variation in thickness of the film over
a specific area. Here, flat films have variation of the thickness
of the film of plus or minus (+/-) 10% or less, alternatively +/-9%
or less, +/-8% or less, +/-6% or less, or +/-5%, +/-4%, +/-3%,
+/-2%, +/-1% or less, based on the average thickness of the film
over the measured area. In an embodiment, the variation in
thickness can be as low as +/-1%.
[0077] The smoothness of the wrinkle-free regions of a surface of
the films can be quantitated by measuring the surface roughness
average ("Ra") of the surface by optical profilometery. Here, the
wrinkle-free regions of the films have a surface having an Ra of
less than +/-3%, less than /-2%, or a low as +/-1% of the average
thickness of the film as measured by optical profilometery.
[0078] In a particularly advantageous feature, the wrinkle-free
regions can be produced over a large area of the film. For example,
at least 80%, at least 85%, at least 90%, at least 95%, or at least
97% of area of the film can be wrinkle-free. As such, the films can
have wrinkle-free regions having a lower limit and/or an upper
limit. The range can include or exclude the lower limit and/or the
upper limit. The lower limit and/or upper limit can be selected
from 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94,
95, 96, 97, 98, 99, and 100% of the area of the film. In another
embodiment, the wrinkle-free region can have a contiguous area of
at least 1 square meter (m.sup.2), at least 2 m.sup.2, at least 3
m.sup.2, at least 5 m.sup.2, at least 10 m.sup.2, at least 20
m.sup.2, at least 50 m.sup.2, or at least 100 m.sup.2. The large
size of the wrinkle-free regions offers a significant manufacturing
advantage, in that the metallized films can be manufactured,
stored, and shipped in roll form. Thus, the film can have a length
of at least 10 meter, and a width of at least 300 millimeter,
wherein at least 80%, at least 85%, at least 90%, at least 95%, or
at least 97% of area of the film is the wrinkle-free region. In
another embodiment, the film has a length of 100 to 10,000 meter,
and a width of 300 to 3,000 millimeter, wherein at least 80%, at
least 85%, at least 90%, at least 95%, or at least 97% of area of
the film is the wrinkle-free region. As such, when the films have a
length ranging from 100 to 10,000 meters, the films can have
wrinkle-free regions having a lower limit and/or an upper limit.
The range can include or exclude the lower limit and/or the upper
limit. The lower limit and/or upper limit can be selected from 80,
81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,
98, 99, and 100% of the area of the film.
[0079] The composition and manufacturing method can be varied to
achieve the desired performance properties, in particular
electrical properties.
[0080] The films can have a high dielectric constant, in particular
greater than 2.7, greater than 3.0, or greater than 3.2, 3.3, 3.4,
4.2, 4.3, 4.4, or 4.5, up to 7.0.
[0081] The films further can have a dielectric constant that is
stable up to the Tg of the polymer that they are made from.
Generally, the films are used in environment at a temperature that
is lower than the film's polymer's respective Tg, e.g.
approximately 20.degree. C. lower. In one embodiment, films further
can have a dielectric constant that is stable up to 50.degree. C.,
up to 60.degree. C., up to 70.degree. C., up to 80.degree. C., up
to 90.degree. C., up to 100.degree. C., up to 110.degree. C., up to
120.degree. C. or higher.
[0082] The films and the metallized films can be essentially
solvent-free, that is, contain less than 1,000 ppm, less than 750
ppm, less than 500 ppm, or less than 250 ppm of a compound having a
molecular weight of less than 250 Daltons.
[0083] The films and the metallized films can have less than 50
ppm, less than 25 ppm, or less than 10 ppm each of aluminum,
calcium, magnesium, iron, nickel, potassium, manganese, molybdenum,
sodium, titanium, and zinc in the polycarbonate layer.
[0084] The films and the metallized films can have less than 1000
ppm, less than 500 ppm, less than 250 ppm, or less than 100 ppm
each of a fluorine-containing compound or a silicone-containing
compound.
[0085] The films and the metallized films can have no observable
specks or gels over an area of at least 3 square meters, or over an
area of at least 9 square meters when viewed at a distance of 0.3
meter without magnification.
[0086] The films and the metallized films can have no observable
voids over an area of at least 3 square meters, or over an area of
at least 9 square meters when viewed at a magnification of
50.times..
[0087] The metallized films can have a dissipation factor, as
measured by dielectric spectroscopy, ranging from more than 0 and
less than 5%, alternatively more than 0 and less than 4%,
alternatively more than 0 and less than 3%, alternatively more than
0 and less than 2%, alternatively more than 0 and less than 1%. In
one embodiment, the films have a low dissipation factor, that is,
less than 0.1%, or less than 0.08%.
[0088] The polycarbonate films can be used in any amorphous film
application, but are particularly suitable for metallization. The
metallized films can be used in any metallized film application,
but are particularly suitable for electrical applications, for
example as capacitors or circuit materials. High energy density,
high voltage non-polar capacitors can be made using a metalized
polymer film that is wound into a cylindrical shape. In a specific
embodiment, the polycarbonate film is extruded, then metallized by
spraying a conductive metal such as copper or aluminum onto the
moving polymer film via vapor deposition in a vacuum chamber, to a
thickness from 1 Angstrom to 1000 nanometers, 1 to 3000 Angstrom,
or 1 to 1000 Angstrom. The resistivity of the metal on the polymer
film can be in a range from about 0.1 Ohm per square to 100 Ohm per
square. Before the metallization process is performed, the polymer
film can be appropriately masked to provide unmetallized margins at
the edges of the width of the film, so that alternate layers of
metallized film (when the capacitor is assembled) have unmetallized
regions at opposite edges to prevent electrical shorting of the
electrodes of the capacitor when the end metallization is
ultimately applied.
[0089] The capacitors can then be fabricated by rolling two stacked
metalized polymer films into a tubular shape. Electrical wires are
connected to each metal layer. In a specific embodiment, two
separate rolls of the metallized film are placed in a capacitor
winder and wound tightly together on a mandrel (which may
subsequently be removed) so that the layers are arranged in the
sequence polycarbonate/metallized layer/polycarbonate/metallized
layer, to replicate a typical construction of a capacitor, i.e., a
dielectric with two metallic layers on opposite sides. The two
rolls of film are wound with the unmetallized margins on opposite
sides.
[0090] The extent of winding of the capacitor depends on the
physical size of the capacitor desired or on the capacitance
desired. Tight winding of the two rolls aids in removing any
entrapped air that might otherwise cause premature breakdown.
Individual capacitors can be processed in a clean room environment
of at least class 100, incorporating HEPA filters, to reduce the
likelihood of contamination of the contact point between the
dielectric film layers by foreign particles, as well as reducing
moisture intake in the dielectric. Electric winding can be used to
better maintain uniform tension on each capacitor. The capacitor
can then be taped at the edges thereof and strapped in a tray open
on both sides, to prevent unwinding of the film layers and to allow
the edges or ends of the cylinder to be sprayed with a conductive
element, for example with a high zinc content solder followed by a
regular softer end spray solder of 90% tin, 10% zinc. The first
spray scratches the metallized surface and creates a trough to
achieve better contact with the metallization on the dielectric
film. The combination of end sprays further aids better contact
adhesion with the final termination. Subsequently, conductive,
e.g., aluminum leads can then be soldered onto each end to form the
final termination. One termination can be spot welded to the bottom
of the can, while the other termination can be parallel welded to
the lid. The capacitor may be filled with a liquid impregnate (for
example, isopropyl phenyl sulfone), in vacuum filling apparatus,
and closed.
[0091] Other capacitor configurations are possible. For example,
the capacitor can have a flat configuration comprising at least a
first and a second electrode disposed in a stacked configuration;
and the polycarbonate film disposed between and in at least partial
contact with each of the first and second electrodes. Additional
polycarbonate films and electrode layers can be present in
alternating layers. Thus, a multilayer article for forming an
electronic device is within the scope of the present claims,
comprising a polycarbonate layer/metal layer/dielectric layer,
wherein the dielectric layer can be a polycarbonate film as
describe herein, or other dielectric material. Additional layers
(e.g., additional alternating dielectric/metal layers) can
optionally be present.
[0092] The following Examples are illustrative, and
non-limiting.
EXAMPLES
Materials
[0093] The Examples were performed according to the procedures
below using the materials identified in Table 1.
Testing Procedures
[0094] Film thickness is measured using a Filmetrics F20 Thin Film
Measurement System, manufactured by Filmetrics Inc., San Diego,
Calif., which employs spectral reflectance to measure a film's
thickness by reflecting light off the film and analyzing the
reflected light over a range of wavelengths.
[0095] Surface roughness is determined using an optical
profilometer manufactured by Wyko NT100, operated in the unit's
standard operating mode. Measured values are reported under
conventional headings such as Ra, Sq, etc., in which "R" indicates
that the value was calculated using 2D data and represents linear
or profile roughness and "S" indicates that the value was
calculated using 3D data and represents surface or area roughness.
The second character indicates the formula type used in the
calculation, where for example "a" indicates an arithmetic formula
and "q" indicates a root mean square formula.
[0096] Metal contamination was determined by ICP (Inductively
Coupled Plasma Spectroscopy, which is a known method for measuring
metal contamination).
[0097] Dielectric Constant (DK) and Dissipation Factor (DF) were
determined using dielectric spectroscopy. Polymer films with very
uniform film thickness are used as the test samples. The film
thickness d is precisely determined by micrometers or optical
thickness gauges (if the film is transparent). Gold or aluminum
electrodes with known area A are deposited on both sides of the
film sample using sputtering or thermal evaporation. The metallized
sample is then loaded into a temperature-controlled chamber and
electrically connected with a dielectric spectrum analyzer, such as
the Novocontrol Broadband Dielectric Spectrometers. The spectrum
analyzer measures the capacitance C and the dissipation factor DF.
The DK of the sample is calculated based on the measured
capacitance and the area and thickness of the sample:
DK = Cd A 0 , ##EQU00001##
where .di-elect cons..sub.0=8.85.times.10.sup.-12 F/m, the vacuum
permittivity constant.
[0098] Dielectric breakdown was determined in accordance with ASTM
D-149. A piece of polymer film with uniform thickness is used as
the test sample and the thickness is measured using the same method
as for the DK and DF measurement. The film sample is tested as a
bare film without electrodes deposited on its surface. The film
sample is placed between two metal electrodes, where the bottom
electrode is a flat copper plate and the top electrode is a
stainless steel ball with 1/4 inch diameter. During the breakdown
measurement, a continuously increasing DC voltage is applied on the
sample between the two electrodes, starting from 0 V and increasing
with a fixed rate of 500 V/sec. The DC voltage is applied using a
high voltage power supply, such as the Hipotronics DC Power Supply.
The voltage increases until dielectric breakdown occurs, which
generates large current and causes the power supply to
automatically reset through its protection circuits. The highest
reached voltage is recorded as the breakdown voltage V.sub.BD, and
the breakdown electric field E.sub.BD is determined by dividing
V.sub.BD by the film thickness d. This method was employed unless
another method is identified.
[0099] Insulation resistance is measured by a megohm meter with a
time tested function, temperature meter, and similar features.
[0100] Compression Molding Procedure--Approximately 1.5 grams of
powder or pellets were weighed into a 20 ml vial and covered with a
Kim wipe and rubber band. This was dried in a vacuum oven overnight
at 80.degree. C. The next day the vacuum was removed and nitrogen
if used to fill the vacuum oven. Samples were removed quickly and
the vial was capped. The resulting dry, capped samples were held
for at least 4-8 hours. A 4.times.5 inch (101 mm.times.127 mm)
ferro-plate was placed on a larger steel plate. Three shims that
are 2 inches (101 mm) long and of the desired sample thickness were
placed on the ferro-plate in such a manner to form 3 sides of a
square. When ready to mold, individual samples were quickly poured
into the center, and another ferro-plate and steel plate was placed
on top. This entire stack was placed into an automated press such
as a Tetrahedron press. The initial temperature setting was
512.degree. F. (270.degree. C.) and the platen was raised just
enough to lift the upper platen, but not enough to engage the
hydraulics. After 3 minutes of equilibration, the platen was raised
to engage the automated press and the pressure rapidly rose to
15,000 lbs (6,804 kg) and was held there for 5 minutes at this
temperature and pressure. The press then automatically cooled to
212.degree. F. (100.degree. C.) while maintaining the 15,000 lbs
(6,804 kg) of pressure and held at the final temperature for 5
minutes. Once the press released at the end, the sample was quickly
removed and the plates were pulled away from the sample while still
warm. If a sample remained stuck to the plates, they were soaked in
water for a period of time to allow easy release.
[0101] This procedure was used for materials with Tg's of
approximately 180.degree. C. For polycarbonates that have Tg's in
the 145.degree. C.-150.degree. C. range, the initial and final
temperatures of the press were each reduced by 20.degree. C. It was
observed that hazy films were produced if the final temperatures
were in the 200.degree. C.-220.degree. C., apparently from
crystallization in the melt. Film thicknesses typically ranged from
225-275 .mu.m depending on the Tg of material. If low bulk density
powders produced bubbles following this procedure, the samples were
cold pressed first. The 1.5 grams of powder was placed in a 1 inch
(25.4 mm) diameter mold and Carver pressed to form a coin-like
disk. This could then be dried overnight in the same manner and
used to make films. Finally, film thicknesses could be adjusted by
using different thickness shims
TABLE-US-00001 TABLE 1 Material Trade Name Source Polycarbonate 1
(PC1) Lexan 135 Resin SABIC Innovative Plastics Polycarbonate 2
(PC2) APEC Bayer PMR-00039808 Resin Polycarbonate 3 (PC3) Lexan XHT
4141 SABIC Innovative Plastics Resin Polycarbonate 4 (PC4) Lexan
151 Resin SABIC Innovative Plastics Polycarbonate 5 (PC5) Lexan
ML5221 SABIC Innovative Plastics Resin Polyetherimide (PEI) Ultem
1000 Resin SABIC Innovative Plastics Copolyestercarbonate 1 Lexan
Resin SABIC Innovative Plastics (CPC1) Copolyestercarbonate 2 Lexan
Resin SABIC Innovative Plastics (CPC2) Copolyestercarbonate 3 Lexan
Resin SABIC Innovative Plastics (CPC3) Copolyestercarbonate 4 Lexan
Resin SABIC Innovative Plastics (CPC4) Copolyestercarbonate 5 Lexan
Resin SABIC Innovative Plastics (CPC5) Copolyestercarbonate 6 Lexan
Resin SABIC Innovative Plastics (CPC6)
Comparative Example 1
[0102] Two polycarbonate resins of different glass transition
temperatures, PC1 (a bisphenol A-based polycarbonate) and PC2, were
extruded into thin films, and their dielectric breakdown strengths
evaluated. The results are presented in Table 2.
TABLE-US-00002 TABLE 2 Comp. Ex. 1A Comp. Ex. 1B Comp. Ex. 1C Comp.
Ex. 1D Die size (in/mm) 3/76.2 3/76.2 3/76.2 3/76.2 Die gap
(in/micron) 0.005/125 0.005/125 0.005/125 0.005/125 Screw design
Standard, Low Standard, Low Standard, Low Standard, Low Mixing
mixing mixing mixing Material PC1 PC1 PC2 PC2 Melt Temperature
(.degree. C.) 311 Extruder Barrel Temperature Set Actual Set Actual
Set Actual Set Actual Die head T (.degree. C.) 320 316 340 340 Die
adaptor T (.degree. C.) 320 316 340 340 Adaptor T (.degree. C.) 320
320 340 340 Extruder Front T (.degree. C.) 310 310 340 340 Extruder
Middle T (.degree. C.) 300 301 340 340 Extruder Middle T (.degree.
C.) 280 280 340 340 Extruder Back T (.degree. C.) 260 259 320 320
Screw speed (rpm) 200 200 200 Torque (%/Nm) 43/11.2 35/9.4 30/8.6
30/8.6 Die pressure (psi)/(MPa) 745/5.13 560/3.86 600/4.13 420/2.89
Throughput (set) (lb/hr)/(kg/hr) 0.5/0.227 0.25/0.114 0.5/0.227
0.25/0.114 Throughput (actual) 0.4822/0.219 0.2441/0.111
0.4822/0.219 0.2441/0.111 (lb/hr)/(kg/hr) Roll speed actual
11.4/3.47 11.4/3.47 11.4/3.47 11.4/3.47 (ft/min)/(m/min) Forced air
to cool film @ die Yes Yes Yes Yes exit Film thickness (micron)
8.9/0.5/20 4.9/0.6/20 10.3/1.4/20 5.4/0.7/20 Mean St dev/#samples
Breakdown strength (V/micron) 804/99/20 818/93/20 838/121/20
787/151/20 Mean/St dev/#samples
[0103] Discussion: Table 2 shows that films of PC1 (Tg=152.degree.
C.) and PC2 (Tg=204.degree. C.) of less than 7 micron in thickness
and dielectric breakdown strengths higher than about 750 V/micron
can be made by melt extrusion. These films were made at polymer
rates equal to 0.25 lb/hr, and take-up speed equal to 11.4 ft/min.
Since these films showed wrinkles, die lines and other
imperfections, they did not have the level of quality that is
required for the manufacture of electrostatic film capacitors.
Comparative Example 2
[0104] Table 3 shows the film thicknesses and dielectric breakdown
strengths of films made by extrusion from PC3 having a glass
transition temperature equal to 181.5.degree. C.
TABLE-US-00003 TABLE 3 Comp. Ex. 2A Comp. Ex. 2B Comp. Ex. 2C Comp.
Ex. 2D Comp. Ex. 2E Material PC3 PC3 PC3 PC3 PC3 Die size (in)/(mm)
3/76.2 3/76.2 3/76.2 3/76.2 3/76.2 Die gap (in/micron) 0.005/125
0.005/125 0.005/125 0.005/125 0.005/125 Screw design Standard,
Standard, Low Standard, Low Standard, Low Standard, Low Low mixing
mixing mixing mixing mixing Melt Temperature (.degree. C.) ~315
Extruder Barrel Temperature Set Actual Set Actual Set Actual Set
Actual Set Actual Die head T (.degree. C.) 320 315 320 330 Die
adapter T (.degree. C.) 320 320 330 Adapter T (.degree. C.) 320 320
320 Extruder Front T (.degree. C.) 320 320 320 Extruder Middle T
(.degree. C.) 320 320 320 Extruder Middle T (.degree. C.) 300 300
300 Extruder Back T (.degree. C.) 280 280 280 Screw speed (rpm) 250
250 250 250 250 Torque (%/Nm) 37/10.4 37/10.2 30/8.2 25/7.8 Die
pressure ~820/5.65 810/5.58 750/5.17 675/4.65 500/3.45 (psi)/(MPa)
Throughput (set) 0.5/0.227 0.5/0.227 0.5/0.227 0.4/0.182 0.4/0.182
(lb/hr)/(kg/hr) Roll speed actual 7.6/2.32 11.4/3.47 15.2/4.63
15.2/4.63 17.1/5.21 (ft/min)/(m/min) Film width (in)/(mm) About
About 2.5/63.5 2.5/63.5 Forced air to cool film Yes/8 psi Yes Yes
Yes Yes @ die exit Film thickness (micron) 13.7/1.2/20 10.7/1.6/20
7.5/1.3/20 6.0/1.1/20 4.4/0.8/20 Mean/St dev/#samples Breakdown
strength 698/93/20 710/119/20 629/131/20 713/136/20 706/121/20
(V/micron) Mean/St dev/#samples
[0105] Discussion: Although these films had a relatively high
breakdown strength, the presence of wrinkles, die lines and other
imperfections made them unsuitable for the manufacture of
electrostatic film capacitors.
Example 1
[0106] Table 4 shows the thickness distribution across the web of a
film of PC4 about 6 micrometers thick, about 45 in wide and about
6,000 ft long.
TABLE-US-00004 TABLE 4 Distance from left Film Thickness edge
Measurement # (.mu.m) (in)/(mm) 1 7.4171 2/51 2 6.1876 4/102 3
6.5986 6/152 4 5.6736 8/203 5 6.3265 10/254 6 6.0949 12/305 7
6.0564 14/355 8 6.0961 16/406 9 5.4231 18/457 10 6.3784 20/508 11
5.4621 22/558 12 6.1343 24/610 13 5.2897 26/660 14 6.6928 28/711 15
6.0192 30/762 16 5.7591 32/813 17 5.6524 34/864 18 5.8041 36/914 19
5.4151 38/965 20 5.8695 40/1016 21 5.2719 42/1067 22 5.935 44/1118
AVERAGE 5.98 ST DEV 0.51 % Error 9
[0107] These results showed that 22 measurements of the film
thickness across the web gathered around the mean value of 5.98
micron with one standard deviation of only 0.51 micron.
[0108] Table 5 shows the dielectric breakdown strength of the film
of PC4 for which thickness measurements were recorded on Table
4.
TABLE-US-00005 TABLE 5 Breakdown Breakdown Thickness Voltage
Strength Site (micron) (kVDC) (C/micron) 1 5.56 3.79 682 2 5.56
3.79 682 3 5.61 3.74 667 4 5.60 4.34 775 5 5.71 4.37 765 6 5.72
4.13 722 7 5.83 4.35 746 8 5.91 4.39 743 9 5.90 3.81 646 10 5.95
4.39 738 11 5.99 3.22 538 12 6.03 4.39 728 13 6.05 4.54 750 14 6.08
4.86 799 15 6.22 4.64 746 16 6.24 3.93 630 17 6.30 4.45 706 18 6.33
4.38 692 19 6.35 4.87 767 20 6.35 4.40 693 Mean 6.0 4.24 711 StDev
0.28 0.41 60
[0109] Discussion: These results showed that the film of PC4 had a
breakdown strength in excess of 700 V/micron with a standard
deviation of only 60 V/micron and failed at an average voltage of
about 4,240 VDC.
[0110] Table 6 shows the surface roughness (Ra) of the two sides of
the same film of PC4 as measured by Optical Profilometry.
TABLE-US-00006 TABLE 6 Sample Ra (um) Rq (um) Side 1 0.0126 0.0161
0.0142 0.0185 0.0132 0.0169 0.0187 0.0238 0.0182 0.0229 0.0154
0.0191 average 0.0154 0.0196 stdev 0.0026 0.0031 Side 2 0.0109
0.0140 0.0108 0.0149 0.0097 0.0125 0.0104 0.0138 0.0100 0.0127
0.0133 0.0171 average 0.0108 0.0142 stdev 0.0013 0.0017
[0111] These results showed that the average roughness values were
about 15 and 11 nm for both sides, which were below the 180 nm
allowed by the specification for the manufacture of electrostatic
metallized film capacitors (less than about 3% of the average film
thickness).
[0112] Elemental analysis by Inductively Coupled Plasma Mass
Spectroscopy was performed on several films of polycarbonate and
polyetherimide made by the extrusion method. Table 7 below shows
that the amounts of metals found in these films were within the
acceptable ranges allowed by the specification for the manufacture
of metallized film capacitors.
TABLE-US-00007 TABLE 7 ICP - Results in .mu.g/g (ppm). Al, .mu.g/g
Ca, .mu.g/g Mg, .mu.g/g Ni, .mu.g/g Na, .mu.g/g Fe, .mu.g/g Sample
Name .+-.95% CI .+-.95% CI .+-.95% CI .+-.95% CI .+-.95% CI .+-.95%
CI PC5 5.7 .+-. 0.2 57 .+-. 0.3 2.1 .+-. 0.1 11.3 .+-. 0.5 2.4 .+-.
0.1 28.0 .+-. 0.5 2.3 .+-. 0.1 204 .+-. 0.5 1.2 .+-. 0.1 10.5 .+-.
0.4 3.8 .+-. 0.1 22.9 .+-. 0.3 2.5 .+-. 0.1 198 .+-. 0.5 0.9 .+-.
0.1 9.3 .+-. 0.4 6.1 .+-. 0.1 33.8 .+-. 0.3 PEI8.5 2.9 .+-. 0.2 81
.+-. 0.3 1.0 .+-. 0.1 35.1 .+-. 0.5 10.3 .+-. 0.1 108 .+-. 0.6 2.9
.+-. 0.1 88 .+-. 0.3 0.8 .+-. 0.1 31.8 .+-. 0.5 12.0 .+-. 0.1 136
.+-. 0.7 PEI7.2 3.7 .+-. 0.2 57 .+-. 0.3 1.2 .+-. 0.1 29.2 .+-. 0.6
13.7 .+-. 0.1 142 .+-. 0.8 3.6 .+-. 0.2 47 .+-. 0.3 1.0 .+-. 0.1
36.1 .+-. 0.6 12.6 .+-. 0.1 141 .+-. 0.8 PC4 3.1 .+-. 0.1 33 .+-.
0.2 1.0 .+-. 0.1 23.9 .+-. 0.3 2.0 .+-. 0.1 24 > X > 0.7 2.3
.+-. 0.1 32 .+-. 0.2 0.7 .+-. 0.1 18.2 .+-. 0.3 2.0 .+-. 0.1 24
> X > 0.7 2.9 .+-. 0.1 40 .+-. 0.2 0.8 .+-. 0.1 9.1 .+-. 0.3
2.5 .+-. 0.1 24 > X > 0.7 Sample Ti, .mu.g/g Cr*, .mu.g/g
Cu*, .mu.g/g Zn, .mu.g/g K, .mu.g/g Mn, .mu.g/g Mo, .mu.g/g Name
.+-.95% CI .+-.95% CI .+-.95% CI .+-.95% CI .+-.95% CI .+-.95% CI
.+-.95% CI PC5 1.2 .+-. 0.1 3.3 .+-. 0.3 3.3 .+-. 0.5 5.7 .+-. 0.3
1.7 .+-. 0.3 0.4 .+-. 0.1 1.1 > X > 0.3 0.4 .+-. 0.1 3.3 .+-.
0.3 2.7 .+-. 0.5 16.9 .+-. 0.3 3.3 .+-. 0.2 0.4 .+-. 0.1 1.1 > X
> 0.3 0.5 .+-. 0.1 4.9 .+-. 0.3 3.5 .+-. 0.5 17.4 .+-. 0.3 5.4
.+-. 0.2 0.6 .+-. 0.1 1.1 > X > 0.3 PEI8.5 0.4 .+-. 0.1 191
.+-. 0.5 2.2 > X > 1.0 9.5 .+-. 0.3 1.8 .+-. 0.3 2.5 .+-. 0.1
1.1 > X > 0.3 0.3 .+-. 0.1 257 .+-. 0.5 2.3 .+-. 0.5 11.5
.+-. 0.3 2.2 .+-. 0.3 3.1 .+-. 0.1 1.1 .+-. 0.3 PEI7.2 .03 .+-. 0.1
206 .+-. 0.5 2.6 .+-. 0.5 7.8 .+-. 0.3 2.3 .+-. 0.3 3.3 .+-. 0.1
1.1 .+-. 0.3 0.3 .+-. 0.1 213 .+-. 0.5 2.6 .+-. 0.5 10.9 .+-. 0.3
1.7 .+-. 0.3 3.2 .+-. 0.1 1.2 .+-. 0.3 PC4 0.4 .+-. 0.1 1.6 .+-.
0.3 <1 5.6 .+-. 0.3 1.3 > X > 0.4 <0.2 1.1 > X >
0.3 0.3 .+-. 0.1 1.3 .+-. 0.1 <1 6.6 .+-. 0.3 1.3 > X >
0.4 <0.2 <0.3 0.4 .+-. 0.1 1.2 > X > 0.4 <1 7.1 .+-.
0.3 1.3 > X > 0.4 <0.2 <0.3 PC5, made on lab PRISM
extrusion line, 0.5 lb/hr, 5.4 ft/min, ~25 micron PEI8.5, made on
lab PRISM extrusion line, 0.4 lb/hr, 9 ft/min, 8.5 micron, 475
V/micron PEI7.2, Ultem 1000, PRISM extrusion line, 0.3 lb/hr, 9
ft/min, 7.2 micron, 553 V/micron PC4, extruded 6 micron film, 711
V/micron. *Cr and especially Cu could be partially lost after
ashing, thus their results are for information only.
[0113] Results indicate that some impurities are not uniformly
distributed in the samples. For the case of the PC4 polycarbonate
film, which is the same film described in Table 4 above, these
results were consistent with the relatively high values of
dielectric breakdown strength measured in this same film (Table 5
above).
Example 2
[0114] The film of PC4 described in Table 4 was metallized and
wound into electrostatic film capacitors of about 13.5 microF. Two
roll pairs of extruded polycarbonate film were metalized with zinc
heavy edge and aluminum web electrodes. The Rolls were marked in
pairs as #3 & #4 and #2 & #5. The film in both roll pairs
was 6 micron thick and 100 mm wide. A series of capacitors were
automatically wound from each roll pair set.
[0115] Measurement of Breakdown Voltage:
[0116] Two capacitors from each roll pair set (units #1 and #5)
were ramped in 50 VDC steps, 90 seconds per step, until the unit
short circuited as monitored by Insulation Resistance using 500
megohm (or less) as the failure (breakdown point). The results are
reported on Tables 8 and 9.
TABLE-US-00008 TABLE 8 Breakdown Test Results Unit #1 Break-Down
Break-Down S/N Test (VDC) Test (VDC) 1 900 850 Voltage Rolls #2
& #5 Rolls #3 & #4 VDC IR (M.OMEGA.) IR (M.OMEGA.) 50 6,250
6,250 100 11,111 11,111 150 10,714 9,375 200 11,765 11,765 250
10,870 10,870 300 9,677 9,677 350 8,750 13,462 400 11,111 11,111
450 9,783 10,000 500 8,065 8,065 550 6,250 7,237 600 4,615 6,316
650 3,611 5,417 700 2,593 4,118 750 1,923 3,216 800 1,379 2,105 850
988 2 900 30 n/a
TABLE-US-00009 TABLE 9 Breakdown Test Results Unit #5 Break-Down
Break-Down S/N Test (VDC) Test (VDC) 5 850 900 Voltage Rolls #2
& #5 Rolls #3 & #4 VDC IR (M.OMEGA.) IR (M.OMEGA.) 50
16,666 16,666 100 16,666 14,285 150 21,428 16,666 200 22,222 16,666
250 22,727 17,857 300 23,076 15,000 350 20,588 15,909 400 20,000
15,384 450 15,517 11,842 500 11,627 10,204 550 9,322 7,857 600
7,058 6,382 650 5,327 5,200 700 3,846 3,977 750 2,788 2,952 800
1,550 2,156 850 220 1,534 900 n/a 78
Tables 8 and 9 show that the breakdown voltage of these capacitors
was between 850 V and 900V.
[0117] Insulation Resistance with Voltage:
[0118] Typically, based on historical ratings, 6 micron thick PC
film is rated at 200 VDC with a DWV requirement of 400 VDC. Three
other 13.5 microF capacitors were tested for dielectric
withstanding voltage (DWV) and measured for insulation resistance
at 400 VDC DWV/200 VDC IR; 600 VDC DWV/300 VDC IR; and 800 VDC
DWV/400 VDC IR to compare the extruded PC film performance to
typical solvent cast PC results (Table 10).
TABLE-US-00010 TABLE 10 Breakdown Test Results Insulation
Resistance vs Voltage. Rolls #2 & #5 Rolls #3 & #4 Unit
Break-Down Break-Down S/N Test (VDC) Test (VDC) 1 900 850 Unit IR
AT Rolls #2 & #5 Rolls #3 & #4 S/N (VDC) IR (M.OMEGA.) IR
(M.OMEGA.) 2 200 66,700 66,700 3 300 13,600 10,700 4 400 1,000
400
[0119] Insulation Resistance with Temperature: Units #2, 3 and 4
from each of the two groups were measured for Insulation Resistance
at +25.degree. C., +85.degree. C., +105.degree. C. and +125.degree.
C., and three different voltages, 200 VDC, 300 VDC and 400 VDC
(Table 11A, 11B and 11C)
TABLE-US-00011 TABLE 11A Temperature Effects on IR (M.OMEGA.) at
200 VDC Temperature Temperature Temperature Temperature Rolls
(.degree. C.) 25 (.degree. C.) (.degree. C.) (.degree. C.) Section
S/N4 25 85 105 125 Rolls #2 & #5 64,500 7,200 4,200 1,900 Rolls
#3 & #4 69,000 9,600 6,700 4,900
TABLE-US-00012 TABLE 11B Temperature Effects on IR (M.OMEGA.) at
300 VDC Temperature Temperature Temperature Temperature Rolls
(.degree. C.) 25 (.degree. C.) (.degree. C.) (.degree. C.) Section
S/N3 25 85 105 125 Rolls #2 & #5 77,000 4,800 3,100 1,700 Rolls
#3 & #4 79,000 8,500 5,400 4,100
TABLE-US-00013 TABLE 11C Temperature Effects on IR (M.OMEGA.) at
400 VDC Temperature Temperature Temperature Temperature Rolls
(.degree. C.) 25 (.degree. C.) (.degree. C.) (.degree. C.) Section
S/N2 25 85 105 125 Rolls #2 & #5 Shorted N/A N/A N/A Rolls #3
& #4 57,000 5,900 4,900 2,100
[0120] The purpose of the following Examples is to demonstrate the
performance of copolyestercarbonates. Six copolyestercarboantes,
designated CPC1, CPC2, CPC3, CPC4, CPC5, and CPC6, were used in the
following examples. Further details on the composition of these
copolyestercarbonates are provided in Table 1 above, in the
following discussion and in Table 12, below.
[0121] CPC1 is a copolycarbonate of 67 mole % Bisphenol A and 33
mole % 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one.
[0122] CPC2 is a branched Bisphenol A polycarbonate with
hydroxybenzonitrile endgroups.
[0123] CPC3 is a polyestercarbonate with about 19 mole %
resorcinol, an iso and tere (1:1) phthalate ester linkages, 6 mole
% resorcinol carbonate linkages and about 75 mole % BPA carbonate
linkages. Mw .about.30,000.
[0124] CPC4 is a copolycarbonate with about 80 mole % resorcinol
iso and tere (1:1) phthalate ester linkages, 10 mole % resorcinol
carbonate linkages and about 10 mole % BPA carbonate linkages.
Mw.about.21,000
[0125] CPC5 is a BPA copolyester carbonate containing about 80 mole
% of a 93:7 mixture iso and tere phthalate ester groups and the
remainder BPA carbonate groups, Mw.about.28,000.
[0126] CPC6 is a BPA copolyester carbonate containing about 60 mole
% of a 50:50 mixture iso and tere phthalate ester groups and the
remainder BPA carbonate groups.
TABLE-US-00014 TABLE 12 Copolyester- Isophthalic/Terephthalic
carbonate % Ester ratio Phenol CPC 3 90 50/50 Resorcinol CPC 4 20
50/50 Resorcinol CPC 5 80 93/7 Bisphenol A CPC 6 60 50/50 Bisphenol
A
[0127] Samples of these materials were evaluated according to the
testing procedures summarized above, and the results are reported
on Table 13.
TABLE-US-00015 TABLE 13 Breakdown Glass strength/std Dissipation
Energy Transition Poly- dev Dielectric Factor Density Temp mer
(V/micron) constant(***) (%)(***) (J/cc) (.degree. C.) PC1 804/99
3.05 0.35 8.7 152 CPC1 738/178 3.23 0.71 7.8 196 CPC2 801/165 3.2
0.33 9.1 140 CPC3 636/75 3.5 0.82 6.3 136 CPC4 660/95 3.3 0.65 6.4
141 CPC5 766/149 3.55 0.96 9.2 177 CPC6 692/149 3.22 0.37 6.8 171
(***)These tests were conducted on compression molded samples
prepared as described in the procedure above.
[0128] The copolyestercarbonates demonstrated high average values
for Breakdown Strength (.about.650-800 V/micron). The Dielectric
Constant values for the copolyestercarbonates were uniformly equal
to or better than PC1, a polycarbonate evaluated above. Three
coplyestercarbonates, CPC1, CPC5, and CPC6 demonstrated excellent
overall performance on the electrical properties and exhibited high
Tg values and were further evaluated for film properties,
below.
[0129] Surface Roughness of Extrusion Films--Films of CPC1, CPC5
and CPC6 were evaluated as described in the procedure above, and
the results are shown on Table 14 a, and 14 b, below, on which the
values reported are in microns.
TABLE-US-00016 TABLE 14a Film Side 1 Ra Side 2 Ra Side 1 + Side 2
Ra CPC5 0.0266 0.0056 0.0490 0.0011 0.0378 0.0128 CPC6 0.0117
0.0037 0.0173 0.0082 0.0145 0.0065 CPC1 0.0056 0.0005 0.0089 0.0043
0.0073 0.0033
TABLE-US-00017 TABLE 14b Film Side 1 Rq Side 2 Rq Side 1 + Side 2
Rq CPC5 0.0346 0.0070 0.0707 0.0054 0.0526 0.0346 CPC6 0.0164
0.0061 0.0224 0.0100 0.0194 0.0164 CPC1 0.0077 0.0012 0.0112 0.0054
0.0095 0.0077
[0130] These results showed that the average roughness values were
under 0.04 microns for both sides.
[0131] Table 15 shows the dielectric breakdown strength of the film
of CPC1 at 20 sites on the film.
TABLE-US-00018 TABLE 15 Breakdown Breakdown Thickness Voltage
Strength Site (micron) (k-VDC) (V/micron) 1 11.5 12.44 1081 2 11.5
10.09 874 3 12.3 10.55 857 4 10.3 9.25 898 5 11.4 10.54 925 6 9.50
8.65 911 7 9.13 6.72 736 8 7.42 7.62 1027 9 7.81 7.15 916 10 7.79
7.46 957 11 8.91 6.74 756 12 11.1 8.03 721 13 10.0 8.63 860 14 8.83
9.83 1113 15 8.51 8.00 941 16 9.06 8.02 885 17 12.4 11.19 902 18
11.5 11.56 1004 19 10.8 10.51 973 20 10.0 10.37 1036 Mean 10.00
9.17 919 StDev 1.54 1.70 106
[0132] These results showed that the film of CPC1 had an average
breakdown strength in excess of 900 V/micron with a standard
deviation of 106 V/micron and failed at an average voltage of about
9,170 VDC.
[0133] Table 16 shows the dielectric breakdown strength of the film
of CPC5 at 20 sites on the film.
TABLE-US-00019 TABLE 16 Breakdown Breakdown Thickness Voltage
Strength Site (micron) (k-VDC) (V/micron) 1 10.7 11.85 1107 2 10.9
10.06 927 3 11.2 10.56 945 4 10.6 11.19 1061 5 8.30 9.27 1117 6
10.7 6.73 627 7 7.36 9.18 1247 8 9.16 9.27 1012 9 9.30 8.03 864 10
10.5 7.85 748 11 13.9 10.49 753 12 8.08 8.63 1068 13 8.82 8.64 980
14 9.15 7.12 778 15 8.17 8.58 1050 16 9.99 12.46 1248 17 13.5 10.46
777 18 9.70 9.27 956 19 10.0 10.54 1052 20 10.4 8.01 773 Mean 10.01
9.41 955 StDev 1.65 1.53 172
[0134] These results showed that the film of CPC1 had an average
breakdown strength in excess of 900 V/micron with a standard
deviation of 172 V/micron and failed at an average voltage of about
9,410 VDC.
[0135] Table 17 shows the dielectric breakdown strength of the film
of CPC6 at 20 sites on the film.
TABLE-US-00020 TABLE 17 Breakdown Breakdown Thickness Voltage
Strength Site (micron) (k-VDC) (V/micron) 1 7.16 6.08 849 2 9.77
8.61 881 3 11.1 9.24 834 4 10.3 8.54 829 5 8.00 7.39 924 6 8.43
6.73 798 7 10.3 10.52 1022 8 11.1 9.24 832 9 12.7 11.28 891 10 15.0
15.16 1009 11 15.6 15.68 1008 12 15.0 13.09 873 13 16.1 13.08 811
14 14.0 6.75 484 15 11.2 10.53 939 16 9.50 8.63 908 17 7.67 6.71
875 18 9.20 5.41 588 19 8.26 6.15 744 20 10.4 8.31 796 Mean 11.04
9.36 845 StDev 2.79 3.01 130
[0136] These results showed that the film of CPC1 had an average
breakdown strength in excess of 840 V/micron with a standard
deviation of 130 V/micron and failed at an average voltage of about
9,360 VDC. Advantageously, films made in accordance to our
invention exhibited a thickness of more than 0 and less than 7
micrometers, a variation of the thickness of the film of +/-10% or
less of the thickness of the film, a surface roughness average of
less than +/-3% of the average thickness of the film as measured by
optical profilometry; a dielectric constant at 1 kHz and room
temperature of at least 2.7; a dissipation factor at 1 kHz and room
temperature of 1% or less; and a breakdown strength of at least 300
Volt/micrometer.
[0137] All cited patents, patent applications, and other references
are incorporated herein by reference in their entirety.
[0138] Although the present invention has been described in detail
with reference to certain preferred versions thereof, other
variations are possible. Therefore, the spirit and scope of the
appended claims should not be limited to the description of the
versions contained therein.
* * * * *