U.S. patent application number 10/869231 was filed with the patent office on 2006-04-13 for flame retardant thermoplastic films and methods of making the same.
Invention is credited to Robert R. Gallucci, William Kernick, Jeroen Vervoort.
Application Number | 20060078751 10/869231 |
Document ID | / |
Family ID | 34278651 |
Filed Date | 2006-04-13 |
United States Patent
Application |
20060078751 |
Kind Code |
A9 |
Gallucci; Robert R. ; et
al. |
April 13, 2006 |
Flame retardant thermoplastic films and methods of making the
same
Abstract
A film can comprise greater than or equal to about 95 wt %
thermoplastic resin and about 0.001 wt % to about 5.0 wt %
sulfonate salt, based on a total weight of the film, and have a
UL-94 rating of VTM-0, wherein the thermoplastic resin is selected
from the group consisting of polyimide, polysulfone, and
copolymers, reaction products, and combinations comprising at least
one of the foregoing thermoplastic resins.
Inventors: |
Gallucci; Robert R.; (Mount
Vernon, IN) ; Kernick; William; (Evansville, IN)
; Vervoort; Jeroen; (Bergen op Zoom, NL) |
Correspondence
Address: |
CANTOR COLBURN, LLP
55 GRIFFIN ROAD SOUTH
BLOOMFIELD
CT
06002
US
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20050048299 A1 |
March 3, 2005 |
|
|
Family ID: |
34278651 |
Appl. No.: |
10/869231 |
Filed: |
June 15, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60499215 |
Aug 28, 2003 |
|
|
|
Current U.S.
Class: |
428/473.5 ;
524/167 |
Current CPC
Class: |
H05K 1/0393 20130101;
Y10T 428/31721 20150401; Y10T 428/31681 20150401; H05K 1/0373
20130101; H05K 2201/0129 20130101; C08K 5/42 20130101; H05K
2203/122 20130101; C08K 5/42 20130101; C08L 81/06 20130101; C08K
5/42 20130101; C08L 79/08 20130101 |
Class at
Publication: |
428/473.5 ;
524/167 |
International
Class: |
B32B 27/00 20060101
B32B027/00; C08K 5/42 20060101 C08K005/42 |
Claims
1. A film, comprising: greater than or equal to about 95 wt %
thermoplastic resin, based on a total weight of the film, wherein
the thermoplastic resin is selected from the group consisting of
polyimide, polysulfone, and copolymers, reaction products, and
combinations comprising at least one of the foregoing thermoplastic
resins; about 0.001 wt % to about 5.0 wt % sulfonate salt, based on
the total weight of the film; and a UL-94 rating of VTM-0.
2. The film of claim 1, further comprising a percent transmission
of greater than or equal to about 50% as measured by ASTM
D1003.
3. The film of claim 2, wherein the percent transmission is greater
than or equal to about 75%
4. The film of claim 2, further comprising a haze of less than or
equal to about 10% as measured by ASTM D1003.
5. The film of claim 1, further comprising less than or equal to
about 1,000 ppm bromine.
6. The film of claim 1, further comprising less than or equal to
about 1,000 ppm chlorine.
7. The film of claim 1, further comprising a T.sub.g of about
180.degree. C. to about 350.degree. C. as measured by ASTM
D3418.
8. The film of claim 1, further comprising a fluoropolymer in an
amount of about 0.01 wt % to about 2.0 wt %, based on the total
weight of the film.
9. The film of claim 1, wherein the sulfonate salt is selected from
the group consisting of Formulas (I), (II), and (III), and mixtures
comprising at least one sulfonate salt of Formula (I), (II), and
(III): ##STR10## where R' is C.sub.1-C.sub.40 alkyl, or
C.sub.1-C.sub.40 fluoroalkyl; R is independently for each
substitution a one to forty carbon atom alkyl group or alkyl-,
arylalkyl- or aromatic ether group, M is a metal selected from the
group consisting of an alkali metal, an alkaline earth metal, and
combinations comprising at least one of the foregoing metals; x is
the oxidation state of M; and j, k, m and n are each integers of 0
to 5, wherein j+k is at least 1, j+m is less than or equal to 5,
and k+n is less than or equal to 5; D is --SO.sub.2-- or --O--.
10. The film of claim 9, wherein the sulfonate salt is selected
from the group consisting of perfluorobutyl potassium sulfonate
salt, potassium sulfone sulfonate, sodium dodecylbenzene sulfonate,
sodium benzene sulfonate, and combinations comprising at least one
of the foregoing sulfonate salts.
11. The film of claim 1, wherein the sulfonate salt comprises a
perfluoroalkyl (alkali metal/alkaline earth metal) sulfonate
salt.
12. The film of claim 10, wherein the sulfonate salt comprises
perfluorobutyl potassium sulfonate salt.
13. The film of claim 10, wherein the perfluroalkyl (alkali
metal/alkaline earth metal) sulfonate salt has less than or equal
to eight carbon atoms.
14. The film of claim 1, comprising about 0.025 wt % to about 3.0
wt % of the sulfonate salt.
15. The film of claim 14, comprising about 0.05 wt % to about 1.0
wt % of the sulfonate salt.
16. The film of claim 1, wherein the film comprises a polyimide
selected from the group consisting of polyetherimide,
polyetherimide sulfones, and reaction products, copolymers, and
combinations comprising at least one of the foregoing
polyimides.
17. The film of claim 1, wherein the thermoplastic resin comprises
polysulfones.
18. The film of claim 17, wherein the polysulfone is selected from
the group consisting of polyether sulfones, polyaryl ether
sulfones, polyetherethersulfones, polyphenylene ether sulfones,
polyetherimide sulfone, and reaction products, copolymers, and
combinations comprising at least one of the foregoing
polysulfones.
19. The film of claim 1, wherein the thermoplastic resin comprises
polyetherimide.
20. The film of claim 1, wherein the film has a thickness of about
50 micrometers to about 300 micrometers.
21. The film of claim 1, wherein the film is metallized.
22. A film, comprising the reaction product of: greater than or
equal to about 95 wt % thermoplastic resin, based on a total weight
of the film, wherein the thermoplastic resin is selected from the
group consisting of polyimide, polysulfone, and copolymers,
reaction products, and combinations comprising at least one of the
foregoing thermoplastic resins; and about 0.001 wt % to about 5.0
wt % sulfonate salt, based on the total weight of the film; and
wherein the film has a UL-94 rating of VTM-0 for film thicknesses
of 50 micrometers to 200 micrometers.
23. A method for producing a film, comprising: melting a
thermoplastic resin and a sulfonate salt to form a melt, wherein
the thermoplastic resin is selected from the group consisting of
polyimide, polysulfone, and copolymers, reaction products, and
combinations comprising at least one of the foregoing thermoplastic
resins, and wherein the thermoplastic resin is present in an amount
of greater than or equal to about 95 wt %, and the sulfonate salt
is present in an amount of about 0.001 wt % to about 5.0 wt %,
based upon the total weight of the melt; and passing the melt
through a die to produce the film.
24. The method of claim 23, further comprising applying a vacuum to
the melt at a vacuum pressure of less than or equal to about 125
mbars absolute.
25. The method of claim 24, wherein the vacuum pressure is about
110 mbars absolute to about 125 mbars absolute.
26. A method for producing a thermoplastic film using melt
processing, comprising: melting a thermoplastic resin to form a
melt; applying a sufficient vacuum to the melt to reduce a film
total flame out time, determined in accordance with UL-94, by
greater than or equal to about 10 seconds as compared to an
original total flame out time attained from a film having the same
composition and an application of a vacuum of greater than or equal
to 250 mbar; and passing the melt through a die to produce the
film.
27. The method of claim 26, wherein the vacuum pressure is about
110 mbars absolute to about 125 mbars absolute.
28. The method of claim 26, wherein the film total flame out time
is reduced by greater than or equal to about 50 seconds.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Provisional
Application Ser. No. 60/499,215, filed Aug. 28, 2003, with is
incorporated herein in its entirety.
BACKGROUND OF THE INVENTION
[0002] Since high T.sub.g (glass transition temperature)
thermoplastic resins (e.g., T.sub.g of greater than or equal to
about 180.degree. C.) are processed at high temperatures, many
standard additives that are used to flame retard other resins are
unstable, decomposing under the high process temperatures needed to
melt process the viscous high T.sub.g amorphous thermoplastics. The
decomposition of standard flame retardant (FR) additives during
melt processing, as well as the detrimental effects such
decomposition products can have upon the resin and the equipment,
is a problem. This is true of amorphous polyetherimide (PEI) and
polysulfone (PSU) resins that have high T.sub.g and high viscosity
making them more difficult to melt process than crystalline resins
or lower T.sub.g amorphous resins. Efforts to improve the flame
retardancy of PEI by forming blends with additional materials such
as brominated polycarbonate, aliphatic bominated or chlorinated
compounds, and hydrated inorganic compounds like aluminum
trihydrate and some alkyl phosphates, are ineffective due to
decomposition or volatilization of the flame retardant
additive.
[0003] A particular flame retardancy deficiency has been noted in
PEI and polysulfone films having a thickness of 25 micrometers to
300 micrometers (e.g., films used in applications such as
electronics). Hence, PEI and polysulfone films have need of
improved flame retardant performance. These thin films have a
relatively high surface area that is exposed to air, making the
combustion process more favorable than in thicker sections.
Electronic specifications often require the film to exhibit
sufficient flame retardancy such as that specified in UL-94
(Underwriter's Laboratory Bulletin 94 entitled "Tests for
Flammability of Plastic Materials, UL-94"). A rating of VTM-0 is
desirable in many applications. Polyetherimide and polysulfone thin
films, however, often only attain a UL-94 rating of VTM-1 or VTM-2.
Various unsuccessful attempts have been made at improving the flame
retardancy rating and ignition resistance of the film while
retaining the melt processability, good mechanical and electrical
properties, and transparency of the PEI, PSU, and polyethersulfone
(PES) films. Therefore, there remains a need to produce
polyetherimide and polysulfone films having a thickness of about 25
micrometers to about 300 micrometers while attaining a UL-94 rating
of VTM-0.
BRIEF DESCRIPTION OF THE INVENTION
[0004] Disclosed herein are films and methods of making the same.
In one embodiment, a film can comprise greater than or equal to
about 95 wt % thermoplastic resin and about 0.001 wt % to about 5.0
wt % sulfonate salt, based on a total weight of the film, and have
a UL-94 rating of VTM-0, wherein the thermoplastic resin is
selected from the group consisting of polyimide, polysulfone, and
copolymers, reaction products, and combinations comprising at least
one of the foregoing thermoplastic resins.
[0005] In another embodiment, a film can comprise the reaction
product of greater than or equal to about 95 wt % thermoplastic
resin and about 0.001 wt % to about 5.0 wt % sulfonate salt, based
on a total weight of the film, and have a UL-94 rating of VTM-0,
wherein the thermoplastic resin is selected from the group
consisting of polyimide, polysulfone, and copolymers, reaction
products, and combinations comprising at least one of the foregoing
thermoplastic resins.
[0006] In one embodiment, the method for producing a film using
melt processing, comprises: melting a thermoplastic resin and a
sulfonate salt to form a melt and passing the melt through a die to
produce the film, wherein the thermoplastic resin is selected from
the group consisting of polyimide, polysulfone, and copolymers,
reaction products, and combinations comprising at least one of the
foregoing thermoplastic resins, and wherein the thermoplastic resin
is present in an amount of greater than or equal to about 95 wt %,
and the sulfonate salt is present in an amount of about 0.001 wt %
to about 5.0 wt %, based upon the combined weight of the melts.
[0007] The above described and other features are exemplified by
the following detailed description.
DESCRIPTION OF THE DRAWINGS
[0008] Referring to the drawings, which are meant to be exemplary
and not limiting:
[0009] FIG. 1 is a graphical illustration of total flame out time
for all samples tested versus thickness and vacuum pressure for PEI
film as determined in accordance with UL-94 testing standards;
[0010] FIG. 2 is a graphical illustration of maximum afterflame
time versus thickness and vacuum pressure, this is the highest
flame out time for an individual sample among the ten films tested,
for a PEI film, as determined in accordance with UL-94 testing
standards; and
[0011] FIG. 3 is a graphical illustration of total flame out time
for all samples tested versus thickness and vacuum pressure (as
determined in accordance with UL-94 testing standards) to
illustrate the effect of vacuum and perfluoroalkyl sulfonate
addition in a PEI film. Note that by use of the sulfonate salt
total after flame values can be achieved independent of vacuum.
DETAILED DESCRIPTION OF THE INVENTION
[0012] Disclosed herein is a composition and method for making a
flame retardant thermoplastic amorphous resin. It is noted that the
terms "a" and "an" herein do not denote a limitation of quantity,
but rather denote the presence of at least one of the referenced
item. Additionally, all ranges disclosed herein are inclusive and
combinable (e.g., the ranges of "up to 25 wt %, with 5 wt % to 20
wt % desired," are inclusive of the endpoints and all intermediate
values of the ranges of "5 wt % to 25 wt %," etc.).
[0013] The thermoplastic resin, for example, can be polyimide
(e.g., polyetherimide (PEI), or the like), polyetherimide sulfones
(PEIS), polyimide copolymers, polysulfone (PSU), polyethersulfone
(PES), polyphenylene sulfone (PPSU), and copolymers, reaction
products, and combinations comprising at least one of the foregoing
thermoplastic resins. Specifically, the thermoplastic resin can
have a high purity (e.g., greater than or equal to about 95 wt % of
the thermoplastic resin based on the total weight of the
composition), and a high T.sub.g (i.e., greater than or equal to
about 180.degree. C., such as a T.sub.g of about 180.degree. C. to
about 350.degree. C.). The desired flame retardancy can be imparted
via the addition of a sulfonate salt and/or via the use of a vacuum
pressure of less than or equal to about 125 millibars (mbar)
absolute during the formation of the film. Vacuum treatment of the
resin can be performed during a melt processing of the resin to
prepare the film. This film, although having a thickness of about
25 micrometers to about 350 micrometers (desirably about 50
micrometers to about 250 micrometers), attains a UL-94 rating of
VTM-0.
[0014] There are two aspects of the UL-94 measurement of
flammability discussed here. The total flameout time (TFOT) or
total after flame time (TAFT) is the sum of the time, in seconds
(s), that all the samples remained ignited after two separate
applications of a flame as described in UL-94 VTM test. The usual
VTM test involves 5 samples. The average total flameout time
(ATFOT) is the TFOT divided by the number of samples. The ATFOT is
a per specimen value. The TFOT or TAFT is an aggregate value of all
samples tested. In either case shorter time periods indicate better
flame resistance, i.e., the flame went out faster. For a UL-94
VTM-0 rating the total flaming combustion time (TFOT or TFAT) for
all five samples, each having two applications of flame, will not
exceed 50 seconds. Also no individual sample will have a combustion
time exceeding 10 seconds. Individual combustion time is reflected
in the ATFOT.
[0015] The sulfonate salt can be any sulfonate salt capable of
attaining a VTM-0 rating in high T.sub.g thermoplastic resins for
all film thicknesses of about 25 micrometers to 200 about
micrometers, and even to about 300 micrometers. Exemplary sulfonate
salts include fluoroalkyl sulfonate salts, aryl sulfonate salts,
alkyl aryl sulfonate salts, and combinations comprising at least
one of the foregoing sulfonate salts. In some particular
embodiments suitable salts of sulfonic acids include those having
the following formulas: ##STR1## where R' may be C.sub.1- C.sub.40
alkyl, or C.sub.1-C.sub.40 fluoroalkyl, desirably C.sub.4-C.sub.8
perfluoroalkyl group(s). R is, independently for each substitution,
a one to forty carbon atom alkyl group or alkyl-, arylalkyl- or
aromatic ether group; M is an alkali metal(s), an alkaline earth
metal(s), or a combination comprising at least one of the foregoing
metals; x is the oxidation state of the metal, M; and j, k, m, and
n are each integers from 0 to 5 subject to the limitation that j+k
is at least 1 and subject to the further limitation that j+m is
less than or equal to 5 and k+n is less than or equal to 5. In some
particular embodiments j is zero and k is one. R can be an alkyl
group having 3 to 40 carbon atoms, specifically 4 to 20 carbon
atoms, and more specifically 4 to 12 carbon atoms. The linking
group D is typically --SO.sub.2- or --O--. The metals can be the
Group IA or Group IIA metals in the Periodic Table of Elements, and
more specifically, sodium and/or potassium.
[0016] In some particular embodiments suitable sulfonate salts
comprise perfluoroalkyl (alkali metal/alkaline earth metal)
sulfonate salts, e.g., perfluorobutyl potassium sulfonate salt
(KPFBS). Other possible sulfonate salts include potassium sulfone
sulfonate (KSS), sodium benzene sulfonate, and sodium
dodecylbenzene sulfonate (NaDBS). Desirably, the perfluoroalkyl
alkaline metal/alkaline earth metal sulfonate salts have less than
or equal to eight carbon atoms. Mixtures comprising at least one of
any of the above mentioned sulfonate salts may also be
employed.
[0017] Generally, the sulfonate salt(s) are present in the
composition in an amount of less than or equal to about 5.0 weight
percent (wt %), e.g., about 0.001 wt % to about 5.0 wt %, based
upon the total weight of the composition, specifically, about 0.005
wt % to about 3.0 wt %, more specifically about 0.01 wt % to about
2.0 wt %, even more specifically about 0.01 wt % to about 1.0 wt %,
yet more specifically about 0.025 wt % to about 0.5 wt %, and even
more specifically about 0.025 wt % to about 0.08 wt %. All weight
percents discussed herein are based upon the total weight of the
film unless otherwise specified.
[0018] The composition may also optionally include a fluoropolymer
in an amount effective to provide anti-drip properties to the resin
composition, e.g., of about 0.01 wt % to about 2.0 wt %
fluoropolymer. Addition of the fluoropolymer, while making the film
less prone to dripping during application of a flame, may increase
haze and reduce transparency of a clear resin. Some possible
examples of suitable fluoropolymers and methods for making such
fluoropolymers are set forth, for example, in U.S. Pat. Nos.
3,671,487, 3,723,373, and 3,383,092. Fluoropolymers include
homopolymers and copolymers that comprise structural units derived
from one or more fluorinated alpha-olefin monomers. The term
"fluorinated alpha-olefin monomer" means an alpha-olefin monomer
that includes at least one fluorine atom substituent. Some
fluorinated alpha-olefin monomers include, for example,
fluoroethylenes such as, for example, CF.sub.2.dbd.CF.sub.2,
CHF.dbd.CF.sub.2, CH.sub.2.dbd.CF.sub.2, and CH.sub.2.dbd.CHF;
and/or fluoropropylenes such as, for example,
CF.sub.3CF.dbd.CF.sub.2, CF.sub.3CF.dbd.CHF,
CF.sub.3CH.dbd.CF.sub.2, CF.sub.3CH.dbd.CH.sub.2,
CF.sub.3CF.dbd.CHF, CHF.sub.2CH.dbd.CHF, and
CF.sub.3CF.dbd.CH.sub.2.
[0019] Some fluorinated alpha-olefin copolymers include copolymers
comprising structural units derived from two or more fluorinated
alpha-olefin monomers such as, for example,
poly(tetrafluoroethylene-hexafluoroethylene), and copolymers
comprising structural units derived from one or more fluorinated
monomers and one or more non-fluorinated monoethylenically
unsaturated monomers that are copolymerizable with the fluorinated
monomers such as, for example,
poly(tetrafluoroethylene-ethylene-propylene) copolymers.
Non-fluorinated monoethylenically unsaturated monomers include for
example, alpha-olefin monomers such as, for example, ethylene,
propylene, butene, and the like.
[0020] Polyimides have the general Formula (IV): ##STR2## wherein a
is more than 1, typically about 10 to about 1,000 or more, and can
specifically be about 10 to about 500; and wherein V is a
tetravalent linker without limitation, as long as the linker does
not impede synthesis or use of the polyimide. Suitable linkers
include, but are not limited to: (a) substituted or unsubstituted,
saturated, unsaturated or aromatic monocyclic and polycyclic groups
having about 5 to about 50 carbon atoms, (b) substituted or
unsubstituted, linear or branched, saturated or unsaturated alkyl
groups having 1 to about 30 carbon atoms; and combinations
comprising at least one of the foregoing linkers. Suitable
substitutions and/or linkers include, but are not limited to,
ethers, epoxides, amides, esters, and combinations comprising at
least one of the foregoing. Exemplary linkers include, but are not
limited to, tetravalent aromatic radicals of Formula (V), such as:
##STR3## wherein W is a divalent moiety such as --O--, --S--,
--C(O)--, --SO.sub.2--, --So--, -C.sub.yH.sub.2y- (y being an
integer of 1 to 5), and halogenated derivatives thereof, including
perfluoroalkylene groups, or a group of the Formula --O--Z--O--
wherein the divalent bonds of the --O-- or the --O--Z--O-- group
are in the 3,3', 3,4', 4,3', or the 4,4' positions, and wherein Z
includes, but is not limited, to divalent radicals of Formula (VI):
##STR4## wherein Q includes, but is not limited to, a divalent
moiety comprising --O--, --S--, --C(O)--, --SO.sub.2--, --SO--,
--C.sub.yH.sub.2y-- (y being an integer from 1 to 5), and
halogenated derivatives thereof, including perfluoroalkylene
groups.
[0021] R.sup.1 in formula (IV) includes, but is not limited to,
substituted or unsubstituted divalent organic radicals such as:
aromatic hydrocarbon radicals having about 6 to about 20 carbon
atoms and halogenated derivatives thereof; straight or branched
chain alkylene radicals having about 2 to about 20 carbon atoms;
cycloalkylene radicals having about 3 to about 20 carbon atoms; or
divalent radicals of the general formula (VII) ##STR5## wherein Q
is defined as above.
[0022] Exemplary classes of polyimides include, but are not limited
to, polyamidimides and polyetherimides, particularly those
polyetherimides that are melt processible, such as those whose
preparation and properties are described in U.S. Pat. Nos.
3,803,085 and 3,905,942.
[0023] Polyetherimide resins comprise more than 1, typically about
10 to about 1,000 or more, and more specifically about 10 to about
500 structural units, of the Formula (VIII): ##STR6## wherein T is
--O-- or a group of the Formula --O--Z--O-- wherein the divalent
bonds of the --O-- or the --O--Z--O-- group are in the 3,3', 3,4',
4,3', or the 4,4' positions, and wherein Z and R.sup.1 are defined
as described above.
[0024] The polyetherimide can be prepared by any of a variety of
methods, including the reaction of an aromatic bis(ether anhydride)
of the Formula (IX) ##STR7## with an organic diamine of the Formula
(X) H.sub.2N--R.sup.1--NH.sub.2 (X) wherein R.sup.1 and T are
defined in relation to Formulas (IV) and (VIII), respectively.
[0025] Examples of specific aromatic bis(ether anhydride)s and
organic diamines are disclosed, for example, in U.S. Pat. Nos.
3,972,902 and 4,455,410. Illustrative examples of aromatic
bis(ether anhydride)s of Formula (IX) include:
2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride;
4,4'bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride;
4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride;
4,4'-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride;
4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride;
2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride;
4,4'-bis(2,3-dicarboxyphenoxy)diphenyl ether dianhydride;
4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sulfide dianhydride;
4,4'-bis(2,3-dicarboxyphenoxy)benzophenone dianhydride;
4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sulfone dianhydride;
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl-2,2-propane
dianhydride;
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl ether
dianhydride;
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl sulfide
dianhydride;
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)benzophenone
dianhydride and
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl sulfone
dianhydride, as well as mixtures comprising at least two of the
foregoing. More specifically, the dianhydride can be
bis[3,4dicarboxyphenoxy) phenyl]propane dianhydride (BPA-DA),
pyromellitic dianhydride, oxydiphthalic anhydride (ODPA), as well
as isomers and combinations comprising at least one of the
foregoing dianhydrides. Specifically, aryl dianhydrides free of
benzylic protons are preferred for better melt stability.
[0026] The bis(ether anhydride)s can be prepared by the hydrolysis,
followed by dehydration, of the reaction product of a nitro
substituted phenyl dinitrile with a metal salt of dihydric phenol
compound in the presence of a dipolar, aprotic solvent. A preferred
class of aromatic bis(ether anhydride)s included by Formula (IX)
above includes, but is not limited to, compounds wherein T is of
the Formula (XI): ##STR8## and the ether linkages, for example, can
be in the 3,3', 3,4', 4,3', or 4,4' positions, and mixtures
comprising at least one of the foregoing, and where Q is as defined
above.
[0027] Any diamino compound may be employed. Examples of suitable
compounds are ethylenediamine, propylenediamine,
trimethylenediamine, diethylenetriamine, triethylenetertramine,
hexamethylenediamine, heptamethylenediamine, octamethylenediamine,
nonamethylenediamine, decamethylenediamine, 1,12-dodecanediamine,
1,18-octadecanediamine, 3-methylheptamethylenediamine,
4,4-dimethylheptamethylenediamine, 4-methylnonamethylenediamine,
5-methylnonamethylenediamine, 2,5-dimethylhexamethylenediamine,
2,5-dimethylheptamethylenediamine, 2,2-dimethylpropylenediamine,
N-methyl-bis (3-aminopropyl) amine, 3-methoxyhexamethylenediamine,
1,2-bis(3-aminopropoxy) ethane, bis(3-aminopropyl) sulfide,
1,4-cyclohexanediamine, bis-(4-aminocyclohexyl) methane,
m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene,
2,6-diaminotoluene, m-xylylenediamine, p-xylylenediamine,
2-methyl-4,6-diethyl-1,3-phenylene-diamine, 5-methyl-4,6-diethyl-
1,3 -phenylene-diamine, benzidine, 3,3 '-dimethylbenzidine,
3,3'-dimethoxybenzidine, 1,5-diaminonaphthalene, bis(4-aminophenyl)
methane, bis(2-chloro-4-amino-3, 5-diethylphenyl) methane,
bis(4-aminophenyl) propane, 2,4-bis(b-amino-t-butyl) toluene,
bis(p-b-amino-t-butylphenyl) ether, bis(p-b-methyl-o-aminophenyl)
benzene, bis(p-b-methyl-o-aminopentyl) benzene,
1,3-diamino-4-isopropylbenzene, bis(4-aminophenyl) sulfide, bis
(4-aminophenyl) sulfone, and bis(4-aminophenyl) ether. Mixtures
comprising at least one of these compounds may also be present. The
diamino compounds can, specifically, be aromatic diamines. More
specifically, the diamino compounds can be m- and
p-phenylenediamine, diamino diphenyl sulfone (DDS) and mixtures
comprising at least one of these compounds. Specifically, aryl
diamines free of benzylic protons are preferred for better melt
stability.
[0028] The polyetherimide resin can comprise structural units
according to Formula (VIII) wherein each R.sup.1 is independently
diphenyl sulfone, p-phenylene or m-phenylene or a mixture thereof
and T is a divalent radical of the Formula (XII): ##STR9##
[0029] Included among the many methods of making the polyimides,
particularly polyetherimides, are those disclosed in U.S. Pat. Nos.
3,847,867, 3,850,885, 3,852,242, 3,855,178, 3,983,093, and
4,443,591.
[0030] In general, the reactions can be carried out employing
various solvents, e.g., o-dichlorobenzene, m-cresol/toluene, and
the like, to effect a reaction between the anhydrides of Formula
(IX) and the diamines of Formula (X), at temperatures of about
100.degree. C. to about 250.degree. C. Alternatively, the
polyetherimide can be prepared by melt polymerization or
interfacial polymerization, e.g., melt polymerization of aromatic
bis(ether anhydride)s and diamines by heating a mixture of the
starting materials to elevated temperatures with concurrent
stirring and removal of water. Generally, melt polymerizations
employ temperatures of about 200.degree. C. to about 400.degree.
C.
[0031] Chain stoppers (such as mono anhydrides and mono amines) and
branching agents (such as tri- or tetra- functional amines or tri-
or tetra functional anhydrides, or tri- and tetra- functional
carboxylic acids) may also be employed in the reaction.
Specifically, end caps free of benzylic protons can be used for
better melt stability. When polyetherimide/polyimide copolymers are
employed, a dianhydride, such as pyromellitic anhydride or
oxydiphthalic anhydride, is used in combination with BPA-DA. The
polyetherimide resins can optionally be prepared from reaction of
an aromatic bis(ether anhydride) with an organic diamine in which
the diamine is present in the reaction mixture at less than or
equal about 0.5 molar excess, or more specifically less than or
equal to about 0.2 molar excess.
[0032] Generally, useful polyetherimides have a melt index of about
0.1 to about 10 grams per minute (g/min), as measured by American
Society for Testing Materials (ASTM) D1238 at 340-370.degree. C.,
using a 6.6 kilogram (kg) weight. The polymer should be dried prior
to testing melt index. The polyetherimide resin can have a weight
average molecular weight (Mw) of about 5,000 to about 100,000 grams
per mole (g/mole), more specifically a Mw of about 10,000 g/mole to
about 60,000 g/mole, as measured by gel permeation chromatography,
using a polystyrene standard. Such polyetherimide resins typically
have an intrinsic viscosity greater than about 0.2 deciliters per
gram (dl/g), preferably about 0.35 to about 0.7 dl/g measured in
m-cresol at 25.degree. C. Some such polyetherimides include, but
are not limited to, ULTEM XH6050 (a polyetherimide sulfones),
ULTEM.RTM. 1000, ULTEM.RTM. 1010, ULTEM.RTM. 1040, (all
commercially available from General Electric Advanced Materials),
or mixtures comprising at least one of the foregoing.
[0033] The polysulfones are thermoplastic polymers that possess a
number of attractive features such as high temperature resistance,
good electrical properties, and good hydrolytic stability. Various
polysulfones can be employed herein, such as polyether sulfones,
polyaryl ether sulfones, polyetherethersulfones, polyphenylene
ether sulfones, and the like, as well as copolymers, reaction
products, and combinations comprising at least one of the foregoing
polysulfones. A variety of polyaryl ether sulfones are commercially
available, including the polycondensation product of
dihydroxydiphenyl sulfone with dichlorodiphenyl sulfone, known as
polyethersulfone (PES) resin, and the polymer product of bisphenol
A (BPA) and dichlorodiphenyl sulfone, which is a polyethersulfone
sometimes referred to as polysulfone (PSF) resin. Polyphenylene
ether sulfone (PPSU) made from biphenol and dichloro diphenyl
sulfone can also be employed especially where high impact is
desired. A variety of polyether sulfone copolymers, for example
comprising bisphenol A and other bisphenols moieties and diphenyl
sulfone moieties in molar ratios other than 1:1, can also be
used.
[0034] Other polyaryl ether sulfones include polybiphenyl ether
sulfone resins, such as those available from Solvay S. A. Inc.
under the trademark of RADEL R resin. This resin may be described
as the polycondensation product of biphenol with
4,4'-dichlorodiphenyl sulfone and also described, for example, in
Canadian Patent No. 847,963.
[0035] Methods for the preparation of polysulfones include the
carbonate method and the alkali metal hydroxide method. In the
alkali metal hydroxide method, a double alkali metal salt of a
dihydroxy-substituted aromatic hydrocarbon is contacted with a
dihalobenzenoid compound in the presence of a dipolar, aprotic
solvent under substantially anhydrous conditions. In the carbonate
method at least one dihydroxy-substituted aromatic hydrocarbon and
at least one dihalobenzenoid compound are heated, for example, with
sodium carbonate or bicarbonate and a second alkali metal carbonate
or bicarbonate as disclosed, for example, in U.S. Pat. No.
4,176,222. Alternatively, the polybiphenyl ether sulfone, PSF and
PES resin components may be prepared by any of the variety of
methods used for the preparation of polyaryl ether resins.
Thermoplastic polyethersulfones and methods for their preparation
are also described, for example, in U.S. Pat. Nos. 3,634,355;
4,008,203; 4,108,837; and 4,175,175. Polysulfones made by any
process may be used to make the flame retardant films.
[0036] The weight average molecular weight of the polysulfone is
indicated by reduced viscosity data in an appropriate solvent such
as methylene chloride, chloroform, N-methyl pyrrolidinone, or the
like. The intrinsic viscosity of the polysulfone can be greater
than or equal to about 0.3 deciliters per gram (dl/g), typically
about 0.3 dl/g to about 1.5 dl/g, with greater than or equal to
about 0.4 dl/g preferred. Examples of some suitable polysulfones
are described, for example, in ASTM D6394. The above described
polysulfones and polysulfone copolymers may be employed alone or in
combinations comprising at least one of the foregoing.
[0037] The amount of the thermoplastic resin (e.g., polyimides,
polyetherimide sulfones, polysulfones, copolymers, and mixtures)
can be present in the composition in amounts of greater than or
equal to about 90 wt %, specifically greater than or equal to about
95 wt %, and more specifically greater than or equal to about 97 wt
%. Optionally, the composition can consist essentially of greater
than or equal to about 97 wt % thermoplastic resin and about 0.001
wt % to about 0.1 wt % sulfonate salt. In another embodiment, the
composition can comprise greater than or equal to about 97 wt %
thermoplastic resin, about 0.001 wt % to about 1.0 wt % sulfonate
salt, less than or equal to about 2,500 parts per million by weight
(ppm) bromine and/or less than or equal to about 2,500 ppm
chlorine, and optionally, about 0.01 wt % to about 2.0 wt %
fluoropolymer. More specifically, the composition (and film) can
comprise less than or equal to about 1,000 ppm bromine and/or less
than or equal to about 1,000 ppm chlorine.
[0038] The composition (i.e., the resin, the sulfonate salt, and
optionally the fluoropolymer) can be formed prior to the formation
of the film. For example, the composition can be prepared and
formed into pellets. The pellets may then be melt processed into
the desired film. To further enhance the flame retardancy of the
film, a vacuum can be employed during the melt processing wherein
the vacuum is at a pressure of less than or equal to about 125
mbars absolute. In this process, pellets (e.g., the composition or
just the resin pellets) are added to an extruder or the like. If
resin pellets are employed, the sulfonate salt (and optionally the
fluoropolymer) is preferably also added to the throat of the
extruder at the time of adding the resin pellets. Within the
extruder, the pellets are melt processed by heating to above the
glass transition temperature (T.sub.g) of the pellets. In one
embodiment, to facilitate processing and flow of the melt, the
pellets can be heated to about 250.degree. C. to about 325.degree.
C. It is desirable to dry the polyimide or polysulfone prior to
melt processing to remove any absorbed water or other volatile
species. Drying may be done under air, nitrogen or vacuum. Drying
temperatures may be, for example, about 125.degree. C. to about
175.degree.C.
[0039] A vacuum may optionally be applied to the melt to remove
gasses therefrom, e.g., at least once the pellets have melted. The
vacuum pressure of less than or equal to about 125 mbar absolute
can be applied to the melt. The melt can then be extruded through a
die. From the die the extrudate may be directed through rollers to
produce the desired film (e.g., a substantially uniformly thick
film, such as a film having a thickness of 25 micrometers to about
750 micrometers, and cooled, actively or passively. The resultant
film possesses improved flame retardancy. For example, the film has
a reduced total flame out time (TFOT) or average total flame out
time (ATFOT) as compared to a film processed in the same fashion
without the sulfonate salt, and/or a film of the same composition
(neither with sulfonate salt) processed at a pressure of greater
than or equal to about 125 mbar absolute. The composition and the
processing can reduce the average total flame out time to less than
or equal to about 10 seconds (s), with less than or equal to about
5 seconds possible, compared to a film that was not vacuum
processed and/or does not comprise the sulfonate salt. An average
flame out time of less than or equal to 10 seconds per specimen,
and a total flame out time of less than or equal to 50 seconds is
needed to achieve a UL-94 VTM-0 rating.
[0040] In some applications the clarity of the flame retardant film
is important. There are two important components of transparency;
namely the light transmitted through the film: percent transmission
(% T) and the scattering of light by the film: percent haze (% H).
Films with high % T and low % H have better clarity. In some
instances the flame retardant film can have a transmission of
greater than or equal to about 50% and a haze of less than or equal
to about 10% (both determined in accordance with ASTM D1003;
"Standard Test Method for Haze and Transmittance of Transparent
Plastics"). In other instances %T of greater than or equal to about
75% and percent haze of less than or equal to about 5% is desired.
More specifically use of a perfluoro butyl sulfonate salt, for
example potassium perfluorobutyl sulfonate, can result in higher
clarity and lower haze than other salts.
[0041] Referring to FIG. 1, the total flame out time (in seconds
(s)) versus thickness (in micrometers (.mu.m)) and versus vacuum
pressure (in mbars absolute) are graphically illustrated for
polyetherimide films that do not contain sulfonate salt. In the
graph for the total flame out time versus thickness, each thickness
point is an average of the results obtained at pressures of 85
mbars absolute, 125 mbars absolute, 150 mbars absolute, and 250
mbars absolute. In the graph for the total flame out time versus
vacuum pressure, each pressure point is an average of the results
obtained at thicknesses of 50 micrometers, 75 micrometers, 100
micrometers, 125 micrometers, 200 micrometers, and 250
micrometers.
[0042] As is illustrated in FIG. 1, it was unexpectedly discovered
that the pressure employed during the processing of a thermoplastic
resin in the formation of a film affects the flame retardancy
thereof. By applying a pressure of less than or equal to about 125
mbars absolute, a UL-94 rating of VTM-0 could be attained in the
polyetherimide film with no sulfonate salt. For example, a vacuum
of about 85 mbars to about 125 mbars can be employed. In this
process, the resin pellets would be melt processed in an extruder,
or the like, e.g., using a dry vacuum. Once melted, the melt would
be subjected to a vacuum pressure of less than or equal to about
125 mbars absolute (e.g., about 110 mbars absolute to about 125
mbars absolute), typically for a short period of time (usually less
than or equal to about a minute), and then extruded through the
desired die and cooled. Use of the proper shaped die, the correct
melt temperature, and the proper cooling roll temperature, results
in a film of uniform thickness across its length, as well as a film
which has low stress and uniform properties. In one embodiment the
resultant film will not change shape excessively (i.e., it will be
used substantially as produced) during subsequent operations to
incorporate the film into a device. For instance, during
metallization of the film and processing of the metallized film to
make an electrical circuit.
[0043] Referring to FIG. 2, the maximum afterflame time (in
seconds) versus thickness (in micrometers (.mu.m)) and versus
pressure (in millibars (mbars) absolute) are graphically
illustrated for polyetherimide films that do not contain sulfonate
salt. Each point on this graph is the highest individual flame out
time value seen after two applications of flame to the five samples
tested at various thicknesses.
[0044] FIG. 3 illustrates the affects of pressure (namely a vacuum
of less than or equal to (.ltoreq.) 125 mbars absolute; and greater
than or equal to (.gtoreq.) 250 mbars absolute) on a PEI film, and
the effect of the addition of perfluoroalkyl sulfonate to the PEI
film. As can be see from the graph, the sulfonate salt containing
film consistently met the UL-94 rating of VTM-0 (TAFT less than 50
seconds) across various thicknesses independent of vacuum (line
denoted by open squares). Without the sulfonate salt the TAFT of
PEI film increases with increasing thickness (see the two lines
indicated by solid circles and solid triangles).
[0045] FIG. 3 illustrates that the use of the thermoplastic resin
film without sulfonate salt, at thicknesses exceeding 75
micrometers and having been processed with a vacuum pressure of
less than or equal to about 125 mbars absolute can reduce the total
flame out time of the film by greater than or equal to about 50
seconds, with greater than or equal to about 75 seconds possible,
versus a PEI film having the same thickness and no sulfonate salt
and with a vacuum of 250-350 mbars absolute; particularly at film
thicknesses of greater than 100 micrometers.
[0046] FIG. 3 further illustrates that the use of film comprising
sulfonate salt can reduce the total flame out time of the film by
greater than or equal to about 70 seconds, with greater than or
equal to about 100 seconds possible, and greater than or equal to
about 150 seconds attainable, versus a PEI film having the same
thickness and no sulfonate salt; wherein both films are processed
at pressures of greater than or equal to about 250 mbars absolute.
This effect is particularly evident at film thicknesses of greater
than 75 micrometers. At thicknesses of less than or equal to about
75 micrometers, the use of resin film comprising sulfonate salt can
reduce the total flame out time of the film by greater than or
equal to about 10 seconds (i.e., by greater than or equal to about
20%), with greater than or equal to about 25 seconds (i.e., by
greater than or equal to about 50%) possible, versus a resin film
having the same thickness and no sulfonate salt and with a vacuum
pressure of 250 to 350 mbars absolute.
[0047] Thus a film formed from resin, (e.g., polyimides,
polysulfones, and copolymers and mixtures comprising at least one
of these resins), with sulfonate salt and/or the use of a vacuum of
less than or equal to about 125 mbar during the formation process
(preferably melt process), reduces the total flame out time of the
resultant film as compared to a same composition film without
sulfonate salt (and having the same dimensions) and using a vacuum
of greater than or equal to 250 mbars absolute. The use of the
sulfonate salt enables the production of a film having a thickness
of 25 micrometers to about 250 micrometers and more (with up to and
exceeding about 350 micrometers believed possible) that meets UL-94
rating of VTM-0. Further reduction of the afterflame time can be
attained with the use of a vacuum of less than or equal to about
125 mbars absolute during the melt processing, alone or in
combination with the use of the sulfonate salt.
[0048] The unexpected effect of the pressure control, i.e., the use
of a vacuum of less than or equal to about 125 mbars absolute (and
especially about 100 mbars absolute to about 125 mbars absolute),
during the melt processing is believed to have applicability to
other thermoplastic resins such that, films produced with those
resins, using a vacuum of less than or equal to about 125 mbars
absolute (and especially about 100 mbars absolute to about 125
mbars absolute), will result in a reduced afterflame time for the
resultant film versus a film of the same composition produced using
a vacuum pressure of 250 to 350 mbars absolute. In other words, the
vacuum pressure used during the melt processing in the formation of
a film can be maintained at a pressure capable of reducing the
total flame out time versus a film of the same thermoplastic
composition processed at a vacuum pressure of greater than or equal
to 250 mbars absolute.
[0049] The films produced herein can be used for numerous
applications. Exemplary uses include insulation (e.g., cable
insulation) and wire wrapping, construction of motors, electronic
circuits (especially flexible circuits, transformers, capacitors,
coils, switches, separation membranes, computers, electronic and
communication devices, telephones, headphones, speakers, recording
and/or play back devices, lighting devices, printers, compressors
and similar devices), and the like. Optionally, the film can be
metallized or partially metallized, as well as coated with other
types of coatings designed to enhance physical, mechanical, and/or
aesthetic properties, e.g., to improve scratch resistance, surface
lubricity, aesthetics, brand identification, structural integrity,
and the like. For example, the films can also be coated with
printing inks, conductive inks, and similar other materials.
Metallization of the flame retardant film, for example, can be done
by sputtering, metal vapor deposition, ion plating, arc vapor
deposition, electroless plating, vacuum deposition, electroplating,
and/or other methods. Additionally, the films can be employed in
individual sheets or can be layered, folded, twisted or laminated
together to form more complex structures.
[0050] In one embodiment, the thermoplastic film can comprise:
greater than or equal to about 95 wt % resin selected from the
group consisting of polyimides, polyetherimidesulfones, polyimide
copolymers, polysulfones, polysulfone copolymers, and mixtures
comprising at least one of these resins, and about 0.001 wt % to
about 5.0 wt % sulfonate salt, (preferably with a thickness of
about 50 micrometers to about 350 micrometers), and a UL-94 rating
of VTM-0. Optionally, this film can have a transparency of greater
than or equal to about 50% as measured by ASTM D1003, or more
specifically, greater than or equal to about 75%, even more
specifically greater than or equal to about 80%, and even more
specifically greater than or equal to about 85%. A haze of less
than or equal to about 10% as measured by ASTM D1003 can also be
attained, or, more specifically, less than or equal to about 5%.
Optionally the film can have a T.sub.g of about 180.degree. C. to
about 350.degree. C. as measured by ASTM D3418 using differential
scanning calorimetry (DSC). This film also can have less than or
equal to about 2,500 ppm bromine and/or less than or equal to about
2,500 ppm chlorine, as well as a fluoropolymer in an amount of
about 0.01 wt % to about 2.0 wt %. The film can comprise about 0.01
wt % to about 1.0 wt % of the sulfonate salt, or more specifically
about 0.025 wt % to about 0.075 wt % sulfonate salt. Optionally,
the resin comprises polyetherimide, polyethersulfone, polysulfones,
polyethersulfone, polyphenylene ether sulfones and copolymers and
combinations comprising at least one of the foregoing resins.
EXAMPLES
[0051] Blends of polyetherimide (PEI) resin were prepared on a
vacuum vented single screw extruder using 0.1, 0.2, 0.3, 0.4, and
0.5 wt % of a potassium perfluorobutyl sulfonate salts (KPFBS),
based upon the total weight of the PEI blend. The extruder was set
at 300-360.degree. C. and run at about 80 revolutions per minute
(rpm) using vacuum venting. The resultant blend was pelletized,
dried, and extruded into clear films of 50, 100, 150, and 200
micrometers (.mu.m) thickness. The PEI resin had a weight average
molecular weight of about 38,000 g/mole. T.sub.g was measured by
differential scanning calorimetry (DSC) on the second scan.
[0052] The films were burned as described in Underwriters Lab (UL)
Test Method 94 VTM (UL-94 VTM). Films were tested both in the
machine direction (MD) and transverse to the machine direction
(TD). The UL-94 VTM tests a film of 200 millimeters (mm) by 50 mm
wrapped around a 12.7 mm diameter mandrel. Samples were conditioned
at 23.degree. C. and 50% relative humidity for at least 48 hrs, as
per the UL-94 test method.
[0053] Table 1 reports the total flame out time for the samples
with and without the KPFBS salt (for films tested transverse to the
direction of extrusion). Films of 50, 100, 150, and 200 micrometers
(.mu.m) were tested. There are two aspects of the UL-94 measurement
of flammability discussed here. The total flame out time (TFOT)
(also know as total after flame time (TAFT)) is the sum of the
time, in seconds (s) that all five sample remained ignited after
two separate applications of a flame as described in UL-94 VTM
test. The average total flameout time (ATFOT) is the TFOT divided
by the number of samples. The ATFOT is a per specimen value. The
TFOT or TAFT is an aggregate value of all samples tested. In either
case shorter time periods indicate better flame resistance, i.e.,
the flame went out faster. The tables below list average total
flame out time (ATFOT). FIGS. 1 and 3 report the TAFT for 5 samples
after two application of flame.
[0054] High T.sub.g (greater than or equal to 180.degree. C.) was
retained in all samples. T.sub.g was measured by DSC on the second
scan using a heating rate of 20.degree. C./min. TABLE-US-00001
TABLE 1 Example A 1 2 3 PEI (wt %) 100.0 99.9 99.8 99.5 KPFBS (wt
%) 0 0.1 0.2 0.5 T.sub.g.degree. C. 221.8 217.4 219.3 217.4 ATFOT
50 .mu.m (s) 9.1 3.6 3.7 1.3 ATFOT 100 .mu.m (s) 8.5 8.1 4.4 3.4
ATFOT 150 .mu.m (s) 8.8 8.0 7.3 2.6 ATFOT 200 .mu.m (s) 15.8 3.0
2.3 1.9 PEI films tested in the Transverse Direction (TD)
[0055] In Table 1, Control Example A shows longer average flame out
time, particularly at the thicker films than do the sulfonate salt
containing resins, Examples 1, 2, and 3, with the trend being to
shorter total flame out time with higher sulfonate salt content.
For the Control, ATFOT ranged from 8.5 seconds to 15.8 seconds over
thicknesses of 50 .mu.m to 200 .mu.m, while the samples with the
sulfonate salt maintained ATFOT of less than or equal to about 8.1
seconds throughout the entire test, with many samples having ATFOT
of less than or equal to about 4.0 seconds.
[0056] Table 2 shows the same compositions, having the films of the
same thickness, 50 micrometers to 200 micrometers, but tested in
the machine direction (MD). In most cases, the KPFBS salt was
effective in lowering the total flame out time compared to the PEI
film with no sulfonate salt added (Example B). TABLE-US-00002 TABLE
2 Example B 4 5 6 7 8 PEI (wt %) 100.0 99.9 99.8 99.7 99.6 99.5
KPFBS (wt %) 0 0.1 0.2 0.3 0.4 0.5 ATFOT 50 .mu.m (s) 3.8 3.7 2.2
2.4 2.0 2.1 ATFOT 100 .mu.m (s) 5.1 4.3 6.9 2.4 2.0 2.0 ATFOT 150
.mu.m (s) 3.5 7.8 3.0 2.4 1.4 2.0 ATFOT 200 .mu.m (s) 4.9 2.9 2.5
1.8 1.6 1.9 PEI films tested in the Machine Direction (MD)
[0057] Again higher levels of salt were more effective than lower
levels in producing films having faster extinguishing times.
Additionally, the ATFOT was reduced to less than or equal to 3
seconds for all (PEIS) resin made by polymerization of bisphenol A
dianhydride (BPA-DA) with diamino diphenyl sulfone. The polymer had
a weight average molecular weight (Mw tested salt concentrations in
films 200 .mu.m thick).
[0058] For Examples C and 9-11, film extrusion was done using dried
polyetherimide sulfone resin on a 1.5 inch unvented single screw
extruder, 24:1 length to diameter (L/D) at 320-340.degree. C. at
about 35 rpm. Table 3 shows the effectiveness of the sulfonate salt
in a polyetherimide sulfone) of about 34,000 g/mole. Samples were
tested in the machine direction (MD). Use of the KPFBS salt reduced
the total average flame out time as measured by UL-94 VTM method in
50 micrometer and 150 micrometer films, while low haze and high
transmission were retained in films with the added sulfonate salt.
Percent haze and percent transmission were measured on films as per
ASTM D1003 on a Gardner XL-835 colorimeter. TABLE-US-00003 TABLE 3
Example C 9 10 11 12 PEIS (wt %) 100.0 99.9 99.85 99.8 99.7 KPFBS
(wt %) 0 0.1 0.15 0.2 0.3 Haze 50 .mu.m (%) 0.8 0.8 0.8 0.4 0.4
Haze 150 .mu.m (%) 7.5 5.1 4.4 3.7 6.7 Transmission 50 .mu.m (%)
87.2 87.3 87.6 87.4 86.9 Transmission 150 .mu.m (%) 86.2 85.9 86.3
86.6 86.4 ATFOT 50 .mu.m (s) 6.1 5.2 5.4 2.5 3.7 ATFOT 150 .mu.m
(s) 2.2 0.2 2.2 1.8 1.8 PEIS films tested in the Machine Direction
(MD)
[0059] For Examples D and 13-15, film extrusion was done using
dried PEIS resin on a 1.5 inch unvented single screw extruder, 24:1
L/D at 340-370.degree. C. at about 35 rpm. Table 4 shows the same
polyetherimide sulfone samples as Table 3 tested in the transverse
direction (TD). Addition of the KPFBS salt reduced flame out time.
Compared to the control (without sulfonate salt), 50 .mu.m samples
with sulfonate salt, tested in the transverse direction, had a haze
of less than or equal to 5%, a transmission of greater than or
equal to 85% (a change in transmission of less than or equal to
about 1%, more specifically, less than or equal to about 0.5%), and
a ATFOT of less than or equal to 5 seconds. TABLE-US-00004 TABLE 4
Example D 13 14 15 PEIS wt % 100.0 99.9 99.8 99.7 KPFBS wt % 0 0.1
0.2 0.3 Haze 50 .mu.m (%) 0.8 0.8 0.4 0.4 Transmission 50 .mu.m (%)
87.2 87.3 87.4 86.9 ATFOT 50 .mu.m (s) 6.8 3.8 2.0 1.2 PEIS films
tested in the Transverse Direction (TD)
[0060] Table 5 shows the effectiveness of the KPFBS salts in
improving UL-94 VTM performance in a polyethersulfone (PES) resin
blend. ULTRASON E polymer from BASF Co. was extruded with 0.5 wt %
KPFBS salt, based on the total weight of the PES blend. Samples
were tested in the machine direction (MD). The resultant pellets
were dried and extruded into films of 50 micrometers and 150
micrometers. As can be seen in Control Example E and in Example 16
the sulfonate salt containing blend has reduced average total flame
out time while maintaining high T.sub.g, low haze, and high
transmission.
[0061] In other words, with the use of the sulfonate salt, total
flame out times for films tested in the machine direction, having a
thickness of about 50 .mu.m to about 200.mu.m, ATFOT is less than
or equal to 5.5, more specifically, less than or equal to 5.0.
Additionally, a transmission of greater than or equal to about 80%,
specifically, greater than or equal to about 85% was retained
(i.e., a change in transmission from a resin without the salt to a
resin with the salt was less than or equal to about 0.1%), and a
haze of less than or equal to about 5% was retained, more
specifically, less than or equal to about 2%, and even less than or
equal to about 1%. TABLE-US-00005 TABLE 5 Example E 16 PES (wt %)
100.0 99.5 KPFBS (wt %) 0 0.5 T.sub.g.degree. C. 226.3 225.9 Haze
50 .mu.m (%) 0.7 0.9 Haze 150 .mu.m (%) 1.8 1.1 Transmission 50
.mu.m (%) 88.7 88.8 Transmission 150 .mu.m (%) 87.8 87.9 ATFOT 50
.mu.m (s) 9.4 2.4 ATFOT 150 .mu.m (s) 6.7 5.0 PES films tested in
the Machine Direction (MD)
[0062] For Examples F and 17, film extrusion was done using dried
polyether sulfone resin on a 1.5 inch unvented single screw
extruder, 24:1 L/D at 320-340.degree. C. at about 35 rpm. Table 6
shows the same polyethersulfone samples as in Table 5 tested in the
transverse direction (TD). Addition of the KPFBS salt reduced flame
out time. For films with the salt, the ATFOT was less than or equal
to 5.0 seconds, for films having thicknesses up to about 200 .mu.m.
TABLE-US-00006 TABLE 6 PES TD VTM Total Flame Out Times Example F
17 PES (wt %) 100.0 99.5 KPFBS (wt %) 0 0.5 T.sub.g.degree. C.
226.3 225.9 Haze 50 .mu.m (%) 0.7 0.9 Haze 150 .mu.m (%) 1.8 1.1
Transmission 50 .mu.m (%) 88.7 88.8 Transmission 150 .mu.m (%) 87.8
87.9 ATFOT 50 .mu.m (s) 7.8 4.0 ATFOT 150 .mu.m (s) 7.8 4.0 PES
films tested in the Transverse Direction (TD)
[0063] The incorporation of sulfonate salt(s) in to a thermoplastic
resin, namely PEI, PEIS, and PES, has unexpectedly reduced average
total flame out time of the resin versus these thermoplastic resins
without the sulfonate salt, while retaining transmission and haze
properties, as well as retaining a T.sub.g of greater than or equal
to 180.degree. C., more specifically, T.sub.g of greater than or
equal to about 200.degree. C.
[0064] Flame retardancy was achieved without impairing melt
stability and melt processability while simultaneously retaining
clarity, high % T, low % H and high heat resistance (T.sub.g)
clarity.
[0065] While the invention has been described with reference to an
exemplary embodiment, it will be understood by those skilled in the
art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope of the appended
claims.
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