Note: Descriptions are shown in the official language in which they were submitted.
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08CT0 4 97 3
AMORPHOUS POLYAMIDE COMP05ITIONS CONTAINING A
CARBON BLACK COMPOUND EXHIBITING IMPRO~ED MELT FLOW
Deborah L. Mendel
G Fred Willard
BACKGROUND OF THE INVENTIQN
Field of th~ InventiQn
The present invention relates to amorphous
polyamides and reinforced articles made therefrom,
and, more particularly, relates to compositions
con~aining amorphous polyamides and a carbon black
5 compound and reinforced artioles made from such
compositions.
DESCRIPTION QF RELAIED ~RI
Carbon black is a known additive to polymers.
Specifically, carbon black has been added as a
colorant and filler in variou~ resin compositions. In
addition, carbon black has been used to improYe the
conductive properties of some polymer compositions.
Generally, the addition of carbon black increases the
viscosity o~ the polymeric composition; see for
example K. Lakdawala and R. Salevey, "Rheology of
Polymers Containing Carbon Black," PQ1Vm. Enq~ Sci..
27(14~, p. 1035 (1987). These inc~eases in viscosi~y
upon addit~on of carbon black are also noted in Datta,
U.S. Patent 4,299,736. Datta discloses that the
20 addition of carbon black a~ 15 weigh~ percen~
increases the melt viscosity of the polyvinyl chloride
composition, but this increase in viscosity is reduced
when carbon black compounds treated wi~h a fatty acid
chloride are present in the poly~inyl chloride
compssition. In Datta, the melt viscosi~y of the
compositions set forth in the examples containing fatty
acid chloride treated carbon black compound is lower
than the melt viscosity of a comparison composition
containing untreated carbon black cvmpounds, but shows
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08CT04973
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little or no improvement over the melt viscosities of
the pure polyvinyl chloride resin.
Lakdawala d;scloses that the addition of a carbon
black compound to a high molecular weight polystyrene
5 resulted in a composition that exhibited a viscosity
lower th~n that of the neat polymer at high shear
rates and at carbon loading levels of 5 and 10 weight
percent based on the total weight of the composition,
but further discloses that reduced viscosities were
not observed for several other polymers, specifically,
a low molecular weight polystyrene and a poly~butyl
methacrylate).
In a similar study Lakdawala (K. Lakdawala and R.
Salovey, "Rheology of Copolymers Containing Carbon
Black," Polym. Enq~ ~ci.. 27~14) p. 1043 (1987) at p.
1044, 1045) indica~ed that the addition of certain
carbon black compounds to certain copolymers of
styrene and butyl methacryl ate exhibited lower
viscosities than that of the neat copolymers under
par~icular high shear rates and carbon loading levels.
Lakadawala's specific disclosures of impro~ed melt
viscosities appear to be limited to examples of weight
loadings of 5 percent and in some cases 10 percent and
20 percent.
Whlle the art teaches that the addition of 5, 10
and 20 weight percent of certain carbon black
compounds under specifie conditions to a high
molecular weight polystyren~ and to two types of
copolymers of styrene and butyl methacrylate results
in reduced viscosities the art also illustrates a
number of conditions and compositions for which this
reduced viseosi~y effect was no~ observe~ upon the
addition of a carbon black ccmpound ~o ~arious
polymers and copolymers. These references do not show
how to reduce the mel~ Yiscosi~y of amorphous
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08CT04973
polyamides and more speci~ically do not suggest that
small amounts of carbon black compounds should be
added to amorphous polyamides to reduoe ~he viscosity
thereof. Additionally, none of these references
indicate that it is desirous to add amounts smaller
than 5 weight percent to amor~hous polyamides to
obtain reduced viscosities over the viscosities of the
neat amorphous polyamide resin.
Padron (Al~onso J.C. Padron, "Influence of
Additives on Some Physical Properties of High Density
Polyethylene-I-Commercial Antioxidants", E~r. PQ1 Vm .
J. vol. 23, No. 9 p. 723 (1987) at p. 725.) discloses
tha~ the addition of 1 percent by weight of a carbon
black compound to a high density polyethylene results
lS i n a composition that exhibits a melt flow index
greater than the melt flow index of nea~ high densi~y
polyethylene. Figure 5 of the Padron article
indica~es that this increased melt flow index is no~
achieYed at concentrations of carbon black
substantially above or below 1 weight percent. Padron
does not teach or suggest that the addition of small
amounts of a carbon black compound amorphous
polyamides will result in improved melt flow
properties thereof, and more specifically does not
teach that the addition of small amounts o~ carbon
black compound to amorphous polyamides will result in
improved flow properti~s at low shear rates.
Amorphous polyamides, such as Nylon 6IT, are
known. However, many amorphous polyamides, especially
highly aromatic amorphous polyamides, exhibit higher
melt Yiscosities ~han are desired for processiny
thereof and for producing reinforced artioles
.
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08CT04973
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therefrom. Therefore, a need exists ~or amorphous
polyamide compositions having reduoed melt
viscosities.
A~cordingly, one objective of the present
invention is to provide amorphous polyamide
compositions having reduced melt viscosities.
SU ARY OF THE INV~NTIQ~
The present i nventi on provi des amorphous
polyamide compositions having reduced melt
viscosities. The compositions contain ~i) an
amorphous polyamide resin and (ii) a oarbon black
compound. The carbon black compound is preferably
present in the composition at a level of 0.05 percent
to 2.0 percent by weight based on the total combined
15 weight of the amorphous polyamide resin ànd carbon
black compound. The carbon black compound is
primari ly made up of carbon black particles having
particle diameters of preferably less than 320
millimicrons. This composition is useful as an
injection molding composition and as a resin matrix
for the production of fiber reinforced composites.
~ETAILED DESCRIPTI~N OF T~E~ ENTION
This i nYenti on relates to amorphous p31yamide
composit~ons comprising (i) a carbon black compound at
Z5 a level of from 0.05 percent to 2.0 percent by weight
based on the total combined weight of the amorphous
polyamide resin and the carbon black compound. The
present invention also involves fiber reintorced
articles made from the amorphous polyamide oomposition
and reinforcing fibers.
Amorphous polyamides are noncrystalline ngsins
which do not exhibit a distinct melting poinkO
Examples of amorphous polyamides are Nylon 6,I,T and
polyamides derived from ~oluenediamine and a
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OBCT04973
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dicarboxylic acid; Nylon 6,I; polymers derived ~rom
meta-xylenediamine, and isophthalic acid, polyamides
derived from bis(para-aminocyclohexyl)methane and
disarboxylic acids; polyamides deri ved from
2,2,3-trimethylhexamethylene diamine and terephthalic
acid; and polyamides derived from isophthalio acid and
bis(4-amino-3-methylcyslohexyl)methane. The preferred
amorphous polyamide for the present invention is
derived from toluenediamine and either an isophthalic
acid, a mixture of isophthalic acid and terephthalic
acid, or a mixture of isophthalic acid and aliphatic
dicarboxylic acid, and generally exhibits high melt
viscosities which makes it desirable to add the carbon
black compound of the resent invention to reduce the
15 melt viscosity of the polyamide composition.
Polyamides may be obtained either by reacting a
diamine with a dicarboxylic acid or by reacting a
diamine with a diester of the dicarboxylic acid.
The amorphous polyamide of the composition is
~o prefera~ly present at a level of from 98 percent to
99.95 percent by weight based on the combined total
weight of the amorphous polyamide and the carbon black
compound, more preferably is present at a level of
from 99 ts 99.8 percent by wei~ht thereof, and most
preferably is present at a level of about 99.5 percent
by weight thereof.
Carbon black compounds are finely divided
carbonaceous pigments which can be produced by the
incomplete combustion or thermal cracking of
hydrocarbons. Suitable types of carbon black
compounds for the present invention inelude furnaee
black, thermal black and channel black. The carbon
black compound for the present invention is made up of
carbon black particles having diameters of at most 320
millimicrons and preferably particle diameters of from
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5 millimicrons to 320 millimicrons, more preferably
particle diameters of from 10 millimicrons to 150
millimicrons, most preferably with particle diameters
of about 17 millimicrons. The preferred carbon black
S compound for the present invention is a furnace carbon
black with a particle diameter of 17 millimicrons,
density of 15 pounds per cubic foot, surface area of
210 square meters per gram, an oil absorption rate of
75 cubic centimeters per 100 grams, and is available
o from Cabot Corporation under the commercial name
Monarch 800. The ~arbon black compound is preferably
present at a level of from 0.05 percen~ to 2.0 percent
by weight based on the total weight of the amorphous
polyamide resin and carbon black compound, more
preferably present at a level of from 0.2 percent to
l.0 percent by weight thereof, and most preferably
present at about 0.5 percent by weight thereof.
The compositions comprising an amorphous
polyamide resin and a small amount of carbon black
20 compound exhibit reduced viscosities and increased
melt flows compared tQ ~hat of the pure amorphous
polyamide resin. The amorphous polyamide compositions
having increased melt flow are ~i) easier to process,
(ii) useful for producing injection molded articles,
and (i~) useful for producing glass ~iber reinforced
amorphous polyamide composites.
The present invention is suitable for forming a
fiber-reinforced composition comprising an amorphous
polyamide, a carbon black compound and fiber
30 reinforcements. Suitable reinforcing fibers for the
present i nventi on i ncl ude 9l ass fi bers, mi neral
~ibers, long glass fiber ma~, carbon fibers and metal
fibers. The reduce~ melt viseosi~ies of ~he
compositions make it easier ~o produce fiber
35 reinforced composi~e ar~icles having long fiber mats
th~rei n.
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0 8CT0 4 9 7 .
The present invention is particularly useful for
forming fiber reinforced composites comprising an
amorphous polyamide resin, a carbon black compound and
a long glass fiber mat. The fiber mat is preferably
5 present at a level of from 20 to 60 weight percent
based on the combined total weight of the amorphous
polyamide, carbon black compound and long glass fiber
mat. The pref~rred fiber mat for the present
invention is a glass fiber mat of woven or non-woven
gl~ss fiber strands or glass fiber filaments. The
glass fiber mat is a porous, light weight material and
may have a thickness of from 10 to 150 mils and a
weight of from 0.1 to 5 ounces per square foot. The
lower melt viscosity of the carbon black containing
amorphous polyamide composition containing carbon
black makes it easier to produce long fiber mat
reinforced amorphous polyamide composites~ Reduced
melt viscosi~y and increased melt flow are desired
characteristics for the amorphous polyamide
20 compositions used to make the composites since high
levels of flow of the amorphous polyamide compositions
between and among the fibers in the glass fiber mat is
necessary to completely fill the material and produce
fiber reinforced articles having high levels of
2s strength.
The following examples are presented by way of
illustration of the present invention and not by way
of limitation.
.
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DES~RIPTIQN OF EX~MP~ES IN TABLE 1
An amorphous polyamide WdS derived from the
reaction products of a diamine and a dicarboxylic
acid. The diamine was a mixture of 70 mole persent of
toluenediamine and 30 mole percent of
hexamethylenediamine based on the total moles of
diamine. The diaryl ester of the dicarboxylic acid
was employed. The diaryl ester was a mixture of 75
lC mole percent of diphenyl isoph~halate and 25 mole
percent of diphenyl terephthalate based on the total
moles of diarylester of dicarboxylic aeid.
The sarbon black compound used was a furnace
black grade having surface area of 25 square meters
per gram, an oil absorption rate of 72 cubic
centimeters per 100 grams, particle diameters of 75
millimicrons and a d~nsity of 18 pounds per cubic
foot. The carbon black compound was obtained from
Cabot Corporation under the commercial name of Monarch
120.
In Examples 1 ~o 5 the amorphous polyamide was
compounded with various loadings of the carbon black
compound of from 0.1 to 2.0 percent by weight based on
the combined total weight of the amorphous polyamide
25 . and carbon black compound. The melt index data are
summarized in Table 1. A melt index measurement was
attempted for a loading of 5 weight percen~ carbon
black oompound but the mix~ure was too VisGous to stir
blend well. The melt index of resin containing no
carbon black is set forth in compara~ive Example A.
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OBCT0~973
g
TABLE 1
Melt Index Data for Carbon Black Compound
Loadings in an Amorphous Polyanide
aLoading Level bMelt Index*
(w~iqht p~ent) (~ram Der lQ minla~es)
A. 0 0.190
0.1 1.518
2 0.2 1.885
3 0.5 2.~85
4 1.~ 1.441
2.0 0.~60 .
* at 315C and 1200 gram load after a 6 minute
preheat.
a Weight percent~of the carbon black eompound added ~o
the amorphous polyamide based on the combined total
weight of the amorphous polyamide and the carbon
black compound.
b Conducted using a Tinius Olsen Extrusion Plastometer
where measurement is amount of material extruded in
ten minutes.
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08~T04973
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DES~RIPTION OF EXAMPLES IN TABLE 2
An amorphous polyamide was derived from the
reaction products of a diamine and a diester of a
5 d karboxylic acid. The diamine is a mixture of a 70
mole percent of toluenediamine and 30 mole percent of
hexamethylenediamine based on the total moles of the
diamine. The diester of the dicarboxylic acid is a
mixture of a 75 mole percent of diphenylisophthalate
and 25 mole percent of diphenylterephthalate based on
the to~al moles of dicarboxylic acid.
In Examples 6 to 12 the amorphous polyamide was
mixed with various types of carbon black compound.
ThP carbon black compound was added to maximize the
melt flow while maintaining other properties of the
mixture such as dynatup impact and tinting strength.
Table 2 gives the results of this study as well
as properties of the differen~ carbon black compounds
used. Fhe carbon black compound was present at a
ZO level of 0.1 percent by weight based on ~he combined
~otal weigh~ of the carbon black compound and the
amorphous polyamide. Most of the carbon black
compounds studied showed an improvement over the
control which was composed only of the amorphous
polyamide melt flow. Oontrary to the other carbon
black compounds tested, the carbon bl~ck compound of
Table 2, Example 11, which had a particle diameter of
320 millimicrons, showed a melt flow which was
essent~ally equivalent to the melt flow of the
control which had no carbon black added to ~he
amorphous polyamide.
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08cq~04973
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For examples 13 to 17 of Table 3 an amorphous
polyamide was derived from the reaction products of a
diamine and a diester of a dicarboxylic acid. The
di ami ne was a mi xture of 50 mole percent
5 meta-xylenediamine and 50 mole pereent
hexamethylenediamine based on the total moles of the
diamine. The diester of the dicarbo%ylic acid was
diphenylisophthala~e.
The amorphous polyamide was mixed with various
types of carbon black compound. Table 3 ~ives the
results of this study as well as properties of the
different carbon black compounds used. The carbon
black compound was present at a leYel of 0.1 percent
by weight based on the combined total weight of the
carbon black compound and the amorphous polyamide. In
all cases the carbon black compounds studied showed an
improvement over the control which was composed only
- of the amorphous polyamide melt flow. Control B had
no carbon black added to the amorphous polyamides.
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2~39136
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EX~PLE_l~
An amorphous polyamide was deriYed from the
reaction products of a diamine and a dicarboxylic
5 acid. The diamine was hexamethylene diamine. The
dicarboxylic acid was a mixture of 65 mole percent
isophthalic acid and 35 mole percent terephthalic acid
based on the total moles of the dicarboxylic acid.
This polyamide was commercially available as Selar PA
o ~DuPont). The polyamide was mixed with 0.1 percent of
a furnace carbon black compound which had a particle
diameter of 17 millimicrons~ density of 15 pounds per
cubic foot, surface area of 210 square meters per
gram, an oil absorption rate of 75 cubic centimeters
per lO0 grams, and was available from Ca~ot
Corporation under the commercial name Monarch 800.
The melt index at 265C and 1200 gram load after a 6
minute preheat was 67.5 grams/10 minutes ~or the
carbon blaek containing amorphous polyamide and 3.38
grams/10 minutes for the neat polyamide.
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08CT04973
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EX~MPL~ 19
An amorphous polyamide was derived from the
reaction products of a diamine and a dicarboxyli~
acid. The diamine was a mixture of bis(4-amino-3-
methylcyclohexyl)methane and Nylon 12. The
di carboxyl i c aci d was i sophthal i c aci d . Thi s pol yami de
was commercially a~ailable as Grilamid TR55 ~Emser
Werke). The polyamide was mixed with 0.1 percent of a
lQ furnace carbon black compound which had a particle
diameter of 17 millimicrons, density of 15 pounds per
cubic foot, surface area of 210 square meters per
gram, an oil absorption rate of 75 cubic centimeters
per 100 grams, and was available from Cabot
Corporation under the commercial name Monarch 800.
The melt index at 265C and 1200 gram load after a 6
minute preheat was 3.35 gramsllO minutes for the
carbon black containing amorphous polyamide and 1.15
gramsllO minutes for the neat palyamide.
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