Note: Descriptions are shown in the official language in which they were submitted.
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TITLE
TRANSLUCENT POLYAMIDE BLENDS
This application claims benefit of priority from Provisional Application
No. G0/238,973, filed October 10, 2p00.
Field ofthe Invention
The present invention relates to polyamide blends. More specifically, it
relates to polyamide resins that are translucent while retaining excellent
mechanical and thermal properties.
Back~raund of the Invention
It is known that a characteristic property of many unFilled amorphous
materials is transparence. Crystalline and semi-crystalline materials are, on
the
other hand, often opaque due to the fact that the crystalline domains in these
materials scatter incident light.
It is known that polyamides, also known broadly as nylons, are excellent in
toughness, heat resistance, oil resistance, and processability. Examples of
such
polyamides include aliphatic polyamides such as those commonly denoted nylon
6, nylon 6,G, nylon 6,10, nylon 12, and the like. These polyamides are
generally
semi-crystalline. Such semi-crystalline polyamides are widely used for
engineering plastics, fibers, etc., owing to the above mentioned excellent
properties. As engineering plastics, they are widely used in various
applications,
such as electric and electronic parts and accessories for automobiles.
However, a
drawback of the above polyamides for many applications is that they are often
opaque due to the presence in the polymers of spherulite crystals. The
spherulite
crystals are sufficiently large to interfere with and scatter visible light.
It is a common practice to use reinforcing tillers in polyamide formulations
to increase the tensile and flexural strengths of articles produced therefrom.
US
Patent No. 5,053,447 discloses a polyamide-based thermoplastic formulation
having: a) at least 50 weight percent, based on the total weight ofthe
formulation,
unreinforced nylon selected from nylon 6,6, nylon 6, or mixtures thereof; b)
about
5-50 weight percent fillers; and c) a sufFcient amount of decabromodiphenyl
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ethane to provide a melt index value that is higher than the melt index value
ofthe
nylon alone. The fillers used are glass fibers.
Glass fibers used as fillers are known to distort or interfere with the
passage of light in plastics. US Patents Nos. 5,149,897 and 4,133,287 disclose
the
problem that when glass fibers are added to nylon as reinforcing or
strengthening
agents, they can interfere with the optical properties of the materials.
It is known that certain unfilled amorphous copolyamides can be molded
to produce transparent articles. US Patent No. 4,404,317 describes blends of
at
least one amorphous copolyamide and at least one semi-crystalline polyamide in
which the amorphous copolyamide is the predominant component. The present
invention builds upon this work by describing how translucent materials can be
made by blending semi-crystalline materials with or without an amorphous
component in the presence of a catalyst and glass filler that serve to enhance
both
the translucency and physical properties of the resulting materials.
US Patent No. 6,022,613 describes compositions having a high degree of
transparency that contain blends of select polyamide homopolymers or
copolymers having balanced amino and acid terminal groups with further select
polyamide homopolymers or copolymers having an excess of terminal amino
groups. These requirements, however, present a major limitation regarding the
range of polyamides that can be used in preparing the blends.
There is a need for novel polyamide compositions that are translucent, and
that possess the strength, toughness, heat resistance, chemical resistance,
etc. that
are known to the art as characteristic of non-amorphous polyamides.
Summary of the Invention
An optically translucent polyamide composition is disclosed herein,
comprising:
a) 59 to 96.99 weight percent of a miscible blend of at least two
polyamides and wherein at least one of these polyamides is a
semicrystalline polyamide;
b) 3 to 40 weight percent of a glass filler; and
c) 0.p1 to 1 weight percent of a catalyst containing phosphorus in an
oxidation state of +1, +2, or +3.
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Another aspect of the invention is an improved process for the preparation
of such compositions, comprising first providing the above-described miscible
blend, and adding thereto the glass filler and catalyst mentioned above to
form a
blend mixture. The blend mixture is melt-blended to form a homogeneous blend.
Further processing to shape the blend may include any of a variety of
techniques
as understood by those having skill in the art. These include without
limitation
injection molding, blow molding, extrusion, coextrusion, compression molding,
or
vacuum forming.
Shaped articles of the invention may include, again without intending to
limit the generality ofthe foregoing, bottles, sheets, films, packaging
materials,
pipes, rods, laminates, sacks, bags, molded goods, granules, or powders.
Detailed Description of the Invention
It is known that adding glass fibers to semi-crystalline polyamides
improves the stiffness of the materials. However, this improvement goes hand
in
hand with a strong impairment in impact resistance as well as diminished
optical
properties. The term 'optical properties' means the ability of the material in
question to transmit visible light. Materials can be 'transparent', in which
case
they will transmit visible light without significant scattering such that
items lying
beyond are completely visible. Materials can also be 'opaque', in which ease
visible light will be blocked and one cannot see through an object made from
those materials. In between are materials that transmit some visible light,
such
that items lying beyond can be seen, but perhaps not perfectly clearly or at a
distance. Such materials are referred to as 'translucent'. There are many
possible
applications for materials that are translucent, but not fully transparent.
For
example, it may be necessary that an item viewed through the material be only
a
short distance from the material or it may be desired that only items close to
the
material be visible. The degree of translucency a material can provide will
often
be a function ofthe thickness of an object made from that material.
The compositions described herein are resin compositions that not only have
excellent physical properties and processability, but are translucent. The
compositions have three components: (A) a melt miscible/compatible blond ofat
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least two polyamides, at least one of which is crystalline or semi-
crystalline; (B)
glass Fbers, glass beads or other fillers that could improve heat transfer;
and (C) a
catalyst.
Miscible blend (A) of~olyamides including synthesized semi-crystalline
block/random co~olyamides:
The first component (A) is a blend of at least two miscible thermoplastic
polyamides, at least one of which is a semi-crystalline polyamide. These
resins
can include semi-crystalline homopolymers, and block and random copolyamides.
A thermoplastic semi-crystalline polyamide has a distinct melting point with a
measurable heat of fusion, whereas an amorphous polyamide generally has
neither
a distinct melting point nor a measurable heat offusion. Normally, a polyamide
homopolymer, such as nylon 6,6, is a semi-crystalline polymer.
Semi-crystalline polyamides are well-known in the art and widely
available. They may be formed by condensation polymerization as well as
addition polymerization, as discussed in The Ejicl~clopedia of Pohnn~r Science
afrcl Ej~gineet~ing, 2nd >;dition, 1985, Wiley, Vol. 11, pages 318-360. The
polyamides generally have molecular weights over 10,000 and can be produced by
the condensation of equimolar amounts of a saturated aliphatic dicarboxylic
acid
containing from ~-12 carbon atoms and an aliphatic diamine containing 2-12
carbon atoms, in which the diamine can be employed, if desired, to provide an
excess of amine end groups over carboxylic acid end groups in the polyamide.
Alternatively, the diacid can be used to provide an excess of acid end groups.
Equally well, these polyamides may be made from acid-forming and amine-
forming derivatives of said acids and amines such as esters, acid chlorides,
amine
salts, etc. Representative aliphatic dicarboxylic acids used to make the
polyamides
include adipic acid, pimelic acid, azelaie acid, suberic acid, sebacic acid,
and
dodecanedioic acid, while representative aliphatic diamines include
hexamethylenediamine and octamethylenediamine. In addition, these polyamides
3o can also be prepared from the self condensation of a laetam.
By means of example, suitable polyamides for use in the miscible blend
making up component (A) include: polycaprolaetam (nylon 6), polynonanolactam
(nylon 9), polyundecaneolactam (nylon 1 1 ), polydodecanolactam (nylon 12),
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poly(tetramethylenediamine-co-adipic acid) (nylon 4,6), polyhexamethylene
azelaiamide (nylon 6,9), polyhexamethylene sebacamide (nylon 6,10),
polyhexamethylene isophthalamide (nylon 6,IP), polymetaxylylene adipamide
(nylon MXDG), the polyamide of n-dodccanedioie acid and
hexamethylenediamine (nylon 6,12), the polyamide ofdodecamethylenediamine
and n-dodecanedioic acid (nylon 12,12), as well as copolymers thereof.
Kepresentative copolymers are the polyamide of hexamethylene adipamide and
caprolactam (nylon 6,6/6), the polyamide of hexamethylene adipamide and
hexamethylene-isophthalamide (nylon 6,6/6IP), the polyamide of hexamethylene
1Q adipamide and hexamethylene-terephthalamide (nylon 6,616T), the polyamide
of
hexamethyleneterephthalamide and (2-methyl)pentamethyleneterephthalamide
(nylon 6T/DT), the polyamide of hexamethylene adipamide, hexamethylene
azelaicamide, and caprolactam (nylon 6,6/6,9/6), the polyamide of
hexamethylene
terephthalamide and hexamethylene decanediamide (nylon 6T/6,10), and the
polyamide of hexamethylene terephthalamide and hexamethylene
dodecanediamide (nylon 6T/6,12), as well as others which are not particularly
delineated here.
Suitable polyamide copolymers could also be synthesized by condensation
and ring opening polymerization, as will be understood by those skilled in the
art.
A copolymer will not necessarily be an amorphous material as many copolymers
have distinctive melting points. The definition of copolymer here is a polymer
synthesized by more than two kinds of monomer pair blocks (e.g., terephthalic
acid, isophthalic acid, hexamethylenediamine, 1,12-diaminodedecane,
caprolactam). The addition of mufti-monomer copolymers into polymer blends
could also effectively reduce the size of spherulites and even significantly
reduce
the degree of crystallization.
Suitable amorphous polyamides will be copolymers that can include, but
are not limited to, copolymers made from ingredients such as isophthalic acid,
terephthalic acid, hexamethylenediamine, bis(~a-aminocyclohexyl)methane, 1,4-
bis(aminomethyl)cyclohexane, or 1-amino-3-aminomethyl-3,5,5-
trimethylcyclohexane, as is understood by those skilled in the art.
It is critical that a blend be of at least two, but preferably more, miscible
and compatible nylons, thus facilifating the reduction of the spherulite sizes
in the
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crystalline regions of the semi-crystalline polymer components. Adding an
amorphous polyamide could also facilitate a reduction in spherulite size. With
optimally sized and dispersed phases and adequate interphase adhesion, the
compatible polyamides provide a blend morphology conducive to useful
S mechanical properties.
As discussed herein, by miscible blends, it is meant that the blends of two
or more melt compatible polyamides, at least one of which is semi-crystalline,
of
the present invention behave as a single homogeneous polyamide, exhibit a
single
T~, and give a single-phase composition in which the stratification ofthe
to polymeric components during or after processing is generally avoided. Since
immiscible blends are phase separated, they suffer from delamination at the
phase
boundaries because of the weak bonding between the phases. This leads to light
scattering, which negatively affects the optical properties of the molded
articles.
Since this miscibility is crucial for translucency, the selection of nylons
15 used for the blends will depend on their mutual compatibility. One way to
judge
the miscibility of two or more polyamides is by examining the appearance of
the
molten mixture, which should be transparent for compatible materials and
cloudy
for incompatible materials. For example, nylons G and 6,6 are fully miscible
and
form a transparent melt. On the other hand, nylons G,G and 12 are not miscible
20 and form a cloudy melt. A cloudy melt is one in which the material contains
inhomogeneous regions that scatter light to the point where objects behind the
melt are not fully and clearly visible at a distance,
The following are some examples of potential polymer blends. In
parentheses is the appearance of the molten mixture:
( 1 ) Nylon G and nylon 6,G (transparent melt)
(2) Nylon G,10 and nylon G,12 (transparent melt)
(3) Nylon G,12 and nylon G (cloudy melt)
(~1) Nylon G and nylon G,G, and nylon 12 (cloudy melt)
3o
If a molten polymer blend is not transparent, then that blend is not a good
candidate for a translucent nylon material.
G
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Preferred blends making up component (A) include: a blend of (i) nylon
G,G and (ii) nylon G; a blend of (i) nylon G,G, (ii) nylon G, and (iii) an
amorphous
nylon; and a blend of (i) nylon G,G and (ii) nylon G, and (iii) nylon GT/DT.
The blend (A) is preferably present in an amount of from G9.5 to 95.9
weight percent, and with a most preFerred range of 74.G to 95.3 weight
percent.
Glass fillers (B~
The glass fillers when used in the form of glass fibers or glass beads are
obtained from an inorganic glass composed of oxides, e.g., SiOZ, BZO~, A120~,
CaO, NazO, and K~O. Preferred amounts ofthese and other fillers are in the
range
of 4 to 30 weight percent, with a most preferred range of 4.5 to 25 weight
percent.
Glass-based fillers were used not only to improve the physical properties
of the Gnal materials, but also to improve heat transfer from within the
material
during crystal formation period. Since crystallization is a thermodynamic
process,
a rapid cooling will tend to both reduce the rate ofcrystallization and the
size of
the resulting crystalline domains. Anything that enhances the rate of heat
transfer
from within the material would also be expected to reduce the degree of
crystallization.
Alkali-free glass and alkali-containing glass are useful in the instant
invention (fox example, E glass,C glass and A glass) with E glass being
particularly preferred since it is most commonly used to reinforce engineering
resins. Preferred glass fiber is in the form of glass rovings, glass chopped
strands,
and glass yarn made of continuous glass filaments 3-20 micron meters in
diameter, commercially available as PPG 3531, PPG3GG0 and PPG 3540 from
Pittsburgh Plate Glass Company.
The refractive index o~ E-glass Fiber is 1.554 as measured by white light
and index matching fluids (Composites, Part A (1998), Volume Date 1999,
30A(2), 139-145). To keep the blends translucent, the glass refractive index
has
to be Fairly closely matched to that of the polymer matrix.
The refractive index of nylon G and nylon G,6 is 1.53 (red V-8, Pohtmer~
flrrf~rlhoak Second Ed., Brandrup, Wiley Interscience Publication).
7
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Catalyst (C).
The third component (C) is a phosphorous catalyst, which promotes
transamidation between the different semi-crystalline nylons.
Useful catalytic oxidation states of phosphorus compounds are +1, +2, and
+3. (see Plzosplror-tts: ccrt Orttlirre of its Cherrtistrll. Biochemistry,
crncl Techrrologv,
Fifth Ed., D. E. C Corbridge, Elsevier, 1995 p. 25,). For example, phosphates
and
hypophosphites of Group I, Group I1, ainc, manganese, and aluminum salts can
be
used. Phosphate and hypophosphite esters are also included. Preferred
catalysts
are sodium hypophosphite, potassium hypophosphite, and manganese
hypophosphite,
The amount of the catalyst to be added will vary depending on the blend,
the amount of glass Fber, and other factors known to those skilled in art.
However, it is effective in a surprisingly small amount, preferably ranging
from
0.1 to 0.5 weight percent and most preferably from 0.2 to 0.4 weight percent.
Other components such as pigments, dyes, anti-oxidizing agents, or
weathering agents may be incorporated into the polyamide resin composition in
the present invention in so far as they do not affect the optical properties,
moldability, and physical properties thereof. Typically such conventional
additives
are added to the composition in a mixing step and are included in an extrudate
of
the composition.
Pre arp anon.
The method of mixing the components of the polyamide formulation of the
present invention is not particularly limited, and any known method can be
employed. Blending or mixing ofthe constituents that comprise the composition
may be by any effective means that will effect their uniform dispersion. All
of the
constituents may be mixed simultaneously or separately by a mixer, blender,
kneader, roll mixer, extruder, or the like in order to assure a uniform blend
of the
constituents. In the alternative, the constituents making up the polyamide
blend
component may be blended or mixed first by a mixer, blender, kneader, roll
mixer,
extruder, or the like in order to assure a uniform blend of the polyamide
blend and
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the resultant polyamide mixture is melt-kneaded together with the glass
fibers,
catalyst, and any additives in an extruder to make a uniform blend.
The uniform composition is then extruded into strands, and subsequently
chopped into pellets. The pellets may be subsequently provided to the feed
hopper
ofa molding apparatus used for forming articles.
The novel blend is useful for both molded and film applications. The
shaped articles formed From the compositions of the present invention, are
generally formed by a known molding method for thermoplastic resins such
injection molding, extrusion molding, blow molding, transfer molding, or
vacuum
molding.
Examples
Materials.
The materials used in the examples described below were as follows:
Nylon 6,6: ZytelQ101 supplied by DuPont.
Nylon 6: Ultramidfl B3 supplied by BASF.
Amorphous nylon: ZytelOO 330 supplied by DuPont
PPG3540: Glass fibers supplied by the Pittsburgh Plate Glass Company.
SHP (sodium hypophosphite): Supplied by OxyChem as EN grade.
Al distearate (aluminum distearate): Supplied by Shepherd Chemicals.
Irganox~J 1098: Supplied by Ciba.
EastobriteQ OB-1 (4,4'-bis(2-benzoxazolyl)stilbene): Supplied by Eastman
Chemical Products, Inc.
S-EED (Nylostab~ S-EED~): Supplied by Clariant.
Material Preparation.
A 40 mm Werner & Pfleiderer twin-screw extruder was used to prepare
thoroughly mixed blends of polymers, glass fibers, catalysts, and additives.
The
temperatures used were typically 270-30D °C and the resulting melt
temperatures
were typically 280-330 °C. The extruder and screw were set up to
accommodate
main feeding and side feeding. Polymers, catalysts, and additives were fed
into
the extruder through the main feed throat and glass fibers or beads were fed
9
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the extender through the main feed throat and glass fibers or beads were fed
through a side feeder. The melting zone has to be severe enough to obtain the
intimate mixing that is required to achieve a thorough compatibilization of
multiple polyamides at the molecular level. A less severe melting zone could
lead
S to inadequate mixing, which could result, upon cooling, in the formation of
undesirably large crystals that would decrease the translucency of the
resulting
material.
By examining a given well-mixed molten polyamide blend before glass or
other i'iller is introduced to the extruder, it is possible to assess the
suitability of
the blend for a translucent mixture by visually inspecting it. A transparent
melt is
indicative of a compatible blend and a cloudy melt of an incompatible blend.
The
molten material containing all ingredients was then extruded into strands, and
chopped into pellets.
General Test Procedures.
The materials were molded into test bars. The following tests were
performed on samples dry-as-molded (DAM):
Elongation at break (EBB) and tensile strength (TSB measurements were
determined as described in ASTM D-63$ or ISO 527.
Flexural modules (FM) measurements were determined as described in
ASTM D-790 or ISO 178.
Notched Izod (NI) and unnotched (UNI) impact testing was done as
described in ASTM D-256, ASTM D-4812, or ISO 180.
Heat deflection temperatures (I-LDT) were determined as described in
ASTM D-648.
Differential scanning calorimetry (DSC) scans were taken in a TA
Instruments device. The heating and cooling ramps were 10 °C/min.
Yellowness index (YI) measurements were determined as described in
ASTM E313.
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Characterization of Translucency.
Materials from each group to be compared were molded into 1.G mm or ~
mm thick bars. The molded bars were, in turn, placed under the same lighting
conditions on top of a sheet of paper marked with a thick line or printed
words.
The markings were easily legible through the bars. Each bar was then lifted
from
the paper until the markings were no longer legible through the bar. The
distance
in millimeters between the top of the bar and the paper at the point at which
the
markings are no longer legible was used to characterize the translucency of
the
material. These numbers are given in the tables below under the heading of
'part
translucency', where the thickness of the bars used is also indicated. Bars
with a
higher degree of translucency will have longer distances indicated than less
translucent bars.
The Effect of Immiscibili~ Upon Physical Pro ep roes.
The purpose of the examples shown in Table 1 is to illustrate how physical
properties can deteriorate when two incompatible semi-crystalline polymers are
melt blended. I~lylon G,G by itself has a 55°~'o elongation at break.
Nylon 6,12
alone has an 80°,~° elongation at break. However, when
20°,~o nylon G,12 is melt
blended with 80°l° nylon 6,G, the elongation at break of the
mixfiure is only 19°~'°.
The melt has a milky appearance, which indicates that nylon G,G and nylon G,12
are not fully miscible and that this system would not be suitable for
inclusian in
transparent or translucent blends.
Table 1
i. _ _
ComparativeComparative Comparative
Example ' Example Exam 1e
1 2 3
N Ion 6,6 100 ~ 80 0
wt%
N Ion 6,12 0 20 ~ 100
wtl
Melt charactertrans arentcloud ~ clear
i
E B 55% 19% 80%
Molded partopaque opaque opaque
~ ~
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Blends of Semi-Crystalline Pol hers.
The blends used in this group of examples were made by melt-blending
two commonly used semi-crystalline polymers, nylon G,G and nylon G. Together
they formed a homogeneous melt that was totally clear, indicating that the two
polymers were compatible. PPG3540 glass fibers, a catalyst and other
ingredients
were added to the mixture as indicated in Table 2. After the materials were
prepared, each blend was molded into bars for physical testing and 1.G-mm-
thick
bars for translucency testing. The results are shown in Table 2.
The surprising results are (1) that the addition of glass fibers did not
prevent the materials from being translucent, and (2) that the addition of
glass
fibers enhanced the translucency ofthe resulting materials more in the nylon
G/nylon G,6 blends than in either the pure nylon 6 or nylon G,G systems.
That the glass fibers did not negatively impact the translucency was a
result of a combination of two factors. First, the refractive index difference
between the polyamide and PPG35~0 glass fiber is quite small. Second, the
presence of the glass probably accelerated the cooling time in the molded
part,
which would tend to lower the rate of crystallization.
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Table 2
I Comp.Comp. Comp. Comp.
Ex. ~ Ex. Ex. Ex. Ex. ~ Ex.
4 5 6 1 2 Ex. 7
3
N Ion 6,6 wt% 99.2491.24 ~ 86.2459.5 54.7 55.90
i N Ion 6 wtl 0 0 0 39.7 36.5 I ~ 94
37.3
SHP wtl 0_10 0.10 0.10 0.10 0.10 '~ 0
0.10
Ir anox 1098 wtl 0.50 0.50 ~ 0.500.50 0.50 0.500
Eastobrite OB-1 wtl 0.01 0.01 0.01 0_01 ' ~ ' 0
0.01 0.01
AI distearate wt% 0.15 0.15 I 0.15~ 0_15 0.150
0.15
PPG3540 wtlo ~ 8 i 13 ~ 8 6 6
0 0
Part translucenc 1.6 3 I 4 3 5 7 ~ 4
mm mm ~ 8
I TS k si _11.816.1 17.4 8.7 14 14.314.8
'~
E B l _ 29 3.2 3 36.5 3.2 4.4 12
I
NI 23 C ft-Ib/in I 0.92 0 0.79 1.33 0.64 0.851.03
~ ,62 I
I~
HDT 264 .s.i. C 76 _ 243 56 209 198 221
240 ~ I
i
FM k si 457 660 754 434 611 535 595
I ~ ~
I I
YI 2.7 2.1 1.7 2.6 1_1 2 7
I
DSC Analysis Results.
DSC analysis was used to characterize the effect of using a catalyst, which,
in these examples, was SHP. Melting and freezing points (abbreviated MP and
FP, respectively, and the corresponding heats of fusion and crystallization
were
determined for two successive cycles of heating and cooling.
bleats of fusion and crystallization are reflective of the degree of
crystallinity possessed by a material. Lf, in the ease of a blend, the melting
point,
freezing point, and associated heats have changed between the first and second
heating and cooling cycles, that is a good indication that chemical reactions
between the various components have occurred.
This is illustrated by the examples given in Table 3. In the case of a single
polymer such as nylon 6,6, there is no significant change in the melting
point,
breezing point, and associated heats between the Grst and second heating and
cooling cycles. However, in the multi-polyamide systems, a significant
reduction
is
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of the melting points, freezing points, and associated heats is observed
between
the two heating and cooling cycles. This is a good indication that a
transamidation reaction between the nylon G and nylon 6,6 components has taken
place and reduced the degree of crystallinity. The result is a system in which
enough crystallinity is preserved to maintain good physical properties, but in
which the crystalline domains have been reduced sufficiently to allow for
significantly improved optical properties.
Table 3
Comp.I Comp.,Comp. comp.
Ex. Ex. Ex. I Ex. Ex. Ex.
4 5 6 Ex. 2 3 7
1
N Ion 6,6 wtl 99.2491.24 86.2459.554.7 55.9~
94
N Ion 6 wtl 0 0 0 39.736.5 37.30
SHP wt% 0.10 ~ 0.100.10 ~ 0.10 0.10I
0.10 0
Ir anox 1098 wtl 0.50 0.50 0.50 ' ~ 0.50~
0.500.50 0
Eastobrite OB-1 ~ ~ 0.010.01 0.01~ 0.01'
wtl 0.01 0.01 0
AI distearate wt% ~ ~ 0.15~ i ~ ~ '~
0.15 0.15 0.150.15 0.150
PPG3540 wtl 0 8 ~ 0 ~ ~ 6
13 8 6
1 St MP C 263 263.8 263.9253.8' ' ~
257.4258 261
15t Heat of fusion69.4 63.7 58,6 61 54 54.768
Jl
15r FP C 231.4231.3 ~ I ~ 216.5229
230.7209.6215.8
1 $t Heat of crystallization
J/ 60.7 55.7 53 ' 44.9 54.8~
58.7 54.7
2"d MP C 263 263 263.4249.9254.4253 262
~ ~ '
i
2"d Heat of fusion69.9 65 60.7 35 38 36.963.9
J/ ' ~ i
2"d FP C 230.5230.3 229.4205.8210 209 229
I '' '
I 2"d Heat of crystallization
J/ 58.2 53.7 50,7 53,448 51.554.8
~ i '
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Semi-Crystalline Polyamides Blended With an Amorphous Polyamide.
In these examples, two semi-crystalline polyamides, nylon G and nylon 6,G
were blended with glass fibers, a catalyst, additives, and an amorphous
polyamide.
The amorphous polyamide, which has a refractive index of 1.588, was
synthesized by condensation polymerization. The diamines used are bis(p-
aminocyclohexyl)methane, and hexamethylenediamine. The diacids used are
isophthalic acid and terephthalic acid. The amorphous polyamide is Fully
miscible with nylon G and nylon 6,G at all concentrations and the ternary
mixture
forms a transparent melt.
The blends were molded into 4-mm-think bars and the translucency test
described above was applied. The translucency and physical testing results for
six
different compositions are given in Table 4. The presence of the amorphous
resin
has improved the optical properties of the resulting materials, but the
presence of
the semi-crystalline components and glass fibers has endowed fine materials
with
good physical properties
l5
CA 02420446 2003-02-24
WO 02/31053 PCT/USO1/42587
Table 4
Ex.4 ~ Ex.5Ex.6 Ex.7 Ex.8 I Ex.9
N Ion 6,6 wt% 28.2 ~ 31.132.7 27.3 27.3 22_8
N Ion 6 wtl 18.8 20.7 21.8 18.2 18.2 15.1
_. - _ .. _ _
Amor hous of amide 46.9 42.3 36.4 45.5 45.5 30.9
wtl
PPG3540 wtl 4,9 4.9 7.9 7.9 7.9 30
SHP wt% 0.3 0.3 0.3 0.3 0.3 0.3
i
Eastobrite OB-1 wt% 0.01 0.01 0.01 0.01 0.01 0.01
- ..
' Ir anox 1098 wtl 0.4 0.4 ~ 0.4 0.4 0.4 I 0.4
S-EED wtl 0_15 0.15 0.15 0.15 0.15 0.15
AI distearate wt% I 0_3 I 0.3 I 0.3 0_3 I 0.3 0.3
Part translucenc 4 20 29 14 10 ~ 15 7
mm mm
FM MPa 3663 3417 3627 ' 3676 3878 5933
TS MPa 82.9 105.3 nt nt 117.1 ~ 168.9
N ( 23 C J/m 26.4 32.5 27.4 32.2 ~ 32.457.9
'
UNI 23 C J/m 316.8 319,1 295.3 ~ 330.5334.3 ~~ 365.0
NI -20 C J/m nt I nt 32.1 34.2 nt nt
UNI -20 C Jlm nt nt i 331,1364.3 nt nt
nt = not tested
16
