Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
Field of the Invention
This invention is directed to a novel composition
of matter. The composition is a particular nylon copolymer
having utility as a fiber.
Description of the Prior A _
The poly(4,7-dioxadecamethylene adipamide)-polycaprolactam
block copolymer, referred to hereinafter as N-30203-6//6, is
disclosed in my U.S. Patent 4,130,602, issued December 19, 1978.
~iethod for making such a polymer is also disclosed therein. The
block copolymer N-30203-6//6 has utility as a hydrophilic fiber.
While it also has other favorable properties sueh as tenacity,
elongation and initial modulus, it can have a fusion problem
as deseribed hereinafter.
To form a fabric from a block copolymer N-30203-6//6,
the eopolymer is spun into a fiber by known means. While spinning
the fiber, a lubrieating finish is applied to the fiber to
faeilitate subsequent processing steps. After the copolymer
is spun, it is drawn and then annealed to stabilize the drawning.
The resulting fiber is knitted into a tube and then, to wash
off the finish applied earlier, it is placed in boiling water.
During this washing off in the boiling water, the copolymer fibers
have a tendency to fuse together. (The washing off in boiling
water is referred to as scouring.) This fusion causes the
knitted fabric to become stiff which is unacceptable to a
wearer.
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SU~RY
It has been discovered that if a small portion of
the adipic acid in the N-30203-6 portion of the block copolymer
N-30203-6//6 is replaced with terephthalic acid (hereinafter
referred to as T), the aforementioned fusion problem is
eliminated. Surprisingly the resulting copolymer maintains
the desirable hydrophillic tenacity, elongation and initial
modulus properties of N-30203-6//6.
DESCRIPTION
The copolymer of my discovery has the following
structural formula:
1S l~r-(CH2)3-O-(CH2)2-o-(cH2)3-N-c x t ~cH2~s
Y Z
wherein
x is between from about 97 weight % to about 93
weight % of the bivalent radical -(CH2)4-, and the
balance is para-phenylene
and
y = 4-200
z = ~-200
and the copolymer has a molecular weight of within the range of
about 5000 - 100,000.
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The ether-amide portion of the copolymer can be
prepared by the following scheme:
H H H H H
N-C-CH + HO(CH2)2OHN-C-C-C-O-(CH2)2O-C-C-C-N (l)
(I) (II) (III)
FI H HH
O (CH ) O-CC-C-N + 4H2-~ NH2-(CH2)3 ( 2 2 2
(III) (IV)
NH2-(CH2)3-O-~CH2~2-O-(CH2)3-NH2 + HOC-(CH2)4-C-OH (3)
O O
(IV) (V)
( 3 (CH2)3 (CH2)2 O(CH2)3-NH3 ) (OC-(CH2)4-C-O)
O O
(4)
(VI)
3 ( 2)3 (CH2)2-O-(CH2)3-NH3 )(OC- ~ -C-O)
O O
(VII)
H H H
) tCH ) -N-~-(CH2)4-C-)(-N (C~2)3 2 2
O O O O
(VIII)
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Aforementioned reaction (:L) is often referred to
as cyanoethylation; it is between acrylonitrile, I, and ethylene
glycol, II, and results in 1,2-bis ( -cyanoethoxyethane), III.
Reaction (2) is the hydrogenation of compound III to the diamine
(i.e., 4,7-dioxadecamethylenediamine), IV. The diamine, IV, is
reacted with adipic acid, V, to form the salt, VI, in reaction
(3). To prepare the analogous terephthalic salt, the afore-
mentioned reactions (1) - (3) can be duplicated except that
in reaction (3) in place of adipic acid, terephthalic acid is
used. Then the two salts, i.e., VI and VII, are polymerized
by heating to form the random copolymer, VIII. The latter
contains N-30203-6 and N-30203-T. Thus the random copolymer
can be represented as N-30203-6/T.
The amount of adipic acid used to prepare the afore-
mentioned salt VI is such that it constitutes between about 97
weight % to about 87 weight $ of the total diacid that could
be used to react with the diamine IV. The balance of the acid
used is T and amounts to between about 3 weight % to about 13.5
weight %. If less than about 3 weight % of T is used, the fusion
problem is not corrected whereas if much more than about 13 weight
% of T is used, then the other properties may deteriorate too much.
The other portion of the copolymer of present invention
I H
is L-N-(CH2)5-C- which is also known as a bivalent radical of
nylon-6 or N-6. The latter is available commercially and methods
for preparing it are well known and abundantly disclosed in numerous
publications.
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As indicated, the aforementioned portions of N-30203-6/T
and N-6 each can contain as few as 4 repeating units within the
copolymer of present invention. Thus, both x and y can equal 4.
As reported in my previously referred to application, 4 represents
the lowest value that the components can be present and still
retain its own particular properties without substantially
degrading the properties of the other repeating units. To
minimize loss of properties, the preferred minimum values for y
and z are 8 and more preferred values are 10. While values of
z of 200 are operative, preferred maximum values of y and z are
175 and 185 with values of 150 and 160 more preferred.
The process used to prepare the copolymer involves a
process known as melt blending. In melt blending two different
polyamides are mixed together and heated to a temperature which
ranges from above both their melting points to below both their
decomposition temperatures. The length of time the mixture is
maintained within the temperature range has a profound effect on
the resulting structure. As the mixing with the aforementioned
temperature range begins the mass is a physical mixture of two
different compounds. But gradually as the heating and mixing
continues, the mixture is converted into a copolymer characterized
as a "block" copolymer. However, if the heating and mixing
continues, the length of the "blocks" decreases and sequences of
"random" copolymers appear. If the heating and mixing occurs
for a sufficient time, most of the "blocks" disappear and mostly
"random" sequences form as evidenced by deterioration of its
physical properties, including melting point. Use of a higher
temperature within the aforementioned range reduces the time
necessary to~ achieve the desired amount of block formation at a
lower temperature. At present there is no known direct way
of determining chain sequence of such a polymer. But indirect
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methods exist, and these are known to those skilled in the art.
Controlled decomposition of such a copolymer will yield all
identifiable components that make up the copolymer but will not
indicate sequences.
Melt Blending can be used to prepare N-30203-6/T//6.
Desired amounts of N-30203-6/T are blended with suitable amounts
of N-6. The resulting mixture is heated to a temperature which
ranges from above the melting point of each to below the decomposition
temperature of each. While within this temperature range, the
mixture is mixed until the desired amount of blocks are formed. The
time for mixing at the elevated temperature depends upon how much
material is present, the amount of mixing occurring, the type of
equipment used, and the like.
The copolymer of the invention can also contain an
antioxidant, delusterant, light stabilizer, and other such additives.
The additives can be incorporated, e.g. prior to the melt blending
or during the melt blending or afterwards.
The following examples illustrate further my invention.
EXAMPLES
A random N-30203-6/T, containing by weight 80% of
N-30203-6 and 20% of N-30203-6/T, was prepared in the following
manner. Eight grans of N-30203-T salt were mixed with 32 grams
of N-30203-6 salt. Both salts were prepared by the previously
discussed scheme, i.e. reactions 1-3. The resulting mixture of
the two salts were changed to a heavy walled polymer tube. In
addition 0.04 grams of benzoic acid were changed to the tube.
Its function was to control the polymer's molecular weight
as represented by the resulting viscosity; its use is optional.
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In addition 0.04 grams of H3PO3 were changed to the tube. Its
function is to serve as a catalyst, against its use is optional.
After purging the tube with a nitrogen-vacuum cycle the tube
was evacuated and sealed. The tube was placed in an aluminl~m
heating block and the tube's temperature raised to 190C. It
was maintained at that level for 2 hours. The tube was then
opened and while an atmosphere of nitrogen was maintained its
temperature was raised to 245C and maintained at that level for
half an hour. Then while the sample was still at 245C the
nitrogen was removed and while in a vacuum the temperature was
maintained for another hour. A sealed tube was used initially
to prevent any monomer from distilling off. The lower temperature
was used to slowly build up the molecular weight until a higher
temperature could be used. After the final heating at 245C
the material was cooled, chopped and dried for the subsequent
melt blending step.
A second random N-30203-6/T, containing by weight 60% of
N-30203-6 and 40% of N-30203-T, was prepared in an analogous manner
except that the amounts of the salts used were different. A third
random N-30203-6-T was prepared containing 20% of N-30203-6 and
80% of N-30203-T.
The first prepared N-30203-6/T copolymer was melt blended
in the following manner. Seventy three grams of the polymer (80%
of 6 and 20% of T) was mixed with 170.3 grams of N-6 and then dried
by heating to 80C. The resulting dried mixture was charged to a
suitable lass tube containing a stainless steel helical stirrer.
The tube was purged of air with nitrogen and heated to 282C using
a vapor bath of dimethyl phthalate and stirred for 30 minutes. Upon
cooling the resulting N-30203-6/T/6 was removed from the tubes,
chopped and dried. In this copolymer the -(CH2)4- bivalent radical
amounts to 97% of the x defined in Claim 1.
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The second prepared N-30203-6/T copolymer was melt
blended as previously described except that 75 grans of the
N-30203-6/T copolymer (60% of 6 and 40% of T) and 175 grams of
N-6 were used. In the resulting copolymer of N-30203-6/T//6 the
-(CH2)4- bivalent radical amounts to 93.5% of the "x" defined in
Claim 1.
The third prepared N-30203-6/T was melt blended as
previously described except that 60 grams of N-30203-6/T (20%
of 6 and 80% of T) were used. In the resulting copolymer of
N-30203-6/T//6 the -(CH2)4- bivalent radical amounts to 87.5% of the
"x" defined in Claim 1.
A comparative N-30203-6//6 sample was also prepared
by heating and mixing at 282C for 26 minutes.
Samples of the three N-30203-6/T//6 copolymers along
with the N-30203-6//6 were individually spun into a fiber using
a ram-extruder. The samples were spun through a spinneret having
7 orifices 12 mils in diameter and 24 miles in length. The dried
samples, about 50 grams, were changed to the extruder and allowed
25 minutes to melt and reach an equilibrium temperature i.e., about
230C. Then the samples were forced through screen filters, 40
mesh and 250 mesh stainless steel screens and the spinneret by
a motor-driven ram. The samples of N-30203-6//6 were melt spun at
a suitable feed rate. The samples of N-30203-6/T//6 were spun at
a feed rate of about 1.6 cm /min. The yarns were passed from the
spinneret through guides and were collected on paper tubes at
a take-up speed of 138 ft./min. A spin finish, which is commercially
available and which had been dissolved in heptane, was applied to
each yarn as it passed over an applicator. The applicator was a
nylon felt saturated with a spin finish and was attached to the ~`
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yarn guide located about 4 feet below the spinneret. During each
of the spinning steps the block temperature of the extruder was
about 225C while the ram pressure for the sample containing 3% T
was 400 psig whereas it was 535 psig for the sample containing
6.5% T. The pressure for the 12.5% T sample was 670 psig and
the temperature was 232C.
After the fiber spun was drawn and then annealed to
stabilize the drawing the resulting stabilized fiber was knitted
into a tube, and placed in boiling water. After cooling the
tube was deknitted. During the deknitting step no fiber fusion
was found for any of the three N-30203-6/T//6 samples.
Samples of the three N-30203-6/T//6 copolymers were
tested as to water retention (LA. Welco, H.M. Zufle and
A.W. McDonald, Textile Research Journal, 22, 261 (1952)). The
amount of water retention versus the amount of T in the copolymer
is as follows:
%T % Water Retention
0 28
3.5 26
6.5 23
12.5 19
In contrast during the deknitting step for the tube
made of N-30203-6//6 polymer a small number of fibers were found
fused together. While the amount of fusion was labeled small,
the amount was sufficient to make it unacceptable as a commercial
fabric.
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