Note: Descriptions are shown in the official language in which they were submitted.
~51~i9~ :
This invention relates to new and imprvved high
molecular weight modified polyestexs. More particularly this
invention relates to fiber-forming modified polyesters having
improved dyeability and affinity for basic dyes, and to
methods for making said modified polyesters.
Polymeric linear polyesters are readily prepared by
heating together dihydric alcohols or functional derivatives
thereof and dibasic carboxylic acids or polyester-forming
derivatives thereof such as acid halides, salts, or simple
esters of volatile alcohols. Highly polymerized polyesters
can be formed into filaments, fibers, films and the like which
can be permanently oriented. The most widely known and most
important commercially of the polymeric polyesters is that
prepared by the condensation of terephthalic acid or dimethyl
terephthalate and ethylene glycol. These polyester materials
in drawn fiber or filament form cannot be satisfactorily dyed
by the ordinary dyeing procedures used in dyeing cotton,
wool, natural silk, and regenerated cellulose. It is recog-
nized that unless the fiber-forming polyesters can be readily
dyed by commercial dyeing processes, the utility of the polymer
in the textile field will be limitedO The compact structure
of po~yethylene terephthalate fibers, the molecules of which
are closely packed along the axis of the fiber, makes it quite
difficult, except with a limited number of dyes, and under
extreme conditions of temperature and pressure, to obtain a
satisfactory degree of dye-bath exhaustion, or to secure -
satisfa~tory deep shades in the fibers. Absorption and pene-
tration of the dye into the fiber core are limited by inherent
properties of the fiber.
A number of methods have been proposed to
increase the dyeability of the polyesters and particularly
-2~
~L~5159~
polyethylene texephthalate. However, the methods proposed
to date have not proved to be entirely satisfactory.
Modification of the polyesters by incorporating dye
sites in the polymers by selected comonomers ordinarily does
not produce satisfactory fiber-forming materials, i.e., the
dye affinity may be enhanced but other physical properties
such as tenacity, melting point and the like are adversely
affected. Accordingly, the art has striven for means to in-
crease the dyeability of polyester structures, such as fiber,
filaments, films, and the like without adversely affecting
other necessary physical properties.
One such method used successfully to improve the `
dye affinity of polyesters for dispersed acetate dyes and
basic dyes is to conduct the polyester reaction in the pre- ;;
sence of a small amount of a difunctional agent which pos,
sesses a metallo sulfonate group or sulfonate-forming group
and two functional or reactive groups such as hydroxyl or car-
boxyl and esters thereof. By this novel technique, modified
polyesters can be produced which not only possess improved dye `
affinity for dispersed acetate dyes and basic dyes under
. - .
moderate temperature and pressure and~or with carriers, but ` `
also the modified polyesters have the necessary molecular ;;
weight required for fiber-forming polyesters and excellent
physical properties in fiber form. However it has been found
that when starting with terephthalic acid and ethylene glycol, , -
such modification of polyesters often fails to produce satis-
factory fiber-forming materials. Attempts to conduct a con-
tinuous esterification reaction of terephthalic acid and
ethylene glycol in the presence of such sulfonate-containing
compounds as, for example, S-sodium sulfo isophthalic acid
has resulted in excessive diethylene glycol formation,
-3
: ........ . ~.. - . :. . . . .
~5159~ :
resulting in a polymer with a low mel-ting point and poor
heat and light stability in the fiber prepared therefrom.
It is an object of this invention to provide an
improved method of continuously producing high molecular
weight fiber-forming polyesters which have improved dyeing
characteristics, including increased affinity for basic dye
stuffs, which polyesters also have a useful balance of other
desireable physical properties including high molecular weight,
high melting point, and good heat and light stability.
Other objects and advantages of this invention will
be apparent from the description thereof which follows.
The objects of this invention are accomplished by
reacting continuously under polyesterification conditions an
aromatic dicarboxylic acid and a polymethylene glycol to form
a prepolymer having a carboxyl level of not more than 2000~ `
eq/g and an intrinsic viscosity of not more than 0.10, which ;`~
is then reacted continuously with a glycol solution of a bis
glycol ester of a difunctional aromatic compound possessïng
one or more metallo sulfonate groups and of such concentration
that the resulting total glycol/total dicarboxylic acid moiety
ratio is at least about 1.6; or by reacting continuously or
non-continuously under polyesterification conditions an
aromatic dicarboxylic acid and a polymethylene glycol to form
a prepolymer having a carboxyl level of not more than 2000
eq/g and an intrinsic viscosity of not more than 0.07 which is
then reacted non-continuously with a glycol solution of a bis
glycol ester of a difunctional aromatic compound possessing
one or more metallo sulfonate groups ancl of such concentration ~`
that the resulting glycol/dicarboxylic acid moiety ratio is
at least about 1.6. Excess glycol polymer obtained is equiva- ~ ;
lent to polymers obtained using dimeth~l terephthalate as a ` ~ `
--4--
,, . : :, : - .: :
- . .: . - . - : .
- .: ,, -
. . :, . . :- : :
~5~5~
starting material, but does not contain the excessive
diethylene glycol which otherwise results in the praparation
of cationic dyeable polyesters starting from terephthalic
acid.
Generally, the process for producing polyesters
using the method of this invention ordinarily comprises pre-
paration either continuously or batchwise forming a reaction
mixture comprising an aromatic dicarboxylic acid and an excess
of polymethylene glycol. Other additives, such as catalyst,
chain branching agents, chain terminating agents and/or-cross -
linking agents and the like may also be added with the initial
ingredients if desired. In one embodiment of this invention
the reaction mixture is then heated to an elevated temperature
sufficient to start the reaction between the acid and the
glycol, with the elevated temperature being maintained until ; ~ ~ `
the reaction is substantially completed as indicated by the ~ -
cessation of the evolution of the water of reaction, whereby
a small amount of monomer and a predominate amount of oligo~
mers and polymers of a low degree of polymerization are formed.
During this stage of the reaction, the temperature must be
such that the water formed is continuously removed by dis- `~
tillation. It may be desirable, although certainly not
necessary, to conduct this stage of the reaction under a
pressure of from about S psig to 100 psig in order to acceler-
ate the reaction and produce a low molecular weight prepoly-
mer. At a point when the degree of esterification of the ~ -
prepolymer is greater than 80%, as indicated by a carboxyl
level of not more than ~000fL eq/g (ordinarily at above 80%
of esterification), and when the prepolymer has an intrinsic
viscosity of not more than about 0.07, the preformed bis
glycol ester of the sulfonate-containing compound is added in
~L()S1~93~
an amount and of such concentration that the resulting
glycol/dicarboxylic acid moiety ratio is at least about 1.6.
The temperature of the reaction mixture may be raised to
remove excess glycol and to condense the resulting inter-
mediate product to a highly polymerized polyester.
In another embodiment, the reaction mixture is
metered continuously into a reactor operating at an elevated
temperature sufficient to promote the reaction between the ;
acid and the glycol. Preferably the esterification reaction
is substantially completed in a single stirred-tank reactor;
however, two or more reactors may be used to yield a product
which normally consists of a small amount of monomer and a
predominate amount of oligomers and polymers of a low degree
of polymerization. During this stage of the reaction, the
temperature must be such that the water formed is continu-
ously removed by distillation. It may be desirable, although
certainly not necessary, to conduct this stage of the reaction
under a pressure of from about 5 ps:ig to 100 psig in order to
accelerate the reaction and produce a low molecular weight
prepolymer. At a point when the degree of esterification of
the prepolymer, as indicated by a carboxyl level o~ not more
than 2000~ eq/g tordinarily at about 78% esterificatinn), and
when the prepolymer has an intrinsic viscosity of not more
than 0.10, the preformed bis glycol ester of the sulfonate- -
containing compound is added continuously as a glycol solu- ;`
tion or slurry of such concentration that the resulting total ;
glyc~l/total dicarboxylic acid moiety ratio is at least about
1.6.
In either process, the temperature of the reaction
mixture may be raised ~the pressura decreased and/or a dry
inert gas sweep used] to ramove excess glycol and to condense
~5~.59~
the resulting intermediate product to a highly polymerized
polyester. The excess glycol present after the addition of
bis glycol ester is removed under reiatively mild conditions --
with the temperature not to exceed 300C and preferably not
to exceed 260C in conjunction with low pressure or inert
gas sweep -- in order to minimize etherification of the glycol.
The condensation reaction is preferably conducted in a series "
of two and preferably more than two reactors generally opera-
ting at reduced pressure to aid in removal of the glycol con-
densation by-product. The reaction preferably is carried out
in an oxygen free atmosphere.
The dicarboxylic acid employed is preferably tere-
phthalic acid in view of its commercial availability at a
relatively low cost and in view of the desirable properties .
?
of the polymer that can be produced by using this specific `~
acid. Aromatic dicarboxylic acids which may be used in accor- ;
dance with the present invention include those having the `~
general formula ~ :~
HOOC - ~ ~(R)n - COOE~
wherein n is either zero or one, and R is a radical selected
from the group consisting of ~a) an alkylene radical contain-
ing 1 to 8 carbon atom~; `
(b) - ~ -
wherein Rl is an alkylene group containing 1 to 8 carbon
atoms;
(d) - O - R2 ~ ~ ~
wherein R2 is an alkyle~e group containing 1 to 8 carbon
-7-
:; . , : . : - ............................... : -
. : : , , . , ~
1~51~9~
atoms; and
(e) _ o - R3 - -
wherein R3 is an alkylene group containing from 1 to 8 carbon ~;
atoms.
As examples of suitable aromatic p-dicarboxylic
acids having the above general ~ormulas there may be named:
terephthalic acid, p,p'-dicarboxydiphenyl; p,p'-dicarboxy-
diphenylmethane; p,p'-dicarboxydiphenylethane; p,p'-dicarboxy-
diphenylpropane; p,p'-dicarboxydiphenylbutane; p,p'-dicarboxydi-
phenylpentane; p,p'-dicarboxydiphenylhexane; p,p'-dicarboxy-
diphenylheptane; p,p'-dicarboxydiphenyloctane; p,p'-dicarboxy-
diphenoxymethane; p,p'-dicarboxydiphenoxyethane; p,p'-dicar-
boxydiphenoxypropane; p,p'-dicarboxydiphenoxybutane; p,p'- ~
dicarboxydiphenoxypentane; p,p'-dicarboxydiphenoxyhexane and ~`
the like. Other useful aromatic dicarboxylic acids that may
be used include naphthalene dicarboxylic acids such as 2,6-
dicarboxynaphthalene, 2,7-dicarboxynaphthalene, and the like. `~
Copolyesters can also be prepared in accordance with
- the present invention. For example, mixtures of the aromatic
p-dicarboxylic acids defined above or these acids mixed with `
up to 50 weight percent of an aromatic m-dicarboxylic acid
such as isophthalic acid or xylidinic acid may be employed
to make a polyester having particularly desirable physical
properties. It is necessary that the sole reactive gro~ps of
the acid be the two carboxyl groups. Therefore, it will be
appreciated that the aromatic dicaxboxylic acid may contain
substituents that do not enter into the polycondensation
reaction. For example, durene, 1,4-dicarboxylic acid may be
employed. The invention also includes processes as des- `~
cribed above wherein polyesters can be prepared by replacing
in part the aromatic dibasic carboxylic acid with up to
~,
-8~
~5~L591
30 percent by weight of an aliphatic dicarboxylic acid,
such as succinic acid, adipic acid, sebacic acid, alpha,
alpha~dimethylglutaric acid, itaconic acid, beta-oxydipropionic
acid, alpha, alpha-oxydibutyric acid, fumaric acid, and the --
like. Longer chain aliphatic dicarboxylic acids such as 1,20~
eiconsanedioic acid, 8-ethyl-1, 18-octadecanedioic acid, a ~ ~-
mixture thereof, and the like may also be substituted in part
for the aromatic dicarboxylic acid. For the purposes of this
invention, "polyesters" will be considered to include at least `
85~ by weight of the ester of a dihydric alcohol and a dicar-
boxylic acid.
:- ,',,: :'
The polymethylene glycol employed in the process
of the present invention may be any glycol containing 2 to 10
carbon atoms or polyester-forming derivatives thereof, and
more preferably are polymethylene glycols of the general
formula ~O(CH2)nOH, wherein n is an integer from 2 to 10 and
cyclohexane dimethanol. Illustrative of suitable aliphatic
~ycols that may be used for the purposes of this invention ~ -
are ethylene glycol, 1,5-pentanediol, 1,3-propanediol, 1,~-
hexanediol, 1,7-heptanediol! 1,8-octanediol, l,9-nonanediol,
l,10-decanediol and the like. It is preferred that the glycol
used be ethylene glycol.
At least about one molar proportion of the glycol
per molar proportion of the acid is employed. However, a
molar excess o the glycol is usually employed in the prepara-
tion of polyesters. Normally, from about 1.3 to 5 moles of
glycol per mole of acid are used.
The sul~onate-containing compound of which the bis-
ester is employed, is any organic compound containing at least ;~
one sulfonate group and capable of entering into a polyesteri-
fication reaction. The sulfonate-containing additive will
_g_ : ~ ,
~, . . .
.. . . . ~ .: :
1~5159~
react with the dicarboxylic acid and the polymethylene glycol
prepolymer and will form an integral part of the polymer
structure.
Illustrative of sulfonate-containing compounds which
may be employed for the purposes of this invention are com-
pounds of the formula
r 2)n (Y)y~X~(Z)y~ - (CH2) , - ~B)
3 )x
wherein
(a) -X- ~-
(SO3M)X ~ ~;
is a member of the class consisting of a metallic salt of a
divalent arylene radical, each being of such character that
the - SO3M - groups present are separated from ester-forming ~ `~
units by at least 3 carbon atoms ancl x is an integer of 1 to 2,
, .... . .
(b) Y and Z are selected from the group consisting ~ -`
of oxyalkyl~ oxyaryl, oxyalkyleneoxyaryl and poly(oxypoly-
methylene) oxyaryl radicals and y and y' are integers of 0 to
(c) n and n' are integers of 0 to 10, and
(d) A is a member selected from the ester-forming
units COOH, COOR, R representing a lower alkyl group of 1 to
S carbon atoms, B is a member selected from the group con-
sisting of A and hydrogen, and r is an integer of 1 to 2,
with the proviso that when r is 2, then B must be hydrogen.
These compounds are well known in the prior art, `
and descriptions of such compounds may be found in U.S.
patents 3,018,272; 3,033~824; 3,077,493; 3,164,566; 3,164,567;
3,164,570; 3jl84,434; 3,166,531; and 3,185,671. Preferred c
is the bis glycol ester of 5-sodium sulfo isophthalic acid,
'~' .-.
-10-
': :
~51591
which is prepared separately from dimethyl-5-sodium sulfo
isophthalate and ethylene glycol or by esterification of 5-
sodium sulfo isophthalic acid. The bis glycol ester is pre-
pared as a solution in ethylene glycol and fed to the pre-
formed acid glycol prepolymer as described above.
It is difficult to prepare the cationic dyeable ~ ;~
polyester polymer from terephthalic acid (as opposed to
dimethyl terephthalate) employing, for example, 5-potassium
sulfo isophthalic acid or 5-sodium sulfo isophthalic acid
because of excessive side reactions in which diethylene glycol ~ `
(DEG) is produced. Efforts to minimize these side reactions
have resulted in the finding that the addition of certain
basic salts such as lithium acetate to the formulation greatly `
reduced DEG formation, but the use of basic salts to depress
the formation of DEG in continuous processes was not às suc-
cessful as in batch processes and some cationic dyeability
was lost.
Other attempts to minimize formation of diethylene
glycol in preparing cationic dyeable polyesters from tereph~
thalic acid included the use of esters such as dimethyl-5- `potassium sulfo isophthalate in lieu of the free acid, 5- ~;
potassium sulfo isophthalic acid in an attempt to lower DEG
formation by using a less acidic reaction media during esteri-
fication, it being known that DEG formation is acid catalyzed.
High levels of DEG were generated, and a generally poor
polymer was produced. Low melting point, poor spinning and
drawing were noted.
The following examples are cited to illustrate the
invention. They are not intended to limit it in any way.
: : ; . . . .. .
;31 591 - :
EXAMPLE 1
For the preparation of the bis glycol ester from
the dimethyl ester, a three-gallon (11~35 liters) stirred-tank
reactor equipped with rectification column and condenser was
charged with 3333 grams of sodium 5-sulfo-dimethylisophthalate,
5586 grams of ethylene glycol and 22.8 grams of lithium
acetate dihydrate. The reactor was purged with nitrogen and
put under a 5 psig ~.21 kgs per square cm gauge) nitrogen
blanket prior to start of the heating cycle. When the reaction
mixture temperature reached 140C, which is slightly below
the temperature at which significant transesterification takes
place, the reactor pressure was reduced to atmospheric by -
gradually releasing nitrogen through the rectification column
and condenser. In approximately 45 minutes after beginning
the heating cycle, the reaction mixt~lre reached 180~. After
maintaining this temperature for 10 minutes, the temperature
was increased to 200C at a rate of 5C per 10 minutes. To
minimize loss of ethylene glycol during distillation of the
methanol by-product, the top of the packed rectification
column was maintained at 66 to 70C by controlling the reflux
rate to the column. The mixture was held at 200C for 40
minutes, the heat to the reactor and reflux to the column
..~. .
were stopped and the batch forced by nitrogen pressure through
a nominal 5~ glass fiber filter into a nitrogen blanketed
receiver. The solution containing approximately 48 weight
percent of the bis-glycol ester was cooled and further diluted
with ethylene glycol to 21 weight percent. The theoretical ;1
degree of polymeri2ation of the bis-glycol ester was 1.14.
Analytical tests showed a carboxyl concentration of 13f*eq~gm ;~
of the bis glycol ester, a carboxylate concentration of 60
eq/gm of the bis glycol ester and a diethylene glycol concen~
tration (DEG) of 0.56 weight percent based on weight of the
-12- ' ;
. . . .: .- .. - .. . .
105~9~ -'.. , '
bis glycol ester.
While this example employs a mole ratio of ethylene ~ ~ -
glycol to dimethyl-5-sodium sulfo isophthalate of 8 to l,
other mole ratios can be employed, so long as there is an `
excess of ethylene glycol. Ratios of 4:1 have been effectively
employed. Any common ester-interchange catalyst may be used.
For storage at ambient temperature over long periods of time
it is advantageous to dilute the reaction product to 20-22%
bis glycol ester to prevent crystallization of the bis glycol
ester.
EXAMPLE 2
For the preparation of the bis glycol ester from the
acid, a three-gallon (11.35 liters) stirred-tank reactor
equipped with rectification column and condenser was charged
with 3,018 grams of sodium-5-sulfoisophthalic acid, 5,586
grams of ethylene glycol and 30.0 grams of lithium acetate
dihydrate. The reactor was purged with nitrogen and put under
a 5 psig (0.21 kgs per square cm gauge) nitrogen blanket prior `~
to start of the heat-up cycle. When the reaction mixture `
temperature reaehed 180C, which is slightly below the tempera-
ture at which significant esterification takes place, the
reactor pressure was reduced to atmospheric by gradually
releasing nitrogen through the rectification column and con~
denser. In approximately 35 minutes after beginning th
heat-up cycle, the reaction mixture reached 190C. After
maintaining this temperature for 10 minutes, the temperature
was increased to 205C at a rate of 5C per lO minutes~ To
minimize loss of ethylene glycol during distillation of the
water by-product, the top of the packed rectification column
was maintained at 101 to 106C by controlling the reflux rate
."~
-13-
~ ~ .
~L~51S9~L -
to the column. The mixture was held at 205 C for 60 minutes
then the heat to reactor and the reflux to the column were
stopped, 50 grams of the product marketed under the trade -
mark "Darco G-60" activated carbon were added to the hot batch
and mixed for 20 minutes. (Due to the presence of i~purities
in the sodium-5-sulfo-isophthalic acid, it was necessary to ;~
decolorize the solution to obtain an almost colorless, clear
product.) The batch was then forced by nitrogen pressure from
the reactor through a Sparkler filter precoated with analytical
grade product marketed under the trade mark "Celite" filter
aid to a nitrogen blanketed receiver. The solution containing
approximately 48 weight percent of the bis-glycol ester was
cooled and further diluted with ethylene glycol to approxi-
mately 20 weight percent. The theoretical degree of polymeri-
zation o~ the bis glycol ester was 1.14. Analytical results ~;
gave a carboxyl concentration of 108~*cq/gm of the bis glycol
ester, a carboxylate concentration of 86~ cq~gm of the bis -~
glycol ester and a diethylene glycol concentration of 10 weight
percent based on weight o~ the bis glycol ester.
In the above reaction, esterification was condùcted i~-
at 205C. Lower reaction temperatures may be employed in con-
junction with longer reaction times. The lithium acetate is ~ ~ -
employed to suppress formation of diethylene glycol, and the
amount employed is not critical.
EXAMPLE 3
This example describes the preparation of a cationic
dyeable polyester via a continuous terephthalic acid (TA)
process using the ethyle~e glycol (EG) solution of the bis `-
glycol ester described in Example 1.
-14-
, ' '', : - .. . :' ., ~.~
~ 1 ~ ,,, - :
- - .... . .
~s~s9~ :
A TA-EG slurry batch containing 40.0 lbs (18143.6 g)
of TA, 30.0 lbs. (13607.7g3 o EG, 2.24 grams of penta-
erythritol, 16.80 grams of triphenyl phosphite, 13.44 grams
of lithium acetate dihydrate, 1.00 gram of a commercial
antifoam agent ~otherwise non functional) known as ~ntifoam l'A",
220.6 grams of a monohydroxyl alkoxy poly(oxyalkylene)glycol
having the structural formula:
H H
C14_15H29_31-(C ~ I ~ )1~ ~ H
H H
4.75 grams of manganese acetate tetrah~drate, 11.20 grams of
2,2'-ethylenedioxy-bis(1,3,2-dioxyastibolane) and 67.2 grams
of titanium dioxide was metered at 55.0 gm/min into a stirred_
tank reactor operating at 250C under a pressure of 20 psig ~ ` ;
(97.6 kg/m2) with a residence time of 2.5 hours. The product ~-
from this reactor had an intrinsic viscosity of 0.07 and a
carboxyl end group concentration of 760~eq/gm. By-product
water and EG were continuously distilled from the reactor and
condensed. ~ ~
This prepolymer along with 7.26 gm/min of the `;
solution of bis glycol ester described in Example 1 were
metered into a second stirred-tank reactor operating at 230C
under a reduced pressure of 260 mm Hg with a residence time of
2.3 hours. The molar ratio of total EG to TA entering the
second reactor was 1.82 and the ratio of total EG to total
dicarboxylic acid was 1.77. The product from reactor 2 had an
intrinsic viscosity of 0.~9 and a carboxyl end grou~ concen- ~ -
tration of lOO~eq/gm. Water and EG were continuously distilled
from the reactor and condensed.
-15
:.
9~
The prepolymer was further condensed in a bubble- ~ -
cap column operating at atmospheric pressure with a counter-
current flow of nitrogen at 0.34 standard cubic feet per
minute (0.160 ~/sec.). The column product was at 260C and
had an intrinsic viscosity of 0.18 and a carboxyl end group
concentration of 4~ eq/gm. Condensation was completed in a
rotating cage finisher operating at 1.6 mm Hg and 265C with a
residence time of 1.9 hours and product rate of 37.8 gm/min.
This copolymer was spun and drawn into a continuous filament
yarn having an intrinsic viscosity of 0.54, a carboxyl end
group concentration of 20~eq/gm, a diethylene glycol (DEG)
concentration of 1.5 wt. percent and melting point of 249C. ;
The yarn had a tenacity of 3.5 gm/denier, a sulfonate group
concentration of 108~eq/gm and a basic dye uptake of 103~ eq/
gm.
EXAMPLES 4-8
;l
In these examples, the same process equipment was
employed as above, with introduction of the ethylene glycol
solution containing the bis glycol ester of 5-sodium sulfo
isophthalic acid to the reactor tails of the first reactor. ~-~
The reactor tail products and the fibèr are described in the -~
following table:
-,~
-16-
. ... .,.. ,, , ,. ", . , , , ~ , , ,
~05~591
Q~O ~ o a:
o C~l ~ U) O O ~ o ~I N
.
~,
~10 . N O 0
1 ~ 0 ~ ~ 1` o o
. . . . . .
X ~ O N
~ N 1``
Q)N
~,~ O Ll~ ~ ~ ~ I` - O,
~D O O ~ ~ 1~) 0 CO N O ~I d'
W ~ N N . ~ `
~ ~ O ` ;`
X It~ ~ ~ 0 0~) N O
H li3 ~Sl N N a~ N ;; : :
~ , . ,~
a~ :: .
~ o a~ d' 0 ~0 ~D O O "
xe ~ N ~ ~ ~) O O
o ~e ~
h ~; ` ` ` ~ :~ ` .
`R ` ~ ~ .
~1 U ~
O f~ rl
U
:~ u
~ 'I ~ O . . ~ .. :~ `
: ~ QS~ne
Q ~1 0-~ 1 ~) , ~:
o h o~l 1 è IH u 3
~ e~ g ~ h ~ e E~ ~ o '~ P~ e : ~ ~
. ~ ~ q-l ~ ~ O ~ X ~ ~
o ~ - o 3 ~ ~ ~o ~ R ~ S ~
~1 u.~ u a~ . ~ .,,, :
U r~ U ~ U U ~15
~ S: ~ ~~ n o s~ a o
~ ~ H ~ ~E ~ C ~ ~ s~o U ~ ' `'
--1 7--
~L051~i93~ ~
.
O u~ ~D ~ O
~ CO ~D O ~r ~ o a~
X ~ ,, o ~ ~ o~
--I d' ~`` : `'
~ O u~ ~ ~ OD
E ....
I~ to o ~ ~1 ~P o
X ~ ~1 o u~
,
a
"
~ o n ~ ~:n nl '' '
X ~ o ~i ~i 0 ~
. . ~
,1 1~ , ..
o In ~I ,I d' ' ' "'' "
~ U7CO O O ~ I~ d' ~1 ~1 1` '"~
W ~ :~ `
..:
. . .: .-,`~,
,1 ~ ~ .~.
Q.o u~
.a ~ a~ o o ~1 ~ ~ a~ ~ 1` :'
X t`~ o ~ ~
' ~ ~ , .
'
~ :'
.` '. .``' ~.
.
~q :
O U E
~ ~ ~ t
hh ~ ~ ~ $~ ,1~ ~ .
~ ~ -.l E
,1 O O ~ O ~-.
O ~1 ~ 0
m ~
--1 8--
l~S~SC~
Example 4 shows utilization of a relatively high
intrinsic viscosity in the prepolymer. In this example some
depolymeri7ation was permitted in the second reactor prior to
the continuation of the condensation reaction. Example 5
shows utilization of a relatively high carboxyl prepolymer
with satisfactory results, however, in general a product with
lower diethylene glycol concentration can be produced using a
prepolymer having a lower carboxyl end group concentration. s
In Example 5, a relatively low molecular weight prepolymer was
employed for the addition of the sulfonate-containing monomer
followed by subsequent condensation in reactor 2. Example 6
illustrates the necessity for adequate mixing after addition
of the bis glycol ester of 5-sodium sulfo isophthalic acid.
In Example 6 the four inch diameter second reactor impeller,
w`hich had been rotated at 950 rpm in Example 5, was not in
motion. The polymer was not spinnable because of large
globules of additive in the polymer. Example 7 illustrates a
process in which no net polycondensation or depolymerization
takes place in reactor 2. ~xample 8 illustrates that a satis-
factory polymer can a~so be produced using the bis glycol
ester additive prepared b~ esterification of sodium sulfo
isophthalic acid as described in Example 2.
~XAMPLES 9~
In these examples, the equipment described in ~-
Example 3 was operated without using the second stirred-tank
reactor. The bis glycol ester solution was metered into either
reactor 1 or into the transfer line upstream of a 21 element
Kenics static mixer inst~lled between reactor 1 and the
column.
, ~
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TA9LE II ~
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ExampleExample ~xample
9 10 11
Reactor 1 Product
C~ ] 0.1000.071 ~.081
COOH, ~ eq/gm 586 536 430
DEG, wt. % - - 6.4
% Esterification 94 94 95
Injection rate of bis - ~
glycol ester of ~ -
sodium sulfo isophtha- -
lic acid, gm/min. 1.35 1.63 1.18
Ethylene glycol injected ;~
with bis glycol ester, ;
gm/min. 1.21 4.57 1.05
Molar ratio of EG to
total dicarboxylic ~-~
acids in column feed 1.2 1.8 1.7
:
PolYmer Product -
Flow rate, gm/min. Unreacted37.8 25.0
C~ ] bis glycol 0.54 0.58 `
COOH ~ eq/gm ester 22.3
DEG wt. % additive1.8 5.6 -
-SO ~a,~ eq/gm plugged - - ~ s-
Mel~ point, C column 244 214
Brightness 82 80
Purity 2.8 5.2
Chemstrand Whiteness 82 51
Example 9 illustrates the addition of a relatively
concentrated bis glycol ester solution to a prepolymer having
a relatively high molecular weight. This combination gave a ~ -
feed to the column having a molar ratio of total EG to total ~;?
dicarboxylic acids of only 1.2 and resulted in globules of
unreacted additive plugging the column. Example 10 illus-
trates the addition o~ a more dilute bis glycol ester solution
.
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to a prepolymer having a relatively low molecular weight.
This combination gave a molar ratio of total EG to total
dicarboxylic acids of 1.8 and resulted in a spinnable, homo- ~-
geneous polymer. Example 11 illustrates the addition of the
bis glycol additive into reactor 1. This resulted in a pre-
polymer having high DEG content and a spinnable, homogeneous
polymer having an undesirably low melting point and high DEG
content.
EXAMPLE 12
This example describes the preparation of a
cationic dyeable polyester via a batch terephthalic acid (TA)
process using an ethylene glycol (EG) solution of the bis
glycol ester of 5-sodium sulfo isophthalic acid.
A reactor was charged with 162 grams terephthalic
acid, 152 grams ethylene glycol, 0.10 grams of antimony
glycoloxide, 1.97 grams of an alkoxy polyoxyalkalene glycol
chain terminator having a general formula R-O[G-O]X-H where
R equals 14-15 and x equals 14, 0.02 grams pentacrythritol,
and 0.04 grams lithium acetate. The mixture was esterified
by heating ~or 90-minutes at a temperature of 240C during
which time water and ethylene glycol were continually removed. ~;
After completion o esterification 37.6 grams of a 24%
solution in ethylene glycol of the bis glycol ester of 5-
sodium sulfo isophthalic acid was added, the temperature ;
increased to remove excess ethylene glycol and polymerization
completed at,a temperature o 280C with a vacuum of less than
1 mm. The polymer obtained after 30 minutes polymerization
time had a speci~ic viscosity of 0.275, a DTA melting point
of 250C, and contained 0.65 weight percent diethylene glycol.
30 The polymer was spun and drawn 5.1 times to a yarn of excellent ~ ~
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- -21-
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whiteness. Microscopic examination revealed that no aggre- `
gates of the dye additive were present in the yarn. The ~
fiber dyed to a dark shade with Sevron Blue 2G (CI Name: -
Basic Blue 22); (no CI number) cationic dye. ~ ~
EXAMPLES 13 - 18 -
Two hundred gram portions of a prepolymer having an -~
intrinsic viscosity of 0.07, a carboxyl level of 535 ~eqjg, -~
containing 0.35 weight % of diethylene glycol, and having an -
EG/TA moiety ratio of 1.33/, were heated to a melt in 900
ml capacity autoclaves and ethylene glycol solutions of the
bis glycol ester of 5-sodium sulfo isophthalic acid added
prior to completion of polymerization. The following results
were obtained.
Grams Bis Resulting
Ex. Glycol Grams Temp. at EG/TA Results After
No Ester EG Addition Moiety Ratio Polymerizinq
13 9 28.6 230 1092/l ~o aggregation `~
Spun Well
14 9 10 240 1.54/1 Aggregated
~ot spinnable
9 10 260 1.54/1 Aggregated
~ot spinnable `
16` 9 22.5 240 1.79/1 No aggregation
Spun Well
17 9 16.3 240 1.66/1 ~o.aggregation
Spun Well
(1) 9 38 240 1.92/1 Aggregated ~ `~
Not spinnable
~l)In this Example the EG/TA moiety ratio was reduced from
1.38/1 to 1.15/1 by removal of additional EG under vacuum at
240C prior to addition of the EG solution of bis glycol ester.
At the time of reaction of the prepolymer with the bis glycol
ester of 5-sodium sùlfo isophthalic acid, the prepolymer had
an intrinsic viscosity of 0.10 and a carboxyl level of 243
eq/g-
-22- -~
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EXAMPLE 19
The composition described in example 12 was
prepared continuously in an 8 liter capacity reactor. The -
product from the reactor had an intrinsic viscosity of 0.081,
and a carboxyl level of 370~ eq/g. 200 grams of this reactor
product was heated to a melt in a 900 ml capacity autoclave
and 38 grams of a 20% solution of the bis glycol ester of 5-
sodium sulfo isophthalic acid in-ethylene glycol added and
polymerization completed. The polymer obtained was border-
line in spinnability due to the presence of particles in the
polymer melt.
EXAMPLE 20
Example 19 was repeated except that 15 ml of
ethylene glyco:L was added to the prepolymer and allowed to
equilibrate for 15 minutes before addition of the GSSIo The
addition of the ethylene glycol increased the EG~TA moiety
ratio above 1.35/1 and decreased the intrinsic viscosity.
3~ grams of a 20% solution of the bis glycol ester of 5-
sodium sulfo isophthalic acid was added to this adjusted pre-
polymer and polymerization completed. The resulting polymer
was free of aggregates and spun and drew normally. ;
EXAMPLE 21
This example is intended to show that materials
other than the bis glycol ester of 5-sodium sulfo isophthalic
acid can be added to the preformed prepolymer. A 900 ml
capacity autoclave was charged with 163 grams terephthalic
acid, 154 grams ethylene glycol, 0.1 grams of antimony
glycoloxide and 1.0 grams of lithium acetate dihydrate. ;~
Esterification to form low molecular prepolymer was performed
as in Example 3. This prepolymer had an ethylene glycoI-TA ~
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moiety ratio of 1.32/l. 1.97 Grams of the same chain ter-
minator as employed in Example 3 and 0.02 grams of penta-
erythritol were dissolved in 37.6 grams of a 24% solution of
the bis glycol ester of 5-sodium sulfo isophthalic acid. To
this solution was added 2.3 grams of a 30% slurry of titanium
dioxide in ethylene glycol and the resulting mixture slurried.
This slurry was added, at 240C, to the abo~e prepolymer and
polymerized completely as before.
The polymer obtained melted at 250 (DTA) and spun
and drew well. Microscopic examination showed it to be free
of aggregates and the titanium dioxide delustrant was well
dispersed throughout the yarn.
EXAMPLE 22
This example is intended to show that it is impera-
tive that the bis glycol ester of 5-sodium sulfo isophthalic
acid be added to the preformed prepolymer and not as part of `
the original charge. In the present example the bis glycol
ester, instead of being added to the prepolymer, was included
in the original charge to the reactor. Polymerization to
form a cationic dyeable polyester proceeded normally and no
.
aggregation of dye additive was present. The bis glycol
ester had entered into reaction with the terephthalic acid ;~
and ethylene glycol to ~orm a true copolymer. This method
of addition, however, was found to have one serious drawback.
Large quantities of diethylene glycol (greater than 7 mole
percent) were formed and yarn prepared melted at 214C (DTA). ;
This is a dramatic contrast with the 245-250C melting point
obtained when adding the bis glycol ester after prepolymer ~ ;'
formation.
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Tristimulus color was measured in a tristimulus
colorimeter, Kollmorgen Corp. (IDL~ large sphere color-eye.
Relative brightness is indicated directly by the value of Y.
Chromaticity coordinates x and y are calculated from the
reflectance measurements, as well known in the art of colori-
metry, and more particularly, as described at pages 9-10 of
the Massach~setts Institute of Technology Handbook of Colori-
metr~ ~1936 - The Technology Press, Massachusetts Institute
of Technology, Cambridge, Massachusetts). From the values x
and Yl purity (percent) and dominate wavelength (D~L in nm)
is determined from chart 12a in the above cited publication.
Chemstrand whiteness (Wc) is calculated using the following
equation:
W = 10 (y _ 2p2)1/2
where: Y = YCIE
p = purity
The number of dye sites actually present in the `~
filament, in terms of microequivalents per gram t-S03~a), may
be determined as follows. An accurately weighed polymer
20 sample of about 0.001 grams is placed in a 125 ml Erlenmeyer
flask fitted with a ground glass stopper. 25 ml of a melted
xylenol-chloroform is piped into the flask, and the sample
is refluxed on a water-cooled condenser until it dissolves in
about 15 minutes. The sample is then cooled to 40C or below
and 75 ml chloroform is added through the condenser. The
sample is then stirred and run through an ion exchange column
at a rate of about 8 ml/minute. The sample is then washed ~ ,
with about 300 ml chloroform at the same rate of elution. ;
The sample and washings are collected in a 500 ml flask. ~`
S drops of neutralized thymol blue indicator are added, and
-~5-
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the sample is ~itrated with a standard ethanolic KOH using a
1 ml microburet and magnetic stirring. Titration is to a
pure yellow color.
The polymer solvent is 2,6 dimethyl phenol (xylenol)
of which 500 grams is added to 85 ml of chloroform, the
solvent being melted in a water bath at about 60C just
prior to use.
The ethanolic KOH titrant is prepared by dissolving
14 grams of reagent grade (85%) potassium hydroxide in 1000 ~?
cc of absolute ethanol. It is standardized against potassium
hydrogen phthalate using phenolphthalein indicator, and pro- `
tected against atmospheric carbon dioxide.
~ y measuring specific viscosity (nsp) at 25C and
at a given concentration (1/2-4%) of the prepolymer in a
solvent having a molar ratio: 2 phenol/l trichlorophenol, ~
the intrinsic viscosity (~) is then calculated using the ;~ ;
relationship
~ = ( ~ ) [~ sp - 1 n~ rel] ~ rel = 1 + ~sp
As is well known in the art, the carboxyl end group concen-
tration can be determined by titration of the prepolymer withpotassium hydroxide. Ethylene glycol/dicarboxylic acid molar
ratios can be determined, as is well known in the art, by
. ~ :
material balance. -;
:.. : .
DEG is determined by gas chromatographic analysis
after saponification of the polymer or prepolymer. ~ ~ `
Melting points were determined from endotherms ~ `
obtained with a duPont Differential Thermal Analyzer.
The carboxyl concentration of 2000~ eq/g is roughly
equivalent to a percentage of esterification of about 78.
The theoretical lower limit on the intrinsic viscosity of the
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; ' ~
~5~S~ -
prepolymer which is suitable for the addition of the bis
glycol ester of the difunctional aromatic compound possessing
the sulfonate group is the intrinsic viscosity of a prepoly-
mer consisting entirely of monomer. Such a prepolymer would
not normally be obtained and the intrinsic viscosity would
not normally be less than about 0.05 with a degree of poly-
merization of about 2 to 6.
It must be appreciated that although the intrinsic
viscosity of the prepolymer should not exceed about 0.1
(or 0.07 as appropriate), an equivalent process may employ
a prepolymer of yet higher viscosity provided that subsequent
extreme depolymerization measures are taken so that depoly-
merization occurs to an intrinsic viscosity of 0.1 (or 0.07)
or below, in the presence of the difunctional aromatic com-
pound possessing the sulfonate group.
It is understood that changes and variations may -~
be made in the present inventions without departing from the ~`
spirit and scope thereof as defined in the appended claims.
,
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