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Патент USA US2411474

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Patented Nov. ‘19, 1946’
‘ 2,411,474
‘UNITED STATES2,411,474PATENT OFFICE
vMETHOD 0F IMPROVING FILAMEN TS 0F
HYDROLYZED
OLEFlN/YINYL
ns'rnn rN'rERroLYMERs
ORGANIC
Halsey B. Stevenson, Brandywine- Hundred, Del.,
assignor to E. I. du P
ont de Nemours & Com
pany, Wilmington, D_el.,'a
corporation of Dela
ware
No Drawing. Application October 18, 1944,
,
559,231
5 Claims. (Cl. .8—130.1)
Serial No.
‘This invention relates to improved hydrolyzed
resultant stretched ?lament in
and at a temperature within the‘range of v:from
ole?n/vinyl organic ester interpolymer, ?laments
and, more particularly,_ to a new process for im- I
proving the properties of ?laments derived from
102° C. to 104° C.
within the range of from 102° C. to'104°
hydrolyzed ole?n/vinyl organic ester interpoly- "
mers.
The following examples, in which proportions "
are in parts by weight unless
This invention has as an
of oriented ?laments of hydrolyzed ethylene/vinyl
otherwise: speci?ed,
10
I
,
‘
Ewample I
'
,
L
V
' An interpolymer oi’?ethylen-e and vinyl acetate
having a molar ratio oi‘ 2.6/1 of ethylene to vinyl
of ethylene at about 1000 atmospheres pressure .
and at about 65° C. to vinyl acetate containing
a small amount of benzoyl peroxide. The ethyl
ene/vinyl acetate interpolymer' was hydrolyzed
in a benzene-methanol solution with excess caus
tic and the interpolymer was isolated and the
a temperature within the range of from 80° C’. to
100° C. in a medium containing H2O a ?lament of
C.,
a substantially completely hydrolyzed interpoly
mer of ethylene with a vinyl ester of a mono
elongation and a
' carboxylic acid having the general formula
.
_
30
when immersed for 5 minutes
approximately 100° C.
RCOOH
drawn yarn was wound-on a metal
wherein R is of the
slight. tension and heat treated by
atoms and hydrocarbon radicals, said acid being
steam in an autoclave at 104° for 5v
DJ til
minutes,’ the yarn had a tenacity of 4.4' g./d. at
16% elong ,tion and had a shrinkage of only 8.5%
when immersed in boiling. water for‘ 5 minutes.
Example’ If
‘A'melt-spun' yarn of a substantially completely
40 hydrolyzed
ethylene/vinyl acetate interpolymer
having a molar ratio of ethylene-vinyl acetate of
2.8/1 was drawn in steam at 99-100° g. at a draw
ratio of 5.3/1 to give an oriented yarn having a
101°‘ C. to 106° 0., in a taut condition, with a
medium comprising H2O‘ at a temperature within 45 tenacity of\3.7‘ g./d. at 175% elongation and hav- "
the range of from 101° C‘. to 106° C.
ing a shrinkage of 27% whenvheated in water to
100° C. This yarn was heat
A preferred embodiment of this invention 'com
treated in steam for ‘
‘prises drawing, at a temperature within the range
about 5 minutes atl0l3°
" of from 90° C‘. to 100°
C. in steam at a tempera
ture‘within the range of from 90° (1110 100° 0., 50
v a ?lament of a substantially completely hydro-_
lyzed interpolymer of ethylene with vinyl acetate,
C‘.
When the above yarn was set at 100° C. in
steam under otherwise identical conditions, the
heat-set yarn had a tenacity of 3.7 g./d. at 20%
elongation but had a shrinkage of 13%
55 Jected to water at 100° C.
2,411,474 '
,
.
3
4
'
'
drolyzed ethylene/vinyl organic‘ ester interpoly
~
mer or by- spinning from a solution of the inter
Example III
_ A hydrolyzed ethylene/vinyl-acetate interpoly
mer of molar ratio of ethylene/vinyl acetate of
approximately 2.4/1 was dissolved in a trichloro
ethylene-ethanol mixture and ?laments obtained
polymer with ‘subsequent evaporation of the sol
vent. Suitable solvents are trichloroethylene
ethanolewater mixtures, primary aliphatic alcoe
hols boiling above 75°, primary and secondary
aliphatic amines and mixtures of aromatic hy
by “dry-spinning" the solution. The yarn was
drocarbons with such alcohols and amines.
oriented by drawing in steam at 99° C. at a draw
As hereinbefore stated, it is essential that the
ratio of 8.11/1 to give a yarn having a tenacity 10 ?lament should be drawn in a medium compris
of 3.9 g./d. at 12% elongation. The yarn was
ing water at a. temperature within the range of
\set in steam at 102° C. to give ?laments having
from 80° C. to 100° C. Furthermore, the time
a tenacity of 3.8 g./d. at 19% elongation. The
of travel of the ?lament through the drawing .
heat-set yarn had a shrinkage ‘of 12% when
medium must be such that said ?lament is heated
treated in water at ‘100° C. When the unset or 15 to a temperature within said range. While ap
which had not been subjected
preciable effects are obtained when'drawing is
untreated yarn
to the steam treatment was placed in boiling wa
effected at ‘a temperature as low as 80° C.,
ter, the yarn was so water-sensitive'that it broke.
markedly improved ?laments are produced when
The process of this invention is applicable to
the temperature of the aqueous medium and the
any ‘?lament of a hydrolyzed interpolymer of 20 filament during the drawing step is within the‘
ethylene with a vinyl ester of an organic acid
range of from 90° C. to 100° C. While the me
having the general formula RCOOH, wherein R
dium comprising H2O in which thedrawing .of
' is of the group consisting of hydrogen atoms and /
the ?lament is effected may be a bath of liquid
hydrocarbon radicals, said acid being free from
water, said drawing is carried out most readily
unsaturated linkages between acyclic'carbon at 25 and conveniently and with the production ‘of ?la
oms and any carbon atom alpha to the carbon
ment products having optimum properties when
atom in‘ the carboxyl group of said acid being
attached to at least one but not more than three
said medium comprises steam. The drawing or
orientation of the ?lament as described above is
therefore preferably carried out in steam, or
steam and air, at a temperature within the range
of from 90° Cfto 100°C. Drawing can be con
‘carbon atoms, provided the mol ratio of ethylene
- to vinyl/organic ester in said interpolymer prior
to hydrolysis was within the range of from 1/1
to 5/ 1. Included among examples of said inter
polymers are interpolymers of ethylene with vinyl
formate, with vinyl acetate,‘ with vinyl propi
onate, with vinyl butyrate, with vinyl stearate, 35
with vinyl benzoate, with vinyl cyclohexanoate,
with vinyl isobutyrate, with vinyl palmitate, with
vinyl myristate, with vinyl toluate, with vinyl '
naphthoate and thevlike. On account of supe
rior products had therewith, I prefer to employ 40
interpolymers of ethylene with a vinyl ester of
an‘ organic acid having the general
‘formula
_
CnH2n+1COOH, wherein n is a positive integer
within the range of from 1 to 3.‘ Inasmuch as
'
‘
the acid group of the vinyl ester is removed by 45
hydrolysis, it is usually most economical to use
veniently effected by passing the ?lament from
the snubbing roll‘ to the drawing roll through a
vertical tube open at both. ends and to which
steam‘ is admitted. By maintaining a speed dif-_ .
ferential betweenthe drawing roll and the snub
bing roll, the ?lament is stretched and oriented,
the tension on the drawing roll being su?icient'to
effect stretching but insufficient to cause break
_ By passing steam in the ver
ing of the ?lament. which
the ?lament is passed
tical tube through
during the drawing operation, it may be heated /
readily to the desired temperature. The use of
steam alone usually provides a temperature with
while tem
in the range ‘of from 99° C. to 100°C.C.,are
attained
peratures of from 80° C. to 99°
an interpolymer of- ethylene with vinyl acetate I by mixing air with, the steam before it is in
which is the most readily available vinyl ester.
troduced into the tube. Such- heating prevents
Appreciable effects are had when the mol ratio
local over-heating of the ?lament and avoids the
of ethylene to vinyl organic ester in the inter~
tendency to form broken ?laments. Less-pref’
polymer prior to hydrolysis is as low as 1/ 1, and 50 erable, although operable, is the employment of a
liquid water bath heated to a temperature‘ within '
also.when it isas high as 5/1. However, the ?la
ments obtained according to the process of this
the range of from 80° C. to 100° C. The use of
invention have markedly superior resistance to hot ' such baths necessitates guides for the filaments
water and substantially ‘improved dye receptivity '
and ‘these may bring about breakage of the ?la
of ethylene to vinyl organic 55 ments. Instead of baths of substantially pure
when the mol ratio
hydrolysis
is
liquid water, there may be employed baths of
ester in said interpolymer prior to
aqueous solutions, e. g., aqueous salt solutions
within the range of from 2/ 1 to 4/ 1.
Example I, interpolymeriza_ heated to ‘the desired temperature. However,
As indicated in
'
aqueous baths of substantially pure liquid water
tion of the vinyl ester with ethylene can‘ be car
ried out under super-atmospheric pressure in the to provide ?laments having higher tenacities than
are obtained through the employment of baths
of aqueous solutions; while highest tenacities are
drolyzed either in a lower aliphatic alcohol solu
obtained when the medium employed in the draw
tion or aromatic hydrocarbon-alcohol solution by \
ing operation 'is steam, either substantially‘pure
treatment with alkali hydroxide. For preparing 65 'or admixed with air. _ rawing temperatures
presence of a peroxygen-type polymerization cat
alyst. The resulting interpolvmei' may be hy
?laments the. resulting hydrolyzed interpolymer
,
above 100° C. cannot be used. Below 80° C., the
?lament is softened insuf?ciently for good draw
_
ably substantially completely hydrolyzed.
ing and lower
drawing ratios with lowertenaci-_.,
The‘ heat stability and water resistance of the 70 'ties (poorer ?nal properties) ‘are obtained.
should be-at least 80% hydrolyzed and prefer
?bers had in accordance with this invention are
_ In general the time of travel of'the ?lament
improved if the hydrolyzed ethylene/vinyl ester
through the‘ drawingmedium is 1 to 5 seconds,
although usually .1 to 3 seconds are preferred.
The time is related to ?lament size, drawing me
interpolymer is subjected to an extraction‘ with
hot methanol prior to formation of the‘?bers.
As shown in the examples, the ?laments may 75 dium and drawing temperature.‘ With regardto
' be obtained by either melt spinning of the hy
I
9,411,474
time of travel. the output or a drawing unit de- '
pends on the drawing speed and high‘ speeds may -
require longer tubes or baths for theheating.
It is to be understood that, duringthe drawing .
operation, any draw ratio short of the breaking.
point of the ?lament may be employed. How-'
ever. on account of the superior products thereby
obtained, I prefer to employ draw ratios ‘within
?xed length or under a slight‘ tension to prevent
shrinkage during the operation. In’ practice, it
is convenient to wind the ?lament on a'Iheat-re
sistant bobbin or similar member to maintain said
?lament at a ?xedlength during‘ the setting op
' oration.
The low shrinkage in ‘boiling water (5% to
the range of from 4.5/1 to 8.5/1, i. e. to draw the I 10%) 01' the ?laments obtained in accordance
?lament to a length within the range of'from 10 with this invention as compared to the‘ shrink‘
450% to 850% of its original length. _
~ ~
age of from 15% to 60% of hydrolyzed ethyl- '
Best results have been obtained by orienting or '
drawing of the ?lament which has ?rst been
brought into equilibrium with water at room tem
perature. Filaments containing less than about
carried out at elevated temperatures. The ?la
ments'as obtained by the process of this inven
tion have improved dye receptivity and increased
It seems probable that equilibrium of the ?lament ‘ elongation. ,Said ?laments are particularly use
with the water cannot be reached rapidly enough 20 ful in the production of fabrics such as hosiery.
?lter cloths, battery separators, tents and the
during the short time of passage 01' yam through
2-3% moisture draw more poorly in steam or wa
ter than ?laments which have been ?rst brought
into equilibrium withwater at room temperature.
the drawing medium.
-
like.
: ‘
After the ?lament has been drawn, and thereby
This setting is brought
'
ments of this invention may be made without de
' oriented, it must be set.
- about according to the .process of this invention
‘
As many apparently'widely different embodi
parting from the spirit and scope thereof, it is '
by contacting the drawn ?lament in taut condi
tion with a medium comprising H2O ata tem-,
perature within the range of from 101° C. to 106°
25 to be understood that I do not limit myseli_ to
C. Although the medium comprising H20 may
Having described the present invention, the
the speci?c embodiments thereof except as de
?ned in the appended claims.
'
'
I be liquid water at a temperature of from 101° C. 30 following is claimed as new and useful:
1,. The process for obtaining an improved hy
'to 106° 0., it is more convenient to use steam.
Furthermore, when said medium is steam, ?la
drolyzed ethylene/vinyl organic ester interpoly
moved from the steam bath it may be dried quick.
hydrocarbon radicals, said acid being free from ,
mer ?lament, which comprises drawing at a tem
ments having markedly superior properties re
perature within therange 01’ from 80° C. to 100°.
sult. The heat transfer from steam is better than
from liquid Water'and the ?lament‘ attains the 85 C. in a medium containing H2O at a temperature
within the range of from 80° C. to 100° C., a ?la
required temperature within the range of from
ment of a hydrolyzed interpolymer‘of ethylene
101° C.‘ to 106° C. more'rapidly and with better
with a vinyl ester of a monocarboxylic acid hav
control. Equipment adapted for treatment of
ing the-general formula RCOOH, wherein R is
the ?lament ,with steam,‘ e. g., an autoclave, is
readily available and..when the‘?lament is re 40 of the group consisting 01' hydrogen atoms and,
ly. It is preferred that the time of heat treat
ment in steam should not exceed 20 minutes since
heating times in” excess of 20 minutes result in
degradation of the ?laments. In general, opti
mum results are had when the?lament is cori
tacted with steam’ at from 102° C. to 104° C. for
a period of time within the range of from 5 min; ‘
utes to 20 minutes, although when the ?lament is
treated in the form of thick packages of yarn, 50
sumcient time must be allowed to obtain equilib
rium temperature throughout the package.
unsaturated linkages between acyclic carbon atoms
and any carbon atom alpha to the carbon atom
in the carboxyl group of said acid being attached
to at least one but not more than three carbon
atoms, the mo] ratio of ethylene to vinyl organic ;
ester in said interpolymer prior to hydrolysis hav
ing been Within the .range of from 1/1 to 5/1,
and thereafter heating the resultant [stretched
?lament at a temperature within the range of
from 101° C. to 106° C. in a taut condition in
contact with a, medium comprising H2O at a
temperature within the range 01’ from 101° C(to
,Setting temperatures in excess of 106° C. are
106° C.
- >
‘
to be avoided since such high temperatures usu
2.
The
process/for
obtaining
an
improved
hy
ally‘ cause some degradation of the ?lament with 55
idrolyzed ethylene/vinyl organic ester interpoly
resulting loss of "tenacity and other properties.
mer ?lament, which comprises drawing at a tem
On the other hand, when setting temperatures‘
perature within the range of from 90° C. to 100° C.
of less than 101° C. are employed, the resultant
?lament is not protected against subsequent]
in a medium comprising H2O at a temperature
shrinkage in boiling water. The subsequent tem 60 within the range of from 90°
ment of a hydrolyzed interpolymer of ethylene
perature employed within the heat-setting range
with a vinyl ester of a monocarboxylic acid hav
of from 101° C. to 106° C. may vary with the
particular hydrolyzed‘ interpolymer depending
ing the general formula CnHZn-i-ICOOH, wherein
n is a positive integer within the range of from 1
upon the molecular weight of said interpolymer
and the ratio of ethylene to vinyl organic ‘ester 65 to 3, the mol ratio of ethylene to vinyl organic
ester in said interpolymer prior to hydrolysis hav
originall'y'present in said interpolymer prior to
hydrolysis. The exact setting temperature for \ing been within the range of from 1/1 to 5/1,
and thereafter heating the resultant stretched
maximum properties of any given ?lament can
?lament at a temperature within" the range of
readily be determined. This determination may
be readily carried out by a few preliminary ex~ 70 from 101° C. to 106° C. in a taut condition in
contact with a medium comprising H20 at a tem
aerlnients to ?nd the optimum conditions.
perature within the range of from 101° C. to
The setting or heat treatment in the medium
106° C.
‘
:omprising H2O at a. temperature within the range
3. The process for obtaining an improved hy-I
)1’ from 101° C. to 106° 0. must be carried out
vith the ?lament in a taut condition, 1. e., at a 75 drolyzed ethylene/vinyl acetate interpolymer ?la
ment, which comprises drawing for a period of
2,411,474
7
the range of from 1/1 to 5/1, and thereafter con
from 1 to 5 seconds in a medium comprising steam
at a temperature within the range of from 90°
C. to 100° C., a ?lament of a‘ substantially com
tacting the resultant stretched ?lament in a taut
condition for a period of from 5 to 20 minutes
with steam at a temperature within the range of 7“
pletely hydrolyzed interpolymer of ethylene with
from 102° C. to 104° C.
vinyl,acetate,. the mol ratio of ethylene to vinyl
acetate in said interpolymer prior to hydrolysis
_
5. The'process for obtaining an improved hy
drolyzed; ethylene/vinyl acetate interpolymer ?la
having been within the range of from 1/1 to 5/1,
ment, which comprises drawing for a period of
and thereafter contacting the resultant stretched
from 1 to 5 seconds in steam at a temperature
?lament in a taut condition for a period of from 10 within the range of from 90° C. to 100° C., a ?la
5 to 20 minutes with amedium comprising steam
ment of a substantially completely hydrolyzed
at a temperature within the range of from 101°
interpolymer of ethylene‘ with vinyl acetate, the
mol ratio of ethylene to vinyl acetate in said
C. to 106° C.
4. The process for obtaining an improved by
interpolymer prior to ‘hydrolysis having been ‘with
drolyzed ethylene/vinyl acetate interpolymer ?la-
in the range of from 2/1 to 4/1, and thereafter
contacting the resultant stretched ?lament in a
taut condition for a period of from 5 to 20 min
utes with steam at a temperature within the range
ment, which comprises drawing for a period of
from 1 to 5 seconds in steam at a temperature
within the range of from 90° C. to 100° C., a ?la
ment of a substantially completely hydrolyzed
interpolymer of ethylene with vinyl acetate; the
' mol ratio of ethylene to vinyl acetate in said in
terpolymer prior to hydrolysis having been within
of from 102° C. to 104° C.
20
HALSEY B. STEVENSON. .
'
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