Note: Descriptions are shown in the official language in which they were submitted.
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PROCESS FOR PRODUCING ~DHESIVE
ACTIVE POLYESTER YARN
. _
BACKGROUND OF THE INVENTION
. _ _ . _
Field of the Invention
The present invention relates to a process
for producing adhesive active polyester yarn.
More particularly, the present invention relates to
a process for producing adhesive active polyester,
preferably polyethylene terephthalate, yarn wherein
the yarn is coated with an aqueous emulsion which
contains an epoxy silane, and after drawing, the
yarn is exposed to ultraviolet radiation. The
present invention also relates to the yarn produced
in accordance with the process. The yarn preferably
is twisted into tire cords for the construction of
pneumatic passenger tires and results in excellent
adhesion of tire cord to rubber.
DE$CRIPTION OF THE PRIOR ~RT
Polyester tire cord requires the application of
an adhesive layer to obtain bonding to the rubber.
Two types of adhesive systems, a single dip and a
double dip adhesive system, have been developed to
meet this need,
In the double dip system, polyester cor~s are
treated with a first dip which is a dispersion of a
phenol-blocked methylene bisphenylene diisocyanate,
an epoxy resin, wetting agents and water. The treated
?~,.
cord is cured, then treated with a second dip of
resorcinol-formaldehyde-latex and cured again.
In the single dip system, the adhesive layer
is applied to the polyester yarn in an overfinish
subsequent to drawing of the yarn. The polyester
yarn is plied into cords which are treated with a
resorcinol-formaldehyde latex dip and cured. The
need for the blocked diisocyanate dip in cord
processing is eliminated by this system. Low
carboxyl polyester yarn treated with this system
has very good ammonolytic and hydrolytic stability,
but has poor adhesion to rubber when made into
tire cord. Further, while regular carbox~l polyester
yarn shows acceptable adhesion to rubber under
normal curing temperatures, a reduction of the curing
temperatures has been found to adversely affect
adhesion to rubber.
The present invention significantly improves
yarn to rubber adhesion of polyester tire cords
treated with the single dip system for (a) low
carboxyl polyester yarn whersin normal curing
temperatures are utilized, and (b) regular carboxyl
polyeter yarn wherein reduced curing temperatures
are utilized
The closest pxior art is believed to be U.S.
Patents 3,642,518 to Miki et al., 3,672,977 to
Dardoufas, 3,730,892 to Marshall et al., and
4,054,634 to Marshall et al., and British Patent
Specification 1,228,173 to ~ervis et al.
SUMMARY OF THE INVENTI N
The present invention provides an improvement
in a process for the production of polyester yarn
involving spinning and drawing steps. The present
invention further provides polyester yarn treated in
accordance with the process.
J~
The improvement comprises: exposing the yarn
subsequent to the drawing step to ultraviolet
radiation; and treating the yarn with a finish
composition which comprises water and a silane
5 having the structural formula
CH3
H CH2 O(cH2)n~ OCH3
CH3
wherein n = 2 to 5
The step of exposing the yarn to ultraviolet radiation
may occur either prior to or subsequent to the
step of treating the yarn with the finlsh composition.
The ultraviolet radiation prefera-bly has
wave lengths between 200 and ~00 nanometers and a
peak wave length of about 253 nanometers. The time
period for exposure of the yarn to ultraviolet
radiation is at least about 0.3 second, preferably
about 0.3 to 7 seconds.
The finish composition may comprise about 50
to 98 weight percent o water and about 2 to 50
weight percent of the silane. When these form the
major finish composition ingredients and the finish
composition is to be applied by means of a
conventional lube roll~ it is pre~erred that a
small amount, for example 0 1 weight percent, of
a nonionic wetting agent be incorporated in order
to wet the lube roll; Triton X-100, Rohm & Haas
Company's trademark for polyoxyethylene 9-10 octyl-
phenol, is satisfactory.
It is preferred that the finish composition
be an overfinish composition which comprises an
oil-in-water emulsion wherein the non-a~ueous
portion comprises about 50 to 70 weight percent of
hexadecyl stearate, about 3 to 9 weight percent ~f
glycerol monooleate, about 2 to 8 weight percent of
4~?~
decaglycerol tetraoleate, about 5 to 12 weight
percent of ethoxylated tal~ oil fatty acid, about
5 to 15 weight percent of sulfonated glycerol
trioleate, about 1 to 10 weight percent of
ethoxylated al~yl amine, and about 2 to 45 weight
percent of the silane. The preferred silane is
gamma-glycidoxypropyltrimethoxysilane The yarn
is preferably treated with a sufficient amount of
the overfinish composition that (a) about 0.4 to
1.0 weight percent based on the weight of the yarn
of the non~a~ueous portion of the overfinish
composition is added, and (b) about 0.05 to 0.2
weight percent based on the weight of the yarn of
the silane is added. Alternatively, the overfinish
composition can comprise about 7 to 50 weight
percent of the silane, about 5 to 20 weight percent
of dimethyl polysiloxane emulsion, and the balance
water.
The present invention also provides, in a
process for the production of polyester yarn
involving spinning and drawing steps, the improvement
which comprises exposing the yarn subsequent to
the drawing step for a time period of at least about
0.3 second to ultraviolet radiation haviny a wave
lenyth between about 20a and 400 nanometers; and
treating the ~arn with an overfinish composition
comprisiny about 60 to 90 weight percent of water
and about 10 to 40 weight percent of an oil portion,
the oil portion comprising about 50 to 70 weight
percent of hexadecyl stearate, about 3 to 9 weight
percent of glycerol monooleate, about 2 to 8 weight
percent of decaglycerol tetraoleate, about 5 to
12 weight percent of ethoxylated tall oil fatty
acid, about 5 to 15 weight percent of sulfonated
glycerol trioleate, about 1 to 10 weight percent of
~5--
ethoxylated alkyl amine, and about 2 to 45 weight
percent of a silane having the structural formula
~H3
\2/ H CH2 0 (CH2) n-si--OCH3
0 OCH3
wherein n = 2 to 5~
Low carboxyl polyester yarn is defined as having
about 8 to 18 carbox~l end groups (meq./kg.~.
Regular carboxyl polyester yarn is defined as
having about 19 to 30 carboxyl end group~ (meq./kg.).
The strip adhesion test utilized in
illustrating the present invention is defined in
U.S. Patent 3,940,544 to Marshall et al.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In order to demonstrate the invention, the
following examples are given. They are provided
for illustrative purposes only and are not -to be
construed as limiting the scope of the invention,
which is defined by the appended claims. Specifi-
cally, it is believed that the finish composi-tion
can be applied either as a spin finish during spinning
or as an overfinish subsequent to drawing of the
yarn. Further, it is believed that there are other
spin finishes which would perform as satisfactorily
as the one detailed (see Table I). It is also
believed that there are other compatible non-aqueous
components which would perform as satisfactorily in
the overfinish composition as the ones detailed as
addi~ional to the silane. Xn these examples, parts
3Q and percentages are by weight unless specified
otherwise.
The yarns of this invention can be processed
by any spin draw process or spinning and separately
J~,;
~ 6~
drawing process available to the art and the patent
and technical literature, usin~ any suitable
polyester.
The preferred polyesters are the linear
terephthalate polyesters, i.e., pol~esters of a
glycol containing from 2 to 20 carbon atoms and
a dicarboxylic acid component containin~ at least
about 75 percerlt terephthalic acid. The remainder,
if any, of the dicarboxylic acid component ma~ be
lG any suitable dicarboxylic acid such as sebacic acid,
adipic acid, isophthalic acid, sulfonyl-4,4'-
dibenzoic acid, or 2,8-di-benzofuran-dicarboxylic
acid. The gl~col may contain more than two carbon
- atoms in the chain, e g~, diethylene glycol, butylene
glycol, decamethylene glycol, and bis-1,4-(hydroxy-
methyl)cyclohexane. Examples of linear terephthalate
polyesters which may be employed include poly(ethylene
terephthalate), poly(hut~lene terephthalate), poly
(ethylene terephthalate/5-chloroisophthalate) (85/15),
poly(ethylene terephthalate/5-~sodium sulfo]isophthalate)
~97/3), poly(cyclohexane-1,4-dimethylene terephthalate),
and poly(cyclohexane-1,4-dimethylene terephthalate/
hexahydroterephthalate? (75/25).
EXAMPLE` 1 ( COMPAR~TIVE )
For comparative testing, a polyethylene
terephthalate yarn haYing 11~1 carboxyl end groups
was prepared substantially in accordance with one
p~ocedure described in U,S. Patent 3,672,977 to Dardoufas,
i.e., a 1000 denier 192 filament yarn was prepared com-
prised of polyethy1ene terephthalate filaments treated
with about 0.45 percent based on the weight
of the yarn of a liquid spin finish identified
as spin finish A in Table I. Drawing performance of
the yarn was excellent. Finish oil on the fiber was
J~;
about 0.15 to 0.25 percent.
The ~arn was passed through a chamber enclosing
two 4-tube layers ~ith off~set centers of high
intensity lamps of the germicidal type having ~aYe
length of about 200 to 300 nanometers, with peak
wave length at 253 nanometers. The lamps were
approximately 83.8 centimeters (33 inches) in length
and can be obtained from the Ultradynamics
Corporation, Santa Monica, California. The yarn
made six passes throu~h the chamber, each pass
bein~ centered at a distance of about 1 centimeter
between three of the tubes so that high intensity
ultraviolet radiation fell on all sides of the yarn~
The lamps were found to provide maximum efficiency
at a temperature near 37.8C (100F.). The yarn
was exposed to the ultraviolet radiation for a total
of 7 seconds.
To this yarn a secondary finish, or overfinish,
identified as overfinish A of Table II, was applied
at a 3 percent total wet pickup to achieve a total
oil on yarn level of about 1 0 percent. The yarn
was then twisted into 3-ply cords having 9x9 twists
per inch. Each cord was treated with a conventional
non-ammoniated resorcinol-formaldehyde-latex dip
comprisin~ vinyl pyrridine latex, resorcinol,
formaldehyde, sodium hydroxide and water, at about
4.5 percent total solids pickup based on the weight
of the cord. The cords were then cured at treating
condition 3 of Table III. The treated cords were
subjected to the strip adhesion test, results of
which are presented in Table IV.
EXAMPLE 2 (COMPARATIVE)
The procedure of Example 1 was repeated Wit~
the following changes: The yarn was not exposed
to ultraviolet radiation; and the yarn was o~erfinished
at room temperature with overfinish ~ of Table II.
Results of adhesion testing a:re presented in
Table IV.
EXAMPLES ~3-5
The procedure of Example 1 was repeated in
each of Examples 3 throuyh 5 with the following
changes: The yarn was exposed to the ultraviolet
radiation for a period of 0.3, 3 and 7 seconds,
respectively, in Examples 3 through 5; and the
yarn was overfinished at room temperature with
overfinish B of Table II. Results of adhesion
testing are presented in Table IV.
EXAMPLES 6 and 7
The procedure of Example 1 was repeated with
the following changes: The yarn was not exposed to
ultraviolet radiation in Example 6 while in
Example 7, the yarn was exposed to ultraviolet
radiation for a period of three seconds; and in
both examples, the yarn was overfinished at room
temperatures wlth overfinish C of Table II. Results
of adhesion testing are presented in Table IV.
EX~MPLES 8-13
Polyethylene terephthalate ~arn having
24-1 carbox~l end groups was prepared in accordance
with the procedure of Example 1 in Examples 8 through
13, utilizing the spin finishes, overfinishes,
ultraviolet treatment and treating conditions specified
in Table IV. Results of adhesion testing are also
presented in Table IV.
EXAMPLES 14-19
Polyethylene terephthalate yarn having 24-1
carboxyl end groups was prepared in accordance with
the procedure of Example 1 in Examples 14 through
19, utilizing the spin finishes, overfinishes,
ultraviolet treatment and treating conditions
t 1L~; ~4~?~
specified in Table IY; however, the step of
exposing the yarn to ultraviolet radiation followed
the appllcation of overfinish to the yarn in
those examples (15, 16, 18 and 19) which included
both of these steps. Results of adhesion testing
are presented in Table IV.
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TABLE I
SPIN FINISH COMPOSITION (PERCENT BY WEIGHT)
Finish Identities
Components A B C D
__ _
Isohexadecyl stearate 15 - 30
Refined coconut oil 15 30
POE(4)* lauryl ether 13 13 13 10
Sodium salt of
alkylarylsulfonate 10 10 10 10
POE(20)* tallow amine 5 5 5 5
z Nekal WS-25** 2 2 2
Mineral oil 40 40 40 40
C8-C1O blended alcohol
ester of pentaerythritol - - - 30
Aerosol OT-S*** - - - 5
*Moles of ethylene oxide per mole of base material.
**GAF's trade name for solution consisting of 75 percent
sodium dinonyl sulfosuccinate, 10 percent isopropanol, and
15 percent water.
***American Cyanamid's trade name for solution consisting of
70 percent sodium dioctyl sulfosuccinate and 30 percent
petroleum distillate.
TABLE II
OVERFINISH COMPOSITIONS (PERCENT BY WEIGHT)
Finish Identities
Component A B C
Isohexadecyl stearate 19.5 18.7
Glycerol monooleate 1.8 1.7
Decaglycerol tetraoleate 1.5 1.4
POE(15)* tall oil fatty acid 2.4 2.3
Sulfonated glycerol trioleate 3.6 3.5
POE(20)* tallow amine 1.2 1.2
Gamma-glycidoxypropyl-
trimethoxysilane - 4.0 10
Water 70.0 67.2 80
Dimethyl polysiloxane emulsion** - - 10
*Moles of ethylene oxide per mole of base material.
**SWS 232, obtainable from SWS Corporation, Adrian, Michigan
49221.
rti
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TABLE III
SINGLE DIP* TREATING CONDITIONS
Drying Curing
Ternperature Exposure Temperature Exposure
Condition(C.) (F.) (seconds)(~C.) ~ (seconds)
1 149 300 80 204 400 60
2 149 300 80 218 425 60
3 149 300 80 241 465 60
*Non-ammoniated RFL dip at 4.0 to 5.0 percent total solids
pickup based on the weight of the cord, and 1 percent stretch.
1b~
TABLE IV
COOH UV Treating Adhesion**
End Spin Over- Treat- Con- Pounds Visual
Example Groups Finish finish ment ditions* Pull Rating
1 11-1 A A 7 sec. 3 22 2.5
2 11-1 A B no 3 24 3.0
3 11-1 A B 0.3 sec. 3 26 3.9
4 11-1 A B 3 sec. 3 26 4.3
11-1 A B 7 sec. 3 26 4.4
6 11-1 A C no 3 22 2.5
7 11-1 A C 3 sec. 3 25 4.5
8 24-1 A B no 1 24 3.0
9 24-1 A B 3 sec. 1 26 4.2
24-1 A B no 2 25 3.5
11 24-1 A B 3 sec. 2 29 4.4
12 24-1 A B no 3 26 4.6
13 24-1 A B 3 sec. 3 29 4.9
14 24-1 A B no 1 22 3.0
24-1 A B 1 sec. 1 22 4.2
16 24-1 A B 2 sec. 1 22 4.4
17 24-1 A B no 2 24 3.8
18 24-1 A B 1 sec. 2 22 4.3
19 24-1 A B 2 sec. 2 24 4.6
*See Table III
**Tested at 250F. (121C.).
~ -1 fi'~.J~;
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CONCLUS I(~NS
~ .
A comparison of Examples 1 through 7 shows
the critical importance to adhesion for low carboxyl
polyethylene terephthalate yarn of both exposing
the yarn to ultraviolet radiation and treating the
yarn with an aqueous finish composition containing
an epoxy silane as previously described. The
adhesion ratings were especially excellent for
Example 5.
A comparison of Examples 8 through 19 shows
the critical importan~e to adhesion for regular
carboxyl polyethylene terephthalate yarn of both
exposing the yarn to ultraviolet radiation and
treating the yarn with an aqueous finish composition
containing an epoxy silane as previously described.
n Examples 9, 11 and 13, the polyethylene
terephthalate yarn was exposed to ultraviolet
radiation prior to treatment with an aqueous
overfinish composition containing the epoxy silane,
while in Examples 15~ 16, 18 and 19, the polyeth~lene
terephthalate yarn was treated with an aqueous
overfinish compositi~n containing the epoxy silane
prior to exposure to ultraviolet radiation. The
adhesion ratirlgs were good in both instances. Further,
it can be seen that substantially lower curing
temperatures (treating conditions of Table III~ can
be utilized with the regular carboxyl yarn; this
results in both ener~y savings and reduced plant
emissions.
Alternative sources of ultraviolet radiation
can be used. For example, medium wave length
(280 to 400 nanometers) fluorescent sun lamp Model
FS-40 available from Westinghouse Corporation is
suitable. The intensity of ultraviolet radiation
is expressed in micro-watts per square centimeter
-15-
at a given distance. The total ultraviolet energy
emi,tted from all sides of the ultraviolet lamp is
expressed in watts. The total exposure is a product
of energy, time and area which is expressed as
ultrads (microwatt seconds per square centimeter).
The same number of ultrads can be achieved with a
short exposure time at a high intensity of
ultraviolet radiation, or a long exposure at a low
intensity of ultraviolet radiation, Exposures of
the polyethylene terephthalate yarn to ultrayiolet
radiation for a period of up to 15 minutes showed
virtually no loss of yarn breaking strength and
other yarn physical properties, but did show
improvement in adhesion to rubber when treated with
the overfinish system as described in this specification.
