Note: Descriptions are shown in the official language in which they were submitted.
Z9~6787
- 1 - N 37551
Composition and process for preadherising
polyester filaments
The ;nvention relates to a compos;t;on of a poly-
epox;de and an amine for preadherising polyester fila-
ments w;th good adhes;ve propert;es towards rubber. The;nvention further relates to a process for preadher;sing
polyester filaments.
To improve the adhes;ve propert;es of synthetic
f;laments towards rubber ;t ;s conventional to treat them
with a composit;on which is a mixture of latex and resor-
cinol-formaldehyde res;n (an RFL bath). This conpos;tion
is then hardened on the filaments by means of a thermal
treatment.
~he presently frequently used filaments for rein-
forcing tyres, flexible tubes, V-belts and conveyor belts
are polyester filaments. The d;sadvantage in using poly-
ester filaments is that they have an insufficient number
of reactive end groups, so that the filamenttRFL bond is
poor. It is therefore necessary to subject the polyester
filaments to a pretreatment. Th;s pretreatment, also
referred to as preadherisat;on, is very often carr;ed out
by the fibre manufacturer himself, so that the consumer
can carry out the adherisation with RFL before vulcanising
the filament with rubber.
There are numerous existing processes for pread-
herising polyester. U.S. Patents 3,383,242 and 3,297,468,
- 2 ~ ~246787
for example, relate to a prosess for pretreatin0 poly-
ethylene terephthalate filaments by applying to said
fi~aments (A) a dispersion of a hardenable combination of
a diepoxide and a diamine having primary or sccondary
functions (harden;ng agent) and (O) a ~ater-dispersible
filament finish. This application takes place onto an
undra~n filament, ~hich is ~ound up and subsequently con-
ventionally stretched in a second operation. The disad-
vantage of this process is that it is necessary to use a
composition ~hich solidifies into a gellike mass after a
fe~ hours at room temperature. The stability of the
solution is thus poor. In addition, the filament cannot
be drawn using heated rollers, but can only be dra~n in
ovens, i.e. even at slo~ take-off speeds. Excess pread-
herising solution would harden on the rollers and ~ouldquickly build up into a crust. Moreover, the filaments
tre-ated in this process have impaired mechanical
properties.
In U.S. Patent 3,962,011 nylon cord yarns, i.e.
already plied yarns, are impregnated ~ith a comb;nation
of a polyepoxide and a tertiary amine and the combination
is thermally hardened.
U.S. Patent 3,793,425 and German Offenlegungs-
schrift 2,056,707 relate to an integrated sp;n-stretch
process for producing polyester filament yarns by apply-
ing a composition containing a polyepox;de res;n buffered
at alkal;ne pH to the freshly spun and l;ke~;se st;ll
~`` lZ9L~787
un6tretched polyester filament, and then hot-~tretching and
winding-up the filament thus treated.
The present invention provides a composition for
S preadherising polyester filaments which contains a polyepoxide
and a tertiary amine, a~ well as a process for preadherising
polyester filaments ~y applying the composition according to the
invention to the ~tretched filament.
The invention therefore relates to a process for
preadherising polye~ter filaments to ameliorate their adhesive
properties towards rubber, wherein the polyester filaments after
stretching are treated with a composition consisting of a
: polyepoxide and a tertiary amine having the following general
; formula
~Rl
X (CH2) ~ \ (I)
\ R2
where 1~ n~ 6, R1 and R2, are identical or different, each alkyl
having C1_~, hydroxyalkyl having C1_6, alkylaryl or aryl, and X
i~ H, OH, NH2, NH3, NR~R5 or R6, where R3, R~, R, and R6 are
each al~yl having C1_6 or aryl groups.
The invention further relates to a composition of a
polyepoxide and an amine for preadherising polyester filaments,
which i6 characterised in that the amine is a tertiary amine
having the following general formula:
`:
~C
~- ~29L~787
- 3a -
X ~CHZ)~ - N / (I)
\ R2
where 1~ n ~ 6, Rl and R2, identical or different, are each alkyl
having C1-61 hydroxyalkyl having Cl_6, alkylaryl or aryl, and X
i5 H, OH, NH2, NHR3, NR~R5 or R6, where R3, R4, Rs and R6 are
each alkyl having C1-6 or aryl groups.
This composition is more stable than tha~ described in
U.S. Patents 3,383,242 and 3,297,468. Compound (I) is an amine
having at least one tertiary function. It is assumed that the
tertiary amine has a catalytic action on the reaction between the
polyepoxide and the polymer. The group X can also be a primary,
secondary or
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tertiarj amine. ~n that case the second am;ne function
;ncreases the catalyt;c activ;ty. By v;rtue of compound
(I) an adhes;ve layer is formed and, alone or together
w;th an RFL treatment, confers good adhes;on to the fila-
ment on vulcanisation into rubber.
Compound (I) is preferably N,N-dimethylbenzyl-
am;ne~ 3-diethylamino-1-propylam;ne, 3-dimethylamino-1-
propylamine, tribenzylamine, triethanolamine or triethyl-
am;ne. The type of polyepoxide in the composition
according to the invention is not critical. The speci-
fically preferred type is that of the glycidyl ethers
which are generally prepared by reacting epichlorohydr;n
with an alkanol or a phenol. The polyepox;de can be
saturated, unsaturated, aliphatic, cycloaliphatic, aro-
matic, heterocyclic or substituted. The compounds aree;ther monomers or polymers having at least two epoxy
groups per molecule.
Examples of such compounds are the epoxy deriva-
t;ves of bisphenol A or of phthalic acid, the epoxyphenol
novolac, the epoxycresol novolac, the glycidyl isocyanur-
ates, the epoxy-containing derivatives of hydantoin, such
as hydantoin triglycidyl ether, the aliphatic glycidyl
ethers, such as butanediol diglycidyl ether, ethylene-
glycol diglycidyl ether or glycerol triglycidyl ether,
and the glycidyl der;vatives of triaz;ne, such as tris-
t2,3-epoxypropoxy)-3-propionyl-1,3,5-hexahydro-s-triaz;ne
(TEPS).
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- 5 ~
Because the abovementioned TEPS is read;ly sol-
uble in water it was already used ;n the compos;t;on des-
c;ibed ;n U.S. Patent 4,121,901. The composition accord-
;ng to the ;nvent;on is ;n solut;on ;n water, alcohol,
a water-alcohol mixture or a f;bre finish. For the pur-
poses of th;s ;nvent;on a f;bre f;nish ;s ch;efly a pro-
duct wh;ch ;mproves the fr;ctionaL, antistatic and wet-
t;ng propert;es of the synthet;c f;lament.
This composition can be used either on its own or
together ~;th aux;l;ar;es. For the purposes of th;s
invention auxiliaries are products which are capable of
;mprov;ng st;lL further the adhes;on of the f;lament to
rubber, for example carr;er or swell;ng agents, such as
ethylene glycol, caprolactam or polyvinyl or benzyl alco-
hol, or solvents which permit more efficient d;ffus;on ofthe epoxide into the polymer. Wetting agents or surface-
active agents, such as the commercial products QZ 13 from
CI3A-GEIGY and TW 1196*from ZSCHIMMER ~ SCHWARZ, which
are solutions w;th s;licones or ethoxylated compounds,
can also be used. Secondary preadherising agents can
also be applied ;n add;t;on, for example those based on
silanes tepoxysilanes), polychlorophenols tVulcabond E*
from VULNAX) or those hav;ng free or blocked ;socyanate
groups, or urethanes, poly;m;nes, polyacrylates and poly-
am;des. It ;s likew;se possible to subject the filamentpreadherised according to the invention to a treatment
r~ w;th the conventional pretreatment agent compris;ng a
. 1 * Trade Mark
~Z4 Ei787
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polyepox;de and a blocked poly;socyanate before the RFL
treatment.
The amount of polyepoxide ;n the composition
according to the invention is 5 to 99% by weight and that
of compound ~I) is 0.01 to 6.0, preferably 0.05 to 3, X
by weight. The remainder comprises wat~r, alcohol,
water-alcohol mixture or fibre finish.
The invention further relates to a process for
preadherising polyester filaments which is characterised
in that the abovementioned composition of polyepoxide and
tertiary amine is applied to the stretched filament. In
this process, unlike in the process descr;bed ;n U.S.
Patent 3,793,425 and German Offenlegungsschrift Z,û56,707,
the stretch rollers do not become encrusted, and the
filaments have good mechanical properties.
The type of polyepoxide and of compound (I) is
the same as in the composition accord;ng to the inven-
tion, as is the nature of the solut;on.
The amount of polyepox;de and espec;ally of com-
pound (I) appl;ed to the filament is fa;rly critical,according to the invention. As regards the polyepoxide,
a level below O.O5X g;ves r;se to the problems of ;nade-
quate adhesion and irregular distribution of the poly-
epoxide along the filament, and a level greater than O.SX
does not give better adhesion. Compound (I) gives maxi-
mum adhesion of the filament to the rubber when applied
in an amount of 2 to 300 ppm, preferably 5 to 100 ppm.
~%4~i787
All the abovement;oned levels of polyepoxide and eompound
(I) are relative to the treated polyester filament.
For the purposes of the present invention poly-
esters are linear polycondensed esters prepared by react-
ing one or more diols of the HO(CH2)nOH series ~here
1 ~ n C 10 ~ith a dicarboxylic acid, preferably tere-
phthal;c acid, or a corresponding diester, such as dime-
thyl terephthalate. The polyesters can also be modified
uith organic or inorganic additives. The polyester used
for reinforcing elastomers has been or;ented and
stretched in order to obtain reinforcing filaments hav-
ing satisfactory mechan;cal properties for their use.
The preferred polyester is polyethylene tere-
phthalate without restriction as regards the terminal
carboxyl group or diethylene glycol content.
The stretched filament is produced in an integ-
rated spin-stretch process in which the filament is ~ound
up at take-up speeds of 2,000 to 6,000 m/m;n. The com-
position according to the invention ;s applied by means
of one or t~o metering PinS between the final duo and the
~inding apparatus or subsequently during the rebind;ng of
the stretched filament.
It may be necessary to do further treatments on the
stretched filament in order to improve its running perfor-
2S mance or fatigue level, for example by applying polysiloxanes,silanes, polyethylene glycols or ester or mineral oils.
The process according to the invention makes it
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possible to produce a polyester filament having very good
mechan;ca~ properties and an ;mproved adhcsion to rub-
ber. This process is also very simple and very econom;-
cal, since the stretching is not adversely affected. The
linear density of the polyester filament yarn thus pro-
duced is not critical. It 1s preferably between 500 and
2,50û dtex, and the number of individuaL filaments is
between 8û and SûO. This filament yarn is particularly
suitable for reinforcing rubber articles, such as car
tyres, conveyor belts, V-belts and flexible tubes. It
can also be used for articles which are coated with
polyvinyl chloride.
The filament yarn thus obta;ned is then ready for
a conventional treatment with an RFL bath prior to the
vulcanisation with rubber. For certa;n uses it is even
vulcanised into the rubber without RFL impregnation.
The filament yarn preadherised according to the
invention can also be subjected to a secondary treatment
in a conventional polyepoxide bath mixed w;th an aqueous
dispersion~of a blocked poly;socyanate before it is imp-
regnated with the RfL and/or vulcanised into the rubber.
The invention finally relates to the polyester
f;lament yarns thus produced w;thout restriction as
regards the terminal carboxyl group content. It is of
course also possible to apply the composition to the un-
stretched filaments separately from or together with the
spin finish in a separate spinning and stretching process
~2~787
_ 9 _
or in a spin-stretch process.
The polyepox;de, ~hich ;s advantageously soluble
in uater, is dissolved in a concentration of 5 to 99X in
a presubmitted amount of water, water-ethanol m;xture or
solvent, such às polyglycols, ben2yl alcohol or ester
o;ls. Afterwards, but before the composition ;s used,
compound ~I) is added in a concentrat;on of 0.01 to 6.0,
preferably 0.05 to 3.0, X by we;ght.
Production of cord yarn
A polyester filament yarn hav;ng a linear density
of 1,100 dtex and comprising 192 high-modu~us, high-
strength monofilaments ;s produced as follows using a
spin-strech process:
The highly viscous polymer is melted at a tempe-
rature of 280 to 330C in an extruder, and the melt isextruded through a sp;nneret. After cooling down in an
quenching stag the filaments are drawn off at normal
speed and are guided over a fin;sh application roller,
where a sp;n finish is applied, and over a plurality of
pairs of rollers which are operated at different tempera-
tures and speeds, where the filaments are stretched and
heat-set. Depending on the desired mechanical yarn pro-
perties the rollers can have temperatures between 70 and
245C. The roller speeds are such that the spun f;~a-
ments can be stretched up to six times their originallength. The filaments are directly wound up at a take-
up speed of 3,000 m/min.
- 12~787
- lo -
A number of these filament yarns, for example 2,
are t~isted together in conventional manner to form a
gr age cord yarn. This yarn is then impregnated on
a treatment machine ~;th an RFL solution consist;ng of
20X of a resorc;nol-formaldehyde resin and of a latex and
is then thermally treated ;n convent;onal manner at 150C
for 30 seconds and then at 235C for 1 minute. This
;mpregnated cord ;s then vulcanised ;nto the rubber.
The adhesive properties of the cord vulcanised
into the rubber are tested using UNIROYAL's A-300 strip
test, in ~hich the variable measured is the force ~hich
is necessary to separate t~o layers of rubber from a cord
fabric vulcanised into the rubber. A pull force of less
than 10 daN ind;cates poor adhesion, and a pull force
greater than 15 or 20 daN indicates good to very good
adhes;on to the rubber.
The appearance value indicates ho~ ~ell the rub-
ber adheres to the cord layer. The highest value of S
characterises an adhesive bond ~here the crack appears in
2û the rubber and no cord is visible at the crack surface.
The poorest value of O characterises an adhesive bond
~here the crack takes place at the rubber-cord ;nterface,
so that no rubber remains stuck to the cord layer. The
values from 0.5 to 4.5 are ;ntermed;ate levels. In the
present case the cord has a pull force of 7 daN and an
appearance value of 0.
` ` 12~787
- 11 -
Examples 1 to 11
The yarn ;s produced ;n accordance w;th the
invention as mentioned above, except that the f;laments
are guided at a po;nt between the f;nal duo and w;nd;ng
apparatus over a preadher;s;ng dev;ce ;n the form of a
meter;ng pin ~here the compos;tion ;s appl;ed.
The compos;t;on cons;sts of a polyepox;de~ a ter-
t;ary am;ne and a solvent. The concentration of the poly-
epox;de ;n our examples ;s 35X by we;ght, wh;le that of
the tert;ary am;ne accord;ng to the ;nvent;on ;s given in
the table~ The level on the fibre ;n the examples ;s
0.2X of epoxy resin. The yarn thus produced ;s ;mpreg-
nated w;th RFL and then vulcan;sed ;nto the rubber.
The table below shows the str;p test results
obtained on apply;ng d;fferent compos;t;ons.
Example 1 shows how poor the adhes;on ;s ~hen the
compos;t;on does not conta;n compound ~I) accord;ng to
the ;nvent;on ;n add;t;on to the polyepox;de.
In Examples 2 to 4 the catalyt;c effect of the
tert;ary amine accord;ng to the ;nvent;on comes ;nto
play. Example 3 represents an opt;mal am;ne concentra-
t;on at wh;ch the pull force value ;s at a max;mum.
In Example 5 only 0.05X of polyepox;de, and not
0.2X, were appl;ed to the yarn. The pull force ;s lower,
although ;t ;s still h;gher than ;n Example 1, where the
polyepox;de level ;s four t;mes as h;gh but no compound
(I) ;s present.
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Examples 6 to 10 l;kew;se form part of the
subject-matter of our invent;on. As can be seen, the
nature of the polyepoxide tdiepox;de or tr;epoxide having
different structures) is of not ins;gnificant ;mportance)
~Examples 6 and 8). The solvent, by contrast, is not
cr;tical (Examples 8 and 9). In Examples 7, 8 and 10
different am;nes are used together with the same epoxide.
In Example 11, the polymer used and ethylene
ox;de are added before be;ng melted in the extruder. The
resulting f;~ament only has a term;nal carboxyl group
content of 5 mol/t. The f;lament yarn produced ;n accor-
dance w;th the invention as regards its compos;t;on and
the process used ;n mak;ng ;t has fa;rly good adhes;ve
propert;es. The adhes;ve properties are only ins;gn;fi-
cantly worse than those ;n Example 8, where the yarn con-
ta;ns a term;nal carboxyl group content of 20 mol/t.
The f;laments of Examples 2 to 11, wh;ch were
obtained ;n accordance w;th the ;nvention, are d;st;n-
gu;shed by good process;ng properties, for example the
absence of depos;ts at the twist;ng stage. Although the
;ndividual filaments are treated, the fatigue level of
the tyre cord produced is not ;mpa;red.
~ 12~6787
- 1 3
T~ble
~r-pl-~olyepolide Solvent j~o~pound ~1) StriP t st
I ,,
lSEPS ~1 ll2 none lO l 0
_ _ _
2~ ~ O S ~ DPA ~9~16 0 3 0
3~ ~ l 0 ~ ~ 20 5 3 5
2 0 ~ ~ l8 0 3 5
5~ ~ 1 0 ~ ~ 16 0 3 0
6BD W (b) ~ O S t DMD ~fl l~ 0 3 0
7 GSG ~e) ~ I 0 t DMPA le~ l6 3 3 0 - 3 5
8 ~ ~ O S ~ DMB If ~ lô 0 3 5
9 ~ R20/ethanol 2 l0 5 ~ ~ 19 0 3 0 - 3 5
0 6 t TEA Id~ 20 0 3 5
ll ~ 1l20 5 ~ DMB lf~ 15.0 1.0
~-) TEPS - tris(2,3-epo~ypropoly)-3- Id) SEA - triethrnolrn1ne
propionyl-1,3,5-he~hydro- ~e~ DMPA ~ 3-dinethyl~eino-1-
s-tr1e21ne propyl~ine
Ib) BDDG - butrnediol diglycidyl ether ~f ) DMB - di~ethylben2ylanine
Ic~ GTG - 91ycerol triglyc1dyl ether 191 DPA r 3-diethyl~ ino-1-
