MECHES

ROVINGS

Abrégé anglais

Abstract of the disclosure:
A roving having a cohesion length of 15 to 500 meters and
consisting of a strand of untwisted and unsized staple fibers.
having a total titer of from about 1,000 to 30,000 and, wrapped
around said strand, a filament yarn having an elongation at
break of less than 50 % and a titer of less than 15 dtex, the
number of windings being in the range of from 20 to 300 per meter,
has especially favorable properties when filaments of cross-
linked polyesters are used for wrapping.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED OR DEFINED AS FOLLOWS:

1. A roving having a cohesion length of 15 to 500
meters consisting of a non-consolidated strand of un-
twisted and unsized staple fibers, having a total titer
of from about 1,000 to 30,000 dtex and at least one
filament yarn wrapped around said strand, the yarn
having an elongation at break of less than 50% and
a titer of less than 50 dtex and being wrapped around
the strand from 20 to 300 times per meter, characterized
in that the filament comprises a crosslinked polyester
filament yarn.


2. A roving as claimed in claim 1, in which the filament
is a monofilament.


3. A roving as claimed in claim 1 in which the
polyester is polyethylene terephthalate, which contains
0.03 - 1.5 percent by weight of a crosslinking agent,
calculated on the pure polyethylene terephthalate.


4. A roving as claimed in claim 1, claim 2 or claim
3 in which the polyester is polyethylene terephthalate,
which contains 0.05 to 0.7 percent by weight of a
crosslinking agent, calculated on the pure polyethylene
terephthalate.


5. A roving as claimed in claim 1, claim 2 or claim

3 in which the polyester is crosslinked using at least
one compound of the group of esters and salts of compounds
of the general formula






Image


wherein x represents 1.5 or a number below 1.5 and
x may represent 0, wherein the ester groups are the
radicals of lower aliphatic alcohols having 1 to 4
carbon atoms and the salt groups are the ions of alkali
metals.


6. A roving as claimed in claim 1, claim 2 or claim
3 in which the polyester has been crosslinked with a com-
pound of the formula
(X2O)m(SiO2)n'

wherein X represents a hydrogen atom, a monovalent,
organic radical or an atom equivalent of a metal, n
represents an integer and m represents an integer
between O and 2n.


7. A roving as claimed in claim 1, claim 2 or claim
3 in which the polyester has been crosslinked with a
polyfunctional alcohol or a polyfunctional organic
acid.

Description

107~7~.~3

This invention relates to an improvement in the manufac_
ture of rovings by using filaments of cross-linked polyesters
for wrapping around the sliver of staple fibers.
In Copending Application Serial No.237 146 filed
October 6, 1975 by Fritjof Maag et al., a roving has been
proposed that consists of a sliver of staple fibers and at
least one filament yarn wound round the staple fibers. This
roving is distinguished by the fact that the staple fibers are
untwisted and unsized and have a total titer of approximately
~ 10 1000 to 30,000 dtex, preferably 2,500 to 15,000 dtex, and that
;;- the filament yarn has an elongation at break of less than 50%,preferably less than 25%, that the filament yarn has a titer of
less than 50 dtex, preferably less than 15 dtex, and that the
roving has a cohesion length of 15 to 500 m, preferably 30 to ~ ?
300 m, and that the number of windings is 20 to 300, preferably
30 to 100 per meter.
Surprisingl~, it has now been possible to ascertain
taht these rovings with their excellent properties are obtained
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in an especially advantageous manner by using as the filaments
that are wound round the staple fibers those produced from
crosslinked polyesters, monofilamenta preferably being used.




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Particularly favourable results are obtained if the polyester
is polyethylene terephthalate that contains up to 0.03 to
1.5 per cent by weight, preferably up to 1 per cent by weight,
especially up to 0.05 t~ c~ff~ y~i~wei~htiof'a crds~
linking agent calculated on the pure polyethylene terephthalate.
The polyesters preferably contain as crosslinking
agent silicon compounds, for example, of the formula

(X20)mtsio2)n~
in which X represents a hydrogen atom, a monovalent organic
radical or an atom equivalent of a metal, n represents an
integer and m an integer between 0 and 2n. These compounds,
and the method and manner in which t7~produce polyesters cross-
linked therewith, are described in German Auslegeschrift
12 37 727.
In another preferred embodiment, the polyesters
are obtained using esters and/or salts of compounds of the

~l general formula
'!'.~, O OH
,, 1~ 1
HO - P - CH2 - CH2 - Si - OH - xH2O,

'~ OH OH

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, in which x represents 1.5 or a number below 1.5 or even 0,
20 wherein the ester groups are ~he radicals of lower aliphatic
alcohols having 1 to 4 carbon atoms and the salt groups are
the ions of alkali metals. The manufacture and use of these
~ compounds are described in German Patent Specification No.

; 1 720 647. .

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107~;78S

Another possibility of crosslin~ing the polyesters
consists in using polyfunctional, purely organic compounds.
Suitable crosslinking components are, for example, pentaerythritol,
dipentaerythritol, glycerin, sorbitol, trimethylol ethane,
trimethylol propane, trimethylol butane, trimethylol hexane,
1,3,5-trimethylol beneze, 1,3,5-tripropylol benzene, 1,3,5-
tributylol benzene, 1,2,fi_hexantriol, 2,2,655_tetramethylol
cyclohexanol, hemimellitic acid, trimellitic acid, trimesic
acid, prehnitic acid, mellophannic acid, pyromellitic acid,

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mellitic acid and functional derivatives thereof, such as,
for example, methyl, ethyl and propyl or phenol esters. Also
suitable are 5~hydroxyisophthalic acid, 4_hydroxyisophthalic

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acid, 2,5-dihydroxyisophthalic acid, 2,5-dihydroxyphthalic
acid and functional deriva~ives thereof, such as, for example,
the esters with an aliphatic alcohol, such as methyl, ethyl and
propyl alcohols, or aromatic phenol esters. These permanent
- crosslinkers may also be used in admixture with the silicon

compounds which produce only a temporary crosslinking effect.
The winding filaments comprising crosslinked poly_ ;~
esters have to a great extent the properties that are required
... . .
;~ for the winding filaments described in the aforesaid specification:
they must impart to the sliver of untwisted staple fibers
sufficient strength for the processing, but must tear when
~- strained during the fine yarn production, i.e. they must not -
have too high an elongation. Filaments of crosslinked polyesters
' exhibit this combination of properties ideally. -
; Advantageously, in the case of small, colored slivers,
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1076785
non-matter winding filaments can be used.
The quantities both of the permanent and of the
temporary crosslinkers depend heavily on the number of
- functional groups contained therein.
As disclosed in applicant's copending Canadian
Application Serial No. 237,146, the staple fibers
consist of spinnable natural or man-made fibers and
may be selected from the group of wool, cotton, viscose,
polyester, polyamide, polyacrylonitrile, polyolefin
and polyurethane fibers.
The following examples serve to illustrate the
~; invention.
~ Examples
`~ The modified, crosslinked polyethylene tereph-
thalates were prepared in accordance with a discontinuous
:;.
process as follows:

Interchange of ester radicals:

Glycol and dimethyl terephthalate are introduced in the
' :!
ratio of 1 : 2.2 in~o a heatable pressure tank provided
with an agitator. The catalyst Mn-acetate and the
crosslinker are added at 140-150C.
The interchange of ester radicals is carried out
without pressure by heating up to 165-220C within a
period of 2.5 to 3 hours. The methanol released is
drawn off by way of a distillation column heated to
70-75C. Subsequently, at a tank temperature of 220C
and a column temperature of 195C, approximately




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1076785


2.0-2.5 1 of glycol is distilled off. The condensation
catalyst (antimony trioxide) and the sta~ilizer
(phosphorous acid) are then added.
Polycondensation:
The reaction solution at 225-230C is forced into
a condensation autoclave. There then follow, under nitrogen,
heating to 240C and the commencement of the evacuation
stage.




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After 105 minutes the complete vacuum of 0.1 mm Hg has been
reached, whilst the temperature is increased to 240-275C.
The viscosity of the melt is measured by resistance to stirring.
The condensation time is 2.5-3.5 hours. The removal of the
polymer melt is carried out under nitrogen.
~ le 1: Crosslinker according to German Patent 1 720 647
Polymer preparation:
0.03 percent by weight of manganese acetate . 4 H20 related to DMt
0.008 percent by weight of Sb203
0.4 percent by weight of TiO2
0.6 percent by weight SIP (silicon polyester) produced according
to German Patent l 720 647
`. specific viscosity: 0.535
softening point: 2B8.5C.
Spinning:
The polymer was spun from an extruder through a 2-hole
' nozzle with a hole diameter of 250 u, at a nozzle temperature
of 265C and a nozzle draw-off of 1800 m3min. The spun fila-
ments were wound onto a bobbin in the form of a monofilament
and stretched by a stretch-twisting machine (Zinser* 16 S model)
-~ in the ratio of l : 3.1 at a galette temperature of 90C and
an iron temperature of 120C.
;~ A monofilament with a strength of 34 g/tex and an
`~ elongation at break of 8% was obtained. The thread titer was
j appr~ximately 8 dtex. The monofilaments obtained were used,
- as in the above Specification for winding round a roving.
The results were rovings with the properties given therein.
* denotes trade mark


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~xample 2: Crosslinker: trimethylol propane
Polymer preparation:
0.03 percent by weight of manganese acetate . 4H20
0.015 percent by weight of phosphorus acid
0.03 percent by weight of antimony trioxide
0.4 percent by weight of TiO2
0.3 percent by weight of trimethylol propane
specific viscosity: 0.620
softening point: 257C.
Spinning:
The spinning was carried out analogously to that in
Example 1 at a nozzle temperature of 2qOC and a stretching
ratio of 1 : 3.65. The thread strength is 32 g/tex at an
elongation of 14% and an individual thread titer of 5 dtex.
Winding this monofilament round a roving in accordance
with the above Specification resulted in wound rovings having
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the advantageous properties quoted therein.
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: Example 3: Crosslinkers: pentaerythritol
.~ Polymer preparation:
20 0.02 per cent by weight of manganese acetate . 4H2O
`~` 0.01 percent by we;ght of phosphorous acid
0.03 percent by weight of antimony trioxide
:. 0.4 percent by weight of TiO2
0.2 percent by weight of pentaerythritol
specific viscosity: 0.61 ~:~
softening point: 258.5C.

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~pinning:
The spinning was carried out analogously to that in
Example 1 at a nozzle temperature of 270C and a stretching
~ ratio of 1 : 3.8. The thread strength is 34 g/tex at 20%
: elongation and an individual thread titer of 7 dtex.
The results of winding round a roving were as according
to the above Specification.

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