FORMABLE, HEAT-STABILIZABLE OPEN NETWORK STRUCTURE

STRUCTURE A MAILLES OUVERTES DEFORMABLE POUVANT ETRE STABILISEE PAR TRAITEMENT THERMIQUE

English Abstract

The present invention relates to an open network structu-
re interlooped or interlaced from a multifilament hybrid
yarn composed of at least 2 varieties A and B of fila-
ments with or without cofilaments C, wherein said fila-
ments A are textured and have a melting point above
180°C, preferably above 220°C, in particular above 250°C,
said filaments B have a melting point below 220°C,
preferably below 200°C, in particular below 180°C, the
melting point of said filaments B being at least 20°C,
preferably at least 40°C, in particular at least 80°C,
below the melting point of said filaments A, and the
weight ratio of said filaments A:B being within the range
from 20:80 to 80:20, preferably from 40:60 to 60:40, and
the multifilament hybrid yarn additionally containing up
to 40% by weight of cofilaments C, said open network
structure possessing good flatness and a capability to be
rolled up and to be three-dimensionally deformed.
The network structure of the present invention can be
used in various ways for the decorative styling of
complicatedly shaped surfaces, in particular for the
production of light and vision protectors having a
specifically predetermined light transmissivity and as an
air-permeable insect resistor material.

Claims

- 20 -
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An open network structure interlooped or interlaced
from a multifilament hybrid yarn composed of at least
2 varieties A and B of filaments with or without
cofilaments C, wherein
said filaments A
are textured and have a melting point above 180°C,
preferably above 220° C, in particular above 250°C,
said filaments B
have a melting point below 220°C, preferably below
200°C, in particular below 180°C,
the melting point of said filaments B being at least
20°C, preferably at least 40°C, in particular at
least 80°C, below the melting point of said filaments
A, and the weight ratio of said filaments A:B being
within the range from 20:80 to 80:20, preferably from
40:60 to 60:40, and the multifilament hybrid yarn
additionally containing up to 40% by weight of
cofilaments C.
2. The open network structure of claim 1, characterized
by good flatness and a capability to be rolled up and
to be three-dimensionally deformed.
3. The open network structure of at least one of claims
1 and 2, wherein said higher melting textured
filaments A have a crimp of 3 to 50%, preferably of
8 to 30%, in particular of 10 to 22%.
4. The open network structure of at least one of claims
1 to 3, wherein said higher melting textured
filaments A are air jet textured or preferably false
twist textured.
5. The open network structure of at least one of claims
1 to 4, characterized by a capability to be
consolidated by a heat treatment.

- 21 -
6. The open network structure of at least one of claims
1 to 5, wherein said filaments A have a melting point
of above 220°C, preferably of 220 to 300°C, in
particular of 240-280°C.
7. The open network structure of at least one of claims
1 to 6, wherein said filaments B have a melting point
of below 220°C, preferably of 100 to 200°C.
8. The open network structure of at least one of claims
1 to 7, wherein there exists bundle coherency between
said filaments A and B and any C.
9. The open network structure of at least one of claims
1 to 8, wherein said multifilament hybrid yarn
contains no cofilaments C.
10. The open network structure of at least one of claims
1 to 9, wherein said multifilament hybrid yarn has a
linear density of 80 to 500 dtex, preferably 100 to
400 dtex, in particular 160 to 320 dtex, said higher
melting textured filaments A have a linear density of
0.5 to 15 dtex, preferably of 2 to 10 dtex, and said
lower melting filaments B have a linear density of 1
to 20 dtex, preferably of 3 to 15 dtex.
11. The open network structure of at least one of claims
1 to 10, wherein said higher melting textured
filaments A are dyed, preferably spun-dyed.
12. The open network structure of at least one of claims
1 to 11, having a basis weight of 50 to 250 g/m2,
preferably of 75 to 200 g/m2, in particular of 85 to
150 g/m2.
13. The open network structure of at least one of claims
1 to 12, having 1 to 250, preferably 10 to 200,
openings per cm2.

- 22 -
14. The open network structure of at least one of claims
1 to 13, comprising a flat or relief-structured knit
or weave.
15. The open network structure of at least one of claims
1 to 14, comprising a flat plain knit.
16. The open network structure of at least one of claims
1 to 14, comprising a knit with a pronounced relief
effect.
17. The open network structure of at least one of claims
1 to 14, comprising a patterned, structured inter-
looped material with tuck or knob stitch.
18. The open network structure of at least one of claims
1 to 14, comprising a warp-knitted net with fringe
and inlay.
19. The open network structure of at least one of claims
1 to 14, comprising a tulle construction.
20. The open network structure of at least one of claims
1 to 14, comprising a flat weave.
21. The open network structure of at least one of claims
1 to 14, comprising a leno weave.
22. The open network structure of at least one of claims
1 to 14, comprising a weave with a marquisette
structure.
23. The open network structure of at least one of claims
1 to 14, comprising a weave with a pronounced relief
effect.
24. The open network structure of at least one of claims
1 to 14, comprising a weave with a piquet structure.

- 23 -
25. The open network structure of at least one of claims
1 to 24, wherein said higher melting textured
filaments A are polyester filaments and said lower
melting filaments B are composed of a modified
polyester having a reduced melting point.
26. The open network structure of at least one of claims
1 to 25, wherein the polyester contains at least
70 mol%, based on the totality of all polyester
structural units, of structural units derived from
aromatic dicarboxylic acids and from aliphatic diols,
and not more than 30 mol%, based on the totality of
all polyester structural units, of dicarboxylic acid
units which differ from the aromatic dicarboxylic
acid units which form the predominant proportion of
the dicarboxylic acid units or are derived from
araliphatic dicarboxylic acids having one or more,
preferably one or two, fused or unfused aromatic
nuclei, or from cyclic or from aliphatic dicarboxylic
acids having in total 4 to 12 carbon atoms,
preferably 6 to 10 carbon atoms, and diol units
derived from branched and/or longer-chain diols
having 3 to 10, preferably 3 to 6, carbon atoms or
from cyclic diols, or from diols which contain ether
groups or, if present in a minor amount, from poly-
glycol having a molecular weight of about 500-2000.
27. The open network structure of at least one of claims
1 to 26, wherein the polyester, based on the totality
of all polyester structural units, is composed of
35 to 50 mol% of units of the formula -CO-A1-CO- (I)
0 to 15 mol% of units of the formula -CO-A2-CO- (II)
35 to 50 mol% of units of the formula -O-D1-O- (III)
0 to 15 mol% of units of the formula -O-D2-O- (IV)
and
0 to 25 mol% of units of the formula -O-A3-CO- (V)
where

- 24 -
A1 denotes aromatic radicals having 5 to 12, prefer-
ably 6 to 10, carbon atoms,
A2 denotes aromatic radicals other than A1 or arali-
phatic radicals having 5 to 16, preferably 6 to
12, carbon atoms or aliphatic radicals having 2
to 10 carbon atoms, preferably 4 to 8 carbon
atoms,
A3 denotes aromatic radicals having 5 to 12, prefer-
ably 6 to 10, carbon atoms,
D1 denotes alkylene or polymethylene groups having
2 to 4 carbon atoms or cycloalkane or dimethyl-
enecycloalkane groups having 6 to 10 carbon
atoms,
D2 denotes non-D1 alkylene or polymethylene groups
having 3 to 4 carbon atoms or cycloalkane or
dimethylenecycloalkane groups having 6 to 10
carbon atoms or straight-chain or branched
alkanediyl groups having 4 to 16, preferably 4 to
8, carbon atoms, or radicals of the formula
-(C2H4-O)m-C2H4-, where m is an integer from 1 to
40, m = 1 or 2 being preferred for proportions up
to 20 mol% and groups having m = 10 to 40 being
preferably present only in proportions of below
5 mol%,
the proportions of the basic units I and III and
of the modifying units II, IV and V being
selected within the framework of the above-speci-
fied ranges so that the polyester has the desired
melting point.
28. The open network structure of at least one of claims
1 to 27, wherein the yarns consist of polyesters
which contain cocondensed in the chain units of the
formula VI
<IMG> (VI)

- 25 -
where R is alkylene or polymethylene having 2 to 6
carbon atoms or phenyl and R1 is alkyl having 1 to 6
carbon atoms, aryl or aralkyl.
29. A process for producing a network structure to be
thermally consolidated by weaving or knitting a flat
or relief-patterned weave or knit, which comprises
feeding the weaving or knitting machine with a yarn
which is at least 30%, preferably at least 75%, a
multifilament hybrid yarn consisting of at least 2
varieties A and B of filaments with or without
cofilaments C, wherein
said filaments A
are textured and have a melting point above 180°C,
preferably above 220°C, in particular above 250°C,
said filaments B
have a melting point below 240°C, preferably below
220°C, in particular below 200°C,
the melting point of said filaments B being at least
20°C, preferably at least 40°C, in particular at
least 80°C, below the melting point of said filaments
A, and the weight ratio of said filaments A:B being
within the range from 20:80 to 80:20, preferably from
40:60 to 60:40, and the multifilament hybrid yarn
additionally containing up to 40% by weight of
cofilaments C.
30. The process of claim 29, wherein the network
structure obtained is subjected to a consolidating
heat treatment at a temperature at which the lower
melting filaments soften.
31. The process of at least one of claims 29 and 30,
wherein the heat treatment is carried out at 130 to
220°C, preferably at 150 to 200°C.
32. The process of at least one of claims 29 to 31,
wherein the raw state material of the network struc-
ture weave or knit produced is heat-set on a tenter.

- 26 -
33. The process of at least one of claims 29 to 32,
wherein said filaments B of said multifilament hybrid
yarn used are flat.
34. The use of the network structure of claim 1 for
producing light and vision protectors.
35. The use of the network structure of claim 1 for
producing air-permeable insect resistors.

Description

217223 ~
HOECH8T TREVIRA GMBH & CO RG HOE 95/T 004 Dr. RD
Formable, heat-~tabilizable open network ~tructure
DeQcription
The present invention relate~ to a formable, heat-stabi-
lizable open network ~tructure compo~ea of a multifila-
ment hybrid yarn compo~ed of at lea~t 2 varieties A and
B of filament~ with or without cofilament~ C, said open
network Qtructure po~e~ing good flatne~ and a cApabi-
lity to be rolled up and to be three-dimensionally
deformed.
The sheetlike network material of the present invention
can be used in various way~ for the decorative styling of
complicatedly shaped surface~, in particular for the
production of light and vision protectorQ having a
specifically predetermined light transmissivity and a_ an
a ir-permeable insect re~istor material.
CloQed sheet materialQ composed of hybrid yarn~ compo~ed
of lower melting and higher melting fiber materials and
con-Qolidatable by heat treatment are already known. For
in~tance, EP-B-0359436 disclo~e~ louvre blind~ where the
louvre strip~ are of a fabric compri~ing lower melting
and higher melting yarn~, ~aid fabric, once produced,
being ~ubjected to a heat treatment which cau~e~ the
lower melting yarn component~ to melt and ~tiffen the
fabric.
It i8 al~o known to use hybrid yarn~ having a high-
melting or unmeltable filament content and a
thermoplastic lower melting filament content to produce
~heet material~ which, by heating to above the melting
point of the thermoplastic, lower melting yarn component,
can be converted into fiber-reinforced, stiff
thermoplastic sheets, a kind of organic sheet-metal.

217223S
- 2 -
Various way~ of producing a fiber-reinforced
thermoplastic ~heet stock are described in
Chemiefa~ern/Textiltechnik Volume 39/91 (1989) pages T185
to T187, T224 to T228 and T236 to T240. The production
starting from ~heetlike textile material~ composed of
hybrid yarns is described there as an elegant way, which
offers the advantage that the mixing ratio of reinforcing
and matrix fiber~ can be very precisely controlled and
that the drapability of textile material~ makes it ea~y
to place them in press mold~ ~Chemiefa~ern/Textiltechnik
Volume 39/91 (1989), page T186).
A~ revealed on page T238/T239 of this publication,
however, problem~ arise when the textile material~ are to
be deformed in two dimensions. 8ince the exten~ibility of
the reinforcing threads is generally negligible, textile
sheet~ compo~ed of conventional hybrid yarn~ can only be
deformed becau~e of their textile con~truction.
However, this deformability generally has narrow limit~
if crea~ing i~ to be avoided ~T239), an experience that
wa~ confirmed by computer simulations.
Hybrid yarns composed of unmeltable ~e.g. glass or carbon
fiber) and meltable fiber~ (e.g. polyester fiber) are
known. For in~tance, J~p~ne~e publication JP-A-04 353 525
concerns hybrid yarn~ composed of nonmeltable fibers, for
example glas~ fiber~, and thermopla~tic, for example
polye~ter, fiber~.
8imilarly, EP-A-551 832 and DE-A-29 20 513 concern
combination yarn~ which, although ultimately bonded, are
first present a~ hybrid yarn.
EP-A-0 444 637 discloses a proces~ for producing a
crimped hybrid yarn from lower melting and higher melting
filament yarns. In thi~ proces~, first the higher melting
yarn is crimped in a texturing jet ~a bulking jet a~
described in US-A-3 525 134), then it i~ combined with
the lower melting yarn, and the two yarn~ are jointly
crimped in a second texturing jet.

217223~
It i8 an object of the present invention to provide an
open network ~tructure which possesse~ good flatnes~ and
a capability to be rolled up and to be three-dimen~ional-
ly deformed and can be used for the crease-free decorati-
ve ~tyling of complicatedly ~haped ~urfAce~, in particu-
lar for the production of light and vision protector
element~ having a specifically predetermined light
tran~mi~sivity and a~ An air-permeable in~ect re~i~tor
material.
Thi~ object i~ achieved by the hereinafter described
network ~tructure of the pre~ent invention.
The present invention provide~ an open network structure
interlooped or interlaced from a multifilament hybrid
yarn composed of at lea~t 2 varieties A and B of
filament~ with or without cofilaments C, wherein
said filament~ A
are textured ~nd have a melting point above 180C,
preferably above 220C, in particular above 250C,
~aid filAment~ B
have a melting point below 220C, preferably below
200OC, in particular below 180C,
the melting point of said filament~ B being at lea~t
20C, preferably at lea~t 40C, in particular at least
80OC, below the melting point of said filament~ A, and
the weight ratio of ~aid filament~ A:B being within the
range from 20:80 to 80:20, preferably from 40:60 to
60:40, and the multifilament hybrid yarn additionally
containing up to 40% by weight of cofilament~ C.
An essential advantage of thi~ network ~tructure i~ that
it possesses good flatnes~ and a capability to be rolled
up And to be three-dimen~ionally deformed.
Thi~ u~eful property i~ particularly favored And even
achieved when it con~i~t~ of a weave if the higher
melting textured filament~ A have a crimp of 3 to 50%,
preferably of 8 to 30%, in particular of 10 to 22%.

~7273'i
- 4 -
The crimping of the higher melting filaments can in
principle be effected by all known methods in which a
two- or three-dimensional crimp i~ set into the filament~
at elevated temperature. guitable known proce~e~ are for
example stuffer box crimping, gear crimping, the knit-de-
knit proce~, wherein a yarn i~ fir~t knitted up into a
ho~e, heat-~et in that form and then unravelled again.
The preferred proces~ for texturing the filament~ A,
however, i~ the fAlse twi~t proce~ de~cribed in numerou~
publication~. AdvantAgeou~ly, higher melting textured
filAment~ A ~re air jet textured or preferably fal~e
twi~t textured.
A further particularly useful property of the network
structure of the present invention is that it can be
con-~olidated by a heat treatment. In the course of the
heat treatment, the lower melting filament~ B of the
multifilament hybrid yarn of the network structure form
at least to ~ome extent a matrix which interconnect~ the
higher melting textured filament~ of the multifilament
hybrid yarn. A~ a re~ult of the interconnection of the
filAmentq A by the matrix, the cooling down of the
network ~tructure of the pre~ent invention i~ accompanied
by the consolidation and, depending on the inten~ity,
i.e. the temperature and duration, of the heat treatment
by a ~pecific stiffening of the material.
A matrix for the purposes of this invention is a continu-
ou~ polye~ter ma~ formed by the complete or partial
melting of the filaments B or by A mutual adhering of the
filaments B softened to the point of tackiness.
To obtain thi~ possibility of consolidation without
allowing unde~irable losse~ in respect to ~trength,
dimensional ~tability of the material under severe-duty
condition~, it i~ convenient and advantageou~ for the
filament~ A to have a melting point of above 220C,
preferably of 220 to 300C, in particular of 240-280C.

217223~
It i8 further convenient and advantageous for the fila-
ments B to have a melting point of below 220C, prefer-
ably of from 100 to 200OC, in particular of 130 to 190C.
The melting point of the matrix yarn is adapted to the
intended use of the network structure of this invention
within the stated limits. Adaptation is by making the
matrix yarn from a polymer material having the right
melting point. For instance, a network structure of thi~
invention thAt is exclu~ively intended for USQ ~t room
temperature may advantageously include filaments B having
a melting point within the range from 100 to 120C, for
example of about 110C, while network structure of this
invention that are to be exposed to very high tempera-
tures, as may arise for example as a result of intensive
sunlight in confined spaces, comprise bonding filaments
B having a melting point within the range from 160 to
180C. In most cases, network structures according to
thi~ invention that comprise filaments B having a melting
point within the range from 130 to 150C will be appro-
priate.
It is thus essential for the present invention to usefilament varieties A, B satisfying certain melting point
targets.
The melting point of the filaments is determined on the
polymer raw material used for making them. A special
feature of many polymer materials, including, for
example, polyester materials, is that they generally
soften before melting and the melting process extends
over a relatively large temperature range. It is nonethe-
les~ possible to determine readily reproducible tempera-
ture points which are characteristic of these polymer
materials, for example polyester materials, at which the
sample under investigation loses its geometric shape,
i.e. passes into a liquid (albeit frequently highly
viscous) ~t~te. The determination of these characteristic
temperature points is effected using so-called penetro-
meters (analogously to DIN 51579 and 51580), where a

~172236
- 6 -
measuring tip of defined dimension is placed under
defined pressure onto a chip or pellet of the polymer
sample to be investigated, the sample is then heated up
at a defined heating-up rate, and the penetration of the
measuring tip into the polymer material is monitored and
measured.
As soon as the sample, for example the polyester sample,
softens, the measuring tip begins to penetrate very
slowly into the material.
The penetration of the mea~uring tip can slow down again
at increasing temperature and even cease completely, if
the ~oftened, initially amorphous, polyester mass crys-
tallize~.
In this case, a further increase in the temperature will
reveal a second softening range which then turns into the
below-described "melting range".
Said "melting range" is a certain fairly narrow tempera-
ture range characteristic of the material, in which a
pronounced acceleration of the penetration of the measur-
ing tip into the polyester material takes place. Atemperature point can then be defined as a readily repro-
ducible melting point when the measuring tip has reached
a certain penetration.
A melting point for the purposes of th;s invention is
that temperature point (average of 5 measurement~) at
which a measuring tip with a circular contact area of
1 mm2 and a contact weight of 0.5 g has penetrated
1000 ~m into a polymer sample, for example a polyester
~ample, heated up at 5C/min.
Not only for reason~ specific to the production but also
for reasons of a particularly advantageous distribution
of the matrix material in the course of the consolidation
(short flow paths), it is preferable for good bundle
coherency to exist between the filaments A and B and any
C.
Bundle coherency between the filaments is necessary to
form a thread structure which can be processed in the
manner of a yarn, i.e. which can be woven or knitted, for

;~17223~
- 7 -
example, without individual filaments of the assembly
coming out of the assembly or forming major loops and
thus leading to disruptions of the processing step~.
The required bundle coherency can be brought about for
example by imparting to the yarn a so-called protective
twist of, for example, 10 to 100 turns/m or by spot-
welding the filament~ together. Preferably, the required
bundle coherency i~ brought about by interlacing in a jet
in which the filaments to be cohered together into a yarn
are blasted from the side by A fAst-moving jet of gA~
while passing through a narrow yarn passageway. The
degree of interlacing and hence the degree of bundle
coherency can be varied by varying the force of the ga~
jet.
Preferably, the filaments A, B and any C of the multi-
filament hybrid yarn are interlaced, the degree of inter-
lacing of the multifilament hybrid yarn advantageously
corresponding to an entanglement spacing of 10 to 100 mm.
The degree of interlacing is characterized in term~ of
the entanglement spacing measured with an ITEMAT needle
tester in accordance with the needle test method
de~cribed in US-A-2 985 995.
Further preferred features of the multifilament hybrid
yarn, which according to the application requirement~ or
for convenience may be present individually or in varying
combination~, are that the filaments B are flat, that the
multifilament hybrid yarn contain~ no cofilaments C, that
it has a linear density of 80 to 500 dtex, preferably 100
to 400 dtex, in particular 160 to 320 dtex, that the
higher melting textured filament~ A have a filament
linear density of 0.5 to 15 dtex, preferably of 2 to
10 dtex, and that the lower melting filaments B have A
filament linear density of 1 to 20 dtex, preferably of 3
to 15 dtex.
In the intere~t~ of good wear on the part of the network

~17223~
- 8 -
structure of the present invention, it is advantageous to
use a multifilament hybrid yarn whose higher melting
textured filaments A have an initial modulus of 15 to
28 N/tex, preferably of 20 to 25 N/tex, and a tenacity of
above 25 cN/tex, preferably of above 30 cN/tex, in
particular of 30 to 40 cN/tex.
Depending on the field of use of the network structure of
the present invention, it i8 preferable that the higher
melting textured filaments A be dyed, preferably spun-
dyed.
The lower melting filaments B can be spun-dyed or
preferably ecru, since it has been found that, on thermal
consolidation of the network structure of the present
invention, the material of the filament B is very sub-
stantially taken up by the strands of the filaments A,conferring in total the dark color of the filaments A.
It has been found that, in the making of the network
structure of the present invention, other yarns can be
used as well as the multifilament hybrid yarn to be used
according to the present invention. Advantageously,
however, the proportion of the multifilament hybrid yarn
should be at least 30%, preferably at least 75%, in
particular 100%.
For most applications it is advantageous for the basis
weight of the network structure of the present invention
to be 50 to 250 g/m2, preferably 75 to 200 g/m2, in
particular 80 to 150 g/m2.
The number of the openings depends on the intended use of
the network structures of the present invention and, in
accordance with the widely differing areas of use, can be
varied within wide limits. Depending on the application,
1 to 250 openings/cm2 are advantageous. Preference i~
generally given to network structures that have 10 to 200
openings per cm2, with the most frequent applications
requiring opening numbers within the range from 25 to
180, in particular from 40 to 140.

2172236
The interlaced or interlooped constructions are chosen
according to the u~e intended for the network structure
of the present invention, not only ~ccording to purely
technical criteria but additionally a l~o from decorative
a~pect~.
Depending on the intended u~e, the network ~tructure of
the present invention comprises a flat or relief-struc-
tured knit or we~ve.
An interlaced network ~tructure according to the pre~ent
invention can be knitted with synchronous or consecutive
course formation and be pre~ent a~ ~ingle jer~ey or
double jer~ey in all their variants, provided only that
the setting~ shall correspond to the above-indicated
~titch denqity.
For example, a network structure knitted with ~ynchronou~
courqe formation can be warp-knitted or weft-knitted, in
which case the con~truction~ can be widely varied by
mean~ of loop~ or floats (cf. DIN 62050 and 62056).
A knitted network -qtructure can have a rib, purl or plain
con~truction and their known variant~ and al~o Jacqu~rd
patterningq.
Rib construction also comprehend~ for example it~
variantq of plated, openwork, ribbed, shogged, wave,
tuckwork or knob and also the interlock construction of
one x one rib cros~ed.
Purl construction also comprehend~ for example it~
variants of plated, openwork, interrupted, ~hogged,
tran~lated, tuckwork or knob.
Plain con~truction also comprehends for example it~
variant~ of plated, floating, openwork, plush, inlay,
tuckwork or knob.
Of course, it i~ al~o poqsible for Jacquard patterning~
of appropriate ~titch density to be present.
Further interesting embodiment~ for the network
qtructure~ of the present invention are warp-knitted
marquisette or filet constructions. For network
~tructures which ~hall be relatively inelastic and form-
stable even prior to the heat treatment it i~ al~o

2172236
-- 10 --
possible to u~e warp knits with inlay or weft-knitted
double jersey constructions a~ well aQ the below-de~-
cribed wovens.
The knitted ~tructure~ preferred for flat network
~tructure~ are the basic construction~ rib, purl or
plain, in particular plain.
Con~truction~ which are very highly ~uitable for the
practice of the pre~ent invention, in particular in the
wide-me~h range, are the naturAlly non-Qlip tulle
con~tructionQ, for example bobinet tulle, which can be
present in the stated density a~ grid, twist or honeycomb
tulle.
For certain purpo~e~ it iQ preferable to have network
~tructure~ having a pronounced relief structure. 8uch
network structure~ have for example an enhanced screening
effect in relation to obliquely incident insolation
compared with completely flat net~ having the same free,
open area.
In the~e ca~e~, it i8 preferable for the network
~tructure of the pre~ent invention to comprise a knit
having a pronounced relief effect, for example a
patterned, ~tructured knit having a tuck or knob
con~truction, a Jacquard-patterned material, or a warp-
knitted net with fringe and inlay.
The figure~ 1 and 2 illustrate, at about 1.4-fold magni-
fication, arc ~ector portions of a heat-stabilized, flat
plain knit (1) according to the present invention and of
a structured 1:1 tuck pique knit ~2). It i5 evident that
the interlooped ~tructure doe3 not come undone at the cut
edges.
As likewise already indicated above, a further embodiment
of the network ~tructure of the present invention i~
woven. In principle, A woven network ~tructure may have
any known weave conQtruction ~uch as plain weave or it~

~1~223~
11
derivative~, for example rib, basket, huckabaek or moek
leno, or twill and it~ many derivative~, of which only
herringbone twill, flat twill, braid twill, lattice
twill, cros~ twill, peak twill, zigzag twill, shadow
twill or Qhadow eros~ twill will be mentioned a8
example~. ~For the weave eonstruetion deQignation~ ef.
DIN 61101).
The weave eonstruetion preferred for flat network
~trueture~ is the plain weave with or without ~imple
derivative~ without major float~.
It i~ advantageou~ to eonstruct woven~ in the ~t~ted
den~ity in leno eon~truction ~half, plain or full leno)
in order to eonfer ~ufficient ~lip re~i~tance on the
material for the further treatment (thermostabilization,
making up)O
In a very advantageou~ embodiment of the pre~ent
invention, the network structure compri~es a leno weave
or ~pecifieally a marqui~ette material.
A~ ~lready mentioned above, network ~trueture~ having a
pronouneed relief ~tructure are preferred for certain
purpo~es, for example for use a~ vision and light
proteetors. Woven network strueture~ aecording to the
pre~ent invention meet the requirement of ~ relief-
structured Qurface when they consist for example of a
weave with a pique structure. In this construetion, the
ten~ioned ~titehing warp insure~ ~ relieflike deformation
of the ~urfaee.
As observed above, the network strueture of the pre~ent
invention is constructed from a multifilament hybrid yarn
comprising higher melting ~A) and lower melting filament~
(B), subjeet to the provisos that the melting point~ are
a certain, technically dictated minimum distance apart
and that filament~ A are textured. These features ~re
neeessary, but also sufficient, in order to impart the
ability to deform and the eapacity for thermoeon~olida-

2172236
tion.
The filaments A of the multifilament hybrid yarn are
subject to the reguirement that they melt above 180C,
preferably above 220C, in particular above 250C. In
principle they may consist of all spinnable materials
meeting these requirements. 8uitable are therefore not
only natural polymer materials, for example filaments of
regenerated cellulose or cellulose acetate, but also
synthetic polymer filaments, which, because their mechan-
ical and chemical properties are widely variable, areparticularly preferred.
For instance, in principle, filaments A can consist of
high performance polymers, such as, for example, polymers
which, without or with only minimal drawing poqsibly
after a heat treatment following the spinning operation,
yield filaments having a very high initial modulus and a
very high breaking strength ~= tenacity). Such filaments
are described in detail in Ullmann's Encyclopedia of
Industrial Chemistry, 5th edition ~1989), Volume A13,
pages 1 to 21 and also Volume 21, pages 449 to 456. They
consist for example of liquid-crystalline polyesters
~LCP), polybenzimidazole ~PBI), polyetherketone ~PEK),
polyetheretherketone ~PEEK), polyetherimides ~PEI),
polyether sulfone ~PESU), aramids such as
poly~m-phenyleneisophthalamide) ~PMIA), poly~m-phenylene-
terephthalamide) ~PMTA) or poly~phenylene qulfide) ~PPS).
Advantageously, therefore, the filament~ A consist of
regenerated or modified cellulose, higher melting poly-
amides ~PA), for example 6-PA or 6,6-PA, polyvinyl
alcohol, polyacrylonitrile, modacrylic polymers,
polycarbonate, but in particular polyesters. Polyesters
re suitable in particular therefore for use as raw
material for the filaments A because it is possible, in
a relatively simple manner, through modification of the
polyester chain, to vary the chemical, mechanical and
other physical application-relevant properties, in
particular, for example, the melting point.

2 l~l2236
- 13 -
Suitable polymer materials for the lower melting fila-
ment~ (B) likewise advantageou~ly include spinnable
polymers, for example vinyl polymer~ ~ueh as polyolefins,
sueh as polyethylene or polypropylene, polybutene, lower
melting polyamides, for example 11-PA, or Alicyelie
polyamide~ ~for example the product obtainable by eonden-
sation of 4,~'-diaminodicyclohexylmethane and decaneearb-
oxylie aeid), but in partieular here too modified
polye~ters having a redueed melting point.
A~ explained earlier, it i8 partieularly advantageous for
the higher melting textured filaments A to be polye~ter
filament~ and it i~ then partieularly advantageou~ for
also the lower melting filaments B to consist of modified
polyester having a reduced melting point.
If all the yarn eonstituents of the multifilament hybrid
yarn consist essentially of the same polymer cla~s,
appreciable advantages result with respect to the di~-
posal of the used material. This is because such a
~ingle-material product is particularly ~imple to
recycle, for example by ~imple melting and regranul~tion.
If the polymer material of the multifilament hybrid yarn
i~ essentially polyester, it is additionally possible to
reeover useful raw materials from the used produet~, for
example by aleoholysis, for produeing virgin polyester~.
Polyesters for the purpose~ of this invention also
inelude copolyesters construeted from more than one
variety of dicarboxylic acid radical and/or more than one
variety of diol radical.
A polyester from which the fiber material of the network
structure of the present invention are made eontains at
lea~t 70 mol%, based on the totality of all polyester
structural units, of structural units derived from
aromatie diearboxylie aeid~ and from aliphatie diols, and
not more than 30 mol%, based on the totality of all
polyester struetural unit~, of diearboxylie aeid unit~

217~6
which differ from the aromatic dicarboxylic acid unit~
which form the predominant proportion of the dicarboxylic
acid units or are derived from araliphatic dicarboxylic
acidQ having one or more, preferably one or two, fu~ed or
5 unfu~ed Aromatic nuclei, or from aliphatic dicarboxylic
acid~ having in total 4 to 12 carbon atom~, preferably 6
to 10 carbon atom~, and diol unitQ derived from branched
and/or longer-chain diols having 3 to 10, preferably 3 to
6, carbon atom~ or from cyclic diol~, or from diol~ which
10 contain ether group~ or, if present in a minor Amount,
from polyglycol having a molecular weight of about 500-
2000.
8pecifically, the polyester, based on the totality of all
polye~ter structural unit~, i8 composed of
35 to 50 mol% of units of the formula -CO-A1-CO- ~I)
0 to 15 mol% of unitQ of the formula -CO-A2-CO- (II)
35 to 50 mol% of unit~ of the formula -O-D1-O- ~III)
0 to 15 mol% of unit~ of the formula -o-D2-o- (IV)
~nd
0 to 25 mol% of unit~ of the formula -o-A3-co- (V)
where
A1 denote~ aromatic radical~ having .~ to 12, prefer-
ably 6 to 10, carbon atom~,
A2 denotes aromatic radical~ other than A1 or arali-
phatic radical~ having 5 to 16, preferably 6 to
12, carbon atom~ or aliphatic radical~ having 2
to 10 carbon atom~, preferably 4 to 8 carbon
atom~,
A3 denote~ aromatic radicals having 5 to 12, prefer-
ably 6 to 10, carbon atoms,
D1 denotes alkylene or polymethylene group~ having
2 to 4 carbon atoms or cycloalkane or
dimethylenecycloalkane group~ having 6 to 10
carbon atoms,
D2 denote~ non-Dl alkylene or polymethylene group~
having 3 to 4 carbon atom~ or cycloalkane or
dimethylenecycloalkane groups having 6 to 10

2~ 7223~
- 15 -
carbon ~tom~ or straight-chain or branched
alkanediyl group~ having 4 to 16, preferably 4 to
8, carbon atom~, or radical~ of the formula
-(C2H4-O)m-C2H4-, where m i~ an integer from 1 to
40, m = 1 or 2 being preferred for proportion~ up
to 20 mol% and group~ having m = 10 to ~0 being
preferably pre~ent only in proportions of below
5 mol%,
the proportion~ of the ba~ic unit~ I and III and
of the modifying units II, IV and V being
~elected within the framework of the above-speci-
fied range~ 80 that the polyester ha~ the de~ired
melting point.
The network structure of the present invention whose
fiber material~ consi~t of ~uch polye~ters, in particul~r
polyethylene terephthalate, are not readily flammable.
The low flammability may be additionally enhanced by
u~ing flame retardant polyester~. Such flame retardant
polye~ter~ are known. They include addition~ of halogen
compound~, in particular bromine compound~, or, particu-
larly advantageously, they include phosphorus compound~
cocondensed in the polyester chain units of the formula
O O (VI)
Il 11
--O-P-R-C--
Rl
where R is alkylene or polymethylene having 2 to 6 carbon
atom~ or phenyl and R1 i8 alkyl having 1 to 6 carbon
atoms, aryl or aralkyl.
Preferably, in the formula VI, R is ethylene and R1 i~
methyl, ethyl, phenyl or o-, m- or p-methylphenyl, in
particular methyl.
The units of the formula VI are advantageously present in
the polyester chain at up to 15 mol%, preferably in a
proportion of 1 to 10 mol%.

217223~
- 16 -
The present invention also provides the consolidated
above-described network structures, i.e. those in which
the lower melting filament~ B of the multifilament hybrid
yarn form at least partially a matrix which interconnects
the higher melting textured filaments of the multifila-
ment hybrid yarn.
It i9 of particular advantage for the polyesters used not
to contain more than 60 meg/kg, preferably less than
30 meq/kg, of capped carboxyl end groups and less than
5 meq/kg, preferably less than 2 meq/kg, in particular
less than 1.5 meq/kg, of free carboxyl end groups.
Preferably, therefore, the polye~ter has, for example by
reaction with mono-, bis- and/or polycarbodiimides,
capped carboxyl end groups.
In a further embodiment, having regard to prolonged
hydrolysi~ stability, it is advantageous for the
polyester to comprise not more than 200 ppm, preferably
not more than 50 ppm, in particular from 0 to 20 ppm, of
mono- and/or biscarbodiimides and from 0.02 to 0.6% by
weight, preferably from 0.05 to 0.5% by weight, of free
polycarbodiimide having an average molecular weight of
2000 to 15,000, preferably of 5000 to 10,000.
The polyesters of the yarns present in the network
structure of the present invention may in addition to the
polymer materials include up to 10% by weight of nonpoly-
meric substances, such as modifying additives, fillers,
delusterants, color pigments, dyes, stabilizers, such as
UV absorber~, antioxidants, hydrolysis, light and
temperature stabilizers and/or processing aids.
The present invention further provides a process for
producing a network structure to be thermally
consolidated by weaving or knitting a flat or relief-
patterned weave or knit, which comprises feeding the
weaving or knitting machine with a yarn which is at least
30%, preferably at least 75%, a multifilament hybrid yarn
consisting of at least 2 varieties A and B of filaments
with or without cofilaments C, wherein

217~236
- 17 -
said filaments A
are textured and have a melting point above 180C,
preferably above 220C, in particular above 250C,
said filaments B
have a melting point below 240C, preferably below
220C, in particular below 200C,
the melting point of said filaments B being at least
20C, preferably at lea~t 40C, in particular at least
80C, below the melting point of said filaments A, and
the weight ratio of said filaments A:B being within the
range from 20:80 to 80:20, preferably from 40:60 to
60:40, and the multifilament hybrid yarn additionally
containing up to 40% by weight of cofilaments C.
subseguently the network structure obtained can be
subjected to a consolidating heat treatment, which is
likewise an optionally integrAl part of the process of
the present invention, at a temperature at which the
lower melting filaments B of said multifilament hybrid
yarn soften. The consolidated network structure thus
produced is likewise part of the subject-matter of the
present invention.
The temperature of the final heat treatment and the
treatment duration depend on the desired degree of
consolidation and the melting point of the filaments B of
the multifilament hybrid yarn.
In general, the heat treatment is carried out at 130 to
220C, preferably at 150 to 200C.
In practice, it will be found very advantageous when the
raw state material of the network ~tructure produced is
pre-set on a tenter at a relatively low temperature, for
example with hot air or by steaming with high pressure
steam.
This eliminates the curling tendency of the raw state
material; it becomes more compliant for the further
processing steps. A particular advantage associated with
pre-setting is that, after cutting, no strengthening of

217223~
- 18 -
the cut edges is required and little, if any, edge-
cutting waste is produced.
Preferably the filaments B in the multifilament hybrid
yarn used are flat.
Furthermore, the process is controlled in accordance with
the requirements of practical performance in such a way
that the network structure has a basis weight from 50 to
250 g/m2, preferAbly 75 to 200 g/m2, in particular 85 to
150 g/m .
The process is controlled in such a way according to the
desired density and patterning that the network structure
will have 1 to 250, preferably 10 to 200, opening~ per
cm2 .
The network structure of the present invention in the
lS preferred embodiment is a single-product material and
therefore exhibits the above-described advantages in
disposAl or recycling. In addition, the present invention
affords further advantages.
It is particularly advantageous that the network
structure, even if it has been woven, exhibits very good
three-dimensional deformability which results from the
use of the herein described multifilament hybrid yarn.
The open network structure of the present invention can
be used with particular advantage for producing light and
vision protectors and for producing air-permeable insect
resistors.
The examples which follow illustrate the production of
the multifilament hybrid yarn of the present invention
And its use in the production of network structures
according to the present invention.

2172236
-- 19 --
Ex~mple 1
Production of the base yarn used:
A 300 dtex hybrid yarn is produced by folding a 167 dtex
32 filament spun-dyed, textured, unmodified polyethylene
terephthalate ~raw material melting point 265C) yarn
(~TREVIRA type 536) with a 140 dtex 24 filament yarn
composed of polyethylene terephthalate modified with
isophthalic acid ~raw material melting point 180C) and
partially oriented by high ~peed spinning, and inter-
mingling in an interlacing jet operated using An airpressure of 2 bar, leaving the lower melting component
essentially flat.
Ex~m~le 2
A single circular knitting machine 8 296, E 12, 26"
cylinder diameter, is used to produce a knit.
Construction: 1:1 tuck piqué with 100% of the multi-
filament hybrid yarn obtained a9 per the description in
Example 1.
Raw material setting: 92 g/m2.
Subsequently the material is washed (open-width wash
40C) and at 190 to 200C tenter dried, stabilized and
finished.
The finished material has a basis weight of 94 g/m2.
Owing to the u~e of the multifilament hybrid yarn, the
otherwise customary edge gluing is not necessary, since
the material, after the thermal treatment, is free of any
tendency to curl at the edges.

Representative Drawing