U.S. patent number 3,928,696 [Application Number 05/286,913] was granted by the patent office on 1975-12-23 for stitched webs of fleeces of synthetic fibers and method of making same.
This patent grant is currently assigned to Bayer Aktiengesellschaft. Invention is credited to Gotz Gotmar Dornheim, Bernard Kuhlmann, Manfred Salamon, Martin Wandel.
United States Patent |
3,928,696 |
Wandel , et al. |
December 23, 1975 |
Stitched webs of fleeces of synthetic fibers and method of making
same
Abstract
Erosion preventing structural elements in the form of stitched
fleeces comprising a fleece from polyamide staple fibers of certain
dtex and length, a mesh fabric of synthetic endless yarns and a
waterproof binder.
Inventors: |
Wandel; Martin (Dormagen,
DT), Salamon; Manfred (Dormagen, DT),
Dornheim; Gotz Gotmar (Leichlingen, DT), Kuhlmann;
Bernard (Rheydt, DT) |
Assignee: |
Bayer Aktiengesellschaft
(Leverkusen-Bayerwerk, DT)
|
Family
ID: |
6623701 |
Appl.
No.: |
05/286,913 |
Filed: |
September 7, 1972 |
Foreign Application Priority Data
Current U.S.
Class: |
428/102; 442/35;
28/112; 428/152; 405/19; 156/93 |
Current CPC
Class: |
D04H
1/593 (20130101); E02B 3/126 (20130101); D04H
13/00 (20130101); D04H 1/44 (20130101); D04H
1/645 (20130101); D04H 1/52 (20130101); D04H
1/4334 (20130101); Y10T 428/24033 (20150115); Y10T
442/159 (20150401); Y02A 10/30 (20180101); Y10T
428/24446 (20150115) |
Current International
Class: |
E02B
3/12 (20060101); D04H 13/00 (20060101); B32B
007/08 (); B32B 027/02 (); B32B 003/28 (); E02B
003/12 () |
Field of
Search: |
;161/50,89,128 ;28/77
;61/38 ;428/102,255,152 ;156/93 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Dier; Philip
Attorney, Agent or Firm: Plumley & Tyner
Claims
What we claim is:
1. An erosion preventing structural element in the form of a
stitched web of fleece of coarse, crimped fibres, consisting of a
web of fleece produced from
a. crimped polyamide fibres of dtex 5 to 250 and staple length 20
to 150 mm stitched with 60 to 180 stitches per cm.sup.2,
b. a mesh fabric of synthetic endless yarns stitched into the
fleece, the fabric having at least 2 warp yarns and 2 weft yarns
per cm.sup.2 and being arranged in the lower third of the web of
fleece, and
c. a waterproof binder based on polyacrylic acid ester of at least
15% by weight, this web of fleece having a thickness of 4 to 10 mm
and a weight per m.sup.2 of between 500 and 2000 g.
2. The erosion preventing structural element of claim 1, said
crimped polyamide fibres having 80 to 110 stitches per
cm.sup.2.
3. A process for the production of erosion preventing structural
elements in the form of webs of stitched fleeces of synthetic
fibres, which comprises laying crimped polyamide staple fibres of
dtex 5 to 250 to form a fleece, stitching together the formed
fleece and a mesh fabric, impregnating the resultant combination
with a waterproof binder based on polyacrylate and subjecting the
impregnated fleece to a heat treatment at temperatures of between
100.degree. and 150.degree.C.
4. The process according to claim 3, in which said binder is
applied as an aqueous dispersion.
5. The process according to claim 4, in which aqueous dispersion of
binder contains a filler having a high specific gravity.
6. The process according to claim 3, in which said laying is
achieved by an aerodynamic process.
7. The process according to claim 3, in which said laying is
achieved on a carding machine.
8. The erosion preventing structural element according to claim 1
which contains 2 to 20% by weight of a wetting agent.
9. The erosion preventing structural element according to claim 1,
wherein said mesh fabric consists of 4 warp yarns and 4 weft yarns
of dtex 900 to 1200 per cm.sup.2 and has a weight per m.sup.2
between 100 and 150 g.
10. The process according to claim 3, wherein said stitched fleece
and mesh fabric combination is impregnated with an aqueous solution
of a wetting agent.
Description
This invention relates to erosion preventing structural elements
which consist of stitched webs of fleeces made of coarse, crimped
polyamide fibres.
It is known to use synthetic fibre fabrics for reinforcing dams and
the walls of water reservoirs and containers. For larger objects,
however, the use of textile fabrics as erosion preventing and
reinforcing elements is out of the question because of economical
or functional considerations.
The use of webs of non-woven fleeces of synthetic fibres as erosion
preventing elements for reinforcing dykes, banks, strands, dams and
embankments of river courses and canals is also known. The three
dimensional form of such a web of fleece provides the desired
filtering effect and in addition the elastic properties of the web
enable it to fit closely to the ground on which it is laid, thereby
preventing erosion and slipping of the ground.
These fleeces are resistant to rotting and decay. Fleece binders
are applied to fix the points of intersection and contact between
the fibres and the fleeces may also be bonded by means of
thermoplastic adhesive fibres.
These bulky fleece webs are laid down wherever it is required to
prevent erosion by water and/or wind. They are fixed in position
e.g. by weighing them down with stones or covering them with sand,
gravel or asphalt, concrete and/or soil or by nailing them down
with stakes, etc.. These webs of fleece may also be used for fixing
turf and for arresting the movement of dunes and for reinforcing
dams or dykes.
It has been found, however, that normal fleece constructions do not
always have sufficient strength and dimensional stability to
perform their reinforcing function.
It is an object of this invention to provide structural elements
that do not have these deficiencies. This object is accomplished by
an erosion preventing structural element in the form of a stitched
web of fleece made of coarse synthetic fibres, which comprises
A. crimped polyamide fibres with dtex 5 to 250, preferably dtex 30
to 140, and staple lengths 20 to 150 mm, preferably 50 to 100 mm,
stitched with 60 to 180 stitches per cm.sup.2, preferably 80-120
stitches per cm.sup.2,
B. a mesh fabric of synthetic yarns or tapes comprising at least
two warp yarns and two weft yarns per cm.sup.2 stitched into the
web in the lower third thereof and
C. at least 15% by weight and preferably 20 to 45% by weight
--based on the weight of the fleece-- of a waterproof binder based
on polyacrylic acid esters, this web of fleece having a thickness
of 4 to 10 mm and a weight per square metre of between 500 and 2000
g, preferably between 500 and 1700 g.
The erosion preventing structural element according to the
invention is produced by a process which comprises laying crimped
polyamide staple fibres of dtex 5 to 250 to form a fleece, the
formed fleece and a mesh being stitched together, the stitched
fleece being impregnated with a waterproof binder based on
polyacrylate and subjecting the impregnated fleece to a heat
treatment at temperatures of between 100.degree. and
150.degree.C.
The waterproof binders based on polyacrylates are, for example,
binders produced from self cross-linking acrylic acid esters,
preferably butyl acrylate. They are preferably applied in the form
of aqueous dispersions. Fillers such as barium sulphate, kaolin or
chalk may be added to the aqueous dispersions to increase the
weight of the element so that the web will sink more quickly when
laid under water. Sinking of the web may also advantageously be
speeded up by the addition of wetting agents (tensides) in
quantities of 2 to 20% by weight, preferably 4 to 10% by weight,
based on the finished web of fleece. The wetting agents used may be
alkyl-(aryl) sulphonic acids or sulphonates or also non-ionogenic
compounds.
The mesh fabric is advantageously produced from multifilamentary
polyester yarns of dtex 900 to 1200 woven to produce a fabric
having 4 warp yarns and 4 weft yarns per cm.sup.2 ; the weight per
square metre of the mesh fabric should be between 80 and 160 g. The
fabric is arranged in the lower third of the web of fleece so that
loops of fibres projecting from the undersurface of the fleece will
provide a firm hold on the ground which is to be protected. The
layers of fleece on both sides of the mesh fabric are protected
against mechanical damage, for example from gravel or broken
stone.
It is only by observing the special conditions indicated above
(titre of the fibres of the fleece, formation of the fleece,
specified mesh fabric, density of stitching, binder content and
other fillers, and thickness and weight per square metre of the web
of fleece), which vary according to the conditions under which the
fleece is to be used, for example the size of the particles of the
ground which is to be protected, that optimum properties are
obtained in these fleeces as regards their strength and functional
suitability so that they satisfy all requirements for use in the
construction of dykes and canals.
The webs of fleece may be produced by known methods in any fleece
forming installations, preferably by the aerodynamic principle. The
binder is introduced into the web of stitched fleece in the form of
an aqueous dispersion, for example by slop padding or spraying, and
is then condensed, usually at elevated temperatures. In this
operation, the web of fleece may be drawn through a pair of heated
rollers (Calender rollers). The process for producing erosion
preventing structural elements in the form of webs and stitched
fleeces is characterised in that crimped polyamide staple fibres of
dtex 5 to 250 are laid to form a fleece by an aerodynamic process
and/or using a carding machine, and the fleece is then stitched to
a mesh fabric and the stitched fleece is impregnated with a
waterproof polyacrylate binder and the impregnated fleece is
subjected to a heat treatment at temperatures of between
100.degree. to 150.degree.C. In order to produce self-sinking mats,
the mats produced by the process indicated above are treated with a
wetting agent (tenside), preferably 2 to 20% by weight. If desired,
sinking may be facilitated by applying a filler of high specific
gravity (e.g. barium sulphate, kaolin or chalk) together with a
binder.
The following Examples illustrate more particularly the
invention.
EXAMPLE 1
Polyamide-6 staple fibres (70% by weight of fibres of dtex 70 and
staple length 90 mm and 30% by weight of a mixture of fibres of
dtex 5 to 30) were mixed in a fibre mixing machine and continuously
formed into a web of fleece weighing about 500 g/m.sup.2 on a
carding machine. The resulting web of fleece and a polyester mesh
fabric (endless multifilament fibres 1100 dtex, 4 warp yarns and 4
weft yarns per cm.sup.2) are stitched together with 110 stitches
per cm.sup.2 using a 28 gauge needle. A 20% by weight aqueous
dispersion of polybutyl acrylate is applied by padding to the
stitched fleece (passed over heated rollers and squeezed off) and
dried at 120.degree.C and then condensed at temperatures of about
150.degree.C.
EXAMPLE 2
Polyamide-6 staple fibres (130 dtex, staple length 60 mm) are
worked up in an aerodynamic fleece laying apparatus to form a web
of fleece weighing 1000 g per m.sup.2. The fleece is then treated
as described in Example 1 and after condensation of the polybutyl
acrylate it is impregnated with a 70% by weight aqueous solution of
a wetting agent mixture consisting of 70% by weight of alkyl
(C.sub.12 to C.sub.22) sulphonate and 30% by weight of
nonylphenolpolyglycol ether (7 mols of ethylene oxide), 120 g of
this solution being introduced per m.sup.2 of fleece web. After
drying at 100.degree.C, the finished web of fleece contains 6% by
weight of wetting agent and has a final weight of about 1500
g/m.sup.2 and a thickness of 9 mm.
The figure illustrates an example of an erosion preventing
structural element according to the invention in the form of a web
of fleece (in cross-section) of polyamide-6 fibres.
Fleece 1 is composed of polyamide-6 fibers 2 (diameter 0.10 mm,
staple length 60 mm), some of the loops of fibers being stitched
through the mesh fabric consisting of warp yarns 3 and weft yarns 4
mechanical strengthening of the web was carried out in a stitching
apparatus by applying 90 stitches per cm.sup.2 with 28 gauge
needles. The polyacrylate binder content is 30% by weight.
The mesh fabric has 4 warp threads and 4 weft threads of
multifilament polyester fibres of 1100 dtex and has a weight per
m.sup.2 of 110 g. The finished web of fleece has a thickness of 8
mm and a weight per m.sup.2 of 1600 g.
* * * * *