U.S. patent application number 10/376285 was filed with the patent office on 2003-07-31 for abrasion-resistant spun articles.
Invention is credited to Bouquerel, Franck, Marchand, Jean-Pierre, Varlet, Joel.
Application Number | 20030143396 10/376285 |
Document ID | / |
Family ID | 9547972 |
Filed Date | 2003-07-31 |
United States Patent
Application |
20030143396 |
Kind Code |
A1 |
Bouquerel, Franck ; et
al. |
July 31, 2003 |
Abrasion-resistant spun articles
Abstract
The invention relates to spun articles, threads (yarns), fibers
or filaments which have improved abrasion resistance properties and
which can be used to produce felts for paper machines. The
invention more specifically relates to synthetic resin-based
threads (yarns), fibers or filaments having nanometric-sized
loads.
Inventors: |
Bouquerel, Franck; (Lyon,
FR) ; Varlet, Joel; (Lyon, FR) ; Marchand,
Jean-Pierre; (Lyon, FR) |
Correspondence
Address: |
Norman H. Stepno
BURNS, DOANE, SWECKER & MATHIS, L.L.P.
P.O. Box 1404
Alexandria
VA
22313-1404
US
|
Family ID: |
9547972 |
Appl. No.: |
10/376285 |
Filed: |
March 3, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10376285 |
Mar 3, 2003 |
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09786401 |
Jun 4, 2001 |
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6544644 |
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09786401 |
Jun 4, 2001 |
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PCT/FR00/01933 |
Jul 5, 2000 |
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Current U.S.
Class: |
428/373 ;
428/375 |
Current CPC
Class: |
Y10T 428/2933 20150115;
Y10T 428/2969 20150115; Y10T 428/2927 20150115; D01F 1/10 20130101;
D21F 7/083 20130101; Y10T 428/2913 20150115; Y10T 428/2929
20150115; D01F 6/60 20130101; D21F 1/0027 20130101; D02G 3/442
20130101 |
Class at
Publication: |
428/373 ;
428/375 |
International
Class: |
D02G 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 6, 1999 |
FR |
99/08975 |
Claims
1. Yarns, fibers and filaments based on synthetic resin,
characterized in that they comprise between 0.05% and 20% by weight
of nanometric-sized particles dispersed in the resin and in that
they have an abrasion resistance which is improved by at least 5%
compared with yarns, fibers and filaments made from an identical
resin, of the same viscosity but not containing nanometric-sized
particles, the abrasion resistance being defined by the number of
to and fro motions of a three-roll roller assembly, over a set of
15 fixed yarns, that is required to break 13 of the yarns.
2. The yarns, fibers and filaments as claimed in claim 1,
characterized in that the abrasion resistance is improved by at
least 10%.
3. The yarns, fibers and filaments as claimed in claim 1,
characterized in that the weight concentration of particles is less
than or equal to 5%.
4. The yarns, fibers and filaments as claimed in one of the
preceding claims, characterized in that the synthetic resin is
chosen from polyamides, blends containing polyamides, and
copolymers based on polyamides.
5. The yarns, fibers and filaments as claimed in claim 4,
characterized in that the synthetic resin is based on Nylon-6,
Nylon-6,6 or blends or: copolymers thereof.
6. The yarns, fibers and filaments as claimed in one of the
preceding claims, characterized in that the particles are of
substantially spherical shape and have a mean diameter of less than
or equal to 100 nanometers.
7. The yarns, fibers and filaments as claimed in claim 6,
characterized in that the mean diameter of the particles is less
than or equal to 50 nanometers.
8. The yarns, fibers and filaments as claimed in either of claims 6
and 7, characterized in that the particles are inorganic particles
based on oxides or sulfides of titanium, silicon, zirconium,
cadmium or zinc or are based on mixtures of these compounds.
9. The yarns, fibers and filaments as claimed in one of claims 6 to
8, characterized in that the particles are based on silica.
10. The yarns, fibers and filaments as claimed in claim 9,
characterized in that the silica-based particles are introduced in
the form of a sol into the curing medium of the resin.
11. The yarns, fibers and filaments as claimed in one of claims 1
to 5, characterized in that the particles are in platelet form, the
mean thickness of the platelets being less than 10 nanometers.
12. The yarns, fibers and filaments as claimed in claim 11,
characterized in that the platelets are exfoliable silicates.
13. The yarns, fibers and filaments as claimed in claim 11,
characterized in that the platelets are exfoliable silicates
treated with a swelling agent.
14. The yarns, fibers and filaments as claimed in one of claims 11
to 13, characterized in that the platelets are obtained from
materials chosen from montmorillonites, smectites, illites,
sepiolites, palygorkites, muscovites, allervardites, amesites,
hectorites, talcs, fluorohectorites, saponites, beidellites,
nontronites, stevensites, bentonites, micas, fluoromicas,
vermiculites, fluorovermiculites and halloysites.
15. The yarns, fibers and filaments as claimed in one of claims 11
to 14, characterized in that the platelets are of synthetic or
natural origin.
16. The yarns, fibers and filaments as claimed in one of claims 11
to 15, characterized in that the particles are incorporated into
the resin by introduction into the curing medium of the resin.
17. The yarns, fibers and filaments as claimed in one of claims 11
to 15, characterized in that the particles are incorporated into
the resin by introduction into the melt.
18. A felt for a paper machine, made from yarns, fibers and
filaments as claimed in one of claims 1 to 17.
19. Rugs and carpets made from yarns, fibers or filaments as
claimed in one of claims 1 to 17.
Description
[0001] The present invention relates to spun articles, yarns,
fibers or filaments which have improved abrasion resistance and
which can be used in particular to produce felts for paper
machines. The invention relates more particularly to yarns, fibers
or filaments based on synthetic resin and containing
nanometric-sized fillers.
[0002] The properties which spun articles need to have are
different depending on their use. Among these, mention may be made,
for example, of mechanical strength, transparency, gloss,
whiteness, dyeing ability, shrinkage, capacity for water retention,
fire resistance, stability and heat resistance. One property which
may be demanded, in particular for applications in industrial
fields or the fields of so-called technical yarn, is abrasion
resistance.
[0003] This is the case, for example, for the manufacture of
nonwoven felts from fibers. Increasing the abrasion resistance
generally makes it possible to increase the lifetime of the
articles manufactured from yarns, fibers or filaments. In the case
of felts for paper machines, which are made from synthetic fibers,
this property has become critical following the replacement of
chemical bleaching agents with solid particles, for example calcium
carbonate.
[0004] This is also the case, for example, for the manufacture of
rugs and carpets from fibers. In this case, the mechanical rubbing
or abrasion stresses on the rug or carpet are such that the
abrasion resistance property directly characterizes the lifetime of
the rug or carpet.
[0005] One known solution for improving the abrasion resistance of
spun articles is to increase the degree of curing of the synthetic
material from which they are made. This is the way in which fibers
made from thermoplastic resins of increasingly high viscosity are
developed. Patent US-A-5 234 644 discloses, for example, a process
for increasing the viscosity of polymers. However, this solution
has limits. Specifically, the spinning of fibers of very high
viscosity requires the use of very high spinning pressures and/or
very high spinning temperatures, which may result in degradation of
the polymer.
[0006] Another solution for improving the abrasion resistance of
articles made from fibers consists in using articles with
three-dimensional crimping.
[0007] The aim of the present invention is to propose another
solution for obtaining spun articles with high abrasion
resistance.
[0008] To this end, the invention proposes yarns, fibers and
filaments based on synthetic resin, characterized in that they
comprise between 0.05% and 20% by weight of nanometric-sized
particles dispersed in the resin and in that they have an abrasion
resistance which is improved by at least 5%,compared with yarns,
fibers and filaments made from an identical resin, of the same
viscosity but not containing nanometric-sized particles. The
abrasion resistance is defined by the number of to and fro motions
of a three-roll roller assembly, over a set of 15 fixed yarns, that
is required to break 13 of the yarns.
[0009] This solution furthermore has the advantage of being able to
be combined with an improvement in the abrasion resistance by
increasing the viscosity of the resin.
[0010] The expression "nanometric-sized particle" means any object
for which at least one characteristic size parameter (diameter,
length, thickness) is less than or equal to 100 nanometers,
preferably less than or equal to 50 nm. The particles may be, for
example, substantially spherical, with a nanometric-sized diameter.
The particles may be in the shape of platelets or needles, i.e.
shapes for which it is possible to define at least one large size
parameter and at least one small size parameter. In this case, the
small size parameter is advantageously less than 50 nm and
preferably 10 nm. For example, the particles may be platelets less
than 10 nm thick with a form factor, .i.e. a ratio of large size to
small size, of greater than 10.
[0011] The weight proportion of the particles relative to the total
weight of the material is between 0.05% and 20%. It is
advantageously less than or equal to 5%.
[0012] The synthetic resin constituting the matrix in which the
particles are dispersed may be chosen from any spinnable polymer.
It consists, for example, of polyamide or polyester, a blend of
polymers comprising polyamide or polyester, or copolymers based on
polyamide or polyester. As examples of polyamides which are
suitable for carrying out the invention, mention may be made in
particular of Nylon-6 and Nylon-6,6, and blends and copolymers
thereof.
[0013] The yarns, fibers and filaments according to the invention
may contain any additive usually used with such polymers, for
example heat stabilizers, UV stabilizers, catalysts, pigments, dyes
and antibacterial agents.
[0014] According to a first embodiment of the invention, the
particles dispersed in the synthetic resin matrix are of
substantially spherical shape with a mean diameter of less than or
equal to 100 nanometers. According to one preferred embodiment, the
mean diameter of these particles is less than or equal to 50
nanometers.
[0015] The particles may be chosen from particles based on
inorganic materials. They may be metallic or mineral, obtained from
a natural source or may be synthesized. Examples of suitable
materials which may be mentioned include silver, copper, gold and
the oxides and sulfides of metals, for example of silicon,
zirconium, titanium, cadmium or zinc. Silica-based particles may be
used in particular.
[0016] The particles may have been subjected to treatments to make
them compatible with the matrix. These treatments are, for example,
surface treatments or a surface deposition of a compound other than
that constituting the core of the particles. Treatments and
depositions may similarly be carried out in order to promote the
dispersion of the particles, either in the polymerization medium of
the matrix or in the molten polymer.
[0017] The surface of the particles may comprise a protective layer
intended to prevent any degradation of the polymer in contact with
these particles. Metal oxides, for example silica, in a continuous
or discontinuous layer, may thus be deposited at the surface of the
particles.
[0018] Any method for obtaining a dispersion of particles in a
resin may be used to carry out the invention. A first process
consists in melt-blending the particles in resin and in optionally
subjecting the mixture to high shear, for example in a twin-screw
extrusion device, in order to achieve good dispersion. Another
process consists in mixing the particles with the monomers in the
curing medium, and then in curing the resin. Another process
consists in melt-blending a concentrated mixture of a resin and
particles, prepared, for example, according to one of the processes
described above.
[0019] There is no limitation on the form in which the particles
are introduced and mixed with the monomers or the melt. The
particles may be introduced in the form of powder or in the form of
an optionally stablilized aqueous solution. For example, a silica
sol may be introduced into the curing medium of the resin.
[0020] According to a second embodiment of the resin, the particles
dispersed in the synthetic resin matrix are in the form of
platelets less than 10 nanometers thick. Preferably, the thickness
is less than 5 nanometers. The particles are preferably dispersed
in the matrix in individual form. However, aggregates may exist and
are preferably less than 100 nm thick and even more preferably less
than 50 nm thick.
[0021] The platelets are advantageously obtained from exfoliable
silicate leaflets. The exfoliation may be promoted by a prior
treatment with a swelling agent, for example by exchange of the
cations initially contained in the silicates with organic cations
such as oniums. The organic cations may be chosen from phosphoniums
and-ammoniums, for example primary to quaternary ammoniums. Mention
may be made, for example, of protonated amino acids such as
12-aminododecanoic acid, protonated primary to tertiary ammoniums,
and quaternary ammoniums. The chains attached to the nitrogen or
phosphorus atom of the onium may be aliphatic, aromatic,
aryaliphatic, linear or branched and may contain oxygenated units,
for example hydroxyl or ethoxy units. As examples of organic
ammonium treatments, mention may be made of dodecylammonium,
octadecylammonium, bis(2-hydroxyethyl)octadecylmethyl-ammonium,
dimethyldioctadecylammonium, octadecylbenzyl-dimethylammonium and
tetramethylammonium. As examples of organic phosphonium treatments,
mention may be made of alkylphosphoniums such as
tetrabutylphosphonium, trioctyloctadecylphosphonium and
octadecyltriphenyl-phosphonium. These lists do not have any
limiting nature.
[0022] The silicate leaflets which are suitable for carrying-out
the invention may be chosen from montmorillonites, smectites,
illites, sepiolites, palygorkites, muscovites, allervardites,
amesites, hectorites, talcs, fluorohectorites, saponites,
beidellites, nontronites, stevensites, bentonites, micas,
fluoromicas, vermiculites, fluorovermiculites and halloysites.
These compounds may be of natural, synthetic or modified natural
origin.
[0023] According to one preferred embodiment of the invention, the
yarns, fibers and filaments are composed of polyamide resin and of
platelet particles dispersed in the resin, obtained by exfoliation
of a phyllosilicate, for example a montmorillonite which has
undergone a prior swelling treatment by ion exchange. Examples of
swelling treatments which may be used are disclosed, for example,
in patent EP-A-0 398 551. All the known treatments for promoting
the exfoliation of phyllosilicates in a polymer matrix may be used.
It is possible, for example, to use a clay treated with an organic
compound sold by the company Laporte under the brand name
Cloisite.RTM..
[0024] Any method for obtaining a dispersion of particles in a
resin may be used to carry out the invention. A first process
consists in mixing the compound to be dispersed, optionally
treated, for example, with a swelling agent, in the melt and in
optionally subjecting the mixture to high shear, for example in a
twin-screw extrusion device, in order to achieve good dispersion.
Another process consists in mixing the compound to be dispersed,
optionally treated, for example, with a swelling agent, with the
monomers in the curing medium, and then in curing the resin.
Another process consists in melt-blending a concentrated mixture of
a resin and dispersed particles, prepared, for example, according
to one of the processes described above.
[0025] There is no limitation on the form in which the particles
are introduced and mixed with the monomers or the melt. The
particles may be introduced in the form of a powder of exfoliable
compound or in the form of a dispersion in water or in an organic
dispersant of an exfoliable compound.
[0026] The spun articles, yarns, fibers or filaments are made
according to the usual spinning techniques from a material
comprising the synthetic resin and the particles. The spinning may
be carried out immediately after curing the resin, this resin being
in molten form. It may be carried out using a granular composite
comprising the particles and the synthetic resin. The particles may
be incorporated into the molten polymer before the spinning
operation in the form of a concentrated mixture in a polymer. Any
method for incorporating particles into a polymer to be spun may be
used.
[0027] The spun articles according to the invention may be
subjected to any treatment which may be carried out in steps
subsequent to the spinning step. They may in particular be drawn,
textured, crimped, heated, twisted, dyed, sized, chopped, etc.
These additional operations may be carried out continuously and may
be incorporated after the spinning device or may be carried out in
batchwise mode. The list of operations subsequent to the spinning
operation has no limiting nature.
[0028] The spun articles according to the invention may be used in
woven, knitted or nonwoven form. The fibers according to the
invention are suitable in particular for the manufacture of felts
for paper machines. They may also be used for the manufacture of
yarns for carpets.
[0029] Other details or advantages of the invention will emerge
more clearly in the light of the example below, which is given
purely as a guide.
[0030] The properties and characteristics of the yarns according to
the invention are determined according to the following
methods:
[0031] Mechanical characterization (elongation at break, tensile
strength): carried out on an Erichsen tensile machine placed in an
air-conditioned location at 50% RH and 23.degree. C. after
conditioning the yarns for 72 hours under these conditions. The
initial length of the yarns is 50 mm and the traveling speed is 50
mm/min.
[0032] Abrasion resistance: a simultaneous friction is applied to
15 immobile yarns whose tension is kept constant at 15 yarns by 3
brass rolls forming a roller assembly. The point of application of
the rolling zone is moved along the yarns over an amplitude of 90
mm at a frequency of 220 cycles per minute. The abrasion resistance
is defined by the number of cycles (to and fro) required to break
13 of the 15 yarns. The measurements given are the averages of the
values obtained on three tests with similar yarns.
EXAMPLES 1 and 2
[0033] A sol of silica nanospheres of the brand name Klebosol.RTM.
with a mean diameter equal to 50 nm, sold by the company Hoechst,
is introduced into caprolactam. The sol is introduced as an aqueous
phase at a weight concentration of 30%.
[0034] The curing of the caprolactam is carried out according to a
usual process. After curing, a polymer is obtained with an absolute
molar mass of 34 980 g/mol, determined by GC, and a viscosity index
of 140 ml/g. The polymer is washed and then dried for 16 hours at
110.degree. C. under a primary vacuum.
[0035] The polymer is then spun at low speed in the form of a round
monofilament through a die about 1 mm in diameter. The yarn
obtained has a diameter of about 250 .mu.m. The yarn is then drawn
by pinching between two rollers. The draw ratio is equal to the
ratio of the rotation speeds of the rollers. Different draw ratios
are applied.
[0036] The characteristics of the yarns obtained are as
follows:
1 Elongation Tensile 5% Secant Abrasion at break strength modulus
resistance Draw ratio (%) (MPa) (MPa) (cycles) Example 1 4.37 28.8
752 2.44 1 875 Example 2 5.04 21.9 868 3.04 1 375
EXAMPLES 3 and 4
[0037] 5% by weight of a clay treated with an organic compound sold
by the company Laporte under the name Cloisite 25A, a sodium
montmorillonite which has undergone an ion exchange with
dimethyl-2-ethylhexyl-(hydrogena- ted tallow)ammonium methyl
sulfate, of 95 to 100 milliequivalents per 100 g of
montmorillonite, is introduced into Nylon-6. Nylon-6 is a
commercial compound with a viscosity index of 140 ml/g, sold under
the name Technyl.RTM.. The incorporation is carried out in a
Leistritz twin-screw extruder with a diameter of 34 mm.
[0038] The compound obtained is spun and drawn under the same
conditions as those described in Examples 1 and 2.
[0039] The characteristics of the yarns obtained are as
follows:
2 Elongation Tensile 5% Secant Abrasion at break strength modulus
resistance Draw ratio (%) (MPa) (MPa) (cycles) Example 3 4.28 27.4
491 4.68 5 200 Example 4 5.02 19.3 777 6.51 3 800
EXAMPLES 5 and 6
[0040] 3% by weight of a clay treated with an organic compound sold
by the company Laporte under the name Cloisite 25A, a sodium
montmorillonite which has undergone an ion exchange with
dimethyl-2-ethylhexyl-(hydrogena- ted tallow)ammonium methyl
sulfate, of 95 to 100 milliequivalents per 100 g of
montmorillonite, is introduced into Nylon-6. Nylon-6 is a
commercial compound with a viscosity index of 140 ml/g, sold under
the name Technyl.RTM.. The incorporation is carried out in a
Leistritz twin-screw extruder with a diameter of 34 mm.
[0041] The compound obtained is spun and drawn under the same
conditions as those described in Examples 1 and 2.
[0042] The characteristics of the yarns obtained are as
follows:
3 Elongation Tensile 5% Secant Abrasion at break strength modulus
resistance Draw ratio (%) (MPa) (MPa) (cycles) Example 5 4.10 30.0
519 3.52 6 300 Example 6 4.65 19.6 625 4.21 5 500
EXAMPLES 7 and 8
[0043] 1% by weight of a clay treated with an organic compound sold
by the company Laporte under the name Cloisite 25A, a sodium
montmorillonite which has undergone an ion exchange with
dimethyl-2-ethylhexyl-(hydrogena- ted tallow)ammonium methyl
sulfate, of 95 to 100 milliequivalents per 100 g of
montmorillonite, is introduced into Nylon-6. Nylon-6 is a
commercial compound with a viscosity index of 140 ml/g, sold under
the name Technyl.RTM.. The incorporation is carried out in a
Leistritz twin-screw extruder with a diameter of 34 mm.
[0044] The compound obtained is spun and drawn under the same
conditions as those described in Examples 1 and 2.
[0045] The characteristics of the yarns obtained are as
follows:
4 Elongation Tensile 5% Secant Abrasion at break strength modulus
resistance Draw ratio (%) (MPa) (MPa) (cycles) Example 7 4.15 31.0
563 3.84 6 400 Example 8 4.78 24.3 685 4.57 4 400
EXAMPLES 9 and 10
[0046] 5% by weight of a clay treated with an organic compound sold
by the company Laporte, a sodium montmorillonite which has
undergone an ion exchange with dimethyldioctadecylammonium
chloride, of 120 milliequivalents per lo g of montmorillonite, is
introduced into Nylon-6. Nylon-6 is a commercial compound with a
viscosity index of 140 ml/g, sold under the name Technyl.RTM.. The
incorporation is carried out in a Leistritz twin-screw extruder
with a diameter of 34 mm.
[0047] The compound obtained is spun and drawn under the same
conditions as those described in Examples 1 and 2.
[0048] The characteristics of the yarns obtained are as
follows:
5 Elongation Tensile 5% Secant Abrasion at break strength modulus
resistance Draw ratio (%) (MPa) (MPa) (cycles) Example 9 4.62 23.8
528 2.66 2 300 Example 10 5.33 17.0 650 4.28 1 575
EXAMPLES 11 and 12
[0049] 5% by weight of a clay treated with an organic compound sold
by the company Laporte, a sodium montmorillonite which has
undergone an ion exchange with methyl-N,N-bis(hydroxyethyl)(ester
of hydrogenated 2-hydroxyethyl tallow)ammonium methyl sulfate, of
95 to 120 milliequivalents per 100 g of montmorillonite, is
introduced into Nylon-6,6. Nylon-6,6 is a commercial compound with
a viscosity index of 140 ml/g, sold by the company Nyltech. The
incorporation is carried out in a Leistritz twin-screw extruder
with a diameter of 34 mm.
[0050] The compound obtained is spun and drawn under the same
conditions as those described, in Examples 1 and 2.
[0051] The characteristics of the yarns obtained are as
follows:
6 Elongation Tensile 5% Secant Abrasion at break strength modulus
resistance Draw ratio (%) (MPa) (MPa) (cycles) Example 11 3.94 25.0
372 3.7 5 200 Example 12 4.72 17.1 501 4.7 4 200
Comparative Examples 1 and 2
[0052] A Nylon-6 with a viscosity of 140 ml/g is spun and drawn
under the same conditions as those described in Examples 3 to
10.
[0053] The characteristics of the yarns obtained are as
follows:
7 Elongation Tensile 5% Secant Abrasion at break strength modulus
resistance Draw ratio (%) (MPa) (MPa) (cycles) Comparative 4.34
33.7 660 3.72 1 700 Example 11 Comparative 5.16 20.0 975 5.74 1 000
Example 21
Comparative Examples 3 and 4
[0054] A Nylon-6,6 with a viscosity index of 140 ml/g is spun and
drawn under the same conditions as those described in Examples 11
and 12.
[0055] The characteristics of the yarns obtained are as
follows:
8 Elongation Tensile 5% Secant Abrasion at break strength modulus
resistance Draw ratio (%) (MPa) (MPa) (cycles) Comparative 4.09
37.5 480 3.3 5 050 Example 3 Comparative 4.85 22.2 672 4.2 3 000
Example 4
* * * * *