U.S. patent application number 14/651335 was filed with the patent office on 2015-11-12 for caco3 in polyester for nonwoven and fibers.
The applicant listed for this patent is Omya International AG. Invention is credited to Martin Brunner, Tazio Fomera, Erik Laursen, Francesco Pullega, Samuel Rentsch, Michael Tinkl.
Application Number | 20150322604 14/651335 |
Document ID | / |
Family ID | 47603138 |
Filed Date | 2015-11-12 |
United States Patent
Application |
20150322604 |
Kind Code |
A1 |
Brunner; Martin ; et
al. |
November 12, 2015 |
CaCO3 IN POLYESTER FOR NONWOVEN AND FIBERS
Abstract
The present invention concerns a nonwoven fabric comprising at
least one polymer comprising a polyester and at least one filler
comprising calcium carbonate. The present invention further relates
to a process of producing such a nonwoven fabric as well as to the
use of calcium carbonate as filler in a nonwoven fabric comprising
at least one polymer comprising a polyester.
Inventors: |
Brunner; Martin; (Wallbach,
CH) ; Laursen; Erik; (Haslev, DK) ; Pullega;
Francesco; (Bologna, IT) ; Fomera; Tazio;
(Zofingen, CH) ; Tinkl; Michael; (Gipf-Oberfrick,
CH) ; Rentsch; Samuel; (Aarburg, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Omya International AG |
Oftringen |
|
CH |
|
|
Family ID: |
47603138 |
Appl. No.: |
14/651335 |
Filed: |
December 20, 2013 |
PCT Filed: |
December 20, 2013 |
PCT NO: |
PCT/EP2013/077742 |
371 Date: |
June 11, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61748779 |
Jan 4, 2013 |
|
|
|
Current U.S.
Class: |
442/365 ;
264/210.8 |
Current CPC
Class: |
D04H 1/435 20130101;
D01F 6/62 20130101; Y10T 442/642 20150401; D01F 1/10 20130101; D04H
3/011 20130101 |
International
Class: |
D04H 3/011 20060101
D04H003/011; D04H 1/435 20060101 D04H001/435 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2012 |
EP |
12199746.4 |
Claims
1. A nonwoven fabric comprising at least one polymer comprising a
polyester, and at least one filler comprising calcium
carbonate.
2. The nonwoven fabric of claim 1, wherein the polyester is
selected from the group consisting of a polyglycolic acid, a
polycaprolactone, a polyethylene adipate, a polyhydroxyalkanoate, a
polyhydroxybutyrate, a polyethylene terephthalate, a
polytrimethylene terephthalate, a polybutylene terephthalate, a
polyethylene naphthalate, a polylactic acid, or a mixture thereof,
or copolymers thereof, preferably the polyester is a polyethylene
terephthalate.
3. The nonwoven fabric of claim 1, wherein the polyester has a
number average molecular weight from 5000 to 100000 g/mol,
preferably from 10000 to 50000 g/mol, and more preferably from
15000 to 20000 g/mol.
4. The nonwoven fabric of claim 1, wherein the calcium carbonate is
ground calcium carbonate, precipitated calcium carbonate, modified
calcium carbonate, surface-treated calcium carbonate, or a mixture
thereof, preferably surface-treated calcium carbonate.
5. The nonwoven fabric of claim 1, wherein the calcium carbonate
has an average particle size d.sub.50 from 0.1 to 3 .mu.m,
preferably from 0.4 to 2.5 .mu.m, more preferably from 1.0 to 2.3
.mu.m, and most preferably from 1.2 to 1.8 .mu.m.
6. The nonwoven fabric of claim 1, wherein the calcium carbonate
has an top cut particle size d.sub.98 from 1 to 10 .mu.m,
preferably from 5 to 8 .mu.m, more preferably from 4 to 7 .mu.m,
and most preferably from 6 to 7 .mu.m.
7. The nonwoven fabric of claim 1, wherein the calcium carbonate is
present in the nonwoven fabric in an amount from 0.1 to 50 wt.-%,
preferably from 0.2 to 40 wt.-%, and more preferably from 1 to 35
wt.-%, based on the total weight of the nonwoven fabric.
8. A process for producing a nonwoven fabric comprising the steps
of a) providing a mixture of at least one polymer comprising a
polyester and at least one filler comprising calcium carbonate, b)
forming the mixture into fibers, filaments and/or film-like
filamentary structures, and c) forming a nonwoven fabric from the
fibers, filaments and/or film-like filamentary structures.
9. The process of claim 8, wherein in step b) the mixture is formed
into fibers, preferably by an extrusion process, and more
preferably by a melt blown process, a spunbond process, or a
combination thereof.
10. The process of claim 9, wherein the nonwoven fabric is formed
by collecting the fibers on a surface or carrier.
11. The process of claim 8, wherein steps b) and c) are repeated
two or more times to produce a multilayer nonwoven fabric,
preferably a spundbonded-meltblown-spunbonded (SMS), a
meltblown-spunbonded-meltblown (MSM), a
spundbonded-meltblown-spunbonded-meltblown (SMSM), a
meltblown-spunbonded-meltblown-spunbonded (MSMS), a
spundbonded-meltblown-meltblown-spunbonded (SMMS), or a
meltblown-spunbonded-spunbonded-meltblown (MSSM) nonwoven
fabric.
12-13. (canceled)
14. Construction products, waterproofing, thermal insulation,
soundproofing, roofing, consumer apparel, upholstery and clothing
industries, industrial apparel, medical products, home furnishings,
protective products, packaging materials, cosmetic products,
hygiene products, or filtration materials comprising the nonwoven
fabric according to claim 1.
15. Construction products, consumer apparel, industrial apparel,
medical products, home furnishings, protective products, packaging
materials, cosmetic products, hygiene products, or filtration
materials comprising the nonwoven fabric according to claim 1.
Description
[0001] The invention relates to a nonwoven fabric, a process for
preparing a nonwoven fabric, articles containing said nonwoven
fabric, and the use of said nonwoven fabric as well as to the use
of fibers for the manufacture of nonwoven fabrics and the use of
calcium carbonate as fillers for nonwoven fabrics.
[0002] Nonwoven fabrics are sheets or web structures made by
bonding together fibers or filaments. They can be flat or bulky
and, depending upon the process by which they are produced and the
materials used, can be tailored for a variety of applications. In
contrast to other textiles such as woven fabrics or knitted
fabrics, nonwoven fabrics need not to go through the preparatory
stage of yarn spinning in order to be transformed into a web of a
certain pattern. Depending on the strength of material needed for
the specific use, it is possible to use a certain percentage of
recycled fabrics in the nonwoven fabric. Conversely, some nonwoven
fabrics can be recycled after use, given the proper treatment and
facilities. Therefore, nonwoven fabrics may be the more ecological
fabric for certain applications, especially in fields and
industries where disposable or single use products are important
such as hospitals, schools or nursing homes.
[0003] Today, nonwoven fabrics are mainly produced from
thermoplastic polymers such as polypropylene, polyethylene,
polyamides, or polyesters. The advantage of polyester fibers or
filaments is their high crystallinity, high strength and high
tenacity. Polyethylene terephthalate (PET) is the most widely used
polyester class and is characterized by high modulus, low
shrinkage, heat set stability, light fastness and chemical
resistance account for the great versatility of PET. One major
drawback of PET is its slow crystallization rate, which does not
allow reasonable cycle times for manufacturing processes such as
injection molding. Therefore nucleating agents such as talc are
often added. However, these heterogeneous particles can act as
stress concentrators, and thereby, may affect the mechanical
properties of the polymer. Therefore, nucleated PET is often
reinforced with glass fibers.
[0004] A talc filled PET is disclosed in the article of Sekelik et
al. entitled "Oxygen barrier properties of crystallized and
talc-filled poly(ethylene terephthalate)" published in Journal of
Polymer Science: Part B: Polymer Physics, 1999, 37, 847 to 857.
U.S. Pat. No. 5,886,088 A is concerned with a PET resin composition
comprising an inorganic nucleating agent. A method for producing a
thermoplastic polymer material, which is filled with calcium
carbonate is described in WO 2009/121085 A1. WO 2012/052778 A1
relates to tearable polymer films comprising a polyester and
calcium carbonate or mica fillers. The spinning of PET fibers
containing modified calcium carbonate was studied by Boonsri
Kusktham and is described in the article entitled "Spinning of PET
fibres mixed with calcium carbonate", which was published in the
Asian Journal of Textile, 2011, 1(2), 106 to 113.
[0005] Extruded fibers and nonwoven webs containing titanium
dioxide and at least one mineral filler are disclosed in U.S. Pat.
No. 6,797,377 B1. WO 2008/077156 A2 describes spunlaid fibers
comprising a polymeric resin and one filler as well as nonwoven
fabrics containing said fibers. Nonwovens of synthetic polymers
with an improved binding composition are disclosed in EP 2 465 986
A1. WO 97/30199 relates to fibers or filaments suitable for the
production of a nonwoven fabric, the fibers or filaments consisting
essentially of a polyolefin and inorganic particles.
[0006] In view of the foregoing, improving the properties of
polyester based nonwoven fabrics remains of interest to the skilled
man.
[0007] It is an object of the present invention to provide a
nonwoven fabric having an improved soft touch and a higher
stiffness. It would also be desirable to provide a nonwoven fabric
which can be tailored with respect to its hydrophobic or
hydrophilic properties. It would also be desirable to provide a
nonwoven fabric containing a reduced amount of polymer without
affecting the quality of the nonwoven fabric significantly.
[0008] It also an object of the present invention to provide a
process for producing a nonwoven fabric from a polyester based
polymer composition, especially a PET composition, which allows
short cycle times during melt processing. It is also desirable to
provide a process for producing a nonwoven fabric which allows the
use of recycled polyester, especially recycled PET.
[0009] The foregoing objects and other objects are solved by the
subject-matter as defined herein in the independent claims.
[0010] According to one aspect of the present invention, a nonwoven
fabric comprising at least one polymer comprising a polyester, and
at least one filler comprising calcium carbonate is provided.
[0011] According to another aspect, the present invention provides
a process for producing a nonwoven fabric comprising the steps of
[0012] a) providing a mixture of at least one polymer comprising a
polyester and at least one filler comprising calcium carbonate,
[0013] b) forming the mixture into fibers, filaments and/or
film-like filamentary structures, and [0014] c) forming a nonwoven
fabric from the fibers, filaments and/or film-like filamentary
structures.
[0015] According to still another aspect, the present invention
provides an article comprising the inventive nonwoven fabric,
wherein said article is selected from construction products,
consumer apparel, industrial apparel, medical products, home
furnishings, protective products, packaging materials, cosmetic
products, hygiene products, or filtration materials.
[0016] According to still another aspect, the present invention
provides the use of calcium carbonate as filler in a nonwoven
fabric comprising at least one polymer comprising a polyester.
[0017] According to still another aspect, the present invention
provides the use of fibers for the manufacture of a non-woven
fabric, wherein the fibers comprise at least one polymer comprising
a polyester and at least one filler comprising calcium
carbonate.
[0018] According to still another aspect, the present invention
provides the use of the inventive nonwoven fabric in construction
products, waterproofing, thermal insulation, soundproofing,
roofing, consumer apparel, upholstery and clothing industries,
industrial apparel, medical products, home furnishings, protective
products, packaging materials, cosmetic products, hygiene products,
or filtration materials.
[0019] Advantageous embodiments of the present invention are
defined in the corresponding sub-claims.
[0020] According to one embodiment the polyester is selected from
the group consisting of a polyglycolic acid, a polycaprolactone, a
polyethylene adipate, a polyhydroxyalkanoate, a
polyhydroxybutyrate, a polyethylene terephthalate, a
polytrimethylene terephthalate, a polybutylene terephthalate, a
polyethylene naphthalate, a polylactic acid, or a mixture thereof,
or copolymers thereof, preferably the polyester is a polyethylene
terephthalate. According to another embodiment the polyester has a
number average molecular weight from 5000 to 100000 g/mol,
preferably from 10000 to 50000 g/mol, and more preferably from
15000 to 20000 g/mol.
[0021] According to one embodiment the calcium carbonate is ground
calcium carbonate, precipitated calcium carbonate, modified calcium
carbonate, surface-treated calcium carbonate, or a mixture thereof,
preferably surface-treated calcium carbonate. According to another
embodiment the calcium carbonate has an average particle size
d.sub.50 from 0.1 to 3 .mu.m, preferably from 0.4 to 2.5 .mu.m,
more preferably from 1.0 to 2.3 .mu.m, and most preferably from 1.2
to 1.8 .mu.m. According to still another embodiment the calcium
carbonate has an top cut particle size d.sub.98 from 1 to 10 .mu.m,
preferably from 5 to 8 .mu.m, more preferably from 4 to 7 .mu.m,
and most preferably from 6 to 7 .mu.m. According to still another
embodiment the calcium carbonate is present in the nonwoven fabric
in an amount from 0.1 to 50 wt.-%, preferably from 0.2 to 40 wt.-%,
and more preferably from 1 to 35 wt.-%, based on the total weight
of the nonwoven fabric.
[0022] According to one embodiment of the inventive process, in
step b) the mixture is formed into fibers, preferably by an
extrusion process, and more preferably by a melt blown process, a
spunbond process, or a combination thereof. According to another
embodiment of the inventive process, the nonwoven fabric is formed
by collecting the fibers on a surface or carrier. According to
still another embodiment of the inventive process, steps b) and c)
are repeated two or more times to produce a multilayer nonwoven
fabric, preferably a spundbonded-meltblown-spunbonded (SMS), a
meltblown-spunbonded-meltblown (MSM), a
spundbonded-meltblown-spunbonded-meltblown (SMSM), a
meltblown-spunbonded-meltblown-spunbonded (MSMS), a
spundbonded-meltblown-meltblown-spunbonded (SMMS), or a
meltblown-spunbonded-spunbonded-meltblown (MSSM) nonwoven
fabric.
[0023] It should be understood that for the purpose of the present
invention, the following terms have the following meaning:
[0024] The term "degree of crystallinity" as used in the context of
the present invention refers to the fraction of the ordered
molecules in a polymer. The remaining fraction is designated as
"amorphous". Polymers may crystallize upon cooling from the melt,
mechanical stretching or solvent evaporation. Crystalline areas are
generally more densely packed than amorphous areas and
crystallization may affect optical, mechanical, thermal and
chemical properties of the polymer. The degree of crystallinity is
specified in percent and can be determined by differential scanning
calorimetry (DSC).
[0025] "Ground calcium carbonate" (GCC) in the meaning of the
present invention is a calcium carbonate obtained from natural
sources, such as limestone, marble, calcite or chalk, and processed
through a wet and/or dry treatment such as grinding, screening
and/or fractionation, for example by a cyclone or classifier.
[0026] The term "intrinsic viscosity" as used in the context of the
present invention is a measure of the capability of a polymer in
solution to enhance the viscosity of the solution and is specified
in dl/g.
[0027] "Modified calcium carbonate" (MCC) in the meaning of the
present invention may feature a natural ground or precipitated
calcium carbonate with an internal structure modification or a
surface-reaction product, i.e. "surface-reacted calcium carbonate".
A "surface-reacted calcium carbonate" is a material comprising
calcium carbonate and insoluble, preferably at least partially
crystalline, calcium salts of anions of acids on the surface.
Preferably, the insoluble calcium salt extends from the surface of
at least a part of the calcium carbonate. The calcium ions forming
said at least partially crystalline calcium salt of said anion
originate largely from the starting calcium carbonate material.
MCCs are described, for example, in US 2012/0031576 A1, WO
2009/074492 A1, EP 2 264 109 A1, EP 2 070 991 A1, or 2 264 108
A1.
[0028] For the purpose of the present invention, the term "nonwoven
fabric" refers to a flat, flexible, porous sheet structure that is
produced by interlocking layers or networks of fibers, filaments,
or film-like filamentary structures.
[0029] Throughout the present document, the "particle size" of a
calcium carbonate filler is described by its distribution of
particle sizes. The value d.sub.x represents the diameter relative
to which x % by weight of the particles have diameters less than
d.sub.x. This means that the d.sub.20 value is the particle size at
which 20 wt.-% of all particles are smaller, and the d.sub.98 value
is the particle size at which 98 wt.-% of all particles are
smaller. The d.sub.98 value is also designated as "top cut". The
d.sub.50 value is thus the weight median particle size, i.e. 50
wt.-% of all grains are bigger or smaller than this particle size.
For the purpose of the present invention the particle size is
specified as weight median particle size d.sub.50 unless indicated
otherwise. For determining the weight median particle size d.sub.50
value or the top cut particle size d.sub.98 value a Sedigraph 5100
or 5120 device from the company Micromeritics, USA, can be
used.
[0030] As used herein the term "polymer" generally includes
homopolymers and co-polymers such as, for example, block, graft,
random and alternating copolymers, as well as blends and
modifications thereof.
[0031] "Precipitated calcium carbonate" (PCC) in the meaning of the
present invention is a synthesized material, generally obtained by
precipitation following a reaction of carbon dioxide and calcium
hydroxide (hydrated lime) in an aqueous environment or by
precipitation of a calcium- and a carbonate source in water.
Additionally, precipitated calcium carbonate can also be the
product of introducing calcium and carbonate salts, calcium
chloride and sodium carbonate for example, in an aqueous
environment. PCC may be vaterite, calcite or aragonite. PCCs are
described, for example, in EP 2 447 213 A1, EP 2,524,898 A1, EP 2
371 766 A1, or unpublished European patent application no. 12 164
041.1.
[0032] In the meaning of the present invention, a "surface-treated
calcium carbonate" is a ground, precipitated or modified calcium
carbonate comprising a treatment or coating layer, e.g. a layer of
fatty acids, surfactants, siloxanes, or polymers.
[0033] Where the term "comprising" is used in the present
description and claims, it does not exclude other elements. For the
purposes of the present invention, the term "consisting of" is
considered to be a preferred embodiment of the term "comprising
of". If hereinafter a group is defined to comprise at least a
certain number of embodiments, this is also to be understood to
disclose a group, which preferably consists only of these
embodiments.
[0034] Where an indefinite or definite article is used when
referring to a singular noun, e.g. "a", "an" or "the", this
includes a plural of that noun unless something else is
specifically stated.
[0035] Terms like "obtainable" or "definable" and "obtained" or
"defined" are used interchangeably. This e.g. means that, unless
the context clearly dictates otherwise, the term "obtained" does
not mean to indicate that e.g. an embodiment must be obtained by
e.g. the sequence of steps following the term "obtained" even
though such a limited understanding is always included by the terms
"obtained" or "defined" as a preferred embodiment.
[0036] The inventive nonwoven fabric comprises at least one polymer
comprising a polyester and at least one filler comprising calcium
carbonate. In the following details and preferred embodiments of
the inventive product will be set out in more detail. It is to be
understood that these technical details and embodiments also apply
to the inventive process for producing said nonwoven fabric and the
inventive use of the nonwoven fabric, fibers, compositions, and
calcium carbonate.
[0037] The at Least One Polymer
[0038] The nonwoven fabric of the present invention comprises at
least one polymer comprising a polyester.
[0039] Polyesters are a class of polymers which contain the ester
functional group in their main chain and are generally obtained by
a polycondensation reaction. Polyesters may include naturally
occurring polymers such as cutin as well as synthetic polymers such
as polycarbonate or poly butyrate. Depending on their structure
polyesters may be biodegradable.
[0040] According to one embodiment, the polyester is selected form
the group consisting of a polyglycolic acid, a polycaprolactone, a
polyethylene adipate, a polyhydroxyalkanoate, a
polyhydroxybutyrate, a polyethylene terephthalate, a
polytrimethylene terephthalate, a polybutylene terephthalate, a
polyethylene naphthalate, a polylactic acid, or a mixture thereof,
or copolymers thereof. Any of these polymers may be in pure form,
i.e. in form of a homopolymer, or may be modified by
copolymerization and/or by adding one or more substituents to the
main chain or side chains of the main chain.
[0041] According to one embodiment of the present invention, the at
least one polymer consists of a polyester. The polyester may
consist of only one specific type of polyester or a mixture of one
or more types of polyesters.
[0042] The at least one polymer can be present in the nonwoven
fabric in an amount of at least 40 wt.-%, preferably of at least 60
wt.-%, more preferably of at least 80 wt.-%, and most preferably of
at least 90 wt.-%, based on the total weight of the nonwoven
fabric. According to one embodiment, the at least one polymer is
present in the nonwoven fabric in an amount from 50 to 99 wt.-%,
preferably from 60 to 98 wt.-%, and more preferably from 65 to 95
wt.-%, based on the total weight of the nonwoven fabric.
[0043] According to a preferred embodiment of the present
invention, the polyester is a polyethylene terephthalate.
[0044] Polyethylene terephthalate (PET) is a condensation polymer
and may be industrially produced by condensating either
terephthalic acid or dimethyl terephthalate with ethylene
glycol.
[0045] PET may be polymerized by ester interchange employing the
monomers diethyl terephthalate and ethylene glycol or direct
esterification by employing the monomers terephthalic acid and
ethylene glycol. Both ester interchange and direct esterification
processes are combined with polycondensation steps either
batch-wise or continuously. Batch-wise systems require two reaction
vessels; one for esterification or ester interchange and one for
polymerization. Continuous systems require at least three vessels;
one for esterification or ester interchange, another for reducing
excess glycols, and still another for polymerization.
[0046] Alternatively, PET may be produced by solid-phase
polycondensation. For example, in such a process a melt
polycondensation is continued until the pre-polymer has an
intrinsic viscosity of 1.0 to 1.4 dl/g, at which point the polymer
is cast into a solid film.
[0047] The pre-crystallization is carried out by heating, e.g.
above 200.degree. C., until the desirable molecular weight of the
polymer is obtained.
[0048] According to one embodiment, PET is obtained from a
continuous polymerization process, a batch-wise polymerization
process or a solid phase polymerization process.
[0049] According to the present invention, the term "polyethylene
terephthalate" comprises unmodified and modified polyethylene
terephthalate. The polyethylene terephthalate may be a linear
polymer, a branched polymer, or a cross-linked polymer. For
example, if glycerol is allowed to react with a diacid or its
anhydride each glycerol will generate a branch point. If internal
coupling occurs, for example, by reaction of a hydroxyl group and
an acid function from branches at the same or a different molecule,
the polymer will become crosslinked. Optionally, the polyethylene
terephthalate can be substituted, preferably with a C.sub.1 to
C.sub.10 alkyl group, a hydroxyl, and/or an amine group. According
to one embodiment, the polyethylene terephthalate is substituted
with a methyl, ethyl, propyl, butyl, tert.-butyl, hydroxyl and/or
amine group. The polyethylene terephthalate can also be modified by
co-polymerization, e.g, with cyclohexane dimethanol or isophthalic
acid.
[0050] Depending on its processing and thermal history, PET may
exist both as an amorphous and as a semi-crystalline polymer, i.e.
as a polymer comprising crystalline and amorphous fractions. The
semi-crystalline material can appear transparent or opaque and
white depending on its crystal structure and particle size.
[0051] According to one embodiment, the polyethylene terephthalate
is amorphous. According to another embodiment, the polyethylene
terephthalate is semi-crystalline, preferably the polyethylene
terephthalate has a degree of crystallinity of at least 20%, more
preferably of at least 40%, and most preferably of at least 50%.
According to still another embodiment, the polyethylene
terephthalate has a degree of crystallinity from 10 to 80%, more
preferably from 20 to 70%, and most preferably from 30 to 60%. The
degree of crystallinity may be measured with differential scanning
calorimetry (DSC).
[0052] According to one embodiment of the present invention, the
polyethylene terephthalate has an intrinsic viscosity, IV, from 0.3
to 2.0 dl/g, preferably from 0.5 to 1.5 dl/g, and more preferably
from 0.7 to 1.0 dl/g.
[0053] According to another embodiment of the present invention,
the polyethylene terephthalate has a glass transition temperature,
T.sub.g, from 50 to 200.degree. C., preferably from 60 to
180.degree. C., and more preferably from 70 to 170.degree. C.
[0054] According to one embodiment of the present invention, the
polyethylene terephthalate has a number average molecular weight
from 5000 to 100000 g/mol, preferably from 10000 to 50000 g/mol,
and more preferably from 15000 to 20000 g/mol.
[0055] The polyethylene terephthalate may be a virgin polymer, a
recycled polymer, or a mixture thereof. A recycled polyethylene
terephthalate may be obtained from post consumed PET bottles,
preform PET scrap, regrained PET, or reclaimed PET.
[0056] According to one embodiment, the polyethylene terephthalate
includes 10 wt.-%, preferably 25 wt.-%, more preferably 50 wt.-%,
and most preferably 75 wt.-% recycled PET, based on the total
amount of polyethylene terephthalate.
[0057] According to one embodiment, the at least one polymer
consists of a polyethylene terephthalate. The PET may consist of
only one specific type of PET or a mixture of two or more types of
PET.
[0058] According to one embodiment, the at least one polymer
comprises further polymers, preferably polyolefines, polyamides,
cellulose, polybenzimidazols, or mixtures thereof, or copolymers
thereof. Examples for such polymers are polyhexamethylene
diadipamide, polycaprolactam, aromatic or partially aromatic
polyamides ("aramids"), nylon, polyphenylene sulfide (PPS),
polyethylene, polypropylene, polybenzimidazols, or rayon.
[0059] According to one embodiment, the at least one polymer
comprises at least 50 wt.-%, preferably at least 75 wt.-%, more
preferably at least 90 wt.-%, and most preferably at least 95 wt.-%
of a polyethylene terephthalate, based on the total amount of the
at least one polymer.
[0060] The at Least One Filler
[0061] According to the present invention, the nonwoven fabric
comprises at least one filler comprising a calcium carbonate. The
at least one filler is dispersed within the at least one
polymer.
[0062] The use of at least one filler comprising calcium carbonate
in polyester-based nonwoven fabrics has certain advantages compared
to conventional nonwoven fabrics. For example, the hydrophobic or
hydrophilic properties of the nonwoven web can be adapted to the
intended application by using an appropriate calcium carbonate
filler. Furthermore, the use of calcium carbonate fillers allows
for the reduction of polyesters in the production of nonwoven
fabrics without affecting the quality of the nonwoven
significantly. Moreover, the inventors surprisingly found that if
calcium carbonate is added as filler to PET, the polymer exhibits a
higher thermal conductivity, which leads to a faster cooling rate
of the polymer. Furthermore, without being bound to any theory it
is believed that calcium carbonate acts as nucleating agent for
PET, and thus, increases the crystallization temperature of PET. As
a result the crystallization rate is increased, which, for example,
allows shorter cycling times during melt processing. The inventors
also found that nonwoven webs manufactured from PET including
calcium carbonate fillers have an improved soft touch and a higher
stiffness compared to nonwoven webs made from PET only.
[0063] According to one embodiment, the calcium carbonate is ground
calcium carbonate, precipitated calcium carbonate, modified calcium
carbonate, surface-treated calcium carbonate, or a mixture thereof.
Preferably the calcium carbonate is surface-treated calcium
carbonate.
[0064] Ground (or natural) calcium carbonate (GCC) is understood to
be a naturally occurring form of calcium carbonate, mined from
sedimentary rocks such as limestone or chalk, or from metamorphic
marble rocks. Calcium carbonate is known to exist as three types of
crystal polymorphs: calcite, aragonite and vaterite. Calcite, the
most common crystal polymorph, is considered to be the most stable
crystal form of calcium carbonate. Less common is aragonite, which
has a discrete or clustered needle orthorhombic crystal structure.
Vaterite is the rarest calcium carbonate polymorph and is generally
unstable. Ground calcium carbonate is almost exclusively of the
calcitic polymorph, which is said to be trigonal-rhombohedral and
represents the most stable of the calcium carbonate polymorphs. The
term "source" of the calcium carbonate in the meaning of the
present application refers to the naturally occurring mineral
material from which the calcium carbonate is obtained. The source
of the calcium carbonate may comprise further naturally occurring
components such as magnesium carbonate, alumino silicate etc.
[0065] According to one embodiment of the present invention the
source of ground calcium carbonate (GCC) is selected from marble,
chalk, calcite, dolomite, limestone, or mixtures thereof.
Preferably, the source of ground calcium carbonate is selected from
marble. According to one embodiment of the present invention the
GCC is obtained by dry grinding. According to another embodiment of
the present invention the GCC is obtained by wet grinding and
subsequent drying.
[0066] "Precipitated calcium carbonate" (PCC) in the meaning of the
present invention is a synthesized material, generally obtained by
precipitation following reaction of carbon dioxide and lime in an
aqueous environment or by precipitation of a calcium and carbonate
ion source in water or by precipitation of calcium and carbonate
ions, for example CaCl.sub.2 and Na.sub.2CO.sub.3, out of solution.
Further possible ways of producing PCC are the lime soda process,
or the Solvay process in which PCC is a by-product of ammonia
production. Precipitated calcium carbonate exists in three primary
crystalline forms: calcite, aragonite and vaterite, and there are
many different polymorphs (crystal habits) for each of these
crystalline forms. Calcite has a trigonal structure with typical
crystal habits such as scalenohedral (S-PCC), rhombohedral (R-PCC),
hexagonal prismatic, pinacoidal, colloidal (C-PCC), cubic, and
prismatic (P-PCC). Aragonite is an orthorhombic structure with
typical crystal habits of twinned hexagonal prismatic crystals, as
well as a diverse assortment of thin elongated prismatic, curved
bladed, steep pyramidal, chisel shaped crystals, branching tree,
and coral or worm-like form. Vaterite belongs to the hexagonal
crystal system. The obtained PCC slurry can be mechanically
dewatered and dried.
[0067] According to one embodiment of the present invention, the
calcium carbonate comprises one precipitated calcium carbonate.
According to another embodiment of the present invention, the
calcium carbonate comprises a mixture of two or more precipitated
calcium carbonates selected from different crystalline forms and
different polymorphs of precipitated calcium carbonate. For
example, the at least one precipitated calcium carbonate may
comprise one PCC selected from S-PCC and one PCC selected from
R-PCC.
[0068] A modified calcium carbonate may feature a GCC or PCC with
an internal structure modification or a surface-reacted GCC or PCC.
A surface-reacted calcium carbonate may be prepared by providing a
GCC or PCC in form of an aqueous suspension, and adding an acid to
said suspension. Suitable acids are, for example, sulphuric acid,
hydrochloric acid, phosphoric acid, citric acid, oxalic acid, or a
mixture thereof. In a next step, the calcium carbonate is treated
with gaseous carbon dioxide. If a strong acid such as sulphuric
acid or hydrochloric acid is used for the acid treatment step, the
carbon dioxide will form automatically in situ. Alternatively or
additionally, the carbon dioxide can be supplied from an external
source. Surface-reacted calcium carbonates are described, for
example, in US 2012/0031576 A1, WO 2009/074492 A1, EP 2 264 109 A1,
EP 2 070 991 A1, or EP 2 264 108 A1.
[0069] A surface-treated calcium carbonate may feature a GCC, PCC,
or MCC comprising a treatment or coating layer on its surface. For
example, the calcium carbonate may be treated or coated with a
hydrophobising surface treatment agent such as, e.g., aliphatic
carboxylic acids, salts or esters thereof, or a siloxane. Suitable
aliphatic acids are, for example, C.sub.5 to C.sub.28 fatty acids
such as stearic acid, palmitic acid, myristic acid, lauric acid, or
a mixture thereof. The calcium carbonate may also be treated or
coated to become cationic or anionic with, for example, a
polyacrylate or polydiallyldimethylammonium chloride (polyDADMAC).
Surface-treated calcium carbonates are, for example, described in
EP 2 159 258 A1.
[0070] According to one embodiment, the modified calcium carbonate
is a surface-reacted calcium carbonate, preferably obtained from
the reaction with sulphuric acid, hydrochloric acid, phosphoric
acid, citric acid, oxalic acid, or a mixture thereof, and carbon
dioxide.
[0071] According to another embodiment, the surface-treated calcium
carbonate comprises a treatment layer or surface coating obtained
from the treatment with fatty acids, their salts, their esters, or
combinations thereof, preferably from the treatment with aliphatic
C.sub.5 to C.sub.28 fatty acids, their salts, their esters, or
combinations thereof, and more preferably from the treatment with
ammonium stearate, calcium stearate, stearic acid, palmitic acid,
myristic acid, lauric acid, or mixtures thereof.
[0072] According to one embodiment, the calcium carbonate has an
average particle size d.sub.50 from 0.1 to 3 .mu.m, preferably from
0.4 to 2.5 .mu.m, more preferably from 1.0 to 2.3 .mu.m, and most
preferably from 1.2 to 1.8 .mu.m. In addition or alternatively, the
calcium carbonate has an top cut particle size d.sub.98 from 1 to
10 .mu.m, preferably from 5 to 8 .mu.m, more preferably from 4 to 7
.mu.m, and most preferably from 6 to 7 .mu.m.
[0073] The calcium carbonate can be present in the nonwoven fabric
in an amount from 0.1 to 50 wt.-%, preferably from 0.2 to 40 wt.-%,
and more preferably from 1.0 to 35 wt.-%, based on the total weight
of the nonwoven fabric. According to another embodiment, the
calcium carbonate is present in the nonwoven fabric in an amount
from 0.5 to 20 wt.-%, from 1.0 to 10 wt.-%, from 5.0 to 40 wt.-%,
from 7.5 to 30 wt.-%, or from 10 to 25 wt.-%, based on the total
weight of the nonwoven fabric.
[0074] According to one embodiment, the calcium carbonate is
dispersed within the at least one polymer and is present in an
amount from 0.1 to 50 wt.-%, preferably from 0.2 to 40 wt.-%, and
more preferably from 1 to 35 wt.-%, based on the total weight of
the at least one polymer. According to another embodiment, the
calcium carbonate is dispersed within the at least one polymer and
is present in an amount from 0.5 to 20 wt.-%, from 1.0 to 10 wt.-%,
from 5.0 to 40 wt.-%, from 7.5 to 30 wt.-%, or from 10 to 25 wt.-%,
based on the total weight of the at least one polymer.
[0075] According to one embodiment, the at least one filler
consists of calcium carbonate. The calcium carbonate may consist of
only one specific type of calcium carbonate or a mixture of two or
more types of calcium carbonates.
[0076] According to another embodiment, the at least one filler
comprises further mineral pigments. Examples for further pigment
particles comprise silica, alumina, titanium dioxide, clay,
calcined clays, talc, kaolin, calcium sulphate, wollastonite, mica,
bentonite, barium sulfate, gypsum, or zinc oxide.
[0077] According to one embodiment, the at least one filler
comprises at least 50 wt.-%, preferably at least 75 wt.-%, more
preferably at least 90 wt.-%, and most preferably at least 95 wt.-%
calcium carbonate, based on the total amount of the at least one
filler.
[0078] According to one embodiment, the at least one filler is
present in the nonwoven fabric in an amount from 0.1 to 50 wt.-%,
preferably from 0.2 to 40 wt.-%, and more preferably from 1 to 35
wt.-%, based on the total weight of the nonwoven fabric.
[0079] According to another embodiment, the at least one filler is
dispersed within the at least one polymer and is present in an
amount from 1 to 50 wt.-%, preferably from 2 to 40 wt.-%, and more
preferably from 5 to 35 wt.-%, based on the total weight of the at
least one polymer.
[0080] According to one aspect of the present invention, the use of
calcium carbonate as filler in a nonwoven fabric comprising at
least one polymer comprising a polyester is provided. According to
another aspect of the present invention, the use of calcium
carbonate as filler in a nonwoven fabric is provided, wherein the
filler is dispersed within at least one polymer comprising a
polyester.
[0081] According to one preferred embodiment of the present
invention, the use of calcium carbonate as filler in a nonwoven
fabric comprising a polyethylene terephthalate is provided.
According to another preferred embodiment of the present invention,
the use of calcium carbonate as filler in a nonwoven fabric is
provided, wherein the filler is dispersed within at least one
polymer comprising a polyethylene terephthalate. Preferably, the
calcium carbonate is a surface-treated calcium carbonate.
[0082] According to a further aspect of the present invention, the
use of calcium carbonate as filler in a nonwoven fabric fiber,
filament and/or film-like filamentary structure comprising at least
one polymer comprising a polyester, preferably a polyethylene
terephthalate, is provided. According to a further aspect of the
present invention, the use of calcium carbonate as filler in a
nonwoven fabric fiber, filament and/or film-like filamentary
structure comprising at least one polymer comprising a polyester,
preferably a polyethylene terephthalate, is provided, wherein the
filler is dispersed within at least one polymer.
[0083] The Nonwoven Fabric
[0084] A nonwoven fabric is a flat, flexible, porous sheet
structure that is produced by interlocking layers or networks of
fibers, filaments and/or film-like filamentary structures.
[0085] According one aspect of the present invention a nonwoven
fabric fiber, filament and/or film-like filamentary structure
comprising at least one polymer comprising a polyester and at least
one filler comprising calcium carbonate is provided.
[0086] According to one embodiment, the nonwoven fabric comprises
at least one polymer comprising a polyester and at least one filler
comprising calcium carbonate, wherein the at least one filler is
dispersed within the at least one polymer. According to another
embodiment the nonwoven fabric comprises the at least one polymer
and the at least one filler in form of fibers, filaments and/or
film-like filamentary structures, wherein the at least one filler
is dispersed within the at least one polymer.
[0087] The fibers and/or filaments may have a diameter from 0.5 to
40 .mu.m, preferably from 5 to 35 .mu.m. Furthermore, the fibers
and/or filaments can have any cross-section shape, e.g., a
circular, oval, rectangular, dumpbell-shaped, kidney-shaped,
triangular, or irregular. The fibers and/or filaments can also be
hollow and/or bi-component and/or tri-component fibers.
[0088] In addition to the at least one polymer and the at least one
filler, the nonwoven fabric may comprise further additives, for
example, waxes, optical brighteners, heat stabilizers,
antioxidants, anti-static agents, anti-blocking agents, dyestuffs,
pigments, luster improving agents, surfactants, natural oils, or
synthetic oils. The nonwoven fabric may also comprise further
inorganic fibers, preferably glass fibers, carbon fibers, or metal
fibers. Alternatively or additionally, natural fibers such as
cotton, linen, silk, or wool may be added. The nonwoven fabric may
also be reinforced by reinforcement threads in form of a textile
surface structure, preferably in form of a fabric, laying, knitted
fabric, knitwear or nonwoven fabric.
[0089] According to one embodiment, the nonwoven fabric consists of
the at least one polymer comprising a polyester and the at least
one filler comprising calcium carbonate.
[0090] According to another embodiment, the nonwoven fabric
comprises at least one polymer comprising a polyethylene
terephthalate and at least one filler comprising calcium carbonate.
According to still another embodiment, the nonwoven fabric consists
of a polyethylene terephthalate and calcium carbonate.
[0091] According to an exemplary embodiment, the nonwoven fabric
comprises the at least one polymer in an amount from 50 to 99
wt.-%, and the at least one filler in an amount from 1 to 50 wt.-%,
based on the total weight of the nonwoven fabric, preferably the at
least one polymer in an amount from 60 to 98 wt.-%, and the at
least one filler in an amount from 2 to 40 wt.-%, and more
preferably the at least one polymer in an amount from 65 to 95
wt.-%, and the at least one filler in an amount from 5 to 35 wt.-%.
According to another exemplary embodiment, the nonwoven fabric
consists of 90 wt.-% of a polyester, preferably a polyethylene
terephthalate, and 10 wt.-% calcium carbonate, preferably a ground
calcium carbonate, based on the total weight of the nonwoven
fabric. According to still another exemplary embodiment, the
nonwoven fabric consists of 80 wt.-% of a polyester, preferably a
polyethylene terephthalate, and 20 wt.-% calcium carbonate,
preferably a ground calcium carbonate, based on the total weight of
the nonwoven fabric.
[0092] According to one aspect of the present invention, a process
for producing a nonwoven fabric is provided comprising the steps of
[0093] a) providing a mixture of at least one polymer comprising a
polyester and at least one filler comprising calcium carbonate,
[0094] b) forming the mixture into fibers, filaments and/or
film-like filamentary structures, and [0095] c) forming a nonwoven
fabric from the fibers, filaments and/or film-like filamentary
structures.
[0096] According to a preferred embodiment, the polyester is a
polyethylene terephthalate and/or the calcium carbonate is
surface-treated calcium carbonate.
[0097] The mixture of the at least one polymer comprising a
polyethylene terephthalate and at the least one filler comprising
calcium carbonate provided in process step a) can be prepared by
any method known in the art. For example, the at least one polymer
and the at least one filler may be dry blended, melt blended and
optionally formed into granulates or pellets, or a masterbatch of
the at least one polymer and the at least one filler may be
premixed, optionally formed into granulates or pellets, and mixed
with additional polymer or filler.
[0098] According to one embodiment, in step b) the mixture is
formed into fibers, preferably by an extrusion process, and more
preferably by a melt blown process, a spunbond process, or a
combination thereof. However, any other suitable process known in
the art for forming polymers into fibers may also be used.
[0099] Any melt blown process, spunbond process, or a combination
thereof, known in the art may be employed to form the mixture of at
least one polymer and at least one filler into fibers. For example,
melt blown fibers may be produced by melting the mixture, extruding
the mixture through a die or small orifices to form fibers, and
attenuating the molten polymer fibers by hot air. Surrounding cool
air can then be induced into the hot air stream for cooling and
solidifying the fibers. In a spundbond process, the mixture can be
melt-spun into fibers by pumping the molten mixture through a
multitude of capillaries arranged in a uniform array of columns and
rows. After extrusion, the fibers can be attenuated by high
velocity air. The air creates a draw force on the fibers that draws
them down to a desired denier. The spunbond process may have the
advantage of giving nonwovens greater strength. A second component
may be co-extruded in the spunbond process, which may provide extra
properties or bonding capabilities.
[0100] Two typical spunbond processes are known in the art as the
Lurgi process and the Reifenhauser process. The Lurgi process is
based on the extrusion of molten polymer through spinneret orifices
followed by the newly formed extruded filaments being quenched with
air and drawn by suction through Venturi tubes. Subsequent to
formation, the filaments are disbursed on a conveyor belt to form a
nonwoven web. The Reifenhauser process differs from the Lurgi
process in that the quenching area for the filaments is sealed, and
the quenched air stream is accelerated, thus inducing more
effective entrainment of the filaments into the air stream.
[0101] The fibers formed in process step b) may be drawn or
elongated to induce molecular orientation and affect crystallinity.
This may result in a reduction in diameter and an improvement in
physical properties.
[0102] According to one embodiment of the present invention, in
step b) the mixture is formed into fibers by combining a melt blown
process and a spunbond process.
[0103] By combining a meltblown and a spunbond process, a
multilayer nonwoven fabric can be produced, for example, a nonwoven
fabric comprising two outer layers of spunbond fabric and an inner
layer of meltblown fabric, which is known in the art as
spundbonded-meltblown-spunbonded (SMS) nonwoven fabric.
Additionally either or both of these processes may be combined in
any arrangement with a staple fiber carding process or bonded
fabrics resulting from a nonwoven staple fiber carding process. In
such described laminate fabrics, the layers are generally at least
partially consolidated by one of the optional bonding methods
described further below.
[0104] The nonwoven fabric produced by the inventive process can be
a multilayered nonwoven fabric, preferably a
spundbonded-meltblown-spunbonded (SMS), a
meltblown-spunbonded-meltblown (MSM), a
spundbonded-meltblown-spunbonded-meltblown (SMSM), a
meltblown-spunbonded-meltblown-spunbonded (MSMS), a
spundbonded-meltblown-meltblown-spunbonded (SMMS), or a
meltblown-spunbonded-spunbonded-meltblown (MSSM) nonwoven fabric.
Said nonwoven fabric may be compressed in order to ensure the
cohesion of the layers, for example, by lamination.
[0105] According to one embodiment, steps b) and c) of the
inventive process are repeated two or more times to produce a
multilayer nonwoven fabric, preferably a
spundbonded-meltblown-spunbonded (SMS), a
meltblown-spunbonded-meltblown (MSM), a
spundbonded-meltblown-spunbonded-meltblown (SMSM), a
meltblown-spunbonded-meltblown-spunbonded (MSMS), a
spundbonded-meltblown-meltblown-spunbonded (SMMS), or a
meltblown-spunbonded-spunbonded-meltblown (MSSM) nonwoven
fabric.
[0106] According to one embodiment, in step c) the nonwoven fabric
is formed by collecting the fibers on a surface or carrier. For
example, the fibers can be collected on a foraminous surface such
as a moving screen or a forming wire. The fibers may be randomly
deposited on the foraminous surface so as to form a sheet, which
may be held on the surface by a vacuum force.
[0107] According to an optional embodiment of the inventive
process, the obtained nonwoven fabric is subjected to a bonding
step. Examples of bonding methods include thermal point bonding or
calendering, ultrasonic bonding, hydroentanglement, needling and
through-air bonding. Thermal point bonding or calendering is a
commonly used method and involves passing nonwoven fabric to be
bonded through a heated calender roll and an anvil roll. The
calender roll is usually patterned in some way so that the entire
fabric is not bonded across its entire surface. Various patterns
can be used in the process of the present invention without
affecting the mechanical properties of the web. For instance, the
web can be bonded according to a ribbed knit pattern, a wire weave
pattern, a diamond pattern, and the like. However, any other
bonding method known in the art may also be used. Optionally,
binding agents, adhesives, or other chemicals may be added during
the binding step.
[0108] According to another optional embodiment of the inventive
process, the obtained nonwoven fabric is subjected to a
post-treatment step. Examples for post-treatment processes are
direction orientation, creping, hydroentanglement, or embossing
processes.
[0109] According to one aspect of the present invention the use of
fibers for the manufacture of a non-woven fabric is provided,
wherein the fibers comprise at least one polymer comprising a
polyester and at least one filler comprising calcium carbonate.
According to one preferred embodiment of the present invention the
use of fibers for the manufacture of a non-woven fabric is
provided, wherein the fibers comprise at least one polymer
comprising a polyethylene terephthalate and at least one filler
comprising calcium carbonate.
[0110] According to another aspect of the present invention the use
of a polymer composition for the manufacture of a non-woven fabric
is provided, wherein the polymer composition comprises at least one
polymer comprising a polyester and at least one filler comprising
calcium carbonate. According to another preferred embodiment of the
present invention the use of a polymer composition for the
manufacture of a non-woven fabric is provided, wherein the polymer
composition comprises at least one polymer comprising a
polyethylene terephthalate and at least one filler comprising
calcium carbonate.
[0111] The nonwoven fabric of the present invention can be used in
many different applications. According to one aspect of the present
invention, the inventive nonwoven fabric is used in construction
products, waterproofing, thermal insulation, soundproofing,
roofing, consumer apparel, upholstery and clothing industries,
industrial apparel, medical products, home furnishings, protective
products, packaging materials, cosmetic products, hygiene products,
or filtration materials. According to another aspect of the present
invention, an article comprising the inventive nonwoven fabric is
provided, wherein said article is selected from construction
products, consumer apparel, industrial apparel, medical products,
home furnishings, protective products, packaging materials,
cosmetic products, hygiene products, or filtration materials.
[0112] Examples for construction products are house wrap, asphalt
overlay, road and railroad beds, golf and tennis courts,
wallcovering backings, acoustical wall coverings, roofing materials
and tile underlayment, soil stabilizers and roadway underlayment,
foundation stabilizers, erosion control products, canals
construction, drainage systems, geomembranes protection and frost
protection products, agriculture mulch, pond and canal water
barriers, or sand infiltration barriers for drainage tile. Other
examples for construction products are fixations or reinforcements
for earth fillings.
[0113] Examples for consumer apparel are interlinings, clothing and
glove insulation, bra and shoulder paddings, handbag components, or
shoe components. Examples for industrial apparel are tarps, tents,
or transportation (lumber, steel) wrappings.
[0114] Examples of medical products are protective clothing, face
masks, isolation gowns, surgical gowns, surgical drapes and covers,
surgical scrub suits, caps, sponges, dressings, wipes, orthopedic
padding, bandages, tapes, dental bibs, oxygenators, dialyzers,
filters for IV solutions or blood, or transdermal drug delivery
components. Examples for home furnishings are pillows, cushions,
paddings in quilts or comforters, dust covers, insulators, window
treatments, blankets, drapery components, carpet backings, or
carpets.
[0115] Examples for protective products are coated fabrics,
reinforced plastic, protective clothing, lab coats, sorbents, or
flame barriers. Examples of packaging materials are desiccant
packing, sorbents packaging, gifts boxes, files boxes, various
nonwoven bags, book covers, mailing envelopes, express envelopes,
or courier bags. Examples of filtration materials are gasoline, oil
and air filters, including filtration liquid cartridge and bag
filters, vacuum bags, or laminates with non woven layers.
[0116] The scope and interest of the invention will be better
understood based on the following examples which are intended to
illustrate certain embodiments of the present invention and are
non-limitative.
EXAMPLES
1. Measurement Methods and Materials
[0117] In the following, measurement methods and materials
implemented in the examples are described.
[0118] Particle Size
[0119] The particle distribution of the calcium carbonate filler
was measured using a Sedigraph 5120 from the company Micromeritics,
USA. The method and the instruments are known to the skilled person
and are commonly used to determine grain size of fillers and
pigments. The measurement was carried out in an aqueous solution
comprising 0.1 wt.-% Na.sub.4P.sub.2O.sub.7. The samples were
dispersed using a high speed stirrer and supersonics.
[0120] Intrinsic Viscosity
[0121] The intrinsic viscosity or IV is a measure of the molecular
mass of the polymer and is measured by dilute solution
viscosimetry. All Ws were measured in 60/40 ratio by weight of
phenol/tetrachloroethane solution, at 25.degree. C. according to
ASTM D4603 in a Ubbelohde capillary viscometer. Typically, about
8-10 chips were dissolved to make a solution with a concentration
of about 0.5%.
[0122] Tensile Test
[0123] The tensile test was carried out in accordance with ISO
527-3 using a 1 BA (1:2) testing sample at a speed of 50 mm/min.
The properties that were determined via the tensile test are the
yield stress, the break-strain, the break-stress, and the e-modulus
of the polymer or polymer composition.
[0124] Charpy Impact Test
[0125] The charpy impact test was carried out in accordance with
ISO 179-2:1997(E) using notched and unnotched testing samples
having a size of 50.times.6.times.6 mm.
[0126] Materials [0127] Polymer 1: Lighter S98 PET, commercially
available from Equipolymers GmbH, Germany. [0128] Intrinsic
viscosity: 0.85.+-.0.02; T.sub.g: 78.degree. C.; T.sub.m:
247.degree. C.; crystallinity: min. 50. [0129] Polymer 2: Lighter
C93 PET, commercially available from Equipolymers GmbH, Germany.
[0130] Intrinsic viscosity: 0.80.+-.0.02; T.sub.g: 78.degree. C.;
T.sub.m: 247.degree. C.; crystallinity: min. 50. [0131] Filler:
Omyafilm 707-OG (ground calcium carbonate), commercially available
from Omya AG, Switzerland. [0132] Particle size d.sub.50: 1.6
.mu.m; top cut d.sub.98: 6 .mu.m.
2. Examples
Example 1
[0133] Testing samples containing polymer 1 only as well as a
composition of 90 wt.-% polymer 1 and 10 wt.-% filler, based on the
total weight of the composition, were prepared.
[0134] The mechanical properties of the testing samples were
determined using the tensile test described above at a tension of 5
N with a 500 N tester. The results of the tensile test are shown in
Table 1 below.
TABLE-US-00001 TABLE 1 Mechanical properties of samples A and B.
Sample A Sample B (comparative) (inventive) Amount polymer (wt.-%)
100 90 Amount filler (wt.-%) -- 10 Thickness (.mu.m) 206 205 Yield
stress (N/mm.sup.2) 55.9 58.8 Break-strain (%) 600 500 Break-stress
(N/mm.sup.2) 58.2 46.2 E-modulus (N/mm.sup.2) 10 064 11 125
[0135] The inventive sample B showed a higher yield stress and
e-modulus compared to the comparative sample A, while the
break-strain and break-stress of the inventive sample B was
reduced. Thus, the inventive polymer composition (sample B) had a
higher elasticity and softness compared to the pure PET polymer
(sample A). This has a positive effect on the haptic properties of
nonwoven fabrics produced from such a polymer composition,
especially with respect to the softness of the material. For
example, such a material is more pleasant to wear.
Example 2
[0136] Testing samples containing polymer 2 only as well as
compositions of 90 wt.-% polymer 2 and 10 wt.-% filler, and 80
wt.-% polymer 2 and 20 wt.-% filler, based on the total weight of
the composition, were prepared.
[0137] The mechanical properties of the testing samples were
determined using the tensile test described above at a tension of 4
N with a 20 kN tester and the Charpy impact test. The results of
the tensile test are shown in Table 2 below.
TABLE-US-00002 TABLE 2 Mechanical properties of samples C, D, and
E. Sample C Sample D Sample E (comparative) (inventive) (inventive)
Amount polymer (wt.-%) 100 90 80 Amount filler (wt.-%) -- 10 20
Thickness (mm) 2.09 2.08 2.09 Yield stress (N/mm.sup.2) 54.1 55.2
68.2 Break-strain (%) 830 578 242 Break-stress (N/mm.sup.2) ~60 ~50
~35 E-modulus (N/mm.sup.2) 2280 2640 3070 Charpy (kJ/m.sup.2)
notched 2.9 1.6 1.0 Charpy (kJ/m.sup.2) unnotched 150 72 62
[0138] The inventive samples D and E showed a higher yield stress
and e-modulus compared to the comparative sample C, while the
break-strain, the break-stress, and the impact resistance of the
inventive samples C and D was reduced. Thus, the inventive polymer
compositions (samples D and E) had a higher elasticity and softness
compared to the pure PET polymer (sample C). This has a positive
effect on the haptic properties of nonwoven fabrics produced from
such a polymer composition, especially with respect to the softness
of the material. For example, such a material is more pleasant to
wear.
* * * * *