U.S. patent application number 15/026602 was filed with the patent office on 2016-08-04 for fabric sheet with hig thermal stability.
The applicant listed for this patent is CARL FREUDENBERG KG. Invention is credited to Anke BOLD, Robert GROTEN, Gerald JARRE, Denis REIBEL, SungYong RYU.
Application Number | 20160222557 15/026602 |
Document ID | / |
Family ID | 51655682 |
Filed Date | 2016-08-04 |
United States Patent
Application |
20160222557 |
Kind Code |
A1 |
JARRE; Gerald ; et
al. |
August 4, 2016 |
FABRIC SHEET WITH HIG THERMAL STABILITY
Abstract
A fabric sheet, with low-cost production, has high thermal and
light stability, is recyclable, has a high mechanical load-bearing
capacity, and is elastically compliant, wherein the fabric sheet
has a main body composed of at least one ply, wherein the at least
one ply contains first fibers comprising a first polymer and second
fibers with a second polymer or wherein the at least one ply has
one and the same fibers that contain a first and a second polymer,
wherein a cold crystallization temperature of the first polymer
lies at the softening temperature of the second polymer or below
the softening temperature of the second polymer.
Inventors: |
JARRE; Gerald; (Weinheim,
DE) ; GROTEN; Robert; (Sundhoffen, FR) ; BOLD;
Anke; (Dirmstein, DE) ; RYU; SungYong;
(Jinsa-ri,Gongdo-myun;Ansung-si, KR) ; REIBEL; Denis;
(Herrlisheim, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CARL FREUDENBERG KG |
Weinheim |
|
DE |
|
|
Family ID: |
51655682 |
Appl. No.: |
15/026602 |
Filed: |
September 12, 2014 |
PCT Filed: |
September 12, 2014 |
PCT NO: |
PCT/EP2014/002469 |
371 Date: |
April 1, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D04H 3/147 20130101;
D04H 1/541 20130101; D04H 3/011 20130101; D04H 1/435 20130101; D01F
8/14 20130101 |
International
Class: |
D04H 1/435 20060101
D04H001/435; D04H 3/147 20060101 D04H003/147; D04H 3/011 20060101
D04H003/011 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 2, 2013 |
DE |
10 2013 016 293.9 |
Claims
1: A sheet product, comprising: a main body of at least one ply,
wherein the at least one ply comprises first fibers comprising a
first polymer and second fibers comprising a second polymer or
wherein the at least one ply comprises unitary fibers comprising
first and second polymers, wherein a cold crystallization
temperature of the first polymer is equal to the softening
temperature of the second polymer or below the softening
temperature of the second polymer.
2: The sheet product of claim 1, wherein the softening temperature
and/or the melting temperature of the second polymer is above the
softening temperature and/or the melting temperature of the first
polymer.
3: The sheet product of claim 1, wherein a difference between the
softening temperatures of the first and second polymers as measured
to DIN 53765 is at least 15.degree. C.
4: The sheet product of claim 2, wherein a difference between the
melting temperatures of the first and second polymers is at least
5.degree. C.
5: The sheet product of claim 1, wherein at least one of the
polymers is a polyester selected from the group consisting of
polyethylene terephthalate, polypropylene terephthalate,
polytetramethylene terephthalate, poly(decamethylene)
terephthalate, poly-1,4-cyclohexylene dimethyl terephthalate,
polybutylene terephthalate, polyethylene naphthalate, polyglycolic
acid, polylactides, polycaprolactones, polyethylene adipates,
polyhydroxyalkanoates, polyhydroxybutyrates,
poly-3-hydroxybutyrate-co-3-hydroxyvalerates, polytrimethylene
terephthalates, vectrans, polyethylene naphthalate, a copolymer of
two or more of any of these, or a mixture of two or more of any of
these.
6: The sheet product of claim 1, wherein the first polymer has a
cold crystallization temperature in a range of from 70 to
150.degree. C.
7: The sheet product of claim 1, wherein the second polymer has a
softening temperature in a range from 70 to 150.degree. C.
8: The sheet product of claim 1, wherein at least one fiber
comprises the first polymer and the second polymer, and wherein the
first polymer is in the form of at least one segment embedded in a
second polymer and/or at least partly bordered by the second
polymer.
9: The sheet product of claim 8, wherein segments of the first
polymer are present in the sheet product in a circular, oval, or
n-angular, trilobal, or multilobal cross section, and wherein
segments of the first polymer are embedded in the second polymer
and/or at least partly bordered by the second polymer.
10: The sheet product of claim 8, wherein the fibers have a
sheath-core geometry.
11: The sheet product of claim 1, wherein a weight ratio of the
first to the second polymer is in a range of from 50:50 to
95:5.
12: The sheet product of claim 1, wherein the ply is a non-crimp
fabric, a woven fabric, a knit fabric, a film, a foil, a batt or a
nonwoven.
13: The sheet product of claim 1, wherein the main body includes a
composite material comprising the ply.
14: The sheet product of claim 1, having a basis weight as measured
to DIN EN 29073 1 in a range of from 50 to 4000 g/m.sup.2.
15: The sheet product of claim 1, which is a thermoformed sheet
product.
16: A bicomponent fiber, comprising: a first polymer; and a second
polymer, wherein a cold crystallization temperature of the first
polymer is equal to the softening temperature of the second polymer
or below the softening temperature of the second polymer.
17: A method for manufacturing a component part of a transport
apparatus, the method comprising: a sheet product as claimed in any
preceding claim in the manufacture of a component part for a means
of transport.
18: The sheet product of claim 1, wherein a difference between the
softening temperatures of the first and second polymers as measured
to DIN 53765 is at least 20.degree. C.
19: The sheet product of claim 1, wherein a difference between the
softening temperatures of the first and second polymers as measured
to DIN 53765 is at least 25.degree. C.
20: The sheet product of claim 2, wherein a difference between the
melting temperatures of the first and second polymers is at least
10.degree. C.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. national stage application under
35 U.S.C. .sctn.371 of International Application No.
PCT/EP2014/002469, filed on Sep. 12, 2014, and claims benefit to
German Patent Application No. DE 10 2013 016 293.9, filed on Oct.
2, 2013. The International application was published in German on
Apr. 9, 2015, as WO 2015/049027 A1 under PCT Article 21(2).
FIELD
[0002] The invention relates to a sheet product, preferably of high
thermal stability, and also to its use in the manufacture of a
component part for a means of transport.
BACKGROUND
[0003] Sheet products of the type referred to at the beginning are
already known from the prior art and are used in many fields, for
example in the transportation industry. Sheet products of this type
typically contain a very wide variety of materials, for example
glass fibers, polyurethanes or polyesters.
[0004] U.S. Pat. No. 3,966,526 describes a method of making
component parts for automotive interior trim. They are constructed
of multiple foam-type layers comprising polystyrene resin. The
disadvantage here is that these component parts are not recyclable
and their disposal is accordingly associated with high costs.
[0005] A further component part for the automotive industry, namely
a headliner, is shown in U.S. Pat. No. 4,840,832. The headliner
comprises bicomponent fibers of polyester having a low-melting
binder component and a high-melting stabilizing polymer.
[0006] U.S. Pat. No. 5,275,865 discloses a further headliner for
automotive interior trim, this headliner containing partially
oriented polyester fibers and no binder.
[0007] U.S. Pat. No. 4,119,749 describes a lightweight headliner
for automotive interior trim. It has a multilayered construction. A
layer of polyurethane foam is employed as core element in that one
side of the polyurethane foam layer is provided a further
polyurethane foam layer. The other side is impregnated with an
elastomer solution. The individual layers need to be separated to
dispose of the headliner. This increases the costs of disposal.
Recycling of the foams is also not possible owing to the selected
materials.
[0008] U.S. Pat. No. 4,211,590 shows a thermoformable laminate
comprising a thermoplastic foam-type core. After thermoforming, the
laminate is rigidified by cooling. A laminate of this type is used
for trimming the interior of an automobile, particularly as a
headliner.
[0009] A further headliner for automotive interior trim is known
from U.S. Pat. No. 5,660,908. It consists of polyethylene
terephthalate and has reinforcing ribs. The disadvantage here is
its lack of thermal stability. Adequate thermal stability is
achievable through a complicated construction. This requires a
costly and inconvenient method of making.
[0010] Sheet products of the type referred to at the beginning
typically have a low level of flexural stiffness at elevated
temperature, are not recyclable or have a high level of stiffness
coupled with low elasticity/formability. This compromises the
processing of such a sheet product; especially the processing of
such a sheet product into interior trim for an automobile, is
associated with appreciable difficulties. The achievement of
adequate stability while retaining the elasticity of the sheet
product requires a multilayered structural design. This in turn
requires a costly and inconvenient method of making.
SUMMARY
[0011] An aspect of the invention provides a sheet product,
comprising: a main body comprising a ply, wherein the ply comprises
first fibers comprising a first polymer and second fibers
comprising a second polymer or wherein the ply comprises unitary
fibers comprising first and second polymers, wherein a cold
crystallization temperature of the first polymer is equal to the
softening temperature of the second polymer or below the softening
temperature of the second polymer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention will be described in even greater
detail below based on the exemplary figures. The invention is not
limited to the exemplary embodiments. All features described and/or
illustrated herein can be used alone or combined in different
combinations in embodiments of the invention. The features and
advantages of various embodiments of the present invention will
become apparent by reading the following detailed description with
reference to the attached drawings which illustrate the
following:
[0013] FIG. 1 shows a sheet product comprising a main body of one
ply, said ply containing fibers from two polymers;
[0014] FIG. 2 shows a schematic arrangement of a thermoformable
sheet product;
[0015] FIG. 3 shows a further schematic arrangement of a
thermoformable sheet product;
[0016] FIG. 4 shows a schematic arrangement of a two-ply
thermoformable sheet product;
[0017] FIG. 5 shows a diagram comparing the heating curve of the
first polymer with the second polymer;
[0018] FIG. 6a shows a trilobal fiber in cross section;
[0019] FIG. 6b shows a further trilobal fiber in cross section;
and
[0020] FIGS. 7a-c show optical micrographs of cross sections
through three bicomponent fibers.
DETAILED DESCRIPTION
[0021] An aspect of the invention therefore addresses the problem
of refining and developing a sheet product of the type referred to
at the beginning such that it, following inexpensive fabrication,
has a high level of flexural stiffness at elevated temperature, and
is recyclable, mechanically strong and elastically resilient. This
sheet product shall find use in particular as a component part for
a means of transport.
[0022] In an aspect, the sheet product referred to at the beginning
accordingly comprises a main body of at least one ply, wherein the
at least one ply contains first fibers comprising a first polymer
and second fibers comprising a second polymer or wherein the at
least one ply comprises unitary fibers containing first and second
polymers, wherein a cold crystallization temperature of the first
polymer is equal to the softening temperature of the second polymer
or below the softening temperature of the second polymer.
[0023] Cold crystallization is to be understood as meaning a
crystallization occurring after heating beyond the softening and/or
glass transition temperature.
[0024] Cold crystallization temperature is to be understood as
meaning the temperature at which a first exothermic maximum of the
free enthalpy occurs. Exothermic is to be understood as meaning a
release of energy.
[0025] Softening temperature, also known as glass transition
temperature, is to be understood as meaning the temperature at
which wholly or partly amorphous polymers transition from a highly
viscous or rubberily elastic, flexible state into a glass-type or
hard elastic state. Softening temperature in this invention is
measured to DIN 53765.
[0026] By unitary fibers is meant that the fibers have the same
polymers and the same fiber type.
[0027] The inventors recognized that the cold crystallization of
the first polymer causes a stabilization of the second polymer to
occur at the softening temperature of the second polymer or below
the softening temperature of the second polymer. This results in a
sheet product having sufficiently high mechanical strength at high
temperatures. The sheet product is further notable for outstanding
acoustical properties and a low weight.
[0028] The problem referred to at the beginning has accordingly
been solved.
[0029] Preferably, a cold crystallization of the first polymer
occurs at a softening temperature of the second polymer in the
range from 70 to 150.degree. C., preferably in the range from 80 to
140.degree. C., more preferably in the range from 90 to 130.degree.
C. These conditions result in a sheet product having high
flexibility and elastic yieldingness at high temperatures.
[0030] At these temperatures, a stabilization of the second polymer
takes place due to crystallization of the first polymer.
[0031] Preferably, there is no difference between the cold
crystallization temperature of the first polymer and the softening
temperature of the second polymer. However, the difference between
the cold crystallization temperature of the first polymer and the
softening temperature of the second polymer could also be in the
range from 1 to 100.degree. C., preferably in the range from 2 to
80.degree. C., more preferably in the range from 3 to 60.degree. C.
These conditions result in particularly good stabilization of the
second polymer due to cold crystallization of the first
polymer.
[0032] In one preferred embodiment, the softening temperature
and/or the melting temperature of the second polymer are/is above
the softening temperature and/or the melting temperature of the
first polymer. Specific selection of the polymers with regard to
their softening temperatures and also their melting temperatures
ensures particularly good stabilization of the first polymer due to
the second polymer up to the softening temperature of the second
polymer. The specific selection of the polymers and their
arrangement due to the cold crystallization of the first polymer
further endow the sheet product with a level of thermal stability
that is distinctly above the softening temperature and the melting
temperature of either polymer.
[0033] The difference between the softening temperatures as
measured to DIN 53765 for the first and second polymers can vary
within wide limits. Advantageously, the difference in the softening
temperatures of the first and second polymers is at least
15.degree. C., preferably at least 20.degree. C., more preferably
at least 25.degree. C. Preference is given to employing polymers
having a temperature difference of from 15 to 450.degree. C., more
preferably from 20 to 150.degree. C., yet more preferably from 25
to 100.degree. C. Practical tests have shown that these values
provide a particularly high level of thermal stability to the sheet
product.
[0034] In one preferred embodiment, the difference between the
melting temperatures of the first and second polymers is at least
5.degree. C., preferably at least 10.degree. C., more preferably at
least 15.degree. C. Preference is given to using polymers having a
temperature difference of from 5 to 200.degree. C., more preferably
of from 10 to 150.degree. C., yet more preferably from 15 to
120.degree. C. This difference in the melting temperatures of the
two polymers leads to good thermal stability and to good
load-deflection characteristics for the sheet product.
[0035] A very wide variety of materials are employable as polymers.
Preferably, the polymers are melt spinnable. Preferably, at least
one of the polymers is a polyester selected from the group
consisting of polyethylene terephthalate, polypropylene
terephthalate, polytetramethylene terephthalate,
poly(decamethylene) terephthalate, poly-1,4-cyclo-hexylene dimethyl
terephthalate, polybutylene terephthalate, polyethylene
naphthalate, polyglycolic acid, polylactides, polycaprolactones,
polyethylene adipates, polyhydroxyalkanoates, polyhydroxybutyrates,
poly-3-hydroxybutyrate-co-3-hydroxyvalerates, poly-trimethylene
terephthalates, vectrans, polyethylene naphthalate, their
copolymers and/or their mixtures. Sheet products comprising the
aforementioned polymers are readily recyclable.
[0036] It is extremely preferable for the first polymer to be
selected from the group consisting of polypropylene terephthalate,
polytetramethylene terephthalate, poly(decamethylene)
terephthalate, poly-1,4-cyclo-hexylene dimethyl terephthalate,
polybutylene terephthalate, polyethylene terephthalate, more
preferably polypropylene terephthalate, polytetra-methylene
terephthalate, polyethylene terephthalate, their copolymers and/or
their mixtures.
[0037] It is further extremely preferable for the second polymer to
be selected from the group consisting of
poly(decamethylene)terephthalate, poly-1,4-cyclo-hexylene dimethyl
terephthalate, polybutylene terephthalate, polyethylene
naphthalate, more preferably polyethylene naphthalate, polybutylene
terephthalate, their copolymers and/or their mixtures. A suitable
choice of the polymers used can be used to influence the thermal
stability and also the mechanical properties, in particular the
elasticity, formability and strength of the sheet product. This
enables custom-tailoring of the sheet product to various
applications, preferably to applications of the sheet product as a
substrate for interior trimming of means of transport and as a
cladding material for the outside.
[0038] It is very particularly preferable for the first polymer to
be a polyester selected from the group consisting of polyglycolic
acid, polylactides, polycaprolactones, polyethylene adipates,
polyhydroxy-alkanoates, polyhydroxybutyrates,
poly-3-hydroxy-butyrate-co-3-hydroxyvalerates, polyethylene
terephthalate, polypropylene terephthalate, poly-butylene
terephthalate, polytrimethylene terephthalates, vectrans,
polytetramethylene terephthalate, poly(decamethylene)
terephthalate, poly-1,4-cyclohexylene dimethyl terephthalate,
polyethylene naphthalate, their copolymers and/or their mixtures
and for the second polymer to contain polyethylene naphthalate.
[0039] In a preferred embodiment, the first polymer contains
polyethylene terephthalate and/or co-polyethylene terephthalate and
the second polymer contains polyethylene naphthalate.
[0040] Preferably, the first polymer has a cold crystallization
temperature in the range from 70 to 150.degree. C., more preferably
in the range from 80 to 140.degree. C., most preferably in the
range from 90 to 130.degree. C. These polymers have a high level of
thermal stability and lead to good load-deflection characteristics
for the sheet product.
[0041] In a further preferred embodiment, the second polymer has a
softening temperature in the range from 70 to 150.degree. C., more
preferably in the range from 80 to 140.degree. C., most preferably
in the range from 90 to 130.degree. C. This results in particularly
good stabilization of the second polymer through cold
crystallization of the first polymer.
[0042] Practical tests have shown that particularly high
stiffnesses are achieved when the first polymer has a lower modulus
of elasticity than the second polymer. The modulus of elasticity is
a physical parameter from the science of engineering materials, and
describes the relationship between stress and strain as a solid
body undergoes deformation in the linear elastic region. The first
polymer could have a modulus of elasticity in the range from 400 to
1300 MPa, preferably in the range from 500 to 1200 MPa, more
preferably in the range from 700 to 1000 MPa.
[0043] The second polymer could have a high modulus of elasticity.
The second polymer preferably has a modulus of elasticity in the
range from 1400 to 3000 MPa, more preferably in the range from 1600
to 2500 MPa, yet more preferably in the range from 2000 to 2200
MPa. This provides an outstanding level of flexural stiffness at
elevated temperature.
[0044] Preferably, at least one fiber contains at least two
polymers, wherein the first polymer is in the form of at least one
segment embedded in the second polymer and/or at least partly
bordered by the second polymer. This causes the second polymer to
stabilize the first polymer under high temperatures until the first
polymer undergoes cold crystallization.
[0045] Advantageously, segments of a first polymer are present in
the sheet product in a circular, oval or n-angular, trilobal or
multilobal cross section and embedded in the second polymer and/or
at least partly bordered by the second polymer. The alternating
arrangement of the individual segments results in an optimal and
uniform arrangement of the first polymer in the form of segments
embedded in the second polymer and/or at least partly bordered by
the second polymer. Round segments are preferable and their coaxial
arrangement is particularly preferable. Force absorption is good as
a result of this isotropic arrangement.
[0046] The fibers could have a sheath-core geometry. In a
sheath-core geometry, the first polymer in the core of a
filamentary strand is surrounded by the second polymer. Preferably,
the core contains polypropylene terephthalate, polytetramethylene
terephthalate, poly(decamethylene) terephthalate,
poly-1,4-cyclo-hexylene dimethyl terephthalate, polybutylene
terephthalate, polyethylene terephthalate, more preferably
polypropylene terephthalate, polytetra-methylene terephthalate,
polyethylene terephthalate, their copolymers and/or their mixtures
and the sheath contains with preference poly(decamethylene)
terephthalate, poly-1,4-cyclohexylene dimethyl terephthalate,
polybutylene terephthalate, polyethylene naphthalate, more
preferably polyethylene naphthalate, polybutylene terephthalate,
their copolymers and/or their mixtures. In these geometries, the
first polymer is advantageously embedded in the second polymer in a
particularly homogeneous manner, and these geometries lead to a
particularly dense structure.
[0047] The fibers are advantageously embodied as monofibers. It is
advantageous in this connection for the second polymer to be
adhered to the first polymer and for the first polymer to act as a
binder fiber and create an adhesive bond between the fibers of the
first and second polymers. This serves to enhance the mechanical
strength of the sheet product.
[0048] In a further preferred embodiment, the fibers have a
sheath-core geometry where the fibers contain just one polymer.
There is preferably no polymer in the core. Hollow fibers are
concerned in this case. This is advantageous in providing a sheet
product of low weight and high mechanical strength.
[0049] It is further preferable for the polymer of the hollow fiber
to be a polyester selected from the group consisting of
polypropylene terephthalate, polytetramethylene terephthalate,
poly(decamethylene) terephthalate, poly-1,4-cyclohexylene dimethyl
terephthalate, polybutylene terephthalate, polyethylene
terephthalate, polypropylene terephthalate, polytetramethylene
terephthalate, polyethylene terephthalate, polyethylene
naphthalate, their copolymers and/or their mixtures. It is
extremely preferable for the polymer of the hollow fiber to contain
polyethylene naphthalate.
[0050] It is extremely preferable for the polymer of the hollow
fiber to have a softening temperature in the range from 70 to
150.degree. C., more preferably in the range from 80 to 140.degree.
C., extremely preferably in the range from 90 to 130.degree. C.
This provides a particularly stable sheet product of low
weight.
[0051] In a preferred embodiment, the weight ratio of the first to
the second polymer is in a range from 50:50 to 95:5, preferably in
a range from 60:40 to 95:5, more preferably in a range from 65:35
to 90:10. Advantageously, even a small fraction of the polymer
having the higher softening and/or melting temperature is
sufficient to obtain optimal stabilization of the polymer having
the lower softening and/or melting temperature. It is further
possible to reduce manufacturing costs by having a low proportion
of the second polymer, since it is typically the costlier
component.
[0052] Fiber diameter is preferably in the range from 0.1 to 20
dtex, more preferably in the range from 1 to 15 dtex, yet more
preferably in the range from 3 to 12 dtex. It is particularly
preferred to employ the second polymer as the minority component.
The advantage with this is that the typically costly second
polymeric component can be employed in a material-saving manner to
enhance the stability of the sheet product.
[0053] The stability of the sheet product can further be
additionally enhanced by using a first polymer to partly or wholly
fill the voids between the fibers.
[0054] In a preferred embodiment, the main body does not contain
any further fibers. Conceivably, the main body could include
further fibers. These fibers are preferably embodied as monofibers.
The proportion of further fibers in relation to the overall weight
of the main body is preferably in the range from 1 to 80 wt %,
preferably from 10 to 70 wt %, more preferably from 20 to 60 wt
%.
[0055] In a preferred embodiment, the further fibers contain a
polymer selected from the group consisting of polyesters,
polyolefins, polyamide, nylon 66 (Nylon.RTM.), nylon 6 (Perlon.RTM.
preferably polyethylene terephthalate, polypropylene terephthalate,
their copolymers and/or their mixtures.
[0056] The fibers may be embodied as binder fibers. The binder
fiber creates an adhesive bond serving to enhance the strength of
the sheet product.
[0057] The plies, preferably the at least one ply and/or the
further plies of the main body, could be embodied as a non-crimp
fabric, as a woven fabric, as a knit fabric, as a film, as a foil,
as a batt or as a nonwoven. A sheet product having mechanical
strength is obtained as a result.
[0058] The main body could include a composite material which
contains the at least one ply. The mechanical strength of the sheet
product is enhanced as a result.
[0059] It is conceivable for the sheet product to include a
reinforcing ply. Preferably, the sheet product does not include any
reinforcing ply. This provides a sheet product of high mechanical
strength and low weight.
[0060] Against this background it is also conceivable to subject
the sheet product to a chemical type of finish or treatment, for
example--if needed or desired--a hydrophilicization, an antistatic
treatment, a treatment to improve the fire resistance or the light
stability and/or to modify the tactile properties or the luster,
and/or a treatment to modify the appearance such as dyeing or
printing.
[0061] Basis weight may vary between wide limits. The sheet product
preferably has a basis weight as measured to DIN EN 29073 1 in the
range from 50 to 4000 g/m.sup.2, preferably in the range from 80 to
3000 g/m.sup.2, more preferably in the range from 100 to 2500
g/m.sup.2. Sheet products having the aforementioned basis weights
possess outstanding stability.
[0062] In a preferred embodiment, the sheet product is used as a
headliner substrate. In this use, the sheet product preferably has
a basis weight in the range from 500 to 2500 g/m.sup.2, more
preferably in the range from 100 to 1000 g/m.sup.2, extremely
preferably in the range from 200 to 800 g/m.sup.2.
[0063] In a preferred embodiment, the sheet product has a DIN EN
9073 2 thickness of from 0.5 to 300 mm, more preferably from 1 to
200 mm, yet more preferably from 1 to 150 mm. Sheet products of
this type have particularly good processing properties by virtue of
their low thickness and good formability.
[0064] The present invention further provides a bicomponent fiber
containing first and second polymers, wherein a cold
crystallization temperature of the first polymer is equal to the
softening temperature of the second polymer or below the softening
temperature of the second polymer.
[0065] In a preferred embodiment, the sheet product is subjected to
a thermoforming operation to obtain a thermoformed sheet product.
Thermoforming is a forming operation practiced on thermoplastic
materials. The thermoformed sheet product could be obtainable by a
process comprising the steps of:
[0066] a) heating the sheet product,
[0067] b) introducing the sheet product into a mold,
[0068] c) compression molding in the mold, and
[0069] d) removing the sheet product from the mold.
[0070] The mold could be heated to a temperature in the range from
20 to 300.degree. C., preferably in the range from 20 to
250.degree. C. The mold advantageously has two halves. The two
halves of the mold may be spaced apart the same or differently at
various points of the compression-molding surface during the
compression-molding step. Practical tests have shown that under
these conditions the thermoformable sheet product is endowed with
an enhanced level of flexural stiffness at elevated
temperature.
[0071] The flexural stiffness of the sheet product may vary between
wide limits. The sheet product is preferably used in the
manufacture of a component part for a means of transport, in
particular as a substrate for a headliner. Sheet products of this
type preferably have a flexural stiffness in the range from 1 to 40
N/mm.sup.2 as measured to DIN EN ISO 14125 at a maximal flexural
stress, more preferably in the range from 1 to 25 N/mm.sup.2, yet
more preferably in the range from 2 to 20 N/mm.sup.2, extremely
preferably in the range from 4 to 15 N/mm.sup.2. Sheet products
having the aforementioned flexural stiffnesses combine outstanding
formability with sufficient stability.
[0072] The flexural stiffness of the thermoformed sheet product can
also be determined according to DIN/EN 310. On setting the test
speed to 20 mm/min, the sample size to 90 mm.times.75 mm, the
support point separation to 80 mm and the initial force to 3 N, it
is possible to obtain flexural stiffnesses in the range from 1 to
40 N, preferably from 5 to 35 N and particularly from 10 to 30 N.
The thermoformed sheet product embodied as substrate for a
headliner could further have a modulus of elasticity (E-modulus) in
the range from 20 to 350 MPa as measured to EN ISO 14125 at a
maximal flexural stress, preferably in the range from 30 to 280
MPa, more preferably in the range from 40 to 250 MPa. The modulus
of elasticity is a physical parameter from the science of
engineering materials, and describes the relationship between
stress and strain as a solid body undergoes deformation in the
linear elastic region.
[0073] The modulus of elasticity of the thermoformed sheet product
can also be determined according to DIN EN ISO 178. On setting the
test speed to 20 mm/min, the sample size to 90 mm.times.75 mm, the
support point separation to 80 mm and the initial force to 3 N, it
is possible to obtain moduli of elasticity in the range 20 to 600
MPa, preferably from 30 to 500 MPa and particularly from 40 to 450
MPa.
[0074] In a further preferred embodiment, the sheet product
embodied as substrate for a headliner has a modulus of elasticity
(E-modulus) in the range from 10 to 350 MPa as measured to EN ISO
14125 or to DIN EN ISO 178 at a maximal flexural stress and a
temperature of 120.degree. C., preferably in the range from 15 to
250 MPa, more preferably in the range from 20 to 200 MPa. It is
advantageous here that the sheet product possesses an enhanced
level of mechanical strength at high temperatures. Aging processes
preferentially proceed very slowly, so the sheet product stands up
even to the high requirements which component parts are expected to
meet in the automotive industry. A surface, for example, must not
exhibit any color change or scarring after several months of
photoaging at 120.degree. C.
[0075] In a preferred embodiment, the sheet product has a multi-ply
construction. Preferably, the sheet product contains further plies
in addition to the main body. The further plies could be embodied
as spunbond plies or as a staple fiber ply. The further plies
differ from each other in their function, method of making, fiber
type, containing polymers and/or in their color. A combination of
staple fiber ply and spunbond ply leads to a voluminous sheet
product for the same basis weight. The sheet product could further
have further plies embodied as spunbond or staple fiber ply. This
improves the acoustical properties.
[0076] In a further preferred embodiment, the thermoformed sheet
product comprises a sandwich structure wherein the outer plies
contain the sheet product of the present invention. The central ply
could comprise a staple fiber ply or a further spunbond ply.
Advantageously, the sandwich-type construction enhances the
flexural stiffness and endows the sheet product with excellent
strength. The following further sequences are considerable.
Hereinbelow SF represents a staple fiber ply and SL represents a
spunbond ply: SF/SL/SF; SF/SL; SL/SF.
[0077] These sequences could also be combined with plies as
described above.
[0078] The sheet product of the present invention has high flexural
stiffness at elevated temperature, a low weight and sound
absorption and therefore is useful in the manufacture of a
component part for a means of transport. The sheet product is very
useful as a substrate for the interior fitment of a means of
transport, more preferably as a substrate for a headliner, as a
substrate for an internal door trim panel, as a substrate for a
parcel shelf and/or as a substrate in the exterior region of a
means of transport, more preferably as a substrate for an underbody
and as a substrate for a wheel box. Means of transport is to be
understood as referring to automobiles, trucks, coaches, rail cars,
airplanes, ships, recreational vehicles, agricultural machines
and/or campers.
[0079] In one preferred embodiment, the sheet product is used as a
substrate for interior trim paneling of a coach, of a camper, of a
recreational vehicle, of a ship, of an airplane or of a rail
vehicle. The sheet product is suitable for the aforementioned uses
by virtue of its mechanical strength and its low weight.
[0080] It is further conceivable to use the sheet product as a
substrate for an interior fitting-out of ships' cabins and/or
airplane cabins because of its low weight.
[0081] The sheet product could further be used in the manufacture
of a component part for a building, preferably as a substrate for
mobile dividing walls or partitions in buildings. This use rests on
the low weight of the sheet product and its outstanding acoustical
properties.
[0082] The invention will now be more particularly described with
reference to a number of examples which do not limit the
invention.
Example 1
Making an Inventive Sheet Product
[0083] PEN pellet (Advanite 71001 from SASA) and copolyester pellet
(CS 123 N from FENC) material is dried and subsequently melt spun
into a mixture of monofibers and bicomponent fibers.
[0084] The processing temperature is 300.degree. C. for Advanite
and 270.degree. C. for CS 123 N.
[0085] The spinneret die used is a 195 hole die having a
bicomponent fiber fraction of 60%. The PEN is exclusively imported
into the sheath of the bicomponent fiber, the copolyester not only
into the core of the bicomponent fiber but also into the
monofiber.
[0086] Three different ratios of PEN/copolyester are created in the
bicomponent fiber.
[0087] 1. 30% PEN (sheath) 70% copolyester (core)
[0088] 2. 25% PEN (sheath) 85% copolyester (core)
[0089] 3. 20% PEN (sheath) 80% copolyester (core)
[0090] Optical micrographs of cross sections through the above
bicomponent fibers 1-3 are shown in FIGS. 7a-c.
Example 2
Determining Relevant Fiber Parameters
[0091] Some relevant fiber properties are determined on the spun
bicomponent fibers as follows:
[0092] fineness: 8.5 dtex
[0093] tenacity: 21.54 cN/tex
[0094] elongation: 10.19%
[0095] boil shrinkage: 3.25%
[0096] In addition, thermal stability under temperature forcing was
tested as follows:
[0097] A bicomponent fiber 8 cm in length was stretched between two
metal blocks 4 cm apart and loaded with a weight of 1 g in the
center. The fiber was taut.
[0098] The temperature was then raised to 100.degree. C., which is
above the Tg of the copolyester used and below the Tg of the PEN.
No sagging was observed for the bicomponent fiber. Next the
temperature was raised to 125.degree. C., this temperature being
within the softening range of the PEN. Again no sagging was
observed. Finally, the temperature was raised to 140.degree. C.
This temperature is above the softening range of the polyester.
Merely minimal sagging was observed at this temperature.
[0099] Since the copolyester already softens in a range of 55
65.degree. C., a standard polyester monofiber (PET) was used as
reference. The test performed has shown that distinct sagging of
the PET monofiber is observed on reaching just 100.degree. C.
Example 3
Production of Multi-Ply Hybrid Materials
[0100] The spunbond made in Example 1 was combined with a staple
fiber ply as a reinforcing ply consisting of bicomponent fibers
(LMF50 from Huvis, PET/CoPET, 4.4 dtex, 64 mm) to produce not only
two-ply but also three-ply hybrid materials.
[0101] To this end, either one or two spunbonds were combined with
one staple fiber ply by means of a needle loom. In the three-ply
hybrid materials, the staple fiber batt was in each case placed in
the center.
[0102] Six different hybrid materials were made using the following
settings for the needle loom:
TABLE-US-00001 frequency 1000 min.sup.-1 penetration 10 mm speed 4
m needle board 15 .times. 18 .times. 40 .times. 3.5 (Singer)
[0103] Hybrid Materials Obtained
TABLE-US-00002 number of plies basis weight 2 410 g/m.sup.2 2 480
g/m.sup.2 2 530 g/m.sup.2 2 640 g/m.sup.2 3 470 g/m.sup.2 3 510
g/m.sup.2
[0104] Following needling, the hybrid materials were consolidated
using a belt dryer. Belt dryer setting:
TABLE-US-00003 speed 1 m temp. of chamber 1 230.degree. C. temp. of
chamber 2 230.degree. C. 1 air recycled 100% 2 air recycled 100% 1
nozzle adjustment 1.5 cm 2 nozzle adjustment 1.5 cm air exhausted
80%
[0105] Consolidated Hybrid Materials Obtained
TABLE-US-00004 number of basis mass mass plies weight increase/g
increase/% 2 440 g/m.sup.2 30 7.3 2 520 g/m.sup.2 40 8.3 2 580
g/m.sup.2 50 9.4 2 700 g/m.sup.2 60 8.6 3 510 g/m.sup.2 40 8.5 3
560 g/m.sup.2 50 9.8
[0106] Test specimens 90 mm.times.75 mm in size were die-cut out of
the hybrid materials obtained and compression molded at a
temperature of 180.degree. C. down to a thickness of 2.1 2.5 mm,
followed by the determination of the bending force to DIN/EN 310 at
an initial force of 3 N and a test speed of 20 mm, the E-modulus to
DIN EN ISO 178 at the same initial force and test speed.
TABLE-US-00005 basis E-modulus/ bending path/ weight MPa force/N mm
440 g/m.sup.2 105 4.7 4.4 520 g/m.sup.2 136 6.4 8.1 580 g/m.sup.2
171 7.9 10.2 700 g/m.sup.2 232 16.3 12.5 510 g/m.sup.2 151 6.5 8.3
560 g/m.sup.2 142 7.7 9.6
[0107] FIG. 1 shows a sheet product 1 comprising a main body of one
ply 2, said ply 2 containing fibers from two polymers.
[0108] Ply 2 has a single-ply construction.
[0109] FIG. 2 shows a schematic arrangement of a thermo-formable
sheet product 1'. The sheet product 1' has a multi-ply construction
in that it contains further plies besides ply 2. Ply 2 is embodied
as a spunbond ply. The sheet body 1' includes a ply 3 of staple
fibers as the bottommost layer. A ply 2 is arranged atop this ply
3. A further ply 3 of staple fibers is positioned atop ply 2.
[0110] FIG. 3 shows a further schematic arrangement of a
thermoformable sheet product 1''. The sheet product 1'' has a
multi-ply construction in that it contains further plies besides
ply 2. The sheet product 1'' includes ply 2 as the bottommost
layer. A ply 3 of staple fibers is arranged atop this ply 2. A
further ply 2 is positioned atop ply 3 of staple fibers.
[0111] FIG. 4 shows yet a further schematic arrangement of a
thermoformable two-ply sheet product 1'''. The sheet product 1'''
includes ply 2 as bottommost layer. A staple fiber ply 3 is
arranged atop this ply 2.
[0112] FIG. 5 shows a diagram comparing the heating curve of the
first polymer with the second polymer according to the
temperature.
[0113] The upper curve 4 shows the heating behavior of the first
polymer and the lower curve 5 describes the heating behavior of the
second polymer. The softening temperature 6 of the first polymer is
below the softening temperature 7 of the second polymer.
[0114] The cold crystallization temperature 8 of the first polymer
is below the softening temperature 7 of the second polymer. The
cold crystallization temperature 9 of the second polymer is above
the cold crystallization temperature 8 of the first polymer.
[0115] FIG. 6a shows a cross section through a trilobal fiber
containing two polymers, the first polymer 10 being in the form of
at least one segment embedded in a second polymer 11.
[0116] FIG. 6b shows a cross section through a trilobal fiber
containing two polymers, the first polymer 10 being in the form of
at least one segment at least partly bordered by the second polymer
11.
[0117] While the invention has been illustrated and described in
detail in the drawings and foregoing description, such illustration
and description are to be considered illustrative or exemplary and
not restrictive. It will be understood that changes and
modifications may be made by those of ordinary skill within the
scope of the following claims. In particular, the present invention
covers further embodiments with any combination of features from
different embodiments described above and below. Additionally,
statements made herein characterizing the invention refer to an
embodiment of the invention and not necessarily all
embodiments.
[0118] The terms used in the claims should be construed to have the
broadest reasonable interpretation consistent with the foregoing
description. For example, the use of the article "a" or "the" in
introducing an element should not be interpreted as being exclusive
of a plurality of elements. Likewise, the recitation of "or" should
be interpreted as being inclusive, such that the recitation of "A
or B" is not exclusive of "A and B," unless it is clear from the
context or the foregoing description that only one of A and B is
intended. Further, the recitation of "at least one of A, B, and C"
should be interpreted as one or more of a group of elements
consisting of A, B, and C, and should not be interpreted as
requiring at least one of each of the listed elements A, B, and C,
regardless of whether A, B, and C are related as categories or
otherwise. Moreover, the recitation of "A, B, and/or C" or "at
least one of A, B, or C" should be interpreted as including any
singular entity from the listed elements, e.g., A, any subset from
the listed elements, e.g., A and B, or the entire list of elements
A, B, and C.
* * * * *