U.S. patent application number 14/383368 was filed with the patent office on 2015-02-12 for planar composite material.
The applicant listed for this patent is QUADRANT PLASTIC COMPOSITES AG. Invention is credited to Burak Baser.
Application Number | 20150044438 14/383368 |
Document ID | / |
Family ID | 47997379 |
Filed Date | 2015-02-12 |
United States Patent
Application |
20150044438 |
Kind Code |
A1 |
Baser; Burak |
February 12, 2015 |
PLANAR COMPOSITE MATERIAL
Abstract
A planar composite material comprises an UD fiber layer A made
of discrete reinforcing fiber rovings and a fiber nonwoven layer B
made of a thermoplastic nonwoven which may contain reinforcing
fibers, wherein the layers A and B are needled to each other.
Inventors: |
Baser; Burak; (Aarburg,
CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUADRANT PLASTIC COMPOSITES AG |
Lenzburg |
|
CH |
|
|
Family ID: |
47997379 |
Appl. No.: |
14/383368 |
Filed: |
March 11, 2013 |
PCT Filed: |
March 11, 2013 |
PCT NO: |
PCT/EP2013/054844 |
371 Date: |
September 5, 2014 |
Current U.S.
Class: |
428/212 ;
156/243; 28/108 |
Current CPC
Class: |
B32B 2605/08 20130101;
B32B 2250/20 20130101; B32B 2262/101 20130101; B32B 2307/718
20130101; B32B 2605/10 20130101; D04H 3/04 20130101; D04H 13/005
20130101; B32B 5/022 20130101; B32B 2262/0253 20130101; D04H 3/03
20130101; B32B 2250/04 20130101; B32B 2250/40 20130101; D04H 5/02
20130101; B32B 2262/108 20130101; B32B 2262/0261 20130101; B32B
1/00 20130101; D04H 1/485 20130101; Y10T 428/24942 20150115; B32B
2250/03 20130101; B32B 2250/42 20130101; D04H 1/498 20130101; B32B
2262/0269 20130101; D04H 3/105 20130101; B32B 2307/706 20130101;
D04H 1/732 20130101; B32B 5/08 20130101; B32B 5/26 20130101; B32B
37/04 20130101; B32B 2605/18 20130101; B32B 2305/20 20130101; B32B
2250/02 20130101; D04H 1/74 20130101; B32B 2262/106 20130101; B29C
70/506 20130101; D04H 1/72 20130101; B32B 2307/738 20130101; D04H
5/03 20130101; B29C 70/083 20130101; B32B 5/06 20130101 |
Class at
Publication: |
428/212 ; 28/108;
156/243 |
International
Class: |
B32B 5/26 20060101
B32B005/26; B32B 5/02 20060101 B32B005/02; B32B 5/06 20060101
B32B005/06; B32B 37/04 20060101 B32B037/04; D04H 3/04 20060101
D04H003/04; D04H 13/00 20060101 D04H013/00; D04H 1/485 20060101
D04H001/485; B32B 5/08 20060101 B32B005/08; D04H 3/03 20060101
D04H003/03 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 9, 2012 |
EP |
12158958.4 |
Claims
1.-15. (canceled)
16. A planar composite material comprising: a) at least one UD
fiber layer A of discrete, unidirectional reinforcing fiber rovings
(6) which are not connected to each other, having an areal weight
of more than 300 and up to 2,000 g/m.sup.2 and b) at least one
fiber mat with randomly oriented fibers B having an areal weight of
100 to 2,000 g/m.sup.2 comprising a thermoplastic fiber nonwoven or
a thermoplastic oriented fiber layer, each of which optionally
contains up to 70 wt.-% reinforcing fibers wherein the layers A and
B are needled to each other.
17. The composite material of claim 16, having a layer sequence
A-B.
18. The composite material of claim 16, the fiber mat with randomly
oriented fibers B comprises a thermoplastic fiber nonwoven which is
a needled nonwoven or a non-needled carding or airlay nonwoven
which is formed of thermoplastic fibers and optionally contains 30
to 70 wt.-% reinforcing fibers.
19. The composite material of claim 18, further comprising, on the
side of the layer B which is facing away from the layer A, a fiber
layer C comprising nondirectional reinforcing fibers having an
areal weight of 50 to 500 g/m.sup.2.
20. The composite material of claim 16, wherein the fiber mat with
randomly oriented fibers B comprises a thermoplastic oriented fiber
layer of continuous thermoplastic fibers, which optionally
continuous reinforcing fibers.
21. The composite material of claim 16, comprising 30 to 80 wt.-%
UD fibers based on the total weight of the composite material.
22. The composite material of claim 16, wherein the reinforcing
fiber rovings of layer A are glass, carbon, aramide or basalt
fibers with a titer of 200 to 4,800 tex.
23. The composite material of claim 16, wherein the thermoplastic
of layer B is unmodified polypropylene, polyamide-6, or
polyamide-6,6.
24. The composite material of claim 18, wherein the UD fibers of
layer A are carbon fibers and the fiber nonwoven layer B contains
30 to 70 wt.-% recycled carbon fibers and 70 to 30 wt.-% of a
polyamide.
25. A continuous method for producing a composite material of claim
18, comprising initially arranging UD fibers of layer A adjoining
each other on a circulating endless band a fiber nonwoven layer B
is laid thereon, and subsequently, layers A and B are needled to
each other.
26. The continuous method of claim 25, wherein prior to needling, a
nondirectional fiber layer C is laid onto layer B, and subsequently
the layers A, B and C are needled to each other.
27. The continuous method of claim 25, wherein UD fibers of layer A
are initially arranged on a circulating endless band, endless
fibers of layer B are laid thereon from traversing feeders, and
subsequently the layers A and B are needled to each other.
28. A process for producing fiber reinforced composite components,
comprising pressing a pre-cut part made of a composite material of
claim 16 in a mold at temperatures above the softening point of the
thermoplastic of randomly oriented fiber layer B.
29. A process for producing a thermoplastically moldable planar
semifinished product, comprising pressing a composite material of
claim 16 in a double band press at a temperature above the
softening point of the thermoplastic of randomly oriented fiber
layer B.
30. A process for producing components, comprising pressing a
pre-cut part made of a composite material of claim 16 together with
a GMT or NMT semifinished product in a mold at a temperature above
the softening point of the thermoplastic of randomly oriented fiber
layer B.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is the U.S. National Phase of PCT Appln.
No. PCT/EP2013/054844 filed Mar. 11, 2013 which claims priority to
European Application No. EP 12158958.4 filed Mar. 9, 2012, the
disclosures of which are incorporated in their entirety by
reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a planar composite material having
at least one layer A made of unidirectional reinforcing fiber
rovings and at least one layer B made of a thermoplastic fiber
nonwoven or a thermoplastic oriented fiber layer which can
optionally contain reinforcing fibers, wherein the layers A and B
are needled to each other.
[0004] 2. Description of the Related Art
[0005] Thermoplastics are increasingly being used for producing
components, particularly components for automobiles, due to their
low weight. To provide them with a sufficient rigidity and strength
they are usually compounded with reinforcing fibers. For example,
planar semifinished products are produced from glass mat reinforced
thermoplastics (GMT semifinished products) by merging endless glass
fiber mats and thermoplastic molten sheets and consolidating on a
double band press. However, this procedure requires a high energy
expense because the relatively viscous melt has to be pressed into
the mat at pressures far above 1 bar. Moreover, the fiber
reinforcement is nondirectional, while in the automotive field
reinforcement in one or several preferred directions is
particularly desired.
[0006] This is the case with the composite material according to WO
2006/111037. Therein, there is described a thermoplastically
moldable composite material comprising a fiber nonwoven layer made
of thermoplastic fibers and optionally reinforcing fibers and a
woven or oriented layer made of reinforcing fibers which are
preferably needled to each other. Oriented fiber layers are
prefabricated fiber structures in which several layers of
unidirectional fiber rovings are tightly and firmly knitted to each
other by means of stitching threads. The production of such fiber
structures is quite complex and, moreover, the rovings are not
sufficiently opened up during needling of the layers due to the
tight binding of the rovings by the stitching threads so that they
are only insufficiently and irregularly impregnated with the
thermoplastic, whereby the mechanical properties of the molded
article thus produced are negatively affected.
[0007] EP-A 323 571 relates to a fiber reinforced,
thermoplastically moldable semifinished product which contains a
planar fiber structure that is fixed by needling, consisting of:
[0008] at least two layers A made of oriented endless fibers having
an areal weight of maximally 300 g/m.sup.2, and [0009] at least one
layer B made of non-oriented fibers.
[0010] The textile planar part of EP-A 323 571 preferably contains
glass fibers, but other fibers such as carbon fibers and fibers
made of aromatic polyamides or other thermoplastics are also
mentioned. However, it is not specified whether these thermoplastic
fibers may be present in layer A or in layer B or in both layers.
For producing the semifinished product, the textile planar part is
subjected in a second, separate process step to impregnating with a
thermoplastic melt and pressing to a solid semifinished product so
that in the subsequent third step the semifinished products can be
processed to thermoplastic components. To ensure good impregnation,
EP-A 323 571 mandatorily requires that the areal weight of the
layer(s) A shall not be greater than 300 g/m.sup.2.
[0011] GB 2 237 583 describes a process for producing a prepreg
wherein thermoplastic binding fibers are continuously scattered
onto unidirectional reinforcing fibers and consolidated with the
same and thereby pressed to a profile part or a planar semifinished
product. There is no mention of needling.
[0012] It was thus an object of the invention to provide composite
materials on the basis of unidirectional fiber rovings that do not
have these disadvantages and can directly be processed to molded
parts without requiring a separate second process step after
production of a textile structure such as required according to
EP-A 323 571.
SUMMARY OF THE INVENTION
[0013] It has now been found that these and other objects are
achieved by directly using--instead of an oriented fiber
layer--discrete reinforcing fiber rovings that are not connected to
each other (so-called "unidirectional fibers", hereinafter referred
to as "UD fibers") and needling these together with a fiber mat
with randomly oriented fibers.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] Therefore, the subject of the invention is a planar
composite material comprising [0015] A. at least one UD fiber layer
having an areal weight of more than 300 to 2,000 g/m.sup.2 made of
discrete, unidirectional reinforcing fiber rovings which are not
connected to each other, and [0016] B. at least one fiber mat with
randomly oriented fibers B having an areal weight of 100 to 2,000
g/m.sup.2 made of a thermoplastic fiber nonwoven or a thermoplastic
oriented fiber layer which can contain up to 70 wt.-% reinforcing
fibers, wherein the layers A and B are needled to each other.
[0017] The composite materials of the present invention preferably
comprise the layer sequence A-B, but in principle also other layer
sequences, for example A-B-A or A-B-A-B, are possible.
[0018] In a first, preferred embodiment of the invention, the fiber
mat with randomly oriented fibers B consists of a thermoplastic
fiber nonwoven, e.g. a needle nonwoven or a non-needled carding or
airlay nonwovens having areal weights of 100 to 2000 g/m.sup.2,
preferably 200 to 1,200 g/m.sup.2, and particularly 300 to 1,000
g/m.sup.2. The thermoplastic fiber nonwoven consists preferably of
100% thermoplastic fibers, but it can also contain up to 70 wt.-%,
particularly 30 to 70 wt.-% reinforcing fibers. Both the
thermoplastic fibers and the reinforcing fibers preferably have a
length of 20 to 100 mm.
[0019] As thermoplastic fibers of the randomly oriented fiber layer
B, any spinnable thermoplastic can be used, but the thermoplastics
preferably comprise polypropylene having a MFI (230.degree. C.,
2.16 kp) of 25 to 150 g/10 min, particularly unmodified, i.e.
polypropylene without carboxyl groups, and also polyamides such as
polyamide-6 and polyamide-6,6, but furthermore also linear
polyesters, polysulfones, polyketones and polyetherimides. The
thermoplastic fibers are intended as "binding fibers", i.e. they
should be thermoplastically moldable into a matrix in the course of
subsequent processing of the composite material of the present
invention.
[0020] Preferred reinforcing fibers are glass fibers and carbon
fibers, but furthermore also natural fibers and basalt fibers as
well as fibers of higher melting thermoplastics such as aramide are
suitable. In the present context, the term "high melting" is to be
understood in relation to the thermoplastic fibers that are
provided as binding fibers, i.e. for the formation of a polymer
matrix. In particular, the melting or softening point of the
reinforcing fibers in the randomly oriented fiber layer B shall be
significantly higher, for example at least 50.degree. C. higher,
than that of the thermoplastic fibers.
[0021] In addition, the composite material can contain a relatively
thin fiber layer C made of nondirectional reinforcing fibers having
an areal weight of 50 to 500 g/m.sup.2, preferably of 100 to 300
g/m.sup.2 on the side of layer B which is facing away from layer A,
thus resulting in a layer sequence A-B-C. This layer C provides an
additional reinforcement of the composite material, which becomes
important when a fiber nonwoven having a relatively low areal
weight is used. Glass fibers or carbon fibers are particularly
useful as nondirectional fibers.
[0022] In a second embodiment, the fiber mat with randomly oriented
fibers B consists of a thermoplastic oriented fiber layer with
endless thermoplastic fibers which optionally can also contain
endless reinforcing fibers. Preferred thermoplastic fibers are
polypropylene fibers with a titer of 600 to 2,400 dtex, which can
be finished with generally known stabilizers and adhesion
promoters.
[0023] It is preferred for the composite material to comprise
exclusively layers A and B, and optionally C, but no further layers
of other type.
[0024] The composite material of the present invention preferably
contains 30 to 80 wt.-%, particularly 50 to 70 wt.-% UD fibers. Its
areal weight is preferably more than 400 to 4,000 g/m.sup.2,
particularly 1,000 to 1,000 g/m.sup.2. In the non-consolidated
state the thickness is preferably 5 to 15 mm.
[0025] The reinforcing fiber rovings are, for example, glass,
carbon, aramide or basalt fibers with a titer of preferably 100 to
4,800 tex, particularly 200 to 3,000 tex. Particularly preferred
are carbon fibers. Composite materials on this basis have a
particularly high rigidity in the longitudinal direction and a very
good flexibility.
[0026] The areal weight of the layer A is more than 300 to 2,000
g/m.sup.2, preferably 350 to 2,000 g/m.sup.2. Components that are
produced from composite materials with relatively heavy UD fibers
exhibit better strengths than those produced with light UD fibers
as described, for example, in EP-A 323 571. Moreover, such heavier
composite materials, particularly if they have only two layers A-B,
can be better handled than lighter ones.
[0027] Particularly preferred composite materials contain carbon
fibers as the UD fibers, and the fiber nonwoven layer contains a
polyamide, particularly polyamide-6, as the thermoplastic, and also
30 to 70 wt.-% carbon fibers. For this purpose, it is advantageous
to use recycled carbon fibers which, for example, were obtained by
means of known recycling methods from crushed, finished parts
reinforced with carbon fibers. Such composite materials have a good
temperature resistance.
[0028] An implementation of the method for producing composite
materials according to the first embodiment is shown in FIG. 1 as a
perspective view. Initially, a fiber nonwoven layer is produced
according to the carding or airlay method and needled to form a
needle nonwoven 2. The UD fibers 6 are initially laid out next to
each other on a circulating endless band (4), preferably as closely
to each other as possible, thereby forming a layer A. Thereupon,
the prefabricated needle nonwoven 2 is then continuously laid out
to form a layer B, and the two layers A, B are then needled to each
other in a needling device 8.
[0029] It is also possible to lay out a nonwoven produced according
to the airlay or carding method directly onto the UD fibers without
needling, and to needle thereafter only.
[0030] If the composite material shall contain further layers A or
B, respectively, the corresponding webs can be additionally fed and
needled.
[0031] If the composite material shall additionally contain a thin
layer C, the randomly oriented fibers 10 of the layer C are
arranged as endless mats onto the fiber nonwoven of the upper layer
B or scattered thereon as chopped fibers. All the three layers are
then needled to each other. This is schematically shown in FIG.
1.
[0032] FIG. 2 shows in a perspective view a further implementation
of the method for producing composite materials according to the
second embodiment. The UD fibers 6 of layer A are initially laid
out on a circulating endless band 4, then the thermoplastic fibers
12 and optionally also reinforcing fibers from traversing feeders
14 are laid out thereon by formation of an oriented fiber layer 16
corresponding to layer B, and the layers A, B are subsequently
needled to each other in a needling device 8. This is schematically
shown in FIG. 2.
[0033] The composite materials of the present invention can be cut
into thin plates. These pre-cut parts can then be directly
processed into three-dimensional components by pressing them in a
mold at temperatures above the softening point of the thermoplastic
of the randomly oriented fiber layer B. However, also a
semifinished product can be produced by continuously consolidating
the planar composite material web e.g. on a double band press at
temperatures above the softening point of the thermoplastic of the
randomly oriented fiber layer B and at pressures of 0.5 to 5 bar.
Pressing on laminating devices is also possible. The consolidated
semifinished product preferably has a thickness of 0.3 to 5.0 mm,
particularly 1.0 to 3.0 mm. It is also possible to use pre-cut
parts made of the composite materials for specific reinforcement of
fiber composite molded parts by inserting these into a mold
together with e.g. GMT or NMT semifinished products (i.e.
semifinished products on the basis of glass mat reinforced or
natural fiber mat reinforced thermoplastics) and needling together
with the same. It should be evident, as disclosed previously, that
when a layer is initially formed from continuous fibers and
subsequently needled, all or a large number of such fibers will no
longer be continuous or natural, "continuous" refers to the initial
state of the fibers, prior to needling.
[0034] The finished parts which are produced from the composite
materials of the present invention are very lightweight and highly
rigid. They can be used as automobile parts, for sporting goods,
for railway wagon construction and for aircraft construction.
* * * * *