CONSTITUANT COMPOSITE, NOTAMMENT CONSTITUANT COMPOSITE DE GARNISSAGE ET SON PROCEDE DE PRODUCTION

COMPOSITE COMPONENT, ESPECIALLY A COMPOSITE CLADDING COMPONENT, AND METHOD FOR PRODUCING THIS COMPONENT

Abrégé français

L'invention concerne un constituant composite dans lequel le matériau de renforcement se compose en totalité ou en partie de fibres naturelles recyclées, notamment de fibres de jute ou de sisal, constituées de tissus utilisés comme matériaux d'emballage. Entre 10 à 30 % d'autres matériaux fibreux ou de charges peuvent être mélangés à ces fibres de recyclage. Le matériau à base de fibres naturelles utilisé comme élément de renforcement est introduit de manière non dirigée, aléatoire, dirigée, moulée ou prémoulée. Il est également possible d'effectuer des combinaisons par stratification de l'élément de renforcement. On utilise comme liant des matières brutes synthétiques thermoplastiques ou des matières thermodurcissables ou une combinaison de matières thermodurcissables et de matières thermoplastiques ou un principe actif biologique. Selon l'invention, le matériau de départ est fractionné en morceaux de consistance coulante qui sont effilochés dans un broyeur.

Abrégé anglais

In the composite component of the invention, the reinforcing material consists
wholly or partly of recycled natural fibres, especially jute or sisal fibres,
produced from fabrics used as packaging materials. Said recycled fibres may be
mixed with between 10 and 30 % of other fibrous materials or fillers. The
natural fibre material used for reinforcement may be non-directional, randomly
structured, directional, moulded or pre-shaped. Combinations thereof are also
possible by layering the reinforcement insert. The binders used are
thermoplastic synthetic raw materials or duroplasts or a combination of
duroplasts and thermoplasts or a biological agent. According to the invention,
the raw material is crushed to form pieces of pourable consistency which are
broken down into fibres in a mill.

Revendications

CLAIMS:
1. A method for producing composite components, especially
composite cladding components, using a binder material having
a reinforcing material of natural fibers, characterized in
that carrying cloth comprising jute or sisal fibers,
especially sacks or old rags, are precomminuted into
rectangular and preferably square pieces of pourable and/or
flowable consistency, and these pieces are decomposed in a
mill by impact, rubbing or shearing into fibers with a length
of from 2 mm to 100 mm, and then these fibers are mixed or
needle-milled with a binder and/or with thermal fibers, and
from the conglomerate obtained, nonwovens or mats are made
that are heated to melt the thermal fibers and/or to dry
and/or cure or solidify the binder.
2. The method of claim 1, characterized in that the
precomminution is done by separating and cutting tools,
preferably by means of two veneer cutters, guillotines, sickle
choppers, or knife mills or granulators.
3. The method of claim 1 or 2, characterized in that the
precomminution is effected by a cutting machine, which is
equipped with at least one continuous transverse knife and
additionally has a row of longitudinal knives.
4. The method of one of claims 1-3, characterized in that the
decomposition into fibers is done with a hammer mill.
5. The method of one of claims 1-4, characterized in that the
comminuted material is moistened in an intermediate step.
6. The method of one of claims 1-5, characterized in that the
decomposition into fibers in a mill, powdered or
high-viscosity adhesive is simultaneously applied to the fibers.

7. The method of one of claims 1-6, characterized in that the
gluing of the fibers is done by atomizing the binder.
8. The method of one of claims 1-7, characterized in that
after the decomposition into fibers, up to 20 weight % of
thermal fibers are mixed in.
9. The method of one of claims 1-8, characterized in that
after the precomminution or the decomposition into fibers, a
sorting out of extraneous substances is done.
10. The method of one of claims 1-9, characterized in that
the coverings of the outer visible sides are provided with
openings.
11. A composite component, produced by the method of one of
claims 1-10, characterized by reinforcing material of natural
fibers, preferably recycled natural fibers, applied in layers
of reinforcing fibers having a length of 2 mm to 10 mm and
reinforcing fibers having a length of 10 mm to 100 mm.
12. The composite component of claim 11, characterized in
that the proportion of natural fibers is between 10% and 90%.
13. The composite component of claim 11 or 12, characterized
in that between 10% and 30% of other fiber materials or
fillers are admixed with the recycled fibers.
14. The composite component of one of claims 11-13,
characterized in that the reinforcing material can be
introduced in nonoriented, random, oriented, shaped or
preshaped form.
15. The composite component of claim 14, characterized in
that the reinforcing material can be introduced in the form of
a woven cloth or a nonwoven.

16. The composite component of one of claims 11-15,
characterized in that the composite component is made by
injection molding or by a pressing process.
17. The composite component of one of claims 11-16,
characterized in that at least one layer has a foam structure.
18. The composite component of one of claims 11-16,
characterized in that at least one outer visible side is
provided with a decorative material.
19. The composite component of claim 18, characterized in
that the decorative material is formed of film or foil,
carpeting, textile, leather, synthetic leather, or genuine
wood.
20. The composite component of claim 18, characterized in
that the decorative material is formed of fibers from annual
plants.
21. The composite component of one of claims 11-20,
characterized in that the reinforcing material located toward
the decorated side is formed of fibers having a length of from
2 to 10 mm, and the adjacent layer is formed of oriented or
nonoriented fibers having a length of from 10 mm to 100 mm.
22. The composite component of one of claims 11-21,
characterized by a raw density of from 10 kg/m3 to 75 kg/m3.

Description

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FILE, ~ ~ On2~2a342~2 1998-04 07
WO 96/37355 T~T~ANSLATION PCT/DE 96/00842
C~MPOSITE COMPONENT, ESPECIALLY COMPOSITE CLADDING COMPONENT,
AND METHOD FOR PRODUCING THIS COMPONENT
The invention relates to a method for producing a composite
component, especially a composite cladding components, using a
binder material having a reinforcing material of natural
fibers, and to a method for producing this component.
Cladding components of the type described are used in various
industrial fields and are intended to have not only a visual
function but also good mechanical properties. These include
high ~;men~sional stability as well as favorable temperature
behavior. Moreover, limited moisture absorption and the lest
possible weight are demanded. Because of the often complex
surface geometry, a high degree of freedom in the shaping
process is expected. The surface is provided with decorative
materials based on PVC, PVC/ABS, PUR, TPO, etc. as well as
decorating materials based on textiles, carpeting and leather.
The overall construction should have a minimum of noise-
abatement and/or heat-insulating properties and should be
capable of being made by a concept that is amenable to
recycling.
In the prior art, such cladding components are produced as
solid plastic parts or as fiber-reinforced press parts. They
either comprise wood fiber materials with a duroplastic
binder, or thermoplastic injection molded or pressed parts
with reinforcement inlays of synthetic or natural fiber
materials. The wood fiber materials have only limited
mechanical properties. The use of synthetic reinforcing
fibers puts a burden on the work area and has health risks.
The use of natural fibers, because of the various processing
methods, leads to quality fluctuations, as well as high cost
because of the still only slight availability and increased
demand.

CA 02234252 1998-04-07
WO 96/37355 PCT/DE 96/00842
Qne known production process provides for foaming the back of
a preformed decorative part. This is a multistage and hence
expensive method, in which the cross-linked foam causes
considerable recycling problems. In German Utility Model G 93
01 022.2, an inner cladding element is described, which
comprises a wood fiber composite material, is three-
~;mensionally deformed in a first step, and is coated with a
decorative material in a further method step. The multi-stage
procedure is complicated and expensive, and the level of
properties limits its versatility. German Patent Disclosure
DE 41 19 295 A1 describes the use of iU~e fibers, threads and
woven cloths, among others. In comparison to recycled jute,
these materials are expensive and because large quantities
have to be added they have major cost disadvantages. In
German Patent Disclosure DE 42 29 078 A1, the use of a
recycled jute fiber as an additive in asphalt production is
described. The fiber length is given as a maximum of 4 mm and
preferably 1 to 2 mm.
These fiber lengths are markedly too short to assure adequate
reinforcement and stabilization. Precisely the production of
a longer fiber product is the prerequisite for producing
heavy-duty cladding components.
From German Patent Disclosure DE 41 39 257 Al, a recycled
plastic molding composition is known, with which to increase
the strength reinforcing fibers are admixed, the reinforcing
fibers being formed of glass fibers. The fiber lengths are
said to be between 1.25 mm and 4.5 mm. With this kind of
fiber length, adequate stabilization cannot be attained.
The object of the invention is to create a composite
component, especially a composite cladding component, which
can be produced economically while assuring adequate strength
for the d~m~n~s made of it.

CA 022342~2 1998-04-07
WO 96/37355 PCT/DE 96/00842
This object is attained according to the invention by a
reinforcing material formed either entirely or in part of
recycled natural fibers, especially jute or sisal fibers. The
overall costs for the composite component can be markedly
lowered, if recycled jute or sisal fibers originating the
processing of packaging materials are used. These products
are available worldwide in adequate quantities. Jute fiber,
after cotton fiber, is the most frequently cultivated natural
fiber product. The fibers are CO2-neutral and are already
available in the packaging field in a favorable starting form
for further use. The starting product has overly coarse
fibers, however, and in further processing would lead to
metering problems as well as demixing between the fiber
ma~erial and the binder resin system in difficult contour
regions. These fibers are therefore first, beginning with the
cloth structures, processed in a multistage process into
fibers with a length of from 2 mm to 100 mm and then deformed,
as individual fibers or as a cloth composite made from them
with a binder resin system, to make a tt. To vary the
mechanical properties, the jute or sisal fibers may also have
small quantities (10~ to 30%) of other natural fibers added,
such as ~lax, hemp, ramie, kenaf, Chinese reed, cotton, or
coconut, as well as such fillers as wood fibers or shavings.
The processing can be done by injection molding or pressing.
The natural fiber material used as a reinforcing inlay may be
introduced in nonoriented, random, oriented, shaped or-
preshaped form. Combinations are also possible by forming
layers in the reinforcing inlay. In a further embodiment, the
reinforcing material located toward the decorated side is
formed of short fibers, and a second layer is formed of
oriented or nonoriented long fibers. The short fibers
preferably have a length between 2 mm and 10 mm, and the long
fibers a length between 10 mm and 100 mm. As the binder
resin, materials based on natural substances (starch products,
PHB, CA, CAB, PU, PHA, PHB, PCL, etc.), thermoplastic

CA 022342~2 1998-04-07
WO 96/37355 PCT/DE 96/00842
materials (such as PP, ABS, PC/ABS, PA, PET), and duroplastic
systems (such as epoxy resin3, as well as combinations of
duroplastics and thermoplastics, are predominantly used.
Expediently, a slow-reacting duroplastic should be used, which
is adjusted such that it cures only after the deformation has
been done and then finally fixes the shape. The weight of the
finished part can be reduced markedly by adding a propellant
system to these materials and hence foamed materials. The
adhesion among these materials and the natural fibers can be
improved by adding adhesion promoters. The recycled fibers
can be varied in their pattern of properties by the addition
of other natural fibers, such as flax, hemp, sisal, ramie,
kenaf, etc.
The decorating materials are either placed directly in the
production tool as well and bonded to the carrier material in
the deformation operation, or applied in a method step
following the deformation operation. The decorative material
may be formed of film, carpeting, textile, leather, synthetic
leather or genuine wood. In a preferred embodiment, the
decorative material is formed of fibers of annual plants. The
raw density of the components of the invention ranges between
10 kg/m3 and 75 kg/m3.
By the production method of the invention, old jute or sisal
sacks or old rags are precomminuted into rectangular and
preferably square pieces of bulk-goods and/or flowable
consistency, and these pieces are decomposed in a mill into
fibers, and then these fibers are mixed or needle-milled with
a binder and/or with thermal fibers, and from the conglomerate
obtained, nonwovens or mats are made that are heated to melt
the thermal fibers and/or to dry and/or cure or solidify the
binder. In a feature of the invention, the precomminution is
done by separating and cutting tools, preferably by means of
two veneer cutters, guillotines, sickle choppers, or knife
mills or granulators. Expediently, the precomminution is

~ CA 022342~2 1998-04-07
W~ 96/37355 PCT/DE 96/00842
e~fected by a cutting machine, which is equipped with at least
one continuous transverse knife and additionally has a row of
longitudinal knives. The breakdown into fibers can be done by
mills that perform the breakdown by impact, friction or
shearing. The decomposition into fibers is especially
advantageous with a hammer mill. Advantageously, the
comminuted material is moistened in an intermediate step. In
a further method step of the invention, the decomposition into
fibers in a mill, powdered or high-viscosity adhesive is
simultaneously applied to the fibers, and the gluing of the
fibers is done by atomizing the binder. After the
decomposition into fibers, up to 20 weight % of thermal fibers
may be mixed in. The sorting out of extraneous materials is
expediently done after the precomminution or the decomposition
into fibers. The possibility exists of providing the
coverings of the outer visible sides with openings.