WO1989005366A1

WO1989005366A1 - Process for manufacturing storable, easily handled fibre mats

Info

Publication number: WO1989005366A1
Application number: PCT/AT1988/000107
Authority: WO
Inventors: Wolfgang Privas
Original assignee: Kühnsdorfer Holzfasermattenwerk Pacht- Und Betrieb
Priority date: 1987-12-11
Filing date: 1988-12-05
Publication date: 1989-06-15
Also published as: ES2009426A6; ATA326887A; AT387798B; CA1321512C; YU45065B; PL276317A1; PL159294B1; PT89196B; YU222788A; CN1034403A; CN1008752B; ZA889242B; PT89196A; CS8808146A2; CS275642B6

Abstract

A process is useful for manufacturing a storable, easily handled fibre mat (24) made of cellulose fibres (1) and thermoplastic fibres (10), in particular polyester fibres, and/or natural fibres of vegetable origin, and containing a thermosetting binder (5) made of plastic. During the application of heat and pressure and setting of the thermoplastic binder in a later step of the process, the fibre mat (24) can be compressed to form dimensionally stable pieces which possess uniform properties over their entire cross-section. For this purpose, the cellulose fibres (1) are impregnated with a solution of the thermosetting binder (5), preferably a phenol resin solution, and then dried; the dried cellulose fibres (6) are dry mixed with thermoplastic fibres (10), for example polyester fibres, and/or natural fibres of vegetable origin; a nonwoven (21) is made from the mixture of cellulose fibres (6) and thermoplastic fibres (10) and/or natural fibres of vegetable origin, and the nonwoven (21) is reinforced by needles in a needle machine (23).

Description

Process for producing a storable, manageable fiber mat

The invention relates to a process for producing a storable, manageable fiber mat, which is formed from cellulose fibers and thermoplastic fibers, in particular polyester fibers, and / or natural fibers of vegetable origin, and contains a thermosetting binder based on plastic, which fiber mat is suitable under the action of heat and pressure and with hardening of the thermosetting binder in a later process step to be pressed into form-retaining workpieces.

Under the influence of heat and pressure during the compression molding process, the thermosetting binder hardens and the thermoplastic fibers form heat-sealing joints between the fibers, which also harden after cooling and give a smooth surface.

It is known (DE-A - 32 39 732) to form a manageable fiber mat of the type described above by heating a nonwoven fabric made from cellulose fibers and thermoplastic fibers and optionally further thermoplastic materials or a thermosetting binder in such a way that the thermoplastic fibers up to soften to their adhesive point, whereby the fibers are fixed to each other at the points of contact by gluing and the fiber mat is pre-consolidated.

When the nonwoven is strengthened by melting the thermoplastic fibers, the result is a nonwoven with properties that are very different across the cross section, especially since the nonwoven is most strongly heated on the surface layers. You want to Ensure that the central layers stick together, it is no longer ensured that the surface layers still have a fibrous structure and that the fiber mat is flexible enough for further handling.

In the fiber mat according to DE-A - 32 39 732, the binders responsible for the hardening of the fiber mat are only mixed with the fibers, so that uniform hardening cannot be ensured. In particular, areas can arise in which binders are present in insufficient quantities, so that the finished workpiece does not have the same strength at every point.

A method for producing a fiber mat is also known from DE-B - 1 054 416. According to this document, a mixture of cellulose fibers and synthetic fibers is processed into a nonwoven fabric, which is solidified by applying adhesive and then drying and pressing. Here, the fibers of the surface layers are glued together at the contact points, so that the nonwoven fabric is stabilized and can be subjected to further processing.

This known method has disadvantages, which can be seen in the fact that the application of bonding agents to the surface of a nonwoven fabric is difficult to carry out and requires subsequent drying. In addition, the nonwoven fabric has very different strength properties across the cross section, since impregnation of the nonwoven fabric with adhesive is only provided on its surface layers. A complete impregnation requires an even more complex aftertreatment, in which the nonwoven fabric which has not yet dried must be treated with corresponding care. According to DE-B - 1 054 416, the pressed workpiece is solidified by introducing synthetic resin powder into the cavity of the press deforming the fiber mat. In order to obtain a uniformly solidified workpiece, the synthetic resin powder must be introduced into the press in a uniformly thick layer, but this is very difficult, if at all, to be achieved with more complicated shapes of the workpiece.

The invention aims to avoid these disadvantages and difficulties and has as its object to provide a method for producing the fiber mat described above, which results in a homogeneously solidified fiber mat with uniform properties over the cross section and can be carried out with little energy expenditure. In addition, the production of uniformly consolidated workpieces from this fiber mat should be ensured.

This object is achieved by the combined

Application of the following measures solved: that the cellulose fibers with a solution of the thermosetting binder, preferably one

Phenolic resin solution, impregnated and dried, that the dried cellulose fibers with thermoplastic fibers, such as polyester fibers, and / or

Natural fibers of vegetable origin are mixed dry, that a fleece is formed from the mixture of cellulose fibers and thermoplastic fibers and / or natural fibers of vegetable origin and the fleece formed is consolidated in a needle machine by needles.

If the processing of the fiber mat takes place with particularly strong deformation of the fiber mat, the mixture of cellulose fibers and thermoplastic fibers and / or natural fibers of vegetable origin needled onto a thin carrier fleece made of thermoplastic fibers.

A particularly uniform fiber mat can preferably be produced by forming a fleece from impregnated cellulose fibers and a fleece from thermoplastic fibers and / or natural fibers of vegetable origin, which nonwovens are mixed in a drum, another fleece is formed from the mixture and applied to a thin one Backing fleece made of thermoplastic fibers is needled.

A fiber mat produced according to the invention, preferably for the production of objects molded using heat and pressure, with cellulose fibers, thermoplastic fibers and / or natural fibers of vegetable origin and a thermosetting binder based on plastics, is characterized in that the cellulose fibers are impregnated with a solution of the thermosetting binder are and are connected to the thermoplastic fibers and / or natural fibers of vegetable origin by mechanical devouring without melting.

For particularly high loads on the fiber mat, the cellulose fibers and thermoplastic fibers and / or natural fibers of vegetable origin are expediently mechanically bonded to a thin carrier fleece made of thermoplastic fibers.

An article molded from a fiber mat according to the invention using heat and pressure is characterized in that the cellulose fibers, thermoplastic fibers and / or natural fibers of vegetable origin in a hardened melt of thermosetting binder are embedded and connected by this melt.

Cellulose fibers are advantageously crosslinked with the carrier fleece and the hardened melt made of thermosetting binder, as a result of which the object has a particularly high strength and a highly stressable surface. An object of this type also has high dimensional stability and high bending pressure values.

The method according to the invention is explained in more detail below with reference to the accompanying drawing, with FIGS. 1 and 2 each illustrating a method diagram for producing the fiber mat. In Fig. 3 an article made from a fiber mat according to the invention is shown in oblique view. Fig. 4 shows this object in section, which is guided along the line IV-IV of Fig. 3. Fig. 5 shows a detail section through this object in a large magnification.

1, chips 1 are processed into cellulose fibers 3 by defibrating in a defibrator 2. These are impregnated with wax 4 and a phenolic resin solution 5. The impregnated cellulose fibers 6 are then dried in a tube dryer 7 and pressed into bales 9 in a press 8.

Thermoplastic fibers 10, etc. Polyester fibers are disintegrated from polyester fiber bales 11 and transported to a fiber scattering machine 13 via an intermediate bunker 12. The fiber scattering machine 13 spreads the polyester fibers 10 onto a conveyor belt 14. Cellulose fibers, which are formed by disintegrating the bales 9, are scattered onto this layer of polyester fibers by means of two further fiber scattering machines 15, 16.

The sandwich thus formed is placed in a mixer 17 premixed and further mixed in a fine mixer 18. The mixture 19 is transported to a nonwoven laying machine 20, in which a nonwoven fabric 21 is formed with a predetermined weight. This fiber fleece 21 is applied to a thin polyester fleece 22 and needled in a needle machine 23. The fiber mat 24 produced in this way is then cut in a cutting and stacking device 26 to a predetermined format and stacked.

The nonwoven fabric is very easy to handle and yet soft and flexible, so that it does not cause any difficulties when it is further processed into a molded article. If 10 natural fibers of vegetable origin (e.g. cotton) are used instead of the thermoplastic fibers or such natural fibers are mixed with thermoplastic fibers, this also results in a soft and flexible nonwoven fabric.

According to the method shown in FIG. 2, the processing of the wood chips 1 to impregnated cellulose fibers 6 and the polyester fibers 10 takes place in the same way as in the method shown in FIG. 1; however, the formation of nonwoven occurs differently. The cellulose fibers 6 are guided to the fleece laying machine 20 via a conveyor belt 14. The polyester fibers 10 reach their own fleece laying machine 28 via a conveyor belt 27. In this way, both the cellulose fibers and the polyester fibers form their own fleece 29, 30.

The two non-woven fabrics 29, 30 are brought together and mixed in a drum 31. A fleece 21 is in turn formed from this mixture and is applied to a thin polyester fleece 22. In the subsequent needle machine 23, the nonwoven fabric 21 with the thin Polyester fleece 22 needled, which in turn forms an easily manageable but sufficiently deformable fiber mat 24.

Objects are made from the fiber mats 24 by pressing using heat and pressure. Such an object 32 is shown for example in FIGS. 3 and 4. It represents a door trim for a passenger car. As can be seen from FIG. 4, this door trim 32 has approximately the same wall thickness over the entire cross section.

5, a section through the object 32 is shown greatly enlarged in detail. The cellulose fibers 6 can be seen, which are embedded in hardened melt 33 made of thermosetting binder. The outer boundary of the object 32 is formed on one side 34 by a carrier fleece 22 made of thermoplastic fibers 35, which is not only mechanically connected to the cellulose fibers 6, but it is the cellulose fibers 6 with the carrier fleece 22 and the hardened melt 33 made of thermosetting binder , which penetrated into the carrier fleece 22 during the pressing process, networked to form a rigid, durable and dimensionally stable structure.

In the hardened binder, thermoplastic fibers 36 or natural fibers, if such are used in addition to the thermoplastic fibers 36 or instead of these thermoplastic fibers 36, are additionally embedded.

Claims

Claims:

1. Process for the preparation of a storable. Manageable fiber mat (24), which is formed from cellulose fibers (1) and thermoplastic fibers (10), in particular polyester fibers, and / or natural fibers of vegetable origin, and contains a thermosetting binder (5) on a plastic basis, which fiber mat (24) is suitable, under the action of heat and pressure and with hardening of the thermosetting binder (5) in a later process step to be pressed to form-retaining workpieces, characterized in that the following measures are used in combination:

that the cellulose fibers (1) are impregnated and dried with a solution of the thermosetting binder (5), preferably a phenolic resin solution,

that the dried cellulose fibers (6) are dry mixed with thermoplastic fibers (10), such as polyester fibers and / or natural fibers of vegetable origin,

- That from the mixture of cellulose fibers (6) and thermoplastic fibers (10) and / or natural fibers of vegetable origin a fleece (21) is formed and

- The fleece formed is solidified in a needle machine (23) by needling.

2. The method according to claim 1, characterized in that the mixture of cellulose fibers (6) and thermoplastic fibers (10) and / or natural fibers of vegetable origin is needled onto a thin carrier fleece (22) made of thermoplastic fibers.

3. The method according to claim 1 or 2, characterized in that a fleece (29) made of impregnated Cellulose fibers (6) and a nonwoven (30) made of thermoplastic fibers (10) and / or natural fibers of vegetable origin are formed, which nonwovens are mixed in a drum (31), another nonwoven (21) is formed from the mixture and applied to a thin one Backing fleece (22) made of thermoplastic fibers is needled (Fig. 2).

4. fiber mat (24), preferably for the production of objects shaped using heat and pressure, with cellulose fibers (1), thermoplastic fibers (10) and / or natural fibers of vegetable origin and a thermosetting binder (5) on a plastic basis, characterized in that that the cellulose fibers (1) are impregnated with a solution of the thermosetting binder (5) and are connected to the thermoplastic fibers (10) and / or natural fibers of vegetable origin by mechanical entanglement without melting.

5. Fiber mat according to claim 4, characterized in that the cellulose fibers (1) and thermoplastic fibers (10) and / or natural fibers of vegetable origin are additionally mechanically connected to a thin carrier fleece (22) made of thermoplastic fibers.

6. From a fiber mat according to claims 4 or 5 using heat and pressure molded object (32), characterized in that the cellulose fibers (6), thermoplastic fibers (36) and / or natural fibers of vegetable origin in cured melt (33) are embedded from thermosetting binder and are connected by this melt (33).

7. Object according to claim 6, characterized in that Cellulose fibers (6) are cross-linked with the carrier fleece (22) and the hardened melt (33) made of thermosetting binder.