EP1743970B1 - Parallelepipedic product of mineral fibres - Google Patents

Abstract

The product has fibers aligned parallel to a main upper surface (H1) of the product, where the fibers have a set of layers running below an angle between 10 and 80 degree to a longitudinal side of the upper surface. Each of the layers lies in-between the fibers at a corresponding section, and primary fleece layers (PV) are arranged one above the other. The layers of the adjacent fibers of the adjacent fleece layers have an orientation, and the adjacent fibers cross the adjacent fleece layers.

Description

The invention relates to a cuboidal mineral fiber product. The term "cuboid" according to the invention is not to be understood in the strict geometric sense, but technically. A mineral fiber mat or mineral fiber plate formed from a mineral fiber web usually consists of very thin and short vitreous fibers which are fixed to one another via a binder, such a product usually having an open porosity of more than 80% by volume. Accordingly, the surfaces of such products are not exactly planar, but correspond to the arrangement of the individual fibers. Likewise, for example, in the case of a mineral fiber board, the two main surfaces do not run exactly perpendicular to the four circumferential further surfaces. All of these products have been subsumed under the term "cuboid" and regardless of their respective ratio of width: thickness: length.

The term "mineral fiber product" includes products of glass wool fibers, rockwool fibers, slag wool fibers or the like. Likewise, mixtures of the aforementioned fibers with foreign fibers, such as synthetic fibers, or natural fibers, such as hemp fibers, from the term mineral fiber product comprises.

First and foremost, a mineral fiber product according to the invention refers to certificates of mineral fibers bound with a binder or binding fibers; but it should also be such products are included, which were assembled in other ways to the aforementioned cuboid shape, for example by needling (felting).

Mineral fiber products of the aforementioned type are produced, for example, as follows:

A mineral melt (or molten glass) is poured over a so-called spinner. These are fast rotating rollers. Upon impact of the melt on the peripheral surface of such a rotating roller fibers are formed, which are carried away via an air flow and led away after wetting with a binder as a so-called primary non-woven on a conveyor belt. The fibers within this very thin primary web are predominantly parallel to the large surfaces of the primary web.

By a pendulum-like movement, the primary non-woven is processed into a multi-layer secondary non-woven, with adjacent Primärvliesschichten overlap. The removal of the primary web takes place perpendicular to the transport of the primary web. It follows that the predominant fiber orientation within the multilayer secondary web is parallel to its main surfaces and perpendicular to the transport direction of the secondary web.

The above information on fiber orientations in the primary nonwoven and secondary nonwoven are to be understood in the sense of a preferred fiber orientation and not in the strictly mathematical / geometric sense. This already arises from the type of fiber formation described above and the transport of the fibers via an air stream.

The secondary web is guided in the further production path as a continuous web over a processing line. In this case, for example, the density of the product can be adjusted. For this purpose, counter-rotating rollers are known, between which the web is guided. The processing section usually also includes a curing oven in which the binder is cured. It also often includes a cutting station, along which the desired final geometry (cuboid geometry) can be created.

A disadvantage of these standard products is the low compressive strength perpendicular to the main surfaces due to the described preferred fiber orientation. For example, for a product having a bulk density of about 150 kg / m ³ , this compressive strength (δ _D1 ) is only 70 to 100 kPa.

Greater is the compressive strength in a direction parallel to the major surfaces. There are two directions: δ _D2 describes the compressive strength with respect to a force acting perpendicular to such narrow sides of the secondary web, which run in the direction of transport of the secondary web during manufacture. δ _D3 defines the compressive strength perpendicular to δ _D2 , ie the force is perpendicular to a surface that was perpendicular to the transport direction of the secondary non-woven fabric during manufacture. Concerning the nomenclature is complementary Fig. 1 directed. δ _D2 can be 170-220 kPa in the prior art, δ _D3 about 120-150 kPa, again relative to the bulk density of about 150 kg / m ³ .

The thermal conductivity (according to ÖNORM B 6015-1 ff) of these products is usually around 0.04 W / mK. This is especially true in directions perpendicular to the major surfaces.

There has been no lack of attempts to influence the compressive strength of such mineral fiber products by changing the predominant (preferred) fiber orientation.

In the CH 620 861 It is proposed to compress the mineral fiber layer (the secondary web) along the above-illustrated processing section in its thickness and length, so as to achieve a mutual bulging of the secondary web and a reorientation of the preferred fiber direction.

According to DE 23 07 577 C3 the mineral fiber web is cut into longitudinal strips and these strips are turned by 90 ° about their longitudinal axis and then joined together and connected via a binder to a cuboid overall body. In this way, the finished mineral fiber product obtains a preferred fiber orientation perpendicular to the major major surfaces.

The method according to CH 620 861 is relatively easy to do; however, the fibers remain substantially in alignment parallel to the major surfaces. The compressive strength can only be improved slightly, the thermal conductivity increases. The method according to DE 23 07 577 C3 Although leads to cuboidal mineral fiber products increased compressive strength (perpendicular to the major major surfaces); however, the process is expensive. The thermal conductivity does not improve significantly.

The invention has for its object to provide a cuboid mineral fiber product, which shows good thermal resistance at the same time advantageous values with respect to thermal conductivity, namely in all 3 directions of the coordinate system (that is, each perpendicular to the pairwise opposite surfaces of the cuboid body).

The invention is based on the following finding:

The various prior art measures all relate to fiber products where the preferred fiber orientation is generally parallel or perpendicular to at least two opposing surfaces of the product. This is true even if the fibers are reoriented, as in the DE 23 07 577 C3 is suggested by first cutting the web into strips and then rotating the strips through 90 °.

The invention detaches itself from this deadlocked view and proposes a cuboidal mineral fiber product comprising a plurality of superposed primary nonwoven layers (PV, PVR) characterized by at least one primary nonwoven layer (PVR) having sections (AL, AR) with different fiber orientations which together about V-shaped image for the fiber flow within the primary nonwoven layer (PVR) result.

A further embodiment of the present invention relates to a cuboidal mineral fiber product, the fibers of which are oriented substantially parallel to a product surface and extend predominantly at an angle of <80 ° and> 10 ° to longitudinal sides of this product surface.

Thus, a targeted "skew" of the fibers within a plane parallel to a product surface is proposed. This is achieved in particular by a shift (change) in the fiber orientation direction (change in the orientation of the fibers) in the primary nonwoven. By creating a secondary web over a so-called pendulum ( DE 41 27 172 C2 ) primary nonwoven layers with alternating fiber orientation are superimposed, resulting in the desired effects in the secondary web and final product.

In this case, the fibers of individual regions can be oriented in one direction and other fibers (other regions) in a different direction, so that, for example, a V-shaped course or a type of "zigzag" of adjacent fibers within a plane (parallel to a product surface) occurs leaves.

The targeted oblique orientation of the fibers is according to alternative embodiments in the ranges <75 ° /> 15 ° or <70 ° /> 20 ° to the longitudinal sides of the respective product surface. The inclination can be 45 ° +/- 5 °.

In this case, the fibers formed essentially parallel to a product surface, in particular parallel to the two main surfaces, can have a predominantly opposite orientation along adjacent, strip-shaped zones. The above angle indications include an embodiment in which the fibers of one strip are at an angle of 45 ° to the longitudinal side of the product surface, while the fibers of the adjacent strip are oriented more or less perpendicular to these fibers, that is with opposite orientation, but also at an angle of 45 ° to the longitudinal side of the product surface. In this way, a kind of herringbone pattern develops within a plane parallel to a surface of a product according to the invention.

Due to the production outlined above, a generic mineral fiber product usually consists of a plurality of primary nonwoven layers arranged one above the other, even if these are no longer immediately recognizable as such (in particular after the product has passed through a hardening furnace). In this case, adjacent fibers of adjacent primary nonwoven layers may have a predominantly opposite orientation. This will be illustrated by an example:

Assuming, ideally, that a mineral fiber product is composed of 10 primary nonwoven layers, the fibers of 5 layers should extend at least partially at an angle between 10 and 80 ° to a longitudinal side of the product surface, while the fibers of the 5 intermediate layers on the corresponding sections have a substantially opposite orientation.

In this way, a uniform and advantageous "toothing" of the fibers can be achieved both within a single level and over the entire volume of the product. This leads to a favorable compressive strength at least in two of three directions of the coordinate system and also to advantageous values in terms of thermal conductivity.

Depending on the bulk density, binder content / fiber orientation, etc., it is possible to achieve thermal conductivities which are normal (normal) to the primary nonwoven layers <0.04 W / mK, in some cases <0.038 W / mK, although values of <0.036 W / mK in preliminary tests were found.

At the same time, the compressive strength of these mineral fiber products (at about 150 kg / m ³ bulk density) normal to the narrow sides of the product, ie δ _D2 and δ _D3 , could be determined to be around 150 kPa. The compressive strengths δ _D2 , δ _D3 vary in a product according to the invention only by about +/- 20% of an average of δ _D2 , δ _D3 , preferably by a maximum of +/- 15%, that is, the thermal conductivity is largely in both directions constant.

Other features of the invention will become apparent from the features of the claims and the other application documents.

FIG. 1 shows schematically a cuboid mineral fiber product according to the prior art, which has been cut out of a mineral fiber web formed in the preparation. It consists of two main surfaces H1, H2, two perpendicular to the original transport direction P of the secondary web (this is the transport direction of the secondary web perpendicular to the transport direction of the primary web) extending "large" narrow sides GS1, GS2 and two, parallel to the original transport direction P of the secondary web extending "small" narrow sides KS1, KS2.

The known mineral fiber product was produced in a known manner. The fibers collected in a chute were deposited on a conveyor belt in the form of a so-called primary web. The primary fleece was guided over a so-called pendulum. In this case, primary nonwoven layers are stacked one above the other with a certain degree of overlap and removed on a further conveyor belt in the transport direction P. Idealized results in the result of a fiber flow, as in FIG. 1 shown. The fibers F extend substantially parallel to the main surfaces H1, H2 and preferably perpendicular to the small narrow sides KS1, KS2. With PV different primary nonwoven layers are idealized (parallel to each other) shown.

The known product has a predetermined bulk density of about 150 kg / m ^3, a compressive strength δ _D1 perpendicular to the large main surfaces H1, H2 of about 70 to 100 kPa. The compressive strength δ _D2 (perpendicular to the small narrow sides KS1, KS2 is approximately 170 to 200 kPa, the compressive strength δ _D3 is approximately 120 to 150 kPa.

The fundamentally different structure of a mineral fiber product according to the invention results from FIG. 2 , The main surfaces and narrow sides are analogous to the FIG. 1 State of the art referred to, even if here the side surfaces GS1, GS2 are shown narrower than KS1, KS2.

It is important that the surface sections GS1, GS2 run perpendicular to the original production direction P of the secondary web and the side surfaces KS1, KS2 parallel to the original production direction P.

The individual primary nonwoven layers PV are shown running at an angle α to the main surface H2. This will become the FIG. 1 described overlap of primary nonwoven layers using the pendulum illustrated, but exaggerated. For better illustration, the connecting portions of adjacent primary nonwoven layers PV are not shown. These would run "predominantly parallel" to the side surfaces KS1, KS2 of the secondary nonwoven. In actuality, the angle α is only a few degrees and, as a result, the individual primary nonwoven layers PV run almost parallel to the main surfaces H1, H2, in particular when the mineral fiber web (secondary nonwoven web) has passed through rolls during production Compact secondary web.

Within the individual primary nonwoven layers, the preferred fiber progression according to the invention is dotted or dashed. The fiber profile according to the invention is illustrated schematically on the basis of 2 cutouts in the region of the primary nonwoven PVR shown on the right. Accordingly, the fibers shown in section AL extend predominantly at an angle β of about 45 ° to surface KS1 and the fibers represented in section AR approximately at right angles γ to the fibers at AL. This results in a total of approximately V-shaped image for the fiber flow within the primary nonwoven PVR in the supervision. Due to the oscillating placement of the primary web to the secondary web, the basic fiber orientation of the adjacent primary web is exactly the opposite (see schematic diagram of the primary web PVM).

This fiber orientation can be achieved in different ways:

The conveyor belt for the primary web can be divided into a plurality of conveyor belts running side by side, which run at different speeds and correspondingly change the orientation, in particular of the fibers, which lie in the border region of adjacent conveyor belts. In this case, adjacent fibers are entrained due to the bonding or entanglement of the fibers.

It can be provided air nozzles whose air flow changes the fiber orientation in the desired manner.

Claims (11)

1. Cuboidal mineral fibre product comprising several layers of primary nonwoven (PV, PVR) arranged one on top of the other, characterised by at least one primary nonwoven layer (PVR), which has sections (AL, AR) with a different fibre orientation that together result in an approximately V-shaped pattern for the fibre structure within the primary nonwoven layer (PVR).
2. Mineral fibre product according to claim 1, the fibres of which that are oriented substantially parallel to a product surface run predominantly at an angle of < 80° and > 10° to longitudinal sides of this product surface.
3. Mineral fibre product according to claim 1, the fibres of which that are oriented substantially parallel to a product surface run predominantly at an angle of < 75° and > 15° to longitudinal sides of this product surface.
4. Mineral fibre product according to claim 1, the fibres of which that are oriented substantially parallel to a product surface run predominantly at an angle of < 70° and > 20° to longitudinal sides of this product surface.
5. Mineral fibre product according to claim 1, wherein the fibres oriented substantially parallel to a product surface have a predominantly opposed orientation along adjacent strip-shaped zones.
6. Mineral fibre product according to claim 1 comprising several layers of primary nonwoven arranged one on top of the other, wherein adjacent fibres of adjacent primary nonwoven layers have a predominantly opposed orientation.
7. Mineral fibre product according to claim 5, wherein adjacent fibres of adjacent primary nonwoven layers intersect.
8. Mineral fibre product according to claim 5 with a thermal conductivity of < 0.04 W/mK parallel to the primary nonwoven layers.
9. Mineral fibre product according to claim 5 with a thermal conductivity of < 0.038 W/mK parallel to the primary nonwoven layers.
10. Mineral fibre product according to claim 5 with a compressive strength of ≥ 150 kPa respectively perpendicular to narrow sides of the product.
11. Mineral fibre product according to claim 5 with compressive strengths perpendicular to narrow sides of the product that differ by less than +/- 15% from a mean value.

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