EP1119662B1 - Plate which is suited as a noise protection wall - Google Patents

Abstract

A plate utilizable in a noise protection wall of fragile acrylic glass comprising a plurality of side by side synthetic monofilament plastic threads for embedded in and running along the plate for splinter binding on breakage of the glass wherein, at least one thread has a maximum deviation of 1 mm or more from a theoretical straight line connecting the ends of said thread.

Description

The invention relates to noise protection elements suitable plates from per se fragile acrylic glass, which contain embedded for fragmentation in eventual breakage of the glass monofilament plastic threads.

Plates of the type mentioned above, which are secured against the formation and falling of loose fragments are known for example from EP 0 407 852. The plates disclosed therein contain embedded, based on the plate cross section, approximately centrally monofilament plastic threads or a mesh fabric of such threads. As plastic threads monofilament threads made of polyamide are particularly well suited. In the cited EP 0 407 852 it is emphasized that the embedded plastic threads are almost invisible, so that the view through the element is preserved. In addition, due to the fact that the plastic threads are embedded in the interior of the plate, an optimal protection against weathering is given. The cleaning of the panels is completely trouble-free, above all they are secured even at low temperatures (-20 ° C) against the formation and falling of loose fragments. It should be noted, however, that the central arrangement places a very high demand on the production of such plates.

According to EP 0 826 832 shatter-proof noise protection plates made of acrylic polymers are known, which contain filaments of plastic material, wherein the filaments are not arranged centrally. Rather, the filaments are arranged at a distance of between 20 and 35% of the total thickness of the plate with respect to the surface facing away from the surface which is exposed to a possible crash. According to the said EP 0 826 832 can be surprisingly also with the non-central Arrangement shatterproof noise protection elements obtained. However, it remains to be said that the test methods used to substantiate this alleged effect are relatively insignificant, since the impact energies applied are only in an insufficiently high range. In contrast, an element according to EP 0 407 852 easily passes a test based on DIN 52 290, ie a corresponding plate that rests freely on two sides, is indeed on impact of falling from 9 m height steel ball with a mass of 4.1 kg Smashed, but there are no free fragments. In particular, all fragments formed are held together by the embedded threads.

US-A-5 040 352 discloses in Example 2 an acrylic sheet with an embedded "mesh fabric" of monofilaments with a diameter of 1.2 mm.

According to the invention, it has now unexpectedly and surprisingly been found that it is possible to simultaneously obtain breakage and noise protection with the aid of plates of the type mentioned above, wherein at least one of the embedded threads has a maximum deflection of 3 mm or more from an imaginary one through the ends of this thread straight line.

This somewhat "sagging" positioning of the plastic threads in the acrylic glass matrix leads under certain circumstances to a more advantageous behavior of the invention as a noise barrier wall according to the invention in the relevant tests, such as. In accordance with ZTV-LSW 88 under 3.4.2. and the guideline LS3 of the Federal Minister of Transport: "Additional technical regulations and guidelines for the execution of noise barriers on roads". With maximum deflection is meant for the purposes of the invention, the largest distance of the thread from an imaginary line, which results between the two ends of the respective thread. Furthermore, it is even more preferable if the maximum deflection in a plate according to the invention is 5 mm or more.

The maximum deflection must not lead to the fact that the thread comes to rest outside the plate, but in the context of the invention always ensures that the plastic threads are actually embedded. The maximum deflection, or simply referred to as deflection of the plastic thread, can therefore according to the invention not be greater than the plate thickness reduced by the thread thickness, d. H. the diameter of the thread.

The deflection of the plastic thread according to the invention may in one embodiment be substantially perpendicular to the plane of the plate. Such a design of the embedded threads can be achieved, for example, by embedding the threads in an acrylic molding compound for casting purposes under the influence of gravity according to a horizontal chamber method.

As an alternative to this embodiment, it may also be preferred that the deflection of the plastic threads is substantially parallel to the plane of the plate. Such a configuration of the thread arrangement results, for example, informally in that the plates are cast according to the so-called Rostero method. In vertical chambers, as is usual according to this method, bend or hang the threads under the influence of gravity parallel to the plane of the plate.

Yet another expedient embodiment of the plates according to the invention provides that the plate contains threads whose deflection is substantially perpendicular to the plane of the plate, and that the plate contains threads whose deflection is substantially parallel to the plane of the plate. Such an arrangement of the securing threads is obtainable, for example, by using two threads of different lengths and therefore the one thread almost parallel to the glass surface, or the other thread has a deflection perpendicular to the plate plane.
Also, two 15 mm plates, each with a vertical or parallel deflection to the glass surface stick together to form a 30 mm thick plate, and thus a plate according to the invention is obtained.
A special case consists of a rolled embedded polyamide thread, this has a particularly favorable fracture behavior. It makes sense to use a transparent polyamide thread here, otherwise the transparency of the plate is greatly reduced.

Depending on the procedure and production of the plates according to the invention, therefore, an almost arbitrary orientation of the plastic filaments in the polymer matrix is possible. Thus, in addition to a vertical or parallel arrangement to the plane of the plate, a deflection can also be achieved, which in arbitrary gradation lies arbitrarily between these limit values.

According to the invention, the threads may run substantially parallel to one of the surfaces of the plate.

In addition, the invention also makes it possible to embed threads in the polymer matrix which do not run parallel to a surface, but which are, for example, embedded transversely.

This means that with regard to the first variant, in a particularly favorable embodiment, the thread ends of at least one thread have substantially the same distance to a surface in the plane of the plate and / or to one of the edges of the plate. If the aforementioned condition is fulfilled, the threads are embedded substantially parallel to a surface in the plane of the plate and / or to one of the edges of the plate.

Alternatively, with regard to the second variant, embodiments may also be preferred in which the distance of the thread ends of at least one thread to a surface in the plane of the plate and / or to one of the edges of the plate is different. Precisely from the latter circumstance follows that the production of the noise protection elements according to the invention in comparison with the production of the elements according to the prior art has been significantly simplified, because much larger tolerances can be accepted, indeed may be desirable, without thereby suffer disadvantages in the fracture properties have to.

Generally speaking, the embedded plastic filaments may be arranged to extend parallel to each other in only one direction, or to be parallel to each other in two or more directions. Here it is in the latter case ü. a. possible that the two directions form an angle of 90 ° or even an angle deviating from 90 °.

Monofilament threads of polyamide or polypropylene are particularly well suited as plastic threads, in particular because their adhesion to the surrounding acrylic glass is relatively low and thus there is no appreciable loss of tensile strength at any low temperatures. When breaking the acrylic glass, the monofilament plastic threads can stretch and tear as a result, or at best to a small extent and thereby hold the resulting fragments together. The diameter of the monofilament threads is suitably between 0.2 and 2.0 mm. The lateral distance between adjacent threads may be in the range between 8 and 100 mm. However, smaller and larger distances are also feasible.

In addition, at least parts of a thread or all threads can be dyed in high contrast. This example, black coloring can be used to design the Noise protection elements serve, on the other hand, the elements on the other hand can be protected from birds.

Plates according to the invention are made of acrylic glass and are made of materials known to those skilled in the art. Thus, the plates may preferably be cast from methyl methacrylate syrup. The size of the plates varies in the range of about 1 mx 2 m to 2 mx 3 m or even larger.
The thickness of the plates is approximately in the range of 5-30 mm, preferably 12-25 mm, in particular 15-20 mm.

The plates according to the invention are distinguished by a whole series of particularly advantageous properties:

The plates according to the invention have very good splinter-bonding properties, in particular at higher destruction rates or low temperatures. Particularly advantageous is an offset arrangement of the thread ends or a double-layered arrangement of the polyamide threads or a net-like sagging arrangement of the securing threads.

The plates thus described are outstandingly suitable for use as noise protection plates, in the railway or trans-rapid area, since particularly high destruction rates can occur here. Another advantage of the plates according to the invention consists in one-sided clamping, so show the strongly sagging two layers or sagging networks excellent cohesion in contrast to the center-centered, parallel to the surface positioned polyamide thread board.

The invention will be explained in more detail by means of embodiments with reference to the accompanying figures.

Fig. 1

einen Querschnitt durch ein Lärmschutzelement mit einer ersten erfindungsgemäßen Fadenanordnung;

Fig. 2

einen Querschnitt durch ein Lärmschutzelement mit einer zweiten erfindungsgemäßen Fadenanordnung;

Fig. 3

einen Querschnitt durch ein Lärmschutzelement mit einer dritten erfindungsgemäßen Fadenanordnung;

Fig. 4a, b

einen Querschnitt durch ein Lärmschutzelement mit einer vierten erfindungsgemäßen Fadenanordnung sowie einen Schnitt aus 4a;

Fig. 5a, b

einen Querschnitt durch ein Lärmschutzelement mit einer fünften erfindungsgemäßen Fadenanordnung sowie einen Schnitt aus 5a;

Fig. 6a, b

einen Querschnitt durch ein Lärmschutzelement mit einer sechsten erfindungsgemäßen Fadenanordnung sowie einen Schnitt aus 6a;

Fig. 7

einen Querschnitt durch ein Lärmschutzelement mit einer siebten erfindungsgemäßen Fadenanordnung;

Fig. 8

einen Querschnitt durch ein Lärmschutzelement mit einer achten erfindungsgemäßen Fadenanordnung;

Fig. 9

einen Querschnitt durch ein Lärmschutzelement mit einer neunten erfindungsgemäßen Fadenanordnung; und

Fig. 10

in perspektivischer Aufsicht eine nach dem Rosteroprozess hergestellte Platte mit senkrecht zur Plattenebene ausgelenkten eingebetteten Kunststofffäden.

In the figures show

Fig. 1

a cross section through a noise protection element with a first thread assembly according to the invention;

Fig. 2

a cross section through a noise protection element with a second thread assembly according to the invention;

Fig. 3

a cross section through a noise protection element with a third thread assembly according to the invention;

Fig. 4a, b

a cross section through a noise protection element with a fourth thread arrangement according to the invention and a section of 4a;

Fig. 5a, b

a cross section through a noise protection element with a fifth thread arrangement according to the invention and a section of 5a;

Fig. 6a, b

a cross section through a noise protection element with a sixth thread assembly according to the invention and a section of 6a;

Fig. 7

a cross section through a noise protection element with a seventh thread assembly according to the invention;

Fig. 8

a cross section through a noise protection element with a eighth thread assembly according to the invention;

Fig. 9

a cross section through a noise protection element with a ninth thread assembly according to the invention; and

Fig. 10

in a perspective plan view of a prepared by the Rosteroprocess plate with deflected perpendicular to the plate plane embedded plastic threads.

In Fig. 1, reference numeral 1 denotes a sheet of acrylic glass with embedded plastic threads. Reference numeral 2 denotes the polymer matrix, while reference numeral 3 designates a polyamide thread. 4 and 4 'mark thread beginning and end. The distance from the thread beginning and end of the thread to the surface 5 is the same, as well as the distance from the thread beginning and end of the thread to the surface 6. It can be seen that the thread 3 halfway between the thread beginning 4 and thread end 4 'a maximum deflection, d. H. Deviation from the imaginary connecting line, d. H. the straight line between 4 and 4 ', has.

FIG. 2 shows a further embodiment according to the invention, which also shows an identical distance of 4 and 4 'to the surface 5 or to the surface 6, but the distances to the two surfaces 5 and 6 are different from one another. D. h., The thread shown is not centered, so not symmetrical, but the thread shown is embedded asymmetrically.

The embodiment shown in FIG. 3 is a thread "slanted" embedded in a polymer matrix. Here, in particular, the feature is met that the distance between the thread ends 4 and 4 'of a thread to one and the same surface in the plate plane (surfaces 5 or 6) is different.

A further embodiment of the thread arrangements according to the invention is evidenced by FIG. These are two visible embedded threads 3 and 3 ', which are arranged alternately. That is, that one Thread 3 'is more "sagging" or "deflected" than the other thread 3 shown visibly. It is understood that the two threads 3 and 3' shown may be representative of a number of threads in the plate. In addition, it is clear that one of the threads can be embedded in about without significant deflection or without significant sagging, while the second illustrated thread (reference numeral 3 ') is relatively strongly deflected from the normal position. In Figure 4b, the position of the threads 3 and 3 'is explained in more detail by a section of Figure 4a.

Yet another variant of the noise protection elements according to the invention is shown in FIG. 5. This is a multilayer arrangement of threads one above the other. These can be arranged directly one above the other hanging through, but there are also embodiments with multi-layered yarns belonging to the invention.

As in the preceding FIGS. 4a, b and 5a, b, FIG. 6 also shows a further embodiment of the inventive arrangement of plastic threads, not only in cross section but also in plan view. Figures 6a, b illustrate that a net-like arrangement of sagging threads is also possible.

FIG. 7 illustrates in cross-section in a further embodiment the maximum deflection of a thread. This is a maximum of the plate thickness reduced by the thread thickness.

Another embodiment is shown in Figure 8. Here, an embodiment is shown in cross section, in which the deflection varies from thread to thread. For example, with a plate thickness of about 20 mm, the maximum deflection increases from 1 mm for the most tensioned thread up to 19 mm for the thread with the maximum deflection.

Finally, according to FIG. 9, an embodiment which is possible within the scope of the invention is clarified. In cross section, a wavy arrangement of the thread can be seen.

Finally, FIG. 10 illustrates an embodiment in which the arrangement of the embedded plastic threads is such that they have a sag or maximum deflection which runs parallel to the plate plane. As already indicated, such an arrangement of the threads is readily available, for example, in the roster process.

The following examples prove the advantageous properties of the noise protection elements according to the invention.

Example 1:

To produce an acrylic sheet according to FIG. 1, a chamber was formed from two sheets of polished silicate glass, 2 × 3 m in size, with the aid of a 20 mm circumferential seal. In this chamber were clamped parallel to each other monofilament polyamide threads with a diameter of 2 mm at a distance of 30 mm. The polyamide thread length was dimensioned such that a 5 mm polyamide thread sagging was achieved. Thereafter, methyl methacrylate syrup containing a radical-forming initiator was charged into the chamber. The filled chamber was placed in a water bath and the syrup was cured by supplying heat to a sheet of high molecular weight polymethylmethacrylate. The chamber was polymerized lying, so that the deflection of the threads was perpendicular to the PMMA surface. After demoulding, this resulted in an approximately 2 x 3 m, 20 mm thick cast acrylic sheet with embedded polyamide filaments. The positioning of the polyamide threads or the thread suspension was using a Ultrasonic echo sounder (10 megahertz measuring frequency) measured, the measuring head of the echosounder is equipped with a transmitter and a receiver, so as to measure the distance between PMMA surface and polyamide thread. In the middle of the plate a maximum sag of 4 mm was measured.

The plate thus obtained was subjected to a pendulum test. In principle, to carry out this test, a steel bulb of 400 kg is raised to 1.6 meters, destroying the plate. The evaluation criterion is the occurrence of free fragments which are not larger than 25 cm ² and have an angle of <15 °.

Execution of the pendulum test:

The 2 x 3 m large slabs are installed on three sides in a steel frame construction. At each corner of the plate there is a hole at a distance of 15 cm, which serves as a safety catch, d. h., a steel cable is used which is pulled through the four holes of the acrylic sheet and attached to the frame construction. This structure corresponds to the normal installation of a transparent noise barrier. The distance from the acrylic glass plate to the energy dissipation wall is 1.24 m. Normally, the pear smashes the acrylic sheet and is then braked by this wooden wall.

The acrylic glass pane was destroyed with the "pear", which hits the plate from a height of 1.6 m. The pear consists of two butt welded ball stumps. The impact speed was 5.6 m per second, the energy 6.278 Joule. The measurement was carried out both at 20 ° C and at -20 ° C; in both cases no free fragments appeared. For the fractional result it is irrelevant whether the thread deflection is in the direction of the destruction body or turned away from him.

Example 2 for producing a composite element:

According to FIG. 10, a chamber with 20 mm thick piping was built in the Rostero oven. Polyamide cords were inserted into this chamber at a distance of 30 mm, which had a deflection of 5 mm parallel to the surface. The diameter of the polyamide cords used was 2 mm. This chamber thus prepared was filled with a radical-forming initiator-containing methyl methacrylate syrup. After filling, the chamber was evacuated and the polymerization started by heating to 50 ° C. Due to the vertical arrangement of the polymerization chamber, the polyamide cords hung parallel to the surface. After complete curing of the plate, this was removed from the mold and subjected to a fracture test. Both at -20 ° C and at +20 ° C, no free fragments were obtained.

Example 3:

The procedure was as in Example 1, but with the difference that instead of the monofilament polyamide threads a polyamide mesh of monofilament threads with a diameter of 2 mm and a mesh size of 50 x 50 mm with a max. Suspension of 8 mm was made. This plate had a thickness of 20 mm and was subjected to the pendulum test; the difference was that the plate was not built on three sides but one-sided. In the pendulum test at 20 ° C, no free fragments appeared on this plate either.

Example 4:

The procedure was as in Example 1. The pendulum test was carried out with a height of 8 m. The impact speed was 12.53 meters per second, the energy 31,392 joules. There were no free fragments at 20 ° C. For the fractional result, it is irrelevant whether the thread deflection is turned away in the direction of the destruction body or from it.

Claims (14)

1. Sheet (1) of intrinsically frangible acrylic glass, which sheet is suitable for use as a anti-noise protection wall and which contains embedded monofilamentary plastics filaments (3, 3') to retain splinters should the glass fracture, characterised in that at least one filament (3, 3') has a maximum deflection of 3 mm or more from an imaginary straight line through the ends (4, 4') of the said filament.
2. Sheet (1) according to claim 1, characterised in that the maximum deflection is 5 mm or more
3. Sheet (1) according to one of the foregoing claims, characterised in that the deflection is substantially perpendicular to the plane of the sheet.
4. Sheet (1) according to either of claims 1 and 2, characterised in that the deflection is substantially parallel to the plane of the sheet.
5. Sheet (1) according to either of claims 1 and 2, characterised in that the sheet (1) contains filaments (3, 3') whose deflection is substantially perpendicular to the plane of the sheet, and filaments (3, 3') whose deflection is substantially parallel to the plane of the sheet.
6. Sheet (1) according to one of the foregoing claims, characterised in that the ends (4, 4') of at least one filament (3, 3') are at substantially the same distances from one and the same surface (5) in the plane of the sheet and/or from one and the same edge of the sheet.
7. Sheet (1) according to one of claims 1 to 5, characterised in that the distances of the ends (4, 4') of at least one filament (3, 3') from one and the same surface (5) in the plane of the sheet and/or from one and the same edge of the sheet are different.
8. Sheet (1) according to one of the foregoing claims, characterised in that the embedded filaments (3, 3') extend substantially parallel to one another in one direction.
9. Sheet (1) according to one of the foregoing claims 1 to 7, characterised in that the embedded filaments (3, 3') extend parallel to one another in respective ones of two directions.
10. Sheet (1) according to claim 9, characterised in that the two directions make an angle of approximately 90°.
11. Sheet (1) according to claim 9, characterised in that the two directions make an angle of other than 90°.
12. Sheet (1) according to one of the foregoing claims, characterised in that the plastics filaments (3, 3') are monofilamentary filaments of polyamide of a diameter of 0.2 to 2 mm.
13. Sheet (1) according to one of the foregoing claims, characterised in that the plastics filaments (3, 3') extend at a lateral spacing of 8 to 100 mm.
14. Sheet (1) according to one of the foregoing claims, characterised in that at least one part of a filament (3, 3') is coloured to give a high contrast, in order in this way to be used for styling the elements and/or to provide anti-bird protection.

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