WO1999050042A1

WO1999050042A1 - Method and apparatus for the continuous production of panels made predominantly of elastomer

Info

Publication number: WO1999050042A1
Application number: PCT/EP1999/002130
Authority: WO
Inventors: Alberto Giordani
Original assignee: TECNOGOMMA Srl
Current assignee: TECNOGOMMA Srl
Priority date: 1998-03-30
Filing date: 1999-03-29
Publication date: 1999-10-07
Anticipated expiration: 2000-09-30
Also published as: ITVI980065A1; AU3418299A

Abstract

A method and an apparatus for the continuous production of panels made of predominantly elastomeric aggregate, which includes: devices (2) for mixing the components (3) and for adding binders and catalysts to the components; a means (16, 17) for edge trimming an aggregated layer (15) of the components and a means (18) for cropping it, so as to form the panels (19); a means (6) for leveling the components in a disaggregated layer (7); a means (9) for pressing and heating the layer which simultaneously applies thereto an advancement motion which is uniform through its thickness; the devices and means are driven by at least one control and management unit.

Description

METHOD AND APPARATUS FOR THE CONTINUOUS PRODUCTION OF PANELS MADE PREDOMINANTLY OF ELASTOMER

The present invention relates to a method and an apparatus for the continuous production of panels made of predominantly elastomeric aggregate, particularly useful in the recycling of residues and waste of the rubber industry.

A wide variety of panels produced with the above waste is commercially available; these panels are suitable to meet the most disparate requirements in terms of construction, heat insulation and soundproofing and can be divided into two main categories: rectangular panels with sides having comparable dimensions; — longitudinally highly elongated panels.

In the first case, the production process includes the following steps:

— mixing the rubber waste and residues with binders of the isocyanate, urea or other types and with catalysts; — pressing at the temperature of approximately 80°C for the time required by the mixture to cross-link;

— optional trimming and/or rabbeting the edges if molding has not been performed in preforming molds.

In the second case, the process considerably differs from the preceding one, especially in the post-mixing part, in fact the last operations are:

— pressing the mixture within large cylindrical preforming molds at a suitable temperature for a time necessary for its cross-linking; — laminating the cylinder on veneer cutting machines, so as to obtain a mat having a preset length and thickness.

The discontinuous production that is typical of these processes is by far their most important drawback. Both in the first case and in the second case, the above listed steps in fact require the availability of a significant number of machines which perform the above mentioned operations in succession. This entails the need to set the treatment times of each individual machine to a same value in an attempt to reduce the associated production costs. This need, however, is limited by the low automation that can be applied to these kinds of system, which is mainly restricted to operations for transfer from one machine to another which can be performed by virtue of lift trucks and the like.

This drawback combines with a poor production yield despite a significant technological investment. Especially in the production of longitudinally highly elongated panels, veneer cutting machines, due to obvious inherent technological limitations, produce a panel which can be rendered flat in an optimum manner up to a certain radius of the cylinder. The remaining portion is then reground and returned to the production cycle, causing a significant increase in transformation costs.

In addition to the above, in both cases it is necessary to mention the high transport costs required for large supplies because a transportable apparatus cannot be available at the installation site. The aim of the present invention is to eliminate the above cited drawbacks of the prior art. An object of the invention is to provide a method and an apparatus for the continuous production of panels made of predominantly elastomeric aggregate which allow to reduce the times, and accordingly the costs, for the production of the panels, furthermore allowing high production yields with great economies of scale.

A further object of the invention is to provide a method and an apparatus which allow to perform simultaneously steps which are sequential in conventional processes.

A further object is to provide a method and an apparatus which can be automated to a high degree and can be managed relatively easily by virtue of control and management interfaces .

A further object is to provide an apparatus which performs the method by using machines which are at least partly already known and commercially available at advantageous prices.

Still a further object of the invention is to provide a method and an apparatus which can also be used in the recycling of residues from other production fields, such as for example waste paper, cork chips, fabric cuttings, leather waste, polyurethanes and inert waste materials in general. This aim, these objects and others which will become apparent hereinafter are achieved by a method for the continuous production of panels made of predominantly elastomeric aggregate, including an initial step for mixing the components of the panels and for adding binders and catalysts to the components, and final steps for edge trimming and cutting so as to form the panels, characterized in that it includes the intermediate steps of: — preparing a disaggregated layer of the components; — pressing and heating the layer during a continuous advancement thereof for the time required by the components to cross-link into an aggregated layer.

The above aim and objects and others which will become apparent hereinafter are also achieved by an apparatus for the continuous production of panels made of predominantly elastomeric aggregate, which includes devices for mixing the components and for adding the binders and the catalysts to the components, a means for edge trimming and cropping an aggregated layer of the components so as to form the panels, characterized in that it includes a means for leveling the components in a disaggregated layer, a means for pressing and heating the layer and for simultaneously applying an advancement motion thereto which is uniform through the thickness of the layer, the devices and the means being driven by at least one control and management unit.

Further characteristics and advantages will become apparent from the description of a preferred but not exclusive embodiment of the method and of the apparatus, illustrated 5

only by way of non-limitative example in the accompanying drawing, wherein:

FIG. 1 is a partially sectional general side view of the apparatus according to the invention;

FIG. 2 is a detail perspective view of the pressing and heating means ;

FIG. 3 is a front view of the edge trimming action.

The method according to the invention includes an initial step of mixing the components of the panels, which are predominantly constituted by fragments, granules and shavings of rubber, granules of cork or of other material.

This mixture receives the addition, during the mixing step or separately, of chemical binders such as isocyanate or urea compounds and catalysts which must promote and accelerate, at adapted temperature and pressure conditions, the cross-linking of the components. Then a horizontal disaggregated layer of these components, levelled in an upward region, is prepared continuously. This layer is subjected to uniform, continuous and combined compressions in order to reduce its thickness to the final dimensions, and to heating in order to create the conditions suitable for producing chemical bonds, mediated by the binders, among the components. These actions are performed during a continuous advancement of the entire layer. Once pressing and heating have been completed, the layer is in a fully 6

aggregated state with physical and mechanical propesties, such as thickness, density, dynamic modulus of elasticity et cetera which are uniformly distributed and constant. After the above described operations, the resulting layer is immediately subjected to trimming on the sides that lie parallel to the advancement direction and then cropped at preset intervals to obtain the finished panels.

With reference to the figures, the apparatus, according to the invention generally designated by the reference numeral 1, includes a mixer 2 in which the components 3 are mixed together with the binders and with the catalysts, metered according to the amounts to be mixed, which are in turn supplied by an additive feeder (not shown). The components 3 thus mixed are discharged continuously onto lower members 4 of an underlying conveyor 5. Each member is formed by a core with a horizontal base and with two vertical lateral walls in the direction of advancement of the underlying conveyor 5. These members cause the advancement of the material below a leveling device 6, which is suitable to distribute the components in a disaggregated horizontal layer 7 which is leveled in an upward region. The leveling device 6 is constituted by rotating or oscillating devices which can be of a per se known type. This particular case shows a cylinder which is provided with paddles on its surface and rotates so as to repel the excess material. In any case, the leveling device 6 is vertically adjustable in order to vary the thickness of the incoming components 3. In this way, by varying the input amounts, it is possible to vary the final density of the panels 19. The layer thus arranged within the lower members 4 is drawn into a horizontal containment and pressing chamber 8 of a pressing and heating means 9 which is constituted by a strong structure which supports the underlying conveyor 5 and an overlying conveyor 10, which are arranged mutually opposite and parallel along an extent which constitutes the longitudinal dimension of the chamber 8. The chamber 8 is formed, in a lower region, by the same lower members 4 and, in an upper region, by upper members 11 which form the overlying conveyor 10 and are constituted by horizontal plates, each of which fits between the lateral walls of the corresponding lower member 4. In order to ensure that the layer 12 being aggregated advances uniformly within the presser means 9, the conveyors 5 and 10 have, in the portions that constitute the chamber 8 , an advancement motion whose direction and orientation are the same and whose speeds are equal in absolute value. The heating of the layer 12 being aggregated occurs by contact between its surfaces and the lower members 4 and the upper members 11, which in turn are heated to approximately 90°C by irradiation of infrared rays originating from sources 13 located in the vicinity of the conveyors 5 and 10.

The two conveyors 5 and 10 can also be moved mutually closer, for example by means of a screws and bevel gear pairs assembly (not shown), in order to adjust the distance between the base core of the lower members 4 and the plates of the upper members 11, so as to be able to produce panels 19 having variable thicknesses and densities with the same presser means 9. At the facing portions of the conveyors 5 and 10 there are metal profiles 14 which lie inside the conveyors in order to prevent excessive deformations of the containment and pressing chamber 8 when subjected to stress. At the end of the continuous pressing and heating operations, the layer is uniformly aggregated 15; by using the advancement applied to it by the conveyors 5 and 10, it is placed between an edge trimming means, 16, 17, which is constituted by four rotating circular blades which are arranged in pairs along the advancement direction of the aggregated layer 15. In this embodiment, the blades are arranged at right angles, so as to cut a step into the longitudinal edges of the aggregated layer 15. Finally, a cropping means 18, such as a rotating circular blade like the preceding ones, acts to cut the layer on the fly at preset intervals at right angles to the advancement direction of the aggregated layer 15, thus providing the finished panel 19. The apparatus 1 also includes two devices 20 for unwinding a flat support 21, made for example of bituminized feltpaper, fabric or non-stick material. These devices are arranged respectively in front of the underlying conveyor 5 and above the overlying conveyor 10 and continuously supply to the members 4, 11 of the respective conveyors 5, 10 the substrate on which the aggregating layer 12 anchors itself during pressing and heating. The substrate is used to prevent the aggregating layer 12 from bonding with the surfaces of the members 4, 11, compromising the quality of the finished panels 19. In view of the numerous parameters on which it is necessary to act in order to set up the apparatus 1 , the apparatus is provided with a control interface (not shown). With reference to the above figures, operation is as follows.

The components 3 are mixed with binders and catalysts and are then deposited haphazardly and continuously on the lower members 4 of the underlying conveyor 5 to carry them below the leveling device 6 which distributes them into the disaggregated horizontal layer 7 which is leveled in an upward region. This layer is sent into the heated containment and pressing chamber 8 of the presser means 9 in which the combined action of the upper members 11 of the overlying conveyor 10 and of the lower members 4 of the underlying conveyor 5, by suitably compressing and heating the aggregating layer 12, facilitate the complete cross- linking of its components 3 whilst it advances toward the unloading region. The layer 15 thus aggregated is then subjected to longitudinal and transverse cutting operations to produce the finished panel 19.

It has been found in practice that the invention achieves the intended aim and objects, the apparatus being capable of producing approximately 200 m²/h of panels against the 60 m²/h which can be produced with prior art systems.

The apparatus and the method according to the invention are susceptible of numerous modifications and variations, within the scope of the appended claims.

The materials used, as well as the contingent shapes and dimensions, may of course be any according to the 10

requirements and the state of the art,

Claims

11CLAIMS

1. A method for the continuous production of panels made of predominantly elastomeric aggregate, comprising an initial step of mixing the components of said panels and of adding binders and catalysts to said components, and final steps for edge trimming and cutting so as to form said panels, characterized in that it comprises the intermediate steps of: ΓÇö preparing a disaggregated layer of said components; ΓÇö pressing and heating said layer during a continuous advancement thereof for the time required by said components to cross-link into an aggregated layer.

2. A method according to claim 1, characterized in that said pressing and said heating are uniform and continuous on said aggregating layer.

3. A method according to claim 2, characterized in that the parameters for the heating, pressing and continuous advancement of said aggregating layer allow the complete cross-linking of said components, mediated by said binders and catalysts, so as to form said aggregated layer.

4. An apparatus for the continuous production of panels made of predominantly elastomeric aggregate, comprising devices for mixing said components and for adding said binders and said catalysts to said components, a means for edge trimming and a means for cropping an aggregated layer of said components so as to form said panels, characterized in that it comprises a means for leveling said components in a 12

disaggregated layer and a means for pressing and heating said layer which simultaneously applies thereto an advancement motion which is uniform through the thickness of said layer.

5. An apparatus according to claim 4, characterized in that said leveling means comprises rotating or oscillating devices which can be adjusted vertically and arrange said components in said horizontal and leveled disaggregated layer.

6. An apparatus according to claim 4, characterized in that said pressing and heating means comprises a pair of conveyors, an underlying one and an overlying one, with at least two mutually facing parallel portions which are respectively constituted by lower and upper members which mate so as to form, in said portions, a horizontal chamber for containing and pressing said disaggregated layer, said members being moved, over at least said portions, at a speed whose orientation and direction are the same and which is equal in absolute value.

7. An apparatus according to claim 6, characterized in that each one of said lower members is formed by a core with a horizontal base and with lateral vertical walls in the direction of advancement of said layer, and in that said upper members are constituted by plates which can be accommodated within said walls so as to close said lower members in an upward region. 13

8. An apparatus according to claim 7, characterized in that the gap between said plates of said upper members and said base cores of said lower members is adjustable.

9. An apparatus according to one or more of the preceding claims, characterized in that it comprises profiles which are arranged close to said portions of said conveyors and are suitable to limit the stress deformation thereof.

10. An apparatus according to one or more of the preceding claims, characterized in that the facing surfaces of said lower members and of said upper members are provided with raised portions to be applied to the surfaces of said aggregating layer.

11. An apparatus according to claim 4, characterized in that the heating of said layer of said components being aggregated occurs by contact with the internal surfaces of said upper and lower members of said conveyors.

12. An apparatus according to claim 11, characterized in that the heating of said upper and lower members occurs by irradiation, with infrared rays originating from sources located proximate to said portions of said conveyors.

13. An apparatus according to claim 4, characterized in that said edge trimming means comprises a pair of rotating circular blades, arranged in the advancement direction, for each side of said aggregated layer, in order to produce edge trimmings in a substantially vertical direction and in a 14

substantially horizontal direction.

14. An apparatus according to claim 4, characterized in that said cropping means is at least one rotating circular blade arranged at right angles to the advancement direction in order to perform said croppings of said aggregated layer at preset intervals.

15. An apparatus according to one or more of the preceding claims, characterized in that it comprises a pair of devices for unwinding flat substrates onto which said aggregating layer is to be anchored whilst hot, one device being arranged in front of said underlying conveyor and the other one being arranged in front of and above said overlying conveyor, to which they feed said substrates.