EP2480387A1

EP2480387A1 - Method for producing cardboard panels or cardboard-panel strands from waste paper

Info

Publication number: EP2480387A1
Application number: EP10755189A
Authority: EP
Inventors: Michael SCHÖLER
Original assignee: Siempelkamp Maschinen und Anlagenbau GmbH and Co KG
Current assignee: Siempelkamp Maschinen und Anlagenbau GmbH and Co KG
Priority date: 2009-09-23
Filing date: 2010-09-23
Publication date: 2012-08-01
Also published as: DE102009042362A1; CN102712097A; WO2011036201A1

Abstract

The invention relates to a method for producing cardboard panels or cardboard-panel strands from waste paper, wherein waste paper is comminuted into waste-paper fibres, wherein the waste-paper fibres are glued using a bonding agent, wherein a fibre mat is produced from the glued waste-paper fibres, and wherein the fibre mat is compressed in a continuous press, using pressure and heat, to form a cardboard panel or a cardboard-panel strand.

Description

Description:

The invention relates to a method for the production of cardboard plates or cardboard board strands or cardboard webs from waste paper.

The production of cardboard takes place in practice similar to the production of paper. From wood raw materials cellulose or pulp is first obtained, which is broken down into its fibers and ground to an aqueous pulp. In this context, waste paper is recycled, which, however, is usually added only to a certain extent. The pulp made of aqueous pulp is applied to a sieve-like endless belt and processed into cardboard or cardboard. A disadvantage is the enormous use of water in the known manufacturing process, because the applied to the screen belt slurry consists to a considerable extent of water. This causes enormous costs and is also environmentally disadvantageous. This applies equally to the production of paper on the basis of wood-based materials as well as for the production of cardboard or cardboard from waste paper.

In the production of wood-based panels, it is known to glue wood fibers with a binder and to press in a continuous press to a wood-based panel. It can be worked in the rule without the addition of water. The developments known from the wood-based panel industry have so far had no influence on the production of cardboard.

The invention has for its object to provide a method which allows a cost-effective and economical production of cardboard plates or board slivers of waste paper.

To solve this problem, the invention teaches a method for the production of cardboard or cardboard board strands from waste paper, waste paper is shredded to waste paper fibers, the waste paper fibers are glued with a binder, wherein from the glued recycled paper fibers, a fiber mat is produced and wherein the fiber mat in a continuous press is pressed using pressure and heat to a cardboard plate or a cardboard board strand. Particularly preferably, the waste paper is crushed without the use of water to the waste paper fibers, z. B. in one or more mills. In this case, one or more hammer mills and / or Siebkorbmühlen can be used. The invention is based on the recognition that cardboard plates or board strands can be produced economically, inexpensively and environmentally friendly from waste paper, if dispensed with the conventional treatment of waste paper with water. Instead, the waste paper fibers are glued with a binder, similar to what is known from wood-based panel production. As a binder can z. B. the known from MDF manufacturing resins are used, for. As urea resins, melamine resins, phenolic resins. Alternatively, isocyanates can be used. Optionally, recourse is made to binders consisting of paper and paper

Cardboard production are generally known as sizing agents, for. B. resin glues and usually ready for use rosin size dispersions such. As alkyl ketene dimer dispersions (AKD) or alkenyl succinic anhydride (ASA) or polymer sesions of styrene acrylic acid or styrene maleic acid or polyurethane dispersions or starch, dextrins, polyamines or acrylates. Overall, can be in the invention fibers, which are obtained by mechanical treatment of waste paper, in a simple and cost-effective manner environmentally friendly to cardboard boards or cardboard board strands press.

Preferably, the fibers obtained from waste paper to fiberboard or fiberboard strands with a thickness of up to 3 mm, preferably 0.1 mm to 3 mm, z. B. 0.1 mm to 1, 5 mm pressed. The weight per unit area of the cardboard plates or cardboard slabs is preferably 0.1 kg / m ² to 3 kg / m ² , z. B. 0.1 kg / m ² to 1, 5 kg / m ² .

The gluing of the fibers can take place during the pneumatic transport. The fibers are pneumatically z. B. transported by a conveyor line and in the course of transport in the delivery line glue is added by spray nozzles. In a modification, it is possible to glue the waste paper fibers in a (vertical) chute. - Again, the fiber feed takes place pneumatically via a fiber feed line. A fiber outlet tube opens in the upper area in a vertically arranged chute. In the upper region of this chute or above the chute, a plurality of spray nozzles for the gluing of emerging from the fiber outlet tube and entering the chute fibers are arranged. In this case, between the fiber outlet tube and the chute in a Beleimungszone the gluing device

be provided a plurality of spray nozzles. The chute may be arranged downstream of a collecting device for collecting and discharging the glued fibers. This collecting device may have an air-permeable conveyor belt for collecting and discharging the fibers and a suction device arranged below the conveyor belt for sucking air out of the chute through the conveyor belt. This conveyor belt is designed as a sieve belt or filter belt. Consequently, the fibers emerging from the fiber outlet tube and subsequently glued pass over the chute onto the conveyor belt. On the conveyor belt, the glued fibers come to rest. Optionally sinking in the chute unused glue reaches the arranged on the conveyor belt fibers, so that a complete Leimausnutzung is guaranteed. Such chute-gluing is for wood fibers z. B. from DE 10 2006 058 625 B3, DE 10 2006 058 626 B3 and DE 10 2006 058 627 B3.

Optionally, the fibers may be glued in a continuous mixer having at least one mixing chamber and one or more mixing tools mounted on a rotating mixer shaft, the mixing tools mixing the fibers with the binder and conveying them through the mixing chamber in a conveying direction. Such mixing devices are also referred to as gluing mixers. The mixing chamber is generally cylindrical in shape as a drum, but this drum does not rotate, but is usually fixed. The mixing chamber has at least one loading opening for the fibers and at least one discharge opening for the fiber-binder mixture and a plurality of binder feed openings for the supply of the binder. The binder feed can take place via the mixing tools themselves, in which case a hollow shaft is usually used.

formed mixer shaft is provided. Optionally, the binder supply but also via in the interior of the mixing chamber projecting feed pipes.

Tests have shown that paperboard plates with particularly good properties can be produced in the desired thickness if the fiber mat, which is subsequently pressed into a plate, is produced on a spreading belt conveyor by means of a strainer. Such a strainer is already known for MDF production (see WO 03/053642 A1) The invention has now recognized that such a strainer can be used excellently in the course of paperboard production Preferably, the scattering head has a plurality of rows arranged one after the other in the conveying direction or in the running direction of the scattering belt conveyor, each having a plurality of transversely to the conveying direction or running direction of the scattering belt conveyor The stirring elements of one row can rotate in the same direction, while the stirring elements of respectively adjacent rows preferably rotate in the opposite direction The distance between two adjacent stirring elements of a row can be approximately equal to the stirring width of the stirring elements speak and each two adjacent rows can be arranged offset by a predetermined amount transversely to the conveying direction or strip running direction to each other. Of particular importance is in such a Siebstreukopf the fact that on the opposite side of the screen bottom surface of the scatter belt conveyor at least one suction box is arranged. Preferably, a plurality of suction boxes may be provided. In any case, can be produced with such a Siebstreukopf fiber mats high quality, from which

Press cardboard boards of high quality. Foreign bodies can be sorted out particularly advantageously with such a strainer. Overall, a very homogeneous fiber mat can be produced. The preferably used scattering head is particularly well suited to the mechanical properties of the fiberboard, such. B. tensile strength or flexural rigidity to influence. Thus, there is the possibility that the fiber mat is scattered with the proviso that the mechanical properties of the fiberboard, such as tear strength and / or flexural rigidity in the longitudinal and transverse directions are substantially equal. Optionally, it is possible to sprinkle the fiberboard with the proviso that the mechanical properties of the fiberboard, such. As tensile strength and / or bending stiffness, vary in the longitudinal and transverse directions and are therefore different, for. In a ratio of up to 2: 1, preferably up to 1.5: 1. It is therefore possible to produce by targeted scattering plates, the tensile strength and / or bending stiffness in the longitudinal direction by a factor of up to 2, preferably by a factor of up to 1, 5, z. B. by a factor of about 1, 5 is greater than in the transverse direction.

The fiber mats are pressed in a continuously operating press. It may be z. B. to act a double belt press, which has a heatable upper press plate and in the press base a heated lower press plate and in the press upper part and in the press base endlessly circulating steel press belts in the press upper part. The steel press belts are supported with the interposition of Wälzkörperaggregaten against the press plates. As a rule, hydraulic cylinder piston arrangements are provided which operate on the upper and / or lower press plate. The fiber mat can be pressed with a pressure of 15 to 50 bar and a temperature of 120 ° C to 250 ° C. Basically you can

but also continuously operating press devices of other types are used.

The board boards or board webs produced by the method according to the invention can be processed very well, in particular for packaging. The material can be excellently punched, folded, folded, creased or shaped in other ways. There are z. B. creates clean kinks, so that can produce high-quality cardboard. The production is cost-effective and therefore economical and environmentally sound because it can be used with very small amounts of water.

In the following the invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. 1 shows a schematically greatly simplified process diagram,

2 shows a preferably usable scattering head for the method according to FIG. 1 in a side view and FIG. 3 shows the object according to FIG. 2 in a plan view (detail).

In Fig. 1, the inventive method for the production of cardboard plates or cardboard board strands from waste paper is greatly simplified. The waste paper a is comminuted (mechanically) in a first process step b, ie waste paper fibers are produced from the waste paper. The processing of the waste paper to waste paper fibers takes place without the addition of water. If necessary, foreign objects, small parts or the like can be sorted out. The "dry" recovered paper fibers produced in this way are in one

Gluing device glued (Verfahrensschntt c). For this purpose, a conventional gluing during the pneumatic fiber transport, z. B. a chute gluing be provided. The glued fibers are then usually fed to a fiber bunker. From there, in a method step d, a fiber mat can be sprinkled on a scatter belt conveyor with the aid of a spreading device or a spreading head. The fiber mat made of glued fibers is optionally precompressed and then pressed in a continuously operating press to form a cardboard board or cardboard board strand (method step e). As a rule, a continuous board slab strand (i.e., a board web) exits the continuously operating press, as a rule, further processing takes place (step f). The board web or the cardboard board strand z. B. wound or cut into slices. Particularly preferably, the production of the fiber mat (method step d) is carried out with a strainer, as it is known for example from WO 03/053642 A1. Reference is made to FIGS. 2 and 3.

FIG. 2 shows the fiber bunker 2 with a dosing unit 3. Essentially, the metering unit 3 consists of a metering belt 4 and a plurality of metering and / or opening rollers 5. The waste paper fibers are fed via a bunker belt or distributor belt 6 to the bunker or the metering and / or opening rollers 5, which essentially Dissolve grit compactors. A bunker filling is arranged schematically in FIG. 1 above the dosing belt. The discharge quantity of the dosing belt bunker or the dosing unit can be varied essentially by lowering or increasing the speed of the dosing belt 4. Bunker or metering unit, however, can also be realized in another embodiment. Anyway

the spreading material from the bunker 2 or the dosing unit 3 is sprinkled on a scattering head 7 arranged above the scatter band conveyor 1. With the help of the scattering head 7, a fiber mat M is produced from glued waste paper fibers on the scatter belt conveyor 1. This is shown in particular in Fig. 2. Following the scattering head 7 is a continuous press, not shown, or a pre-press.

The scattering head 7 is designed as a strainer 7 with a sieve bottom surface 8 and a plurality of arranged at a predetermined distance above the sieve bottom surface 8 stirring elements 9 with a predetermined stirring width B. In this case, the stirring elements 9 are arranged in a housing 10, whose housing underside forms the sieve bottom surface 8 or on the underside of which the sieve bottom surface 8 is arranged. According to FIG. 3, the scattering head 7 has a plurality of rows 1 1 arranged one behind the other in the conveying direction F, each having a plurality of stirring elements 9 arranged transversely to the conveying direction F. With the conveying direction F is the direction of the scatter band conveyor 1, ie, the tape running direction meant, which may correspond to the direction of the metering belt 4 substantially. The individual stirring elements each have at least one stirring blade 13, which is rotatable about an axis 12 which is approximately perpendicular to the sieve bottom surface 8, with a predetermined stirring width B. The stirring blades 13 are z. B. each one-piece and rod-shaped with rectangular or square cross-section. Other impeller configurations are possible. The stirring vanes 13 rotate in a common plane which extends substantially parallel to the sieve bottom surface 8, directly above the sieve bottom surface 8. The stirring vanes 13 are designed as double vanes with an overall blade length corresponding to the stirring width B. By the arrows in Fig. 3 is indicated that the stirring elements 9 in a row 1 1 in

Rotate the plant in the same direction. In contrast, the stirring elements 9 each rotate adjacent row in the operation of the system in the opposite direction. The distance A of two adjacent stirring elements 9 in a row 1 1 corresponds approximately to the stirring width B of the stirring elements, wherein with the distance A of these stirring elements 9, the distance A between the axes 12 is meant. Furthermore, it can be seen in Fig. 3 that each two adjacent rows 1 1, ie z. B. the first and second row, offset by a predetermined amount V transversely to the conveying direction F are arranged to each other. This measure or the offset V of these rows corresponds approximately to half the stirring width, so that the first and third rows are again arranged in alignment with each other without offset. In this context, it is provided that the distance C of two adjacent rows 1 1 by a predetermined amount is smaller than the stirring width B. This is also indicated in Fig. 3.

In the exemplary embodiment, at least one suction box 15 is arranged on the side opposite the sieve bottom surface 8, ie below the scatter belt conveyor 1, which generates a directed from the sieve bottom surface 8 on the scatter belt conveyor 1 air flow and thus the spreading material on the scatter belt conveyor or the wire belt. 1 sucks. It is shown in FIG. 2 that a plurality of suction boxes 15 arranged below the scatter band conveyor 1 are provided. This is a plurality of in the strip running direction successively arranged suction boxes 15, each extending substantially transversely to the strip running direction. One or more suction lines can be connected to the individual suction boxes 15, wherein the suction effect of the individual suction lines or suction boxes 15 z. B. is adjustable via throttle. It is possible, the suction of the suction boxes 15 and the entire

Adjust suction arrangement over the length and / or across the width and adapt to the requirements. Finally, it can be seen in FIGS. 2 and 3 that the scattering head 7 has at its end a discharge device 16 for residual fibers or coarse material and excess material extending transversely to the conveying direction F of the scattering belt conveyor 1. This discharge device is merely indicated and formed in the embodiment as a discharge screw 16.

Incidentally, between each two adjacent stirring elements 9 in a row 1 1 and in the edge regions of the scattering head separating or side walls 17 may be arranged, which extend from row to row over substantially the entire length of the scattering head 7 and substantially in Form conveying direction extending conveying channels 18. In this case, the partitions 17 are adapted in shape to the shape and position of the stirring elements 9, so that form quasi-like or serpentine conveying channels 18 because of the staggered row arrangement in the plan view. Consequently, the spreading material in the individual conveying channels 18 is waved in the plan view, so that a particularly homogeneous spreading material distribution occurs, both in the conveying direction F and also transversely to the conveying direction F. Furthermore, it is indicated in some regions in FIG. 3 that covering segments 20 are connected to the partitions 17 in the region of the stirring surface interspaces 19, which substantially cover or fill the stirring surface interspaces 19.

The described scattering head is particularly well suited to set the mechanical properties such as tensile strength or bending stiffness in the longitudinal and transverse direction of the plate targeted.

Claims

claims:

1 . A process for the production of cardboard slabs from waste paper, wherein waste paper is comminuted to waste paper fibers, wherein the waste paper fibers are glued with a binder, wherein from the glued waste paper fibers, a fiber mat is produced and wherein the fiber mat in a continuous press using pressure and heat is pressed to a cardboard plate or a cardboard board strand.

2. The method of claim 1, wherein the waste paper is comminuted without the use of water, z. B. in a hammer mill and / or a Siebkorbmühle.

3. The method of claim 1 or 2, wherein the glued waste paper fibers in the continuous press to a fiberboard or fiberboard strand having a thickness of up to 3 mm, preferably 0.1 mm to 3 mm, z. B. 0.1 mm to 1, 5 mm are pressed.

4. The method according to any one of claims 1 to 3, wherein the waste paper fibers in the continuous press to a fiberboard or a fiberboard strand with a basis weight of 0.1 kg / m ² to 3 kg / m ² , preferably 0.1 kg / m ² be pressed to 1, 5 kg / m ² .

5. The method according to any one of claims 1 to 4, wherein the fiber mat of waste paper fibers by means of a Siebstreu head is produced on a Siebbandförderer, wherein the Siebstreukopf a Siebbodenfläche and a plurality of arranged at a predetermined distance above the Siebbodenfläche distribution elements, for. As stirring elements, wherein one or more suction boxes are preferably arranged on the opposite side of the screen bottom surface of the scatter belt conveyor.

6. The method according to any one of claims 1 to 5, wherein as binders synthetic resins, in particular urea resin, melamine resins or phenolic resins, or isocyanates are used.

7. The method according to any one of claims 1 to 5, wherein as binder alkyl ketene dimer dispersions (AKD) or alkenyl succinic anhydride (ASA) or polymer dispersions of styrene acrylic acid or styrene maleic acid or polyurethane dispersions or starch or dextrins or polyamines or acrylates are used.

8. The method according to any one of claims 1 to 7, characterized in that the waste paper fibers in the course of pneumatic transport, z. B. in one

Förderel be glued.

9. The method according to claim 8, characterized in that the fibers are glued in a vertical chute, to which the fibers are fed pneumatically and which has spray nozzles for the gluing of emerging from a fiber outlet tube and entering a chute fibers.

10. The method according to any one of claims 1 to 9, wherein the fibers are glued in a (continuous) mixer, which has at least one mixing chamber and one or more attached to a rotating mixer shaft mixing tools, wherein the mixing tools mix the fibers with the binder and in promote a conveying direction through the mixing chamber.

1 1. Method according to one of claims 1 to 10, wherein the fiber mat is scattered with the proviso that the mechanical properties of the fiberboard, such. B. tensile strength and / or bending stiffness in the longitudinal and transverse directions are substantially equal.

12. The method according to any one of claims 1 to 10, wherein the fiber mat is scattered with the proviso that the mechanical properties of the fiberboard, such. B. tensile strength and / or flexural rigidity in the longitudinal direction and in the transverse direction vary, for. B in a ratio of up to 2: 1, preferably in a ratio of up to 1, 5: 1, z. B. about 1, 3: 1 to 1, 5: 1.