DE10330756B4 - Process for producing a pulp - Google Patents

Abstract

method for producing a pulp, wherein a first group of particles and / or fibers as a second group, a proportion of plastic particles and / or fibers is mixed, for the production of moldings, in which further a binder is added and the pulp to a Molded part with the supply of heat pressed is, characterized in that the plastic particles and / or fibers by crushing and / or defibering from agglomerates Pure or mixed plastic can be obtained in a disc refiner, while the disc refiner during the crushing process water is supplied and the particle size of the plastic particles and / or fibers approximately the particle size of the particles or fibers of the first group.

Description

The The invention relates to a process for producing a pulp according to claim 1.

In the DE 103 26 181 A1 is described in the manufacture of wood-based panels, ie in particular wood chipboard and wood fiber boards, a part of the wood chips or fibers by ground or shredded agglomerate of mixed plastics from the waste to substitute. The sizes of the plastic particles on the one hand and the wood fibers or shavings on the other hand are approximately equal. In this way, a possibility of complete recycling of mixed plastics is created.

at currently existing collection systems for waste plastics, e.g. packing material from private households, yogurt cups, protective covers, shopping bags, bottles for cleaning agents, Toothpaste tubes etc. are usually obtained mixed plastics. she include in addition to the usual Films and plastics made of LDPE, HDPE or PP often leave film residues Polyamides, polycarbonates, PET or other plastics. The quantitative Quantity distribution of the various plastics used in the processing and sorting companies are handed over by collecting companies depends other of the collecting behavior and quality consciousness of the population from. Despite advanced sorting can be a complete separation the different types of plastic do not reach. A sorted separation between LDPE films of HDPE films can be with a quota of nearly Reach 95%. In addition, however, there are also collection systems exclusively for LDPE and HDPE plastics, in which predominantly Plastic films over a Foil calenders are produced, collected.

Foil or bottle fractions from collection systems are comminuted to flakes or chips after optional cleaning and presorting. In order to achieve a sufficient transport bulk density, the flakes or chips are processed in a so-called agglomeration process to a granular material. Such a method is in DE 198 01 286 C1 or AT343 445 described. The granular material is very uniform depending on the purity and grading (with high degree of purity of the plastic types) or it has a very irregular structure both of the appearance and the consistency and geometry of the agglomerate (high mixing of different types of plastic from different sources, eg Mixed plastics from household collection systems). In the processing, the mentioned agglomeration, the flakes or chips are heated by friction in a stirrer so that they melt. By spraying the heated agglomerate with cold water at intervals, some of the organic components escape via the water vapor. At the same time, the molten pieces of film cool and agglomerate into pourable granular formations. The agglomerate has a relatively high bulk density and is very easy to transport.

Out DE 198 22 627 C2 a process for the production of a pulp has become known, in which a binder is added to the pulp and pressed into a molded part under the supply of heat, wherein a particle mass of a first group of particles, a proportion of plastic particles is admixed.

For the production of molded parts in the substitution of wood chips or fibers by plastic is to demand that the Plastic particles in their geometric shape and size the substituted Wood particles of chipboard or fiberboard are similar to conventional Wood-based panels similar To achieve results. For fibrous materials, therefore, the fiber content should predominate and in the case of chipboard materials the chip rate.

The commonly produced agglomerate is in a variety of forms and Sizes before, is therefore unsuitable as a raw material in the production of wood-based materials, because when mixing because of the different sizes of Fractions shows a strong separation behavior. Board materials, which are produced with these two fractions, due to local Agglomeratansammlungen mostly on the workpiece surface uneven surface image and make the insufficient mixing of both fractions visible, noticeable. In addition, due to the insufficient mixing the Training a consistent Plastic-plastic or plastic-wood structure with a homogeneous microstructure not guaranteed. Outside are the desired mechanical properties, e.g. Transverse tensile strength, bending strength and also behavior in the case of moisture, such as swelling behavior and water absorption, not available.

Like in the DE 103 26 181 A1 As already described, comminuted agglomerate is therefore used, for which various grinding technologies can be used. For the manufacturer of wood-based materials, who also want to use ground plastic agglomerate, it remains only to obtain either ground plastic agglomerate from a third party or to invest in a complex milling device.

A similar Problem arises with manufacturers, the materials of others Producing fibrous materials, e.g. from vegetable fibers, such as flax or Hemp or glass or carbon fiber. Should these fibers with Fibers made of recycled plastic are mixed for manufacturing a corresponding fiber material, the plastic agglomerate would have either ground by the manufacturer, which is a suitable Grinder required or ground from third party be, which also requires a relatively high effort.

Of the Invention is based on the object, a process for the preparation a fibrous material for the Specify manufacture of molded parts, in which the effort for use of shredded or ground recycled plastic is significantly reduced.

These The object is solved by the features of claim 1.

According to the invention is a Particle or fiber mass of a first group of particles and / or Fibers a proportion of plastic particles and / or plastic fibers blended with a particle size approximately equal to the particles or fibers of the first group, wherein the plastic particles and / or Plastic fibers by crushing and / or defibering pure or Mixed plastic agglomerates are recovered in a disk refiner. in this connection becomes the disk refiner during the crushing process supplied water as a lubricant. disc refiner are conventional Devices, such as those used in the wood-based material industry for defibration of larger wood particles or wood chips to find extensive use. The size of the crushed Plastic particles are adjusted by the distance of the discs. With coarser Agglomerate is optionally carried out a stepwise crushing by gradually reducing the disc gaps in the refiner.

at The crushing of plastic in the refiner is also used for cooling purposes Water added. This prevents that during the crushing process the plastic melts and smears on the disc surfaces. The water works, as mentioned, Furthermore as lubricant and lubricant between the refiner discs.

Film materials predominantly a linear molecular orientation which is caused by stretching or stretching processes in the production, e.g. in polyethylene or Polypropylene films. This has the consequence that agglomerates of this starting plastic prefers in one direction, namely the original one Preferred direction, easier to separate. The crushing process of agglomerated Pure plastic agglomerates in the refiner makes this property use and make possible with the radial groove-like Structure of the refiner discs, which are predominantly oblong, fibrous appearance of defibred low-melting pure plastic agglomerates. By change the disc distance in the refiner is a relatively well-defined Fiber size reached. Thus, it is possible the fiber size of the agglomerate plastic the size of the wood fibers adapt to the further manufacturing process one homogeneous microstructure to achieve.

With the method according to the invention It is also possible to comminute mixed plastic agglomerates. It will be the mixed plastic particles by processing in the refiner proportionately to particles on the one hand and to fibers on the other hand of defined Size crushed. The proportion of fibers on the one hand and the particles on the other hand varies naturally dependent from the composition of the mixed plastic agglomerate. The higher the Foil plastic content in the agglomerate is the greater also the proportion of plastic fibers resulting from the refining process.

Of the Manufacturer of wood-based materials or molded parts made of wood-based material, Such as plates or other items can therefore with the help already existing equipment the recycled plastic in so far process the agglomerated state with your own resources, that he the wished Substitution material for the production of moldings has available. The recycling rate of agglomerated recycled plastics is currently still relatively low, since so far hardly meaningful applications for this exist. The reason for that is that mixed plastics usually have substance contents that do not melt at all. Even at high temperatures, often only a viscous mass, even with increasing warming does not become fluid. On the other hand, mixed plastics already contain varieties 105 to 115 ° C melt. If this melting point is exceeded, decompose these plastics to carbon with outgassing of carbon dioxide and water.

The inventive method is not limited on the application to wood-based materials, but is in the use of other fiber raw materials, e.g. made of flax, hemp, glass or carbon materials equally advantageous.

Prerequisite for the method according to the invention is a disc refiner, with the help of synthetic fiber material can be produced in exactly adjustable size without additional milling, for example in the production of wood-based panels with plastic components or other molded parts made of fiber materials with plastic components.

To An embodiment of the invention, it is advantageous if the off The plastic particles or fibers coming from the refiner are subsequently dried become. Drying can be carried out in industry-standard drying facilities which are also used in production facilities for the production of Wooden materials available stand.

It may be advantageous, plastic agglomerate alone in the disc refiner to shred or to shred. However, it is equally possible a mixture of coarser ones Wood particles and plastic agglomerate in one operation in the disc refiner to crush. In this way, for the wood as well as for the plastic an approximate same particle size obtained. additionally will be a good mixing of the plastic with the wood particles reached.

below some examples of a fiber material which has been produced by the process according to the invention is as well as for the inventive method.

Example 1:

Defibration of pure plastics in a disc refiner

• Plastic raw material: low-melting pure plastic agglomerate from film residues, grain size <10mm
• Cool- and lubricant: water, temperature 10 ° C, based on 300% Amount of plastic agglomerate

Example 2:

Crushing mixed plastic agglomerates and wood particles in a disc refiner

• Wood raw material: wood particles, span-shaped, length up to 10 mm, wood moisture about 6 %
• Plastic raw material: Mixed plastic agglomerate, particle size <10mm
• Cool- and lubricant: water, temperature 10 ° C, based on 300% Amount of wood particles plastic agglomerate

Claims (13)

A process for the production of a pulp, in which a proportion of plastic particles and / or fibers is admixed as a second group to a first group of particles and / or fibers, for the production of molded parts, in which a binder is further added and the pulp is added to a molded part is pressed under the supply of heat, characterized in that the plastic particles and / or fibers are obtained by crushing and / or fiberization of agglomerates of pure or mixed plastic in a disc refiner, wherein the disc refiner during the crushing process water is supplied and the particle size of the Plastic particles and / or fibers corresponds approximately to the particle size of the particles or fibers of the first group. Method according to claim 1, characterized in that that exclusively pure plastic agglomerate is shredded in the disc refiner. Method according to claim 1 or 2, characterized that the Particles and / or fibers of the plastic are dried after crushing. Method according to one of claims 1 to 3, characterized that the first group of particles and / or fibers by defibering flax, Hemp glass or carbon materials is obtained. Method according to one of claims 1 to 3, characterized that the first group of particles and / or fibers by crushing or fiberizing is obtained from wood. Method according to Claims 1 and 5, characterized that mixed plastic and / or pure plastic agglomerate together with the wood in a disk refiner to particles and / or Fibers is crushed. Method according to Claim 6, characterized that in the disc refiner a good mixing of plastic and / or Holzpartiklen and / or plastic and wood fibers achieved becomes. Method according to one of claims 1 to 7, characterized that the Temperature of the supplied Water at most 50 ° C is. Method according to one of claims 5 to 7, characterized that the water is over wet Wood particle is fed to the disc refiner. Method according to one of claims 1 to 7, characterized that the water is gaseous Condition supplied to the refiner becomes. Method according to one of claims 1 to 9, characterized that the maximum size of the plastic agglomerate 40 mm. Method according to one of claims 1 to 11, characterized that the material to be shredded and / or to be shredded via a Stuffing screw fed to the refiner becomes Application of the method according to one of claims 5 to 10 on the production of wood-based parts, in particular of Fiberboard, adding the wood particles or wood fibers partially by plastic particles or fibers of ground agglomerates be replaced by recycled plastic.