DE10330756A1 - Fiberous material production for subsequent use with binder for pressing into panels involves mixing wood based fibers and particles with plastic fibers and particles recovered from recycled material - Google Patents

Abstract

A first group of particles and fibers is mixed with a quantity of plastic particles and/or plastic fibers of similar size to those of the first group. Plastic particles and/or fibers are obtained by crushing and/or grinding pure or mixed plastic agglomerates in a disc refiner while adding water. Plastic particles and/or fibers are dried after crushing. Mixed plastic and/or pure plastic agglomerate may be mixed with wood particles in a disc refiner and ground into particles or fibers. Water added to the refiner may be either: a) at not >50[deg]C; b) contained within moist wood particles or c) as steam. A stuffing screw feeds materials to the disc refiner. Plastic agglomerates have a maximum size of 40mm and are cooked at 100-180[deg]C and 1-4 bar for 3-10minutes to remove contaminants before grinding. Following grinding particles and/or fibers are dried in superheated steam to a final moisture content and the steam is returned via a closed circuit to product to be dried.

Description

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

In the earlier patent application DE 103 26 181 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 optional Cleaning and pre-sorting comminuted into flakes or schnipseln. In order to achieve a sufficient transport bulk density, be the flakes or snippets in a so-called agglomeration process to a granular good edited. The grainy Good is depending on the purity and sorting very evenly (at high degree of purity of the plastics) or it has a very high uneven structure both the appearance and the consistency and the geometry of the agglomerate ago (high mixing of various types of plastic from different sources of origin, e.g. Mixed plastics Household collection systems). In the processing, the mentioned agglomeration, The flakes or chips are heated in a stirrer by friction so that they melt. By spraying the heated agglomerate at intervals with cold water a part of the organic components escapes via the Steam. Cool at the same time the melted foil pieces from and agglomerate to pourable granular Structures. The agglomerate has a relatively high bulk density and is very easy to transport.

at the substitution of wood chips or fibers through 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 usually on the workpiece surface a uneven surface image and make the insufficient mixing of both fractions visible, noticeable. In addition, due to the insufficient mixing the Training a continuous plastic-plastic or plastic-wood structure with a homogeneous microstructure not guaranteed. Außendem are the desired ones 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.

As in the older one Patent application already described, therefore comminuted agglomerate is used, for what different Grinding technologies can be used. For the manufacturer of wood-based materials, who also wants to use ground plastic agglomerate remains only left either ground plastic agglomerate from third party or to invest in a complicated grinder.

A similar problem arises with manufacturers who produce materials from other fibers, such as plant fibers, such as flax or hemp or glass or carbon fibers. If these fibers are mixed with fibers made of recycled plastic to produce a corresponding fiber material, the plastic agglomerate would have to be ground either by the manufacturer, which requires a suitable grinder dert or ground be obtained from third party, 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 or fibers a proportion of plastic particles and / or plastic fibers blended having a particle size approximately equal to the particles or fibers of the first group, wherein the plastic particles and / or plastic fibers by comminution and / or defibering of or mixed plastic agglomerates recovered in a disc refiner become. Here, the disc refiner during the crushing process Water or another liquid supplied as a lubricant become. Disc refiners are conventional devices, such as in the wood-based material industry for defibering 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 by a stepwise comminution Gradually reducing the disc gaps in the refiner.

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

requirement for the inventive method is a disc refiner, with the help of synthetic fiber material in exactly adjustable size without additional Grinding devices can be produced, e.g. in production of wood-based panels with plastic parts or other Moldings made of fiber materials with plastic components.

According to one embodiment of the invention, it is advantageous if the plastic particles or fibers coming from the refiner are subsequently dried. Drying can be carried out in customary drying facilities, which are also available in Production facilities for the production of wood-based materials are available.

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 for the production of molded parts, in which a binder is added to the pulp and pressed into a molded part under the supply of heat, characterized in that a particle or fiber mass of a first group of particles or fibers, a proportion of plastic particles and or plastic fibers whose particle size approximately corresponds to the particle size of the particles or fibers of the first group, wherein the plastic particles and / or fibers are obtained by crushing and / or defibering of pure or mixed plastic agglomerates in a disc refiner and the disc refiner during the crushing process Water is supplied. Method according to claim 1, characterized in that that only pure plastic 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 fibers by defibering of flax, hemp, glass or carbon materials is won. Method according to one of claims 1 to 3, characterized that the first group of particles or fibers by crushing or defibering is obtained from wood. Method according to Claims 1 and 5, characterized that mixed plastic and / or pure plastic agglomerate along with wood particles in a disk refiner to particles and / or fibers is comminuted. Method according to one of claims 1 to 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 1 to 7, characterized that the water is over wet Wood particles fed to the refiner becomes. 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 1 to 10 to the production of wood-based material parts, in particular of wood fiber boards, by the wood chips or wood fibers partially by plastic particles or fibers from recycled art be replaced.