DE3644067C2 - Process for gluing fibers, filaments, chips or similar pourable raw materials and device for carrying out the process - Google Patents

Description

The invention relates to a method for loading Glue fibers, threads, shavings or similar pourable raw materials according to the upper Concept of claim 1 and a Vorrich device for performing the method according to at least any of claims 1-13.

The gluing of raw materials of interest here the type, preferably of fibers or chips from Zel Up to now, lulose or lignocellulose has been used either in Wet process or dry process. When wet ver will drive a solution, a dispersion or a Emulsion of the desired binder in poss very low-viscosity form in the raw material brings what, for example, by injecting in the Manufacturing process also moved the flow of raw materials by otherwise introducing the binder solution can be done in the mixing container. Especially with the Manufacture of fiber mats but also of chipboard is in this liquid introduction of the bindemite disadvantageous that a not inconsiderable part of the low-viscosity adhesive completely into the mate rial penetrates and thus as a binder between the individual raw material particles are no longer available stands. The known liquid processes therefore work with a high binder content to achieve the desired Bond between the raw material particles, such as fibers or chips to ensure. A disadvantage of this wet process is also that the high Lö  proportion of the medium through appropriate heat knocking out the finished fiber mat or chipboard this must be applied, for which a high energy the end product with corresponding costs more expensive. This wet insertion is particularly disadvantageous Binder even when very expensive agents, for example thermosets, for certain Properties of the end product are prescribed.

A certain improvement brings a known one here Foam impregnation process, which is just if a wet introduction of the binder in the Fiber or chip material is concerned, but the large surface area of the wet foam is the reason for this that relatively small amounts of binder solutions sufficient to have a homogeneous distribution of the same to guarantee about the raw material at the same time reduced need for binders. This is over the DD-PS 59 550 ver a device for mixing different liquids and several glue components known, the glue from at least one liquid and is made from dry binders and additional air for foaming is supplied. The foam thus obtained is poured onto the pourable Applied raw material. Here is a glue first manufactured and only then added the air. The foam-like consistency of the binder works that otherwise for a quick suction of the Binder solution in the chip or fiber material responsible capillary force largely  loses its effectiveness and drying out the binder solution can be designed that the binder is preferably on the upper surface of the fibers or chips is deposited, without to a considerable extent in the chips themselves to penetrate. The with the drying process of the Foam usually associated viscosity increase also ensures that the bandage medium on the surfaces of the raw material particles be held. Thus, the well-known Foam impregnation process compared to pure wet process is more economical, it is however, especially with high capillaries Raw materials such as pulp or lignocellulose, not preventing a still high Proportion of dissolved or dispersed binder penetrates into the interior of the raw material particles and thus the adhesive that is deposited there for its real purpose, namely together holding the raw material particles together, is lost.

To that extent through the foam impregnation reduced but not eliminated Disadvantages of the known wet process will be in the ge also to the state of the art hearing dry processes avoided. Here will for example in the manufacture of random fiber mat powdered binder in free-flowing dry state along with the free-flowing Mixed fibers or the powdery bandage simply sprinkled on the fiber mat. The use of powdered too  fibrous dry binders guaranteed once that these are only between the Tangled fibers of the mat are present without being in the Being able to penetrate fiber material itself, and, moreover, that an evaporation of Solvents but also water as a binding middle carrier can be completely eliminated. After is part of this pure dry process however, that the pourability of the dry Binder on the one hand and that of the raw material particles on the other hand is different, so that by inevitable vibrations, especially in mat manufacturing, especially but also through the usual use of Vacuum to fix the on a band conveyor of scattered fiber material to Ent phenomena of mixing between the fibers or similar particles and the interspersed Binders and thus to inhomogeneities both about the surface as well as the thickness of the Mat or a corresponding plate comes. Such inhomogeneities in the binder ver division influence further production process and those placed on the end product Quality requirements partly in one intolerable dimensions disadvantageous. The further given compulsion to use only less Amounts of binder for such materials exacerbates this problem because Inhomogeneities occurring as a percentage appear more strongly.

This is where the present invention comes in the task is based, an extremely homogeneous  Distribution of binders both over the Area as well as the thickness of a flat Intermediate or multi-dimensional molded end product with simultaneous Minimizing the addition of binding agents put.

This object is achieved according to the invention by the in the characterizing part of patent claim 1 specified characteristics achieved.

Advantageous refinements and developments this task solution, also with regard to Device for performing the Invention according procedure, result from the sub claims.

The present procedure is independent whether from the glued fibers or The chips then still flowable overall Material directly to molded parts such as furniture, doors, Ver transport pallets or the like pressed, or whether the glued fibers, Chips or the like to a corresponding one flat mat to be pre-compressed, which then in turn through the application of pressure and heat processed into suitable end products can. The predeterminable high homogeneity of the Binder distribution and their low penetration guarantee probability in the raw material minimize the amount of binder with increased quality and use efficiency of the end products to be manufactured.  

It is convenient for distributing the Binder within the fiber composite or similar raw material particles until hardening of the binder phase separation between before the actual in the solid state lying binder powder and the binding medium in powder or fiber form to the upper surfaces of the raw material particles foamable liquid. It is advantageous moreover, that in the present Ver drive in addition to the use of fixed or dry binders as well can find such application in the Carrier medium, i.e. the foamable transport liquid can be dissolved, dispersed or emulsified, the latter binder additives can have properties at the same time, which increase the foamability of the liquid. Because the surface and the volume of the to be mixed between the raw material particles Foam compared to the liquid phase considerably is increased, the actual one also eases Mixing process, for example in a mixing drum, resulting in additional energy savings and to shorten the procedure leads in reverse. Previously required if necessary chemical solvents for the in the binders to be brought into the liquid phase can as far as they are environmentally harmful or others have adverse properties entirely omitted.

Because the fibers to be glued or  Chips with the foam containing the binders of the carrier medium are only wetted and in that the foam immediately after this wetting is dried, that has Binder no other way than to the surface of the fibers or chips store without even mentioning the inside To be able to migrate volume of chips or fibers. Even for those in the transport liquid optionally dissolved binder components compensates for the surface tension of the foam blow, the capillary action of the porous fibers or chips to a large extent, while those with dry matter process and thus the foam dissolution in the associated increase in viscosity additionally ensures that the binders in the desired homogeneous distribution at the top surface of the raw material particles.

The foamability of the transport liquid can can also be improved in that her in a way known per se agents are added, for example activated by heat or reaction substances can be. It is particularly advantageous also if the carrier liquid together with the binder by introducing compressed gas and / or mechanical stirring movement foamed is because there are no additional chemicals are needed.

The one with the transport liquid in foamed Shape optimally distributed homogeneously  Solid binders are used when drying of the foam not only to the fiber or chip surfaces attached, but also fixed there, especially if the drying of the Foam at temperatures above the room temperature takes place and the powder and / or fibrous binder thermoplastic or have heat-adhesive properties. A further advantageous development of the vorlie process is that the in the carrier liquid may additionally existing dissolved emulsified or dispersed crosslinkable condensation resins can be, and that the drying temperature is chosen so that this binder pre-condense when drying. Condens sation resins are used as binders for cellulose or lignocellulosic materials in particular partial. Because they are drying the foam is subjected to a temperature, at which they pre-condense becomes their sticky Attachment to the fiber or chip surfaces further favored.

In the event that the mitgenom with the foam my powdery or fibrous binder Thermoplastic or other warm adhesive bandage are medium and the drying of the foam is done at a temperature that the powdery or fibrous binders softened, the clinging favored anyway of the binder to the raw material particles additionally fixed. A subsequent ent  mixing is excluded. If under the added binders crosslinkable duro are plastic resins, it is advantageous that Drying temperature of the carrier foam like this to choose that it is the crosslinking temperature this binder does not exceed, so that the full binding force of these adhesives during the final pressing of the raw activate the material mass or the tangled fiber mat and fully exploits.

Especially in the production of tangled fiber mats it is advantageous to use the dry binder to introduce fibrous, as this creates another Reduction in the proportion of transport liquid is possible.

It is also advantageous to use the thermoplastic fibers or a correspondingly granular binder design material so that its interior, so the core area, a higher softening temperature as its outer shell.

If the temperature when drying the Carrier foam is chosen so that it is higher than the softening temperature of the fiber cover, however lower than the softening temperature of the Is core material, so does the emollient Fiber covering a secure attachment and fixie tion of the binder to the surface of the pourable raw material during the bandage its core remains unchanged lasts until the end you want product. Included in the invention is the possibility ability to design the dry binders so that they  fully or partially cover fibers that are themselves no binders possess properties, but during and / or after the finish Part production act as reinforcing fibers.

In the manufacture of tangled fiber mats It is common for lignocellulosic fibers Wood fibers after plasticization hot steam treatment in a devibrator from coarse wood chips or wood chips deliver. These chips are turned into the superheated steam fibers in one downstream dryer can be dried need before going to a tangled fiber mat for example on an endless conveyor belt scatters and then pre-compacted. The Be Sizing of the fibers can according to the present Ver way of driving during various procedures steps are taken, but it is particularly important partial, the binder over the foamed Transport liquid between the fiber stream the devibrator and the drying device to lead. This results in a supply of the Transport foam and the binder in one Place at the usual way particularly great turbulence in the fiber stream lie what an additional mixing process over makes fluid. It also hits at this Procedure the binder-foam mixture on relatively damp fibers, so that the feared penetration of the binders in the Fibers or the inside of the chip alone here avoided with sufficient certainty can be. The drying device for the steam-dampened fibers, which are used for their drying can be used at the same time to dry the foamed transport liquid can be wetted, causing  Procedure and device set-up simplify additionally.

The accompanying drawing is to the fiction The procedure is schematically at one end example of an implementation device further clarify the procedure. The Presentation is limited to the Production of the foam / binder mixture and does not present the contribution this foam into a nonwoven or other pourable along the surfaces with glue impacting lumpy raw material.

As indicated in a simplified manner, the device consists essentially of a foam generating device 4 which, for example by means of an agitator in the manner of a multi-chamber mixer, foams the components which have been introduced into the device in an intensely mixing manner by blowing sufficient air into the incoming liquid. The foam produced in the foam generating device 4 is discharged through a foam outlet 6 and fed to the raw material, such as lignocellulose fibers, in a suitable manner.

On the input side the foam generating device 4 is connected to a supply line 12 which opens via a liquid pump 3 into the container 1 for liquid transport. 2 Between the liquid pump 3 and the inlet of the feed line 12 into the foam generation device 4 , another line 5 opens into the line, which in the exemplary embodiment introduces the dry powdery or fine-fiber binder into the transport liquid of the feed line 12 and mixes it. The line 5 is here a pressure line which is connected to the pressure source P and in which at least one venturi or suction nozzle 7 is inserted in the manner shown. The compressed air within the compressed air line 5 flows through the cross-sectional constriction within the suction nozzle 7 at an increased speed, in which there are inlet openings for the powdery binder, which enters the suction nozzle 7 from a storage container 9 provided for this purpose via the binder line 10 and is entrained thereby the binder 8 from the reservoir 9 together with the transport liquid 2 via the inlet connection of the feed line 12 enters the foam generating device 4 in meterable proportions.

A pressure compensation line 11 is branched abge from line 5 behind the suction nozzle 7 and is returned to the reservoir 9 in the manner shown.

Another corresponding arrangement, which largely corresponds to that of the storage container 9 for the binder 8 and the suction nozzle 7 , can additionally be inserted into the pressure line 5 , with which additives in liquid and / or solid form in a manner corresponding to the binder 8 of the transport liquid in can be added to the feed line 12 . For this purpose, an additional container 9 'for these additives 8 ' is provided, which are entered as described above via line 10 'of the second suction nozzle 7 ', which in turn with the pressure compensation line 11 'a connection between the line 5 in the transport direction behind the second suction nozzle 7 'with the reservoir 9 ' for the respective surcharge manufactures.

The possible additions of the transport liquid soluble, dispersible or emulsifiable binders, foam blowing agents or the like can be entered from the additional container 9 'or one or more additional containers, not shown, via the line 5 into the foam generating device 4 according to the method described above . However, it is also conceivable that at least some of such components are already contained in the container 1 , ie that the transport liquid 2 does not consist, for example, of pure water, but already suitable components which were mixed into the container 1 before the liquid was input, contains.

In the execution of the device according to the illustration, the connection of the line 5 to a compressed air source is particularly advantageous since the foaming effect within the foam generating device 4 is considerably strengthened and thus the distribution of the powdery binder, for example, is carried out completely homogeneously in the shortest possible time. The use of suction nozzles both for free-flowing solid components and, if appropriate, liquid components makes it possible to supply these components to the foam generating device in a manner which is particularly fault-free and, in terms of the device construction, particularly simple. Through the pressure side inlet via the feed line 12 , the foam outlet at the foam outlet 6 is still ensured even if, for whatever reason, a possible back pressure should be built up. By such a device that works regardless of the pressure level at the foam outlet, it is possible that the gluing process, for example in the manufacture of fiber mats, between the devibrator and the drying device or drying section can be carried out trouble-free, although in general there Fiber flow is still a significant overpressure.

Claims (17)

1. A process for gluing fibers, filaments, chips or the like. Pourable raw materials, in which the glue is made of a liquid and dry binder, in which air is supplied for foaming and in which the foam is brought up on the pourable raw material , characterized in that the dry binder is introduced into the air in particulate form and that the air / binder mixture is mixed with a foamable transport liquid and then foamed. 2. The method according to claim 1, characterized in that at least partially hydrophilic raw materials used for gluing be, and that the binders at least go are oblong hydrophobic. 3. The method according to claim 1, characterized in that with the transport liquid in addition to the fine particulate other binders dissolved in binders, dispersed or emulsified.   4. The method according to claim 3, characterized in that the additional Binder before foaming in the Transport liquid dissolved, dispersed or be emulsified. 5. The method according to claim 3, characterized in that the additional Binder during the foaming process the transport liquid dissolved, dispersed or be emulsified. 6. The method according to claim 1 to 5, characterized in that the transport rivers liquid by adding binders foaming properties are conferred. 7. The method according to at least one of claims 1 until 6, characterized in that the the binder containing transport liquid through foam blowing agent, introduction of compressed gas and / or mechanical movement is foamed. 8. The method according to at least one of claims 1 to 7, characterized in that the drying of the Transport liquid at temperatures above the room temperature, however, is below a temperature rature required for complete condensation lead at least one binder component would be done.   9. The method according to at least one of claims 1 to 7, characterized in that as in the Transport liquid dissolved, emulsified or dispersed binders crosslinkable condensate tion resins are used, and that the dry temperature for the transport liquid so it is specified that these binders precon densify. 10. The method according to at least one of the claims 1 to 9, characterized in that the fine particles mig added binder fiber, powder, or other particulate thermoplastic are resins or thermally adhesive binders, and that the temperature for drying the Transport liquid is specified so that these binders during the drying process soften the ganges at least partially. 11. The method according to at least one of the claims 1 to 9, characterized in that the dry bandage medium fiber or powdery thermosetting Are binders, the temperature at the on drying of the transport liquid chosen is that it is the crosslinking temperature of this Binder at least does not exceed.   12. The method according to at least one of the claims 1 to 11, characterized in that fine particle or fibrous dry thermoplastic binder tel consists of an inner core with higher Softening temperature and an outer shell with a lower softening temperature be trained and that the temperature for drying the transport liquid like this is chosen to be higher than the softening temperature of the particle shell, but lower than the softening temperature of the particle cores is. 13. The method according to at least one of the claims 1 to 12, characterized in that the transport rivers additional substances in the form of color pigments, fire retardant fabrics or the like Chen added in solid or liquid form become. 14. Device for gluing fibers, filaments, chips or similar pourable raw materials for carrying out the method according to at least one of claims 1 to 13, wherein the glue is made of a liquid ( 2 ) and a dry binding agent ( 8 ) with a supply line ( 12 ) for the glue, with a pump ( 3 ) for the liquid ( 2 ) in the supply line ( 12 ), with a pressure line ( 5 ) for supplying air into the supply line ( 12 ) and with a foam generator ( 4 ), into which the supply line ( 12 ) opens, characterized in that a suction nozzle ( 7 ) is provided in the pressure line ( 5 ), via which the binder ( 8 ) predetermined in fine particles can be introduced into the pressure line. 15. The apparatus according to claim 14, characterized in that the binder ( 8 ) via a binder line ( 10 ) in the region of the cross-sectional constriction of the suction nozzle ( 7 ) opens into the pressure line ( 5 ), and that between the outlet of the suction nozzle ( 7 ) and the inlet of the pressure line ( 5 ) in the feed line ( 12 ), a pressure compensation line ( 11 ) is inserted, which is connected to the pressure line ( 5 ) in the flow direction behind the suction nozzle ( 7 ). 16. The apparatus of claim 14, characterized in that when using in a devibrator made from dry chips provided wood fibers as raw materials for the bindemite tel / transport liquid foaming between the devibrator and air drying in the Fiber flow is initiated.   17. Device according to claims 14 and 15, characterized in that at least one white tere suction nozzle ( 7 ') for the admixture of further liquid and / or solid additives is connected to the pressure line ( 5 ).