HONEYCOMB COMPOSITE SUPPORT PART AND METHOD FOR COATING IT
A method for coating a cellulose honeycomb composite support part (1), which has a multiplicity of channels which extend in an axial direction, with an impregnating coating in order to increase the fire and/or water resistance and/or mechanical stability. The impregnating agent is fed into a vacuum coating chamber (8) and a complete and axially continuous coating is produced in the channels on their inner circumferential surfaces by deposition of impregnating agent on the inner circumferential surfaces of the channels, and excess impregnating agent (13) is extracted from the vacuum coating chamber (8). The resulting coating structure and a device for coating the composite support are also disclosed.
The invention relates to a method for coating a honeycomb composite support part which has a multiplicity of channels extending in an axial direction, which consists of a cellulose, in particular paper or board (honeycomb body for constructive, preferably structural applications, in particular corrugated board honeycomb part or expanded honeycomb body), with an impregnating coating in order to increase the fire and/or water resistance and/or the mechanical stability.
Honeycomb composite support parts, in particular for use as honeycomb core material in composite workpieces are known, where the honeycombs of the honeycomb composite support part are formed by a plurality of channels extending in an axial direction, which are delimited circumferentially by carrier papers and corrugated papers glued to the carrier papers.
Known from DE 36 31 185 A1 is a method for producing shaped composite paper honeycomb articles in which a paper honeycomb part, i.e. a honeycomb composite support part having a plurality of axial channels is coated with a curable liquid synthetic resin system. For the coating the honeycomb composite support part is dipped into a dipping basin filled with the synthetic resin system, where the space above the dipping basin is evacuated. The synthetic resin systems used possibly increase the water resistance but not the fire resistance of the paper honeycomb. In addition, application of the known method on a commercial scale is difficult since it is only possible to proceed in a batchwise manner. Also the channels of the honeycomb composite support part cannot be coated with arbitrarily viscous or water-containing impregnating agents (e.g. by water-containing inorganic suspension) by the known method since the paper honeycombs absorb the water, as a result lose strength and the honeycomb structure becomes soft and even collapses.
A method for fabricating honeycomb composite support parts is described, for example, in DE 103 05 747 A1. Other honeycomb composite support parts (corrugated cardboard support parts) are shown in DE 196 54 672 A1 and DE 198 20 493 A1.
In order to coat the channel inner walls commercially with impregnating agent, the applicant has developed a method in which the corrugated board web, consisting of a carrier paper and a corrugated paper glued to this, is coated on both sides with impregnating agent by spraying before the gluing to form a honeycomb composite support part. The known method has provided successful for commercial manufacture. A disadvantage however is that with the known method not all the channels can be coated axially continuously in their interior since those channels of the corrugated board web which are delimited by the carrier paper and the corrugated paper cannot be reached by spraying from outside nor in their interior.
Starting from the aforesaid prior art, it is the object of the invention to provide an improved coating method for honeycomb composite support parts which is suitable for commercial application and which furthermore ensures that all the channels of the honeycomb composite support part can be provided with an impregnating layer on their inner circumference and that in addition is suitable for the processing of water-containing impregnating agents, in particular cement-based. Furthermore a honeycomb composite support part coated in this way and a correspondingly improved coating device are to be provided.
SUMMARY OF THE INVENTIONThe foregoing object is achieved in accordance with the present invention which is based on the idea, unlike the previous prior art, of applying the impregnating coating neither by dipping the honeycomb composite support part made of a cellulose/pulp such as paper or board (component consisting of a honeycomb composite or component comprising a honeycomb composite) into an impregnating bath nor by spraying a corrugated board web before gluing to form a multilayered honeycomb composite support part but by applying the impregnating coating in a vacuum coating chamber. Impregnating agent, preferably also air is fed into the vacuum coating chamber and the impregnating agent is deposited on the inner circumferential surfaces, preferably of all the channels so that a coating is obtained which is axially continuous in relation to the longitudinal extension of the channels and inner-circumferentially closed (complete). The vacuum (negative pressure in relation to the ambient pressure) helps to ensure that the fluid impregnating agent flows as a stream, preferably comprising air with impregnating agent droplets/impregnating agent mist located therein, through the axial channels and is thereby deposited on the inner circumferential surfaces.
Therefore preferably a stream of finely nebulised coating agent and air is formed in the vacuum coating chamber, which flows through the channels where impregnating agent is deposited in the channels. Excess impregnating agent is removed from the vacuum coating chamber, in particular is extracted or sucked out together with the preferably sucked-in air. By means of the coating of the cellulose honeycomb composite support part in a vacuum chamber according to the invention, it can be ensured for the first time that all the cellulose upper layers of the honeycomb composite support part are provided with a closed coating. The coating in a vacuum coating chamber also prevents any softening of the cellulose material even when, which is preferred, water-based impregnating agent is used. This preferably comprises a cement-water mixture, i.e. a cement glue, in particular comprising microcement. Additionally or alternatively other, preferably inorganic suspensions can be used, which are preferably water-containing.
It is particularly expedient to feed the impregnating agent into the vacuum chamber via at least one nozzle above the honeycomb composite support part and suck out in a region below the honeycomb composite support part so that the vacuum of the impregnating agent stream (preferably impregnating agent droplets in air) sucks or pulls through the channels.
It is quite particularly preferred if the impregnating agent in the vacuum coating chamber is swirled with the aid of incoming air to form the aforementioned fluid stream of finely nebulised coating agent and air. It has proved to be particularly advantageous if the impregnating agent is sucked in via gaps from the surroundings, i.e. from outside into the vacuum chamber. For the case of through-transport of the honeycomb composite support part to be coated through the vacuum coating chamber, it has proved advantageous if the air is sucked in through the gap surrounding the honeycomb composite support part upon entry into the chamber and/or exit from the chamber. By sucking in air through gaps, a high air flow rate can be achieved which is conducive to a good nebulisation (turbulence). A further advantage of the use of a vacuum chamber consists in that pore air is extracted from the cellulose by using vacuum and furthermore the impregnating agent adheres intensively to all the surfaces of the cellulose honeycomb composite support part to be coated. Preferably the air stream laden with excess impregnating agent (for the simultaneous production of the vacuum) is sucked out from the vacuum coating chamber during the coating, where it is particularly preferred if the impregnating agent is deposited, for example, through the widening of the air stream against a baffle plate and then fed to the vacuum coating chamber, in particular via nozzles disposed in said chamber.
The method according to the invention is particularly suitable for the use of water-containing impregnating agents with inorganic additives, quite particularly preferably cement, even more preferably microcement. With the method a commercial coating of all the channels of a honeycomb composite support part can be ensured for the first time.
There are various possibilities with regard to the configuration of the honeycomb composite support part. It is essential that it comprises a honeycomb body of cellulose, in particular paper or board. This can be produced in a manner known per se in various types, for example, by the gluing together or several corrugated board layers, alternatively the honeycomb composite support part is fabricated from a so-called expanded honeycomb body, i.e. a pull-apart honeycomb element, where in principle Kraft liner papers, test liner papers or bogus papers are suitable.
An embodiment of the method is particularly expedient in which a relative movement is achieved between the cellulose honeycomb composite support part having a plurality of honeycombs in the form of axial channels and the vacuum coating chamber in which the honeycomb composite support part is provided with the coating, and this is preferably perpendicular to the axial extension of the channels.
Here it is particularly preferred to move the honeycomb composite support part relative to a fixed coating device, in particular through the vacuum coating chamber. At the entrance to the vacuum coating chamber and at the exit from the vacuum coating chamber, a small gap is preferably formed around the honeycomb composite support part through which air is sucked into the vacuum coating chamber, in particular to ensure an extremely fine nebulisation of impregnating agent, preferably introduced via spray nozzles. It is also feasible, additionally or alternatively to a sucking in of air, to blow air into the chamber for nebulisation purposes. It is also feasible to proceed batchwise, whereby the honeycomb composite support part is not transported through the vacuum coating chamber but is received therein during the coating. In this case, air can be sucked in via appropriate, in particular slit-shaped or gap-shaped, openings.
Fundamentally it is also possible to move the honeycomb composite support part and the coating device relative to one another, preferably in mutually opposite directions.
By achieving a relative movement between honeycomb composite support part and coating device, the commercial applicability can be further improved since whilst some of the channels have an impregnating agent stream (preferably air+impregnating agent) flowing through them, the honeycomb composite support part moves relative to the coating device, in particular through the vacuum coating chamber. As a result the length of the honeycomb composite support part is not restrictive. The coating can be accomplished quasi-continuously without the need to have to achieve a very large vacuum coating chamber [which] receives the entire honeycomb composite support part and at the same time coats all the channels (which is alternatively possible).
In order to produce the negative pressure, a suction pump or a suction fan is expediently assigned to the vacuum chamber in order to produce the corresponding pressure difference in relation to the surroundings. It is particularly expedient here if, as mentioned initially, the excess, i.e. non-deposited impregnating agent is sucked out via this suction means together with air which has been fed in, in particular sucked into the vacuum chamber.
By means of the invention it is also possible to optimally coat a honeycomb composite support part fabricated from a pull-apart honeycomb element (expanded honeycomb), in particular made of Kraft liner paper, test liner paper or bogus paper, which is not produced by gluing together a plurality of corrugated board webs.
Preferably the excess impregnating agent, i.e. which has been removed, in particular sucked out, is conveyed in the cycle, i.e. fed again to the channels for coating, where it is particularly expedient if the removal-side impregnating agent is collected or fed to a collecting container from which impregnating agent is then extracted again by means of a conveying pump for supply to the channels.
As indicated initially, it is particularly expedient if the impregnating agent preferably comprises cement mixed with water, in particular a cement mixture, preferably a mixture of microcements and/or waterglass and/or inorganic suspensions, preferably a mixture of water with an inorganic binder such as, for example, cement or chalk.
Particularly preferred is a variant of the method in which at the same time as the coating in the vacuum coating chamber and/or after the impregnating agent coating, the channels are filled with a filler material, in particular a heat insulating material which can be pressed in and/or blown in and/or sucked into the channels. Preferably this filler material is present in the form of particles, preferably having a grain size of less than 2 mm, preferably between 0.05 mm and 2 mm. It is quite particularly expedient if this filler material is mixed with the impregnating agent so that the mixture in the form of an impregnating agent stream can be conveyed through the channels for the purpose of coating. The heat insulating material can be foam glass, for example Misapor and/or insulating pearls, for example, made of Styropor and/or polystyrene and/or silicic acid, where it is particularly expedient to use old or waste materials for this purpose, which can optionally be ground to the preferred grain size (size). It is also possible (additionally or alternatively) to use in particular light construction material such as expanded clay or Ytong as heat insulating materials. By means of the aforesaid heat insulating filling, considerably better insulation values are achieved and the honeycomb structure formed by the channels is additionally strengthened.
According to one variant of the method, suction of the filling material and/or a mixture of impregnating agent and filling material can be dispensed with and instead of this, for example, the filling material or the impregnating agent coating-filling material mixture can be stripped mechanically on the removal side of the vacuum coating chamber in order to ensure that the channels remain filled. During a subsequent filling of the channels with filling material, i.e. during an introduction of the filling material after the impregnating agent coating, in particular after the drying of the impregnating agent coating, it is advantageous if the honeycomb composite support part is sealed on one side, in particular on a removal side. To this end the honeycomb composite support part can be laminated with a paper, a cardboard and/or a plate.
It is particularly expedient to feed the mass consisting of impregnating agent and heat insulating material in particular on the feed side arranged at the top and optionally introduce it into the channels, in particular press it in under pressure, for example, by means of a pump and/or mechanically, for example, by means of a doctor blade and then remove, in particular draw off or extract the excess mass on the removal side, in particular with the aid of negative pressure.
At this point it is expressly noted that the provision of filling material in particular heat insulating material in the channels of the honeycomb composite support part should be considered to be disclosed as an independent invention and should be claimable for example by way of a divisional application. It is preferable to additionally provide the heat insulating material to form a complete and axially continuous impregnating agent, in particular by the heat insulating material flowing together with the impregnating agent through the channels. However, it is also feasible to provide the heat insulating material without impregnating agent or in another way, in particular introduce it by itself into the channels.
It is particularly expedient if the honeycomb composite support part coated according to the invention, in particular for producing a sandwich component comprising two cover layers spaced apart via the honeycomb composite support part is provided with at least one cover layer, where the cover layer can, for example, consist of wood, board, foamed plastic or plywood or aluminium foil or paper or metal sheet. In this case, the surface extension of the cover layer is aligned perpendicular to the longitudinal extension of the channels.
It is quite particularly preferred if the honeycomb composite support part is provided with different cover layers on two sides facing away from one another, which for example differ in their thickness extension (strength) and/or with regard to the selected materials. Alternatively identical cover layers can be used. For example, channelled sheets, steel sheets, stainless steel sheets, copper sheets, zinc sheets or aluminium sheets are used as cover layers, possibly also in different alloys. It is also feasible to use copper plates.
The invention also leads to a honeycomb composite support part which is preferably coated by a method executed according to the concept of the invention where it is particularly preferred if all the channels on their inner circumference are provided with a complete and axially continuous impregnating coating. It is particularly expedient if the channels are additionally provided with filling material, in particular heat-insulating material, in particular are filled axially continuously.
The honeycomb composite support part can preferably consist of a plurality of glued-together layers of corrugated board web where the plurality of layers can also consist of a single web or can be fabricated from this, in particular when the honeycomb composite support part is produced by winding up a corrugated board web whilst simultaneously gluing the same to itself. It is essential that a plurality of corrugated board layers are achieved perpendicular to the longitudinal extension of the channels. Instead of winding up corrugated board webs, it is also possible to layer a plurality of corrugated board webs parallel and glue them together. The winding method is described, for example, in DE 103 05 747 A1. Alternatively the honeycomb composite support part can consist of an extendable honeycomb element, i.e. can be configured as expanded honeycomb element.
The corrugated board webs, i.e. the layers of the honeycomb composite support part made from corrugated board webs comprise first and second channels where the first channels are formed between a carrier paper of the layer and a corrugated paper of this layer. The second channels are formed between the corrugated paper of the layer and either a carrier paper of the adjoining layer or another carrier paper of the same layer depending on which type of corrugated board web is used, i.e. either a corrugated paper web comprising a single carrier paper which is glued to a single corrugated paper or a corrugated paper web in which the corrugated paper is included in sandwich fashion between two carrier papers.
Preferably no impregnating agent is found between the corrugated paper and the carrier paper at any joining point at which the corrugated paper is glued to carrier papers, as is the case when the corrugated paper web when, as in the prior art, the corrugated paper web is sprayed from outside before the gluing to form the honeycomb composite support part. In the method according to the invention, flow takes place through the finished channels, i.e. in a honeycomb composite support part which has already been glued, so that exclusively glue should be present in the joining regions between the corrugated paper and the carrier papers.
As mentioned, instead of gluing together corrugated board webs comprising respectively one corrugated paper and at least one carrier paper, the honeycomb composite support part can be or become formed as so-called expanded honeycomb. Expanded honeycombs are significantly cheaper to manufacture than the honeycomb body produced from a plurality of corrugated cardboard webs.
As already indicated, it is particularly expedient if a filling material, in particular a heat-insulating material or sound-insulating material is provided in the coated channels, where this heat-insulating material or sound-insulating material should preferably be provided at least approximately over the entire longitudinal extension of the channels and where naturally individual neighbouring particles of the filling material can be spaced apart from one another in the direction of the longitudinal extension of the channels. Preferably the filling material is introduced into the channels together with the impregnating agent in the form of the impregnating agent stream containing the filling material in the vacuum coating chamber.
It is particularly expedient if the honeycomb composite support part, in particular a composite material fabricated with this, comprises at least one gas and/or water-vapour inhibiting or impermeable plastic or metal film where it is even further preferred if the honeycomb composite support part is enveloped with such a film. Preferably at least one axial side of the channels, even more preferably both axial sides of the channels should be sealed with at least one plastic film and/or a metal film.
The invention also leads to a coating device or its use for coating cellulose honeycomb composite support parts. The coating device according to the invention is characterised by a vacuum coating chamber into which impregnating agent but preferably not necessarily air is supplied. In order to produce the vacuum (negative pressure in relation to the surroundings) in the vacuum coating chamber, this is assigned appropriate vacuum generating means, in particular a suction pump or a suction blower, where air is preferably also sucked into the vacuum coating chamber via these, in particular via appropriate slits or gaps. The air is preferably sucked in or blown in at such a high speed that an optimal turbulence/nebulisation of the impregnating agent takes place and the fluid stream of air and droplet-shaped impregnating agent flows through the channels, where impregnating agent is deposited completely and axially continuously as coating. Preferably the honeycomb composite support part is preferably guided through the vacuum coating chamber by means of suitable means, for example, a conveyor belt, a conveyor chain or by feeding and/or pulling means. Here it is particularly expedient if the vacuum coating chamber has an inlet opening and an outlet opening for introducing or removing the honeycomb composite support part where a preferably circumferential gap is formed between the edge of the inlet opening and the cellulose honeycomb composite support part and the edge of the outlet openings and the honeycomb composite support part, through which air is sucked in by means of vacuum generating means. Preferably separator means are provided downstream of the vacuum coating chamber in order to separate the impregnating agent from the sucked-out air stream containing impregnating agent droplets, in particular by directing this against a baffle plate or by reducing the flow rate by means of an appropriate expansion (cross-sectional enlargement). The separated impregnating agent can then be fed by means of a suitable conveyor pump back to the vacuum coating chamber, in particular via at least one nozzle.
Further advantages, features and details of the invention are obtained from the following description of preferred exemplary embodiments and by reference to the drawings. These show in:
In the figures the same elements and elements having the same function are identified with the same reference numbers.
DETAILED DESCRIPTIONAs can be seen from
A coating device 7 is shown highly schematically in
In any case, it is essential that impregnating agent which is preferably nebulised or present in an air-droplet mixture enters into all the channels 5, 6 inside the vacuum coating chamber 8 and impregnating agent is separated there where excess impregnating agent 13 is extracted together with the air sucked in through the gap 12 via suction means 11 and is preferably separated from the air, where the impregnating agent is then again fed via the feed means 9 to the vacuum coating chamber 8.
If required, filling material can already be added, in particular blown into an impregnating agent stream inside the vacuum coating chamber 8. Quite particularly preferably this comprises heat insulating material and/or sound insulating material in the form of particles, in particular balls, which are deposited in the channels 5, 6, preferably over the entire longitudinal extension of the channels 5, 6.
Claims
1-17. (canceled)
18. A method for coating a cellulose honeycomb composite support part (1) having a multiplicity of channels extending in an axial direction, with an impregnating coating in order to increase the fire and/or water resistance and/or mechanical stability, comprising the steps of:
- (a) feeding an impregnating agent into a vacuum coating chamber (8) to form a complete and axially continuous coating in the channels (5, 6) on all inner circumferential surfaces by deposition of impregnating agent on all of the inner circumferential surfaces of the channels; and
- (b) extracting excess impregnating agent (13) from the vacuum coating chamber (8).
19. The method according to claim 18, including feeding air into the vacuum coating chamber.
20. The method according to claim 18, wherein an impregnating agent flow in the form of an air/impregnating agent mixture is produced in the vacuum coating chamber (8) by the channels (5, 6).
21. The method according to claim 18, including spraying the impregnating agent (13) into the vacuum coating chamber (8) by means of at least one nozzle, wherein the impregnating agent is nebulised turbulently by means of air sucked and/or blown into the vacuum coating chamber (8), and the swirled impregnating agent (13) is deposited into the channels (5, 6).
22. The method according to claim 21, wherein the excess impregnating agent (13) is extracted together with the intaken air.
23. The method according to claim 21, wherein the air is taken into the vacuum coating chamber (8) via at least one gap (12) between a honeycomb composite support part (1) and vacuum coating chamber (8).
24. The method according to claim 23, wherein the honeycomb composite support part (1) and vacuum coating chamber (8) are moved relative to one another perpendicularly to an axial extension of the channels (5, 6), wherein the honeycomb composite support part (1) is conveyed through the vacuum coating chamber (8).
25. The method according to claim 18, wherein the impregnating agent (13) is selected from the group consisting of cement, waterglass, chalk, inorganic binder, and mixtures thereof.
26. The method according to claim 25, including fixing a cover layer on at least one surface side of the honeycomb composite support part (1) to produce a sandwich component.
27. A honeycomb composite support part (1) comprising a plurality of coated channels (5, 6) having an inner circumference coated with a complete and axially continuous impregnating coating.
28. The honeycomb composite support part according to claim 27, wherein the honeycomb composite support part (1) comprises at least one carrier paper (3) and at least one corrugated paper (4) glued to the carrier paper (3), with a corrugated first surface side facing the carrier paper (3) to delimit first channels (5) each having a first inner circumferential surface and with a corrugated second surface side facing away from the first surface side to delimit second channels (6) each having a second inner circumferential surface, wherein the first inner circumferential surfaces of the first channels (5) and the second inner circumferential surfaces of the second channels (6) are coated with the impregnating coating to increase the fire and/or water resistance of the honeycomb composite support part.
29. The honeycomb composite support part according to claim 28, wherein a first glue layer is provided between the first surface side of the corrugated paper (4) and the carrier paper (3), wherein this glue layer in a connecting region between the corrugated paper (4) and the carrier paper (3) directly adjoins the corrugated paper (4) and directly adjoins the first surface side of the carrier paper (3), and a second glue layer is provided between the second surface side of the corrugated paper (4) and the carrier paper (3), wherein the second glue layer in the connecting region between the corrugated paper (4) and the carrier paper (3) directly adjoins the corrugated paper (4) and directly adjoins the second surface side of the carrier paper (3).
30. The honeycomb composite support part according to claim 27, wherein the honeycomb composite support part (1) is configured as an expanded honeycomb body.
31. A coating device (7) for coating a honeycomb composite support part (1) having a plurality of channels extending in an axial direction with an impregnating coating to increase the fire and/or water resistance and/or the mechanical stability, the device (7) comprises a vacuum coating chamber (8) which has means for generating a vacuum and feed means comprising at least one nozzle for feeding impregnating agent (13) into a vacuum coating chamber (8) for depositing impregnating agent (13) on inner circumferential surfaces of the plurality of channels (5, 6) for producing a complete and axially continuous coating on the honeycomb support part.
32. The device according to claim 31, wherein the vacuum coating chamber (8) has at least one gap-shaped opening for taking in air and/or the vacuum coating chamber (8) has blowing-in means for blowing in air.
33. The device according to claim 31, including means for movement of the honeycomb composite support part (1) and the vacuum coating chamber (8) relative to one another.
Type: Application
Filed: Sep 29, 2011
Publication Date: Jul 25, 2013
Inventor: Fredy Iseli (Uttwil)
Application Number: 13/878,293
International Classification: D21H 19/74 (20060101); D21H 23/42 (20060101);
