Method for Producing an Abrasion-Resistant Wood Material Panel and Production Line Therefor

Abstract

A production line for producing an abrasion-resistant wood-composite panel that has a decorative layer, the production line including a first application device for applying a resin layer to an upper and/or lower side of a core board, a scattering device for scattering abrasion-resistant particles controlled by a light barrier and arranged downstream of the first application device in a direction of processing, a first resin drying device arranged downstream of the first application device and scattering device, a second resin application device for applying a second resin layer to an upper and/or lower side of the core board arranged downstream of the first resin drying device, a second resin drying device arranged downstream of the second application device, and at least one short-cycle press.

Claims

1. A production line for producing an abrasion-resistant wood-composite panel which has at least one decorative layer on the upper surface, the production line comprising: at least one first application device for applying a first resin layer to the upper surface and/or lower surface of a core board, at least one scattering device arranged downstream of the first application device in a direction of processing for scattering a predetermined quantity of abrasion-resistant particles; at least one first drying device arranged downstream of the first application device and scattering device in the direction of processing for drying the first upper and/or lower resin layer; at least one second application device arranged downstream of the first drying device in the direction of processing for applying a second resin layer to the upper side and/or lower side of the core board; at least one second drying device arranged downstream of the second application device in the direction of processing for drying the second upper and/or lower resin layer; and at least one short-cycle press, wherein the at least one scattering device is controlled by a light barrier.

2. The production line according to claim 1, wherein the at least one scattering device comprises a hopper, a rotating structured spreading roller and a scraper.

3. The production line according to claim 1, wherein the at least one scattering device comprises an oscillating brush system.

4. The production line according to claim 2, wherein the light barrier is arranged upstream of the spreader roller in the direction of processing.

5. The production line according to claim 2, wherein at least one hopper for collecting excess abrasion-resistant particles is provided upstream of the spreader roller in the direction of processing.

6. The production line according to claim 3, wherein the hopper is coupled to at least one conveyor device and a screening device, and wherein the excess abrasion-resistant material collected in the hopper is transported to the screening device via the conveyor device.

7. The production line according to claim 6, wherein screen meshes of the screening device correspond to the largest used grain of the abrasion-resistant particulate material.

8. The production line according to claim 1, wherein the at least one scattering device is arranged in at least one booth provided with at least one means for removing dust occurring in the booth.

9. The production line according to claim 8, wherein the means for removing the dust is in the form of a suction device and/or a device for blowing in air by means of nozzles.

10. The production line according to claim 1, further comprising: at least one third application device arranged downstream of the second drying device in the direction of processing for applying a third resin layer to the upper side and/or lower side of the core board, at least one third drying device arranged downstream of the third application device in the direction of processing for drying the third upper and/or lower resin layers; at least one fourth application device arranged downstream of the third drying device in the direction of processing for applying a fourth resin layer to the upper side and/or lower side of the core board; at least one fourth drying device arranged downstream of the fourth application device in the direction of processing for drying the fourth upper and/or lower resin layers; and at least one short-cycle press arranged downstream of the fourth drying device in the direction of processing.

11. The production line according to claim 10, wherein a scattering device for scattering glass balls is provided downstream of the third application device in the direction of processing.

12. The production line according to claim 1, wherein the at least one first drying device arranged downstream of the first application device and scattering device in the direction of processing direction dries the lower resin layer.

13. The production line of claim 1, wherein the at least one decorative layer is a printed decorative layer.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0084] FIG. 1 is a diagram of a production line for a wood-composite panel, using the process of the invention.

DESCRIPTION OF THE INVENTION

[0085] The production line presented diagrammatically in FIG. 1 comprises four double-applicator assemblies 1, 2, 3, 4 for the simultaneous application of the respective resin layer on the upper side and the underside of the unitized printed panels, e.g. of printed HDF panels, and also respectively four convection dryers 1a, 2a, 3a, 4a arranged behind the double-applicator assemblies in the direction of processing.

[0086] After the first applicator roll 1, there is moreover a first scattering device 10 provided for the uniform scattering of the abrasion-resistant material, e.g. corundum, onto the first resin layer on the upper side of the HDF panel. The first resin layer is then dried in the first convection dryer 1a.

[0087] This is followed by a second double-applicator unit 2 for the application of the second resin layer, and by a second convection dryer 2a for the drying of the second resin layer.

[0088] Downstream of the third double-applicator unit 3 for the application of the third resin layer, there can be a further scattering device 20 for the application of glass beads to the third resin layer, followed by a third convection dryer 3a for the drying of the third resin layer. The scattering device 20 for the glass beads is optional. The glass beads can also be applied together with the third resin layer.

[0089] After application of the fourth resin layer, which in the case of the fourth resin layer on the upper side can for example comprise cellulose fibers, in a fourth double-applicator unit 4 and drying in a fourth convection dryer 4a, the layer structure is pressed in a short-cycle press 5. The pressed panels are cooled and stored.

Embodiment 1

[0090] A stack of printed HDF (dark wood decorative effect) is unitized before the production line and is transported through the line at a velocity of 28 m/min.

[0091] In a first roll-applicator assembly, about 70 g of liquid melamine resin (solids content: 55% by weight) comprising the conventional auxiliaries (hardeners, wetting agents, etc.) are applied to the panel surface. The first roll-applicator assembly likewise applies a melamine resin to the panel underside (quantity applied: 60 g of liquid resin/m.sup.2, solids content: about 55% by weight).

[0092] A scattering apparatus is then used to scatter 14 g of corundum/m.sup.2 (F200) onto the surface. A distance of about 5 m before the dryer is reached allows the corundum to sink into the melamine resin. The panel then passes through a convection dryer. A quantity of 25 g/m.sup.2 of the melamine resin layer (solids content: 55% by weight) is then applied. Again, this comprises the conventional auxiliaries. A roll-applicator assembly is likewise used to apply a melamine resin to the panel underside (quantity applied: 50 g of liquid resin/m.sup.2, solids content: about 55% by weight). Again, the panel is dried in a convection dryer.

[0093] A melamine resin that additionally also comprises glass beads is then applied to the panel surface. The diameter of the beads is from 60 to 80 μm. The quantity applied of the resin is about 20 g of liquid melamine resin/m.sup.2 (solids content: 61.5% by weight). The formulation also comprises a release agent, alongside the curing agent and the wetting agent. The quantity of glass beads applied is about 3 g/m.sup.2. A roll-applicator assembly is likewise used to apply a melamine resin to the panel underside (quantity applied: 40 g of liquid resin/m.sup.2, solids content: about 55% by weight). Again, the panel is dried in a convection dryer, and is then again coated with a melamine resin comprising glass beads. Cellulose (Vivapur 302) is present as further component. Again, about 20 g of liquid melamine resin/m.sup.2 (solids content: 61.6% by weight) are applied. Here again, about 3 g of glass beads and 0.25 g of cellulose/m.sup.2 are applied. The formulations also comprise a release agent, alongside the curing agent and the wetting agent. A roll-applicator assembly is likewise used to apply a melamine resin to the panel underside (quantity applied: 30 g of liquid resin/m.sup.2, solids content: about 55% by weight). Again, the resin is dried in a convection dryer, and then the panel is pressed with a pressure of 400 N/cm.sup.2 in a short-cycle press at 200° C. Press time was 10 seconds. Structure was provided by using a press platen with a wood structure.

[0094] For comparison, a panel with corundum applied by way of a roll applicator was pressed. The quantities of resin applied were at the same level as in the case of the scattered-corundum panel. Applicator units 1 to 2 here comprised corundum-containing formulations. In the final applicator units, the resins comprised glass beads or glass beads and cellulose. The quantity of corundum applied was determined gravimetrically as about 20 g/m.sup.2. The performance of both samples in relation to abrasion was determined in accordance with DIN EN 15468. The transparency of the surface was assessed visually. The values obtained here were as follows:

TABLE-US-00001 Sample Scattered Corundum from Test corundum roll applicator Performance in 4200/4400 Um. 4000/4100 Um. relation to abrasion (DIN EN 15468) (two determinations) Transparency Good transparency Slight transparency problems in wood pores

Embodiment 2

[0095] A stack of printed HDF (dark wood decorative effect) is unitized before the production line and is transported through the line at a velocity of 28 m/min.

[0096] In a first roll-applicator assembly, about 70 g of liquid melamine resin (solids content: 55% by weight) comprising the conventional auxiliaries (hardeners, wetting agents, etc.) are applied to the panel surface. The first roll-applicator assembly likewise applies a melamine resin to the panel underside (quantity applied: 60 g of liquid resin/m.sup.2, solids content: about 55% by weight).

[0097] A scattering apparatus is then used to scatter 23 g of corundum/m.sup.2 (F200) onto the surface. A distance of about 5 m before the dryer is reached allows the corundum to sink into the melamine resin. The panel then passes through a convection dryer.

[0098] A quantity of 25 g/m.sup.2 of a second melamine resin layer (solids content: 55% by weight) is then applied. Again, this comprises the conventional auxiliaries. A roll-applicator assembly is likewise used to apply a second melamine resin to the panel underside (quantity applied: 50 g of liquid resin/m.sup.2, solids content: about 55% by weight). Again, the panel is dried in a convection dryer.

[0099] Following the drying process, again a third melamine resin is applied by a roll assembly. The quantity applied of the resin is about 20 g of liquid melamine resin/m.sup.2 (solids content: 61.5% by weight). The formulation also comprises a release agent, alongside the hardener and the wetting agent. A roll-applicator assembly is likewise used to apply a third melamine resin to the panel underside (quantity applied: 40 g of liquid resin/m.sup.2, solids content: about 55% by weight). A scattering assembly is then used to scatter about 6 g of glass beads/m.sup.2. The diameter of these was from 60 to 80 μm. Again, the panel is dried in a convection dryer and then again coated with a fourth melamine resin, which comprises cellulose (Vivapur 302). Again, about 20 g of liquid melamine resin/m.sup.2 (solids content: 56.0% by weight) are applied. 0.25 g of cellulose/m.sup.2 is applied here. A roll-applicator assembly is likewise used to apply a fourth melamine resin to the panel underside (quantity applied: 30 g of liquid resin/m.sup.2, solids content: about 55% by weight). The formulations also comprise a release agent, alongside the hardener and the wetting agent. Again, the resin is dried in a convection dryer, and the panel is then pressed with a pressure of 400 N/cm.sup.2 in a short-cycle press at 200° C. Press time is 10 seconds. Structure was provided by using a press platen with a wood structure.

[0100] For comparison, a panel with corundum applied by way of a roll applicator was pressed. The quantities of resin applied in the case of this panel were about 20 g/m.sup.2 (solid) higher than for the scattered-corundum panel. Corundum-containing formulations were used in the first three applicator units here. In the final applicator unit, the melamine resin comprised glass beads and cellulose. The quantities applied of the two components were comparable with those for the scattered panel. The quantity of corundum applied was determined gravimetrically as about 30 g/m.sup.2. The performance of both samples in relation to abrasion was determined in accordance with DIN EN 15468. The transparency of the surface was assessed visually. The values obtained here were as follows:

TABLE-US-00002 Sample Scattered Corundum from Test corundum roll applicator Performance in 6300/6500 Um. 6200/5950 Um. relation to abrasion (DIN EN 15468) (two determinations) Transparency Good transparency Greater transparency problems in wood pores and across the entire surface

Embodiment 3

[0101] In a large-scale trial, 10 000 printed HDF panels (format: 5600×2070 mm dark wood decorative effect) were unitized for the production line and transported through the line at a velocity of 28 m/min.

[0102] In a first roll-applicator assembly, about 70 g of liquid melamine resin (solids content: 55% by weight) comprising the conventional auxiliaries (hardeners, wetting agents, etc.) are applied to the panel surface. A roll-applicator assembly likewise applies a melamine resin to the panel underside (quantity applied: 60 g of liquid resin/m.sup.2, solids content: about 55% by weight).

[0103] A scattering apparatus is then used to scatter 23 g of corundum/m.sup.2 (F200) onto the surface. A distance of about 5 m before the dryer is reached allows the corundum to sink into the melamine resin. The panel then passes through a convection dryer.

[0104] A quantity of 25 g/m.sup.2 of a second melamine resin layer (solids content: 55% by weight) is then applied. Again, this comprises the conventional auxiliaries. A roll-applicator assembly is likewise used to apply a second melamine resin to the panel underside (quantity applied: 50 g of liquid resin/m.sup.2, solids content: about 55% by weight). Again, the panel is dried in a convection dryer.

[0105] Following the drying process, again melamine resin is applied by a roll assembly. The quantity applied of the resin is about 20 g of liquid melamine resin/m.sup.2 (solids content: 61.5% by weight). The formulation also comprises a release agent, alongside the hardener and the wetting agent. A roll-applicator assembly is likewise used to apply a melamine resin to the panel underside (quantity applied: 40 g of liquid resin/m.sup.2, solids content: about 55% by weight). A scattering assembly is then used to scatter about 6 g of glass beads/m.sup.2. The diameter of these was from 60 to 80 μm. Again, the panel is dried in a convection dryer and then again coated with melamine resin, which comprises cellulose (Vivapur 302). Again, about 20 g of liquid melamine resin/m.sup.2 (solids content: 56.0% by weight) are applied. 0.25 g of cellulose/m.sup.2 is applied here. A roll-applicator assembly is likewise used to apply a melamine resin to the panel underside (quantity applied: 30 g of liquid resin/m.sup.2, solids content: about 55% by weight). The formulations also comprise a release agent, alongside the hardener and the wetting agent. Again, the resin is dried in a convection dryer, and the panel is then pressed with a pressure of 400 N/cm.sup.2 in a short-cycle press at 200° C. Press time is 10 seconds. Structure was provided by using a press platen with a wood structure.

[0106] For comparison, 10 000 panels with corundum applied by way of a roll applicator were pressed. The quantities of resin applied in the case of these panels were about 20 g/m.sup.2 (solid) higher than for the scattered-corundum panel. Corundum-containing formulations were used in the first three applicator units here. In the final applicator unit, the melamine resin comprised glass beads and cellulose. The quantities applied of the two components were comparable with those for the scattered panel. The quantity of corundum applied was determined gravimetrically as about 30 g/m.sup.2. The performance of both samples in relation to abrasion was determined in accordance with DIN EN 15468. The transparency of the surface was assessed visually. The values obtained here were as follows:

TABLE-US-00003 Scattered Corundum from corundum roll applicator Sample (after 10 000 (after 10 000 Test pressings) pressings) Gloss level change*) −1 gloss point −4 gloss points measured (Initial value: 15 gloss points) Visual assessment of No noticeable change Clearly visible wear gloss level change at the corners of the press platens *)Gloss level was measured with a gloss level tester from Dr. Lange at a measurement angle of 60°, DIN EN 13 722: 2004-10