DE10349177A1 - Ennobling of panels in previously shaped softwood, by application on surface of one side of lamina, sheet or coating film, of adhesive gauze of Hot Melt type reactive polyurethane based solid, preheating, and coupling to softwood panel - Google Patents

Abstract

Ennobling of panels in previously shaped softwood (1), comprises application to semi-finished panel of coating by doctor knife or roller, on the surface of one side of a lamina, sheet or coating film (2), of the type in polymeric material or in natural or technical fabric, of an adhesive gauze of Hot Melt type 100% reactive polyurethane based solid; preheating of lamina, sheet or coating film; and coupling to softwood panel by hot pressing. Ennobling of panels in previously shaped softwood, comprises application to semi-finished panel of coating made up of a lamina, sheet or film at least of the polymeric type by application of an adhesive product. The method comprises application by doctor knife or roller, on the surface of one side of a lamina, sheet or a coating film, of the type in polymeric material or in natural or technical fabric, of an adhesive gauze of the Hot Melt type 100% reactive polyurethane based solid; positioning of the lamina, sheet or coating film on the corresponding surface of at least one side of the softwood panel; preheating of the lamina, sheet or the coating film; and coupling of the lamina, sheet or coating film to the softwood panel by hot pressing.

Description

SCOPE OF APPLICATION INVENTION

Object of the present invention is a finishing process for Wood chipboard or MDF boards.

The main change is if not exclusively, in the field of for Third manufactured semi-finished goods for the production of components used for furnishing furniture.

The increasingly strong demand, the forest stock to protect, has, together with the ever increasing timber prices, already for some time to fundamental changes in the conventional Manufacturing process of furnishing furniture contributed. Accordingly the processing of felled and then processed trees greatly reduced.

To reduce production costs, especially with regard to the rather inferior products the wood industry was therefore forced to find solutions looking to make one both aesthetic as well as appropriate wood replacement on a production level to find. The use of wood substitute panels is therefore in this production area common become. These plates generally consist of chips, respectively Wood flours or fibers with different granulometry mixed with adhesives based on synthetic resins and then in Plate form are compressed, the synthetic resins then through Hot presses are polymerized. It is obvious that yourself these panels, both because of the material from which they are made as well as the resulting inferior aesthetics, not suitable for being processed directly to produce a piece of furniture become. For this reason, it was considered necessary, just to clad and refine these panels to ensure a product to be able the same from the aesthetic Viewpoint is flawless.

The current state of the art is different Processing processes for finishing these plates known. The stake of these plates as well as their refinement is by at least two factors justified. On the one hand, the production costs significantly reduced while at the same time the possible Customer base increases, on the other hand, the structural characteristics enable this Plates of different processing and combinations, both what shapes and decorations of different kinds, as well as what the coloring concerns. A third advantage, but not always given is the fact that the base plate thanks to the application of a plastic coating, a longer shelf life is awarded, especially with regard to possible water infiltration and moisture in general, which kitchen furniture is particularly exposed to are.

STATE OF THE ART

The various can be used for information purposes only Systems under the more conventional examples for finishing a plate consisting of a coating material made of laminate, basically can be summarized in two categories.

A first system is only flat, raw elements made of wood chips or MDF, the retrospectively with one, two or four edges molded and coated on one or two flat sides, namely in subsequent and interchangeable phases (postforming and pressing).

A second system, however, works from flat elements, for example from wood chips or MDF that have already been refined with melamine paper and are can be suitable for bending or also not, and then later can be machined to a shaped using a sheet piling and grooving machine margins to obtain. This is the so-called preforming and softforming system.

Especially due to the fact that the treatments that these raw slabs of wood shavings or Be subjected to MDF, often Gravierfräsungen make necessary, which in turn changes the uniform flatness the surface different techniques have been developed with the goal of a finishing process with the greatest possible aesthetic Ensure result by applying a coating element.

As an example you can find in GB2297064 (Hoyle) the description of a process for the decorative finishing of the surfaces of strips or panels. The description contained in the above patent proposes a solution to the coating problem with the aid of a laminate which is attached to a groove which has been incorporated in a strip or in a plate which in turn is processed into a door for a piece of furniture. In this door, which can consist of a plate made of MDF, which is coated with a laminated surface, a groove is incorporated, which in turn describes a central part in relief. Mask paper is then placed on the surface of the side of the door into which the above groove has been incorporated and is then removed from the above groove. Thereafter, adhesive is applied to a film which, after being placed on the above-mentioned groove, is removed so that the adhesive on it remains in the groove. At this point, a PVC sheet is placed on the surface of the door, which is held in place by the adhesive previously inserted into the groove. The one Part of this PVC sheet, which protrudes above the fillet mentioned above, is then removed.

At the current time the ordinary Refinement process of a board made of wood substitute material in the application a laminate or a PVC or a polypropylene film or similar by sticking. In summary, it can be said that this finishing process a plate made of wood substitute material, especially from MDF, described as follows can be: After the plate is shaped accordingly, and should this desired be, in addition with the engraving milling machine has been processed, a first phase follows, during the same plate in a first workstation is introduced in which they are for the cold glue is treated. This cold glue preparation phase is an even layer of an adhesive, be it with a single component or with two Components to be applied to the surface of the plate, to which the laminate or the coating film is applied shall be. After completing this first phase is a second Phase provided during the plate is transferred to a drying station, in which the glue self contained water necessarily evaporated to allow the adhesive to adhere properly. After the drying phase of the adhesive layer is complete, it will see Type of processing then before that the plate is transferred to a third processing station, in which the coating film on the one previously provided with the adhesive surface the plate is applied. A final processing phase sees then before that the above plate and above, on it applied covering layer is subjected to a pressing process which is normally carried out with the help of a hot membrane press.

DISADVANTAGE

Despite the remarkable wealth of technological experience, to the present day in the field of machining coated Plates could be collected, some still exist insufficiently resolved Issues. The latter mainly relate to constant improvement the price / quality ratio, around which the prefabricated furniture companies constantly are trying and subsequently those companies that manufacture semi-finished products for third parties manufacturing, forcing to introduce innovative solutions. Either that described in GB2297064 (Hoyle) as well as that as more common Process for finishing wood chipboard and MDF boards described solution are unfortunately not free from certain restrictive aspects.

A first limitation is attributed to the fact that the plate used as a base, even if the fibers from which it is fine-grained have more or less rough surfaces. The underlying ones Fibers emerge easily and this phenomenon causes the coating film not entirely is just. This effect is particularly in the case of those made from wood shavings Plates very striking. Moreover limits this Roughness also the choice of coating material, which, particularly, if it’s plastic, it’s bound to be one Have strength that excludes the pause effect that occurs after gluing and pressing the laminate or the film onto the surface of the plate itself occurs. Even if you coat MDF boards, their disadvantages regarding the unevenness of the base material compared to those the chipboard are significantly more limited, so this is Disadvantage due to the usual finishing process described above considerably accentuated, since, based on the use of adhesives, by spraying be applied, an adhesion phase by means of aspersion of the appropriate adhesive onto the surface of the refining plate and a subsequent drying phase. These phases of the finishing process also have an effect remarkable emergence of the fibers with the adhesive in touch have come, which in turn makes it necessary for the process for finishing the plate laminates or films made of polymer to use which is a strength which also have this special surface effect consider.

A second restrictive Aspect seems to be given by the fact that in the above usual Finishing process a phase is necessary during which the plate for a predetermined Time period is loaded into a drying station so that the used Water contained in the adhesive can evaporate. Such a phase of the work process involving the storage of the treated panels For this provides for special purpose designated storage racks, via a Period of time that generally spans a few hours, has the disadvantage that it significantly increases the finishing process delayed and also the availability Requires premises specifically intended for storage.

Now what specifically in GB2297064 As far as (Hoyle) is concerned, the solution, although it relates to the finishing of the fluted parts of a panel, does not, according to the applicant, contain any notable improvements compared to the conventional finishing technique, but basically has the same limitations. In addition, the high number of processing phases necessary for the solution itself has negative effects both on the working time and on the consequent increase in industrialization costs and also brings with it a higher cost of materials and a more serious environmental impact, which is inevitable higher waste.

From these preliminary considerations clearly shows the need to find alternative solutions Find.

The aim of the present invention Accordingly, it also has the disadvantages described above to eliminate.

SUMMARY OF THE INVENTION

This and other goals are achieved through which correspond to the characteristics listed in the appended claims of the present invention achieved by those discussed Problems with the help of a process to refine previously formed and / or with the engraving milling machine processed wood chipboard or MDF boards are solved, the said working method stipulates a working cycle, which is divided into several phases and in which the cycle mentioned at least the execution of the phases described below:

• (a) Apply a layer of a solid adhesive Hot Melt 100%, based on reactive polyurethane with the help of a squeegee or roller, on one of the two surfaces one Laminates, a film or a film for coating, in particular made of polymer material or natural or technical Material;
• (b) laying on the laminate intended for coating, the film or the film on the corresponding surface of the plate to be finished;
• (c) preheating of the laminate or the film intended for coating or the film;
• (d) laminating the laminate intended for coating, the Foil or the film on the plate to be finished by hot pressing.

BENEFITS

That way, through that remarkable creativity, the effect of which is immediate represents technical progress, different advantageous Goals achieved.

A first goal is one Process for finishing wood panels, especially wood chips or MDF, to realize it, since there is none Spray phase of the adhesive and no phase for evaporating the in the adhesive self contained water needs, enables the production times shorten considerably and to limit the total cost of industrialization and Moreover to achieve a remarkable increase in production itself.

A second advantageous goal lies in realizing a finishing process that it through the application of solid hot melt type adhesives based on 100% on reactive polyurethane, allows the superficial Avoid the emergence of the fibers that make up the panel and accordingly, despite maintaining the strengths of those intended for coating Laminates or films, a visible improvement in aesthetic Finish Quality to reach the plate.

A third advantageous goal lies in the possibility after completing the phase of applying the adhesive to the Laminate or the film for finishing, the final lamination of the the above-mentioned laminate or the above-mentioned film with to delay the plate to be finished up to 36 hours.

There is a fourth advantageous goal in the possibility for finishing the panels also coatings made of natural or synthetic materials, and therefore the offer of the Furniture market to expand and the product with a higher added value to bring to the market.

A fifth goal was finished products manufacture the higher one Have heat resistance, around 100 ° C compared to today's 85 ° C.

A sixth goal was rationalize the production process; on the one hand through recovery of storage space that was previously necessary due to the waiting times of the panels on the other hand because there were no more rooms for the phase for spraying of the adhesive on the plates and the resulting Saving of special labor and space.

In conclusion, one can say that with significantly lower overall costs and environmental impact compared to previous solutions the production of a technologically good product is made possible.

These and other advantages result derive from the detailed description of a preferred below Realization with the help of attached schematic drawings, their execution details not as restrictive but are to be understood as purely exemplary.

SHORT DESCRIPTION THE DRAWINGS

The 1 Fig. 3 is a block diagram illustrating the finishing method according to the invention.

The 2 is a block diagram illustrating a variant of the finishing method according to the invention.

The 3 last but not least represents a view of the chipboard, in which the laminate serving as the coating or the film is partially peeled off.

DESCRIPTION SOME EMBODIMENTS

Also referring to the pictures, you can see that a process for finishing a wood chip or MDF board 1 which was previously shaped and / or engraved, provides for a machining cycle that is divided into several phases.

More specifically, during a first phase, phase (a) of the processing method on which the present invention is based, is applied to the underside of a laminate, film or film intended for coating 2 , in particular polymeric or made of technical fabric or natural material, superficially a layer of solid adhesive 3 of the type hot melt 100% distributed on the basis of reactive polyurethane. During this phase of the production process it is provided that the application of the layer of the adhesive 3 on the bottom 201 of the laminate, the film or the film intended for coating 2 with the help of at least one doctor blade or, depending on the special material from which the laminate or film 2 intended for coating is made, with the help of an application system with a hot roller.

The specific use of solid adhesives 3 Hot Melt type 100%, based on reactive polyurethane, which is actually used for purposes other than the finishing of chipboard and MDF 1 are surprisingly found, especially when firmly laminating a laminate, foil or film intended for coating 2 Made of polymer material or technical material, or natural material on a support made of a chipboard or MDF board 1 exists as being particularly suitable.

It was found in particular that in the case of a laminate or film intended for coating 2 polymeric type, the use of an adhesive application system 3 with the aid of a doctor blade is particularly advantageous, while in the case of laminates or films intended for coating 2 from technical material or from natural material the use of a system for applying the adhesive 3 with the help of a role has proven to be more advantageous. In both cases it was found that the operating temperatures of the adhesive 3 on the spreading head must lie between 80 and 140 centigrades ± 10%, depending on the different thickness and the different type of laminate, film or film intended for coating 2 that are currently being used.

More specifically, during the above-mentioned first phase, phase (a) of the finishing process, the use of the adhesives listed below has been used 3 proven to be particularly suitable:

• - Products FORBO RK99 / 51 or HENKEL DORUS 6202 for application rates from 20 to 50 grams per square meter, with application systems for the adhesive 3 of the type with a squeegee for laminates or films intended for coating 2 polymeric type;
• - Products BOSTIK-FINDLEY of the HPU series and in particular 51018 MHV for application rates from 20 to 50 grams per square meter, for use with laminates or films intended for coating 2 made from technical fabrics or from natural fabrics and with application systems for the adhesive 3 hot roll type.

After the first phase described above, phase (a) of the process, a second phase, phase (b), is provided during which the above-mentioned coating laminate or the above-mentioned coating film 2 that with the adhesive 3 was coated on the corresponding surface of the chipboard or MDF board to be finished 1 is positioned.

A third phase, phase (c) of the procedure, provides that the above-mentioned coating laminate or the above-mentioned coating film 2 on the corresponding surface of the chipboard or MDF board to be finished 1 positioned by preheating using appropriate means at temperatures between 80 and 95, ± 10% centigrad, for the purpose of thermoreactivating the adhesive 3 to effect.

A fourth and final phase, phase (d) of the procedure, provides for the definitive lamination of the laminate, the film or the film intended for coating 2 on the chipboard or MDF board 1 by the uniform application of a predetermined pressure on the surface of the laminate or film intended for coating 2 self; a pressure exerted in a thermostatic press for a period of 5 to 25 ± 10% seconds, while a transparent and micro-perforated polyester or polyethylene film of appropriate thickness between the solid press board and the wood chip or MDF board 1 is inserted.

During the last phase mentioned above, phase (d) of the process, the use of membrane presses has been found to be particularly suitable and that to keep the press board from excess adhesive 3 to protect, which emerges from the molds during the actual pressing phase, namely via the micro-perforated polyester or polyethylene film mentioned above, and in the event that the use of presses is provided which are not equipped with a light beam collimation system it is possible Use a soft cardboard or a sheet of crepe paper to put in between.

A variant of the process described here for finishing wood chipboard or MDF boards 1 looks after the completion of the first phase, phase (a), during which the layer of adhesive 3 to the bottom 201 of the laminate or film intended for coating 2 It is envisaged another phase before, phase (e), in the course of which on the same underside 201 of the above-mentioned laminate or film intended for coating 2 a silicone protective film is positioned by appropriate means. After that, at the latest within 36 hours after applying the adhesive 3 a further phase is then provided, phase (f), during which the above-mentioned silicone protective film is then removed again using appropriate means. After this removal, the phase already described, phase (b), follows for positioning the laminate or film or film intended for coating 2 on the chipboard or MDF board to be finished 1 , the phase for thermoreactivating the adhesive 3 , phase (c), and then the pressing phase, phase (d).

For an exemplary explanation are some examples of how to apply the method to the subject The present invention describes three different Consider types of coating / polymer film.

EXAMPLE 1

Refinement with polymer film

Here the product Forbo RK99 / 51 used with a doctor blade at 145 ° C in a ratio of 35gr / m2 is applied. The polymer carrier is a 22 micron thick slightly embossed PVC (polyvinyl chloride), from Alfaterm. The Use of the press preferably requires a water powered one Membrane press from Italpresse. The pressure exerted is 6 kg, while the application temperature 89 ° C is, with a press cycle of 10ö and after preheating the Films about 15ö.

EXAMPLE 2

Refinement with polymer film

In this case the product is Henkel Dorus 6202 applied with a doctor blade in a ratio of 30gr / m2 is applied. The polymer carrier is a 25 micron this time strong, shiny PVC (polyvinyl chloride), from Alfaterm. The use of the press preferably requires an air powered membrane press from the company Wemhon presses. The exercised Pressure is 8 kg, while the Application temperature 90 ° C is, with a press cycle of 20ö and after preheating of the film about 15ö.

EXAMPLE 3

Refinement with technical material

Here the product Bostik-Findley HPU51018MHV used with a roller at 90 ° C in a ratio of 40gr / m2 is applied. The polymer carrier is 2.5 mm thick Polyäthylenhartschaum. The use of the press preferably requires an oil-powered one Membrane press from Kolmag Carrozzauto. The pressure exerted is 6 kg, while the application temperature 80 ° C is, at a press cycle of 25e and after the film has been preheated to over 20o.

Claims (9)

Process for finishing preformed wood chips or MDF boards, including the application of a coating consisting of a laminate, a film or a film, at least polymeric in one Semi-finished plate by applying an adhesive, thereby characterized that to execute The following phases of a machining cycle are provided: (A) Apply a layer of Hot Melt 100% solid adhesive, based on reactive polyurethane by means of a squeegee or roller on the surface of a Side of a laminate, foil or film intended for coating, made of polymer material or technical or natural Material; (b) positioning of the laminate intended for coating, or the film or the film on the corresponding surface at least one side of the chipboard or MDF board; (C) preheat of the laminate intended for coating, or Foil or film; (d) laminating what is intended for coating Laminate, or the film or the film on the wood chip or MDF board, by hot pressing. Process for finishing pre-formed chipboard or MDF boards according to claim 1, characterized in that the phases listed below are provided for carrying out a processing cycle: (a) Applying a layer of solid hot-melt type adhesive 100%, based on reactive polyurethane , by means of a doctor blade or roller, on the surface of one side of a laminate intended for coating, or a film or film made of polymer material or made of technical or natural material; (e) positioning a silicone protective film on the surface of the laminate intended for coating, or the film or film on which the layer of adhesive has been applied; (f) removing the silicone protective film from the surface of the laminate intended for coating, or the film or film on which the layer of adhesive has been applied; (b) positioning the laminate or the film or film intended for coating on the corresponding surface of at least one side of the wood chipboard or MDF board; (c) preheating the laminate intended for coating, or the film or the film; (d) Definitive lamination of the laminate intended for coating, or of the film or film, onto the wood chipboard or MDF board by hot pressing. Process for finishing preformed wood chips or MDF boards according to the claims 1 and 2, characterized in that it applies to the applied Adhesives are the following products: - FORBO RK99 / 51 or - HENKEL DORUS 6202 or - BOSTIK FINDLEY of the HPU series and in particular 51018 MHV. Process for finishing preformed wood chips or MDF boards characterized according to the previous claims, that the application temperatures of the adhesive on the spreading head between 80 and 140, ± 10%, Centigrades. Process for finishing preformed wood chips respectively MDF boards according to the previous ones claims and characterized in that the above coating laminate or the above-mentioned coating film, which on the corresponding surface the plate to be refined has been preheated Temperatures between 80 and 95, ± 10%, subjected to centigrades becomes. Process for finishing preformed wood chips or MDF boards according to the previous claims, characterized in that pressing in a thermostatic press takes place, with a pressing time that between 5 and 25, ± 10% seconds can vary. Process for finishing preformed wood chips or MDF boards according to the previous claims, characterized in that the coating laminate, the coating film respectively the coating film is not only made of polymer, but technical or natural Is fabric. Process for finishing preformed wood chips or MDF boards according to the previous claims, characterized in that between the press board and the Coating laminate, the coating film or the Coating film at least one transparent polyester or Polyethylene film or a sheet of soft canon or crepe paper is inserted. Process for finishing preformed wood chips or MDF boards according to the previous claims, characterized in that the pressing is done by a membrane press.