RU2331511C2 - Method and device to apply glue and curative components - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention pertains to method and device to apply glue and curative components of multicomponent glue system to wooden part surfaces. The problem is solved due to the fact, that the method consists in capability to apply glue mixture components to the parts either separately, or as a ready-to-use mixture with application device, which is produced to support the mentioned alternative modes. At that, the device contains at least two glue application units. At least one of them, designed to apply curative components, can be switched off. Besides, the device contains at least one unit, which is used to apply either glue components, or mixed curative and glue components. The multicomponent glue system must contain at least one of the following glue components: urea-formaldehyde resin (UF), melamine urea-formaldehyde resin (MUF), melamine urea-phenol-formaldehyde resin (MUPF), phenol-resorcinol-formaldehyde resin (PRF), resorcinol-formaldehyde resin (RF), phenol-formaldehyde resin (PF), polyvinyl acetat (PVAc).

EFFECT: avoiding disadvantages of certain technical solutions.

8 cl, 2 ex, 1 dwg

Description

The invention relates to a method and apparatus for applying adhesive and curing components of a multicomponent adhesive system on the surface of wooden parts. Numerous methods of applying glue to the surface of wooden parts are known.

DE 3834027 A1 relates to a method for applying ready-to-use glue to the surface of wooden parts. Ready-to-use glue, which already contains a mixed adhesive and hardening components, is kept circulating through a storage container, an injection head with a guide element, under which there is a device for feeding wooden parts, and through a pallet. It is applied to the surface of wooden parts in the form of a cast film.

In addition, separate application of adhesive and curing agent is known. DE 2416032 C3 describes a method for gluing wooden parts, in which a curable liquid plastic adhesive and a liquid curing agent are applied separately from one another to one of the surfaces to be joined and said surfaces are then pressed together. The glue and curing agent are applied in the form of relatively thick parallel strips using a strip dispenser and are joined together by compressing the surfaces to be bonded to each other.

In the solution described in DE 2820907 C3, the resin component and the curing agent (hardener) are also used separately on at least one suture surface in the form of separate bundles.

In addition, the prior art describes the separate application of a liquid two-component adhesive system on the surface of wooden parts, in which one of the two components is applied in the form of a cast film, and the other in the form of strips (DE 3834026 A1).

WO 99/67028 relates to the separate application of resin and curing components in the form of tows by spraying or by combining two application methods.

A device for applying a multicomponent adhesive system is described, for example, in WO 99/67027. The device contains at least two hollow elements, at least one element per component, which has a number of holes. The corresponding component is fed through holes in the form of bundles on a substrate, which is located under the hollow element. The holes can be oriented above the plane of application.

Although numerous methods and devices for applying multicomponent adhesive systems to wooden surfaces are disclosed in the prior art and are suitable for either separate application of the components or for applying the adhesive as a ready-to-use mixture, until now there has been no method and device that allows alternative applications of both ways. In particular, for reasons of flexibility and cost, there is a need for a solution that provides the ability to quickly and easily re-equip the production line from mixed to separate application of components and vice versa. To implement the method of applying a mixed adhesive solution or individual components, in each case, a prior art application device is required that is adapted to the application conditions. Typically, two methods cannot be used on the same production line. Otherwise, it would be necessary to constantly change the equipment used in the production process, which would be possible only with a significant expenditure of time and effort and corresponding losses in productivity.

Therefore, the objective of the present invention is to provide a method and device that can avoid the disadvantages of technical solutions of the prior art. In addition, the objective is to combine many application methods with each other in one application device in a favorable manner.

According to the invention, this problem is solved by the method of applying the adhesive and curing components of a multicomponent adhesive system to the surface of wooden parts using a coating device that is capable of alternatively applying the adhesive and curing components separately or as a ready-to-use mixture. The fact that it is possible to switch from one process to another without any problems according to the requirements of the production situation is favorable.

The multicomponent adhesive system contains at least two components, one adhesive and one curing component, and, if necessary, additional components, for example additives to the curing agent, which act as accelerators.

When the adhesive and hardening components are applied separately, the components are mixed during application onto wooden surfaces or at the beginning of a process in which the wooden parts to be glued are pressed together. This avoids the fact that the application device will become clogged with residues of cured adhesive and, therefore, experience operational problems, respectively, avoids the need for frequent cleaning of the device.

In the process of applying components mixed for direct use, the adhesive before use contains all the components required for its further use or curing, such as solvent, catalyst, hardener, additives and auxiliary agents, fillers. In the case of glue, ready for use, the drying time must meet certain requirements. On the one hand, the drying time should be long enough to avoid excessively quick drying of the adhesive applied to the wood surface, and to facilitate the processing of glued wooden parts for a certain required period of time. On the other hand, a very short compression time is desired after the press is closed. Therefore, the glue must quickly cure after the wooden parts to which the glue is applied are joined.

In the method according to the invention, the application device can alternatively be adjusted to apply the adhesive and curing components separately or mixed directly on the surface of the wooden parts. Both application methods are carried out on the same application device, depending on the choice. The choice of the appropriate application method depends, for example, on the wooden parts to be glued, in particular on their size and shape and on the adhesive and curing components used, in particular on the reactivity of the corresponding system. The user selects the appropriate optimal application method, as well as the adhesive and curing components used.

The application device is preferably a device for applying adhesive and curing components in the form of bundles or layers on wooden surfaces. In a preferred embodiment of the present invention, separate adhesive and curing components are applied to surfaces by casting a cord or film, or a combination thereof.

In the method of casting a cord, components in the form of parallel cords or bundles are applied to a wooden surface on which adhesive is to be applied. Cords and harnesses of components are usually applied next to each other. It is also possible to apply curing component strands matching the adhesive strands in order to avoid unwanted direct contact of a clean hardener and a wooden surface. Partial mixing of the separately applied components occurs due to contact and friction of the wooden plates coated with glue during the introduction of the part into the press frame. The proper mixing and subsequent curing of the binder occurs after the application of compression pressure.

In the film casting method, a cast film is obtained which completely covers the surface on which the adhesive is to be applied. This ensures the production of wooden parts that have a uniform layer of adhesive and curing components and can be used to produce glued wooden elements. A cast film of curing components can be applied to a cast film of adhesive components or vice versa. If the hardener contains components that can damage the wood surface, it is preferable to first apply a cast film of adhesive components directly to the surface of the wood parts, and then a cast film of curing components. It is also possible to coat the applied films of the adhesive and curing components with an additional adhesive coating, for example, in order to avoid the risk of damage to the wood by the acids contained in the hardener, as well as direct contact of the acidic hardener with the wood.

When combining the methods of casting a cord and a film, for example, first a cast film of adhesive components is applied to the wooden parts to be glued, and then bundles of curing components or vice versa.

In a preferred embodiment of the present invention, the adhesive and curing components in the ready-to-use mixture are applied to the wooden surfaces as an adhesive solution using methods using injection cords or films. Thus, either plaits or uniform layers of the adhesive / curing component mixture are applied to the surface of the wooden part.

The methods of the invention allow the use of various types of liquid adhesives. A possible two-component adhesive system applied by the method according to the invention is known from DE 19603988 A1.

The applied multicomponent adhesive system preferably contains at least one of the following adhesive components: urea-formaldehyde resin (UF), melamine-urea-formaldehyde resin (MUF), melamine-urea-phenol-formaldehyde resin (MUPF), phenol-resorcinol formaldehyde resin (PRF), resorcinol-formaldehyde resin (RF), phenol-formaldehyde resin (PF), polyvinyl acetate (PVAc) or other adhesive component commonly used in wood processing.

A further object of the present invention is a deposition apparatus for carrying out the method according to the invention, which comprises at least two deposition units, at least a first deposition unit which can be disconnected from operation, serving for applying curing components, and at least a second application unit for applying either adhesive components or mixed curing and adhesive components.

When the adhesive and curing components are applied separately, at least the first application unit is for applying the curing agents and at least the second application unit is for applying the adhesive components. In this case, at least the first application unit is not disconnected from operation. At least one assembly for applying the curing components is disconnected from operation if the adhesive and curing components are to be applied in the form of a ready-to-use mixture (adhesive mass). This mixture is then applied to wooden surfaces using at least one application unit, which is used to apply either clean adhesive components or a mixture.

The installation for the separate application of adhesive and curing components of the prior art can be modified into a new device for applying so that the site for applying the curing agent can be disconnected from work. This can be done using a control system. Then alternatively work with a mixed adhesive mass using a site for applying adhesive components. By appropriately managing the production situation (minimizing previous glue residues in the glue application unit of the device), intermediate cleaning, which is otherwise required, can be avoided, and thus the benefits of minimized glue residues in the separate application method can be maintained. For this purpose, the unit for applying the device for applying the adhesive component is stopped before switching to another product (adhesive components (crude resin) or adhesive solution (ready-to-use adhesive)) and a new product is introduced to the minimum possible amounts of the previous product without intermediate cleaning. Before stopping the operation of the device for a long time (for example, at night), the gluing process is preferably completed with adhesive components (crude resin) in the unit for applying the adhesive component and said adhesive components are circulated sufficiently by pumping over a period of time when the device is not in use so that there is no need to clean the device. When using a glue solution (ready-to-use glue), before the unit is stopped for a long time, it must be cleaned, because the residues are cured and can only be removed subsequently mechanically. In addition, exemption from such balances reduces costs, since there is no need to eliminate them.

Compared to the commonly used mixed adhesive solution processing, the use of both methods in a single installation provides advantages in terms of saving cleaning time, residual product and costs. Depending on the requirements of the production situation, one method can be easily switched to another. The adhesive solution is used if individual components having a higher reactivity do not allow drying of the manufactured wooden parts for a sufficiently long time. In the present invention, no cleaning is required after completion of the production process with the mixed adhesive solution, since the raw resin is preferably further processed in the same application unit, and the application unit is thus “washed” with the raw resin.

The present invention also relates to the application of a method of manufacturing wooden parts, which contain at least two separate parts glued with glue, and consist of wood or wood-based materials (for example, chipboards, MDF, OSB, etc. ), for example, for the production of solid glued wood. Massive glued wood made from glued wooden thin plates is generally known. Massive glued wood is used, for example, as a material for load-bearing parts in industrial, residential or public buildings. It has very high strength and rigidity combined with low weight, high dimensional stability and dimensional accuracy, and a high-quality surface. It can be made of any desired length, shape and profile. In the manufacturing process, thin wooden plates are coated with glue, laid one on top of the other and then pressed together. After the adhesive has cured, massive glued wood can be treated in the same way as solid wood.

The application device according to the invention is preferably used when a separate application method is used for the manufacture of standard glued wood parts, with at least one application unit for applying curing components and at least another application unit for separate application of adhesive components. Due to the short time spent in the air, processes with separate application of the components are mainly suitable for the manufacture of standard parts of limited dimensions from solid glued wood. Standard parts are manufactured in conventional quantities for assortment and individual orders.

In addition, the application device according to the invention is preferably used for the manufacture of (optionally curved) parts from solid glued wood using a mixed application method, wherein at least one application unit for applying the curing components is disconnected from operation and at least Another application unit is for applying mixed curing and adhesive components. The mixed method is most suitable for parts connected in a certain order, possibly having a more complex shape (building elements). The limiting factor is the drying time achieved with the separate use of the components, and therefore the number of linear meters of wooden sheets that must be coated with glue before reaching the drying time, which is the latest time after which the press must be closed. With mixed adhesive curing components, longer drying times can be achieved.

Examples of such building parts are gable roof beams or fish-shaped trusses. Moreover, the assembly process after applying the adhesive requires time, which may exceed the drying time of the separately applied adhesive / curing system. It is necessary to use a longer time of the mixing process. Large building structures can reach sizes up to several thousand meters of the length of wooden sheets on which glue must be applied.

Example 1

The proposed device is operated in a separate application of adhesive and curing components of a multicomponent adhesive system (see drawing). In this case, the adhesive component is supplied from the first reservoir (3) to the application unit (1), which serves for applying the adhesive components. The adhesive component is applied through the assembly to the surface of the wooden part. As the multicomponent adhesive system, melamine-urea-formaldehyde resin (MUF), for example of the type Kauramin 683, is used together with a corresponding liquid hardener, for example, of the type Kauramin 688.

The curing component of the multicomponent adhesive system, located in the second tank (5), is applied to the surface of the wooden part through the application unit (7), which serves to apply the curing components.

In order to constantly supply a sufficient amount of the adhesive component to the tank (3) and the curing component into the tank (5), a hopper (9) for glue can be connected to the specified tank (3), and a hopper (11) for the hardener can be connected to the tank (5).

To switch the operating mode of the device to applying the ready-to-use mixture, the reservoir (3) is unloaded to the minimum residual amount of glue. Then switch the first three-way valve (13), and the glue from the hopper (9) is fed into the mixer (15). As a result of switching the second three-way valve (17), the hardener located in the tank (5) is also fed into the mixer (15). The adhesive and curing components are mixed in the mixer (15) and the resulting mixture is fed into the tank (3). By pumping, the mixture obtained in the mixer is mixed with the residual amount of glue in the tank (3). The mixture thus obtained is applied through the application unit (1) to the surface of a wooden part.

Example 2

The proposed device is operated in the application mode of a ready-to-use mixture of a multicomponent adhesive system. In this case, the mixture from the first tank (3) is applied through the application unit (1) to the surface of the wooden part.

To switch the operation of the device to the separate application of adhesive and curing components of a multicomponent adhesive system, the reservoir (3) is unloaded to the minimum residual amount of the mixture. Then, the first three-way valve (13) is switched, and the glue from the hopper (9) is supplied to the reservoir (3), and then to the application unit (1). In addition, the second three-way valve (17) is switched in such a way that the hardener located in the tank (5) is supplied to the application unit (7). By pumping, the glue supplied from the tank (3) is mixed and the remaining amount of the ready-to-use mixture in the tank (3) is mixed. The mixture thus obtained in the tank (3) with a small amount of the hardener residual from the ready-to-use mixture is applied through the application unit (1) to the surface of the wooden part. Moreover, due to the constant addition of a clean adhesive component, the indicated small amount of hardener quickly decreases in the operating mode.

The curing component of the multicomponent adhesive system, located in the second tank (5), is pumped and through the application unit (7), which serves to apply the curing components, is applied to the surface of the wooden part.

In order to prevent clogging of the mixer (15) and pipelines from the mixer (15) to the tank (3), these elements are cleaned. This cleaning can be carried out during operation of the proposed device in a separate application of adhesive and curing components of a multicomponent adhesive system.

As a result of laboratory and production experiments, it was found that switching the operating modes of the proposed device is carried out without problems. In particular, it was found that the residual amount of hardener from the ready-to-use mixture does not adversely affect the processing of the adhesive component added to the tank (3).

Claims (8)

1. The method of applying adhesive and curing components of a multicomponent adhesive system to the surface of wooden parts using a device for applying, characterized in that the adhesive and curing components are applied separately or as a ready-to-use mixture by means of a device for applying, which is configured to implement these alternative modes, and the said device contains at least two nodes for applying at least one node for applying, which can be disabled n from work, serving for applying curing components, and at least another application unit, serving for applying either adhesive components or mixed curing and adhesive components, and the applied multicomponent adhesive system contains at least one of the following adhesive components: urea-formaldehyde resin (UF), melamine-urea-formaldehyde resin (MUF), melamine-urea-phenol-formaldehyde resin (MUPF), phenol-resorcinol-formaldehyde resin (PRF), resorcinol-formaldehyde resin (RF), phenol formaldehyde idnaya resin (PF), polyvinyl acetate (PVAc). 2. The method according to claim 1, characterized in that the individual adhesive and hardening components are applied to the surface by casting a cord or film or a combination thereof. 3. The method according to claim 1, characterized in that the adhesive and curing components in the form of a ready-to-use mixture are applied in the form of an adhesive solution by casting a cord or film. 4. The application device for implementing the method according to any one of claims 1 to 3, which contains at least two nodes for applying at least one node for applying, which can be disconnected from work, serving for applying curing components and at least another application unit for applying either adhesive components or mixed curing and adhesive components. 5. The application of the method according to any one of claims 1 to 3 for the manufacture of wooden parts that contain at least two separate parts connected by glue from wood or wood materials. 6. Application of the method according to any one of claims 1 to 3 for the manufacture of solid glued wood. 7. The application of the application device according to claim 4 for the manufacture of standard parts from solid glued wood, in which at least one application unit serves for applying curing components, and at least another application unit serves for separate application adhesive components. 8. The use of the application device according to claim 4 for the manufacture of building parts, in which at least one application unit for applying the curing components is disconnected from operation, and at least the other application unit serves for application mixed curing and adhesive components.