Method and system for adhesive bonding of substrates

Abstract

Disclosed is a method for adhesively bonding substrates, which includes applying a layer of adhesive (1) to a first substrate and / or a second substrate, and disposing the first substrate on a second substrate with the applied layer of adhesive (1) disposed therebetween. The method further includes applying a radiation curing means (13) to the layer of adhesive (1) to selectively and partially cure the layer of adhesive (1) prior to disposing the first substrate on the second substrate.

Description

Technical Field

[0001] The object of the present invention is a method and system for adhesively joining substrates, where the substrates are formed by a coating support such as a panel or a profile material and a coating material such as a sheet or a laminate, both of which are adhered by an adhesive, and high quality in the surface finish of the adhesive product is provided. Such adhesive products include laminated panels or profile materials coated with sheets.

[0002] The method and system for adhesively joining substrates of the present invention are required particularly in products including substrates that require post-forming. Similarly, they are particularly required for transparent or similar coating materials having a high gloss such that defects in the application of the coating can be easily detected due to its characteristics.

[0003] The method and system for adhesively joining substrates of the present invention have applications in the manufacturing fields of architectural and furniture products such as furniture, panels for doors and floors, and profile materials for doors and window frames.

Background Art

[0004] In the industry for manufacturing laminated panels or coated profile materials, adhesives applied to the coating material and / or the substrate to be coated are usually used, and then the coating is attached to the panel or profile material.

[0005] The adhesive needs to be in a liquid state in order to effectively penetrate the substrate for coating, spreading, and smoothing. After application, the adhesive is solidified and cured (when this action can be utilized) to obtain the required adhesive strength. The curing of an adhesive or an adhesive agent is a process of internal cross-linking or polymerization of the adhesive. Solidification includes the use of physical methods such as its evaporation or temperature reduction to change the adhesive from a liquid state to a solid state.

[0006] Depending on the type of application, various types of adhesives are used. Currently, there are a wide variety of adhesives, and in all of them, it is essential to understand and consider specific parameters when selecting any adhesive.

[0007] One of these parameters is the viscosity of the adhesive, which is understood as a measure of the adhesive's resistance to deformation or its ability to flow. Viscosity is used to measure the resistance of the adhesive's particles to movement.

[0008] Another parameter to consider is the adhesiveness of the adhesive. Adhesion refers to the adhesive gripping force with external elements; in other words, the ability of the adhesive to "stick" to them. This is determined by factors such as the polarity of the molecules that make up the adhesive and the van der Waals forces.

[0009] Another parameter is internal cohesive force. This is the intermolecular force within the adhesive itself that holds the bonded adhesive particles together. A low internal cohesive force makes the adhesive more fluid, so it is closely related to viscosity.

[0010] Finally, there is the adhesive strength of the adhesive, which is the strength of the bond between the two substrates being bonded, as a culmination of all the parameters mentioned so far. The adhesive strength of a tack or adhesive is determined by the minimum values ​​of tackiness and internal cohesive force.

[0011] Similarly, it is important to note that adhesives have a characteristic called "open time." This is the maximum time that can be achieved between the liquid state (low viscosity) at the beginning of application and the intermediate point (higher viscosity) which is less liquid (for example, in the case of PVAc adhesives, due to the evaporation of a certain amount of water; in the case of thermoplastic adhesives, due to a decrease in temperature or as curing progresses). During this time, the adhesive is not considered to have deteriorated, and pre-bonding work can be carried out.

[0012] As already mentioned, different adhesives with varying parameter values ​​will be used depending on the specific bonding requirements.

[0013] In any bonding process, the initial internal cohesive force is very low because the adhesive is liquid (low viscosity). Therefore, for example, water-based wood glue "sucks in" (due to its tackiness) to the panel and the laminate to which it is bonded, but initially they are not tightly bonded and may separate before the adhesive dries (low internal cohesive force / viscosity). As the adhesive dries (or, in the case of adhesives applied while hot (such as hot melt), as it cools and / or hardens, i.e., polymerizes), its viscosity increases until it reaches a solid state and complete polymerization (if there is a polymerization mechanism), and therefore its internal cohesive force also increases. From the application of the adhesive until its complete solidification and complete hardening (if any), there may be an initial stage where the internal cohesive force is less than the tackiness of the adhesive. Once the adhesive solidifies and hardens (by evaporation, cooling, polymerization, etc., if applicable), the internal cohesive force becomes greater than the tackiness, and the weakest bond in the joint between the panel and the laminate becomes its tackiness.

[0014] In specific applications such as lamination and / or coating, there is a need for excellent ability to apply, diffuse, and / or smooth the adhesive very uniformly at the time of application or close to application, and on a certain surface or a part thereof, followed by high immediate adhesive strength at an appropriate time on these same surfaces or other surfaces or parts thereof.

[0015] In adhesives, these two characteristics do not occur simultaneously. When an adhesive is in a low viscosity state, it can diffuse / smooth very well, but on the other hand, while the surface to which the adhesive is applied has adhesive properties (tackiness), it does not have strong internal cohesive force until its viscosity increases. Conversely, in adhesives with a certain degree of tackiness and high internal cohesive force (high viscosity), the adhesive cannot diffuse / smooth easily.

[0016] The need arises to allow for the "free selection" of adhesives having these characteristics, because certain coating panels and / or coating profiles that may be post-molded must be manufactured without defects, at least on their large surface areas, that are found precisely in the application of the adhesive located beneath the coating. Some coatings better "hide" or make these adhesive defects less visible. Others, however, are very "sensitive" to any adhesive defects, in other words, they make the underlying defects visible. They are "transparent" to what lies beneath them, and sometimes even amplify and strengthen it. This is the case, for example, with coatings made of glossy materials (materials with a mirror-like surface finish) or transparent materials.

[0017] Therefore, for example, in the lamination (process for manufacturing laminated panels) or coating (process for manufacturing coated profile materials) of a substrate having a coating sheet or laminate that is highly glossy or transparent, any defects in the application and / or smoothing of adhesive to the large or translucent surface(s) of the substrate are very easily visible.

[0018] There are various types of defects. The most common are "structuring of the adhesive," "band-like application of the adhesive," and "air bubbles" that appear between the substrate and the coating material. Next, we will briefly explain what these defects are.

[0019] - Structuring of adhesives This is a defect that arises solely from the fact that an adhesive is applied to a surface by a certain application system, due to the viscosity of the adhesive, the relative velocities of the different elements involved (adhesive, application element, and the element being applied to), and the influence of the surface tension of those elements.

[0020] When adhesive is applied to a panel or coating material by a roller (see Figure 1), the adhesive comes into contact with the material at the application point (P), creating a contact surface (C) between the material and the applied layer of adhesive. At this contact surface (C), the adhesive is initially fixed to the material by capillary action, but the top surface (S) of the adhesive layer is also initially adhered to the application roller by capillary force. At the contact surface (C) between the adhesive and the material to which it is applied, the adhesive layer becomes the velocity of the material (which is usually moved by a roller, conveyor belt, or other means of transport), while the top surface (S) of the adhesive layer still maintains the same velocity as the roller. However, because the capillary force fixing the adhesive to the roller is less than the capillary force adhering the adhesive to the material to which it is applied (the material on which the application roller is made is non-adhesive), the top surface (S) of the adhesive tries to move in the direction given by the roller, separating from the roller and creating a peak / valley structure. This process is repeated throughout the duration that the adhesive is applied to the material.

[0021] The above defects become more pronounced with increasing amounts of adhesive applied. This is because, although the capillary force at the contact surface (C) is greater than the capillary force at the top surface (S), the internal cohesive force is still somewhat weak in the initial stages of bonding, allowing the top surface (S) to stretch further until it separates from the roller, thus forming high peaks / valleys.

[0022] Furthermore, the aforementioned defect of "peak / valley" structuring is exacerbated when the applied adhesive has a higher viscosity. This is because a higher viscosity adhesive reduces its fluidity, thus decreasing its ability to "auto-smooth" after application and causing the adhesive to set more quickly.

[0023] Defects in the formation of this "peak / valley" structure become apparent after a certain covering material is applied, resulting in what is known as "orange peel."

[0024] Furthermore, when the application of the adhesive to the substrate is performed by an application "lip", since the lip is a static element, the structuring effect of the adhesive is lower than in the case of roller application. In the case of application by a lip, the appearance of "line" defects due to insufficient adhesive caused by clogging of the application groove (the outlet of the nozzle) of the lip by impurities, crosslinked adhesive, etc. is more common.

[0025] Adhesive defects and structural defects are usually corrected by smoothing the adhesive after application. In certain applications, when smoothing cannot be performed due to viscosity reasons, or when there is simply no smoothing in the process, as already explained, the likelihood of adhesive structuring is higher when there is more adhesive than when there is less.

[0026] - Strip application of adhesive : It consists of the strip-like appearance of the adhesive on the panel or coating (depending on the substrate to which the adhesive is applied), and the strip has a higher or lower weight per unit area perpendicular to the longitudinal direction of the forward movement of the panel or coating. This is caused by a lack of uniformity in the continuity of the longitudinal forward movement due to interference occurring between different elements involved in the process, such as different deliveries, substrates, coating elements, coil brakes, etc. If the viscosity of the adhesive is high, these defects appear more clearly, while if the viscosity is low, it conforms better. This appears as the so-called "fishbone effect" in the final product.

[0027] - bubbles : This defect consists of air bubbles appearing between the coating material and the adhesive or between the panel and the adhesive (depending on the substrate to which the adhesive is first applied). This defect mainly appears in hard coating materials.

[0028] Currently, what is being done is to use the minimum amount of adhesive that provides sufficient internal cohesion to integrally bond and hold the substrates during the placement of the substrates and, if necessary, during post-forming, so as to appropriately fix the coating to the substrate while having as low a viscosity as possible in the applied state. These viscosities do not allow for easy smoothing of these adhesives after their application, but at least, particularly in the regions to be post-formed, they are made as low as possible as required, thereby reducing to the greatest extent possible the defects caused by excessive viscosity or the amount of the adhesive.

[0029] Another solution to this problem for these existing laminates and coatings in the art is to apply different adhesives having different viscosities (and thus different degrees of internal cohesion) to different regions as required (for example, regions of the substrate that are to be post-formed and thus subject to large mechanical stresses, and regions of the substrate that are not post-formed and thus subject to smaller mechanical stresses). This solution has several drawbacks, such as having to apply different adhesives using multiple dispensers and the complexity of defining the application so as to avoid problems (interferences) in the boundary regions between the different application regions of the different adhesives.

Summary of the Invention

Problems to be Solved by the Invention

[0030] Existing solutions in the prior art have not been able to reduce the above problems in a satisfactory manner and, at the same time, guarantee that the substrates are strongly adhered to each other, for example, in the post-forming region.

[0031] The present invention relates to a method and system for adhesively joining substrates to solve the above drawbacks.

Means for Solving the Problems

[0033] The new method involves applying radiation curing means to the adhesive layer in order to selectively partially cure the adhesive layer, and the selective and partial curing is performed before the first substrate is placed on the second substrate.

[0034] According to the present invention, selective and partial curing is performed by a curing means prior to placement. In the context of the present invention, selective and partial curing is understood as curing performed to a selected or predetermined degree of curing without resulting in complete or finished curing prior to placement. That is, for example, an adhesive layer can be cured to at least 50%, preferably at least 75%, prior to placement, which corresponds to the degree of polymerization achieved in proportion to the complete polymerization of the adhesive layer material being at least 50% or 75%, respectively. A higher degree of curing or polymerization promotes an increase in the viscosity of the adhesive layer, and therefore its internal cohesive force. In this way, it is possible to provide suitable internal cohesive force by increasing the viscosity of the adhesive layer with adhesive strength suitable for bonding substrates without impairing the required tackiness (unlike what happens when attempting to increase viscosity by changing the medium that gives the adhesive its liquid state, for example, by evaporating water in wood glue or PVAc, or by lowering the temperature in thermoplastic adhesives (where tackiness is impaired)).

[0035] The curing method is applied by radiation. In other words, the adhesive used is configured so that its curing or polymerization occurs upon application of radiation. Radiation allows for the effective application of curing energy to achieve sufficiently fast or accelerated curing, corresponding to the typical time required for industrial processes, particularly for bonding coating materials such as continuous laminates or sheets to coating supports such as panels or profile materials, for the arrangement of the substrates to be bonded. These process times can be as short as a few seconds.

[0036] According to the present invention, any type of radiation can be used to cure the adhesive used. Preferably, curing can be done by electromagnetic radiation such as UV or IR, or by particle beam using electrons (EB, "electron beam").

[0037] According to the present invention, after the placement of the substrate, the curing of the adhesive layer can also be completed, for example, by applying radiation that can pass through the coated substrate.

[0038] Advantageously, compared to conventional adhesive bonding methods that use adhesives with slow curing mechanisms, such as PUR (polyurethane), which react with moisture in the air (taking several hours or even several days), the present invention makes it possible to provide appropriate viscosity in a selectable manner before placement without impairing tackiness and adhesive strength with the substrate.

[0039] Thus, unlike conventional techniques in which viscosity is increased by, for example, cooling the adhesive before placement (which impairs tackiness) in the case of thermoplastic adhesives to increase internal cohesive force, or adhesives that have high initial viscosity and appropriate tackiness to provide high internal cohesive force at placement, the present invention provides versatility to adhesive bonding methods by enabling the use of various adhesives to achieve sufficient internal cohesive force in a controlled manner. Radiation allows for accelerated curing in a controlled manner to increase internal cohesive force before placement without impairing tackiness and adhesive strength.

[0040] Furthermore, the adhesive may have additional curing mechanisms, particularly those that can be activated before and / or after placement. For example, a PUR adhesive having a dual curing mechanism with additional curing by reaction with moisture can be used. An example of such an adhesive is commercially available from Henkel under the trade name "Dual Curing". For the purposes of the present invention, any other adhesive having an additional curing mechanism can be used. In this regard, for example, curing by mixing an additional component (e.g., water) with the adhesive, or curing by evaporation, can be used.

[0041] Possible radiation curing methods include, for example, the use of radiation-emitting lamps such as ultraviolet, LED, or electric arc discharge lamps, infrared lamps, and NIR. Additional curing methods include, for example, the use of humidifiers and evaporators.

[0042] Preferably, the process of the present invention includes post-forming at least one strip portion of the first substrate into at least one contour of the second substrate by post-forming means in order to place the first substrate on the second substrate.

[0043] According to possible embodiments, the adhesive bonding method of the present invention includes applying a curing means to an adhesive layer corresponding to a strip portion before (and / or during) post-molding of at least one strip portion of a first substrate to at least one contour of a second substrate.

[0044] "Post-molding" is understood as a series of operations in which, in the initial simple placement of the first substrate onto the second substrate, the first substrate is molded, adapted, or joined to the shape of the second substrate so that the first substrate covers the second substrate in strip-like portions, sections, or contours of the second substrate that were not covered by the first substrate.

[0045] The described method makes it possible to significantly increase the adhesive strength of the first substrate in the post-molded strip portions. This is particularly useful considering that, due to its elastic properties and / or shape memory, the first substrate may have a strong tendency to peel away from the second substrate at their post-molded contours.

[0046] Therefore, especially in post-molding regions / strip sections, there is no need to use different adhesives / sealants, and the adhesive can be applied with very low viscosity, which minimizes smoothing, or at least the effects of application, and this does not raise concerns about low adhesive strength, especially in post-molding regions, since the adhesive / sealant is exposed to the curing means.

[0047] This feature can be "fulfilled" by two factors that interfere with the curing of the adhesive, namely the curing ability of the curing means and the time elapsed between the application of the curing means and the placement of the first substrate onto the second substrate, so that the adhesive strength of the adhesive is enhanced, especially at the time of post-molding.

[0048] This method allows for easy application of curing means in both the regions that are post-molded and the regions that are not post-molded.

[0049] According to possible embodiments, a method for adhesive bonding of substrates includes post-forming a plurality of different strip-shaped portions of a first substrate into a plurality of different contours of a second substrate in a plurality of steps using a post-forming means.

[0050] In such circumstances, the method of the present invention may include at least a second application of a curing means between the two steps of post-molding.

[0051] This feature allows the curing means to be applied immediately before the post-molding of each strip portion of the first substrate to be post-molded, and therefore, ideal adhesive strength can be achieved in each post-molded strip portion at an ideal time, i.e., immediately before the post-molding operation of the strip portion.

[0052] As described above, according to possible embodiments, a method for adhesive bonding of substrates includes applying a curing means to a first strip portion of a first substrate that is not post-molded, in particular in combination with at least one strip portion of a first substrate that is post-molded.

[0053] This feature allows the strip portion of the first substrate, which is not post-molded, to be fixed very firmly to the second substrate, thereby preventing relative movement between the first and second substrates when the post-molded strip portion strongly pulls on the non-post-molded strip portion placed on the second substrate.

[0054] By applying the different types of curing methods described above, the adhesive strength of the adhesive can be enhanced to varying degrees and / or adapted to various types of adhesives that can be used.

[0055] Preferably, the adhesive bonding method of the present invention includes smoothing the adhesive layer (in whole or in part) immediately after its application to the first and / or second substrates. In this way, the finish of the first substrate after it has been placed on or post-molded onto the second substrate is improved, and the appearance and / or perception of defects caused precisely by the application of the adhesive, for example, the structuring of the adhesive layer, can be prevented.

[0056] According to a possible embodiment of the adhesive bonding method for substrates, the first substrate is a coating material, and the second substrate is a coating support on which the coating material is placed. The coating support may be, for example, in the form of a profile or a panel. The coating material may be, for example, in the form of a sheet or a laminate.

[0057] According to the adhesive bonding method of the present invention, adhesive bonded products such as laminated panels and coated profile materials can be obtained. The present invention is applicable, for example, to wood panels, aggregates, HDF, MDF, aluminum plates, iron or plastic, wood profile materials, HDF, MDF, PVC, aluminum, and the like.

[0058] A panel is understood as a product having a substantially flat shape, with relatively large width and length (usually longer than width), and a constant thickness. A profile is understood as a product having a rectangular shape, with its maximum dimension being length, and similar thickness and width. A laminated panel is understood as a covered panel, which can be post-formed if it is flat or if its edges are also covered in addition to a substantially flat surface. In covered profile materials, the covering is generally post-formed.

[0059] The present invention relates to an adhesive bonding system for substrates, and is applicable to substrates in which the first substrate is a coating material, particularly a laminate, and the second substrate is a coating support, particularly a panel, wherein the coating material is placed on the surface of the coating support.

[0060] The adhesive bonding system for the substrate includes a coating means for applying an adhesive layer to the covering material and / or covering support, and a placement means for positioning the covering material on the covering support.

[0061] The placement means can be formed by at least one roller for placing the covering laminate, thereby placing the sheet on the support when it is pressed against the support by the placement roller.

[0062] In the new method, the substrate bonding system of the present invention includes a radiation curing means for partially curing the adhesive layer, selectively positioned between an adhesive layer application means and a placement means.

[0063] Preferably, the adhesive bonding system for substrates of the present invention includes post-forming means for post-forming a coating material, particularly a laminate, onto at least one contour of a coating support, particularly a panel, wherein the system is configured to apply curing means to at least one strip of an adhesive layer corresponding to at least one strip of a coating material that is post-formed onto at least one contour of the coating support.

[0064] The placement means can be formed by at least one roller for post-forming the coating laminate, so that when the sheet is pressed against the support by the post-forming roller, the sheet is post-formed onto the support.

[0065] Similarly, preferably, the adhesive bonding system for substrates of the present invention is configured to carry out the adhesive bonding method for substrates described above.

[0066] The present invention also relates to an adhesive bonded product obtained according to the method described above. In particular, the adhesive bonded product comprises a first substrate which is a covering sheet and a second substrate which is a covering support on which the covering sheet is placed, and these substrates are bonded together according to the method described above. [Brief explanation of the drawing]

[0067] The following figures are included as part of the description of at least one embodiment of the present invention. [Figure 1] This diagram shows a schematic representation of the peak and valley structure of the adhesive layer applied to a covering sheet or panel by an application roller. [Figure 2a] This illustrates a substrate adhesive bonding system with post-molding of an assembly formed by panels and a covering sheet, in which adhesive is applied to a continuous covering sheet by an application roller, followed by a step of smoothing the adhesive layer on the covering sheet. [Figure 2b] This shows an adhesive bonding system similar to that in Figure 2a, but without the step of smoothing the adhesive layer of the covering sheet after application. [Figure 3a] This illustrates a substrate adhesive bonding system with post-molding of an assembly formed by a panel and a covering sheet, in which adhesive is applied to the covering sheet by a lip, and there is a subsequent step of smoothing the adhesive layer on the covering sheet. [Figure 3b] This shows an adhesive bonding system similar to that shown in Figure 3, but without the step of smoothing the adhesive layer of the covering sheet after application. [Figure 4]This illustrates a substrate adhesive bonding system involving post-molding of an assembly formed by a panel and a covering sheet, where the adhesive is applied to the covering sheet by a spray nozzle. [Figure 5] Figure 3b shows an adhesive bonding system for a substrate similar to that shown here, but with a curing means inserted between different post-molding means. [Figure 6] A schematic diagram of the cross-section of the covering sheet is shown. [Figure 7] A schematic diagram of the cross-section of the panel on which the covering sheet is placed is shown. [Figure 8] A schematic diagram of a cross-section of a coated sheet with an unsmoothed applied adhesive layer is shown. [Figure 9] A schematic diagram of a cross-section of a coated sheet with a smoothed adhesive layer is shown. [Figure 10a] A schematic diagram shows the use of a curing means for curing the adhesive at the two end strips of the adhesive layer applied to a covering sheet. [Figure 10b] Figure 10a shows a schematic diagram of the covering sheet, with two end strips in an advanced curing state. The covering sheet is placed on the panel via an adhesive layer before post-molding of the assembly formed by the panel and the covering sheet. [Figure 10c] Figure 10b shows a schematic diagram of the assembly of the panel and covering sheet after post-molding. [Figure 11a] A schematic diagram is shown illustrating the use of a curing means to cure the entire adhesive layer applied to a covering sheet. [Figure 11b] Figure 11a is a schematic diagram of the covering sheet, where the entire adhesive layer is in a partially cured state, and the covering sheet is placed on the panel via the adhesive layer before post-molding of the assembly formed by the panel and the covering sheet. [Figure 11c] Figure 11b shows a schematic diagram of the assembly of the panel and covering sheet after post-molding. [Figure 12]Figure 5 shows a schematic diagram of the cross-section HH, where the first application of the curing means for curing the adhesive is seen in the first strip-shaped portion of the adhesive layer deposited on the covering sheet, and the first strip-shaped portion of the adhesive layer corresponds to the first strip-shaped portion of the covering sheet that is not post-molded after placement on the panel. [Figure 13] Figure 5 is a schematic diagram of section II, where the second application of the curing means for curing the adhesive is seen in two second strip-shaped portions of the adhesive layer deposited on the covering sheet, and these two second strip-shaped portions of the adhesive layer correspond to second strip-shaped portions of the covering sheet that are post-molded after the covering sheet is placed on the panel. [Figure 14] Figure 5 is a schematic diagram of the cross-section JJ, where the third application of the curing means for curing the adhesive is seen in the third strip-shaped portion of the adhesive layer deposited on the covering sheet, and the third strip-shaped portion of the adhesive layer corresponds to the third strip-shaped portion of the covering sheet that is post-formed after the post-formation of the second strip-shaped portion of the covering sheet. [Figure 15] Figure 5 is a schematic diagram of the cross-section KK, where the fourth application of the curing means for curing the adhesive is seen in the fourth strip-shaped portion of the adhesive layer deposited on the covering sheet, and the fourth end strip-shaped portion of the adhesive layer corresponds to the fourth end strip-shaped portion of the covering sheet which is post-formed after the post-forming of the third strip-shaped portion of the covering sheet. [Figure 16] Figure 5 shows a schematic diagram of the cross-section LL, illustrating the assembly formed by the panel and the covering sheet after the fourth end strip portion of the covering sheet has been post-molded. [Figure 17] This illustrates a substrate adhesive bonding system involving post-molding of an assembly formed by a panel and a continuous covering sheet, wherein adhesive is applied to a continuous covering sheet by a lip and to a panel by an application roller, and then the adhesive layer on the panel is smoothed. [Figure 18] This illustrates a post-molding-free adhesive bonding system where adhesive is applied to the panel by an application roller, and then the adhesive layer on the panel is smoothed, forming an assembly with a panel and a continuous covering sheet. [Figure 19]This illustrates a non-post-molding adhesive bonding system for substrates formed by a panel and a discontinuous covering sheet, where adhesive is applied to the panel by an application roller, and then the adhesive layer on the panel is smoothed. [Figure 20a] A schematic diagram of a cross-section of a panel with an unsmoothed applied adhesive layer is shown. [Figure 20b] A schematic diagram of a cross-section of a panel with a coated and smoothed adhesive layer is shown. [Figure 20c] A schematic diagram of a cross-section of a panel with a hardened applied adhesive layer is shown. [Figure 21a] A schematic diagram of a cross-section of a coated sheet with an unsmoothed applied adhesive layer is shown. [Figure 21b] A schematic diagram of a cross-section of a coated sheet with a smoothed adhesive layer is shown. [Figure 21c] A schematic diagram of a cross-section of a coated sheet with a hardened adhesive layer is shown. [Figure 22] A schematic diagram of a joined panel and covering assembly without post-molding is shown. [Modes for carrying out the invention]

[0068] As described above, the present invention relates to a method and system for adhesive bonding of substrates.

[0069] In particular, to prevent the above-mentioned drawbacks regarding the structuring of the adhesive (1) (see Figure 1), the system and method of the present invention consider that the adhesive (1) can be applied at a viscosity low enough that its application does not cause defects, or that efficient smoothing after application is possible, or, in the absence of smoothing means, that automatic smoothing of the adhesive layer (1) is possible before the curing process progresses too far and the viscosity of the adhesive (1) increases, which hinders subsequent smoothing or automatic smoothing of the adhesive layer (1).

[0070] Therefore, according to the present invention, the applied adhesive (1) is partially cured by the radiation curing means (13) before the substrate is placed. The adhesive (1) used in the embodiments described below has a double curing mechanism, the additional curing mechanism being a reaction with moisture, so that when the substrate is placed, the adhesive (1) is fully cured by a reaction with moisture in the air (which can pass through to the placed substrate or base substrate up to the adhesive layer in between). An example of this type of adhesive is the moisture-reactive PUR adhesive, commercially available from Henkel under the trade name "Dual Curing".

[0071] The use of this type of adhesive (1) or substrate, as described later, does not limit the present invention. Therefore, for example, according to the present invention, if the placed substrate is transparent or semi-transparent to its radiation, it is assumed that the complete curing of the adhesive layer (1) can also be achieved by radiation, particularly UV electromagnetic radiation, after the placement of the substrate.

[0072] Figures 2a and 3a show two embodiments of a laminated panel manufacturing system with post-molding according to the present invention, in which a smoothing roller (7) is considered to be present after the application of adhesive (1) by a coating roller (4) and an additive roller (5) (Figure 2a) or lip (6) (Figure 3a).

[0073] Figures 2b and 3b show two embodiments of a system for manufacturing a laminated panel with post-molding according to the present invention, which are similar to those in Figures 2a and 3a, respectively, but in these embodiments, smoothing is not assumed after applying the adhesive layer (1) to the coating sheet (2).

[0074] Figure 4 shows an embodiment of the adhesive bonding system for substrates with post-molding, similar to that in Figure 2b, according to the present invention, but the adhesive layer (1) is applied by an adhesive spray nozzle (15) instead of an application roller (4).

[0075] In these figures above, the forward direction of the covering sheet (2) and panel (3) is indicated by arrows along the adhesive bonding system of the substrate with post-molding, as is the direction of rotation of the rollers.

[0076] In particular, in all systems for adhesive bonding of substrates with post-molding shown in these figures, whether or not there is a smoothing roller (7), there is a placement roller (9) for post-molding the coating sheet (2) on the panel (3). This placement roller (9) can also perform a certain smoothing function on the adhesive layer (1) located between the coating sheet (2) and the panel (3) by applying pressure to the coating sheet (2) (and therefore the adhesive layer (1)) on the panel (3).

[0077] Nevertheless, considering that the placement roller (9) acts some time after the adhesive layer (1) is applied to the covering sheet (2), it is desirable that the smoothing or automatic smoothing action of the adhesive layer (1) be started earlier than the time of application to the covering sheet (2). For this reason, it is desirable to prepare an adhesive (1) with very low viscosity at the time of application to the covering sheet (2). The same applies when it is applied to the panel (3) or both.

[0078] In all of the systems for adhesive bonding of substrates with post-forming shown in these figures, there is also a guide roller (10) which ensures that the covering sheet (2) is maintained in its path from the coil (11) to the panel (3).

[0079] In adhesive bonding systems for substrates involving post-forming, after the placement of the covering sheets (2) on the panel (3), it is necessary to perform post-forming operations to bond and conform the covering sheets (2) to the shape of the contour (14) of the panel (3) at their cross-sections or strip portions, as needed. To accomplish this, there are post-forming means (12) (typically consisting of post-forming rollers (8) and / or presses) that conform the covering sheets (2) to the specific shapes of each cross-section, strip portion, or contour (14) of the panel (3) after the placement of the covering sheets (2) on the panel (3).

[0080] As already mentioned, it is important that the adhesive (1) forming the adhesive layer (1) has the appropriate viscosity and internal cohesive force at the appropriate time. This is particularly important during post-forming operations because the post-forming operation is usually the narrow cross-section or strip portion of the covering sheet (2) that must cover the narrow cross-section or contour (14) of the panel (3), and the elastic force exerted by the covering sheet (2) to try to restore its stretched shape (before post-forming) is very strong, and therefore the adhesive (1) needs to have high adhesive strength at the exact moment the post-forming operation is performed.

[0081] For this reason, the adhesive bonding method for substrates of the present invention is expected to involve applying a curing means (13) to the corresponding strip portions of the adhesive layer (1) located on the corresponding strip portions of the covering sheet (2), which are post-molded to conform to the corresponding strip portions, cross sections, or contours (14) of the panel (3).

[0082] The curing means (13) may include means for emitting infrared (IR, NIR) radiation, ultraviolet (UV) radiation, or other types of radiation. These curing means are configured to selectively partially cure the adhesive and allow the application of selected radiation energy to the adhesive layer.

[0083] Therefore, in Figures 2a, 2b, 3a, 3b, 4 and 5, the application of the curing means (13) for the adhesive layer (1) is seen immediately after the adhesive layer (1) has been applied to the covering sheet (2) and before the covering sheet (2) has been aligned with the panel (3) and post-molded. These curing means (13) can be applied to the entire or specific strip portion of the adhesive layer (1) located on a particular strip portion of the covering sheet (2) that will be post-molded to the corresponding strip portion, cross section or contour (14) of the panel (3). In this way, the curing action of the adhesive layer (1) on the post-molded strip portion accelerates the application of the adhesive layer (1) to its strip portion or contour (14) so ​​that it has ideal viscosity and internal cohesive force properties that allow the covering sheet (2) to remain completely adhered to the panel (3) on its strip portion or contour (14) without detaching from the panel (3) and recovering its initial shape when the post-molding work must be performed.

[0084] Similarly, Figure 5 shows a modified example of a substrate adhesive bonding system with post-forming for implementing an embodiment of the substrate adhesive bonding method, in which the curing means (13) is inserted and applied between the successive applications of the covering sheet (2) and panel (3) by the post-forming means (12). In this way, the curing of the adhesive layer (1) in the corresponding strip portions to be post-formed in each post-forming step is accelerated immediately and precisely, just before the post-forming of each corresponding strip portion.

[0085] Figure 6 shows a cross-sectional view of the covering sheet (2) before the application of the adhesive layer (1), corresponding to, for example, the cross-section GG shown in Figures 2a and 2b.

[0086] Figure 7 shows a cross-sectional view of the panel (3) before the placement of the covering sheet (2), i.e., a view corresponding to the cross-sectional FF shown in Figures 2a and 2b, for example. The contour (14) of the panel (3) is shown, to which the covering sheet (2) must subsequently be joined by one or more post-forming operations.

[0087] Figure 8 is a cross-sectional view of a coating sheet (2) to which an adhesive layer (1) has been applied immediately prior to the application of adhesive. Due to the absence of smoothing or auto-smoothing action, the structure of the adhesive layer (1) can be seen, which forms peaks, valleys, or other defects. This figure corresponds, for example, to cross-section AA shown in Figure 2a.

[0088] Figure 9 shows a cross-sectional view of the covering sheet (2), where the adhesive layer (1) has already been smoothed, automatically flattened, or applied without defects. This figure corresponds to the cross-section BB shown in, for example, Figures 2a, 2b, 3a, 3b, 4, and 5.

[0089] Figure 10a shows a cross-sectional view of the covering sheet (2) and the adhesive layer (1), where the application of the curing means (13) to the two end strip portions (2') of the adhesive layer (1) can be seen. This figure corresponds to the cross-sectional CC shown in Figures 2a, 2b, 3a, 3b and 4, for example.

[0090] The portion or strip of the adhesive layer (1) exposed to the curing means (13) is shown in darker colors in the figure, in contrast to the portion of the adhesive layer not exposed to the curing means (13).

[0091] Figure 10b shows the arrangement of the covering sheet (2) in panel (3) as shown in Figure 10a. This figure corresponds to the section DD shown in Figures 2a, 2b, 3a, 3b and 4, for example. Panel (3) shows the right-hand contour (14) with a curved and complex shape compared to the other contour (14) at the left end, which has a simple and linear shape.

[0092] Figure 10c shows the covering sheet (2) of Figure 10b after post-molding of the end strip portion (2') at the contour (14) of the panel (3). This figure corresponds to the cross section EE shown in Figures 2a, 2b, 3a, 3b and 4, for example.

[0093] Figures 11a, 11b, and 11c show diagrams and cross-sections similar to those in Figures 10a, 10b, and 10c, respectively. However, in Figures 11a, 11b, and 11c, the curing means (13) is applied to the entire adhesive layer (13) and not to specific strip-shaped portions.

[0094] The present invention also envisions applying the curing means (13) to the entire surface of the adhesive layer (1), but to different degrees depending on the different strip-shaped portions of the adhesive layer (1). This allows for different degrees of viscosity and internal cohesive force to be obtained in different strip-shaped portions of the adhesive layer (1), depending on whether or not post-molding is required on the strip-shaped portion of the adhesive layer (1), or depending on the severity of the post-molding. Severity is understood as the complex, closed, or angular nature of the shape of the contour (14) of the panel (3) to be covered. The more complex, closed, or angular this shape, the greater the tendency of the covered sheet (2) to recover its initial shape, and therefore it is more important that the adhesive layer (1) in that strip-shaped portion has greater adhesive strength.

[0095] It is worth mentioning that there are times when it is interesting to apply the curing means (13) to the strip portion of the adhesive layer (1) that corresponds to the unformed strip portion of the covering sheet (2) (as just mentioned above). This is because sometimes the unformed strip portion is very narrow, and therefore, when the continuous strip portion of the covering sheet (2) is formed, relative displacement may occur between the covering sheet (2) and the panel (3) in the narrow unformed strip portion. For this reason, it is also interesting to apply the curing means (13) to these unformed strip portions in order to increase the strength of the adhesion of the covering sheet (2) to the panel (3) in those strip portions and to prevent any subsequent relative displacement that may occur between the covering sheet (2) and the panel (3).

[0096] As already mentioned when describing Figure 5, the adhesive bonding method of the substrate of the present invention anticipates applying the curing means (13) at different timings throughout the lamination process.

[0097] Figure 12 shows the first application of the curing means (13) to the adhesive layer (1) corresponding to the first central strip portion (2a) of the covering sheet (2), which is then placed in the open area of ​​the panel (3) and not post-molded, as seen in Figure 13. The diagram in Figure 12 corresponds to the cross section HH shown in Figure 5.

[0098] Figure 13 corresponds to section II shown in Figure 5. Figure 13 shows the second application of the curing means (13) to the adhesive layer (1) corresponding to the second strip portion (2b) of the covering sheet (2) which is post-formed onto each contour (14) of the panel (3). The contour (14) to which the covering sheet (2) is post-formed is located at the left end of the panel (3) and has a linear shape. The other contour (14) is located on the right side (14) of the panel (3) and is the first step of a series of stepped steps.

[0099] Figure 14 shows the second strip portion (2b) of the covering sheet (2) shown in Figure 13, which has already been post-formed onto the panel (3). Figure 14 shows the third application of the curing means (13) to the adhesive layer (1) corresponding to the third strip portion (2c) of the covering sheet (2) which will be post-formed onto each contour (14) of the panel (3). This diagram in Figure 14 corresponds to the cross section JJ shown in Figure 5.

[0100] Figure 15 shows the third strip portion (2c) of the covering sheet (2) shown in Figure 14, which has already been post-formed onto the panel (3). Figure 15 shows the fourth application of the curing means (13) to the adhesive layer (1) corresponding to the fourth strip portion (2d) of the covering sheet (2) which will be post-formed onto each contour (14) of the panel (3). This diagram in Figure 15 corresponds to the cross section KK shown in Figure 5.

[0101] Figure 16 shows the covering sheet (2) of Figure 5, fully post-formed onto panel (3) of Figure 5 (in the corresponding strip portions (2b, 2c, 2d)). This diagram in Figure 16 corresponds to the cross section LL shown in Figure 5.

[0102] Figure 17 shows an additional embodiment of a laminated panel manufacturing system with post-forming, similar to the embodiment shown in Figure 5, according to the present invention. Here, unlike in Figure 5, it is considered that additional adhesive (1) is applied to the panel (3) by application rollers (4) and additive rollers (5) before the placement of the covering sheet (2) on the panel (3). Between placement by placement rollers (9) and application of adhesive (1) to the panel (3), smoothing by smoothing rollers (7) and partial curing by curing means (13), such as ultraviolet radiation, are performed.

[0103] Figure 18 shows an additional embodiment of the system for manufacturing laminated panels according to the present invention, in which, unlike the embodiments described above, the adhesive layer is applied only to the panel (3) and not to the sheet (2). In the example of the embodiment shown, no post-molding is performed.

[0104] Figure 19 shows an additional embodiment of the system for manufacturing laminated panels according to the present invention, in which, unlike the embodiment described above, the coating sheets (2) are supplied discontinuously from a stack of coating sheets (2), i.e., sheet by sheet. In the illustrated embodiment, no post-molding is performed.

[0105] Figures 20a, 20b, 20c, and 22 show cross-sectional views of panel (3) in the corresponding cross-sections MM, NN, OO, and SS of the embodiment shown in the previous figure.

[0106] Figures 21a, 21b, and 21c show cross-sectional views of sheet (2) in the corresponding cross-sections PP, QQ, and RR of the embodiment shown in the previous figure. [Explanation of Symbols]

[0107] 1. Adhesive, adhesive layer 2. Covering sheet 2a, 2b, 2c, 2d Band-shaped area 2' End band 3 Panels 4. Application roller 5. Addition roller 6 Lip 7. Smoothing Roller 8. Post-molding roller 9. Placement rollers 10 Guide rollers 11 coils 13 Radiation curing means 14. Strip-shaped portion, cross-section, or contour 15 Adhesive spray nozzle

Claims

1. A method for adhesive bonding of substrates, - Applying the adhesive layer (1) to the first substrate and / or the second substrate, - Placing the first substrate on the second substrate via the applied adhesive layer (1) A method for bonding substrates, comprising: the adhesive layer (1) being capable of being cured or polymerized by radiation; the method comprising post-forming by post-forming means (8; 12) covering at least one end of the second substrate with at least one strip portion (2', 2b, 2c, 2d) of the first substrate in order to position the first substrate on the second substrate; and radiation curing means (13) incompletely curing the adhesive layer (1) on the first substrate and / or the second substrate to a degree of curing suitable for post-forming with respect to the at least one strip portion (2', 2b, 2c, 2d) of the first substrate and / or the at least one end of the second substrate before and / or during the post-forming at at least one end of the second substrate.

2. The method for bonding substrates according to claim 1, comprising, in a plurality of steps, post-forming different strip portions (2', 2b, 2c, 2d) of the first substrate onto different ends of the second substrate using the post-forming means (8; 12), wherein the method comprises, between two of the post-forming steps, at least one additional application of the curing means (13).

3. A method for bonding substrates according to claim 1 or 2, characterized in that the curing means (13) is applied to the adhesive layer (1) on the first substrate and / or the second substrate at a first strip-shaped portion (2a) of the first substrate that is not post-molded and / or at one end of the second substrate that is not post-molded.

4. The adhesive bonding method for a substrate according to any one of claims 1 to 3, characterized in that the application of the curing means (13) includes applying radiation selected from the group consisting of electromagnetic radiation, particularly ultraviolet or infrared radiation, and particle beams, particularly particle beams using electrons, to the adhesive layer (1).

5. A method for bonding substrates according to any one of claims 1 to 4, characterized in that the adhesive layer (1) is smoothed immediately after being applied to the first substrate and / or the second substrate.

6. The adhesive bonding method for substrates according to any one of claims 1 to 5, characterized in that the first substrate is a coating material (2), and the second substrate is a coating support (3) on which the coating material (2) is disposed.

7. A method for bonding substrates according to any one of claims 1 to 6, characterized by using an adhesive having an additional curing mechanism in addition to a radiation curing mechanism, particularly an adhesive having a double curing mechanism.

8. The method for bonding substrates according to claim 7, characterized in that the additional curing mechanism is due to a reaction with moisture in the air, and the adhesive is particularly composed of reactive PUR.

9. A substrate adhesive bonding system, wherein the first substrate is a coating material (2), and the second substrate is a coating support (3) on which the coating material (2) is placed, and the system is A coating means for applying an adhesive layer (1) to the coating material (2) and / or the coating support (3), Arrangement means (8; 9, 12) for arranging the covering material (2) on the covering support (3) The system includes, and the adhesive layer (1) is capable of being cured or polymerized by radiation, and the system is A substrate adhesive bonding system comprising a radiation curing means (13) disposed between the coating means for applying the adhesive layer (1) and the placement means (8; 9, 12), wherein the placement means (8; 9, 12) includes a post-forming means (8; 9, 12) for post-forming which covers at least one end of the covering support (3) with at least one strip-shaped portion (2', 2b, 2c, 2d) of the covering material (2), and wherein the radiation curing means (13) partially cures the adhesive layer (1) on the first substrate and / or the second substrate to a degree of curing suitable for post-forming with respect to the at least one strip-shaped portion (2', 2b, 2c, 2d) of the first substrate and / or the at least one end of the second substrate, before and / or during the post-forming on the at least one end of the second substrate.

10. The adhesive bonding system for a substrate according to claim 9, characterized in that it is configured to carry out the method described in any one of claims 1 to 8.

11. A product of adhesive bonding of a substrate, characterized by being obtained by the method described in any one of claims 1 to 8.

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