System for coating continuous sheets

Abstract

A system for coating a continuous sheet (1), comprising: an application roller (10) for applying a coating to a surface of the sheet (1) when the sheet (1) is pressed against the application roller (10) by an application pressure element (11); and a smoothing roller (20) for smoothing the coating applied to the surface of the sheet (1) by contacting the smoothing roller (20) with the coating when the sheet (1) is pressed against the smoothing roller (20) by a smoothing pressure element (21), wherein the application (11) and the smoothing pressure element (21) are independently movable to press the sheet (1).

Description

[Technical Field]

[0001] The present invention relates to the roller application of a coating product to a sheet or thin layer of material in a continuous process. The present invention particularly relates to the preparation of a continuous sheet for coating furniture components such as panels or profiles by using an adhesive or pressure-sensitive adhesive as the coating product. [Background technology]

[0002] Currently, roller application systems are widely known for applying a coating or layer of a coating product, such as an adhesive or pressure sensitive adhesive, to a continuous sheet, in which an application roller applies the coating to the surface of the sheet when the sheet is pressed against the application roller by an application pressure element in a coating product transport area.

[0003] These roller application systems make it possible to achieve a uniform distribution of the coating on the surface of the sheet, which is useful in adhesive applications where the coating product applied to the sheet is an adhesive or pressure sensitive adhesive, as it can eliminate defects that may appear when fastening the sheet to a base part as a result of differences in the mass of the applied adhesive.

[0004] Furthermore, in so-called high gloss coatings where high gloss sheets are used, in other words made from materials with a surface gloss similar to that of a mirror, and in transparent coatings where transparent sheets are used, any small defects become more visible, for which reason uniform application of adhesive is particularly problematic. Patent document 1 describes a roller application system for applying adhesive to continuous sheets for high gloss applications. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Spanish Patent Application Publication No. 2394833 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the existing known methods, the present invention aims to provide a system for coating continuous sheets that makes it possible to obtain uniform coatings in an improved manner, with particular utility for high gloss, clear or similar coatings, whose characteristics make application defects easily visible. [Means for solving the problem]

[0007] In order to meet this objective and solve the technical problems set out so far, as well as to provide additional advantages that can be derived later, the present invention relates to a system for coating a continuous sheet, comprising an application roller for applying a coating to a surface of the sheet when the sheet is pressed against the application roller by an application pressure element.

[0008] The coating system according to the present invention further includes a smoothing roller for smoothing the coating applied to the surface of the sheet by contacting the smoothing roller with the coating when the sheet is pressed against the smoothing roller by the smoothing pressing element.

[0009] This sequential arrangement of the application roller and the smoothing roller allows the smoothing roller to impart the required greater uniformity to the applied coating as soon as the coating is applied to the continuous sheet surface by the application roller.

[0010] According to the present invention, the application pressure element and the smoothing pressure element are independently movable to press the sheet. In other words, they can independently approach the respective application roller or smoothing roller. This independent movement capability allows the applied coating to be uniform or smoothed by independently adjusting the uniformity or smoothness of the applied coating, thereby providing an optimized uniform or smooth coating.

[0011] Preferably, the application pressure element and / or the smoothing pressure element can be adjustable in its movement, which in the context of the present invention is understood to mean that the pressure element can be moved from an initial position to a number of selected different final positions, in particular final positions in which the pressure element applies different pressures to the application roller or smoothing roller, respectively.

[0012] Adjusting the movement of the pressure element makes it possible to adjust the required coating uniformity. In this respect, the pressure element is designed so that it can be moved continuously and its movement can be adjusted in a more precise manner, thereby making it possible to more precisely adjust the uniformity of the coating applied to the sheet.

[0013] Preferably, the system of the present invention may also include a movement control device for controlling the movement of the application pressure element and / or the smoothing pressure element. In the context of the present invention, the control of the movement, in particular the control of the adjustment of the movement, is understood to mean the movement being executed according to a program or instructions stored in the control device. This can simplify or speed up the operation of the system to obtain an optimally uniform coating.

[0014] Likewise, control can be performed automatically, for example by processing by a control device operating parameters of the system such as the weight per unit area of ​​the coating product, the characteristics of the sheet or of the components covered by the sheet (e.g., porosity of the sheet or of the panel being bonded, thickness of the sheet being bonded, etc.), the advancement speed or tension of the sheet, the advancement speed of the components, etc. This control can be performed without stopping the system to adjust the movement of the pressure element, and can even be performed in real time. For example, it is advantageous to select a lower pressure of the smoothing pressure element for a larger weight per unit area of ​​applied coating to obtain an optimal uniform coating for a smaller weight per unit area of ​​applied coating.

[0015] The present invention therefore provides a system for coating continuous sheets that makes it possible to obtain improved uniform smoothing, particularly for high gloss, clear or similar coating applications where this characteristic makes application defects easily visible. [Brief explanation of the drawings]

[0016] The following figures are included as part of the description of at least one embodiment of the present invention. [Figure 1] 1 shows one embodiment of a system for coating a continuous sheet (1) according to the present invention, where the coating product is an adhesive (2) that is applied to the sheet (1) in order to cover a panel (3) with the sheet (1). [Figure 2] 1 shows another embodiment of a system for coating a continuous sheet (1) according to the present invention, where the coating product is an adhesive (2) that is applied to the sheet (1) to bond the sheet (1) to another continuous sheet. [Figure 3] For the embodiment of Figures 1 and 2, the application roller (10), smoothing roller (20) and application (11) and smoothing pressing element (21), respectively, as well as other components of the system, are shown in detail. [Figure 4]4a, 4b and 4c show successive steps of an example of the operation of the system for the embodiment of FIGS. 1 to 3. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention relates to a system for applying coatings, such as aesthetic coatings, to furniture components, such as panels or profiles, which system of the invention achieves characteristics that meet the requirements necessary for high gloss, clear or similar coating applications.

[0018] In the applications described below, adhesive (2) is used as a coating product, and a hot melt adhesive such as PUR, particularly a transparent adhesive (2), can be used. Transparent adhesives are effectively used to adhere transparent sheets, which allow proper visibility of the bottom surface of the coating.

[0019] The system of the present invention includes an application head (40) having an application roller (10) and an application roller (50). The application roller (50) cooperates with the application roller (10) to apply a quantity of adhesive (2) to the surface of the application roller (10) by rotation and relative movement of the application roller (10) and the application roller (50). An application pressure element (11) presses the sheet (1) against the application roller (10) so that the adhesive (2) is applied to the surface of the sheet (1).

[0020] Once the adhesive (2) has been applied to the sheet (1), the coating thus obtained is smoothed by a smoothing roller (20) arranged after the application roller (10) in the forward direction of the sheet (1). A smoothing pressure element (21) presses the sheet (1) against the smoothing roller (20) in order to smooth the adhesive coating applied by the application roller (10).

[0021] The continuous sheet (1) is fed from a supply reel (4) using a guide roller (9) and passes between an application roller (10) and an application pressing element (11) and between a smoothing roller (20) and a smoothing pressing element (21).

[0022] The shown embodiment of the application head (40) is not limiting, since the dosing roller (50) and the application roller (10) can also rotate in the same direction, and likewise the application of adhesive (2) to the application roller (10) can be by other means, for example by a pass-restricting element in the form of a blade or scraper, or by an edge melter. As shown in Figure 3, the invention is also designed so that a smoothing roller (20) can be attached to the application head (40) together with the application roller (10) and, if applicable, the dosing roller (50).

[0023] Similarly, the relationship between the application roller (10) and the sheet (1) can be such that the application roller (10) rotates in the direction of advancement of the sheet (1) as shown, or can rotate in the opposite direction without changing the practical function of the system.

[0024] Similarly, the smoothing roller (20) can rotate in the opposite direction to the sheet advance direction, as shown, or in the same direction. The rotation of the smoothing roller (20) makes it possible to prevent localized wear of the roller and also facilitates the removal of excess coating product from the smoothing, which can be collected by an element that restricts the passage of the coating product, such as a blade (22).

[0025] In the embodiment of the system shown in Figure 1, after smoothing, the sheet (1) passes through two successive calendering assemblies, each containing a calender roll (7), (8). Calendering secures the bonded sheet (1) to the panel (3), covering it and favoring a perfectly uniform bond. The first calender roll (7) allows the sheet to be attached to the base part, while the second calender roll (8) allows the bond to be further uniform.

[0026] In the embodiment of the system shown in Figure 2, after smoothing, the sheet (1) passes through two successive calendering assemblies, each containing a respective calender roll (7) and (8). Unlike the embodiment shown in Figure 1, the adhesive-applied sheet (1) is secured by calendering to another continuous sheet supplied from a separate supply reel (5), which also favors a perfectly uniform bond. In the same way, the adhesive-applied sheet can be applied to another sheet by the first calender roll (7), and the second calender roll (8) can further uniformize the bond. The laminate obtained by bonding both sheets is wound up on the collection reel (6).

[0027] In the illustrated embodiment, the application (11) and the smoothing and pressing element (21) take the form of a rotating roller, but are not limited to this embodiment. Different application (11) or smoothing and pressing elements (21) can alternatively be used, for example, lubricants, pneumatic cushions, etc. Rotating rollers are advantageous as they make it possible to reduce friction and localized wear of the sheet by the pressing elements.

[0028] According to the invention, the pressure elements 11, 21 can be interchangeable and can be made of different materials and have sizes to suit different applications, in particular it is possible to have pressure elements 11, 21 with different lengths to accommodate different widths of sheets.

[0029] In a preferred embodiment according to the present invention, the application (10), addition (50) and smoothing rollers (20) are metal, providing greater durability and less maintenance compared to rubber-coated rollers. More preferably, the metal rollers are heated to facilitate application and smoothing of the coating product, especially in the case of hot melt adhesives.

[0030] To move the application or smoothing pressure element, an actuator, for example a linear actuator, can be used. Figure 3 shows an application movement actuator (31) for moving the application pressure element (11) and a smoothing movement actuator (32) for moving the smoothing pressure element (21).

[0031] For example, by means of a pneumatic actuator, the corresponding pressing element (11), (21) can be moved from an initial position where it exerts no pressure on the sheet (1) against the application (10) or smoothing roller (20) to a final position where it exerts pressure on the sheet (1) against that roller (10), (20). For example, by means of a worm screw actuator, the pressing element (11), (21) can be moved in a regulated and continuous manner to different positions where it exerts different pressures on the roller (10), (20).

[0032] FIG. 3 shows a movement control device (30) acting on the application (31) and smoothing movement actuators (32) to control the movement or adjustment of the application (11) and smoothing pressure elements (21).

[0033] In the illustrated embodiment, the movement control device (30) is configured so that the smoothing pressure element (21) begins to press the sheet (1) against the smoothing roller (20) after the application pressure element (11) presses the sheet (1) against the application roller (10). Figures 4a, 4b, and 4c show a series of movements of the pressure elements (11) and (21) controlled in this manner, which allows for a smooth transition during system startup.

[0034] In particular, according to the exemplary embodiment of the previous paragraph, the motion control device 30 can be configured so that the smoothing pressing element 21 begins to press the sheet 1 against the smoothing roller 20 when the sheet 1 reaches a certain tension and / or forward speed, thereby preventing wrinkles and tension that could bend the sheet 1.

[0035] In another exemplary embodiment, the movement control device (30) is configured to move the smoothing pressure element (21) while keeping the application pressure element (11) fixed, thereby allowing only the movement of the smoothing pressure element to be varied to vary the pressure applied to the sheet (1) against the smoothing roller (20), facilitating proper control of the uniformity of the applied coating. [Explanation of symbols]

[0036] 1 continuous sheet 2. Adhesive 3 Panels 4 Supply Reels 5 Supply Reel 6 Recovery Reel 7. First calendar roll 8. Second calendar roll 9 Guide Roller 10 Application roller 11. Application pressing element 20 Smoothing roller 21 Smoothing Pressing Element 22 blades 30 Movement control device 31 Application movement actuator 32 Smoothing Movement Actuator 40 application head 50 Additive Roller

Claims

1. 1. A system for coating a continuous sheet, comprising: an application roller for applying a coating to a surface of the sheet when the sheet is pressed against the application roller by an application pressure element; a smoothing roller for smoothing the coating applied to the surface of the sheet by contacting the smoothing roller with the coating when the sheet is pressed against the smoothing roller by a smoothing pressing element; wherein the application pressure element and the smoothing pressure element are independently movable to press the sheet, and the system includes a movement control device for controlling movement of the application pressure element and / or the smoothing pressure element, and the movement control device is configured such that after the application pressure element presses the sheet against the application roller, the smoothing pressure element begins to press the sheet against the smoothing roller.

2. 2. The system for coating a continuous sheet according to claim 1, wherein the movement of the application pressure element and / or the smoothing pressure element is adjustable.

3. 3. The system for coating a continuous sheet according to claim 2, characterized in that the movement control device is configured so that the smoothing pressure element begins to press the sheet against the smoothing roller when the sheet reaches a certain tension and / or advancement speed.

4. 4. The system for coating a continuous sheet according to claim 1, wherein the movement control device is configured to move the smoothing pressure element while keeping the application pressure element fixed.

5. 5. A system for coating a continuous sheet according to claim 1, characterized in that the system comprises an application head to which the application roller and the smoothing roller are attached.

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