MXPA99002876A - Production of striped coatings on strip - Google Patents

Abstract

An apparatus and method for producing a striped coating on a continuous moving strip. The apparatus has a smoothing device including a doctor roll (4) forming a nip with the strip (5). A stationary partition means (8) is provided dividing the nip into nip lengths. Upstream of the smoothing device (4, 5) is a means to deposit coating materials on the strip (5) for delivery into the respective nip lengths at predetermined rates. The deposit means maintain a bead (9) of coating material in each nip length and a stripe of coating material is formed on the strip from coating material escaping the respective nip length as the strip (5) passes through the nip.

Description

PRODUCTION OF STRIPED COATINGS ON A TAPE TECHNICAL FIELD This invention relates to a method and apparatus for the continuous application of liquid or semi-liquid coatings to a movable substrate tape. The invention has been developed primarily for the application of paint coating to substrates of metal tapes, for example steel tapes, and is described mainly in that context subsequently. However, it will be apparent that the invention is applicable to the application of other liquid or semi-liquid coatings for substrates or coating other materials, provided that the substrate or tape is substantially impervious to the coating.

BACKGROUND OF THE INVENTION The large-scale application of paint to substrates such as steel tape in continuous operation, rolled steel is a highly developed technique, but has been restricted so far to the production of a monochromic product, which is characterized by applying a uniform coating to all or at least one side of the tape. Said application is described in EP-494672.

The present invention exceeds the limit of the prior art and provides for the continuous and simultaneous application of different coatings to each of the two contiguous longitudinally extending zones of the belt.

DESCRIPTION OF THE INVENTION Applicants have found that if two adjacent, but non-contiguous adjacent flanges of liquid or semi-liquid coating material are held in an upwardly running grip defined by a movable tape and a treatment roll extending transversely of the tape, it can subsequently be achieved. a condition of fixed state, whereby the tape exiting downstream of the roll is coated with respectively derived coatings from each flange and the coatings are brought into contact with each other, but without substantially intermixing. In addition, the joining line between the projecting coatings can be direct and placed in a fixed manner on the belt. In this way, if the two ridges of similar paint compositions, but of different colors, will be maintained in this way, the result is a clearly scratched product. In accordance with one aspect of the invention, there is provided a method of coating a tape including the steps of moving the tape to be coated through a smoothing device, including a treatment roll to form an upstream grip between the tape. tape and the treatment roll, which places at least one stationary dividing means to divide said grip into at least two adjacent grip lengths, and deposit the coating materials upstream of said smoothing device to feed the lengths of respective grip at speeds that maintain a rim of coating material at each grip length; A strip of lining material is formed from each grip length in each belt, as the belt passes through the grip. It is preferable that the coating materials are liquid or semi-liquid when they are deposited on the tape and the coating materials fed to each grip length preferably have different physical characteristics. The reference to the coating materials having different characteristics include coating materials having different colors. In preferred embodiments, boundary means similar to said dividing means may be provided at each edge of the tape. These limit means can be immediately adjacent to the belt, that is, they can come into contact with their respective edges of the belt passing between them, or they can rest and make contact with the narrow margins of the edge of the belt. In this last case, the limit means may have a width approximately equal to half of, or each, of the dividing means.

In preferred embodiments, the deposition rates of the coating materials are selected and controlled to ensure that the individual flanges of the coating material at the respective grip lengths have substantially constant volumes under an operation in the fixed state. This requires the deposition rate for each grip length at the substantially equal velocity at which the material escapes from each grip length. When the roll pressure is established to produce the coating of the desired thickness and there is a sufficient extension of the material, it escapes from each grip length by the processing roll to produce a continuous, uninterrupted and downwardly flowing coating. When the respective coating compositions are substantially of the same viscosity, the individual flanges are not only substantially constant in volume of fixed state, but are also substantially equal in volume of fixed state per unit grip length. This also facilitates the formation of a coating of the desired thickness without interruption or interference in the joining or joining of the tapes. The equality is expressed in a base grip length per unit volume, since the invention is applied to instances in which the individual tapes differ in width, and hence the different lengths of grip sizes are produced to produce effects different aesthetics in the finished product.

The width of the dividing means depends on the viscosity and extension characteristics of the coating material in the belt. When the individual coating compositions have different viscosities or different extension characteristics, it may be desired to use different dividing means or widths (as measured in the axial direction on the treatment roller) between different pairs of close grip lengths. In another aspect of the invention, there is provided an apparatus for producing a striped coating on a continuous movable belt, which includes: a smoothing device including a treatment roll that forms a grip with the belt, at least one means of stationary division on the belt; grip, which divides said grip into at least two adjacent grip lengths and upstream means of said smoothing device to deposit the coating materials on the belt to feed at the respective grip lengths at predetermined speeds, said deposit means , which hold a flange of facing material at each grip length, a strip of facing material that is formed from each grip length on said belt, as the belt passes through said grip. In preferred embodiments, when the tape can resist being heated to higher temperatures, either at glass transition temperatures or at melting points of the coating materials, as the case may be, the means for depositing the liquid or semi-liquid coating materials. they can be melt depositories of the kind that drive a block of substantially solid coating material towards the heated strip at a predetermined rate to cause the liquid or semi-liquid material to merge into the block and deposit on the belt. Said fusion depositors are described in our Australian Patent No. 667716 and our co-pending International Patent Application No. PCT / AU97 / 00555, filed on August 28, 1997, entitled "Apparatus and Method for Block Feeding", the content of which is incorporated herein by reference. Such fusion depositors are preferred, since they provide precise control over the rate of deposition. They also allow easy deposition in selected areas of the belt, to facilitate the feeding of the individual tanks to the respective grip lengths.

PREFERRED MODALITY By way of example, one embodiment of the invention described above is described in more detail below with reference to the accompanying drawings. Figure 1 is a diagrammatic, not to scale, side elevation of a continuous ribbon melt deposition painting apparatus, including a smoothing device in accordance with the invention.

Figure 2 is a detail greatly enlarged from a part of Figure 1 within the closure marked with the number 2 in the figure; Figure 3 is a perspective view of an enlarged diagram of a ribbon passing through the device; of smoothing shown in Figure 1. Figure 4 is an end view of the subject matter of Figure 3 illustrated on a larger scale. Figures 5 to 8 illustrate the multiple effective arrangements for a fusion depositor. The illustrated paint apparatus shown in Figure 1 includes a rotating roller 3 and a supporting roll 4, whereby the ribbon 5 to be painted is guided through a melting deposition station. The apparatus also includes a belt preheating furnace 6, whereby the belt 5 is brought to a temperature above the glass transition temperature of the solid paint composition that will melt deposited on the belt. In addition, the apparatus includes a device for extending and smoothing the paint, including an elastomeric roller 7, and a healing furnace 8 for use in the instances when the composition of the paint is thermoset in nature. The apparatus described in the previous paragraph is in accordance with the invention proposed in the aforementioned Australian patent No. 667716, and the international patent application No. PCT / AU97 / 00555, filed on August 28, 1997 and entitled "Apparatus and Method for Block Feeding ", the contents of which are incorporated herein by reference and the apparatus described above can be used with any known block feed means for liquid paint composition of melting tank in the belt at the deposition station. In the apparatus shown in Figure 1, the apparatus for block feeding or depositing the coating material on the heated belt includes a conveyor belt means shown as an endless conveyor belt 9 which includes a conveyor belt 10, which includes a path substantially flat 11, which passes around a head pulley 12 and flips the means including a stationary guide 13 and a loose pulley 14. The head pulley 12 is driven by a motor and a pulse transmission (not shown), by what the speed of rotation of the head pulley can be set exactly to any desired value within the scale of values. The path of the conveyor belt 11 is adapted to support a column of at least two blocks 15 of the paint composition substantially free of solvent. To that end, the path 11 can slide on a support table in the event that the stationary guide of the overturning means is no more than the edge of the end of the table. In the embodiment shown, the guide 13 is a beam of a standard, hollow and rectangular section that traverses the total width of the conveyor belt. In this way, it has a small radius, a longitudinal corner 16 around which the conveyor belt 10 rotates and moves away from the plane of the path 11 at the end 17 of the path 11. After turning, the conveyor belt continues in a direction, which is parallel or diverges from the phase of the tape that will be painted or coated. The head pulley 12 is preferably smoothed with a high friction material such as a natural rubber. Preferably, it is mounted on a slidable support or the like which is continuously driven away from the tumbling means by an adjustable loading spring or the like. These arrangements provide a slip free drive transmission between the head pulley 12 and the conveyor belt 10, so that the path 11 advances towards the belt 5 at a predetermined speed established by the rotational speed of the pulley. In other embodiments, the surface of the conveyor belt that contacts the head pulley can channel or mesh transversely and the surface of the pulley can be correspondingly stopped to provide a positive impulse connection therebetween. The conveyor belt 10 is made of a flexible, heat resistant and durable material. For example, it may be a fluorinated polymer reinforced with a woolen fabric or, for example, glass fiber. The surface of the conveyor belt in contact with the blocks 15 is preferably smooth. The thermoset paint compositions in block form tend to adhere to the surface and the material of the conveyor belt, mentioned in the previous paragraph, is certainly said surface. This results in a high friction contact between the conveyor belt 10 and the blocks 15, whereby the control of the speed of the conveyor belt is translated into the control of the speed of the block, as needed for the control of the fusion deposition rate. The smoothing device, illustrated in accordance with the invention and shown in Figures 1 and 3, can be included as a component of a continuous line of paint in a particular steel mill. The invention includes a conventional steel support roll 4 and a conventional smoothing treatment roll 7 with a cylindrical surface layer of elastomeric outlet. A steel belt 5 is supported by and passes over the support roll 4. Both rolls are driven by energy and their surface speeds are not necessarily the same. The support roller 4 is driven so that its surface velocity is substantially the same as that of the belt 5 and that part of the roller touching the belt moves in the same direction as the belt. Otherwise, the surface speed of the smoothing treatment roll may have a scale between a low speed in the direction opposite to the belt movement, through 0 and up to 25% of the speed of the belt in the same direction than the speed of the tape. A pressure is maintained between the rollers and the belt is sufficient to cause the necessary extension of the coating material, which escapes from each grip length. In the embodiment of the invention, it is preferable to use the melter depositor upstream of the smoothing device, which includes a chain block feeder, whereby two or more bearing blocks, preferably as illustrated in FIG. place one on top of another, separated by a distance greater than the thickness of the paint blocks or a side-by-side arrangement across the width of the movable tape. The chain block feeder deposits color compositions differently, free of solvent and liquid paint, indicated by the cross shades 19 and 20 on one side of the belt. Tanks 19 and 20 are relatively rough and irregular, but are deposited at very precise deposition rates. It will be seen that the deposits do not completely cover the side of the belt, but are arranged in two spaced longitudinal zones, which are also spaced apart from the edges of the belt. In this way, the melting deposition means includes two separate units, one for each paint block or are adapted to drive two blocks spaced simultaneously at the same speed of each. A single dividing medium including a stationary sheet 21 of, for example, Teflon or other heat-resistant and non-tacky material, divides the upwardly running grip defined by the tape 5 and the smoothing treatment roll 7 in two lengths of grip separated by the width of the sheet 21. The sheet 21 is held in a stationary manner by a suitable fastening means (not shown) passing through the tape 5. It has a cusp shape at one end that fits exactly to the grip, as much as possible without obstructing the roller 7.

In this regard, you must realize that the roller 7 is compressed by the pressure between it and the thin liquid layer in the belt 5, which passes through the grip on the downstream side. In this way, the tip of the apex of the sheet 21 is spaced an upward current at a small distance from the imaginary plane, in which the axes of both rollers meet. The limit means 18 may be provided at each edge of the tape. The limit means may be immediately adjacent to the belt, that is, they may contact the respective edges of the belt 5 passing through them or they may pass over and contact the narrow margins of the edge of the belt. . In the latter case, the boundary means may have a width approximately equal to half of or each division means. In the beginning, two flanges 22 and 23 of the respective coating materials are formed from each grip length. The material of each grip length enters the contact zone between the roller 7 and the belt 5. Subsequently, the roller extends the material, whereby the material of each ridge covers a section of the belt. This extension slightly reduces the average thickness of the material layer and allows the roller 7 to produce a desirably smooth coating, which includes two strips 24 and 25 respectively. Examples of special arrangements of chain block feeders of melt depositories are illustrated in Figures 5-8.

The two or more trajectories can operate in unison (for example, sliding together in a common support table) and operate at the same time. When the conveyor belt means are endless conveyor belts, the head pulleys of each trajectory can operate independently of the other, so that the speed of rotation of the conveyor belts can do the same or can vary. Also, it would be desirable for the trajectories to slide on the support table independently. Figure 5 shows the arrangement of the conveyor belt of the chain-melt depositor when two blocks 42 of the coating material are used to coat the slip and Figure 7 shows an arrangement of the conveyor belt for the three blocks 44. The number of Conveyor belts is preferably equal to the number of blocks of coating material used. In Figures 6 and 8, if the paths in which the blocks travel can slide independently of one another, then the blocks 44, 42 in the upper path shown in Figures 6 and 8 can move and paint a combination of colors, while the blocks 45, 43 of the background path can be loaded with a second combination of ready-to-paint colors when the first color combination is not required for a longer time. From here, the upper path can be retracted even when the background path moves in the painting position to start painting and increase the speed with which the color will be applied to the tape that can be changed.

Claims (26)

NOVELTY OF THE INVENTION CLAIMS

1. - An apparatus for producing a striped coating on a continuously moving belt, including a smoothing device including a treatment roll that forms a grip with the belt, at least one means of stationary division on the belt, which divides said belt gripping at least two adjacent grip lengths and upstream means of said smoothing device for depositing coating materials on the belt to feed at the respective grip lengths at predetermined speeds, said deposit means holding a ridge of material of coating on each grip length, a strip of coating material that is formed from each grip length on said belt as the belt passes through said grip.

2. The apparatus according to claim 1, further characterized in that the smoothing device further includes a support roller, the steel belt passes over and is supported by the support roller.

3. The apparatus according to claim 2, further characterized in that the pressure is maintained between the support roller and the treatment roller to extend the coating material escaping from each grip length.

4. - The apparatus according to claims 1, 2 or 3, further characterized in that the coating materials are liquid or semi-liquid when they are deposited on the belt.

5. The apparatus according to claim 2, further characterized in that the means for depositing coating materials is a melt depositor.

6. The apparatus according to claim 5, further characterized in that the melt depositor moves at least two blocks of substantially solid coating material towards the heated strip at a predetermined speed to cause the liquid semiliquid material to be melted from the blocks. and deposited on the tape.

7. The apparatus of any of the preceding claims, further characterized in that the limit means are provided at each edge of the belt.

8. The apparatus according to claim 7, further characterized in that the limit means pass over and come in contact with the margins of the edge of the belt.

9. The apparatus according to claim 7, further characterized in that at least two stationary dividing means are provided.

10. The apparatus according to claim 6, further characterized in that the melt depositor includes at least two rows of a conveyor belt extending across the width of the belt, the number of conveyor belts corresponding to the number of blocks of substantially solid coating material, each row of conveyor belts is operated independently of any other belt.

11. A method for coating a tape that includes the steps of moving the tape to be coated through a smoothing device, which includes a treatment roll to form an upward grip between the tape and the treatment roll, placing at least one stationary dividing means for dividing said grip into at least two adjacent grip lengths and depositing the facing materials upstream of the belt of said smoothing device to feed them to their respective grip lengths at speeds that maintain a flange of facing material at each grip length; a strip of coating material that is formed from each grip length in said tape, as the tape passes through the grip.

12. The method according to claim 11, further characterized in that the coating materials are liquid or semi-liquid when they are deposited on the belt.

13. The method according to claim 12, further characterized in that the coating materials fed to each grip have different physical characteristics.

14. - The method according to claim 13, further characterized in that the different features include the coating materials having different colors.

15. The method according to any of claims 11-14, further characterized in that the adjacent grip lengths are not contiguous.

16. The method according to claim 15, further characterized in that the deposition rates of the coating materials are controlled to provide individual ridges of coating material of substantially constant volume at the respective grip lengths under operation in the fixed state.

17. The method according to claim 16, further characterized in that the rate of deposition of each grip length is substantially equal to the speed at which the coating material is extended at each grip length.

18. The method according to claim 17, further characterized in that the viscosities of the respective coating materials are substantially the same.

19. The method according to claim 18, further characterized in that during the operation the respective volumes per unit grip length of the individual flanges are substantially equal.

20. - The method according to claim 17, further characterized in that the grip is divided into grip lengths of different size.

21. The method according to any of claims 15-19, further characterized in that the smoothing device further includes a support wall.

22. The method according to claim 21, including the step of maintaining a sufficient pressure between the support roller and the treatment roller to extend the coating material escaping from each grip length.

23. The method according to claim 11, further characterized in that the coating material is deposited on the belt with a melt depositor.

24. The method according to claim 23, further characterized in that the melt depositor moves at least two blocks of substantially solid coating material towards the heated strip at a predetermined speed to cause the liquid semiliquid material to melt from the blocks and deposit on the tape.

25. The method according to claim 24, further characterized in that the melt depositor includes at least two chain conveyor belts extending across the width of the belt, the number of conveyor belts corresponding to the number of blocks, Conveyor belts move the blocks towards the heated belt.

26. The method according to claim 25, further characterized in that each conveyor belt is operated independently of other conveyor belts.