DE102020128123A1 - Process for producing a flat substrate - Google Patents

Abstract

In a method for producing a flat substrate (4), in particular a film made of one or more layers, by means of at least one roller (1, 2), via which a thickness of the flat substrate (4) is determined over its width
- the roller (1) is subjected to heat and/or cold from the outside by a temperature control device (9) arranged across the width of the roller (1),
- a crowning of the roller (1) is determined by means of sensors (11) distributed over the width of the roller (1), and
- when changing the thickness of the substrate (4), the temperature control device (9) for the purpose of changing the crowning of the roller (1) applies heat and/or cold to the roller (1) from the outside in a controlled manner until the crowning has reached the desired thickness of the Substrate (4) generated.

Description

The invention relates to a method for producing a flat substrate, in particular a film made of one or more layers, by means of at least one roller, via which a thickness of the flat substrate is determined, and a device for this.

State of the art

In many cases, flat substrates are produced in so-called calenders. A calender is a system of several heated and polished rolls arranged one on top of the other, through the nips of which a melt or other material is fed. They are mainly used for the production of foils made of plastic, rubber, metal and paper. Of course, not only does a change in shape take place, but also a compression or structural shift. In this respect, the quality of the calendering of a flat substrate essentially depends on the design of the roller gap and its nip forces, and this in turn also on a bending line or crowning of the rollers, which also change increasingly during production as a result of the temperature change of the substrate, roller and environment can. What is desired, however, is to largely maintain the same thickness of the substrate over the length and width of the web.

In the DE 691 15 339 T2 is described, for example, for a size press for the manufacture of paper, that at least one of the rolls forms a variable-crown roll or a roll that is adjustable in zones by means of heat from the inside of the roll, so that by regulating the deflection of the roll with variable crown or by regulating the temperature of the thermally adjustable roll in zones, the linear contact area between a coating bar and the roll is straightened. Something similar, also for paper production, describes the DE 689 06 175 T2 .

For more general use, the DE 10 2004 035 630 A1 a calender roll with a roll shell which has a plurality of heating channels distributed in the circumferential direction and a heating medium connection arrangement for supplying and removing a heating medium, each heating medium channel being part of a flow path which is connected to the heating medium connection arrangement.

the U.S. 3,182,587 already generally describes a calender for the production of a deformable material. This is what the font means in particular rubber, paper or metal. The requirement is that a uniform thickness is maintained across the width of the material in very narrow areas, especially when the end product moves in a very thin area. A very thin area is considered to be a few 1,000ths or 10,000ths of an inch. An arrangement of heating devices is described, which are arranged in the roll or axially separated from one another.

the DE 27 13 917 A1 shows a device for producing a plastic film. The thickness of the film is determined at one point or at several points distributed on a line transverse to the direction of movement and/or the deflection or load on one or more rollers and the setting position of an adjustable roller or several adjustable rollers relative to the common plane the roll axes are changed depending on the result of this determination in such a way that the axis or the axes of this roll or these rolls remains parallel to the adjacent roll axes.

task

The object of the present invention is to specify a method and a device with which a planar substrate can be manufactured very precisely and consistently over both a specified length and a specified width.

solution of the task

• - die Walze von einer über die Breite der Walze angeordneten Temperiereinrichtung von außen her mit Wärme und/oder Kälte beaufschlagt wird;
• - eine Bombierung der Walze mittels über die Breite der Walze verteilt angeordnete Sensoren ermittelt wird;
• - bei Änderung einer Dicke des Substrats die Temperiereinrichtung zum Zwecke der Änderung der Bombierung der Walze die Walze von außen her kontrolliert mit Wärme und/oder Kälte beaufschlagt, bis die Bombierung die gewünschte Dicke des Substrats erzeugt.

The solution to the task is that

• - the roller is subjected to heat and/or cold from the outside by a temperature control device arranged across the width of the roller;
• - a crowning of the roll is determined by means of sensors distributed over the width of the roll;
• - When changing a thickness of the substrate, the temperature control device for the purpose of changing the crowning of the roller, the roller is subjected to heat and/or cold from the outside in a controlled manner until the crowning produces the desired thickness of the substrate.

The substrate, which is produced by the method according to the invention, should be arbitrary within the scope of the invention. At the moment, foils for electrodes of batteries are produced in this way. This makes it clear that it can be a matter not only of a single-layer substrate, but above all of a multi-layer substrate.

The present invention should also not be restricted as far as the temperature control device is concerned. In principle, heating elements are required, which apply heat to the roller, so that the roller expands in certain areas. Since the roller is usually made of metal or metal alloys, it is known that they expand when heated. Conversely, it is of course possible for a roller to become relatively warm during operation and thus experience excessive expansion, which can be reset by cooling in certain areas. Infrared radiant heaters are primarily thought of as warming temperature control elements, cooling elements could be nozzles through which cold air is applied to the roller surface. However, these are only examples; the invention is not limited to them.

Sensors used at the moment are in particular capacitive sensors, which serve as distance sensors and are based on a change in the capacitance of a capacitor. Above all, however, optoelectronic sensors or inductive distance sensors are also conceivable. In the context of the present invention, however, these are only examples.

To determine the width and thickness of the flat substrate, two rollers are usually used, which together form a roller nip. However, the use of only one roller should also be within the scope of the invention. In this case, the substrate sheet is stretched with tension over part of a roller circumference, so that the length of the substrate sheet increases but the thickness decreases. However, this should only be applicable for special substrates, which is why the present description of the method relates primarily to the interaction of two or more rolls that form a calender.

For such a calender it is known to the person skilled in the art that certain nip forces act in the nip for the production of foils, for example. These can be determined via hydraulics, with which the bearings on both sides of the rollers are equipped. There is usually an upper and a lower roller, with one of the rollers being fixed and the other roller supported against the fixed roller by the hydraulics just mentioned. These supporting forces then determine the nip forces in the roller nip, with which one roller presses onto the flat substrate passing through the roller nip. These forces essentially determine the thickness of the flat substrate, while the crowning of the rollers determines a change in the thickness of the flat substrate across the width.

The nip forces and the deflection line (crowning) of the roll for a specific thickness of a specific substrate with cold rolls are well known to those skilled in the art. With most flat substrates, however, heat is transferred to the rolls during calendering, which leads to an expansion of the roll and thus to a change in the camber of the roll. As a result, the thickness of the flat substrate is changed, and also irregularly across the width of the substrate. According to the present invention, this change in the crowning of the roll is determined by means of sensors distributed across the width of the roll. In order to aim for a constant thickness of the flat substrate across the width, heat and/or cold is applied to the roller from the outside via the temperature control device until the sensors report again that the desired crowning has been achieved again. For an additional check, another bar-like measuring device can be assigned downstream of the flat substrate, which checks the thickness of the substrate across the width.

According to the present invention, characteristic curves are created from the current results and changes with regard to certain flat substrates, which control and support the work of the sensors and the temperature control device. This is always done with the aim of achieving a predetermined thickness of the flat substrate that is uniform across the width.

A corresponding device according to the invention, for which protection is also sought separately, is primarily characterized in that the roller is assigned heating and/or cooling elements distributed over the width of the roller, with which the roller can be temperature-controlled from the outside.

A great advantage of temperature control from the outside is that only the outer area of the roller has to be subjected to heat or cold, with the crowning being significantly influenced by this outer area. This temperature control can also take place very specifically and quickly, which is why the temperature control device consists of a plurality of heating and/or cooling elements.

Furthermore, it is of course a great advantage that the roller itself can be temperature-controlled on the inside, independently of the outside temperature. In this way, the temperature of the roll can be adjusted independently to the corresponding process requirements.

A large number of possibilities are conceivable for the arrangement of these heating and/or cooling elements, which should be covered by the invention. A beam-like arrangement in a row across the width of the roll is primarily intended. In this case, heating elements and cooling elements can alternate, so that areas of the roller which are usually heated can also be covered by means of the cooling elements. In addition, two adjacent heating elements are thereby decoupled from one another, so that their heat input into the roller surface does not add up. However, it is also possible, for example, to separate three adjacent heating elements by a cooling element. This makes it possible, for example, for a heating register made up of three heating elements to introduce more heat into the roller surface than a heating register adjacent to the cooling element, also made up of three heating elements, but in which only one heating element emits heat. In this way, the heat and/or cooling input into the roll surface can be regulated very precisely, and thus also the crowning of the roll can be determined very precisely.

Of course it is also conceivable that several temperature control devices are arranged around the circumference of the roller. An offset of the temperature control elements or the individual heating and/or cooling elements is also conceivable.

The sensors for determining the crowning of the roll are of course preferably arranged at a suitable position between the individual temperature control elements, but are preferably arranged in a line across the width of the roll.

A special configuration of the roll could make crowning even easier. This provides that the roller is not formed from solid material, but rather separates a roller shell from a thick core, with an additional insulating layer being able to be inserted between the roller shell and thick core. This makes it possible to produce or correct a crown more quickly, since the roll shell reacts more quickly to heat input. Above all, a reduction in crowning by cooling is accelerated.

Another advantage is when the surface of the roller is designed to be low-reflection, i.e. it absorbs heat more quickly because it does not reflect the heat applied, or only slightly. For example, the surface of the roller could be black chrome.

character list

• 1 eine schematisch dargestellte Seitenansicht einer erfindungsgemässen Vorrichtung zum Herstellen eines flächigen Substrats;
• 2 eine schematisch dargestellte Draufsicht des oberen Teils der Vorrichtung gemäss 1;
• 3 eine perspektivische Ansicht des Teils der Vorrichtung gemäss 2;
• 4 eine schematisch dargestellte Seitenansicht eines weiteren Ausführungsbeispiels einer erfindungsgemässen Vorrichtung zum Herstellen eines flächigen Substrats;
• 5 eine Frontansicht eines oberen Teils der Vorrichtung gemäss 4.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing; this shows in

• 1 a schematically illustrated side view of a device according to the invention for producing a flat substrate;
• 2 a schematically illustrated plan view of the upper part of the device according to 1 ;
• 3 a perspective view of the part of the device according to 2 ;
• 4 a schematically illustrated side view of a further exemplary embodiment of a device according to the invention for producing a flat substrate;
• 5 a front view of an upper part of the device according to FIG 4 .

A device P according to the invention for producing a flat substrate is described in 1 an upper roller 1 is shown which, together with a lower roller 2, forms a nip 3 through which a flat substrate 4 runs. This flat substrate 4 can be a film, for example.

Roller axes A run through the rollers 1 and 2 centrally, with the rollers 1 and 2 rotating about these roller axes A. The rollers 1 and 2 are mounted on stub shafts 5.

For the top roller 1 is in 1 indicated by a dashed line that here an inner thickness core 6 of the roll 1 is associated with a roll jacket 7 . The dashed line 8 is intended to represent an insulating layer.

Furthermore, a temperature control device 9 is provided above the roller 1, which is curved in accordance with the roller jacket 7. In 2 It can also be seen that this temperature control device consists of a large number of heating and/or cooling elements 10 which are arranged next to one another in a row across the width of the roller 1. Also in 3 are they clearly recognizable.

In 3 It is also shown that sensors 11 are arranged above the roll 1, which determine the surface configuration and in particular the crowning or the bending line of the roll 1 along a width of the roll 1 indicated by dashed lines.

• In vielen Fällen ist es notwendig, dass bei der Herstellung eines flächigen Substrats die Dicke des Substrats sehr genau eingehalten werden muss. Dabei ist aber zu berücksichtigen, dass sich die Temperaturen in der Vorrichtung und
• insbesondere die Temperatur der Walzen 1 und 2 sowie auch des Substrats 4 verändern. Dies führt über die Zeit gesehen auch zu einer Änderung der Dicke des flächigen Substrats, wobei sich die Dicke auch über die Breite des Substrats unterschiedlich verändern kann. Dies soll erfindungsgemäss durch entsprechende Änderung der Bombierung von einer Walze 1 oder von beiden Walzen 1 und 2 ausgeglichen werden.

The operation of the present invention is as follows:

• In many cases it is necessary that the thickness of the substrate must be maintained very precisely when producing a flat substrate. However, it should be noted that the temperatures in the device and
• in particular, the temperature of the rollers 1 and 2 as well as the substrate 4 change. Viewed over time, this also leads to a change in the thickness of the planar substrate, with the thickness also being able to change differently over the width of the substrate. According to the invention, this is to be compensated for by a corresponding change in the crowning of one roll 1 or of both rolls 1 and 2 .

This means that the initial adjustment of the roller gap 3 to a desired thickness of the substrate takes place on the basis of specialist knowledge or characteristic curves. If a change in the thickness of the substrate is detected, the temperature control device is addressed via a corresponding control. The individual tempering elements, which consist of heating and/or cooling elements 10, are now given the command to heat or cool the surface of the roll 1 or 2 accordingly, so that the crowning of the roll changes. This change is continuously determined by the sensors 11 and their value is compared with the achieved changes in the thickness of the flat substrate, which is determined separately in a downstream control device across the width of the substrate. In this case, the regulation is preferably designed as artificial intelligence, which generates characteristic curves from the determined parameters and changes, which are continuously adapted.

In the 4 and 5 a somewhat modified device P1 for producing a flat substrate 4 is shown. The changes do not relate to rollers 1 and 2, but to the temperature control device 9.1. This consists of a plurality of heating and cooling elements 10, which are arranged offset about the axis A of the roll 1 around its circumference in series across the width of the roll. The sensors 11 for determining the crowning of the roll 1 can then be arranged in corresponding spaces 12 between the heating and/or cooling elements. However, the functioning of the two devices P and P1 are the same.

Reference List

1 top roller 34 67 2 bottom roller 35 68 3 nip 36 69 4 substrate 37 70 5 stub shaft 38 71 6 thick core 39 72 7 roller shell 40 73 8th insulating layer 41 74 9 temperature control device 42 75 10 heating and/or cooling element 43 76 11 sensor 44 77 12 space 45 78 13 46 79 14 47 15 48 16 49 A axis 17 50 18 51 19 52 20 53 21 54 22 55 P contraption 23 56 24 57 25 58 26 59 27 60 28 61 29 62 30 63 31 64 32 65 33 66

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 69115339 T2 [0003]
• DE 68906175 T2 [0003]
• DE 102004035630 A1 [0004]
• US 3182587 [0005]
• DE 2713917 A1 [0006]

Claims (17)

Method for producing a flat substrate (4), in particular a film made of one or more layers, by means of at least one roller (1, 2), via which a thickness of the flat substrate (4) is determined over its width, characterized in that - the roller (1) is subjected to heat and/or cold from the outside by a temperature control device (9) arranged across the width of the roller (1); - a crowning of the roller (1) is determined by means of sensors (11) distributed over the width of the roller (1); - when changing the thickness of the substrate (4), the temperature control device (9) for the purpose of changing the crowning of the roller (1) applies heat and/or cold to the roller (1) from the outside in a controlled manner until the crowning has reached the desired thickness of the Substrate (4) generated. procedure after claim 1 , characterized in that characteristic curves for the temperature control device (9) are generated from the determined results, in particular the design of the crowning of the roller (1) over its width and the change in the thickness of the substrate (4) in relation to time known bending lines of the roller (1) are included. procedure after claim 1 or 2 , characterized in that the crowning of the roller (1) is determined by sensors (11) from the outside. Method according to at least one of the preceding claims, characterized in that the determination of the crowning of the roller (1) is carried out capacitively by the sensors (11). Method according to at least one of the preceding claims, characterized in that the flat substrate (4) is produced by at least two rollers (1, 2) which together form a nip (3) through which the substrate (4) is passed. procedure after claim 5 , characterized in that the forces acting in the roll gap (3) are determined and included in the regulation for changing the crowning of the roll (1) and also in the creation of the characteristic curves. Device for producing a flat substrate (4), in particular a film made of one or more layers, by means of at least one roller (1, 2), via which a thickness of the flat substrate (4) is determined over its width, characterized in that the roller (1) is assigned a temperature control device (9) which is arranged across the width of the roller (1) and can be used to control the temperature of the roller (1) from the outside. device after claim 7 , characterized in that the temperature control device (9) consists of a plurality of heating and / or cooling elements (10). device after claim 7 or 8th , characterized in that the heating and/or cooling elements (10) are arranged in series across the width of the roll (1). device after claim 9 , characterized in that several rows of heating and/or cooling elements (10) are arranged over the circumference of the roller (1). Device according to at least one of Claims 7 or 10 , characterized in that the heating and/or cooling elements (10) are arranged offset over the circumference of the roller (1). Device according to at least one of Claims 7 - 11 , characterized in that the roller (1) is assigned at least one sensor (11) for determining the thickness of the roller (1) or the change in the thickness of the roller (1). device after claim 12 , characterized in that several sensors (11) are distributed over the width of the roller (1). Device according to at least one of Claims 7 - 13 , characterized in that the roller (1) has a roller jacket (7) spaced apart from a thick core (6) of the roller (1). device after Claim 14 , characterized in that an insulating layer (8) is provided between the thickness core (6) and the roll shell (7). Device according to at least one of Claims 7 - 15 , characterized in that the surface of the roller (1) is designed to be low-reflection. device after Claim 16 , characterized in that the surface of the roller (1) is black chrome-plated.

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