EP3433066A1

EP3433066A1 - Calender stack and method for calendering a plastic film

Info

Publication number: EP3433066A1
Application number: EP17706720.4A
Authority: EP
Inventors: Andreas Friesen; Joachim Thole
Original assignee: KraussMaffei Berstorff GmbH
Current assignee: KraussMaffei Extrusion GmbH
Priority date: 2016-03-21
Filing date: 2017-02-21
Publication date: 2019-01-30
Also published as: US20190099935A1; TW201741110A; DE102016105178A1; CN109311192A; KR20180121974A; WO2017162387A1; DE102016105178B4

Abstract

The invention relates to a calender stack for an extruded material web (51) made from thermoplastic, in particular a film web, having (a) a stand (1) which has (i) a first guide rail set (2) which comprises two arcuate first guide rails (2', 2'') and (ii) a second guide rail set (3) which comprises two arcuate second guide rails (3', 3''), (b) a first calender roll (8) which can be rotated about a first calender roll rotational axis (D8) and is mounted on the stand (1), (c) a second calender roll (9) which forms a calender with the first calender roll (8) and is fastened to the stand (1), (d) an adjusting roll (14) which can be rotated about an adjusting roll rotational axis (D₁₄) and is mounted on the stand (1), and (e) a supporting device (34), on which the stand (1) is mounted rotatably in such a way that the first calender roll rotational axis (D₈) remains stationary during a rotation of the stand (1). According to the invention, the stand (1) is configured in such a way that the adjusting roll (14) can be positioned at an angle of inclination (α) of at least 55°, wherein the angle of inclination (α) is formed firstly between a horizontal which runs perpendicularly with respect to the first calender roll rotational axis (D₈) and through the first calender roll rotational axis (D₈), and secondly a straight line which runs perpendicularly with respect to the first calender roll rotational axis (D₈) through the first calender roll rotational axis (D₈) and through the adjusting roll rotational axis (D₁₄).

Description

GLOSSY WORK AND METHOD FOR THE SMOOTHING OF A PLASTIC FOIL

The invention relates to a calender for an extruded thermoplastic material web, in particular a film web, comprising (a) a stand comprising (i) a first guide rail set comprising two arcuate first guide rails, and (ii) a second guide rail set comprising (b) a first calender roll which is rotatable about a first calender roll rotation axis and supported on the stand, (c) a second calender roll which forms a calender with the first calender roll and is attached to the stand or is mounted, (d) an adjusting roller which is rotatable about a Verstellwalzen rotation axis and is mounted on the stand, and (e) a support device on which the stator is rotatably mounted so that upon rotation of the stator, the first Kalanderwalzen- rotation axis remains stationary.

Such a calender is known from DE 197 52 524 A1. A disadvantage of this calender is that it is only limited possible to produce transparent films with a particularly high degree of transparency.

The invention has for its object to provide a calender, by means of which the transparency of the film can be increased.

The invention solves the problem by a generic calender, in which the stand is designed so that the adjusting roller, in particular automatically, can be positioned at an angle of inclination of at least 55 °, wherein the angle of inclination is formed between a horizontal perpendicular to the first calender roller Rotary axis and through the first calender roller axis of rotation runs, on the one hand and a straight line which is perpendicular to the first calender roller axis of rotation and through the first calender roller axis of rotation and by the adjusting roller axis of rotation, on the other. In this way, a small wrap angle of less than 90 ° can be achieved even if a second calender roll rotation axis of the second calender roll and the first calender roll rotation axis are at the same height. This is particularly the case when the second calender roll axis of rotation and the first calender roll axis of rotation lie in a horizontal plane, for example to produce thin films. The wrap angle is the angle over which the material web rests against the first calender roll. The first calender roll is preferably tempered, in particular cooled, so that the material web cools all the more, the greater the wrap angle. Therefore, it would actually have been expected that a large wrap angle would be advantageous. However, it has been found that the thermal conductivity of the material web is usually so small that the first calender roll is only able to cool the side of the material web which faces away from the first calender roll. It has therefore been found to be positive to choose a smaller wrap angle. However, the known calender is not able to set sufficiently small angles of wrap for all positions of the adjusting roller and / or the second calender roller.

The smoothing unit according to the invention is able to adjust small angles of wrap of less than 90 °, in particular less than 80 °, so that the material web can be directed after a short time from the first calender roll to the adjusting roller. The adjustment roller is also cooled according to a preferred embodiment, so that the material web is cooled rapidly from both sides. This leads to a particularly rapid drop below the glass transition temperature and thus to a high transparency of the material web.

According to a preferred embodiment, the calender has a drive unit which cooperates positively with a toothing, which is formed on the stand, so that the stand is automatically rotatable. In this way, a position of the second calender roll in the room can be automatically adjusted. It should be noted that the first calender roll rotation axis of the first calender roll does not move in space when the stand is moved by the drive unit. This is to be understood that the position of the first calender roll axis of rotation does not change in the technical sense. While it is possible that during the movement of the stator to a measurable change of the first calender roll axis of rotation comes, but this is so small that it is irrelevant to the function of the first calender roll.

Preferably, the first guide rail set comprises a first auxiliary guide rail, wherein the second guide rail set has a second additional rail and wherein one of the first guide rails is part of a rotary guide for rotating the stator and on another of the guide rails a carriage is guided by means of the adjusting roller is movably mounted on a circular arc on the stand, wherein the center of the circular arc coincides with the first calender roller rotation axis. By the feature that the center of the circular arc coincides with the first calender roll axis of rotation, it is understood in particular that although it is possible and preferred that the center lies exactly on the first calender roll axis of rotation, this is not necessary. In particular, the center of the circular arc may be at a distance from the first calender roll rotation axis, for example less than 50 micrometers.

The term of the additional guide rail is to be understood that this rail is not known from the prior art. In particular, it does not mean that it could be optional.

Preferably, the second calender roll is fixedly connected to the stand. Alternatively, it is possible that the adjusting roller is mounted by means of a second carriage on the stand on a circular arc movable. In this case, it is dispensable that the stand itself is designed to be movable. Under the feature that the adjusting roller is movably mounted on the arc by means of the carriage on the arc, is in particular understood that the adjusting roller is guided by the carriage on the stand on a circular arc.

It is favorable if the toothing is formed on at least one guide rail. It is particularly favorable if the toothed guide rail is fastened to the remaining part of the stand, in particular detachably fastened. For example, the toothed guide rail is screwed to the remaining part of the stand and / or riveted. This has the advantage that the toothing can be made very easy. In addition, the teeth can be easily adjusted relative to the rest of the stand.

It is advantageous if the first calender roll and / or the adjusting roll are connected to a cooling device for cooling the rolls. The cooling device is part of the calender.

According to the invention, there is also a film production apparatus with an extruder for producing an extruded material web, in particular a film web, made of thermoplastic material and a calender unit according to the invention, which are arranged in a material flow path. direction of the web behind the extruder for smoothing the web is arranged. By way of example, the extruder comprises a slot die for producing the extruded material web.

According to the invention is also a method for producing films with the steps of (i) producing an extruded material web of thermoplastic material and (ii) smoothing the material web with a calender invention, wherein a wrap angle is smaller than 85 °, in particular 75 °. The wrap angle denotes the angle over which the material web rests against the first calender roll.

Preferably, the first calender roll and / or the adjusting roll are cooled to a temperature which is below a glass transition temperature of the thermoplastic material. It is also beneficial if the temperature is at least 10 Kelvin below this glass transition temperature.

It is particularly advantageous if the thermoplastic is transparent. For example, the plastic is polycarbonate or polyethylene terephthalate.

In the following the invention will be explained in more detail with reference to the accompanying drawings. It shows

Figure 1 is a side view of a calender invention in a first

Alignment position,

FIG. 2 shows a section II - II according to FIG. 1,

Figure 3 is a view of the support device of the calender and

Figure 4 shows the calender in a pivoted relative to Figure 1 position to achieve a particularly small wrap angle.

FIG. 5 shows a perspective detail view of the stand and the carrying device supporting the stand,

Figure 6 shows a full perspective view of the calender and

FIG. 7 shows details of the drive of the stator.

FIG. 1 shows a calender 46 which has a stand 1. 2) which comprises two circular-arc-shaped primary guide rails 2 ', 2 ", The stator also has a second guide rail set 3, which has two circular-arc-shaped second guide rails 3', 3". The two first guide rails 2 ', 2 "are spaced apart from one another and arranged parallel to one another The guide rails 2', 2", 3 'and 3 "extend in a circular arc, that is to say that they extend along a circular arc The two guide rail sets 2, 3 each have a traverse 4, 5, to which they are arranged laterally and which runs in the manner of a chord of a circle, The two guide rail sets 2, 3 are connected to one another.

At the two trusses 4, 5, a first calender roller 8 is rotatably supported by bearings 6, 7. The calender comprises a drive, not shown, by means of which the calender roll 8 is rotationally driven. The calender roll 8 is rotatably mounted about a first calender roll rotation axis D ₈ . Between the two guide rails 2 ', 2 "a- on the one hand and 3 ', 3 "on the other hand, the two guide rail sets 2, 3 are adjustment devices 12, 13 which serve to adjust a second calender roll 9. The second calender roll 9 is mounted in bearings 10, 11 around a second calender roll rotation axis D ₉ The bearings 10, 1 1 hold the second calendering roller 9 and are movable by the adjusting devices 12, 13 (see Figure 2), so that a gap between the first calendering roller 8 and the second calendering roller 9 can be adjusted by means of the adjusting devices 12, 13 Regulating devices 12, 13 may have a motor, but this is not necessary.

The second calender roll 9 is radially adjustable relative to the first calender roll rotation axis D ₈ by means of the adjusting devices 12, 13. The calender 46 also includes an adjustment roller 14, which is mounted by means of guide carriage 15, 16 on a circular arc about the first calender roller rotation axis D ₈ to the guide rail sets 2, 3 pivotally. The adjusting roller 14 is attached to the ends of the guide carriage 15, 16 and adjustably mounted in the radial direction to the first calender roll 8. In this way, the distance between the first calender roller 8 and the adjusting roller 14 can be adjusted.

2 shows that the first guide rail set 2 has a first additional guide rail 2 "'. The second guide rail set 3 has a second additional guide rail 3"'. The guide carriage 15 runs on a guide track 17 which is formed on the first additional guide rail 2 "'and on a guide track 18 which is formed on the first guide rail 2". The second guide carriage 16 runs on a guide track 19 which is formed on the second additional guide rail 3 "'and on a second guide track 20 which is formed on the second guide rail 3". It can be seen that the first guide rail 2 'and the second guide rail 3' has a toothing 23 or 24, but not the other guide rails.

The guideways 17, 18, 19, 20 are circular arc-shaped and the center point of the circular arcs coincides with the first calender roller rotation axis D ₈ .

The carriage 16 has rollers 25, 26, with which it runs on the guideways 19, 20. Outside the carriage 16 is additionally guided over two rollers 27. The guide carriage 15 has a toothed pinion 28, by means of which a position of the guide carriage 15 can be adjusted in the circumferential direction. The pinion 28 is connected by means of a shaft 30 with a further pinion 29 which meshes with the toothing 24. The Shaft 30 is connected to a power drive 31, so that the guide carriage 15, 16 are simultaneously movable. As a result, the adjusting roller 14 is moved on the circular arc.

FIG. 3 shows that the stand 1 rests on supporting wool 36, 37, 38, 39 of a carrying device 34, which in the present case is designed as a supporting frame. The stator 1 is pivotable about the first calender roller rotation axis D ₈ by means of the support device 34. The support rollers 36, 37 are designed with ribs 40, 41, with which they include the guide rail 2 "additionally laterally.

The guide rail 2 "has an outer guide track 21 which is circular arc-shaped, and a center of the circular arc is the first calender roller rotation axis D _8. The pedestal 1 passes over the outer guide track 21 onto the support shaft 36, 37. The second guide rail 3" has a outer guideway 22, with which it rests on the support rollers 38, 39. The calender 46 has a pivot drive 47, the two drive pinion 42, 43 which are mounted on the support frame 43. The two drive pinions 42, 43 are connected by means of a drive shaft 44, which is coupled to a drive unit 45. The drift pin 42, 43 engage in the teeth 23, 24 of the guide rails 2 'and 3'.

The toothed guide rail 3 'is screwed to the second additional guide rail 3 "' by means of schematically drawn screws 48.1, 48.2, 48.3 In the same way, the guide rail 2 'is screwed to the guide rail 2"' by means of screws 49.1, 49.2, 49.3.

FIG. 1 also shows schematically an extruder 50 with its slot die B. In the case shown in FIG. 1, the nozzle exit is directed vertically downwards and the two calender rolls 8, 9 are aligned horizontally with respect to each other in order to receive the material web leaving the slot die B. Purely schematically, a material web 51 is shown with a dashed line. It can be seen that the material web 51 rests with a wrap angle α on the first calender roll 8, for which applies in the present case a = 180 °. Thereafter, the material web 51 is removed by the adjusting roller 14.

Dashed is the adjusting roller, which is marked with 14 ', drawn in a second position, in which the wrap angle a' = 90 °. The dashed line position can not be achieved with calenders of the prior art. The Ver- Adjusting roller 14 is moved from the position indicated by solid lines in the position indicated by dashed lines by the carriages 15, 16 are moved to the guide rails. The extruder 50 and the calender 46 are part of a film production device 52 according to the invention.

An independent subject of the present application is a generic calender, in which the second calender roll and the adjusting roller are mounted so that a wrap angle of <than 90 °, in particular <80 °, is adjustable.

FIG. 5 shows that the first guide rail 2 'is screwed on so that it can be manufactured and mounted particularly easily.

Figure 6 shows a full perspective view of the calender.

FIG. 7 shows the pinions 28, 29, which mesh with the toothing 23.

LIST OF REFERENCE NUMBERS

stand

first guide rail set 'first guide rail

"first guide rail

'"first additional guide rail

second guide rail set

1 second guide rail

second guide rail

'second additional guide rail

, 5 traverse

, 7 Storage

first calender roll

second calender roll

0, 1 1 storage

2, 13 adjusting device

4 adjusting roller

5, 16 carriages

7,18,19,20 inner guideways

1, 22 outer guideways

3, 24 toothing

5, 26, 27 roles

8, 29 pinion

0 wave

1 power drive

2 engine

3 angle gear

4 carrying device

5 wheels

6,37,38,39 carrying roller

0, 41 board

2, 43 driving pinion

4 drive shaft

5 drive unit

6 calender

7 rotary actuator 48, 49 screw

50 extruders

51 material web

52 Film production device α Wrap angle

B wide-slot nozzle

D rotation axis

Claims

claims

Glättwerk for an extruded material web (51) made of thermoplastic material, in particular a film web, with

(a) a stand (1), the

(I) a first guide rail set (2), the two circular arc-shaped first guide rails (2 ', 2 ") comprises, and

(ii) a second guide rail set (3) comprising two circular arc-shaped second guide rails (3 ', 3 "),

having,

(B) a first calender roll (8), the

- Is rotatable about a first calender roll rotation axis (D ₈ ) and

is mounted on the stand (1),

(c) a second calender roll (9), the

- With the first calender roll (8) forms a calender and

- fixed to the stand (1),

(D) an adjusting roller (14), the

- Is about a Verstellwalzen rotation axis (D) is rotatable and

- Is mounted on the stand (1), and

(e) a carrying device (34) on which the stand (1) is rotatably mounted such that upon rotation of the stand (1) the first calender roll rotation axis (D ₈ ) remains stationary,

characterized in that

(F) the stand (1) is formed so that the adjusting roller (14) can be positioned at an angle of inclination (oc) of at least 55 °, wherein the inclination angle (oc) is formed between

a horizontal, which is perpendicular to the first calender roll axis of rotation (D ₈ ) and through the first calender roll axis of rotation (D ₈ ), on the one hand and

a straight line perpendicular to the first calender roll rotation axis (D ₈ ) through the first calender roll rotation axis (D ₈ ) and through the adjustment roll rotation axis (D ₁₄ ), on the other hand.

Glättwerk according to claim 1, characterized by

(a) a drive unit (45),

the form-fitting with a toothing (23, 24) cooperates on the

Stand (1) is formed so that the stand (1) is automatically rotatable, (b) wherein the first guide rail set (2) has a first auxiliary guide rail (2 "') and the second guide rail set (3) has a second auxiliary guide rail (3"'), and

(c) wherein one of the first guide rails (2 ') is part of a rotary guide to the

Turning the stand (1) and at another of the guide rails (2 ",

2 "') a guide carriage (15) is guided, by means of which the adjusting roller (14) on a circular arc whose center coincides with the first Kalanderwalzen- rotational axis (D ₈ ) is movably mounted on the stator (1).

3. calender according to one of the preceding claims, characterized in that the second calender roll (9) is fixedly connected to the stand.

4. smoothing unit according to one of the preceding claims, characterized in that the toothing (23, 24) on at least one guide rail (2 ', 3') is formed.

5. smoothing unit according to claim 4, characterized in that the toothed guide rail (2 ', 3') attached to the remaining part of the stand (1), in particular releasably secured, is.

6. calender according to one of the preceding claims, characterized in that the first calender roll (8) and / or the adjusting roller (14) are connected to a cooling device for cooling the rollers.

7. Film making device (52) with

(I) an extruder (50) for producing an extruded material web (51) made of thermoplastic material and

(Ii) a calender (46) according to any one of the preceding claims, which is arranged in a material flow direction behind the extruder (50) for smoothing the material web (51).

8. Method for producing films with the steps

(i) producing an extruded material web (51) of thermoplastic

Plastic and

(ii) smoothing the material web (51) with a calender (46) according to one of

previous claims,

(iii) wherein an angle of wrap (a) is less than 85 °, in particular 75 °.

9. The method according to claim 8, characterized in that

the first calender roll (8) and / or the adjusting roll (14) are tempered to a temperature which is below a glass transition temperature of the plastic.

10. The method according to claim 8 or 9, characterized in that

the thermoplastic is transparent.