FILM INSTALLATION AND METHOD FOR PRODUCING A FILM WEB AND USE OF A ROLL APPARATUS WHICH PROCESSES FILM MATERIAL MELT

Abstract

The invention relates to a film installation and a method for producing a film web, in particular a cast film installation or smoothing calender installation, having: a machine direction in which the film web is conveyed through the film installation; a roll apparatus which processes a film material melt and comprises at least one film-producing roll and a film-producing gap having temperature control apparatuses for thermally treating the film web; and a stretching apparatus for stretching the film web, wherein the stretching apparatus is situated downstream of the at least one film-producing roll in the machine direction, circumventing a critical cooling section. The invention further relates to the use of a roll apparatus which processes film material melt.

Claims

1. Film installation for producing a film web, in particular cast film installation or smoothing calender installation, having a machine direction in which the film web is conveyed through the film installation, having a roll apparatus which processes a film material melt and comprises at least one film-producing roll or a film-producing gap, having temperature control apparatuses for thermally treating the film web and a stretching apparatus for stretching the film web, characterized in that the stretching apparatus is arranged downstream of the at least one film-producing roll, circumventing a critical cooling section in the machine direction.

2. Film installation according to claim 1, characterized in that a distance and/or a transfer distance between the at least one film-generating roll and an input roll of the stretching apparatus is less than 1000 mm or less than 800 mm, preferably 500 mm or less.

3. Film installation according to claim 1, characterized in that a distance and/or a transfer distance between the at least one film-producing roll and an input roll of the stretching apparatus is more than 200 mm or more than 250 mm, preferably more than 450 mm.

4. Film installation according to claim 1, characterized in that the stretching temperature required for a stretching process which can be carried out on the stretching apparatus can be generated in its entirety or at least at 50%, preferably at least to 80% or more, by means of the roll apparatus processing a film material melt.

5. Film installation according to claim 1, characterized in that the stretching apparatus is arranged downstream of the film-generating roll in the machine direction in such a way that the film web leaving the at least one film-generating roll can be transferred directly to the stretching apparatus.

6. Film installation according to claim 5, characterized in that the stretching apparatus comprises a film web removal roll by means of which the film web can be removed directly from the film-producing roll.

7. Film installation according to claim 1, characterized in that the stretching apparatus is arranged downstream of the film-generating roll in the machine direction in such a way that the film web leaving the film-generating roll can be transferred first to a pre-temperature control apparatus and then to the stretching apparatus.

8. Film installation according to claim 1, characterized in that the stretching apparatus comprises at least one temperature-controllable stretching roll.

9. Film installation according to claim 8, characterized in that the pre-temperature control apparatus comprises at least one film pre-temperature control roll, by means of which the film web can be pre-tempered at a temperature above 70° C., preferably between 90° C. and 120° C.

10. Method for producing, in particular for casting-rolling or smooth-rolling, a film web, in which a film material melt is supplied to a relevant roll apparatus which processes a film material melt having at least one film-producing roll and/or a film-producing gap, and this film material melt is formed into the film web by means of the at least one film-producing roll and/or the film-producing gap, and in which the film web is subsequently supplied to different temperature control apparatuses and to at least one stretching apparatus, in particular for operating a film installation according to claim 1, characterized in that the stretching temperature required for a stretching process which can be carried out at the stretching apparatus is generated in its entirety or at least at 50%, preferably at least at 80% or more, by means of the roll apparatus 4 which processes a film material melt.

11. Method for producing, in particular for casting-rolling or smooth-rolling, a film web, in which a film material melt is supplied to a roll apparatus processing a film material melt in this respect having at least one film-producing roll and/or a film-producing gap, and this film material melt is formed into the film web by means of the at least one film-producing roll and/or the film-producing gap, and in which the film web is subsequently supplied to different temperature control apparatuses and at least one stretching apparatus, in particular for operating a film installation according to claim 1, characterized in that the film web is stretched from the film material melt exclusively with the aid of the heat.

12. Method according to claim 11, characterized in that the film web is stretched in addition to the heat from the film material melt by means of heat from the roll apparatus processing a film material melt and the stretching apparatus.

13. Method for producing, in particular for casting-rolling or smooth-rolling, a film web, in which a film material melt is supplied to a relevant roll apparatus which processes a film material melt having at least one film-producing roll and/or a film-producing gap, and this film material melt is formed into the film web by means of the at least one film-producing roll and/or the film-producing gap, and in which the film web is subsequently supplied to different temperature control apparatuses and at least one stretching apparatus, characterized in that the film web, after leaving the at least one film-generating roll and/or the film-generating gap, is stretched by a stretching apparatus, circumventing further temperature control apparatuses.

14. Method for producing, in particular for casting-rolling or smooth-rolling, a film web, in which a film material melt is supplied to a roll apparatus which processes a film material melt having at least one film-producing roll and/or a film-producing gap, and this film material melt is formed into the film web by means of the at least one film-producing roll and/or the film-producing gap, and in which the film web is subsequently supplied to different temperature control devices and at least one stretching apparatus, characterized in that the film web, after leaving the at least one film-generating roll and/or the film-generating gap, is supplied to a pre-temperature control apparatus and is subsequently transferred from the pre-temperature control apparatus directly to a stretching apparatus, by means of which the film web is stretched.

15. Use of a roll apparatus which processes a film material melt for heating a film web to stretching temperature for a stretching process directly following the roll apparatus which processes the film material melt on a film installation which produces a film web.

Description

[0117] In the drawing,

[0118] the single FIGURE schematically shows a model view of a film installation for producing a film web with a stretching apparatus arranged downstream of a roll apparatus melt-processing a film material while circumventing a critical cooling section in the machine direction.

[0119] The film installation 1 shown in FIG. 1 is used for the production of films 2, which is designed here as an example as a flat film (not numbered separately).

[0120] Such film installations 1 can be designed in a wide variety of ways, for example as a cast film installation 3, as shown schematically according to the representation in the single FIGURE, as a smoothing installation (not shown) or the like.

[0121] The cast film installation 3 shown differs in the sense of the invention from a smoothing calender installation not shown, for example, essentially by a casting roll 4, which is placed on the input side or at the input 5 of the film installation 1, in contrast to smooth rolls (not shown) of a smoothing calender installation which form a roll gap (not shown).

[0122] In any case, the film installation 1 shown in the single FIGURE is a cast film installation 3 with a casting roll 4, which is connected downstream of an extruder device 6 for producing a film material melt 7, the extruder device 6 being shown by way of example only with regard to a wide spray nozzle 8, by means of which the film material melt 7 is applied to the roll surface 10 of the casting roll 4 in the form of a film material melt vane 9.

[0123] By means of the casting roll 4, the film material melt vane 9 is formed into a film web 11.

[0124] The casting roll 4 is a chromium-plated steel roll (not specified again) with a diameter of 1000 mm, which can be heated to at least 120° C. on the roll surface 10 at a temperature difference of +1-1° C. The casting roll 4 rotates about its casting roll axis 16 in a direction of rotation 15. The film web 11 can be guided around the casting roll 4 at an angle of wrap of at least 220°.

[0125] With the aid of the casting roll 4, the film material melt 7 is cooled to below a recrystallization temperature of the film material melt 7 or is kept in a range of this recrystallization temperature of the film material melt 7, the recrystallization temperature being dependent on the respective plastic film material to be processed.

[0126] In any case, the film installation 1 with the casting roll 4 already described above comprises a roll apparatus 18 which processes a film material melt 7 with at least one film-producing roll 19, namely the casting roll 4 in this embodiment.

[0127] Furthermore, the film installation 1 also comprises both a stretching apparatus 20 and temperature-control apparatuses 22, 23 and 24 for thermally treating the film web 11, the film web 11 being meanderingly transported through the film installation 1 in the machine direction 26 by the roll apparatus 18 processing film material melt 7, here in particular in the form of the casting roll 4.

[0128] In the embodiment shown in the single FIGURE, the first temperature-control apparatus 22 is a pre-temperature-control apparatus 28, which is connected directly downstream of the casting roll 4 and thus of the roll apparatus 18 which processes the film material melt 7 in the machine direction 26. The pre-temperature-control apparatus 28 has two corresponding pre-temperature control rolls 29 and 30, both of which are chromium-plated steel rolls with a diameter of 310 mm. The two pre-temperature control rolls 29 and 30 can be tempered in such a way that temperatures of 90° C. to 110° C. can be set on their respective roll surfaces (no longer explicitly quantified). The two pre-temperature control rolls 29 and 30 are also characterized by a wrap angle of at least 160°. Furthermore, they can be driven individually, whereby a lead can be set on the pre-temperature control apparatus 28.

[0129] The first temperature control apparatus 22 or the pre-temperature control apparatus 28 is essentially used for uniform temperature control of the film web 11 to stretching temperature, the stretching temperature preferably being above the respective recrystallization temperature of the film material melt 7.

[0130] In this embodiment, the second temperature control apparatus 23 is designed as a temperature control apparatus 32, which comprises two temperature-controlled rolls 33 and 34, the temperature-controlled rolls 33 and 34 each being designed as a chromium-plated steel roll with a diameter of 310 mm. The temperature-controlled rolls 33 and 34 are arranged relative to one another in such a way that they each provide a wrap angle of 220° for the film web 11. A lead can also be set on the temperature-controlled apparatus 32.

[0131] By means of the temperature-controlled apparatus 32, the film web 11 or the film material is briefly tempered below the melting temperature of the film material in order to remove residual stresses in the film 2 or the film web 11 by introducing tensile stress into the film web 11.

[0132] For this purpose, the first temperature-controlled roll 33 and the second temperature-controlled roll 34 can be heated in such a way that they can be operated with surface temperatures of approximately 100° C. to 110° C.

[0133] The temperature-controlled rolls 33 and 34 are often also referred to as annealing rolls.

[0134] Furthermore, the film installation 1 according to the embodiment shown comprises, with respect to the third temperature-controlled apparatus 24, a cooling device 36 which, viewed in the machine direction 26, is connected immediately downstream of the temperature-controlled apparatus 32, wherein by means of the cooling device 36 the film web 11 is cooled down to almost ambient temperature only at this point in time, as a result of which the orientation of the film material molecules is ultimately “frozen” only at the cooling device.

[0135] For this purpose, the cooling device 36 in this embodiment comprises two cooling rolls 37 and 38, which in turn are designed as chromium-plated steel rolls, each with a diameter of 310 mm.

[0136] The temperature of the two cooling rolls 37 and 38 can be adjusted in such a way that a maximum surface temperature of 100° C. can be provided at their respective roll surfaces.

[0137] The cooling rolls 37 and 38 are arranged opposite one another in such a way that they each ensure a wrap angle of at least 220° for the film web 11.

[0138] In addition, the stretching apparatus 20 has two stretching roll groups 40 and 41, at least in this embodiment. Each of the stretching roll groups 40 or 41 consists of a first pair of stretching roll contact rolls 42 or 43 and an auxiliary roll 44 or 45.

[0139] The first pair of stretching rolls and contact rolls 42 has a rubberized stretching roll 46 and a corresponding contact roll 47.

[0140] Accordingly, the second pair of stretching rolls and contact rolls 43 also has a rubberized stretching roll 48 and a contact roll 49 corresponding thereto.

[0141] While the first and second stretching rolls 46 and 48 each comprise a rubberized steel roll with a diameter of 210 mm, the first and second contact rolls 47 and 49 each comprise a chromium-plated steel roll with a diameter of 210 mm.

[0142] At least one of the two stretching rolls 46 or 48 can be tempered, preferably in such a way that a surface temperature of around 120° C. can then be set on the respective stretching roll 46 or 48.

[0143] Furthermore, the individual roll-contact roll pairs 42 and 43 are driven individually, so that a stretching factor or a lead is preferably continuously adjustable at the stretching apparatus 20.

[0144] Racking or stretching of film 2 or of film web 11 at a ratio of 1:4 can be achieved by means of stretching apparatus 20.

[0145] Furthermore, the stretching apparatus 20 has a stretching gap length 50, which is preferably adjustable.

[0146] It is advantageous if the stretching gap length 50 is as small as possible so that the stretching apparatus 20 is as compact as possible and, in particular, the risk is reduced that film web 11 cools down unfavorably inside the stretching apparatus 20 or between the two pairs of stretching roll contact rolls 42 and 43 of the stretching apparatus 20.

[0147] The two auxiliary rolls 44 and 45 have a substantially smaller diameter than the stretching rolls 46 and 48, respectively, and the contact rolls 47 and 49, respectively, but are also each formed by a chromium-plated steel roll.

[0148] Advantageously, in the embodiment shown in the single FIGURE, the film installation 1 is set up in such a way that the stretching apparatus 20 is arranged downstream of the at least one film-producing roll 19 or the casting roll 4 in the machine direction 26, circumventing a critical cooling section 53.

[0149] According to the representation according to the single FIGURE, the critical cooling section 53 is shown and drawn only symbolically in order to illustrate its position schematically within the present film installation 1.

[0150] In this embodiment, it corresponds to a transfer section 54 in which the film web 11 is guided between the casting roll 4 and an input roll 58 of the stretching apparatus 20.

[0151] In a very simple case (not shown here), the input roll 58 may at the same time embody a film web removal roll 60, by means of which the film web 11 can be removed from the casting roll 4.

[0152] In other words, this means that the stretching apparatus 20 is arranged opposite the roll apparatus 18 processing film material melt 7 or its film-producing roll 19 or, in particular, the present casting roll 4 in such a way that the risk of unintentional critical cooling of the film web 11 on the transfer section 54 can ideally be excluded after the film web 11 leaves the roll apparatus 18 processing film material melt 7 and reaches the stretching apparatus 20 or the input roll 58 of the stretching apparatus 20.

[0153] For the purposes of the present invention, the term “critical cooling section” describes a section (transfer section 54) running essentially in the machine direction 26, which the film web 11 covers from the film-producing roll 19 to the input roll 58 of the stretching apparatus 20, whereby this section can run in a straight line or, as shown in this embodiment according to the single FIGURE, can have a number of curves.

[0154] In the sense of the invention, the term “critical cooling section” further describes a section in which the film web 11 can cool to below a stretching temperature of the respective film web material or of the respective film web 11 up to now in the prior art, the respective stretching temperature also being dependent on the respective film material used.

[0155] The critical cooling section 53 or the transfer section 54 begins with the detachment of the film web 11 from the film-producing roll 19 or the casting roll 4 of the roll apparatus 18 which processes the film material melt 7.

[0156] The critical cooling section 53 or the transfer section 54 therefore ends with the contact of the film web 11 with the stretching apparatus 20 or, in particular, with the input roll 58 of the stretching apparatus 20.

[0157] According to a very simple embodiment of the present invention or of the film installation 1, a critical cooling section 53 in the sense of the present invention can be avoided, if the input roll of the stretching apparatus immediately represents a film web removal roll 60, by means of which the film web 11 can be directly removed from the film-producing roll 19. However, this is not the case in the embodiment of the film installation 1 shown in the single FIGURE, since the pre-temperature control apparatus 28 is still placed between the stretching apparatus 20 and the roll apparatus 18 which processes the film material melt 7. If such a pre-temperature control apparatus 28 was dispensed with in an alternatively designed film installation 1, the input roll 58 of the stretching apparatus 20 already described above would take over the film web removal roll 60.

[0158] However, in order to avoid the risk of an embodiment of a critical cooling section 53 on the film installation 1 in the sense of the invention, the stretching apparatus 20 is arranged opposite the roll apparatus 18 processing film material melt 7 in such a way that the distance 62, in particular between the film-producing roll 19 or casting roll 4 and the input roll 58 (film web removal roll 60) of the stretching apparatus 20, is less than 1000 mm or less than 800 mm, preferably less than 500 mm or 100 mm.

[0159] In order for the pre-temperature control apparatus 28 to still find space between the casting roll 4 and the input roll 58, the distance 62 in the embodiment according to the single FIGURE is less than 1000 mm but more than 800 mm.

[0160] According to the embodiment shown in the single FIGURE, critical cooling of the film web 11 during transfer from the roll apparatus 18 processing the material melt 7 to the stretching apparatus 20 is prevented by the pre-temperature control apparatus 28 arranged in between them.

[0161] In other words, this means that a critical cooling path 53 in the sense of the invention exists neither between the pre-temperature control apparatus 28 and the roll apparatus 18 processing the film material melt 7 nor between the pre-temperature control apparatus 28 and the stretching apparatus 20.

[0162] In this respect, the film system 1 according to the embodiment of the single FIGURE is set up in such a way that the stretching apparatus 20 is arranged downstream of the film-producing roll 19 or casting roll 4 in the machine direction 26 in such a way that the film web 11 leaving the film-producing roll 19 or casting roll 4 is transferred to the pre-temperature control apparatus 28 and then to the stretching apparatus 20.

[0163] The advantage of the stretching apparatus 20 being arranged downstream of the at least one film-producing roll 19, circumventing a critical cooling section 53 in the machine direction 26, is to be seen in the fact that the film web 11 is stretched exclusively with the aid of the heat from the film material melt 7.

[0164] In this respect, the stretching temperature required for a stretching process which can be carried out at the stretching apparatus 20 is generated here entirely or at least up to 80% by means of the roll apparatus 18 processing a film material melt 7.

[0165] In other words, this means that, in the sense of the invention, stretching is carried out exclusively with the aid of the heat inherent in the film material or film web 11.

[0166] This advantageously avoids cooling of the film material of the film web 11 below a still reasonable stretching temperature.

[0167] It is understood that the heat from the roll apparatus 18 processing the film material melt and from the stretching apparatus 20, which may also have an additional thermal effect on the film material or the film web 11, is negligible.

[0168] Depending on the film material from which the film 2 or the film web 11 to be produced is to be produced or on the type of film 2 or film web 11 involved, it is advantageous for the film web 11 to be supplied to a pre-temperature control apparatus 28 after leaving the at least one film-producing roll 19 and then transferred from the pre-temperature control apparatus 28 directly to the stretching apparatus 20, as shown according to the single FIGURE.

[0169] By means of the pre-temperature control apparatus 28, however, it is very well possible to equalize the temperature or the heat within the film web 11 as much as possible, whereby the racking or stretching quality of the immediately following stretching process can be increased even further.

[0170] At this point, it should be explicitly pointed out that features of the solutions described above or in the claims and/or the single FIGURE can also be combined, if necessary, in order to be able to implement or achieve the explained features, effects and advantages correspondingly cumulatively.

[0171] It is understood that the embodiment explained above is only a first embodiment of a film installation according to the invention. In this respect, the embodiment of the invention is not limited to this embodiment.

[0172] All features disclosed in the application documents are claimed to be essential to the invention, insofar as they are novel, individually or in combination with each other, over to the prior art.

LIST OF REFERENCE SIGNS USED

[0173] 1 Film installation [0174] 2 Films [0175] 3 Cast film installation [0176] 4 Casting roll [0177] 5 Entry [0178] 6 Extruder device [0179] 7 Film material melt or plastic melt [0180] 8 Wide spray nozzle [0181] 9 Film material melt vane [0182] 10 Roll surface [0183] 11 Film web [0184] 15 Direction of rotation [0185] 16 Casting roll axis [0186] 18 Roll apparatus [0187] 19 Film-producing roll [0188] 20 Stretching apparatus [0189] 22 First temperature control apparatus [0190] 23 Second temperature control apparatus [0191] 24 Third temperature control apparatus [0192] 26 Machine direction [0193] 28 Pre-temperature control apparatus [0194] 29 First pre-temperature control rolls [0195] 30 Second pre-temperature control roll [0196] 32 Temperature control apparatus [0197] 33 First temperature control roll [0198] 34 Second temperature control roll [0199] 36 Cooling device [0200] 37 First cooling roll [0201] 38 Second cooling roll [0202] 40 First group of stretching rolls [0203] 41 Second group of stretching rolls [0204] 42 First pair of stretching roll contact rolls [0205] 43 Second pair of stretching roll contact rolls [0206] 44 First auxiliary roll [0207] 45 Second auxiliary roll [0208] 46 First stretching roll [0209] 47 First contact rolls [0210] 48 Second stretching roll [0211] 49 Second contact rolls [0212] 50 Stretching gap length [0213] 53 Cooling section [0214] 54 Transfer section [0215] 58 Input roll [0216] 60 Film web removal roll [0217] 62 Distance