METHOD FOR INDIRECTLY DERIVING A SYSTEMATIC DEPENDENCY BETWEEN A SETTING PARAMETER AND AN OPTICAL PROPERTY OF A FILM WEB, METHOD FOR ADAPTING THE QUALITY OF A FILM WEB

Abstract

The invention relates to the determination of the optical quality of a film. On the one hand, a correlation of the obtained measured values with the production parameters, which are detected in a time-synchronous manner at the extrusion plant, is carried out. On the other hand, a correlation of said obtained measurement data with the geometric and/or functional properties of a film, for example the water vapor permeability, is carried out. The obtained correlation of data is used in the process for controlling the running production process of the film to an optimum operating point. Consequently, the resulting functional properties of a film are improved in an automated manner and met according to the desired specifications. The operator can predetermine which geometric and/or functional properties of a film are accepted as a control variable.

Claims

1.

2.

3. Method for indirectly deriving a systematic dependency in a blown film or cast film production process of a film web between a setting variable of the manufacturing process and an optical property of the produced film web, characterized in that an optical property of the film web is determined as a first parameter of the process inline on the produced film web by means of a sensor, a second parameter of the method is determined, in particular a parameter of the manufacturing device from the production of film web, in particular the setting variable of the production process is determined, a data detection system digitalizes and records the parameters as needed, the determinate parameters are stored in an orderly manner, related to each other and from the, in a data base stored, data the dependence between the parameters is derived systematically.

2. Method according to claim 1, characterized in that the specific dependence of the parameters is determined in form of a coefficient of determination comprising curve.

3. Method according to claim 1, characterized in that the specific dependency of the parameters is determined by a setting range, which is depended on a given threshold value for the optical property of the film web.

4. Method according to claim 1, characterized in that the specific dependence is determined in the form of an envelope curve, which is depending on a given threshold value for the optical property of the film web.

5. Method according to claim 1, characterized in that a measured variable, which describes a geometric or functional property of film web and is dependant on an optical property, is determined by means of an optical sensor as a third parameter of the method, wherein the determined parameter is stored in a data base in ordered manner with reference to the detected parameters according to claim 1, and whereby from thein the data base storeddata systematically a specific dependency between the parameters is derived.

6. Method according to claim 1, characterized in that a measured variable is determined by means of a sensor as a further parameter of the method, in particular a process variable from the spatial environment of the manufacturing process or the production process of the film web, in particular none setting variable, wherein the specific parameter is stored in a data base in ordered manner referring to the parameters detected according to one of the preceding claims, and a specific dependence between the parameters is derived from the data stored in the data base systematically.

7. Method according to claim 1, characterized in that the specific dependency between the parameters is systematically derived and therefore data from an existing database are used.

8. Method according to claim 1, characterized in that the specific dependency between the parameters is systematically derived and for that an already existing database is continuously extended.

9. Method according to claim 1, characterized in that the specific dependence between the parameters is derived systematically and for that only data of a specific manufacturing device are used.

10. Method according to claim 1, characterized in that the specific dependence between the parameters is systematically derived, and for that data from a plurality of manufacturing devices are used for the production of film webs.

11. Method according to claim 1, characterized in that the specific dependence between the parameters is derived systematically, and for that data from a variety of manufacturing devices of different art are used for the production of film webs.

12. Method according to claim 1, characterized in that the specific dependence between the parameters is derived systematically, and for that data from a variety of manufacturing devices are used for the production of film webs of a producer and/or many producers.

13. Method according to claim 1, characterized in that the specific dependence between the parameters is systematically derived, and for that data from a plurality of manufacturing devices for producing film webs are synchronized with a data cloud.

14. Method according to claim 1, characterized in that the specific dependence between the parameters is determined heuristically.

15. Method according to claim 1, characterized in that the specific dependence between the parameters is determined mathematically.

16. Method according to claim 1, characterized in that the specific dependence between the parameters is determined by an optimization method.

17. Method according to claim 1, characterized in that the specific dependence between the parameters is determined by a self-learning optimization method.

18. Method according to claim 1, characterized in that a measured variable determines the optical properties of the film web, in particular the degree of gloss of the film and/or the haze of the film and/or the transparency of the film and/or the optical density of the film and/or the reflection grad of the film and/or the transmittance of the film and/or the printed image the film and/or the wrinkle image of the film and/or any scratches on the film and/or the surface topography of the film and/or the layer thicknesses of the film and/or the single layer thicknesses of the film and/or the tension within the film.

19. Method according to claim 1, characterized in that a measured variable determines functional properties of the film web in dependence of the optical properties, in particular the raw materials used and/or the proportions of the individual raw materials and/or the proportion of recycled material and/or the water vapour permeability of the film and/or the breathability of the film and/or the barrier properties of the film and/or the stretch rate of the film and/or the flatness position of the film and/or the thickness of the film and/or the profile of the film and/or the tackiness of the film and/or the uniformity of the result of stretching and/or the molecular orientation of the film.

20. Method for adjusting the quality of a with a blown film or cast film process manufactured film web, whereby the quality is measured and adjusted inline, characterized in that an optical property of the film web is determined by means of a sensor inline on the produced film web, and a setting variable set value is adjusted inline based on the determined optical property, wherein the adjusting the setting variable is performed by adjusting an actuator, wherein the setting variable set value is described for the specific the optical property by a systematic dependency, which is preferably determined by a method of claim 1, and by adjusting the setting variable the quality of the film web is changed such that a desired property is increased in its manifestation and/or an undesirable property is reduced in its manifestation.

21. Method according to claim 20, characterized in that the quality of the film web has a geometric property.

22. Method according to claim 20, characterized in that the quality of the film web has an optical property.

23. Method according to claim 20, characterized in that the quality of the film web has a functional property.

24. Method according to claim 20, characterized in that the quality of the film is adjusted inline and that it corresponds to the desired quality to the film web, so that it does not have measurable disturbances.

25. Method according to claim 20, characterized in that the desired quality of the film web is specified manually.

26. Method according to claim 20, characterized in that the desired quality of the film web is automatically specified.

27. Method according to claim 20, characterized in that more than one measured variable, which in particular detect optical properties of the film web, are measured inline on the produced film web as parameters of the method by means of one or more sensors.

28. Method according to claim 20, characterized in that the systematic dependency, which specifies the setting variable depending on the measured value, considers the process parameters of film production.

29. Method according to claim 20, characterized in that the measured value of the quality of the film web is determined with an optical measuring system.

30. Method according to claim 20, characterized in that the measured value of the quality of the film web is measured based on the optical properties of the film.

31. Method according to claim 20, characterized in that the quality of the film web is adjusted with the nozzle unit, in particular an annular nozzle in the blow head in a blown film plant or a wide slot nozzle in a cast film plant.

32. Method according to claim 20, characterized in that the quality of the film web is adjusted by the recipe of the plastic melt.

33. Method according to claim 20, characterized in that the quality of the film web is adjusted by the stretching of the film.

34. Method according to claim 20, characterized in that the quality of the film web is adjusted with an aftertreatment section.

35. Method according to claim 20, characterized in that a property measurement system determines optical properties of the film web, in particular the degree of gloss of the film and/or the haze of the film and/or the transparency of the film and/or the optical density of the film and/or the reflectance of the film and/or the transmittance of the film and/or the print image of the film and/or the wrinkle image of the film and/or any scratches on the film and/or specks and/or the surface topography of the film and/or the layer thicknesses of the film and/or the single layer thicknesses of the film and/or the layer shift of a film and/or the tension within the foil.

36. Method according to claim 20, characterized in that the property measuring system determines functional properties of the film web depending on the optical properties, in particular the used raw materials and/or the proportions of individual raw materials and/or the proportion of recyclate and/or the water vapour permeability of the film and/or the breathability of the film and/or the barrier properties of the film and/or stretch rate of the film and/or the flatness position of the film and/or the thickness of the film and/or the profile of the film and/or the tackiness of the film and/or the uniformity of the stretch result and/or the molecular orientation of the film.

37. Method according to claim 20, characterized in that the setting variable set value in the production process of the film web for affecting the quality of the film is determined via a suitable specific algorithm.

38. Method according to claim 20, characterized in that the setting variable set value in the production process of the film web for affecting the quality of the film is determined via a suitable specific algorithm, wherein the algorithm uses an inline control deviation, i.e. the difference between the desired quality of the film and the measured quality of the film as input value.

39. Method according to claim 20, characterized in that the quality of the film is adjusted by adjusting a setting variable set value by reducing an error image of a second errorin particular completelyin order to have ancompared with the error image of the second errormore increasing error image of a first error, to conclude to the dimension of the first error.

40. Method according to claim 39, characterized in that the quality of the film is adjusted by adjusting a setting variable set value, in that the error image of the first errorespecially completeis reduced.

41. Method for producing a film web, wherein a blown film or cast film plant is operated during the manufacturing process, wherein during the manufacturing process, a method is carried out according to claim 1.

42. Device for producing a film web, wherein the device comprises an extruder for plasticizing a thermoplastic, a nozzle for the escape of the plastic, a deflection part and a winder, characterized in that the device comprises an actuator for inline affecting the quality of the film and a data processing and evaluation unit, wherein the data processing and evaluation unit has a programming, wherein the programming is performed for carrying out a method according to claim 1.

43. Device according to claim 42, characterized in that the device comprises a property measuring system for inline detecting an optical property of the film web.

44. Device according to claim 42, characterized in that the device is a measured variable measuring system for determining a measured value of the production process, in particular a process variable.

45. Device according to claim 42, characterized in that the device comprises a measured variable measuring system for determining a setting variable of the production process.

46. Device according to claim 42, characterized in that the device comprises an actuator for inline affecting the quality of the film having segmented control zones.

47. Device according to claim 42, characterized in that the device for producing a film web, is performed in particular in the form of a blown film or a cast film.

Description

[0275] The invention will be described below with reference to an exemplary embodiment explained in detail on the drawing. It is shown:

[0276] FIG. 1 shows a schematic view of a blown film plant,

[0277] FIG. 2 shows a schematic representation of a data processing system and

[0278] FIG. 3 shows in schematic view an alternative blown film plant.

[0279] The blown film plant 1 in FIG. 1 consists essentially of an extruder 2, a blow head 3, a reversing turn-out 4, a treatment section 5 and a winder 6.

[0280] The extruder 2 conveys and plasticizes a plastic melt. To the plastic melt is added as an additive calcium carbonate in the extruder 2. The plastic melt passes through an annular gap nozzle (not numbered) in a blow head 3. The leaving plastic melt forms a film bubble 7, which is pulled in a flattening part 8 from a pair of take-off rollers 9, 10 to a folded, doubly flattened film web 13.

[0281] The doubly flattened film web 13 is further taken and leaded into the reversing turn-out 4 (German: Wendeabzug).

[0282] The reversing turn-out is driven by a motor 11 and performs a reversing movement 12, through which any deviations occurring in the film thickness profile of the doubly flattened film web 13 are laid.

[0283] Behind the reversing turn-out 4, the double flattened film web is fed into the treatment section 5, which stretches the double-laid flat film web 13 in this embodiment monoaxially inline in the machine direction.

[0284] Behind the treatment section 5, the doubly flattened film web 13 is fed to the winder 6 and is there wound up to a film wrap.

[0285] The calcium carbonate added as an additive to the starting material dims the film web.

[0286] Between the treatment section 5 and the winder 6 passes the double flattened film web 13 to a measuring system 14 for detecting an optical property 15 of the produced double-laid film web 13.

[0287] The optical property 15 of the doubly flattened film web 13 is here in particular the transmittance. Specifically, the transmission gives the double flattened film web 13 depending on the value, inhomogeneity and course in particular information on any deviations in the stretching, in the film thickness profile or the homogeneity of the melt.

[0288] The transmission of the doubly flattened film web 13 is determined with a through-transmitted light procedure. In this case, light is projected onto the doubly flattened film web 13, and the transmission is determined from the reflected part of the light.

[0289] Different types of light can be used. Conceivable types of light are in particular laser light and/or white light and/or LED light and/or infrared light. Conceivable, however, are any other types of light.

[0290] The optical property 15 of the doubly flattened film web 13 becomes common fed with a reversing angle 16 of the reversing turn-out 4 of a data processing and evaluation 17.

[0291] The data processing and evaluation unit 17 is adapted to carry out a method for indirect derivation of a systematic dependence of a film web between a setting variable of the manufacturing process, in particular a setting variable of the annular gap of the blow head 3, and an optical property 15 of the produced double flattened film web 13 and a method for adjusting the quality of the produced twice flattened film web 13, wherein the quality is measured inline and is adjusted by means of a setting variable of the annular nozzle of the blow head 3.

[0292] The quality influences are evaluated with a corresponding algorithm from the determined, the film quality descriptive optical property 15, wherein a systematic dependence of the involved parameters is used and is used for adaptation of the film quality of the double flattened film web 13.

[0293] A data processing system 20 for a plant for producing a film web consisting of a database 30, a measuring system 40 for determining an optical film characteristic of a film, a setting variable system 50 for monitoring, recording and adjusting a setting variable and a data detection and evaluation unit are shown schematically in FIG. 2.

[0294] The setting variable system 50 is connected to the annular slit nozzle of a blow film plant. The setting variables are the in adjustment sectors divided slot widths 51, 52 of the annular slit nozzle with the setting values 55, 56. The points represented in the data element of the setting variable system 50 make clear that there can be a large number of adjustment sectors. By way of example, two adjustment sectors are considered here.

[0295] The recorded data of the setting variable system 50 is sent forwarded to the database 30.

[0296] The measuring system 40 determines the optical properties 45, 46 of the film web in measuring sectors 41, 42. The points illustrated in the data element of the measurement system 40 illustrate that there can exist a plurality of measuring sectors. Exemplary here considered are two measuring sectors.

[0297] The recorded data of the measuring system 40 are forwarded to the database 30.

[0298] Database 30 allocates the data and assigns them to data points (55, 45), (55, 46), (56, 45), (56, 46), respectively. These data points are continuous saved.

[0299] The data detection and evaluation unit 60 can access the data elements of the database 30.

[0300] The data detection and evaluation unit 60 performs with the data elements of the database 30 an indirect method of deriving a systematic dependency of a film web between a setting variable with the corresponding setting values 55, 56 of the manufacturing process and the optical properties 45, 46 of the produced film web.

[0301] The resulting systematic dependency is also stored in the database 30 (not shown here).

[0302] Furthermore, the data detection and evaluation unit 60 performs a method of adjusting the quality of a film web. Thereby, the data detection and evaluation unit 60 uses the inline measured optical properties 45, 46 of the film web, compares it with quality specifications for the optical properties of the film web and carries out in the case of deviations from the required quality the method for adjusting the quality of the film web.

[0303] The method of adjusting the quality of the film web utilizes the systematic dependence of a film web between a setting variable and the corresponding setting values 55, 56 of the production method and the optical properties 45, 46 of the produced film web. In this case, the setting values 55, 56 are adapted corresponding to the systematic dependence in dependence of the optical properties 45, 46.

[0304] To make this adjustment, the data detection and evaluation unit 60 communicates with the setting variable system 50, which performs and monitors the adjusting of the setting values 55, 56.

[0305] The blown film plant 70 in FIG. 3 consists essentially of an extruder 71, a blow head 72, a flattening part 73, a treatment section 74, a reversing turn-out 75, optionally a slot device 76 or a seam station 77 (Germen: Besumstation), a first winder 78, a second winder 79, a first measuring system 86, a second measuring system 87 and a data detection and evaluation unit 88.

[0306] The extruder 71 conveys and plasticizes during operation of the blown film unit 70 a plastic melt, which is conveyed into the blow head 72.

[0307] The blow head 72 has an annular gap nozzle 80 divided into adjusting segments (not shown).

[0308] The plastic melt emerging from the blow head 72 forms a film bubble 81, which has an axis 82 and is folded in the flattening part 73 to a double flattened film web 83.

[0309] The doubly flattened film web 83 is withdrawn from a pair of take-off rollers 84, 85 and further passed into the treatment section 74.

[0310] The treatment section 74 stretches the double flattened film web 83. After the treatment path 74 the double flattened film web 83 runs in the machine direction into the reversing turn-out 75.

[0311] Behind the reversing turn-out 75 the double flattened film web 83 passes optionally a slot device 76 or a seam station 77.

[0312] The slot device 76 slits the double flattened film web 83 into or into the direct vicinity of the two folding edges, so that from the doubly flattened film web 83 two superimposed film webs 89, 90 are made.

[0313] The seam station 77, which is used as an alternative, cuts in the vicinity of the two folding of the double flattened film web 83, each, an edge strip of double flattened film web 83, so that from the doubly flattened film web 83 two superimposed film webs 89, 90 are made. When using a seam station 77 the edge strips (not shown) are removed with an edge strip removing part (not imaged).

[0314] Behind the optionally used slot device 76 or seam station 77 the superimposed film webs 89, 90 are separated from each other and then pass through a measuring system 86, 87 for detecting an optical property 91, 92 of the manufactured film webs 89, 90 and are fed finally, each, to one winder 78, 79 and wound there, each, to a film wrap.

[0315] As an alternative to the use of two measuring systems 86, 87 at low temporal rates of change of the optical property 93 of the double flattened film web 83 only a measuring system 86 can be used for detecting an optical property 91 of the produced film web 89, since this is due to the laying of the folds (not formed) representative by the reversing turn-out 75 by 180 relative to the circumferential angle (not shown) of the film bubble 81 of the double flattened film web 83 at low temporal change rates of the optical property 93 of the optical property 93 of the double-laid film web 83.

[0316] The optical properties 91, 92 of the film webs 89, 90 produced are here in particular the transmittance. Specifically, the transmission of the film web 89, 90 depending on the value, the inhomogeneity and the course gives, in particular, information about any deviations in the stretching, in the film thickness profile or the homogeneity of the melt.

[0317] The transmission of the film webs 89, 90 is determined by a transmitting-through light method. In this case, light is projected onto the film web 89, 90, and from the reflected part of the light the transmission is determined.

[0318] Different types of light can be used. Conceivable types of light are in particular laser light and/or white light and/or LED light and/or infrared light. Conceivable, however, are any other types of light.

[0319] The optical property 91, 92 of the film webs 89, 90 is given together with a reversing angle 94 of the reversing turn-out 75 and a treatment section angle 95 of the treatment section 74 of a data processing and evaluation unit 88.

[0320] The data processing and evaluation unit 88 is configured to perform a method for indirect derivation of a systematic dependence of a film web between a setting variable of the manufacturing method, in this case in particular a setting variable of the annular gap nozzle 80 of the blow head 72, and an optical property 91, 92 of the produced film web 89, 90 and a method for adjusting the quality of the produced film web 89, 90, wherein the quality is inline measured and adjusted by means of a control of a setting variable of the annular gap nozzle 80 of the blow head 72.

[0321] The quality influences are evaluated with a corresponding algorithm from the determined, the film quality descriptive optical property 91, 92, wherein a systematic dependence of the parameters involved is formed and is used for adaptation the film quality of the film web 89, 90.

LIST OF REFERENCE NUMBERS USED

[0322] 1 blown film plant

[0323] 2 extruder

[0324] 3 blow head

[0325] 4 reversing turn-out

[0326] 5 treatment section

[0327] 6 winder

[0328] 7 foil bubble

[0329] 8 flattening part

[0330] 9 take-out roll

[0331] 10 take-out roll

[0332] 11 motor

[0333] 12 reversing movement

[0334] 13 double laid film web

[0335] 14 measuring system

[0336] 15 optical property

[0337] 16 reversing angle

[0338] 17 data processing and evaluation unit

[0339] 20 data processing system

[0340] 30 data base

[0341] 40 measuring system

[0342] 41 measuring sector

[0343] 42 measuring sector

[0344] 45 optical property

[0345] 46 optical property

[0346] 50 setting variable system

[0347] 51 slot width

[0348] 52 slot width

[0349] 55 setting value

[0350] 56 setting value

[0351] 60 data detection and evaluation unit

[0352] 70 blown film plant

[0353] 71 extruder

[0354] 72 blow head

[0355] 73 flattening part

[0356] 74 treatment section

[0357] 75 reversing turn-out

[0358] 76 slot device

[0359] 77 seam station

[0360] 78 winder

[0361] 79 winder

[0362] 80 annular gap nozzle

[0363] 81 foil bubble

[0364] 82 axis

[0365] 83 double laid film web

[0366] 84 take-out roll

[0367] 85 take-out roll

[0368] 86 measuring system

[0369] 87 measuring system

[0370] 88 data detection and evaluation unit

[0371] 89 film web

[0372] 90 film web

[0373] 91 optical property

[0374] 92 optical property

[0375] 93 optical property

[0376] 94 reversing angle

[0377] 95 treatment section angle