METHOD FOR PRODUCING FUNCTIONAL WATER SOLUBLE FILMS

Abstract

Described herein is a process for producing a water-soluble foil, wherein the water-soluble foil includes at least one layer S1) including a polymer composition P1) obtainable by free-radical polymerization of a monomer composition M1) including at least one monomer A) selected from ,-ethylenically unsaturated mono- and dicarboxylic acids, salts of ,-ethylenically unsaturated mono- and dicarboxylic acids, anhydrides, of ,-ethylenically unsaturated mono- and dicarboxylic acids and mixtures thereof, in the presence of at least one polyether component PE) selected from polyetherols having a number-average molecular weight of at least 200 g/mol, mono- and di(C.sub.1-C.sub.6-alkyl) ethers of such polyetherols, surfactants containing polyether groups, and mixtures thereof, where the foil may also include further layers, and where the layers are cast onto a carrier material.

Claims

1. A process for producing a functional water-soluble foil, wherein the water-soluble foil comprises at least one layer S1) comprising a polymer composition P1) obtainable by free-radical polymerization of a monomer composition M1) in the presence of at least one polyether component PE), wherein M1) comprises at least one monomer A) selected from ,-ethylenically unsaturated mono- and dicarboxylic acids, salts of ,-ethylenically unsaturated mono- and dicarboxylic acids, anhydrides, of ,-ethylenically unsaturated mono- and dicarboxylic acids and mixtures thereof, in the presence of at least one polyether component PE) selected from polyetherols having a number-average molecular weight of at least 200 g/mol, mono- and di(C.sub.1-C.sub.6-alkyl) ethers of such polyetherols, surfactants containing polyether groups, and mixtures thereof, wherein the process comprises the following steps: (a) preparing an aqueous solution of the polymer composition P1), wherein the aqueous solution may comprise, as well as or in place of water, alcohol such as 2-propanol, (b) casting the aqueous polymer composition P1) from (a) as a film onto a carrier material, (c) optionally drying the film after an applying of S1) to the carrier material, (d) applying a layer S2), wherein layer S2) comprises at least one polymer P2) which is different than the polymer composition P1) and is selected from natural and modified polysaccharides, homo- and copolymers comprising repeat units which derive from vinyl alcohol, vinyl esters, alkoxylated vinyl alcohols or mixtures thereof, homo- and copolymers comprising at least one copolymerized monomer selected from N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, 2-vinylpyridine, 4-vinylpyridine, salts of the three latter monomers, vinylpyridine N-oxide, N-carboxymethyl-4-vinylpyridium halides and mixtures thereof, homo- and copolymers of acrylic acid and/or methacrylic acid and at least one copolymerized maleic monomer selected from maleic acid, maleic anhydride, maleic salts and mixtures thereof, copolymers comprising at least one copolymerized (meth)acrylic monomer selected from acrylic acid, methacrylic acid, salts thereof and mixtures thereof and at least one copolymerized hydrophobic monomer selected from C.sub.1-C.sub.8-alkyl esters of (meth)acrylic acid, C.sub.2-C.sub.10 olefins, styrene and -methylstyrene, copolymers comprising at least one copolymerized maleic monomer selected from maleic acid, maleic anhydride, maleic salts and mixtures thereof and at least one copolymerized C.sub.2-C.sub.8 olefin, homo- and copolymers of acrylamide and/or methacrylamide, polyamino acids, water-soluble or water-dispersible polyamides, polyalkylene glycols, mono- or diethers of polyalkylene glycols, polyalkylene oxides, for example polyethylene oxide, and mixtures thereof, (e) optionally drying the film after the applying of S2) to the carrier material, (f) optionally applying one or more further layers S1) and/or S2), (g) optionally drying the film after the applying of one or more further layers S1) and/or S2) to the carrier material in (f), (h) drying the foil after the applying of all layers S1) and S2) to the carrier material, wherein layers S1) and/or S2) may be applied in a freely chosen sequence or else simultaneously and in each case optionally dried after every application of one or more layers.

2. The process according to claim 1, wherein at least one of the layers comprises at least one additive.

3. The process according to claim 1, wherein, in step (a), the polymer composition P1) is dissolved in water so as to give a solution of at least about 55% by weight of polymer composition, measured by a total mass of polymer composition P1) and water.

4. The process according to claim 1, wherein the solution is cast onto a carrier material in step (b) by a predosed method.

5. The process according to claim 1, wherein the carrier material from step (b) consists of a material selected from the group consisting of iron alloy, nonwoven, polyvinyl alcohol, (oriented) polypropylene, polyethylene, polyethylene terephthalate, polyvinyl chloride, polystyrene, polytetrafluoroethylene, and polyalkylene glycol.

6. The process according to claim 1, wherein the polymer composition P1) is cast onto the carrier material in step (b) in a polymerized state as an aqueous solution.

7. The process according to claim 1, wherein layer S1) is dried down to a residual moisture content of 15% by weight or less, measured by a total mass of the applied layer S1).

8. The process according to claim 1, wherein the casting in step (b) onto the carrier material is effected at reduced pressure relative to an ambient pressure of a casting device.

9. The process according to claim 1, wherein the carrier material from step (b) has been coated with a composition comprising talc, surfactant, wax, polyolefin, polyethylene, polypropylene, polyvinyl chloride, polystyrene, or silicone.

10. The process according to claim 1, wherein two or more of layers S1) and optionally S2) are applied simultaneously to the carrier material in step (b).

11. The process according to claim 1, wherein an applying of multiple layers is conducted simultaneously by a multilayer predosed method or cascade casting.

12. The process according to claim 1, wherein the carrier material from step (b) is selected from the group consisting of nonwoven, polyvinyl, polyethylene terephthalate, polyvinyl chloride and polyalkylene glycol, and the carrier material, after drying of all applied layers S1) and optionally S2), remains bonded to the functional water-soluble foil.

13. The process according to claim 1, wherein a residual moisture content of the functional water-soluble foil is not more than 15% by weight, based on a total mass of the foil, and this residual moisture content is attained only after the applying of all layers S1) and S2).

14. The process according to claim 1, wherein the functional water-soluble foil comprises at least one layer S1), at least one layer S2), and a total of at least 3 layers.

15. The process according to claim 1, wherein layer S1), at a residual moisture content of not more than 15% by weight, has a thickness of 10 to 200 m.

16. A water-soluble foil producible according to claim 1.

17. The process according to claim 1, wherein at least one of the layers comprises at least one additive selected from the group consisting of plasticizers, scavengers, further polymers, gas permeability and water vapor permeability modifiers, antistats, lubricants, slip agents, dissolution auxiliaries, dyes, pigments, enzymes, corrosion inhibitors, defoamers, fragrances, thickeners, solubilizers, solvents, pH adjusters, antiredeposition agents, optical brighteners, graying inhibitors, dye transfer inhibitors, active antimicrobial ingredients, antioxidants, UV absorbers, antiyellowing agents, bitter substances and mixtures thereof.

18. The process according to claim 1, wherein the solution is cast onto a carrier material in step (b) by a slot die.

19. The process according to claim 16, wherein an applying of multiple layers is conducted simultaneously by a multislot die.

Description

[0339] The figures show:

[0340] FIG. 1 1. stirrer unit; 2. inlet/outlet; 3. jacketed tank; 4. pump; 5. pump circulation; 6. filtration units; 7. tank

[0341] FIG. 2 1. unwinding with roll of the carrier material; 2. support roll; 3. box applicator; 4. liquid feed (feed); 5. online measurement of basis weight. 6./7./8. convective drier (different T and air flow); 9. winding of the coated carrier material

[0342] FIG. 3 1. unwinding with roll of the carrier material; 2. support roll; 3. slot die for applying the polymer composition; 4. liquid feed to the slot die (feed); 5./6./7. convective drier (different T and air flow); 8. winding of the coated carrier material

[0343] FIG. 4 1. unwinding with roll of the carrier material; 2. support roll; 3. dilaminar slot die for simultaneous application of two polymer compositions; 4. liquid feed to the slot die (bottom layer); 5. liquid feed to the slot die (top layer); 6./7./8. convective drier (different T and air flow); 9. winding of the coated carrier material

[0344] FIG. 5 1. dilaminar slot die for simultaneous application of two polymer compositions; 2. liquid feed to the slot die (bottom layer); 3. liquid feed to the slot die (top layer); 4. steel belt as carrier material (run over both rolls in circulation); 5./6. convective drying zones (different T and air flow); 7. removal of the dilaminar foil from the steel belt; 8. separate foil; 9./10. further drying of the separate dilaminar foil (different T and air flow); 11. chill roll (optional); 12. winding of the dilaminar foil

[0345] FIG. 6 1. unwinding with roll of the carrier material; 2. support roll; 3. spray nozzle; 4. liquid feed (feed); 5./6. convective drier (different T and air flow); 7. unwinding of lamination foil; 8. support roll; 9. contact roll; 10. winding of the joined foil composite (laminate)

[0346] FIG. 7 1. dilaminar slot die for simultaneous application of two polymer compositions; 2. liquid feed to the slot die (bottom layer); 3. liquid feed to the slot die (top layer); 4. heating cylinder; 5. removal of the dilaminar foil from the steel belt; 6. separate foil; 7./8. further drying of the separate dilaminar foil (different T and air flow); 9. chill roll (optional); 10. winding of the dilaminar foil

[0347] FIG. 8 1. dilaminar slot die for simultaneous application of two polymer compositions; 2. liquid feed to the slot die (bottom layer); 3. liquid feed to the slot die (top layer); 4. steel belt as carrier material (run over both rolls in circulation); 5./6. convective drying zones (different T and air flow); 7. removal of the dilaminar foil from the steel belt; 8. separate foil; 9./12. further drying of the separate dilaminar foil (different T and air flow); 10. slot die for application of a further lamina of polymer composition; 11. liquid feed to the slot die; 13. chill roll (optional); 14. winding of the dilaminar foil

[0348] FIG. 9 1. dilaminar slot die for simultaneous application of two polymer compositions; 2. liquid feed to the slot die (bottom layer); 3. liquid feed to the slot die (top layer); 4. steel belt as carrier material (run over both rolls in circulation); 5./6. convective drying zones (different T and air flow); 7. removal of the dilaminar foil from the steel belt; 8. separate foil; 9./13. further drying of the separate dilaminar foil (different T and air flow); 10. application roll for application of a further lamina of polymer composition; 11. chamber for polymer composition; 12. liquid feed (feed); 14. chill roll (optional); 15. winding of the dilaminar foil

[0349] FIG. 10 1. carrier material; 2. support roll; 3. slot die for applying the polymer composition (mono- or multilaminar); 4. liquid feed to the slot die (feed); 5. vacuum box; 6. reduced pressure-generating fan; 7. coated carrier material

[0350] FIG. 11 1. film/substrate; 2. application rolls; 3. chamber applicator; 4. coating solution duct/feed; 5. return flow to the reservoir vessel

[0351] FIG. 12 1. film/substrate; 2. application rolls; 3. slot dies; 4. coating solution duct/feed

[0352] FIG. 13 1. doctor blade; 2. film/substrate; 3. guide roll/contact roll; 4. application roll; 5. coating solution reservoir

[0353] FIG. 14 1. coating solution reservoir; 2. roll; 3. doctor blade; 4. application roll; 5. film/substrate; 6. support roll/contact roll; 7. roll

[0354] The present invention is elucidated and illustrated in detail by the examples which follow without being restricted to the embodiments and features detailed therein.

EXAMPLES

[0355] Making Up the Solutions

[0356] Preparation of Polymer Composition P1-1)

TABLE-US-00001 TABLE 1 Feedstock Amount (% by wt.) Content (%) Initial charge C.sub.13C.sub.15 oxo alcohol 24.40 100.00 with 7 EO Water.sup.a) 18.40 100.00 Feed 1 Acrylic acid 48.80 100.00 Feed 2 Initiator.sup.b) 0.34 100.00 Water.sup.a) 3.89 100.00 Feed 3 2-Mercaptoethanol 0.49 100.00 Sodium hypophosphite 1.33 55.00 Water.sup.a) 2.42 100.00 .sup.a)demineralized water, .sup.b)2,2-azobis(2-methylpropionamidine) dihydrochloride (CAS No. 2997-92-4)

[0357] The initial charge was heated to 75 C. while stirring at 100 rpm. Then feeds 1, 2 and 3 were metered in within 4 h and the reaction mixture was polymerized for a further hour. The mixture was then allowed to cool down to room temperature. The polymer composition is obtained in the form of a transparent and viscous solution. The weight-average molecular weight M.sub.w of the polymer composition P1-6) obtained was 12 100 g/mol.

[0358] The weight-average molecular weight Mw of the polymer composition P1-1) obtained was determined by means of gel permeation chromatography (GPC) in aqueous solution using neutralized polyacrylic acid as polymer standard. In this type of molecular weight determination, the components of the polymer composition which comprise the aforementioned monomers M) in copolymerized form are ascertained.

Standard: neutralized polyacrylic acid. The calibration was carried out with narrow distribution Na-PAA standards from PSS (Polymer Standards Service GmbH) with molecular weights of M=1250 to M=1 100 000 g/mol. In addition, PAA standards from the American Polymer Standards Corporation with molecular weight M=1770 and M=900 g/mol were used. The values outside of this elution range were extrapolated.
Eluent: 0.01 mol/L phosphate buffer pH=7.4 in distilled water with 0.01 M NaN.sub.3
Flow rate: 0.8 mL/min
Injection volume: 100 L
Concentration: 1.5 mg/mL
The sample solutions were filtered through Millipore IC Millex-LG filter (0.2 m).
Column name: TSKgel GMPWXL
Column attachment: 2 separation columns (length=each 30 cm), exclusion limit 1000-8 000 000 g/mol
Detector: DRI Agilent 1200 UV Agilent 1200 VWD [260 nm]

[0359] Production of an Application Solution A (for Foil Layers of Polyvinyl Alcohol)

[0360] 18 g of a solid polyvinyl alcohol (Poval 26-88 from Kuraray, nonvolatile components: 97.5%) were dissolved in 82 g of deionized water at 60 C. while stirring. 1.8 g of glycerol (>99.5%, Sigma Aldrich) and 0.18 g of a C.sub.13C.sub.15 oxo alcohol with 7 EO were added to 100 g of the polyvinyl alcohol solution thus prepared. The solution was heated to 80 C. Polyvinyl alcohol application solution A was mixed well and heated at 80 C. until the air stirred in had escaped completely.

[0361] Production of an application solution B (for foil layers of polymer composition P1-1) To 397.30 g of the above-described polymer composition P1-1) are added, while stirring at 80 C., firstly 29.00 g of glycerol (>99.5%, Sigma Aldrich) and lastly 26.80 g of deionized water. Application solution B was mixed well and heated at 80 C. until the air stirred in had escaped completely.

[0362] Production of an application solution C (for foil layers of carboxymethyl cellulose) 4 g of a sodium carboxymethyl cellulose (WALOCEL CRT 2000 PA from Dow Wolff Cellulosics, solids content: 92%) were dissolved in 96 g of deionized water at 60 C. while stirring. 1 g of glycerol (>99.5%, Sigma Aldrich) was added to 100 g of the carboxymethyl cellulose solution thus prepared. The solution was heated to 80 C. The carboxymethyl cellulose application solution C was mixed well and heated at 80 C. until the air stirred in had escaped completely.

[0363] Production of an application solution D (for foil layers comprising a copolymer that acts as dye transfer inhibitor (DTI))

[0364] 51.55 g of a copolymer of 1-vinylpyrrolidone and 1-vinylimidazole (Sokalan HP 56 granules from BASF SE, solids content: 97%) were dissolved in 48.45 g of deionized water while stirring. 12.5 g of glycerol (>99.5%, Sigma Aldrich) were added to 100 g of the dye transfer inhibitor solution prepared. Subsequently, by addition of deionized water, the polymer concentration of the solution was adjusted to 35.0% by weight. Polymer application solution D was mixed well and heated at 80 C. until the air stirred in had escaped completely.

[0365] Aqueous solutions of layers S1-S2, if they are includable layers, are produced in stirred, heatable tanks (FIG. 1). These tanks consist of or are coated with corrosion-resistant materials. These include enameled tanks or those made of steels as described here above in general terms. The stirrers to be used should be designed such that they assure good mixing of the solution (e.g. Intermig, anchor stirrers, etc.), with minimization of the introduction of air into the solution, for example by complete immersion of the stirrer units into the solution or adjusted stirrer speed. To prepare the solution, water (generally deionized water) is initially charged and the appropriate polymer is added at room temperature while stirring. The mixture is then heated; this can be effected by adding direct steam or via jacket heating. When direct steam is used, the amount of water introduced by the steam is included in the overall mass balance. In addition, the polymers can also be mixed and/or dissolved with the water directly via speed-controlled mixers (dynamic mixers). The polymer solutions can be adjusted to processing temperature or regulated to this temperature later on in the process. Further admixtures such as plasticizers, fillers, active substances (enzymes, fragrances, etc.) can be initially charged together with the dilution water, or be added after the preparation of the solution or in the course of conveying of the solution. Feeds to further mixes and nozzles are designed either such that the temperature of the solution remains constant or such that it drops to a desired temperature. Some of these conduits have been designed such that the solution can be partly or entirely circulated, which means that it is possible to control the temperature of solutions and conduits in startup processes or in the event of interruptions or reduced throughput, and to prevent gel formation etc. In addition, there is at least one filter unit in said conduit zone, in which extraneous matter present and gel particles are removed. The filter unit is optionally back-flushable. The polymer solutions conveyed are optionally pumped prior to casting in a reservoir vessel, the inlet and outlet of which are in the base of the vessel. The inlet may optionally also be mounted at the side or the top of the vessel. There may optionally be a further stirrer unit in said reservoir vessel. The vessel should be configured such that the introduction of air into the solution is minimized. The incorporation of a reservoir vessel allows buffering of discontinuous solution production, and continuous casting of the film is assured. There is optionally a further filtration unit downstream of the reservoir vessel. Vessels and filters should be designed so as to minimize any temperature drop in the solution.

[0366] Foil Production

[0367] All layers formed from application solutions A to D here may additionally also comprise, inter alia, plasticizers as described here in general terms.

[0368] The foil layer composition corresponds to the composition of the multilayer foil after drying. The solutions applied are described in the general section Making up the solution.

[0369] Thickness measurement and determination of basis weight:

[0370] Film thicknesses were determined by means of a digital gauge (Mitutoyo Absolute Digimatic gauge, ID-H model) with a flat, circular stylus of diameter 5 mm. The thickness was measured over an average of at least 10 measurement positions per foil. The layer thickness variations are within a range of 10%. Basis weight was determined gravimetrically over an area of 80 mm80 mm.

Example 1.1

[0371] Dilaminar Foil A-B: 1st Layer of Polyvinyl Alcohol, 2nd Layer of Polymer Composition P1-1)

[0372] For production of the multilayer foil, in a coating system from Mathis AG with a box applicator as applicator (FIG. 2). Application solution A (production as described above) is initially charged in the box applicator and applied at a belt speed of 0.5 m/min to a siliconized polyester foil (foil thickness 36 m, Hostaphan RN 2PRK) as carrier material. By means of contactless online layer thickness measurement based on ultrasound absorption (MeSys GmbH, USM-200), the doctor blade gap is varied until attainment of the desired basis weight of 10 g/m.sup.2. Subsequently, the film is subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones, each of length 1 m, are 100, 80 and 60 C. in sequence in coating direction. The wound roll is removed from the winder and mounted in the unwinder in order to coat the second lamina thereon. In this subsequent step, application solution B is initially charged in the box applicator and applied to the carrier material already coated with A at a belt speed of 1 m/min. By means of contactless online layer thickness measurement based on ultrasound absorption (MeSys GmbH, USM-200), the doctor blade gap is varied until attainment of the desired basis weight of 70 g/m.sup.2. Subsequently, the film is subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones, each of length 1 m, are 100, 80 and 60 C. in sequence in coating direction. The carrier material can remain part of the roll for storage or transport and serves as separator. Prior to further use of the dilaminar A-B coating as a separate water-soluble foil, the dilaminar foil has to be removed. This can be effected in a separate step (rewinding from the roll to a new bobbin) or in the processing step itself, for example in pouch production. The foil produced in this way has a basis weight of about 80 g/m.sup.2 and comprises about 70 g/m.sup.2 of B.

Example 1.2

[0373] Dilaminar Foil A-B: 1st Layer of Polyvinyl Alcohol, 2nd Layer of Polymer Composition P1-1)

[0374] For production of the multilayer foil, a slot die from TSE Troller AG with width 150 mm is used in a coating system from Mathis AG (FIG. 3). The syringe initially charged with the free-flowing polymer composition, the liquid feed and the nozzle are at a controlled temperature of 40 C. Application solution A is applied by means of a syringe pump (Nexus 6000 from Chemyx) at 4.2 mL/min at a belt speed of 0.5 m/min to a siliconized polyester foil (foil thickness 36 m, Hostaphan RN 2PRK) as carrier material, and then subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones, each of length 1 m, are 100, 80 and 60 C. in sequence in coating direction. The wound roll is removed from the winder and mounted in the unwinder in order to coat the second lamina thereon. In this subsequent step, application solution B is applied by means of a syringe pump (Nexus 6000 from Chemyx) at 16.2 mL/min at a belt speed of 1 m/min to the carrier material already coated with A, and then subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones are 100, 80 and 60 C. in sequence in coating direction. The carrier material can remain part of the roll for storage or transport and serves as separator. Prior to further use of the dilaminar A-B coating as a separate water-soluble foil, the dilaminar foil has to be removed. This can be effected in a separate step (rewinding from the roll to a new bobbin) or in the processing step itself, for example in pouch production. The foil produced in this way has a basis weight of about 80 g/m.sup.2 and comprises about 70 g/m.sup.2 of B.

Example 1.3

[0375] Dilaminar Foil A-B: 1st Layer of Polyvinyl Alcohol, 2nd Layer of Polymer Composition P1-1)

[0376] For production of the multilayer foil, a dilaminar slot die from TSE Troller AG with width 150 mm is used in a coating system from Mathis AG (FIG. 4). The two syringes initially charged with the free-flowing polymer compositions, the liquid feed and the nozzle are at a controlled temperature of 40 C. Application solution A is fed into the front slot in coating direction via a syringe pump (Nexus 6000 from Chemyx) at 4.2 mL/min. Application solution B is fed into the rear slot in coating direction via a syringe pump (Nexus 6000 from Chemyx) at 8.1 mL/min at a belt speed of 0.5 m/min. Thus, by parallel operation of the two pumps, both polymer compositions are applied simultaneously to the carrier material and then subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones are 120, 110 and 60 C. in sequence in coating direction. The carrier material can remain part of the roll for storage or transport and serves as separator. Prior to further use of the dilaminar A-B coating as a separate water-soluble foil, the carrier foil has to be removed. This can be effected in a separate step (rewinding from the roll to a new bobbin) or in the processing step itself, for example in pouch production. The foil produced in this way has a basis weight of about 80 g/m.sup.2 and comprises about 70 g/m.sup.2 of B.

Example 1.4

[0377] Dilaminar Foil A-B: 1st Layer of Polyvinyl Alcohol, 2nd Layer of Polymer Composition P1-1)

[0378] For production of the multilayer foil, a dilaminar slot die from TSE Troller AG with width 150 mm is used in a foil casting system with a continuous steel belt (CrNi steel, length 16 m) (FIG. 5). The two reservoir vessels initially charged with the free-flowing polymer compositions, the liquid feed and the nozzle are at a controlled temperature of 40 C. Application solution A is fed into the front slot in coating direction via a gear pump (P64627/71023201/1MA-A/6-19 from Gather) at 16.7 mL/min. Application solution B is fed into the rear slot in coating direction via a gear pump (P64627/71023201/1MA-A/6-19 from Gather) at 27.7 mL/min at a belt speed of 1 m/min. Thus, by parallel operation of the two pumps, both polymer compositions are applied simultaneously to the carrier material, in this case a CrNi steel belt, and then subjected to convective drying in a slot die drier. The temperatures, 150 C. in the upper part and 60 C. in the lower part, and the fan output in the drier zones are chosen such that the moisture content of water is <15% by weight when the foil is removed from the steel belt. After the separation of steel belt and foil, the foil is subsequently subjected in separate form to further drying in a convective drier at 60 C. Prior to the winding, the foil is cooled to room temperature by means of a chill roll and the surface is treated with talc as separating agent. The foil produced in this way has a basis weight of about 140 g/m.sup.2 and comprises about 120 g/m.sup.2 of B.

Example 2.1

[0379] Trilaminar Foil A-B-A: 1st Layer of Polyvinyl Alcohol, 2nd Layer of Polymer Composition P1-1), 3rd Layer of Polyvinyl Alcohol

[0380] For production of a trilaminar multilayer foil, in a coating system from Mathis AG with a box applicator as applicator (FIG. 2). Analogously to example 1.2, a dilaminar A-B coating is produced on the carrier foil beforehand. Application solution A is then initially charged in the box applicator and applied to the already twice-coated carrier material at a belt speed of 1 m/min. By means of contactless online layer thickness measurement based on ultrasound absorption (MeSys GmbH, USM-200), the doctor blade gap is varied until attainment of the desired basis weight of 10 g/m.sup.2. Subsequently, the trilaminar coating is subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones, each of length 1 m, are 100, 80 and 60 C. in sequence in coating direction. The carrier material can remain part of the roll for storage or transport and serves as separator. Prior to further use of the trilaminar A-B-A coating as a separate water-soluble foil, the carrier foil has to be removed. This can be effected in a separate step (rewinding from the roll to a new bobbin) or in the processing step itself, for example in pouch production. The foil produced in this way has a basis weight of about 90 g/m.sup.2 and comprises an average of about 70 g/m.sup.2 of B.

Example 2.2

[0381] Trilaminar Foil A-B-A: 1st Layer of Polyvinyl Alcohol, 2nd Layer of Polymer Composition P1-1), 3rd Layer of Polyvinyl Alcohol

[0382] For production of the trilaminar multilayer foil, a slot die from TSE Troller AG with width 150 mm is used in a coating system from Mathis AG (FIG. 3). Analogously to example 1.2, a dilaminar A-B coating is produced on the carrier foil. Subsequently, application solution A is applied again by means of a syringe pump (Nexus 6000 from Chemyx) at 8.3 mL/min at a belt speed of 1 m/min to the already twice-coated carrier material, and then subjected to convective drying in a slot die drier. Here too, the syringe initially charged with the free-flowing polymer composition, the liquid feed and the nozzle are at a controlled temperature of 40 C. The temperatures of the 3 drier zones, each of length 1 m, are 100, 80 and 60 C. in sequence in coating direction. The carrier material can remain part of the roll for storage or transport and serves as separator. Prior to further use of the trilaminar A-B-A coating as a separate water-soluble foil, the carrier foil has to be removed. This can be effected in a separate step (rewinding from the roll to a new bobbin) or in the processing step itself, for example in pouch production. The foil produced in this way has a basis weight of about 90 g/m.sup.2 and comprises an average of about 70 g/m.sup.2 of B.

Example 2.3

[0383] Trilaminar Foil A-B-A: 1st Layer of Polyvinyl Alcohol, 2nd Layer of Polymer Composition P1-1), 3rd Layer of Polyvinyl Alcohol

[0384] For production of the trilaminar multilayer foil, analogously to example 1.2, a dilaminar A-B coating is produced on the carrier foil. Subsequently, a PVOH foil (polyvinyl alcohol foil, Monosol M8630 from Kuraray, 76 m) is laminated (by means of thermal joining) or coated (by means of an adhesive) onto the dilaminar-coated carrier foil in a coating system from Kroenert (FIG. 6). For this purpose, at a belt speed of 5 m/min, the polymer composition surface is moistened with water by an ultrasound nozzle (WideTrack from SonoTek Corporation, nozzle frequency 48 kHz) at a pump rate of 18.0 mL/min (Nexus 6000 from Chemyx). In the coating module, under a pressure of 4 bar, the A foil and the moistened multilaminar-coated carrier foil are joined by a rubberized roll (Shore hardness 80). The carrier material can remain part of the roll for storage or transport and serves as separator. Prior to further use of the trilaminar A-B-A composite as a separate water-soluble foil, the carrier foil has to be removed. This can be effected in a separate step (rewinding from the roll to a new bobbin) or in the processing step itself, for example in pouch production. The foil produced in this way has a basis weight of about 156 g/m.sup.2 and comprises an average of about 70 g/m.sup.2 of B.

[0385] Tetralaminar Foil

Example 3.1

[0386] Tetralaminar Foil C-B-D-A: 1st Layer of Carboxymethyl Cellulose, 2nd Layer of Polymer Composition P1-1), 3rd Layer of Dye Transfer Inhibitor, 4th Layer of Polyvinyl Alcohol

[0387] For production of the multilayer foil, in a coating system from Mathis AG with a box applicator as applicator (FIG. 2). Application solution C is initially charged in the box applicator and applied at a belt speed of 0.5 m/min to a siliconized polyester foil (foil thickness 36 m, Hostaphan RN 2PRK) as carrier material. By means of contactless online layer thickness measurement based on ultrasound absorption (MeSys GmbH, USM-200), the doctor blade gap is varied until attainment of the desired basis weight of 10 g/m.sup.2. Subsequently, the film is subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones, each of length 1 m, are 100, 80 and 60 C. in sequence in coating direction.

[0388] The wound roll is removed from the winder and mounted in the unwinder in order to coat the second lamina thereon. In this subsequent step, application solution B is initially charged in the box applicator and applied to the carrier material already coated with A at a belt speed of 1 m/min. By means of contactless online layer thickness measurement based on ultrasound absorption (MeSys GmbH, USM-200), the doctor blade gap is varied until attainment of the desired basis weight of 70 g/m.sup.2. Subsequently, the film is subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones, each of length 1 m, are 100, 80 and 60 C. in sequence in coating direction.

[0389] The wound roll is removed from the winder and mounted in the unwinder in order to coat the third lamina thereon. In this subsequent step, application solution D is initially charged in the box applicator and applied to the carrier material already coated with C and B at a belt speed of 0.5 m/min. By means of contactless online layer thickness measurement based on ultrasound absorption (MeSys GmbH, USM-200), the doctor blade gap is varied until attainment of the desired basis weight of 40 g/m.sup.2. Subsequently, the film is subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones, each of length 1 m, are 100, 80 and 60 C. in sequence in coating direction.

[0390] The wound roll is removed from the winder and mounted in the unwinder in order to coat the fourth lamina thereon. In this subsequent step, application solution A is initially charged in the box applicator and applied to the carrier material already coated with C, B and D at a belt speed of 0.5 m/min. By means of contactless online layer thickness measurement based on ultrasound absorption (MeSys GmbH, USM-200), the doctor blade gap is varied until attainment of the desired basis weight of 10 g/m.sup.2. Subsequently, the film is subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones, each of length 1 m, are 100, 80 and 60 C. in sequence in coating direction.

[0391] The carrier material can remain part of the roll for storage or transport and serves as separator. Prior to further use of the tetralaminar C-B-D-A composite as a separate water-soluble foil, the carrier foil has to be removed. This can be effected in a separate step (rewinding from the roll to a new bobbin) or in the processing step itself, for example in pouch production. The foil produced in this way has a basis weight of about 130 g/m.sup.2 and comprises about 10 g/m.sup.2 of C, about 70 g/m.sup.2 of B and about 40 g/m.sup.2 of D.

Example 3.2

[0392] Tetralaminar Foil C-B-D-A: 1st Layer of Carboxymethyl Cellulose, 2nd Layer of Polymer Composition P1-1), 3rd Layer of Dye Transfer Inhibitor, 4th Layer of Polyvinyl Alcohol

[0393] For production of the multilayer foil, a slot die from TSE Troller AG with width 150 mm is used in a coating system from Mathis AG (FIG. 3). The syringe initially charged with the free-flowing polymer composition, the liquid feed and the nozzle are at a controlled temperature of 40 C. Application solution C is applied by means of a syringe pump (Nexus 6000 from Chemyx) at 18.8 mL/min at a belt speed of 0.5 m/min to a siliconized polyester foil (foil thickness 36 m, Hostaphan RN 2PRK) as carrier material, and then subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones, each of length 1 m, are 100, 80 and 60 C. in sequence in coating direction.

[0394] The wound roll is removed from the winder and mounted in the unwinder in order to coat the second lamina thereon. In this subsequent step, application solution B is applied by means of a syringe pump (Nexus 6000 from Chemyx) at 16.2 mL/min at a belt speed of 1 m/min to the carrier material already coated with C, and then subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones are 100, 80 and 60 C. in sequence in coating direction.

[0395] The wound roll is removed from the winder and mounted in the unwinder in order to coat the third lamina thereon. In this subsequent step, application solution D is applied by means of a syringe pump (Nexus 6000 from Chemyx) at 7.5 mL/min at a belt speed of 0.5 m/min to the carrier material already coated with C and B, and then subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones are 100, 80 and 60 C. in sequence in coating direction.

[0396] The wound roll is removed from the winder and mounted in the unwinder in order to coat the fourth lamina thereon. In this subsequent step, application solution A is applied by means of a syringe pump (Nexus 6000 from Chemyx) at 4.2 mL/min at a belt speed of 0.5 m/min to the carrier material already coated with C, B and D, and then subjected to convective drying in a slot die drier. The temperatures of the 3 drier zones are 150, 110 and 60 C. in sequence in coating direction.

[0397] The carrier material can remain part of the roll for storage or transport and serves as separator. Prior to further use of the tetralaminar C-B-D-A coating as a separate water-soluble foil, the carrier foil has to be removed. This can be effected in a separate step (rewinding from the roll to a new bobbin) or in the processing step itself, for example in pouch production. The foil produced in this way has a basis weight of about 130 g/m.sup.2 and comprises about 10 g/m.sup.2 of C, about 70 g/m.sup.2 of B and about 40 g/m.sup.2 of D.

Example 3.3

[0398] Tetralaminar Foil A-B-D-A: 1st Layer of Polyvinyl Alcohol, 2nd Layer of Polymer Composition P1-1), 3rd Layer of Dye Transfer Inhibitor, 4th Layer of Polyvinyl Alcohol

[0399] For production of the multilayer foil, a dilaminar slot die from TSE Troller AG with width 150 mm is used in a foil casting system with a continuous steel belt (CrNi steel, length 16 m) (FIG. 5). The two syringes initially charged with the free-flowing polymer compositions, the liquid feed and the nozzle are at a controlled temperature of 40 C. Application solution A is fed into the front slot in coating direction via a gear pump (P64627/71023201/1MA-A/6-19 from Gather) at 32.2 mL/min. Application solution B is fed into the rear slot in coating direction via a gear pump (P64627/71023201/1MA-A/6-19 from Gather) at 16.7 mL/min at a belt speed of 2 m/min. Thus, by parallel operation of the two pumps, both polymer compositions are applied simultaneously to the carrier material, in this case a CrNi steel belt, and then subjected to convective drying in a slot die drier. The temperatures, 150 C. in the upper part and 60 C. in the lower part, and the fan output in the drier zones are chosen such that the moisture content of water is <15% by weight when the foil is removed from the steel belt. After the separation of steel belt and foil, the foil is subsequently subjected in separate form to further drying in a convective drier at 60 C. Prior to winding, the foil is cooled to room temperature by means of a chill roll.

[0400] In a further step, a dilaminar slot die from TSE Troller AG with width 150 mm is used in a foil casting system with a continuous steel belt (CrNi steel, length 16 m) (FIG. 5). The two syringes initially charged with the free-flowing polymer compositions, the liquid feed and the nozzle are at a controlled temperature of 40 C. Application solution A is fed into the front slot in coating direction via a gear pump (P64627/71023201/1MA-A/6-19 from Gather) at 12.5 mL/min. Application solution D is fed into the rear slot in coating direction via a gear pump (P64627/71023201/1MA-A/6-19 from Gather) at 22.5 mL/min at a belt speed of 1.5 m/min. Thus, by parallel operation of the two pumps, both polymer compositions are applied simultaneously to the carrier material, in this case a CrNi steel belt, and then subjected to convective drying in a slot die drier. The temperatures, 150 C. in the upper part and 60 C. in the lower part, and the fan output in the drier zones are chosen such that the moisture content of water is <15% by weight when the foil is removed from the steel belt. After the separation of steel belt and foil, the foil is subsequently subjected in separate form to further drying in a convective drier at 60 C. Prior to winding, the foil is cooled to room temperature by means of a chill roll.

[0401] Subsequently, the D-A foil produced in the second step is laminated or coated onto the dilaminar A-B foil produced in the first step in a coating system from Kroenert (FIG. 6). For this purpose, at a belt speed of 5 m/min, the B surface is moistened with water by an ultrasound nozzle (WideTrack from SonoTek Corporation, nozzle frequency 48 kHz) at a pump rate of 18.0 mL/min (P64627/71023201/1MA-A/6-19 gear pump from Gather). In the coating module, under a pressure of 4 bar, the two foils are joined by a rubberized roll (Shore hardness 80) by joining the B and D layers. The foil produced in this way has a basis weight of about 130 g/m.sup.2 and comprises an average of about 70 g/m.sup.2 of B and about 40 g/m.sup.2 of D.

Example 3.4

[0402] Tetralaminar Foil A-B-C-A: 1st Layer of Polyvinyl Alcohol, 2nd Layer of Polymer Composition P1-1), 3rd Layer of Carboxymethyl Cellulose, 4th Layer of Polyvinyl Alcohol

[0403] For production of the multilayer foil, a dilaminar slot die from TSE Troller AG with width 150 mm is used in a foil casting system with a continuous steel belt (CrNi steel, length 16 m) (FIG. 5). The two reservoir vessels initially charged with the free-flowing polymer compositions, the liquid feed and the nozzle are at a controlled temperature of 40 C. Application solution A is fed into the front slot in coating direction via a gear pump (P64627/71023201/1MA-A/6-19 from Gather) at 32.2 mL/min. Application solution B is fed into the rear slot in coating direction via a gear pump (P64627/71023201/1MA-A/6-19 from Gather) at 16.7 mL/min at a belt speed of 2 m/min. Thus, by parallel operation of the two pumps, both polymer compositions are applied simultaneously to the carrier material, in this case a CrNi steel belt, and then subjected to convective drying in a slot die drier. The temperatures, 150 C. in the upper part and 60 C. in the lower part, and the fan output in the drier zones are chosen such that the moisture content of water is <15% by weight when the foil is removed from the steel belt. After the separation of steel belt and foil, the foil is subsequently subjected in separate form to further drying in a convective drier at 60 C. Prior to winding, the foil is cooled to room temperature by means of a chill roll.

[0404] In a further step, a dilaminar slot die from TSE Troller AG with width 150 mm is used in a foil casting system with a continuous steel belt (CrNi steel, length 16 m) (FIG. 5). The two reservoir vessels initially charged with the free-flowing polymer compositions, the liquid feed and the nozzle are at a controlled temperature of 40 C. Application solution A is fed into the front slot in coating direction via a gear pump (P64627/71023201/1MA-A/6-19 from Gather) at 16.7 mL/min. Application solution C is fed into the rear slot in coating direction via a gear pump (P64627/71023201/1MA-A/6-19 from Gather) at 37.5 mL/min at a belt speed of 1 m/min. Thus, by parallel operation of the two pumps, both polymer compositions are applied simultaneously to the carrier material, in this case a CrNi steel belt, and then subjected to convective drying in a slot die drier. The temperatures, 150 C. in the upper part and 60 C. in the lower part, and the fan output in the drier zones are chosen such that the moisture content of water is <15% by weight when the foil is removed from the steel belt. After the separation of steel belt and foil, the foil is subsequently subjected in separate form to further drying in a convective drier at 60 C. Prior to winding, the foil is cooled to room temperature by means of a chill roll.

[0405] Subsequently, the C-A foil produced in the second step is laminated (by means of thermal joining) or coated (by means of an adhesive) onto the dilaminar A-B foil produced in the first step in a coating system from Kroenert (FIG. 6). For this purpose, at a belt speed of 5 m/min, the polymer composition surface is moistened with water by an ultrasound nozzle (WideTrack from SonoTek Corporation, nozzle frequency 48 kHz) at a pump rate of 18.0 mL/min (P64627/71023201/1MA-A/6-19 gear pump from Gather). In the coating module, under a pressure of 4 bar, the two foils are joined by a rubberized roll (Shore hardness 80) by joining the B and C layers. The foil produced in this way has a basis weight of about 110 g/m.sup.2 and comprises an average of about 70 g/m.sup.2 of B and about 10 g/m.sup.2 of C.

[0406] Film Aftertreatment

[0407] Films consisting of S1) and optionally S2), on completion of drying or partial drying, can be subjected to further process steps. The stretching of the film (orienting) can be effected during the drying or thereafter; during the operation, the water content and the temperature of the film are monitored and controlled according to the degree of deformation. The orientation of the film is at least uniaxial, and this can be produced by standard methods such as roles or tenter frames, for example on commercially available systems such as Andritz Biax (described in DE 3939721 A1), for example. By means of altered role geometries, it is also possible to produce nonuniformly stretched films. Stretched films show higher mechanical tensile strength compared to their unstretched comparative films. Without being bound to the theory, this arises as a result of alignment of the polymer chains and enhanced interaction thereof.

[0408] On completion of drying or partial drying, prior to the winding, the surface can be treated with talc or other substances as separating agents.

[0409] In addition, films consisting of S1) to optionally of S2), after drying, orientation etc., can be printed; the films here are rolled by means of rolls along a color-bearing and embossed roller; this transfers the color to the film in the desired pattern. This process can be effected on both sides if desired. It is also possible here to transfer not pigment-containing suspensions but two-dimensional layers of a solution. These solutions may comprise substances which, after drying, constitute a barrier layer against the package contents (e.g. surfactants, builders, solvents, etc.) or else lower the water solubility of the film. The latter can ensure, inter alia, that said films do not go into solution prematurely and already release the package contents in the course of handling of the package.