WATER-SOLUBLE POLYMER FILMS OF ETHYLENE OXIDE HOMO- OR COPOLYMERS, CALENDERING PROCESS FOR THE PRODUCTION THEREOF AND THE USE THEREOF

Abstract

Described herein is a process for producing water soluble polymer films by low temperature calendering of a polymer composition including an ethylene oxide homo- or copolymer. Also described herein are polymer films obtainable by said process and methods of using the polymer films, in particular for the portionwise packaging of detergents and cleaners.

Claims

1. A process for producing a water-soluble or water-dispersible polymer film, comprising a) providing a polymer composition in powder or granular form comprising a water-soluble ethylene oxide homo- or copolymer P1), and b) subjecting the polymer composition provided in step a) to a calendering at a temperature below the melting point of the ethylene oxide homo- or copolymer P1) and substantially absent any extraneous solvent to obtain a polymer film.

2. The process according to claim 1, wherein the ethylene oxide homo- or copolymer P1) employed in step a) has a D50 value from 100 μm to 750 μm.

3. The process according to claim 1, wherein the ethylene oxide homo- or copolymer P1) employed in step a) has a number average molecular weight in the range from 10000 to 10000000 g/mol.

4. The process according to claim 1, wherein the polymer composition provided in step a) further comprises a polymer component P2) selected from the group consisting of polymer compositions obtainable by free-radical polymerization of a monomer composition M) which comprises at least one monomer A) selected from the group consisting of α,β-ethylenically unsaturated carboxylic acids, salts of α,β-ethylenically unsaturated carboxylic acids and mixtures thereof, in the presence of at least one (C.sub.8-C.sub.18-alkyl)polyoxyalkylene ether PE) having an average of 3 to 12 alkylene oxide units per molecule, 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 the group consisting of 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, copolymers comprising at least one copolymerized (meth)acrylic monomer selected from the group consisting of acrylic acid, methacrylic acid, salts thereof and mixtures thereof and at least one copolymerized hydrophobic monomer selected from the group consisting of C.sub.1-C.sub.8-alkyl esters of (meth)acrylic acid, C.sub.2-C.sub.10 olefins, styrene and α-methylstyrene, copolymers comprising at least one copolymerized maleic monomer selected from the group consisting of maleic acid, maleic anhydride, maleic salts and mixtures thereof and at least one copolymerized C.sub.2-C.sub.8 olefin, homo- and copolymers comprising at least one monomer comprising sulfonic acid groups, homo- and copolymers of acrylamide and/or methacrylamide, polyamino acids, water-soluble or water-dispersible polyamides, polyalkylene glycols, mono- or diethers of polyalkylene glycols, each being different from P1), and mixtures thereof.

5. The process according to claim 1, wherein the polymer composition provided in step a) further comprises at least one additive.

6. The process according to claim 1, wherein the calendering in step b) is effected at a temperature in a range from 10 to 80° C.

7. The process according to claim 1, wherein the calendering in step b) is effected by exerting a linear force in a range of 50 to 5000 N/mm.

8. The process according to claim 1, wherein the calendering in step b) is effected at a speed in a range of 0.05 m/min to 1000 m/min.

9. A polymer film obtainable by a process as defined in claim 1.

10. A method of using the polymer film as defined in claim 9, the method comprising using the polymer film as a washing and cleaning composition, for at least partial coating or ensheathing of washing and cleaning compositions, as a dishwashing composition or as a rinse aid, for at least partial coating or ensheathing of dishwashing compositions or for at least partial coating or ensheathing of rinse aids, as hygiene products, for at least partial coating or ensheathing of hygiene products, as disinfectants, for at least partial coating or ensheathing of disinfectants, for at least partial coating or ensheathing of personal care compositions, for at least partial coating or ensheathing of personal cleansing compositions, for at least partial coating or ensheathing of cosmetic compositions, as pharmaceutical compositions, for at least partial coating or ensheathing of pharmaceutical compositions, as crop protection compositions, for at least partial coating or ensheathing of crop protection compositions, for at least partial coating or ensheathing of bait traps, as food or animal feed packaging, as wetting agents, for at least partial coating or ensheathing of wetting agents, as packaging for textiles, as lamination films, or in composite systems (laminates).

11. A sheath or coating for a washing composition portion, cleaning composition portion or dishwashing composition portion, comprising the polymer film as defined in claim 9.

12. A washing or cleaning composition comprising: A) at least one sheath and/or coating comprising the polymer film as defined in claim 9, B) at least one surfactant, C) optionally at least one builder, D) optionally at least one bleach system, E) optionally at least one further additive, and F) optionally water.

13. A dishwashing composition comprising: Ga) at least one sheath and/or coating comprising the polymer film as defined in claim 9, Gb) optionally at least one complexing agent, Gc) at least one builder and/or cobuilder, Gd) at least one nonionic surfactant, Ge) optionally at least one component selected from the group consisting of bleaches, bleach activators and bleach catalysts, Gf) optionally at least one enzyme, Gg) optionally at least one further additive, and Gh) optionally water.

14. The process according to claim 1, wherein the ethylene oxide homo- or copolymer P1) employed in step a) has a number average molecular weight in a range from 25000 to 5000000 g/mol.

15. The process according to claim 1, wherein the polymer composition provided in step a) further comprises a polymer component P2) selected from the group consisting of copolymers comprising at least one copolymerized acrylic monomer selected from the group consisting of acrylic acid, acrylic salts and mixtures thereof, and at least one copolymerized maleic monomer selected from the group consisting of maleic acid, maleic anhydride, maleic salts and mixtures thereof.

16. The process according to claim 1, wherein the polymer composition provided in step a) further comprises at least one additive selected from the group consisting of nonionic, anionic, cationic and amphoteric surfactants, polymeric dispersants, builders, complexing agents, bleaches, bleach activators, bleach catalysts, enzymes, enzyme stabilizers, bases, corrosion inhibitors, defoamers and foam inhibitors, wetting agents, dyes, pigments, fragrances, fillers, tableting aids, disintegrants, thickeners, solubilizers, organic solvents, electrolytes, pH modifiers, perfume carriers, bitter substances, fluorescers, hydrotropes, antiredeposition agents, optical brighteners, graying inhibitors, antishrink agents, anticrease agents, dye transfer inhibitors, antimicrobial active ingredients, antioxidants, anti-yellowing agents, antistats, ironing aids, hydrophobizing and impregnating agents, antiswell and antislip agents, plasticizers, scavengers, polymers other than the polymer component P1) and the polymer component P2), agents for modification of gas permeability and water vapor permeability, glidants, slip agents and UV absorbers and mixtures thereof.

17. The process according to claim 1, wherein the calendering in step b) is effected at a temperature in a range from 15 to 70° C.

18. The process according to claim 1, wherein the calendering in step b) is effected by exerting a linear force in a range of 100 to 2500 N/mm.

19. The washing or cleaning composition according to claim 12, wherein the optionally at least one further additive E) is selected from the group consisting of enzymes, bases, corrosion inhibitors, defoamers, dyes, fragrances, fillers, tableting aids, disintegrants, thickeners, solubilizers, organic solvents, electrolytes, pH modifiers, perfume carriers, fluorescers, hydrotropes, antiredeposition agents, optical brighteners, graying inhibitors, antishrink agents, anticrease agents, dye transfer inhibitors, antimicrobial active ingredients, antioxidants, polymeric dispersants, antistats, ironing aids, hydrophobizing and impregnating agents, antiswell and antislip agents and UV absorbers.

20. The dishwashing composition according to claim 13, wherein the optionally at least one further additive Gg) is selected from the group consisting of anionic or zwitterionic surfactants, alkali carriers, polymeric dispersants, corrosion inhibitors, defoamers, dyes, fragrances, fillers, tablet disintegrants, organic solvents, tableting aids, disintegrants, thickeners and solubilizers.

Description

BRIEF DESCRIPTION OF FIG. 1

[0458] FIG. 1 shows the tension vs elongation in machine direction (MD) and transverse machine direction (TD) for the comparative example 1 (control sample) (lines 3 and 4) and example 1 according to the invention (lines 1 and 2).

EXAMPLES

[0459] The following abbreviations were used:

EO: ethylene oxide, PO: 1,2-propylene oxide,
PEO: polyethylene oxide

[0460] The weight-averaged molecular weight of the polymers was determined by gel permeation chromatography (GPC). The following instruments and chromatography methods were used for this purpose:

Standard: polyacrylic acid, neutralized
Eluent: 0.01 mol/I phosphate buffer (=10 Na.sub.2HPO.sub.4+1.8 KH.sub.2PO.sub.4+2.7 KCl+137 NaCl in mmol/1), pH=7.4, +0.01 M NaN.sub.3 in deionized water
Flow rate: 0.8 ml/min
Column set: 2 separating columns (I=30 cm each)
Column temperature: 35° C.

Detector: RID (Refractive Index Detector) Agilent 1200″

[0461] The following table 1 gives an overview of the commercial polyethylene oxide polymers P1) used in the examples.

TABLE-US-00001 TABLE 1 Molecular weight P1) Product name Supplier Abbreviation [kg/mol] 1 Pluriol E9000 BASF SE PEG10K 10 2 POLYOX WSR N 10 Dow Chemicals PEO100k 100 3 POLYOX WSR 205 Dow Chemicals PEO600k 600 4 POLYOX WSR N 12 K Dow Chemicals PEO1mio 1000 5 PEO 2 mio mv Sigma Aldrich PEO2mio 2000 Product: 372803 6 POLYOX WSR 301 Dow Chemicals PEO4mio 4000

Synthesis Example 1

[0462] Preparation of a polymer composition P2) with a molecular weight of 5330 g/mol from acrylic acid and a (C.sub.5-C.sub.18-alkyl)polyoxyalkylene ether with 7 ethylene oxide units per molecule in a weight ratio of 2:1. The initial charge was heated to 75° C. with stirring at 100 rpm. Then, feeds 1, 2 and 3 were metered in over 4 h and the reaction mixture was after-polymerized for a further hour. The mixture was then allowed to cool to room temperature. The polymer composition is produced in the form of a transparent and viscous solution.

TABLE-US-00002 Amount (% by Content Feed material weight) (%) Initial (C.sub.8-C.sub.18-Alkyl)polyoxyalkylene 24.00 100.00 charge ether Water.sup.a) 18.00 100.00 Feed 1 Acrylic acid 48.00 100.00 Feed 2 Initiator.sup.b) 0.34 100.00 Water.sup.a) 3.83 100.00 Feed 3 2-Mercaptoethanol 0.96 100.00 Sodium hypophosphite 2.62 55.00 Water.sup.a) 2.25 100.00 .sup.a)completely demineralized water .sup.b)2,2'-azobis(2-methylpropionamidine) dihydrochloride (CAS No. 2997-92-4)

[0463] The following table 2 gives an overview of the washing- and cleaning-active polymer compositions P2) and further tensides used as additives in the examples.

TABLE-US-00003 TABLE 2 Abbre- No. Material Product name Supplier viation 1 polymer P2) from — — PASC synthesis example 1 2 vinylpyrrolidone-vinyl Kollidon VA64 BASF SE PVP/VA acetate copolymer Fine Mw: 65000 g/mol 3 polyacrylic acid Sokalan PA 25 BASF SE PAA Mw: 5000 g/mol CL G 4 Carboxymethylcellulose WALOCEL CRT DOW CMC sodium salt 2000 PA Chemical Company 5 C.sub.13C.sub.15-oxo alcohol Lutensol AO7 BASF SE AO7 with 7 EO

Tensile Strength Measurement:

[0464] Films were cut into samples with dimensions of 20 mm×50 mm and conditioned, i.e. measured after storage for more than 40 h at 50% relative humidity and 23° C. Tensile strength was measured using a Zwick Roell material tester at a constant grip separation rate of 25 mm/min in alignment with ASTMD882-12 standardized test procedure.

Water Solubility:

[0465] The water-solubility of the polymer films was characterized using a standardized test method established by MonoSol LLC (MSTM-205, Monosol, Mar. 31, 2003). The time until first holes appear in the foil and the time until the foil completely separates from the slide support are subsequently referred to as disintegration time (t1) and release time (t2).

Film Thickness:

[0466] Film thickness was measured using a digital micrometer indicator (ID-H0530, Mitutoyo).

Comparative Example 1

[0467] As a control sample a polyethylene oxide film was prepared by a conventional film casting process. PEO600k was dissolved in deionized water by stirring over night at 40° C. The solution had a solid content of 10 wt. % and 0.5 wt. % Lutensol AO7 was added to improve wetting and reduce adhesion to the substrate. The polymer solution was knife coated on polyethylene terephthalate foil (Hostaphan RN100/100 μm) and dried by contact drying at 60° C. and ambient humidity. The obtained free standing polyethylene oxide foil was subsequently removed from the supporting polyethylene terephthalate substrate. The dry film thickness of the polyethylene oxide film was 64 μm and the dissolution times t1 and t2 (MonoSol method) were determined to be 15 s and 59 s, respectively.

Example 1 (According to the Invention)

[0468] A polyethylene oxide film was prepared by low temperature calendaring of a polyethylene oxide powder to prepare a film. The PEO600k powder was dosed manually onto a continuous polyethylene terephthalate substrate (Hostaphan RN100/100 μm) and metered with a coating knife (ZUA 2000.60, Zehntner) with a 1.4 mm gap setting. The powder was fed horizontally into a single roll pair calendar (GK300L, Saueressig) exerting a linear force of 880 N/mm at a speed of 1 m/min. The calender rolls were temperature controlled at 40° C. The material exited the calender as continuous film and the supporting polyethylene terephthalate substrate and the polyethylene oxide film were seperated. To achieve the desired film thickness the polyethylene oxide film was then repeatedly calendered without supporting substrate at 1325 N/mm and a web speed of 1 m/min. After 3 calendaring steps, a film thickness of 63 μm was reached and the dissolutions times t1=12 sec and t2=60 sec were measured (MonoSol method).

[0469] 1 shows a plot of the tension as a function of the elongation in machine direction (MD) and transverse maschine direction (TD) for comparative example 1 (control 1/cast film) and example 1 according to the invention (calendered film).

[0470] Whereas the comparative example shows significantly higher elongation at break (approx. 70% TD; approx. 120% MD), the film prepared according to the invention has a higher E-Modulus in the elastic range and a tensile strength that is orders of magnitude higher. The anisotropy shown by the difference in tensile strength in TD and MD indicates a strong orientation of the polymer film. Polymer chains are oriented due to shear forces caused by the deformation into a film. Once no more shear is applied, the oriented polymers may relax into a more isotropic state. The amount of orientation of the polymer and anisotropy in the final film depends on the absolute values of shear forces, the relaxation time and mobility during relaxation. The solid-state calendaring process according to the invention results in significantly higher shear forces due to the higher forces employed to deform the solid polymer. Polymer mobility is high while a cast film dries and a melt film solidifies. In contrast, relaxation is inhibited in solid state calendared films.

[0471] Table 3 summarizes values for tensile strength and elongation at break for conventionally produced films taken from U.S. Pat. No. 3,465,070 and compared to measured values for cast (comparative example 1) and solid state calendared films (example 1).

TABLE-US-00004 TABLE 3 Overview of mechanical properties of conventionally produced PEO films compared to the solid state calendared films Tensile Elongation strength at (Mpa) break (%) Source Method Material MD TD MD TD US3465070 extruded 600 k 21.9 13.9 596 557 PEO US3465070 conventionally 600 k 14.8 13.4 958 888 calendered PEO US3465070 cold rolled 600 k 57.8 16.0 290 858 from extruded PEO foil comp. ex. 1 cast 600 k 10.4 10.1 123 66 PEO example 1 calendered in 600 k 101.0 24.1 51 18 solid state PEO

[0472] The combination of higher shear and less relaxation results in higher tensile strength, more anisotropic behavior, and lower elongation at break for the solid-state calendared films.

Example 2: Molecular Weight

[0473] Films from polyethylene oxides with various molecular weights were prepared by the method described in Example 1. Tensile strength and weight averaged molecular weight is shown in table 4. As expected, tensile strength increases with molecular weight. All films were calendared using the same method and linear forces described in Example 1. To achieve a similar film thickness of 100 μm, the number of calendaring steps had to be varied with molecular weight. Whereas only 2 calendaring steps were necessary for MW≤600 kg/mol, 4 and 5 steps were required to reach 100 μm for Example 2D and 2E, respectively.

TABLE-US-00005 TABLE 4 Overview of tensile strength of solid-state calendared PEO films with variable molecular weight Molecular Tensile weight strength Example kg/mol MPa Example 2A 10 1.7 Example 2B 100 33.1 Example 2C 600 64.8 Example 2D 2000 129.3 Example 2E 4000 131.6

[0474] As shown in Table, tensile strength increases degressively with the molecular weight. Higher absolute values can be achieved for all materials if the number of calendaring steps or the linear force is further increased. Examples 2A to 2E show that the method according to the invention is applicable to PEO grades of various molecular weights.

Example 3: Use of Functional Additives

[0475] In principle, no additives (such as tensides, softeners, etc.) are required to form water soluble foils from PEO by calendaring. It may however be desired to include at least one functional additive. As shown in Table, additivities is readily applicable to PEO/additive mixtures with various compositions. The weight content of PEO was kept constant at 20 wt. %. The calendaring procedure described in Example 1 was used.

TABLE-US-00006 TABLE 5 Overview of different functional additives introduced into PEO films. Various mixtures of Polyacrylic acid (PAA), vinylpyrrolidone-vinyl acetate copolymer (PVP/VA), Na-Carboxymethylcellulose (CMC) and tenside (C.sub.13C.sub.15-oxo alcohol with 7 EO, Lutensol AO7) were added to PEO and calendared into polymer films. Film Tensile thickness strenght Example Composition [μm] N/mm.sup.2 Example 3A 80% PAA, 20% PEO, +0.5% AO7 140 3.41 Example 3B 60% PAA, 20% PEO, 10% PVP/VA, 80 2.75 10% CMC Example 3C 60% PAA, 20% PEO, 10% PVP/VA, 120 5.02 10% CMC, +0.5% AO7

[0476] There is no intrinsic limitation to the mixing ratio between additive and polyethylene oxide. PEO content and tensile strength of various mixing ratios are shown in Table 5. Tensile strength reduces with PEO100k content from 7.7 MPa at 0.25 wt. % PEO to 3.7 MPa at 3.7 wt. %. Depending on the composition, the films may become opaque at high PEO content.

[0477] Here all mixtures were prepared using the calendaring method described in Example 1 with identical number of calendaring steps, whereas film thickness was not kept constant. Therefore, the higher molecular weight PEO films had a slightly higher film thickness but similar tensile strength compared to the PEO100k.

TABLE-US-00007 TABLE 1 Calendared films with various mixing ratios of Additive (PASC) to Polyethylene oxide with a molecular weight of 100 kg/mol (PEO100k) and 1000 kg/mol (PEO1mio). PEO Tensile content strength Experiment Material wt. % MPa Example 4A PASC:PEO100k 0.25 7.7 Example 4B PASC:PEO100k 0.075 2.2 Example 4C PASC:PEO100k 0.125 3.9 Example 4D PASC:PEO1mio 0.075 2.4 Example 4E PASC:PEO1mio 0.25 6.3 Example 45 PASC:PEO1mio 0.125 3.7

Comparison to Commercial Polyvinyl Alcohol Foil:

[0478] To show the applicability of the prepared films according to the invention in a unit dose packaging application commercial detergent capsules (DenkMit, DM Drogeriemarkt) were bought and the detergent fluent was removed. Pouches of calendared PEO foil were then prepared using a commercial heat sealing apparatus and filled with detergent fluid. The pouches were dissolved in a stirred beaker of demineralized water at 30° C. PEO600k pouches with a film thickness of 100 μm were dissolved after 20 min which is only 4 min slower compared to the commercial PVOH pouches (16 min). As rate of dissolution depends on film thickness as well as molecular weight of the PEO, the calendared PEO foil can be tuned to perform similar to commercial PVOH with respect to dissolution rate.