ITRM20120627A1 - FORMULATION OF HYDRO-SOLUBLE AND BIODEGRADABLE ADHESIVE FOR HIGH HUMIDITY AND GAS BARRIER PERFORMANCES FOR TWO-LAYER OR MULTI-LAYER PACKAGING FILM WITH CELLULOSIC MATRIX OR RELATED COMPOSITES. - Google Patents

Description

Formulation of water-soluble and biodegradable adhesive with high moisture and gas barrier performance for two-layer or multilayer cellulosic matrix packaging film or relative composites

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The present invention relates to a formulation of biodegradable water-soluble adhesive with high moisture and gas barrier performance for single or multilayer cellulosic matrix packaging films or relative composites.

More in detail, the invention relates to a formulation of the above type, based on poly (vinyl alcohol) (PVA) usable in the production of laminated films with two or more layers with a simple or composite cellulose matrix.

As is well known, polyvinyl alcohol or poly (vinyl alcohol), commonly referred to in abbreviated form as PVA (or PVOH), is a polymer that is obtained by hydrolysis of polyvinyl esters. Furthermore, PVA is one of the few hydrocarbon chain polymers that exhibits a certain degree of solubility in water, which varies according to its degree of hydrolysis (HD). The degree of hydrolysis and dynamic viscosity in a 4% aqueous solution (in accordance with DIN 53015) are the most significant properties through which to characterize PVA.

In particular, PVA is not obtained by direct polymerization of the corresponding hydroxyethylene or vinyl alcohol monomer (CH2 = CHOH), as the latter tends to quantitatively convert into the structural isomer (tautomer) acetaldehyde (CH3CHO) which is thermodynamically more stable.

Industrially, PVA is then produced from poly (vinyl acetate) (PVAc) through alkaline deacetylation with methanol, which leads to the formation of methyl acetate and PVA, according to the scheme:

Commercial PVA products are commonly made up of macromolecular chains containing percentages of repeating units that see the number of monomer units formally derived from vinyl alcohol, indicated with q, between 1 and 30 and, consequently, the number of monomer units formally derived from vinyl acetate, indicated with p, between 99 and 70, with a relative distribution of the two repeating units more or less random depending on the type of process used during the hydrolysis of the PVAc.

Samples characterized by a high degree of hydrolysis (HD = 98Ã · 99%) have a considerably slower dissolution kinetics in aqueous environment than PVA samples having a low or medium-low degree of hydrolysis (HD = 72Ã · 88%) which they are easily soluble even in cold or lukewarm water. In fact, the solubility of PVA can also be correlated to the degree of crystallinity of the material, which is maximum for completely hydrolyzed samples (HD> 99%) regardless of the level of microtactivity.

As far as its applications are concerned, PVA, comparable in cost and performance to a technopolymer, has various and well-known uses [â € œPolyvinyl alcohol Developmentsâ €, C.A. Finch, John Wiley & Sons, 1992] which include applications in the paper industry, in textiles, for the production of water-soluble packaging films (single-dose for detergents, hospital bags, bags for pesticides), such as water-based adhesives , as binders in lithographic applications, in the ceramic industry, in the production of inks and even in the petroleum sector [international application PCT / IT2012 / 000341, on behalf of the same applicant].

PVA emulsions with different degrees of hydrolysis and mixtures with PVAc have been described for the production of water-based adhesives for the packaging of wooden surfaces for the production of plywood, in combination with diisocyanates and other components capable of providing adhesives to reticular structure (cured).

C.A. Finch [â € œPolyvinyl alcohol Developmentsâ €, C.A. Finch, John Wiley & Sons, 1992] also describes a wide variety of adhesives for paper and cardboard, referring to formulations based on PVA with other macromolecular components of natural, semi-synthetic and synthetic origin. In particular, this document describes some formulations with particular characteristics of mechanical resistance when applied to multilayer systems and gloss properties when applied as surface coatings of the paper (coating).

In this context, the solution according to the present invention is inserted, which aims to provide a formulation of biodegradable water-soluble adhesive which, despite its water-solubility characteristics, allow for a poor ability to act as a barrier to humidity, nevertheless, used as a mono or multilayer cellulose matrix packaging film unexpectedly presents high barrier performances to humidity and gases.

In other words, the adhesive formulation according to the present invention, although it consists of high molecular weight components soluble in water and capable of providing products sensitive to humidity, if used as a coupler for cellulosic sheets or laminates and related cellulosic-based composites , has high barrier properties to humidity and gases.

These and other results are obtained according to the present invention by proposing a water-soluble structural adhesive with high performance in terms of barrier properties to humidity and gases, when used for the surface treatment or as a couplant of pure cellulose-based laminated sheets or composites. cellulosic matrix, consisting of a formulation of low and high molecular weight components, characterized by high solubility in water, containing poly (vinyl alcohol) as the major component and linear or branched polyols with high, medium and high molecular weight and low and high additives molecular weight that preserve its rancidity.

The aim of the present invention is therefore to provide a formulation of biodegradable water-soluble adhesive for single or multilayer cellulosic matrix packaging film which allows to obtain the technical results previously described.

A further aim of the invention is that said formulation can be realized with substantially contained costs.

Not least object of the invention is that of realizing a formulation of biodegradable water-soluble adhesive for two or more layers cellulosic matrix packaging film which is substantially simple, safe and reliable.

A first specific object of the present invention therefore forms a formulation of water-soluble and biodegradable adhesive comprising a copolymer consisting of monomer units formally derived from vinyl alcohol (VA) and vinyl acetate (VAc) and degree of hydrolysis (HD) varying between 70 and 99%, that is, with a percentage of VAc units between 70 and 99% and correspondingly a percentage of VAc units in complement between 1 and 30%.

In particular, according to the invention, said formulation of water-soluble and biodegradable adhesive has a weight average molecular weight (<Mw>) between 12kDa and 220kDa and preferably between 14kDa and 150kDa; a dynamic viscosity in a 4% aqueous solution between 2 and 58mPas and preferably between 3 and 25 mPas (measured by a Brookfield-type rotational viscometer at a temperature of 20 ° C (in accordance with DIN 53015)).

Preferably, according to the present invention, said degree of hydrolysis (HD) is comprised between 75 and 95% and more preferably between 80 and 90%.

In particular, again according to the invention, said formulation of water-soluble and biodegradable adhesive further comprises an anti-fermentation agent, preferably selected from: monopropylene glycol (1,2-propanediol), polyethylene glycol 200 (with an average degree of oligomerization equal to 4), polyethylene glycol 400 (with an average degree of oligomerization equal to 8Ã 9), polyvinipyrrolidone (PVP) PK30 (<Mw> 60kDa), glycerol, chitosan (degree of acetylation 20%, <Mw> 75 kDa), chitosan (degree of acetylation 15 %, <Mw> 55 kDa) and their mixtures; an anti-foaming agent, preferably a mixture based on vegetable oils, alkoxylated compounds, silica and non-ionic emulsifiers (Agitan® 271, produced by MÃ1⁄4nzing); an anticoagulant, preferably urea; a mixture based on chloromethylisothiazolinone / methylisothiazolinone and bromonitropropandiol (Parmetol® A28 S, produced by SchÃ1⁄4lke &Mayr); a mixture based on chloromethylisothiazolinone / methylisothiazolinone and dimethylol-urea / ethylenedioxydimethanol (Parmetol® DF35, produced by SchÃ1⁄4lke &Mayr; calcium chloride; magnesium chloride; calcium thiosulfate.

A second specific object of the present invention also forms the use of the previously defined formulation of water-soluble and biodegradable adhesive for the production of cellulosic matrix films with two or more layers.

The effectiveness of the formulation of biodegradable water-soluble adhesive for cellulosic matrix packaging film with two or more layers of the present invention is evident, which although constituted by high molecular weight components soluble in water and capable of providing products sensitive to humidity , if used for the surface treatment or as a couplant of cellulosic sheets or laminates and related cellulosic-based composites, it has high barrier properties to humidity and gases.

The single or multilayer cellulosic products prepared from cellulose-based sheets and laminates treated or glued with the adhesive formulation according to the present invention are characterized by extraordinary and unexpected moisture barrier properties, considering the hydrophilic nature of the various components used in the adhesive formulation.

Furthermore, as expected, the adhesive formulation according to the present invention has excellent properties of resistance to fats, oils and aliphatic and aromatic hydrocarbon solvents as well as strong barrier properties to gases (nitrogen, oxygen and gaseous C1-C4 hydrocarbons).

The adhesive formulation of the present invention has structural characteristics towards paper and cardboard with a cellulosic matrix and is also completely biodegradable in aqueous environment, in accordance with the standards EN ISO 148552 2004, EN 14048 regarding biodegradability in aqueous environment, and therefore can be identified as high performance â € œbi-adhesiveâ € in terms of barrier to humidity and gases.

Furthermore, this structural bioadhesive formulation, thanks to the food compatibility of its components, can also be used for the production of single or multilayer paper and cardboard packaging for containing food for human and animal consumption in the form of powders or granules. sensitive to humidity, oxygen and oils as well as for the containment / packaging of organic (vegetable flours) or inorganic powders sensitive to humidity such as pesticides, mortars and cements.

The increase in the barrier properties against humidity that can be obtained on a paper surface by treatment with the bioadhesive formulation object of the present invention has been shown to be approximately an order of magnitude (10 times) greater than the barrier to moisture. Surface humidity as it is in the absence of coupling with the bioadhesive formulation of the invention.

The present invention will be described below for illustrative but not limitative purposes, with particular reference to some illustrative examples and the attached figures, in which:

- Figure 1 shows a bar diagram of the values of the permeability to humidity of a double-layer paper sheet and of various samples of the same paper support after treatment with different quantities of adhesive made according to a preferred embodiment of the adhesive formulation object of the present invention, described in example 2;

- figure 2 shows the trend of the absorption coefficient (Ceq) as the water vapor activity varies, and

- figure 3 shows the trend of the diffusion coefficient (D) as the water vapor activity varies.

In the following examples some specific formulations will be presented, all made starting from a copolymer consisting of monometric units formally derived from vinyl alcohol (VA) and vinyl acetate (VAc) and degree of hydrolysis (HD) variable between 70 and 99%, i.e. with a percentage of VA units varying between 70 and 99% and correspondingly a percentage of VAc units in complement between 30 and 1%.

The degree of hydrolysis HD is preferably between 75 and 95% and more preferably between 80 and 90%.

The weight average molecular weight (<Mw>) of the matrices underlying the various formulations used as adhesives for paper varies preferably between 12kDa and 220kDa and more preferably between 14kDa and 150kDa.

Correspondingly, the dynamic viscosity in a 4% aqueous solution is preferably between 2 and 58 mPas and more preferably between 3 and 25 mPas (as measured by a Brookfield-type rotational viscometer) at a temperature of 20 ° C (according to the DIN standard 53015).

Example 1

1kg of a formulation, hereinafter referred to as `` type A bio-adhesive '', was prepared according to the following procedure: 123g of PVA was added to a) in a beaker containing 770mL of deionized water at room temperature (T = 25 ° C) with HD 98% and viscosity 55mPas, b) 30g of monopropylene glycol (1,2-propanediol), c) 30g of polyethylene glycol 200 (average degree of oligomerization equal to 4), d) 30g of glycerol, e) 5g of a mixture of non-ionic alkoxylated compounds (Agitan® 290, produced by MÃ1⁄4nzing) as antifoam, f) 2g of a mixture based on chloromethylisothiazolinone / methylisothiazolinone and bromonitropropandiol (Parmetol® A28 S, produced by SchÃ1⁄4lke & Mayr) as an antifermentative ) 1g of urea as an anticoagulant. After adding all the components of the formulation, the temperature of the water was gradually raised up to 65 ° C and kept stirring for about an hour until a homogeneous solution was obtained which can be stored in plastic containers (e.g. PE-based example).

Example 2

Following the procedure described in example 1, a formulation called â € œbiadhesive type Bâ € weighing 2kg was prepared, consisting of the following ingredients: a) 1450g of deionized water, b) 356g of PVA with HD 88% and viscosity 4mPas, c) 62g of glycerol, d) 42g of polyethylene glycol 200 (average degree of oligomerization equal to 4), e) 42g of monopropylene glycol (1,2-propanediol), f) 20g of a mixture of non-ionic alkoxylated compounds (Agitan® 290, produced by MÃ1⁄4nzing) as antifoam, g) 20g of urea as anticoagulant, h) 4g of a mixture based on chloromethylisothiazolinone / methylisothiazolinone and bromonitropropandiol (Parmetol® A28 S, produced by SchÃ1⁄4lke & Mayr) and 4g of a mixture based on chloromethylisothiazolinone / methylisothiazolinone and dimethylol-urea / ethylenedioxydimethanol (Parmetol® DF35, produced by SchÃ1⁄4lke & Mayr) as antifermentatives.

Example 3

Following the procedure described in example 1, a formulation called `` type C adhesive tape '' was prepared with a weight of 1kg consisting of the following ingredients: a) 710g of deionized water, b) 200g of PVA with HD 96% and viscosity 3mPas, c) 30g of glycerol, d) 25g of polyethylene glycol 200 (average degree of oligomerization equal to 4), e) 24g of monopropylene glycol (1,2-propandiol), f) 2g of a mixture based on chloromethylisothiazolinone / methylisothiazolinone and bromonitropropanediol (Parmetol® A28 S, produced by SchÃ1⁄4lke & Mayr) and 2g of a mixture based on chloromethylisothiazolinone / methylisothiazolinone and dimethylol-urea / ethylenedioxydimethanol (Parmetol® DF35, produced by SchÃ1⁄4lke & Mayr) as anti-fermentatives) a mixture based on vegetable oils, alkoxylated compounds, silica and non-ionic emulsifiers (Agitan® 271, produced by MÃ1⁄4nzing) as antifoam and h) 5g of magnesium chloride as anticoagulant.

Example 4

Following the procedure described in example 1, a formulation called `` type D adhesive tape '' was prepared, weighing 3kg, consisting of the following ingredients: a) 2280g of deionized water, b) 390g of PVA with HD 92% and viscosity 30mPas, c) 120g of polyethylene glycol 200 (average degree of oligomerization equal to 4), d) 75g of glycerol, e) 75g of monopropylene glycol (1,2-propanediol), f) 30g of a mixture of non-ionic alkoxylated compounds ( Agitan® 290, produced by MÃ1⁄4nzing) as antifoam, g) 24g of calcium chloride as anticoagulant and h) 6g of a mixture based on chloromethylisothiazolinone / methylisothiazolinone and dimethylol-urea / ethylenedioxydimethanol (Parmetol® DF35, produced by SchÃ1⁄4 ) as an antifermentative.

Example 5

Following the procedure described in example 1, a formulation called `` type E bleaching adhesive '' was prepared with a weight of 1kg consisting of the following ingredients: a) 755g of deionized water, b) 180g of PVA with HD 79% and viscosity 15mPas, c) 30g of polyethylene glycol 400 (average degree of oligomerization equal to 8Ã 9), d) 10g of glycerol, e) 10g of a mixture based on chloromethylisothiazolinone / methylisothiazolinone and bromonitropropandiol (Parmetol® A28 S, produced by SchÃ1⁄ 4lke & Mayr) as an anti-fermentative, f) 10g of a mixture of non-ionic alkoxylated compounds (Agitan® 290, produced by MÃ1⁄4nzing) as an antifoam and g) 5g of calcium thiosulfate as an anticoagulant.

Example 6

Following the procedure described in example 1, a formulation called â € œf-type adhesive tapeâ € was prepared with a weight of 2 kg consisting of the following ingredients: a) 1520g of deionized water, b) 320g of PVA with 88% HD and viscosity 18mPas, c) 50g of polyethylene glycol 200 (average degree of oligomerization equal to 4), d) 50g of glycerol, e) 20g of chitosan (degree of acetylation 15%, <Mw> 63kDa) as an antifermentative, f) 20g of a mixture of non-ionic alkoxylated compounds (Agitan® 290, produced by MÃ1⁄4nzing) as an antifoam and g) 20g of magnesium chloride as an anticoagulant.

Example 7

Following the procedure described in example 1, a formulation called â € œbiadhesive type Gâ € was prepared with a weight of 1.5 kg consisting of the following ingredients: a) 1050g of deionized water, b) 345g of PVA with HD 72% and viscosity 6mPas, c) 30g of polyethylene glycol 400 (average degree of oligomerization equal to 8Ã 9), d) 30g of glycerol, e) 15g of chitosan (degree of acetylation 15%, <Mw> 55 kDa) as antifermentative, f ) 15g of a mixture of non-ionic alkoxylated compounds (Agitan® 290, produced by MÃ1⁄4nzing) as an antifoam and g) 15g of magnesium chloride as an anticoagulant.

Example 8

Following the procedure described in example 1, a formulation called `` type H adhesive tape '' was prepared weighing 1kg and consisting of the following ingredients: a) 730g of deionized water, b) 210g of PVA with 88% HD and viscosity 5mPas, c) 20g of polyvinipyrrolidone (PVP) PK30 (<Mw> 60kDa), d) 18g of polyethylene glycol 200 (average degree of oligomerization equal to 4), e) 10g of calcium chloride as anticoagulant, f) 5g of a mixture based on chloromethylisothiazolinone / methylisothiazolinone and bromonitropropandiol (Parmetol® A28 S, produced by SchÃ1⁄4lke & Mayr) and 5g of a mixture based on chloromethylisothiazolinone / methylisothiazolinone and dimethylol-urea / ethylenedioxidimethanol produced by Mayr and g) 2g of a blend based on vegetable oils, alkoxylated compounds, silica and non-ionic emulsifiers (Agitan® 271, produced by MÃ1⁄4nzing) as an antifoam.

Example 9

Following the procedure described in example 1, a formulation called â € œbiadhesive type Iâ € weighing 2kg was prepared, consisting of the following ingredients: a) 1460g of deionized water, b) 400g of PVA with HD 99% and viscosity 5mPas, c) 60g of polyvinipyrrolidone (PVP) PK30 (<Mw> 60kDa), d) 40g of polyethylene glycol 200 (average degree of oligomerization equal to 4), e) 20g of chitosan (degree of acetylation 20%, <Mw> 75kDa ) as an antifermentative, f) 20g of urea as an anticoagulant and g) 4g of a mixture based on vegetable oils, alkoxylated compounds, silica and non-ionic emulsifiers (Agitan® 271, produced by MÃ1⁄4nzing) as an antifoam.

Example 10.

Samples of paper treated with the water-soluble and biodegradable adhesive object of this invention were made by flexographic printing by placing the adhesive in the stations where the color is normally deposited.

In particular, various samples obtained by using the formulations described in examples 2, 7 and 8 and respectively denominated formulated type â € œBâ €, formulated type â € œGâ € and formulated type â € œHâ € were created and characterized.

Example 11. Method for measuring permeability The paper samples treated with the adhesive made according to example 10 were cut into rectangles of 5mm x 15mm, weighing between 25 and 30mg, and suspended on a quartz microbalance ( which extends by 15 cm / mg) in a glass column thermostated at 30 ° C. After creating a vacuum in the column for 24 hours, to dehydrate the samples, water vapor was then introduced at activities (a = w / w) of 0.2, 0.4 and 0.6. Then, with a catheter, the weight gain of the samples was followed over time, until reaching equilibrium, when the weight does not change within 12 hours. The absorption value, indicated with Ceqe measured in gH2O / 100g sample, which was measured at the three activities is shown in figure 1 where the samples called â € œwhiteâ €, â € œ4Bâ €, â € œ4Hâ €, â € œ4Gâ € and â € œ3Bâ € respectively refer to the sheet of untreated paper as it is, to the treated support using 4 flexographic stations containing the formulation â € œBâ €, 4 flexographic stations containing the formulation â € œGâ €, 4 flexographic stations containing the formulation â € œHâ € and 3 flexographic stations containing the formulation â € œBâ € respectively. Then, the value of the concentration Ctal time t on Ceqin function of the root of the time is plotted. If the trend up to values of 0.5 is linear, the behavior is Fickian and it is possible to obtain, from the angular coefficient, the diffusion coefficient D, expressed in cmq / s, relating to the specific activity, as shown in the figure 2, according to the report:

Ct / Ceq = 4 / d√Dt / pi

Plotting the log (D) values as a function of Ceqsi obtains a linear trend that allows to extrapolate a thermodynamic coefficient D0. The permeability P is therefore obtained from the product of Ceq for diffusion, according to the relation:

P = Ceqx D

In Figure 3, the values used for permeability were absorption and diffusion measured at water activity values equal to 0.6. The permeability calculated in correspondence with this water activity value is expressed on the basis of the units of measurement cm <3> (STP) · cm · cm <-2> · atm <-1> · s <-1>].

In particular, confirming the above, the graph in figure 3 shows the values of the permeability to water vapor (measured at a water absorption and activity value = 0.6) of a double-layer paper sheet normally used for the packaging of cements and cementitious mortars (indicated as â € œwhiteâ € in the graph) and other different samples of double-layer paper used for the same type of applications, having the same thickness after treatment with the double-sided adhesive described in example 2 and called â € œbiadhesive type Bâ € homogeneously distributed on the cellulosic surface in a quantity equal to 10 g / m <2>.

This reduction in the permeability coefficient is completely consistent with the trend of the absorption coefficient (Ceq) and of the diffusion coefficient (D) as the water vapor activity varies, as reported respectively in the graphs of Figures 1 and 2 .

Both Ceq and D values are, in fact, for all the samples of double-layer paper treated with type B double-sided tape, well below the characteristic values of â € œwhiteâ €. This trend is also much more pronounced in correspondence with high values of water vapor activity (a = 0.4Ã · 0.6).

The permeability (P) of the reference sample (PR) passes from a value of about 6x10 <-7> to values of P between 5.9x10 <-8> and 7.9x10 <-8> for the samples treated with the bio-adhesive type B, confirming a decrease in permeability to humidity, and therefore an increase in its barrier properties, approximately 10 times higher (PR / P = 5.6x10 <-7> / 5.4x10 <-8> = ∠¿8-10).

The present invention has been described by way of illustration, but not of limitation, according to its preferred embodiments, but it is understood that variations and / or modifications may be made by those skilled in the art without thereby departing from the relative scope of protection. as defined by the appended claims.

Claims (12)

CLAIMS 1) Formulation of water-soluble and biodegradable adhesive comprising a copolymer consisting of monomer units formally derived from vinyl alcohol (VA) and vinyl acetate (VAc) with a degree of hydrolysis (HD) ranging from 70 to 99%, i.e. with a percentage of VA units included between 70 and 99% and correspondingly a percentage of VAc units to complement between 1 and 30%. 2) Formulation of water-soluble and biodegradable adhesive according to claim 1, characterized in that it has a weight average molecular weight (<Mw>) comprised between 12kDa and 220kDa and preferably between 14kDa and 150kDa. 3) Formulation of water-soluble and biodegradable adhesive according to claim 2, characterized in that its dynamic viscosity in a 4% aqueous solution is between 2 and 58mPas and preferably between 3 and 25 mPas (measured by a Brookfield-type rotational viscometer at temperature of 20 ° C (in accordance with DIN 53015 standard)). 4) Formulation of water-soluble and biodegradable adhesive according to any one of the preceding claims, characterized in that said degree of hydrolysis (HD) is comprised between 75 and 95% and preferably between 80 and 90%. 5) Formulation of water-soluble and biodegradable adhesive according to any one of the preceding claims, characterized in that it further comprises an anti-fermentation agent. 6) Formulation of water-soluble and biodegradable adhesive according to claim 5, characterized in that said anti-fermentative agent is chosen from: monopropylene glycol (1,2-propanediol), polyethylene glycol 200 (with an average degree of oligomerization equal to 4), polyethylene glycol 400 (with average degree of oligomerization equal to 8Ã 9), polyvinipyrrolidone (PVP) PK30 (<Mw> 60kDa), glycerol, chitosan (degree of acetylation 20%, <Mw> 75 kDa), chitosan (degree of acetylation 15%, <Mw> 55 kDa) and their mixtures. 7) Formulation of water-soluble and biodegradable adhesive according to any one of the preceding claims, characterized in that it further comprises an anti-foaming agent. 8) Formulation of water-soluble and biodegradable adhesive according to claim 7, characterized in that said antifoam agent is a mixture based on vegetable oils, alkoxylated compounds, silica and non-ionic emulsifiers (Agitan® 271, produced by MÃ1⁄4nzing). 9) Formulation of water-soluble and biodegradable adhesive according to any one of the preceding claims, characterized in that it further comprises an anticoagulant. 10) Formulation of water-soluble and biodegradable adhesive according to claim 9, characterized in that said anticoagulant is urea. 11) Formulation of water-soluble and biodegradable adhesive according to any one of the preceding claims, characterized in that it further comprises a mixture based on chloromethylisothiazolinone / methylisothiazolinone and bromonitropropandiol (Parmetol® A28 S, produced by SchÃ1⁄4lke &Mayr); a mixture based on chloromethylisothiazolinone / methylisothiazolinone and dimethylol-urea / ethylenedioxydimethanol (Parmetol® DF35, produced by SchÃ1⁄4lke &Mayr; calcium chloride; magnesium chloride; calcium thiosulfate. 12) Use of the water-soluble and biodegradable adhesive formulation defined in claims 1-11 for the production of single or multilayer cellulosic matrix films.