The present invention relates to modification of the surfaces of synthetic polymers. In particular, the present invention concerns a method of treating polymers surfaces according to the preamble of claim 1.

The present invention also concerns novel objects of synthetic polymers according to the preamble of claim 21.

Plastics and other synthetic polymeric materials predominantly composed of, or at least having a surface formed by, thermoplastic or thermosetting polymers, are non-compatible with many natural materials due to the fact that the plastic are hydrophobic (water- repellent), whereas natural material typically are hydrophilic.

Methods of changing the surface properties of synthetic, typically hydrophobic, polymers are known in the art.

Schroeder et al. have described pretreatment of nonwoven polypropylene fabrics with argon plasma in the presence of different methacrylate monomers, to facilitate an enzyme- induced postgrafting of guaiacol sulfonic acid as a phenolic compound onto the surface using laccased enzymes (M. Schroeder, e. Fatarella, J. Kovac, G. M. Guebitz and V. Kokol, "Laccase-Induced Grafting on Plasma-Pretreated Polypropylene", Biomacromolecules 2008, 9, 2735-2741.)

The known method uses a coarse method of activating the surface to introduce a tag, methacrylate, which is then used as a binding site for the phenolic compound which is grafted onto the surface. Naturally, the plasma treatment already as such modifies the surface making it more hydrophilic, which indicates that surface bonds may be degraded. The pretreated surface will be uneven, and grafting will be possible only at the specific sites, where the methacrylate monomer is attached.

A similar technological approach is disclosed in International Published Patent Application WO 2009/019567. The known document describes a process for functionalizing polymer materials, comprising a first step wherein the polymer material is grafted with a functionalized monomer having at least one functional group and a second step wherein the so-treated polymer material is reacted with a functionalized organic compound. The disadvantages are the same as those of the method discussed above.

The present invention aims at providing a method of modifying the surface of a synthetic polymer, e.g. a thermoplastic or thermosetting object, such as a fibre, film or sheath, to impart on it desired properties foreign to it. In particular, it is an aim of the present invention to provide a generic modification method for improving the technical properties of synthetic polymers, such as polyesters and polyolefϊns.

The present invention is based on a combination of low-energy physical methods with chemo-enzymatic functionalisation to achieve a modified surface.

In a first stage, the surface energy of the object material is increased by an essentially physical treatment and in a second stage the activated surface is contacted with a phenolic material and a suitable enzymatic catalyst for bonding of the phenolic material to the activated surface. The bonding is achieved by radical-radical coupling.

As a result, the surface modified by the invention will exhibit properties which at least in part are foreign to that of the unmodified surface.

More specifically, the present invention is characterized by what is stated in the characterizing part of claim 1.

The products according to the present invention are characterized by what is stated in the characterizing part of claim 21 and the uses thereof by what is stated in claim 25.

Considerable advantages are obtained by the invention. The modified fibres or films or can be exploited in versatile way for technical textiles, fabrics and gauzes and non-wovens to achieve improved functionality, durability and user- friendliness.

In one preferred embodiment, the modification according to the invention comprises bonding of functional molecules, preferably directly, onto the surface of a hydrophobic polymer material, in order to modify surface properties, such as wetting, antistatic, soil repellent, adherence or antimicrobial properties. The functional molecules are so firmly bonded to the surface that they cannot essentially be removed afterwards by washing, e.g. with water or another aqueous medium.

In another preferred embodiment, the phenolic modifying chemical and an enzyme are applied by spraying on a discrete part of the activated surface. This embodiment allows for the modification of the surface only at discrete areas. This reduces the consumption of the chemicals and allows for rapid and continued treatment. Printed circuits and diagnostic substrates are particularly interesting applications for this embodiment.

Next, the invention will be examined more closely with the aid of a detailed description and with reference to the attached drawings, in which

Figure 1 gives a schematic depiction of an ozonation equipment used in one embodiment of the present invention, and Figures 2a and 2b show photographs of water on an untreated (Fig. 2a) and on FA-starch functionalized PP film sample (Fig. 2b).

As was briefly discussed above, the present invention comprises a two-step method in which a surface of a thermoplastic or a thermosetting polymer or a similar synthetic polymer is first subjected to surface-specific activation to provide an activated surface on the product, and then the activated surface of the product is modified by chemo-enzymatic functionalisation.

The treated surface can have any suitable shape, such as the surface of a fibre, a fibril, a film or a sheath, a particle of a pigment or a similar product. The surface can have a geometrically regular or irregular surface. Examples of regular surfaces include planar, curved, cylindrical and spherical. Irregular surfaces include combinations of generally regular surfaces with irregularities such as open pore of various lengths.

Any primarily synthetic, non-natural, polymeric material is interesting as a starting material for the present invention. Such materials have primarily a hydrophobic surface which limits its compatibility with natural materials which primarily are hydrophilic. Examples of hydrophobic polymeric are thermoplastic material, thermosetting materials and combinations of two or more of the thermoplastic materials, of the thermosetting materials, as well of these materials mixed with additives, fillers, reinforcing components and other materials which modify the properties thereof. Particularly interesting polymers are polyolefms, polystyrene, polyesters, polycarbonates, polyamides, poly(alk)acrylates, polyurethanes, kopolymers of ethylene and vinyl acetate and ethylene and vinyl alcohol, fluorinated polyolefms and other fluoroplastics, ionomers, liquid crystal polymers and other materials having a rigid backbone, such polyaromatics, including polyaniline, optionally doped, hybrid organic-inorganic materials, such as polysiloxanes, optionally bearing organic substituents and residues.

The thermosetting materials include polymers with cross-links within the polymer material. The thermoset is produced from a prepolymer in a soft solid or viscous state that changes irreversibly into an infusible, insoluble polymer network by curing.

Curing can be induced by heat or suitable radiation, or a combination of these means. The thermoset materials are typically adhesive resins, such as melamine and epoxy resins.

The polymer materials are, for the purpose of the present invention provided in the form of fibres, fibrils, films and sheaths formed by the material, or laminated or composite structures, wherein the thermoplastic or thermosetting polymer makes up at least a part of the surface. Examples of suitable materials are thermoplastic fibres, fibrils, films and sheaths, fabrics and gauzes made by one or several of these materials, substrates of fibres, fibrils, films and sheaths having a surface provided by a thermoset resin, such as paper or cardboard webs or sheaths coated with a layer of a polymeric adhesive, to mention a few.

The present invention can be used for modifying the surfaces of synthetic polymers of the above kind, in particular for reducing the hydrophobic character thereof, for rendering the surfaces more hydrophilic or for generally improving the compatibility of the surface with objects which per se have surface properties which are different from those of the polymer.

The activation of the surface is carried out by contacting the surface of the product with a physical means for modifying the surface energy of the material. The treatment can comprise for example corona treatment, ozone treatment, laser treatment, or a combination of any of these procedures with radiation, such as electromagnetic radiation for example in the UV range. The treatment is "surface-specific" (or "non-grading"), which means that the bulk of the material is maintained unaltered and the surface bonds are essentially not broken up, preferably not to the degree which is achieved by conventional plasma treatment.

Figure 1 shows schematically an assembly wherein ozone gas is generated in an ozone generator 1 and conducted via a suitable conduit 2 to a reaction zone 3, comprising a reaction chamber into which the treated sample 4 can be placed. Typically, the reaction chamber 3 allows for a gas flow through the reaction zone, such that the activation treatment can be effected by continuous processing. In the embodiment shown in the drawing, the gas effluent is withdrawn through conduit 5 and separately recovered or passed into the ambient.

"Corona treatment" is used in the present invention synonymously with, for example, the expression "subjecting" the surface "to a corona discharge". It is a typical treatment for increasing the surface energy of the surface.

Corona discharge is a technology well-known in the art and typically applied in paper or cardboard making to a coating polyolefin film to improve adhesion between the film and the paper or cardboard web or to pre-treat an adhesive layer applied to the surface of the paper or cardboard.

Typically, the surface energy is increased by at least 20 %, preferably by about 30 %, in particular by at least 35 % up to about 100 %, calculated from the surface energy of the untreated surface (expressed in mN/m). For example, in one example using a specific polypropylene film it was possible to increase the surface charge of the film from about 33 mN/m up to 45 nM/m or more by a corona treatment.

Similar increases of the surface charge of hydrophobic surfaces of the above kind are possible by contacting the surface with ozone in gaseous form either at reduced pressure (low pressure, vacuum) or at ambient or increased pressure with an ozone-enriched gas. There are a number of ozone generators available on the market. These have been developed for treatment of water and for bleaching of fibres. A further activation treatment comprises the use of electromagnetic radiation, e.g. radiation in the range of UV radiation.

Any of the above treatments can be made more efficient by combination with one or several of the other treatments. In particular, corona or ozone treatment can be combined with radiation in the UV range.

A further physical treatment that can be used is laser radiation which can be efficient for activating the surface spotwise. However, it is generally preferred to carry out the activation by non-specific energy application ("non-specific" standing for treatment which covers a broad area). By non-specifically activating the object surface it is possible to obtain a uniform modification when the activated surface is subjected to the chemo- enzymatic treatment.

The physical activation stage is carried out at a temperature in the range from about -20 to +120 ⁰ C, preferably about 0 to 100 ⁰ C, depending on the object material. Naturally, it is preferred to operate below the glass transition point or melting point of the material. The pressure can vary in the range from about 1 mbar to 25 bar abs pressure.

In chemo-enzymatic stage of the present process, the activated material is contacted with a modifying chemical and with an enzyme capable of activating the modifying chemical. The material can be contacted simultaneously with the modifying chemical and the enzyme or the contacting can take place sequentially, first with one and then with the other agent.

In both alternatives, however, the physical activation stage is first carried out and the modifying step is performed at a second, subsequent stage.

One particular suitable way of proceeding is to apply the modifying chemical for example dispersed or - in particular - dissolved in a liquid phase onto the activated surface and simultaneously or subsequently supply the enzymatic component for example dissolved or dispersed in a liquid medium. The same liquid medium, for example water or an aqueous solution, can be used for applying both the modifying chemical and the enzyme. The modifying chemical is preferably a phenolic compound. "Phenolic compound" stands for a compounds comprising a phenol unit or a phenoxy unit or any other similar structure wherein there is an oxygen residue directly linked to a aromatic ring, optionally an aromatic ring having even heteroatoms. Conventionally, the phenolic compound includes hydroxyl, carboxy or carbonyl groups attached to a phenyl residue. "Phenyl residue" covers not only the phenyl radical by also similar fused 2 to 5 rings structures (such as naphthyl, phenanthrenyl and antracenyl). In the phenolic compound there can be several oxo atoms for example in the form of at least two of the groups of hydroxyl, carboxy and carbonyl.

Thus, generally, the phenolic compound can be defined as is a compound having 1, or 2 to 5 fused phenylic units, to which at least one oxo group is bonded.

According to one embodiment, the modifying compound is a bifunctional compound containing at least one first functional portion or group and at least one second functional group, the second functional group being selected from the group of hydroxyl (including phenolic hydroxy groups), carboxy, anhydride, aldehyde, ketone, amino, amine, amide, imine, imidine and derivatives and salts thereof.

According to another embodiment, the modifying compound is a bifunctional compound containing at least one first functional portion or group and at least one second functional group, the first functional group being selected from the group of hydroxy, carboxy, anhydride, aldehyde, ketone, amino, amine, amide, imine, imidine and derivatives and salts thereof.

According to a third embodiment, which optionally can be combined with any of the above, the phenolic compound can contain one or more substitutents, in particular aliphatic substituents, such as C ₁ -K) alkyl- or alkylene chains which can be linear or branched may exhibit 0 to 5 functional groups. These functional groups can be selected from the group of, for example, carboxy and hydroxyl groups, halogens, sulphono, sulphoxy and nitro groups.

Specific examples of phenolic compounds include ferulic acid, caffeic acid, vanilic, acid, gallic acid, hydroxytyrosol and oleuropein and derivatives thereof. The derivatives of the phenolic compounds may also comprise substituted compounds, wherein there is one or several hydrocarbon residues, such as Ci_24 hydrocarbyl radicals which can be linear or branched and optionally substituted with functional groups selected from carbonyl, aldehyde, hydroxyl, carboxyl, anhydride, nitro, amide, imide, and halogen. The derivatives can also comprise esters and ethers of the phenolic compounds, e.g. ester or ethers formed by the phenolic compounds with alcohols, diols, polyols, as well as synthetic and natural polymers, including polysaccharides and other carbohydrates such as pectins and hemicelluloses,. Examples of particularly preferred esterifying components include hydroxyl-terminated polymers, such as polyethers (e.g. poly(ethylene glycol), poly(tetrahydrofuran)) and native starch and starch derivatives.

The enzyme is used for oxidating the phenolic modifying chemical for achieving grafting of the modifying chemical onto the activated surface. Depending on the enzyme, it may be necessary additionally to provide an oxidizing component. The grafting takes place by radical-radical-coupling, as will appear from the examples discussed in more detail below.

Typically, the enzyme is an oxidative enzyme. The enzymatic part of the chemo-enzymatic reaction is preferably carried out by contacting the modifying chemical in the presence of the activated surface with an oxidizing agent, which is capable - in the presence of the enzyme - of oxidizing the phenolic or similar structural groups of the modifying chemical to provide an oxidized modifying chemical which will graft onto the activated surface.

Such oxidizing agents are selected from the group of oxygen and oxygen-containing gases, such as air, and hydrogen peroxide. Oxygen can be supplied by various means, such as efficient mixing, foaming, gases enriched with oxygen or oxygen supplied by enzymatic or chemical means, such as peroxides to the solution. Peroxides can be added or produced in situ.

According to an embodiment of the invention, the oxidative enzymes capable of catalyzing oxidation of the phenolic chemicals, are selected from, e.g. the group of phenoloxidases (E. C.1.10.3.2 benzenediol: oxygen oxidoreductase) and catalyzing the oxidation of o and p substituted phenolic hydroxyl and amino/amine groups in monomeric and polymeric aromatic compounds. The oxidative reaction leads to the formation of phenoxy radicals. Another groups of enzymes comprise the peroxidases and other oxidases. "Peroxidases" are enzymes, which catalyze oxidative reaction using hydrogen peroxide as their electron acceptor, whereas "oxidases" are enzymes, which catalyze oxidative reactions using molecular oxygen as their electron acceptor.

In the method of the present invention, the enzyme used may be for example laccase, tyrosinase, peroxidase or oxidase, in particular, the enzyme is selected from the group of lac- cases (EC 1.10.3.2), catechol oxidases (EC 1.10.3.1), tyrosinases (EC 1.14.18.1), bilirubin oxidases (EC 1.3.3.5), horseradish peroxidase (EC 1.11.1.7), manganase peroxidase (EC 1.11.1.13) and lignin peroxidase (EC 1.11.1.14).

The amount of the enzyme is selected depending on the activity of the individual enzyme and the desired effect on the phenolic compound. Advantageously, the enzyme is employed in an amount of 0.0001 to 10 mg protein/g of dry matter fiber.

Different dosages can be used, but advantageously a dosage of about 1 to 200,000 nkat/g, more advantageously 10-1000 nkat/g, the dosage being calculated from the mass of the treated substrate.

The activation treatment is carried out in a liquid medium, preferably in an aqueous medium, such as in water or an aqueous solution, at a temperature in the range of 5 to 100 ⁰ C, typically about 10 to 85 ⁰ C. Normally, a temperature of 20-80 ⁰ C is preferred. The pH of the medium is preferably neutral or slightly acidic, in particular the pH is about 2 to 10 in the case of phenoloxidases. Peroxidases are typically employed at pH of about 3 to 12.

As mentioned above, one interesting way of applying the phenolic modifying chemical is by spraying. Thus, in that embodiment the present technology comprises the steps of

- first increasing the surface energy of the surface to provide an activated surface, and, in a second subsequent step,

- applying by spraying on a discrete part of the activated surface a phenolic modifying chemical and an enzyme for bonding of the phenolic chemical to the activated surface. The spraying can be carried out by a method in which the chemical is a conveyed in the form of drops or droplets onto the activated surface. An example of such a method is the ink-jet method, which will be discussed below.

Other similar methods which will give a similar result to spraying are roll-on-roll application and flexo -printing as well as other application methods which allow for the transportation of chemicals only onto discrete areas of a surface.

As known in the art, inkjet is a non-contact digital printing method meaning that the print- head and substrate are not in contact with each other during printing. This enables that all kinds of substrates can be used for printing i.e. rigid and flexible as well as smooth and uneven substrates. Suitable substrates are for example paper, carton, board, glass, fabric, plastic and wood. The principle of inkjet printing is to transfer separate ink drops through small nozzles to a defined place on a printing substrate. Ink dots form a matrix on the printing substrate.

Success of inkjet printing process and inkjet print quality depend on ink, substrate and print-head as well as interactions between these three elements. Especially interactions between ink and substrate have a great effect. All of the elements mentioned above must be taken into account when developing inkjet systems.

The main components of an inkjet ink are the colorant or other substance to be applied on the printing substrate and the carrier phase. InkJet ink colorants are either pigments or dyes.

In the present invention, the inkjet is used as dispensing equipment for many types of substances such as biomolecules, reactive components etc. The carrier phase contains solvents and additives. According to one embodiment, the inkjet ink composition comprises 60-90 wt-% of a main solvent, 5-30 wt-% of an optional co-solvent, 1-10 wt-% of a colorant/active substance as well as optionally 0.1-10 wt-% of different additives, such as surface active agents, biocides, buffer agents, chelating agents and anti-foaming agents.

Preferably, an inkjet ink of the present kind, exhibits a low viscosity in the range of about 1-30 cP, a low surface tension of around 30 mN/m +/- 20 % and a neutral pH (in particular about 6 to 8, preferably about 6.5 to 7.5, in particular about 6.8 to 7.2). Typically, the application aims at providing providing a two-dimensional pattern on the surface, having a smallest dimension of less than 0.5 mm.

By this embodiment, the desired functionality can be imparted on the surface at only the desired, discrete areas and the functionality can take the shape of any desired form or shape on the surface. This will reduce consumption of phenolic chemical and of the enzyme.

According to one embodiment, the phenolic modifying chemical and the enzyme for bonding of the phenolic chemical to the activated surface are applied in a plurality of patterns having smallest dimensions of less than 0.5 mm.

In the above embodiment, the enzyme and the phenolic modifying chemical can be jointly applied on the surface, or they can be applied on the surface in sequence.

The bonding of the modifying agent to the surface is firm. It takes place by radical-radical coupling which may lead to covalent bonding, although the exact nature of the chemical bond is difficult to ascertain from the product. It has, however, been found that the modifying chemical is bonded to the surface to such an extent that it cannot essentially be removed by washing the modified object in water or in another aqueous medium.

Typically, less than 20 % by weight, in particular less than 10 % by weight and preferably less than about 5 % by weight of the modifying agent will be removed after repeated (2 to 5 time) rinsing of the object in water.

As mentioned above, the present invention also achieves new products or objects having a modified surface. The objects are formed by synthetic polymers and being provided in the form of, e.g. fibres, fibrils, films and sheaths formed by the thermoplastic or thermosetting polymer material, or laminated or composite structures, wherein the thermoplastic or thermosetting polymer makes up at least a part of the surface. The objects are characterized by having a phenolic modifying agent directly bonded to the surface for modifying the surface properties thereof. The improved surface properties are in particular selected from wetting, antistatic, soil repellent, adherence, and antimicrobial properties. The spraying application can be used for producing printed electronics or conductive areas and for diagnostic purposes. In the latter case, by spraying it is possible also to immobilize diagnostic reagents on the surface of an inert polymeric substrate (for example polystyrene). Applications in microfluidistics and in technologies employing microarrays are conceivable.

Naturally, the spraying by, e.g., inkjet technology makes it possible to produce on laboratory scale modified surfaces capable of being used in research.

The following non- limiting examples illustrate the invention:

Example 1

Production and purification of the enzyme Laccase

The Trametes hirsuta laccase was purified as follows.

The culture filtrate from T. hirsuta strain VTT D-443 was concentrated by ultrafiltration (PCI, 25-kDA cut off). Salts were removed from the concentrate and the buffer changed to 15 mM acetate buffer pH 5.0 by gel filtration (Sephadex G 25; h=57 cm, V=18 1). The active fractions were pooled and the solution was concentrated again by ultrafiltration (PCI, 25-kDa cut off). The sample was applied to a DEAE Sepharose Fast Flow anion exchange column (h= 29 cm, V= 9 1), which was equilibrated with 15 mM sodium acetate pH 5.0. Proteins were eluted with a linear 0-200 mM NaCl gradient. Laccase eluted at 120-150 mM NaCl concentration. Positive fractions were pooled and Na ₂ SO ₄ was added to the sample to final concentration of IM. The sample was applied to a Phenyl Sepharose Fast Flow hydrophobic interaction column (h = 20 cm, V = 400 ml) equilibrated with 20 mM citrate buffer pH 5.0 containing 1 M. Proteins were eluted with a linear decreasing Na ₂ SO ₄ gradient (1000-0 mM) Na ₂ SO ₄ . Laccase eluted at 20 mM Na ₂ SO ₄ salt concentration. The purest fractions were pooled and concentrated (Millipore; PMlO membrane). All chromatographic resins were supplied by Pharmacia. Example 2

Surface activation by ozone, corona and UV

For ozonation the experimental setup for activation consisted of an exsiccator and an ozonizer, from which the ozone was conducted to chamber via plastic tube. Another tube from the chamber conducted to air removal of fume cupboard. The setup is shown in Figure 1. The ozone concentration level was approximately 450 ppm.

Surface activation of different film materials were verified by contact angle measurements. Decrease in contact angle indicated activation. Table 1 shows the effect of ozone on the contact angle values of different film materials.

Table 1 Contact angle values of different film materials before and after fifteen minutes ozone treatment

Corona treatments were carried out using semi-industrial roll-to-roll system (Vetaphone ET 1 Treater) with velocities from 4,5 m/min up to 120 m/min. Table 2 shows how corona treatment decreased the contact angle values of different film materials.

Table 2 Effect of corona treatment with wattage of 0,8kW on contact angle values of different films.

UV-irradiation: Exfo OmniCure 2000S UV and Original HANAU Fluotest devices were used in UV-activation treatments. UV-irradiation was not as effective as ozone and corona, but contact angle values decreased to some extent as can be seen in Table 3. UV-radiation was used also in combination with ozone to intensify the treatment. Table 3 Effect of 2 hours UV-irradiation on contact angle values of different films

Example 3

Functionalisation of PP film with FA

Surface activation of PP film (BorcleanTM HC318BF) samples was carried out exposing samples (3x3 cm) to ozone for 30 minutes. The treatment set-up is described in Example 2.

Chemo-enzymatic treatment: A bonding chemical (FA 0.1 mmol/g) was dissolved in 0.025M sodium-succinate buffer of a pH value of 4.5. After that, they were immersed into the treatment solution at room temperature for 240 minutes, stirring every now and then. Immediately after the sample had been immersed into the solution, Trametes hirsuta laccase (ThL) was added at a dosage of 100 nkat/g. Laccase was added to initiate the radicalization reactions of the bonding chemical. After the chemo-enzymatic treatment samples were rinsed using deionized water. The samples were washed for an hour using magnetic stirrer, and then rinsed again before drying. New surface functionality was confirmed using contact angle measurements. Reference samples in which either laccase or bonding chemical, or both were absent, were included. The effect of the treatments on the contact angle of the PP film is shown in Table 4.

Table 4 Contact angle of PP film after treatments with ozone, laccase and FA

Sample PP, raw PP + O ₃ PP + O ₃ + PP + O ₃ + PP+ O ₃ +

ThL FA ThL + FA

Contact 104 90 89 98 73 angle [°] According to contact angle results, FA did not bind to the surface without laccase activation. Contact angle decreased substantially only when both laccase and bonding chemical were involved in the treatment.

Example 4

Functionalisation of PP non-woven with FA

A similar functionalisation treatment as described in Example 3 was carried out using PP non- woven (Suominen Kuitukankaat Oy, no spinning additives, square mass of 45 g/m ² ) as sample material. In addition to non- woven, also film samples made of PP were included in this experiment. The concentration of the bonding chemical was 0.2 g/L and laccase (ThL) was dosed at 2575 nkat/g(FA) into the treatment solutions.

Dye adsorption tests in which Toluidine Blue O was used as an indicative dye were carried out to verify the new functional groups on surface. Dyeing assay was based on linking tendency of positively charged colour molecules to negatively charged carboxyl groups in basic conditions. Amount of attached dye was determined at 633 nm. Results are shown in Table 5.

Table 5 Adsoption of Toluidine blue O to surfaces of PP film and non-woven after treatments with ozone, laccase and ferulic acid

The dye assay confirmed the presence of new functional groups on the surfaces of PP film and non- woven. The amount of dye adsorption was doubled when ozonized surface was processed with laccase and ferulic acid. Example 5

Functionalisation of PP film with FA derivatives

FA derivatives FA-PEG and FA-starch were synthesized at VTT by an esterifϊcation mechanism. Linear low-molecular- weight polysaccharide maltodextrin 20 (with twenty glucose units) was used in the synthesis of FA-starch. Poly(ethylene glycol) (-O-CH2-CH2) with a molecular weight of 200 g/mol was used in the synthesis of FA-PEG. Functionalisation treatment of PP film was carried out like in Example 3. FA-PEG dosage of 0,1 mmol/g, laccase (ThL) dosage of 100 nkat/g and ozonation time of 180 minutes were used. The effect of the treatments on contact angle of PP film is shown in Table 6.

Table 6 Contact angle of PP film after treatments with ozone, laccase and FA-PEG

Sample PP, raw PP + O ₃ PP + O ₃ + PP + O ₃ + PP+O ₃ + ThL

ThL FA-PEG + FA-PEG

Contact 104 99 95 99 58 angle [°]

In the treatment with FA-starch, dosage was 0.01 mmol/g, laccase (ThL) dosage was 50 nkat/g, and reaction times of both the ozonation and the chemo-enzymatic reaction were 30 minutes.

The effect of the treatments on the contact angle of the PP film is shown in Table 7.

Table 7 Contact angle of PP film after treatments with ozone, laccase and FA-starch

When FA-PEG and FA-starch were used as bonding chemicals in the functionalisation treatments of PP film, the same trend as in example 3 was observed; Contact angle decreased substantially only when laccase activation of bonding chemical was used, as shown in tables 2 and 3. With FA derivatives the effect was more significant and lower contact angle values were achieved than with pure FA.

Example 6 Analysis of the film surface

Behaviour of water on film surface changed evidently due to functionalisation treatments, as shown in Figure 2; the figure shows water on untreated (Fig. 2a) and on FA-starch functionalized (Fig. 2b) PP film samples.

Water dropped on the surface of an untreated film was easily rolled off the surface. By contrast, on the surface of a PP film containing FA-starch functionalities water unfurled evenly over the whole sample surface. Surface analysis by AFM showed that the FA-starch layer was uniform and covered the film surface throughout.

Changes in surface chemical composition were determined using ESCA technique. In the ESCA analysis was detected an increase in oxygen content on the functionalized surfaces, which indicated that the bonding chemical FA-PEG was present on the surface. The results are shown in Table 8:

Table 8 Chemical composition of PP film surface as atomic percent

Example 7

Functionalisation of PET film with FA and its derivatives

Similar functionalisation treatments as described in Examples 3 and 5 were carried out using a PET film (Equipolymers, no antioxidants) as sample material. The same FA dosage was used as earlier with laccase dosage of 100nkat/g. Ozonation time was 20 minutes. Meaured contact angle values are shown in Table 9.

Table 9. Contact angle of PET film after treatments with ozone, laccase and FA

With FA-PEG a laccase dosage of 500 nkat/g was used. The effect of the treatment on the film surface as contact angle is shown in Table 10.

Table 10. Contact angle of PET film after treatments with ozone, laccase and FA- PEG

The treatment with FA-starch was conducted exactly as described in Example 5 with the PP film, except that the reaction time of the chemo -enzymatic reaction was 180 minutes. The result of the determination of contact angles is shown in Table 11.

Table 11. Contact angle of PET film after treatments with ozone, laccase and FA- starch

The contact angle results showed the same trend as with PP film in Examples 3 and 5; functionalisation treatments with FA and its derivatives turned film surface more hydrophilic.

Example 8

Functionalisation of PLA film with FA and its derivatives

An PLA film was used as sample material in similar functionalisation treatments as described in Examples 3, 5 and 6. In the treatment with FA laccase, the dosage was 500 nkat/g and the treatment solution was sprayed on sample surface. The effect of the treatment on the contact angle is shown in Table 12.

Table 12. Contact angle of PLA film after treatments with ozone, laccase and FA

Laccase dosages of 100 nkat/g were used with FA-PEG. The effects of the treatment to film surface on the contact angle is shown in Table 13.

Table 13. Contact angle of PLA film after treatments with ozone, laccase and FA- PEG

Again the same phenomenon was proven as with PP and PET films (in Examples 3, 5 and 6) - the contact angle values decreased as the film surface turned more hydrophilic due to the functionalisation treatments. Example 9

Enzyme- aided functionalisation of polypropylene by ink jet printing

Surface activation of polypropylene (PP) and oriented polypropylene films (OPP) was carried out by exposing samples to corona treatment (Vetaphone) at a power of 100 Wm ² /min prior to enzymatic treatment.

Enzymatic treatment was carried out as follows: three ink solutions were prepared, one containing vanillic acid-PEG, one FA-starch and one Trametes hirsuta laccase. The ink compositions are shown in Table 14. The inks were filtered and let to stand for one day before printing. Directly after surface activation first the bonding chemical ink was printed, and soon after that, the laccase ink. The printing conditions are shown in Table 15. After one hour from the printing, samples were rinsed with deionized water, washed for an hour with magnetic stirrer and then rinsed again before drying. New surface functionality was confirmed using contact angle measurements. Reference samples, printed only with base ink or with only bonding chemical or laccase containing inks, were included. The effect of the treatments on the contact angle of PP and OPP films is shown in Tables 16 and 17.

Table 14 Ink composition and dosages

Chemical Dosage

Ink composition Polyvinylpyrrolidone (PVP 15) l-2g 1,3 propandiol 8ml Dynol 0.05 % 25mM Na-succinic buffer (pH 4,5) 40ml

A Bonding chemical 1 FA-starch 0.68 mg/ml

B Bonding chemical 2 Vanillic acid-PEG lOO mg/ml

C Laccase Trametes hirsuta 800nkat/ml

Table 15 Printing conditions

Ink-jet printer FUJIFILM Dimatix DMP-2831

Print resolution 1270 dpi

Nozzle voltage variable voltages optimized for ink

Drop size 10 pi

Printhead temperature RT

Firing frequency 5 kHz

Table 17 Contact angle of OPP film after corona treatment and in jet printing

Sample OPP, raw OPP + corona OPP + ink OPP + FA- starch +

ThL

Contact angle [ ^c 81 81 81 64

According to contact angle results, the bonding chemicals did not bind to the surface without laccase activation of the bonding chemical. Contact angle decreased substantially only when both laccase and bonding chemical were involved in the treatment.