Efficient process for converting food industry waste into quality bioplastic film

Abstract

The present invention relates to an efficient process aimed at recycling material from the food industry, preferably from the fish industry, such as, for example, that extracted from fish skin, so as to realise a general, at least partially circular and sustainable process concerning consumer goods comprising a bioplastic film.

Description

[0001] EFFICIENT PROCESS FOR CONVERTING FOOD INDUSTRY WASTE INTO QUALITY BIOPLASTIC FILM.

[0002] DESCRIPTION

[0003] Technical field

[0004] The present invention is in the field of industrial processes related to recycling materials, in particular food industry waste, preferably from the fish industry, as well as in the field of biofilms, viz., bioplastic films.

[0005] State of the art

[0006] In today’s modem world, the need is greatly felt for sustainable industrial processes and materials, viz., those which give rise to a minimal impact on the environment and the resources around us. In order to promote and steer the existing processes and technologies towards sustainability and respect for the environment and, in particular, towards eco-sustainability, according to the recent principles of ESG (Environmental, Social, Governance), nowadays there is much talk of sustainability and the circular economy, viz., configuring processes so that, with their circularity, they have no impact or a more limited impact on the environment and the resources drawn therefrom with respect to the past.

[0007] The concept of circular economy becomes particularly important when it relates to industrial technologies concerning the production of materials which are in the first instance non-recyclable, such as those generated by the traditional polymerisation processes underlying the production of plastics, e.g., polyethylene, polypropylene, nylon, polyethylterephthalate, etc. The result of such productions are plastics which are difficult to recycle, on the one hand, and on the other products made from petroleum derivatives and thus withdrawing a resource which can no longer be replaced.

[0008] Therefore, today there is a desire to prepare films with the same appearance as traditional plastic films, typically used for packaging, from auto-regenerating natural resources, and capable of being substantially completely biodegradable and, moreover, preferably starting from second-rate resources such as industrial waste.

[0009] Summary of the invention

[0010] The problem addressed by the present invention is therefore to provide an efficient process for recycling waste from the food industry, particularly the fish industry, directed to the preparation of a film made with biomaterial, viz., a bioplastic film of a quality comparable to that of the plastic-based films currently used for packaging, including protective films having an oxygen barrier, sealable packaging films, heat-shrink films, upper films for MAP / ATP, various food packaging options such as dry food bags, vacuum bags, disposable packaging for cosmetics, and oils and laminated materials incorporating paper and aluminium.

[0011] Therefore, the present invention solves the aforesaid problem by means of a process for preparing a bioplastic film, through the preparation of a suitable bioplastic composition, while at the same time recycling food industry waste, preferably from the fish industry.

[0012] Further features and advantages of the present invention will result from the description of some embodiment examples, provided as an indication of the invention itself.

[0013] Description of the figures

[0014] Figure 1 illustrates the creation of a quality bioplastic film by means of the process of the present invention.

[0015] Figure 2 illustrates the bioplastic film of the invention in the peeling step, viz., the step in which the film is separated from the support on which it was generated.

[0016] Figure 3 illustrates the bioplastic film of the invention in the step in which it is rolled onto a rigid cardboard support.

[0017] Figure 4 illustrates the film of the invention.

[0018] Detailed description of the invention

[0019] For the purposes of the description of the present document, the term “and / or”, when used in a list of two or more items, means that any one of the listed items may be used alone, or in any combination of two or more of the listed items.

[0020] For example, if a combination is described as containing components A, B and / or C, or, A and / or B and / or C, the composition can contain only A; only B; only C; A and B in combination; A and C in combination; B and C in combination; or A, B and C in combination.

[0021] The terms “comprises”, “comprising” or any other variation thereof are intended to cover a non-exclusive inclusion such that a process, method, use, etc. which comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent in such a process, method, use, etc. An element followed by “comprises a...” does not preclude, without further constraints, the existence of further identical elements in the process or use comprising the element.

[0022] In order to obtain a film which is appreciated by the market, viz., a film which is capable of offering performance similar to that of commonly known plasticbased packaging films, said film must have a series of features which are simultaneously present in the film produced.

[0023] Furthermore, for production purposes, the mixing of components must lead to a composition such that it can be easily made into film.

[0024] Furthermore, for production purposes, it is therefore important to arrange a film which is easily peelable from the substrate, viz., a film which can be easily removed by peeling from the support on which it was generated, without cracking, breaking, losing pieces of film, etc.

[0025] A further aspect of the film is the need to have an absence of bubbles and particles in the film produced, homogeneity of the film, absence of bulges.

[0026] Furthermore, the film should have peel strength and poor adhesion to the support.

[0027] Bioplastic compositions with overly low viscosity cannot be used to give rise to films of bioplastic material.

[0028] Therefore, a subject matter of the present invention is a bioplastic composition for preparing bioplastic films comprising:

[0029] - from 40% to 70% (w / w) water,

[0030] - from 25% to 50% (w / w) bioplastic, where such bioplastic comprises: a) from 45% to 99.9% (w / w) gelatine of animal origin, b) from 0.1 % to 30% (w / w) of at least one cyclodextrin, with respect to the weight of the bioplastic;

[0031] - from 1 % to 15% (w / w) plasticiser,

[0032] - from 0.1 % to 5% (w / w) defoamer, with respect to the weight of the bioplastic composition.

[0033] In fact, it was surprisingly found that the aforesaid composition, combined with the process for the preparation thereof, as well as with the process for preparing a bioplastic film, enables the creation of bioplastic films having similar and comparable features to those of films made of plastic material.

[0034] In particular, the aforesaid composition has a bioplastic content, in terms of weight-on-weight percentage with respect to the total weight of the bioplastic composition, such as to ultimately provide a quality bioplastic film, viz., similar in appearance and performance to the films currently made with plastic material derived from the petroleum industry.

[0035] Furthermore, the aforesaid composition has ideal and necessary viscosity values for making bioplastic films.

[0036] Bioplastics are based on gelatine of animal origin, viz., a gelatine-based material (substantially or specifically collagen hydrolysate-based).

[0037] Preferably, said animal gelatine is selected from any of the fish gelatines commonly found in the literature and / or on the market.

[0038] Even more preferably, said gelatine is extracted from fish skin.

[0039] Preferably, the animal gelatine is selected from a commercial gelatine extracted from fish skin. Even more preferably, the gelatine is characterised by the trade name Fish Skin Gelatine GLF / F 22, from 08 mesh, produced and marketed by the Company LAPI GELATINE (Via Lucchese 158, Empoli (Fl), Italy).

[0040] Preferably, the gelatine of animal origin is gelatine from fish species.

[0041] The bioplastic comprises at least one cyclodextrin, abbreviated CD.

[0042] Cyclodextrins are characterised by a particular frustoconical structure in which a hydrophilic outer part and a hydrophobic inner cavity can be identified.

[0043] Cyclodextrins are classified based on the number of glucose units forming them, and there are three main families, indicated with the letters a-, [3- and y-, which possess, respectively, 6, 7 and 8 glucose units in their structure. When these constituent units are present in odd numbers, the solubility of these molecules decreases, resulting in molecules which are more hydrophobic with respect to the others (viz., those with an even number of glucose units).

[0044] Of the cyclodextrins mentioned above, (3-cyclodextrin (with 7 glucose units) has this feature and is therefore a particularly favoured solution to the above problem.

[0045] In a particularly favoured embodiment of the present invention, it was found to be the best cyclodextrin for the purposes of the present invention. In fact, with this cyclodextrin it was found that the material’s barrier power to water (and / or also to gases) increases significantly, to a greater extent than other cyclodextrins used in the art, while avoiding the problems created by the same. In fact, cyclodextrins do not evaporate at room temperature, are odourless and do not create a cross-linked structure. The cyclodextrin comprised in the bioplastic can preferably be selected from:

[0046] - natural CDs: viz., a-CD, |3-CD, y-CD;

[0047] - derivative and / or semi-synthetic CDs, wherein said cyclodextrins can be: alkylated CDs, branched CDs, polymeric CDs, linked CDs, etc.

[0048] Preferably, the cyclodextrin (CD) is a natural cyclodextrin selected from a commonly commercially available [3-cyclodextrin.

[0049] It was found that, among others, the plasticiser has a positive effect on the detachment of the film from the support on which it was generated.

[0050] The plasticiser can be chosen from common plasticisers such as any suitable, non-toxic, commercial plasticiser of known type, available from the catalogues of various plasticiser producers, e.g., glycerol (or glycerine); and / or water- soluble polyols, in particular selected from commercial ones, e.g., those obtainable also from renewable sources; e.g., polyethylene glycols having variable molecular weight, which allow making rigid packaging and / or polyvinyl alcohols of variable molecular weight, which allow making better performing materials; and / or suitable mixtures thereof.

[0051] Defoamer is a substance adapted to depress the formation of foam. Various defoamers which can be used for the present bioplastic composition are known and commercially available.

[0052] Optionally, the bioplastic composition can further comprise viscosity-modifying agents. Said agents can increase or decrease the viscosity of the bioplastic composition which is the subject matter herein. Viscosity modifiers are commercially available substances.

[0053] Bioplastic is solid at room temperature, in particular it is a solid powder.

[0054] Preferably, said composition further comprises:

[0055] - from 0.1 % to 2% (w / w) of cyclodextrin additive.

[0056] Preferably, said bioplastic composition comprises:

[0057] - from 45% to 60% (w / w) water,

[0058] - from 30% to 45% (w / w) bioplastic, where such bioplastic comprises: a) from 45% to 99.9% (w / w) gelatine of animal origin, b) from 0.1 % to 30% (w / w) of at least one cyclodextrin, with respect to the weight of the bioplastic;

[0059] - from 7% to 13% (w / w) plasticiser,

[0060] - from 0.2% to 0.8% (w / w) defoamer, with respect to the weight of the bioplastic composition. Even more preferably, said composition comprises:

[0061] - from 45% to 55% (w / w) water,

[0062] - from 35% to 45% (w / w) bioplastic, where such bioplastic comprises: a) from 45% to 99.9% (w / w) gelatine of animal origin, b) from 0.1 % to 30% (w / w) of at least one cyclodextrin, with respect to the weight of the bioplastic;

[0063] - from 10% to 13% (w / w) plasticiser,

[0064] - from 0.2% to 0.8% (w / w) defoamer, with respect to the weight of the bioplastic composition.

[0065] Preferably, relative to the aforesaid bioplastic composition, said bioplastic comprises: a) from 60% to 85% (w / w) gelatine of animal origin, b) from 10% to 20% (w / w) of at least one cyclodextrin, with respect to the weight of the bioplastic.

[0066] Preferably, the bioplastic composition has a viscosity comprised between 100,000 and 1 ,000,000 mm2 / s or cps, or between 150,000 and 800,000 mm2 / s or cps, or between 192,000 and 709,000 mm2 / s or cps, wherein the viscosity is measured at 25°C.

[0067] Another subject matter of the present invention is a process for preparing the bioplastic composition as described above comprising the following steps:

[0068] A) mixing water with the defoamer,

[0069] B) heating the mixture of step A) to a temperature comprised between 30°C and 50°C,

[0070] C) under stirring, slowly adding the bioplastic, wherein said bioplastic is in the form of a solid powder,

[0071] D) heating the solution to a temperature comprised between 70°C and 90°C,

[0072] E) optionally adding the additive cyclodextrin,

[0073] F) maintaining stirring at a temperature comprised between 70°C and 90°C for 30 minutes,

[0074] G) cooling down to a temperature comprised between 30°C and 50°C,

[0075] H) adding the plasticiser and stirring for 15 minutes,

[0076] I) degassing the mixture under vacuum at a residual pressure of 400 mbar.

[0077] In fact, it was found that by producing the bioplastic composition according to the aforesaid process, said bioplastic composition has a viscosity and, substantially, the absence of air bubbles, features which allow preparing quality bioplastic films.

[0078] Step B) can preferably be conducted at 40°C.

[0079] Step F) can preferably be conducted at 80°C.

[0080] Step G) can preferably be conducted at 40°C.

[0081] Step I) is conducted until the development of air bubbles disappears from the bioplastic composition.

[0082] Another subject matter of the present invention is a process for preparing a bioplastic film comprising the following steps:

[0083] A1 ) preparing the bioplastic composition as described above according to the process as described above,

[0084] B1 ) bringing the bioplastic composition to a temperature preferably comprised between 35 and 55°C,

[0085] C1 ) extruding to make a film or filming the composition of step B1 ),

[0086] D1 ) drying the film of step C1 ) with a dry air stream having a temperature comprised between 90°C and 130°C.

[0087] In fact, it was surprisingly found that the combination of various critical parameters, such as the viscosity of the bioplastic composition, its bioplastic content in terms of percentage within the bioplastic composition, the drying conditions of the film, and the qualitative and quantitative formulations of the bioplastic compositions, allows preparing a film which meets the aforesaid requirements.

[0088] In fact, one of the most significant parameters is the viscosity of the composition, which influences obtaining the desired film thickness and quality thereof. The same applies to the bioplastic content in the composition.

[0089] In fact, it has been found that, for production purposes, the bioplastic composition should result in a viscosity range between 100,000 and 1 ,000,000 mm2 / s or cps, preferably between 150,000 and 800,000 mm2 / s or cps, more preferably between 192,000 and 709,000 mm2 / s or cps, where the viscosity is measured at 25°C. In fact, it has been found that, operating in such viscosity ranges, the bioplastic composition is such as to be easily filmable.

[0090] Preferably, the bioplastic composition can further comprise a viscosity modifier. More preferably, said viscosity modifier can be present in an amount comprised between 0.1 % and 5% (w / w) with respect to the total weight of the bioplastic composition.

[0091] The drying parameters, in particular the temperature of the drying air, also proved to be important parameters for determining the features of the final film. A further important parameter is the thickness of the wet bioplastic film layer, which is comprised between 100 and 600 microns.

[0092] The thickness of the bioplastic film generated by the process by means of the bioplastic composition used is comprised between 10 and 200 microns.

[0093] Furthermore, the bioplastic film obtainable from the process by means of the bioplastic composition used is water-soluble.

[0094] This feature of the bioplastic film is important because it allows having a film which can be easily disposed of within the home using hot water.

[0095] Preferably, the procedure, and in particular step B1 ), is conducted at a temperature between 40°C and 50°C.

[0096] Step C1 ) can be carried out in various manners; preferably, the bioplastic composition is filmed. The bioplastic composition can be filmed, preferably, by means of a foil.

[0097] Preferably, the process, as referred to in step D1 ), is carried out with a dry air stream having a temperature comprised between 105°C and 125°C.

[0098] The aforesaid process for preparing a bioplastic film is industrially feasible by means of devices now known to the person skilled in the art, related to any traditional film production process using traditional plastic processing techniques such as, for example, solvent evaporation moulding (casting), blow moulding, extrusion, lamination, compression moulding, injection moulding, rotomoulding and thermoforming; preferably, casting and / or lamination. Consequently, there is no need to illustrate in detail any of these well-known processes for the production of plastic films, which are well known to the person skilled in the art.

[0099] Another subject matter of the present invention is the use of the bioplastic composition as described above for preparing bioplastic films.

[0100] In particular, the use of the bioplastic composition for preparing bioplastic films for packaging is preferred.

[0101] Another subject matter of the present invention is the thermoplastic material obtainable according to the process described above.

[0102] Furthermore, in particular, the use of the bioplastic composition is preferred for preparing a bioplastic film having an oxygen barrier range comprised between 0 and 3 cc / (m2 24h) 55% relative humidity and temperature of 23°C.

[0103] Furthermore, the use of the bioplastic composition for preparing a bioplastic film having a smooth, shiny surface and a rough surface resulting from the peeling process is also preferred.

[0104] Furthermore, the use of the bioplastic composition for preparing a water- soluble bioplastic film is also preferred.

[0105] Further, the use of bioplastics for making bioplastic films for packaging is preferred, including protective films having an oxygen barrier, sealable packaging films, heat-shrink films, upper films for MAP / ATP, various food packaging options such as dry food bags, vacuum bags, disposable packaging for cosmetics, and oils and laminated materials incorporating paper and aluminium.

Claims

CLAIMS1 ) Bioplastic composition for preparing bioplastic films comprising:- from 40% to 70% (w / w) water,- from 25% to 50% (w / w) bioplastic, where such bioplastic comprises: a) from 45% to 99.9% (w / w) gelatine of animal origin, b) from 0.1 % to 30% (w / w) of at least one cyclodextrin, with respect to the weight of the bioplastic;- from 1 % to 15% (w / w) plasticiser,- from 0.1 % to 5% (w / w) defoamer, with respect to the weight of the bioplastic composition.2) Composition according to claim 1 , further comprising:- from 0.1 % to 2% (w / w) cyclodextrin additive.3) Composition according to any one of claims 1 to 2, wherein said composition comprises:- from 45% to 60% (w / w) water,- from 30% to 45% (w / w) bioplastic, where such bioplastic comprises: a) from 45% to 99.9% (w / w) gelatine of animal origin, b) from 0.1 % to 30% (w / w) of at least one cyclodextrin, with respect to the weight of the bioplastic;- from 7% to 13% (w / w) plasticiser,- from 0.2% to 0.8% (w / w) defoamer, with respect to the weight of the bioplastic composition.4) Composition according to any one of claims 1 to 3, wherein said composition comprises:- from 45% to 55% (w / w) water,- from 35% to 45% (w / w) bioplastic, where said bioplastic comprises: a) from 45% to 99.9% (w / w) gelatine of animal origin, b) from 0.1 % to 30% (w / w) of at least one cyclodextrin, with respect to the weight of the bioplastic;- from 10% to 13% (w / w) plasticiser,- from 0.2% to 0.8% (w / w) defoamer, with respect to the weight of the bioplastic composition.5) Composition according to any one of claims 1 to 4, wherein said bioplastic comprises: a) from 60% to 85% (w / w) gelatine of animal origin,b) from 10% to 20% (w / w) of at least one cyclodextrin, with respect to the weight of the bioplastic.6) Composition according to any one of claims 1 to 5, wherein said composition has a viscosity comprised between 100,000 and 1 ,000,000 mm2 / s or cps, or between 150,000 and 800,000 mm2 / s or cps, or between 192,000 and 709,000 mm2 / s or cps, wherein the viscosity is measured at 25°C.7) Process for preparing the bioplastic composition according to any one of claims 1 to 6 comprising the following steps:A) mixing water with the defoamer,B) heating the mixture of step A) to a temperature comprised between 30°C and 50°C,C) under stirring, slowly adding the bioplastic, wherein the bioplastic is in the form of a solid powder,D) heating the solution to a temperature comprised between 70°C and 90°C,E) optionally adding the additive cyclodextrin,F) maintaining stirring at a temperature comprised between 70°C and 90°C for 30 minutes,G) cooling down to a temperature comprised between 30°C and 50°C,H) adding the plasticiser and stirring for 15 minutes,I) degassing the mixture under vacuum at a residual pressure of 400 mbar.8) Process for preparing a bioplastic film comprising the following steps: A1 ) preparing the bioplastic composition of any one of claims 1 to 6 according to the process of claim 7,B1 ) bringing the bioplastic composition to a temperature comprised between 35°C and 55°C,C1 ) extruding to make a film or filming the composition of step B1 ),D1 ) drying the film of step C1 ) with a dry air stream having a temperature comprised between 90°C and 130°C.9) Process according to claim 8, wherein step D1 ) is carried out with a dry air stream having a temperature comprised between 105°C and 125°C.10) Use of the bioplastic composition according to any one of claims 1 to 6 for preparing bioplastic films, or bioplastic films having an oxygen barrier range comprised between 0 and 3 cc / (m2 24h) 55% relative humidity and a temperature of 23°C, or bioplastic films having a smooth, shiny surface and a rough surface resulting from the peeling process, or water-soluble bioplasticfilms.11 ) Thermoplastic material obtainable according to the process of any one of claims 1 to 10.

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