The object of the invention is a biodegradable thermoplastic polymer composition based on starch reinforced with natural cellulose fillers and methods for its manufacture, applicable to the production of disposable and reusable products or packaging materials in particular for food contact.

Polish patent Pat.216930 discloses a method for manufacturing thermoplastic starch for disposable packaging by mixing corn starch in the amount of 50-80 parts by weight with plasticizer in the form of glycerin in the amount of 20-50 parts by weight, heating the mixture obtained in this way to a temperature of 60-100°C and draining the water. The premix is conditioned for 24 h, then plasticized by shear forces at 130-150°C, extruded in the temperature range of 150-180°C, and granulated.

Polish patent application no. P.433862 discloses a method of manufacturing thermoplastic starch for industrial applications in the production of utility products by injection molding and blow molding. The method consists in mixing starch, with at least one plasticizer from the group including citric acid, water, glycerol, sorbitol for a time covering the range from 1 to 9 h at 60-120°C, with the content of citric acid in the mixture being at most 5 wt.%. The applied ratio of starch to plasticizer varies between 2:1 and 20:1. The method sequentially involves extrusion of the pre-mix directly after mixing (in the temperature range of 130-150°C) without conditioning, cooling of the extrudate and optional granulation. The inconvenience of this method is the use of citric acid to obtain thermoplastic starch, which causes esterification and crosslinking of starch, thus increasing the brittleness of the resulting product. In addition, the use of citric acid in a preferably variant of the invention significantly limits the possibility of using the thermoplastic starch obtained in this way to form its compositions with other biopolymers, since citric acid decomposes at a temperature of about 175°C, which is below the processing temperature of most compostable polyesters such as PLA (polylactide), for example, or PBAT (polybutylene adipate terephthalate). This decomposition probably manifests itself as outgassing and mechanical weakening of injection moldings or extrusions after the extrusion process. An inconvenience in the method according to the invention is also the requirement to mix native starch with the plasticizer at temperatures above 60°C, which can cause an uncontrolled reaction of starch cross-linking by citric acid (multi-carboxylic acid) through polycondensation, consequently making it more difficult to process by increasing melt flow rates and causing difficulties in the possible recycling of usable products made with it.

Polish Patent Description Pat.207301 discloses a method of manufacturing a biodegradable polymer material based on renewable raw materials for disposable packaging. Thermoplastic starch granulate is obtained by mixing (heat-dynamic treatment) starch with a plasticizer from the polyol group: glycerin, esters, preferably citric acid esters, glycol, as well as water at an ascending temperature from 40 to 170°C. It is then subjected to shear and pressure at 120-190°C, carried out into a melt, extruded and granulated. Starch granulate is mixed, with at least two thermoplastic polymers, preferably ethylene-acrylic acid copolymer or polyethylene grafted with maleic anhydride (at the temperature at which they form a melt), extruded and subjected to granulation. Processing auxiliaries are also used: lubricants - favorably from 0.05 to 0.25% of oleamide, from 0.1 to 0.5% of magnesium, zinc and calcium stearate, from 0.1 to 0.15% of tri-alkolphenols.

Polish patent Pat.214329 discloses a method of obtaining a biodegradable polymer material based on thermoplastic starch and polylactide, preferably amorphous polylactide. In the first stage, the starch, preferably potato or corn starch, is mixed with glycerin and the plasticization process is carried out in an extruder. The finished melt is extruded at 130-150°C. The polylactide is mixed with maleic anhydride and a free radical initiator in an extruder and extruded at 100-140°C. The starch granulate is then mixed with PLA granulate and PLA granulate grafted with maleic anhydride in a 1 :1 ratio, containing PLA grafted with maleic anhydride at 60% of the mixture (or 40 parts by weight of modified starch and 55 or 57.5 parts by weight of the PLA mixture with 5 or 2.5 parts by weight of auxiliaries to improve the compatibility, such as gluten), and carries out the extrusion process at 80-150°C.

European patent application EP 2467418A1 describes a method for obtaining a blend of thermoplastic starch with synthetic polymers. In the first stage, dry starch, e.g. corn, potato, rice or wheat, is introduced into a twin screw extruder and, in turn, a plasticizer in the form of a polyol: glycerol, sorbitol, polyethylene glycol, their mixture or, for example, urea, formamide. Preferably, the plasticizer is glycerol and/or sorbitol in an amount of 5 to 40% by weight. The extrusion process leads to obtaining TPS thermoplastic starch. A polymer is then introduced in dry form, such as a pellet of a substance from a group including polyethylene, polypropylene, polylactide, polycaprolactone, polybutylene succinate, or mixtures thereof, to produce the right blend. The ratio of starch to synthetic polymer is preferably between 10 and 90%. In addition, in order for the polymer to show greater compatibility, it is possible to introduce compatibilizers, preferably unsaturated carboxylic acid anhydrides.

From Chinese patent application CN 104312482 A is known how to obtain a biodegradable material for use as a hot glue using thermoplastic starch and gum rosin. In the first stage, thermoplastic starch is blended at high speed with a plasticizer such as ethylene glycol at a ratio of 1 :0.2-0.5 for 10-30 minutes at a mixing speed of 2000 to 4000 rpm and conditioned for 24 hours. In the next stage, the mixture is heated to 120- 140°C, cooled and granulated to obtain thermoplastic starch. Gum rosin is heated under a nitrogen atmosphere to 150-200°C, gradually mixed with polyol, catalyst and antioxidant, then subjected to reaction at 240-280°C for 5-10 hours and mixed with thermoplastic starch for 20-30 minutes, and cooled in the final stage. Among other things, solid paraffin is used as a compounding agent. The actual mixture is obtained by mixing gum rosin with starch granules and a mixture enhancer in a ratio of 1 :0.43 ~ 2.3:0.15 ~ 0.33.

From the Chinese patent description CN1115966C is known the method of obtaining a biodegradable foaming material based on vegetable protein, modified starch and a filler in the form of cellulose fibers with metal salt hydrate, added to improve the mechanical properties of the product, and based on citric acid and sodium bicarbonate acting as endothermic blowing agents. The mixture preferably contains from 10 to 46 % by weight of vegetable protein - soy or animal protein in the form of casein, albumin, gelatin, collagen, keratin, or mixtures thereof, from 20 to 46% starch in the form of native starch, or chemically modified starch, or mixtures thereof. Among native starches are corn starch, potato starch, sweet potato starch, tapioca starch, sorghum starch or a mixture of the above. The content of the plasticizer, preferably in the form of ethyl glycol or glycerol, is in the range of 5 to 25%, water in the range of 8 to 20%, while the hydrate of salts such as calcium, sodium, potassium, among others, is in the range of 0.5 to 5% by weight. Natural cellulose fibers represent 5 to 25% by weight of the blend. Chemical or physical phosphors, nucleating agents, lubricants in the form of vegetable oils and other modifiers are also used. The mixture is produced in one of the ways by mixing, extrusion with a single or twin screw extruder to produce granulate, and processing by injection or extrusion. In examples of manufacturing a biodegradable material, glutaraldehyde is also used to cross-link the protein and possibly bind it to starch and cellulose. The introduction of glutaraldehyde into the composition of the material presents the danger of its unreacted residues penetrating into the environment. U.S. patent US11 ,168,203B2 discloses a method for obtaining thermoplastic starch. Starch, e.g. corn, potato, tapioca or rice starch is blended with polyol, mono-, disaccharide, fatty alcohol or a mixture thereof (for example: polyethylene glycol, glycerol, sorbitol) in an amount of 10-25% by weight and epoxidized vegetable oil (e.g. soybean, flaxseed, sunflower) in an amount of 0.1 to 6%, preferably in an amount of 2.5 to 3.5%. In addition, an acid is used, preferably a carboxylic acid from the group: citric acid, malic acid or tartaric acid in an amount of 0.1 -0.5% by weight. The mixture is obtained by extrusion using a twin screw extruder in the temperature range of 100-175°C, at the speed of 250 rpm. The product is subsequently subjected to granulation.

In turn, US application US5451673A discloses a method of obtaining films from aqueous solutions based on a mixture of pectin, without the addition of calcium cations, with starch and an optional plasticizer. The starch is mixed with water and gelatinized at the boiling point of the water under pressure, then cooled (e.g., in a water bath) and mixed with the pectin solution for about 1 hour. The material is poured to produce films that have been vacuum dried.

U.S. patent application US2012/0283364A1 discloses a method of obtaining a polymer blend with thermoplastic starch for processing by extrusion or injection molding. The first step is to obtain thermoplastic starch by mixing starch, water and plasticizer and undergoing mechanical and thermal processing, as well as draining the water. In the next step, a blend of synthetic polymers, e.g. PHBV and PVOH, is combined with a finished blend of dehydrated thermoplastic starch using an extrusion process. Optionally, the utility shape of the resulting mixture is given.

European Patent EP2473542B1 discloses a method for obtaining a biodegradable polymer blend with a thermoplastic starch, which includes mixing the pre-mix with one or more biodegradable polyesters having a melt flow index (MFI) of not more than 5 g/10 min, preferably a polymer of the group: PCL, PBAT, PHBV, PES and PBS, with the pre-mix consisting of polyalkylene carbonate, thermoplastic starch, a polymer containing carboxylic acid groups and a transesterification catalyst such as sodium or potassium hydroxide. The starch can be corn starch, potato starch, wheat starch, tapioca starch, soybean starch or a mixture thereof, while the plasticizer is preferably glycerin and/or sorbitol. The ratio of starch to plasticizer is 2:1 to 3:1.

U.S. patent description US 8852747B2 discloses a method of obtaining thermoplastic multilayer products obtained by co-extruding a layer obtained from polymer A in the form of a renewable/biodegradable, polylactide, homopolymers or poly hydroxyalkanoate copolymers e.g. PHB, PHBV, polyalkylene succinates e.g. PBS. PBS, which are grafted with a monomer from the group of unsaturated carboxylic acids; a layer composed of polymer B, which is identical to polymer A, but is not grafted, the composition of the multilayer product also includes component C - a plasticizer from the group of polymers, oligomers or prepolymers, e.g. polyethylene glycol multilayer product, and there is also a starch material D in the form of thermoplastic starch. The product is manufactured by co-extrusion on a twin screw extruder.

From U.S. patent US7,297,394B2 a method of obtaining a biodegradable composition for use as coatings and materials for packaging is known. The composition consists, preferably, of at least one biodegradable rigid polymer, preferably from the group of, among others, polyesteramides, lactic acid-based polymers, and also consists of polyhydroxybutyrate or starch, also consists of at least one biodegradable flexible polymer (preferably, among others, PHBV, PCL, PBS) and optionally a filler (e.g., talc, silica). Compositions are obtained by extrusion on an extruder.

US patent US 5756194 A discloses a method of obtaining a biodegradable water-resistant material consisting of a core made of gelled starch and a layer of gum rosin, which is an intermediate layer between the starch and a coating made of biodegradable polyester, e.g. PLA, PHBV, PCL. A layer made of gum rosin is obtained by spraying an alcoholic gum rosin solution on the starch product, and then coating it with a suitable solution of the selected polyester, for example, in tetra hydrofuran.

European patent EP3 064542B1 discloses a method for manufacturing a biodegradable composition based on TPS thermoplastic starch and PLA polylactide. The thermoplastic starch blend is obtained by mixing native starch with a plasticizer, such as glycerin, and extruding using a single- or twin-screw extruder in a thermomechanical process, with starch accounting for 30 to 80.8 percent by weight, glycerin 10 to 48.5 percent by weight, and modifying additives in the form of agar 2 to 20 percent by weight and/or epoxidized vegetable oil 0.5 to 10 percent by weight and/or gum arabic 0.5 to 10 percent by weight. The resulting TPS is then granulated, mixed with PLA granulate at a ratio of 7:1 to 1 :7, and extruded.

A scientific article Films Based on Thermoplastic Starch Blended with Pine Resin Derivatives for Food Packaging by C. Pavon and collaborators, published in 2021 , reveals the preparation of TPS thermoplastic starch that contained 10 wt.%. of various pine resin derivatives: gum rosin, disproportionated gum rosin, modified gum rosin with maleic anhydride, pentaerythritol gum rosin esters and gum rosin glycerol esters. Thermoplastic starch was obtained by mixing native starch with plasticizer - glycerin, water and appropriate modifiers, and then the mixtures were extruded. Tests have shown that pine resin derivatives increase the hydrophobicity of TPS, thereby reducing water absorption by TPS and affecting the stiffening of its structure. The invention disclosed in international patent application WO2009155511A2 relates to a method for producing a meat food product having a casing, which method includes the step of applying a casing paste containing alginate and a hard-soluble calcium salt by co-extrusion to the outside of the meat material, to be cased to form a water-resistant product, also relates to a method of obtaining a co-extruded meat product whose water resistance is obtained by contacting the co-extruded product with a solution containing calcium ions, thereby causing the alginate to gel on the surface of the meat material.

U.S. patent description US9770044B2 discloses an edible chewing product for pets containing 10%-30% by weight of meat component and 20%-50% by weight of vegetable starch, said chewing product further comprising the addition of compounds from the group of: thickeners (including, but not limited to. vegetable proteins, pectin gum arabic, potassium alginate, gelatin, agar, gum arabic, sodium carboxymethylcellulose), humectants (e.g. glycerin, vegetable proteins), emulsifiers (e.g. vegetable proteins, fatty acids), gelatinizers (vegetable protein isolates, gelatin, pectin, agar, among others), binders (gelatin, pectin, agar, sodium alginate) and fillers (vegetable proteins and starches). The product is a product obtained by extrusion, whereby the said material is heat-treated to at least 40°C and formed into a sheet before extrusion. The document did not disclose the addition of calcium salts to physically cross-link the mixture of proteins, starches and pectins to increase their water resistance.

International patent documentation W02006130025A1 discloses a thermoplastic expanded food composition containing, at a minimum, insoluble milk protein (casein) and non-bull starch, as well as preservatives, flavors, food colorants, vitamins, food acids, phosphates or mixtures thereof, and optionally calcium salts in the role of a nucleating agent designed to accelerate the boiling of water in the extrudate, in a manner that is more controlled than if the nucleating agent were not present. In the composition, no glycerin was used as a plasticizer, as a result, the product after extrusion was in the form of a stiff and brittle foam, the usefulness of which is limited to food purposes only.

On the other hand, US patent application US5451673A discloses an invention for films made from aqueous solutions of pectin-starch mixtures and glycerol, as a plasticizer to increase the flexibility of the film. Films obtained by the method according to the invention have a high elastic modulus are flexible and self-supporting, and have the advantage that all materials are derived from plant products.

The documentation of international patent application WO1994025493A1 discloses the invention of flexible films with a high elastic modulus, which can be produced from aqueous solutions of mixtures of pectin, starch and possibly plasticizers such as glycerin. The films are biodegradable, water-soluble, and all the materials used to make them come from agricultural products.

US patent application US5523293A reveals a method for obtaining biodegradable thermoplastic compositions made from the reaction product of soy protein and a starch filler, a reducing agent from the group of sulfites, nitrates and sulfur compounds, and the reaction of a plasticizer in the form of glycerol, water and possible additives, if desired. The composition has a high degree of fluidity for processing by extrusion and injection molding into solid articles that are biodegradable and have a high degree of tensile strength and water resistance.

The prior art shows that thermoplastic starch (TPS) is currently one of the few types of biodegradable polymers, of natural origin, that can be successfully converted into usable products using processing technologies specific to thermoplastics. However, TPS is not free of disadvantages, among which are its high hygroscopicity and susceptibility to dissolution in water, as well as its low mechanical strength and brittleness. Increasing the mechanical resistance of TPS can be realized by increasing the proportion of native starch, relative to the plasticizer, but this comes at the expense of increasing susceptibility to brittle fracture. On the other hand, increasing the proportion of plasticizer in the composition of TPS allows to obtain flexible products, but characterized by very low tensile strength, high plasticity and high susceptibility to swelling and dissolution in water. Also known from the prior art are ways to increase the mechanical strength and water resistance of thermoplastic starch by creating various types of TPS polymer biocompositions involving compostable polylactide (PLA), poly[adipate-co-terephthalate- 1 ,4-butylene] (PBAT), polybutylene succinate (PBS) or polycaprolactone (PCL). However, the aforementioned plastics are synthetically or semi-synthetically derived materials and have poor biodegradability in the aquatic environment, as well as in the soil. On the other hand, increasing the proportion of thermoplastic starch in such compositions above 50 wt. % makes these materials susceptible to swelling and disintegration when exposed to water.

Market and social pressures, as well as legislative requirements, force the need to create a polymer plastic or polymer compositions in which the polymer components are exclusively of natural origin, are not the result of chemical modification of such polymers, and are biodegradable both in the compost environment and in water and soil, so as not to burden the polymer waste collection and management system with them, and in the event of uncontrolled release into the environment, they would spontaneously biodegrade in due time, under the influence of microorganisms and environmental factors, without releasing harmful substances or emitting microplastic. In addition, plastics of this type must be characterized by high water resistance, mechanical strength, allowing them to be used in the production of consumer products without the need for changes in existing processing technologies relating to thermoplastics. Market requirements also place a high emphasis on the economic attractiveness of this type of biopolymer materials, with respect to the known and currently used polymeric materials obtained from the processing of oil, natural gas and coal. Also, important is the method of manufacturing and processing this type of polymeric material, which should be characterized by low expenditures of time and energy, and does not require the introduction of an excessive amount of additional energy-intensive unit operations and costly additional manufacturing and processing equipment in the process of obtaining it.

Biodegradable thermoplastic polymeric composition constituting a mixture containing native starch and additives in the form of plasticizers, gelling agents, proteins, substances modifying physical properties, hydrophobizing substances, fillers enhancing mechanical strength, compatibilizers and possibly polyester of natural origin is characterized according to the invention in that, on a total weight basis, the composition contains from 42.7 wt.% to 70.2 wt.% native starch, from 19.0 wt.% to 32.5 wt.% of plasticizer, advantageously glycerol, from 0.1 wt.% to 20.0 wt.% of proteins advantageously containing in their structure substances selected from the group comprising amino acids such as glutamic acid, aspartic acid, advantageously in the form of gluten, casein, potato protein isolate, pea protein isolate, soy protein isolate, gelatin, collagen, or a mixture thereof, from 0.1 wt.% to 10.0 wt.% of natural polyester, to 10.0 wt.% of natural gelling substances selected from the group including pectin, alginic acid sodium salt, from 0.1 wt. % to 5.0 wt.%. a physical ionic modifier in the form of a carrier of at least divalent metal cations, preferably calcium salts, from 0.1 wt.% to 12.0 wt.%. hydrophobizing substances of natural origin, selected from the group including gum rosin, glycerin esters of gum rosin, pentaerythritol esters of gum rosin, gum rosin dimers, stearic acid esters preferably glycerol monostearate, salts of stearic acid, preferably magnesium stearate, calcium stearate, zinc stearate, vegetable oils, preferably soybean oil, sunflower oil, rapeseed oil, linseed oil, olive oil, powder hydrophobizing substances, preferably amber dust, or mixtures thereof, from 0.1wt.% to 20.0 wt.% of natural mechanical strength enhancing fillers selected from the group including cellulose fibers, wood dust, cork dust, pulp, from 0.1 wt.% to 2.5 wt.% of cellulose filler compatibilizer and hydrogen interaction inducer with components containing polar functional groups, in the form of sodium tetraborate.

Preferably, the native starch is potato and/or corn starch. Preferably, the calcium salt is calcium chloride.

Preferably, it additionally contains from 12.5 wt.% to 87.5 wt.% poly hydroxyalkanoates preferably poly(3-hydroxybutyrate-co-3-hydroxyvalerate) on the final weight of the composition.

A method for manufacturing a biodegradable thermoplastic composition constituting a mixture containing native starch and additives in the form of plasticizers, gelling agents, proteins, substances modifying physical properties, hydrophobizing substances, fillers enhancing mechanical strength, compatibilizers and possibly polyester of natural origin involving the steps of mixing, extrusion, cooling and granulation is characterized according to the invention in that it is carried out in two stages. In the first step, using a mechanical mixer, at a temperature in the range of 20-60°C, advantageously at 25°C, is mixed on a total weight basis from 42.7 wt.% to 70.2 wt.% of native starch, from 19.0 wt.% to 32.5 wt. % of plasticizer, advantageously glycerol, from 0.1 wt.% to 20.0 wt.% proteins advantageously containing in their structure substances selected from the group comprising amino acids such as glutamic acid, aspartic acid, advantageously in the form of gluten, casein, potato protein isolate, pea protein isolate, soy protein isolate, gelatin, collagen, or mixtures thereof from 0.1 wt.% to 10.0 wt.% of natural gelling substances selected from the group including pectin, sodium salt of alginic acid, from 0.1 wt.% to 5.0 wt.% of physical ionic modifier, a physical ionic modifier in the form of a carrier of at least divalent metal cations, preferably calcium salts, from 0.1 wt.% to 12.0 wt.%. hydrophobizing substances of natural origin, selected from the group including gum rosin, gum rosin glyceryl esters, gum rosin pentaerythritol esters, gum rosin dimers, stearic acid esters advantageously glycerol monostearate, stearic acid salts, favorably magnesium stearate, calcium stearate, zinc stearate, vegetable oils, favorably soybean oil, sunflower oil, rapeseed oil, linseed oil, olive oil, powder hydrophobizing substances, favorably amber dust, or mixtures thereof, from 0.1 wt.% to 2.5 wt.% of cellulose filler compatibilizer and hydrogen interaction inducer with components containing polar functional groups, in the form of sodium tetraborate. During mixing, it is important not to keep the temperature of the mixture above 60°C in order to counteract the gelatinization of starch and the melting of hydrophobic substances, which in their molten state can increase the stickiness of the mixture. Then, to the mixture obtained in this way, natural fillers for enhancing mechanical strength selected from the group including cellulose fibers, wood dust, cork dust, cellulose pulp in the amount of 0.1 wt.% to 20.0 wt.% are added, and the whole mixture is blended for up to 30 minutes, preferably up to 15 minutes. In the second stage, the starch mixture obtained in the first stage is subjected to extrusion immediately after it is made with the extruder while maintaining the temperature of the heating zones of the plasticizing system in the range from 100°C to 190°C, preferably in the range from 100°C to 165°C with simultaneous degassing of volatile parts, and then the obtained extrudate is cooled by forced air circulation to room temperature and subjected to granulation.

Preferably, the native starch is potato and/or corn starch.

Preferably, the calcium salt is calcium chloride.

Preferably, in the second step, additionally 12.5 wt% to 87.5 wt% of polyhydroxyalkanoates preferably poly(3- hydroxybutyrate-co-3-hydroxyvalerate) are added to the extruder hopper on the final weight of the composition.

Preferably, in the second stage, additionally, 12.5 wt% to 87.5 wt% of polyhydroxyalkanoates preferably poly(3-hydroxybutyrate-co-3-hydroxyvalerate) are added to the extruder in a stream of plasticized starch mixture at least half the length of the plasticizing zone (L/2) by means of a side dispenser, per final weight of the composition.

Preferably, the extruder is an extrusion device divided into temperature-controlled heating zones including the hopper, plasticizing system and head, preferably a single screw or multi screw device.

Another invention is a method for obtaining a biodegradable thermoplastic composition constituting a mixture containing native starch and additives in the form of plasticizers, gelling agents, proteins, substances modifying physical properties, hydropho- bizing substances, fillers enhancing mechanical strength, compatibilizers and possibly polyester of natural origin comprising the steps of mixing, extrusion, cooling and granulation characterized in that it is carried out in one step using an extruder. Into the extruder in the feed zone is dosed, on a total weight basis, from 42.7 wt.% to 70.2 wt.% of native starch, from 19.0 wt.% to 32.5 wt.% of plasticizer, advantageously glycerol, from 0.1 wt. % to 20.0 wt.% of proteins advantageously containing substances in their structure, selected from the group including amino acids such as glutamic acid, aspartic acid, advantageously in the form of gluten, casein, potato protein isolate, pea protein isolate, soy protein isolate, gelatin, collagen, or a mixture thereof, from 0.1 wt.% to 10.0 wt.% of natural gelling agents selected from the group including pectin, alginic acid sodium salt, from 0.1 wt.% to 5.0 wt.% of a physical ionic modifier in the form of a carrier of at least divalent metal cations, preferably calcium salts, from 0.1 wt.% to 12.0 wt.%. hydrophobizing substances of natural origin, selected from the group including gum rosin, gum rosin glyceryl esters, gum rosin pentaerythritol esters, gum rosin dimers, stearic acid esters advantageously glycerol monostearate, stearic acid salts, favorably magnesium stearate, calcium stearate, zinc stearate, vegetable oils, favorably soybean oil, sunflower oil, rapeseed oil, linseed oil, olive oil, powder hydrophobizing substances, favorably amber dust, or mixtures thereof, from 0.1 wt.% to 20.0 wt.% of natural mechanical strength enhancing fillers selected from the group including cellulose fibers, wood dust, cork dust, pulp, from 0.1 wt.% to 2.5 wt.% of cellulose filler compatibilizer and hydrogen interaction inducer with components containing polar functional groups, in the form of sodium tetraborate. If the plasticizer or hydrophobizing substance is in liquid form, it is dosed in the first zone of the plasticizing system, located directly behind the bulk component backfill zone. The temperatures of the heating zones of the plasticizing system are maintained in the range from 100°C to 190°C, preferably from 100°C to 165°C with simultaneous degassing of volatile parts, and then the thermoplastic extrudate thus obtained is cooled with air to room temperature and subjected to granulation.

Preferably, the native starch is potato and/or corn starch.

Preferably, the calcium salt is calcium chloride.

Preferably, additionally, 12.5 wt.% to 87.5 wt.% polyhydroxyalkanoates preferably poly(3-hydroxybutyrate-co-3- hydroxyvalerate) are added to the extruder hopper on a final weight basis.

Preferably, additionally, 12.5 wt.% to 87.5 wt.% polyhydroxyalkanoates are added to the extruder in a stream of plasticized starch mixture at least half the length of the plasticizing zone (L/2) by means of a side dispenser preferably poly(3-hydroxybutyrate-co- 3-hydroxyalkanoate) on a final weight basis.

Preferably, the extruder is an extrusion device divided into temperature-controlled heating zones including the hopper, plasticizing system and head, preferably a single screw or multi screw device.

The abbreviations and acronyms used in this description have the following meanings: rhTPS stands for reinforced and hydrophobized thermoplastic starch, ST stands for starch, GL stands for vegetable glycerin, BRX stands for sodium tetraborate (borax), GEL stands for natural gelling agents, which include PEC -pectins, sodium salt of alginic acid, P stands for proteins advantageously containing in their structure amino acids such as glutamic acid and/or aspartic acid with active carboxyl groups to which include CAS - casein (milk protein), VPI - vegetable protein isolate (potato, pea, soybean), GET - food gelatin, COL - collagen, FM - stands for physical ionic modifier in the form of calcium chloride (CaCI2), H stands for hydrophobizing substances which include gum rosin (RO), gum rosin pentaerythritol esters (RPE), gum rosin glycerin esters (RGE), gum rosin dimer (RD) stearic acid salts (STS), preferably magnesium stearate STSMg and/or calcium stearate STSCa, vegetable oil (VO), preferably soybean oil, and/or sunflower oil, and/or rapeseed oil, and/or linseed oil, and/or olive oil, and/or amber dust (AMB), LCF stands for cellulose reinforcing fibers, LCP stands for cellulose powders or dust, CO stands for cork dust, RH stands for rice husk, PHA stands for polyhydroxyalkanoates, advantageously poly(3- hydroxybutyrate-co-3-hydroxyvalerate) (PHBV).

It should be noted that all the components used to obtain rhTPS and the rhTPS/PHA biocomposition that is the subject of the invention are of natural origin, including plant, animal and bacterial, and some of them may be derived from renewable sources.

Modification of the physical properties of thermoplastic starch and its compatibility with cellulose fillers is realized by means of sodium tetraborate (borax) mediated by which physical hydrogen interactions between -OH groups contained in starch and -OH groups present in cellulose are induced. Sodium tetraborate will also make it possible to induce physical hydrogen interactions between starch, other components such as gelling agents and proteins.

In turn, the use of polyhydroxyalkanoate (PHA), preferably polyhydroxybutyrate (PHB), poly-3-hydroxyvalerate (PHV), more preferably poly(3-hydroxybutyrate-co-3- hydroxy valerate) (PHBV) in the composition according to the invention has a significant effect on achieving its high mechanical strength, while starch reinforced and hydrophobized with natural compounds (rhTPS) is expected to improve the processing parameters, flexibility, functional properties and accelerate the biodegradation of the rhTPS/PHA composition. The role of PHA in composition with rhTPS is also to induce a barrier to water access. In addition, PHAs, including PHBV, are natural polymers produced by bacteria or cyanobacteria and archaeons, as a backup material for these organisms. In addition, PHBV is one of the few biopolymers that is biodegradable in seawater, freshwater and soil without being composted under industrial conditions. The obtained biodegradable material is characterized by desirable processing and physical and mechanical properties, as well as the usability of products made from it, i.e. disposable and reusable products or packaging materials, etc.

The purpose of the invention is to obtain, based on the components used, which are of natural origin or obtained from natural raw materials, a thermoplastic starch showing high barrier to water access and high resistance to dissolution in water. This was realized by using gelling agents used in the food industry in the form of pectin, or optionally using modification products of natural gelling agents, such as alginic acid sodium salt, in combination with proteins, advantageously containing in their structure amino acids such as glutamic acid and/or aspartic acid with a free carboxyl group, advantageously in the form of, for example, gluten, and/or casein (whey protein) and/or potato protein isolate and/or pea protein isolate and/or soy protein isolate and/or dietary gelatin and/or collagen. The combination of gelling carbohydrates and starch with proteins enables the formation of interpenetrating protein-polysaccharide polymer networks in the rhTPS mass, in which there are strong interactions based on coacervation, i.e. adsorption of a negatively charged anionic polysaccharide, mainly a gelling polysaccharide, on the su rface of a positively charged protein. This promotes the formation of a strong gel system that acts as a barrier to the dissolution of starch under the influence of water. Coacervation is the process of physically binding a protein-polysaccharide system into a stiffened polymer network, dependent on maintaining the appropriate pH level in the starch material. To maintain this physically cross-linked system, it is required to keep the pH in rhTPS below the isoelectric point of the protein used in the system, so that a net positive charge is generated on the surface of its macromolecules. In the material according to the invention, the maintenance of the appropriate pH is realized, for example, by the addition of gum rosin. The process of enhancement of rhTPS by coacervation is assisted in the material according to the invention by bridging the anionic groups present in both the gelling agent and the free carboxyl groups present in the proteins used via divalent metal cations present in the ionic modifiers used. In addition, the presence in the composition of rhTPS of gelling agents of natural origin, such as pectin, and gelling agents obtained by modification of natural raw materials, such as sodium alginate, and physical ionic modifiers, in the form of calcium salts, allows them to be physically enhanced by direct contact with water. In the thermoplastic starch according to the invention, the dry gelling agent and the dry ionic modifier are mixed with the thermoplastic starch in its molten state, as a result of which they are well dispersed throughout its volume. Contact of the starch material with water results in immediate, reversible gelling of the gelling polysaccharide and the formation of a barrier ion-polysaccharide membrane that can swell and absorb water, but stops the release of all the components present in the thermoplastic starch composition. If this gelled structure is mechanically disturbed, it is immediately restored when the exposed layers of material come into contact with water. The loss of ions, due to their high desorption capacity into the aqueous environment, is also reproduced by the availability of cations in the deeper layers of the material, as a result of which, in terms of the service life of products made of thermoplastic starch according to the invention, its mechanical and functional properties are preserved. The system is also environmentally safe, as the gelling agents used are fully biodegradable and compostable, and in the case of thermoplastic starch biodegradation in water, the first step is desorption of metal cations into water, followed by polysaccharide biodegradation, with the process being much faster in the case of seawater, due to the desorption and ion exchange of cations occurring via sodium ions and chloride anions.

In order to hydrophobize thermoplastic starch, the invention uses stearic acid derivatives in the form of magnesium stearate and/or calcium stearate and/or zinc stearate, as well as pine gum rosin and/or its derivatives in the form of gum rosin pentaerythritol esters, gum rosin glycerin esters and gum rosin dimers, which are non-toxic, biodegradable and used in the food industry, among others. Due to the amphiphilic nature of stearic acid and its salts, they interact with both hydrophilic and hydrophobic components of rhTPS and rhTPS/PHA compositions, acting as a compatibilizer for the miscibility of their components and providing enhanced surface hydrophobicity of these materials. On the other hand, due to the presence in gum rosin of abietic and pimaric type acids with characteristic hydrophenanthrene ring structures, it is characterized by high hydrophobicity. In turn, the presence of gum rosin and, in its derivatives, highly polar groups also ensures its good interaction, via hydrogen bonds, with both native starch, glycerol and the other components used to obtain rhTPS and having hydroxyl or other polar groups in their structure. On the other hand, hydrophobic cyclic rings of gum rosin acids ensure good interaction with a hydrophobic polyester, such as PHA, and water resistance of the biocompositions obtained by the method according to the invention. The resulting "bridging" effect provides the basis for interfacial compatibilization of rhTPS with PHA, mediated by salts of stearic acid and gum rosin and its derivatives, also providing increased water resistance of rhTPS. On the other hand, the use of vegetable oils (VO), advantageously soybean oil, and/or sunflower oil, and/or rapeseed oil, and/or linseed oil, and/or olive oil as a modifying additive for rhTPS to obtain the thermoplastic starch according to the invention, allows the compatibility of rhTPS with PHA, advantageously PHBV or other types of hydrophobic polyesters such as PLA, PBT, PSB, for example, which has a significant effect on increasing the strength of the compositions and improving their processing properties. The nature of these interactions is due to the amphiphilic structure of the natural oil, which has areas of high hydrophilicity in the molecule that allow it to induce hydrogen interactions with polar rhTPS components and hydrophobic areas that interact with hydrophobic polyesters in the composition. The use of amber dust with high hydrophobicity and the ability to generate negatively polarized electrical charges on the surface of the grains makes it possible, on the one hand, to excite the hydrophobic character of rhTPS and to induce induced interactions with other components and electrostatic interactions with positively charged protein molecules in an environment below their pH(l) isoelectric point. The enhancement of the mechanical properties of thermoplastic starch, as well as its composition with PHA in the invention, is realized by using cellulose fillers in the form of cellulose fibers, and/or cellulose dust, and/or shredded vegetable pulp as reinforcement. Preferably, the invention uses cellulose fibers as reinforcement. Cellulose fibers, due to their hydrophilic nature and ability to interact with water, are added to rhTPS and its composition with PHA in combination with gum rosin, which is capable of compatibilizing cellulose with a hydrophobic polyester like PHA. Gum rosin, as well as the method of obtaining rhTPS, also makes it possible to achieve the effect of impregnating cellulose fibers with it.

The biodegradable, thermoplastic, reinforced and hydrophobic starch-based polymer composition according to the invention consists exclusively of components of natural origin and/or components obtained from renewable raw materials. It is obtained in the dry state without the operation of dissolving components and intermediates in water, undergoes physical self-reinforcement in contact with water under the influence of divalent and/or trivalent metal ions. It is stable during use, and the products made from it are fully biodegradable, including in fresh and seawater and soil, while maintaining the desired physical, mechanical and functional properties. A biocomposition composed of thermoplastic starch and polyhydroxyalkanoates (PHAs) of natural origin is obtained according to the invention so that no chemical modification of the starch is used, and its composition is chosen to induce interaction between the individual components solely through physical interactions.

The invention is explained in more detail in the performance examples, which do not limit its scope.

The invention is explained in more detail in the presented manufacturing examples, which include a planetary mixer, an extruder equipped with modular heating zones and a heated head and granulator knife, an injection molding machine using which paddleshaped samples with dimensions in accordance with PN- ISO 37:2007 were obtained. The specimens obtained according to the examples were subjected to tests of their tensile strength and elongation at rupture according to PN- ISO 37:2007 standard, and the wetting angle was determined for them using a goniometer (Rame-Hart instrument).

To obtain samples by the methods according to the invention, we used potato starch (NOWAMYL" S.A.), corn starch (Biomus sp. z o.o.), vegetable glycerol 99.5% (TechlandLab sp. z o.o.), glycerol monostearate (LOUIS FRANQOIS), calcium stearate (Warchem Sp. z o.o.), magnesium stearate (Europharma invest Sp. z o.o. ), zinc stearate (Warchem Sp. z o.o.), soybean oil (Heuschen & Schrouff), sunflower oil (Golden Eggs), rapeseed oil (ZT Kruszwica S.A. ), flaxseed oil (Brenntag), and/or olive oil (Urzante), sodium alginate (Biomus sp. z o.o.), pectin (Natural Health), calcium chloride (Warchem Sp. z o.o.), sodium tetraborate (Biomus sp. z o.o. ), pea protein isolate (Medicaline), potato protein (NOWAMYL S.A.), soy protein isolate (SFD S.A.), casein (ARTE METAL STYLE POLSKA Spolka z o.o.), wheat gluten (Kol-Pol), food grade gelatin (Mr Cook Corp.), collagen (Kol-Pol), gum rosin (PinoPine), gum rosin pentaerythritol ester, (PinoPine), gum rosin glycerin ester (PinoPine), dimerized gum rosin (PinoPine), coffee grounds (Starbucks Gdansk), sterilized rice husk (ROBNET Robert Kwiecinski), cork dust (KORK. PL sp. z o.o.), wood dust (RETTENMAIER Polska Sp. z o.o.), cellulose fiber (RETTENMAIER Polska Sp. z o.o.), amber dust (Alkor), poly(3- hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) (PHI002, NaturePlast).

Example 1

A potato starch composition of 65.6 wt.%, 21.9 wt.% glycerol, 0.5 wt.% pectin, 10 wt.% gluten, 0.25 wt.% calcium chloride, 0.5 wt.% gum rosin, 1.0 wt.% cellulose fibers and 0.25 wt.% sodium tetraborate was prepared. The mixing process of all ingredients was carried out in a standard mechanical mixer for 30 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 60-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 1 .

Example 2

A potato starch composition of 58.7 wt.%, with 29.3 wt.% glycerol, and with 0.5 wt.% pectin, 1.0 wt.% gluten, 0.25 wt.% calcium chloride, 5.0 wt.% gum rosin dimer, 5.0 wt.% wood flour and 0.25 wt.% sodium tetraborate was prepared. The mixing process of all ingredients was carried out in a standard mechanical mixer for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of a co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the range of 100-175°C and a screw speed of 100 rpm. It was further proceeded as in example 1. Table 1 shows the properties of the thermoplastic starch obtained according to Example 2.

Example 3

A potato starch composition of 58.7 wt% was prepared, with 29.3 wt% glycerol, and 0.5 wt % pectin, 1.0 wt% gluten, 0.25 wt% calcium chloride, 5.0 wt% gum rosin, 5.0 wt% cellulose fibers and 0.25 wt% sodium tetraborate. The mixing process of all ingredients was carried out in a standard mechanical mixer for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 60-185°C and a screw speed of 100 rpm.

It was further proceeded as in example 1. Table 1 shows the properties of the thermoplastic starch obtained according to Example 3.

Example 4

A potato starch composition of 57.0 wt.%, with 19.0 wt.% glycerol, and with 10.0 wt.% pectin, 1.0 wt.% gluten, 5.0 wt.% calcium chloride, 0.5 wt.% glycerol monostearate, 5.0 wt. % cellulose fibers and 2.5 wt.% sodium tetraborate was prepared. The mixing process was carried out in a standard mechanical mixer for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of a co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the range of 60-190°C and a screw speed of 100 rpm. It was further proceeded as in Example 1. As a result of the high pectin and calcium chloride content, the resulting extrudate was highly rigid and foamy, allowing it to be used as a waterproof filling for mail parcels. Table 1 shows the properties of the thermoplastic starch obtained according to Example 4.

Example 5

A potato starch composition of 49.0 wt.%, with 24.5 wt.% glycerol, and with 0.5 wt.% pectin, 0.5 wt.% gluten, 0.25 wt.% calcium chloride, 5.0 wt.% glycerol monostearate, 20.0 wt.% cellulose fibers and 0.25 wt.% sodium tetraborate was prepared. The mixing process was carried out in a standard mechanical mixer for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the range of 100-165°C and a screw speed of 100 rpm. It was further proceeded as in example 1. Table 1 shows the properties of the thermoplastic starch obtained according to Example 5.

Example 6

A 42.7 wt.% potato starch composition was prepared in a standard mechanical mixer, with 21.3 wt.% glycerol and 0.5 wt.% pectin, 10.0 wt.% gluten, 0.25 wt.% calcium chloride, 5.0 wt.% pentaerythritol gum rosin ester, 20.0 wt.% wood dust and 0.25 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. It was further proceeded as in example 1. Table 1 shows the properties of the thermoplastic starch obtained according to Example 6.

Example 7

A potato starch composition of 42.7 wt.% was prepared in a standard mechanical mixer, with 21 .3 wt.% glycerol and 0.5 wt.% pectin, 10.0 wt.% gluten, 0.25 wt.% calcium chloride, 5.0 wt.% gum rosin glycerin ester, 20.0 wt.% wood dust and 0.25 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. It was further proceeded as in example 1. Table 1 shows the properties of the thermoplastic starch obtained according to Example 7.

Example 8

A 48.1 wt.% potato starch composition was prepared in a standard mechanical mixer, with 24.0 wt.% glycerol and 0.1 wt.% pectin, 0.1 wt.% gluten, 0.1 wt.% calcium chloride, 7.5 wt. % gum rosin, 20.0 wt.% wood dust and 0.1 wt.% sodium tetraborate.

The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. It was further proceeded as in example 1. Table 1 shows the properties of the thermoplastic starch obtained according to Example 8.

Example 9

A 65.1 wt.% corn starch composition was prepared in a standard mechanical mixer, with 32.5 wt.% glycerol and 0.1 wt.% pectin, 0.1 wt.% gluten, 0.1 wt.% calcium chloride, 1.0 wt. % magnesium stearate, 1.0 wt.% cork dust and 0.1 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of th e device in the following range of 100-165°C and a screw speed of 100 rpm. It was further proceeded as in example 1. Table 1 shows the properties of the thermoplastic starch obtained according to Example 9.

Example 10

A 65.0 wt.% potato starch composition was prepared in a standard mechanical mixer with 32.5 wt.% glycerol, along with 0.1 wt.% pectin, 0.1 wt.% gluten, 0.1 wt.% calcium chloride, 1.0 wt.% magnesium stearate, 1.0 wt.% amber dust, 0.1 wt.% wood dust and O.1 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. It was further proceeded as in example 1. Table 1 shows the properties of the thermoplastic starch obtained according to Example 10.

Example 11

A composition consisting of 65.1 wt% potato starch with 32.5 wt% glycerol and 0.1 wt% sodium alginate, 1.0 wt% collagen, 0.1 wt% calcium chloride, 1.0 wt% magnesium stearate, 0.1 wt% cellulose fibers and 0.1 wt% sodium tetraborate was prepared in a standard mechanical mixer. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. It was further proceeded as in example 1. Table 1 shows the properties of the thermoplastic starch obtained according to Example 11.

Example 12

A 65.1 wt.% potato starch composition was prepared in a standard mechanical mixer, with 32.5 wt.% glycerol, and 0.1 wt.% pectin, 0.1 wt.% gluten, 0.1 wt.% calcium chloride, 1.0 wt.% magnesium stearate, 1.0 wt. rice husk and 0.1 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the planetary extruder and subjected to the extrusion process, maintaining the temperature in the successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 12.

Example 13

A 59.1 wt.% potato starch composition was prepared in a standard mechanical mixer, with 29.5 wt.% glycerol and 0.1 wt.% pectin, 0.1 wt.% gluten, 0.1 wt.% calcium chloride, 1.0 wt. % magnesium stearate, 10.0 wt.% cellulose fibers and 0.1 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the single-screw extruder and subjected to the extrusion process, maintaining the temperature in the successive heating zones of the device in the following range of 100-165°C and the screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 13.

Example 14

A corn starch composition of 59.1 wt.%, with 29.5 wt.% glycerol, and 0.1 wt.% pectin, 0.1 wt.% gluten, 0.1 wt.% calcium chloride, 1.0 wt.% calcium stearate, 10.0 wt.% cellulose fibers and 0.1 wt.% sodium tetraborate were prepared in a standard mechanical mixer. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the planetary extruder and subjected to the extrusion process, maintaining the temperature in the successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 14.

Example 15

A 56.4 wt.% potato starch composition was prepared in a standard mechanical mixer, with 28.2 wt.% glycerol and 0.1 wt.% pectin, 0.1 wt.% gluten, 0.1 wt.% calcium chloride, 5.0 wt. % gum rosin, 10.0 wt.% coffee grounds and 0.1 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the single-screw extruder and subjected to the extrusion process, maintaining the temperature in the successive heating zones of the device in the following range of 100-165°C and the screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 15.

Example 16

A 62.6 wt.% potato starch composition was prepared in a standard mechanical mixer, with 25.0 wt.% glycerol and 0.1 wt.% pectin, 0.1 wt.% gluten, 0.1 wt.% calcium chloride, 2.0 wt. % glycerol monostearate, 10.0 wt.% glycerol, rice husk and 0.1 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the planetary extruder and subjected to the extrusion process, maintaining the temperature in the successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 16.

Example 17

A 70.2 wt.% potato starch composition was prepared in a standard mechanical mixer, with 23.4 wt.% glycerol and 0.1 wt.% pectin, 4.0 wt.% gelatin, 0.1 wt.% calcium chloride, 2.0 wt.% glycerol monostearate, 0.1 wt.% cellulose fibers and 0.1 wt.% sodium tetraborate. The mixing process was carried out for 30 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 17.

Example 18

In a standard mechanical mixer, a potato starch composition of 61.9 wt.% was prepared with 24.7 wt.% glycerol and 0.1 wt.% pectin, 0.1 wt.% gelatin, 0.1 wt.% calcium chloride, 3.0 wt.% glycerol monostearate, 10.0 wt.% cellulose fibers and 0.1 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter of grains in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 18.

Example 19

A composition consisting of 61.2 wt.% potato starch, 24.5 wt.% glycerol, and 2.0 wt.% pectin, 0.1 wt.% gluten, 2.0 wt.% calcium chloride, 0.1 wt.% glycerol monostearate, 10.0 wt.% cellulose fibers and 0.1 wt.% sodium tetraborate was prepared in a standard mechanical mixer. The mixing process was carried out for 15 minutes at 20+5 °C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 19.

Example 20

A composition was prepared in a standard mechanical mixer, consisting of 60.1 wt.% potato starch mixed with 24.1 wt.% glycerol and 5.0 wt.% pectin, 10.0 wt.% gelatin, 0.1 wt % calcium chloride, 0.1 wt.% glycerol monostearate, 0.1 wt.% cellulose fibers and 0.5 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20+5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with diameter of grains in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 20.

Example 21

A composition was prepared in a standard mechanical mixer, consisting of 59.7 wt.% potato starch, 29.9 wt.% glycerol, and 5.0 wt.% sodium alginate, 0.1 wt.% gluten, 5.0 wt.% calcium chloride, 0.1 wt.% glycerol monostearate, 0.1 wt.% cellulose fibers and O.1 wt.% sodium tetraborate. The mixing process was carried out for 30 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100 - 165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 21.

Example 22

A composition was prepared in a standard mechanical mixer, consisting of 62.5 wt.% potato starch with 31.2 wt.% glycerol, as well as 2.0 wt.% sodium alginate, 2.0 wt.% potato protein, 2.0 wt.% calcium chloride, 0.1 wt.% glycerol monostearate, 0.1 wt.% cellulose fibers and 0.1 wt.% sodium tetraborate. The mixing process was carried out for 30 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with diameter of grains in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 22.

Example 23

In a standard mechanical mixer, a composition consisting of 59.1 wt% potato starch with 29.5 wt% glycerol was prepared, along with 0.1 wt% pectin, 10.0 wt% casein, 0.1 wt% calcium chloride, 1.0 wt% gum rosin, 0.1 wt% cellulose fibers and 0.1 wt% sodium tetraborate. The mixing process was carried out for 30 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm.

Table 1 shows the properties of the thermoplastic starch obtained according to Example 23.

Example 24

A composition was prepared in a standard mechanical mixer, consisting of 63.1 wt.% potato starch, 31.5 wt.% glycerol, and 0.1 wt.% pectin, 2.5 wt.% gelatin, 0.1 wt.% calcium chloride, 0.1 wt.% gum rosin, 0.1 wt.% cellulose fibers and 2.5 wt.% sodium tetraborate. The mixing process was carried out for 30 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 60-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 24.

Example 25

A composition consisting of 59.1 wt% potato starch, 29.5 wt% glycerol, and 0.1 wt% pectin, 10 wt% casein, 0.1 wt% calcium chloride, 1.0 wt% gum rosin, 0.1 wt% cellulose fibers and 0.1 wt% sodium tetraborate was prepared in a standard mechanical mixer. The mixing process was carried out for 30 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 25.

Example 26

A composition consisting of 61.7 wt.% potato starch, 30.9 wt.% glycerol, and 0.1 wt.% pectin, 5 wt.% pea protein isolate, 1.0 wt.% soy protein isolate, 0.1 wt.% calcium chloride, 1.0 wt.% gum rosin, 0.1 wt.% cellulose fibers and 0.1 wt.% sodium tetraborate was prepared in a standard mechanical mixer. The mixing process was carried out for 30 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the corotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granules of modified thermoplastic starch with a grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 26.

Example 27

A composition consisting of 52.7 wt.% potato starch, 26.4 wt.% glycerol, and 0.1 wt.% pectin, 10.0 wt.% gelatin, 10.0 wt.% gluten, 0.1 wt.% calcium chloride, 0.1 wt.% gum rosin, 0.1 wt.% cellulose fibers and 0.5 wt.% sodium tetraborate was prepared in a standard mechanical mixer. The mixing process was carried out for 30 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 27.

Example 28

In a standard mechanical mixer, a composition was prepared consisting of 62.2 wt.% potato starch, 24.9 wt.% glycerol, and 0.1 wt.% pectin, 0.1 wt.% gluten, 0.1 wt.% calcium chloride, 5.0 wt.% magnesium stearate, 5.0 wt.% gum rosin pentaerythritol ester, 2.5 wt.% cork dust and 0.1 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granules of modified thermoplastic starch with a grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 28.

Example 29

In a standard mechanical mixer, a composition was prepared consisting of 67.5 wt.% potato starch, 27.0 wt.% glycerol, and 0.1 wt.% pectin, 0.1 wt.% gluten, 0.1 wt.% calcium chloride, 5.0 wt.% gum rosin glycerol ester, 0.1 wt.% cellulose fiber and 0.1 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 29.

Example 30

In a standard mechanical mixer, a composition was prepared consisting of 67.5 wt.% potato starch, 27.0 wt.% glycerol, and 0.1 wt.% pectin, 0.1 wt.% gluten, 0.1 wt.% calcium chloride, 5.0 wt.% gum rosin pentaerythritol ester, 0.1 wt.% cellulose fiber and 0.1 wt.% sodium tetraborate. The mixing process was carried out for 15 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The starch mixture obtained in this way, was introduced immediately after mixing into the hopper of the co-rotating twin screw extruder and subjected to the extrusion process, maintaining the temperature in successive heating zones of the device in the following range of 100 - 165°C and a screw speed of 100 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granules of modified thermoplastic starch with a grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 30. Example 31

A composition consisting of potato starch in an amount representing 58.3% of the final weight of the product and pectin in an amount representing 0.1% of the final weig ht of the product and gluten in an amount representing 0.1 % of the final weight of the product was continuously dosed into the hopper of the twin screw extruder using screw dispensers, calcium chloride in an amount representing 0.1 % of the final weight of the product, gum rosin in an amount representing 5% of the final weight of the product, zinc stearate in an amount representing 5% of the final weight of the product, cellulose fibers in an amount representing 0.1% of the final weight of the product, and sodium tetraborate in an amount representing 0.1 % of the final weight of the product. On the other hand, in the first zone of the plasticizing system, located directly behind the zone of loading of loose components, liquid glycerol in an amount of 29.2% of the final weight of the product and soybean oil in an amount of 2% of the final weight of the product were dosed continuously by means of a peristaltic pump. The extrusion process was carried out by maintaining the temperature in successive heating zones of the device in the following range of 100 -165°C and a screw speed of 50 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 31.

Example 32

A composition consisting of potato starch in an amount constituting 69.4% of the final weight of the product, plus pectin in an amount constituting 0.1 % of the final weight of the product, plus gluten in an amount constituting 0.1 % of the final weight of the product, was continuously dosed into the hopper of the twin-screw extruder by means of screw dispensers, calcium chloride in an amount representing 0.1% of the final weight of the product, gum rosin in an amount representing 1.25% of the final weight of the product, calcium stearate in an amount representing 2.0% of the final weight of the product, cellulose fibers in an amount representing 0.1 % of the final weight of the product, and sodium tetraborate in an amount representing 0.1% of the final weight of the product. On the other hand, in the first zone of the plasticizing system, located directly behind the zone of loading of loose components, liquid glycerol in an amount of 23.1 % of the final weight of the product and sunflower oil in an amount of 3.75% of the final weight of the product were dosed continuously by means of a peristaltic pump. The extrusion process was carried out by maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 50 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm. Table 1 shows the properties of the thermoplastic starch obtained according to Example 32.

Example 33

A composition consisting of potato starch in an amount accounting for 42.7% of the final weight of the product and pectin in an amount accounting for 0.5% of the final weight of the product and gluten in an amount accounting for 10% of the final weight of the product was continuously dosed into the hopper of the twin-screw extruder by means of screw dispensers, calcium chloride in an amount representing 0.25% of the final weight of the product, gum rosin glycerin ester in an amount representing 5% of the final weight of the product, cellulose fibers in an amount representing 20% of the final weight of the product, and sodium tetraborate in an amount representing 0.25% of the final weight of the product. On the other hand, in the first zone of the plasticizing system, located directly behind the zone of loading of loose components, liquid glycerol was continuously dosed by means of a peristaltic pump in an amount accounting for 21.3% of the final weight of the product. The extrusion process was carried out by maintaining the temperature in successive heating zones of the device in the following range of 100-165°C and a screw speed of 50 rpm. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining granulate of modified thermoplastic starch with grain diameter in the range of 3-5mm.

Table 1 shows the properties of the thermoplastic starch obtained according to Example 33.

Example 34

The method of manufacturing the rhTPS/PHI002 composition according to Example 34 is carried out in two steps. In the first stage, potato starch was mixed in a standard mechanical mixer with glycerol pectin, gluten, calcium chloride, gum rosin, cellulose fibers and sodium tetraborate, which are the raw materials for obtaining rhTPS.

The mixing process was carried out for 30 minutes at 20±5°C, with the stirrer speed in the range of 50-150 rpm. The resulting mixture was then dosed in a second stage using a screw feeder into the hopper of a co-rotating twin screw extruder. Poly (3- hydroxybutyrate-co-3-hydroxyvalerate) granules (PHI002, NaturePlast) were also dosed into the hopper via another screw feeder in an amount that made it possible to achieve a mass ratio of rhTPS to PHA in the resulting composition equal to 1/7, which corresponds to an amount of rhTPS equal to 12.5 wt.% and an amount of PHI002 equal to 87.5 wt.% on the final weight of the composition. In order to achieve the assumed mass ratios of rhTPS/PHI002, potato starch in the amount of 7.93 wt.%, glycerol in the amount of 3.97 wt.% were used to obtain rhTPS on the final mass of the rhTPS/PHI002 composition, pectin in an amount of 0.13 wt.%, gluten in an amount of 0.01 wt.%, calcium chloride in an amount of 0.01 wt.%, gum rosin in an amount of 0.31 wt.%, wood flour in an amount of 0.13 wt.%, and sodium tetraborate (borax) in an amount of 0.01 wt.%. The components dosed into the hopper were then subjected to extrusion while maintaining the extruder head temperature in the range of 165- 175°C and the temperature of the heating zones of the extruder plasticizing system in the range of 60°C to 190°C, with simultaneous degassing of the volatile parts. As a result of extrusion, an extrudate was obtained, the composition, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining rhTPS/PHI=1/7 composition granules with grain diameter in the range of 3-5mm. Table 1 shows the properties of the rhTPS/PHI002 composition obtained according to Example 34.

Example 35

The method of obtaining the rhTPS/PHI002 composition according to Example 35 is carried out in the same way, in two stages, and using the same materials, with the same mass ratio of rhTPS/PHI002 as described in Example 34 except that the content in the composition of potato starch was 6.35 wt.%, glycerol was 3.18 wt.%, pectin was 0.13 wt. %, gluten was 0.01 wt.%, calcium chloride was 0.01 wt.%, gum rosin was 0.31 wt.%, wood flour was 2.5 wt.% and borax was 0.01 wt.%. Table 1 shows the properties of the rhTPS/PHI002 composition obtained according to Example 35.

Example 36

The method of obtaining the rhTPS/PHI002 composition according to Example 36 is carried out in the same way, in two stages, and using the same materials as described in Example 34 except that the mass ratio of rhTPS/PHI002 is 7/1 , which corresponds to an amount of rhTPS equal to 87.5 wt.% and an amount of PHI002 equal to 12.5 wt.% in terms of the final weight of the composition, while the content in the composition of potato starch was 55.53 wt.%, glycerol was 27.77 wt.%, pectin was 0.86 wt.%, gluten was 0.09 wt.%, calcium chloride was 0.09 wt.%, gum rosin was 2.19 wt.%, wood flour was 0.88 wt.% and borax was 0.09 wt.%. On the other hand, PHI002 granulate was dosed into the extruder in a stream of plasticized rhTPS, in the middle of the length of the plasticization zone (L/2, L=800mm) using a side dispenser, at a rate of 12.5 wt.% per final weight of the composition. Table 1 shows the properties of the rhTPS/PHI002 composition obtained according to Example 36.

Example 37

The method of obtaining the rhTPS/PHI002 composition according to Example 37 is carried out in the same way, in two stages, and using the same materials as described in Example 34 except that the mass ratio of rhTPS/PHI002 is 7/1 , which corresponds to an amount of rhTPS equal to 87.5 wt.% and an amount of PHI002 equal to 12.5 wt.% on the final weight of the composition, while the content in the composition of potato starch was 44.45 wt.%, glycerol was 22.23 wt.%, pectin was 0.86 wt.%, gluten was 0.09 wt.%, calcium chloride was 0.09 wt.%, gum rosin was 2.19 wt.%, wood flour was 17.5 wt.% and borax was 0.09 wt.%. On the other hand, PHI002 granulate was dosed into the extruder in a stream of plasticized rhTPS, in the middle of the length of the plasticization zone (L/2, L=800mm) using a side dispenser, at a rate of 12.5 wt.% per final weight of the composition. Table 1 shows the properties of the rhTPS/PHI002 composition obtained according to Example 37.

Example 38

The method of obtaining the rhTPS/PHI002 composition according to Example 38 is carried out in one step with a mass ratio of rhTPS/PHI002 equal to 1/7.

In this method, PHI002 granulate, in an amount constituting 87.5% of the final weight of the rhTPS/PHI002 composition, was continuously dosed into the hopper of the twin-screw extruder by means of screw dispensers, potato starch in an amount constituting 8.05% of the final weight of the product and pectin in an amount constituting 0, 01 % of the final product weight, and gluten in an amount representing 0.01% of the final product weight, calcium chloride in an amount representing 0.01% of the final product weight, gum rosin in an amount representing 0.125% of the final product weight, wood flour in an amount representing 0.13% of the final product weight, and sodium tetraborate in an amount representing 0.01% of the final product weight. On the other hand, in the first zone of the plasticizing system, located directly behind the zone of loading of loose components, liquid glycerol in an amount of 4.03% of the final weight of the product and canola oil in an amount of 0.125% of the final weight of the product were dosed continuously by means of a peristaltic pump. The extrusion process was carried out by maintaining the temperature in successive heating zones of the device in the following range of 100-180°C. As a result of extrusion, an extrudate was obtained, which was cooled by forced air circulation to room temperature and subjected to granulation, thus obtaining rhTPS/PHI002 composition granules with grain diameter in the range of 3-5mm. Table 1 shows the properties of the rhTPS/PHI002 composition obtained according to Example 38.

Example 39

The method of manufacturing the rhTPS/PHI002 composition according to Example 39 is carried out in the same way, in one step, with the same mass ratio of rhTPS/PHI002 as described in Example 38 except that the content in the composition of corn starch was 6.47 wt.%, glycerol was 3.24 wt%, pectin was 0.01 wt%, gluten was 0.01 wt%, calcium chloride was 0.01 wt%, gum rosin was 0.125 wt%, olive oil was 0.125 wt%, wood flour was 2.5 wt% and borax was 0.01 wt%. Table 1 shows the properties of the rhTPS/PHI002 composition obtained according to Example 39.

Example 40

The method of obtaining the rhTPS/PHI002 composition according to Example 40 is carried out in the same way, in one step, as described in Example 38 except that the mass ratio of rhTPS/PHI002 is 7/1 , which corresponds to an amount of rhTPS equal to

87.5 wt.% and an amount of PHI002 equal to 12.5 wt.% in terms of the final mass of the composition, while the content in the composition of potato starch was 56.35 wt.%, glycerol was 28.16 wt.%, pectin was 0.09 wt.%, gluten was 0.09 wt.%, calcium chloride was 0.09 wt.%, gum rosin was 0.875 wt.%, linseed oil was 0.875 wt.%, wood flour was 0.88 wt.% and borax was 0.09 wt.%. On the other hand, PHI002 granulate was dosed into the extruder in a stream of plasticized rhTPS, in the middle of the length of the plasticization zone (L/2, L=800mm) using a side dispenser, at a rate of 12.5 wt.% per final weight of the composition. Table 1 shows the properties of the rhTPS/PHI002 composition obtained according to Example 40.

Example 41

The method of obtaining the rhTPS/PHI002 composition according to Example 41 is carried out in the same way, in one step, as described in Example 38 except that the mass ratio of rhTPS/PHI002 is 7/1 , which corresponds to an amount of rhTPS equal to

87.5 wt.% and an amount of PHI002 equal to 12.5 wt.% in terms of the final mass of the composition, while the content in the composition of potato starch was 45.27 wt.%, glycerol was 22.62 wt.%, pectin was 0.09 wt.%, gluten was 0.09 wt.%, calcium chloride was 0.09 wt.%, gum rosin was 0.875 wt.%, soybean oil was 0.875 wt.%, wood flour was

17.5 wt.% and borax was 0.09 wt.%. On the other hand, PHI002 granulate was dosed into the extruder in a stream of plasticized rhTPS, in the middle of the length of the plasticization zone (L/2, L=800mm) using a side dispenser, at a rate of 12.5 wt.% per final weight of the composition. Table 1 shows the properties of the rhTPS/PHI002 composition obtained according to Example 41.

The thermoplastic biodegradable materials obtained according to each of examples 1 to 41 were subjected to tests of their tensile strength, elongation at break according to PN- ISO 37:2007 standard, and were subjected to water wetting angle tests, and the results are shown in Table 1.

Table 1. Properties of materials obtained according to examples 1-41

The test results of the materials obtained according to examples 1-33 relating to biodegradable thermoplastic starch, shown in Table 1 , indicate that they have an ultimate tensile strength in the range of 5.5-24.0 MPa and an elongation at break in the range of 48- 457%, as well as a contact angle in the range of 31-83°. Based on them, it can be concluded that under the influence of the applied set of modifiers, there was an increase in the ultimate tensile strength of rhTPS, compared to unmodified TPS, and the greatest effect on the increase in tensile strength was due to the addition of reinforcing fillers. In contrast, the greatest effect on the increase in wetting angle, with respect to unmodified TPS, was the addition of amber dust, cork dust, and glycerin and pentaerythritol gum rosin esters to rhTPS.

As for the rhTPS/PHI compositions, a significant effect of bacterial thermoplastic polymer (PHI) on their improvement of mechanical properties is evident, while the increase in the value of their contact angle depends on the content of PHI in the composition of these materials.