RU2796732C1 - Composition for producing biodegradable polymer material and biodegradable polymer material on its basis - Google Patents

Abstract

FIELD: polymer materials.

SUBSTANCE: group of inventions: a composition for obtaining a biodegradable polymeric film material and a biodegradable polymeric film material itself. This composition contains components in the ratio, wt.%: starch - 0.8-1.2, polyvinyl alcohol - 1.1-2.5, glycerin - 3.5-5.5, acid - 0.2-0,5, ethyl alcohol - 0-8.4, chokeberry or cranberry juice - 0-1, water - the rest. The acid is selected from adipic, citric, phosphoric, oxalic, succinic acids. Biodegradable polymeric film material based on this composition contains in the ratio, wt.%: starch - 10.22–14.40, polyvinyl alcohol - 17.22–26.05, glycerin - 47.23–56.23, acid - 2.30–5.48, chokeberry or cranberry juice - 0-9.84 and water - the rest.

EFFECT: increase strength of the resulting film (increased ultimate tensile stress); reducing the time of biodegradation of the material in the soil; decrease in the degree of sorption of water vapor.

2 cl, 1 dwg, 1 tbl, 9 ex

Description

The invention relates to chemical and biochemical technology, namely, to the production of film biodegradable polymeric materials for food purposes, containing a mixture of starch with polyvinyl alcohol, used in the production of packaging thermoformed products and films capable of biodegradation under the influence of climatic factors and microorganisms. The invention can be used in biomedicine and pharmacology (disposable instruments, packaging materials, capsules), food industry (packaging material and essentials), agriculture (biodegradable films).

Known polymer composition for the manufacture of biodegradable products) [Patent 2629680 Russian Federation, IPC C08L97/00, C08L23/06, C08L23/08, C08L 97/02 Polymer composition for the manufacture of biodegradable products / Vodyakov V.N., Shabarin A.A., Shabarin A.A., Kuzmin A.M.; applicant and patent holder Federal State Budgetary Educational Institution of Higher Education "N.P. Ogarev National Research Mordovian State University" (RU). - No. 2016124877; dec. 06/21/2016; publ. 08/31/2017. Bull. No. 25], containing a biodegradable filler - beet pulp, a technological additive - polyethylene glycol, a copolymer of ethylene and vinyl acetate, a mixture of low and high pressure polyethylenes in a ratio of 1:1. The composition allows, with the same (30%) content of biodegradable filler, which provides high biodegradability, to significantly improve operational (strength up to 2 times) and technological characteristics (viscosity up to 9 times at an extrusion processing temperature of 150°C, a shear rate of 1000 s-1) . However, the introduction of beet pulp as a biodegradable filler does not allow obtaining a mass that is stable in composition, in which, in addition to the organic part, there are mineral impurities. In addition, one of the negative qualities of pulp is that fresh beet pulp contains a large amount of water, for this reason microorganisms actively develop in it and it quickly turns sour; excess water content in the pulp complicates and increases the cost of its transportation, and also requires an additional energy-intensive stage of the production process - drying.

Known food film coating [Patent 2532180 Russian Federation, IPC C08L 5/00. Biodegradable film based on pectin and chitosan / Denisova M.N., Zhuk S.G., Bukharova E.N., Rysmukhambetova G.E., Kashchenko V.F.; applicant and patent holder Federal State Budgetary Educational Institution of Higher Education "Saratov State Agrarian University named after N.I. Vavilov" (RU). - No. 2013134600/05; dec. 07/23/2013; publ. 27.10.2014 Bull. No. 30], in which the film is prepared as follows. Xanthan is dissolved in distilled water at a temperature of 27-25°C, chitosan is dissolved in a 3% citric acid solution when heated to 27-25°C. Then the resulting solutions of xanthan and chitosan, preferably in a ratio of 4:1, are drained and stirred until the resulting clots are completely dissolved. In order for the film to be strong and evenly separated from the substrate, after mixing the clots, glycerol and a 3% methylcellulose solution are added to the resulting solution. The film is formed on the substrate for 20-24 hours at a temperature of 0 to 25°C.

The disadvantages of the food film coating obtained by this method include increased moisture absorption and water solubility, as well as insufficient strength due to the high content (50-55 wt.%) of the thickener - xanthan.

The closest in technical essence and the achieved result, that is, the prototype, is a composition for obtaining a biodegradable polymeric material and a biodegradable polymeric material based on it [Patent 2669865 Russian Federation, IPC C08L 3/02, C08L 29/04, C08K 3/00, C08K 5/05, C08L 101/16. Composition for obtaining biodegradable polymeric material and biodegradable polymeric material based on it / Malinkina O.N., Papkina V.Yu., Shipovskaya A.B.; applicant and patent holder Federal State Budgetary Educational Institution of Higher Education "Saratov National Research State University named after N.G. Chernyshevsky" (RU). - No. 2017136410; dec. 10/16/2017; publ. 10/16/2018, Bull. No. 29].

The composition for obtaining a biodegradable polymeric material contains starch, polyvinyl alcohol, glycerin, water, L-aspartic acid, hydrochloric acid and ethyl alcohol in the following ratio, wt.%:

Starch 0.9-23.0 polyvinyl alcohol 1.8-23.0 Glycerol 3.5-11.2 L-aspartic acid 0.3-3.4 Hydrochloric acid 0.1-1.3 Ethanol 1.5-22.6 Water rest

Biodegradable polymeric material based on the composition containing starch, polyvinyl alcohol, glycerin, water, additionally contains the reaction product of L-aspartic and hydrochloric acids in the form of L-aspartic acid hydrochloride in the following ratio, wt.%:

Starch 24.0-40.0 polyvinyl alcohol 40.0-51.0 Glycerol 4.1-11.7 L-aspartic acid hydrochloride 7.7-9.9 Water rest

The disadvantages of the prototype are:

- insufficiently high strength of the resulting film (insufficiently high breaking stress: 0.83-2.89 MPa);

- long time of material biodegradation in soil (150 days);

- a relatively high degree of sorption of water vapor.

The technical result of the invention is

- increasing the strength of the resulting film (increase in breaking stress);

- reducing the time of biodegradation of the material in the soil;

- decrease in the degree of sorption of water vapor.

This result is achieved by the fact that the composition for obtaining a biodegradable polymeric material containing starch, polyvinyl alcohol, glycerin, water, ethyl alcohol, according to the invention, additionally contains one of the acids: adipic, citric, phosphoric, oxalic, chokeberry or cranberry juice in the following ratio of components, wt.%:

Starch 0.8-1.2 polyvinyl alcohol 1.1-2.5 Glycerol 3.5-5.5 Acid 0.2-0.5 Ethanol 0-8.4 Chokeberry or cranberry juice 0-1 Water rest

Biodegradable polymeric material based on the composition according to claim 1, containing starch, polyvinyl alcohol, glycerin, water, according to the invention, additionally contains one of the acids: adipic, citric, phosphoric, oxalic, chokeberry or cranberry juice in the following ratio, wt. %:

Starch 10.22-14.40 polyvinyl alcohol 17.22-26.05 Glycerol 47.23-56.23 Acid 2.30-5.48 Chokeberry or cranberry juice 0-9.84 Water rest

To implement the claimed invention, the following materials and reagents are used:

ГОСТ 7699-78 Крахмал картофельный. Технические условия.

GOST 7699-78 Potato starch. Specifications.

ГОСТ 32159-2013 Крахмал кукурузный. Общие технические условия

GOST 32159-2013 Corn starch. General specifications

Starch is mainly a mixture of two fractions of homoglucans (glucose polymers) of a linear and branched structure - amylose and amylopectin.

Starch is a cheap domestic raw material for large-scale production, obtained from annually renewable natural raw materials (potatoes, corn, rice, etc.), and is a biodegradable material.

ГОСТ 10779-78 Спирт поливиниловый. Технические условия.

GOST 10779-78 Polyvinyl alcohol. Specifications.

Polyvinyl alcohol is an artificial, water-soluble, thermoplastic polymer. It plasticizes in the presence of water, easily degrades under the action of enzymes, mold fungi and soil bacteria.

ГОСТ 6823-2017 Глицерин натуральный сырой. Общие технические условия. Глицерин - трехатомный спирт, один из распространенных дешевых пластификаторов полимеров, улучшает перерабатываемость и термостабильность полимерной композиции.

GOST 6823-2017 Natural raw glycerin. General specifications. Glycerin is a trihydric alcohol, one of the most common cheap plasticizers for polymers, improves the processability and thermal stability of the polymer composition.

ГОСТ 6552-80. Кислота ортофосфорная. Технические условия. Бесцветная жидкость, не имеющая запаха. Массовая доля ортофосфорной кислоты (Н₃РО₄) не менее 85-87%

GOST 6552-80. Phosphoric acid. Specifications. Colorless liquid, odorless. Mass fraction of phosphoric acid (H ₃ PO ₄ ) not less than 85-87%

ГОСТ 10558-80 Кислота адипиновая. Технические условия.

GOST 10558-80 Adipic acid. Specifications.

White crystalline substance. Mass fraction of adipic acid (C ₆ H ₁₀ O ₄ ) not less than 99.7%

ГОСТ 908-2004 Кислота лимонная моногидрат пищевая. Технические условия.

GOST 908-2004 Food grade citric acid monohydrate. Specifications.

A white, odorless crystalline substance with a strong sour taste.

ГОСТ 22180-76 Кислота щавелевая. Технические условия.

GOST 22180-76 Oxalic acid. Specifications.

Colorless crystals, soluble in water and alcohol.

ГОСТ 5962-2013 Спирт этиловый ректификованный из пищевого сырья. Технические условия.

GOST 5962-2013 Rectified ethyl alcohol from food raw materials. Specifications.

The invention is carried out as follows.

Biodegradable polymeric film material is obtained by solution technology. The solution technology provides for the production of a molding solution by mixing a prepared aqueous solution of polyvinyl alcohol, starch paste with phosphoric, oxalic, citric acid or a solution of adipic acid in ethyl alcohol, glycerin, with or without the addition of cranberry juice or chokeberry juice.

To obtain a starch paste, a weighed portion of the polymer is placed in a beaker with distilled water, in which citric, oxalic or phosphoric acid, or an alcoholic solution of adipic acid is first dissolved, and stirred in a water bath for 15-30 minutes at a temperature of 85-95°C.

To obtain a solution of polyvinyl alcohol, a portion of the polymer is dissolved in distilled water in a water bath for 20-30 minutes with stirring at a temperature of 70-80°C. The solution is then cooled to room temperature.

Adipic acid is dissolved in ethyl alcohol 95% at room temperature.

To obtain biodegradable films, a ready-made molding solution containing a mixture of starch, phosphoric, oxalic, citric or adipic acid in ethyl alcohol, glycerin and polyvinyl alcohol with or without the addition of cranberry or chokeberry juice is cast onto a glass substrate (into Petri dishes) with subsequent removal of evaporating reagents at room temperature for 3 days.

For the obtained samples of film materials, the following characteristics are determined: breaking stress, MPa, degree of water vapor sorption, %, biodegradation time, days.

The calculation of the composition of the components in the finished biodegradable material was carried out by recalculating the initial composition of the components of the molding composition (solution) taking into account the residual moisture content of the resulting material, weighing accuracy ±0.0001 g.

To determine the breaking stress of the obtained packaging materials, a 2099R-5 tensile testing machine with an active grip electric drive and an electronic force meter was used.

Breaking stress, MPa, characterizes the breaking load per unit of cross-sectional area. The speed of the tensile testing machine is set to 20 mm/min. When testing samples, the breaking load was recorded by an electronic force meter.

The sorption properties of materials with respect to water vapor were evaluated in a hermetically sealed desiccator, partially (1/20 part) filled with distilled water, at a temperature of 21±2°C and atmospheric pressure. The amount of sorbed vapors was determined gravimetrically by fixing the mass of the swollen sample on an analytical balance, the weighing accuracy was ±0.0001 g.

The study of the ability of the material to biodegradation was evaluated in vitro in a model soil environment (pH 5.0-6.0) at 21±2°C, natural light and aeration, atmospheric pressure, in humid conditions for 90 days. The prepared samples in the form of 50 × 15 mm plates were placed in a polypropylene container filled with soil. Humid conditions were created in the container by watering with a frequency of once every 3 days. Every 30 days of storage in the soil medium, the samples were removed from the container, mechanically cleaned from the soil, and the weight was determined on an analytical balance. The rate of biodegradation was judged from the weight loss of the samples.

The invention is carried out as follows.

Example 1

Stage 1 - preparation of components in the form of solutions of a given concentration, gelatinization of starch in the presence of acid.

A starch paste is prepared by mixing potato starch with distilled water (1 g of starch and 48.67 ml of distilled water at room temperature), in which oxalic acid (0.33 g) is previously dissolved, and heated at a temperature of 85 ° C and stirring for 15 minutes. Then the paste is cooled to room temperature.

To prepare a solution of polyvinyl alcohol (2.5 g of PVA and 42.5 ml of distilled water at room temperature): dry PVA is dissolved in distilled water at a temperature of 70°C with stirring for 20 minutes. After the time has elapsed, the solution is cooled to room temperature.

Stage 2 - obtaining a composition (forming solution) by mixing the components.

The forming solution is prepared by mixing starch paste (50 g) with a solution of PVA (45 g) and glycerin (5 g) at room temperature for 10 minutes.

Stage 3 - obtaining a biodegradable polymer material by casting 20 ml of the molding composition into Petri dishes with a diameter of 10 cm and drying to obtain a film at a temperature of 25 ^° C for 40 hours until a film structure is achieved. Then the film was removed from the substrate and kept for another 24 hours at a temperature of 40°C.

The appearance of the finished film modified with oxalic acid is shown in Fig. 1a.

Characteristics of the finished film modified with oxalic acid:

A thin, elastic, flexible film was obtained: it does not crack when bent; matte, poorly transmits light.

- breaking stress 3.9±0.3 MPa;

- the degree of sorption of water vapor 15.9%;

- biodegradation time 90 days.

The composition of the components in the molding solution is, wt.%:

Starch 1 polyvinyl alcohol 2.5 Glycerol 5 Oxalic acid 0.33 Water the rest (91.17)

The composition of the components in a biodegradable polymeric film material based on the composition, wt.%:

Starch 10.42 polyvinyl alcohol 26.05 Glycerol 52.10 Oxalic acid 3.43 Water rest (8)

Example 2

Stage 1 - preparation of components in the form of solutions of a given concentration, gelatinization of starch in the presence of acid.

Pre-dissolve adipic acid (0.3 g) in ethanol (8.4 ml) at room temperature for 10 minutes.

A starch paste is prepared by mixing cornstarch with distilled water (1.2 g of starch and 40.1 ml of distilled water at room temperature) to which a solution of adipic acid (0.3 g) is previously added, and heated at a temperature of 95 ° C and stirring in for 15 minutes, then the paste is cooled to room temperature.

To prepare a solution of polyvinyl alcohol (2 g of PVA and 44 ml of distilled water at room temperature): dry PVA is dissolved in distilled water at a temperature of 70°C with stirring for 20 minutes. After the time has elapsed, the solution is cooled to room temperature.

Stage 2 - obtaining a composition (forming solution) by mixing the components.

The forming solution is prepared by mixing starch paste (50 g) with a solution of PVA (46 g) and glycerin (4 g) at room temperature for 10 minutes.

Stage 3 - obtaining a biodegradable polymeric material by casting 20 ml of the molding composition into Petri dishes with a diameter of 10 cm and drying to obtain a film at a temperature of 25°C for 40 hours until a film structure is achieved. Then the film was removed from the substrate and kept for another 24 hours at a temperature of 40°C.

The appearance of the finished film modified with adipic acid is shown in Fig. 1b.

Characteristics of the finished film modified with adipic acid:

A thin, elastic, flexible film was obtained: it does not crack when bent; matte, poorly transmits light.

- breaking stress 4.2±0.5 MPa;

- the degree of sorption of water vapor 19.4%;

- biodegradation time 90 days.

The composition of the components in the molding solution is, wt.%:

Starch 1.2 polyvinyl alcohol 2 Glycerol 4 Adipic acid 0.3 Ethanol 8.4 Water the rest (84.1)

The composition of the components in a biodegradable polymeric film material based on the composition, wt.%:

Starch 14.4 polyvinyl alcohol 24 Glycerol 48 Adipic acid 3.6 Water rest (10)

Example 3

Stage 1 - preparation of components in the form of solutions of a given concentration, gelatinization of starch in the presence of acid.

A starch paste is prepared by mixing corn starch with distilled water (0.8 g of starch and 48.85 ml of distilled water at room temperature) in which succinic acid (0.35 g) is previously dissolved, and heated at a temperature of 95 ° C and stirring for 15 minutes. Then the paste is cooled to room temperature.

To prepare a solution of polyvinyl alcohol (1.1 g of PVA and 45.4 ml of distilled water at room temperature): dry PVA is dissolved in distilled water at a temperature of 70°C with stirring for 20 minutes. After the time has elapsed, the solution is cooled to room temperature.

Stage 2 - obtaining a composition (forming solution) by mixing the components.

The forming solution is prepared by mixing starch paste (50 g) with a solution of PVA (46.5 g) and glycerin (3.5 g) at room temperature for 10 minutes.

Stage 3 - obtaining a biodegradable polymeric material by casting 20 ml of the molding composition into Petri dishes with a diameter of 10 cm and drying to obtain a film at a temperature of 25°C for 40 hours until a film structure is achieved. Then the film was removed from the substrate and kept for another 24 hours at a temperature of 40°C.

The appearance of the finished film modified with succinic acid is shown in Fig. 1c.

Characteristics of the finished film modified with succinic acid:

A thin, elastic, flexible film was obtained: it does not crack when bent; matte, poorly transmits light.

- breaking stress 5.8±0.6 MPa;

- degree of sorption of water vapor 20.8%;

- biodegradation time 90 days.

The composition of the components in the molding solution is, wt.%:

Starch 0.8 polyvinyl alcohol 1.1 Glycerol 3.5 succinic acid 0.35 Water the rest (94.25)

The composition of the components in a biodegradable polymeric film material based on the composition, wt.%:

Starch 12.52 polyvinyl alcohol 17.22 Glycerol 54.78 succinic acid 5.48 Water rest (10)

Example 4

Stage 1 - preparation of components in the form of solutions of a given concentration, gelatinization of starch in the presence of acid.

A starch paste is prepared by mixing cornstarch with distilled water (1 g of starch and 48.5 ml of distilled water at room temperature) to which phosphoric acid (0.5 g) is preliminarily added, and heated at 90°C and stirring for 15 minutes . Then the paste is cooled to room temperature.

To prepare a solution of polyvinyl alcohol (2 g of PVA and 42.5 ml of distilled water at room temperature): dry PVA is dissolved in distilled water at a temperature of 70°C with stirring for 20 minutes. After the time has elapsed, the solution is cooled to room temperature.

Stage 2 - obtaining a composition (forming solution) by mixing the components.

A molding solution is prepared by mixing starch paste (50 g) with a solution of PVA (44.5 g) and glycerin (5.5 g) at room temperature for 10 minutes.

Stage 3 - obtaining a biodegradable polymeric material by casting 20 ml of the molding composition into Petri dishes with a diameter of 10 cm and drying to obtain a film at a temperature of 25°C for 40 hours until a film structure is achieved. Then the film was removed from the substrate and kept for another 24 hours at a temperature of 40°C.

The appearance of the finished film modified with phosphoric acid is shown in Fig. 1g

Characteristics of the finished film modified with phosphoric acid:

A thin, elastic, flexible film was obtained: it does not crack when bent; transparent, transmits light well.

- breaking stress 12.5±0.9 MPa;

- degree of sorption of water vapor 17.2%;

- biodegradation time 90 days.

The composition of the components in the molding solution is, wt.%:

Starch 1.0 polyvinyl alcohol 2.0 Glycerol 5.5 Orthophosphoric acid 0.5 Water rest (91)

The composition of the components in a biodegradable polymeric film material based on the composition, wt.%:

Starch 10.22 polyvinyl alcohol 20.44 Glycerol 56.23 Orthophosphoric acid 5.11 Water rest (8)

Example 5

Stage 1 - preparation of components in the form of solutions of a given concentration, gelatinization of starch in the presence of acid.

A starch paste is prepared by mixing cornstarch with distilled water (0.9 g of starch and 48.4 ml of distilled water at room temperature) in which citric acid (0.2 g) and cranberry juice (0.5 g) are previously dissolved, and heated at a temperature of 95°C and stirring for 15 minutes. Then the paste is cooled to room temperature.

To prepare a solution of polyvinyl alcohol (1.8 g of PVA and 43.7 ml of distilled water at room temperature): dry PVA is dissolved in distilled water at a temperature of 70°C with stirring for 20 minutes. After the time has elapsed, the solution is cooled to room temperature.

Stage 2 - obtaining a composition (forming solution) by mixing the components.

The forming solution is prepared by mixing starch paste (50 g) with a solution of PVA (45.5 g) and glycerin (4.5 g) at room temperature for 10 minutes.

Stage 3 - obtaining a biodegradable polymeric material by casting 20 ml of the molding composition into Petri dishes with a diameter of 10 cm and drying to obtain a film at a temperature of 25°C for 40 hours until a film structure is achieved. Then the film was removed from the substrate and kept for another 24 hours at a temperature of 40°C.

The appearance of the finished film modified with citric acid and cranberry juice is shown in Fig. 1, Mr.

Characteristics of the finished film modified with citric acid and cranberry juice:

A thin, elastic, flexible film was obtained: it does not crack when bent; matte, poorly transmits light, has a bright pink coloration.

- breaking stress 4.0±0.4 MPa;

- the degree of sorption of water vapor 24.6%;

- biodegradation time 90 days.

The composition of the components in the molding solution is, wt.%:

Starch 0.9 polyvinyl alcohol 1.8 Glycerol 4.5 Lemon acid 0.2 cranberry juice 0.5 Water the rest (92.1)

The composition of the components in a biodegradable polymeric film material based on the composition, wt.%:

Starch 10.37 polyvinyl alcohol 20.73 Glycerol 51.84 Lemon acid 2.30 cranberry juice 5.76 Water rest (9)

Example 6

Stage 1 - preparation of components in the form of solutions of a given concentration, gelatinization of starch in the presence of acid.

A starch paste is prepared by mixing potato starch with distilled water (1.1 g of starch and 47.65 ml of distilled water at room temperature) in which citric acid (0.25 g) and chokeberry juice (1 g) are first dissolved, and heated at temperature of 95°C and stirring for 15 minutes. Then the paste is cooled to room temperature.

To prepare a solution of polyvinyl alcohol (2.2 g of PVA and 43 ml of distilled water at room temperature): dry PVA is dissolved in distilled water at a temperature of 70°C with stirring for 20 minutes. After the time has elapsed, the solution is cooled to room temperature.

Stage 2 - obtaining a composition (forming solution) by mixing the components.

A molding solution is prepared by mixing starch paste (50 g) with a solution of PVA (45.2 g) and glycerin (4.8 g) at room temperature for 10 minutes.

Stage 3 - obtaining a biodegradable polymeric material by casting 20 ml of the molding composition into Petri dishes with a diameter of 10 cm and drying to obtain a film at a temperature of 25°C for 40 hours until a film structure is achieved. Then the film was removed from the substrate and kept for another 24 hours at a temperature of 40°C.

The appearance of the finished film modified with citric acid and chokeberry juice is shown in Fig. 1e.

Characteristics of the finished film modified with citric acid and chokeberry juice:

A thin, elastic, flexible film was obtained: it does not crack when bent; matte, poorly transmits light, has a bright pink coloration.

- breaking stress 4.1±0.4 MPa;

- the degree of sorption of water vapor 23.9%;

- biodegradation time 90 days.

The composition of the components in the molding solution is, wt.%:

Starch 1.1 polyvinyl alcohol 2.2 Glycerol 4.8 Lemon acid 0.25 cranberry juice 1.0 Water the rest (90.65)

The composition of the components in a biodegradable polymeric film material based on the composition, wt.%:

Starch 10.82 polyvinyl alcohol 21.65 Glycerol 47.23 Lemon acid 2.46 cranberry juice 9.84 Water rest (8)

The test results of the obtained film materials according to the prototype and according to the claimed invention are presented in the table.

Thus, from the data in the table and in the examples it follows that the proposed composition allows to obtain films based on it, characterized by a higher tensile strength (greater strength), a shorter time of biodegradation of the material (by 60 days, compared with the prototype) and a lower degree sorption of water vapor.

Table

Characteristics of the studied film samples

Sample Breaking stress, MPa Degree of water vapor sorption, % Biodegradation time, days Examples Sample #1 3.9±0.3 15.9±5.0 90 Sample #2 4.2±0.5 19.4±5.0 90 Sample #3 5.8±0.6 20.8±5.0 90 Sample #4 12.5±0.9 17.2±5.0 90 Sample #5 4.0±0.4 24.6±5.0 90 Sample #6 4.1±0.4 23.9±5.0 90 Prototype Sample #1 0.83±0.2 16±5.0 150 Sample #2 2.82±0.5 24.0±5.0 150 Sample #3 2.89±0.3 53.0±5.0 150

Claims (4)

1. A composition for obtaining a biodegradable polymeric film material containing starch, polyvinyl alcohol, glycerin, water, ethyl alcohol, characterized in that it additionally contains one of the acids: adipic, citric, phosphoric, oxalic, succinic, chokeberry or cranberry juice when the following ratio of components, wt.%: Starch 0.8–1.2 polyvinyl alcohol 1.1–2.5 Glycerol 3.5–5.5 Acid 0.2–0.5 Ethanol 0–8.4 Chokeberry or cranberry juice 0–1 Water rest 2. Biodegradable polymeric film material based on the composition according to claim 1, containing starch, polyvinyl alcohol, glycerin, water, characterized in that it additionally contains one of the acids: adipic, citric, phosphoric, oxalic, chokeberry or cranberry juice in the following ratio of components, wt.%: Starch 10.22–14.40 polyvinyl alcohol 17.22–26.05 Glycerol 47.23–56.23 Acid 2.30–5.48 Chokeberry or cranberry juice 0–9.84 Water rest

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