RU2725039C1 - Biodegradable dishware production method - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: invention relates to disposable utensils and packing materials which are completely decomposed in natural conditions without causing harm to environment and method of its production. Method of biodegradable dishware production from mixture of components, by molding said mixture in mold at heating and under pressure, characterized by that for mixture using powdered composition of grain extraction cake with particle size from 0.2 to 3.00 mm in amount of (95–98) wt%, having moisture content of not more than 9 %, and ground biodegradable film in amount of (2–5) wt%, the latter consists of the following components, wt%: potato starch – (4.2–5.0), sodium alginate – (0.1–0.8), glycerol – (5.0–20.0), distilled water – the rest; to obtain film said components are thoroughly mixed, treated with ultrasound, heated in water bath to temperature (80–90) °C is cooled to temperature of 50 °C, film is formed by irrigation on glass surface and dried at temperature (20–25) °C, then obtained film is ground to particles size of 0.01 to 3.20 mm; powdered composition of grain cake and biodegradable film is leveled in lower part of metal mold consisting of two parts by vibration during (0.2–0.5) min, then mold is covered with its upper part, creating pressure by means of connection with press (20–60) tons, at temperature (120–160) °C, then, mold is opened, pressure is reduced to atmospheric pressure and ready dishware is removed.EFFECT: technical result consists in developing a method of producing biodegradable molded dishware, having sufficient strength characteristics, biodegradability at given conditions without damage to environment.1 cl, 3 tbl

Description

The present invention relates to disposable tableware and packaging materials, completely decomposable in natural conditions, without harming the environment and the method of its production. More specifically, the invention relates to disposable tableware that does not contain synthetic polymers resistant to aggressive environments, thus, determining the ability of the product to undergo biodegradation under environmental conditions during composting.

Known methods for producing a composite biodegradable molded tableware from plant materials that are used in industrial enterprises involve the use of wheat straw, bran, compositions from harvest residues, composite mixtures from plant materials containing a synthetic polymer. Such methods make it possible to obtain products of limited applicability, with low performance, low biodegradability due to the presence of synthetic components in the composition.

A known method of producing self-decomposable disposable tableware and method of its production (patent for invention 2309652, "Self-decomposable disposable tableware and method of production", IPC A47G 19/03, B65D 65/46, C08L 97/02, publ. 10.11.2007). This method of producing disposable tableware includes fine grinding and mixing of crop residues, corn flour, paper mulberry bark, moss, a mixture of flour from grain crops at an established mass. % ratio of components. Forming the mixture into products of a given shape and size is carried out at a temperature of 140-150 ° C, using a 500-ton hydraulic press.

The disadvantage of this method is the complexity of the manufacturing process of the product, the selection of raw components, the difficulty of maintaining a bonding ability with the ratio of components, slight deviations from the established requirements adversely affect the deformation and mechanical properties, increases the biodegradation time.

A known method of producing biodegradable molded products, in particular tableware and packaging (patent for invention EP 027907 B1, IPC D21J 1/00, D21J 3/00, publ. 09/29/2017). This method of obtaining biodegradable molded products involves the use of water vapor pressure inside the composite form for mixing granular components with a granule size of from 0.01 to 2.80 mm in an amount of 95-100 wt. % containing more than 14 wt. % water. Placement of the prepared mixture in a special form, closing the form and subsequent simultaneous exposure of the mixture to a temperature of 120 ° C or higher and a pressure of 1 to 10 MPa.

The disadvantage of this method is the difficulty of controlling the process, in particular, the intensity of the flow of water vapor and temperature, and the deviation of these parameters leads to rupture of the molded products.

The technical task of the invention is the development of a method for the production of composite biodegradable molded glassware from a powder composition consisting of crushed grain meal and a biodegradable composite film having sufficient strength characteristics, biodegradability under given conditions without harming the environment.

The technical problem is solved due to the fact that the method for the production of biodegradable utensils from a mixture of components, by molding the specified mixture in a mold when heated and under pressure, is characterized in that, according to the invention, a powdery composition of grain meal with a particle size of from 0 is used for the mixture , 2 to 3.00 mm in the amount of (95-98) wt. %, having a moisture content of not more than 9%, and a crushed biodegradable film in an amount of (2-5) wt. %, the latter consists of the following components, mass. %: potato starch - (4.2-5.0), sodium alginate - (0.1-0.8), glycerin - (5.0-20.0), distilled water - the rest; to obtain a film, these components are thoroughly mixed, treated with ultrasound, heated in a water bath to a temperature of (80-90) ° С, cooled to a temperature of 50 ° С, the film is formed by watering on a glass surface and dried at a temperature (20-25) ° C, then the resulting film is crushed to a particle size of 0.01 to 3.20 mm; the powder composition of grain meal and a biodegradable film is leveled at the bottom of a two-part metal mold by vibration for (0.2-0.5) minutes, then the mold is covered with its upper part, created with using the connection with the press, the pressure is (20-60) tons, at a temperature of (120-160) ° С, then the mold is slightly opened, the pressure is reduced to atmospheric and the cookware is removed.

The proposed method includes placing a predetermined amount of the specified initial powder composition (mixture) in the lower part, consisting of two parts, a metal mold for making dishes, leveling it with vibration for 0.2-0.5 minutes at the bottom of this mold. Then the lower part of the mold is covered with the upper one to form a gap between the edges of the mold 0.3-0.5 mm, heated to a temperature of 120-160 ° C and a pressure of 20-60 tons is applied using a hydraulic press, then the pressure is relieved. The form is opened and the finished dishes are removed.

To obtain biodegradable utensils, a mixture is used, including powder compositions, consisting of grain meal with a particle size of 0.2 to 3.00 mm in an amount of 95-98 wt. %, humidity not more than 9% and crushed biodegradable composite film, in an amount of not more than 2-5 wt. %, consisting of the components of the mixture, mass. %: potato starch - (4.2-5.0), sodium alginate - (0.1-0.8), glycerin - (5.0-20.0), distilled water - the rest; followed by grinding the dried film to a particle size of 0.01 to 3.20 mm

The use of the mixture in this percentage (grain meal in the amount of 95-98 wt.% And crushed biodegradable composite film 2-5 wt.%), Allows you to get plates with a diameter of 10-30 cm with well-formed raised edges. Samples of dishes have a flat, dense, impact-resistant, slightly rough surface that does not change their properties when in contact with food.

An essential distinguishing feature of the claimed invention is that for the production of biodegradable dishes, a mixture of components is used, which consists of food waste (grain meal) with a particle size of 0.02 to 3.00 mm in an amount of 95 - 98 wt. %, humidity not more than 9% and crushed biodegradable composite film, in an amount of not more than 2-5 wt. %, i.e. in general, the starting mixture does not contain synthetic materials.

To obtain a biodegradable composite film, stirring is first carried out with a mechanical stirrer at a speed of 120 rpm for 5 minutes, a mixture of starch and sodium alginate, taken in a ratio of 5: 1, dissolved in distilled water, 1-5 parts of glycerol are added at the end of the mixing process . The resulting suspension is treated with ultrasonic treatment (UZV) on the Volna device, model UZTA-0.63 / 22-OM, at a frequency of 22 ± 1.65 kHz and an exposure power of 630 W for 5 minutes in a cooling system at a temperature of (28 ± 4 ) ° C. The solution obtained after exposure to ultrasonic testing is heated in a water bath with stirring and at a temperature of (80-90) ° С and the solution is cooled to a temperature of 50 ° С. Films are formed using the method of watering on a glass surface with subsequent distribution of the solution over the surface, dried at a temperature of (20-25) ° C. An ice bath is used as a cooling system, where a container with the solution to be treated is placed, and the temperature (28 ± 4) ° С is controlled by a thermometer placed in the liquid to be treated.

Grain meal is a peeling product of cereal crops containing fruit and seed shells, as well as the aleurone layer, formed as a by-product in the production of flour, cereals and other types of food products.

Biodegradable composite material (film) based on plant biopolymers obtained in the following ratio of components, wt. %:

potato starch 4.2-5.0

sodium alginate 0.1-0.8

glycerol 5.0-20.0

distilled water - the rest.

Starch is a mixture of polysaccharides (amylose and amylopectin), the monomer of which is alpha glucose. Starch is synthesized by different parts of plants in chloroplasts and varies in different proportions. Potato - 24%, rice - 75%, corn - 70%, wheat - 64% starch are sources of starch. Potato starch is one of the most common polysaccharides used as a stabilizer and thickener in food production. Potato starch has a high degree of swelling and a low gelation temperature. The physicomechanical properties of films based on potato starch depend on the ratio of crystalline and amorphous forms [3].

Glycerin (1,2,3-propanetriol) is responsible for the plasticity and flexibility of the films. With its deficiency, the films do not stretch, they easily break when bent. With an excess of glycerol, films poorly separate from the surface, become sticky, viscous.

To improve the quality of films based on potato starch, film-forming substances (sodium alginate) are additionally added. Sodium alginate is a water-soluble salt of alginic acid found in all types of brown algae. It has enhanced film-forming properties due to its unique colloidal properties, which include the stabilization of emulsions, the formation of suspensions and gelation, thus being widely used in the food industry [2, 4].

The grain size distribution of grain meal (table 1) should have a particle size of 0.2 to 3.00 mm, which ensures maximum adhesion of the material. For grinding, a mill LZM-1M is used. In the presence of larger particles, the surface of the dish loses homogeneity, acquires increased roughness, and separate stratified areas stand out. The presence of only a small particle size leads to a loss of strength characteristics and impact resistance of dishes when dropped.

The moisture content of the grain meal should be no more than 9%, the maximum reduction in humidity is preferable, but for this, as a rule, additional equipment and energy consumption are necessary, which is not cost-effective from the point of view of economic development efficiency. The use of grain meal moisture content of more than 9% leads to an uneven surface of the product due to a sharp transition of moisture contained in the raw material into a vapor state during pressing of products at elevated temperature and pressure.

The use of the heating temperature of the mixture in the mold before pressing within (120-160) ° C is due to the fact that lower values (less than 120 ° C) do not allow the crushed biodegradable composite film used in the mixture to melt, which sharply reduces the strength characteristics of the products . While the temperature above 160 ° C leads to the burning of the surface of the molded products.

The conditions for obtaining biodegradable composite material are due to the following factors:

Using these modes of mixing a mixture of starch and sodium alginate (120 rpm for 5 minutes) allows you to get the most homogeneous structure of the suspension, and in the future, the film. A lower intensity and duration of exposure leads to the formation of compacted clots, a non-uniform film structure, reduces its elasticity and strength characteristics. The high intensity and duration of exposure is impractical from an economic point of view.

It is also significant that the solution be treated with ultrasonic action (ultrasound) with a power of 630 W, at a frequency of (22 ± 1.65) kHz for 5 minutes in a cooling system at a temperature of (28 ± 4 ° C). It is known that cavitation disintegration of food media is caused by the pressure reached on the surface of the bubbles when they are compressed to a minimum volume relative to the rest state (collapse). Due to the ultrasonic treatment, structural changes occur in the matrix of the composite. Ultrasonic ultrasound promotes the preparation of homogeneous suspensions of the film solution and accelerates the crosslinking of components [1, 5].

The applied exposure power (630 W) is due to the maximum technical characteristics of the device, and the exposure duration (5 minutes in the cooling system (28 ± 4) ° С) allows to obtain the lowest viscosity of solutions (142.8 ± 25) mPa * s and to form thin irrigation method , homogeneous in composition, elastic film, well crushed to a given particle size distribution.

The specified range of heating temperature ((80-90) ° С) and its duration (no more than 5 minutes) are determined by the selection of optimal parameters for the technological operation — crystallization of starch (gelation process), with less temperature and time exposure, gelation does not occur, and with a greater impact - excessive dilution of the system is observed, which reduces the strength characteristics of the films.

The granulometric composition of the biodegradable composite material (table 2) to a particle size of 0.01-3.20 mm (when using the LZM-1M mill) is necessary for its uniform distribution in the composition of the mixture, the presence of a larger particle size significantly complicates this process, and grinding it to the minimum characteristics it is not advisable from an economic point of view and leads to significant losses during mechanical mixing of the mixture as a result of settling on the walls of the tank.

Example.

A mixture of grain meal with a particle size of 0.2 to 3.00 mm and a moisture content of not more than 9% in an amount of 95-98 wt. % and crushed biodegradable composite film based on natural biopolymers with a particle size of 0.01 to 3.20 mm in an amount of 2-5 wt. % thoroughly mixed until a homogeneous composition. Then the mixture is placed in the lower part of the metal mold, level the mixture with vibration and formed after closing the upper part of the metal mold with the formation of a gap between the edges of the mold 0.3-0.5 mm, connected to the hydraulic press, with a pressure of 20-60 tons, at a temperature 120-160 ° C. Then the pressure is released, the mold is opened and the molded utensils are removed.

The following ratios of components were used to obtain biodegradable utensils:

Sample 1 - a mixture of grain meal: crushed biodegradable composite film in a ratio of 98: 2.

Sample 2 - a mixture of grain meal: crushed biodegradable composite film in a ratio of 97: 3.

Sample 3 - a mixture of grain meal: crushed biodegradable composite film in a ratio of 96: 4,

Sample 4 - a mixture of grain meal: crushed biodegradable composite film in a ratio of 95: 5.

Based on the results presented in table 3, we can conclude that the obtained biodegradable utensils have good stiffness indicators, and with the introduction of more crushed biodegradable composite film, this characteristic increases. But when the ratio of grain meal: crushed biodegradable composite film 95: 5, the appearance of pronounced surface defects (ribbing, swelling of individual surfaces and etc.) is observed, on the basis of this fact 3 and 4 were selected as optimal samples.

Crockery is able to completely disintegrate into individual structural elements. The specified material for making dishes may serve as material for the development of compost. In determining the degree of development of molds on the material, it was found that it contains a sufficient amount of nutrients conducive to the development of fungi.

In addition, the composition of the proposed tableware lacks synthetic materials and it can be concluded that the tableware made according to the proposed method for self-biodegradation under the influence of natural factors.

List of references

1. Bezzubov, A.D. Ultrasound and its application in the food industry / A.D. Bezzubov, E.I. Garlinskaya, V.M. Friedman. - Moscow: Publisher: Food Industry, 1964. - 196 p.

2. Zakirova, A.Sh. The effect of enzymatic processing of potato starch on the physicomechanical properties of biofilms / A.Sh. Zakirova, T.N. Manakhova, A.V. Canary, Z.A. Canary // Bulletin of Kazan Technological University. - 2013. - T. 16. - No. 6. - S. 117-120.

3. Krutko, E.T. Technology of biodegradable polymeric materials / E.T. Krutko, N.R. Prokopchuk, A.I. Globa. - Minsk: Publisher: BSTU, 2014. - 105 p.

4. Borcharda, W. Phase diagram of the system sodium alginate / water: A model for biofilms / W. Borcharda, A. Kenninga, A. Kappa, C. Mayerb // International Journal of Biological Macromolecules - 2005. - V. 35 . - No. 5. - P. 247-256.

5. Usachev Ivan. Usage of thermoplastic starch and ultrasound in development of biodegradable polymer film / Ivan Usachev, Alexander Papahin, Valentina Kolpakova, Nikolay Lukin, Vladimir Ananiev // Proceedings of the International Multidisciplinary Scientific Ge-oConference SGEM. - 2018. - V. 18. - P. 1019-1025.

Claims (1)

A method for the production of biodegradable utensils from a mixture of components by molding the mixture in a mold under heating and pressure, and for the mixture using a powdered composition of grain meal with a particle size of from 0.2 to 3.00 mm in an amount of (95-98) wt. %, having a moisture content of not more than 9%, and a crushed biodegradable film in an amount of (2-5) wt.%, the latter consists of the following components, wt.%: potato starch - (4.2-5.0), sodium alginate - (0.1-0.8), glycerin - (5.0-20.0), distilled water - the rest; to obtain a film, these components are thoroughly mixed, sonicated, heated in a water bath to a temperature of (80-90) ° С, cooled to a temperature of 50 ° С, the film is formed by watering on a glass surface and dried at a temperature (20-25) ° C, then the resulting film is crushed to a particle size of 0.01 to 3.20 mm; the powder composition of grain meal and a biodegradable film is leveled at the bottom of a two-part metal mold by vibration for (0.2-0.5) minutes, then the mold is covered with its upper part, created using a compound with the press, the pressure is (20-60) tons, at a temperature of (120-160) ° С, then the mold is slightly opened, the pressure is reduced to atmospheric and the cookware is removed.