WO2021173019A1

WO2021173019A1 - Biodegradable material for forming disposable tableware and packaging and the method of obtaining thereof

Info

Publication number: WO2021173019A1
Application number: PCT/PL2021/000010
Authority: WO
Inventors: Adam EKIELSKI; Tomasz ZELAZINSKI; Patryk STASIAK
Original assignee: Szkola Glowna Gospodarstwa Wiejskiego W Warszawie
Priority date: 2020-02-25
Filing date: 2021-02-24
Publication date: 2021-09-02
Also published as: PL433049A1

Abstract

The subject of the present invention is a biodegradable material for the manufacture of disposable tableware and packaging containing extruded apple pomace and beet pulp and starch, as well as a method of manufacturing biodegradable apple pomace or beet pulp material for forming said products.

Description

Biodegradable material for forming disposable tableware and packaging and the method of obtaining thereof

The subject of the present invention is a biodegradable material for forming disposable tableware and packaging.

The main areas of mass production of disposable tableware are plastic or paper plates. The main disadvantage of plastic plates is a very long decomposition time, counted in hundreds of years, and a large environmental burden both at the production stage and after being used by the consumer. A significant disadvantage of paper plates is their lack of water resistance. There is a practice of covering paper plates with foil film, which increases their water resistance, however, in such case the plate loses its biodegradable properties after use and, similarly to a plastic plate, its decomposition time is counted in hundreds of years.

In the last few years, significant progress has been made in the field of the production of biodegradable materials, in particular intended for disposable packaging, the waste of which constitutes the largest share of the global mass of municipal waste. The market of raw materials for their production is rapidly growing, mainly including starch, which is a cheap and easily available renewable raw material suitable for thermoplastic processing. One of the research areas is thermoplastic starch (TPS). Currently, TPS coatings are manufactured mainly with the use of extrusion technology. The obtained coatings are single-layer materials.

From the Polish patent PL171872, a material containing 30-85% by weight of biodegradable synthetic material based on a polysaccharide is known, and as a biodegradable additive, this material contains 15-70% by weight of starch or unmodified cellulose and additional components. This material is obtained by melting a polysaccharide at elevated temperature, followed by adding starch or cellulose. The mixture is initially a starch dispersion with a water content of, at most, 25% or a cellulose dispersion in a melted polysaccharide material. This mixture is granulated and then the pellets are formed. This technology is complex and multi-stage.

The Polish patent PL230037 describes a material for manufacturing of biodegradable fittings, in particular cutlery, which is a polylactide composite containing grain mill products and possibly up to 10% by weight of a mixture of flavours and/or fragrances and/or colouring additives and/or an agent with anti blocking and brightening properties and/or an impact resistance modifying agent of the material, characterized in that it consists of a basic polylactide mixed with 0.01% to 50% by weight of loose bran, in particular wheat bran, which is a selected bran fraction of from 0.01 mm to 2.80 mm containing from 0.01 % to 7% of structurally bound water in the form of moisture or mixed with bran, in particular wheat bran, pellets with a pellet size of from 0.1 mm to 10 mm, containing from 0.01% to 7% of structurally bound water in the form of moisture.

From the Polish patent description PL174592 an ecological material of biological origin for the production of disposable tableware and packaging and the method of manufacturing products from this material are known. The dry material contains grain milling products in the amount of 50-95% by weight of dry matter, milling products of potatoes, soybeans and other plants in the amount of 0-90% by weight of dry matter and as a binder animal protein in the amount of up to 30% by weight of dry matter, as well as flavour and fragrance additives, preservatives and dyes. The material according to the invention, after mixing and kneading with water, is extruded to a dough consistency and then baked using traditional methods for between ten and twenty minutes.

From the patent description PL195130 a material for the production of biodegradable fittings, in particular tableware and packaging, is known, consisting of 95-100% by weight of loose bran, in particular wheat bran, which is a selected bran fraction with a grain size of from 0.01 to 2.80 mm, containing from 7% to 45% of structurally bound water in the form of moisture, and optionally up to 5% by weight of the mixture of waterproofing components and/or flavour and/or fragrance and/or non-fibrous additives.

From the German patent application DE202018004337 an edible straw formed from a biological material containing at least 17% by weight of cereal grain gluten, 55-80% cereal grain starch and apple fiber is known.

Until now, attempts have been made to extrude disposable tableware from a material with the addition of bran by known methods. The products manufactured in this way, however, were very brittle.

The object of the present invention is to develop biodegradable materials for commercial applications, in particular for manufacturing of disposable tableware and packaging, which are free of the drawbacks of the prior art.

It has surprisingly been found that it is possible to form tableware from biological waste, such as apple pomace and beet pulp. Surprisingly, it turned out that a material with optimal composition and properties is obtained when the content of biological waste is as high as possible.

The subject of the present invention is a biodegradable material for forming disposable tableware and packaging containing extruded apple pomace containing from 5% to 20% water or beet pulp containing from 5% to 15% water and thermoplastic starch.

Preferably, the biodegradable material for forming disposable tableware and packaging comprises up to 95% by weight of extruded apple pomace and a thermoplastic starch in an amount of 5 to 20% of the total weight.

Preferably, the biodegradable material for forming disposable tableware and packaging comprises up to 95% by weight of extruded beet pulp and a thermoplastic starch in an amount of from 5 to 50% of the total weight.

Preferably, the apple pomace and beet pulp constitute a selected fraction with a size of from 2 mm to 10 mm.

Preferably, the composition further comprises 2 to 10% by weight of microcellulose, 1 -5% of talc, 0.5-1% of chitosan and/or up to 5% by weight of a mixture of flavours and/or fragrances and/or colouring additives.

Preferably, the final moisture content of the formulated mixtures is in the range of 5-20% water.

The next subject of the invention is a method for manufacturing of a biodegradable material from apple pomace or beet pulp, characterized in that: a) excess water is removed from the material of apple pomace or beet pulp through their pressure and thermal treatment in the extrusion process at a temperature of 100-140°C, while water in the form of water vapour from the extruded material is gradually removed during the process through venting ports, wherein the material is compressed and heated each time upstream the port, b) after leaving the extruder, the material expands rapidly, the water contained in the material is evaporated, and the excess pressure in the extruder is rapidly equalized with the atmospheric pressure, c) the material thus obtained is dried to a moisture content of 10-14%.

Preferably, the material obtained in steps b) and c) is mixed with starch and pressed to form disposable tableware and packaging.

Preferably, removal of excess water from the material in step a) is carried out in an extruder (6).

Preferably, removal of excess water from the material is conducted until the material moisture reaches 60% by weight.

Preferably, the length of the compression zone in step a) is 4D of the extruder cylinder diameter.

Preferably, the temperature of the material extrusion process is 100-120°C (T1 ), and then the material is exposed to temperatures of 120-140°C (T2) and 110-200°C (T3).

Preferably, the process temperature in step b) is from 110 to 140°C and the pressure in the expanding head of the extruder is 5-20 MPa.

Preferably, during the extrusion, the material is heated by friction and heating elements located on the extruder housing (6).

Preferably, the extrusion of the material is carried out under an overpressure of 0.5-5 MPa upstream the venting ports.

Preferably, the instantaneous or maximum pressure in the extruder cylinder does not exceed 25 MPa at any step of the extrusion process.

Preferably, the pressure created is reduced and the water is evaporated as the material enters the venting port (3, 4).

Preferably, the resulting overpressure is reduced by using a vacuum fan (1 , 2).

Preferably, the pomace and pulp after the extrusion process are dried to a moisture content of 14%.

Preferably, the material is dried on a belt dryer.

The material for forming disposable tableware and packaging contains extruded apple pomace (apple pomace is a selected fraction thereof with dimensions from 2 mm to 10 mm, containing 5% to 20% water) with the addition of thermoplastic starch in the amount of 5 to 20% of the total weight. The apple pomace used in the mixture is waste from the agro-food sector. To improve the quality parameters of the above-mentioned mixture, various improvers can be used, e.g. microcellulose (2-10%), talc (1 -5%), chitosan (0.5-1%) and optionally up to 5% by weight of the mixture of flavours and/or fragrances and/or colouring additives. The final moisture content of the formulated mixtures should be in the range of 5-20% of water. In the process of preparing the raw material, the ingredients should be mixed using commonly used mixers (e.g. ribbon) for 10-15 minutes, until a homogeneous mixture is obtained. All ingredients should be added at the same time.

The material for forming disposable tableware and packaging contains extruded beet pulp (the pulp is a selected fraction with dimensions from 2 mm to 10 mm, containing from 5% to 15% water) with the addition of thermoplastic starch in the amount of 5% to 50%. The pulp used in the mixture is waste from the agro-food sector. In order to improve the quality parameters of the above-mentioned raw material, various improvers can be used, e.g. 1 -5% talc, up to 5% of mixtures of flavours and/or fragrances and/or colouring additives. The final moisture content of the formulated mixtures should be in the range of 5-15% of water. In the process of preparing the raw material, the ingredients should be mixed using commonly used mixers (e.g. ribbon) for 10-15 minutes, until a homogeneous mixture is obtained. All ingredients should be added at the same time.

The process of manufacturing the material according to the present invention consists of the appropriate preparation of the waste material and mixing it in an appropriate proportion with thermoplastic starch (TPS). Then the material is pressed and formed in conditions of high humidity and temperature close to the material flow temperature. Under these conditions, there is a surface diffusion between the individual components, and therefore their permanent bonding occurs. In the process of combining the components, no binder other than the native material and plasticizer is used. This process can be compared to that of metal welding. It is possible to obtain TPS coatings with different barrier and strength properties.

The manufacturing line for manufacturing a semi-finished product from wet apple pomace or beet pulp is shown in Fig. 1 . The purpose of the process is to change the internal structure of the pomace, reduce its moisture content and reduce microbiological contamination. Apple pomace constitutes up to 20% of residues from apple processing for consumption purposes. Unprocessed apple pomace and beet pulp decompose quickly, which is why they should be processed immediately after production. Wet apple pomace or beet pulp with a moisture content of about 60% require intensive drying to the moisture content of 14%. Since manufacturing of the material for disposable plates, apart from drying, also requires homogenization of the material, a twin-screw extruder with L:D, 25-30 (L- length, D- screw diameter) can be used for the process.

Wet pomace is fed to the extruder input. In the first step of the process, the pomace is compressed and excess water is removed through the openings in the extruder housing. In the initial length from the material feeding point, the extruder acts as a press. Thanks to the operation of the press, it is possible to remove excess water and obtain a humidity of 60% by weight. The length of the pressing zone is: 4D (extruder cylinder diameter). At a later stage, the pomace is moved to the high-temperature zone by means of extruder screws. During extrusion, the material is intensively heated by friction and heating elements located on the extruder housing. As the material is moved inside the extruder cylinder, the material is heated to a temperature above the boiling point of water. Due to the overpressure acting on the material (0.5-5 MPa), it is possible to keep water in the material in the liquid phase. When reaching the venting port, the material pressure is lowered and the water is rapidly evaporated. The pressure is reduced by a vacuum fan, which intensifies the water evaporation rate. The material pushed by the freshly fed pomace is moved to the next compression section of the extruder, where the pomace is again compressed and heated, and at the end of the heating section there is another venting port. The extruder ends with a head equipped with output openings with a diameter of 2-3 mm. In the next part of the technological line there is a belt dryer which dries the material to a humidity of 10-14%.

The added value of using the extruder is the reduction of biological contamination in the raw material. It should be noted that the use of low-processed waste materials facilitates the introduction of the material into the natural cycle existing in nature: solar energy-plant-product-fertilizer. The material for biocomposites according to the invention significantly reduces the need to use energy from external sources for the production of disposable tableware, which are used in the production of plastic tableware. All raw materials used for production are fully biodegradable. The technologies used in the processing of raw materials do not reduce the biodegradation rate of the final product. Introducing the manufacture of products from low-processed raw materials reduces the impact of the production on the environment. Description of the Drawings

Fig. 1 shows the technological line for extrusion of apple pomace and beet pulp in a twin-screw extruder.

The invention is illustrated in non-limiting embodiments.

Example 1

The raw material composition (percentage by weight) of mixtures for the production of disposable plates with the additives used (final moisture content in the mixtures: 13-14%) is presented below. a) extruded apple pomace - 82%, thermoplastic starch 18%. b) extruded apple pomace - 78%, thermoplastic starch - 19%, talc - 3%. c) extruded apple pomace - 75%, thermoplastic starch - 15%, microcellulose - 5%, talc - 2%, chitosan - 0.5%, colouring additives - 2.5%. d) extruded apple pomace - 83%, thermoplastic starch - 10%, microcellulose - 2%, talc - 2%, chitosan - 0.5%, colouring additives - 2.5%. e) extruded apple pomace - 80%, thermoplastic starch - 5%, microcellulose - 7%, talc - 4%, chitosan - 1%, colouring additives - 3%.

In the process of preparing the raw material, the ingredients should be mixed using commonly used mixers (e.g. ribbon) for 10-15 minutes, until a homogeneous mixture is obtained. All ingredients should be added at the same time.

Example 2

The raw material composition (percentage by weight) of mixtures for the production of disposable plates with the additives used (final moisture content in the mixtures: 13-14%) is presented below. a) extruded beet pulp - 90%, thermoplastic starch - 10%. b) extruded beet pulp - 90%, thermoplastic starch - 9%, talc - 1%. c) extruded beet pulp - 65%, thermoplastic starch - 33%, talc - 2%. d) extruded beet pulp - 50%, thermoplastic starch - 44%, talc - 3%, colouring agents - 3%.

Example 3

In the first step of the process, the extruder acts as a press, where the pomace is compressed and excess water is removed through the openings (6) in the extruder housing. This zone is located between the extruder feed and the first compression system (7), the length of this zone is 4D of the extruder cylinder diameter. Thanks to this, it is possible to remove excess water and obtain a moisture content of the raw material of approx. 40%.

At a further step, the material is transferred to the zone with a temperature of 100-120°C (T1 ) by means of extruder screws (8). The temperature of the extrusion process from this point is regulated by means of the extruder heaters (11 ) mounted on the extruder cylinder. At the end of the zone, at a distance of ½ from the extruder inlet, there is a compression system (9) and a first venting port (3). In the next zone of the extruder, a dense coil screw (10) and two heaters are used to maintain the temperature in the range of 120-140°C (T2) and 110-200°C (T3). At the end of this zone, the extruder screw compression system (11 ) and the second venting port (4) are also used. Upstream the venting ports (9, 11 ), the transported material is compressed to a pressure of 0.5-5 MPa, and next, there is a decrease in material pressure and rapid evaporation of water, which is additionally intensified by fans (1 , 2) generating negative pressure at the level of p=0.001 -0.002 MPa.

In the last step of the extrusion process, the material is directed to the next section of dense coil screws (13), where the process temperature ranges from 110 to 140°C (T4, T5), and the pressure is 5-20 MPa (instantaneous or maximum pressure in the extruder cylinder should not exceed 25 MP at any step of the extrusion process). The material leaves the extruder through the openings in the extruder head (openings 2-3 mm in diameter), expanding and intensively releasing water vapour. The output material is cut with a knife cutter (14) mounted at the exit of the extruder head. Moisture drop of the obtained material is Aw = 30-45% immediately after exiting the extruder.

The material obtained in the above-mentioned process (extruded pomace or beet pulp) can be dried, crushed, screened and mixed with thermoplastic starch and additional ingredients (e.g. microcellulose, talc, chitosan, flavour/fragrance/colouring additives) using commonly used technological equipment. If necessary, the resulting mixtures can also be moistened (with water or steam), e.g. in the step of mixing the components.

The obtained material/mixtures can be used to produce biodegradable disposable plates using commonly used methods of pressure forming products, e.g. with the use of presses.

Reference numerals

1 , 2 - vacuum fan, (p = 0.001 - 0.002 MPa).

3, 4 - venting port

5 - expanding head outlet (p = 5-20MPa)

6 - preliminary moisture drainage opening

7 - compression system (disc, ring, reverse flow screws)

8 - extruder screw

9, 11 - compression system (disc, reverse flow screws)

10, 13 - extruder screw (dense coil)

12 - extruder heaters 14 - cutter knife

T1 - T5 - Heater temperature settings: T1 =100-120°C; T2=120-140°C; T3=110-200°C; T4=110- 140°C; T5=110-140°C.

Claims

1. A biodegradable material for forming disposable tableware and packaging comprising extruded apple pomace containing from 5% to 20% water or beet pulp containing from 5% to 15% water and thermoplastic starch.

2. A biodegradable material for forming disposable tableware and packaging according to claim 1 , characterized in that it comprises up to 95% by weight of extruded apple pomace and a thermoplastic starch in an amount of 5 to 20% of the total weight.

3. A biodegradable material for forming disposable tableware and packaging according to claim 1 , characterized in that it comprises up to 95% by weight of extruded beet pulp and a thermoplastic starch in an amount of from 5 to 50% of the total weight.

4. The biodegradable material according to claim 1 , characterized in that the apple pomace and beet pulp constitute a selected fraction with a size of from 2 mm to 10 mm.

5. The biodegradable material according to claim 1 , characterized in that the composition further comprises 2 to 10% by weight of microcellulose, 1 -5% of talc, 0.5-1% of chitosan and/or up to 5% by weight of a mixture of flavours and/or fragrances and/or colouring additives.

6. The biodegradable material according to claim 1 , characterized in that the final moisture content of the formulated mixtures is in the range of 5-20% water.

7. A method for manufacturing of biodegradable material from apple pomace or beet pulp for forming disposable tableware, characterized in that a) excess water is removed from the material of apple pomace or beet pulp through their pressure and thermal treatment in the extrusion process at a temperature of 100-140°C, while water in the form of water vapour from the extruded material is gradually removed during the process through venting ports, wherein the material is compressed and heated each time upstream the port, b) after leaving the extruder, the material expands rapidly, the water contained in the material is evaporated, and the excess pressure in the extruder is rapidly equalized with the atmospheric pressure, c) the material thus obtained is dried to a moisture content of 10-14%.

8. The method according to claim 7, characterized in that the material obtained in steps b) and c) is mixed with starch and pressed to form disposable tableware and packaging.

9. The method according to claim 7, characterized in that the removal of excess water from the material in step a) is conducted in the extruder (6).

10. The method according to claim 7, characterized in that the removal of excess water from the material is conducted until the moisture of the material reaches 60% by weight.

11 . The method according to claim 7, characterized in that the length of the compression zone in step a) is 4D of the extruder cylinder diameter.

12. The method according to claim 7, characterized in that the temperature of the material extrusion process is 100-120°C (T1 ), and then the material is exposed to temperatures of 120-140°C (T2) and 110-200°C (T3).

13. The method according to claim 7, characterized in that the process temperature in step b) is from 110 to 140°C and the pressure in the expanding head of the extruder is 5-20 MPa.

14. The method according to claim 7, characterized in that, during the extrusion, the material is heated by friction and heating elements located on the extruder housing (6).

15. The method according to claim 7, characterized in that the extrusion of the material is carried out under an overpressure of 0.5-5 MPa upstream the venting ports.

16. The method according to claim 7, characterized in that the instantaneous, or maximum, or temporary pressure in the extruder cylinder does not exceed 25 MPa at any step of the extrusion process.

17. The method according to claim 7, characterized in that the pressure created is reduced and the water is evaporated as the material reaches the venting port (3, 4).

18. The method according to claim 7, characterized in that the resulting overpressure is reduced by using a vacuum fan (1 , 2).

19. The method according to claim 7, characterized in that the pomace and pulp are dried to a moisture content of 14%.

20. The method according to claim 7, characterized in that the material is dried on a belt dryer.