RU2822572C1 - Biodegradable starch-based film for production of goods such as shoe covers, covers, caps, bags and packaging material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to organic high-molecular weight articles, particularly to a biodegradable film, and can be used as a production and/or packaging material. Biodegradable film contains potato starch, polyvinyl alcohol PVA 26-99, calcium carbonate with the following content of components, wt.%: potato starch 55–59.1, polyvinyl alcohol PVA 26-99 40–44, calcium carbonate 0.85–0.9. Invention also relates to shoe covers made from a biodegradable film, containing a mounted textile gum.

EFFECT: reduced noise when using the film, shorter time for decomposition of the film, high strength of the film, high shock-absorbing properties for protecting the packed object and almost complete reduction of moisture permeability.

4 cl, 1 tbl, 3 ex

Description

The invention relates to the field of organic high-molecular products, in particular to film, and can be used as a production and/or packaging material [C08J 5/18, C08K 3/26, C08L 29/04, C08K 5/053].

BIODEGRADABLE PACKAGING MATERIAL FOR FOOD PRODUCTS AND THE METHOD OF ITS PREPARATION are known from the prior art [CN 112011139 A, publ. 12/01/2020]. Biodegradable food packaging material consists of the following components: polyvinyl alcohol (73-76 parts by weight), modified wood powder (15-20 parts by weight), vegetable starch (35-42 parts by weight), dioctyl maleate (3-5 parts by weight) , modified castor oil (1-3 parts by weight), nanocalcium carbonate (8-12 parts by weight), nanodiatomaceous earth (6-10 parts by weight), plasticizer (5-8 parts by weight) and basalt fiber (0.3-0.8 weight part).

The disadvantage of the analogue is the long decomposition time of the packaging material, low strength of the packaging material, low shock-absorbing properties of the packaging material, lack of moisture resistance, as well as a large amount of noise when using this packaging material.

Known from the prior art is a DOUBLE-DECOMPOSIBLE PLASTIC FILM OF STARCH AND POLYVINYL ALCOHOL [CN 104109263 A, publ. 10/22/2014]. Starch-polyvinyl alcohol polyethylene film of double destruction, characterized in that it is made from the following raw materials: starch 50-65 parts, polyvinyl alcohol 15-30 parts, wormwood glue 5-10 parts, hydroxypropyl cellulose. 2-8 part, pullullan polysaccharide 5-10 part, nanosilicon 3-6 part, zinc stearate 5-10 part, oxidized polyethylene wax 4-8 part, ethyl silicone oil 2-7 part, calcium carbonate 3-5 part, glutaraldehyde 4 -10 part, stearyl alcohol 3-5 part.

The disadvantage of the analogue is the long decomposition time of the film, low strength of the film, low shock-absorbing properties of the film, lack of moisture resistance, as well as a large amount of noise when using this film.

The closest in technical essence is BIODEGRADABLE AGRICULTURAL MULCHING FILM BASED ON POLYVINYL ALCOHOL, HARMFUL TO THE ENVIRONMENT [CN 111303572 A, publ. 06/19/2020]. Biodegradable environmentally friendly agricultural mulch film based on polyvinyl alcohol is characterized by the content of the following components in parts by weight: 65-68 parts of modified polyvinyl alcohol, 14-16 parts of gelatinized starch, 7-8 parts of plasticizer, 1-2 parts of cross-linking agent, 6-10 parts microcrystalline wax, 3-5 parts glycerin, 5-7 parts aluminum sulfate whiskers, 6-9 parts nanofiller, 13-15 parts calcium carbonate and 45-50 parts deionized water;

The main technical problem of the prototype is the long decomposition time of the film due to the large number of components included in the film, low strength of the film, low shock-absorbing properties of the film, lack of moisture resistance, as well as a large amount of noise when using this film.

The objective of the invention is to eliminate the disadvantages of the prototype for the production of wear-resistant products.

The technical results of the invention consist in reducing noise when using the film. In addition, the technical result of the invention is to reduce the decomposition time of the film. In addition, the technical result of the invention is to increase the strength properties of the film. In addition, the technical result of the invention is to increase shock-absorbing properties to protect the packaged object. In addition, the technical result of the invention is an almost complete reduction in moisture permeability.

The technical result of the invention is achieved due to the fact that the biodegradable production film includes starch, polyvinyl alcohol, calcium carbonate, characterized in that the component content is, wt. %:

Starch 55-59.1 Polyvinyl alcohol 40-44 Calcium carbonate 0.85-0.9

In particular, the film contains a natural dye or a mixture of natural dyes; algae powder or spirulina powder, or spinach powder, or Japanese matcha tea, or barley leaf juice are used as a natural dye.

In particular, the film thickness is from 18 microns to 20 microns, the film elasticity coefficient is at least 100 MPa, and the film elongation at break is at least 400%.

In addition, the technical result is achieved due to the fact that shoe covers made of film contain mounted textile elastic

The present invention is implemented through the following technical means.

Biodegradable and compostable starch-based film for the production of goods (such as shoe covers, covers, hats, bags, packaging material, etc.) is made from granules having the following composition:

Unmodified starch used as a biodegradation agent. The source of starch is plants such as potatoes, corn, wheat, rice, etc.

Polyvinyl alcohol (hereinafter referred to as PVA), which is a water-soluble white powder used as a thermoplastic matrix. The advantage of PVA is the lack of toxic effects on the environment. When mixed in an aqueous environment with starch, it forms a transparent, biodegradable film that is chemically and mechanically resistant.

Calcium carbonate is used as a plasticizer. Calcium carbonate also reduces the glass transition temperature of the film and increases the flexibility of the film.

The percentage of components is as follows:

Unmodified starch (56% to 59.1%), PVA (40% to 44%), calcium carbonate (0.85% to 0.9%). If necessary, the film is tinted with a natural dye, such as algae powder or spirulina powder, or spinach powder, or Japanese matcha tea, or barley leaf juice.

To obtain film:

PVA powder is added to distilled water and the PVA powder is completely dissolved at a temperature of 70 to 75 °C, constantly stirring until the PVA solution with distilled water becomes clear.

Then starch powder is added to the solution of PVA and distilled water.

The mixture of PVA solution and starch is stirred at a speed of at least 200 rpm.

After the mixture of PVA and starch solution is completely mixed, calcium carbonate is added to the mixture, and if necessary, a natural dye is added.

From the mixture, granules are obtained that are used in an extruder to produce a film with a thickness of 18 to 20 microns, an elasticity coefficient (in dry condition) of at least 100 MPa, and an elongation of the film at break of at least 400%.

This film can be used as a raw material for the production of clothing items, for example, by soldering textile elastic to the edge of the film, disposable caps or shoe covers can be obtained, including disposable caps and shoe covers for medical use.

An example of the invention.

The present invention has been implemented by the following steps:

The following components were used as the basis for the granules required for film production:

1. Polyvinyl alcohol, in particular PVA 26-99, having the following characteristics: hydrolysis 98.85 mol%, viscosity 75.9 mPas, volatile substances 3.825%, purity 94.85%, pH level 7. The proportion of polyvinyl alcohol in the total mass film was 40.0;

2. Potato starch, in particular unmodified potato starch, which is a white, odorless, fine powder. The proportion of starch in the total mass of the film was 59.1%;

3. Calcium carbonate, which is a white powder. The proportion of calcium carbonate in the total mass of the film was 0.85%;

4. Natural dye, in particular, barley leaf juice, when using barley leaf juice, the mixture turns greenish-yellow. The proportion of barley leaf juice in the total mass of the film was 0.05%.

Polyvinyl alcohol PVA 26-99, in an amount of 4,000 kg, is poured into a mixer-granulator, which has previously been filled with distilled water heated to a temperature of 72°C. The mixer is activated and the speed is gradually increased to 200 rpm, stirring of the solution continues until the polyvinyl alcohol is completely dissolved, and the solution of polyvinyl alcohol and distilled water should become transparent.

Then unmodified potato starch in an amount of 5,900 kg is added to a solution of polyvinyl alcohol PVA 26-99 and distilled water, after which the mixture is stirred until smooth.

After complete mixing, calcium carbonate is added to the mixture in an amount of 0.089 kg, as well as a dye - barley leaf juice, in an amount of 0.011 kg. After adding calcium carbonate and barley leaf juice, the mixture is stirred until the mixture is smooth and the natural coloring evenly colors the mixture.

After bringing the mixture to a homogeneous state, the number of revolutions per minute is changed on the mixer-granulator, gradually increasing to 1000 revolutions per minute. Under the action of centrifugal force and the binder, granules begin to form inside the mixer-granulator, gradually increasing in size and taking on a compact structure.

To produce film, granules are poured into an extruder. Inside the extruder, the granules are heated, and then a film is formed from the heated granules by blowing. The film is subsequently formed into rolls.

To carry out the experiments, 9 pieces of biodegradable film with a thickness of 20 microns, a width of 50 cm, and a length of 50 cm were taken.

As a first experiment, 2 pieces of film were used.

Each of the segments was cut to dimensions of 40 cm in length and 14 cm in width. A textile elastic band was soldered to each of the segments along the perimeter, resulting in an imitation of shoe covers.

To compare the noise level from shoe covers from the proposed solution, the following was used:

As a prototype: shoe covers made from prototype film.

Additionally, disposable medical shoe covers were also taken for comparison.

A general comparison of characteristics is shown in Table 1.

Table 1 - Comparison of characteristics of shoe covers made from different films

Shoe covers made of polypropylene Shoe covers made from prototype film Shoe covers made from biodegradable film Shoe covers sizes 400 mm by 140 mm 400 mm by 140 mm 400 mm by 140 mm Material of manufacture Polypropylene Modified polyvinyl alcohol, gelatinized starch, plasticizer, crosslinking agent, microcrystalline wax, glycerin, aluminum sulfate whiskers, nanofiller, calcium carbonate deionized water Starch, polyvinyl alcohol, calcium carbonate, color (barley leaf juice) Thickness 20 µm 20 µm 20 µm Amount of noise 57 dB 43 dB 35 dB

The device used to measure noise was 2250.

The measurements were taken in a room, the walls of the room were covered with acoustic foam. The distance from the shoe covers to the noise measuring device is 1 meter.

The noise level from shoe covers made of polypropylene was 57 dB, the noise level from shoe covers made from the prototype film was 43 dB, and the noise level from shoe covers made from biodegradable film was 35 dB.

Accordingly, the noise, compared with shoe covers made of polypropylene, decreased by 39.6%, and the noise, compared with shoe covers made of the prototype film, decreased by 18.7%.

For the second experiment, 1 piece of biodegradable film was used. To compare the decomposition time, an experiment was carried out to measure the decomposition time of a 50 cm by 50 cm piece of film in soil, at constant temperature and humidity.

To simulate the conditions of placing the film in natural conditions for further decomposition, the following was used:

A container 70 cm by 70 cm at the base and 60 cm in height, at the bottom of which soil 20 cm thick was evenly distributed, containing high-moor peat (40% of the total mass of the soil), lowland peat (20% of the total mass of the soil), perlite ( 20% of the total soil mass), sphagnum moss (10% of the total soil mass), mullein (5% of the total soil mass), charcoal (5% of the total soil mass).

Then a film was placed on the soil layer. The film was covered on top with a layer of soil of similar thickness.

Similar actions were carried out with the prototype film.

The experiment was carried out at a constant temperature of 22.7°C, 90% humidity and UV light running for 6 hours per day.

After 4 months, the layer of soil was removed from the proposed film and the prototype film. The proposed film completely dissolved in the soil under the influence of bacteria and fungi contained in the soil, and the prototype film dissolved by 78 percent. Accordingly, the dissolution rate of the proposed film is 27.5% greater than the dissolution rate of the prototype film.

For the third experiment, 3 pieces of biodegradable film were used.

Shoe covers were produced from two segments by analogy with the first experiment.

And the characteristics of shoe covers made from biodegradable film and the prototype film, as well as shoe covers made from polypropylene, were compared. The comparison consisted of the number of steps that can be taken with shoe covers on the shoes until a hole is formed in the shoe covers at the point of contact with the sole.

The floor covering on which the comparisons took place was made of ceramic tiles. The room itself has the shape of a circle, the circumference of which is 50 meters and the width is 2.5 meters.

Using shoe covers made of polypropylene, 20 microns thick, 40 cm long and 14 cm wide, 288 steps were taken to the first holes.

Using shoe covers made from a prototype film, 20 microns thick, 40 cm long and 14 cm wide, 326 steps were taken to the first holes.

Using shoe covers made from biodegradable film, the number of steps increased by 29.1% in relation to shoe covers made of polypropylene, and by 14.1% in relation to shoe covers made from the prototype film, and amounted to 372 steps.

A tensile experiment was carried out with the third piece of biodegradable film, in which:

The device used was an Instron 5900 extensometer.

As a comparative sample, a prototype film with a thickness of 20 microns, a length of 50 cm and a width of 50 cm, made of biodegradable material, was used.

When stretching the prototype film, the following was revealed: the tensile strength of the prototype film was 316%, and the load at which the rupture occurred was 3.38 kg.

When stretching the proposed biodegradable film, the following was revealed: the tensile strength of the prototype film was 422%, and the load at which the rupture occurred was 4.21 kg.

To conduct the fourth experiment, two pieces of biodegradable film were taken, welded together in such a way that the internal cavities were bubble packaging material.

The essence of the experiment was to evaluate the properties of film protection of an object on which physical impact was directed.

For the experiment we used:

Shock sensor, namely piezoelectric accelerometer ADXL375

As the first packaging material for the shock sensor, a prototype film made in the form of bubble packaging material was used.

The second packaging material for the shock sensor was a biodegradable film made in the form of bubble packaging material.

A metal ball weighing 100 grams was used as an element of physical impact.

The shock sensor was mounted on a stand; a ball guide, 1 meter long, was mounted at an angle of 30 degrees to the stand. The ball guide directs the ball to the center of the sensor, hitting which produces a physical impact on the sensor and measures the force of the impact.

The ball was fixed at a distance of 30 cm from the sensor and released, while the initial speed of the ball was zero.

A sensor placed in the first packaging material, made of high-density polyethylene, recorded an impact force of 384 N. At the same time, the bubbles that received the impact partially burst.

A sensor placed in a second packaging material made of biodegradable film recorded an impact force of 216 N. In this case, not a single bubble burst. Accordingly, the packaging material, which is a bubble material, absorbed the impact 43.75% better than a similar solution.

To conduct the fifth experiment, one piece of biodegradable film was taken and soldered together to form a container for liquid.

The essence of the experiment was to compare the moisture permeability of the films.

The prototype film, soldered in a similar way, was glued to the wall at a distance of 1 meter from the floor. Distilled water in an amount of 100 ml was poured inside the prototype film.

The biodegradable film was glued to the wall at a distance of 1 meter from the floor. Distilled water in an amount of 100 ml was poured inside the prototype film.

Also glued to the wall was a disposable glass made of plastic, inside of which 100 ml of water was also poured. This glass is necessary because, based on the remaining water, the amount of water that has evaporated as a result of the experiment is measured.

The indoor temperature was 22.7°C and the humidity was 90%. Under these conditions, the samples were left for 24 hours.

During the experiment, an accumulation of liquid formed under the prototype film, periodically dripping from an imitation glass made from the prototype film. In the final calculation, 57.6 ml of distilled water remained inside the prototype film.

In an imitation glass made of biodegradable film, 86.2 ml of distilled water remained.

There are 86.4 ml of distilled water left in the plastic glass.

As a result of the experiment, waterproof properties were proven when compared, since when compared with a plastic cup, the film let through 0.2 ml of water, which can be attributed to measurement error and water remaining on the walls of the glass.

Experiments with prototypes have shown that when using biodegradable film for the production of goods, the following is observed:

1. Noise reduction compared to shoe covers made of polypropylene decreased by 39.6%, and noise, compared to shoe covers made of the prototype film, decreased by 18.7%.

2. Reducing the decomposition time of biodegradable and compostable film by 27.5% compared to a similar solution.

3. Increasing the strength properties of the film, namely, increasing the number of steps taken in shoe covers made of biodegradable film until a hole is formed at the point of contact of the shoe covers with the sole, by 29.1% compared to shoe covers made of polypropylene and by 19.1% compared to shoe covers made from the prototype film, as well as to achieve 422% tensile strength, which is 106% more than a similar solution when compared with a similar film, and also by 24.5% increasing the maximum mass that the film can withstand when breaking.

4. Increasing shock-absorbing properties to protect the packaged object, namely packaging material made from biodegradable and compostable film, which is bubble wrap, absorbed impact 43.75% better than similar bubble wrap.

5. Almost complete reduction in moisture permeability in comparison with a similar prototype film.

Thus, due to the fact that the biodegradable production film includes starch, polyvinyl alcohol, calcium carbonate, characterized in that the component content is, wt. %:

Starch 55-59.1 Polyvinyl alcohol 40-44 Calcium carbonate 0.85-0.9

A technical result is provided such as reducing noise when using the film; in addition, a technical result is provided such as reducing the decomposition time of the film; in addition, a technical result is provided such as an increase in the strength properties of the film; in addition, a technical result is provided such as an increase in shock-absorbing properties for protection of the packaged object, in addition, such a technical result as an almost complete reduction in moisture permeability is ensured.

Claims (5)

1. Biodegradable film, including potato starch, polyvinyl alcohol PVA 26-99, calcium carbonate, characterized in that the component content is, wt. %: Potato starch 55-59.1 Polyvinyl alcohol PVA 26-99 40-44 Calcium carbonate 0.85-0.9 2. The film according to claim 1, characterized in that it contains a natural dye or a mixture of natural dyes; spirulina powder or spinach powder, or Japanese matcha tea, or barley leaf juice are used as a natural dye. 3. Film according to claim 1, characterized in that the film thickness is from 18 microns to 20 microns, the film elasticity coefficient is at least 100 MPa, and the film elongation at break is at least 400%. 4. Shoe covers made of film according to claim 1, containing mounted textile elastic.