Technical area

The invention concerns bio-containers for the collection of bio-waste and municipal waste, especially a bio-container modified into a shopping bag which after serving its primary function fulfils a secondary function as a bio-container.

State of the art

For the collection of bio-waste designated for composting there are designated bio- containers found mainly in households. These are in the form of bags, usually of a size suitable for insertion into rubbish bins. Once full, such a bag is sealed either by tying a knot at the top or if so equipped, with a drawstring that runs in a tunnel around the open end of the bag. Existing containers are supplied either as loose bags, or blocked or as a perforated tube with welded bottom wound into a roll. Mainly bag containers with a free end that is sealed by tying a knot are produced in this way. Mainly bags with a drawstring are produced as loose pieces.

Considering their further use (composting in industrial composters), these products must be produced from material that has the same characteristics as bio-waste during composting, which means that it will also break down into water, carbon dioxide and organic remains. Such materials are biodegradable polymers from the group including polylactides, for example, modified polylactic acid (PLA), modified starch and co-polyesters.

In this regard, well-known are shopping bags with a secondary application as a container for the collection of waste, especially bio-waste and municipal waste, which are composed of a film bag made of biodegradable or oxodegradable polymer material, whereby this bag, apart from featuring handles to facilitate carrying in the upper part, also have a sealing element or elements.

The drawback of all so far known bio-container designs is the differing decomposition time of the bio- waste and the material of the bag (bio-container). Once placed in the composter, the temperature of the deposited material climbs to 60 to 70°C within a few minutes. At this temperature and due to the action of moisture, oxygen and micro-organisms, decomposition takes place in the presence of oxygen - aerobic, and compost is created. However, if bio-material (bio-waste) is sealed within the bag, which decomposes slowly (according to ISO 13432, 80% of material turns into compost after 180 days in the conditions of industrial composting), decomposition occurs at higher temperatures without the presence of oxygen - anaerobic (rotting). This process is undesirable and substantially reduces the value of the produced compost.

For the collection of other municipal waste, which at present is further processed by depositing on rubbish dumps, households use bag containers of the same shape as bags for bio-waste, delivered in the same form (loose, tear-off, with drawstring). These are manufactured from common polymers - especially from polyethylene in all its variants - LDPE, HDPE, LLDPE, mLLDPE and mixtures of these, sometimes including oxodegradable additives to speed up decomposition on the rubbish dump. The drawback in using such bags is that municipal waste comes in all shapes and forms (e.g. formed plastic packaging, tins) and after sealing the bag, be it loose or with a drawstring, its shape and volume do not adapt to the items it contains. The bag is "inflated" with considerable unutilised volume. Once the bag is disrupted on the rubbish dump or during composting, mixing together of the contents occurs, which mainly on rubbish dumps may take several years and makes effective utilisation of the rubbish dump much more difficult.

Another drawback of both types of bag (for bio-waste and municipal waste) is that in terms of safety, these products are dangerous (danger of suffocation when placed over the head and when used in children's games). Thus, they must be kept out of reach of children and must also be marked as possibly dangerous. As these bags are produced for more countries, they should be marked with safety information in the languages of the countries where they will be used, which is not always easy to ensure.

The drawback of current designs is also the one-off use of containers just for the collection and disposal of waste. Current materials used for containers, mainly for the collection of bio-waste, are special polymers that cost up to 5 times more than standard polymers. The commonly utilised economic advantage of multi-usability, which is often touted, for example, for carrier bags, is not possible in the case of collecting waste using common bio-containers.

Principle of the invention

A bio-container for the collection of bio-waste and municipal waste according to the invention helps to eliminate the above-mentioned shortcomings, especially when designed as a shopping bag with a secondary function as a bio-container (made as a bag made of polymer film material, which apart from featuring handles to facilitate carrying in the upper part, also has a sealing element or elements). The principle of the invention lies in the fact that the bio- container bag is made of polymer film material that features a set of through holes, cut-outs and/or cuts.

The set of through holes will preferably be a set of round holes with a diameter of 0.5 to 2 mm, whereby the density of such holes is 1 to 2 per cm ² . Individual round holes can have a reinforcement formed around their perimeter.

In another variant, the polymer film bag of the bio-container is provided with a set of round holes with a diameter of 2 to 20 mm, 5 to 10 mm being the best size, whereby these holes are arranged in a diamond or rectangular shape with centre spacing equal to 4 to 6 times their diameter.

Another option is a set of cuts running horizontally across the bag or diagonally across it, whereby individual cuts are 5 to 20 mm long and are arranged in rows with horizontal spacing of 5 to 20 mm and vertical spacing of 20 to 50 mm.

The polymer film material can also be provided with a set of cut-outs in the shape of a cross or letter Y, with individual branches of the cut-outs 5 to 10 mm long.

The set of holes, cut-outs and/or cuts in the polymer film material can preferably be created only in the upper part of the bag, with a minimum distance from the bottom edge of the bag of 0.1 to 0.2 the height of the bag.

The polymer material of the bio-container bag can preferably be made of biodegradable or oxodegradable polymer material. The biodegradable polymer film material of the bio-container bag is material that comes from the group including polylactic acid, modified starch and co-polyester. The oxodegradable polymer film material of the bio- container bag is material that is based on certain types of polyethylene - LDPE, LLDPE, mLLDPE or mixtures of them, featuring an oxodegradable additive or where suitable, an inorganic filler.

Disruption of the integrity of the film of the bio-container bag according to the invention by holes, cut-outs or cuts, apart from improving the utility properties of the bio-container on rubbish dumps, also removes the shortcomings resulting from the unsafe use of bag containers. The given modification can also be carried out on the whole area of the bag or just in its upper part, away from the bag's bottom. This design is advantageous in that when dumping bio-waste, a low-viscosity proportion of it is sometimes created - liquid that can escape through the holes and cuts and pollute the surroundings.

Improvement of ecological and financial impacts through the application of these products is given by the fact that the upper part of the bag with drawstring is provided with soft loops. The primary use of such a product is then as a shopping bag (for multiple use also) and the subsequent secondary function is use as a bio-container for bio-waste or municipal waste. Examples of practical designs of the invention

Example 1

In this example, the bio-container is in the form of a plastic carrier bag, produced as a welded plastic film bag, with dimensions of 350 mm (width) by 460 mm (height), with a bottom turnup of 50 mm. The circumference of the upper part of the bag features a welded tunnel 40 mm wide, in which is placed tape made of plastic or textile material and 1 mm wide. The bag is further provided with welded plastic handles 0.110 mm thick to facilitate carrying. The container's material is film of thickness 0.080 mm made from biodegradable polymer based on a derivative of polylactic acid (PLA). This film features a set of round holes 1 mm in diameter, arranged 1 cm apart from each other both horizontally and vertically.

Example 2

The bio-container is again in the form of a plastic carrier bag, produced as a welded plastic film bag with dimensions of 350 mm (width) by 460 mm (length) with a bottom fold-up of 50 mm. The circumference of the upper part of this bag features a welded tunnel 40 mm wide, in which is placed tape made of plastic or textile material and 15 mm wide. The bag is further provided with welded plastic handles 0.110 mm thick to facilitate carrying. The container's material is oxodegradable polymer film that contains 85 % by weight of LDPE of weight 918 kg/m ³ , 5 % by weight of the oxodegradable concentrate ADD-X from the company BIOTECH, and 10 % by weight of micronised limestone.

This film features a set of cut-outs in the shape of crosses with a shoulder length of 5 mm. The lower part of the container (the bottom) does not feature any cut-outs for a distance of 0.2 times the overall length (i.e. 92 mm).

Example 3

A bio-container in the form of a plastic carrier bag is produced in the same dimensions, from the same material and in the same basic construction design featuring a tunnel and plastic handles, as examples 1 and 2.

The film of the bio-container bag features a set of round holes 1 mm in diameter, arranged 1 cm apart from each other both horizontally and vertically. The edges of these holes are reinforced (note: these holes are created using technology that pierces the material with hot needles)

Example 4

A bio-container in the form of a plastic carrier bag is produced in the same dimensions, from the same material and in the same basic construction design featuring a tunnel and plastic handles, as examples 1 and 2.

The film of the bio-container bag features a set of cuts 10 mm long that run horizontally across the bag. These cuts are arranged in rows with horizontal spacing of 20 mm and vertical spacing of 25 mm.

Example 5

A bio-container in the form of a plastic carrier bag is produced in the same dimensions, from the same material and in the same basic construction design featuring a tunnel and plastic handles, as examples 1 and 2.

The film of the bio-container bag features a set of round holes 5 mm in diameter that are arranged in a diamond shape with a centre spacing of 25 mm.