STANDARDS OF BIOPLASTICS
Corn starch is currently the main raw material being used in the manufacture of bioplastic resins. BIOPLAST (main component corn-starch), and PolyActide (PLA) (made from corn-starch as well) are currently the 2 main resins (raw materials), being used today in the production of compostable & biodegradable plastics and are certified for compostability under standards set by international organizations. However, other resins are coming into the market made from potato starch, soybean protein, cellulose etc. Most of these are currently not certified for compostability, though some are for biodegradability. The field of bioplastics is constantly evolving with new materials and technologies being worked on and being brought to market.
Today, the terms biodegradation, biodegradable materials and compostability are very common but frequently mis-used. Consequently, this is a source of misunderstanding. The European Standard EN13432 "Requirements for packaging recoverable through composting and biodegradation - Testing scheme and evaluation criteria for the final acceptance of packaging" resolves this problem by defining the characteristics that a material must have, in order to be defined as "compostable". This norm is a reference point for material manufacturers, public authorities, composters and consumers.
According to the European Standard EN13432, a compostable material must have the following characteristics: Biodegradability - this is determined by measuring the actual metabolic conversion of the compostable material into carbon dioxide. This property is quantitatively measured using the standard test method, EN14046 (which is also published as ISO 14855: biodegradability under controlled composting conditions). The acceptance level is 90%, which must be reached in less than 6 months.
Disintegrability - that is, the fragmentation and loss of visibility in the final compost (absence of visual contamination). This is measured with a composting test (EN14045). The test material is degraded, together with organic waste, for 3 months. After this time, the compost is sieved with a 2 mm sieve. The residues of test material with dimensions higher than 2 mm are considered as not having disintegrated. This fraction must be less than 10% of the initial mass. Absence of negative effects on the composting process - this is checked by a composting test.
Low levels of heavy metals (below the predefined maximum values), and absence of negative effects on the quality of the compost (e.g. reduction of the agronomic value and presence of eco-toxicological effects on the growth of plants) - a plant growth test (OECD test 208, modified) is carried out on compost samples where the degradation of the test material has taken place. There must be no difference from control compost. Other chemical-physical parameters that must not be different from those of the control compost after the degradation are level and concentration of pH value, salinity, volatile solids, Nitrogen, Phosphor, Magnesium and Potassium.
However; Compostable Plastic is plastic which is "capable of undergoing biological decomposition in a compost site as part of an available program, such that the plastic is not visually distinguishable and breaks down to carbon dioxide, water, inorganic compounds, and biomass, at a rate consistent with known compostable materials (e.g. cellulose). and leaves no toxic residue." American Society for Testing & Materials (ASTM). In order for a plastic to be called compostable, three criteria need to be met:
Biodegrade - break down into carbon dioxide, water, biomass at the same rate as cellulose (paper).
Disintegrate - the material is indistinguishable in the compost, that it is not visible and needs to be screened out
Eco-toxicity - the biodegradation does not produce any toxic material and the compost can support plant growth.
bioplast Environmental uses many testing laboratories to test the biodegradable plastics for their 3rd party test results. These tests are not our own design, but are created by an organization known as the American Society of Testing and Materials (ASTM), European test (EN), ISO, OK-BIOBASED and are the most recognized type of commercial and industrial tests and standards available. These tests show that under anaerobic and aerobic conditions, bioplast biodegradable additive works in most major polymers.
ASTM D 6400
VIÇOTTE / OK-COMPOST, OK-BIOBASED