The production of plastic worldwide has skyrocketed in recent decades: in the last 10 years alone, more plastic been manufactured than in the entire history of humanity. It is estimated that about 8 million tons of plastics end up in the oceans every year, and if these figures continue to rise, by 2050 there will be more plastic in the sea than fish.
We are increasingly accustomed to hearing this type of news and environmental concerns and new European guidelines are encouraging consumers look for alternatives to reduce the consumption of plastic on a daily basis, using more reusable products certified as recyclable or labelled as biodegradable or compostable.
TYPES OF PRODUCTS
Plastics is not limited to bags, bottles, containers, cutlery and other single-use products, but also a multitude of synthetic fibres used in textile products. Polyester, polyamide, polypropylene and acrylic fibres are used for the manufacture of clothing, upholstery, ropes, fishing nets, sanitary products including disposable surgical material, wet wipes, nappies and numerous other uses.
There are greener alternatives to single-use products, especially in packaging, and the range of alternatives are growing, such as 100% biodegradable nappies made entirely of cassava starch or “flushable” hygiene products, which are disposable down the toilet.
The vast range of sectors that consume textile products, and the contamination produced during manufacture, has driven the industry to research alternatives that reduce its environmental impact, such as the creation of new materials or processes to certify recycled fabrics.
The alternative to synthetic fibre are biopolymers. These materials are of natural origin, obtained from starch such as corn starch, soybeans, seaweed such as alginate, chitin from crustaceans or the shells and skin of different fruits: bananas, coconut and nuts. Polylactic acid or PLA is one of the best known and is used in biopolymers, since its properties are the most similar to those of polyester.
BIODEGRADABILITY VS COMPOSTABILITY
A material is biodegradable when it can be broken down chemically by the action of biological agents such as microorganisms, animals or plants. However, it is important to note that the decomposition process is always reliant on other physical agents such as prevailing environmental conditions: the sun, water, temperature and humidity favour these mechanisms.
Therefore, the biodegradation of a material will be different depending on where the material ends up: in the soil (burial), water (salt or fresh water), landfill (industrial or domestic compost) or treatment plants (active sludge).
A material is compostable when it can be degraded by the action of microorganisms turning it into carbon dioxide, water and biomass (fertiliser).
Therefore, a compostable material is biodegradable, but not all biodegradable materials are compostable, this will depend on the quality of the compost or the medium in which it is broken down.
Tests and acceptance criteria
There are as many test standards to assess whether a material is biodegradable, as there are biodegradation media and types of materials.
The most widely recognised standard and the one that establishes clear acceptance requirements is EN 13432: Standard on Packaging and Wrapping, which covers requirements for packaging that can be recovered through composting and biodegradation, a testing program and evaluation criteria for final acceptance of the package.
The standard establishes a series of tests in four phases to establish whether the material is finally compostable and biodegradable:
1. Characterisation: the type of material, its composition and the finishing chemicals are evaluated, according to raw materials, prohibited or restricted substances, for example heavy metals.
2. Biodegradability: The standard states that an aerobic biodegradation test or aerobic controlled composting test should be performed in compliance with ISO 14855-1. The criteria for the material to pass the test is that the percentage of biodegradation must be at least 90% of the total product in a maximum period of 6 months.
The biodegradation conditions are not only aerobic in all cases, so there are alternative methods if the above-mentioned aerobic biodegradation test cannot be performed because of the type of material, for example, in anaerobic media.
3. Disintegration: The product must be able to disintegrate in a biological compost over a maximum period of 12 months in a >2 mm sieve and should not retain more than 10% of the initial dry weight.
4. Compost quality: the resulting compost must be suitable for use without any environmental risk. Thus, the compost is evaluated physically and chemically and for toxins to plants.
The standard includes certain exemptions for some materials. In the case of materials of natural origin, for example, wood, wood fibre, paper pulp or jute are accepted as biodegradable without being tested, but they must be chemically characterised and meet the criteria of disintegration and compost quality.
In addition to this, there are other test standards for the evaluation of the behaviour of materials:
• ISO 846 and AATCC 30: Burial in an anaerobic (oxygen-free) environment. The test consists of bringing the material into contact with soil with a high content of microorganisms and determining if their action is capable of breaking the material down. The objective of the test is to demonstrate that the material is susceptible to degradation under the conditions in which the test has been performed.
• UNE 149002: Biodegradation in active sludge: evaluation of aerobic and anaerobic biodegradation and requirements for disposable products down the toilet.
• EN ISO 19679: Plastics. Determination of aerobic biodegradability of non-floating plastic materials in a seawater interface.
• ISO 14852: Determination of the final aerobic biodegradability of plastic materials in aqueous media. Method according to the generated carbon dioxide analysis
Solutions provided by AITEX
AITEX can perform different types of tests for the evaluation of the suitability of a product to be labelled as biodegradable and / or compostable. We have experience in advising companies on labelling compliance and for the search for new materials and alternatives in the design and composition of products. In addition, regarding the certification of textile recycling processes, AITEX is a recognised body to issue the GRS (Global Recycled Standard) and the RCS (Recycled Claim Standard) certificates.