Tubex tree and vine shelter products have, since their earliest days, been made from polypropylene (or polyethylene); Although polypropylene is an appropriate raw material for our products we have, since 2004, been conducting research into and trials with alternative materials, with a key characteristic being biodegradability
The objective of this section of our website is to publish the progress with this project and to clarify some of the common misunderstandings that exist.
Objective of Project
There are various interrelated objectives of this project, of which the key ones are:
- to find a material that degrades more rapidly, but predictably, such that manual removal and disposal of the shelter is not required;
- to find an alternative material that will remain cost effective, in the light of predictable continuing increases in (oil and) PP price;
- to find an alternative material that comes from a sustainable source.
Various constraints have been placed upon this project, of which the key ones are:
- The resultant shelter must replicate the growth benefits provided by existing Tubex shelters;
- The product must deliver minimum performance (durability) requirements within a specified range of lifespan somewhere between 1 – 7 years;
- Production and delivery costs must be competitive;
- Environmental impact must be acceptable (comparable or better than polypropylene);
A range of options have been considered during research phases of this project including:
- Bio-composites or organic materials (e.g. paper, flax, hemp)
- Bio-polymers (polymers made from plant material)
- Hybrids – bio-polymers and PP
- Oxo-biodegradable PP
Note: there are many misunderstandings about the definition of “biodegradable” and other terms, some of which are now being standardised within European standards. See attached PDF document for key definitions (coming soon).
Our broad assessment of these options:
Various early trials were conducted upon these material options. As a result of assessments Tubex is currently focusing upon the Hybrid Bio PP option.
Trials have commenced in 2008 on a range of Hybrid Bio-PP options and the first full year assessments are being made at the end of 2009.
Monitoring of results thus far reveals a wide range of degradation options from the various material combinations that are being tested. See attached video (coming soon) for indication of how the shelters can degrade – this particular example shows a shelter that is “ripe” and ready to degrade speedily, having started life with a strength very similar to a new PP shelter.
Prospects for product release
At present Tubex is not prepared to release a product that has not received full field testing. Current field testing indicates that results do not always correlate with laboratory (accelerated) testing. It is important that a shelter lasts (or has a good chance of lasting) for a minimum period.
Therefore, we are currently focusing upon 1 – 2 year life products (primarily viticulture and landscaping environments) and will be extending this further during 2010/2011.
Other products on the market
Whilst we are taking a cautious approach in releasing biodegradable products, some producers are releasing or advertising biodegradable options. We are skeptical about these offerings for a number of reasons:
- definitions are wrong, unclear, inconsistent or incomplete;
- proper, whole life, testing of the degradation and the growth of plants has not been undertaken;
- understanding of the materials used is often poor;
- economics often do not add up – the prototype product will be too expensive;
- impacts upon the environment are not fully understood or published;
- companies producing the materials often hide with great care their compositions;
- reliance is often placed upon raw materials producers. We have found these to be unreliable;