WO2008037985A1

WO2008037985A1 - Biodegradable tree shelter with prolonged durability

Info

Publication number: WO2008037985A1
Application number: PCT/GB2007/003652
Authority: WO
Inventors: André GREEN; Bhukandas Parbhoo
Original assignee: Tubex Limited
Priority date: 2006-09-26
Filing date: 2007-09-25
Publication date: 2008-04-03
Also published as: GB0718746D0; GB0618988D0; GB2442333A

Abstract

An apparatus for protecting a young plant, the apparatus comprising a longitudinal sleeve member with a first end for insertion into the ground and a second end located at the opposing end of the longitudinal sleeve member to the first end, and a protector located at the first end and extending at least partially along the sleeve member, the protector comprising a coating of degradation-resistant material. Also provided is an apparatus for protecting a young plant, the apparatus having a substantially sleeve-like form comprising a support structure covered in a translucent film, the support structure allowing the passage of light therethrough. Also provided is a method for the production of such apparatuses.

Description

BIODEGRADABLE TREE SHELTER WITH PROLONGED DURABILITY

Background to the invention

The present invention relates to apparatus for protecting and promoting the growth of botanical plants such as trees, shrubs, fruit trees, vines, etc. In particular, the present invention relates to a biodegradable apparatus for protecting a young plant.

Tree shelters are well known in the prior art and typically comprise a plastic structure curved around a growing young plant. Often the plastic used is translucent to allow some light to reach the growing young plant through the walls of the structure. If light is only provided from above at the upper opening of the structure, the protected young plant is likely to grow in a weak and rangy manner and become tall, but spindly, with little side-branch growth and small root structure. Therefore, it is important to allow light to reach the young plant through the walls of the structure. Often the opaque nature of the structure walls of tree shelters made of biodegradable composites does not allow light through. Therefore, in some instances, apertures are provided in the walls of the structure through which light can reach the young plant. However, often such structures do not provide sufficient protection to the young plant from the wind which may blow through the apertures and access the young plant and its environment Moreover, the apertures weaken the whole structure and become crack initiation points available to water and fauna alike.

There is therefore a need for a robust biodegradable tree shelter which protects the young plant from the elements of nature whilst still allowing sufficient light to reach the growing young plant.

A further disadvantage of many existing tree shelters, particularly when composed of fossil based materials like polypropylene and polyethylene, is that they typically have to be removed from around the growing young plant after an amount of time has passed and the young plant has become larger. Even where weakened portions are provided within the structure of the tree shelter so as to release the tree shelter from around the young plant as it expands and exerts pressure on the tree shelter, the tree shelter still needs to be retrieved to avoid littering the landscape and posing a potential danger to local wildlife.

One solution to such a problem is to make the structure of the tree shelter from a biodegradable material such that the shelter degrades over time before becoming a problem to the expansion of the growing young plant. However, such biodegradable materials are often opaque and do not provide sufficient translucence and therefore do not allow enough light to reach the young plant. Although one or more apertures may be provided in the structure of the tree shelter to allow more light to access the young plant, this may weaken the structure, allow wind to access the shelter and thus the young plant, and provides initiating loci for attacks from the elements of nature.

An important disadvantage of the biodegradable material used in existing tree shelter applications is its premature degradation due to its very nature and composition. Although additives can be incorporated in the materials, the biomaterial itself is likely to be susceptible to attacks from the physical, chemical and biological elements of nature. Furthermore, the longevity of the product in an outdoor environment becomes less controllable.

There is therefore a need for a robust and resilient tree shelter structure of a biodegradable material without the need for apertures in the walls of the tree shelter structure.

A further major potential problem experienced with many tree shelters, particularly tree shelters composed of biodegradable materials, is that because they are often pushed into the ground in use, a portion of the tree shelter remains anchored in the ground throughout use and will thus biodegrade at a faster rate than the remainder of the tree shelter. This results in a reduced life of use of the tree shelter where the anchored portion may degrade in an accelerated manner whilst the remainder of the tree shelter remains in good condition around the young plant.

When the anchored portion degrades, the remainder of the tree shelter is no longer anchored in the ground (as the portion beneath the ground rots and breaks away, either wholly or partially, from the remainder of the tree shelter). As a consequence the tree shelter is then free to move around the young plant, for example, as a result of wind forces and the like, and allows access from below to animals that may attack the young plant. Subsequent damage to the young plant is often an undesirable consequence of this.

There is therefore a need for a tree shelter which avoids premature degradation of a ground-anchored portion of the tree shelter structure during use.

Summary of the Invention

The present invention seeks to address the problems of the prior art.

Accordingly, a first aspect of the present invention provides an apparatus for protecting a young plant, the apparatus comprising a longitudinal sleeve member with a first end for insertion into the ground and a second end located at the opposing end of the longitudinal sleeve member to the first end, and a protective member located at the first end and extending at least partially along the sleeve member, the protective member comprising a coating of degradation-resistant material.

Preferably, the first end of the longitudinal sleeve that is inserted into the ground also extends about the ground. This assists in protection of the portion of the sleeve member extending just above ground level from degradation. This is important as bio degradation is more pronounced in the ground and in the surface region just above ground level.

In one embodiment, the degradation-resistant material is a polypropylene film. However, it will be appreciated that any other suitable degradation-resistant material may be used as an alternative to polypropylene (PP), high density and low density polyethylene (PE), polyvinyl chloride (PVC), polyester (PET).

The whole of the apparatus may be formed from a sustainable biodegradable material or biodegradable biopolymeric material with bioresistant properties.

Alternatively, an end portion, for example, a petrol-based end portion may be added to the sleeve-like structure after manufacture of the sleeve-like structure.

Alternatively, the sleeve-like structure may be dipped or coated in a protective coating at that portion of the sleeve-like structure that is desired to have increased bioresistance. However, it will be appreciated that these methods of manufacture are presented as non-limiting examples only and any other suitable method of manufacture known to the skilled person may be used.

A further aspect of the present invention provides an apparatus for protecting a botanical plant, the apparatus having a substantially sleeve-like form comprising a support structure composed at least in part of a biodegradable material, and covered, at least in part, in a translucent film, the support structure allowing the passage of light there through.

It is preferred that where only a region of the support structure is composed of a biodegradable material that it is the portion of the support structure that extends below the ground and preferably also the portion that extends just above ground level that is composed of biodegradable material. As mentioned above, this is important as biodegradation is more pronounced in the ground and in the surface region just above ground level. Preferably, the film covering the support is composed at least in part of a biodegradable material.

Alternatively, the film covering the support structure may be transparent.

In one embodiment, the support structure is in the form of a mesh. The mesh may contribute a degree of strength to the support structure of the apparatus, thereby assisting the support structure in assuming a semi-rigid form in use. The support structure may be further strengthened by taking the form of a twin-walled structure, such that the apparatus is double-walled and therefore stronger and lighter in weight than a single-walled structure.

As an alternative to the support structure taking the form of a mesh, the support structure may take the form of a plurality of spaced apart elongate supports. The supports may be hollow or may be solid, but where the elongate supports are hollow, the resultant support structure is light-weight without compromising on strength. This may be particularly advantageous, for example, for the purposes of transportation of the apparatus to the location at which it is to be used.

In one embodiment, the plurality of spaced apart elongate supports are substantially parallel to one another. In such an arrangement, the elongate supports preferably extend along the elongate length of the support structure, such that the support structure is strongest along its longest length.

The plurality of spaced elongate supports may be interconnected by means of one or more strengthening members. Such strengthening members may be located at an angle substantially perpendicular to the elongate supports, such that a single strengthening member may contact a plurality of substantially parallel elongate supports, thereby retaining the spacing of the elongate supports relative to one another and contributing to the strength of the overall support structure.

One strengthening member may be used. Alternatively, a plurality of strengthening members may be used along the elongate length of the support structure of the apparatus.

In one embodiment, the apparatus has a substantially circular cross-section. However, it will be appreciated that the sleeve-like form of the support structure need not necessary be circular in cross-section, but instead could be substantially square in cross-section or may be any other suitable cross-sectional shape, such as, but not limited to, triangular or rectangular.

In one embodiment, at least a portion of the translucent film is composed by a biodegradable material such as a biodegradable polymeric material or the like.

The term 'polymeric material' is intended to mean a material composed at least in part of one or more polymers.

Such biodegradable polymeric materials include, but are not limited to, thermoplastic biopolymers based on cellulose, polylactide (PLA), starch and plant- derived polyester polymers or any combination thereof. They include cellophane, polylactide (PLA), native starch, thermoplastic starch, polyhydroxybutyrate (PHB), Mater-bi, Ecoflex, Ecoflex/Pla (varied formulations), polycaprolactone (PCL), Solanyl, and any other suitable thermoplastic biomaterial known to the skilled person. Alternatively, the biomaterial may be a thermoset polymer such as Tribest S 351 or any other suitable thermoset biopolymer known to the skilled person.

It will be appreciated that the biomaterial may be a mixture of one or more of the above-mentioned biomaterials. In one embodiment, at least a portion of the support structure is composed of a biocomposite material. The use of the term biocomposites is intended to include materials composed of two or more distinct substances from natural and biological origin that are combined to produce a new material with properties not present in either individual material.

By biodegradable material it is intended to include all biocomposite and biopolymeric materials including those composed at least in part of sustainable sources and whose cycle is CO₂ neutral, completely slag-free, and are biodegradable at the end of their useful lifetime (through natural biodecomposition or combustion). Such biocomposite materials may be composed of biopolymers and biofibres. In addition, the biocomposite material may also include additives to increase the useful life-time of the biocomposite material and to enhance the properties of the tree shelter. Such additives may include, but are not restricted to, UV stabilisers, waterproofing additives, extending fillers such as wood flour, olive stones powder, wheat straw flour, rice hull ash and any other suitable extending filler known to the skilled person. Such additives may also include one or more prodegradant agents that will accelerate the degradation caused by oxygen in the atmosphere.

Alternatively, or in addition to any one of more of the extending fillers mentioned above, one or more reinforcing fillers may be included in the biocomposite material. Such reinforcing fillers include, but are not restricted to, waste paper sludge, wood fibres, jute, flax, hemp, straw and any other suitable reinforcing filler known to the skilled person.

The waste paper sludge may comprise a mixture of waste paper fibres and inorganic residues. Alternatively, the degradation-resistant coating may be a coating of patent or other similar product that makes the biodegradable material resistant to degradation caused by chemicals and/or biological agents.

A further aspect of the present invention provides a method of production of an apparatus according to a preceding aspect of the present invention comprising co- extrusion moulding of the support structure and translucent film.

Brief Description of the Drawings An embodiment of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of an embodiment of an apparatus in accordance with a first aspect of the present invention; Figure 2 is a perspective view of a first embodiment of an apparatus in accordance with a second aspect of the present invention;

Figure 3 is a perspective view of a second embodiment of an apparatus in accordance with a second aspect of the present invention;

Figure 4 is a perspective view of a third embodiment of an apparatus in accordance with a second aspect of the present invention;

Figure 5 is a perspective view of a fourth embodiment of an apparatus in accordance with a second aspect of the present invention; and

Figure 6 is a perspective view of a fifth embodiment of an apparatus in accordance with a second aspect of the present invention.

Detailed Description of the Invention

Figure 1 shows a tree shelter 10 comprising a longitudinal body composed of a biodegradable material with a first end 30 and a second end 40. A portion of the body extending from the first end 30 is coated with a film of degradation-resistant material 80 such as, for example, polypropylene or a degradation-made resistant biomaterial such as PLA, Mater-Bi, Starpol, and the alike. Thus, when the first end 30 of the tree shelter 10 is buried into the ground in use, the first end 30 is protected from premature degradation which would otherwise occur and destroy the lower part of the tree shelter 10 before the young plant is of a sufficient size to cope without the protection provided by the tree shelter 10.

It will be appreciated that although the embodiment shown in figure 1 shows the first end 30 of tree shelter 10 coated in a film of a polymeric material such as polypropylene or polylactide or a paint coating, the first end 30 could be protected by a slip-on sleeve coated in a degradation-resistant material such as polypropylene or polylactide, or a lower portion of the tree shelter body extending from first end 30 may be made completely of a degradation-resistant material fused or otherwise connected to a biocomposite material at a point of the body which would remain above ground when the tree shelter is anchored in the ground in use.

Figure 2 shows a tree shelter 10 in accordance with a first aspect of the present invention. The tree shelter 10 comprises an elongate body with a first end 30 and a second end 40 opposing the first end 30. The body is double-walled and is composed of an opaque net-like biocomposite material made of wood medium density fibres (MDF) in a matrix of polylactide (PLA) based biomaterial covered in a thin film of polylactide (PLA), a transparent biopolymeric material.

In figure 2, the whole of the tree shelter body is composed of the biopolymer coated biocomposite mesh. However, figure 3 shows a tree shelter 10 in which only a lower portion 20 i.e. a portion of the structure extending from first end 30 of the tree shelter 10 is composed of the biopolymer coated biocomposite mesh. The upper portion 20' i.e. a portion of the structure extending from second end 40 of the tree shelter 10 is composed of a biocomposite mesh, but without the biopolymer coating. In this way, the wind is prevented from accessing the interior of the tree shelter at the portion 20 of the tree shelter 10 coated in the biopolymer material and the very young plant within the tree shelter is protected from the wind. The translucent nature of the biopolymer material will allow the light to enter the interior of the tree shelter 10 through the gaps in the biocomposite mesh.

When the young plant is older and has grown to a height at which it is growing past the portion of the tree shelter composed of biopolymer coated biocomposite mesh and into the portion of the tree shelter 10 where the structure of the tree shelter 10 is composed only of the biocomposite mesh, the young plant will be of a sufficient age to withstand any detrimental effects of the wind passing through the gaps in the biocomposite mesh. In addition, as the biopolymer coating is no longer present, more light will be available to the growing young plant through the gaps in the biocomposite mesh, thus assisting in the healthy growth of the young plant, whilst still providing a protective environment for the young plant from being crushed or eaten by animals.

Figure 4 shows a further embodiment of a tree shelter 10 in accordance with the present invention in which the body of the tree shelter 10 is composed of a plurality of hollow elongate supports 50. These supports 50 serve to strengthen the tree shelter. Further strengthening is provided by the coating of a biopolymeric material. The elongate supports 50 are composed of opaque biocomposite material and are co-extruded with a translucent or transparent biopolymer film. One or more horizontal supports 60 may be optionally provided (as shown in figure 4), which interconnect with one or more elongate supports 50.

In figure 4, the whole of the tree shelter body is composed of the co-extruded biopolymer coated biocomposite supports. However, figure 5 shows a tree shelter

10 in which the lower portion 70 i.e. a portion of the body extending from first end 30 of the tree shelter 10, is composed of a solid biocomposite material that is optionally coated with a thin biopolymeric film to increase and control the time to complete biodegradation and resistance to the elements of nature, The upper portion i.e. a portion of the body extending from second end 40 of the tree shelter 10 is composed of the series of elongate biocomposite supports 50 co-extruded with a biopolymer film as detailed above.

Figure 6 shows a further embodiment of a tree shelter 10 in accordance with the present invention in which the upper portion of the tree shelter includes a plurality of small apertures to provide an array of ventilation holes.

It will be appreciated that the ventilation holes arrangement of the tree shelter shown in figure 6 may be included in any embodiment of a tree shelter in accordance with the present invention.

Although aspects of the invention have been described with reference to the embodiment shown in the accompanying drawings, it is to be understood that the invention is not limited to the precise embodiment shown and that various changes and modifications may be effected without further inventive skill and effort. For example, the tree shelters produced in accordance with the present invention may be subject to a waterproof treatment, such as the addition of polyhydrogenomethylsiloxane (PHMS) or silanes such as, for example, triethoxymethyl silanes and other such waterproofing agents to improve the durability of the biocomposite material. In addition or alternatively, animal repellents may be added to the tree shelter structure composition to provide additional protection for the young plant against damage resulting from animals. Similarly, fungi and bacteria repellents may be added to provide additional protection for the young plant against damage caused by fungi and bacteria.

Claims

1. Apparatus for protecting a young plant, the apparatus comprising a longitudinal sleeve member with a first end for insertion into the ground and a second end located at the opposing end of the longitudinal sleeve member to the first end, and a protective element located at the first end and extending at least partially along the sleeve member, the protective element comprising a coating of degradation-resistant material.

2. Apparatus according to Claim 1, wherein the degradation-resistant material is one or more materials selected from the group consisting of polypropylene (PP), high density polyethylene (PE), low density polyethylene (PE), polyvinyl chloride (PVC), and polyester (PET) film.

3. Apparatus for protecting a young plant, the apparatus comprising a longitudinal sleeve member with a first end for insertion into the ground and a second end located at the opposing end of the longitudinal sleeve member to the first end, wherein the portion of the longitudinal sleeve at and adjacent the first end comprises a first biodegradation-resistant material and at least a portion of the second end of the sleeve comprises a second material which is less resistant to degradation than the biodegradation- resistant material.

4. Apparatus according to Claim 3, wherein the second material is a biodegradable material.

5. Apparatus according to any preceding Claim, wherein the longitudinal sleeve member comprises a plurality of apertures where the apertures are filled with a translucent material, the sleeve member allowing the passage of light there through.

6. Apparatus according to claim 5, wherein at least a portion of the film comprises a biodegradable material.

7. Apparatus according to Claim 5 or Claim 6, wherein the support structure is in the form of a mesh.

8. Apparatus according to Claim 6, wherein the support structure is in the form of a plurality of spaced apart elongate supports.

9. Apparatus according to Claim 8, wherein the elongate supports are hollow.

10. Apparatus according to Claim 8 or Claim 9, wherein the plurality of spaced apart elongate supports are substantially parallel to one another.

11. Apparatus according to any preceding Claim, wherein the substantially sleeve-like form is substantially circular in cross-section.

12. Apparatus according to any one of Claims 6 to 9, wherein the substantially sleeve-like structure is substantially square in cross-section.

13. Apparatus according to any preceding Claim, wherein at least a portion of the translucent film is composed of a biodegradable material.

14. Apparatus according to Claim 13, wherein the biodegradable material is any one or more materials selected from the group consisting of: biopolymers based on: cellulose, polylactide (PLA), starch and naturally produced polyesters.

15. Apparatus according to Claim 14, wherein the biodegradable material is any one or more materials selected from the group consisting of Natureflex, polylactide (PLA), Mater-bi, Ecoflex, Ecoflex/Pla (60/40), native starch, thermoplastic starch, polyhydroxybutyrate (PHB), polycaprolactone (PCL), Solanyl, Starpol, PTP, and Tribest S 351.

16. Apparatus according to any preceding Claim, wherein at least a portion of the support structure is composed of a biocomposite material.

17. Apparatus according to Claim 14, wherein the biocomposite material comprises a combination of biopolymers and biofibres.

18. Apparatus according to Claim 16, wherein the biopolymers comprise one or more biopolymers selected from the group consisting of: cellophane, polylactide (PLA), Mater-bi, Ecoflex® Ecoflex®/Pla (60/40), native starch, thermoplastic starch Bioplast, polyhydroxybutyrate (PHB), polycaprolactone (PCL), Solanyl, Starpol, PTP, and Tribest S 351.

19. Apparatus according to any one of Claims 16 to 18, wherein the biocomposite material further comprises one or more additives selected from the group consisting of: wood flour, olive stones powder, wheat straw flour, rice hull ash, paper sludge, wood fibre, jute, flax, hemp and straw.

20. A protective sleeve for use with an apparatus according to any one of Claims 5 to 13, the protective sleeve comprising a sleeve-like structure which engages with the apparatus at one end of the support structure, at least a portion of the protective sleeve comprising a degradation-resistant element, such that in use, the sleeve is inserted into the ground with the apparatus extending from the sleeve in a direction away from the ground.

21. A protective sleeve according to Claim 20, wherein at least a portion of the protective sleeve is provided with a coating of degradation-resistant material.

22. A protective sleeve according to Claim 20 or Claim 21, wherein at least a portion of the protective sleeve comprises a degradation-resistant material.

23. A method of production of an apparatus according to any preceding Claim comprising co extrusion moulding of the support structure and translucent film.

24. Apparatus substantially as hereinbefore described and with reference to the accompanying drawings.

25. A method substantially as hereinbefore described and with reference to the accompanying drawings.