AU2014201840A1 - Weed Mat - Google Patents

Abstract

A weed mat including an inner core of at least one material and an encapsulating envelope to contain the inner core wherein the inner core is not attached to the encapsulating envelope. Figure 1 Figure 2 Figure 3 Figure 4

Description

WEED MAT TECHNICAL FIELD [0001] The present invention relates to weed mats and in particular to a weed mat having advantageous properties. BACKGROUND ART [0002] There are a variety of different types of weed mat commercially available. Some commercially available mats are of a single made material and these are notoriously difficult to secure in position due to their light weight. These lightweight products are generally made from an extruded or woven plastic material that is impermeable and therefore prevents any air or water movement to and from the soil. This ultimately leads to a phenomenon known as "soil death". [0003] Other types are known that use a combination of materials. Typically the materials used are glued to each other using a variety of adhesives which in the most part are toxic to the environment. The application of many of this type of adhesive also repels or limits air and water penetration through the mats. [0004] Typically this type of product is made from a paper or cellulosic material which has a very short lifespan in the field. The only known manner in which the lifespan can be increased is to apply an adhesive to restrict the degradation of the paper or cellulosic material. The adhesive used is a generally susceptible to weakening when wet and therefore, in inclement conditions, the mat is often destroyed for its purpose. [0005] Further, these products are typically no thicker than between 1 to 2.5 mm and are formed to be only partially porous which is not conducive to the transfer of air through the mat nor is it conducive to maintaining a stable soil temperature or moisture transfer. [0006] Other materials which can be used instead of a mat may form a porous barrier such as jute, hemp, coconut and palm fibre. However these products have a major issue with the inclusion of seeds or providing a media in which seeds can germinate which then emerge from the upper surface of the mat. Mats of this type which are porous also typically allow new growth on the exposed surface of the mat which again, is not preferred. [0007] Another material type which can be used instead of a weed mat is a mulch material such as straw, hay, wood bark, recycled vegetation and the like. These materials are generally labour-intensive to spread and also have a very real possibility of introducing weeds into the area surrounding the plants which are designed to be kept weed free. Further, the application of this type of material can reduce the available nitrogen in the soil as the product breaks down. [0008] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country. SUMMARY OF INVENTION [0009] The present invention is directed to weed mat, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice. [0010] With the foregoing in view, the present invention in one form, resides broadly in a weed mat including an inner core of at least one material and an encapsulating envelope to contain the inner core wherein the inner core is not attached to the encapsulating envelope. [0011] A "weed mat" is typically an artificial device laid on top of soil preventing weeds from growing to the surface. Normally, a weed mat is located over the soil around plants that are or will grow in the area or a weed mat may be used to keep an area free of any type of plant life. [0012] The weed mat of the present invention may be continuous or not. Typically, the weed mat is manufactured in a size requiring that a number of weed mats are used to cover a particular area. Normally, the weed mat of the present invention will be available in one or more predetermined sizes. Typically, a number of weed mats according to the present invention are co-located in order to substantially cover a particular ground area which is desired to be weed free or at least minimise the number of weeds that grow in the area. Alternatively, the weed mat may be formed as a substantially continuous mat which is applied in a single substantially continuous layer such as off a roll or similar. [0013] The weed mat of the present invention may take any shape. For example, it will typically be preferred that the weed mat be a regular geometric shape. This may allow easy laying of the weed mats relative to one another to cover an area. [0014] It is preferred however that the weed mat may be shaped to provide one or more openings either within the weed mat or between weed mats to allow plants to grow through a layer of weed mat. There are a variety of different ways to accomplish this. For example, an opening may be provided within the perimeter of the weed mat and extending through the weed mat. Alternatively, one or more scallop portions may be provided in one or more edges of one or more weed mats which when placed relative to a scallop portion of an adjacent weed mat may define an opening through which a plant can grow. [0015] It is preferred that the weed mat be substantially planar. Further, it is preferred that the weed mat be flexible in order to allow the weed mat to adapt to the contour of the ground surface when laid. [0016] The weed mat may be provided with one or more attachment portions allowing a weed mat to be attached to or relative to one or more adjacent weed mats. [0017] Typically, the weed mat of the present invention provides an extended life when in the field. Therefore, it is preferred that the weed mat of the present invention be robust, particularly in situations where inclement weather may be experienced. [0018] It is further preferred that the weed mat of the present invention be at least partially porous or have at least one partially porous layer or surface in order to allow particularly air and water to move through the mat. In order to be porous, all layers of the mat will normally need to be porous. However, any upper layer will normally be less porous compared to any inner or bottom layers. The density of the material used for an upper layer will normally be higher which will decrease porosity but also assists with UV stabilisation of the product. [0019] It is preferred that the upper layer of the weed mat of the present invention be substantially UV stabilised. [0020] It is also particularly preferred that no adhesive be used in the weed mat of the present invention as adhesives have been found to have a generally deleterious effect on the soil over which weed mats of the prior art have been placed. Any other attachment mechanism can be used including stitching, ultrasonic welding or similar if desired. [0021] The weed mat of the present invention may provide an insulating effect in order to maintain a relatively stable ground temperature in the soil beneath the weed mat although this will clearly depend upon the materials used. [0022] The weed mat of the present invention will include an inner core of at least one material. Any material or combination of materials may be used to form the inner core. The particular material or materials chosen for the inner core will normally be chosen to provide one or more particular characteristics to the weed mat. However normally, the material or materials -r chosen will provide other beneficial characteristics to the soil once the weed mat is in position. [0023] Normally, the material or materials used may provide the characteristics themselves or the material or materials used may be a carrier of one or more other materials providing the characteristics desired. [0024] The material or materials may be provided in any form. For example, material or materials may be provided in any one or more of a powder form, granular form, as a particulate of any size or as one or more sheets of material. [0025] The inner core may be placed into, onto or located relative to the encapsulating envelope in any manner. However the inner core is preferably not fixed or attached in any way to the encapsulating envelope in order to allow the inner core to freely move relative to the encapsulating envelope. Therefore, the inner core material or materials will be provided loosely within the encapsulating envelope. [0026] Examples of inner core materials which may be used in any combination include manure or any other type of fertiliser including any type of bead or carrier carrying one or more fertilising or nutritive substances, paper or another cellulosic material in any form including that provided in strip or shredded form or as a paper pulp, soil wetting agents or water crystals or beads, any type of plant nutrient or additive whether provided on or in a carrier or in another form. Still further, strips or sheets of any types of material may be provided as or as a part of the inner core. [0027] In a particularly preferred embodiment, the inner core is made from palm fibres. Further, the core material may have added fertiliser, biochar, enzymes, organic acids and/or beneficial bacteria. [0028] The weed mat of the present invention also includes an encapsulating envelope to contain the inner core. Preferably, the encapsulating envelope may be closed or sealed in order to encapsulate the inner core after the inner core material or materials are located in, on or relative to the encapsulating envelope. [0029] The encapsulating envelope may be left open or a portion may be left open but will typically be closed or sealed to prevent the loss of the inner core material through any opening. [0030] Preferably, the encapsulating envelope is formed from at least one layer of material provided to containing the inner core material or materials. According to a particularly preferred embodiment, an upper layer and a lower layer are provided which are joined to one another, typically about a perimeter thereof in order to form a void inside to receive the inner core material or materials. Normally, the upper layer and lower layer are joined to one another entirely about the perimeter thereof. [0031] Any suitable method can be used to join the upper layer to the lower layer of the encapsulating envelope. Preferred methods include heat sealing or an ultrasonic technique. [0032] Conventionally available ultrasonic techniques can be used to cut, sew, and seal synthetic materials, such as nylon, polyester, polyethylene, polypropylene, urethanes, and PVC, generally as long as they have at least a 60% thermoplastic composition. Material structure can vary and woven and non-woven material, knits, coated materials, laminates, and films can all be ultrasonically processed. [0033] A particularly preferred method is ultrasonic welding which is an industrial technique whereby high-frequency ultrasonic acoustic vibrations are locally applied to workpieces being held together under pressure to create a solid-state weld. It is commonly used for plastics, and especially forjoining dissimilar materials. It is preferred according to the present invention that the different preferred layers, namely the upper and the lower layer, are formed of different materials in order to provide different properties. [0034] Any material may be used for the encapsulating envelope and particularly for the upper and/or lower layers but preferably, each of the layers is at least partially biodegradable. In order to control the degradation or the life time in the field of the mat of the present invention, the degradation of the encapsulating envelope may be a delayed degradation (adjusted through material selection) or alternatively, a trigger may be required in order to begin the degradation process. [0035] Typically, a plastic or polymer material is preferred for each of the layers of the encapsulating envelope. In particular, a biopolymer is preferred. Polylactic acid or polylactide (PLA) is a thermoplastic aliphatic polyester derived from renewable resources, such as corn starch, tapioca roots, chips or starch, or sugarcane and which is preferred for at least one of the layers of the encapsulating envelope of the present invention. [0036] According to an alternative preferred embodiment, the upper layer of the encapsulating envelope will be or include UV stabilised, nonwoven polypropylene or similar and the lower layer will typically be of non-UV stabilised nonwoven polypropylene.

[0037] It is preferred that the at least one of the layers is permeable but normally all of the layers are permeable. At least one of the layers may be formed having an open grid appearance or structure or alternatively, at least one of the layers can be a continuous unbroken sheet. [0038] The encapsulating envelope of the present invention may be formed in any manner and according to any method. For example, the preferred upper and lower layers may be attached to one another about their respective edges leaving an opening into a void formed between two layers. The inner core can then be inserted into the void through the opening and then the opening can be closed. Alternatively, the inner core material or materials may be placed on an upper surface of one of the layers and then the second layer can be overlaid on the first layer. The respective edges of the upper and lower layer can then be attached to one another in order to form the encapsulating envelope. [0039] In a particularly preferred embodiment, the upper and lower layers may be attached to one another defining an opening into or through the weed mat. It is particularly preferred that a cruciform opening be formed through the weed mat. According to a preferred embodiment, a cruciform opening is formed through the weed mat by joining the upper and lower layers to one another about the edges of a cruciform shaped opening formed into both the upper and lower layers. [0040] The weed mat of the present invention can be any colour. Some colours may have advantages with stimulating or promoting plant growth. Other materials may reflect heat or light or absorb heat or light as required. Two particularly preferred colours for a combination of these advantages are light green and pink. The upper layers may be coloured and the lower layer may not be as it will normally be the upper layer which provides the advantages in stimulating or promoting plant growth because of the wavelength of light which is reflected from the upper surface to the plant. [0041] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention. [0042] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge. BRIEF DESCRIPTION OF DRAWINGS [0043] Various embodiments of the invention will be described with reference to the following drawings, in which: [0044] Figure 1 is a schematic illustration of a first preferred embodiment of the present invention. [0045] Figure 2 is a schematic illustration of a second preferred embodiment of the present invention. [0046] Figure 3 is a plan view of a preferred shape of weed mat according an embodiment of the present invention. [0047] Figure 4 is a plan view of a preferred shape of weed mat according an embodiment of the present invention. [0048] Figure 5 is a plan view of an upper side of a particularly preferred embodiment of weed mat according to the present invention. [0049] Figure 6 is a plan view of a reverse side of the embodiment illustrated in Figure 5. [0050] Figure 7 is an isometric view of a weed mat according to an alternative embodiment of the present invention. DESCRIPTION OF EMBODIMENTS [0051] According to a particularly preferred embodiment of the present invention, a weed mat is provided. [0052] In the preferred embodiments illustrated, the weed mat 10 includes an inner core of at least one material and an encapsulating envelope to contain the inner core wherein the inner core is not attached to the encapsulating envelope. [0053] Normally, in use, the weed mat 10 is located over the soil between plants that are or will grow in the area or they may be used to keep an area free of any type of plant life. [0054] The weed mat of the preferred embodiment is manufactured in a size requiring that a number of weed mats are used to cover a particular area, with the weed mat available in one or more predetermined sizes and/or shapes. A number of weed mats according to the present invention are co-located in order to substantially cover a particular ground area which is desired to be weed free or at least minimise the number of weeds that grow in the area.

0 [0055] The preferred embodiment will typically be a regular geometric shape, such as the rectangular mat illustrated in Figures 1 and 2. This will allow easy laying of the weed mats relative to one another to cover an area. [0056] However the weed mat may be irregularly shaped, such as that illustrated in Figure 3, or alternatively one or more openings can be provided either within the weed mat or between weed mats to allow plants to grow through a layer of weed mat. According to the example illustrated in Figure 4, scalloped portions 11 are provided at the corners of a weed mat 10 which when located relative to a scalloped portion of an adjacent weed mat define an opening through which a plant can grow. [0057] It is preferred that the weed mat be substantially planar. Further, it is preferred that the weed mat be flexible in order to allow the weed mat to adapt to the contour of the ground surface when laid. [0058] The weed mat includes an inner core of at least one material. Any material or combination of materials may be used to form the inner core. The particular material or materials chosen for the inner core will normally be chosen to provide one or more particular characteristics to the weed mat. [0059] The inner core may be placed into, onto or located relative to the encapsulating envelope in any manner. In the embodiment illustrated in Figure 1, the inner core material 12 has been placed onto an upper surface of the lower layer 14 and then the upper layer 13 is overlaid on the first layer. The respective edges of the upper 13 and lower layer 14 can then be attached to one another in order to form the encapsulating envelope. [0060] Alternatively as illustrated in Figure 2, the encapsulating envelope can be formed by attaching the upper 13 and lower layer 14 to one another about their respective edges leaving an opening 15 into a void formed between two layers. The inner core 12 can then be inserted into the void through the opening 15 and then the opening 15 can be closed. [0061] The inner core is preferably not fixed or attached in any way to the encapsulating envelope in order to allow the inner core to freely move relative to the encapsulating envelope. Examples of inner core materials which may be used in any combination include manure or any other type of fertiliser including any type of bead or carrier carrying one or more fertilising substances, paper or another cellulosic material in any form including that provided in strip or shredded form or as a paper pulp, soil wetting agents or water crystals all beads, any type of plant nutrient or additive whether provided on or in a carrier or in another form. Still further, strips or sheets of any types of material may be provided as or as a part of the inner core. [0062] Any suitable method can be used to join the upper layer to the lower layer of the encapsulating envelope. Preferred methods include heat sealing or ultrasonic welding. [0063] Any material may be used for the encapsulating envelope and particularly for the upper and/or lower layers but preferably, each of the layers is at least partially biodegradable. In order to control the degradation or the time in the field of the mat of the present invention, the degradation of the encapsulating envelope may be a delayed degradation or alternatively, the trigger may be required in order to begin the degradation process. [0064] Typically, a plastic or polymer material is preferred for each of the layers of the encapsulating envelope. In particular, a biopolymer is preferred. Polylactic acid or polylactide (PLA) is a thermoplastic aliphatic polyester derived from renewable resources, such as corn starch, tapioca roots, chips or starch, or sugarcane and which is preferred for at least one of the layers of the encapsulating envelope of the present invention. [0065] According to an alternative preferred embodiment, the upper layer of the encapsulating envelope will be or include UV stabilised, nonwoven polypropylene or similar and the lower layer will typically be of non-UV stabilised nonwoven polypropylene. [0066] According to the particularly preferred embodiment illustrated in Figures 5 and 6, the upper layer 13 and lower layer 14 are attached to one another using ultrasonic welding defining an opening through the weed mat. In this embodiment, a cruciform opening 20 is formed through the weed mat by joining the upper 13 and lower layers 14 to one another about the edges of a cruciform shaped opening formed into both the upper and lower layers. [0067] As best illustrated in Figure 6, the cruciform opening 20 is accessible through an elongate opening 21 in the side edge of the mat that extends to the substantially centrally located cruciform opening allowing the mat to be positioned about the stem or trunk of a plant or tree by moving the portions adjacent to the opening or by sliding the weed mat laterally about the stem or trunk so that the stem or trunk is received within the cruciform opening. [0068] In the embodiment illustrated in Figure 7, the weed mat is substantially continuous but divided into a series of cells each of which has a border which at least partially separates the inner core material in a first cell from the inner core material in a second cell. As illustrated, one or more openings are provided in the weed mat. It is particularly preferred that an opening is provided at a vertex between adjacent cells. An opening may be provided at each vertex but I "I preferably, the openings will be spaced apart from one another according to the requirements of the plants to be planted. The openings may be formed in the mat by providing a frangible line or lines at the vertex allowing a user to form openings as required using the frangible lines and according to the spacing that the user requires. Normally, spaced apart lines of ultrasonic welding are provided and one or more frangible lines are formed between spaced apart lines of ultrasonic welding. Alternatively, a user may form an opening between the spaced apart lines of ultrasonic welding as required using a knife or similar. [0069] In the present specification and claims (if any), the word 'comprising' and its derivatives including 'comprises' and 'comprise' include each of the stated integers but does not exclude the inclusion of one or more further integers. [0070] Reference throughout this specification to 'one embodiment' or 'an embodiment' means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases 'in one embodiment' or 'in an embodiment' in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations. [0071] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.

Claims (22)

1. A weed mat including an inner core of at least one material and an encapsulating envelope to contain the inner core wherein the inner core is not attached to the encapsulating envelope.

2. A weed mat as claimed in claim 1 wherein the mat is applied in a single substantially continuous layer.

3. A weed mat as claimed in claim 1 or claim 2 wherein the weed mat is modular such that a number of weed mats are co-located in order to substantially cover a particular ground area which is desired to be weed free or at least minimise the number of weeds that grow in the area..

4. A weed mat according to any one of the preceding claims wherein the weed mat is a regular geometric shape.

5. A weed mat according to any one of the preceding claims wherein the weed mat is shaped to provide one or more openings either within the weed mat or between adjacent weed mats to allow plants to grow through a layer of weed mat.

6. A weed mat according to any one of the preceding claims wherein the weed mat is substantially planar and flexible in order to allow the weed mat to adapt to contours of a ground surface when laid.

7. A weed mat according to any one of the preceding claims further including one or more attachment portions allowing a weed mat to be attached to or relative to one or more adjacent weed mats.

8. A weed mat according to any one of the preceding claims wherein the mat is at least partially porous.

9. A weed mat according to any one of the preceding claims wherein the mat has at least one partially porous layer or surface in order to allow air and water to move through the mat.

10. A weed mat according to any one of the preceding claims wherein an upper layer of the mat is less porous compared to any inner or bottom layers.

11. A weed mat according to any one of the preceding claims wherein an upper layer of the weed mat is substantially UV stabilised. I /

12. A weed mat according to any one of the preceding claims wherein the inner core is formed from one or more materials to provide other beneficial characteristics to the soil once the weed mat is in position.

13. A weed mat according to any one of the preceding claims wherein the inner core is formed from one or more materials used as a carrier of one or more other materials providing beneficial characteristics.

14. A weed mat according to any one of the preceding claims wherein the inner core is formed from one or more materials from the group including palm fibres, manure, fertiliser including any type of bead or carrier carrying one or more fertilising or nutritive substances, paper or another cellulosic material in any form including that provided in strip or shredded form or as a paper pulp, soil wetting agents or water crystals or beads, any type of plant nutrient or additive whether provided on or in a carrier or in another form, biochar, enzymes, organic acids and/or beneficial bacteria.

15. A weed mat according to any one of the preceding claims wherein the encapsulating envelope is closed or sealed in order to encapsulate the inner core after the inner core material or materials are located in, on or relative to the encapsulating envelope.

16. A weed mat according to any one of the preceding claims wherein the encapsulating envelope includes at least one upper layer attached to at least one lower layer about a peripheral area to form an encapsulating envelope without the use of adhesives.

17. A weed mat according to claim 16 wherein heat sealing or ultrasonic welding is used to attach the at least one upper layer to the at least one lower layer.

18. A weed mat according to any one of the preceding claims wherein at least one upper layer and at least one lower layer is at least partially degradable.

19. A weed mat according to claim 18 wherein the degradation of the encapsulating envelope is be a delayed degradation adjusted through material selection.

20. A weed mat according to claim 18 wherein a trigger is required in order to begin the degradation process.

21. A weed mat according to any one of the preceding claims wherein at least one upper layer is coloured stimulate or promote plant growth.

22. A weed mat according to any one of the preceding claims wherein at least one opening is formed in or between weed mats to allow a plant to grow through or between weed mats.