COVER SHEET

Field of the Invention

This invention relates to a cover sheet which has application in many different environments , including cover sheets for the ground to improve soil and plant quality, covers for swimming pools and other liquid reservoirs , covers for the ground upon which concrete will be laid, and elsewhere.

Background of the Invention

Most cover sheets which are used to provide a cover either on the ground, on water or in other environments, generally comprise a sheet of material which is merely intended to be laid on the ground. The material can be flexible or rigid depending on the application so that it can be rolled or otherwise moved. In most instances, little regard is had for the environment beneath or around the cover sheet, except for perhaps in swimming pool applications where swimming pool covers are known to provide some heat insulating qualities .

Summary of the Invention

The object of the present invention is to provide a cover sheet which can be used in a number of different environments and which improves the environment surrounding or covered by the sheet so as to improve a characteristic of the environment or the atmosphere or soil quality covered by the cover sheet.

The invention may be said to reside in a cover sheet comprising : a layer of material; a plurality of projecting portions projecting outwardly from the layer in a first direction; and at least some of the projections which are to be adjacent an article to be covered by the cover sheet

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having at least one aperture to enable water and/or air to circulate through the aperture .

The formation of the projections provides some insulating qualities to the cover sheet and the apertures allow air and/or water to penetrate the cover sheet to the environment covered by the cover sheet to thereby improve the environment around the cover sheet or the article to be covered by the cover sheet, such as soil or a body of water .

In one embodiment of the invention a plurality of second projections project outwardly from the layer in a second direction opposite the first direction.

In one embodiment of the invention, the layer is formed from a single web and the first and second projections are formed in the single web and the first and second projections are open projections defining open internal spaces.

In another embodiment of the invention, the layer is formed from two webs which are joined together with the first projections being formed by deforming the first web and the first projections being closed by the second web, and the second projections are formed by deforming both the first and second webs so the second projections are open.

Preferably the first projections have different heights.

In one embodiment third projections are formed in the second web and extend in the same direction as the second projections, the third projections being closed by the first web.

Preferably the first and second projections are

substantially circular and are defined by an end wall and a peripheral side wall .

Preferably the at least one aperture comprises a first aperture in the end wall of at least some of the second projections and a second aperture in the peripheral side wall of at least some of the second projections.

Preferably some of the first projections include an aperture in the peripheral side wall of the first projections .

In one embodiment of the invention the projections extend only in one direction and are formed from some closed projections and some open projections, the open projections forming a well for receiving water and the open projections having the aperture, the aperture being formed by a stem portion which extends outwardly away from the projection to come into contact with the article which the cover sheet is to cover so that water which forms in the open projections is drawn through the stem by a wicking effect to the article .

The invention may also be said to reside in a method of forming the above-mentioned cover sheet, comprising: passing a web between a pair of rollers, the rollers having projecting portions and/or cavity portions to form projections; and forming apertures in at least some of the projections.

In one embodiment the projections which have the apertures are formed by a plug having a concave opening and a hollow tube extending outwardly of the concave opening so that the hollow communicates with the concave opening, and applying vacuum to the hollow member so that the material layer is pulled by vacuum down into the hollow member to

tear the layer and form the stem.

In another embodiment the apertures may be formed after the projections are formed at a punching station.

In another embodiment of the invention, the passing of the web between a pair of rollers may form first and second projections which project in opposite directions with respect to one another.

In one embodiment the method comprises passing a single web through the rollers for forming the first and second projections from the single web.

In a second embodiment the method comprises passing first and second webs through the rollers and forming first projections in the first web by deforming the first web, and second projections in both the first and second webs by deforming both the first and second webs .

The invention in a further aspect may also be said to reside in a method of forming a cover sheet, comprising: forming a plurality of projections in a web so that the projections project outwardly of the web, and wherein at least some of the projections are open projections _/ and forming an aperture in at least some of the open projections with the aperture having a stem which projects outwardly of the open projections so that the stem can come into contact with an article when the cover sheet is laid on an article so that water which collects in the open projection is drawn by a wicking effect through the aperture to the article.

Preferably the method includes forming a plurality of closed projections.

In one embodiment the open projections and closed projections extend in the same direction.

Preferably the method comprises forming the open projections in first and second webs which overly one another .

Preferably the closed projections are formed between the first and second webs .

The invention also provides a cover sheet comprising: a layer of material ; the layer being formed from plastics material mixed with fibrous material .

Preferably the fibrous material is sugar cane or rice hull.

Preferably the plastics material is provided in the form of plastic grindings .

The fibrous material may be provided in the form of grindings or larger fibres .

A further aspect of the invention may be said to reside in a sheet material comprising: a first sheet member having a plurality of closed bubbles, and a plurality of open projections having an open end and a hole opposite the open end so air can flow through the hole and out of the open end; a second sheet member located against the first sheet member; and a plurality of apertures through the second sheet member so the air can escape from between the first and second sheet members through the apertures to atmosphere.

Preferably the first sheet member and the second sheet

member are attached together by stitching so the second sheet member locates against the first sheet member, and preferably the apertures are formed by holes created by the stitching of the first and second sheet members .

A further aspect of the invention may be said to reside in a sheet material, comprising: a first sheet member having a plurality of closed bubbles, and a plurality of open projections having an open end and a hole opposite the open end so air can flow through the hole and out of the open end; and a second sheet member located against the first sheet member .

In one embodiment a plurality of apertures are provided through the second sheet member so the air can escape from between the first and second sheet members through the apertures to atmosphere .

The projections are preferably conical or part spherical in shape .

Brief Description of the Drawings

Preferred embodiments of the invention will be described, by way of example, with reference to the accompanying drawings in which :

Figure 1 is a cross-sectional view of a cover sheet according to one embodiment of the invention taken along the line I-I of Figure 2 ; Figure 2 is a plan view of a cover sheet according to one embodiment of the invention;

Figure 3 shows the formation of a cover sheet according to one embodiment of the invention;

Figure 4 is a cross-sectional view along the line IV-IV of Figure 5 of a second embodiment of the invention;

Figure 5 is a plan view of the cover sheet according to the embodiment of Figure 4;

Figure 6 is a drawing of components for fitting to a roller for forming open projections according to another embodiment of the invention;

Figure 7 is a side view of a cover sheet formed according to the method of Figure 6 ;

Figure 8 is a view of a first sheet material used in the preferred embodiments of the invention;

Figure 9 is a more detailed view of the sheet material of Figure 8 ; Figure 10 is a view of a second sheet material used in the preferred embodiment of the invention;

Figure 11 is a more detailed view of the sheet material of Figure 10 ; and

Figure 12 is a view of a sheet member formed from the first and second sheet members of Figures 8 and 9.

Detailed Description of the Preferred Embodiments With reference to Figures 1 and 2 , a cover sheet 10 is shown which comprises a layer 12 preferably formed from plastics material which may be generally rigid material or flexible material . The layer 12 in the embodiment of Figures 1 and 2 is formed from two webs 12a and 12b (see Figure 3) as will be defined in more detail hereinafter.

A plurality of first projections 16 are formed in the layer 12 and project in a first direction outwardly of the general plane of the layer 12. A plurality of second projections 18 are formed in the layer 12 and project outwardly in a second direction opposite the first direction .

In the embodiment shown in Figures 1 and 2, the first projections 16 are formed by deforming the first web 12a with the second web 12b closing the projections 16 at 12b ¹ shown in Figure 1.

The second projections 18 are formed by deforming both of

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the layers 12a and 12b so that the second projections 18 are open, as is clearly shown in Figure 1.

Third projections 20 are provided which are similar to the first projections 16 but which project in the opposite direction and are formed by deforming only the web 12b with the web 12a closing the projections 20.

The second projections 18 are provided with first apertures 22 in the form of small holes in base wall 19 of the aperture 18 and a second aperture 24 in the form of a small hole in peripheral side wall 23 of the projection 18.

The first projections 16 are also formed from a peripheral wall 25 and an end wall 27.

Figure 3 shows an apparatus and method for forming the cover sheet 10 according to Figures 1 and 2. The apparatus comprises a pair of rollers 40 and 42. The roller 40 is provided with recesses 41 and projections 43. The roller 42 is provided with recesses 45 and 49. The recesses 41, 45 and 49 and projections 43 are provided with lines 44 which supply suction and the periphery of the projections 43 and recesses 41, 45 and 49 are provided with heating elements (not shown) .

Webs 12a and 12b are supplied from rolls of web material 13 and 15 and pass via guide rollers 47 to nip 48 of the rollers 40 and 42.

As the webs 12a and 12b pass between the rollers 40 and 42, the webs 12a and 12b are heated and suction supplied to the recesses 41 form the projections 16 and suction supplied to the recesses 49 and the engagement of the recesses 49 with the projections 43 form the second projections 18. The third projections 20 are formed by

the recesses 45.

Peripheral heaters about the periphery of the recesses 41, 45 and 49 and projections 43 form a heat seal which joins the webs 12a and 12b together about the periphery of the respective projections 16, 18 and 20 to thereby connect the webs 12a and 12b. The rollers 40 and 42 are also heated and this facilitates the joining of the webs 12a and 12b to form the layer 12.

The apparatus shown in Figure 3 also includes a punching station 60 in which the holes 22 and 24 are formed. The punching station 60 is operated sequentially to punch the second projections 18 after the webs 12 and 14 have hardened to form the cover sheet 10.

The cover sheet 10 can then be cut to any desired length at a cutting station 62.

The width of the cover sheet 10 shown in Figure 2 is simply exemplary and typically the width would be somewhat greater than that shown with the pattern of the projections 16, 18 and 20 repeating across the width of the sheet.

Depending on the size of the article to be covered, a number of the sheets can be joined together along their edges by heat welding or the like to form a cover sheet of the desired size.

The cover sheet shown in Figures 1 and 2 can be used to cover any articles but most preferably is intended for provision as a mulch mat for location around plants to improve soil quality and also to enable mulch located beneath the mat to decompose more quickly to provide compost and better soil quality. The cover sheet can also

be used as a swimming pool cover or cover to cover other bodies of water such as irrigation channels , heated sewerage tanks and the like.

The projections 16 and 20 generally form closed bubbles in which air is trapped. In other embodiments the humidity- inside the projections 16 and 20 may be increased and a liquid provided by forming the cover sheets in a high humidity atmosphere and by providing powdered material onto the web 12b so that when the projections 16 or 18 are formed, the humidity trapped in the bubbles formed by the projections 16 and 18 and the powdered material will result in the formation of a coloured or pigmented liquid which will tend to improve heat insulating qualities and also the amount of sunlight which passes through the cover sheet can be controlled. In still further embodiments, the webs 12a and 12b can be coated or painted various colours to regulate the heat absorption from the sun, the amount of light which passes through the cover and therefore the general heat insulating properties of the cover sheet.

The formation of a liquid or high humid atmosphere inside the projections 16 and 18 will also tend to prevent the atmosphere within those projections from becoming too hot, causing a rupturing of the projections 16 and 18 or the heat formed wells around those projections . In daytime conditions , the liquid will tend to turn into vapour because of being heated by the sun and this will also tend to keep the cover sheet well inflated. The water will condense at night and slow down heat loss through the cover sheet 10, thereby creating better insulation.

Water which falls onto the cover sheet 10 can drain through the cover sheet 10 by collecting in the projections 18 which form wells and draining through the holes 21. Water will also drain through the holes 24 if

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the water builds up to a sufficient level. The holes 21 and 24 will also allow air to pass through the cover sheet so that carbon dioxide which builds up due to aerobic decomposition beneath the cover 10 can exit through the hole 22 and be replaced by oxygen which can enter through the hole 24. Thus, water is provided to the underneath of the cover mat 10 to provide watering to the soil or to allow water to escape off the cover sheet if used as a swimming pool cover or the like into a swimming pool, and air is able to circulate from beneath the cover sheet.

Thus , the cover sheet provides for self watering of soil if used on the soil and for rain water to flow to a swimming pool or other body of water covered by the cover sheet.

The larger projections 16 shown in Figure 1 and 2 provide a spacer if two sheets are to be used one on top of the other to increase insulation and also as a support for reinforcing material or the like if the cover sheet is to be used to cover the ground beneath a poured concrete slab.

If the cover sheet is used to cover ground which in turn is to be covered by a concrete slab, an irrigation system can be provided beneath the cover sheet in the ground so that water is able to flow in the opposite direction from the ground up through the holes 21 and 24.

The ability of the sheet to allow water to flow through the sheet to the soil beneath the sheet and the retention of water under the sheet greatly improves soil condition and also the cover sheet 10 has the ability to block out light to kill weeds . If used in an environment where plants are to be planted, holes or slots can be cut in the sheet cover very easily to enable a plant to be planted in the soil and to grow and expand through the cover sheet. In some embodiments , round holes can be punched in the

cover sheet after its formation to provide locations for planting plants in the soil .

The top web 12a may be provided in different colours to provide for heat absorption between a maximum heat absorption and a maximum heat reflection to facilitate the required conditions for growing of a plant. The reflection of light back from the cover sheet 12 also improves growing conditions because a plant is illuminated not only by light shining downwardly from the sun but also being reflected back from beneath the plant.

The ability of the cover sheet 10 to provide a warm environment makes the cover sheet ideal for use on golf greens where it is desirable to elevate the temperature in winter so grass still grows on the green.

In some environments the cover sheet 10 can be used as a soil replacement so that plants can grow on top of the soil with the cover sheet replacing soil which would otherwise be provided over the plants . One such plant is the potato plant where the potatoes can grow on top of the soil under the cover sheet 10 with the cover sheet 10 blocking light but yet providing watering through the holes 21 and 24 and the improved soil conditions by virtue of the insulating effect and composting of any compost material in the vicinity of the plants . The higher temperature and therefore the humidity under the cover sheet 10 also means that the growing season will be longer .

The third projection 20 can be merely be filled with air which will provide buoyancy for environments in which the cover sheet 10 is used as a swimming pool cover or cover for other bodies of water. This will therefore tend to reduce the amount of water that sits on top of the sheet when the sheet 10 is used as a swimming pool cover.

Figures 4 and 5 show a second embodiment of the invention . In this embodiment of the invention the sheet 10 is formed from a single web such as the web 12a. The web 12a is deformed by the rollers 40 and 42 shown in Figure 3 in the same manner as previously described to form the first and second projections. Obviously, by forming the cover sheet 10 from a single web, all of the projections are open.

Thus, in this embodiment, the rollers 40 and 42 can be configured so that they are only provided with cavities and suction provided to those cavities to form the first and second projections 16 and 18.

As is shown in Figures 4 and 5, some of the second projections 18 can be provided with a dome shaped end wall 19' so that water can build up about the dome shaped end wall 19' in the projection 18 for helping in weighing the cover sheet 10 down onto the article it is to cover.

In this embodiment the larger first projections 16 may be provided with holes 71 in their peripheral side walls 25.

The embodiment of Figures 4 and 5 can also be formed by a moulding process rather than by using the technique described with reference to Figure 3.

In this embodiment the projections 16 still tend to trap hot air to thereby improve the environment of the article covered by the cover sheet 10 or the climate around the cover sheet 10. The embodiment of Figures 4 and 5 is likely to be less expensive to manufacture than the embodiment of Figures 1 and 2 and has a further advantage that cover sheets according to the embodiments of Figures 4 and 5 can be stacked by nesting one above the other.

The formation of the holes 19, 23 and 71 in the

embodiments of Figures 4 and 5, and the holes previously described in the embodiments of Figures 1 and 2 , enable small animals and insects to have access to water if the sheet is covered by water, and also to move through the cover sheet to maintain the usual insect eco-cycle over the ground or water covered by the cover sheet. Thus, the cover sheet is environmentally friendly.

Furtherstill, larger animals such as frogs and the like can drink through the holes 21 and 23 to gain access to water even though it is covered by the cover sheet. If the holes are big enough (in particular, holes 71) , frogs and the like can pass through the cover sheet and obtain some protection from cats. Furthermore, if the cover sheet covers a pond containing fish, the cover sheet can also protect the fish but still allow the fish to break the surface of the water in the vicinity of the projections 16.

Other environments for use of the cover sheet 10 include water treatment ponds to allow the water to be oxygenated underneath whilst conserving water loss, elevating the temperature to spread out bacterial treatment and maybe made a specific colour to reduce algae growth and still allow the water to run under the sheet. This may dramatically reduce the time of treating water and massively reduce the water loss which raises the concentration of solids . This cover can be used to cover open irrigation channels to allow wildlife to interact with the water while conserving water loss. Thus, the cover sheet may provide a considerably cheaper solution to preventing water loss in open channels than having to pipe those channels .

Where the cover sheet is used in conjunction with a concrete slab, the cover sheet can also raise the temperature of the concrete and make the slab waterproof,

notwithstanding that some small amount of water can pass through the openings 21 and 23. If the concrete is able to pass through the holes 21 and 23 and 71, this can increase the adhesion of the cover sheet to the concrete whilst covering the ground beneath the concrete slab and the configuration and strength which can be provided by the cover sheet 10 may also enable a reduction in the amount of concrete which is used. Any water which does pass through the holes 21, 23 and 71 can condense and return back to the soil beneath the cover sheet, thereby maintaining the water table below the concrete and preventing the area below the concrete from drying out, which may cause stresses which crack the concrete slab.

The webs 12a and 12b can be formed from various forms of plastic and may be formed from recycled material. The plastic may also include a high percentage of fibre reinforcing by fine grinding recycled or new plastic and fine grinding the fibres . For example , the fibres may be provided from sugar cane or rice hull and combined with plastic grindings and then the mixture heated and used to form the webs 12a and 12b or the plastic which is moulded if the cover sheet 10 is to be formed in a moulding processing. The addition of fibre can improve the strength of the product. The fibre can further facilitate bonding to concrete if used in combination with a concrete slab because long fibres can become embedded in the concrete to increase adhesion .

In other embodiments the material from which the layer 12 is formed may be treated with chemicals to kill unwanted bacteria and algae , and also unwanted insects . In a still further embodiment the punching station 60 may be incorporated into the rollers 40 and 42 so that the holes 21, 24 and 71 are punched concurrently with the formation of the projections 16 and 18.

Figures 6 and 7 show a still further embodiment of the invention. In this embodiment like reference numerals indicate like parts to those previously described.

In Figure 6 a component 100 is shown which is attached to a recess 45 or 49 to form open projections 18. The component 100 comprises a bowl-shaped receptacle 102 having a hole 104 which communicates with a hollow stem 106. The recesses 45/49 are the same as the recesses 45 and 49 previously described. Thus, the component 100 replaces the projections 43.

The recesses 45 or 49 are provided with a gauze (not shown) where they connect to tubes 44 (see Figure 3) . When the component 100 is used, the gauze is removed and the component 100 is fitted to the recess 45 or 49 by locating the component to the recess with tube 106 projecting into hole 110 and the lower surface 109 sitting in the recess 45 or 49.

In order to form closed projections 16 or 20 the recesses 45 and 49 shown in Figure 6 are used on their own so that when vacuum is applied to hole 110 by one of the lines 44 (for example) , the web 12b is drawn down into the recess 45 or 49, leaving the web 12a generally planar.

When it is desired to form open projection 18, the component 100 locates in the recesses 45 and 49, so that as the webs 12a and 12b move between the rollers having the component 100 (roller) 42 and roller 41 which may be formed with a cylindrical surface without projections in this embodiment. The webs 12a and 12b are sucked downwardly by vacuum onto surface 102 with the tube 106 located into hole 110 so that when vacuum is applied by line 44 to the hole 110, the webs 12a and 12b are pulled downwardly and a part of the webs 12a and 12b is sucked into the tube 106 to form stem 120. The stem 120 is

formed by the suction which pulls the material of the webs 12a and 12b downwardly and causes the material to tear after it has been pulled downwardly to thereby form the stem 120.

Because the tube 106 locates in hole 104, the diameter of the hole through which suction takes place is reduced compared to when the component 100 is not used. Thus, the pull caused by the vacuum is strong enough to pull both webs 12a and 12b against surface 102 and to tear the webs as web material is pulled into tube 106 to therefore form stem 120. Because the vacuum strength when only the recesses 45 and 49 are used is less, only one web 12b is drawn into the recess and any tendency of material to move into hole 110 is prevented by the gauze located in hole 110.

By providing the stem 120, the holes 21 will readily allow water to drain out of the open projection 18 when the cover sheet is used as a ground cover located on the ground. The reason for this is that if a small hole is punched in the projection 18, the surface tension of the water is likely to hold the water in the projection 18 and not readily allow it to drain out of the projection 18. However, by providing the stem 120 which contacts the ground, a wicking type effect is provided so that water is drawn down through the stem 120 so that it readily leaves the aperture 18 and is drained out of the aperture 18 quite quickly .

In the embodiment of Figure 7 the projections 18 and 20 project in the same direction and no opposite projections are provided.

The cover sheet of Figure 7 can be used to form a number of articles such as boxes or the like and, in particular, pizza boxes, or as a cushion protector for covering

articles, as is the case with conventional bubble wrap, so that when the pizza box or cushion material is finished with, the material can be cut so as to form a ground cover for location on the ground.

Again, the webs 12a and/or 12b can be provided with a UV stabiliser and some reflective aluminium powder or mica to reflect light back up to the foliage of plants to increase photosynthesis or the ripening of fruit. The additional light will also help reduce mould. Heat stored under the bubble and in the bubble 20 will reduce damage from frost because the heat can radiate both upwardly away from the ground and down towards the soil .

Fine rubber crumbs such as that obtained from re-grinding used car tyres can also be added to provide extra protection against heat oxidation. The rubber will also store a certain amount of heat, thereby increasing the insulation capability of the film. A fire retardant can also be added to make the matter fire barrier around the home where conventional mulch can become a fire fuel .

Figures 8 to 12 show further embodiments . Figures 8 and 9 show a sheet material 160 which is a modification to the embodiment shown in Figure 7. With reference to Figure 8, the sheet material 150 is shown in cross-section and comprises a first layer 151 and a second layer 152 which form a "bubble wrap" type sheet configuration which has a plurality of closed bubbles 153 and a plurality of projections 154 which have an open end 155 and a hole 156 opposite the open end 155. Suffice it to say the sheet material 150 is formed generally in the manner of a conventional bubble wrap type sheet material where two layers of plastic material are guided through rollers . One of the rollers has indentations for forming the bubbles 153 and vacuum is supplied to those indentations to draw the sheet material 152 away from the sheet

material 151 to form the bubbles . The structure is shown in more detail in Figure 9 with the layers being separated for the purposes of illustration. The normal forming method is modified to produce the projections 155 by providing the component 100 which has a bowl shape and a stem which locates in a corresponding shaped recess so that when vacuum is applied, both layers 151 and 152 are pulled downwardly by the vacuum and burst to form the opening 156 which also functions in the same manner as the stem 120 previously described.

The opening 156 can be level with the bottom of the bubbles 153 as shown, or could terminate above the bottom or extend below the bottom of the bubbles 153.

Figures 10 and 11 show a conventional layer of bubble wrap material 160. This material 160 is formed from layers 161 and 162 in which bubbles 163 are formed in the same manner as the bubbles 153. A further layer 164 of material is located over the bubbles 163 so that the bubbles 163 are sandwiched between the layers 161 and 164. The layer 164 may be a clear plastic layer or may be an aluminium layer, as will be described in more detail hereinafter.

Again, Figure 11 shows an enlarged view of the material 164 with the layers separated for ease of illustration.

A sheet material 165 according to a further embodiment is shown in Figure 12 and which is formed from the sheet materials 140 and 160. The sheet material 165 is formed by locating the second sheet material 160 on top of the first sheet material 150 so that the projections 154 are underneath the sheet material 150 and on the inside of the container when the top 114 is in place on the container.

The first sheet material 150 and second sheet material 160 are held together so the first sheet material 150 is

against the second sheet material 160 by stitching 170. The stitching 170 can be any conventional form of stitching and the stitching 170 forms small apertures through the material to provide an air path from beneath the sheet material 140 through the projections 154, the stitching 170 and to atmosphere, as will be described in more detail hereinafter .

The layer 164 of the second sheet material 160, when the second sheet material 160 is used to cover compost, is preferably transparent or clear plastic material.

During the composting process , water vapour will be generated which will gather on the underside of the sheet material 165 and condense. That moisture can then drop back to the composting material immediately above from where the evaporation occurred from the composting material to keep the composting material moist. The configuration of the projections 156 facilitate the dropping of the water directly back down rather than allowing the water to flow to a particular point so that the entire composting material is moistened by the return of the condensate. The sheet material 165 which is formed from the sheet materials 150 and 160 is generally transparent so that sunlight is able to pass through the sheet material 140 to facilitate heating up of the composting material and the aerobic decomposition of that material .

Whilst Figure 12 shows the materials 150 and 160 close together, because of irregularities in the materials, spaces may exist between the materials 150 and 160 which will facilitate movement of air through the sheet material 165 and out through the apertures formed by the stitching 170.

Any one or more of the webs 151, 152, 161, 162 and 164

could be coloured to act as a filter so light of a particular wavelength range passes through the webs to promote growth of plants or seedlings covered by the sheet material .

Hot air which is generated in the container during the composting process will tend to rise and pass up through the openings 156 and through the projections 154 to the boundary of the first sheet material 150 and second sheet material 160. Because the sheet materials generally locate against each other but are not adhered, air will be able to flow between the sheet materials 150 and 160 and escape through the small apertures defined by the stitching 170. Because the apertures 170 are extremely small, the apertures effectively control the escape of air out of the container, thereby reducing the tendency of the composting mass to cool.

The layer 164, when formed from clear or transparent plastic material, may be UV stabilised to prevent breakdown of the material due to sunlight.

The projections 154 are circular in plan view and have a peripheral wall portion 157 which is formed when vacuum is applied to the layers 151 and 152. The wall section 157 may form a generally conical or funnel shaped configuration, or a more semi-circular disc shaped configuration. The hole 156 is preferably much smaller in size than the open end 155 of the projections 154.

Since modifications within the spirit and scope of the invention may readily be effected by persons skilled within the art, it is to be understood that this invention is not limited to the particular embodiment described by way of example hereinabove.

In the claims which follow and in the preceding

description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise", or variations such as "comprises" or "comprising", is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.