Method of Manufacturing a Plant Receptacle as well as a Plant Receptacle

Abstract

Method of manufacturing a plant receptacle wherein the following steps are performed: a) a PLA thread is co-extruded with a flexible aliphatic polyester, said flexible aliphatic polyester comprising 10 wt % to 30 wt % bamboo material, such that the flexible aliphatic polyester covers the PLA thread, thereby creating a weldable biodegradable thread; b) using said weldable biodegradable thread in a woven or non-woven process, making a permeable sheet material; continuously forming said sheet material into a continuous receptacle, by bringing the side edges of said sheet material into contact and welding said side edges together; d) cutting said continuous receptacle in predetermined lengths thereby creating separate plant receptacles.

Claims

1. A method of manufacturing a plant receptacle wherein the following steps are performed: a) a PLA thread is covered with a flexible aliphatic polyester, said flexible aliphatic polyester comprising 10 wt % to 90 wt % organic material, such that the flexible aliphatic polyester covers the PLA thread, thereby creating a weldable biodegradable thread; b) using said weldable biodegradable thread in a woven or non-woven process, making a permeable sheet material; c) continuously forming said sheet material into a continuous receptacle, by bringing the side edges of said sheet material into contact and welding said side edges together; d) cutting said continuous receptacle in predetermined lengths thereby creating separate plant receptacles or wherein said continuous receptacle is perforated substantially perpendicular to the longitudinal direction of the continuous receptacle at predetermined intervals, thereby allowing separate plant receptacles to be detached from the continuous receptacle.

2. A method of manufacturing a plant receptacle wherein the following steps are performed: a) A mix of fibres containing a first type of fibre in an amount from 25% to 75% of a monofilament PLA based fibre and a second type of fibre in an amount from 25% to 75% of a fibre made from a PLA thread covered with a flexible aliphatic polyester, said flexible aliphatic polyester comprising 10 wt % to 90 wt % organic material, such that the flexible aliphatic polyester covers the PLA thread, thereby creating a weldable biodegradable thread, said first and second types of fibres adding up to 100% of the mix; b) using said mix of fibres in a woven or non-woven process, making a permeable sheet material; c) continuously forming said sheet material into a continuous receptacle, by bringing the side edges of said sheet material into contact and welding said side edges together; d) cutting said continuous receptacle in predetermined lengths thereby creating separate plant receptacles or wherein said continuous receptacle is perforated substantially perpendicular to the longitudinal direction of the continuous receptacle at predetermined intervals, thereby allowing separate plant receptacles to be detached from the continuous receptacle.

3. The method of manufacturing a plant receptacle according to claim 1 wherein between steps c) and d) a further method step c1) is introduced wherein the formed continuous receptacle is filled with a growth medium either during or after forming of the plant receptacle, thereby creating a pre-filled plant receptacle.

4. The method of manufacturing a plant receptacle according to claim 3 wherein before step c1) or d) a pair of welding cams creates a weld across the cylinder substantially perpendicular to the longitudinal direction of the cylinder.

5. The method according to claim 1 wherein the sheet material is formed and welded around a conical former, thereby creating conical plant receptacles.

6. The method according to claim 1 wherein the PLA thread is co-extruded with said flexible aliphatic polyester, said flexible aliphatic polyester comprising 10 wt % to 90 wt % organic material.

7. The method according to claim 1, wherein the flexible aliphatic polyester comprising 10 wt % to 90 wt % organic material constitutes 15% to 90% of the entire threads volume.

8. The method according to claim 1 wherein the organic material is selected between or is a mixture of bamboo, soya, coconut, flax, and/or banana, where the organic material is added to the aliphatic polyester in liquid, pulverized or granular form.

9. The method according to claim 1 wherein the PLA thread constitutes 75% by weight of the weldable biodegradable thread, and where the flexible aliphatic polyester constitutes 25% by weight of the weldable biodegradable thread, where the aliphatic polyester comprises approx. 10% PLA by weight and 10-90% organic material by weight.

Description

DESCRIPTION OF THE DRAWING

[0030] The invention will now be explained with reference to the accompanying drawing wherein

[0031] FIG. 1 schematically illustrates the inventive method of manufacturing a plant receptacle;

[0032] FIG. 2 schematically illustrates a further embodiment of the inventive method of manufacturing a plant receptacle;

[0033] FIG. 3 schematically illustrates a plant receptacle and a cutting or seed;

[0034] FIG. 4 schematically illustrates a further embodiment of the inventive method of manufacturing a plant receptacle; and

[0035] FIG. 5 illustrates a cross-section through a preferred thread used for the manufacture of fibres.

DETAILED DESCRIPTION OF THE INVENTION

[0036] In FIG. 1 is schematically illustrated the inventive method of manufacturing a plant receptacle. A web 1 manufactured by co-extruding a PLA thread with a flexible aliphatic polyester containing 10-90 weight percent bamboo material is being fed into a former 2. In the illustrated schematic embodiment the former 2 shapes the relative flat web into a long cylinder having an open slit facing upwards. A funnel 3 is introduced into this slit where the funnel 3 is connected to a reservoir 4 such that growth media from the reservoir 4 may be introduced into the cylindrically formed web 1.

[0037] After this the cylinder 1 filled with growth media 4 is introduced into a welding machine 5 where the two opposing sides of the web are overlapped and exposed to heating such that two sides will weld together and form what in cross-section will be a closed cylinder. As the closed cylinder 1 leaves the welding machine 5 it is introduced into the last process stage 6. This process stage may carry out either one of the following routines as indicated by the arrows 10, 11 and 12. If the process stage 6 is provided with a perforating tool, the cylinder 1 will be provided with perforations 20 across the cylinder thereby making it easy to separate single plant receptacles 30 simply by tearing them apart at the perforated lines 20.

[0038] In order for the web to be able to withstand the handling, treatment etc. it is necessary to provide a certain strength in the web. For these purposes the web shall be able to withstand tension in the longitudinal direction of the web of from 35-55 N with a maximum elongation of 2-10% (which for typical receptacles correspond to between 2 mm and 15 mm). Transversely the web shall withstand a tension of 10-30 N, with an elongation between 2 and 15% (corresponding to a typical elongation of a receptacle between 5 and 15 mm). All values listed as until/before breakage.

[0039] The material thickness shall correspond to between 10-50 grams per square metre, providing the desired characteristics as discussed above.

[0040] According to the invention it is optional to have the growth media filling station 3, 4, and in embodiments where the cylinder 1 is not filled with growth media the process step 6 may simply cut the cylindrical web into separate empty plant receptacles 30. In embodiments, however, where the formed web 1 is filled with growth media by the growth media filling station 3, 4 the cutter will cut as indicated by the arrow 12, the filled cylinder 1 into separate plant receptacles 30 which are each filled with growth media.

[0041] In FIG. 2 is illustrated a method where the web material 1 is introduced into a former 2 which former 2 shapes the web material into conical plant receptacles 31. As they leave the former 2, they may pass a filling station 4 which will introduce growth media into the plant receptacle 31. At this stage a seed or plant cutting 51 may be inserted into the growth media 52 as illustrated in FIG. 3.

[0042] In FIG. 4 is illustrated a further manufacturing process. The web material 1 is supplied on a roll. The material 1 is fed into a combined former and welding station 2, 5, where a cylinder is shaped around the filling tube 3, connected to a reservoir 4 of growth medium 4. The web cylinder 1 continues into a vacuum chamber 13. The vacuum in the chamber will suck growth medium 4 through the fill tube 3 and arrange it inside the web cylinder 1, which in this manner is ready to be cut into plant receptacle sizes. By varying the speed with which the cylinder 1 advances and/or the level of under-pressure inside the vacuum chamber the speed and compactness of the growth medium may be controlled.

[0043] FIG. 5 illustrates a cross-section through a preferred thread 40 used for the manufacture of fibres, which in turn are used for making the sheet material.

[0044] Typically the tread 40 from which the web is manufactured with good results has a thickness out of the extruder of approx. 0.6 mm, and after elongation (part of the manufacturing process) the thickness is reduced to approx. 0.2 mm providing a dtex of from 1 to 5. dtex is the unit for linear density of a continuous filament or yarn, equal to 1/10th of a tex or 9/10.sup.th of a denier, i.e. very fine treads.

[0045] The core material 41 is typically a PLA polymer tread (polylactic acid based polymer) which has thermoplastic properties, thus making it suitable for extrusion processes. The core 41 is covered with a cover layer 42. This cover layer 42 is a flexible aliphatic polyester. The cover layer 42 is co-extruded in a so-called BICO process (bicomponent). Further, the material for the cover layer is modified by adding 10 wt % to 90 wt % organic material, typically bamboo or the like (see discussion above). The addition of organic material does not reduce the weldable properties of the finished tread 40 to such a degree that it is not possible to make a sheet material suitable for the invention. On the other hand the lack of complete weldability or fusion provides a material sheet having a very good integrity, and at the same time an open mesh structure allowing oxygen and water to travel through the sheet (without transport of soil or nutrients). Furthermore, bamboo is known to work as a fungicide, and therefore natural protection of the plant saplings placed in the finished plant receptacles is provided. Also the addition of organic material further improves the biogradability of the material sheet. A weldable biodegradable thread is in this manner achieved and used for the sheet material.