Self-supporting plugs and other structures for use in plant production

Abstract

In the present invention a method for manufacturing a self-supporting structure used in germination of seeds and plants growth and a process for producing the same is presented. The self-supporting structure is obtained by mixing a growth medium with a binding agent, which is solely or mainly a fibrous material. In preferred embodiments, the fibrous embodiment is biodegradable. The invention discloses a process wherein the growth medium and the binding agent are mixed followed by shaping into the desired dimension of the self-supporting structure.

Claims

1. A self-supporting structure used for germinating seeds and plant growth and which comprises a growth medium constituted of a plurality of singular constituents, where each of the singular constituents are bonded to one or other constituents by a binding agent and where the binding agent is a fibrous material.

2. The structure according to claim 1, where in the amount of binding agent is maximally 30% by weight related to the weight of the growth medium.

3. The structure of claim 1 wherein the binding agent is biodegradable or partly biodegradable such as, but not restricted to, poly ethylene glycol, poly--caprolactone, poly lactic acid, modified poly lactic acid, poly hydroxyalkanoate, hemp, flax, coconut fibres, naturally occurring fibres with examples being cotton and silk, naturally occurring fibres coated with one or more types of polymer, starch and starch based fibres, cellulose, celluose based fibres such as lyocell and viscose, fibres consisting of carbohydrate monomers, dimers or oligomers such as sucrose and co-polymer fibres of mixtures of non-biodegradable and biodegradable components or fully biodegradable components.

4. The structure of claim 1 wherein the binding agent is dyed fibres.

5. The structure of claim 1 wherein the binding agent is a mixture of more types of fibres selected from fibres such as poly ethylene glycol, poly--caprolactone, poly lactic acid, modified poly lactic acid, poly hydroxyalkanoate, hemp, flax, coconut fibres, naturally occurring fibres with examples being cotton and silk, naturally occurring fibres coated with one or more types of polymer, starch and starch based fibres, cellulose, celluose based fibres such as lyocell and viscose, fibres consisting of carbohydrate monomers, dimers or oligomers such as sucrose, co-polymer fibres of mixtures of non-biodegradable and biodegradable components or fully biodegradable components, polyamides, polyurethanes, some types of polyester such as poly ethylene tetraphalate and co-polymers of non-biodegradable components.

6. The structure according to claims 1 and 5 where the binding agent consists of at least 50% poly lactic acid or modified poly lactic acid, more preferably at least 70%, most preferably at least 80% by weight related to the weight of the binding agent

7. The structure according to claims 1 and 5 wherein the binding agent completely or partly is comprised by a fibrous material fully or partly comprised by or coated with one or more components requiring the addition of a curable to obtain the desired properties as a binding agent where the curable can bind to either the fibrous material or to the fibrous material and the growth medium and the curable can contain one or more of the following reactive chemical groups: amines, imines, carboxylic acids, thiols, and oxiranes.

8. The structure according to claim 1 where the binding agent consists of fibres with a denier value below 40, more preferably below 25 as this reduces the amount of fibrous material required to obtain a self-supporting structure.

9. The structure according to claim 1 wherein the binding agent is comprised by more than 50% by weight of a fibrous material and by less than 50% of another binding agent that can be a liquid, slurry or solid at ambient temperature which can consist of the same chemical components as the fibrous part of the binding agent as well as other components that chemically differ from that or those of the fibrous part of the binding agent with examples being polyurethane, poly vinyl ethylene and poly vinyl alcohol.

10. A method of preparing a plug according to claim 1 where the fibrous binding agent and the growth medium are mixed followed by shaping into the shape of a structure being either a plug, mat, block, pot or similar.

11. A method of preparing a plug according to claim 10 where the fibrous binding agent and the growth medium are mixed by hand followed by shaping into the shape of a structure being either a plug, mat, block, pot or similar.

12. A method according to claim 10 wherein the mixing of the growth medium and the binding agent is carried out at a temperature between 0-50 C., preferably 10-30 C.

13. A method of claim 9 wherein the growth medium and the binding agent are added to a container and mixed through stirring with one or more stirrers that are made from or coated with a material with surface tension preferably below 40 dyn/cm, more preferably below 35 dyn/cm.

14. A method according to claim 9 where the growth medium and the binding agent are mixed in a wet state by applying jet streams followed by drying and shaping of the mixed growth medium and binding agent or alternatively followed by shaping and drying.

15. A method of claim 10 where the growth medium and binding agent are provided in dry or neutral humidity state and are mixed in a chamber by applying air convection through the chamber].

Description

[0030] In another embodiment of the invention as shown in FIG. 1, the self-supporting plug is produced by having the growth medium 1 and the binding agent 2 in a container 3 that can be completely closed or have one or more openings 4 or one or more open sides 5 or alternatively combinations hereof. In the container one or more stirring devices 6 are positioned. The stirring device can attain various geometries and is preferably made from or coated with a material with a low surface tension such as poly tetrafluoro ethylene or silicone. The surface tension of the material used to produce the stirrer or the coating on the stirrer is preferably below 40 dyn/cm, more preferably below 35 dyn/cm to prevent adherence between the stirrer and the growth medium and binding agent. The growth medium and the binding agent are mixed by rotating the stirrer inside the container until a cohesive structure between the growth medium and the binding agent is created. Afterwards the structure obtained after mixing the growth medium and the binding agent is shaped into the desired dimension to form a self-supporting structure.

[0031] In an alternative embodiment, the growth medium and the binding agent are present in a container. Water is preferably added to the container to wet the growth medium and the binding agent and the growth medium and binding agent are mixed through jet streams or other means of introducing movement within the container as known to those skilled in the art. When the growth medium and binding agent have been adequately mixed, said mixed material is dried and formed into the desired dimension. In another embodiment, the said mixed material is formed into the desired shape followed by a drying procedure. The drying is by applying heat, pressure reduction, centrifugation or combinations hereof. The drying step is preferably preformed by means of centrifugation.

[0032] In a further embodiment of the invention, the growth medium and the binding agent are present in dry or neural humidity state in a container as the growth medium and binding might be in such states as-received. By applying pressurised air into the container through nozzles or other arrangements as know to those skilled in the art, the growth medium and the binding agent inside the container are brought into movement. Through the movement, the growth medium and the binding agent are mixed. Following the mixing, the mixed material is shaped in to the desired dimension.