GB1587864A - Capillary matting - Google Patents

Description

(54) AN IMPROVED CAPILLARY MATTING (71) We, LANTOR INTERNATIONAL LIMITED, a British company of St.Helens Road, Bolton BL3 3PR, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to improvements in irrigating growing seeds or plants by the use of capillary matting. Such matting is used to hold and spread water evenly from a source to plants growing in a growing medium in pots or containers which are placed on the matting.

Hand watering of pot plants and shrubs is a laborious and skilful task when applied on a large commercial scale, and for many years new methods have been devised and attempts made to reduce the labour input by use of mechanical or automatic devices.

Irrigation of container grown stock outdoors, or in polythene tunnel houses, typically involves the use of overhead sprinklers or spraylines but the efficiency of such systems is questionable. Even with large number of spraylines or sprinklers to cover the bed areas on which the nursery stock is standing, a high proportion of the water is wasted. Certain areas of plants can be too far from or too near to the water source and are therefore outside the water's span. Good water distribution has long been recognised as an important contribution to the efficiency and performance of commercial growing enterprises.

The water-holding capacity of the substrate on which the containers are standing is very important when considering irrigation problems. Gravel, for example, will isolate the container from the water but sand will allow some uptake of water into the container by capillary action.

An early method of irrigation was by use of a so-called capillary bed i.e. a system of irrigating plants from below by means of capillary rise of water from a bed of sand provided with a constant water table. A simple system to apply water (and nutrients) is by having trickle hose lines or similar methods laid on top of a layer (typically 1"-2" depth) of sand.

However, such a system does have certain disadvantages such as the expense of construction - for outdoor and polythene tunnel houses this involves constructing beds to contain the sand and ensuring that the sand layer within the beds is perfectly level. For indoor or glasshouse use the main disadvantage of a sand bed is the weight of the sand used which means that very strong bench supports are needed to support the weight of sand.

Again there is the need of an absolutely level surface.

A number of irrigation systems using non-woven materials or mattings have been introduced which rely on the capillary action of the non-woven fibrous matting. With suitable mattings high water-holding capacities are achieved, and the water will travel along or upwards by capillary suction action and can enter the container to replace that which is taken in by the plant.

Suitable non-woven capillary mattings have the advantage of being light in weight and easy to lay. They are able to wet out readily and can have high water-holding capacity.

After use at the end of a growing season the containers are removed, the mattings are allowed to dry. brushed clean and rolled up and stored for later use. Or they may be simply dried, cleaned and re-used again.

One difficulty which arises in the use of capillary mattings (and sandbeds) is the growth of algae, and even moss, liverworts or lichen on the exposed surface of the wet matting. Algae infestation is particularly prevalent when the matting is in use in warmer humid atmospheres, particularly when the matting is used for indoor use such as a glass house.

Such growths reduces the properties of the matting to hold and spread water - particularly if the matting is allowed to dry out. It can also reduce and even eliminate capillarity if it gets beneath the containers. It can also use up plant foods and trace elements which have been added to the water to promote the growth of plants.

Tending and cropping of plants when the matting is wet can become hazardous if the operative has to walk on the surface of the wet matting, since the presence of algae growth presents a very slippery surface. Visual appearance of algae on a matting also give the plot an 'uncared' for appearance.

The control and minimisation of algae growth is, therefore, very important for successful and efficient use of a capillary matting system for the irrigation of seeds and plant in a growing medium in a container. One typical solution is the use of algicides which are chemicals such as quaternary ammonium compou'nds applied in solution form to the matting but there are problems associated with the application and use of these materials.

Thus, for example direct application of algicide solution to the surface of affected areas of matting can be done by spraying but this needs care for some plants in that overspraying of algicide on to leaf growth can damage certain plants. Algicides could of course be put into the water supply but this tends to be wasteful and not really practical - most watering systems are direct from mains supply and would require a metering device to regulate the algicide dosage. If moreover, the matting is used in outdoor application, then obviously an algicide treatment runs the risk of being wasted away by downpour of rain.

We have observed that algae growth on the surface of objects such as rocks, stones and pebbles was evident when such objects were in damp or wet surroundings such as stagnant pools of water, and was particularly in evidence on smooth surfaced rocks or pebbles. We have also noted that algae growth was inhibited, or was absent, when the surface of an object was dry or rough surfaced or dark coloured and even more so when the object was of a red colour.

It has also been observed that known non-woven capillary mattings, when used as an irrigation medium for the growing of pot plants and the like, display algae growth on their upper surfaces particularly when the matting is made from white or light coloured fibres.

Dark coloured mattings show less algae growth.

We have found that by providing a non-woven fibrous matting with a layer of an open-celled flexible foam on the upper surface of the matting and using this as a capillary matting irrigation system for plants and seeds in containers then the incidence of algae contamination is much reduced.

According to the present invention a method of watering plants or seeds growing in a growing medium within a container is provided which comprises placing the container in contact with a moist two-layer capillary matting. the lower layer of the matting consisting of a non-woven fabric having high-water holding and water-spreading properties and the upper layer consisting of a flexible foam of plastics material or rubber.

The matting may have additional layers. For example there could be a bottom layer of impermeable plastics sheet or there could be more than one layer of non-woven fabric under the foam.

In accordance with this invention the matting may be kept moist by. for example, trickle hose pipes laid on to the matting at intervals.

The capillary matting of the present invention is more resistent to the growth of algae when in use as a water-holding and water-spreading means since the exposed surface of the foam layer of the matting when in use remains relatively dry even after saturation of the matting with water. Water tends to drain from the surface of he foam layer down into the non-woven fabric layer which acts as the water reservoir. When a plant container containing the growth medium and plant is placed on the surface of the foam the weight of the container and contents compresses the foam immediately below the container and brings into close proximity the water filled matting and the base of the container and allows capillary uptake of water into the growing medium.

Examples of synthetic rubbers that may be used for the foam are stvrene butadiene.

polychloroprene. polyvinylchloride or vinyl chloride copolymers and polyurethane rubbers.

The preferred foam material is a polyurethane of the polyether type since it offers better resistance to acid and to degradation by light and heat than polvester urethane foam.

The foam layer may for example be formed in situ on the non-woven matting but it may be applied as a preformed sheet material and bonded to the non-woven matting by means of an adhesive binder. Thus a non-woven fibrous web may be deposited onto a sheet of polvurethane foam and the web/foam combination may be immersed in an adhesive binder mix. the excess of the binder mix is removed bv suction extraction and the web/foam combination is then passed through a hot air drier to dry and cure the binder and effect lamination of the foam to the non-woven fibrous web.

The foam layer may be colourless but is preferably coloured red, black or green. We have found it particularly advantageos to use a red coloured polyether urethane foam layer.

The colouring may for example be added as a pigment to the foam-forming material or to the adhesive binder used to bond the foam to the non-woven fibrous web.

Thickness and density of the foam layer varies according to the desired application. A foam thickness of 2 mm. is preferred but a range of 1 mm. to 5 mm. is sensible in that below 1 mm. there would not be much cushioning and above 5 mms there would be no advantage in terms of the cost of the foam related to the benefits it brings to the matting.

The non-woven fabric layer may be for example any known non-woven capillary matting but it is preferably a random laid fibrous web in which the fibres have been chemically bonded, needle punched or thermobonded.

The fibres of the web can be for example either synthetic or natural fibres or mixtures of synthetic and natural fibres but are preferably a mixture of woollen fibres and synthetic fibres.

The adhesive binder for the fibres can be for example any natural or synthetic rubber which will withstand chemical breakdown when used in the matting but is preferably based on a styrene-butadiene rubber.

Example A randomly laid web comprising a mixture of wool, viscose rayon, acrylic, nylon and cotton staple fibres in the ratio of 60:20:7.5:7.5:5 parts by weight was produced at a weight of 300 g.s.m. on a Rando Webber web forming machine ("RANDO" is a Trade Mark).

This unbonded fibrous web was laid onto the surface of a red coloured polyether urethane foam of 2 mm. thickness, weight 36 g.s.m. The foam and web combination was passed through a bath of a latex binder of the following composition: "Revinex 9042" - 286 parts by weight "National 125-2812" - 146 parts by weight Zinc Oxide (50% disp.) - 30 parts by weight "Coptal OS 20" - 25 parts by weight Water - 702 parts by weight ("REVINEX" is a Trade mark).

Revinex 9042 (Revertex Limited) is a carboxylated styrene butadiene latex supplied as a 53% solids dispersion; National 125-2812 (National Adhesives and Resins Limited) is a self reactive vinyl acetate copolymer latex supplied as a 45% solids dispersion; Coptal OS 20 (Alliance Dye and Chemical Co. Limited) is a sodium dioctyl sulphosuccinate wetting agent.

The foam and web combination saturated with the latex binder was passed over a vacuum extraction slot where excess binder was removed to a level where the wet pick up was 160% of the foam and web weight. Speed through the machine was 4.5 metres per minute and the fabric was dried and cured by passage through a forced air drying oven at 1800C for 4 minutes. The finished fabric had a weight of 426 grams per sq. metre.

A roll of the matting produced as described above and measuring approximately 20 metres x 1.5 metres was laid on to a level area of ground on a polythene tunnel house with a sheet of an impermeable material - a polythene film sheet slightly larger in size than the matting being interposed between the matting and the ground. The red foam layer of the matting was uppermost. The matting was then thoroughly saturated with water and a number of 6 inch diameter polythene plant plots containing a suitable growing medium and Dwarf Rhodedendrons (Type Praecox) were distributed over the surface of the matter (16 pots per sq. metre). Regular irrigation of the plant crop was carried out over the subsequent growing period by means of trickle hose pipes laid onto the matting at intervals.Water from the pipes soaked into the matting via the foam layer and was taken up by the plant roots as required.

The crop was removed after a period of approximately 7 months when it was noted that the foam surface of the matting exhibited virtually no algae growth or contamination. Any lose debris (e.g. twigs, leaves. growing medium) present on the matting was easily removed by use of a soft brushing action.

A control matting. produced in the same manner as the product of the invention but without the foam layer, and used alongside under the same conditions as the above displayed algae growth which required vigorous scraping and brushing for removal. and treatment of the matting with an algicide before the matting could be re-used.

WHAT WE CLAIM IS: l. A method of watering plants or seeds growing in a growing medium within a container which comprises placing the container in contact with a moist two-layer capillary matting, the lower layer of the matting consisting of a non-woven fabric having high

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   The foam layer may be colourless but is preferably coloured red, black or green. We have found it particularly advantageos to use a red coloured polyether urethane foam layer.

   The colouring may for example be added as a pigment to the foam-forming material or to the adhesive binder used to bond the foam to the non-woven fibrous web.

   Thickness and density of the foam layer varies according to the desired application. A foam thickness of 2 mm. is preferred but a range of 1 mm. to 5 mm. is sensible in that below 1 mm. there would not be much cushioning and above 5 mms there would be no advantage in terms of the cost of the foam related to the benefits it brings to the matting.

   The non-woven fabric layer may be for example any known non-woven capillary matting but it is preferably a random laid fibrous web in which the fibres have been chemically bonded, needle punched or thermobonded.

   The fibres of the web can be for example either synthetic or natural fibres or mixtures of synthetic and natural fibres but are preferably a mixture of woollen fibres and synthetic fibres.

   The adhesive binder for the fibres can be for example any natural or synthetic rubber which will withstand chemical breakdown when used in the matting but is preferably based on a styrene-butadiene rubber.

   Example A randomly laid web comprising a mixture of wool, viscose rayon, acrylic, nylon and cotton staple fibres in the ratio of 60:20:7.5:7.5:5 parts by weight was produced at a weight of 300 g.s.m. on a Rando Webber web forming machine ("RANDO" is a Trade Mark).

   This unbonded fibrous web was laid onto the surface of a red coloured polyether urethane foam of 2 mm. thickness, weight 36 g.s.m. The foam and web combination was passed through a bath of a latex binder of the following composition: "Revinex 9042" - 286 parts by weight "National 125-2812" - 146 parts by weight Zinc Oxide (50% disp.) - 30 parts by weight "Coptal OS 20" - 25 parts by weight Water - 702 parts by weight ("REVINEX" is a Trade mark).

   Revinex 9042 (Revertex Limited) is a carboxylated styrene butadiene latex supplied as a 53% solids dispersion; National 125-2812 (National Adhesives and Resins Limited) is a self reactive vinyl acetate copolymer latex supplied as a 45% solids dispersion; Coptal OS 20 (Alliance Dye and Chemical Co. Limited) is a sodium dioctyl sulphosuccinate wetting agent.

   The foam and web combination saturated with the latex binder was passed over a vacuum extraction slot where excess binder was removed to a level where the wet pick up was 160% of the foam and web weight. Speed through the machine was 4.5 metres per minute and the fabric was dried and cured by passage through a forced air drying oven at 1800C for 4 minutes. The finished fabric had a weight of 426 grams per sq. metre.

   A roll of the matting produced as described above and measuring approximately 20 metres x 1.5 metres was laid on to a level area of ground on a polythene tunnel house with a sheet of an impermeable material - a polythene film sheet slightly larger in size than the matting being interposed between the matting and the ground. The red foam layer of the matting was uppermost. The matting was then thoroughly saturated with water and a number of 6 inch diameter polythene plant plots containing a suitable growing medium and Dwarf Rhodedendrons (Type Praecox) were distributed over the surface of the matter (16 pots per sq. metre). Regular irrigation of the plant crop was carried out over the subsequent growing period by means of trickle hose pipes laid onto the matting at intervals.Water from the pipes soaked into the matting via the foam layer and was taken up by the plant roots as required.

   The crop was removed after a period of approximately 7 months when it was noted that the foam surface of the matting exhibited virtually no algae growth or contamination. Any lose debris (e.g. twigs, leaves. growing medium) present on the matting was easily removed by use of a soft brushing action.

   A control matting. produced in the same manner as the product of the invention but without the foam layer, and used alongside under the same conditions as the above displayed algae growth which required vigorous scraping and brushing for removal. and treatment of the matting with an algicide before the matting could be re-used.

   WHAT WE CLAIM IS: l. A method of watering plants or seeds growing in a growing medium within a container which comprises placing the container in contact with a moist two-layer capillary matting, the lower layer of the matting consisting of a non-woven fabric having high

   water-holding and water-spreading properties and the upper layer consisting of a flexible foam of plastics material or rubber.
2. 2. A method as claimed in claim 1 in which the foam is in the form of a sheet.
3. 3. A method as claimed in claim 1 or 2 in which the foam is a polyurethane foam.
4. 4. A method as claimed in claim 1, 2 or 3 in which the foam is black, green or red.
5. 5. A method as claimed in any of claims 1 to 4 in which the foam has a thickness of about 2 millimetres.
6. 6. A method as claimed in any of claims 1 to 5 in which the non-woven fabric is a random layered non-woven fabric wherein the fibres have been chemically bonded, needle punched or thermobonded.
7. 7. A method as claimed in claim 6 in which the fibres are bonded by a styrene-butadiene rubber.
8. 8. A method as claimed in any of claims 1 to 7 in which the non-woven fabric is a mixture of woollen and synthetic fibres.
9. 9. A method as claimed in any of claims 1 to 8 in which the matting has at least one further layer.
10. 10. A method of watering plants or seeds substantially as herein described with reference to and as illustrated in the Example.