GB2250280A

GB2250280A - Paper plant growth container

Info

Publication number: GB2250280A
Application number: GB9116652A
Authority: GB
Inventors: William Henry Hill; Kevin Patrick Tobin
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-11-27
Filing date: 1991-08-01
Publication date: 1992-06-03
Anticipated expiration: 2011-08-01
Also published as: GB9116652D0; GB9025737D0; GB2250280B

Abstract

A pot device for plants and seedlings is fabricated according to a method of manufacture which involves a two-part mould in which moist pieces of paper 2 and 3 are overlaid on the male part 10 of the mould, pressed into shape, and preferably, through a rotational and rocking motion (as shown by the arrows), the pot is formed and transferred to the female part 20 of the mould. <IMAGE>

Description

TITLE: DEVICE AND METHOD The present invention relates to a device and method for making the device, notably to a recycled paper plant growth container and to a method for moulding it from layers of paper.

BACKGROUND TO THE INVENTION: Many seedlings and plants are grown in pots which contain a growing medium. Typically such pots are made from a compressed peat so that the seedlings can be planted out without the need to remove the seedlings from the pots.

However, the use of peat is becoming ecologically unacceptable and the use of peat substitutes is desirable.

However, any substitute for the compressed peat of a flower pot must satisfy a number of requirements, in that it must have a measure of physical strength in order that the pot and its seedling can be handled, even when moist, in that the pot must be physiologically acceptable to the seedling, in that the pot must allow the seedling to be watered without becoming waterlogged, and the peat substitute must be economically attractive.

It has been proposed to make flower pots and tubs from papier mache using old newspapers. However, this is a messy process involving the shredding of the paper and the laying up of layers of the resultant paste upon a former.

We have now devised a novel form of pot made from layers of news paper which does not require the shredding of the newspaper and provides a peat substitute pot which meets the above requirements.

SUMMARY OF THE INVENTION; Accordingly, the present invention provides a pot adapted to contain a plant growth medium in which the root system of a seedling or plant can grow, which pot is characterised in that it is fabricated from separate sections of paper to provide the side wall and base sections overlapping one another and bonded together at the overlap by the application of pressure whilst wet.

The invention also provides a process for the manufacture of a pot of the invention which comprises laying up a number of sections of moist paper upon the surface of a moulding member to form each of the side and base walls of the pot, the sections of paper overlapping one another at the intersection of the side and base walls of the pot; and subsequently applying pressure to the laid up paper sections by applying a co-operating opposed mould member to the mould member carrying the laid up paper sections, whereby the laid up paper sections are caused to bond together and to transfer the pot from one mould member to the other. Preferably, the moist paper is laid up on a male mould member and the male member is caused to rotate relatively within a co-operating substantially co-axial female mould member.Transfer of the laid up paper sections from the male to the female mould member is preferably caused by rocking the male mould member about its longitudinal axis within the female mould member during rotation, whereby the line of contact between the laid up paper carried by the male mould member and the interior of the female mould member is caused to precess about the longitudinal axis of the female mould member.

Preferably, the pot has a generally frusto-conical configuration and the male mould member is pressed axially home within the female mould member and rotated therein about their common longitudinal axis to cause the laid up paper to transfer between the male and female mould members. It is preferred to provide the internal surface of the female mould with a roughened surface, for example by sand blasting or spark eroding the internal face of the mould, to assist transfer of the moulded paper from the male to the female parts of the mould. We have also found it desirable that the face of the male part of the mould opposed to the female part of the mould be provided with airways to inhibit the creation of suction at the interface between the opposed faces.Such airways can be provided by bores through the wall of the male member of the mould and/or by ribs or other raised portions on the surface of the male member which raise the moulded paper from total continuous contact with the surface of the male member.

The invention also provides the combination of a male and female mould members each having a substantially circular cross-section moulding surface, the male member being adapted to fit substantially co-axially within the female member so as to provide co-operating moulding surfaces at the interface between the two members, which mould members are relatively rotatable about their axis, the male member is configured so that it will rock within the female member when an interface of the material to be moulded is carried between the moulding surfaces.

DESCRIPTION OF THE DRAWINGS: The invention will now be described by way of illustration only with respect to a preferred form thereof as shown in the accompanying drawings in which: Figure 1 is a diagrammatic axial cross-section through a male mould member for use in the method of the invention carrying the laid up paper from which the pot of the invention is to be formed; Figure 2 is an axial cross-section through the male mould member of Figure 1 in position within its corresponding female mould member; Figure 3 is an axial cross-section through the paper pot produced by the interaction of the male and female mould members of Figure 2; Figure 4 is an axial cross-section through the male and female members of an alternative type of mould; and Figure 5 is a transverse cross-section through the moulds of Figure 4 with a paper interface between them.

DESCRIPTION OF THE PREFERRED EMBODIMENT: A pot 1, the invention, as shown in Figure 3, is preferably of a generally frusto-conical shape. However, the pot may be of other shapes which can be moulded in a two part moulding operation, for example a hexagonal tubular shape.

The pot is made from sheet waste paper, notably newspaper or the like. The pot is characterised in that it has at least two side wall layers 2 of paper which are interleaved in the area of the junction between the base and side wall of the pot with at least two layers of papers 3 forming the base of the pot. This interleaving provides a physical bonding between the side walls and base of the pot when the layers of paper are pressed together during the moulding operation described below. In order to improve the bonding of the layers of the paper and to provide a measure of strength at the lip of the pot, the upper edges 4 of the side wall layers of the paper are turned over on one another to form a double thickness rim to the pot.

The pot is of any suitable size and the paper from which it is made can incorporate plant nutrients, such as dissolved fertilisers, introduced with the water used to dampen the paper during the moulding operation. The formed pot can be given other treatments, for example it can be coated with a protective wax or the like or the wall can be apertured to assist root penetration.

The pot is formed by a moulding operation in which dampened paper sections are laid up on a male mould member. The paper sections can be of any suitable shape and preferably each wall is formed from one or more sheets each extending over at least 50%, preferably 100% of the area of the wall to be formed. This is distinguished from a papier mache operation where the paper would be shredded or mashed to provide a pulp or slurry of small portions of paper. It is preferred that those sections which are to form the side walls are of an arcuate shape and those to form the base can be of a circular or squared shape. The sections are shaped and sized so that the side wall sections can be folded over so that they extend over at least part of the base sections and vice versa. Typically, the sections overlap by from 5 to 15 mms to provide an achorage between the overlapping sections during the moulding operation.

The sections are bonded together and conformed to the desired final shape by compressing the layers together whilst moist. The desired moisture is conveniently achieved by moistening the sections of paper with water or an aqueous solution of a biodegradable adhesive, for example a polyvinylalcohol or polyvinylacetate solution, optionally also containing other ingredients, for example fungicides and/or fertilizers. The optimum extent of moistening of the paper can readily be determined by simple trial and error tests for each type of paper having regard to the need to handle the moist paper during laying up on the male mould member, the need to achieve adequate bonding and the need to produce a product which will be self supporting prior to drying. Typically, it will be sufficient to immerse newsprint paper in cold water for from 1 to 5 minutes before use.

The moist paper is laid up in the requisite layers on a frusto-conically shaped male mould member 10 by any suitable technique, for example merely by laying the moist paper onto the surface of the mould 10 or by applying it with a roller to achieve a measure of initial bonding prior to the main moulding operation.

The coated male mould member 10 is then inserted into a cooperating female mould member 20 so as to apply compression to the laid up layers between the opposed faces of the mould members. Thus, it will be preferred that the female mould member is of the same general internal shape and size as the exterior of the male mould member. Preferably, the female mould is formed as a split mould so that it can readily be removed from the male member when the moulding operation is completed. Typically, the female mould is formed in two axial halves with pins, clips or other means for locating and securing the halves of the mould together.

As indicated above, it is preferred that the internal surface of the female mould member have a roughened surface as shown schematically as the shaded area in Figure 4.

This roughening can be achieved by any suitable means, for example by sand blasting or spark eroding the face of the mould or by rubbing sand paper or other abrasive over the surface of the mould.

The mould members can be made from any suitable material, for example metal, plastic or other materials. It is preferred to form them from plastic mouldings for cost and weight considerations and the external surface of the male member of the mould may be given release or other coatings to aid release of the moulded paper from it. If desired, the walls of the moulds can have water drainage holes or the like to assist escape of excess water during the compression of the moist paper.As indicated above, it is particularly preferred that the external face of the male member of the mould be provided with means for allowing air to penetrate to the interface between the mould and the moulded paper so as to minimise the formation of a vacuum between the mould and the moulded paper which could prevent ready transfer of the moulded paper from the male member of the mould to the female mould member as the mould is separated. Such air penetration can be achieved by means of one or more axial bores or holes 40 through the transverse base 41 of the male member 42 shown in Figure 4.

Such bores are preferably located symmetrically about the longitudinal axis of the mould member, for example at 60, 90 or 120 intervals as a single or double ring of holes through the base of the mould. Alternatively, as shown in Figure 5, the outer side and/or base faces of the mould member 42 can carry axial ribs or grooves 43 which allow air to penetrate axially from the free end of the male member 42 along the interface between the moulded paper 45 and the face of the mould 42 during the separation of the mould members. As shown in Figure 5, these ribs 43 may serve to hold the adjacent areas of the moulded paper 45 clear of the surface of the mould 42 to form air passages 46 over at least part of the interface between the moulded paper and the mould.Such ribs or grooves can intersect one or more of the bores 40 through the side and/or end walls of the mould so that air need not be drawn from the free end of the mould but can be drawn through one or more of the bores.

Axial pressure is applied to cause the male and female mould members to compress the moist paper layers between their opposed moulding surfaces. As indicated above, we have found that it is desirable that the moist paper layers on the male mould member transfer to the interior face of the female mould member so that the resultant compressed pot can be readily removed when the female mould is split.

This is conveniently achieved by allowing the male mould member to rock, and preferably also to rotate, within the female member as the axial pressure is applied. This can be achieved by forming the male member with a slightly smaller included angle of taper than the female member.

Alternatively, the necessary clearance to enable rocking to take place can be achieved by the use of substantially mating male and female mould members, but taking advantage of the extra thickness of the paper at the base of the side wall of the pot (area A on Figure 2) to provide the clearance between the opposed faces of the mould members axially further up the mould.

In a particularly preferred form of the moulding operation, the male member is pushed axially home into the female member and then rotated within the female member by means of a handle 11 or a knurled axial extension 12 shown dotted in Figure 1 whilst applying a slight radial rocking motion during the rotation, as shown by the arrows in Figure 2.

If desired, the axial pressure can be applied by a screw, lever or other clamping means and the rotation imparted by a motor drive or the like. However, the moulding operation readily lends itself to manual operation so that the pots can be manufactured by an amateur gardener using waste paper or other recycled materials.

The pot produced by the moulding operation will be damp and will usually require drying before use. However, since the minimum number of paper sections are used in forming the walls and base of the pots, they are usually selfsupporting when removed from the mould whereas a papier mache pot cannot be handled until dried. The pots and method of the invention can thus readily be used by an amateur without special skills or drying equipment.

The pots can be used as such for pricking out or transplanting seedlings or for the germination of seeds.

However, it will usually be preferred to dry out the moist paper, to enable the pots to be handled and stored before use, by any suitable method, for example using a warm air stream or by standing in a warm environment overnight.

The invention provides a means for making pots from a waste material rather than from peat, but which can be used in the same manner as peat pots. The pot walls readily absorb water so that a plant growth medium within the pots can absorb water from a capillary mat or other external watering means. Alternatively, since the walls of the pots are water permeable, excess water applied directly to the plant growth medium can escape through the walls of the pots, thus reducing the risk of plant deaths or growth check through over-watering. The walls of the pots are usually root permeable and biodegradable so that the pots can be buried in the soil without the need to remove the seedlings from the pots at planting out.

The invention has been described above in terms of a moulding operation in which the moist paper is laid up on the male mould member and transferred to the opposed face of the female member during moulding. However, it will be appreciated that the moist paper can be laid up inside the female mould member and then compressed by inserting the male member into the female mould member. In this case it may not be desirable for the laid up paper sections to transfer from one mould member to the other so that the radial rocking of the male member within the female member during the moulding operation may not be required. The male mould member can be coated with or formed from a water repellant material so that pick up of the moist paper by the male member is inhibited and its face can be formed with the ribs or grooves shown in Figures 4 and 5 to reduce the formation of a vacuum at the interface between the male member and the moulded paper.

Claims

WHAT WE CLAIM IS:

1. A pot adapted to contain a plant growth medium in which the root system of a seedling or plant can grow, characterised in that the pot is fabricated from separate sections of paper to provide the side wall and base sections overlapping one another and bonded together at the overlap by the application of pressure whilst wet.

2. A pot as claimed in Claim 1 in which the pot is of general frusto-conical configuration.

3. A pot as claimed in Claim 1 or Claim 2 in which at least two sections of paper from the side wall are interleaved with at least two sections of paper from the base section.

4. A pot as claimed in any of Claims 1 to 3 in which the side wall is formed with a rim by folding-over the upper edge of the side wall.

5. A pot as claimed in any of Claims 1 to 4 in which a plant nutrient is impregnated into the paper.

6. A pot as claimed in any preceding claims in which apertures are provided to assist root penetration of the wall.

7. A process for the manufacture of a pot as claimed in any preceding claim, comprising laying up a number of sections of moist paper upon the surface of a moulding member to form each of the side and base walls of the pot, and subsequently applying pressure to the laid up paper sections by applying a co-operating opposed mould member to the mould member carrying the laid up paper sections, whereby the laid up paper sections are caused to bond together, and to transfer the pot from one mould member to the other.

8. A process as claimed in Claim 7 in which the paper is laid up on a male mould member and transferred to a female mould member.

9. A process as claimed in Claim 7 or Claim 8 in which the transfer is effected by a relative rocking motion between the mould members in a direction substantially transverse to the longitudinal axis of the mould members.

10. A process as claimed in any of Claims 7 to 9 in which relative rotational motion is provided between the mould members to cause precession of the mould member on which the paper is laid up relative to the other mould member.

11. A process as claimed in any of Claims 7 to 10 in which the paper is moistened with a biodegradable-adhesive.

12. A process as claimed in Claim 11 in which the adhesive is polyvinylalcohol.

13. A process as claimed in Claim 11 in which the adhesive is polyvinylalcohol.

14. A process as claimed in any of Claims 7 to 13 in which the paper is impregnated with a plant nutrient.

15. A process as claimed in any of Claims 7 to 14 in which the paper is impregnated with a fungicide.

16. A process as claimed in any of Claims 7 to 15 in which one of the mould members is provided with airways to assist the release and transfer of the pot to the other mould member.

17. A process as claimed in any of Claims 7 to 16 in which at least one of the mould members is formed by two mating parts.

18. A pot substantially as hereinbefore described as illustrated in the drawing and as made by a process as claimed in any of Claims 7 to 17.

19. A pot substantially as hereinbefore described with reference to the drawing.