GB2350083A

GB2350083A - Sheet material made from recycled plastic

Info

Publication number: GB2350083A
Application number: GB0009347A
Authority: GB
Inventors: Hannah Greenaway
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-04-27
Filing date: 2000-04-14
Publication date: 2000-11-22
Anticipated expiration: 2020-04-14
Also published as: GB2350083B; GB0009347D0; GB9909629D0

Abstract

Sheet material (6, figure 2) comprises recycled plastics, preferably used polythene bags 3, which is produced by compression moulding the recycled plastics. Preferably, the polythene bags 3 are arranged in layers, and the sheet material may be built up in successive layers which are each subjected to heat and pressure between two heated plates 1,4. The appearance of the sheet material may be enhanced by using dyes and/or ensuring that specific elements, eg of a specific colour, are located on the surface when the polythene bags are arranged in their layers. The heated plates 1,4 may be provided with a protective coating 2,5, eg glass or Teflon (RTM).

Description

2350083 SHEET MATERIAL The present invention relates to sheet material

fo--.med from 5 recycled products.

During recent years, concern has continued to increase in relation to the disposal of waste products and the associated environmental pollution.

In this regard, waste products can be difficult and 'hence expensive to dispose of, particularly if they are toxic and could lead to pollution. This is exacerbated where the waste products are not readily biodegradable and therefore rem.ain as a hazard in the environment for a significant amount of time.

Commonly disposed of waste products that are non-biodegradanlee include plastics. Large amounts of waste plastic materals are continually disposed of into the environment, for examT...e into landfill sites. As biodegradation does not occur readily, the plastics remain in the environment, w i t h associated problems of pollution. Moreover, waste plastics create a hazard for wildlife whereby the plastics can ensnare, poison, choke and/or suffocate animals which encounter it. Further, waste plastics in the environment are visually unappealing.

Whilst such waste plastics may be burnt to dispose or them, this undesirably releases toxic gases into the atmosphere.

An object of the present invention is to seek to overcome such problems.

According to a first aspect of the present invention, there is provided sheet material comprising recycled plastics. Preferably, the sheet material comprises polythene in the form of recycled polythene bags. Plastics, in the f orm of polythene bags are one of the most common forms of waste product that is difficult to dispose of. Recycling them into a usable sheet material significantly reduces the burden of waste disposal.

In preferred embodiments the sheet material comprises transparent packaging plastics.

Other polymer based films suitable for use in the invention have previously been used for packaging purposes, such as plastic carrier bags, dry-cleaning protective sleeves and binbags.

The sheet material may be configured to take advantage of the colour and/or design of the original plastic product to determine its final appearance. For example, green polythene th black lett bags w. -ering would give rise to greensheet material with distorted black letter based designs. Sheet material adapted to comprise packaging plastics may be semi transparent and have a wax-like appearance. The visual characteristics of the original plastics material can hence be used to good effect in producing an attractive end sheet material.

Preferably, the thickness of the sheet material is variable 30 from lmm and 3mm. The sheet material can as such be cut using conventional scissors or craft-knives. The thinner versions of the sheet material can be torn, folded and rolled. The sheet material may further be used as a paper or cardboard substitute whilst the thicker versions may be used for construction purposes.

Conveniently, the sheet material may further comprise one or more dyes. In preferred embodiments, the sheet material comprises layered and overlapping recycled plastics elements subjected to heat and pressure.

According to a further aspect of the present invention there is provided a method of producing sheet material, comprising subjecting recycled plastics to heat and pressure.

Conveniently, the method comprises the steps of:

1) arranging a plurality of separate recycled plast-cs elements into an overlapping layered configuration; and 2) subjecting the layered configuration to heat and pressure.

-e o- T, combined effect of heat and pressure alter the stat f the separate elements so that they can fuse together to form an integral sheet.

A Transfer Heat-Press apparatus is preferred for the above method. The size of Transfer Heat-Press used determines the surface area of the sheet material. To produce larger shee--s, larger Transfer Heat-Press's may be used or alternatively separate sheets of sheet material can be heat-sealed together using apparatus such as an iron. In this connection, heat may be applied to the area of the join to melt/seal the sheets together, without the requirement of any further means of adhesion.

In preferred embodiments, the method of producing sheet material further comprises the step of dying some or all of the recycled plastics elements prior to arrangement in the overlapping layered configuration. R vat may be used for this purpose and may vary in size from for example a saucepan to an industrial fabric dye vat.

Preferably, the heating and pressing of the recycled plastics elements is performed at one of: 200'C for 40 seconds, 150'C for 50 seconds or 250'C for 20 seconds. These parameters have been found particularly suitable.

Conveniently, the step of arranging the overlapping layered configuration includes presenting specific elements at a surface of the sheet material for information and/or decorative purposes. The specific elements may for example 15 comprise lettering or pictures.

Preferably, the sheet material is built up as a plurality of successive layers, the layers being subjected to heat and pressure.

By building up the layers successively, a more detailed and controlled decoration can be achieved. In this way, an appearance of depth can be afforded to the sheet and the likelihood of distortion of the decoration is reduced.

Preferably, the method further incorporates the use of a vacuum press. A vacuum press can be used to mould the sheet material into particular shapes thereby increasing the versatility and applications of the invention.

Conveniently, the method incorporates a heat press, the pressing surfaces (plates) of which may be provided with a protective coating, for example of glass or Teflon (Trade Mark). One or both of the plates of the press may be heated (hot-plates).

Such a protective coating protects the hot-plate or plates of the Transfer Heat-Press from direct contact with the melting plastics material. Baking parchment may be used as a substitute for the Teflon (Trade Mark) or glass coating.

In order that the invention may be clearly understood and readily carried into effect, an example thereof will now be described with reference to the accompanying drawings in which:- Figures 1 and 2 show schematically an embodiment in accordance with the present invention.

With the present invention, two plates 1, 4 of a heat press (shown schcmatically) are used to produce sheet material from recycled plastics materials 3. A lower plate 4 may be provided in the form of a plywood tray configured to hold 1cose materials in place.

Plastics materials 3, which may comprise any suitable plastics, for example recycled polythene bags, are arranged on a protective sheet 5 provided on the plate 4. Where recycled polythene bags are used, they are layered 1-n an even configuration approximately five plastic bags thick or equivalent, across the protective sheet present on the plate 4. The protective sheet may be glass coated or have a coating of Teflon (Trade Mark). Using around five plastics bags layered on top of each other will ultimately result in sheet material of around 1 mm thick.

-ics materials individually typically have The recycled plast dimensions significantly smaller than those of the sheet material being formed and any gaps present in the layers of polythene bags may produce holes. If holes are not desired no gaps in the layers should be present. This may mean arranging each layer of polythene bags to ensure coverage of any holes present in the layer below. The layers should also be free from knots, pieces of paper, string or other material which may be attached to the recycled polythene.

The layered polythene bags 3 should then be covered by a further sheet of protective coating 2 again glass coated or formed of, for example, Teflon (Trade Mark) At th-Ls stage pressure can be applied manually to the layered materials to dispel- some of any trapped air within the layers.

The heated plate 1 is then brought into contact with the layered materials and pressure is applied to bring the plates 1, 4 together. The reuuisite compression of the layered polythene material 3 by the plates 1,4 can be mechanically assisted, for example with the aid of an air compression system, which may be formed as part of the heat press. Also, the pressure applied to the plates 1, 4 may be varied by the air compression system.

The sheet material 3 can be built up in successive pressing steps, so that successive layers of recycled plastics material are added to the sheet material and then subjected to heat and pressure.

Whilst the preferred protective coating for the plates of the press is Teflon (Trade Mark) or glass, alternatives such as baking parchment, are possible. Whilst in this examiDle on' v the top plate 1 is heated, the bottom plate 4 could also be heated.

The temDerature of the hot plate or plates 1,4 ideally ranges - can be used from 0-250 degrees centigrade. A thermostal o control the tem3Derature at which the hot plate(s) are set.

Heating and pressing of the recycled plastics elements i s performed at one of: 200'C for 40 seconds, 150'C for 50 seconds or 250'C for 20 seconds, although 200'C for 40 seconds has found to be most efficient.

Between the plates 1,4, the polythene is simultaneously melted 15 and compressed. A timer (not shown) may be used to control how long the plate(s) remain in contact with the TD1astics material.

The sheet material thus produced 6 should be left to cool, 20 before removing the protective coatings 2,5 from both surfaces.

In order to produce sheet material of approximately 3mm thickness, twelve layers of polythene bags or equivalent are layered upon the plate 4 instead of five as discussed above.

The recycled plastics materials can be dyed prior to subjecting them to heat and pressure. To dye a quantity of, for example, polythene sheeting 2 metres square, the polythene sheeting is added to a dye vat containing about 9 litres of water. The solution is boiled and dye and acid are added. To ensure an even coating of dye on the plastic, the dye powder is diluted in a small jug of water before adding to the dye vat. For example, 15m1 of dye is added to 100m1 of water. Direct dyes dissolve at 35 degrees, so that the water in which the dye is dissolved should be at approximately 35 degrees. The acid is used at a dilution of 20% acid to 80% water. The dye solution and 25m1 of diluted acid are added to the vat contents.

Dying a completed sheet of sheet material may cause the 'ves material to become distorted as the dye process invol 10 heating the polythene.

-he solution for The plastics needs then to be boiled in t between 10 minutes to 1 hour. The polythene is then removed from the dye vat and rinsed in clean water. It must be completely dry before it is layered on the plate 4.

It is possible to repeatL pressing of the sheet material many times until the desired affect is obtained. More decorative layers can be added at each press. The colours and decorative marks distort and converge differently with every press of the 1% plates.

When using a single heated plate, it is often advisable to turn the finished sheet over once it has been pressed and then repeat the melting process so that each side has been pressed by the heated plate. This generally assists in ensuring a smooth finish on both sides. It is preferable in this event to remove all of the protective coatings 2 5 from the polythene and replace them. This avoids any pronounced indentation in the final product which may occur when the protective coating is used more than once.

For a sheet of sheet material comprising polythene and dye, it is necessary to protect the dyed surface on either side by applying with heat and pressure one or two layel-s of undyed clear polythene e.g. transparent polytLhene. This in effect laminates the dyed surface.

When heating and pressing the recycled plastics elements, an advantageous addition to the production process of the present invention, although not essential, is an air extraction system. In this respect, the fumes produced por-entially can. 10 be damaging to health.

It will be understood that the above is a description of a preferred embodiment only and that variants are possible within the scope of the invention.

The sheet material of the present invention has meny advantages. It is lightweight, strong, wear-resistant, durable, flexible, mouldable, waterproof, readily bondable to itself and other materials, easily decorated and makes use of 20 a waste product.

These qualities make it highly suitable for numerous applications, including inter alia a packaging material, a construction/building material and a paper/cardboard 25 substitute.

Claims

1. Sheet material comprising recycled plastics.

2. Sheet material as claimed in claim 1, wherein the sheet material comprises polythene.

3. Sheet material as claimed in claim 11 or 2, comprising recycled polythene bags.

4. Sheet material as claimed in any one of claims 1, 2 or 3, comprising transparent packaging plastics.

5. Sheet material as claimed in any preceding claim, wherein the thickness of the sheet material is variable from lmm and 3mm.

6. Sheet material as claimed in any preceding claim further comprising one or more dyes.

7. Sheet material as claimed in any preceding claim comprising layered and overlapping recycled plastics elements subjected to heat and pressure.

8. A method of producing sheet material, comprising subjecting recycled plastics to heat and pressure.

9. A method of producing sheet material as claimed in claim 8, comprising the steps of:

1) arranging a plurality of separate recycled plastics elements into an overlapping layered configuration; 2) subjecting the layered configuration to heat and pressure.

10. A method of producing sheet material as claimed in claim 9, further comprising the step of dying some or all off the recycled plastics elements prior to arrangement in the overlapping layered configuration.

11. A method of producing sheet material as claimed in claims 9 or 10, wherein the heating and pressing of the recycled plastics elements is performed at 200'C for 40 seconds.

12. A method of producing sheet material as claimed in any one of claims 9 to 11, wherein the step of arrangJnq the overlapping layered configuration includes presenting specific -mation elements at a surface of the sheet material- Lror infoand/or decorative purposes.

13. A method of producing sheet material as claimed in any one of claims 9 to 12, wherein the sheet material is bz,-'Llt up iii successive layers, each subjected to heat and pressure.

14. A method of producing sheet materiall as claim-2d 4n any one of claims 9 to 13, wherein the method inco-rpo-ra--es a vacuum press.

15. A method of producing sheet material as claimed in any one of claims 9 to 14, wherein the method incorporates a heat press, the plates of the heat press each being provided with a protective coating.

16. A method of producing sheet material as claimed in claim 15 wherein the protective coating comprises glass coated or Teflon (Trade Mark) material.

17. A sheet material substantially as hereinbefore described 4 1 - 12 with reference to the accompanying drawings.

18. A method of producing a sheet material substantially as hereinbefore described with reference to the accompanying 5 drawings.