GB2499076A

GB2499076A - Laminate comprising polyester between fused plastic layers

Info

Publication number: GB2499076A
Application number: GB1221291.6A
Authority: GB
Inventors: Philip Nicholas Stewart Dale; Sean Malachy Reel
Original assignee: ONE DELTA Ltd
Current assignee: ONE DELTA Ltd
Priority date: 2011-11-24
Filing date: 2012-11-26
Publication date: 2013-08-07
Anticipated expiration: 2032-11-26
Also published as: GB201221291D0; GB201120332D0; GB2499076B

Abstract

The laminate 1 comprises a polyester layer 13 that is bonded by adhesive layers 12, 14 between two layers 11, 15 of fused plastics. The preferred fused plastics layers 11, 15 are derived from granulated or particulate, recycled polyester, which has been heated in a mould to produce the sheet with hard outer skins and which under further heat is expanded between the skins. Preferably the polyester layer 13 is a woven fabric, especially a recycled freight trailer curtain, coated with polyvinyl chloride (PVC). A batch manufacturing process of board laminates is described. The laminates may be used in building construction, flood barriers and anti-ballistic components.

Description

1

Laminates

5 This invention relates to laminates and their manufacture.

According to one aspect of the present invention there is provided a laminate comprising a polyester sheet that is bonded by adhesive between two sheets that are each of fused plastics 10 material.

According to another aspect of the invention a method of manufacturing a laminate comprises the steps of bonding a polyester sheet by adhesive between polyester sheets that are CM 15 each of fused plastics material.

CM The sheets of fused plastics material may be sheets that

1 comprise expanded plastics material sandwiched between plastics

00 skins. The sheets may be manufactured using a process

"l~~ 20 described in EP-A-1360047, or by using a process that, in general terms, comprises the steps of: placing granulate or particulate plastics materials (for example, mixed recycled waste plastics materials) in a two-part mould which is then heated for a short period to develop a hard skin on the 25 plastics material as an outer layer; adding granulated or particulate plastics material (for example, additional mixed recycled waste plastics materials) to the mould together with a 'blowing agent' or expandable-foam plastics filler material; and re-heating the mould for a further period to produce the 30 required sheet.

Sheets of fused granulated or particulate plastics material manufactured as described in the preceding paragraph have been found to have weight and cost advantages over other materials 35 in a variety of applications, but it has been found that a product with significant strength and durability can be formed

2

according to the invention as indicated above, by lamination of the sheets with an intervening polyester sheet. Where found necessary or desirable, one or each of the sheets of fused plastics material may contain an insert, for example a wire 5 mesh or metal bar for reinforcement of the sheet.

The polyester sheet involved in the laminate and method of the present invention may be a woven polyester sheet. The polyester sheet may have a plastics coating, and more 10 specifically, this coating may be of polyvinyl chloride (PVC). Although virgin woven polyester sheets coated with PVC may be used, it has been found that side-curtains such as employed for enclosing the loads of freight vehicles, may be very satisfactorily recycled for use in the laminate according to CM 15 the present invention.

CM The laminate of the present invention has the advantage that apart from the adhesive required for bonding, it can be 00 manufactured entirely, or to a very large extent, from recycled

20 materials. It has been found to have significant strength and durability superior to comparable products of similar weight and cost, and to be lightweight, robust and versatile, and not subject to deterioration from rot or exposure to ultra-violet light. Moreover, manufacture of the laminate can readily be 25 straightforward and relatively inexpensive, and can be fully-

or partially-automated, or fully- or partially-manual.

A laminate and its manufacture, all in accordance with the present invention, will now be described, by way of example, 30 with reference to the accompanying drawings, in which:

Figure 1 is illustrative of the structure of a flat-board laminate according to the invention; and

3

Figures 2 to 12 are illustrative of successive steps in a method according to the invention of manufacturing the flat-board laminate of Figure 1.

5 Referring to Figure 1, the board 1 is a five-layer laminate that involves component layers 11 to 15 of three distinct specifications A to C, namely: a mixed-waste plastics board or sheet; an adhesive; and a polyester sheet having a PVC coating. More specifically in the present example, the component 10 specifications are:

Component specification A: a fused plastics sheet comprising expanded plastics material sandwiched between plastic skins, which is formed by powder-impression or plastics-fusion process CM 15 of mixed plastics waste - for example, high density

1 polyethylene (HDPE), high density polythene (HDP) and waste

CM electrical insulation and other materials (WEE) - as referred

"l~~ to in EP-A-1360047, in which the mixed recycled waste plastics

00 materials are entered in granulated or particulate form in a

"l~~ 20 two-part mould that is heated for a short period to develop a hard, outer skin on the plastics material, and the mould is reheated after adding further granulated or particulate plastics material together with a 'blowing agent' or expandable-foam plastics filler material (other materials, for example wood, 25 steel, paper, sand, fly-ash, ceramic and/or woven fibre may be added during manufacture);

Component specification B: an adhesive, which once set has high-flexibility, high-retention and high-impact absorption 30 characteristics, such as that marketed under the Registered Trade Mark TEROSTAT of Henkel AG & Co. KGaA, as adhesive MS 93 99; and

35

Component specification C: a high-tenacity woven polyester sheet coated in PVC - this may be material that has been previously used as a side curtain or 'taut liner' for enclosing

4

or securing the load of a freight vehicle, but may otherwise be virgin PVC-coated polyester that is 900gsm when coated, and has a tensile strength which conforms to British Standard 3424-6B N/50mm (min), a tear strength of N (min) Din 53 363 and an 5 overall flame retardancy to the Din 75200 Standard.

10

The five layers 11 to 15 of the board 1 have component specifications A to C as set out in the following table;

CM CM 00

15

20

Layer

Specification

11

A

12

B

13

C

14

B

15

A

The manufacture of the laminated board 1 will be described as typical board of a batch of boards 1 manufactured according to the manufacturing method illustrated in Figures 2-12 of the accompanying drawings.

25 Referring to Figure 2, the manufacture of each board 1 involves two sheets 21 that are drawn from respective stacks 22 and 23 of such sheets that have all been pre-formed in accordance with component specification A, for utilisation individually as the outer layers 11 and 15 of the manufactured board 1. A single 30 sheet 24 is drawn from a stack 25 of sheets complying with component specification C, for incorporation as layer 13 sandwiched between sheets 21 drawn from the two stacks 22 and 23, in the manufactured board 1.

35 Before manufacture begins, it is essential for good results that all stacked sheets 21 and 24 are clean and free from dust, grease and any other impurity which may arrest, hamper or otherwise impede the various stages of the manufacturing

5

process, and, in particular, may compromise the achievement of efficient adhesion during lamination. Sheets 21 are cleaned using an industrial liquid cleaner (for example the product marketed under the Registered Trade Mark LOCTITE by Henkel AG 5 & Co. KGaA, as industrial cleaner 7013), and then allowed to dry in a clean environment where there is no risk of dust-contamination .

Where the sheets 24 have been salvaged from freight use, they 10 are submitted initially to an industrial-cleaning process in specialist dip-tanks to free them from stubborn or ingrained grease and dirt. Each sheet 24, whether salvaged or new, is cut to the size required to leave a peripheral overhang (not shown in Figures 1 to 12) with respect to the sheets 21 in the CM 15 sandwich construction of the board 1. Once cut to rough size,

the sheets 24 are cleaned using a liquid cleaner (for example CM the product marketed under the Registered Trade Mark LOCTITE by

Henkel AG & Co. KGaA, as industrial cleaner 7 013) and then allowed to dry in a clean environment where there is no risk of 20 dust-contamination.

00

Prior to stacking, each sheet 21, which may for example measure 1220mm x 2440mm x 18mm and weigh 33kg, is subjected across the entire area of one of its top and bottom faces to treatment to 25 enhance its bonding by adhesive; the particular face involved is the top face of each sheet 21 in the stack 22 and the bottom face of each sheet 21 in the stack 23. The treatment may be a plasma treatment in which the relevant face is subjected to flame from a gas-fired nozzle, or is skimmed using a light 30 abrasive applied by brush or roller.

Two roller-conveyor beds 2 6 and 27, as shown in Figure 2, are used in succession in the manufacture of each board 1. In this respect, the stack 22 of sheets 21 is located at an input end 35 28 of the bed 26 and the stack 23 of sheets 21 is located

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alongside the bed 27. The stack 25 of sheets 24 is located alongside the bed 26.

The lamination process begins as illustrated in Figure 3 with 5 the feeding of the top sheet 21 from the stack 22 lengthwise onto the input end 2 8 of the bed 26, to be conveyed by the bed 2 6 under an adhesive spreader 2 9 at that end. The spreader 2 9 oscillates back and forth across the bed 2 6 and as represented schematically in Figure 4, spreads adhesive of component 10 specification B evenly across the top face of the sheet 21.

The adhesive is spread throughout the length of the sheet 21 as the sheet 21 is conveyed progressively along the bed 26 into the condition illustrated in Figure 5 where the sheet 21 has cleared the spreader 29. When this latter condition is CM 15 reached, a sheet 24 from the stack 25 is fed sideways and downwardly to bring its bottom face onto the adhesive-covered CM top face of the sheet 21. The sheet 24 is brought down onto the sheet 21 in register with the sheet 21 as illustrated in 00 Figure 6.

1— 20

The sheet 21, together with its superimposed sheet 24,

continues to be conveyed along the bed 2 6 to exit the bed 2 6 via a compression roller 30, as illustrated in Figure 7. The roller 3 0 presses the sheet 24 hard down onto the sheet 21 on 25 the bed 26, ensuring that the adhesive is comprehensively distributed between the contacting top and bottom faces of the sheets 21 and 24 and good bonding is achieved with the least possibility of entrapment of air.

30 From the bed 26, the superimposed sheets 21 and 24 are fed lengthwise onto the input end 31 of the roller-conveyor bed 27 to be transported by the bed 27 to enter under an adhesive spreader 32 at that end, as illustrated in Figure 8. At the same time, and as part of the batch manufacturing process, 35 adhesive is being spread from the spreader 29 onto the top face

7

10

of a second sheet 21 that has been fed from the stack 22 onto the bed 26.

The spreader 32 oscillates back and forth across the bed 27 spreading adhesive of component specification B evenly, as represented schematically in Figure 9, across the top face of the sheet 24 as the sheet 24 is being carried by the sheet 21 along the bed 27. A second sheet 24 from the stack 25 is at this time fed sideways over the second sheet 21 on the bed 26.

Once the first sheet 21 with its superimposed first sheet 24 has been moved on from the spreader 32 to the condition shown in Figure 10, a sheet 21 is fed from the stack 23 ready to be brought down onto the adhesive-covered sheet 24. At this time, CM 15 the second sheet 24 from the stack 25 has already been brought down onto the adhesive-covered second sheet 21 on the bed 26.

CM

"l~~ As shown in Figure 11, the sheet 21 from the stack 23 is

00 brought down onto the adhesive-covered sheet 24 carried by the

-1— 20 first sheet 21 on the bed 27, and bonding between the second sheet 21 from the stack 22 and its superimposed, second sheet 24 is consolidated as the two pass under the compression roller 3 0 in exiting the bed 2 6 as one.

25 The laminate comprising the first sheet 21 with its superimposed sheet 24 and the newly superimposed sheet 21, is conveyed by the bed 27 to exit the bed 27 via a compression roller 33, as illustrated in Figure 12. At this time the second sheet 21 with its superimposed sheet 24 has left the bed 30 26 ready to be entered onto the bed 27 in continuation of the batch manufacturing process. This process continues in the manner described above with further sheets 21 and 24 being drawn in turn from the stacks 22 and 25, and then further sheets 21 from the stack 23, for the build up from the roller-35 conveyor bed 2 6 onto the roller-conveyor bed 2 7 of board-

8

laminates 1 each consisting of a sheet 24 bonded by adhesive between two sheets 21.

The adhesive of each newly-manufactured board-laminate 1 exiting the bed 2 7 is allowed to dry for a minimum of two hours while the laminates are stored flat under an evenly-distributed compression force of, for example, 26kN/m2 applied via a flatbed press or by evenly-distributed weights. Once drying has been completed, the board-laminates are trimmed and cut to required size and shape, ready for use.

Board-laminates 1 as manufactured as described, may be used with advantage in the building-construction industry, for flood barriers (for example as described in GB-A-2471201) and for anti-ballistic and other protection in a security context.

Claims

Claims:

1. A laminate comprising a polyester sheet that is bonded by adhesive between two sheets that are each of fused plastics material.

2. A laminate according to Claim 1 wherein the polyester sheet is a sheet of woven polyester.

3. A laminate according to Claim 2 wherein the woven-polyester sheet has a plastics coating.

4. A laminate according to Claim 2 wherein the woven-polyester sheet has a coating of polyvinyl chloride.

5. A laminate according to any one of Claims 1 to 4 wherein the sheets of fused plastics material are sheets comprising expanded plastics material sandwiched between plastics skins.

6. A laminate according to Claim 5 wherein the expanded plastics material contains material other than plastics material.

7. A laminate according to any one of Claims 1 to 6 wherein at least one of the sheets of fused plastics material contains an insert for reinforcement of the sheet.

8. A method of manufacturing a laminate, comprising the steps of bonding a polyester sheet by adhesive between polyester sheets that are each of fused plastics material.

9. A method according to Claim 8 wherein the polyester sheet is a sheet of woven polyester.

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10. A method according to Claim 9 wherein the woven-polyester sheet has a plastics coating.

11. A method according to Claim 9 wherein the woven-polyester sheet has a coating of polyvinyl chloride.

12. A method according to any one of Claims 8 to 11 wherein the sheets of fused plastics material are sheets comprising expanded plastics material sandwiched between plastics skins.

13. A method according to Claim 12 wherein the expanded plastics material contains material other than plastics material.

14. A method according to any one of Claims 8 to 13 wherein at least one of the sheets of fused plastics material contains an insert for reinforcement of the sheet.

15. A method of manufacturing a laminate, substantially as hereinbefore described with reference to the accompanying drawings.

16. A laminate manufactured by a method according to any one of Claims 8 to 15.

17. A laminate substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.