AU2019236584A1

AU2019236584A1 - Composite Panels

Info

Publication number: AU2019236584A1
Application number: AU2019236584A
Authority: AU
Inventors: Daniel Charles Underwood
Original assignee: Underwood Cos Holdings Pty Ltd
Current assignee: Underwood Cos Holdings Pty Ltd
Priority date: 2018-09-21
Filing date: 2019-09-23
Publication date: 2020-04-09

Abstract

Abstract with Fig 11 A composite panel assembly has a concealed overlap which is used to extend a moisture barrier across adjacent overlaps of other panels, the folded out layer is shown in phantom at the extended position 15 of the layer 12 and then it is folded over the frame on one edge at 37 and then this is followed up on the edge at 38, again this is all carried out prior to application of the securement layer during a heating stage. This conceals the folded marginal edge section of the layer 12, it can be cut free and extended from its folded concealed position.

Description

COMPOSITE PANELS

TECHNICAL FIELD [0001] THIS INVENTION relates to composite panels and in particular but not limited to composite panels forming lost formwork for inhibiting moisture passage across the formwork.

BACKGROUND [0002] Concrete construction often employs formwork that is stripped after concrete has sufficiently cured. In other cases lost formwork is left in-situ. Moisture at any time can be detrimental to the finished concrete. It is an object of the present invention to provide a panel which may be used in concrete formwork, especially lost formwork, to inhibit the passage of moisture across the formwork.

OUTLINE [0003] In one form there is provided a composite panel assembly having a structural grid frame supporting at least two layers of thin plastics film, at least one layer being a moisture impermeable layer, the layers being secured to the frame, the panel holding a marginal section used to overlap with an adjacent panel. In a preferred aspect there is provided a composite panel assembly having a structural grid frame supporting at least two layers of thin plastics film, the first layer being a securement layer and the second layer being a moisture impermeable layer, the layers being secured to the frame, the panel preferably holds a marginal section used to overlap with adjacent panels. Preferably, the layers are secured together and to the frame. The layers may be a tight fit and secured about a peripheral edge of the frame as an envelope or across mating surfaces or through the frame or be independently secured to the frame or to a further layer superimposed across the other layers to form a sandwich structure enclosing the frame and the moisture impermeable layer.

[0004] In a preferred embodiment the composite panel assembly comprises a sandwich structure where the frame is between the securement layer and the moisture impermeable layer.

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Typically, in this embodiment the layers are secured to each other through spaces in the frame.

In another embodiment there are two securement layers which envelop the frame and the moisture impermeable layer.

[0005] The securement layer may be used to secure the assembly by being heated to shrink about the frame and/or heated to weld itself to the other layer without affecting the moisture impermeability characteristic of that layer. In this regard there is preferably a temperature differential between the melting points of the plastics employed so that during a process heating phase heat is applied to effect the securement layer(s) but not the moisture impermeable layer.

[0006] The frame may be of a metal grid frame and may be a rigid frame or may be bendable or otherwise deformable so that it may be fashioned into different formwork shapes as in for example a trench like shape for footings and so on. The plastics layers may be applied so that in a finished flat assembly the whole assembly may be formed.

[0007] Preferably, a marginal edge region of the moisture impermeable layer extends beyond a corresponding edge of the frame so that in a finished and installed formwork when edges of the frames of adjacent panels are set in contiguous relative position, the moisture impermeable layers of adjacent panels may overlap. This ensures a continuous barrier. In some cases, in use marginal end portions of adjacent assemblies may overlap or a tape may be employed with the tape overlapping abutting edges. Where the frames have a grid of wires, typically welded together at the junctures of the wires, in one embodiment, at least the first wire running along the line of the intended overlap is located on the opposite side of the frame so that the wires extending across the overlap of the overlapping panels are in contact across the full width of the overlap by reason of the wire being on the opposite side.

[0008] The marginal edge regions of the moisture impermeable layer may extend out from one, or two or more edges of the frame. In the assembled panel, the marginal edge regions may be concealed inside the panel for transport purposes and retrieved or extracted later. The marginal edge region may be folded into a pocket. This may be before the panel is processed by heating and welding the layers. The folds may be separated by release sheets to prevent them being welded and therefore still being able to unfold.

2019236584 23 Sep 2019 [0009] In another aspect the present invention resides in a method of producing a composite panel assembly as described above, the method including the following steps:- (1) providing a supporting frame;

(2) applying the said two layers to the frame;

(3) subsequently heating the frame and the layers applied thereto to complete securement of the layers to the frame.

[0010] Preferably step (2) includes the further step of applying the moisture impermeable layer to the frame with a folded edge region or otherwise accumulated marginal edge region and step (3) includes the further step of applying the securement layer over the folded marginal edge region to conceal it in the assembly.

BRIEF DESCRIPTION OF THE DRAWINGS [0011] In order that the present improvements may be more readily understood and put into practical effect reference will now be made to the accompanying drawings and wherein:Figure 1 is a cutaway view illustrating part of a typical panel assembly;

Figure 2 is a drawing illustrating a panel assembly formed into typical formwork for trench for footings;

Figure 3 is a drawing illustrating overlapping panels formed in accordance with Figure 2 for a longer trench;

Figure 4 is a drawing illustrating one example of how the present invention effectively repels moisture;

Figures 5 to 8 illustrate examples of application of a moisture impermeable layer to a meshed frame where marginal sections shown in phantom a folded back over the frame for concealment during transport;

Figures 9 to 11 illustrate how a marginal edge region of a moisture impermeable layer may be stored for transport;

Figures 12A to 12F illustrate how a marginal edge region may be stored so that it may be easily extended in use;

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Figures 13 and 14 illustrate one example of the use of a release material used to reduce adhesion of the securement layer which might inhibit unfolding where there are heating processes employed;

Figure 15 is a schematic drawing illustrating application of a heat shrink securement layer; and Figures 16A to 16F illustrate a typical process suitable for implementation of the present invention.

METHOD OF PERFORMANCE [0012] Referring to the drawings and initially to Figure 1 there is illustrated a composite panel assembly 10 having a supporting frame 11 in the form of a steel mesh. In this case three plastics films are used as a moisture impermeable layer 12 between securement layers 13 and 14 which are employed primarily to ensure the integrity of the layer 12 while securing the whole assembly. In the present case these are heat shrink plastics layers that are heat shrunk around the frame. The frame in this case is a welded grid of 4 mm to 6 mm steel. This panel is made flat and may be deformed into different shapes to be used as lost formwork for concrete. The moisture impermeable layer protects the concrete from moisture passing across the formwork.

[0013] Referring now to Figure 2, Figure 2 illustrates a panel 10 folded into a U shaped formwork which may be located in the ground for the purpose of pouring footings. A marginal edge region of the moisture impermeable layer 12 numbered 15 has been extended out beyond the edges 16,17 and 18 of the folded panel 10. This is for the purpose of overlap with more panels. This is shown in the arrangement of Figure 3 where panels 10 are located in abutment, the marginal edge regions at 19 are overlapped along with the panels 10 which are in alignment. It will be appreciated that when concrete is poured into the region 20 formed by the folded panels 10 that the moisture barrier will extend the full length of the formwork and the moisture impermeable layer marginal portions shown at 21 and 22 at each end may overlap with further sections. Likewise should it be desirable to extend the formwork upward, as depicted in Figure 2 the moisture impermeable layer 12 has been formed with a complete margin around the panel 10 so that similar overlapping sections may be applied in an upwards direction should that be desirable.

2019236584 23 Sep 2019 [0014] Figure 4 illustrates another example whereby a wall 23 employs the panels 10 one of which is shown at 24 forming a trench and another panel 10 shown at 25 forming a form extending below ground level in the region of overlap at 26 and it will be appreciated that the water impermeable layer 12 extends around and the repellent ability is illustrated schematically by the reflecting arrows at 27 along the panel. The sheets 24 and 25 are shown overlapping and in close overlapping relation, in this case the outermost wire on one of the panels at the overlap will be welded to the outside or the opposite side to the other wires so that the panels can overlap in clase contact. This means both outer wires are on the outside of the overlap. In the following examples the panels abut but they could also overlap, to aid overlapping the outer wire of at least one panel would be welded on the opposite side of the panel.

[0015] Referring now to Figures 5 to 8 there are four possibilities illustrated of panel assemblies that utilise the same frame 28 but utilise a different impermeable layer with different overlap capabilities. A single extension is illustrated in Figure 7 at 29, three extensions on three edges illustrated at 30 in Figure 5, opposite edges at 31 in Figure 8 and a complete margin around the frame at 32, each of these margins is represented in phantom. In each drawing in the final panel the margin has been folded and is shown by by the cross line across each edge showing that the margin defined in phantom is folded over to be about as wide as the frame grid with to just aligned with or just inside the outer edge 33 of each of the frames. It will be appreciated that the only assembly which is missing in these drawings is where the opposite edge of the frame of Figure 7 would extend as well. These drawings serve to illustrate the types of arrangements and possibilities that are applicable to the present invention. In each case once the impermeable layer is applied and folded in over the frame then the so assembled frame and impermeable layer may be fed through a heater after the frame is sandwiched by a single sheet of heat shrinkable material or the frame and moisture impermeable layer are sandwiched between two heat shrinkable sheets. The arrangement illustrated in Figures 5 to 8 two sheets of heat shrinkable material is used thereby encapsulating and concealing the folded marginal edge portions of the impermeable layer 12.

[0016] Referring now to Figures 9 to 11 illustrated in Figure 9 is a folded marginal edge section 34 which is folded so as to be just inside the edge 33 of the frame. Figure 10 illustrates a rolled marginal edge section 35 which again is rolled up to be just inside the edge 33. These are all

2019236584 23 Sep 2019 initially secured in place with tapes 36 at spaced locations along the rolled or folded sections.

This is all arranged so that upon application of the securement layer the folded section 34 or the rolled section 35 may be concealed within the securement layer.

[0017] Referring to Figure 11 there is illustrated in phantom the extended position 15 of the layer 12 and then it is folded over the frame on one edge at 37 and then this is followed up on the edge at 38, again this is all carried out prior to application of the securement layer.

[0018] The folded marginal edge section of the layer 12 is to be extended from its folded concealed position. This means the outer layer must be cut open on site. In order to obviate any difficulty doing this to expose an accessible edge of the marginal edge section so it may be pulled from within the assembly, the applicant has devised a folding method whereby the folded marginal region may present itself upon a slit being cut down the edge of the assembly and thereby easily removed. This folding arrangement is shown in sequence in Figures 12A through 12F.

[0019] Once the fold is set in Figures 12A to 12 F then it is a simple matter to fit a release film or paper 39 by simply lifting and inserting as shown in Figures 13 and 14 so that the paper forms surround the folded section at 40 between it and the heat shrink layer so that during a process heating stage the heat shrink plastic does not adhere to the folded section. It effectively becomes held in a pocket where it can later be cut free and unfolded.

[0020] After Figure 14 there only the two layers, supporting frame and the impermeable layer which is preparatory to having the securements layers applied on either side. The heat shrink layers are applied so they extends across and beyond the folded section at 40 on either side to the position shown in Figure 15 (the bottom layer being shown). A top layer of the same size is applied and then the whole is heated in an oven and the edges shrink in to encapsulate the whole assembly.

[0021] As can be seen in Figures 13 and 14 the rolled edge of the paper 39 at 41 is located inside the last wire 42 and it will be further appreciated that the securement layers will extend over this wire 42 and since the paper at 41 and is placed inside the wire 42 it will mean that a

2019236584 23 Sep 2019 cutting blade can be run along the outside the wire 42 to open the side of the panel. The paper and the fold and the position inboard of where the cut is being made will ensure that the moisture impermeable layer 12 is not inadvertently cut. Once the cut is made the full length then the paper can be extracted and the folded marginal edge section will be easily extracted by way of pulling the folded section out through the opening so made. Due to the folding process the marginal region will simply unfold.

[0022] Referring now to Figure 15 there is illustrated the preheating positioning of the metal frame 11 atop the sheet 12 which is folded over which in this case is a clear sheet folded over with the marginal edge shown at 43. On the underside of this is the securement sheet 44 which together pass through a set of rollers 45 and 46. The sheet 44 will adhere to the sheet 12 through the spaces in the frame 11. This process is illustrated in 16A and 16B.

[0023] In another process the panel is assembled as in Figures 12A through 14, shown in Figure 16C and then sandwiched between two heat shrink layers as depicted in Figures 16D to 16F.

[0024] Figure 16C there is a panel with folded opposite edge portions at 40 and the sheet 12 located atop the frame 11 is fed into a heater or oven at 47, the process involving the securement films coming off rolls at 48 and 49 with a sealed edge at 50 so that the assembly of Figure 16C is pushed through, drawing the securement layers 51 and 52 to a position where cutter 53 cuts the films off at the end it being appreciated that the two sides of the film extend beyond the opposite side edges of the frame so that upon application of the heat the heat shrink layers shrink around the frame evenly on all edges.

[0025] So that air can be completely expelled from the assembly it is passed through spike rollers at 54 shown in greater detail in Figure 16F which punches small holes in the outer layers and these rollers also serve to expel the air but the moisture impermeable layer at 12 is sufficiently thick such that it does not get perforated as the panel passes through the rollers.

EXAMPLES [0026] Set out in the table below are examples of two applications of the above invention where a first perforated sheet is used with a similar characteristic sheet and in the second column a relatively thin high shrink film or films are used with a thicker non-permeable sheet.

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TECHNICAL SPECIFICATION

PRODUCT	Same plastic heat shrink sheet both sides	Addition of thicker layer lower shrink sheet on one side or between high shrink sheets
Mesh	VR 6 Standard	VR 6 Standard
Main Wire Size [Nominal]	5.5 mm Diameter	5.5 mm Diameter
Main Wire Spacing	150 mm c/c	150 mm c/c
Cross Wire Size [Nominal]	4.0 mm Diameter	4.0 mm Diameter
Cross wire Spacing	100 mm c/c	100 mm c/c
Wire Specification	High tensile steel of strength 485 Nmm2. Non Galvanised	High tensile steel of strength 485 Nmm2. Non Galvanised
Polyethylene Colour	Green both side	Green on Bottom , Yellow or clear on Top
Polyethylene Film [Green]	0.12 mm thick - one layer each side	0.12 mm thick - One layer on bottom side
LDPE Film [Yellow or clear]		0.25 mm thick - One layer on Top side
Oven Temperature	200 - 220 Degree C	180 - 190 Degree C
Conveyor Speed	9 meter / minute	6 meter / minute

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Weight [ m2 ]	2.64 kg	2.8 kg
Standard Size	PCS / Hr	PCS / Hr
600 mm x 2250 mm	150 pcs	100 pcs
900 mm x 2250 mm	100 pcs	80 pcs
1200 mm x 2250 mm	80 pcs	60 pcs
1500 mm x 2250 mm	65 pcs	50 pcs
1800 mm x 2250 mm	50 pcs	40 pcs
Standard Plastic — TOP	2370 mm	2300 mm
Bottom	2370 mm	2370 mm

[0027] Whilst the above has been given by way of illustrative example many variations and modifications will be apparent to those skilled in the art without departing from the broad ambit and scope of the invention as herein set out in the appended claims.

Claims

1. A composite panel assembly having a structural grid frame supporting at least two layers of thin plastics film, at least one layer being a moisture impermeable layer, the layers being secured to the frame, the panel holding a marginal section used to overlap with an adjacent panel.

(2) applying the said two layers to the frame;

2. A composite panel assembly according to claim 1 wherein the first layer is a securement layer and the second layer is the moisture impermeable layer, the layers being secured to the frame.

3. A composite panel assembly according to any one of the preceding claims, the layers being a tight fit and secured about a peripheral edge of the frame as an envelope or across mating surfaces or through the frame or be independently secured to the frame or to a further layer superimposed across the other layers to form a sandwich structure enclosing the frame and the moisture impermeable layer.

4. A composite panel assembly according to any one of the preceding claims wherein the composite panel assembly comprises a sandwich structure where the frame is between the securement layer and the moisture impermeable layer.

5. A composite panel assembly according to any one of the preceding claims wherein the layers are secured to each other through spaces in the frame and there are two securement layers which envelop the frame and the moisture impermeable layer.

6. A composite panel assembly according to any one of the preceding claims wherein there is a temperature differential between the melting points of the plastics employed so that during a process heating phase heat is applied to effect the securement layer(s) but not the moisture impermeable layer.

7. A composite panel assembly according to any one of the preceding claims wherein the marginal section being held is a marginal edge region of the moisture impermeable layer which

2019236584 23 Sep 2019 extends beyond a corresponding edge of the frame so that when finished and installed edges of the frames of adjacent panels are set in contiguous relative position, the moisture impermeable layers of adjacent panels may overlap by reason of overlap of their corresponding held regions.

8. A composite panel assembly according to any one of the preceding claims wherein in use marginal end portions of adjacent assemblies may overlap or a tape may be employed with the tape overlapping abutting edges.

9. A composite panel assembly according to any one of the preceding claims herein where the frames have a grid of wires, at least the first wire running along the line of an intended overlap is located on the opposite side of the frame so that the wires extending across the overlap of the overlapping panels are in contact across the full width of the overlap by reason of the wire being on the opposite side.

10. A composite panel assembly according to any one of the preceding claims wherein marginal edge regions of the moisture impermeable layer may extend out from one, or two or more edges of the frame.

11. A composite panel assembly according to any one of the preceding claims wherein in the assembled panel, the marginal edge regions may be concealed inside the panel for transport purposes and retrieved or extracted later.

12. A composite panel assembly according to any one of the preceding claims made in a method of producing a composite panel assembly, the method including the following steps:- (1) providing a supporting frame;

13. The invention according to any one of the preceding claims wherein step (2) includes the further step of applying the moisture impermeable layer to the frame with a folded edge region or otherwise accumulated marginal edge region and step (3) includes the further step of

2019236584 23 Sep 2019 applying the securement layer over the folded marginal edge region to conceal it in the assembly.

14. The invention according to many one of the preceding claims wherein, the layers and method employed are substantially in accordance with the following technical specification:

TECHNICAL SPECIFICATION

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15. The invention according to many one of the preceding claims wherein a marginal edge region is folded into a pocket.

16. The invention according to many one of the preceding claims wherein a marginal edge region is folded into a pocket, before the panel is processed by heating and welding the layers, the folds being separated by release sheet(s) to prevent them being welded and therefore still being able to unfold.