GB2522643A

GB2522643A - Method of manufacturing a panel

Info

Publication number: GB2522643A
Application number: GB1401621.6A
Authority: GB
Inventors: Terry Douglas; Thomas Ryan
Original assignee: THERMOLUTION Ltd
Current assignee: THERMOLUTION Ltd
Priority date: 2014-01-30
Filing date: 2014-01-30
Publication date: 2015-08-05
Also published as: GB201401621D0

Abstract

There is provided a method of manufacturing a panel and in particular, to a method of manufacturing bathroom panels. The method comprises the steps of forming a core 16b in a first mould 20 and an outer layer 30b in a second mould 40. The core 16b and the outer layer 30b each have a top surface 12,32 and a bottom surface, the top surface 12,32 being formed by not being in contact with the mould. The top surfaces are levelled 12b, 32b, which may be by a machining process, and are then brought together to form the panel.

Description

Method of Manufacturing a Panel

Field of Invention

The invention relates to a method of manufacturing a panel having a core and skin, and in particular, to a method of manufacturing such panels having a high degree of flatness and dimensional accuracy.

Background to the Invention:

Panels, such as those used in bathrooms, and in particular, to those used in bathroom pods, provide an alternative and contemporary finish to more traditional tiling methods. A bathroom pod is a pre-fabricated bathroom that is used in commercial and domestic premises such as hotels and luxury apartments. Therefore, one of the functional benefits of panels isto reduce the installation skill and time because the panels cover a greater surface area in a reduced time compared to more traditional tiling methods. However, during the manufacture of such panels, the panels are susceptible to shape distortion, especially bowing. Any surface undulation in the panel prevents the panel being completely flat when installed which reduces the functional and aesthetic purpose of the panel. To minimise bowing, the process control of the panel's manufacture can be increased. However, this leads to direct cost increases to manufacture the panel. Size restrictions may therefore be imposed on the panels when the panels are produced by traditional methods, in order to minimise the risk of bowing. However, this approach is also unfavourable because a reduction in finished surface area negates the advantage of panels compared to traditional tiling methods.

A known method to manufacture such panels has been developed by Environmental Recycling Technologies Plc (ERT). The moulding process developed is known as Powder Impression Moulding (PIM). PIM is an open-mould technique that combines two moulds to form a cavity that replicates the shape of the desired moulding. Before the two moulds are brought together, the moulds are heated and layered with a skin material. The skin material is a powdered plastic material that adheres to each mould and forms an outer shell with a desired thickness. Once the skin is layered, a second powdered plastic material which includes a blowing agent is further layered onto one of the moulds. This second layer will eventually form the core. The two moulds are then brought together and further heated. This heating process causes the blowing agent of the core to expand within the first mould to progressively fill the space between the enveloping skin of the first and second moulds. After a curing and cooling process, the moulding is then removed to reveal a hard outer skin and a rigid inner core having a foam type structure.

A further known method to manufacture such panels is disclosed in EP2382074. Here the panels are manufactured by first forming an outer layer or a skin using a mould. This involves heating the skin material after pouring the skin material into the mould. The mould is then rocked and rolled to distribute the material around the surface of the mould. As the material cools on the surface of the mould, a skin is formed and the surface in contact with the mould provides the surface finish of the panel. Any excess skin material is then removed from the mould to leave a hollow core. To give the panel strength, the hollow core is then filled with a core material including a blowing agent, which advantageously provides the panel with a lightweight core. However, as the blowing agent cools and expands, the skin becomes pressurised and begins to distort by typically bowing outwardly, which prevents the production of a dimensionally stable and accurate flat panel.

There is a need to improve the method of manufacturing panels, such as bathroom panels to prevent shape distortion, such as bowing, or further minimise the occurrence of shape distortion.

It is an object of some aspects of the present invention to attempt to overcome at least one of the above or other identified problems.

It is a further object of the present invention to improve the manufacturing method to provide a dimensionally stable, flat panel.

Summary of the Invention

According to the present invention, there is provided a method of manufacturing a panel as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims and the description which follows.

According to an exemplary embodiment, a method of manufacturing a panel is provided.

The method is particularly suited for manufacturing bathroom panels that may be installed in bathroom pods, although the method may not be limited to such an application. The method comprises the step of forming a core using a first mould. An outer layer is formed separately.

Suitably, a separate mould is used to form each of the core and the first outer layer. The core material and the outer layer material fill the bottom surface and sides of the moulds. The moulds are left open at one end so that a top surface of the core and a top surface of the outer layer are not in contact with the mould. The bottom surface of the core and the first outer layer are in contact with the mould. The bottom surface of the outer layer provides the finished surface of the panel. The top surfaces of the core and outer layer are both levelled in order to make the top surfaces substantially flat. Here, the levelling takes place after the core and outer layer have substantially solidified. Any surface undulations or general surface roughness to the top surface is minimised or completely removed by the levelling process. For instance, suitably the levelling process is a machining process. The top surfaces are then brought together to form a panel. In this process, the panel becomes a 2-ply composite panel. The benefits of forming the core and outer layer separately are the avoidance or minimisation of shape distortion effects such as bowing. This allows large panels to be produced with a relatively flat surface finish. The levelling process removes any imperfections during the forming process. The top surfaces can be more easily joined and create a smoother finish.

The core and outer layer can be brought together evenly so that the two parts do not readily separate and provide a consistent join.

Preferably, the top surfaces are brought together using a bonding process. The bonding process may use an adhesive. This bonding process may result in an adhesive layer forming within the panel. Alternatively, the adhesive may be applied to more than one point on either one or both of the top surfaces.

Preferably, the outer layer that is formed during the manufacturing process is flexible.

This allows the outer layer to be easily handled, especially when the outer layer and core are to be brought together manually. Here, the core provides the structural strength to the outer layer.

Preferably, the outer layer is impermeable. An outer layer that is impervious to fluid, such as water, makes the panel attractive for installation in wet environments such as in a bathroom. The outer layer may become non-porous when the outer layer is formed in the mould. An effectively sealed outer layer helps to avoid the need to treat the panel after installation which is required on traditional tiles made from natural stone, for instance.

Preferably, the outer layer or skin is made from High Impact Polystyrene (HIPS). The HIPS material may be a recycled material.

Preferably, the core is an insulation material and provides the panel with insulation. The core may improve the insulation qualities of the panel in order to reduce the susceptibility of the outer layer to produce condensate in the wet environment.

Preferably, the core is a composition of various materials in order to recycle those materials. The composition may comprise various ratios of some or all of the following materials: HIPS, medium density or low density polyethylene (MDPE or LDPE), polypropylene, syntactic foam, which comprises recycled hollow glass spheres and a blowing agent.

Preferably, top surfaces of the outer layer and the core are brought together while the outer layer and core and present in their respective moulds. This may allow an indirect pressure to be applied to the outer layer and core in order to avoid damage to the bottom surfaces or any surface that is not the surface to be joined.

Preferably, the method of manufacturing the panel further comprises the step of blowing the core material. The core material first fills the mould and then the core material is blown to form an expanded state. The core material may be blown from a relatively liquid state. The benefit of a blown core material is that the expanded state is lightweight. The blown core material or blowing agent may act as insulation both in terms of sound insulation and heat insulation. The blowing agent is advantageous because the blowing agent fills the core in order to counteract any thermoplastic shrinkage as the core material cools. The blowing agent helps to reduce the amount of core material required which helps to reduce the overall weight of the panel.

Preferably, the method of manufacturing the panel further comprises the steps of forming a second outer layer in the second mould. This second mould was previously used to form the first outer layer. Similarly to the first outer layer, the second outer layer has a top and bottom surface wherein the top surface is not formed in contact with the mould. The bottom surface and further side surfaces may be in contact with the mould. Once the mould is filled by the second outer layer and has hardened, the top surface of the second outer layer is levelled. Finally, the second outer layer and the core are brought together. The top surface of the second outer layer and the bottom surface of the core are joined. Therefore, in combination with the first outer layer, the panel is a 3-ply composite. The advantage of producing the outer layer separately is to further avoid shape distortion effects of the second outer layer. The bottom surface, having been formed in contact with the mould, takes the shape of the mould. The panel is strong but has a finished surface on both sides. This may be useful when the panel is installed with a requirement to provide an impermeable surface to either side or when both sides form part of the wet environment.

Preferably, the method of manufacturing the panel further comprises the steps of levelling the bottom surface of the core before bringing together the top surface of the second outer layer. This provides a better surface to join the core and second outer layer.

Preferably, the levelling process is a machining process. This allows the relevant surfaces to be levelled with high accuracy in a quick and efficient manner. Any surface distortions such as bowing can be minimised or removed from the panel before the panel is installed.

Advantageously, the core is formed from a material including a mix of glass fragments, for instance glass beads or expanded glass beads. Here the glass material provides a hard material that machines well and tends to prevent cutting head from being clogged with melted polymer components. It will be appreciated that material other than glass having a high machinability due to a high hardness will be equally useful.

Preferably, the second outer layer is formed in a third mould. Different materials may be used to form the outer layers. The use of a third mould allows the outer layers to be constructed differently. Each outer layer may have different profiles and the moulds may be used to provide this finish.

Brief Description of the Drawings

Fora better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which: Figure 1 is a side cross-sectional view of a mould used to form a core and a mould used to form an outer layer of a panel; Figure 2 is a side cross-sectional view showing the levelling process of the core and outer layer; Figure 3 is a side view of the bring together of the core and outer layer to form a 2-ply composite panel; and Figure 4 is a side cross-sectional view of a 3-ply composite panel showing adhesive layers between the core and the outer layers.

Detailed Description of the Invention

Referring to Figures ito 3, a method of manufacturing a panel 100 is shown. First, the step of forming a core 10 in a first mould 20 and forming a skin or outer layer 30 in a second mould 40 is provided. Each of the core 10 and the outer layer 30 have a top surface 12,32 and a bottom surface 14,34. The bottom surfaces 14,34 are shown to be in contact with the respective moulds 20,40. The top surfaces 12,32 are not shown in contact with the moulds 20,40. This allows the top surfaces 12,32 to form freely in order to further process the top surfaces 12,32 separately.

The skin and core are shown being formed in separate moulds, which is likely to be the most effective production process. However, the same results would be achieved by forming and removing one from a mould and then forming and moulding the other from the same mould. What is important is that the skin and core are formed separately. Furthermore, although an open mould is shown other moulds that do not instil inbuilt stresses within the skin or core are equally applicable.

In Figure 1, the core 10 is shown in a first state 10 and second expanded state 16. The expanded state 16 is achieved by through a blowing agent within the material forming the core 10. The blowing agent causes the core 10 to expand within the mould 20 in the unconstrained directions shown. The bottom surface 14 of the unexpanded core 10 and expanded core 16 remains in contact with the bottom of the mould 20. However, the top surface 12 expands away from the bottom surface 14 during the expansion process. The expanded core 16 fills the mould 20. The expanded core 16 is typically allowed to substantially fully harden before the core 16 is removed from the mould.

As shown in Figure 2, the top surfaces 12,32 of the hardened outer layer 30 and expanded core 16 are then levelled to form a relatively flat top surface 12b,32b. The excess material is removed through the levelling process. This levelling process may be achieved while the expanded core 16 and outer layer 30 remain within the moulds 20,40. This step may depend on the height of the moulds 20,40 so that the top surfaces 12,32 can be sufficiently levelled. Suitably however, the solidified core and skin are removed from the moulds and levelled at a machining station. Here, the method includes removing the core and skin from the moulds and arranging on a machining station. Suitably, the levelling process is a machining process such as a milling or cutting process. Here the core and skin are placed and secured accurately to a flat surface ready for machining. For instance, the core and skin are placed with the fiat, bottom surface in contact with a flat machine bed. The machining process then removes a portion of the top surface and preferably at least a portion of the entire top surface. This ensures that the core and skin has an accurate and constant thickness required to meet the requirements of the intended product. The expanded core 16 and hardened outer layer 30 are processed to become a levelled core 16b and a levelled outer layer 30b.

The relatively flat top surfaces 12b,32b of the levelled core 16b and levelled outer layer 30b are then brought together in Figure 3 to form a panel 100. This panel is a 2-ply composite panel 100 and once bonded becomes a sandwich. Prior to bringing the outer layer 3Db together with the expanded core 16b, the outer layer 30 is relatively flexible. However, the expanded core 16b is relatively strong once in the expanded state. Therefore, rigidity of the expanded core 16b makes the levelled outer layer 30b rigid and the panel 100 can be easily handled. This helps to provide a flat surface during installation of the panel 100. The advantage of forming the core 10 and the outer layer 30 separately is to reduce the need to carefully distribute the unhardened outer layer 30 during the rocking and rolling process in the traditional method. This former traditional process required the skin 30 to be formed around the mould in order to produce a hollow core. Any excess skin material was then removed.

The process of rocking and rolling the outer layer material in the mould was therefore essential in the traditional method in order to form the skin or outer layer 30. However, the improved method has the benefit of reducing the need to rock and roll the mould. Furthermore, the amount of excess skin material that is needed during the process of forming the outer layer 30 is reduced through the improved method. The mould 40 used to form the outer layer 30 in the improved method has been separated from the mould 20 used to form the core 10, which allow after treatment of the core 10 before bringing together the core 10 and outer layer 30.

The core 10 may be comprised of a single material or a composition of various materials. Any of these materials may be recycled. The composition may comprise various ratios of some or all of the following materials: High Impact Polystyrene (HIPS), medium density or low density polyethylene (MDPE or LDPE), polypropylene, syntactic foam, which comprises recycled hollow glass spheres and a blowing agent. The blowing agent may be applied in a liquid state and then solidifies to an expanded state. In the expanded state the core 10 is hardened. Furthermore, the expanded state of the core 10 may have a cellular structure. This helps to improve thermal and acoustic insulation properties. By forming the core 10 and outer layer 30 separately in this way, the core 10 does not pressurise the outer layer 30 when the core 10 expands. Therefore, the top surfaces 12,32 of the core 1-and outer layer 30 can be levelled to improve contact and ensure that the panel 100 is flat.

The outer layer 30 and core 10 are formed in the mould by undergoing a cooking and subsequent cooling process. This occurs in separate moulds so both the outer layer 30 and core 10 can be handled separately. This helps to prevent any shape distortion effects that may occur as the core 10 expands and hardens to form a cellular structure. The outer layer 30 and core 10 are then levelled separately through, what may be a CNC machining process to specified tolerances. The outer layer 30 and core 10 are then bonded to form a sandwich.

The outer layer 30 of the panel 100 is impermeable to water. However, it is not necessary that the core 10 is impermeable because the core 10 may act as insulation to the panel 100.

Figure 4 shows a further embodiment whereby a second outer layer 250 is disposed on the panel 200. Here, the second skin is formed and assembled to the other side of the core in the same way as the first skin is formed and assembled to one side of the core. This second

B

outer layer 250 may be produced in the same mould which was used to form the first outer layer 230. The panel 200 consists of a core 210, a first outer layer 230, a second outer layer 250 and two adhesive layers 270,290. The top surfaces of the first outer layer is brought together on the top surface 212 of the core 210 and the top surface of the second outer layer is brought together on the bottom surface 214 of the core 210. The separation of the two outer layers helps avoid distortion of the panel 200 for instance any bowing effects. The bottom surface 214 of the core 210 may be levelled before the second outer layer is brought to the core 210. This may be a machining process in order to produce an accurate finish. Although not shown, the second outer layer 250 may be formed in a third mould, which is not shown. A third mould allows the outer layers to have different profiles or surface finishes and to also be concurrently produced which helps to reduce manufacturing timescales.

Consequently, there is provided a method of forming a panel having a core and a skin on at least one side, wherein the dimensional stability and accuracy of the panel is improved.

Specifically, a panel having a very consistent thickness across the entire panel can be achieved as well as a panel having a very flat surface without bowing or warping. Here the panels are typically greater than 0.5m in width and height with a thickness of around 0.05m.

The industrial application of the invention will be readily appreciated from the description herein. In particular, the panel is capable of being made in industry.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), orto any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

Claims 1. A method of manufacturing a panel, the method comprising the steps of: forming a core in a mould; substantially curing the core; levelling a first side of the core; forming an outer layer in a mould separately to the core; substantially curing the core; levelling a first side of the outer layer; and joining the levelled surfaces to form said panel.
2. The method of manufacturing a panel as claimed in claim 1 wherein the outer layer is flexible before being joined to the core.
3. The method of manufacturing a panel as claimed in claims 1 or 2, wherein the outer layer is impermeable.
4. The method of manufacturing a panel as claimed in any preceding claim, further comprising the step of: blowing the core material, such that the core cures in an expanded state.
5. The method of manufacturing a panel as claimed in any preceding claim, further comprising the steps of: forming a second outer layer in a mould substantially curing the second outer layer; levelling one surface of the second outer layer; and joining the levelled surface of the second outer layer with another surface of the core to form the panel.
6. The method of manufacturing a panel as claimed in claim 5, further comprising the step of levelling a second surface of the core before joining the levelled surface of the second outer layer.
7. The method of manufacturing a panel as claimed in any preceding claim, wherein the levelling process is a machining process.
8. The method of manufacturing a panel as claimed in claim 7, wherein the method comprises moving the core and skin from the mould to a machining station.
9. The method of any preceding claim wherein the core is formed in a first mould and the skin is formed in a second mould.
10. The method of manufacturing a panel as claimed in claimS, wherein the second outer layer is formed in a third mould.
11. The method of manufacturing a panel as claimed in any preceding claim, wherein the levelled side of the core is a top side, wherein the bottom opposed side is in contact with the mould.
12. The method of manufacturing a panel as claimed in any preceding claim, wherein the levelled side of the outer layer is a top side, wherein the bottom opposed side is in contact with the mould.