Fabric for a Window Treatment

Field of Invention

The present invention relates to a fabric for a window treatment. In particular, the present invention relates to an energy reflecting "blackout" or "thermal" fabric. In the following description it is noted that the term "window treatment" refers to curtains or blinds.

Background to the Invention

The majority of heat lost or gained by a room or building passes out or into its windows, a fact demonstrated by numerous technical developments in the field of glazing and by building legislation setting minimum levels of insulating and heat reflecting properties for different glazing applications.

There are two specific issues to be addressed;

1) Heat gain through sunlight hitting a window. This is often controlled by air conditioning, which is expensive to install, maintain and run, because of the energy consumed.

2) Heat loss from a warmer room to a colder exterior. Typically compensated for by the consumption of additional room heating energy.

Heat Gain: In some warmer climate countries, shutters are used to add insulation and shading to window openings, but these are cumbersome and expensive to fit retrospectively and represent a net addition to a building. In countries where curtains or blinds are common window treatments, then closing the window treatments will help to shade a room and its contents from sunlight hitting a window. This sunlight will heat the room and damage its contents, but conventional linings and fabrics will still allow some light and significant radiant heat to pass through them.

Heat Loss: In climates where it is necessary to heat rooms because of colder outside ambient temperatures, the windows of the room are the greatest source of heat loss, through heat transfer and draughts. Conventional curtain linings, fabrics and blinds provide only limited defence against this heat loss as they allow draughts to pass through them.

Whilst the fashion for and choice of window treatments vary across the world, curtains and blinds are a common feature of hotels in most countries. In most cases, it will be a legal requirement that the fabrics and linings are flame retardant.

For new buildings, there are a number of architectural features, such as Brise Soleil, design techniques and material specifications that can be employed to help building and window insulation. However, these features tend to focus either on heat loss or heat gain alone, so cannot easily be "switched" from one mode to another. In the case of a South facing room in a building located in country with cold winters, it is quite possible for that room to overheat in the summer because of sunlight, but require heating in the winter.

In an existing building with glazing in place, to whichever specification, and with replacement to a higher specification a very significant cost, the options for improving the window insulation are limited. Reflecting films can be applied to windows, but are fixed and tend to focus on reflecting solar heat away from the room, rather than insulating from heat loss. Conventional window treatments offer limited benefit and even with the addition of so called "Thermal Lining" and insulating "Interlining", such window treatments tend to simply trap an insulating layer of air, the additional features intended to trap more air making the window treatments thick, heavy and cumbersome. The design fashion in homes and hotels has also tended towards minimalism, making such heavy window treatments less desirable, but the retrospective application of new layers such as interlining is also not practical.

"Thermal" is a name given to linings with a single layer of coating, the idea being that the coat prevents the movement of draughts through the fabric. However, this is a historically generic term used in the curtain industry and is not regarded as describing any thermal properties of the window treatment/window treatment lining.

"Blackout" is the name given to window treatment linings with one or more coats of light blocking coating, commonly used in bedrooms and hotel rooms.

Light weight metallised synthetic fabric has been used in window treatments, but in countries where there is a culture of making quality window treatments and in hotel applications, this type of fabric has been considered inadequate and unattractive as the lining itself, expensive, inconvenient and unfamiliar as an interlining. The light metallised fabric does not block out light, was found to lose its reflective coating when washed and was not available in wider width.

Other metallised fabrics have been produced by laminating a metallic foil layer to a textile substrate, but the results have been stiff and unsuitable for curtains. The curtain market is conservative and so unfamiliar fabrics and techniques are difficult to introduce with any broad acceptance.

It is an object of the present invention to provide a window treatment and/or window treatment lining with improved thermal performance properties which overcomes or substantially mitigates the above mentioned problems with the prior art.

Summary of the Invention

According to a first aspect of the invention there is provided a fabric for use as a lining for a window treatment, the fabric comprising; a metallised fabric layer; and a coating layer, wherein the coating layer abutting the metallised fabric layer comprises a blackout coating.

The fabric according to the first aspect of the invention comprises the characteristics of energy reflection and light blocking (blackout), without compromising the essential aesthetic and manufacturing characteristics of conventional linings. In the case of the present invention, this is achieved through the application of one or more layers of light and draught blocking coating to an energy reflective substrate textile.

Optionally, the fabric comprises a flock application.

Optionally, the fabric comprises a plurality of coating layers, the coating layer distal to the metallised fabric layer comprising a flock application. Optionally, the metallised fabric layer comprises metallised yarns and standard yarns which have been woven together.

Optionally, the metallised fabric layer comprises synthetic yarns having a metallic component on the surface of the yarns.

According to a second aspect of the invention there is provided a window treatment comprising a main curtain fabric and a lining wherein the lining comprises a fabric according to the first aspect of the invention.

Optionally, the window treatment comprises the lining being integrally attached to the main curtain fabric. For example, being sewn in.

Optionally, the window treatment comprises the lining being removeably attached to the main curtain fabric such that it can be mounted in a first configuration in which the metallised fabric layer faces away from the main curtain fabric and a second configuration in which the metallised fabric layer faces toward the main curtain fabric.

According to a third aspect of the invention there is provided a readymade fabric panel for use with a window treatment or as a standalone curtain element comprising a panel of fabric wherein the panel of fabric is made from the fabric according to the first aspect of the invention.

According to fourth aspect of the invention there is provided a method of making a fabric for use as a lining for a window treatment, the method comprising; extruding metallised yarns and standard yarns; weaving a substrate fabric comprising the extruded metallised yarns and standard yarns; coating the substrate fabric with a coating layer.

Optionally, the method comprises applying a flock application to an outer coating layer.

Embodiments of the present invention provide a fabric suitable for window treatments with the following characteristics.

• Active reflection of heat energy.

• Blocking out of light which cannot pass through the fabric. This is termed "Blackout".

• Attractive as a curtain lining, whilst acceptably thin, light and draping, and compatible with existing curtain constructions and hanging systems.

• Suitable to be cut and sewn using existing systems and equipment.

• Suitable for use in blinds.

• Washable, whilst retaining all its properties. • Attachable to an existing curtain retrospectively or can be hung separately on its own mechanism.

• Offering a flame retardant option for the hotel and contract sectors.

• Available in wide width for seamless applications in larger windows and hotels.

The active reflection of heat energy is achieved through metallisation of the substrate or through the production of the substrate using metallised components. These components must also satisfy the key curtain and blind market's fabric requirements listed above.

It is also noted that existing production technology available for heat reflecting fabrics is largely restricted to "narrow width" (140-150cm) production, whereas window treatment producers for larger windows and hotels prefer "wide width" (280-300cm) fabrics, so that window treatments can be produced without seams between panels. This is particularly important where the window treatment is a blackout as seams allow unsightly and distracting lines of light to pass through a window treatment intended to black out a room. Embodiments of the present invention also address this issue.

The fabric according to the first aspect of the present invention is referred to herein as an Energy Reflecting Fabric (ERF).

The lining may also be used as a stand-alone fabric (e.g. without a main face fabric) without restriction of its performance.

Conveniently, the lining may also be constructed as a separate panel, the curtain lining being removeably attached to the main curtain fabric such that it can be mounted in a first configuration in which a first side of the lining faces away from the main curtain fabric and a second configuration in which the first side of the lining faces toward the main curtain fabric. The fabric according to embodiments of the present invention has been shown to be effective in reflecting energy from both the metallic side and, to a lesser extent the coated side, so need not be reversible to be effective. If the fabric is fixed in orientation in the window, it would be then be recommended to face the metallic side to the window if heat ingress were the priority issue, or to the room if heat loss were the main priority.

The Energy Reflecting Fabric (ERF) uses metallised and standard yarns to produce a woven or knitted substrate fabric which is then coated with one or more layers of a thin, continuous coating, to create a fabric with the properties listed above. Regardless of the number of coats, the final coat has an application of flock (fine short staple fibres) applied whilst the coat is still adhesive. This has the combined effects of softening the fabric, enhancing the feel of the fabric and preventing it from sticking to itself when rolled and stored under pressure from rolls above.

Brief Description of the Drawings

Figure 1 illustrates an arrangement of fabric components according to an embodiment of the present invention.

Figure 2 illustrates an arrangement of fabric components according to an embodiment of the present invention. Figure 3 is a flowchart illustrating a production route of the fabric according to an embodiment of the present invention.

Figure 4 illustrates a window treatment lining reducing the heating of a room by the sun, according to an embodiment of the present invention.

Figure 5 illustrates a window treatment lining reducing the loss of heat from a room to the outside according to an embodiment of the present invention.

Figure 6 illustrates a reversible window treatment lining reducing the heating of a room by the sun, according to an embodiment of the present invention.

Figure 7 illustrates a reversible window treatment lining reducing the loss of heat from a room to the outside, according to an embodiment of the present invention.

Detailed Description

It is noted that like features within the Figures are denoted by like numerals.

The present invention comprises a woven fabric with metallised synthetic warp yarns and standard synthetic weft yarns, providing energy reflecting characteristics to both sides of the fabric. One or more coats of coating are then applied to the fabric to add the characteristics of light and draught exclusion. It is the combination of these characteristics in one fabric specifically suitable for window treatments which represent the invention. The components may be arranged as shown in Figures 1 & 2, where Figure 1 shows an arrangement 100 of the fabric with a layer of metallised fabric 102 abutting a coating later with a flock application 104 and Figure 2 shows an arrangement 200 with a plurality of layers comprising a metallised fabric 202 abutting a first coating layer 204, which in turn is abutting a second coating layer 206 and where the second coating layer is abutting a third coating layer with a flock application 208.

The production route may be as described by the flowchart 300 shown in Figure 3 (Note: FR = flame retardant; non-FR = standard coating which is not flame retardant). In a first step 302, the metallic and standard yarns are extruded. Then, in step 304, the weave or knitting beam is prepared and sized. Next the substrate fabric is knitted or weaved, as shown by step 306. The fabric substrate is then finished such that it is clean, flat and stable, which is given in step 308. The substrate fabric is prepared for coating, step 310, and coated one or more times in FR or non-FR coatings, which is shown in step 312. Finally in step 314, the finished fabric is trimmed, inspected and packed.

The resulting product is a fabric that is acceptable for curtain and blind making, in terms of cutting, sewing, drape, construction, appearance and washing, whilst reflecting heat energy, excluding draughts and blocking out light. The fabric is reversible so as to maximise energy reflection either back into or away from the room, can be produced in a flame retardant version and can be retrospectively fitted to the back of curtains through the use of a made to measure or readymade reversible panel hung on the back of an existing curtain.

Tests were undertaken by an accredited independent laboratory in the field of glazing and window performance to established glazing energy transmittance standard EN 13363-1.

Face fabrics vary in weight and construction so significantly that it was chosen not to set a face fabric control. A single pane of clear 4mm high translucent glazing alone (Control 1), and in conjunction with a commonly used 50% Cotton, 50% Polyester lining (Control 2) were therefore set as a controls to show how much the ERF fabric reduced energy transmittance when also paired with the same 4mm glazing.

Because the glazing itself reflects some energy, the most significant reductions in energy transmittance were achieved with the metallic side of the ERF facing the energy source, (as recommended) and between the energy source and the glazing. The reduction of energy transmittance through the combination of the control lining + glazing and the ERF + glazing could then be assessed.

The reduction of energy transmittance with the glazing between the energy source and the lining or ERF were also measured, so that we could assess the ERF being used in a fixed window treatment, reflecting heat into a room in the winter AND then out of a room in the summer.

Taking the Control as 100% in each circumstance, we show below the % to which the energy transmittance was reduced by the ERF and (the % reduction)

V's Control 1 (glazing only)

ERF between glazing and energy source 17% (83% reduction)

Glazing between ERF and energy source 60% (40% reduction)

V's Control 2 (glazing + control lining)

ERF between glazing and energy source 22% (78% reduction)

Glazing between ERF and energy source 79% (21 % reduction)

It can be seen from the above that in the case of the ERF between the energy source and glazing, the very slight decrease in reduction when the control includes the standard control lining shows the ineffectiveness of such standard linings compared to the ERF.

The ERF can be employed in a number of ways, as a window treatment lining, as a standalone window treatment and as a separate panel to be attached to or suspended in conjunction with existing window treatments. This is described further in the separate configurations explained by Figures 4, 5, 6 & 7.

A window treatment lining according to an embodiment of the present invention is illustrated in Figure 4, which reduces the heating of a room by the sun and which can either be integral or hung separately to the face fabric. In Figure 4 it can be seen, as indicated by arrow 400 that sunlight heat energy from the sun 402 strikes the window. The window lining treatment comprises a metallised side of the ERF 404, and a coated side of the ERF 406. The decorative face fabric 408 is sewn to, attached to or hung separately on the room-side of the ERF lining. The window treatment lining reflects heat energy 410 from the incoming sunlight heat energy 400, thus reducing the heating of the room.

In Figure 4, the metallic face of the ERF 404 is positioned in the window treatment to be facing and adjacent to the glazing. The ERF layer could be sewn in as integral to the face fabric window treatment, or could be hung separately on a separate hanging mechanism. In this example, the ERF could also be employed as a stand-alone window treatment without a decorative face fabric 408.

A window treatment lining according to an embodiment of the present invention is shown in Figure 5, being used to reduce the loss of heat from a room to the inside. Again the window treatment lining may be integral or hung separately to the face fabric. The room heat energy strikes the curtain, illustrated by arrow 500. Similarly to Figure 4, the decorative face fabric 408 may be sewn to, attached to or hung separately from the room-side of the ERF lining. The heat energy is reflected 502 by the window lining treatment back into the room, thus reducing the loss of heat from the room to the outside.

In the case illustrated by Figure 5, the metallic face of the ERF 404 is positioned in the window treatment to be facing the room with the coated side 406 adjacent to the glazing. The ERF layer could be sewn in as integral to the face fabric window treatment, or could be hung separately on a separate hanging mechanism. In this example, the ERF could also be employed as a stand-alone window treatment without a decorative face fabric 408.

Another example use of the window treatment lining is shown in Figure 6, where a reversible window treatment lining is employed as appropriate to the prevailing temperature conditions, retrospectively hung from the face fabric window treatment itself, or separately. As shown in Figure 6, the ERF lining curtain is hung separately 600 from the decorative face fabric curtain 408.

In the example illustrated in Figure 6, the ERF is produced as a separate panel 600 to the face fabric window treatment. This panel is reversible by means of a specific curtain tape and hooks, or by using "hook and loop" tape to allow it to be removed from, reversed and reattached to the face window treatment. Standard panel sizes exist for standard readymade curtain sizes. In other cases, commonly in hotels, window treatments are hung in layers on separate tracking systems, so allowing the ERF panels to be reversed as appropriate. In either application, the ERF is orientated as shown in either Figure 4 or Figure 5.

Figure 7 illustrates the window treatment lining configuration of Figure 6, but where the lining curtain is hung separately from the decorative face fabric curtain in order to reduce heat loss from the room to the outside.

The key advantage of the ERF is that it integrates a new performance characteristic (active energy reflectance) generally not easily incorporated in curtains and blinds, with an established lining characteristic (blackout) without changing the way in which the lining can be employed. Previous solutions have involved building into the curtain or blind one or more additional components, changing the established ways of production, whilst compromising appearance and drape and adding cost.

ERF is reversible to optimise its performance by directing the metallised side to the source of heat, be it the sun or the room. Correct use of ERF will therefore allow it to be used to protect a room from the sun in the summer and from the cold in the winter, at the same time fulfilling all the requirements of a regular blackout curtain lining.

Embodiments of the present invention provide a new and important energy reflecting performance characteristic to a window treatment lining or to stand-alone window treatment using the present invention alone. Such performance characteristics are also commercially significant in that they add only incremental cost to a lining that would be employed in any case and does not add any cost to the production of the curtain or blind itself. This is considered particularly important in the hotel sector, where flame retardant blackout curtain linings are commonly used, meaning that the incremental additional cost of the ERF will be easily justifiable through savings on heating and air conditioning costs.

Variations:

It is the combination of a suitable weight and construction ER property fabric with blackout property coating, which can also be flame retardant, which makes this invention unique. There are other means by which this combination of characteristics could be achieved:

The ERF development fabric is based on a woven fabric constructed with metallised yarn in the warp direction and standard polyester yarn in the weft direction. This presents sufficient metallised yarn to the face of the fabric to be ER effective. Even a very low percentage content by weight of the metallic component is effective if it is applied to the surface of the yarn.

The standard yarn could be spun from other materials and it would be possible to reverse the direction of the yarns, so that the metallised yarn ran in the weft direction, or to make the fabric from 100% metallised yarn, or to alternate standard and metallised yarn in the warp and weft directions.

Similarly, it would be possible to produce a knitted substrate fabric with metallised and standard yarn combined, or 100% metallised yarn, with alternative constructions. Non- woven textiles could also be used a metallised substrate.

In ERF, the blackout coating is applied directly to the substrate fabric. It would be possible to bond together through a process such as lamination both a blackout fabric and an ER fabric.

It is noted that embodiments of the present invention may also comprise a ready-made reversible lining that can be retrospectively hung on the back of an existing face curtain, or hung as a standalone curtain where there is no existing face curtain.