The present invention relates to improvements in fabrics. More specifically the present invention relates to improvements in water resistant fabrics and their methods of manufacture.

Water resistant fabrics are used for a range of applications, one of the most important being clothing. The four main desirable properties of water resistant clothing are i) that the fabric is waterproof; and ii) that the fabric is breathable; iii) that the fabric exhibits low water absorbency so as to minimize weight gain in wet conditions; and iv) that the fabric is wind resistant.

As a generalisation there are four main types of water resistant fabrics used for clothing. These are DWR (Durable Water Repellency) fabrics, coated fabrics, membrane fabrics, and silicone barrier fabrics.

DWR (Durable Water Repellency) fabrics are those that are treated with a fluorochemical finish such as Nanotex (RTM). In general although these fabrics display good breathability, they also display poor water repellence, poor durability and do not exhibit good wind resistance.

Coated fabrics are those with a strong waterproof barrier coated on the back of the fabric. Most commonly used as a barrier are polyurethane, acrylic or silicone polymers. These fabrics usually are often also treated with fluorochemicals to delay wetting of the fabric itself and thereby minimize water absorpency. Although these fabrics display strong protection against water penetration, even under pressure, they have no air permeability. Thus, clothing made of these fabrics can be very uncomfortable owing to a lack of breathability and subsequent condensation inside the garment.

Membrane fabrics are constructed in a similar way to coated fabrics, but instead of coating the fabric with a suitable polymer, an thin waterproof membrane is glued to the back of the fabric. Just like coated fabrics, the shell fabric is often also treated with fluorochemicals. Membrane fabrics can be two layer fabrics (shell fabric + membrane) or three layer fabrics (shell fabric + membrane + underlining. One of the best known of these types of fabrics is sold under the brand name Gore-Tex (RTM). These fabrics demonstrate strong protection against water penetration, even under pressure, but have no air permeability. Thus, clothing made of these fabrics can be very uncomfortable owing to a lack of breathability and subsequent condensation inside the garment.

Silicone barrier fabrics are those such as that sold under the brand name EPIC (RTM) and as disclosed in international patent application no. WO8908555A1 . Unlike the other types of fabric, its protective barrier is build within the shell fabric itself, thereby creating a layer weather protective fabric with a high level of comfort. The barrier is formed by flowing silicone polymer (in gel/liquid form) into the shell fabric, thereby filling up the empty space in the fabric itself. The silicone barrier is then cured into a strong, soft durable synthetic rubber. However, such fabric has a relatively poor water resistance in that it allows rain penetration under prolonged exposure and allows water to penetrate through under pressure. Thus, although coated fabrics and membrane fabrics display good water and wind resistance, they exhibit poor breathability, and although DWR and silicone barrier fabrics display good breathability, they exhibit poor, or relatively poor water and wind resistance. It would be desirable for there to be fabric that displayed excellent water and wind resistant properties whilst at the same time achieving excellent breathability.

The present invention seeks to address this issue.

According to a first aspect of the present invention there is provided a weather resistant fabric comprising a shell fabric layer having first and second surfaces; characterized in that the shell fabric layer comprises internally an elastomeric barrier spaced from the first and second surfaces, and the fabric further comprises a hydrophobic breathable membrane layer on a surface of the shell fabric layer.

By providing an elastomeric barrier layer inside a shell fabric layer, such that it is spaced from both first and second surfaces, it is possible to apply a hydrophobic membrane layer to the shell fabric layer.

Preferably the elastomeric barrier is a silicone barrier. Preferably the silicone barrier is formed from a liquid silicone rubber.

A silicone barrier provides suitable water resistant properties.

Preferably the elastomeric barrier constitutes 5 to 30wt% of the shell fabric layer.

A suitable wt% for the elastomeric barrier is in the range of 5 to 30wt%.

Preferably the elastomeric barrier constitutes 1 0 to 20wt% of the shell fabric layer.

A preferred wt% for the elastomeric barrier is in the range of 10 to 20wt%.

Preferably the membrane layer is laminated on the shell fabric layer. Lamination of the membrane layer is an ideal way to attach it to the shell fabric layer.

Preferably the membrane layer is a PTFE membrane. A PTFE membrane layer provides suitable hydrophobic properties.

In some embodiments the weather resistant fabric further comprises an underlining layer on the membrane layer. The provision of an underlining, such as fleece, on the membrane layer makes the fabric more comfortable to wear.

Preferably the shell fabric is a cotton fabric or a polyester fabric.

Cotton and polyester fabrics are suitable for the shell fabric layer.

According to a second aspect of the present invention there is provided a method of manufacturing a provided a weather resistant fabric comprising a shell fabric layer having first and second surfaces, the method comprising the steps of:

i) forming a shell fabric layer comprising internally an elastomeric barrier spaced from the first and second surfaces; and ii) applying a hydrophobic breathable membrane layer to a surface of the shell fabric layer.

Preferably the method of forming the shell fabric layer comprising internally an elastomeric barrier spaced from the first and second surfaces comprises the steps of:

i) applying an elastomeric polymer to the shell fabric layer so as to provide a layer of elastomeric polymer internal to the shell fabric layer;

ii) removing excess elastomeric polymer from the shell fabric layer such that the elastomeric polymer layer is spaced from the first and second surfaces of the shell fabric layer.

Preferably the layer of elastomeric polymer is applied using a first blade.

Preferably the excess elastomeric polymer is removed using a second blade that contacts the shell fabric with a greater force than the first blade. Preferably the second blade contacts the shell fabric at a sharper angle than the first blade.

Preferably the elastomeric polymer is a liquid silicone rubber. Preferably the elastomeric barrier constitutes 5 to 30wt% of the shell fabric layer. Preferably the elastomeric barrier constitutes 1 0 to 20wt% of the shell fabric layer.

Preferably the membrane layer is laminated on a surface of the shell fabric layer.

Preferably the membrane layer is a PTFE membrane.

In order that the present invention may be more fully understood a specific embodiment will now be described with reference to the attached drawings, of which:

Figure 1 shows a schematic cross-section through an untreated shell fabric; Figure 2 shows a schematic cross-section through a prior art shell fabric comprising a silicone barrier;

Figure 3 shows a schematic cross-section through a shell fabric comprising a silicone barrier formed in accordance with the present invention;

Figure 4 shows a weather resistant fabric formed in accordance with the present invention;

Figure 5 shows the weather resistant fabric of Figure 4 further including an underlining;

Figure 6 shows a schematic diagram of an apparatus adapted to form the shell fabric of Figure 3.

Referring to the drawings, Figure 1 shows a schematic cross section through an untreated shell fabric 1 . In the present embodiment the fabric is a 207 GSM cotton fabric, but any suitable woven fabric might be employed.

In accordance with the technology set out in international patent application no. WO8908555A1 such a fabric 1 may be treated with a silicone polymer so as to result in a silicone barrier fabric 2, a schematic cross section of which is shown in Figure 2.

As can be seen, silicone barrier fabric 2 comprises a silicone barrier layer 3, and an untreated fabric layer 4. Silicone barrier fabric 2 comprises a weather facing surface 5 and an internal surface 6.

In use in an item of weather resistant clothing weather facing surface 5 is designed to form the external surface of the item of clothing and internal surface is designed to face the body of the wearer of the item of clothing.

It will be apparent to a person skilled in the art that any weather facing surface may have further treatments applied to it or indeed might be laminated with a further material.

However, in the course of the present application the term 'weather facing surface' is intended to mean a surface that intended to face the external environment when the weather resistant fabric is in use, regardless of whether or not that surface has had further treatments applied thereto.

A major drawback of a prior art weather resistant fabric as shown in Figure 2 is that silicone barrier layer 3 runs through fabric 2 such that silicone polymer is present on internal surface 6. The presence of silicone polymer on internal surface 6 prevents the lamination of any further layers onto internal surface 6 owing to the poor adhesion qualities of surface 6 induced by the silicone polymer.

Thus we turn to the present invention and Figure 3. A shell fabric layer 7 is provided with and internal silicone barrier layer 8. Shell fabric layer 7 has a weather facing surface 9 and an internal surface 1 0. As can be seen, silicone barrier layer 8 is spaced from weather facing surface 9 by an untreated layer of fabric 1 1 . Furthermore, silicone barrier layer 8 is spaced from internal surface 10 by a substantially untreated layer of fabric 12. In the present embodiment silicone barrier layer 8 is formed from a liquid Silicone Rubber (LSR) sold under the brand name Silopren (RTM) LSR 201 0 TP3740 by Momentive Performance Materials (RTM). Layer of fabric 12 is referred to as 'substantially' untreated as (and it will be apparent from the method of manufacture of shell fabric layer 7 described below that) silicone barrier layer 8 is implanted in shell fabric layer 7 via internal surface 10 and then removed from layer 12. Thus, it will be apparent that residual silicone polymer may be found in layer 12, in contrast to layer of fabric 1 1 through which silicone polymer has not passed.

It will be apparent to a person skilled in the art that silicone polymer could be implanted in shell fabric layer 7 via weather facing surface 9, but in the present embodiment it is implanted via internal surface 10.

Thus, and turning to Figure 4, as silicone polymer is substantially not present at internal surface 10, a PTFE membrane 13 may be laminated thereto resulting in a weather resistant fabric 15 made in accordance with the present invention. In the present embodiment a PTFE film (the properties of which are discussed in Example 1 ) sold by Novotex (RTM) is employed, but it will be apparent that any suitable hydrophobic breathable membrane layer might be employed.

Turning to Figure 5 and weather resistant fabric 16 (a modified version of weather resistant fabric 15), it can be seen that when desired, depending upon the purpose of a weather resistant fabric, further layers may be laminated to PTFE film 13. In the present embodiment a fleece layer 14 is adhered to PTFE film 13 so as to form an underlining. The method of manufacture of shell fabric 7 of Figure 4 will now be described with reference to Figure 6. It should be noted that the method of manufacture described herein is a modified version of that described in international patent application no. WO8908555A1 , and is not intended to be a comprehensive explanation of the process. It is however intended to explain the inventive modification of removing silicone polymer from the fabric such that the resultant silicone barrier is spaced from both the weather facing and internal surfaces. Figure 6 shows a schematic view of an apparatus 17 adapted to manufacture shell fabric 7 from fabric 25, which is fed into apparatus 17 from the left-hand side of Figure 6. Fabric 25 then travels through apparatus 1 7 from left to right as depicted by arrow A. Apparatus 17 comprises two pairs of motor powered rollers. The first pair constitutes the entry rollers 26, 27 and the second pair constitutes the exit rollers 28, 29. It is these pairs of rollers that progress fabric 25 through apparatus 17. Each roller turns in the respective direction indicated by the relevant arrow in Figure 6.

Apparatus 17 comprises free-turning rollers 18, 1 9, 20, which can be adjusted between different vertically positions. Apparatus 1 7 further comprises two blades 21 , 22. By means of controlled differentiated speed of the entry rollers 26, 27 (slower) and the exit rollers 28, 29 (faster), a tension in fabric 25 is created. This tension opens up the fabric and enables the implantation silicone polymer 23 inside the fabric at blade 21 and removal of excess silicone polymer 24 at blade 22 as discussed below.

By having rollers 18, 1 9 and 20 adjustable between different vertical positions it is possible to create different angles between fabric 25 and blades 21 , 22, which in the present embodiment of apparatus 17 are held in fixed positions. It is at blade 21 that silicone polymer 23 is applied to fabric 25. Silicone polymer 23 in gel form is delivered directly onto fabric 25 in front blade 21 from a static mixer/pump system (not shown). Blade 21 that is operable to push polymer 23 inside the fabric. Blade 22 is operable to remove excess silicone polymer 24 from the blade-contacting surface of fabric 25 and from below the blade-contacting surface of fabric 25 so as to result in substantially untreated fabric layer 1 2 as shown in Figure 3 and discussed above.

In order that blade 22 is operable to remove excess silicone polymer 23 from below the blade-contacting surface of fabric 25 rollers 18, 19 and 20 are positioned such that blade 22 applies a greater force than blade 21 to fabric 25. Rollers 18, 19 and 20 are also positioned such that fabric 25 contacts blade 22 at a sharper angle than it contacts blade 21 . When fabric 25 exits apparatus 1 7 it progresses to a stenter oven (not shown) for curing at 175 °C for 60 seconds.

Example 1 An example of method of manufacture of a weather resistant fabric in accordance with the present invention will now be set out.

Raw materials/components: · 100% Cotton fabric: yarn: CM40/2xCM40/2, fabric construction: 107 x 56 picks per inch (107 warp and 56 weft), fabric width: 150 cm, fabric weight 207 GSM (gram per meter square).

• Silicone polymer LSR 2010 (produced by Momentive (RTM).

• PTFE Film/membrane (produced by Novotex (RTM), thickness 35 micron, weight: 14 GSM, width: 162 cm, elongation: =/> 90%, waterproof: 20000 mmH ₂ 0, air permeability: > 0.50 cm3/cm2/sec The first step was to form the silicone barrier inside the fabric by means of an apparatus as described above. The speed of the fabric through the apparatus was 15 m/min and the fabric was under a tension of 158 kG. As will be appreciated, the different forces on the blades are significant in the method of manufacture, as in order to remove silicone polymer from a layer of the fabric adjacent the surface the force that the second blade applies to the fabric must be greater than the force that the first blade applies.

Blade 1 setting and parameters: sharpness (edge radiant angle): 0.0006mm, entry angle 40 °, exit angle 65 °, blade force 604 kg.

Blade 2 setting and parameters: sharpness (edge radiant angle): 0.0010mm, entry angle 50 °, exit angle 70 °, blade force 635 kg.

The fabric was then cured in an oven at 1 75 °C for 60 seconds.

Before the implantation of the silicone barrier the fabric weight was 207 GSM and after the silicone barrier was introduced the weight increased to 238 GSM.

The second step was to laminate a PTFE film onto the fabric comprising the silicone barrier. This process is well known in the art and further explanation is not required for a person skilled in the art.

Example 2

In a second example an identical process to that used in Example 1 was followed, except that the fabric used was 100% Polyester fabric with the following properties: yarn: 50D x 50D, fabric construction: 187 x 1 39 picks per inch (1 87 warp and 1 39 weft), fabric width: 150 cm, fabric weight 80 GSM.

The polyester fabric weight before the process was 80 GSM and after the silicone barrier was implanted its weight was 92 GSM. Example 1 & 2 Tests

The following standard tests were undertaken on average samples of coated and laminated fabrics, a sample of EPIC silicone barrier (RTM) fabric, and the fabric as formed by the process of Examples 1 and 2 of the present application.

ASTM D737 - air permeability; measurement unit - CFM. This test measures how much air may flow through the fabric and relates to the breathability of the garment.

ASTM 096 - Moisture Vapour Transfer Rate (MVTR); measurement unit - gr/m2/24hrs. This test is to measure a fabric's ability to allow diffusion of water vapour through the fabric.

EN 343 - waterproof test; measurement unit mm HH. This test is to measure a fabric's resistance to water penetration, tested under static water column pressure EN 29865 - Bundesmann Rain Test measures fabric protective factors (below a, b & c), in conditions which simulate a heavy rain and dynamic condition as would occur when person is wearing a garment and moving in the rain (like rubbing shoulders against the fabric - a movement which promotes penetration of water through the fabric). The factors tested are:

a. Absorbency - how much weight is gained due to water absorbency. b. Water repellency - more an aesthetic value rather than a true reflection of the rain protection.

c. Water penetration - measures how much water passed through the fabric during the test. Table 1 :

As can be seen, both the EPIC (RTM) fabric and the fabrics of the present invention greatly outperform the coated and laminated fabrics, but the fabric of the present invention is superior to the EPIC (RTM) fabric. This is because the presence of the PTFE film (not possible with EPIC (RTM) fabrics) provides for excellent waterproofing properties as demonstrated by test EN343.

The above embodiment is by way of example only. Many variations are possible without departing from the scope of the invention as set out in the appended claims.