This invention relates to narrow fabrics and more particularly concerns narrow fabrics intended for use as part of a garment or appliance to be worn on part of the body of a wearer.
There have been a number of proposals for providing on narrow fabrics one or more areas of a friction-generating material which serves to assist in retaining a garment or appliance in position during wear. Generally, these proposals have been in the field of ladies hosiery, particularly relating to stockings intended to be retained in position without any external means of support.
There have been a number of proposals for providing a friction-generating material on a garment. In UK patent specification no. 1,171,063 there is described and claimed a stocking or the like wherein a support band is formed by diffusing into a portion of the fabric of the stocking a synthetic elastomeric material such as a silicone elastomer. The methods of application of the elastomeric material suggest that the resulting coating would be a wide continuous band.
UK specification no. 1,425,161 also describes a process for applying a silicone rubber material to a textile fabric garment. The process is concerned with relatively heavy duty applications such as waistbands of trousers and elasticated corsetry and employs a plurality of individual nozzles arranged to produced a product having a plurality of parallel beads of silicone rubber applied thereto.
A development of the above process is described and claimed in UK patent specification no. 2,190,018. In this process the friction-generating material is a room temperature vulcanising silicone rubber having an elongation of at least three times that of the yarn or fabric to which it is applied. The process includes contacting the coated yarn or fabric with steam and thereafter vulcanising the rubber.
UK patent specification no. 2,258,135 describes the application of a stripe of silicone material to the surface of a welt ring of a stocking and subsequently curing the silicone material. The object of the invention described and claimed in this specification is to avoid the step of attaching a separate strip of lace or braid to a stocking by applying the silicone material directly to the welt ring of a stocking.
German Patentschrift no. 666955 discloses a stocking including a thread of elastic material, the stocking including apertures which allow the skin of a wearer to enter the apertures due to the pressure applied by the elasticated material.
According to one aspect of the present invention we provide a narrow fabric intended for use as part of a garment or appliance to be worn on part of the body of a wearer, said narrow fabric being provided with one or more areas of friction-generating material characterised in that said narrow fabric is an "open" fabric and a film of friction-generating material is arranged to follow the structure of the fabric so that the film of friction-generating material exhibits a plurality of openings corresponding to openings in the fabric.
The term "narrow fabric" is intended to refer not only to fabrics falling within a strict definition as used in the textile industry but to any fabric which has a longitudinal dimension considerably greater than its lateral, or average lateral, dimension. In the context of stockings, the term narrow fabric is intended to include fabric produced on a small diameter circular knitting machine.
We have found, surprisingly, that the provision of a relatively large contact area does not, as would be expected, increase the irritation due to the prevention of exposure of the skin to atmosphere but tends to decrease the discomfort and irritation by spreading the load over a greater area and decreasing the load per unit area applied to the skin.
The use of friction-generating material in the form of a film has also been found to provide a superior holding performance, so that garments tend to stay in position for longer periods. This, combined with the improved discomfort and irritation qualities, enables garments and appliances to be worn for longer periods which is an important consideration for the wearer.
The effective surface area of the film should be relatively large as compared with the thickness. The effective surface area of the film may be limited by the lateral dimensions of the narrow fabric but the average lateral dimension of film area should be at least 25 mm, preferably 30 mm, and more preferably 35 mm. Average lateral dimensions of 35 mm to 60 mm and especially 35 mm to 50 mm have been found to be particularly advantageous.
The thickness of the film should be controlled and it is preferably substantially uniform throughout. Whilst some variation in thickness is acceptable any tendency for the variation in thickness to resemble a plurality of beads should be avoided in order to take full advantage of the invention.
The average thickness should not exceed 0.5 mm, preferably 0.3 mm, more preferably 0.2mm. Average thickness of 0.1 mm to 0.3 mm, especially 0.15 mm to 0.25 mm have been found to be particularly advantageous.
Whilst the film may be continuous it is not necessarily so and it may be interrupted in a longitudinal or a transverse direction. It is, however, necessary that the applied friction-generating material should be in the form of a relatively thin film and the interruptions should not be such as to divide the applied material into one or more beads.
Thin films are believed to have an advantage in that they contribute less to the resilience of the coated fabric than relatively thicker beads or layers of friction-generating material and this is considered to be one of the factors in reducing the discomfort to the wearer.
The friction-generating material is preferably a silicone elastomer and more preferably is a heat-curable silicone elastomer. Conveniently, the viscosity of the uncured silicone elastomer is 50,000 to 150,000 MPas.
The invention includes a process for producing a narrow fabric intended for use as part of a garment or appliance to be worn on part of the body of a wearer, which comprises extruding a film of a curable friction-generating material onto a length of narrow fabric and curing the resultant film in situ on the fabric.
Conveniently, the narrow fabric is fed past a longitudinally stationary extrusion head.
In a modification of the invention, the film is applied to an "open" fabric and is arranged to follow the structure of the fabric so that the film of friction-generating material exhibits a plurality of openings corresponding to openings in the fabric.
Such a structure of film has many advantages. In addition to providing a reduced resilience for given film dimensions, the openings provide access for air to the body of the wearer, both factors contributing to improved comfort for the wearer. The structure also improves the aesthetic quality of the fabric in that the film is virtually invisible from the reverse side of the fabric.
It should be emphasised that not all the openings in the fabric need to have corresponding openings in the film of friction-generating material. For example, where the fabric is a lace it will usually comprise a design which will include a variety of openings of different shapes and sizes arranged in a pattern.
Openings in the film of friction-generating material will normally only correspond to the larger openings in the lace fabric and the film will be continuous in the regions of relatively smaller openings. Since these openings are relatively small the aesthetic appearance of the fabric is not adversely affected to any great extent.
According to a further aspect of the invention we provide a process for producing a narrow fabric intended for use as part of a garment or appliance to be worn on part of the body of a wearer, which comprises extruding a curable friction-generating material onto a length of narrow fabric characterised in that the friction-generating material is extruded as a film and the narrow fabric is an "open" fabric having a plurality of openings therein, one or more jets of gaseous medium are directed onto the fabric in the region of the extruded film so as to produce openings in at least the areas of openings of relatively larger dimension in the fabric and curing the resultant film in situ on the fabric.
The narrow fabric having a plurality of openings therein may be a lace.
The or each jet is preferably relatively wide in comparison to it's length, the width of the jet being determined by the lateral area of the fabric in which it is desired to produce openings in the film. The gas is conveniently air and is preferably comparatively dry clean air since contaminants may adversely affect the curing of the friction-generating material.
The or each jet of gas may be operated so as to act on only selected areas of a fabric where an open structure is required.
According to another aspect of the invention we provide apparatus for producing a narrow fabric intended for use as part of a garment or appliance to be worn on part of the body of a wearer the fabric being an "open" fabric the apparatus comprising means for moving said fabric past an extrusion head and means for supplying a curable friction-generating material to said extrusion head, characterised in that the extrusion head is arranged to produce a film of material and in that a nozzle is arranged downstream of the extrusion head, said nozzle being arranged to direct jets of gas onto the fabric in the region of the extruded film to produce openings in the film corresponding to openings in the fabric.
The invention is hereinafter further described with reference to the accompanying drawings, in which-
Referring to Figure 1, the fabric 10 is a stretch lace intended for attachment to the top of a stocking. A continuous film 11 of a heat-cured silicone elastomer is applied thereto. The transverse dimensions of the particular embodiment shown are: fabric: 70 mm and film 40 mm with the film thickness being constant at about 0.15 mm.
An apparatus suitable for carrying out the process is shown schematically in Figure 2. A length of narrow fabric 10 such as lace fabric, is fed continuously from a supply reel 20 to a take-up reel 24. A dry heat-curable silicone elastomer is fed from a supply chamber 21 to an extrusion head 22 which is arranged to extrude a film 11 of the heat-curable silicone elastomer onto the surface of the fabric 10.
The silicone elastomer film is cured as it passes through the curing station 23.
The product shown in Figure 3 comprises a length of stretch lace 10 having openings 12 of relatively large dimension. In the regions 13 of these relatively large openings it will be seen that the film 11 is confined to the textile material surrounding the openings whilst in the region 14 the openings are relatively small and the film is continuous.
Figure 4 is a detail showing the provision of a nozzle 41 for producing a jet of air 42 which is directed from the underside of the fabric 10 in the region of the extrusion head 22 so that the desired openings in the film of friction-generating material are produced before the material is cured.