This invention relates to a hairdresser's aid and, more particularly, to a stiffened masking sheet of flexible material for masking selected strands of a head of hair from other strands of hair, while the selected strands are treated, such as by being subjected to a setting process and/or to bleaching or colouring process.

Masking sheets are generally known in the hairdressing art. For example, GB2140682 discloses a masking sheet. The prior art masking sheet is illustrated in Figures 1 to 3. Here there is shown a rectangular elongate sheet 1 comprising a rectangular panel 2 of white substantially opaque plastics material and a rectangular panel 3 of substantially transparent plastics material. The panels 2 and 3 are of substantially equal area and are welded one to another along a common edge, or co- extruded, to form a transversely extending hinge 4. An upper transverse marginal edge portion 5 of the panel 2 is joined to an adhesive tape 6 having pressure sensitive contact adhesive applied to a surface thereof, which tape has a margin 7 free of adhesive.

In use, strands of a head of hair are selected by a technique known as "weaving" and the panel 2 is placed under selected strands of hair, as shown at 8 in Figure 3, of a head of hair 9 such that the margin 7 is located adjacent the scalp of the head 9. The adhesive tape 6 adheres to the selected strands of hair 8 adjacent the scalp such that the sheet 1 is located under and relative to the selected strands of hair 8.

The selected strands of hair 8 subsequently are coated with a liquid colouring substance (not shown) and the panel 3 is folded about the hinge 4 and is superimposed on the panel 2 with the selected strands of hair 8 located there between, a transverse marginal edge portion of the panel 3

adhering to the marginal edge portion 5 of the panel 2 by means of the adhesive tape 6 such that a margin 10 of the panel 3 is located adjacent the margin 7.

In this manner, the selected strands of hair 8 are located within an envelope defined by the panels 2 and 3, the hinge 4 and the adhesive tape 6, as shown at 11 in Figure 3, and are thus isolated from adjacent strands of hair while colouration of the selected strands of hair is completed.

It will be seen that this method involves the step of placing panel 2 under selected strands of hair 8. A hairdresser will do this by lifting of the selected strands of hair 8 with one hand, whilst using the other hand to place panel 2. It has been found that the panel will crumple as it is placed under the selected strands of hair 8. This believed to be because the panel of the known masking sheet is not sufficiently stiff longitudinally.

GB 2140682 discloses stiffening panel 2 by making margin 7 and adhesive tape 6 less flexible. However this does not solve the problem. It also suggests making panel 2 thicker. However, this substantially increases the costs of manufacture as well as making the masking sheet more difficult to mass produce.

A way to ameliorate these problems has been sought.

According to the present invention, there is provided a hairdresser's masking sheet of flexible material for masking selected strands of a head of hair from other strands of the hair while selected strands are treated, wherein the sheet comprises a substrate of flexible material and an adhesive portion whereby application of the adhesive portion to a portion of the head of hair selectively and removably unites the sheet with the

strands of the portion of hair thereby brought into contact therewith characterised in that the sheet comprises a stiffening strip so as to provide the sheet with longitudinal stiffness.

It has surprisingly been found that the inclusion of the stiffening strip is sufficient to overcome the problem with the masking sheet crumpling on application but without substantially increasing the costs of manufacture or making the masking sheet difficult to manufacture.

The stiffening strip is preferably positioned adjacent the adhesive portion and, more preferably, is positioned parallel to the adhesive portion. The advantage of positioning of the stiffening strip adjacent the adhesive portion is that this arrangement particularly enhances the longitudinal stiffness of the masking sheet. This is because in the prior art masking sheet, the join between panel 2 and adhesive tape 6 would appear to act as a hinge. In this way, the join facilitates the crumpling of the prior art masking sheet when it is applied to a person's head. In contrast in the present invention, the arrangement of the stiffening strip next to the adhesive portion prevents the formation of a hinge but instead provides longitudinal stiffness, particularly by laminating the adhesive portion to the substrate.

According to the present invention, there is further provided a method of manufacturing a masking sheet, which method comprises providing a strip of adhesive plastics material, providing a first panel of plastics material, placing the first panel on the strip of adhesive plastics material, such that the panel overlaps the strip and such that a stiffening strip is formed where the panel overlaps the strip wherein the stiffening strip has a depth sufficient to provide the sheet with longitudinal stiffness.

The method of the invention preferably includes the steps of providing a second panel of plastics material. joining the first panel of plastics material to the second panel of plastics material such that the join between the two panels acts as a hinge.

The invention will now be illustrated by way of example with reference to the Figures of the accompanying drawings in which:

Figure 1 is a plan view of a prior art sheet;

Figure 2 is a cross-section of the sheet shown in Figure 1 when in use;

Figure 3 is a diagrammatic representation of the sheet shown in Figure 1 in use;

Figure 4 is a plan view of a sheet according to the present invention; and

Figure 5 is a schematic view of the method according to the present invention for preparing a sheet according to the invention.

Referring now to Figure 4 of the .drawings, there is shown a rectangular elongate sheet 100 comprising an adhesive portion 160, a rectangular panel 120 of white substantially opaque plastics material and a rectangular panel 130 of substantially transparent plastics material.

The adhesive portion 160 is provided by adhesive tape indicated generally at 170. Panel 120 is placed on adhesive tape 170 such that panel 120 overlaps with adhesive tape 170. The part of the adhesive tape 170 which overlaps with panel 120 provides a stiffening strip 180. Adhesive tape

170 is formed from substantially stiffer plasties material than that used to form panel 120 or panel 130.

The adhesive used in the adhesive portion 160 or in the adhesive tape 170 is optionally a water-soluble or water-dispersible adhesive such that the masking sheet 100 may be readily removed from a subject's hair by the washing step used to rinse away any treatment applied to the hair.

The ratio of the depth of the stiffening strip 180 (labelled as D 2 in Figure 4) to the depth of the adhesive portion 160 (labelled as Dl in Figure 4) is preferably from 0.5: 1, more preferably from 1 :1 to 3: 1, more preferably to 2: 1 ; most preferably the ratio of D2 to Dl is about 1 : 1 or about 1.4:1.

The ratio of the depth of the stiffening strip 180 D2 to the combined depth of panel 120 and adhesive portion 160 (labelled as D3 in Figure 4) is preferably from 1 :8 to 1 : 12, more preferably about 1 :10.

In one example of masking sheet 120, Dl is 1.8 cm, D2 is 1.8 cm and D3 is 18.9 cm. In a further example of masking sheet 120, Dl is 1.7 cm, D2 is 2.3 cm and D3 is 19 cm. In an additional example of masking sheet 120, Dl is 1.4 cm, D2 is 1.9 cm and D3 is 18.9 cm. In all examples, the depth of panel 130 is substantially the same as depth D3 and the width of the masking sheet is about 9.4 cm. These measurements for Dl , D2 and D 3 are accurate to within plus or minus 1 mm. In the prior art sheet illustrated in Figure 1, the measurement equivalent to depth D2 is about 0.4 mm. Thus the area on prior art sheet 1 which is adjacent to adhesive strip 6 which serves to link adhesive strip 6 to panel 2 does not function as a stiffening strip 180 because it lacks sufficient depth.

The panels 120 and 130 are welded together along their upper and lower edges (respectively) , or co-extruded, to form a transversely extending hinge 140. The panels 120 and 130 have the same width but panel 130

has a greater depth such that when it is pivoted about a hinge 140, it overlaps with panel 120 and its upper edge is substantially coincident with the upper edge of adhesive portion 160. Thus panel 130 can be used to protect the adhesive of adhesive portion 160 before use.

The masking sheet 100 may be used in the same manner as hereinbefore described for prior art masking sheet 1.

The preparation of masking sheet 100 is illustrated schematically in Figure 5. The first step comprises providing a suitable length of adhesive tape 170, and panels 120 and 130. The second step optionally comprises adhering panel 120 to adhesive tape 170 as shown by arrows 200 and then panels 120 and 130 may be welded together to form hinge 140 as shown by arrows 210. Alternatively of the first step comprises welding together panels 120 and 130 to form hinge 140 first and then adhering panel 120 to adhesive tape 170. As a further alternative, panels 120 and 130 and hinge 140 may be provided as a single co-extruded unit (not shown) which is then adhered to the adhesive tape 170 as shown by arrows 200.

Adhesive portion 160 is optionally provided with a release paper (not shown) such as silicone coated paper to protect the adhesive before use. Alternatively panel 130 may be folded over panel 120 and adhesive portion 160 to releasably protect the adhesive portion 160.