GB2165158A

GB2165158A - Sanitary product

Info

Publication number: GB2165158A
Application number: GB08523182A
Authority: GB
Inventors: Pamela Joan Williams
Original assignee: Smith and Nephew Associated Companies PLC
Current assignee: Smith and Nephew PLC
Priority date: 1984-09-27
Filing date: 1985-09-19
Publication date: 1986-04-09
Also published as: GB8523182D0; GB2165158B

Abstract

An elongate sanitary towel which employs a plastics barrier film within an external liquid pervious cover of plastics net which comprises smooth longitudinal ribs interconnected by fibrillated strands, which towel has a pair of longitudinally extending adhesive strips located on its non-body facing surface for attaching the towel to a supporting garment, which adhesive strips penetrate the cover of plastics net and bond it to the plastics barrier film to inhibit movement between them and processes for its preparation are described. <IMAGE>

Description

SPECIFICATION Sanitary product The invention relates to a sanitary towel and method for its preparation.

Conventional sanitary towels often employ a plastics barrier film within an external liquid pervious cover to prevent body fluid exudate penetrating to the bottom surface of the towel in use. The plastics barrier film used in these towels is typically a thin film of a polyolefine such as polyethylene. The external liquid pervious cover of such sanitary towels in use contacts the body of the wearer and therefore it is desirable that the cover has a "soft feel" to render the towel comfortable to wear.

Particularly suitable cover materials which have a "soft feel" are plastics nets of the type disclosed in British patent No. 1,548,855. Such plastics nets, which are typically nets of a polyolefine, comprise smooth longitudinal ribs interconnected by fibrillated strands. It has been found, however, that when a plastics net of this structure is used as an external cover of a sanitary towel, the plastics barrier film and in particular a polyolefine barrier film, will tend to slip and move in relation to the plastics net cover due to the slippery nature of the film and net surfaces. Such movement of the barrier film may cause the film to become creased or displaced and thus may lead to leakage of body fluid exudate from the towel in use.

It would therefore be an advantage to provide an economical means of inhibiting such movement between the barrier film and the plastics net cover. A sanitary towel employing such an economical means has now been found.

Accordingly the present invention provides an elongate sanitary towel which employs a plastics barrier film within an external liquid pervious cover of plastics net which comprises smooth longitudinal ribs interconnected by fibrillated strands, which towel has a pair of longitudinally extending adhesive strips located on its non-body facing surface for attaching the towel to a support garment, which adhesive strips penetrate the cover of plastics net and bond it to the plastics barrier film to inhibit movement between them.

The sanitary towel of the invention thus utilises adhesive for attaching the towel to a supporting garment and also to bond the barrier film to the net cover. Such a towel therefore employs a relatively economical means of inhibiting movement between the film and the net cover.

The longitudinally extending pair of adhesive strips can suitably be a pair of substantially straight, parallel strips which are preferably located substantially parallel to the side edges of the towel. Such a pair of parallel strips are preferably also located symmetrically with respect to the longitudinal axis of the towel.

The adhesive strips can be in an discontinuous form, for example in the form of broken or interrupted strips, but it is preferred that the adhesive strips are continuous strips.

The length and width of the longitudinally extending adhesive strips will normally be adapted to the size of the towel. The adhesive strips can have a length which is less than that of the length of the towel, however, it is preferred that the adhesive strips extend to substantially both ends of the towel, in order to maximisefixation of the barrier film. The length and ends of the towel as used herein means the length and ends of the thick portion of the towel.

The width of the adhesive strips used in the invention can suitably be 3mm to 7mm and can more suitably be 4mm to 6mm. Preferred adhesive strips used in the invention have a width of 4mm to 5mum.

The adhesive strips on the surface of the sanitary towel of the invention are preferably widely spaced apart in order to obtain a wide distribution of the bonded area. The distance between adhesive strips however, will normally be adapted to the width of the sanitary towel or the width of the crotch area of the undergarment to which the sanitary towel is to be attached. The distance between the adhesive strips, that is the distance between the inner edges of the strips, can suitably be equivalent to at least a quarter of the width of the towel, more suitably equivalent to at least a third of the width of the towel and can preferably be equivalent to at least a half of the width of the towel.

The distance between the adhesive strips of favoured sanitary towels is suitably 1 5mm to 40mm and is preferably 20mm to 35mm.

In an apt sanitary towel of the invention which has a length of approximately 235mm and a width of approximately 64mm, the parallel adhesive strips extend to both ends of the towel, and have a width of 4mm to 5mm and the distance between the strips is 32mm.

In another similar apt sanitary towel of the invention which has a length of approximately 260mm and a width of approximately 68mm, the parallel adhesive strips extend to both ends of the towel and have a width of 4mm to Smm and the distance between the strips is 34mm.

The adhesive strips of the sanitary towel of the invention bond the plastics barrier film to the net cover and also allow the adhesive attachment of the towel to a supporting garment. The weight per unit area of the adhesive strips should therefore be suitable for carrying out both these functions. The weight per unit area of the adhesive strips is suitably 50 to 200g/m2 and is preferably 70 to 1 60g/m2.

The adhesive strips will normally be covered by one or more release protectors. A preferred release protector comprises a single sheet of, for example, a rectangular shape, which has a size adapted to cover both adhesive strips. Alternatively, each adhesive strip can be covered by separate release protector strips. These release protector strips or sheets can conveniently be longer than the adhesive strips to provide an overlap at one or more ends of adhesive strips to facilitate their removal from the surface of adhesive strips.

Suitable release protectors include papers, plastic coated papers and films provided with a silicone release coating.

An apt silicone coated release protector is known as Lotec 15 (available from Lotec Paper Ltd.).

The adhesive used in the invention will normally be a pressure sensitive adhesive. The pressure sensitive adhesive can be any of the pressure sensitive adhesives conventionally used on a sanitarty towel to allow attachment of the towel to a supporting garment.

Such adhesives, however, should preferably of a type which is capable of being applied in a fluid form to the surface of a sanitary towel of the invention to facilitate penetration of the adhesive through the net cover and the formation of a bond between them.

Suitable adhesives of this type include hot melt adhesives and aqueous emulsion adhesives.

Suitable hot melt adhesives include adhesives which comprise a thermoplastic rubber such as a polystyrene - polyolefine - polystyrene block copolymer. Suitable block copolymer hot melt adhesives for use in the invention are disclosed in British Patent 1,555,531.

An apt hot melt adhesive for use in the invention is known a Dispomelt 581 available from National Adhesives.

Suitable emulsion adhesives include adhesives which comprise an acrylic copolymer. Suitable acrylic copolymer adhesive for use in the invention is disclosed in British Patent no. 1,377,575.

The sanitary towel of the invention employs an external liquid pervious cover of plastics net.

When used herein the term 'net' means a structure in which the ribs or strands and junctures are formed integrally, for example, during manufacture. Fibrillated strands are strands which have been wholly or partly split into fibrils or small fibres.

Suitable plastics nets for use in the invention are disclosed in British Patent No. 1,548,865, the disclosure of which is incorporated herein. These nets comprise straight, parallel, smooth, longitudinal ribs interconnected by fibrillated strands. Such nets have strength, porosity and softness properties which make them highly suitable for use as cover for a sanitary towel.

Suitably, the plastic nets used in the invention have a weight per unit area of 2 to 20g/m2 and preferably a weight per unit area of 4 to 1 2g1m2.

Suitably, the plastic nets used in the invention have a thickness of 0.030mm to 0.150mm and preferably a thickness of 0.040mm to 0.120mm. Favoured plastics nets comprise a blend of a polyolefine and incompatible polymer. Particularly favoured plastic nets comprise a blend of high density polyethylene and high impact polystyrene. Apt integral nets of this type include those available as net 909 (Trade Mark) grades A4, A7, H8C and DHM (available from Smith & Nephew Plastics Ltd.). Such apt nets have a weight per unit area of 5 to 11.5g/m2 and a thickness of 0.04mm to 0.120mm.

The plastics barrier film used in the invention is suitably any inert physiologically compatible plastics film which include films made of polyethylene, polypropylene, polyamide, polyvinyl chloride and polyester. Preferably the plastics film is a polyethylene or polypropylene film. The plastics film can suitably have a thickness of 0.005mm to 0.06mm and preferably a thickness of 0.015mm to 0.025mm.

An apt plastics barrier film for use in the invention is a low density polyethylene film having a thickness of 0.015mm.

The sanitary towel of the invention will normally comprise an elongate core of absorbent material such as comminuted wood pulp of fluff. The plastics barrier film will normally cover the non-body facing side of the core and preferably also the longitudinal sides of the core to inhibit leakage therefrom. The plastics barrier film can optionally be adhered, for example by lines of adhesive, to the absorbent core to inhibit movement between the film and the absorbent core.

The external plastic net cover of the sanitary towel of the invention preferably has overlapping portions on the non-body facing side of the towel. One or both of the adhesive strips located on the surface of the towel can advantageously penetrate the overlapping portions of the plastics net cover and thus provide an adhesive seal or seals to maintain the net cover in place on the towel.

The external plastic net cover and the plastic barrier film preferably extend beyond the ends of the towel where they can be conveniently sealed together, for example by heat sealing, adjacent to these ends.

The sanitary towel of the invention can optionally comprise a fleece for example a rayon fleece, which covers the body facing side of the absorbent core to render the towel more comfortable in use.

In another aspect, the invention provides a pro cess for the preparation of an elongate sanitary towel of the invention which comprises providing a pair of longitudinally extending adhesive strips on the non-body facing surface of a sanitary towel for attaching the towel to a supporting garment, which towel employs a plastics barrier film within an external liquid pervious cover of plastics net which comprises smooth, longitudinal ribs interconnected by fibrillated strands, which adhesive strips penetrate the cover of plastics net and bond it to the plastics barrier film to inhibit movement between them.

The materials used in the process of the invention can conveniently be the materials described hereinbefore in relation to the sanitary towels of the invention.

The pair of adhesive strips can be provided on the surface of the sanitary towel by directly applying the adhesive as a pair of strips by a conventional coating technique such as an extrusion, printing or hot melt technique. The adhesive strips can then be provided with a release protector sheet or strips. Alternatively, the pair of adhesive strips can be provided on the towel by an indirect method in which the adhesive as a pair of strips is first applied by a conventional coating technique to a release sheet, and then transferred to the surface of the towel by laminating the coated release sheet to the towel. Such a release sheet can conveniently be the release protector sheetforthe adhesive strips.

The adhesive used in the process of the invention is preferably an adhesive which can be provided in a fluid form, for example a hot melt or emulsion adhesive. Application of such preferred adhesives in a fluid form onto the surface of the towel will ensure that the adhesive strips penetrate the plastics net cover and bond it to the plastics barrier film.

In a less preferred process of the invention, the adhesive strips are subjected to heat and pressure, for example during the lamination of the release protector to adhesive strips or the adhesive coated release sheet to the towel to cause the adhesive strips to penetrate the net cover of the towel.

The adhesive strips can be applied to the surface of the finished towel or to the surface of a composite strip, comprising the barrier film and the net cover, at an intermediate stage during the manufacture of the towel.

The sanitary towel of the invention will now be illustrated by way of example only and with reference to the accompanying drawings in which Figure 1 shows a plan view of a sanitary towel of the invention Figure 2 shows an enlarged cross-section of the sanitary towel of Figure 1.

Figure 1 and 2 show a sanitary towel (1) which employs a plastics barrier film (2) within an external liquid pervious cover (3) of plastic net. The plastic net comprises smooth, longitudinal ribs (not shown) interconnected by fibrillated strands (not shown).

Sanitary towel (1) has a pair of adhesive strips (4) located on its non-body facing surface for attaching the towel to a supporting garment (not shown).

Adhesive strips (4) as shown in Figure 1 are a pair of parallel strips which extend longitudinally to substantially both ends of the towel.

In Figure 2, plastics barrier film (2) covers the face of an absorbent core (5) on the non-body facing side of the towel (1) and also the longitudinal side edges of the core (5). Plastics net cover (3) has overlapping portions (6,7) on the same side of the towel.

Adhesive strips (4) penetrate the overlapping portions (6,7) of the plastics net cover (3) and bond it to the plastics barrier film (2), thus inhibiting movement between the barrier film and net cover.

Adhesive strips (4) would normally be provided with a release protector in the form of a single sheet or a pair of strips. However, for the sake of clarity the release protector has been omitted from Figures q and 2.

The adhesive strips of the sanitary towel of the invention shown in Figures 1 and 2 not only allow attachment of the sanitary towel to a supporting garment, but also a bond to the plastics net cover to the plastics film. Such adhesive strips thus provide an economical means of inhibiting movement between the barrier film and the net cover.

Claims

1. An elongate sanitary towel which employs a plastics barrier film within an external liquid pervious cover of plastics net which comprises smooth longitudinal ribs interconnected by fibrillated strands, which towel has a pair of longitudinally extending adhesive strips located on its non-body facing surface for attaching the towel to a supporting garment, which adhesive strips penetrate the cover of plastics net and bond it to the plastics barrier film to inhibit movement between them.

2. A sanitary towel as claimed in Claim 1 in which the adhesive strips are continuous strips.

3. A sanitary towel as claimed in either of Claims 1 or 2 in which the adhesive strips extend substantally to both ends of the towel.

4. A sanitary towel as claimed in any of Claims 1 to 3 in which the distance between the adhesive strip is equivalent to at least a third of the width of the towel.

5. A sanitary towel as claimed in any of Claims 1 to 4 in which adhesive strips have a width of 4mm to 6mm and the distance between the strips in 20mm to 35mm.

6. A sanitary towel claimed in any of Claims 1 to 5 in which the adhesive strips have a weight per unit area of 70 to 160g/m2.

7. A sanitary towel is claimed in any of Claims 1 to 6 in which the adhesive strips comprise hot melt adhesive.

8. A sanitary towel as claimed in any of Claims 1 to 7 in which the cover of plastics net and the plastic barrier film both comprise polyolefine.

9. A sanitary towel as claimed in any of Claims 1 to 8 in which the cover of plastics net has overlapping portions on the non-body facing side of the towel and of one or both of the pair of adhesive strips penetrate the overlapping portions to provide an adhesive seal for the cover.

10. A processforthe preparation of an elongate sanitary towel of any Claims 1 to 9 which compriss providing a pair of longitudinally extending adhesive strips on the non-body facing surface a sanitary towel for attaching the towel to a supporting garment, which sanitary towel employs a plastics barrier film within an external liquid pervious cover of plastics net which comprises smooth, longitudinal ribs interconnected by fibrillated strands, which adhesive strips penetrate the cover of plastics net and bond it to the plastics barrier film to inhibit movement between them.