WO2015094038A1

WO2015094038A1 - Tampon

Info

Publication number: WO2015094038A1
Application number: PCT/SE2013/051545
Authority: WO
Inventors: Lisa Palmqvist
Original assignee: Sca Hygiene Products Ab
Priority date: 2013-12-17
Filing date: 2013-12-17
Publication date: 2015-06-25

Abstract

The invention concerns a non-linting tampon and a method for producing such as tampon. The tampon comprises a core of absorbent fibers and a water soluble polymer on the outer surface of the core, the polymer being solid at temperatures below 38°C. The core is further free from a cover sheet.

Description

TAMPON

TECHNICAL FIELD

The present invention concerns a tampon free from a cover sheet.

BACKGROUND ART

Vaginal tampons are disposable absorbent articles sized and shaped for insertion into a women^'s vagina for absorption of body fluids generally discharged during the menstrual period. There are two basic types of tampons. The first type is a digital tampon which is inserted by the user^'s fingers. The second type is retained in an applicator which is used for insertion of the tampon. Tampons are usually made by folding or rolling rectangular strips of absorbent material into an elongated and generally rod-shaped core or body structure and then compressing the same. A withdrawal string is normally attached at the rolling or folding step. Cotton, rayon and viscose are commonly used absorbent materials in tampons. Rayon and viscose are wood pulp derivatives produced through several chemical processes. Tampons of cellulose have the problems inherent with all cellulose materials namely linting (tinting) of fibers. Fiber residues from the tampon may come loose from the tampon and be left in the vaginal cavity which can promote bacterial growth.

Tampons commonly have a fluid permeable cover or overwrap which substantially covers the absorbent member in order to prevent linting of fibers from the absorbent core during use. Such covers are normally of a

thermoplastic nonwoven or film material. Lately there has been health and environmental concerns regarding the use of synthetic fibers and materials in tampons as they have been shown to contain, even though in low concentrations, dioxins. Thus, there is a need for an environmental friendly yet lint-free tampon.

US495221 1 discloses the use of a wax coating in order to prevent fibre release from a tampon.

SUMMARY

The object of the invention is to provide an improved and alternative nonliving tampon. This is achieved by the tampon as defined in claim 1 and the method of claim 16.

The present invention relates to a tampon comprising a core of absorbent fibers and a water soluble polymer on the outer surface of the core, the polymer being solid at temperatures below 38°C, and wherein the core is free from a cover sheet.

According to one aspect the polymer is solid at temperatures below 40°C.

The polymer may be a synthetic or a natural hydrophilic or partly hydrophilic polymer.

The method of producing a tampon entails applying a water soluble polymer on the outer surface of a core of absorbent fibers, the polymer being solid at temperatures below 38°C, and wherein the core is free from a cover sheet.

According to one aspect the polymer is applied on the core by a spraying technique and according to another aspect the polymer is applied by a dipping technique. The polymer prevents fibres from being released from the tampon core while still allowing body fluid to enter and being absorbed by the absorbent core structure. DETAILED DESCRIPTION

Water-soluble polymers are defined herein as polymers bearing sufficient hydrophilic functionality allowing for molecular dissolution in aqueous media at temperatures below 1 10^°C. The polymer should be in a solid state at temperatures below 38°C, or below 40 ^°C, in order to function as a non-linting agent when the tampon is in use.

A tampon "free from a cover sheet" is defined herein as a tampon without a cover material such as a nonwoven, cast, woven, knitted nettings, perforated and non-perforated film or film laminates covering the outer surface of the tampon core. Such cover sheets are added as a solid material entity to the core during production of the tampon and are normally of a thermoplastic material.

According to one aspect the polymer on the outer surface of the cylindrical tampon core, after solidification and/or the evaporation of solvent, is in the form of a porous layer having voids for body fluid to enter allowing for an enhanced absorption while still fixing individual fibres to the tampon surface.

The water-soluble polymer may be a synthetic or a natural hydrophilic or partly hydrophilic polymer.

The hydrophilic functional group of the hydrophilic or partly hydrophilic polymer may be a neutral, anionic, cationic, zwitterionic group, or a combination of such groups.

The polymer may be a homopolymer, block copolymer or a statistical copolymer. Synthetic hydrophilic polymers may be tailor-made to display a discrete range of properties. Acrylic acid is a convenient starting point for synthesizing water-soluble polymers such as polycarboxylates. Polyvinyl alcohol is a water-soluble synthetic polymer having excellent film forming and adhesive properties.

Water-soluble synthetic polymers may be based on a group selected from: poly(oxyethylene), poly(oxypropylene, poly(methacrylic acid), polyvinyl alcohol), polyvinyl acetate) and polyvinyl pyrrolidone) or a combination thereof.

Water-soluble polymers are widely found in nature. The polymer may be based on a polysaccharide selected from the group consisting of agar, dextran, guar gum, carrageenan, xanthan gum, chitosan, pectin, alginate, cellulose and cellulose derivatives. Cellulose derivatives may be selected from the group consisting of carboxy methyl cellulose, hydroxy ethyl cellulose and ethyl hydroxy ethyl cellulose. The absorbent fibers of the core may be selected from cotton, rayon and viscose, or mixtures thereof. The core of absorbent fibers may be free from binders.

The concentration of the polymer on the core surface may be 0.01 -0.3 mg/mm² According to another aspect the concentration of the polymer on the core surface may be 0.01 -2 mg/mm². According to a further aspect the concentration of the polymer on the core surface may be 0.015-1 mg/mm².

The tampon may comprise an elongated generally rod-shaped absorption core having an insertion end and a withdrawal end and having a withdrawal string extending from the withdrawal end. The tampon length may be 30-70 mm, and may be 40-50 mm. In order to facilitate insertion, the core may be bullet shaped with a rounded or tapering insertion end. The core may have a flat withdrawal end surface. The core of absorbent fibers may be a rolled rectangular card band which may be optionally compressed. A withdrawal string may made from a material having high tensile strength and may firmly be attached to the tampon body by being wound internally in the absorption body or by being welded, glued or sewn to the absorption body. A withdrawal string may be made from a non-absorbent and non- wicking material.

The method of producing a tampon comprises: applying a water soluble polymer on the outer surface of a core of absorbent fibers, the polymer being solid at temperatures below 38°C, and wherein the core is free from a cover sheet.

The polymer may be applied as a polymer solution or a melt of the polymer. The polymer may be applied by an application technique such as a spraying technique or by a dipping technique. In case of using a spraying technique the polymer may be added as a fine mist, wherein the polymer penetrates only the outermost surface of the tampon. The spraying distance depends on i.a. spraying equipment such as spraying nozzle and may be adjusted by the man skilled in the art.

The polymer may be applied before or after a compression of the core. To avoid swelling of the core, the polymer may be applied and the surface dried prior to a compression of the core.

A compressed core may have compression lines. The compression of absorbent fibres to a compressed core may be made by hot compression or cold compression as found suitable. In order to create stable, permanent compressed structures an elevated temperature will usually be required. Temperatures of 70°C or more may be used in hot compression. As is well known by the person skilled in the art, other parameters of importance are the applied pressure, the pressing time and the composition of the material in the tampon. These parameters interact so that at higher temperatures shorter pressing times may be used. With commonly used tampon materials and pressing methods a temperature of around 100°C and a forming time of 0.2-5 seconds may be suitable in order to obtain a stable compressed structure such as an indentation or a wave shaped compression line. Parameters such as pressing times, temperatures, and pressure may be selected as is known in the art in order to obtain the desired effect.

DETAILED DESCRIPTION OF FIGURES

Figures 1 -3 show pictures of tampons from the example described herein.

The invention will be described more closely below by experimental examples, but should not be construed as limited to the examples shown herein.

Examples

Natracare® tampons, cotton tampons with no core cover sheets, were used for the test. The tampons were prepared for the test by removing the top half of the quick wrap from the tampons. A test solution was prepared by dissolving 20 g of Polyvinylpyrrolidone in 100 g of water. The solution was stirred for at least 30 minutes. The test solution was added to the tampons by spraying the prepared 20% solution of Polyvinylpyrrolidone onto the tampons. The tampons were weighed before and after the addition of the polymer and thereafter dried at 40^°C in a cabinet for 12 hours. The g/mm² of the polymer on the tampon was calculated from the concentration of the polymer solution, the weight of the liquid sprayed onto the tampon and the surface area of the tampon. A reference sample was sprayed with pure water. An 8.5 cm wide Parafilm®M (a plastic paraffin film) was taped up onto a table. The tampons prepared as above were tested for linting by grinding each tampon against the parafilm back and forth 8.5 cm on the parafilm in two cycles and with a slight hand pressure. An unused surface of the parafilm was used for each tampon. One untreated reference tampon was grinded in the same way as the treated tampons. After the grinding test a picture was taken of each treated and grinded tampon side by side with the grinded untreated tampon. Pictures of the tampons from the test are shown in figures 1 -3. The treated samples have a somewhat expanded structure due to the treatment with the liquids.

Sample Concentration Result Figu

No (mg/mm²) No

1 -^* lint 1

2 0.0097 lint 2

3 0.0191 no lint 3

^*Reference tampon sprayed with pure water. Samples 1 and 2 shown to the left in figures 1 and 2 respectively both showed linting after the grinding treatment. Linting is herein defined as filaments coming loose and/or sticking out from the core structure. Sample 3 in figure 1 did not show any signs of linting. Polyvinylpyrrolidone has a melting point of 150-180^°C. Good results have also been achieved with Pluronic® such as F127 being a block copolymer of PEO/PPO having a melting point of 56^°C and a solubility in water at 25^°C of >10%.

Claims

1 . A tampon comprising a core of absorbent fibres, characterized by a water soluble polymer on the outer surface of the core, the polymer being solid at temperatures below 38°C, and wherein the core is free from a cover sheet.

2. Tampon according to claim 1 , wherein the polymer is solid at temperatures below 40°C

3. Tampon according to claim 1 or 2, wherein the core comprises absorbent fibers selected from cotton, rayon and viscose, or mixtures thereof.

4. Tampon according to any one of the claims 1 -3, wherein the polymer is a synthetic or a natural hydrophilic or partly hydrophilic polymer.

5. Tampon according to claim 4, wherein a hydrophilic or partly

hydrophilic functional group of the polymer is a neutral, anionic, cationic, zwitterionic group, or a combination of such groups.

6. Tampon according to any one of claims 1 -5, wherein the polymer is a homopolymer, block copolymer or a statistical copolymer.

7. Tampon according to any one of claims 1 -6, wherein the polymer is based on a group selected from: poly(oxyethylene), poly(oxypropylene), poly(acrylic acid), poly(methacrylic acid), polyvinyl alcohol), polyvinyl acetate), polyvinyl pyrrolidone) or a combination thereof.

8. Tampon according to any one of claims 1 -5, wherein the polymer is based on a polysaccharide selected from the group consisting of agar, dextran, guar gum, carrageenan, xanthan gum, chitosan, pectin, alginate, cellulose or cellulose derivative.

9. Tampon according to any one of the claims 1 -5, wherein the polymer is based on a cellulose derivative selected from the group consisting of carboxy methyl cellulose, hydroxy ethyl cellulose and ethyl hydroxy ethyl cellulose.

10. Tampon according to any one of claims 1 -9, wherein the concentration of the polymer on the surface of the core is 0.01 -2 mg/mm².

1 1 . Tampon according to any one of claims 1 -10, wherein the

concentration of the polymer on the surface of the core is 0.015-1 mg/mm².

12. Tampon according to any one of claims 1 -1 1 , wherein the

concentration of the polymer on the surface of the core is 0.015-0.1 mg/mm².

13. Tampon according to any one of claims 1 -12, wherein the core is free from binders.

14. Tampon according to any one of claims 1 -13, wherein the polymer is forming a porous layer on the surface of the core.

15. Tampon according to any one of claims 1 -14, wherein the core is a compressed body.

16. Method of producing a tampon comprising:

-applying a water soluble polymer on the outer surface of a core of absorbent fibres, the polymer being solid at temperatures below 38°C, and wherein the core is free from a cover sheet.

17. Method according to claim 16, wherein the polymer is applied as a polymer solution or a melt.

18. Method according to claim 16 or 17, wherein the polymer is applied by a spraying technique.

19. Method according to claim 18, wherein the polymer is applied as a fine mist.

20. Method according to claim 16 or 17, wherein the polymer is applied by a dipping technique.

21 . Method according to any one of the claims 16-20, wherein the core is a rolled card band.

22. Method according to any one of the claims 16-21 , wherein the polymer is applied before a compression of the core.