This invention relates to condoms. The use of condoms, both as contraceptives and as a means of protection against infection, has increased considerably in the recent past. This can be seen as being due to the emergence of health dangers associated with the use of other contraceptives, such as the contraceptive pill and IUDs, but mainly to increased concern about the possibility of infection during sexual intercourse, particularly by the AIDS virus.

Condoms are however regarded as inconvenient to use, particularly because of the necessity to put them in place in the period immediately preceding sexual intercourse. This problem tends to be greater the more sexually inexperienced the user of the condom is and therefore tends particularly to affect younger users. Moreover, a certain experience and dexterity on the part of the user tends to be necessary in order to put the condom properly in place. These factors tend to discourage the use of condoms by younger and sexually less experienced people who nevertheless tend to be at greater risk both of infection, particularly by the AIDS virus, and of unwanted pregnancy. The present invention provides a condom of which at least a portion comprises self-energising visible- light-emitting material.

Such a condom is much more readily handled in the dark since, after any energisation period necessary, it will spontaneously provide illumination of its immediate surroundings. It will therefore be more

easily put properly in place without it being necessary to provide more general illumination of the area of use. This is particularly advantageous in situations in which younger people often find themselves where such general illumination is not available or would attract undesired attention. In any event, the use of more general illumination can be a considerable disadvantage in that it can, at time it is needed, lead to an undesired loss of ambience or mood or to embarrassment, particularly in the case of younger and sexually inexperienced people.

The present invention can overcome these disadvantages associated with the use of condoms and thereby encourage their wider use. The spread of infection, particularly by the AIDS virus, and the occurrence of unwanted pregnancies can thereby be reduced. The condom of the invention moreover provides a certain novelty attraction for all users, whether sexually experienced or not. Further, it is apparent to the partner of the user, even in the dark, that the condom is properly in place. Reassurance as to its use is thereby obtained.

The light-emitting portion of the condom could be adjacent its open end, or include at least part of the annular bead normally present around the opening. If desired, an annular space within the bead could contain a light-emitting material. Instead or in addition, the space could be coated on its interior surface with the material. Otherwise a band of the material could extend, interrupted or uninterrupted, around the condom ad acent its open end.

Preferably however the light-emitting portion extends over a major part of the surface of the condom, more preferably over the entire surface, or substantially the entire surface.

Conveniently, the condom is formed from a material which incorporates an appropriate light-emitting substance in the body of the material and the present invention also provides a natural or synthetic rubber material incorporating in the body of the material at least one self-energising visible light-emitting substance. Such a material, preferably in the form of a film formed from a latex, can find application, other than in condoms, in, for example, diving wear and equipment, dinghies, life rafts, life jackets, marine cable and balloons.

Throughout this specification, the term "self- energising visible light-emitting material" covers materials such as luminescent materials, including chemiluminescent, bioluminescent and photoluminescent materials, phosphorescent and fluorescent materials, and all materials which emit visible light spontaneously, simultaneously with or subsequent to excitation by irradiation. The light-emitting material preferably has an emitted-light brightness of 1000 times the threshold of perception (ie 3.2 millicandellas per square meter) for at least 15 minutes, more preferably at least 30 minutes and even more preferably at least 60 minutes after completion of excitation.

Preferably the light-emitting material is an inorganic phosphor, more preferably a sulphide-type phosphor such as zinc sulphide or cadmium sulphide, each of which is advantageously copper-activated. Copper-activated zinc and cadmium sulphide have the advantage of a relatively long afterglow, i.e. the period over which visible light is emitted after irradiation of the material has ceased.

Other luminescent materials can nevertheless be used, for example that sold under the trade mark CYALUME .

The invention also provides a method of making a

self-energising, visible-light-emitting condom, the method comprising incorporating a self-energising, visible-light-emitting material into a liquid material capable of solidification into a condom film, and forming the film-forming material incorporating the light-emitting material into a condom.

Further, the invention provides a method of making a self energising, visible light-emitting condom, the method comprising forming a condom shape of condom film-forming material, coating the material with self- energising visible-light-emitting material, and adding a further layer of film-forming material to the coated condom-shaped material.

Coating can be accomplished by, for example, brushing, spraying or dipping.

Preferably, the film material is incompletely dry at the time of coating.

The formation of a condom from liquid film-forming material containing the light-emitting material can be accomplished by any conventional technique such as dipping an appropriately-shaped glass former into the liquid material, drying, repeating the dipping and drying if required, rolling the bead, drying, leaching in water and stripping from the former. An embodiment of the inve-ntion will now be described by way of example with reference to the drawing, of which the sole figure is a longitudinal sectional view of a condom.

The drawing shows a condom 1 of conventional shape and material, the condom having rolled bead 2 around its open end 3. The bead 2 contains a luminescent substance 4 which spontaneously emits visible light. Alternatively, the substance is coated on the surface of the interior of the bead. The condom is packaged in a sealed pack which is

torn open for use. After opening, the condom will emit light and illuminate at least the area immediately around it. This light is sufficient to facilitate deployment of the condom and also provides a visible reassurance to the partner of the user that it has in fact been placed correctly in place before intercourse takes place.

It will be appreciated that, in other embodiments, the luminescent material can be coated onto, or incorporated into, any other part, or the whole, of the condom.

EXAMPLE 1

The following example describes the incorporation of a luminous pigment into a natural rubber latex/ to produce a material from which a condom according to the invention can be made, the condom having a luminous portion extending over the entire surface of the condom. The natural rubber latex used was Qualitex PV latex (available from William Symington & Sons Limited of Bath House, 53-60 Holborn Viaduct, London EC1A 2ES). This is a pre-vulcanised cis-polyisoprene latex, preserved with ammonia in an amount of 0.7% w/w. The latex is particularly readily processed because it gives a vulcanised film simply upon drying. The latex conforms to the US Pharmacopoeia XX rabbit muscle implant test and is recommended for products such as feeding bottle teats and surgical tubings without addition of antioxidant normally being necessary.

The latex was used in combination with a luminescent pigment. One of the suitable pigments on the market is Crex luminous pigment green (obtainable from Blagden Chemicals Limited of AMP House, Dingwall Road, Croydon, Surrey, CR9 3QU). This pigment

comprises copper-activated zinc sulphide and has a long afterglow. The lumiphor becomes fully charged after two minutes exposure to UV light, daylight or artificial light and will continue to emit green light with a maximum intensity of 535nm for several hours after the excitation light has been extinguished. Afterglow brightnesses of 126, 31.3, 5.90 and 3.95 millicandellas per square meter have been observed at 3, 10, 30 and 60 minutes respectively after completion of excitation. The material has a period for decay to 100 times the threshold of perception (ie to 0,32 millicandellas per square meter) of 480 minutes. It is important, when this type of luminescent material is used, for the latex to be free from heavy metals and any other materials which may poison the luminescent material. As an indication of appropriate purity, it can be ensured that the latex film formed is water- white and transparent to UV radiation.

The Crex luminous pigment was incorporated into the Qualitex PV latex (previously found to have both purity-indicating properties just mentioned) by stirring. It is particulary important that grinding is avoided. The additional of 1 to 2% by weight of diglycol stearate greatly assisted suspension and re- dispersion of the pigment before use.

The following mixture was accordingly made by stirring

Qualitex PV latex (preserved with 0.7% w/w ammonia) 1,503 g diglycol stearate 18 g

After stirring

Crex luminous green 90 g

was added with further stirring. The mixture was then allowed to stand for 16 hours to allow air to come out of the mixture. Any pigment which settled during the period of standing was carefully stirred-up with a hand-held spatula and kept in suspension by slow mechanical stirring.

Condoms were the forms on a glass formed by the following procedure.

(1 ) Dip into the latex mixture (2) Dry for 2.5 minutes at 70°C

(3) Repeat (1 )

(4) Repeat (2)

(5) Roll the bead

(6) Dry for 2.5 hours at 70°C (7) Leach in water for 16 hours at room temperature

(8) Strip from former

( 9 ) Powder

In a commercial operation, the times and temperatures in steps (2), (4), (6) and (7) would be varied to suit plant requirements

EXAMPLE 2

In this example the luminous material was coated onto an incompletely-dried latex film already shaped into a condom on a suitable former. After coating a further layer of latex material was applied to cover the luminous material completely.

EXAMPLE 3

Example 1 was repeated using MR Revultex latex (a pre-vulcanised latex available from Revertex Limited of Temple Fields, Harlow, Essex) in place of Qualitex PV. The tensile stress and elongation at break of

condoms made by the method of this example were measured as specified in British Standard BS3704:1989. The following results were obtained on five unaged sample condoms.

Tensile Stress (MPa) Elongation at Break (%).

13.3 845 16.2 880 20.3 930

18.9 915

19.4 920

To test the effect of ageing, sample condoms were placed between two discs of aluminum foil and the disc edges sealed with latex adhesive. This simulated packaged condoms, which were then heated at 70 C for 2 days. The following results were then obtained.

Tensile Stress (MPa) Elongation at Break (%) 21.8 965 23.3 965

16.4 910

17.1 915

18.7 930

The above results indicate that condoms according to the present invention should be capable of compliance with BS3704:1989, although it should be noted that the British Standard specifies maximum acceptable failure rates over "large-batch sampling.