WO2012143946A1

WO2012143946A1 - An improved female condom and process of manufacturing the same using natural rubber latex

Info

Publication number: WO2012143946A1
Application number: PCT/IN2012/000278
Authority: WO
Inventors: Resmy Rachel THOMAS; Suja B; Nisha U; Preethalekshmi A P; Abi SANTOSH APREM
Original assignee: Hll Lifecare Limited
Priority date: 2011-04-20
Filing date: 2012-04-18
Publication date: 2012-10-26
Also published as: ZA201307698B; BR112013026894B1; AP2013007260A0; AP3716A

Abstract

The invention provides a new and an improved female condom product and a method for manufacturing the same. The female condom product assembly includes a tubular sheath (2), an exterior bead (3) and a retention device (4). The tubular sheath is manufactured by dipping process and an exterior bead is formed by rolling the tubular sheath itself. The bead has sufficient thickness such that it will not unroll. The ring shaped retention device is prepared by foaming process using foaming agents or by moulding process. The female condom is made from natural latex so that it is soft and very comfortable to use. It has highly elastic modules and good storage stability.

Description

AN IMPROVED FEMALE CONDOM AND PROCESS OF MANUFACTURING THE SAME USING NATURAL RUBBER LATEX

FIELD OF INVENTION

The present invention relates to a process for manufacturing prophylactic devices. More particularly, it relates to female condoms that act as a barrier for human contraception and prevention of sexually transmitted infections (STIs) and also relates to the process of their manufacturing using natural rubber latex.

BACKGROUND OF THE INVENTION

Condoms are devices used for both contraception and protection during intercourse against the transfer of infectious matters such as bacterial and viral microbes that cause venereal diseases. The continued increase in the incidence of HIV/AIDS has caused various health organizations to encourage people to increase the use of condoms during sexual intercourse and to prevent the further spread of the disease.

Male condoms are well known, barrier device that provide protection against unintended pregnancies and STIs. Male condoms, however generally require the male partner to initiate the use after an erection has been attained, thus frequently causing an awkward disruption of intimacy and foreplay. Additionally many women would prefer not to depend on their male partner to provide their protection. Male condoms are not preferred for a variety of additional reasons including reduced sensations for the male partner.

Problems associated with male condoms have led to the development of various forms of female condoms that a woman can pre-place in her vagina before intercourse. Usually cervical caps or conventional diaphragm are used to cover the vaginal region near the cervix. But the female condoms provide a tubular receptacle that extends along the length of the vaginal canal and extend upto some of the genitals surrounding the inserted penis and gives good amount of protection. Such devices advantageously empower a female to protect herself from unintended pregnancy and STIs without relying on her male partner.

Though female condoms provide a level of protection and advantage over conventional male condoms, they do not seem to be an ideal solution. Several difficulties have been identified in using female condoms. Some of the female condoms are difficult to use and others may be uncomfortable for some women. These problems may reduce the pleasure during the intercourse for both male and the female partner.

In some cases, the outside portion of the female condom may shift and_^ twist excessively before and during initiation of intercourse. This may require .the woman to hold the outside portion with one or both hands which can be disruptive and awkward. Another problem with the female condoms is the lack of stability of the condom within the vaginal canal. It may move around and fall partially out causing inconvenience to the user. The lack of stability compromises the barrier protection and makes both partners feel nervous and insecure during intercourse. The movement of the pouch with the penis also decreases the sensation of the male partner. Existing female condoms with plastic frames may damage the vulva.

U.S Pat Nos. 4,735,621 ; 4,976,273; 5,094,250; 5,490,519 and 5,623,946 to Hessel disclose a female condom having a tubular protective device with a closed end and an open end. The open end has an extending portion for keeping the condom to be stretched. Further, the ring of the material can be kept from unrolling by heating or by using an adhesive.

German Pat. No. 210413 to Hollmann discloses a condom like device having an outer ring that radially extends the opening of the condom and does not have a means for retaining the closed end of the device in the vagina. PCT/GB 2003/002503 to Pope discloses a female condom made up of synthetic nitrile latex as the sheath material, the retention device as polyurethane and the integral bead is formed by applying adhesive material to the rolling sheath. During usage, it may be noisy and have a plastic effect. Moreover, all synthetic material, polyurethane, nitrile rubber, silicon rubber, polyethylene are prone to Type IV allergies because of toxic chemicals used in the case compounding.

U.S. Pat. No. 4,945,923 to Evans et al. discloses a tubular contraceptive device worn by women to prevent the exchange of body fluids during intercourse. It has a tubular sheath made up of impermeable material with an open and closed end. The inner ring is designed to hold the bottom end of the device around the cervix of the user. This may result in slippage from its cervical anchor point, and twisting or displacement during use.

U.S. Pat. No. 7,322,358 to Tarn et al. discloses a female condom that includes a pouch made of resilient membranous material and a cling mechanism. The cling mechanism may include hydrophilic foam that will nestle into the user's vaginal tissue. Different elastomeric materials such as urethane, polyolefin, latex, silicone or thermoplastic materials are used for the production of both sheath and foam. Moreover, the foam is joined to the pouch by welding process only. U.S. Pat. No. 7,823,591 to Reddy et al. discloses a female condom which has a pouch with an open end, closed end and a tubular body. A retention device is attached to the tubular device by means of bonding or some other melting methods.

U.S. Pat. Application No. 20070265408 to Cornish et al. discloses a female condom with body formed by dipping and the bead is rolled off to form a cuff at the open end. U.S. Pat. No. 7,726,316 to Pope discloses a female condom that comprises a tubular sheath with nitrile coating produced by dipping process using a coagulant. It has an open end which acts as an exterior bead that is formed by rolling the tubular sheath. In addition, adhesives are 85 used for rolling and the retention device is made up of polyurethane material.

U.S. Pat. No. 5,325,871 to Reddy discloses a female condom having a pouch that can be inserted into the vagina. Here, the stability of the condom is obtained only by retention force that is achieved by placing the retention member in the vagina.

90

U.S. Pat. No. D603, 041 to Garg discloses a female condom (Cupid's) that has a tubular body with retention ring like structure. Cupid's female condom is made up of natural latex rubber having a sheath with open end and closed end. It has an outer plastic frame which is made from thermoplastic materials. The retention device is made up of polyurethane foam.

95 .

V'Amore's female condom manufactured by Reddy has a design similar to that of the REALITY condom with a shield shaped outer ring and a sponge retention inner pouch to lodge the condom in the distal region of the vagina near the cervix. However, it lacks stability within the vaginal cavity and does not assure closed table positioning of the outer shield. The 100 outer shield may damage the vulva during intercourse.

U.S. Pat No. 5,515,862 to Artsi et al discloses a flexible tube for inserting into the vagina, a shield to cover the pubic region and a semi-rigid ring. Adhesive has been applied on the shield which is close to the outer edge so that the condom will lie beyond the pubic hair line 105 of the user. However, the usage of adhesive may be allergic to some users and it is not preferred. Application of adhesive is an additional operation for the manufacturing of female condom, which may also improve the cost of the female condom.

U.S Pat No.7,047,975 discloses a Tensegrity-based female condom which provides high 1 10 degree of internal and external stability, the degree of stability may vary based on the user's anatomy.

Another type of female contraceptive device known as panty condom provides external stability but do not address the need for stability within the vagina. A pouch portion of the

1 15 panty condom inserted into the vagina-may pull inside out or twist or turn adversely. This affects the male partner's sensation and compromise the barrier protection. Air may get pumped into the vaginal cavity during the intercourse leading to some noise or discomfort to the user. After intercourse, device may turn inside out during withdrawal, thereby making a mess and increasing the potential of disease transmission and unintended pregnancies.

120 Additionally, the panty configuration may be objectionable to users for aesthetic reasons. Hence, there is a need to provide an improved female condom product with more comfort and reliability.

125

SUMMARY OF THE INVENTION

The present invention fulfils the above mentioned drawbacks of the prior art by providing a new female condom which is a cheaper one and that is soft in nature, simple to use and has 130 good stability.

The present invention provides a new improved condom product comprising a tubular sheath, an exterior bead and a retention device and also provides a process for manufacturing the female condom. The female condom is completely made from natural latex incorporated with 35 layered nanosilicates. One of the main disadvantages concerned with latex products is protein allergy. This problem can be prevailed over by the incorporation of nanosilicates (since the protein content in the latex dispersion is taken away by the nanosilicates particles). The tubular sheath is manufactured by two stage dipping process and the exterior bead is formed by rolling the tubular sheath itself. No adhesive is applied for rolling and beading of the

140 exterior bead.

Preferred process of the invention uses a special formulation which contains a perfect level of sulphur for adequate cross linking of chains. This cross linked structure helps to form a uniform bead of sufficient thickness so that the bead will not unroll after dipping and

145 vulcanizing. Due to this formulation, the exterior bead will not rupture due to moisture absorption or by air expansion. Here, no coagulant is used during the dipping process as in the case of synthetic latex. For synthetic latex, it is very difficult to get a uniform film without the use of coagulant in dipping process. Moreover, the layered nanosilicate dispersions are used to obtain desired stiffness, transparency and better control over residual

150 proteins.

Preferred process of the invention also uses an appropriate level of layered nanosilicate as filler that is added as fine dispersions during compounding.

155 In addition, the retention device of the female condom is prepared by the foaming process of compounded latex using foaming agents. After foaming, the latex is moulded into a ring or disc shape under sufficient temperature and pressure. This structure enables easy insertion of tubular sheath into the vagina. The retention device is sufficiently flexible for handling and it is stable in the vagina during intercourse. Alternatively, other materials like silicones,

160 thermoplastic materials like ethylene vinyl acetate and other elastomeric materials like santhoprene, EPDM etc. can be used by applying the processing methods such as injection moulding, compression moulding and transfer moulding. There are many advantages achieved by the female condom of the present invention when 165 compared with the conventional condoms. There is no need of external plastic frames as exterior ring , so the vulva will not get damaged during sexual intercourse. The material is soft and very comfortable to use since it is made from natural latex. It has high elastic modulus and good storage stability.

170 Other features and advantages of various aspects of the invention will become apparent with reference to the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

175 FIG. 1 is a perspective view of a female condom of the present invention. DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a new and an improved product and a process for the 180 manufacture of female condom from natural rubber latex (NR latex). The condom acts as a protective device for human contraception and prevents sexually transmitted infections (STIs).

Referring now to the invention in more detail, FIG. 1 illustrates a female condom assembly 1 185 that consists of tubular sheath 2, exterior bead 3 and retention device 4.

According to the present invention, the tubular sheath 2 is manufactured by two stage dipping process. The glass formers preheated at 70°C are cooled and dipped into the compounded natural latex. Then, the dipped formers are vulcanized in a hot air oven at 70°C for 1 hr. The . 90 resulted material is leached in water at 60°C and allowed to dry. Here, the coagulant is not required for dipping.

The exterior bead 3 of the present invention is formed by rolling the tubular sheath 2 itself and thus it becomes an integral part of the tubular sheath 2. Here, no adhesive is applied for 195 rolling and beading of the exterior bead 3. This is achieved by using a special formulation which contains a perfect level of sulphur for adequate cross linking of chains. This cross linked structure helps to form a uniform bead 3 of sufficient thickness so that it will not unroll after dipping and vulcanizing. In addition, the bead 3 is non-porous in nature and thus it will not get ruptured by air expansion or by moisture absorption.

200

According to the present invention, nanosilicates with a wide range of particle size can be used. More preferably, an appropriate level of layered nanosilicates having smaller particle size is added as fine dispersions during compounding. In latex, the hydration efficiency of silicate, aspect ratio of the nanosilicate platelet and polarity of the polymer decides the 205 composite properties.

The female condom assembly 1 of the present invention has improved mechanical properties, reduced permeability and decreased moisture absorption by the addition of nanosilicates. The incorporation of nanosilicate into a polymer matrix has shown a significantly improved 210 transparency besides reducing haze. Also, the stiffness of the exterior bead of the female condom improves by the addition of nanosilicate. This addition of nanosilicate will result in the considerable reduction of protein content of the female condom. Also, the addition of nanosilicate in the female condom reduces the cost by reducing the latex consumption.

215 The retention device 4 of the female condom assembly 1 of the invention is manufactured by the foaming process of compounded natural latex using foaming agents or by materials like Ethylene Vinyl Acetate (Thermoplastics), Silicones, Santhoprene, EPDM (Elastomeric) via injection moulding or compression moulding or transfer moulding. After foaming, the latex is moulded, preferably into ring or disc shape under sufficient

220 temperature and pressure. This structure enables easy insertion into the vagina. The retention device 4 is sufficiently flexible for handling and stable in the vagina during intercourse.

The female condom assembly 1 of the present invention exhibits numerous practical advantages when compared to other synthetic latex female condoms that are manufactured

225 with nitrile, polyurethane, silicone and polyethylene. The advantages, but not limited to the following, are (a) no need of external plastic frames as exterior ring and so the vulva will not get damaged during sexual intercourse (b) made from natural latex so that it is highly elastic, soft in nature and very comfortable to wear and use (c) good storage stability (d) cost- effective in the way that female condom assembly 1 of the invention can be used by common

230 people (e) manufacturing process is quite easy as it requires no additional operations like welding or adhesive joining (f) cross linked structure of the exterior bead 3 avoids to get unroll after dipping and vulcanizing stages (g) bead 3 is not ruptured by air expansion or by moisture absorption due to its non-porous nature (h) no plastic feeling (i) possibility of Type IV allergy is lesser in natural latex based female condoms

235

While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be 240 limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention as claimed.

245

Claims

WE CLAIM:

250 1. A new improved female condom product comprising:

a tubular sheath;

an exterior bead; and

a retention device.

The product according to claim 1, acts as a protective device for human contraception and prevents sexually transmitted infections.

A new improved process for manufacturing a female condom product, comprising: a tubular sheath produced by dipping;

an exterior bead formed by rolling; and

a retention device produced by foaming and moulding.

The process of claim 3, wherein the said female condom product is made from natural latex.

265

5. The process of claim 4, wherein the said female condom is highly elastic and soft in nature.

6. The process of claim 3, wherein the said female condom is manufactured using a 270 special formulation that contains adequate cross linking agents including sulphur.

7. The process of claim 3, wherein the said tubular sheath produced by dipping is a two stage dipping process in that a glass former is preheated at 70°C, cooled and dipped into the compounded latex; then the dipped formers are vulcanized in hot air oven at

275 70°C for 1 hour; the obtained material is leached in water and allowed to dry.

8. The process of claim 3, wherein the said retention device is manufactured by foaming process of compounded natural latex using foaming agents or thermoplastic materials like ethylene vinyl acetate, silicones, Santhoprene,

280 EPDM by means of injection moulding or compression moulding or transfer moulding.

9. The process of claim 8, wherein the said retention device is of ring or disc shaped and highly flexible for insertion into the vagina.

10. The process of claim 3, wherein the said exterior bead is formed by rolling the barrier wall of the pouch upon itself and acts as an integral part of the said tubular sheath.

1 1. The process of claim 10, wherein the said exterior bead has cross linked structure in such a way that it prevents the bead to unroll after dipping and vulcanizing.

12. The process of claim 10, wherein the said bead is not ruptured by air expansion or by moisture absorption.

13. The process of claim 3, wherein the said product is free of any coagulant material.

14. The process of claim 3, wherein the said product is not using any plastic material as frame for the exterior opening, results in no pain to vulva.

15. The process of claim 3, wherein the said female condom is manufactured using a special formulation that contains layered nanosilicates.

16. The process of claim 15, wherein the said female condom has considerable reduction in protein content.

17. The process of claim 15, wherein the said female condom has improved mechanical properties and highly reduced permeability.

18. The process of claim 15, wherein the said female condom has improved transparency.

19. The process of claim 15, wherein the said female condom reduces the cost by reducing the latex consumption.

20. The process of claim 15, wherein the said female condom increases the stiffness of the exterior bead.

21. The process of claim 15, wherein the said layered nanosilicate absorbs the moisture to avoid the rupturing of the said exterior bead