Patent Description:
As is known, plastic products are versatile and lightweight and can be produced at relatively low costs.

Currently, only around <NUM>% of plastics and plastic products on the global market are considered to be bio-based, compostable and/or biodegradable.

Most plastics continue to be produced from fossil fuels in a process that contributes to increasing greenhouse gas emissions along their value chain.

In fact, plastic pollutes throughout its life cycle, from its production to use through to its disposal.

Plastic recycling rates are low and plastic enters the environment through, for example, littering, improper waste management and wear and tear on products which can remain in the environment for many years and may potentially enter the food chain.

In light of the above, it is clear that any non-biodegradable plastic product which is used continually and intensely can be a significant source of environmental pollution.

In the case of feminine hygiene tampon applicators, these are essentially made up of a syringe, wherein the cylinder containing the tampon and the plunger for expelling the tampon from the cylinder are currently made of plastic, and so they are a significant source of environmental pollution.

Publication <CIT> discloses compositions based on polylactic acid, polybutylene succinate and polybutyrate for the production of hygiene tampon applicators.

The aim of the present invention is to eliminate the above-mentioned drawbacks relating to the prior art.

Within this aim, one object of the invention is to provide an applicator for feminine hygiene tampons made of a material that will not be a source of environmental pollution.

Another object of the invention is to provide an applicator for feminine hygiene tampons which, despite being made of a biodegradable and therefore nonpolluting material, offers the same functional characteristics as a conventional applicator made of plastic material.

A further object of the invention is to create an applicator for feminine hygiene tampons which is structurally the same as the applicators made of plastic material currently on the market.

These and other objects are achieved with the applicator of claim <NUM>. Preferred embodiments of the invention will be apparent from the remaining claims.

The characteristics and advantages of the invention will be more evident from the following indicative and not exhaustive description of preferred but not exclusive embodiments of the applicator for feminine hygiene tampons illustrated in the following figures, in which:.

With particular reference to the figures described above, the feminine hygiene tampon applicator of the invention is generically indicated with reference number <NUM>.

In particular, the applicator <NUM> is of the type suitable for applying a feminine hygiene tampon <NUM> and includes a syringe <NUM> for expelling the tampon, for example made of very pure cotton wool, or of mixtures of rayon and cotton and the like. The tampon <NUM> has a hanging thread <NUM> to facilitate its removal after use.

The syringe <NUM> has a cylinder <NUM> containing the tampon <NUM> and a plunger <NUM> for expelling the tampon <NUM> from the cylinder upon its application.

Advantageously, the cylinder <NUM> or the plunger <NUM>, or both, are made of a material that is both biodegradable and compostable.

Thanks to this technical solution, the syringe <NUM> is able to biodegrade in a specific medium (water, soil, compost) under certain conditions and in variable periods of time.

At the same time, the syringe is also compostable as it will biodegrade under the conditions of an industrial composting plant or an industrial anaerobic digestion plant with a subsequent composting stage.

This solution eliminates any environmental pollution.

In particular, the material used to make the plunger <NUM> and/or the cylinder <NUM> includes:.

In a preferred embodiment of the invention, the material for making the aforementioned components of the syringe <NUM> also includes talc and additives such as epoxidized soybean oil and/or acetyl tributyl citrate and calcium stearate.

In greater detail, the material that offers the best biodegradability performance within the scope of the applicator of the invention and with valid structural resistance properties includes <NUM>% to <NUM>% by weight of polylactic acid, <NUM>% to <NUM>% by weight of polybutyrate, <NUM>% to <NUM>% by weight of polybutylene succinate, <NUM>% to <NUM>% by weight of talc and <NUM>% to <NUM>% by weight of epoxidized soybean oil and/or acetyl tributyl citrate and calcium stearate.

A preferred example of composition of the material of the invention is set out below:.

The cylinder <NUM> of the applicator <NUM> of the invention has one end provided with flexible chamfers or tongues <NUM>, suitable for allowing the tampon <NUM> to gradually exit from the syringe <NUM>, in a unidirectional and frictional manner.

Said cylinder <NUM> has, on its opposite end, a grip collar <NUM> and inside it a circular groove <NUM> into which protuberances <NUM> present on the end of the plunger <NUM> snap engage.

On the same end there are also flexible fingers <NUM> which serve to push the tampon <NUM> uniformly out of the cylinder <NUM> of the applicator.

On the opposite end the plunger <NUM> has a raised collar <NUM> which facilitates its movement by the user.

To determine the aerobic biodegradability of the syringe <NUM> of the applicator of the invention, controlled compostability conditions in accordance with the UNI EN ISO <NUM>-<NUM>:<NUM> standards were applied.

The determination of Total Organic Carbon (TOC) was carried out in accordance with UNI EN <NUM>:<NUM> "Determination of total organic carbon (TOC) in waste, sludges and sediments".

Microcrystalline cellulose in powder form with a TOC equal to <NUM>% was used as a reference material.

In accordance with the UNI EN ISO <NUM>-<NUM>:<NUM> standard, the test is carried out by mixing the sample with mature compost in order to verify whether the microbial environment of the compost is capable of breaking down the organic fraction of the sample into CO<NUM>, water and biomass.

The inoculum consists of mature compost obtained from an industrial composting plant. The compost is sieved to eliminate the coarse fraction. The fine fraction obtained represents the inoculum for the test, whose volatile solids content must be greater than <NUM>% of the value of the total volatile solids.

The sample under analysis (or the reference sample) is mixed with the inoculum in a ratio of <NUM>:<NUM> (dry weight) and introduced into the reactor. The reactors are placed in an incubator at a temperature of <NUM> ± <NUM> for the entire duration of the test. The aerobic conditions are maintained by blowing ambient air into the reactors. Aerobic conditions allow the conversion of the organic fraction of the sample into CO<NUM> during the test. The air flow at the outlet of each reactor is sent to a gas analyzer which determines the concentration of CO<NUM> and the flow at the reactor outlets at regular time intervals. The rate of biodegradation is determined as the percentage of the theoretical initial organic carbon content of the sample that is converted into CO<NUM>.

The sample was cut and ground until a thin, homogeneous fluff was obtained.

Blank: three glass reactors (<NUM> liter capacity) containing the test mixture.

Reference sample: three glass reactors (<NUM> liter capacity) each containing approximately <NUM> of microcrystalline cellulose in addition to the test mixture.

Sample: three glass reactors (<NUM> liter capacity) each containing approximately <NUM> of sample in addition to the test mixture.

Test mixture: mature compost from an industrial composting plant mixed with an inert support (vermiculite, Sigma - Aldrich code <NUM>), <NUM> compost + <NUM> vermiculite (dry weight) for each reactor.

Moisture of the test mixture: maintained at <NUM>±<NUM>% throughout the test.

Through the use of aquarium pumps, ambient air is blown through silicone tubes into flow meters to regulate the flow which are placed before the reactor inlets. The air flows are maintained at values of approximately <NUM>-<NUM> liters/hour. The aerobic conditions allow the organic fraction of the sample to be converted into CO<NUM> during the test. The air is previously humidified by bubbling water set at the same temperature as the reactors.

At the reactor outlets, the air is conveyed through gas-impermeable pipes into a humidity recovery and elimination system. The dry air is then sent into an infrared gas analyzer which determines the concentration of CO<NUM> and the flow at regular time intervals. The percentage of biodegradability is calculated as the percentage of CO<NUM> produced compared to the theoretical total carbon content of the sample (total theoretical CO<NUM> production).

Temperature during testing: <NUM>±<NUM>.

CO<NUM> measurement: the CO<NUM> is measured twice a day for the first <NUM> days of testing, then at least once a day until the 45th day of testing. It is subsequently measured at least <NUM> days a week until the 90th day. The measurements are reduced to three times a week for tests which are extended for another <NUM> days.

Remixing and humidity restoration: for the entire duration of the test, the contents of the reactors are mixed once a week and water is also added if necessary (partially restoring the initial weight of the reactors). These operations are appropriately recorded.

Three different scales were used during the test:.

The dry weight is determined in an oven at <NUM>±<NUM>, <NUM> of sample are treated for one night, then the sample is cooled in a desiccator and weighed in accordance with UNI <NUM>:<NUM> "Compost - Classification, requirements and use criteria".

The volatile solids are determined on dry samples placed at <NUM> for at least <NUM> hours until the complete disappearance of black particles in accordance with UNI ISO <NUM>:<NUM> "Paper, cardboard and pulp - Determination of the residue (ash) after incineration at <NUM>", adopting a different temperature as required by EN <NUM>:<NUM>/AC:<NUM>.

The pH of the compost is measured using the HACH LANGE SensION+ PH3 pH meter, following calibration. The test is carried out in accordance with UNI EN ISO <NUM>-<NUM>:<NUM>, paragraph <NUM>, on a suspension of compost in deionized water with a ratio of <NUM>:<NUM> after mixing.

The total nitrogen content in the compost is evaluated by means of the Kjeldahl method in accordance with UNI <NUM>:<NUM> "Compost - Classification, requirements and use criteria", applying the modifications indicated for the "Velp Scientifica UDK <NUM> Distiller" instruments.

<NUM> of sample is digested (mineralization: Velp Scientifica DK8 heating digester) in the presence of K<NUM>SO<NUM>, Se, H<NUM>SO<NUM> concentrated for <NUM>' at <NUM>. After cooling, the digested fraction is distilled in the presence of NaOH and boric acid. The nitrogen trapped via boric acid is titrated as standard HCl. The results are expressed as %.

The concentration of CO<NUM> in the gas exiting the reactors is evaluated using a specific scanning system equipped with an NDIR detector for CO<NUM> analysis (Ecocontrol model EC100). The system measures and records the concentration of CO<NUM> and the flow exiting each reactor at pre-set time intervals. The CO<NUM> determination system is periodically calibrated using a standard gas mixture (CO<NUM>/N) certified by an LAT calibration center; the system's flow meter is also calibrated by an LAT center.

The TOC is evaluated by an external laboratory in accordance with UNI EN <NUM>:<NUM> and the test is accredited by Accredia.

During the test setup, the ground sample was clearly visible compared to the rest of the mixture and much more voluminous than that of the reference reactors. After about <NUM> days the color of the sample began to darken and the volume began to reduce appreciably. After approximately <NUM> days the sample had disappeared and both the appearance and volume were similar to that of the reference sample.

The total cumulative CO<NUM> production is shown in <FIG> for the blank, reference and sample reactors. The CO<NUM> production of the "Compact feminine tampon applicators EarthBi AB313_LT" sample in the first few days was lower than the production of the reference microcrystalline cellulose. After <NUM> days, the CO<NUM> production of the "Compact feminine tampon applicators EarthBi AB313_LT" sample increased rapidly, reaching and exceeding that of the reference at the end of the test.

The following table shows the quantity of CO<NUM> produced after <NUM> days of testing:.

<FIG> shows the curves of CO<NUM> produced (in grams) by the syringe of the applicator of the invention, in comparison with the reference microcrystalline cellulose.

The biodegradation percentages of both the sample under analysis and the reference are determined by the ratio between the quantity of gaseous carbon produced (CO<NUM>) compared to the initial organic carbon content of the sample input into the reactors. <FIG> shows the trends in the biodegradability percentages obtained with the different replicates for the sample and the reference. The biodegradability rate of the "Compact feminine tampon applicators EarthBi AB313_LT" sample at the beginning of the test was very low compared to that of the reference microcrystalline cellulose. After the halfway mark of the test, the biodegradability rate of the sample increased quickly, reaching the reference. At the end of the test the "Compact feminine tampon applicators EarthBi AB313_LT" sample reached an average biodegradation value of <NUM>±<NUM>%, therefore reaching a value ≥ <NUM>% which represents the limit required by the EN <NUM>:<NUM> standard Annex A. <NUM>/AC:<NUM>.

<FIG> illustrates the aerobic biodegradability trend, in controlled compostability conditions, for the material making up the syringe <NUM> in comparison with the microcrystalline cellulose sample.

The following table shows the percentages of biodegradability at the end of the test (<NUM> days), calculated with respect to the amount of TOC initially contained in the samples:.

The test results show that, after the <NUM>-day test, the material making up the syringe <NUM> of the applicator <NUM> of the invention reached an average biodegradation value of <NUM> ± <NUM>%, compliant with the EN <NUM>:<NUM> standard Annex A. <NUM>/AC:<NUM> (required limit value greater than or equal to <NUM>%).

For the production of the applicator of the invention, an injection molding process is used for the cylinder and plunger of the syringe with a material comprising at least polylactic acid, polybutyrate, polybutylene succinate and talc, preferably a material composed essentially of <NUM>% to <NUM>% by weight of polylactic acid, <NUM>% to <NUM>% by weight of polybutyrate, <NUM>% to <NUM>% by weight of polybutylene succinate, <NUM>% to <NUM>% by weight of talc and <NUM>% to <NUM>% by weight of epoxidized soybean oil and/or acetyl tributyl citrate and calcium stearate.

Claim 1:
An applicator for feminine hygiene tampons, said applicator (<NUM>) comprising a syringe (<NUM>) for expelling an absorbent tampon (<NUM>), said syringe having a cylinder (<NUM>) for containing said tampon and a plunger (<NUM>) for expelling said tampon from said cylinder, characterized in that said cylinder and/or said plunger are made of a biodegradable and compostable material which comprises <NUM>% to <NUM>% by weight of polylactic acid, <NUM>% to <NUM>% by weight of polybutyrate and <NUM>% to <NUM>% by weight of polybutylene succinate.