WO2024086901A1

WO2024086901A1 - Biodegradable elastomeric articles and methods for their production

Info

Publication number: WO2024086901A1
Application number: PCT/AU2023/051093
Authority: WO
Inventors: Khon Pu Foo; Chin Keong LIM; Nurshamila Binti Shaari BALAKRISHNA
Original assignee: Diptech Pte Limited; CRAM, James-Robert
Priority date: 2022-10-28
Filing date: 2023-10-27
Publication date: 2024-05-02

Abstract

The present application relates to biodegradable elastomeric articles and methods for their production. In particular, the application relates to a method for the production of a biodegradable elastomeric article, the method comprising: preparing a solubilised biodegradation additive using a pH increasing agent and optionally a dispersant or surfactant; preparing an elastomeric film-forming composition by combining an elastomer and one or more cross-linking agents with the solubilised biodegradation additive; dipping a former into the elastomeric film-forming composition to produce a layer of the elastomeric film-forming composition on the former; drying and/or curing the layer of elastomeric film-forming composition on the former to produce the elastomeric article; and removing the elastomeric article from the former. The application also relates to an elastomeric film-forming composition for the production of biodegradable elastomeric articles, and biodegradable elastomeric article including as prepared by the method and from the film-forming composition.

Description

Biodegradable Elastomeric Articles and Methods for their Production

RELATED APPLICATION

The present application claims the benefit of Australian provisional patent application No. 2022903210 filed on 28 October 2022, which is incorporated herein by reference in its entirety.

FIELD

The present application relates to biodegradable elastomeric articles and methods for their production.

BACKGROUND

Elastomeric articles, such as gloves, are produced in very high volumes across the world for use in hospitals and other environments. Such articles provide protection for the wearer of the article from contact with biological fluids, pathogenic microorganisms, viruses and other substances. Disposable elastomeric gloves form part of single-use “personal protective equipment” used by persons to minimise risk of contracting, e.g., COVID-19 through physical contact. Increased use of personal protective equipment has led to a large increase in the volume of such elastomeric articles being manufactured, and a large increase in waste disposal problems associated with the articles after their use.

There has been increased interest in recent times in options for manufacturing biodegradable versions of single-use elastomeric articles. However, the large-scale production of elastomeric articles that are biodegradable and have the required balance of physical properties is not straight-forward. An initial challenge is the short shelf-life of the solid particulate biodegradable agents - from the time of manufacture, these agents have only a short shelf-life of up to 6 months. After transport and during storage until its use is required, the efficacy of the reagent continues to reduce, due to its degradation in the environment due to contact with oxygen and other factors. In addition, once formulated into a composition ready for article manufacturing, the liquidsuspension formulation may be kept for an extended period of time during which it can suffer from further degradation prior to use. In particular, in glove-manufacturing processes, large holding tanks or vats of the elastomeric film dipping compositions are prepared, and after a variable-length residence time in the holding tanks, those elastomeric film dipping compositions are transmitted into the dipping tanks where the composition remains (with topping up) during the course of the continuous glovedipping process. It is common for pre-mixed blends of a sub-set of components ready for use in producing the complete formulation for the elastomeric film dipping composition to be prepared and held in the liquid holding-tanks, prior to final formulating of the complete composition. During this time period, some input reagents are subject to ongoing degradation when kept in holding tanks for a period of time, either as a single-component liquid suspension, or as a blend of components in liquid suspension. Some reagents can degrade quickly. This degradation can then impact on the qualities of the gloves produced from the compositions. This particularly applies to dipping compositions containing less common reagents, such as the reagents required to provide biodegradable properties to gloves.

To the knowledge of the inventors, only small production quantities of biodegradable gloves are currently being manufactured - possibly due to a lack of stability of the formulations for elastomeric film dipping compositions which adversely impacts on the ability to produce the gloves in large quantities. It would be desirable to be able to produce such gloves with a more reliable process with a reduction of, or without, wastage of the input reagents due to spoilage or other degradation problems with the blends stored in holding tanks.

The physical properties (i.e., the conventional physical properties, as distinct from the biodegradability properties) of the ultimate elastomeric article are also very important. While the articles must have sufficient biodegradability to reduce the waste disposal impact on the environment, the gloves must also maintain sufficient barrier properties and elastomeric film performance qualities, and should also maintain a sufficient shelflife to ensure that even after a period of time in storage prior to use, the gloves have good film and barrier properties when subsequently used. It would be unacceptable for the gloves to have a short shelf-life before the glove properties start to deteriorate, which would risk the safety of the person using the elastomeric articles.

SUMMARY

The applicant has developed a new method for the production of biodegradable gloves that involves the use of a new elastomeric film-forming composition, and new biodegradable gloves made therefrom. According to one aspect, there is provided a method for the production of a biodegradable elastomeric article, the method comprising:

- Preparing a solubilised biodegradation additive using a pH increasing agent and optionally a dispersant or surfactant;

Preparing an elastomeric film-forming composition by combining an elastomer and one or more cross-linking agents with the solubilised biodegradation additive;

- Dipping a former into the elastomeric film-forming composition to produce a layer of the elastomeric film-forming composition on the former;

Drying and/or curing the layer of elastomeric film-forming composition on the former to produce the elastomeric article; and

Removing the elastomeric article from the former.

It will be understood that the method may involve additional stages of dipping the former into an elastomeric film-forming composition for the production of additional layer(s) of elastomeric film-forming composition on the former. The additional dipping step(s) may precede or follow the dipping step referred to above. The formulation of the elastomeric film-forming composition for the additional dipping steps may be the same as or different to that used for the dipping step referred to above. For example, the elastomeric film-forming composition may contain the biodegradation additive, or it may be free of the biodegradation additive. As a consequence, it is possible for the biodegradable elastomeric article to be prepared with one or more biodegradable layers, and with or without one or more additional elastomeric film layer(s) that are free of the biodegradation agent.

According to a second aspect, there is provided an elastomeric film-forming composition for the production of biodegradable elastomeric articles, the elastomeric film-forming composition comprising the combination of:

- a solubilised biodegradation additive comprising a biodegradable organic compound dissolved in water with a pH increasing agent and optionally a dispersant or surfactant;

- an elastomer; and one or more cross-linking agents.

According to a third aspect, there is provided a biodegradable elastomeric article comprising the cured product of an elastomeric film-forming composition that comprises the combination of:

- an elastomer; and one or more cross-linking agents.

It will be understood that the biodegradable elastomeric article may consist essentially of the cured product of the elastomeric film-forming composition described above, or it may further comprise one or more additional elastomeric film layer(s) of a different composition. For example, the one or more additional elastomeric film layer(s) may be free of the biodegradation agent.

Also provided herein are biodegradable elastomeric articles produced by the method described above, or from the elastomeric film-forming composition described above. The biodegradable elastomeric articles in preferred embodiments are gloves.

Initial attempts to prepare biodegradable gloves were met with problems in terms of the stability of the input components for producing the biodegradable elastomeric filmforming composition, and the quality of the gloves produced. It was surprisingly found that by solubilising a biodegradable organic compound when forming the biodegradation additive component, an increased stability of that reagent was able to be achieved. This stability was aided by the presence of the dispersant or surfactant. Long-term stability (i.e., stability of at least at least 6 months, ) was able to be achieved. The increased stability of this reagent also had the benefit of enabling large- scale manufacture of biodegradable articles, such as gloves. In preferred embodiments, large-scale manufacture of biodegradable articles without loss of input reagents due to degradation (e.g., browning and/or precipitation) of those reagents in the lead-up to their use in the manufacturing process was able to be achieved. The method also allows, in preferred embodiments, for an elastomeric film-forming composition to be prepared that has an improved or optimised balance of properties (including biodegradation performance), with a minimum content of biodegradation agent. Expressed another way, the applicant found that it did not have to incorporate a higher amount of costly biodegradation agent into the elastomeric film-forming composition to account for a percentage of degradation of that reagent in the elastomeric film-forming composition over the time period between (i) formulation of the biodegradation agent in water, and (ii) production of the gloves. It was able to thereafter produce biodegradable gloves with good biodegradation properties, balanced with good elastomeric film properties.

BRIEF DESCRIPTION OF THE DRAWINGS

The present inventions will now be described in further detail with reference to the Figures which illustrate non-limiting examples of aspects of the inventions.

Figure 1 contains a schematic illustration of a biodegradable elastomeric article in the form of a glove in accordance with one embodiment of the invention.

Figure 2 is a plot of the biomethane potential test results for a biodegradable elastomeric article produced in accordance with one embodiment of the invention (Formulation 5), compared to a positive control, and formulations outside the scope of the present application (Formulations 1 and 6).

Figure 3 is a series of photographs showing the effect of biodegraded residue of the biodegradable nitrile glove sample in soil at (a) 10 mg/kg, (b) 100 mg/kg, (c) 1000 mg/kg, (d) 5000 mg/kg, and (e) 10,000 mg/kg on Triticum aestivum growth.

Figure 4 is a series of photographs showing the effect of biodegraded residue of the biodegradable nitrile glove sample in soil at (a) 10 mg/kg, (b) 100 mg/kg, (c) 1000 mg/kg, (d) 5000 mg/kg, and (e) 10,000 mg/kg on Brassica juncea growth.

DETAILED DESCRIPTION

The biodegradable elastomeric article and methods of manufacture according to embodiment of the present application are described in further detail below.

The biodegradable elastomeric article comprises an elastomeric film having one or more elastomeric film layers.

Where the biodegradable elastomeric article comprises more than one elastomeric film-layer, one layer, multiple layers or all layers of the elastomeric article may be a biodegradable layer. Such layers are prepared through the incorporation of the solubilised biodegradation additive into the elastomeric film-forming composition for producing that layer of the elastomeric article.

The preparation of the elastomeric film-forming composition for producing one or more layers of the biodegradable elastomeric article involves an initial step of producing a biodegradation additive that is incorporated into an elastomeric film-forming composition. This requires initial solubilisation of a biodegradable organic compound in water using a pH increasing agent and optionally a dispersant or surfactant to produce a solubilised biodegradation additive. In particular embodiments, this initial step may comprise dissolving a biodegradable organic compound in water using a pH increasing agent and optionally a dispersant or surfactant to produce a solubilised biodegradation additive.

It was found through extensive test work that the conventional solid biodegradation agents, of the type used in formulations described in the art, suffer from a poor shelf life and poor stability when formulated for use in biodegradable glove production.

Extensive trials were then conducted on a range of biodegradation agents and methods for improving their utilisation. Attempts were made to use starch as a form of biodegradable organic compound (specifically, a biodegradable polymer), but these were unsuccessful as it was found that the starch-based formulations would not achieve good dispersion and would cause thickening on being combined with water including in the presence of a pH increasing agent. This would then lead to problems with its incorporation into the elastomeric film-forming composition.

The applicant conducted further research and found that by selecting the use of water- soluble or water-miscible biodegradable organic compounds, and preparing a solubilised biodegradation additive with that reagent, it was able to achieve increased stability of the biodegradation additive. The stability was much greater than for the compositions in which the biodegradable organic compounds were not solubilised. Examples of such compositions that did not contain a solubilised biodegradable organic compound include those compositions based on starch, polylactic acid, or low- density polyethylene. The SR5300 biodegradation agent of ENSO Plastics is not soluble, and has a short shelf-life. This agent was not suitable for the preparation of the present-claimed solubilised biodegradation additive. In addition, the asserted biodegradation additives from other suppliers were also not able to be sufficiently solubilised and used in this form to produce an elastomeric product with the required elastomeric film properties combined with biodegradability. Solubilised biodegradation additive

In this section the essential and preferred components of the solubilised biodegradation additive are described. Also described is the preparation of the solubilised biodegradation additive. The preparation of the elastomeric film-forming composition from the solubilised biodegradation additive is then described separately, further below.

Biodegradable organic compound

The biodegradation additive comprises a biodegradable organic compound as a key component. A biodegradable organic compound is a compound that is able to be biodegraded by microorganisms. That is, the biodegradable organic compound is able to be broken down into smaller molecular weight components by the action of micro- and/or macro-organisms or enzymes. The biodegradation by microorganisms may be achieved in the presence or absence of oxygen. Those skilled in the art have a good working understanding of those organic compounds that have such properties.

The term “biodegradable organic compound” encompasses biodegradable polymers as a sub-class, although preferably, as described further below, only water-soluble or water-miscible biodegradable polymers are used.

The biodegradable organic compounds may be natural or synthetic. Examples of biodegradable organic compounds include disaccharides, oligosaccharides, polysaccharides, cyclic esters, polyesters, cyclic amides, polyamides, proteins and biopolymers, including lipid-derived biopolymers. Specific examples include lactose, gum arabic, pullulan, cyclic esters (lactones) such as E-caprolactone, cyclic amides (lactams) such as caprolactam, lignosulfonates, gelatin, salts of casein (e.g., sodium caseinate), cellulose derivatives (e.g., cellulose ethers), gelatinized starch, alginic acid salts (e.g., sodium alginate), polyaspartic acid, poly(p-dioxanone), polyvinylpyrrolidone, polyvinyl alcohol, and their mixtures or copolymers.

The preferred sub-class of biodegradable organic compounds is the biodegradable organic compounds with molecular weights of not more than 10,000 g/mol; preferably not more than 8,000, <6,000, <5,000, <4,000, <3,000, <2,000, <1 ,000 or <1 ,000 g/mol. In some embodiments, the molecular weight of the biodegradable organic compound is <500, <200 or <200 g/mol. In some embodiments, the biodegradable organic compound is not a polymer comprising more than 2 repeated units but rather is a polymer consisting of two units i.e., a dimer. The molecular weights of biodegradable organic compounds of the preferred sub-class will typically be at least 30 g/mol; preferably at least 40, >50, >60, >70, >80, >90 or >100 g/mol. Expressed as a range, the molecular weights of biodegradable organic compounds of the preferred sub-class are typically of from 30 g/mol to 10,000 g/mol; preferably from 40 to 8,000, >50 to <6,000, >60 to <5,000, >70 to <4,000, >80 to <3,000, >90 to <1 ,000 or >100 to <1 ,000 g/mol. That said, the specified lower and upper limits may be combined in ranges without restriction. In some embodiments, the molecular weight of the biodegradable organic compound is from >100 to <500, >100 to <200 or >100 to <200 g/mol.

Preferably, the biodegradable organic compound is a solid at 22°C. Such compounds typically have a molecular weight of least 60 g/mol.

Solubility is a key feature. Sufficient solubility of this component is found to be important in achieving the improved, i.e., long-term, stability of the reagents and dipping formulation, and production of biodegradable gloves with good biodegradation properties, balanced with good elastomeric film properties.

Preferably, the solubilised biodegradation additive is water-based; i.e. the solvent comprises water. Preferably, the solvent consists of water.

Accordingly, of the biodegradable organic compounds, the sub-class that is of specific utility in the present application is the water-soluble or water-miscible biodegradable organic compounds. These compounds are the compounds that are able to be dissolved or form miscible mixtures in water. In other words, they are able to form an aqueous solution. That is, water-soluble generally refers to a solid dissolving in water while water-miscible generally refers to a liquid forming a miscible mixture in water, both resulting in aqueous solutions. Hereafter, the term “aqueous solution” is used to refer to the production of a solubilised or miscible combination of the biodegradable organic compound in water. This is achieved without precipitation of the compound out of solution or the separation into two distinct phases under the conditions in which a solubilised biodegradation additive is prepared and used as described herein. Preferably, this is also achieved without forming a solution of which flow is prohibited (e.g., undergoes gelation, gelatinisation) under the conditions in which a solubilised biodegradation additive is prepared and used as described herein. By way of example, gelatinised starch is taken in present context to be an aqueous solution of which flow is prohibited. By way of further example, alginate which is ionically cross-linked to the point of gelation is taken in present context to be an aqueous solution of which flow is prohibited. Unless otherwise indicated and required for specific embodiments, solubility is assessed in water. Solubility is preferably assessed at ambient conditions. “Ambient conditions” may be defined as 22°C and about 1 atm. In other more specific embodiments, the solubility is assessed at the prevailing pH conditions of the solution into which the biodegradable organic compound is being dissolved, often being alkaline pH - e.g., an aqueous solution with a pH of 11 .0.

In general, and by way of example, the water-solubility of the biodegradable organic compound should be such as to enable at least 0.1 grams, and preferably at least 1 gram, of compound to be dissolved in, or to form a miscible combination with, 100 mL of water at 22°C (i.e. per decilitre). Preferably the solubility (or miscibility) is at least 2, 3, 4, 5, 10, 15 or at least 20 grams per decilitre of water at 22°C. Preferably, the solubility is rated as being at least “sparingly soluble” or above, as per the US Pharmacopoeia. This means that solubility is preferably at least 1 g/100ml at 22°C (“sparingly soluble” is 1 .0 to 3.33 g/100ml.). The solubility is more preferably at least “soluble” (3.33 to 10 g/ml), or at least “freely soluble” (10 to 100 g/100ml). A solubility classified as “very slightly soluble” (0.01 to 0.1 g/100ml) or less is not considered to be “soluble” as defined herein.

As mentioned, in preferred embodiments the solubility (or miscibility) of the biodegradable organic compound is assessed at the prevailing pH conditions of the aqueous solution so-formed. As the solubilised biodegradation additive contains a pH increasing agent, this is often, and is preferably, alkaline pH. In some embodiments, the biodegradable organic compound is soluble (or miscible) at a pH of 8.0. In some embodiments, the biodegradable organic compound is one that is soluble (or miscible) at a pH of 13.0. In some embodiments the biodegradable organic compound is soluble (or miscible) across the pH range of 11 .0 - 13.0. In some embodiments the biodegradable organic compound is soluble (or miscible) across the pH range of 8.0 - 12.0. In some embodiments, the biodegradable organic compound is soluble (or miscible) across the pH range of 10.0 - 12.0. In some embodiments, the biodegradable organic compound is soluble (or miscible) across the pH range of 8.0 to 13.0. In other words, in some embodiments the biodegradable organic compound forms an aqueous solution at a pH of 8.0, and/or at a pH of 13.0, and/or across the pH range of 11 .0 - 13.0, and/or across the pH range of 8.0 - 12.0, and/or across the pH range of 10.0 - 12.0, and/or across the pH range of 8.0 to 13.0.

Accordingly, in some embodiments the solubilised biodegradation additive has a pH of 8.0, and/or at a pH of 13.0, and/or a pH within the pH range of 11 .0 - 13.0, and/or within the pH range of 8.0 - 12.0, and/or within the pH range of 10.0 - 12.0, and/or within the pH range of 8.0 to 13.0.

Once incorporated into the elastomeric article, the biodegradable organic compound is prone to microbial attack, causing breakdown of the compound. Once this process commences, the inoculation of the polymeric material with the microorganism and resultant breakdown products and enzymes results in the commencement of attack on the elastomeric material itself. The commencement of this process is aided by the presence of a chemoattractant, and hence in preferred embodiments, the biodegradation agent further comprises a chemoattractant as discussed further below.

One or more biodegradable organic compounds may be used, selected from the classes detailed above. In some embodiments, a single type of biodegradable organic compound is used.

The preferred biodegradable organic compounds are water-soluble or water-miscible compounds; are capable of forming aqueous solutions. Examples include lactose, gum arabic, pullulan, 3- to 9-membered cyclic amides such as caprolactam, lignosulfonates, soluble salts of casein (e.g., sodium caseinate), soluble cellulose derivatives (e.g., hydroxypropyl cellulose), polyvinylpyrollidone, polyvinyl alcohol and their mixtures or copolymers. These tend to be at least slightly soluble and tend not to form an aqueous solution of which flow is prohibited under the conditions in which the solubilised biodegradation additive is prepared and used as described herein. More preferred biodegradable organic compounds are lactose, gum arabic, pullulan, 3- to 9-membered cyclic amides such as caprolactam, soluble salts of casein (e.g., sodium caseinate), polyvinylpyrollidone and their mixtures or copolymers. These tend to be at least well soluble and tend not to form an aqueous solution of which flow is prohibited under the conditions in which the solubilised biodegradation additive is prepared and used as described herein.

Examples of biodegradable organic compounds which are excluded or not preferred, because they may not be water-soluble, water-miscible (i.e. are very slightly soluble) and/or tend to form an aqueous solution of which flow is prohibited under the conditions in which the solubilised biodegradation additive is prepared and used as described herein, are gelatin, starch (gelatinised starch), some cyclic esters (e.g., E- caprolactone), and poly(p-dioxanone).

Chemoattractant

In preferred embodiments, the solubilised biodegradation additive also comprises a chemoattractant. A chemoattractant is a compound that attracts micro-organisms. Chemoattractants (or chemotaxis agents) are a well-known class of agents. They include, by way of example, amino acids, aromatic compounds, organic acids, phosphate, aromatic ketones (e.g., furanone), chlorinated compounds, and sugars.

In some embodiments of the present application, the selected chemoattractant is thermally stable at temperatures between 120°C to 130°C. Such chemoattractants that do not degrade within this temperature range and are able to promote chemotaxis in microorganisms after such heat treatment are preferred. For example, the decomposition temperature of most amino acids such as glycine, cysteine, asparagine and glutamine is at least 180°C or above, making these amino acids suitable options for the chemoattractant. Other suitable examples include collidine, xylose, aspartic acid, glutamic acid, alanine, methionine, serine, threonine. These and other suitable chemoattractants are able to attract species of rubber-degrading bacteria such as actinobacteria and pseudomonas. The types of elastomers that are made biodegradable in accordance with the present application have similar chemical bonds as compared to natural rubber, and so these bacteria are the types of bacteria that are desirably attracted by the subject chemoattractant.

Among the organic acids that may be selected as the chemoattractant, there may be mentioned the carboxylic acid and dicarboxylic acid classes. Suitable examples include acetic acid, lactic acid, glycolic acid, glutaric acid, citric acid, formic acid, tartaric acid, malic acid, oxalic acid and mixtures of one or more thereof.

Because the solubilised biodegradation additive is preferably water-based, then preferably the chemoattractant is water-soluble or water-miscible (i.e., able to form an aqueous solution) as described above in respect of the biodegradable organic compound. In preferred embodiments, the chemoattractant is at least slightly soluble and is preferably well soluble, more preferably freely soluble, as described above in respect of the biodegradable organic compound.

Specific examples of water-soluble or water-miscible chemoattractants include organic acids such as citric acid, tartaric acid, glutaric acid, lactic acid, malic acid, formic acid, acetic acid, oxalic acid and glycolic acid, disaccharides including lactose, xylose, organic amines such as collidine, and amino acids including glycine alanine, cysteine, threonine, serine, methionine, asparagine, glutamine, glutamic acid and aspartic acid. Preferred chemoattractants include citric acid, tartaric acid, glutaric acid, lactic acid, malic acid, formic acid, acetic acid, oxalic acid and glycolic acid, lactose, xylose, collidine, glycine alanine, cysteine, threonine, serine and methionine. These chemoattractants tend to be at least well soluble.

In preferred embodiments, the chemoattractant is a different compound from the biodegradable organic compound. For example, when the biodegradable organic compound is lactose, then preferably the chemoattractant is other than lactose, and so on. pH increasing agent

The pH increasing agent is intended to aid in the dissolution of the biodegradable organic compound for the production of the solubilised biodegradation additive. This applies mostly to embodiments where the solubilised biodegradation additive is waterbased. This agent may also provide anti-microbial activity during storage of the solubilised biodegradation additive. As pH increasing agents, the hydroxide pH increasing agents are preferred. Examples of alkali hydroxides that may be used as the pH increasing agent include potassium hydroxide, sodium hydroxide, aluminium hydroxide, ammonium hydroxide, calcium hydroxide and combinations thereof. Other soluble bases that form hydroxide ions may also be used.

Because the solubilised biodegradation additive is preferably water-based, then preferably the pH increasing agent is water-soluble or water-miscible (i.e., able to form an aqueous solution) as described above in respect of the biodegradable organic compound. In preferred embodiments, the pH increasing agent is at least well soluble, more preferably freely soluble, as described above in respect of the biodegradable organic compound. Preferred pH increasing agents include potassium hydroxide, sodium hydroxide and ammonium hydroxide. These tend to be very soluble.

The pH increasing agent can be added at dosages of within the range of 0.05 - 75% (based on the total amount of the solubilised biodegradation additive - including water). The amount may be between 0.1% and 60% by weight, or between 0.2% and 50% by weight based on the total amount of solubilised biodegradation additive.

Dispersant or surfactant

An optional component of the solubilised biodegradation additive is a dispersant or surfactant. The term “surfactant” refers to substances that lower the surface tension between two phases of matter. The term “dispersant” refers to the specific instance of improving the separation of particles in suspension in a liquid. The same substances may function as either a surfactant or dispersant, depending on the substances of their use, and therefore the expression “dispersant/surfactant” may be used herein to refer to substances of this type collectively. In the present instance, the dispersant/surfactant may stabilise the solution of the biodegradable organic compound, especially in water. Test work shown in the examples also demonstrates that the dispersant/surfactant may increase the pH range at which the biodegradable organic compound stays in solution without degradation or precipitation from the solution, i.e., may stabilise a solubilised biodegradation additive which is an aqueous solution. Where the pH range required for the solubilised biodegradation additive is within a range that permits long-term stability without a dispersant/surfactant, then this component may not be required in the solubilised biodegradation additive. However, utilising a dispersant/surfactant nevertheless may aid in maintaining long-term stability of the solubilised biodegradation additive, and permit a higher pH for the solubilised biodegradation additive to be maintained as an aqueous solution, which additionally may minimise any potential microbial growth in the solubilised biodegradation additive in liquid form. This is particularly useful in situations where pre-preparation of the solubilised biodegradation additive is sought for large-scale manufacturing operations. The pH control, combined with the addition of the dispersant/surfactant, may allow for an optimal balance of anti-microbial properties, stability (i.e., avoidance of degradation/precipitation), over time.

Examples of suitable dispersant/surfactants include salts of sulfonates and sulfates, (e.g., sodium dodecyl benzene sulfonate, sodium poly(naphthaleneformaldehyde) sulfonate, sodium lauryl sulfate or sodium lauryl ether sulfate); salts of carboxylic acid and salts of phosphates. The dispersant is preferably added at a dosage of 0.1 - 20% by weight, based on the total amount of the solubilised biodegradation additive. The amount may, for instance, be between 2% and 20% by weight, or between 8% and 20% by weight, or between 8% and 15% by weight.

Additional optional components

According to preferred embodiments, the solubilised biodegradation additive is formulated without microbes. Expressed another way, at the time of formulation, the solubilised biodegradation additive is free of microbes (i.e., detectably absent), or at least free of added microbes. Preferably, the input reagents are combined with water, but without any addition of a micro-organism or macro-organism. This contrasts to other formulations for biodegradation agents known in the art, where there is incorporation of a microbe, often in encapsulated or slow-release form, allowing for controlled release at a future point for commencement or acceleration of the biodegradation of the polymeric article. However, by avoiding microbes in the solubilised biodegradation additive assist so that the formulation can be prepared and maintained in a solubilised and stabilised state.

The solubilised biodegradation additive may be maintained in a solubilised and stabilised state for at least 3 months. Long-term stability is also able to be achieved, in which case the solubilised biodegradation additive may be maintained in a solubilised and stabilised state for at least 6 months. The solubilised biodegradation additive may be maintained in a solubilised and stabilised state for at least 9 months, at least 12 months, at least 15 months, at least 18 months, at least 24 months, at least 30 months or even at least 36 months. This may be by virtue of solubilising a biodegradable organic compound when forming the solubilised biodegradation additive, which may be assisted by the presence of a dispersant or surfactant, and/or being free of microbes (or free of added microbes), as described herein. In fact, stabilisation for a time period of at least 6 months, at least 9 months, at least 12 months, at least 15 months, at least 18 months, at least 24 months, at least 30 months or even at least 36 months, is possible for solubilised biodegradation additives described herein, which provides exceptional utility in large-scale elastomeric article manufacturing operations, and allows a manufacturer to avoid wastage and costs from reagent spoilage after being held beyond the acceptable shelf-life. An elastomeric article formed from the solubilised biodegradation additive may also be free of microbes (i.e., detectably absent), or at least free of added microbes, at the time of formation.

While in some embodiments microbes are not incorporated into the solubilised biodegradation additive, once a biodegradable elastomeric article is produced, microbial attack still occurs e.g., when the gloves are sent to waste. Microorganisms present in the waste environment cause biodegradation of the biodegradable organic compound (aided by the chemoattractant, when present), and catalyse the biodegradation of the elastomeric material of the elastomeric article.

The solubilised biodegradation additive is preferably free of any carrier resin, i.e. detectably absent. Carrier resins are utilised in some formulations to aid incorporation of the biodegradation agent into a polymer. Carrier resins are synthetic polymers (typically thermoplastic) which carry the biodegradation agent for melt-blending into a second thermoplastic polymer.

The solubilised biodegradation additive, and the elastomeric film-forming composition, is preferably substantially free of fillers, or free of fillers. Fillers are inorganic materials such as calcium carbonate. The term excludes inorganic pigments included in the elastomeric film-forming compositions at low levels (up to 1%) for pigmentation purposes. By “substantially free of fillers” means that the amount of substances that can function as fillers is less than 1% of the composition, preferably less than 0.5% or less than 0.2%. By “free of fillers” means that a filler is detectably absent.

The solubilised biodegradation additive, and the elastomeric film-forming composition, is preferably free of swelling agent(s), i.e., detectably absent. Such swelling agents produce a swelling effect especially when contacted with water over periods of time, to aid rupture of the structure of the article. Swelling agents may include cultured colloids, cyclodextrin and polylactic acid. Such agents are not suited to the technology described herein.

The elastomeric article may also be free of carrier resin, fillers and/or swelling agent(s) (i.e., detectably absent). This is achieved by using the solubilised biodegradation additive free of these components and avoiding the addition of such agents in the elastomeric film-forming composition. Optional additional components in the solubilised biodegradation additive may be selected from pigments, preservatives and/or rheology modifiers.

Amounts

The solubilised biodegradation additive may be formulated initially as a concentrated solution, and thereafter the solution, preferably an aqueous solution, may be diluted to a concentration (total solids content) that suits combination with the other components of the elastomeric film-forming composition.

The concentrated form of the solubilised biodegradation additive may have a total solids content (“TSC”) of about 20% to about 80%. The total solids content of the concentrated form of the solubilised biodegradation additive may be at least 30%, at least 40%, at least 50% or higher, but preferably not more than 80%.

In the state ready for use (i.e., ready for combining with the elastomer and the crosslinking agent(s)), the total solids content is typically in the range of 0.1% to 20%, preferably at least 0.5%, at least 1%, and preferably not more than 18%, 15%, 12% or 10% by weight. The amount may be within the range of 1% to 10% by weight, 1% to 9% by weight, 1% to 8% by weight, 1% to 7% by weight, or 1% to 6% by weight.

In the following passages, the amounts indicated for the components of the solubilised biodegradation additive relate to the formulation ready for combining with the elastomer and cross-linking agent(s). This may be referred to as the “ready to use state”. To determine the amounts of the components in the concentrated form of the solubilised biodegradation additive, the amounts may be multiplied by the relevant factor to reach a range of values suited to the concentrated state. The concentration factor in this case may be between a factor of 2 (e.g., if the TSC of the ready-to-use state is 10%, and the concentrated state is 20%) and 80 (e.g., the ready-to-use state TSC is 1% and the concentrated state has a TSC of 80%). The typical factor is between 5x and 20x. To dilute, the concentrated composition may be diluted by the same factor to achieve the ready-to-use state concentration (or total solids content).

The amount of the biodegradable organic compound in the solubilised biodegradation additive is suitably at least 0.05% w/w (based on the total weight of the solubilised biodegradation additive) to 10% w/w. The amount may be between 0.1% and 8%, or 0.1% and 5%, or 0.2% and 5%, for example. The biodegradable organic compound preferably constitutes at least 10% and up to 90% by weight of the non-solvent or non- water components (i.e., the solids) of the solubilised biodegradation additive. The amount is typically between 20% to 50% of the solids in the solubilised biodegradation additive.

The amount of the chemoattractant in the solubilised biodegradation additive is suitably between 0% w/w and 5% w/w (based on the total weight of the solubilised biodegradation additive). The amount may be between 0.05% and 4% w/w, or between 0.05% and 2% w/w, or between 0.1% and 2% w/w, for example. When present, the chemoattractant preferably constitutes at least 1% and up to 25% by weight of the non-solvent or non-water components (i.e., the solids) of the solubilised biodegradation additive. The amount is typically between 2% to 20% of the solids in the solubilised biodegradation additive.

The relative amount of the chemoattractant (when present) to biodegradable organic compound is preferably between 0.1 : 1 to 1 :1 , and most preferably between 0.1 :1 and 0.5:1 , by weight.

The amount of the pH increasing agent in the solubilised biodegradation additive is suitably at least 0.05% w/w (based on the total weight of the solubilised biodegradation additive) to 10% w/w. The amount may be between 0.1% and 10%, or between 0.2% and 8%, or between 0.5% and 5%, for example. The pH increasing agent preferably constitutes at least 20% and up to 90% by weight of the non-solvent or non-water components (i.e., the solids) of the solubilised biodegradation additive. The amount is typically between 20% to 70% of the solids in the solubilised biodegradation additive.

The pH of the solubilised biodegradation agent is preferably between 8.0 and 14.0, or between 8.0 to 13.0. In some embodiments, the pH is between 11 .0 and 13.0.

The amount of the dispersant/surfactant in the solubilised biodegradation additive is suitably between 0% w/w and 5% w/w (based on the total weight of the solubilised biodegradation additive). The amount may be between 0.05% and 4% w/w, or between 0.05% and 2% w/w, or between 0.1% and 2% w/w, for example. When present, the dispersant/surfactant preferably constitutes at least 0.1% and up to 25% by weight of the non-solvent or non-water components (i.e., the solids) of the solubilised biodegradation additive. The amount is typically between 0.1% to 20% of the solids in the solubilised biodegradation additive. Combining with Elastomer

The solubilised biodegradation additive is combined with elastomer and cross-linking agent(s), and other optional components of the formulation for the elastomeric filmforming composition.

The amount of solubilised biodegradation additive included in the formulation for the elastomeric film-forming composition may be between 0.1 phr and 10 phr, preferably between 0.1 phr and 5.0 phr. The amount may be greater than 0.1 phr, and not more than 4.0, 3.5 or 3.0 phr (each range considered separately). The amount is preferably at least 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 .0 phr, with an upper limit of 10 phr or 5 phr. Any lower and upper amount can be combined to form a range. For example, the amount may be between 0.2 phr and 10 phr, 0.5 phr and 5 phr, and so on.

The components of the elastomeric film-forming composition are described in further detail below. Thereafter, details of the biodegradable elastomeric articles produced from the elastomeric film-forming composition are described.

Elastomeric film-forming composition

In the following section the components of the elastomeric film-forming composition used to produce the or each layer of an elastomeric film are described. As noted above, for multi-layered articles, one, multiple or all layers of an article may be produced from an - elastomeric film-forming composition containing the solubilised biodegradation additive. The following description applies to any of the elastomeric film layers of the elastomeric article, with the proviso that one layer is formed with the solubilised biodegradation additive. In preferred embodiments, at least 50% of the elastomeric film layers of the elastomeric article are biodegradation additive-containing elastomeric film layers (e.g., at least 1 in 2 layers of a two-layered film article), preferably at least 66% of the elastomeric film layers are biodegradation additivecontaining elastomeric film layers (e.g., at least 2 in 3 layers of a three-layered film article), and most preferably all elastomeric film layers are biodegradation additivecontaining elastomeric film layers (e.g., all layers in a single-layer film article, a two- layer film article or a three-layer film article).

The elastomeric film-forming composition from which the elastomeric film is made comprises the elastomer and one or more cross-linking agents in a liquid medium. The liquid medium is typically, and is preferably, water. Each component used to prepare the elastomeric film-forming composition may be incorporated into the formulation as a neat compound, or as a solution or suspension in water. For example, the pigment may be added in solid form (TSC 100%), and the elastomer may be added as an emulsion in water (e.g., with a total solids content of around 40% - 50%). The total solids content of the overall formulation will be based on the contribution provided by each component to the overall elastomeric film-forming composition. The overall formulation for the elastomeric film-forming composition may have a total solids content of from 5% to 60% by weight of the composition. The total solids content can vary within this range, and in some embodiments the total solids content is about 5% to 50%, about 10% to 50%, or about 20% to 50%.

It is also common in the art to use the expression “latex” or “rubber” to refer to any elastomer in a general sense, even if the polymer in the latex, or the elastomer used, is not natural rubber specifically. Accordingly, particularly in the examples which follow, it should be understood that if these terms are used, they do not necessarily refer to natural rubber latex or natural rubber specifically, and they are used as short-hand to refer to the identified elastomer of the dipping composition.

Elastomers

Elastomer-forming polymers include natural rubber and synthetic elastomer-forming polymers, which can be cross-linked to produce elastomeric films. The polymer may be a single polymer or a combination of two or more polymers. The polymer may be a homopolymer or a copolymer, or a blend of polymers/copolymers.

The elastomer-forming polymers may be selected from rubber (natural or synthetic), nitrile rubber, polyurethane, polyisoprene, polychloroprene, polyvinyl chloride, polybutadiene, halogenated polybutadiene, polyacrylonitrile butadiene rubber, styrenebutadiene rubber, fluoroelastomers, butyl rubber, acrylic polymers (including acrylic diene block copolymers), and copolymers of these with other polymers/monomers (random copolymers, block copolymers or otherwise). In each instance, the elastomer may be carboxylated or non-carboxylated (e.g., the polychloroprene may be carboxylated polychloroprene or non-carboxylated polychloroprene). Modified forms of these elastomers or copolymer thereof (e.g., polymers containing additional substituents such as carboxylate, sulfonate, halide or other substituents) are also encompassed.

The elastomers are preferably selected from natural or synthetic rubber (i.e., polyisoprene), nitrile rubber (i.e., polyacrylonitrile butadiene) and polychloroprene.

These elastomers may be carboxylated or non-carboxylated. Blends or co-polymers of these elastomers may also be used.

One notable example of a synthetic elastomer-forming polymer is nitrile rubber - also known as polyacrylonitrile butadiene. This may be carboxylated or non-carboxylated. This may be provided as a mixture of carboxylated nitrile latex and nitrile butadiene rubber. Another example of a suitable elastomer-forming polymer is self-crosslinking nitrile butadiene latex.

Carboxylated refers to the presence of carboxylate (carboxylic acid or ester) groups on the polymer chain. Carboxylation may be achieved by forming the polymer with a monomer containing carboxylate groups, or through grafting carboxylate groups to a polymer. As examples of suitable carboxylated polymers, reference is made to PCT/AU2014/000726 and PCT/AU2014/000727, the entirety of each being incorporated into this specification by reference.

In the art of the present invention, it is common to refer to the amount of the elastomer as being 100 phr (per hundred parts “rubber”), and for the relative amounts of the remaining components of the elastomeric composition to be calculated as a number of parts compared to the 100 phr of the elastomer, by weight. Thus, for an amount of cross-linking agent that is 1/100th that of the elastomer in the composition by weight, the amount of cross-linking agent is referred to as 1 .0 phr.

In preferred embodiments, at least 99% by weight of the polymeric components of the elastomeric article are elastomeric. Expressed another way, the elastomeric article is substantially free (i.e., at least 99% by weight free) of any non-elastomeric components, and does not comprise a blend of elastomeric and non-elastomeric polymers, such as thermoplastic resins.

More preferably, the biodegradable elastomeric article is free of non-elastomeric polymers other than any non-elastomeric polymers that may be providing biodegradability to the composition. Accordingly, the elastomeric article is preferably free of any non-elastomeric thermoplastic resins. It will be understood that the elastomeric article may comprise biodegradable organic compound that is in polymeric form, and that such biodegradable components are not considered to constitute “thermoplastic resins”. Cross-linking Agents

The elastomeric film-forming composition comprises one or more cross-linking agents. Elastomer-forming polymers can be cross-linked with one or more cross-linking agents to produce an elastomeric film. Various types of cross-linking agents can be used. Cross-linking agent classes include ionic cross-linking agents and covalent crosslinking agents. The cross-linking agent or agents used in the production of an elastomeric film may be selected from ionic cross-linking agents, covalent cross-linking agents, and combinations thereof. The selection will depend on various factors including the properties of the film desired and the choice of elastomer.

Ionic cross-linking agents include metal oxide cross linking agents (such as zinc oxide and magnesium oxide), peroxides (such as 1 ,1 -di(t-butylperoxy)-3,3,5- trimethylcyclohexane, which can be purchased under the trade name Trigonox 29-40B- pd), trivalent metal-based cross-linking agents, such as sodium aluminate. The trivalent metal cross-linking agent may be solubilized to produce a negatively charged multivalent metal complex ions.

Covalent cross-linking agents include organic cross-linking agents, sulphur and/or sulphur donors, and combinations thereof. The elastomeric film-forming composition may contain sulphur, or it may be sulphur-free.

Sulphur may be added in the form of elemental sulphur. Sulphur donors are another way of providing sulphur cross-linking. Sulphur donors release sulphur, or act with sulphur-containing compounds, to accelerate sulphur-based covalent cross-linking of the elastomer-forming polymer. These sulphur donors may also be referred to as accelerators. Examples of suitable sulphur donors include the carbamates such as thiocarbamates (e.g., zinc dibutyl dithiocarbamate (ZDBC), Zinc diethyl dithiocarbamate (ZDEC); Zinc dimethyl dithiocarbamate (ZDMC); thiurams (e.g., tetraethylthiuram disulfide (TETD), Tetramethylthiuram disulphide (TMTD)); Dipentamethylene thiuram tetrasulfide (DPTT); Dipentamethylene thiuram hexasulfide (DPTH); Dipentamethylene thiuram hexasulfide; thiourea (Ethyl thiourea (ETU) and diphenylthiourea (DPTU); thiazoles (e.g., Mercapto Benzothiazoles (MBT), Mercapto Benzothiozole disulphide (MBTS), zinc 2-mercaptobenzothiazole (ZMBT)); guanidines (e.g., Diphenylguanidine (DPG)) and aldehyde/amine-based sulphur donors (e.g., hexamethylenetetramine). Other examples are well known in the art and can be obtained from various publicly available sources. In broad terms, any amount of cross-linker may be used, as required for the final article properties. Thus, the total amount of cross-linking agents in the composition may be between 0.01 phr and 14 phr. The total cross-linking agent amount may be within one of the following ranges: 0.01 phr - 8 phr, 0.1 phr - 6 phr, 0.1 phr - 5 phr, or 0.01 phr - 1.0 phr.

The amount of ionic cross-linking agent may be between 0.0 phr - 4.0 phr, such as 0.01 phr - 4.0 phr. The amount is preferably lower still, at 0.01 phr - 3.0 phr, or 0.01 phr - 2.0 phr, 0.01 phr - 1 .0 phr or 0.01 phr - 0.5 phr.

The amount of sulphur may be between 0.0 phr - 5.5 phr. The amount may be lower still, at 0.0 phr - 3.5 phr, such as 0.01 phr - 3.0 phr, 0.01 phr - 2.0 phr, 0.01 phr - 1 .5 phr, 0.01 phr - 1 .0 phr or 0.01 phr - 0.5 phr.

The amount of sulphur donor (e.g., accelerator) may be between 0.0 phr - 2.0 phr, such as between 0.1 phr - 1 .5 phr, 0.1 phr - 1 .0 phr, 0.2 phr - 1 .0 phr, 0.3 phr - 2.0 phr, 0.3 phr - 1 .5 phr or 0.2 phr - 0.6 phr.

The cross-linking agent may in some embodiments comprise an ionic cross-linking agent, sulphur and an accelerator. The cross-linking agent may in some embodiments comprise zinc oxide, an ionic cross-linking agent other than zinc oxide, sulphur and accelerator.

Other components of the elastomeric film-forming composition

The elastomeric film may further comprise one or more of the following conventional components of an elastomeric film-forming composition: plasticizers, anti-oxidants, anti-ozonants, stabilisers such as pH stabilisers, pH adjustors (e.g., agents for increasing the pH, such as potassium hydroxide, ammonia, sodium hydroxide, or mixtures thereof), surfactants, emulsifiers, antioxidants, polymerisation initiators, pigments, opacifying agents, colourising agents, rubber reoderants/deoderants, wetting agents, defoamers and sensitisers. While fillers may also be included, the composition is preferably substantially free of fillers, or free of fillers. These agents, and the amounts and examples thereof, are as described in PCT/AU2014/000726 and PCT/AU2016/050308; the entirety of each is incorporated by reference.

Optional antimicrobial agent in the elastomeric film-forming composition

In some embodiments, the elastomeric film-forming composition from which a layer of the elastomeric film is made contains one or more antimicrobial agents. In these embodiments, another layer of the film will preferably be a barrier film layer, which is free of the antimicrobial agent (and free of the skin-protective agent). In embodiments where the elastomeric article is a dipped article, this is typically the first film layer, which ends up on the outwardly-facing surface of the article when the article is inverted by stripping from the former. The barrier layer may be formed with the solubilised biodegradation additive. For example, when the elastomeric article is a dipped article and the first film layer comprises an antimicrobial agent, the solubilised biodegradation additive may be included in the second dipped layer which may be a barrier layer, and which may end up on the inwardly-facing surface of the article when the article is inverted by stripping from the former.

The antimicrobial agent in the first elastomeric film-forming composition may be a pyrithione antimicrobial agent.

The antimicrobial agent may be present in the elastomeric film-forming composition at a concentration of from about 0.01 phr to 20 phr, when incorporated through this technique. In some embodiments the maximum amount is 15, 10, 5 or 3 phr. In some embodiments, the minimum amount (when present) is 0.01 , 0.05, 0.1 , 0.5, 1 .0 or 2 phr. Any maximum and minimum cam be combined to form a range. Suitable ranges include 0.05 phr to 15 phr, 0.1 phr to 10 phr, 0.5 phr to 5 phr, and 2 phr to 3 phr.

In other embodiments, the elastomeric film layer, or a second or further elastomeric film layer, may comprise any other desirable components. Examples include colouring agents, such as black colour layer, detectable particles, such as metal detector- detectable particles, one example being iron oxide particles.

Formulation for elastomeric film-forming compositions of embodiments of the invention

In some embodiments, the elastomeric composition used to form a film layer of the elastomeric article comprises:

(a) The solubilised biodegradation additive as described above;

(b) A dispersion of a film-forming elastomer (such as nitrile, natural rubber, selfcrosslinking nitrile butadiene latex, polychloroprene, polyisoprene, polyurethane, polyacrylic, polyvinylpyrrolidone, polystyrene butadiene rubber, fluoroelastomer, butyl rubber, polyvinyl chloride, polybutadiene, polysiloxane, or mixtures thereof);

(c) One or more crosslinking agents (such as sulphur, sulphur donor, metal oxide, ionic crosslinking agent and the like); (d) Optionally an accelerator (such as dithiocarbamate, thiuram, mercapto and the like); and

(e) Optionally one or more additional components selected from a surfactant, a pH adjusting agent, anti-oxidant, anti-ozonant, wetting agent, emulsifier, defoamer, stabilizer, rubber deodorant, colour pigment, opacifier and the like.

In preferred embodiments, the dispersion of a film-forming elastomer is a dispersion in water. In other words the dispersion of a film-forming elastomer is a water-based dispersion of a film-forming elastomer.

In some embodiments, the elastomeric composition is accelerator-free. In some embodiments, the crosslinking agent in the elastomeric composition is sulphur-free.

Preparation of the elastomeric article

A former in the shape of the desired article is dipped into the elastomeric film-forming composition and then dried and/or cured. Curing is used in a general sense to refer to the stage during which cross-linking is performed. Such curing conditions are as known in the art.

The articles of the present application are dipped elastomeric articles, the elastomeric article is suitably prepared by a dipping process.

In brief, in one embodiment of the invention, the method for the production of the elastomeric article may comprise:

- dipping the former (i.e., mould) into a coagulant composition,

- dipping the coagulant-dipped mould into the first elastomeric film-forming composition for producing a first layer of elastomeric film on the mould;

- optionally dipping the mould into additional elastomeric film-forming composition(s) prior to or following the dipping into the first elastomeric film-forming composition (either of the same composition as the first elastomeric film-forming composition, or a different composition); drying and/or curing the layer of elastomeric film-forming composition on the former to produce the elastomeric article; and

Removing the elastomeric article from the former.

Whilst the above series of steps outlines one technique for producing the elastomeric articles, variations to this process may be made as described in detail below. It should be understood that additional variations may be made to this process as known or described in the art. The steps in the manufacture of an elastomeric film or article may be as generally described in PCT/AU2014/000726 and PCT/AU2014/000727, which are incorporated by reference.

Optional step (a) Dipping the former into a coagulant containing metal ions in solution

Dipping the former into a coagulant composition is an optional step in the process for the production of dipped biodegradable elastomeric articles. Charged ions in the coagulant form a charged ion coating on the former that can assist in controlling the amount of elastomeric film-forming composition that will subsequently remain on the surface of the former after dipping into the film-forming composition, through charge interactions.

The coagulant comprises charged ions, such as metal salt ions. Examples of such metal salt ions are sodium, calcium, magnesium, barium, zinc, and aluminium. Preferred metals are the multivalent metals. The counter ions may be halides (such as chloride), nitrate, acetate or sulphate, amongst others. In the case of calcium ioncontaining coagulants, the calcium ions can be provided as a solution of calcium nitrate or calcium chloride. Other optional components of the coagulant may include wetting agents (such as fatty alcohol ethoxide or other suitable surfactants), anti-tack agents, anti-foaming agents and/or mould release agents (such as silicon emulsions), polymer release agents and metallic stearates (such as zinc, calcium and potassium stearates).

The concentration of metal salt, as the ion source, in the coagulant can broadly be in the range of 0.0 - 50% by weight of the coagulant composition, depending on the desired thickness of the elastomeric film layers and the number of layers to be applied (i.e., one layer or two or more layers). In the case of thinner layers, the metal salt concentration is suitably in the range of 0.0 - 20%, 0.0 - 15%, 0.0 - 12%, 1.5 - 20%, 1.5 - 15%, 1.0 - 10%, 1.5 - 10%, 4 -10%, 5 - 10%, 5 - 35%, 10 - 30%, 7 - 40%, 8 - 50% and 5 - 45%. The amounts of other optional components such as wetness and anti-tack agents are dependent on the properties desired through the use of these agents and will vary accordingly.

Optional step (b) Drying or partially drying the coagulant-dipped former

If the former is dipped into a coagulant, following this step the former is dried or partially dried. Step (i) Dipping the former into a first elastomeric film-forming composition to produce a layer of elastomeric film-forming composition on the mould

The former is dipped into a composition for producing an elastomeric film, embodiments of which have been described in detail above.

The former is in the dipping tank for an amount of time (a dwell time) to ensure the former is evenly coated, but not so long as to develop a thicker coating than necessary.

The temperature of the composition into which the former is dipped is generally within the range of 10°C to 60°C. The temperature may be modified or controlled to be within a narrower temperature range if the first film-forming composition contains any components that are sensitive to heat.

If a single film-layer article is produced, the next step performed is step (v).

Step (ii) Drying or partially drying the first layer of elastomeric film-forming composition on the former

Where a second (and optionally further) film layer is being applied, the first layer is dried or partially dried prior the next stage of dipping. Conventional drying conditions as is known in the art is used in performing this step, such as those described in the PCT publications referred to previously.

Step (Hi) Optionally dipping the former coated with the dried or partially dried first layer of elastomeric film-forming composition into a second elastomeric film-forming composition to produce a second layer of elastomeric film-forming composition on the former

This step is optional and is present when multilayer film articles are produced. The temperature, dwell time and total solids content for the elastomeric film-forming composition used to produce the second layer of the glove (i.e., the second elastomeric film-forming composition) may be the same as for the first dip, or they may be different. The second elastomeric film-forming composition into which the former is dipped may be the same as that for the first dip, or it may be different. That is, the composition of the first dipping step may contain the solubilised biodegradation additive, or the composition of the second dipping step may contain the solubilised biodegradation additive, or both compositions may contain the solubilised biodegradation additive. Step (iv) Optionally repeating the drying or partial drying step (ii) and the further dipping step (Hi)

This step is optional and is present when multilayer film articles are produced. The number of film layers may be 2, 3 or more in multilayer film articles. In each subsequent dipping stage, the choice of film-forming composition will be selected to produce the required layered structure desired, and the selected biodegradation performance properties (based on the presence or absence of the biodegradation agent).

Step (v) Optional additional steps prior to curing

Further steps can be taken to fine-tune the manufacture of the elastomeric film or article. The details of some optional steps that may be performed prior to curing are as described in the PCT publications referred to above. In brief, the film or article can be pre-leached to remove extractable components, there may be a coating material applied before/after beading/cuffing is optionally performed. In some embodiments, a leaching step (described as pre-leaching) is performed following the elastomeric film composition dipping steps, and prior to curing. A leaching step can be useful to remove or wash away excess chemical residues. Preferably, the conditions of any pre-leaching step are suitable to avoid leaching away of the solubilised biodegradation additive.

Step (vi) Drying/curing the layered elastomeric film on the former

A drying/curing step is performed prior to stripping of the articles from the former. This step usually involves curing conditions to cure the elastomeric film. The curing step is well known in the art, and suitable conditions for this step are as described in the PCT publications referred to above.

Step (vii) Post-curing steps

After curing but prior to stripping of the article from the former, additional steps can be performed. Such optional steps may include cooling (former cooling in water), chlorination (which may be standard concentration or mild chlorination), post-leaching, applying a coating material, and additional drying steps.

Step (viii) Stripping

The film or article is stripped from the former at the conclusion of the formation process. Step (ix) Post-stripping steps

The elastomeric articles, such as gloves, may be packaged to protect and/or preserve the articles until the package is opened to allow use of the gloves. The packaging may be in pairs, or the packaging may be of larger numbers of articles together. The packaging may be a sealed package that prevents contact with the external environment of the package. The package may be a vacuum pack.

Elastomeric Articles

Examples of elastomeric articles that benefit from biodegradability include wearable articles, including gloves (encompassing disposable gloves, surgical gloves, examination gloves, industrial gloves, laboratory gloves, irradiation gloves, clean room gloves for electronic industries, gloves for food contact and food processing and biotechnical application, household gloves, supported gloves and so forth), finger cots, footwear (such as foot covering, socks, booties), medical dressings and the like. The articles are suitably disposable elastomeric articles - being of light weight and low cost, suitable for disposable after a period of use. The articles may be thin film articles. The articles are produced by dipping processes and are dipped articles. The former used for the dipping process is shaped in accordance with the type of article - hand-shaped for a glove, finger-shaped for finger cot, or foot-shaped for footwear.

The thickness of the elastomeric film (including any coating applied to the article) can, for example, be in the range 0.01 mm - 3.0 mm, such as 0.01 mm - 2.0 mm, 0.01 mm - 1 .0 mm, 0.01 mm - 0.3 mm, 0.02 mm - 0.2 mm, 0.01 mm - 0.1 mm, 0.01 mm - 0.05 mm, 0.05 mm - 0.10 mm, 0.03 mm - 0.08 mm, or 0.05 mm - 0.08 mm (for thin or disposable gloves and articles), and 0.2 mm - 3.0 mm for thick gloves and articles. The thickness is suitably measured as an “average thickness” for the article. In the case of gloves, the thickness is measured using an average of the thickness measurements taken at the cuff, palm and finger locations, according to the relevant standard, that is, ASTM D6319-19 generally, or ASTM D3578-19 (for natural rubber examination gloves) or ASTM D6977-19 (for polychloroprene examination gloves).

The finger thickness is measured 13 mm +/- 3mm from the fingertip; the palm thickness is measured at the centre of the palm, and the cuff thickness is measured at 25mm +/- 5mm from the cuff edge. Thickness measurements for any elastomeric articles are taken in accordance with the procedure specified in ASTM D3767-03 (Reapproved 2020). The elastomeric articles as described herein substantially retain the desirable elastomeric properties of the underlying elastomeric films, in spite of the inclusion of the solubilised biodegradation additive. It was anticipated that the presence of the solubilised biodegradation additive could have an adverse impact on the physical properties (i.e., typical measured properties, as distinct from biodegradability performance). However, the elastomeric articles were found to have an excellent balance of physical properties, together with biodegradation properties following disposal.

The modulus at 500% of the articles of some embodiments is up to 50 MPa. The modulus is typically less than 50 MPa. This modulus range allows for gloves with a thickness of above 1 .0 mm and up to 3.0 mm. For example, the modulus at 500% may be up to 30.0 MPa, 20.0 MPa, or between 5.0 MPa and 20.0 MPa, or up to 18.0 MPa, or up to 15.0 MPa, or up to 11 .0 MPa. The modulus at 500% for gloves with a thickness of less than 1 mm is preferably not more than 40 MPa, not more than 20.0 MPa or not more than 15.0 MPa, or between 10.0 MPa and 15.0 MPa, or between 7.0 MPa and 10.0 MPa, or between 2.0 MPa and 10.0 MPa, or between 2.0 MPa and 7.0 MPa, or up to 8.0 MPa, or up to 6.0 MPa. The modulus at 500% for gloves with a thickness of less than 0.3 mm is preferably not more than 20 MPa, not more than 10.0 MPa, not more than 8.0 MPa, or not more than 6.0 MPa, or between 1 .0 MPa and 20.0 MPa, or between 1 .0 MPa and 10.0 Mpa, or between 1 .0 MPa and 8.0 MPa or between 1 .0 MPa and 6 MPa.

The modulus at 300% elongation of the articles of some embodiments is less than 25 MPa, or less than 10 MPa. For example, the modulus may be between 1 .0 MPa and 10.0 MPa, between 1 .0 MPa and 5.0 MPa, or between 1 .0 MPa to 4.0 MPa. A modulus at 300% elongation that is as high as 25 MPa allows for higher thickness gloves - with a thickness of at least about 1 mm and up to 3 mm.

It is noted that the modulus values (at 300% and 500% elongation) are based on unaged films. The ranges indicated may also apply to aged films.

The modulus at 100% elongation of the articles may be up to about 15 MPa. This value encompasses both low thickness gloves (about 1 mm thickness or less) and higher thickness gloves - 1 mm - 3 mm in thickness. The modulus at 100% elongation of the articles of some embodiments, before aging, is up to 2.00 MPa, or up to 1.90 MPa. The modulus at 100% elongation of the articles of some embodiments, after aging, is less than 2.00 MPa, or less than 1 .95 MPa. In some embodiments, the elastomeric article has a tensile strength (unaged) of at least 8 MPa (e.g., from 8 MPa to 50 MPa, at least 14 MPa, or from 14 MPa to 35 MPa).

When comparing the tensile strength of the article of the present application against that for the same article without the solubilised biodegradation additive, it is desirable for there to be minimal change. In some embodiments, the tensile strength does not vary from that of a comparative article without the solubilised biodegradation additive by more than 50%, 40%, 30%, 20% or 15%.

In some embodiments, the elastomeric article has an elongation to break of at least 500% (e.g., between 500% and 1000%, from 600% to 1000%, or from 700% to 1000%).

The elongation at break of the products of the present application may be slightly lower than that of a comparison or control product that is free of the solubilised biodegradation additive. The elongation at break is preferably not more than 20% less than that of a control product that is free of the solubilised biodegradation additive, preferably not more than 15% less, or not more than 10% less, or not more than 8% less, or not more than 6% less. This applies to the before-aging values. This also applies to the after-aging values. As shown in the examples, in some embodiments, the elongation at break is 666%, compared to 690% for the control (same formulation and thickness, but without the additive), as compared to a prior art sample with an elongation at break of 626%. The elongation at break may in some instances be higher than that of the comparison product, potentially up to 10, 15 or 20% higher.

The elastomeric article may have one, two or all three of the modulus, tensile strength, and elongation at break values within the ranges indicated above.

The calculations of weight, thickness, modulus, tensile strength and elongation may be based on a sample of at least 10 articles (e.g., gloves or finger cots).

The elastomeric film may be a self-supported or unsupported film. A self-supported or unsupported film is a film that exists without other structural components or layers that the film is adhered to or attached to.

The biodegradable elastomeric articles as described herein may degrade under aerobic or anaerobic conditions. In preferred embodiments, elastomeric articles made with a solubilised biodegradation additive as described herein degrade at least 5%, or at least 10%, or at least 15%, or at least 20% when tested in accordance with the procedure specified in ASTM D5526. The solubilised biodegradation additive as described herein may be characterizable as nontoxic to plants or plant parts when tested in accordance with the procedures of ASTM E1963. By the phrase “plant parts” as used herein is meant a structure, such as a leaf, stem, flower, seed or root of a plant. In preferred embodiments, the plant part is a seed. In preferred embodiments, the plant is aTriticum species plant or a Brassica species plant, preferably Triticum aestivum or Brassica juncea.

The solubilised biodegradation additive is characterizable as nontoxic to plants or plant parts when tested in accordance with the procedures of ASTM E1963 when it presents with one or more of the following:

- A germination rate of at least 80%, preferably 85%, preferably 90%, of germination rate of a positive control;

- A shoot weight of at least 80%, preferably 85%, preferably 90%, of shoot weight of a positive control;

- A shoot length of at least 50%, preferably 55%, preferably 60%, of shoot length of a positive control; and

- A root length of at least 50%, preferably 60%, preferably 65%, of root length of a positive control.

The positive control of ASTM E1963 is a watering solution of boric acid at desired concentration, as used herein the concentration being at least 40 mg/kg.

The solubilised biodegradation additive may be characterizable as nontoxic to plants or plant parts when tested in accordance with the procedures of ASTM E1963 at a soil concentration of up to 10 mg/kg, or up to 100 mg/kg, or up to 1 ,000 mg/kg, or up to 5,000 mg/kg, or up to 10,000 mg/kg.

Definitions

As used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a biodegradable organic compound" includes one, two or more biodegradable organic compounds.

In the claims and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e., to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

EXAMPLES

The invention will now be described in further detail with reference to the following nonlimiting examples produced in accordance with embodiments of the invention.

Testinq of qlove

Glove are tested to determine the following properties:

• Biodegradation performance - using the Biomethane Potential Test (BMP)

Modulus at 100%, 300% and/or 500% elongation;

Tensile strength (MPa/psi) (1 MPa = 145 psi)

Elongation %; and

Force at break (N).

Tensile strength, stress at 100%, 300% and/or 500% modulus and elongation to break are measured by testing procedures conducted in accordance with ASTM D 412-16 (2021 version), based on the sample size set by the standard for gloves. The gloves are also tested for force at break measured in accordance with EN 455. The standards are readily available. These tests can be applied to multilayer films and gloves (such as examination gloves for medical applications). Tensile strength and modulus are measured in units of MPa, force at break in N, and the elongation (or elongation at break) in %.

of solubilised biodegradation additive for compounding

1. Example 1: Solubilised biodegradation additive comprising biodegradable organic compound and pH increasing agent

1.1. Method

1.1.1. The additives were prepared by stirring the biodegradable organic compound with 3% KOH as the pH increasing agent until the additive had dissolved completely.

1.1.2. All chemicals were then covered and left at room temperature for more than a week. 1.2. Results & Discussion

Table 1 : Sample type and properties

Table 2: pH data of all chemicals

*pH values taken on the 7^th day. a. It was found that additives with increasing amount of KOH were easily dispersed and dissolved in water. b. It was found that Additives B and C had remained stable throughout the week. It is noted that the pH range between 5.7 - 10 shows stability within 1 week. c. The preparation of low-pH aqueous solution such as A displayed a different observation compared to the high-pH aqueous solutions which is the presence of a mold-like substance on Day 8. It is likely to happen due to the presence of a chemotaxis agent in the biodegradation additive which attracts microorganisms. d. Aqueous solutions with higher pH such as Additives D and E were found to have some sediment. This observation indicated a sort of instability which is not present in low-range pH, therefore it is believed to have been instigated by the addition of KOH.

1 .3. Conclusion

1.3.1. Preparation of solubilised biodegradation additive (without dispersant) requires a pH value of around 5.7 - 10, where a value with acceptable deviations and suitable pH for incorporation into latex composition would be 8 - 9. Example 2: Solubilised biodegradation additive preparation with dispersant

2.1. Introduction

The previous experiment provided a conclusion that the biodegradation additive can be dispersed and dissolved in alkaline aqueous solution, and a stable solubilised additive is achieved within a week. Biodegradable aqueous solutions with higher pH tend to have sediment formations within first week of preparation, and is deemed unstable. To increase the range of pH in which the solubilised biodegradation additive can be prepared, the study below was carried out.

2.2. Objective

To evaluate stability of biodegradation additive at high pH range with addition of dispersant.

2.3. Method

2.3.1 . All samples were prepared according to Table 3.

2.3.2. All chemicals were stirred, covered and left for more than a week. Table 3: Sample details and properties

2.4 Results & Discussion

Table 4: pH data and observations

It was found that Additive D2 had remained stable throughout the week despite the high level of pH. It appears that the brown sediments require a sort of dispersant to prevent their formation.

2.5. Conclusion

2.5.1 . Preparation of biodegradation additive with anionic dispersant only (acidic pH) resulted in instability within one week.

2.5.2. Preparation of biodegradation additive (alkaline pH) resulted in instability within one week.

2.5.3. Preparation of biodegradation additive with anionic dispersant (alkaline pH) resulted in a stable mixture after 1 week.

3. Comparative Example 3: Attempted re-dissolution of precipitate from solubilised biodegradation additive

3.1. Introduction

E and F (high pH levels) had brown sediment appearances on Day 3 onwards. In this study, dispersant was added at Day 15 to observe whether the sediments can be re-dispersed into the mixture.

3.2. Objective

To evaluate stability and appearance of sedimentation after adding dispersant in high-pH biodegradation additive preparation.

3.3. Method

3.3.1 . Anionic dispersant was added into Additives E and F at 2 %wt and stirred until all sediments were dispersed.

3.3.2. All chemicals were covered and left to stand.

Table 5: Sample type and properties:

3.3 Results

Table 6: Observations following addition of anionic sulfonate dispersant at day 15

3.4 Conclusion

3.4.1 Sediments cannot be re-dispersed after its appearance in the biodegradation additive with high pH levels.

4 Example 4 - Preparation of biodegradation additive with different dispersants

4.1 Objective

To prepare biodegradation additive using different amounts of anionic dispersant. 4.2 Method

4.2.1 All samples were prepared according to Table 7.

4.2.2 All chemicals were stirred, covered and left for two weeks.

Table 7:

Formulation I - total solids breakdown:

4.3 Results and Discussion

Table 8: Observations after 1 week or 2 weeks:

Formulations H and I were both found to be extremely stable, with no changes after two weeks. Formulations J and K were also found to be stable, with no changes after 7 days. A batch of the formulation of Sample I has been kept in storage for 3 years, and has remained stable over this time period, based on visual assessment. This further demonstrates the excellent stability of the formulations over long periods of time. Given this stability information, stability of formulations for time periods of at least 3 months, including long-term stability of at least 6 months, including at least 9 months, at least 12 months, at least 15 months, at least 18 months, at least 24 months, at least 30 months or at least 36 months are shown to be achievable.

4.4 Conclusion

The use of a lower amount of the same anionic surfactant in the formulation (I, compared to H) was equally as stable. The use of a lower content of the anionic sulfonate surfactant was selected for use in the production of gloves in the following example.

Examples of preparation of elastomeric articles

5 Example 5. Glove preparation using solubilised biodegradation additive

5.1 Objective

To evaluate the physical performance of gloves containing the solubilised biodegradation additive.

5.2 Method

5.2.1 All formulations were prepared according to Table 9, W and 11.

5.2.2 3 mm thick glove samples were produced by dipping a former into the formulation to be tested, drying/curing the film composition, and removing from the former. Physical properties of the samples were tested at 22°C.

Table 9: Nitrile butadiene rubber latex formulation without solubilised biodegradation additive - Formulation 1 :

Table 10: Nitrile butadiene rubber latex formulation with solubilised biodegradation additive - Formulation 2 (same cross-linking agent combination and amounts as Formulation 1 ):

Table 11 : Nitrile butadiene rubber latex formulation with solubilized biodegradation additive - Formulation 3 (higher cross-linking agent amounts as compared to Formulation 2):

5.3 Results

Table 12: Physical properties of gloves:

a. It was observed that preparation of solubilized biodegradation additive has an impact on the tensile strength of the gloves, compared to the control sample of formulation 1 . However, by adjustment of the cross-linking agent amounts (formulation 3), this was counteracted. b. As for the incorporation of the biodegradation additive, the formulation required additional amount of anionic surfactant which may be detrimental to the properties of the gloves as well. However, the strength of the gloves can be improved by manipulating the amounts of ionic cross-linking agent and sulphur used in the preparation of the gloves.

5.4 Conclusion

5.4.1 Addition of the solubilised biodegradation additive can have an impact on the physical properties of the gloves.

5.4.2 This can be counteracted by the slight adjustment in the cross-linking agent amounts.

6 Example 6. Glove preparation using solubilised biodegradation additive

6.1 Objective

To evaluate the physical performance of gloves containing solubilised biodegradation additives formulated with a different biodegradable organic compound and a different chemoattractant agent.

6.2 Method

6.2.1 All formulations were prepared according to Table 13, 14, 15 and 16.

6.2.2 Glove samples were produced by dipping a former into the formulation to be tested, drying/curing the film composition, and removing from the former. Physical properties of the samples were tested at 22°C.

Table 13: Natural rubber latex formulation with solubilised biodegradation additive additive - Formulation 4:

Table 14: Natural rubber latex formulation with solubilised biodegradation additive

- Formulation 5

Table 15: Nitrile butadiene rubber latex formulation with solubilized biodegradation additive - Formulation 6

Table 16: Polychloroprene latex formulation with solubilized biodegradation additive - Formulation 7

6.3 Results

Table 17: Physical properties of gloves:

6.4 Conclusions

6.4.1 Gloves having statistically similar properties can be manufactured from a variety of elastomers formulated with a solubilised biodegradation agent containing different soluble biodegradable organic compounds and different chemoattractant agents.

Examples showing physical properties of elastomeric articles

7 Example 7: Physical properties of unaged and aged gloves prepared using the solubilised biodegradation additive

7.1 Method

7.1.1 Gloves were produced in accordance with conventional glove dipformation steps using the formulations indicated, and then aged in an oven for 22 hours at 100°C. 7.1.2 The gloves were then conditioned and tested for tensile strength and force at break (FAB).

72. Results and Discussion

Table 18: Formulation 8:

Table 19: Physical properties of tested gloves

8 Example 8: Anaerobic biodegradation through biomethane potential test for glove using solubilised biodegradation additive

Table 20: Formulation 9:

Table 21 : Formulation 10:

Biomethane Potential Test

The Biomethane Potential testing (BMP) is a common method used by research laboratories to study biodegradation behaviour of materials in landfill environments. It is used to validate if a material is able to be digested by microorganisms within an environment with no/limited oxygen and light. This test measures the conversion of carbon in the test specimen to gaseous carbon such as carbon dioxide (CO2) and methane (CH₄), from which the % of biodegradation is calculated. In the test, a test substrate is mixed with an anaerobic bacteria culture, also known as the inoculum, normally retrieved from an active digester. The inoculum may be a soil substrate containing microorganisms or a suspension of microorganisms (e.g., bacteria).

The biomethane potential test was performed on the following samples:

(a) A positive control - cellulose paper - used for comparison against the test samples.

(b) Gloves produced from Formulation 1 (control containing no solubilised biodegradation additive)

(c) Gloves produced from Formulation 9 (containing solubilised biodegradation additive)

(d) Gloves produced from Formulation 10 (containing a biodegradable organic compound that was not able to be solubilised prior to incorporation into the elastomeric film-forming composition.)

The BMP test was carried out over 30 days, and the results are presented in Figure 2. In the results, the percent biodegraded refers to the total amount of carbonaceous gas produced during the test, less the amount of gas produced by the inoculum.

The gloves of Formulation 9, containing 2.3 phr of the solubilized biodegradation additive, were found to achieve a degree of biodegradation of 5.6 % compared to the gloves of Formulation 1 containing no solubilised biodegradation additive, which showed negligible biodegradation (in fact, a negative outcome was achieved). Furthermore, Formulation 10 containing biodegradable organic compound in the form of starch also failed to show any positive biodegradation results.

9 Example 9: Anaerobic biodegradation assessment of gloves made with solubilised biodegradation additive using ASTM D5526

Table 22: Example using insoluble biodegradation additive

• pH of all formulations maintained at similar level: pH 9.8

Table 23: Formulation

Table 24: Physical properties (before aging)

The increase in M500 to 12.14 indicates a much stiffer glove.

Table 25: Physical properties (after aging)

It is observed that the glove made by the prior art method (last line of table) is inferior, in terms of its lower tensile strength and force at break, compared to the glove of the present application prepared with the solubilised biodegradation additive.

ASTM D5526 - Standard Test Method for Determining Anaerobic Biodegradation of Plastic Materials Under Accelerated Landfill Conditions

The test method of ASTM D5526 allows for the determination of the degree and rate of anaerobic biodegradation of materials in an accelerated-landfill test environment. This test method is also designed to produce mixtures of household waste and plastic materials after different degrees of decomposition under conditions that resemble landfill conditions. The test materials are mixed with pre-treated household waste and exposed to a methanogenic inoculum derived from anaerobic digesters operating only on pre-treated household waste. The anaerobic decomposition occurs under dry (more than 30 % total solids) and static non-mixed conditions. The mixtures obtained after this test method can be used to assess the environmental and health risks of materials that are degraded in a landfill.

INOCULUM COLLECTION AND CONDITIONING

The prepared inoculum is an anaerobically digested sewage sludge mixed with household waste, which needs to undergo a short mesophilic post-fermentation of approximately 7 days at the same dry-matter content as the digester from which it was derived. This means that the inoculum is not fed but is allowed to post-ferment anaerobically by itself. This is to ensure that large, easily biodegradable particles are degraded during this period and to reduce the background level of degradation of the inoculum itself.

METHODOLOGY:

Inoculum Medium: Remove enough inoculum (approximately 15 kg) from the postfermentation vessel and mix carefully and consistently by hand in order to obtain a homogeneous medium. The test is performed on three replicates of each of (a) a blank (inoculum only), (b) a Positive control (a Reference material, being a thin-layer chromatography cellulose) and (c) the test substance being evaluated.

Weigh and combine the components and adjust the dry matter content of the final mixtures with water to reach the desired dry-matter content for each vessel. Weigh out 600 g on a dry-weight basis of pre-treated household waste and mix it with 100 g on a dry-weight basis of mesophilic anaerobic inoculum from a continuously operating digester or 150 g on a dry-weight basis of anaerobic inoculum from a batch digester. Add 60 to 100 g of dry matter of the test substance. Add water until the appropriate final dry matter content is reached. (In order to reach 60 % dry matter content in the mixture, it is necessary, in some cases, to have water removed prior to combining the different components of the mixture. This can be accomplished by drying the pretreated household waste or centrifuging the anaerobic inoculum.) Mix the required amounts of pre-treated household waste, inoculum, and test substance in a small container for 2 to 3 min. Introduce the mixture in the vessel, weigh the vessel with all of the contents, and close it airtight. Prepare the pressure vessels in the triplicate at each of the following dry matter contents: 35, 45, and 60 %, so nine vessels are necessary for each sample. The blanks consist of 600 g dry matter of pre-treated household waste and anaerobic inoculum at the respective total dry-matter contents. As references, thin-layer chromatography cellulose must be used as a positive control. The blank and reference are performed in triplicate at the three different dry-matter contents.

Start-Up Procedure: After all reactors are filled and closed, place them in incubators at 35 ± 2°C. Acclimate the reactors for approximately 1 h and release the pressure, which originates from the temperature increase, to the atmosphere. Incubate the reactors in the dark for a period of four months.

Check the gas production (measured as a pressure increase) at least weekly. Analyze the gas composition biweekly. Determine the methane and carbon dioxide concentration by using gas chromatography.

The percent biodegradation of Positive control (Reference material) and Test sample (Formulation 9 containing solubilised biodegradation additive Sample I, Table 20) was calculated by the measured cumulative carbon dioxide and methane production from each flask after subtracting carbon dioxide evolution and methane evolution from the blank samples at the end of 180 days of testing. Calculations were based on Total Organic Carbon obtained of both Positive control (Reference material) and Test sample. Table 26: Percentage biodegradability of Test Sample with respect to Positive control (Reference material) Cellulose.

The Percent weight loss was calculated based on the initial weight and final weight of the sample after the 180 days study.

Table 27: Percent weight loss of Test sample.

Conclusion:

Considering the cumulative gas production and its analysis indicates that the process of biodegradation has occurred. After 180 days of incubation, the level of biodegradation for the Positive control (Reference material) was 91 .08% while test sample showed 20.33% relative to the Positive control (Reference material).

10 Example 10: Terrestrial plant toxicity assessment of gloves made with solubilised biodegradation additive using ASTM E 1963

TEST SAMPLE

A biodegradable nitrile glove sample (Formulation 9 containing solubilised biodegradation additive Sample I, Table 20) was subjected to standard ASTM D5526 (Example 9) and then the biodegraded residue was subjected to toxicity test as per standard ASTM E1963.

METHOD

Seeds are screened in advance to achieve uniform size, then stored in cool dry place. Seeds are then planted, 2-4 per cell, depending on size to a depth of 1 .5 to 2 times the seed diameter in a mixture of potting soil. The test is run in duplicate with 5-20 seeds per duplicate. Flats are then placed under fluorescent lights with an illumination of 100 to 200 pmol rrr²s“¹ for 12 hrs to 16 hrs per day.

The test conditions should approximate those conditions necessary for normal growth for the species and varieties tested. The following conditions were used:

• temperature: 22°C ± 10°C.

• humidity: above 30 %;

• photoperiod: minimum 16-hour light.

• light intensity: 100 to 200 pmol m^-2s“¹ for 12 hrs to 16 hrs per day.

Control and treated plants were kept under the same environmental conditions and adequate measures were taken to prevent cross exposure. This study included the following positive control and test plant species:

Positive Control: Boric Acid, a watering solution of Boric Acid at desired concentration is added to the test soil. Test species: 1 : Family: Gramineae (Poaceae); Species: Triticum aestivum; Common name: Wheat. 2: Family: Brassica (Poaceae); Species: Brassica juncea; Common name: Mustard

RESULTS The biodegraded residue of the biodegradable nitrile glove sample was mixed in different concentration in natural soil. Seeds of test species were planted in the soil. Concentrations of 10 mg/kg, 100 mg/kg, 1000 mg/kg, 5000 mg/kg, and 10,000 mg/kg were tested.

Table 27: Average germination rate and shoot weight, shoot and root length of Triticum aestivum seed.

Table 28: Average germination rate and shoot weight, shoot and root length of Triticum aestivum seed.

Table 29: Average germination rate and shoot weight, shoot and root length of Brassica juncea seed.

Table 30. Average germination rate and shoot weight, shoot and root length of Brassica juncea seed.

The results showed that the biodegraded residue of the biodegradable nitrile glove sample had no effect on the plant growth and resulted in no visible damage to plants, as demonstrated in Figures 3 and 4.

CONCLUSIONS There is no toxic effect of different concentrations of the biodegraded additive of the biodegradable nitrile glove sample on the survival, growth, and development of Triticum aestivum and Brassica juncea seeds.

Various modifications may be made to the processes and products described in the detailed description and examples, without departing from the spirit and scope of the invention.

Claims

CLAIMS:

1 . A method for the production of a biodegradable elastomeric article, the method comprising:

- preparing an elastomeric film-forming composition by combining an elastomer and one or more cross-linking agents with the solubilised biodegradation additive;

- dipping a former into the elastomeric film-forming composition to produce a layer of the elastomeric film-forming composition on the former; drying and/or curing the layer of elastomeric film-forming composition on the former to produce the elastomeric article; and removing the elastomeric article from the former.

2. The method of claim 1 , comprising preparing the solubilised biodegradation additive by dissolving a biodegradable organic compound in water with the pH increasing agent.

3. The method of claim 2, wherein the biodegradable organic compound is a water-soluble or water-miscible biodegradable organic compound selected from the group consisting of disaccharides and polysaccharides, cyclic esters, polyesters, cyclic amides, polyamides, proteins and lipid-derived biopolymers.

4. The method of claim 2 or claim 3, wherein the biodegradable organic compound has a molecular weight of not more than 10,000 g/mol, or = 8,000, or

6,000, or s=5,000, or ^4,000, or ^3,000, or ^2,000, or ^1 ,000 or <1 ,000 or s=500, or s£200 or <200 g/mol.

5. The method of any one of claims 2 to 4, comprising preparing the solubilised biodegradation additive with a concentration of the biodegradable organic compound of at least 0.05% w/w and up to 10% w/w, based on the total weight of the solubilised biodegradation additive.

6. The method of claim 5, wherein the concentration of the biodegradable organic compound is between 0.1% and 8%, or between 0.1% and 5%, or between 0.2% and 5%.

7. The method of any one of claims 2 to 6, comprising preparing the solubilised biodegradation additive with a concentration of the biodegradable organic compound of at least 10% and up to 90% by weight of the non-water components of the solubilised biodegradation additive, or at a total solids content of between 20% to 50% based on the total solids in the solubilised biodegradation additive.

8. The method of any one of claims 1 to 7, further comprising preparing the solubilised biodegradation additive with a chemoattractant.

9. The method of claim 8, comprising preparing the solubilised biodegradation additive with a concentration of the chemoattractant of up to 10% w/w, based on the total weight of the solubilised biodegradation additive, or a concentration of the chemoattractant of up to 5%, or between 0.05% and 4% w/w, or between 0.05% and 2% w/w, or between 0.1% and 2% w/w based on the total weight of the solubilised biodegradation additive.

10. The method of claim 8 or claim 9, comprising preparing the solubilised biodegradation additive with a concentration of the chemoattractant of at least 1% and up to 25% by weight based on the non-water components of the solubilised biodegradation additive, or at a total solids content of between 2% to 20% based on the total solids of the solubilised biodegradation additive.

11 . The method of any one of claims 8 to 10, comprising preparing the solubilised biodegradation additive with a relative amount of the chemoattractant to biodegradable organic compound in the range of between 0.1 :1 to 1 :1 , by weight.

12. The method of any one of claims 1 to 11 , wherein the pH increasing agent is selected from one or more alkali hydroxides.

13. The method of claim 12, comprising preparing the solubilised biodegradation additive with an amount of pH increasing agent that is at least 0.05% w/w and up to 10% w/w, based on the total weight of the solubilised biodegradation additive, or between 0.1% and 10%, or between 0.2% and 8%, or between 0.5% and 5% w/w.

14. The method of claim 12 or claim 13, comprising preparing the solubilised biodegradation additive with a concentration of the pH increasing additive of at least 20% and up to 90% by weight based on the non-water components of the solubilised biodegradation additive, or at a total solids content of between 20% to 70% based on the total solids of the solubilised biodegradation additive.

15. The method of any one of claims 1 to 14, comprising preparing the solubilised biodegradation additive with said dispersant or surfactant.

16. The method of claim 15, wherein the dispersant or surfactant is selected from the group consisting of salts of sulfonates and sulfates; salts of carboxylic acid and salts of phosphates.

17. The method of claim 15 or claim 16, comprising preparing the solubilised biodegradation additive with an amount of dispersant or surfactant that is up to 5% w/w, based on the total weight of the solubilised biodegradation additive, or between 0.05% and 4% w/w, or between 0.05% and 2% w/w, or between 0.1% and 2% w/w.

18. The method of any one of claims 15 to 17, comprising preparing the solubilised biodegradation additive with a concentration of the dispersant or surfactant of at least 0.1% and up to 25% by weight based on the non-water components of the solubilised biodegradation additive, or at a total solids content of between 2% to 20% based on the total solids of the solubilised biodegradation additive.

19. The method of any one of claims 1 to 18, comprising preparing the solubilised biodegradation additive without microbes.

20. The method of any one of claims 1 to 19, comprising formulating the solubilised biodegradation additive, and maintaining the solubilised biodegradation additive in a solubilised and stabilised state for at least 3 months, or at least 6 months, or at least 9 months, or at least 12 months, or at least 15 months, or at least 18 months, or at least 24 months, or at least 30 months, or at least 36 months, prior to combining with the elastomer and one or more cross-linking agents to form the elastomeric film-forming composition.

21 . The method of any one of claims 1 to 20, comprising preparing the solubilised biodegradation additive without carrier resin, or without filler, or without swelling agent, or without each of a carrier resin, filler and swelling agent.

22. The method of any one of claims 1 to 21 , wherein the step of preparing an elastomeric film-forming composition by combining the elastomer and one or more cross-linking agents with the solubilised biodegradation additive comprises incorporating the solubilised biodegradation additive in an amount of between 0.1 phr and lO phr, or between 0.1 phr - 5.0 phr, between 0.1 phr - 4.0 phr, between 0.1 phr - 3.5 phr or between 0.1 phr - 3.0 phr.

23. The method of any one of claims 1 to 22, wherein the elastomer is selected from natural or synthetic rubber, nitrile rubber, polyisoprene and polychloroprene, each of which may be carboxylated or non-carboxylated, and blends or co-polymers thereof.

24. The method of any one of claims 1 to 23, wherein the step of preparing an elastomeric film-forming composition by combining the elastomer and one or more cross-linking agents with the solubilised biodegradation additive further comprises incorporating an antimicrobial agent into the elastomeric film-forming composition in an amount of 0.01 phr to 20 phr.

25. The method of any one of claims 1 to 24, comprising dipping the former into a second elastomeric film-forming composition, for the production of an additional layer of elastomeric film-forming composition on the former.

26. The method of claim 25, wherein the second elastomeric film-forming composition is of a different formulation as compared to that used for the dipping step referred to in claim 1 .

27. The method of claim 25, wherein the second elastomeric film-forming composition is free of solubilised biodegradation additive.

28. The method of claim 25, wherein the second elastomeric film-forming composition is of the same composition as that used for dipping step referred to in claim 1 .

29. The method of any one of claims 1 to 28, wherein the biodegradable organic compound is soluble at a pH between 8.0 and 13.0.

30. The method of any one of claims 1 to 28, wherein the biodegradable organic compound is soluble at a pH between 11 .0 and 13.0.

31 . An elastomeric film-forming composition for the production of biodegradable elastomeric articles, the elastomeric film-forming composition comprising a combination of:

- a solubilised biodegradation additive comprising a biodegradable organic compound dissolved in water with a pH increasing agent and optionally a dispersant or surfactant; an elastomer; and one or more cross-linking agents.

32. The elastomeric film-forming composition of claim 31 , wherein the biodegradable organic compound is a water-soluble or water-miscible biodegradable organic compound selected from the group consisting of disaccharides and polysaccharides, cyclic esters, polyesters, cyclic amides, polyamides, proteins and lipid-derived biopolymers.

33. The elastomeric film-forming composition of claim 31 or claim 32, wherein the biodegradable organic compound has a molecular weight of not more than 10,000

34. The elastomeric film-forming composition of any one of claims 31 to 33, wherein the concentration of the biodegradable organic compound is at least 0.05% w/w and up to 10% w/w, based on the total weight of the solubilised biodegradation additive.

35. The elastomeric film-forming composition of claim 34, wherein the concentration of the biodegradable organic compound is between 0.1% and 8%, or between 0.1% and 5%, or between 0.2% and 5% by weight, based on the total weight of the solubilised biodegradation additive.

36. The elastomeric film-forming composition of any one of claims 31 to 35, wherein the concentration of the biodegradable organic compound is at least 10% and up to 90% by weight of the non-water components of the solubilised biodegradation additive, or has a solids content of between 20% to 50% by weight based on the total solids of the solubilised biodegradation additive.

37. The elastomeric film-forming composition of any one of claims 31 to 36, wherein the solubilised biodegradation additive comprises a chemoattractant.

38. The elastomeric film-forming composition of claim 37, wherein the concentration of the chemoattractant is up to 10% w/w, based on the total weight of the solubilised biodegradation additive, or a concentration of the chemoattractant is up to 5%, or between 0.05% and 4% w/w, or between 0.05% and 2% w/w, or between 0.1% and 2% w/w based on the total weight of the solubilised biodegradation additive.

39. The elastomeric film-forming composition of claim 37 or claim 38, wherein the concentration of the chemoattractant is at least 1% and up to 25% by weight based on the non-water components of the solubilised biodegradation additive, or the chemoattractant constitutes between 2% to 20% by weight of the solids, based on the total solids of the solubilised biodegradation additive.

40. The elastomeric film-forming composition of any one of claims 37 to 39, wherein the relative amount of the chemoattractant to biodegradable organic compound is in the range of between 0.1 :1 to 1 :1 , by weight.

41 . The elastomeric film-forming composition of any one of claims 31 to 40, wherein the pH increasing agent is selected from one or more alkali hydroxides.

42. The elastomeric film-forming composition of claim 41 , wherein the amount of pH increasing agent is at least 0.05% w/w and up to 10% w/w, based on the total weight of the solubilised biodegradation additive, or between 0.1% and 10%, or between 0.2% and 8%, or between 0.5% and 5% w/w.

43. The elastomeric film-forming composition of claim 41 or claim 42, wherein the concentration of the pH increasing additive is at least 20% and up to 90% by weight based on the non-water components of the solubilised biodegradation additive, or the pH increasing agent constitutes 20% to 70% by weight of the solids, based on the total solids of the solubilised biodegradation additive.

44. The elastomeric film-forming composition of any one of claims 31 to 43, comprising said dispersant or surfactant.

45. The elastomeric film-forming composition of claim 44, wherein the dispersant or surfactant is selected from the group consisting of salts of sulfonates and sulfates; salts of carboxylic acid and salts of phosphates.

46. The elastomeric film-forming composition of claim 44 or claim 45, wherein the amount of dispersant or surfactant is up to 5% w/w, based on the total weight of the solubilised biodegradation additive, or is between 0.05% and 4% w/w, or between 0.05% and 2% w/w, or between 0.1% and 2% w/w.

47. The elastomeric film-forming composition of any one of claims 44 to 46, wherein the concentration of the dispersant or surfactant is at least 0.1% and up to 25% by weight based on the non-water components of the solubilised biodegradation additive, or the dispersant or surfactant constitutes between 2% to 20% of the solids, based on the total solids of the solubilised biodegradation additive.

48. The elastomeric film-forming composition of any one of claims 31 to 47, wherein the solubilised biodegradation additive is free of microbes.

49. The elastomeric film-forming composition of any one of claims 31 to 48, wherein the solubilised biodegradation additive is free of carrier resin, or free of filler, or free of swelling agent, or free of each of a carrier resin, filler and swelling agent.

50. The elastomeric film-forming composition of any one of claims 31 to 49, wherein the amount of solubilised biodegradation additive is between 0.1 phr and 10 phr, or between 0.1 phr - 5.0 phr, between 0.1 phr - 4.0 phr, between 0.1 phr - 3.5 phr or between 0.1 phr - 3.0 phr.

51 . The elastomeric film-forming composition of any one of claims 31 to 50, wherein the elastomer is selected from natural or synthetic rubber, nitrile rubber, polyisoprene and polychloroprene, each of which may be carboxylated or non- carboxylated, and blends or co-polymers thereof.

52. The elastomeric film-forming composition of any one of claims 31 to 51 , further comprising an antimicrobial agent in an amount of 0.01 phr to 20 phr.

53. The elastomeric film-forming composition of any one of claims 31 to 52, wherein the biodegradable organic compound is soluble at a pH between 8.0 and 13.0.

54. The elastomeric film-forming composition of any one of claims 31 to 52, wherein the biodegradable organic compound is soluble at a pH between 11 .0 and 13.0.

55. A biodegradable elastomeric article produced by the method of any one of claims 1 to 30, or from the elastomeric film-forming composition of any one of claims 31 to 54.

56. A biodegradable elastomeric article comprising the cured product of an elastomeric film-forming composition that comprises the combination of:

- an elastomer; and one or more cross-linking agents.

57. The biodegradable elastomeric article of claim 56, wherein the biodegradable organic compound is a water-soluble or water-miscible biodegradable organic compound selected from the group consisting of disaccharides and polysaccharides, cyclic esters, polyesters, cyclic amides, polyamides, proteins and lipid-derived biopolymers.

58. The biodegradable elastomeric article of claim 56or claim 57, wherein the biodegradable organic compound has a molecular weight of not more than 10,000

59. The biodegradable elastomeric article of any one of claims 56 to 58, wherein the concentration of the biodegradable organic compound is at least 0.05% w/w and up to 10% w/w, based on the total weight of the solubilised biodegradation additive.

60. The biodegradable elastomeric article of claim 59, wherein the concentration of the biodegradable organic compound is between 0.1% and 8%, or between 0.1% and 5%, or between 0.2% and 5% by weight, based on the total weight of the solubilised biodegradation additive.

61 . The biodegradable elastomeric article of any one of claims 56 to 60, wherein the concentration of the biodegradable organic compound is at least 10% and up to 90% by weight of the non-water components of the solubilised biodegradation additive, or has a solids content of between 20% to 50% by weight based on the total solids of the solubilised biodegradation additive.

62. The biodegradable elastomeric article of any one of claims 56 to 61 , wherein the solubilised biodegradation additive comprises a chemoattractant.

63. The biodegradable elastomeric article of claim 62, wherein the concentration of the chemoattractant is up to 10% w/w, based on the total weight of the solubilised biodegradation additive, or a concentration of the chemoattractant is up to 5%, or between 0.05% and 4% w/w, or between 0.05% and 2% w/w, or between 0.1% and 2% w/w based on the total weight of the solubilised biodegradation additive.

64. The biodegradable elastomeric article of claim 62 or claim 63, wherein the concentration of the chemoattractant is at least 1% and up to 25% by weight based on the non-water components of the solubilised biodegradation additive, or the chemoattractant constitutes between 2% to 20% by weight of the solids, based on the total solids of the solubilised biodegradation additive.

65. The biodegradable elastomeric article of any one of claims 62 to 64, wherein the relative amount of the chemoattractant to biodegradable organic compound is in the range of between 0.1 :1 to 1 :1 , by weight.

66. The biodegradable elastomeric article of any one of claims 56 to 65, wherein the pH increasing agent is selected from one or more alkali hydroxides.

67. The biodegradable elastomeric article of claim 66, wherein the amount of pH increasing agent is at least 0.05% w/w and up to 10% w/w, based on the total weight of the solubilised biodegradation additive, or between 0.1% and 10%, or between 0.2% and 8%, or between 0.5% and 5% w/w.

68. The biodegradable elastomeric article of claim 66 or claim 67, wherein the concentration of the pH increasing additive is at least 20% and up to 90% by weight based on the non-water components of the solubilised biodegradation additive, or the pH increasing agent constitutes 20% to 70% by weight of the solids, based on the total solids of the solubilised biodegradation additive.

69. The biodegradable elastomeric article of any one of claims 56 to 68, comprising said dispersant or surfactant.

70. The biodegradable elastomeric article of claim 69, wherein the dispersant or surfactant is selected from the group consisting of salts of sulfonates, salts of sulfates; salts of carboxylic acid and salts of phosphates.

71 . The biodegradable elastomeric article of claim 69 or claim 70, wherein the amount of dispersant or surfactant is up to 5% w/w, based on the total weight of the solubilised biodegradation additive, or is between 0.05% and 4% w/w, or between 0.05% and 2% w/w, or between 0.1% and 2% w/w.

72. The biodegradable elastomeric article of any one of claims 69 to 71 , wherein the concentration of the dispersant or surfactant is at least 0.1% and up to 25% by weight based on the non-water components of the solubilised biodegradation additive, or the dispersant or surfactant constitutes between 2% to 20% of the solids, based on the total solids of the solubilised biodegradation additive.

73. The biodegradable elastomeric article of any one of claims 56 to 72, wherein the solubilised biodegradation additive is free of microbes.

74. The biodegradable elastomeric article of any one of claims 56 to 73, wherein the solubilised biodegradation additive and the biodegradable elastomeric article are free of carrier resin, or free of filler, or free of swelling agent, or free of each of a carrier resin, filler and swelling agent.

75. The biodegradable elastomeric article of any one of claims 56 to 74, wherein the amount of solubilised biodegradation additive is between 0.1 phr and 10 phr, or between 0.1 phr - 5.0 phr, between 0.1 phr - 4.0 phr, between 0.1 phr - 3.5 phr or between 0.1 phr - 3.0 phr.

76. The biodegradable elastomeric article of any one of claims 56 to 75, wherein the elastomer is selected from natural or synthetic rubber, nitrile rubber, polyisoprene and polychloroprene, each of which may be carboxylated or non-carboxylated, and blends or co-polymers thereof.

77. The biodegradable elastomeric article of any one of claims 56 to 76, further comprising an antimicrobial agent in an amount of 0.01 phr to 20 phr.

78. The biodegradable elastomeric article of any one of claims 56 to 77, wherein the thickness of the article is between 0.01 mm and 3.0 mm, or between 0.01 mm and 2.0 mm, or between 0.01 mm and 1.0 mm, or between 0.01 mm and 0.5 mm, or between 0.01 mm and 0.1 mm.

79. The biodegradable elastomeric article of any one of claims 56 to 78, wherein the modulus at 500% before aging is up to 50MPa.

80. The biodegradable elastomeric article of any one of claims 56 to 79, wherein the tensile strength is within 10% of the tensile strength of a comparison article of the same formulation and thickness but without the solubilised biodegradation additive.

81 . The biodegradable elastomeric article of any one of claims 56 to 80, wherein the elongation at break before aging is at least 400%.

82. The biodegradable elastomeric article of any one of claims 56 to 81 , wherein the biodegradable organic compound is soluble at a pH between 8.0 and 13.0.

83. The biodegradable elastomeric article of any one of claims 56 to 81 , wherein the biodegradable organic compound is soluble at a pH between 11 .0 and 13.0.

84. The biodegradable elastomeric article of any one of claims 56 to 83, consisting essentially of the cured product of the elastomeric film-forming composition defined in claim 56, or comprising one or more additional elastomeric film layer(s) of a different composition.

85. The biodegradable elastomeric article of any one of claims 55 to 84, wherein the article degrades at least 5%, or at least 10%, or at least 15%, or at least 20%, when tested in accordance with the procedure specified in ASTM D5526.

86. The method for the production of a biodegradable elastomeric article of any one of claims 1 to 30, elastomeric film-forming composition of any one of claims 31 to 54, or biodegradable elastomeric article of any one of claims 55 to 85, wherein the solubilised biodegradation additive is characterizable as nontoxic to plants or plant parts when tested in accordance with the procedures of ASTM E1963.