WO2021053561A1

WO2021053561A1 - Radiation-attenuating compositions

Info

Publication number: WO2021053561A1
Application number: PCT/IB2020/058651
Authority: WO
Inventors: Pierre Hoerner; Sébastien TREILHES; Mohd Zafrul Bin ZAINAL
Original assignee: Ineo-Tech Sdn, Bhd
Priority date: 2019-09-20
Filing date: 2020-09-17
Publication date: 2021-03-25

Abstract

Provided are radiation-attenuating compositions formed from mixtures of structural polymers, plasticizers and radiopaque substances. The compositions can be formed into thin films which find use in the manufacture of gloves, particularly gloves for medical use. The gloves have advantageous properties in terms of flexibility and comfort and provide sufficient and consistent attenuation of X-rays.

Description

RADIATION-ATTENUATING COMPOSITIONS

FIELD

[0001] This disclosure generally relates to radiation-attenuating compositions formed from mixtures of structural polymers, plasticizers and radiopaque substances. The compositions can be formed into thin films which find use in the manufacture of gloves, particularly for surgical use. The gloves have advantageous properties in terms of flexibility and comfort and provide sufficient and consistent attenuation of X-rays.

BACKGROUND

[0002] Diagnostic radiology, nuclear medicine and radiotherapy have become indispensable tools in many medical fields.

[0003] Although the properties inherent to ionizing radiation, especially X-ray and gamma (g) radiation offer many advantages, for example in diagnostic and surgical guiding procedures, the frequent use of such techniques exposes patients and healthcare workers to increasing radiation doses.

[0004] This exposure most particularly affects medical staff, whose almost daily exposure to radiation may lead to accumulated doses that could be dangerous to their health. This is especially the case in interventional surgery, and orthopaedic and vascular surgery, where the medical staff work within the X-ray radiation field in the immediate vicinity of the patient.

[0005] Despite the increased use of devices such as needle holders, which are designed to reduce radiation exposure to the hands, the hands of the physician must still perform several manipulations close to the scanning plate and the patient.

[0006] Placing the hands into the direct beam should be avoided, but can inadvertently occur. However, the main source of exposure to the operator is scattered radiation from the patient, meaning that the operator’s body is widely exposed to radiation even if the operator takes all necessary precautions not to enter the direct field.

[0007] Studies have shown that a surgeon’s extremities receive the greatest radiation dose, followed by the eyes and neck. This suggests the need for individual monitoring devices worn on specific body parts of surgeons who regularly perform fluoroscopy.

[0008] Protocols to minimize radiation exposure should be constantly revised and make use of the “as-low-as-reasonably-achievable” principle in every setting.

[0009] Basic dose mitigation approaches recommend reducing fluoroscopy time, increasing the distance from the source and using adequate radiation-attenuating protection devices. [00010] For the protection of hands, radiation-attenuating gloves have been commercially available for decades. Conventional radiation-attenuating gloves are made of rubber (either natural rubber or synthetic rubber) filled with substantial amounts of radiopaque substances to attenuate the radiation. The radiopaque substances are elements with atomic numbers large enough to attenuate X-Rays.

[00011] Radiopaque substances are mainly based on lead in the form of metal, metal oxides (PbCk, Pb₂C>3, PbiC ) or metal salts. For example, such substances have been described in U.S. Pat. No. 3,185,751 andU.S. Pat. No. 3,883,749 for producing, by a dipping process, surgical gloves made of natural latex and polyurethane respectively.

[00012] However, lead particles present toxicity issues, especially as lead could come into contact with the wearer’s skin and the patient’s wound. In addition, the use of lead more generally poses an environmental problem requiring specific devices for disposal of the waste from the manufacturing process and for the finished products.

[00013] More recently, lead has been replaced in favour of elements whose efficacy in attenuating X-rays is comparable in the energy ranges generally used in interventional surgery (between 40 and 120 kV), such as bismuth and tungsten. For example, in US Patent Application Publication No. 2004/0262546, the element bismuth is used in the oxide form dispersed in a natural rubber matrix for the manufacture of surgical gloves. Similarly, the use of the element tungsten is described in U.S. Pat. No. 5,215,701 and U.S. Pat. No. 5,548,125 for producing surgical gloves or gloves for medical use that are made of natural rubber or based on an ethylene-propylene diene (EPDM) terpolymer.

[00014] Conventional radiation-attenuating gloves typically contain large amounts, up to 65% of their weight, of metal containing particles, such as lead, tungsten or bismuth. Introducing such high amounts of rigid particles in a rubber have detrimental effects on the rubber properties: as a general rule of thumb, the resulting rubber film becomes stiffer and less flexible as the quantity of metal containing particles increases in the glove. In contrast, the radiation-attenuating properties increase as a function of the quantity of metal containing particles inside the material.

[00015] From a manufacturing perspective, the use of some of these metallic based particles is known for accelerating vulcanization phenomena in mixtures formulated from natural or synthetic latex and therefore it considerably reduces the usage time of these mixtures. Thus, at a relatively high particle loading, a latex mixture deteriorates over storage time and can quickly become unusable for manufacturing radio-attenuating gloves by a dipping-type preparation process. [00016] In addition, high particle content also disturbs the film-forming mechanism by interfering with latex rubber particle stability and coalescence. As a result, it is more difficult to make a film with consistent performance. Also, the manufacture of gloves utilizing conventional latex dispersions is difficult.

[00017] Accordingly, manufacturers of conventional radiation-attenuating gloves are forced to make compromises, especially between glove dexterity and radiation protection level.

[00018] Some commercially available radiation attenuating gloves contain lower amounts of radiopaque elements (40-50% by weight) and/or are relatively thin (0.20-0.3 mm). Consequently, their attenuation performance, as evaluated according to EN61331, is relatively low, sometimes below 50% at 60 and at 80kVp, or even less. However, the clinical interest in these gloves is questionable, as they could raise a risk of a “false protection feeling” for the users, who could be less vigilant and less compliant with good practices.

[00019] To reach a minimum of 50% (i.e., to be able to stop at least half of the incoming radiation) of the radiation at 80kVp (as measured according to EN61331) conventional gloves need to have a thickness of around 0.3 mm and a radiopaque weight fraction in the range 60-65%. This is typical of what it is currently achieved in the market.

[00020] However, such a glove is already quite stiff and less flexible, and it significantly lowers the surgeon’s dexterity and tactile sensation.

[00021] This inflexibility restricts the agile movement of the physician’ s hand that is necessary for delicate procedures. That is, these gloves cause the physician’s fingers to lose their dexterity and tactile sensation. Tactile sensation is an important requirement for operators performing fluoroscopy as it is used by surgeons to help guide their hands and fingers when they are inside the patient and hidden from direct view.

[00022] Interventional surgery, but also orthopaedic and vascular surgeries, routinely use fluoroscopy techniques to assist surgeons in guidance procedures. These procedures are surgical procedures that require the operating room personnel to use only sterile devices to strictly comply with aseptic requirements.

[00023] International infection prevention precautions applying these procedures recommend the use of two pairs of superposed gloves, in a practice called “double gloving”. The use of double gloves provides superior barrier protection for the entire duration of the surgical procedure. Studies have demonstrated that double gloving decreases the likelihood of unnoticed glove perforation, and decreases the risk of surgical site infection. [00024] Double gloving practice is widely used by surgeons performing “aseptic surgery”, which is the case for most orthopaedic and vascular procedures. Therefore, under these circumstances, operators wear a standard surgical glove on top of the sterile radiation-attenuation glove, which further decreases tactile sensation and dexterity.

[00025] Accordingly, the use of conventional radiation-attenuating protective gloves raises significant issues when considering the importance of gloves in both surgical practice and patient safety. Conventional radiation-attenuation gloves are not suitable to be used by most surgeons due to the limited dexterity they provide. Double gloving, which is the recommended practice, is almost impossible to perform with conventional radiation-attenuating gloves. Further, the models providing improved dexterity, due to thinner walls, do not offer an adequate level of radiation attenuating performance.

[00026] Radiation-attenuating lotion has recently been developed to provide hand protection without compromising dexterity. The lotion consists of an aqueous organic carrier and 75 weight % of bismuth oxide (BriCh) ceramic powder. The organic carrier comprises lubricants, humectants and surfactants such as glycerin, glycol stearate and polyethylene glycol stearate, and emulsifiers such as glyceryl stearate. The ceramic powder is blended to make a lotion with a creamy texture, qualitatively like hand lotion.

[00027] For a given lotion composition, the radiation-attenuation efficacy is correlated with the thickness of the lotion which is applied on the hand surface. However, homogeneous thickness is challenging to achieve when applying a lotion onto the hand. Even if homogenous thickness could be applied at the beginning, the lotion thickness will rapidly change during practice: the friction between the glove and the cream will displace the cream from points were the contact pressure is high, to points with lower contact pressure. This results in some areas where protection will be totally lost. Therefore, an even protection cannot be maintained all over the hand.

[00028] Furthermore, placing lotion between two glove layers is not a useful option as it allows the external glove to slip on top of the inner glove, which consequently reduces the tactile sensitivity of the operator.

[00029] In conclusion, there remains a need for a radiation protective shield offering a sufficient and consistent radiation protection level and which additionally has a minimum effect on tactile sensation and surgeon dexterity. The present disclosure addresses this need.

[00030] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgement or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

SUMMARY

[00031] The present disclosure relates to a new type of radiation-attenuating composition comprising plasticized polymers and radiopaque substances. The compositions find particular use in the manufacture of thin walled articles, such as gloves. Gloves manufactured from the compositions have improved properties in terms of flexibility and comfort compared to gloves derived from prior art compositions and additionally provide a sufficient and consistent attenuation level of X-rays.

[00032] In one aspect the present disclosure provides a radiation-attenuating composition comprising:

(a) one or more structural polymers;

(b) one or more plasticizers; and

(c) one or more radiopaque substances.

[00033] The radiation-attenuating composition may be processed into the form of a glove that offers sufficient resistance so that it does not suffer damage when donned. The glove finds particularly useful practical application when worn under a conventional surgical glove for the protection of the operator when exposed to radiation during surgical procedures.

[00034] Advantageously, the surgeon can comply with double gloving practice, and wear the surgical glove he or she is already familiar with as an outer layer and a glove manufactured from the compositions of the present disclosure as an inner layer. Therefore, the use of a glove manufactured from the herein disclosed new class of radiation-attenuating compositions will have only minimum impact on typical surgical practice.

[00035] The compositions may comprise significant amounts of radiopaque substances, therefore offering attenuation levels superior to conventional radiation-attenuating gloves of equivalent thicknesses, without creating inherent stiffening which results in poor performance in terms of flexibility and comfort.

[00036] The radiation-attenuating compositions comprise different polymers and utilize different manufacturing processes to conventional radiation-attenuating gloves. The metal based radiation-attenuating substances do not interfere with the stability of the mixtures formulated with the polymer and the plasticizer.

[00037] In some embodiments the radiation-attenuating compositions may be organo-gels. [00038] The compositions may have a high yield- strength. By this it is meant that they have structure that will not flow or break unless exposed to very high shear stress.

[00039] In some embodiments, the yield point of the compositions is IMPa and above. By yield point it is meant the point where the composition transitions from elastic to plastic behavior, as illustrated in the stress-strain relationship in Figure 1.

[00040] In other embodiments, the yield point of the compositions is preferably 3MPa and above, or 5MPa and above, or 8MPa and above.

[00041] The compositions of the present disclosure comprise at least one structural polymer, at least one plasticizer and at least one radiopaque substance. The compositions may also comprise other additives.

Structural Polymer

[00042] The structural polymer may comprise one or more of (i) ionic or hydrophilic polymers and copolymers, such as, for example, gelatin, gums, pectin, alginates, polyureas, polyamides, peptides derivatives, starch derivatives, cellulose derivatives chosen among methyl cellulose, hydroxyethylcellulose, hydroxypropylcellulose and carboxymethylcellulose, polyethyleneimine, poly(acrylic acid), polyvinyl alcohol, polyacrylamides and their derivatives, polyvinylpyrrolidone, and thermoplastic urethane (TPU) and (ii) hydrophobic polymers and copolymers, such as, for example, fatty acid derivatives, polydimethylsiloxane, poly(vinyl ethers), poly vinyl chloride and derivatives, and Styrenic Block Copolymers (SBCs).

[00043] In some preferred embodiments, the structural polymer comprises one or more SBCs. [00044] SBCs are classified as thermoplastic elastomers, and possess the mechanical properties of rubbers and the processing characteristics of thermoplastics. These properties result from their molecular structure: SBCs consist of at least three blocks, generally two hard polystyrene end blocks and one soft, elastomeric (polybutadiene, polyisoprene - hydrogenated or not) midblock. More common SBCs comprise linear triblock copolymers such as styrene-ethylene/butylene- styrene (SEBS), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene- [ethylene-(ethylene-propylene)]-styrene (SEEPS, obtained by hydrogenation of polyisoprene/butadiene), and styrene-ethylene/propylene- styrene (SEPS), but other architectures (for example copolymers composed of more than three blocks) and other structures (star or radial) and polymer functionalization are also possible. Various architectures of SBCs can be envisaged such as star polymers with only some of the arms containing styrene. Significantly, SBCs with a saturated elastomeric mid-block offer enhanced mechanical properties and are more resistant to oxidative degradation. Plasticizer

[00045] The plasticizer may comprise one or more organic liquid materials that assist in enhancing the stretching and flexibility of the structural polymer.

[00046] For hydrophilic structural polymers, the plasticizer may comprise one or more polar materials such as, for example, water, alcohols, glycerol and glycerol derivatives, polyethylene glycols and polypropylene glycols.

[00047] For hydrophobic structural polymers, the plasticizer may comprise one or more liquid saturated polyolefins, such as, for example, those compatible with the midblock (elastomeric block) of the SBC. Exemplary plasticizers include alkyl phthalates and phosphates.

[00048] Due to their unique multi -block structure, SBCs are capable of being plasticized when a significant amount of a plasticizer for the midblock is added.

[00049] Preferred plasticizers for SBCs are mineral oils, but the plasticizer can also be sourced from “green chemistry” for example vegetable oils, such as sunflower, rapeseed, coco oil or others. The plasticizer may also be an oligomer or other elastomer that possesses sufficient compatibility with the rubbery mid-blocks of SBCs. Examples include, low molecular weight polybutadiene, polyisoprene, polyisobutene, amorphous polyolefin copolymers of propylene and ethylene, butyl rubber and other polymers known to have a sufficient compatibility with the rubbery block. The plasticizer can be a blend of molecules of different type and size.

Radiopaque substance

[00050] The radiopaque substance or substances may comprise one or more elements having an atomic number of greater than or equal to 40. The elements are preferably chosen from lead, bismuth, tungsten, barium, iodine, tin and mixtures thereof. The radiopaque substances may be in the form of metal particles, in oxide form or in salt form.

[00051] The average size of the particles of the radiopaque substance or substances may be between about 0.1 pm and about 50 pm inclusive, or between about 0.5 pm and about 20 pm inclusive, or between about 1.0 pm and about 10 pm inclusive, or between about 1.0 pm and about 5 pm inclusive.

[00052] More than one radiopaque substance can advantageously be blended to fine-tune the protection level on the full range of energy, i.e., typically from 40 to 120keV.

[00053] Preferably, radiopaque substances may comprise bismuth or tungsten or mixtures thereof. These metals offer good attenuation performance over the whole range, and especially at high energies. However, they are very expensive, more than ten times the price of lead. Replacing some of the bismuth or tungsten with barium may assist in reducing the cost, while still maintaining some protection at low levels of energy. Such “low” levels of energy (in the range 40-60kVp) can typically be observed in back-scattering radiation, considering that a part of the initial radiation energy is absorbed by the patient body.

Additives

[00054] Various other additives may be used to improve the mechanical performance of the presently disclosed compositions, such as tensile and tear resistance, up to a certain limit. Some additives can modify the morphology and the size of the phase separation of the SBC blocks. Typical additives are low molecular weight polymers miscible with the PS block, such as aromatic resins, and copolymers comprising a miscible block with the PS block such as styrene maleic anhydride resins (SMA) resins for example. Other additives may also be used to modify the film cohesion and generate tack of the SBCs composition but have limited interest for glove applications.

[00055] The presently disclosed compositions may also contain pigments, primary and secondary antioxidants, fillers (mineral or organic), crosslinking agents such as boric acid, amino acids, aldehydes, thiol, anti-static agents, anti-foam agents, biocides, surfactants, and combinations thereof.

[00056] In some embodiments the herein disclosed composition comprises:

Structural polymer: 100 parts Plasticizer: 10 to 200 parts Radiopaque substance: 200 to 600 parts Additives: 0 to 100 parts

[00057] In some preferred embodiments the herein disclosed composition comprises:

Structural polymer: 100 parts

Plasticizer: 30 to 150 parts

Radiopaque substance: 200 to 600 parts

Additives: 0 to 100 parts

[00058] In other preferred embodiments the herein disclosed composition comprises:

Structural polymer: 100 parts Plasticizer: 50 to 100 parts Radiopaque substance: 200 to 600 parts Additives: 0 to 100 parts

[00059] In other preferred embodiments the herein disclosed composition comprises:

Structural polymer: 100 parts Plasticizer: 30 to 150 parts Radiopaque substance: 250 to 500 parts Additives: 0 to 100 parts

[00060] In any of the herein disclosed embodiments the radiation attenuating composition comprises 5 to 50 parts of an aromatic resin based on styrene or substituted styrene.

[00061] In another aspect the present disclosure provides a thin film comprising one or more of the radiation attentuating compositions as herein disclosed. The thin film may have a thickness between about 10 microns and about 500 microns, preferably between about 50 microns and about 350 microns, more preferably between about 100 microns and about 300 microns.

[00062] In another aspect the present disclosure provides an article of manufacture comprising one or more of the radiation attenuating compositions as herein disclosed.

[00063] In another aspect the present disclosure provides a glove comprising one or more of the radiation attenuating compositions as herein disclosed. The glove may have a thickness between about 50 microns and about 350 microns, preferably between about 100 microns and about 300 microns.

[00064] In some embodiments the glove has an Ml 00 (modulus at 100% of the original length) of less than about 1.0 MPa, or less than about 0.80 MPa, or less than about 0.70 MPa, or less than about 0.65 MPa.

[00065] In some embodiments the glove has a thickness in the range about 0.2 to about 0.3 mm and an M100 less than about 0.70 MPa.

[00066] In another aspect there is provided a system for protecting a hand from radiation said system comprising a first glove according to any one of the herein disclosed embodiments and a second glove.

[00067] In some embodiments the second glove does not contain radiopaque metal containing particles.

[00068] In some embodiments, in use, the second glove is placed over the first glove.

[00069] The presently disclosed compositions offer the following additional advantages as compared to conventional rubbers used for radiation-attenuating gloves.

• a glove made from the herein disclosed compositions is significantly softer than any conventional radiation-attenuating glove currently on the market and offers improved radiation attenuation.

• the radiation attenuating performance measured for a given thickness is significantly improved. Typically, a 0.22 mm thick glove made from compositions according to the present disclosure exhibit similar radiation-attenuating performance to a conventional glove of a 0.30 mm thickness. • The primary indication of use of the glove is as an under-glove, in combination with a conventional surgical glove used as outer layer which offers the following additional benefits:

• there is no contact between the radiopaque particles and the patient

• the surgeon can comply with “double gloving” recommended practice, and can change the external glove as often as needed during the procedure

• the surgeon can advantageously continue to use the external glove he or she is already very familiar with (grip, dexterity,...). Therefore, the use of this new class of radiation-attenuating material will have only minimum impact on surgical practice

• the inner glove, which contain the radiopaque substances, can offer a phase contrast with the outer layer made of conventional rubber which facilitates the detection of micro-perforation in the external layer

• the inner glove composition may offer good barrier properties against passage of viruses or bacteria. Particularly compositions comprising SBCs may be cast using a solution of the SBC composition in organic solvents. The film can reach extremely high-quality requirements as the technology does not require any processing additives such as surfactants and resins that remain in the dry film. Consequently, gloves manufactured from solvent casting of SBCs show excellent barrier performance and can be advantageously used as an under-glove barrier to prevent passage of micro-organisms

• Producing a radiation-attenuating film cast from a solution in organic solvent also offers an additional important advantage compared with films cast from a dispersion (latex) of particles in water. The radiation-attenuating particles do not interfere with film formation as is the case for latexes, especially at high particle loading

[00070] Many of the herein disclosed structural polymers can form 3D visco-elastic networks by self-organisation (supramolecular chemistry), without the use of any harmful chemicals such as vulcanization accelerators used for all conventional rubbers. Therefore, the compositions of the present disclosure can offer improved skin tolerance.

[00071] This is particularly the case of SBC structural polymers, which are capable of forming elastic films with high mechanical performance without the use of any chemical cross-linking such as sulphur and accelerators, since both ends of each rubbery block are terminated by polystyrene segments and these rigid domains act as multifunctional junction points to produce a “physically” cross-linked elastomer network, similar in many respects to that of a conventional vulcanized rubber (“chemical crosslinking”). [00072] In another aspect there is provided a multilayer material comprising at least one layer comprising a radiation attenuating composition according to the present disclosure and at least one other layer. In some embodiments the other layer comprises rubber. The rubber layer may comprise natural or synthetic rubber and may be utilized to improve the glove’s mechanical properties, and allow donning without damaging the material. Preferentially, these multilayer materials should contain less than 25% of rubber (by thickness).

[00073] In another aspect the present disclosure provides a multilayered film comprising two or more layers each comprising a radiation-attenuating composition. Each layer may comprise a different radiation-attenuating composition.

[00074] Preferably, the radiation-attenuating compositions in each layer comprise a structural polymer from the same polymer family.

[00075] Preferably, the radiation-attenuating compositions in each layer comprise an SBC structural polymer.

[00076] For example, a multilayer film may comprise three layers:

- a first layer comprising SBS, plasticizer and radiopaque particles

- a second layer comprising SEBS, plasticizer and radiopaque particles

- a third layer comprising SBS, plasticizer and radiopaque particles.

[00077] As a preferred variation of this example the radiopaque composition included in the first and third layers comprises tungsten and bismuth and the radiopaque composition included in the middle (second) layer comprises lead.

[00078] This architecture offers the advantage of insulating the lead (which is toxic) between two layers of plasticized structural polymer, which minimizes the risk of contact with the wearer’s skin and the patient’s wound. This may provide a cost-effective alternative to compositions comprising only bismuth and tungsten.

[00079] In another aspect the present disclosure provides a method a making a radiation- attentuating composition comprising the step of combining, in any order, one or more structural polymers, one or more plasticizers and one or more radiopaque substances in a suitable solvent. [00080] In another aspect of the present disclosure there is provided a method of making a glove comprising the steps of combining, in any order, one or more structural polymers, one or more plasticizers and one or more radiopaque substances in a suitable solvent, dipping a suitable mold into the solution of the composition, withdrawing the mold from the solution of the composition; and drying the composition so as to provide a glove.

[00081] Further features and advantages of the present disclosure will be understood by reference to the following detailed description.

BRIEF DESCRIPTION OF THE DRAWING

[00082] Figure 1 depicts a stress-strain relationship with yield point indicated.

PET ATT ED DESCRIPTION OF THE EMBODIMENTS

[00083] The following is a detailed description of the disclosure provided to aid those skilled in the art in practicing the present disclosure. Those of ordinary skill in the art may make modifications and variations in the embodiments described herein without departing from the spirit or scope of the present disclosure.

[00084] Although any compositions, methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure, the preferred compositions, methods and materials are now described.

[00085] It must also be noted that, as used in the specification and the appended claims, the singular forms ‘a’, ‘an’ and ‘the’ include plural referents unless otherwise specified. Thus, for example, reference to a ‘SBC’ may include more than one SBCs, and the like.

[00086] Throughout this specification, use of the terms ‘comprises’ or ‘comprising’ or grammatical variations thereon shall be taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof not specifically mentioned.

[00087] Unless specifically stated or obvious from context, as used herein, the term ‘about’ is understood as within a range of normal tolerance in the art, for example within two standard deviations of the mean. ‘About’ can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear from context, all numerical values provided herein in the specification and the claim can be modified by the term ‘about’.

[00088] Any methods or processes provided herein can be combined with one or more of any of the other methods or processes provided herein.

[00089] Ranges provided herein are understood to be shorthand for all of the values within the range. For example, a range of 1 to 50 is understood to include any number, combination of numbers, or sub-range from the group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,

19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,

45, 46, 47, 48, 49, or 50.

[00090] Reference will now be made in detail to exemplary embodiments of the disclosure. While the disclosure will be described in conjunction with the exemplary embodiments, it will be understood that it is not intended to limit the disclosure to those embodiments. To the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the disclosure as defined by the appended claims.

Example 1: Preparation of gloves made of SBS structural polymer

[00091] The following example demonstrates the improved performance in relation to softness and radiation-attenuation of a composition according to one embodiment of the present disclosure. [00092] The following materials were dissolved in a mixture of methylcyclohexane and toluene (8:2) to form a solution having 17% solid content by weight.

• 100 phr of a structural Styrene-Butadiene-Styrene copolymer (SBS) with a viscosity in toluene (5% concentration) of 20 mPas at 25°C.

• 75 phr of a plasticizer of white mineral oil with a viscosity of 68 mPas at 40°C.

• 20 phr of an aromatic resin based on styrene and substituted styrenes (Mn=800 g/mol, polydispersity index = 2.8) which provides improved yield stress to the material.

• 1 phr of polyphenolic antioxidant.

[00093] Radiopaque particles (pure tungsten, particle size D50=l .5 microns) were added to the solution in an amount of 420 phr.

[00094] The mixture was stored at ambient temperature in an appropriate vessel which was covered to prevent solvent evaporation. Films were obtained following solvent evaporation after dipping a porcelain mold into the mixture using a dipping robot with controlled dipping speeds. The film was dried at 70°C for 1 hour before stripping and then a final drying at 50°C during 6 hours was performed to remove trace amounts of residual solvent.

[00095] The so-formed films were very soft and offered a sufficient yield stress.

[00096] Example 2: Preparation of gloves made of SEES structural polymer

[00097] The following example demonstrates the improved performance (softness and radiation-attenuation) of a composition according to another embodiment of the present disclosure. [00098] The following materials were dissolved in a mixture of methylcyclohexane and toluene (8:2) to form a solution having 15% solid content by weight.

• 100 phr of a structuring polymer Styrene-Ethylene/Butadiene-Styrene copolymer (SEBS) with a viscosity in toluene (5% concentration) of 12 mPas at 25°C.

• 55 phr of a plasticizer of white mineral oil with a viscosity of 68 mPas at 40°C.

• 15 phr of an aromatic resin based on styrene and substituted styrenes (Mn=800 g/mol, polydispersity index=2.8) which provides improved yield stress to the material.

• 1 phr of polyphenolic antioxidant. [00099] Radiopaque particles (tungsten carbide, particle size D50=2.4 microns) were added to the solution in an amount of 320 phr.

[000100] The mixture was stored at ambient temperature in an appropriate vessel which was covered to prevent solvent evaporation. Films were obtained following solvent evaporation after dipping a porcelain mold into the mixture using a dipping robot with controlled dipping speeds. The film was dried at 70°C for 1 hour before stripping and then a final drying at 50°C during 6 hours was performed to remove trace amounts of residual solvent.

[000101] The so-formed films were very soft and offered a sufficient yield stress.

Example 3: Radiation-attenuating performance

[000102] The purpose of testing was to evaluate the performance of gloves, formed through dipping of the compositions of Examples 1 and 2, in attenuating an X-ray beam, especially an X-ray beam within a diagnostic range of 40 kVp to 120 kVp.

[000103] In order to determine the incident intensity of the X-ray beam ( Io ), the generated X- rays were directly exposed to a DIADOS diagnostic detector connected to DIADOS diagnostic dosimeter (PTW-Freiburg, Germany) without having passed through any sample.

[000104] The distance between the X-ray tube and the detector was set to 100 cm, and the X-ray beam was well collimated at 1.5 cm ^c 1.5 cm on the sample to minimize the detection of scattered radiation.

[000105] The experiments were performed using an X-ray radiography machine (ABEX Medical System Company, Toshiba). The X-ray exposure was begun with an initial X-ray tube voltage of 40 kVp, and later with incremental increases of 20 kVp for each exposure, up to 120 kVp. The X-ray exposure was maintained at 10 mAs.

[000106] A glove sample was placed on the detector and the transmitted intensity of the X-ray beam was measured. Each measurement was repeated three times and an average determined. [000107] The X-ray attenuation (1 - T) of the samples were calculated and plotted against the X-ray tube voltages (kVp) to determine performance in attenuating the X-rays.

[000108] Table 1 contains comparative data on radiation-attenuating gloves currently in the market place (indicative data only).

[000109] Table 2 contains an evaluation of radiation-attenuating gloves made from compositions according to embodiments of the present disclosure. Ml 00 is the Modulus at 100% of the original length. It is proportional to the force required to elongate to 100% of the original length. Lower M100 values reflect a material that feels softer and more comfortable.

[000110] It may be concluded that Examples 1 and 2 are the softest gloves and offer the best attenuation performance properties when brought back to the thickness. They offer similar attenuation performance to conventional gloves of 0.30 mm thickness, but at a thickness which is 1/3 less.

[000111] The contents of all references, and published patents and patent applications cited throughout the application are hereby incorporated by reference. Those skilled in the art will recognize that the disclosure may be practiced with variations on the disclosed structures, materials, compositions and methods, and such variations are regarded as within the ambit of the disclosure. [000112] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments and methods described herein. Such equivalents are intended to be encompassed by the scope of the following claims.

[000113] It is understood that the detailed examples and embodiments described herein are given by way of example for illustrative purposes only, and are in no way considered to be limiting to the disclosure. Various modifications or changes in light thereof will be suggested to persons skilled in the art and are included within the spirit and purview of this application and are considered within the scope of the appended claims. For example, the relative quantities of the ingredients may be varied to optimize the desired effects, additional ingredients may be added, and/or similar ingredients may be substituted for one or more of the ingredients described.

Claims

1. A radiation-attenuating composition comprising:

(a) at least one structural polymer;

(b) at least one plasticizer; and

(c) at least one radiopaque substance.

2. A radiation-attenuating composition according to claim 1, wherein the structural polymer comprises one or more of (i) ionic or hydrophilic polymers and copolymers, such as, for example, gelatin, gums, pectin, alginates, polyureas, polyamides, peptides derivatives, starch derivatives, cellulose derivatives selected from methyl cellulose, hydroxy ethylcellulose, hydroxypropylcellulose and carboxymethylcellulose, polyethyleneimine, poly(acrylic acid), polyvinyl alcohol, polyacrylamides and their derivatives, polyvinylpyrrolidone, and thermoplastic urethane (TPU) and (ii) hydrophobic polymers and copolymers, such as, for example, fatty acid derivatives, polydimethylsiloxane, poly(vinyl ethers), poly (vinyl chloride) and derivatives, and Styrenic Block Copolymers (SBCs).

3. A radiation-attenuating composition according to claim 1 or claim 2, wherein the structural polymer comprises one or more SBCs.

4. A radiation-attenuating composition according to claim 2 or claim 3, wherein the one or more SBCs comprise one or more linear, radial or star SEBS, SEPS, SEEPS, SBSS, SIS, SBS and SIBS.

5. A radiation-attenuating composition according to any one of claims 1 to 4, wherein the plasticizer comprises one or more organic liquid materials that assist in enhancing the stretching and flexibility of the structural polymer.

6. A radiation-attenuating composition according to any one of claims 1 to 5, wherein the plasticizer comprises one or more polar materials such as, for example, water, alcohols, glycerol and glycerol derivatives, polyethylene glycols and polypropylene glycols.

7. A radiation-attenuating composition according to any one of claims 1 to 5, wherein the plasticizer comprises one or more liquid saturated polyolefins, such as, for example, those compatible with the midblock (elastomeric block) of the SBC.

8. A radiation-attenuating composition according to any one of claims 1 to 7, wherein the plasticizer comprises one or more mineral oils and vegetable oils, such as sunflower oil, rapeseed oil, and coco oil.

9. A radiation-attenuating composition according to any one of claims 1 to 7, wherein the plasticizer is an oligomer or other elastomer that possesses sufficient compatibility with the rubbery mid-blocks of SBCs, for example low molecular weight polybutadiene, polyisoprene, polyisobutene, amorphous polyolefin copolymers of propylene and ethylene, butyl rubber and other polymers known to have a sufficient compatibility with the rubbery block.

10. A radiation-attenuating composition according to any one of claims 1 to 9, wherein the radiopaque substance comprises one or more elements having an atomic number of greater than or equal to 40, preferably lead, bismuth, tungsten, barium, iodine, tin and mixtures thereof, in oxide form or in salt form.

11. A radiation-attenuating composition according to any one of claims 1 to 10, wherein the radiopaque substance is in the form of particles.

12. A radiation-attenuating composition according to claim 11, wherein the average particle size of the particles of the radiopaque substance is between about 0.1 pm and about 50 pm inclusive, or between about 0.5 pm and about 20 pm inclusive, or between about 1.0 pm and about 10 pm inclusive, or between about 1.0 pm and about 5 pm inclusive.

13. A radiation-attenuating composition according to any one of claims 1 to 12, wherein the radiopaque substance comprises bismuth, tungsten and mixtures thereof.

14. A radiation-attenuating composition according to any one of claims 1 to 13, wherein the radiopaque substance comprises barium.

15. A radiation-attenuating composition according to any one of claims 1 to 14, further comprising one or more additives.

16. A radiation-attenuating composition according to claim 15, wherein the one or more additives comprises one or more low molecular weight polymers miscible with a PS block, such as aromatic resins, and copolymers comprising a miscible block with a PS block such as styrene maleic anhydride resins (SMA) resins.

17. A radiation-attenuating composition according to claim 15 or 16, wherein the additive comprises one or more pigments, primary and secondary antioxidants, fillers (mineral or organic), crosslinking agents such as boric acid, amino acids, aldehydes, thiol, anti-static agents, anti-foam agents, biocides, and surfactants.

18. A radiation-attenuating composition according to any one of claims 1 to 17, comprising:

(a) structural polymer: 100 parts

(b) plasticizer: 10 to 200 parts

(c) radiopaque substance: 200 to 600 parts

(d) additives: 0 to 100 parts.

19. A radiation-attenuating composition according to any one of claims 1 to 17, comprising

(a) structural polymer: 100 parts

(b) plasticizer: 30 to 150 parts

(c) radiopaque substance: 200 to 600 parts

(d) additives: 0 to 100 parts.

20. A radiation-attenuating composition according to any one of claims 1 to 17, comprising:

(a) structural polymer: 100 parts

(b) plasticizer: 50 to 100 parts

(c) radiopaque substance: 200 to 600 parts

(d) additives: 0 to 100 parts.

21. A radiation-attenuating composition according to any one of claims 1 to 17, comprising:

(a) structural polymer: 100 parts

(b) plasticizer: 30 to 150 parts

(c) radiopaque substance: 250 to 500 parts

(d) additives: 0 to 100 parts.

22. A radiation-attenuating composition according to any one of claims 18 to 21, further comprising 5 to 50 parts of an aromatic resin based on styrene or substituted styrene.

23. A radiation-attenuating composition according to any one of claims 1 to 22, wherein the yield point of the composition is 1 MPa and above.

24. A thin film comprising one or more radiation attentuating compositions according to any one of claims 1 to 23.

25. A thin film according to claim 24, wherein the thin film has a thickness between about 10 microns and about 500 microns, preferably between about 50 microns and about 350 microns, more preferably between about 100 microns and about 300 microns.

26. An article of manufacture comprising one or more radiation attenuating compositions according to any one of claims 1 to 23.

27. A glove comprising one or more radiation attenuating compositions according to any one of claims 1 to 23.

28. A glove according to claim 27, wherein the glove has a thickness between about 50 microns and about 350 microns, preferably between about 100 microns and about 300 microns.

29. A glove, according to claim 27 or 28, wherein the glove has an M100 of less than about 0.8 MPa, or less than about 0.75 MPa, or less than about 0.70 MPa, or less than about 0.65 MPa.

30. A system for protecting a hand from radiation, said system comprising a first glove according to any one of claims 27 to 29 and a second glove.

31. A system according to claim 30, wherein the second glove does not contain radiopaque metal containing particles.

32. A system according to claim 30 or claim 31, wherein, in use, the second glove is placed over the first glove.

33. A multilayer material comprising at least one layer comprising one or more radiation attenuating compositions according to any one of claims 1 to 23 and at least one other layer.

34. A multilayer material according to claim 33, wherein the at least one other layer comprises rubber.

35. A multilayer material according to claim 34, wherein the rubber comprises natural and/or synthetic rubber.

36. A multilayer material according to claim 33, wherein the multilayer film comprises two or more layers each comprising one or more radiation-attenuating compositions according to any one of claims 1 to 23.

37. A multilayer material according to claim 36, wherein the radiation-attenuating compositions in each layer comprise one or more SBC structural polymers.

38. A multilayer material according to claim 37, wherein the multilayer material comprises three layers:

(a) a first layer comprising SBS, plasticizer and radiopaque particles

(b) a second layer comprising SEBS, plasticizer and radiopaque particles

(c) a third layer comprising SBS, plasticizer and radiopaque particles.

39. A multilayer material according to claim 38, wherein both the first and third layers comprises tungsten and/or bismuth and the second layer comprises lead.

40. A method a making a radiation-attentuating composition according to any one of claims 1 to 23, comprising the step of combining, in any order, one or more structural polymers, one or more plasticizers and one or more radiopaque substances in a solvent.

41. A method of making a glove comprising the steps of:

(a) dipping a suitable mold into a solution of the composition according to claim 40;

(b) withdrawing the mold from the solution of the composition; and

(c) drying the composition to form the glove.