Glove having high mechanical performance, with high resistance to chemical products and/or radiolysis, and method for making same

Abstract

The invention concerns a glove having high mechanical performance, and high resistance to chemical products and/or radiolysis, characterised in that it comprises one or several elastomer layers, identical or different, obtained from solutions of said elastomers in one or several organic solvents or in water, said layers being reinforced, on one or several parts or on the entire internal surface of the glove, with a fabric with high mechanical strength. The invention also concerns a method for making said glove and its uses.

Description

[0001] The present invention relates to a glove exhibiting high mechanical performance together with high chemical and radiolytic resistance, and to a process for manufacturing such a glove.

[0002] For applications in the nuclear industry, various types of gloves have been described.

[0003] In particular, patent U.S. Pat. No. 5,165,114 in the name of Siemens A G, discloses gloves especially adapted for being mounted on glove boxes containing radioactive material. These gloves are formed from a superposition, from the internal face of the glove toward the external face, of a layer of polyurethane, a layer of rubber (such as a chlorosulfonated polyethylene or an ethylene-propylene copolymer), a layer formed from a mixture of lead oxide and polychloroprene, for radioactivity protection) and then, again, a layer of rubber and a layer of polyurethane, the rubber layers preventing the polyurethane from reacting with the lead oxide. These gloves, although they are suitable for protection against radioactive radiation, do not have satisfactory mechanical properties.

[0004] Moreover, patent application FR 2 777 163 in the name of Piercan S A discloses gloves comprising a layer of rubber (for example a butyl rubber), designed to come into contact with one's hand, and a layer of polyurethane. The latter provides the glove with mechanical strength, while the rubber layer present on the internal face of the glove prevents hydrolysis of the polyurethane when in contact with the user's hand. Such gloves can be used in glove boxes, especially for handling radioactive substances. They have a tear strength of 24 N and a puncture strength of 55 N according to the NF EN 388 Standard.

[0005] However, the gloves suitable for handling radioactive substances described above do not exhibit sufficient mechanical performance. In particular, their puncture strength and tear strength do not provide the user with optimum protection.

[0006] On the other hand, gloves providing high protection against the risks of cutting have been disclosed in patent EP 0 716 817 in the name of Hutchinson. These gloves comprise, on that face of the glove that is intended to cover the palm of the hand, a material of high cut resistance (such as a knit of para-aramid fibers), while that face of the glove intended to cover the back of the hand is formed by an elastic fabric of natural or synthetic organic fibers (such as a cotton fiber knit). On all or part of its external surface, the glove may also be coated with an elastomer by successive dipping of the glove into an aqueous dispersion of said elastomer, so as to make the fibers described above impermeable to certain agents, such as oils or aqueous substances, and to prevent the premature wear or deterioration of these fibers when objects with asperities are being handled.

[0007] To protect the user's hands effectively, it would be desirable to use elastomers that, apart from their role of making the fabric impermeable and protected from the external environment, exhibit good mechanical properties, especially from the standpoint of puncture strength and tear strength. In this regard, it would be more advantageous to use elastomers derived from solutions, which may have better mechanical properties than when they are derived from aqueous dispersions (for example in the case of certain polyurethanes). Moreover, certain elastomers can be employed only in the form of solutions and are therefore not available in the form of aqueous dispersions, as is the case for example with butyl rubbers.

[0008] Now, patent EP 0 716 817 discloses the coating of a fabric only with elastomers in the form of aqueous dispersions, by successive dipping of the fabric into these aqueous dispersions. As those skilled in the art know, dipping a fabric directly into an elastomer solution is in fact precluded, since it would entail, on account of the high penetration power of elastomer solutions, complete inclusion of the fabric, over its entire thickness) in the elastomer. This would result in a loss of flexibility of the fabric. The gloves thus obtained would be particularly uncomfortable for the user to wear, their lack of pliancy making them unsuitable for following the hand and finger movements.

[0009] Likewise, U.S. Pat. No. 4,742,578 discloses surgical gloves formed from a layer of a synthetic rubber latex to which a fabric coating is adhesively bonded. The manufacture of these gloves is carried out in two steps:

[0010] 1) dipping a mold in a latex, followed by drying and vulcanizing; and then

[0011] 2) adhesively bonding the pieces of fabric to the sensitive parts.

[0012] The glove thus obtained may again be dipped in a latex. It may also be turned inside out. The mechanical strength and chemical resistance of these gloves are insufficient. Furthermore, the resistance to radioactive radiation is neither mentioned nor suggested in that document.

[0013] Finally, U.S. Pat. No. 5,259,069 discloses surgical gloves formed from an internal glove made of an elastic material, this internal glove being covered with a second glove made of an elastic material sealed in places to the internal glove, pieces of fabric being placed between the two elastic gloves, these pieces of fabric being capable of moving between the two gloves. The document teaches the preparation of the gloves by dipping a mold in a latex bath. These gloves exhibit insufficient chemical resistance and mechanical strength and resistance to radioactive radiation is neither mentioned nor suggested in that document.

[0014] In the light of the drawbacks of the gloves disclosed in the prior art, the object of the invention is to provide a glove that exhibits high mechanical performance, in particular as regards puncture strength and tear strength, while still being suitable for handling radioactive substances and/or chemicals.

[0015] These objectives are achieved by combining a high-strength fabric layer with one or more layers of elastomers selected for their high chemical resistance and/or their radiolytic resistance. What are used for this purpose are, surprisingly, elastomers in the form of solutions in one or more organic solvents or in water, these being types of elastomers that those skilled in the art did not know, hitherto, how to combine with a fabric.

[0016] The subject of the invention is therefore a glove exhibiting high mechanical performance together with high chemical and/or radiolytic resistance, characterized in that it comprises:

[0017] one or more layers of elastomers, which are identical or different, are obtained from solutions of said elastomers in one or more organic solvents or in water,

[0018] these layers being reinforced, over one or more parts or over all of the internal surface of the glove, by a high-strength fabric.

[0019] Within the context of the present invention, the term “radiolytically resistant glove” is understood to mean a glove in which no degradation due to the action of radioactive radiation, namely no appearance of cracking in the structure of the glove, is detectable visually after several months of use (at least after 3 months, advantageously after 12 to 36 months or more).

[0020] The term “chemically resistant glove” is understood to mean a glove that allows the handling of substances with which the user must avoid any contact, for example substances that attack the skin or those with which contact is dangerous (viral preparations, corrosive chemicals, for example).

[0021] The term “elastomer solution” is understood to mean an elastomer in liquid form present as a single continuous phase, as opposed to an aqueous elastomer dispersion (or latex).

[0022] The term “internal surface of the glove” is understood to mean that surface of the glove intended to come into contact with the user's hand.

[0023] The term “high-strength fabric” is understood to mean a fabric having a high puncture strength and a high tear strength, these being determined according to the NF EN 388 Standard. As regards the level of cut resistance, this depends on the nature of the fabric chosen, on the diameter of the fibers and on the mesh size of the fabric, if the fibers of the fabric are knitted.

[0024] According to the NF EN 388 Standard, the levels of puncture strength, cut resistance and tear strength involve different mechanical properties, since they correspond to the resistance to mechanical stresses of various types, namely resistance to contact with a sharp object, resistance to contact with a cutting object, and the ability of a specimen with a notch not to tear further from this notch, respectively.

[0025] In the glove according to the invention, said high-strength fabric advantageously consists of woven or knitted, natural or synthetic fibers selected from fibers of high-tenacity polyethylene, high-tenacity polyester, polyaramid (such as KEVLAR®), polyamide, viscose and blend thereof.

[0026] The elastomers themselves may be selected from the group formed by polyurethanes, chlorosulfonated polyethylenes (for example the product sold under the brand name HYPALON® by DuPont de Nemours, France), polychloroprenes (for example the product sold under the brand name NEOPRENE® by DuPont de Nemours, France), butyl rubbers, synthetic or natural polyisoprenes, polyvinyl alcohols and blends thereof.

[0027] However, these examples are not limiting: in general, any elastomer that can be dissolved in an organic solvent or in water and capable of forming a film after evaporation of the solvent could be used.

[0028] The fact of using elastomers in the form of solutions advantageously makes it possible to select elastomers that have better mechanical properties than if they were derived from aqueous dispersions (in the case of certain polyurethanes for example), or of using elastomers belonging to the same chemical family but having different structures than those existing in the form of aqueous dispersions (for example in the case of polychloroprenes). Moreover, certain elastomers are not available in the form of aqueous dispersions, but can be employed only in the form of solutions, for example in the case of butyl rubbers.

[0029] Depending on the nature of the elastomer chosen, the glove according to the invention may exhibit, in addition to high mechanical performance, a high chemical and/or radiolytic resistance. To give examples from elastomers mentioned above, the use of polyurethanes, chlorosulfonated polyethylenes and polychloroprenes allows a radiolytically resistant glove to be obtained. Chlorosulfonated polyethylenes, polyvinyl alcohols and polyisoprenes (including natural rubber) also give the glove according to the invention excellent chemical resistance to liquids (water, oils, solvents). If chemical resistance to gases is desired, the use of butyl rubbers is then recommended.

[0030] In one advantageous embodiment of the glove according to the invention, this comprises:

[0031] one or more layers of polyurethane, obtained from a solution of said polyurethane in one or more organic solvents,

[0032] these layers being reinforced, over one or more parts or over all of the internal surface of the glove, by a high-strength fabric.

[0033] Preferably, said polyurethane solution includes at least one polar solvent.

[0034] Such a glove is resistant to radiolysis and therefore can be used in a radioactive environment.

[0035] In the gloves according to the invention, the total thickness of the elastomer layers is preferably between 0.3 and 1 mm.

[0036] The gloves according to the invention, whatever the nature of the elastomeric layers, advantageously have a puncture strength of at least 150 N and a trouser tear strength of at least 75 N, these being measured according to the NF EN 388 Standard (i.e., according to this standard, level 4 puncture and trouser tear strength).

[0037] The gloves according to the invention also exhibit excellent resistance to thermal aging and are completely impermeable, within the meaning of the NF EN 374-2 Standard.

[0038] The subject of the present invention is also a process for manufacturing a glove as defined above, characterized in that it comprises the following steps:

[0039] a) dipping of a mold, at least once, into one or more identical or different solutions of one or more elastomers in one or more organic solvents or in water;

[0040] b) application, to one or more parts or to all of the surface of said elastomer layers, as obtained from the previous step, of a high-strength fabric; and then

[0041] c) removal of the glove by turning it inside out.

[0042] In this process, the organic solvents and the high-strength fabric are as defined above in relation to the glove according to the invention.

[0043] Depending on the desired final thickness of the elastomer layers, step a) of dipping the mold in elastomer solutions may be repeated up to 20 times, for example 6 to 20 times. In which case, each elastomer layer is dried, at least partly, before the mold is dipped again into an elastomer solution.

[0044] The process according to the invention may include, prior to step b), a step a′) of drying each elastomer layer obtained on said mold during step a).

[0045] According to one advantageous method of implementing the process according to the invention, said high-strength fabric layer applied during step b) is pre-impregnated with water optionally containing a nonionic surfactant, or with at least one solvent for the elastomer that is directly in contact with said fabric layer.

[0046] As a variant, the process according to the invention may include, between steps b) and c), a step b′) of impregnating the high-strength fabric layer with at least one solvent for the elastomer that is directly in contact with said fabric layer.

[0047] The impregnation of the fabric by the solvent may, for example, be carried out by applying the solvent to the fabric layer by brushing or by spraying. This impregnation may also be carried out by immersing, in at least one solvent for said elastomer:

[0048] either the mold/elastomer/high-strength fabric assembly, if the impregnation of the fabric with a solvent is carried out between steps b) and c);

[0049] or the fabric alone, if the impregnation of the fabric with a solvent is carried out prior to step b).

[0050] The solvent used to impregnate the fabric allows the latter to be bonded to the elastomer layers: this is because it enables the surface of the elastomer in contact with the fabric to be partially dissolved, resulting in adhesion at the interface between the elastomer and the fabric.

[0051] The process according to the invention preferably includes, immediately before step c) of removing the glove by turning it inside out, a step c′) of drying the mold/elastomer/high-strength fabric assembly.

[0052] In the light of the various features of the process according to the invention, as described above, this may therefore comprise the succession of following steps:

[0053] a) dipping of a mold, at least once, in one or more identical or different solutions of one or more elastomers in one or more organic solvents or in water;

[0054] a′) drying of each elastomer layer obtained on the mold during step a);

[0055] b) application, to one or more parts or to all of the surface of said elastomer layers, as obtained after the previous step, of a high-strength fabric layer, said fabric possibly be imbibed with water optionally containing a nonionic surfactant;

[0056] b′) impregnation of the high-strength fabric layer with at least one solvent for the elastomer that is directly in contact with said fabric layer;

[0057] c′) drying of the mold/elastomer/high-strength fabric assembly obtained after the previous step; and then

[0058] c) removal of the glove by turning it inside out.

[0059] The process according to the invention may also comprise the succession of following steps:

[0060] a) dipping of a mold, at least once, in one or more identical or different solutions of one or more elastomers in one or more organic solvents or in water;

[0061] a′) drying of each elastomer layer obtained on the mold during step a);

[0062] b) application, to one or more parts or to all of the surface of said elastomer layers, as obtained after the previous step, of a high-strength fabric layer, this fabric being impregnated with at least one solvent for the elastomer that is directly in contact with said fabric layer;

[0063] c′) drying of the mold/elastomer/high-strength fabric assembly obtained after the previous step; and then

[0064] c) removal of the glove by turning it inside out.

[0065] The elastomers employed in the process according to the invention may be selected from the group formed by polyurethanes, chlorosulfonated polyethylenes, polychloroprenes, butyl rubbers, synthetic or natural polyisoprenes, polyvinyl alcohols and blends thereof.

[0066] The process according to the invention makes it possible to reinforce, by means of a fabric, one or more layers of elastomers deriving from solutions of said elastomers in an organic solvent or in water. Such a process palliates the shortcomings of the glove manufacturing processes known hitherto.

[0067] This is because, no method allowing a layer of elastomer deriving from a solution of said elastomer in an organic solvent or in water to be reinforced with a fabric, and to do so without coating all of the fibers of the fabric (thereby resulting in a loss of pliancy of the fabric) has been described in the prior art: the methods proposed consist in imbibing a fabric, placed on a mold of the desired shape, with a coagulating solution and then in dipping the fabric in an aqueous elastomer dispersion, which will coagulate on the surface of the fabric without penetrating throughout its thickness, as described for example in patent EP 0 716 817. A step of removing the coagulating solution is then necessary before the glove is vulcanized and extracted from the mold.

[0068] Other methods, which consist in manufacturing the glove “inside out”, that is to say in forming the elastomer layers and then in making a fabric adhere to their surface using an adhesive or a lubricating agent, also require the use of elastomers in aqueous dispersions, as disclosed in patent U.S. Pat. No. 4,283,244.

[0069] Particularly advantageously, the process according to the invention therefore makes it possible to produce, by the dipping technique, gloves comprising layers of elastomers deriving from solutions of said elastomers, the layers being reinforced with a fabric layer. The novel succession of steps in the process according to the invention allows limited interpenetration between the elastomer and the fabric when these two materials are brought into contact with each other during step b) of the process. The elastomer only partly penetrates the thickness of the high-strength fabric layer, preventing all of the meshes of the fabric being coated with the elastomer. The fabric therefore remains pliant and retains its mechanical properties. This makes it possible to obtain a glove that is very pliant and comfortable to wear, properties that are essential for the user to be able to carry out meticulous tasks while maintaining very accurate movements.

[0070] In particular, it should be noted that according to the invention it is possible to manufacture gloves without any adhesive-type product being involved in fastening the fabric to the elastomer. This is a major advantage if the glove is used for handling radioactive substances, since adhesive-type products are generally sensitive to radiolysis. When a glove is formed from a fabric and an elastomer that are joined together by means of an adhesive, degradation of the adhesive by radiolysis is likely to make the glove lose its protective properties.

[0071] Furthermore, the gloves according to the invention make it possible for one's hand to be completely protected and have a pliancy allowing one's hand to maintain all its dexterity when handling objects.

[0072] The subject of the invention is also the use of the glove as defined above for handling radioactive substances or dangerous chemicals, such as corrosive chemicals or biological material.

[0073] The subject of the invention is also a glove box, that is to say a sealed enclosure for handling products that have to be isolated from the external environment, or products with which the user or the handler must not be in contact, characterized in that it comprises at least one glove as defined above.

[0074] Apart from the above provisions, the invention also comprises other provisions that will become apparent from the following description, which refers to detailed examples of the manufacture of gloves according to the invention. However, it should of course be understood that these examples are given merely to illustrate the subject matter of the invention, these in no way representing a limitation thereof.

EXAMPLE

Manufacture of a Radiolytically Resistant Glove According to the Invention

[0075] A glove according to the invention, comprising a polyurethane layer reinforced with a fabric layer, namely DYNEEMA® (a high-tenacity polyethylene fabric sold by DSM), was obtained by the process described below.

[0076] Firstly, a step of dipping a mold, having the shape and dimensions of a hand, in a solution of polyurethane in an organic solvent, such as N,N-dimethylacetamide, dimethylformamide or tetrahydrofuran, or in a blend of several organic solvents, was carried out.

[0077] Any polyurethane known to those skilled in the art that can be dissolved in an organic solution and capable of forming a film after evaporation of the solvent could be used. As examples, mention may be made of a polyurethane of the aromatic or aliphatic, polyester or polyether type. However, these examples are not limiting and, apart from the solubility characteristics and the film-forming properties described above, any polyurethane having a modulus at 20% elongation of less than 3 MPa, a modulus at 100% elongation of less than 7 MPa, a tensile strength of greater than 20 MPa and an elongation at break of greater than 400% could be used.

[0078] As for the mold, this may conventionally be made of ceramic or metal.

[0079] The dipping of the mold in the polyurethane solution was repeated 6 to 20 times, each polyurethane layer obtained on the mold being partially dried, for example in an oven at a temperature of between 20 and 130° C., preferably 60° C., for a time of between 1 and 300 minutes, preferably 60 minutes, before again dipping the mold in the polyurethane solution. The temperatures and times indicated here depend on the solvent used and on the type of polyurethane used.

[0080] During each dipping operation, the mold was held for between 30 and 30 minutes, preferably 10 minutes, in the polyurethane solution.

[0081] The polyurethane layer thus obtained on the mold, after the latter had been dipped one or more times in the polyurethane solution, was then completely dried, for example in an oven at a temperature of between 20 and 130° C. (preferably 80° C.) and for a time between 2 and 24 hours (preferably for 5 hours), the temperature and the time both being chosen depending on the solvent used and on the type of polyurethane used.

[0082] A high-strength fabric, in this case DYNEEMA®, was imbibed with water, the water optionally containing up to 50% of a nonionic, for example ethoxylated, surfactant. This fabric was applied to one or more parts or to all of the surface of the polyurethane layer as obtained above, the application of the fabric to the polyurethane being facilitated by the presence of water in the fabric and possibly by the presence of the surfactant.

[0083] It is possible, for example, to apply the fabric only to that part of the polyurethane layer corresponding to the user's hand, without covering that part of the polyurethane layer corresponding to the user's forearm. It is also possible to apply the fabric in a number of regions well-defined on the polyurethane layer, for example in the region corresponding to the internal face of the hand, in the region of the palm of the hand and along regions corresponding to the fingers of the user.

[0084] A solvent for said polyurethane was then applied in contact with the DYNEEMA® layer, for example by immersing the mold/polyurethane/high-strength fabric assembly in at least one solvent for said polyurethane (such as N,N-dimethylacetamide, dimethylformamide or tetrahydrofuran).

[0085] Drying the mold/polyurethane/high-strength fabric assembly obtained above at a temperature of between 20 and 100° C. (preferably 70° C.) allowed the fabric to adhere to the polyurethane at the interface between these two materials. The solvent for the polyurethane applied in contact with the DYNEEMA® layer in fact causes the surface of this elastomer to be partially dissolved, which thus becomes capable of adhering to the fabric, the fabric and polyurethane layers adhering intimately to each other after complete evaporation of the solvent.

[0086] Finally, the glove was removed from the mold by simply turning it inside out. A glove resistant to radiolysis for at least 24 months was obtained.

[0087] In the example of manufacture of a radiolytically resistant glove that has just been described above, it would also be possible to dip the mold firstly in a solution of an elastomer chosen for its chemical resistance properties, using the same protocol as that described above in relation to polyurethane, and then to dip the mold in a solution of polyurethane or of another radiolytically resistant elastomer, before applying a high-strength fabric to the polyurethane layer. Thus, a glove according to the invention comprising two different elastomer layers, which glove is both radiolytically and chemically resistant, would be obtained.

[0088] As is apparent from the foregoing, the invention is in no way limited to those of its methods of implementation, its embodiments or applications that have been more explicitly described; on the contrary, it encompasses all variants that may fall within the competence of a person skilled in the art, without thereby departing either from the context or the scope of the present invention.

Claims

1. A glove exhibiting high mechanical performance together with high chemical and/or radiolytic resistance, characterized in that it comprises:

one or more layers of elastomers, which are identical or different, obtained from solutions of said elastomers in one or more organic solvents or in water,

these layers being reinforced, over one or more parts or over all of the internal surface of the glove, by a high-strength fabric.

2. The glove as claimed in claim 1, characterized in that the elastomer or elastomers are in the form of a solution in one or more organic solvents or in water, present as single continuous phase.

3. The glove as claimed in claim 1 or claim 2, characterized in that it includes, on that surface of the glove which is intended to come into contact with the user's hand, a high-strength fabric.

4. The glove as claimed in any one of claims 1 to 3, characterized in that said high-strength fabric consists of woven or knitted, natural or synthetic fibers selected from fibers of high-tenacity polyethylene, high-tenacity polyester, polyaramid, polyamide, viscose and blends thereof.

5. The glove as claimed in any one of claims 1 to 4, characterized in that said elastomers are selected from the group formed by polyurethanes, chlorosulfonated polyethylenes, polychloroprenes, butyl rubbers, synthetic or natural polyisoprenes, polyvinyl alcohols and blends thereof.

6. The glove as claimed in any one of the preceding claims 1 to 5, characterized in that it comprises:

one or more layers of polyurethane, obtained from a solution of said polyurethane in one or more organic solvents,

these layers being reinforced, over one or more parts or over all of the internal surface of the glove, by a high-strength fabric.

7. The glove as claimed in any one of the preceding claims 1 to 6, characterized in that the total thickness of the elastomer layers is between 0.3 and 1 mm.

8. The glove as claimed in any one of the preceding claims 1 to 7, characterized in that it has a puncture strength of at least 150 N.

9. The glove as claimed in any one of the preceding claims 1 to 8, characterized in that it has a trouser tear strength of at least 75 N.

10. A process for manufacturing the glove as defined in any one of the preceding claims 1 to 9, characterized in that it comprises the following steps:

a) dipping of a mold, at least once, into one or more identical or different solutions of one or more elastomers in one or more organic solvents or in water;

b) application, to one or more parts or to all of the surface of said elastomer layers, as obtained from the previous step, of a high-strength fabric layer and then

c) removal of the glove by turning it inside out.

11. The process as claimed in claim 10, characterized in that no adhesive-type product is involved in fastening the fabric to the elastomer.

12. The process as claimed in claim 10 or claim 11, characterized in that it includes, prior to step b), a step a′) of drying each elastomer layer obtained on said mold during step a).

13. The process as claimed in any one of claims 10 to 12, characterized in that said high-strength fabric layer applied during step b) is pre-impregnated with water optionally containing a nonionic surfactant, or with at least one solvent for the elastomer that is directly in contact with said fabric layer.

14. The process as claimed in any one of claims 10 to 13, characterized in that it includes, between steps b) and c), a step b′) of impregnating the high-strength fabric layer with at least one solvent for the elastomer that is directly in contact with said fabric layer.

15. The process as claimed in any one of claims 10 to 14, characterized in that it includes, immediately before step c) of removing the glove by turning it inside out, a step of drying the mold/elastomer/high-strength fabric assembly.

16. The process as claimed in any one of claims 10 to 15, characterized in that said elastomers are selected from the group formed by polyurethanes, chlorosulfonated polyethylenes, polychloroprenes, butyl rubbers, synthetic or natural polyisoprenes, polyvinyl alcohols and blends thereof.

17. The use of the glove as claimed in any one of claims 1 to 9 for handling radioactive materials.

18. The use of the glove as claimed in any one of claims 1 to 9 for handling dangerous chemicals, such as corrosive chemicals, or biological material.

19. A glove box, characterized in that it comprises at least one glove as defined in any one of claims 1 to 9.