GB2336099A - Multilayer glove - Google Patents

Abstract

A flexible glove 2 formed from a polyurethane based sheet, or layer, 8, and lined, in at least the portion that receives the hand, with an inner sheet, or layer, 10 of a synthetic rubber that is impermeable to water vapour. This layer prevents the vapour, released by the user's hand through sweating, from having any access to said polyurethane layer, thus preventing hydrolysis of the polyurethane, under the effect of said sweating, and giving the glove a longer lifetime. The polyurethane layer will have a thickness of between 0.2 and 0.6mm, with the rubber layer being between 0.05 and 0.2mm thick. The synthetic rubber will preferably be of the butyl rubber type, fusion bonded to the polyurethane layer. The glove may include an extended cuff, to cover part of the users forearm, and be covered in additional materials, to allow it to be adapted for use in a glove box 14.

Description

-7 %# 23360no PATENTS ACT 1977 Agents Ref. P13266GB-11/WPlmm A FLEXIBLE

AND LEAKPROOF GLOVE THE INVENTION relates to a flexible and leakproof glove, of the kind used for working in an enclosure, such as a glove box, and having the main function of protecting the user against dangerous substances or reagents that the user is to handle, or conversely for protecting the material contained inside the box from the external envirownent.

In its preferred application, the invention relates to glov es extended by flexible cuffs that flare outwards, and in which at least a portion of the forearms of the user are received, the open end of such a cuff then being arranged in conventional manner to enable it to be fixed in scaled manner to the edges of an opening formed in the front wall of the glove box.

It is known that glove boxes of this type are used in numerous fields, to handle radioactive materials or viral preparations, to mention only a few. Such gloves must then satisfy numerous conditions, in particular they must be simultaneously flexible, elastic, and have excellent mechanical properties to be suitable for withstanding risks of accidental tearing or breaking. They must also possess leakproof properties, and in particular they must be highly impermeable and highly resistant to possibly COITOSive chemicals that are present or produced in the glove box during the above-mentioned handling. Finally, they must oppose little resistance to rnovements of the hand or the fingers in order to avoid the fatigue which the user would otherwise quickly feel, thus making it desirable for the thickness of the glove to be as thin as possible.

/I- 2 There exist hardly any elastorner materials capable of satisfying all of the conditions which gloves of the kind in question need to satisfy, and indeed the enumeration above is incomplete.

That is why it has been the usual practice to have recourse to gloves made from a plurality of layers of different materials, each suitable for satisfying a respective portion of the specified conditions, it naturally being understood that the "multilayeC material itself must satisfy all of said specified conditions.

As an example of a glove of that type, mention is made of the glove described in European patent 8910825 1. 3)/03)42470 which is essentially directed to gloves for boxes or enclosures in which radioactive materials are processed.

To this end, the proprietor of that patent recommends producing gloves made of imultilayer" materials comprising, starting fi-om the inside surface of the glove that comes into contact with the hand: a first layer based on polyester urethane based on an aromatic diisocyanate; a second layer of a synthetic rubber; a third layer made of a mixture of lead oxide and polychloroprene; a fourth layer based on chlorosulfonated polyethylene; and finally another layer of polyester urethane flush with the outside surface of the glove.

As explained by the patentee, those gloves take advantage, cumulatively, of the elasticity and the good mechanical qualities of polyester urethane, the protective effect against the radioactive radiation from the materials being handled as exercised by the central layer based on lead oxide and on polychloroprene, and the properties possessed by the layer of synthetic rubber, in particular based on a non-saturated rubber based on. ethylene and propropylene, in protecting the polyester urethane layer against aggressive chemicals, including possible chemical decomposition products that might I' occur within the lead-filled central layer. The patentee does indeed also provide for the option of on-dning the last three layers when the materials to be handled are not radioactive. Under those circumstances ' it is the synthetic rubber second layer that is on the outside of the glove.

The preoccupation of providing the user with protection against the harmful effects of the substances or agents present in the glove box, or indeed against any degradation products that might form within the glove material itself can clearly be seen from that patent application, and is also constantly to be found in the state of the art. It is not surprising that the nature of the materials processed or of the sometimes corrosive atmosphere in the glove box also has the effect of reducing the lifetime of the gloves which therefore need to be replaced often.

Nevertheless, there is another factor that also contributes to the gloves having a short lifetime, in particular when the gloves take advantage of the combined qualities of flexibility, elasticity, and mechanical strength possessed by appropriate grades of polyurethane, and this factor has not previously been taken significantly into account. It is the deleterious effect on such polyurethanes, which are also sensitive to hydrolysis, of the sweat products which come from the fingers and hand of the user, and which are inevitable during prolonged use of the glove box.

Flexible grades of polyurethane do not have good resistance to hydrolysis, and as a result they lose their very good mechanical properties very quickly in the presence of water.

An object of the invention is to remedy the drawback represented by this previously disregarded factor, and to provide longer-lifetime gloves, in -1 4 particular for glove boxes, and having a basic structure made of a layer of polyurethane that is elastic, flexible, and that has high mechanical strength.

The invention relates more particularly to a flexible glove having good mechanical qualities for protecting the user from any contact with dangerous substances that may need to be handled, in which the structure suitable for imparting the desired mechanical qualities to the glove is made of a leakproof sheet or layer based on a polyurethane having the desired grade for this purpose and having a thickness of 0.2 min to 0.8 min. The glove of the invention is then characterized by associating the face of the polyurethane structure that is oriented towards the inside of the glove with an internal sheet or layer of a synthetic rubber of the butyl rubber type having a thickness of 0.05 mm to 0.2 min, that is impermeable to water vapor and that is to be interposed between the polyurethane layer and the hand of the user.

Unexpectedly, the use of this disposition has the effect of significantly lengthening the lifetime of gloves of this type that are based on polyurethane, in particular when using waterproof synthetic rubbers based on butyl rubber. The inner sheet of synthetic rubber forms a kind of preglove, so to speak, inside the glove based on polyurethane. Butyl rubber is a preferred elastomer having very good impermeability to water vapor. It protects the layer based on polyurethane fl.om hydrolysis by moisture from the sweat released by the skin of the user's hand and fingers, so that one of the major causes of the relatively rapid loss of the very good initial mechanical properties of the polyurethane based structure is eliminated. Consequently, the layer of butyl rubber serves to conserve all of the physicochemical and mechanical properties of the polyurethane layer, even during prolonged use of the glove.

Z:) 1-1 Preferably the sheet or layer of synethetic rubber is designed to come directly into contact with the hand.

Advantageously, the portion that is to receive the hand is extended by a cuff of approximately frustoconical shape in which at least a portion of the forearm of the user is received when the glove is in place in the glove box.

Conveniently, the inner sheet or layer of rubber extends essentially only over the inside surface of the portion of the glove that is to receive the user's hand, the major portion of the above-mentioned cuff then being free thereof Preferably, the synthetic rubber is of the butyl rubber type.

Advantageously, the layers of polyurethane and of impermeable synthetic rubber are intimately bonded to each other by a fusion bond.

Conveniently, the glove is also covered on its outside face by one or more layers of other materials selected as a function of the final chemical behavior required for the glove of the kind in question.

The invention also relates to a glove box defining an enclosure that is isolated from the outside and provided in its front wall with at least two openings arranged to enable them to be fixed in scaled manner to the end margins of the cuffs of a pair of gloves that are to protect the hands of the user against the materials that are to be handled in said glove box, wherein the gloves are constituted by gloves as defined above, the layer of impermeable synthetic rubber the being placed inside the glove and being isolated from the atmosphere inside said enclosure by means of the polyeruthane-based structure by the gloves.

6 Figure 1 shows very diagrammatically an embodiment of the glove (2) of the invention comprising firstly a first portion (4) adapted to receive the hand of the user, and secondly, extending the above-mentioned portion outwards, a cuff (6) that is approximately fi-ustoconical in shape, at least in its first portion. It comprises a structure or layer based on polyurethane (8) and a pre-glove (10) of impermeable synthetic rubber, in particular butyl rubber. The glove can be removably mounted via the open end of the cuff to the edges of openings provided for this purpose in the fi.ont portion (12) of a glove box (14), whose outline (16) defining the inside space of the glove box that is isolated from the atmosphere is represented symbolically by dashed lines. For the abovementioned fixing purposes, the outside edge of the glove can, for example, be provided with a rim (18), or with a rigid ring, enabling the glove to be engaged with ffiction in a groove (not shown) provided for this purpose in extra thickness formed at the edge of said opening.

Given the small thickness desired for the glove, the layer of synthetic rubber is normally designed to come into direct contact with the hand. That said, the invention does not in any way exclude said layer of synthetic rubber fl-orn being associated with any lightly porous structure for improving user comfort. Nevertheless, it will be understood that that can be done only at the cost of increasing thickness, and thus of reducing flexibility and/or elasticity of the glove, particularly for the firigers of the user.

t Indeed, it is sufficient for the "pre-glove" to occupy only the leading portion of the glove in which the hand of the user is received, thereby conserving the qualities of elasticity and flexibility of the cuff.

1 7 To produce gloves of the invention, use can be made of any production technique. For example, the gloves can be made from two-layer material, in which one layer is made of polyurethane satisfying the above-mentioned conditions and the other layer is made of butyl rubber or the like.

Nevertheless, when producing the gloves in question, it is preferable to use a technique of the "rubber solution dip" type. That technique consists in forming the glove on a mold that is dipped several times into solutions of the elastomers from which the glove is subsequently to be formed. It is preferable to use solutions of the various elastomers by implementing solvents that are compatible, in particular by operating as follows:

the mold is initially dipped in a butyl rubber solution to obtain the preglove. The length of the preglove is a function of the total length of the f-mished glove; two successive dips suffice to obtain a pre-glove having a thickness of 1/10 mm; and the mold is then dipped in a polyurethane solution; eight successive dips give a thickness of 4/10 nun.

The glove as finally obtained is in a single piece because the various layers from which it is formed are indissociable. It will be understood that it is easy in this method to form a pre-glove of shoil length occupying that region of the final glove that is to receive the hand, and in particular the fingers of the user (by modifying the relative dipping "depths").

By using molds of different sizes and different lengths, it is naturally possible to obtain as many models of glove as may be desired.

That said, it can also be appropriate to protect the outside surface of the glove as well (from contact with the atmosphere inside the glove box) by one or 8 more additional layers of material, depending on the nature of the materials to be processed withmi the glove box. Polyurethanes do not generally have very good resistance to chemicals. By way of example, the polyurethane glove can be protected from external chemical attack by one or more outer coatings of synthetic rubbers selected specifically as a function of the desired chemical behavior. This can be a polychloroprene, a chlorosulfonated polyethylene, a rubber based on ethylene and propropylene known under the initials EP13M, or a fluoroelastomer.

This outer layer (or these outer layers) could likewise be produced by the above-mentioned rubber solution dip technique on the same mold after the inner pre-glove of impermeable synthetic rubber and then the polyurethane glove have been formed in succession thereon. Where necessary, the outer layer could be made antistatic by a layer of antistatic polyurethane or by another synthetic rubber, depending on the specific chemical behavior desired by the user of the final glove.

By way of example, the characteristics of a glove of the invention are given below.

100% modulus: 2AMPa 0. 2 MPa (Standard NF T46 002) Breaking strength: 60 MPa 5MPa (Standard NF T46 002) Breaking elongation: 700% = MPa (Standard NF T46 002) Tear strength: 24N = 3N ( Standard EN NF 388) Puncture Strength: 55N -- 5N ( Standard EN NF 388) To sum up, the glove of the invention is a glove of polyurethane that is very flexible and that has very good mechanical properties, with the mechanical characteristics thereof being protected on the inside by a pre- glove, preferably 1 9 of butyl rubber, and where necessary on the outside by layers of Clastorner selected depending on the nature of the materials that the user is going to handle, and where appropriate, on the basis of the atmosphere that may then be present in the glove box.

Finally, the invention relates to glove boxes per se when fitted with gloves of the type described above. The invention thus relates particularly to a glove box defining an enclosure that is isolated from the outside, provided in its front wall with at least two openings arranged to be suitable for fixing in sealed manner to the margins at the ends of a pair of gloves for protecting the hands of the user against the materials that are to be handled in the glove box, said gloves then having the characteristics of the invention as specified above and the layer of impermeable synthetic rubber then being placed inside the glove and being isolated ftom the atmosphere inside said enclosure by the polyurethane based structure of the gloves.

Claims (11)

1. A flexible glove having good mechanical qualities for handling substances that require the user to be protected from any contact with the substances, the structure of the glove being suitable for giving it the desired mechanical qualities is made of a polyurethane-based leakproof sheet or layer having a thickness of 0. 2 min to 0. 8 nun and, at least 'm the portion of the glove that is to receive the hand, by the face of the polyurethane structure that is directed towards the inside of the glove is associated with an inner sheet or layer of a synthetic rubber of the butyl rubber type that has small thickness lying in the range 0.05 mm to 0.2 mm, that is impermeable to water vapor, that is to be interposed between the polyurethane layer and the hand of the user, and that is consequently to prevent vapoi- released by the user's hand sweating having any access to said polyui-ethane layer, and thus to prevent the polyurethane layer losing its mechanical and physico-chemical properties.

2. A glove according to claim 1, characterized in that the sheet or layer of synthetic rubber is designed to come dii-ectly into contact with the hand.

A glove according to claim 1 oi- claim 2, in which the portion that is to receive the hand is extended by a cuff of approximately frustoconical shape in which at least a portion of the forearm of the user is received when the glove is in place in the glove box.

4. A glove according to clalim '), characterized in that the inner sheet or layer of rubber extends essentially only, over the inside suiface of the portion of the glove that is to receive the usei.'s hand, the major portion of the abovementioned cuff then being fi-ee thereof 1 1 11

5. A glove according to any one of claims 1 to 4, characterized in that the synthetic rubber is of the butyl rubber type.

6. A glove according to any one of claims 1 to 5, characterized in that the layers of polyurethane and of impermeable synthetic rubber are intimately bonded to each other by a fusion bond.

7. A glove according to any one of claims 1 to 6, characterized in that it is also covered on its outside face by one or more layers of other materials selected as a function of the final chemical behavior required for the glove of the kind in question.

8. A glove box defining an enclosure that is isolated from the outside and provided in its fl-ont wall with at least two openings arranged to. enable them to be fixed in sealed manner to the end margins of the cuffs of a pair of gloves that are to protect the hands of the user against the materials that are to be handled in said glove box, characterized in that the gloves are constituted by gloves according to any one of claims 1 to 7, the layer of impermeable synthetic rubber then being placed inside the glove and being isolated from the atmosphere inside said enclosure by means of the polyurethane-based structure of the gloves.

9. A flexible glove substantially as hereInbefore described with reference to and as shown in the accompanying drawing.

10. A glove box substantially as hereinbefore described with reference to the accompanying drawing.

11. Any novel feature or combination of features disclosed herein.