WO1998018857A1

WO1998018857A1 - Light incompressible elastomeric material and article providing comfort (anti-eschar) and/or protection when applied

Info

Publication number: WO1998018857A1
Application number: PCT/FR1997/001956
Authority: WO
Inventors: Guy Bardot
Original assignee: Guy Bardot
Priority date: 1996-10-31
Filing date: 1997-10-31
Publication date: 1998-05-07
Also published as: AU4953897A; FR2755139A1; FR2755139B1

Abstract

The present invention relates to a material to be used notably in the manufacture of articles improving the comfort and/or protection of persons at the solid-solid interface with their contact environment, and containing an elastomer gel complete with: - a deformable and incompressible non-thermoplastic elastomer gel, - and a filler included in the gel, comprised of particles of which density is the same as or lower than that of the gel. Said particles are hollow glass beads of a density comprised between 0.10 and 0.14. This material is particularly suitable for the manufacture of articles useful in the preventive therapy of eschars (cushions, mattresses). The invention is also intended for use in these anti-eschar articles and other articles of comfort and protection employing said material. The manufacturing process for this material constitutes another aim of the invention.

Description

INCOMPRESSIBLE LIGHTWEIGHT ELASTOMERIC MATERIAL AND COMFORT ARTICLE (ANTI-SINKS) AND / OR PROTECTION USING THE SAME

TECHNICAL AREA :

The field of the present invention is that of materials whose mechanical properties can be exploited to improve the comfort and / or the protection of individuals at the solid / solid interfaces with their contact environment.

STATE OF THE ART:

The three most common positions for people are standing, sitting and lying down. In each of these positions, there are necessarily parts of the body arranged at the solid / solid interface of contact with the environment. Depending on whether one is standing, sitting or lying, this contact environment is, e. g., respectively the floor, a seat and a bed.

To improve the comfort at these interfaces, we can have recourse to articles, such as:

- shoe soles in terms of standing,

- seat cushions for the seating position,

- and mattresses for the reclining station.

The problem of comfort at the solid / solid interface, when sitting or lying down, is more acute than for standing, due to the fact that the immobility, which characterizes these first two stations, is at origin of pathologies due to prolonged compressions of the tissues at the level of the bony protrusions (ischemia) leading to necrosis called "bedsores".

It is therefore particularly important to use materials of appropriate quality at the level of these solid / solid interfaces, in particular in a lying and sitting station. Provided that they have damping properties, such materials can also find their utility in other solid / solid interfaces of individuals, for protection purposes, in particular against shocks. It is therefore, in this case, instantaneous stresses. The present invention fits into this context and it relates to a material capable of being used, in particular, for the manufacture of articles improving the comfort and / or the protection of individuals at the solid / solid interface with their contact environment. , this material being of the type of those comprising an elastomeric gel. The invention also relates to certain specific arrangements for manufacturing such a material.

The invention finally encompasses comfort and / or protection articles, in particular anti-decubitus cushions and / or mattresses, made from the above material. In the prior art, there are various proposals, unfortunately unsuccessful, relating to so-called "static" interfaces, that is to say intended for solid / solid contact areas in prone and seated positions.

Thus known compressible synthetic foam materials which do not provide satisfaction in terms of comfort and / or protection at the solid / solid interface and even less for the resolution of the problem of bedsores.

By way of illustration of this type of earlier proposal, mention may be made of patent application FR 2 676 360, which relates to anti-decubitus mattresses and cushions for medical use, constituted by a neoprene envelope with air bubbles, containing a polyurethane synthetic foam or any other "foamable" synthetic material. The space between the polyurethane foam and the neoprene cover is occupied by a synthetic gel, for example a polyurethane, a polysiloxane or the like. It is specified in this patent application that, in order to reduce the weight, it is possible to manufacture the cushions without gel between the cover and the foam. The compressible nature of this type of foam material is particularly disadvantageous, because it does not prevent wrinkling of the skin for the user subject, at the level of contact with the comfort article, for example the cushion made from this material. However, such dermal folds induce tissue shearing forces, which is conducive to the appearance of bedsores.

Water cushions or mattresses have also been proposed as a solid / solid static interface. These articles have two major drawbacks: they are heavy and they are very cold on the skin (23 ° C for a skin temperature of 37 ° C).

Gases, such as air, have been substituted for water in this type of solid / solid interface (cushions, mattresses). The gain in lightness thus obtained is far from compensating for the structural defect of these articles, which is to deflate if they are not kept under pressure by an autonomous compressor. It is easy to see that this type of equipment is somewhat prohibitive in terms of cost and noise pollution.

Furthermore, European patent application EP 0 421 540 is known which discloses a cushion capable of equalizing the pressure and consisting of an envelope filled with a large number of loose cubic parts, the latter being formed by a deformable foam. Each of these pieces is itself wrapped in a low friction material, such as nylon fabric. Such a structure does not seem likely to give satisfactory results in the prophylactic treatment of pressure sores. The option which seems to be retained at present, for lack of anything better, is that of the solid / solid interfaces made of compact, dense, therefore very heavy polyurethane gel. In addition to this excess weight, such materials have the drawback of imperfectly matching the shape of the body parts concerned and of not making it possible to avoid wrinkling of the skin, and therefore subsequent bedsores. It is not an optimal solution from the comfort point of view.

Patent application FR 2 636524 relates to cushions, anti-decubitus mattresses for medical use, constituted by an envelope of neoprene with air bubbles, filled with a gel or, more precisely, a retractable polyurethane resin. The air bubbles in the neoprene shell are said to provide relief which, in all likelihood, remains insufficient.

In addition, the polyurethane nylon shrinkable resin is, by definition, compressible, which is likely to favor bedsores.

It is therefore clear that, in the prior art, there is a lack of materials capable of constituting solid / solid interfaces, intended for comfort and / or protection and which meet all the expected specifications. In this state of affairs, one of the essential objectives of the present invention is to propose a material capable of being used, in particular, for the manufacture of articles improving the comfort and / or the protection of individuals at the solid interface. / solid with their contact environment, said material having to be suitable for the prophylactic treatment of bedsores. Another objective of the invention is to provide a material for such solid / solid interfaces, which is capable of providing optimal comfort and which is light, so as to allow the provision of articles of the easy cushion or mattress type. To manipulate.

Another essential objective of the present invention is to provide a material of comfort and / or protection at the solid / solid interfaces, which is endowed with self-massaging properties, as well as mechanical and viscoelastic properties allowing it to perfectly fit the curve of the body (deformability), without however being compressible (suppression of wrinkles).

Another essential objective of the present invention is to provide a comfort and / or protection material for a solid / solid interface, which is a light elastomer, easy to obtain, effective for comfort and protection and / or damping against shock and economic.

Another essential objective of the present invention is to provide a process for the continuous production of the material aimed at in the objectives stated above. Another essential objective of the invention is to provide a process for continuously obtaining such a material which is easy to use and inexpensive in terms of operating cost and raw material cost.

Another essential objective of the present invention is to provide comfort and / or protective articles, such as anti-decubitus cushions and mattresses, protective elements (in particular ears, elbows or heels), dressings or many more lining and protection sheets for equipment, made from the solid / solid interface material mentioned in the objectives stated above.

SUMMARY OF THE INVENTION:

Part of these objectives, among others, are achieved by the present invention which relates, first of all, to a material:

- likely to be used, in particular, for the manufacture of articles improving the comfort and / or protection of individuals at the solid-solid interface with their contact environment,

- And of the type of those comprising an elastomer gel, characterized in that it comprises:

- a non-thermoplastic, deformable and incompressible elastomer gel, - and a filler included in the gel and constituted by particles of density less than or equal to that of the gel. The material according to the invention is, at the same time, light, comfortable and effective in the prophylactic treatment of bedsores.

The judicious selection of a non-thermoplastic, deformable and incompressible elastomer gel, on the one hand, and the inclusion of a particular load of low density in this gel, on the other hand, corresponds to an inventive approach having led to characteristics original and advantageous which make it possible to avoid wrinkling of the skin at the solid / solid interface between the individual and the comfort and / or protection article produced from said material according to the invention. This has the consequence of minimizing the shear forces acting on the tissues and causing the ischemias which cause bedsores.

In addition, the material according to the invention has particularly appreciable self-massing properties. The fact that this material has two properties, a priori contradictory, namely, on the one hand, incompressibility (absence of change in volume under the effect of pressure) and, on the other hand, the deformability, allow it to perfectly fit the curve of the body of the user of the solid / solid interface based on said material. This light and incompressible elastomer produces such effects for the following reasons: the depression of the mass of gel by the part of the body coming to bear on it causes regular emergence, at the immediate periphery of the depressed surface, d '' a mass of a total volume equivalent to that pressed in, mass defining a contact surface with the additional body capable of contributing to the distribution of the driving force over a larger contact surface and therefore of significantly lowering the specific pressure at the body / gel interface. By incompressible is meant, within the meaning of the present invention, the ability of the material to have a substantially zero reduction in volume under the effect of a pressure of several bars.

DETAILED DESCRIPTION OF THE INVENTION:

It should be noted that the density of the elastomer gel, serving as a matrix for the particulate load, is advantageously between 1 and 1.25 g / cm ³ , preferably of the order of 1.10 g / cm ³ .

According to a preferred arrangement of the invention, this elastomeric gel comprises polyurethane.

This polyurethane elastomer gel has a shear stiffness capable of ensuring a "self-stabilizing" character to the articles in the constitution of which it would enter. In addition, this incompressible lightened polyurethane elastomer gel has very high punching resistance allowing it to withstand very high specific local pressures.

As a characteristic of this polyurethane gel, it is also possible to point out a total absence of thermoplastic behavior at use temperatures (for example + 10 ° C to + 60 ° C).

In addition, the polyurethane gels selected in accordance with the invention have high chemical and physical stability. In particular, no change in the dimensional and mechanical characteristics of this type of gel is observed. Finally, it is not uninteresting to note that the polyurethane gel according to the invention has a non-flammable character.

Advantageously, this polyurethane elastomer is of the type obtainable by different synthesis techniques, in which one reacts: ^D at least one isocyanate, preferably a diisocyanate, chosen, more preferably still, from the following list:

- tolylene diisocyanate (TDI),

- modified TDI,

- diphenylmethanediisocyanate (MDI), - aliphatic diisocyanates,

- And mixtures thereof, ^π with at least one compound with mobile hydrogen, preferably chosen from alcohols and, more preferably still, from glycols. These preferred alcoholic comonomers, that are the glycols or diols, are selected, in practice, from the following list:

^D alkylene diol, preferably ethanediol, propanediol, butanediol, ° polyether glycol, preferably polyethylene glycol (PEG), polytetramethylene ether glycol (PTMEG), polypropylene glycol (PPG), ^π polyesterglycol, preferably polyadipate, polycaprolactone, ^π and their mixtures. As examples of mobile hydrogen compounds which can be used to prepare the polyurethane gel of the material according to the invention, mention may be made of butanediol, as well as PTMEG and PPG.

MDIs are good examples of suitable isocyanates.

Alternatively, the polyurethane can be obtained by reaction of an isocyanate and a polyol of high molecular weight, such as a macrodiol

(polyether glycol and / or polyesterglycol). In this variant, it is possible to use, in addition to the polyol, a chain extender selected from: ^π alcohols, preferably diols and / or triols and, more preferably still, alkylene diols (eg butanediol) and their mixtures, ^G primary or secondary amines (alone or as a mixture between them), preferably 4, 4'-methylene-bis (2-chloroaniline), ^π polyols and / or polyamines, ^D and their mixtures. According to the invention, the particulate charge is of particular technical importance. It contributes to the lightening of the material of the solid / solid interface and contributes to giving it its essential property of incompressibility, without sacrificing its deformability.

In view of the reduction sought, it is advantageous for the density of the particles, expressed in g / cm ³ , to be less than or equal to 0.30, preferably to 0.20 and, more preferably still, is between 0 , 10 and 0, 14. These ranges of density of the particles correspond to values of average nominal real densities. The bulk density of these particles is approximately 5 / 100th less than the average actual nominal density, so the preferred range for this bulk density is 0.05 to 0.10 g / cm ³ .

Advantageously, the constituent material of the particles is chosen from the following list: glass, ceramics and their mixtures, glass being particularly preferred.

In practice, glass, which constitutes the preferred constituent material, is chosen from chemically stable glasses (amorphous silica - borosilicate of lime and sulfur -). To further improve the performance of the material according to the invention, it is preferable that the particles have substantially the form of microspheres, preferably hollow, with a particle size less than or equal to 400 μm, preferably between 100 and 250 μm and, more preferably again, between 150 and 200 μm. These microspheres (microballoons or microbeads) are, advantageously hollow and comprise a rigid shell conferring particular properties on the matrix in incompressible elastomer gel in which they are embedded.

As examples of particles, mention may be made of 3M Kl glass microspheres, sold by the company OMYA and having a nominal density of 0.125 g / cm ³ . The quantity of particulate fillers introduced into the elastomer matrix is an important parameter of the invention. Preferably, this particulate charge represents between 5 and 50% by volume, preferably between 25 and 50% by volume and, more preferably still, of the order of 40% by volume.

In any event, the proportions of elastomer gel and of particulate fillers are chosen such that the solid / solid interface material has a density, expressed in g / cm ³ , of less than 1, preferably less than 0 , 8 and, more preferably still, of the order of 0.7.

It should be emphasized that the material according to the invention is thermostable between approximately 5 "C and approximately 80 'C. Furthermore, its rheological or viscoelastic characteristics are such that it has:

- cone penetration (NF T 77.104) between 10 and 30 mm at 25 ° C,

- and a residual deformation (NF T 56.112) of - 5 mm at 25 "C.

According to another of its characteristics, the anti-decubitus padding material according to the invention can be shaped by molding, optionally thermomolding or rotational molding.

The preparation of said material can be carried out by simple mixing of the particulate filler with the incompressible elastomer gel, in a discontinuous or continuous mode. For this, recourse is had to known and appropriate means in themselves, namely any type of mixer with blades or turbines or the like ...

To ensure a homogeneous mixture of the particulate fillers within the elastomer matrix, provision is made, in accordance with the invention, for implementing a system of permanent agitation of the components to be homogenized. In the case where the elastomer gel consists of polyurethane, the applicant has had the merit of highlighting that it is entirely advantageous gradually incorporating the particulate filler into the polyol / isocyanate mixture, during and / or after the preparation of said mixture. Preferably, this particulate filler is introduced shortly after bringing the polyol (s) into contact with the isocyanate (s). This introduction can, for example, take place between a few seconds and a few minutes after the aforementioned contact (eg about 10 seconds). This incorporation is accompanied by stirring of the medium. By proceeding in this way, the reduction in viscosity of the medium due to the exothermic start of the reaction of the polyol with the isocyanate is fully exploited.

There are continuous mixing devices which are perfectly adaptable to the continuous embodiment of the process for preparing the material according to the invention. The examples below will illustrate this.

INDUSTRIAL APPLICATIONS:

As regards its applications, the padding and / or protection material according to the invention obviously finds an immediate outlet in the manufacture of articles improving the comfort and / or the protection of individuals with a solid interface / solid with their contact environment. It follows that, according to another of its aspects, the subject of the invention is such articles comprising the aforesaid material, which is contained in a pocket, preferably polymer, said pocket possibly being contained in at least one cover or any other flexible or rigid envelope.

The articles considered can be soles or slippers - in particular soles or slippers for shoes for specific uses (ski boots, ice skates, roller skates), cushions, mattresses, mattress toppers, protections for elbows, ears, heels or for any other part of the body, dressings, sheets for filling and / or protection of apparatus, cushions or the like for all types of seats (eg sports stadium seats or performance halls, vehicle seats), saddles for horses or replacement tires for wheeled vehicles.

By way of examples, mention may be made of the cushions intended for prophylactic treatment of pressure sores and consisting mainly of:

- a bag made of elastomeric material particularly resistant to tearing and aging (for example in extruded thermoplastic polyurethane elastomer), - an incompressible, deformable and thermostable elastomer gel, which is molded inside the bag and which is formulated and added to a particulate charge of hollow glass microspheres, so as to have a density much less than 1 (concentration of particulate charges = about 40% by volume);

- a possible waterproof cover coating the gel bag and intended to facilitate cleaning of the assembly;

- And a possible comfort cover, for example in fleece or not, preferably sterilizable.

Such cushions are particularly suitable as anti-bed sore articles. In the same way, it is possible to manufacture over-mattresses or anti-decubitus mattresses, in particular decubitus.

The invention will be better understood in the light of the following nonlimiting examples of the preparation of the anti-decubitus material according to the invention, in a discontinuous mode and in a continuous mode. These examples will also highlight the alternative embodiments and the advantages of the invention. The description of the example of the continuous preparation method will be made with reference to the single appended figure, which represents a simplified diagram of a device suitable for the implementation of said method.

EXAMPLES

EXAMPLE 1 PREPARATION OF A COMPOSITE ANTI-PRESSURE MATERIAL ACCORDING TO THE INVENTION: INCOMPRESSIBLE DEFORMABLE POLYURETHANE GEL / HOLLOW GLASS MICROSPHERES -

DISCONTINUOUS MODE.

A quantity of 748 g of isocyanates necessary for molding a part is prepared, such as a cushion of 400 x 400 x 23 mm. This isocyanate is an MDI of the 4,4'-diphenylmethane-isocyanate type sold by the company MAFFA

INTERNATIONAL, under the brand "POLYGEL", reference 30 B.

This isocyanate is subjected to strong stirring and then stored in a suitable container.

The quantity of polyol necessary for molding the above cushion is prepared, at a rate of 312.5% of the quantity of isocyanates. The polyol used is a butane diol, of the type sold under the brand "POLYGEL 30 A" by the

MAFFA INTERNATIONAL Company. This corresponds to an amount of 2,337 g.

A volume of 3M Kl type glass microspheres of nominal density = 0.125 g / cm ³ is prepared, sold by the company OMYA DISTRIBUTION, under the brand name "SCOTCHLITE ^® " from 3M. The volume required is 40% of the total volume of isocyanate + polyol.

The polyol is introduced into the isocyanate and stirred vigorously for 10 seconds.

The microspheres are then incorporated into the surface of the mixture and the container is shaken to disperse these microspheres. The total amount of microspheres is then introduced gradually. After approximately two minutes of homogenization in the mixing container equipped with stirring means with blades rotating at 100 revolutions / minute.

An incompressible and lightened composite elastomeric material is thus collected, capable of being used as padding in anti-decubitus articles, of the type of those mentioned above. EXAMPLE 2 - PREPARATION OF A COMPOSITE MATERIAL ANΠ-PRESSURES ACCORDING TO THE INVENTION: INCOMPRESSIBLE DEFORMABLE POLYURETHANE GEL / HOLLOW GLASS MICROSPHERES - CONTINUOUS MODE.

The continuously operating device, used in this example, is shown in the accompanying single figure. It comprises, on the one hand, means for mixing and bringing the polyol and the isocyanate into contact and, on the other hand, means for incorporating and homogenizing the particulate charge in the polyol / reactive mixture. isocyanate.

These means 1 comprise a tank 3 of isocyanate and a tank 4 of polyol connected one and the other to a mixing member 5, via pipes 6 equipped with solenoid valves 7. The member 5 is a turbine provided with a motor M capable of rotating a mixing shaft 8. In addition to this mixing action, the shaft 8 routes the isocyanate / polyol medium to the head 9 of the organ outlet 5. This head 9 is connected to means 2 by means of a supply hose for means 2 in isocyanate / polyol reactive mixtures. The means 2 comprise a hopper 11 containing the glass microspheres and the lower outlet conduit of which is in relation to a feed metering screw 12, actuable by a motor M. This hopper 11 is also equipped with a vibrator 13 with pneumatic supply allowing to fight against the caking of the particulate charge. The dosing screw 12 of the means 2 is capable of bringing the desired quantity of particulate charges into a turbine 13 equipped with a mixing shaft 14, itself driven by a motor M. This shaft 14 allows the homogenization of the particulate charge with the isocyanate / polyol reactive mixture. The resulting composite material is expelled from the turbine 13 by the outlet head 15, to then be collected and used as a raw material for padding and / or protection. The methodology implemented is as follows.

The isocyanate, the polyol and the microspheres are identical to those of Example 1. The isocyanate is degassed after having loaded it into tank 3 and the same is done for the polyol contained in tank 4.

The hopper 11 is filled with the microspheres, so as to be able to supply the homogenization means 2 (metering and distribution system). The microspheres loaded in the hopper are, if necessary, demolded using the vibrator 13.

The dosing screw 12 is adjusted, as are the shafts 14 and 8 of the turbines 13 and 5 respectively, so that the dosage of the polyol relative to the polyol / isocyanate mixture is 32% by weight and so that the titer volume by particulate charge of the composite material is of the order of 40% volume. The feed flow rate of the turbine 5 is adjusted by the isocyanate 3 and polyol 4 tanks using the metering pump not shown in the drawing. After switching on the device, the composite material according to the invention is produced continuously.

Claims

CLAIMS:

1 - Material:

an elastomeric gel preferably comprising polyurethane and having the property of being non-thermoplastic, deformable and incompressible,

- And a filler included in the gel and made up of particles with a density less than or equal to that of the gel.

2 - Material according to claim 1, characterized in that the elastomeric gel comprises polyurethane, of the type of those obtainable by different synthesis techniques, in which one reacts: ^π at least one isocyanate, preferably a diisocyanate, chosen, more preferably again, from the following list:

- tolylene diisocyanate (TDI),

- modified TDI, - diphenylmethanediisocyanate (MDI),

- aliphatic diisocyanates,

- and their mixtures,

° with at least one mobile hydrogen compound, preferably chosen from alcohols and, more preferably still, from glycols.

3 - Material according to claim 1 or 2, characterized in that the density of the particles, expressed in g / cm ³ , is less than or equal to 0.30, preferably 0.20 and, more preferably still, is included between 0.10 and 0.14.

4 - Material according to any one of claims 1 to 3, characterized in that the constituent material of the particles is chosen from the following list: glass, ceramics and their mixtures, glass being particularly preferred. 5 - Material according to any one of claims 1 to 4, characterized in that the particles have substantially the form of microspheres, preferably hollow, with a particle size less than or equal to 400 μm, preferably between 100 and 250 μm and, more preferably still, between 150 and 200 μm. 6 - Material according to any one of claims 1 to 5, characterized in that its particle load represents between 5 and 50% by volume, preferably between 25 and 50% by volume and, more preferably still, of the order 40% by volume.

7 - Material according to any one of claims 1 to 6, characterized in that it has a density, expressed in g / cm ³ , less than 1, preferably less than 0.8 and, more preferably still, of around 0.7.

8 - Material according to any one of claims 1 to 7, characterized in that it is thermostable between about 5 "C and about 80" C.

9 - A method of manufacturing the material according to any one of claims 1 to 8, characterized in that the elastomer gel is a polyurethane gel and in that the particulate filler is gradually incorporated into the polyol / isocyanate mixture, during and / or after the completion of said mixture.

10 - Article improving the comfort and / or protection of individuals at the solid / solid interface with their contact environment, characterized in that it comprises material according to any one of claims 1 to 8, contained in a pocket , preferably made of polymer, said pocket possibly being contained in at least one cover.