WO1999010169A1

WO1999010169A1 - Elastic laminate material useful in contact with a human body

Info

Publication number: WO1999010169A1
Application number: PCT/SE1998/001438
Authority: WO
Inventors: Peter Porsgaard
Original assignee: Rehband Anatomiska Ab
Priority date: 1997-08-25
Filing date: 1998-08-05
Publication date: 1999-03-04
Also published as: SE9703064L; SE9703064D0; SE510065C2; AU8565398A

Abstract

An elastic laminate material (multi-layer material, sandwich material) intended to be used for various purposes in which the material may be used in direct contact with human skin, and which comprises a base material (1) of an elastic, porous foam material, preferably a material having closed cells, and a stretchable or elastic surface layer (2) on one side or on both sides thereof, preferably a knitted material like a 'stretch material', a tricot/woven material, a piquet material etc., which has been fixed to the base material (1) by means of an intermediate glue layer (3), and in which the base material (1) comprises an elastomeric material which does not contain any chlorine compounds, for instance EPDM rubber, SBR rubber or NBR rubber, and in which the glue layer (3) comprises a thermoplastic melt glue of the type which is dry and non-sticking in cold condition but which has good adhesive properties in heated condition, for instance an EVA glue, a glue of polyolefine, a poylester, a polyethylene or a polyurethane.

Description

ELASTIC LAMINATE MATERIAL USEFUL IN CONTACT WITH A HUMAN BODY

The present invention relates to an elastic laminate material (multi-layer material, sandwich material) intended to be used in various connections in which the material may be used in direct contact with human skin. Such materials are known which are used as bandaging materials, for instance as support bandages, as a protection means and a support for the back, the neck, for joints like knees, elbows, wrists etc. but also as dresses or overalls, for instance as wet dresses for diving purposes, etc.

Elastic laminate materials or combination materials for the said purposes are known, which materials generally comprise

- a base material in the form of a foam material, preferably a material having closed cells, for instance a pore containing rubber material like foam rubber of a chloroprenic material or a corresponding rubber material manufactured in that a blowing agent is mixed into a chloroprenic material, the material is allowed to expand and vulcanize to the desired size and shape,

- a surface layer on one side, or on both sides of the base material and comprising a stretchable or elastic surface material, preferably a knitted material or an elastic fabric/tricot material or a corresponding material, for instance a polyamide fabric (Nylon®), for instance stretch Nylon, Nylon jersey, Nylon piquet or another stretchable or elastic fabric having a high elasticity, which does not obstruct the action of the foam material or the rubber material,

- and in which the woven surface material has been fixed to the foam rubber material by means of contact adhesive, generally in a solution of an aromatic hydrocarbon like toluene, which may contain residuals of benzene, xylene and other hydrocarbons.

By "elastic" materials in meant, in this connection, a material having rubber elastic properties, which upon removal of load regains its original shape, but also thermoplastic elastomers, which can stand an elongation of up to 200%, or more, but which may regain their original shapes more slowly than rubber materials.

It should be mentioned that it is, in the first place, the elastic base material which, in functional respect, creates the elasticity of the laminate material. The fabric and the glue material have to be stretchable so as to follow the motions of the base material without providing any substantial resistance. The fabric and the glue material, however, may in itself also be more or less elastic. The said known material has good technical properties as concerns interconnection of the laminate, as concerns elasticity, bendability, heat insulation, weather resistance, capacity of standing several washings, ability of standing freezing etc., and the described laminate material comprising chloroprenic foam rubber, stretch Nylon and contact adhesive has for several years been used for the above mentioned purposes. It has shown, however,

- both that the foam rubber material can cause skin eruptions or allergic reactions, especially for persons having a delicate skin, probably for the reason that the chloroprenic material can give off irritating chlorine compounds;

- and also that the solvent of the contact adhesive, which can be toluene, xylene or a similar aromatic hydrocarbon, can migrate and can give off odours and rests of toluene and other hydrocarbons, and also rests of heavy metals, what can also cause negative skin reactions and can lead to irritating odours.

Depending on the properties of the said material it has not been possible to have said material certified up to the desired class according to OKOTEX standard 100, product class 2. It can be expected that there will, in short, also be EU regulations in this area.

The object of the invention therefore has been to solve the problem of providing an elastic laminate material comprising a base of an elastic foam material having closed cells, a stretchable or elastic, preferably knitted surface layer material, and a likewise stretchable or elastic binder between the foam material base and the surface layer material, and which laminate material has no such components which can give off substances that may lead to skin eruptions, allergic reactions or annoying odours, and which can be used in direct contact with human skin, even by persons having very delicate skin. The primary object of the invention has been to find an elastic base material of foam rubber type, which is free from chlorine compounds and other compounds which can lead to skin problems and other non-desired effects, and to find a material which can be used for strong and safe inter- gluing of the laminate material.

A useful foam material for the laminate base is an elastomeric material of the type ethene-diene-terpolymer, so called EPDM rubber, which elastomer can be obtained as a synthetic foam rubber material having closed cells, and which has proved to give substantially the same good technical effect as the previously used chloroprenic foam rubber material, but which does not have the undesired effects of said chloroprenic foam rubber. The EPDM foam material can be sulphur vulcanized or peroxide vulcanized and thermo cured. Other possible foam materials for the base material are styrene- butadiene rubber (SBR rubber) or acrylonitrile-butadiene rubber (NBR rubber). It is also possible to use a type of urethane material. The SBR rubber, however, does not give as good quality as the EPDM foam rubber; the NBR rubber may, at long time use, give certain negative medical effects; and urethane rubber is not so hydrolysis resistant as EPDM rubber and can be subjected to changes at long time contact with water.

A problem with EPDM rubber is that it is difficult to have adhesive stick to said material, and it is therefore difficult to have the surface layer of a textile material stick to the EPDM foam rubber. Extensive tests have, however, surprisingly proved that it is possible to provide a both strong and elastic joint between EPDM foam rubber and the textile layer using a thermoplastic melt glue, for instance in the form of a glue film or a melt glue material in powder form, which glue has no adhesivity (does not stick) in cold state, but which gets a good adhesivity when heated, especially in combination with a pressure treatment.

The glue must not contain any substances which are inappropriate from medical viewpoints or any ingredients which are harmful to the environment, and the glue must be so stretchable or elastic that it can be stretched more than the foam rubber material, for instance more than 200%. The glue also has to be water resistant and should have good weather resistant properties, it has to be resistant against UV radiation and it should have such characteristics that no damages appear in the glue even upon strong bendings and turnings of the laminate material comprising a foam rubber material and a fabric. A well suitable glue is an ether-vinyl-acetate glue, generally called EVA glue, which gives an elastic and very good joint when foam rubber, a film or a powder of glue and the textile layer are heated and compressed concurrently therewith. The glue joining can be made at a temperature of 1 20-1 80°C and at a pressure of 4-8 bar for a period of 1 0-20 seconds. Glue joining also can be made by means of so called hot-melt technics using some type of heat transmitting apparatus, like en IR heating apparatus or any other known technics.

Other useful types of glue are polyolefines or polyesthers. It is also possible to make use of a polyethylene film or a polyurethane film.

The film of glue can be an EVA film or a polyolefine film or a type of polyesther film, which is perforated. Alternatively it is possible to use a thin film of another material on which dots of EVA, of a polyolefine or a polyesther has been applied, and which dots are activated to provide a glue joint using heat and pressure.

It is very difficult to provide a glue joint on a conventional hydrocarbon material of the type EPDM foam rubber. It is therefore surprising that it has been possible to provide a very good high-strength, water resistant and stretchable or elastic glue joint having good weather resistant and good cold resistant properties between the EPDM foam rubber and the textile material using a thermoplastic glue film or a thermoplastic powder of the said type. The laminate material of the actual type should be of a type that can be used as a clothing material which can be sewed, glued and eventually welded together.

In the accompanying drawings figure 1 is an exploded view of a laminate material according to the invention. Figure 2 diagrammatically shows the method of joining the parts of the laminate material. Figures 3, 4 and 5 are diagrams showing various properties of a laminate material according to the invention.

The laminate material shown in figures 1 and 2 comprises a base material 1 of a synthetic foam rubber material having closed cells, for instance an EPDM foam rubber, which is laminated with a surface layer 2 of a textile material, for instance a stitched textile material, like stretch Nylon®. In the illustrated case it is shown that the glue joint 3 comprises a glue foil of a thermoplastic meltable glue, for instance an ethene-vinyl-acetate glue, generally called EVA film. It is shown that the glue foil is perforated, and this improves the elastic properties of the glue film. Alternatively to using a glue film it is possible to spray the foam rubber base 1 and/or the surface layer 2 with a dry powder of the same type of material, or to apply drops of melted glue on the base material 1 and/or on the surface layer 2.

As diagrammatically indicated in figure 2 the gluing together of a base material 1 , which can have a thickness of 1 .5 to 10 mm, a surface layer 2, which can have a thickness of up to 0.3 to 1 .5 mm, and the intermediate glue film 3 is made in that a pressure 4 is applied, for instance a pressure of 4-8 bar, at the same time as the glue film is heated to a temperature of 1 20-1 80°C. The heat can be obtained by IR radiation or by any other known technics. The pressure and the heat are maintained for a period of 10-20 seconds.

As an alternative material to said foam rubber material of the type

EPDM rubber it is possible to use another elastomeric material of foam type having closed cells, for instance SBR rubber (styrene-butadiene rubber) or

NBR rubber (acrylonitrile-butadiene rubber). As an alternative to the stretchable or elastic glue film of EVA type it is possible to use a corresponding glue film of a polyolefine, a polyesther, a polyethylene or possibly a polyurethane.

For judging the different properties of a laminate material comprising a foam rubber material which is free from chlorine substances and a textile surface layer, and having a glue joint of a thermoplastic melt glue, several tests have been made with various laminate combinations. The results thereof are shown in figures 3, 4 and 5.

In figure 3 there is shown the tensile strength up to rupture of the new laminate material after the material has been washed 1 -8 times at a temperature of 40°C. In figure 4 there is shown the elongation up to rupture of the laminate material, likewise are 1 -8 washings. In figure 5 there is shown the peeling (de-scaling) effect of the surface layer from the base material at various peeling (de-scaling) forces and likewise after 1 -8 washings of the laminate material. As a reference material in all tests there was used a laminate material of the above mentioned known type comprising chloroprenic foam rubber, stretch Nylon® and a contact glue of a well known type.

ANALYSIS OF LAMINATE MATERIAL HAVING THERMOPLASTIC GLUE FILMS

Several glue films have been tested with respect to providing a glue joint between EPDM foam rubber and a stretch Nylon® material. The glue films were supplied by Borealis under the designation OE0467, EVA OE501 9, EEA OE581 0 and EBA OE6420. In all tests the thickness of the glue films was 80μm. The EDPM foam rubber had a thickness of 3.5 mm, and the surface layer was stretch Nylon® having a thickness of about 1 mm. The EPDM foam rubber had the following composition: Polymer EPDM 32%

Softener: mineralic oil 29%

Carbon black 15% Filler material: calcium carbonate having some addition of Al, Si and traces of Zn, Ti 24%

It has proved possible to vary the thickness of the foam material between 1 .5 and 10 mm, and that the fabric material can be given a thickness of for instance 0.3 - 1 .5 mm.

The following tests were made: tensile strength, made account for in figure 3, elongation unto rupture, made account for in figure 4 and peeling force, made account for in figure 5.

For judging the tensile strength unto rupture and the elongation of the laminate material judgings were made after the laminate material had been washed 2, 4 and 8 times, respectively. The washings were made at 40°C and the laminate material was dried in air. The tests were made of laminate materials having a thickness of 3.5 mm. The diagrams in figures 3 and 4 show that the tensile strength unto rupture and the elongation of the material remained practically unchanged after said 8 washings. The results of the tensile strength tests according to figure 3 also show that the tensile strength unto rupture was practically the same for the laminate according to the invention as for the previously known chloroprenic/contact glue material, which was used as a reference material. Figure 4 shows that the elongation unto rupture was slightly less than for the reference material, but such little difference was deemed neglectible.

There were also made peeling (descaling) tests as a function of the number of washings. The tests were made so that a traction force was applied between the foam rubber material and the textile surface layer. The results are shown in figure 5. It is evident that the peeling force was almost unchanged after all washings. It is also evident that the peeling force was, in fact, greater for the actual material of the present invention than for the previsously known "chloroprenic material".

The resistance to bendings was tested in further tests after simulated ageing caused by UV radiation. It proved that the new laminate materials showed only an insignificantly increased stiffness after the 8 washings and the UV radiation treatment. Also no increase of stiffness could be noted after the laminate material pieces had been subjected to freezing.

It could be established that the adhesion provided by the thermoplastic films was sufficient for all of the above mentioned films, and that the adhesion did not show to decrease noticeably after 8 washings. The UV treatment lead to an insignificant reduction of the tensile strength and of the elongation unto rupture. No reduction of the delamination force could be observed after 100 hours of UV radiation. Also freezing of the laminate materials did not seem to influence the properties of the materials according to the test as concerns the resistance to bendings.

It also could be established that the new laminate material, in all respects, showed the same good technical properties as the previously known "chloroprenic material" . No chlorine compounds or other harmful compounds can be given off from the new material. Also the thermoplastic glue layer does not give off any substances or odours.

Claims

C L A I M S

1 . An elastic laminate material (multi-layer material, sandwich material) intended to be used for various purposes in which the material may be used in direct contact with human skin and comprising a base material (1 ) of an elastic, porous foam material, preferably a material having closed cells, and a stretchable surface layer (2) on one side or on both sides thereof, preferably a knitted material like a "stretch material", a tricot woven material, a piquet material or a similar material, which has been fixed to the base material (1 ) by means of an intermediate layer (2) of glue, characterized in that the base material (1 ) is an elastomeric material which does not contain any chorine compounds, and in that the glue layer (2) comprises a thermoplastic melt glue of the type which is dry and non-sticking i cold condition but which has good adhesive properties in heated condition.

2. A laminate material according to claim 1 , characterized in that the base material comprises a foam rubber material of a polymer of the type ethene-propene-butadiene-terpolymer material (EPDM).

3. A laminate material according to claim 1 , characterized in that the base material comprises a foam rubber material of a thermoplastic elastomer like styrene-butadiene rubber (SBR) or acrylonitrile-butadiene rubber (NBR).

4. A laminate material according to claim 1 , 2 or 3, characterized in that the glue joint is made by means of a thermoplastic melt glue (2) in the form of a glue foil, a dry glue powder or dots of glue which have been applied on the foam rubber base (1 ) and/or on the surface layer (2) of textile material.

5. A laminate material according to claim 4, characterized in that the glue foil (3) is perforated.

6. A laminate material according to claim 4 or 5, characterized in that the glue layer is made of an ethene-vinyl-acetate glue (EVA).

7. A laminate material according to claim 4 or 5, characterized in that the glue layer is made of a polyolefine, a polyesther, a polyethylene or a polyurethane material.

8. A laminate material according to any of the preceding claims, characterized in that the glue layer has an optimum melt point of 1 20-1 80°C.

9. A laminate material according to any of the preceding claims, characterized in that the laminate material comprises a foam rubber base (1 ) having a thickness of for instance between 1 .5 and 1 0 mm, a textile surface layer on one or both sides of the foam rubber base (1 ) having a thickness of about 1 mm, and in which the parts of the laminate material have been glued together by a pressure of 4-8 bar and a temperature of 1 20-1 80°C for a glue joining time of 1 0-20 seconds.

10. A laminate material according to any of the preceding claims, characterized in that the laminate material has such characteristic and structure that it can be used as a clothing material which can be sewed, glued or eventually welded.

AMENDED CLAIMS

[received by the International Bureau on 19 January 1999 (19.01.99); original claims 1-10 replaced by amended claims 1-8

(2 pages)]

1 . An elastic laminate material (multi-layer material, sandwich material) intended to be used for various purposes whereby the material may be used in direct contact with human skin and comprising a base material (1 ) of an elastic, porous foam material, preferably a material having closed cells, and a stretchable surface layer (2) on one side or on both sides thereof, preferably a knitted material like a "stretch material", a tricot woven material, a piquet material or a similar material, which has been fixed to the base material (1 ) by means of an intermediate layer (3) of glue, characterized in that the base material (1 ) is an elastomeric material which does not contain any chlorine compounds, like a foam rubber material of a polymer of the type ethene- propene-butadiene-terpolymer material (EPDM) or a foam rubber material of a thermoplastic elastomer like styrene-butadiene rubber (SBR) or acrylonitrile- butadiene rubber (NBR), and in that the glue layer (3) comprises a thermoplastic melt glue of the type which is dry and non-sticking i cold state but which has good adhesive properties in heated state.

2. A laminate material according to claim 1 , characterized in that the glue joint is made by means of a thermoplastic melt glue (3) in the form of a glue foil, a dry glue powder or dots of glue which have been applied on the foam rubber base (1 ) and/or on the surface layer (2) of textile material.

3. A laminate material according to claim 2, characterized in that the glue foil (3) is perforated.

4. A laminate material according to claim 2 or 3, characterized in that the glue layer is made of an ethene-vinyl-acetate glue (EVA).

5. A laminate material according to claim 2 or 3, characterized in that the glue layer is made of a polyolefine, a polyesther, a polyethylene or a polyurethane material.

6. A laminate material according to any of the preceding claims, characterized in that the glue layer has an optimum melt point of 120-180°C.

7. A laminate material according to any of the preceding claims, characterized in that the laminate material comprises a foam rubber base (1 ) having a thickness of for instance between 1.5 and 10 mm, a textile surface layer on one side or on both sides of the foam rubber base (1 ) and having a thickness of about 1 mm, and in which the parts of the laminate material have been glued together using a pressure of 4-8 bar and a temperature of 1 20-1 80°C and a glue joining time of 1 0-20 seconds.

8. A laminate material according to any of the preceding claims, characterized in that the laminate material has such characteristics and such structure that it can be used as a clothing material which can be sewed, glued or eventually welded.