SELF-REPAIRING MULTILAYER ELASTOMER COMPOSITIONS

Abstract

Provided are multilayer elastomer compositions such as multilayer films which possess the ability to self-repair upon puncturing. The multilayer elastomer compositions may be prepared from, for example, styrenic block copolymers and find use in the manufacture of thin walled articles, for example gloves, particularly medical or industrial gloves.

Claims

1. A multilayer elastomer composition comprising two outer barrier layers (L1 and L3) and one or more inner layers (L2) disposed between the outer barrier layers, wherein at least one inner layer comprises fluid-filled droplets, wherein said fluid-filled droplets comprise a water swellable liquid composition.

2. A multilayer elastomer composition according to claim 1, comprising one or more further layers.

3. A multilayer elastomer composition according to claim 1, wherein the fluid-filled droplets comprise a liquid diluent which is substantially immiscible with the elastomer of the inner layer.

4. A multilayer elastomer composition according to claim 3, wherein the liquid diluent comprises less than 12% by weight water.

5. A multilayer elastomer composition according to claim 1, wherein the water swellable liquid composition comprises superabsorbent polymer.

6. A multilayer elastomer composition according to claim 1, wherein the each of layers L1, L2 and L3, independently comprise elastomer selected from the group consisting of natural rubber, polybutadiene, polyisoprene, polychloroprene, polyurethane, acrylic polymers or copolymers, silicone elastomers, SBR (Styrene Butadiene Rubber) copolymers, SBCs (Styrenic Block Copolymers such as, for example, SBS, SIS, SEBS or SEEPS), Nitrile Butadiene Rubber copolymers, x-NBR (carboxylated Nitrile Butadiene Rubber) copolymers, butyl rubber, fluoroelastomer, styrene butadiene styrene and blends thereof.

7. A multilayer elastomer composition according to claim 6, wherein the SBC independently comprises one or a mixture of SBCs of number average molecular weight (Mn) above 100,000 g/mol.

8. A multilayer elastomer composition according to claim 1, wherein the layers independently comprise one or more plasticizers.

9. A multilayer elastomer composition according to claim 8, wherein the plasticizer comprises a liquid, or a mixture of liquid, saturated polyolefins compatible with the midblock (elastomeric block) of an SBC.

10. A multilayer elastomer composition according to claim 8, wherein the plasticizer is selected from one or more vegetable oils, such as sunflower, rapeseed, or coconut oil or an oligomer or other elastomer that possesses sufficient compatibility with the rubbery mid-blocks, such as a low molecular weight polybutadiene, polyisoprene, polyisobutene, amorphous polyolefin copolymers of propylene and ethylene, and butyl rubber.

11. (canceled)

12. A multilayer elastomer composition according to claim 1, wherein the outer layer L1 comprises two superimposed layers, L1a (external) and L1b (in contact with L2).

13. A multilayer elastomer composition according to claim 12, wherein L1b comprises a formulated SBC composition and L1a comprises a chemically crosslinked synthetic rubber, such as polychloroprene, polyisoprene or nitrile butadiene rubber.

14. A multilayer elastomer composition according to claim 3, wherein the liquid diluent has a viscosity between about 50 and about 5000 mPa.Math.s.

15. A multilayer elastomer composition according to claim 3, wherein the liquid diluent is one or more polyols.

16. (canceled)

17. A multilayer elastomer composition according to claim 5, wherein the superabsorbent polymer is an anionic superbsorbent polymer selected from the group consisting of polyacrylic acid, poly(lactic acid), saponified vinyl acetate-acrylic ester copolymer, hydrolysed acrylonitrile powder, hydrolysed acrylamide copolymer, ethylene-maleic anhydride copolymer, sulfonated polystyrene, poly(aspartic acid), poly(vinylphosphonic acid), poly(vinylsulfonic acid), poly(vinylphosphoric acid, poly(vinylsulfuric acid) and mixtures thereof.

18. A multilayer elastomer composition according to claim 5, wherein the superabsorbent polymer is a cationic superabsorbent polymers selected from the group consisting of polyvinylamine, poly(dialkylaminoalkyl(meth)acrylamide), a polyethylenimine, a polymer prepared from the ester analog of an N-(dialkylamino(meth)acrylamide), a poly 2-dimethylaminoethylmethacrylate, a poly 2-dimethylaminoethylacrylate, a polydiallyldimethylammonium chloride, a poly(vinylguanidine), a poly(allylguanidine), a poly(allylamine), a poly(dimethyldialkylammonium hydroxide), a quaternized poly(meth)acrylamide or ester analog thereof, poly(vinylalcohol-co-vinylamine) and mixtures thereof.

19. A multilayer elastomer composition according to claim 5, wherein the superabsorbent polymer has a particle size in the range 0.1 to 20 micron, preferably 0.1 to 5 micron.

20. A multilayer elastomer composition according to claim 1, wherein the water swellable liquid composition further comprises an anionic surfactant.

21. A multilayer elastomer composition according to claim 1, wherein the water swellable liquid composition further comprises one or more crosslinkers.

22. (canceled)

23. A multilayer elastomer composition according to claim 1, wherein the volume fraction of the fluid-filled droplets expressed in the dry film for layer L2 is from 1 to 65%.

24. A multilayered elastomer composition according to claim 1, wherein the total thickness of the multilayer composition is between about 10 microns and about 1500 microns, preferably between about 50 microns and about 1000 microns, more preferably between about 100 microns and about 500 microns.

25. (canceled)

26. An article of manufacture comprising a multilayer elastomer composition according to claim 1 wherein the article is a glove.

27. (canceled)

28. (canceled)

29. (canceled)

30. (canceled)

31. (canceled)

32. (canceled)

33. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0099] FIG. 1 is a schematic of a multilayer composition according to one embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0100] The following is a detailed description of the disclosure provided to aid those skilled in the art in practicing the present disclosure. Those of ordinary skill in the art may make modifications and variations in the embodiments described herein without departing from the spirit or scope of the present disclosure.

[0101] Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure, the preferred methods and materials are now described.

[0102] It must also be noted that, as used in the specification and the appended claims, the singular forms ‘a’, ‘an’ and ‘the’ include plural referents unless otherwise specified. Thus, for example, reference to a ‘SBC’ may include more than one SBCs, and the like.

[0103] Throughout this specification, use of the terms ‘comprises’ or ‘comprising’ or grammatical variations thereon shall be taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof not specifically mentioned.

[0104] Unless specifically stated or obvious from context, as used herein, the term ‘about’ is understood as within a range of normal tolerance in the art, for example within two standard deviations of the mean. ‘About’ can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear from context, all numerical values provided herein in the specification and the claim can be modified by the term ‘about’.

[0105] Any methods or processes provided herein can be combined with one or more of any of the other methods or processes provided herein.

[0106] Ranges provided herein are understood to be shorthand for all of the values within the range. For example, a range of 1 to 50 is understood to include any number, combination of numbers, or sub-range from the group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50.

[0107] Reference will now be made in detail to exemplary embodiments of the disclosure. While the disclosure will be described in conjunction with the exemplary embodiments, it will be understood that it is not intended to limit the disclosure to those embodiments. To the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the disclosure as defined by the appended claims.

EXAMPLE

[0108] The following example demonstrates the improved performance (self-repairing when in contact with water) of a multilayer composition according to the present disclosure.

[0109] In this example, the glove is made of three layers, L1, L2 and L3.

[0110] Layers 1 and 3

[0111] The elastomer composition of Layers 1 and 3 is made of Styrenic Block Copolymer (SBC) and more specifically SEBS with a radial structure containing 31% of polystyrene and a viscosity of 75cp in toluene at 5% concentration.

[0112] The elastomer is blended with a resin made of styrene and substituted styrene (Mn=800 g/mol, polydispersity index=2.8), and a white mineral oil with a viscosity of 68 mPas at 40° C. as a plasticizer.

[0113] These components are dissolved in a mixture of methylcyclohexane and toluene (8:2) to form a solution having 18% solid content by weight.

[0114] The amount of resin is 20 phr, and the amount of plasticizer is 60 phr.

[0115] The solution designated as “L1/3-MIX” is stored at ambient temperature in an appropriate vessel covered to prevent solvent evaporation.

[0116] Layer 2

[0117] The elastomeric ingredients used for Layer 2 are similar than those used for the Layers 1 and 3 described above. For Layer 2, the amount of resin is 10 phr and the amount of plasticizer is 45 phr.

[0118] These components are dissolved in a mixture of methylcyclohexane and toluene (8:2) to form a solution having 18% solid content by weight. This solution is designated “continuous phase”.

[0119] The water swellable composition is composed of polyethylene glycol (molecular weight of 400 g/mol) mixed with a cationic polymer particle (superabsorbent polymer) made of poly 2 dimethylaminoethylmethacrylate.

[0120] The quantity of superabsorbent polymer is 10% compared to the polyethylene glycol 400.

[0121] The dispersion of superabsorbent polymer is performed under high shear to allow a proper particle dispersion in the presence of benzalkonium chloride that serves as a dispersant (5% of the total composition). This liquid phase is designated “dispersed phase”.

[0122] Under shear, the “dispersed phase” is gently added into the “continuous phase” in order to obtain a final emulsion, designated “L2-MIX” which is stored under light shearing to prevent destabilization and sedimentation. The volume fraction Fv of the droplets, expressed in the dry film (that is, after evaporation of the solvent) is 40%.

[0123] Multilayer films were obtained following solvent evaporation after dipping a porcelain glove mould into the “L1/3-Mix” first, using a dipping robot with controlled dipping speeds.

[0124] The film is allowed to dry at 40° C. for 15 minutes before performing another dipping in the same mixture, following by another drying of 15 minutes at 40° C. The Layer 1 is the result of these two thin layers.

[0125] Layer 2 is then applied on top of Layer 1 by dipping in the “L2-MIX”. A continuous film incorporating the water composition inside the droplets is formed upon evaporation of the solvent.

[0126] The film is then allowed to dry at 40° C. for 30 minutes before depositing Layer 3.

[0127] Layer 3 is deposited by dipping in the “L1/3-MIX”, then the film is allowed to dry first at 40° C. during 15 minutes before a final drying at 75° C. for 1 hour. After stripping, the film is placed in an oven at 60° C. for 6 hours to remove trace amounts of residual solvent.

[0128] The film is packed in a pouch consisting of a thin layer of aluminium, a metal that has very high oxygen and moisture barrier properties (therefore rendering extremely difficult for water to pass through the film) then exposed to electron beam radiation at a dose of 25±2 kGy.

[0129] A small glove breach is simulated in a glove finger using a 0.3 mm acupuncture needle, then the finger is gently filled with colored water. Application of minor pressure on the finger facilitates the water passing across the film through the hole. Almost immediately after contact with water, the hole is filled with the gel formed by the superabsorbent polymer, stopping the passage of water.

[0130] The contents of all references, and published patents and patent applications cited throughout the application are hereby incorporated by reference. Those skilled in the art will recognize that the disclosure may be practiced with variations on the disclosed structures, materials, compositions and methods, and such variations are regarded as within the ambit of the disclosure.

[0131] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments and methods described herein. Such equivalents are intended to be encompassed by the scope of the following claims.

[0132] It is understood that the detailed examples and embodiments described herein are given by way of example for illustrative purposes only, and are in no way considered to be limiting to the disclosure. Various modifications or changes in light thereof will be suggested to persons skilled in the art and are included within the spirit and purview of this application and are considered within the scope of the appended claims. For example, the relative quantities of the ingredients may be varied to optimize the desired effects, additional ingredients may be added, and/or similar ingredients may be substituted for one or more of the ingredients described.

[0133] Additional advantageous features and functionalities associated with the systems, methods, and processes of the present disclosure will be apparent from the appended claims. Moreover, those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the disclosure described herein. Such equivalents are intended to be encompassed by the following claims.