BARRIER COMPOSITION COMPRISING A TALC PARTICULATE

Abstract

A talc particulate having a d.sub.50 ranging from about 7 m to about 13 m and a BET surface area equal to or less than about 23 m.sup.2/g, barrier compositions and polymeric compositions comprising said talc particulate, use of said talc particulate to decrease permeability of a composition, use of said talc particulate in an inner lining of a tire, methods of making said barrier compositions, polymeric compositions and tire inner linings.

Claims

1. A barrier composition comprising a talc particulate having a d.sub.50 ranging from about 7 m to about 13 m and a BET surface area equal to or less than about 23 m.sup.2/g.

2. The barrier composition of claim 1, wherein the talc particulate has a d.sub.50 ranging from about 8 m to about 12 m.

3. The barrier composition of claim 1, wherein the talc particulate has a BET surface area ranging from about 8 to about 22 m.sup.2/g.

4. The barrier composition of claim 1, wherein the talc particulate has a lamellarity index less than about 5.

5. The barrier composition of claim 1, wherein the talc particulate has a d.sub.95 ranging from about 20 m to about 36 m.

6. The barrier composition of claim 1, wherein the talc particulate has a d.sub.75 ranging from about 10 m to about 22 m.

7. The barrier composition of claim 1, wherein the talc particulate has a d.sub.25 ranging from about 4 m to about 9 m.

8. The barrier composition of claim 1, wherein the talc particulate is or comprises a wet milled talc.

9. A polymer composition comprising an elastomer and a talc particulate according to claim 1.

10. The polymer composition of claim 9, wherein the amount of talc particulate in the polymer composition ranges from about 10 to about 80 phr.

11. The polymer composition of claim 9, further comprising carbon black.

12. The polymer composition of claim 10, further comprising, carbon black, wherein the amount of carbon black in the polymer composition ranges from about 10 to about 100 phr.

13. The polymer composition of claim 11, wherein the total amount of talc and carbon black in the polymer composition ranges from about 10 to about 40 vol %.

14. The polymer composition of claim 9, wherein the polymer composition has an oxygen transmission rate equal to or less than about 180 cm.sup.3/m.sup.2/day.

15. The polymer composition of claim 9, wherein the polymer composition has a tensile strength of at least about 6 MPa.

16. The polymer composition of claim 9, wherein the polymer composition has an elongation at break of at least about 700%.

17. The polymer composition of claim 9, wherein the polymer composition has an elastic modulus (100%) of at least about 0.6 MPa.

18. The polymer composition of claim 9, wherein the polymer composition has an elastic modulus (300%) of at least about 1.8 MPa.

19. The polymer composition of claim 9, wherein the polymer composition has a Shore A hardness of at least about 35.

20. A tire having an inner lining comprising the polymer composition of claim 9.

21-24. (canceled)

Description

DETAILED DESCRIPTION

[0025] A barrier composition comprising an inorganic particulate is disclosed herein. It has surprisingly and advantageously been found that the inorganic particulate disclosed herein can be used in polymer compositions to provide barrier properties that are at least as good or are improved compared to polymer compositions that do not comprise an inorganic particulate or that comprise a different inorganic particulate that is currently used in the same type of polymer compositions. Though talc is referred to in the examples herein, it should be understood that the invention should not be limited to talc and can include other inorganic particulate (e.g. mica). The talc disclosed herein may therefore be used to at least partially replace any other inorganic particulates (e.g. carbon black) present in a polymer composition. This may, for example, enable a smaller mass or volume or particulates to be used in the polymer compositions. In addition, it has surprisingly and advantageously been found that incorporation of the talc disclosed herein into polymer compositions does not substantially alter their mechanical properties.

Talc Particulate

[0026] The term talc refers to either magnesium silicate mineral, or the mineral chlorite (magnesium aluminium silicate), or a mixture of the two, optionally associated with other minerals, for example, dolomite and/or magnesite. The term talc may also refer to a synthetic talc, also known as talcose.

[0027] The talc particulate may, for example, be obtained from a lamellar talc ore. The talc particulate may not, for example, be obtained from a microcrystalline ore. The talc particulate may, for example, be a wet milled talc.

[0028] The talc particulate may, for example, be a blend of two or more talcs. For example, one of the two or more talcs may be in accordance with the talc particulate disclosed herein. For example, one of the two or more talcs may be a micronized talc, for example a micronized talc having a d.sub.50 ranging from about 1 m to about 3 m, for example from about 1.5 m to about 2.5 m, for example from about 2 m to about 2.4 m.

[0029] The talc particulate disclosed herein has a d.sub.50 ranging from about 7 m to about 13 m. For example, the talc particulate disclosed herein may have a d.sub.50 ranging from about 7.5 m to about 12.5 m or from about 8 m to about 12 m or from about 8.5 m to about 11.5 m or from about 9 m to about 11 m or from about 9.5 m to about 10.5 m.

[0030] The talc particulate disclosed herein may, for example, have a d.sub.95 ranging from about 20 m to about 36 m. For example, the talc particulate disclosed herein may have a d.sub.95 ranging from about 21 m to about 35 m or from about 22 m to about 34 m or from about 23 m to about 33 m or from about 24 m to about 32 m or from about 25 m to about 31 m or from about 26 m to about 30 m or from about 27 m to about 29 m or from about 28 m to about 29 m.

[0031] The talc particulate disclosed herein may, for example, have a d.sub.75 ranging from about 10 m to about 22 m. For example, the talc particulate disclosed herein may have a d.sub.75 ranging from about 11 m to about 21 m or from about 12 m to about 20 m or from about 13 m to about 19 m or from about 14 m to about 18 m or from about 15 m to about 17 m or from about 16 m to about 17 m.

[0032] The talc particulate disclosed herein may, for example, have a d.sub.25 ranging from about 4 m to about 9 m. For example, the talc particulate disclosed herein may have a d.sub.25 ranging from about 4.5 m to about 8.5 m or from about 5 m to about 8 m or from about 5.5 m to about 7.5 m or from about 6 m to about 7 m.

[0033] Unless otherwise stated, particle size measurements are obtained by wet Malvern laser scattering (standard AFNOR NFX11-666 or ISO 13329-1). In this method, the size of particles in powders, suspensions and emulsions may be measured using the diffraction of a laser beam, based on an application of Mie theory. Such a machine, for example a Malvern Mastersizer S (as supplied by Malvern Instruments) provides measurements and a plot of the cumulative percentage by volume of the particles which have a size, referred to in the art as equivalent spherical diameter (esd) less than given esd values. The mean particle size d.sub.50 is the value determined in this way of the particle esd at which there are 50% by volume of the particles which have an esd less than that d.sub.50 value.

[0034] The talc may, for example, have a lamellarity index equal to or less than about 5. For example, the talc may have a lamellarity index equal to or less than about 4.9 or equal to or less than about 4.8 or equal to or less than about 4.7 or equal to or less than about 4.6 or equal to or less than about 4.5 or equal to or less than about 4.4 or equal to or less than about 4.3 or equal to or less than about 4.2 or equal to or less than about 4.1 or equal to or less than about 4 or equal to or less than about 3.9 or equal to or less than about 3.8 or equal to or less than about 3.7 or equal to or less than about 3.6 or equal to or less than about 3.5 or equal to or less than about 3.4 or equal to or less than about 3.3 or equal to or less than about 3.2 or equal to or less than about 3.1 or equal to or less than about 3. The talc may, for example, have a lamellarity index equal to or greater than about 1.5 or equal to or greater than about 1.6 or equal to or greater than about 1.7 or equal to or greater than about 1.8 or equal to or greater than about 1.9 or equal to or greater than about 2 or equal to or greater than about 2.1 or equal to or greater than about 2.2 or equal to or greater than about 2.3 or equal to or greater than about 2.4 or equal to or greater than about 2.5. For example, the talc may have a lamellarity index ranging from about 2 to about 5 or from about 2.2 to about 5 or from about 2.5 to about 5 or from about 2.8 to about 5.

[0035] The lamellarity index is defined as (d.sub.meand.sub.50)/d.sub.50 in which d.sub.mean is the value of the mean particle size (d.sub.50) obtained by a particle size measurement by wet Malvern laser scattering (standard AFNOR NFX11-666 or ISO 13329-1) as described above and d.sub.50, for the purposes of the lamellarity index calculation, is the value of the median diameter obtained by sedimentation using a sedigraph (standard AFNOR X11-683 or ISO 13317-3). The sedigraph method uses a Sedigraph 5100 machine supplied by Micromeritics Instruments Corporation, Norcross, Ga., USA (www.micromeritics.com), referred to as Micromeritics Sedigraph 5100 Unit. Such as machine provides measurements and a plot of the cumulative percentage by weight of particles having a size, referred to in the art as the equivalent spherical diameter (esd), less than given esd values. The mean particle size d.sub.50 is the value determined in this way of the particle esd at which there are 50% by weight of the particles which have an esd less than that d.sub.50 value. Reference may be made to the article by G. Baudet and J. P. Rona, Ind. Min. Miners et Carr. Les techn. June, July 1990, pp 55-61, incorporated herein by reference, which shows that this index is correlated to the mean ratio of the largest dimension of the particle to its smallest dimension.

[0036] The talc particulate may, for example, have a BET surface area equal to or less than about 23 m.sup.2/g. For example, the talc particulate may have a BET surface area equal to or less than about 22 m.sup.2/g equal to or less than about 21 m.sup.2/g or equal to or less than about 20 m.sup.2/g or equal to or less than about 19 m.sup.2/g or equal to or less than about 18 m.sup.2/g or equal to or less than about 17 m.sup.2/g or equal to or less than about 16 m.sup.2/g or equal to or less than about 15 m.sup.2/g or equal to or less than about 14 m.sup.2/g or equal to or less than about 13 m.sup.2/g or equal to or less than about 12 m.sup.2/g. The talc particulate may, for example, have a BET surface area equal to or greater than about 5 m.sup.2/g or equal to or greater than about 6 m.sup.2/g or equal to or greater than about 7 m.sup.2/g or equal to or greater than about 8 m.sup.2/g or equal to or greater than about 9 m.sup.2/g or equal to or greater than about 10 m.sup.2/g or equal to or greater than about 11 m.sup.2/g. The talc particulate may, for example, have a BET surface area ranging from about 5 to about 23 m.sup.2/g or from about 8 to about 23 m.sup.2/g or from about 10 to about 23 m.sup.2/g. The talc particulate may, for example, have a BET surface area ranging from about 5 to about 20 m.sup.2/g or from about 8 to about 20 m.sup.2/g or from about 10 to about 20 m.sup.2/g.

[0037] The BET surface area is defined as the area of the surface of the particles of the talc particulate with respect to unit mass, determined according to the BET method by the quantity of nitrogen adsorbed on the surface of said particles so as to form a monomolecular layer completely covering said surface (measurement according to the BET method, AFNOR standard X11-621 and 622 or ISO 9277, or any method equivalent thereto).

Barrier Compositions

[0038] There is also disclosed herein a barrier composition comprising the talc particulate disclosed herein, including all aspects and embodiments thereof, including all combinations thereof. Barrier compositions are any compositions that serve to reduce or prevent the passage of gases and/or liquids. The barrier composition may, for example, be a polymer composition comprising, consisting essentially of or consisting of an elastomer and a talc particulate according to any aspect or embodiment disclosed herein.

[0039] The elastomer may, for example, be selected from butyl rubber (copolymer of isobutylene and isoprene), chlorinated butyl rubber, brominated butyl rubber, polyisoprene (e.g. synthetic polyisoprene or natural polyisoprene), natural rubber, styrene butadiene, nitrile rubber (a copolymer of butadiene and acrylonitrile), hydrogenated nitrile rubber, a copolymer of isobutylene and paramethylstyrene, a brominated copolymer of isobutylene and paramethylstyrene, ethylene propylene rubber, ethylene propylene diene rubber, epichlorohydrin rubber, polyacrylic rubber, silicone rubber, fluorosilicone rubber, polyether block amides, chlorosulfonated polyethylene, ethylene-vinyl acetate, or any copolymer or blend thereof. The present invention may tend to be discussed in terms of butyl rubber, for example BrIIR 2030. However, the present invention should not be construed as being limited as such.

[0040] The polymer composition may be cured/vulcanized. Alternatively, the polymer composition may not be cured/vulcanized. Vulcanization may be conducted in the presence of a sulphur vulcanizing agent, such as, elemental sulphur or sulphur-donating vulcanizing agents, for example, an amine disulphide, polymeric disulphide or sulphur olefin adducts. Sulphur vulcanizing agents may be used in an amount ranging from about 0.2 to about 5 phr, for example from about 0.5 to about 3 phr.

[0041] The polymer composition may, for example, comprise from about 10 phr to about 80 phr of the talc particulate disclosed herein. For example, the polymer composition may comprise from about 15 to about 75 phr or from about 20 to about 70 phr or from about 25 to about 65 phr or from about 30 to about 60 phr or from about 35 to about 55 phr or from about 40 to about 50 phr of the talc particulate. The term phr relates to parts by weight of a particular ingredient per 100 parts by weight of polymer.

[0042] The polymer composition may comprise one or more additional ingredients. For example, the polymer composition may further comprise carbon black (a form of paracrystalline carbon produced by incomplete combustion of heavy petroleum products). For example, the polymer composition may consist essentially of or consist of an elastomer, a talc particulate as disclosed herein and carbon black.

[0043] The polymer composition may, for example, comprise from about 10 to about 100 phr of carbon black. For example, the polymer composition may comprise from about 20 to about 90 phr or from about 30 to about 80 phr or from about 40 to about 70 phr or from about 50 to about 60 phr of carbon black.

[0044] The polymer composition may, for example, comprise from about 10 vol % to about 40 vol % total talc particulate and carbon black. For example, the total amount of talc particulate and carbon black present in the polymer composition may range from about 15 vol % to about 35 vol % or from about 20 vol % to about 30 vol %.

[0045] Other conventional ingredients may also be present in the polymer compositions. For example, one or more curing aids, tackifier resins, plasticizers, processing aids, other minerals (e.g. silica (e.g. precipitated silica), clay, mica or combinations thereof), accelerators (e.g. primary or secondary accelerators, e.g. amines, disulphides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamate, xanthates), coupling agents (e.g. bis(3-trialkyoxysilylpropyl polysulphides), antioxidants, antiozonants, stearic acid, activators, lubricants, anti-degradants, waxes and oils may be present in the polymer compositions. Each additional ingredient may, for example, be present in the polymer composition in an amount ranging from about 0.2 to about 5 phr, for example from about 0.5 to about 3 phr.

[0046] The polymer composition may, for example, have an oxygen transmission rate equal to or less than about 180 cm.sup.3/m.sup.2/day. For example, the polymer composition may have an oxygen transmission rate equal to or less than about 170 cm.sup.3/m.sup.2/day or equal to or less than about 160 cm.sup.3/m.sup.2/day or equal to or less than about 150 cm.sup.3/m.sup.2/day or equal to or less than about 140 cm.sup.3/m.sup.2/day or equal to or less than about 130 cm.sup.3/m.sup.2/day or equal to or less than about 120 cm.sup.3/m.sup.2/day or equal to or less than about 110 cm.sup.3/m.sup.2/day. For example, the polymer composition may have an oxygen transmission rate equal to or greater than about 10 cm.sup.3/m.sup.2/day, for example equal to or greater than about 20 cm.sup.3/m.sup.2/day or equal to or greater than about 40 cm.sup.3/m.sup.2/day or equal to or greater than about 50 cm.sup.3/m.sup.2/day or equal to or greater than about 60 cm.sup.3/m.sup.2/day or equal to or greater than about 70 cm.sup.3/m.sup.2/day or equal to or greater than about 80 cm.sup.3/m.sup.2/day.

[0047] The oxygen transmission rate may be measured after curing/vulcanization of any polymer (e.g. elastomer) present in the composition, according to ASTM D3985 or ASTM F1927 or ASTM F2622.

[0048] The oxygen transmission rate of the polymer composition may be no more than about 20% less than the oxygen transmission rate of a corresponding polymer composition that does not comprise the talc particulate disclosed herein (i.e. a composition that is identical to said polymer composition except that it does not comprise the talc particulate). The corresponding polymer composition may comprise a different talc that is not in accordance with the talc particulate disclosed herein. Alternatively the corresponding polymer composition may not comprise any talc particulate. For example, the oxygen transmission rate of the polymer composition may be no more than about 15% less or no more than about 10% less or no more than about 5% less than the oxygen transmission rate of a corresponding polymer composition that does not comprise the talc particulate. For example, the oxygen transmission rate of the polymer composition may be approximately the same, for example the same, as the oxygen transmission rate of a corresponding polymer composition that does not comprise the talc particulate. The oxygen transmission rate of the polymer composition may be up to about 60% greater or up to about 55% greater or up to about 50% greater or up to about 45% greater or up to about 40% greater or up to about 35% or up to about 30% greater than the oxygen transmission rate of a corresponding polymer composition that does not comprise the talc particulate disclosed herein.

[0049] The polymer composition may, for example, have a tensile strength of at least about 6

[0050] MPa. For example, the polymer composition may have a tensile strength equal to or greater than about 6.1 MPa or equal to or greater than about 6.2 MPa or equal to or greater than about 6.3 MPa or equal to or greater than about 6.4 MPa or equal to or greater than about 6.5 MPa or equal to or greater than about 6.6 MPa or equal to or greater than about 6.7 MPa or equal to or greater than about 6.8 MPa or equal to or greater than about 6.9 MPa or equal to or greater than about 7 MPa. For example, the polymer composition may have a tensile strength equal to or less than about 9 MPa or equal to or less than about 8.5 MPa or equal to or less than about 8 MPa.

[0051] Tensile strength may be measured after curing/vulcanization of any polymer (e.g. elastomer) present in the composition, according to ASTM D412.

[0052] The polymer composition may, for example, have an elongation at break of at least about 700%. For example, the polymer composition may have an elongation at break of at least about 710% or at least about 720% or at least about 730% or at least about 740% or at least about 750% or at least about 760% or at least about 770% or at least about 780% or at least about 790% or at least about 800% or at least about 810% or at least about 820% or at least about 830% or at least about 840% or at least about 850%. For example, the polymer composition may have an elongation at break of up to about 1000% or up to about 950% or up to about 900%.

[0053] Elongation at break may be measured after curing/vulcanization of any polymer (e.g. elastomer) present in the composition, according to ASTM D412.

[0054] The polymer composition may, for example, have an elastic modulus (100%) of at least about 0.6 MPa. For example, the polymer composition may have an elastic modulus (100%) of at least about 0.7 MPa or at least about 0.8 MPa or at least about 0.9 MPa or at least about 1 MPa or at least about 1.1 MPa or at least about 1.2 MPa. For example, the polymer composition may have an elastic modulus (100%) of up to about 1.5 MPa or up to about 1.4 MPa or up to about 1.3 MPa.

[0055] The polymer composition may, for example, have an elastic modulus (300%) of at least about 1.8 MPa. For example, the polymer composition may have an elastic modulus (300%) of at least about 1.9 MPa or at least about 2 MPa or at least about 2.1 MPa or at least about 2.2 MPa or at least about 2.3 MPa. For example, the polymer composition may have an elastic modulus (300%) of up to about 3 MPa or up to about 2.8 MPa or up to about 2.6 MPa or up to about 2.5 MPa.

[0056] The elastic modulus (100% or 300%) may, for example, be measured after curing/vulcanization of any polymer (e.g. elastomer) present in the composition, according to ASTM D1456.

[0057] The polymer composition may, for example, have a Shore A hardness of at least about 35. For example, the polymer composition may have a Shore A hardness of at least about 36 or at least about 37 or at least about 38 or at least about 39 or at least about 40. The polymer composition may, for example, have a Shore A hardness up to about 45 or up to about 44 or up to about 43 or up to about 42 or up to about 41.

[0058] The Shore A hardness may be measured after curing/vulcanization of any polymer (e.g. elastomer) present in the composition, according to ASTM D2240.

[0059] The polymer composition may, for example, have a tear resistance of at least about 20 kN/mm. For example, the polymer composition may have a tear resistance of at least about 21 kN/mm or at least about 22 kN/mm or at least about 23 kN/mm or at least about 24 kN/mm or at least about 25 kN/mm. For example, the polymer composition may have a tear resistance up to about 40 kN/mm or up to about 39 kN/mm or up to about 38 kN/mm or up to about 37 kN/mm or up to about 36 kN/mm or up to about 35 kN/mm or up to about 30 kN/mm.

[0060] The tear resistance may be measured after curing/vulcanization of any polymer (e.g. elastomer) present in the composition, according to ASTM D624.

[0061] The mechanical properties of the polymer composition may differ by no more than about 30% (+or 30%) in comparison to the mechanical properties of a corresponding polymer composition that does not comprise the talc particulate disclosed herein (i.e. a composition that is identical to said polymer composition except that it does not comprise the talc particulate). The corresponding polymer composition may comprise a different talc that is not in accordance with the talc particulate disclosed herein. Alternatively the corresponding polymer composition may not comprise any talc particulate. Mechanical properties refers to one or more of tensile strength, elongation at break, elastic modulus (e.g. 100% or 300% elastic modulus), Shore A hardness and tear resistance.

[0062] The mechanical properties of the polymer composition may, for example, differ by no more than about 29% or no more than about 28% or no more than about 27% or no more than about 26% or no more than about 25% or no more than about 24% or no more than about 23% or no more than about 22% or no more than about 21% or no more than about 20% or no more than about 19% or no more than about 18% or no more than about 17% or no more than about 16% or no more than about 15% or no more than about 14% or no more than about 13% or no more than about 12% or no more than about 11% or no more than about 10%. For example, the mechanical properties of the polymer composition may differ by 0% to about 30% or from about 1% to about 20% or from about 5% to about 10%.

[0063] In other embodiments, the talc particulates disclosed herein may be used in barrier compositions and/or membranes.

Products

[0064] The polymer compositions disclosed herein may, for example, be used to make various products. For example, the polymer compositions disclosed herein may be used to make the inner lining of tires. Thus, also disclosed herein is a tire inner lining comprising a polymer composition according to any aspect or embodiment disclosed herein. Also disclosed herein is a tire comprising an inner lining according to any aspect or embodiment disclosed herein.

[0065] The tire may, for example, be any vehicle tire, for example a passenger tire or truck tire. The tire may, for example, be a pneumatic tire. The tire may, for example, comprise one or more of a tire carcass, belt, tread, undertread, shoulder, side wall, bead heel and rim.

[0066] The inner lining of the tire may, for example, have a thickness ranging from about 0.01 cm to about 1 cm, for example from about 0.05 cm to about 1 cm, for example from about 0.05 cm to about 0.5 cm. This may depend on the size and intended use of the tire.

Uses

[0067] The talc particulates disclosed herein (including all aspects and embodiments thereof, including all embodiments thereof) may be used to provide barrier properties in a barrier composition. A barrier composition is any composition that is used to reduce or prevent the passage of one or more gases and/or liquids through said composition.

[0068] The talc particulates disclosed herein may, for example, be used to decrease the permeability of a polymer composition. For example, the talc particulates disclosed herein may be used to decrease the oxygen transmission rate of a polymer composition. For example, incorporation of the talc particulate disclosed herein into a polymer composition may, for example, decrease the oxygen transmission rate of a polymer composition by at least about 10% or at least about 15% or at least about 20% or at least about 25% or at least about 30% or at least about 35% or at least about 40% or at least about 45% or at least about 50%.

[0069] The mechanical properties of the polymer composition into which the talc particulate is incorporated may not change by more than about 30% (+or 30%). For example, the mechanical properties of the polymer composition into which the talc particulate is incorporated may not change by more than about 25% or more than about 20% or more than about 15% or more than about 10%. Mechanical properties includes, for example, tensile strength, elongation at break, elastic modulus (100% and/or 300%), Shore A hardness and tear resistance.

[0070] The talc particulates disclosed herein may, for example, be used to at least partially replace carbon black or any other inorganic particulate in a polymer composition. For example, the talc particulates disclosed herein may be used to replace at least about 20 wt % or at least about 30 wt % or at least about 40 wt % or at least about 50 wt % of carbon black and/or any other inorganic particulate in a polymer composition. For example, the talc particulate disclosed herein may be used to replace up to about 100 wt % or up to about 90 wt % or up to about 80 wt % of the carbon black and/or any other inorganic particulate in a polymer composition.

[0071] The talc particulates disclosed herein may, for example, be used in a tire inner lining. For example, the talc particulates disclosed herein may be used to decrease the permeability (e.g. decrease the oxygen transmission rate) of a tire inner lining. The oxygen transmission rate and mechanical properties of a tire inner lining may change as described above in relation to polymer compositions.

Methods

[0072] There is also disclosed herein methods for making the talc particulates, barrier compositions, polymer compositions, tire inner linings and tires disclosed herein, including all aspects and embodiments thereof.

[0073] The talc particulates may, for example, be made by grinding and/or milling the talc ore to obtain a desired particle size distribution. For example, the talc particulate may be obtained by wet milling. The talc may, for example, be prepared by any of the methods disclosed EP 0971988 or EP 2146793, which are incorporated herein by reference.

[0074] The barrier compositions and/or polymer compositions, may, for example, be prepared by blending the talc particulate with one or more of the other ingredients present in the barrier composition or polymer composition. For example, the polymer composition may be made by blending the talc particulate with an elastomer.

[0075] Mixing of the polymer composition can be accomplished by methods known to those skilled in the art. For example, the ingredients may be mixed in multiple stages, for example one non-productive stage followed by a productive stage. The final curatives (e.g. sulphur vulcanizing agents) may be mixed in the final stage which is conventionally called the productive mix stage in which the mixing typically occurs at a temperature or ultimate temperature lower than the mix temperatures of the preceding and non-productive mix stages. The terms non-productive and productive mix stages are well known to those skilled in the art.

[0076] A tire inner lining composition may be formed into a gum strip (e.g. produced by a press or passing an elastomer compound through a mill, calender, extruder or other suitable means). Preferably, the gum strip is produced by a calender to obtain good uniformity. The uncured/unvulcanised gum strip may then be constructed as an inner surface (exposed inside surface) of an uncured rubber tire structure (e.g. the carcass). The inner lining of the tire is then co-cured/co-vulcanized (e.g. sulphur co-cured/co-vulcanized) with the tire carcass during the tire curing operation under conditions of heat and pressure. As a result, the inner lining may become an integral part of the tire.

[0077] Vulcanization is generally carried out, for example, at temperatures ranging from about 100 to about 200 C., preferably from about 110 to about 180 C. Any of the usual vulcanization processes may be used, such as heating in a press or mold, heating with superheated steam or hot salt or in a salt bath.

EXAMPLES

Example 1

[0078] A talc filler having a BET surface area of 15.3 m.sup.2/g and a d.sub.50 of 9.5 m (laser measurement as described above) was used to make a composition suitable for use as a tire inner lining.