NOVELTY - Composite material (I) comprises rubber, a sulfur-containing vulcanizing agent, a layered double hydroxide (LDH) comprising hydroxyl and/or an organic anion as charge-balancing anion(s), and less than 1.5 per hundred rubber (phr) of zinc oxide.    USE - (I) is useful in: tyres (claimed) including car tyres, truck tyres, tractor tyres, off-the-road tyres and aircraft tyres. (I) is useful in winter tyres, in latex products (including gloves, condoms, balloons, catheters, latex thread, foam, carpet backings and rubberized coir and hair), in footwear, civil engineering products such as bridge bearings, rubber-metal-laminated bearings, in belting and hoses, in non-tyre automotive applications including engine mounts, rubber bearings, seals, grommets, washers, boots, wires and cables, pipe seals, medical closures, rollers, small solid tyres, mountings for domestic and commercial appliances, rubber balls and tubing, milking inflations and other agricultural-based applications, in coating compositions, pressure sensitive adhesive compositions, plastic hardcoats, and paper release coating compositions, and in fiber finishing applications including textile and hair care applications, sealants, adhesives, encapsulants, and solar cell units. The rubber composition is useful in undertread or tread base, the tread, the sidewall, the rim cushion, the inner layer, the carcass, the apex, the bead, and the belt layer.    ADVANTAGE - (I) is free of eco-toxic zinc. The cured composite material (I) has improved dynamical and mechanical properties, good heat stability, dimensional stability, tear strength, scratch resistance, flame resistance, and/or strength-to-weight ratios. The cured (I) has low permeability towards gases and/or liquids, such as nitrogen, carbon dioxide, oxygen, water vapor and hydrocarbons. The cured (I) exhibits improved elongation at break and strength at break compared to neat rubber material that does not comprise LDH. (I) exhibits good dynamic properties (e.g. a low tan delta) during deformation at constant force, thus showing good viscoelastic properties, allowing the production of tyres with a low heat build-up and rolling resistance. (I) has a reduced amount of conventional activators, such as zinc oxide. The LDH causes the rubber to have an improved puncture resistance. (I) enhance the bonding or adhesion between different rubbers, e.g. in different parts of the tyre, or between rubber and metal, or between rubber and fibers. (I) is transparent to visible light, hence improves light yield and solar energy recovery. Due to improved mechanical properties, the adhesive power and the tear strength of (I) is increased and the solar cell unit is capable of withstanding the weather effects or other mechanical forces to which it is exposed, and the lifetime of the solar cell unit is increased. The LDH is easily mixed in the rubber, enabling a uniform distribution of LDH particles throughout the rubber within an even shorter time, rendering the manufacturing process more economical. The LDH, when added as an extender oil or solid, no solvent has to be removed, leading to a further reduction in processing time and to an improved process safety.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a cured composite material obtainable by curing (I);    (2) a masterbatch comprising a rubber or cured rubber (30-90 wt.%), a layered double hydroxide (9-69 wt.%) comprising hydroxyl and/or an organic anion as charge-balancing anion(s), and a sulfur-containing vulcanizing agent (1-20 wt.%);    (3) a rubber-free mixture of a sulfur-containing vulcanizing agent and a layered double hydroxide comprising hydroxyl and/or an organic ion as charge-balancing anion(s); and    (4) a process for preparing (I) comprising (a1) contacting the layered double hydroxide, optionally mixed with a first solvent, with a rubber comprising one or more polymers and optionally a second solvent; or (a2) contacting the layered double hydroxide, optionally mixed with a first solvent, with a composition comprising one or more monomers of a rubber and optionally a second solvent, and polymerizing the monomers to form the rubber; (b) contacting the sulfur-containing vulcanizing agent with the rubber or the monomers prior to, during or after step (a1) or step (a2); and (c) optionally removing the first and/or second solvent during or after any one of steps (a1), (a2), or (b).