Shoe sole

The shoe sole according to any one of the preceding claims, wherein the rubber matrix material comprises from 20 to 99.5 wt. %, preferably from 30 to 99.5 wt. %, more preferably from 30 to 80 wt. %, more preferably from 40 to 80 wt. %, more preferably from 50 to 80 wt. %, more preferably from 50 to 70 wt. % of the total weight of the shoe sole.

The shoe sole according any one of the preceding claims, wherein the rubber matrix material is at least 30 wt. %, preferably at least 35 wt. %, more preferably at least 40 wt. %, more preferably at least 45 wt. %, more preferably at least 50 wt. %, more preferably at least 55 wt. %, more preferably at least 60 wt. %, more preferably at least 65 wt. %, more preferably at least 70 wt. % butadiene rubber based on the total weight of the rubber matrix material.

The shoe sole according to any one of the preceding claims, wherein the butadiene rubber comprises or consists of styrene butadiene rubber.

The shoe sole according to any one of the preceding claims, wherein the rubber matrix material has a density of from 50 to 120 kg m−3, more preferably from 60 to 110 kg m−3, more preferably from 70 to 100 kg m−3, more preferably from 85 to 100 kg m−3.

The shoe sole according to any one of the preceding claims, wherein the shoe sole comprises less than 5 wt. %, or less than 2 wt. %, or less than 1 wt. %, or less than 0.5 wt. % of natural rubber, or wherein the shoe sole is substantially free of natural rubber.

The shoe sole according to any one of the preceding claims comprising 0.5 to 15 wt. % of the carbon nanoparticles based on the total weight of the shoe sole.

The shoe sole according to any one of the preceding claims, wherein the functionalised carbon nanoparticles are carbon nanoparticles that are one or more of:

• oxygen-functionalised, hydroxy-functionalised, carboxy-functionalised, carbonyl-functionalised, amine-functionalised, amide-functionalised, pyrrole-functionalised, pyridine-functionalised, nitrogen functionalised, silane functionalised, mercapto-functionalised, vinyl-functionalised or halogen-functionalised and preferably wherein the shoe sole further comprises sulphur as a cross-linking agent.

The shoe sole according to any one of the preceding claims, wherein the functionalised carbon nanoparticles have nitrogen-containing, such as pyrrole, pyridine, amine, or amino, or carbonyl, aldehyde, alcohol, ketone;

• silane, mercapto, epoxy, vinyl, alkyl or fluoro functional groups on their surfaces and preferably wherein the shoe sole further comprises sulphur as a cross-linking agent.

The shoe sole according to any one of the preceding claims, wherein the carbon nanoparticles are not graphene oxide, or are not oxygen-functionalised.

The shoe sole according to any one of the preceding claims further comprising an additional filler and optionally, wherein the additional filler is silica.

The shoe sole according to any one of the preceding claims, wherein the rubber matrix material further comprises a non-butadiene elastomer, preferably wherein the non-butadiene elastomer is a thermoplastic urethane elastomer and/or ethylene vinyl acetate.

The shoe sole according to any one of the preceding claims, further comprising a plasticiser, preferably wherein the plasticiser is a mineral oil.

The shoe sole according to any one of the preceding claims, further comprising a lubricating agent, preferably wherein the lubricating agent is polyethylene glycol.