Hybrid running track article and method for preparing the same

1 . A hybrid running track article, comprising, from top to bottom:

(I) a top coating layer made from a first composition comprising an externally emulsified polyurethane dispersion and rubber particles, wherein the externally emulsified polyurethane dispersion is derived from: (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups; (Ci) an optional catalyst, (Di) an external emulsifier, (Ei) a chain extender and (Fi) water, and

(II) a bottom layer made from a second composition comprising a 1K solvent-free polyurethane binder and rubber particles,

wherein the (Ei) chain extender is C 4 -C 15 cycloaliphatic polyamine comprising at least two amine groups within the aliphatic cycle, C 4 -C 15 cycloaliphatic polyamine comprising at least two amine groups outside the aliphatic cycle or a mixture thereof.

2 . The hybrid running track article of claim 1 , wherein the (Bi) isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups is a polyether polyol.

3 . The hybrid running track article of claim 1 , wherein the (Di) external emulsifier is selected from the group consisting of ethoxylated phenols; alkali metal fatty acid salts; alkali metal C12-C16alkyl sulfates; alkali metal C12-C16alkylbenzene sulfonates; anionic and nonionic fluorocarbon emulsifiers.

4 . The hybrid running track article of claim 1 , wherein the (Ei) chain extender is used at an amount to make sure that the NCO blocking ratio of the prepolymer is from about 70.0% to about 98.5%, wherein the prepolymer is prepared by (i) reacting (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups with (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups in the presence of (Ci) an optional catalyst.

5 . The hybrid running track article of claim 1 , wherein the 1K solvent-free polyurethane binder is moisture curable.

6 . The hybrid running track article of claim 1 , wherein the weight ratio of the externally emulsified polyurethane dispersion to the rubber particles is from 1:0.5˜1.5.

7 . The hybrid running track article of claim 1 , wherein the rubber particles are EPDM particles.

8 . A method for producing a hybrid running track article having, from top to bottom, a top coating layer made from a first composition and a bottom layer from a second composition, the method comprising:

i) applying the second composition comprising a 1K solvent-free polyurethane binder and rubber particles on the ground;

ii) curing the second composition to obtain the bottom layer;

iii) applying the first composition comprising an externally emulsified polyurethane dispersion and rubber particles, wherein the externally emulsified polyurethane dispersion is derived from: (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups; (Ci) an optional catalyst, (Di) an external emulsifier, (Ei) a chain extender and (Fi) water;

iv) drying the first composition to form the top coating layer on the bottom layer.

9 . A use of an externally emulsified polyurethane dispersion as a top coating layer of a running track article, wherein the externally emulsified polyurethane dispersion is derived from: (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups; (Ci) an optional catalyst, (Di) an external emulsifier, (Ei) a chain extender and (Fi) water, wherein the (Ei) chain extender is C 4 -C 15 cycloaliphatic polyamine comprising at least two amine groups within the aliphatic cycle, C 4 -C 15 cycloaliphatic polyamine comprising at least two amine groups outside the aliphatic cycle or a mixture thereof.