Rubber composition for tire tread, and pneumatic tire using same

1. A rubber composition for a tire tread comprising:

a diene rubber;

a silica;

a sulfur-containing silane coupling agent;

an alkyl triethoxysilane represented by Formula (I); and

a terpene resin;

a content of the silica being from 60 to 200 parts by mass per 100 parts by mass of the diene rubber,

the sulfur-containing silane coupling agent being a polysiloxane represented by the following Formula (1);

a content of the sulfur-containing silane coupling agent being from 1 to 20 mass % relative to the content of the silica, and

a content of the alkyl triethoxysilane being from 0.2 to 20 mass % of the content of the silica;

(A) a (B) b (C) c (D) d (R 1 ) e SiO (4-2a-b-c-d-e)/2   (1)

wherein Formula (1) is an average composition formula, and in Formula (1), A is a divalent organic group containing a sulfide group; B is a monovalent hydrocarbon group having from 5 to 10 carbon atoms; C is a hydrolyzable group; D is an organic group containing a mercapto group; R 1 is a monovalent hydrocarbon group having from 1 to 4 carbon atoms; and a to e satisfy the relational expressions 0≦a<1, 0≦b<1, 0<c<3, 0<d<1, 0≦e<2, and 0<2a+b+c+d+e<4; however, either a or b is not 0;

wherein in Formula (I), R is an alkyl group having from 7 to 20 carbon atoms,

wherein an amount of the terpene resin is from 1 to 30 parts by mass per 100 parts by mass of the diene rubber, and the terpene resin is an aromatic modified terpene resin having a softening point of from 60 to 150° C.

2. The rubber composition for a tire tread according to claim 1 , wherein b is greater than 0 in Formula (1).

3. A pneumatic tire having tire treads formed using the rubber composition for a tire tread described in claim 1 .