Adhesive composition and rubber reinforcing material

An adhesive composition comprising a latex (A), a polyurethane (B), an amine-based adhesion promoter (C), and a water-containing solvent (G),

• wherein a relative viscosity of the adhesive composition measured at room temperature using an Ubbelohde viscometer satisfies the range of 2.50 to 3.00,
• wherein the composition further comprises an amine-based chain extender (D), wherein a weight (W1) of the amine-based adhesion promoter (C) is greater than a weight (W2) of the amine-based chain extender (D),
• wherein the composition contains 1.0% by weight or more of the amine-based adhesion promoter (C) based on the total weight of the composition,
• wherein a reference solvent used at the time of measuring the relative viscosity is water, wherein a weight ratio (Wi/W2) between the weight (W1) of the amine-based adhesion promoter (C) and the weight (W2) of the amine-based chain extender (D) is in the range of 2.0 to 10,
• wherein the amine-based adhesion promoter (C) is a reaction product of a fatty acid (C1) and an amine compound (C2),
• wherein the amine-based chain extender (D) is a primary, secondary, or tertiary amine that does not have a chain structure derived from a fatty acid and has a structure different from the amine-based adhesion promoter (C).