Urethane-based adhesive composition
A urethane-based adhesive composition includes a urethane prepolymer, a carbon black A having a dibutyl phthalate oil absorption number of 30 to 40 ml/100 g, a carbon black B having a dibutyl phthalate oil absorption number of 98 to 108 ml/100 g, a calcium carbonate C, a plasticizer D, a modified product E of an aliphatic diisocyanate, and a catalyst, and the urethane-based adhesive composition is configured to satisfy all of the following (1) to (6): (1) 25≤a≤35, (2) 55≤b≤75, (3) 197≤a+3b≤251, (4) 30≤c≤35, (5) 35≤d≤45, and (6) 9≤e≤13.
1 . A urethane-based adhesive composition comprising:
a urethane prepolymer;
a carbon black A having a dibutyl phthalate oil absorption number of 30 to 40 ml/100 g;
a carbon black B having a dibutyl phthalate oil absorption number of 98 to 108 ml/100 g;
a calcium carbonate C;
a plasticizer D;
a modified product E of an aliphatic diisocyanate; and
a catalyst,
the urethane-based adhesive composition being configured to satisfy all of the following (1) to (6):
25≤ a≤ 35 (1)
55≤ b≤ 75 (2)
197≤ a+ 3 b≤ 251 (3)
32≤ c< 35 (4)
35≤ d≤ 45 (5)
9≤ e≤ 13 (6)
where “a” in the (1) and (3) represents a content of the carbon black A with respect to 100 parts by mass of the urethane prepolymer,
“b” in the (2) and (3) represents a content of the carbon black B with respect to 100 parts by mass of the urethane prepolymer,
“c” in the (4) represents a content of the calcium carbonate C with respect to 100 parts by mass of the urethane prepolymer,
“d” in the (5) represents a content of the plasticizer D with respect to 100 parts by mass of the urethane prepolymer,
“e” in the (6) represents a content of the modified product E with respect to 100 parts by mass of the urethane prepolymer, and
units of the “a” to “e” are parts by mass.
2 . The urethane-based adhesive composition according to claim 1 , wherein the modified product E contains a biuret of hexamethylene diisocyanate and/or an isocyanurate of hexamethylene diisocyanate.
3 . The urethane-based adhesive composition according to claim 1 , wherein the calcium carbonate C contains heavy calcium carbonate.
4 . The urethane-based adhesive composition according to claim 1 , wherein the plasticizer D contains a phthalic acid ester and/or an adipic acid ester.