Solvent-based adhesive composition for roofing membranes

A solvent-based adhesive composition for adhering together roofing materials comprising:

• a) from about 5% to about 30% by weight of a halogenated copolymer of isobutylene and p-methyl styrene;
• b) from about 3% to about 20% by weight of a thermoplastic rubber;
• c) from about 0.1% to about 15% by weight of an endblock resin for said thermoplastic rubber;
• d) from about 0.1% to about 15% by weight of a tackifier;
• e) from about 0.01 to about 5% of an accelerator/cure package including a sulfur and/or zinc oxide curing agent;
• and
• f) from about 60% to about 80% by weight of a solvent, whereupon curing said composition exhibits a peel strength of at least 3.0 pli at room temperature, at least 3.0 pli at 212.degree. F., supports a static load of at least 0.67 pounds at 158.degree. F., and exhibits a viscosity increase of less than 1500 centipoise after aging at 130.degree. l F. for six weeks.

A solvent-based adhesive composition for adhering together roofing materials comprising:

• a) from about 10% to about 14% by weight of a halogenated copolymer of isobutylene and p-methyl styrene;
• b) from about 5% to about 9% by weight of a thermoplastic rubber;
• c) from about 1% to about 3% by weight of an endblock resin for said thermoplastic rubber;
• d) from about 4% to about 8% by weight of a tackifier;
• e) from about 0.05% to about 2% of an accelerator/cure package including a sulfur and/or zinc oxide curing agent;
• f) from about 65% to about 75% by weight of a solvent;
• g) from about 0.01% to about 2% by weight of a reinforcing agent;
• h) from about 0.01% to about 2% by weight of an antioxidant;
• i) from about 0.2% to about 5% by weight of an antisettling agent;
• and
• j) from about 0.01% to about 2% by weight of an accelerator agent, whereupon curing said composition exhibits a peel strength of at least 3.0 pli at room temperature, at least 3.0 pli at 212.degree. F., supports a static load of at least 0.67 pounds at 158.degree. F. and exhibits a viscosity increase of less than 1500 centipoise after aging at 130.degree. F. for six weeks.

A method of making a solvent-based adhesive composition for adhering together roofing materials comprising the steps of:

• a) forming a homogeneous mixture of a halogenated copolymer of isobutylene and p-methyl styrene, a thermoplastic rubber, and an accelerator/cure package including a sulfur and/or zinc oxide curing agent;
• b) pelletizing said mixture;
• c) adding an endblock resin for said thermoplastic rubber, a tackifier, and a solvent to said mixture so as to form a slurry;
• and
• d) mixing said slurry until said mixture, said resin and said tackifier are completely solvated in said solvent.