Pressure-sensitive adhesives for polyolefin surfaces

A method for producing a pressure-sensitive adhesive comprising providing starting materials comprising:

• (a) 50 to 100 parts by weight of at least one acrylic or methacrylic ester of a non-tertiary alkyl alcohol in which the alkyl group contains 2 to 20 carbon atoms;
• (b) 0 to 50 parts by weight of at least one reinforcing monomer, copolymerizable with component (a), the sum of (a) and (b) amounting to 100 parts by weight;
• and
• (c) 0.1 to 15 parts by weight, per 100 parts by weight of the sum of components (a) and (b), of a substantially soluble chlorinated polyolefin;
• said starting materials being substantially solvent-free;
• and polymerizing said starting materials in a substantially solvent free process.

A method for producing a pressure sensitive adhesive comprising the steps of:

• (a) providing a monomer composition comprising:
• (i) 50 to 100 parts by weight of at least one acrylic or methacrylic ester of a non-tertiary alkyl alcohol in which the alkyl group contains 2 to 20 carbon atoms;
• and
• (ii) 0 to 50 parts by weight of at least one reinforcing monomer copolymerizable with component (i), the sum of (i) and (ii) amounting to 100 parts by weight,
• (b) optionally polymerizing said monomer composition to form a syrup;
• (c) dissolving a substantially soluble chlorinated polyolefin selected from the group consisting of chlorinated polypropylene and chlorinated ethylene vinyl acetate in said monomer composition or said syrup to form a solution;
• and
• (d) polymerizing said solution to form an adhesive, wherein the polymerization is performed by a substantially solvent-free process.

A pressure sensitive adhesive comprising the polymerization reaction products of an adhesive composition consisting essentially of the following components:

• (a) 50 to 100 parts by weight of at least one acrylic or methacrylic ester of a non-tertiary alkyl alcohol in which the alkyl group contains 4 to 20 carbon atoms;
• (b) 0 to 50 parts by weight of at least one reinforcing monomer, copolymerizable with component (a), the sum of (a) and (b) amounting to 100 parts by weight;
• (c) 0.1 to 15 parts by weight, per 100 parts by weight of the sum of components (a) and (b), of a chlorinated polypropylene characterized as being substantially soluble in the (a) and (b) components;
• (d) an effective amount of a free radical initiator;
• (e) an effective amount of a crosslinking agent;
• and
• (f) optionally, a tackifier,
• said adhesive composition being substantially solvent free and wherein (i) said pressure sensitive adhesive exhibits adhesion build to a thermoplastic olefin surface at 70.degree. C. and (ii) the polymerization is performed by a substantially solvent-free process.