Acid-modified polyhydric alcohol rosin ester tackifiers and hot melt adhesive compositions containing those tackifiers

A hot melt adhesive composition, comprising:

• (a) from about 10 to 75 weight percent of at least one of an ethylenic copolymer and styrenic block copolymer selected from the group consisting of ethylene-vinyl acetate, styrene-butadiene-styrene, styreneisoprene-styrene, and styrene-ethylenebutylene-styrene;
• (b) from about 0 to 50 weight percent of at least one of an oil selected from the group consisting of mineral oil, vegetable oil, animal oil and olefin oligomers, and a wax selected from the group consisting of mineral, animal and vegetable wax;
• and
• (c) from about 10 to 60 weight percent of an acid-modified rosin ester tackifier, said tackifier comprising:
• from about 78 to 92 weight percent of a tall oil rosin,
• up to about 10 percent equivalent excess of pentaerythritol based on the weight of the rosin;
• and
• from about 1 to 8 weight percent of isophthalic acid.

An acid-modified rosin ester tackifier for use in hot melt adhesive compositions, comprising:

• (a) a rosin,
• (b) a polyhydric alcohol;
• and
• (c) an aromatic dibasic acid.

An acid modified rosin ester tackifier for use in hot melt adhesive compositions, comprising:

• (a) from about 78 to 92 weight percent of a tall oil rosin
• (b) up to about 10 percent equivalent excess of pentaerythritol, based on the weight of the tall oil rosin;
• and
• (c) from about 2 to 6 weight percent of isophthalic acid.