Aqueous dispersions based on (meth)acrylic acid alkyl ester polymers with two pronounced, substantially non-overlapping peaks in the particle size distribution within specific particle size ranges, and a process for the preparation and use thereof

US4384056A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Adolf Schmidt · Adelsheim, DE
• Gunter Kolb · Leverkusen, DE
• Werner Clarenz · Leverkusen, DE

Key dates

• Filing date: Apr 28, 1981
• Grant date: May 17, 1983
• Expiry date: Apr 28, 2001

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08L2205/02
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Aqueous dispersions of polymers containing (meth)acrylic acid alkyl ester units which contain the polymer in the form of relatively large, non-agglomerated, spherical particles (=main spheres) and relatively small, non-agglomerated, spherical particles (=filler spheres), wherein the smaller filler spheres have an average particle diameter d.sub.F measured using an electron microscope of from 50 to 150 nanometers (nm) and the average diameter of the large main spheres d.sub.H is from 1.35 to 3.5 times larger than the average particle diameter d.sub.F, provided that d.sub.H is at least 140 nm, and wherein the ratio of the total mass of the polymer composed of main spheres M.sub.H to the total mass of the polymer composed of filler spheres M.sub.F is EQU M.sub.H :M.sub.F =20:1 to M.sub.H :M.sub.F =1:20 and wherein at least 70% of the number of main spheres and at least 70% of the number of filler spheres lie in the range of .+-.25% of the respective average value of d.sub.H or d.sub.F. Dispersions of this type dry to form clear, lustrous and waterproof films, even with a solids content of from 37 to 45% by weight, and even if that solids content has been obtained from more highly conc…