Betaine copolymers with hydroxyalkylacrylates and hydroxyalkylmethacrylates

Abstract

Abstract Copolymers of carboxybetaines or sulfobetaines having the formula WHEREIN R1 is hydrogen or methyl; A is oxygen or -NH-; R2 is ethylene, propylene, 2-hydroxypropylene or 2-acetoxypropylene; R3 and R4 are alkyl; n1 is 1 to 4 and X is SO3 or CO2 ; and about 10 to about 95.0 per cent by weight of hydroxyethylacrylate, hydroxyethylmethacrylate, hydroxypropylacrylate, hydroxypropylmethacrylate, polyethylene glycol acrylate, polyethylene glycol methacrylate, polypropylene glycol acrylate, polypropylene glycol methacrylate, polyglycerolacrylate or polyglycerolmethacrylate are disclosed. These neutral, hydrophilic copolymers are useful as binders. This invention relates to selected copolymers comprising units derived from carboxybetaines or sulfobetaines and units derived from hydroxyalkyl acrylates/methacrylates, polyalkylene glycol acrylates/methacrylates or polyglycerol acrylates/methacrylates. More particularly, this invention relates to neutral, hydrophilic copolymers of monomers consisting essentially of about 5.0 to about 90 percent by weight of a carboxybetaine or sulfobetaine having the formula WHEREIN R1 is hydrogen or methyl; A is oxygen or -NH-; R2 is ethylene, propylene, 2-hydroxypropylene or 2-acetoxyproplene; R3 and R4 are alkyl; n1 is 1 to 4 and X is SO3 or CO2 ; and about 10 to about 95.0 per cent by weight of hydroxyethylacrylate, hydroxyethylmethacrylate, hydroxypropylacrylate, hydroxypropylmethacrylate, or a polyalkylene glycol acrylate/methacrylate or polyglycerol acrylate/methacrylate having the formula WHEREIN R'' is hydrogen or methyl, R'''' is hydrogen, methyl or hydroxyl, n2 is zero where R'''' is hydrogen or methyl and 1 where R'''' is hydroxyl, and n3 is 2 to 4. Various carboxybetaines, sulfobetaines, homopolymers and copolymers thereof have been reported in the literature. Thus, U.S. Pat. Nos. 3,473,998 and 3,478,001 disclose sulfobetaines having the formula I and copolymers thereof with acrylonitrile, while U.S. Pat. No. 3,497,482 describes homopolymers of these sulfobetaines and copolymers with certain ethylenically unsaturated monomers. The carboxybetaines having the formula I, homopolymers thereof and copolymers with various ethylenically unsaturated compounds are reported in U.S. Pat. Nos. 2,777,872; 2,935,493 and 2,958,682. Now it has been found that copolymers of carboxybetaines and sulfobetaines with hydroxyalkylacrylates and hydroxyalkylmethacrylates can be provided according to this invention. These copolymers are particularly valuable as hydrophilic bonding agents for glass, leather, plastics, steel, hides and wood. The carboxybetaine and sulfobetaine monomers I can be conveniently prepared by reacting the appropriate Ndialkylaminoalkylacrylate/methacrylate or Ndialkylaminoalkylacrylamide/methacrylamide with a halomonocarboxylic (or sulfonic) acid salt or an alkyl lactone or sultone Following the procedure described in U.S. Pat. No. 2,744,130. Preparation of the copolymers of this invention is effected by polymerizing the carboxybetaine or sulfobetaine I or mixtures thereof, with hydroxyethylacrylate/methacrylate, hydroxypropylacrylate/methacrylate, polyethylene glycol acrylate/methacrylate, polypropylene glycol acrylate/methacrylate, polyglycerol acrylate/methacrylate, or mixtures thereof, the proportion of monomers being within the aforementioned range. The polymerization can be initiated by ultraviolet irradiation, heat, redox systems, peroxides, 2,2''azobis-isobutyronitrile or other suitable means. Preferably, the polymerization is carried out in aqueous or organic solvent solutions at a temperature of from about room temperature to 100* C. Although any of the copolymers can be conveniently prepared, preferred copolymers are those of carboxybetaine or sulfobetaine I wherein R3 and R4 are alkyl having one to four carbon atoms with hydroxyethylacrylate/methacrylate or hydroxypropylacrylate/methacrylate. While not essential to the preparation of the copolymers of this invention, minor amounts, for example up to 10.0 percent by weight of the total monomer charge, of an appropriate crosslinking agent can be utilized. Thus, ethylene glycol dimethacrylate, polyethylene oxide dimethacrylate, N-methylol acrylamide, glycidyl methacrylate, etc. can be suitably employed as crosslinking agents. The copolymers of this invention are useful as hydrophilic binders for a variety of materials, having advantages for these applications over their respective homopolymers and over various copolymers of betaines with other ethylenically unsaturated monomers. Thus, for example, the adhesion of these copolymers to various substrates is better than that of the corresponding polysulfobetaine and polycarboxybetaine homopolymers. These copolymers have increased breaking strength over homopolymers of hydroxyalkylacrylates, thus rendering them highly attractive for use as binders in applications where strength is important, such as in the production of certain non-wovens.

Inventors

• 👤 Carlos M Samour
• 👤 Martin L Falxa

Bibliographic Details