Patent

The green strength of polymers produced by emulsion polymerization processes is improved through the use of carboxyl containing compounds. Specifically, the compounds are half esters of unsaturated dicarboxylic acids wherein the half ester moiety renders the carboxyl containing compound hydrophobic. As a result, carboxylic copolymers can be produced in emulsion polymerizations having a basic (pH.gtoreq.7.0) aqueous medium. Heretofore, use of carboxylic acids in emulsion polymerizations have been limited to acidic mediums.

The present invention relates to toughened cyanoacrylate compositions.

This invention relates to adhesive compositions particularly adapted for forming flexible adhesive bonds and is particularly concerned with adhesive compositions comprising a mixture of at least two different esters of alpha-cyanoacrylic acid.

Disclosed are cyanoacrylate adhesive compositions containing elastomeric polymers as fillers. Preferred fillers are the acrylic rubbers. Filler concentration range from about 0.5-40% by weight of the composition. Beneficial results include improved toughness of the cured compositions, as measured by impact, peel and tensile strength properties, particularly after exposure elevated temperatures which would ordinarily severely degrade the adhesive strength.

An adhesive composition comprising a 2-cyanoacrylate and at least one member selected from the group consisting of substituted or unsubstituted aliphatic carboxylic acids having three or more carboxyl groups, anhydrides thereof, partial esters thereof, aromatic polycarboxylic acids having three or more carboxyl groups and anhydrides thereof. This composition has a high impact strength, is suitable for bonding metallic substrates to one another and is also excellent in resistance to heat, weather, and water.

An instant-setting adhesive composition comprising a 2-cyanoacrylate and at least one 1,1-disubstituted diene, the amount of said 1,1-disubstituted diene exceeding 50% by weight based on the total weight of both components. This composition is useful in the same fields as those where conventional 2-cyanoacrylate adhesives have been used, and is excellent in impact resistance, peel resistance, heat resistance and water resistance.

An adhesive composition comprises (a) at least one polymerizable cyanoacrylate monomer, (b) 0.1 to 10% by weight of a polymerizable acrylate ester e.g. allyl methacrylate and (c) 0.1 to 20% by weight of a maleimide derivative of formula wherein R<7> and R<8> are from alkyl, cycloalkyl, aralkyl or arkaryl. The compositions may polymerize with ring-opening of the maleimide. They have excellent hot strength properties for long periods at 121 DEG C (250 DEG F) or more.

Cyanoacrylate adhesive compositions containing (a) a toughener (e.g., a core-shell copolymer such as an MBS, ABS, or MABS copolymer), the toughener optionally being treated to remove impurities which cause premature polymerization of cyanoacrylates, and (b) cyanoacrylate-compatible, toughener-compatible sustainer (e.g., an organic compound containing one or more unsubstituted or substituted aryl groups, such as diphenylmethane or dichlorobenzene). The inclusion of sustainer provides improved retention of toughness after heat aging of cured bonds of the adhesive.

A composition comprising of a monomer component comprised of an alkyl cyanoacrylate and at least one inhibitor, and a second component comprised of a resultant aggregate structure formed from an alkyl cyanoacrylate monomer, an alkyl esterified fatty acid and an opacificant agent where said composition forms a resultant aggregate structure when said composition contacts an anionic environment.