English

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.

Three different types of ion-supported TEMPO catalysts are synthesized and their catalytic activity in the chemoselective oxidation of alcohols is investigated. These new catalysts show high catalytic activity in water and can be reused for the next run by extraction of products. Recycling experiments exhibit that ion-supported TEMPO can be reused up to five times without loss of catalytic activity. This system offers a very clean, convenient, environmentally benign method for the selective oxidation of alcohols.

A xanthate derived photoinitiator, S-methacryloyl O-ethyl xanthate (MAX) bearing an electron-deficient polymerizable double bond has been found to be capable of distinguishing MMA and styrene, thereby dictating their polymerization pathways in distinctly different and controlled fashion. The structure, molecular weight, and the polydispersity of each polymer have been determined by spectral analysis and size-exclusion chromatography (SEC).

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.

The problem addressed by the invention was to find an anionic polymerization inhibitor for cyanoacrylate adhesives containing one or more cyanoacrylates, stabilizers against anionic and radical polymerization and auxiliaries typically used in such adhesive systems which, besides a reliable inhibiting effect, would counteract any increase in the setting time after storage. This problem was solved by using 2-oxo-1,3,2-dioxathiolanes as inhibitors.

The successful use of 3-sulfolene as an alternative reagent for sulfur dioxide was demonstrated for the first time by two types of the reactions : i) deoxygenation of aromatic amine N-oxides and ii) isomerization of ergosterol and its derivatives.

An adhesive composition comprising 2-cyanoacrylate and at least one compound selected from the group consisting of R1-CH2OH,

pentafluorophenol, hexachloroacetone, hexachloroacetone hydrate, chloral and chloral hydrate as cationic-polymerization inhibitor. In the above formulas, R1 is a fluorinated alkyl or aryl group having up to 12 carbon atoms, and R2 and R3 are fluorinated or non-fluorinated alkyl or aryl groups having up to 12 carbon atoms. The above adhesive composition has an excellent storage stability and an improved bonding strength.

A method for producing a purified 2-cyanoacrylate is characterized in that distillation is conducted in the presence of a polymerization inhibitor whose boiling point is within ±12° C. of the boiling point of the 2-cyanoacrylate. With this method, polymerization of 2-cyanoacrylate can be continuously prevented in the distillate system during distillation of a crude 2-cyanoacrylate, so that a purified 2-cyanoacrylate can be obtained.

A curable cyanoacrylate adhesive composition intended for medical and/or veterinary uses is sterilized in liquid form by gamma irradiation. The composition comprises

a) a cyanoacrylate monomer

b) a combination of an anionic stabilizer in amounts effective to stabilize the composition during storage prior to cure, wherein the free radical stabilizer is a selected phenolic antioxidant (but not including hydroquinone).