Ceskoslovenska Akademie Ved

Lubomir Lochmann

Jiri Trekoval

Jiri Coupek

Josef Babka

Theodor Kremlicka

The invention relates to a mixture for activation of polytetrafluoroethylene and other fluoroplastics for bonding by means of adhesives. The mixture contains an organometallic compound of an alkali metal stabilized against effects of atmospheric oxygen and humidity and is particularly suitable for the surface activation in a lot or continuous production or for spaceous articles, where the simple use without protective atmosphere is advantageous. It consists of 1-60 wt. % of an organic polymer (mol. wt. above 4000) obtained by polymerization of ethylene, C.sub.1 -C.sub.3 alkyl, phenyl, or C.sub.1 -C.sub.10 alkoxy substituted theylene, ethylene oxide or propylene oxide or a mixture of these polymers, 1 mol of Li, Na or K metal, 0.4-2 mol of a hydrocarbon containing 2-4 bonded, condensed or aneled aromatic nuclei, 500-5000 ml of a solvent from a group comprising aliphatic and cycloaliphatic ethers or polyethers, and, if it is required, up to 50 vol. % of an aromatic, aliphatic or cycloaliphatic hydrocarbon and/or up to 1 mol of the crown ether of the general formula ##STR1## where m + n = 2 to 10. The surfaces treated with this mixture give virtually the same strength of bonding as after treatment with known organometallic agents, but under much more convenient condition of handling and application.

Mixture containing an organometallic compound of alkali metal and being

The invention relates to anionic polymerization and copolymerization of methacrylate and acrylate esters and related polar monomers, e.g. acrylonitrile, by initiation with carboxylic acid esters formally substituted in the .alpha.-position with Li, Na, K, Rb or Cs and containing 3 - 30 C atoms in the straight or branched chain and 1 - 6 ester group in one molecule either alone or in the presence of C.sub.3 - C.sub.16 alkali metal alkoxide with the straight or branched chain. The polymerization or copolymerization is carried out at -80.degree. to +50.degree. C, advantageously at 20.degree. C and the molar ratios of monomers to .alpha.-metallo ester 10 to 1500 and alkoxide to .alpha.-metallo ester 0.5 to 80. Instead of the pure isolated .alpha.-metallo esters also a reaction mixture may be used which was prepared from the alkaline salt of substituted organic amide and non-metallated ester. Aliphatic, cycloaliphatic or aromatic hydrocarbons, organic ethers or their mixtures were used as solvents for both monomers and initiatora. The method is also suitable for preparation of block copolymers of the aforesaid monomers, if the second or further comonomer is always added after the completed polymerization of the preceding monomer and if the subsequent monomers are used either of the equal anionic polymerizability or in the sequence of their increasing anionic polymerizability.

Method for preparation of methacrylate and acrylate polymers and

Polymeric alkoxides based on hydroxyalkyl methacrylates consist of units ##EQU1## where X is the organic bivalent group with the straight or branched C.sub.2 --C.sub.20 chain and M is Li, Na or K. The polymer has advantageously a heterogeneous structure of a macroporous gel with the inner surface 0.5 - 500 m.sup.2 /g. Polymeric alkoxides are prepared by treatment of a homopolymer or copolymer containing hydroxyl groups with the necessary amount of an alkali metal organic compound dissolved in an aprotic solvent, to convert the hydroxyl groups. Alkyl, aralkyl or aryl C.sub.1 to C.sub.30 derivatives of Li, Na or K are used as the alkali metal organic compounds.

Polymeric alkoxides based on hydroxyalkyl methacrylates and a method for

The invention relates to new esters of carboxylic acids formally substituted in the alpha-position by sodium or potassium which have the formula

Growing community of inventors

Prague, Czechia

Lubomir Lochmann