Wacker-chemie Gmbh

Alfred Prasse

Herbert Eck

Gerald Fleischmann

Reinhard Jira

Hartmut Menzel

Kunigunde Kolbig

The invention provides biodegradable vinyl ester copolymers of one or more monomers selected from the group of vinyl esters of unbranched or branched alkylcarboxylic acids having from 1 to 18 carbon atoms, which contain from 0.1 to 40% by weight, based on the total weight of the copolymer, of one or more cyclic ketene acetals selected from the group consisting of 2-methylene-1,3-dioxepane, 2-methylene-1,3-dioxolane, 2-methylene-1,3-dioxane and have a molecular weight&gt;50,000.

Biodegradable vinyl ester copolymers

A process for polymerizing polar compounds which have a C.dbd.C double bond in an .alpha.-position relative to a carbonyl or nitrile group, such as acrylic acid derivatives, which comprises polymerizing the polar compounds in the presence of organometallic compounds of silicon, germanium or tin as initiators together with a nucleophilic or electrophilic catalyst at temperatures in the range of from -100.degree. C. to +100.degree. C. The initiators used in the quasi-ionic polymerization are selected from group (I) consisting of cyclic silazanes, polymeric silazanes which contain more than two silazanyl groups per molecule, cyclic siloxanes and polymeric siloxanes which contain more than two siloxanyl groups per molecule and at least one Si-bonded hydrogen atom and silanes having at least one Si-bonded N atom in the form of secondary or tertiary amido groups or at least one Si-bonded carbon atom in the form of alkynyl or cyclodienyl groups for each Si atom, or group (II) consisting of silanes having at least three silyl groups per molecule, germanes, stannanes or siloxanes, germoxanes or stannoxanes, in which at least one metal-bonded hydrocarbyloxy group is present for each metal atom.

Process for polymerizing polar compounds

A process for improving the adhesion of polymeric substances containing organic groups or composed of such groups to the surfaces of alkaline earth metal carbonates, which comprises applying an organic aprotic solvent solution containing at least one organosilicon compound having fluorine bonded directly to silicon and an average of not more than 1.8 SiC-bonded organic radicals per silicon atom to the surface of alkaline earth metal carbonates and removing the solvent before a polymeric substance containing organic groups is applied to the pretreated alkaline earth metal carbonate surface.

Process for improving the adhesion of polymeric substances

Organosilicon compounds containing SiC-bonded biuret groups are prepared by (I) adding a silane containing 1 or 2 silicon atoms per molecule and an SiC-bonded organic radical having at least one basic ##STR1## group and at least one SiOC-bonded aliphatic radical per molecule to a monoisocyanate or a diisocycanate at a temperature up to 125.degree. C. and (II) maintaining the temperature at 110.degree. C. to 125.degree. C. for at least two minutes. In an alternate procedure the silane and mono- or diisocyanate may be heated to a temperature in the range of from 110.degree. C. up to 200.degree. C. for at least two minutes, after or while adding additional monoisocyanate or diisocyanate. The resultant silicon compounds are used in the preparation of polyurethanes and as additives to lacquers.

Silicon compounds containing SiC-bonded biuret groups and a method for

Organosilicon compounds containing SiC-bonded biuret groups are prepared by (I) adding a silane containing 1 or 2 silicon atoms per molecule and an SiC-bonded organic radical having at least one basic ##STR1## group and at least one SiOC-bonded aliphatic radical per molecule to a monoisocyanate or a diisocyanate at a temperature up to 125.degree. C. and (II) maintaining the temperature at 110.degree. C. to 125.degree. C. for at least two minutes. In an alternate procedure the silane and mono- or diisocyanate may be heated to a temperature in the range of from 110.degree. C. up to 200.degree. C. for at least two minutes, after or while adding additional monoisocyanate or diisocyanate. The resultant silicon compounds are used in the preparation of polyurethanes and as additives to lacquers.

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Burghausen, Germany

Alfred Prasse