Sintef

Sinvent As

Life Technologies As

Other

Norskhydro Asa

Sintef (selskapet for Industriell Og Teknisk Forskning Ved Nth)

John Ugelstad

Arvid Trygve Berge

Turid Ellingsen

Geir Fonnum

Astrid Evenroed Molteberg

Elin Marie Aksnes

Ellen Weng

Rolf Nordal

Henning Pettersen

Solveig Staale

Finn Hansen

Oddvar Aune

Oskar B Helgee

Lars Kilaas

John W Vanderhoff

Steinar Pedersen

Mohamed S El-Aasser

Per Martin Stenstad

Tom-Nils Nilsen

Kari-Anne Leth-Olsen

B&aring;rd S&aelig;thre

Harald Jacobsen

Tollef Taarneby

Arne Jørgedal

Silje Nordbø

John Bjørgum

Arne Jorgedal

Silje Nordbo

Tollef Tårneby

John Bjorgum

Jon-Olav Bjo Slashedrgum

A process for the preparation of monodisperse polymer particles which are formed by contacting monomers with aqueous dispersions comprising monodisperse swellable seed polymers/oligomers, and initiating polymerization in the presence of a steric stabilizer. The resulting swollen seed particles are characterized by the particle mode diameter.

Process for the preparation of monodisperse polymer particles

A procedure for the production of PVC particles with a narrow size distribution in the range 10-50 &mgr;m, preferably 10-30 &mgr;m, in which, in a first stage, a vinyl monomer or a mixture of monomers is polymerised to form a polymer/oligomer seed particle in the range 1-10 &mgr;m. In a second stage, another vinyl monomer or mixture of monomers is swelled into the polymer/oligomer seed particles and polymerisation takes place in such a way that they grow into polymer particles of the desired size. It is preferable to use aromatic vinyl monomers or acrylates as the monomer in the seed particles. The seed particles in the first stage can be produced in a two-stage swelling process or by dispersion polymerisation.

Two-stage seed swelling procedure for producing monodisperse PVC particles

Immobilization and separation of cells and other particles

Process for preparing a dispersion and for preparing polymer particles

Magnetic polymer particles prepared by treating compact or porous polymer particles with a solution of iron salts and, if desired, salts of other metals which are capable of forming magnetic ferrites, in which the solution swells or penetrates into the particles. Iron hydroxide and possible other metal hydroxides are precipitated, for instance by raising the pH value, and the particles are optionally heated. In the iron salts used the ratio between di- and trivalent iron is suitably such that magnetic iron oxide is formed directly. It is also possible to use oxidizing or reducing groups or additives to obtain such a ratio. When other metal salts are used in addition to iron salts, the operation is carried out in the same manner. For instance, when Mn.sup.++, Co.sup.++ or Ni.sup.++ salts are used in addition to Fe.sup.++ salts, the divalent iron is oxidized to trivalent so that magnetic ferrite is obtained. The polymer particles which are treated with metal salts preferably contain metal-binding groups. Such groups are incorporated for instance by using monomers which contain said groups for the preparation of the polymer particles, or the groups are incorporated in the polymer particles prepared. The magnetic polymer particles are spherical and have a uniform concentration of magnetic material. They may be used for medical, diagnostic or other purposes.

Process for preparing magnetic polymer particles

Magnetic polymer particles and process for the preparation thereof

The invention provides a process for the preparation of polymer latex by emulsification of an initiator or initiator mixture and optionally a solvent in the presence of emulsifier in water in a first step and adding a monomer and polymerizing in a second step. The process is carried out by emulsifying an essentially water-insoluble initiator or initiator mixture in the first step at a temperature above the melting point of the initiator or initiator mixture if no solvent is used, and below its decomposition temperature, optionally together with an essentially water-insoluble liquid solvent, which forms a liquid solution together with the initiator or the initiator mixture at the emulsification temperature, then, in a second step adding monomer, possibly additional emulsifier and that part of the desired amount of water which was not added in the first step, and initiating polymerization as per se known by heating.

Process for the preparation of polymer latex

Process for the preparation of aqueous dispersions of organic material

The invention provides monodisperse polymer particles and dispersions thereof, said particles having a diameter of preferably 5 .mu.m or more. Such polymer dispersions are prepared by in a first step preparing a dispersion of smaller monodisperse polymer particles containing one or more materials having a very low solubility in water, and a relatively low molecular weight, then in a second step adding a partly water-soluble monomer which diffuses into the particles from the first step, and then effecting polymerization.

Monodisperse polymer particles and dispersions thereof

The invention provides a process for preparing an aqueous emulsion or dispersion of a partly water-soluble material, and optionally further conversion of the prepared dispersion or emulsion to a polymer dispersion when the partly water-soluble material is a polymerizable monomer. In a first step a dispersion of polymer particles is prepared containing one or more materials having a very low solubility in water, then in a second step there is added the partly water-soluble material which diffuses into the particles from the first step, and then, if the partly water-soluble material is a polymerizable monomer, polymerization may be effected.

Process for preparing an aqueous emulsion or dispersion of a partly

Process for producing finely divided aqueous emulsions from materials of ited water solubility. These materials are diffused into pre-formed particles dispersed in water which are formed from vinyl compounds by emulsion polymerization under conditions which cause the pre-formed seed latex to include in the particles 10-100 percent oligomers having a molecular weght of 200-10,000. These seed particles take up 20-500 times their own volume of the material of limited water solubility.

Process for producing finely divided aqueous emulsions from materials of

A polymer emulsification process comprising intimately dispersing a liquified water insoluble polymer phase in an aqueous liquid medium phase containing at least one nonionic, anionic or cationic oil-in-water functioning emulsifying agent, in the presence of a compound selected from the group consisting of those hydrocarbons and hydrocarbyl alcohols, ethers, alcohol esters, amines, halides and carboxylic acid esters which are inert, non-volatile, water insoluble, liquid and contain a terminal aliphatic hydrocarbyl group of at least about 8 carbon atoms, and mixtures thereof, and subjecting the resulting crude emulsion to the action of comminuting forces sufficient to enable the production of an aqueous emulsion containing polymer particles averaging less than about 0.5 .mu. in size.

Polymer emulsification process

A process for preparing a latex by efficiently homogenizing an aqueous mixture containing an emulsifier and a water-insoluble solvent for the monomer(s) to be polymerized, adding monomer and if desired further water to the homogenized mixture and also a water-soluble polymerization initiator. Instead of a water-soluble polymerization initiator an oil-soluble polymerization may be used having sufficient solubility to diffuse through the aqueous phase into the drops of water-insoluble solvent and monomer.

Process for preparing latex

Growing community of inventors

Trondheim, Norway

John Ugelstad