Compositions for removing contaminants from plastics processing equipment are described herein. The compositions may include a polymeric carrier component, an oxidizing agent, an abrasive and/or a gas agent. Methods of preparing the compositions described herein and methods of removing contaminants from plastics processing equipment are also described.

A process of cleaning a reactor includes providing an alcohol-containing material to the reactor; and providing a metathesis catalyst to the reactor. The reactor contains a high molecular weight polymer gel and an organoaluminum material. The alcohol-containing material is not an alkyl tartrate and may be selected from triisopropanolamine, 4-tert-butylcatechol, isopropanol, and phenol formaldehyde resins.

A substrate processing apparatus includes a processing container; a stage on which a substrate is placed, the stage being provided in the processing container; a gas supply provided at a position facing the stage and configured to supply a first processing gas containing a first monomer and a second processing gas containing a second monomer into the processing container to form a film of a polymer on the substrate; and a driver configured to move the stage so as to change a distance between the gas supply and the stage. The gas supply is configured to supply the first processing gas and the second processing gas into a space between the gas supply and the stage from an outside of a region on the stage in which the substrate is placed, when viewed in a direction from the gas supply toward the stage.

A polymerization reactor for producing aqueous polymer dispersions by radically initiated emulsion polymerization of one or more ethylenically unsaturated monomers in the presence of one or more protective colloids and/or emulsifiers, is cleaned by initially charging an aqueous mixture comprising one or more ethylenically unsaturated monomers, one or more protective colloids and/or emulsifiers, but no oxidation initiator, the proportion of ethylenically unsaturated monomers being 20 to 70% by weight of the aqueous mixture, heating the aqueous mixture to a temperature of 50? C. to 100? C. for 5 minutes to 3 hours, adding one or more initiators and optionally further starting materials, initiating polymerization, removing the aqueous polymer dispersion thus obtained from the polymerization reactor and post-treating the dispersion to remove wall deposits detached during the process.

Provided is a method of manufacturing an ethylene-acrylic acid copolymer including the step of (S1) supplying an ethylene monomer and an acrylic acid comonomer to a polymerization reactor to manufacture an ethylene-acrylic acid copolymer; (S2) supplying an acrylic acid comonomer-containing mixture discharged from a front or rear end of the polymerization reactor and a cleaning solvent to a cleaning unit; and (S3) dissolving an polyacrylic acid derived from the acrylic acid comonomer contained in the mixture in the cleaning solvent. The cleaning solvent includes a polyhydric alcohol-based solvent.

Provided is a method of manufacturing an ethylene-acrylic acid copolymer including the step of (S1) supplying an ethylene monomer and an acrylic acid comonomer to a polymerization reactor to manufacture an ethylene-acrylic acid copolymer; (S2) supplying an acrylic acid comonomer-containing mixture discharged from a front or rear end of the polymerization reactor and a cleaning solvent to a cleaning unit; and (S3) dissolving an polyacrylic acid derived from the acrylic acid comonomer contained in the mixture in the cleaning solvent. The cleaning solvent includes a polyhydric alcohol-based solvent.

A process for polymerizing or copolymerizing ethylene in a slurry polymerization in a reactor system including a polymerization reactor, one or more first heat exchangers located outside the polymerization reactor, and a closed loop of a tempering medium for cooling or heating the first heat exchangers, which closed loop is equipped with second heat exchangers for cooling the tempering medium and third heat exchangers for heating the tempering medium, and wherein, during the polymerization, the slurry is cooled in the first heat exchangers, the temperature of the tempering medium cooling the first heat exchangers is in the range from 20 C. to 50 C., and the tempering medium is cooled in the second heat exchangers by a coolant, having a temperature from 20 to 45 C.

A process for polymerizing or copolymerizing ethylene in a slurry polymerization in a reactor system including a polymerization reactor, one or more first heat exchangers located outside the polymerization reactor, and a closed loop of a tempering medium for cooling or heating the first heat exchangers, which closed loop is equipped with second heat exchangers for cooling the tempering medium and third heat exchangers for heating the tempering medium, and wherein, during the polymerization, the slurry is cooled in the first heat exchangers, the temperature of the tempering medium cooling the first heat exchangers is in the range from 20 C. to 50 C., and the tempering medium is cooled in the second heat exchangers by a coolant, having a temperature from 20 to 45 C.

Process for the polymerization or copolymerization of olefins by bringing the olefins into contact with a catalyst under polymerization or copolymerization conditions in a reactor containing a charge powder. The process includes, prior to introducing the catalyst into the reactor, introducing a scavenger into the reactor which reacts with catalyst poison present. The scavenger is added to the reactor until the charge powder contains a remaining amount of scavenger of between 0.1 and 2.5 moles per ton of charge powder.

The disclosure provides methods for removing polymeric fouling on process equipment during low density polyethylene manufacture. A purge cleaning composition with ethylene gas containing at least one C3+ hydrocarbon alkene for a period of time is used to remove polymer build-up in at least one location in the polymerization plant, such as, without limitation, the reactor or in tubing between a reactor and a pre-heater or between a cooler and a preheater.