Systems and methods use polyacrylamide gel to resist corrosion of one or more wellhead components in a well cellar. Examples of such wellhead components include a surface casing and a landing base. The well cellar is part of a well, such as an oil well, a gas well or a water well.

Systems and methods use polyacrylamide gel to resist corrosion of one or more wellhead components in a well cellar. Examples of such wellhead components include a surface casing and a landing base. The well cellar is part of a well, such as an oil well, a gas well or a water well.

The present invention describes a method for the production of a spinning dope composition, said method comprising a homogenization involving vigorous mixing of a cellulosic pulp material in alkali solution, vigorous mixing implying supplying a power density to agitators used in the homogenization step of at least 150 kW/m.sup.3 (kW supplied to agitators per mixed unit of liquid volume), and thereafter a dissolution involving mixing of the cellulosic pulp material in the alkali solution to obtain a spinning dope composition, wherein the power density supplied to agitators used in the dissolution step is maximum 75 kW/m.sup.3 (kW supplied to agitators per mixed unit of liquid volume); and wherein the cellulosic pulp material in alkali solution is kept at a temperature of less than 0° C. during the homogenization and during at least part of the dissolution. The present invention is also directed to a system intended for the production of a spinning dope composition.

The present invention describes a method for the production of a spinning dope composition, said method comprising a homogenization involving vigorous mixing of a cellulosic pulp material in alkali solution, vigorous mixing implying supplying a power density to agitators used in the homogenization step of at least 150 kW/m.sup.3 (kW supplied to agitators per mixed unit of liquid volume), and thereafter a dissolution involving mixing of the cellulosic pulp material in the alkali solution to obtain a spinning dope composition, wherein the power density supplied to agitators used in the dissolution step is maximum 75 kW/m.sup.3 (kW supplied to agitators per mixed unit of liquid volume); and wherein the cellulosic pulp material in alkali solution is kept at a temperature of less than 0° C. during the homogenization and during at least part of the dissolution. The present invention is also directed to a system intended for the production of a spinning dope composition.

A method for preparing a high-temperature self-crosslinking aqueous polyurethane dispersion. By using isocyanate (NCO) blocking agent to block part of the NCO, and using the hydroxyalkyl ethylenediamine chain extender in the post-chain extension stage to introduce hydroxyl groups, the polymer macromolecular structure containing both blocked NCO groups and hydroxyl groups can be prepared. The aqueous polyurethane dispersion does not need to mix with other waterborne resins and crosslinkers when applied. A sufficient cross-linking reaction is performed between the NCO released and hydroxyl groups on the polymer macromolecular chain to form a high-density cross-linked structure when curing at 100-150° C. for 20-30 min, thus obtaining a high-performance waterborne coating that can be used in the form of one-pack.

A method for preparing a high-temperature self-crosslinking aqueous polyurethane dispersion. By using isocyanate (NCO) blocking agent to block part of the NCO, and using the hydroxyalkyl ethylenediamine chain extender in the post-chain extension stage to introduce hydroxyl groups, the polymer macromolecular structure containing both blocked NCO groups and hydroxyl groups can be prepared. The aqueous polyurethane dispersion does not need to mix with other waterborne resins and crosslinkers when applied. A sufficient cross-linking reaction is performed between the NCO released and hydroxyl groups on the polymer macromolecular chain to form a high-density cross-linked structure when curing at 100-150° C. for 20-30 min, thus obtaining a high-performance waterborne coating that can be used in the form of one-pack.

The present disclosure describes a method for the production of a spinning dope composition, said method comprising a homogenization involving mixing a cellulosic pulp material in alkali solution, mixing implying supplying a power density to agitators used in the homogenization of at least 150 kW/m.sup.3 (kW supplied to agitators per mixed unit of liquid volume), and thereafter a dissolution involving mixing of the cellulosic pulp material in the alkali solution to obtain a spinning dope composition, wherein the power density supplied to agitators used in the dissolution step is maximum 75 kW/m.sup.3 (kW supplied to agitators per mixed unit of liquid volume); and wherein the cellulosic pulp material in alkali solution is kept at a temperature of less than 0° C. during the homogenization and during at least part of the dissolution. The present disclosure is also directed to a system intended for the production of a spinning dope composition.

The present disclosure describes a method for the production of a spinning dope composition, said method comprising a homogenization involving mixing a cellulosic pulp material in alkali solution, mixing implying supplying a power density to agitators used in the homogenization of at least 150 kW/m.sup.3 (kW supplied to agitators per mixed unit of liquid volume), and thereafter a dissolution involving mixing of the cellulosic pulp material in the alkali solution to obtain a spinning dope composition, wherein the power density supplied to agitators used in the dissolution step is maximum 75 kW/m.sup.3 (kW supplied to agitators per mixed unit of liquid volume); and wherein the cellulosic pulp material in alkali solution is kept at a temperature of less than 0° C. during the homogenization and during at least part of the dissolution. The present disclosure is also directed to a system intended for the production of a spinning dope composition.

To provide a method for producing an aqueous polytetrafluoroethylene dispersion, whereby the formation of fluorinated oligomers as byproducts is minimized, CFT of the formed coating film is large, and a highly concentrated aqueous polytetrafluoroethylene dispersion is easily obtainable. The method for producing an aqueous polytetrafluoroethylene dispersion, which comprises step A1 of polymerizing a non-fluorinated monomer in an aqueous medium to obtain a solution 1 containing a polymer containing units based on the non-fluorinated monomer, step A2 of conducting polymerization of tetrafluoroethylene in the solution 1 without substantially adding a surfactant to the solution 1, to obtain an aqueous emulsion containing polytetrafluoroethylene particles, and step A3 of adding a nonionic surfactant to the aqueous emulsion at a rate of from 10 to 150 mass % to the mass of PTFE contained in the aqueous emulsion, and subsequently concentrating the aqueous emulsion to obtain an aqueous polytetrafluoroethylene dispersion, wherein the amount of the non-fluorinated monomer used, to the amount of the tetrafluoroethylene supplied to the polymerization system, is at most 200 mass ppm.

To provide a method for producing an aqueous polytetrafluoroethylene dispersion, whereby the formation of fluorinated oligomers as byproducts is minimized, CFT of the formed coating film is large, and a highly concentrated aqueous polytetrafluoroethylene dispersion is easily obtainable. The method for producing an aqueous polytetrafluoroethylene dispersion, which comprises step A1 of polymerizing a non-fluorinated monomer in an aqueous medium to obtain a solution 1 containing a polymer containing units based on the non-fluorinated monomer, step A2 of conducting polymerization of tetrafluoroethylene in the solution 1 without substantially adding a surfactant to the solution 1, to obtain an aqueous emulsion containing polytetrafluoroethylene particles, and step A3 of adding a nonionic surfactant to the aqueous emulsion at a rate of from 10 to 150 mass % to the mass of PTFE contained in the aqueous emulsion, and subsequently concentrating the aqueous emulsion to obtain an aqueous polytetrafluoroethylene dispersion, wherein the amount of the non-fluorinated monomer used, to the amount of the tetrafluoroethylene supplied to the polymerization system, is at most 200 mass ppm.