A prepolymer of elastomer material for screw drilling tools and a preparation method thereof are provided. The prepolymer includes component A and component B, wherein the component A includes hydroxyl-terminated liquid rubber, polytetrahydrofuran diol, and polyether polyol; the component B includes at least one of an isocyanate, a cyanate, and a cyano compound; the mass ratio of the hydroxyl-terminated liquid rubber, polytetrahydrofuran diol, and polyether polyol is (0.2-1.0): (0.2-1.0): (0.2-1.0). Different molecular segments of different proportions are introduced through structural design, such that the molecular structure of the prepolymer has both rigid and flexible segments, thus to achieve an adjustable and controllable structure of the prepolymer; and the introduction of active groups makes the prepolymer to show good reactivity and processability. Therefore, a reactive elastomer material having excellent properties such as hardness, tear strength, and tensile strength can be obtained used as an elastomer material for screw drilling tools.

A method of producing a polyurethane or polyisocyanurate foam is provided which involves the use of a specific combination of hydrofluoroolefin blowing agents and cell nucleators. The resulting foams have excellent long term thermal insulating performance and have reduced thickness in comparison to conventional thermal insulating boards. The rigid polyurethane and polyisocyanurate boards may be used to insulate refrigeration bodies, such as those employed in vehicles comprising refrigeration units, and cold storage containers.

A method of producing a polyurethane or polyisocyanurate foam is provided which involves the use of a specific combination of hydrofluoroolefin blowing agents and cell nucleators. The resulting foams have excellent long term thermal insulating performance and have reduced thickness in comparison to conventional thermal insulating boards. The rigid polyurethane and polyisocyanurate boards may be used to insulate refrigeration bodies, such as those employed in vehicles comprising refrigeration units, and cold storage containers.

The invention provides a polishing pad suitable for polishing at least one of semiconductor, optical, magnetic or electromechanical substrates. It includes a polyurea polishing layer and a polyurea matrix. The polyurea has a soft segment being a copolymer of aliphatic fluorine-free polymer groups and a fluorocarbon having a length of a least six carbons. The polyurea matrix being cured with a curative agent and including gas or liquid-filled polymeric microelements. The polyurea matrix has a bulk region and a transition region adjacent the bulk region that extends to the polishing layer. The polymeric microelements in the transition region decrease in thickness as they approach the polishing layer with thickness of the compressed microelements adjacent the polishing layer being less than fifty percent of a diameter of the polymeric microelements in the bulk region. The polishing layer remains hydrophilic during polishing in shear conditions.

The invention provides a polishing pad suitable for polishing at least one of semiconductor, optical, magnetic or electromechanical substrates. It includes a polyurea polishing layer and a polyurea matrix. The polyurea has a soft segment being a copolymer of aliphatic fluorine-free polymer groups and a fluorocarbon having a length of a least six carbons. The polyurea matrix being cured with a curative agent and including gas or liquid-filled polymeric microelements. The polyurea matrix has a bulk region and a transition region adjacent the bulk region that extends to the polishing layer. The polymeric microelements in the transition region decrease in thickness as they approach the polishing layer with thickness of the compressed microelements adjacent the polishing layer being less than fifty percent of a diameter of the polymeric microelements in the bulk region. The polishing layer remains hydrophilic during polishing in shear conditions.

The present invention provides coated films and packages formed from such films. In one aspect, a partially coated film comprises (a) a film having two outer surfaces, wherein a first outer surface is provided by a film layer that comprises from 70 to 100 percent by weight of a polyolefin having a density of 0.860 to 0.965 g/cm.sup.3; and (b) a coating on the first outer surface of the film comprising polyurethane, wherein the coating covers less than 25% of the surface area of the first outer surface of the film and wherein the coated portion of the film exhibits an Elmendorf tear in at least one of the machine direction or cross direction that is at least 20% less than the Elmendorf tear of the uncoated portion in the same direction, with the Elmendorf tear being measured in accordance with ASTM D1922.

The present invention provides coated films and packages formed from such films. In one aspect, a partially coated film comprises (a) a film having two outer surfaces, wherein a first outer surface is provided by a film layer that comprises from 70 to 100 percent by weight of a polyolefin having a density of 0.860 to 0.965 g/cm.sup.3; and (b) a coating on the first outer surface of the film comprising polyurethane, wherein the coating covers less than 25% of the surface area of the first outer surface of the film and wherein the coated portion of the film exhibits an Elmendorf tear in at least one of the machine direction or cross direction that is at least 20% less than the Elmendorf tear of the uncoated portion in the same direction, with the Elmendorf tear being measured in accordance with ASTM D1922.

The present invention provides coated films and packages formed from such films. In one aspect, a partially coated film comprises (a) a film having two outer surfaces, wherein a first outer surface is provided by a film layer that comprises from 70 to 100 percent by weight of a polyolefin having a density of 0.860 to 0.965 g/cm.sup.3; and (b) a coating on the first outer surface of the film comprising polyurethane, wherein the coating covers less than 25% of the surface area of the first outer surface of the film and wherein the coated portion of the film exhibits an Elmendorf tear in at least one of the machine direction or cross direction that is at least 20% less than the Elmendorf tear of the uncoated portion in the same direction, with the Elmendorf tear being measured in accordance with ASTM D1922.

An erosion resistant article such as rotor blades for helicopters and wind turbines having the leading edge surface protected from damage from high speed impingement of rain or sand with a protective coating formed from specific polyurethane or polyurea coating having a defined set of minimum physical properties where the protective coating can be applied as a liquid coating and cured in place or as a preformed complementary shaped covering to protect the leading edge against erosion damage in service.

An erosion resistant article such as rotor blades for helicopters and wind turbines having the leading edge surface protected from damage from high speed impingement of rain or sand with a protective coating formed from specific polyurethane or polyurea coating having a defined set of minimum physical properties where the protective coating can be applied as a liquid coating and cured in place or as a preformed complementary shaped covering to protect the leading edge against erosion damage in service.