Abstract: Object: To provide thermally expandable microspheres having little sag. Resolution Means: The thermally expandable microspheres have a structure in which a foaming agent is encapsulated in an outer shell formed from a polymer, wherein, the ratio (%) of (R2/R1)×100 is at least 105%, where R1 is the expansion ratio after the thermally expandable microspheres have been heat-treated for 5 minutes at 150° C. and then foamed by heating for 2 minutes at 200° C., and R2 is the expansion ratio after the thermally expandable microspheres have been heat-treated for 5 minutes at 150° C. and then foamed by heating for 4 minutes at 200° C.

Abstract: This invention aims to provide a thermally foamable microsphere which is excellent in heat resistance, has a high expansion ratio, and shows stable foaming behavior; a method of producing the thermally foamable microsphere; and suitable use thereof. This invention provides a thermally foamable microsphere in which an outer shell encapsulating a foaming agent is formed of a copolymer having a polymethacrylimide structure. In particular, this invention provides a thermally foamable microsphere in which monomers capable of forming the polymethacrylimide structure by a copolymerization reaction are methacrylonitrile and methacrylic acid. Moreover, this invention provides a method of producing the thermally foamable microsphere and use of the thermally foamable microsphere as an additive.

Abstract: Object: To provide thermally expandable microspheres having little sag. Resolution Means: The thermally expandable microspheres have a structure in which a foaming agent is encapsulated in an outer shell formed from a polymer, wherein, the ratio (%) of (R2/R1)×100 is at least 105%, where R1 is the expansion ratio after the thermally expandable microspheres have been heat-treated for 5 minutes at 150° C. and then foamed by heating for 2 minutes at 200° C., and R2 is the expansion ratio after the thermally expandable microspheres have been heat-treated for 5 minutes at 150° C. and then foamed by heating for 4 minutes at 200° C.

Abstract: Object: To provide heat-expandable microspheres with which large-diameter foamed particles which are lightweight and have enhanced strength, cushioning properties, and the like can be formed. Resolution Means: Heat-expandable microspheres having a foaming agent encapsulated in an outer shell of a polymer, the heat-expandable microspheres having an average particle size (D50) before foaming of from 100 to 500 ?m, and a coefficient of variation of a particle size distribution before foaming (logarithmic scale) of not greater than 15%.

Abstract: Provided are heat-expandable microspheres in which the water content can be adjusted easily and quickly by efficiently dehydrating the water present in the heat-expandable microspheres. Resolution Means Heat-expandable microspheres having a structure in which a foaming agent is encapsulated inside an outer shell formed from a polymer, the average value of the degrees of circularity, calculated based on a parameter indicating a particle diameter of each particle of the heat-expandable microspheres and a parameter indicating the circumference, being 0.985 or less are provided.

Abstract: This invention aims to provide a thermally foamable microsphere which is excellent in heat resistance, has a high expansion ratio, and shows stable foaming behavior; a method of producing the thermally foamable microsphere; and suitable use thereof. This invention provides a thermally foamable microsphere in which an outer shell encapsulating a foaming agent is formed of a copolymer having a polymethacrylimide structure. In particular, this invention provides a thermally foamable microsphere in which monomers capable of forming the polymethacrylimide structure by a copolymerization reaction are methacrylonitrile and methacrylic acid. Moreover, this invention provides a method of producing the thermally foamable microsphere and use of the thermally foamable microsphere as an additive.

Abstract: This invention aims to provide a thermally foamable microsphere which is excellent in heat resistance, has a high expansion ratio, and shows stable foaming behavior; a method of producing the thermally foamable microsphere; and suitable use thereof. This invention provides a thermally foamable microsphere in which an outer shell encapsulating a foaming agent is formed of a copolymer having a polymethacrylimide structure. In particular, this invention provides a thermally foamable microsphere in which monomers capable of forming the polymethacrylimide structure by a copolymerization reaction are methacrylonitrile and methacrylic acid. Moreover, this invention provides a method of producing the thermally foamable microsphere and use of the thermally foamable microsphere as an additive.

Abstract: This invention aims to provide a thermally foamable microsphere which is excellent in heat resistance, has a high expansion ratio, and shows stable foaming behavior; a method of producing the thermally foamable microsphere; and suitable use thereof. This invention provides a thermally foamable microsphere in which an outer shell encapsulating a foaming agent is formed of a copolymer having a polymethacrylimide structure. In particular, this invention provides a thermally foamable microsphere in which monomers capable of forming the polymethacrylimide structure by a copolymerization reaction are methacrylonitrile and methacrylic acid. Moreover, this invention provides a method of producing the thermally foamable microsphere and use of the thermally foamable microsphere as an additive.

Abstract: This invention aims to provide a thermally foamable microsphere which is excellent in heat resistance, has a high expansion ratio, and shows stable foaming behavior; a method of producing the thermally foamable microsphere; and suitable use thereof. This invention provides a thermally foamable microsphere in which an outer shell encapsulating a foaming agent is formed of a copolymer having a polymethacrylimide structure. In particular, this invention provides a thermally foamable microsphere in which monomers capable of forming the polymethacrylimide structure by a copolymerization reaction are methacrylonitrile and methacrylic acid. Moreover, this invention provides a method of producing the thermally foamable microsphere and use of the thermally foamable microsphere as an additive.

Abstract: A thermally foamable microsphere having a structure that a foaming agent is encapsulated in an outer shell formed from a polymer, wherein the foaming agent contains isododecane, and a production process of the thermally foamable microsphere by a suspension polymerization process using a polymerizable monomer and a foaming agent containing dodecane.

Abstract: This invention aims to provide a thermally foamable microsphere which is excellent in heat resistance, has a high expansion ratio, and shows stable foaming behavior; a method of producing the thermally foamable microsphere; and suitable use thereof. This invention provides a thermally foamable microsphere in which an outer shell encapsulating a foaming agent is formed of a copolymer having a polymethacrylimide structure. In particular, this invention provides a thermally foamable microsphere in which monomers capable of forming the polymethacrylimide structure by a copolymerization reaction are methacrylonitrile and methacrylic acid. Moreover, this invention provides a method of producing the thermally foamable microsphere and use of the thermally foamable microsphere as an additive.

Abstract: A thermally foamable microsphere having a structure that a foaming agent is encapsulated in an outer shell formed from a polymer, wherein supposing an electric conductivity of a water extract obtained by Step 1 of dispersing 5 g of the thermally foamable microsphere in 20 g of ion-exchanged water having a pH of 7 and an electric conductivity of ?1 at a temperature of 25° C. to prepare a liquid dispersion; and Step 2 of shaking the liquid dispersion at the same temperature for 30 minutes to conduct a water extraction treatment, as measured at 25° C. is ?2, a difference ?2??1 between ?2 and ?1 is at most 1 mS/cm, and a production process including measuring an electric conductivity of a filtrate in the washing step to obtain a thermally foamable microsphere exhibiting a desired electric conductivity on the basis of a previously prepared relational expression between the electric conductivity of the filtrate and the electric conductivity of a water extract of the thermally foamable microsphere.

Abstract: A thermally foamable microsphere having a structure that a foaming agent is encapsulated in an outer shell formed from a polymer, wherein the foaming agent contains isododecane, and a production process of the thermally foamable microsphere by a suspension polymerization process using a polymerizable monomer and a foaming agent containing dodecane.

Abstract: A method of refining a crystal of a crude cyclic ester comprises the steps of supplying the crude cyclic ester to a vertically extending cylindrical refiner (1) from an inlet (3) provided at a lower part of the refiner (1), agitating the crude cyclic ester by an agitator provided in the refiner (1) to make the crude cyclic ester flow upwardly, refining the crystals of the crude cyclic ester by counterflow-contact between the upflowing crude cyclic ester and a downflowing melted liquid containing a refined crystal component, and taking out refined crystals of the crude cyclic ester from an outlet (4) provided at an upper part of the refiner (1).

Abstract: Foamable microspheres with a foaming agent enclosed in the shell of a polymer, wherein the average particle diameter of the microspheres is within a range of 3 to 100 &mgr;m, and the coefficient of variation of the particle diameter distribution thereof is at most 1.50%, and production process of foamable microspheres by a suspension polymerization process.

Abstract: A method of refining a crystal of a crude cyclic ester comprises the steps of supplying the crude cyclic ester to a vertically extending cylindrical refiner (1) from an inlet (3) provided at a lower part of the refiner (1), agitating the crude cyclic ester by an agitator provided in the refiner (1) to make the crude cyclic ester flow upwardly, refining the crystals of the crude cyclic ester by counterflow-contact between the upflowing crude cyclic ester and a downflowing melted liquid containing a refined crystal component, and taking out refined crystals of the crude cyclic ester from an outlet (4) provided at an upper part of the refiner (1).