Abstract: The present invention relates to a heat retaining agent for agricultural films comprising hydrotalcite-type particles which can satisfy all of a transparency required for heat retaining agents for agricultural films, dispersibility in resins, and handling property at a high level. According to the present invention, there are provided hydrotalcite-type particles having an oil absorption of not more than 35 mL/100 g and a ratio of an oil absorption to a plate surface diameter (oil absorption/plate surface diameter) of 140 to 190; a heat retaining agent for agricultural films comprising the hydrotalcite-type particles; and an agricultural film comprising the heat retaining agent for agricultural films.

Abstract: The present invention relates to a heat retaining agent for agricultural films comprising hydrotalcite-type particles which can satisfy all of a transparency required for heat retaining agents for agricultural films, dispersibility in resins, and handling property at a high level. According to the present invention, there are provided hydrotalcite-type particles having an oil absorption of not more than 35 mL/100 g and a ratio of an oil absorption to a plate surface diameter (oil absorption/plate surface diameter) of 140 to 190; a heat retaining agent for agricultural films comprising the hydrotalcite-type particles; and an agricultural film comprising the heat retaining agent for agricultural films.

Abstract: According to the present invention, there are provided hydrotalcite-based compound particles surface-treated with an organic compound having not less than 3 carbon atoms, have a specific surface area of 5 to 150 m2/g, wherein a conceptual value x corresponding to micropores and ultramicropores, and a conceptual value y corresponding to volumes of macropores and micropores, both calculated from a water vapor adsorption curve thereof when exposed to a temperature of 25° C. and a humidity of 50% for 250 hours, are respectively within specific ranges. The hydrotalcite-based compound particles of the present invention are capable of capturing even a very small amount of halogens contained in various resins, and exhibiting an excellent effect of preventing deterioration of the resins.

Abstract: Preparing Mg—Zn—Al-based hydrotalcite-type particles which comprise core particles composed of Mg—Al-based hydrotalcite and an Mg—Zn—Al-based hydrotalcite layer formed on the surface of the core particle, and have an average plate surface diameter of 0.1 to 1.0 .mu.m and a refractive index adjustable to a required value in the range of 1.48 to 1.56.

Abstract: In accordance with the present invention, the surface of hydrotalcite-based compound particles can be prevented from being attacked by chlorine ions desorbed from resins. The silicic acid-coated hydrotalcite-based compound particles obtained by coating the surface of Mg—Al-based or Mg—Zn—Al-based hydrotalcite-based compound particles with silicic acid in an amount of 0.25 to 25% by weight in terms of SiO2 based on the weight of the hydrotalcite-based compound particles, and drying the thus coated hydrotalcite-based compound particles at a temperature of 105 to 150° C. as well as the hydrotalcite-based compound particles obtained by heat-treating the silicic acid-coated hydrotalcite-based compound particles at a temperature of 150 to 350° C. are used as a stabilizer for chlorine-containing resin compositions.

Abstract: A chlorine-containing resin composition for covering an electric wire of the present invention, has a heat stability of not less than 240 minutes and a volume resistivity of 5.0×1013 to 1.0×1016 ?·cm when measured according to JIS K6723, and comprises: 100 parts by weight of a chlorine-containing resin, and 1.5 to 10 parts by weight of Mg—Al-based hydrotalcite-type particles having a composition represented by the formula: [MgxCay].Alz.(OH)2.An?p.mH2O ?wherein 0.2?z/(x+z)?0.6; 0.01?y/(x+z)?0.20; x+y+z=1; p=(2(x+y?1)+3z)/n; A is a n-valent anion; and m is more than 0 and not more than 0.75, having a plate surface diameter of 0.1 to 1.0 ?m and a thickness of 0.02 to 0.08 ?m, and containing calcium at a molar ratio of Ca to a sum of Mg and Al of 0.01:1 to 0.20:1, and having a heat-resisting time of not less than 4 hours upon a chlorine-containing resin composition containing the Mg—Al-based hydrotalcite-type particles.

Abstract: A chlorine-containing resin composition for covering an electric wire of the present invention, has a heat stability of not less than 240 minutes and a volume resistivity of 5.0?1013 to 1.0×1016 ?·cm when measured according to JIS K6723, and comprises: 100 parts by weight of a chlorine-containing resin, and 1.5 to 10 parts by weight of Mg—Al-based hydrotalcite-type particles having a composition represented by the formula: [MgxCay]·Alz·(OH)2·An?p·mH2O wherein 0.2?z/(x+z)?0.6; 0.01?y/(x+z)?0.20; x+y+z=1; p=(2(x+y?1)+3z)/n; A is a n-valent anion; and m is more than 0 and not more than 0.75, having a plate surface diameter of 0.1 to 1.0 ?m and a thickness of 0.02 to 0.08 ?m, and containing calcium at a molar ratio of Ca to a sum of Mg and Al of 0.01:1 to 0.20:1, and having a heat-resisting time of not less than 4 hours upon a chlorine-containing resin composition containing the Mg—Al-based hydrotalcite-type particles.

Abstract: Mg-Zn-Al-based hydrotalcite-type particles comprise core particles composed of Mg-Al-based hydrotalcite and an Mg-Zn-Al-based hydrotalcite layer formed on the surface of the core particle, and have an average plate surface diameter of 0.1 to 1.0 ?m and a refractive index being adjustable to a required value in the range of 1.48 to 1.56; and a resin composition contains the Mg-Zn-Al-based hydrotalcite-type particles. The Mg-Zn-Al-based hydrotalcite-type particles can exhibit a large plate surface diameter and an appropriate thickness whose refractive index is adjustable to various values, and the resin composition can show not only higher resin stability and functional properties, but also an excellent transparency as compared to those using conventional hydrotalcite-type particles.

Abstract: According to the present invention, there are provided hydrotalcite-based compound particles surface-treated with an organic compound having not less than 3 carbon atoms, have a specific surface area of 5 to 150 m2/g, wherein a conceptual value x corresponding to micropores and ultramicropores, and a conceptual value y corresponding to volumes of macropores and micropores, both calculated from a water vapor adsorption curve thereof when exposed to a temperature of 25° C. and a humidity of 50% for 250 hours, are respectively within specific ranges. The hydrotalcite-based compound particles of the present invention are capable of capturing even a very small amount of halogens contained in various resins, and exhibiting an excellent effect of preventing deterioration of the resins.

Abstract: A chlorine-containing resin composition for covering an electric wire of the present invention, has a heat stability of not less than 240 minutes and a volume resistivity of 5.0×1013 to 1.0×1016 ?·cm when measured according to JIS K6723, and comprises: 100 parts by weight of a chlorine-containing resin, and 1.5 to 10 parts by weight of Mg—Al-based hydrotalcite-type particles having a composition represented by the formula: [MgxCay]•Alz•(OH)2•An?p•mH2O wherein 0.2?z/(x+z)?0.6; 0.01?y/(x+z)?0.20; x+y+z=1; p=(2(x+y?1)+3z)/n; A is a n-valent anion; and m is more than 0 and not more than 0.75, having a plate surface diameter of 0.1 to 1.0 ?m and a thickness of 0.02 to 0.08 ?m, and containing calcium at a molar ratio of Ca to a sum of Mg and Al of 0.01:1 to 0.20:1, and having a heat-resisting time of not less than 4 hours upon a chlorine-containing resin composition containing the Mg—Al-based hydrotalcite-type particles.

Abstract: A chlorine-containing resin composition for covering an electric wire of the present invention, has a heat stability of not less than 240 minutes and a volume resistivity of 5.0×1013 to 1.0×1016 ?·cm when measured according to JIS K6723, and comprises: 100 parts by weight of a chlorine-containing resin, and 1.5 to 10 parts by weight of Mg—Al-based hydrotalcite-type particles having a composition represented by the formula: [MgxCay].Alz.(OH)2.An?p.mH2O wherein 0.2?z/(x+z)?0.6; 0.01?y/(x+z)?0.20; x+y+z=1; p=(2(x+y?1)+3z)/n; A is a n-valent anion; and m is more than 0 and not more than 0.75, having a plate surface diameter of 0.1 to 1.0 ?m and a thickness of 0.02 to 0.08 ?m, and containing calcium at a molar ratio of Ca to a sum of Mg and Al of 0.01:1 to 0.20:1, and having a heat-resisting time of not less than 4 hours upon a chlorine-containing resin composition containing the Mg—Al-based hydrotalcite-type particles.

Abstract: A chlorine-containing resin composition for covering an electric wire of the present invention, has a heat stability of not less than 240 minutes and a volume resistivity of 5.0×1013 to 1.0×1016 ?·cm when measured according to JIS K6723, and comprises: 100 parts by weight of a chlorine-containing resin, and 1.5 to 10 parts by weight of Mg—Al-based hydrotalcite-type particles having a composition represented by the formula: [MgxCay]·Alz·(OH)2·An?p·mH2O wherein 0.2?z/(x+z)?0.6; 0.01?y/(x+z)?0.20; x+y+z=1; p=(2(x+y?1)+3z)/n; A is a n-valent anion; and m is more than 0 and not more than 0.75, having a plate surface diameter of 0.1 to 1.0 ?m and a thickness of 0.02 to 0.08 ?m, and containing calcium at a molar ratio of Ca to a sum of Mg and Al of 0.01:1 to 0.20:1, and having a heat-resisting time of not less than 4 hours upon a chlorine-containing resin composition containing the Mg—Al-based hydrotalcite-type particles.

Abstract: A chlorine-containing resin composition for covering an electric wire of the present invention, has a heat stability of not less than 240 minutes and a volume resistivity of 5.0×1013 to 1.0×1016 ?·cm when measured according to JIS K6723, and comprises: 100 parts by weight of a chlorine-containing resin, and 1.5 to 10 parts by weight of Mg—Al-based hydrotalcite-type particles having a composition represented by the formula: [MgxCay].Alz.(OH)2.An?p.mH2O wherein 0.2?z/(x+z)?0.6; 0.01?y/(x+z)?0.20; x+y+z=1; p=(2(x+y?1)+3z)/n; A is a n-valent anion; and m is more than 0 and not more than 0.75, having a plate surface diameter of 0.1 to 1.0 ?m and a thickness of 0.02 to 0.08 ?m, and containing calcium at a molar ratio of Ca to a sum of Mg and Al of 0.01:1 to 0.20:1, and having a heat-resisting time of not less than 4 hours upon a chlorine-containing resin composition containing the Mg—Al-based hydrotalcite-type particles.

Abstract: Mg—Zn—Al-based hydrotalcite-type particles comprise core particles composed of Mg—Al-based hydrotalcite and an Mg—Zn—Al-based hydrotalcite layer formed on the surface of the core particle, and have an average plate surface diameter of 0.1 to 1.0 &mgr;m and a refractive index being adjustable to a required value in the range of 1.48 to 1.56; and a resin composition contains the Mg—Zn—Al-based hydrotalcite-type particles. The Mg—Zn—Al-based hydrotalcite-type particles can exhibit a large plate surface diameter and an appropriate thickness whose refractive index is adjustable to various values, and the resin composition can show not only higher resin stability and functional properties, but also an excellent transparency as compared to those using conventional hydrotalcite-type particles.

Abstract: A chlorine-containing resin composition for covering an electric wire of the present invention, has a heat stability of not less than 240 minutes and a volume resistivity of 5.0×1013 to 1.

Abstract: A chlorine-containing resin composition for covering an electric wire of the present invention, has a heat stability of not less than 240 minutes and a volume resistivity of 5.0×1013 to 1.0×1016 &OHgr;·cm when measured according to JIS K6723, and comprises: 100 parts by weight of a chlorine-containing resin, and 1.5 to 10 parts by weight of Mg—Al-based hydrotalcite-type particles having a composition represented by the formula: [MgxCay]·Alz·(OH)2·An−p·mH2O  wherein 0.2≦z/(x+z)≦0.6; 0.01≦y/(x+z)≦0.20; x+y+z=1; p=(2(x+y−1)+3z)/n; A is a n-valent anion; and m is more than 0 and not more than 0.75, having a plate surface diameter of 0.1 to 1.0 &mgr;m and a thickness of 0.02 to 0.08 &mgr;m, and containing calcium at a molar ratio of Ca to a sum of Mg and Al of 0.01:1 to 0.

Abstract: The Mg—Al-based hydrotalcite-type particles according to the present invention have a plate surface diameter as large as from 0.1 to less than 1.0 &mgr;m, an adequate thickness ranging from 0.02 to 0.08 &mgr;m and a heat-resisting time of not less than 160 minutes when measured by a specific method, and are, therefore, suitable as a stabilizer for chlorine-containing resins.

Abstract: Disclosed herein are a process for producing poreless plate-like magnetite particles which have as large a plate ratio (average particle diameter/thickness) as possible and which are discrete each other, the process comprising the step of: obtained by oxidizing a suspension containing FeCO.sub.3 obtained by reacting an aqueous ferrous salt solution and an aqueous alkali carbonate solution by passing an oxygen-containing gas therethrough, wherein the suspension is obtained by reacting a ferrous salt solution containing 0.2 to 5.0 mol % of a ferric salt, calculated as Fe(III), based on Fe(II) and an aqueous alkali carbonate the amount of which is so controlled that the equivalent ratio of an alkali carbonate to the Fe(II) and Fe(III) in the aqueous ferrous salt solution is not less than 1 and the following general formula is satisfied: ##EQU1## and if necessary, 0.01 to 8.