Abstract: The present invention relates to a defoamer oil compound that contains an organopolysiloxane (A), a fine silica powder (B), and a group (C) that is represented by the organopolysiloxanes of formulas (I) and/or (II) (in the formulas, c, d, and e are each an integer of 0 or more, and at least one of X1 to X3 is the group represented by formula (i)). The component (C) is used as a surface treatment agent for the component (B). The present invention makes it possible to obtain a silicone-based defoamer composition that imparts good initial defoaming properties even in an alkaline foaming liquid, that exhibits very little loss in performance over time, and that has excellent defoaming performance.

Abstract: The present invention relates to a defoamer oil compound that contains an organopolysiloxane (A), a fine silica powder (B), and a group (C) that is represented by the organopolysiloxanes of formulas (I) and/or (II) (in the formulas, c, d, and e are each an integer of 0 or more, and at least one of X1 to X3 is the group represented by formula (i)). The component (C) is used as a surface treatment agent for the component (B). The present invention makes it possible to obtain a silicone-based defoamer composition that imparts good initial defoaming properties even in an alkaline foaming liquid, that exhibits very little loss in performance over time, and that has excellent defoaming performance.

Abstract: The present invention relates to a defoamer oil compound that contains an organopolysiloxane (A), a fine silica powder (B), and a group (C) that is represented by the organopolysiloxanes of formulas (I) and/or (II) (in the formulas, c, d, and e are each an integer of 0 or more, and at least one of X1 to X3 is the group represented by formula (i)). The component (C) is used as a surface treatment agent for the component (B). The present invention makes it possible to obtain a silicone-based defoamer composition that imparts good initial defoaming properties even in an alkaline foaming liquid, that exhibits very little loss in performance over time, and that has excellent defoaming performance.

Abstract: The present invention relates to a defoamer oil compound that contains an organopolysiloxane (A), a fine silica powder (B), and a group (C) that is represented by the organopolysiloxanes of formulas (I) and/or (II) (in the formulas, c, d, and e are each an integer of 0 or more, and at least one of X1 to X3 is the group represented by formula (i)). The component (C) is used as a surface treatment agent for the component (B). The present invention makes it possible to obtain a silicone-based defoamer composition that imparts good initial defoaming properties even in an alkaline foaming liquid, that exhibits very little loss in performance over time, and that has excellent defoaming performance.

Abstract: An oil compound used for defoaming includes (A) a substantially hydrophobic organopolysiloxane having a viscosity of 10 to 100,000 mm2/second at 25° C., and (B) finely divided silica that has undergone surface hydrophobization treatment, wherein when an insoluble matter is collected from the oil compound by using hexane and the spectra of the insoluble matter are measured by 29Si-CP/MAS-NMR, the peaks of the silica due to the SiO4/2 (Q) units on the silica surface are such that a ratio [(Q2+Q3)/Q4] between a total area (Q2+Q3) wherein Q2 is a peak area of a silicon atom having two unreacted silanol groups and Q3 is a peak area of a silicon atom having one unreacted silanol group and an area Q4 wherein Q4 is a peak area of a silicon atom having no unreacted silanol group is at 70/30 to 20/80.

Abstract: The present invention provides a method of producing silicon carbide, comprising: providing a silicon-crystal producing apparatus with a carbon heater; forming a silicon carbide by-product on a surface of the carbon heater when a silicon crystal is produced from a silicon melt contained in a container heated by the carbon heater under a non-oxidizing atmosphere; and collecting the silicon carbide by-product to produce the silicon carbide. A method that can produce silicon carbide with low energy at low cost is thereby provided.

Abstract: An oil compound used for defoaming includes (A) a substantially hydrophobic organopolysiloxane having a viscosity of 10 to 100,000 mm2/second at 25° C., and (B) finely divided silica that has undergone surface hydrophobization treatment, wherein when an insoluble matter is collected from the oil compound by using hexane and the spectra of the insoluble matter are measured by 29Si-CP/MAS-NMR, the peaks of the silica due to the SiO4/2 (Q) units on the silica surface are such that a ratio [(Q2+Q3)/Q4] between a total area (Q2+Q3) wherein Q2 is a peak area of a silicon atom having two unreacted silanol groups and Q3 is a peak area of a silicon atom having one unreacted silanol group and an area Q4 wherein Q4 is a peak area of a silicon atom having no unreacted silanol group is at 70/30 to 20/80.

Abstract: An organoxy-terminated organopolysiloxane of the general formula (A): wherein R is a monovalent hydrocarbon group, R1 is a monovalent hydrocarbon group of 1-18 carbon atoms, and R2 is an organic group of 1-18 carbon atoms, and “a” is an integer of 0, 1 or 2, is prepared by reacting an organopolysiloxane of the formula: HO(R2SiO)nH having a viscosity of 10-100,000 centistokes at 25° C. with an organoxysilane of the formula: (R2O)4-a—Si—(R1)a or a partial hydrolyzate thereof in the presence of a tetraalkoxytitanium.