公开(公告)号：JPH05330812A

公开(公告)日：1993-12-14

申请号：JP16042092

申请日：1992-05-27

Applicant: KAWASAKI STEEL CO ,  BRIDGESTONE CORP

Inventor： NAGAYAMA KATSUHIRO ,  TORII TAKAYUKI ,  HARAOKA TAKUJI ,  HATANO HITOMI ,  FUKUDA NORIYOSHI ,  SAITO TASUKU ,  ISHINO YUICHI ,  MARUYAMA TAKAYUKI

IPC: C01B31/02 ,  C10N20/06 ,  C10N30/02 ,  C10N40/14 ,  C10N70/00

Abstract: PURPOSE:To attain small initial viscosity by pulverizing a carbonaceous powder raw material by a jet pulverizer to enhance the sphericity of particles to apply the obtained carbonaceous particulate to electroviscous fluid. CONSTITUTION:The carbonaceous powder material (e.g. coal or petroleum tar, pitch and resin or the like) is heat-treated and pulverized to 0.5-40mum average particle diameter. In this case, the sphericity of the particle is heightened by using a particle collision type jet pulverizer, and the obtained carbonaceous particulate is used as a dielectric particle and is dispersed into an oily medium excellent in electrical insulation resistance to obtain the electroviscous fluid. At the time of applying voltage to the electroviscous fluid, the apparent viscosity of the fluid is rapidly and reversibly changed.

公开(公告)号：JPH05193919A

公开(公告)日：1993-08-03

申请号：JP968692

申请日：1992-01-23

Applicant: KAWASAKI STEEL CO ,  BRIDGESTONE CORP

Inventor： HARAOKA TAKUJI ,  TORII TAKAYUKI ,  NAGAYAMA KATSUHIRO ,  HATANO HITOMI ,  FUKUDA NORIYOSHI ,  ISHINO YUICHI ,  MARUYAMA TAKAYUKI ,  SAITO TASUKU

IPC: C01B31/02 ,  C10M125/02 ,  C10N20/06 ,  C10N40/14 ,  C10N60/04 ,  C10N70/00

Abstract: PURPOSE:To produce a fine particle excellent in electroviscous effect by wet- oxidizing a carbonaceous powder. CONSTITUTION:Coal, coal tar, coal tar pitch, etc., are heat-treated to obtain a carbonaceous powder, and the powder is wet-oxidized. Hydrogen peroxide, nitric acid-sulfuric acid mixtures, etc., are used as the oxidizing agent. The ratio of the number of carbon atoms to the number of hydrogen atoms in the powder is preferably controlled to 1.70 to 3.50. Consequently, a dielectric fine particle capable of exhibiting an excellent electroviscous effect in an electroviscous fluid is obtained.

公开(公告)号：JPH03279206A

公开(公告)日：1991-12-10

申请号：JP17543290

申请日：1990-07-04

Applicant: BRIDGESTONE CORP

Inventor： FUKUDA NORIYOSHI ,  NAGAYAMA KATSUHIRO ,  TORII TAKAYUKI ,  HATANO HITOMI ,  ISHINO YUICHI ,  MARUYAMA TAKAYUKI ,  SAITO TASUKU

IPC: C10M125/02 ,  C01B31/02 ,  C10M171/00 ,  C10N20/06 ,  C10N40/14 ,  C10N70/00

Abstract: PURPOSE:To obtain the subject powder excellent in stability for a long period and stability to temperature by specifying the value of C/H ratio within a specified range and/or the amount of weight loss within a specific temperature range in nitrogen atmosphere within a specified range. CONSTITUTION:Carbonaceous powder used as dielectric fine particles in an electroviscous fluid obtained by dispersing the dielectric fine particles in an oily medium excellent in electrical insulating properties. The aforementioned powder is provided so as to satisfy at least one condition of the following. The value of the ratio (C/H) between the numbers of carbon atoms to hydrogen atoms within the range of 1.70-3.50 and the amount of weight loss at a temperature within the range of 400-600 deg.C in nitrogen atmosphere within the range of 0.5-13.0wt.%. Thereby, the objective carbon powder excellent in stability for a long period and stability to temperature for an electroviscous fluid is obtained.

公开(公告)号：JPH06330078A

公开(公告)日：1994-11-29

申请号：JP11827993

申请日：1993-05-20

Applicant: KAWASAKI STEEL CO ,  BRIDGESTONE CORP

Inventor： TAKAGI KO ,  HARAOKA TAKUJI ,  HATANO HITOMI ,  FUKUDA NORIYOSHI ,  MARUYAMA TAKAYUKI ,  SAITO TASUKU ,  OGINO TAKAO

IPC: B01J13/00 ,  C10M169/04 ,  C10M171/00 ,  C10N20/06 ,  C10N30/02 ,  C10N40/14

Abstract: PURPOSE:To stably obtain are electroviscous fluid responding to various prescribed properties such as a small current value and a great change in viscosity in applying a voltage thereto by mixing plural kinds of electroviscous fluids with dielectric particles different in electrical characteristics. CONSTITUTION:A electroviscous fluid is prepared by dispersing plural kinds of dielectric particles dispersed in an oily medium (e.g. transformer oil) excellent in electrical insulating properties. In the process, electroviscous fluids and/or dielectric particles having the maximum value (f0.max) and the minimum value (f0.min) in relaxation frequencies (f0) of an electroviscous fluid prepared by using one kind each of the plural dielectric particles alone satisfying the relationship of the formula are mixed. Specifically, the electroviscous fluid is prepared according to, e.g. a method for mutually mixing the plural kinds of electroviscous fluids or mixing the plural kinds of dielectric particles and then dispersing the mixed dielectric particles in the oily medium. Furthermore, the oily medium in the plural kinds of electroviscous fluids is preferably the same. Carbonaceous powder consisting essentially of carbon is preferred as the dielectric particles.

公开(公告)号：JPH06299181A

公开(公告)日：1994-10-25

申请号：JP4971993

申请日：1993-03-11

Applicant: KAWASAKI STEEL CO ,  BRIDGESTONE CORP

Inventor： HARAOKA TAKUJI ,  TORII TAKAYUKI ,  NAGAYAMA KATSUHIRO ,  HATANO HITOMI ,  TAKAGI KO ,  FUKUDA NORIYOSHI ,  ISHINO YUICHI ,  MARUYAMA TAKAYUKI ,  SAITO TASUKU ,  OGINO TAKAO

IPC: C01B31/02 ,  C09C1/48 ,  C09C1/56 ,  C10M125/02 ,  C10N20/06 ,  C10N30/00 ,  C10N40/14 ,  C10N70/00

Abstract: PURPOSE:To stably obtain high-quality carbonaceous powder for an electroviscous fluid without any rise in current value in applying a voltage by heat-treating tar, pitch, a resin, etc., regulating a value of carbonization ratio, then suppressing an increase in oxygen content of the resultant product to a specific value or below, pulverizing the prepared product and classifying the powder. CONSTITUTION:An organic compound such as coal-based tar, coal-based pitch, petroleum-based tar, petroleum-based pitch, a resin and a polymer of a condensed aromatic compound is heat-treated to regulate a value of carbonization ratio (C/H) which is the ratio of the number of carbon atoms to that of hydrogen atoms within the range of 2.00 to 3.50. The resultant substance obtained by the heat treatment is then pulverized and classified by suppressing an increase in oxygen content to

公开(公告)号：JPH06263417A

公开(公告)日：1994-09-20

申请号：JP4962293

申请日：1993-03-10

Applicant: KAWASAKI STEEL CO ,  BRIDGESTONE CORP

Inventor： HATANO HITOMI ,  HARAOKA TAKUJI ,  TAKAGI KO ,  FUKUDA NORIYOSHI ,  OGINO TAKAO ,  MARUYAMA TAKAYUKI ,  SAITO TASUKU

IPC: C01B31/02 ,  C10M169/04 ,  C10N20/00 ,  C10N20/06 ,  C10N40/14

Abstract: PURPOSE:To provide a carbonaceous powder for electroviscous fluid low in current value, a production method and an electroviscous fluid. CONSTITUTION:In the carbonaceous powder for electroviscous fluid >=1.70 to =0.5% to =400 deg.C to

公开(公告)号：JPH0718283A

公开(公告)日：1995-01-20

申请号：JP16229193

申请日：1993-06-30

Applicant: KAWASAKI STEEL CO ,  BRIDGESTONE CORP

Inventor： HATANO HITOMI ,  HARAOKA TAKUJI ,  FUKUDA NORIYOSHI ,  TAKAGI KO ,  MARUYAMA TAKAYUKI ,  SAITO TASUKU ,  OGINO TAKAO

IPC: B01J13/00 ,  C01B31/02 ,  C10M125/02 ,  C10N20/00 ,  C10N20/06 ,  C10N40/04 ,  C10N40/08 ,  C10N40/14 ,  C10N70/00

Abstract: PURPOSE:To provide an electroviscous fluid which has excellent electroviscous characteristics such as an excellent response due to the much more stable viscosity or electric current under applied voltage than the conventional ones and a low electric current under applied voltage. CONSTITUTION:An electroviscous fluid is obtd. by using, as fine dielectric particles, a carbonaceous powder which provides an extract having an extinction of 2.5 or lower at a certain wavelength in the range of 400-500nm when the powder is extracted with the same wt. of toluene at its b.p. for 10min or longer.

公开(公告)号：JPH06234985A

公开(公告)日：1994-08-23

申请号：JP2115993

申请日：1993-02-09

Applicant: KAWASAKI STEEL CO ,  BRIDGESTONE CORP

Inventor： HARAOKA TAKUJI ,  HATANO HITOMI ,  FUKUDA NORIYOSHI ,  SAITO TASUKU ,  OGINO TAKAO ,  MARUYAMA TAKAYUKI

IPC: B01J13/00 ,  C01B31/02 ,  C10M103/02 ,  C10N40/14 ,  C10N70/00

Abstract: PURPOSE:To obtain an electroviscous fluid which, upon application of a given voltage, undergoes a viscosity change at a lower value of electric current flowing through the fluid and which has a low initial viscosity. CONSTITUTION:The electroviscous fluid is a dispersion of either a particulate carbonaceous substance produced through melting at 300-500 deg.C or a particulate carbonaceous substance produced from a material scarcely containing any nitrogen, oxygen, and sulfur.

公开(公告)号：JPH06234512A

公开(公告)日：1994-08-23

申请号：JP2019893

申请日：1993-02-08

Applicant: KAWASAKI STEEL CO ,  BRIDGESTONE CORP

Inventor： HARAOKA TAKUJI ,  TAKAGI KO ,  HATANO HITOMI ,  FUKUDA NORIYOSHI ,  MARUYAMA TAKAYUKI ,  OGINO TAKAO ,  SAITO TASUKU

IPC: C01B31/02 ,  C10M125/02

Abstract: PURPOSE:To produce an electroviscous fluid reduced in the viscosity at the time of applying no voltage (initial viscosity). CONSTITUTION:In the electroviscous fluid obtained by dispersing a dielectric particulate in an oily medium excellent in electric insulation, the specific surface area of the particle used as a dispersoid is controlled to /g. The particle has preferably 0.5-40mum particle diameter, =20mum particle diameter and

公开(公告)号：JPH03247696A

公开(公告)日：1991-11-05

申请号：JP4241090

申请日：1990-02-26

Applicant: BRIDGESTONE CORP

Inventor： ISHINO YUICHI ,  MARUYAMA TAKAYUKI ,  SAITO TASUKU ,  FUKUDA NORIYOSHI ,  NAGAYAMA KATSUHIRO ,  TORII TAKAYUKI

IPC: C01B31/00 ,  B01J13/00 ,  C10M125/02 ,  C10M125/26 ,  C10N20/06 ,  C10N40/14 ,  H01B3/20

Abstract: PURPOSE:To provide the subject powder having long-term stability and temperature stability by dispersing dielectric material fine particles comprising carbonaceous powder in an electrically insulating oily medium, the carbonaceous powder being prepared by allowing carbon to grow on inorganic fine particles as generation nuclei. CONSTITUTION:Dielectric material fine particles comprising carbonaceous powder preferably having a particle diameter of 0.5-5mu and prepared by allowing carbon to grow on generation nuclei comprising the inorganic fine particles of silica, alumina, rutile, aluminum silicate, etc., having an average particle diameter of preferably 0.01-1mu are dispersed in an oily medium such as a spindle oil, a transformer oil, a chlorinated paraffin, a silicone, oil, etc., having a high electrically insulating property to provide the objective carbonaceous powder.