Somar Corporation

Hideo Ochi

Masaaki Toyoda

Akihide Igari

Akira Yasuda

Zenbee Nakagawa

Jun Takahashi

Tomoyuki Kitaori

A laser beam absorbing resin composition is disclosed which includes 100 parts by weight of a resin, and 1-100 parts by weight of composite particles having an average particle diameter of 0.1-50 .mu.m and each including a particulate, laser beam absorbing inorganic substance, and a colorant physically bonded directly to the inorganic substance and capable of discoloring upon being heated at a temperature of 250.degree. C. or more, the weight ratio of the colorant to the inorganic substance being in the range of 1:99 to 50:50. By irradiating a shaped, hardened body of the above composition with a laser beam, the colorant is thermally decomposed, so that the color of the irradiated surface is changed and becomes discriminative from that of non-irradiated surface.

Laser beam absorbing resin composition, coloring material therefor and

A laser beam absorbing resin composition is disclosed which includes 100 parts by weight of a thermosetting resin, a colorant capable of discoloring upon being heated at a temperature of 250.degree. C. or more, and at least 10 parts by weight of a particulate, laser beam absorbing substance which has an average particle size of 50 .mu.m or less and which is at least one member selected from cordierite and zeolite. By irradiating a shaped, hardened body of the above composition with a laser beam, the colorant is thermally decomposed, so that the color of the irradiated surface is changed and becomes discriminitive from that of non-irradiated surface.

Laser beam absorbing resin composition and laser beam marking method

A varistor material having a non-linear coefficient of at least 30 and a varistor voltage of at least 800 V/mm is disclosed. The varistor is produced by a method including commingling an admixture of ZnO and a manganese compound while preventing the admixture from contacting with a surface containing an element belonging to group IIIb of the Periodic Table. The resulting mixture is calcined and then pulverized while preventing the contact with a IIIb element-containing surface to obtain a pulverized product having a content of impurity compounds of a IIIb element of not greater than 20 ppm by weight. The pulverized product is molded and sintered at such a temperature as to obtain the varistor formed from particles with an average particle size of not greater than 5 .mu.m.

Sintered varistor material with small particle size

A varistor having a non-linear coefficient of at least 40 and improved stability for DC stress is produced by a method including a step of mixing ZnO powder with a solvent solution of Mn and Pb compounds, a step of calcining the resultig mixture, and a step of pulverizing the calcined product to obtain a pulverized product. These steps are performed while preventing the contamination with a Group IIIb or Ia element, so that the pulverized product has MnO and PbO contents of 3-7 mole % and 0.003-0.01 mole %, respectively, and a content of impurity compounds of a IIIb or Ia element of not greater than 20 ppm by weight. The pulverized product is molded and sintered to obtain the varistor.

Method of producing varistor

A varistor material is disclosed which has a composition consisting essentially of 93-97 mole % of ZnO and 3-7 mole % of MnO, a non-linear coefficient .alpha. of at least 20 and such a bulk density as to provide a porosity of greater than 15% but not greater than 50%, wherein the porosity is defined as follows:

Varistor material and method of producing same from zinc oxide and

A process for the production of a varistor material having a nonlinear index (.alpha.) of at least 20, which comprises adding a manganese compound to zinc oxide; heating the obtained mixture in the form of a powder in the atomosphere at 1050.degree. to 1150.degree. C.; grinding the material to give a particle size of 150 mesh or below; molding the powder into a desired shape; and sintering the same at 1200.degree. to 1350.degree. C.; is disclosed.

Process for production of varistor material

A novel copolymer containing a plurality of first and second monomer units having the following general formulas (I) and (II), respectively: ##STR1## wherein R.sub.1 stands for hydrogen or methyl and Ar stands for an aryl, ##STR2## wherein R.sub.2 stands for hydrogen or methyl and X stands for -CH.sub.2 CH.sub.2 -, -CH.sub.2 CH(OH)CH.sub.2 - or -CH.sub.2 CH(CH.sub.2 OH)- and Y stands for o- or p-chlorophenyl, the molar ratio of the first monomer unit to the second monomer unit being 94:6 to 98:2. The copolymer becomes insoluble to a developing liquid when exposed to high energy radiations and is used for forming resist pattern on a silicon wafer or the like substrate.

Growing community of inventors

Misato, Japan

Hideo Ochi