摘要:
An aromatic polycarbonate of the present invention is produced by reacting an aromatic dihydroxy compound with a compound capable of introducing a carbonate bond, and has a viscosity-average molecular weight of 12,000 to 40,000 and a content of a cyclic oligomer represented by the formula (1) of not more than 1,000 ppm, in which the percentage of the content of said cyclic oligomer represented by the formula (1) based on the total contents of the cyclic oligomer represented by the formula (1), an oligomer represented by the formula (2) and an oligomer represented by the formula (3) satisfies the following relational formula [I]: 0
摘要:
An aromatic polycarbonate composition which has excellent thermal stability and maintains high transparency and a satisfactory hue even at high temperatures. The aromatic polycarbonate composition comprises: a polycarbonate obtained by reacting at least one aromatic dihydroxy compound with a compound capable of incorporating a carbonate bond; and a phosphorus compound represented by the following formula (1): wherein the eight R′s may be the same or different and each represents a hydrogen atom or an optionally substituted, aliphatic or aromatic, univalent group having 1 to 18 carbon atoms.
摘要:
A process for preparing a polycarbonate which comprises performing a transesterification and a polycondensation reaction with a diarylcarbonate and dihydroxyaryl compound, in a reaction apparatus composed of stainless steel comprising at least 12% by weight of Ni, and at least 22% by weight of Cr, and having Fe as the remaining main component. A polycarbonate which has a good color, is stable to hydrolysis and resistant to heat-yellowing is the resulting product.
摘要:
A process for producing an oxalate diester is provided. The oxalate diester is produced by reacting an aliphatic alcohol, carbon monoxide and molecular oxygen at an elevated temperature and under pressure in the presence of a catalyst comprising (1) metallic palladium or a palladium compound, (2) a heteropoly-acid and (3) at least one nitrogen compound selected from the group consisting of nitric acid, nitrogen oxides and esters of nitrous acid.
摘要:
A semiconductor memory device is of a bank switching type having a plurality of memory array banks provided in a memory chip which can be switched from one to another for storage operation. The semiconductor memory device includes: a plurality of memory arrays in the memory array banks; an input/output circuit for transmitting information data between the memory arrays and the outside; a data bus for connecting between the memory arrays and the input/output circuit; and N-channel transistors provided across the data bus. The data bus consists of a plurality of adjacent lines. Each of N-channel transistors is connected at their drain to the corresponding lines of the data bus while at their source to the ground. When a multi-bit test is commenced for writing and reading data on the memory arrays, the N-channel transistors are turned on to connect the lines of the data bus to the ground.
摘要:
The present invention can provide a polymer film having an Ra (arithmetic average roughness) of 0.5 μm to 2.5 μm, an Ry (maximum height) of 3 μm to 11 μm, an Rz (ten-point average height) of 3 μm to 8 μm, and a light transmittance of 85% or higher. A preferable embodiment of the present invention can provide, at the same time, an optical diffusion function, an improved luminance, a transmittance and the like which are of a sufficient level not realized conventionally. In a still preferable embodiment, Sm (average concave-concave/convex-convex interval) of 90 μm to 160 μm and the average inter-local peak interval (S) is 5 μm to 15 μm.
摘要:
A process for producing a carboxylated compound, which comprises reacting a carbonyl compound with hydrogen peroxide in the presence of an organo-arsenic acid of the formula (1), ##STR1## wherein: R.sup.1 is a C.sub.1 -C.sub.12 alkyl group which may be substituted or an aryl group which may be substituted,R.sup.2 is a hydroxyl group or the same group as that which defines R.sup.1,or alternatively, R.sup.1 and R.sup.2 may bond to each other to form a five-membered or six-membered ring together with As atoms to which these groups are bonded, andthe substituent(s) substituted on the above groups is/are selected from hydroxyl, carboxyl, carbonyl, sulfonyl, sulfonium, an amino group, an ammonium group, an alkyl group, an alkoxyl group and a halogen atom,while a water concentration in a reaction system is maintained at not more than 2% by weight, thereby to form a corresponding carboxylated compound.
摘要:
Disclosed is a film suitable for improvement of luminance, contrast and view angle of a liquid crystal display. Specifically disclosed is a retardation film having a thickness of 30-500 μm, a light transmittance of not less than 85%, and an Nz factor of not less than 10.
摘要:
A method of producing a polycarbonate excellent in the hue, the thermal stability, and the electrolysis stability by supplying a polycarbonate obtained by a transesterification method to an extruder having vent(s), melting the polycarbonate, and adding an acidic compound to the molten polycarbonate followed by kneading to continuously devolatilize low molecular weight compounds remaining in the polycarbonate. Better result is obtained by adding water to the kneaded mixture of the polycarbonate and the acidic compound before devolatilizing the low molecular weight compounds.
摘要:
A photosensitive polyimide precursor composed of the structural units (A) represented by the following general formula (I) and the structural units (B) represented by the following general formula (II), in which the ratio of the molar quantity of the structural units (A) to the sum of the molar quantity of the structural units (A) and that of the structural units (B) is 0.01 or greater, and having a viscosity of 100 cP or above as measured at 25.degree. C. in the state of a 10% by weight solution in N-methylpyrrolidone: ##STR1## wherein R.sub.1 represents a tetravalent aromatic hydrocarbon residue; R.sub.2 represents a divalent aromatic hydrocarbon residue; X, identical or different represents a halogen or an alkyl group; and m represents 0 or an integer from 1 to 4. The photosensitivity of the present photosensitive polyimide precursor is about 20 to 100 times that of conventional products. After heat dehydration cyclization, it shows a heat resistance of 400.degree. C. or above.