摘要:
A polycarbonate resin having an improved hue is provided, which is suitable for use as a substrate for transfer type optical recording media such as optical disks. The polycarbonate resin is one obtained by reacting starting materials comprising a dihydric phenol, a carbonate material, and a chain terminator comprising a p-(long chain)-substituted phenol (hereinafter referred to as a para isomer), characterized in that the amount of an o-(long chain)-substituted phenol (hereinafter referred to as an ortho isomer) contained as an impurity in the chain terminator used satisfies the following relationship: ( ortho isomer amount ) ( para isomer amount ) + ( ortho isomer amount ) × 10 6 ≤ 10 ( 0.31 × ( number of C ' s ) + 0.8 ) ( i ) (wherein “number of C's” represents the number of carbon atoms in the substituent organic group of the substituted phenols).
摘要:
A polycarbonate resin having an improved hue is provided, which is suitable for use as a substrate for transfer type optical recording media such as optical disks. The polycarbonate resin is one obtained by reacting starting materials comprising a dihydric phenol, a carbonate material, and a chain terminator comprising a p-(long chain)-substituted phenol (hereinafter referred to as a para isomer), characterized in that the amount of an o-(long chain)-substituted phenol (hereinafter referred to as an ortho isomer) contained as an impurity in the chain terminator used satisfies the following relationship: ( ortho isomer amount ) ( para isomer amount ) + ( ortho isomer amount ) × 10 6 ≤ 10 ( 0.31 × ( number of C ' s ) + 0.8 ) ( i ) (wherein “number of C's” represents the number of carbon atoms in the substituent organic group of the substituted phenols).
摘要:
A polycarbonate resin obtained by polymerizing an aromatic diol and a carbonate-forming compound using a monophenolic compound as a molecular weight modifier, wherein said polycarbonate resin contains from 0.2 to 2% by weight of a low-molecular weight compound represented by formula (I): ##STR1## wherein R.sup.1 represents an aromatic diol residue; and R.sup.2 represents a monophenolic compound residue, and wherein said polycarbonate resin provides less amount of low-molecular weight volatile matters even when heated or injection-molded. When heated at 350.degree. C. under reduced pressure of 1 mmHg for 20 minutes, the proportion of the low-molecular weight compound of formula (I) which volatilizes is not more than 0.2% by weight based on the weight of said low-molecular weight compound of formula (I) present in the polycarbonate resin. When heated at 400.degree. C. under reduced pressure of 1 mmHg for 30 minutes, the proportion of the low-molecular weight compound of formula (I) which volatilizes is not more than 2% by weight based on the low-molecular weight compound of formula (I) present in the polycarbonate resin.
摘要:
The object the present invention is to provide an exterior molding body for automobile which is reinforced by a long fiber, is excellent in mechanical properties such as bending elastic modulus and bending strength, chemical resistance and heat resistance, is lightened, has high designability and is reduced in the anisotropy of linear expansion coefficient of molding body caused by the fiber orientation at filling thereof to a mold.
摘要:
The magnetic head is capable of stabilizing arrangement of magnetic domains in a shield layer of a read-head, preventing variation of characteristics of the read-element and improving reliability. The magnetic head comprises the read-head, in which the read-element is magnetic-shielded by a shield layer. A step-shaped section is formed in a base layer, on which the shield layer is formed, and the step-shaped section corresponds to a border of at least one of domain areas, which are defined by desired magnetic domains to be formed in the shield layer after a magnetizing process.
摘要:
The object the present invention is to provide an exterior molding body for automobile which is reinforced by a long fiber, is excellent in mechanical properties such as bending elastic modulus and bending strength, chemical resistance and heat resistance, is lightened, has high designability and is reduced in the anisotropy of linear expansion coefficient of molding body caused by the fiber orientation at filling thereof to a mold.
摘要:
A large-capacity optical recording medium, comprises a track region having a plurality of tracks arranged along the concentric or spiral grooves, the track region being radially divided into annular zones, and each of the tracks being partitioned into plural sectors such that a number of the sectors per track is constant in each zone but the number of the sectors per track differs between among zones, wherein an address designating a specific track and sector is previously recorded as a plurality of prepits, the track region having a user-track region, in which a user can optically record or readout information, and a pair of control-track regions, radially bracketing said user-track region, the control-track region permitting the user to read out information therefrom but not to record information thereon, and wherein the control-track region located radially inward of the user-track region is provided with medium information tracks in which medium information has been recorded as prepits, and the control-track region located outward of the user-track region has no medium information track and is not used for recording, nor for reading out of user data.
摘要:
An ethylene homopolymer or copolymer comprising ethylene and not more than 10% by weight of an .alpha.-olefin having from 3 to 20 carbon atoms and a fuel tank obtained therefrom are disclosed, said ethylene homopolymer or copolymer having (1) an intrinsic viscosity [.eta.] of from 2 to 6 dl/g, (2) a density of from 0.945 to 0.970 g/cm.sup.3, (3) an R value of from 2.5 to 4, said R value being defined as a .sigma..sub.2 /.rho..sub.1 ratio, wherein .sigma..sub.1 and .sigma..sub.2 mean stress in elongation with a strain at 2 sec and 4 sec, respectively, under a flow at an elongational strain rate .epsilon. of 0.5 sec.sup.-1, and (4) a relationship between high-velocity impact strength (HRI-IZOD) measured at -30.degree. C. and a melt index under a load of 21.6 kg (HLMI) satisfying formula:HRI-IZOD.gtoreq.-log HLMI+1.15The ethylene polymer exhibits high melt tension and excellent molding properties such as uniform stretchability in blow molding to provide molded articles, such as a fuel tank, having excellent mechanical characteristics, such as high stiffness and high impact resistance, and excellent fire resistance.