POLYETHYLENE 2,6-NAPHTHALENEDICARBOXYLATE FILM

• Main Authors: KOBAYASHI, IEYASU, SAEKI, YASUHIRO, CHUUJOU TAKAO, HOSOI, MASAHIRO
• Format: Patent
• Language: English; Japanese
• Published: 13.05.1993
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; GENERAL PROCESSES OF COMPOUNDING; INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULARARTICLES; INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PHYSICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL; WORKING-UP

A biaxially oriented polyethylene 2,6-naphthalenedicarboxylate film which is usable as a base film for magnetic recording media capable of high-density recording, in particular, magnetic tape, characterized in that the numbers of protrusions formed on the surface of the film and meeting the conditions that 1 h < 50 (wherein h is the height, nm, of the protrusion), 50 h < 100 and 100 h fall each within a specified range, that the planar orientation coefficient (NS) and means refractive index (na) of the film satisfy the relation NS 1.607na - 2.434, that the surface roughness (Ra) of the film ranges from 2 to 10 mm, and that the longitudinal heat shrinkage is 0.08 % or less when the film is heat treated at 70 C for 1 hour without any load added. L'invention se rapporte à un film de 2,6-naphthalenedicarboxylate de polyéthylène, à orientation biaxiale, qui est utilisable comme film de base pour des supports d'enregistrement magnétiques haute densité, tels que notamment des bandes magnétiques. Un tel film se caractérise en ce que les nombres de saillies formées sur la surface du film et satisfaisant aux conditions suivantes: 1 h < 50 (où h représente la hauteur, nm, de la saillie), 50 h < 100 et 100 à h, sont chacun compris à l'intérieur d'une plage spécifiée, en ce que le coefficient d'orientation planaire (NS) et l'indice de réfractation moyen (na) du film satisfont à la relation NS 1,607 na - 2,434, en ce que la rugosité de surface (Ra) du film est comprise entre 2 et 10 mm, et en ce que le thermorétrécissement longitudinal est de 0,08 % au maximum, lorsque le film est traité à chaud à une température de 70 °C pendant une heure, sans adjonction d'aucune charge.