EP0674587A4 - Film de copolyester oriente biaxialement ameliore pour supports d'enregistrement magnetique. - Google Patents

Film de copolyester oriente biaxialement ameliore pour supports d'enregistrement magnetique.

Info

Publication number
EP0674587A4
EP0674587A4 EP93900180A EP93900180A EP0674587A4 EP 0674587 A4 EP0674587 A4 EP 0674587A4 EP 93900180 A EP93900180 A EP 93900180A EP 93900180 A EP93900180 A EP 93900180A EP 0674587 A4 EP0674587 A4 EP 0674587A4
Authority
EP
European Patent Office
Prior art keywords
biaxially oriented
copolyester film
film
bibenzoate
acid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP93900180A
Other languages
German (de)
English (en)
Other versions
EP0674587A1 (fr
Inventor
Cynthia Bennett
E-Won Choe
John Anthony Flint
Bodo Kuhmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Polyester Film GmbH
Original Assignee
Hoechst AG
Hoechst Celanese Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hoechst AG, Hoechst Celanese Corp filed Critical Hoechst AG
Publication of EP0674587A1 publication Critical patent/EP0674587A1/fr
Publication of EP0674587A4 publication Critical patent/EP0674587A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18Manufacture of films or sheets
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/005Shaping by stretching, e.g. drawing through a die; Apparatus therefor characterised by the choice of materials
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29DPRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D7/00Producing flat articles, e.g. films or sheets
    • B29D7/01Films or sheets
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62Record carriers characterised by the selection of the material
    • G11B5/73Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
    • G11B5/739Magnetic recording media substrates
    • G11B5/73923Organic polymer substrates
    • G11B5/73927Polyester substrates, e.g. polyethylene terephthalate
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62Record carriers characterised by the selection of the material
    • G11B5/73Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
    • G11B5/739Magnetic recording media substrates
    • G11B5/73923Organic polymer substrates
    • G11B5/73927Polyester substrates, e.g. polyethylene terephthalate
    • G11B5/73929Polyester substrates, e.g. polyethylene terephthalate comprising naphthalene ring compounds, e.g. polyethylene naphthalate substrates
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62Record carriers characterised by the selection of the material
    • G11B5/73Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
    • G11B5/739Magnetic recording media substrates
    • G11B5/73923Organic polymer substrates
    • G11B5/73927Polyester substrates, e.g. polyethylene terephthalate
    • G11B5/73935Polyester substrates, e.g. polyethylene terephthalate characterised by roughness or surface features, e.g. by added particles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2067/00Use of polyesters or derivatives thereof, as moulding material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/06Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
    • B29K2105/16Fillers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0018Properties of moulding materials, reinforcements, fillers, preformed parts or moulds having particular optical properties, e.g. fluorescent or phosphorescent
    • B29K2995/0024Matt surface
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2367/00Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
    • C08J2367/02Polyesters derived from dicarboxylic acids and dihydroxy compounds

Definitions

  • This invention relates to a biaxially oriented PENBB copolyester film suitable as a base film for a magnetic recording medium. More specifically, this invention relates to a biaxially oriented copolyester film having a high Young's modulus in both the MD and TD directions and being useful as a base film for the production of a magnetic record medium having excellent electromagnetic conversion characteristics as well as improved mechanical strength.
  • Magnetic recording media having a polyethylene terephthalate (PET) film as a base have found wide use, for example, in video tapes audio tapes, computer tapes, and floppy disks.
  • PET polyethylene terephthalate
  • the polyester based film should have a flat surface, good slip, excellent processability, and thin film thickness.
  • portable magnetic recording devices such as an 8 mm video tape
  • the tape is frequently exposed to high temperatures outdoors or inside vehicles. Therefore, the tape for such applications must have both dimensional stability and thermal stability.
  • the PET base film when the PET base film requires a reduction in thickness, it is the usual practice to draw it at a higher ratio in the machine direction (MD) and thus increase its Young's modulus so that the tape has the appropriate strength, but only in the MD direction.
  • MD machine direction
  • Such base film based on polyethylene terephthalate has reduced stiffness in the transverse direction (TD), which makes the tape susceptible to edge damage, folding and/or difficulties with close contact of the reading head to the tape.
  • the substrate films must have higher Young's modulus to permit smaller thicknesses and higher density recording.
  • a higher Young's modulus is necessary to thinner films because of the lower stiffness of thinner film.
  • a tape prepared from such film encounters trouble in traveling or traversing the various heads and cannot withstand repeated brunting. In the case of a video tape, its contact with a rotating cylinder head is not good with the result that the electromagnetic signal is not read properly.
  • European Patent Application No. 199,244 to Teijin Limited discloses a polyethylene terephthalate based film for magnetic recording media. This application discloses stretching the PET film at a high ratio only in the machine direction and thus the resultant product has reduced stiffness in the TD direction and is susceptible to edge damage and uniform contact with the reading head cannot be achieved.
  • U.S. Patent No. 3,008,934 discloses copolyesters containing as acid derived units 4,4'-bibenzoate and a host of other dicarboxylates including 2,6- naphthalic dicarboxyiate. It also discloses oriented fibers and films prepared from these copolyesters, however, biaxially oriented PENBB films are not disclosed or envisioned.
  • An aim of the present invention is to provide a biaxially oriented copolyester base film having many fine protrusions on its surface, which:
  • ( 1 ) has sufficient strength to permit thickness reduction of the magnetic recording media
  • the present invention employs a PENBB copolyester having at least 25 mole percent of its diacid or diester content of 4,4'-bibenzoic acid (or 4,4'- dialkylbibenzoate; alkyl being C 4 -alkyl)
  • a biaxially oriented PENBB copolyester film suitable for use as a magnetic recording medium has the following mechanical properties, namely: a Young's modulus in the machine direction of greater than or equal to 6.5 GPa
  • the oriented copolyester film has - in addition to the above E MD value - the following characteristics: the sum of the Young's modulus values in the machine direction (E MD ) and the transvers direction (E D ) are greater than or equal to 1 2 GPa
  • E M + E TD > 14 GPa.
  • Figure 1 shows a graph of the number of protrusions per mm 2 versus the height of the protrusions in ⁇ m with the distribution curve of the composition disclosed in Examples 1 and 2, along with the line of
  • the biaxially stretched copolyester (PENBB) base film of the present invention can be produced by reacting an aromatic diacid or its diester equivalent with a diol as is known in the art for making polyesters.
  • the copolyester composition (PENBB composition) must contain at least 25 mol-% (based on the total diacid derived components) of the diester or diacid of 4,4'- dialkylbenzoate, preferably 4,4'-dimethylbenzoate or 4,4'-benzoic acid.
  • the remainder diacid derived portion of the copolyester may be formed from other dicarboxylic acids or their ester equivalents, such as terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, 1 ,4- cyclohexane dicarboxylic acid, di-(4-phenyl) acetylene dicarboxylic acid, 1 ,2 di-(4-phenyl) ethene dicarboxylic acid, sebacic acid, malonic acid, adipic acid, azelaic, glutaric acid, suberic acid, succinic acid, and the like, or mixtures of these can be employed in the present invention.
  • Naphthalene-2,6-dicarboxylic acid is the preferred remainder diacid for the copolyester.
  • Suitable diols employed in the present invention include ethylene glycol, diethylene glycol, polyethylene glycol, butane diol, 1 ,5-pentanediol, 1 ,6- hexanediol, neopentyl glycol, 1 , 10-decanediol, cyclohexane dimethanol, and the like.
  • Ethylene glycol is the preferred glycol.
  • Suitable copolyesters of the present invention can comprise, for example, polyethylene terephthalate/4,4'-bibenzoate, polybutylene terepht- halate, 4,4'-bibenzoate, polypropylene terephthalate/4,4'-bibenzoate, polyethylene naphthalate/4,4'-bibenzoate, polyethylene terephthalate/isopht- halate/4,4'-bibenzoate, polyethylene terephthalate/adipate/4,4'-bibenzoate, polyethylene terephthalate/sulfoisophthalate/4,4'-bibenzoate, and the like.
  • the IV value inherent viscosity, as measured in a 1 : 1 weight-ratio mixture of pentafluorophenol and hexafluoroisopropanol at a concentration of 0.2 g/dl and a temperature of 25 ° C
  • the IV value of the PENBB polymer after extrusion be > 0.5 dl/g and preferably > 0.55 dl/g .
  • a polyethylene naphthalate/4,4'-bibenzoate copolyester comprises roughly equimolar (i.e. from about 40 : 60 to 60 : 40 molar ratio) portions of the esters of 2,6-dinaphthalate and 4,4'-bibenzoate, or the diacids of naphthalene-2,6-dicarboxylic acid and 4,4'-bibenzoic acid.
  • the copolyester is obtained by polycondensation of the reaction product of the diacids or diesters with the diol or glycol.
  • the reaction yields monomer or low molecular weight polyester which is subsequently subjected to the polycondensation reaction in the presence of a catalyst an optionally stabilizers, antioxidants, delusterants, pigments, antistatic agents, etc.
  • Suitable catalysts may be antimony, manganese, cobalt, magnesium, zinc, calcium, etc., as are well known in the art.
  • the preferred trans- esterification catalyst, where employed, would be manganese and/or cobalt.
  • the preferred polycondensation catalyst would be antimony compounds. Such catalysts are well known and conventional in the prior art.
  • Tne polyester film of the present invention can be manufactured by an extrusion process.
  • the polyester resin is first heated to a molten state and then extruded through a wide slot die in the form of an amorphous sheet onto a polished, revolving casting drum.
  • the amorphous sheet extrudate is rapidly cooled or "quenched " to form a cast sheet of polyester.
  • the cast polyester sheet is removed from the casting drum and axially stretched in one direction, either in the direction of the film travel (machine direction, MD) or perpendicu ⁇ lar to the machine direction (transverse direction, TD), while being heated to a temperature between the glass transition temperature and about 30 ° C above the cold crystallization temperature (both temperatures can easily be measured on the films by differential scanning colorimeter (DSC).
  • the copolyester film of the present invention is biaxially oriented, i.e. stretched in both the machine direction and the transverse direction.
  • the total stretch ratio in the machine direction and the transverse direction is between 1 :2 and 1 : 10, preferably between 1 :2.5 and 1 :5.
  • the product of the total stretch ratio should be between 1 to 30 and preferably and between 5 to 20.
  • Biaxial drawing is performed such that the birefringeance is ⁇ 0.2, preferably ⁇ 0.1 to ensure adequate isotropic properties.
  • Birefringeance as mentioned herein is the absolute value of the difference between the maximum and minimum refractive indices in the plane of the film, as measured on common instruments such as Abbe refractometer, optical bench or compensators.
  • a heat setting step occurs to lock in the properties of the film.
  • the heat setting occurs at a temperature between the cold crystallization temperature and the melt temperature of the copolymer composition.
  • the film may be wound on a roll, or in some cases surface treatment of the film such as corona treatment, plasma or flame treatment may be employed before winding the film on the roll, particularly where the film will be further coated with a primer coating, for example.
  • surface treatment of the film such as corona treatment, plasma or flame treatment may be employed before winding the film on the roll, particularly where the film will be further coated with a primer coating, for example.
  • biaxially oriented PENBB co ⁇ polyester film is characterized by the following properties, namely: a Young's mo ⁇ uius in the machine direction of greater than or equal to 6.5 GPa
  • the film has the characteristics: the sum of the Young's modulus values in the machine direction (E MD ) and the transverse direction (E TD ) are greater than or equal to 1 2 GPa
  • E MD + E TD ⁇ 14 GPa - a distribution curve representing the relationship between the number of protrusions per surface area (y/mm 2 ) and the height of the protru ⁇ sions (x ⁇ m), such that the portion of the curve above 20 protru ⁇ sions/mm 2 crosses the line of log 10 y -1 8 x + 3.7 twice (c.f.
  • copolyester film of this invention has been surface-roughened by the inclusion of many fine inert particles being incorporated into the molten polymer to impart good slip.
  • a copolyester firm having a Young's modulus in the longitudinal direction of at least 6.5 GPa, preferably at least 7 GPa, especially preferably at least 7.5 GPa is suitable as a base for electromagnetic recording media.
  • PENBB copolyester of the present invention
  • PET film higher machine draw ratios are required to impart a higher MD modulus.
  • the inclusion of fine particles in the film produces protrusions in the surface of the film, which prevent the film from sticking or blocking when run over rollers or wound on a roll. While good slip is required for a tape, excessive roughness is detrimental to the recording characteristics, most especially in higher density recording, where large protrusions cause defects and drop-outs in the recording. Therefore, the surface topography of the film, i.e. the size and distribution of the surface protrusions, is important for the performance of the tape substrate. A plot of the number of surface protrusions (y/mm 2 ) versus the height of these protrusions (x in ⁇ m) is a useful description of the surface topography
  • ⁇ og-o y -1 8x + 3.7 twice, once before the peak value and once after.
  • the height (x) of the protrusions and the number of the protrusions (y* mm 2 ) are obtained by measuring in accordance with the described procedures below.
  • a three-dimensionally image of the profile of protrusions on the film surface is made with a three-dimensional roughness tester (Hommel tester) under the following conditions: stylus diameter : 2 ⁇ m stylus pressure : 30 mg measuring length : 1 mm sampling pitch : 2 ⁇ m cutoff : 0.25 mm magnification in the longitudinal direction : 20,000 magnification in the transverse direction : 200 scanning : 1 50 lines.
  • the standard level (0 level) of the plane of the profiles is determined in accordance with European Patent Application No. 1 99, 244.
  • the film of the present invention have a surface roughness (R a ) of not more than 1 2 nm as stated previously. If the surface roughness (R a ) of the copolyester based film is larger than 1 2 nm, the surface of the magnetic recording media applied to the copolyester film cannot retain the sufficient electromagnetic conversion characteristics.
  • the preferred surface roughness should not be more than 10 nm, and especially preferred surface roughness is between 8 to 4 nm.
  • the surface roughness (R a ) of the film is measured by the procedure described in European Patent Application No. 1 99,244 with the equipment previously descrioed.
  • the use of the copolyester PENBB allows the production of film with suitable low shrinkage values without the use of special MD relaxation techniques and procedures.
  • Longitudinal shrinkage of less than or equal to 0. 1 percent after exposure at 70 ° C under no load can be obtained, which gives high quality magnetic recording media.
  • Low shrinkage in both the MD and TD directions as well as high Young's modulus in both the MD and TD directions result in a highly dimens.onally stable film having a substantial reduction in edge damage or distortion of the magnetic recording media.
  • the film composition In order to provide good handling and winding properties, the film composition must be such thai the surface is rough. This can be achieved by incorporating fine inert insoluble particles into the film.
  • inert it is meant any particle which does not react with the monomer, polymer or coating during the manufacture of the polymer, the film or the tape.
  • fine particles to the monomers before or during polycon ⁇ densation or to the polymer before extrusion is the typical procedure known in the art.
  • inert fine particles either in agglomerated form, or finely dispersed form can be kaolin, talc, silica, carbonates of magnesium, calcium, or barium; sulfates of calcium, or barium; phosphates of lithium, calcium, or magnesium; oxides of aluminum, silicone, titanium, or zirconium, or mixtures of these; lithium fluoride, carbon black, and the organic acid salts of calcium, barium, zinc, and manganese.
  • fine particles made of crossiinked polymers such as polystyrenes, polyacrylates, and polymetha- crylates. The particles may be all of one type or mixtures of several types.
  • the shape of the particles can be irregular, flaky, spherical, or elongated, preferably spherical.
  • the hardness, density, and color of the particles is immaterial.
  • the average size of the particles should be less than 10 ⁇ m preferably less than 3 ⁇ m, still more preferably less than 2 ⁇ m. Silicone dioxide, titanium dioxide and calcium carbonate are especially preferred.
  • the inert solid fine particles preferably have an average particle diameter of 0.05 to ' 0.6 mm, especially 0.08 to 0.4 mm.
  • the amount of inert solid fine particles to be incorporate ⁇ into the copolyester is generally 0.01 to 1 .5 percent by weight, preferably 0.03 to 1 percent by weight, especially preferably 0.05 to 0.6 percent by weight, based on the weight of the copolyester.
  • the copolyester film of the present invention generally has a thickness of 2 to 1 2 ⁇ m and contains many fine protrusions on its surface. However, no large protrusions exist and the high Young's modulus and excellent dimensional stability produce a superior film for magnetic recording media of high quality.
  • a magnetic recording layer can be formed on the base film and by any of the well known techniques and materials known in the prior art. Producing magnetic recording media from the copolyester based film of the present invention is not a part of the present invention.
  • the Young's modulus was determined by obtaining a film sample 1 5 mm wide and 1 5 cm long was stretched by a Zwick universal tensile tester with an interchuck distance of 100 mm at a head speed of 10 mm per minute. The modulus of the sample was calculated from a tangent to the rising part of the load-elongation curve generally taken between 0.4 to 0.6 percent of the elongation .
  • the following examples illustrate the present invention in greater detail.
  • EXAMPLE 1 10 parts of silica (average particle diameter 0.1 5 ⁇ m) is added to 90 parts of ethylene glycol and are mixed to form a slurry.
  • the pellets are further polycondensed for 20 hours at 240 ° C under vacuum in the solid phase. Thereafter, the inherent viscosity is 1 .1 dl/g. As expected, no T 0 or T cc are discernable in the DSC recording for the crystalline granules.
  • the melt point (T m ) temperature is 281 ° C.
  • EXAMPLE 2 The PENBB pellets from Example 1 containing 0.2 percent by weight silica particles are melted in an extruder at 280 ° C to 320 ° C and extruded through a die slot onto a chill roll at 30 "C. A 120 ⁇ m thick amorphous film is removed from the chilled roll and stretched 3.5 times in the MD direction at 140 ⁇ C, then stretched 3.5 times in the TD direction at 140 - C. The copolyester film is subsequently heat set at 260 ° C for 10 seconds. The resulting mechanical properties of the resulting 10 ⁇ m thick film are:
  • the distribution of the heights of the protrusions and the number of protrusions on the film surface is as shown in curve A of Figure 1.
  • the surface roughness (R a ) is about 8 nm.
  • Example 2 is repeated except that 0.3 percent by weight of titanium dioxide having an average particle diameter of 0.4 ⁇ m is added instead of the silica. To incorporate the proper amount of titanium dioxide into the polymer prepared as in Example 1 , 23 parts of the titanium dioxide slurry are added.
  • the properties of the film are substantially the same as those set forth in Example 2.
  • the distribution curve of the film is shown as curve B in Figure 1 . Because of the larger average particle diameter of the titanium oxide, the film surface is coarser than the film of Example 1 .

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)

Abstract

L'invention concerne un film substrat amélioré pour bandes magnétiques. Le film de base est un film de PENBB orienté biaxialement, ou plus exactement un film de copolyester orienté biaxialement contenant l'unité structurelle (I) (bibenzoate, BB). Ce type de film contenant des particules présente un module amélioré dans le sens machine et transversal et des protubérances superficielles dont la hauteur coupe deux fois la ligne de log10 y = -18x + 3,7.
EP93900180A 1992-12-09 1992-12-09 Film de copolyester oriente biaxialement ameliore pour supports d'enregistrement magnetique. Withdrawn EP0674587A4 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1992/010711 WO1994013483A1 (fr) 1992-12-09 1992-12-09 Film de copolyester oriente biaxialement ameliore pour supports d'enregistrement magnetique

Publications (2)

Publication Number Publication Date
EP0674587A1 EP0674587A1 (fr) 1995-10-04
EP0674587A4 true EP0674587A4 (fr) 1996-02-28

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP93900180A Withdrawn EP0674587A4 (fr) 1992-12-09 1992-12-09 Film de copolyester oriente biaxialement ameliore pour supports d'enregistrement magnetique.

Country Status (2)

Country Link
EP (1) EP0674587A4 (fr)
WO (1) WO1994013483A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7384690B2 (en) 2002-01-10 2008-06-10 Toray Industries, Inc. Biaxially oriented thermoplastic resin film

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3008934A (en) * 1958-07-28 1961-11-14 American Viscose Corp Filament and film forming interpolyesters of bibenzoic acid, certain aromatic acids and a dihydric alcohol
EP0580093A1 (fr) * 1992-07-22 1994-01-26 Hoechst Aktiengesellschaft Feuille mince selon un double axe contenant des couches de polyéthylènenaphtalatebibenzoate (PENBB), procédé de préparation de ces feuilles et utilisation de celles-ci

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57189823A (en) * 1981-05-20 1982-11-22 Toray Ind Inc Production of polyester film
DE3368806D1 (en) * 1982-03-10 1987-02-05 Toray Industries Laminated film and magnetic recording medium made therewith
US4539389A (en) * 1983-03-30 1985-09-03 Teijin Limited Biaxially oriented polyester film
US4833024A (en) * 1987-04-03 1989-05-23 W. R. Grace & Co. Low shrink energy films
US5096733A (en) * 1989-10-30 1992-03-17 The United States Of America As Represented By The Secretary Of The Dept. Of Health And Human Services Prevention of the acute cytotoxicity associated with silica containing minerals

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3008934A (en) * 1958-07-28 1961-11-14 American Viscose Corp Filament and film forming interpolyesters of bibenzoic acid, certain aromatic acids and a dihydric alcohol
EP0580093A1 (fr) * 1992-07-22 1994-01-26 Hoechst Aktiengesellschaft Feuille mince selon un double axe contenant des couches de polyéthylènenaphtalatebibenzoate (PENBB), procédé de préparation de ces feuilles et utilisation de celles-ci

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO9413483A1 *

Also Published As

Publication number Publication date
WO1994013483A1 (fr) 1994-06-23
EP0674587A1 (fr) 1995-10-04

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