EP0619043A1 - Aufzeichnungsträger mit einem gehäuse und verschlussteil dafür - Google Patents

Aufzeichnungsträger mit einem gehäuse und verschlussteil dafür

Info

Publication number
EP0619043A1
EP0619043A1 EP93902119A EP93902119A EP0619043A1 EP 0619043 A1 EP0619043 A1 EP 0619043A1 EP 93902119 A EP93902119 A EP 93902119A EP 93902119 A EP93902119 A EP 93902119A EP 0619043 A1 EP0619043 A1 EP 0619043A1
Authority
EP
European Patent Office
Prior art keywords
closure part
polyacetal
housing
record carrier
opening
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Withdrawn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
EP93902119A
Other languages
German (de)
English (en)
French (fr)
Inventor
Heiner Goerrissen
Dietrich Saenger
Peter Rieger
Hubert Fehrenbach
Stephanie Schauhoff
Edwin Nun
Detlef Arnoldi
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.)
Emtec Magnetics GmbH
Original Assignee
BASF Magnetics GmbH
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 BASF Magnetics GmbH filed Critical BASF Magnetics GmbH
Publication of EP0619043A1 publication Critical patent/EP0619043A1/de
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
    • G11B23/02—Containers; Storing means both adapted to cooperate with the recording or reproducing means
    • G11B23/03—Containers for flat record carriers
    • G11B23/0301—Details
    • G11B23/0308—Shutters
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
    • G11B23/02—Containers; Storing means both adapted to cooperate with the recording or reproducing means

Definitions

  • the invention relates to a record carrier with a housing which has an opening and a closure part for the opening, the opening being accessible in the open position and not accessible in the closed position by moving the closure part, and the closure part being off Polyacetal material is injection molded part, as well as the closure part itself.
  • EP-A 301811 discloses a microfloppydis or 3.5 "diskette with a closure part made of a plastic, preferably polypropylene.
  • a similar closure part made of a plastic e.g. Polyamide, polybutylene terephthalate (PBT), polyester, polypropylene (PP), polyethylene (PE), polyfluoroethylene (PFET), polyacetal etc.
  • a plastic e.g. Polyamide, polybutylene terephthalate (PBT), polyester, polypropylene (PP), polyethylene (PE), polyfluoroethylene (PFET), polyacetal etc.
  • PBT polybutylene terephthalate
  • PP polypropylene
  • PE polyethylene
  • PFET polyfluoroethylene
  • polyacetal polyacetal
  • the properties of the known closure parts are disadvantageous in that plastic abrasion occurs in polypropylene, which causes serious disruptions in operational and data security, that a plastic with too much filler is relatively brittle and the injection molded parts are so fragile that they are damaged by the Break assembly to the housing and that, due to high shear forces during injection molding, segregation phenomena of the lubricant used and thus mold coating can occur.
  • the invention has set itself the task of forming a recording medium with a housing with a closure part and the latter itself made of plastic so that the above disadvantages of the prior art are avoided.
  • a record carrier having a housing which has at least one opening and a closure part for the opening, the opening being accessible in the open position and not being accessible in the closed position by moving the closure part, and the closure part being made of polyacetal. Part produced by injection molding is released when the closing part consists of a polyacetal with less than 0.1 percent by weight of lubricant.
  • a polyoxymethylene as polyacetal is particularly favorable. 5
  • the most suitable material for the desired injection molded part, the closure part, namely the polyacetal and in particular the polyoxyethylene is selected from the plastic materials mentioned at the outset, although the other materials for the injection molding of thin parts are also suitable for the person skilled in the art Are available (see Plastics Engineering Handbook, Joel Frados, 4th Edition, 1976, p. 647).
  • the polyacetal material can also contain no lubricants at all without disadvantages.
  • the melt index of the polyacetal is expediently between 30 and 150 g / 10 min, preferably 50 to 100 g / 10 min, for all polyacetal plastics.
  • a melt index (MFI) of the polyacetal, in particular of the polyoxymethylene, is particularly favorable is greater than
  • melt index MFI
  • these ranges according to the invention are optimal for achieving economical injection molding conditions, especially for polyacetal, in particular for polyoxymethylene.
  • the polyacetal material can be used for blackening.
  • the closure part can contain about 0.04 to 0.09 percent by weight of carbon black with a primary particle size of ⁇ 30 nm as the color pigment.
  • this also means that dark-colored closure parts are easy to produce and, moreover, the conductivity of the carbon black can advantageously be used for an anti-electrostatic design of the closure part.
  • the recording medium according to the invention in a housing can advantageously be a recording disc in a flat housing, in particular a magnetic disk or microdisk.
  • the recording medium has a magnetic tape in a cassette housing, e.g. is a digital compact cassette (DCC).
  • a cassette housing e.g. is a digital compact cassette (DCC).
  • DCC digital compact cassette
  • the closure part itself has a wall thickness of less than 1 mm, is injection-molded and advantageously consists of a polyacetal, in particular a polyethylene, with a lubricant content of less than 0.1 percent by weight or contains no lubricant at all.
  • the lubricant content can be about 0.04 to about 0.09 percent by weight.
  • the melt index (MFI) should be between about 30 and about 150 g / 10 min, in particular from about 50 to about 100 g / 10 min, and is preferably higher than about 60 g / 10 min, in particular about 75 g / 10 min.
  • the lubricant content based on the thickness of the closure part should be between approximately 0.01 and 0.16 / mm in order to obtain more favorable injection molding results.
  • the closure part can have a carbon black with a mean primary particle size of at most 30 nm as the color pigment.
  • the closure part consists of a U-shaped part with a cross-section of approximately the same length for U-shaped gripping around the housing with a housing opening, at least one window opening being provided in the closure part surfaces for the housing opening.
  • the closure part can also consist of a U-shaped part of cross-section with legs of unequal length for gripping around the housing and can be designed with a back part connecting the legs with at least one window opening for openings on the narrow side of the housing.
  • the thicknesses of the U-shaped parts produced as an injection molded part should be between approximately 0.25 and approximately 0.6 mm, preferably between approximately 0.3 and approximately 0.5 mm, in order to be inexpensive to produce by injection molding additional low material requirements.
  • a floppy disk and a cassette are shown in the drawing as examples for uses of the invention. Show it:
  • FIG. 1 shows a 3.5 "floppy disk with a closure part.
  • FIG. 2 shows a cassette with a closure part
  • FIG. 1 shows an exploded view of a 3.5-inch diskette or microdiskette, which consists of a base housing part 1, a cover housing part 2, a magnetic disk 3 as a recording medium, a slide 4 as a movable closure part and also from the small parts Slider locking spring 5, lifter 6 and Schreibsper ⁇ re 7 there.
  • the magnetic disk 3 has a hub 8 connected to it centrally with the shape of an inverted flat hat.
  • an opening is arranged as an inlet opening 12 for a scanning element.
  • the slider 4 has a U-shaped cross section with legs 13 and 14 of approximately the same length.
  • the window openings are denoted by 15.
  • the middle part of the hub 8 fits with its outer circumference into the circular opening of the bottom housing part 1 for the rotary mounting of the magnetic disk 8 in the housing 1, 2.
  • the entrance opening 12 is only accessible if one of the window openings 15 is above it.
  • closure parts for magnetic disk units are known, for which the present invention can also be used advantageously.
  • FIG. 2 shows a housing 20 of a DCC cassette which is covered on its front side 21 with the front openings 22a and 22b by means of a closure part 23, the openings 22a and 22b are either closed or released, depending on the position of the sliding closure part 23.
  • the closure part 23 or slide has a U-shape, the parts 24 and 25 being of unequal length.
  • window openings 27a and 27b on the back part 26 of the U-shape.
  • the band (not shown) can be operated inside or outside (with the band being pulled out).
  • polyoxymethylene is selected as the plastic material for the production of the closure part (e.g. slide 4).
  • Molding compositions according to the invention made of polyoxymethylene generally contain 50 to 99.9, preferably 60 to 99.8% by weight and in particular 70 to 99.8% by weight of a polyoxymethylene homo- or copolymer.
  • these polymers have at least 50 mol% of recurring —CH 2 0- units in the main polymer chain.
  • the homopolymers are generally prepared by polymerizing formaldehyde or trioxane, preferably in the presence of suitable catalysts.
  • polyoxymethylene copolymers are preferred, in particular those which, in addition to the repeating units -CH 2 -0-, also contain up to 50, preferably 0.1 to 20 and in particular 0.3 to 10 mol% recurring units included R2 R 3
  • R 1 to R 4 independently of one another are a hydrogen atom, a Ci to C 4 allyl group or a halogen-substituted alkyl group having 1 to 4 C atoms and R 5 is a -CH 2 -, -CH 2 0-, a Ci bis
  • cyclic ethers are those of the formula
  • R 1 to R 5 and n have the meaning given above.
  • examples include ethylene oxide, 1,2-propylene oxide, 1,2-butylene oxide, 1,3-butylene oxide, 1,3-dioxolane and 1,3-dioxepane as cyclic ethers as well as linear oligo- or polyformals such as polydioxolane or polydioxepane as comonomers.
  • 0-methylene terpolymers which, for example, by reacting trioxane, one of the cyclic ethers described above, with a third monomer, preferably a bifunctional compound of the formula
  • Preferred monomers of this type are ethylene diglycide, diglycidyl ether and diether from glycidylene and formaldehyde, dioxane or trioxane in a molar ratio of 2: 1, and diether from 2 mol of glycidyl compound and 1 mol of an aliphatic diol with 2 to 8 C-atoates, for example the diglycidyl ethers of ethylene glycol, 1,4-butanediol, 1,3-butanediol, cyclobutane-1,3-diol, 1,2-propanediol and cyclohexane-1,4-diol, to name just a few examples.
  • the preferred polyoxymethylene copolymers have melting points of at least 150 ° C. and molecular weights (weight average) M w in the range from 5000 to 200000, preferably from 7000 to 150,000.
  • End group-stabilized polyoxymethylene polymers which have C-C bonds at the chain ends are particularly preferred.
  • polyoxymethylene (POM) copolymers are preferably used which have a melt index (according to ISO standard 1133) measured at 190 ° C. and 2.16 kg load of at least about 30 g / 10 min.
  • the more favorable range of the melt index is between approximately 40 and 150 g / 10 min, in particular between approximately 50 to approximately 100 g / 10 min and preferably higher than approximately 60 g / 10 min, in particular approximately 75 g / 10 min.
  • the POM copolymer for the closure part of the invention is preferably obtained by copolymerizing formaldehyde or trioxane with 0.5-10% by weight of a comonomer which is selected from the group consisting of ethylene oxide, tetrahydrofuran (THF), 1, 3-dioxolane, 1,3-dioxepane, and 1,3,5-trioxocane.
  • a comonomer which is selected from the group consisting of ethylene oxide, tetrahydrofuran (THF), 1, 3-dioxolane, 1,3-dioxepane, and 1,3,5-trioxocane.
  • the POM homo- or copolymer can also contain 0.01-0.05% of a branching comonomer, selected from the group consisting of the diglycidyl ethers of ethylene glycol, 1,3-butanediol, 1,4-butanediol or 1,6-hexanediols, as well as from diglycerol diformate or diglycerol triformal.
  • a branching comonomer selected from the group consisting of the diglycidyl ethers of ethylene glycol, 1,3-butanediol, 1,4-butanediol or 1,6-hexanediols, as well as from diglycerol diformate or diglycerol triformal.
  • the suitable POM homopolymers and copolymers usually contain stabilizing additives such as phenolic antioxidants (preferably Irganox 245, Irganox 259 or Irganox 1010 from Ciba-Gei
  • Lubricants are selected from the group of fatty acid esters of glycerol or pentaerythritol, silicone oil, paraffins PTFE, alkaline earth metal salts of fatty acids (eg calcium 9-hydroxy stearate, tricalcium dicitrate), ethylene-bis-stearic acid amide, molybdenum disulfide or graphite.
  • fatty acid esters of glycerol or pentaerythritol silicone oil
  • paraffins PTFE alkaline earth metal salts of fatty acids (eg calcium 9-hydroxy stearate, tricalcium dicitrate), ethylene-bis-stearic acid amide, molybdenum disulfide or graphite.
  • Carbon black generally has no lubricating properties - without further additives.
  • the following products can be considered as "carbon black" for dyeing purposes:
  • Commercial carbon black preferably with an average primary particle size equal to or less than 30 nm and a DBP adsorption value equal to or less than 380 ml / 100 g, according to DIN 53601.
  • Manufacturer is, for example the company Degussa AG.
  • DBP adsorption value means dibutyl phthalate adsorption value.
  • the water absorption of the POM copolymer was 0.23 percent by weight at 50% relative humidity (RH) and 23 ° C., and even 0.8 percent by weight when saturated and 23 ° C.
  • POM copolymer of 97% trioxane and 3% 1,3-dioxepane which 0.3% Irganox 1010 and 0.1% of a polyamide (according to Example 5-4 of US 3,960,984) as Stabilizers and 0.3% pentaerythritol tetrastearic acid esters as lubricants.
  • MFI 190 / 2.16 54 g / 10 min.
  • the closure parts were produced on an Arburg Allrounder 320 injection molding machine with 750 kN injection pressure in a single hot runner mold at a melt temperature of 210 ° C and a mold surface temperature of 90 ° C.
  • the closure part was made in one piece, ie in a U-shape, cf. Part 4 in the drawing, manufactured and had the following main dimensions:
  • the related soot Prin ex®90 is a pigment soot that has no lubricant effect. It has even been found that the flowability in a polyoxymethylene deteriorates even in these low proportions of less than 0.1 percent by weight, which means that it acts exactly like a lubricant.
  • closure parts of the tests under a) manufactured with materials and properties according to the invention also show that (with the exception of test 4) relatively low injection pressures were sufficient, so that a sufficient pressure increase for the use of multiple tools is possible.
  • wall thicknesses of such closure parts for the various recording medium systems briefly explained above are in the range from approximately 0.25 mm to approximately 0.6 mm, in particular approximately 0.3 to approximately 0.5 mm. It was found that the ratio of the lubricant content in percent by weight to the thickness of the closure parts is between approximately 0.01 / mm and approximately 0.16 / mm in order to be able to produce optimal closure parts in accordance with economical production and good mechanical properties.
  • MFI '230/5 50 g / 10 min, which contains 10% talc.
  • the closure parts were manufactured by injection molding at a melt temperature of 260 ° C and a mold temperature of 30 ° C. These closure parts show poor sliding properties on the disk housing, which consisted of ABS. Long-term use therefore leads to abrasion, which has a very negative effect on the operational safety of the diskettes. In addition, strong mold was found.
  • closure parts 150 cm 3/10 min, contains no filler.
  • the closure parts were produced by injection molding at 290 ° C. with a mold temperature of 60 ° C. Due to the high water absorption of the polyamide, the dimensions of the closure parts made from this material fluctuate as a function of the air humidity. As a result, the dimensional stability of the parts is not guaranteed, which leads to dust entering the floppy disk in dry weather and jamming of the closure part in wet weather. The closure parts also become too soft when the air humidity is high due to the decrease in rigidity, which considerably impairs the functional reliability.
  • ABS with melt volume index MVI 220/10 35 cm 3/10 min.
  • the closure parts were sprayed at a melt temperature of 265 ° C. and a tool temperature of 80 ° C. These closure parts resulted in insufficient sliding properties and a high degree of abrasion when sliding against the disk housing.
  • the latter is made from polyacetal, in particular polyoxymethylene, with less than 0.1% by weight of lubricant.
  • This closure part can be used with any type of record carrier in housings, in particular magnetic media, with closable housing openings and cassettes with closable front openings.

Landscapes

  • Compositions Of Macromolecular Compounds (AREA)
  • Injection Moulding Of Plastics Or The Like (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
EP93902119A 1991-12-24 1992-12-18 Aufzeichnungsträger mit einem gehäuse und verschlussteil dafür Withdrawn EP0619043A1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE9116064U DE9116064U1 (ja) 1991-12-24 1991-12-24
DE9116064U 1991-12-24
PCT/EP1992/002956 WO1993013527A1 (de) 1991-12-24 1992-12-18 Aufzeichnungsträger mit einem gehäuse und verschlussteil dafür

Publications (1)

Publication Number Publication Date
EP0619043A1 true EP0619043A1 (de) 1994-10-12

Family

ID=6874630

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93902119A Withdrawn EP0619043A1 (de) 1991-12-24 1992-12-18 Aufzeichnungsträger mit einem gehäuse und verschlussteil dafür

Country Status (6)

Country Link
EP (1) EP0619043A1 (ja)
JP (1) JPH07504287A (ja)
KR (1) KR940704045A (ja)
CN (1) CN1075228A (ja)
DE (2) DE9116064U1 (ja)
WO (1) WO1993013527A1 (ja)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0740423B2 (ja) * 1986-03-01 1995-05-01 日立マクセル株式会社 デイスクカ−トリツジ
KR0124147B1 (ko) * 1987-07-29 1997-11-28 나가이 아쯔시 디스크 카트리지
JP3020990B2 (ja) * 1990-03-20 2000-03-15 日立マクセル株式会社 カートリツジ用シヤツタならびにその成形装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9313527A1 *

Also Published As

Publication number Publication date
CN1075228A (zh) 1993-08-11
JPH07504287A (ja) 1995-05-11
KR940704045A (ko) 1994-12-12
DE9116064U1 (ja) 1992-02-20
WO1993013527A1 (de) 1993-07-08
DE9217362U1 (ja) 1993-02-18

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