SE175551C1 - - Google Patents

Description

Inventors: W Abeck, A Ossenbrunner, H Klockgether, J Geiger and H Schnell Priori et begtird frdn 3 November 1956 (Federal Republic of Germany) The present invention relates to both magnetic recordings.

Magnetizable record carriers, commonly used for magnetic recording and reproduction of sound and other fluctuating signal energy, usually consist of a non-magnetic carrier with a lacquer layer in which magnetizable particles are dispersed.

Magnetizable recorders are known in which the bars for the recording layer consist. of a vast area of various film-forming plastics, e.g. cellulose esters, cellulose ethers, polyvinyl chloride, polyurethanes, polyesters and polyamides. These associations have avail anyants as binders for magnetizable substances. However, it has been found that these plastics do not fully satisfy the highest technical requirements regarding mechanical strength, mechanical and chemical resistance, able to withstand higher temperatures and dimensional stability.

It has now been found that magnetizable recorders which meet the highest requirements can be obtained if the carrier for the magnetizable layer or the binder for the magnetizable substances or baths consist of a thermoplastic polycarbonate made from di- (monohydroxyaryl) alkanes , preferably 4,4'-di- (monohydroxyaryl) alkanes.

Sa.clana polycarbonate can be prepared, for example, by reacting practically equimolecular amounts of di- (monohydroxyiaryl) alkanes and bis-chloro-carbonic acid esters of di (monohydroxyiary1) -alkanes or di- (monohydroxyiary1) -alkanes with phosgene or with carbonic acid diesters . Mixtures of different di- (monohydroxyarylpalkanes and mixtures of dimonohydroxyaryl) alkanes and other dihydroxy compounds can also be used to prepare the polycarbonate.

Examples of polycarbonate which are particularly suitable are those obtained using the following dimonohydroxyarylalkanes: 4,4'-dihydroxy-diphenylmethane, 4,4'-dihydroxy-diphenyl-dimethylmethane, 4,4'-dihydroxy-diphenylmethane. 1,1-cyclohexane, 4,4'-dihydroxy-3,3'-dimethyl-diphenyl-1,1-cyclohexane, 2,2'-dihydroxy-4,4'-di-tert-butyldiphenyl-dimethylmethane, 4.4 '-Clhydrohydroxy-diphenyl-3,4-n-hexane, 2,2- (4,11'-dihydroxy-diphenyl) -3-methyl-butane, 2,2- (4,4'-dihydroxy-diphenyl]-hexane 2,2- (4,4'-dihydroxy-diphenyl) -4-methyl-pentane, 2,2- (4,4'-dihydroxy-diphenyl) -heptane, 4,4- (4,4'-dihydroxy -diphenyl) -heptane and 2,2- (4,4'-dihydride-diphenyl) -tridecane.

The high molecular weight polycarbonates based on 4,4'-di- (monohydroxy-aryl) alkanes are represented by the following general formula:. R'0, \ / 11> --- K — X— / \ —o — o- \ / / \ R'R'R'R 'dar R, X represents a group - C - or -, C 1 1 = 12z R, and R, denote hydrogen atoms, branched or unbranched monovalent carbon radicals having up to 10 carbon atoms, monovalent alicyclic radicals, monovalent or aliphatic radicals, phenyl or furyl radicals, Z denotes an atomic grouping which together with adjacent carbon atoms form an alic, 2 '- R' denotes a hydrogen atom, a monovalent, branched or unbranched aliphatic carbon radical having up to 5 carbon atoms, or a monovalent alicyclic or aromatic hydrocarbon radical, and n denotes an integer greater than 20, preferably stone over 50.

For the preparation of the polycarbonate coffee mixtures of different dimonohydroxyaryl alkanes as well as mixtures of dimonohydroxyaryl alkanes with other dihydroxy compounds are also used, e.g. aliphatic, alicyclic dihydroxy compounds as well as also aromatic dihydrode compounds of a kind other than those mentioned above.

As examples of the accompanying dihydroxy compounds which may be used in accordance with the present invention, the following may be exemplified: Aliphatic dihydroxy compounds, e.g. ethylene glycol, diethylene glycol, triethylene glycol and higher ethylene glycols, thiodiglycol, ethylene dithiodiglycol, the di- and polyglycols prepared from 1,2-propylene oxide, o-, m- or p-xylylene glycol, 1,3-propanediol, 1, 3-butanediol, 1,4-butanediol, 2-methyl-1,3-propaneciol, 1,5-pentanediol, 2-ethyl-1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, 1- hexyl-1,3,3-hexanediol and 1,10-decanediol, alicyclic dihydroxy compounds, e.g. 1,4-cyclohexanediol, 1,2-cyclohexanediol, 2,2- (4,4'-dihydroxy-dicyclohexylene) -propane and 2,6-dihydroxydecahydronaphthalene as well as aromatic dihydroxy compounds, e.g. hydroquinone, resorcinol, pyrocatechol, 4,4'-dihydrocoddiphenyl, 2,2'-dihydroxydiphenyl, 1,4-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 1,2-dihydroxynaphthalene, 1, 5-dihydroxynaphthalene, 1,2-dihydroxyanthracene, 2,2'-dihydroxidinaphthyl-1,1 'and o-, m-, p-hydroxybenzyl alcohol.

These mixed polycarbonates can be produced in the same way as the simple polycarbonates, ie. mixtures of the abovementioned di-monohydroxyarylene alkanes with other dihydric compounds of the above kind can be reacted with carbonic acid derivatives belonging to a group comprising carbonic acid diesters, in particular diaryl esters, phosgene and bis-chlorocarbonic acid esters of dihydroxy compounds.

Particularly suitable polycarbonate can be obtained, for example, from 4,4'-dihydroddiphenyl-dimethylmethane or from 4,4'-dihydroxydiphenylmethyl-methylmethane or from a mixture of 95% 4,4'-clihydroxydiphenyl-dimethylmethane and 5% 4.4 '-dihydroxydiphenylmethane, or a mixture of 90% 4,4'-dihydroxydiphenyl-dimethylmethane and 10% 4,4'-dihydroxydiphenyl-1,1-cyclohexane.

The magnetizable recorders made of said polycarbonate can be characterized by excellent mechanical properties. In their unstretched state, their tensile strength is practically equivalent to that of an acetylcellulose film. The extensibility and impact strength are significantly higher. By stretching, a tear-resistant strength can be obtained, which is equivalent to that of polyesters, made from terephthalic acid and glycols, and at the same time a good stretchability and impact resistance.

In addition, it should be emphasized that these good mechanical properties are reversed in the unstretched state, and when the bars are exposed to temperatures of up to about 160 ° C for a relatively long time, when such bars had been stored at 140 ° C in air, one thus does not detect any decrease in the mechanical properties even after six weeks. In addition, the bars have excellent resistance to the effects of light, even ultraviolet radiation, as well as to the effects of air and moisture. The water absorption is extremely low (0.5% or less), so the film has excellent dimensional stability even in the moist state.

Compared with an acetylcellulose carrier, the films produced from polycarbonate have a higher half-strength factor, in particular higher resistance to egg-ripening, higher resistance to heat and dead & no brittleness, as well as greater resistance to moisture and therefore less elongation in a moist condition.

Compared to polyvinyl chloride, polycarbonate foils have a higher heat resistance, so they have less tendency to become thermoplastic.

Compared with polyethylene terephthalate foils, soft polycarbonate foils are significantly better under the influence of solvents, so that good adhesion of the darpa cast layer is achieved.

Since the polycarbonates to be used in accordance with the present invention are easily soluble in a series of solvents, including low-boiling solvents, foil can be produced by conventional casting methods on a belt or cylinder machine, the advantages of this method, namely the formation of foils with uniform thickness and optical clarity in the interior and ph surface are fully utilized. After thorough interpretation, the raw material is introduced into a container with stirrer, preferably arranged to be operated at high speed, and dissolved in a release agent, e.g. methylene chloride, sh. that the solution has a viscosity of about 50,000 cP. It is possible to add small amounts of higher boiling point solvents, which solvents do not necessarily have a good dissolution capacity for the plastic (chloroform, propyl acetate and butyl acetate). Depending on the type of film desired, it may turn out to be difficult to add small amounts of plasticizer. It is of course also possible to add the dyes or pigments to the solutions or melts in the polycarbonate.

The magnetizable layer can be applied to a polycarbonate carrier prepared in this way, and the binders used can be made of polycarbonate or other film-forming plastics, e.g. cellulose esters, mixed cellulose esters, cellulose ethers, polyvinyl chloride, polyamides, polyurethanes, e.g. reaction products between organic isocyanates having two or more functional groups and polyhydroxy compounds, polyesters, film-forming polymers or copolymers, which are derived from ethylene-saturated monomers and / or aliphatic conjugated dienes having 4 to 6 carbon atoms, which attracted optional materials in the preparation of tape recorders.

Acetals, which are made from linear organic, hydroxyl group-containing polymers and aldehydes, also have very good properties as binders for the magnetizable ones. the particles.

Particularly suitable are 1) linear organic polymers containing hydroxy groups and 2) aromatic aldehydes containing at least one sulfonic acid group which is at least partially neutralized by alkali metal. The effective units in these components are karma aterges of the following form: - CH 2 - CH - CH 2 - CH - X ddr R 1 represents an aryl group, e.g. a phenyl or naphthyl group substituted with at least one sulfonic acid group, the latter being neutralized by alkali metal, e.g. sodium, potassium.

Suitable polymers for the preparation of the above-mentioned acetals are, for example, polyvinyl alcohol (molecular weight preferably about 10,000,000,000,000), polyvinyl alcohols which contain acyl groups, e.g. acetyl groups, propionyl groups, partially hydrolyzed copolymers of vinyl chloride and organic vinyl esters, e.g. vinyl esters, as well as further ethylenated monomers, e.g. acrylic acid, methacrylic acid, fumaric acid, maleic acid, maleic anhydride, esters of said acids with aliphatic alicyclic and arylaliphatic alcohols, e.g. methyl, propyl, butyl, cyclohexyl, benzyl alcohol, aromatic monovinyl compounds, e.g. styrene, vinyl alkyl ethers, ethylene, propylene and other ethylene-saturated aliphatic pistons. These polymers preferably contain hydroxy groups in such an amount that after acetalization with the aromatic aldehydes products are formed with a sulfur content of 4-10% by weight, the sulfur content being derived from the sulfonic acid groups of the aldehydes. The above-mentioned acetals can furthermore be obtained by reacting polymers of an organic vinyl clay, e.g. polyvinyl acetate, in alcohol solution with an aldehyde sulfonic acid, the acetalization entering while binding of ester group one.

Suitable aldehydes for the preparation of the abovementioned acetals are, for example, benzaldehyde monosulfonic acid, benzaldehyde disulfonic acid, the corresponding derivatives which are substituted in the phenyl chain by alkyl or halogen groups, e.g. tolylaldehyde sulfonic acid. It is a further object of the invention to introduce into the polymers, in addition to the above-mentioned aldehyde sulfonic acid, aliphatic, aromatic or arylaliphatic aldehydes which are free Iran sulfonic acid groups or other reactive groups, e.g. acetaldehyde, butyraldehyde, benzaldehyde, chlorobenzaldehyde, tolylaldehyde. The latter aldehydes are preferably introduced into the polymers in amounts of 0.1 to 3 moles, shaved. 1 mole of an aldehyde sulfonic acid. The acetals of the present invention are prepared per se.

The components are paforas in the form of 10-15% solutions in water or methanol or mixtures of hada, and additional organic solvents can be added, e.g. dioxane. Mineral acids are used as catalysts, e.g. hydrochloric acid or sulfuric acid, in an amount of about 1-5%, calculated on the components intended for sale. The reaction mixture is melted at about 60-70 ° C.

Compared with foils of polyvinyl chloride and polyesters, the foils produced from polycarbonate can be characterized by being easily softened on their yarns with polar solvents, for which a very good bonding effect is obtained when the iron oxide-containing casting is required, without the need for intervening. .

Furthermore, it is possible to use cellulose esters, mixed cellulose esters, cellulose ethers, polyvinyl chloride, polyamides, polyurethanes, polyesters or other known film-forming compounds as a binder and to use polycarbonate as a binder for the magnetizable material.

The composition of the solution used for the production of the magnetizable layer depends partly on the binder and partly on the film-forming plastic in the carrier. For the production of the magnetizable layer, one can use which of the ferromagnetic substances heist, e.g. iron oxides, mixed oxides of double and triple jam, e.g. γ-iron oxide (Fe 2 O 3) or ferrous ferrite (Fe 3 O 4), in which part of the iron may be replaced by other metals such as cobalt, manganese or copper, as well as iron powder. The amount proportions of the magnetizable powder and the binder are kept between about 5: 1, preferably between about 2: 1 and 4: 1.

The polycarbonate bar can also be provided with a magnetizable layer, for example the coin is produced by cathodic atomization of magnetizable materials or by applying such materials by evaporation under high vacuum. Furthermore, it is possible to incorporate the magnetizable powders into the polycarbonate foils and in this way produce a recorder consisting of one layer.

Example 1. 250 g of γ-iron (III) oxide and a solution of 85 g of a polycarbonate prepared from 4,4'-dihydroxy-diphenyl-methyl-methyl-ethyl-methane in 600 ml of ethyl acetate, and 280 ml of carbon tetrachloride is ground for 16 hours in a vibrating mill, after which the 4 lacquer suspension of ferric oxide with the aid of a strip casting device (feed hopper) is cast on a highly polished metal strip in a foil casting machine, so that the magnetizable layer in the dry state has a thickness of 0.005-0.025 mm.

A 17% solution of a polycarbonate obtained from 4,4'-dihydroxy-diphenyl-dimethylmethane in methylene chloride is poured at a second casting stall on the same casting machine on the magnetizable layer, after this layer has just dried on the surface. In the dry state, the cast layer has a thickness of between 0.015 and 0.2 mm, depending on the purpose for which the magnetizable record carrier is to be used. The magnetizable layer has excellent adhesion to the bar and shows a completely smooth surface.

Example 2.

An iron oxide lacquer suspension prepared from 275 g of γ-iron (III) oxide in a solution of 60 g of a mixed acetal, prepared from polyvinyl alcohol, benzaldehyde and the sodium salt of benzaldehyde 2,4-disulfonic acid (consisting of 24% benzaldehyde disulfonate-acetal groups, 36% benzaldehyde-acetal groups (and 30% vinyl alcohol groups) and 18 g of a preselection product between vinyl chloride-vinyl acetate copolymer (consisting of 65% vinyl chloride groups, 27% vinyl alcohol groups and 8% vinyl acetate groups) in 480 ml of methanol and 400 ml of acetone grinding of these constituents in a vibrating mill, is applied by means of a strip casting device to a 0.04 mm thick polycarbonate foil of 4,4'-dihydroxy-diphenyl-dimethyl-methane. The coated film is dried in a hot channel at a temperature of 80 ° C. The magnetizable layer may have a thickness of 0.005-0.04 mm. It adheres sufficiently to the substrate and has a high mechanical hall strength and smooth surface.

Example 3.

A 0.13 mm thick polycarbonate film consisting of 4,4'-dihydroxy-diphenyl-dimethylmethane is coated by the dipping process with a casting solution, which in the manner indicated in German Pat. No. 814,225 is prepared by grinding 460 g of iron (III) oxide with a solution of 110 g of a polyester of 3 moles of adipic acid. and 2 moles of hexanetriol and 2 moles of butylene glycol in 250 ml of ethyl acetate and 200 ml of toluene in a vibrating mill (grinding time 36 hours), to which is added after the grinding a solution of 79 g of an adduct of 3 moles of toluylene lysocyanate with 1 mole of hexane triol in 155 ml of ethyl acetate and 140 ml of toluene. The coated foil is heated in a drying channel to a temperature of 120 ° C. The magnetizable layer (the thickness of which can vary between 0.01 and 0.04 mm) has an excellent mechanical half-strength and good bonding strength with the bar, after the lacquer components have been condensed.

Example 4.

A polycarbonate film of 4,4'-dihydroxy-diphenyldimethylmethane with a thickness of 0.1 mm is coated by means of a strip casting device with an iron oxide lacquer suspension, which is prepared by grinding 186 g of γ-iron (III) oxide with a solution of 112 g of a low viscosity ethanol-soluble nitrocellulose and 42 g of butyl benzyl phthalate in 790 ml of a solvent mixture (ethanol: ethyl acetate: toluene = 1: 1: 1). After p01 the ring is dried at 100 ° C. It has good adhesion, a smooth surface and good mechanical hall strength.

Example 5.

A 0.1 mm thick polycarbonate foil of 4,4'-dihydroxy-diphenyl-dimethylmethane is coated by means of a strip casting device with an iron oxide lacquer suspension obtained by 36 hours of grinding 268 g of yarns (III) oxide with a solution of 50 g cellulose acetate butyrate (42% acetic acid content, 23% butyric acid content) in 810 ml of ethyl acetate and 96 ml of methanol. After piping, the layer is dried at 100 ° C. The magnetizable layer (thickness 0.005-0.05 mm) shows good adhesion to the bar with excellent mechanical half-strength.

Example 6.

A 0.04 mm thick polycarbonate film obtained from 4,4'-dihydroxy-diphenyl-dimethylmethane is coated with an iron oxide lacquer suspension having the following composition: 333 g of γ-iron (III) oxide, 83 g of a copolymer of vinyl chloride and vinyl acetate , 30 g of butyl benzyl phthalate and 844 ml of acetone. The iron oxide was ground for 48 hours in a vibrating mill with the release of the copolymer and the plasticizer. After pouring, the layer was dried at 60 ° C. Magnetizable layers with thicknesses of 0.005-0.05 mm solid satisfactorily against the bar.

Example 7.

A 0.04 mm thick film of polyvinyl chloride is coated by means of a strip casting apparatus with an iron oxide lacquer suspension obtained by 36 hours grinding of 250 g of ferroferrite (magnetite) with a rim of 80 g of a polycarbonate obtained from 4,4 ' dihydroxy-diphenyl-ethyl-methylmethane in 680 ml of chloroform in a vibrating mill. The drying of the palorda layer is carried out at 80-90 ° C. The magnetizable layer adheres satisfactorily to the bar and has a high mechanical half-strength. An acetylcellulose film can be used with similar good results instead of a polyvinyl chloride film.

Example 8.

A 0.02 mm thick polyester film (polyester of terephthalic acid and ethylene glycol), provided with a suitable bonding composition, is coated with an iron oxide lacquer suspension prepared by 36 hours of grinding 1 g of γ-iron (III) oxide with a solution of 40 g of a polycarbonate, prepared from 4,4'-dihydroxy-diphenyl-dimethyl-methane in 940 ml of chloroform in a vibrating mill. After coating, the layer is dried at 80 ° C. This layer adheres strongly to the bar and shows excellent mechanical strength. - -

Claims (1)

Patent claim: Magnetizable recorder, composed of a non-magnetic substrate and a clamed strongly bonded magnetizable layer, consisting of a dispersion of a magnetizable powder in a non-magnetic film-forming binder, can be drawn & ray, that the non-magnetic substrate and / or or the magnetizable layer contains a thermoplastic, high molecular weight polycarbonate, which derives its origin from a di- (monohydroxyaryl) alkane. Request publications: Stockholm 1961. Kungl. Bokt.r. P. A. Norstedt & & Mel% 610089