JPS59112450A - Conductive disc type recording medium - Google Patents

Abstract

PURPOSE:To improve wear resistance of a titled medium and the wear resistance of a reproducing stylus by the constitution wherein conductive carbon black particles are added to a thermoplastic resin contg. a PVC resin and an alkyl aralkyl modified silicone at a specific weight ratio. CONSTITUTION:A conductive disc type magnetic recording medium formed with the pits conforming to information signals apart from each other at prescribed intervals in a spiral shape or on a concentrical circle is constituted by using at least a thermoplastic resin and conductive carbon black particles. The thermoplastic resin contains a PVC resin and the alkyl aralkyl modified silicone expressed by the general formula I and the components thereof are constituted at such ratios at which the alkyl aralkyl modified silicone is incorporated at 0.6-1.2pts.wt. in 100pts.wt. the PVC. The conductive disc type recording medium having excellent wear resistance and particularly the remarkably improved wear resistance of a reproducing stylus is thus produced.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a conductive disk disk, on the surface of which pits corresponding to information signals are formed at predetermined intervals in a spiral or concentric manner. The reproduction principle is based on the presence or absence of pi/nod or the length of the pi/to gap, and all the information on the fluctuation of capacitance obtained between the reproduction needle with a conductive layer formed on the side surface and the conductive disk. The present invention relates to a conductive disk type record carrier, generally referred to as a capacitive type, which can be extracted as a signal.

Conventional Structures and Problems In recent years, as conductive disk type record carriers that can be reproduced using this type of capacitance method, CED type video disks (with guide grooves for playback needles; RCA Corporation, USA), VHD system video disc (no guiding groove for the playback needle; Japan Victor (
Ltd.), AHD format digital audio disc (no guide groove for playback needle 3,-).

; Japan Victor Co., Ltd.) has not announced or is commercially available.

In any of the above methods, the same material composition can be used, and the same can be said for the manufacturing method. Therefore, it goes without saying that the present invention is effective in any system.

Hereinafter, conventional examples of conductive disk type record carriers and their problems will be described.

Conventionally, in the field of the record industry, in order to obtain a disc, for example, a stanopaer whose surface is coated with information signals is used to compression mold a composition mainly consisting of vinyl chloride resin and other additives. It is being produced.

On the other hand, the manufacturing method for capacitive conductive disk-type record carriers requires that the same cross-wire technique and molding technology as used for conventional audio records can be used, and that the disk material has appropriate flexibility and abrasion resistance. For this reason, vinyl chloride-based resin materials are used as resin materials for disc molding.0 However, in such conductive disc-type record carriers, capacitance reading from the disc is possible. A sufficient amount of conductive particles must be mixed into the sample. As a conductive particle, it is easy to process.

It is preferable to use conductive carbon black from the viewpoint of dispersibility, stability, price, etc., and the amount added is required to make the volume resistivity of the disk less than 500 Ω·m, preferably less than several tens of Ω·m. . Furthermore, the difference from conventional audio record materials is that the signals (pits) with a diameter of about 1 micron must be faithfully reproduced by press. The melt fluidity of the composition must also be appropriate, the stambar must be able to be pressed continuously without contaminating the entire disc, and the dynamic friction that occurs between the disc and the recycler needle during disc playback causes damage to the disc and the recycler needle. Quality requirements are higher than for conventional records, such as less wear and damage.

In order to satisfy these quality requirements, many proposals have been made for resin materials as disc materials5. Mixtures of vinyl chloride and chlorinated polyethylene resin, copolymer resins of vinyl chloride and olefins such as ethylene and propylene, and graft polymerization of vinyl chloride to ethylene/vinyl acetate copolymers are known.

Further, as the conductive carbon black, one that has good cross-talkability with the resin material and low electrical resistance is used. When using vinyl chloride resin as the resin material, crosstalk,
Heat stabilizers are used to prevent thermal decomposition of resin materials during extrusion and molding. Furthermore, a lubricant (processing aid) is used to lower the melt viscosity of the resin material and improve moldability. Furthermore, it reduces cross-contact of resin materials, cross-contact machines during molding, and adhesion to the inner wall of the extruder, and improves mold release in press machines.

A lubricant is used to reduce the dynamic friction that occurs between the disk and the playback needle, thereby preventing wear and damage to the disk and playback needle.

Among these, in the conductive disk type recording carrier that is the object of the present invention, the lubricant is extremely selected.
, - important. This is because the relative speed difference between the disc and the playback stylus during disc playback is extremely large (the disc rotation speed is 460 revolutions per minute in the CHD system and 9 rotations per minute in the VHD system).
○Rotation), still playback, slow playback, fast playback,
This is because trick play such as random access playback is required, which is an extremely disadvantageous condition when considering the wear resistance of the disc and the playback stylus.

In general, lubricants are known to be based on inorganic materials or organic materials. Inorganic materials include graphite molybdenum disulfide, etc., while organic materials include higher fatty acids, higher fatty acid salts, higher fatty acid esters, and paraffinic hydrocarbons. compounds, silicone oils (eg dimethylpolysiloxane, methylphenylpolysiloxane, etc.) are known. The selection of lubricants in disc materials should be based on their dispersibility and thermal stability.

Silicone oils such as dimethylpolysiloxane and methylphenylpolysiloxane 7 have been used due to their practical effects. As a result, the wear resistance of the disc has improved considerably, but the wear resistance of the recycled stylus has not been confirmed. The drug was strong and arousing.

OBJECTS OF THE INVENTION An object of the present invention is to provide a conductive disk-type record carrier that has excellent abrasion resistance and has significantly improved abrasion resistance of a reproducing needle.

Structure of the Invention The conductive disk-type recording carrier of the present invention is constructed using at least a thermoplastic resin and conductive carbon black particles, and focuses corresponding to information signals are formed at predetermined intervals in a spiral shape or on concentric circles. and the thermoplastic resin includes a vinyl chloride resin and an alkylaralkyl-modified silicone represented by the general formula,
The component composition ratio is q6 to 1.2 parts by weight of the alkylaralkyl-modified silicone to 100 parts by weight of the vinyl chloride system. The abrasion properties are good, and the abrasion properties of recycled needles can be significantly reduced.

Let us consider the reason why a disc made of a modified silicone all-vinyl chloride resin having an alkyl or aralkyl group in the side chain represented by the general formula (I) has extremely good durability against discs and playback needles. , dimethylpolysiloxane or methylphenylpolysiloxane, the general formula (
Argylaralkyl-modified silico-yrd shown in I)
, R, and R' each have 2 to 15.2 to 4 carbon atoms, and -/゛ has relatively good compatibility with vinyl chloride resin and indicates the degree of polymerization. If the number x + y is 30 to 7o, it means that there will be some bleeding to the surface during use of the disc, and furthermore, a phenyl group has been introduced into a part of the structure, so it is more effective than dimethyl silicone oil. Since it is also advantageous in terms of heat resistance, it is considered to have a large effect as a lubricant, that is, on initial characteristics, durability characteristics, and environmental test characteristics.

DESCRIPTION OF EXAMPLES Hereinafter, the present invention will be specifically explained using examples. Note that all parts mentioned in the following examples indicate parts by weight.

Example 1 Vinyl chloride resin (straight vinyl chloride resin average degree of polymerization 450)...100 parts Chlorinated polyethylene (manufactured by Showa Voltage Co., Ltd., Elasrene 301A; chlorine content 30
%)゛°゛4 parts 41 parts 1f carbon black carburetor, O3x 150A-3, D B P oil absorption amount approx. 3
20cc/10, ;-100g, average grain size 16-181rm, apparent specific gravity approximately o,
13) ・20 parts heat stabilizer (manufactured by Nitto Kasei Kogyo Co., Ltd., N2000; organic tin-based liquid stabilizer) Heat stabilizer B (manufactured by Nitto Kasei Kogyo Co., Ltd., MA300A; diptyltin malate)...・2-part I agent A (manufactured by Henkel Nissui Co., Ltd., Roxiol G";
Diacid acid ester of aliphatic alcohol.

Melting point: 42-46°C...2.0 parts Lubricant B (manufactured by Henkel Nissui Co., Ltd., Roxiol G-70)
; Polymer ester wax, melting point 50-62°C)...
・0.4 part lubricating oil (Toshi Silicono■), 5H-203; ftt
Alkylaralkyl-modified silicone oil represented by formula (I), viscosity 1200 cps, specific gravity 091. Refractive index 1.4
64) - A sample disk was prepared by sufficiently stirring a mixture consisting of 0.7 parts or more using a high-speed stirrer, heating and melting the mixer using a mixer, and then extruding and compression molding.

11beZ Examples 2 to 4 In Example 1, the amount of alkylaralkyl-modified silicone oil, 5H203, added as a lubricating oil was 0.6 parts (Example 2), 0.9 parts (Example 3), and 1.2 parts. Section (Example 4)
A sample was prepared in the same manner as in Example 1 except for the following.

Comparative Example 1 In Example 1, dimethyl silicone oil (manufactured by Tsukushi Resilico-7 Co., Ltd., 5H200; viscosity 50 cps) was used instead of the alkylaralkyl-modified silicone oil as the lubricating oil.
A sample was prepared in exactly the same manner as in Example 1, except that the amount added was 97 parts.

Comparative Example 2 In Example 1, phenyl-modified silicone oil (
All samples were prepared in the same manner as in Example 1, except that Toshi Silicone Co., Ltd. g, 5H550; methylphenyl-modified silicone oil, viscosity 130 cps) was used and the amount added was 0.7 parts.

Comparative Examples 3 to 5 In Example 1, the addition amount i of alkylaralkyl-modified silicone oil, 5H203, as a lubricating oil was 0 parts (Comparative Example 3), 0.3 parts (Comparative Example 4), and 1.5 parts (Comparative Example). 5), all samples were prepared in the same manner as in Example 1 at 1/i1 m.

The samples obtained in the above Examples and Comparative Examples were examined for moldability, image quality, and abrasion resistance of disks and reproduction needles. The results are shown in the table below.

In addition, the volume resistivity values of the samples are all 8 to 12Ω・
It was m.

(Fuj.1 total 6) 14beS゛In the above table, (1) The amount of silicone oil added is 100% of the vinyl chloride resin.
The number of parts by weight of silicone oil added to parts by weight is shown.

(2) The moldability was evaluated using the stanopa during heat compression molding of a disk material with a predetermined composition, stain resistance on the surface of the disk, organic matter of disk warpage, etc.

(3) To determine the wear resistance of the disk, the middle circumferential portion of a sample disk of a predetermined composition was reproduced from steel for one hour, and the presence or absence of deterioration of the reproduced image quality and the degree of damage caused by the reproduction needle on the disk surface were examined.

(4) The life of the regeneration needle was measured by repeatedly reproducing the sample disk over the entire circumference and measuring the time until the length of the regeneration needle decreased by 2.5 parts m.

Effects of the Invention As is clear from the above explanation, the disk-type recording body of the present invention is constructed using a thermoplastic resin and conductive carbon blank particles, and the information signal and the corresponding focus are spiral-shaped. Alternatively, they are formed in the shape of 15 concentric circles spaced apart from each other at a predetermined interval, and the thermoplastic resin includes a vinyl chloride resin and an alkylaralkyl-modified silicone represented by the above-mentioned general formula (I), and the component composition ratio thereof is It is characterized by containing 0.6 to 1.2 parts by weight of the alkylaralkyl-modified silicone per 10 parts by weight of the vinyl chloride resin. It becomes possible to manufacture a conductive disk-type record carrier that has superior wear resistance, especially the wear resistance of the playback stylus, compared to those in which the present invention was added.

Claims (1)

[Scope of Claims] Comprised of at least a thermoplastic resin and conductive carbon black particles, pits corresponding to information signals are formed at predetermined intervals in a spiral or concentric manner, and the thermoplastic resin contains a vinyl chloride resin and an alkylaralkyl-modified silicone represented by the general formula,
The component composition ratio is 0.62 of the alkylaralkyl-modified silicone to 100 parts by weight of the vinyl chloride resin, -
7 to 1.2 parts by weight of a conductive disk type record carrier.