JPS6156272B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a conductive lubricant for discs used in record discs, etc., which are contact-type recording and reproducing media, and its purpose is to frictionally slide the surfaces of records and discs (hereinafter referred to as discs) under extreme pressure. Reduces the coefficient of friction between the contact needle (hereinafter referred to as the needle) that picks up the recorded signal,
The purpose is to prevent deterioration of characteristics and shortening of life due to wear, and generation of static electricity due to friction. Conventionally, plastic materials (for example, copolymers of vinyl chloride and vinyl acetate) have been widely used as materials for audio and video records due to their processability, recording accuracy, mass productivity, and cost. However, when playing a record made of such a plastic material, it is generally confirmed that the contact surface between the record and the stylus wears out due to friction with the stylus, which is made of ultra-hard material such as diamond or sapphire. In audio disks, this wear causes negative effects such as increased acoustic distortion and deterioration of characteristics. Another problem was that static electricity was generated by the friction between the record and the stylus, which caused problems such as attracting dirt and dust in the air and causing the discharge sound to be played back as noise. . In the past, many improvements have been made to solve these problems, including methods for preventing static electricity and removing adsorbed dust, but there have been few examples regarding lubrication. Examples of recent improvements to the friction between records and needles include surface coatings with lubricants such as silicone-based lubricating oil and surfactant materials, and fluorine-based surfactant solutions as methods for modifying the surface of records. There are surface coatings (Japanese Unexamined Patent Publication No. 545456/1983) and coatings using a thin film of polytetrafluoroethylene resin (Japanese Unexamined Patent Application No. 22102/1989), but these methods have problems depending on each case. included, but not complete. In other words, not only do silicone oils and fluorine-based surfactants not provide sufficient lubricity under the conditions of friction between the record and the stylus, but oil-based and liquid coating agents leave the surface viscous even after application. Because of the residual dirt and dust that remains, it becomes a source of noise, and the stability of the frictional force becomes unstable, making tracing conditions unstable. In addition, the method requires a large-scale coating system for tetrafluoroethylene, and the surface resistance of tetrafluoroethylene is 10 ¹⁵ to 10 ¹⁹ Ω・cm, which is among the highest among general resins, and there are problems due to electrostatic charge. There is. The present invention thus eliminates the drawbacks of the conventional methods of lubricating the record and the needle, easily and inexpensively modifies the surface of the record, and provides antistatic and antistatic methods.
The present invention provides a conductive lubricant that forms a strong protective film with excellent lubricity. In general, a surfactant is a substance that dissolves in a liquid and adsorbs from the solution to an interface, significantly reducing interfacial energy (surface tension, interfacial tension), and by its surface active ability, it has properties such as wetting, lubrication, dispersion, etc. It refers to a substance that has cleaning effects, and there are currently a large number of these substances being produced. The above-mentioned record cleaning liquid utilizes the lubricating effect of the surfactant and the static elimination effect due to the lubricating effect or ion conduction. The lubricating effect of surfactants has been utilized for a long time, mainly in the textile industry, and is used to reduce the coefficient of friction at the contact area between fast-moving fibers and jigs. Conventionally, polyhydric alcohols, higher fatty acids, and ester compounds thereof have been used as lubricants for such uses, and recently fatty acid-modified silicones, fluorinated alkyl esters, and the like have been used as high-performance lubricants. The polyoxyethylene alkyl ether used in the present invention is a type of surfactant mentioned above, but the main purpose of the conventional use of polyoxyethylene alkyl ether is for plastic kneading, which takes advantage of its excellent thermal stability. It was for inclusion. Moreover, the number m of polyoxyethylene (POE=C ₂ H ₂ O) added in this case
Most of the number of moles is 1 to 3, and it was thought that as the number of moles increases, hygroscopicity is promoted and the lubricating effect is decreased. Furthermore, it is generally known that when such surfactants are dissolved in a solvent or when multiple surfactants are mixed, properties such as antistatic ability and lubricity change significantly depending on the combination. At the same time, in addition to the above-mentioned characteristics, the adhesion force of the surfactant changes depending on the material (resin) with which the surfactant is used and the friction conditions. The present inventors selected semi-rigid vinyl chloride resin and ultra-high hardness materials such as diamond from among many surfactants.
We have discovered a conductive lubricant for discs that has excellent lubricity and stability of frictional force using an evaluation method that matches the friction conditions when playing records that slide under extreme pressure of 1,000 kg/cm ² . . In addition, in general, anionic, cationic, and amphoteric surfactants have excellent antistatic (static charge neutralizing) effects, and nonionic surfactants are the most effective among these surfactants. It is thought that the antistatic effect is weak. However, regarding the antistatic effect, if the material used is semi-rigid vinyl chloride resin and Freon is used as a solvent, under the typical Japanese weather conditions where the relative humidity is 50 to 60% RH or more, nonionic surfactants cannot be used. It was found that some of the materials had practically sufficient antistatic ability. As described above, the conductive lubricant for disks according to the present invention has excellent lubricating effect and conductivity. The conductive lubricant according to the present invention will be described below with reference to Examples and Comparative Examples. In addition, when actually using the conductive lubricant for disks according to the present invention, the concentration and amount of application will affect the friction coefficient and antistatic effect, and if a large amount is applied, the antistatic effect will decrease, and the friction coefficient will be approximately proportional to the amount of application. However, the proportionality becomes saturated when the amount of coating exceeds a certain level. However, this is not the case when it comes to the stability of frictional force, and as the amount of coating increases, the amount of variation increases. Furthermore, since the state in which the lubricant is applied also affects the stability of the frictional force, it is better to apply a large amount of a low-concentration liquid to achieve more uniform dispersion and better results. For this reason, when the conductive lubricant according to the invention is used in a sprayer (pump or aerosol), the preferred diluent concentration is 0.03 to 0.3% by weight. However, this may not apply depending on the application method, and if special application equipment or wiping jigs are used, the dilution rate with the solvent may be reduced to 0.3% by weight.
Good results can be obtained even with the above conditions. Examples 1 to 7 3, 5, and 7 moles of polyoxyethylene (POE) were added to cetyl alcohol (C ₁₆ H ₃₃ OH)
POE-added cetyl ether with trichloro-trifluoroethane, and POE-added stearyl ether with 1, 3, 5, and 7 moles of polyoxyethylene (POE) added to stearyl alcohol (C ₁₈ H ₃₇ OH) with trichloro-trifluoroethane. diluted and dissolved to 0.05% by weight to prepare a conductive lubricant. Comparative Examples 1 to 5 POE-added alkyl ester (stearate) in which 7 to 11 moles of polyoxyethylene (POE) are added to stearic acid (C ₁₇ H ₃₅ COOH) and fluorinated ester silicone system in which the alkyl ester is fluorinated A lubricant is prepared by diluting and dissolving a surfactant (fatty acid-modified silicone, alcohol-modified silicone) to 0.05% by weight with trichloro-trifluoroethane. Comparative Examples 6 to 8 12, 15, and 23 moles of polyoxyethylene (POE) were added to cetyl alcohol (C ₁₆ H ₃₃ OH),
A lubricant is prepared by diluting and dissolving POE-added cetyl ether to 0.05% by weight with trichloro-trifluoroethane. Comparative Examples 9-10 15 or 20 mol of polyoxyethylene (POE) was added to stearyl alcohol (C ₁₇ H ₃₅ OH)
A lubricant is prepared by diluting and dissolving POE-added stearyl ether to 0.05% by weight with trichloro-trifluoroethane. The antifriction effect and antistatic ability of the lubricants of Examples 1 to 7 and Comparative Examples 1 to 10 were compared using the following evaluation method. (a) Friction reduction effect evaluation method Using the friction force measuring device shown in Figure 1, equal amounts of the lubricant solutions of Examples and Comparative Examples were applied to test piece 1 made of semi-hard vinyl chloride resin, and the solvent was evaporated. After test piece on table 2
A spherical diamond indenter 3 with a tip diameter of 10 μm is applied with a pressure W in the range of 0.5 to 3 g. In this state, when the table 2 is slid at a constant speed, the tensile load F applied to the diamond indenter 3 is measured with a strain gauge 5 fixed to the parallel plate spring 4, and from the tensile load F and the vertical load W, the friction coefficient μ
(μ=F/W) was determined. In Fig. 1, 6 is a holder, 7 is a needle tip height adjustment screw, and 8 is a holder.
is a needle tip height fixing screw, 9 is a fulcrum, and 10 is a load adjustment weight. (b) Evaluation method of antistatic ability Evaluation was performed using a commercially available static honest meter in an atmosphere of 20° C. and 60% RH based on the half-life time (seconds) of the amount of static electricity. The results of the above evaluation are shown in Tables 1 and 2 below.

【table】

[Table] As is clear from Tables 1 and 2 above, Examples 1 to 7 of the present invention are superior in friction coefficient and antistatic ability compared to Comparative Examples 1 to 10. . FIGS. 2 and 3 show output level-frequency characteristics and third-order distortion level-frequency characteristics when the conductive lubricant for disks of the above embodiment is used in an audio disk. In FIGS. 2 and 3, a is the initial characteristic of the audio disk without applying lubricant, b is the characteristic after tracing the audio disk without applying lubricant 100 times, and c is the lubrication characteristic of the embodiment of the present invention. The audio disc coated with the agent
Characteristics after being traced 100 times. d shows the characteristics after tracing an audio disk coated with lubricant of a comparative example 100 times. As is clear from Figures 2 and 3, in audio discs without lubricant, the sound grooves wear out due to friction with the stylus, so in high frequency bands with high recording density, the output level increases as the number of performances increases. At the same time, the distortion of the signal increases due to the deformation of the sound groove. On the other hand, when the lubricant of the present invention is applied, the wear and deformation of the sound grooves is drastically reduced, and the initial characteristics of the audio disc are maintained for a long period of time. FIG. 4 shows the effect of removing dust attracted to the audio disk by static electricity. In Fig. 4, a indicates removal by wiping with a brush type cleaner;
b is a case in which the conductive lubricant of the present invention is also used, whereas with a brush type cleaner, it is difficult to remove dust attracted by static electricity and a large number of noises are generated.
When the lubricant of the present invention is used, the effect of removing dust and dirt is high, so that the number of noises generated is small. The present invention has the above-mentioned structure, and a part of the nonionic surfactant, which was conventionally thought to have poor antistatic effect and lubricating effect, has been modified to form ultra-hard particles such as diamond needles and saphire needles under extreme pressure. Under friction conditions between the material and semi-rigid vinyl chloride resin, it exhibits excellent lubricity, and when made into a Freon (trichloro, trichloroethane) solution, it has sufficient antistatic properties at relative humidity of 50-60% or more. It was discovered that this method has an effect.

[Brief explanation of the drawing]

Figure 1 is a perspective view of an apparatus for determining the friction coefficient of a lubricant, and Figures 2 and 3 are output level-frequency characteristics and third-order distortion of an audio disc coated with the conductive lubricant for discs of the present invention, respectively. FIG. 4 is a diagram showing the level-frequency characteristics, and is a diagram showing the static elimination effect of the conductive lubricant for disks of the present invention. 1...Test piece, 2...Table, 3...
Diamond indenter, 4...plate spring, 5...strain gauge.

Claims (1)

[Scope of Claims] 1. A conductive lubricant for disks containing a diluting solvent and containing a nonionic polyoxyethylene alkyl ether as a main component, wherein the nonionic polyoxyethylene alkyl ether is cetyl alcohol (C ₁₆ H ₃₃ 1. A conductive lubricant for disks, characterized in that 3 to 7 moles of polyoxyethylene are added to OH), and the diluting solvent is Freon. 2. In a conductive lubricant for discs that is mainly composed of a nonionic polyoxyethylene alkyl ether and contains a diluting solvent, the nonionic polyoxyethylene alkyl ether is a mixture of stearyl alcohol (C ₁₈ H ₃₇ OH) and polyoxyethylene. is 1~
7 mol of a conductive lubricant for disks, and further characterized in that the diluting solvent is Freon.