JPH023427B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vinyl chloride resin composition for capacitive video discs. Many resin compositions for manufacturing video discs have already been studied and attempts have been made to put them into practical use. In particular, the resin for capacitive video disks must be conductive, have excellent wear resistance, have a relatively high heat deformation temperature to prevent deformation, and must be able to handle signals recorded on the disk. Because there are so many of them, it is necessary to be able to easily perform precise processing. However, vinyl chloride resin has the above-mentioned properties in a well-balanced manner and is superior to other resins in this respect. This has the disadvantage that the fluidity of the resin becomes extremely poor. For this reason, molding processing at high temperatures is required, but at this time it is required to add a large amount of stabilizer to improve thermal stability. There is a risk that the original excellent physical properties may be lost, and problems such as sticking to the mold may occur during molding at high temperatures. The present inventors have developed the present invention as a result of focusing on the fact that vinyl chloride resin is a resin that has excellent properties as described above, and as a result of studying the advantageous method of utilizing this resin. Vinyl resin 40 to 94% by weight, (b) Melt viscosity at 200℃ of 50 to 100,000 centipoise or 10% by weight toluene solution at 20℃
A low molecular weight product consisting of one or more monomers selected from aromatic vinyl compounds, acrylic acid or methacrylic acid, and their esters, with a viscosity of 10 centipoise or less and a softening point of 70°C or more. The present invention relates to a vinyl chloride resin composition for a capacitive video disc, comprising: 1 to 30% by weight of a polymer; and (c) 5 to 30% by weight of carbon black. The present invention will be explained in detail below. The vinyl chloride resin (a) which is the main component of the composition of the present invention may be either a vinyl chloride homopolymer or a copolymer mainly composed of vinyl chloride, and the comonomer used in this copolymer is vinyl acetate. , vinyl esters such as vinyl propionate, olefins such as ethylene and propylene, and vinyl ethers such as lauryl vinyl ether, as well as styrene, acrylonitrile, maleic anhydride, acrylic acid or methacrylic acid, or esters thereof. The amount of these comonomers used should be kept to a small amount that does not significantly impair the inherent properties of the vinyl chloride resin, and it is desirable that the main component, vinyl chloride, be at least 70% by weight (particularly 80% by weight). . Next, component (b) is a low molecular weight polymer consisting of a monomer selected from aromatic vinyl compounds, acrylic acid or methacrylic acid, and their esters, and examples of this aromatic vinyl compound include styrene, α-methylstyrene, etc. Examples of acrylic acid or methacrylic acid or their esters include acrylic acid and its acrylic acid derivatives having 4 to 12 carbon atoms such as methyl, ethyl, and 2-ethylhexyl esters, and methacrylic acid and its methyl, butyl, and glycidyl esters. Examples include methacrylic acid derivatives having 5 to 12 carbon atoms. When a low-molecular-weight polymer obtained by polymerizing one or more of these monomers as a main ingredient is blended into a vinyl chloride resin, even if a relatively large amount of carbon black is mixed, the resin composition will deteriorate. Fluidity (molding processability) does not deteriorate significantly, and
Excellent results were obtained in wear resistance, heat resistance (heat distortion temperature), and precision machinability. In order to achieve this excellent effect,
The polymer must have a melt viscosity of 50 to 100,000 centipoise at 200°C, or a viscosity of 10% by weight toluene solution at 20°C of 10 centipoise or less, and a softening point of 70°C or higher. Needed. This low molecular weight polymer has a melt viscosity of 50 centipoise or less at 200°C or a softening point of 70 centipoise or less.
℃ or higher, the vinyl chloride resin composition blended with it will have poor flexibility temperature and mechanical strength, and if the melt viscosity is 100,000 centipoise or higher or a 10% by weight toluene solution. If the viscosity at 20°C is 10 centipoise or more, the vinyl chloride resin composition blended with the same shows almost no improvement in fluidity (molding processability), and in any case, the present invention No effect is achieved. In addition, when using a polymer mainly composed of an aromatic vinyl compound as this component (b), rather than a polymer consisting of an aromatic vinyl compound alone,
A copolymer of an aromatic vinyl compound and acrylic acid or methacrylic acid or an ester thereof (particularly a copolymer in which the aromatic vinyl compound has a mole number of 80 or less) is preferable. The desirable viscosity range and desirable composition of a 10% by weight toluene solution of this product at 20°C are illustrated in the attached drawing. The shaded area in the drawing is the desired viscosity range, 2
The area where the two diagonal lines intersect indicates a particularly desirable area. Furthermore, the plotted symbols A to J represent the respective (b) components A to J used in the examples at their corresponding positions, and according to this, C, D, G, and E of A to J are used in the examples. It turns out that it is a very desirable ingredient. A desirable blending ratio of component (b) is such that the amount of component (b) in the composition is 1 to 30% by weight, particularly 2 to 20% by weight. If this amount is less than 1% by weight, the effect of improving fluidity (molding processability) will be small, while if it is more than 30% by weight, the original physical properties (mechanical strength, etc.) of vinyl chloride resin will be diminished. It is disadvantageous. Carbon black as component (c) is blended to impart conductivity to the molded product (video disc), and it is desirable to use fine particles that have a large effect of imparting conductivity.
(Cities Services), Vulcan XC-72 (Cabot), Ketsuchen Black EC (AKZO)
Preferred are those commercially available under the trade names of . Although the appropriate amount of component (c) varies depending on the type, it is desirable that the amount of component (c) in the composition is in the range of 5 to 30% by weight. If the amount is less than 5% by weight, the imparting of conductivity is insufficient, and if the amount is more than 30% by weight, the molding processability will be poor and the physical properties (mechanical strength, etc.) of the molded product will be inferior, which is disadvantageous. The vinyl chloride resin composition for capacitive video discs of the present invention can be obtained by blending the above-mentioned components (a) to (c). Modifying agents for improving the impact strength of, for example, acrylonitrile-butane diene-styrene copolymer, methyl methacrylate-styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, chlorinated polyethylene,
Ethylene-vinyl acetate-vinyl chloride copolymer or the like may be added in an amount of approximately 1 to 15% by weight, which has the advantage of making the video disc hard to break and easy to handle. . It should be noted that care must be taken when using such a modifier, since if the amount added is too large, the resulting video disc may have a poor softening temperature. In preparing the composition, stabilizers,
Plasticizers, lubricants, fillers, etc. are appropriately blended. Stabilizers include tribasic lead sulfate, lead stearate, dibasic lead stearate, calcium stearate, zinc octanoate, cadmium stearate, barium laurate, dimethyltin dilaurate, dibutyltin malate, dioctyltin mercaptide, etc. Metal stabilizers, organic phosphorus stabilizers such as triphenyl phosphite, epoxy resins, epoxidized soybean oil, epoxidized polybutadiene, organic stabilizers such as 2-phenylindole, and oxidation of t-butylhydroxytoluene, etc. Stearic acid, cetanol, polyethylene wax, etc. are used as lubricants, and calcium carbonate, white carbon, etc. are used as fillers.
Examples include calcium silicate and the like. Note that any plasticizer that has been conventionally used for vinyl chloride resins can be used. Next, specific examples (Experiments No. 1 to No. 19) will be given, in which (a) the vinyl chloride resin and (b) the low molecular weight polymer were used as shown below. (A) Vinyl chloride resin (A) -: Polyvinyl chloride, degree of polymerization 700 (A) -: Polyvinyl chloride, degree of polymerization 500 (A) -: Polyvinyl chloride, degree of polymerization 350 (A) -: Vinyl chloride -Propylene copolymer (propylene 5% by weight), degree of polymerization 520 (A)-: Vinyl chloride-ethylene copolymer (5% by weight ethylene), degree of polymerization 550 (A)-: Vinyl chloride-vinyl acetate copolymer (vinyl acetate 18% by weight), degree of polymerization 450 *Measurement of the degree of polymerization above is based on JIS K6721. (b) Low molecular weight polymer As shown in Table 1.

【table】

[Table] Experiment No. 1 to No. 15 (a) Vinyl chloride resin and (b) low molecular weight polymer were mixed in the amounts shown in Table 2, and to this was added 4.0 g of dibutyltin malate and 0.5 g of stearic acid. 20g of Ketchen Black EC was added thereto and kneaded for 15 minutes using a heating roll (160°C). Regarding the molding material thus obtained, the flow temperature (°C) was measured, and the impact strength (sharpy kg/cm), flexibility temperature (°C), and tensile strength (Kg/cm ² ) of the molded product (test piece) were measured. , the results shown in Table 2 were obtained.

【table】

【table】

[Table] *4 Tensile strength)
Experiment No. 16-19 Vinyl chloride resin (g) ...Table 3 Low molecular weight polymer (g) ...Table 3 Rubber modifier (g) ...Table 3 (types are shown below) Dibutyl Tin malate...4.0g Stearic acid...0.5g Kettchen Black EC...20g Kneading and molding (preparation of test pieces) were performed in the same manner as above except that the above compound was used, and various physical properties were measured. The results were as shown in Table 3. Rubber modifier: EVA-VC: Levaprene 45/5 manufactured by Bayer
0 CPE: Chlorinated polyethylene elasthrene 355A manufactured by Showa Denko K.K.

【table】 [Brief explanation of drawings]

The drawing shows a "shaded area" which is a desirable region for the "low molecular weight polymer" component (b) of the present invention, and the region where two diagonal lines intersect shows a particularly desirable region. The symbols A to J in the drawings refer to each symbol used in the examples.
(b) Components A to J are shown in their corresponding positions. Vertical axis: aromatic vinyl compound (mol%), horizontal axis: 10% by weight toluene solution of low molecular weight polymer
Viscosity (centipoise) at 20℃.

Claims (1)

[Scope of Claims] 1 (a) 40 to 94% by weight of a vinyl chloride resin, (b) a melt viscosity of 50 to 100,000 centipoise at 200°C, or 20% by weight of a 10% by weight toluene solution.
The viscosity at °C is 10 centipoise or less,
and 1 to 30% by weight of a low molecular weight polymer consisting of one or more monomers selected from aromatic vinyl compounds, acrylic acid or methacrylic acid, and their esters, and having a softening point of 70°C or higher, and (c) A vinyl chloride resin composition for a capacitive video disk, comprising 5 to 30% by weight of carbon black.