FI62120B - PRESSMASSA PAO BASIS AV SAMPOLYMER AV VINYL CHLORIDE AND VINYL ACETATE SPECIFIC FOR GRAMMOPHONE - Google Patents

Description

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National Board of Patents and Registration · Ntttiv «k.ip« on |. kteMtate. lnc. _

Patent · och registarttyrclMn An »6k» n utlagd och utUkrlfwn published 30.07 - Ö2 (32) (33) (31) Pyydetty «tuolkoiii — Begird prtorltet 10.05 .7 ^

Sweden-Sverige (SE) 7 ^ 06251- ^ (71) AB Nynäs-Petroleum, Regeringsgatan 109, S-lll 39 Stockholm,

Sweden-Sverige (SE) (72) Bert Karl Gustaf Lundgren, Nynashamn, Sweden-Sverige (SE) (7M Berggren Oy Ab (5 ^) Compression mass based on copolymers of vinyl chloride and vinyl acetate, in particular for sound discs - Press pulp on a base basis of vinyl chlorides This invention relates to a compression mass based on copolymers of vinyl chloride, and more particularly to this invention in its compression state for sound discs.

Conventional compression masses for records are mostly formed from copolymers of vinyl chloride, in addition to which smaller amounts of additives such as one or more lubricants, polyvinyl chloride (PVC) stabilizers and dyes, usually carbon black. Together with vinyl chloride, the copolymer-containing monomer used is one which can act as an internal plasticizer, usually vinyl acetate. This copolymer may be present in the copolymer in amounts of about 5 to 10% by weight, usually 7 to 10% by weight. The lubricant is, for example, metal stearates and / or low molecular weight waxes in amounts of 0.1 to 0.8 by weight of k. Examples of PVC thermal stabilizers are metal fatty acid salts such as barium-cadmium-zinc salts of fatty acid, organometallic products such as organotin compounds and inorganic salts such as lead sulphate. The compression mass may contain these 0.2-5 weight-k. Carbon black is in the compression mass to give the records the black color that the audience is used to in the records. The amount of carbon black 2,62120 is usually 0.3 to 2 by weight.

It has been found that certain mineral oil products can be used as a copolymer additive while providing better properties in the compression mass in terms of its processability and better quality in the sound reproduction of sound discs made from the mass. Due to their dark color, these mineral oil products can simultaneously fully or (in small additions) partially fulfill the function that carbon black fulfills in conventional sound recording presses. In contrast to carbon black, the additive used according to the invention is not present in partial form in the finished disc, which, as irregularities in the grooves of the sound disc, could cause a certain distortion in the sound. The additive used according to the invention can also, due to its low viscosity at elevated temperature, make it possible to reduce the concentration of lubricants used in conventional compression masses.

The above-mentioned advantages are obtained according to the invention with a compression mass based on copolymers of vinyl chloride and acetate, characterized in that it contains from 5 to 80% by weight, preferably from 35 to 65% by weight of oxidized mineral oil distillates or solvent extracts of oxidized mineral oil distillates. value of more than 0.85, preferably more than 0.90, and having a boiling point of more than 350 ° C, preferably more than M00 ° C at 760 mm Hg.

The oxidized mineral oil distillates used in the press compositions according to the invention can be obtained in such a way that a mineral oil distillate having an aromatically bound carbon content of more than 0.85, preferably more than 0.90, and preferably in the temperature range of 200-550 ° C, preferably 275 -500 ° C boiling fraction, is oxidized by air blowing, after which the oxidized distillate is distilled to recover a fraction having a boiling point above 350 ° C, preferably above 400 ° C. If desired, the preparation can also take place in several steps than those mentioned above, alternately by oxidation and distillation. The above-mentioned oxidized solvent extracts of mineral oil distillates are obtained in a similar manner by oxidizing a solvent extract obtained from a mineral oil distillate having an aromatically bound carbon content of more than 0.85, preferably more than 0.90, after which the oxidized extract is distilled to recover the desired fraction. A particularly preferred form of oxidized distillate or extract, 62120 The product form is that obtained by jet cooling the fraction recovered for use in the compression mass according to the invention. The VGC value (VGC = Viscosity Gravity Constant) is a standard measure of the aromatic content of mineral oil products and is determined according to ASTM D 2140.

The compression masses according to the invention are prepared, for example, by mixing a conventional compression mass with an oxidized distillate or extract in a controlled ratio to obtain the intended concentrations of oxidized distillate or extract. Conventional sound recording presses tend to mix carbon black in a separate final step * which is carried out in a certain state due to the heavy pollution of the environment brought about by the treatment of carbon black. Due to the dark color of the oxidized distillate and extract used according to the invention, these can fulfill the function of carbon black, so that the carbon-black mixing step can be eliminated at concentrations of about 40% or more of the oxidized distillate and extract without any significant lightening of the plate color. In the spray-cooled form, the oxidized distillate and the extract are not dusty and thus offer substantial advantages from an occupational hygiene point of view compared to carbon black.

However, the compression masses according to the invention can in principle be prepared by mixing the various ingredients in an arbitrary order. However, as mentioned above, the mixing of the carbon black in the present case preferably takes place at such a stage that the disadvantages in terms of fouling are kept to a minimum.

The relatively high concentrations (> 55%) of the distillate or extract according to the invention cause a slight increase in stiffness and brittleness in the sheets made from the compression mass. This effect can be counteracted by increasing the concentration of the internal plasticizer monomer in the copolymer.

In the compression masses according to the invention, in conventional compression masses based on copolymers of vinyl chloride and acetate, ordinary lubricants and thermal stabilizers as well as carbon black can be included in concentrations known from conventional compression masses, if desired. However, the concentrations of these ingredients can be substantially reduced as indicated above. According to this

Claims (1)

4 62120, the compression mass according to the invention may contain 0 to 0.5% by weight, preferably 0 to 0.2% by weight, of carbon black, and the amount of lubricant may vary between 0 and 0.5% by weight, preferably between 0.05 and 0% by weight. 2 by weight # based on the weight of the pulp. The content of the thermal stabilizer depends mainly only on the content of the copolymer of vinyl chloride and acetate and corresponds to about 0.2 to 5% by weight based on the weight of the co-polymer. The invention is described in more detail below by means of an exemplary embodiment. Example 50 parts by weight of a product obtained by oxidizing a solvent extract of a mineral oil distillate with a VGC value of 0.96 and then distilling and removing the fraction boiling above 370 ° C and spray-cooling this fraction were mixed with 50 parts by weight. with a conventional sound pressure compact with a copolymer of 98.5 wt.% vinyl chloride (R) din and vinyl acetate (from Corvik ICI, England), 0.3 wt.% calcium stearate plus paraffin wax (lubricant), 0.7 wt.%. barium cadmium stabilizer (thermal stabilizer), 0.5 wt.% carbon black. From the obtained compression mass, sheets were compressed in a conventional manner, it being found that at the same compression temperature, the compression time in compression could be reduced by about 15% compared to the compression time with conventional compression pulp without adding oxidized extract due to lower melt viscosity. The weight of the sheets made from the pressing mass according to the invention was about 15 # lower than the weight of the sheets made of the conventional pressing mass. In addition, a lower tendency to warp could be observed with the previous plates. Compression mass based on copolymers of vinyl chloride and acetate, in particular for sound discs, characterized in that it contains from 5 to 80% by weight, preferably from 35 to 65% by weight, of oxidized mineral oil distillates or oxidized solvent extracts of mineral oil distillates having an aromatic content equal to V before oxidation. more than 0.85 and preferably more than 0.90, and having a boiling point of more than 350 ° C, preferably more than 400 ° C, at 760 mm Hg.