DE526497C - Process for the production of plastic masses - Google Patents

Description

Process for the production of plastic masses It has been found that the saponification products obtainable by saponification of polyvinyl esters, which are soluble or swellable in almost unlimited amounts in water, this solubility property easily lose if subjected to certain treatments. It is enough u. a. heating to a higher temperature, e.g. B. water bath temperature to the product insoluble in cold water. This process is accelerated by certain Additions, especially of those substances that have tannin properties or protein able to precipitate, such as tannin, formaldehyde. This addition is generally required but not, so that this method differs from other methods, e.g. B. the hardening process of glue, gelatin, etc. with formaldehyde, advantageously differentiates. It succeeds on this way, artificial masses, such as everyday objects, gramophone records, film tapes, prepare by adding an aqueous solution of the saponification product obtained evaporated under the necessary measures and during the evaporation or on At the end of the same, the obtained, still liquid mass gives the required shape.

Example 100 parts by weight of a 15% solution of low viscosity Polyvinyl alcohol in water are evaporated in vacuo with thorough stirring. The residue, freed from water, is a horn-like mass, which at Can be pressed into molds at elevated temperature. Will it be in these forms at sthaiobis2oAtm. Print 1/2 hour at 15o to 16o 'or longer at low temperature kept, after cooling one gets a homogeneous, translucent, thin one Layers of clear plate. You can use the polyvinyl alcohol without first Press to dissolve and evaporate, but then have to use considerably higher pressure, to get homogeneous masses.

Example 2 100 parts by weight of a 50% aqueous solution of a Highly viscous polyvinyl alcohol is mixed with 5 parts by weight of formaldehyde and the solution is heated to the boil. After a short time, the mass begins to become tough and finally solidifies into something that is insoluble in water, coagulated, protein-like Gel. If this is dried in a vacuum after being crushed, the mass can be similar like the product obtained in the previous example by pressing into desired Bring shapes.

Example 3 30 parts by weight of polyvinyl alcohol are mixed with 10 parts by weight Tannin as fine as possible mixed that. Then mix in a die pressed between two iron plates at = 20 to 130 'for about 1/2 hour. -To Removal of the pressure and cooling gives a film or one depending on the one used Amount of more or less thick plate, which is characterized by great elasticity and resistance against mechanical stress. If you don't add tannin to the mass, so it is necessary to heat something longer or higher in order to become insoluble Product to arrive.

Claims (1)

PATENT CLAIM: Process for production in water and organic Solvents of insoluble or sparingly soluble plastic masses from water-soluble, by saponification of. Polyvinyl alcohols obtained from polyvinyl esters, characterized in that that the polyvinyl alcohols by heating, optionally to temperatures of 100 ° and above, or by protein-precipitating or tanning agents, or by both subject to post-treatment.