BE413254A - - Google Patents

Description

       

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  Patent of Invention PROCESS FOR DISSOLVING COLD COPAL.



   In the manufacture of varnishes, by means of oopal gums, the gums are generally solubilized, either by fusion, or in an autoclave using mothballs, or finally by means of vacuum. hot and therefore are relatively complicated and expensive.



  Up to now, attempts have been made to dissolve oopal in the cold, but the results obtained are not sufficient industrially.



   A specific subject of the present invention is a process making it possible to dissolve the oopal in the cold, completely or almost completely, when it is in the form of dust resulting, for example, from the various handling operations to which the oopal in pieces is subjected.



   A solvent is used for this purpose consisting of the following substances: benzol, xylol and isobutyl alool. These bodies can be used singly or as a mixture and in proportions depending on the origin of the oopal.



   Preferably, a mixture established according to

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 the following proportions:
20% benzol 70% xylol
10% isobutyl alcohol.



    One liter of this mixture is enough to dissolve 600 grams of oopal dust.



   To achieve this dissolution, it suffices to introduce the copal in dust into the solvent, with moderate stirring, then allowed to settle until saturation. A deposit is formed (generally less than 10% which is removed by filtrate). or in any other way. A plasticizer is added to the varnish thus obtained with a view to making it more flexible: as plasticizer one will advantageously use venicebentin, olein or an equivalent substance. The varnish thus obtained can be applied at once.



   The proportions indicated are given only by way of example; they could vary more or less within certain limits without departing from the scope of the invention.



   On the other hand, one could, in accordance with the invention, replace the benzol and xylol by other equivalent products resulting from the distillation of coal tar, or by a carbon compound, such as carbon sulphide. oarbone and oarbone tetrachloride. Similarly, isobutyl alcohol could be replaced by another higher homologue of ethyl alcohol: propyl alcohols, amyl alcohols, eto. Benzilic alcohol could also be used.



   In order to obtain varnishes which are more economical or which meet a particular application, it is obviously possible to mix with the oopal varnish thus obtained other suitable materials, in particular resins or gums, inorganic or other pigments, etc.


    

Claims (1)

CLAIMS. I. Cold dissolving process of oopal to dust, characterized in that the oopal is subjected to the action of a solvent consisting of one of the following elements or of a mixture of these elements: benzol, xylol and aloool isobutyl. 3.Process according to revendioation I, characterized in that one uses a mixture consisting of 20% of benzol, 70% of xylol and 10% of isobutyl aloool, for one liter of solvent per 600 grams of dust of oopal, the mixture slightly stirred, is then decanted. 3.Prooédé according to claim I, oaraotérisé in that the benzol and xylol are replaced by one or more equivalent products resulting from the distillation of tar. 4.Procédé claimed in claim I, characterized in that the benzol and xylol are replaced by an oarbon compound, such as oarbone sulfide or tetrachloride, or a mixture thereof. 5.Process according to Claim I, characterized in that the isobutyl alcohol is replaced by one or more higher homologues of ethyl alcohol, or by benzolic alcohol. 6.Procédé claimed in claim I, characterized in that the product obtained is, after deoantation, treated with a suitable plasticizer, then used directly, after having been added or not with another material depending on the envisaged application.