Manufacturing process of a product based on cellulose acetate with blended colour, and product, such as spectacles, obtained by such process

A manufacturing process of a semi-finished product of thermoplastic material, such as cellulose acetate, for obtaining products with aesthetic patterns which can be perceived in semi-transparency also in depth, comprising the mixing and the consolidation, through pressure and heat, of base particulate members having different dominating colouring, comprising the steps of

• producing at least two initial elements of a thermoplastic material with even aesthetic patterns which are different each other and characterised in that furthermore
• said even aesthetic patterns of the at least two initial elements (L1-Ln;
• S1′-Sn′) of thermoplastic material have a different concentration of the dominating colouring (Cn> . . . >C2>C1≧0), at least the dominating colouring being of a bleeding type in the specific thermoplastic material,
• said two initial elements (L1-Ln;
• S1′-Sn′) are shaped into strips or loaves (S1-Sn;
• S1′-Sn′) of a submultiple width, not below ⅕, preferably not below ⅓, of a characteristic dimension of a finished product to be obtained,
• at least two of said strips or loaves (S1-Sn;
• S1′-Sn′) having different concentration of the dominating colouring are then inserted into a workform, arranging them side by side according to a side-by-side arrangement direction, defining at least one layer of base module having a width of the order of magnitude of a characteristic dimension of the finished product to be obtained,
• said at least one layer of base module in the workform then undergoing pressure and heat to allow the melting and consolidation of the thermoplastic material in a single body, at the same time causing the migration of the dominating colouring at least from the strips or loaves (S1-Sn;
• S1′-Sn′) with the greater concentration of the dominating colouring towards those with a lesser concentration of the dominating colouring, thus determining a blurred colour hue in the boundary areas between the different strips or loaves (S1-Sn;
• S1′-Sn′), and
• finally cutting said single body of thermoplastic material into terminal sheets according to a plane parallel to said direction of side-by-side arrangement between said strips or loaves (S1-Sn;
• S1′-Sn′).