Process for preparing surface-upgraded molded articles using a low thermal inertia mold
AssigneeCentro Sviluppo Settori Impiego S.r.l.
InventorsAntonio Addeo, Vincenzo Cocca, Ivano Tommasi
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Abstract
Blow molding and thermoforming processes in which a mold system having low thermal inertia mold-halves provided with heating and cooling systems is utilized for producing plastic articles coated with surface-upgrading films of high melting polymers or polymers exhibiting a high scratch resistance to improve mechanical characteristics of the molded article. The films may be positioned, before the mold is closed, close to the low thermal inertia mold-halves. Rapid heating and rapid cooling of the mold-halves in contact with the surface-upgraded films permit strength adhesion of the upgrading material to the surface of the molded article.
Claims8
A blow molding process for making articles that are at least partially covered by a surface-upgrading layer, the process comprising:
- (a) positioning a surface-upgrading film close to an internal surface of at least one of two mold-halves of a blow molding mold while the mold is open, the at least one of two mold-halves comprising means for heating and cooling at least part of said internal surface;
- (b) extruding a tube made of a first thermoplastic polymer between the two open mold-halves, closing the mold and inflating the tube with air to blow mold the tube against the surface-upgrading film;
- (c) rapidly heating at least part of said internal surface to a temperature sufficient to melt the surface-upgrading film to adhere the surface-upgrading film to the inflated tube;
- (d) rapidly cooling at least part of said internal surface to a temperature close to that of the inflated tube;
- and
- (e) stopping the inflation and extracting the finished article;
- wherein, the surface-upgrading film is a second thermoplastic polymer having a melting point which is higher than the melting point of the first thermoplastic polymer.
A thermoforming process for making articles that are at least partially covered by a surface-upgrading layer, the process comprising:
- (a) positioning a surface-upgrading film close to an internal surface of at least one of two mold-halves of a thermoforming mold while the mold is open, the at least one of two mold-halves comprising means for heating and cooling at least part of said internal surface;
- (b) heating a sheet or foil made of a first thermoplastic polymer to the softening temperature of the polymer;
- (c) thermoforming the sheet or foil and coupling it to the surface-upgrading film;
- (d) rapidly heating at least part of said internal surface to a temperature sufficient to melt the surface-upgrading film so that the surface-upgrading film adheres to the thermoformed sheet;
- (e) rapidly cooling at least part of said internal surface to a temperature close to that of the thermoformed sheet;
- and
- (f) extracting the finished article;
- wherein the surface-upgrading film comprises a second thermoplastic polymer having a melting point which is higher than the softening point of the first thermoplastic polymer.
Dependencies are inferred from the claim text.