Method for the continuous formation of biaxially oriented thermoplastic materials and forming articles therefrom by intermittent forming means interfaced therewith

The method of extruding and orienting a web of thermoplastic material in a continuous mode and subsequently forming molded products therefrom in an intermittent mode without interruption of said continuous mode, comprising:

• extruding a web of thermoplastic material and presenting it continuously to an orientation means at an optimum orientation temperature;
• stretch orienting the web to a desired degree in the transverse and longitudinal dimensions thereof whole said web is in continuous longitudinal motion;
• continuously interfacing and juxtaposing said oriented web with an undulating and rotating peripheral interfacing surface in a dimensionally stable engagement therewith to preserve the integrity of the orientation therein;
• intermittently extracting predetermined incremental lengths of the oriented web from the interfacing surface in synchronism with the undulations of the latter to establish an intermittent feed mode of said web downstream of said interfacing surface without disturbing the continuous mode upstream thereof;
• interfacing the said incremental lengths with a forming means;
• and
• intermittently forming products in said incremental lengths of oriented web with said forming means while preserving the integrity of orientation therein, wherein the stress placed in the thermoplastic material by said biaxial orientation is substantially maintained from the initiation of said orientation to the forming of the products therein.

The method of forming products of biaxially oriented thermoplastic material comprising:

• continuously extruding a web of thermoplastic material;
• biaxially stretching said web in a continuous manner to effect biaxial orientation therein and dimension said web for subsequent forming;
• substantially immediately transferring said web into conformal and dimensionally stable engagement with an undulating rotating peripheral surface to preclude loss of orientation;
• maintaining a stable temperature in said web on said undulating surface;
• transferring said web from said undulating surface onto a downstream transfer means while maintaining the dimensional integrity of said web;
• synchronizing the transfer means with the undulations of said peripheral surface to intermittently advance lengths of the web on said transfer means while continuously feeding the web onto said undulating surface;
• and
• forming products in said intermittently advanced lengths of said web on said transfer means substantially immediately upon the completion of each advance to enhance thermal stability therein, wherein the stress placed in the thermoplastic material by said biaxial orientation is substantially maintained from the initiation of said orientation to the forming of the products therein.

The method of extruding and orienting a web of thermoplastic material in a continuous mode and subsequently forming molded products therefrom in an intermittent mode without interruption of said continuous mode, comprising:

• extruding a web of thermoplasticmaterial and presenting it continuously to an orientation means at an optimum orientation temperature;
• stretch orienting the web to a desired degree in the transverse and longitudinal dimensions thereof while said web is in continuous longitudinal motion;
• continuously interfacing and juxtaposing said oriented web with an undulating and rotating peripheral interfacing surface in a dimensionally and thermally stable engagement therewith to preserve the integrity of the orientation and the temperature therein;
• intermittently extracting predetermined incremental lengths of the oriented web from the interfacing surface in synchronism with the undulations of the latter to establish an intermittent feed mode of said web downstream of said interfacing surface without disturbing the continuous mode upstream thereof;
• interfacing the said incremental lengths with a forming means;
• and
• intermittently forming products in said incremental lengths of oriented web with said forming means substantially immediately upon receipt thereof to enhance the thermal stability of said web while preserving the integrity of orientation therein, wherein the stress placed in the thermoplastic material by said biaxial orientation is substantially maintained from the initiation of said orientation to the forming of the products therein.