Process for production of biaxially oriented films based on crystallizable thermoplastics, using recycled material whose molecular weight has been increased by condensation processes
First Claim
1. A process for production of a biaxially oriented film which comprises extruding or coextruding a composition comprising (i) at least one crystallizable thermoplastic as main constituent (ii) at least 500 ppm, based on the weight of the thermoplastic, of a pigment, and (iii) a total of from 60 to 100% by weight, based on the weight of the film, of a mixture of recycled material formed entirely from said film,wherein the molecular weight of at least 20% by weight, based on the weight of the film, of recycled material formed entirely from said film within said recycle mixture has been increased by condensation processes prior to said extruding or coextruding step, andsaid film exhibits a modulus of elasticity in the transverse direction of greater than or equal to 5100 N/mm2,wherein the standard viscosity SV (DCA) of the recycled material has been increased by the condensation process by at least 100 up to the standard viscosity SV (DCA) of said crystallizable thermoplastic prior to said extrusion or coextrusion, andwherein the mixture of recycled material includes from 10 to 40% by weight, based on the weight of the film, of additional recycled material other than the recycled material whose molecular weight has been increased.
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Abstract
A process is described for production of a biaxially oriented film which comprises at one crystallizable thermoplastic as main constituent and comprises at least 500 ppm, based on the weight of thermoplastic, of a pigment. The production process uses at least 20% by weight, based on the weight of the film, of recycled material of the same type whose molecular weight has been increased by condensation processes.
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Citations
14 Claims
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1. A process for production of a biaxially oriented film which comprises extruding or coextruding a composition comprising (i) at least one crystallizable thermoplastic as main constituent (ii) at least 500 ppm, based on the weight of the thermoplastic, of a pigment, and (iii) a total of from 60 to 100% by weight, based on the weight of the film, of a mixture of recycled material formed entirely from said film,
wherein the molecular weight of at least 20% by weight, based on the weight of the film, of recycled material formed entirely from said film within said recycle mixture has been increased by condensation processes prior to said extruding or coextruding step, and said film exhibits a modulus of elasticity in the transverse direction of greater than or equal to 5100 N/mm2, wherein the standard viscosity SV (DCA) of the recycled material has been increased by the condensation process by at least 100 up to the standard viscosity SV (DCA) of said crystallizable thermoplastic prior to said extrusion or coextrusion, and wherein the mixture of recycled material includes from 10 to 40% by weight, based on the weight of the film, of additional recycled material other than the recycled material whose molecular weight has been increased.
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12. A process for producing biaxially oriented film having a thickness ranging from 4 to 300 microns comprising extruding or coextruding a composition comprising (i) at least one crystallizable thermoplastic and (ii) at least 500 ppm, based on the weight of the thermoplastic, of a pigment,
wherein said film further comprises from 50 to 100% by weight, based on the weight of the film, of a mixture of recycled material formed entirely from said film, the molecular weight of from 20% to 80% by weight, based on the weight of the film, of said recycled material within said recycle mixture has been increased by condensation processes prior to said extruding or coextruding step, the mixture of recycled material further includes from 10 to 40% by weight, based on the weight of the film, of additional recycled material other than the recycled material whose molecular weight has been increased, said film exhibiting a modulus of elasticity in the transverse direction of greater than or equal to 4200 N/mm2, and the standard viscosity SV (DCA) of the recycled material has been increased by the condensation process by at least 100 up to the standard viscosity SV (DCA) of said crystallizable thermoplastic prior to said extrusion or coextrusion.
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14. A process for production of a biaxially oriented film which comprises extruding or coextruding a composition comprising at least one crystallizable thermoplastic as main constituent;
- at least 500 ppm, based on the weight of the thermoplastic, of a pigment; and
recycled material,said film comprising from 50 to 100% by weight, based on the weight of the film, of a mixture of (i) recycled material formed entirely from said film and (ii) recycled material formed entirely from said film whose molecular weight has been increased by condensation processes prior to said extruding or coextruding step, wherein the film has a thickness of less than 4 microns and comprises from 30% to 40% by weight, based on the weight of the film, of said recycled material formed entirely from said film whose molecular weight has been increased or the film has a thickness of greater than 300 microns and comprises from 20% to 70% by weight, based on the weight of the film, of said recycled material formed entirely from said film whose molecular weight has been increased and from 10 to 40% by weight, based on the weight of the film, of additional recycled material other than the recycled material whose molecular weight has been increased and the standard viscosity SV (DCA) of the recycled material has been increased by the condensation process by at least 100 up to the standard viscosity SV (DCA) of said crystallizable thermoplastic prior to said extrusion or coextrusion.
- at least 500 ppm, based on the weight of the thermoplastic, of a pigment; and
Specification