Non-transparent microvoided axially stretched film, production process therefor and process for obtaining a transparent pattern therewith

Abstract

A film consisting essentially of a continuous phase linear polyester matrix having dispersed therein a non-crosslinked random SAN-polymer and dispersed or dissolved therein at least one ingredient from the group of ingredients consisting of inorganic opacifying pigments, whitening agents, colorants, UV-absorbers, light stabilizers, antioxidants and flame retardants, wherein the film is white, microvoided, non-transparent and axially stretched; the linear polyester matrix has monomer units consisting essentially of at least one aromatic dicarboxylic acid, at least one aliphatic diol and optionally at least one aliphatic dicarboxylic acid; and the weight ratio of the linear polyester to the non-crosslinked SAN-polymer is in the range of 2.0:1 to 19.0:1, wherein one of the said at least one aliphatic dimethylene monomer units is selected from the group consisting of neopentylene and 1,4-cyclohexanedimethylene in a concentration of 30 mole % or less of all aliphatic dimethylene monomer units; the use of the film as or in synthetic paper; an image recording element comprising the film; a process for the preparing of the non-transparent microvoided axially stretched film; and a process for obtaining a transparent pattern therewith.

1 . A film consisting essentially of a continuous phase linear polyester matrix having dispersed therein a non-crosslinked random SAN-polymer and dispersed or dissolved therein at least one ingredient from the group of ingredients consisting of inorganic opacifying pigments, whitening agents, colorants, UV-absorbers, light stabilizers, antioxidants and flame retardants, wherein said film is white, microvoided, non-transparent and axially stretched; said linear polyester matrix has monomer units consisting essentially of at least one aromatic dicarboxylic acid, at least one aliphatic diol and optionally at least one aliphatic dicarboxylic acid; the weight ratio of said linear polyester to said non-crosslinked SAN-polymer is in the range of 2.0:1 to 19.0:1; and one of the said at least one aliphatic dimethylene monomer units is selected from the group consisting of neopentylene and 1,4-cyclohexanedimethylene in a concentration of 30 mole % or less of all aliphatic dimethylene monomer units. 
     
     
         2 . The film according to  claim 1 , wherein said film is a biaxially stretched film. 
     
     
         3 . The film according to  claim 1 , wherein the concentration of inorganic opacifying pigment is ≧0.1% by weight. 
     
     
         4 . The film according to  claim 1 , wherein one of the said at least one aliphatic dimethylene monomer units is selected from the group consisting of neopentylene and 1,4-cyclohexanedimethylene in a concentration of 20 mole % or less of all aliphatic dimethylene monomer units, 
     
     
         5 . The film according to  claim 1 , wherein the concentration of AN-monomer units in said SAN-polymer is 15 to 35% by weight. 
     
     
         6 . The film according to  claim 1 , wherein said weight ratio of said linear polyester to said non-crosslinked SAN-polymer is in the range 2.7:1 to 9.0:1. 
     
     
         7 . A process for using in synthetic paper a film consisting essentially of a continuous phase linear polyester matrix having dispersed therein a non-crosslinked random SAN-polymer and dispersed or dissolved therein at least one ingredient from the group of ingredients consisting of inorganic opacifying pigments, whitening agents, colorants, UV-absorbers, light stabilizers, antioxidants and flame retardants, wherein said film is white, microvoided, non-transparent and axially stretched; said linear polyester matrix has monomer units consisting essentially of at least one aromatic dicarboxylic acid, at least one aliphatic diol and optionally at least one aliphatic dicarboxylic acid; the weight ratio of said linear polyester to said non-crosslinked SAN-polymer is in the range of 2.0:1 to 19.0:1; and one of the said at least one aliphatic dimethylene monomer units is selected from the group consisting of neopentylene and 1,4-cyclohexanedimethylene in a concentration of 30 mole % or less of all aliphatic dimethylene monomer units. 
     
     
         8 . An image recording element comprising a film consisting essentially of a continuous phase linear polyester matrix having dispersed therein a non-crosslinked random SAN-polymer and dispersed or dissolved therein at least one ingredient from the group of ingredients consisting of inorganic opacifying pigments, whitening agents, colorants, UV-absorbers, light stabilizers, antioxidants and flame retardants, wherein said film is white, microvoided, non-transparent and axially stretched; said linear polyester matrix has monomer units consisting essentially of at least one aromatic dicarboxylic acid, at least one aliphatic diol and optionally at least one aliphatic dicarboxylic acid; the weight ratio of said linear polyester to said non-crosslinked SAN-polymer is in the range of 2.0:1 to 19.0:1; and one of the said at least one aliphatic dimethylene monomer units is selected from the group consisting of neopentylene and 1,4-cyclohexanedimethylene in a concentration of 30 mole % or less of all aliphatic dimethylene monomer units. 
     
     
         9 . The image recording element according to  claim 8 , wherein said image is a non-photographic image. 
     
     
         10 . The image recording element according to  claim 8 , wherein said film is provided on at least one side with an overprintable layer. 
     
     
         11 . The image recording element according to  claim 8 , wherein said film is provided on at least one side with a non-transparent transparentizable overprintable layer. 
     
     
         12 . The image recording element according to  claim 8 , wherein said film is provided on at least one side with an ink-jet receiving layer. 
     
     
         13 . The image recording element according to  claim 8 , wherein said film is provided on at least one side with an imaging layer. 
     
     
         14 . The image recording element according to  claim 8 , wherein said film is provided with a writable layer. 
     
     
         15 . A process for preparing a non-transparent microvoided axially stretched film comprising the steps of: i) mixing at least one linear polyester having monomer components consisting essentially of at least one aromatic dicarboxylic acid, at least one aliphatic diol and optionally at least one aliphatic dicarboxylic acid, a non-crosslinked random SAN-polymer and at least one ingredient from the group of ingredients consisting of inorganic opacifying pigments, whitening agents, colorants, UV-absorbers, light stabilizers, antioxidants and flame retardants in a kneader or an extruder to produce a mixture comprising said non-crosslinked random SAN-polymer in a polyester matrix, ii) forming the mixture produced in step i) in a thick film followed by quenching; and iii) stretching said thick film at a stretching tension of >2.5 N/mm 2  at a temperature between the glass transition temperature of said SAN-polymer and the glass transition temperature of said linear polyester to at least twice the initial length, wherein the weight ratio of said polyester matrix to said non-crosslinked random SAN-polymer is in the range of 2.0:1 to 19.0:1 and wherein one of the said at least one aliphatic dimethylene monomer units is selected from the group consisting of neopentylene and 1,4-cyclohexanedimethylene in a concentration of 30 mole % or less of all aliphatic dimethylene monomer units. 
     
     
         16 . The process according to  claim 15 , wherein said process comprises a further step, step (iv) in which said film is subjected to a further stretching process at an angle substantially 90° to the first stretching process to at least twice the initial length at a stretching tension of >2.5 N/mm 2  and a temperature between the glass transition temperature of said SAN-polymer and the glass transition temperature of the linear polyester 
     
     
         17 . The process according to  claim 15 , wherein step iv) is performed at a film temperature at or below 120° C. 
     
     
         18 . The process according to  claim 15 , wherein steps iii) and iv) are performed simultaneously. 
     
     
         19 . The process according to  claim 15 , wherein at least one of said at least one aromatic dicarboxylic acid monomer units is isophthalic acid and said isophthalic acid is present in said polyester matrix in a concentration of 15 mole % or less of all the dicarboxylic acid monomer units in said linear polyester matrix. 
     
     
         20 . A process for obtaining a transparent pattern comprising the step of: image-wise application of heat optionally supplemented by the application of pressure to a film consisting essentially of a continuous phase linear polyester matrix having dispersed therein a non-crosslinked random SAN-polymer and dispersed or dissolved therein at least one ingredient from the group of ingredients consisting of inorganic opacifying pigments, whitening agents, colorants, UV-absorbers, light stabilizers, antioxidants and flame retardants, wherein said film is white, microvoided, non-transparent and axially stretched; said linear polyester matrix has monomer units consisting essentially of at least one aromatic dicarboxylic acid, at least one aliphatic diol and optionally at least one aliphatic dicarboxylic acid; the weight ratio of said linear polyester to said non-crosslinked SAN-polymer is in the range of 2.0:1 to 19.0:1; and one of the said at least one aliphatic dimethylene monomer units is selected from the group consisting of neopentylene and 1,4-cyclohexanedimethylene in a concentration of 30 mole % or less of all aliphatic dimethylene monomer units.