MULTI-LAYER CARD AND FILM ASSEMBLY

Abstract

A multi-layer card comprising a polymeric inlay layer having a first surface and a second surface, further comprising a first multi-layer film which is disposed on the first surface of the polymeric inlay layer, and further comprising a first polymeric overlay layer which is disposed on said first multi-layer film, such that the layer order is polymeric inlay layer, first multi-layer film and first polymeric overlay layer, wherein said first multi-layer film comprises: (i) a polyester base layer (B) comprising a crystallisable polyester (P.sub.B), and further comprising titanium dioxide in an amount of from about 1 to about 30 wt % by total weight of the base layer; (ii) a first heat-sealable copolyester layer (A1) disposed on a first surface of said polyester base layer; and (iii) optionally a second heat-sealable copolyester layer (A2) disposed on a second surface of said polyester base layer, wherein the copolyester (CP.sub.A) of each of the first and optional second heat-sealable copolyester layers is independently selected from amorphous copolyesters (ACP.sub.A) derived from an aliphatic diol and a cycloaliphatic diol and at least one aromatic dicarboxylic acid, and/or the polyester base layer (B) further comprises a copolyester (CP.sub.B) in an amount of at least about 10% by weight based on the total weight of the base layer (B).

Claims

1. A multi-layer card comprising a polymeric inlay layer having a first surface and a second surface, further comprising a first multi-layer film which is disposed on the first surface of the polymeric inlay layer, and further comprising a first polymeric overlay layer which is disposed on said first multi-layer film, such that the layer order is polymeric inlay layer, first multi-layer film and first polymeric overlay layer, wherein said first multi-layer film comprises: (i) a polyester base layer (B) comprising a crystallisable polyester (P.sub.B), and further comprising titanium dioxide in an amount of from about 1 to about 30 wt % by total weight of the base layer; (ii) a first heat-sealable copolyester layer (A1) disposed on a first surface of said polyester base layer; and (iii) optionally a second heat-sealable copolyester layer (A2) disposed on a second surface of said polyester base layer, wherein the copolyester (CP.sub.A) of each of the first and optional second heat-sealable copolyester layers is independently selected from amorphous copolyesters (ACP.sub.A) derived from an aliphatic diol and a cycloaliphatic diol and at least one aromatic dicarboxylic acid, and/or the polyester base layer (B) further comprises a copolyester (CP.sub.B) in an amount of at least about 10% by weight based on the total weight of the base layer (B).

2. A multi-layer card according to claim 1 wherein said first multi-layer film comprises: (i) a polyester base layer (B) comprising a crystallisable polyester (P.sub.B), and further comprising titanium dioxide in an amount of from about 1 to about 30 wt % by total weight of the base layer; and (ii) a first heat-sealable copolyester layer (A1) disposed on a first surface of said polyester base layer; and (iii) optionally a second heat-sealable copolyester layer (A2) disposed on a second surface of said polyester base layer, wherein the copolyester (CP.sub.A) of each of the first and optional second heat-sealable copolyester layers is independently selected from amorphous copolyesters (ACP.sub.A) derived from an aliphatic diol and a cycloaliphatic diol and at least one aromatic dicarboxylic acid, preferably wherein the polyester base layer (B) further comprises a copolyester (CP.sub.B) in an amount of at least about 10% by weight based on the total weight of the base layer (B).

3. A multi-layer card according to claim 1 wherein said first multi-layer film comprises: (i) a polyester base layer (B) comprising a crystallisable polyester (P.sub.B), and further comprising titanium dioxide in an amount of from about 1 to about 30 wt % by total weight of the base layer; and (ii) a first heat-sealable copolyester layer (A1) disposed on a first surface of said polyester base layer; and (iii) optionally a second heat-sealable copolyester layer (A2) disposed on a second surface of said polyester base layer, wherein the polyester base layer (B) further comprises a copolyester (CP.sub.B) in an amount of at least about 10% by weight based on the total weight of the base layer (B).

4. A multi-layer card according to any of claims 1 to 3 wherein the copolyester (CP.sub.A) of the first and second heat-sealable layers (A1) and (A2) is independently selected from copolyesters containing only one aromatic dicarboxylic acid, one aliphatic glycol, and one cycloaliphatic glycol, and preferably from copolyesters derived from terephthalic acid, ethylene glycol and 1,4-cyclohexanedimethanol, preferably wherein the molar ratio of the cycloaliphatic diol to the aliphatic diol is in the range from 30:70 to 35:65.

5. A multi-layer card according to claim 3 wherein the copolyester (CP.sub.A) of each of the first and optional second heat-sealable layers (A1) and (A2) is selected from copolyesters (I-CP.sub.A) derived from repeating units consisting of a first aromatic dicarboxylic acid, a second aromatic dicarboxylic acid and an aliphatic glycol,

6. A multi-layer card comprising a polymeric inlay layer having a first surface and a second surface, further comprising a first multi-layer film which is disposed on the first surface of the polymeric inlay layer, and further comprising a first polymeric overlay layer which is disposed on said first multi-layer film, such that the layer order is polymeric inlay layer, first multi-layer film and first polymeric overlay layer, wherein said first multi-layer film comprises: (i) a polyester base layer (B) comprising a crystallisable polyester (P.sub.B), and further comprising titanium dioxide in an amount of from about 1 to about 30 wt % by total weight of the base layer; and (ii) a first heat-sealable copolyester layer (A1) disposed on a first surface of said polyester base layer; and (iii) optionally a second heat-sealable copolyester layer (A2) disposed on a second surface of said polyester base layer, wherein the copolyester (CP.sub.A) of each of the first and optional second heat-sealable copolyester layers is independently selected from copolyesters (I-CP.sub.A) derived from repeating units consisting of a first aromatic dicarboxylic acid, a second aromatic dicarboxylic acid and an aliphatic glycol; and wherein said first multi-layer film is obtained by a process comprising heat-setting at a temperature of greater than 225 C. and preferably in the range of 227 to 235 C.

7. A multi-layer card according to claim 5 or 6 wherein the copolyester (CP.sub.A) is selected from copolyesters derived from terephthalic acid, isophthalic acid and ethylene glycol, preferably wherein the isophthalic acid is present in an amount of from about 10 to from about 20 mol % or from about 15 to about 20 mol % or from about 10 to about 15 mol % of the acid fraction of the copolyester.

8. A multi-layer card according to any preceding claim wherein the crystallisable polyester (P.sub.B) of the base layer is selected from polyethylene terephthalate (PET) and polyethylene 2,6-naphthalate (PEN).

9. A multi-layer card according to any preceding claim wherein the polyester base layer comprises a copolyester CP.sub.B derived from repeating units consisting of one or more aromatic dicarboxylic acid(s) and one or more diols selected from aliphatic diols and cycloaliphatic diols, and optionally one or more aliphatic dicarboxylic acid(s), and preferably said copolyester is selected from (i) copolyesters derived from repeating units consisting of a first aromatic dicarboxylic acid, a second aromatic dicarboxylic acid and an aliphatic glycol; and (ii) copolyesters derived from repeating units consisting of an aromatic dicarboxylic acid, an aliphatic glycol and a cycloaliphatic glycol.

10. A multi-layer card according to any preceding claim wherein copolyester CP.sub.B is selected from (i) a copolyester derived from repeating units consisting of terephthalic acid, isophthalic acid and ethylene glycol, preferably wherein the isophthalic acid is present in an amount of from about 10 to about 20 mol % or from about 15 to about 20 mol % or from about 10 to about 15 mol % of the acid fraction of the copolyester; and (ii) a copolyester derived from repeating units consisting of terephthalic acid, ethylene glycol and 1,4-cyclohexanedimethanol, preferably wherein the molar ratio of the 1,4-cyclohexanedimethanol to the ethylene glycol is in the range from 30:70 to 35:65.

11. A multi-layer card according to any preceding claim wherein copolyester CP.sub.B is present in the base layer in amounts of no more than about 75%, preferably at least about 20%, preferably at least about 30%, preferably at least about 35% by weight, based on the total weight of the base layer (B), and/or wherein where the copolyester CP.sub.B is derived from repeating units consisting of a first aromatic dicarboxylic acid, a second aromatic dicarboxylic acid and an aliphatic glycol the total amount of said second aromatic dicarboxylic acid in the polyester base layer is from about 3 to about 15 wt % by total weight of the base layer.

12. A multi-layer card according to any preceding claim wherein the polyester base layer further comprises a copolyesterether, preferably in an amount of from about 0.2 to about 10 wt % relative to the total weight of the polyester base layer.

13. A multi-layer card according to claim 12 wherein the copolyesterether comprises at least one polyester block and at least one polyether block wherein the ratio of polyester:polyether is in the range 25-55:45-75 by weight % of the copolyesterether.

14. A multi-layer card according to claim 12 or 13 wherein the copolyesterether comprises at least one polyester block of an alkylene terephthalate, and wherein the copolyesterether comprises at least polyether block which is a poly(alkylene oxide) glycol selected from poly(ethylene oxide) glycol, poly(propylene oxide) glycol and poly(tetramethylene oxide) glycol.

15. A multi-layer card according to any preceding claim wherein the polyester base layer (B) is oriented, preferably biaxially oriented, and/or wherein the first heat-sealable layer and the optional second heat-sealable layer are amorphous.

16. A multi-layer card according to any preceding claim wherein said first multi-layer film is a coextruded multi-layer film.

17. A multi-layer card according to any preceding claim wherein said first multi-layer film is opaque, and preferably exhibits a Transmission Optical Density (TOD) of at least 1.0.

18. A multi-layer card according to any preceding claim wherein said first multi-layer film is white, and preferably exhibits a whiteness index of at least 85, and/or wherein said first multi-layer film exhibits an L* value of greater than 92.00; and an a* value in the range from 2.00 to 0.50; and a b* value in the range from 4.00 to 1.00.

19. A multi-layer card according to any preceding claim wherein said titanium dioxide is rutile titanium dioxide.

20. A multi-layer card according to any preceding claim wherein the amount of titanium dioxide in the base layer is in the range from about 10 to about 15% by weight, relative to the total weight of the polyester layer.

21. A multi-layer card according to any preceding claim wherein said titanium dioxide particles are coated by an organic coating, preferably wherein said organic coating does not comprise or is not derived from a silane, preferably wherein the organic coating is not or does not comprise a polysiloxane.

22. A multi-layer card according to claim 21 wherein said organic coating is an organophosphorus compound.

23. A multi-layer card according to any preceding claim wherein the titanium dioxide particles are coated with an alkylphosphonic acid or an ester of an alkylphosphonic acid wherein the alkylphosphonic acid contains from 6 to 22 carbon atoms.

24. A multi-layer card according to claim 23 wherein the alkylphosphonic acid or ester thereof has the formula P(R)(O)(OR.sup.1)(OR.sup.2), wherein: R is an alkyl group or a cycloalkyl group containing 6 to 22 carbon atoms; and R.sup.1 and R.sup.2 are each hydrogen, an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group.

25. A multi-layer card according to claim 24 wherein R.sup.1 and R.sup.2 are independently selected from hydrogen and hydrocarbyl groups containing up to 10 carbon atoms, and preferably R.sup.1 and R.sup.2 are hydrogen.

26. A multi-layer card according to claim 23, 24 or 25 wherein the alkyl group of said alkylphosphinic acid, or R, contains from 6 to 14 carbon atoms and is a straight chain alkyl group.

27. A multi-layer card according to claim 23, 24, 25 or 26 wherein the alkylphosphonic acid or ester thereof is selected from n-octylphosphonic acid and its esters, n-decylphosphonic acid and its esters, 2-ethylhexylphosphonic acid and its esters and camphyl phosphonic acid and its esters.

28. A multi-layer card according to claim 21 wherein said organic coating is a polymeric organic coating.

29. A multi-layer film according to claim 28 wherein said titanium dioxide particles are obtainable by dispersing titanium dioxide particles in water at a pH value higher than the isoelectric point of said titanium dioxide particles (and preferably at a pH above 7 and preferably at a pH of 9 to 11) in the presence of a dispersing agent comprising a polymeric polybasic acid or a salt thereof to produce particles having a modified isoelectric point; adjusting the pH of the dispersion to a value below 9 but above the modified isoelectric point of the particles; and polymerising in the presence of the dispersion so produced one or more ethylenically unsaturated monomer(s) so that said titanium dioxide particles are coated with polymerised monomer.

30. A multi-layer card according to claim 21 or 29 wherein said coated titanium dioxide particles comprise a coherent inner coating formed from a dispersing agent comprising a polymeric polybasic acid or a salt thereof and an outer coating formed from the polymerisation of one or more ethylenically unsaturated monomer(s).

31. A multi-layer card according to claim 21 or 29 wherein said coated titanium dioxide particles comprise a polymeric coating formed from the polymerisation of one or more ethylenically unsaturated monomer(s) wherein a dispersing agent comprising a polymeric polybasic acid or a salt thereof is incorporated into the polymeric coating during polymerisation.

32. A multi-layer card according to any of claims 29 to 31 wherein said polymeric polybasic acids are selected from polysulphonic acids, polyphosphonic acids and polycarboxylic acids, and preferably from polycarboxylic acids, or salts thereof.

33. A multi-layer card according to any of claims 29 to 32 wherein said polymeric polybasic acids are in salt form and wherein the acids are partially or fully neutralised, and/or the salts are the alkali metal salts or ammonium salts.

34. A multi-layer card according to claim 32 or 33 wherein said polymeric polybasic acids are selected from polysulphonic acids selected from lignosulphonates, petroleum sulphonates and poly(styrene sulphonates), including poly(sodium 4-styrene sulphonate), or wherein said polymeric polybasic acids are selected from polymaleic acids, polyacrylic acids, substituted acrylic acid polymers, acrylic copolymers, including copolymers of an acrylic acid with sulphonic acid derivatives, including 2-acrylamido, 2-methyl propane sulphonic acid.

35. A multi-layer card according to any of claims 29 to 34 wherein the amount of dispersing agent is from about 0.05 to about 5.0 wt %, preferably from about 0.1 to about 1.0 wt %, by weight of the titanium dioxide particle.

36. A multi-layer card according to any of claims 29 to 35 wherein said ethylenically unsaturated monomer is polymerisable in aqueous solvents, preferably wherein the polymer produced is insoluble in water and optionally cross-linked by a cross-linking agent.

37. A multi-layer card according to any of claims 29 to 36 wherein said ethylenically unsaturated monomer is selected from aliphatic and aromatic compounds containing a polymerisable unsaturated group, preferably wherein the polymerisable unsaturated group is selected from unsaturated carboxylic acids and unsaturated carboxylic acid esters.

38. A multi-layer card according to any of claims 29 to 37 wherein said ethylenically unsaturated monomer is an acidic monomer selected from acrylic acid, methacrylic acid, itaconic acid, maleic acid or its anhydride, fumaric acid and crotonic acid, and esters of said acidic monomers, including methyl acrylate, ethyl acrylate, methyl methacrylate, butyl acrylate and ethyl methacrylate, and preferably wherein said ethylenically unsaturated monomer is selected from styrene, vinyl toluene, alpha methylstyrene, ethylene, vinyl acetate, vinyl chloride, acrylonitrile, and fluorinated monomers including fluorinated alkenes, fluorinated ethers, fluorinated acrylic and methacrylic acids and esters thereof and fluorinated heterocyclic compounds, and preferably wherein said ethylenically unsaturated monomer is selected from unsaturated carboxylic acids and unsaturated carboxylic acid esters, preferably from methyl acrylate, ethyl acrylate, butyl acrylate, butyl methacrylate, vinyl acetate and vinyl isobutylether.

39. A multi-layer card according to any of claims 29 to 38 wherein said polymeric organic coating is cross-linked, preferably by virtue of the presence of one or more cross-linking agent(s), preferably wherein the cross-linking agent is selected from di- and poly-functional ethylenically unsaturated monomers, preferably from ethylene glycol dimethacrylate, ethylene glycol diacrylate, allyl methacrylate, allyl acrylate, 1,3-butanediol diacrylate, divinyl benzene and 1,3-butanediol dimethacrylate, preferably wherein said cross-linking agent in an amount of from about 1 wt % to about 20 wt %, preferably from about 1 wt % to about 10 wt %, based on the total weight of the ethylenically unsaturated monomer(s)

40. A multi-layer card according to any of claims 21 to 39 wherein the organic coating is present in an amount of from about 0.1 to about 200 wt %, preferably from about 0.1 to about 100 wt %, from about 0.5 to about 100 wt %, from about 2.0 to about 20 wt %, by weight of the titanium dioxide.

41. A multi-layer card according to any of claims 21 to 40 wherein the volume ratio of the titanium dioxide particle particles to the organic coating is from 1:1 to 1:25 by volume, and preferably from 1:2 to 1:8.

42. A multi-layer card according to any of claims 21 to 41 wherein said coated titanium dioxide particles coated by an organic coating have a volume-distributed median primary particle diameter in the range from 0.15 to 0.25 m.

43. A multi-layer card according to any preceding claim wherein said titanium dioxide particles carry an inorganic coating, and where an organic coating is present then the organic coating is coated onto said inorganic-coated titanium dioxide particles.

44. A multi-layer card according to any preceding claim wherein the thickness of the polyester base layer (B) is in the range from 100 to 350 m, and the thickness of each of the first and second heat-sealable layers (A1) and (A2) is in the range of from about 0.5 to about 50 m, and wherein the thickness of polyester base layer (B) is greater than the thickness of each of the first and second heat-sealable layers (A1) and (A2).

45. A multi-layer card according to any preceding claim wherein said first multi-layer film exhibits at least one and preferably all of the following properties: (i) an Elongation To Break (ETB) in each of the longitudinal and transverse directions of the film of at least 250%; and (ii) a delamination resistance to a 100 m uncoated PVC overlay film of at least 5 N/cm, preferably at least 10 N/cm, preferably at least 15 N/cm, preferably at least 25 N/cm.

46. A multi-layer card according to any preceding claim wherein said first multi-layer film exhibits a delamination resistance to an uncoated 100 m PVC overlay film of at least 5N/cm, preferably at least 10 N/cm, preferably at least 15 N/cm, preferably at least 25 N/cm.

47. A multi-layer card according to any preceding claim further comprising a second multi-layer film which is disposed on a second surface of the polymeric inlay layer, and optionally further comprising a second polymeric overlay layer disposed on said second multi-layer film, such that the layer order is second polymeric overlay layer, second multi-layer film, polymeric inlay layer, first multi-layer film and first polymeric overlay layer, wherein said second multi-layer film is a film according to the definition of the first multi-layer film in any of claims 1 to 46 wherein the first and second multi-layer films may be the same as or different to each other, preferably wherein said second multi-layer film is the same as the first multi-layer film, and preferably wherein said second polymeric overlay layer is the same as said first polymeric overlay layer.

48. A multi-layer card according to any preceding claim wherein there is no intervening adhesive layer between the polymeric inlay layer and said multi-layer film.

49. A multi-layer card according to any preceding claim wherein there is no intervening adhesive layer between a polymeric overlay layer and said multi-layer film.

50. A multi-layer card according to any preceding claim wherein said polymeric inlay layer and said polymeric overlay layer are independently selected from polyester, polycarbonate, polyolefin, PVC, ABS and paper, and preferably from PVC.

51. A multi-layer card according to any preceding claim wherein said polymeric overlay layer is optically clear.

52. A multi-layer card according to any of claims 47 to 52 wherein the multi-layer card has a thickness in the range from 250 to 850 m.

53. A multi-layer film comprising: (i) a polyester base layer (B) comprising a crystallisable polyester (P.sub.B), and further comprising titanium dioxide in an amount of from about 1 to about 30 wt % by total weight of the base layer; (ii) a first heat-sealable copolyester layer (A1) disposed on a first surface of said polyester base layer; and (iii) optionally a second heat-sealable copolyester layer (A2) disposed on a second surface of said polyester base layer, wherein the copolyester (CP.sub.A) of each of the first and optional second heat-sealable copolyester layers is independently selected from amorphous copolyesters (ACP.sub.A) derived from an aliphatic diol and a cycloaliphatic diol and at least one aromatic dicarboxylic acid, and the polyester base layer (B) further comprises a copolyester (CP.sub.B) in an amount of at least about 20% by weight based on the total weight of the base layer (B).

54. A multi-layer film according to claim 53 wherein said multi-layer film is further defined according to any of claim 4 or 5 or 7 to 46 when dependent on claim 4 or 5.

55. A multi-layer film comprising: (i) a polyester base layer (B) comprising a crystallisable polyester (P.sub.B), and further comprising titanium dioxide in an amount of from about 1 to about 30 wt % by total weight of the base layer; and (ii) a first heat-sealable copolyester layer (A1) disposed on a first surface of said polyester base layer; and (iii) optionally a second heat-sealable copolyester layer (A2) disposed on a second surface of said polyester base layer, wherein the copolyester (CP.sub.A) of each of the first and optional second heat-sealable copolyester layers is independently selected from copolyesters (I-CP.sub.A) derived from repeating units consisting of a first aromatic dicarboxylic acid, a second aromatic dicarboxylic acid and an aliphatic glycol; and wherein the multi-layer film is obtained by a process comprising heat-setting at a temperature of greater than 225 C. and preferably in the range of 227 to 235 C.

56. A multi-layer film according to claim 55 wherein said multi-layer film is further defined according to any of claims 7 to 46.

Description

EXAMPLES

[0145] In the following discussion, intrinsic viscosity values are those measured on the polymer chip unless otherwise specified, and reference to PETG is to a copolyester of terephthalic acid, 1,4-cyclohexanedimethanol and ethylene glycol (33:67 CHDM:EG) (Skygreen PN100 (IV=0.70)) unless otherwise specified.

Example 1

[0146] Polyester composition P1 contains: [0147] (i) 39.3% of PET homopolymer [0148] (ii) 40.2% of an IPA-containing PET-based copolyester (TA:IPA=82:18; IV=0.67) [0149] (iii) 25% TiO.sub.2-containing PET masterbatch containing 50% of rutile TiO.sub.2 (Tioxide TR28). [0150] (iv) 8% copolyesterether (Hytrel 4068; DuPont)

[0151] A multi-layer film comprising a base layer (B) of polyester composition P1 above and two outer layers A1 and A2 of PETG was extruded and cast using a standard melt coextrusion system. The coextrusion system was assembled using two independently operated extruders which fed separate supplies of polymeric melt to a standard coextrusion block or junction at which these streams were joined. From the coextrusion block, the melt-streams were transported to a conventional, flat film extrusion die which allowed the melt curtain to be cast from the common coextrusion die at 275 C., and then quenched in temperature onto a rotating, chilled metal drum. The cast film was collected at a process speed of about 3 m/min and was approximately 300 mm in width. The cast extrudate was stretched in the direction of extrusion to approximately 2.9 times its original dimensions at a temperature of 82 C. The cooled stretched film was then passed into a stenter oven at a temperature of 115 C. where the film was dried and stretched in the sideways direction to approximately 3.4 times its original dimensions. The biaxially stretched film was heat-set at 210 C. The average thickness of the final film was about 158 m and comprised three layers having an ABA structure, wherein the outer layers (A1) and (A2) were each about 17 m thick. The optical density was 1.06; the L* value was 92.2; the whiteness index was 99.9; and the 60 gloss was 101.

[0152] The multi-layer film was made into a card having the structure shown in FIG. 1. The overlay is an uncoated PVC film (100 m; Bilcare Sicoplast167). The inlay is a white uncoated PVC film (270 m; Bilcare Sicosmart307 T1). The cards were prepared by laminating sheets of each of the layers in a Carver press at 140 C. for 15 minutes at 6000 kg pressure, cooling to 50 C., releasing the pressure, removing the laminate from the press, and cutting the laminate into cards having dimensions 8654.5 mm. The cards were then tested for delamination resistance to the PVC overlay using the test method described herein and the average overlay peel strength was 21.2 N/cm.

[0153] The multi-layer film was also made into a card in which a single multi-layer film was laminated to the uncoated PVC overlay film as described above and the white uncoated PVC inlay film (270 m; Bilcare Sicosmart307 T1) described above. The cards were then tested for delamination resistance to the PVC inlay using the test method described herein and in all test samples the card was found to be impossible to peel.

Comparative Example 1

[0154] A multi-layer film similar to that described in Example 1 was prepared, except with the following significant differences: [0155] (i) the first and second copolyester layers (A1 and A2) were an TA/IPA-copolyester (TA:IPA=82:18), rather than a PETG copolyester; [0156] (ii) no TA/IPA-copolyester was blended into the polyester base layer (B); and [0157] (iii) an anatase TiO.sub.2 (Tioxide A-HRF) was used in the base layer, rather than a rutile TiO.sub.2.

[0158] A multi-layer card was made and tested in a manner similar to that described in Example 1. This is a conventional multi-layer card which is the standard structure for currently commercially available cards, substantially in accordance with the best teaching of U.S. Pat. No. 7,232,602-B, and it was this structure on which the present inventors sought to improve. The overlay peel strength was only 2.9 N/cm, as measured in the test described hereinabove. In the inlay peel test described herein, it was easy to peel the multi-layer film away from the inlay.

Examples 2 to 15

[0159] Further multi-layer films were prepared using the procedure according to Example 1, with the differences noted in Table 1 below. The TiO.sub.2 grade used was the same as for Example 1, except for Examples 4, 5, 6, 9 and 13 which used the same anatase TiO.sub.2 of Comparative Example 1. The overlay peel strengths are shown in Table 1 below. The films of Examples 2, 3, 8, 9, 10, 11, 12 and 13 showed particularly strong delamination resistance to a PVC inlay (assessed using the test method described herein), and in particular Examples 2, 3, 9, 10, 11 and 12 which were found to be impossible to peel.

[0160] The results demonstrate that the cards of the present invention exhibit surprisingly superior bond strength between the multilayer film and the polymeric overlay, surprisingly improved cohesive strength in the polyester base layer, and surprisingly superior bond strength between the multi-layer film and the polymeric inlay. The best performing cards with the greatest delamination resistance are those wherein the heat-seal layer is selected from amorphous copolyesters (ACP.sub.A) derived from an aliphatic diol and a cycloaliphatic diol and at least one aromatic dicarboxylic acid and wherein the polyester base layer further comprises a copolyester (CP.sub.B). Without wishing to be bound by theory, the inventors believe that the use of such amorphous copolyesters (ACP.sub.A) in the heat-seal layer shifts the locus of the plane of failure of the card into the polyester base layer of the multi-layer film, and the use of the copolyester (CP.sub.B) and preferably also rutile titanium dioxide in the base layer increases the cohesive strength of the base layer, resulting in an unexpectedly high delamination resistance.

[0161] The cards of the present invention therefore exhibit superior security and tamper-resistance.

TABLE-US-00001 TABLE 1 PET wt % in Copolyester in Copolyester IPA wt % in Heat-set Overlay peel Sample Layer A polymer layer B layer B wt % in layer B B layer temperature ( C.) strength (N/cm) C. Ex. 1.sup.a 18% IPA co-PET 83.9 None 0.0 0.0 225 2.9 Ex. 1 PETG 39.3 18% IPA co-PET 40.2 7.2 210 21.2 Ex. 2 PETG 39.3 18% IPA co-PET 40.2 7.2 220 23.5 Ex. 3 PETG 39.3 18% IPA co-PET 40.2 7.2 230 24.9 Ex. 4.sup.a 18% IPA co-PET 39.3 18% IPA co-PET 40.2 7.2 230 6.3 Ex. 5.sup.a 18% IPA co-PET 83.9 None 0.0 0.0 230 5.8 Ex. 6.sup.a PETG 83.9 None 0.0 0.0 225 5.0 Ex. 7 PETG 83.9 None 0.0 0.0 230 5.8 Ex. 8 PETG 63.9 18% IPA co-PET 20.0 3.6 230 16.6 Ex. 9.sup.a PETG 60.1 18% IPA co-PET 23.8 4.3 230 10.4 Ex. 10 PETG 46.0 18% IPA co-PET 33.5 6.0 230 22.3 Ex. 11 PETG 37.6 18% IPA co-PET 41.9 7.5 230 25.7 Ex. 12 PETG 30.5 18% IPA co-PET 49.0 8.8 230 32.7 Ex. 13.sup.a PETG 12.5 12% IPA co-PET 71.4 8.6 200 8.1 Ex. 14 PETG 67.3 PETG + 18% IPA co- 19.4 1.7 230 13.6 PET (50:50) Ex. 15 PETG 67.3 PETG 19.4 0.0 230 13.2 .sup.aanatase TiO.sub.2