FILMS HAVING SPECIAL PROPERTIES

Abstract

The invention relates to a film containing a special polycarbonate or copolycarbonate of the formula (Ia), (I-2), (I-3) or (I-4) and to the use of the film in a security document and in a layer structure.

Claims

1. A film comprising i) 85% to 95% by weight of one of a polycarbonate or a copolycarbonate of the formula (Ia), (I-2), (I-3) or (I-4), where (Ia) ##STR00012## in which R.sup.1 and R.sup.2 are independently hydrogen, halogen, C.sub.1-C.sub.8-alkyl, C.sub.5-C.sub.6-cycloalkyl, C.sub.6-C.sub.10-aryl, C.sub.7-C.sub.12-aralkyl, m is an integer from 4 to 7, R.sup.3 and R.sup.4 can be are chosen individually for each X and are independently hydrogen or C.sub.1-C.sub.6-alkyl and X is carbon, with the proviso that for at least one atom X, R.sup.3 and R.sup.4 both represent alkyl, or wherein ##STR00013## in which R.sup.5 is a C.sub.1- to C.sub.4-alkyl radical, aralkyl radical or aryl radical, ii) 0.1% to 5% by weight of a first additive; iii) optionally 0.1% to 15% by weight of a second additive different than the first additive; wherein the first additive ii) comprises or is an antistatic compound.

2. The film as claimed in claim 1, wherein the first additive ii) is selected from the group consisting of quaternary ammonium or phosphonium salts of a partly fluorinated or perfluorinated organic acid or quaternary ammonium or phosphonium hexafluorophosphates, and mixtures of at least two of these.

3. The film as claimed in claim 1, wherein the antistatic compound is selected from the group consisting of quaternary ammonium salts of a partly fluorinated or perfluorinated organic acid or quaternary ammonium hexafluorophosphates, and mixtures of at least two of these.

4. The film as claimed in claim 1, wherein the polycarbonate or copolycarbonate has an average molecular weight Mw within a range from 10 000 to 500 000 g/mol.

5. The film as claimed in claim 1, wherein the polycarbonate or copolycarbonate has been prepared partly from the starting materials selected from the group consisting of: ##STR00014## and mixtures of at least two of these.

6. The film as claimed in claim 1, wherein the polycarbonate or copolycarbonate includes the starting compound (Ib) within a range from 10% by weight to 90% by weight based on the total mass of the polycarbonate or copolycarbonate, or the polycarbonate or copolycarbonate has a molar ratio of (Ib) to other bisphenol A derivatives within a range from 1:10 to 10:1.

7. The film as claimed in claim 1, wherein the film has at least one of the following properties: (A) roughness in accordance with ISO 4288:1996 within a range from 2 μm to 30 μm; (B) transparency within a range from 2% to 92%, measured to ISO 13468-2:2006-07; (C) gloss within a range from 10 to 110 to ISO 2813, 2015-02; (D) scratch resistance within a range from 4B to 3H, measured according to DIN EN ISO 15184-2011-05; (E) a Vicat softening temperature within a range from 160° C. to 230° C., according to ISO 306:2004 (method B120 50N; 120° C./h); (F) surface resistance <10.sup.14Ω, according to DIN IEC 93:1980 (from Fischer).

8. The film as claimed in claim 1, wherein the further additive is selected from the group consisting of a dye, a pigment, and a combination of these.

9. The film as claimed in claim 1, wherein the pigment is selected from the group consisting of titanium dioxide, zirconium dioxide, calcium carbonate, barium sulfate, and a mixture of at least two of these.

10. The film as claimed in claim 1, wherein the further additive is introduced into the film by a process having at least the following steps: D1. at least partly coating the film with a layer containing a dye or pigment, D2. at least partly irradiating the film from D1. with focused nonionizing electromagnetic radiation, wherein there is partial coloring of the film only at the sites irradiated in step D2.

11. A security document including the film as claimed in claim 1 having security-relevant data.

12. In a process for production of a laser-engravable film, the improvement comprising including a polycarbonate or a copolycarbonate of the formula ##STR00015## in which R.sup.1 and R.sup.2 are independently hydrogen, halogen, C.sub.5-C.sub.6-cycloalkyl, C.sub.6-C.sub.10-aryl, and C.sub.7-C.sub.12-aralkyl, m is an integer from 4 to 7, R.sup.3 and R.sup.4 are chosen individually for each X and are independently hydrogen or C.sub.1-C.sub.6-alkyl and X is carbon, with the proviso that, on at least one atom X, R.sup.3 and R.sup.4 are both alkyl, or ##STR00016## in which R.sup.5 is a C.sub.1- to C.sub.4-alkyl radical, aralkyl radical or aryl radical.

13. A layer construction comprising the following layers: S1. a film as claimed in claim 1, S2. optionally a further layer or film, S3. optionally a further film as claimed in claim 1, S4. optionally a paper or board layer.

14. The layer construction as claimed in claim 13, comprising at least one further film S2., wherein the further film S2. includes a thermoplastic selected from one or more polycarbonates or copolycarbonates based on diphenols, poly- or copolyacrylates and poly- or copolymethacrylates, poly- or copolymers of styrene, thermoplastic polyurethane(s) and polyolefin(s), poly- or copolycondensates of terephthalic acid having a fraction of cyclohexane-1,4-dimethanol, cyclohexane-1,3-dimethanol and/or 2,2,4,4-tetramethylbutane-1,3-diol, and blends containing at least one polycarbonate or copolycarbonate.

15. The layer construction as claimed in claim 14, characterized in that the layer construction comprises a further layer containing at least one thermoplastic and at least one laser-sensitive additive.

Description

[0183] In the figures

[0184] FIG. 1 Diagram of the comparison of the roughness and optical density of films according to the invention and not according to the invention

[0185] FIG. 2 Diagram of the comparison of the gloss and optical density of films according to the invention and not according to the invention

[0186] The films according to the invention are notable for higher optical density compared to the comparative films not according to the invention, as can be seen from FIGS. 1 and 2. Optical density was ascertained using the Techkon DENS color densitometer according to the recommendations of DIN 5033 Parts 1-9: Colorimetry and the calculations according to ISO 5-3:2009 (E): Photography—Measuring Optical Density—Part 3.

EXAMPLES

Example 1

[0187] ##STR00011##

[0188] 183.3 g (0.80 mol) of bisphenol A (2,2-bis(4-hydroxyphenyl)propane), 61.1 g (0.20 mol) of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 336.6 g (6 mol) of KOH and 2700 g of water were dissolved with stirring in an inert gas atmosphere. A solution of 1.88 g of phenol in 2500 ml of methylene chloride was then added. 198 g (2 mol) of phosgene were introduced into the well-stirred solution at pH 13 to 14 and 21° C. to 25° C. 1 ml of ethylpiperidine was then added and the mixture was stirred for 45 min. The bisphenoxide-free aqueous phase was removed and the organic phase acidified with phosphoric acid, neutralized by washing with water and freed of solvent. The polycarbonate showed a relative solution viscosity of 1.255.

[0189] The glass transition temperature of the polymer was determined as 157° C. (DSC).

Example 2

[0190] As in example 1, a mixture of 127.1 g (0.56 mol) of bisphenol A and 137.7 g (0.44 mol) of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane was converted to the polycarbonate.

[0191] The polycarbonate showed a relative solution viscosity of 1.263.

[0192] The glass transition temperature of the polymer was determined as 167° C. (DSC).

Example 3

[0193] As in example 1, a mixture of 149.0 g (0.65 mol) of bisphenol A and 107.9 g (0.35 mol) of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane was converted to the polycarbonate.

[0194] The polycarbonate showed a relative solution viscosity of 1.263.

[0195] The glass transition temperature of the polymer was determined as 183° C. (DSC).

Example 4

[0196] As in example 1, a mixture of 91.6 g (0.40 mol) of bisphenol A and 185.9 g (0.60 mol) of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane was converted to the polycarbonate.

[0197] The polycarbonate showed a relative solution viscosity of 1.251.

[0198] The glass transition temperature of the polymer was determined as 204° C. (DSC).

Example 5

[0199] As in example 1, a mixture of 44.2 g (0.19 mol) of bisphenol A and 250.4 g (0.81 mol) of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane was converted to the polycarbonate.

[0200] The polycarbonate showed a relative solution viscosity of 1.248.

[0201] The glass transition temperature of the polymer was determined as 216° C. (DSC).

Example 6: Compounding a Masterbatch for Production of the Layer Containing a Thermoplastic and an Antistat Additive

[0202] Production of the antistat additive compound was conducted with conventional twin-screw compounding extruders (e.g. ZSK 32) at processing temperatures of 250 to 330° C. that are customary for polycarbonate.

[0203] A masterbatch having the following composition was compounded and subsequently pelletized: [0204] 90% by weight of polycarbonate from example 3 [0205] 10% by weight of N,N,N,N-dimethyldiisopropylammonium perfluorobutanesulfonate.

Examples 7 to 10 of Film Extrusion

[0206] The films were extruded in a width of 450 mm using the plastic from example 3.

[0207] The system used consisted of [0208] an extruder having a screw of diameter (D) 75 mm and length 33×D. The screw has a devolatilization zone; [0209] a melt pump; [0210] a crosshead; [0211] a slot die of width 450 mm; [0212] a three-roll smoothing calendar with horizontal roller orientation, wherein the third roller can swivel by +/−45° relative to the horizontal; [0213] a roll conveyor; [0214] thickness measurement; [0215] a device for double-sided application of protective film; [0216] a takeoff device; [0217] winding station.

[0218] The respective pellet material was supplied to the extruder hopper. The material was melted and conveyed in the barrel/screw plastifying system of the extruder. The material melt was supplied to the smoothing calender, the rolls of which, or the cooling liquid supplied and removed for cooling of the rolls, had the temperature specified in table 1. The final shaping and cooling of the film was effected on the smoothing calender (consisting of three rolls). Structuring of the film surfaces was accomplished using a rubber roll (no. 4 or surface), polished chromium roll (no. 1 surface) or structured steel roll (no. 2 and 6 surface). The rubber roll used for texturing the film surface is described in U.S. Pat. No. 4,368,240 to Nauta Roll Corporation. Subsequently, the film was transported through a takeoff. Thereafter, it is optionally possible to apply a protective PE film to both sides and to wind up the film.

TABLE-US-00001 TABLE 0 Temperature profile of the extruder and die Process parameter Target value (° C.) Actual value (° C.) Barrel zone 1 230.0 217.0 Barrel zone 2 290.0 289.0 Barrel zone 3 295.0 294.0 Devolatilization zone 4 270.0 269.0 Barrel zone 5 305.0 304.0 Barrel zone 6 310.0 309.0 Two-piece flange zone 7 320.0 317.0 Flange before pump zone 8 320.0 333.0 Flange after pump zone 9 320.0 318.0 Flange zone 10 320.0 323.0 Crosshead zone 11 320.0 314.0 Melt conduit zone 12 320.0 314.0 Melt conduit zone 13 330.0 330.0 Right-hand nozzle zone 14 323.0 321.0 Middle nozzle zone 15 330.0 330.0 Left-hand nozzle zone 16 320.0 328.0 Melt pump zone 17 270° C.

TABLE-US-00002 TABLE 1 Running speed and temperature profile of the rolls Linear speed W2: 3.70 m/min T of the cooling liquid (water here) Roll Running Upstream of contact Downstream of contact number speed with the melt with the melt Roll 1: 1.0 m/min 100-112° C.     40° C. Roll 2: 1.5 m/min 120° C. 100° C. Roll 3: 1.00 m/min  130° C. 100° C. Draw rate: 0.992 m/min

TABLE-US-00003 TABLE 2 Surface textures of example films 7 to 10″ Surface texture Composition Example 7 1-4 100% polymer from example 3 Comparative example (not according to the invention) Example 8 6-2 100% polymer from example 3 Comparative example (not according to the invention) Example 9 1-4 90% polymer from example 3 according to the invention 10% compound from example 6 Example 10 6-2 90% polymer from example 3 according to the invention 10% compound from example 6 Example 10′ 7-2 100% polymer from example 3 Comparative example (not according to the invention) Example 10″ 7-2 90% polymer from example 3 not according to the invention 10% compound from example 6

[0219] Films of thickness 100 μm were extruded.

Examples 11 to 16: Toner Printing

[0220] A DIN A4 film specimen of examples 7 to 10 was printed with an HP color laser printer (printer model: Ricoh MP C 3003). The film was printed on the side with the side named in each case.

[0221] Print pattern: full-area black print

[0222] Resolution of the print pattern: 600 dpi.

[0223] The films according to the invention have impeccable printability and showed a faultless printed image, by contrast with the films not according to the invention, which warped in the printing operation and had distortions in the film.

TABLE-US-00004 TABLE 3 Surface textures of example films 11 to 16″ Description Example 11 No. 1 side printed of film from example 7 Comparative example (not according to the invention) Example 12 No. 4 side printed of film from example 7 Comparative example (not according to the invention) Example 13 No. 6 side printed of film from example 8 Comparative example (not according to the invention) Example 14 No. 1 side printed of film from example 9 according to the invention Example 15 No. 4 side printed of film from example 9 according to the invention Example 16 No. 6 side printed of film from example 10 according to the invention Example 16′ No. 7 side printed of film from example 10′ Comparative example (not according to the invention) Example 16″ No. 7 side printed of film from example 10″ according to the invention

Examples 17 to 24: Card Lamination

[0224] The printed films from example 11 to 16″ were placed between two further films based on Makrolon 3108® polycarbonate from Covestro AG. The film stack was placed into a Burkle lamination press and laminated under pressure and temperature. Lamination was effected with the following parameters:

[0225] Temperature: 195° C.

[0226] Low hold pressure during the heating time: 15 N/cm.sup.2

[0227] Heating time: 8 minutes.

[0228] High pressure during the lamination: 300 N/cm.sup.2

[0229] Lamination time: 2 minutes.

[0230] Subsequently, cooling of the press was initiated. Cooling was effected with continued application of pressure. On attainment of a temperature of 38° C., the press was opened.

[0231] Evaluation of Optical Density

TABLE-US-00005 TABLE 4 Evaluation of optical density and gloss of examples 17 to 24 Optical density, printed side Description Roughness Gloss downward, black Example 17 No. 1 side printed of Comparative example 0.00 102.00 82.6 film from example 7 (not according to the invention) Example 18 No. 4 side printed of Comparative example 4.44 16.00 80.4 film from example 7 (not according to the invention) Example 19 No. 6 side printed of Comparative example 13.36 4.90 80.2 film from example 8 (not according to the invention) Example 20 No. 1 side printed of according to the 0.00 102.00 83.0 film from example 9 invention Example 21 No. 4 side printed of according to the 4.67 4.42 79.8 film from example 9 invention Example 22 No. 6 side printed of according to the 11.26 4.86 80.7 film from example invention 10 Example 23 No. 7 side printed of Comparative example 17.59 13.50 79.1 film from example (not according to the 10′ invention) Example 24 No. 7 side printed of according to the 28.54 12.00 79.6 film from example invention 10″

[0232] As can be inferred from table 4, either an increase or approximate matching of the optical density coupled with usually constant gloss values and an increase in optical density with constant roughness after the printing of the films according to the invention from examples 20 to 22 and 24 is apparent by comparison with examples 17 to 19 and 23 not according to the invention, in each case with respect to the corresponding composition. The results were shown visually for the representation of optical density at different roughnesses in FIG. 1 and at different gloss levels in FIG. 2 for examples 17 to 24. However, the crucial feature for films to be printed is the sharpness of the print. It should be noted here that there are regions of gloss and of roughness that produce a poor printed image, whereas the films of the invention will show a good to very good printed image, as can be inferred in table 5.

[0233] Evaluation of the Printed Image

TABLE-US-00006 TABLE 5 Evaluation of the printed image from examples 17 to 24 Description Printed image Example 17 No. 1 side printed of Blurred (−) film from example 7 Example 18 No. 4 side printed of Matt and cloudy (−) film from example 7 Example 19 No. 6 side printed of Matt and cloudy (−) film from example 8 Example 20 No. 1 side printed of Sharp and delimited (+) film from example 9 Example 21 No. 4 side printed of Sharp and delimited (+) film from example 9 Example 22 No. 6 side printed of Sharp and delimited (+) film from example 10 Example 23 No. 7 side printed of Matt and cloudy (−) film from example 10′ Example 24 No. 7 side printed of Sharp and delimited (+) film from example 10″