FILMS HAVING A SCRATCH-RESISTANT COATING AS A COVER LAYER AND LAYERED COMPOSITES COMPRISING SUCH FILMS

Abstract

The invention relates to heteroaromatic compounds, particularly for use in electronic devices. The invention further relates to a method for producing the compounds according to the invention and to electronic devices containing same.

Claims

1.-15. (canceled)

16. A film comprising a thermoplastic film and a coating, wherein the coating has been produced from a coating material composition containing a) urethane (meth)acrylate which has (meth)acryloyl groups and an isocyanate functionality of 1.75 to 2.3, b) acrylated acrylate which still has free isocyanate-reactive groups, c) optionally additives and/or solvents.

17. The film as claimed in claim 16, wherein the components a) and b) are used in a ratio of equivalents of 0.5:1.0 to 1.1:1.0.

18. The film as claimed in claim 16, wherein the urethane (meth)acrylate is obtained by reaction of (a-1) a monohydric alcohol having (meth)acryloyl groups and (a-2) polyisocyanates having an isocyanate functionality in the range from 2.5 to 6.0.

19. The film as claimed in claim 16, wherein the acrylated acrylate has hydroxyl groups as isocyanate-reactive groups.

20. The film as claimed in claim 16, wherein the acrylated acrylate has a viscosity in solution in the range from 2600 to 3400 mPa*s at 23 C.

21. The film as claimed in claim 16, wherein the film is subjected to thermal curing at a temperature of 50 C.

22. The film as claimed in claim 16, wherein the thermoplastic film comprises one or more polycarbonates or copolycarbonates based on diphenols, poly- or copoly(meth)acrylates, poly- or copolycondensates of terephthalic acid or blends thereof.

23. The film as claimed in claim 16, wherein the coating, after thermal curing, has a thickness in the range of 2 to 20 m.

24. A method for producing a film as claimed in claim 16, comprising the steps of: i) providing a thermoplastic film, ii) coating the thermoplastic film with a coating material composition containing a) urethane (meth)acrylate which has (meth)acryloyl groups and an isocyanate functionality of 1.75 to 2.2, b) acrylated acrylate which still has free isocyanate-reactive groups, c) optionally additives and/or solvents, iii) thermally curing the coated film.

25. The method as claimed in claim 24, further comprising the steps of: iv) producing a layer construction comprising a plurality of thermoplastic films, wherein the layer construction, comprises at least one film coated film and wherein the coated side of the film is directed toward the outside, v) optionally applying embossing, preferably embossing on the micrometer scale, to at least one outer side of the layer construction during or after step iv), vi) effecting final curing of the layer construction by means of actinic radiation.

26. The method as claimed in claim 25, wherein in step iv) the layer construction is produced by lamination.

27. The method as claimed in claim 25, wherein in step iv) the layer construction comprises at least two coated films as claimed in claim 16 and wherein the coated side of the film as claimed in claim 16 is in each case directed toward the outside.

28. The method as claimed in claim 25, wherein prior to, during or after step vi) further information is applied by means of laser engraving.

29. A layer construction comprising at least one film as claimed in claim 16, wherein the coated side of the film as claimed in claim 16 is directed toward the outside.

30. The use of a coating material composition containing a) urethane (meth)acrylate which has (meth)acryloyl groups and an isocyanate functionality of 1.75 to 2.3, b) acrylated acrylate which still has free isocyanate-reactive groups, c) optionally additives and/or solvents, for the coating of thermoplastic films.

Description

EXAMPLES

[0119] Makrofol ID 6-2-750061: thermoplastic film based on polycarbonate with a thickness of 100 m from Covestro Deutschland AG
Makrofol ID 4-4-010207: white thermoplastic film based on polycarbonate with a thickness of 450 m from Covestro Deutschland AG
Makrofol ID 320: a single-sidedly coated polycarbonate film with a thickness of 105 m from Covestro Deutschland AG
Makrofol 1-4: thermoplastic film based on polycarbonate with a thickness of 100 m from Covestro Deutschland AG. Surface: high-gloss (=1)/fine matt (=4).
Norilux DC-4: abrasion-resistant, deformable dual cure coating material from Prll KG, Germany
Norilux Hardener 036: hardener for mixing with Norilux DC-4 from Prll KG, Germany

Preparation of the Isocyanate Group-Containing Urethane (Meth)Acrylate

[0120] The isocyanate group-containing urethane (meth)acrylate was prepared in accordance with EP-A 1103572 Isocyanate group-containing urethane (meth)acrylate B:

[0121] An apparatus with stirrer, gas inlet and thermometer is initially charged with 552 g of Desmodur N 3600 (commercial product from Covestro Deutschland AG, Leverkusen; a polyisocyanate containing essentially HDI isocyanurates, NCO content: 23.4% by weight, viscosity 1200 mPa*s at 23 C.) while passing air through (single flask volume per hour) and passing nitrogen over (double flask volume per hour). 1.6 g of 2,6-di-tert-butyl-4-methylphenol are added thereto. The solution is heated to 60 C. while stirring. The heat source is removed and 116.0 g of 2-hydroxyethyl acrylate are added dropwise thereto such that the temperature is between 55 and 65 C. Subsequently, reaction is continued at 60 C. until the NCO content is below 12.5% by weight. The resulting product has a dynamic viscosity of 12 Pa*s at 23 C.

Preparation of the Coating Material Composition of the Coating Composition

Component a)

[0122] 20.9 kg of the isocyanate group-containing urethane (meth)acrylate prepared above are initially charged and mixed with 22.0 kg of diacetone alcohol.

Component b)

[0123] 18.5 kg of Ebecryl 1200 (Allnex S.a.r.l.) are initially charged and mixed with 730 g of Byk 306 (20% in i-methoxy-2-propanol), 870 g of dibutyltin dilaurate (1% in butyl acetate). 1.71 kg of Irgacure 184 (50% in 1-methoxy-2-propanol) and 35.29 kg of a 1:1 mixture of diacetone alcohol and 1-methoxy-2-propanol.
Production of Film 1 Coated in Accordance with the Invention

[0124] The coating solution is applied to a film (Makrofol ID 1-4 of thickness 75 m) by means of a slot coater in a roll-to-roll coating system, to the rough side of the film. Components a) and b) of the coating composition are mixed with one another by means of a static mixer immediately before introduction into the slot coater. The speed of the film was 0.7 m/min.

[0125] The layer thickness of the coating composition was 25-30 m wet and 10-12 m after thermal curing. The thermal curing was effected at 110 C. for 10 min in a circulating air dryer.

[0126] The thus-produced film had a thickness of 80 m.

[0127] The thus-produced, coated film was able to be rolled up tack-free without lamination film, and so it had a high blocking resistance.

Production of a Coated Film 2 (Comparative):

[0128] A coated film 2 was produced according to WO-A 2012/019583, example 4, as follows: Norilux DC-4 was mixed with Norilux Hardener 036 in the ratio 10:1 and homogenized by stirring. This coating material mixture was applied to a 100 m thick Makrofol ID1-4 film by the screen printing method using a screen with a screen density of 70 threads/inch under artificial light containing no UV rays. After applying the coating material layer, the solvents were evaporated in a jet dryer at a temperature of 110 C. for approximately 10 minutes.

[0129] The resulting coated film had a high blocking resistance.

Production of a Coated Film 3 (Comparative)

[0130] In a 15 l tank, Degalan M920 (copolymer based on PMMA, M, =300 000; from Evonik) was dissolved in 1-methoxy-2-propanol at 100 C. (internal temperature) as follows: 4500 g of 1-methoxy-2-propanol were initially charged and 1100 g of Degalan M920 were introduced while stirring. They were rinsed in with 2500 g of 1-methoxy-2-propanol. The dissolving operation took about 4 hours. In this way, a homogeneous, clear, colorless and viscous composition was obtained. After the dissolving operation, the mixture was cooled to room temperature. 1100 g of dipentaerythritol penta-/hexaacrylate (DPHA from Cytec) were diluted separately with 2500 g of I-methoxy-2-propanol. At room temperature, this solution was added to the apparatus and mixed in for 2 hours. 44.0 g of Irgacure 1000 (IGM Resins BV), 22.0 g of Darocure 4265 (IGM Resins BV) and 5.5 g of BYK 333 (BYK) were separately diluted with 400 g of 1-methoxy-2-propanol. On attainment of homogeneity of this solution, it was added to the apparatus and mixed in thoroughly. The mixture was subsequently stirred with exclusion of light for about 6 hours. Yield: 11 363 g. The coating composition had a solids content of 17% and a viscosity (23 C.) of 9000 mPas. In the solids content of the coating composition, the proportion of the high polymer, and likewise the proportion of the reactive diluent, were each 48.4% by weight.

[0131] This coating was applied to a 100 m thick Makrofol ID1-4 film with a dry layer thickness of 10-12 m.

Production of a Coated Film 4 (Comparative)

[0132] The coating of the commercial product Makrofol HF329 (an extruded polycarbonate film that is high-gloss on both sides and is provided on one side with a UV-curable coating system, obtainable with a standard thickness of 280 m) was applied to a 100 m thick Makrofol ID1-4 film with a dry layer thickness of 10-12 m.

Production of a Layer Composite in the Form of a Card

Example 1: Production of a Card Using Film 1 Coated in Accordance With the Invention DIN A4 Films Were Placed Together in Accordance With Diagram

[0133]

TABLE-US-00001 Diagram 1: film 1 with a thickness of 80 m with the coated side lying on the outside 100 m Makrofol ID 6-2 - 750061 450 m Makrofol ID4-4 - 010207 100 m Makrofol ID6-2 - 750061 film 1 with a thickness of 80 m with the coated side lying on the outside

[0134] The film stack as per diagram 1 was placed between two highly polished 500 m thick steel plates from 4 Plate GmbH (Wuppertal, Germany). These steel plates are after-treated plates having a dirt-repellent coating (4 Slide type). The plates contain an engraving for the embossing.

[0135] This construction was placed in a heated laminating press from Brckle (model 50/100) and laminated under the following lamination conditions:

Temperature of the heating press: 190 C.
Specific surface pressure in the heating press: 25 N/cm.sup.2
Residence time in the heating press: 8 minutes
Initiation of the cooling phase, specific surface pressure 150 N/cm.sup.2
Residence time in the cooling press until 38 C. was reached

[0136] Cards corresponding to the check card size (ID 1 format according to ISO/IEC 7810) were punched from the thus-obtained product.

[0137] The card was irradiated from both sides with a UV lamp (mercury lamp from the manufacturer Fusion UV Systems) with a dose of 2.5 J/cm.sup.2. The UV energy was measured by means of a radiometer from International Light Technologies, model ILT490.

Example 2 (Comparative)

[0138] A card was produced as described in example 1. However, Makrofol ID 320 was used instead of film 1. The card was not subjected to UV curing though, since the Makrofol ID 320 film has already undergone final curing.

Example 3 (Comparative)

[0139] A card was produced as described in example 1. However, instead of film 1, film 2 according to diagram 2 was used, the other conditions for production of the card corresponding to those as were described in example 1:

TABLE-US-00002 Diagram 2: 100 m film 2, coated side toward the outside 100 m Makrofol ID6-2---750061 450 m Makrofol ID4-4--010207 100 m Makrofol ID6-2---750061 100 m film 2 with the coated side toward the outside.

Example 4 (Comparative)

[0140] A card was produced as described in example 1. However, film 3 was used instead of film 1.

Example 5 (Comparative)

[0141] A card was produced as described in example 1. However, film 4 was used instead of film 1.

TABLE-US-00003 TABLE 1 Characterization of the cards from examples 1 to 5: Property Ex. 1 Ex. 2(C) Ex. 3(C) Ex. 4(C) Ex. 5(C) Blocking 0 0 0 0 0 resistance Embossing no cracks cracks no no cracks cracks of CLI/MLI cracks Layflat 0 cm only from 0 cm 0 cm 0 cm 100 m thickness <1 cm Solvent 0/0/0/1/2 0/0/0/0/0 1/4/3/5/5 0/0/0/0/1 0/0/0/0/0 resistance Bending test >90 000 >90 000 >80 000 8000 7000 Bending test 30 000 5000 >25 000 5000 5000 after climate treatment Ex.: example; (C): comparative

[0142] Description of the determination of the properties given in table 1:

[0143] Blocking Resistance:

Conventional test methods as described, for instance, in DIN 53150 are insufficient to simulate the blocking resistance of rolled-up, pre-dried coating films, and therefore the following test was employed. The coating materials were applied to Makrofol DE 1-1 films (375 m) with a commercial coating bar (target wet layer thickness 100 m). After a flash-off phase at 20 C. to 25 C. of 10 min, the coated films were dried in an air circulation oven at 110 C. for 10 min. After a cooling phase of 1 min, a commercial GH-XI73 nature pressure-sensitive lamination film (from Bischof und Klein, Lengerich, Germany) was applied without creasing to the dried coating film with a plastic ink roller over an area of 100 mm100 mm. Subsequently, the laminated film piece was subjected to a weight of 10 kg over the full area for 1 hour. Thereafter, the lamination film was removed and the coating surface was assessed visually.

[0144] Under these conditions, all of the films used on both outer sides in examples 1 to 5 are resistant to blocking, i.e. no additional or anomalous structure forms in the region of the stress.

CLI/MLI Structures

[0145] These are structures which in cross section have dimensions of approximately 8080 m.sup.2, and which have been engraved into the steel plates between which the film stack was inserted for the production of the card in examples 1 to 5. These structures must be transferred into the surface of the card during lamination of the cards, without cracks forming in the hard coat. This was assessed by optical microscopy.

Layflat

[0146] A sheet in the A4 format was placed, with the coated side upward, on a planar support. The extent to which the corners or edges are raised from the surface was measured.

Solvent Resistance

[0147] The solvent resistance of the coatings was tested with isopropanol, xylene, 1-methoxy-2-propyl acetate, ethyl acetate, acetone, in technical-grade quality. The solvents were applied to the coating with a soaked cotton pad and protected from vaporization by covering. Unless described otherwise, a contact time of 60 minutes at about 23 C. was observed. After the end of the contact time, the cotton pad is removed and the test surface is wiped clean with a soft cloth. This is followed by visual inspection immediately and after light scratching with a fingernail.

[0148] A distinction is made between the following levels: [0149] 0=unchanged; no change visible; not damageable by scratching. [0150] 1=slight swelling visible, but not damageable by scratching. [0151] 2=change clearly visible, barely damageable by scratching. [0152] 3=noticeable change, surface destroyed after firm fingernail pressure. [0153] 4=severe change, scratched through to substrate after firm fingernail pressure. [0154] 5=destroyed; coating material already destroyed on wiping off the chemical; the test substance is not removable (has eaten into surface).

[0155] The values for the 5 solvents are written as an assessment one after another simply in the aforementioned order of the solvents. Values of 0 and 1 generally constitute passing of the test.

Bending Test

[0156] The bending test was conducted according to ISO 10373-1.

[0157] A first bending test was effected after production of the card and a further bending test (Bending test after climate treatment in table 1) was effected after storage of the card in a climate-controlled chamber for 168 h, at a temperature of 85 C., to assess the bendability of the card even under extreme stress.

Summary of the Results

[0158] The criterion of blocking resistance was satisfied by all outer films used in examples 1 to 5. On embossing of CLI/MLI structures, differences are apparent: while example 2 and example 5 feature exceptional mechanical and chemical resistance, they display cracks in the region of the embossed structures after the lamination. Example 2 is unsuitable with respect to layflat. Solvent resistance in example 3 is unsatisfactory.

[0159] Only examples 1, 2 and 3 prove to be sufficiently flexible in the bending test. Examples 4 and 5 do not pass the customary requirement of >80 000 bending operations even before climate-controlled storage. The materials become fatigued too quickly and already crack after <10 000 bending operations. Examples 2, 4 and 5 clearly become more brittle during the climate-controlled storage and no longer pass the bending test after climate-controlled storage. Only the two systems 1 and 3 are capable of passing the bending test in the required manner before and after climate-controlled storage.

[0160] The properties discussed (embossability, solvent resistance and bending test with and without climate-controlled storage) as a whole show that the use of film 1 as outer layer in a layer composite (example 1) is very advantageous, compared to the other examples chosen, for the use as protective film in security documents.