Aqueous laser-sensitive composition for marking substrates

Abstract

Aqueous composition comprising a color former, a developer, and a binder, wherein (a) the weight ratio between the developer and the color former is in the range of from 1 to 5; (b) the binder comprises an acrylate binder, comprising acrylic acid and styrene, and at least one additional monomer selected from the group consisting of -methyl styrene, ethyl acrylate and 2-ethylhexyl acrylate; and (c) the color former and/or the developer are present in an un-encapsulated form; a process for the preparation of these compositions, substrates coated with this composition and a process for its preparation, and a process for preparing a marked substrate using this composition.

Claims

1. An aqueous composition comprising a color former, a developer, and a binder, wherein (a) the weight ratio between the developer and the color former is in the range of from 1:1 to 5:1; (b) the binder comprises an acrylate binder, comprising acrylic acid and styrene, and at least one additional monomer selected from the group consisting of -methyl styrene, ethyl acrylate and 2-ethylhexyl acrylate; and (c) at least one of the color former and the developer is present in an un-encapsulated form, wherein the developer is a sulfonylurea derivative of the formula:
R.sub.1S(O).sub.2NHXNH-A-BR.sub.2(1), wherein R.sub.1 is unsubstituted or substituted phenyl, naphthyl or C.sub.1-20-alkyl, X is a group of the formula C(NH), C(O) or C(S), A is unsubstituted or substituted phenylene, naphthylene or C.sub.1-12-alkylene, or is an unsubstituted or substituted heterocyclic group, B is a linking group of formula OSO.sub.2, SO.sub.2O, NHSO.sub.2, SO.sub.2NH, SSO.sub.2, OCO, OCONH, NHCO, NHCOO, SCONH, SCSNH, CONHSO.sub.2, OCONHSO.sub.2, NHCH, CONHCO, S, CO, O, SO.sub.2NHCO, OCOO and OPO(OR.sub.2).sub.2, and R.sub.2 is unsubstituted or substituted aryl or benzyl or C.sub.1-20-alkyl, wherein if B is not a linking group of formula OSO.sub.2, R.sub.2 is unsubstituted or substituted phenyl, naphthyl or C.sub.1-8-alkyl, and wherein if B is O, R.sub.2 is not alkyl.

2. The composition according to claim 1, wherein the color former is a fluoran.

3. The composition according to claim 2, wherein the fluoran is at least one selected from the group consisting of 3-dibutylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-isoamylamino)-6-methyl-7-anilinofluoran, 3-dipentylamino-6-methyl-7-anilinofluoran, and 3-(N-ethyl-N-p-tolylamino)-6-methyl-7-anilinofluoran.

4. A substrate coated with the composition of claim 2.

5. A process for preparing a coated substrate, which comprises the step of coating a substrate with the composition of claim 2.

6. A process for preparing a marked substrate, which comprises the steps of i) coating a substrate with the composition of claim 2, and ii) exposing those parts of the coated substrate, where a marking is intended, to energy in order to generate a marking.

7. The composition according to claim 1, wherein the weight ratio between the developer and the color former is in the range of from 1.5:1 to 3:1.

8. A process for preparing the composition of claim 1, which comprises the step of mixing a color former and a developer in a weight ratio in the range of from 1:1 to 5:1; a binder comprising an acrylate binder, comprising acrylic acid and styrene, and at least one additional monomer selected from the group consisting of -methyl styrene, ethyl acrylate and 2-ethylhexyl acrylate; and wherein at least one of the color former and the developer are present in an un-encapsulated form.

9. A substrate coated with the composition of claim 1.

10. A process for preparing a coated substrate, which comprises the step of coating a substrate with the composition of claim 1.

11. A process for preparing a marked substrate, which comprises the steps of i) coating a substrate with the composition of claim 1, and ii) exposing those parts of the coated substrate, where a marking is intended, to energy in order to generate a marking.

12. The process of claim 11, wherein the energy is selected from the group consisting of UV, IR, visible and microwave irradiation.

13. A marked substrate, which is obtained by the process of claim 11.

14. The composition according to claim 1, wherein R.sub.1 as phenyl or naphthyl is unsubstituted or substituted by C.sub.1-8-alkyl, C.sub.1-8-alkoxy or halogen, and wherein R.sub.1 as C.sub.1-20-alkyl is unsubstituted or substituted by C.sub.1-8-alkoxy or halogen.

15. The composition according to claim 1, wherein A as a phenylene or naphthylene group is unsubstituted or substituted by C.sub.1-8-alkyl, halogen-substituted C.sub.1-8-alkyl, C.sub.1-8-alkoxy-substituted C.sub.1-8-alkyl, C.sub.1-8-alkoxy, halogen-substituted C.sub.1-8-alkoxy, C.sub.1-8-alkylsulphonyl, halogen, phenyl, phenoxy or phenoxycarbonyl.

16. The composition according to claim 1, wherein R.sub.2 as aryl is phenyl or naphthyl which is unsubstituted or substituted by C.sub.1-8-alkyl, halogen-substituted C.sub.1-8-alkyl, C.sub.1-8-alkoxy-substituted C.sub.1-8-alkyl, C.sub.1-8-alkoxy, halogen-substituted C.sub.1-8-alkoxy or halogen, wherein R.sub.2 as benzyl is unsubstituted or substituted by the substituents given for R.sub.2 as phenyl or naphthyl, and wherein R.sub.2 as C.sub.1-20-alkyl is unsubstituted or substituted by C.sub.1-8-alkoxy, halogen, phenyl or naphthyl.

17. The composition according to claim 1, wherein the developer is N-(p-toluenesulfonyl)-N-3-(p-toluenesulfonyloxyphenyl)urea.

18. An aqueous composition comprising a color former, a developer, and a binder, wherein (a) the weight ratio between the developer and the color former is in the range of from 1:1 to 5:1; (b) the binder comprises an acrylate binder, comprising acrylic acid and styrene, and at least one additional monomer selected from the group consisting of -methyl styrene, ethyl acrylate and 2-ethylhexyl acrylate; and (c) at least one of the color former and the developer is present in an un-encapsulated form, and wherein the developer is selected from at least one of, 4,4-bis(p-toluenesulphonylaminocarbonylamino)diphenylmethane), 4-hydroxybenzoate derivative of a polypentaerythritol compound with CAS number 378244-93-0, N,N-[sulfonylbis[4,1-phenylene iminocarbonylimino(methylphenylene)]]bis-,C,C-diphenyl ester, ZnCl.sub.2, octylammonium stearate, and ammonium stearate.

19. A process for preparing the composition of claim 18, which comprises the step of mixing a color former and a developer in a weight ratio in the range of from 1:1 to 5:1; a binder comprising an acrylate binder, comprising acrylic acid and styrene, and at least one additional monomer selected from the group consisting of -methyl styrene, ethyl acrylate and 2-ethylhexyl acrylate; and wherein at least one of the color former and the developer are present in an un-encapsulated form.

20. A substrate coated with the composition of claim 18.

21. A process for preparing a coated substrate, which comprises the step of coating a substrate with the composition of claim 18.

22. A process for preparing a marked substrate, which comprises the steps of i) coating a substrate with the composition of claim 18, and ii) exposing those parts of the coated substrate, where a marking is intended, to energy in order to generate a marking.

23. The process of claim 22, wherein the energy is selected from the group consisting of UV, IR, visible and microwave irradiation.

24. A marked substrate, which is obtained by the process of claim 22.

Description

EXAMPLES

Preparation of Coating Compositions

(1) The compositions of the laser active coatings of Examples 1 to 30 are shown in Table 1. All compositions show Newtonian flow behaviour. The color of the compositions is slightly off-white for most of the examples.

(2) Preparation of an Acrylic Binder (Binder A1)

(3) To a 1 liter resin pot fitted with mechanical stirrer, condenser, nitrogen inlet, temperature probe and feed inlets are placed 98.9 g water and 483.9 g Joncryl 8078 which is sold by BASF SE, a solution of an ammonium salt of a low molecular weight (ca. 8000 g/mol styrene acrylic copolymer. The contents are heated to 85 C. and degassed with nitrogen for 30 minutes. A monomer phase is prepared by mixing 192.5 g styrene with 157.5 g 2-ethylhexyl acrylate. An initiator feed is prepared by dissolving 1.97 g ammonium persulfate in 63.7 g water. When the reactor is at temperature and degassed, 0.66 g ammonium persulfate are added to the reactor. After 2 minutes, the monomer and initiator feeds are started appropriate to a 3 and 4 hour feed respectively. The reactor contents are maintained at 85 C. throughout the feeds. After completion of the feeds, the reactor contents are held for a further 1 hour at 85 C. before being cooled down to below 40 C. at which point 0.9 g Acticide LG, a biocide containing chlorinated and non-chlorinated methyl isothiazolones, is added. This results in an emulsion polymer of 49.2% solids, pH 8.3 and a Brookfield RVT viscosity of 1100 cPs.

(4) Preparation of Aqueous Dispersion A (25% by Weight Color Former)

(5) 6 g 3-dibutylamino-6-methyl-7-anilinofluoran (Color former B2, for example Ciba Pergascript Black 2C), 12 g 10% solution of Poval 203 (partially hydrolysed PVA manufactured by Kuraray Co. Ltd.), 5.8 g of water and 0.18 g of 20% Surfynol 104 (wetting agent manufactured by Air Products & Chemicals Inc.; solution in isopropyl alcohol) are mixed and milled to a mean particle size of about 1 micron.

(6) Preparation of Aqueous Dispersion B (25% by Weight Color Developer)

(7) 6 g N-(p-toluenesulfonyl)-N-3-(p-toluenesulfonyloxyphenyl)urea (developer D1; for example Ciba Pergafast 201), 4 g 10% solution of PVA (Poval 203), 13.6 g water and 0.40 g 45% solution Huntsman Dehscofix930 dispersant are mixed and milled to a mean particle size of about 1 micron.

(8) Preparation of Aqueous Dispersion C (Developer)

(9) The following ingredients were mixed and milled with 30.0 g of glass beads until a mean particle diameter of about 1 m in order to obtain 24.0 g of aqueous Dispersion C:

(10) 12.0 g Pergafast 201

(11) 1.25 g Joncryl 678 (32 weight % aqueous solution; neutralised with ammonia)

(12) 0.40 g 45% solution Huntsman Dehscofix930 dispersant, and

(13) 10.35 g water

(14) Preparation of Aqueous Dispersion D (Color Former)

(15) The following ingredients were mixed and milled with 30.0 g of glass beads until a mean particle diameter of about 1 m in order to obtain 24.0 g of aqueous Dispersion D:

(16) 12.0 g Pergascript Black 2C,

(17) 3.75 g Joncryl 678 (32 weight % solution),

(18) 0.20 g Surfynol 104 (20% in isopropyl alcohol), and

(19) 8.05 g water

Example 1

Preparation of Coating Composition

(20) 2.85 g Dispersion A, 4.5 g Dispersion B, 8.85 g Binder A1, and 18.9 g water are mixed and stirred for 10 minutes to produce a white laser active coating dispersion with the composition shown in Table 1.

Examples 2 to 30

(21) The compositions of Examples 2 to 7 were produced in the same manner as Example 1, except that different amounts of reactants were used to arrive at the compositions shown in Table 1. Laser active coating dispersions were obtained in each case.

(22) The compositions of Examples 8 to 10 were produced in the same manner as Example 1, except that instead of 6 g N-(p-toluenesulfonyl)-N-3-(p-toluenesulfonyloxyphenyl)urea the developer D-90 was used. Amounts of reactants were used to arrive at the compositions shown in Table 1. Laser active coating dispersions were obtained in each case.

(23) The compositions of Examples 11 to 30 were produced in the same manner as Example 1, except that different developers, colour formers and binders were used in the required amounts to arrive at the compositions shown in Table 1. Laser active coating dispersions were obtained in each case.

Examples 30a to 30c

(24) The compositions of Examples 30a to 30b are produced in the same manner as Example 1, except that different colour formers are used in the required amounts to arrive at the compositions shown in Table 1. Laser active coating dispersions are obtained in each case.

(25) In Table 1, the following abbreviations are used:

(26) 3-diethylamino-6-methyl-7-anilinofluoran (Color former B1; for example Ciba Pergascript Black 1C).

(27) 3-dibutylamino-6-methyl-7-anilinofluoran (Color former B2; for example Ciba Pergascript Black 2C).

(28) Ciba Latexia 319 (Binder A4) is a styrene butadiene lattice with solids content 50%, particle size 0.12 m, glass transition temperature Tg 28 C. Ciba Latexia 318 (Binder A3) is a styrene butadiene lattice with solids content 50%, particle size 0.12 m, glass transition temperature Tg 22 C. Ciba Latexia 302 (Binder A2) is a styrene butadiene lattice with solids content 50%, particle size 0.15 m, and glass transition temperature Tg 10 C.).

(29) 3-(N-ethyl-N-p-tolylamino)-6-methyl-7-anilinofluoran (color former B4; for example Black ETAC manufactured by Yamada Chemical Co. Ltd.)

(30) 3-di-n-pentylamino-6-methyl-7-anilinofluoran (color former B5; for example Black 305 manufactured by Yamada Chemical Co. Ltd.)

(31) 3-(N-methyl-N-propylamino)-6-methyl-7-anilinofluoran (color former B6; for example Black PSD 300 manufactured by Nippon Soda)

(32) 3-(N-ethyl-N-isoamylamino)-6-methyl-7-anilinofluoran (Color former B7, sold under the tradename S 205 by Yamada Chemical Company)

(33) Phenol, 4,4-sulfonylbis-polymer with 1,1-oxobis(2-chloroethane) (as sold for example under the tradename D90 by Nippon Soda) (developer D2)

(34) Bisphenol A (developer D3)

(35) 4.4hydroxy-bisphenol sulfone (developer D4)

(36) 4-hydroxybenzoate derivative of a polypentaerythritol compound with CAS number 378244-93-0 as sold for example by Asahi Denka Kogyo under the tradename K5 (developer D5)

(37) 4,4-bis(p-toluenesulphonylaminocarbonylamino)diphenylmethane) (as sold for example under the tradename B-TUM) (developer D6)

(38) Carbamic acid, N,N-[sulfonylbis[4,1-phenyleneiminocarbonylimino(methylphenylene)]]bis-, C,C-diphenyl ester (as sold by Asahi Denka Kogyo under the tradename UU) (developer D7)

(39) Latexia 302S (binder A2)

(40) Latexia 707 (binder A5)

(41) Joncryl 682 (binder A6)

(42) Carboset GA2236 (binder A7)

Example 31

Preparation of an Ink (Ink B)

(43) In order to obtain 100.0 g of the ink, the following components were mixed to obtain a white dispersion:

(44) 11.0 g Dispersion D

(45) 22.0 g Dispersion C

(46) 5.9 g ammonia neutralised Joncryl 678

(47) 5.0 g Formapol FP383 wax (sold by Formulated Polymer Products Ltd.) suspended in 56.1 g

(48) Joncryl 90

(49) This ink is then coated on a white board using K-bar 0 with a dry coat weight of 3 g/m.sup.2 and imaged using a CO.sub.2 IR laser (power 0.5 W/speed 1000 mm/sec) to yield a black image of high contrast without any formation of smoke.

(50) This ink is also coated on Tambrite white board (manufactured by Stora Enso) using K-bar 1 with a dry coat weight of about 3 g/m.sup.2. It is then imaged using a 10 W CO.sub.2 laser with the settings intensity 40% and speed 8000 mm/sec to yield a black image of high contrast.

Example 32

Preparation of an Ink (Ink C)

(51) Preparation of Aqueous Dispersion E (50% by Weight Color Former)

(52) 50 g 3-dibutylamino-6-methyl-7-anilinofluoran (Color former B2, for example Ciba Pergascript Black 2C), 25 g 10% solution of Mowiol 4-88 (partially hydrolysed PVA manufactured by Kuraray Co. Ltd.), 24.8 g of water and 0.2 g of Surfynol 104 powder (wetting agent manufactured by Air Products & Chemicals Inc.) are mixed and milled to a mean particle size of about 1 micron.

(53) Preparation of Aqueous Dispersion F (50% by Weight Color Developer)

(54) 50 g N-(p-toluenesulfonyl)-N-3-(p-toluenesulfonyloxyphenyl)urea (developer D1; for example Ciba Pergafast 201), 25 g 10% solution of PVA (Mowiol 4-88) and 25 g water are mixed and milled to a mean particle size of about 1 micron.

(55) In order to obtain 100.0 g of the ink, the following components were mixed to obtain a white emulsion:

(56) 11.0 g Dispersion E

(57) 22.0 g Dispersion F

(58) 5.9 g 32% aqueous ammonia neutralised Joncryl 678 solution

(59) 5.0 g Formapol FP383 Wax, sold by Formulated Polymer Products Ltd. suspended in 56.1 g

(60) Joncryl 90

(61) This ink is then coated on a white board using K-bar 0 with a dry coat weight of 3 g/m.sup.2. and imaged using a CO.sub.2IR laser (power 0.5 W/speed/1000 mmsec) to yield a black image of high contrast, producing no smoke.

(62) TABLE-US-00001 TABLE 1 Developer Color former content Binder content of active of active % weight Aspect No in % weight in % weight as is formulation 1 2.0 B2 3.2 D1 25 A1 sl. off white emulsion 2 2.0 B2 3.2 D1 5 A1 sl. off white emulsion 3 2.0 B2 2.0 D1 25 A1 sl. off white emulsion 4 2.0 B2 4.0 D1 25 A1 sl. off white emulsion 5 2.4 B2 4.8 D1 24 A1 sl. off white emulsion 6 2.7 B2 5.4 D1 23 A1 sl. off white emulsion 7 3.2 B2 6.4 D1 20 A1 sl. off white emulsion 8 2.0 B2 3.2 D2 25 A1 sl. off white emulsion 9 2.0 B2 2.0 D2 25 A1 sl. off white emulsion 10 2.0 B2 4.0 D2 25 A1 sl. off white emulsion 11 2.0 B2 3.2 D3 25 A1 sl. grey emulsion 12 2.0 B2 3.2 D4 25 A1 sl. off white emulsion 13 2.0 B2 3.2 D5 25 A1 sl. grey emulsion 14 2.7 B2 2.7 D6 25 A1 trace grey emulsion 15 2.7 B2 4.3 D6 25 A1 trace grey emulsion 16 2.7 B2 5.4 D6 25 A1 trace grey emulsion 17 2.7 B2 2.7 D7 25 A1 sl. off white emulsion 18 2.7 B2 4.3 D7 25 A1 sl. off white emulsion 19 2.7 B2 5.4 D7 25 A1 sl. off white emulsion 20 2.0 B2 3.2 D1 25 A3 sl. off white emulsion 21 2.0 B2 3.2 D1 5 A3 sl. off white emulsion 22 2.0 B2 3.2 D1 25 A4 sl. off white emulsion 23 2.0 B2 3.2 D1 5 A3 sl. off white emulsion 24 2.0 B2 3.2 D1 25 A2 sl. off white emulsion 25 2.0 B2 3.2 D1 25 A6 sl. off white emulsion 26 2.0 B2 3.2 D1 25 A6 sl. off white emulsion 27 2.0 B1 3.2 D1 25 A1 sl. off white emulsion 28 2.0 B5 3.2 D1 25 A1 sl. off white emulsion 29 2.0 B4 3.2 D1 25 A1 sl. off white emulsion 30 2.0 B6 3.2 D1 25 A1 Trace pink emulsion 30a 2.7 B7 5.4 D1 25.0 A1 sl. off white emulsion 30b 1.35 B7 + 1.35 B2 5.4 D1 25.0 A1 sl. off white emulsion 30c 5.4 B2 10.8 D1 25.0 A1 sl. off white emulsion

Example 33

Preparation of a White Ink

(63) In order to obtain 50 g of the ink

(64) 10.0 g Tioxide R-XL (titanium dioxide manufactured by Huntsman) are mixed into

(65) 2.55 g Joncryl 8078 and

(66) 1.55 g Formapol FP383 wax and

(67) 0.1 g Tego Foamex 810 (manufactured by Evonik Tego Chemie GmbH) suspended in

(68) 16.5 g Joncryl 90 and

(69) 2.5 g water to produce a white base ink.

(70) To this base ink the following dispersions are added under stirring:

(71) 11.2 g Dispersion C and

(72) 5.6 g Dispersion D

(73) A trace off white laser active ink is obtained comprising laser active components.

(74) The ink is coated on Tambrite white board (manufactured by Stora Enso) using K-bar 1 with a dry coat weight of about 3 g/m.sup.2. It is then imaged using a 10 W CO.sub.2 laser with the settings intensity 40% and speed 8000 mm/sec to yield a black image of high contrast.

Examples 34 to 39

(75) The compositions of Examples 34 to 39 are produced in the same manner as Example 31, except that different combinations of developer dispersions and colour former dispersions are used in the required amounts to arrive at the compositions shown in Table 2. The amounts of the rest of the ingredients are the same as described in example 31. Stable laser active coating dispersions are obtained in each case.

(76) The following additional abbreviations are used in Table 2:

(77) 2,4-dihydroxydiphenylsulfone (Developer D8, purchased from ABCR GmbH)

(78) 1,1,3-Tri(3-tert-butyl-4-hydroxy-6-methylphenyl)butane (Developer D9 with antioxidant properties, purchased from Aceto Corp)

(79) The above inks are coated on Tambrite white board (manufactured by Stora Enso) using K-bar 1 with a dry coat weight of about 3 g/m.sup.2. They are then imaged using a 10 W CO.sub.2 laser with the settings intensity 40% and speed 8000 mm/sec, except for Example 35 where the laser settings are intensity 20% and speed 4000 mm/sec. Black images of high contrast are produced.

(80) TABLE-US-00002 TABLE 2 Color former content of Developer active in content of active in Aspect No % weight % weight formulation 34 2.75 B7 + 11.0 D1 moderately grey 2.75 B2 emulsion 35 5.5 B4 11.0 D1 sl. off white emulsion 36 5.5 B4 8.8 D8 + sl. off white 2.2 D9 emulsion 37 5.5 B4 11.0 D8 sl. off white emulsion 38 5.5 B4 8.8 D8 + sl. off white 2.2 D9 emulsion 39 5.5 B4 11.0 D8 sl. off white emulsion
Formulation Stability

(81) The compositions of all Examples are stable. Any settling which might occur upon prolonged storage can be easily overcome by the use of a thickening agent, e.g. xanthan gum, or by increasing the amount of highly viscous binders such as Joncryl or Poval 203. Settling of inks is well known and accepted and is normally remedied by simply stirring before use. The compositions described herein, in particular compositions based on 3-dibutylamino-6-methyl-7-anilinofluoran (for example Ciba Pergascript Black 2C) and 3-(N-ethyl-N-p-tolylamino)-6-methyl-7-anilinofluoran (as sold for example under the tradename ETAC by Yamada Chemical Company) do not show discoloration after storage for 1 month at 40 C. and the marking performance of the coated substrates is comparable to the one before storage.

COMPARATIVE EXAMPLES

Comparative Example C1

Research Disclosure IPCOM000166609D

(82) Example 3 of the above research disclosure was repeated. When using a mean particle size of 1.0 m for both the color former dispersion and the developer dispersion (as e.g. used for Example 31 of this invention) a thick ink, not suitable for coating, is obtained. The experiment was repeated using a mean particle size of 1.5 m, whereby a relatively thick but coatable ink is obtained

(83) The composition is as follows:

(84) 30 g 3-dibutylamino-6-methyl-7-anilinofluoran (color former B2)

(85) 60 g N-(p-toluene-sulfonyl)-N-3-(p-toluenesulfonyloxyphenyl)urea (developer D1)

(86) 180 g of a 49% weight acrylic copolymer emulsion Carboset GA-2236 (binder A7)

(87) 30 g water

(88) A dried coating of the above ink has the following composition regarding the actives: Color former B2: 16.8% Developer D1: 33.7% Binder A7: 49.5%

Comparative Example C2

Example 31 of this Invention Reengineered to Comply with Comparative Example C1 in the Ratio of Binder to Color Forming Actives

(89) Example 31 of this invention was reformulated to obtain an ink with a similar ratio of binders to color forming actives. The mean particle size of Dispersions D and C was however changed to 1.5 m to comply with Comparative Example C1. A well coatable ink, slightly thinner compared to Comparative Example C1 is obtained. Using a particle size of 1.0 m for both dispersions also provides a well coatable ink. The ink with dispersions of a particle size of 1.5 m was used for the application comparison with Comparative Example C2.

(90) The composition is as follows:

(91) g Dispersion D (color former B2)

(92) 120 g Dispersion C (developer D1)

(93) 32.2 g Joncryl 678 (32% weight aqueous solution, neutralized with ammonia)

(94) 165.7 g Joncryl 90 (44% aqueous solution)

(95) 27.3 g Formapol FP383 Wax (20% aqueous solution)

(96) A dried coating of the above ink has the following composition regarding the actives: Color former B2: 16.3% Developer D1: 32.7% Joncryl 678 8.3% (incl. the amounts used for the dispersions) Joncryl 90 39.7% Formapol FP383 Wax 3.0%

(97) The total amount of binder (without wax) is 48.0%.

(98) Application of the Coating Compositions on Paper and Polymer Film as Substrates

(99) Evaluation of Coated Substrates

(100) The coated substrates prepared according to the invention are evaluated as described below. The results of the evaluations are summarized in Tables 3 to 6.

(101) The coating compositions of the above Examples 1-30c and 31 are applied by coating bars of adequate dimensions adjusted to the viscosity of the samples onto Xerox paper (coated Cento Copy paper purchased from M-Real, Biberist, Switzerland) respectively polyester film as substrates. After drying, transparent coatings are obtained with coat weights in the range of 3-10 g/m.sup.2. The coatings are then imaged using a CO.sub.2 IR laser (wavelength: 10,600 nm, power: 0.5-4 W, diameter of laser beam: 0.35 mm, marking speed 300-1000 mm/s) to yield black high contrast markings. With energy and marking speed fine tuned according to the nature of the image, well readable images are achieved without producing smoke: e.g. a coating of coat weight 5 g/m.sup.2 on Xerox paper with Example 6 produces no smoke when writing text with the laser energy set at 1 W and the marking speed at 1000 mm/sec, or when writing black circles of 1 cm in diameter by using 0.5 W energy at a marking speed of 1000 m/sec.

(102) The compositions of Examples 31-39 are applied as described in their corresponding description. Imaging of the Examples 31 and 33-39 is carried out with a different CO.sub.2 IR laser (wavelength: 10,600 nm, nominal power 10 W, lense with focal length 150 mm, settings for intensity and speed as indicated in the Examples). Black images of high contrast are achieved without producing smoke.

(103) The results of background stability and image stability for Examples 31 and 33-39 are depicted in Tables 5 resp. 6.

(104) Applications on polyester and polypropylene films show similarly good marking results.

(105) Evaluation of Image and Background Stability

(106) Image and background stability results for selected coated Xerox papers are listed in Tables 3 and 4. Selected coating compositions, a. freshly produced and b. after 28 days storage at 40 C., are coated on Xerox paper and imaged. Image and background stability testing is carried out as outlined below.

(107) The results of background stability and image stability for Examples 31 and 33-39 are depicted in Tables 5 resp. 6.

(108) Image Optical Density

(109) The images are produced with the laser marking device described above using the settings 1 W for the energy and 1000 mm/sec for the line speed. The optical density (o.d.) of the image is measured with a Spectroeye densitometer from Gretag-Macbeth.

(110) Background Stability

(111) The optical density (OD) of the unrecorded portion of the coated substrate is measured with a Spectroeye densitometer from Gretag-Macbeth.

(112) Heat Resistance

(113) After printing, the coated substrate is stored for 24 hours in an oven maintained at 60 C. The optical densities of the recorded and unrecorded portions are then measured with a Spectroeye densitometer from Gretag-Macbeth.

(114) Heat/Humidity Resistance

(115) After printing, the coated substrate is stored for 24 hours in an oven maintained at 40 C. and 90% relative humidity. The optical densities of the recorded and unrecorded portions are then measured with a Spectroeye densitometer from Gretag-Macbeth.

(116) Light Resistance

(117) After printing, the coated substrate is stored for 18 hours in a xenon weatherometer (Atlas Suntester CPS+, 250 W/m.sup.2). The optical densities of the recorded and unrecorded portions are then measured with a Spectroeye densitometer from Gretag-Macbeth.

(118) Oil Resistance

(119) After printing, the coated substrate is gravure printed with cottonseed oil and then stored for 24 hours in an oven maintained at 40 C. The optical density of the recorded portion is then measured with a Spectroeye densitometer from Gretag-Macbeth.

(120) TABLE-US-00003 TABLE 3 Background stability xenon light Before 24 h@40 C./ 18 h@ 24 h 40 C. Example exposure 1 h@80 C. 90% RH 24 h@60 C. 250 W/m.sup.2 cottonseed oil No. CIE white CIE white CIE white CIE white CIE white CIE white 2.sup.1) 114.82 109.78 111.55 105.48 43.72 106.42 2.sup.2) 115.12 105.71 111.86 103.17 42.52 106.77 8.sup.1) 114.93 112.31 115.41 107.73 42.06 107.98 8.sup.2) 113.70 110.73 111.90 107.73 49.40 104.01 13.sup.1) 13.sup.2) 105.26 101.37 102.70 98.20 43.51 93.64 18.sup.1) 123.31 121.41 121.04 117.43 36.45 119.74 18.sup.2) 119.03 115.79 116.50 110.16 32.43 114.23 .sup.1)fresh dispersion .sup.2)dispersion after 28 d storage at 40

(121) TABLE-US-00004 TABLE 4 Image stability cottonseed oil 24 h@40 C./ resistance xenon light 1 h@80 C. 90% RH 24 h@60 C. 24 h@40 C. 18 h@ 250 W/m.sup.2 Example Initial After Initial After Initial After Initial After Initial After No. Density exposure density exposure density exposure density exposure density exposure 2.sup.1) 1.04 0.99 1.03 1.04 1.02 1.01 1.00 0.99 1.04 0.94 2.sup.2) 1.03 1.03 1.04 1.07 1.02 1.02 1.04 1.02 1.04 0.93 8.sup.1) 0.85 0.85 0.86 0.88 0.89 0.90 0.88 0.86 0.86 0.77 8.sup.2) 0.75 0.76 0.74 0.78 0.75 0.77 0.76 0.74 0.74 0.66 13.sup.1) 13.sup.2) 0.74 0.75 0.75 0.76 0.73 0.74 0.75 0.70 0.75 0.75 18.sup.1) 0.65 0.66 0.63 0.65 0.64 0.64 0.64 0.66 0.63 0.56 18.sup.2) 0.62 0.64 0.61 0.64 0.61 0.62 0.60 0.62 0.60 0.56 .sup.1)fresh dispersion .sup.2)dispersion after 28 d storage at 40

(122) TABLE-US-00005 TABLE 5 Background stability 24 h@ xenon light Before 1 h@ 40 C./ 24 h@ 18 h@ Example exposure 80 C. 90% RH 60 C. 250 W/m.sup.2 No. CIE white CIE white CIE white CIE white CIE white 31 84.51 70.98 80.60 73.89 32.30 33 79.90 75.68 79.09 74.54 63.81 34 71.90 70.03 75.67 65.38 30.00 35 91.34 86.02 87.74 85.75 56.27 36 91.68 89.51 87.90 86.32 56.39 37 91.77 90.34 88.37 88.37 55.92 38 88.17 82.68 87.68 80.89 41.80 39 88.85 84.29 87.54 82.10 40.74

(123) TABLE-US-00006 TABLE 6 Image stability cottonseed oil 24 h@40 C./ resistance xenon light 1 h@80 C. 90% RH 24 h@60 C. 24 h@40 C. 18 h@ 250 W/m.sup.2 Example Initial After Initial After Initial After Initial After Initial After No. Density exposure density exposure density exposure density exposure density exposure 31 0.54 0.52 0.62 0.66 0.64 0.64 0.62 0.67 0.60 0.54 33 0.93 0.92 0.94 0.94 0.91 0.90 0.92 0.91 0.91 0.82 34 0.84 0.84 0.81 0.86 0.86 0.85 0.78 0.76 0.78 0.71 35 0.45 0.47 0.39 0.42 0.47 0.46 0.47 0.45 0.55 0.45 36 0.63 0.60 0.65 0.64 0.63 0.57 0.60 0.27 0.61 0.49 37 0.65 0.63 0.66 0.55 0.60 0.50 0.66 0.34 0.67 0.54 38 0.94 0.92 0.76 0.76 0.88 0.82 0.76 0.46 0.80 0.68 39 0.81 0.82 0.88 0.83 0.82 0.72 0.80 0.54 0.96 0.74

Application of the Comparative Examples

(124) Both Comparative Examples are coated on Tambrite white board using K-bar 1 to produce a dry coat weight of about 3 g/m.sup.2. They are imaged using a 10 W CO.sub.2 laser with the settings intensity 40% and speed 8000 mm/sec and intensity 60%; speed 10000 mm/sec to yield a black image of high contrast. Image and background stability are measured. The results of background stability and image stability, respectively, are summarized in Tables 7 and 8.

(125) TABLE-US-00007 TABLE 7 Background stability Compar- 24 h@ xenon light ative Before 1 h@ 40 C./ 24 h@ 18 h@ Example exposure 80 C. 90% RH 60 C. 250 W/m.sup.2 No. CIE white CIE white CIE white CIE white CIE white C1 88.94 80.17 85.96 76.20 47.26 C2 86.72 83.58 85.80 81.95 37.03

(126) TABLE-US-00008 TABLE 8 Image stability cottonseed oil 24 h@40 C./ resistance xenon light 1 h@80 C. 90% RH 24 h@60 C. 24 h@40 C. 18 h@ 250 W/m.sup.2 Example Initial After Initial After Initial After Initial After Initial After No. Density exposure density exposure density exposure density exposure density exposure C1.sup.1) 1.04 0.95 1.15 0.94 1.04 0.94 0.91 0.84 1.00 0.84 C1.sup.2) 1.10 0.96 1.21 0.98 1.06 0.92 0.92 0.80 1.27 1.08 C2.sup.1) 0.86 0.88 0.83 0.87 0.82 0.80 0.82 0.76 0.91 0.78 C2.sup.2) 0.87 0.88 0.88 0.93 0.93 0.91 0.84 0.80 1.00 0.84 .sup.1)laser settings: intensity 40%; speed 8000 mm/sec .sup.2)laser settings: intensity 60%; speed 4000 mm/sec

(127) As can be seen from Tables 7 and 8, the overall performance of the Comparative Example C2 with a binder system according to this invention is better compared to the binder system used in Comparative Example C1. Background stability is distinctly better for Comparative Example C2 under hot storage conditions. Only light fastness expressed in % CIE whiteness remaining after exposure is slightly worse (42.7% versus 53.5%). Image stability is better for Comparative Example C2 under hot storage conditions and light fastness is comparable expressed in % image remaining after exposure (86% versus 84% resp. 84% versus 85%), depending on the laser settings used.