EP0956970A1 - Recording material for ink jet printing - Google Patents

Abstract

Ink-jet printing material contains water-soluble ortho- or para-hydroquinone or trihydroxybenzene compound(s), which are over 10 g/l soluble in water; and no water-insoluble compounds of the phenol, bisphenol, hydroquinone diether and pyrocatechol diether classes, which are less than 1 g/l soluble in water. Ink jet printing material contains water-soluble ortho- or para-hydroquinone or trihydroxybenzene compound(s) of formula (I) or (II), which are over 10 g/l soluble in water; and no water-insoluble compounds of the phenol, bisphenol, hydroquinone diether and pyrocatechol diether classes, which are less than 1 g/l soluble in water; X = oxygen (-O-), imino -(NR-), aminocarbonyl (-NR-CO-), oxycarbonyl (-O-CO-), carbonylamino (-CO-NR-), carboxy (-COO-) or a substituted imino, aminocarbonyl or carbonylamino group of the formulae N-Ln-Y, -N(CO)-Ln-Y or -CON-Ln-Y; Y = hydroxy (-OH), -carboxyl (-COOM) or sulfo (-SO3M); Z = alkyl, alkoxy, alkylcarbonyl, alkoxycarbonylamino, alkylcarbonyloxy, alkylsulfonyl, alkylamino, dialkylamino, alkoxycarbonyl or alkylaminocarbonyl with 1-4C alkyl or alkoxy group(s); L = optionally substituted 1-6C alkylene; R = H or 1-4C alkyl; M = H, ammonium (NR4<+>) or a metal atom; m, n = 0 or 1; o = 1 or 2; p = 0, 1, 2 or 3; or o optionally = 0 if Z is methyl or methoxy, and p = 0 or 1.

Description

The invention relates to a recording material for inkjet printing, the contains a new, significantly improved dye stabilizer.

Inkjet printing is a printing process that is done by electrical Signals can be controlled. This creates a fine jet of ink droplets sprayed through a nozzle onto the recording material (ink-jet method).

Arrange at least one nozzle each with yellow, purple or blue-green ink side by side, good quality color reproductions can be achieved.

The ink is mostly an aqueous solution of a dye. The recording material should absorb the dye of the ink quickly and permanently. Most used specially prepared papers or plastic foils with a dye-binding agent Layer are provided. Because of the fineness of the nozzles, pigments rarely used, but mainly dyes in the medium of the inkjet are completely solved. However, these dyes generally have one less lightfastness than the color pigments common in conventional printing inks. As a result, the records made in ink jet printing can only be stored under the influence of light. When stored under light for a long time they start to fade or change color.

To solve this problem, it has already been proposed (US-A-4,256,493) add a water-soluble UV absorber to the ink. By reacting with the Dye can precipitate solid particles in the ink that clog the fine nozzle. One has therefore already gone the other way and put the recording material Dye stabilizers too. So in GB-A-2 088 777 the Use of water-insoluble sterically hindered phenols, if necessary in combination with UV absorbers of the benzotriazole type, proposed. EP-A-373 573 describes the use of water-soluble dialkoxybenzene derivatives and DE 43 37 862 the use of water-soluble, sulfonated phenols and bisphenols. More connections can be found e.g. in EP 280 650, EP 304 316, EP 685 345, EP 584 147 and Research Disclosure 24239 (1984).

The dye stabilizers or stabilizer combinations used hitherto are insufficient in effect.

The object of the invention was therefore to further improve the protection of recording materials for inkjet printing under the influence of light. This task is solved by using certain connections.

worin

X

-O-, -NR-,

-NR-CO-, -O-CO-, -CO-NR-, -COO-,

Y

-OH, -COOM oder -SO₃M,

Z

Alkyl, Alkoxy, Alkylcarbonyl, Alkylcarbonylamino, Alkylcarbonyloxy, Alkylsulfonyl, Alkylamino, Dialkylamino, Alkoxycarbonyl oder Alkylaminocarbonyl,

L

gegebenenfalls substituiertes Alkylen mit 1 bis 6 Kohlenstoffatomen,

R

Wasserstoff oder Alkyl mit 1 bis 4 Kohlenstoffatomen,

M

Wasserstoff, NR₄ ^⊕ oder ein Metallatom,

m, n

0 oder 1,

o

0, 1 oder 2 und

p

0, 1, 2 oder 3 bedeuten,

wobei gilt, daß ein durch Z dargestellter oder darin enthaltener Alkyl- oder Alkoxyrest 1 bis 4 Kohlenstoffatome aufweist und o nur dann 0 ist, wenn Z Methyl oder Methoxy bedeutet und p 0 oder 1 ist und wobei gilt, daß wasserlösliche Verbindungen sich zu mehr als 10 g/l und wasserunlösliche Verbindungen sich zu weniger als 1 g/l lösen.The invention therefore relates to a recording material for inkjet printing, characterized in that it contains at least one water-soluble compound of the formula I or II and does not contain a water-insoluble compound from the class of the phenols, bisphenols, hydroquinone diethers and pyrocatechol diethers:

wherein

X

-O-, -NR-,

-NR-CO-, -O-CO-, -CO-NR-, -COO-,

Y

-OH, -COOM or -SO ₃ M,

Z.

Alkyl, alkoxy, alkylcarbonyl, alkylcarbonylamino, alkylcarbonyloxy, alkylsulfonyl, alkylamino, dialkylamino, alkoxycarbonyl or alkylaminocarbonyl,

L

optionally substituted alkylene with 1 to 6 carbon atoms,

R

Hydrogen or alkyl having 1 to 4 carbon atoms,

M

Hydrogen, NR ₄ ^⊕ or a metal atom,

m, n

0 or 1,

O

0, 1 or 2 and

p

0, 1, 2 or 3 mean

with the proviso that an alkyl or alkoxy radical represented by Z or contained therein has 1 to 4 carbon atoms and o is only 0 if Z is methyl or methoxy and p is 0 or 1 and it is true that water-soluble compounds combine to form more than 10 g / l and water-insoluble compounds dissolve to less than 1 g / l.

X

-NR-,

-NR-CO-, -CO-NR- oder -COO-,

Z

Alkyl mit 1 bis 4 Kohlenstoffatomen,

L

gegebenenfalls substituiertes Alkylen mit 1 bis 4 Kohlenstoffatomen und

p

0 oder 1.

In a preferred embodiment of the invention mean

X

-NO-,

-NR-CO-, -CO-NR- or -COO-,

Z.

Alkyl with 1 to 4 carbon atoms,

L

optionally substituted alkylene of 1 to 4 carbon atoms and

p

0 or 1.

Examples of particularly suitable compounds according to the invention are:

The compounds of the formulas I and II are usually used in an amount of 10 to 3,000 mg / m ^{2 of} recording material. Preferably 50 to 1,500 mg / m ^{2 of} recording material are used.

The ink jet printing process is known. Details of the technology are, for example in the chapter "Ink Jet Printing" by R.W. Kenyon in "Chemistry and Technology of Printing and Imaging Systems ", publisher Peter Gregory, Blackie Academic & Professional, Chapmann & Hall 1996, pages 113 to 138, and the one therein literature cited.

With the recording material according to the invention it does not matter which one The type of ink and the dye dissolved in it. Usually watery Inks used. A selection of particularly suitable inks is in EP-A-672 538 disclosed on pages 3 to 6.

The recording materials for inkjet printing consist of a support with an ink jet printable surface. The carrier is usually Paper or plastic wrap and is usually on at least one side coated with a material that is particularly receptive to inks.

The carrier preferably has a thickness of 80 to 250 microns; in the case of polyolefin laminated Paper has a thickness of 80 to 220 µm in particular, the polyolefin layers in particular a thickness of 5 to 30 microns. Polyethylene is preferred as the polyolefin.

The material can e.g. by means of a cascade or curtain caster, as used by the Production of photographic silver halide materials is known, starting from Backing material and a casting solution for each layer to be applied in one Passage can be established.

The individual layers have a dry layer thickness of 0.1 to 20 μm, preferably from 0.5 to 5 µm.

In a preferred embodiment of the invention the recording material has on at least one side of the support at least two layers with the connections of formulas I or II can be contained in one or more layers can.

After pouring the casting solution (s) onto the support, the material is dried and is then ready to use.

In a further preferred embodiment of the invention, the recording material contains in at least one layer an agent containing the dyes of the ink binds diffusion and smudge-proof.

Suitable agents that bind the dyes diffusion and smudge-proof are e.g. cationic Pickling, dye-complexing compounds and aluminum hydroxide.

Cationic pickling is preferred because azo dyes are usually used as dyes can be used with acidic groups.

Suitable cationic mordants are e.g. Compounds from the classes of polyvinylpyridines, optionally quaternized, the polyvinylimidazoles, if appropriate quaternized, the poly (-di) allylammonium compounds, the polydialkylaminoalkyl (meth) acrylates, optionally quaternized, the polydialkylammoniumalkyl (meth -) - acrylamide, optionally quaternized, the polyvinylbenzyldi or trialkylammonium compounds, the polyester with quaternary ammonium groups, the polyamides with quaternary ammonium groups, the polyurethane with quaternary ammonium groups and the polymers of N, N, N-trialkyl-N- (meth -) - acrylamidobenzylammoniumverbindungen.

The cationic mordants can be water-soluble or water-dispersible. The cationic mordants have a weight average molecular weight of preferably at least 2,000, especially at least 20,000.

Compounds containing phosphonium groups (EP-A-609 930) are used as well as ground cationic ion exchange resins finely divided into the pickling layer.

The agents which bind the dyes in a diffusion-resistant and smudge-proof manner are usually used in an amount of 10 to 3,000 mg / m ² , preferably 50 to 1,000 mg / m ² , of recording material.

Suitable binders for the applied layers are described in EP-A-672 538 pages 6 and 7. Gelatin is preferred.

In a preferred embodiment, the recording material contains spacers. The spacers are in particular spherical, have a medium one Diameters from 1 to 50 microns, especially from 5 to 20 microns and have a narrow Grain size distribution. Suitable spacers are in DE-A-2 424 893, DE-A-3 331 542 and Research Disclosure 307 105, chap. XVI (1989). The spacers are water-insoluble and resistant to those used in the inks Solvent additives. Examples of suitable polymers are crosslinked or uncrosslinked Polymethyl methacrylate, polystyrene, styrene-divinylbenzene copolymer and cross-linked or uncross-linked polyvinyltoluene.

In a further embodiment of the invention, the material contains agents which improve the optical properties of the material, preferably optical brighteners. Suitable compounds are in Research Disclosure 37 254, Part 8 (1995), p. 292 ff. and in Research Disclosure 38 957, Part VI (1996), p. 607 ff. This Means are preferably in a layer below the farthest from the support removed layer, particularly preferably in a layer below the receiving layer brought in.

The layers of the recording material can be hardened, i.e. the one used The binder is crosslinked using suitable chemical processes. Suitable Hardening agents are in Research Disclosure 37 254, Part 9 (1995), page 294, in Research Disclosure 37 038, Part XII (1995), page 86 and in Research Disclosure 38 957, Part II B (1996), page 599.

Examples of particularly suitable curing agents are:

The curing agent is usually 0.005 to 10 wt .-%, based on the curable Binder used. 0.01 to 1% by weight is preferably used.

example 1

A recording material for ink jet printing was produced by applying the following layers in the order given to a support made of paper coated with polyethylene (thickness: 200 μm). The quantities given relate to 1 m ² .

Sample 1

Layer 1:

1.0 g gelatin
0.1 g white toner WT-1
0.15 g polyvinylpyrrolidone (M _W ~ 120,000)
0.2 g emulsifier E-1

Layer 2:

4.0 g gelatin
0.2 g stain B-1
0.4 g emulsifier E-1

Layer 3:

0.5 g gelatin
0.5 g phthaloyl gelatin
1 mg hardener H-2
0.2 g emulsifier E-1

Samples 2 to 6

Samples 2 to 6 were produced in the same way as sample 1, with the difference that the compounds listed in Table 1 were added to layer 2 in an amount of 1.5 g / m ² .

Compounds used in the samples:

The dried samples are printed on an HP 870 CXi printer with the three primary colors blue-green, purple and yellow and then irradiated with the light of a 100 kLx xenon lamp normalized to daylight (dose: 10 · 10 ⁶ Lxh) and the percentage density decrease is measured . The results are shown in Table 1. (V: comparison, E: invention) sample additive Δ color density (%) blue green purple yellow 1 (V) - -36 -44 -28 2 (E) I-2 -30 -36 -15 3 (E) I-3 -18 -25 -13 4 (E) I-4 -29 -30 -20 5 (E) I-7 -19 -29 -16 6 (E) II-1 -24 -28 -19

As Table 1 shows, the compounds according to the invention improve the stability of the dyes clearly.

Example 2

A recording material for ink jet printing was produced by applying the following layers in the order given to a support made of paper coated with polyethylene (thickness: 180 μm). The quantities given relate to 1 m ² .

Sample 7

Layer 1:

6.0 g gelatin
0.3 g stain B-1
0.4 g emulsifier E-1

Layer 2:

0.5 g gelatin
0.5 g phthaloyl gelatin
0.01 g stain B-1
0.2 g emulsifier E-1

Samples 8 to 10

Samples 8 to 10 were prepared like Sample 7, with the difference that the compounds listed in Table 2 were added to Layer 1. sample Addition in layer 1 [g / m ² ] 8th V-1 (1.2), V-2 (0.36), V-3 (0.2), CPM (0.74) 9 V-3 (1.5), CPM (1.0) 10th I-7 (1.5)

The dried samples are printed on an HP 870 CXi printer with the three primary colors blue-green, purple and yellow and then irradiated with the light of a 100 kLx xenon lamp normalized to daylight (dose: 4 · 10 ⁶ Lxh) and the percentage density decrease is measured . The results are shown in Table 3. (V: comparison, E: invention) sample Δ color density (%) blue green purple yellow 7 (V) -17 -36 -11 8 (V) -15 -33 -13 9 (V) -19 -34 -13 10 (E) -11 -10 -9

As Table 3 shows, a combination of the comparison compounds V-1, V-2 and V-3 according to GB-A-2 088 777 hardly improves the stability of the material. Just adding the water-insoluble hydroquinone V-3 is just as ineffective. Only the addition of the hydroquinone I-7 according to the invention improves the stability, especially the purple dye.

Compounds used in the examples:

Example 3

A recording material for ink jet printing was produced by applying two layers to a substrate made of paper coated on both sides with polyethylene by the curtain coating method. The recipes for the casting solutions are given in Table 4. The samples were dried at 38 ° C. (V = comparison, E = invention) layer Wet film thickness Components Sample 11 (V) Sample 12 (E) 1 (below) 100 µm gelatin 55.2 g 55.2 g Polyvinyl pyrrolidone 27.6 g 27.6 g II-7 - 15.0 g water to 1 l to 1 l 2 (above) 20 µm gelatin 40.0 g 40.0 g Polyvinyl pyrrolidone 22.4 g 22.4 g water to 1 l to 1 l

The dried samples are printed in an Encad Novajet device using the basic colors of the GA printing inks. Color density is measured with a McBeth TR 1224 density meter. The samples are then irradiated for 48 hours with the light of a 100 kLx xenon lamp normalized to daylight and the residual density is determined (Table 5). (V = comparison, E = invention) colour Residual density (%) Sample 11 (V) Sample 12 (E) blue green 72 92 purple 11 87 yellow 97 95 black 60 86

As Table 5 shows, the compound II-7 according to the invention is a very effective one Dye stabilizer.

Claims (3)

Recording material for inkjet printing, characterized in that it contains at least one water-soluble compound of the formula I or II and that it does not contain a water-insoluble compound from the class of the phenols, bisphenols, hydroquinone diethers and pyrocatechol diethers:

wherein

X

-O-, -NR-,

-NR-CO-, -O-CO-, -CO-NR-, -COO-,

Y

-OH, -COOM or -SO ₃ M,

Z.

Alkyl, alkoxy, alkylcarbonyl, alkylcarbonylamino, alkylcarbonyloxy, alkylsulfonyl, alkylamino, dialkylamino, alkoxycarbonyl or alkylaminocarbonyl,

L

optionally substituted alkylene with 1 to 6 carbon atoms,

R

Hydrogen or alkyl having 1 to 4 carbon atoms,

M

Hydrogen, NR ₄ ^⊕ or a metal atom,

m, n

0 or 1,

O

0, 1 or 2 and

p

0, 1, 2 or 3 mean

with the proviso that an alkoxy or alkyl radical represented by Z or contained therein has 1 to 4 carbon atoms and o is only 0 when Z is methyl or methoxy and p is 0 or 1 and it is true that water-soluble compounds combine to form more than 10 g / l and water-insoluble compounds dissolve to less than 1 g / l. Recording material according to claim 1, characterized in that in the compounds of formula I or II

X

-NO-,

-NR-CO-, -CO-NR- or -COO-,

Z.

Alkyl with 1 to 4 carbon atoms,

L

optionally substituted alkylene of 1 to 4 carbon atoms and

p

0 or 1 mean.

Recording material according to claim 1, characterized in that the compounds of formula I or II are contained in the recording material in an amount of 50 to 1,500 mg / m ² .