Ink jet recording process using certain benzotriazole derivatives as light stabilizers

UV-absorbers of the formula I ##STR1## in which n is 1 to 4, R is H, C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.8 cycloalkyl, phenyl or C.sub.7 -C.sub.9 phenylalkyl, R.sup.1 is H, Cl, C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy and R.sup.2 is an n-valent hydrophilic group, are especially suitable for the light stabilization of ink-jet prints. The compound of the formula I is here added to the recording material, preferably in a surface coating. Such compounds have the further advantage that they form particularly stable emulsions.

The invention relates to the use of certain UV absorbers of the type of 
2-(2-hydroxyphenyl)-benzotriazoles as light stabilizers for recording 
materials for ink-jet printing, and to the recording materials stabilized 
against light-induced damage by means of these compounds. 
Printing by means of an ink jet is a very rapid printing process, which can 
be controlled by electrical signals. In this case, a fine jet of ink 
droplets is sprayed through a nozzle onto the recording material. The ink 
is a solution of a dye in an aqueous or non-aqueous solvent. The recording 
material should rapidly and durably absorb the dye from the ink. In most 
cases, specially prepared papers or plastic sheets are used for this 
purpose, which are coated with a dye-binding layer. Because of the 
fineness of the nozzles, pigments are hardly used, but predominantly dyes 
which are fully dissolved in the ink jet medium. However, these dyes 
generally have a lower light fastness than the colour pigments usual in 
conventional printing inks. Consequently, recordings made by ink-jet 
printing have only a limited storage life in the presence of light. In the 
case of prolonged storage in light, they start to fade or to discolour. 
In order to solve this problem, it has already been proposed (U.S. Pat. No. 
4,256,493) to add a water-soluble UV absorber to the ink. By interaction 
with the dye, solid particles can then precipitate in the ink, which block 
the fine nozzle. A different approach has therefore been taken, by adding 
light stabilizers to the recording material. Thus, in GB-A No. 2,088,777, 
an addition of UV absorbers of the benzotriazole type in combination with 
sterically hindered phenols is proposed as a measure against bleaching of 
the dyes. These additives are admixed in the dissolved form to a coating 
composition of colourless fillers, a binder and a dye receptor or mordant, 
this composition being applied to one side of the recording material 
(paper in most cases). The light stabilization of hard-copy prints, 
including ink-jet prints, by the addition of UV absorbers of various types 
to the recording material has been described in Research Disclosure No. 
24,239 (1984, 284). 
It has now been found that certain UV absorbers of the benzotriazole type 
are particularly suitable for this purpose. These are compounds of the 
formula I 
##STR2## 
in which n is 1 to 4, R is hydrogen, C.sub.1 -C.sub.12 alkyl, C.sub.5 
-C.sub.8 cycloalkyl, phenyl or C.sub.7 -C.sub.9 phenylalkyl, R.sup.1 is 
hydrogen, chlorine, C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy and, 
in the case of n=1, is also --COOR.sup.3, R.sup.2 (a) in the case of n=1, 
is an --OR.sup.3 or NR.sup.4 R.sup.5 group, (b) in the case of n=2, is a 
divalent --O--R.sup.6 --O--, --O--R.sup.6 --N(R.sup.7)--, 
--N(R.sup.7)--R.sup.8 --N(R.sup.7)-- group or 
##STR3## 
(c) in the case of n=3, is a trivalent 
##STR4## 
or --N(R.sup.7)-- 
##STR5## 
group and (d) in the case of n=4, is a tetravalent 
##STR6## 
or --N(R.sup.7)-- 
##STR7## 
group, in which R.sup.3 is hydrogen, C.sub.1 -C.sub.18 alkyl, which is 
monosubstituted or polysubstituted by --OH or --O--COR.sup.10, C.sub.3 
-C.sub.30 alkyl which is interrupted by one or more --O-- or 
--N(R.sup.7)-- and can be monosubstituted or polysubstituted by --OH or 
--O--COR10 groups, unsubstituted or OH-substituted C.sub.5 -C.sub.12 
cycloalkyl, unsubstituted or OH-substituted C.sub.2 -C.sub.18 alkenyl, 
C.sub.7 -C.sub.15 -phenylalkyl or C.sub.7 -C.sub.15 alkylphenylalkyl, 
glycidyl, furfuryl or a glycosyl group, R.sup.4 and R.sup.5 independently 
of one another are hydrogen, C.sub.1 -C.sub.18 alkyl, C.sub.1 -C.sub.4 
hydroxyalkyl, C.sub.3 -C.sub.30 alkyl which is interrupted by --O-- or 
--N(R.sup.7)--, C.sub.5 -C.sub.12 cycloalkyl, phenyl which is 
unsubstituted or substituted by hydroxyl, C.sub.1 -C.sub.4 -alkoxy or 
halogen, C.sub.3 -C.sub.8 alkenyl, C.sub.7 -C.sub.15 phenylalkyl or 
C.sub.7 -C.sub.15 alkylphenylalkyl, or R.sup.4 and R.sup.5, together with 
the N atom, form a pyrrolidine, piperidine, piperazine or morpholine ring, 
R.sup.6 is C.sub.2 -C.sub.8 alkenylene, C.sub.4 -C.sub.8 alkenylene, 
C.sub.4 alkynylene, cyclohexylene, C.sub.4 -C.sub.30 alkylene which is 
interrupted by one or more --O-- or --N(R.sup.7)--, or a group --CH.sub.2 
--CH(OH)--CH.sub.2 --O--R.sup.9 -- O--CH.sub.2 --CH(OH)--CH.sub.2 -- or 
##STR8## 
R.sup.7 is hydrogen or C.sub.1 -C.sub.18 alkyl, R.sup.8 is C.sub.2 
-C.sub.12 alkylene which can be interrupted by one or more --O--, R.sup.9 
is C.sub.2 -C.sub.8 alkylene, C.sub.4 -C.sub.10 alkylene which is 
interrupted by one or more --O--, cyclohexylene, phenylene or a group 
##STR9## 
R.sup.10 is C.sub.1 -C.sub.18 alkyl or phenyl, R.sup.11 is C.sub.3 
-C.sub.10 alkanetriyl and R.sup.12 is C.sub.4 -C.sub.12 alkanetetrayl. 
Some of the compounds of the formula I have been described in EP-A No. 
57,160 as stabilizers for organic materials, for example polymers, surface 
coatings or photographic materials. The preparation of these compounds is 
also described therein. Inasmuch as the compounds are novel, they can be 
prepared analogously thereto. In Research Disclosure No. 22,519 (1983 [1], 
6), the use of such benzotriazoles as light stabilizers for reproduction 
materials and for the dyes contained therein is proposed. The use in inks 
is also mentioned there. A use in recording materials for ink-jet printing 
is not mentioned therein. 
C.sub.1 -C.sub.12 Alkyl R can, for example, be methyl, ethyl, isopropyl, 
n-butyl, tert-butyl, sec-butyl, tert-pentyl, sec-pentyl, n-hexyl, 
sec-hexyl, n-octyl, ditert-octyl, sec-decyl or n-dodecyl. Cycloalkyl R can 
especially be cyclohexyl. Phenylalkyl R can especially be 
.alpha.,.alpha.-dimethyl-benzyl. Preferably, R is a branched alkyl 
radical, especially tert-butyl. 
C.sub.1 -C.sub.4 Alkyl or C.sub.1 -C.sub.4 alkoxy R.sup.1 can, for example, 
be methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, methoxy, ethoxy, 
isopropoxy, butoxy or tert-butoxy. 
C.sub.1 -C.sub.18 Alkyl R.sup.4, R.sup.5, R.sup.7 and R.sup.10 can be 
unbranched or branched alkyl, for example methyl, ethyl, propyl, 
isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, 
n-hexyl, 2-ethylbutyl, n-octyl, isooctyl, 2-ethylhexyl, 
1,1,3,3-tetraethylbutyl, n-decyl, isodecyl, n-dodecyl, 
1,1,7,7-tetramethyloctyl, n-tetradecyl or n-octadecyl. 
Alkyl R.sup.3 which is substituted by --OH or --OCOR.sup.10 can, for 
example, be 2-hydroxyethyl, 2-hydroxypropyl, 2-hydroxylbutyl, 
3-hydroxybutyl, 2,3-dihydroxypropyl, 2,2-di-(hydroxymethyl)-propyl, 
4-hydroxybutyl, 6-hydroxyhexyl, 8-hydroxyoctyl, 2-acetoxyethyl, 
2-propionyloxyethyl, 2-octanoyloxypropyl, 2,3-diacetyloxypropyl or 
4-acetoxybutyl. 
C.sub.3 -C.sub.30 Alkyl R.sup.3, R.sup.4 and R.sup.5 which is interrupted 
by --O-- or --N(R.sup.7)-- can, for example, be 2-methoxyethyl, 
2-ethoxyethyl, 2-butoxyethyl, 2-isopropoxyethyl, 2-octyloxyethyl, 
3,6-dioxaheptyl, 3,6,9-trioxaundecyl, 3,6,9,12-tetraoxatridecyl, 
5-hydroxy-3-oxapentyl or 11-hydroxy-3,6,9-trioxaundecyl. In particular, 
R.sup.3 is a radical --CH.sub.2 CH.sub.2 O.sub.m CH.sub.3 with m=2-10. 
C.sub.1 -C.sub.4 Hydroxyalkyl R.sup.4 and R.sup.5 can, for example, be 
hydroxymethyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl or 
2-hydroxybutyl. 
C.sub.5 -C.sub.12 Cycloalkyl R.sup.4 and R.sup.5 can, for example, be 
cyclopentyl, cyclohexyl, methylcyclohexyl, cyclooctyl or cyclododecyl. 
R.sup.3 can also be OH-substituted cycloalkyl, for example 
4-hydroxycyclohexyl. 
C.sub.2 -C.sub.18 Alkenyl R.sup.3 which can be substituted by OH can, for 
example, be vinyl, allyl, methallyl, 2-buten-1-yl, oleyl or 
4-hydroxy-2-buten-1-yl. C.sub.3 -C.sub.8 Alkenyl R.sup.4 and R.sup.5 can 
especially be allyl. 
C.sub.7 -C.sub.15 Phenylalkyl or C.sub.7 -C.sub.15 alkylphenylalkyl 
R.sup.3, R.sup.4 and R.sup.5 can, for example, be benzyl, 2-phenylethyl, 
1-phenylethyl, 3-phenylpropyl, 2-phenylprop-2-yl, 4-methylbenzyl or 
4-octylbenzyl. 
Phenyl R.sup.4 and R.sup.5 which is substituted by alkyl, alkoxy or halogen 
can, for example, be 4-tolyl, 4-isopropylphenyl, 3-methoxyphenyl, 
4-ethoxyphenyl, 4-fluorophenyl or 4-chlorophenyl. 
C.sub.2 -C.sub.8 Alkylene R.sup.6 and R.sup.9 can be branched or 
straight-chain alkylene, for example 1,2-ethylene, tri-, tetra-, penta-, 
hexa- or octamethylene, 2,2-dimethyl-1,3-propylene, 1,2-propylene or 
1,2-butylene. In addition, C.sub.2 -C.sub.12 alkylene R.sup.8 can also, 
for example, be decamethylene or dodecamethylene. 
Alkenylene or alkynylene R.sup.6 can, for example, be 1,4-but-2-enylene, 
1,4-but-2-inylene or 2-methyl-1,4-but-2-enylene. 
Alkylene R.sup.6 and R.sup.9 which is interrupted by --O-- or 
--N(R.sup.7)-- can, for example, be 3-oxa-1,5-pentylene, 
3,6-dioxa-1,8-octylene, 3,6,9-trioxa-1,11-undecylene, 
3-methylaza-1,5-pentylene or 3,9-dioxa-5-methylaza-1, 11-undecylene. 
R.sup.6 is especially a radical --CH.sub.2 CH.sub.2 O.sub.m CH.sub.2 
CH.sub.2 -- with m=1-6. 
An alkanetriyl radical R.sup.11 can, for example, be propane-1,2,3-triyl or 
a CH.sub.3 C(CH.sub.2 --).sub.3 or C.sub.2 H.sub.5 C(CH.sub.2 --).sub.3 
radical. 
An alkanetetrayl radical R.sup.12 can, for example, be 
butane-1,2,3,4-tetrayl or a C(CH.sub.2 --).sub.4 radical. 
Those compounds of the formula I are preferably used in which n is 1 or 2, 
R is C.sub.1 -C.sub.4 alkyl, R.sup.1 is hydrogen, chlorine or methoxy, 
R.sup.2 is (a) an --OR.sup.3 or --NR.sup.4 R.sup.5 group in the case of 
n=1 or (b) an --O--R.sup.6 --O-- group in the case of n=2, R.sup.3 being 
hydrogen, C.sub.1 -C.sub.18 alkyl which is substituted by 1 to 3 OH 
groups, C.sub.3 -C.sub.18 alkyl which is interrupted by one or more --O-- 
and can be substituted by one or more --OH, cyclohexyl or allyl, R.sup.4 
and R.sup.5 independently of one another are C.sub.1 -C.sub.12 alkyl, 
C.sub.2 -C.sub.4 hydroxyalkyl or C.sub.3 -C.sub.12 alkoxyalkyl or R.sup.4 
and R.sup.5, together with the N atom, form a pyrrolidine, piperidine, 
piperazine or morpholine ring, R.sup.6 is C.sub.2 -C.sub.6 alkylene, 
C.sub.4 -C.sub.14 -alkylene which is interrupted by one or more --O-- or a 
-- CH.sub.2 --CH(OH)--CH.sub.2 --O--R.sup.9 --O--CH.sub.2 
--CH(OH)--CH.sub.2 -- group and R.sup.9 is C.sub.2 -C.sub.4 -alkylene or 
C.sub.4 -C.sub.8 alkylene which is interrupted by one or more --O--. 
Amongst these, those compounds of the formula I are preferred in which R is 
tert-butyl. 
Depending on the definition of R.sup.2, the compounds of the formula I are 
carboxylic acids, carboxylic acid esters or carboxylic acid amides. The 
esters are particularly suitable, especially the compounds of the formula 
I in which n is 1 or 2 and R.sup.2 is an --OR.sup.3 or --O--R.sup.6 --O-- 
group. 
With particular preference, those compounds of the formula I are used in 
which n is 1 or 2, R.sup.1 is hydrogen, chlorine or methoxy, R.sup.2 is 
(a) a group of the formula 
##STR10## 
in which u is 1-9, v is 1-6 and w is 1-6, in the case of n=1 and (b) a 
group of the formula 
##STR11## 
in which x is 1-7 and y is 1-4, in the case of n=2. 
Those compounds of the formula I are also preferred in which n is 1, 
R.sup.1 is --COOR.sup.3 and R.sup.2 is --OR.sup.3. 
Preferably, those compounds of the formula I are used which are liquid at 
room temperature. 
Examples of individual compounds of the formula I are the compounds of the 
following formulae: 
##STR12## 
Mixtures of a plurality of compounds of the formula I are frequently 
obtained in the preparation of these compounds. For example, the monoester 
can be formed in addition to the diester in the esterification of a diol. 
Polyalkylene glycols are frequently technical mixtures of varying degrees 
of oxyalkylation. When these are used as the diols, corresponding mixtures 
of compounds of the formula I are obtained. Such mixtures are equally 
suitable for the use according to the invention as homogeneous compounds. 
Since such mixtures are in most cases liquid, they can even be of 
particular advantage. 
Examples of these are the compounds (8), (20), (21), (23), (28), (34), (47) 
and (51) listed above, or mixtures of (3) and (24), of (19) and (29), of 
(33) and (46) or of (5), (26), (33) and (46). 
Novel compounds and, as such, also the subject of the invention are the 
compounds of the formula II, 
##STR13## 
in which R and R.sup.3 are as defined above. 
As compared with the benzotriazole-type UV absorbers proposed in Research 
Disclosure No. 24,239, the benzotriazoles used according to the invention 
are distinguished by an enhanced hydrophilic character. However, it was 
not to be expected that hydrophilic UV absorbers would be particularly 
suitable as light stabilizers for ink-jet printing recording materials. As 
is known, the effect of the UV absorbers is based on the fact that 
short-wave light (200-400 nm) is filtered out, and this effect should 
depend only on the wavelengths region of the light absorption of the 
molecule, but be independent of other properties of the molecule. To this 
extent, the high effectiveness of the UV absorbers according to the 
invention was surprising. 
Moreover, the compounds of the formula I are readily dispersible. In 
combination with suitable surfactants, they give very stable oil-in-water 
emulsions of very small droplet diameter. It has also been found that such 
emulsions according to the invention do not agglomerate on drying out, so 
that the UV absorber is in a very homogeneous distribution on the 
recording material, whereas corresponding emulsions or dispersions 
containing the UV absorbers indicated in Research Disclosure No. 24,239 
tend to an agglomeration of the UV absorber on drying out. 
The recording material is a two-dimensional sheet-like structure which can 
consist of one or more layers. The carrier layer usually consists of paper 
or a plastic film or of a laminate of such materials. The carrier layer 
can be coated, on one side or on both sides, with a material which is 
particularly receptive for the ink dyes. The recording material can be 
transparent, for example in the case of projection films. In most cases, 
however, the recording material is not transparent and is read in 
reflected light. 
The UV absorber according to the invention can be incorporated in the 
carrier material as early as the production of the latter, for example 
during the production of paper by addition to the paper pulp, or during 
the production of plastic films by addition to the polymer before 
extrusion. A second application method is spraying of the carrier material 
with a solution of the UV absorber in a highly volatile solvent. 
In most cases, however, a layer having an affinity for dyes is applied to 
the carrier material and, in this case, the UV absorbers according to the 
invention are added to the coating composition. These coating compositions 
usually consist of a solid filler and a binder as well as minor 
proportions of additives. 
The filler is quantitatively the main constitutent of the coating 
composition. Examples of conventional fillers are lime, chalk, silica, 
kaolin, talc, clay, Ca, Mg or Al silicates, gypsum, barite, zeolite, 
bentonite, diatomaceous earth, vermiculite, titanium dioxide, zinc oxide, 
magnesium oxide, magnesium carbonate, starch or the surface-modified 
silica described in JP-A No. 85/260,377. 
The binder binds the filler within itself and to the carrier material. It 
can be used as an aqueous solution, organic solution or aqueous 
dispersion. Examples of usual binders are polyvinyl alcohol, partially 
hydrolysed polyvinyl acetate, cellulose ethers, polyvinylpyrrolidone and 
copolymers thereof, polyethylene oxide, salts of polyacrylic acid, sodium 
alginate, oxidized starch, gelatine, casein, vegetable gum, dextrin, 
albumin, dispersions of polyacrylates or acrylate/methacrylate copolymers, 
latices of natural or synthetic rubber, poly(meth)acrylamide, polyvinyl 
ethers, polyvinyl esters, copolymers of maleic acid, melamine resins, urea 
resins, or chemically modified polyvinyl alcohols, as described in JP-A 
No. 86/134,290 or 86/134,291. 
A dye receptor or mordant, which fixes the dye more firmly to the coating, 
can be added to the binder. Dye receptors for acid dyes are of cationic or 
amphoteric nature. Examples of cationic receptors are polymeric ammonium 
compounds, for example polyvinylbenzyl-trimethylammonium chloride, 
polydiallyl-dimethylammonium chloride, 
polymethacryloxyethyl-dimethyl-hydroxyethylammonium chloride, 
polyvinylbenzylmethylimidazolium chloride, polyvinylbenzyl-picolinium 
chloride or polyvinylbenzyl-tributylammonium chloride. Further examples 
are basic polymers, such as poly-(dimethylaminoethyl methacrylate), 
polyalkylenepolyamines and condensation products thereof with 
dicyandiamide, amine/epichlorohydrin polycondensates or the compounds 
described in JP-A No. 82/36,692, 82/64,591, 82/187,289, 82/191,084, 
83/177,390, 83/208,357, 84/20,696, 84/33,176, 84/96,987, 84/198,188, 
85/49,990, 85/71,796, 85/72,785, 85/161,188, 85/187,582, 85/189,481, 
85/189,482, 86/14,979, 86/43,593, 86/57,379, 86/57,380, 86/58,788, 
86/61,887, 86/63,477, 86/72,581, 86/95,977 and 86/134,291 or in U.S. Pat. 
Nos. 4,547,405 and 4,554,181 and also in DE-A-3,417,582. Gelatine is an 
example of amphoteric dye receptors. 
The dye-binding coating can contain a number of further additives, for 
example antioxidants, light stabilizers (also including UV absorbers which 
are not UV absorbers according to the invention), viscosity improvers, 
fluorescent brighteners, biocides or/and antistatics. 
Examples of suitable antioxidants are, in particular, sterically hindered 
phenols and hydroquinones, for example the antioxidants listed in GB-A No. 
2,088,777 or in JP-A Nos. 85/72,785, 85/72,786 and 85/71,796. 
Examples of suitable light stabilizers are, in particular, organic nickel 
compounds and sterically hindered amines, for example the light 
stabilizers mentioned in JP-A Nos. 83/152,072, 86/146,591, 86/163,886, 
85/72,785 and 86/146,591 or in GB-A No. 2,088,777, JP-A Nos. 084/169,883 
and 86/177,279. 
If the UV absorber used according to the invention is a liquid, these 
additives can be dissolved directly in the UV absorber. Alternatively, 
they are dissolved in an organic solvent and mixed with the liquid UV 
absorber or with a solution of the UV absorber in an organic solvent. 
Preferably, aqueous coating compounds are used. In this case, the UV 
absorber and the other additives must be dispersed as homogeneously as 
possible in the coating composition. If the UV absorber is liquid, it can, 
after the addition of surfactants, be dispersed directly in the binder or 
in the coating composition. If the UV absorber is solid or viscous, it is 
advisable to dissolve it in an organic solvent and to disperse this 
solution in the coating composition. 
The solvent used is preferably of low volatility, so that the UV absorber 
remains in the liquid state even after prolonged storage of the recording 
material. For preparing the dispersions, however, a volatile auxiliary 
solvent is also added in most cases, and this is removed again during the 
process of producing the recording material. Examples of low-volatility 
solvents are organic liquids of oily character and high boiling point, for 
example phthalates (e.g. dimethyl, diethyl, dibutyl, diamyl, dihexyl, 
diheptyl, dioctyl, dinonyl or didecyl phthalate, or dibutyl 
chlorophthalate), glycollates (for example butylphthalyl-butyl glycolate), 
phenols (for example 2,4-di-n-amylphenol or 2,4-di-tert-amylphenol), 
phosphates (for example diphenyl, triphenyl, tricresyl, cresyl diphenyl, 
dioctyl, dioctyl butyl, trioctyl, tridecyl, trixylenyl, 
tri-(isopropylphenyl), tributyl, trihexyl, trinonyl, trioleyl or 
tri-(butoxyethyl) phosphates), citrates (for example triethyl, tributyl, 
trihexyl, trioctyl, trinonyl or tridecyl O-acetyl-citrates), benzoates 
(for example butyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, 
tetradecyl, octadecyl or oleyl benzoates), esters of substituted benzoic 
acids (for example butyl 2-methoxybenzoate, pentyl o-methylbenzoate, decyl 
p-methylbenzoate, lauryl o-chlorobenzoate, propyl 2,4-dichlorobenzoate, 
oleyl 2,4-dichlorobenzoate or octyl p-methoxybenzoate), fatty acid esters 
and dicarboxylic acid esters (for example hexadecyl myristate, dibutyl 
sebacate, dibutoxyethyl succinate, dioctyl adipate, dioctyl azelate and 
benzyl caprylate), esters of polyols (for example decamethylene glycol 
diacetate, triacetylglycerol or tributyroylglycerol, pentaerythritol 
tetracapronate or isosorbitol dicaprylate), fatty acid amides (for example 
N,N-dimethyl-, N,N-diethyl- or N,N-dibutyl-laurylamide), chlorinated 
paraffins, aliphatic or aliphatic-aromatic ethers (for example glycerol 
trialkyl ethers, glycerol 1,3-dialkyl ethers, n-pentadecyl phenyl ether or 
3-pentadecylphenyl ethyl ether), alkyl arylcarbamates (for example ethyl 
N,N-diphenylcarbamate) or mixtures of such liquids. 
The volatile solvents used can be liquids which boil no higher than 
150.degree. C. Examples of these are lower alkyl acetates or propionates 
(for example methyl, ethyl, n-propyl, isopropyl or butyl acetate, or 
methyl or ethyl propionate), ethyl formate, diethyl carbonate, lower 
chloroalkanes (for example carbon tetrachloride, di- and 
tri-chloroethylene, 1,2-dichloropropane, chloroform or amyl chloride), 
ketones (for example acetone, methyl ethyl ketone, diethyl ketone or 
methyl isobutyl ketone), ethers (for example diisopropyl ether, dibutyl 
ether, tetrahydrofuran or dioxane), alcohols (for example methanol, 
ethanol, isoopropanol or butanol), monoethers of diols (for example 
ethylene glycol monomethyl ether or monoethyl ether), hydrocarbons (for 
example cyclohexane, methylcyclohexane, petroleum ether, benzene, toluene 
or xylene), nitromethane, acetonitrile, dimethyl sulfoxide, 
N-methylpyrrolidone, dimethylformamide, tetrahydrothiophene dioxide, 
butyrolactone or 1,2-dimethoxyethane. 
These auxiliary solvents serve to achieve improved dispersion of the UV 
absorber or its solution in a high-boiling solvent. If, however, the UV 
absorber is a liquid of low viscosity, which is readily dispersible due to 
its polar or hydrophilic character, no solvent is necessary, and this 
applies in the case of many of the UV absorbers used according to the 
invention. As a result, the preparation of the emulsions can be 
simplified, and recovery of the auxiliary solvent is no longer necessary. 
If an auxiliary solvent is used, this must be removed again before the 
coating step. This can be effected by heating and/or vacuum treatment, for 
example in a vacuum-spray evaporator or in a rotary vacuum evaporator. 
If the binder of the coating composition is an aqueous solution, a 
dispersion or a latex, the oily phase of the UV absorber or its solution 
in the aqueous phase must be dispersed homogeneously, and this dispersion 
should have the longest possible pot life, during which the dispersed oil 
droplets do not increase in size or the dispersion does not segregate. 
This can be achieved--apart from the use of solvents--by the use of 
surfactants, by the addition of colloids to the aqueous phase or by means 
of appropriately intensive mixing and dispersing machines. 
Examples of suitable dispersing machines are ultrasonic appliances, turbine 
stirrers, homogenizers, colloid mills, bead mills, sand mills or 
high-speed stirrers. 
Examples of colloids, which are added to the aqueous phase and which 
stabilize the resulting dispersions, are polyvinyl alcohol, cellulose 
ethers, polyethylene oxide, salts of polyacrylic acid, gelatine, vegetable 
gum, dextrin, casein or albumin. These colloids are at the same time also 
binders. 
Examples of surface-active dispersing aids can be nonionic, amphoteric, 
anionic or cationic surfactants. Examples of nonionic surfactants are 
esters or ethers of polyethylene oxides or polypropylene oxides or of 
copolymers thereof, fatty acid alkanolamides, ethoxylated alkanolamides, 
partial fatty acid esters of polyols (for example of glycerol, 
polyglycerol, sorbitol, pentaerythritol or sucrose), N-alkylmorpholines or 
long-chain amine oxides. 
Examples of amphoteric surfactants are fatty acid amidoalkyl-betaines, 
fatty acid amidoalkyl-sultaines, fatty acid imidazoline-betaines, 
N-alkyl-.beta.-aminopropionic acids or alkylene 
bis-(amidoalkylglycinates). 
Examples of anionic surfactants are alkali metal salts or ammonium salts of 
fatty acids, of alkyl sulfates, of amido-ethylene oxidesulfates, of 
alkylsulfonic or alkylarylsulfonic acids, of N-alkyl-taurines and 
N-acyl-taurines, of fatty acid isethionates, of alkyl-sulfosuccinates, of 
lignin-sulfonates, of petroleum-sulfonates, of monoalkyl or dialkyl 
phosphates, of N-alkylsarcosines, of alkylsulfonamidoacetic acids, of 
alkyl lactates, of monoalkyl succinates, of fatty acid/protein 
condensation products, of (alkyl)naphthenic acids, of abietic acids, of 
sulfonated fatty acids or of N-acyl-aminocarboxylic acids. 
Examples of cationic surfactants are the quaternary ammonium salts of 
long-chain fatty amines and benzylamines, imidazolinium, pyridinium, 
picolinium, or morpholinium salts having long-chain alkyl radicals, 
quaternary ammonium salts of long-chain alkylamidoalkylamines or 
bis-ammonium salts of quaternary diamines. 
The surfactant can be dissolved beforehand in the oil phase or in the water 
phase, or in both phases. It is also possible to add different surfactants 
to the two phases, but these must not have contradictory activity 
(cationic/anionic). 
In the case of using cationic surfactants, destruction of the oil-in-water 
dispersion can arise on addition of the filler, if the surface of the 
filler carries an electronegative charge, as is the case, for example, 
with silica. This problem can be solved by pretreating the surface of the 
filler. For this purpose, silanes carrying functional groups are used in 
most cases; these appropriately modify the electric charge on the surface, 
an example being 3-(trimethoxysilyl)-propyldimethyl-octadecyl-ammonium 
chloride. 
Where a polyvinyl alcohol is used as the binder and colloid for the coating 
composition, particularly the following surfactants have proved especially 
suitable as dispersing aids for the oily phase containing the UV absorber: 
diisobutylphenoxyethyl-dimethyl-benzyl-ammonium chloride, 
didecyl-dimethyl-ammonium chloride, tallow fat-ammonium acetate, 
oleyl-dimethylbenzyl-ammonium chloride and alkylarylsulfonates. 
The effect of the alkylarylsulfonates can be further enhanced by an 
addition of wetting agents, which likewise are surfactants. Examples of 
these are sodium dioctylsulfosuccinate and alkylnaphthalenesulfonates. 
If the binder is applied as a solution in an organic solvent to the coating 
composition, the UV absorber and the other additives do not need to be 
dispersed. They are then added directly to the binder solution, or they 
are dissolved beforehand in an organic solvent. 
The coating composition is applied to the carrier, which in most cases is a 
paper, and dried by heating. The recording material prepared in this way 
contains preferably 1 to 5,000 mg/m.sup.2, especially 200-1,200 
mg/m.sup.2, of the UV absorber. 
The recording material thus prepared, which contains at least one of the UV 
absorbers according to the invention in its surface layer and can contain 
the other additives mentioned, is also a subject of the invention. This 
recording material has not only a good absorption capacity for ink jet 
dyes, but also imparts high light fastness to the imprinted dye. The 
nature of the ink and of the dye dissolved therein and the type of 
printing device (printer) used are immaterial here. 
In the case of the printers used nowadays, a distinction is made between 
those having a continuous ink jet and an intermittent ink jet. There are 
also drop-on-demand printers, bubble-jet printers, compound-jet printers 
or ion beam printers. The recording material according to the invention 
can be used for all these types of process equipment. 
The inks are in most cases aqueous inks, but they can also be solutions of 
the dye in an organic solvent or in a molten wax. In most cases, aqueous 
inks also contain water-soluble solvents, for example monoethylene, 
diethylene, triethylene or higher ethylene glycols, propylene glycol, 
1,4-butanediol or ethers of such glycols, thiodiglycol, glycerol and its 
ethers and esters, polyglycerol, mono-, di- and tri-ethanolamine, 
propanolamine, dimethylformamide, dimethyl sulfoxide, dimethylacetamine, 
N-methylpyrrolidone, 1,3-dimethylimidazolidone, methanol, ethanol, 
isopropanol, n-propanol, diacetone-alcohol, acetone, methyl ethyl ketone 
or propylene carbonate. 
Aqueous inks contain water-soluble dyes, such as are also known for the 
dyeing of natural fibres. This can be, for example, monoazo dyes, disazo 
dyes or polyazo dyes, or phthalocyanine dyes. Examples of these are Food 
Black 2, C.I. Direct Black 19, C.I. Sulfur Black 1, Acid Red 35, Acid 
Yellow 23 or copper phthalocyanines. 
Aqueous inks can also contain minor quantities of various additives, for 
example binders, surfactants, biocides, corrosion inhibitors, chealating 
agents, pH buffers or conductivity additives. They can also contain 
water-soluble UV absorbers or other water-soluble light stabilizers. In 
general, however, the addition, according to the invention, of a UV 
absorber to the recording material suffices. 
If the ink is a non-aqueous ink, it represents a solution of the dye in an 
organic solvent or solvent mixture or in a molten wax. Examples of 
solvents used for this purpose are alkylcarbitoles, alkylcellosolves, 
dialkylformamides, dialkylacetamides, alcohols, especially alcohols having 
1-4 C atoms, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl 
ketone, diisopropyl ketone, dibutyl ketone, dioxane, ethyl butyrate, ethyl 
isovalerate, diethyl malonate, diethyl succinate, methyl perlargonate, 
butyl acetate, triethyl phosphate, ethylglycol acetate, toluene, xylene, 
tetralin and petroleum spirit fractions. Examples of solid waxes as 
solvents are stearic acid or palmitic acid. 
Such solvent-based inks contain dyes soluble therein, for example Solvent 
Red, Solvent Yellow, Solvent Orange, Solvent Blue, Solvent Green, Solvent 
Violet, Solvent Brown or Solvent Black. Such inks can also contain yet 
further additives, such as are listed above for aqueous inks. 
The examples which follow illustrate the preparation of a coating 
composition used according to the invention and of the recording material 
obtained therefrom. They also illustrate the stabilizing effect of the 
addition of the UV absorber. Percentage data relate to the weight, unless 
otherwise stated.

EXAMPLE 
Coating compositions are prepared which are based on silica/polyvinyl 
alcohol and contain a dispersion of a UV absorber, with and without an 
addition of tricresyl phosphate as an oil phase. In the case of the 
additional use of tricresyl phosphate (TCP), this is added in a UV 
absorber:TCP weight ratio of 2:1. The dispersant used is the following 
solution of two anionic surfactants: 
10 g of phenylsulfonate HSR paste (65%), Hoechst AG, 
1.3 g of Nekal.RTM. BX paste (62.5%), BASF AG, and 
13.7 g of water. 
1.6 g of surfactant solution are used per g of UV absorber and TCP. 
The UV absorber and, if appropriate, the TCP are dissolved in a little 
ethyl acetate. A solution of 3.27 g of polyvinyl alcohol (PVA) in 68 g of 
water is mixed with the surfactant solution, and this mixture is mixed 
with the ethyl acetate solution of the UV absorber, using a magnetic 
stirrer. The mixing ratios can be seen from Table 1. 
The ethyl acetate is removed at 45.degree. C. in a rotary evaporator, a 
homogeneous dispersion of the oily phase in the PVA solution being formed. 
4.0 g of silica (type 244, Grace & Co) are added in each case to 3.27 g of 
PVA, and the dispersion is ultrasonically homogenized for 30 seconds. The 
resulting coating composition is filtered through a polyester fibre screen 
of 24 .mu.m mesh width, and the pH is adjusted to 7.0 by the addition of 
2N sodium hydroxide solution. The coating composition (without UV 
absorber) contains 9.7% of solids. 
TABLE 1 
__________________________________________________________________________ 
Quantities used per 3.27 g of PVA and 4.0 g 
of silica 
Surfactant 
Ethyl 
Sample No. 
UV absorber 
UV absorber 
TCP solution acetate 
__________________________________________________________________________ 
1 none -- -- 0.10 g 
2 A-1 0.81 g -- 1.30 g -- 
3 A-1 0.81 g -- 1.30 g 5 g 
4 A-2 0.75 g -- 1.20 g 5 g 
5 A-3 0.60 g -- 0.96 g 5 g 
6 A-3 0.60 g 0.30 g 
1.44 g 5 g 
7 A-4 0.80 g -- 1.29 g 5 g 
__________________________________________________________________________ 
The following UV absorbers are used: 
##STR14## 
and about 43% of 
##STR15## 
##STR16## 
##STR17## 
##STR18## 
The coating compositions are applied in a thickness of 50 .mu.m by means o 
a wire-wound draw bar to photographic paper. The coating obtained after 
warm-air drying is about 5 g/m.sup.2 and contains 1 mmol of UV absorber 
per m.sup.2. 
The recording material thus prepared is printed with a yellow ink and a red 
ink in an ink-jet printing device. The yellow ink is prepared from 
5 parts of Acid Yellow 23, 
50 parts of diethylene glycol and 
45 parts of water. 
The red ink is prepared analogously, using Acid Red 35. The inks are 
filtered through an ultrafilter of 0.3 .mu.m pore width and filled into 
the ink cartridges of the "Think Jet" (Hewlett-Packard). Proofs are 
prepared at a dot density of 75 dots per cm. 
The colour density (intensity) of the stained areas is determined by means 
of a densitometer (Macbeth TR 924), using a status A filter. The proofs 
are then irradiated in an Atlas weatherometer with a xenon lamp of 81 klux 
illumination behind a window glass filter. The colour density is then 
measured again. The percentage colour density loss during the irradiation 
is given in Table 2. 
TABLE 2 
______________________________________ 
Colour density loss in % after 
irradiation of 
Yellow ink Red ink 
Sample No. 
UV Absorber 15 kJ/cm.sup.2 * 
5 kJ/cm.sup.2 * 
______________________________________ 
1 none 53 71 
2 A-1 43 53 
3 A-1 46 53 
4 A-2 38 38 
5 A-3 43 48 
6 A-3/TCP 40 37 
7 A-4 35 35 
______________________________________ 
*Measured amount of radiation energy in the 300-800 nm range.