CA1328659C - Use of certain benzotriazole derivatives as light stabilizers for recording materials for ink-jet printing - Google Patents

Abstract

Use of certain benzotriazole derivatives as light stabilizers for recording materials for ink-jet printing Abstract UV-absorbers of the formula I
(I) in which n is 1 to 4, R is H, C1-C12alkyl, C5-C8cycloalkyl, phenyl or C7-C9phenylalkyl, R1 is H, Cl, C1-C4alkyl or C1-C4alkoxy and R2 is an n-valent hydrophilic group, are especially suitable for the light sta-bilization 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.

Description

1 3 2 8 6 ~

3-16342/+ ~-~: ~ " -, "
'-'. :' : ,..:' `'''"'-'. :''' ~-Use of certaln benzotriazole derivatives as light stabillzers for recording material6 for ink-~et printing `'. ':. .'"

The invention relates to the use of certain ~V absorbers of the type of 2-(2-hydroxyphenyl)-benzotriazoles as light stabilizers for re~
cording 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 ~et i8 a very rapid printing process, -which can be controlled by electrical signals. In this case, a fine ~et of ink droplets is sprayed through a nozzle onto the recordlng 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, whlch are coated with a dye-bindlng layer. Because of the fineness of the nozzles, pigments are hardly used, but predominantly dyes which are fully dis~olved in the ink ~et medium. However, these dyes generally have a lower llght fastness than the colour pigments usual in conventional printing inks. Conse-quently, recordings made by ink-jet printing have only a limited storage life in the presence of light. In tbe case of prolonged storage in light, they start to fade or to discolour.

In order to solve this problem, lt has already been proposed (US-A-4,256,493) to add a water-soluble UV absorber to the ink. By interaction with the dye, solid partlcle~ can then precipitate in the ink, ~hich block the fine nozzle. A different approach has therefore been taken, by sddiDg light stabili3ers to the recording material.
Thus, in GB-A-2,088,777, an addition of UV absorbers of the ben~o-~' .

13286~

triazole type in combination with sterically hindered phenols ls pro-posed 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 stabili~ation 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 n~w been found that certa~n UV absorbers of the benzotriazole ~ ~:
type are particularly suitable f or this purpose. These are compounds of the formula I . .

[ ¢ ;>~ ~cNzcNyclnR
in which n is l to 4, R is hydrogen, Cl-Cl2alkyl, C5-C8cycloalkyl, phenyl or C7-Cgphenylalkyl~ Rl is hydrogen, chlorine, Cl-c4alkyl or cl-c4alkoxy and, in the case of n - 1, is also -CooR3, R2 a) in the car,e of n - 1, i8 an -oR3 or NR4R5 group, b) in the case of n ~ 2, is a divalent -o-R6-0-, -o-R6-N(R7)-, -N(R7)-R8-N(R7)- group or O_ c) in the case of n - 3, is a trivalent -O-Rll-O- or -N(R7)-R8-~-R8-N~R7)- group and 0~
d) in the c~se of n = 4, is a tetravalent -O-R12-0- or -N(R7)-R8-~-R8 _1_R8_N(R7) group, O~ :
in which R3 i8 hydrogen, cl-cl8alkyl, which is monosubstituted or ~ .
polysubstituted by -OH or -O-CORlO, C3-c3oalkyl which is interrupted by one or more -O- or -N(R7)- and can be monosubstituted or poly-~ :
substituted by -OH or -O-COR10 groups, unsubstituted or OH-substituted ~ 3 ~ 21489-7371 Cs-C12cycloalkyl~ unsubstltuted or 0ll-substituted C2-Clgalkenyl~ C7-Cls-phenylalkyl or C7-CI5alkylph~nylalkyl, glycidyl, furfuryl or u glyco~yl group, R4 and R5 lndependently of on~ another arc hydrogcn, ::
Cl-ClBalkyl, Cl-C4hydroxyalkyl, c3-c30alkyl which ls lnterru~tcd by - -0- or -N(R7)-, C5-C12cycloalkyl, phenyl whlch ls unsubstltuted or :~
substituted by hydroxyl, Cl-C4-alkyl, Cl-C4alkoxy or halogen, C3-C8 alkenyl, C7-C15phenylalkyl or C7-Clsalkylphenylalkyl, or R4 ~nd R5, together wlth the N ato~, fonm a pyrrolldlne, plperldlne, pLperazlne or morphollne rlng, R6 18 C2-C8alkylene~ C4-Cgalkenylene, C4 alkyny-lene, cyclohexylene, c4-c30alkylene whlch 18 lnterrupted by one or more -0-or -N(R7)-, or a group -cH2-cH(oH)-cH2-o-R9-o-cH2-cH(oH)-cH
or .
HzOH
-CH2- : CHz- :
. HzON

R7 ~ hydrogen or Cl-clgalkyl~ R8 18 C2-C12alkylene which can be ln-terrupted by one or more -0-, R9 18 C2-Cgalkylene, C4-Cloalkylene whlch 18 lnterrupted by ~ne or ~ore -0-, cyclohexylene, phenylene or a group R10 1~ Cl-Clgalkyl or phenyl, Rll 18 C3-cloalkanetr~yl and R12 18 C4-C12alkanetetrayl. .
Some of the oompounds of the formula I have been described in EP-A-57,160 published in August 1982 as stabilizers for organic materials, for example polymers, surface coatings or photographic materials. m e preparation of ~;
these compounds is also described therein. Inasmuch as the ccmpounds 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.

e use in inks is also mentioned there. A use in recording materials for ink-jet printing is not mentloned therein.

13286~9 Cl-C12Alkyl R can, for example, be methyl, ethyl, l~opropyl, n-butyl, tert-b~tyl, sec-butyl, tert-pentyl, sec-pentyl, n-hexyl, sec-hexyl, `
n-octyl, ditert-octyl, sec-decyl or n-dodecyl. Cycloalkyl R can e~pe-cially be cyclohexyl. Phenylalkyl R can especially be u,~-dimethyl-benzyl. Prefe~ably, R is a branched alkyl radical, especially tert-butyl.

Cl-C4Alkyl or Cl-C4alkoxy Rl can, for example, be methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, methoxy, ethoxy, isopropoxy, butoxy or tert-butoxy.
~'.' Cl-ClgAlkyl R4, R5, R7 and R10 can be unbranched or branched alkyl, for example methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, lso-butyl, tert-butyl, n-pentyl, lsopentyl, n-hexyl, 2-ethylbutyl, n-octyl, isooctyl, 2-ethylhexyl, 1,1,3,3-tetraethylbutyl, n-decyl, i~odecyl, n-dodecyl, l,1,7,7-tetramethyloctyl, n-tetradecyl or n-octadecyl.

Alkyl R3 which i~ substituted by -OH or -OCOR10 can, for example, be 2-hydroxyethyl, 2-hydroxypropyl, 2-hyd~oxylbutyl, 3-hydroxybutyl, 2,3-dihydroxypropyl, 2,2-di-(hydroxymethyl)-propyl, 4-hydroxybutyl, 6-hydroxyhexyl, 8-hydroxyoctyl, 2-acetoxyethyl, 2-proplonyloxyethyl, 2-octanoyloxypropyl, 2,3-diacetyloxypropyl or 4-acetoxgbuty}.

C3-C30Alkgl R3, R4 and R5 which is interrupted by -O- or -N(R7)- can, for example, be 2-methoxgethgl, 2-ethoxye~thyl, 2-butoxyethyl, 2-iso- -propoxyethyl, 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, R3 i~ a radlcal-~CH2CH20~ CH3 with m = 2-10.
.
cl-c4Hydroxyalkyl R4 and R5 can, for example, be hydroxy~ethyl, 2-hy-droxyethyl, 2-hydroxypropyl, 3-hydroxypropyl or 2-hydroxybutyl. -C5-C12Cycloalkyl R4 and RS can, for example, be cyclopentyl, cyclo-hexyl, methylcyclohexyl, cyclooctyl or cyclododecyl-. ~ ~-:- -::,. ~ -,; - ,: . - .:; ~ :. . . . - . .. - . ~ .. . . .

13286~9 -~. . -. -:
- 5 - ; ~

R3 can also be OH-substituted cycloalkyl, for example 4-hydroxycyclo-hexyl.

C2-C18Alkenyl R3 which can be substituted by OH can, for example, be vinyl, allyl, methallyl, 2-buten-1-yl, oleyl or 4-hydroxy-2-buten-l-yl. C3-C8Alkenyl R4 and R5 can especially be allyl. -,::
C7-ClsPhenylalkyl or c7-cl5alkylphenylalkyl R3, R4 and R5 can, for example, be benzyl, 2-phenylethyl, l-phenylethyl, 3-phenylpropyl, 2-phenylprop-2-yl, 4-methylbenzyl or 4-octylbenzyl.
~",": , ':
Phenyl R4 and R5 which is substituted by alkyl, alkoxy or halogen can, for example, be 4-tolyl, 4-isopropylphenyl, 3-methoxyphenyl, 4-ethoxy- :
phenyl, 4-fluorophenyl or 4-chlorophenyl. ~
: -C2-cgAlkylene R6 and R9 can be branched or straight-chain alkylene, for example 1,2-ethylene, tri-, tetra-, penta-, hexa- or ootamethylene, ~ --2,2-dimethyl-1,3-propylene, 1,2-propylene or 1,2-butylene. In addi-tion, C2-C12alkylene R8 can aLso, for example, be decamethylene or dodecamethylene. ~
: ' ' ' ', Alkenylene or alkynylene R6 càn, for example, be 1,4-but-2-enylene, 1,4-but-2-inylene or 2-methyl-1,4-but-2-enylene.
~, :.. :
Alkylene R6 and R9 which i8 interrupted by -O- or -N(R7)- can, for : -example, be 3-oxa-1,5-pentylene, 3,6-dioxa-1,8-octylene, 3,6,9-trioxa-l,ll-undecylene, 3-methylaza-l,S-pentylene or 3,9-dioxa-5-methylaza-1, ll-undecylene. R6 is especially a radical~~t-CH2CH20-~m~H2CH2- with -~
m ~ 1-6.

An alkanetriyl radical Rll can, for example, be propane-1,2,3-triyl or a CH3C(CHr)3 or C2HsC(CH2~)3 radic~

An alkanetetrayl radical R12 can, for example, be butane-1,2,3,4-tetrayl or a C(CHr )4 radical.

Those rompoundis of the formula I are preferably used in which n is 1 13286~9 or 2, R is Cl-C4alkyl, Rl is hydrogen, chlorine or methoxy, R2 is a) an -oR3 or -NR4R5 group in the case of n = 1 or b) an -o-R6-O- group in the case of n = 2, R3 being hydrogen, Cl-C18alkyl wnich is substi-tuted by l to 3 OH groups, C3-C18alkyl which is interrupted by one or more -O- and can be substituted by one or more -OH, cyclohexyl or allyl, R4 and R5 independently of one another are Cl-Clzalkyl, C2-C4hydroxyalkyl or C3-Cl2alkoxyalkyl or R4 and R5, together with the N
atom, form a pyrrolidine, piperidine, piperazine or morphollne ring, R6 i8 C2-C6alkylene, C4-C14-alkylene which is interrupted by one or more -O- or a -CH2-CH(oH)-CH2-o-R9-o-CH2-CH(oH)-cH2- group and R9 is C2-C4alkylene or C4-C8alkylene which is interrupted by one or more -O-. -Amongst these, those compounds of the formula I are preferred in which R i8 tert-butyl.

Depending on the definition of R2, 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 whlch n is 1 or 2 and R2 i~ an -oR3 or -o-R6-O- group.

With particular preference, tho~e compound~ of the formula I are u~ed in which n is 1 or 2, Rl i~ hydrogen, chlorine or methoxy, R2 is a) a group of the formula -o-t-cH2cH2o-~-H~ -O-t-CH2-ClH-O-~vH or -0-~-CH2~H-CH2-0-~-H, in which u is 1-9, v is 1-6 and w is 1-6, in - -OH
the case of n - 1 and b) a group of the formula -O-~-CH2CH20-~-X or -O-~-CH2-~CH-O ~ in wh~ch 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 i8 1, :
R; is -CooR3 and R2 is -oR3.
~ , .'' Preferably~ those compounds of the formula I are used which are liquid at room temperature.

13286~9 `
- 7 - :
'. , ': - , Examples of individual compounds of the formula I are the conpounds of ~ :
the following formulae:
f-~ ~N HO~ ~C(CH3)3 a) CR - R
CHzCHz - ~ :

1) R ~ -OCH2CHzOCH2CH20C2Hs -: :
2) R ~ -OCH2CH20CH2CH20C4Hg-n i . -3) R - -OCHzCH20H .~
. . :

4) R - -O-~CH2CHzO ~ H : ; ...... ... ;
:- , . .

5) R ~ -o-~CH2CH20 ~ H

6) R ~ -O-~CHzCNz ~ CH3 ":'-''', 7) R -O-~CH2CHzO ~ H `- .
.`,: :,' :.: ' .

8) R ~ -O-~CH2CH20 ~ H m ~ 5~7 9) R ~ -O-~CHzCHzO ~ CH3 m - 5-7 10) R ~ 0 ._, : ~ .
~' ; ":':" ' ,11) R - -NHCH2CH20CH2CH20CHzCHzOC4Hg-n '.
:: I . ':
: ' 12) ~ - -NHC(CHzOH)3 13) R ~ -OCH2CH(OH)CHzOH
; 1, . :
~ 14) R ~ -OCH2CH(OH)CH20C~Hg-n , 1~5) R - -OCH2CH(OH)CH3 .
: '~ .-132~6S9 16) R ~ -NHCH2CH20C2Hs 17) R - -~CH2cH(oH)cH2ocH2c~H-c4N9-n ~: :
2Hs 18) R - -O-CH2CH(OH)CH20C6Hl3-n :~:

19) R - -O-~CH2-CH(CH3)-O ~ H

20) R - -O-~CH2-CH(CH3)-O ~ H m - 3-6 ~:

21~ R - -O-~CH2-CH(CH3)-O ~ CH3 m ~ 3-6 ~

22) R Y -O-~CH2-CH(OH)-CHz ~ H ~ :

23) R ~ -O-~CKz-CH(OH)-CNz ~ H m - 3-5 HO~ ~C(CH3)3 (CH3)3C~ ~OH
b) i ~ N
CH2CH2CO-R-COCHzCH~ ~

24) R ~ -OCH2CHzO- : ::. :
~ .
25) R ~ -O-~CHiCHzO ~ ;~ ~:
:: 26? R - -O-~CH2CHzO ~

27) R - -O-~CH2CHz ~

28) R ~ -O-~CH2CHz ~ m ~ 5-7 -: ~ 29~ R ~ -O-~CH2CH(CH3)-O-~-: 30) R ~ -O-fCH2CH(CH3)-O-~-' ~''' 13286~9 _ 9 _ 31) R ~ -O-CH2CH(OH)CH2-O-(CH2)8-O-CH2CH(OH)CH2-O-. :.

c) C~
CH2CH2CO-R ;

32) R - -OCH2CH20H ~ :
:'..' ~
33) R ~ -O-~CH2CN20 ~ H ~ -.',''.: '.
34) R ~ -o-~CH2CH20 ~ H ~ ~ 5~7 35) R ~ -NH-C(CH20H) 3 ,' , .:
36) R - -N~ ~O .:
._. , ~. :
'.': ' 37) R - -NH-(CHz)3- OCH2CH20CH2CH2-OC4Hg-n .

38) R - -NH-(CHz)3-OC8Hl7 . :.
: 39) R -OCH2CH(OH)cHz-Oc8Hl7 . :~
40) R ~ -OCHzCH20CHzCH2-OC4H9-n :
: 41) R ~ -OCHzCH20CH2CH2-OC~H5 42) R - -OCHlCH(OH)CH2-OcH2cH-cH2 : 43) R - -OCHzCH~OH)CHz-OC4H9-n ' '~ '-.. . ,, , , , ., , ~ ~, , . , ., . , .: , . , .. , , . , . .. . , . . . . :

~o 13286~9 HO~
44) R - -O--~ ~-O~ ~C(CH3)3 (CH3)3C~ ~OH

CH2CH2CO-R--COCHzCH2 45) R - -OCH2CHzOCH2CH20-46) R ~ -O-~CH~CH20 47) R ~ -o-~CH2CH20 ~ n ~ 5-7 48) R ~ -OCH2CH(OH)CHz-O-(CH2)4-O-cH2cH(OH)cH20-~C(CNJ)3 (CN3)3C~ ~ON

CH2cNzco-R-cocH2cH2 49) R ~ -o-CHzCN2-O-50) R ~ _o-~CH2CH20 ~

51) R - -o-~CHZcH20 ~ m - 5~7 :: .
HO~ ~CH3 CHzCH2COR ::

52) R - -OCH2CH20CN2CH20CH

53~ R ~ -O-~CH2CHzO ~ H

"::

: ~: ' 13286~9 ~

54) R - -O-~CH2CH20 ~ CzHs ,.

55) R ~ -OCH2CH(OH)CH20H
.. . .. .
56) R ~ -o-tCH2CH2 ~ H m ~ 8-10 CH~ ~OH

CH2CH2CO--R--COCH2CH2 .

57) R ~ -o-~CH2CH20 58) R ~ -o-~CH2cH

59~ R ~ -O-~CHzCH20 ~ m ~ 8-10 h) H OOC } 3~
~CHICH~COOR' 60) R ~ t-rt.G~Ns R' - -O~CHzCH20~ CN3 61) R ~ tert.C4N~ R' - -0 tCN2CH2 ~ C2Ns 62) R ~ CN3 R' ~ -O~CH2CH20~ CH3 Mixtures of a plurality of compounds of the formula I are frequently ~-obtained in the preparation of the e compounds. For example, the ~ -monoester can be formed ln addition to the dlester in the esterifica-tlon of a diol. Polyalkylene glycol~ are frequently ~echnical ~ix-tures of vary~ng degrees of oxyalkylation. ~hen these are used as the diols, corre~ponding mixtures of compounds of the formula I are ob- --tained. Such mixtures are equally suitable for the use according to ~ ~ -the inventlon as homogeneous compounds. Since such mixtures are ln ~ ~

- 12 - 13286~9 most cases liquid, they can even be of particular advantage.

Examples of these are the compounds 8), ~0), 21), 23), 28), 34), 47) and 51) listed above, or mixtures of 3) and 24), of l9) 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, R300C-~ if ~
~ ~CHzCH2COOR3 in which R and R3 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 llght stabilizer~ for ink-Jet printlng 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 ab~orptlon of the molecule, but be independent of other proper-tie~ 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 agglome-rate on drying out, 80 that the UV absorber is in a very homogeneous distribution on the recording material, whereas corresponding emul-sions or dispersions containing the UV absorbers indicated in Research Disclosure No. 24,239 tend to an agglomeration of the UV sbsorber on drying out. -~ . . :,. ':
The recording material is a two-d~mensional sheet-like structure which .~ '' 13286~9 : .
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, one one side or on both sides, with a ~
material which is particularly receptive for the ink dyes. The re- -cording material can be transparent, for example in the case of pro-jection 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 lncorporated 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 tyes 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 compositlons u~ually consist of a solid filler and a binder as well as minor proportions of additives.

The iller is quantitatively the main constituent of the coating com-position. ~xamples of conventional flllers 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-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, par-tially hydrolysed polyvinyl acetate, cellulose ethers, polyvinyl-pyrrolidone and copolymers thereof, polyethylene oxide, salts of poly-acrylic acid, sodium alginate, oxidized starch, gelatine, casein, vegetable gum, dextrin, albumin, dispersions of polyacrylates or acrylate/methacrylate copolymer6, latices of naturai or synthetic -': .

,. . , . . .... . , ...... . .. - . ... , . , .. . ,. -;. . - - ; . - .. ~ - .. .. .

- .. . . . :, .. . : . :;: ... .. : ... .. : . .

13286~9 ::

rubber, poly(meth)acrylamide, polyvlnyl ethers, polyvinyl esters, copolymers of maleic acid, melamine re~ins, urea resins, or chemically modifled polyvlnyl alcohols, aB descrlbed ln JP-A-86/134,290 or 86/134,291.
':
A dye receptor or mordant, which flxes the dye more finnly to the coatin~, can be added to the blnder. Dye receptors for acid dyes are of catlonlc or amphoterlc nature. Examples of catlonic receptors are poly~erlc ammonlum compounds, for example polyvlnylbenzyl-trlmethyl-ammonlum chlorlde, polydiallyl-dlmethylammonlum chloride, polymeth-acryloxyethyl-dlmethyl-hydroxyethylammonlum chlorlde, polyvlnylbenzyl-methyllmldazollun chloride, polyvinylbenzyl-plcollnium chloride or polyvlnylbenzyl-trlbutylam~onlum chlorlde. Further example6 sre ba~lc poly~ers, ~uch as poly-(dimethyl~lnoethyl methacrylate), polyalkyl-enepolyamlnes and condensatlon products thereof wlth dlcyandiamlde, amlne/eplchlorohydrin polycondensates or the compounds described in JP-A-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, ~
8S/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.~80, 86/58,788, 86/61,887, ~-86/63,477, 86/72,581, 86/95,977 and 86/134,291 or in US-A-4,547,405 and 4,554,181 and also in DE-A-3,417,582 published in M æ ch 1985.
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 W absorbers which æ e not W absorbers according to the invention), viscosity im-provers, fluorescent brighteners, biocides or/and antistatics.
Examples of suitable antioxidants æ e, in particular, sterically hin-dered phenols and hydroquinones, for example the antioxidants listed in GB-A-2,088,777 published in June 1982 or in JP-A-85/72,785, 85/72,786 -and 85/71,796.
Examples of suitable light stabilizers are, in paLticular, organic nickel compounds and sterically hindered amines, for example the light stabilizers mentioned in JP-A-83/152,072, 86/146,591, 86/163,886, 85/72,785 and 86/146,591 or in G2-A-2,088,777, JP-A-084/169,883 and 132~6~9 :

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. Alter-natively, 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 coatlng 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 dissol~e it in an organic solvent and to disperse thi~ solution in the coating composition.
' :, :: - .
The solvent u6ed is preferably of low volatility, so that the UV ab-~orber remalns in the liquid state even after prolonged ~torage of the recording material. For preparing the dispersions, however, a vola-tile auxiliary 601vent is also added in most cases, and this is re- -moved again during the proces6 of protucing the recording material.
~xamples of low-~olatility ~olvents are organic liquids of oily character and high boiling polnt, for example phthalates (e.g. di-methyl, diethyl, dibutyl, tiamyl, 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), pho6phates (for example diphenyl, triphenyl, tricresyl, cresyl diphenyl, dioctyl, dioctyl butyl, trioctyl, tridecyl, trixylenyl, tri-(isopropylphenyl), tri- ~
butyl, trihexyl, trinonyl, trioleyl or tri-(butoxyethyl) phosphates~, -citrates (for example triethyl, tributyl, trihexyl, trioctyl, trinonyl or tridecyl 0-acetyl-citrates), benzoates (for example butyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, octadecyl or oleyl benzoates), e8ters of substituted benzoic acids (for example butyl 2-methoxybenzoate, pentyl o-methylbenzoate, decyl p-methylbenzo-ate, lauryl o-chlorobenzoate, propyl 2,4-dichlorobenzoate, oleyl 2,4-dichlorobenzoate or octyl p-methoxybenzoate), fatty acid esters and :: .

1~2~6~9 :: -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, penta-erythritol tetr~capronate or isosorbitol dicaprylate), fatty acid amides (for example N,N-dimethyl-, N,N-diethyl- or N,N-dibutyl-lauryl-amide), chlorinated parafflns, 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 150C. 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 chloro- -slkanes (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 iso-butyl ketone), ethers (for example diisopropyl ether, dibutyl ether, tetrahydrofuran or dioxane), alcohols (for example methanol, ethanol, isoopropanol or butanol), monoethers of diols tfor example ethylene glycol mono~ethyl ether or monoethyl ether), hydrocarbons (for example cyclohexane, methylcyclohexane, petroleum ether, benzene, toluene or ;~
xylene), nitromethane, acetonitrile, dimethyl sulfoxide, ~-methylpyr-rolidone, dimethylformamide, tetrahydrothiophene dioxide, butyrol~
actone 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 disper-sible due to its polar or hydrophilic character, no solvent is neces-sary, and this applies in the case of many of the UV absorbers used accord~ng to the invention. As a result, the preparation of the emul-sions can be simplified, and recovery of the auxiliary solvent is no longer necessary. --~ . ....

13286~9 If an auxiliary solvent is used, this must be removed again before the coating step. This can be effected by heating snd/or vacuum treat-ment, 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 solu-tion in the aqueous phase must be disper9ed homogeneously, and this dispersion should have the longest pos8ible 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 dis- -persing machines.

Exa~ples 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 ether~, polyethylene oxide, ~alts of polyacrylic acid, gelatine, vege-table gum, dextrln, casein or albumln. These colloids are at the same time also binders.

Examples of surface-active dispersing aids can be nonionic, ampho-teric, anionic or cationic Hurfactants. Examples of nonionic sur-factants are esters or ethers of polyethylene oxides or polypropylene oxides or of copolymers thereof, fatty acid alkanolamides, ethoxy-lated 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-B-aminopropionic acids or alkylene bis-(amidoalkylgly~inates).

132~6~9 Examples of anionic surfactants are alkali metal salts or ammonium salts of fatty acids, of alkyl sulfates, of amido-ethylene oxide- ~ -sulfates, 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 alkylsulfon-amidoacetic 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-aminocarboxy-lic 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-ammonlum salts of quaternary diamlnes.

The surfactant can be dissolved beforehand in the oil phase or in the water pha~e, or in both phase~. 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 cationlc 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 u~sd in most cases; these appropriately modify the electric charge on the surface, an example being 3-ttrimethoxysilyl)-propyl-dimethyl-octadecyl-ammonium chloride.

Where a polyvinyl alcohol is used as the binder and colloid for the coating composition, par~icularly the following surfactants have proved especially ~uitable as dispersing aids for the oily phase containing the UV absorber:
diisobutylphenoxyethyl-dimethyl-benzyl-ammonium chloride, didecyl-di- ;
methyl-ammonium chloride, tallow fat-a~monium acetate, oleyl-dimethyl-- 19 - 1328659 ;-benzyl-a~monium chloride and alkylarylsulfonates.

The effect of the alkylarylsulfonates can be further enhanced by an addition of wetting agents, which likewise are surfactants. ~xamples of these are sodi~m dioctylsulfosuccinate and alkylnaphthalenesulfo- ~ -nates. --: :.
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/m2, especially 200-1,200 mg/m2, of the UV absorber. -The recording material thus prepared, which contains at least one of the UV absorbers sccording to the invention in its surface layer and can contain the other additives mentioned, i8 also a subJect of the invention. This recording material has not only a good absorptlon capacity for ink Jet dyes, but slso imparts hlgh light fastne~ to the imprinted dye. The nature of the ink ant of the tye dissolved therein and the type of printing device (printer) used are immaterial here. -~
. ~ ..
In the case of the printers used nowadays, a distinction ls made be-tween those having a contlnuous ink ~et and an intermittent ink ~et.
There are also drop-on-demand printers, bubble-~et printers, compound-~et 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 solu-tions 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, thiodigly-col, glycerol and lts ethers and esters~ polyglycerol, mono-, di- and .

:

1328659 ~ ~

.
tri-ethanolamine, propanolamine, dimethylformamide, dimethyl s~lfo-xide, dimethylacetamine, N-methylpyrrolidone, 1,3-dimethylimida7-o-lidone, 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, Acit 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-solu~le light stabilizers. In general, however, the addition, according to the ` ~ -lnvention, of a UV absorber to the recording material suffices.

If the ink is 8 non-aqueous ink, it represents a solution of the dye in an organic solvént or solvent mixture or in a molten wax. Ex~mples -of solvent~ used for this purpose are alkylcarbitoles, alkylcello-solves, dialkylformamlte~, tialkylacetamltes, alcohols, especially alcohol~ havlng 1-4 C atoms, acetone, methyl ethyl ketone, tiethyl ketone, methyl lsobutyl ketone, dllsopropyl ketone, dibutyl ketone, dioxane, ethyl butyrate, ethyl isovalerate, diethyl malonate, diethyl -~
succlnate, methyl perlargonate, butyl acetate, triethyl phosphate, ethylgIycol acetate, toluene, xylene, tetralln and petroleum spirit fractions. Examples of solld waxes as solvents are stearlc acld or palmitic acld.

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 illastrate the preparation o~ a coating .

' ':' 13286~9 composition used according to the invention and of the recording mat-erial 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 oily phase. In the case of the addltional use of tricresyl phosphate (TCP), this i8 added in a UV absorber:TCP weight ratio of 2:1. The dispersant used is the following solution of two anionic surfactants:
g of phenylsulfonate HSR paste (65%), Hoechst AG, 1.3 g of Nekal~ 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) ln 68 g of water is mixed with the surfactant solution, and this mixture is mlxed with the ethyl acetate solution of the UV absorber, using a magnetlc stirrer. The mixing ratios can be seen from Table 1.

The ethyl acetate is removed at 45C in a rotary evaporator, a homo-geneous 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 dlspersion is ultrasonically ho2ogenized for 30 seconds. The resulting coating composition is filtered through a polyester fibre screen of 24 ~m mesh width, and the pH is ad~usted to 7.0 by the addition of 2~ sodium hydroxide solution. The coating com-position (without UV absorber) contains 9.7Z of solids.

:: . : .. ~ . ~ . - .. - ~ . . - . ...... .. .... ..... .. ... . .

--` 13286~9 :
Table 1 ~ -.... .. .
0,uantities used per 3.27 g of PVA and 4.0 g :::
of silica .~ :
Sample No. UV absorber UV absorber TCP Surfactant Ethyl solution acetate .- ~ :
1 none - - 0.10 g 2 A-l 0.81 g - 1.30 g 3 A-l 0.81 g - 1.30 g 5 g -~
4 A-2 0.75 g - 1.20 g 5 g .
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:
~ N NO~ ~C(CN3)3 `~
A-l mixture of about 57% of ! !~
CH2CH2COO(CN2CH20 ~ H
and about 43X of C~CK3)J .

CH2CN2C00-~CHzCNzO ~ OC-CHzCH2 n- 6 . .
N0` ~C(CH3)3 CN2CH2C00-~CHzCH2 ~ H n ~ 4 .

. ..:

, ,.

13286~9 ~ ~0~ /C(C~I~3 ' ~

The coating compositionæ are applied in a thickneææ of 50 ~m by means ~ -of a wire-wound draw bar to photographic paper. The coating obtained after warm-air drying is about 5 g/m2 and containæ 1 mmol of UV
absorber per m2, ' The recording material thus prepared is printed with a yellow ink and a red ink ln an ink-~et printing device. The yel}ow ink iæ pre- `
pared from S parts of Acid Yellow 23, 50 parts of diethylene glycol ant 45 part~ of water.
:
The red lnk is prepared analogously, using Acid Red 35. The inkæ are ~ ~
flltered through an ultrafilter of 0.3 pm pore width and filled into -the ink cartridge8 of the Think Jet (Hewlett-Packard). Proofs are prepared at a dot density of 75 dots per cm.

The colour density (intqnæity) of the stained areas is determined by means of a denæitometer (Macbeth TR 924~, using a status A filter.
The proofæ are then irradiated in an AtIas weatherometer with a xenon la~p of 81 klux illumination behind a window glass filter. The colour density is then measured again. The percentage colou~ density 1099 during the irradiation is given in Table 2.
, .
~ ~a6,~ k - ~ -~- :
.~.:,, 13286~
- 24 - ::~-.'~: . . :
Table 2 Colour density loss in % after .
Sample No. UV absorber irradiation of Yellow ink Red ink ..
15 kJ/cm2 *) 5 kJ/cm2 *) ::.
....
1 none 53 71 :. -2 A-l 43 53 3 A-l 46 53 .-4 A-2 38 38 ~
A-3 43 48 . ~ :

7 A-4 35 35 .` : -*) Mea~ured amount of radiation energy in the 300-800 nm range.
'',"' . . ': .

":

. ~ ': ' .
'. ' ' ....
- ~

- ' : ' ' ' : '. ' : ~
:- ~,:

:~-:: ' ' ,: ':
-

Claims (16)

1. The use of a compound of the formula I

I

in which n is 1 to 4, R is hydrogen, C1-C12alkyl, C5-C8cycloalkyl, phenyl or C7-C9phenylalkyl, R1 is hydrogen, chlorine, C1-C4alkyl or C1-C4alkoxy and, in the case of n = 1, is also -COOR3, and R2 a) in the case of n = 1, is an -OR3 or NR4R5 group, b) in the case of n = 2, is a divalent -O-R6-O-, -O-R6-N(R7)-, -N(R7)-R8-N(R7)- group or c) in the case of n = 3, is a trivalent or -N(R7)-R8-?-R8-N(R7)- group and d) in the case of n = 4, is a tetravalent or -N(R7)-R8-?-R8'-?-R8-N(R7)- group, in which R3 is hydrogen, C1-C18alkyl which is monosubstituted or poly-substituted by OH or -O-COR10, C3-C30alkyl which is interrupted by one or more -O- or -N(R7)- and can be monsubstituted or polysubstituted by -OH or -O-COR10 groups, unsubstituted or OH-substituted C5-C12-cycloalkyl, unsubstituted or OH-substituted C2-C18alkenyl, C7-C15-phenylalkyl or C7-C15alkylphenylalkyl, glycidyl, furfuryl or a glyco-syl group, R4 and R5 indenpendently of one another are hydrogen, C1-C18alkyl, C1-C4hydroxyalkyl, C3-C18alkyl which is interrupted by -O-or -N(R7)-, C5-C12cycloalkyl, phenyl which is unsubstituted or substi-tuted by hydroxyl, C1-C4alkyl, C1-C4alkoxy or halogen, C3-C8alkenyl, C7-C15phenylalkyl or C7-C15alkylphenylalkyl or R4 and R5, together with the N atom, form a pyrrolidine, piperidine, piperazine or mor-pholine ring, R6 is C2-C8alkylene, C4-C8alkenylene, C4alkynylene, cyclohexylene, C4-C30alkylene which is interrupted by one or more -O-or -N(R7)- or a group -CH2-CH(OH)-CH2-O-R9-O-CH2-CH(OH)-CH2- or R7 is hydrogen or C1-C18alkyl, R8 is C2-C12alkylene which can be in-terrupted by one or more -O-, R9 is C2-C8alkylene, C4-C10alkylene which is interrupted by one or more -O-, cyclohexylene, phenylene or a group R10 is C1-C18alkyl or phenyl, R11 is C3-C10alkanetriyl and R12 is C4-C12alkanetetrayl, as a light stabilizer for recording materials for ink-jet printing.

2. The use according to claim 1 of a compound of the formula I, in which n is 1 or 2, R is C1-C4alkyl, R1 is hydrogen, chlorine or me-thoxy, R2 is a) an -OR3 or -NR4R5 group in the case of n = 1 or b) an -O-R6-O- group in the case of n = 2, R3 being hydrogen, C1-C18alkyl which is substituted by 1 to 3 OH groups, C3-C18alkyl which is interrupted by one or more -O- and can be substituted by one or more -OH, cyclohexyl or allyl, R4 and R5 independently of one another being C1-C12alkyl, C2-C4hydroxyalkyl or C3-C12alkoxyalkyl, or R4 and R5, together with the N atom, forming a pyrrolidine, piperidine, piperazine or morpholine ring and R6 being C2-C6alkylene, C4-C14alky-lene which is interrupted by one or more -O-, or a -CH2-CH(OH)-CH2-O-R9-O-CH2-CH(OH)-CH2-group, and R9 is C2-C4-alkylene or C4-C8alkylene which is interrupted by -O-.

3. The use according to claim 1 of a compound of the formula I, in which R is tert-butyl.

4. The use accordlng to claim 1 of a compound of the formula I, in whlch n is 1 or 2 and R2 is an -OR3 or -O-R6-O- group.

5. The use according to claim 1 of a compound of the formula I, in which n is 1 or 2, R1 is hydrogen, chlorine or methoxy and R2 is a) a group of the formula , or , in which u is 1-9, v is 1-6 and w is 1-6, in the case of n = 1 or b) is a group of the formula or , in which x is 1-7 and y is 1-4, in the case of n = 2.

6. The use according to claim 1 of a compound of the formula I, in which n is 1, R1 is -COOR3 and R2 is -OR3.

7. The use according to claim 1 of a compound of the formula I, which is liquid at room temperature.

8. A recording material, stabilized against light-induced damage, for ink-jet printing, consisting of a two-dimensional sheet-like structure having a surface printable by ink jet, wherein the printable surface contains at least one compound of the formula I
I

in which n is 1 to 4, R is hydrogen, C1-C12alkyl, C5-C8cycloalkyl, phenyl or C7-C9phenylalkyl, R1 is hydrogen, chlorine, C1-C4alkyl or C1-C4alkoxy and, in the case of n = 1, is also -COOR3, and R2 a) in the case or n = 1, is an -OR3 or NR4R5 group, b) in the case of n = 2, is a divalent -O-R6-O-, -O-R6-N(R7)-, -N(R7)-R8-N(R7)- group or c) in the case of n = 3, is a trivalent or -N(R7)-R8-?-R8-N(R7)- group and d) in the case of n = 4, is a tetravalent or -N(R7)-R8-?-R8'-?-R8-N(R7)- group, in which R3 is hydrogen, C1-C18alkyl which is monosubstituted or poly-substituted by OH or -O-COR10, C3-C30alkyl which is interrupted by one or more -O- or -N(R7)- and can be monosubstituted or polysubstituted by -OH or -O-COR10 groups, unsubstituted or OH-substituted C5-C12-cycloalkyl, unsubstituted or OH-substituted C2-C18alkenyl, C7-C15-phenyalkyl or C7-C15alkylphenylalkyl, glycidyl, furfuryl or a glyco-syl group, R4 and R5 independently of one another are hydrogen, C1-C18alkyl, C1-C4hydroxyalkyl, C3-C18alkyl which is interrupted by -O-or -N(R7)-, C5-C12cycloalkyl, phenyl which is unsubstituted or substi-tuted by hydroxyl, C1-C4alkyl, C1-C4alkoxy or halogen, C3-C8alkenyl, C7-C15phenylalkyl or C7-C15alkylphenylalkyl or R4 and R5, together with the N atom, form a pyrrolidine, piperidine, piperazine or mor-pholine ring, R6 is C2-C8alkylene, C4-C8alkenylene, C4alkynylene, cyclohexylene, C4-C30alkylene which is interrupted by one or more -O-or -N(R7)- or a group -CH2-CH(OH)-CH2-O-R9-O-CH2-CH(OH)-CH2- or R7 is hydrogen or C1-C18alkyl, R8 is C2-C12alkylene which can be in-terrupted by one or more -O-, R9 is C2-C8alkylene, C4-C10alkylene which is interrupted by one or more -O-, cyclohexylene, phenylene or a group R10 is C1-C18alkyl or phenyl, R11 is C3-C10alkanetriyl and R12 is C4-C12alkanetetrayl.

9. A recording material according to claim 8, wherein the sheet-like structure is a coated paper.

10. A recording material according to claim 8, wherein the printable surface contains a cationic dye acceptor in addition to the compound of the formula I.

11. A recording material according to claim 8, wherein the printable surface contains an antioxidant, a further light stabilizer, a fluore-scent brightener or/and a biocide in addition to the compound of the formula I.

12. A process for producing a recording material, stabilized against light-induced damge, for ink-jet printing, which comprises coating a two-dimensional carrier with a coating composition which contains at least one compound of the formula I

I

in which n is 1 to 4, R is hydrogen, C1-C12alkyl, C5-C8cycloalkyl, phenyl or C7-C9phenylalkyl, R1 is hydrogen, chlorine, C1-C4alkyl or C1-C4alkoxy and, in the case of n = 1, is also -COOR3, and R2 a) in the case of n = 1, is an -OR3 or NR4R5 group, b) in the case of n = 2, is a divalent -O-R6-O-, -O-R6-N(R7)-, -N(R7)-R8-N(R7)- group or c) in the case of n = 3, is a trivalent or -N(R7)-R8-?-R8-N(R7)- group and d) in the case of n = 4, is a tetravalent or -N(R7)-R8-?-R8'-?-R8-N(R7)- group, in which R3 is hydrogen, C1-C18alkyl which is monosubstituted or poly-substituted by OH or -O-COR10, C3-C30alkyl which is interrupted by one or more -O- or -N(R7)- and can be monosubstituted or polysubstituted by -OH or -O-COR10 groups, unsubstituted or OH-substituted C5-C12-cycloalkyl, unsubstituted or OH-substituted C2-C18alkenyl, C7-C15-phenylakyl or C7-C15alkylphenylalkyl, glycidyl, furfuryl or a glyco-syl group, R4 and R5 indenpently of one another are hydrogen, C1-C18alkyl, C1-C4hydroxyalkyl, C3-C18alkyl which is interrupted by -O-or -N(R7)-, C5-C12cycloalkyl, phenyl which is unsubsituted or substi-tuted by hydroxyl, C1-C4alkyl, C1-C4alkoxy or halogen, C3-C8alkenyl, C7-C15phenylalkyl or C7-C15alkylphenyalkyl or R4 and R5, together with the N atom, form a pyrrolidine, piperidine, piperazine or mor-pholine ring, R6 is C2-C8alkylene, C4-C8alkenylene, C4alkynylene, cyclohexylene, C4-C30alkylene which is interrupted by one or more -O-or -N(R7)- or a group -CH2CH(OH)-CH2-O-R9-O-CH2-CH(OH)-CH2- or R7 is hydrogen or C1-C18alkyl, R8 is C2-C12alkylene which can be in-terrupted by one or more -O-, R9 is C2-C8alkylene, C4-C10alkylene which is interrupted by one or more -O-, cyclohexylene, phenylene or a group R10 is C1-C18alkyl or phenyl, R11 is C3-C10alkanetriyl and R12 is C4-C12alkanetetrayl.

13. A process according to claim 12, wherein the coating composition contains in an aqueous phase an aqueous binder and in an oil phase a compound of formula I and the compound of the formula I is homogeneously dispersed as the oil phase in the aqueous phase of the coating composition, it being possible for the compound of the formula I to be in a form dissolved in an oily liquid.

14. Process according to claim 12, wherein a surfactant is added to the aqueous phase or to the oily phase.

15. A compound of the formula II

(II) in which R and R3 are as defined in claim 1.

16. A compound according to claim 15 of the formula II, in which R is tert-butyl.