Method for coloring substrates from polypropylene

The present invention relates to a process for coloring a substrate from polypropylene, which comprises

(A) pretreating a substrate from polypropylene with an aqueous pretreatment liquor comprising

(a) at least one resin selected from melamine derivatives, dimethyloldihydroxyethyle- neurea (DMDHEU) and derivatives of DMDHEU, and (b) at least one thickener,

(B) printing on said pretreated substrate by the ink jet process, and thereafter

(C) aftertreating said substrate with an aqueous formulation comprising at least one binder.

The present invention finally relates to substrates obtainable by the process of the present invention.

It is known to treat textile materials which are to be printed by the ink jet process for example with a pretreatment liquor to improve the application properties of the printed textiles. This pretreatment is intended to improve ink holdout on the textile substrate and to achieve a higher color strength and also better fixation of the inks on the substrate. Goals include distinctly crisper contours (improved definition) for the prints on the substrate in order that higher resolutions (higher dpi) may be achieved for the prints. Goals further include high in-service fastnesses, for example washfastness and rubfastness.

EP-A 0 928 841 describes the use of natural thickeners and of bivalent metal salts to print direct dyes and pigments onto silk. The use of bivalent metal salts is not desirable in several cases.

WO 2004/031473 discloses pretreating textiles with a pretreatment liquor comprising at least one polycationic compound and at least one thickener. The textiles obtained exhibit improved ink holdout when printed. Fabric hand of printed textiles thus obtainable, although not adversely affected, could do with improvement in many cases. The rub- fastness of printings with inks based on pigments are, however, in need of improvement.

WO 2006/000384 suggests to pretreat textile substrates with a liquor containing a thickener and a resin selected from melamine derivatives, dimethyloldihydroxyethyle- neurea (DMDHEU) and derivatives of DMDHEU and then print onto said substrates with the ink-jet method. When coloring substrates from polypropylene some properties of printed images such as the rub fastness leave room for improvement. In particular, the rub fastness may be improved.

The present invention therefore had for its object to provide a process which avoids the disadvantages mentioned at the beginning and especially provides substrates from polypropylene which, after printing, show improved properties such as rub fastness after repeated bending or folding. Furthermore, inks shall exhibit good holdout on print- ing. The present invention further had for its object to provide printed substrates from polypropylene which avoid the above-identified disadvantages of the prior art, especially any deterioration in fabric hand and reduced rub fastness after repeated bending or folding.

We have found that this objective is achieved by the process defined at the beginning.

The process of the present invention utilizes substrates from polypropylene which may take any form. Preferably, substrates from polypropylene are flexible which means that they can be repeatedly bent or folded manually without deterioration of mechanical properties, for example films and foils, preferably textile substrates such as fibers, mi- crofibers, yarns, threads, knits, wovens, nonwovens and garments composed of polypropylene or mixtures comprising polypropylene.

Preference is given to utilizing sheetlike textile substrates such as for example non- wovens and knits.

According to the present invention, textile substrates are initially treated in step (A) with an aqueous pretreatment liquor comprising

(a) at least one resin selected from melamine derivatives, dimethyloldihydroxy- ethyleneurea (DMDHEU) and derivatives of DMDHEU, and (b) at least one thickener.

Examples of useful resins (a) are dimethyloldihydroxyethyleneurea (DMDHEU)

and derivatives of DMDHEU, for example etherification products of DMDHEU with for example Ci-C4-alkanol, especially with methanol and with ethanol. Further useful de- rivatives of DMDHEU are bridged derivatives disclosed in EP 0 923 560, and mixedly alkylated or hydroxyalkoxyalkylated bis-4,5-dihydroxyimidazolidin-2-ones as described in WO 98/29393.

Preference is given to choosing resins (a) from melamine derivatives which may be singly to sixtuply condensed with one or more aldehydes and etherified with at least one aliphatic alcohol. At least one aldehyde is selected from C6-Ci4-arylaldehydes, for example 2-naphthaldehyde, 1-naphthaldehyde and especially benzaldehyde,

and aliphatic aldehydes such as

Ci-Cio-alkylaldehydes, wherein Ci-Cio-alkyl is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1 ,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl, n-heptyl, n- octyl, n-nonyl, n-decyl; more preferably Ci-C4-alkyl such as methyl, ethyl, n- propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl;

and most preferably formaldehyde.

Useful aliphatic alcohols include Ci-Cio-alkanols, especially primary Ci-Cio-alkanols and most preferably methanol and ethanol. Useful aliphatic alcohols further include polyhydric alcohols such as for example ethylene glycol, propylene glycol, butylene glycol, pentane-1 ,2-diol, hexane-1 ,2-diol, 1 ,3-propanediol, 1 ,4-butanediol, 1 ,6- hexanediol, 1 ,12-dodecanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, glycerol, diglycerol, triglycerol, polyethylene glycol having on average from 5 to 50 ethylene oxide units per molecule (number average), polypropylene glycol having on average from 4 to 50 propylene oxide units per molecule (number average), ethylene oxide-propylene oxide copolymers, which may have a random, alternating or blocklike structure, having on average from 2 to 50 alkylene oxide units (number average) per molecule, alkylene oxide units being selected from ethylene oxide and propylene oxide, and polytetrahy- drofurans having a molecular weight M _n in the range from 150 to 2,500 g/mol and preferably in the range from 200 to 300 g/mol.

Resin (a) is preferably a melamine derivative, for example a melamine derivative of the general formula IV

where R ¹ to R ⁶ are the same or different and are each defined as follows:

hydrogen or

(CHR ⁸ -O)zR ⁷ , CHR ⁸ -OR ⁷ or CH(OR ⁷ ) ₂ or CH ₂ -N(R ⁷ ) ₂

where z is in the range from 1 to 10 and may but need not be an integer,

and where R ⁷ is in each occurrence the same or different and selected from

hydrogen,

Ci-Ci2-alkyl, branched or unbranched, selected from Ci-Ci2-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec- pentyl, neopentyl, 1 ,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl, n-heptyl, isoheptyl, n-octyl, n-nonyl, n-decyl and n-dodecyl; preferably Ci-Cβ-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1 ,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec- hexyl, more preferably Ci-C4-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl;

alkoxyalkylene such as for example (-CH ₂ -CH ₂ -O)m-H, (-CHCH ₃ -CH ₂ -O)m-H,

(-CH ₂ -CHCH ₃ -O)m-H, (-CH ₂ -CH ₂ -CH ₂ -CH ₂ -O)m-H, where m is an integer from 1 to 20, preferably from 1 to 10 and more preferably from 1 to 5.

R ⁸ is in each occurrence different or preferably the same and selected from

C6-Ci4-aryl and especially phenyl,

Ci-Ci2-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert- butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1 ,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl, n-heptyl, isoheptyl, n-octyl, n-nonyl, n-decyl and n-dodecyl; preferably Ci-Cβ-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1 ,2-dimethylpropyl, isoamyl, n- hexyl, isohexyl, sec-hexyl, more preferably Ci-C4-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl;

and most preferably hydrogen.

The R ¹ , R ³ and R ⁵ radicals are preferably different.

It is more preferable for R ¹ and R ² to be hydrogen and more preferable for R ³ and R ⁴ each to be CH ₂ -OH. It is most preferable for R ¹ and R ² each to be hydrogen and for R ³ to be CH ₂ -OH.

Many melamine derivatives of the general formula I are known per se and are commercially available, for example as Luwipal® from BASF Aktiengesellschaft and as Cymel® 327 from Cytec. Melamine derivatives for the purposes of the present invention are generally not pure in the sense of having one defined formula; typically, one observes intermolecular rearrangements of the R ¹ to R ⁶ radicals, i.e., transacetalization reactions and transaminalization reactions, and also to a certain degree condensation reactions and elimination reactions. The formula V indicated above is to be understood as defining the stoichiometric ratios of the substituents and as comprising intermolecular rearrangement products and condensation products as well.

The melamine derivatives which are most preferably used as resin (a) are obtainable by reaction of melamine with one to three, preferably with 1.4 to 2.8 and more preferably with 1.5 to 2.6 equivalents of at least one aliphatic aldehyde, for example propion- aldehyde, acetaldehyde and especially formaldehyde. This reaction is followed by an etherification with 4.5 to 15 equivalents, preferably up to 10 and more preferably up to 6 equivalents of at least one di- or more highly hydric aliphatic alcohol.

Neither the reaction with aliphatic aldehyde or aliphatic aldehydes nor the etherification need be effected in a stoichiometrically uniform way, so that representation of the melamine derivatives according to the present invention by a formula is not possible. On the contrary, mixtures of various products which continue to be accessible to transaminalization reactions and transetherification reactions are typically obtained.

Melamine derivatives used as resin (a) in the present invention can be prepared in a conventional manner. Melamine derivatives which are particularly preferred for use as resin (a) can be prepared by initially reacting melamine with one to three equivalents of at least one aliphatic aldehyde and then etherifying the reaction product with 4.5 to 10 equivalents of at least one polyhydric aliphatic alcohol.

The reaction of melamine with at least one aliphatic aldehyde in one embodiment of the present invention is carried out in aqueous formulation, preferably at pH values in the range from 7 to 10 and more preferably at pH values in the range from 8 to 9. In another version no water is used and melamine and at least one aldehyde, especially melamine and paraformaldehyde, are mixed and the two reactants are made to react with each other.

In one version the reaction of melamine with at least one aliphatic aldehyde is carried out at temperatures in the range from 50 to 105 ⁰ C and preferably in the range from 70 to 90 ⁰ C.

In one version the reaction of melamine with at least one aliphatic aldehyde is carried out at atmospheric pressure. In another embodiment of the present invention the reac-

tion of melamine with at least one aliphatic aldehyde is carried out at pressures in the range from 1.01 to 50 bar and preferably up to 10 bar.

In one version the reaction of melamine with at least one aliphatic aldehyde is carried out in the presence of at least one catalyst, examples being sodium hydroxide and potassium hydroxide.

In one version the etherification with at least one polyhydric aliphatic alcohol is carried out in aqueous phase at pH values in the range from 1 to 6 and preferably in the range from 5 to 5.5. Desired pH values can be set by addition of an acid such as for example trifluoroacetic acid, methylsulfonic acid, para-toluenesulfonic acid, benzenesulfonic acid, sulfuric acid, phosphoric acid or nitric acid.

In one version the etherification with at least one polyhydric aliphatic alcohol is carried out at temperatures in the range from 20 to 100 ⁰ C and preferably in the range from 30 to 70 ⁰ C.

In one version the etherification with at least one polyhydric aliphatic alcohol is carried out at atmospheric pressure. In another embodiment of the present invention the eth- erification with at least one polyhydric aliphatic alcohol is carried out at pressures in the range from 1.01 to 50 bar.

After the etherification has ended, excess aliphatic aldehyde can be distilled off. It is also possible not to distill off excess aliphatic aldehyde and for excess aliphatic alde- hyde to be removed from the reaction equilibrium by means of suitable reagents, for example oxidizing agents such as nitric acid for example.

In one preferred version the melamine derivatives preferred for use as resin (a) are prepared by omitting distillations between the reaction of melamine with at least one aldehyde and the etherification with at least one polyhydric aliphatic alcohol.

In one embodiment of the present invention melamine derivatives preferred for use as resin (a) are isolated, for example by evaporating any solvents used such as water in particular. Spray drying is a particularly suitable method of isolating melamine deriva- tives used as resin (a) in the present invention.

In another embodiment of the present invention melamine derivatives preferred for use as resin (a) are not isolated but used in the form of dispersions, preferably in the form of aqueous dispersions.

According to the present invention, aqueous pretreatment liquors further comprise at least one thickener (b).

Useful thickeners (b) include natural thickeners such as alginates, polysaccharides, starch, carboxymethylcellulose, guar gum powder and also derivatives thereof, and synthetic thickeners such as if appropriate acrylic acid homo- and copolymers, which may be crosslinked, for example by interpolymerization of at least one compound of the general formula

in each of which R ⁹ is methyl or preferably hydrogen.

Preferred thickeners (b) are associative thickeners of the general formula I, Il and/or III

U-(E)yU Il

U-T-U III

where

E is in each occurrence the same or different and selected from -CH2-CH2-, -CH ₂ -CH(CH ₃ )-, -CH ₂ -CH(C ₂ H ₅ )-,

y is an integer from 1 to 100,000 and preferably in the range from 10 to 10,000,

T is in each occurrence the same or different and a diisocyanate-derived unit,

x is an integer from 1 to 500, preferably in the range from 1 to 2 and more preferably about 1 ,

U is in each occurrence the same or different and selected from units derived from aliphatic or aromatic alcohols, thiols, amines or carboxylic acids each having 4 or more carbon atoms and preferably not less than 6 carbon atoms, aromatic alcohols, thiols, amines or carboxylic acids each having 6 or more carbon atoms, al- cohols, thiols, amines or carboxylic acids having C7-Ci3-aralkyl moieties or het- eroaromatic alcohols, thiols, amines or carboxylic acids.

Associative thickeners of the general formula I are obtainable by reaction of

(i) at least one polyetherdiol with

(ii) at least one diisocyanate and

(Ni) at least one compound of the general formula R ¹⁰ -OH, R ¹⁰ -SH, R ¹⁰ -NH ₂ ,

R ¹⁰ R ¹¹ NH or R ¹⁰ -COOH, where R ¹⁰ and R ¹¹ may be the same or different and are each selected from aliphatic radicals having not less than 4 carbon atoms, aromatic radicals having not less than 6 carbons and heteroaromatic radicals and where R ¹⁰ -OH may be alkoxylated, and also further derivatives of these com- pounds that are capable of forming a urethane, thiourethane or urea bond.

Preferred polyetherdiols (i) for the purposes of the present invention are polyethylene glycol, polypropylene glycol and polytetrahydrofuran, but also copolymers of ethylene oxide and propylene oxide or butylene oxide or terpolymers of ethylene oxide, propyl- ene oxide and butylene oxide, which copolymers may take the form of block copolymers or random copolymers or terpolymers.

Useful diisocyanates (ii) include diisocyanates having NCO groups of the same or a different reactivity. Examples of diisocyanates having NCO groups of the same reactiv- ity are aromatic or aliphatic diisocyanates, preference being given to aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), oc- tamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, trimethylhexane diisocyanate, tetramethyl- hexane diisocyanate, 1 ,4-, 1 ,3- or 1 ,2-diisocyanatocyclohexane, 4,4'-diisocyanatocyclohexylmethane, 1 -isocyanato-S^^-trimethyl-δ-isocyanato- methylcyclohexane (isophorone diisocyanate) and 2,4- and 2,6-diisocyanato- 1-methylcyclohexane, of which hexamethylene diisocyanate and isophorone diisocyanate are particularly preferred. A further particularly preferred diisocyanate is m- tetramethylxylene diisocyanate (TMXDI).

Preferred diisocyanates having NCO groups of differing reactivity are the readily and inexpensively available isocyanates such as for example 2,4-tolylene diisocyanate (2,4-TDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), triisocyanatotoluene as representatives of aromatic diisocyanates or aliphatic diisocyanates, such as 2-butyl- 2-ethylpentamethylene diisocyanate, 2-isocyanatopropylcyclohexyl isocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,4'-methylenebis(cyclohexyl) diisocyanate and 4-methylcyclohexane 1 ,3-diisocyanate (H-TDI).

Further examples of isocyanates having groups differing in reactivity are 1 ,3-phenylene diisocyanate, 1 ,4-phenylene diisocyanate, 1 ,5-naphthylene diisocyanate, diphenyl diisocyanate, toluidine diisocyanate and 2,6-tolylene diisocyanate.

It is naturally also possible to use mixtures of two or more of the aforementioned isocy- anates for synthesis.

Polyisocyanates can be used to a certain extent alongside diisocyanates, for example in amounts of up to 10% by weight based on the total amount of di- and polyisocy- anate. Examples of useful polyisocyanates are biurets and allophanates of HDI or TDI.

Very particularly preferred diisocyanates (ii) are HDI, IPDI, MDI and TDI.

The molar ratio of polyetherdiols (i) to diisocyanates (ii) is generally in the range from 0.3:1 to 1 :1 and preferably about 0.5:1.

The reaction of diisocyanate (ii) with polyetherdiol (i) is typically carried out in the presence of one or more catalysts.

The catalyst or catalysts are preferably used in an amount from 0.01 % to 10% by weight and preferably from 0.05% to 5% by weight, based on diisocyanate (ii).

Useful catalysts to speed especially the reaction between the NCO groups of diisocy- anate (ii) and the hydroxyl groups of polyetherdiol (i) are well-known tertiary amines, for example triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N, N'- dimethylpiperazine, 2-dimethylaminoethoxyethanol, 1 ,4-diazabicyclo[2.2.2]octane (DABCO) and the like and also in particular organic metal compounds such as titanate esters, iron(lll) acetylacetonate, tin compounds, for example tin diacetate, tin dioc- tanoate, tin dilaurate or the dialkyl derivatives of tin dialkyl salts of aliphatic carboxylic acids such as dibutyltin diacetate, dibutyltin dilaurate or the like.

The synthesis of the associative thickeners (b) is generally carried out without a solvent or in an aprotic solvent, with a suitable solution being in principle any solution which reacts neither with polyurethane nor with polyetherdiol (i) nor with diisocyanate (ii), for example tetrahydrofuran, diethyl ether, diisopropyl ether, chloroform, dichloromethane, di-n-butyl ether, acetone, N-methylpyrrolidone (NMP), xylene, toluene, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK) or 1 ,4-dioxane. Preferred reaction temperatures are in the range from -20 ⁰ C to the boiling point of the solvent used. The reac- tion is generally carried out under atmospheric pressure, but it may also be carried out in autoclaves at up to 20 bar.

Reacting NCO-terminated products of polyetherdiol (i) with diisocyanate (ii) with aliphatic or aromatic alcohols, thiols, primary or secondary amines or carboxylic acids (iii) converts the reaction products of the components (i) and (ii), which comprise free iso- cyanate groups, into hydrophobicized products.

Suitable are in particular alcohols R ¹⁰ -OH and primary or secondary amines R ¹⁰ -NH2 and R ¹⁰ R ¹¹ NH, in each of which R ¹⁰ and R ¹¹ may be the same or different and are each selected from

C4-C6o-alkyl such as for example n-butyl, isobutyl, n-pentyl, preferably C6-C4o-alkyl such as for example n-hexyl and n-heptyl and especially C8-C4o-alkyl such as for example n- octyl, n-nonyl, n-decyl, n-dodecyl, n-hexadecyl or n-eicosyl;

C6-Ci4-aryl such as phenyl, α-naphthyl, β-naphthyl, 1-anthracenyl, 2-anthracenyl or 9- anthracenyl

heteroaromatic radicals such as α-pyridyl, β-pyridyl, γ-pyridyl, N-pyrryl, β-pyrryl, γ- pyrryl, porphyrinyl, 2-furanyl, 3-furanyl, 2-thiophenyl, 3-thiophenyl, N-pyrazolyl, N- imidazolyl, N-triazolyl, N-oxazolyl, N-indolyl, N-carbazolyl, 2-benzofuranyl, 2- benzothiophenyl, N-indazolyl, benzotriazolyl, 2-quinolinyl, 3-isoquinolinyl and α- phenanthrolinyl;

C7-Ci3-aralkyl, preferably C7- to Ci2-phenylalkyl such as benzyl, 1-phenethyl, 2- phenethyl, 1-phenylpropyl, 2-phenylpropyl, 3-phenylpropyl, neophyl (1-methyl-1- phenylethyl), 1-phenylbutyl, 2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, more preferably benzyl.

Alcohols R ¹⁰ -OH may also have been alkoxylated with one or more equivalents of ethylene oxide, propylene oxide or butylene oxide, in which case not only homo- but also (block) copolymers of the identified alkylene oxides can be used, typically having about 20 to 500 alkylene oxide units. Alcohols R ¹⁰ -OH may further be alkoxylated with THF.

In general, the compound of the general formula R ¹⁰ -OH, R ¹⁰ -SH, R ¹⁰ -NH ₂ , R ¹⁰ R ¹¹ NH or R ¹⁰ -COOH (iii) is used with regard to the free isocyanate groups in an at least stoichiometric amount, but frequently in stoichiometric excess, for example from 50 to 100 mol%, based on free NCO groups.

Hydrophobic groups R ¹⁰ may also be attached to polyetherdiol (i) via an ester or ether bridge. Associative thickeners of the general formula Il are thus obtainable for example by reaction of

polyetherdiols (i) with

one or more compounds of the general formula R ¹⁰ -OH or R ¹⁰ -COOH, where R ¹⁰ has the above-identified meanings, or further derivatives of these compounds that are capable of forming an ether or ester bond.

Associative thickeners of the formula III are obtained for example from diisocyanate (ii) and at least one compound of the general formula R ¹⁰ -OH, R ¹⁰ -SH, R ¹⁰ -NH ₂ , R ¹⁰ R ¹¹ NH or R ¹⁰ -COOH (iii) without polyetherdiols (i) being present. In this reaction, the compound of the general formula R ¹⁰ -OH, R ¹⁰ -SH, R ¹⁰ -NH ₂ , R ¹⁰ R ¹¹ NH or R ¹⁰ -COOH (iii) or to be more precise the compounds (iii) may be used in stoichiometric excess, based on diisocyanate (ii).

To practice step (A) of the process of the present invention, substrates from polypropylene are first treated with at least one aqueous pretreatment liquor comprising the above-described components (a) and (b). To treat a substrate from polypropylene with an aqueous pretreatment liquor comprising the above-described components (a) and (b), hereinafter also simply referred to as aqueous pretreatment liquor, the substrate from polypropylene is contacted at least once with aqueous pretreatment liquor and subjected to the action thereof for a certain period, for example for a period in the range from 0.1 second to 2 hours, and is subsequently removed as pretreated substrate. Contacting can be effected in various ways. It is possible for example to apply inventive aqueous pretreatment liquor to textile substrate, for example by exhaust processes or batch or continuous processes involving forced application.

There are various versions of an exhaust process that are known as such from the field of textile dyeing. For example, the textile substrate can be in a wound-up state and aqueous pretreatment liquor forced under pressure through the wound-up textile substrate, in which case the aqueous pretreatment liquor can flow from in to out or else, in fully flooded machines, from out to in. To ensure uniform application, at least one change in the direction of flow of aqueous pretreatment liquor during the pretreatment is advantageous. In another embodiment, substrate from polypropylene is present in an unconstrained state in the aqueous pretreatment liquor and moves therewith. In a further embodiment, substrate from polypropylene can be pulled through a standing bath comprising an aqueous pretreatment liquor. Advantageously, substrate from polypro- pylene is repeatedly pulled through an aqueous pretreatment liquor and the direction of movement of the substrate from polypropylene should reverse. This is useful for uniform application. More particular details concerning these application processes can be found in the relevant literature, for example Veredlung von Textilien, VEB Fachbuch- verlag Leipzig, 1 st edition 1976, pages 93 ff.

Useful continuous processes for application include all processes whereby the aqueous pretreatment composition can be applied uniformly or imagewise. Of particular suitability here are all printing processes and also all processes in which the substrate from polypropylene is uniformly drenched with an aqueous pretreatment liquor. The difference to exhaust processes is that a forced application is realized. The aqueous pretreatment liquor need not have any affinity for fiber for these processes.

Useful printing processes for the application of an aqueous pretreatment liquor include for example all screen printing processes. Screen printing processes are important processes which are known in principle and are utilized inter alia in the production of printed fabrics. In screen printing, the aqueous pretreatment liquor is forced by a squeegee through a fine mesh and onto a substrate from polypropylene to be pre- treated. The mesh can be formed from synthetic fibers, as in flat screen printing machines, or metals, as in rotary screen printing machines.

Relief printing, gravure printing or roller printing, being common printing processes, are also useful for applying inventive aqueous pretreatment liquor. Details concerning individual printing processes can be found on pages 1 10 ff. of the literature reference cited above.

Next to printing processes, however, it is also possible to use any technique wherein any substrate from polypropylene is uniformly drenched with an aqueous pretreatment liquor. This can be accomplished for example using pad-mangle technology wherein substrate from polypropylene is led through a trough filled with aqueous pretreatment liquor and subsequently squeezed off by two rolls to a defined wet pickup. It is also possible to lead substrate from polypropylene through a nip formed between two rotat- ing rollers and filled with aqueous pretreatment liquor. The rollers lead to an intensive contacting of substrate from polypropylene with aqueous pretreatment liquor while at the same time squeezing off the substrate from polypropylene to the desired wet pickup. There are in addition many other possible configurations for this pad-mangle technology, which are all likewise useful for applying an aqueous pretreatment liquor.

Defined amounts of aqueous pretreatment liquor can be applied by well-known spraying and pouring techniques.

In one embodiment of the present invention substrate from polypropylene is contacted with sufficient pretreatment liquor to apply from 0.1 to 30 g of solids/m ² of substrate from polypropylene, preferably from 1 g/m ² to 25 g/m ² and more preferably up to 15 g/m ² .

In one embodiment of the present invention the temperature chosen for the pretreat- ment liquor is in the range from 20 ⁰ C to 60 ⁰ C.

To proceed by pad-mangle technology, the rolls may be set to a nip pressure in the range from 2 to 3 bar for example.

In one embodiment of the present invention aqueous pretreatment liquors comprise (a) from 0.1 % to 20%, preferably from 0.1 % to 15% by weight and more preferably from 0.1 % to 10% by weight of at least one resin selected from melamine deriva-

tives, dimethyloldihydroxyethyleneurea (DMDHEU) and derivatives of DMDHEU,

(b) from 0.1 % to 30% by weight of thickener,

(c) from 0.1 % to 50% by weight of polycationic compound, and

(d) from 0% to 30% by weight of additives.

The solids content of pretreatment liquors may be for example in the range from 10 g/l to 600 g/l and preferably in the range from 50 g/l to 500 g/l.

In one embodiment of the present invention the contacting of substrate from polypro- pylene with aqueous pretreatment liquor may be followed by drying, for example to a residual moisture content in the range from 5% to 30% by weight.

This may be accomplished by heating substrate from polypropylene which has been contacted with an aqueous pretreatment liquor such that water present can evaproate fully or partially. It is preferable to employ temperatures in the range from 80 to 100 ⁰ C. The heat needed can be introduced in the form of heated air as a heat transfer agent. But it is also possible to use infrared radiators or microwave radiators. Preferably, the substrate from polypropylene is kept under tension in the drying operation in order that the formation of creases may be avoided.

In one embodiment of the present invention one or more salts of mono- or bivalent metals or ammonium salts may be added to pretreatment liquor. Examples of useful salts are ZnCb, Zn(NOs)2, each in its hydrated or nonhydrated form, NH ₄ CI, (NH ₄ ^SO ₄ , NaBF ₄ , AlCh-θ H2O, ammonium dihydrogen phosphate, diammonium hydrogen phos- phate, and most preferably MgCb, for example in the form of its hexahydrate.

When inventive pretreatment liquors comprise one or more salts of mono- or bivalent metals or ammonium salts, the amounts will typically be in the range from 0.1 % to 30% by weight, based on resin (a), preferably in the range from 0.5% to 10% and more preferably in the range up to 8% by weight.

Step (B) of the process according to the present invention comprises printing pre- treated and if appropriate dried substrate from polypropylene, preferably by the ink jet process.

The ink jet process utilizes inks, which may be solvent or preferably water borne, that are sprayed as small droplets directly onto the substrate from polypropylene. There is a continuous form of the process, in which the ink is pressed at a uniform rate through a nozzle and the jet is directed onto the substrate by an electric field depending on the pattern to be printed, and there is an interrupted ink jet or drop-on-demand process, in which the ink is expelled only where a colored dot is to appear, the latter form of the process employing either a piezoelectric crystal or a heated hollow needle (bubble jet

process) to exert pressure on the ink system and so eject the ink droplets. These techniques are described in Text. Chem. Color, volume 19 (8), pages 23 to 29, 1987, and volume 21 (6), pages 27 to 32, 1989.

The ink jet inks used for printing substrates from polypropylene in the process of the present invention, as well as one or more dispersants, typically comprise water or water-solvent mixture and also finely divided organic or inorganic colorants which are preferably substantially insoluble in water or in the water-solvent mixture, examples being pigments as defined in German standard specification DIN 55944. Disperse dyes can be used instead of pigments. But ink jet inks can also comprise direct dyes, acid dyes, reactive dyes or vat dyes as dissolved dyes. The soluble dyes mentioned can be present as brightening agents in pigment-based ink jet inks, in which case soluble dyes (especially direct, acid or reactive dyes) which are similar in hue to the pigment are used.

Step (B) is particularly preferably carried out using at least one pigment-based ink jet ink which, as well as at least one pigment and water, comprises at least one dispers- ant.

Useful dispersants include for example those based on maleic acid-acrylic acid copolymers, especially those having an M _n molecular weight in the range from 2 000 to 10 000 g/mol, which are useful in the form of random copolymers or block copolymers. Useful dispersants further include N-vinylpyrrolidone homopolymers and acrylate-N- vinylpyrrolidine copolymers, especially N-vinylpyrrolidone homopolymers and acrylate- N-vinylpyrrolidine copolymers having an M _n molecular weight in the range from 2,000 to 10,000 g/mol, in the form of random copolymers or block copolymers.

Useful dispersants also include those based on naphthalenesulfonic acid-formaldehyde condensates, for example according to US 5,186,846, or based on alkoxylated styry- lated and optionally sulfated alkylphenols or bisphenols for example according to US 4,218,218.

Useful dispersants further include random polyurethane copolymers as disclosed for example in WO 2004/31255 page 3 ff.

Ink Jet inks used in step (B) preferably comprise at least one solvent having a boiling point above 110 ⁰ C, examples being ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, glycerol, diglycerol, propylene glycol, dipropylene glycol, room temperature liquid polytetrahydrofuran, 1 ,3-propanediol, mono-, di- or triethylene glycol mono-Ci-C4-alkyl esters in each of which Ci-C4-alkyl is selected from methyl, ethyl, n- propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl.

In one embodiment of the present invention, ink jet inks used in step (B) have a dynamic viscosity in the range from 1 to 30 mPa-s, preferably in the range from 1 to 20 mPa-s and more preferably in the range from 2 to 15 mPa-s, in each case determined at 20 ⁰ C.

In one embodiment of the present invention, ink jet inks used in step (B) have a surface tension in the range from 20 to 70 mN/m, especially in the range from 20 to 40 mN/m and more preferably in the range from 25 to 35 mN/m, all determined at 20 ⁰ C.

The pH of ink jet inks used in step (B) is generally in the range from 5 to 10 and preferably in the range from 7 to 9.

Ink jet inks used in step (B) may comprise further auxiliaries of the kind customary especially for aqueous ink jet inks and in the printing and coatings industry. Examples of such auxiliaries include erythritol, pentaerythritol, pentitols such as arabitol, adonitol and xylitol and hexitols such as sorbitol, mannitol and dulcitol. Further examples are polyethylene glycols having an M _w in the range from more than 2,000 g/mol to about 10,000 g/mol and preferably up to 8,000 g/mol. Further examples are preservatives such as for example 1 ,2-benzisothiazolin-3-one and its alkali metal salts, degas- sers/defoamers such as for example ethoxylated acetylenediols, which typically comprise from 20 to 40 mol of ethylene oxide per mole of acetylenediol and may also have a dispersing effect, viscosity regulators, flow agents, wetters (examples being wetting surfactants based on ethoxylated or propoxylated fatty or oxo alcohols, propylene ox- ide-ethylene oxide block copolymers, ethoxylates of oleic acid or alkylphenols, alkyl- phenol ether sulfates, alkylpolyglycosides, alkylphosphonates, alkylphenylphospho- nates, alkyl phosphates, alkylphenyl phosphates, or preferably polyethersiloxane copolymers, especially alkoxylated 2-(3-hydroxypropyl)nonamethyltetrasiloxanes and alkoxylated 2-(3-hydroxypropyl)heptamethyltrisiloxanes, which generally have a block of 7 to 20 and preferably 7 to 12 ethylene oxide units and a block of 2 to 20 and pref- erably 2 to 10 propylene oxide units and may be present in the colorant preparations in amounts from 0.05% to 1 % by weight), anti-settlers, luster improvers, lubricants, adhesion promoters, anti-skinning agents, delusterants, emulsifiers, stabilizers, hydrophobi- cizers, light control additives, antistats, bases such as for example K2CO3 or acids, specifically carboxylic acids such as for example lactic acid or citric acid to regulate the pH. When these agents are part of ink jet inks used in step (B), their total amount will generally be 2% by weight and especially 1 % by weight, based on the weight of the colorant preparations of the present invention and especially of the ink jet process inks of the present invention.

In one embodiment of the present invention, no hand improvers need be added to the ink jet inks used in step (B).

Inks used in step (B) may comprise one or more resins (a) in amounts of up to 10% by weight.

After having performed step (B), a substrate from propylene is obtained which is briefly referred to as printed substrate in the context of the present invention.

In step (C) of the process of the present invention, printed substrate is aftertreated with an aqueous formulation comprising at least one binder.

Binders in the context of the present invention are film-forming (co)polymers or pre- polymers. In one embodiment of the present invention, binders are selected from acry- late binders and polyurethane binders.

Preferably, binders are selected from film-forming (co)polymers which have a glass transition temperature above -50 ⁰ C, preferably from -25°C up to 150 ⁰ C and even more preferably up to +30 ⁰ C. Glass transition temperatures can be calculated according to the Fox equation or be determined experimentally with methods known as such, e.g., DSC (Differential Scanning Calorimetry).

Acrylate binders in the context of the present invention can be selected from copolymers of at least one ethylenically unsaturated acid such as maleic acid, fumaric acid, E- and Z- crotonic acid, itaconic acid and particularly (meth)acrylic acid with at least one comonomer selected from monovinylaromatic compounds, Ci-Cio-alkyl esters of monoethylenically unsaturated carboxylic acids, monoethylenically unsaturated carboxamides, polyfunctional derivatives of ethylenically unsaturated carboxylic acids, and preferably at least one additional comonomer having at least one epoxy group, NH-CH2OH group or acetoacetyl group per molecule.

Examples of particularly suitable monovinylaromatic compounds are -methylstyrene, para-methylstyrene, 2,4-dimethylstyrene and especially styrene.

Particularly suitable Ci-Cio-alkyl esters of monoethylenically unsaturated carboxylic acids are esters of branched or unbranched Ci-Cio-alkanol with one of the aforementioned monoethylenically unsaturated carboxylic acids. Specific examples are: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate.

Particularly suitable monoethylenically unsaturated carboxamides are N-methylacrylamide, N-methylmethacrylamide, N-ethylacrylamide,

N-ethylmethacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide and especially acrylamide and methacrylamide.

Particularly suitable polyfunctional derivatives of ethylenically unsaturated carboxylic acids are compounds of the general formula Vl

where

X ¹ and X ² are the same or different and selected from oxygen, NH and N-R ¹¹ ,

A is a spacer, for example branched or unbranched C2-C2o-alkylene or phenylene.

Examples of C ₂ -C ₂ o-alkylene are -(CH ₂ ) ₂ -, -CH ₂ -CH(CH ₃ )-, -(CH ₂ ) ₃ -, -CH ₂ -CH(C ₂ H ₅ )-, -(CH ₂ ) ₄ -, -(CH ₂ ) ₅ -, -(CH ₂ ) ₆ -, -(CH ₂ ) ₇ -, -(CH ₂ ) ₈ -, -(CH ₂ ) ₉ -, -(CH ₂ )io-; preferably C ₂ -C ₄ -alkylene; especially -(CH ₂ ) ₂ -, -CH ₂ -CH(CH ₃ )-, -(CH ₂ ) ₃ -, -(CH ₂ ) ₄ - and -CH ₂ -CH(C ₂ H ₅ )-.

R ¹² and R ¹³ are the same or different and selected from Ci-Cio-alkyl, for example methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, iso-pentyl, sec-pentyl, neopentyl, 1 ,2-dimethylpropyl, iso-amyl, n-hexyl, iso-hexyl, sec-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, more preferably unbranched Ci-C ₄ -alkyl such as methyl, ethyl, n-propyl and n-butyl.

Particularly suitable comonomers having epoxy groups are for example glycidyl esters of maleic acid, fumaric acid, E- and Z- crotonic acid and especially of acrylic acid and of methacrylic acid.

Particularly suitable comonomers having NH-CH ₂ OH groups are for example reaction products of formaldehyde with monoethylenically unsaturated carboxamides, especially N-methylolacrylamide and N-methylolmethacrylamide.

Particularly suitable comonomers having acetoacetyl groups are for example (meth)acrylates of alcohols of the general formula VII

where

R ¹⁴ is selected from branched or unbranched Ci-Cio-alkyl, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, iso-pentyl, sec-pentyl, neopentyl, 1 ,2-dimethylpropyl, iso-amyl, n-hexyl, iso-hexyl, sec-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, more

preferably unbranched Ci-C4-alkyl such as methyl, ethyl, n-propyl and n-butyl.

Film forming (co)polymers can be manufactured in a conventional manner, for example by emulsion polymerization with one or more free-radical starters in the presence of one or more emulsifiers. Particular preference is given to preparing film forming (co)polymers by an emulsion polymerization in seeded mode; that is, initially one or more water-insoluble polymers such as for example polystyrene are added in very small particles, for example having an average diameter in the range from 15 to 30 nm, which then promote droplet formation during the copolymerization.

One embodiment of the present invention comprises film forming (co)polymer having a dynamic viscosity in the range from 10 to 200 mPa-s, determined by the Brookfield method for example, at room temperature.

One embodiment of the present invention comprises film forming (co)polymer having in an amount from 0.1 % to 7% by weight of the total amount of binder.

Examples for suitable polyurethane binders are polyurethanes, preferably hydroxyl terminated polyurethanes, made from at least one aliphatic or aromatic or cycloaliphatic di- or polyisocyanate or a mixture thereof, and at least one diol selected from hydroxyl-terminated polyesters or diols or polyols.

Suitable di- and polyiocyanates are 2,4- and 2,6-toluylene diisocyanate and mixtures of the foregoing (TDI), tetramethylenediisocyanate, hexamethylenediisocyanate (HDI), dodecamethylenediisocyanate, 1 ,4-cyclohexane-diisocyanate, 4,4'- dicyclohexylmethylene diisocyanate (MDI), isophorone diisocyanate (IPDI) and and mixtures thereof.

Preferred hydroxyl-terminated polyesters are made from at least one aliphatic or ali- cyclic (cycloaliphatic) diol, such as ethylene glycol, neopentylglycol (2,2- dimethylpropane 1 ,3-diol), dimethylol-1 ,4-cyclohexane, 1 ,4-butanediol, 1 ,6-hexanediol, 1 ,12-dodecanediol.

Preferred polyurethane binders can bear an acid group such as a carboxyl group or a sulfonate group. Acid group bearing polyurethanes can be made by, e.g., by carrying out the synthesis of the respective polyurethane in the presence of a diol or a diamine with primary or secondary amino groups and with a free carboxyl group or sulfonate group. Suitable examples are 3,3-dimethylolpropanoic acid and 2-(2-aminoethyl) amino ethanesulfonic acid monoalkalimetall salt, in particular the respective sodium salt (see below).

In one embodiment of the present invention, aqueous formulation employed in step (C) also contains at least one fixing agent. Thus, the aftertreatment step can be performed by additionally using a fixing agent, in the context of the present invention also referred to as fixing agent (e).

Suitable fixing agents can be selected from di- or polyisocyanates such as hexame- thylene diisocyanate. Di- and polyisocyanates are preferred fixing agents when using a polyurethane binder in step (C).

Suitable fixing agents (e) can further be selected from

(e1) melamine which can be alkoxylated, alkoxyalkylated or converted to seminami- nals, (e2) non-hydrophilized and hydrophilized isocyanurates,

(e3) polyglycidyl ethers having 2 to 5 glycidyl groups per molecule,

(e4) carbodiimides,

(e5) urea or urea derivatives which may if appropriate have been aminalized or hemi- aminalized.

Examples of melamine derivatives (e1) are optionally alkoxylated or alkoxyalkylated compounds or hemiaminalized melamines especially of the general formula VIII

in each of which the variables are defined as follows:

R ¹⁵ , R ¹⁷ and R ¹⁹ are different or preferably the same and are each selected from

CH ₂ -OH, CH ₂ -O-R ²¹ or most preferably hydrogen,

R ¹⁶ , R ¹⁸ and R ²⁰ are each identically or differently selected from CH ₂ -OH, CH ₂ -O-R ²¹ or hydrogen, although preferably at least one of the R ¹⁵ to R ²⁰ variables being other than hydrogen, R ²¹ is in each occurrence the same or different and selected from

Ci-C ₄ -alkyl, for example ethyl, n-propyl, n-butyl, isopropyl and especially methyl, (CH ₂ CH ₂ O) _m -H where m is selected from integers in the range from 1 to 25.

A particularly preferred embodiment of the present invention utilizes such melamine derivatives of the general formula VII as have from three to five of the R ¹⁵ to R ²⁰ variables equal to hydrogen and from one to three of the R ¹⁵ to R ²⁰ variables selected from CH2-O-R ²¹ , where m is an integer from 1 to 3.

Melamine derivatives of the general formula VIII are known per se. Melamine derivatives of the formula VII are generally not present pure in the sense of conforming to one defined formula; it is customary to observe intermolecular rearrangements, i.e., trans- acetalization reactions and trans-aminalization reactions, and also to some extent con- densation reactions and elimination reactions. The above-indicated formula VII is to be understood as defining the stoichiometric ratios of the variables of the R ¹⁵ to R ²⁰ radicals and as also encompassing intermolecular rearrangement products and condensation products.

Examples of non-hydrophilized and hydrophilicized isocyanurates (e2) are iso- cyanurates for example of the general formula IX

in each of which the R ²² variables are different or preferably the same and represent for example (CHb) _n -NCO, where n is an integer in the range from 2 to 20 and preferably from 4 to 12, very particular preference being given to all R ²² variables being the same and n representing 6, and which - in the case of the hydrophilized isocyanurates - may have been reacted with from one to three equivalents of polyalkylene oxides such as for example polypropylene oxide or preferably polyethylene oxide.

Examples of polyglycidyl ethers (e3) having from 2 to 5 glycidyl groups per molecule and preferably from 2 to 4 glycidyl groups per molecule are pentaerythrityl triglycidyl ether and glyceryl 1 ,3-diglycidyl ether and mixtures thereof.

Examples of carbodiimides (e4) are dicyclohexylcarbodiimide and also the systems described in the patent applications EP-A 1 002 001 , DE-A 199 54 500 and DE-A 100 00 656.

Examples of urea or urea derivatives (e5), which may if appropriate be converted to aminals or hemiaminals, are: unmodified or multiply, especially singly, doubly, triply or quadruply, alkylolated, especially methylolated and also alkoxyalkylolated, and especially methoxymethylolated urea compounds and their di-, tri- and tetramers or oli-

gomeric or polymeric, linear, branched or cyclic precondensates. Also alkylolated urea compounds as di-/tri-tetrameric or oligomeric or polymeric, linear or branched or cyclic addition/condensation products of urea and multiply functional alkylaldehydes, especially glyoxal and their alkoxylated and especially methoxylated compounds.

In one embodiment of the present invention, fixing agent (e) is identical to resin (a). In another embodiment, fixing agent (e) is different from resin (a).

Aqueous formulations used in step (C) of the present invention may have a solids content in the range from 10% to 70% by weight and preferably in the range from 30% to 50% by weight.

To practice step (C) of the present invention, the wet pickup may be chosen such that step (C) results in a wet pickup in the range from 25% by weight to 200% by weight and preferably in the range from 60% to 190% by weight.

The temperature for practicing step (C) of the present invention is in itself not critical. The temperature may be in the range from 10 to 60 ⁰ C and preferably in the range from 15 to 30 ⁰ C.

Preferably aqueous formulation used in step (C) may have a pH in the range from 2 to 9, and preferably in the range from 3.5 to 7.5.

Step (C) of the present invention is in one embodiment of the present invention carried out in common machines used for the finishing of textiles, for example pad-mangles or foulards. Preference is given to vertical textile feed pad-mangles or foulards, where the essential element is two rollers in press contact with each other, through which the printed substrate is led. The aqueous formulation containing at least one binder is filled in above the rollers and wets the printed substrate. The pressure causes the printed substrate to be squeezed off and ensures a constant add-on. In other preferred pad- mangles or foulards, printed substrate is first led through a dip bath and then upwardly through two rolls in pressed contact with each other. In the latter case, the pad- mangles (foulards) are also said to have a vertically upward textile feed. Pad-mangles and foulards are described for example in Hans-Karl Rouette, ^" Handbuch der Textilveredlung ^" , Deutscher Fachverlag 2003, pages 618 to 620.

Aftertreatment in accordance with the present invention may also be accomplished for example by single or multiple spraying, bedrizzling, overpouring or printing.

Aqueous formulations for the purposes of the present invention may - in addition - comprise one or more organic solvents, for example alcohols such as methanol, ethanol, isopropanol, ethylene glycol, diethylene glycol, triethylene glycol, acetone,

methyl ethyl ketone, methyl isobutyl ketone, ethylene glycol mono-n-butyl ether, ethylene glycol monoisobutyl ether, acetic acid, n-butanol, isobutanol, n-hexanol and isomers, n-octanol and isomers, n-dodecanol and isomers. Organic solvents may comprise from 1 % to 40% by weight and preferably from 2% to 25% by weight of the continuous phase of aqueous formulation used in accordance with the present invention. The term "aqueous formulations" is to be understood as referring to such formulations where the continuous phase consists predominantly or, at the extreme, exclusively of water.

The aftertreated substrate from polypropylene can be dried after having performed step (C). Drying may be accomplished for example at temperatures in the range from 20 to 120 ⁰ C.

Drying may be carried out at atmospheric pressure for example. It may also be carried out at reduced pressure, for example at a pressure in the range from 1 to 850 mbar.

Drying may utilize a heated or unheated stream of gas, in particular a heated or unheated stream of an inert gas such as nitrogen for example. To utilize a heated stream of gas, suitable temperatures range for example from 30 to 200 ⁰ C, preferably from 120 to 150°C.

Step (C) and the drying operation may be followed by a thermal treatment, also referred to as tempering in the context of the present invention, as a continuous operation or as a batch operation. The duration of the tempering treatment can be chosen within wide limits. The tempering treatment can typically be carried out for a duration in the range from about 1 second to 30 minutes and especially up to 3 minutes. A tempering treatment is carried out by heating to temperatures of 120 ⁰ C up to 180 ⁰ C, preferably in the range from 150 to 170 ⁰ C. It is of course necessary to adapt the temperature of the tempering treatment to the sensitivity of the material of which the surface is made that has been treated according to the present invention.

Hot air drying is an example of a specific suitable method of tempering.

In one embodiment of the present invention, substrate from polypropylene is (A) pretreated with at least one aqueous pretreatment liquor comprising

(a) at least one resin selected from melamine derivatives, dimethyloldihydroxy- ethyleneurea (DMDHEU) and derivatives of DMDHEU,

(b) at least one thickener,

(c) optionally at least one polycationic compound, and (d) optionally at least one additive,

(B) printed by the ink jet process, and thereafter

(C) aftertreated with an aqueous formulation containing at least one binder.

Resins (a) and thickeners (b) are each as defined above.

Aqueous pretreatment liquors may comprise one or more polycationic compounds as component (c).

Useful polycationic compounds include for example cationic homopolymers or copolymers. Preferred polycationic compounds are polyvinylamines, for example having Fikentscher K values in the range from 15 to 60, polyethylenimines, for example having an M _n molecular weight in the range from 5,000 to 1 ,000,000 g/mol, homo- or copoly- mers of diallyldialkylammonium monomers, such as diallyldimethylammonium chloride, cationic acrylates and acrylamides such as acryloyloxyethyldimethylammonium chloride or acrylamidoethyldimethylammonium chloride, quaternary vinylpyridines such as methylvinylpyridine chloride, polyalkylamine polymers and copolymers, also polyal- lylamine hydrochloride, allylamine hydrochloride-diallylamine hydrochloride copolymer, N-vinylacryloylamidine hydrochloride-acrylamide copolymer, dialkylamine- epichlorohydrin polymer, polyamide-polyamine-epichlorohydrin polymer, dicyandia- mide-formaldehyde polycondensate, polyethylenepolyamine-dicyandiamide polycon- densate, polyethyleneimine hydrochloride, poly(meth)acryloyloxyalkyldialkylamine hydrochloride, (meth)acryloyloxyalkyldialkylamine hydrochloride-acrylamide copolymer and poly(meth)acryloyloxyalkyltrialkylammonium chloride.

Preferred polycationic compounds (c) are homo- or copolymers of diallyldialkylammonium monomers, such as polydiallyldimethylammonium chloride (poly DAD MAC), polydiallyldiethylammonium chloride (polyDADEAC), polydiallyldimethylammonium bromides (polyDADMABs), polydiallyldiethylammonium bromide (polyDADEAB), particular preference is given to polymers or copolymers of diallyldimethylammonium chloride and especial preference is given to diallyldimethylammonium chloride homopoly- mer (polyDADMAC).

Copolymers of the monomers mentioned may also comprise nonionic monomers, for example vinylpyrrolidone, (partially saponified) vinyl acetate or hydroxy(meth)acrylate, as interpolymerized comonomers.

Processes for preparing diallyldialkylammonium homo- or copolymers are described for example in US 4,742,134, US 5,283,306 and EP-A 0 264 710.

In a particularly preferred embodiment, aqueous pretreatment liquors comprise polymers or copolymers of diallyldialkylammonium monomers, especially diallyldimethylammonium chloride homopolymer, as polycationic compounds (C), at least one mela- mine derivative as resin (a) and one or more associative thickeners of the formula I, Il and/or III as thickeners (b).

As well as said components (a), (b) and (c), aqueous pretreatment liquors may comprise additives as a component (d). Additives are for example aldehyde scavengers, defoamers, emulsifiers, solvents, biocides, deaerators and wetting agents.

Useful aldehyde scavengers include for example urea and carbamates.

Useful defoamers include for example silicone defoamers such as for example those of the formula HO-(CH2)3-Si(CH3)[OSi(CH3)3]2. Silicone-free defoamers are also suitable, examples being multiply alkoxylated alcohols, for example fatty alcohol alkoxylates, preferably 2- to 50-tuply ethoxylated preferably unbranched Cio-C2o-alkanols, un- branched Cio-C2o-alkanols and 2-ethylhexan-1-ol.

Useful emulsifiers include for example cationic, anionic, zwitterionic and nonionic surfactants. Nonionic surfactants are particularly useful, examples being multiply and es- pecially 5- to 10O-tuply alkoxylated fatty alcohols.

Useful biocides (also known as preservatives) include for example 1 ,2- benzisothiazolin-3-one ("BIT") (commercially available as Proxel® brands from Avecia Lim.) and its alkali metal salts; useful biocides also include 2-methyl-2H-isothiazole-3 ("MIT") and 5-chloro-2-methyl-2H-isothiazol-3-one ("CIT").

Useful deaerators are for example those based on polyethersiloxane copolymers, for example H-(EO)a-O-(CH2)3-Si(CH3)[OSi(CH3)3]2, where a for example represents an integer in the range from 1 to 10 and EO represents OCH2CH2.

Useful wetting agents include for example nonionic, anionic or cationic surfactants, especially ethoxylation and/or propoxylation products of fatty alcohols or propylene oxide-ethylene oxide block copolymers, ethoxylated or propoxylated fatty or oxo alcohols, also ethoxylates of oleic acid or alkylphenols, alkylphenol ether sulfates, alkyl- polyglycosides, alkyl phosphonates, alkylphenyl phosphonates, alkyl phosphates or alkylphenyl phosphates.

A further aspect of the present invention comprises substrates from polypropylene obtainable by the present invention's process described above. Inventive substrates from polypropylene are notable not only for particular brilliance of the color and the contours and particularly good adhesion and hence fastness of the print, for example for particularly good rubfastnesses, wetrubfastnesses and washfastnesses, even after repeated bending or folding, but also for a particularly pleasant hand.

The invention is illustrated by working examples.

Preparation of melamine derivatives used according to invention

1.1. General procedure illustrated by reference to a melamine derivative a.1 formed from melamine formaldehyde:diethylene glycol 1 :2.2:5 (molar ratios)

1 15.5 g of a 40% by weight aqueous formulation of formaldehyde (1.54 mol) were placed in a 1 I three neck flask equipped with dropping funnel and stirrer and adjusted to pH 8.5 with 25% by weight aqueous NaOH. Melamine (88.2 g, 0.7 mol) was subsequently added as a solid before heating to 80 ⁰ C for 30 min, whereafter diethylene glycol (371.3 g, 3.5 mol) was added dropwise before the pH was adjusted to 5.3 with 30% by weight of aqueous HNO3. The resulting solution was heated to 6O ⁰ C for 1 h. The pH was subsequently adjusted to 8 with 25% by weight NaOH. About 80 ml of a mixture of water and diethylene glycol were subsequently distilled off at 100 mbar and 100 ⁰ C to leave melamine derivative a.1.

Analysis: nonvolatiles: 42.5% by weight (determined by 2 h drying in a drying cabinet at 120°C), H ₂ O by Karl Fischer: 3.7% by weight, dynamic viscosity η: 850 mPa-s, determined using a plate-cone viscometer.

1.2 Preparation of further melamine derivatives used according to invention Prescription 1.1 was repeated except that the amounts of formaldehyde and diethylene glycol or methanol according to table 1 were added.

Table 1 : Preparation of melamine derivatives used according to invention

n.d.: not determined

Abbreviations: Non-v.: nonvolatiles (determined by 2 h drying in a drying cabinet at 120 ⁰ C), DEG: diethylene glycol. η: determined at 23°C

Production of pretreatment liquors and binders

1.1 Production of pretreatment liquors

Component (a): melamine derivative as per table 1 or 2 Component (b): b.1 , see hereinbelow Component (c): c.1 or c.2, see hereinbelow.

To produce 1 kg of pretreatment liquor, completely ion-free water was stirred with component (c) until everything had gone into solution. This was followed by addition of components (b) and (d), and homogenization, with stirring. Then resin (a) according to table 1 was added. Pretreatment liquors as per table 2 were produced.

Key to abbreviations: b.1 : associative thickener, reaction product of hexamethylene diisocyanate (HDI) with ethoxylated n-CisH37OH of M _w 10,000 g/mol, the ethoxylated fatty alcohol being used in an excess of 50 mol%, based on isocyanate groups; c.1 : polyethyleneimine, M _w 25,000 g/mol c.2: diallyldimethylammonium chloride homopolymer; M _w 10,000 g/mol d.1 : tri-n-butyl phosphate defoamer d.2: 20% by weight of solution of 1 ,2-benzisothiazolin-3-one in propylene glycol d.3: dispersing binder according to Example IV.

Table 2: Inventive pretreatment liquors

11.2. Production of inks for ink jet process

The hereinbelow recited inks for the ink jet process were produced by mixing the constituents identified in table 4. Initially, mix components M1 to M3 were produced by introducing each of the constituents recited in table 3 into a ball mill, making up to 100 ml with distilled water in each case and dispersing. A glass beaker was then used as a location to formulate ink T1 from mix component M1 and the ingredients of table 5, ink T2 from mix component M2 and the ingredients of table 4 and ink T3 from mix component M3 and the ingredients of table 5, making up to 100 ml with distilled water each time.

Wetting agent 1 : [(CHs) ₃ Si] ₂ Si(CH ₃ )[CH ₂ ]S-O-(CH ₂ CH ₂ O) ₃ H

Biocide 1 : 20% by weight of solution of 1 ,2-benzisothiazolin-3-one in dipropylene glycol

Table 3: Composition of mix components M1 to M 3

All use levels reported in g/100 ml. 100 ml of mix component M1 , M2 and M3 were produced in each case.

All use levels reported in g/100 ml. 100 ml of ink T1 , T2 and T3 were produced in each case.

11.3 Preparation of acrylate binder C-1

A mixture 11.3.1 was prepared by dispersing 7.8 g of freshly distilled acrylic acid, 58.2 g of styrene, 252 g of n-butyl acrylate 282 g of ethyl acrylate

35,7 g of a 28 % by weight aqueous solution of n-Ci ₂ H ₂₅ (OCH ₂ CH ₂ )3OSO ₃ Na 21 g of a 20% by weight aqueous solution of compound X

,23

R" — [N(CH ₂ CH ₂ 2O^)/ ₆ 6H' ']J2 X

with R ²³ being cis-(CH ₂ ) ₈ -CH=CH-(CH ₂ ) ₇ CH ₃ ,

in 400 ml of distilled water.

Mixture 11.3.2 was prepared by dissolving 2.4 g Of Na ₂ S ₂ Os in 100 ml of distilled water. Mixture 11.3.3 was prepared by dissolving 1.2 g of HO-CH ₂ SO ₂ Na in 100 ml of distilled water.

A 5-leter-vessel was charged with 300 g of distilled water and 13.6 g of a 33 % by weight seed of polystyrene (average diameter 30 nm, in water). A suspension was formed. Nitrogen was bubbled through the suspension over a period of 15 minutes. Then, the suspension was heated to 75°C. The addition of mixtures 11.3.1 , II.3.2 and II.3.3 was started simultaneously. The addition of mixture 11.3.1 was completed within 3 hours, the addition of mixtures II.3.2 and II.3.3 was completed within 3 hours and 15

minutes. During addition of said mixtures and during 30 minutes after having finished addition of mixture 11.3.2, stirring at 75°C was continued for additional 30 minutes. Then, 3 g of a 25% by weight aqueous solution of ammonia was added. Then, a solution of 2 g of tert-butyl hydroperoxide in 22.5 ml of distilled water and a solution of 1.7 g of HO-CH2Sθ2lMa in 25 ml of distilled water were added simultaneously over a period of 90 minutes. Finally, the mixture was cooled down to room temperature. Aqueous ammonia was added to raise the pH value to 7 to 7.5 (about 2 g of 25% by weight aqueous solution). The dispersion obtained was filtered using a net with 125 μm mesh. By this step, about 2 g of coagulated material were removed.

Acrylate binder C-1 was obtained.

Solids contents: 38.7% by weight, pH value: 7, dynamic viscosity: 30 mPa-s (23°C). Average particle diameter: maximum at 146 nm. Glass transition temperature: -22°C (DSC).

11.4 Polyurethane binder C-2

Comparative example D3 of EP 1 001 002 B1 , but diluted with water up to a solids con- tent of 30% by weight.

III. Inventive coloration of non-wovens from polypropylene

As substrate from polypropylene, a nonwoven from polypropylene with 50 g/m ² was used.

111.1. General prescription for step (A)

Nonwoven from polypropylene PP- 1 was treated with a pretreatment liquor as per ta- ble 2 on a pad-mangle from Mathis (model No. HVF63003). The nip pressure of the rolls was 2.2 bar, resulting in a wet pickup of 60%. The application speed was 1 m/min. The pretreated fabric was subsequently dried at 90 ⁰ C.

Nonwovens from polypropylene pretreated according to the present invention were obtained.

III.2 Printing with inks and aftertreatment

Pretreated polypropylene nonwovens were each printed with an ink on a Mi- maki TX 1600 S printer.

After drying at room temperature, printed nonwovens were aftertreated on a foulard with either an aqueous liquor, containing

120 g/l acrylate binder C-1 (tell qu'elle), 5 g/l fixing agent FA-1 , 1 g/l (NH ₄ )H ₂ PO ₄

or

30 g/l polyurethane binder C-2 (tell qu'elle), 6 g/l fixing agent FA-2,

pick-up was set to 175% by weight, then fixing was performed at 120 ⁰ C for 2 minutes.

Rubfastness:

Color strength:

Pretreated and printed fabrics according to the present invention possessed excellent hand and brilliant colors. The wash fastness and water fastness of inventively colored PP.1 and PP.2 was excellent as well:

Wash fastness test ISO 105-C06-A2S, 4O ⁰ C

Water fastness test ISO 105-E01

Said results refer to each PP.1 and PP.2.