U.S. patent application number 10/529078 was filed with the patent office on 2006-01-19 for pre-treatment liquor for preparing textile substrates for inkjet printing.
This patent application is currently assigned to BASF Aktiengesellschaft. Invention is credited to Mike Freche, Dieter Freyberg, Ulrike Hees, Heinz Heissler, Michael Kluge, Friedrich-Wilhelm Raulfs, Karl Siemensmeyer.
Application Number | 20060010619 10/529078 |
Document ID | / |
Family ID | 31969627 |
Filed Date | 2006-01-19 |
United States Patent
Application |
20060010619 |
Kind Code |
A1 |
Hees; Ulrike ; et
al. |
January 19, 2006 |
Pre-treatment liquor for preparing textile substrates for inkjet
printing
Abstract
Aqueous pretreatment liquor for preparing a textile substrate
for inkjet printing, comprising (A) one or more polycationic
compounds, (B) one or more thickeners, (C) optionally customary
additives, (C) water. Preferred polycationic compounds (A) are
polymers or copolymers of diallyldialkylammonium monomers.
Preferred thickeners are obtainable from (i) polyetherdiols, (ii)
diisocyanates and (iii) compounds, R of the general formula R--OH,
R--SH, R--NH.sub.2, RR NH or R--COOH, where R is a hydrophobic
aliphatic or aromatic radical of at least 4 carbon atoms and R--OH
may have been alkoxylated, and also further derivatives thereof
that are capable of forming a urethane, thiourethane or urea bond,
or from (i) polyetherdiols with (iv) compounds of the general
formula R--OH or R--COOH, where R is a hydrophobic aliphatic or
aromatic radical of at least 4 carbon atoms and R--OH may have been
alkoxylated, and also further derivatives thereof that are capable
of forming an ether or ester bond, and or from compounds (ii) and
(iii).
Inventors: |
Hees; Ulrike; (Mannheim,
DE) ; Kluge; Michael; (Ludwigshafen, DE) ;
Freche; Mike; (Kerzenheim, DE) ; Freyberg;
Dieter; (Einselthum, DE) ; Siemensmeyer; Karl;
(Frankenthal, DE) ; Heissler; Heinz; (Frankenthal,
DE) ; Raulfs; Friedrich-Wilhelm; (Mannheim,
DE) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
BASF Aktiengesellschaft
Ludwigshafen
DE
67056
|
Family ID: |
31969627 |
Appl. No.: |
10/529078 |
Filed: |
September 24, 2003 |
PCT Filed: |
September 24, 2003 |
PCT NO: |
PCT/EP03/10632 |
371 Date: |
March 24, 2005 |
Current U.S.
Class: |
8/445 |
Current CPC
Class: |
D06P 1/607 20130101;
D06M 15/3562 20130101; D06P 1/649 20130101; D06P 5/30 20130101;
D06P 1/613 20130101; D06P 1/5242 20130101 |
Class at
Publication: |
008/445 |
International
Class: |
D06P 5/00 20060101
D06P005/00 |
Claims
1-10. (canceled)
11. An aqueous pretreatment liquor for preparing a textile
substrate for inkjet printing, comprising: (A) one or more
polycationic compounds, (B) one or more associative thickeners of
the general formula (I), (II) and/or (III)
U-[-T-(M).sub.y-].sub.x-U (I) U-(M).sub.y-U (II) U-T-U (III) where:
(M).sub.y is a unit derived from polyalkylene ether, M being an
individual alkylene ether unit and y being from 1 to 100,000, T is
in each occurrence the same or different unit derived from a
diisocyanate, x is on average from 1 to 500, U is in each
occurrence the same or different unit of at least 4 carbon atoms
that is derived from aliphatic or aromatic alcohols, alkoxylated
alcohols, thiols, amines or carboxylic acids, (C) optionally
customary additives, (D) water.
12. An aqueous pretreatment liquor as claimed in claim 11, wherein
said polycationic compounds (A) are polymers or copolymers of
diallyldialkylammonium monomers.
13. An aqueous pretreatment liquor as claimed in claim 12, wherein
said polycationic compounds (A) are a diallyldimethylammonium
chloride homopolymer.
14. An aqueous pretreatment liquor as claimed in claim 13, wherein
said compounds of the general formula (I) are obtained from (i)
polyetherdiols, (ii) diisocyanates, and (iii) compounds, R of the
general formula R--OH, R--SH, R--NH.sub.2, RR'NH or R--COOH, where
R is a hydrophobic aliphatic or aromatic radical of at least 4
carbon atoms and R--OH may have been alkoxylated, and also further
derivatives thereof that are capable of forming a urethane,
thiourethane or urea bond, said compounds of the formula (II) are
obtained from (i) polyetherdiols with (iv) compounds of the general
formula R--OH or R--COOH, where R is a hydrophobic aliphatic or
aromatic radical of at least 4 carbon atoms and R--OH may have been
alkoxylated, and also further derivatives thereof that are capable
of forming an ether or ester bond, and said compounds of the
formula (III) are obtained from said compounds (ii) and (iii).
15. An aqueous pretreatment liquor as claimed in claim 13, wherein
said polyetherdiols (ii) are at least one selected from the group
consisting of polyethylene glycol, polypropylene glycol and
polytetrahydrofuran and copolymers of ethylene oxide and propylene
oxide or butylene oxide and terpolymers of ethylene oxide and
propylene oxide and butylene oxide.
16. An aqueous pretreatment liquor as claimed in claim 11,
comprising: (a) from 0.1% to 50% by weight of polycationic
compounds (A), (b) from 0.1% to 50% by weight of thickeners (B),
(c) from 0% to 30% by weight of customary additives (C), and (d)
water ad 100% by weight.
17. A pretreatment composition comprising said components (A), (B)
and optionally (C) as defined in claim 11.
18. A process for pretreating a textile substrate for inkjet
printing, which comprises applying the aqueous pretreatment liquor
of claim 11 to said textile substrate and subsequently drying the
impregnated textile substrate.
19. A process for printing a textile substrate by the inkjet
process, which comprises applying the aqueous pretreatment liquor
of claim 11, drying the impregnated textile substrate and printing
said impregnated textile substrate by the inkjet process.
20. The printed textile substrate obtained by the process of claim
19.
Description
[0001] The present invention relates to aqueous pretreatment
liquors for preparing textile substrates for inkjet printing.
[0002] It is known to treat textile materials which are to be
printed by the inkjet printing process with a pretreatment liquor
to improve the performance properties of the printed textiles. This
pretreatment is intended to improve the holdout of the inks on the
textile substrate, and to provide a higher color strength and also
better fixation of the inks on the substrate. It would be desirable
to have distinctly crisper contours (improved definition) for the
prints on the substrate in order that higher resolutions (higher
dpi) may be achieved for the prints.
[0003] Prints with pigment inks can in principle be carried out on
all textile fabrics. Numerous patent applications describe the use
of cationic substances or thickeners to improve the ink holdout
when inkjet printing with reactive dyes on cotton or other
cellulosic fibers.
[0004] EP-A 0 928 841 describes the use of natural thickeners and
of divalent metal salts when printing direct dyes and pigments onto
silk. Polyquaternary or polycationic compounds are not mentioned,
nor are disperse dyes.
[0005] WO 99/33669 discloses the preprint treatment of a textile
with cationic compounds to improve the holdout of disperse dye
inks. Only low molecular weight cationic compounds are mentioned,
no polyquaternary or polycationic compounds.
[0006] U.S. Pat. No. 6,001,137 describes the use of polycationic
compounds based on epichlorohydrin copolymers for improving
fixation. Improved ink holdout is not mentioned.
[0007] WO 00/03081 describes a pretreatment of textiles with
textile binders and melamine crosslinkers for inkjet printing with
pigments. The pretreatment results in good fastnesses for the
prints. There is no mention of an improved printed image due to
superior ink holdout and the use of cationic compounds.
[0008] JP 62231787 describes the use of divalent inorganic metal
salts and/or cationic compounds and crosslinkers for preparing
textiles for inkjet printing with pigments. The crosslinker leads
to crosslinking with a binder included in the ink. The use of
polycationic compounds is not mentioned, nor is the use of
polyethylene glycol derivatives or other thickeners.
[0009] WO 00/56972 describes the use of cationic polymers and
copolymers and also of polymer latices as binders for the
pretreatment of textile substrates for inkjet printing.
[0010] The disadvantage with prior art processes is a frequently
inadequate definition of the printed image on the textile
substrate. This is due to the spreading of the inks on the
substrate.
[0011] It is an object of the present invention to provide a
pretreatment liquor for preparing textile substrates for inkjet
printing which produces improved ink holdout on the printed textile
substrates. It is a particular object of the present invention to
improve the ink holdout of cellulosic textile substrates printed
with pigment inks and of textile polyester fiber substrates printed
with disperse dye inks. It is a further object of the present
invention to improve the fixation for printing with disperse dye
inks and so achieve an enhanced brilliance and color strength for
the prints.
[0012] We have found that these objects are achieved by an aqueous
pretreatment liquor for preparing a textile substrate for inkjet
printing, comprising [0013] (A) one or more polycationic compounds,
[0014] (B) one or more thickeners, [0015] (C) optionally customary
additives, [0016] (D) water.
[0017] Component (A) in the aqueous pretreatment liquors according
to the present invention is one or more polycationic compounds.
[0018] Useful polycationic compounds include for example cationic
homopolymers or copolymers 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 polyallylamine hydrochloride, allylamine
hydrochloride-diallylamine hydrochloride copolymer,
N-vinylacryloylamidine hydrochloride-acrylamide copolymer,
dialkylamine-epichlorohydrin polymer,
polyamide-polyamine-epichlorohydrin polymer,
dicyandiamide-formaldehyde polycondensate,
polyethylenepolyamine-dicyandiamide polycondensate,
polyethyleneimine hydrochloride,
poly(meth)acryloyloxyalkyldialkylamine hydrochloride,
(meth)acryloyloxyalkyldialkylamine hydrochloride-acrylamide
copolymer and poly(meth)acryloyloxyalkyltrialkylammonium
chloride.
[0019] Preferred polycationic compounds (A) are homo- or copolymers
of diallyldialkylammonium monomers, such as
polydiallyldimethylammonium chloride (polyDADMAC),
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 homopolymer (polyDADMAC).
[0020] Copolymers of the monomers mentioned may also contain
nonionic monomers, for example vinylpyrrolidone, (partially
saponified) vinyl acetate or hydroxy(meth)acrylate, as
comonomers.
[0021] Processes for preparing diallyldialkylammonium homo- or
copolymers are described for example in U.S. Pat. No. 4,742,134,
U.S. Pat. No. 5,283,306 and EP-A 0 264 710.
[0022] In one embodiment of the present invention, the aqueous
pretreatment liquors comprise polymers or copolymers of
diallyldialkylammonium monomers, preferably polymers or copolymers
of diallyldimethylammonium chloride and more preferably
diallyldimethylammonium chloride homopolymer, as polycationic
compounds (A), and one or more thickeners (B).
[0023] Component (B) in the aqueous pretreatment liquors according
to the present invention is one or more thickeners.
[0024] Useful thickeners (B) include natural thickeners such as
alginates, polysaccharides, starch, carboxymethylcellulose, guar
gum powder and also derivatives thereof, and synthetic thickeners
such as optionally acrylic acid homo- and copolymers.
[0025] Preferred thickeners (B) are associative thickeners of the
general formula (I), (II) and/or (III) U-[-T-(M).sub.y-].sub.x-U
(I) U-(M).sub.y-U (II) U-T-U (III) where: [0026] (M).sub.y is a
unit derived from polyalkylene ether, M being an individual
alkylene ether unit and y being from 1 to 100 000, and preferably
from 10 to 10 000, [0027] T is in each occurrence the same or
different unit derived from a diisocyanate, [0028] x is on average
from 1 to 500, preferably from 1 to 2 and more preferably about 1.
[0029] U is in each occurrence the same or different unit of at
least 4 carbon atoms and preferably at least 6 carbon atoms, that
is derived from aliphatic or aromatic alcohols, alkoxylated
alcohols, thiols, amines or carboxylic acids.
[0030] In one embodiment of the present invention, the aqueous
pretreatment liquors comprise one or more polycationic compounds
(A) and one or more associative thickeners of the general formula
(I) and/or (II).
[0031] Associative thickeners of the general formula (I) are
obtainable by reaction of [0032] (i) polyetherdiols, [0033] (ii)
diisocyanates and [0034] (iii) compounds, R of the general formula
R--OH, R--SH, R--NH.sub.2, RR'NH or R--COOH, where R is a
hydrophobic aliphatic or aromatic radical of at least 4 carbon
atoms and R--OH may have been alkoxylated, and also further
derivatives thereof that are capable of forming a urethane,
thiourethane or urea bond.
[0035] Polyetherdiols (i) for the purposes of the present
inventions are polyethylene glycol, polypropylene glycol and
polytetrahydrofuran, but also copolymers of ethylene oxide and
propylene oxide or butylene oxide or terpolymers of ethylene oxide,
propylene oxide and butylene oxide, and the copolymers can be
present as block copolymers or random copolymers or
terpolymers.
[0036] Useful diisocyanates (ii) include diisocyanates having NCO
groups of the same or a different reactivity. Examples of
diisocyanates having NCO groups of the same reactivity are aromatic
or aliphatic diisocyanates, preference being given to aliphatic
diisocyanates such as tetramethylene diisocyanate, hexamethylene
diisocyanate (HDI), octamethylene diisocyanate, decamethylene
diisocyanate, dodecamethylene diisocyanate, tetradecamethylene
diisocyanate, trimethylhexane diisocyanate, tetramethylhexane
diisocyanate, 1,4-, 1,3- or 1,2-diisocyanatocyclohexane,
4,4'-diisocyanatocyclo-hexylmethane,
1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane
(isophorone diisocyanate) and 2,4- and
2,6-diisocyanato-1-methylcyclohexane, of which hexamethylene
diisocyanate and isophorone diisocyanate are particularly
preferably preferred. A further particularly preferred diisocyanate
is m-tetramethylxylene diisocyanate (TMXDI).
[0037] 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).
[0038] 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.
[0039] It is naturally also possible to use mixtures of two or more
of the aforementioned isocyanates.
[0040] 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 polyisocyanate. Examples of useful
polyisocyanates are biurets and allophanates of HDI or TDI.
[0041] Very particularly preferred diisocyanates are HDI, IPDI, MDI
and TDI.
[0042] The 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.
[0043] The reaction of the diisocyanates with the polyetherdiols is
typically carried out in the presence of a catalyst.
[0044] The catalysts are preferably used in an amount from 0.01% to
10% by weight and preferably from 0.05% to 5% by weight. The
reaction can be carried out in a solvent, in which case useful
solvents include in principle all solvents which react neither with
the polyurethane nor with the polyether derivative.
[0045] Useful catalysts to speed especially the reaction between
the NCO groups of the diisocyanates and the hydroxyl groups of the
polyetherdiols are the well-known tertiary amines, for example
triethylamine, dimethylcyclohexylamine, N-methylmorpholine,
N,N'-dimethylpiperazine, 2-dimethylaminoethoxyethanol,
diazabicyclo(2.2.2)octane and the like and also in particular
organic metal compounds such as titanate esters, iron compounds
such as for example iron(III) acetylacetonate, tin compounds, for
example tin diacetate, tin dioctanoate, tin dilaurate or the
dialkyl derivatives of tin dialkyl salts of aliphatic carboxylic
acids such as dibutyltin diacetate, dibutyltin dilaurate or the
like.
[0046] The synthesis of the associative thickeners is generally
carried out without a solvent or in an aprotic solvent, for example
in 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.degree. C. to the boiling point of the
solvent used. The reaction is generally carried out under
atmospheric pressure, but it may also be carried out in autoclaves
at up to 20 bar.
[0047] Reacting the NCO-terminated products with aliphatic or
aromatic alcohols, thiols, primary or secondary amines or
carboxylic acids (ii) converts the reaction products of the
components (i) and (ii), which contain free isocyanate groups, into
hydrophobicized products.
[0048] Suitable are in particular alcohols and primary or secondary
amines having [0049] C.sub.8-C.sub.40-alkyl radicals such as
n-octyl, n-nonyl, n-decyl, n-dodecyl, n-hexadecyl or n-eicosyl;
[0050] C.sub.6-C.sub.14-aryl radicals such as phenyl,
.alpha.-naphthyl, .beta.-naphthyl, 1-anthracenyl, 2-anthracenyl or
9-anthracenyl or heteroaromatic radicals such as .alpha.-pyridyl,
.beta.-pyridyl, .gamma.-pyridyl, N-pyrryl, .beta.-pyrryl,
.gamma.-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 or
.alpha.-phenanthrolinyl; [0051] C.sub.7-C.sub.13-aralkyl and
preferably C.sub.7- to C.sub.12-phenylalkyl such as benzyl,
1-phenethyl, 2-phenethyl, 1-phenyl-propyl, 2-phenyl-propyl,
3-phenyl-propyl, neophyl (1-methyl-1-phenylethyl), 1-phenyl-butyl,
2-phenyl-butyl, 3-phenyl-butyl and 4-phenyl-butyl, more preferably
benzyl.
[0052] The alcohols R--OH can also have been alkoxylated with
ethylene oxide, propylene oxide or butylene oxide, in which case
not only homo- but also block copolymers of the alkyene oxides
mentioned can be used, typically having about 20-500 alkylene oxide
units. The alcohols R--OH can also have been alkoxylated with
THF.
[0053] In general, the compound (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%,
based on free NCO groups.
[0054] The hydrophobic group R can also be attached to the
polyetherdiol (ii) via an ester or ether bridge. Associative
thickeners of the general formula (II) are thus obtainable by
reaction of [0055] (i) polyetherdiols with [0056] (iv) compounds of
the general formula R--OH or R--COOH, where R is a hydrophobic
aliphatic or aromatic radical of at least 4 carbon atoms and has
the above-mentioned meanings, wherein R--OH may have been
alkoxylated (as described above), and also further derivatives
thereof that are capable of forming an ether or ester bond.
[0057] Compounds of the formula (III) are finally obtained from the
diisocyanates (ii) and the compounds (iii) without polyetherdiols
(i) being present. The compounds (iii) can be used in
stoichiometric excess.
[0058] In a particularly preferred embodiment, the aqueous
pretreatment liquors according to the present invention comprise
polymers or copolymers of diallyldialkylammonium monomers and
especially diallyldimethylammonium chloride homopolymer as
polycationic compounds (A) and one or more associative thickeners
of the formula (I) and/or (II) as thickeners (B).
[0059] As well as the components (A) and (B), the aqueous treatment
liquors according to the present invention may comprise customary
additives as a component (C). Examples of customary additives are
defoamers, emulsifiers, solvents, biocides, deaerators and wetting
agents.
[0060] The aqueous treatment liquors according to the present
invention typically comprise [0061] (a) from 0.1% to 50% by weight
and preferably from about 0.5% to 30% by weight of the polycationic
compounds (A), [0062] (b) from 0.1% to 50% by weight and preferably
from 0.5% to 30% by weight of the thickeners (B), [0063] (c) from
0% to 30% by weight and preferably from 0.5% to 20% by weight of
customary additives (C), and [0064] (d) water ad 100% by
weight.
[0065] What is surprising is particularly that the pretreatment
liquors according to the present invention provide--in one and the
same liquor--distinct improvements both in the properties of cotton
fabrics and those of polyester fabrics for printing with pigment
inks and with disperse dye inks, respectively. Cotton or cotton
blend fabrics are typically printed with pigment inks and polyester
fabrics typically with disperse dye inks. In addition, the
pretreatment has a favorable effect on fixation when printing with
disperse dye inks, permitting more brilliant as well as darker
(especially black) colors.
[0066] It is a further surprise that the hand of the substrates
pretreated according to the present invention is not adversely
affected.
[0067] The present invention further provides a treatment
composition comprising the components (A), (B) or optionally (C)
whence the aqueous treatment liquors according to the present
invention are obtainable by diluting with water.
[0068] A further aspect of the present invention is a process for
printing sheetlike textile substrates by the inkjet process,
characterized by the textile substrates to be printed being
pretreated with the aqueous pretreatment liquors.
[0069] The present invention further provides the printed textile
substrates themselves.
[0070] The present invention yet further provides a process for
pretreating textile substrates with the aqueous pretreatment
liquors according to the present invention.
[0071] The pretreatment operation for inkjet printing comprises
applying the pretreatment liquor and subsequently drying the
impregnated textile substrate.
[0072] The pretreatment liquor can be applied by an exhaust process
or by a continuous process involving a forced application.
[0073] Exhaust processes are suitable whenever the pretreatment
agent possesses distinct affinity for the substrate. This will be
particularly the case when the pretreatment agent and the substrate
possess different ionogenicities, for example in that the
pretreatment agent is cationic in nature and the substrate fiber
anionic. There are various forms of the exhaust process which are
known in principle from the field of dyeing. For example, the
textile can be in a wound-up state. The treatment liquor is then
forced under pressure through the wound-up textile, and the
direction of flow of the treatment liquor can be from in to out or
else, in fully flooded machines, from out to in. To ensure a
uniform application, a change in the direction of flow of the
treatment liquor is advantageous. In another embodiment, the fabric
is in an unconstrained state in the pretreatment liquor and moves
with the pretreatment liquor. In a further embodiment, the textile
can also be pulled through a standing bath. In this case, the
textile is preferably repeatedly pulled through the treatment bath.
The direction of movement of the textile should reverse, since this
is conducive of a uniform application. More particular details
concerning these application processes can be found in the relevant
literature, for example Veredlung von Textilien, VEB Fachbuchverlag
Leipzig, 1st edition 1976, page 93 ff.
[0074] Useful continuous processes for application include all
processes in which the pretreatment composition according to the
present invention can be applied uniformly or imagewise. Of
particular suitability here are all printing processes and also all
processes in which the textile is uniformly saturated with the
pretreatment composition. The fundamental difference from the
exhaust processes is that a forced application is realized. The
pretreatment liquor need not have any affinity for fiber for these
processes.
[0075] Useful printing processes include for example all screen
printing processes. Screen printing is an important process which
is utilized inter alia in the production of printed fabrics. In
screen printing, the print pastes are forced by a squeegee through
a fine mesh and onto the substrate to be printed. The mesh can be
formed from synthetic fibers, as in flat screen printing machines,
or metals, as in rotary screen printing machines.
[0076] But relief printing, gravure printing or roller printing,
being common textile printing processes, are also suitable for
applying the pretreatment liquor. More particular details
concerning the individual printing processes can be found on pages
110 ff of the literature reference cited above.
[0077] As well as printing processes, however, it is also possible
to use any technique wherein the textile is uniformly saturated
with the pretreatment liquor. This is accomplished for example in
the form that the textile is led through a trough filled with the
pretreatment composition and subsequently squeezed off by two
rollers to a defined wet pickup. But the application can also be
accomplished in the form that the textile is led through a nip
formed between two rotating rollers and filled with the
pretreatment liquor. The rollers will simultaneously squeeze off
the textile material to the desired wet pickup. There are in
addition many other possible configurations for this pad-mangle
technology, which are all likewise suitable for applying the
pretreatment liquor.
[0078] In addition, defined amounts of the pretreatment liquor can
be applied by generally known spraying and pouring techniques.
[0079] After the pretreatment composition has been applied, the
textile is dried. This may be accomplished by heating the
impregnated textile sufficiently for the water present to be able
to evaporate off. It is preferable to employ temperatures of 80 and
120.degree. 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 textile
is kept under tension in this operation in order that the formation
of creases may be avoided.
[0080] Examples of textile substrates to be printed which are
pretreated according to the present invention are fibers, yarns,
threads, knits, wovens, nonwovens and garments composed of
polyester, modified polyester, polyester blend fabric, cellulosic
materials such as cotton, cotton blend fabrics, jute, flax, hemp
and ramie, viscose, wool, silk, polyamide, polyamide blend fabrics,
polyacrylonitrile, triacetate, acetate, polycarbonate,
polypropylene, polyvinyl chloride, polyester microfibers and glass
fiber fabrics.
[0081] The inkjet process typically utilizes aqueous inks, which
are sprayed as small droplets directly onto the substrate. There is
a continuous form of the process, in which the ink is pressed at
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 inkjet or drop-on-demand
process, in which the ink is exposed 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 an ink
droplet. 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.
[0082] The inkjet inks used for printing textile substrates in the
process according to the present invention, as well as dispersants,
typically contain water or a water-solvent mixture and also finely
divided organic or inorganic colorants which are preferably
substantially insoluble in water or in the water-solvent mixture,
these colorants being, for example by the definition in German
standard specification DIN 55944, pigments. Disperse dyes can be
used instead of pigments. But the inks can also contain direct,
acid, reactive and vat dyes as dissolved dyes. The soluble dyes
mentioned can be present as brightening agents in pigment
preparations, in which case the soluble dyes used, especially
direct, acid or reactive dyes, are similar in hue to the
pigment.
[0083] The example which follows illustrates the invention.
EXAMPLE
A Making a Pretreatment Liquor
[0084] Component A: associative thickener, reaction product of HDI
with ethoxylated fatty alcohol having a molecular weight of about
10 000 g/mol, the ethoxylated fatty alcohol having been used in an
excess of 50%, based on isocyanate groups; [0085] component B:
diallyldimethylammonium chloride homopolymer as a polycationic
compound; [0086] for 1 kg of liquor 889.8 g of demineralized water
are stirred with 10 g of component A until everything has
dissolved. This is followed by stirred addition of 100 g of
component B and 0.2 g of a commercially available defoamer
(Entschaumer TC from BASF AG) and homogenization. B Pretreatment of
a Textile Fabric
[0087] The following fabrics were pretreated by padding with the
pretreatment liquor: [0088] (1) cotton 283 [0089] (2) polyester
flagging [0090] (3) 50/50 cotton/polyester blend fabric
[0091] The liquor is filled into the padder. The fabric is led
through the liquor in the padder and then squeezed off between 2
rolls.
[0092] The fabric is then dried at 80.degree. C.
C Printing the Pretreated Fabric with a Pattern
[0093] a) The cotton fabric (1) and the cotton/polyester blend
fabric (3) are printed with a pigment ink (Helizarin.RTM. ink) on a
Mimaki TX 1600 S printer. [0094] b) The polyester fabric (2) is
printed with a disperse dye ink (Bafixan.RTM. ink) on an Epson 3000
printer.
[0095] The ink add-on is the range from 100% to 400%.
[0096] The printed polyester fabric (2) is subsequently fixed with
hot air for about 90 s.
D Reduction Clearing the Prints
[0097] The prints are subsequently reduction cleared by [0098] (i)
rinsing in cold water, followed by hot water, [0099] (ii)
subsequent treatment at 80.degree. C. in a mixture of 2 g/L of
concentrated hydrosulfite solution, 2 mL of 50% by weight aqueous
sodium hydroxide solution, 1 mL/L of Kieralon DB and 2 mL/L of
Trilon TA for 10-12 min, [0100] (iii) followed by a cold rinse for
2-3 min, [0101] (iv) neutralization in a solution of 1 mL/L of
glacial acetic acid, [0102] (v) a further cold rinse. E
Quantitative Examinations by Colorimetery
[0103] Quantitative examinations were carried out by means of
colorimetry. The measurements were carried out using an X-Rite CA22
spectrophotometer and analyzed using X-Rite Color Master
software.
[0104] The respectively untreated fabric was used as a standard for
the colorimetric measurements. A higher value for color strength
and for chroma (as per M. Richter, Einfuhrung in die Farbmetrik,
DeGruyter, Berlin 1981) for the textile pretreated according to the
present invention thus is evidence of an improved print result.
[0105] I. Helizarin.RTM. on cotton 283, fabric weight=119.7
g/m.sup.2, cotton poplin, staple length 25-30 mm, Tegewa degree of
desizing 9, average degree of polymerization>1800; standard:
untreated fabric. The results are summarized in table 1.
TABLE-US-00001 TABLE 1 Color strength Color strength Color
untreated pretreated .DELTA. chroma cyan 100 150.84 5.71 magenta
100 124.97 1.55 yellow 100 132.89 4.49 black 100 220.2 -0.15
[0106] II. Helizarin.RTM. on cotton/polyester blend fabric (50%
cotton), fabric weight=114.7 g/m.sup.2. The results are summarized
in table 2. TABLE-US-00002 TABLE 2 Color strength Color strength
Color untreated pretreated .DELTA. chroma cyan 100 197.38 4.81
magenta 100 119.64 1.10 yellow 100 147.48 6.58 black 100 219.14
0.92
[0107] III. Bafixan.RTM. on polyester flagging, fabric weight=104.7
g/m.sup.2. The results are summarized in table 3. TABLE-US-00003
TABLE 3 Color strength Color strength Color untreated pretreated
.DELTA. chroma cyan 100 212.51 0.60 magenta 100 130.65 1.01 yellow
100 187.92 9.16 black 100 115.40 -0.92
Qualitative Comparison:
[0108] The pretreatment of the fabric has improved ink holdout,
giving better resolution. Fabric hand is not impaired by the
pretreatment.
* * * * *