EP3473768A1

EP3473768A1 - Composition for the treatment of fibrous materials for the printing thereof

Info

Publication number: EP3473768A1
Application number: EP18201862.2A
Authority: EP
Inventors: Vincenzino FRANCHINI
Original assignee: Efeson - Chemical Research & Engineering Development
Current assignee: RelCo Relazioni Commerciali Srl; Tilab Srl; TINTORIA EMILIANA Srl
Priority date: 2017-10-23
Filing date: 2018-10-22
Publication date: 2019-04-24
Anticipated expiration: 2038-10-22
Also published as: EP3473768B1; EP3473767A1

Abstract

The composition for printing fibrous materials comprises at least one hydrotropic substance, excluding urea or a derivative thereof, and a hygroscopic substance. The composition can be used in the printing of fibrous materials through both silk screen printing, such as rotary or flat screen printing, and inkjet digital printing, with all the classes of reactive and acid dyes.

Description

Technical field of the invention

The present invention concerns a composition for the treatment of fibrous materials, in particular for the printing thereof.
More precisely, the invention concerns a composition for the preparation of preprint textile substrates in processes relative to rotary or flat screen printing and inkjet printing.

Known art

It is known that in the preparation of paste for printing textile through both silk screen printing, such as rotary or flat screen printing, and inkjet digital printing, it is essential to use urea and, more rarely, some derivatives thereof.
It is known that urea results in a very high pollutant load in the waste water due to its low biodegradability. Said low biodegradability is due to the hydrolysis reaction of the urea which occurs in a first step with the formation of ammonium cyanate; in a second step, the ammonium cyanate decomposes into ammonia and carbonic acid. Said reaction is far to the left, namely towards the first step, and this results in having persistent quantities of urea and ammonium cyanate with consequent high nitrogen load and presence of quaternary ammonium which is toxic for aquatic organisms. ECHA datum for biodegradability rate of urea: 15.5% after 28 days.
In practice, in the field of textile printing, after printing the waste water carries a very high nitrogen load to the purification plants, in particular beyond the limitations set forth by the European Community.
The need is therefore felt to propose alternative compositions completely replacing the urea and its derivatives.
It is also known that the alternatives proposed so far have entailed an unacceptable lowering of the colour rendering in addition to a tonal shift differentiated according to the dye and the relative concentration.
An in-depth non-obvious study has been necessary to find highly biodegradable non-toxic substituents that fully substitute the various intrinsic properties of urea in relation to the complex chemical/physical system that governs the printing process together with some points which are still scientifically obscure concerning the mechanisms of interaction. It is clear that the set of these different properties of urea are at the basis of the quality results guaranteed by urea and not achieved with the current alternatives, but said intrinsic properties of urea also make it difficult to substitute.

Brief summary of the invention

The object of the present invention is therefore to propose a composition that solves the above-mentioned problem and provides an alternative to urea and to its intrinsic properties for printing textile through both silk screen printing processes, such as rotary or flat screen printing, and inkjet digital printing, which has the following characteristics:

maintenance of quality standards
significant reduction in environmental impact
high eco-toxicological profile
saving in energy and water resources

A further object of the invention is to provide a composition that can be used in textile print through both silk screen printing, such as rotary or flat screen printing, and inkjet digital printing, with all classes of reactive dyes and with all classes of acid dyes (which are the most commonly used on the market), and with other categories of dyes requiring the use of urea.
These and other objects are achieved by a composition for the treatment of fibrous materials for the printing thereof, both rotary or flat screen printing and inkjet digital printing, according to claim 1.
The dependent claims define possible and advantageous embodiments of the invention.

Description of embodiments of the invention

According to the invention, the composition for use in textile print through both silk screen printing, such as rotary or flat screen printing, and inkjet digital printing, comprises at least one hydrotropic substance which is not urea or a derivative thereof and at least one hygroscopic substance. This provides a composition with low environmental impact, since by eliminating the use of urea, the behaviour resulting from hydrolysis of the urea is avoided, namely persistence in the waste water of undissociated urea and ammonium cyanate, relative quaternized ammonium and high nitrogen load.
It has in fact been discovered that urea allows good print results to be obtained, as it has not only hydrotropic properties but also hygroscopic properties, and has a third function which is that of forming a eutectic mixture with water, thus lowering the melting point thereof below the vaporization temperature, being dissolved and then becoming a solvent of the reaction.
For substituting the urea and maintaining high print quality standards, hydrotropic and hygroscopic substances must be provided. In the composition according to the present invention, designed to treat fibrous substrates for the printing thereof, the hygroscopic substance serves as a cosolvent that solubilizes the dye in the fibre, thus compensating for the low presence of water, whereas the hydrotropic substance has the function of promoting the spreading of the dye from the solvent towards the inside of the fibre. In order to completely simulate the behaviour of the urea, a hygroscopic substance is chosen which has a melting point lower than the vaporisation temperature.
Obviously, in the composition according to the present invention, the hygroscopic substance must not be urea or one of its derivatives.
Hydrotropic substances that can be used in the present invention are benzoic acid, brompheniramine maleate, chlorpheniramine maleate, nicotinamide and derivatives thereof, nipecotamide, N-dimethylacetamide, N-methyl-nicotinamide, N,N-dimethyl-nicotinamide, m-hydroxybenzoic acid, p-hydroxybenzoic acid, pheniramine maleate, pyrogallol, resorcinol, penicillin potassium salt, salicylic acid, sodium hydroxybenzoate, sodium ascorbate, sodium benzoate, sodium gentisate, sodium glycinate, sodium salicylate, ibuprofen sodium salt, sodium m-hydroxybenzoate, sodium p-hydroxybenzoate, 4-sulfonic calix[n]arenes, cumene sulphonate, alkylbenzenesulphonates, butyl monoglycol sulphate, picolinamide, isonicotinamide, nicotinic acid, picolinic acid, isonicotinic acid, toluene sulphonate and xylene sulphonate.
Preferably the hydrotropic substance is chosen between cumene sulphonate, xylene sulphonate, toluene sulphonate, nicotinamide and nicotinic acid. These compounds have a high biodegradability, typically greater than 85% after 28 days, and are in fact considered readily biodegradable. Furthermore, the cumene sulphonate and the xylene sulphonate have the advantage of being inexpensive.
The mechanisms responsible for the hydrotropic solubilization are a function of the nature of the substance to be solubilized, and therefore is selective. In view of this selectivity, it is particularly advantageous for the composition to comprise a mixture of two or more hydrotropic substances.
It has been found that mixtures of hydrotropic substances in combination produce synergic effects in terms of increased solubility of substances having poor solubility and allow reduction of the quantities of hydrotropic substances to be used. The use of lower quantities of hydrotropic substances benefits both the eco-toxicological aspect and the economic aspect of the composition.
The hygroscopic substance is chosen from ε-caprolactam, glycols and polyglycols, or a mixture thereof. The ε-caprolactam is particularly preferable since, in addition to its high biodegradability (96% after 28 days) and its stability in an alkaline environment, just like polyglycols, it is solid at room temperature. The glycols and polyglycols instead have the advantage of maintaining their hygroscopic characteristics even in an acid environment, which makes them optimal candidates for printing with acid dyes.
From among glycols and polyglycols, polyethylene glycol in solid phase is preferred, namely the molecular mass of which is greater than 400 g/mol, as they allow to obtain good print results with acid dyes. Even more preferably, the polyethylene glycol has a molecular mass substantially equal to 1500 g/mol (also called PEG 1500), as in addition to the efficiency, it has the advantage of being less costly than other polyethylene glycols.
It should be highlighted that the composition according to the present invention can also be used in non-printing application processes that require concentrated impregnation baths (like pad-steam and pad-batch) where the solubilization and permeability of the latter play an important role.
It has been verified that for substituting the urea with a concentration equal to 100 g/kg (in respect to the total weight of the composition) it is possible to provide the hydrotropic substance has a concentration ranging between 15 and 50 g/kg, and that the hygroscopic substance has a concentration ranging between 40 and 80 g/kg, in respect to the total weight of the composition.
These concentrations of hydrotropic substances provide a good solubility for the components to be solubilized (the dyes). In addition to the substances mentioned above, the composition also preferably comprises other substances well known to the person skilled in the art and therefore not described in further detail, for example a thickening agent for thickening the fibre, an anti-reducing agent, an alkaline substance and/or an acid substance.
The mode of use of the composition according to the invention varies according to the type of printing in which it is used.
In textile rotary or flat screen printing, all the components of the composition are mixed together with the printing pastes which contain the dyes. Printing is then carried out with the mixture obtained.
With inkjet digital printing, on the other hand, the composition is applied on the textile substrate (pre-treatment) and the textile substrate is then printed with the printing inks, namely it is a step of applying one or more dyes onto the textile substrate.
Subsequently to the printing step, a fixation step can be carried out by means of vaporization or thermofixing, both alternatives producing comparable results.
Five examples of use of the composition according to the invention are given below.

Examples

In the following examples are described, showing the efficiency of the composition according to the present invention via a print test with cyan, magenta, yellow and black coloured dyes on silk, viscose and cotton by means of a digital MIMAKI JV33 plotter with a resolution of 720x720 Dpi.
Said prints are compared with the same prints obtained with known compositions comprising urea.

Example 1

The composition is used to prepare a cotton textile substrate for printing thereof with reactive dyes.
The prepared composition comprises:

Cumene sulphonate 25 g/kg

ε-caprolactam 65 g/kg

polyacrylate 100 g/kg

sodium bicarbonate 40 g/kg

Meta-nitro benzen sulphonate sodium 10 g/kg
The polyacrylate has the function of thickening the fibre, and the meta-nitro benzen sulphonate sodium is an anti-reducing agent. The sodium bicarbonate is the alkaline part and serves to disassociate the hydroxyl of the cellulose and to neutralise the HCl acid that forms during the reaction, with the chlorine released from the dye.
After a step of treating the substrate with the composition described above, the print is carried out by means of digital (inkjet) printing, and fixation takes place by means of vaporization.

Comparative example 1

The following composition is used for treating a cotton substrate for the printing thereof with a reactive dye:

Urea 100 g/kg

Polyacrylate 100 g/kg

Sodium bicarbonate 40 g/kg

Meta-nitro benzen sulphonate sodium 10 g/kg
The treatment, print and fixation processes are the same as those in example 1.

Example 2

The composition is used to prepare a viscose substrate, with reactive dyes.
The composition used comprises:

Nicotinamide 45 g/kg

ε-caprolactam 75 g/kg

Polyacrylate 100 g/kg

Sodium bicarbonate 40 g/kg

Meta-nitro benzen sulphonate sodium 30 g/kg
The treatment, print and fixation processes are the same as those in example 1.

Comparative example 2

The treatment of a viscose substrate is then carried out with the following composition, for the printing thereof with reactive dyes:

Urea 150 g/kg

Polyacrylate 100 g/kg

Sodium bicarbonate 40 g/kg

Meta-nitro benzen sulphonate sodium 30 g/kg
The treatment, printing and fixation processes are the same as those in example 1.

Example 3

The composition is used to treat a silk substrate, for the printing thereof with acid dyes.
The composition comprises:

Nicotinamide 30 g/kg

Polyethylene glycol 1500 50 g/kg

Hydroxyethyl cellulose 100 g/kg

Ammonium sulphate 40 g/kg
In this composition the hydroxyethyl cellulose acts as the thickening agent for the fibre, and the ammonium sulphate serves to increase the affinity of the dye with the fibre, releasing acid during the vaporization step.
The treatment, printing and fixation processes are the same as those in example 1.

Comparative example 3

The following composition is used for treating a silk substrate for the printing thereof with acid dyes.

Urea 1000 g/kg

Hydroxyethyl cellulose 100 g/kg

Ammonium sulphate 40 g/kg
The treatment, printing and fixation processes are the same as those in example 1.

Example 4

For each of the printed substrates an absorbance measure is carried out by means of a Datacolor spectrophotometer. For each colour of each type of substrate a comparison is provided, made between the absorbance obtained for the sample printed with the composition according to the present invention and the absorbance obtained for the reference sample, printed with the composition containing urea.

The ΔE has then been measured, which represents the difference between two colours (calculated according to the formula established in 1994), and the overall yield ratio, which represents the intensity of the colour obtained with the composition according to the present invention in relation to the intensity of the colour obtained with compositions containing urea. The values obtained are indicated in the table below.

Example 1			Example 2		Example 3
ΔE		Yield ratio (%)	ΔE	Yield ratio (%)	ΔE	Yield ratio (%)
Black	0.24	101.28	0.24	106.12	0.89	93.09
Cyan	0.21	101.39	0.24	99.78	0.95	102.24
Magenta	0.21	101.14	0.83	96.84	0.24	93.09
Yellow	0.83	105.68	0.97	102.72	0.24	98.33

As can be seen, all the ΔE are less than 1, which indicates that the difference between the colour obtained using the composition according to the present invention and the colour obtained using an equivalent composition with urea, is minimal. A ΔE less than 1 is a measure accepted by the market as being qualitatively good.
It can also be seen that the overall yield ratio is greater than 90%, which shows that the colour obtained using the composition according to the present invention has an intensity practically comparable to that of the colour obtained with a composition containing urea, even at times with a greater ratio (yield ratio values greater than 100%).
The results achieved show that the composition according to the present invention allow a comparable print quality to be obtained, if not at least, an improved quality, in respect to that obtained with compositions containing urea, at least in terms of colour and intensity yield.
A visual inspection also allows to note that the prints carried out by using the composition according to the present invention have a greater brightness than the prints carried out after a treatment with compositions containing urea. It is believed that the increased brightness is due to the improvement in the optical density of the dye, namely to a more uniform and wide spread distribution of the dye fixed in the fibre, such as to reduce, as far as possible, the background effect of the fibre which is always white.

Example 5

Subsequently to the fixation, a washing of the substrates is carried out.
For the cotton and viscose substrates, a first washing is carried out in a bath, with a ratio of 1:10, in a volume of water, with 2 g/L of specific detergent at a temperature of 90°C for a contact time of 120 seconds.
For the silk substrate, the first washing takes place in the same conditions with the exception of the temperature, which is 30°C.
For all the substrates, a second washing is carried out with the same procedure as the first one, and then a third washing is carried out by rinsing in water at room temperature with a bath ratio of 1:10.
The washing water is then collected and its absorbance is measured in the UV gamma by means of the spectrophotometer indicated above, so as to determine the concentration of dye dispersed in the washing water.
The absorbance values obtained are indicated in the following tables.

Cotton - first washing

	λ (nm)	Example 1	Reference example 1
Black	605	0.340	0.427
Cyan	675	0.249	0.252
Magenta	545	0.390	0.491
Yellow	425	0.313	0.388

Viscose - first washing

	λ (nm)	Example 2	Reference example 2
Black	545	0.235	0, 226
	615	0.248	0.241
Cyan	675	0.142	0.136
Magenta	555	0.327	0.310
Yellow	425	0.315	0.292

Silk - first washing

	λ (nm)	Example 3	Reference example 3
Black	600	0.041	0.040
Cyan	615	0.171	0.166
Magenta	550	0.050	0.049
Yellow	425	0.042	0.041

The results for the second and third washes are not presented as the quantity of dye released in the corresponding baths is negligible and cannot be detected.
The results obtained with the composition according to the present invention are comparable with those obtained with a composition containing urea. This shows that with the composition of the present invention the quantity of dye fixed in the fibre is substantially the same, in certain cases greater, as the quantity of dye fixed in the fibre with compositions containing urea.
The composition can also be extended to non-printing application processes that require concentrated impregnation baths, in particular of the pad-steam type, and when the fixation step is carried out by means of thermofixing after dyeing.
The intention of the present application is to protect the composition in any overall or partial form as an alternative and decisive solution to urea and its intrinsic properties with reference to the textile processes requiring the use thereof; in fact, the object of the invention is to provide a composition that can be used in textile printing, both rotary or flat screen printing and inkjet digital printing, with all the classes of reactive and acid dyes (which are the most commonly used on the market). The protection of the composition in any overall or partial form with extension to the other categories of dyes in which urea is required. The composition can be used in any overall or partial form with the extension (given its intrinsic properties) also to printing processes where urea is not normally used (as with disperse dyes, pigments and indanthrene), with reference also to non-printing application processes that require concentrated impregnation baths (like pad-steam and pad-batch) where the solubilization and permeability of the latter play an important role.
The composition in any overall or partial form can be included in the formulation of the printing inks.
In order to meet specific contingent requirements, a person skilled in the art may make numerous additions or modifications to the described embodiments of the composition for the treatment of fibrous materials according to the invention, or replace elements with other functionally equivalent ones, without departing from the scope of the attached claims.

Claims

A composition for printing fibrous materials, comprising at least one hydrotropic substance, excluding urea or a derivative thereof, and a hygroscopic substance.
The composition according to claim 1, comprising at least one hydrotropic substance chosen from the group consisting of benzoic acid, brompheniramine maleate, chlorpheniramine maleate, nicotinamide and derivatives thereof, nipecotamide, N-dimethylacetamide, N-methyl-nicotinamide, N,N-dimethyl-nicotinamide, m-hydroxybenzoic acid, p-hydroxybenzoic acid, pheniramine maleate, pyrogallol, resorcinol, penicillin potassium salt, salicylic acid, sodium hydroxybenzoate, sodium ascorbate, sodium benzoate, sodium gentisate, sodium glycinate, sodium salicylate, ibuprofen sodium salt, sodium m-hydroxybenzoate, sodium p-hydroxybenzoate, 4-sulfonic calix[n]arenes, cumene sulphonate, alkylbenzenesulphonates, butyl monoglycol sulphate, picolinamide, isonicotinamide, nicotinic acid, picolinic acid, isonicotinic acid, toluene sulphonate and xylene sulphonate.
The composition according to claim 2, wherein the hydrotropic substance is chosen from cumene sulphonate, xylene sulphonate, toluene sulphonate, nicotinamide and nicotinic acid.
The composition according to claim 1, 2 or 3, wherein the hygroscopic substance is chosen from ε-caprolactam, glycols and polyglycols.
The composition according to claim 4, wherein the hygroscopic substance is chosen from ε-caprolactam and polyethylene glycol with a molecular mass greater than 400 g/mol.
The composition according to one or more of the preceding claims, comprising the hydrotropic substance with a concentration ranging between 15 and 50 g/kg and the hygroscopic substance with a concentration ranging between 40 and 80 g/kg, in respect to the total weight of the composition, for substituting the urea with a concentration equal to 100 g/kg.
A use of the composition according to claim 1 for printing with fibrous materials.
The use according to claim 7, wherein the print is carried out by a thermofixing step.
A paste for rotary or flat screen printing of fibrous materials, comprising the composition according to claim 1.
An ink for digital printing of fibrous materials, comprising the composition according to claim 1.
A method for printing fibrous materials, comprising the steps of:
a. treating a fibrous material with the composition according to claim 1;

b. applying one or more dyes on the fibrous material, simultaneously or subsequently to step a.