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Title:
THICKENER FOR TEXTILE PRINTING PASTE
Document Type and Number:
WIPO Patent Application WO/2005/080668
Kind Code:
A2
Abstract:
The present invention deals with a thickener for printing pastes based on polygalactomannan derivatives and an enzyme, and with textile printing pastes containing said thickener; the printing pastes of the invention have the property of imparting a better uniformity of dye distribution on fabrics, as demonstrated by an improved visual effect noticeable on the final article.

Inventors:
Pfeiffer, Ugo (via Raffaello Sanzio 31, Milano, I-20149, IT)
Rossi, Alessio (Via per Besnate 39, Gallarate, I-21013, VA)
Menabue, Dario (Via Boffalora 38, Daverio, I-21020, VA)
Pericu, Piera (Via Barnaba Oriani 55, Milano, I-20156, IT)
Coarezza, Roberto (Via Mazzini 5, Castronno, I-21040, VA)
Li Bassi, Giuseppe (Via Stretti 4, Gavirate, I-21026, VA)
Application Number:
PCT/EP2005/050700
Publication Date:
September 01, 2005
Filing Date:
February 17, 2005
Export Citation:
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Assignee:
Lamberti, Spa (via Piave 18, Albizzate, I-21041, VA)
Pfeiffer, Ugo (via Raffaello Sanzio 31, Milano, I-20149, IT)
Rossi, Alessio (Via per Besnate 39, Gallarate, I-21013, VA)
Menabue, Dario (Via Boffalora 38, Daverio, I-21020, VA)
Pericu, Piera (Via Barnaba Oriani 55, Milano, I-20156, IT)
Coarezza, Roberto (Via Mazzini 5, Castronno, I-21040, VA)
Li Bassi, Giuseppe (Via Stretti 4, Gavirate, I-21026, VA)
International Classes:
D06P1/48; (IPC1-7): D06P/
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Claims:
Claims
1. Thickener for textile printing paste containing one or more polygalactomannan derivatives and a protease.
2. Thickener for textile printing paste according to Claim 1, in which the protease is a serine protease of the subtilisin family of microbial origin.
3. Thickener for textile printing paste according the Claim 1 or 2, in which the polygalactomannan derivatives are chosen among depolymerised guar, hydroxyethylguar, hydroxypropylguar, carboxymethylguar.
4. Thickener for textile printing paste according to Claim 3, in which the polygalactomannan derivatives in aqueous solution have a Brookfield viscosity at 20°C and 20 rpm of about 20.000 mPa*s at a concentration comprised between 1 and 12% by weight.
5. Thickener for textile printing paste according to Claim 4, in which the polygalactomannan derivatives in aqueous solutions have a Brookfield viscosity at 20°C and 20 rpm of about 20.000 mPa*s at a concentration between 7 and 12% by weight.
6. Thickener for textile printing paste according to one of the previous claims, containing from 40 to 99.5% by weight of one or more polygalactomannan derivatives and from 0.5 to 5% by weight of a protease, the eventual complement to 100 being accounted by one or more polymers having thickening function, chosen among alginates, starch and its derivatives, tamarind derivatives, synthetic polymers, cellulose derivatives.
7. Thickener for textile printing paste according to Claim 6, containing from 0.8 to 2% by weight of a protease.
8. Thickener for textile printing paste based on acid dyes containing one or more polygalactomannan derivatives and a protease, wherein the polygalactomannan derivatives in aqueous solution have Brookfield viscosity at 20°C and 20 rpm of about 20.000 mPa*s at a concentration comprised between 1 and 12% by weight and are chosen among depolymerised guar, hydroxyethylguar, hydroxypropylguar, carboxymethylguar, and the protease is a serine protease of the subtilisin family of microbial origin.
9. Thickener for textile printing paste based on acid dyes according to Claim 8, containing from 95 to 99.5% by weight of one or more polygalactomannan derivatives and from 0.5 to 5% by weight of a protease.
10. Thickener for textile printing paste based on acid dyes according to Claim 9 containing from 0.8 to 2% by weight of a protease.
11. Textile printing paste containing one or more polygalactomannan derivatives and a protease.
12. Textile printing paste according to Claim 11, wherein a. the protease is a serine protease of the subtilisin family of microbial origin and is present in quantity comprised between 0.015 and 0.35% by weight; b. the polygalactomannan derivatives are chosen among depolymerised guar, hydroxyethylguar, hydroxypropylguar, carboxymethylguar having in aqueous solution a Brookfield viscosity at 20°C and 20 rpm of about 20.000 mPa*s at a concentration comprised between 1 and 12% by weight, and are present in quantity comprised between 1 and 7% by weight in the printing paste.
13. Textile printing paste according to Claim 12, containing from 2 to 10% by weight of an acid dye.
14. Textile printing paste according to Claim 13, further containing one or more polymers having thickening function chosen among alginates, starch and its derivatives, tamarind derivatives, synthetic polymers, cellulose derivatives.
Description:
Description THICKENER FOR TEXTILE PRINTING PASTE Technical field [0001] The present invention deals with a thickener for printing pastes based on polygalactomannans derivatives and an enzyme, and with textile printing pastes containing said thickener.

[0002] Specifically, the enzyme useful for this invention is a protease and the polygalactomannans derivatives are those commonly utilised in textile printing, such as depolymerised, hydroxyalkylated or carboxymethylated polygalactomannans.

[0003] The fabrics printed with the textile printing pastes of the present invention show a better uniformity of dye distribution, as demonstrated by an improved visual effect noticeable on the final article.

Background Art [0004] Textile printing pastes serve to transfer dyes onto the fabric in a controlled way through a silk-screen, in order to have the correct formation of the desired pattern and decoration.

[0005] The textile printing paste composition is critical and largely determines the quality of the final article.

[0006] Printing pastes are prepared by solubilising a thickener in water and, successively, by adding the dye and other possible chemical auxiliaries useful to the process (such as pH regulators, antifoam agents, stabilisers and others) and have a solid content comprised between 7 and 20% by weight.

[0007] Commonly used thickeners are mainly composed by one or more water soluble natural or semisynthetic polymers of varying molecular weight, such as starch and its derivatives, alginates, polysaccharides from tamarind kemels, cellulose derivatives, polygalactomannans in general and polygalactomannans from guar seeds and their derivatives in particular.

[0008] Guar is the common name of a leguminosae family plant (Cyamopsis tetragonoloba) cultivated mainly in the arid and pre-desertic area between India and Pakistan.

[0009] The function of thickeners is to guarantee the viscosity to the paste in order to allow a better control in the pattern reproduction and sufficient fluidity for an easy passage through the silk-screen holes onto the fabric.

[0010] Polygalactomannans and their derivatives are among the most used thickeners for printing with acid dyes on fabrics made of fibers like wool, silk and polyamide.

[0011] The expert in the field acknowledges that polygalactomannans and their derivatives possess good characteristics of stability in the typical printing process and can be promptly removed in the final washing phase, but, compared to other thickeners, show inferior performance of superficial fixation and homogeneous distribution of the dye.

[0012] These problems, which appear more or less prominent depending on the pattern and on the depth of the desired colour, are extremely undesirable in the case of textile printing of valuable, high quality textiles articles.

Disclosure of Invention [0013] It has now been found that one of the causes of colour dishomogeneinity is the formation of microscopic aggregates in the printing paste, that, once deposed on the fabric, give rise to spots and dots thus affecting the dye yield and the uniformity of printing (for the sake of brevity, this phenomenon will be from now on referred to as"dotting") [0014] It has also been surprisingly found that a textile printing thickener containing one or more polygalactomannan derivatives and an enzyme, in particular a protease, permits to obtain printing pastes free from dotting.

[0015] Due to their natural origin, commercially available polygalactomannans always contain a variable amount of proteins (usually comprised between 2.5 an 10% by weight) deriving from the germ of the guar seed, that is not possible to remove before or during milling of the vegetable structure containing them.

[0016] A possible cause of dotting is that these proteins are potentially able to combine with acid dyes, thus forming complexes, and therefore can aggregate the colour in microscopic masses.

[0017] It is therefore an essential object of the present invention a printing paste thickener containing one or more polygalactomannan derivatives and an enzyme having proteolytic activity.

[0018] The enzyme useful for the present invention is a serine protease of the subtilisin family of microbial origin, for example a protease chosen among: Purafect 4000G and Purafect 4000E by Genencor International ; Alkalase, Durazym, Savinase, Esperase by Novozymes.

[0019] The polygalactomannan derivatives useful for the present invention are depolymerised guar (depolymerised either by alkaline hydrolysis or by oxidation), hydroxyethylguar, hydroxypropylguar, carboxymethylguar having viscosity measured by Brookfield viscosimeter at 20°C and 20 rpm of about 20.000 mPa*s at a concentration comprised between 1 and 12 % by weight, preferably between 7 and 12% by weight.

[0020] The polygalactomannans derivatives are those normally available on the market for use in the textile printing sector, for example they are commercialised by Lamberti SpA and Cesalpinia Chemicals SpA with the trade names of Printex and Indalca respectively.

[0021] The textile printing thickener of this invention contains preferably from 40 to 99.5% by weight of one or more polygalactomannan derivatives and from 0.5 to 5% by weight, preferably from 0.8 to 2% by weight, of a protease, the eventual complement to 100% being accounted by one or more polymers commonly used in textile printing pastes and having thickening function, such as alginates, starch and its derivatives, tamarind derivatives, synthetic polymers, cellulose derivatives.

[0022] The thickener according the present invention revealed itself particularly useful for the preparation of printing pastes containing acid dyes.

[0023] In this case, the thickener contains from 95 to 99.5% by weight of one or more polygalactomannan derivatives and from 0.5 to 5% by weight, preferably from 0.8 to 2% by weight, of a protease.

[0024] A textile printing paste containing one or more polygalactomannan derivatives and an enzyme forms a further essential object of this invention.

[0025] Particularly, the printing paste contains a serine protease of the subtilisin family of microbial origin in a quantity comprised between 0. 015 and 0.35% by weight and from 1 to 7% by weight of one or more polygalactomannan derivatives chosen among depolymerised guar (both depolymerised by alkaline hydrolysis or by oxidation), hydroxyethylguar, hydroxypropylguar, carboxymethylguar.

[0026] The polygalactomannan derivatives useful for the preparation of the textile printing pastes of the present invention are, in particular, those that in aqueous solution have a viscosity, measured by a Brookfield viscosimeter at 20°C and 20 rpm of about 20.000 mPa*s at a concentration comprised between 1 and 12% by weight, preferably between 7 and 12% by weight.

[0027] The textile printing paste according the invention can further contains one or more polymers having thickening function, chosen among alginates, starch and its derivatives, tamarind derivatives, synthetic polymers, cellulose derivatives, preferably in a quantity not higher than 4% by weight, and one or more additives among the ones commonly used for the formulation of textile printing pastes.

[0028] Textile printing pastes of the invention can be prepared according to the usual procedures, by slowly adding the thickener to water, under mechanical stirring, until complete dissolution is achieved, and by adding to the thickener solution so obtained the specific auxiliaries (pH regulators, antifoam, and so on) and the dye, and finally by adjusting the water content to the desired volume.

[0029] Preferably, the textile printing pastes according the present invention contain from 2 to 10% by weight of an acid dye.

[0030] The normal operating conditions used for the preparation of printing pastes permit to the thickener of the present invention to act as viscosity enhancer while avoiding dotting.

[0031] According to an essential aspect of the present invention the presence of an enzyme in the printing pastes has no negative effect on the printed article at the end of the printing cycle.

[0032] The commonly used drying and dye fixing conditions guarantee the complete inactivation of the enzyme and its transformation into soluble products that are eliminated from the printed fabrics during the final washing phase, along with the products derived from the proteins they were able to decompose.

[0033] Example 1.

[0034] Printing paste preparation (Paste 1).

[0035] a. Thickener preparation.

[0036] A thickener is prepared by dry mixing: [0037] 990 g of Printex PS10 (depolymerised hydroxyethylguar commercialised by Lamberti SpA, having Brookfield viscosity at 20°C and 20 rpm of about 16.000-20. 000 mPa*s at 7% by weight) [0038] 10 g of Purafect 4000E [0039] b. Mother paste preparation.

[0040] 90 g of the thus prepared thickener are added, under mechanical stirring, to 910 g of water and let under stirring until complete dissolution (40').

[0041] The mother paste is let to rest for about half an hour.

[0042] c. Dye solution preparation.

[0043] 50 g of Blue Tiacidol RAW 200% (acid dye commercialised by Lamberti SpA) are weighed in a glass and 50 g of thiodiglycol and 60 g of urea are then added and made into a paste. Boiling water is poured into the glass under stirring to reach 1000 g.

[0044] The solution is filtered on a polyester cloth of 54 micron.

[0045] d. Printing paste preparation (Paste 1).

[0046] 600 g of the mother paste are poured into a glass and 400 g of the dye solution are added while stirring; 10g of (NH4) 2SO4 are then added always under stirring in order to regulate the pH in the colour fixing phase.

[0047] Example 2 (comparative).

[0048] Printing paste preparation (Paste 2).

[0049] A printing paste is prepared proceeding exactly as described in the Example 1, but using for the preparation of the mother paste a thickener made only by Printex PS10 (Paste 2).

[0050] Applications tests.

[0051] A silk fabric is printed side by side with Paste 1 and Paste 2 by using the same silk screen and a Zimmer laboratory printing machine. The fabric is dried at a temperature of 90°C for 1 minute in an oven. The colour is fixed in an Arioli vaporising machine at 102°C for 40 minutes. The fabric is washed at 30° in the presence of soap. The printed fabric is dried and ironed.

[0052] The results of the printing test are evaluated visually by observing with the naked eye that the side printed with Paste 1 presents better homogeneity and brilliancy of colour compared to the side printed with Paste 2.

[0053] By analysing with a microscope or by a lens at 24 magnifications it can be observed that the dishomogeneinity and the minor brilliancy of the side printed with Paste 2 is caused by the presence of small colour aggregates not homogeneously distributed on the fabric.

[0054] A sample of fabric printed with Paste 1 is spread out on a flat surface and fixed in such a way as not to form creases, then suitably lighted with reflected light from a halogen lamp and a picture of 0.5 cm2 of printed fabric is obtained using a professional camera with a 40x magnification lens. The picture is digitised and visualised by a personal computer and further zoomed in.

[0055] The same is made with a sample of fabric printed with Paste 2.

[0056] In the sample printed with Paste 1 no defect due to gathering of colour or spots can be seen, while in the sample printed with Paste 2 more than 100 defects (spots) can be seen.