DE102007043109A1 - Starch-based pressure thickener for the reactive pressure - Google Patents

Abstract

The present invention relates to a reactive pressure printing thickener which contains at least one starch in a proportion of at least 50% by weight, based on the total weight of the printing thickener, wherein the starch has a DS value of 0.2 to 0.6 and crosslinked with 0.05 to 0.50 vol.% of a crosslinking agent; as well as its use.

Description

The The present invention relates to a pressure thickener for Reactive printing and its use.

Under The term "textile printing" is understood locally limited pattern dyeing of Textiles, which are carried out by different methods can be both synthetic and natural Textiles can be used.

The Various printing methods are known, for example Direct printing, etching pressure, reserve pressure. Also very different Printing techniques, such as rouleaux printing, planographic printing, rotary-film printing, Transfer printing, inkjet printing, etc. are available.

each Printing technique is done by a special procedure, including printing, drying, steaming and washing, finally to get the finished printed product.

Orderly Dye classes are essentially different when printing between pigment pressure, reactive pressure, dispersion pressure and cooling pressure. Approximately 30% of all printed fabrics are printed worldwide using the reactive printing process prepared so that the reactive pressure in terms of quantity comes second after pigment printing.

reactive dyes may be present in the presence of their reactive groups of alkali (soda) make chemical bonds with a cellulose fiber, whereby particularly good frictional and wet fastness properties are achieved. In the alkaline medium, the reactive groups react with the hydroxyl groups the cellulose. However, the dyes also react with the hydroxyl groups the water and any existing pressure thickener, the appropriate viscosity for the used To provide reactive dyes. For this reason, next to synthetic products that are free of OH groups in the state The technique so far predominantly alginate as a natural Raw material used for printing thickener, since there is also no contains free hydroxyl groups. Other natural Pressure thickeners, for example, based on starch are constructed, however, react with the dyes. this leads to finally to a handle hardening on the goods and a deterioration of rubbing fastness.

There Alginates increasingly in the food sector be used and the demand for alginates is steadily increasing, it comes here easy to raw material bottlenecks. Further are the prices for alginates are about 3 to 4 Euro / kg right high. There is currently no alternative to alginates based a natural raw material for reactive pressure would be suitable for forming a pressure thickener.

It is therefore an object of the present invention, the disadvantages to overcome from the prior art and a pressure thickener essentially based on a natural raw material, which can be used for reactive printing. Especially is a reaction of the pressure thickener with the reactive dyes be avoided, the pressure thickener for all printing techniques, such as planographic printing and rotary film printing, should be suitable. This is especially true for a possible use in stencil printing techniques, the big demands the purity of the products used.

The Task is solved by a pressure thickener for Reactive pressure, which is at least one strength in one part of at least 50% by weight, based on the total weight of the printing thickener, wherein the starch has a DS value of 0.2 to 0.6 and crosslinked with 0.05 to 0.50% by volume of a crosslinking agent. The DS value describes the degree of substitution (Degree of Substitution DS) of the hydroxyl groups per glycose unit of starch, as is known to those skilled in the art.

there it is preferred that the starch in a proportion from 50 to 99 wt.%, preferably 50 to 80 wt.%, more preferably 65 up to 75% by weight, based on the total weight of the printing thickener, is present.

Also it is suggested that the starch prefers one DS value between 0.3 and 0.4.

Also preferably, the starch is from 0.2 to 0.4% by volume of the crosslinking agent networked.

Especially preferably the starch is corn starch.

A Embodiment is characterized in that the Etherifying agent sodium monochloroacetate and / or monochloroacetic acid is and / or the crosslinking agent is epichlorohydrin.

Also It is suggested that the pressure thickener be mechanical is modified, preferably by roll drying.

Especially preferred is that the pressure thickener in addition to the at least one strength at least one more natural and / or synthetic pressure thickener.

The further thickeners may be selected from sodium polyacrylate, Sodium alginate and mixtures thereof.

According to the invention also the use of the printing thickener in combination with reactive dyes.

there is the use on natural fibers, such as cotton and viscose, preferred.

Surprisingly it was found that a pressure thickener on Starch base be provided for reactive printing can, with the starch highly crosslinked and highly etherified is excellent when used in a reactive printing process Print results leads. These print results include a high color depth, sharp contours, a level color loss and a soft touch of the substrate.

Of the Basic building block of all strengths is the α-amylose, wherein each amylose molecule is within the starch chain each having three free, reactive hydroxyl groups. These hydroxyl groups are prepared by suitable modification, i. H. by etherification and / or crosslinking, unreactive so that the strengths in response to the Reactive dyes in particular no grip hardening can cause more.

Printing thickener should have the highest possible viscosity, However, especially for stencil printing, be easily filterable, otherwise the templates after a short time would clog. By using the highly networked and highly etherified starches, it is now possible according to the invention optimum viscosity and filterability for to provide the pressure thickener. A preferred embodiment of the invention, in the viscosity and filterability yet are further improved, characterized by the fact that next the starch (in a proportion of at least 50 wt .-%) yet another different natural and / or synthetic Thickener is used. Such a further thickener For example, sodium polyacrylate, sodium alginate or mixtures be, with a particularly preferred pressure thickener 70% by weight of starch and 30% by weight of the further thickener consists.

Further has been shown that corn starch is likely due to their small grain size and short structure especially good for use as a pressure thickener suitable is. It is also preferred that the used Starch is cold water soluble.

Appropriate So far, starch-based products have only been very successful small percentage used for the reactive pressure.

Further Features and advantages of the invention will become apparent from the following detailed description of embodiments, on the invention should not be limited.

Corn starch derivatives with varying degrees of etherification and crosslinking were prepared and its viscosity via a Brookfield viscometer measured in an 8% concentration as well as the filtration value.

to Determination of viscosity will be 460 g of tap water in Weigh out a 1 l scale and then stir with a Double bar stirrer and a Heidolph stirrer 40 g of product added. The solution is allowed to stand for 15 minutes 800 rpm solved. It is measured with a Brookfield viscometer Type RVT at 20 rpm and 20 ° C.

To determine the filterability or the filtration value, 100 g of product are dissolved in 1,900 g of tap water for 1 hour at 700 rpm (double-bar stirrer and Heidolph stirrer). Subsequently the solution rests for 1 hour. Thereafter, the solution is filtered off under vacuum through a 45 μm sieve. Time and negative pressure are measured.

The results for the individual corn starch derivatives are given below in Table 1. Table 1 also shows the quantities of products 1-6 used in the printing paste. Table 1 product Vol .-% epichlorohydrin Amount of sodium monochloroacetate Brookf. Visc. 8% in mPa · s filtration value amount used 1 0.25 8 mol 380 240 '' (0.8 bar) Not printed 2 0,375 8 mol 205 240 '' (0.8 bar) 140 g / kg 3 0.20 8 mol 350 170 '' (0.8 bar) 120 g / kg 4 0,038 10 mol 16800 28 '' (0.2 bar) 55 g / kg 5 0,038 15 mol 12200 28 '' (0.2 bar) 62 g / kg 6 0,038 20 mol 9000 30 '' (0.2 bar) 70 g / kg

For all corn starch derivatives were reactive pressure tests pure cotton, with a laboratory print table Zimmer and a fixer from the company Mathis was used. The quality of the print was 100% CO with a design of 002 / 1-60 mesh.

The printing paste was composed of 5 g / kg Revatol ^® NS (dyeing and printing products, Clariant), 25 g / kg sodium carbonate, 100 g / kg urea, printing thickener with a specified in Table 1 and 100 g / kg Cibacron ^® Turquoise Blue P-GR 50% as a dye, the remainder being water. The printing was carried out on a laboratory printing table from Zimmer with a squeegee of 10 mm, a magnetic stage of 2/3 and a speed of 1.5 m / minute. The steam was fixed at a temperature of 103 ° C (saturated steam) for a period of 7 minutes. A pressure wash was then performed in three consecutive baths. The first wash was done cold for 3 minutes without additives, the second wash in a bath of 95 ° C for 3 minutes with an addition of 1 g / l Kieralon ^® DB (washing and wetting agent, BASF). A third wash was finally done cold for a minute with no additives.

For All products have received good printing results. It showed itself that the product with the number 2 the best printing results on pure cotton supplied. In particular, were a high color depth, sharp Contours, a level color loss and a soft touch of cotton receive. However, the viscosity and the filterability were still capable of improvement.

These Disadvantages could by adding other natural and / or synthetic thickener are eliminated.

example 1

One Crosslinked corn starch ether was prepared by reaction of corn starch with 10 moles of sodium monochloroacetate (DS: 0.4) and 0.375% by volume epichlorohydrin. This was 2,000 g of corn starch suspended in 2,400 ml of tap water and 500 ml of 1 N NaOH was added. The resulting slurry was heated to 40 ° C in a water bath. 7.5 ml of epichlorohydrin (0.375% by volume) were added and 24 hours at 40-42 ° C with the corn starch implemented. Then, 1,165 g (10 mol) of sodium monochloroacetate was added and the slurry gelatinized with 550 ml NaOH (50%). The mass obtained was on a roller with 3 rolls at 2-3 up, and 7-8 bar steam pressure dried. The product was subsequently transferred over sieved a sieve of 2 mm.

70 % By weight of the crosslinked and roller-dried corn starch ether thus obtained were mixed with 30 wt .-% sodium polyacrylate and together a roll dried. The Brookfield viscosity was measured as above and was 20,000 mPa · s while the filterability values of <60 seconds at 0.2 bar. The insertion amount of the corn starch ether thus prepared in the printing paste was 50 g / kg.

For the printing thickener thus obtained, printing tests were carried out as described above and compared the results of the printing with a thickener based on 100% alginate. It was found that color depth, levelness and contour state of the pressure thickener according to the invention were better than with a Druckverdikkungsmittels based on 100% alginate. The handle was identical for both pressure thickeners. Furthermore, wet and dry rub fastnesses were measured with a Crockmeter ( Crockmeter model 255 by James H. Heal, Halifax, England, method ISO 105-A03 ) were compared for the inventive pressure thickener and the pressure thickener based on alginate. For measurement, printed areas of a cotton fabric to be tested were rubbed under controlled conditions against a white cotton fabric. The color of the abrasion was compared with the gray scale and graded.

ever the smaller the value, the worse the authenticity. The Scale ranges from 1 to 5.

The results of the wet and dry rubfastness tests are shown in Table 2. Table 2 Pressure-thickening agent according to the invention 100% alginate Rubbing fastness dry 5 5 Rubbing wet 4 4-5

As can be seen from Table 2 shows the inventive Printing thickening agents wet and dry rubbing fastnesses, very good with those for a pressure thickener can be compared on the basis of 100% alginate.

In as described above and in the claims Features of the invention can be used individually as well as in any combination for the realization of the Invention in their various embodiments essential be.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited non-patent literature

• Crockmeter Model 255 from James H. Heal, Halifax, England, Method ISO 105-A03 [0036]

Claims (12)

Pressure thickener for reactive pressure, that at least a strength in a proportion of at least 50% by weight, based on the total weight of the printing thickener, contains, where the strength has a DS value of 0.2 to 0.6 and 0.05 to 0.50% by volume of a crosslinking agent is networked. Pressure thickener according to Claim 1, characterized the starch is present in a proportion of 50 to 99% by weight, preferably 50 to 80 wt .-%, more preferably 65 to 75 wt .-%, based on the total weight of the pressure thickener, is present. Pressure thickener according to claim 1 or 2, characterized characterized in that the strength is a DS value between 0.3 and 0.4. Pressure thickener according to one of the preceding Claims, characterized in that the starch is crosslinked with 0.2 to 0.4% by volume of the crosslinking agent. Pressure thickener according to one of the preceding Claims, characterized in that the starch Corn starch is. Pressure thickener according to one of the preceding Claims, characterized in that the etherifying agent Sodium monochloroacetate and / or monochloroacetic acid. Pressure thickener according to one of the preceding Claims, characterized in that the crosslinking agent Epichlorohydrin is. Pressure thickener according to one of the preceding Claims, characterized in that it is mechanical is modified, preferably by roll drying. Pressure thickener according to one of the preceding Claims, characterized in that it is next to the at least one strength at least one more natural and / or synthetic thickener. Pressure thickener according to claim 9, characterized characterized in that the further thickener selected is made of sodium polyacrylate, sodium alginate and mixtures thereof. Use of the pressure thickener after a of claims 1 to 10 as a pressure thickener in Combination with reactive dyes. Use according to claim 10 on natural Fibers, such as cotton and viscose.