DE1594988A1 - Process for the uniform surface saponification of cellulose two and a half acetate woven or knitted fabrics - Google Patents

Description

· .... '. i GERMAN

ϊ ..:, 'L.,' ri:. * r ~ jJ rhodiaceta ag

1594988 ^: Freiburg LBr.

Freiburg i.Br., March 15, 1966

PATENT APPLICATION

Process for uniform surface saponification of Cellulose-2 ^ acetate woven or knitted fabrics

Woven or knitted fabrics made of cellulose-2x-acetate show for the processor and consumers have some unsatisfactory properties.

Due to the relatively low melting point of the acetate,

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the ironing ability of a cellulose-275-acetate is limited and can only be carried out properly at temperatures below 160, as the ironing becomes wavy at higher temperatures. Woven or knitted fabrics made of cellulose-2 ^ - acetate show a low abrasion resistance and a high electrostatic charge. In addition, if critical dyes are used, colored pieces have poor gas fading properties.

Cellulose triacetate is known to have similar unfavorable properties. In the case of cellulose triacetate, surface saponification (S-finish) managed to improve these properties. Then you also have Cellulose-2x-acetate tries to proceed in a similar way. This only had to be done flawless products if saponified to a very high degree so that the thread consisted largely of saponified cellulose and only contained a small core of Cellulo3e-2 - acetate. This However, thread no longer had the properties of cellulose acetate thread. Rather, it behaved like a rayon thread. It could no longer be dyed with acetate dyes (disperse dyes) and showed Due to the high saponification, a reduction in weight, since one normally saponifies up to acetyl numbers of about 40. To this day it has not succeeded

BAD OFüG'.NAL

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009844 / $ 168

to produce a cellulose acetate with only surface saponification was made. This is due to the much lower alkali resistance of cellulose - ^ - acetate compared to triacetate. With technical batch sizes, this lower alkali resistance always led to different degrees of saponification, so that under operating conditions constant color unevenness arose during the subsequent dyeing process, who consider goods treated in this way to be unsaleable. As such, a surface saponified 2-acetate thread is desirable because it is opposite to the heavily saponified acetate thread does not have the negative properties described above or only to a small extent.

A process for the surface saponification of cellulose-2-acetate, the avoids this error, and this is the subject of the present invention, is described below »

The wetted goods running on a jig with low tension first run through an alkali bath at room temperature, which is carefully increased from 1 to 2; 'j alkali content, based on the weight of the goods, with a liquor ratio to the goods used of 1: 3 to 1:10 , was brought. The liquor is now quickly heated to 80-100, but preferably 35-90 ° C (since an uncomfortable influence on the handle easily occurs at a higher temperature). A few passages of the goods are now carried out, the lye content being carefully increased to 3% to 4-5 / 3, always based on the weight of the goods. The running time of the goods in this bath is about 1 hour. The lye is drained off. The '- / are rinsed and then neutralized with acetic acid. It is then finished in the customary, not claimed process. The product obtained in this way shows a uniform surface saponification, which provides completely level color qualities. The acetyl number content drops by about 1.5 to 2 ^C ^ in the treatment described above * This low surface saponification is sufficient to greatly increase the ironing ability and the abrasion resistance. At the same time, the electrostatic charge on these V / are is reduced to a fraction. The exhaust gas fastness is also significantly better than in pieces that have not been pretreated in this way, especially for critical dyes.

009844/1655

⁹ BAO

The procedure described above is illustrated by the following example explained. However, this example in no way restricts the claimed method.

1200 m of lining made of cellulose acetate, raw material width 143 cm, weight per square meter approx. 95 g, acetyl number 54.8vö, are placed on a low-tension, high-speed jigger, e.g. the Poensgen system, with a running tension of 4-5 kg. The fabric is pre-wetted in water by 2 passes at 25-50, the pre-wet bath is drained off. If the liquor ratio to the goods used is 1: 5, a bath is prepared from 2.5 grams per liter of alcaline detergent and Vf ₀ (based on the weight of the arene) potassium hydroxide. The goods run through the bath once at 22 C. Now, by dissolving new potassium hydroxide, the alkali content of the liquor is doubled. A second passage of goods takes place. The bath is now quickly heated to 87 with standing goods. Two passages of goods follow. based on the weight of the goods, is 1 '/ » . A new passage of goods follows, then the alkali content is increased again so that it is finally 4 /» »based on the weight of the goods. With this alkali content, the goods now run through the for 1 hour The alkali solution is then drained off. It is rinsed with cold water. Subsequently, it is neutralized with cold acetic water, then washed with water. This is followed by dyeing and finishing according to the usual method. The product obtained has an acetyl number of 52.8 , ', their ironing resistance without curling, has increased from 170 to 233 °, the abrasion resistance is from J -.- .. J50 tours to Lochb ildunj has risen to 5I, JOO tours, the electrostatic charge has decreased from -17-- V, cn to -1000 Volt / approx.

BAD ORIGSNAL Q09844 / 1S55

Claims (2)

Claims ι 1) Process to obtain a Cellulo8e-2r acetate fabric or knitted fabric with improved ironing ability, increased abrasion resistance, reduced electrostatic charge, characterized in that the raw material after wetting is initially at room temperature and a liquor ratio between 113 to 1110 in a lye with slowly increasing alkali content, which is initially only increased to Zf _{0 of} the weight of the goods used, "then heated the lye to 80-100 °, and the goods are treated again for about 1 hour, the alkali content slowly increasing to 4-5 $ in the heated lye The weight of the raw materials used is increased and is only saponified on the surface. 2) Woven or knitted fabric made of cellulose-2; p-acetate improved ironing ability, increased abrasion resistance, reduced electrostatic charge} characterized in that this fabric or knitted fabric is saponified only on the surface by a lye solution so that the acetyl number is 1.5- 2 $ drops and the saponification is so even that a completely level dyeing can be carried out. 009844/1655 BATH ORIGINAL