DD299235A7 - METHOD FOR PRODUCING FIBERS FROM REGENERATED CELLULOSE - Google Patents

Abstract

The invention relates to the production of regenerated cellulose fibers with high strength and high wet modulus. The fibers produced have cotton-like properties and, when blended with other fibers, ensure very good processing properties. According to the invention, a defined viscosity range is set for the viscose to be spun, which is between 4 and 6.5 Pas. This achieves the maximum stretching limit and makes the spinning process stable. {Regenerated cellulose fibers; Strength; Naszmodul; sPINNING; Viscose; Viskositaetsbereich; cotton-like properties; stable spinning process}

Description

Field of application of the invention

The invention relates to the production of fibers of regenerated cellulose of high Fi 'Igkeit and high wet modulus with cotton-like properties, which also show very good processing properties when blended with other fiber types.

Characteristic of the known state of the art

It is known to use modifier-containing viscose containing 5-7.5 wt. Parts of alpha-cellulose, 5-7 wt. Parts of alkali and 30-40 wt. Parts of carbon disulfide (based on alpha-cellulose) each in% for the production of high-grade regenerated fibers with high strength and high wet modulus , which are spun in spinning baths with sulfuric acid, zinc sulfate and sodium sulfate. The viscosity of the viscoses to be spinned is given as 80 to 105 falling-seconds (corresponding to 10-12.5 Pa · s).

This is followed by stretching, fixing and aftertreatment of the tow in separate baths.

As modifiers are mainly secondary amines, polyalkylene oxides, Fettaminoxothylate, Aminoxethylate and FetUlkoholoxethylate known: (DD 253261).

The data on optimum spinning bath compositions vary widely with respect to sulfuric acid, sodium sulfate and zinc sulfate and an addition of surfactants that significantly improve the spinnability of the viscose.

Essential quality features of the viscose fiber produced are determined by the spinning process, whereby in addition to an optimum solution state of the viscose and the technological parameters of the manufacturing process, the rheological processes in the Fadonbildung exert an influence on the stability of the spinning process.

An essential factor in influencing the stability of the spinning process and the stretching capacity of the viscose to be spun is the viscosity. The known compounds have a viscosity level which, when using block nozzles with a 40000 hole, leads to an impairment of the spinning stability and the stretching capacity. The resulting fibers give lower strength and wet modulus values.

Object of the invention

The aim of the invention is to provide viscosity ranges which stabilize the spinning process when using modular nozzles with> 40000 holes and allow optimum stretching capability of the viscoses to be spun without additional expense.

Explanation of the essence of the invention

By the invention, the problem to be solved to produce fibers of regenerated cellulose with high strength and high wet modulus and drive through increasing the stretching ability a stable spinning process.

It has surprisingly been found that when spinning viscoses with block nozzles> 40000 holes and a hole diameter of 0.050 to 0.060 mm an optimum Viskositätsbeiöich must be set so that the stretching capacity is utilized to the maximum and a stable spinning process can be performed.

The viscosity range is 4 to 6.5 Pa · s.

Above the viscosity range, the stretching limit of the viscose to be spun decreases, and cable breaks occur in the stretching bath or in the fixing bath.

Below the viscosity range, the alkali solubility of the fibers increases; the spinning process is affected by spit formation on the nozzle surface.

The viscosity is preferably adjusted by varying the average polymerization gradient of the viscose to be spun.

embodiments

The invention will be explained below with reference to exemplary embodiments:

From a pulp are viscose with 6 parts by weight alkali, 6 parts by weight alpha cellulose and 35 parts by mass carbon disulfide (based on alpha cellulose) in each case in% with the addition of modifier mixture of ethoxylated amines

and polyethylene glycols and spun at a gamma value of 50 through spinnerets with a total number of holes of 56580 hole and a hole diameter of 0.055 mm in spinning baths of various composition at 32 ⁰ C. The fiber cable is then stretched and post-treated.

Belpslel 1 (comparative example without viscosity range according to the invention) The viscosity of 56580-Lochdüson (hole diameter 0.055 mm) at a speed of 23rn / min to

Spun viscose is 11 Pa · s.

Example 2

The procedure is as in Example 1.

The viscosity of the above Example 1 under conditions of the viscose to be spun is 5,2Pa s at 2O ⁰ C.

Example 3

The procedure is as in Example 1.

The viscosity of the above Example 1 under conditions of the viscose to be spun is 4Pa s at 2O ⁰ C. The spun according to the examples show the following viscoses stretching behavior:

example

maximum stretch ratio%

stable stretching ratio%

1 (comparative example) 2 3

126

142-146 142-140

112

128 128

The fibers produced have the following textile-physical characteristics:

example 2 Titers in tex feinheitsbez. tensile force wet wet modulus Alkali- 3 inmN / tex 208 mN / tex Solubility in dry 5% icerNaOH 1 (comparative 0,151 330 245 886 5.3 example) 239 0,149 345 1141 5.7 0,150 340 1148 6.2

Claims (1)

-1- 29b 235 Claim: A process for the production of fibers of regenerated cellulose with high strength and high wet modulus by spinning viscose in a sulfuric acid, zinc sulfate and sodium sulfate-containing spinning bath with subsequent stretching of the tow in a weakly sulfuric stretching bath and / or fixing in a sulfuric acid fixer, using spinnerets with a number of holes> 40000, characterized in that the viscose to be spun has a viscosity of 4 to 6.5 Pa · s.