DE336637C - Process for the production of easily bleachable cellulose fibers - Google Patents

Description

When carrying out the process according to patent 331802, it has been shown that, in order to achieve greater safety in the digestion and to maintain the greatest possible strength of the elementary fiber, especially for the production of finer yarn counts, it is advisable to undertake a further breakdown of the digestion stages described below. This ensures that this process can also be used in the cold. leads to a complete digestion, and that one can also work in simple open vessels, which on the one hand increases the reliability of the process, while on the other hand the system and operating costs are substantially reduced. This also enables a better observation of the progressing digestion and the interruption of the progressing reaction at the most favorable moment, before damage to the fiber in terms of strength or similar disadvantages can occur. Cleaning and washing are expediently inserted between the individual treatments, which promotes and accelerates the breakdown in individual cells while being extremely gentle on the fibers.
: The new procedure is in the following

Wisely exercised: ~ -

I. Pre-soaking: The raw or mechanically prepared plant substances are placed in water in open vats with a tilting device (or similar), similar to the hemp and flax roasting, and remain ^{soaked for 3 to 6 days at 30 to 50 °} C. until they appear in abundance from gas bubbles shows the beginning fermentation and the associated partial breakdown of the incrustations. This fermentation water is now drawn off and used again and again to prepare fresh raw material. The remaining fiber material is washed in the vat and then emptied by tilting it into the reaction vessels below, in which the further treatment is carried out. '

; II. Hydrolysis: The pre-soaked ^! As in the main patent, fibrous material is treated with weak, aqueous solutions of free (organic or inorganic) acids I or acidic salts of these acids for a few hours to two days at normal temperature up to a maximum of 30 to 40 ° C ' . .

This as well as the following processes can ■ also be used, among other things, in the paper ! and cellulose mills: usual turning or Make tumble cookers ". - '■:

- Should this hydrolysis be carried out with mild heat -mung take place, the required for this can low amount of heat from burning

the cockroaches or awns falling off in large quantities, which occur during mechanical processing fall off, be won.

When this hydrolytic treatment has ended, the acidic liquid is drawn off and used for the hydrolytic breakdown of fresh, pre-soaked material, while the remaining fiber material in the boiler with continuous supply of fresh water,

ίο possibly while turning slowly at the same time of the kettle is washed until the wash water no longer shows an acidic reaction. is When the washing is finished, the next one is left in the same digestion container Flow in digestion liquid, which takes effect at 40 to 50 ° C.

'When it comes to the production of the finest, completely insulated fibers, it has proved to be useful in extension of the main patent, the hydrolyzed and washed fibers between hydrolysis and the closure of the main patent a few hours to two days of exposure to an organic solvent suspend, and higher temperatures can be used, as such Solvents cannot have any damaging effect on the fiber. By the organic solvents will be which partially hydrolyze and loosened incrustations largely brought into solution, partly solve them. only detach themselves from the fiber, but remain suspended and settle as sludge-like masses to the ground after the solvent has been drawn off. After the treatment has ended, the solvent is drawn off and recovered and purified from suitable vessels by distilling off, while the dissolved and suspended substances remain as residue. The part still adhering to the fibers after pulling off the solvent is chosen from that of the following Digestion used liquor either by separation or by distillation recovered so that there are practically very little losses of the solvent. As suitable organic Solvents come e.g. B, ether, petroleum ether, alcohols, carbon disulfide, Acetone, carbon tetrachloride, petroleum, hydrocarbons, o. like. into consideration.

III. Digestion: The hydrolyzed and thoroughly washed, if necessary Fiber material cleaned by treatment with organic solvents is now subjected to a treatment by which the Enlargement effected in the most gentle way and the encrusting substances perfectly removed from the fiber and brought into solution. while at the same time the fiber bundles and strands are completely in the Individual cells are disassembled. This is done in the same boiler a treatment of the fiber material with diluted alkaline solutions (caustic soda, soda, Ammonium compounds, milk of lime and the like) at normal temperature or below a milder temperature Warming (30 to 50 ° C). The strength and duration of this unlocking depends on the nature of the fiber material. They must be chosen so that the fibers are not damaged and not brittle, but it is broken down into the individual toes. The time required varies between one to several days. The effect of these alkaline lyes is enhanced by adding small amounts of suitable organic solutions Solvents (alcohol, carbon disulfide, acetone, petroleum, hydrocarbons and the like), which is separated and recovered from the final liquors is significantly increased can be. The digestion liquors can be used repeatedly.

The effect can be increased by slowly rotating the bowl periodically, by a better and more even penetration of the fiber material with the Lye is achieved. Through this treatment, the fiber material can be completely absorbed into the Single toes open and the single toes can be perfect, exposed and the encrusting and cementing substances are completely dissolved out. -

The use of low temperatures and ordinary pressure in opposition to the main patent allows the progressive unlocking to be monitored continuously and to interrupt at the moment when the necessary degree of exposure has been reached, so that 'excessive chemical exposure and damage to the Fiber can always be avoided.

The broken down fiber material must pass through after the alkaline lye has been drained off suitable washing should be thoroughly watered. This will also cut it up favored in the individual toes. By applying the countercurrent principle, the Wash water enriched with alkali to such an extent that it is returned to the digestion system can be.

It can sometimes be useful and necessary to change the order of those described so far to change chemical effects and thereby the result of the digestion to influence.

As in the main patent, another follows Treatment, namely the:

IV. Isolation in exactly the same Way as is done in the main patent.

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After treatment with the insulating liquid, the fiber material is drained or suctioned off and the like freed from the excess liquid and then at low temperatures dried in loose fleece.

In this way a very light and loose fiber wool is obtained. Since you have the The degree of digestion can be influenced and interrupted as desired, is obtained by this method a fiber material that is used in flax and combed wool sip mill as well as especially in the cotton spinning mill according to the three-cylinder system as a full-fledged replacement the usual fibers can be spun, but of course also a high quality one Raw material for paper production, for the production of nitrocellulose and other cellulose esters.

Of particular importance for the value of this process is that the generated Fibrous material is characterized by particular strength and uniformity of the pile length. Furthermore, as a result of the gentle treatment at normal temperature or under mild warming, the cellulose becomes the fiber is not attacked at all, so that the highest yield of spinnable Fiber is achieved, which is again of great economic importance. It is It should also be emphasized that the temperatures used are those of the Mecbanian Treatment of falling pieces of wood (scraping and awning) to generate the necessary Quantities of heat are sufficient, so with this method no or only a very small amount Coal consumption is associated.

Finally it should be pointed out that for an expedient implementation of this Process the devices and their arrangement can and must be chosen so that almost no manual work is required, but the entire conveyance of the food, raw materials, lye, waste, etc. can be done mechanically and automatically.

Claims (2)

Patent Claims: ι. Modification of the manufacturing process of easily bleachable cellulose fibers as a cotton substitute that can be spun directly in cotton spinning and as a raw material for the manufacture of paper, nitrocellulose, etc. from various Plant fibers and waste, such as linseed and hemp seed straw, jute, reed ,. Nettle, potatoes, willow bark and the like according to patent 331802, characterized by a further Decomposition of the successive processes, in which the raw material namely: a) pre-soaking with water 30 to 50 ⁰ C through 3 to 6 days until fermentation begins, b) hydrolytic cleavage as in the main patent, if applicable Post-treatment with suitable organic solvents such as ether, petroleum ether, Benzene, alcohols, carbon tetrachloride, petroleum, hydrocarbons and the like, then c) the action of dilute alkaline solutions (caustic soda, soda, Ammonium compounds, quick lime and the like) as in the main patent, but at a lower level Temperature and normal pressure for one or more days, optionally with the addition of small amounts, more suitable organic solvents (ether, alcohols, carbon disulfide, acetone, petroleum, Hydrocarbons and the like) and finally d) as in the main patent from a few minutes to several hours with one Isolation solution is treated. 2. The method according to claim 1, characterized in that the under a to d The chemical treatments listed can be modified in any order, depending on the digestion to be achieved will.