DE1108849B - Process for the production of structures from regenerated cellulose - Google Patents

Description

The aim of the invention is a considerable reduction in gel swelling in order to produce structures of high utility value especially threads that can be made into cord. This is achieved by that the viscose as modifier 5 is a soluble salt of an N-substituted dithiocarbamic acid clogs.

Under "soluble salt of an N-substituted dithiocarbamic acid" is a salt of an N-substituted one Dithiocarbamic acid is to be understood as being at least 0.05% soluble in 6% aqueous sodium hydroxide solution is. To achieve this solubility, the modifying agents should not have a substituent with more than Contains 18 carbon atoms. Modifying agents that contain a higher substituent are to sparingly soluble. The preferred modifying agents are mono- or di-N-substituted dithiocarbamates, which contain no substituents with more than 10 carbon atoms and in which the nitrogen on one aliphatic carbon atom. The N atom can thus be a secondary or tertiary N atom.

To achieve favorable results, the dithiocarbamates in the viscose should be in one concentration of at least 0.05% must be present. Usually more than 0.75% is not necessary. A cheaper one The range is between 0.05 and 0.5 percent by weight. The optimal concentration of the modifier chosen depends on its effectiveness, molecular weight and stability. For example higher concentrations are required for sodium dibutyl dithiocarbamate than for sodium hexamethylene bis (dithiocarbamate). The optimal concentration also depends to some extent on process conditions, like the spinning speed, from; at higher spinning speeds should be less Modifying agents should be present so that the neutralization speed of the thread is only delayed so far how it will deal with the complete precipitation during its brief contact time with tolerates the precipitation bath.

The spinning baths contain sulfuric acid and 1 to 15% zinc sulfate. Zinc sulphate is essential, otherwise the dithiocarbamates have no effect on the spinning process and the thread properties. As a rule, sodium sulfate is still present. If necessary, further salts of divalent metals can be present which enhance the effect of the zinc sulfate, e.g. B. manganese sulfate, nickel sulfate or preferably iron (II) sulfate. In this case, smaller amounts of zinc sulphate can be used. The spinning bath expediently contains 4 to 12% sulfuric acid, 13 to 25% sodium sulphate and 1 to 15% zinc sulphate, a process for the production of structures
made of regenerated cellulose

Applicant:

EI du Pont de Nemours and Company,
Wilmington, Del. (V. St. A.)

Representative: Dr.-Ing. W. Abitz, patent attorney,
Munich 27, Gaußstr. 6th

Claimed priority:
V. St. v. America May 29, 1951

Melvin Adam Dietrich, Claymont, Del, (V. St. A.), has been named as the inventor

preferably with 1 to 5% iron (II) sulfate. The optimal one The amount of zinc sulfate appears to be between 3 and 10%. Modified viscose require to achieve with optimal properties, usually different acidities than the unmodified viscose. at Modification by dithiocarbamates can also be used in baths with high acidity, in which unmodified Viscous threads of poorer quality result, excellent threads are obtained. Most convenient the spinning takes place in a temperature range of 40 to 75 ° C. It is recommended that the To keep bath acidity as low as possible for a certain spinning speed so that one can achieved optimal properties. It is expedient in the precipitation bath to achieve maximum gel shrinkage and improved stretchability uses the highest possible solids content.

The passage of the threads through the primary bath can be 3.3 to 7.4 m. A Orientation of the still plastic threads take place. However, the preferred method is to use the To carry out stretching partially or completely outside of the primary bath in a secondary bath or a perform combined stretching in air and a hot bath. The secondary bath can be made up of water or of dilute sulfuric acid (1 to 3%), or it can have the same composition like the precipitation bath, but in greater dilution, z. B. in a quarter of the concentration of the Felling bath. The bath passage of the thread in the secondary bath can be 25 to 127 cm. the The temperature of the secondary bath is appropriate

109 617/421

3 4

between 50 and 100 ° C. Oven dried at 105 ° C and weighed to achieve high strength. The Ver-

the threads will increase by 20 to 100%. Preferential ratio of gel weight to cellulose weight (grams

80 to 100%> stretched. When using the gel per gram of cellulose) is called the gel swelling

The two-bath method is the name given to the freshly precipitated gel thread of the thread. The method can e.g. B.

expediently withdrawn at a speed, 5 by changing the spinning speed or the

that of the exit speed of the viscose from the bath passage or modified by stretching

Spinneret is equal to or less than this. The degree will, however, result in only minor fluctuations

the stretching depends on the desired thread properties - the gel swelling values of the thread. The acidity of the

shed. The spinning bath has some influence on the

Any viscose can be used. OK mood of the gel swelling.

You can z. B. made of wood pulp, cotton lint, mixed To determine the gel swelling of films made of the two or other types of cellulose, 0.38 mm thick, cast on a glass plate. The composition of the viscose can films from viscose in a 8.5 ° / ₀ sulfuric acid, vary widely. So she can z. B. a cellulose 17 <> / ₀ sodium sulfate and 10% zinc sulfate containing loose content of 4 to 10% or higher and an alkali 15 bath of 60 ⁰ C precipitated. Have a sample of coagu content of 4 to 9% or higher. The standardized film is in each case from the middle viscous industry, ie cut viscose with 5 to 7%, dried between blotting paper and cellulose and 4 to 7% alkali are preferred. weighed. The weighed samples are then carried out by The sulfidation can be washed free with 25 to 50% sulfuric acid and the salt of the bath, carbon (based on the recovered 20 dried overnight at 105 ° C and weighed again, bare, bone-dry cellulose) . When adding the gel swelling (grams of gel film per gram of cellu dithiocarbamates according to the invention can be higher loose), normal xanthate contents (higher saline film. The ratio of the gel points) in the viscose are used for the modified and the non-modified. With boiling swelling of the test sample to the gel swelling of the unmodisalting point above 5, the stretchability and fixed viscose film appears to be calculated and, as the gel, to improve the quality of the thread properties. Denoted by swelling ratio (for films).
To achieve salt points above 5 in unripened viscose, 30% or more carbon disulfide are required for gel swelling of those produced according to the invention. Whether the structure is very much reduced, and although this reduction is intended in the process according to the invention is accompanied by a noticeable improvement in the moderately unripened viscose, properties of the finished structures, in particular the substantial improvements in gel strength, are accompanied. The secondary swelling is also achieved with normally ripened viscose, which (water absorption of the dried structure) shows that the process according to the invention is markedly reduced.

is directly applicable in ongoing practice. Even if in terms of cross-section and surface

if, for example, a 32% CS ₂ and 25% sodium cyclo- 35 composition are used, those according to the invention differ

hexyl dithiocarbamate containing 7-6 viscose produced threads clearly different from other threads,

represents, so the viscose, as it is for normal viscose threads, which are made of unmodified viscose in one

It is customary to leave a mantle zone at a saline point of 4.5 (the xantho zinc bath is spun

genat 1.05%) matured. recognize which has a different swelling capacity in water

The dithiocarbamates can be used alone or below 40 as the core zone. The cross-sections of these threads add certain other, the modifying we- show deep and shallower notches in the edge, kung reinforcing connections are used. In the case of the threads spun according to the invention, the latter, however, also modifying sheath zone is much larger; the boundary between medium can be. Such connections are very blurred under the jacket and core, and the thread of other ether modifiers, such as ethoxy-45 has no noticeable notches or mono-ethanol, butoxy-ethanol, phenoxy-ethanol, methoxy-tungen, so that its surface is relatively smooth ethoxy-ethanol, Butoxy-ethoxy-ethanol, phenoxy-eth- is. Such threads are also described in the USA patents oxyethanol, tetraethylene glycol dimethyl ether, di-2,536,014, 2,535,044 and 2,535,045.
Ethylene glycol diethyl ether. Ethylene glycol diethyl ether, the threads produced according to the invention have triethylene glycol diethyl ether tetramethylene glycol di- 50 a higher resistance to fibers, ethyl ether or triethylene glycol dimethyl ether, which has at least 1% abrasion and soiling of sodium, an increased washing liquor to at least 6% , but above all a very high strength, and are not more than 0.5% soluble in the precipitation bath. A special feature of the threads is their high polyethylene glycol with a molecular weight of fatigue strength. The threads can generally be added at 300 to 1000 can also be added to the viscose modified with dithiocarbamates 55 instead of the usual threads made from regenerated cellulose. In some cases, but especially in the textile cases, the viscose can be used three or more Modifi- Industry and for tire reinforcement (tire cord). The decorating agents are added (see. Example 5). Combination of high strength with a large one

The gel swelling is spun at both fatigue resistance represents an essential tech-

Threads as well as cast films are intended. The 60 niche progress.

Numerical values for the gel swelling of threads were The invention is not only suitable for

obtained by the following method: The gel thread making threads but is general to the

was coming from the first conveyor roller and before the production of structures from regenerated cellulose

suitable for immersion in the second hot bath without stretching, e.g. B. films, tapes, caps and the like.

collected by placing it on cotton 65 for 3 minutes

gauze drained. The sample then became Example 1 for 5 minutes

centrifuged (3600 rev./min.), in a closed-A viscose with a content of 5% cellulose

ne bottle weighed, washed acid-free, in one and 6.5% NaOH and 0.15% sodium cyclohexyl

Dithiocarbamate is produced by sulfiding an alkali cellulose which has been aged to achieve the desired viscosity (40 to 60 poise) using 43% CS ₂ (based on air-dry cellulose) for 2 1/2 hours. The xanthate lumps are dissolved in sodium hydroxide solution, which contains the modifying agent in the amount necessary to achieve the desired concentration. After 3 hours of mixing at 17 ° C, the viscose is filtered in the cold state, deaerated and kept at 4 ° C until spinning, i.e. the spinning takes place like the high salt point (16.0), the high xanthate content (1.35% ) ^{and show} the low content of sodium trithiocarbonate (0.35%) in the unripened state. The stated alkali content of 6.5% relates in all examples to the total alkalinity expressed as NaOH; it includes both free NaOH and that bound in the form of sodium carbonate, sodium trithiocarbonate and sodium cellulose xanthate.

The viscose is pressed out of a spinneret (0.064 mm holes) into a primary precipitation and regeneration bath, which contains 9.5% H ₂ SO ₄ , 17% NA ₂ SO _{4 and} 10% ZnSO ₄ , a 720-thread 1 100- the thread bundle spun. The bath passage is 104 cm. The bath temperature is 62 ° C. and the speed of the first conveyor roller is 12.2 m / minutes. The threads are guided through a bath containing 2% acid at 98 ° C. by means of a second conveyor roller, which rotates at such a speed that a stretching of 100% takes place between the first and second conveyor roller. After stretching, the thread is kept at a constant length by wrapping the first conveyor roller several times or between the second and a third conveyor roller so that it maintains the length obtained during stretching at 1.3 to 2.5 m before it is subjected to relatively low tension is collected on a spool. The gel thread material is washed free of acid and salt and then processed further. It is finished in the moist state, rotated at 118 revolutions / m and tested after conditioning for 48 hours at 24 ° C. and a relative humidity of 56%. Some of the sized material is twisted into a 1100/2 cord. The cords are then tested after being conditioned in the same way as the threads.

Results (compared with unripened, unmodified viscose):

Table I (continued)

Gel swell ratio

(Movie)

Cord properties
Strength, g / den

conditioned

oven dry

Unripe,

not-

modified viscose

1.0

3.66 4.12

Unripe,

modified

viscose

0.52

4.07 4.57

Example 2

A viscose with a content of 5% cellulose from cotton lint and 6.5% caustic soda, which 0.25% sodium amyl dithiocarbamate is prepared in the manner described in Example 1 and using one containing 10.5% sulfuric acid, 17.0% sodium sulfate and 10% zinc sulfate Felling and regeneration bath spun. The threads are washed and sized. A part the same is twisted into a 1100/2 cord. The thread and cord properties are along with Comparative values for unmodified viscose are given in Table II. The strength and fatigue resistance of the cord from the goods obtained from the modified, unripened viscose are opposite the material spun from unripened, unmodified viscose under similar conditions

improved. _, " _DD

Table II Table 1

Bath acid,%

Thread properties
Strength, g / den

dry

wet

Loop strength

Strain, %

dry

wet

Loop stretch ..
Gel swelling (thread)

Unripe,

unmodified
viscose

Unripe,

modified

viscose

9.5

4.66
3.15 4.90
3.32 3.51 3.83 9.8
17.6
7.5 11.6
24.6
9.8 2.79 2.22

50

55

60

Bath acid,%

Thread properties
Strength, g / den

dry

wet

Loop strength ..

Strain, %

dry

wet

Loop stretch ..

Gel swelling (thread)
Cord properties

Strength, g / den

conditioned

oven dry

Fatigue, minutes

Unripe,

unmodified viscose

4.66 3.15 3.51

9.8 17.6 7.5 2.79

3.66 4.12 119

Unripe,

modified

viscose

10.5

4.63 2.55 3.67

12.3 21.6 10.2 2.31

4.13 4.42 545

Example 3

In the manner described in Example 1, a 0.16% sodium butyl nonoethanol dithiocarbamate modified viscose with a content of 5% cellulose from cotton lint and 6.5% sodium hydroxide solution produced and using an 8.5% sulfuric acid, 17.0% sodium sulfate and 10% zinc sulfate containing precipitation and regeneration bath spun. You wash the threads, size them and then twist them part of it into a 1100/2 cord. The filament and cord properties are in Table III compared with that of ordinary viscose. In the case of the modified, unripened viscose produced thread are the strength and the

Fatigue resistance of the cord compared to that of unripened, unmodified viscose in similar Conditions spun material greatly improved.

Example 5

Tabel III Unripe,
modified
viscose Unripe,
not-
modified
viscose 8.5
4.77
3.33
3.88
12.9
25.1
10.3
2.13
0.38
4.10
4.39
349 Bath acid, ° / o
Thread properties
Strength, g / den
dry
wet
Loop strength
Strain, %
dry
wet
Loop stretch
Gel swelling (thread) ...
Gel swell ratio
(Films)
Cord properties
Strength, g / den
conditioned
oven dry
Fatigue, minutes ... 8.2
4.66
3.15
3.51
9.8
17.6
7.5
2.79
1.0
3.66
4.12
119

3o example 4

The effectiveness of the dithiocarbamates in reducing gel swelling in films is shown in Table IV shown. Ten samples of a viscose are produced as described in Example 1. From these become Films poured. The precipitation bath contains 8.5% sulfuric acid, 17.0% sodium sulfate and 10.0% zinc sulfate.

Result:

Table IV

Modifying agents

none

0.58% sodium methyl dithio

carbamate

0.24% sodium benzyl dithio

carbamate

0.21% sodium-ethylene-bis-

(dithiocarbamate)

0.22% sodium-ljS-cyclohexyan-bis-

(dithiocarbamate)

0.46% sodium dibutyl dithio

carbamate

0.22% sodium dimethyl dithio

carbamate

0.27% sodium dioctyl dithio

carbamate

0.22% sodium lauryl dithiocarbamate 0.43% LitMum cyclohexyl dithiocarbamate

carbamate

0.60% sodium dithiocarbamate der

following mixture: 10% hexadecyl-10% octadecyl-35% octadecenyl-45% Octadecadienyl

gel
swelling
relationship
(Films) 40 1.00 45 0.81 0.51
0.61 50 0.30 0.49 55 0.57 0.76
0.94 60

0.81

0.84 A viscose containing 5% cellulose and 6.5% sodium hydroxide is mixed with 0.1% sodium cyclohexyl dithiocarbamate, 0.5% butoxyethanol and 0.2% polyethylene glycol (molecular weight 300) modified. The manufacture of the viscose, the spinning, the cleaning and sizing of the threads and the The thread and cord material are tested as in Example 1. The dry strength of the thread material is about 4.9 g / den and the strength of the cord is about 4.2 g / den compared to 4.6 and 3.6 g / den, respectively for unmodified material.

Except for the dithiocarbamates mentioned in the examples many others can be used, e.g. B. Hexamethylene - bis - dithiocarbamate, Potassium pentamethylene dithiocarbamate, sodium hexamethylene - bis - (isobutyldithiocarbamate), sodium ethylene bis (methyldithiocarbamate), Sodium 1,4-cyclohexane bis (ethyl dithiocarbamate) or sodium xylylene bis (dithiocarbamate).

Although most of the modifying agents have been used as the sodium salts, the invention is not limited to that. Any soluble salt of dithiocarbamic acid can be used; H. also lithium, potassium, ammonium or amine derivatives. The preferred modifying agents are the alkali salts of mono- or di-N-substituted dithiocarbamic acids that have no substituent contain more than 10 carbon atoms and in which the nitrogen is attached to an aliphatic carbon. From French patent specification 961 352 it is known, high-strength cellulose hydrate fibers from a To spin viscose, the monoamines, such as. B. triethanolamine, diethylamine, pyridine, piperidine, added have been. In contrast, the inventive method has the advantage that it is a better monitoring and more uniform control of the spinning process and thus more uniform production Products. The new process is also more economical and allows the reduction of unwanted thread breaks.

Claims (8)

PATENT CLAIMS: 1. A process for the production of structures from regenerated cellulose by pressing viscose containing a modifier into an acidic precipitation bath containing 1 to 15% zinc sulfate, characterized in that a soluble salt of an N-substituted dithiocarbamic acid is added to the viscose as a modifier. 2. The method according to claim 1, characterized in that the modifying agent to be used Salt of N-substituted dithiocarbamic acid on nitrogen is a hydrocarbon residue with a maximum of 18 carbon atoms. 3. Process according to claims 1 and 2, characterized in that as modifying agent Sodium cyclohexyl dithiocarbamate or sodium benzyl dithiocarbamate is used. 4. Process according to claims 1 to 3, characterized in that the salt of the N-substituted Dithiocarbamic acid is at least 0.05% soluble in 6% aqueous sodium hydroxide. 5. Process according to claims 1 to 4, characterized in that the acid bath also 9 10 4 to 12% sulfuric acid and 13 to 25% sodium 8. The method according to claims 1 to 7, thereby contains sulfate. characterized that the after pressing the 6. The method according to claim 5, characterized marked viscose structure obtained in the acid precipitation bath, that the acid bath is also stretched from 1 to 5% of the spinning by 20 to 100%. Contains iron (II) sulphate. 5 7. The method according to claims 1 to 6, there- considered publications:
characterized in that the amount of the German Patent No. 539 320;
Viscous modifier to be added between Swiss patent specification No. 204 208;
see 0.05 and 0.5%. French patent specification No. 961 352. © 109 617/421 6.61