DE1469025C - Process for the production of acrylonitrile polymer fibers - Google Patents

Description

1 .2

The invention concerns a method for Her- Expediently used in the invention

make threads and fibers from an acrylonitrile process according to an acrylonitrile polymer

polymer according to the nitric acid process. with an average molecular weight of 60,000

Dissolving polymeric acrylonitrile in HNO ₈ to 100,000.

and the spinning at low temperatures is 5 The good handle, which is an essential characteristic of the well-known. In the German Auslegeschrift 1030 969 fibers produced according to the invention, a process for the production of acrylonitrile is described, although polymer fibers are not exactly based on numerical comparisons, but demonstrates from a solution that the fibers of undegraded polymer produced according to the invention fall in aqueous nitric acid by the pleasant feeling, acidic of 54 to 65% and spinning same in io that they prepare on the skin. This runs out of considerable aqueous nitric acid. This method is the difference in the handle and "feel" between the primarily characterized in that the nitric products obtained according to the invention and the previously acidic polymer solution in a precipitation bath of well-known means an essential technical thin nitric acid with an HNO ₃ content of progress .

44 to 46% is spun and the take-off 15 um according to the invention with synthetic acrylic fibers speed is greater than the theoretical Aus a good grip, in particular. a pleasant one to get the speed of the polymer solution from the feeling when worn on the skin, must Spinneret. the production under very specific, so far not the object of the invention is the production of the proposed conditions. Self-made acrylonitrile polymer fibers, who have a good grip ao of course stand all conditions such as molecular and feel especially good when they are weight of the polymer, temperature and concentration directly come into contact with the skin. It tration of the solvent, the spinning and __ · it has been found that this goal can be achieved, drying conditions, in mutual dependence the molecular weight of the crude polymer.

its concentration in the dope or 35 The use of at least 66 ° / _o by weight Sal viscosity of the spun polymer solution, peter acid as the solvent, which contains no more than the solvent, the spinning conditions and 0.0005% nitrous acid, is mainly the Very specific drying conditions are required because the acrylonitrile polymer is limited in the way. Dissolved state in the spinning solution by the Kon-The subject of the invention is a method for the centering of the nitric acid used. Manufacture of threads and fibers by spinning flows and because the state of the solution has a considerable influence on the structure due to the dissolution of an acrylonitrile polymer of the gel formed in strong aqueous nitric acid at low temperature and on the physical properties of the highly viscous spinning solution produced, which has up to the finished fibers. If the concentration of the spinning nitric acid is kept at a low temperature and is below 66%, according to the invention, no satisfactory results are achieved in a precipitation bath of cold, diluted nitric acid.
acid, the HNO ₃ content of which is lower than that of When using a more than 66% nitric spinning solution, further coagulation of the acid obtained as a solvent, well-precipitated fibers can be produced by treating with even stronger threads or fibers, which at 100 ⁰ C, dilute aqueous nitric acid, washing the 40 This is a very important discovery both threads or fibers with water, drawing in from the standpoint of technical implementation as hot water and drying, which also with regard to the properties of the obtained is characterized by the fact that one .. fibers. It is for the method of the invention

It is essential to use appropriate concentrations of nitric acid

a) a spinning solution is used that select 45 by dissolving, in which the precipitated fibers can easily be ^{stretched in an at least 85% * us} acrylonitrile built up of the heat. The spinning solution produced in this way at a temperature below the polymer must also have a viscosity of 5 ^° C. in nitric acid of more than 66%. those of 700 poise or above at ⁰ ° C; with a content of nitrous acid is less than 0.0005% spinning solution, which has been prepared with a polymer from Molebeträgt, and their vis- 50 kulargewicht prepared 60000-100000 viscosity by at least 700 poise (measured at 0 ⁰ C), be Achieved particularly favorable results is, The molecular weight is determined on

b) the temperature of the spinning solution from preparation best by the light scattering; and an acrylic acid bis keeps below 5 ° C for spinning, nitrile polymer with a useful molecular

c) an aqueous precipitation bath of 5 ° C or below 55 weight, which uses at least 85% acrylonitrile, which contains 28 to 36% nitric acid, has an intrinsic viscosity of 115 to 170 ccm / g holds, and the resulting threads in the precipitation bath at 35 ° C in dimethylformamide. It doesn't hurt can shrink by at least 15% if the nitric acid used as a solvent

d) for the subsequent treatment of the threads, a certain amount of other components in such 15 to 25% strength aqueous nitric acid used, contains 60 degrees that it the state of the polymer whose temperature does not significantly affect the solution above room temperature. the temperature is the most essential condition for the achievement of the inven-

e) stretching the previously is acid free with water dung achievable according advantages in that the washed filaments in hot water at 100 ⁰ C - although a derartigs.hochkonzentrierte nitric or undertakes including while acid at 65 is used as a solvent - not to 7-Hf After stretching, denaturation of the acrylonitrile polymer in the

f) the final drying takes place with a Tempe solution. When the conventional organic performs temperature above 8O ⁰ C. Solvent in the manufacture of synthetic

3 4

Acrylic acid nitrile fibers are used, acid nitrile fibers are not suitable. To achieve the benefits chemical reaction between the polymer of the process according to the invention, it is also necessary

and the solvent to be feared, so that the agile that in the above-described white

chemical properties of the fibers obtained in this way, the spinning solution produced is pressed into a precipitation bath

are only dependent on the starting polymer. 5, which is a 28-36% ³ aqueous nitric acid

On the other hand, when is a concentrated nitric acid and is kept below 5 ° C. The Koagu-

is used as a solvent, one must always lation conditions and the state of the polymer

even with an implementation option between the sats in the spinning solution, the essential facts are

Acrylic acid nitrile polymer and nitric acid, which form the fine gel structure of the precipitated fiber

calculate. If, as mentioned above, influence a highly concentrated io. If z. B. the temperature of the

trated nitric acid of more than 66% used baths above 5 ° C or if the concentration chests

is to the claimed according to the invention of the nitric acid in the precipitation bath outside of the

Achieving benefits takes place at this concentration specified limits, d. H. less than 28%

unavoidable a chemical conversion of moles or more than 36%, the inventions are

Cooling of the acrylonitrile polymer with nitric 15 according to the asserted advantages not achieved. the

acid instead. In the description of the United States patent, the next essential step is the precipitated fiber

font 2 928 715 z. B. it is stated that a 15 to 25% aqueous nitric acid

Nitration of the polymer takes place, if one more and then through water to lead to the acid

used as 65% nitric acid. The we- wash out. Although not the second felling bath

The nitriding effect on the properties of the fiber 20 needs to be kept below 5 ° C

However, one has to be insignificant in comparison z. B. not at a temperature above room temperature

for hydrolysis of the nitrile groups of the polymer only achieved no advantage, but the advantages of

chain, crosslinking and polymer degradation process according to the invention are also lost,

recognized. According to the invention, however, the following invention, it is necessary to put the fibers in

found: The nitration of the acrylonitrile poly- 25 in the first precipitation bath during coagulation

Merisats in more than 66% nitric acid will shrink 15 to 50%. In the second coagu-

but with extremely small amounts of nitrous lation it is not necessary that the fiber

Acid (nitrogen dioxide) speeds up, but is used for shrinking. ■

a certain time is required for technical processing. The fiber precipitated in this way is after washing

tion is sufficient, e.g. B. about 200 hours, completely 30 with water to remove the acid in hot

prevented when the content of nitrous acid is water at 100 ° C or below in a known manner

to less than 0.0005%, preferably less than stretched, so that at least 7-fold stretching

0.0003%, is reduced. To get the feared kung. But if the general agreement

To completely prevent implementation, it is necessary- the aspect ratio is greater than 1:11, the

agile, the temperature at the dissolution, the 35 advantages according to the invention turned into the opposite.

Storage and transport of the spinning solution under- In this case a small amount of inorganic

Half 5 ° C, preferably below 3 ° C, to keep, also nischen salt, organic compound, inorganic

when the nitrous acid has already been removed. To or organic acid to the water in such quantity

a nitric acid with a content less that the drawing power can be added

than 0.0005% nitrous acid as a solvent for 40 is not affected. The application of a con-

Being able to use acrylonitrile polymers, however, is centered inorganic salt solution as a bath

The acid must also be stored very carefully, which is very inexpedient. After the hot stretching,

will. It can e.g. B. be necessary to always dry the moist fiber with air, which is at least

Contains urea in the nitric acid, from which it has ^{been heated to 8O 0} C in order to

the nitrous acid has already been removed to obtain proper benefits. When the fiber at

and the acid is dried to less than 80 ° C at a low temperature, the inven-

to preserve. The pipeline to the advantages achievable according to the invention also lost. If at

dissolving device must be cooled. Normal pressure is dried, the temperature rises

Furthermore, the quality of the nitric acid itself, of the fiber itself, does not have to exceed 100 ^° C., so it is sufficient

carefully checked before use. There 5 ° hot air with a temperature below 150 ⁰ C

gives z. B. nitric acid, from which nitrous acid is made. Appropriate heat treatment of the fiber

Acid due to other impurities it contains - after drying does not affect the inven-

can hardly be removed. In the context of the properties obtained according to the instructions,

lying method was repeatedly found to carry out the inventive method

that such nitric acid quickly becomes nitrous again, the acrylonitrile polymer or

Acid. Forms by decomposition of nitric acid, -mischpolymerisat produced in a known manner,

even if the nitrous acid is completely

was disheartened. Of course, nitric acid is suitable; breastfeeding is carried out using a monomer mixture,

from which the nitrous acid can easily be removed, at least 85 percent by weight of acrylic

can, better for the use according to the invention. 60 is acid nitrile. When the amount of acrylic acid

The quality of the nitric acid can be quickly reduced to less than approximately the nitrile in the monomer mixture

Check the following way: 500 ecm of nitric acid will be 85 percent by weight, you can take advantage of the

which is placed in a flask, and it is not fully achieved by the method according to the invention

a fine glass tube of air blown in at 50 ° C. If, even if the copolymer according to the invention

the content of nitrogen dioxide in the nitric acid 65 is treated according to. Examples of monomers that

within an hour to 0.01% ° of the below that polymerized with acrylonitrile to form copolymers

drops, the nitric acid is excellent as can be dissolved, are compounds with the

solvent for the production of synthetic acrylic- simple radical CH ₂ = CH -. So z. B.

Claims (1)

5 6 Vinyl esters, especially vinyl esters of saturated pressed and precipitated. During the precipitation, aliphatic monocarboxylic acids such as vinyl acetate shrunk the fiber by 18%. Then the vinyl propionate, vinyl butyrate and the like, acrylic acid and fiber were transferred to a second precipitation bath, which was made up of α-substituted acrylic acid (e.g. methacrylic acid and a 20% aqueous nitric acid solution of ethacrylic acid); Esters and amides of these acids consisted of 5 15 ° C, and washed with water. In the (z. B. methyl acrylate, ethyl acrylate, propyl acrylate, Bu-second precipitation bath and in the water bath) every ethyl acrylate, methyl methacrylate, ethyl methacrylate, pro roll was adjusted so that the fibers did not shrink precipitated fiber was dissolved in hot methacrylamides N - Methylacrylsäureamid, water of 90 ⁰ C (the pH of the water was N - Äthylacrylsäureamid, N - Propylacrylsäureamid, io reacted with phosphoric acid to 3) to 9 times N - Butylacrylsäureamid, N - Methylmethacrylsäure- their Stretched length, and the obtained swollen amide, N-ethyl methacrylic acid amide, N-propyl meth fiber was dried in hot air of 130 ° C, acrylic acid amide and N-butyl methacrylic acid amide The obtained fiber had an extraordinary and the like); Methacrylic acid nitrile, ethacrylic acid nitrile and good grip. A fiber made under the same conditions, but with 65% nitric acid and other various vinyl and acrylic acid solvents, did not feel as good to the joints that interpolymerized with. Acrylonitrile a thermoplastic polymer Example 2 result, can be used. Alkyl esters of x- or / J-unsaturated polycarboxylic acids and, in addition, a binary copolymer of 93% acrylic Vinyl compounds, the sulfonic acid residues deacitrile and 7% methyl acrylate with the middle hold, can with acrylonitrile to the invention Molecular weight 77,000 was in Example 1 according to usable copolymers polymer- used nitric acid at 0 ° C to form a spinning will. solution with a viscosity of 800 poise at 0 ° C For the production of copolymers for 25 solved. The spinning solution was kept between 0 and -5 ° C. The process according to the invention can be kept customary until it reached the nozzle, and then precipitated into a 32% aqueous nitric acid for catalysts, such as ammonium or alkali persul, perboric acid and percarbonic acid, hydrogen pressed, where it was shrunk by 15%, peroxide, benzoyl peroxide, substituted benzoyl peroxide The fiber was then passed into a 15% aqueous salt oxide with one or more substituents in pitric acid, washed with water, in a hot benzene nucleus, Lauroyl peroxide, lauroylbenzoyl peroxide, water of 100 ⁰ C to 8 times their length vertert.-Butyl peroxide, cumene hydroperoxide and azo stretches and ^{dried in hot air of 100 0} C, compounds such as 2,2'-azobisisobutyric acid nitrile, the fiber obtained had one to be turned extraordinarily. Good grip to promote polymerization. A fiber under the same Bekönnen mercaptans such as lauryl mercaptan, / 3-mer 35 conditions, but, etc. at 70 ° / ₀ nitric acid with captoäthanol, thioglycolic acid., And others 0.03% content of nitrous acid produced appropriate dispersants should be used. For not had such a good grip as the above-mentioned polymerisation can use water as a solvent, fiber,
or suitable organic solvents used Example 3 will. Of course, the 40 achieved according to the invention are Advantages are not only limited to polymers that A ternary copolymer made of 92% acrylic produced by this polymerization process are acid nitrile, 7% methyl methacrylate and 1% sodium earth. It is also possible to use polymers with metheballylsulphonate having an average molecular weight. B. weight 90,000 was dissolved in 68% nitric acid with hydroxynitrilosulfonic acids or salts thereof 45 O ⁰ C to the spinning solution. This solution had or inorganic compounds with tetravalent a viscosity of 1300 poise at O ⁰ C. The SaI sulfur have been obtained. The following nitric acid was cleaned thoroughly beforehand until the games explain the process according to the invention. Nitrous acid content was 0.0002%. To all operations were carried out at 2 ° C. Example _{50 before dissolving.} The spinning solution was through a A spinning solution was prepared by pressing a nozzle with openings 0.08 mm in diameter into acrylonitrile polymer made from 90% acrylic acid-33% nitric acid at -5 ° C. for precipitation from nitrile, 5% methyl acrylate and 5% vinyl acetate, with the fibers around 20% contracted the mean molecular weight 85,000 in 70%. Then the fiber was dissolved in 19% nitric acid. The solvent, the 55 acid led at 15 ° C, washed with water to 70% nitric acid, was previously removed by addition of the acid as far as possible, to that of hydrogen peroxide and urea, up to 4 times their length in water of 70 ° C and on which nitrous acid content reached 0.0004%. 2-fold stretched in water of 100 ⁰ C and the polymer was dried in the hot air of nitric acid at 150 ° C. The obtained 3 ⁰ C dissolved, and when transferring the solution 60 fiber had an extraordinarily good handle; but if in the spinning device, the degassing and others it was only in the first bath up to 4 times or measures the solution was kept below 5 ° C but the second time it was 3 times stretched. The polymer was in the solution was, it did not have such a good grip,
medium to a viscosity of 1100 poise at 0 ° C solved. This spinning solution was through a nozzle 65 'claim: with 2000 openings, the diameter of which is 0.1 mm. Process for making threads and in a 30% acid aqueous solution for fibers by spinning one by dissolving 3 ° C at a rate of 7 m per minute of an acrylonitrile polymer in a strong aqueous Highly viscous spinning solution produced at low temperature from nitric acid, which is kept at a low temperature until spinning, in a precipitation bath of cold dilute nitric acid, the HNO ₃ content of which is lower than that of the spinning solution, further coagulation of the threads or fibers obtained by treating with even more dilute aqueous nitric acid, washing the threads or fibers with water, drawing in hot water and drying, characterized in that one a) a spinning solution used, the built-up by dissolving an at least 85% of acrylonitrile polymer at a temperature below 5 ⁰ C in nitric acid of more than 66 ⁰ I _0, the content of nitrous acid is less than 0.0005 ° / ₀ produced has been and whose viscosity is at least 700 poise _ "(measured at 0 ⁰ C), b) the temperature of the spinning solution from manufacture to spinning ^{keeps below 5 0} C, c) an aqueous precipitation bath at 5 ° C or below used, which contains 28 to 36% nitric acid, and the resulting threads in the precipitation bath shrink by at least 15% leaves, d) 15 to 25% nitric acid is used for the subsequent treatment of the threads, whose temperature is not above room temperature, e) stretching the previously hot with water until acid-free washed Fäden'in water at 100 ⁰ C or below and thereby makes the 7- stretched to llfache, f) performs the final drying at a temperature above 8O ⁰ C. 009 510/178