DE1645275A1 - Process for the production of spinning solutions from acrylonitrile polymers or from copolymers with a high acrylonitrile content - Google Patents

Description

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Via Cernaia, 8 - Milan, Italy _L ^{CASE 021}

concerning

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Process for the production of spinning solutions from aoryl nitrile polymers or from mixed polymers with a high aoryl nitrile content,

The invention relates to a method for producing spinning solutions from polyacrylonitrile or from copolymers with a high acrylonitrile content, in particular with an aoryl nitrile content of more than $ 85. In particular, the invention relates to a process for the direct production of polymer · «b» w, misoh polymer solutions based on acrylonitrile in dimethylformamide under controlled temperature conditions, which spinning solutions have particular advantages, be it the molecular weight of the misoh polymer out "· sichtiiioh the quality of preserving union from them strands, be" Sonder in terms of their whiteness, have · the inventive method can widely used as an improvement and development of known methods such as that of the Italian Patent 501 67k, are considered "Xn this The patent specification claims the production of spinning solutions by dissolving the monomer in a solvent which is also suitable for dissolving the corresponding polymer and then carrying out the polymerization in the presence of a peroxide as a catalyst the acrylonitrile immediately directly polymerized in the solvent, which according to one of the examples of the patent was given as dimethylformamide *

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These known processes had advantages over other processes over those according to aqueous acrylonitrile dispersions or · * emulsions were used »

It is also known that "" can produce spun thread with a polyacrylonitrile content of more than 85 ^ 6, which have suitable textile and dye properties, which are obtained, for example, through the use of basic dyes * In these cases, however, one does not use acrylonitrile alone, but rather separate mixtures of well-defined ones Composition consisting of acrylonitrile and esters of the Acrylic and Metaoryla & ure and Vinylmonomerβ, the sulfone nuclei contain.

In order to better understand the requirements of the invention, reference is made to the content of example 3 of the aforementioned Italian patent 501 67%. The polymerization described in this example was carried out of the total monomers of the mixture with recovery of substantially 35 wt _# ^.

If one sets the conversion to in these known processes About $ 60 of the monomer continues, then you can use polymers obtained a molecular weight that is not entirely suitable for spinning and is less than 40,000. The final solutions of the polymer were also quite dark and resulted in filaments which did not have the most desirable properties of the white.

It is also known that in the polymerizations mentioned or mixed polymerizations, the reaction requires a certain “operating temperature, which is around 60 °”. The reaction Has a strong heat dissipation, so that the temperature of the real

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yawing mass tends to increase. This appearance According to it is difficult to control and limit the conversion of the monomer or monomers introduced into the reaction vessel and consequently the desired and for the spinning to obtain suitable molecular weight of the polymer? The course of the reaction is therefore not exactly repeatable under the predetermined conditions When manufacturing moscholymers, the sodium allyl sulfonate contain, then also have the spun threads obtained by the known method no exactly constant textile and dyeing properties, especially the content varies Sodium allyl filphonate, which is one of the most widely used Vinyl sulfonate monomer is to have the best coloring properties to achieve the FEden. This is due to the fact that Usually, technical grade sodium allyl sulfonate is used in powder form, which together with the other required ' Substances introduced into the reaction vessel, residues generated, which are insoluble in the copolymer solutions obtained. These solutions are cloudy and there are difficulties with Spinning, the spun threads obtained do not have constant proportions of sodium allyl sulfonate and the same textile and color properties. It is known that a proportion of sodium allylsulfonate which is less or greater than a well-defined, critical proportion range (which can be specified as $ 1.5-1.6) leads to difficulties and considerable Differences in the ability to fix the dyes. In particular, proportions lower than the critical ones lead Contributions to a completely inadequate coloration. It was found that the use of technical sodium allyl

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ORIGINAL INSPECTED

sulfonate in powder form, which as such in the to be copolymerized Mass is introduced, which also leads to fluctuations in the proportion of this salt in different samples can be more than 0.5? "while achieving a desirable production uniformity of spun threads with good and constant dyeing properties » It would be massive if these fluctuations were not greater than $ 0.1 or $ 0.2 or less.

According to the invention it was surprisingly found that " one can obtain polymers or copolymers whose average molecular weight is far greater than that of those previously available Polymer, i.e. on the order of 60,000-65,000, if you increase the monomer content in the mass at least up to 50-60 $ and the conversion process on the other hand, for values in the order of magnitude of 30- ^ 0 $ converted Polymer persists (i.e. in practice if one interrupts the process, if not more than 1/3 of the mass existing monomers were affected by the conversion). If the spinning solution consists of an acrylonitrile copolymer, which contains sodium allysulphonate, then one obtains vegetables a particular embodiment of the invention bright and homogeneous spinning solutions, from which one threads with constant Textile and dyeing properties. Ask these results known to be a considerable improvement in the quality of the generated threads.

A further considerable improvement in quality is achieved after, filaments are obtained from the polymers obtained by this premature interruption of the conversion; which not· the above-mentioned negative properties of a harmful

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chen coloring, but rather a considerable have a greater degree of ice "

A minimum of $ 50-60 is required to apply and realize the terms and conditions provided for in the present invention of the monomer or the monomers based on the total weight of the mixture to be polymerized in the reaction vessel bring in. If sodium allyl is used as the monomer. sulfonate is present, it is further preferable that the same to add the other monomers dissolved in dimethylformamide in the form of a clear solution in dimethylformamide A clear solution is obtained by dissolving the sodium allylsulfonate in dimethylformamide especially at about 50 ° in order to obtain a concentration of about 5-6 ^ i. This solution is then filtered and the filtrate is used as indicated above « The mixture prepared in this way of the monomer or monomers dissolved in dimethylformamide, which optionally contains additives, is heated to a temperature, in particular 60 ° C., at which the reaction can start »A preferred embodiment According to the invention, this temperature is achieved by the environment is kept under negative pressure, in particular under the residual pressure of 400 mm Hg, at w after reaching the temperature of 60 ° the mixture begins to boil. As soon these states are reached, the catalyst is heated in the Mass introduced and at the same time the heating is interrupted. According to the previously reached temperature the reaction immediately. However, the heat generated by the reaction cannot increase the temperature of the mass any further. since this WKrtae after a known phenomenon from the Transformation of the physical state of the constituents ν der Mass is absorbed, which® at the specified barometer

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printing takes place.

The application of this principle in the context of the invention is possible due to the determination of the pressure range in which the boiling point. _t the particular mixture used takes place, having its components boiling temperatures for the possibilities * Di 's components are condensed after evaporating outside the reaction vessel and returned in cooled state in the reaction vessel. Since the mixture contains low-boiling constituents, the proportions of these constituents evidently change as the reaction proceeds. However, it was found that the thermal fluctuations of the mass nioht larger than 5 ° C Siri, if the above is angegebenei.Druck maintained by 400 mm in the reaction vessel, then the entire reaction process at temperatures between 60 ° and 65 ⁰ C that takes place, ie under conditions in which the conversion takes place regularly with a certain temporal progression, so that the possibility remains to interrupt the polymerization process after a certain time after the start of the reaction and to obtain solutions in which a certain amount of monomer is converted. The implementation of the process according to the invention is explained in more detail using the following four typical examples.

EXAMPLE 1

Allow eleven in a glass reaction vessel with a Z 1 fit and k necks, which are provided with an anchor stirrer, thermometer, reflux condenser and nitrogen supply pipe and in which a thermostat is arranged

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1) 6θ5 g of dimethylformamide,

2) 3 # 25g sodium allyfceulfonate,

3) 590 g of distilled acrylonitrile,

k) 15 g of distilled methyl methacrylate

brought in"

Before these substances are introduced, the reaction vessel is washed with a stream of nitrogen which, even after the substances have been introduced and for the entire duration of the polymerization, is allowed to flow through continuously, but more slowly. The mass is stirred slowly bia reached a temperature of 58 ⁰ C.

Then the peroxide catalyst, in particular 2.8 g of lauryl peroxide, is introduced. This peroxide is preferably dissolved beforehand at 50 ° C. in 50 g of dimethylformamide, which, in the weighting of the contents given above, represents part of the 605 g of the dimethylformamide introduced at the beginning. A total of 1216 g of substances are thus introduced into the reaction vessel, of which the monomers make up 50%. This monomer could also be increased up to $ 60 by suitable dosing of the substances initially introduced. After 20 minutes, the internal temperature has risen to 61 ⁰ C, indicating the made Polymerisationseinsatz "After another 20 minutes, the temperature continued to rise to 62 ° C and the mass is completely opaque.

After a total of 4-sttindiger polymerization, during which the internal temperature is maintained by appropriate Einregelung stirring to 60-65 ⁰ C, the mass is doughy and viscous, and tends to block the RU ^ krwerk.

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This mass consists of approximately 155 ° polymers, 35 $ monomers and 50 $ dimethylformamide.

A further 550 g of cold dimethylformamide are now introduced, whereby the polymerization is interrupted and stirring is allowed to resume so that effective, regular stirring can be continued « After about an hour, all lumps are distributed and eliminated in the mass, which has been stirred with extreme strength, and a homogeneous liquid mass is obtained, which is easily distillable * * Its weight is 1766 g and it is made up of about $ 11.5 polymers ", from 22 5, $ monomers and from 66 $ dimethylformamide · the mass is in the vacuum distilled 6O ⁰ C to the non-polymerized © acrylonitrile and Methylmetaorylat to eliminate and rückzugewlnnen "After 2 stündlger distillation are completely eliminates these monomers and to obtain 125Og of an $ 16.5 mixed polymer solution.

This solution is clear and lemon yellow, i.e. much clearer than all those solutions obtained by the previously known methods. It is therefore suitable for the production of filaments with improved Veisse properties.

20 l of mixed polymer are obtained, which proves that the conversion the monomers were kept within limits of about $ 33 de. The average molecular weight of the polymer thus obtained is 65,000.

Filaments can be obtained from this polymer which have a satisfactory degree of optical texture. It goes without saying that the method according to the invention under Use of other means and apparatus can be realized if one only essentially adheres to the conditions set out above and in particular defined below, without doing so to leave the scope of the invention.

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From the above it follows without any further "how the improved process according to the invention allows to obtain a polymer which, thanks to its suitable average molecular weight and thanks to its degree of whiteness, has particularly favorable qualities for spinning and which can be produced in a relatively short time (in of the order of magnitude of k hours), which would not be possible with other known methods.

Moreover 1st * neichtlich, one that if would, however, work with lower temperatures and with lower monomer concentrations, would have to use methods that take much longer to obtain for the production of filaments suitable molecular weights. For example, if you work at temperatures in the order of magnitude of 45 «« 50 ^ο 0, the process would take about 48 hours »
EXAMPLE 2

Is provided in a glass reaction vessel with a 2 1 capacity and k necks "equipped with a anchor stirrer, thermometer, reflux condenser and nitrogen inlet tube, and which is arranged in a water thermostat at 65 ⁰ G, you two separated · compositions are sequentially introduced, and Swart

1) a mixture consisting of

454 g of distilled dimethylformamide, 590 g of distilled acrylonitrile »

15 g of distilled methyl methacrylate, 0.12g Thiohamatoffbioxyd,

2) 108 g of a 65% sodium malide sulfonate solution in dimethylformamide, which was prepared warm and filtered «

The mass is slowly de-throated and warmed, being inside

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of the reaction vessel until an internal temperature of 60 ° C. is reached, a vacuum of 360 mm Hg is generated. 2.8 g of lauryl peroxide, dissolved in 50 g of dimethylformamide at 60 ° C., are then introduced and the heating is interrupted. After 20 minutes, the internal temperature begins to rise by a few degrees, which indicates that the polymerization has taken place. The polymerization is carried out k hours under constant stirring, during which time does not increase the internal temperature of about 60-65 ⁰ C and the Beatandteile the boiling mixture are condensed and cooled in the Reaktionsgefäes · returned Then, 550 g of dimethylformamide are added and the mixture becomes a Stirred vigorously for an hour until a liquid, homogeneous and easily distillable dispersion is obtained, from which the non-polymerized monomers are removed by distillation in vacuo and the desired clear, light-colored mixed polymer solution is obtained, which can be spun immediately.

The resulting solution weighs 11 ^ 5 g and contains $ 17.96 of pesticides, corresponding to about 205 g of polymeric polymer.

It follows that 33 _t k $ of the introduced monomers were converted. The analysis of the polymer revealed the presence of 1.5/0 sodium allylsulfonate and this component was found to be essentially constant in a number of consecutive samples.

The average molecular weight of the polymer calculated according to known methods was 60,000 (the calculation was carried out in particular according to the method described in US Pat. No. 2 kok 713).

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To prove the uniformity of production, the corresponding quantity and analysis values of a different method * suches specified.

In this other experiment, repeated under the same conditions, 1i60 g of solution with 17% solids, corresponding to 197 g of mixed polymers! with a conversion of $ 32.2 obtain.

The mixed polymer analyzed contained 1.6 % sodium allyleulfonate, ie a proportion which lies within the specified critical limits in order to obtain the most favorable textile and dyeing properties. This latter solution when analyzed contained $ 23.53 and possessed nitrogen. a molecular weight of 61,000. EXAMPLE 3

Using the same modalities as in Example 2, the. Reaction vessel introduced one after the other two separate compositions of matter, and zwart

1) a mixture consisting of

k ^ k g distilled dimethylformamide, 590 S distilled acrylonitrile,

32 g ethyl acrylate, 0.12g thiourea dioxide.

2) 108g of a 6 $ solution of sodium allylsulfknat solution in dimethylformamide, prepared warm and filtered.

The polymerization is carried out in the same way as in Example 2, except that no vacuum is applied to the To keep the reaction temperature constant at the desired value.

The polymerization is continued for k hours with constant stirring so that the internal temperature does not

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Jq

rises above 6O-65 ° C.

Now 55O g of dimethylformamide are added and the mixture is stirred vigorously for one hour until a liquid, homogeneous and easily distillable dispersion is obtained the non-polymerizing monomers are removed by distillation in vacuo and 1i80g of a solution is obtained which contains 18 $ solids per equivalent to 212 g of mixed polymers, contains.

There was thus a conversion of $ 33.8 of the monomers introduced. The interpolymer contains 1.45 $ sodium allyle sulfonate and 23.7 $ nitrogen and its molecular weight is 62-300 x EXAMPLE 4

The procedure is as in Example 2, adding two separate compositions of matter one after the other to the reaction vessel be introduced, namely t

1) a mixture consisting of

454 g of distilled dimethylformamide, 590 g of distilled acrylonitrile,

32 g methyl acrylate, 0.12g thiourea dioxide.

2) 108 g of a 6% sodium allylsulfonate solution in dimethylformamide, prepared warm and filtered.

The polymerization is carried out as described in Example 2. After adding 550 g of dimethylformamide and distilling off the unpolymerized monomers, 1210 g are obtained a viscous solution containing $ 18.1 pesticides, equivalent to 219g Mixed polymers! contains.

The result is a conversion of $ 34.9 of the monomers introduced. The mixed polymer contains $ 1.5 sodium Allyl sulfonate and 23.6 $ nitrogen and its molecular weight is 64,300.

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Claims (1)

ft ■ PATENT CLAIMS 1) Ancestors for the preparation of spinning solutions from polymers or copolymers with a high polyacrylonitrile content, generally is higher than $ 85, through immediate preparation of the ί
Polymer or mixed polymer solution based on ο a mass · the acrylonitrile in dimethylformamide «. contains, preferably in combination with other monomers such as methyl methacrylate and sodium allylsulfonate, characterized in that the polymerisation process of a mass which contains a relatively large amount of monomers)! started under controlled temperature conditions and is only interrupted after the conversion of part of the monomer (s), so that a spinning solution suitable for the formation of improved spun filaments in terms of their molecular weight and properties is obtained. 2) Method according to claim 1, characterized in that the polymerization is interrupted when about 1/3 of the of the monomers is converted, 3) Process according to claims 1 and 2, characterized in that a mass of polymerization is subjected to the 50-60 $ of the monomer (s) and that the polymerization is interrupted when 30-40 ^> of or "the existing monomers have been converted" k) Process according to one or more of the preceding claims, characterized in that the polymerization is carried out at temperatures in the order of magnitude of 60-65 ° C « «13- 009811/1614 5) Method according to one or more of the preceding claims, wherein the starting material contains acrylonitrile »methyl methacrylate and sodium allylsulfonate, characterized in that the sodium allylsulfonate is added to the other constituents of the reacting composition in the form of a clear solution in dimethylformamide. ₌ 6) Method according to claim 5 »characterized in that the clear sodium allylsulfonate solution in dimethylformamide Possesses concentration of $ 4-6. 7) Method according to one or more of the preceding claims, characterized in that the temperature control is carried out by means of a negative pressure in the reaction space, while the reacting mass on the polymerization temperature door is brought at which the mass begins to boil and that the reaction takes place at a substantially constant temperature and at the same barometric pressure, according to the absorption of heat energy, the reaction proceeds to transform the Mixing in steam, so that the reaction and in particular the progress of the conversion of the monomer (s) is kept under control, 8) The method according to claim 7, characterized in that the reaction is carried out in a room-p. in that one There is residual pressure of 400 mm Hg. 9) Method according to one or more of the preceding claims, characterized in that jbu Bieginn of the polymerization with a monomer solution in a relatively ge Dimethylformamide wrestling amount / is being worked and that another dimethyl formamide addition is carried out when the bulk of the products Reached density values that hinder stirring, so that the _if 009811/1614 •• 14— Polymerization is interrupted and the mass is returned to a homogeneously liquid state in order to to be able to easily distill off unreacted monomers 10) Method according to claim 9, characterized in that the solvent added at the end of the polymerization is at room temperature 11) Method according to one or more of the preceding Claims, characterized in that the unconverted monomers are recovered in a distillate in which they are in dimethylformamide, ■ 12) Spinning solution, which according to the method according to one or several of the preceding claims was produced, characterized in that the polymer in the spinning solution Has a molecular weight of the order of 65 * 000 13) spinning solution according to claim 12, characterized in that it is clear and lemon-yellow and is suitable for the production of spun thread with good white properties. -15- 009811/1614