TW201946942A - Process for preparing carbodiimides - Google Patents

Abstract

The present invention relates to a process for preparing polycarbodiimides, comprising (i) preparing a reaction mixture comprising a diisocyanate and a catalyst, and (ii) polymerizing the diisocyanate to give the polycarbodiimide in a stirred tank by heating the reaction mixture prepared in (i) to a temperature in the range from 20 to 250 DEG C at a pressure in the range from 20 to 800 mbar, with stirring of the reaction mixture during the polymerizing with a stirrer apparatus, which comprises axial conveying of the reaction mixture axially to the axis of rotation of the stirring operation by virtue of the stirring operation.

Description

Method for preparing carbodiimide

The present invention relates to a method for preparing a polycarbodiimide and a polycarbodiimide composition obtainable by or based on the method of the present invention.

Polycarbodiimides are known, for example, as oligomers and polymers used as stabilizers to avoid hydrolysis in plastics. These oligomers and polymers are prepared by polymerizing a diisocyanate using a decarboxylation reaction in which two isocyanate groups are reacted in each case to generate a bridged carbodiimide unit that removes CO ₂ . Further polymerization ultimately results in an oligomer or polymer with multiple carbodiimide groups and terminal isocyanate groups of the following formula:
O = C = N- [RN = C = N] _n -RN = C = O
Where n is typically in the range of 1 to 30.

The polymerization reaction is typically performed using a catalyst. The catalyst used may be an organic phosphorus compound. These catalysts are highly active and allow rapid condensation reactions under fairly mild conditions.

For example, US 4419294 relates to a method for preparing polycarbodiimide from 1,3-bis (1-methyl-1-isocyanateethyl) benzene (TMXDI). In the preparation, TMXDI is mixed with a suitable catalyst and degassed by passing nitrogen therethrough. The condensation is performed under an inert gas atmosphere at a standard pressure. This example produced an oligomeric carbodiimide having a content of 22.4% by weight of NCO groups after 23 h at 150 ° C. The disadvantage here is that despite the relatively long reaction times, only relatively small conversions are achieved.

DE 4 318 979 A1 likewise describes the preparation of carbodiimide based on TMXDI. Here, the reaction at 180 ° C. for 22 hours produced NCO in an amount of about 5 wt%. Although the conversion rate is slightly higher than US 4419294, the product obtained is relatively dark due to the higher reaction temperature, limiting its availability.

Despite the known prior art methods, there is still a need for a faster and more economical method for polymerizing carbodiimide.

WO 2014/044743 A discloses that the introduction of an inert gas into the reaction mixture during the polymerization can significantly accelerate the production of carbodiimide. However, the disadvantage of this method is that the inert gas is a significant load on the exhaust system of the reactor, and therefore unless special precautions are taken, isocyanates are released into the environment.

On the other hand, US 2010/124147 A1 relates to a mixer impeller with high-efficiency blades. Ian Torotwa et al. In Designs, Bd. 2, Nr. 10, 8. Marz 2018 (2018-03-08), Seiten 1-16 involve the study of the mixing efficiency of different impeller designs.

The problem solved is therefore to provide an improved method for preparing polycarbodiimide. The specific problem solved is to provide a method for preparing a polycarbodiimide that is more economically feasible than the known prior art methods, especially for reaction time and / or for the equipment required for this purpose. Another problem addressed is, in particular, to provide a method for preparing a polycarbodiimide having a lower degree of environmental pollution than known methods. Therefore, it was unexpectedly found that the use of a stirrer for mixing the reaction mixture during polymerization imparts an axial movement component to the agitated material such that the agitated material is conveyed toward or away from the substrate of the agitation tank, This can significantly reduce the time required to obtain the desired degree of polymerization. Furthermore, it has been unexpectedly found that the additional introduction of an inert gas can further shorten the time required to obtain the desired degree of polymerization.

The method of the present invention for preparing a polycarbodiimide comprises: in (i) preparing a reaction mixture comprising a diisocyanate and a catalyst; and in (ii) by a pressure in the range of 20 to 800 mbar The diisocyanate is polymerized by heating the reaction mixture prepared in (i) to a temperature in the range of 20 to 250 ° C to form the polycarbodiimide, wherein the reaction mixture is stirred with a stirrer device during the polymerization The method has the characteristic feature that the stirring operation transfers the reaction mixture axially to the rotation axis of the stirring operation.

In the foregoing specific examples, there is no limitation on the number of method steps such as (i) and (ii). Correspondingly, in other specific examples, the method may include other method steps.

In addition, it is possible to perform one or more of the defined method steps iteratively; for example, it is possible to perform steps (iii), (iv), or (v) repeatedly in that sequence before step (vi). The preferred sequence of method steps is (i), (ii), as in the sequence defined in Specific Example 1 below, and these steps are better followed by method steps (iii), (iv) and (v) , As in the sequence defined in specific example 51 below, only in that sequence, and more preferably followed by (vi), as defined in specific example 58 below.

There are no restrictions on the conditions, especially the temperature to be reached, the pressure to be applied, and the overall duration of heating or the duration of heating at the temperature to which the reaction mixture is heated in (ii), provided that the method is In (ii), the reaction mixture prepared in (i) can be heated in a stirred tank to a temperature in a range of 20 to 250 ° C. under a pressure in a range of 20 to 800 mbar. Polymerization of diisocyanate is performed to obtain polycarbodiimide.

Relative to the conditions under which the reaction mixture is heated in (ii), preferably, in (ii), the reaction mixture is heated to 40 to 230 ° C, more preferably 60 to 210 ° C, more preferably 80 to 200. ℃, more preferably 100 to 190 ° C, more preferably 120 to 180 ° C, more preferably 130 to 170 ° C, more preferably 145 to 155 ° C, and particularly preferably a temperature to be reached in the range of 140 to 160 ° C.

Relative to the conditions under which the reaction mixture is heated in (ii), it is further preferred that, in (ii), it is 50 to 750 mbar, preferably 100 to 600 mbar, more preferably 150 to 500 mbar, The reaction mixture is heated at a pressure in the range of more preferably 200 to 400 mbar, more preferably 250 to 350 mbar, more preferably 270 to 330 mbar, and more preferably 290 to 310 mbar.

Compared to the conditions under which the reaction mixture is heated in (ii), it is further preferred that in (ii), the reaction mixture is heated at a temperature to be reached for 6 to 96 hours, preferably 8 to 72 Hours, more preferably 10 to 48 hours, more preferably 12 to 36 hours, more preferably 14 to 30 hours, more preferably 16 to 24 hours, and particularly preferably 18 to 22 hours.

More specifically, preferably, in (ii), the reaction mixture is heated to 40 to 230 ° C, more preferably 60 to 210 ° C, more preferably 80 to 200 ° C, and more preferably 100 to relative to these conditions. A temperature in the range of 190 ° C, more preferably 120 to 180 ° C, more preferably 130 to 170 ° C, more preferably 145 to 155 ° C, and particularly preferably 140 to 160 ° C, and in (ii), 50 to 750 mbar , Preferably 100 to 600 mbar, more preferably 150 to 500 mbar, more preferably 200 to 400 mbar, more preferably 250 to 350 mbar, more preferably 270 to 330 mbar and more preferably 290 to 310 mbar The reaction mixture is heated under an internal pressure, and in (ii), the reaction mixture is preferably heated at a temperature to be reached for 6 to 96 hours, preferably 8 to 72 hours, more preferably 10 to 48 hours, more preferably A period of 12 to 36 hours, more preferably 14 to 30 hours, more preferably 16 to 24 hours, and particularly preferably 18 to 22 hours. More preferably, in (ii), the reaction mixture is heated to 140 at a pressure of 290 to 310 mbar for a duration of 18 to 22 hours, preferably at a temperature of 140 to 160 ° C to be reached. Temperatures up to 160 ° C.

There are no restrictions on the agitator equipment in (ii), provided that the reaction mixture can be transferred axially to the axis of rotation of the agitation operation by means of the agitation operation. Preferably, the agitator device in (ii) is composed of one or more axial transfer agitators, more preferably from 1 to 4, more preferably from 1 to 3, more preferably from 1 or 2 axial Conveying agitator consisting of one of the (ii) axial conveying agitators. Typically, the agitator device or each individual agitator of the agitator or a plurality of agitators has a rotation axis.

Regarding the stirring operation itself, it is well known that the stirrer device in the entire container (here, the stirring tank) causes a transfer volume flow rate and a circulation volume flow rate in particular. For circulating volume flow, a circulation coefficient dependency is typically assumed, the latter being expressed as _kz . The cycle factor depends on the type and geometry of the agitator. For example, a detailed description of circulation volume flow and circulation coefficient can be found in "Mischen und Ruhren: Grundlagen und moderne Verfahren" [Mixing and Stirring: Basics and Modern Methods], editor: M. Kraume, Wiley-VCH 2003. More specifically, the term "circulation coefficient" and the corresponding parameter k _z as used in this application are preferably the same as "Mischen und Ruhren: Grundlagen und moderne Verfahren", editor: M. Kraume, Wiley-VCH 2003 ( In particular, on page 31, those stated in section 2.3) have the same meaning.

For cyclic coefficient k _z no limitation, conditional transfer for the agitator consists of an axial agitator device. If the agitator device is composed of an axial conveying agitator, preferably the agitator has a range of 0.05 to 5, more preferably 0.1 to 4, more preferably 0.3 to 3, more preferably 0.5 to 2.5, more preferably 0.6 to 2, The cycle coefficient k _{z in the} range of more preferably 0.7 to 1.5, more preferably 0.8 to 1.3, and more preferably 0.9 to 1.1.

There is no limit to the geometrical relationship of the agitator equipment, more specifically, provided that it consists of an axially conveyed agitator to the agitating tank. If the agitator device is composed of an axial conveying agitator, preferably, the ratio of the diameter of the agitator to the inner diameter of the agitation tank is 0.05 to 0.85, more preferably 0.1 to 0.8, more preferably 0.2 to 0.75, and more preferably 0.3 to 0.7, more preferably 0.35 to 0.65, more preferably 0.4 to 0.6, and particularly preferably 0.45 to 0.55.

According to the aforementioned alternative, it is particularly preferred that the agitator device consists of an axial conveying agitator, and that the agitator has a range of Better 0.6 to 2, better 0.7 to 1.5, better 0.8 to 1.3, and better 0.9 to 1.1 cycle coefficients k _z in which the ratio of the diameter of the stirrer to the inner diameter of the stirring tank is 0.05 to 0.85, more preferably 0.1 to 0.8, more preferably 0.2 to 0.75, more preferably 0.3 to 0.7, more preferably 0.35 to 0.65, more preferably 0.4 to 0.6 and particularly preferably 0.45 to 0.55. Therefore, it is particularly preferable that the stirrer device is composed of a stirrer, and the stirrer has a circulation coefficient k _{z in a} range of 0.9 to 1.1, wherein the ratio of the diameter of the stirrer to the inner diameter of the stirring tank is 0.45 to Within 0.55.

Likewise, there is no limitation on the circulation coefficient k _z , provided that the agitator device is composed of a plurality of axially conveying agitators. If the agitator device is composed of a plurality of axial transfer agitators, preferably, the a plurality of agitators have a range of preferably 0.05 to 5, more preferably 0.1 to 4, more preferably 0.3 to 3, more preferably 0.5 to 2.5, The average cycle coefficient k _{z in the} range of more preferably 0.6 to 2, more preferably 0.7 to 1.5, more preferably 0.8 to 1.3, and more preferably 0.9 to 1.1.

There is no limitation on the geometric relationship of the agitator equipment, more specifically, provided that it is composed of a plurality of axially conveyed agitators to the agitating tank. If the agitator device is composed of a plurality of axial transfer agitators, preferably, the ratio of the average diameter of the agitators to the inner diameter of the agitating tank is 0.05 to 0.85, preferably 0.1 to 0.8, and more preferably 0.2 to 0.75, more preferably 0.3 to 0.7, more preferably 0.35 to 0.65, more preferably 0.4 to 0.6 and more preferably 0.45 to 0.55.

According to the aforementioned alternative, it is particularly preferred that the plurality of agitators have a range of preferably 0.05 to 5, more preferably 0.1 to 4, more preferably 0.3 to 3, more preferably 0.5 to 2.5, more preferably 0.6 to 2, more preferably 0.7 to 1.5, more preferably 0.8 to 1.3 and more preferably 0.9 to 1.1 average cycle coefficient k _z , wherein the ratio of the average diameter of the multiple stirrers to the internal diameter of the stirring tank is 0.05 to 0.85, preferably 0.1 to 0.8, more It is preferably in the range of 0.2 to 0.75, more preferably 0.3 to 0.7, more preferably 0.35 to 0.65, more preferably 0.4 to 0.6 and more preferably 0.45 to 0.55. Thus, in particular, preferably, the agitator stirrer device transmits a plurality of axially composition, and preferably the agitator having an average cyclic coefficient k _z in the range from 0.9 to 1.1, wherein the plurality of average agitator stirrer The ratio of the diameter to the inner diameter of the stirring tank is in the range of 0.45 to 0.55.

If the stirrer device consists of one or more axially conveyed stirrers, there is no restriction on the size of the one or more stirrers, especially the diameter, provided that the reaction mixture can be axially adjusted by means of a stirring operation. Transfer to the axis of rotation of the stirring operation. As for the diameter of one or more agitators, preferably, the diameter of one agitator or the average diameter of a plurality of agitators is 10 to 500 cm, preferably 30 to 300 cm, more preferably 50 to 200 cm, and more preferably 70 To 150 cm, more preferably 80 to 120 cm and more preferably 90 to 110 cm.

If the agitator device is composed of one or more axial conveying agitators, there is no restriction on the size of the agitation tank, especially the inner diameter of the agitation tank. As for the inner diameter of the stirring tank, it is preferably 20 to 5000 cm, preferably 40 to 3000 cm, more preferably 60 to 2000 cm, more preferably 80 to 1500 cm, more preferably 100 to 1000 cm, and more preferably 120 to 500 cm, more preferably 140 to 300 cm, more preferably 160 to 250 cm and more preferably 180 to 220 cm.

There are no restrictions on the properties of the reaction mixture, especially its fluid volume, provided that the reaction mixture can be transferred axially to the axis of rotation of the stirring operation by means of the stirring operation. Preferably, the fluid volume of the reaction mixture is between 0.5 and 50 cubic meters, preferably between 1 and 30 cubic meters, more preferably between 2 and 20 cubic meters, preferably between 3 and 15 cubic meters and even more preferably between 4 and 10 In the range of cubic meters, more preferably 4.5 to 8 cubic meters, more preferably 5 to 7 cubic meters and more preferably 5.5 to 6.5 cubic meters.

If the agitator device consists of one or more axial transfer agitators, there is no restriction on the circulating volume flow rate. Preferably, if the agitator device is composed of one or more axial transfer agitators, the agitator device has a range of 0.05 to 10 m3 / s, more preferably 0.05 to 10 m3 / s, more preferably 0.1 to 6 m3 / s, more preferably 0.2 to 4 m3 / s, more preferably 0.4 to 3 m3 / s, more preferably 0.6 to 2.5 m3 / s, more preferably 0.8 to 2 m3 / s The circulating volume flow rate V _{z in the} range of 1 / 1.6, more preferably 1 to 1.6 m 3 / s, and more preferably 1.2 to 1.4 m 3 / s.

As already described above, the stirring operation transfers the reaction mixture axially to the axis of rotation of the stirring operation is a typical feature of the method of the present invention. There is no limitation on the configuration of the agitator device relative to the agitation tank, especially the position of the rotation axis of the agitator device relative to the surface of the agitator tank or the reaction mixture. Preferably, the agitator device conveys the reaction mixture towards the base of the agitation tank or towards the surface of the reaction mixture, preferably towards the base of the agitation tank.

As already described above, preferably, the agitator device consists of a plurality of axial transfer agitators. If the stirrer device is composed of a plurality of axial transfer agitators, these axial transfer agitators can independently transport the portion of the reaction mixture in any direction, for example, toward the base of the stirring tank or toward the surface of the reaction mixture. Here, preferably, all of the axial transfer agitators are directed toward the base of the stirring tank or the surface of the reaction mixture, and more preferably the reaction mixture is directed toward the base of the stirring tank.

If the agitator device is composed of a plurality of axial conveying agitators, there is no restriction on the positions of their rotation axes with respect to each other. Preferably, according to the aforementioned alternative, the agitator device is composed of a plurality of axial transfer agitators, wherein the rotation axes of the axial transfer agitators are parallel to each other. In addition, the axial transfer agitators may be in any configuration relative to each other; they may also have different rotation axes or the same rotation axis, and preferably, the agitators have the same rotation axis. In addition, two or more of the axial transfer agitators having the same rotation axis may be arranged one on top of the other, that is, offset from each other in the same rotation axis. This configuration may also include configurations spaced apart from each other by a superimposed agitator.

As already described above, there are no restrictions on the configuration of the agitator device relative to the agitation tank, and in particular, the position of the axis of rotation of the agitator device relative to the surface of the reaction mixture. Preferably, in the non-stirring state, the rotation axis of the agitator device is 10 ° to 90 °, preferably 30 ° to 90 °, more preferably 50 ° to 90 °, and more preferably 70 ° to the surface of the reaction mixture. To 90 °, more preferably 80 ° to 90 °, more preferably 85 ° to 90 °, wherein in the non-stirred state, more preferably, the rotation axis of the agitator device is at right angles to the surface of the reaction mixture.

If the stirrer device is composed of multiple axial transfer stirrers, in a non-stirred state, the rotation axis of an individual stirrer can each independently make any angle with respect to the surface of the reaction mixture. Preferably, in one of the alternatives mentioned above, the agitator device is composed of a plurality of axial transfer agitators, wherein in a non-stirred state, the rotation axis of the individual axial transfer agitator and the reaction mixture The surface is independently angled in the range of 10 ° to 90 °, preferably 30 ° to 90 °, more preferably 50 ° to 90 °, more preferably 70 ° to 90 °, more preferably 80 ° to 90 °, and more preferably 85 ° to 90 °, wherein in the non-stirred state, more preferably, the rotation axis of the individual axial transfer stirrer is at right angles to the surface of the reaction mixture.

Regardless of the above specific examples, there are no restrictions on the size and geometry of the mixing tank. Typically, a cylindrical stirring tank is used. The ratio of the surface area of the reaction mixture to the volume of the reaction mixture in a non-stirred state in contact with the atmosphere above the reaction mixture may be desirable. Preferably, the stirring tank has a cylindrical geometry and is in contact with the The ratio of the surface area of the reaction mixture to the volume of the reaction mixture in a non-stirred state in contact with the atmosphere above the reaction mixture is 5 to 0.05 D ^-1 , preferably 3 to 0.1 D ^-1 , more preferably 2 to 0.3 D ^-1 , more preferably 1.5 to 0.5 D ^-1 , more preferably 1.3 to 0.7 D ^-1 , more preferably 1.2 to 0.8 D ^-1, and more preferably 1.1 to 0.9 D ^-1 , where D is the inner diameter of the stirring tank.

In addition, at least in the case where the stirring tank has a cylindrical geometry, there is no limitation on the ratio of the filling height of the reaction mixture in the stirring tank to the inner diameter of the stirring tank. Preferably, the stirring tank has a cylindrical geometry, and the ratio of the filling height of the reaction mixture in the stirring tank to the inner diameter of the stirring tank is 0.05 to 5, preferably 0.1 to 3, more preferably 0.3 to 2, and more preferably Within the range of 0.5 to 1.5, more preferably 0.7 to 1.3, more preferably 0.8 to 1.2 and more preferably 0.9 to 1.1.

In addition, the agitation tank may contain other components, such as a baffle, which is also called an interrupter. It is particularly preferred to modify the method, such as shortening the reaction time or better mixing the components of the reaction mixture. The stirring tank preferably includes one or more baffles, wherein the one or more baffles preferably run parallel to the rotation axis of the stirring tank. More preferably, here, the one or more baffles extend across the entire length of the stirring tank in the direction of the axis of rotation of the stirring operation.

There are no restrictions on the one or more baffles themselves (if used), and it is therefore particularly possible to use any baffle known to those of ordinary skill in the art. Preferably, in the method of the present invention, one or more baffles in the form of flat iron bars are used, wherein the one or more flat iron bars are more preferably mounted on the wall of the stirring tank. In this case, the one or more flat iron bars may be mounted on the wall in any desired manner. Preferably, the one or more flat iron bars are installed at right angles to the wall of the mixing tank. In addition, in the case of using a plurality of flat iron bars, these flat iron bars may be arranged at different distances from each other, and preferably, they are installed on the wall of the stirring tank at the same distance from each other.

There is no limit to the number of baffles that can be present in the mixing tank. Preferably, the stirring tank contains 2 to 10 baffles, preferably 2 to 8, more preferably 4 to 6 and more preferably 4 baffles.

There is no restriction on the size of the one or more baffles, especially the width of the single baffle at its widest point relative to the diameter of the mixing tank at a right angle to the axis of rotation of the stirring operation. Preferably, the width of the baffle at its widest point is 0.01 to 0.3 times the diameter of the stirring tank at a right angle to the rotation axis of the stirring operation, preferably the diameter of the stirring tank at a right angle to the rotation axis of the stirring operation. 0.02 to 0.25 times, more preferably 0.04 to 0.2 times, more preferably 0.06 to 0.16 times, more preferably 0.08 to 0.14 times, and even more preferably 0.1 to 0.2 times.

Therefore, preferably, the stirring tank includes four baffles, wherein these baffles run parallel to the rotation axis of the stirring operation and preferably extend across the entire length of the stirring tank in the direction of the rotation axis of the stirring operation, and wherein It is preferable to use a flat iron bar as the baffle, wherein the flat iron bar is more preferably installed at a right angle to the wall of the stirring tank, and is particularly preferably installed on the wall of the stirring tank at the same distance from each other.

In addition, the stirring tank may include a duct as another component, and the stirring operation is performed in the duct. Preferably, the stirring tank includes this conduit, and there is no restriction on the size of the conduit or its configuration in the stirring tank. Preferably, the conduit, if used, terminates below the surface of the reaction mixture and above the base of the stirred tank. The distance between the upper end of the duct and the surface of the reaction mixture in the non-stirred state and the distance between the lower end of the duct and the base of the stirring tank may be different. Preferably, this distance is substantially the same. There are no restrictions on the distance between the upper end of the conduit and the surface of the reaction mixture in the non-stirred state, and the distance between the lower end of the conduit and the base of the stirring tank. Preferably, the distance is between 5% and 200% of the length of the catheter, preferably between 10% and 150% of the length of the catheter, more preferably between 15% and 100%, and even better Between 20% and 80%, more preferably between 25% and 60%, and more preferably between 30% and 40%. It is also preferred that one of the one or more axial transfer agitators together with the duct forms a jet mixer in each case.

In addition, the method of the present invention can be carried out in an inert gas atmosphere, wherein there is no limitation on the inert gas used. The atmosphere above the surface of the reaction mixture is preferably composed of an inert gas selected from the group consisting of CO ₂ and one or more gases, wherein the one or more gases are selected from the group consisting of an inert gas, CO, and N ₂ . Here, the CO ₂ content of the inert gas atmosphere may be selected as required, and preferably, the CO ₂ content of the inert gas atmosphere is 10% by volume or more, preferably 30% by volume or more, and more preferably 50% by volume or more. 70% by volume or more, 80% by volume or more, 90% by volume or more, 95% by volume or more, 98% by volume or more, 99% by volume % Or more, and more preferably 99.9% by volume or more.

There are no restrictions on the conditions in the stirring operation in the method of the present invention, especially the speed of the stirring operation. Preferably, the operating speed of the stirring system of between 5 and 1000 minutes ^{-1, -1} preferably from 10 to 700 minutes, more preferably from 30 to 500 minutes ^{-1, -1} more preferably from 50 to 200 minutes, more preferably 60 to 130 minutes ^-1 , more preferably 70 to 100 minutes ^-1 , and more preferably 75 to 85 minutes ^-1 .

There are no restrictions on the configuration of the agitator device, especially in combination with one or more of the specific examples mentioned above. As already described above, the agitator device may consist of one or more agitators. Preferably, the agitator device is composed of one or more agitators selected from the group consisting of a propeller agitator, an inclined blade agitator, an Archimedes agitator, a MIG agitator, and a cross-anchored agitator. The agitator or agitators are preferably selected from the group consisting of a propeller agitator with 2 to 6 blades and a pitched blade agitator with 2 to 8 blades, and more preferably selected from a propeller agitation with 2 to 4 blades It is more preferably selected from the group consisting of a propeller agitator with 3 blades and an inclined blade agitator with 4 blades. Particularly preferably, the agitator device comprises one or more inclined blade agitators, more preferably one inclined blade agitator, more preferably one inclined blade agitator having 2 to 8 blades, and even more preferably having 3 to A 6-blade oblique blade mixer and more preferably a 4-blade oblique blade mixer.

There is no restriction on the diisocyanate used in (i) to prepare the reaction mixture, provided that it is polymerizable in (ii). Preferably, the diisocyanate has the formula R (NCO) ₂ , wherein R is selected from the group consisting of straight or branched C ₃ -C ₁₅ alkyl, cycloaliphatic C ₅ -C ₂₀ alkyl, C ₆ -C ₁₈ aryl, A group consisting of a C ₇ -C ₂₀ aralkyl group and a C ₇ -C ₂₀ alkaryl group, and R is preferably selected from a linear or branched C ₃ -C ₈ alkyl group, a cycloaliphatic C ₅ -C ₁₀ alkyl group, C ₆ -C ₉ aryl, C ₇ -C ₁₅ aralkyl and C ₇ -C ₁₅ alkaryl groups, and R is more preferably selected from straight or branched C ₃ -C ₆ alkyl, cycloaliphatic Group C ₅ -C ₆ alkyl, C ₆ aryl, C ₇ -C ₁₂ aralkyl and C ₇ -C ₁₂ alkaryl.

Therefore, preferably, for the diisocyanate, it is selected from the group consisting of methylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentyl diisocyanate, Dipropyl ether diisocyanate, 1,5-diisocyanate-2,2-dimethylpentane, 1,6-diisocyanate-3-methoxyhexane, octamethylene diisocyanate, 1 2,5-diisocyanate-2,2,4-trimethylpentane, dynenonyl diisocyanate, decamethylene diisocyanate, 1,6-diisocyanate-3-butoxyhexane, 1,4-butanediol dipropyl ether diisocyanate, thiodihexyl diisocyanate, m-xylylene diisocyanate, xylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane 4,4'- Diisocyanate, 1,3-bis (1-isocyanato-1-methylethyl) benzene, toluene 2,4-diisocyanate, diphenylmethane 2,2'-diisocyanate, diphenylmethane 2 , 4'-diisocyanate and diphenylmethane 4,4'-diisocyanate, hexamethylene 1,6-diisocyanate and 1,12-diisocyanate dodecane, and mixtures thereof. In detail, the diisocyanate is preferably selected from the group consisting of tetramethylene 1,4-diisocyanate, hexamethylene 1,6-diisocyanate, dodecyl 1,12-diisocyanate, 1 1,4-diisocyanate cyclohexane, 1,6-diisocyanate-2,4,4-trimethylhexane, 1,6-diisocyanate-2,2,4-trimethylhexane Alkane, 2,2-bis (4-isocyanatecyclohexyl) propane, isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, 1,3-bis (1-isocyanate-1 -Methylethyl) benzene, toluene 2,4-diisocyanate, diphenylmethane 2,2'-diisocyanate, diphenylmethane 2,4'-diisocyanate, diphenylmethane 4,4'-di Isocyanates, and mixtures thereof. Therefore, it is particularly preferable that the reaction mixture contains 1,3-bis (1-isocyanato-1-methylethyl) benzene, and among them, the diisocyanate is more preferably 1,3-bis (1-isocyanato- 1-methylethyl) benzene.

There is no restriction on the amount of catalyst in the reaction mixture prepared in (i), provided that it is capable of polymerizing the diisocyanate to form the polycarbodiimide in (ii). Preferably, the amount of the catalyst in the reaction mixture prepared in (i) is from 0.01% to 2% by weight, preferably from 0.05% to 1% by weight, based on 100% by weight of the diisocyanate in the reaction mixture. More preferably 0.1% to 0.5% by weight, more preferably 0.15% to 0.35% by weight, more preferably 0.2% to 0.3% by weight, more preferably 0.22% to 0.27% by weight, and even more preferably 0.23% to 0.25% by weight. Within range.

There is no restriction per se on the catalyst that acts as a reaction mixture in (i), provided that it is capable of polymerizing the diisocyanate in (ii) to form a polycarbodiimide. Preferably, the catalyst comprises one or more organophosphorus compounds, and the one or more organophosphorus compounds are preferably selected from the group consisting of phosphin, phosphin oxide, phosphine, phosphopentene oxide and mixtures thereof, The one or more organic phosphorus compounds are preferably selected from the group consisting of diphenylphosphonic acid and its salts, bis (2,4-trimethylpentyl) monophosphonic acid, tributylphosphine, triisobutylphosphine sulfide, tris Alkylphosphine oxide, triphenylphosphine, tetraphenylphosphine bromide, tetrabutylphosphine chloride, tetrabutylphosphine bromide, bis (2,4,4-trimethylpentyl) dithiophosphonic acid A group consisting of bis (2,4,4-trimethylpentyl) monothiophosphonic acid, phosphin oxide, and mixtures thereof. The one or more organic phosphorus compounds are more preferably selected from diphenylphosphonic acid and Salt, bis (2,4-trimethylpentyl) monophosphonic acid, tributylphosphine, triisobutylphosphine sulfide, trioctylphosphine oxide, trihexylphosphine oxide, triphenylphosphine, tetrabenzene Phosphine bromide, tetrabutylphosphine chloride, tetrabutylphosphine bromide, bis (2,4,4-trimethylpentyl) dithiophosphonic acid, bis (2,4,4-trimethyl Amyl) monothiophosphonic acid, phosphin oxide, and mixtures thereof Group composed of, more preferably wherein the catalyst comprises one or more oxides of phosphorus Lin, Lin and one or more phosphorus oxide catalyst more preferably used.

If phosphin oxide is used as a catalyst for the preparation of the reaction mixture in (i), there are no restrictions thereon, provided that it is capable of polymerizing the diisocyanate in (ii) to form a polycarbodiimide. Preferably, the phosphin oxide comprises one or more phosphin oxides of formula (I)

Wherein R ¹ and R ² are independently H or an optionally substituted aliphatic of C ₁ -C ₁₅ alkyl, cycloaliphatic C ₅ -C ₁₅ alkyl, C ₆ -C ₁₅ aryl, C ₇ -C ₁₅ Aralkyl or C ₇ -C ₁₅ alkylaryl, wherein R ¹ and R ^{2 are} independently preferably H or C ₁ -C ₁₀ alkyl.

If one or more phosphin oxides of formula (I) are used as catalysts for the preparation of the reaction mixture in (i), then R ^{1 is} preferably H, optionally substituted aliphatic C ₁ -C ₁₀ alkyl Or C ₆ -C ₁₅ aryl, preferably substituted methyl, ethyl, propyl, phenyl or benzyl, and more preferably methyl or phenyl.

If one or more phosphin oxides of the formula (I) are used as catalysts for the preparation of the reaction mixture in (i), then R ^{2 is} preferably H or optionally substituted aliphatic C ₁ -C ₁₀ alkyl Is preferably H or optionally substituted methyl, ethyl or propyl, and more preferably H or methyl.

Particularly preferably, if one or more phosphin oxides of the formula (I) are used as a catalyst for preparing a reaction mixture in (i), the phosphin oxides are selected from the group consisting of: 3-methyl-1 -Phenyl-2-phosphine 1-oxide, 1-phenyl-2-phosphine 1-oxide, 1-methyl-2-phosphine 1-oxide, 1,3-dimethyl-2 -Phosphine 1-oxide, 1-ethyl-3-methyl-2-phosphine 1-oxide, and mixtures thereof, wherein the phosphine oxide preferably contains 1-methyl-2-phosphine 1- Of the oxides, the phosphine oxide is more preferably 1-methyl-2-phosphine 1-oxide, and more preferably, the catalyst used is 1-methyl-2-phosphine 1-oxide.

The reaction mixture prepared in (i) and used in (ii) may contain other substances or compounds, provided that the method is not impaired in a manner that makes it impossible to perform polymerization in (ii). Preferably, the reaction mixture prepared in (i) and used in (ii) comprises a solvent, and the solvent is more preferably selected from the group consisting of aromatic hydrocarbons, amidines, halogenated hydrocarbons, ethers, cyclic carbonates, and mixtures thereof. And the solvent is more preferably selected from the group consisting of toluene, xylene, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dichloromethane, chloroform, dichloroethane, tetrachloromethane A group of ethyl chloride, tetrahydrofuran, ethyl carbonate, propyl carbonate and mixtures thereof.

Relative to the reaction mixture prepared in (i) and used in (ii), more preferably, in addition to the one or more diisocyanates and catalysts, it contains less than 10% by weight, more preferably less than 5% by weight, more preferably Other compounds less than 3% by weight, more preferably less than 1% by weight, more preferably less than 0.5% by weight, more preferably less than 0.1% by weight, more preferably less than 0.05% by weight, and particularly preferably less than 0.01% by weight.

In method (ii), it is carried out in a stirred tank by heating the reaction mixture prepared in (i) to a temperature in the range of 20 to 250 ° C. under a pressure in the range of 20 to 800 mbar. Polymerization of diisocyanates to form polycarbodiimides. Here, it is possible to prepare polycarbodiimides having different degrees of polymerization, in which the degree of polymerization is not limited in any way. Preferably, the polycarbodiimide obtained in (ii) has a range of 1 to 20, more preferably 2 to 15, more preferably 3 to 12, more preferably 3 to 10, more preferably 3 to 8, more The degree of polymerization is preferably 3 to 6, and more preferably 3 to 5.

Part (ii) of the method yields a product mixture comprising polycarbodiimide. This product mixture typically has characteristic properties that can be determined by means of standard test methods, in particular the NCO content, where the NCO content is not subject to any restrictions.

Preferably, the NCO content of the product mixture is determined according to DIN EN 1242. More preferably, the product mixture obtained in (ii) has an NCO content in the range of 0.1% to 25% by weight, more preferably 0.5% to 23% by weight, more preferably, based on the weight of the polycarbodiimide. 1% to 21% by weight, more preferably 5% to 19% by weight, more preferably 8% to 17% by weight, still more preferably 10% to 15% by weight, and particularly preferably 11% to 13% by weight.

Typically, the reaction time in (ii) (ie, especially in the polymerization reaction) matches the decidable NCO content of the product mixture. In this context, it is preferably 6 to 96 hours, more preferably 8 to 72 hours, more preferably 10 to 48 hours, more preferably 12 to 36 hours, and more preferably 14 to 30 hours in (ii). Reaction times in the range of hours, more preferably 16 to 24 hours, and particularly preferably 18 to 22 hours.

Therefore, it is particularly preferable that the NCO content of the product mixture obtained in (ii) is 0.1 to 25% by weight, more preferably 0.5 to 23% by weight, more preferably based on the weight of the polycarbodiimide. 1% to 21% by weight, more preferably 5% to 19% by weight, more preferably 8% to 17% by weight, more preferably 10% to 15% by weight, and particularly preferably 11% to 13% by weight Content of NCO within 6 to 96 hours, preferably 8 to 72 hours, more preferably 10 to 48 hours, more preferably 12 to 36 hours, and more preferably 14 to 30 hours in (ii) , Better after 16 to 24 hours, and better after 18 to 22 hours of response time.

Preferably, the color index of the polycarbodiimide is determined according to DIN 6162. More preferably, the obtained polycarbodiimide has a color index of 20 or less, preferably 10 or less and more preferably 5 or less.

There is no limitation on the scope of the method in (ii) of the method. Continuous or batch procedures in this method are conceivable. Preferably, (ii), that is, polymerization, is performed in batches.

The polymerization in (ii) is carried out by heating the reaction mixture prepared in (i) to a temperature in the range of 20 to 250 ° C. under a pressure in the range of 20 to 800 mbar. Depending on the conditions selected, it is possible to provide cooling in order to ensure resource-saving recycling of, for example, gaseous solvents or other compounds that escape from (ii). The polymerization in (ii) is more preferably carried out under reflux cooling.

As already described above, the method of the invention can be carried out in an inert gas atmosphere, with no restrictions on the inert gas used. Further, in (ii), the polymerization may be performed in the presence of an inert gas, wherein the inert gas is preferably continuously introduced into the reaction mixture. If an inert gas is introduced into the reaction mixture, it is preferably at a flow rate in the range of 0.1 to 100 vol / hr, more preferably 0.5 to 80 vol / hr, more preferably 1 to 50 vol / hr, more A flow rate in the range of preferably 5 to 40 vol / hr, more preferably 10 to 30 vol / hr, more preferably 15 to 25 vol / hr, and more preferably 18 to 22 vol / hr introduces an inert gas into the reaction mixture, where V Represents the volume of the reaction mixture.

There are no restrictions on the inert gas itself. Preferably, the inert gas comprises one or more gases selected from the group consisting of nitrogen (N ₂ ), helium (He), neon (Ne), argon (Ar), carbon dioxide (CO ₂ ), and mixtures thereof, The one or more gases are preferably selected from the group consisting of nitrogen (N ₂ ), argon (Ar), carbon dioxide (CO ₂ ), and mixtures thereof, and more preferably selected from the group consisting of nitrogen (N ₂ ), carbon dioxide (CO ₂ ), and For a group consisting of a mixture, the inert gas used is more preferably nitrogen (N ₂ ) or carbon dioxide (CO ₂ ), and more preferably nitrogen (N ₂ ).

There is no limitation on the manner in which the inert gas is introduced into the reaction mixture. Preferably, the inert gas is introduced into the reaction via one or more immersion tubes, via holes in the base and / or wall of the stirring tank, via shafts of the stirrer device and / or holes in the stirrer, and / or via gas rings. In the mixture, the inert gas is preferably introduced through an air ring, and the holes in the air ring are preferably directed partially and preferably completely toward the base of the stirring tank.

In addition, preferably, considering the introduction of an inert gas, the agitator device is provided with holes in the shaft and / or the agitator, preferably in the shaft and the agitator, for introducing at least a part of the inert gas.

In addition, it is particularly preferred that, in the process (ii) of the present invention, no gas and especially no inert gas is introduced into the reaction mixture.

As already disclosed above, the method described in particular according to specific example 1 below may comprise further method steps. Preferably, the method according to one of the foregoing specific examples and including method steps (i) and (ii) only in that sequence includes other steps (iii), (iv), and (v), wherein (iii) In this step, the catalyst is separated from the product mixture by distilling the product mixture obtained in (ii) to obtain a first bottom product and a first distillate, wherein the first bottom product comprises polycarbodiimide And a part of the catalyst, and the first distillate includes another part of the catalyst, and in (iv), an entraining agent is added to the first bottom product obtained in (iii) to obtain A mixture in which the gas transfer agent has a lower boiling point than the polycarbodiimide, and in (v) the catalyst is separated from the mixture by distillation of the mixture obtained in (iv) to obtain a second A bottom product and a second distillate, wherein the second bottom product includes a portion of a polycarbodiimide and a catalyst, and the second distillate includes another portion of a catalyst and a gas transfer agent.

There is no restriction on the gas transport agent itself and its properties, especially its boiling point under standard conditions, provided that it is suitable for separation in (v). Preferably, the gas transport agent has a boiling point in the range of 150 to 350 ° C. More preferably, the gas transport agent does not have any amine groups -NH- and / or -OH groups and / or -SH groups and / or -COOH groups. Particularly preferably, the gas transport agent comprises a diisocyanate, preferably a diisocyanate according to one of the foregoing specific examples or any of the following specific examples 29 and 30, wherein the gas transport agent is more preferably composed of one or more diisocyanates. An isocyanate composition, wherein the gas transport agent is more preferably composed of a diisocyanate according to one of the foregoing specific examples or one of the following specific examples 29 and 30.

For the other method steps (iii) and (v) mentioned above in terms of the conditions to be adopted, there are no restrictions, especially for temperature and pressure, provided that (iii) and / or (v) can be achieved or improved In the separation. Preferably, (iii) and / or (v), more preferably (iii) and (v), the distillation is carried out at a temperature in the range of 100 to 400 ° C, preferably 130 to 350 ° C and more preferably 150 to 250 ° C. Carry on. More preferably, the distillation in (iii) and / or (v), more preferably (iii) and (v) is in the range of 0.1 to 800 mbar, preferably 0.1 to 500 mbar, and more preferably 0.1 to 300 mbar. Under pressure in the range. Therefore, it is particularly preferable that the distillation in (iii) and / or (v), preferably (iii) and (v) is at 100 to 400 ° C, preferably 130 to 350 ° C, and more preferably 150 to 250 ° C. It is carried out at a temperature in the range and at a pressure in the range of 0.1 to 800 mbar, preferably 0.1 to 500 mbar, and more preferably 0.1 to 300 mbar. More preferably, the distillation in (iii) and / or (v), preferably (iii) and (v) is performed at a temperature in the range of 150 to 250 ° C and a pressure in the range of 0.1 to 300 mbar. .

The other method steps (iv) and (v) mentioned may be repeated in order to achieve or improve a substantially extremely complete separation in (v). Preferably, (iv) and (v) are repeated; preferably, (iv) and (v) are repeated 1 to 10 times, more preferably 1 to 7 times, more preferably 1 to 5 times, more preferably 1 to 4 times , More preferably 1 to 3 times, more preferably 1 to 2 times, and more preferably repeating (iv) and (v) once.

In particular, in order to implement the resource saving method, it is better to perform step (vi) following (v) in addition to other method steps (iii), (iv), and (v), in which (vi), in At least some of the first and / or second distillates obtained in (i), preferably all of the first and / or second distillates obtained in (i) are recycled for use in generating a reaction mixture .

As described in detail above, the method of the present invention relates to the preparation of polycarbodiimide. In addition, the obtained polycarbodiimide may alternatively be further transformed by a person having ordinary knowledge in the technical field. For example, the polycarbodiimide obtained by the method of the present invention can be used as a starting material for synthesizing other substances, for example, in organic synthesis. Preferably, the polycarbodiimide is further reacted with a compound selected from the group consisting of a monohydric alcohol (ie, a monohydric alcohol containing an alcoholic hydroxyl group), a glycol, a polyoxyalkylene alcohol, a monoamine, and Mixtures, the compounds are preferably selected from the group consisting of monohydric alcohols, glycols, polyethylene glycols, polypropylene glycols, monoamines, and mixtures thereof.

Finally, the invention also relates to a composition comprising a polycarbodiimide obtained from the method described above. The simple condition of this composition is the product mixture that has been obtained from (ii) and the bottom product obtained from (iii) or (v). Therefore, the present invention relates in particular to a polycarbodiimide composition obtainable by and / or by a method according to one of the specific examples described above.

As already described above, polycarbodiimide typically has characteristic properties that can be determined by means of standard test methods, especially NCO content and color index, where NCO content and color index are not subject to any restrictions herein.

Preferably, the NCO content of the polycarbodiimide composition is determined according to DIN EN 1242. In addition, preferably, the polycarbodiimide composition has an NCO content in the range of 0.1% to 25% by weight, more preferably 0.5% to 23% by weight, based on the weight of the polycarbodiimide composition. 1 to 21% by weight, 5 to 19% by weight, 8 to 17% by weight, 10 to 15% by weight, and 11 to 13% by weight are more preferable %.

Preferably, the color index of the polycarbodiimide composition is determined according to DIN 6162. More preferably, the polycarbodiimide composition has a color index of 20 or less, preferably 10 or less, and more preferably 5 or less.

The invention is also characterized by the following specific examples, including individual and separate combinations of specific examples indicated by respective dependencies:
1. A method for preparing a polycarbodiimide, comprising (i) preparing a reaction mixture comprising a diisocyanate and a catalyst, and (ii) in a stirred tank by a pressure in the range of 20 to 800 mbar The diisocyanate is polymerized by heating the reaction mixture prepared in (i) to a temperature in the range of 20 to 250 ° C to form the polycarbodiimide, wherein a stirrer device is used to stir the reaction mixture during the polymerization. ,
The method includes axially transferring the reaction mixture to the axis of rotation of the stirring operation by means of the stirring operation.
2. The method according to specific example 1, wherein in (ii), the reaction mixture is heated to 40 to 230 ° C, preferably 60 to 210 ° C, more preferably 80 to 200 ° C, more preferably 100 to 190 ° C, A temperature in the range of 120 to 180 ° C, more preferably 130 to 170 ° C, more preferably 145 to 155 ° C, and more preferably 140 to 160 ° C.
3. The method according to the specific example 1 or 2, wherein in (ii), it is 50 to 750 mbar, preferably 100 to 600 mbar, more preferably 150 to 500 mbar, more preferably 200 to 400 mbar. The reaction mixture is heated at a pressure in the range of more preferably 250 to 350 mbar, more preferably 270 to 330 mbar, and more preferably 290 to 310 mbar.
4. The method according to any one of the specific examples 1 to 3, wherein in (ii), the reaction mixture is heated at the temperature for 6 to 96 hours, preferably 8 to 72 hours, more preferably 10 to 48. Hours, more preferably 12 to 36 hours, more preferably 14 to 30 hours, more preferably 16 to 24 hours, and more preferably 18 to 22 hours.
5. The method according to any one of the specific examples 1 to 4, wherein the agitator device is composed of one or more axial conveying agitators, preferably 1 to 4, more preferably 1 to 3, more Preferably, one or two axial transfer agitators are used, and it is particularly preferred to use one axial transfer agitator in (ii).
6. The method according to the specific example 5, wherein the agitator device is composed of an axial conveying agitator, and wherein the agitator has a range of 0.05 to 5, preferably 0.1 to 4, more preferably 0.3 to 3, and more preferably 0.5. Cycling coefficients k _{z in the} range of 2.5, more preferably 0.6 to 2, more preferably 0.7 to 1.5, more preferably 0.8 to 1.3, and more preferably 0.9 to 1.1.
7. The method according to the specific example 6, wherein the ratio of the diameter of the stirrer to the internal diameter of the stirring tank is 0.05 to 0.85, preferably 0.1 to 0.8, more preferably 0.2 to 0.75, more preferably 0.3 to 0.7, more preferably 0.35. To 0.65, more preferably 0.4 to 0.6, and more preferably 0.45 to 0.55.
8. The method according to the specific example 5, wherein the agitator device is composed of a plurality of axial transfer agitators, and wherein the plurality of agitators have a range of 0.05 to 5, preferably 0.1 to 4, and more preferably 0.3 to 3 , More preferably 0.5 to 2.5, more preferably 0.6 to 2, more preferably 0.7 to 1.5, more preferably 0.8 to 1.3, and more preferably a coefficient of circulation k _{z in the} range of 0.9 to 1.1.
9. The method according to the specific example 8, wherein the ratio of the average diameter of the plurality of agitators to the inner diameter of the agitating tank is 0.05 to 0.85, preferably 0.1 to 0.8, more preferably 0.2 to 0.75, more preferably 0.3 to 0.7, more preferably 0.35 to 0.65, more preferably 0.4 to 0.6, and more preferably 0.45 to 0.55.
10. The method according to any one of the specific examples 5 to 9, wherein the diameter of the one stirrer or the average diameter of the plurality of stirrers is 10 to 500 cm, preferably 30 to 300 cm, more preferably 50 To 200 cm, more preferably 70 to 150 cm, more preferably 80 to 120 cm, and more preferably 90 to 110 cm.
11. The method according to any one of specific examples 5 to 10, wherein the internal diameter of the stirring tank is 20 to 5000 cm, preferably 40 to 3000 cm, more preferably 60 to 2000 cm, more preferably 80 to 1500 In the range of cm, preferably 100 to 1000 cm, more preferably 120 to 500 cm, more preferably 140 to 300 cm, more preferably 160 to 250 cm and more preferably 180 to 220 cm.
12. The method according to any one of the specific examples 1 to 11, wherein the fluid volume of the reaction mixture is 0.5 to 50 m3, preferably 1 to 30 m3, more preferably 2 to 20 m3 , Preferably in the range of 3 to 15 cubic meters, more preferably 4 to 10 cubic meters, more preferably 4.5 to 8 cubic meters, more preferably 5 to 7 cubic meters and even more preferably 5.5 to 6.5 cubic meters.
13. The method according to any one of the specific examples 5 to 12, wherein the agitator device has a temperature of 0.05 to 10 m3 / s, preferably 0.05 to 10 m3 / s, more preferably 0.1 to 6 m3 M / s, more preferably 0.2 to 4 m3 / s, more preferably 0.4 to 3 m3 / s, more preferably 0.6 to 2.5 m3 / s, more preferably 0.8 to 2 m3 / s, more Circulating volume flow rate V _{z in the} range of 1 to 1.6 m / s and more preferably 1.2 to 1.4 m / s.
14. The method according to any one of the specific examples 1 to 13, wherein the stirrer device transfers the reaction mixture toward the base of the stirring tank or toward the surface of the reaction mixture, preferably toward the base of the stirring tank.
15. The method according to any one of the specific examples 1 to 14, wherein the stirrer device is composed of a plurality of axial transfer agitators, and the plurality of axial transfer agitators independently transport the reaction mixture toward the stirring tank The substrate or the surface facing the reaction mixture, wherein preferably all the axial transfer agitators transfer the reaction mixture toward the substrate of the stirring tank or the surface of the reaction mixture, preferably toward the substrate of the stirring tank .
16. The method according to any one of the specific examples 1 to 15, wherein the agitator device is composed of a plurality of axial transfer agitators, wherein the rotation axes of the respective axial transfer agitators are parallel to each other, wherein the The isometric conveying agitator preferably has the same axis of rotation and more preferably assumes a replication offset configuration on top of the other.
17. The method according to any one of the specific examples 1 to 16, wherein the rotation axis of the agitator device is 10 ° to 90 °, preferably 30 ° to 90, with the surface of the reaction mixture in a non-stirred state. °, more preferably 50 ° to 90 °, more preferably 70 ° to 90 °, more preferably 80 ° to 90 °, more preferably 85 ° to 90 °, and more preferably, the rotation axis of the agitator device and the The surface of the reaction mixture in a non-stirred state is at a right angle.
18. The method according to any one of the specific examples 1 to 17, wherein the agitator device is composed of a plurality of axial transfer agitators, and the rotation axes of the individual axial transfer agitators are independent of non-agitating The surface of the reaction mixture in the state is 10 ° to 90 °, preferably 30 ° to 90 °, more preferably 50 ° to 90 °, more preferably 70 ° to 90 °, more preferably 80 ° to 90 °, more preferably An angle in the range of 85 ° to 90 °, more preferably, the axis of rotation of the individual axial transfer stirrers is at right angles to the surface of the reaction mixture in a non-stirred state.
19. The method according to any one of the specific examples 1 to 18, wherein the stirring tank has a cylindrical geometry and is in contact with the atmosphere above the reaction mixture, and the surface area of the reaction mixture in a non-stirred state and the The volume ratio of the reaction mixture is 5 to 0.05 D ^-1 , preferably 3 to 0.1 D ^-1 , more preferably 2 to 0.3 D ^-1 , more preferably 1.5 to 0.5 D ^-1 , more preferably 1.3 to 0.7 D ^-1 , In the range of more preferably 1.2 to 0.8 D ^-1 and more preferably 1.1 to 0.9 D ^-1 , where D is the inner diameter of the stirring tank.
20. The method according to any one of the specific examples 1 to 19, wherein the stirring tank has a cylindrical geometry, and the ratio of the filling height of the reaction mixture in the stirring tank to the inner diameter of the stirring tank is between 0.05 to 5, preferably 0.1 to 3, more preferably 0.3 to 2, more preferably 0.5 to 1.5, more preferably 0.7 to 1.3, more preferably 0.8 to 1.2, and more preferably 0.9 to 1.1.
21. The method according to any one of the specific examples 1 to 20, wherein the stirring tank comprises one or more baffles, wherein the one or more baffles preferably run parallel to a rotation axis of the stirring operation Preferably, the one or more baffles extend across the entire length of the stirring tank in the direction of the rotation axis of the stirring operation.
22. The method according to specific example 21, wherein the one or more baffles are flat iron bars, wherein the one or more flat iron bars are preferably installed on the wall of the stirring tank, wherein the one or more Flat iron bars are installed at right angles to the wall of the mixing tank, wherein the flat iron bars are preferably installed on the wall of the mixing tank at the same distance from each other.
23. The method according to the specific example 21 or 22, wherein the stirring tank comprises 2 to 10 baffles, preferably 2 to 8, more preferably 4 to 6 and more preferably 4 baffles.
24. The method according to any one of specific examples 21 to 23, wherein the width of the baffle at its widest point is 0.01 to 0.3 times the diameter of the stirring tank at a right angle to the rotation axis of the stirring operation , Preferably 0.02 to 0.25 times the diameter of the stirring tank at a right angle to the rotation axis of the stirring operation, more preferably 0.04 to 0.2 times, more preferably 0.06 to 0.16 times, more preferably 0.08 to 0.14 times, more preferably 0.1 To 0.12 times.
25. The method of any one of specific examples 1 to 24, wherein the stirring tank comprises a conduit in which the stirring operation is performed, wherein the conduit terminates below the surface of the reaction mixture and above the base of the stirring tank, The distance between the upper end of the conduit and the surface of the reaction mixture in a non-stirred state and the distance between the lower end of the conduit and the base of the stirring tank are preferably the same, and the upper end of the conduit and the The respective distances between the surface of the reaction mixture in the non-stirred state and the lower end of the conduit and the base of the stirring tank are preferably between 5% and 200% of the length of the conduit, preferably Between 10% and 150% of the length of the catheter, more preferably between 15% and 100%, more preferably between 20% and 80%, more preferably between 25% and 60%, and more It is preferably between 30% and 40%, with one of the one or more axial transfer agitators preferably forming a jet mixer with a conduit in each case.
26. The method according to any one of specific examples 1 to 25, wherein the atmosphere above the surface of the reaction mixture is composed of CO ₂ and one or more gases selected from the group consisting of inert gases, CO and N ₂ Inert gas atmosphere, wherein the CO ₂ content of the inert gas atmosphere is 10% by volume or more, preferably 30% by volume or more, more preferably 50% by volume or more, more preferably 70% by volume or more, more preferably 80% by volume or more, 90% by volume or more, 95% by volume or more, 98% by volume or more, 99% by volume or more, and 99.9% by volume or more More.
27. Specific examples of a method of claim, wherein the speed of the stirring operation of the system of any of 1 to 26 is between 5 and 1000 minutes ^{-1, -1} preferably from 10 to 700 minutes, more preferably from 30 to 500 minutes ^{- 1} , more preferably 50 to 200 minutes ^-1 , more preferably 60 to 130 minutes ^-1 , more preferably 70 to 100 minutes ^-1 , and even more preferably 75 to 85 minutes ^-1 .
28. The method according to any one of the specific examples 1 to 27, wherein the stirrer device is selected from the group consisting of a propeller stirrer, an inclined blade stirrer, an Archimedes stirrer, a MIG stirrer, and a cross-anchored stirrer. One or more agitators composed of a group, the one or more agitators are preferably selected from the group consisting of a propeller agitator having 2 to 6 blades and an inclined blade agitator having 2 to 8 blades, The one or more agitators are more preferably selected from the group consisting of a propeller agitator having 2 to 4 blades and a pitched blade agitator having 3 to 6 blades, and the one or more agitators are more preferably selected from the group consisting of A group of three-blade propeller agitators and four-blade oblique blade agitators. The agitator device is preferably composed of one or more oblique blade agitators, more preferably one oblique blade agitator, and even better. It consists of one inclined-blade agitator with 2 to 8 blades, more preferably one inclined-blade agitator with 3 to 6 blades, and more preferably one inclined-blade agitator with 4 blades.
29. The method according to any one of the specific examples 1 to 28, wherein the diisocyanate has the formula R (NCO) ₂ , wherein R is selected from the group consisting of a linear or branched C ₃ -C ₁₅ alkyl group, a cycloaliphatic C ₅ -C ₂₀ alkyl, C ₆ -C ₁₈ aryl, C ₇ -C ₂₀ aralkyl and C ₇ -C ₂₀ alkaryl, R is preferably selected from the group consisting of straight or branched C ₃ -C ₈ alkyl, cycloaliphatic C ₅ -C ₁₀ alkyl, C ₆ -C ₉ aryl, C ₇ -C ₁₅ aralkyl and C ₇ -C ₁₅ alkaryl, and R is more preferably selected from the group consisting of a straight-chain or branched-chain C ₃ -C ₆ alkyl, cycloaliphatic C ₅ -C ₆ alkyl, C ₆ aryl, C ₇ -C ₁₂ aralkyl and C ₇ -C ₁₂ alkaryl group consisting of the group.
30. The method according to any one of the specific examples 1 to 29, wherein the diisocyanate is selected from the group consisting of methylene diisocyanate, dimethyl methylene diisocyanate, trimethylene diisocyanate, tetramethylene Diisocyanate, pentyl diisocyanate, dipropyl ether diisocyanate, 1,5-diisocyanate-2,2-dimethylpentane, 1,6-diisocyanate-3-methoxyhexane Alkane, octamethylene diisocyanate, 1,5-diisocyanate-2,2,4-trimethylpentane, dynenonyl diisocyanate, decamethylene diisocyanate, 1,6-diisocyanate Acid-3-butoxyhexane, 1,4-butanediol dipropyl ether diisocyanate, thiodihexyl diisocyanate, m-xylene diisocyanate, xylene diisocyanate, isophorone diisocyanate , Dicyclohexylmethane 4,4'-diisocyanate, 1,3-bis (1-isocyanato-1-methylethyl) benzene, toluene 2,4-diisocyanate, diphenylmethane 2,2 '-Diisocyanate, diphenylmethane 2,4'-diisocyanate and diphenylmethane 4,4'-diisocyanate, hexamethylene 1,6-diisocyanate, and 1,12-diisocyanate dodecane , And its mixtures, the two different The cyanate is preferably selected from the group consisting of tetramethylene 1,4-diisocyanate, hexamethylene 1,6-diisocyanate, dodecyl 1,12-diisocyanate, 1,4- Diisocyanate cyclohexane, 1,6-diisocyanate-2,4,4-trimethylhexane, 1,6-diisocyanate-2,2,4-trimethylhexane, 2 , 2-bis (4-isocyanatocyclohexyl) propane, isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, 1,3-bis (1-isocyanato-1-methyl) Ethyl) benzene, toluene 2,4-diisocyanate, diphenylmethane 2,2'-diisocyanate, diphenylmethane 2,4'-diisocyanate, diphenylmethane 4,4'-diisocyanate and Mixture, wherein the reaction mixture more preferably comprises 1,3-bis (1-isocyanato-1-methylethyl) benzene, wherein the diisocyanate is more preferably 1,3-bis (1-isocyanato 1-methylethyl) benzene.
31. The method according to any one of the specific examples 1 to 30, wherein the amount of the catalyst in the reaction mixture prepared in (i) is 0.01% by weight based on 100% by weight of the diisocyanate in the reaction mixture. % To 2% by weight, preferably 0.05% to 1% by weight, more preferably 0.1% to 0.5% by weight, more preferably 0.15% to 0.35% by weight, more preferably 0.2% to 0.3% by weight, more preferably 0.22% by weight % To 0.27% by weight, and more preferably in the range of 0.23% to 0.25% by weight.
32. The method according to any one of the specific examples 1 to 31, wherein the catalyst comprises one or more organic phosphorus compounds, and the one or more organic phosphorus compounds are preferably selected from the group consisting of phosphorus phosphorus, phosphorus phosphorus oxidation Compounds, phosphine, phosphocyclopentene oxide and mixtures thereof; the one or more organic phosphorus compounds are preferably selected from the group consisting of diphenylphosphonic acid and its salts, bis (2,4-trimethyl (Pentyl) monophosphonic acid, tributylphosphine, triisobutylphosphine sulfide, trialkylphosphine oxide, triphenylphosphine, tetraphenylphosphine bromide, tetrabutylphosphine chloride, tetrabutylphosphine bromide Compounds, bis (2,4,4-trimethylpentyl) dithiophosphonic acid, bis (2,4,4-trimethylpentyl) monothiophosphonic acid, phosphin oxide and mixtures thereof; The one or more organophosphorus compounds are more preferably selected from the group consisting of diphenylphosphonic acid and its salts, bis (2,4-trimethylpentyl) monophosphonic acid, tributylphosphine, triisobutyl Phosphine sulfide, trioctylphosphine oxide, trihexylphosphine oxide, triphenylphosphine, tetraphenylphosphine bromide, tetrabutylphosphine chloride, tetrabutylphosphine bromide, bis (2,4,4 -Trimethylpentyl) Thiophosphonic acid, bis (2,4,4-trimethylpentyl) monothiophosphonic acid, phosphin oxide and mixtures thereof, wherein the catalyst preferably comprises one or more phosphin oxides, and one or Multiple phosphin oxides are more preferred as catalysts.
33. The method of embodiment 32, wherein the phosphin oxide comprises one or more phosphin oxides of formula (II)

Wherein R ¹ and R ^{2 are} independently H or optionally substituted aliphatic C ₁ -C ₁₅ alkyl, cycloaliphatic C ₅ -C ₁₅ alkyl, C ₆ -C ₁₅ aryl, C ₇ -C ₁₅ Aralkyl or C ₇ -C ₁₅ alkylaryl, wherein R ¹ and R ^{2 are} independently preferably H or C ₁ -C ₁₀ alkyl.
34. The method of Specific examples 32 or 33, wherein R ¹ is H, optionally substituted aliphatic of C ₁ -C ₁₀ alkyl or C ₆ -C ₁₅ aryl group, preferably of optionally substituted Methyl, ethyl, propyl, phenyl or benzyl, more preferably methyl or phenyl.
35. The method according to any one of the specific examples 32 to 34, wherein R ² is H or optionally substituted aliphatic C ₁ -C ₁₀ alkyl, preferably H or optionally substituted methyl , Ethyl or propyl, more preferably H or methyl.
36. The method according to any one of the specific examples 32 to 35, wherein the phosphine oxide is selected from the group consisting of 3-methyl-1-phenyl-2-phosphine 1-oxide, 1 -Phenyl-2-phosphine 1-oxide, 1-methyl-2-phosphine 1-oxide, 1,3-dimethyl-2-phosphine 1-oxide, 1-ethyl-3 -Methyl-2-phosphine 1-oxide, and mixtures thereof, wherein the phosphine oxide preferably comprises 1-methyl-2-phosphine 1-oxide, wherein the phosphine oxide is more preferably 1 -Methyl-2-phosphine 1-oxide, and more preferably, 1-methyl-2-phosphine 1-oxide is used as a catalyst.
37. The method according to any one of the specific examples 1 to 36, wherein the reaction mixture prepared in (i) and used in (ii) comprises a solvent, and the solvent is preferably selected from the group consisting of Solvents: aromatic hydrocarbons, amidines, halogenated hydrocarbons, ethers, cyclic carbonates, and mixtures thereof. The solvent is preferably selected from the group consisting of toluene, xylene, N-methylpyrrolidone, dimethyl Formamidine, dimethylacetamide, dichloromethane, chloroform, dichloroethane, tetrachloroethane, tetrahydrofuran, ethylene carbonate, propylene carbonate, and mixtures thereof.
38. The method according to any one of specific examples 1 to 37, wherein in addition to the one or more diisocyanates and the catalyst, the reaction mixture prepared in (i) and used in (ii) contains less than 10 Wt%, preferably less than 5 wt%, more preferably less than 3 wt%, more preferably less than 1 wt%, more preferably less than 0.5 wt%, more preferably less than 0.1 wt%, more preferably less than 0.05 wt%, and more preferably less than 0.01% by weight of other compounds.
39. The method according to any one of the specific examples 1 to 38, wherein the polycarbodiimide obtained in (ii) has a range of 1 to 20, preferably 2 to 15, more preferably 3 to 12, more preferably 3 to 10, more preferably 3 to 8, more preferably 3 to 6, and more preferably a degree of polymerization in the range of 3 to 5.
40. The method according to any one of the specific examples 1 to 39, wherein the product mixture obtained in (ii) has a content of 0.1% to 25% by weight, 0.5% by weight based on the weight of the polycarbodiimide. % To 23% by weight, preferably 1% to 21% by weight, more preferably 5% to 19% by weight, more preferably 8% to 17% by weight, more preferably 10% to 15% by weight, and more preferably 11% by weight An NCO content in the range of% by weight to 13% by weight, wherein the NCO content is preferably determined according to DIN EN 1242.
41. The method according to the specific example 40, wherein 6 to 96 hours in (ii), preferably 8 to 72 hours, more preferably 10 to 48 hours, more preferably 12 to 36 hours, and more preferably 14 to 30 hours The NCO content is obtained after a reaction time of more preferably 16 to 24 hours, and more preferably 18 to 22 hours.
42. The method according to any one of the specific examples 1 to 41, wherein the polycarbodiimide obtained in (ii) has a value of 20 or less, preferably 10 or less, determined according to DIN 6162, and Better 5 or less color index.
43. The method according to any one of the specific examples 1 to 42, wherein the polymerization in (ii) is performed in batches.
44. The method according to any one of the specific examples 1 to 43, wherein the polymerization in (ii) is performed by reflux cooling.
45. The method according to any one of the specific examples 1 to 44, wherein in (ii), the polymerization is performed in the presence of an inert gas, wherein the inert gas is continuously introduced into the reaction mixture.
46. The method according to the specific example 45, wherein the inert gas has a flow rate in the range of 0.1 to 100 vol / hour, preferably 0.5 to 80 vol / hour, more preferably 1 to 50 vol / hour, more A flow rate in the range of preferably 5 to 40 vol / hr, more preferably 10 to 30 vol / hr, more preferably 15 to 25 vol / hr, and more preferably 18 to 22 vol / hr is introduced into the reaction mixture, where V represents The volume of the reaction mixture.
47. The method according to specific example 45 or 46, wherein the inert gas comprises one or more gases selected from the group consisting of: N ₂ , He, Ne, Ar, CO ₂ and mixtures thereof, the one or more gases Preferably selected from the group consisting of: N ₂ , Ar, CO ₂ and mixtures thereof, the one or more gases are more preferably selected from the group consisting of: N ₂ , CO ₂ and mixtures thereof, the inert gas used is more N ₂ or CO _{2 is} preferred, and N _{2 is} preferred.
48. The method according to any one of the specific examples 45 to 47, wherein the inert gas is passed through one or more immersion tubes, through a hole in a base and / or wall of the stirring tank, through a shaft of the agitator device And / or holes in the agitator and / or are introduced into the reaction mixture via an air ring, the inert gas is preferably introduced via an air ring, and the holes in the air ring are preferably partially and preferably fully pointed The base of the stirring tank.
49. The method according to the specific examples 45 to 48, wherein the stirrer device is provided with a hole in the shaft and / or the stirrer, preferably in the shaft and the stirrer, for introducing at least a part of the inert gas.
50. The method according to any of the specific examples 1 to 49, wherein in (ii) no gas and especially no inert gas is introduced into the reaction mixture.
51. The method of any one of specific examples 1 to 50, wherein the method further comprises (iii) separating the catalyst from the product mixture by distillation of the product mixture obtained in (ii) to obtain A first bottoms product and a first distillate, wherein the first bottoms product includes the polycarbodiimide and a portion of the catalyst, and the first distillate includes another portion of the catalyst,
(Iv) adding an air transport agent to the first bottom product obtained in (iii) to obtain a mixture, wherein the air transport agent has a lower boiling point than the polycarbodiimide,
(V) separating the catalyst from the mixture by distilling the mixture obtained in (iv) to obtain a second bottom product and a second distillate, wherein the second bottom product comprises the polycarbodiimide An amine and a portion of the catalyst, and the second distillate comprises another portion of the catalyst and the gas transport agent.
52. The method of embodiment 51, wherein the gas transport agent has a boiling point in the range of 150 to 350 ° C.
53. The method according to specific examples 51 or 52, wherein the gas transport agent does not have any amine group -NH- and / or -OH group and / or -SH group and / or -COOH group.
54. The method according to any one of the specific examples 51 to 53, wherein the gas transport agent comprises a diisocyanate, preferably the diisocyanate according to the specific example 29 or 30, wherein the gas transport agent is more preferably Or a plurality of diisocyanates, wherein the gas transporting agent is more preferably composed of a diisocyanate as described in specific examples 29 or 30.
55. The method according to any one of specific examples 51 to 54, wherein the distillation in (iii) and / or (v), preferably (iii) and (v) is at 100 to 400 ° C, preferably 130 It is carried out at a temperature in the range of 350 ° C and more preferably 150 to 250 ° C.
56. The method according to any one of the specific examples 51 to 55, wherein the pressure is in the range of 0.1 to 800 mbar, preferably 0.1 to 500 mbar, and more preferably 0.1 to 300 mbar (iii) And / or (v), preferably the distillation in (iii) and (v).
57. The method according to any one of specific examples 51 to 56, wherein (iv) and (v) are repeated, preferably 1 to 10 times, more preferably 1 to 7 times, more preferably 1 to 5 times, more 1 to 4 times better, 1 to 3 times better, 1 to 2 times better, and even better once.
58. The method according to any one of the specific examples 51 to 57, wherein the method further comprises (vi) making at least a part, preferably all, of the first distillate and / or the second distillate, and then Circulate to (i) for use in preparing the reaction mixture.
59. The method according to any one of the specific examples 1 to 58, wherein the polycarbodiimide is further reacted with a compound selected from the group consisting of a monohydric alcohol, a dihydric alcohol, a polyoxyalkylene alcohol , Monoamines and mixtures thereof, the compound is preferably selected from the group consisting of monohydric alcohols, glycols, polyethylene glycols, polypropylene glycols, monoamines and mixtures thereof.
60. A polycarbodiimide composition obtainable by and / or by a method as described in any one of specific examples 1 to 59.
61. The polycarbodiimide composition according to the specific example 60, wherein the polycarbodiimide composition has a content of 0.1% to 25% by weight, preferably 0.5% to 23% by weight, and preferably 1% by weight % To 21% by weight, more preferably 5% to 19% by weight, more preferably 8% to 17% by weight, more preferably 10% to 15% by weight and more preferably 11% to 13% by weight The NCO content is preferably determined according to DIN EN 1242.
62. The polycarbodiimide composition according to the specific example 60 or 61, wherein the polycarbodiimide composition has 20 or less, preferably 10 or less, and more preferably 5 according to DIN 6162. Or smaller color index.
Examples

All synthesis was performed in a 1000 ml flange flask using a stirrer and a reflux condenser. If an inert gas is used, nitrogen is used for this purpose, and the nitrogen is introduced through a steel pipe (immersion pipe) whose inner diameter is 3 mm lower than the liquid level. The amount of introduced gas is determined by means of a float meter. The vacuum generated by the rotary vane pump is applied at the upper outlet of the condenser.

The device was initially charged with 500 grams of 1,3-bis (1-isocyanato-1-methylethyl) benzene (TMXDI) and 1.2 grams of 1-methyl-2-phosphine 1-oxide And the equipment has the nitrogen flow rate specified in Table 1. At an internal temperature of 150 ° C, a vacuum of 300 mbar was applied. Different agitator forms are used in the examples, in which the reaction mixture is not transmitted axially (anchor agitator: comparative examples 1 and 2; disc stirrer: comparative examples 3 and 4), and according to the present invention, axial transmission Reaction mixture (inclined blade stirrer: Examples 1 to 4). For comparison with the effect of introducing nitrogen into the reaction mixture, the examples were carried out with and without introducing a gas.

The progress of the reaction was monitored by determining the NCO content, and the determination was performed according to DIN EN 1242. In each case, the reaction was carried out until the isocyanate content reached 12% by weight. Table 1 shows the results of examples using different agitators and performed with or without the introduction of nitrogen.

table 1 : Parameters and results of Examples 1 to 4 and Comparative Examples 1 to 4
(*) Transfer the reaction mixture towards the base of the stirred tank
(*) Transfer the reaction mixture away from the substrate of the stirring tank

Comparison of Examples 1 to 4 (agitator without axial transfer) with Examples 1 to 4 (agitated reaction mixture in axial direction) shows that the agitator with axial assembly achieves the reaction time unexpectedly The difference is reduced. This is particularly apparent by comparing Examples 1 and 2 with Example 1, where the reaction time is reduced by about 30%. As shown in other embodiments implemented with the introduction of an inert gas, it is possible to achieve a further reduction in reaction time by this.

As mentioned earlier, the disadvantage of introducing an inert gas is that it is a significant load on the exhaust system of the reactor. Therefore, a significant increase in the complexity of the equipment is required not only in supplying and feeding inert gas, but also in preventing the diisocyanate used as the starting compound from entering the environment. Therefore, compared with the prior art methods that work with introduction and gas, the preferred embodiment of the present invention implemented without the introduction of gas constitutes a better method because the polymerization reaction can be much less complicated In addition, the risk of environmental pollution caused by isocyanate escaping is significantly reduced. Therefore, in any case, compared with the prior art method of introducing an inert gas, these preferred specific examples are environmentally friendly alternatives for shortening the reaction time, and according to the prior art, the method for introducing inert gas is required. The additional equipment complexity to prevent the diisocyanate from escaping under gas, the preferred embodiment of the present invention that does not introduce an inert gas, although it is possible to have a longer reaction time, can be more cost effective.
Referenced prior art:
-US 4419294
-DE 4 318 979 A1
-WO 2014/044743 A
-US 2010/124147 A1
-Ian Torotwa et al. "A Study of the Mixing Performance of Different lmpeller Designs in Stirred Vessels Using Computational Fluid Dynamics" in Designs, Bd. 2, Nr. 10, 8. Marz 2018 (2018-03-08), Seiten 1- 16

no

no

Claims (15)

A method for preparing polycarbodiimide, comprising (I) preparing a reaction mixture comprising a diisocyanate and a catalyst, and (Ii) polymerizing the diisocyanate in a stirred tank by heating the reaction mixture prepared in (i) to a temperature in the range of 20 to 250 ° C. under a pressure in the range of 20 to 800 mbar; Polycarbodiimide, wherein agitator equipment is used to agitate the reaction mixture during the polymerization, The method includes axially transferring the reaction mixture to the axis of rotation of the stirring operation by means of the stirring operation. The method according to claim 1, wherein in (ii), the reaction mixture is heated to a temperature ranging from 40 to 230 ° C. Process according to claim 1 or 2, wherein in (ii) the reaction mixture is heated at a pressure in the range of 50 to 750 mbar. The method of any one of claims 1 to 3, wherein in (ii), the reaction mixture is heated at the temperature for a duration of 6 to 96 hours. The method according to any one of claims 1 to 4, wherein the agitator device consists of one or more axially conveyed agitators. The method according to claim 5, wherein the agitator has a circulation coefficient k _{z in a} range of 0.05 to 5. The method according to any one of claims 1 to 6, wherein the fluid volume of the reaction mixture is in the range of 0.5 to 50 cubic meters. The method according to any one of claims 1 to 7, wherein the agitator device is composed of one or more agitators selected from the group consisting of: propeller agitator, inclined blade agitator, Archimedes agitation Mixer, MIG mixer and cross anchor mixer. The method according to any one of claims 1 to 8, wherein the diisocyanate has the formula R (NCO) ₂ , wherein R is selected from the group consisting of a linear or branched C ₃ -C ₁₅ alkyl group, a ring aliphatic C ₅ -C ₂₀ alkyl, C ₆ -C ₁₈ aryl, C ₇ -C ₂₀ aralkyl and C ₇ -C ₂₀ alkylaryl group. The method according to any one of claims 1 to 9, wherein the diisocyanate is selected from the group consisting of: methylene diisocyanate, dimethyl methylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate Isocyanate, pentyl diisocyanate, dipropyl ether diisocyanate, 1,5-diisocyanate-2,2-dimethylpentane, 1,6-diisocyanate-3-methoxyhexane, Octamethylene diisocyanate, 1,5-diisocyanate-2,2,4-trimethylpentane, hexamethylene diisocyanate, decamethylene diisocyanate, 1,6-diisocyanate 3-butoxyhexane, 1,4-butanediol dipropyl ether diisocyanate, thiodihexyl diisocyanate, m-xylene diisocyanate, xylene diisocyanate, isophorone diisocyanate, di Cyclohexylmethane 4,4'-diisocyanate, 1,3-bis (1-isocyanato-1-methylethyl) benzene, toluene 2,4-diisocyanate, diphenylmethane 2,2'- Diisocyanate, diphenylmethane 2,4'-diisocyanate and diphenylmethane 4,4'-diisocyanate, hexamethylene 1,6-diisocyanate and 1,12-diisocyanate dodecane, and Its mixture. The method of any one of claims 1 to 10, wherein the catalyst comprises one or more organophosphorus compounds. The method of claim 11, wherein the one or more organophosphorus compounds comprise one or more phosphin oxides of formula (I) Wherein R ¹ and R ^{2 are} independently H or optionally substituted aliphatic C ₁ -C ₁₅ alkyl, cycloaliphatic C ₅ -C ₁₅ alkyl, C ₆ -C ₁₅ aryl, C ₇ -C ₁₅ Aralkyl or C ₇ -C ₁₅ alkylaryl. The method according to any one of claims 1 to 12, wherein in (ii) the polymerization is performed in the presence of an inert gas, wherein the inert gas is continuously introduced into the reaction mixture. The method of any one of claims 1 to 13, wherein the method further comprises (Iii) separating the catalyst from the product mixture by distilling the product mixture obtained in (ii) to obtain a first bottom product and a first distillate, wherein the first bottom product comprises the polycarbodicarbonate Imine and a part of the catalyst, and the first distillate comprises another part of the catalyst, (Iv) adding an air transport agent to the first bottom product obtained in (iii) to obtain a mixture, wherein the air transport agent has a lower boiling point than the polycarbodiimide, (V) separating the catalyst from the mixture by distilling the mixture obtained in (iv) to obtain a second bottom product and a second distillate, wherein the second bottom product comprises the polycarbodiimide An amine and a portion of the catalyst, and the second distillate comprises another portion of the catalyst and the gas transport agent. A polycarbodiimide composition obtainable by and / or by a method according to any one of claims 1 to 14.