ANIONIC POLYMERISATION OF LACTAMS

Abstract

Provided herein is a process for producing a polyamide (P) by reaction of a mixture (M) including at least one lactam (component (A)), at least one catalyst (component (B)), at least one activator (component (C)), and at least one oxazolidine derivative (component (D)). Further provided herein is the mixture (M) and the use of an oxazolidine derivative for increasing the crystallization rate of a polyamide (P). Also provided herein is the use of an oxazolidine derivative in a polyamide (P) for producing a molded article from the polyamide (P) for reducing the demolding time of the molded article and the use of an oxazolidine derivative for removing water from a reaction mixture (RM).

Claims

1. A process for producing a polyamide (P) by reacting a mixture (M), the mixture (M) comprising the components: (A) at least one lactam, (B) at least one catalyst selected from the group consisting of alkali metal lactamates, alkaline earth metal lactamates, alkali metals, alkaline earth metals, alkali metal hydrides, alkaline earth metal hydrides, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal alkoxides, alkaline earth metal alkoxides, alkali metal amides, alkaline earth metal amides, alkali metal oxides, alkaline earth metal oxides, and organometallic compounds, (C) at least one activator selected from the group consisting of carbodiimides, isocyanates, acid anhydrides, acid halides, and the reaction products thereof with the component (A), (D) at least one oxazolidine derivative selected from the group consisting of 3-(1,3 -oxazolidine)ethanol-2-(1-methylethyl)-3,3-carbonate and 3-butyl-2-(1-ethylpentyl)-1,3-oxazolidine.

2. The process according to claim 1, wherein the component (A) present in the mixture (M) has a melting point T.sub.M(A) , and wherein the reaction of the mixture (M) takes place at a temperature T greater than the melting point T.sub.M(A) of the component (A).

3. The process according to claim 1, wherein the polyamide (P) has a melting point T.sub.M(P), and wherein the reaction of the mixture (M) takes place at a temperature T less than the melting point T.sub.M(P) of the polyamide (P).

4. The process according to claim 1, wherein the component (A) present in the mixture (M) is at least one lactam comprising 4 to 12 carbon atoms.

5. The process according to claim 1, wherein the component (A) present in the mixture (M) is selected from the group consisting of pyrrolidone, piperidone, -caprolactam, enantholactam, caprylolactam, capriclactam, and laurolactam.

6. The process according to claim 1, wherein the mixture (M) comprises from 75 to 99.7 wt % of the component (A), from 0.1 to 5 wt % of the component (B), from 0.1 to 10 wt % of the component (C) and from 0.1 to 10 wt % of the component (D) based on the total weight of the mixture (M).

7. A mixture (M) comprising the components: (A) at least one lactam, (B) at least one catalyst selected from the group consisting of alkali metal lactamates, alkaline earth metal lactamates, alkali metals, alkaline earth metals, alkali metal hydrides, alkaline earth metal hydrides, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal alkoxides, alkaline earth metal alkoxides, alkali metal amides, alkaline earth metal amides, alkali metal oxides, alkaline earth metal oxides, and organometallic compounds, (C) at least one activator selected from the group consisting of carbodiimides, isocyanates, acid anhydrides, acid halides and the reaction products thereof with the component (A), (D) at least one oxazolidine derivative selected from the group consisting of 3-(1,3-oxazolidine)ethanol-2-(1-methylethyl)-3,3-carbonate and 3-butyl-2-(1-ethylpentyl)-1,3-oxazolidine.

8. A method for increasing the crystallization rate of a polyamide (P) using an oxazolidine derivative in the polyamide (P) wherein the oxazolidine derivative is selected from the group consisting of 3-(1,3-oxazolidine)ethanol-2-(1-methylethyl)-3,3-carbonate and 3-butyl-2-(1-ethylpentyl)-1,3-oxazolidine.

9. A method for producing a molded article from a polyamide (P) for reducing a demolding time of the molded article, wherein at least one oxazolidine derivative in the polyimide (P) is selected from the group consisting of 3-(1,3-oxazolidine)ethanol-2-(1-methylethyl)-3,3-carbonate and 3-butyl-2-(1-ethylpentyl)-1,3-oxazolidine.

10. A method for removing water from a reaction mixture (RM) using an oxazolidine derivative in the reaction mixture (RM), the reaction mixture (RM) comprising the components: (A) at least one lactam, (B) at least one catalyst selected from the group consisting of alkali metal lactamates, alkaline earth metal lactamates, alkali metals, alkaline earth metals, alkali metal hydrides, alkaline earth metal hydrides, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal alkoxides, alkaline earth metal alkoxides, alkali metal amides, alkaline earth metal amides, alkali metal oxides, alkaline earth metal oxides, and organometallic compounds, (C) at least one activator selected from the group consisting of carbodiimides, isocyanates, acid anhydrides, acid halides, and the reaction products thereof with the component (A), (D) at least one oxazolidine derivative selected from the group consisting of 3-(1,3-oxazolidine)ethanol-2-(1-methylethyl)-3,3-carbonate and 3-butyl-2-(1-ethylpentyl)-1,3-oxazolidine, and (E) water.

11.-15. (canceled)

Description

[0294] FIG. 1a shows the effect of Incozol 2 as the oxazolidine derivative on the reactivity of the mixture (M). FIG. 1b shows the effect of Incozol LV as the oxazolidine derivative on the reactivity of the mixture (M). The X-axes denote time t in seconds (s) and the Y axes denote temperature T in C. The reaction of the mixture (M) is exothermic. Thus energy is released during the reaction of the mixture (M) and the mixture (M) heats up during the reaction. To determine the reactivity the temperature T of the mixture (M) was measured as a function of time t. The starting point t.sub.Start (0 s) was the point in time at which the mixture (M) was available and had a temperature T of 140 C. The more rapid the change in the temperature T of the mixture (M), the more rapid the reaction of the mixture (M) and the higher the reactivity of the mixture (M).

[0295] It is apparent from figure la that the addition of Incozol 2 as the oxazolidine derivative increases the reactivity of the mixture (M), i.e. that the temperature T of the mixture (M) changes more rapidly than without the addition of Incozol 2 as the oxazolidine derivative (comparative example V1).

[0296] It is apparent from FIG. 1b that as a result of the addition of Incozol LV as the oxazolidine derivative the reactivity of the mixture (M) is similar to the reactivity of the mixture without addition of Incozol LV as the oxazolidine derivative (comparative example V1). In addition, the reaction proceeds in a similarly exothermic fashion as the reaction of the mixture without Incozol LV as the oxazolidine derivative.

[0297] FIG. 2a shows the time to crystal formation as a function of the amount of Incozol 2 as the oxazolidine derivative present in the mixture (M). The X-axis represents the amount of Incozol 2 present in the mixture (M) in mol % and the Y-axis shows the time t in seconds (s) between the provision of the mixture (M) at 140 C. and the becoming apparent of a clouding of the mixture (M). It is apparent from FIG. 2a that with increasing proportion of Incozol 2 as the oxazolidine derivative the time until onset of clouding and thus until commencement of crystal formation is markedly reduced.

[0298] FIG. 2b shows the time to crystal formation as a function of the amount of Incozol LV as the oxazolidine derivative present in the mixture (M). The X-axis represents the amount of Incozol LV present in the mixture (M) in mol % and the Y-axis shows the time t in seconds (s) between the provision of the mixture (M) at 140 C. and the becoming apparent of a clouding of the mixture (M). It is apparent from FIG. 2b that with increasing proportion of Incozol LV as the oxazolidine derivative the time until onset of clouding and thus until commencement of crystal formation is likewise markedly reduced.

[0299] FIG. 3a shows the demolding time for different contents of Incozol 2 as the oxazolidine derivative in the mixture (M). The X-axis represents the proportion of oxazolidine derivative in the mixture (M) in mol % and the Y-axis represents the time tin minutes (min). To determine the demolding time the point in time t.sub.demstart at which the polyamide (P) produced during the reaction of the mixture (M) begins to detach from the wall of the reactor was determined. As soon as the polyamide (P) produced during the reaction of the mixture (M) stops shrinking, the point in time t.sub.demend is reached. The points in time t.sub.demstart and t.sub.demend are shown in FIG. 3a as a function of the Incozol 2 proportion. The difference between the two points in time is the demolding time. It is apparent that the demolding time is reduced by the oxazolidone derivative.

[0300] FIG. 3b shows the demolding time for different contents of Incozol LV as the oxazolidine derivative in the mixture (M). The X-axis represents the proportion of oxazolidine derivative in the mixture (M) in mol % and the Y-axis represents the time tin minutes (min). To determine the demolding time the point in time t.sub.demstart at which the polyamide (P) produced in the reaction of the mixture (M) begins to detach from the wall of the reactor was determined. As soon as the polyamide (P) produced during the reaction of the mixture (M) stops shrinking, the point in time t.sub.demend is reached. The points in time t.sub.demstart and t.sub.demend are shown in FIG. 3b as a function of the Incozol LV proportion. The difference between the two points in time is the demolding time. It is apparent that the demolding time is reduced by the oxazolidine derivative.

[0301] FIGS. 4 and 5 show how the reactivity of a reaction mixture (RM) comprising 350 ppm (FIG. 4) and 700 ppm (FIG. 5) of water is changed by the presence of Incozol 2 as the oxazolidinone derivative. The X-axes in each case show the time t in seconds (s) and the Y-axes show the temperature T of the reaction mixture (RM). It is apparent from the gradient of the curve that the reactivity is highest when dry caprolactam is used (comparative example V1) and lowest when caprolactam having a water content of 350 ppm (comparative example V13) and of 700 ppm (comparative example V20) is used. The use of Incozol 2 as the oxazolidinone derivative increases the reactivity compared to the use of caprolactam having a water content of 350 ppm (comparative example V13) and of 700 ppm (comparative example V20) without oxazolidine derivative.

[0302] FIG. 6 shows how the reactivity of the reaction mixture (RM) comprising 530 ppm of water is changed by the presence of Incozol LV as the oxazolidine derivative. The X-axis shows the time t in seconds (s) and the Y-axis shows the temperature T of the reaction mixture (RM). It is apparent from the gradient of the curves that the reactivity is highest when dry caprolactam is used (comparative example V1) and lowest when caprolactam having a water content of 530 ppm (comparative example V27) is used. The use of Incozol LV as the oxazolidinone derivative increases the reactivity compared to the use of caprolactam having a water content of 530 ppm (comparative example V27) without oxazolidine derivative.

[0303] FIG. 7 shows the residual content of caprolactam (proportion of unreacted component (A)) in the produced polyamide (P) as a function of the employed amount of Incozol 2 as the oxazolidine derivative for different proportions of water in the employed caprolactam (component (A)). The X-axis represents the employed amount of oxazolidine derivative in mol % and the Y-axis the residual content of caprolactam in wt % based on the total weight of the polyamide (P). It is apparent that the residual content of caprolactam can be reduced with increasing proportion of oxazolidine derivative.