Core-shell polyamide powder

Abstract

The invention relates to a seeded particle of polyamide (PA) powder composed of a shell made of PA-6, PA-12 or PA-6/12 and of a core made from PA-6, paA-11, PA-12 or PA-6/12, PA 6,12, PA-6,6, PA-8 or PA-4, the core and the shell being either of identical polyamide nature but of different molecular weight, or of different polyamide nature. The particle for which the shell has a melting temperature Tf1 and a crystallization temperature Tc1 and for which the core has a melting temperature Tf2 and a crystallization temperature Tc2, is characterized in that the difference in absolute value between Tf1Tc1 and/or between Tf2Tc2 is greater than the difference in absolute values between the melting temperature and the crystallization temperature of a particle of powder seeded by a mineral filler and for which the shell is made of PA6, PA12 or PA6/12.

Claims

1. A seeded polyamide (PA) powder particle comprising a shell of polyamide and a core of polyamide, the core and the shell being either of identical polyamide type but of different molecular mass, or of different polyamide type, wherein the seeded polyamide is obtained by polymerization of amide monomer in the presence of a polyamide seed, and the shell is PA6, PA12 or PA6/12 and the core is PA6, PA11, PA12, PA6/12, PA6,6, PA8 or PA4, and wherein said shell has a melting temperature Tf1 and a crystallization temperature Tc1 and said core has a melting temperature Tf2 and a crystallization temperature Tc2, Tf1, Tc1, Tf2 and Tc2 are such that the difference in absolute value between Tf1Tc1 and/or between Tf2Tc2 of said seeded polyamide powder is greater than the difference in absolute value between the melting temperature and the crystallization temperature of a powder particle seeded by silica and having a shell of PA6, PA12 or PA6/12.

2. The particle of claim 1, having a shell of PA6 and a core that is PA11, PA12, PA6/12, PA6,12, PA6,6, PA8, or PA4.

3. The particle of claim 1, having a shell of PA12 and a core that is PA6, PA11, PA6/12, PA6,12, PA6,6, PA8, or PA4.

4. The particle of claim 1, having a shell of PA6/12 and a core that is PA6, PA11, PA12, PA6,12, PA6,6, PA8, or PA4.

5. The particle of claim 1, comprising a shell of polyamide and a core of polyamide, the core and the shell being either of identical polyamide type but of different molecular mass, or of different polyamide type, wherein the shell consists of PA6, PA12 or PA6/12, and the core consists of PA6, PA11, PA12, PA6/12, PA6,12, PA6,6, PA8 or PA4.

6. The particle of claim 1, wherein the core consists of polyamide.

7. A process for preparing a powder particle comprising a shell of polyamide and a core of polyamide according to claim 1, the core and shell being of different polyamide type, comprising anionic polymerization in solution in a solvent, of lactam 6, of lactam 12 or of a mixture thereof, in the presence of a catalyst, an activator, at least one N,N-alkylenebisamide, and an organic filler, wherein the organic filler is PA6, PA11, PA12, PA6/12, PA6,12, PA6,6, PA8 or PA4.

8. The process of claim 7, wherein the N,N-alkylenebisamide is N,N-Ethylenebisstearamide (EBS) or N,N-Ethylenebisoleamide (EBO).

9. The process of claim 8, comprising the presence, in addition to the N,N-alkylenebisamide, of an amide selected from the group consisting of oleamide, N-stear-amide, isostearamide, and erucamide.

10. A composite, substrate coating, transfer paper or cosmetic composition, comprising a particle of claim 1.

11. An article manufactured by sintering one or more of the particles of claim 1 by melting induced by radiation from a laser beam, infrared radiation or UV radiation.

12. A method of producing an article according to claim 11, by sintering of powder particles composed of a shell of polyamide and a core of polyamide, the core and shell being of different polyamide type, comprising a) placing a layer of powder (layer 1) on a horizontal plate held in a chamber heated to a temperature between the crystallization temperature (Tc) and the melting temperature (TO of said powder, b) sintering the powder particles at different points of the powder layer (layer 1) with a laser according to a geometry corresponding to the geometry at layer 1 of an article to be produced, c) lowering the horizontal plate by a value corresponding to the thickness of one layer of powder and then a new layer of powder (layer 2) is deposited, d) sintering the powder particles of the powder layer (layer 2) with the laser according to a geometry corresponding to the geometry at layer 2 of the article to be produced, e) lowering the horizontal plate by a value corresponding to the thickness of one layer of powder and then a new layer of powder is deposited, f) sintering the powder particles of the powder layer with the laser according to a geometry corresponding to the geometry at the layer deposited in step e) of an article to be produced, g) repeating the above steps e) and f) until the article is finished; h) gradually lowering the temperature to below the crystallization temperature (Tc); and i) separating, after complete cooling, the article from remaining powder.

Description

(1) THE EXAMPLES

(2) We are now going to give examples of the invention (see tables 1 and 2 below).

(3) Measurement of the Particle Size of the Powders Obtained

(4) The powders obtained in the inventive and comparative examples below are analyzed using a Coulter LS230 granulometer. It allows the particle-size distribution of the powders to be obtained, from which it is possible to determine: % The average diameter. % The breadth of the distribution or the standard deviation of the distribution.

(5) The particle-size distribution of the powders according to the invention is determined by the customary techniques, using a Coulter LS230 granulometer from Beckman-Coulter. From the particle-size distribution it is possible to ascertain the volume-average diameter with the logarithmic calculation mode, version 2.11a. of the software, and also the standard deviation, which measures the narrowness of the distribution or the breadth of the distribution around the average diameter. One of the advantages of the process described here is that it allows a narrow distribution (low standard deviation) to be obtained in relation to the average diameter. This standard deviation is calculated using the logarithmic statistical calculation mode, version 2.11a. of the software.

(6) Measurement of the Thermal Characteristics by DSC

(7) The powders are analyzed in accordance with the standard ISO 11357-3 PlasticsDifferential scanning calorimetry (DSC) Part 3: Determination of temperature and enthalpy of melting and crystallization.

(8) In the examples below, particularly with regard to the DSC, the melting temperature indicated by Tf corresponds to the first heating or melting temperature Tf1.

(9) Measurement of the Solution Viscosity

(10) The solution viscosity is measured at 0.5% by mass in m-cresol at 20 C. Since the solution viscosity is related to the molecular mass, the viscosity is a means of expressing the molecular mass.

EXAMPLES

Tables 1 and 2 Below

Comparative Example 1

PA6/12+Silica

(11) The reactor, maintained under nitrogen, is charged with 2800 ml of solvent and then, in succession, with 108 g of caprolactam, 791 g of dry lauryllactam, 14.4 g of EBS, and 12.6 g of finely divided AEROSIL R972 (silica). After the stirring has been commenced at 300 rpm, heating is carried out gradually to 110 C., and then 290 ml of solvent are distilled off under vacuum in order, azeotropically, to entrain any trace of water that might be present.

(12) Following a return to atmospheric pressure, the anionic catalyst and 7.2 g of sodium hydride at 60% purity in oil are introduced rapidly under nitrogen, and the stirring is increased to 720 rpm, under nitrogen at 110 C. for 30 minutes.

(13) Subsequently the temperature is taken to 96 C. and, using a small metering pump, the selected activator, namely stearyl isocyanate (32.9 g made up to 314 g with the solvent), is injected continuously into the reaction mixture in accordance with the following program: % 10 g/h of isocyanate solution for 300 minutes; % 88 g/h of isocyanate solution for 180 minutes;

(14) In parallel the temperature is maintained at 96 C. for the first 360 minutes and then is raised to 110 C. over 60 minutes and held at 110 C. for a further 2 hours after the end of introduction of the isocyanate. The polymerization is then at an end and the reactor is almost clean.

(15) After cooling to 80 C., decanting, and drying, the particle size is between 1 and 40 m, with an average particle diameter of 9.9 m, a standard deviation of 1.54, and an ASSA of 16.8 m.sup.2/g without agglomerates. The first melting point is 163 C. and the solution viscosity is 0.84 dl/g.

Inventive Example 2

PA6/12 Seeded with PA12

(16) The reactor, maintained under nitrogen, is charged with 2800 ml of solvent and then, in succession, with 108 g of caprolactam, 679 g of dry lauryllactam, 14.4 g of EBS, and 112 g of finely divided ORGASOL 2001 UD NAT1 (PA12 powder 5 m in diameter). After the stirring has been commenced at 300 rpm, heating is carried out gradually to 110 C., and then 290 ml of solvent are distilled off under vacuum in order, azeotropically, to entrain any trace of water that might be present.

(17) Following a return to atmospheric pressure, the anionic catalyst and 7.2 g of sodium hydride at 60% purity in oil are introduced rapidly under nitrogen, and the stirring is increased to 720 rpm, under nitrogen at 110 C. for 30 minutes.

(18) Subsequently the temperature is taken to 96 C. and, using a small metering pump, the selected activator, namely stearyl isocyanate (32.9 g made up to 314 g with the solvent), is injected continuously into the reaction mixture in accordance with the following program: % 10 g/h of isocyanate solution for 300 minutes; % 88 g/h of isocyanate solution for 180 minutes;

(19) In parallel the temperature is maintained at 96 C. for the first 360 minutes and then is raised to 110 C. over 60 minutes and held at 110 C. for a further 2 hours after the end of introduction of the isocyanate.

(20) The polymerization is at an end and the reactor is almost clean. After cooling to 80 C., decanting, and drying, the particle size is between 3 and 35 m, with an average particle diameter of 11.8 m, a standard deviation of 1.27, and an ASSA of 9.3 m.sup.2/g without agglomerates. The shell and core melting temperatures are 161.5 C. and 173.7 C. respectively.

Comparative Example 3

PA6/12+Silica

(21) The reactor, maintained under nitrogen, is charged with 2800 ml of solvent and then, in succession, with 108 g of caprolactam, 791 g of dry lauryllactam, 24.7 g of EBS, and 16.2 g of finely divided AEROSIL R972 (silica). After the stirring has been commenced at 300 rpm, heating is carried out gradually to 110 C., and then 290 ml of solvent are distilled off under vacuum in order, azeotropically, to entrain any trace of water that might be present.

(22) Following a return to atmospheric pressure, the anionic catalyst and 7.2 g of sodium hydride at 60% purity in oil are introduced rapidly under nitrogen, and the stirring is increased to 720 rpm, under nitrogen at 110 C. for 30 minutes.

(23) Subsequently the temperature is taken to 105 C. and, using a small metering pump, the selected activator, namely stearyl isocyanate (32.9 g made up to 324 g with the solvent), is injected continuously into the reaction mixture in accordance with the following program: % 53.9 g/h of isocyanate solution for 360 minutes;

(24) In parallel the temperature is maintained at 105 C. for the 360 minutes of injection and then is raised to 110 C. over 60 minutes and held at 110 C. for a further 3 hours after the end of introduction of the isocyanate.

(25) The polymerization is at an end and the reactor is almost clean. After cooling to 80 C., decanting, and drying, the particle size is between 2 and 70 m, with an average particle diameter of 23.8 m and a standard deviation of 1.65 without agglomerates.

Inventive Example 4

PA6/12 Seeded with PA12

(26) The reactor, maintained under nitrogen, is charged with 2800 ml of solvent and then, in succession, with 108 g of caprolactam, 791 g of dry lauryllactam, 12.6 g of EBS, and 18.7 g of finely divided ORGASOL 2001 UD NAT1 (PA12 powder 5 m in diameter). After the stirring has been commenced at 300 rpm, heating is carried out gradually to 110 C., and then 290 ml of solvent are distilled off under vacuum in order, azeotropically, to entrain any trace of water that might be present.

(27) Following a return to atmospheric pressure, the anionic catalyst and 5.4 g of sodium hydride at 60% purity in oil are introduced rapidly under nitrogen, and the stirring is increased to 720 rpm, under nitrogen at 110 C. for 30 minutes.

(28) Subsequently the temperature is taken to 96 C. and, using a small metering pump, the selected activator, namely stearyl isocyanate (16.45 g made up to 324 g with the solvent), is injected continuously into the reaction mixture in accordance with the following program: % 53.9 g/h of isocyanate solution for 360 minutes;

(29) In parallel the temperature is maintained at 96 C. for 360 minutes during injection and then is raised to 110 C. over 60 minutes and held at 110 C. for a further 3 hours after the end of introduction of the isocyanate.

(30) The polymerization is at an end and the reactor is almost clean. After cooling to 80 C., decanting, and drying, the particle size is between 1 and 40 m, with an average particle diameter of 18.8 m, the solution viscosity is 0.91 dl/g, and Tf1=166.9 C. and Tc1=109.2 C.

Inventive Example 5

PA6 Seeded with PA12

(31) The reactor, maintained under nitrogen, is charged with 2800 ml of solvent and then, in succession, with 899 g of caprolactam, 7.2 g of EBS, and 54 g of ORGASOL 2001 EXD NAT1. After the stirring has been commenced at 300 rpm, heating is carried out gradually to 110 C., and then 290 ml of solvent are distilled off under vacuum in order, azeotropically, to entrain any trace of water that might be present.

(32) Following a return to atmospheric pressure, the anionic catalyst and 5.8 g of sodium hydride at 60% purity in oil are introduced rapidly under nitrogen, and the stirring is increased to 550 rpm, under nitrogen at 110 C. for 30 minutes.

(33) Subsequently the temperature is taken to 120 C. and this temperature is maintained for 60 minutes. Using a small metering pump, the selected activator, namely stearyl isocyanate (37.3 g made up to 66.3 g with the solvent), is injected continuously into the reaction mixture in accordance with the following program: % 41 g/h of isocyanate solution for 95 minutes.

(34) In parallel the temperature is maintained at 120 C. for the first 215 minutes.

(35) The polymerization is at an end and the reactor is almost clean. After cooling to 80 C., decanting, and drying, the particle size is between 10 and 80 m, with an average particle diameter of 31 m.

(36) DSC analysis shows Tf=171 C., Tf=216 C., Tc=144 C., and Tc=176 C.

Inventive Example 6

PA6 Seeded with PA6

(37) The reactor, maintained under nitrogen, is charged with 2800 ml of solvent and then, in succession, with 899 g of caprolactam, 7.2 g of EBS, and 54 g of ORGASOL 1002 D NAT1 (PA6 powder). After the stirring has been commenced at 300 rpm, heating is carried out gradually to 110 C., and then 290 ml of solvent are distilled off under vacuum in order, azeotropically, to entrain any trace of water that might be present.

(38) Following a return to atmospheric pressure, the anionic catalyst and 5.8 g of sodium hydride at 60% purity in oil are introduced rapidly under nitrogen, and the stirring is increased to 550 rpm, under nitrogen at 110 C. for 30 minutes.

(39) Subsequently the temperature is taken to 120 C. and this temperature is maintained for 60 minutes. Using a small metering pump, the selected activator, namely stearyl isocyanate (37.3 g made up to 66.3 g with the solvent), is injected continuously into the reaction mixture in accordance with the following program: % 41 g/h of isocyanate solution for 95 minutes.

(40) In parallel the temperature is maintained at 120 C. for the first 215 minutes.

(41) The polymerization is at an end and the reactor is almost clean. After cooling to 80 C., decanting, and drying, the particle size is between 10 and 100 m, with an average particle diameter of 45.8 m. DSC analysis shows Tf=214 C. and Tc=172 C.

Comparative Example 7

PA6+Silica

(42) The reactor, maintained under nitrogen, is charged with 2800 ml of solvent and then, in succession, with 899 g of caprolactam, 7.2 g of EBS, and 5.75 g of finely divided AEROSIL 8972 (silica). After the stirring has been commenced at 300 rpm, heating is carried out gradually to 110 C., and then 290 ml of solvent are distilled off under vacuum in order, azeotropically, to entrain any trace of water that might be present.

(43) Following a return to atmospheric pressure, the anionic catalyst and 5.8 g of sodium hydride at 60% purity in oil are introduced rapidly under nitrogen, and the stirring is increased to 550 rpm, under nitrogen at 110 C. for 30 minutes.

(44) Subsequently the temperature is taken to 120 C. and this temperature is maintained for 60 minutes. Using a small metering pump, the selected activator, namely stearyl isocyanate (37.3 g made up to 66.3 g with the solvent), is injected continuously into the reaction mixture in accordance with the following program: % 41 g/h of isocyanate solution for 95 minutes.

(45) In parallel the temperature is maintained at 120 C. for the first 215 minutes.

(46) The polymerization is at an end and the reactor is almost clean. After cooling to 80 C., decanting, and drying, the particle size is between 2 and 75 m, with an average particle diameter of 23 m. DSC analysis shows Tf=216 C. and Tc=179 C.

Comparative Example 8

PA12+Silica

(47) The reactor, maintained under nitrogen, is charged with 2757 ml of solvent and then, in succession, with 899 g of lactam12, 7.2 g of EBS, and 7.5 g of Sipernat 320DS silica. After the stirring has been commenced at 300 rpm, heating is carried out gradually to 105 C., and then 360 ml of solvent are distilled off under vacuum in order, azeotropically, to entrain any trace of water that might be present.

(48) Following a return to atmospheric pressure, the anionic catalyst and 2.7 g of sodium hydride at 60% purity in oil are introduced rapidly under nitrogen, and the stirring is increased to 550 rpm, under nitrogen at 105 C. for 30 minutes.

(49) Using a small metering pump, the selected activator, namely stearyl isocyanate (19.2 g made up to 220.5 g with the solvent), is injected continuously into the reaction mixture in accordance with the following program: % 8 g/h of isocyanate solution for 180 minutes % 26 g/h of isocyanate solution for 120 minutes % 71 g/h of isocyanate solution for 120 minutes

(50) In parallel the temperature is maintained at 105 C. for 360 minutes during injection and then is raised to 110 C. over 30 minutes and held at 110 C. for 30 minutes and then is raised to 130 min in 30 min and maintained at 130 min for a further 3 hours after the end of introduction of the isocyanate.

(51) The polymerization is at an end and the reactor is almost clean. After cooling to 80 C., decanting, and drying, the particle size is between 15 and 80 m, with an average particle diameter of 36 m. DSC analysis shows Tf=183 C. and Tc=138.2 C.

Inventive Example 9

PA12 Seeded with PA12

(52) The reactor, maintained under nitrogen, is charged with 2757 ml of solvent and then, in succession, with 899 g of lactam12, 7.2 g of EBS, and 11.3 g of Orgasol 2001 EXD NAT1 (PA12 powder). After the stirring has been commenced at 300 rpm, heating is carried out gradually to 105 C., and then 360 ml of solvent are distilled off under vacuum in order, azeotropically, to entrain any trace of water that might be present.

(53) Following a return to atmospheric pressure, the anionic catalyst and 2.7 g of sodium hydride at 60% purity in oil are introduced rapidly under nitrogen, and the stirring is increased to 550 rpm, under nitrogen at 105 C. for 30 minutes.

(54) Using a small metering pump, the selected activator, namely stearyl isocyanate (19.2 g made up to 220.5 g with the solvent), is injected continuously into the reaction mixture in accordance with the following program: % 8 g/h of isocyanate solution for 180 minutes % 26 g/h of isocyanate solution for 120 minutes % 71 g/h of isocyanate solution for 120 minutes

(55) In parallel the temperature is maintained at 105 C. for 360 minutes during injection and then is raised to 110 C. over 30 minutes and held at 110 C. for 30 minutes and then is raised to 130 min in 30 min and maintained at 130 min for a further 3 hours after the end of introduction of the isocyanate.

(56) The polymerization is at an end and the reactor is almost clean. After cooling to 80 C., decanting, and drying, the particle size is between 20 and 90 m, with an average particle diameter of 50 m. DSC analysis shows Tf=183.8 C. and Tc=134.7 C.

Inventive Example 10

PA12 Seeded with PA12

(57) The reactor, maintained under nitrogen, is charged with 2757 ml of solvent and then, in succession, with 899 g of lactam12, 7.2 g of EBS, and 1.65 g of Orgasol 2002 UD NAT1 (PA12 powder). After the stirring has been commenced at 300 rpm, heating is carried out gradually to 105 C., and then 360 ml of solvent are distilled off under vacuum in order, azeotropically, to entrain any trace of water that might be present.

(58) Following a return to atmospheric pressure, the anionic catalyst and 2.7 g of sodium hydride at 60% purity in oil are introduced rapidly under nitrogen, and the stirring is increased to 550 rpm, under nitrogen at 105 C. for 30 minutes.

(59) Using a small metering pump, the selected activator, namely stearyl isocyanate (19.2 g made up to 220.5 g with the solvent), is injected continuously into the reaction mixture in accordance with the following program: % 8 g/h of isocyanate solution for 180 minutes % 26 g/h of isocyanate solution for 120 minutes % 71 g/h of isocyanate solution for 120 minutes

(60) In parallel the temperature is maintained at 105 C. for 360 minutes during injection and then is raised to 110 C. over 30 minutes and held at 110 C. for 30 minutes and then is raised to 130 min in 30 min and maintained at 130 min for a further 3 hours after the end of introduction of the isocyanate.

(61) The polymerization is at an end and the reactor is almost clean. After cooling to 80 C., decanting, and drying, the particle size is between 20 and 90 m, with an average particle diameter of 46 m. DSC analysis shows Tf=183 C. and Tc=135.8 C.

Comparative Example 11

PA6/12+Silica

(62) The reactor, maintained under nitrogen, is charged with 2800 ml of solvent and then, in succession, with 323 g of caprolactam, 575 g of lactam12, 30.9 g of EBS, and 10.8 g of finely divided AEROSIL R972 (silica). After the stirring has been commenced at 300 rpm, heating is carried out gradually to 110 C., and then 290 ml of solvent are distilled off under vacuum in order, azeotropically, to entrain any trace of water that might be present.

(63) Following a return to atmospheric pressure, the anionic catalyst and 9 g of sodium hydride at 60% purity in oil are introduced rapidly under nitrogen, and the stirring is increased to 550 rpm, under nitrogen at 110 C. for 30 minutes.

(64) Subsequently the temperature is taken to 81 C. and this temperature is maintained for 30 minutes. Using a small metering pump, the selected activator, namely stearyl isocyanate (32.4 g made up to 323.9 g with the solvent), is injected continuously into the reaction mixture in accordance with the following program: % 53.9 g/h of isocyanate solution for 360 minutes.

(65) In parallel the temperature is maintained at 81 C. during injection and then is raised to 110 C. over 60 minutes and held at 110 C. for a further 3 hours after the end of introduction of the isocyanate.

(66) The polymerization is at an end and the reactor is almost clean. After cooling to 80 C., decanting, and drying, the particle size is between 2 and 30 m, with an average particle diameter of 9.2 m. DSC analysis shows Tf=142.4 C. and Tc=108.7 C.

Comparative Example 12

PA6/12 Seeded with PA6

(67) The reactor, maintained under nitrogen, is charged with 2800 ml of solvent and then, in succession, with 323 g of caprolactam, 575 g of lactam12, 30.9 g of EBS, and 54 g of ORGASOL 1002D NAT. After the stirring has been commenced at 300 rpm, heating is carried out gradually to 110 C., and then 290 ml of solvent are distilled off under vacuum in order, azeotropically, to entrain any trace of water that might be present.

(68) Following a return to atmospheric pressure, the anionic catalyst and 9 g of sodium hydride at 60% purity in oil are introduced rapidly under nitrogen, and the stirring is increased to 550 rpm, under nitrogen at 110 C. for 30 minutes.

(69) Subsequently the temperature is taken to 81 C. and this temperature is maintained for 30 minutes. Using a small metering pump, the selected activator, namely stearyl isocyanate (32.4 g made up to 323.9 g with the solvent) is injected continuously into the reaction mixture in accordance with the following program: % 53.9 g/h of isocyanate solution for 360 minutes.

(70) In parallel the temperature is maintained at 81 C. during injection and then is raised to 110 C. over 60 minutes and held at 110 C. for a further 3 hours after the end of introduction of the isocyanate.

(71) The polymerization is at an end and the reactor is almost clean. After cooling to 80 C., decanting, and drying, the particle size is between 5 and 80 m, with an average particle diameter of 31 m. DSC analysis shows Tf=141.8 C., Tf=210.7 C. and Tc=92.9 C.

(72) TABLE-US-00001 TABLE 1 Comp. Inv. Comp. Inv. Inv. Inv. Comp. Example 1 2 3 4 5 6 7 Lactam6 (g) 108 108 108 108 899 899 899 Lactam12 (g) 791 679 791 791 / EBS (g) 14.4 14.4 12.6 12.6 7.2 7.2 7.2 Inorganic filler (g) 12.6 16.2 5.75 Organic 112 18.7 54 54 filler (g) (PA12) (PA12) (PA12) (PA6) Stearyl 32.9 32.9 32.9 16.54 .sup.37.3 37.3 37.3 isocyanate (g) NaH (g) 7.2 .sup.7.2 7.2 5.4 5.8 5.8 5.8 Average diameter (m) 9.9 11.8 23.8 18.8 31 45.8 23.0 Melting 163 161.5* 162 166.9* 216* 214 216 temperature ( C.) 173** 171** Crystallization .sup.118.8 121.1 109.2* 176* 172 179 temperature ( C.) 144** |Tf Tc| .sup.43.3* 40.9 57.6 40* 42 37 27** *in the shell of the PA particle **in the core of the PA particle

(73) TABLE-US-00002 TABLE 2 Comp. Inv. Inv. Comp. Inv. Example 8 9 10 11 12 Lactam6 (g) / / / 323 323 Lactam12 (g) 899 899 899 575 575 EBS (g) 7.2 7.2 7.2 30.9 30.9 Inorganic 7.5 / / 10.8 / filler (g) Organic filler / 11.3 1. 65 / 54 (g) (PA12) (PA12) (PA6) Stearyl 19.2 19.2 19.2 32.4 32.4 isocyanate (g) NaH (g) 2.7 2.7 2.7 9 9 Average 36 50 46 9.2 31 diameter (m) Melting 183 183.8 183 142.4 141.8* temperature 210.7** Tf1 ( C.) Crystallization 138.2 134.7 135.7 108.7 92.9* temperature ( C.) |Tf Tc| 44.8 49.1 47.2 33.7 48.9 Solution viscosity, 0.72 0.79 0.72 organic filler Solution viscosity, 1.35 1.32 1.33 0.65 0.64 eventual powder *in the shell of the PA particle **in the core of the PA particle