Pretreated material for laser sintering

Abstract

Disclosed is a composition, in particular to a building material for an additive manufacturing process, wherein the composition is treated by heat. Further, the present invention is directed to a process for the manufacturing of the inventive composition and to a device comprising the inventive composition and the use of the inventive composition.

Claims

1. A composition comprising: at least one polymer in the form of a dry powder, wherein the at least one polymer comprises at least one thermoplastic polymer selected from the group consisting of a polyetherimide, a polycarbonate, a polysulfone, a polyphenylene sulfone, a polyphenylene oxide, a polyether sulfone, an acrylnitrile-butadiene-styrol-copolymer (ABS), an acrylnitrile-styrol-acrylate-copolymer (ASA), a polyvinyl chloride, a polyacrylate, a polyester, a polyamide, a polypropylene, a polyethylene, a polyarylether ketone, a polyether, a polyurethane, a polyimide, polyamide imide, a polyolefine, a polyarylene sulfide and copolymers thereof; wherein the at least one polymer is treated by heat at a temperature of at least about 0.1? C. below a melting point of the at least one polymer and not more than about 2? C. below the melting point; wherein the heat treatment is carried out in a dry state of the powder for at least about 1 hour and/or not more than about 24 hours; and wherein the at least one polymer has polymer particles with a particle size distribution as follows: d10=at least 30 ?m and/or not more than 50 ?m; d50=at least 70 ?m and/or not more than 90 ?m; and d90=at least 90 ?m and/or not more than 120 ?m.

2. A composition according to claim 1, wherein the at least one polymer comprises at least one semicrystalline polymer and/or at least one amorphous polymer.

3. A composition according to claim 1, further comprising a polypropylene and/or a copolymer and/or a polymer blend thereof.

4. A composition according to claim 1, wherein the polypropylene has a melting temperature T.sub.m, of at least about 100? C., and/or wherein the polypropylene has a glass transition temperature T.sub.g of at least about ?25? C.

5. A composition according to claim 2, having a process window of at least about 10? C.

6. A composition according to claim 1, further comprising at least one flow agent.

7. A process for the manufacture of a composition according to claim 1, wherein the process comprises the following steps: providing the at least one thermoplastic polymer selected from the group consisting of a polyetherimide, a polycarbonate, a polysulfone, a polyphenylene sulfone, a polyphenylene oxide, a polyether sulfone, an acrylnitrile-butadiene-styrol-copolymer (ABS), an acrylnitrile-styrol-acrylate-copolymer (ASA), a polyvinyl chloride, a polyacrylate, a polyester, a polyamide, a polypropylene, a polyethylene, a polyarylether ketone, a polyether, a polyurethane, a polyimide, polyamide imide, a polyolefine, a polyarylene sulfide and copolymers thereof; and treating the at least one polymer by heat in a dry state of the powder at a temperature of at least about 0.1? C. below the melting point and not more than about 2? C. below the melting point for at least about 1 hour and/or not more than about 24 hours.

8. A process for the manufacture of a composition according to claim 7, wherein the process comprises the following steps: treating the at least one thermoplastic polymer by heat to increase a difference between a melting temperature and/or an onset melting temperature and a recrystallisation temperature and/or onset recrystallisation temperature; and/or treating the least one thermoplastic polymer by heat to increase a temperature at which onset of melting occurs.

9. A composition comprising: at least one polymer in the form of a dry powder, wherein the at least one polymer comprises at least one thermoplastic polymer selected from the group consisting of a polyetherimide, a polycarbonate, a polysulfone, a polyphenylene sulfone, a polyphenylene oxide, a polyether sulfone, an acrylnitrile-butadiene-styrol-copolymer (ABS), an acrylnitrile-styrol-acrylate-copolymer (ASA), a polyvinyl chloride, a polyacrylate, a polyester, a polyamide, a polypropylene, a polyethylene, a polyarylether ketone, a polyether, a polyurethane, a polyimide, polyamide imide, a polyolefine, a polyarylene sulfide and copolymers thereof; wherein the at least one polymer is treated by heat at a temperature of at least about 0.1? C. below a melting point of the at least one polymer and not more than about 2? C. below the melting point; wherein the heat treatment is carried out in a dry state of the powder for at least about 1 hour and/or not more than about 24 hours; and wherein the composition has a particle distribution width (d90?d10)/d50 of at least 0.50.

10. A composition comprising: at least one polymer in the form of a dry powder, wherein the at least one polymer comprises at least one thermoplastic polymer selected from the group consisting of a polyetherimide, a polycarbonate, a polysulfone, a polyphenylene sulfone, a polyphenylene oxide, a polyether sulfone, an acrylnitrile-butadiene-styrol-copolymer (ABS), an acrylnitrile-styrol-acrylate-copolymer (ASA), a polyvinyl chloride, a polyacrylate, a polyester, a polyamide, a polypropylene, a polyethylene, a polyarylether ketone, a polyether, a polyurethane, a polyimide, polyamide imide, a polyolefine, a polyarylene sulfide and copolymers thereof; wherein the at least one polymer is treated by heat at a temperature of at least about 0.1? C. below a melting point of the at least one polymer and not more than about 2? C. below the melting point; wherein the heat treatment is carried out in a dry state of the powder for at least about 1 hour and/or not more than about 24 hours; and wherein the at least one polymer has polymer particles with a sphericity of at least about 0.8.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further characteristics of the present invention are derived from the examples in combination with the claims and the figures. Single features may be, in a particular embodiment, realised in combination with other features and do not limit the scope of protection of the present invention. The following description of the examples according to the invention may relate to the figures, whereby

(2) FIG. 1 shows the DSC curves for the untreated and treated Polymer 05 pellets (heat treatment 142? C. for 6 hrs). There is a clear increase in both the Tmo and Tm of the material as well as a reduction in the difference between the Tmo and Tm.

(3) FIG. 2 shows the DSC curves for the untreated and treated Polymer 09 pellets (heat treatment 147? C. for 8 hrs). Increases to the Tmo and Tm as well as a reduction in the difference between the Tmo and Tm are displayed.

(4) FIG. 3 shows the DSC curves for the untreated and treated Polymer 18 pellets (heat treatment 147? C. for 8 hrs). Increases to the Tmo and Tm as well as a reduction in the difference between the Tmo and Tm are displayed.

DETAILED DESCRIPTION OF THE EMBODIMENTS

EXAMPLES

(5) Materials:

(6) a) Polymer 05 (Braskem, Polypropylene pellets) b) Polymer 09 (Braskem, Polypropylene pellets) c) Polymer 18 (Braskem, Polypropylene pellets)
Heat Treatment:

(7) The polymer samples listed above were heated in a heating device (Grieve, Truck Oven TCH-550). The optimal heating parameters for each polymer sample were as follows: (1) Polymer 05 was heated to a temperature of 142? C. for 6 hours, (2) Polymer 09 was heated to a temperature of 147? C. for 8 hours, and (3) Polymer 18 was heated to a temperature of 147? C. for 8 hours.
Temperature Measurements by DSC:

(8) The temperature measurements for all samples listed above were produced according to ASTM D3418-03 (Standard Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallisation of Polymers by Differential Scanning calorimetry) with a TA Instruments TA Q20 DSC tool.

(9) For the evaluation of the Tm, the Trc and the onset points Tmo and Tro, standard aluminum pans were used and the heating and cooling was performed for all samples as follows: (1) equilibrating at 40? C., (2) ramping at 10? C./min to 175? C., (3) holding isothermal for 1 minute, (4) ramping at ?10? C./min to 40? C., (5) holding isothermal for 1 minute. The melting point of polypropylene in general can range between 120?170? C.

(10) TABLE-US-00001 TABLE 1 Melt and recrystallisation data for various heat treated Polymer 05 samples. Melting Melting Recrys- Recrys- Peak Onset tallisation tallisation Sample (Tm) (Tmo) Peak (Trc) Onset (Tro) Polymer 05 143.86? C. 124.12? C. 106.08? C. 109.86? C. Control Sample, Untreated Polymer 05, 149.87? C. 141.72? C. 106.06? C. 109.83? C. heat treated 6 hours at 142? C. Polymer 05, 143.44? C. 130.33? C. 107.22? C. 111.33? C. heat treated 16 hours at 128? C. Polymer 05, 144.83? C. 132.01? C. 107.30? C. 111.53? C. heat treated 16 hours at 131? C. Polymer 05, 145.23? C. 136.35? C. 107.57? C. 111.54? C. heat treated 14 hours at 135? C.

(11) TABLE-US-00002 TABLE 2 Melt and recrystallisation data for various heat treated Polymer 09 samples. Melting Melting Recrys- Recrys- Peak Onset tallisation tallisation Sample (Tm) (Tmo) Peak (Trc) Onset (Tro) Polymer 09 147.67? C. 134.00? C. 104.89? C. 108.18? C. Control Sample, Untreated Polymer 09, 154.29? C. 146.97? C. 103.32? C. 107.35? C. heat treated 8 hours at 147? C.

(12) TABLE-US-00003 TABLE 3 Melt and recrystallisation data for various heat treated Polymer 18 samples. Melting Melting Recrys- Recrys- Peak Onset tallisation tallisation Sample (Tm) (Tmo) Peak (Trc) Onset (Tro) Polymer 18 147.94? C. 135.45? C. 119.07? C. 122.64? C. Control Sample, Untreated Polymer 18, 153.49? C. 146.77? C. 118.57? C. 122.23? C. heat treated 8 hours at 147? C.
Grinding

(13) The polymer samples are then optionally ground to a powder with particle size d50 of 80 ?m in a cryogenic grinding process (Vortec, Impact Mill M-1).

(14) Laser Sintering

(15) Now that the polymer samples are in powder form they can be used in the SLS machines (Integra, Sinterstation 2500 Plus) and (EOS, P396).

(16) The invention illustratively described herein suitably may be practised in the absence of any element or elements, limitation or limitations which is/are not specifically disclosed herein. Thus, for example, in each instance herein any of the terms comprising, consisting essentially of and consisting of may be replaced with either of the other two terms. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.

(17) All references cited in this specification are herewith incorporated by reference with respect to their entire disclosure content and the disclosure content specifically mentioned in this specification.