权利要求：
1. An additive manufacturing method for making a three-dimensional (3D) object, comprising:
a) providing a powdered polymer material (M) comprising:
from 55 to 95 wt. % of at least one poly(ether ether ketone) (PEEK) polymer,
wherein the PEEK polymer comprises at least 50 mol. % of recurring units (RPEEK) of formula (J-A), based on the total number of moles in the polymer:
where R′, at each location, is independently selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium;
where j′, for each R′, is independently zero or an integer ranging from 1 to 4; and
from 5 to 45 wt. % of at least one poly(aryl ether sulfone) (PAES) polymer, based on the total weight of the powdered polymer material (M), wherein the PAES polymer comprising at least 50 mol. % of recurring units (RpAEs) of formula (K), based on the total number of moles in the polymer:
where R, at each location, is independently selected from the group consisting of a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium;
where h, for each R, is independently zero or an integer ranging from 1 to 4; and
where T is selected from the group consisting of a bond and a group—C(Rj)(Rk)—, where Rj and Rk, equal to or different from each other, are selected from the group consisting of a hydrogen, a halogen, an alkyl, an alkenyl, an alkynyl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium;
b) depositing successive layers of the powdered polymer material (M); and
c) selectively sintering each layer prior to deposition of the subsequent layer, wherein the powdered polymer material (M) is heated before step c) to a temperature Tp (° C.):
Tp<Tg+40
wherein Tg (° C.) is the glass transition temperature of the PAES polymer, as measured by differential scanning calorimetry (DSC) according to ASTM D3418.
2. The method of claim 1, wherein the powdered polymer material (M) has a dos-value ranging between 25 and 90 μm, as measured by laser scattering in isopropanol.
3. The method of claim 1 wherein the PAES polymer is a poly(biphenyl ether sulfone) (PPSU) polymer,
wherein PPSU denotes a polymer comprising at least 50 mol. % of recurring units (Rppsu) of formula (L), based on the total number of moles in the PPSU polymer:
where R, at each location, is independently selected from a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium; and
where h, for each R, is independently zero or an integer ranging from 1 to 4″.
4. The method of claim 1, wherein the powdered polymer material (M) is heated before step c) to a temperature Tp (° C.):
Tp<Tg+30
wherein Tg (° C.) is the glass transition temperature of the PAES polymer, as measured by differential scanning calorimetry (DSC) according to ASTM D3418.
5. The method of claim 1, wherein the powdered polymer material (M) comprises:
from 56 to 80 wt. % of at least one poly(ether ether ketone) (PEEK) polymer, and
from 20 to 44 wt. % of at least one poly(aryl ether sulfone) (PAES) polymer, based on the total weight of the powdered polymer material (M).
6. The method of claim 1, wherein the powdered polymer material (M) further comprises 0.01 to 10 wt. % of a flow agent.
7. The method of claim 1, wherein the PAES has a Tg ranging from 160 and 250° C., as measured by differential scanning calorimetry (DSC) according to ASTM D3418.
8. The method of claim 1, wherein the powdered polymer material (M) is obtained by grinding a blend of at least the PEEK polymer and the PAES polymer, the blend being optionally cooled down to a temperature below 25° C. before and/or during grinding.
9. The method of claim 1, wherein step c) comprises selective sintering by means of an electromagnetic radiation of the powder.
10. A method for manufacturing a three-dimensional (3D) object comprising using selective laser sintering (SLS) with a powdered polymer material (M) having a d0.5 value ranging from 25 to 90 μm and comprising:
from 55 to 95 wt. % of at least one poly(ether ether ketone) (PEEK) polymer, wherein the PEEK polymer denotes a polymer comprising at least 50 mol. % of the recurring units of formula (J″-A):
the mol. % being based on the total number of moles in the polymer
from 5 to 45 wt. % of at least one poly(aryl ether sulfone) (PAES) polymer, based on the total weight of the powdered polymer material (M), wherein the PAES polymer denotes a polymer comprising at least 50 mol. % of recurring units of formula (K′), based on the total number of moles in the polymer:
and
a flow agent selected from the group consisting of silicas, aluminas and titanium oxide.
11. The method of claim 1, wherein the PAES polymer is a polysulfone (PSU) polymer, wherein PSU denotes a polymer comprising at least 50 mol. % recurring units (RPSU) of formula (N), the mol. % being based on the total number of moles in the polymer:
where R, at each location, is independently selected from a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium; and
where h, for each R, is independently zero or an integer ranging from 1 to 4″.
12. The method of claim 1, wherein the PEEK has at least 50 mol. % of recurring units of formula (J″-A):
the mol. % being based on the total number of moles in the polymer.
13. The method of claim 1, wherein the PEEK has at least 80 mol. % of recurring units of formula (J″-A):
the mol. % being based on the total number of moles in the polymer.
14. The method of claim 1, wherein the PEEK has at least 90 mol. % of recurring units of formula (J″-A):
the mol. % being based on the total number of moles in the polymer.
15. The method of claim 1, wherein the PEEK has at least 95 mol. % of recurring units of formula (J″-A):
the mol. % being based on the total number of moles in the polymer.
16. The method of claim 1, wherein the PEEK is a copolymer that has at least 50 mol. % of recurring units of formula (J″-A):
the mol. % being based on the total number of moles in the polymer, and
wherein the PEEK has less than 50 mol. % of recurring units of formula (J″-D):
the mol. % being based on the total number of moles in the polymer.
17. The method of claim 1, wherein the PAES polymer is a PPSU comprising at least 50 mol. % of recurring units of formula (L″):
the mol. % being based on the total number of moles in the polymer.
18. The method of claim 1, wherein the PAES polymer is a PPSU comprising at least 80 mol. % of recurring units of formula (L″):
the mol. % being based on the total number of moles in the polymer.
19. The method of claim 1, wherein the PAES polymer is a PPSU comprising at least 90 mol. % of recurring units of formula (L″):
the mol. % being based on the total number of moles in the polymer.
20. The method of claim 1, wherein the PAES polymer is a PPSU comprising at least 95 mol. % of recurring units of formula (L″):
the mol. % being based on the total number of moles in the polymer.
21. The method of claim 1, wherein the PAES polymer is a PSU comprising at least 50 mol. % of recurring units of formula (N″):
the mol. % being based on the total number of moles in the polymer.
22. The method of claim 1, wherein the PAES polymer is a PSU comprising at least 80 mol. % of recurring units of formula (N″):
the mol. % being based on the total number of moles in the polymer.
23. The method of claim 1, wherein the PAES polymer is a PSU comprising at least 90 mol. % of recurring units of formula (N″):
the mol. % being based on the total number of moles in the polymer.
24. The method of claim 1, wherein the PAES polymer is a PSU comprising at least 95 mol. % of recurring units of formula (N″):
the mol. % being based on the total number of moles in the polymer.
具体实施方式：
[0019]The present invention relates to an additive manufacturing method for making a three-dimensional (3D) object. The method comprises a first step of providing a powdered polymer material (M) comprising from 55 to 95 wt. % of at least one poly(ether ether ketone) (PEEK) polymer, and from 5 to 45 wt. % of at least one poly(aryl ether sulfone) (PAES) polymer, based on the total weight of the powdered polymer material (M). The method of the invention also comprises a step of depositing successive layers of the powdered polymer material and a step of selectively sintering each layer prior to deposition of the subsequent layer.
[0020]According to the present invention, the powdered polymer material (M) is heated before the sintering step to a temperature Tp (° C.):
Tp<Tg+40
[0021]wherein Tg (° C.) is the glass transition temperature of the PAES polymer, as measured by differential scanning calorimetry (DSC) according to ASTM D3418.
[0022]The method of the present invention employs a powdered polymer material (M) comprising a PEEK polymer as the main element of the polymer material, as well as a PAES polymer. The powdered polymer material (M) can have a regular shape such as a spherical shape, or a complex shape obtained by grinding/milling of pellets or coarse powder.
[0023]In the process of the present invention, the powdered polymer material (M) is heated, for example in the powder bed of a SLS printer, prior to the sintering of a selected area of the powder layer (for example, by means of an electromagnetic radiation of the powder), at a processing temperature (Tp) which is Tp<Tg+40, where Tg is the glass transition temperature of the PAES amorphous polymer. The combination of the material and the choice of a specific processing temperature (Tp), based on the material composition, makes possible the recycling of the unsintered material and its reuse in the manufacture of a new 3D object. The powdered polymer material (M) is not significantly affected by the long-term exposure to the processing temperature and presents a set of characteristics (namely powder aspect and color, disaggregation and coalescence abilities) which is comparable to a new, unprocessed polymer material. This makes the used powder completely suitable for reuse in a laser sintering 3D printing process, without impacting the appearance and mechanical performances of the resulting printed article (notably the expected performance of the polymer materials, e.g. the toughness of the PEEK).
Powdered Polymer Material (M)
[0024]The powdered polymer material (M) employed in the method of the present invention comprises:[0025]from 55 to 95 wt. % of at least one poly(ether ether ketone) (PEEK) polymer, and[0026]from 5 to 45 wt. % of at least one poly(aryl ether sulfone) (PAES) polymer, based on the total weight of the powdered polymer material (M).
[0027]The powdered polymer material (M) of the invention may include other components. For example, the material (M) may comprise at least one additive, notably at least one additive selected from the group consisting of flow agents, fillers, colorants, lubricants, plasticizers, stabilizers, flame retardants, nucleating agents and combinations thereof. Fillers in this context can be reinforcing or non-reinforcing in nature.
[0028]In embodiments that include flow agents, the amount of flow agents in the material (M) ranges from 0.01 to 10 wt. %, with respect to the total weight of the part material.
[0029]In embodiments that include fillers, the amount of fillers in the material (M) ranges from 0.5 wt. % to 30 wt. %, with respect to the total weight of the material (M). Suitable fillers include calcium carbonate, magnesium carbonate, glass fibers, graphite, carbon black, carbon fibers, carbon nanofibers, graphene, graphene oxide, fullerenes, talc, wollastonite, mica, alumina, silica, titanium dioxide, kaolin, silicon carbide, zirconium tungstate, boron nitride and combinations thereof.
[0030]According to one embodiment, the material (M) of the present invention comprises:[0031]from 56 to 95 wt. %, from 57 to 90 wt. %, from 58 to 85 wt. % or from 59 to 80 wt. % of at least one poly(ether ether ketone) (PEEK) polymer,[0032]from 5 to 44 wt. %, from 10 to 43 wt. %, from 15 to 42 wt. % or from 20 to 41 wt. % of at least one poly(aryl ether sulfone) (PAES) polymer,[0033]from 0 to 30 wt. % of at least one additive, for example selected from the group consisting of flow agents, fillers, colorants, dyes, pigments, lubricants, plasticizers, flame retardants (such as halogen and halogen free flame retardants), nucleating agents, heat stabilizer, light stabilizer, antioxidants, processing aids, nanofillers and electromagnetic absorbers, based on the total weight of the powdered polymer material (M).
[0034]According to one embodiment, the material (M) of the present invention comprises:[0035]from 56 to 95 wt. %, from 57 to 90 wt. %, from 58 to 85 wt. % or from 59 to 80 wt. % of at least one poly(ether ether ketone) (PEEK) polymer,[0036]from 5 to 44 wt. %, from 10 to 43 wt. %, from 15 to 42 wt. % or from 20 to 41 wt. % of at least one poly(biphenyl ether sulfone) polymer (PPSU) polymer and/or one polysulfone (PSU) polymer,[0037]from 0 to 30 wt. % of at least one additive, or from 0.1 to 28 wt. % or from 0.5 to 25 wt. % of at least one additive, for example selected from the group consisting of flow agents, fillers, colorants, dyes, pigments, lubricants, plasticizers, flame retardants (such as halogen and halogen free flame retardants), nucleating agents, heat stabilizer, light stabilizer, antioxidants, processing aids, nanofillers and electromagnetic absorbers, based on the total weight of the powdered polymer material (M).
Poly(Ether Ether Ketone) (PEEK)
[0038]As used herein, a poly(ether ether ketone) (PEEK) denotes any polymer comprising at least 50 mol. % of recurring units (RPEEK) of formula (J-A), based on the total number of moles in the polymer:
[0039]
[0040]where[0041]R′, at each location, is independently selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium; and[0042]j′, for each R′, is independently zero or an integer ranging from 1 to 4 (for example 1, 2, 3 or 4).
[0043]Each phenylene moiety of the recurring unit (RPEEK) may, independently from one another, have a 1,2-, a 1,3- or a 1,4-linkage to the other phenylene moieties. According to an embodiment, each phenylene moiety of the recurring unit (RPEEK), independently from one another, has a 1,3- or a 1,4-linkage to the other phenylene moieties. According to another embodiment yet, each phenylene moiety of the recurring unit (RPEEK) has a 1,4-linkage to the other phenylene moieties.
[0044]According to an embodiment, R′ is, at each location in formula (J-A) above, independently selected from the group consisting of a C1-C12 moiety optionally comprising one or more than one heteroatoms; sulfonic acid and sulfonate groups; phosphonic acid and phosphonate groups; amine and quaternary ammonium groups.
[0045]According to another embodiment, j′ is zero for each R′. In other words, according to this embodiment, the recurring units (RPEEK) are according to formula (J′-A):
[0046]
[0047]According to an embodiment of the present disclosure, at least 50 mol. %, at least 60 mol. %, at least 70 mol. %, at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, at least 99 mol. % or all of the recurring units in the PEEK are recurring units (RPEEK) of formulae (J-A) and/or (J′-A).
[0048]According to another embodiment of the present disclosure, a poly(ether ether ketone) (PEEK) denotes any polymer comprising at least 50 mol. % of the recurring units are recurring units (RPEEK) of formula (J-A″):
[0049]
[0050]the mol. % being based on the total number of moles in the polymer.
[0051]According to an embodiment of the present disclosure, at least 50 mol. %, at least 60 mol. %, at least 70 mol. %, at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, at least 99 mol. % or all of the recurring units in the PEEK are recurring units (RPEEK) of formula (J″-A).
[0052]The PEEK polymer of the present disclosure can therefore be a homopolymer or a copolymer. If it is a copolymer, it can be a random, alternate or block copolymer.
[0053]When the poly(ether ether ketone) (PEEK) is a copolymer, it can be made of recurring units (R*PEEK), different from recurring units (RPEEK), such as recurring units of formula (J-D):
[0054]
[0055]where[0056]R′, at each location, is independently selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium; and[0057]j′, for each R′, is independently zero or an integer ranging from 1 to 4.
[0058]According to an embodiment, R′ is, at each location in formula (J-D) above, independently selected from the group consisting of a C1-C12 moiety optionally comprising one or more than one heteroatoms; sulfonic acid and sulfonate groups; phosphonic acid and phosphonate groups; amine and quaternary ammonium groups.
[0059]According to an embodiment, j′ is zero for each R′. In other words, according to this embodiment, the recurring units (R*PEEK) are according to formula (J′-D):
[0060]
[0061]According to another embodiment of the present disclosure, the recurring units (R*PEEK) are according to formula (J-D″):
[0062]
[0063]According to an embodiment of the present disclosure, less than 50 mol. %, less than 40 mol. %, less than 30 mol. %, less than 20 mol. %, less than 10 mol. %, less than 5 mol. %, less than 1 mol. % or all of the recurring units in the PEEK are recurring units (R*PEEK) of formulas (J-D), (J′-D), and/or (J″-D).
[0064]According to an embodiment, the PEEK polymer is a PEEK-PEDEK copolymer. As used herein, a PEEK-PEDEK copolymer denotes a polymer comprising recurring units (RPEEK) of formula (J-A), (J′-A) and/or (J″-A) and recurring units (R*PEEK) of formulas (J-D), (J′D) or (J″-D) (also called hereby recurring units (RPEDEK)). The PEEK-PEDEK copolymer may include relative molar proportions of recurring units (RPEEK/RPEDEK) ranging from 95/5 to 51/49, from 90/10 to 55/45, or from 85/15 to 56/44. The sum of recurring units (RPEEK) and (RPEDEK) can for example represent at least 60 mol. %, 70 mol. %, 80 mol. %, 90 mol. %, 95 mol. %, 99 mol. %, of recurring units in the PEEK copolymer. The sum of recurring units (RPEEK) and (RPEDEK) can also represent 100 mol. %, of recurring units in the PEEK copolymer.
[0065]Defects, end groups and monomers' impurities may be incorporated in very minor amounts in the polymer (PEEK) of the present disclosure, so as to advantageously not affecting negatively the performances of the same.
[0066]PEEK is commercially available as KetaSpire® PEEK from Solvay Specialty Polymers USA, LLC.
[0067]PEEK can be prepared by any method known in the art. It can for example result from the condensation of 4,4′-difluorobenzophenone and hydroquinone in presence of a base. The reactor of monomer units takes place through a nucleophilic aromatic substitution. The molecular weight (for example the weight average molecular weight Mw) can be adjusted by adjusting the monomers molar ratio and measuring the yield of polymerisation (e.g. measure of the torque of the impeller that stirs the reaction mixture).
[0068]According to one embodiment of the present disclosure, the powdered polymer material (M) comprises at least one PEEK polymer having a weight average molecular weight (Mw) ranging from 50,000 to 150,000 g/mol, for example from 55,000 to 130,000 g/mol, from 60,000 to 120,000 g/mol, from 65,000 to 110,000 g/mol, or from 70,000 to 100,000 g/mol (as determined by gel permeation chromatography (GPC) using phenol and trichlorobenzene (1:1) at 160° C., with polystyrene standards).
[0069]According to another embodiment, the powdered polymer material (M) comprises at least two PEEK polymers of different Mw. In this case, the blend may for example comprise:[0070]a PEEK polymer having a Mw ranging from 50,000 to 85,000 g/mol, for example from 52,000 to 83,000 g/mol or from 54,000 to 81,000 g/mol, and[0071]a PEEK polymer having a Mw ranging from 85,000 to 120,000 g/mol, from 87,000 to 118,000 g/mol or from 89,000 to 116,000 g/mol, as determined by gel permeation chromatography (GPC) using phenol and trichlorobenzene (1:1) at 160° C., with polystyrene standards.
[0072]The weight average molecular weight (Mw) of PEEK, can be determined by gel permeation chromatography (GPC) using phenol and trichlorobenzene (1:1) at 160° C. (2× PL Gel mixed B, 10 m, 300×7.5 mm using a Polymer Laboratories PL-220 unit; flow rate: 1.0 mL/min; injection volume: 200 μL of a 0.2w/v % sample solution), with polystyrene standards.
[0073]More precisely, the weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC) as described in the experimental section. According to a detailed method, samples are dissolved in a 1:1 mixture of phenol and 1,2,4-trichlorobenzene at 190° C. temperature. Samples are then passed through 2× PL Gel mixed B, 10 m, 300×7.5 mm using a Polymer Laboratories PL-220 unit maintained at 160° C. equipped with a differential refractive index detector and calibrated with 12 narrow molecular weight polystyrene standards (Peak molecular weight range: 1,000-1,000,000). A flow rate of 1.0 mL/min and injection volume of 200 μL of a 0.2w/v % sample solution are selected.
[0074]The polymers can be characterized by their weight average molecular weight (Mw), and they can also be characterized by their polydispersity index (“PDI” or “PDI index” herewith), also called sometimes polymolecularity index. The PDI index corresponds to the molar weight distribution of the various macromolecules within the polymer. The PDI index corresponds to the ratio Mw/Mn, Mn being the number average molecular weight and determined by GPC.
[0075]According to another embodiment of the present disclosure, the PDI index of the PEEK polymer or PEEK polymers blend is from 1.8 to 2.5, for example from 1.9 to 2.4 or 1.95 to 2.3.
[0076]According to the present invention, the melt flow rate or melt flow index (at 400° C. under a weight of 2.16 kg according to ASTM D1238) (MFR or MFI) of the PEEK may be from 1 to 60 g/10 min, for example from 2 to 50 g/10 min or from 2 to 40 g/10 min.
[0077]According to one embodiment, the melt flow rate (at 400° C. under a weight of 2.16 kg according to ASTM D1238) of the PEEK is from 1 to 10 g/10 min, for example from 1.5 to 8 g/10 min or from 2 to 5 g/10 min.
[0078]According to another embodiment, the melt flow rate (at 400° C. under a weight of 2.16 kg according to ASTM D1238) of the PEEK is from 20 to 60 g/10 min, for example from 25 to 55 g/10 min or from 27 to 50 g/10 min.
Poly(Aryl Ether Sulfone) (PAES)
[0079]For the purpose of the present invention, a “poly(aryl ether sulfone) (PAES)” denotes any polymer comprising at least 50 mol. % of recurring units (RPAES) of formula (K), based on the total number of moles in the polymer:
[0080]
[0081]where[0082]R, at each location, is independently selected from a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium;[0083]h, for each R, is independently zero or an integer ranging from 1 to 4; and[0084]T is selected from the group consisting of a bond and a group —C(Rj)(Rk)-, where Rj and Rk, equal to or different from each other, are selected from a hydrogen, a halogen, an alkyl, an alkenyl, an alkynyl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium.
[0085]According to an embodiment, Rj and Rk are methyl groups.
[0086]According to an embodiment, h is zero for each R. In other words, according to this embodiment, the recurring units (RPAES) are units of formula (K′):
[0087]
[0088]According to an embodiment of the present invention, at least 60 mol. %, at least 70 mol. %, at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, at least 99 mol. % or all of the recurring units in the PAES are recurring units (RPAES) of formula (K) or formula (K′).
[0089]According to an embodiment, the PAES has a Tg ranging from 160 and 250° C., preferably from 170 and 240° C., more preferably from 180 and 230° C., as measured by differential scanning calorimetry (DSC) according to ASTM D3418.
[0090]According to an embodiment, the poly(aryl ether sulfone) (PAES) is a poly(biphenyl ether sulfone) (PPSU).
[0091]A poly(biphenyl ether sulfone) polymer is a polyarylene ether sulfone which comprises a biphenyl moiety. Poly(biphenyl ether sulfone) is also known as polyphenyl sulfone (PPSU) and for example results from the condensation of 4,4′-dihydroxybiphenyl (biphenol) and 4,4′-dichlorodiphenyl sulfone.
[0092]For the purpose of the present invention, a poly(biphenyl ether sulfone) (PPSU) denotes any polymer comprising at least 50 mol. % of recurring units (RPPSU) of formula (L), based on the total number of moles in the PPSU polymer:
[0093]
[0094]where[0095]R, at each location, is independently selected from a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium;[0096]h, for each R, is independently zero or an integer ranging from 1 to 4.
[0097]According to an embodiment, R is, at each location in formula (L) above, independently selected from the group consisting of a C1-C12 moiety optionally comprising one or more than one heteroatoms; sulfonic acid and sulfonate groups; phosphonic acid and phosphonate groups; amine and quaternary ammonium groups.
[0098]According to an embodiment, h is zero for each R. In other words, according to this embodiment, the recurring units (RPPSU) are units of formula (L′):
[0099]
[0100]According to another embodiment, the recurring units (RPPSU) are units of formula (L″):
[0101]
[0102]The PPSU polymer of the present invention can therefore be a homopolymer or a copolymer. If it is a copolymer, it can be a random, alternate or block copolymer.
[0103]According to an embodiment of the present invention, at least 60 mol. %, at least 70 mol. %, at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, at least 99 mol. % or all of the recurring units in the PPSU are recurring units (RPPSU) of formula (L), (L′) and/or (L″).
[0104]When the poly(biphenyl ether sulfone) (PPSU) is a copolymer, it can be made of recurring units (R*PPSU), different from recurring units (RPPSU), such as recurring units of formula (M), (N″) and/or (O):
[0105]
[0106]The poly(biphenyl ether sulfone) (PPSU) can also be a blend of a PPSU homopolymer and at least one PPSU copolymer, as described above.
[0107]The poly(biphenyl ether sulfone) (PPSU) can be prepared by any method known in the art. It can for example result from the condensation of 4,4′-dihydroxybiphenyl (biphenol) and 4,4′-dichlorodiphenyl sulfone in presence of a base. The reaction of monomer units takes place through nucleophilic aromatic substitution with the elimination of one unit of hydrogen halide as leaving group. It is to be noted however that the structure of the resulting poly(biphenyl ether sulfone) does not depend on the nature of the leaving group.
[0108]PPSU is commercially available as Radel® PPSU from Solvay Specialty Polymers USA, L. L. C.
[0109]According to the present invention, the powdered polymer material (M) comprises from 5 to 45 wt. % of a poly(aryl ether sulfone) (PAES), for example from 5 to 45 wt. % of a poly(biphenyl ether sulfone) (PPSU).
[0110]According to one embodiment, the powdered polymer material (M) comprises from 15 to 43 wt. % or from 17 to 43 wt. %, of poly(biphenyl ether sulfone) (PPSU), based on the total weight of the powdered polymer material (M).
[0111]According to the present invention, the weight average molecular weight Mw of the PPSU may be from 30,000 to 80,000 g/mol, for example from 35,000 to 75,000 g/mol or from 40,000 to 70,000 g/mol.
[0112]According to the present invention, the melt flow rate or melt flow index (at 365° C. under a weight of 5 kg according to ASTM D1238) (MFR or MFI) of the PPSU may be from 1 to 60 g/10 min, for example from 5 to 50 g/10 min or from 10 to 40 g/10 min.
[0113]According to an embodiment, the poly(aryl ether sulfone) (PAES) in the powdered polymer material (M) is a polysulfone (PSU) polymer.
[0114]For the purpose of the present invention, a polysulfone (PSU) denotes any polymer comprising at least 50 mol. % recurring units (RPSU) of formula (N), the mol. % being based on the total number of moles in the polymer:
[0115]
[0116]where[0117]R, at each location, is independently selected from a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium;[0118]h, for each R, is independently zero or an integer ranging from 1 to 4.
[0119]According to an embodiment, R is, at each location in formula (N) above, independently selected from the group consisting of a C1-C12 moiety optionally comprising one or more than one heteroatoms; sulfonic acid and sulfonate groups; phosphonic acid and phosphonate groups; amine and quaternary ammonium groups.
[0120]According to an embodiment, h is zero for each R. In other words, according to this embodiment, the recurring units (RPSU) are units of formula (N′):
[0121]
[0122]According to an embodiment of the present invention, at least 60 mol. % (based on the total number of moles in the polymer), at least 70 mol. %, at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, at least 99 mol. % or all of the recurring units in the PSU are recurring units (RPSU) of formula (N) and/or (N′).
[0123]According to another embodiment, a polysulfone (PSU) denotes any polymer of which more at least 50 mol. % of the recurring units are recurring units (RPSU) of formula (N″):
[0124]
[0125]the mol. % being based on the total number of moles in the polymer.
[0126]According to an embodiment of the present invention, at least 60 mol. %, at least 70 mol. %, at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, at least 99 mol. % or all of the recurring units in the PSU are recurring units (RPSU) of formula (N″).
[0127]The PSU polymer of the present invention can therefore be a homopolymer or a copolymer. If it is a copolymer, it can be a random, alternate or block copolymer.
[0128]When the polysulfone (PSU) is a copolymer, it can be made of recurring units (R*PSU), different from recurring units (RPSU), such as recurring units of formula (L″), (M) and/or (O) above described.
[0129]The polysulfone (PSU) can also be a blend of a PSU homopolymer and at least one PSU copolymer, as described above.
[0130]PSU is available as Udel® PSU from Solvay Specialty Polymers USA, L. L. C.
[0131]According to the present invention, the powdered polymer material (M) comprises from 5 to 45 wt. % of a poly(aryl ether sulfone) (PAES), for example from 5 to 45 wt. % of a polysulfone (PSU).
[0132]According to one embodiment, the powdered polymer material (M) comprises from 15 to 43 wt. % or from 17 to 43 wt. %, of polysulfone (PSU), based on the total weight of the powdered polymer material (M).
[0133]According to the present invention, the weight average molecular weight Mw of the PSU may be from 30,000 to 85,000 g/mol, for example from 35,000 to 75,000 g/mol or from 40,000 to 70,000 g/mol.
[0134]According to the present invention, the melt flow rate or melt flow index (at 343° C. under a weight of 5 kg according to ASTM D1238) (MFR or MFI) of the PSU may be from 1 to 50 g/10 min, for example from 2 to 40 g/10 min or from 3 to 30 g/10 min.
[0135]The weight average molecular weight (Mw) of PAES, for example PPSU and PSU, can be determined by gel permeation chromatography (GPC) using methylene chloride as a mobile phase (2×5μ mixed D columns with guard column from Agilent Technologies; flow rate: 1.5 mL/min; injection volume: 20 μL of a 0.2 w/v % sample solution), with polystyrene standards.
[0136]More precisely, the weight average molecular weight (Mw) of the PAES polymer can be measured by gel permeation chromatography (GPC), using methylene chloride as the mobile phase. The following detailed method can for example be used: two 5μ mixed D columns with guard column from Agilent Technologies are used for separation. An ultraviolet detector of 254 nm is used to obtain the chromatogram. A flow rate of 1.5 ml/min and injection volume of 20 μL of a 0.2 w/v % solution in mobile phase are selected. Calibration is performed with 12 narrow molecular weight polystyrene standards (Peak molecular weight range: 371,000 to 580 g/mol).
Optional Components
[0137]The powdered polymer material (M) of the present invention may further comprise a flow agent, also called sometimes flow aid. This flow agent may for example be hydrophilic. Examples of hydrophilic flow aids are inorganic pigments notably selected from the group consisting of silicas, aluminas and titanium oxide. Mention can be made of fumed silica.
[0138]Fumed silicas are commercially available under the trade name Aerosil® (Evonik) and Cab-O-Sil® (Cabot).
[0139]According to an embodiment of the present invention, the powdered polymer material (M) comprises from 0.01 to 10 wt. %, preferably from 0.05 to 5 wt. %, more preferably from 0.25 to 1 wt. % of a flow agent, for example of fumed silica.
[0140]These silicas are composed of nanometric primary particles (typically between 5 and 50 nm for fumed silicas). These primary particles are combined to form aggregates. In use as flow agent, silicas are found in various forms (elementary particles and aggregates).
[0141]The powdered polymer material (M) of the present invention may further comprise one or several additives, such as lubricants, heat stabilizers, light stabilizers, antioxidants, pigments, processing aids, dyes, fillers, nanofillers or electromagnetic absorbers. Examples of these optional additives are titanium dioxide, zinc oxide, cerium oxide, silica or zinc sulphide, glass fibers, carbon fibers.
[0142]The powdered polymer material (M) of the present invention may further comprise flame retardants such as halogen and halogen free flame retardants.
Method for Making a Three-Dimensional (3D) Object
[0143]The additive manufacturing method for making a three-dimensional (3D) object of the present invention comprises:
[0144]a) the provision of a powdered polymer material (M) comprising:[0145]from 55 to 95 wt. % of at least one PEEK polymer, and[0146]from 5 to 45 wt. % of at least one PAES polymer, for example a PPSU and/or a PSU, based on the total weight of the powdered polymer material (M);
[0147]b) the deposition of successive layers of the powdered polymer material (M); and
[0148]c) the selective sintering of each layer prior to deposition of the subsequent layer,
[0149]wherein the powdered polymer material (M) is heated before step c) to a temperature Tp (° C.):
Tp<Tg+40
for example Tp≤Tg+30, or Tp≤Tg+20, or Tp≤Tg+10,[0150]wherein Tg (° C.) is the glass transition temperature of the PAES polymer, as measured by differential scanning calorimetry (DSC) according to ASTM D3418.
[0151]The method of the present invention is conducted at a temperature where the thermal aging of the powdered polymer material, which can be assessed by the polymer aspect (for example color), the coalescence ability and the disaggregation ability, is significantly reduced. In other words, the powdered material shows no significant signs of thermal aging, can be recycled and use to prepare a new article by laser sintering 3D printing, as such or in combination with neat powdered polymer material.
[0152]According to an embodiment, the step of printing layers comprises selective sintering by means of a high power energy source, for example a high power laser source such as an electromagnetic beam source.
[0153]The 3D object/article/part may be built on substrate, for example an horizontal substrate and/or on a planar substrate. The substrate may be moveable in all directions, for example in the horizontal or vertical direction. During the 3D printing process, the substrate can, for example, be lowered, in order for the successive layer of unsintered polymeric material to be sintered on top of the former layer of sintered polymeric material.
[0154]According to an embodiment, the process further comprises a step consisting in producing a support structure. According to this embodiment, the 3D object/article/part is built upon the support structure and both the support structure and the 3D object/article/part are produced using the same AM method. The support structure may be useful in multiple situations. For example, the support structure may be useful in providing sufficient support to the printed or under-printing, 3D object/article/part, in order to avoid distortion of the shape 3D object/article/part, especially when this 3D object/article/part is not planar. This is particularly true when the temperature used to maintain the printed or under-printing, 3D object/article/part is below the re-solidification temperature of the powder.
[0155]The method of manufacture usually takes place using a printer. The printer may comprise a sintering chamber and a powder bed, both maintained at determined at specific temperatures.
[0156]The powder to be printed can be pre-heated to a processing temperature (Tp), above the glass transition (Tg) temperature of the powder. The preheating of the powder makes it easier for the laser to raise the temperature of the selected regions of layer of unfused powder to the melting point. The laser causes fusion of the powder only in locations specified by the input. Laser energy exposure is typically selected based on the polymer in use and to avoid polymer degradation.
[0157]According to the present invention, the powder is not significantly affected by the long-term exposure to the processing temperature and presents a set of characteristics (namely powder aspect and color, disaggregation and coalescence abilities) which is comparable to a new, unprocessed polymer material. This makes the used powder completely suitable for reuse in a laser sintering 3D printing process, without impacting the appearance and mechanical performances of the resulting printed article (notably the expected performance of the polymer materials).
Method for Producing the Powdered Polymer Material (M)
[0158]The present invention also relates to a method for the production of a powdered polymer material (M), comprising at least one PEEK polymer and at least one PAES polymer, said method comprising: a) a step of mixing the polymers together, for example blend compounding the polymers, and b) a step of grinding the resulting blended formulation, for example in the form of pellets, in order to obtain a powdered polymer material (M) having for example a d0.5-value ranging from 25 from 90 μm, for example from 35 to 88 μm, or from 45 to 85 μm, as measured by laser scattering in isopropanol. The d0.5, also called D50, is known as the median diameter or the medium value of the particle size distribution, it is the value of the particle diameter at 50% in the cumulative distribution. It means that 50% of the particles in the sample are larger than the d0.5-value, and 50% of the particles in the sample are smaller than the d0.5-value. D50 is usually used to represent the particle size of group of particles.
[0159]The pellets of blended formulations can for example be ground in a pinned disk mill, a jet mill/fluidized jet mil with classifier, an impact mill plus classif