具体实施方式：
[0020]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 polymer (P1), and from 5 to 45 wt. % of at least one polymer (P2), based on the total weight of the powdered polymer material (M). The polymer (P1) of the present invention has a melting temperature (Tm) greater than 270° C., as measured by differential scanning calorimetry (DSC) according to ASTM D3418, and the polymer (P2) of the present invention has a glass transition temperature (Tg) between 130° C. and 240° C., and no melting peak, as measured by differential scanning calorimetry (DSC) according to ASTM D3418.
[0021]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.
[0022]According to the present invention, the powdered polymer material (M) is heated before the sintering step to a temperature Tp (° C.):
Tp<Tg+25
[0023]wherein Tg (° C.) is the glass transition temperature of the P2 polymer, as measured by differential scanning calorimetry (DSC) according to ASTM D3418.
[0024]The method of the present invention employs a powdered polymer material (M) comprising a semi-crystalline polymer (P1) as the main element of the polymer material, as well as an amorphous polymer (P2). 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.
[0025]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+25, where Tg is the glass transition temperature of the amorphous polymer (P2). 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 PAEK).
[0026]Powdered Polymer Material (M)
[0027]The powdered polymer material (M) employed in the method of the present invention comprises:[0028]from 55 to 95 wt. % of at least one polymer (P1) having a melting temperature (Tm) greater than 270° C., as measured by differential scanning calorimetry (DSC) according to ASTM D3418, and[0029]from 5 to 45 wt. % of at least one polymer (P2) having a glass transition temperature (Tg) between 130° C. and 240° C., and no melting peak, as measured by differential scanning calorimetry (DSC) according to ASTM D3418,
[0030]based on the total weight of the powdered polymer material (M).
[0031]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.
[0032]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.
[0033]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.
[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 polymer (P1) having a melting temperature (Tm) greater than 270° C., as measured by differential scanning calorimetry (DSC) according to ASTM D3418, and[0036]from 5 to 44 wt. %, from 10 to 43 wt. %, from 15 to 42 wt. % or from 20 to 41 wt. % of of at least one polymer (P2) having a glass transition temperature (Tg) between 130° C. and 240° C., and no melting peak, as measured by differential scanning calorimetry (DSC) according to ASTM D3418,[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 electomagnetic absorbers, based on the total weight of the powdered polymer material (M).
[0038]Polymer (P1)
[0039]According to an embodiment, the polymer (P1) is selected from the group consisting of a poly(aryl ether ketone) (PAEK), a polyphenylene sulfide (PPS), a polyphtalamide (PPA), a semi-aromatic polyester and an aromatic polyesters (PE).
[0040]When P1 is a PAEK, it is preferably a poly(ether ether ketone) (PEEK), a poly(ether ketone ketone) (PEKK), a poly(ether ketone) (PEK) or a copolymer of PEEK and poly(diphenyl ether ketone) (PEEK-PEDEK copolymer).
[0041]When the polymer is a PAS, it is preferably a poly(para-phenylene sulfide).
[0042]When the polymer is a PE, it is preferably a polyethylene naphthalate (PEN), a poly(1,4 cyclohexylenedimethylene terephthalate) (PCT) or a Liquid Crystalline Polyester (LCP).
[0043]Poly(aryl ether ketone) (PAEK)
[0044]As used herein, a poly(aryl ether ketone) (PAEK) denotes any polymer comprising recurring units (RPAEK) comprising a Ar′—C(═O)—Ar* group, where Ar′ and Ar*, equal to or different from each other, are aromatic groups, the mol. % being based on the total number of moles of recurring units in the polymer. The recurring units (RPAEK) are selected from the group consisting of units of formulas (J-A) to (J-D) below:
where
[0045]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
[0046]j′ is independently zero or an integer ranging from 1 to 4.
[0047]In recurring unit (RPAEK), the respective phenylene moieties may independently have 1,2-, 1,4- or 1,3-linkages to the other moieties different from R′ in the recurring unit (RPAEK). Preferably, the phenylene moieties have 1,3- or 1,4-linkages, more preferably they have a 1,4-linkage.
[0048]In recurring units (RPAEK), j′ is preferably at each location zero so that the phenylene moieties have no other substituents than those linking the main chain of the polymer.
[0049]According to an embodiment, the PAEK is a poly(ether ether ketone) (PEEK).
[0050]As used herein, a poly(ether ether ketone) (PEEK) denotes any polymer comprising recurring units (RPEEK) of formula (J-A), based on the total number of moles of recurring units in the polymer:
[0051]where
[0052]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
[0053]j′, for each R′, is independently zero or an integer ranging from 1 to 4 (for example 1, 2, 3 or 4).
[0054]According to formula (J-A), each aromatic cycle of the recurring unit (RPEEK) may contain from 1 to 4 radical groups R′. When j′ is 0, the corresponding aromatic cycle does not contain any radical group R′.
[0055]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.
[0056]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.
[0057]According to an embodiment, j′ is zero for each R′. In other words, according to this embodiment, the recurring units (RPEEK) are according to formula (J′-A):
[0058]According to another embodiment of the present disclosure, a poly(ether ether ketone) (PEEK) denotes any polymer comprising at least 10 mol. % of the recurring units are recurring units (RPEEK) of formula (J-A″):
[0059]the mol. % being based on the total number of moles of recurring units in the polymer.
[0060]According to an embodiment of the present disclosure, at least 10 mol. % (based on the total number of moles of recurring units in the polymer), at least 20 mol. %, at least 30 mol. %, at least 40 mol. %, 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 formulas (J-A), (J′-A) and/or (J″-A).
[0061]The PEEK polymer can therefore be a homopolymer or a copolymer. If the PEEK polymer is a copolymer, it can be a random, alternate or block copolymer.
[0062]When the PEEK is a copolymer, it can be made of recurring units (R*PEEK), different from and in addition to recurring units (RPEEK), such as recurring units of formula (J-D):
[0063]where
[0064]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
[0065]j′, for each R′, is independently zero or an integer ranging from 1 to 4.
[0066]According to formula (J-D), each aromatic cycle of the recurring unit (R*PEEK) may contain from 1 to 4 radical groups R′. When j′ is 0, the corresponding aromatic cycle does not contain any radical group R′.
[0067]According to an embodiment, R′ is, at each location in formula (J-B) 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.
[0068]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):
[0069]According to another embodiment of the present disclosure, the recurring units (R*PEEK) are according to formula (J″-D):
[0070]According to an embodiment of the present disclosure, less than 90 mol. % (based on the total number of moles of recurring units in the polymer), less than 80 mol. %, less than 70 mol. %, less than 60 mol. %, 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-B), (J′-B), and/or (J″-B).
[0071]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 (RPEEK) of formulas (J-B), (J′-B) or (J″-B) (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 5/95, from 90/10 to 10/90, or from 85/15 to 15/85. 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.
[0072]Defects, end groups and monomers' impurities may be incorporated in very minor amounts in the polymer (PEEK) of the present disclosure, without undesirably affecting the performance of the polymer in the polymer composition (C1).
[0073]PEEK is commercially available as KetaSpire® PEEK from Solvay Specialty Polymers USA, LLC.
[0074]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 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).
[0075]According to one embodiment of the present disclosure, the PEEK polymer has a weight average molecular weight (Mw) ranging from 75,000 to 100,000 g/mol, for example from 77,000 to 98,000 g/mol, from 79,000 to 96,000 g/mol, from 81,000 to 95,000 g/mol, or from 85,000 to 94,500 g/mol (as determined by gel permeation chromatography (GPC) using phenol and trichlorobenzene (1:1) at 160° C., with polystyrene standards).
[0076]The powdered polymer material (M) of the invention may comprise PEEK in an amount of 55 to 95 wt. %, for example less than 60 to 90 wt. %, based on the total weight of M.
[0077]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.
[0078]In another embodiment, the PAEK is a poly(ether ketone ketone) (PEKK).
[0079]As used herein, a poly(ether ketone ketone) (PEKK) denotes a polymer comprising more than 50 mol. % of the recurring units of formulas (J-B1) and (J-B2), the mol. % being based on the total number of moles of recurring units in the polymer:
[0080]wherein
[0081]R1 and R2, at each instance, is independently selected from the group consisting of 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
[0082]i and j, at each instance, is an independently selected integer ranging from 0 to 4.
[0083]According to an embodiment, R1 and R2 are, at each location in formula (J-B2) and (J-B1) 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.
[0084]According to another embodiment, i and j are zero for each R1 and R2 group. According to this embodiment, the PEKK polymer comprises at least 50 mol. % of recurring units of formulas (J′-B1) and (J′-B2), the mol. % being based on the total number of moles of recurring units in the polymer:
[0085]According to an embodiment of the present disclosure, at least 55 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 PEKK are recurring units of formulas (J-B1) and (J-B2).
[0086]According to an embodiment of the present disclosure, in the PEKK polymer, the molar ratio of recurring units (J-B2) or/and (J′-B2) to recurring units (J-B1) or/and (J′-B1) is at least 1:1 to 5.7:1, for example at least 1.2:1 to 4:1, at least 1.4:1 to 3:1 or at least 1.4:1 to 1.86:1.
[0087]The PEKK polymer has preferably an inherent viscosity of at least 0.50 deciliters per gram (dL/g), as measured following ASTM D2857 at 30° C. on 0.5 wt./vol. % solutions in concentrated H2SO4 (96 wt. % minimum), for example at least 0.60 dL/g or at least 0.65 dL/g and for example at most 1.50 dL/g, at most 1.40 dL/g, or at most 1.30 dL/g.
[0088]PEKK is commercially available as NovaSpire® PEKK from Solvay Specialty Polymers USA, LLC
[0089]Polyphenylene Sulfide (PPS)
[0090]As used herein, a polyphenylene sulfide (PPS) denotes any polymer comprising at least 50 mol. % of recurring units (Rpps) of formula (U) (mol. % being based on the total number of moles of recurring units in the PPS polymer):
[0091]where
[0092]R is independently selected from the group consisting of halogen, C1-C12 alkyl groups, C7-C24 alkylaryl groups, C7-C24 aralkyl groups, C6-C24 arylene groups, C1-C12 alkoxy groups, and C6-C18 aryloxy groups, and i is independently zero or an integer from 1 to 4.
[0093]According to formula (U), the aromatic cycle of the recurring unit (RPPS) may contain from 1 to 4 radical groups R. When i is zero, the corresponding aromatic cycle does not contain any radical group R.
[0094]According to an embodiment of the present invention, the PPS polymer denotes any polymer comprising at least 50 mol. % of recurring units (RPPS) of formula (U′) where i is zero:
[0095]According to an embodiment of the present invention, the PPS polymer is such that at least 60 mol. %, at least 70 mol. %, at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, at least 99 mol. % of the recurring units in the PPS are recurring units (RPPS) of formula (U) or (U′). The mol. % are based are based on the total number of moles of recurring units in the PPS polymer.
[0096]According to an embodiment of the present invention, the PPS polymer is such that 100 mol. % of the recurring units are recurring units (RPPS) of formula (U) or (U′). According to this embodiment, the PPS polymer consists essentially of recurring units (RPPS) of formula (U) or (U′).
[0097]PPS is commercially available under the tradename Ryton® PPS from Solvay Specialty Polymers USA, LLC.
[0098]The melt flow rate (at 316° C. under a weight of 5 kg according to ASTM D1238, procedure B) of the PPS may be from 50 to 400 g/10 min, for example from 60 to 300 g/10 min or from 70 to 200 g/10 min.
[0099]Polyphtalamide (PPA)
[0100]As used herein, a polyphthalamide (PPA) denotes any polymer comprising at least 50 mol. % of recurring units (RPDA) (based on the total number of moles in the polymer) formed by the polycondensation of at least phthalic acid and at least aliphatic diamine. The phthalic acid can for example be selected from the group consisting of o-phthalic acid, isophthalic acid and terephthalic acid. The aliphatic diamine can for example be selected from the group consisting of hexamethylenediamine, 1,9-nonanediamine, 1,10-diaminodecane, 1,12-diaminododecane, 2-methyl-octanediamine, 2-methyl-1,5-pentanediamine, 1,4-diaminobutane. C6 diamines are prefered, in particular hexamethylenediamine.
[0101]Among polyphthalamides (PPA), polyterephthalamides (PTPA) are preferred. Polyterephthalamides are aromatic polyamides comprising at least 50 mol. % of recurring units (RPTPA) formed by the polycondensation of at least terephthalic acid (TPA) and at least one aliphatic diamine.
[0102]According to a first embodiment, the polyterephthalamides (PTPA) comprise at least 60 mol. %, at least 70 mol. %, at least 70 mol. %, at least 80 mol. %, at least 90 mol. %, at least 95. mol% or at least 99 mol. % of recurring units (RPTPA) formed by the polycondensation of at least terephthalic acid (TPA) and at least one aliphatic diamine. According to this embodiment, a preferred diamine is a C6 diamine and/or a C9 diamine and/or C10 diamine.
[0103]According to a second embodiment, the polyterephthalamides (PTPA) comprise recurring units formed by the polycondensation of terephthalic acid (PTA), isophthalic acid (IPA) and at least one aliphatic diamine. According to this embodiment, a preferred polyterephthalamide comprises at least 50 mol. % or consists essentially of recurring units formed by the polycondensation of terephthalic acid (PTA) and at least one aliphatic diamine and of recurring units formed by the polycondensation of isophthalic acid (IPA) and at least one aliphatic diamine, in a mole ratio ranging between 60:40 and 90:10 (mol. %).
[0104]According to a third embodiment, the polyterephthalamides (PTPA) comprise recurring units formed by the polycondensation reaction between terephthalic acid (TPA), at least one aliphatic diacid and at least one aliphatic diamine. The aliphatic diacid can for example be selected from the group consisting of adipic acid and sebacic acid. Adipic acid is preferred. According to this embodiment, a preferred polyterephthalamide comprises at least 50 mol. % or consists essentially of recurring units formed by the polycondensation of terephthalic acid (TPA) and at least one aliphatic diamine and of recurring units formed by the polycondensation of at least one aliphatic diacid and at least one aliphatic diamine, in a mole ratio ranging between 55:45 and 75:25 (mol. %).
[0105]According to a fourth embodiment, the polyterephthalamides (PTPA) comprise recurring units formed by the polycondensation of terephthalic acid (TPA), isophthalic acid (IPA), at least one aliphatic diacid and at least one aliphatic diamine. The aliphatic diacid can for example be selected from the group consisting of adipic acid and sebacic acid. Adipic acid is preferred. According to this embodiment, a preferred polyterephthalamide comprises at least 50 mol. % or consists essentially of recurring units (R1) formed by the polycondensation of terephthalic acid (TPA) and at least one aliphatic diamine, of recurring units (R2) formed by the polycondensation of isophthalic acid (IPA) and at least one aliphatic diamine, and of recurring units (R3) formed by the polycondensation of at least one aliphatic diacid and at least one aliphatic diamine. In this case, the mole ratio of recurring units (R1): (R2)+(R3) may range from 55:45 to 75:25 (mol %) and the mole ratio (R2):(R3) may range from 60:40 to 85:15.
[0106]The polyphtalamide (PPA) is semi-crystalline. The melting point of the PPA may be greater than 275° C., preferably greater than 290° C., more preferably greater than 305° C., and still more preferably greater than 320° C.
[0107]PPA is commercially available under the tradename Amodel® from Solvay Specialty Polymers USA, LLC.
[0108]Semi-Aromatic and Aromatic Polyesters (PE).
[0109]As used herein, a semi-aromatic or aromatic polyesters denotes any polymer comprising at least 50 mol. %, of recurring units (RPE) comprising at least one ester moiety of formula R—COO—R and at least one aromatic moiety.
[0110]The polyesters of the present invention may be obtained by polycondensation of an aromatic monomer (MA) comprising at least one hydroxyl group and at least one carboxylic acid group or by polycondensation of at least one monomer (MB) comprising at least two hydroxyl groups (a diol) and at least one monomer (MC) comprising at least two carboxylic acid groups (a dicarboxylic acid), with at least one of the monomers (MB) or (MC) comprising an aromatic moiety.
[0111]Non limitative examples of monomers (MA) include 4 hydroxybenzoic acid, 6-hydroxynaphthalene-2-carboxylic acid.
[0112]Non limitative examples of monomers (MB) include 1,4 cyclohexanedimethanol; ethylene glycol; 1,4-butanediol; 1,3-propanediol; 1,5 pentanediol, 1,6-hexanediol; and neopentyl glycol, while 1,4 cyclohexanedimethanol and neopentyl glycol are preferred.
[0113]Non limitative examples of monomers (MC) include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acids, cyclohexane dicarboxylic acid, succinic acid, sebacic acid, and adipic acid, while terephthalic acid and cyclohexane dicarboxylic acid are preferred.
[0114]Depending on the choice of monomers, polyesters (PE) can be either wholly semi-aromatic or aromatic. They can be copolymers or homopolymers.
[0115]According to an embodiment, when the polyester of the invented composition is a copolymer, at least 50 mol. %, at least 60 mol. %, at least 70 mol. %, at least 80 mol. %, or at least 90 mol. % of the recurring units are obtained through the polycondensation of terephthalic acid.
[0116]According to another embodiment, when the polyester of the invented composition is a copolymer, at least 50 mol. %, at least 60 mol. %, at least 70 mol. %, at least 80 mol. %, or at least 90 mol. % of the recurring units are obtained through the polycondensation of terephthalic acid with 1,4-cyclohexylenedimethanol.
[0117]When the polyester of the invented composition is a homopolymer, it may be selected from the group consisting of a polyethylene naphthalate (PEN), a poly(l,4 cyclohexylenedimethylene terephthalate) (PCT), and a Liquid Crystalline Polyester (LCP). It is preferably a PCT (i.e. a homopolymer obtained through the polycondensation of terephthalic acid with 1,4-cyclohexylenedimethanol).
[0118]The polyesters used herein have advantageously an intrinsic viscosity of from about 0.6 to about 2.0 dl/g as measured in a 60:40 phenol/tetrachloroethane mixture or similar solvent at about 30° C. Particularly suitable polyesters for this invention have an intrinsic viscosity of 0.6 to 1.4 dl/g.
[0119]The melting point of the PE may be greater than 270° C., and still more preferably greater than 280° C.
[0120]Polymer (P2)
[0121]According to an embodiment, the polymer (P2) is selected from the group consisting of poly(aryl ether sulfone) (PAES), poly(ether imide) (PEI), polycarbonate (PC), poly(phenyl ether) (PPE), amorphous polyamide with a glass transition temperature above 130° C. (for example Selar® PA 61/6T 70/30, Rilsan® Clear, Grilamid® TR, Grivory® G and Trogamid®), and amorphous aromatic polyester (for example U-Polymer® from Unitika).
[0122]When the polymer (P2) is a poly(aryl ether sulfone) (PAES), it is preferably a polyphenylsulfone (PPSU), a polyethersulfone (PES) or a polysulfone (PSU).
[0123]Poly(Aryl Ether Sulfone) (PAES)
[0124]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:
[0125]where[0126]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;[0127]h, for each R, is independently zero or an integer ranging from 1 to 4; and[0128]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.
[0129]According to an embodiment, Rj and Rk are methyl groups.
[0130]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′):
[0131]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′).
[0132]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.
[0133]According to an embodiment, the poly(aryl ether sulfone) (PAES) is a poly(biphenyl ether sulfone) (PPSU).
[0134]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.
[0135]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:
[0136]where[0137]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;[0138]h, for each R, is independently zero or an integer ranging from 1 to 4.
[0139]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.
[0140]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′):
[0141]According to another embodiment, the recurring units (RPPSU) are units of formula (L″):
[0142]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.
[0143]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″).
[0144]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):
[0145]The poly(biphenyl ether sulfone) (PPSU) can also be a blend of a PPSU homopolymer and at least one PPSU copolymer, as described above.
[0146]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.
[0147]PPSU is commercially available as Radel® PPSU from Solvay Specialty Polymers USA, L.L.C.
[0148]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).
[0149]According to one embodiment, the powdered polymer material