Patent Application
20240343963
Polymer compositions are provided that are thermally conductive and electrically resistive. Articles made therefrom are also provided. In particular, the present polymer compositions comprise a thermoplastic polymer and a combination of a thermally conductive filler and an electrically conductive carbon fiber.
Polymer compositions are used in many applications, including in motors, batteries, LED's, electronic circuit boards, etc. In many of these, the polymer composition may desirably function to help dissipate heat away from any heat generating component. While thermal conductivity may be desired, electrical conductivity is often contraindicated and polymer compositions used in such applications are expected to have volume resistivities of at least 1E+8 Ω·cm.
Purely thermally conductive fillers have typically been used in polymer compositions intended for use in these environments. However, polymer compositions including only thermally conductive fillers have limited in- and through-plane thermal conductivity. This may be due to thermal conductivity limitations intrinsic to the filler(s) and/or thermal resistance at polymer/filler interfaces. As a result, the use of higher concentrations of purely thermally conductive fillers in polymer compositions in order to achieve a desired conductivity may not have the expected or desired impact.
A need exists for polymer compositions that exhibit both thermal conductivity and electrical resistance, desirably without compromising the mechanical performance of the polymer composition.
A polymer composition is provided, comprising:
Articles comprising the polymer composition are also provided, for example selected from the group consisting of a structural or functional part of i) an electronic device, ii) an automobile, iii) a motor, iv) a battery, v) an LED, vi) an electronic board, vii) an electronic vehicle charging station, viii) a vacuum or vacuum system, etc.
There are provided polymer compositions comprising a thermoplastic polymer, at least one thermally conductive filler, and an electrically conductive carbon fiber. Significantly, the polymer compositions are substantially free of glass fibers. It has surprisingly been found that the polymer compositions described herein have significantly improved thermal conductivity relative to analogous polymer compositions in which the carbon fiber is replaced by glass fiber. It was also surprisingly found that, even though carbon fiber has a significantly higher electrical conductivity relative to glass fiber, the polymer compositions did not have any appreciable loss of volume resistivity relative to analogous polymer compositions in which carbon fiber is replaced by glass fiber. Further, the tensile and flexural moduli of the polymer compositions comprising carbon fibers are surprisingly increased relative to analogous polymer compositions in which carbon fibers are replaced with glass fibers.
As used herein, polymer compositions that are “substantially free” of an indicated component (e.g., glass fiber) have a concentration of the indicated component that is less than 5 wt. %, or 4 wt. %, or 3 wt. %, or 2 wt. % or 1 wt. %. As used herein, wt. % is relative to the total weight of the polymer composition, unless explicitly indicated otherwise.
Any description, even though described in relation to a specific embodiment, is applicable to and interchangeable with other embodiments of the present disclosure. Further, any element or component recited in a list of elements or components may be omitted from such list.
Any recitation of numerical ranges by endpoints includes all numbers and subranges subsumed within the recited ranges as well as the endpoints of the range.
As used herein, the mol % of a particular recurring unit is determined relative to the total number of recurring units in the indicated polymer, unless explicitly indicated otherwise.
The amount of energy in the form of heat required to bring about a change of state of a thermoplastic polymer from the solid to the liquid form is the heat of fusion (“ΔHf”), and the temperature at which this change of state occurs is called the melting temperature (Tm). ΔHf and Tm can be measured according to ASTM D3418.
The glass transition temperature (Tg) is the temperature at which an amorphous material (or an amorphous region within a semicrystalline material) transitions from a hard and relatively brittle state into a viscous or rubbery state. Tg can be measured according to ASTM E1356, “Standard Test Method for Assignment of the Glass Transition Temperatures by Differential Scanning Calorimetry.”
The terms “halogen” or “halo” include fluorine, chlorine, bromine and iodine.
Unless specifically limited otherwise, the term “alkyl”, as well as derivative terms such as “alkoxy”, “acyl” and “alkylthio”, as used herein include within their scope straight chain, branched chain and cyclic moieties. Examples of alkyl groups are methyl, ethyl, 1-methylethyl, propyl, 1,1-dimethylethyl and cyclopropyl.
Similarly, unless specifically stated otherwise, the term “aryl” refers to a phenyl, indanyl or naphthyl group. The aryl group may comprise one or more alkyl groups, and if this is the case, may be referred to as “alkylaryl.” An aromatic group, for example, may be substituted with one or more C1-C6 alkyl groups, such as methyl or ethyl.
An aryl group may also comprise one or more heteroatoms, e.g., N, O, or S, and in such instances may appropriately be referred to as a “heteroaryl” group. Such heteroaromatic rings may also be fused to other aromatic systems. Examples of heteroaromatic rings include, but are not limited to, furanyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, isoxazolyl, oxazolyl, thiazolyl, isothiazolyl, pyridyl, pyridazyl, pyrimidyl, pyrazinyl and triazinyl ring structures.
Unless specifically stated otherwise, each alkyl, aryl and heteroaryl group may be unsubstituted or substituted with one or more substituents selected from but not limited to halogen, hydroxy, sulfo, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkylthio, C1-C6 acyl, formyl, cyano, C6-C15 aryloxy or C6-C15 aryl, provided that the substituents are sterically compatible and the rules of chemical bonding and strain energy are satisfied.
The polymer composition comprises a thermoplastic polymer. Generally, any thermoplastic polymer may find benefit from application of the principles described herein, but those contemplated for use in applications wherein high heat conductivity and electrical resistivity are desired are of particular interest. Suitable thermoplastic polymers for use in the polymer composition include, but are not limited to, a poly(arylene sulfide), a polyamide, a poly(aryl ether sulfone), a poly(aryl ether ketone), a liquid crystal polymer, and/or a polyester.
In some embodiments, the polymer composition comprises at least 15 wt. %, at least 20 wt. %, or at least 25 wt. % of the thermoplastic polymer. In some embodiments, the polymer composition comprises no more than 60 wt. %, no more than 55 wt. %, or no more than 50 wt. % of the thermoplastic polymer. In some embodiments, the polymer composition comprises from 15 wt. % to 60 wt. %, from 20 wt. % to 55 wt. %, or from 25 wt. % to 50 wt. % of the thermoplastic polymer.
In some embodiments, the polymer composition can include a plurality of thermoplastic polymers, including but not limited to those recited above. In such embodiments, the total concentration of thermoplastic polymers is within the ranges given above.
In some embodiments, the thermoplastic polymer is semi-crystalline. As used herein, a semi-crystalline polymer has a heat of fusion (“ΔHf”) of at least 5 J/g. As such, in some embodiments, the thermoplastic polymer has a ΔHf (at a heating rate of 20° C./min) of at least 5 J/g, at least 10 J/g, at least 20 J/g, or at least 25 J/g. In some embodiments, the thermoplastic polymer has a ΔHf of no more than 90 J/g, no more than 80 J/g, no more than 70 J/g or no more than 60 J/g. In some embodiments, the thermoplastic polymer has a ΔHf of from 5 J/g to 90 J/g, from 10 J/g to 80 J/g, from 20 J/g to 70 J/g or from 25 J/g to 60 J/g.
In some embodiments, the thermoplastic polymer is a poly(arylene sulfide) (PAS). As used herein, a poly(arylene sulfide) refers to any polymer including at least 50 mol % of a recurring unit (RPAS) of formula (I):
—[—Ar—S—]— (I)
In some embodiments, recurring unit (RPAS) is represented by a formula selected from the following group of formulae:
In recurring units (RPAS), respective phenylene moieties may independently have 1,2-, 1,3- or 1,4-linkages to moieties other than R. In some embodiments, the phenylene moieties each independently have 1,3 or 1,4-linkages to moieties other than R. Preferably, the phenylene moieties have 1,4-linkages to moieties other than R.
In one embodiment, —Ar— of formula (I) is a phenyl group, so that the recurring unit (RPAS) is represented by formula (II). Preferably, —Ar— of formula (I) is represented by Formula (II) wherein i is 0 and the phenylene moieties have 1,4-linkages to moieties other than R so that recurring unit (RPAS) is represented by the following formula (II′):
In such embodiments, the poly(arylene sulfide) is a polyphenylene sulfide.
In some embodiments, the concentration of recurring unit (RPAS) of formulae (II), (II′), (Ill) and/or (IV) in the poly(arylene sulfide) is at least 60 mol %, at least 70 mol %, at least 80 mol %, at least 90 mol %, at least 95 mol %, at least 98 mol %, at least 99 mol % or at least 99.9 mol %. In such embodiments, the poly(arylene sulfide) consists essentially of recurring unit (RPAS). In other embodiments, the concentration of recurring unit (RPAS) of formulae (II), (II′), (III) and/or (IV) in the poly(arylene sulfide) is 100 mol % and in these embodiments, the poly(arylene sulfide) consists of recurring unit (RPAS).
In some embodiments, the poly(arylene sulfide) has an weight average molecular weight (“Mw”) of at least 10,000 g/mol, at least 20,000 g/mol, at least 25,000 g/mol, at least 30,000 g/mol, or at least 35,000 g/mol. In some embodiments, the poly(arylene sulfide) has an Mw of no more than 150,000 g/mol, no more than 100,000 g/mol, no more than 90,000 g/mol, no more than 85,000 g/mol, or no more than 80,000 g/mol. In some embodiments, the poly(arylene sulfide) has an Mw of from 10,000 g/mol to 150,000 g/mol, from 20,000 g/mol to 100,000 g/mol, from 25,000 g/mol to 90,000 g/mol, from 30,000 g/mol to 85,000 g/mol, or from 35,000 g/mol to 80,000 g/mol. The Mw of poly(arylene sulfide) can be measured with gel permeation chromatography (“GPC”) using a 4-chloronapthalene standard.
In some embodiments, the poly(arylene sulfide) has a Tm of at least 200° C., at least 220° C., at least 240° C., or at least 250° C. In some embodiments, the poly(arylene sulfide) (PAS) has a Tm of no more 350° C., no more than 320° C. no more than 300° C. or no more than 285° C. In some embodiments, the poly(arylene sulfide) (PAS) has a Tm of from 200° C. to 350° C., from 220° C. to 320° C., from 240° C. to 300° C., or from 250° C. to 285° C.
The melt flow rate (at 316° C. under a weight of 5 kg according to ASTM D1238, procedure B) of poly(phenylene sulfide) (a poly(arylene sulfide) according to formula (II′)) may be from 50 to 400 g/10 min, from 60 to 300 g/10 min or from 70 to 200 g/10 min.
Poly(arylene sulfide) and poly(phenylene sulfide) can be prepared by known methods.
In some embodiments, the thermoplastic polymer is a polyamide (PA). A polyamide refers to a polymer including at least 50 mol % of recurring units having at least one amide bond (—CONH—). In some embodiments, the polyamide includes recurring units (RPA) of formula (V):
In some embodiments, R3 in formula (V) is a phenyl and the polyamide is a polyphthalamide in accordance with formula (VI):
In some embodiments, the polyamide includes at least 60 mol %, at least 70 mol %, at least 80 mol %, at least 90 mol %, at least 95 mol %, at least 98 mol %, at least 99 mol % or at least 99.9 mol % percent of recurring units (RPA) according to formulae (V) and/or (VI). In such embodiments, the polyamide consists essentially of recurring units (RPA) of formula (V) and/or (VI). In other embodiments, the polyamide is such that 100 mol % of the recurring units are recurring units (RPA) according to formulae (V) and/or (VI). According to such embodiments, the polyamide consists of recurring units (RPA) of formula (V) and/or (VI).
In some embodiments, the polyamide has an Mw of at least 15,000 g/mol, at least 20,000 g/mol, at least 25,000 g/mol, at least 30,000 g/mol, or at least 35,000 g/mol. In some embodiments, the polyamide has an Mw of no more than 150,000 g/mol, no more than 100,000 g/mol, no more than 90,000 g/mol, no more than 85,000 g/mol, or no more than 80,000 g/mol. In some embodiments, the polyamide has an Mw of from 15,000 g/mol to 150,000 g/mol, from 20,000 g/mol to 100,000 g/mol, from 25,000 g/mol to 90,000 g/mol, from 30,000 g/mol to 85,000 g/mol, or from 35,000 g/mol to 80,000 g/mol. The Mw of polyamide can be measured with gel permeation chromatography (“GPC”) using polymethylmethacrylate standards.
In some embodiments, the polyamide has a Tm of at least 200° C., at least 220° C., at least 240° C., or at least 250° C. In some embodiments, the polyamide has a Tm of no more 370° C., no more than 360° C., no more than 350° C., or no more than 340° C. In some embodiments, the polyamide has a Tm of from 200° C. to 370° C., from 220° C. to 360° C., from 240° C. to 350° C., or from 250° C. to 340° C.
Polyamides and polyphthalamides can be prepared by known methods.
In some embodiments, the thermoplastic polymer is a poly(aryl ether sulfone) (PAES). Poly(aryl ether sulfone)s include, but are not limited to, polysulfone, polyphenylsulfone and polyether sulfone.
A poly(aryl ether sulfone) refers to any polymer including at least 50 mol. % of a recurring units (RPAES) of formula (VII):
—C(R2)(R2)— (VIII)
T is preferably a bond (i.e., the polyarylether sulfone is a polyphenylsulfone), a sulfone group (i.e., the polyarylether sulfone is a polyethersulfone) or a group according to formula (VIII) in which each R2 is a methyl group (i.e., the polyarylether sulfone is a polysulfone).
In recurring units (RPAES), respective phenylene moieties may independently have 1,2-, 1,3- or 1,4-linkages to moieties other than R. In some embodiments, the phenylene moieties each independently have 1,3 or 1,4-linkages to moieties other than R. Preferably, the phenylene moieties have 1,4-linkages to moieties other than R.
In some embodiments, at least 60 mol %, at least 70 mol %, at least 80 mol %, at least 90 mol %, at least 95 mol %, at least 98 mol %, at least 99 mol % or at least 99.9 mol % of the recurring units in the poly(aryl ether sulfone) are recurring units (RPAES). In such embodiments, the poly(aryl ether sulfone) consists essentially of recurring units (RPAES). In other embodiments, the poly(aryl ether sulfone) is such that 100 mol. % of the recurring units are recurring units (RPAES). According to such embodiments, the poly(aryl ether sulfone) consists of recurring units (RPAES).
The poly(aryl ether sulfone) may have an Mw of from 30,000 g/mol to 80,000 g/mol, for example from 35,000 g/mol to 75,000 g/mol or from 40,000 g/mol to 70,000 g/mol. The Mw of poly(aryl ether sulfone) 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.
In some embodiments, the poly(aryl ether sulfone) has a Tg of at least 150° C., at least 160° C., at least 170° C., or at least 180° C. In some embodiments, the poly(aryl ether sulfone) has a Tg of no more 270° C., no more than 260° C., no more than 250° C., or no more than 240° C. In some embodiments, the poly(aryl ether sulfone) has a Tg of from 150° C. to 270° C., from 160° C. to 260° C., from 170° C. to 250° C., or from 170° C. to 240° C.
Poly(aryl ether sulfone) can be prepared by known methods.
In some embodiments, the thermoplastic polymer is a poly(aryl ether sulfone) and the poly(aryl ether sulfone) is a polysulfone (PSU). As used herein, a polysulfone refers to any polymer including at least 50 mol % of a recurring unit (RPSU) of formula (VII-A):
In one embodiment, i is 0 for each R in formula (VII-A). According to this embodiment, the recurring units (RPSU) are units of formula (VII-B):
In recurring units (RPSU), respective phenylene moieties may independently have 1,2-, 1,3- or 1,4-linkages to moieties other than R. In some embodiments, the phenylene moieties each independently have 1,3 or 1,4-linkages to moieties other than R. Preferably, the phenylene moieties have 1,4-linkages to moieties other than R.
In some embodiments, at least 60 mol %, at least 70 mol %, at least 80 mol %, at least 90 mol %, at least 95 mol %, at least 98 mol %, at least 99 mol % or at least 99.9 mol % of the recurring units in the polysulfone are recurring units (RPSU) of formula (VII-A) and/or formula (VII-B). In such embodiments, the polysulfone consists essentially of recurring units (RPSU) of formula (VII-A) and/or formula (VII-B). In other embodiments, the polysulfone is such that 100 mol. % of the recurring units are recurring units (RPSU) of formula (VII-A) and/or formula (VII-B). According to such embodiments, the polysulfone consists of recurring units (RPSU) of formula (VII-A) and/or formula (VII-B).
In some embodiments, the Mw of the polysulfone is 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. The Mw of polysulfone 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.
In some embodiments, the polysulfone has a Tg of at least 150° C., at least 160° C., at least 170° C., or at least 180° C. In some embodiments, the polysulfone has a Tg of no more 270° C., no more than 260° C., no more than 250° C., or no more than 240° C. In some embodiments, the polysulfone has a Tg of from 150° C. to 270° C., from 160° C. to 260° C., from 170° C. to 250° C., or from 170° C. to 240° C.
Polysulfone can be prepared by known methods.
In some embodiments, the thermoplastic polymer is a poly(aryl ether sulfone) and the poly(aryl ether sulfone) is a polyphenylsulfone (PPSU). As used herein, a polyphenylsulfone refers to any polymer including at least 50 mol % of a recurring unit (RPPSU) of formula (VII-C):
In some embodiments, at least 60 mol %, at least 70 mol %, at least 80 mol %, at least 90 mol %, at least 95 mol %, at least 98 mol %, at least 99 mol % or at least 99.9 mol % of all of the recurring units in the polyphenylsulfone are recurring units (RPPSU). In such embodiments, the polyphenylsulfone consists essentially of recurring units (RPPSU). In other embodiments, the polyphenylsulfone is such that 100 mol. % of the recurring units are recurring units (RPPSU). According to such embodiments, the polyphenylsulfone consists of recurring units (RPPSU).
In some embodiments, the polyphenylsulfone has an Mw of at least 20,000 g/mol, at least 30,000 g/mol, or at least 40,000 g/mol. In some embodiments, the polyphenylsulfone has an Mw of no more than 100,000 g/mol, no more than 90,000 g/mol, or no more than 80,000 g/mol. In some embodiments, the polyphenylsulfone has an Mw of from 20,000 g/mol to 100,000 g/mol, from 30,000 g/mol to 90,000 g/mol, or from 40,000 g/mol to 80,000 g/mol. The Mw of polyphenylsulfone can be measured with gel permeation chromatography (“GPC”) using polystyrene standards.
In some embodiments, the polyphenylsulfone has a Tg of at least 150° C., at least 160° C., at least 170° C., or at least 180° C. In some embodiments, the polyphenylsulfone has a Tg of no more 270° C., no more than 260° C., no more than 250° C., or no more than 240° C. In some embodiments, the polyphenylsulfone has a Tg of from 150° C. to 270° C., from 160° C. to 260° C., from 170° C. to 250° C., or from 170° C. to 240° C.
Polyphenylsulfone can be prepared by known methods.
In some embodiments, the thermoplastic polymer is a poly(aryl ether sulfone) and the poly(aryl ether sulfone) is a polyethersulfone (PES). As used herein, a polyethersulfone refers to any polymer including at least 50 mol % of a recurring unit (RPES) of formula (VII-D):
In some embodiments, at least 60 mol %, at least 70 mol %, at least 80 mol %, at least 90 mol %, at least 95 mol %, at least 98 mol %, at least 99 mol % or 99.9 mol % of the recurring units in the polyethersulfone are recurring units (RPES). In such embodiments, the polyethersulfone consists essentially of recurring units (RPES).
In other embodiments, the polyethersulfone is such that 100 mol. % of the recurring units are recurring units (RPES). According to such embodiments, the polyethersulfone consists of recurring units (RPES).
In some embodiments, the polyethersulfone has an Mw of at least 20,000 g/mol, at least 30,000 g/mol, or at least 40,000 g/mol. In some embodiments, the polyethersulfone has an Mw of no more than 100,000 g/mol, no more than 90,000 g/mol, or no more than 80,000 g/mol. In some embodiments, the polyethersulfone has an Mw of from 20,000 g/mol to 100,000 g/mol, from 30,000 g/mol to 90,000 g/mol, or from 40,000 g/mol to 80,000 g/mol. The Mw of polyethersulfone can be measured with gel permeation chromatography (“GPC”) using polystyrene standards.
In some embodiments, the polyethersulfone has a Tg of at least 150° C., at least 160° C., at least 170° C., or at least 180° C. In some embodiments, the polyethersulfone has a Tg of no more 270° C., no more than 260° C., no more than 250° C., or no more than 240° C. In some embodiments, the polyethersulfone has a Tg of from 150° C. to 270° C., from 160° C. to 260° C., from 170° C. to 250° C., or from 170° C. to 240° C.
Polyethersulfone can be prepared by known methods.
In some embodiments, the thermoplastic polymer is a poly(aryl ether ketone) (PAEK).
A poly(aryl ether ketone) refers to any polymer including at least 50 mol % of recurring units (RPAEK) comprising a Ar′—C(═O)—Ar* group, where Ar′ and Ar* are the same, or different, aromatic groups.
As used herein, recurring units (RPAEK) are recurring units of formulae (VIII)-(XI):
In recurring unit (RPAEK), the respective phenylene moieties may independently have 1,2-, 1,3- or 1,4-linkages to the other moieties different from R in the recurring unit (RPAEK). In some embodiments, the phenylene moieties each independently have 1,3 or 1,4-linkages to moieties other than R. Preferably, the phenylene moieties have 1,4-linkages to moieties other than R.
In some embodiments of recurring units (RPAEK), i is 0 for each R in formulae (VIII)-(XI). According to this embodiment, the recurring units (RPAEK) are represented by formulae (VIII-A) to (XI-A):
A polymer of which at least 50% of the recurring units are recurring units (RPAEK) of formulae (VIII), (XI), (VIII-A) and/or (XI-A) are also understood by those of ordinary skill in the art to belong to the genus of poly(ether ether ketones) (PEEK).
According to an embodiment, at least 60 mol %, at least 70 mol %, at least 80 mol %, at least 90 mol %, at least 95 mol %, at least 98 mol %, at least 99 mol %, or at least 99.9 mol % of the recurring units in the poly(aryl ether ketone) are recurring units (RPAEK) of formula (VIII), formula (IX), formula (X) and/or formula (XI). In such embodiments, the poly(aryl ether ketone) consists essentially of recurring units (RPAEK) of formula (VIII), formula (IX), formula (X) and/or formula (XI).
In other embodiments, the poly(aryl ether ketone) is such that 100 mol. % of the recurring units are recurring units (RPAEK) of formula (VIII), formula (IX), formula (X) and/or formula (XI). According to such embodiments, the poly(aryl ether ketone) consists of recurring units (RPAEK) of formula (VIII), formula (IX), formula (X) and/or formula (XI).
In some embodiments, the poly(aryl ether ketone) has an Mw of at least 30,000 g/mol, at least 40,000 g/mol, or at least 50,000 g/mol. In some embodiments, the poly(aryl ether ketone) has an Mw of no more than 200,000 g/mol, no more than 175,000 g/mol, or no more than 150,000 g/mol. In some embodiments, the poly(aryl ether ketone) has an Mw of from 30,000 g/mol to 200,000 g/mol, from 40,000 g/mol to 175,000 g/mol, of from 50,000 g/mol to 150,000 g/mol. The Mw of poly(aryl ether ketone) can be measured with gel permeation chromatography (“GPC”) using polymethylmethacrylate standards.
In some embodiments, the poly(aryl ether ketone) has a Tm of at least 270° C., at least 280° C., at least 290° C., or at least 300° C. In some embodiments, the poly(aryl ether ketone) has a Tm of no more 400° C., no more than 390° C., no more than 380° C., or no more than 370° C. In some embodiments, the poly(aryl ether ketone) has a Tm of from 270° C. to 400° C., from 280° C. to 390° C., from 290° C. to 380° C., or from 280° C. to 370° C.
Poly(aryl ether ketone) and poly(ether ether ketone) can be prepared by known methods.
In some embodiments, the thermoplastic polymer is a liquid crystal polymer. Liquid crystal polymers are formed from the polycondensation of the following monomers: terephthalic acid, an aromatic diol, a first aromatic dicarboxylic acid distinct from terephthalic acid, and an aromatic hydroxycarboxylic acid.
In some embodiments, the aromatic diol is represented by a formula selected from formulae (XII) and (XIII):
HO—Ar1—OH (XII)
HO—Ar2-T1-Ar3—OH (XIII)
In some embodiments, the aromatic diol is selected from the group consisting of 1,3-dihydroxybenzene, 1,4-dihydroxybenzene, 2,5-biphenyldiol, 4,4′-biphenol, 4,4′-(propane-2,2-diyl)diphenol, 4,4′-(ethane-1,2-diyl)diphenol, 4,4′-methylenediphenol, bis(4-hydroxyphenyl)methanone, 4,4′-oxydiphenol, 4,4′-sulfonyldiphenol, 4,4′-thiodiphenol, naphthalene-2,6-diol, and naphthalene-1,5-diol. Preferably, the aromatic diol is 4,4′-biphenol.
In some embodiments, the first aromatic dicarboxylic acid is independently represented by a formula selected from formulae (XIV) and (XV):
HOOC—Ar1—COOH (XIV)
HOOC—Ar2-T2-Ar3—COOH (XV)
In some embodiments, the first aromatic dicarboxylic acid is selected from the group consisting of isophthalic acid, 4,4′-biphenyldicarboxylic acid, 4,4′-oxydibenzoic acid, 4,4′-(ethylenedioxy)dibenzoic acid, 4,4′-sulfanediyldibenzoic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, and naphthalene-2,3-dicarboxylic acid. Preferably the first aromatic dicarboxylic acid is selected from the group consisting of isophthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, and naphthalene-2,3-dicarboxylic acid. Most preferably, the first aromatic dicarboxylic acid is isophthalic acid.
In some embodiments, the aromatic hydroxycarboxylic acid is represented by a formulae selected from formulae (XVI) and (XVII):
HO—Ar1—COOH (XVI)
HO—Ar2—Ar3—COOH (XVII)
In some embodiments, the aromatic hydroxycarboxylic acid is selected from the group consisting of 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 6-hydroxy-1-naphthoic acid, 2-hydroxy-1-naphthoic acid, 3-hydroxy-2-naphthoic acid, 1-hydroxy-2-naphthoic acid, 5-hydroxy-1-naphthoic acid, and 4′-hydroxy-[1,1′-biphenyl]-4-carboxylic acid. Preferably, the aromatic hydroxycarboxylic acid is selected from the group consisting of 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 6-hydroxy-1-naphthoic acid, 2-hydroxy-1-naphthoic acid, 3-hydroxy-2-naphthoic acid, 1-hydroxy-2-naphthoic acid, and 5-hydroxy-1-naphthoic acid. Most preferably, the aromatic hydroxycarboxylic acid is 4-hydroxybenzoic acid.
As used herein, an LCP refers to any polymer formed from the aforementioned monomers and having at least 50% of recurring units (RLCP) of formulae (XVIII)-(XI):
—[—O—Ar1—O—]— (XIX)
—[—O—Ar2-T1-Ar3—O—]— (XX)
—[—OC—Ar1—CO—]— (XXI)
—[—OC—Ar2-T2-Ar3—CO—]— (XXII)
—[—O—Ar1—CO—]— (XXIII)
—[—O—Ar2—Ar3—CO—]— (XXIV)
One of ordinary skill in the art will recognize that RLCP according to formula (XVIII) is formed from terephthalic acid; RLCP according to formulae (XIX) and (XX) are respectively formed from monomers according to formulae (XII) and (XIII); RLCP according to formulae (XXI) and (XXII) are respectively formed from monomers according to formulae (XIV) and (XV); and RLCP according to formulae (XXIII) and (XXIV) are formed from monomers according to formulae (XVI) and (XVII). As such, the selection of Ar1 to Ar3, T1 and T2 for the monomers in formulae (XII) to (XVII) also selects Ar1 to Ar3, T1 and T2 for recurring units RLCP according to formulae (XIX) to (XIXV). Preferably, recurring units RLCP according to formula (XVIII) are formed by the polycondensation of terephthalic acid, recurring units RLCP according to formulae (XIX) and (XX) are formed by the polycondensation of 4,4′-biphenol, recurring units RLCP according to formulae (XXI) and (XXII) are formed by the polycondensation of isophthalic acid and recurring units RLCP according to formulae (XXIII) and (XXIV) are formed by the polycondensation of 4-hydroxybenzoic acid.
In some embodiments, the total concentration of recurring units RLCP according to formulae (XVIII) to (XXIV) is 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 98 mol %, at least 99 mol %, or at least 99.9 mol %.
In some embodiments, the concentration of recurring units RLCP according to formula (XVIII) is from 5 mol % to 30 mol %, preferably from 10 mol % to 20 mol %. In some embodiments, the concentration of recurring units RLCP according to formulae (XIX) and/or (XX) is from 10 mol % to 30 mol %, preferably from 15 mol % to 25 mol %. In some embodiments, the concentration of recurring units RLCP according to formulae (XXI) and (XXII) is from 1 mol % to 20 mol %, preferably from 1 mol % to 10 mol %. In some embodiments, the concentration of recurring units RLCP according to formulae (XXIII) and (XXIV) is from 35 mol % to 80 mol %, preferably from 45 mol % to 75 mol %, most preferably from 50 mol % to 70 mol %.
In some embodiments, the LCP has an Mw of at least 20,000 g/mol. In some embodiments, the LCP has an Mw of no more than 80,000 g/mol. In some embodiments, the LCP has an Mw of from 20,000 g/mol to 80,000 g/mol. The Mw can be determined by gel permeation chromatography (GPC) according to ASTM D5296 and using hexafluoroisopropanol solvent and poly(methyl methacrylate) standard.
In some embodiments, the LCP has a Tm of at least 220° C., at least 250° C., or at least 280° C. In some embodiments, the LCP has a Tm of no more than 420° C., no more than 390° C., or no more than 360° C. In some embodiments, the LCP has a Tm of from 220° C. to 420° C., from 250° C. to 390° C., or from 280° C. to 360° C.
Liquid crystal polymers can be prepared by known methods.
In some embodiments, the thermoplastic polymer is a polyester. As used herein, a polyester refers to any polymer including at least 50 mol % of recurring units (RPE) which contains an ester group (—C(═O)—O—). In some embodiments, the polyester includes recurring units (RPE) of formula (XXV):
In recurring units (RPE), respective phenylene moieties may independently have 1,2-, 1,3- or 1,4-linkages to moieties other than R. In some embodiments, the phenylene moieties each independently have 1,3 or 1,4-linkages to moieties other than R. Preferably, the phenylene moieties have 1,4-linkages to moieties other than R.
In some embodiments, i and j are each zero, T is a bond, and/or n is 1, 2 or 4. In some such embodiments, the polyester polymer is polytrimethylene terephthalate (i and j are 0, T is a bond and n is 1); polyethylene terephthalate (i and j are 0, T is a bond and n is 2); or polybutylene terephthalate (i and j are 0, T is a bond and n is 4).
In some embodiments, at least 60 mol %, at least 70 mol %, at least 80 mol %, at least 90 mol %, at least 95 mol %, at least 98 mol %, at least 99 mol % or at least 99.9 mol % of the recurring units in the polyester are recurring units (RPE). In such embodiments, the polyester consists essentially of recurring units (RPE). In other embodiments, the polyester is such that 100 mol. % of the recurring units are recurring units (RPE). According to such embodiments, the polyester consists of recurring units (RPE).
In some embodiments, the polyester has an Mw of at least 10,000 g/mol, at least 20,000 g/mol, or at least 30,000 g/mol. In some embodiments, the polyester has an Mw of no more than 100,000 g/mol, no more than 90,000 g/mol, or no more than 80,000 g/mol. In some embodiments, the polyester has an Mw of from 10,000 g/mol to 100,000 g/mol, from 20,000 g/mol to 90,000 g/mol, of from 30,000 g/mol to 80,000 g/mol. The Mw of polyester can be measured with gel permeation chromatography (“GPC”) using polymethylmethacrylate standards.
In some embodiments, the polyester has a Tm of at least 250° C., preferably at least 260° C., more preferably at least 270° C. and most preferably at least 280° C. In some embodiments, the polyester polymer has a melting point of at most 350° C., preferably at most 340° C., more preferably at most 330° C. and most preferably at most 320° C. In some embodiments, the polyester has a Tm of from 250° C. to 350° C., from 260° C. to 340° C., from 270° C. to 330° C., or from 280° C. to 320° C.
Polyesters can be prepared by known methods.
The polymer composition comprises a thermally conductive filler. As used herein, a thermally conductive filler has a thermal conductivity of at least 0.5 W/(m·K), at least 2 W/(m·K), or at least 4 W/(m·K), as measured by ASTM E1461-13. Useful thermally conductive fillers include, but are not limited to, inorganic oxides and nitrides including, but not limited to, aluminum oxide (alumina), zinc oxide, magnesium oxide and silicon dioxide, boron nitride, aluminum nitride and silicon nitride; metal and metal alloys; silicon carbide powder; zinc sulfide, magnesium carbonate and calcium fluoride powder; and the like.
Preferably, thermally conducting fillers are selected from the group consisting of inorganic oxides or nitrides, and more preferably, thermally conducting fillers are selected from magnesium oxide, zinc oxide, boron nitride and combinations of these. In some embodiments, boron nitride is particularly preferred.
In some embodiments, the polymer composition comprises at least 5 wt. %, at least 10 wt. %, or at least 15 wt. % of the thermally conductive filler. In some embodiments, the polymer composition comprises no more than 50 wt. %, no more than 45 wt. % or no more than 40 wt. % of the thermally conductive filler. In some embodiments, the polymer composition comprises from 5 wt. % to 50 wt. %, or from 10 wt. % to 45 wt. %, or from 15 wt. % to 40 wt. % of the thermally conductive filler.
The polymer composition comprises an electrically conductive carbon fiber. As used herein an electrically conductive carbon fiber has a resistivity of less than 20 micro-ohm m, less than 10 micro-ohm-m, less than 5 micro-ohm-m, or less than 3 micro-ohm-m.
In some embodiments, the polymer composition comprises at least 5 wt. %, or at least 10 wt. %, or at least 15 wt. % of the electrically conductive carbon fiber. In some embodiments, the polymer composition comprises no more than 40 wt. %, or no more than 35 wt. %, or no more than 30 wt. % of the electrically conductive carbon fiber. In some embodiments, the polymer composition comprises from 5 wt. % to 40 wt. %, or from 10 wt. % to 35 wt. %, or from 15 wt. % to 30 wt. % of the electrically conductive carbon fiber.
The carbon fiber is generally cylindrical and is characterized by a length (along the long axis of the carbon fiber) and a cross-sectional diameter (referred to simply as diameter) that is perpendicular to the long axis.
In some embodiments, the carbon fiber has an average length of at least 5 μm, at least 50 μm, at least 100 μm, at least 150 μm or at least 175 μm. In some embodiments, the carbon fiber has an average length of no more than 400 μm, no more than 350 μm, no more than 300 μm, no more 250 μm or no more than 225 μm. In some embodiments, the carbon fiber has an average length of from 5 μm to 400 μm, from 50 μm to 350 μm, from 100 μm to 300 μm, from 150 μm to 250 μm or from 175 μm to 225 μm.
In some embodiments, the carbon fiber has an average diameter of at least 1 μm, at least 5 μm, at least 7 μm or at least 8 μm. In some embodiments, the carbon fiber has an average diameter of no more than 20 μm, no more than 15 μm, no more than 13 μm or no more than 12 μm. In some embodiments, the carbon fiber has an average diameter of from 1 μm to 20 μm, from 5 μm to 15 μm, from 7 μm to 13 μm or from 8 μm to 12 μm.
In some embodiments, the length of the carbon fiber is significantly larger than its diameter. In some embodiments, the carbon fiber has an aspect ratio, defined as the average ratio of the length (“L”) and the largest diameter (“D”) (L/D) of at least 5, at least 10, at least 15, at least 20, or at least 25, or at least 30 or at least 50.
The polymer composition may also comprise one or more additives commonly used in the art including plasticizers, colorants, pigments, (e.g. black pigments such as carbon black and nigrosine), antistatic agents, dyes, lubricants (e.g. linear low density polyethylene, calcium or magnesium stearate or sodium montanate), thermal stabilizers, light stabilizers, flame retardants, nucleating agents and antioxidants. As used herein, additives exclude the thermally conductive fillers and the electrically conductive carbon fibers.
In embodiments including additives, the total additive concentration is less than 5 wt. %, or less than 4 wt. %, or less than 3 wt. %, or less than 2 wt. %, or less than 1 wt. %.
The present polymer composition comprises a thermoplastic polymer, a thermally conductive filler and an electrically conductive carbon fiber. Also, as previously mentioned, the polymer composition is substantially free of glass fiber.
In some embodiments, the weight ratio of the total weight of the electrically conductive carbon fiber(s) to the total weight of all non-thermoplastic polymer components in the polymer composition is no more than 1:3.8, or no more than 1:3.7, or no more than 1:3.6, or no more than 1:3.5 or no more than 1:3.4, or no more than 1:3.3, or no more than 1:3.2, or no more than 1:3.1, or no more than 1:3.0.
In some embodiments, the ratio of the total weight of the electrically conductive carbon fiber(s) to the total weight of all non-thermoplastic polymer components in the polymer composition is at least 1:1, or at least 1:1.1, or at least 1:1.2, or at least 1:1.3, or at least 1:1.4, or at least 1:1.5, or at least 1:1.6, or at least 1:1.7, or at least 1:1.8.
In some embodiments, the ratio of the total weight of electrically conductive carbon fiber(s) to the total weight of all non-thermoplastic polymer components in the polymer composition is from 1:1.0 to 1:3.8, or from 1:1.1 to 1:3.7, or from 1:1.2 to 1:3.6, or from 1:1.3 to 1:3.5, or from 1:1.4 to 1:3.4, or from 1:1.5 to 1:3.3, or from 1:1.6 to 1:3.2 or from 1:1.7 to 1:3.1 or from 1:1.8 to 1:3.0.
As mentioned above, the use of the electrically conductive carbon fiber allows the thermal conductivity properties of the polymer composition to be improved without encountering the limitations inherent in trying to achieve such improvement using only purely thermally conductive fillers. In some embodiments, the polymer composition exhibits in-plane thermal conductivity of at least 7 W/(m·K), or at least 8 W/(m·K), or at least 9 W/(m·K), or at least 10 W/(m·K), or at least 11 W/(m·K), or at least 12 W/(m·K), or at least 13 W/(m·K). Stated another way, the polymer composition exhibits a thermal conductivity of at least 1.5 times, or at least 2 times, or least 2.5 times, or at least 3 times, than the thermal conductivity of an analogous polymer composition in which the electrically conductive carbon fibers are replaced with glass fibers. In-plane thermal conductivity can be measured by the flash method according to ASTM E1461-13, “Standard Test Method for Thermal Diffusivity by the Flash Method”.
The thermal conductivity improvements do not come at the expense of the electrical resistivity of the polymer composition. Instead, the resistivity of the present polymer composition is surprisingly and unexpectedly substantially maintained as compared to the analogous polymer composition in which the electrically conductive carbon fibers are replaced with glass fibers. In some embodiments, the polymer composition has a volume resistivity of at least 109 Ω·cm, or at least 1010 Ω·cm, or at least 1011 Ω·cm, or at least 1012 Ω·cm, or at least 1013 Ω·cm, or at least 1014 Ω·cm, or at least 1015 Ω·cm, or at least 1016 Ω·cm. In some embodiments, the polymer composition has a volume resistivity of no more than 1018 Ω·cm. In some embodiments, the polymer composition has a volume resistivity of from 109 Ω·cm to 1018 Ω·cm, from 1010 Ω·cm to 1018 Ω·cm, from 1011 Ω·cm to 1018 Ω·cm, from 1012 Ω·cm to 1018 Ω·cm, from 1013 Ω·cm to 1018 Ω·cm, from 1014 Ω·cm to 1018 Ω·cm, from 1015 Ω·cm to 1018 Ω·cm, or from 1016 Ω·cm to 1018 Ω·cm. Volume resistivity can be measured according to ASTM D257.
Further surprising is the fact that the tensile and flexural moduli of the polymer compositions comprising carbon fibers are increased relative to analogous polymer compositions in which the electrically conductive carbon fibers are replaced with glass fibers. In some embodiments, the polymer composition has a flexural modulus of at least 25 GPa, at least 30 GPa or at least 35 GPa. In some embodiments, the polymer composition has a flexural modulus of no more than 55 GPa, no more than 50 GPa or no more than 45 GPa. In some embodiments, the polymer composition has a flexural modulus of from 25 GPa to 55 Gpa, from 30 GPa to 50 GPa or from 35 GPa to 45 GPa. In some embodiments, the polymer composition has a tensile modulus of at least 25 GPa, at least 30 GPa or at least 35 GPa. In some embodiments, the polymer composition has a tensile modulus of no more than 55 GPa, no more than 50 GPa or no more than 45 GPa. In some embodiments, the polymer composition has a tensile modulus of from 25 GPa to 55 Gpa, from 30 GPa to 50 GPa or from 35 GPa to 45 GPa.
In some embodiments, the polymer composition has only a single thermoplastic polymer and/or a single thermally conductive filler. In some such embodiments, the thermoplastic polymer is either polyphenyl sulfide or polyphthalamide, and/or the thermally conductive filler is boron nitride.
Methods of making the polymer composition are also provided.
The polymer composition can be made by methods well known to the person of skill in the art. For example, such methods include, but are not limited to, melt-mixing processes. Melt-mixing processes are typically carried out by heating the polymer components above the glass transition or melting temperature of the thermoplastic polymers. Suitable melt-mixing apparatus are, for example, kneaders, Banbury mixers, single-screw extruders, and twin-screw extruders. Preferably, use is made of an extruder fitted with means for dosing all the desired components to the extruder, either to the extruder's throat or to the barrel. The components may be fed simultaneously, i.e., as a dry blend of one or more powders granules, or may be fed separately.
The order of combination the components during melt-mixing is not particularly limited. In one embodiment, the component can be mixed in a single batch, such that the desired amounts of each component are added together and subsequently mixed. In other embodiments, a first sub-set of components can be initially mixed together and one or more of the remaining components can be added to the mixture for further mixing. For clarity, the total desired amount of each component does not have to be mixed as a single quantity. For example, for one or more of the components, a partial quantity can be initially added and mixed and, subsequently, some or all of the remainder can be added and mixed.
Filaments and shaped articles comprising the present polymer composition as well as methods of making the filaments and shaped articles are also provided.
The polymer composition are well suited for the manufacture of articles useful in a wide variety of applications. For example, the present polymer compositions may be especially suitable for use as a functional or structural part of i) an electronic device, ii) an automobile, iii) a motor, iv) a battery, v) an LED, vi) an electronic boards, vii) an electronic vehicle charging station, viii) a vacuum or vacuum system, etc.
Shaped articles may be made from the polymer composition using any suitable melt-processing method such as injection molding, extrusion molding, roto-molding, compression molding or blow-molding.
Shaped articles may also be made by additive manufacturing, where the shaped article is printed from the polymer composition.
Additive manufacturing systems are used to print or otherwise build a shaped object from a digital representation of the shaped object by one or more additive manufacturing techniques. Examples of commercially available additive manufacturing techniques include extrusion-based techniques, selective laser sintering, powder/binder jetting, electron-beam melting, and stereolithography processes. For each of these techniques, the digital representation of the shaped object is initially sliced into multiple horizontal layers. For each layer, a tool path is then generated, which provides instructions for the particular additive manufacturing system to print the given layer.
For example, in an extrusion-based additive manufacturing system, a shaped article may be printed from a digital representation of the shaped article in a layer-by-layer manner by extruding and adjoining strips of the polymer composition. The polymer composition is extruded through an extrusion tip carried by a print head of the system, and is deposited as a sequence of roads on a platen in an x-y plane. The extruded material fuses to previously deposited material and solidifies as it cools. The position of the print head relative to the substrate is then incremented along a z-axis (perpendicular to the x-y plane), and the process is repeated to form a shaped article resembling the digital representation. An example of an extrusion-based additive manufacturing system is Fused Filament Fabrication (“FFF”).
As another example, in a powder-based additive manufacturing system, a laser is used to locally sinter powder into a solid part. A shaped article is created by sequentially depositing a layer of powder followed by a laser pattern to sinter an image onto that layer. An example of a powder-based additive manufacturing system is Selective Laser Sintering (“SLS”).
As another example, shaped articles can be prepared using a continuous Fiber-Reinforced Thermoplastic (FRTP) printing method. This method is based on fused-deposition modeling and prints a combination of fibers and resins.
Accordingly, some embodiments include a method of making a shaped article comprising printing layers of the polymer composition to form the shaped article by an extrusion-based additive manufacturing system (for example FFF), a powder-based additive manufacturing system (for example SLS), or a continuous FRTP printing method.
Some embodiments include a filament including the polymer composition. Preferably, the filament is suitable for use in additive manufacturing methods as described above, such as FFF.
Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.
Exemplary embodiments will now be described in the following non-limiting examples.
The resistivity, thermal conductivity and mechanical properties were evaluated for various embodiments.
RYTON® PPS from Solvay Specialty Polymers USA, LLC.
Boron nitride, from Momentive Performance Materials Inc.
Zinc oxide (ZnO)) from DreyTek, Inc.
Magnesium oxide (MgO)) from Ube Material Industries, Ltd.
Glass Fibers from 3B—the fiberglass company.
Carbon Fibers from Solvay Cytec.
Mold release agent, HDPE 6007G from Nexeo Plastics.
Each formulation was melt compounded using a 26 mm diameter Coperion® ZSK-26 co-rotating partially intermeshing twin screw extruder having an L/D ratio of 48:1. The barrel sections 2 through 12 and the die were heated to set point temperatures as follows: Barrels 2-6: 300° C.; Barrels 7-12: 300° C.; Die: 300° C.
In each case, the thermoplastic polymer(s) was/were fed at barrel section 1 using a gravimetric feeder at throughput rates in the range 30-35 lb/hr. The extruder was operated at screw speeds of around 200 RPM. Vacuum was applied at barrel zone 10 with a vacuum level of about 27 inches of mercury. A single-hole die was used for all the polymer compositions to give a filament approximately 2.6 to 2.7 mm in diameter and the polymer filament exiting the die was cooled in water and fed to the pelletizer to generate pellets approximately 2.7 mm in length. Pellets were dried prior being injection molded into a sample in accordance with the test procedure to be applied to the sample.
Volume resistivity was measured according to ASTM D257.
The following ISO test methods were employed in evaluating the mechanical properties of the formulations:
Samples were prepared in accordance with the ISO procedure.
In- and through plane thermal conductivity were measured by the flash method according to ASTM E1461-13, “Standard Test Method for Thermal Diffusivity by the Flash Method.”
Table 1 shows the formulations prepared and data obtained relative thereto. Surprisingly and unexpectedly, and as also shown in
Further, and as shown in Table 1 and
This application claims priority to US Provisional Application filed on 26 Jul. 2021 with No. 63/225,627, the whole content of this application being incorporated herein by reference for all purposes.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/069494 | 7/12/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63225627 | Jul 2021 | US |
