Patent Application
20230303839
Electric vehicles, such as battery-electric vehicles, plug-in hybrid-electric vehicles, mild hybrid-electric vehicles, or full hybrid-electric vehicles generally have an electric powertrain that contains an electric propulsion source (e.g., battery) and a transmission. High performance polymeric materials are often employed in the electric vehicle for various components, such as in high voltage connectors, power converter housings, battery assembly housings, fluid pumps, inverters, busbars, twisted cables, individual sense lead wires, wire crimps, grommet moldings, quick connectors, tees, interconnects, guide rails, sealing rings (e.g., brushless direct current sealing rings, battery cell sealing rings, etc.), etc. Many of these components are “insert molded” in that they are formed by inserting a member (e.g., metal) into a polymer composition as it is being molded. While this process enables the formation of complex parts, the stark differences in the coefficients of thermal expansion of the different materials can lead to cracking when the part is exposed to changes in temperature. For this reason, various attempts have been made to develop performance polymer compositions with a high degree of thermal shock resistance. Unfortunately, none of the attempts have been able to achieve a sufficiently high degree of thermal shock resistance to allow their use in many EV product applications. Furthermore, to the extent higher thermal shock resistance values can be achieved at all, it is often with a commensurate reduction in the insulative, mechanical, and/or flow properties of the resulting composition.
As such, a need currently exists for polymer compositions that can exhibit a high degree of thermal shock resistance in combination with other beneficial properties for use in electric vehicle components.
In accordance with one embodiment of the present invention, a polymer composition is disclosed that comprises an impact modifier and a fibrous filler dispersed within a polymer matrix. The polymer matrix contains a high performance thermoplastic polymer that exhibits a deflection temperature under load of about 40° C. or more as determined in accordance with ISO 75-2:2013 at a load of 1.8 MPa and a melting temperature of about 140° C. or more. The polymer composition exhibits a thermal shock resistance value of about 800 or more.
Other features and aspects of the present invention are set forth in greater detail below.
A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:
Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.
It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention.
Generally speaking, the present invention is directed to a polymer composition that contains an impact modifier and fibrous filler dispersed within a polymer matrix. The polymer matrix likewise includes a high performance thermoplastic polymer having a deflection temperature under load of about 40° C. or more as determined in accordance with ISO 75-2:2013 at a load of 1.8 MPa and a melting temperature of about 140° C. or more. By selectively controlling the particular components of the composition and their relative concentration, it has been discovered that the resulting composition may exhibit an enhanced thermal shock resistance, which is useful in forming components of an electric vehicle, such as a battery-powered electric vehicle, fuel cell-powered electric vehicle, plug-in hybrid-electric vehicle (PHEV), mild hybrid-electric vehicle (MHEV), full hybrid-electric vehicle (FHEV), etc. More particularly, the polymer composition may exhibit a thermal shock resistance value of about 800 or more, in some embodiments about 1,000 or more, in some embodiments about 1,200 or more, in some embodiments about 1,500 or more, in some embodiments about 1,800 or more, in some embodiments about 2,000 or more, and in some embodiments, about 3,000 or more. As used herein, the “thermal shock resistance value” is determined according to the test described below and generally refers to the number of heating cycles a set of sample components is able to withstand without undergoing visual cracking. The high degree of thermal shock resistance may even be achieved at relatively small thickness values, such as about 4 millimeters or less, in some embodiments about from about 0.2 to about 3.2 millimeters or less, in some embodiments from about 0.4 to about 3.0 millimeters, and in some embodiments, from about 0.5 to about 2.8 millimeters (e.g., 1.2 or 2.5 mm).
In addition to exhibit a high degree of thermal shock resistance, the polymer composition may also exhibit good insulative properties, even at relatively small thickness values such as described above. The insulative properties of the polymer composition may be characterized by a high comparative tracking index (“CTI”), such as about 150 volts or more, in some embodiments about 200 volts or more, in some embodiments about 300 volts or more, in some embodiments 550 volts or more, in some embodiments about 580 volts or more, and in some embodiments, about 600 volts or more, as determined in accordance with IEC 60112:2003 at a part thickness such as noted above (e.g., 3 millimeters).
While exhibiting good thermal shock resistance and high CTI values, the composition may still exhibit good flow properties as reflected by a relatively low melt viscosity, such as about 30 kP or less, in some embodiments about 20 kP or less, in some embodiments about 10 kP or less, in some embodiments about 5 kP or less, and in some embodiments, from about 2 to about 50 kP, as determined in accordance with ISO 11443:2021 at a temperature of about 310° C. and at a shear rate of 400 s-1. Despite having a low melt viscosity, the polymer composition may nevertheless maintain a high degree of impact strength as well as tensile strength, which can provide enhanced flexibility for the resulting component. For example, the polymer composition may exhibit a notched Izod impact strength of about 5 kJ/m2 or more, such as in some embodiments from about 6 to about 50 kJ/m2, and in some embodiments, from about 7 to about 30 kJ/m2, as determined at a temperature of 23° C. in accordance with ISO 180:2019, as well as a Charpy notched impact strength of about 6 kJ/m2 or more, such as in some embodiments from about 8 to about 50 kJ/m2, and in some embodiments, from about 10 to about 30 kJ/m2, as determined at a temperature of 23° C. in accordance with ISO 179-1:2010. For example, the composition may exhibit a tensile stress at break of about 100 MPa or more, in some embodiments from about 100 MPa to about 200 MPa, in some embodiments from about 110 to about 180 MPa, and in some embodiments, from about 120 to about 170 MPa; a tensile break strain of about 1% or more, in some embodiments from about 1% to about 10%; and/or a tensile modulus of about 15,000 MPa or less, in some embodiments from about 1,000 MPa to about 12,000 MPa, in some embodiments from about 5,000 MPa to about 11,000 MPa. The tensile properties may be determined in accordance with ISO Test No. 527:2019 at a temperature of 23° C. The composition may also exhibit a flexural strength of about 50 MPa or more, in some embodiments from about 100 to about 350 MPa, and in some embodiments from about 150 to about 300 MPa, and/or a flexural modulus of from about 5,000 to about 20,000, in some embodiments from about 8,000 MPa to about 18,000 MPa, and in some embodiments, from about 10,000 MPa to about 16,000 MPa. The flexural properties may be determined in accordance with ISO 178:2019 at a temperature of 23° C.
Notably, the present inventors have also discovered that the polymer composition is not highly sensitive to aging at high temperatures. For example, a part formed from the composition may be aged in an atmosphere having a temperature of from about 100° C. or more, in some embodiments from about 150° C. to about 200° C., and in some embodiments, from about 200° C. to about 260° C. (e.g., 240° C.) for a time period of about 100 hours or more, in some embodiments from about 300 hours to about 3000 hours, and in some embodiments, from about 400 hours to about 2500 hours (e.g., about 1,000 hours). Even after aging, the mechanical properties (e.g., impact strength, tensile properties, and/or flexural properties) may remain within the ranges noted above. For example, the ratio of a particular mechanical property (e.g., Charpy unnotched impact strength, tensile modulus, tensile strength, tensile break strain, etc.) after “aging” at 240° C. for 1,000 hours to the initial mechanical property prior to such aging may be about 0.4 or more, in some embodiments about 0.5 or more, and in some embodiments, from about 0.6 to 1.0. In one embodiment, for example, a part may exhibit a Charpy notched impact strength after being aged at a high temperature (e.g., 240° C.) for 1,000 hours of greater than about 5 kJ/m2, in some embodiments from about 6 to about 30 kJ/m2, and in some embodiments, from about 7 to about 20 kJ/m2, measured according to ISO 179-1:2010 at a temperature of 23° C. After being aged at a high temperature atmosphere (e.g., 240° C.) for 1,000 hours, the part may also exhibit a tensile strength of from about 50 to about 300 MPa, in some embodiments from about 80 to about 200 MPa, and in some embodiments, from about 100 to about 150 MPa; a tensile modulus of from about 5,000 to about 25,000 MPa, in some embodiments from about 8,000 to about 22,000 MPa, and in some embodiments, from about 10,000 to about 20,000 MPa; and/or a tensile break strain of from about 0.4% to about 8%, in some embodiments from about 0.6% to about 5%, and in some embodiments, from about 0.8% to about 3%, as determined at a temperature of 23° C. in accordance with ISO 527-2/1A:2019.
The polymer composition can also exhibit good flame retardant characteristics. For instance, a polymer composition can meet the V-0 flammability standard at a thickness of 0.8 millimeters. The flame retarding efficacy may be determined according to the UL 94 Vertical Burn Test procedure of the “Test for Flammability of Plastic Materials for Parts in Devices and Appliances”, 5th Edition, Oct. 29, 1996. The ratings according to the UL 94 test are listed in the following table:
The “afterflame time” is an average value determined by dividing the total afterflame time (an aggregate value of all samples tested) by the number of samples. The total afterflame time is the sum of the time (in seconds) that all the samples remained ignited after two separate applications of a flame as described in the UL-94 VTM test. Shorter time periods indicate better flame resistance, i.e., the flame went out faster. For a V-0 rating, the total afterflame time for five (5) samples, each having two applications of flame, must not exceed 50 seconds. Using the flame retardant of the present invention, the polymer composition may achieve at least a V-1 rating, and typically a V-0 rating, for specimens having a thickness of 0.8 millimeters.
Various embodiments of the present invention will now be described in greater detail below.
As noted, the polymer matrix contains one or more high performance thermoplastic polymers. By “high performance”, it is generally mean that the polymers have a high degree of heat resistance, such as reflected by a deflection temperature under load (“DTUL”) of about 40° C. or more, in some embodiments about 50° C. or more, in some embodiments about 60° C. or more, in some embodiments from about from about 80° C. to about 250° C., and in some embodiments, from about 100° C. to about 200° C., as determined in accordance with ISO 75-2:2013 at a load of 1.8 MPa. The thermoplastic polymers may also be semi-crystalline or crystalline in nature and exhibit a high melting temperature, such as about 140° C. or more, in some embodiments from about 150° C. to about 400° C., and in some embodiments, from about 200° C. to about 380° C. The melting temperature may be determined using differential scanning calorimetry (“DSC”) in accordance with ISO 11357-3:2018. Of course, in addition to exhibiting a high degree of heat resistance and a high melting temperature, the thermoplastic polymers may also exhibit a high glass transition temperature, such as about 10° C. or more, in some embodiments about 20° C. or more, in some embodiments about 30° C. or more, in some embodiments about 40° C. or more, in some embodiments about 50° C. or more, and in some embodiments, from about 60° C. to about 320° C. The glass transition temperature may be determined using differential scanning calorimetry in accordance with ISO 11357-2:2020.
Suitable thermoplastic polymers for this purpose may include, for instance, polyolefins (e.g., ethylene polymers, propylene polymers, etc.), polyamides (e.g., aliphatic, semi-aromatic, or aromatic polyamides), polyesters, polyarylene sulfides, liquid crystalline polymers (e.g., wholly aromatic polyesters, polyesteramides, etc.), polyethers (e.g., polyoxymethylene), etc., as well as blends thereof. The exact choice of the polymer system will depend upon a variety of factors, such as the nature of other fillers included within the composition, the manner in which the composition is formed and/or processed, and the specific requirements of the intended application.
Aromatic polymers, for instance, are particularly suitable in some applications. One example of a suitable semi-crystalline aromatic polymer, for instance, is an aromatic polyester, which may be a condensation product of at least one diol (e.g., aliphatic and/or cycloaliphatic) with at least one aromatic dicarboxylic acid, such as those having from 4 to 20 carbon atoms, and in some embodiments, from 8 to 14 carbon atoms. Suitable diols may include, for instance, neopentyl glycol, cyclohexanedimethanol, 2,2-dimethyl-1,3-propane diol and aliphatic glycols of the formula HO(CH2)nOH where n is an integer of 2 to 10. Suitable aromatic dicarboxylic acids may include, for instance, isophthalic acid, terephthalic acid, 1,2-di(p-carboxyphenyl)ethane, 4,4′-dicarboxydiphenyl ether, etc., as well as combinations thereof. Fused rings can also be present such as in 1,4- or 1,5- or 2,6-naphthalene-dicarboxylic acids. Particular examples of such aromatic polyesters may include, for instance, poly(ethylene terephthalate) (PET), poly(1,4-butylene terephthalate) (PBT), poly(1,3-propylene terephthalate) (PPT), poly(1,4-butylene 2,6-naphthalate) (PBN), poly(ethylene 2,6-naphthalate) (PEN), poly(1,4-cyclohexylene dimethylene terephthalate) (PCT), as well as mixtures of the foregoing.
Derivatives and/or copolymers of aromatic polyesters (e.g., polyethylene terephthalate) may also be employed. For instance, in one embodiment, a modifying acid and/or diol may be used to form a derivative of such polymers. As used herein, the terms “modifying acid” and “modifying diol” are meant to define compounds that can form part of the acid and diol repeat units of a polyester, respectively, and which can modify a polyester to reduce its crystallinity. Examples of modifying acid components may include, but are not limited to, isophthalic acid, phthalic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, 2,6-naphthaline dicarboxylic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, suberic acid, 1,12-dodecanedioic acid, etc. In practice, it is often preferable to use a functional acid derivative thereof such as the dimethyl, diethyl, or dipropyl ester of the dicarboxylic acid. The anhydrides or acid halides of these acids also may be employed where practical. Examples of modifying diol components may include, but are not limited to, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,2-propanediol, 1,3-propanediol, 2-methy-1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 2,2,4,4-tetramethyl 1,3-cyclobutane diol, Z,8-bis(hydroxymethyltricyclo-[5.2.1.0]-decane wherein Z represents 3, 4, or 5; 1,4-bis(2-hydroxyethoxy)benzene, 4,4′-bis(2-hydroxyethoxy) diphenylether [bis-hydroxyethyl bisphenol A], 4,4′-Bis(2-hydroxyethoxy)diphenylsulfide [bis-hydroxyethyl bisphenol S] and diols containing one or more oxygen atoms in the chain, e.g. diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, etc. In general, these diols contain 2 to 18, and in some embodiments, 2 to 8 carbon atoms. Cycloaliphatic diols can be employed in their cis- or trans-configuration or as mixtures of both forms.
The aromatic polyesters, such as described above, typically have a DTUL value of from about 40° C. to about 80° C., in some embodiments from about 45° C. to about 75° C., and in some embodiments, from about 50° C. to about 70° C. as determined in accordance with ISO 75-2:2013 at a load of 1.8 MPa. The aromatic polyesters likewise typically have a glass transition temperature of from about 30° C. to about 120° C., in some embodiments from about 40° C. to about 110° C., and in some embodiments, from about 50° C. to about 100° C., as well as a melting temperature of from about 170° C. to about 300° C., in some embodiments from about 190° C. to about 280° C., and in some embodiments, from about 210° C. to about 260° C. The aromatic polyesters may also have an intrinsic viscosity of from about 0.1 dl/g to about 6 dl/g, in some embodiments from about 0.2 to about 5 dl/g, and in some embodiments from about 0.3 to about 1 dl/g, such as determined in accordance with ISO 1628-5:1998.
Polyarylene sulfides are also suitable semi-crystalline aromatic polymers. The polyarylene sulfide may be homopolymers or copolymers. For instance, selective combination of dihaloaromatic compounds can result in a polyarylene sulfide copolymer containing not less than two different units. For instance, when p-dichlorobenzene is used in combination with m-dichlorobenzene or 4,4′-dichlorodiphenylsulfone, a polyarylene sulfide copolymer can be formed containing segments having the structure of formula:
and segments having the structure of formula:
or segments having the structure of formula:
The polyarylene sulfide may be linear, semi-linear, branched or crosslinked. Linear polyarylene sulfides typically contain 80 mol% or more of the repeating unit -(Ar–S)-. Such linear polymers may also include a small amount of a branching unit or a cross-linking unit, but the amount of branching or cross-linking units is typically less than about 1 mol% of the total monomer units of the polyarylene sulfide. A linear polyarylene sulfide polymer may be a random copolymer or a block copolymer containing the above-mentioned repeating unit. Semi-linear polyarylene sulfides may likewise have a cross-linking structure or a branched structure introduced into the polymer a small amount of one or more monomers having three or more reactive functional groups. By way of example, monomer components used in forming a semi-linear polyarylene sulfide can include an amount of polyhaloaromatic compounds having two or more halogen substituents per molecule which can be utilized in preparing branched polymers. Such monomers can be represented by the formula R′Xn, where each X is selected from chlorine, bromine, and iodine, n is an integer of 3 to 6, and R′ is a polyvalent aromatic radical of valence n which can have up to about 4 methyl substituents, the total number of carbon atoms in R′ being within the range of 6 to about 16. Examples of some polyhaloaromatic compounds having more than two halogens substituted per molecule that can be employed in forming a semi-linear polyarylene sulfide include 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3-dichloro-5-bromobenzene, 1,2,4-triiodobenzene, 1,2,3,5-tetrabromobenzene, hexachlorobenzene, 1,3,5-trichloro-2,4,6-trimethylbenzene, 2,2′,4,4′-tetrachlorobiphenyl, 2,2′,5,5′-tetra-iodobiphenyl, 2,2′,6,6′-tetrabromo-3,3′,5,5′-tetramethylbiphenyl, 1,2,3,4-tetrachloronaphthalene, 1,2,4-tribromo-6-methylnaphthalene, etc., and mixtures thereof.
If desired, the polyarylene sulfide can be functionalized. For instance, a disulfide compound containing reactive functional groups (e.g., carboxyl, hydroxyl, amine, etc.) can be reacted with the polyarylene sulfide. Functionalization of the polyarylene sulfide can further provide sites for bonding between any optional impact modifiers and the polyarylene sulfide, which can improve distribution of the impact modifier throughout the polyarylene sulfide and prevent phase separation. The disulfide compound may undergo a chain scission reaction with the polyarylene sulfide during melt processing to lower its overall melt viscosity. When employed, disulfide compounds typically constitute from about 0.01 wt.% to about 3 wt.%, in some embodiments from about 0.02 wt.% to about 1 wt.%, and in some embodiments, from about 0.05 to about 0.5 wt.% of the polymer composition. The ratio of the amount of the polyarylene sulfide to the amount of the disulfide compound may likewise be from about 1000:1 to about 10:1, from about 500:1 to about 20:1, or from about 400:1 to about 30:1. Suitable disulfide compounds are typically those having the following formula:
wherein R3 and R4 may be the same or different and are hydrocarbon groups that independently include from 1 to about 20 carbons. For instance, R3 and R4 may be an alkyl, cycloalkyl, aryl, or heterocyclic group. In certain embodiments, R3 and R4 are generally nonreactive functionalities, such as phenyl, naphthyl, ethyl, methyl, propyl, etc. Examples of such compounds include diphenyl disulfide, naphthyl disulfide, dimethyl disulfide, diethyl disulfide, and dipropyl disulfide. R3 and R4 may also include reactive functionality at terminal end(s) of the disulfide compound. For example, at least one of R3 and R4 may include a terminal carboxyl group, hydroxyl group, a substituted or non-substituted amino group, a nitro group, or the like. Examples of compounds may include, without limitation, 2,2′-diaminodiphenyl disulfide, 3,3′-diaminodiphenyl disulfide, 4,4′-diaminodiphenyl disulfide, dibenzyl disulfide, dithiosalicyclic acid (or 2,2′-dithiobenzoic acid), dithioglycolic acid, α,α′-dithiodilactic acid, β,β′-dithiodilactic acid, 3,3′-dithiodipyridine, 4,4′dithiomorpholine, 2,2′-dithiobis(benzothiazole), 2,2′-dithiobis(benzimidazole), 2,2′-dithiobis(benzoxazole), 2-(4′-morpholinodithio)benzothiazole, etc., as well as mixtures thereof.
The melt flow rate of a polyarylene sulfide may be from about 100 to about 800 grams per 10 minutes (“g/10 min”), in some embodiments from about 200 to about 700 g/10 min, and in some embodiments, from about 300 to about 600 g/10 min, as determined in accordance with ISO 1133 at a load of 5 kg and temperature of 316° C.
The polyarylene sulfides, such as described above, typically have a DTUL value of from about 70° C. to about 220° C., in some embodiments from about 90° C. to about 200° C., and in some embodiments, from about 120° C. to about 180° C. as determined in accordance with ISO 75-2:2013 at a load of 1.8 MPa. The polyarylene sulfides likewise typically have a glass transition temperature of from about 50° C. to about 120° C., in some embodiments from about 60° C. to about 115° C., and in some embodiments, from about 70° C. to about 110° C., as well as a melting temperature of from about 220° C. to about 340° C., in some embodiments from about 240° C. to about 320° C., and in some embodiments, from about 260° C. to about 300° C.
In addition to the polymers referenced above, highly crystalline aromatic polymers may also be employed in the polymer composition. Particularly suitable examples of such polymers are liquid crystalline polymers, which have a high degree of crystallinity that enables them to effectively fill the small spaces of a mold. Liquid crystalline polymers are generally classified as “thermotropic” to the extent that they can possess a rod-like structure and exhibit a crystalline behavior in their molten state (e.g., thermotropic nematic state). Such polymers typically have a DTUL value of from about 120° C. to about 340° C., in some embodiments from about 140° C. to about 320° C., and in some embodiments, from about 150° C. to about 300° C., as determined in accordance with ISO 75-2:2013 at a load of 1.8 MPa. The polymers also have a relatively high melting temperature, such as from about 250° C. to about 400° C., in some embodiments from about 280° C. to about 390° C., and in some embodiments, from about 300° C. to about 380° C. Such polymers may be formed from one or more types of repeating units as is known in the art.
A liquid crystalline polymer may, for example, contain one or more aromatic ester repeating units, typically in an amount of from about 60 mol.% to 100 mol.%, in some embodiments from about 70 mol.% to about 99.5 mol.%, and in some embodiments, from about 80 mol.% to about 99 mol.% of the polymer. The aromatic ester repeating units may be generally represented by the following Formula (V):
wherein,
Typically, at least one of Y1 and Y2 are C(O). Examples of such aromatic ester repeating units may include, for instance, aromatic dicarboxylic repeating units (Y1 and Y2 in Formula V are C(O)), aromatic hydroxycarboxylic repeating units (Y1 is O and Y2 is C(O) in Formula V), as well as various combinations thereof.
Aromatic dicarboxylic repeating units, for instance, may be employed that are derived from aromatic dicarboxylic acids, such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl ether-4,4′-dicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4′-dicarboxybiphenyl, bis(4-carboxyphenyl)ether, bis(4-carboxyphenyl)butane, bis(4-carboxyphenyl)ethane, bis(3-carboxyphenyl)ether, bis(3-carboxyphenyl)ethane, etc., as well as alkyl, alkoxy, aryl and halogen substituents thereof, and combinations thereof. Particularly suitable aromatic dicarboxylic acids may include, for instance, terephthalic acid (“TA”), isophthalic acid (“IA”), and 2,6-naphthalenedicarboxylic acid (“NDA”). When employed, repeating units derived from aromatic dicarboxylic acids (e.g., IA, TA, and/or NDA) typically constitute from about 5 mol.% to about 60 mol.%, in some embodiments from about 10 mol.% to about 50 mol.%, and in some embodiments, from about 20 mol.% to about 40% of the polymer.
Aromatic hydroxycarboxylic repeating units may also be employed that are derived from aromatic hydroxycarboxylic acids, such as, 4-hydroxybenzoic acid; 4-hydroxy-4′-biphenylcarboxylic acid; 2-hydroxy-6-naphthoic acid; 2-hydroxy-5-naphthoic acid; 3-hydroxy-2-naphthoic acid; 2-hydroxy-3-naphthoic acid; 4′-hydroxyphenyl-4-benzoic acid; 3′-hydroxyphenyl-4-benzoic acid; 4′-hydroxyphenyl-3-benzoic acid, etc., as well as alkyl, alkoxy, aryl and halogen substituents thereof, and combination thereof. Particularly suitable aromatic hydroxycarboxylic acids are 4-hydroxybenzoic acid (“HBA”) and 6-hydroxy-2-naphthoic acid (“HNA”). When employed, repeating units derived from hydroxycarboxylic acids (e.g., HBA and/or HNA) typically constitute from about 10 mol.% to about 75 mol.%, in some embodiments from about 20 mol.% to about 60 mol.%, and in some embodiments, from about 30 mol.% to about 50% of the polymer.
Other repeating units may also be employed in the polymer. In certain embodiments, for instance, repeating units may be employed that are derived from aromatic diols, such as hydroquinone, resorcinol, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 4,4′-dihydroxybiphenyl (or 4,4′-biphenol), 3,3′-dihydroxybiphenyl, 3,4′-dihydroxybiphenyl, 4,4′-dihydroxybiphenyl ether, bis(4-hydroxyphenyl)ethane, etc., as well as alkyl, alkoxy, aryl and halogen substituents thereof, and combinations thereof. Particularly suitable aromatic diols may include, for instance, hydroquinone (“HQ”) and 4,4′-biphenol (“BP”). When employed, repeating units derived from aromatic diols (e.g., HQ and/or BP) typically constitute from about 1 mol.% to about 50 mol.%, in some embodiments from about 5 mol.% to about 45 mol.%, and in some embodiments, from about 10 mol.% to about 40% of the polymer. Repeating units may also be employed, such as those derived from aromatic amides (e.g., acetaminophen (“APAP”)) and/or aromatic amines (e.g., 4-aminophenol (“AP”), 3-aminophenol, 1,4-phenylenediamine, 1,3-phenylenediamine, etc.). When employed, repeating units derived from aromatic amides (e.g., APAP) and/or aromatic amines (e.g., AP) typically constitute from about 0.1 mol.% to about 20 mol.%, in some embodiments from about 0.5 mol.% to about 15 mol.%, and in some embodiments, from about 1 mol.% to about 10% of the polymer. It should also be understood that various other monomeric repeating units may be incorporated into the polymer. For instance, in certain embodiments, the polymer may contain one or more repeating units derived from non-aromatic monomers, such as aliphatic or cycloaliphatic hydroxycarboxylic acids, dicarboxylic acids, diols, amides, amines, etc. Of course, in other embodiments, the polymer may be “wholly aromatic” in that it lacks repeating units derived from non-aromatic (e.g., aliphatic or cycloaliphatic) monomers.
In one particular embodiment, the liquid crystalline polymer may be a “high naphthenic” polymer to the extent that it contains a relatively high content of repeating units derived from naphthenic hydroxycarboxylic acids and naphthenic dicarboxylic acids, such as NDA, HNA, or combinations thereof. That is, the total amount of repeating units derived from naphthenic hydroxycarboxylic and/or dicarboxylic acids (e.g., NDA, HNA, or a combination of HNA and NDA) is typically about 10 mol.% or more, in some embodiments about 12 mol.% or more, in some embodiments about 15 mol.% or more, and in some embodiments, from about 18 mol.% to about 35 mol.% of the polymer. In one embodiment, for instance, the repeating units derived from NDA may constitute 10 mol.% or more, in some embodiments about 12 mol.% or more, in some embodiments about 15 mol.% or more, and in some embodiments, from about 18 mol.% to about 35 mol.% of the polymer. When employed, the molar ratio of repeating units derived from HBA to the repeating units derived from naphthenic units (e.g., NDA, HNA, or both) may be selectively controlled within a specific range to help achieve the desired properties, such as from about 1 to about 20, in some embodiments from about 1.5 to about 15, and in some embodiments, from about 2 to about 10. The polymer may also contain repeating units derived from aromatic dicarboxylic acid(s) (e.g., IA and/or TA) in an amount of from about 1 mol.% to about 20 mol.%, and in some embodiments, from about 2 mol.% to about 15 mol.%; and/or aromatic diol(s) (e.g., BP and/or HQ) in an amount of from about 20 mol.% to about 50 mol.%, and in some embodiments, from about 30 mol.% to about 45 mol.%. In some cases, however, it may be desired to minimize the presence of such monomers in the polymer to help achieve the desired properties. For example, the total amount of repeating units derived from aromatic dicarboxylic acid(s) (e.g., IA and/or TA) and/or aromatic diols (e.g., BP and/or HQ) may be about 5 mol% or less, in some embodiments about 4 mol.% or less, and in some embodiments, from about 0.1 mol.% to about 3 mol.%, of the polymer.
In certain embodiments, all of the liquid crystalline polymers are “high naphthenic” polymers such as described above. In other embodiments, however, “low naphthenic” liquid crystalline polymers may also be employed in the composition in which the total amount of repeating units derived from naphthenic hydroxycarboxylic and/or dicarboxylic acids (e.g., NDA, HNA, or a combination of HNA and NDA) is less than 10 mol.%, in some embodiments about 8 mol.% or less, in some embodiments about 6 mol.% or less, and in some embodiments, from about 1 mol.% to about 5 mol.% of the polymer. When employed, it is generally desired that such low naphthenic polymers are present in only a relatively low amount. For example, when employed, low naphthenic liquid crystalline polymers typically constitute from about 1 wt.% to about 50 wt.%, in some embodiments from about 10 wt.% to about 45 wt.%, and in some embodiments, from about 15 wt.% to about 40 wt.% of the total amount of liquid crystalline polymers in the composition, and from about 0.5 wt.% to about 45 wt.%, in some embodiments from about 2 wt.% to about 35 wt.%, and in some embodiments, from about 5 wt.% to about 25 wt.% of the entire composition. Conversely, high naphthenic liquid crystalline polymers typically constitute from about 50 wt.% to about 99 wt.%, in some embodiments from about 55 wt.% to about 95 wt.%, and in some embodiments, from about 60 wt.% to about 85 wt.% of the total amount of liquid crystalline polymers in the composition, and from about 25 wt.% to about 65 wt.%, in some embodiments from about 30 wt.% to about 60 wt.%, and in some embodiments, from about 35 wt.% to about 55 wt.% of the entire composition.
Of course, besides aromatic polymers, aliphatic polymers may also be suitable for use as high performance, thermoplastic polymers in the polymer matrix. In one embodiment, for instance, polyamides may be employed that generally have a CO-NH linkage in the main chain and are obtained by condensation of an aliphatic diamine and an aliphatic dicarboxylic acid, by ring opening polymerization of lactam, or self-condensation of an amino carboxylic acid. For example, the polyamide may contain aliphatic repeating units derived from an aliphatic diamine, which typically has from 4 to 14 carbon atoms. Examples of such diamines include linear aliphatic alkylenediamines, such as 1,4-tetramethylenediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, etc.; branched aliphatic alkylenediamines, such as 2-methyl-1,5-pentanediamine, 3-methyl-1,5 pentanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine, etc.; as well as combinations thereof. Aliphatic dicarboxylic acids may include, for instance, adipic acid, sebacic acid, etc. Particular examples of such aliphatic polyamides include, for instance, nylon-4 (poly-a-pyrrolidone), nylon-6 (polycaproamide), nylon-11 (polyundecanamide), nylon-12 (polydodecanamide), nylon-46 (polytetramethylene adipamide), nylon-66 (polyhexamethylene adipamide), nylon-610, and nylon-612. Nylon-6 and nylon-66 are particularly suitable.
It should be understood that it is also possible to include aromatic monomer units in the polyamide such that it is considered aromatic (contains only aromatic monomer units are both aliphatic and aromatic monomer units). Examples of aromatic dicarboxylic acids may include, for instance, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxy-diacetic acid, 1,3-phenylenedioxy-diacetic acid, diphenic acid, 4,4′-oxydibenzoic acid, diphenylmethane-4,4′-dicarboxylic acid, diphenylsulfone-4,4′-dicarboxylic acid, 4,4′-biphenyldicarboxylic acid, etc. Particularly suitable aromatic polyamides may include poly(nonamethylene terephthalamide) (PA9T), poly(nonamethylene terephthalamide/nonamethylene decanediamide) (PA9T/910), poly(nonamethylene terephthalamide/nonamethylene dodecanediamide) (PA9T/912), poly(nonamethylene terephthalamide/11-aminoundecanamide) (PA9T/11), poly(nonamethylene terephthalamide/12-aminododecanamide) (PA9T/12), poly(decamethylene terephthalamide/11-aminoundecanamide) (PA10T/11), poly(decamethylene terephthalamide/12-aminododecanamide) (PA10T/12), poly(decamethylene terephthalamide/decamethylene decanediamide) (PA10T/1010), poly(decamethylene terephthalamide/decamethylene dodecanediamide) (PA10T/1012), poly(decamethylene terephlhalamide/tetramethylene hexanediamide) (PA10T/46), poly(decamethylene terephthalamide/caprolactam) (PA10T/6), poly(decamethylene terephthalamide/hexamethylene hexanediamide) (PA10T/66), poly(dodecamethylene lerephthalamide/dodecamelhylene dodecanediarnide) (PA12T/1212), poly(dodecamethylene terephthalamide/caprolactam) (PA12T/6), poly(dodecamethylene terephthalamide/hexamethylene hexanediamide) (PA12T/66), and so forth.
Suitable polyamides for the polymer matrix are typically crystalline or semi-crystalline in nature and thus has a measurable melting temperature. The melting temperature may be relatively high such that the composition can provide a substantial degree of heat resistance to a resulting part. For example, the polyamide may have a melting temperature of about 220° C. or more, in some embodiments from about 240° C. to about 325° C., and in some embodiments, from about 250° C. to about 335° C. The polyamide may also have a relatively high glass transition temperature, such as about 30° C. or more, in some embodiments about 40° C. or more, and in some embodiments, from about 45° C. to about 140° C.
Propylene polymers may also be suitable aliphatic high performance polymers for use in the polymer matrix. Any of a variety of propylene polymers or combinations of propylene polymers may generally be employed in the polymer matrix, such as propylene homopolymers (e.g., syndiotactic, atactic, isotactic, etc.), propylene copolymers, and so forth. In one embodiment, for instance, a propylene polymer may be employed that is an isotactic or syndiotactic homopolymer. The term “syndiotactic” generally refers to a tacticity in which a substantial portion, if not all, of the methyl groups alternate on opposite sides along the polymer chain. On the other hand, the term “isotactic” generally refers to a tacticity in which a substantial portion, if not all, of the methyl groups are on the same side along the polymer chain. In yet other embodiments, a copolymer of propylene with an α-olefin monomer may be employed. Specific examples of suitable α-olefin monomers may include ethylene, 1-butene; 3-methyl-1-butene; 3,3-dimethyl-1-butene; 1-pentene; 1-pentene with one or more methyl, ethyl or propyl substituents; 1-hexene with one or more methyl, ethyl or propyl substituents; 1-heptene with one or more methyl, ethyl or propyl substituents; 1-octene with one or more methyl, ethyl or propyl substituents; 1-nonene with one or more methyl, ethyl or propyl substituents; ethyl, methyl or dimethyl-substituted 1-decene; 1-dodecene; and styrene. The propylene content of such copolymers may be from about 60 mol.% to about 99 mol.%, in some embodiments from about 80 mol.% to about 98.5 mol.%, and in some embodiments, from about 87 mol.% to about 97.5 mol.%. The α-olefin content may likewise range from about 1 mol.% to about 40 mol.%, in some embodiments from about 1.5 mol.% to about 15 mol.%, and in some embodiments, from about 2.5 mol.% to about 13 mol.%.
Suitable propylene polymers are typically those having a DTUL value of from about 80° C. to about 250° C., in some embodiments from about 100° C. to about 220° C., and in some embodiments, from about 110° C. to about 200° C., as determined in accordance with ISO 75-2:2013 at a load of 1.8 MPa. The glass transition temperature of such polymers may likewise be from about 10° C. to about 80° C., in some embodiments from about 15° C. to about 70° C., and in some embodiments, from about 20° C. to about 60° C. Further, the melting temperature of such polymers may be from about 50° C. to about 250° C., in some embodiments from about 90° C. to about 220° C., and in some embodiments, from about 100° C. to about 200° C.
Oxymethylene polymers may also be suitable aliphatic high performance polymers for use in the polymer matrix. Oxymethylene polymers can be either one or more homopolymers, copolymers, or a mixture thereof. Homopolymers are prepared by polymerizing formaldehyde or formaldehyde equivalents, such as cyclic oligomers of formaldehyde. Copolymers can contain one or more comonomers generally used in preparing polyoxymethylene compositions. Commonly used comonomers include alkylene oxides of 2-12 carbon atoms. If a copolymer is selected, the quantity of comonomer will typically not be more than 20 weight percent, in some embodiments not more than 15 weight percent, and, in some embodiments, about two weight percent. Comonomers can include ethylene oxide and butylene oxide. It is preferred that the homo- and copolymers are: 1) those whose terminal hydroxy groups are end-capped by a chemical reaction to form ester or ether groups; or, 2) copolymers that are not completely end-capped, but that have some free hydroxy ends from the comonomer unit. Typical end groups, in either case, are acetate and methoxy.
As indicated above, an impact modifier is also employed within the polymer composition. Typically, the impact modifier(s) constitute from about 1 to about 20 parts, in some embodiments from about 2 to about 15 parts, and in some embodiments, from about 5 to about 10 parts by weight per 100 parts by weight of the polyarylene sulfide(s). For example, the impact modifiers may constitute from about 0.1 wt.% to about 20 wt.%, in some embodiments from about 0.5 wt.% to about 15 wt.%, and in some embodiments, from about 1 wt.% to about 10 wt.% of the polymer composition.
Examples of suitable impact modifiers may include, for instance, polyepoxides, polyurethanes, polybutadiene, acrylonitrile-butadiene-styrene, polyamides, block copolymers (e.g., polyether-polyamide block copolymers), etc., as well as mixtures thereof. In one embodiment, an olefin copolymer is employed that is “epoxy-functionalized” in that it contains, on average, two or more epoxy functional groups per molecule. The copolymer generally contains an olefinic monomeric unit that is derived from one or more α-olefins. Examples of such monomers include, for instance, linear and/or branched α-olefins having from 2 to 20 carbon atoms and typically from 2 to 8 carbon atoms. Specific examples include ethylene, propylene, 1-butene; 3-methyl-1-butene; 3,3-dimethyl-1-butene; 1-pentene; 1-pentene with one or more methyl, ethyl or propyl substituents; 1-hexene with one or more methyl, ethyl or propyl substituents; 1-heptene with one or more methyl, ethyl or propyl substituents; 1-octene with one or more methyl, ethyl or propyl substituents; 1-nonene with one or more methyl, ethyl or propyl substituents; ethyl, methyl or dimethyl-substituted 1-decene; 1-dodecene; and styrene. Particularly desired α-olefin monomers are ethylene and propylene. The copolymer may also contain an epoxy-functional monomeric unit. One example of such a unit is an epoxy-functional (meth)acrylic monomeric component. As used herein, the term “(meth)acrylic” includes acrylic and methacrylic monomers, as well as salts or esters thereof, such as acrylate and methacrylate monomers. For example, suitable epoxy-functional (meth)acrylic monomers may include, but are not limited to, those containing 1,2-epoxy groups, such as glycidyl acrylate and glycidyl methacrylate. Other suitable epoxy-functional monomers include allyl glycidyl ether, glycidyl ethacrylate, and glycidyl itoconate. Other suitable monomers may also be employed to help achieve the desired molecular weight.
Of course, the copolymer may also contain other monomeric units as is known in the art. For example, another suitable monomer may include a (meth)acrylic monomer that is not epoxy-functional. Examples of such (meth)acrylic monomers may include methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, s-butyl acrylate, i-butyl acrylate, t-butyl acrylate, n-amyl acrylate, i-amyl acrylate, isobornyl acrylate, n-hexyl acrylate, 2-ethylbutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate, methylcyclohexyl acrylate, cyclopentyl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, 2-hydroxyethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, i-propyl methacrylate, i-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, i-amyl methacrylate, s-butyl-methacrylate, t-butyl methacrylate, 2-ethylbutyl methacrylate, methylcyclohexyl methacrylate, cinnamyl methacrylate, crotyl methacrylate, cyclohexyl methacrylate, cyclopentyl methacrylate, 2-ethoxyethyl methacrylate, isobornyl methacrylate, etc., as well as combinations thereof. In one particular embodiment, for example, the copolymer may be a terpolymer formed from an epoxy-functional (meth)acrylic monomeric component, α-olefin monomeric component, and non-epoxy functional (meth)acrylic monomeric component. The copolymer may, for instance, be poly(ethylene-co-butylacrylate-co-glycidyl methacrylate), which has the following structure:
wherein, x, y, and z are 1 or greater.
The relative portion of the monomeric component(s) may be selected to achieve a balance between epoxy-reactivity and melt flow rate. More particularly, high epoxy monomer contents can result in good reactivity with the polyarylene sulfide, but too high of a content may reduce the melt flow rate to such an extent that the copolymer adversely impacts the melt strength of the polymer blend. Thus, in most embodiments, the epoxy-functional (meth)acrylic monomer(s) constitute from about 1 wt.% to about 20 wt.%, in some embodiments from about 2 wt.% to about 15 wt.%, and in some embodiments, from about 3 wt.% to about 10 wt.% of the copolymer. The α-olefin monomer(s) may likewise constitute from about 55 wt.% to about 95 wt.%, in some embodiments from about 60 wt.% to about 90 wt.%, and in some embodiments, from about 65 wt.% to about 85 wt.% of the copolymer. When employed, other monomeric components (e.g., non-epoxy functional (meth)acrylic monomers) may constitute from about 5 wt.% to about 35 wt.%, in some embodiments from about 8 wt.% to about 30 wt.%, and in some embodiments, from about 10 wt.% to about 25 wt.% of the copolymer. The resulting melt flow rate is typically from about 1 to about 30 grams per 10 minutes (“g/10 min”), in some embodiments from about 2 to about 20 g/10 min, and in some embodiments, from about 3 to about 15 g/10 min, as determined in accordance with ASTM D1238-13 at a load of 2.16 kg and temperature of 190° C.
If desired, additional impact modifiers may also be employed in combination with the epoxy-functional impact modifier. For example, the additional impact modifier may include a block copolymer in which at least one phase is made of a material that is hard at room temperature but fluid upon heating and another phase is a softer material that is rubber-like at room temperature. For instance, the block copolymer may have an A-B or A-B-A block copolymer repeating structure, where A represents hard segments and B is a soft segment. Non-limiting examples of impact modifiers having an A-B repeating structure include polyamide/polyether, polysulfone/polydimethylsiloxane, polyurethane/polyester, polyurethane/polyether, polyester/polyether, polycarbonate/polydimethylsiloxane, and polycarbonate/polyether. Triblock copolymers may likewise contain polystyrene as the hard segment and either polybutadiene, polyisoprene, or polyethylene-co-butylene as the soft segment. Similarly, styrene butadiene repeating co-polymers may be employed, as well as polystyrene/polyisoprene repeating polymers. In one particular embodiment, the block copolymer may have alternating blocks of polyamide and polyether. Such materials are commercially available, for example from Atofina under the PEBAX™ trade name. The polyamide blocks may be derived from a copolymer of a diacid component and a diamine component or may be prepared by homopolymerization of a cyclic lactam. The polyether block may be derived from homo- or copolymers of cyclic ethers such as ethylene oxide, propylene oxide, and tetrahydrofuran.
A fibrous filler is also employed in a polymer composition. Such fibrous fillers typically constitute from about 10 to about 80 parts, in some embodiments from about 20 to about 75 parts, and in some embodiments, from about 25 to about 60 parts by weight per 100 parts by weight of the polyarylene sulfide(s). For example, fibrous fillers may constitute from about 10 wt.% to about 60 wt.%, in some embodiments from about 15 wt.% to about 50 wt.%, and in some embodiments, from about 20 wt.% to about 45 wt.% of the polymer composition.
Any of a variety of different types of fibers may generally be employed, such as those inorganic fibers that are derived from glass; silicates, such as neosilicates, sorosilicates, inosilicates (e.g., calcium inosilicates, such as wollastonite; calcium magnesium inosilicates, such as tremolite; calcium magnesium iron inosilicates, such as actinolite; magnesium iron inosilicates, such as anthophyllite; etc.), phyllosilicates (e.g., aluminum phyllosilicates, such as palygorskite), tectosilicates, etc.; sulfates, such as calcium sulfates (e.g., dehydrated or anhydrous gypsum); mineral wools (e.g., rock or slag wool); and so forth. Glass fibers are particularly suitable for use in the present invention, such as those formed from E-glass, A-glass, C-glass, D-glass, AR-glass, R-glass, S1-glass, S2-glass, etc., as well as mixtures thereof. If desired, the glass fibers may be provided with a sizing agent or other coating as is known in the art.
The fibers may have any desired cross-sectional shape, such as circular, flat, etc. In certain embodiments, it may be desirable to employ fibers having a relatively flat cross-sectional dimension in that they have an aspect ratio (i.e., cross-sectional width divided by cross-sectional thickness) of from about 1.5 to about 10, in some embodiments from about 2 to about 8, and in some embodiments, from about 3 to about 5. When such flat fibers are employed in a certain concentration, they may further improve the mechanical properties of the molded part without having a substantial adverse impact on the melt viscosity of the polymer composition. The fibers may, for example, have a nominal width of from about 1 to about 50 micrometers, in some embodiments from about 5 to about 50 micrometers, and in some embodiments, from about 10 to about 35 micrometers. The fibers may also have a nominal thickness of from about 0.5 to about 30 micrometers, in some embodiments from about 1 to about 20 micrometers, and in some embodiments, from about 3 to about 15 micrometers. Further, the fibers may have a narrow size distribution. That is, at least about 60% by volume of the fibers, in some embodiments at least about 70% by volume of the fibers, and in some embodiments, at least about 80% by volume of the fibers may have a width and/or thickness within the ranges noted above. In a molded part, the volume average length of the fibers may be from about 10 to about 500 micrometers, in some embodiments from about 100 to about 400 micrometers, and in some embodiments, from about 150 to about 350 micrometers.
In addition to the components noted above, the polymer composition may also contain a variety of other optional components to help improve its overall properties. In one embodiment, for instance, a siloxane polymer may be employed in the polymer composition. Such siloxane polymer(s) typically constitute from about 0.05 to about 10 parts, in some embodiments from about 0.1 to about 8 parts, and in some embodiments, from about 0.5 to about 5 parts by weight per 100 parts by weight of the polyarylene sulfide(s). For example, siloxane polymer(s) may constitute from about 0.05 wt.% to about 15 wt.%, in some embodiments from about 0.5 wt.% to about 10 wt.%, and in some embodiments, from about 1 wt.% to about 8 wt.% of the polymer composition. Without intending to be limited by theory, it is believed that the siloxane polymer can, among other things, improve the processing of the composition, such as by providing better mold filling, internal lubrication, mold release, etc. Further, it is also believed that the siloxane polymer is less likely to migrate or diffuse to the surface of the composition, which further minimizes the likelihood of phase separation and further assists in dampening impact energy. The siloxane polymer generally has a high molecular weight, such as a weight average molecular weight of about 100,000 grams per mole or more, in some embodiments about 200,000 grams per mole or more, and in some embodiments, from about 500,000 grams per mole to about 2,000,000 grams per mole. The siloxane polymer may also have a relatively high kinematic viscosity at 25° C., such as about 10,000 centistokes or more, in some embodiments about 30,000 centistokes or more, and in some embodiments, from about 50,000 to about 50 × 106 centistokes, such as from about 1 ×106 to 50×106 centistokes. The viscosity of a siloxane polymer can be determined according to ASTM D445-21.
Any of a variety of high molecular weight siloxane polymers may generally be employed in the polymer composition. A high molecular weight siloxane polymer generally includes siloxane-based monomer residue repeating units. As used herein, “siloxane” denotes a monomer residue repeat unit having the structure:
where R1 and R2 are independently hydrogen or a hydrocarbyl moiety, which is known as an “M” group in silicone chemistry.
The silicone may include branch points such as
which is known as a “Q” group in silicone chemistry, or
which is known as “T” group in silicone chemistry.
As used herein, the term “hydrocarbyl” denotes a univalent group formed by removing a hydrogen atom from a hydrocarbon (e.g., alkyl groups, such as ethyl, or aryl groups, such as phenyl). In one or more embodiments, a siloxane monomer residue can be any dialkyl, diaryl, dialkaryl, or diaralkyl siloxane, having the same or differing alkyl, aryl, alkaryl, or aralkyl moieties. In an embodiment, each of R1 and R2 is independently a C1 to C20, C1, to C12, or C1 to C6 alkyl (e.g., methyl, ethyl, propyl, butyl, etc.), aryl (e.g., phenyl), alkaryl, aralkyl, cycloalkyl (e.g., cyclopentyl), arylenyl, alkenyl, cycloalkenyl (e.g., cyclohexenyl), alkoxy (e.g., methoxy), etc., as well as combinations thereof. In various embodiments, R1 and R2 can have the same or a different number of carbon atoms. In various embodiments, the hydrocarbyl group for each of R1 and R2 is an alkyl group that is saturated and optionally straight-chain. Additionally, the alkyl group in such embodiments can be the same for each of R1 and R2 of a polymer chain. Non-limiting examples of alkyl groups suitable for use in R1 and R2 include methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, isobutyl, t-butyl, or combinations of two or more thereof.
Additionally, the siloxane polymer can contain various terminating groups as an R1 and/or R2 group, such as vinyl groups, hydroxyl groups, hydrides, isocyanate groups, epoxy groups, acid groups, halogen atoms, alkoxy groups, acyloxy groups, ketoximate groups, amino groups, amido groups, acid amido groups, amino-oxy groups, mercapto groups, alkenyloxy groups, alkoxyalkoxy groups, or aminoxy groups as well as combinations thereof. Additionally, a polymer composition can include a mixture of two or more siloxane polymers.
In some embodiments, a high molecular weight siloxane polymer can be proved by copolymerizing multiple siloxane polymers having a low weight average molecular weight (e.g., a molecular weight of less than 100,000 grams per mole) with polysiloxane linkers. In one particular embodiment, for instance, the resin may be formed by copolymerizing one or more low molecular siloxane polymer(s) with a linear polydiorganosiloxane linker, such as described in U.S. Pat. No. 6,072,012 to Juen, et al. A substantially linear polydiorganosiloxane linker may have the following general formula:
In certain embodiments, the siloxane polymer may be provided in the form of a masterbatch that includes a carrier resin. The carrier resin may, for instance, constitute from about 0.05 wt.% to about 15 wt.%, in some embodiments from about 0.1 wt.% to about 10 wt.%, and in some embodiments, from about 0.5 wt.% to about 8 wt.% of the polymer composition. Any of a variety of carrier resins may be employed, such as polyolefins (ethylene polymer, propylene polymers, etc.), polyamides, etc. In one embodiment, for example, the carrier resin is an ethylene polymer. The ethylene polymer may be a copolymer of ethylene and an α-olefin, such as a C3-C20 α-olefin or C3-C12 α-olefin. Suitable α-olefins may be linear or branched (e.g., one or more C1-C3 alkyl branches, or an aryl group). Specific examples include 1-butene; 3-methyl-1-butene; 3,3-dimethyl-1-butene; 1-pentene; 1-pentene with one or more methyl, ethyl or propyl substituents; 1-hexene with one or more methyl, ethyl or propyl substituents; 1-heptene with one or more methyl, ethyl or propyl substituents; 1-octene with one or more methyl, ethyl or propyl substituents; 1-nonene with one or more methyl, ethyl or propyl substituents; ethyl, methyl or dimethyl-substituted 1-decene; 1-dodecene; and styrene. Particularly desired α-olefin comonomers are 1-butene, 1-hexene and 1-octene. The ethylene content of such copolymers may be from about 60 mole% to about 99 mole%, in some embodiments from about 80 mole% to about 98.5 mole%, and in some embodiments, from about 87 mole% to about 97.5 mole%. The α-olefin content may likewise range from about 1 mole% to about 40 mole%, in some embodiments from about 1.5 mole% to about 15 mole%, and in some embodiments, from about 2.5 mole% to about 13 mole%. The density of the ethylene polymer may vary depending on the type of polymer employed, but generally ranges from about 0.85 to about 0.96 grams per cubic centimeter (g/cm3). Polyethylene “plastomers”, for instance, may have a density in the range of from about 0.85 to about 0.91 g/cm3. Likewise, “linear low density polyethylene” (LLDPE) may have a density in the range of from about 0.91 to about 0.940 g/cm3; “low density polyethylene” (LDPE) may have a density in the range of from about 0.910 to about 0.940 g/cm3; and “high density polyethylene” (HDPE) may have density in the range of from about 0.940 to about 0.960 g/cm3, such as determined in accordance with ASTM D792. Some non-limiting examples of high molecular weight siloxane polymer masterbatches that may be employed include, for instance, those available from Dow Corning under the trade designations MB50-001, MB50-002, MB50-313, MB50-314 and MB50-321.
If desired, an organosilane compound may also be employed in the polymer composition, such as in an amount of from about 0.1 to about 8 parts, in some embodiments from about 0.3 to about 5 parts, and in some embodiments, from about 0.5 to about 3 parts by weight per 100 parts by weight of the polyarylene sulfide(s). For example, organosilane compounds can constitute from about 0.01 wt.% to about 3 wt.%, in some embodiments from about 0.02 wt.% to about 2 wt.%, and in some embodiments, from about 0.05 to about 1 wt.% of the polymer composition. The organosilane compound may, for example, be any alkoxysilane as is known in the art, such as vinlyalkoxysilanes, epoxyalkoxysilanes, aminoalkoxysilanes, mercaptoalkoxysilanes, and combinations thereof. In one embodiment, for instance, the organosilane compound may have the following general formula:
wherein,
Some representative examples of organosilane compounds that may be included in the mixture include mercaptopropyl trimethyoxysilane, mercaptopropyl triethoxysilane, aminopropyl triethoxysilane, aminoethyl triethoxysilane, aminopropyl trimethoxysilane, aminoethyl trimethoxysilane, ethylene trimethoxysilane, ethylene triethoxysilane, ethyne trimethoxysilane, ethyne triethoxysilane, aminoethylaminopropyltrimethoxysilane, 3-aminopropyl triethoxysilane, 3-aminopropyl trimethoxysilane, 3-aminopropyl methyl dimethoxysilane or 3-aminopropyl methyl diethoxysilane, N-(2-aminoethyl)-3-aminopropyl trimethoxysilane, N-methyl-3-aminopropyl trimethoxysilane, N-phenyl-3-aminopropyl trimethoxysilane, bis(3-aminopropyl) tetramethoxysilane, bis(3-aminopropyl) tetraethoxy disiloxane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-phenyl-y-aminopropyltrimethoxysilane, γ-diallylaminopropyltrimethoxysilane, γ-diallylaminopropyltrimethoxysilane, etc., as well as combinations thereof. Particularly suitable organosilane compounds are 3-aminopropyltriethoxysilane and 3-mercaptopropyltrimethoxysilane.
The polymer composition may also contain a heat stabilizer. By way of example, the heat stabilizer can be a phosphite stabilizer, such as an organic phosphite. For example, suitable phosphite stabilizers include monophosphites and diphosphites, wherein the diphosphite has a molecular configuration that inhibits the absorption of moisture and/or has a relatively high Spiro isomer content. For instance, a diphosphite stabilizer may be selected that has a spiro isomer content of greater than 90%, such as greater than 95%, such as greater than 98%. Specific examples of such diphosphite stabilizers include, for instance, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, mixtures thereof, etc. When employed, heat stabilizers typically constitute from about 0.1 wt.% to about 3 wt.%, and in some embodiments, from about 0.2 wt.% to about 2 wt.% of the composition.
A nucleating agent may also be employed to further enhance the crystallization properties of the composition. One example of such a nucleating agent is an inorganic crystalline compound, such as boron-containing compounds (e.g., boron nitride, sodium tetraborate, potassium tetraborate, calcium tetraborate, etc.), alkaline earth metal carbonates (e.g., calcium magnesium carbonate), oxides (e.g., titanium oxide, aluminum oxide, magnesium oxide, zinc oxide, antimony trioxide, etc.), silicates (e.g., talc, sodium-aluminum silicate, calcium silicate, magnesium silicate, etc.), salts of alkaline earth metals (e.g., calcium carbonate, calcium sulfate, etc.), and so forth. Boron nitride (BN) has been found to be particularly beneficial when employed in the polymer composition of the present invention. Boron nitride exists in a variety of different crystalline forms (e.g., h-BN - hexagonal, c-BN — cubic or spharlerite, and w-BN -wurtzite), any of which can generally be employed in the present invention. The hexagonal crystalline form is particularly suitable due to its stability and softness.
If desired, a crosslinking system may also be employed in combination with any optional impact modifier(s) to help further improve the strength and flexibility of the composition under a variety of different conditions. In such circumstances, a crosslinked product may be formed from a crosslinkable polymer composition that contains the polyarylene sulfide(s), in conjunction with one or more of impact modifier(s), siloxane polymer(s), filler(s) and crosslinking system as well as any other additives. When employed, such a crosslinking system, which may contain one or more crosslinking agents, typically constitutes from about 0.1 to about 15 parts, in some embodiments from about 0.2 to about 10 parts, and in some embodiments, from about 0.5 to about 5 parts per 100 parts of the polyarylene sulfide(s), as well as from about 0.05 wt.% to about 15 wt.%, in some embodiments from about 0.1 wt.% to about 10 wt.%, and in some embodiments, from about 0.2 wt.% to about 5 wt.% of the polymer composition. Through the use of such a crosslinking system, the compatibility and distribution of the polyarylene sulfide and impact modifier can be significantly improved. For example, the impact modifier is capable of being dispersed within the polymer composition in the form of discrete domains of a nano-scale size. For example, the domains may have an average cross-sectional dimension of from about 1 to about 1000 nanometers, in some embodiments from about 5 to about 800 nanometers, in some embodiments from about 10 to about 500 nanometers. The domains may have a variety of different shapes, such as elliptical, spherical, cylindrical, plate-like, tubular, etc. Such improved dispersion can result in either better mechanical properties or allow for equivalent mechanical properties to be achieved at lower amounts of impact modifier.
Any of a variety of different crosslinking agents may generally be employed within the crosslinking system. In one embodiment, for instance, the crosslinking system may include a metal carboxylate. Without intending to be limited by theory, it is believed that the metal atom in the carboxylate can act as a Lewis acid that accepts electrons from the oxygen atom located in a functional group (e.g., epoxy functional group) of the impact modifier. Once it reacts with the carboxylate, the functional group can become activated and can be readily attacked at either carbon atom in the three-membered ring via nucleophilic substitution, thereby resulting in crosslinking between the chains of the impact modifier. The metal carboxylate is typically a metal salt of a fatty acid. The metal cation employed in the salt may vary, but is typically a divalent metal, such as calcium, magnesium, lead, barium, strontium, zinc, iron, cadmium, nickel, copper, tin, etc., as well as mixtures thereof. Zinc is particularly suitable. The fatty acid may generally be any saturated or unsaturated acid having a carbon chain length of from about 8 to 22 carbon atoms, and in some embodiments, from about 10 to about 18 carbon atoms. If desired, the acid may be substituted. Suitable fatty acids may include, for instance, lauric acid, myristic acid, behenic acid, oleic acid, palmitic acid, stearic acid, ricinoleic acid, capric acid, neodecanoic acid, hydrogenated tallow fatty acid, hydroxy stearic acid, the fatty acids of hydrogenated castor oil, erucic acid, coconut oil fatty acid, etc., as well as mixtures thereof. Metal carboxylates typically constitute from about 0.05 wt.% to about 5 wt.%, in some embodiments from about 0.1 wt.% to about 2 wt.%, and in some embodiments, from about 0.2 wt.% to about 1 wt.% of the polymer composition.
The crosslinking system may also employ a crosslinking agent that is “multi-functional” to the extent that it contains at least two reactive, functional groups. Such a multi-functional crosslinking reagent may serve as a weak nucleophile, which can react with activated functional groups on the impact modifier (e.g., epoxy functional groups). The multi-functional nature of such molecules enables them to bridge two functional groups on the impact modifier, effectively serving as a curing agent. The multi-functional crosslinking agents generally include two or more reactively functional terminal moieties linked by a bond or a non-polymeric (non-repeating) linking component. By way of example, the crosslinking agent can include a di-epoxide, poly-functional epoxide, diisocyanate, polyisocyanate, polyhydric alcohol, water-soluble carbodiimide, diamine, diol, diaminoalkane, multi-functional carboxylic acid, diacid halide, etc. Multi-functional carboxylic acids and amines are particularly suitable. Specific examples of multi-functional carboxylic acid crosslinking agents can include, without limitation, isophthalic acid, terephthalic acid, phthalic acid, 1,2-di(p-carboxyphenyl)ethane, 4,4′-dicarboxydiphenyl ether, 4,4′-bisbenzoic acid, 1,4- or 1,5-naphthalene dicarboxylic acids, decahydronaphthalene dicarboxylic acids, norbornene dicarboxylic acids, bicyclooctane dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid (both cis and trans), 1,4-hexylenedicarboxylic acid, adipic acid, azelaic acid, dicarboxyl dodecanoic acid, succinic acid, maleic acid, glutaric acid, suberic acid, azelaic acid and sebacic acid. The corresponding dicarboxylic acid derivatives, such as carboxylic acid diesters having from 1 to 4 carbon atoms in the alcohol radical, carboxylic acid anhydrides or carboxylic acid halides may also be utilized. In certain embodiments, aromatic dicarboxylic acids are particularly suitable, such as isophthalic acid or terephthalic acid.
When employed, multi-functional crosslinking agents typically constitute from about 50 wt.% to about 95 wt.%, in some embodiments from about 60 wt.% to about 90 wt.%, and in some embodiments, from about 70 wt.% to about 85 wt.% of the crosslinking system, while the metal carboxylates typically constitute from about 5 wt.% to about 50 wt.%, in some embodiments from about 10 wt.% to about 40 wt.%, and in some embodiments, from about 15 wt.% to about 30 wt.% of the crosslinking system. For example, the multi-functional crosslinking agents may constitute from about 0.1 wt.% to about 10 wt.%, in some embodiments from about 0.2 wt.% to about 5 wt.%, and in some embodiments, from about 0.5 wt.% to about 3 wt.% of the polymer composition. Of course, in certain embodiments, the composition may be generally free of multi-functional crosslinking agents, or the crosslinking system may be generally free of metal carboxylates.
Still other components that can be included in the composition may include, for instance, particulate fillers (e.g., talc, mica, etc.), antimicrobials, pigments (e.g., black pigments), antioxidants, stabilizers, surfactants, waxes, flow promoters, solid solvents, flame retardants, and other materials added to enhance properties and processability.
The manner in which the thermoplastic polymer, impact modifier, fibrous filler, and various other optional additives are combined may vary as is known in the art. For instance, the materials may be supplied either simultaneously or in sequence to a melt processing device that dispersively blends the materials. Batch and/or continuous melt processing techniques may be employed. For example, a mixer/kneader, Banbury mixer, Farrel continuous mixer, single-screw extruder, twin-screw extruder, roll mill, etc., may be utilized to blend and melt process the materials. One particularly suitable melt processing device is a co-rotating, twin-screw extruder (e.g., Leistritz co-rotating fully intermeshing twin screw extruder). Such extruders may include feeding and venting ports and provide high intensity distributive and dispersive mixing. For example, the components may be fed to the same or different feeding ports of a twin-screw extruder and melt blended to form a substantially homogeneous melted mixture. Melt blending may occur under high shear/pressure and heat to ensure sufficient dispersion. For example, melt processing may occur at a temperature of from about 100° C. to about 500° C., and in some embodiments, from about 150° C. to about 300° C. Likewise, the apparent shear rate during melt processing may range from about 100 seconds-1 to about 10,000 seconds, and in some embodiments, from about 500 seconds-1 to about 1,500 seconds-1. Of course, other variables, such as the residence time during melt processing, which is inversely proportional to throughput rate, may also be controlled to achieve the desired degree of homogeneity.
If desired, one or more distributive and/or dispersive mixing elements may be employed within the mixing section of the melt processing unit. Suitable distributive mixers may include, for instance, Saxon, Dulmage, Cavity Transfer mixers, etc. Likewise, suitable dispersive mixers may include Blister ring, Leroy/Maddock, CRD mixers, etc. As is well known in the art, the mixing may be further increased in aggressiveness by using pins in the barrel that create a folding and reorientation of the polymer melt, such as those used in Buss Kneader extruders, Cavity Transfer mixers, and Vortex Intermeshing Pin mixers. The speed of the screw can also be controlled to improve the characteristics of the composition. For instance, the screw speed can be about 400 rpm or less, in one embodiment, such as between about 200 rpm and about 350 rpm, or between about 225 rpm and about 325 rpm. In one embodiment, the compounding conditions can be balanced so as to provide a polymer composition that exhibits improved properties. For example, the compounding conditions can include a screw design to provide mild, medium, or aggressive screw conditions. For example, system can have a mildly aggressive screw design in which the screw has one single melting section on the downstream half of the screw aimed towards gentle melting and distributive melt homogenization. A medium aggressive screw design can have a stronger melting section upstream from the filler feed barrel focused more on stronger dispersive elements to achieve uniform melting. Additionally, it can have another gentle mixing section downstream to mix the fillers. This section, although weaker, can still add to the shear intensity of the screw to make it stronger overall than the mildly aggressive design. A highly aggressive screw design can have the strongest shear intensity of the three. The main melting section can be composed of a long array of highly dispersive kneading blocks. The downstream mixing section can utilize a mix of distributive and intensive dispersive elements to achieve uniform dispersion of all type of fillers. The shear intensity of the highly aggressive screw design can be significantly higher than the other two designs. In one embodiment, a system can include a medium to aggressive screw design with relatively mild screw speeds (e.g., between about 200 rpm and about 300 rpm).
The crystallization temperature of the resulting polymer composition (prior to being formed into a shaped part) may be about 250° C. or less, in some embodiments from about 100° C. to about 245° C., and in some embodiments, from about 150° C. to about 240° C. The melting temperature of the polymer composition may also range from 140° C. to about 380° C., in some embodiments from about 200° C. to about 360° C., in some embodiments from about 250° C. to about 320° C., and in some embodiments, from about 260° C. to about 300° C. The melting and crystallization temperatures may be determined as is well known in the art using differential scanning calorimetry in accordance with ISO Test No. 11357-3:2018.
A shaped part may be formed from the polymer composition using a variety of different techniques. Suitable techniques may include, for instance, injection molding, low-pressure injection molding, extrusion compression molding, gas injection molding, foam injection molding, low-pressure gas injection molding, low-pressure foam injection molding, gas extrusion compression molding, foam extrusion compression molding, extrusion molding, foam extrusion molding, compression molding, foam compression molding, gas compression molding, etc. For example, an injection molding system may be employed that includes a mold within which the polymer composition may be injected. The time inside the injector may be controlled and optimized so that polymer matrix is not pre-solidified. When the cycle time is reached and the barrel is full for discharge, a piston may be used to inject the composition to the mold cavity. Compression molding systems may also be employed. As with injection molding, the shaping of the polymer composition into the desired article also occurs within a mold. The composition may be placed into the compression mold using any known technique, such as by being picked up by an automated robot arm. The temperature of the mold may be maintained at or above the solidification temperature of the polymer composition for a desired time period to allow for solidification. The molded product may then be solidified by bringing it to a temperature below that of the melting temperature. The resulting product may be de-molded. The cycle time for each molding process may be adjusted to suit the polymer composition, to achieve sufficient bonding, and to enhance overall process productivity.
As indicated above, the unique properties of the polymer composition can more readily allow it to be integrally formed with a metal component having a vastly different thermal coefficient of expansion. Thus, if desired, the polymer composition may be employed in a composite structure that contains a metal component that is integrally formed and in contact with a resinous component that includes the polymer composition of the present invention. This may be accomplished using a variety of techniques, such as by an insert molding process in which the polymer composition is molded (e.g., injection molded) onto a portion or the entire surface of the metal component. The metal component may contain any of a variety of different metals, such as aluminum, stainless steel, magnesium, nickel, chromium, copper, titanium, and alloys thereof. Due to its unique properties, the polymer composition can adhere to the metal component by flowing within and/or around surface indentations or pores of the metal component. To improve adhesion, the metal component may optionally be pretreated to increase the degree of surface indentations and surface area. This may be accomplished using mechanical techniques (e.g., sandblasting, grinding, flaring, punching, molding, etc.) and/or chemical techniques (e.g., etching, anodic oxidation, etc.). In addition to pretreating the surface, the metal component may also be preheated at a temperature close to, but below the melt temperature of the polymer composition. This may be accomplished using a variety of techniques, such as contact heating, radiant gas heating, infrared heating, convection or forced convection air heating, induction heating, microwave heating or combinations thereof. In any event, the polymer composition is generally injected into a mold that contains the optionally preheated metal component.
As previously mentioned, the polymer composition, shaped part, and/or composite structure are particularly beneficial for use in components of an electric vehicle. Referring to
The powertrain 110 may also contain at least one power electronics module 126 that is connected to the battery assembly 124 (also commonly referred to as a battery pack) and that may contain a power converter (e.g., converter, etc., as well as combinations thereof). The power electronics module 126 is typically electrically connected to the electric machines 114 and provides the ability to bi-directionally transfer electrical energy between the battery assembly 124 and the electric machines 114. For example, the battery assembly 124 may provide a DC voltage while the electric machines 114 may require a three-phase AC voltage to function. The power electronics module 126 may convert the DC voltage to a three-phase AC voltage as required by the electric machines 114. In a regenerative mode, the power electronics module 126 may convert the three-phase AC voltage from the electric machines 114 acting as generators to the DC voltage required by the battery assembly 124. The battery assembly 124 may also provide energy for other vehicle electrical systems. For example, the powertrain may employ a DC/DC converter module 128 that converts the high voltage DC output from the battery assembly 124 to a low voltage DC supply that is compatible with other vehicle loads, such as compressors and electric heaters. In a typical vehicle, the low-voltage systems are electrically connected to an auxiliary battery 130 (e.g., 12V battery). A battery energy control module (BECM) 133 may also be present that is in communication with the battery assembly 124 that acts as a controller for the battery assembly 124 and may include an electronic monitoring system that manages temperature and charge state of each of the battery cells. The battery assembly 124 may also have a temperature sensor 131, such as a thermistor or other temperature gauge. The temperature sensor 131 may be in communication with the BECM 133 to provide temperature data regarding the battery assembly 124. The temperature sensor 131 may also be located on or near the battery cells within the traction battery 124. It is also contemplated that more than one temperature sensor 131 may be used to monitor temperature of the battery cells.
In certain embodiments, the battery assembly 124 may be recharged by an external power source 136, such as an electrical outlet. The external power source 136 may be electrically connected to electric vehicle supply equipment (EVSE) that regulates and manages the transfer of electrical energy between the power source 36 and the vehicle 112. The EVSE 138 may have a charge connector 140 for plugging into a charge port 134 of the vehicle 112. The charge port 134 may be any type of port configured to transfer power from the EVSE 138 to the vehicle 112 and may be electrically connected to a charger or on-board power conversion module 132. The power conversion module 132 may condition the power supplied from the EVSE 138 to provide the proper voltage and current levels to the battery assembly 124. The power conversion module 132 may interface with the EVSE 138 to coordinate the delivery of power to the vehicle 112.
The polymer composition described herein can be included in various components of an electric vehicle as illustrated in
The manner in which a busbar connects to individual battery cells of a battery assembly 124, such as shown in
Of course, a busbar may be provided in any suitable shape and size. For instance, a busbar may be used as a template for placing the individual battery cells so that they are uniform in each battery assembly manufactured. In such an embodiment, a busbar may hold individual batteries of a battery assembly 124 in place during the manufacturing process and thermal padding or injection-housings, which can be formed of a polymer composition as described herein, can be added without causing the individual battery cells to shift out of position.
Apart from busbars, other components may also employ the polymer composition of the present invention. For instance,
Another component of an electric vehicle as may incorporate the polymer compositions as described is an inverter system, one exemplary embodiment of which is illustrated in
An inverter system can include several components that can incorporate a polymer composition as disclosed including, without limitation, the EMI filter apparatus 325, e.g., as a housing and/or internal support structures, an EMI filter card 340, the bus bars 310, as well as connectors employed within the system. For example, an electrical connector that includes the polymer composition as described herein may be employed in an inverter system as in
Referring to
Although by no means required, the first connector portion 202 may also include an identification mark 210 secured to or defined by the first protective member 212. The second connecting portion 204 may also optionally define an alignment window 220 sized according to the identification mark 210 to more easily determine when the portions are fully mated. For instance, the identification mark 210 may not be readable unless blockers 221 cover a portion of the identification mark 210. Optionally, the second connecting portion 204 may include a supplemental mark 224 located adjacent to the alignment window 220.
Systems that can employ the polymer composition of the present invention are in no way limited to only electrical systems. For example, a thermal management system can also beneficially incorporate the polymer composition. A thermal management system of an electric vehicle can generally include multiple different subsystems such as, without limitation, a power train subsystem, a refrigeration subsystem, a battery cooling subsystem, and a heating, ventilation, and cooling (HVAC) subsystem. In some embodiments, one or more subsystems of a thermal management system may in fluid communication with one another, thus allowing hot heat transfer medium to flow from the high temperature circuit into the low temperature circuit, and cooler heat transfer medium to flow from the low temperature circuit into the high temperature circuit.
By way of example,
One example of a component of a heat management system as may incorporate the polymer composition of the invention is a coolant pump, e.g., an electric water pump, an example of which is illustrated in
The present invention may be better understood with reference to the following examples.
Melt Viscosity: The melt viscosity (Pa-s) may be determined in accordance with ISO 11443:2021 at a shear rate of 400 s-1 and using a Dynisco LCR7001 capillary rheometer. The rheometer orifice (die) may have a diameter of 1 mm, length of 20 mm, L/D ratio of 20.1, and an entrance angle of 180°. The diameter of the barrel may be 9.55 mm + 0.005 mm and the length of the rod was 233.4 mm. The melt viscosity is typically determined at a temperature of 310° C.
Tensile Modulus, Tensile Stress at Break, and Tensile strain at Break: Tensile properties may be tested according to ISO 527-2/1A:2019 (technically equivalent to ASTM D638-14). Modulus and strength measurements may be made on the same test strip sample having a length of 80 mm, thickness of 10 mm, and width of 4 mm. The testing temperature may be 23° C., and the testing speeds may be 5 mm/min for tensile strength and tensile strain at break, and 1 mm/min for tensile modulus.
Flexural Modulus and Flexural Stress: Flexural properties may be tested according to ISO 178:2019 (technically equivalent to ASTM D790-10). This test may be performed on a 64 mm support span. Tests may be run on the center portions of uncut ISO 3167 multi-purpose bars. The testing temperature may be 23° C. and the testing speed may be 2 mm/min.
Izod notched impact strength may be determined according to ISO 180:2019. Specimens were cut from the center of a multi-purpose bar using a single tooth milling machine. Testing temperature was 23° C.
Notched Charpy Impact Strength: Charpy properties may be tested according to ISO Test No. ISO 179-1:2010) (technically equivalent to ASTM D256-10, Method B). This test may be run using a Type 1 specimen size (length of 80 mm, width of 10 mm, and thickness of 4 mm). When testing the notched impact strength, the notch may be a Type A notch (0.25 mm base radius). Specimens may be cut from the center of a multi-purpose bar using a single tooth milling machine. The testing temperature may be 23° C. or -30° C.
Comparative Tracking Index (“CTI”): The comparative tracking index (CTI) may be determined in accordance with International Standard IEC 60112-2003 to provide a quantitative indication of the ability of a composition to perform as an electrical insulating material under wet and/or contaminated conditions. In determining the CTI rating of a composition, two electrodes are placed on a molded test specimen. A voltage differential is then established between the electrodes while a 0.1% aqueous ammonium chloride solution is dropped onto a test specimen. The maximum voltage at which five (5) specimens withstand the test period for 50 drops without failure is determined. The test voltages range from 100 to 600 V in 25 V increments. The numerical value of the voltage that causes failure with the application of fifty (50) drops of the electrolyte is the “comparative tracking index.” The value provides an indication of the relative track resistance of the material. According to UL746A, a nominal part thickness of 3 mm is considered representative of performance at other thicknesses.
Thermal Shock Resistance: To test thermal shock resistance, four (4) types of sample components are initially formed using the molds and inserts shown in
Referring to
A set of twenty (20) sample components may be formed using each of the molds described above. The sample components may then be subjected to a first heating cycle within a thermal shock chamber having a hot zone and a cold zone, such as those commercially available under the name “ShockEvent T/120/V2” from Weisstechnik. The hot zone may be heated to a temperature of 140° C. and the cold zone may be cooled to a temperature of -40° C. To initiate the first heating cycle, the sample components are placed within the hot zone for 30 minutes and then a product carrier within the chamber moves the sample components from the hot zone to the cold zone for an additional 30 minutes. In this manner, the total time of the first cycle is 1 hour. 24 cycles are conducted each day and 1 hour for each cycle. During the first two weeks, the sample components are visually observed for cracking once a day, and thereafter, the sample components are visually observed for cracking twice per week until all twenty (20) samples crack or a full set of cycles is achieved, which may be either 1,500 or 3,000 cycles depending on the testing protocol. When the first sample cracks, the number of cycles achieved prior to cracking is recorded as the “thermal shock resistance value.” If a full set of cycles (1,500 or 3,000) is achieved without all samples cracking, the “thermal shock resistance value” is simply recorded as “>1,500” or “>3,000”, depending on the particular testing protocol.
Comparative Examples 1-2 were melt mixed using a 32 mm Coperion co-rotating, fully-intermeshing, twin-screw extruder and include various concentrations of a polyarylene sulfide, glass fibers, lubricant (Glycolube P), and colorant. The formulations of each Comparative Examples are set forth in more detail in the table below.
Examples 1-2 were melt mixed using a 32 mm Coperion co-rotating, fully-intermeshing, twin-screw extruder and include various concentrations of a polyarylene sulfide, impact modifier, glass fibers, siloxane polymer, organosilane, lubricant (Glycolube), and a colorant. The impact modifier was a random copolymer of ethylene and glycidyl methacrylate having 8 wt.% glycidyl methacrylate content and a melt flow index of 5 g/10 min at 190° C. The siloxane polymer was an UHMW functionalized siloxane polymer provided as a masterbatch at 50% siloxane content and 50% resin content. The organosilane was 3-aminopropyltriethoxysilane. The formulations of each Example are set forth in more detail in the table below.
Following formation, the samples were tested for a variety of thermal shock resistance, CTI, and a variety of other physical characteristics. The results are set forth below.
Example 1 was also re-formulated (Example 1a) and tested again for various physical properties before and after heat aging in air at 240° C. for 1,000 hrs.
These and other modifications and variations of the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention so further described in such appended claims.
The present application is based upon and claims priority to U.S. Provisional Pat. Application Serial No. 63/361,948 having a filing date of Feb. 1, 2022; U.S. Provisional Pat. Application Serial No. 63/309,695, having a filing date of Feb. 14, 2022; U.S. Provisional Pat. Application Serial No. 63/330,807 having a filing date of Apr. 14, 2022; and U.S. Provisional Pat. Application Serial No. 63/358,904 having a filing date of Jul. 7, 2022, which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63358904 | Jul 2022 | US | |
| 63330807 | Apr 2022 | US | |
| 63309695 | Feb 2022 | US | |
| 63361948 | Feb 2022 | US |
