Liquid crystal polymer composition, article and manufacturing method

Abstract

A polymer composition comprising at least 20 wt.% of a liquid crystal polymer (“LCP”); 10 wt.% to 40 wt.% of flat glass fibers and 15 wt.% to 50 wt.% of boron nitride and / or zinc oxide is described herein. It was surprisingly discovered that a polymer composition comprising LCP in combination with flat glass fibers and boron nitride and / or zinc oxide has improved thermal conductivity and flexural properties compared to a similar polymer composition having round glass fibers instead of flat glass fibers.

Description

Technology Field

[0001] Related applications

[0002] This application claims priority to U.S. No. 63 / 105416 filed October 26, 2020 and European No. 21150658.9 filed January 8, 2021, the entire contents of which are incorporated herein by reference for all purposes.

[0003] Technology field

[0004] A polymer composition is provided. The polymer composition has excellent thermal conductivity and comprises a liquid crystal polymer (“LCP”), flat glass fibers, and one or both of boron nitride and zinc oxide. An article comprising the polymer composition is provided, as well as a method for manufacturing the polymer composition and the article. Background Technology

[0005] As the power density of electrical components increases, the thermal output of those components also increases, at least in part, due to the resistance of current carriers. As a result, heat accumulation within the electrical components increases significantly. For example, there is a continuous demand to increase the power density of electric motors for electric vehicles (e.g., cars, motorcycles, boats, and airplanes), driven by rising consumer demand for high-performance vehicles. However, as power density increases, heat accumulation within and around the electric motor increases, which can lead to a significant decrease in motor efficiency.

[0006] In a first embodiment, a liquid crystal polymer (“LCP”) formed from the polycondensation of terephthalic acid, an aromatic diol, a first aromatic dicarboxylic acid, and an aromatic hydrocarboxylic acid monomer is provided; 10 wt.% to 40 wt.% of flat glass fibers; and a polymer composition comprising boron nitride and / or zinc oxide having a total concentration of 15 wt.% to 50 wt.% of boron nitride and zinc oxide. In some embodiments, the aromatic diol is 4,4'-biphenol, the aromatic hydrocarboxylic acid is 4-hydroxybenzoic acid, and the first aromatic dicarboxylic acid is isophthalic acid.

[0007] In some embodiments, the polymer composition does not contain zinc oxide. In some embodiments, the polymer composition does not contain boron nitride. In some embodiments, the polymer composition comprises boron nitride and zinc oxide. In one such embodiment, the relative concentration of boron nitride to zinc oxide is 0.5 to 2.

[0008] In some embodiments, the polymer composition has a through-plane thermal conductivity of 0.20 W / mK to 0.9 W / mK when measured according to ASTM E1461-13. In some embodiments, the polymer composition has a flexural strength of 100 MPa to 250 MPa according to ASTM D790. In some embodiments, the polymer composition has a flexural strain of 100 MPa to 190 MPa when measured according to ASTM D790. In some embodiments, the polymer composition has 100 s when measured according to ASTM D3835 -1 At a shear rate of 90 Pa·s to 300 Pa·s; 500 s -1 At a shear rate of 35 Pa·s to 150 Pa·s; or 1000 s -1 It has an apparent viscosity of 25 Pa·s to 100 Pa·s at a shear rate.

[0009] In some embodiments, the polymer composition does not contain round glass fibers.

[0010] In another embodiment, an article comprising a polymer composition is provided, wherein the article is an electrical component. In some embodiments, the article is an electric motor component. In some embodiments, the article is a slot liner. In some embodiments, the article is selected from the group consisting of automotive components, aerospace components and marine components. Specific details for implementing the invention

[0011] A polymer composition comprising at least 20 wt.% of a liquid crystal polymer (“LCP”); 10 wt.% to 40 wt.% of flat glass fibers and 15 wt.% to 50 wt.% of boron nitride and / or zinc oxide is provided herein. It has been surprisingly discovered that a polymer composition comprising LCP in combination with flat glass fibers and boron nitride and / or zinc oxide has improved thermal conductivity and flexural properties compared to a similar polymer composition having round glass fibers instead of flat glass fibers. As used herein, weight percentage (“wt.%”) refers to the total weight of the polymer composition unless otherwise explicitly stated.

[0012] Any description, even if described with respect to a specific embodiment, is applicable to and interchangeable with other embodiments of the present disclosure; where an element or component is said to be included in and / or selected from a list of elements or components cited herein, in the relevant embodiments explicitly considered herein, the element or component may also be any one of the individual elements or components cited herein, or may be selected from a group consisting of any two or more of the elements or components explicitly listed; any element or component mentioned in the list of elements or components may be omitted from said list; and where a numerical range is cited herein by an endpoint, it includes all numbers included within the mentioned range, as well as endpoints and equivalents of the range.

[0013] Unless specifically limited otherwise, the term "alkyl" as used herein, as well as derivative terms such as "alkoxy," "acyl," and "alkylthio," includes straight-chain, branched-chain, and cyclic moiety within its scope. Examples of alkyl groups are methyl, ethyl, 1-methylethyl, propyl, 1,1-dimethylethyl, and cyclopropyl. Unless specifically stated otherwise, each alkyl and aryl group may be unsubstituted or, without limitation, substituted with one or more substituents selected from halogen, hydroxy, sulfo, C1-C6 alkoxy, C1-C6 alkylthio, C1-C6 acyl, formyl, cyano, C6-C15 aryloxy, or C6-C15 aryl, provided that the substituents are stereocompatible and satisfy the chemical bonding and strain energy rules. The terms "halogen" or "halo" include fluorine, chlorine, bromine, and iodine, with fluorine being preferred.

[0014] Similarly, unless specifically limited otherwise, the term “aryl” means a phenyl, indanyl, or naphthyl group. An aryl group may include one or more alkyl groups, in which case it is sometimes referred to as an “alkylaryl”; for example, it may consist of an aromatic group and two C1-C6 groups (e.g., methyl or ethyl). An aryl group may also include one or more heteroatoms, for example, N, O, or S, in which case it is sometimes referred to as a “heteroaryl” group; these heteroaromatic rings may be fused to other aromatic systems. Such heteroaromatic rings include, but are not limited to, furanyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, isoxazolyl, oxazolyl, thiazolyl, isothiazolyl, pyridyl, pyridazyl, pyrimidyl, pyrazinyl, and triazinyl ring structures. The aryl or heteroaryl substituent may be unsubstituted or, without limitation, substituted with one or more substituents selected from halogen, hydroxy, C1-C6 alkoxy, sulfo, C1-C6 alkylthio, C1-C6 acyl, formyl, cyano, C6-C15 aryloxy, or C6-C15 aryl, provided that the substituents are stereocompatible and the chemical bonding and strain energy rules are satisfied.

[0015] Polymer composition

[0016] The polymer composition comprises LCP; 10 wt.% to 40 wt.% flat glass fibers and 15 wt.% to 50 wt.% boron nitride and / or zinc oxide. The polymer composition containing LCP in combination with flat glass fibers and boron nitride and / or zinc oxide surprisingly exhibited improved thermal conductivity and flexural properties compared to a similar polymer composition having round glass fibers instead of flat glass fibers. Additionally, in some embodiments, the polymer composition had an apparent viscosity particularly desirable for injection molding of thin-wall articles.

[0017] The polymer composition has remarkably improved thermal conductivity. As mentioned above, particularly in high-power density electrical component articles (e.g., electric motors for electric vehicles), heat output increases significantly, causing heat to accumulate inside and around the electrical components. Therefore, improved cooling must be provided. The polymer composition described herein has significantly improved thermal conductivity that helps conduct heat away from electric motor components. Of course, the same applies to all articles that carry significant current or have high power density requirements (e.g., power supplies). In some embodiments, the polymer composition has a through-plane thermal conductivity of at least 0.20 watts / meter-Kelvin ("W / mK"), at least 0.25 W / mK, at least 0.3 W / mK, at least 0.35 W / mK, at least 0.4 W / mK, at least 0.45 W / mK, at least 0.5 W / mK, at least 0.55 W / mK, or at least 0.6 W / mK. In some embodiments, the polymer composition has a through-plane thermal conductivity of 0.9 W / mK or less or 0.85 W / mK or less. In some embodiments, the polymer composition has a through-plane thermal conductivity of 0.2 W / mK to 0.9 W / mK, 0.25 W / mK to 0.9 W / mK, 0.3 W / mK to 0.9 W / mK, 0.35 W / mK to 0.9 W / mK, 0.4 W / mK to 0.9 W / mK, 0.45 W / mK to 0.9 W / mK, 0.5 W / mK to 0.9 W / mK, 0.55 W / mK to 0.9 W / mK, or 0.6 W / mK to 0.9 W / mK. In some embodiments, the polymer composition is 0.2 W / mK to 0.85 W / mK, 0.25 W / mK to 0.85 W / mK, 0.3 W / mK to 0.85 W / mK, 0.35 W / mK to 0.85 W / mK, 0.4 W / mK to 0.85 W / mK, 0.45 W / mK to 0.85 W / mK, 0.5 W / mK to 0.85 W / mK, 0.It has a through-surface thermal conductivity of 55 W / mK to 0.85 W / mK or 0.6 W / mK to 0.85 W / mK. The through-surface thermal conductivity can be measured as described in the Examples section.

[0018] The polymer composition also exhibited improved flexural properties. In some embodiments, the polymer composition has a tensile strength at break ("tensile strength") of 100 MPa to 250 MPa, 120 MPa to 250 MPa, 130 MPa to 250 MPa, 140 MPa to 250 MPa, or 150 MPa to 250 MPa. In some embodiments, the polymer composition has a tensile strength of 100 MPa to 250 MPa, 120 MPa to 220 MPa, 130 MPa to 220 MPa, 140 MPa to 220 MPa, or 150 MPa to 220 MPa. In some embodiments, the polymer composition has a tensile strength of 100 MPa to 200 MPa, 120 MPa to 200 MPa, 130 MPa to 200 MPa, 140 MPa to 200 MPa, or 150 MPa to 200 MPa. In some embodiments, the polymer composition has a tensile strength of 100 MPa to 190 MPa, 120 MPa to 190 MPa, 130 MPa to 190 MPa, 140 MPa to 190 MPa, or 150 MPa to 190 MPa. In some embodiments, the polymer composition has a tensile strain at break ("tensile strain") of 1% to 3%, 1.5% to 3%, or 1.8% to 3%. In some embodiments, the polymer composition has a tensile strain of 1% to 2.5%, 1.5% to 2.5%, or 1.8% to 2.5%. Tensile strength and tensile elongation can be measured as described in the Examples section.

[0019] In some embodiments, the polymer composition is 100 seconds -1 ("s -1At a shear rate of 100 Pa·s, the polymer composition has an apparent viscosity ("η") of 90 Pa·s to 300 Pa·s, 120 Pa·s to 300 Pa·s, or 150 Pa·s to 300 Pa·s. In some embodiments, the polymer composition has 100 s -1 At a shear rate, it has η of 90 Pa·s to 250 Pa·s, 120 Pa·s to 250 Pa·s, or 150 Pa·s to 250 Pa·s. In some embodiments, the polymer composition is 500 s -1 At a shear rate, it has η of 35 Pa·s to 150 Pa·s, 70 Pa·s to 150 Pa·s, 35 Pa·s to 120 Pa·s, or 70 Pa·s to 120 Pa·s. In some embodiments, the polymer composition is 1000 s -1 At a shear rate of 25 Pa·s to 100 Pa·s, 50 Pa·s to 100 Pa·s, 25 Pa·s to 90 Pa·s, or 50 Pa·s to 90 Pa·s, η is 25 Pa·s to 100 Pa·s, 25 Pa·s to 90 Pa·s, or 50 Pa·s to 90 Pa·s. η can be measured as described in the Examples section.

[0020] In some embodiments, the polymer composition has a melting temperature ("Tm") of at least 300°C, at least 320°C, or at least 340°C. In some embodiments, the polymer composition has a Tm of 430°C or less, 410°C or less, or 400°C or less. In some embodiments, the polymer composition has a Tm of 300°C to 430°C, 320°C to 410°C, or 340°C to 400°C. Tm can be measured according to ASTM D3418.

[0021] Liquid crystal polymer

[0022] LCP is formed by the polycondensation of terephthalic acid, an aromatic diol, a first aromatic dicarboxylic acid distinct from terephthalic acid, and an aromatic hydroxycarboxylic acid monomer. In some embodiments, at least one of the first aromatic dicarboxylic acid and the aromatic hydroxycarboxylic acid does not have a naphthyl group.

[0023] In some embodiments, the aromatic diol is represented by a chemical formula selected from the group of the following formulas:

[0024] [Chemical Formula 1]

[0025] HO-Ar1-OH, and

[0026] [Chemical Formula 2]

[0027] HO-Ar2-T1-Ar3-OH,

[0028] Here, Ar1 to Ar3 are halogens, C1-C 15 Alkyl and C6-C 15 Independently selected C6-C that is optionally substituted with one or more substituents selected from the group consisting of aryls 30 It is an aryl group; T1 is bonded, O, S, -SO2-, -C(=O)- and C1-C 15 It is selected from the group consisting of alkyls. In some embodiments, the aromatic diol is selected from the group consisting of 1,3-dihydroxybenzene, 1,4-dihydroxybenzene, 2,5-biphenyldiol, 4,4'-biphenol, 4,4'-(propane-2,2-diyl)diphenol, 4,4'-(ethane-1,2-diyl)diphenol, 4,4'-methylenediphenol, bis(4-hydroxyphenyl)methanolone, 4,4'-oxydiphenol, 4,4'-sulfonyldiphenol, 4,4'-thiodiphenol, naphthalene-2,6-diol, and naphthalene-1,5-diol. Preferably, the aromatic diol is 4,4'-biphenol.

[0029] In some embodiments, the first aromatic dicarboxylic acid is represented by a chemical formula independently selected from the group of the following formulas:

[0030] [Chemical Formula 3]

[0031] HOOC-Ar1-COOH, and

[0032] [Chemical Formula 4]

[0033] HOOC-Ar2-T2-Ar3-COOH,

[0034] Here, Ar1 to Ar3 are given as above and selected independently; T2 is selected from the group consisting of bond, O and S. In some embodiments, the first aromatic dicarboxylic acid is selected from the group consisting of isophthalic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-oxydibenzoic acid, 4,4'-(ethylenedioxy)dibenzoic acid, 4,4'-sulfandiyldibenzoic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid and naphthalene-2,3-dicarboxylic acid. Preferably, the first aromatic dicarboxylic acid is selected from the group consisting of isophthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, and naphthalene-2,3-dicarboxylic acid. Most preferably, the first aromatic dicarboxylic acid is isophthalic acid.

[0035] In some embodiments, the aromatic hydroxycarboxylic acid is represented by a chemical formula selected from the group consisting of:

[0036] [Chemical Formula 5]

[0037] HO-Ar1-COOH, and

[0038] [Chemical Formula 6]

[0039] HO-Ar2-Ar3-COOH,

[0040] Here, Ar1 to Ar3 are provided above and are selected independently. In some embodiments, the aromatic hydroxycarboxylic acid is selected from the group consisting of 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 6-hydroxy-1-naphthoic acid, 2-hydroxy-1-naphthoic acid, 3-hydroxy-2-naphthoic acid, 1-hydroxy-2-naphthoic acid, 5-hydroxy-1-naphthoic acid, and 4'-hydroxy-[1,1'-biphenyl]-4-carboxylic acid. Preferably, the aromatic hydroxycarboxylic acid is selected from the group consisting of 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 6-hydroxy-1-naphthoic acid, 2-hydroxy-1-naphthoic acid, 3-hydroxy-2-naphthoic acid, 1-hydroxy-2-naphthoic acid, and 5-hydroxy-1-naphthoic acid. Most preferably, the aromatic hydroxycarboxylic acid is 4-hydroxybenzoic acid.

[0041] In some embodiments, the LCP formed from the aforementioned monomer is a repeating unit R LCP1 to R LCP4 It has. Repetition unit R LCP1 is represented by the following chemical formula:

[0042] [Chemical Formula 7]

[0043] ;

[0044] Repetition unit R LCP2 is represented by one of the following chemical formulas:

[0045] [Chemical Formula 8]

[0046] -[-O-Ar1-O-]-, and

[0047] [Chemical Formula 9]

[0048] -[-O-Ar2-T1-Ar3-O-]-;

[0049] Repetition unit R LCP3 is represented by one of the following chemical formulas:

[0050] [Chemical Formula 10]

[0051] -[-OC-Ar1-CO-]-, and

[0052] [Chemical Formula 11]

[0053] -[-OC-Ar2-T2-Ar3-CO-]-; and

[0054] Repetition unit R LCP4 is represented by one of the following chemical formulas:

[0055] [Chemical Formula 12]

[0056] -[-O-Ar1-CO-]-, and

[0057] [Chemical Formula 13]

[0058] -[-O-Ar2-Ar3-CO-]-.

[0059] Here, Ar1 to Ar3, T1 and T2 are provided above and selected independently. Those skilled in the art will recognize R according to Formula 7. LCP1 Formed from this terephthalic acid; R according to chemical formulas 8 and 9 LCP2 are formed from monomers according to chemical formulas 1 and 2, respectively; and R according to chemical formulas 10 and 11. LCP3 are formed from monomers according to chemical formulas 3 and 4, respectively; and R according to chemical formulas 12 and 13. LCP4 It will be recognized that is formed from monomers according to chemical formulas 5 and 6. As such, the selection of Ar1 to Ar3, T1 and T2 for the monomers of chemical formulas 1 to 6 also includes the repeating unit R LCP2 to R LCP4 Select Ar1 to Ar3, T1, and T2 for . Preferably, the repeating unit R LCP1 to R LCP4 It is formed from the polycondensation of terephthalic acid, 4,4'-biphenol, isophthalic acid, and 4-hydroxybenzoic acid, respectively.

[0060] In some implementations, the repetition unit R LCP1 to R LCP4The total concentration of is at least 50 mol%, at least 60 mol%, at least 70 mol%, at least 80 mol%, at least 90 mol%, at least 95 mol%, at least 99 mol%, or at least 99.9 mol%. In some embodiments, the concentration of terephthalic acid is 5 mol% to 30 mol%, preferably 10 mol% to 20 mol%. In some embodiments, the concentration of aromatic diol is 10 mol% to 30 mol%, preferably 15 mol% to 25 mol%. In some embodiments, the concentration of the first aromatic dicarboxylic acid is 1 mol% to 20 mol%, preferably 1 mol% to 10 mol%. In some embodiments, the concentration of aromatic hydrocarboxylic acid is 35 mol% to 80 mol%, preferably 45 mol% to 75 mol%, most preferably 50 mol% to 17 mol%. In one embodiment, R LCP1 to R LCP4 Each is derived from terephthalic acid, 4,4'-biphenol, isophthalic acid, and 4-hydroxybenzoic acid, respectively, wherein the concentration range for each repeating unit is within the range given above. The mol% of each repeating unit used herein refers to the total moles of repeating units in the polymer unless otherwise explicitly indicated. For clarity, “derived from” refers to repeating units formed from the polycondensation of the cited monomers, for example, as described above regarding the relationship between formulas 1 to 6 and 8 to 13.

[0061] In some embodiments, the LCP has a Tm of at least 310°C, at least 320°C, or at least 330°C. In some embodiments, the LCP has a Tm of 390°C or less, 380°C or less, or 370°C or less. In some embodiments, the LCP has a Tm of 310°C to 390°C, 320°C to 380°C, or 330°C to 370°C.

[0062] In some embodiments, the LCP has a number average molecular weight ("Mn") of at least 5,000 g / mol. In some embodiments, the LCP has a Mn of 20,000 g / mol or less. In some embodiments, the LCP has a Mn of 5,000 g / mol to 20,000 g / mol. The number average molecular weight Mn can be determined by gel permeation chromatography (GPC) using a hexafluoroisopropanol solvent and a poly(methyl methacrylate) standard according to ASTM D5296.

[0063] In some embodiments, the LCP concentration in the polymer composition is at least 20 wt.%, at least 30 wt.%, at least 35 wt.%, or at least 40 wt.%. In some embodiments, the LCP concentration in the polymer composition is 80 wt.% or less, 75 wt.% or less, or 70 wt.% or less. In some embodiments, the LCP concentration in the polymer composition is 30 wt.% to 80 wt.%, 30 wt.% to 75 wt.%, or 30 wt.% to 70 wt.%. In some embodiments, the LCP concentration in the polymer composition is 35 wt.% to 80 wt.%, 35 wt.% to 75 wt.%, or 35 wt.% to 70 wt.%. In some embodiments, the LCP concentration in the polymer composition is 40 wt.% to 80 wt.%, 40 wt.% to 75 wt.%, or 40 wt.% to 70 wt.%.

[0064] The LCP described herein can be manufactured by any conventional method suitable for the synthesis of LCP.

[0065] Boron nitride or zinc oxide

[0066] The polymer composition comprises boron nitride and / or zinc oxide. In some embodiments, the polymer composition comprises boron nitride or zinc oxide. In one such embodiment, the polymer composition comprises boron nitride and is not zinc oxide. In another embodiment, the polymer composition comprises zinc oxide and is not boron nitride. In some embodiments, the polymer composition comprises both boron nitride and zinc oxide. Unless otherwise expressly stated as used herein, a component being “not” means that the concentration of the component in the polymer composition is 1 wt.% or less, 0.5 wt.% or less, 0.1 wt.% or less, or 0.05 wt.% or less.

[0067] The total concentration of boron nitride and zinc oxide in the polymer composition is 15 to 50 wt.%. In some embodiments, the total concentration of boron nitride and zinc oxide is at least 20 wt.%. In some embodiments, the total concentration of boron nitride and zinc oxide is 45 wt.% or less, 40 wt.% or less. In some embodiments, the total concentration of boron nitride and zinc oxide is 15 wt.% to 45 wt.% or 15 wt.% to 40 wt.%. In some embodiments, the total concentration of boron nitride and zinc oxide is 20 wt.% to 50 wt.%, 20 wt.% to 45 wt.%, or 20 wt.% to 40 wt.%. In an embodiment comprising both boron nitride and zinc oxide, the relative concentration of boron nitride to zinc oxide (weight of boron nitride in the polymer composition / weight of zinc oxide in the polymer composition) is 0.5 to 2, 0.75 to 1.3, 0.80 to 1.2, or 0.90 to 1.1. In an embodiment comprising boron nitride or zinc oxide, the boron nitride concentration or the zinc oxide concentration is each within the same range as provided above with respect to the total concentration of boron nitride and zinc oxide.

[0068] Flat glass fiber

[0069] The polymer composition further comprises flat glass fibers. Glass fibers are silica-based glass compounds containing various metal oxides that can be customized to make various types of glass. The primary oxide is silica in the form of silica sand; other oxides, such as calcium, sodium, and aluminum, are incorporated to lower the melting temperature and inhibit crystallization. Glass fibers may be added as infinite fibers or cut glass fibers. Any type of glass fiber, such as A, C, D, E, M, S, R, and T glass fibers (as described in the literature [Additives for Plastics Handbook, 2nd ed., John Murphy, chapter 5.2.3, pages 43-48]), or any mixture thereof or a mixture thereof may be used. For example, R, S, and T glass fibers are high-modulus glass fibers that typically have an elastic modulus of at least 76, preferably at least 78, more preferably at least 80, and most preferably at least 82 GPa when measured according to ASTM D2343.

[0070] E, R, S, and T glass fibers are well known in the art. They are particularly well described in the literature [Fiberglass and Glass Technology, Wallenberger, Frederick T.; Bingham, Paul A. (Eds.), 2010, XIV, chapter 5, pages 197-225]. R, S, and T glass fibers are essentially composed of oxides of silicon, aluminum, and magnesium. Specifically, these glass fibers typically contain 62 to 75 wt.% SiO2, 16 to 28 wt.% Al2O3, and 5 to 14 wt.% MgO, based on the total weight of the glass fibers. Unlike general E-glass fibers, which are widely used in polymer compositions, R, S, and T glass fibers contain less than 10 wt.% CaO, based on the total weight of the glass compositions.

[0071] Generally, the glass fiber has an aspect ratio defined as the average ratio between a length of at least 5, at least 10, at least 20, or at least 50, and a maximum width and thickness. In some embodiments, the glass fiber has an average length of 3 mm to 50 mm. In some such embodiments, the glass fiber has an average length of 3 mm to 10 mm, 3 mm to 8 mm, 3 mm to 6 mm, or 3 mm to 5 mm. In alternative embodiments, the glass fiber has an average length of 10 mm to 50 mm, 10 mm to 45 mm, 10 mm to 35 mm, 10 mm to 30 mm, 10 mm to 25 mm, or 15 mm to 25 mm. The average length of the glass fiber may be taken as the average length of the glass fiber before being incorporated into the polymer composition, or as the average length of the glass fiber in the polymer composition.

[0072] Flat glass fiber is a glass fiber having a non-circular cross-section, including egg-shaped, elliptical, or rectangular shapes.

[0073] In some embodiments, the glass fiber has a maximum cross-sectional diameter of at least 15 μm, preferably at least 20 μm, more preferably at least 22 μm, and much more preferably at least 25 μm. Additionally or alternatively, in some embodiments, the glass fiber has a maximum cross-sectional diameter of up to 40 μm, preferably up to 35 μm, more preferably up to 32 μm, and much more preferably up to 30 μm. In some embodiments, the glass fiber has a maximum cross-sectional diameter of 15 μm to 35 μm, preferably 20 to 30 μm, and more preferably 25 μm to 29 μm. In some embodiments, the glass fiber has a minimum cross-sectional diameter of at least 4 μm, preferably at least 5 μm, more preferably at least 6 μm, and much more preferably at least 7 μm. Additionally or alternatively, in some embodiments, the glass fiber has a cross-sectional shortest diameter of up to 25 μm, preferably up to 20 μm, more preferably up to 17 μm, and much more preferably up to 15 μm. In some embodiments, the glass fiber has a cross-sectional shortest diameter of 5 μm to 20 μm, preferably 5 μm to 15 μm, and more preferably 7 μm to 11 μm. In some embodiments, the glass fiber has an aspect ratio of at least 2, preferably at least 2.2, more preferably at least 2.4, and much more preferably at least 3. The aspect ratio is defined as the ratio of the longest diameter to the shortest diameter in the cross-section of the glass fiber. In some embodiments, the glass fiber has an aspect ratio of up to 8, preferably up to 6, and more preferably up to 4. In some embodiments, the glass fiber has an aspect ratio of 2 to 6 or 2.2 to 4.

[0074] The shape, length, cross-sectional diameter, and aspect ratio of a glass fiber cross-section can be easily determined using an optical microscope. For example, the aspect ratio of a fiber cross-section is determined by measuring the maximum (width) and minimum (height) dimensions of the fiber cross-section using a Euromex optical microscope and image analysis software (Image Focus 2.5) and dividing the first number by the second number.

[0075] In some embodiments, the glass fiber has an elastic modulus of at least 76 GPa, preferably at least 78, more preferably at least 80, much more preferably at least 82, and most preferably at least 84 GPa when measured according to ASTM C1557-03. In some embodiments, the glass fiber has a tensile strength of at least 3.5 GPa, preferably at least 3.6, more preferably at least 3.7, much more preferably at least 3.8, and most preferably at least 3.9 GPa when measured according to ASTM C1557-03. These levels of elastic modulus and tensile strength are typically reached when using the specific chemical composition of the glass used to manufacture the glass fiber. The glass is a silica-based glass compound containing several metal oxides that can be customized to make various types of glass. The main oxide is silica in the form of silica sand; other oxides such as calcium, sodium, and aluminum are incorporated to lower the melting temperature and hinder crystallization. It is well known in the art that when using glass containing a large amount of Al2O3, glass fibers derived therefrom exhibit a high elastic modulus. Specifically, such glass fibers typically contain 55 to 75 wt.% SiO2, 16 to 28 wt.% Al2O3, and 5 to 14 wt.% MgO based on the total weight of the glass composition. Unlike general E-glass fibers widely used in polymer compositions, high-modulus glass fibers contain less than 5 wt.%, preferably less than 1 wt.%, of B2O3 based on the total weight of the glass composition.

[0076] The concentration of flat glass fibers in the polymer composition is 10 wt.% to 40 wt.%. In some embodiments, the concentration of flat glass fibers in the polymer composition is 10 wt.% to 35 wt.%, 10 wt.% to 30 wt.%, 15 wt.% to 40 wt.%, 15 wt.% to 35 wt.%, or 15 wt.% to 30 wt.% based on the total weight of the polymer composition.

[0077] additives

[0078] In some embodiments, the polymer composition also includes an additive selected from the group consisting of additional reinforcing agents, toughening agents, plasticizers, colorants, pigments, antistatic agents, dyes, lubricants, heat stabilizers, light stabilizers, flame retardants, nucleating agents, and antioxidants.

[0079] Various additional reinforcing agents may be added to the polymer composition. The additional reinforcing agents may be selected from fibrous and particulate reinforcing agents. Fibrous reinforcing agents are considered herein to be materials having length, width, and thickness, wherein the average length is much greater than both the width and thickness. Generally, such materials have an aspect ratio defined as the average ratio between a length of at least 5, at least 10, at least 20, or at least 50, and a maximum width and thickness. In some embodiments, the fibrous reinforcing agent has an average length of 3 mm to 50 mm. In some of these embodiments, the fibrous reinforcing agent has an average length of 3 mm to 10 mm, 3 mm to 8 mm, 3 mm to 6 mm, or 3 mm to 5 mm. In an alternative embodiment, the fibrous reinforcement has an average length of 10 mm to 50 mm, 10 mm to 45 mm, 10 mm to 35 mm, 10 mm to 30 mm, 10 mm to 25 mm, or 15 mm to 25 mm. The average length of the fibrous reinforcement may be considered as the average length of the fibrous reinforcement before being incorporated into the polymer composition or as the average length of the fibrous reinforcement in the polymer composition. Examples of fibrous reinforcement include, but are not limited to, additional glass fibers (e.g., round glass fibers), carbon fibers, synthetic polymer fibers, aramid fibers, aluminum fibers, titanium fibers, magnesium fibers, boron carbide fibers, rock wool fibers, and steel fibers. Round glass fibers are glass fibers having a substantially circular cross-section (e.g., a cross-section having a vertical axis within a cross-sectional plane with a length difference of 5% or less, 1% or less, or 0.5% or less). Fine particle reinforcing agents include, but are not limited to, talc, mica, kaolin, calcium carbonate, calcium silicate, magnesium carbonate, and wollastonite.

[0080] In some embodiments, the reinforcing agent concentration in the polymer composition is at least 15 wt.%, at least 20 wt.%, at least 25 wt.%, or at least 30 wt.%. In some embodiments, the reinforcing agent concentration is 45 wt.% or less. In some embodiments, the reinforcing agent concentration is 20 wt.% to 45 wt.% or 30 wt.% to 45 wt.%.

[0081] In some embodiments, the polymer composition has no reinforcing agent. In some embodiments, the polymer composition has no additional glass fibers. In some embodiments, the polymer composition has no round glass fibers. The absence of a reinforcing agent (e.g., additional glass fibers or round glass fibers) means that the concentration of the reinforcing agent is less than 10 wt.%, less than 5 wt.%, less than 1 wt.%, or less than 0.5 wt.%.

[0082] The polymer composition may also include a toughening agent. The toughening agent is generally a low Tg polymer with a glass transition temperature (Tg) below room temperature, below 0°C, or even below -25°C. Because of the low Tg, the toughening agent is typically an elastomer at room temperature. The toughening agent may be a functionalized polymer backbone.

[0083] The polymer backbone of the toughening agent may be selected from polyethylene and copolymers thereof, for example, ethylene-butene; ethylene-octene; polypropylene and copolymers thereof; polybutene; polyisoprene; ethylene-propylene rubber (EPR); ethylene-propylene-diene monomer rubber (EPDM); ethylene-acrylate rubber; butadiene-acrylonitrile rubber, ethylene-acrylic acid (EAA), ethylene-vinyl acetate (EVA); acrylonitrile-butadiene-styrene rubber (ABS), block copolymer styrene ethylene butadiene styrene (SEBS); block copolymer styrene butadiene styrene (SBS); methacrylate-butadiene-styrene (MBS) type core-shell elastomers, or a mixture of one or more of the above.

[0084] When a toughening agent is functionalized, the functionalization of the backbone may occur from the copolymerization of monomers containing the functionalization or from the grafting of the polymer backbone with additional components.

[0085] Specific examples of functionalized toughening agents are, in particular, terpolymers of ethylene, acrylate, and glycidyl methacrylate; copolymers of ethylene and butyl ester acrylate; copolymers of ethylene, butyl ester acrylate, and glycidyl methacrylate; ethylene-maleic anhydride copolymers; EPR grafted with maleic anhydride; styrene copolymer grafted with maleic anhydride; SEBS copolymer grafted with maleic anhydride; styrene-acrylonitrile copolymer grafted with maleic anhydride; and ABS copolymer grafted with maleic anhydride.

[0086] In some embodiments, the toughening agent concentration is at least 1 wt.%, at least 2 wt.%, or at least 3 wt.%. Additionally or alternatively, in some embodiments, the toughening agent concentration is 30 wt.% or less, 20 wt.% or less, 15 wt.% or less, or 10 wt.% or less.

[0087] The polymer composition may also include other conventional additives commonly used in the art, including plasticizers, colorants, pigments (e.g., black pigments such as carbon black and nigrosin), antistatic agents, dyes, lubricants (e.g., linear low-density polyethylene, calcium or magnesium stearate or sodium montanate), heat stabilizers, light stabilizers, flame retardants, nucleating agents, and antioxidants.

[0088] Preparation of polymer compositions

[0089] The polymer composition can be prepared by melt blending LCP and specific components (e.g., flat glass fibers and boron nitride or zinc oxide) and any other additives.

[0090] Any suitable melt-blending method known in the art may be used to mix the polymer component and the non-polymer component. For example, the polymer component and the non-polymer component may be fed into a melt mixer, a stirrer, a single-screw or twin-screw kneader, such as a single-screw extruder or a twin-screw extruder, or a Banbury mixer, and the addition step may involve adding all components at once or adding them gradually in a batch. When adding the polymer component and the non-polymer component gradually in a batch, a portion of the polymer component and / or the non-polymer component is added first, and then melt-mixed with the remaining polymer component and non-polymer component subsequently added until a properly mixed composition is obtained. If the reinforcing agent exhibits a long physical form (e.g., long glass fiber), the reinforced composition may be prepared using pultrusion extrusion.

[0091] Items and Applications

[0092] The polymer composition may preferably be incorporated into an article. The article may be particularly used in an application environment where a thin-wall article is formed (e.g., injection molding) from the polymer composition.

[0093] The thin-walled articles used herein are articles having a portion having a maximum thickness (measured along a line perpendicular to the surface) of 1 mm or less, 0.9 mm or less, 0.8 mm or less, or 0.7 mm or less. Preferably, the portion is at least 1 mm 2 , at least 10 mm 2 , at least 100 mm 2 , or at least 1000 mm 2 It is an area on the surface of an article having an area of ​​.

[0094] In some embodiments, the article is an automotive component, an aerospace component, or a marine component (including but not limited to boats and jet skis). In some embodiments including but not limited to the above-mentioned embodiments, the article is an electrical component (e.g., an electric vehicle component). In some embodiments, the electrical component contacts or contains a current carrier. In some embodiments including but not limited to the above-mentioned embodiments, the article is an electric motor component (e.g., an electric vehicle motor component). In some embodiments, the article is a slot liner. The slot liner is incorporated into the stator or rotor of an electric motor (including a generator). The slot liner provides insulation between the stator core or motor core and the stator winding or rotor winding, respectively. As mentioned above, the polymer composition described herein is particularly desirable for high power density motor applications due to at least significantly improved through-plane thermal conductivity. For clarity, the article described above may be a thin-walled article or a non-thin-walled article. Preferably, the article is a thin-walled article.

[0095] Melt extrusion involves pushing a molten polymer or polymer composition through a die or orifice. The molten polymer may be formed during melt-blending as described above, or it may be formed by melting a polymer or polymer composition that has been pre-formed, for example, in the form of pellets. In the case of injection-molded articles, the molten polymer is forced into a mold and solidified before injection (removal from the mold). In some embodiments where the molten polymer is formed by melt-blending (e.g., extrusion), the mold may be directly or indirectly coupled to a melt-blending device (e.g., an extruder) so that the polymer composition may be pressed into the mold before it has cooled significantly. In other embodiments, solid pellets of the polymer or polymer composition may be melted, and a melting device may be directly or indirectly coupled to the mold so that the molten polymer or polymer composition can be fed into the mold. The mold corresponds to the shape of the article to be molded. As mentioned above, the polymer composition has a melt viscosity that is highly desirable for injection-molding applications, particularly in relation to thin-wall articles formed by injection molding.

[0096] The article can be printed from a polymer composition by a process including, for example, an extrusion step of a material in the form of a filament, or a laser sintering step of a material in the form of a powder.

[0097] A method for manufacturing a three-dimensional (3D) object using an additional manufacturing system is also provided, the method comprising the steps of providing a part material comprising a polymer composition and printing a layer of the three-dimensional object from the part material.

[0098] Therefore, the polymer composition may be in the form of a thread or filament used in a 3D printing process, for example, in the fabrication of fused filaments also known as Fused Deposition Modeling (FDM).

[0099] The polymer composition may also be in the form of a powder, for example, substantially spherical powder, which can be used in 3D printing, for example, in a Selective Laser Sintering (SLS) process.

[0100] In the event that the disclosures of any patent, patent application, and publication incorporated herein by reference conflict with the description of this application to the extent that they may obscure the terms, this specification shall prevail.

[0101] Examples

[0102] The following examples demonstrate the film-forming ability and genetic and mechanical performance of the polymer composition.

[0103] The following materials were used in the examples:

[0104] - LCP : Liquid crystal polymer formed from the following monomers: isophthalic acid; terephthalic acid; 4,4'-biphenol, p-hydroxybenzoic acid

[0105] - Flat glass fiber ("FGF") : Commercially available from Nitto Boseki Co., LTD (CSG 3PA-830).

[0106] - Round glass fiber ("RGF") : Commercially obtained from Saint-Gobain (910).

[0107] - slush Trademark name Polymist ® Commercially available as F5A from Solvay Specialty Polymers Italy, SpA.

[0108] - Boron nitride : Commercially available from Momentive (CF600 boron nitride).

[0109] - zinc oxide : Commercially available from Dryteck (Pana-Tetra).

[0110] Example 1: Synthesis of LCP and Sample Formation

[0111] To synthesize LCP, dicarboxylic acid monomers (terephthalic acid (167.0 g, Flint Hills Resources), isophthalic acid (55.7 g, Lotte Chemicals), p-hydroxybenzoic acid (555.5 g, Sanfu), 4,4'-biphenol (201.6 g, SI Group), and acetic anhydride (769.2 g, Aldrich)) were loaded into a 2-L glass reactor. Potassium acetate (0.07 g, Aldrich) and magnesium acetate (0.2 g, Aldrich) were used as catalysts. The mixture was heated to 165°C, and the acetylation reaction was carried out for 1 hour under reflux conditions. Then, heating was continued to 300°C at a rate of 0.5°C per minute while distilling off the acetic acid from the reactor. The prepolymer was discharged and cooled. The material was then ground into a powder for solid-state polymerization. The resin was processed in a rotary oven using the following profile: 1 hour at 220°C, 1 hour at 290°C, and 12 hours at 310°C under continuous nitrogen purging. The resulting polymer resin had a melt viscosity of 60 to 140 Pa-s at 370°C.

[0112] The polymer composition was melt-blended in an extruder to form samples and cut into pellets. Samples for thermal and mechanical tests were formed by injection molding. Sample parameters are shown in Table 1. All values ​​in Table 1 are in wt.% units and are based on the total weight of the polymer composition.

[0113] ingredient C1 E1 E2 E3 E4 E5 E6 C2 C3 C4 C5 FGF 29 20 20 20 20 20 20 RGF 29 20 20 20 LCP 70 39 49 34 59 59 39 70 59 59 39 slush 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Boron nitride 40.00 30.00 20.00 20.00 20.00 20.00 20.00 ZnO 25.00 20.00 20.00 20.00 20.00

[0114] Example 2: Thermal performance, mechanical performance, and rheological performance

[0115] This example demonstrates the thermal, mechanical, and rheological performance of the sample.

[0116] To verify thermal performance, a Netzsch LFA 467 HyperFlash instrument was used, and planar conductivity was measured by the flash method according to ASTM E1461-13, "Standard Test Method for Thermal Diffusivity by the Flash Method." To verify mechanical performance, flexural strength and flexural strain were measured according to ASTM D790. To verify rheological performance, η (apparent viscosity) was measured according to ASTM D3835. The results of the thermal, mechanical, and rheological performance are shown in Table 2.

[0117] characteristic C1 E1 E2 E3 E4 E5 E6 C2 C3 C4 C5 Thermal performance Penetration surface (W / mK) 0.20 0.85 0.54 0.77 0.38 0.25 0.61 0.29 0.35 0.24 0.64 mechanical performance Flexural strength (MPa) 182 117 154 125 151 157 132 173 144 152 131 Flexural strain (%) 2.2 1 1.8 1.0 1.9 1.7 1.1 1.9 1.7 1.6 1 rheological performance Capillary rheology at 370°C Viscosity (Pa-s) at 100 1 / sec 70 234 194 218 155 91 201 132 217 153 324 Viscosity at 500 1 / sec, Pa-s 20 110 71 74 73 37 78 53 99 55 120 Viscosity at 1000 1 / sec, Pa-s 10 85 49 51 55 27 55 38 70 37 82

[0118] Samples with a combination of flat glass fibers and boron nitride showed improved penetration conductivity, flexural strength at break, and flexural strain at break compared to samples with a combination of round glass fibers and boron nitride. Referring to Table 2, a comparison of C1 and E4 demonstrates that adding boron nitride to the LCP composition (E4) filled with flat glass fibers results in a penetration conductivity of 0.38 W / mK, which represents an improvement of approximately 90% compared to a similar LCP composition (C1) without boron nitride. A comparison of C2 and C3 shows that adding boron nitride to the LCP composition (C3) filled with round glass fibers results in a penetration conductivity of only about 0.35 W / mK, which is lower than that for E4 and represents an improvement of only about 21% compared to a similar LCP composition (C2) without boron nitride. In addition, adding boron nitride to E4 compared to C1 and to C3 compared to C2 reduces flexural strength and flexural strain at fracture, but E4 improves flexural strength and flexural strain at fracture compared to C3.

[0119] Similarly, samples with a combination of flat glass fibers and zinc oxide showed improved penetration conductivity, flexural strength at break, and flexural strain at break compared to samples with a combination of round glass fibers and zinc oxide. Referring to Table 2, a comparison of C1 and E5 demonstrates that adding zinc oxide to the LCP composition (E5) filled with flat glass fibers results in a penetration conductivity of 0.25 W / mK, which represents an improvement of about 25% compared to a similar LCP composition (C1) without zinc oxide. A comparison of C2 and C4 shows that adding zinc oxide to the LCP composition (C4) filled with round glass fibers results in a penetration conductivity of only about 0.24 W / mK, which is slightly lower than that for E4 and represents a decrease of about 17% compared to a similar LCP composition (C2) without zinc oxide. In addition, adding zinc oxide to E5 compared to C1 and to C4 compared to C2 reduces flexural strength and flexural strain at fracture, but E5 improves flexural strength and flexural strain at fracture compared to C4.

[0120] In addition, the sample with a combination of flat glass fibers, boron nitride, and zinc oxide had improved flexural properties while maintaining excellent through-plane conductivity compared to the sample with a combination of flat glass fibers and boron nitride alone. Referring to Table 2, a comparison of E1 and E6 shows that the former has higher through-plane conductivity, while the latter shows significantly improved flexural strength at fracture and flexural strain at fracture.

[0121] The above embodiments are for illustrative purposes only and are not limiting. Additional embodiments are within the scope of the invention. Furthermore, while descriptions of specific embodiments are provided, those skilled in the art will recognize that changes in form and detail may be made without departing from the spirit and scope of the invention. Incorporation by reference to the above documents is limited to avoiding subject matter contrary to what is expressly disclosed herein.

Claims

Claim 1 - At least 20 wt.% of a liquid crystal polymer ("LCP") formed by the polycondensation of the following monomers: terephthalic acid; 4,4'-biphenol; isophthalic acid; and 4-hydroxybenzoic acid; - 10 wt.% to 40 wt.% of flat glass fibers; and - boron nitride and zinc oxide, wherein the total concentration of boron nitride and zinc oxide is 15 wt.% to 50 wt.%; and - optionally an additive selected from the group consisting of tougheners, plasticizers, colorants, pigments, antistatic agents, dyes, lubricants, heat stabilizers, light stabilizers, nucleating agents, and antioxidants, wherein the relative concentration of boron nitride to zinc oxide, expressed as weight of boron nitride in the polymer composition / weight of zinc oxide in the polymer composition, is 0.5 to 2. Claim 2 The polymer composition of claim 1, wherein the polymer composition has a through-surface thermal conductivity of 0.20 W / mK to 0.9 W / mK when measured by a laser flash according to ASTM E1461-13. Claim 3 A polymer composition according to claim 1 or 2, wherein the polymer composition has a flexural strength of 100 MPa to 250 MPa in accordance with ASTM D790. Claim 4 A polymer composition according to claim 1 or 2, wherein the polymer composition has a flexural strain of 100 MPa to 190 MPa when measured according to ASTM D790. Claim 5 In claim 1 or 2, the polymer composition is 100 s when measured according to ASTM D3835 -1 At a shear rate of 90 Pa·s to 300 Pa·s; 500 s -1 At a shear rate of 35 Pa·s to 150 Pa·s; or 1000 s -1 A polymer composition having an apparent viscosity of 25 Pa·s to 100 Pa·s at a shear rate. Claim 6 A polymer composition according to claim 1 or 2, wherein the flat glass fiber concentration is 10 wt.% to 30 wt.% based on the total weight of the polymer composition. Claim 7 A polymer composition according to claim 1 or 2, wherein the glass fiber has an aspect ratio defined as the average ratio between the length, maximum width, and thickness of at least 5. Claim 8 delete Claim 9 delete Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete