Method for producing polyester fine powder

Abstract

The present invention relates to a process for preparing fine particles of aromatic copolyesters, which process comprises melt blending an aromatic copolyester with a polyester polymer (PE), cooling the blend, and recovering the particles by dissolving the PE in water. The present invention also relates to aromatic copolyester particles obtained therefrom and to the use of these particles for producing coatings or films.

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 013,005, filed April 21, 2020, and to European Patent Application No. 20187261.1, filed July 22, 2020, the entire contents of both applications being incorporated herein by reference for any purpose.

[0002] The present invention relates to a method for preparing fine particles of aromatic copolyester, comprising melt blending of aromatic copolyester and polyester polymer (PE), cooling of the blend, and recovery of the particles by dissolving the PE in water. The present invention also relates to the aromatic copolyester particles obtained thereby and the use of these particles for manufacturing coatings or films. [Background technology]

[0003] Because spherical resin fine particles have excellent fluidity and adhesive properties, they are used in a variety of applications, such as powder materials for coatings, powder materials for manufacturing molded products, and additives.

[0004] There are several methods available for producing small-sized particle powders. These include traditional techniques such as milling and grinding. In a typical industrial mill, a cylindrical metal drum containing steel balls rotates, and the balls inside collide with the material, crushing it. The material being milled can be cooled, making it more brittle and thus easier to crush. Jet mills can produce micron-sized particles. The grinding action of a jet mill is produced by multiple jets of high-speed gas streams. The energy requirements for this process are high, and therefore favorable for powder production in a viable economic sense. In grinding, solid particles are formed when grinding units of a device rub against each other while solid particles are trapped between them. Other methods such as crushing and cutting are also used to reduce particle size, but they produce articles that are less clear / uniform compared to the two techniques mentioned above. Crushing breaks a solid into smaller particles by impact using a hammer-like tool. A well-known example of a crushing device is a hammer mill, which includes a rotating shaft with a freely swinging hammer mounted in a cage. Inside the cage is a breaker plate against which the material collides, breaking it down into smaller particles. Cutting uses a sharp blade to cut the coarse, solid pieces into smaller ones.

[0005] These techniques (milling, grinding, crushing, and cutting) are well-established and have been successfully used in various types of materials and applications. However, the production of micron-sized polymer particles / powder by these methods has been particularly limited in success with high-performance polymers such as copolyesters and copolyamides, with yields decreasing as the powder size decreases. While particle sizes in the range of 200-300 microns can be prepared, reaching 5-50 microns is challenging, requiring longer processing times and multiple passes, and solubility makes it more expensive with lower yields.

[0006] A method for producing spherical liquid crystal resin fine particles (microspherical bodies) in which a liquid crystal resin is melt-mixed with a matrix resin soluble in a solvent and then the matrix resin is dissolved and removed with the solvent is known.

[0007] For example, Japanese Patent Application Laid-Open No. 2001-064399 discloses melt-kneading a thermoplastic resin composition having a continuous phase of a thermoplastic resin (A) and a dispersed phase of a liquid crystal polyester (B), then extruding from a nozzle, and taking it up at a take-up speed of less than 3.0 micrometers of the resin discharge rate, thereby molding it into a strand shape and cutting it into pellets, or melt-kneading the thermoplastic resin composition and then taking it out as a lump; then immersing the pellets or lump in a solvent that dissolves component (A) but does not dissolve component (B), and as a result, dissolving and removing component (A), and provides a method for producing liquid crystal polyester microspherical bodies. However, even in this case, the obtained polyester particles have an average particle size of about 100 μm.

[0008] International Publication No. 2019 / 240153 pamphlet discloses a similar method including a step of melt-mixing a liquid crystal resin A and a thermoplastic resin B to obtain a composition C (melt-mixing step), and a washing step of stirring the obtained composition C in a certain solvent that dissolves the thermoplastic resin B without dissolving the liquid crystal resin A. Examples of the solvent used in the washing step include nitrobenzene, phenol, toluene, methylene chloride, carbon tetrachloride, methyl ethyl ketone, acetone, dimethylformamide, dimethyl sulfoxide, dimethyl sulfone, tetramethyl sulfone, and tetramethylene sulfoxide. One or more organic solvents selected from the following can be used.

[0009] An exemplary washing step is carried out for 40 to 80 minutes at a temperature in the range of 30 °C to 100 °C using a magnetic stirrer or the like. Then, the solution is filtered using a filter or the like to collect insolubles.

[0010] However, the use of organic solvents in washing requires specific handling, manufacturing standards, and recycling of the solvents in an environmentally friendly manner.

[0011] More recently, an approach has been pursued in which the use of organic solvents is generally avoided in order to secure more environmentally friendly technologies.

[0012] Therefore, there is a felt need for a method of manufacturing fine particles of aromatic copolyesters that avoids the use of organic solvents in order to secure a more environmentally friendly technology that advantageously enables the obtaining of powders with a particle size of ideally about 10 microns.

Summary of the Invention

[0013] Therefore, the present applicant has faced the problem of providing a method for manufacturing aromatic copolyester fine particles having high heat resistance, few impurities, and a spherical shape without using an organic solvent.

[0014] The applicant's achievement is the identification of a type of material (herein called polyester polymer (PE)) that enables the preparation of spherical fine particles of aromatic copolyesters suitable for being processed together with high-temperature aromatic copolyesters and having sufficient thermal stability to be melt-blended with aromatic copolyesters. The PE polymer of the present invention withstands high temperatures, i.e., does not decompose especially at high temperatures, for example above 250°C. In addition, the polyester polymer (PE) can be heated to a temperature of optionally 95°C or less so that it can be dissolved in water. The PE polymer of the present invention, therefore, not only exhibits sufficient thermal stability to be melt-blended with aromatic copolyesters but also exhibits solubility or dispersibility in water, which facilitates and is environmentally friendly for implementing the entire preparation method of aromatic copolyester fine particles.

[0015] In a first aspect, the present invention is a method for preparing fine particles of an aromatic copolyester, comprising the following steps: a) i) at least one aromatic copolyester (P), and ii) - at least one dicarboxylic acid component, - At least one diol component [where at least 2 mol% of the diol component is given by formula (I): H(OC m H 2m ) n -OH (In the formula, m is an integer between 2 and 4, and n varies between 2 and 10.) It is a poly(alkylene glycol) having [the properties of] A polyester polymer (PE) containing units derived from and A step of melt-blending a mixture (M) containing the following: b) A step of processing the mixture (M) obtained in step a) into pellets or strands, c) Optionally, a step of cooling the pellet or strand obtained in step b) at a temperature of less than 80°C, d) A step of bringing the pellets or strands obtained in step b) or c) into contact with water heated to a temperature of 95°C or lower, if applicable. e) A step of recovering fine polymer particles of at least one aromatic copolyester (P), f) Optionally, a step of drying the particles recovered in step e), g) Optionally, a step of sieving the particles obtained in step e) or step f). This provides a method that includes this. [Brief explanation of the drawing]

[0016] [Figure 1] This is a scanning electron microscope (SEM) image of LCP particles. [Figure 2] This is a scanning electron microscope (SEM) image of the particles from Example 1. [Figure 3] This is a scanning electron microscope (SEM) image of the particles from Example 2. [Figure 4] This is a scanning electron microscope (SEM) image of the particles from Example 3. [Figure 5] This is a scanning electron microscope (SEM) image of the particles from Example 4. [Modes for carrying out the invention]

[0017] In relation to the present invention, the use of parentheses "(...)" before and after symbols or numbers that identify a formula or part of a formula is solely for the purpose of better distinguishing the symbols or numbers from the rest of the text, and therefore such parentheses may also be omitted.

[0018] The term "weight percentage (wt%)" indicates the content of a particular component in a mixture, calculated as the ratio between the weight of the component and the total weight of the mixture.

[0019] As used herein, Tm, Tg, and Tc refer to the melting temperature, glass transition temperature, and crystallization temperature, respectively. Tm, Tg, and Tc can be measured using differential scanning calorimetry ("DSC") in accordance with ISO-11357-3.

[0020] Unless otherwise specifically defined, the terms “alkyl,” and their derivatives such as “alkoxy,” “acyl,” and “alkylthio,” as used herein, include linear, branched, and cyclic portions. Examples of alkyl groups are methyl, ethyl, 1-methylethyl, propyl, 1,1-dimethylethyl, and cyclopropyl. Unless otherwise specifically described, each alkyl and aryl group, whether unsubstituted, includes halogen, hydroxyl, sulfo, C1-C6 alkoxy, C1-C6 alkylthio, C1-C6 acyl, formyl, cyano, and C6-C 15 Aryloxy or C6~C 15 The substituents may be substituted with one or more substituents selected from, but not limited to, aryl substituents, provided that the substituents are sterically compatible and the rules of chemical bonding and strain energy are satisfied. The term "halogen" or "halo" includes fluorine, chlorine, bromine, and iodine, with fluorine being preferred.

[0021] Similarly, unless specifically limited, the term “aryl” refers to a phenyl, indanyl, or naphthyl group. An aryl group may contain one or more alkyl groups, in which case it may be called an “alkylaryl” group; for example, it may consist of an aromatic group and two C1-C6 groups (e.g., methyl or ethyl). An aryl group may also contain one or more heteroatoms, for example, N, O, or S, in which case it may be called a “heteroaryl” group; these heteroaromatic rings may condense with 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. Even if unsubstituted, aryl or heteroaryl substituents include halogens, hydroxyl, C1-C6 alkoxy, sulfo, C1-C6 alkylthio, C1-C6 acyl, formyl, cyano, and C6-C. 15 Aryloxy or C6~C 15 The molecule may be substituted with one or more substituents selected from, but not limited to, aryl substituents, provided that the substituents are sterically compatible and the rules for chemical bonding and strain energy are satisfied.

[0022] The method of the present invention is based on melt-blending at least one aromatic copolyester (P) with a water-soluble or water-dispersible polyester (PE) in such a way as to produce fine particles of aromatic copolyester dispersed in a phase made of water-soluble or water-dispersible polyester (PE), for example by adding sufficient mixing energy to form discrete particles. The blend is then cooled, and the particles are recovered by dissolving or dispersing the polyester (PE) in water, which may be heated to a temperature of 95°C or less.

[0023] More generally, step a) in the melt blending of the mixture (M) can be carried out in any suitable device, such as an endless screw mixer or stirrer mixer, e.g., a compounding machine, which is suitable for the temperature required to melt the aromatic copolyester (P). The amount of energy applied to this step can be adjusted to control the size of the polymer particles obtained therefrom. Those skilled in the art can adjust the apparatus (e.g., the geometric shape of the screw) and the parameters of the apparatus (e.g., the rotational speed) to obtain particles of a desired size, for example, with an average diameter varying between about 1 μm and about 500 μm.

[0024] According to a preferred embodiment, step a) is carried out at a temperature above 300°C, for example above 310°C, for example above 320°C, or above 330°C.

[0025] Step b), which involves processing the mixture into pellets or strands, can be carried out by an extrusion process through a die. Step b) is preferably carried out in an extruder equipped with an extrusion die.

[0026] The pellets or strands obtained in step b) may be immediately placed in water to dissolve the polyester (PE) and recover the aromatic copolyester (P) fine particles. Alternatively, the pellets or strands obtained in step b) may be cooled in step c) by any suitable means at a temperature below 80°C, for example below 50°C. In particular, cooling by air or rapid cooling in a liquid, for example in water, may be used.

[0027] Step d) bringing the pellets or strands into contact with water may involve immersing them in water, and optionally in multiple baths of water heated to a temperature of, for example, 95°C or less. This step allows for the dissolution of polyester (PE) to recover aromatic copolyester (P) fine particles.

[0028] The water used in step d) may be supplemented with an acid or base selected from the group consisting of, for example, potassium hydroxide, sodium hydroxide, lithium hydroxide, potassium carbonate, sodium carbonate, lithium carbonate, organic amines, hydrochloric acid, and sulfuric acid. This step allows for the dissolution or dispersion of polyester in order to recover the polymer particles.

[0029] In step e), the recovery of at least one aromatic copolyester (P) fine particles includes washing the particles with fresh water until they preferably do not contain residual polyester (PE) and sufficient purity is obtained.

[0030] The present invention advantageously utilizes water or running water with a neutral pH.

[0031] The steps of the method of the present invention can be carried out in batches or continuously.

[0032] According to one embodiment, steps c) and d) can be performed simultaneously in the same apparatus.

[0033] The method of the present invention may also further include an additional step e) drying the particles, and / or an additional step f) sieving the particles. The drying step can be carried out, for example, in a fluidized bed.

[0034] In this specification, the term "aromatic copolyester" is intended to mean a total aromatic polyester which is a reaction product of at least one aromatic polyol and at least one aromatic dicarboxylic acid.

[0035] Preferably, the aromatic copolyester is an aromatic copolyester further comprising at least an aromatic hydroxycarboxylic acid as a constituent component.

[0036] At least one aromatic copolyester (P) is preferably a liquid crystal polymer (LCP).

[0037] In some embodiments, aromatic polyols are given by the following formula: HO-Ar1-OH(1), and HO-Ar2-T1-Ar3-OH(2) (wherein, Ar1 to Ar3 are independently selected from aryl groups optionally substituted with one or more substituents selected from the group consisting of halogen, C1-C 15 alkyl, and C6-C 15 aryl; T1 is selected from the group consisting of a bond, O, S, -SO2-, -C(=O)-, and C1-C 30 alkyl). 15 )(selected from the group consisting of) is represented by a formula selected from the group of In some embodiments, the aromatic diol is preferably selected from the group consisting of 1,3-dihydroxybenzene, 1,4-dihydroxybenzene, 2,5-biphenyldiol, 4,4'-biphenol, 4,4'-(propan-2,2-diyl)diphenol, 4,4'-(ethane-1,2-diyl)diphenol, 4,4'-methylenediphenol, bis(4-hydroxyphenyl)methanone, 4,4'-oxydiphenol, 4,4'-sulfonyldiphenol, 4,4'-thiodiphenol, naphthalene-2,6-diol, and naphthalene-1,5-diol. Preferably, the aromatic diol is 4,4'-biphenol.

[0038] In some embodiments, at least one aromatic dicarboxylic acid is of the following formula: HOOC-Ar1-COOH(3), and HOOC-Ar2-T2-Ar3-COOH(4) (wherein, Ar1 to Ar3 are as defined above and are independently selected; T2 is selected from the group consisting of a bond, O and S). is independently represented by a formula selected from the group of

[0039] In some embodiments, at least one aromatic dicarboxylic acid is selected from the group consisting of terephthalic acid, 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.

[0040] Preferably, at least one aromatic dicarboxylic acid is selected from the group consisting of terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, and naphthalene-2,3-dicarboxylic acid.

[0041] More preferably, at least one aromatic dicarboxylic acid is terephthalic acid or isophthalic acid.

[0042] More preferably, the aromatic copolyester (P) is a reaction product of at least one aromatic polyol as defined above with terephthalic acid and isophthalic acid.

[0043] In some embodiments, aromatic hydroxycarboxylic acids are HO-Ar1-COOH(5), and HO-Ar2-Ar3-COOH(6) (In the formula, Ar1 to Ar3 are given above and can be selected independently.) It can be expressed by an expression selected from the group consisting of the following:

[0044] 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.

[0045] 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 and 6-hydroxy-2-naphthoic acid.

[0046] In some embodiments, the aromatic copolyester (P) formed by the reaction of the aforementioned monomers is a repeating unit R LCP1 ~R LCP4 It has.

[0047] Repeating unit R LCP1 The formula is as follows: [ka] It is represented by; Repeating unit R LCP2 The formula is as follows: -[-O-Ar1-O-]-(8), and -[-O-Ar2-T1-Ar3-O-]-(9) It is represented by one of the following: Repeating unit R LCP3 The formula is as follows: -[-OC-Ar1-CO-]-(10), and -[-OC-Ar2-T2-Ar3-CO-]-(11) It is represented by one of the following: Repeating unit R LCP4 The formula is as follows: -[-O-Ar1-CO-]-(12), and -[-O-Ar2-Ar3-CO-]-(13) It is represented by one of the following: In the formula, Ar1 to Ar3, T1 and T2 are given above and are selected independently.

[0048] A person skilled in the art would know R according to formula (7). LCP1 It is formed from terephthalic acid; formula R according to (8) and (9) LCP2 However, they are formed from monomers according to formulas (1) and (2), respectively; and R according to formulas (10) and (11). LCP3 However, they are formed from monomers according to formulas (3) and (4), respectively; and R according to formulas (12) and (13). LCP4 However, it will be acknowledged that they are formed from monomers according to formulas (5) and (6).

[0049] Therefore, the selection of Ar1 to Ar3, T1 and T2 for the monomers in equations (1) to (6) is also the repeating unit R LCP2 ~R LCP4 Select Ar1 to Ar3, T1 and T2 for the following. Preferably, the repeating unit R LCP1 ~R LCP4 These are formed from the polycondensation of terephthalic acid, 4,4'-biphenol, isophthalic acid, and 4-hydroxybenzoic acid, respectively.

[0050] In some embodiments, the repeating unit R LCP1 ~R LCP4The total concentration 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%.

[0051] In some embodiments, the concentration of at least one aromatic dicarboxylic acid is 1 mol% to 20 mol%, preferably 1 mol% to 10 mol%.

[0052] In some embodiments, the concentration of aromatic hydroxycarboxylic acid is 35 mol% to 80 mol%, preferably 45 mol% to 75 mol%, and most preferably 50 mol% to 70 mol%.

[0053] In one embodiment, R LCP1 ~R LCP4 These are derived from terephthalic acid, 4,4'-biphenol, isophthalic acid, and 4-hydroxybenzoic acid, respectively, where the concentration range for each repeating unit is within the range given above.

[0054] In another embodiment, R LCP1 ~R LCP4 These are derived from terephthalic acid, 4,4'-biphenol, isophthalic acid, and 6-hydroxy-2-naphthoic acid, respectively, where the concentration range for each repeating unit is within the range given above.

[0055] In this specification, mol% refers to the total number of repeating units in the polymer, unless otherwise explicitly stated.

[0056] To clarify, "derived from" refers to repeating units formed from the polycondensation of the listed monomers, for example, as described above regarding the relationship between formulas 1-6 and 8-13.

[0057] In a preferred embodiment of the present invention, the aromatic copolyester (P) is a reaction product of at least one aromatic polyol, terephthalic acid, isophthalic acid, and 4-hydroxybenzoic acid.

[0058] In some embodiments, the aromatic copolyester (P) has a Tm of at least 220°C, at least 250°C, or at least 280°C.

[0059] In some embodiments, the aromatic copolyester (P) has a Tm of 420°C or less, 390°C or less, or 360°C or less.

[0060] In some embodiments, the aromatic copolyester (P) has a Tm of 220°C to 420°C, 250°C to 390°C, or 280°C to 360°C.

[0061] In some embodiments, the aromatic copolyester (P) has a number-average molecular weight ("Mn") of at least 5,000 g / mol.

[0062] In some embodiments, the aromatic copolyester (P) has a Mn content of 20,000 g / mol or less.

[0063] In some embodiments, the aromatic copolyester (P) has Mn in a range of 5,000 g / mol to 20,000 g / mol.

[0064] The number-average molecular weight Mn can be measured according to ASTM D5296 and by gel permeation chromatography (GPC) using hexafluoroisopropanol solvent and semi-aromatic polyamides of a wide range of molecular weights as a reference standard.

[0065] The aromatic copolyesters (P) described herein can be prepared by any conventional method.

[0066] According to one embodiment, the aromatic copolyester (P) is present in the mixture (M) in an amount of less than 70% by weight, less than 60% by weight, less than 50% by weight, less than 45% by weight, less than 40% by weight, less than 35% by weight, less than 30% by weight, less than 25% by weight, or less than 20% by weight, based on the total weight of the mixture (M).

[0067] According to the present invention, "polyester polymer (PE)" is - At least one dicarboxylic acid component, - At least one diol component [where at least 2 mol% of the diol component is given by formula (I): H(OC m H 2m ) n -OH (In the formula, m is an integer between 2 and 4, and n varies between 2 and 10.) It is a poly(alkylene glycol). This refers to any water-soluble or water-dispersible polymer containing units of origin.

[0068] According to one embodiment, the dicarboxylic acid component of the polyester polymer (PE) includes, for example, at least one aromatic dicarboxylic acid selected from the group consisting of isophthalic acid (IPA), terephthalic acid (TPA), naphthalenedicarboxylic acid (e.g., naphthalene-2,6-dicarboxylic acid), 4,4'-dibenzoic acid, 2,5-pyridinedicarboxylic acid, 2,4-pyridinedicarboxylic acid, 3,5-pyridinedicarboxylic acid, 2,2-bis(4-carboxyphenyl)propane, bis(4-carboxyphenyl)methane, 2,2-bis(4-carboxyphenyl)hexafluoropropane, 2,2-bis(4-carboxyphenyl)ketone, 4,4'-bis(4-carboxyphenyl)sulfone, 2,2-bis(3-carboxyphenyl)propane, bis(3-carboxyphenyl)methane, 2,2-bis(3-carboxyphenyl)hexafluoropropane, 2,2-bis(3-carboxyphenyl)ketone, bis(3-carboxyphenoxy)benzene, and mixtures thereof.

[0069] According to one embodiment, the diol component is such that at least 2 mol% of the diol component is derived from formula (II): H(O-CH2-CH2) n -OH (n varies from 2 to 10) It is similar to poly(ethylene glycol).

[0070] According to one embodiment, the diol component is at least 4 mol%, at least 10 mol%, at least 20 mol%, at least 30 mol%, at least 40 mol%, or at least 50 mol% (based on the total number of moles of the diol component) of formula (I): H(OC m H 2m ) n -OH (m is an integer between 2 and 4, and n varies between 2 and 10) A poly(alkylene glycol), preferably of formula (II): H(O-CH2-CH2) n -OH (n varies from 2 to 10) It is similar to poly(ethylene glycol).

[0071] According to another embodiment, the diol component is such that at least 2 mol%, at least 4 mol%, at least 10 mol%, at least 20 mol%, at least 30 mol%, at least 40 mol%, or at least 50 mol% (based on the total number of moles of the diol component) of the diethylene glycol of the formula HO-CH2-CH2-O-CH2-CH2-OH.

[0072] In further embodiments, apart from a minimum content of 2 mol% poly(alkylene glycol), the diol component may include at least one diol selected from the group consisting of ethylene glycol, 1,4-cyclohexanedimethanol, propane-1,2-diol, 2,2-dimethyl-1,3-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol, isosorbide, and 2,5-bishydroxymethyltetrahydrofuran.

[0073] Furthermore, according to another embodiment, the diol component of the polyester polymer (PE) is essentially, - Diols selected from the group consisting of ethylene glycol, 1,4-cyclohexanedimethanol, propane-1,2-diol, 2,2-dimethyl-1,3-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol, isosorbide, and 2,5-bishydroxymethyltetrahydrofuran. - Equation (II) for at least 2 mol%: H(O-CH2-CH2) n ,-OH (n varies between 2 and 10) Poly(ethylene glycol) It exists in [location].

[0074] According to another embodiment, the diol component of the polyester polymer (PE) is essentially, - Diols selected from the group consisting of ethylene glycol, 1,4-cyclohexanedimethanol, propane-1,2-diol, 2,2-dimethyl-1,3-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol, isosorbide, and 2,5-bishydroxymethyltetrahydrofuran. - At least 2 mol% diethylene glycol (based on the total number of diol components) It exists in [location].

[0075] According to the present invention, a preferred polyester (PE) is a polyester further comprising repeating units derived from a difunctional monomer containing at least one SO3M group bonded to an aromatic nucleus, where the functional group is carboxyl, and M is H or a metal ion selected from the group consisting of sodium, potassium, calcium, lithium, magnesium, silver, aluminum, zinc, nickel, copper, palladium, iron, and cesium, preferably from the group consisting of sodium, lithium, and potassium. Such a preferred polyester may also be called a sulfopolyester (SPE). According to this embodiment, the difunctional sulfomonomer can be present in the SPE in a molar ratio of 1 to 40 mol%, for example, 5 to 35 mol%, or 8 to 30 mol%, based on the total number of moles in the SPE (i.e., the total number of moles of diacid and diol components if the SPE consists exclusively of diacid and diol components).

[0076] According to one embodiment of the present invention, polyester (PE) is - At least one dicarboxylic acid component, - At least one diol component [where at least 2 mol% of the diol component is given by formula (I): H(OC m H 2m ) n -OH (In the formula, m is an integer between 2 and 4, and n varies between 2 and 10.) It is a poly(alkylene glycol) - At least one bifunctional monomer containing at least one SO3M group bonded to an aromatic nucleus (where the functional group is carboxyl, and M is H or a metal ion selected from the group consisting of sodium, lithium, and potassium). Includes the units of origin.

[0077] According to another embodiment of the present invention, polyester (PE) is - At least one aromatic dicarboxylic acid component, - At least one diol component, - At least 1 mol% (based on the total number of unit moles in PE, for example, the total number of moles of diacid and diol components if PE is composed solely of units of diacid and diol), of formula (I): H(OC m H 2m ) n -OH (In the formula, m is an integer between 2 and 4, and n varies between 2 and 10, preferably m is equal to 2 and n is equal to 2.) Poly(alkylene glycol), - At least one aromatic dicarboxylic acid containing at least one SO3M group bonded to an aromatic nucleus (where M is H or a metal ion selected from the group consisting of sodium, lithium, and potassium). Includes the units of origin.

[0078] According to a preferred embodiment of the present invention, polyester (PE) is - Aromatic dicarboxylic acids selected from the group consisting of isophthalic acid (IPA), terephthalic acid (TPA), naphthalenedicarboxylic acid (e.g., naphthalene-2,6-dicarboxylic acid), 4,4'-dibenzoic acid, 2,5-pyridinedicarboxylic acid, 2,4-pyridinedicarboxylic acid, 3,5-pyridinedicarboxylic acid, 2,2-bis(4-carboxyphenyl)propane, bis(4-carboxyphenyl)methane, 2,2-bis(4-carboxyphenyl)hexafluoropropane, 2,2-bis(4-carboxyphenyl)ketone, 4,4'-bis(4-carboxyphenyl)sulfone, 2,2-bis(3-carboxyphenyl)propane, bis(3-carboxyphenyl)methane, 2,2-bis(3-carboxyphenyl)hexafluoropropane, 2,2-bis(3-carboxyphenyl)ketone, bis(3-carboxyphenoxy)benzene and mixtures thereof, preferably isophthalic acid. - Diols selected from the group consisting of ethylene glycol, 1,4-cyclohexanedimethanol, propane-1,2-diol, 2,2-dimethyl-1,3-propanediol, and mixtures thereof, - At least 1 mol% (total number of unit moles in PE, for example, based on the total number of dioxide and diol components if PE is composed solely of dioxide and diol units) of diethylene glycol, - Aromatic dicarboxylic acids containing at least one SO3M group bonded to an aromatic nucleus (e.g., isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid) (where M is H or a metal ion selected from the group consisting of sodium, lithium, and potassium). It contains or is essentially present in the units from which it originates.

[0079] According to one embodiment, the PE contains at least 2 mol%, at least 4 mol%, at least 10 mol%, at least 20 mol%, at least 30 mol%, at least 40 mol%, or at least 50 mol% of diethylene glycol, based on the total number of unit moles in the PE (for example, the total number of diacid and diol components if the PE is composed solely of diacid and diol units).

[0080] Examples of such polyesters include Eastman AQ Polymers, particularly those having a glass transition temperature in the range of about 25°C to about 50°C. Eastman AQ 38S, a polyester composed of diethylene glycol, cyclohexanedimethanol / (CHDM), isophthalate, and sulfoisophthalate units, is most preferred.

[0081] The polyester (PE) of the present invention is in the form of a salt of a sulfonic acid or / or carboxylic acid, more precisely, sulfonate-SO3 - , or carboxylate-COO - It can take the form of PE, therefore, one or more groups (SO3 - M + ) and / or (COO - M +) (wherein M is a metal) may include. According to one embodiment, M is selected from the group consisting of sodium, potassium or lithium, calcium, magnesium, silver, aluminum, zinc, nickel, copper, palladium, iron and cesium.

[0082] The polyester (PE) of the present invention can be derived, for example, by esterification of the described components.

[0083] The number-average molecular weight of polyester (PE), as measured by GPC, can range from 1,000 g / mol to 40,000 g / mol, more preferably from 2,000 g / mol to 30,000 g / mol.

[0084] According to one embodiment, the polyester (PE) polymer is present in the mixture (M) in an amount of at least 30% by weight, at least 35% by weight, at least 40% by weight, at least 45% by weight, at least 50% by weight, at least 55% by weight, at least 60% by weight, at least 65% by weight, at least 70% by weight, at least 75% by weight, or at least 80% by weight, based on the total weight of the mixture (M).

[0085] According to a preferred embodiment, the mixture (M) is a) 20-60% by weight of aromatic copolyester (P), b) 40-80% by weight of polyester (PE) and Includes.

[0086] The applicant has unexpectedly discovered that the method of the present invention makes it possible to easily obtain fine particles of aromatic copolyester (P) characterized by low cost, small amounts of impurities, and orderly shape and size.

[0087] As used herein, the term "particle" refers to an individualized entity.

[0088] The term "fine particles" refers to particles having a particle size distribution D50 (abbreviated as "D50") of approximately 0.1 μm to 100 μm, where D50 is also known as the median diameter or median value of the particle size distribution. In this specification, this means that 50% of the particles in the sample are larger than D50, and 50% are smaller than D50. Particle size analysis is performed, for example, using a Microtrac Sample Delivery Controller (SDC). TM This can be done with S3500.

[0089] The D50 of the aromatic copolyester (P) fine particles is preferably 0.5 μm to 50 μm, more preferably 1 μm to 25 μm, and even more preferably 1 μm to 10 μm.

[0090] The particles of the present invention have a roundness and / or curvature of, for example, at least 0.75, for example, at least 0.8 or at least 0.85, and are preferably substantially spherical.

[0091] Roundness is defined as a measure of the surface smoothness of a particle, and is given by the following equation:

number

[0092] Roundness is defined as a measure of the sphericalness of a particle, and is given by the following equation:

number

[0093] The aromatic copolyester (P) fine particles obtained by the method of the present invention preferably substantially contain impurities, and in particular substantially do not contain residual polyester (PE).

[0094] The content of residual polyester (PE) component in aromatic copolyester (P) fine particles can be evaluated by thermogravimetric analysis.

[0095] The term "preferably free of residual polyester (PE)" means that the content of residual polyester (PE) in aromatic polyester (P) fine particles is preferably less than 0.1% by weight, more preferably less than 0.05% by weight, and even more preferably 0.01% by weight or less.

[0096] The applicant has unexpectedly found that the method of the present invention makes it possible to easily obtain fine particles of aromatic copolyester (P) starting from larger particle size aromatic polyester with a very limited reduction in its melt viscosity, of 30% or less compared to the melt viscosity of the particles before the process of converting the particles to fine particles.

[0097] The particles of the present invention can be characterized by their bulk density and their tap density. The bulk density of a powder is the ratio of the mass of an untapped powder sample to its volume, including the contribution of interparticle void volume. Bulk density is expressed in grams per milliliter (g / ml) or grams per cubic centimeter (g / cm³). 3 It can be expressed in units of ). Density measurement is, for example, Quantachrome Autotap TM This can be done using a Tapped Density analyzer.

[0098] The aromatic copolyester (P) particles obtained by the above method can also be processed in the following possible steps: - A step of drying at a temperature of at least 80°C, for example at least 90°C, for at least 0.5 hours, preferably at least 1 hour, optionally under reduced pressure; and - The process of sieving It can be multiplied by at least one of the following.

[0099] In another embodiment, the present invention provides fine particles of aromatic copolyester (P) obtained by the method defined above.

[0100] The fine particles of the aromatic copolymer (P) of the present invention can be used in a variety of applications, particularly as an additive in varnish formulations such as polyimides, polyimide precursors, or epoxy resins for producing coatings and films with low target thicknesses in the range of 5 to 100 microns.

[0101] The present invention will be described in more detail below in relation to the following embodiments, but the purpose is merely illustrative and not to limit the scope of the invention. [Examples]

[0102] raw materials PE: Eastman AQ, a sulfopolyester sold commercially by Eastman. TM 48. This PE is composed of diethylene glycol, cyclohexanedimethanol (CHDM), isophthalate, and sulfoisophthalate units. According to 1H NMR analysis, the molar concentration of diethylene glycol is 70 mol%, based on the total moles of the diol (CHDM + diethylene glycol).

[0103] PCT: Poly(cyclohexylenedimethylene terephthalate), commercially available from Eastman.

[0104] Preparation Example 1: Synthesis of LCP To synthesize LCP, the 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 charged 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 under reflux conditions for 1 hour. Heating was then continued to 300°C at a rate of 0.5°C / min while acetic acid was distilled off from the reactor. The prepolymer was discharged and allowed to cool. The material was then ground into a powder for solid-phase polymerization. The resin was advanced in a rotary oven under the following profile: continuous nitrogen purging at 220°C for 1 hour, 290°C for 1 hour, and 310°C for 12 hours. The resulting high molecular weight resin had a melt viscosity of 500-1500 poise at 370°C and a shear rate of 100 / s.

[0105] Material The mixture was prepared according to Table 1. Each composition was melt-blended in a ZSK26 twin-screw extruder at a temperature in the range of 330–360°C and at 100–200 rpm. Each mixture was then processed into strands and rapidly cooled in air until solidified. The samples were immersed in water heated to 95°C for 2 hours. The water was then removed. The samples were again immersed in water heated to 90°C for 2 hours.

[0106] Several compositions (Examples 1 and 2) yielded polymer powders according to the present invention. The powders were then isolated by filtration, washed with water, and vacuum-dried.

[0107] [Table 1]

[0108] Scanning electron microscopy (SEM) As shown below, each polymer sample was examined using scanning electron microscopy. The powder was dispersed on carbon tape fixed to an aluminum stub, and then sputter-coated with AuPd using an Emitech K575x Turbo Sputter Coater. Images were recorded using a Hitachi S-4300 Cold Field Emission Scanning Electron Microscope, and the average diameter of 50 approximate particle images was analyzed using ImageJ v 1.49b Java-Based Image Analysis Software. A summary of the average particle diameters estimated from the SEM images of the powders is shown in Table 2.

[0109] Figure 1 shows an SEM scan of LCP starting particles, Figures 2 and 3 show SEM scans of LCP particles from Examples 1 and 2, and Figures 4 and 5 show SEM scans of PCT particles from Comparative Examples 3 and 4. The powder according to the present invention has a more homogeneous spherical shape, while those obtained by processing PCT have disc-like and more elongated particle shapes.

[0110] [Table 2]

[0111] Intrinsic melt viscosity measurement The powder was dried at 150°C for 10 minutes and at 120°C for 5 minutes before measuring the melt viscosity. The melt viscosity at a shear rate of 100 / s was measured using a capillary rheometer (Dynisco LCR 7000, die L / D=20) set to the test temperatures shown in Table 3.

[0112] The results are shown in Table 3.

[0113] Density measurement Density measurement is performed using Quantachrome Autotap. TMThe analysis was performed using a Tapped Density analyzer. The results are shown in Table 3.

[0114] Residual PE in fine particles The amount of residual PE in the powder was calculated by thermogravimetric analysis in a temperature scanning mode (30-800°C) under a nitrogen atmosphere. The results are shown in Table 3.

[0115] [Table 3]

[0116] The results demonstrate that the fine particles of the aromatic copolyester of the present invention exhibit high purity, as expressed in terms of residual PE, while the same method applied to semi-aromatic polyesters still results in particles containing residual PE in their powders.

[0117] Surprisingly, it was discovered that LCP particles obtained by this method, unlike semi-aromatic PCT particles, have a diameter of less than 20 microns, are spherical, and retain their initial melt viscosity well.

[0118] Furthermore, the PCT particles of Comparative Examples 3 and 4 showed a significant loss of their melt viscosity after processing, meaning that the performance of the PCT particles deteriorated considerably. Surprisingly, the LCP particles of Examples 1 and 2 were observed to maintain their high melt viscosity very well after processing, meaning that they did not show any significant loss of their performance.

[0119] If any disclosure of a patent, patent application, or publication incorporated herein by reference conflicts with the description of this application to such an extent that it could obscure the terminology, the description herein shall prevail.

Claims

1. A method for preparing fine particles of a total aromatic copolyester (P), comprising the following steps: a) i) At least one all-aromatic copolyester (P), ii) - At least one dicarboxylic acid component, - At least one diol component [where at least 2 mol% of the diol component is of formula (I): H(O-C ｍ H ２ｍ ) ｎ -OH (In the formula, m is an integer between 2 and 4, and n varies between 2 and 10.) It is a poly(alkylene glycol) having [the properties of] A polyester polymer (PE) containing units derived from and A step of melt-blending a mixture (M) containing the following: b) A step of processing the mixture (M) obtained in step a) into pellets or strands, c) Optionally, a step of cooling the pellet or strand obtained in step b) at a temperature of less than 80°C, d) A step of bringing the pellets or strands obtained in step b) or c) into contact with water to obtain fine polymer particles of at least one type of fully aromatic copolyester (P), e) A step of recovering fine polymer particles of at least one type of total aromatic copolyester (P), f) Optionally, a step of drying the particles recovered in step e), g) optionally a step of sieving the particles obtained in step e) or step f) Includes, The at least one polyester polymer (PE) is water-soluble or water-dispersible. The polyester polymer (PE) has at least one SO bonded to the aromatic nucleus. ３ A method comprising a bifunctional monomer containing an M group, further comprising repeating units derived from the bifunctional monomer in which the functional group is carboxyl and M is H or a metal ion selected from the group consisting of sodium, lithium and potassium, wherein the content of the polyester polymer (PE) in the fine particles of the total aromatic copolyester (P) is less than 0.1% by weight.

2. The aforementioned polyester polymer (PE) - At least one aromatic dicarboxylic acid component, - At least one diol component, - Formula (I) of at least 1 mol% (based on the total number of moles in the polyester polymer (PE)): H(O-C ｍ H ２ｍ ) ｎ -OH (In the formula, m is an integer between 2 and 4, and n varies between 2 and 10.) Poly(alkylene glycol), - At least one SO bonded to the aromatic nucleus ３ An aromatic dicarboxylic acid containing an M group, wherein M is H or a metal ion selected from the group consisting of sodium, lithium, and potassium. The method according to claim 1, including the derived unit.

3. The aforementioned polyester polymer (PE) - Isophthalic acid, - Diols selected from the group consisting of ethylene glycol, 1,4-cyclohexanedimethanol, propane-1,2-diol, 2,2-dimethyl-1,3-propanediol, and mixtures thereof, - At least 2 mol% (based on the total number of moles in the PE) of diethylene glycol poly(alkylene glycol), - at least one SO bonded to an aromatic nucleus ３ An aromatic dicarboxylic acid containing an M group, wherein M is H or a metal ion selected from the group consisting of sodium, lithium, and potassium The method according to claim 1 or 2, comprising or presenting in units of origin.

4. The method according to any one of claims 1 to 3, wherein the all-aromatic copolyester (P) is an all-aromatic polyester which is a reaction product of at least one aromatic polyol, at least one aromatic dicarboxylic acid, and at least one aromatic hydroxycarboxylic acid.

5. The method according to any one of claims 1 to 4, wherein the all-aromatic copolyester (P) is a liquid crystal polymer (LCP).

6. The method according to any one of claims 1 to 5, wherein the all-aromatic copolyester (P) is a reaction product of at least one aromatic polyol, terephthalic acid, isophthalic acid, and 4-hydroxybenzoic acid.

7. The method according to any one of claims 1 to 6, wherein the total aromatic copolyester (P) is a reaction product of at least one aromatic polyol, terephthalic acid, and 6-hydroxy-2-naphthoic acid.

8. The mixture (M) is a) 20-60% by weight of all aromatic copolyester (P), b) 40-80% by weight of polyester polymer (PE) and The method according to any one of claims 1 to 7, including the method described in any one of claims 1 to 7.

9. The method according to any one of claims 1 to 8, wherein the melt-blending step is performed at a temperature exceeding 300°C.

10. The method according to any one of claims 1 to 9, wherein the particles have D50 contained in a size of 0.5 μm to 50 μm.

11. Use of fine particles of a total aromatic copolyester (P) obtained by the method of any one of claims 1 to 10 as an additive in varnish formulations for manufacturing coatings and films.

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