Liquid crystal polyester resin composition, and molded article and electronic component material comprising same

Abstract

The present invention relates to a liquid crystal polyester resin composition, and a molded article and an electronic component material comprising the same, and more specifically, to a liquid crystal polyester resin composition, the present invention relates to a liquid crystal polyester resin composition, and more particularly, to a liquid crystal polyester resin composition having good weld line impact strength and dust generation resistance, and to a molded article and an electronic component material comprising the same.

Description

Technical Field

[0001] Embodiments of the present invention relate to a liquid crystal polyester resin composition, a molded article, and an electronic component material including the liquid crystal polyester resin composition, and more particularly, to a liquid crystal polyester resin composition having good weld line impact strength and resistant to dust generation, and a molded article and an electronic component material including the liquid crystal polyester resin composition. Background Art

[0002] Liquid crystal polyester resins refer to molten polyester resins in which the molecular chains in the polymer are aligned in a highly ordered and parallel manner. This ordered arrangement of molecules is often referred to as the liquid crystalline phase or nematic phase of the liquid crystal. These polymer molecules are typically long, thin, and flat, thus providing superior mechanical strength, electrical properties, and heat resistance along the long chains of the molecules.

[0003] Compositions based on liquid crystal polyester resins offer excellent heat resistance and high fluidity, making them ideal for a wide range of electrical / electronic applications. As small portable devices such as laptop computers become thinner, lighter, and more powerful, the demand for liquid crystal polyester resin compositions with good moldability is increasing day by day.

[0004] However, liquid crystal polyester resin compositions are characterized in that the molten polymer does not lose its crystal structure during flow. Therefore, during the molding process, when the resin composition is injection molded into a product with a complex shape, weld lines are formed at the interfaces where the resin flows meet. These weld lines are very fragile, making the molded article vulnerable to damage caused by internal / external impacts or friction.

[0005] In addition, molded articles made from liquid crystal polyester resin compositions are prone to fibrillization, which is a phenomenon in which the surface of the molded article peels off due to ultrasonic cleaning or friction with other components, thereby forming fibrils. When these molded articles are used as electronic components of electronic products, foreign substances (e.g., dust or fibrils) detached from the fibrillized areas can greatly damage the performance of the electronic products.

[0006] For example, in the case of electronic components, particularly optical devices having lenses, particulate contaminants such as dirt and dust adhering to the lenses can seriously damage the optical properties of the optical devices. Fibrillation can occur during the assembly or operation of the camera module. Specifically, when the autofocus function of the camera is activated, dust particles can be generated from the surface of the components due to the sliding of the components of the camera module. Dust particles can also be generated when the device is impacted or dropped. With the recent trend towards miniaturization of peripheral devices and accessories used in electronic products, there is an increasing demand for electronic component materials that are highly resistant to dust generation and can thus be used as materials for dust-sensitive semiconductors and optical components.

[0007] In this regard, Korean Patent Laid-Open Publication No. 10-2014-0007792 discloses a liquid crystal polyester resin composition designed to obtain a molded article having a high resistance to fibrillation. Summary of the Invention

[0008] Embodiments of the present invention provide a liquid crystal polyester composition and an electronic component material comprising the liquid crystal polyester composition, the liquid crystal polyester composition being resistant to physical damage caused by internal / external friction and internal / external impact, having improved impact strength and weld line impact strength, and minimizing dust generation and fibril formation.

[0009] According to one aspect of the present invention, there is provided a liquid crystal polyester resin composition comprising: a liquid crystal polyester resin; a fibril inhibitor; an esterification inhibitor; and a filler.

[0010] Preferably, the fibril inhibitor comprises a compound including repeating units derived from an α-olefin and repeating units derived from an α,β-unsaturated carboxylic acid or its ester.

[0011] Preferably, the fibril inhibitor comprises at least one selected from the group consisting of ethylene-(meth)acrylic acid copolymer, ethylene-methyl(meth)acrylic acid copolymer, ethylene-ethyl(meth)acrylic acid copolymer, and ethylene-butyl(meth)acrylic acid copolymer.

[0012] Preferably, the esterification inhibitor comprises a phosphite compound.

[0013] Preferably, the filler includes a carbon-based filler and an inorganic filler.

[0014] Preferably, the liquid crystal polyester resin composition comprises: 55% to 85% by weight of a liquid crystal polyester resin; 2% to 8% by weight of a fibril inhibitor; 0.1% to 1.0% by weight of an esterification inhibitor; 1% to 5% by weight of a carbon-based filler; and 10% to 30% by weight of an inorganic filler.

[0015] Preferably, the carbon-based filler comprises at least one selected from the group consisting of carbon black, graphite, and carbon nanotubes.

[0016] Preferably, the inorganic filler comprises at least one selected from the group consisting of: serpentine, montmorillonite, talc, mica, chlorite, glass flakes, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, clay, siliceous earth, wollastonite, iron oxide, titanium oxide, zinc oxide, aluminum oxide, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, silicon carbide, silicon nitride, boron nitride, and potassium titanate.

[0017] Preferably, the liquid crystal polyester resin composition further comprises: a lubricant.

[0018] Preferably, the molded article formed from the liquid crystal polyester resin composition has a weld line impact strength greater than 20 J / m.

[0019] Preferably, the molded article formed from the liquid crystal polyester resin composition has a dent depth less than 21 μm.

[0020] Preferably, the molded article formed from the liquid crystal polyester resin composition has a dent volume less than 11,000,000 μm 3 .

[0021] According to another aspect of the present invention, there is provided a molded article, which is manufactured from the above liquid crystal polyester resin composition.

[0022] According to still another aspect of the present invention, there is provided an electronic component material, which comprises the above liquid crystal polyester resin composition.

[0023] The liquid crystal polyester resin composition according to the present invention can minimize dust generation caused by internal / external impact or friction without sacrificing the inherent properties of the liquid crystal polyester resin, such as good mechanical properties, thermal properties, electrical properties, and good flame retardancy.

[0024] The liquid crystal polyester resin composition according to the present invention, the molded article comprising the liquid crystal polyester resin composition, and the electronic component material have good properties in terms of impact strength and weld line impact strength, and resist dust generation and fibril formation caused by internal / external friction or impact.

[0025] In addition, the liquid crystal polyester resin composition according to the present invention, and molded articles and electronic component materials containing the liquid crystal polyester resin composition, can be used as materials for components of electronic products that are sensitive to internal / external impacts and internal / external friction because they are resistant to dust generation / fibril formation and have good weld line impact strength. Specifically, when used as a material for components of a camera module, particularly a camera module of a mobile phone, the liquid crystal polyester resin composition according to the present invention can contribute to maintaining or improving optical properties such as pixel count and image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] None DETAILED DESCRIPTION

[0027] Hereinafter, various exemplary embodiments of the present invention will be described.

[0028] Unless otherwise specified, technical and scientific terms used herein have the meanings commonly understood by those skilled in the art. It should also be understood that terms (e.g., terms defined in common dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the specification and the relevant art, and should not be interpreted as idealized or overly formal meanings unless explicitly defined herein.

[0029] In addition, it should be understood that when the term "includes / comprises / including and / or comprising" is used in this specification, it specifies the presence of the stated element, but does not exclude the presence or addition of one or more other elements.

[0030] According to one aspect of the present invention, a liquid crystal polyester resin composition may include a liquid crystal polyester resin, a fibril inhibitor, an esterification inhibitor, and a filler.

[0031] The liquid crystal polyester resin exhibits liquid crystallinity when melted, and preferably melts at a temperature of 450 °C or lower.

[0032] Considering the mechanical strength and injection moldability of the liquid crystal polyester resin, the liquid crystal polyester resin may have a weight-average molecular weight of from about 10,000 g / mol to 300,000 g / mol, preferably from about 10,000 g / mol to 50,000 g / mol. If the weight-average molecular weight of the liquid crystal polyester resin is less than 10,000 g / mol, the liquid crystal polyester resin composition may have poor mechanical strength, making the molded article made from the liquid crystal polyester resin composition liable to damage. If the weight-average molecular weight of the liquid crystal polyester resin exceeds 300,000 g / mol, the liquid crystal polyester resin composition may have poor fluidity and thus poor injection moldability.

[0033] Based on the total weight of the liquid crystal polyester resin composition, the liquid crystal polyester resin may be present in an amount of from about 55 wt% to about 85 wt%, preferably from about 60 wt% to about 80 wt%, more preferably from about 65 wt% to about 80 wt%. If the content of the liquid crystal polyester resin is less than about 55 wt%, the resin composition may have poor fluidity, making micro-injection molding of the resin composition difficult. If the content of the liquid crystal polyester resin component exceeds about 85 wt%, the resin composition may have excessive fluidity, deteriorating the strength and heat resistance of the molded article or electronic component made from the resin composition.

[0034] The liquid crystal polyester resin may comprise at least one selected from the group consisting of liquid crystal polyester amide, liquid crystal polyester ether, liquid crystal polyester carbonate, and liquid crystal polyester imide.

[0035] Preferably, the liquid crystal polyester resin comprises an all-aromatic liquid crystal polyester prepared using only aromatic compounds as monomer materials. Typical examples of the all-aromatic liquid crystal polyester include: resins prepared by polymerization (polycondensation) of at least one compound selected from the group consisting of aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, aromatic diols, aromatic hydroxyamines, and aromatic diamines; resins prepared by polymerization of two or more aromatic hydroxycarboxylic acids; resins prepared by polymerization of one or more compounds selected from the group consisting of aromatic dicarboxylic acids, aromatic diols, aromatic hydroxyamines, and aromatic diamines; and resins prepared by polymerization of a polyester (e.g., polyethylene terephthalate) and an aromatic hydroxycarboxylic acid.

[0036] The liquid crystal polyester resin can be prepared by forming a liquid crystal polyester prepolymer by polycondensation of one or more aromatic monomers and then subjecting the prepolymer to solid-phase polycondensation. Removal of the by-products of the solid-phase polycondensation process can be achieved by purging or evacuating with an inert gas.

[0037] The liquid crystal polyester resin used in the resin composition according to the present invention can be prepared by polymerizing one or more monomers selected from the group consisting of, for example, hydroxybenzoic acid (HBA), hydroxynaphthoic acid (HNA), biphenol (BP), terephthalic acid (TPA), and acetaminophen (APAP).

[0038] For example, the liquid crystal polyester resin can be prepared by polymerizing a monomer mixture containing 56 mol% to 66 mol% of hydroxybenzoic acid (HBA), 2 mol% to 8 mol% of hydroxynaphthoic acid (HNA), 9 mol% to 17 mol% of biphenol (BP), 11 mol% to 21 mol% of terephthalic acid (TPA), and 2 mol% to 8 mol% of acetaminophen (APAP). Within these content ranges of the above monomers, the liquid crystal polyester resin can ensure fluidity, and the resin composition containing the liquid crystal polyester resin can improve the mechanical properties (e.g., impact strength) of the final product while minimizing dust generation and fibril formation.

[0039] The fibril inhibitor according to the present invention can improve the resistance of the liquid crystal polyester resin composition to internal / external impacts while reducing the formation of fibrils. The fibril inhibitor can include a copolymer including repeating units derived from an α-olefin and repeating units derived from an α,β-unsaturated carboxylic acid or its ester.

[0040] The α-olefin can include, for example, C 2 to C 10 α-olefins, such as ethylene, propylene, butene, hexene, octene, etc., especially ethylene. The α,β-unsaturated carboxylic acid or its ester can include, for example, (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, etc., and preferably includes methyl methacrylate.

[0041] As the fibril inhibitor, the copolymer including repeating units derived from an α-olefin and repeating units derived from an α,β-unsaturated carboxylic acid or its ester can include, for example, ethylene-(meth)acrylic acid copolymer, ethylene-methyl (meth)acrylate copolymer, ethylene-ethyl (meth)acrylate copolymer, ethylene-butyl (meth)acrylate copolymer, etc., and preferably includes ethylene-methyl methacrylate copolymer.

[0042] Based on the total weight of the liquid crystal polyester resin composition, the fibril inhibitor may be present in an amount of about 2% by weight to about 8% by weight. If the content of the fibril inhibitor is less than about 2% by weight, the resin composition may have poor impact strength, resulting in an increase in fibril formation after washing of the molded article made from the resin composition. If the content of the fibril inhibitor exceeds about 8% by weight, the fluidity of the resin composition may change due to a decrease in its melt viscosity, making it difficult to obtain a high-quality molded article and causing deterioration of the mechanical properties of the molded article made from the resin composition and an increase in the indentation depth (μm) and indentation volume (μm 3 ) of the molded article, thereby leading to an increase in dust generation.

[0043] The esterification inhibitor can be used to improve or enhance the melt viscosity and weld line impact strength of the liquid crystal polyester resin composition. Since the preparation and processing of the liquid crystal polyester resin composition are carried out at a high temperature of about 300 °C to 400 °C, additives including the esterification inhibitor, etc. need to not decompose at a high temperature of about 300 °C to 400 °C. The esterification inhibitor may include, for example, phosphite compounds, specifically including pentadecyl phosphite, hexadecyl phosphite, heptadecyl phosphite, octadecyl phosphite, nonadecyl phosphite, eicosyl phosphite, etc., and preferably includes at least one selected from the group consisting of heptadecyl phosphite, octadecyl phosphite, and nonadecyl phosphite.

[0044] Based on the total weight of the liquid crystal polyester resin composition, the esterification inhibitor may be present in an amount of about 0.1% by weight to about 1.0% by weight. If the content of the esterification inhibitor is less than about 0.1% by weight, the resin composition may have poor fluidity due to its low melt viscosity, making it difficult to obtain a high-quality molded article, and the molded article made from the resin composition may be easily damaged due to deterioration of its impact strength and weld line impact strength. If the content of the esterification inhibitor exceeds about 1.0% by weight, the indentation depth (μm) and indentation volume (μm 3 ) of the molded article made from the resin composition may increase, and the formation of fibrils on the surface of the molded article cannot be effectively inhibited, thereby leading to problems caused by dust and fibrils.

[0045] The molded article made from the liquid crystal polyester resin composition containing a fibril inhibitor and an esterification inhibitor resists the formation of fibrils on its surface and resists damage caused by internal / external impact or friction due to its good weld line impact strength.

[0046] The filler may include both carbon-based fillers and inorganic fillers.

[0047] The carbon-based filler may include at least one selected from the group consisting of carbon black, graphite, and carbon nanotubes. These carbon-based fillers may be used alone or in combination. Preferably, the carbon-based filler contains carbon black. Based on the total weight of the liquid crystal polyester resin composition, the carbon-based filler may be present in an amount of about 1 wt% to about 5 wt%. For example, carbon black can be used as the carbon-based filler to ensure light-blocking properties. Based on the total weight of the liquid crystal polyester resin composition, carbon black may be present in an amount of about 1 wt% to about 5 wt%. If the content of carbon black is less than about 1 wt%, the blackness of the liquid crystal polyester resin composition may be reduced, making it difficult to ensure sufficient light-blocking properties. If the content of carbon black exceeds about 5 wt%, the carbon black particles may agglomerate rather than being uniformly dispersed in the liquid crystal polyester resin composition, resulting in deterioration of the physical properties of the resin composition and increasing the possibility of the agglomerates falling off as dust.

[0048] Inorganic fillers can be used to improve the mechanical strength, heat resistance, and resistance to impact-induced dents of the resin composition. The mixing of inorganic fillers with the liquid crystal polyester resin needs to be carried out without damaging the mechanical properties (strength, stiffness, hardness, etc.), heat resistance, and electrical properties of the polyester resin. Inorganic fillers can include any non-fibrous fillers, such as flaky fillers, particulate fillers, etc. Based on the total weight of the liquid crystal polyester resin composition, the inorganic filler may be present in an amount of about 10 wt% to about 30 wt%.

[0049] Flaky fillers can be used to improve the mechanical properties and heat resistance of the resin composition and impart dimensional stability to the molded article. Flaky fillers can include serpentine, montmorillonite, talc, mica (biotite, muscovite, phlogopite, etc.), chlorite, glass flakes, etc.

[0050] Particulate fillers can include: silicates, such as silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, clay, siliceous earth, and wollastonite; metal oxides, such as iron oxide, titanium oxide, zinc oxide, and aluminum oxide; metal carbonates, such as calcium carbonate and magnesium carbonate; metal sulfates, such as calcium sulfate and barium sulfate; silicon carbide; silicon nitride; boron nitride; potassium titanate; and so on.

[0051] The inorganic filler may include at least one selected from the above flaky fillers, at least one selected from the above particulate fillers, or a combination thereof.

[0052] The liquid crystal polyester resin composition according to the present invention may further include a lubricant. The lubricant may include, for example, transition metal compounds containing elements belonging to Group VI of the periodic table, particularly molybdenum compounds, tungsten compounds, and chromium compounds.

[0053] The lubricant can enhance the fluidity of the resin composition during high-temperature injection molding and can maximize the alignment of the polymer chains of the liquid crystal polyester resin, thereby improving the flexural strength, flexural modulus, impact strength, and weld line impact strength of the molded article, while minimizing dust generation and fibril formation caused by internal / external impact or friction.

[0054] The lubricant may include transition metal sulfides containing elements belonging to Group VI of the periodic table, particularly at least one selected from the group consisting of: molybdenum disulfide (MoS 2 ), molybdenum diselenide (MoSe 2 ), molybdenum sulfide selenide (MoSSe), and molybdenum trioxide (MoO 3 ), tungsten disulfide (WS 2 ), tungsten diselenide (WSe 2 ), tungsten sulfide selenide (WSSe), tungsten trioxide (MoO 3 ), chromium disulfide (CrS 2 ), chromium diselenide (CrSe 2 ), chromium sulfide selenide (CrSSe), and chromium trioxide (CrO 3 ). Preferably, the lubricant contains molybdenum disulfide (MoS 2 ) or tungsten disulfide (WS 2 ), and more preferably contains molybdenum disulfide (MoS 2 ).

[0055] Transition metal sulfides have a layered structure in which one layer of transition metal is sandwiched between two layers of sulfur, and are characterized in that the layers are prone to slide relative to each other due to the weak van der Waals forces between the layers and have a low coefficient of friction. Among transition metal sulfides, molybdenum disulfide can be added to plastics to obtain a composite material with low frictional resistance and high strength, or can be vacuum deposited on the surface of other materials to obtain a self-lubricating composite material for high-temperature applications.

[0056] Based on the total weight of the liquid crystal polyester resin composition, the lubricant may be present in an amount greater than about 0.5 wt% and less than about 10 wt%, preferably greater than about 0.5 wt% and less than or equal to about 5 wt%, more preferably about 1 wt% to about 5 wt%, and still more preferably about 1 wt% to about 3 wt%.

[0057] If the content of the lubricant is 10 wt% or greater than 10 wt%, the lubricant cannot be properly dispersed in the liquid crystal polyester resin composition, resulting in poor extrusion processability of the resin composition and thus very poor mechanical properties of the molded article. In addition, such poor mechanical properties of the molded article can lead to increased dust generation and increased fibril formation.

[0058] If the content of the lubricant is about 0.5% by weight or less than 0.5% by weight, since the degree of alignment of the polymer chains decreases at a temperature higher than the melting point of the liquid crystal polyester resin, the improvement of the mechanical properties of the molded article cannot be fully achieved, resulting in an increase in dust generation and an increase in fibril formation.

[0059] By using a fibril inhibitor, an esterification inhibitor, and a filler, the liquid crystal polyester resin composition according to the present invention can have improved properties in terms of impact strength and dent resistance, thereby minimizing or suppressing dust generation and fibril formation caused by internal / external impact or friction. In addition, the liquid crystal polyester resin composition according to the present invention can minimize the size of dust particles generated from the molded article and the size of fibrils formed on the surface of the molded article, while ensuring that the molded article has good weld line impact strength. In addition, the liquid crystal polyester resin composition according to the present invention can improve the impact strength of the weld line that appears on a molded article having a complex structure, thereby minimizing or preventing damage to the molded article caused by internal / external impact. Specifically, when used as a material for components of a camera module, the liquid crystal polyester resin composition according to the present invention can significantly contribute to maintaining or improving the optical performance of the camera module, such as the number of pixels and image quality.

[0060] According to another aspect of the present invention, a molded article or an electronic component material can be manufactured from the liquid crystal polyester resin composition containing the foregoing components. The liquid crystal polyester resin composition according to the present invention has improved properties in terms of the alignment of polymer chains, so that the molded article or electronic component material according to the present invention can have good properties in terms of mechanical strength (including weld line impact strength) and minimize dust generation and fibril formation. Specifically, when used as a material for components of a camera module of a mobile device such as a smart phone, the liquid crystal polyester resin composition according to the present invention can contribute to maintaining or improving the optical performance of the camera module, such as the number of pixels and image quality.

[0061] When measured using a melt viscometer after drying the liquid crystal polyester resin composition, the liquid crystal polyester resin composition according to the present invention can have a melt viscosity of 15 Pa·s to 20 Pa·s.

[0062] When measured on a sample prepared using an injection molding machine after drying the liquid crystal polyester resin composition, the liquid crystal polyester resin composition according to the present invention can have an impact strength greater than 80 kJ / m 2 of.

[0063] When measured on a sample prepared using an injection molding machine after drying the liquid crystal polyester resin composition, the liquid crystal polyester resin composition according to the present invention can have a weld line impact strength greater than 20 J / m.

[0064] When measured on a sample using a sink mark simulator, the liquid crystal polyester resin composition according to the present invention may have a sink mark depth of less than 21 μm and a sink mark volume of less than 11,000,000 μm 3 wherein the sample is prepared using an injection molding machine after drying the liquid crystal polyester resin composition.

[0065] Next, the present invention will be described in more detail with reference to some examples. However, it should be noted that these examples are provided for illustrative purposes only and should not be construed as limiting the present invention in any way.

[0066] Preparation Example: Preparation of Liquid Crystal Polyester Resin

[0067] 1. After placing 13,000 g (127.3 mol) of acetic anhydride into a 200 L batch reactor, 20,000 g (144.8 mol) of p-hydroxybenzoic acid (HBA), 2,200 g (11.8 mol) of hydroxynaphthoic acid (HNA), 5,400 g (29.3 mol) of biphenol, 6,500 g (39.6 mol) of terephthalic acid (TPA), and 1,570 g (10.4 mol) of hydroxyacetanilide (APAP) were added to the reactor while rotating the stirrer, and then 12,300 g (120.5 mol) of acetic anhydride was further added, and then the foregoing components were mixed in the batch reactor.

[0068] 2. 2.7 g of potassium acetate and 10.8 g of magnesium acetate as catalysts were added to the reactor, and then nitrogen was injected to create an inert atmosphere inside the reactor.

[0069] 3. After heating the reactor to a temperature that allows acetic anhydride to reflux in the batch reactor within a 1-hour period, the hydroxyl groups of the monomers were acetylated at this temperature for 2 hours, and then the excess unreacted acetic anhydride and acetic acid generated from the acetylation of the hydroxyl groups were removed. Thereafter, the reactor was heated to 320 °C at a heating rate of 0.5 °C / minute to prepare a liquid crystal polyester prepolymer, and then the liquid crystal polyester prepolymer was cooled and solidified while being discharged through the lower valve of the reactor, and then it was primarily pulverized to obtain 32,000 g of a liquid crystal polyester prepolymer.

[0070] 4. The liquid crystal polyester prepolymer was pulverized a second time using a fine grinder and then introduced into a rotary heating device. Thereafter, polycondensation of the liquid crystal polyester prepolymer was carried out as follows: the prepolymer was heated to 200 °C for 2 hours while injecting nitrogen into the rotary heating device at a flow rate of 25 L / min, the temperature of the prepolymer was maintained at 200 °C for 2 hours, the prepolymer was heated to 285 °C at a heating rate of 0.2 °C / min, and the temperature of the heating device was maintained at 285 °C for 3 hours.

[0071] 5. After completion of the polycondensation of the prepolymer, a liquid crystal polyester resin was finally obtained. The obtained liquid crystal polyester resin had a melting point of 330 °C.

[0072] Example 1. Preparation of a liquid crystal polyester resin composition

[0073] 1. 76.7 wt% of the liquid crystal polyester resin prepared in the preparation example (hereinafter referred to as "LCP resin") was mixed with 3 wt% of carbon black, 17 wt% of mica, 2 wt% of an ethylene-methyl acrylate copolymer as a fibril inhibitor, 1 wt% of molybdenum disulfide, and 0.3 wt% of an esterification inhibitor. Details of the foregoing components are shown in Table 1.

[0074] 2. The resulting mixture was melt-kneaded in a twin-screw extruder (L / D: 44, diameter: 30 mm) at a barrel temperature of 340 °C, by-products were then removed by venting, and then the melt-kneaded mixture was pelletized, thereby preparing a liquid crystal polyester resin composition in pellet form.

[0075] 3. The prepared pellets were mixed in a mixer (JITD-50KW, JEIL Machinery Co., Ltd.) for 30 minutes and then dried in a hot air dryer (JIB-100KW, JEIL Machinery Co., Ltd.) at 150 °C for 4 hours.

[0076] Table 1

[0077]

[0078]

[0079] Examples 2 to 6: Preparation of a liquid crystal polyester resin composition

[0080] A liquid crystal polyester resin composition was prepared in the same manner as in Example 1 except that the content of each component was changed as listed in Table 2.

[0081] Table 2

[0082] Component Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 LCP resin 76.7 74.7 72.7 70.7 74.9 74 Carbon black 3 3 3 3 3 3 Mica 17 17 17 17 17 17 Fibril inhibitor 2 4 6 8 4 4 Molybdenum disulfide 1 1 1 1 1 1 Esterification inhibitor 0.3 0.3 0.3 0.3 0.1 1.0

[0083] Comparative Examples 1 to 4: Preparation of Liquid Crystal Polyester Resin Compositions

[0084] Except for changing the content of each component as listed in Table 3, the liquid crystal polyester resin compositions were prepared in the same manner as in Example 1.

[0085] Table 3

[0086]

[0087]

[0088] Experimental Example 1: Melt Viscosity of Liquid Crystal Polyester Resin Compositions

[0089] Using a capillary rheometer (RG20, Göttfert Inc.), the melt viscosity of each of the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4 was measured under the conditions of a barrel temperature of 350 °C and a shear rate of 1,000 s -1 . The results are shown in Table 4.

[0090] Experimental Example 2: Impact Strength of Liquid Crystal Polyester Resin Compositions

[0091] Samples sized 12.7 mm × 65 mm × 3.2 mm (width × length × thickness) were prepared from each of the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4.

[0092] The notchless impact strength of the samples was evaluated according to American Society for Testing Material (ASTM) D256. The results are shown in Table 4.

[0093] Experimental Example 3: Weld Line Impact Strength of Liquid Crystal Polyester Resin Compositions

[0094] Samples sized 12.4 mm × 80 mm × 3 mm (width × length × thickness) were prepared from each of the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4. When preparing the samples, gates were positioned on both sides of the mold cavity such that the resin composition could be injected into the mold cavity, so that a weld line was formed at the center of the sample where the resin flows from the two gates met.

[0095] The weld line impact strength in the notchless state was measured by applying an impact to the weld line region of the prepared samples using an Izod impact tester according to ASTM D256. The results are shown in Table 4.

[0096] Experimental Example 4: Resistance to Sink Mark of Liquid Crystal Polyester Resin Composition

[0097] 1. Samples sized 12.4 mm × 80 mm × 3 mm (width × length × thickness) were prepared by injection molding each of the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4.

[0098] 2. The prepared samples were mounted on a dust simulator, and then a 15 g ball was continuously dropped onto the samples from a height of 10 cm 70 times.

[0099] 3. After the continuous drop test, the sink mark depth (μm) and sink mark volume (μm 3 ) of the samples were measured using a 3D tiling technique with an optical microscope (XY-GB2, HIROX Co., Ltd.).

[0100] 4. Processes 1 to 3 constituted a single test, and six single tests were performed on each sample, and then the average sink mark depth (μm) and average sink mark volume (μm 3 ) were calculated. The results are shown in Table 4.

[0101] Experimental Example 5: Resistance to fibril formation of liquid crystal polyester resin composition

[0102] 1. Samples sized 12.4 mm × 80 mm × 3 mm (width × length × thickness) were prepared by injection molding each of the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4, and then the samples were conditioned in a constant temperature / constant humidity chamber at 23 °C and 50% RH for at least 8 hours.

[0103] 2. The samples were cleaned in an alkaline aqueous solution (1%) for 8 minutes at room temperature using a 40 kHz ultrasonic cleaner and then cleaned in ultrapure water for 2 minutes, and then dried in a dryer at 80 °C for 30 minutes.

[0104] 3. The samples were bubbled at room temperature for 10 seconds, and then the presence of fibrils was observed under an optical microscope (XY-GB2, HIROX Co., Ltd.).

[0105] 4. For each of the resin compositions of Examples 1 to 5 and Comparative Examples 1 to 4, 100 samples were tested.

[0106] 5. After processes 1 to 4 were completed, the number of samples showing fibril formation was counted. When the number of samples showing fibril formation was 5 or less, the corresponding resin composition was rated "good", while when the number of samples showing fibril formation was greater than 5, the corresponding resin composition was rated "poor". The evaluation results are shown in Table 4.

[0107] Table 4

[0108]

[0109] The liquid crystal polyester resin compositions of Examples 1 to 6 exhibited a melt viscosity of 15 Pa·s to 20 Pa·s. These results indicate that the resin compositions of Examples 1 to 6 have appropriate fluidity for manufacturing high-quality molded articles. In contrast, the liquid crystal polyester resin compositions of Comparative Example 2 and Comparative Example 3 did not exhibit appropriate melt viscosity. The inappropriate melt viscosity of the resin composition of Comparative Example 2 can be attributed to the excessive presence of a fibril inhibitor, while the inappropriate melt viscosity of the resin composition of Comparative Example 3 can be attributed to the absence of an esterification inhibitor.

[0110] The liquid crystal polyester resin compositions of Examples 1 to 6 exhibited good impact strength of 80 kJ / m 2 or greater than 80 kJ / m 2 , thus demonstrating resistance to internal / external impact, resistance to dust generation, and stability against internal / external impact or friction. In contrast, the liquid crystal polyester resin compositions of Comparative Example 1 and Comparative Example 3 exhibited poor impact strength of less than 80 kJ / m 2 (Comparative Example 1: about 61 kJ / m 2 , Comparative Example 3: about 44 kJ / m 2 ), indicating that the molded articles are more susceptible to damage due to internal / external impact. The poor impact strength of the resin composition of Comparative Example 1 can be attributed to the absence of a fibril inhibitor, while the poor impact strength of the resin composition of Comparative Example 3 can be attributed to the absence of an esterification inhibitor.

[0111] The liquid crystal polyester resin compositions of Examples 1 to 6 exhibited good weld line impact strength of more than 20 J / m, thus demonstrating resistance to internal / external impact, resistance to dust generation, and stability against internal / external impact or friction. In contrast, the liquid crystal polyester resin compositions of Comparative Example 1 and Comparative Example 3 exhibited poor weld line impact strength of 20 J / m or less than 20 J / m (Comparative Example 1: about 20 J / m, Comparative Example 3: about 14 J / m), indicating that the molded articles are more susceptible to damage due to internal / external impact. The poor weld line impact strength of the resin composition of Comparative Example 1 can be attributed to the absence of a fibril inhibitor, while the poor weld line impact strength of the resin composition of Comparative Example 3 can be attributed to the absence of an esterification inhibitor.

[0112] The liquid crystal polyester resin compositions of Examples 1 to 6 exhibited a dimple depth of less than about 21 μm and a dimple volume of about 11,000,000 μm 3 or less than 11,000,000 μm 3 thereby showing resistance to dust generation caused by impact. In contrast, the liquid crystal polyester resin composition of Comparative Example 2 exhibited a dimple depth of about 23.8 μm and a dimple volume of about 14,840,811 μm 3 and the liquid crystal polyester resin composition of Comparative Example 4 exhibited a dimple depth of about 25.5 μm and a dimple volume of 16,482,994 μm 3 indicating that the resin compositions of Comparative Example 2 and Comparative Example 4 had poor dimple resistance. The poor dimple resistance of the resin composition of Comparative Example 2 can be attributed to the excessive presence of the fibril inhibitor, while the poor dimple resistance of the resin composition of Comparative Example 4 can be attributed to the excessive presence of the esterification inhibitor.

[0113] The liquid crystal polyester resin compositions of Examples 1 to 6 showed high resistance to fibril formation caused by impact or friction, where 5 or fewer out of 100 samples showed fibril formation. For example, if the number of samples showing fibril formation exceeds 5, fibrils are likely to detach from the surface of the camera module components made of the corresponding resin composition during the assembly of the camera module. The deposition of the detached fibrils on the camera lens or similar components can cause defects in the camera module. Therefore, reducing fibril formation can reduce the defect rate during the assembly of the camera module, thereby contributing to an increase in the number of pixels related to higher camera performance.

[0114] In contrast, the liquid crystal polyester resin compositions of Comparative Example 1 and Comparative Example 4 showed poor resistance to fibril formation, with 37 samples showing fibril formation (Comparative Example 1) and 19 samples showing fibril formation (Comparative Example 4), respectively. The poor resistance of the resin composition of Comparative Example 1 to fibril formation can be attributed to the absence of the fibril inhibitor, while the poor resistance of the resin composition of Comparative Example 4 to fibril formation can be attributed to the excessive presence of the esterification inhibitor.

[0115] Although some embodiments have been described herein, it should be understood that these embodiments are provided for illustrative purposes only and should not be construed as limiting the present invention in any way, and those skilled in the art can make various modifications, changes, alterations, and equivalent embodiments without departing from the spirit and scope of the present invention.

[0116] [Description of Symbols]

[0117] None.

Claims

1. A liquid crystal polyester resin composition, comprising: Liquid crystal polyester resin; fibril inhibitors; Esterification inhibitors; and Filler. 2 . The liquid crystal polyester resin composition according to claim 1 , wherein the fibril inhibitor comprises a compound including a repeating unit derived from an α-olefin and a repeating unit derived from an α,β-unsaturated carboxylic acid or an ester thereof.

3. The liquid crystal polyester resin composition according to claim 1, wherein the fibril inhibitor comprises at least one selected from the group consisting of ethylene-(meth)acrylic acid copolymer, ethylene-methyl (meth)acrylic acid copolymer, ethylene-ethyl (meth)acrylic acid copolymer and ethylene-butyl (meth)acrylic acid copolymer. 4 . The liquid crystal polyester resin composition according to claim 1 , wherein the esterification inhibitor comprises a phosphite compound. 5 . The liquid crystal polyester resin composition according to claim 1 , wherein the filler comprises a carbon-based filler and an inorganic filler.

6. The liquid crystal polyester resin composition according to claim 5, comprising: 55 wt % to 85 wt % of the liquid crystal polyester resin; 2 wt % to 8 wt % of said fibril inhibitor; 0.1 wt % to 1.0 wt % of said esterification inhibitor; 1 wt % to 5 wt % of the carbon-based filler; as well as 10 wt % to 30 wt % of the inorganic filler. 7 . The liquid crystal polyester resin composition according to claim 5 , wherein the carbon-based filler comprises at least one selected from the group consisting of carbon black, graphite, and carbon nanotubes.

8. The liquid crystal polyester resin composition according to claim 5, wherein the inorganic filler comprises at least one selected from the group consisting of serpentine, montmorillonite, talc, mica, chlorite, glass flakes, silicon dioxide, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, clay, siliceous earth, wollastonite, iron oxide, titanium oxide, zinc oxide, aluminum oxide, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, silicon carbide, silicon nitride, boron nitride and potassium titanate. 9 . The liquid crystal polyester resin composition according to claim 1 , further comprising: a lubricant. 10 . The liquid crystal polyester resin composition according to claim 1 , wherein a molded article formed from the liquid crystal polyester resin composition has a weld line impact strength of more than 20 J / m. 11 . The liquid crystal polyester resin composition according to claim 1 , wherein a molded article formed from the liquid crystal polyester resin composition has a concave depth of less than 21 μm.

12. The liquid crystal polyester resin composition according to claim 1, wherein a molded article formed from the liquid crystal polyester resin composition has a diameter of less than 11,000,000 μm. 3 The volume of the depression.

13. A molded product produced from the liquid crystal polyester resin composition according to claim 1. 14 . An electronic component material comprising the liquid crystal polyester resin composition according to claim 1 .

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