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

Abstract

To provide: a liquid crystal polyester composition that can reduce physical damage caused by internal and external friction and internal and external impact, have improved impact strength and weld line impact strength, and minimize fibril and dust generation; and an electronic component material including the same.SOLUTION: A liquid crystal polyester resin composition comprises a liquid crystal polyester resin, a fibril inhibitor, an esterification inhibitor, and fillers.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a liquid crystal polyester resin composition, a molded article, and an electronic component material containing the same, and more specifically, to a liquid crystal polyester resin composition, a molded article, and an electronic component material exhibiting excellent weld line impact strength and low dust characteristics.

Background Art

[0002] Liquid crystal polyester resin means a molten polyester resin having a property that molecular chains in the polymer are regularly arranged parallel to each other in a molten state. The state of each molecule thus arranged is usually referred to as a liquid crystal state or a nematic phase of a liquid crystal substance, and such molecules in the polymer are generally thin, long, and flat, and exhibit very high mechanical strength, electrical properties, and heat resistance along the long chain of the molecule.

[0003] Resin compositions containing liquid crystal polyester resin have high heat resistance and high flow characteristics and are widely used as materials for various electrical / electronic products. In addition, small portable electronic products such as notebook computers are becoming thinner and lighter while having excellent performance, so the demand for liquid crystal polyester resin compositions having excellent moldability is increasing.

[0004] However, the liquid crystal polyester resin composition has a property that the molten polymer does not lose its crystal structure even during flow. When injecting into a molded article having a complex structure, a weld line, which is a boundary portion where the resins meet during the molding process, is formed. Since the strength of such a weld line is very weak, the molded article may be damaged by external or internal impacts and friction.

[0005] In addition, the molded article of the liquid crystal polyester resin composition may undergo fibrillation, in which the surface is peeled off and fuzz is generated due to ultrasonic cleaning or friction with other members. When the molded article of the liquid crystal polyester resin composition is used as an electronic component in an electronic device, foreign matter such as dust and fibrils that fall off from the fibrillated portion may significantly reduce the performance of the electronic device.

[0006] For example, in the case of electronic components, particularly optical devices having lenses, if dust such as dirt and dust adheres to the lens, the optical properties may be significantly degraded. When a camera module is assembled or the functions of the camera module are operated, fibrillation may progress. Specifically, when the camera autofocus function is exercised, dust may be generated from the surface of the components due to the sliding movement of the camera module components, and dust is also likely to be generated when the device is impacted or dropped. In recent years, miniaturization of peripheral electronic devices and each accessory used inside electronic devices has become essential, and as a result, there has been an emerging need to manufacture semiconductor and optical material components that are sensitive to dust using electronic component materials that generate less dust.

[0007] In this regard, Korean Patent Publication No. 10-2014-0007792 discloses a liquid crystal polyester resin composition capable of obtaining a molded product that is difficult to fibrillate. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention provides a liquid crystalline polyester composition that reduces physical damage caused by internal and external friction and internal and external impact, improves impact strength and impact strength at weld lines, and minimizes the generation of fibrils and dust, and an electronic component material containing the same. [Means for solving the problem]

[0009] According to one aspect of the present invention, the present invention can provide a liquid crystal polyester resin composition containing a liquid crystal polyester resin; a fibril inhibitor; an esterification reaction inhibitor; and a filler.

[0010] Preferably, the fibril inhibitor is a compound containing a repeating unit derived from an α-olefin and a repeating unit derived from an α,β-unsaturated carboxylic acid or its ester, and a liquid crystal polyester resin composition can be provided.

[0011] Preferably, the fibril inhibitor is one or more selected from the group consisting of ethylene-(meth)acrylic acid copolymer, ethylene-(meth)methyl acrylate copolymer, ethylene-(meth)ethyl acrylate copolymer, and ethylene-(meth)butyl acrylate copolymer, and a liquid crystal polyester resin composition can be provided.

[0012] Preferably, the esterification reaction inhibitor is a phosphite compound, and a liquid crystal polyester resin composition can be provided.

[0013] Preferably, the filler includes a carbon-based filler and an inorganic filler, and a liquid crystal polyester resin composition can be provided.

[0014] Preferably, the liquid crystal polyester resin is 55% by weight or more and 85% by weight or less; the fibril inhibitor is 2% by weight or more and 8% by weight or less; the esterification reaction inhibitor is 0.1% by weight or more and 1.0% by weight or less; the carbon-based filler is 1% by weight or more and 5% by weight or less; and the inorganic filler is 10% by weight or more and 30% by weight or less, and a liquid crystal polyester resin composition can be provided.

[0015] Preferably, the carbon-based filler is one or more selected from the group consisting of carbon black, graphite, and carbon nanotubes, and a liquid crystal polyester resin composition can be provided.

[0016] Preferably, the inorganic filler is at least one selected from the group consisting of serpentine, montmorillonite, talc, micas (biotite, muscovite, phlogopite), chlorite, glass flakes, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, wollastonite, iron oxide, titanium oxide, zinc oxide, alumina, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, silicon carbide, silicon nitride, boron nitride, and potassium titanate, and a liquid crystal polyester resin composition can be provided.

[0017] Preferably, a liquid crystal polyester resin composition further containing a lubricant can be provided.

[0018] Preferably, a liquid crystal polyester resin composition can be provided in which the weld line impact strength of a molded article produced from the liquid crystal polyester resin composition exceeds 20 J / m.

[0019] Preferably, a liquid crystal polyester resin composition can be provided in which the dent depth of a molded article produced from the liquid crystal polyester resin composition is less than 21 μm.

[0020] Preferably, a liquid crystal polyester resin composition can be provided in which the dent volume of a molded article produced from the liquid crystal polyester resin composition is less than 11,000,000 μm 3 3.

[0021] In another aspect of the present invention, the present invention can provide a molded article produced from the liquid crystal polyester resin composition.

[0022] In still another aspect of the present invention, the present invention can provide an electronic component material containing the liquid crystal polyester resin composition.

Advantages of the Invention

[0023] The liquid crystal polyester resin composition according to the present invention can minimize the generation of dust due to internal and external impacts and friction while maintaining the original physical properties of the liquid crystal polyester resin, such as excellent mechanical, thermal, electrical properties, and flame retardancy.

[0024] The liquid crystal polyester resin composition, molded article, and electronic component material containing the same according to the present invention have excellent impact strength and weld line impact strength, and the generation of dust and fibrils is suppressed against internal and external friction and impact.

[0025] In addition, the liquid crystal polyester resin composition, molded article, and electronic component material containing the same according to the present invention minimize the number of generated dust and fibrils, have excellent weld line impact strength, and can be used as a component material for electronic products that are sensitive to internal and external impacts and internal and external friction. In particular, the present invention is applied to components for camera modules or components for camera modules of mobile phones, and can maintain or improve optical performance such as the number of pixels and image quality.

Mode for Carrying Out the Invention

[0026] Hereinafter, the present invention will be described.

[0027] All terms (including technical and scientific terms) used in this specification can be used in a meaning commonly understood by those having ordinary knowledge in the technical field to which the present invention pertains, unless otherwise defined. Also, each commonly used pre-defined term is not ideally or excessively interpreted unless clearly and specifically defined.

[0028] Also, throughout this specification, when one part "includes" one component, this means that, unless otherwise stated to the contrary, it does not exclude other components, but may further include other components.

[0029] As an example of the present invention, the liquid crystal polyester resin composition can include a liquid crystal polyester resin, a fibril inhibitor, an esterification reaction inhibitor, and a filler.

[0030] The liquid crystal polyester resin used in the present invention exhibits liquid crystallinity in a molten state, and is preferably melted at a temperature of 450 °C or lower.

[0031] When considering its mechanical strength and injection moldability, the liquid crystal polyester resin can have a weight average molecular weight of about 10,000 to 300,000, preferably about 10,000 to 50,000. When the weight average molecular weight of the liquid crystal polyester resin is less than 10,000, the mechanical strength becomes poor and breakage of the molded product may occur. On the other hand, when the weight average molecular weight exceeds 300,000, injection molding may become difficult due to a decrease in the fluidity of the resin.

[0032] The liquid crystal polyester resin may be contained in an amount of about 55% by weight or more to about 85% by weight or less, preferably about 60% by weight or more to about 80% by weight or less, and more preferably about 65% by weight or more to about 80% by weight or less, based on the total weight of the liquid crystal polyester resin composition. When the liquid crystal polyester resin component is contained in an amount of less than about 55% by weight, the fluidity of the resin composition decreases and micro injection molding may become difficult. When the liquid crystal polyester resin component is contained in an amount exceeding about 85% by weight, the fluidity of the resin composition becomes excessively large, and the strength and heat resistance of the molded products and electronic components produced therefrom may deteriorate.

[0033] As the liquid crystal polyester resin, one or more selected from the group consisting of liquid crystal polyester amide, liquid crystal polyester ether, liquid crystal polyester carbonate, and liquid crystal polyester imide may be used.

[0034] The liquid crystal polyester resin is preferably an all-aromatic liquid crystal polyester composed only of aromatic compounds as monomer substances. Typical examples of the all-aromatic liquid crystal polyester resin include resins produced by polymerizing (polycondensing) one or more compounds selected from the group consisting of aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, aromatic diols, aromatic hydroxyamines, and aromatic diamines; resins produced by polymerizing two or more aromatic hydroxycarboxylic acids; resins produced by polymerizing one or more compounds selected from the group consisting of aromatic dicarboxylic acids, aromatic diols, aromatic hydroxyamines, and aromatic diamines; and resins produced by polymerizing a polyester such as polyethylene terephthalate and an aromatic hydroxycarboxylic acid.

[0035] The liquid crystal polyester resin can be produced by polycondensing one or more aromatic monomers to form a prepolymer of the liquid crystal polyester, and then subjecting the formed prepolymer to solid-phase polycondensation. By-products generated during the solid-phase polycondensation reaction can be removed by purging with an inert gas or by vacuum.

[0036] The liquid crystal polyester resin that can be included in the resin composition of the present invention can be produced, for example, by polymerizing one or more monomers selected from the group including hydroxybenzoic acid (HBA), hydroxynaphthoic acid (HNA), biphenol (BP), terephthalic acid (TPA), and hydroxyacetanilide (APAP).

[0037] For example, a liquid crystal polyester resin can be polymerized by including 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 hydroxyacetanilide (APAP). The liquid crystal polyester resin polymerized with such a combination of mol% can ensure fluidity, and the resin composition containing the same can improve mechanical properties such as the impact strength of the product while minimizing the generation of dust and fibrils.

[0038] The fibril inhibitor in the present invention can improve the impact resistance of the liquid crystal polyester resin composition against internal and external impacts and reduce the generation of fibrils. As the fibril inhibitor, a copolymer containing a repeating unit derived from an α-olefin and a repeating unit derived from an α,β-unsaturated carboxylic acid or an ester of an α,β-unsaturated carboxylic acid can be used.

[0039] Examples of α-olefins include α-olefins having 2 to 10 carbon atoms such as ethylene, propylene, butene, hexene, and octene, and typically ethylene may be used. Examples of α,β-unsaturated carboxylic acids or esters of α,β-unsaturated carboxylic acids include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, etc., and methacrylic acid may be particularly preferred in some cases.

[0040] Examples of copolymers containing a repeating unit derived from an α-olefin and a repeating unit derived from an α,β-unsaturated carboxylic acid or its ester as the fibril inhibitor include ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid methyl copolymer, ethylene-(meth)acrylic acid ethyl copolymer, ethylene-(meth)acrylic acid butyl copolymer, etc., and preferably, an ethylene-methacrylic acid copolymer can be used.

[0041] The fibril inhibitor may be contained in an amount of about 2% by weight or more to about 8% by weight or less based on the total weight of the liquid crystal polyester resin composition. When the fibril inhibitor is less than about 2% by weight, the impact strength is poor and a large amount of fibrils may be generated after washing the molded product. When the fibril inhibitor exceeds about 8% by weight, it becomes difficult to obtain a good molded product due to the change in fluidity caused by the decrease in the melt viscosity of the molded product, the mechanical properties deteriorate, and a large amount of dust may be generated due to the increase in the dent depth (μm) and dent volume (μm 3 ).

[0042] The esterification reaction inhibitor can be used to improve and enhance the melt viscosity and weld line impact strength of the liquid crystal polyester resin composition. Since the manufacturing and processing processes 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 reaction inhibitor must not be decomposed at a high temperature of about 300°C to 400°C. Examples of the esterification reaction inhibitor include phosphite-based compounds. Specifically, pentadecyl phosphite, hexadecyl phosphite, heptadecyl phosphite, octadecyl phosphite, nonadecyl phosphite, icosyl phosphite, etc. can be mentioned. Preferably, one or more selected from the group consisting of heptadecyl phosphite, octadecyl phosphite, and nonadecyl phosphite can be used.

[0043] The esterification reaction inhibitor may be contained in an amount of about 0.1% by weight or more and about 1.0% by weight or less based on the total weight of the liquid crystal polyester resin composition. When the esterification reaction inhibitor is less than about 0.1% by weight, the melt viscosity is low, so it becomes difficult to obtain a good molded product due to a decrease in fluidity, and the molded product may be damaged due to inferior impact strength and weld line impact strength. When the esterification reaction inhibitor exceeds about 1.0% by weight, the dent depth (μm) and dent volume (μm 3 ) increase, and the effect of suppressing the generation of fibrils on the surface of the molded product also decreases, so problems due to dust and fibrils may occur.

[0044] The molded product of the liquid crystal polyester resin composition added with the fibril inhibitor and the esterification reaction inhibitor suppresses the generation of fibrils on the surface and has excellent weld line impact strength, so it can prevent the molded product from being damaged due to internal and external impacts and friction, etc.

[0045] The filler can include all carbon-based fillers and inorganic fillers.

[0046] As the carbon-based filler, one or more selected from the group consisting of carbon black, graphite, and carbon nanotubes can be used alone or in combination, and preferably, carbon black can be used. The carbon-based filler may be contained in an amount of about 1% by weight or more and about 5% by weight or less based on the total weight of the liquid crystal polyester resin composition. For example, carbon black can be used to ensure light-shielding properties, and may be contained in an amount of about 1% by weight or more and about 5% by weight or less based on the total weight of the liquid crystal polyester resin composition. When the amount of carbon black is less than about 1% by weight, the jet-black property of the liquid crystal polyester resin composition may decrease, making it difficult to sufficiently ensure light-shielding properties. When the amount of carbon black exceeds about 5% by weight, it may not be uniformly dispersed in the liquid crystal polyester resin composition and may agglomerate, which can cause a decrease in physical properties and an increased possibility of the aggregates being separated as dust.

[0047] The inorganic filler can be used to improve mechanical strength, heat resistance, and dent resistance due to impact. The blending of the inorganic filler with the liquid crystal polyester resin must be carried out so as not to cause damage to the mechanical properties such as strength, rigidity, and hardness, heat resistance, and electrical properties of the polyester resin. Any non-fibrous filler can be used as the inorganic filler, and examples of non-fibrous fillers include plate-like fillers and granular fillers. The inorganic filler can be contained in an amount of about 10% by weight or more and about 30% by weight or less based on the total weight of the liquid crystal polyester resin composition.

[0048] The plate-like filler can play a role in improving mechanical physical properties and heat resistance and imparting dimensional stability to the molded product. Examples of the plate-like filler include serpentine, montmorillonite, talc, micas such as mica (biotite, muscovite, phlogopite), chlorite, and glass flakes.

[0049] Examples of granular fillers include silicates such as silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, and wollastonite; metal oxides such as iron oxide, titanium oxide, zinc oxide, and alumina; metal carbonates such as calcium carbonate and magnesium carbonate; metal sulfates such as calcium sulfate and barium sulfate; silicon carbide; silicon nitride; boron nitride; and potassium titanate.

[0050] As the inorganic filler, one or more types of plate-like fillers, one or more types of granular fillers, or one or more types of each of the plate-like filler and the granular filler can be used.

[0051] The liquid crystal polyester resin composition of the present invention can further contain a lubricant. Examples of the lubricant include transition metal compounds containing elements belonging to Group 6 of the periodic table, specifically, molybdenum-based compounds, tungsten-based compounds, and chromium-based compounds.

[0052] When a lubricant is included, the fluidity during high-temperature injection increases, the orientation of the polymer chains of the liquid crystal polyester resin is maximized, the flexural strength, flexural modulus, impact strength, and weld line impact strength are improved, and the generation of dust and fibrils due to internal and external impacts and friction can be minimized.

[0053] As the lubricant, transition metal sulfides containing elements belonging to Group 6 of the periodic table can be used. Specifically, molybdenum disulfide (MoS 2 ), molybdenum diselenide (MoSe 2 ), molybdenum selenosulfide (MoSSe), molybdenum trioxide (MoO 3 ), tungsten disulfide (WS 2 ), tungsten diselenide (WSe 2 ), tungsten selenosulfide (WSSe), tungsten trioxide (MoO 3 ), chromium disulfide (CrS 2 ), chromium diselenide (CrSe 2 ), chromium selenosulfide (CrSSe), and chromium trioxide (CrO 3One or more selected from the group consisting of can be used. As the lubricant, preferably, molybdenum disulfide (MoS 2 ) or tungsten disulfide (WS 2 ) can be used, and more preferably, molybdenum disulfide (MoS 2 ) can be used.

[0054] The sulfide of a transition metal has a sandwich-like layered structure in which a transition metal layer is located between two layers composed of sulfur. A weak van der Waals force acts between each layer, and each layer has the characteristics of being slippery and having a low coefficient of friction. For example, molybdenum disulfide among transition metal sulfides can be added to plastics to obtain a composite with low frictional resistance and high strength, or can be used to obtain a self-lubricating composite material for high temperatures by vacuum depositing it on the surface of other substances.

[0055] The lubricant may be used in the range of more than about 0.5% by weight to less than about 10% by weight, preferably in the range of more than about 0.5% by weight to about 5% by weight or less, more preferably in the range of about 1% by weight or more to about 5% by weight or less, and very preferably in the range of about 1% by weight or more to about 3% by weight or less, based on the total weight of the liquid crystal polyester resin composition.

[0056] When the lubricant contains more than about 10% by weight, appropriate dispersion in the liquid crystal polyester resin composition is not achieved, so the extrusion processability decreases, and as a result, the mechanical properties can become very poor. Also, due to the poor mechanical properties, problems such as an increase in the generation of dust and fibrils may occur.

[0057] When the lubricant contains less than about 0.5% by weight, the orientation of the polymer chains becomes low above the melting point of the liquid crystal polyester resin, and the improvement effect on the mechanical properties is not sufficiently achieved, and the amount of dust and fibrils generated thereby may also increase.

[0058] The liquid crystal polyester resin composition of the present invention contains a fibril inhibitor, an esterification reaction inhibitor, and a filler, and can improve impact strength and dent characteristics. As a result, the number of dust and fibrils generated by internal and external impacts and friction can be minimized and suppressed. Further, the liquid crystal polyester resin composition of the present invention can minimize the particle size of the generated dust and fibrils and can have excellent weld line impact strength. In addition, the liquid crystal polyester resin composition of the present invention can improve the impact strength of weld lines appearing in molded articles having complex structures and minimize and prevent damage caused by internal and external impacts. In particular, when applied to camera module parts, it can greatly contribute to maintaining and improving optical performance such as the number of pixels and image quality.

[0059] The present invention can produce a molded article or an electronic component material from a liquid crystal polyester resin composition containing the above-described respective constituent components. The liquid crystal polyester resin composition of the present invention has the characteristic of increased polymer chain orientation, whereby the molded article or the electronic component material of the present invention has excellent mechanical strength including weld line impact strength and can minimize the generation of dust and fibrils. Specifically, the liquid crystal polyester resin composition of the present invention is applied to a camera module part of a mobile phone or a camera module part of a smartphone and can contribute to maintaining and improving optical performance such as the number of pixels and image quality.

[0060] After drying the liquid crystal polyester resin composition of the present invention, the melt viscosity evaluated using a melt viscosity measuring machine can show a range of 15 Pa·s or more and 20 Pa·s or less.

[0061] After drying the liquid crystal polyester resin composition of the present invention, the impact strength evaluated by producing a test piece using an injection machine can show an improved impact strength exceeding 80 kJ / m 2 2.

[0062] After drying the liquid crystal polyester resin composition of the present invention, the weld line impact strength evaluated by fabricating test pieces using an injection molding machine can exhibit an improved impact strength exceeding 20 J / m.

[0063] After drying the liquid crystal polyester resin composition of the present invention, test pieces were fabricated using an injection molding machine, and the depth (μm) and volume (μm 3 ) of the dent portion measured through a dent replication tester were less than 21 μm and less than 11,000,000 μm 3 , respectively.

[0064] Hereinafter, the present invention will be specifically described through the following examples, and the present invention is not limited by these examples.

[0065] Production Example: Production of Liquid Crystal Polyester Resin

[0066] 1. 13,000 g (127.3 mol) of acetic anhydride was charged into a 200 L batch reactor, and while rotating the stirrer, 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 (BP), 6,500 g (39.6 mol) of terephthalic acid (TPA), and 1,570 g (10.4 mol) of hydroxyacetanilide (APAP) were charged. Then, 12,300 g (120.5 mol) of acetic anhydride was further charged, and these were mixed in the batch reactor.

[0067] 2. 2.7 g of potassium acetate catalyst and 10.8 g of magnesium acetate catalyst were added, and nitrogen was injected to make the internal space of the reactor in an inert state.

[0068] 3. The temperature of the reactor was raised to the reflux temperature of acetic anhydride inside the batch reactor over 1 hour, and at this temperature, the hydroxy groups of each monomer were acetylated over 2 hours. The acetic acid produced in the acetylation reaction and the unreacted acetic anhydride introduced in excess were removed. The temperature of the reactor was raised to 320 °C at a rate of 0.5 °C / min to produce a liquid crystal polyester prepolymer, which was then discharged through the lower valve while being cooled and solidified, and was primarily pulverized to obtain 32,000 g of the liquid crystal polyester prepolymer.

[0069] 4. The liquid crystal polyester prepolymer was secondarily pulverized using a fine pulverizer and then charged into a rotary heating device. While flowing nitrogen through the rotary heating device at a flow rate of 25 L / min, the temperature was raised to 200 °C over 2 hours, maintained at 200 °C for 2 hours, then raised to 285 °C at a rate of 0.2 °C / min, and then a polycondensation reaction was carried out while maintaining for 3 hours.

[0070] 5. After the polycondensation reaction, a liquid crystal polyester resin was finally obtained, and the melting point of the produced resin was 330 °C.

[0071] Example 1. Production of Liquid Crystal Polyester Resin Composition

[0072] 1. 76.7 wt% of the liquid crystal polyester resin (hereinafter referred to as LCP resin) produced in the production example, 3 wt% of carbon black, 17 wt% of mica, 2 wt% of an ethylene-methacrylic acid copolymer as a fibril inhibitor, 1 wt% of molybdenum disulfide, and 0.3 wt% of an esterification reaction inhibitor were mixed. The components used are specifically shown in Table 1 below.

[0073] 2. It was melted and kneaded with a twin-screw extruder (L / D: 44, diameter: 30 mm). The barrel temperature of the extruder during melt-kneading was 340 °C, and after removing by-products through vacuum, it was pelletized.

[0074] 3. The pelletized liquid crystal polyester resin composition was mixed for 30 minutes using a mixer (First Industry Equipment, JITD-50KW), and then dried at 150°C for 4 hours using a hot air dryer (First Industry Equipment, JIB-100KW).

[0075]

Table 1

[0076] Production of Liquid Crystal Polyester Resin Compositions of Examples 2 to 6

[0077] The liquid crystal polyester resin compositions of Examples 2 to 6 were produced in the same manner as in Example 1 and with the composition ratios shown in Table 2 below.

[0078]

Table 2

[0079] Production of Liquid Crystal Polyester Resin Compositions of Comparative Examples 1 to 4

[0080] The liquid crystal polyester resin compositions of Comparative Examples 1 to 4 were produced in the same manner as in Example 1 and with the components and composition ratios shown in Table 3 below.

[0081]

Table 3

[0082] Test Example 1. Melt Viscosity of Liquid Crystal Polyester Resin Composition

[0083] For each of the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4, the melt viscosity was measured using a capillary rheometer (GOETTFERT RG20) under the conditions of a cylinder temperature of 350°C and a shear rate of 1000 sec -1 -1. The measured results are shown in Table 4.

[0084] Test Example 2. Impact Strength of Liquid Crystal Polyester Resin Composition

[0085] For each of the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4, test pieces with a width of 12.7 mm, a length of 65 mm, and a thickness of 3.2 mm were manufactured.

[0086] For each of the manufactured test pieces, the impact strength was evaluated in the un-notched state according to ASTM D256, and the results are shown in Table 4.

[0087] Test Example 3. Weld Line Impact Strength of Liquid Crystal Polyester Resin Composition

[0088] For each of the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4, test pieces with a width of 12.4 mm, a length of 80 mm, and a thickness of 3 mm were manufactured. When manufacturing the test pieces, the gates through which the resin composition is discharged were in both directions, so that the resin met from both ends of the test piece to the center of the test piece, and they were manufactured so that weld lines were formed.

[0089] For each weld line portion of each of the manufactured test pieces, the weld line impact strength was measured by applying an impact using an IZOD impact machine in the un-notched state according to ASTM D256, and the results are shown in Table 4.

[0090] Test Example 4. Dent Evaluation of Liquid Crystal Polyester Resin Composition

[0091] 1. Test pieces with a width of 12.4 mm, a length of 80 mm, and a thickness of 3 mm were manufactured by molding each of the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4 using an injection molding machine.

[0092] 2. Each of the manufactured test pieces was mounted on a dust replication tester, and a 15 g ball was continuously dropped 70 times from a height of 10 cm.

[0093] 3. After the continuous drop test, the dent depth (μm) and dent volume (μm 3 ) of each test piece were measured using a 3D tiling technique through an optical microscope (HIROX, XY-GB2).

[0094] 4.1 Process to 3 processes were combined into one test, and this was performed a total of 6 times for each test piece. The average dent depth (μm) and dent volume (μm 3 ) of each test piece are shown in Table 4.

[0095] Test Example 5. Fibril Evaluation of Liquid Crystal Polyester Resin Composition

[0096] 1. For each of the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4, after injecting test pieces with a width of 12.4 mm, a length of 80 mm, and a thickness of 3 mm, they were conditioned in a thermo-hygrostat chamber at a humidity of 50% and a temperature of 23°C for at least 8 hours.

[0097] 2. At room temperature, they were washed with a 1% alkaline aqueous solution for 8 minutes and then with ultrapure water for 2 minutes using a 40 kHz ultrasonic cleaner, and then dried in a dryer at 80°C for 30 minutes.

[0098] 3. After performing blowing at room temperature for 10 seconds, the presence or absence of fibrils was observed using an optical microscope (HIROX, XY-GB2).

[0099] 4. For the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4, 100 test pieces were measured for each.

[0100] 5. After going through the above 1 process to 3 processes, if the number of test pieces with fibrils generated among 100 test pieces was 5 or less, it was evaluated as good; if it exceeded 5, it was evaluated as bad. The evaluation results are shown in Table 4.

[0101]

Table 4

[0102] The liquid crystal polyester resin compositions of Examples 1 to 6 were confirmed to have a melt viscosity in the range of 15 Pa·s or more and 20 Pa·s or less. In this melt viscosity range, since the resin composition has fluidity suitable for the production of molded articles, molded articles of good quality can be produced. On the other hand, in the cases of Comparative Examples 2 and 3, appropriate melt viscosity values were not shown. In the case of Comparative Example 2, it is considered that an appropriate melt viscosity value was not shown due to excessive inclusion of a fibril inhibitor, and in the case of Comparative Example 3, due to non-inclusion of an esterification reaction inhibitor.

[0103] The liquid crystal polyester resin compositions of Examples 1 to 6 have an impact strength of 80 kJ / m 2 or more, and thus have excellent impact strength characteristics, resistance to internal and external impacts, and the possibility of suppressing dust generation, and it was confirmed that they have stability against external or internal impacts and friction. On the other hand, in the cases of Comparative Example 1 and Comparative Example 3, they are about 61 kJ / m 2 and about 44 kJ / m 2 respectively, and have a poor impact strength of less than 80 kJ / m 2 , so it was confirmed that there is a high possibility that the molded articles will be easily damaged by internal and external impacts. In the case of Comparative Example 1, it is considered that a poor impact strength was caused by non-inclusion of a fibril inhibitor, and in the case of Comparative Example 3, by non-inclusion of an esterification reaction inhibitor.

[0104] The liquid crystal polyester resin compositions of Examples 1 to 6 have a weld line impact strength of more than 20 J / m, and thus have excellent weld line impact strength, resistance to internal and external impacts, and the possibility of suppressing dust generation, and it was confirmed that they have stability against external or internal impacts and friction. On the other hand, in the case of Comparative Example 1, it is about 20 J / m, and in the case of Comparative Example 3, it is about 14 J / m, and they have a poor weld line impact strength of 20 J / m or less, so it was confirmed that there is a high possibility that the molded articles will be easily damaged by internal and external impacts. This is considered to be due to non-inclusion of a fibril inhibitor in the case of Comparative Example 1 and due to non-inclusion of an esterification reaction inhibitor in the case of Comparative Example 3.

[0105] The liquid crystal polyester resin compositions of Examples 1 to 6 all had a dent depth of less than about 21 μm and a dent volume of about 11,000,000 μm 3 as follows, and it was confirmed that the generation of dust due to impact could be effectively suppressed. On the other hand, in the case of Comparative Example 2, the dent depth was about 23.8 μm and the dent volume was about 14,840,811 μm 3 and in the case of Comparative Example 4, the dent depth was about 25.5 μm and the dent volume was 16,482,994 μm 3 It was confirmed that the dent characteristics deteriorated. In the case of Comparative Example 2, it is considered that poor dent characteristics were shown by containing an excessive amount of fibril inhibitor, and in the case of Comparative Example 4, by containing an excessive amount of esterification reaction inhibitor.

[0106] In the liquid crystal polyester resin compositions of Examples 1 to 6, since the number of test pieces in which fibrils occurred was 5 or less out of 100 test pieces, an excellent effect of suppressing fibrils generated by impact and friction was confirmed. For example, when the number of fibrils exceeds 5, fibrils are likely to be separated from the surface of parts in the camera module assembly process in many cases. When such separated fibrils adhere to a camera lens or the like, this can cause defects. Therefore, when the number of generated fibrils decreases, the number of defects during camera module assembly decreases, thereby promoting an improvement in the number of pixels accompanying the high performance of the camera.

[0107] In comparison, fibrils occurred in 37 test pieces in the case of Comparative Example 1 and in 19 test pieces in the case of Comparative Example 4. In the case of Comparative Example 1, it is considered that poor fibril evaluation was obtained by not containing a fibril inhibitor, and in the case of Comparative Example 4, by containing an excessive amount of esterification reaction inhibitor.

[0108] The present invention is not limited to the above-described examples, and it is obvious to those having ordinary knowledge in the technical field to which the present invention pertains that various modifications or deformations can be made and implemented without departing from the technical gist of the present invention.

Claims

1. Liquid crystal polyester resin; Fibrillation inhibitors; esterification reaction inhibitors; and A liquid crystal polyester resin composition comprising a filler.

2. 2. The liquid crystal polyester resin composition according to claim 1, wherein the fibrillation inhibitor is a compound containing 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 fibrillation inhibitor is at least one selected from the group consisting of ethylene-(meth)acrylic acid copolymer, ethylene-(meth)methyl acrylate copolymer, ethylene-(meth)ethyl acrylate copolymer, and ethylene-(meth)butyl acrylate copolymer. The liquid crystal polyester resin composition according to claim 1.

4. The liquid crystal polyester resin composition according to claim 1 , wherein the esterification reaction inhibitor is 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 is 55% by weight or more and 85% by weight or less; The fibrillation inhibitor is from 2% to 8% by weight; The esterification reaction inhibitor is present in an amount of 0.1% by weight or more and 1.0% by weight or less; the carbon-based filler is from 1% to 5% by weight; and The liquid crystal polyester resin composition according to claim 5 , wherein the inorganic filler is contained in an amount of 10% by weight or more and 30% by weight or less.

7. The liquid crystal polyester resin composition according to claim 5, wherein the carbon-based filler is 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 is 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, diatomaceous earth, wollastonite, iron oxide, titanium oxide, zinc oxide, alumina, 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 produced 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 produced from the liquid crystal polyester resin composition has a dent depth of less than 21 μm.

12. The dent volume of a molded article produced from the liquid crystal polyester resin composition is 11,000,000 μm ３ The liquid crystal polyester resin composition according to claim 1, wherein the liquid crystal polyester resin composition has a viscosity of 1000:1 or less.

13. A molded article produced from the liquid crystal polyester resin composition according to claim 1.

14. A material for electronic parts, comprising the liquid crystal polyester resin composition according to claim 1.

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