Liquid crystal polymer composition and liquid crystal polymer film

Abstract

The present invention relates to a liquid crystal polymer composition comprising silica microparticles with a surface modified to be hydrophobic and a liquid crystal polymer resin, and a liquid crystal polymer film.

Description

Technology Field

[0001] The present invention relates to a liquid crystal polymer composition and a liquid crystal polymer film. Background Technology

[0003] Recently, wireless communication is shifting to high-frequency ranges to increase communication speeds. Since wireless communication in this high-frequency range involves high transmission losses, high-frequency circuit boards utilizing insulators with low dielectric constants and dielectric loss tangents are under development; insulators using liquid crystal polymer resins are being considered as a representative example.

[0004] However, since liquid crystal polymer resins form a liquid crystal structure in a molten state, the film surface becomes significantly uneven during the solidification process after melting in film manufacturing. This uneven surface can cause defects during the lamination process with copper foil when manufacturing FCCL (Flexible Copper Clad Laminate) using liquid crystal polymer film as an insulating film, or when manufacturing multilayer PCBs (Printed Circuit Boards) applying liquid crystal polymer film as a bonding sheet, because the film fails to make sufficient contact with the copper foil due to the uneven surface.

[0005] To improve the surface uniformity of liquid crystal polymer films, there is a method to ensure uniform doping flow by using a stationary mixing stirrer at the die inlet; however, since the film is fabricated by solidifying, washing, and drying the liquid crystal polymer dissolved in sulfuric acid as a solvent after die casting, a solvent is required for extrusion, and an additional drying process is necessary to remove the solvent after casting.

[0006] In addition, there is a method to produce a liquid crystal polymer film with improved surface smoothness by extruding a molten liquid crystal polymer resin between heat-resistant synthetic resin films to form a laminate, and then peeling off the heat-resistant synthetic resin to improve the surface uniformity of the liquid crystal polymer film; however, this method requires an additional heat-resistant synthetic resin film and an additional peeling process to peel off the heat-resistant synthetic resin after forming the laminate. The problem to be solved

[0008] The present invention is intended to provide a liquid crystal polymer composition and a liquid crystal polymer film having low dielectric constant and dielectric loss tangent while having improved surface smoothness. means of solving the problem

[0010] Hereinafter, a liquid crystal polymer composition and a liquid crystal polymer film according to an embodiment of the present invention will be described.

[0012] Unless otherwise defined in this specification, all technical and scientific terms have the same meaning as generally understood by those skilled in the art to which the invention pertains. The terms used in the description of the invention are merely for the purpose of effectively describing specific embodiments and are not intended to limit the invention.

[0013] The singular forms used in this specification include plural forms unless the phrases clearly indicate otherwise.

[0014] As used in this specification, the meaning of 'includes' specifies certain characteristics, regions, integers, steps, actions, elements, and / or components, and does not exclude the existence or addition of other specific characteristics, regions, integers, steps, actions, elements, components, and / or groups.

[0015] The present invention is capable of various modifications and may take various forms, and specific embodiments are illustrated and described in detail below. However, this is not intended to limit the invention to the specific disclosed forms, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0016] In this specification, where the positional relationship between two parts is described, for example, using expressions such as 'on', 'on the upper part', 'on the lower part', 'next to', etc., one or more other parts may be located between the two parts unless expressions such as 'immediately' or 'directly' are used.

[0017] In this specification, when temporal sequences are described, for example, using expressions such as ‘after,’ ‘following,’ ‘next,’ or ‘before,’ cases that are not continuous may be included unless expressions such as ‘immediately’ or ‘directly’ are used.

[0018] In this specification, the term 'at least one' should be understood to include all combinations that can be presented from one or more related items.

[0020] According to one embodiment of the invention, a liquid crystal polymer composition is provided comprising silica microparticles having an average particle size of 1.0 μm or more and a surface modified to be hydrophobic, and a liquid crystal polymer resin.

[0021] As a result of the inventors' continued research, it was confirmed that when a liquid crystal polymer film is manufactured using a liquid crystal polymer composition comprising a liquid crystal polymer resin and silica particles whose surfaces are modified to be hydrophobic, the liquid crystal polymer resin is prevented from forming a liquid crystal structure in a molten state, thereby mitigating surface non-uniformity and resulting in excellent surface smoothness, while the dielectric constant and dielectric loss tangent of the film are also low, thus providing excellent insulation.

[0022] Conventionally, when a film is formed using only a liquid crystal polymer resin, liquid crystals are formed in the molten state of the liquid crystal polymer resin, resulting in an uneven surface of the film. Although silica particles were added to inhibit this liquid crystal formation, the silanol groups (Si-OH) on the surface of the silica particles caused poor compatibility with the liquid crystal polymer resin, leading to clumping of the silica particles during the mixing process of the composition and further deterioration of the surface smoothness.

[0023] However, the liquid crystal polymer composition according to the above embodiment includes silica microparticles whose surface is modified to be hydrophobic, and thus has high compatibility with the liquid crystal polymer resin and can improve the smoothness of the film surface by preventing the formation of liquid crystals in the molten state of the liquid crystal polymer resin.

[0024] In addition, when manufacturing a liquid crystal polymer film using the above liquid crystal polymer composition, unlike conventional technology, a smooth liquid crystal polymer film can be manufactured without an additional solvent drying process or a heat-resistant synthetic resin peeling process.

[0026] The above-mentioned silica microparticles with hydrophobic surfaces may have an average particle size of 1.0 μm or more, 1.5 μm or more, 2.0 μm or more, or 2.5 μm or more, or 8.0 μm or less, 7.0 μm or less, 6.0 μm or less, 5.0 μm or less, or 4.0 μm or less.

[0027] The average particle size of the above-mentioned silica microparticles with hydrophobic surfaces can generally be determined by the laser diffraction method. Laser diffraction measures the particle size distribution from the intensity distribution pattern of light that is diffracted and scattered as irradiated laser light penetrates a dispersed silica particle sample. In the particle size distribution curve measured by the laser diffraction method, the median value at 50% of the volume accumulation is D 50 This is referred to as the average particle size.

[0028] In addition, the average particle size of the silica microparticles with hydrophobic surfaces corresponds to the average particle size of primary particles in which the silica microparticles are not aggregated with each other.

[0029] If the average particle size of the silica microparticles with hydrophobicity modified on the surface is excessively small, it is difficult to prevent liquid crystal formation in the molten state of the liquid crystal polymer resin, resulting in a problem where the manufactured film becomes non-uniform. If the average particle size of the silica microparticles with hydrophobicity modified on the surface is excessively large, irregularities are formed on the surface of the film, resulting in a problem where the surface of the film becomes non-uniform.

[0030] The shape of the above-mentioned silica microparticles with hydrophobic surfaces may be polyhedral, and such polyhedral silica microparticles have a larger number of faces compared to spherical ones, which increases the surface area and can improve the efficiency of preventing liquid crystal formation in the molten state of the liquid crystal polymer resin.

[0031] The above polyhedron may be, for example, a prism, a tetrahedron, a hexahedron, a cuboctahedron, a rhombic cuboctahedron, or a regular dodecahedron.

[0033] The above-mentioned silica microparticles with a hydrophobically modified surface may be modified with a hydrophobic surface modifier. As a result, the silica microparticles have high compatibility with the liquid crystal polymer resin, thereby preventing the problem of only the silica microparticles aggregating within the composition and preventing the formation of liquid crystals in the molten phase of the liquid crystal polymer resin.

[0034] The above hydrophobic surface modifier may include an organic silane compound, silicone oil, or a mixture thereof.

[0035] The above organic silane compound may be one or more selected from the group consisting of alkylchlorosilanes such as trimethylchlorosilane, hexaalkyldisilazanes such as hexamethyldisilazane, alkyltrialkoxysilanes, and trialkylalkoxysilanes.

[0036] The above silicone oil may be polydimethylsiloxane.

[0037] The above-mentioned surface-hydrophobic modified silica microparticles are modified by the hydrophobic surface modifier, and may include polysiloxanes such as alkyl having 1 to 10 carbon atoms and polydimethylsiloxane on the surface.

[0038] The above-mentioned silica microparticles with hydrophobically modified surfaces are not limited thereto, but include, for example, the SYLOPHOBIC series (100, 200, 702, 704, 507, etc.) manufactured by Fuji Silicia Co., Ltd., the Nipsil SS series (SS-10, SS-50, SS-70, SS-115, etc.) manufactured by Toso Silicia Co., Ltd., and the SIPERNAT D series (D 10, D 13, D17) manufactured by Evonik Co., Ltd.

[0039] The above-mentioned surface-hydrophobic modified silica microparticles have high compatibility with liquid crystal polymer resin, so the silica microparticles have low aggregation among themselves within the composition containing the liquid crystal polymer resin, and can prevent the formation of liquid crystals in the liquid crystal polymer resin, thereby increasing the smoothness of the film.

[0041] The above-mentioned silica microparticles with a surface modified to be hydrophobic may have a DBA (di-n-butylamine) adsorption amount of 200 meq / kg or less, 175 meq / kg or less, 130 meq / kg or less, 100 meq / kg or less, 70 meq / kg or less, or 1 meq / kg or more, 5 meq / kg or more.

[0042] The above-mentioned di-n-butylamine (DBA) is adsorbed onto the hydroxyl groups of the silanol groups on the surface of the silica particles. In the case of silica microparticles that are not hydrophobically modified, the amount of DBA adsorbed is large, whereas in the case of silica microparticles with hydrophobically modified surfaces, the amount of DBA adsorbed may be small because the silanol groups are substituted with hydrophobic groups.

[0043] Accordingly, if the amount of DBA (di-n-butylamine) adsorbed by the above-mentioned surface-modified silica microparticles is excessively large, aggregation between silica microparticles within the composition may occur, which may reduce the smoothness of the manufactured film.

[0045] The content of silica particles with a surface modified to be hydrophobic, included in the liquid crystal polymer composition according to the above embodiment, may be 0.5 wt% or more, 0.7 wt% or more, 0.9 wt% or more, 1.0 wt% or more, 3.0 wt% or more, or 20 wt% or less, 15 wt% or less, 13 wt% or less, or 10 wt% or less, based on 100 wt% of the composition.

[0046] If the content of silica particles with a surface modified to be hydrophobic is high in the above composition, the dielectric properties of the liquid crystal polymer film produced may be degraded due to the excessive amount of particles, and if the content of the particles is excessively low, the film surface may not appear uniform.

[0048] The liquid crystal polymer resin included in the liquid crystal polymer composition according to the above embodiment may be a liquid crystal polymer capable of melt molding (or a polymer capable of forming an optically anisotropic molten phase), and the thermoplastic liquid crystal polymer may be a liquid crystal polymer capable of melt molding, and although its chemical composition is not particularly limited, for example, a thermoplastic liquid crystal polyester, or a thermoplastic liquid crystal polyesteramide in which an amide bond is introduced therein.

[0049] In addition, the liquid crystal polymer resin may be a polymer in which isocyanate-derived bonds, such as imide bonds, carbonate bonds, carbodiimide bonds, or isocyanurate bonds, are additionally introduced to an aromatic polyester or aromatic polyesteramide.

[0050] For example, the thermoplastic liquid crystal polyester may be prepared primarily from aromatic hydroxycarboxylic acids, aromatic dihydroxy, aromatic dicarboxylic acids, aromatic diamines, aromatic hydroxyamines and / or aromatic aminocarboxylic acid monomers.

[0051] The above aromatic hydroxycarboxylic acid monomers are not limited thereto, but may be, for example, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 5-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 4-(4-hydroxyphenyl)benzoic acid or 4-(3-hydroxyphenyl)benzoic acid.

[0052] The above aromatic dihydroxy monomers are not limited thereto, but may be, for example, 1,4-dihydroxybenzene, 1,3-dihydroxybenzene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-naphthalene dicarboxylic acid, 1,6-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-dihydroxybiphenyl or 4,4'-dihydroxybiphenyl ether, etc.

[0053] The above aromatic dicarboxylic acid monomer is not limited thereto, but may be, for example, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-4,4'-dicarboxylic acid or 4,4'-dicarboxydiphenyl ether, etc.

[0054] The monomer of the above aromatic diamine monomer is not limited thereto, but may be, for example, 1,4-diaminobenzene, 1,3-diaminobenzene, 1,5-diaminonaphthalene or 1,8-diaminonaphthalene.

[0055] The above aromatic hydroxyamine monomers are not limited thereto, but may be, for example, 4-aminophenol, 3-aminophenol, 4-amino-1-naphthol, 5-amino-1-naphthol, 6-amino-2-naphthol, or 4-amino-4'-hydroxybiphenyl, etc.

[0056] The above aromatic aminocarboxylic acid monomer is not limited thereto, but may be, for example, 4-aminobenzoic acid, 3-aminobenzoic acid, or 6-amino-2-naphthoic acid.

[0057] The above thermoplastic liquid crystal polyester is not limited thereto, but may be, for example, Type I composed of 4-hydroxybenzoic acid, terephthalic acid, and 4,4'-dihydroxybiphenyl, Type II composed of 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, and Type III composed of 4-hydroxybenzoic acid, terephthalic acid, and ethylene glycol.

[0058] In addition, representative commercial products currently on the market include Type I, Sumitomo Chemical’s Sumika Super and Solvay’s Zydar; Type II, Celanese’s Vectra; and Type III, Unitica’s Rodrun or Mitsubishi Engineering Plastics’ Novaculate.

[0060] According to another embodiment of the invention, a liquid crystal polymer film comprising silica microparticles having an average particle size of 1.0 μm or more and a surface modified to be hydrophobic, and a liquid crystal polymer resin is provided.

[0061] The liquid crystal polymer film described above includes silica microparticles with an average particle size of 1.0 μm or more and a surface modified to be hydrophobic, together with the liquid crystal polymer resin, thereby resolving the problem of the film surface becoming non-uniform in the past, and having excellent insulation properties with low dielectric constant and dielectric loss tangent, while also having excellent surface smoothness.

[0062] Details regarding the DBA adsorption amount of the above-mentioned surface-modified silica microparticles, the hydrophobic surface modifier, and the content thereof are as described above with respect to the liquid crystal polymer resin. Furthermore, details regarding the above-mentioned liquid crystal polymer resin are also as described above with respect to the liquid crystal polymer resin.

[0064] The liquid crystal polymer film described above can be manufactured from a mixed pellet by mixing a composition comprising the liquid crystal polymer resin and silica microparticles whose surfaces are modified to be hydrophobic, kneading the mixture using an extruder, forming a strand using a die having a plurality of through holes, and then cutting. For example, the mixed pellet may be used alone in a film-making extruder, or a liquid crystal polymer resin identical to or different from the liquid crystal polymer resin may be added to manufacture the liquid crystal polymer film. The die may be a T-shaped die or a circular die.

[0065] In addition, a liquid crystal polymer film can be manufactured by directly feeding a composition comprising the liquid crystal polymer resin and the silica microparticles whose surface has been modified to be hydrophobic into a film-making extruder without the above-mentioned mixed pellet production.

[0066] Meanwhile, the extruded liquid crystal polymer film can be stretched as needed. Stretching methods may include uniaxial stretching, biaxial stretching, inflation, laminate stacking stretching, etc.

[0067] In addition, a laminate can be formed by bonding another thermoplastic polymer film simultaneously with the formation of the liquid crystal polymer film at the die slit. That is, a co-extruded film in which a liquid crystal polymer layer and another thermoplastic polymer layer are laminated can be produced using a plurality of extruders and dies. The other thermoplastic polymer may be a polyolefin such as polyethylene, polypropylene, or ethylene-α-olefin copolymer; a polystyrene; a polycarbonate; a polyester such as polyethylene terephthalate or polybutylene terephthalate; a polyacetal; a polyamide; a polyphenylene ether; a polyethersulfone; an ethylene-vinyl acetate copolymer; a polyvinyl chloride; a polyvinylidene chloride; a polyphenylene sulfide; a fluoropolymer, etc.

[0068] In addition, the liquid crystal polymer film may be subjected to surface treatment to improve other physical properties depending on the required purpose. For example, this may include plasma surface treatment, corona discharge surface treatment, deposition, sputtering, solvent immersion treatment, etc.

[0070] According to the other embodiment above, the liquid crystal polymer film may have an arithmetic mean illuminance of at least one surface of 50 nm or more, 60 nm or more, 70 nm or more, or 1000 nm or less, 950 nm or less, 920 nm or less, or 900 nm or less. Such arithmetic mean illuminance can be measured using a 3D Optical Profiler (Bruker, NPFLEX) instrument.

[0071] In addition, the liquid crystal polymer film may have a dielectric constant measured in a microwave molecular orientation system of 0.1 or more, 0.2 or more, 0.3 or more, or 5.0 or less, 4.0 or less, or 3.5 or less.

[0072] In addition, the liquid crystal polymer film may have a dielectric loss tangent measured in a microwave molecular orientation system of 0.010 or less, 0.005 or less, or 0.003 or less.

[0074] A liquid crystal polymer film according to the above other embodiment may be applied to a circuit board. For example, the circuit board may include the liquid crystal polymer film and a conductive circuit layer formed on one surface of the liquid crystal polymer film.

[0075] The formation of the above-mentioned conductive circuit can be carried out according to known methods, for example, (a) a method of forming a conductive circuit by laminating a liquid crystal polymer film and a metal layer by thermal compression and then performing an etching treatment, etc., and (b) a method of forming a conductive layer on the surface of a liquid crystal polymer film by a vapor phase method such as sputtering, ion plating, or vacuum deposition, or by a wet plating method to form a conductive circuit.

[0076] The above circuit board may be a single-layer circuit board having a single metal layer (or conductive circuit layer), but in order to satisfy the requirement for high functionality of the circuit board, it may be a multi-layer circuit board having a plurality of metal layers (or conductive pattern layers) (e.g., a two-layer circuit board, a three-layer circuit board, a four-layer circuit board, etc.). In this case, in the circuit board, the patterned metal layer may be used as a signal line or ground plane line of a predetermined pattern as needed.

[0077] Since the above circuit board has a stable dielectric constant before and after heating even in the high-frequency region, and the above liquid crystal polymer film also has low dielectric properties, it can be used as a high-frequency circuit board. The high-frequency circuit board may not only consist of a circuit that simply transmits high-frequency signals, but may also include a circuit in which a transmission path that transmits signals other than high-frequency signals is installed on the same plane, such as a transmission path that converts a high-frequency signal into a low-frequency signal and outputs the generated low-frequency signal externally, or a transmission path for supplying power for driving high-frequency compatible components.

[0078] Examples of such transmission lines include various known or commonly used transmission lines, such as coaxial lines, strip lines, microstrip lines, coplanar lines, and parallel lines. Effects of the invention

[0080] The liquid crystal polymer composition according to the present invention and the liquid crystal polymer film prepared therefrom have low dielectric constant and dielectric loss tangent, and can exhibit excellent film surface smoothness by preventing liquid crystal formation when the liquid crystal polymer resin is melted. Brief explanation of the drawing

[0082] Figure 1 is a photograph showing the surface appearance of the liquid crystal polymer film of Example 1. Figure 2 is a photograph of the surface appearance of the liquid crystal polymer film of Comparative Example 1. Figure 3 is a photograph of the surface appearance of the liquid crystal polymer film of Comparative Example 2. Specific details for implementing the invention

[0083] Preferred embodiments are presented below to aid in understanding the invention. However, the following embodiments are merely illustrative of the invention and do not limit the invention to these embodiments.

[0085] <Preparation Example>

[0086] Preparation Example 1

[0087] A liquid crystal polymer composition was prepared by mixing 90 wt% of thermoplastic liquid crystal polyester pellets (CX-2199, ENEOS Liquid Crystal Co., Ltd.) and 10 wt% of silica microparticles with a surface modified to be hydrophobic (Sylophobic 100, Fuji Silicia, average particle size: 2.7 μm, DBA value: 50 meq / kg). Subsequently, a mixed pellet (MB-A) in which silica particles and liquid crystal polyester resin were mixed was produced using a twin-screw extruder at a temperature of 295 ℃.

[0089] Preparation Examples 2 to 5

[0090] Each mixed pellet was prepared in the same manner as in Preparation Example 1, except that silica microparticles listed in Table 1 below were used instead of the silica microparticles of Preparation Example 1.

[0092] Mixed pellets Content of Liquid Crystal Polyester Resin (LCP) (weight %) silica microparticles type Content (weight %) Preparation Example 1 MB-A 90 Particle A 10 Preparation Example 2 MB-B 90 Particle B 10 Preparation Example 3 MB-C 90 Particle C 10 Preparation Example 4 MB-D 90 Particle D 10 Preparation Example 5 MB-E 90 Particle E 10

[0093] - Particle B: Surface-hydrophobic modified silica particles (Sylophobic 100, Fuji Silicia, average particle size: 3.9 µm, DBA value: 50 meq / kg)

[0094] - Particle C: Surface-hydrophobic modified silica particles (Sylophobic 507, Fuji Silicia, average particle size: 2.7 µm, DBA value: 175 meq / kg)

[0095] - Particle D: Silica particles (SILYSIA 310P, Fuji Silicia, average particle size: 2.7 µm, DBA value: 500 meq / kg)

[0096] - Particle E: Silica particles (SILYSIA 340, Fuji Silicia, average particle size: 3.9 µm, DBA value: 500 meq / kg)

[0098] <Examples and Comparative Examples: Preparation of Liquid Crystal Polymer Films>

[0099] Example 1

[0100] A liquid crystal polymer film was produced using a single-screw extruder (LE30-30 / CV, Labtec) with the mixed pellet (MB-A) of Preparation Example 1.

[0101] Specifically, the L / D of the uniaxial extruder was 30, the diameter was 30 mm, and a T-die was used. The slit spacing of the die was 0.5 mm, and the slit width was 300 mm. In addition, the extruder temperature was set to 295 ℃, the die temperature was set to 295 ℃, and the screw speed was set to 60 rpm to produce a liquid crystal polymer film with a thickness of 50 μm.

[0103] Example 2

[0104] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 50 wt% of the mixed pellet (MB-A) of Preparation Example 1 and 50 wt% of the thermoplastic liquid crystal polyester pellet (CX-2199, ENEOS Liquid Crystal) were used instead of 100 wt% of the mixed pellet (MB-A) of Preparation Example 1.

[0106] Example 3

[0107] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 10 wt% of the mixed pellet (MB-A) of Preparation Example 1 and 90 wt% of the thermoplastic liquid crystal polyester pellet (CX-2199, ENEOS Liquid Crystal) were used instead of 100 wt% of the mixed pellet (MB-A) of Preparation Example 1.

[0109] Example 4

[0110] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 100% by weight of the mixed pellet (MB-B) of Preparation Example 2 was used instead of 100% by weight of the mixed pellet (MB-A) of Preparation Example 1.

[0112] Example 5

[0113] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 50 wt% of the mixed pellet (MB-B) of Preparation Example 2 and 50 wt% of the thermoplastic liquid crystal polyester pellet (CX-2199, ENEOS Liquid Crystal) were used instead of 100 wt% of the mixed pellet (MB-A) of Preparation Example 1.

[0115] Example 6

[0116] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 10 wt% of the mixed pellet (MB-B) of Preparation Example 2 and 90 wt% of the thermoplastic liquid crystal polyester pellet (CX-2199, ENEOS Liquid Crystal) were used instead of 100 wt% of the mixed pellet (MB-A) of Preparation Example 1.

[0118] Example 7

[0119] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 100% by weight of the mixed pellet (MB-C) of Preparation Example 3 was used instead of 100% by weight of the mixed pellet (MB-A) of Preparation Example 1.

[0121] Example 8

[0122] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 50 wt% of the mixed pellet (MB-C) of Preparation Example 3 and 50 wt% of the thermoplastic liquid crystal polyester pellet (CX-2199, ENEOS Liquid Crystal) were used instead of 100 wt% of the mixed pellet (MB-A) of Preparation Example 1.

[0124] Example 9

[0125] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 10 wt% of the mixed pellet (MB-C) of Preparation Example 3 and 90 wt% of the thermoplastic liquid crystal polyester pellet (CX-2199, ENEOS Liquid Crystal) were used instead of 100 wt% of the mixed pellet (MB-A) of Preparation Example 1.

[0127] Comparative Example 1

[0128] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 100 wt% of thermoplastic liquid crystal polyester pellets (CX-2199, ENEOS Liquid Crystal) were used instead of 100 wt% of the mixed pellets (MB-A) of Preparation Example 1.

[0130] Comparative Example 2

[0131] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 100% by weight of the mixed pellet (MB-D) of Preparation Example 4 was used instead of 100% by weight of the mixed pellet (MB-A) of Preparation Example 1.

[0133] Comparative Example 3

[0134] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 50 wt% of the mixed pellet (MB-D) of Preparation Example 4 and 50 wt% of the thermoplastic liquid crystal polyester pellet (CX-2199, ENEOS Liquid Crystal) were used instead of 100 wt% of the mixed pellet (MB-A) of Preparation Example 1.

[0136] Comparative Example 4

[0137] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 100% by weight of the mixed pellet (MB-E) of Preparation Example 5 was used instead of 100% by weight of the mixed pellet (MB-A) of Preparation Example 1.

[0139] Comparative Example 5

[0140] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 50 wt% of the mixed pellet (MB-E) of Preparation Example 5 and 50 wt% of the thermoplastic liquid crystal polyester pellet (CX-2199, ENEOS Liquid Crystal) were used instead of 100 wt% of the mixed pellet (MB-A) of Preparation Example 1.

[0142] Comparative Example 6

[0143] A liquid crystal polymer film was prepared in the same manner as in Example 1, except that 1 wt% of the mixed pellet (MB-A) of Preparation Example 1 and 99 wt% of the thermoplastic liquid crystal polyester pellet (CX-2199, ENEOS Liquid Crystal) were used instead of 100 wt% of the mixed pellet (MB-A) of Preparation Example 1.

[0145] <Test Example>

[0146] 1. Measurement of dielectric constant and dielectric loss tangent

[0147] The dielectric constant and dielectric loss tangent of the liquid crystal polymer films of the examples and comparative examples were measured using a microwave molecular orientation analyzer (MOA-7015, OZ Scientific Instruments), and the results are shown in Table 2 below. The measurements were taken at a frequency of 15 GHz.

[0149] 2. Film Appearance Evaluation

[0150] The surface appearance of the liquid crystal polymer films of the examples and comparative examples was observed using an optical microscope (Olympus DSX500). Specifically, the surface was observed in a bright field (BF) at a total magnification of 69x with a size of 3989 μm in length and 3989 μm in width. The evaluation criteria are as follows, and the results are shown in Table 2 below.

[0151] Meanwhile, FIG. 1 is a photograph of the surface appearance of the film of Example 1, FIG. 2 is a photograph of the surface appearance of the film of Comparative Example 1, and FIG. 3 is a photograph of the surface appearance of Comparative Example 2.

[0152] <Evaluation Criteria>

[0153] - Good: The film surface is non-flexible and no clumping was detected.

[0154] - Defective: Curvature on the film surface or clumping is found

[0156] 3. Surface roughness measurement

[0157] The surface roughness of the liquid crystal polymer films of the examples and comparative examples was measured using a 3D Optical Profiler (Bruker, NPFLEX) to determine the arithmetic mean surface roughness. Specifically, in vertical scanning interferometry (VSI) mode, the microscope magnification was set to 2.5 to measure a surface image with dimensions of 4000 μm vertically and 4000 μm horizontally, and then the arithmetic mean surface roughness was calculated with a cut-off of 800 μm. The results are shown in Table 2 below.

[0159] Dielectric constant (Dk) Genetic tangent (Df) Film appearance Surface roughness (nm) Example 1 3.2 0.002 Good 453 Example 2 3.2 0.001 Good 653 Example 3 3.2 0.001 Good 896 Example 4 3.3 0.002 Good 459 Example 5 3.3 0.001 Good 512 Example 6 3.3 0.001 Good 876 Example 7 3.3 0.002 Good 478 Example 8 3.3 0.001 Good 701 Example 9 3.3 0.001 Good 914 Comparative Example 1 3.3 0.001 error 1185 Comparative Example 2 3.1 0.004 error 2888 Comparative Example 3 3.1 0.002 error 2780 Comparative Example 4 3.2 0.003 error 2541 Comparative Example 5 3.2 0.002 error 2385 Comparative Example 6 3.3 0.001 error 1074

[0160] Referring to Table 2 above, it was confirmed that the liquid crystal polymer film of the example contains hydrophobically modified silica microparticles, and has a low dielectric constant and dielectric contact, a uniform surface, and a low arithmetic mean roughness of the surface. On the other hand, it was confirmed that the liquid crystal polymer film of the comparative example has a non-uniform surface and a high arithmetic mean roughness of the surface.

Claims

Claim 1 A liquid crystal polymer composition comprising: silica microparticles having an average particle size of 1.5 μm or more and 8.0 μm or less, with a surface modified to be hydrophobic; and a liquid crystal polymer resin. Claim 2 In claim 1, the above-mentioned surface-hydrophobic modified silica microparticles are a liquid crystal polymer composition modified with a hydrophobic surface modifier. Claim 3 In paragraph 2, the hydrophobic surface modifier comprises an organic silane compound, silicone oil, or a mixture thereof, in a liquid crystal polymer composition. Claim 4 In claim 1, the above-mentioned surface-modified silica microparticles are a liquid crystal polymer composition having a DBA (di-n-butylamine) adsorption amount of 200 meq / kg or less. Claim 5 In claim 1, the liquid crystal polymer resin is a thermoplastic liquid crystal polyester, a liquid crystal polymer composition. Claim 6 A liquid crystal polymer composition according to claim 1, wherein the content of silica particles with a surface modified to be hydrophobic is 0.5 to 20 weight% with respect to 100 weight% of the composition. Claim 7 A liquid crystal polymer film comprising: silica microparticles having an average particle size of 1.5 μm or more and 8.0 μm or less, with a surface modified to be hydrophobic; and a liquid crystal polymer resin. Claim 8 In claim 7, the above-mentioned surface-hydrophobic modified silica microparticles are a liquid crystal polymer film modified with a hydrophobic surface modifier. Claim 9 In claim 8, the above-mentioned hydrophobic surface modifier comprises an organic silane compound, silicone oil, or a mixture thereof, in a liquid crystal polymer film. Claim 10 In claim 7, the above-mentioned surface-hydrophobic silica microparticles are a liquid crystal polymer film having a DBA (di-n-butylamine) adsorption amount of 200 meq / kg or less. Claim 11 In claim 7, the liquid crystal polymer resin is a thermoplastic liquid crystal polyester, and the liquid crystal polymer film. Claim 12 A liquid crystal polymer film according to claim 7, wherein the content of silica particles whose surface is modified to be hydrophobic is 0.5 to 20 weight% with respect to 100 weight% of the film. Claim 13 A liquid crystal polymer film according to claim 7, wherein the arithmetic mean roughness of at least one surface of the liquid crystal polymer film is 50 to 1000 nm.

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