WO2023075316A1 - Liquid crystal polymer composition and molded article produced therefrom - Google Patents

Abstract

A liquid crystal polymer composition of the present invention comprises: about 100 parts by weight of a liquid crystal polymer; about 30 to about 140 parts by weight of glass fiber; about 0.2 to about 6 parts by weight of carbon fiber; and about 0.2 to about 10 parts by weight of graphite, wherein the weight ratio of the carbon fiber and the graphite is from about 1:1 to about 1:15. The liquid crystal polymer composition has excellent stiffness, impact resistance, etc., and has high dielectric constant and low dielectric loss characteristics.

Description

Liquid crystal polymer composition and molded article produced therefrom

The present invention relates to a liquid crystal polymer composition and a molded article made therefrom. More specifically, the present invention relates to a liquid crystal polymer composition having excellent rigidity, impact resistance, etc., high dielectric constant and low dielectric loss characteristics, and a molded article manufactured therefrom.

Recently, as the mobile environment changes to apply 5G networks that require high-frequency communication, it is essential to apply multiple antennas inside mobile devices, and miniaturization of antennas is required to minimize radio interference by increasing the degree of integration of antennas. It is becoming. In accordance with the miniaturization of antennas, the application of materials having a high permittivity and minimizing dielectric loss is required, and efforts are being made to secure smooth communication performance through this.

Thermoplastic resin compositions including polycarbonate resins, polyester resins, etc., which are currently generally applied, have a dielectric constant as low as 3 to 4, and may be accompanied by a high dielectric loss factor. In order to overcome this, carbon black, titanate (TiO ₂ ), carbon fiber (CaSiO ₃ ), etc., which can express high dielectric properties, are applied as fillers, but there is a limit to lowering the dielectric loss rate, and mechanical There is a risk that physical properties, etc. may deteriorate.

Therefore, it is necessary to develop a liquid crystal polymer composition having excellent stiffness, impact resistance, and high dielectric constant and low dielectric loss characteristics.

The background art of the present invention is disclosed in US Patent Publication No. US 2021/0032461 and the like.

An object of the present invention is to provide a liquid crystal polymer composition having excellent stiffness, impact resistance, and the like, and having high dielectric constant and low dielectric loss characteristics.

Another object of the present invention is to provide a molded article formed from the liquid crystal polymer composition.

The above and other objects of the present invention can all be achieved by the present invention described below.

1. One aspect of the present invention relates to a liquid crystal polymer composition. The liquid crystal polymer composition may include about 100 parts by weight of the liquid crystal polymer; about 30 to about 140 parts by weight of glass fibers; about 0.2 to about 6 parts by weight of carbon fiber; and about 0.2 to about 10 parts by weight of graphite, wherein the weight ratio of the carbon fibers to the graphite is about 1:1 to about 1:15.

2. In the first embodiment, the liquid crystal polymer may have a crystalline melting point of about 280 to about 360°C.

3. In the embodiment 1 or 2, the glass fiber may have a cross-sectional diameter of about 5 to about 20 μm and a length of about 200 to about 600 μm after processing.

4. In the embodiments 1 to 3, the carbon fiber may have a cross-sectional diameter of about 5 to about 10 μm and a length of about 400 to about 1,000 μm after processing.

5. In the above embodiments 1 to 4, the graphite may have an average particle size of about 5 to about 10 μm.

6. In embodiments 1 to 5, the weight ratio of the glass fiber to the carbon fiber may be about 1:0.005 to about 1:0.07.

7. In embodiments 1 to 6, the weight ratio of the glass fiber to the graphite may be about 1:0.02 to about 1:0.3.

8. In the embodiments 1 to 7, the liquid crystal polymer composition has a flexural modulus of about 80,000 to about 140,000 kgf/cm ² days of a 1/4" thick specimen measured at a speed of 2.8 mm/min according to ASTM D790 can

9. In the embodiments 1 to 8, the liquid crystal polymer composition may have a notched Izod impact strength of about 6 to about 20 kgf·cm/cm of a 1/8" thick specimen measured according to ASTM D256.

10. In the embodiments 1 to 9, the liquid crystal polymer composition is a 2.5 mm × 50 mm × 90 mm size specimen measured in the range of 5 to 67 GHz using a coaxial reflection resonator and a probe. A permittivity (ε′) corresponding to 28 GHz of may be about 6 to about 9.

11. In embodiments 1 to 10, the liquid crystal polymer composition is a 2.5 mm × 50 mm × 90 mm size specimen measured in the range of 5 to 67 GHz using a coaxial reflection resonator and a probe. A loss tangent corresponding to 28 GHz of may be about 0.02 or less.

12. Another aspect of the invention relates to molded articles. The molded article is characterized in that it is formed from the liquid crystal polymer composition according to any one of 1 to 11 above.

The present invention has the effect of providing a liquid crystal polymer composition having excellent rigidity, impact resistance, etc., high dielectric constant and low dielectric loss characteristics, and a molded article formed therefrom.

Hereinafter, the present invention will be described in detail as follows.

A liquid crystal polymer composition according to the present invention comprises (A) a liquid crystal polymer; (B) glass fibers; (C) carbon fiber; and (D) graphite.

In this specification, "a to b" representing a numerical range is defined as "≥a and ≤b".

(A) liquid crystal polymer

The liquid crystal polymer (LCP) according to one embodiment of the present invention exhibits an anisotropic melt phase, and liquid crystal polyesteramide, liquid crystal polyester, etc., called thermotropic liquid crystal polymers, may be used. Here, the anisotropic melt phase of the liquid crystal polymer can be confirmed by a method of a conventional polarization system using a light polarizer. For example, under a nitrogen atmosphere, a sample on a Leitz heating plate can be observed with a Leitz polarization microscope.

In embodiments, the liquid crystal polymer is aromatic oxycarbonyl, aromatic dicarbonyl, aromatic dioxy, aromatic aminooxy, aromatic aminocarbonyl, aromatic diamino, aromatic oxydicarbonyl, aliphatic dioxy, combinations thereof, and the like. Repeat units may be included.

In a specific embodiment, the liquid crystal polymer composed of the repeating units described above may include both providing and not providing an anisotropic melt phase, depending on the structural elements of the polymer and the ratio and arrangement distribution of the elements. The liquid crystal polymer used in the present invention exhibits an anisotropic melt phase.

In embodiments, examples of monomers providing aromatic oxycarbonyl repeat units include p-hydroxybenzoic acid, m-hydroxybenzoic acid, o-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 5-hydroxy- 2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 4'-hydroxybiphenyl-4-carboxylic acid, 3'-hydroxybiphenyl-4-carboxylic acid, 4'-hydroxybiphenyl -3-carboxylic acid and its alkyl-, alkoxy- or halogen-substituted derivatives, and ester-forming derivatives such as its acyl derivatives, ester derivatives and acyl halides. Among the above, p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are preferred with respect to easier control of properties and melting point of the resulting liquid crystal polymer.

In embodiments, examples of monomers providing aromatic dicarbonyl repeat units include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid acids, aromatic dicarboxylic acids such as 1,4-naphthalenedicarboxylic acid, 4,4′-dicarboxybiphenyl, and their alkyl-, alkoxy or halogen-substituted derivatives, and their ester derivatives, acid halides Ester-forming derivatives such as Among the above, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferred from the viewpoint of easier control of the mechanical properties, heat resistance, melting point and molding properties of the resulting liquid crystal polymer.

In embodiments, examples of monomers providing aromatic dioxy repeat units include hydroquinone, resorcines, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1, 4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl aromatic diols such as ethers, and ester-forming derivatives such as alkyl-, alkoxy- or halogen-substituted derivatives, and acyl derivatives thereof. Among the above, hydroquinone and 4,4'-dihydroxybiphenyl are preferred from the viewpoint of good reactivity during the polymerization process and good properties of the resulting liquid crystal polymer blend.

In embodiments, examples of monomers providing aromatic aminooxy repeat units include p-aminophenol, m-aminophenol, 4-amino-1-naphthol, 5-amino-1-naphthol, 8-amino-2-naphthol, Aromatic hydroxyamines such as 4-amino-4'-hydroxybiphenyl, and ester-forming derivatives such as alkyl-, alkoxy- or halogen-substituted derivatives and acyl derivatives thereof and amide-forming derivatives such as N-acyl derivatives thereof am.

In embodiments, examples of monomers providing aromatic diamino repeat units include aromatic diamines such as p-phenylenediamine, m-phenylenediamine, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, and alkyl- , alkoxy- or halogen-substituted derivatives, and amide-forming derivatives such as N-acyl derivatives thereof.

In embodiments, examples of monomers providing aromatic aminocarbonyl repeat units include aromatic aminocarboxylic acids such as p-aminobenzoic acid, m-aminobenzoic acid, 6-amino-2-naphthoic acid and alkyl-, alkoxy- or halogen -substituted derivatives, and ester-forming derivatives such as acyl derivatives, ester derivatives and acid halides thereof, and amide-forming derivatives such as N-acyl derivatives thereof.

In embodiments, examples of monomers providing aromatic oxydicarbonyl repeating units are hydroxyl, such as 3-hydroxy-2,7-naphthalenedicarboxylic acid, 4-hydroxyisophthalic acid, 5-hydroxyisophthalic acid. -aromatic dicarboxylic acids, and alkyl-, alkoxy- or halogen-substituted derivatives thereof, and ester-forming derivatives such as acyl derivatives, ester derivatives and acyl halides thereof.

In embodiments, examples of monomers providing aliphatic dioxy repeat units are ethylene glycol, aliphatic diols such as 1,4-butanediol, 1,6-hexanediol, and acyl derivatives thereof. In addition, the liquid crystal polymer having an aliphatic dioxy repeating unit is a polyester having an aliphatic dioxy repeating unit such as polyethylene terephthalate or polybutylene terephthalate, and the aromatic oxycarboxylic acid, aromatic dicarboxylic acid, aromatic diol, aromatic It can be obtained by reacting hydroxyamines, aromatic aminocarboxylic acids, aromatic diamines or acyl derivatives, ester derivatives or acid halides thereof.

In a specific embodiment, the liquid crystal polymer may have a thioester bond in the case where the bond does not impair the object of the present invention. Examples of monomers providing thioester linkages are mercapto-aromatic carboxylic acids, aromatic dithiols and hydroxy-aromatic thiols. Proportions of these additional monomers based on the total amount of monomers providing aromatic oxycarbonyl, aromatic di-carbonyl, aromatic dioxy, aromatic aminooxy, aromatic diamino, aromatic oxy di-carbonyl and aliphatic dioxy repeat units is preferably about 10 mol% or less.

Among the above, preferred liquid crystal polymers used in the present invention are those containing aromatic oxycarbonyl repeating units including 4-oxybenzoyl repeating units and/or 6-oxy-2-naphthoyl repeating units.

In embodiments, examples of preferred liquid crystal polymers containing 4-oxybenzoyl and/or 6-oxy-2-naphthoyl repeating units may include:

1) 4-hydroxybenzoic acid/6-hydroxy-2-naphthoic acid copolymer;

2) 4-hydroxybenzoic acid/terephthalic acid/4,4'-dihydroxybiphenyl copolymer;

3) 4-hydroxybenzoic acid/terephthalic acid/isophthalic acid/4,4'-dihydroxybiphenyl copolymer;

4) 4-hydroxybenzoic acid/terephthalic acid/isophthalic acid/4,4'-dihydroxybiphenyl/hydroquinone copolymer;

5) 4-hydroxybenzoic acid/terephthalic acid/hydroquinone copolymer;

6) 6-hydroxy-2-naphthoic acid/terephthalic acid/hydroquinone copolymer;

7) 4-hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/4,4'-dihydroxybiphenyl copolymer;

8) 6-hydroxy-2-naphthoic acid/terephthalic acid/4,4'-dihydroxybiphenyl copolymer;

9) 4-hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/hydroquinone copolymer;

10) 4-hydroxybenzoic acid/2,6-naphthalene dicarboxylic acid/4,4'-dihydroxybiphenyl copolymer;

11) 4-hydroxybenzoic acid/terephthalic acid/2,6-naphthalene dicarboxylic acid/hydroquinone copolymer;

12) 4-hydroxybenzoic acid/2,6-naphthalene dicarboxylic acid/hydroquinone copolymer;

13) 4-hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/2,6-naphthalene dicarboxylic acid/hydroquinone copolymer;

14) 4-hydroxybenzoic acid/terephthalic acid/2,6-naphthalene dicarboxylic acid/hydroquinone/4,4'-dihydroxybiphenyl copolymer;

15) 4-hydroxybenzoic acid/terephthalic acid/4-aminophenol copolymer;

16) 6-hydroxy-2-naphthoic acid/terephthalic acid/4-aminophenol copolymer;

17) 4-hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/4-aminophenol copolymer;

18) 4-hydroxybenzoic acid/terephthalic acid/4,4'-dihydroxybiphenyl/4-aminophenol copolymer;

19) 4-hydroxybenzoic acid/terephthalic acid/ethylene glycol copolymer;

20) 4-hydroxybenzoic acid/terephthalic acid/4,4'-dihydroxybiphenyl/ethylene glycol copolymer;

21) 4-hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/ethylene glycol copolymer, and

22) 4-hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/4,4′-dihydroxybiphenyl/ethylene glycol copolymer.

Among the above, the copolymers of 1), 9) and 13) are preferable from the viewpoint of moldability and mechanical properties of the polymer.

In a specific embodiment, the liquid crystal polymer may be a polymer blend including two or more liquid crystal polymers for the purpose of increasing fluidity of the polymer during molding.

In an embodiment, a method for preparing the liquid crystal polymer is not limited, and any method known in the art may be used. For example, conventional polycondensation methods such as a slurry polymerization method and melt acid decomposition in which a polymer is prepared to form ester and/or amide linkages in the above-described monomer elements can be used.

In an embodiment, the melt acid decomposition method is preferably used for preparing a liquid crystal polymer. In this method, the monomers are heated to form a molten solution and then the solution is reacted to form a molten polymer. The final step of this process may be performed under vacuum to facilitate the removal of volatile by-products such as acetic acid or water.

In an embodiment, the slurry polymerization process is characterized in that the monomers are reacted in a heat-exchange fluid to produce a solid state polymer in suspension in a heat-exchange liquid medium.

In a specific example, in either case of the melt acid decomposition method or the slurry polymerization method, the monomer to be polymerized may be in the form of a lower acyl derivative obtained by acylating a hydroxyl group and/or an amino group. A lower acyl group may have 2 to 5 carbon atoms, for example 2 to 3 carbon atoms. Preferably, acetylated monomers are used in the reaction.

In a specific embodiment, the lower acyl derivative of the monomer may be prepared by independently acylating the monomer beforehand or may be produced in situ by adding an acylating agent such as acetic anhydride to the monomer during preparation of the liquid crystal polymer.

In an embodiment, in either case of the melt acid decomposition method or the slurry polymerization method, a catalyst may be used in the reaction if desired.

In embodiments, examples of catalysts include organotin compounds such as dialkyl tin oxide (eg, dibutyl tin oxide) and diaryl tin oxide; antimony trioxide; titanium dioxide; organic titanium compounds such as alkoxy titanium silicates and titanium alkoxides; alkali or alkaline earth metal salts of carboxylic acids such as potassium acetate; salts of inorganic acids (eg K ₂ SO ₄ ); gaseous acid catalysts such as Lewis acids (eg, BF ₃ ) and hydrogen halides (eg, HCl).

In embodiments, when a catalyst is used, the amount of the catalyst added to the reaction based on the total amount of monomers may be about 10 to about 1,000 ppm, for example about 20 to about 200 ppm.

In embodiments, the liquid crystal polymer may be obtained from a reaction vessel in which it polymerizes in a molten state, and then processed to produce pellets, flakes, or powder.

In an embodiment, the liquid crystal polymer in the form of pellets, flakes or powder can be heated to a substantially solid state under vacuum or an inert gas atmosphere such as nitrogen or helium, if desired. The heat treatment temperature may be about 260 to about 350 °C, for example about 280 to about 320 °C.

In embodiments, the liquid crystal polymer may have a crystalline melting point (Tm) of about 280 to about 360° C. as determined by differential scanning calorimetry. The method for determining the crystalline melting point is as follows:

A differential scanning calorimeter (DSC) Exstar 6000 (Seiko Instruments Inc., Chiba, Japan) or a DSC apparatus of the same type is used. A liquid crystal polymer sample to be observed is heated from room temperature at a rate of 20 DEG C/min to measure an endothermic peak (Tm1). Thereafter, the sample is maintained at a temperature 20 to 50° C. higher than Tm1 for 10 minutes. The sample is then cooled to room temperature at a rate of 20°C/min and heated again at a rate of 20°C/min. The endothermic peak found in the final stage is recorded as the crystalline melting point (Tm) of the sample liquid crystal polymer.

(B) glass fiber

Glass fiber according to one embodiment of the present invention is applied together with carbon fiber and graphite to have high dielectric constant and low dielectric loss characteristics without deterioration of stiffness, impact resistance, etc. of the liquid crystal polymer composition, Phosphorus glass fibers can be used.

In embodiments, the glass fiber may be in the form of a fiber and may have cross sections of various shapes such as circular, elliptical, and rectangular. For example, it may be preferable in terms of mechanical properties to use fibrous glass fibers of circular and/or rectangular cross-section.

In embodiments, the circular cross-sectional glass fibers may have a cross-sectional diameter of about 5 to about 20 μm, for example about 8 to about 15 μm, as measured by a particle size measuring device (Malvern mastersizer 300), and a length before processing of about It may be 2 to about 5 mm, and the length after processing may be about 200 to about 600 μm, for example, about 300 to about 500 μm, and the glass fiber of the rectangular cross section has an aspect ratio of the cross section (long axis of the cross section / cross section The short diameter may be about 1.5 to about 10, the short diameter may be about 2 to about 10 μm, for example about 4 to about 8 μm, the length before processing may be about 2 to about 5 mm, and the length after processing may be about 200 to about 600 μm, for example about 300 to about 500 μm. Stiffness and processability of the liquid crystal polymer composition may be improved within the above range.

In a specific embodiment, the glass fiber may be treated with a conventional surface treatment agent. A silane-based compound, a urethane-based compound, an epoxy-based compound, etc. may be used as the surface treatment agent, but is not limited thereto.

In embodiments, the glass fiber may be included in an amount of about 30 to about 140 parts by weight, for example, about 40 to about 130 parts by weight, based on about 100 parts by weight of the liquid crystal polymer. If the content of the glass fibers is less than about 30 parts by weight based on about 100 parts by weight of the liquid crystal polymer, there is a concern that the stiffness and dielectric constant of the liquid crystal polymer composition may decrease, and if it exceeds about 140 parts by weight, the liquid crystal polymer composition There is a possibility that impact resistance, workability, appearance characteristics, etc. may deteriorate, and dielectric loss factor or the like may increase.

(C) carbon fiber

Carbon fiber according to one embodiment of the present invention is applied together with glass fiber and graphite to have high dielectric constant and low dielectric loss characteristics without deterioration of stiffness, impact resistance, etc. of the liquid crystal polymer composition, Phosphorus carbon fibers can be used.

In embodiments, the carbon fiber may have a cross-sectional diameter of about 5 to about 10 μm, for example, about 6 to about 9 μm, as measured by a particle size measuring device (Malvern mastersizer 300), and a length before processing of about 3 to about 7 mm, and may have a length of about 400 to about 1,000 μm after processing, for example about 500 to about 800 μm. Within the above range, the liquid crystal polymer composition may have excellent stiffness and appearance characteristics.

In embodiments, the carbon fibers may be included in an amount of about 0.2 to about 6 parts by weight, for example, about 0.5 to about 4 parts by weight, based on about 100 parts by weight of the liquid crystal polymer. If the content of the carbon fiber is less than about 0.2 parts by weight based on about 100 parts by weight of the liquid crystal polymer, the dielectric constant of the liquid crystal polymer composition may decrease, and if it exceeds about 6 parts by weight, the impact resistance of the liquid crystal polymer composition may be reduced. There is a possibility that the etc. may deteriorate and the dielectric loss factor or the like may increase.

In embodiments, the weight ratio (B:C) of the glass fibers (B) and the carbon fibers (C) may be about 1:0.005 to about 1:0.07, for example about 1:0.006 to about 1:0.05. . Within this range, the liquid crystal polymer composition may have excellent stiffness, impact resistance, and dielectric properties.

(D) graphite

Graphite according to one embodiment of the present invention is applied together with glass fibers and carbon fibers to have high dielectric constant and low dielectric loss characteristics without deterioration of stiffness, impact resistance, etc. of the liquid crystal polymer composition, Graphite can be used.

In embodiments, the graphite may have an average particle size of about 5 to about 10 μm, for example, about 7 to about 9 μm, as measured by a particle size measuring device (Malvern mastersizer 300). Within the above range, the liquid crystal polymer composition may have excellent appearance properties and dielectric properties.

In embodiments, the graphite may be included in an amount of about 0.2 to about 10 parts by weight, for example, about 3 to about 9 parts by weight, based on about 100 parts by weight of the liquid crystal polymer. If the graphite content is less than about 0.2 parts by weight based on about 100 parts by weight of the liquid crystal polymer, the dielectric constant of the liquid crystal polymer composition may be lowered, and if it exceeds about 10 parts by weight, the impact resistance of the liquid crystal polymer composition, etc. There is a risk of this deterioration.

In embodiments, the weight ratio (B:D) of the glass fiber (B) and the graphite (D) may be about 1:0.02 to about 1:0.3, for example about 1:0.03 to about 1:0.2. Within this range, the liquid crystal polymer composition may have excellent dielectric properties.

In embodiments, the weight ratio (C:D) of the carbon fiber (C) and the graphite (D) may be about 1:1 to about 1:15, for example about 1:1.5 to about 1:14.5. When the weight ratio of the carbon fiber to the graphite is less than about 1:1, there is a concern that the dielectric constant of the liquid crystal polymer composition may decrease, and when the weight ratio exceeds about 1:15, the impact resistance and dielectric constant of the liquid crystal polymer composition may decrease. there is

The liquid crystal polymer composition according to one embodiment of the present invention may further include additives included in conventional liquid crystal polymer compositions. Examples of the additives include antioxidants, anti-drip agents, lubricants, release agents, nucleating agents, antistatic agents, stabilizers, pigments, dyes, and mixtures thereof, but are not limited thereto. When using the additive, the amount thereof may be about 0.001 to about 40 parts by weight, for example, about 0.1 to about 10 parts by weight, based on about 100 parts by weight of the liquid crystal polymer.

The liquid crystal polymer composition according to one embodiment of the present invention may be in the form of pellets obtained by mixing the above components and melt-extruding them at about 330 to about 400° C., for example, about 340 to about 360° C., using a conventional twin-screw extruder. can

In embodiments, the liquid crystal polymer composition has a flexural modulus of about 80,000 to about 140,000 kgf/cm ² , for example about 81,000 to It may be about 135,000 kgf/cm ² .

In embodiments, the liquid crystal polymer composition has a notched Izod impact strength of about 6 to about 20 kgf cm / cm, for example, about 6.4 to about 15 kgf cm It can be /cm.

In an embodiment, the liquid crystal polymer composition has a size of 2.5 mm × 50 measured in the range of 5 to 67 GHz using a coaxial reflection resonator (ROHDE & SCHWARZ ZVA67) and a probe (SPEAG DAK-TL-P). The dielectric constant (ε') corresponding to 28 GHz of the mm × 90 mm size specimen may be about 6 to about 9, for example about 6 to about 8.5.

In an embodiment, the liquid crystal polymer composition has a size of 2.5 mm × 50 measured in the range of 5 to 67 GHz using a coaxial reflection resonator (ROHDE & SCHWARZ ZVA67) and a probe (SPEAG DAK-TL-P). The dielectric loss factor (loss tangent) corresponding to 28 GHz of the mm × 90 mm size specimen may be about 0.02 or less, for example, about 0.015 or less.

A molded article according to the present invention is formed from the liquid crystal polymer composition. The liquid crystal polymer composition may be manufactured in the form of pellets, and the manufactured pellets may be manufactured into various molded articles (products) through various molding methods such as injection molding, extrusion molding, vacuum molding, and casting molding. Such a molding method is well known to those skilled in the art to which the present invention belongs. The molded article has excellent stiffness, impact resistance, and the like, and has high permittivity and low dielectric loss characteristics, and is useful as exterior and interior materials for mobile and wearable devices.

Hereinafter, the present invention will be described in more detail through examples, but these examples are only for the purpose of explanation and should not be construed as limiting the present invention.

Example

Hereinafter, specifications of each component used in Examples and Comparative Examples are as follows.

(A) liquid crystal polymer

As the liquid crystal polymer, 4-hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/4,4'-dihydroxybiphenyl copolymer (manufacturer: Seyang Polymer, product name: G600BB) was used.

(B) glass fiber

Glass fiber (manufacturer: Saint Gobain, product name: EC10, cross-sectional diameter: 10 μm, length after processing: 400 μm) was used.

(C) carbon fiber

Carbon fiber (manufacturer: Toray, product name: T700, cross-sectional diameter: 8 μm, length after processing: 600 μm) was used.

(D) graphite

Graphite (manufacturer: Samjeong C&G, product name: DN8, average particle size: 8 μm) was used.

Examples 1 to 8 and Comparative Examples 1 to 8

After adding each of the components in an amount as shown in Tables 1 and 2 below, pellets were prepared by extruding at 360 ° C. For extrusion, a twin screw extruder with L/D = 44 and a diameter of 45 mm was used, and the pellets were dried at 80 ° C for more than 4 hours, and then injection molded in a 6 oz injection machine (molding temperature: 340 ° C, mold temperature: 80 ° C) Thus, specimens were prepared. The physical properties of the prepared specimens were evaluated by the following method, and the results are shown in Tables 1 and 2 below.

How to measure physical properties

(1) Flexural modulus (unit: kgf/cm ² ): According to ASTM D790, the flexural modulus of a 1/4" thick specimen was measured at a speed of 2.8 mm/min.

(2) Notched Izod impact strength (unit: kgf cm/cm): In accordance with ASTM D256, the notched Izod impact strength of a 1/8" thick specimen was measured.

(3) Permittivity: 2.5 mm × 50 mm × 90 mm in the range of 5 to 67 GHz using a coaxial reflection resonator (ZVA67 from ROHDE & SCHWARZ) and a probe (DAK-TL-P from SPEAG) The permittivity (ε') corresponding to 28 GHz of the specimen was measured.

(4) Dielectric loss factor: 2.5 mm × 50 mm × 90 mm in the range of 5 to 67 GHz using a coaxial reflection resonator (ZVA67 from ROHDE & SCHWARZ) and a probe (DAK-TL-P from SPEAG) The dielectric loss factor (loss tangent) corresponding to 28 GHz of the specimen was measured.

	Example
	One	2	3	4	5	6	7	8
(A) (parts by weight)	100	100	100	100	100	100	100	100
(B) (parts by weight)	40	81	130	81	81	81	81	81
(C) (parts by weight)	1.8	1.8	1.8	0.5	4	1.8	1.8	1.8
(D) (parts by weight)	7.2	7.2	7.2	7.2	7.2	3	5.4	9
Flexural modulus	81,000	115,000	135,000	111,000	118,000	115,000	113,000	108,000
Notched Izod Impact Strength	14.1	8.0	6.4	8.2	7.1	8.1	7.8	7.4
permittivity	6.60	7.09	7.30	7.20	7.00	6.02	6.71	8.05
dielectric loss factor	0.008	0.010	0.012	0.010	0.015	0.010	0.010	0.010

	comparative example
	One	2	3	4	5	6	7	8
(A) (parts by weight)	100	100	100	100	100	100	100	100
(B) (parts by weight)	20	150	81	81	81	81	81	81
(C) (parts by weight)	1.8	1.8	0.1	7	1.8	1.8	0.5	2
(D) (parts by weight)	7.2	7.2	7.2	7.2	0.1	11	10	One
Flexural modulus	59,000	145,000	115,000	118,000	111,000	102,000	101,000	112,000
Notched Izod Impact Strength	16.1	4.3	8.2	5.5	7.2	3.1	3.4	8.5
permittivity	5.9	9.2	5.8	7.8	4.9	9.0	6.7	4.5
dielectric loss factor	0.007	0.022	0.007	0.040	0.009	0.010	0.007	0.006

From the above results, it can be seen that the liquid crystal polymer composition of the present invention is excellent in stiffness (flexural modulus) and impact resistance (notched Izod impact strength), and has high dielectric constant and low dielectric loss characteristics.

On the other hand, in the case of Comparative Example 1 in which a small amount of glass fiber was applied, it can be seen that the stiffness, dielectric constant, etc. were reduced, and in the case of Comparative Example 2 in which an excessive amount of glass fiber was applied, impact resistance, low dielectric loss characteristics, workability, etc. were reduced. In the case of Comparative Example 3 in which a small amount of carbon fiber was applied, it can be seen that the dielectric constant and the like were lowered, and in the case of Comparative Example 4 in which an excessive amount of carbon fiber was applied, impact resistance and low dielectric loss characteristics were reduced. In addition, in the case of Comparative Example 5 in which a small amount of graphite was applied, it can be seen that the dielectric constant and the like were lowered, and in the case of Comparative Example 6 in which an excessive amount of graphite was applied, it was found that the impact resistance and the like were lowered, and the content of carbon fiber and graphite Even if it is included in the range of, when the weight ratio (C:D) of carbon fiber and graphite exceeds 1:15 (1:20) (Comparative Example 7), it can be seen that impact resistance, etc. is reduced, and less than 1:1 (1: 0.5) (Comparative Example 8), it can be seen that the permittivity and the like are lowered.

So far, the present invention has been looked at mainly through embodiments. Those skilled in the art to which the present invention pertains will be able to understand that the present invention may be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments are to be considered in an illustrative rather than a limiting sense. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the equivalent scope will be construed as being included in the present invention.

Claims (12)

1. about 100 parts by weight of a liquid crystal polymer;

   about 30 to about 140 parts by weight of glass fibers;

   about 0.2 to about 6 parts by weight of carbon fiber; and

   About 0.2 to about 10 parts by weight of graphite;

   The liquid crystal polymer composition, characterized in that the weight ratio of the carbon fiber and the graphite is about 1: 1 to about 1: 15.
2. The liquid crystal polymer composition according to claim 1, wherein the liquid crystal polymer has a crystalline melting point of about 280 to about 360°C.
3. The liquid crystal polymer composition according to claim 1 or 2, wherein the glass fiber has a cross-sectional diameter of about 5 to about 20 μm and a length of about 200 to about 600 μm after processing.
4. The liquid crystal polymer composition according to any one of claims 1 to 3, wherein the carbon fiber has a cross-sectional diameter of about 5 to about 10 μm and a length of about 400 to about 1,000 μm after processing.
5. The liquid crystal polymer composition according to any one of claims 1 to 4, wherein the graphite has an average particle size of about 5 to about 10 μm.
6. The liquid crystal polymer composition according to any one of claims 1 to 5, wherein the weight ratio of the glass fiber to the carbon fiber is about 1:0.005 to about 1:0.07.
7. The liquid crystal polymer composition according to any one of claims 1 to 6, wherein the weight ratio of the glass fiber and the graphite is from about 1:0.02 to about 1:0.3.
8. The method according to any one of claims 1 to 7, wherein the liquid crystal polymer composition has a flexural modulus of about 80,000 to about 140,000 kgf of a 1/4" thick specimen measured at a speed of 2.8 mm/min according to ASTM D790. /cm ² Liquid crystal polymer composition, characterized in that.
9. The method according to any one of claims 1 to 8, wherein the liquid crystal polymer composition has a notched Izod impact strength of about 6 to about 20 kgf cm/cm of a 1/8" thick specimen measured according to ASTM D256. A liquid crystal polymer composition characterized by
10. The method according to any one of claims 1 to 9, wherein the liquid crystal polymer composition has a thickness of 2.5 mm × 50 mm × 50 mm as measured in the range of 5 to 67 GHz using a coaxial reflection resonator and a probe. A liquid crystal polymer composition, characterized in that the dielectric constant (ε ') corresponding to 28 GHz of a 90 mm size specimen is about 6 to about 9.
11. The liquid crystal polymer composition according to any one of claims 1 to 10, using a coaxial reflection resonator and a probe, measured in the range of 5 to 67 GHz, 2.5 mm × 50 mm × A liquid crystal polymer composition characterized in that a loss tangent corresponding to 28 GHz of a 90 mm size specimen is about 0.02 or less.
12. A molded article formed from the liquid crystal polymer composition according to any one of claims 1 to 11.