Liquid crystal resin composition for planar connectors and planar connectors using the same.

Abstract

A liquid crystal resin composition with good flowability is provided, and a planar connector comprising the liquid crystal resin composition, wherein the liquid crystal resin composition enables the manufacture of a planar connector with excellent crack resistance, mechanical strength and dielectric properties. The planar connector liquid crystal resin composition of the present invention contains (A) a fully aromatic polyester, (B) a fibrous inorganic filler, and (C) an inorganic spherical hollow body. Component (A) contains constituent units (I) to (IV), and the content of each constituent unit relative to the total constituent unit is: (I): 40-75 mol%, (II): 0.5-7.5 mol%, (III): 8.5-30 mol%, (IV): 8.5-30 mol%. The weight-average fiber length of component (B) is 150-500 μm, and the content of each constituent unit relative to the total liquid crystal resin composition is: (A): 57-85 wt%, (B): 5-14 wt%, (C): 7.5-29 wt%, and the total of components (B) and (C): 15-43 wt%. Ar 1 and Ar 2 independently represent aryl groups.

Description

Technical Field

[0001] This invention relates to a liquid crystal resin composition for planar connectors and a planar connector using the same. Prior Technology

[0002] Liquid crystal resins, represented by liquid crystal polyester resins, offer a good balance between excellent mechanical strength, heat resistance, chemical resistance, and electrical properties, as well as excellent dimensional stability, making them widely used as high-performance engineering plastics. Furthermore, due to their excellent flowability, liquid crystal resins have historically been used as materials for various electronic components. In particular, with the increasing performance of electronic devices in recent years, there is a demand for molded products containing microstructures (such as planar connectors). To meet this demand, for example, Patent Document 1 proposes a planar connector molded from a composite resin composition consisting of a specific liquid crystal polymer, inorganic filler, and glass fiber. This connector exhibits excellent formability, flatness, warpage resistance, and heat resistance, and is less prone to cracking (also known as breakage) in areas such as the grid. [Previous Technical Documents] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2012-214652 Summary of the Invention

[0004] [The problem the invention aims to solve]

[0005] In recent years, with the transition from LTE to 5G, there has been a demand for improved computing power in communication terminals. Therefore, it is essential to enhance CPU performance to achieve high-speed computational processing. High-speed computational processing can be achieved, for example, by endowing the CPU with high-speed computational capabilities. A specific example is the Digital Signal Processor (DSP). A DSP is a computational processing device used for digital signal processing and is a type of CPU. Previously, to achieve high-speed processing of the numerous multiplication-accumulation operations used in signal processing, multiplication and addition functions were implemented using other hardware. However, with the increasing speed of CPU modules and the shift in development towards performing multiplication-accumulation operations directly on the CPU, DSPs began to be manufactured.

[0006] In CPU installation, a corresponding CPU socket is typically used. Depending on the shape of the CPU, the shape of the CPU socket tends to become more complex. Furthermore, to achieve high-speed computing, and in response to the increasing number of CPU pins and increased density, CPU sockets are increasingly featuring multi-pin designs and narrower pitch. Simultaneously, to reduce signal transmission losses caused by the CPU socket material, the material itself needs to have a low dielectric constant and a low dielectric loss tangent. Liquid crystal resin compositions are considered as alternative CPU socket materials. However, when using liquid crystal resin compositions to manufacture CPU sockets, the fluidity of the liquid crystal resin composition may decrease, or mechanical strength may decrease or crack after molding, depending on the complex shape of the CPU socket. Additionally, as mentioned above, it is desirable for the CPU socket material to have appropriate dielectric properties.

[0007] However, according to the inventors' research, conventional liquid crystal resin compositions have very high melt viscosity and poor flowability. Furthermore, even when using conventional liquid crystal resin compositions to manufacture planar connectors, such as CPU sockets, it is impossible to adequately suppress crack formation, reduce mechanical strength, or decrease dielectric properties. This invention was made to solve the above problems, and its object is to provide a liquid crystal resin composition with good flowability, and a planar connector comprising said liquid crystal resin composition, which enables the manufacture of planar connectors with excellent crack resistance, mechanical strength, and dielectric properties. [Solutions to the problem]

[0008] The inventors conducted extensive research to address the aforementioned problems. As a result, the invention, comprising a planar connector liquid crystal resin composition containing, in specified amounts, a fully aromatic polyester comprising a large amount of constituent units derived from 6-hydroxy-2-naphthoic acid, a fibrous inorganic filler with an average fiber length of 150-500 μm by weight, and an inorganic spherical hollow body, solves the aforementioned problems, thus completing the present invention. More specifically, the present invention provides the following invention.

[0009] (1) A liquid crystal resin composition comprising: (A) a fully aromatic polyester; (B) a fibrous inorganic filler; and (C) a planar connector liquid crystal resin composition with inorganic spherical hollow bodies. Among them, relative to the entire constituent unit, the aforementioned (A) fully aromatic polyester contains the following constituent units (I) to (IV), The content of constituent unit (I) is 40-75 mol%; the content of constituent unit (II) is 0.5-7.5 mol%; the content of constituent unit (III) is 8.5-30 mol%; and the content of constituent unit (IV) is 8.5-30 mol%. The aforementioned (B) fibrous inorganic filler has a weight-average fiber length of 150~500μm. Relative to the aforementioned liquid crystal resin composition as a whole, the content of the aforementioned (A) fully aromatic polyester is 57-85% by mass; the content of the aforementioned (B) fibrous inorganic filler is 5-14% by mass; the content of the aforementioned (C) inorganic spherical hollow body is 7.5-29% by mass; and the total content of the aforementioned (B) fibrous inorganic filler and the aforementioned (C) inorganic spherical hollow body is 15-43% by mass.

[0010] [Chemistry 1] (In the formula, Ar 1 and Ar 2 each independently represent aramid.)

[0011] (2) The liquid crystal resin composition as described in (1), wherein the aforementioned (B) fibrous inorganic filler is one or more selected from the group consisting of glass fibers and ground glass fibers.

[0012] (3) The liquid crystal resin composition as described in (1) or (2), wherein the aforementioned inorganic spherical hollow body (C) is a glass sphere.

[0013] (4) The liquid crystal resin composition described in any one of (1) to (3) has a relative permittivity of 3.4 or less at a measurement frequency of 5 GHz.

[0014] (5) A planar connector comprising a liquid crystal resin composition as described in any one of (1) to (4), having an outer frame portion and a lattice structure formed on the inner side of the outer frame portion, wherein the pitch interval of the lattice portion of the aforementioned lattice structure is 1.5 mm or less. [Invention Effects]

[0015] According to the present invention, a liquid crystal resin composition with good flowability and a planar connector comprising the liquid crystal resin composition can be provided, wherein the liquid crystal resin composition enables the manufacture of a planar connector with excellent crack resistance, mechanical strength and dielectric properties. Simple Explanation of the Diagram

[0016] Figure 1 shows a planar connector formed according to the embodiment, (a) is a plan view, and (b) is a right side view. The units for the values ​​in the figures are mm. Figure 2 shows the location of the gate of the planar connector formed according to the embodiment; (a) is a plan view, and (b) is a right side view. Furthermore, the units of the values ​​in the figures are mm. Figure 3 is a top view showing the cut-out position of the test piece used in the embodiment and comparative examples for evaluating dielectric properties in the flow right-angle direction. Figure 4 is a top view showing the cut-out position of the test piece used in the embodiment and comparative examples for evaluating dielectric properties in the flow direction. Implementation

[0017] The following describes embodiments of the present invention. However, the present invention is not limited to these embodiments.

[0018] <Liquid Crystal Resin Composition for Planar Connectors> The planar connector liquid crystal resin composition of the present invention comprises: (A) a fully aromatic polyester, (B) a fibrous inorganic filler, and (C) an inorganic spherical hollow body, wherein the weight average fiber length of the (B) fibrous inorganic filler is 150-500 μm.

[0019] [(A) Fully aromatic polyester] The liquid crystal resin composition of the present invention contains (A) a fully aromatic polyester. (A) the fully aromatic polyester can be used alone or in combination of two or more. (A) the fully aromatic polyester contains the following constituent units (I) to (IV). Relative to all constituent units, The content of constituent unit (I) is 40-75 mol%. The content of constituent unit (II) is 0.5~7.5 mol%. The content of constituent unit (III) is 8.5~30 mol%. The content of constituent unit (IV) is 8.5~30 mol.

[0020] [Chemistry 2] (In the formula, Ar 1 and Ar 2 each independently represent aramid.)

[0021] The constituent unit (I) is derived from 6-hydroxy-2-naphthoic acid (hereinafter also referred to as "HNA"). Component (A) contains 40 to 75 mol% of constituent unit (I) relative to all constituent units. If the content of constituent unit (I) is within the range described above, the dielectric properties, heat resistance, and manufacturability are readily improved. From the viewpoint of dielectric properties, heat resistance, and manufacturability, the content of constituent unit (I) relative to all constituent units is preferably 40 to 60 mol%, more preferably 45 to 60 mol%.

[0022] Constituent unit (II) is derived from 4-hydroxybenzoic acid (hereinafter also referred to as "HBA"). Component (A) contains 0.5 to 7.5 mol% of constituent unit (II) relative to all constituent units. If the content of constituent unit (II) is within the range described above, heat resistance and manufacturability are readily improved. From the viewpoint of heat resistance and manufacturability, the content of constituent unit (II) relative to all constituent units is preferably 1 to 6 mol%.

[0023] Constituent unit (III) is a unit derived from a dicarboxylic acid. Examples of Ar 1 include 1,2-phenylene, 1,3-phenylene, and 1,4-phenylene. From the viewpoint of heat resistance, constituent unit (III) is preferably derived from 1,4-phenylenedicarboxylic acid (hereinafter also referred to as "TA"). The content of constituent unit (III) relative to all constituent units is 8.5 to 30 mol%, preferably 17.5 to 30 mol.

[0024] The constituent unit (IV) is a constituent unit derived from a diol. Hydroquinone, dihydroxybiphenyl, etc., can be used as the diol; from the viewpoint of heat resistance, dihydroxybiphenyl, especially 4,4'-dihydroxybiphenyl (hereinafter also referred to as "BP"), is preferred. The content of the constituent unit (IV) relative to all constituent units is 8.5 to 30 mol%, preferably 17.5 to 30 mol%.

[0025] Because component (A) contains a specific amount of specific constituent units (I) to (IV) relative to all constituent units, it exhibits excellent dielectric properties, heat resistance, and manufacturability. Furthermore, component (A) preferably contains a total of 100 moles of constituent units (I) to (IV) relative to all constituent units.

[0026] Next, the method for manufacturing the fully aromatic polyester of the present invention will be described. The fully aromatic polyester of the present invention is polymerized using direct polymerization, transesterification, or the like. During polymerization, melt polymerization, solution polymerization, slurry polymerization, solid-state polymerization, or a combination of two or more thereof can be used. Preferably, melt polymerization or a combination of melt polymerization and solid-state polymerization can be used.

[0027] In this invention, during polymerization, acetic acid modifiers, terminally activated monomers such as acetic acid chloride compound derivatives, can be used on the monomers. Examples of acetic acid modifiers include fatty acid anhydrides such as acetic anhydride.

[0028] Various catalysts can be used during the polymerization of these materials. Representative catalysts include metal salt catalysts such as potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, antimony trioxide, and tris(2,4-pentanedionato)cobalt(III), as well as organic compound catalysts such as 1-methylimidazole and 4-dimethylaminopyridine.

[0029] For example, reaction conditions include a reaction temperature of 200–380 °C and a final pressure of 0.1–760 Torr (i.e., 13–101,080 Pa). Particularly in molten reactions, for example, the reaction temperature is 260–380 °C, preferably 300–360 °C, and the final pressure is 1–100 Torr (i.e., 133–13,300 Pa), more preferably 1–50 Torr (i.e., 133–6,670 Pa).

[0030] The reaction can be initiated by loading all the raw material monomers (HNA, HBA, TA, and BP), acetic acidifier, and catalyst into the same reaction vessel (one-stage reaction), or by acetic acidifying the hydroxyl groups of the raw material monomers HNA, HBA, and BP with the acetic acidifier and then reacting them with the carboxyl groups of TA (two-stage reaction).

[0031] After the melt polymerization reaches the specified temperature in the reaction system, the pressure is reduced to a specified level. Once the torque of the agitator reaches the specified value, an inert gas is introduced, and the pressure is increased from the reduced pressure state to the specified pressurized state, at which point the fully aromatic polyester is discharged from the reaction system.

[0032] The fully aromatic polyester produced by the above polymerization method can be further polymerized by solid-state polymerization under normal or reduced pressure in an inert gas atmosphere to increase its molecular weight. The preferred conditions for the solid-state polymerization reaction are a reaction temperature of 230-350°C, more preferably 260-330°C, and a final pressure of 10-760 Torr (i.e., 1,330-101,080 Pa).

[0033] Next, the properties of the fully aromatic polyester will be described. The fully aromatic polyester of this invention exhibits optical anisotropy when melted. The optical anisotropy of a resin when melted indicates that the resin is a liquid crystal resin. The fully aromatic polyester of this invention combines thermal stability and processability.

[0034] The anisotropy of melt can be confirmed using conventional polarization methods with crossed polarizers. More specifically, melt anisotropy can be confirmed by using a polarizing microscope manufactured by OLYMPUS, melting the sample on a heated stage manufactured by LINKAM, and observing it at 150x magnification under a nitrogen atmosphere. Fully aromatic polyesters are optically anisotropic, allowing light to pass through when inserted between crossed polarizers. If the sample is optically anisotropic, polarized light will pass through even in a state such as a molten, stationary liquid.

[0035] Because nematic aromatic polyesters exhibit a significant decrease in viscosity above their melting point, liquid crystallization at or above the melting point is generally used as an indicator of processability. From a heat resistance perspective, a higher melting point is better; however, considering the thermal degradation of aromatic polyesters during melt processing and the heating capacity of extruders, a melting point below 360°C is preferred. Furthermore, 300–360°C is more preferred, and 320–358°C is even more preferred.

[0036] At the film-forming temperature and shear rate of 1000 / second according to the present invention, the melt viscosity of the aforementioned fully aromatic polyester is preferably 500 Pa·s or less, more preferably 50 to 400 Pa·s, and even more preferably 100 to 300 Pa·s. When the melt viscosity is within the above range, the fully aromatic polyester itself or a composition containing the aforementioned fully aromatic polyester can easily ensure film-forming properties during extrusion. Furthermore, in this specification, the melt viscosity is defined as the value obtained according to ISO 11443.

[0037] The content of component (A) relative to the total liquid crystal resin composition is 57-85% by mass, preferably 59-83% by mass, and more preferably 62.5-77.5% by mass. If the content of component (A) is within the above range, a liquid crystal resin composition with excellent dielectric properties can be easily obtained.

[0038] (B) Fibrous inorganic filler If the liquid crystal resin composition of the present invention contains a fibrous inorganic filler, the crack resistance of the molded article made of the liquid crystal resin composition is easily improved, and the mechanical strength such as the flexural modulus is easily improved. One type of fibrous inorganic filler may be used alone, or two or more types may be used in combination.

[0039] The average fiber length of the fibrous inorganic filler is 150-500 μm, preferably 200-450 μm, and more preferably 250-400 μm. If the average fiber length is 150 μm or more, the crack resistance of the molded article made from the liquid crystal resin composition of the present invention is easily improved. If the average fiber length is 500 μm or less, the dielectric properties of the molded article made from the liquid crystal resin composition are easily improved. Furthermore, in this specification, the average fiber length of the fibrous inorganic filler is used as follows: 10 stereomicroscopic images of the fibrous inorganic filler are imported from a CCD camera to a PC, and the average fiber length of 100 fibrous inorganic fillers in each stereomicroscopic image, totaling 1000 fibrous inorganic fillers, is measured using an image processing method of an image measuring machine. The average fiber length of the fibrous inorganic filler in the liquid crystal resin composition was determined by applying the above method to the fibrous inorganic filler remaining after ashing by heating the liquid crystal resin composition at 600°C for 2 hours. Furthermore, in this specification, unless otherwise stated, the average fiber length refers to the weight-average fiber length.

[0040] There is no particular limitation on the fiber diameter of the fibrous inorganic filler material; for example, it can be less than 20 μm or 5~15 μm. Furthermore, in this specification, the fiber diameter of the fibrous inorganic filler is determined by averaging the fiber diameter values ​​of 30 fibrous inorganic fillers observed using a scanning electron microscope. The fiber diameter of the fibrous inorganic filler in the liquid crystal resin composition is determined by applying the above method to the fibrous inorganic filler remaining after ashing by heating the liquid crystal resin composition at 600°C for 2 hours.

[0041] Any fiber can be used, as long as it is a fibrous inorganic filler that satisfies the above-described shape. Examples of fibrous inorganic fillers include glass fiber, ground glass fiber, carbon fiber, asbestos fiber, silica fiber, silica-alumina fiber, zirconium dioxide fiber, boron nitride fiber, silica fiber, boron fiber, potassium titanate fiber, calcium silicate fiber (wollastonite), and inorganic fibrous materials such as fibrous materials of metals such as stainless steel, aluminum, titanium, copper, and brass. In this invention, from the viewpoint of crack resistance, at least one fibrous inorganic filler selected from the group consisting of glass fiber and ground glass fiber is preferred.

[0042] The content of component (B) relative to the total liquid crystal resin composition is 5 to 14% by mass, preferably 6 to 12.5% ​​by mass, and more preferably 7 to 10% by mass. If the content of component (B) is within the above range, the crack resistance and mechanical strength of the molded article made of the liquid crystal resin composition can be easily improved while ensuring the fluidity of the liquid crystal resin composition.

[0043] [(C) Inorganic spherical hollow body] (C) Inorganic spherical hollow bodies are generally referred to as hollow spheres. Examples of materials that can be used as inorganic spherical hollow bodies include alumina, silicon dioxide, and glass. Among these, glass is preferred from the viewpoint of heat resistance and strength. That is, glass spheres are preferred as inorganic spherical hollow bodies. (C) The components can be used alone or in combination of two or more.

[0044] From the perspective of suppressing the increase of melt viscosity, the deterioration of fluidity, and the formability, the aspect ratio of (C) inorganic spherical hollow bodies is preferably 1.15 or higher, more preferably 1.20 or higher and 2.00 or lower, even more preferably 1.22 or higher and 1.50 or lower, and even more preferably 1.25 or higher and less than 1.30. In this specification, the aspect ratio is adopted as follows: using dynamic image analysis / particle state analyzer, the length of the longest part in the particle projection plane, i.e., the maximum length L, and the length of the longest part in the direction perpendicular to the maximum length L in the particle projection plane, i.e., the maximum vertical length S, are measured for 3000 particles. This measurement is repeated several times, and the average value of L / S is calculated for each particle.

[0045] From the viewpoint of formability, the median diameter of component (C) is preferably 5 μm or more, more preferably 10 μm or more. From the viewpoint of damage suppression and formability, the median diameter of component (C) is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. Furthermore, in this specification, the median diameter is the central value of a volume reference measured using a laser refraction / scattering particle size distribution method.

[0046] The content of component (C) relative to the total liquid crystal resin composition is 7.5 to 29% by mass, preferably 9 to 28.5% by mass, and more preferably 15 to 28% by mass. If the content of component (C) is 7.5% by mass or more, a liquid crystal resin composition with excellent dielectric properties can be easily obtained. If the content of component (C) is 29% by mass or less, a liquid crystal resin composition with good flowability can be easily obtained, and the mechanical strength and dielectric properties of the molded article formed by the liquid crystal resin composition can be easily improved.

[0047] The total content of (B) fibrous inorganic filler and (C) inorganic spherical hollow body is 15-43% by mass relative to the total liquid crystal resin composition, preferably 17-41% by mass, and more preferably 22.5-37.5% by mass. If the total content is within the above range, a liquid crystal resin composition with excellent dielectric properties can be easily obtained.

[0048] [(D) Inorganic fillers other than (B) fibrous inorganic fillers and (C) inorganic spherical hollow bodies] The liquid crystal resin composition of the present invention may optionally contain inorganic fillers other than (B) fibrous inorganic fillers and (C) inorganic spherical hollow bodies (D). If the liquid crystal resin composition contains component (D), the molded article of the liquid crystal resin composition readily exhibits improved mechanical strength, such as flexural modulus. Component (D) may be used alone or in combination of two or more. Examples of component (D) include, for instance, plate-shaped fillers and granular fillers.

[0049] (plate-shaped filler) When the liquid crystal resin composition of the present invention contains a plate-shaped filler, the molded body made of the liquid crystal resin composition readily improves mechanical strength such as flexural modulus and easily suppresses warping. The plate-shaped filler can be used alone or in combination of two or more types.

[0050] The median diameter of the plate-like filler is preferably 15-50 μm. If the median diameter is 15 μm or more, it is easier to ensure the necessary mechanical strength, and the warpage suppression effect of the molded article is easily improved. If the median diameter is 50 μm or less, it is easier to improve the fluidity of the composition during melting. Preferably, the median diameter is 20-30 μm.

[0051] As a plate-shaped filler, there are no particular limitations; examples include mica, talc, glass flake, graphite, and various metal foils (such as aluminum foil, iron foil, and copper foil).

[0052] (granular filler) When the liquid crystal resin composition of the present invention contains a granular filler, the molded body made of the liquid crystal resin composition readily improves mechanical strength such as flexural modulus and readily suppresses surface whitening. One type of granular filler may be used alone or in combination of two or more types.

[0053] The median diameter of the granular filler is preferably 0.3 to 5.0 μm. When the median diameter is 0.3 μm or more, it is easier to maintain the impact resistance of the molded article. When the median diameter is 5.0 μm or less, the surface whitening inhibition effect of the molded article is more likely to be higher. The median diameter is more preferably 0.5 to 5.0 μm, and even more preferably 0.5 to 4.0 μm.

[0054] Examples of granular fillers include metal oxides such as silicon dioxide, quartz powder, glass beads, glass powder, potassium aluminum silicate, diatomaceous earth, iron oxide, titanium oxide, zinc oxide, and aluminum oxide; metal carbonates such as calcium carbonate and magnesium carbonate; metal sulfates such as calcium sulfate and barium sulfate; phosphates such as calcium pyrophosphate and anhydrous dicalcium phosphate; silicon carbide; silicon nitride; and boron nitride. In this invention, from the viewpoint of suppressing surface whitening of the molded article and reducing dust generation of the molded article, it is preferable to use one or more selected from the group consisting of silicon dioxide and barium sulfate as granular fillers, and more preferably silicon dioxide as a granular filler.

[0055] The content of component (D) relative to the total liquid crystal resin composition is preferably 0.1 to 5% by mass, more preferably 0.2 to 2% by mass, and even more preferably 0.5 to 1% by mass. When the content of component (D) is within the above range, the fluidity of the liquid crystal resin composition can be sufficiently ensured, and the mechanical strength of the molded article made of the liquid crystal resin composition can be easily improved.

[0056] [Other ingredients] Without impairing the effects of the present invention, other polymers, other fillers, and known substances generally added to synthetic resins may also be appropriately added to the liquid crystal resin composition of the present invention, depending on the desired performance, such as stabilizers, antistatic agents, flame retardants, colorants, lubricants, release agents, crystallization promoters, crystallization nucleating agents, etc., such as antioxidants and ultraviolet absorbers.

[0057] Other polymers refer to polymers other than (A) fully aromatic polyesters, such as copolymers containing epoxy groups. Other fillers refer to fillers other than (B) fibrous inorganic fillers, (C) inorganic spherical hollow bodies and (D) inorganic fillers, such as organic fillers and carbon black.

[0058] [Preparation of Liquid Crystal Resin Compositions] The preparation of the liquid crystal resin composition of the present invention is not particularly limited. For example, the liquid crystal resin composition can be prepared by melt-blending it with component (A), component (B), component (C), optional component (D), and optional other components using a one-shaft or two-shaft extruder.

[0059] [Liquid Crystal Resin Composition] From the viewpoints of melt flowability and processability, the melt viscosity of the liquid crystal resin composition of the present invention obtained as described above is preferably 80 Pa·sec or less, more preferably 75 Pa·sec or less, and even more preferably 73 Pa·sec or less. In this specification, the melt viscosity is a value obtained based on the determination method of ISO 11443 under conditions of a cylinder temperature 10 to 30°C higher than the melting point of the liquid crystal resin and a shear rate of 1000 sec⁻¹.

[0060] The relative permittivity of the liquid crystal resin composition of the present invention at a measurement frequency of 5 GHz is preferably 3.4 or less, more preferably 3.2 or less, and even more preferably 3.0 or less. The dielectric loss tangent of the liquid crystal resin composition of the present invention at a measurement frequency of 5 GHz is preferably 0.0045 or less, more preferably 0.0042 or less, and even more preferably 0.0040 or less.

[0061] <Planar connector> By molding the liquid crystal resin composition of the present invention, a planar connector of the present invention can be obtained. The shape of the planar connector is not particularly limited. The planar connector has an outer frame portion and a grid structure formed inside the outer frame portion, wherein the pitch interval of the grid portions in the grid structure can be 1.5 mm or less. The planar connector may have an opening inside the aforementioned grid structure. The thickness ratio of the aforementioned outer frame portion to the aforementioned grid portion of the planar connector can be 1.0 or less. Furthermore, the planar connector can also be a very thin-walled planar connector, wherein the width of the resin portion holding the terminals of the planar connector is 0.5 mm or less, and the overall height of the product is 5.0 mm or less.

[0062] As an example of the shape of the planar connector of the present invention, the shape shown in Figure 1 can be cited. The overall size of the planar connector is 43.88mm × 43.88mm × 3mm, and it has an outer frame portion with a thickness of 3mm or less, a grid portion with a thickness of 1.5mm or less, and a central opening portion of 13.88mm × 13.88mm. In addition, the width of the pin insertion hole of the planar connector can be partially narrowed to prevent the pins inserted into the planar connector from falling out.

[0063] The shape of the pin insertion hole in the grid portion of the planar connector of the present invention is not particularly limited, and can be square, circular, etc.

[0064] There is no particular limitation on the molding method for obtaining the planar connector of the present invention, but in order to prevent deformation of the obtained planar connector and obtain a planar connector with good flatness, it is preferable to select molding conditions that do not leave residual internal stress. In order to reduce the filling pressure and reduce the residual internal stress of the obtained planar connector, the barrel temperature of the molding machine is preferably a temperature above the melting point of the liquid crystal polymer.

[0065] Additionally, the optimal temperature for the metal mold is 70-100°C. If the metal mold temperature is too low, the composite resin composition filling the mold may experience poor flow, which is undesirable. If the metal mold temperature is too high, problems such as burrs may occur, which is also undesirable. Regarding injection speed, a speed of 150 mm / s or higher is preferred. If the injection speed is too low, unfilled parts may be obtained, and even if fully filled parts are obtained, they may result in parts with high filling pressure and high residual internal stress, leading to connectors with poor flatness.

[0066] The planar connector of the present invention has excellent crack resistance, mechanical strength and dielectric properties. [Example]

[0067] The following examples illustrate the present invention in more detail, but the present invention is not limited to these examples. <Fully Aromatic Polyester>

[0068] ·All-aromatic polyester 1 After loading the following raw materials into the polymerization container, the temperature of the reaction system was raised to 140°C and reacted at 140°C for 1 hour. Then, the temperature was raised to 360°C over 5.5 hours, followed by a reduction in pressure to 5 Torr (667 Pa) over 30 minutes, during which acetic acid, excess acetic anhydride, and other low-boiling components were distilled off while melt polymerization continued. Once the stirring torque reached the specified value, nitrogen gas was introduced, and the pressure was increased from reduced pressure to pressurized pressure. The polymer was discharged from the bottom of the polymerization container, granulating the strands. The resulting granules were heat-treated at 300°C for 3 hours under a nitrogen flow to obtain granules of the fully aromatic polyester 1. The melting point of the granules was 348°C, and the melt viscosity was 9 Pa·s. Furthermore, the melting point of the fully aromatic polyester 1 was determined according to the melting point determination method described later, and the melt viscosity of the fully aromatic polyester 1 was determined in the same manner as the melt viscosity determination method described later. 6-Hydroxy-2-naphthoic acid (HNA): 1218g (48 mol%) 4-Hydroxybenzoic acid (HBA): 37g (2 mol%) 1,4-Einylphenyldicarboxylic acid: 560g (TA): (25 mol%) 4,4'-Dihydroxybiphenyl (BP): 628g (25 mol%) Metal catalyst (potassium acetate catalyst): 165mg Acetic anhydride (acetic anhydride): 1432g

[0069] [Methods for determining melting point] In the DSC manufactured by TA Instruments, after measuring the endothermic peak temperature (Tm1) observed when heating a fully aromatic polyester from room temperature at a rate of 20°C / min, the temperature is held at (Tm1+40)°C for 2 minutes, then temporarily cooled to room temperature at a rate of 20°C / min, and the temperature of the endothermic peak observed when heating again at a rate of 20°C / min is measured again, which is taken as the melting point of the polymer.

[0070] Materials other than fully aromatic polyesters • Glass fiber: ECS03T-786H (manufactured by Nippon Electric Glass Co., Ltd., chopped strands, fiber diameter 10μm, length 3mm, true specific gravity 2.6) • Ground glass fiber: PF70E001 (manufactured by Nittobo Co., Ltd., fiber diameter 10 μm, average fiber length 70 μm (manufacturer's nominal value)) • Glass sphere: Y12000 (SEISHIN ENTERPRISE, Inc., aspect ratio (average) 1.264, median diameter 35μm, true specific gravity 0.6) • Talc: ROWN TALC PP (manufactured by Matsumura Sangyo Co., Ltd., talc, median diameter 14.6μm)

[0071] <Preparation of Liquid Crystal Resin Compositions> The above components were melt-blended at a feed tube temperature of 370°C using a biaxial extruder (TEX30α type manufactured by Nippon Steel Corporation) in the ratios shown in Table 1 to obtain liquid crystal resin composition particles.

[0072] Melt viscosity Using a Capilograph 1B model manufactured by Toyo Seiki Co., Ltd., the melt viscosity of the liquid crystal resin composition was determined according to ISO 11443 at a temperature 10-30°C above the melting point of the liquid crystal resin, through an orifice with an inner diameter of 1 mm and a length of 20 mm, and at a shear rate of 1000 / s. The specific measurement temperature was 370°C. The results are shown in Table 1.

[0073] <average fiber length by weight> The weight-average fiber length of the fibrous inorganic filler in the liquid crystal resin composition was determined by the following method. Five g of the liquid crystal resin composition particles were ashed at 600°C for 2 hours. The ashed residue was thoroughly dispersed in a 5% (w / w) polyethylene glycol aqueous solution and transferred to a petri dish using a dropper. The fibrous inorganic filler was observed using a stereomicroscope. The weight-average fiber length of the fibrous inorganic filler was determined as follows: Ten stereomicroscopic images of the fibrous inorganic filler were imported from a CCD camera to a PC. The average fiber length of 100 fibrous inorganic fillers in each stereomicroscopic image was measured using an image processing method of an image measuring machine (LUZEXFS manufactured by NIRECO Co., Ltd.), for a total of 1000 fibrous inorganic fillers. The results are shown in Table 1.

[0074] <Load-load flexural temperature> Under the following molding conditions, the liquid crystal resin composition was injection molded to obtain ISO test piece A. The test piece was cut into 80mm × 10mm × 4mm pieces to prepare test specimens. Using the test specimens, the load flexural temperature was determined according to ISO 75-1 and 2. The load flexural temperature was used as an indicator of the heat resistance of the molded article. The results are shown in Table 1. [Forming conditions] Forming machine: Sumitomo Heavy Industries, Ltd., SE100DU Material tube temperature: 370℃ Metal mold temperature: 90℃ Ejection velocity: 33mm / sec

[0075] <Bending Test> Under the following molding conditions, the liquid crystal resin composition was injection molded to obtain ISO test piece A. The test piece was then cut into 80mm × 10mm × 4mm pieces to prepare bending test pieces. Using these test pieces, the bending strength, flexural modulus, and bending strain were determined according to ISO 178. The results are shown in Table 1. [Forming conditions] Forming machine: Sumitomo Heavy Industries, Ltd. SE100DU Material tube temperature: 370℃ Metal mold temperature: 90℃ Ejection velocity: 33mm / sec

[0076] <Dielectric Properties> Using a molding machine (Sumitomo Heavy Industries, Ltd. "SE-100DU"), the particles of the Examples and Comparative Examples were molded under the following molding conditions to produce 80mm × 80mm × 1mm flat test pieces. As shown in Figure 3, 80mm × 1mm × 1mm test pieces were cut from one side of the flow perpendicular direction along the back gate side of the flat test piece to 10mm from the inside, with the flow perpendicular direction as the length direction. These were used as test pieces for evaluating the dielectric properties in the flow perpendicular direction. Additionally, as shown in Figure 4, 80mm × 1mm × 1mm test pieces were cut from one side of the flow direction along the flat test piece to 10mm from the inside, with the flow direction as the length direction. These were used as test pieces for evaluating the dielectric properties in the flow direction. For these test pieces, the relative permittivity and dielectric loss tangent were measured at 5GHz using a cavity resonator perturbation method complex dielectric constant evaluation device with the following structure manufactured by Kanto Electron Application Development Co., Ltd. For the relative permittivity and dielectric loss tangent, the average values ​​of the values ​​in the flow right-angle direction and the flow direction were calculated and used as the relative permittivity and dielectric loss tangent of the above-mentioned flat plate test piece. The results are shown in Table 1. Scalar network analyzer: Agilent Technologies 8757D Frequency synthesizer: Agilent Technologies 83650L Swept CW Generator Fixed attenuator: Agilent Technologies 85025D Detector Cavity Resonator: Kanto Electronics Application Development CP431 Measurement Program: Kanto Electronics Application Development CPMA-S2 / V2 [Forming conditions] Material tube temperature: 370℃ Metal mold temperature: 80℃ Ejection velocity: 33mm / sec Pressure holding: 60 MPa

[0077] Crack resistance The liquid crystal resin composition was injection molded into a planar connector (1248 pins) as shown in Figure 1, with overall dimensions of 43.88mm × 43.88mm × 3mm. It has a central opening of 13.88mm × 13.88mm, and a grid pitch of 1.0mm. A special gate (overflow) as shown in Figure 2 was used. The resulting planar connector was subjected to IR reflow under the following conditions, and the grid was observed using an optical microscope to measure the number of cracks. A lower number of cracks indicates higher crack resistance. Specifically, the number of cracks generated in a single planar connector was counted, and crack resistance was evaluated according to the following criteria. ○ (Good): The number of cracks is less than 8. × (Defective): The number of cracks is 8 or more. [IR reflux conditions] Testing equipment: RF-300 large benchtop reflow soldering unit (using far-infrared heater) manufactured by the Pulse Technology Research Institute of Japan. Sample conveying speed: 140mm / sec Reflow oven throughput time: 5 min Temperature conditions: Preheating zone: 150℃ Reflux zone: 240℃ Peak temperature: 260℃ [Forming conditions] Molding machine: Sumitomo Heavy Industries SE100DU Feed tube temperature (indicated by the temperature on the nozzle side): 370℃-370℃-370℃-370℃-380℃ Metal mold temperature: 80℃ Ejection velocity: 2m / min Pressure holding: 50MPa Holding time: 2 seconds Cooldown time: 10 seconds Screw speed: 120 rpm Screw back pressure: 1.2 MPa

[0078] [Table 1] Example Example Example Example Comparative example Comparative example Comparative example Comparative example Comparative example Comparative example Comparative example 1 2 3 4 1 2 3 4 5 6 7 Fully aromatic polyester Monomer composition HNA Moer% 48 48 48 48 48 48 48 48 48 48 48 HBA Moer% 2 2 2 2 2 2 2 2 2 2 2 TA Moer% 25 25 25 25 25 25 25 25 25 25 25 BP Moer% 25 25 25 25 25 25 25 25 25 25 25 total Moer% 100 100 100 100 100 100 100 100 100 100 100 resin composition Fully aromatic polyester quality% 82.5 72.5 65 60 70 60 92.5 75 72.5 55 87.5 filler Fiberglass quality% 7.5 7.5 7.5 12.5 15 10 7.5 15 7.5 Grinding glass fibers quality% 7.5 glass ball quality% 10 20 27.5 27.5 15 30 25 20 5 talc quality% 30 total quality% 17.5 27.5 35 40 30 40 7.5 25 27.5 45 12.5 total quality% 100 100 100 100 100 100 100 100 100 100 100 melt viscosity Pa·s 19 30 40 43 twenty three 50 15 33 27 32 16 fibrous inorganic fillers Average fiber length by weight μm 365 330 300 290 350 300 400 - 100 550 380 Load flexural temperature °C 290 285 280 285 290 285 285 275 280 300 290 Bending strength MPa 130 105 95 100 115 90 150 100 95 185 135 Flexural modulus MPa 7100 6900 6700 7600 7600 6600 7400 5800 6100 14100 7200 Bending strain % 2.5 2.1 1.8 1.7 2.3 1.7 3 2.5 2 1.73 2.7 Dielectric properties Relative permittivity - 3.4 3.0 2.7 2.8 3.5 2.7 3.7 2.7 3.0 4.0 3.5 Dielectric loss tangent - 0.0030 0.0028 0.0040 0.0040 0.0040 0.0050 0.0020 0.0030 0.0028 0.0040 0.0030 Crack resistance - ○ ○ ○ ○ ○ ○ ○ × × ○ ○

[0079] As shown in Table 1, the liquid crystal resin composition of the embodiments enables the manufacture of planar connectors with excellent crack resistance, mechanical strength and dielectric properties, and good flowability.

[0080] none

Claims

1. A liquid crystal resin composition comprising: (A) a fully aromatic polyester; (B) a fibrous inorganic filler; and (C) a planar connector containing inorganic spherical hollow bodies, wherein, Relative to the entire constituent unit, the aforementioned (A) fully aromatic polyester contains the following constituent units (I) to (IV): the content of constituent unit (I) is 40 to 75 mol; the content of constituent unit (II) is 0.5 to 7.5 mol; the content of constituent unit (III) is 8.5 to 30 mol; the content of constituent unit (IV) is 8.5 to 30 mol; the weight-average fiber length of the aforementioned (B) fibrous inorganic filler is 200 to 500 μm; relative to the aforementioned liquid crystal resin composition as a whole, the content of the aforementioned (A) fully aromatic polyester is 57 to 85% by mass; the content of the aforementioned (B) fibrous inorganic filler is 5 to 14% by mass; the content of the aforementioned (C) inorganic spherical hollow body is 7.5 to 29% by mass; the total content of the aforementioned (B) fibrous inorganic filler and the aforementioned (C) inorganic spherical hollow body is 15 to 43% by mass. [Chem. 1] (In the formula, Ar1 and Ar2 each represent exoaryl groups independently).

2. The liquid crystal resin composition as described in claim 1, wherein the aforementioned (B) fibrous inorganic filler is one or more selected from the group consisting of glass fibers and ground glass fibers.

3. The liquid crystal resin composition as described in claim 1 or 2, wherein the aforementioned inorganic spherical hollow body (C) is a glass sphere.

4. The liquid crystal resin composition as described in claim 1 or 2 has a relative permittivity of 3.4 or less at a measurement frequency of 5 GHz.

5. A planar connector comprising a liquid crystal resin composition as described in any one of claims 1 to 4, having an outer frame portion and a grid structure formed on the inner side of the outer frame portion, wherein the pitch interval of the grid portion of the aforementioned grid structure is 1.5 mm or less.

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