JP2015108036A - All aromatic liquid crystal polyester resin composition and camera module component containing injection molded article thereof as constitutional member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an all aromatic liquid crystal polyester resin composition capable of molding a camera module component having less particle number generated during impact or falling down of a portable terminals such as smart phone having a camera.SOLUTION: There is provided an all aromatic liquid crystal polyester resin composition obtained by melting and mixing all aromatic liquid crystal polyester of 50 to 80 mass%, whisker of 10 to 30 mass%, carbon black of 0.5 to 5 mass, talc of 0 to 20 pts.mass and settleability barium sulfate of 3 to 20 pts.mass (all together 100 mass%) and having load deflection temperature of 220°C or more, shear rate of 100 sec-1 and melting viscosity at the melting point +10°C of 20 to 100 Pa s.

Description

  Built-in small digital cameras such as smartphones and tablet terminals have been positioned as one of the main functional units from the additional functional units as the performance of the number of pixels, image quality, etc. has improved.

  Along with this, a problem of preventing particles that are detached from the surface of the camera module component from adhering to the lens has become apparent, and a countermeasure for the problem has been studied. The present invention relates to a liquid crystal polyester resin composition suitably used for such a camera module component, and further relates to a camera module component including a molded body obtained by injection molding the liquid crystal polyester resin composition as a constituent member.

  Many of these studies have been focused on particles that are detached from the surface of the member due to sliding between the camera module component and the lens, which occur when the autofocus function is performed (Patent Documents 1 to 4).

  However, in recent years, with the change in lifestyle and the weight reduction of smartphones and mobile terminal devices, the frequency of carrying them increases, and as the design and downsizing and thinning of devices and members proceed, the sliding In addition to particles that are sometimes generated, suppression of particles that are generated when the device is impacted or dropped (hereinafter, sometimes referred to as “particle detachment resistance” regarding suppression of particles that occur in the latter case) is a new issue. It has become obvious.

JP 2009-242453 A JP 2009-242454 A JP 2009-242455 A JP 2009-242456 A

  In view of the above circumstances, the inventors obtain a wholly aromatic liquid crystal polyester resin composition capable of molding a camera module component that generates a small number of particles when impacted or dropped by a mobile terminal device such as a smartphone equipped with a camera. This is a problem.

  Accordingly, an object of the present invention is to provide a wholly aromatic liquid crystal polyester resin composition capable of obtaining an injection-molded product excellent in particle detachment resistance required for recent camera module parts.

  As a result of diligent investigations to achieve the above object, the present inventors have conducted injection molding of a wholly aromatic liquid crystal polyester resin composition containing a specific liquid crystal polyester resin, whiskers, and carbon black. It has been found that an injection-molded product having “detachment resistance” can be obtained, and the present invention has been completed.

  That is, the first of the present invention is a wholly aromatic liquid crystal polyester 50 to 80% by mass, whisker 10 to 30% by mass, carbon black 0.5 to 5% by mass, talc 0 to 20 parts by mass, precipitated barium sulfate 3 to 3%. 20 parts by mass (totally 100% by mass) obtained by melt-kneading, the deflection temperature under load is 220 ° C. or higher, the shear rate is 100 sec-1, the melting viscosity is 20 to 100 Pa at melting point + 10 ° C. -It is related with the wholly aromatic liquid-crystal polyester resin composition characterized by being S.

  The second aspect of the present invention is the wholly aromatic liquid crystal polyester according to claim 1, wherein the whisker is at least one of calcium silicate and calcium carbonate having a true specific gravity of 3.0 or less. The present invention relates to a resin composition.

  A third aspect of the present invention relates to a camera module component comprising an injection molded product of the wholly aromatic liquid crystal polyester resin composition described in the first or second aspect of the present invention as a constituent member.

  The wholly aromatic liquid crystalline polyester resin composition according to the present invention has good molded product rigidity, heat resistance, mechanical strength, thin-wall processability of the resin composition, mold shape transferability, surface mount of molded product (SMT). It is possible to provide a camera module member that has excellent resistance and “particle detachment resistance” and has extremely excellent characteristics by injection molding.

It is the top view and side view of a test piece for weld strength measurement. It is the top view and side view of a test piece for particle detachment resistance measurement.

  The wholly aromatic liquid crystal polyester resin used in the present invention exhibits melt anisotropy. In the wholly aromatic liquid crystal polyester resin composition according to the present invention, in order to have excellent heat resistance and rigidity, the molded product has an anisotropy based on the rigidity of the molecular structure and is used during injection molding (melting). It is necessary to provide a strong liquid crystal alignment property during molding. For this reason, among liquid crystal polyesters, wholly aromatic liquid crystal polyesters obtained by polycondensation reaction of only aromatic compounds mainly have so-called “mesogens” (rigid sites that exhibit liquid crystallinity), melting points and molding processing. It has liquid crystallinity excellent in the balance of temperature and rigidity of molecular chain, which is preferable.

  The structural unit of the liquid crystal polyester resin constituting the liquid crystal polyester resin composition of the present invention includes, for example, a combination of an aromatic dicarboxylic acid, an aromatic diol and an aromatic hydroxycarboxylic acid, or a heterogeneous aromatic hydroxycarboxylic acid. Specific structural units such as those comprising a combination of an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid and an aromatic diol, and a polyester such as polyethylene terephthalate reacted with an aromatic hydroxycarboxylic acid. For example, the following may be mentioned.

Structural units derived from aromatic hydroxycarboxylic acids:

Structural units derived from aromatic dicarboxylic acids:

Repeating structural units derived from aromatic diols:

  From the viewpoint of the balance of heat resistance, mechanical properties, and moldability, a preferable liquid crystal polyester resin has a structural unit (A1) of 30 mol% or more, and more preferably (A1) and (B1) together. It has more than mol%.

  Particularly preferred liquid crystal polyesters are p-hydroxybenzoic acid (I), terephthalic acid (II), 4,4′-dihydroxybiphenyl (III) (including these derivatives) in an amount of 80 to 100 mol% (provided that (I ) And (II) is 60 mol% or more), and (I), (II), or any other aromatic compound capable of decondensation reaction with (III) is further polycondensed in an amount of 0 to 20 mol%. 90 of a wholly aromatic liquid crystal polyester having a melting point of 320 ° C. or higher, or p-hydroxybenzoic acid (I), terephthalic acid (II), 4,4′-dihydroxybiphenyl (III) (including these derivatives). -99 mol% (provided that the total of (I) and (II) is 60 mol% or more), and other aromatic compounds capable of decondensation reaction with (I), (II), (III) 1-10 mol% (they are 100 mol% Is a wholly aromatic liquid crystalline polyester having a melting point of 320 ° C. or higher.

As a combination of the above structural units,
(A1)
(A1), (B1), (C1)
(A1), (B1), (B2), (C1)
(A1), (B1), (B2), (C2)
(A1), (B1), (B3), (C1)
(A1), (B1), (B3), (C2)
(A1), (B1), (B2), (C1), (C2)
(A1), (A2), (B1), (C1)
As a particularly preferable monomer composition ratio, p-hydroxybenzoic acid, terephthalic acid, 4,4′-dihydroxybiphenyl (including these derivatives) is 80 to 100 mol%, and other aromatic diols, A wholly aromatic liquid crystal polyester resin obtained by polycondensation of 0 to 20 mol% of aromatic compounds selected from the group consisting of aromatic hydroxydicarboxylic acids and aromatic dicarboxylic acids (they are combined to give 100 mol%). It is. When p-hydroxybenzoic acid, terephthalic acid, and 4,4′-dihydroxybiphenyl are 80 mol% or less, the heat resistance tends to decrease, which is not preferable. In the resin composition in the present invention, the composition of the liquid crystal polyester resin is in the range of 50 to 80% by mass. If it deviates from this range, it becomes difficult to obtain sufficient injection molding characteristics (melt flowability, short cycle time, etc.).

  As a method for producing the liquid crystal polyester resin used in the present invention, a known method can be adopted, and a production method by only melt polymerization or a production method by two-stage polymerization of melt polymerization and solid phase polymerization can be used. As a specific example, after a monomer selected from an aromatic dihydroxy compound, an aromatic hydroxycarboxylic acid compound, and an aromatic dicarboxylic acid compound is charged into a reactor, acetic anhydride is added to acetylate the hydroxyl group of the monomer, Produced by deacetic acid polycondensation reaction. For example, p-hydroxybenzoic acid, terephthalic acid, isophthalic acid, and 4,4′-dihydroxybiphenyl are charged into a reactor under a nitrogen atmosphere, acetic anhydride is added, and acetoxylation is performed under acetic anhydride reflux, followed by ascending. The method of manufacturing a polyester resin is mentioned by performing deacetic acid melt polycondensation, heating and distilling acetic acid in the temperature range of 150-350 degreeC. The polymerization time can be selected in the range of 1 hour to several tens of hours. In the production of the liquid crystalline polyester resin used in the present invention, the moisture in the monomer may or may not be dehydrated before production.

  When solid phase polymerization is further performed on the polymer obtained by melt polymerization, the polymer obtained by melt polymerization is solidified and then pulverized into powder or flakes, and then a known solid phase polymerization method such as nitrogen A method such as heat treatment in a temperature range of 200 to 350 ° C. in an inert gas atmosphere such as 1 to 30 hours is preferably selected. The solid phase polymerization may be performed with stirring, or may be performed in a standing state without stirring.

  In the polymerization reaction, a catalyst may or may not be used. As the catalyst to be used, those conventionally known as polyester polycondensation catalysts can be used, such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide. Examples thereof include metal salt catalysts and organic compound catalysts such as N-methylimidazole.

  The polymerization reaction apparatus in melt polymerization is not particularly limited, but a reaction apparatus used for reaction of a general high viscosity fluid is preferably used. Examples of these reaction apparatuses include, for example, a stirring tank type polymerization reaction apparatus having a stirring apparatus having stirring blades of various shapes, such as a vertical type, a multistage type, a spiral band type, a helical shaft type, etc. And a kneader, a roll mill, a Banbury mixer, and the like, which are generally used for resin kneading.

  The shape of the liquid crystalline polyester resin used in the present invention may be any of powder, granule, and pellet, but is preferably powder or granule from the viewpoint of dispersibility when mixed with a filler.

<About whiskers (acicular single crystals)>
Liquid crystal polyester resin compositions may contain a wide variety of fibrous fillers, and are known to exhibit excellent heat resistance, rigidity, and the like due to their shape factors. In the present invention, it is necessary to include so-called “whiskers” which are needle-like single crystals as the fibrous filler, and to further contain a filler different from this in a specific blending ratio.

“Particle detachment resistance” of the liquid crystal polyester resin composition for camera modules is remarkably improved by adding whiskers as the fibrous filler in the resin composition having the specific composition.
The present inventors have not yet clarified the reason for this, but can make assumptions in comparison with glass fibers as typical examples of fibrous fillers.

  It has been elucidated that particles in a drop impact of a liquid crystal polyester resin composition containing various fillers are mainly fibrils derived from fragments of various fibrous fillers and destruction of the liquid crystal polyester matrix.

It is considered that the generation of particles is largely caused by the fracture mode of interfacial peeling between the fibrous filler having a large aspect ratio and size (length) and the liquid crystalline polyester among the fillers.
In the case of a glass fiber produced by melt spinning and melt blowing and having a rough surface shape and its fracture surface shape, and a needle-like single crystal produced by crystal growth and having a relatively smooth surface shape and its fracture surface shape, a matrix It is expected that the interface structure with the liquid crystal polyester is different microscopically, and the fracture mode of the interface is different.
For example, the needle-like single crystal interface having a relatively smooth surface and the liquid crystal polyester resin are easily peeled to form a large number of minute voids, and the impact energy is absorbed by the formation of these voids. It is considered that the destruction of the matrix part that leads to the generation of fibrils (one of the main components of “particles”) is suppressed.

  There are no restrictions on the whiskers that can be used in the present invention. Preferably, among whiskers, an average diameter of 5 μm or less having toughness is suitable. Specifically, (i) potassium titanate (chemical formula; K 2 O · nTiO 2 (n is 6 or 8, true specific gravity 3.4 to 3.6, average fiber diameter 0.3 to 0.6 μm. For example, from the market, Product name “Tismo” (available from Otsuka Chemical Co., Ltd.), (ii) calcium silicate (chemical formula; CaSiO 3, true specific gravity 2.5 to 2.6, fiber diameter 1 to 5 μm. For example, from the market (Iii) What is available as “Wollastonite”, (iii) Calcium carbonate (chemical formula; CaCO 3, true specific gravity 2.8, average fiber diameter 0.5-1 μm) Iv) Zinc oxide, (chemical formula: ZnO, true specific gravity 5.78, average fiber diameter 0.2-3 μm. For example, trade name “Panatetra” (manufactured by Panasonic Corporation) from the market Among these, from the viewpoint of ease of handling in the kneading process and ease of dispersion in the liquid crystal polyester constituting the matrix, the fiber diameter is relatively large. (Ii) and (iii) are preferable because they have a small specific gravity difference and easy to disperse, and these may be used alone or in admixture of two or more. In the resin composition of the present invention, the whisker content is preferably in the range of 10 to 30% by mass, and if it is less than 10% by mass, the effect of addition is not sufficient. It may be difficult to obtain good fluidity.

<Precipitated barium sulfate>
The liquid crystal polyester resin composition in the present invention contains precipitated barium sulfate. Barium sulfate is an almost spherical filler, and has a low probability of adopting an interfacial debonding failure mode that leads to particle generation. Also, due to its specific high specific gravity (about 4.5), the impact energy of liquid crystal polyester composition It is considered that the absorption efficiency is improved and the effect of suppressing particle generation is given. In addition, the fact that it is amorphous, very thin, soft, and difficult to break is considered to have led to the suppression of particle generation. In the resin composition in the present invention, when precipitating barium sulfate is added, the content is preferably in the range of 3 to 20% by mass. If it is less than 3% by mass, the effect of addition is not sufficient, and if it exceeds 20% by mass, it may be difficult to obtain good fluidity.

<Talc>
In the present invention, the liquid crystal polyester resin composition preferably contains talc. Talc is an oval-shaped filler with a relatively smooth surface, and provides dimensional stability to molded products by reducing anisotropy. It is possible to improve the reliability. In the resin composition in this invention, when adding talc, it is preferable to make the content rate into the range of 5-20 mass%. If it is less than 5% by mass, the effect of addition is not sufficient. If it exceeds 20% by mass, it may be difficult to obtain good fluidity.

<About carbon black>
The carbon black used in the present invention is used for the purpose of ensuring the light shielding property of the camera module parts, and is not particularly limited as long as it is generally available for use in resin coloring.
In the resin composition in the present invention, the carbon black content is preferably in the range of 0.5 to 5% by mass. More preferably, it is 2-4 mass%. If the blending amount of the carbon black is less than 0.5% by mass, the jet blackness of the resulting resin composition is lowered, and sufficient light-shielding properties cannot be secured. The possibility of generation of fine bumpy projections with agglomerated carbon black is increased.

  Further, the composition of the present invention includes an antioxidant and a heat stabilizer (for example, hindered phenol, hydroquinone, phosphites and substituted products thereof), an ultraviolet absorber (in the range not impairing the object of the present invention). For example, resorcinol, salicylate, benzotriazole, benzophenone, etc., lubricant and mold release agent (montanic acid and its salt, its ester, its partial ester, higher fatty acid and its salt such as stearic acid, its ester, higher alcohol such as stearyl alcohol, stearyl Amide and polyethylene wax (polyolefin wax, etc.), plasticizers, antistatic agents, flame retardants and other normal additives, other fillers and other thermoplastic resins other than those mentioned above, and the addition of the specified characteristics Can do. In addition, glass fiber has many particle generation numbers and is not suitable for the objective of this invention (refer comparative example).

The liquid crystal polyester resin composition according to the present invention can be obtained by melting the liquid crystal polyester and kneading it with other components. The equipment and operation method used for the melt kneading are generally those used for melt kneading of the liquid crystal polyester. There is no particular limitation.
Preferably, in a kneader having a pair of screws, liquid crystal polyester, whisker, carbon black, precipitated barium sulfate is added from a popper, and further, talc is added as necessary, and melt-kneaded and pelletized. Is preferred.
These are called twin-screw extruders, and among these, those that are different-direction rotating types that enable uniform dispersion of fillers and suppression of local heat generation by having a switching mechanism are preferable.

<About melt viscosity range>
In the present invention, the liquid crystal polyester resin composition thus obtained has a melt viscosity of 20 to 100 Pa · S, preferably 30 to 80 Pa · S, measured at a shear rate of 100 sec ⁻¹ and a melting point + 10 ° C. There is. If the resin viscosity is out of this range, the surface properties of the injection-molded product are deteriorated, and there is a risk of generation of particles due to this. The melt viscosity is a capillary rheometer (Model 2010) manufactured by Intesco Corporation, a capillary having a diameter of 1.00 mm, a length of 40 mm and an inflow angle of 90 °, a melting point of −40 ° C. to + 4 ° C. at a shear rate of 100 sec ^−1. The apparent viscosity is measured while heating at a constant rate at a heating rate of 1 min / min, and the apparent viscosity at the melting point + 10 ° C. is determined by rounding off to the first decimal place.

<About deflection temperature under load>
In the present invention, it is necessary that the deflection temperature under load of the injection-molded product of the liquid crystal polyester resin composition thus obtained is 220 ° C. or higher. Here, the deflection temperature under load means the deflection temperature under load (DTUL) measured according to ASTM D648. If the deflection temperature under load is less than 220 ° C., there is a possibility that a problem arises in heat resistance during solder reflow in surface mounting, which is not suitable.

  In the resin composition according to the present invention, individual characteristics of these constituent materials and good fluidity are comprehensively exhibited in the injection molding process, and in particular, a thickness in the range of 0.3 to 0.9 mm. In the molding of an injection molded product having a thin structure portion, a camera module component having excellent “particle detachment resistance” is supplied. The injection molding machine used for injection molding is not particularly limited as long as it is a known machine that is generally used for molding liquid crystal polyester.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to a following example.

A production example of liquid crystal polyester (LCP) is shown below.
(Production example Production of thermotropic liquid crystal polyester A)
P-Hydroxybenzoic acid (manufactured by Ueno Pharmaceutical Co., Ltd.) 298 kg (2.16 kgol), 4,4′- in a 1700 L polymerization tank (manufactured by Kobe Steel Co., Ltd.) having a double helical stirring blade made of SUS316. Dihydroxybiphenyl (Honshu Chemical Industry Co., Ltd.) 134 kg (0.72 kgmol), Terephthalic acid (Mitsui Chemicals Co., Ltd.) 90 kg (0.54 kgmol), Isophthalic acid (Ai International Chemical Co., Ltd.) 30 kg ( 0.18 kgmol), 0.04 kg of potassium acetate (manufactured by Kishida Chemical Co., Ltd.) as a catalyst, and 0.10 kg of magnesium acetate (manufactured by Kishida Chemical Co., Ltd.) were charged. After that, 386 kg (3.78 kgol) of acetic anhydride was added, and the rotating speed of the stirring blade was 45 r. 2 hours acetylation reaction was carried out at a Atsushi Nobori to reflux for 1.5 hours 0.99 ° C. by m. After completion of acetylation, acetic acid was distilled off and the temperature was raised at 0.5 ° C./min. When the reactor temperature reached 305 ° C., the polymer was taken out from the outlet at the bottom of the reactor and solidified by cooling with a cooling device. The obtained polymer was pulverized by a pulverizer manufactured by Hosokawa Micron Co., Ltd. into a size passing through a sieve having an opening of 2.0 mm to obtain a prepolymer.
The obtained prepolymer was subjected to solid phase polymerization using a rotary kiln manufactured by Takasago Industry Co., Ltd. The prepolymer was filled in the kiln, nitrogen was passed at a flow rate of 16 Nm 3 / hr, the heater temperature was raised from room temperature to 350 ° C. in 1 hour at a rotation speed of 2 rpm, and the temperature was maintained at 350 ° C. for 10 hours. After confirming that the temperature of the resin powder in the kiln reached 295 ° C., the heating was stopped and the rotary kiln was rotated and cooled for 4 hours to obtain a powdery liquid crystal polyester. The melting point was 360 ° C. and the melt viscosity was 70 Pa · S. The melting point was measured according to ISO11357-3 and ASTM D3418 (hereinafter the same).

(Production example Production of thermotropic liquid crystal polyester B)
A prepolymer was obtained in the same manner as the thermotropic liquid crystal polyester A. The obtained prepolymer was subjected to solid phase polymerization using a rotary kiln manufactured by Takasago Industry Co., Ltd. The prepolymer was filled in the kiln, nitrogen was passed at a flow rate of 16 Nm 3 / hr, the heater temperature was raised from room temperature to 350 ° C. in 1 hour at a rotation speed of 2 rpm, and held at 350 ° C. for 9 hours. After confirming that the temperature of the resin powder in the kiln reached 290 ° C., the heating was stopped and the rotary kiln was rotated and cooled for 4 hours to obtain a powdery liquid crystalline polyester. The melting point was 350 ° C. and the melt viscosity was 20 Pa · S.

(Production example Production of thermotropic liquid crystal polyester C)
A prepolymer was obtained in the same manner as the thermotropic liquid crystal polyester A. The obtained prepolymer was subjected to solid phase polymerization using a rotary kiln manufactured by Takasago Industry Co., Ltd. The prepolymer was filled in the kiln, nitrogen was passed at a flow rate of 16 Nm 3 / hr, the heater temperature was raised from room temperature to 350 ° C. in 1 hour at a rotation speed of 2 rpm, and the temperature was maintained at 350 ° C. for 11 hours. After confirming that the temperature of the resin powder in the kiln reached 300 ° C., the heating was stopped and the rotary kiln was rotated and cooled for 4 hours to obtain a powdery liquid crystalline polyester. The melting point was 370 ° C. and the melt viscosity was 140 Pa · S.

(Production example Production of thermotropic liquid crystal polyester D)
P-Hydroxybenzoic acid (Ueno Pharmaceutical Co., Ltd.) 97.5 kg (1.43 kgol), 4, 4 in a polymerization tank (made by Kobe Steel Co., Ltd.) having an internal volume of 1700 L made of SUS316 and having a double helical stirring blade '-Dihydroxybiphenyl (manufactured by Honshu Chemical Industry Co., Ltd.) 71.7 kg (0.385 kgol), terephthalic acid (manufactured by Mitsui Chemicals) 64.0 kg (0.385 kgol), potassium acetate (Kishida Chemical Co., Ltd.) as a catalyst Manufactured) 0.06 kg, magnesium acetate (manufactured by Kishida Chemical Co., Ltd.) 0.10 kg, the pressure in the polymerization tank-nitrogen injection was performed twice to perform nitrogen substitution, and then acetic anhydride 242.6 kg (2.4 kgol) ) Was added, and the temperature was raised to 150 ° C. over 1.5 hours at a rotating speed of the stirring blade of 45 rpm, followed by acetylation reaction for 2 hours in the reflux state. After completion of acetylation, acetic acid was distilled off and the temperature was raised at 0.5 ° C./min. At 305 ° C., the polymer was taken out from the outlet at the bottom of the reactor and solidified by cooling with a cooling device. The obtained polymer was pulverized by a pulverizer manufactured by Hosokawa Micron Co., Ltd. into a size passing through a sieve having an opening of 2.0 mm to obtain a prepolymer.
The obtained prepolymer was subjected to solid phase polycondensation using a rotary kiln manufactured by Takasago Industry Co., Ltd. The shape of the kiln inner cylinder is generally a regular hexagon, and has a side length of 500 mm and a total length of 3500 mm. 150 kg of the prepolymer was charged in the kiln, nitrogen was circulated for 15 Nm3 hours, the temperature in the 2 rpm rotation heater was raised from room temperature to 400 ° C. over 5 hours, and maintained at 400 ° C. for 12 hours. After confirming that the temperature of the pulverized product reached 340 ° C., the heating was stopped and the rotary kiln was rotated and cooled for 7 hours to obtain a wholly aromatic liquid crystal polyester D. The melting point was 380 ° C. and the melt viscosity was 70 Pa · S.

The characteristics of various fillers used in Examples and Comparative Examples according to the present invention are shown below.
(1) Whisker:
(I) Potassium titanate: Chemical formula; K2O · nTiO2: n is 6 or 8, true specific gravity 3.4 to 3.6, fiber diameter 0.3 to 0.6 μm (trade name “Tismo”, Otsuka Chemical Co., Ltd.) Made)
(Ii) Calcium silicate: Chemical formula; CaSiO 3, true specific gravity 2.5 to 2.6, average fiber diameter 1 to 5 μm (available from the market under the name “Wollastonite”)
(Iii) Calcium carbonate: Chemical formula; CaCO 3, true specific gravity 2.8, average fiber diameter 0.5-1 μm (trade name “Wiscal”, manufactured by Maruo Calcium Co., Ltd.)
(Iv) Zinc oxide: (Chemical formula; ZnO True specific gravity 5.78 Average fiber diameter 0.2-3 μm (trade name “Panatetra”, manufactured by Amtec Co., Ltd.)
(2) Carbon black (CB): “REGAL 660” (primary particle size: 24 nm), manufactured by Cabot Corporation
(3) Precipitated barium sulfate: “BMH-40” manufactured by Sakai Chemical Industry Co., Ltd. (average particle size 1 μm, specific gravity 4.5)
(4) Talc: “MS-KY” manufactured by Nippon Talc Co., Ltd. (number average particle size 23 μm)
(5) Glass fiber.
PF100E-001SC (number average fiber length 100 μm, number average fiber diameter 10 μm) manufactured by Nitto Boseki Co., Ltd.

(Test method)
(1) Measurement of melt viscosity The melt viscosity of the thermotropic liquid crystal polyester resin composition is a capillary rheometer (2010 manufactured by Intesco Corporation), and has a diameter of 1.00 mm, a length of 40 mm, and an inflow angle of 90 °. The apparent viscosity is measured while heating at a constant rate from (melting point −40) ° C. to + 4 ° C./min at a shear rate of 100 sec-1 and rounded to one decimal place. The viscosity was determined and used as the test value. In the test, a resin composition dried in advance in an air oven at 150 ° C. for 4 hours was used.

(2) Weld strength measurement (molding of test pieces)
The pellets of the resin composition thus obtained were tested using an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd., UH-1000) at a cylinder maximum temperature of 370 ° C., an injection speed of 300 mm / sec, and a mold temperature of 80 ° C. Obtained. Resin was injected by a two-point gate. The mold used was a mold having a cavity of 48 mm × 15 mm × 0.3 mm, in which a melt front of resin injected from different gates collided at the center to generate a weld crossing the molded product. FIG. 1 shows a plan view and a side view of the test piece obtained with this mold.
(Evaluation of weld strength)
For each brand, five test pieces were arranged on a resin frame so that both ends were arranged in a frame frame and a central portion having a weld was arranged in a frame window, and both ends on the frame were fixed to the frame with an adhesive tape. After dropping the frame holding the test piece from the height of 1.5 m five times, the presence or absence of cracks in the weld was confirmed with a loupe. Those where no cracks occurred were marked with “◯”, and those where cracks occurred were marked with “x”.

(3) Measurement of deflection temperature under load (DTUL) Using an injection molding machine, pellets of the resin composition obtained were cylinder maximum temperature 370 ° C, injection speed 100mm / sec, mold temperature 80 ° C, 13mm (width) An injection molded product of × 130 mm (length) × 3 mm (thickness) was obtained and used as a test piece for measuring the deflection temperature under load. About each test piece, the deflection temperature under load was measured based on ASTM D648. As a guideline for whether or not the surface mounting can be applied, “◯” indicates that the temperature is 220 ° C. or higher, and “X” indicates that the temperature is less than 220 ° C.

(4) Measurement of particle detachment resistance as a camera module component (molding of test piece)
The pellets of the resin composition thus obtained were tested using an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd., UH-1000) at a cylinder maximum temperature of 370 ° C., an injection speed of 300 mm / sec, and a mold temperature of 80 ° C. Obtained. Resin was injected by a one-point gate, and a mold having a 6 mmφ circular recess at the center of a square shape of 8 mm piece and a 3 mmφ window at the center was used. The minimum thickness is 0.9 mm. The window portion of the molded product corresponds to the lens insertion / fixing portion of the actual camera module part. However, in such a molded product, a dotted line weld is inevitably generated. FIG. 2 shows a plan view and a side view of the test piece obtained with this mold.
(Evaluation of particle detachment resistance)
50 test pieces were placed in a SUS container and closed. The storage container was dropped 50 times from a height of 1.5 m, then the lid was opened, the test piece and the particles dropped from the test piece were separated, and the number of particles was counted with “FPIA-3000” manufactured by Sysmex. .
Evaluation of anti-depletion particles is evaluated in three stages, “◎” indicates that the number of generated particles is in the range of less than 100, “◯” indicates that the number of generated particles is in the range of 100 or more and less than 200, and exceeds 200. It was set as “x”.

(5) Evaluation of anisotropy Evaluation was performed based on a difference in molding shrinkage between the TD direction and the MD direction. Five test pieces for measuring “deflection temperature under load” obtained in (3) above per brand were left at room temperature for 24 hours or longer, then length in the MD (molding) direction and width in the TD (lateral) direction. Was measured in mm to the second decimal place. Each average value of these dimensions was compared with the actual dimensions of the mold (“length” = 130.02 mm, “width” = 13.02 mm), and molding shrinkage rates in the TD direction and the MD direction were obtained.
A case where the difference in molding shrinkage between the TD direction and the MD direction was less than 8 times was designated as “◯”, and a case where the difference was 8 times or more was designated as “Δ”.

  The camera module component comprising an injection molded product of the wholly aromatic liquid crystal polyester resin composition according to the present invention as a constituent member has heat resistance to withstand solder reflow, and can be applied to injection molding of a component having a thin-walled portion. In addition, after being incorporated in the product, because it is excellent in `` particle detachment resistance '' at the time of product drop impact, in mobile phones, laptop computers, digital cameras, digital video cameras, smartphones, cameras with tablet terminals, etc. It can be used for various purposes such as a lens barrel portion, a mount holder portion, and a “CMOS (image sensor) frame”, “shutter and shutter bobbin portion”.

Claims (3)

  Total aromatic liquid crystal polyester 50 to 80% by mass, whisker 10 to 30% by mass, carbon black 0.5 to 5% by mass, talc 0 to 20 parts by mass, precipitated barium sulfate 3 to 20 parts by mass, 100% by mass) obtained by melt-kneading and having a deflection temperature under load of 220 ° C. or higher, a shear rate of 100 sec-1, and a melt viscosity at (melting point + 10) ° C. of 20 to 100 Pa · S. A wholly aromatic liquid crystal polyester resin composition.   2. The wholly aromatic liquid crystal polyester resin composition according to claim 1, wherein the whisker is at least one of calcium silicate and calcium carbonate having a true specific gravity of 3.0 or less.   A camera module component comprising the injection molded product of the wholly aromatic liquid crystal polyester resin composition according to claim 1 or 2 as a constituent member.

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