TW201522578A - Wholly aromatic liquid crystal polyester resin composition and camera module component including injection-molded article of same as constituent member - Google Patents

Abstract

The present invention makes it possible to obtain a wholly aromatic liquid crystal polyester resin composition with which it is possible to mold a camera module component in which the number of particles that occur when a mobile terminal device such as a smartphone equipped with a camera suffers an impact or falls is low. The invention is implemented by means of a wholly aromatic liquid crystal polyester resin composition that can be obtained by melt-kneading 50-80 mass% of a wholly aromatic liquid crystal polyester, 10-30 mass% of whiskers, 0.5-5 mass% of carbon black, 0-20 parts by mass of talc, and 3-20 parts by mass of precipitated barium sulfate (together, the above constitute 100 mass%), and is characterized in that the heat deflection temperature is at least 220 DEG C, and the melt viscosity at a shear rate of 100 sec-1 and a melting point of +10 DEG C is 20-100 Pa.s.

Description

Full aromatic liquid crystal polyester resin composition and camera module part including the same as the component

Embedded small-sized digital cameras such as smart phones and tablet terminals are gradually being positioned as one of the main functional sections from the additional function section due to the accelerated performance improvement of the number of pixels and the image quality.

Along with this, the problem of preventing particles which are detached from the surface of the camera module member from adhering to the lens is highlighted, and the correspondence is reviewed. The present invention relates to a liquid crystal polyester resin composition suitable for use in such a camera module component, and further relates to a camera module member comprising a molded body obtained by injection molding the liquid crystal polyester resin composition as a constituent component.

When most of the reviews are performed by the autofocus function, the camera module member and the lens are slid, and the particles that are separated from the surface of the component are evaluated as the center (Patent Documents 1 to 4).

However, in recent years, with the change of lifestyles, the weight reduction of smart phones and portable terminal devices, the carrying frequency of such devices has increased, and when the design, miniaturization, and thinning of machines and components have progressed, In addition to the particles generated during the sliding, it is also a new problem to suppress the particles generated during the impact of the machine and the particles generated during the fall (hereinafter, the particles generated by suppressing the latter may be referred to as "particle separation resistance"). Highlighted.

Advanced technical literature

Patent literature

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2009-242453

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2009-242454

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2009-242455

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2009-242456

Problem to be solved by the invention

In view of the above circumstances, the inventors and the like have an object of obtaining a composition of a wholly aromatic liquid crystal polyester resin capable of molding a camera module member, and in the case of a portable terminal device such as a smart phone equipped with a camera or When dropped, the number of particles produced by the aforementioned camera module components is very small.

Accordingly, it is an object of the present invention to provide a wholly aromatic liquid crystal polyester resin composition which can obtain an injection molded body excellent in particle release resistance required for camera module parts in recent years.

Technical means of solving problems

In order to achieve the above object, the inventors of the present invention have conducted an intensive review and found that a composition of a wholly aromatic liquid crystal polyester resin comprising a specific liquid crystal polyester resin, whiskers, and carbon black can be injection molded. The injection molded body of the particle detachment resistance is completed to complete the present invention.

That is, the first aspect of the present invention relates to a wholly aromatic liquid crystal polyester resin composition characterized by comprising 50 to 80% by mass of total aromatic liquid crystal polyester, 10 to 30% by mass of whiskers, and carbon black. 0.5 to 5% by mass, 0 to 20% by mass of talc, and 3 to 20% by mass of precipitated barium sulfate (100% by mass or more in total) are obtained by mixing and stirring, and the deflection temperature of the load is 220 ° C or more, and the shearing is performed. The melt viscosity at a cutting speed of 100 sec ^-1 and a melting point of +10 ° C is 20 to 100 Pa‧S.

A second aspect of the present invention relates to a wholly aromatic liquid crystal polyester resin composition according to a first aspect, characterized in that the whisker is at least one of calcium citrate and calcium carbonate having a true specific gravity of 3.0 or less.

A third aspect of the present invention relates to a camera module component characterized by comprising: an injection molded body of a wholly aromatic liquid crystal polyester resin composition of the first aspect or the second aspect of the present invention as a constituent component; to make.

Effect of invention

The wholly aromatic liquid crystal polyester resin composition of the present invention has good rigidity, heat resistance, mechanical strength, thin layer processability of a resin composition, mold shape transferability, and surface adhesion (SMT) resistance of a molded article. Sex, and "particle detachment resistance", it is possible to provide a camera module assembly with extremely good characteristics by injection molding.

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Fig. 1 is a plan view and a side view of a test piece for measuring a weld strength.

Fig. 2 is a plan view and a side view of a test piece for measurement of particle detachment resistance.

Form for implementing the invention

The wholly aromatic liquid crystal polyester resin group used in the present invention exhibits melt anisotropy. In the case of the wholly aromatic liquid crystal polyester resin composition of the present invention, in order to impart good heat resistance and rigidity to the molded body, it is necessary to utilize the anisotropy of the rigidity of the molecular structure at the time of injection molding (melting) When molding, it has a strong liquid crystal alignment. Therefore, in the liquid crystal polyester, in particular, the wholly aromatic liquid crystal polyester obtained by the polycondensation reaction using only the aromatic compound mainly has a so-called "mesogenic" (a rigid portion exhibiting liquid crystallinity), It is suitable for liquid crystallinity having a good balance between melting point, molding processing temperature and molecular chain rigidity.

The structural unit of the liquid crystal polyester resin constituting the liquid crystal polyester resin composition of the present invention may, for example, be composed of an aromatic dicarboxylic acid, an aromatic diol, or a combination of an aromatic hydroxycarboxylic acid; a compound consisting of a combination of heterogeneous aromatic hydroxycarboxylic acids; a compound consisting of an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid, and a combination of aromatic diols; and a polyethylene terephthalate or the like The ester is obtained by reacting an aromatic hydroxycarboxylic acid, etc., and specific structural units are, for example, the following.

Construction unit from aromatic hydroxycarboxylic acid:

[Chemical 1]

(X ₁ : halogen atom or alkyl group)

Construction unit from aromatic dicarboxylic acid:

[Chemical 2]

(X ₂ : halogen atom, alkyl group, or aryl group)

Repeated structural units from aromatic diols:

[Chemical 3]

(X ₂ : halogen atom, alkyl group, or aryl group)

(X ₃ :H, halogen atom, or alkyl group)

From the viewpoint of balance between heat resistance, mechanical properties, and molding processability, a preferred liquid crystal polyester resin has a structural unit (A1) of 30 mol% or more, and more preferably (A1) and (B1)) has a total of 60 m. More than 8% of the ear.

Particularly suitable liquid crystal polyesters are as follows: 80 to 100 moles of p-hydroxybenzoic acid (I), terephthalic acid (II), 4,4'-dihydroxybiphenyl (III) (including derivatives thereof) % (wherein the total of (I) and (II) is 60 mol% or more), and other aromatic compounds which can be decondensed with one of (I), (II) and (III) ~20 mol% of polyaromatic 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 derivatives thereof) 90 to 99 mol% (wherein the total of (I) and (II) is 60 mol% or more), and may be combined with (I), (II), III) A wholly aromatic liquid crystal polyester having a melting point of 320 ° C or more, which is obtained by polycondensation of 1 to 10 mol% of other aromatic compounds subjected to a decondensation reaction (to a total of 100 mol% thereof).

The combination of the above structural units is as follows:

(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)

Particularly suitable monomer composition ratio is 80 to 100 mol% of p-hydroxybenzoic acid, terephthalic acid, 4,4'-dihydroxybiphenyl (including derivatives thereof), and other selected from the group consisting of A group consisting of an aromatic diol, an aromatic hydroxy dicarboxylic acid, and an aromatic dicarboxylic acid, which is a polyaromatic liquid crystal polyester obtained by polycondensation. When the hydroxybenzoic acid, terephthalic acid, and 4,4'-dihydroxybiphenyl are 80 mol% or less, the heat resistance tends to be lowered, which is not preferable. In the resin composition of the present invention, the composition of the liquid crystal polyester resin is in the range of 50 to 80% by mass. When it is out of this range, it is difficult to obtain sufficient injection molding characteristics (melt flowability, short cycle time, etc.).

The method for producing the liquid crystal polyester resin used in the present invention can be carried out by a conventional method, and can be carried out by a production method by melt polymerization or a two-stage polymerization by melt polymerization and solid phase polymerization. Specifically, the reactor is charged with a monomer selected from the group consisting of an aromatic dihydroxy compound, an aromatic hydroxycarboxylic acid compound, and an aromatic dicarboxylic acid compound, and acetic anhydride is added to acetate the hydroxyl group of the monomer. It is produced by a deacetic acid polycondensation reaction. For example, a reactor under a nitrogen atmosphere, in which p-hydroxybenzoic acid, terephthalic acid, isophthalic acid, and 4,4'-dihydroxybiphenyl are added, acetic anhydride is added, and the acetic anhydride is refluxed. A method of producing a polyester resin by subjecting acetic acid to a temperature of from 150 to 350 ° C while distilling off acetic acid, followed by deacetation, melt condensation and condensation. The polymerization time can be selected from the range of 1 hour to several tens of hours. In the production of the liquid crystal polyester resin used in the present invention, the dehydration and drying of the water may or may not be carried out in the monomer before the production.

When the polymer obtained by melt polymerization is further subjected to solid phase polymerization, the polymer obtained by melt polymerization is solidified and then pulverized to form a powder or a sheet, and then a conventional solid phase polymerization method is preferably selected. For example, a method of heat treatment for 1 to 30 hours in a temperature range of 200 to 350 ° C in an inert gas atmosphere such as nitrogen. The solid phase polymerization may be carried out while stirring, or may be carried out without being stirred.

It is possible to use or not use a catalyst in the polymerization reaction. As the catalyst to be used, a catalyst for polycondensation of polyester can be used, and examples thereof include metal salts such as magnesium acetate, tin acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide. Catalyst, organic compound catalyst such as N-methylimidazole, etc.

The polymerization apparatus in the melt polymerization is not particularly limited, and a reaction apparatus for a general high viscosity fluid reaction is preferably used. Examples of such a reaction apparatus include, for example, a stirred tank type polymerization apparatus having an anchor type, a multi-layer type, a spiral belt type, a spiral shaft type, or the like, or a stirring device for stirring the impellers of various shapes, or A kneading machine, a roll mill, a Banbury compact kneader, and the like are generally used in a mixing device for resin mixing and the like.

The shape of the liquid crystal polyester resin used in the present invention may be any of powder, granules, and pellets, but is preferably in the form of powder or granules from the viewpoint of dispersibility when mixed with the filler.

<About whiskers (needle-shaped single crystal)>

The liquid crystal polyester resin composition sometimes contains various types of fibrous fillers, and it is known that it exhibits good heat resistance and rigidity due to its shape. In the present invention, as the fibrous filler, a needle-like single crystal, that is, a so-called "whisker" is contained, and further, a filler different from the filler is contained in a specific blending ratio.

The "particle release resistance" of the liquid crystal polyester resin composition for a camera module is markedly enhanced by containing whiskers as a fibrous filler in the resin composition composed of the above specific composition.

The reason why the inventors of the present invention have not yet reached a clear explanation is conceivable in comparison with a representative glass fiber of a fibrous filler.

The fine particles of the liquid crystal polyester resin composition containing various filler materials at the time of drop impact have been known mainly from the fragments of various fibrous filler materials and the filaments destroyed by the liquid crystal polyester resin matrix.

The generation of the fine particles is mainly caused by the fracture pattern of the interfacial peeling of the fibrous filler and the liquid crystal polyester which are particularly large in the aspect ratio and the dimensional ratio (length) in the filler.

Between the melt-spinning, the surface shape produced by melt-blowning and the glass fiber having a rough cross-sectional shape, and the surface shape and the needle-shaped single crystal which are smoothed by crystal growth, and as a matrix The interface structure of the liquid crystal polyester is microscopically different, and the damage pattern of the predicted interface will be different.

For example, a needle-like single crystal interface having a relatively smooth surface and a liquid crystal polyester resin are easily peeled off to form a plurality of fine voids, and the voids are formed to absorb impact energy and suppress the destruction of the matrix portion, which is caused by the liquid crystal polyester matrix. Fibrils (one of the main components of "microparticles") are produced.

The whiskers used in the present invention are not limited. It is preferable that the whiskers have an average diameter of 5 μm or less with toughness. Specifically, (i) potassium titanate (chemical formula: K ₂ O‧nTiO ₂ (n is 6 or 8), true specific gravity of 3.4 to 3.6, and average fiber diameter of 0.3 to 0.6 μm. For example, it is commercially available. Product name "Tismo" (manufactured by Otsuka Chemical Co., Ltd.); (ii) Calcium citrate (chemical formula: CaSiO ₃ , true specific gravity 2.5 to 2.6, fiber diameter 1 to 5 μm. For example, "silver stone (obtained from the market) Wollastonite)"); (iii) Calcium carbonate (chemical formula: CaCO ₃ , true specific gravity 2.8, average fiber diameter 0.5 to 1 μm. For example, the product name "WHISCAL" (manufactured by MARUO CALCIUM Co., Ltd.) can be obtained from the market); Iv) Zinc oxide (chemical formula: ZnO, true specific gravity 5.78, average fiber diameter 0.2 to 3 μm. For example, the product name "Panatetra" (manufactured by Panasonic Co., Ltd.) is available from the market); among these, from the mixing and stirring step From the viewpoint of ease of handling and ease of dispersion in the liquid crystal polyester constituting the matrix, it is preferable that the fiber diameter is large, and the difference in specific gravity from the liquid crystal polyester is small, and it is easy to achieve good dispersion (ii) and (iii). . These whiskers may be used singly or in combination of two or more kinds in any combination. In the resin composition of the present invention, the whisker content is preferably in the range of 10 to 30% by mass. If it is less than 10% by mass, the effect of addition is insufficient. If it exceeds 30% by mass, it is difficult to obtain good fluidity.

<precipitated barium sulfate>

The liquid crystal polyester resin composition of the present invention contains precipitated barium sulfate. Precipitated barium sulfate is a substantially spherical filler material, which has a low probability of causing interfacial peeling failure patterns of particle formation, and due to its specific high specific gravity (about 4.5), the impact energy of the liquid crystal polyester composition should be improved. The absorption efficiency is given to suppress the formation of microparticles. Moreover, it is amorphous, very fine, soft and not easily damaged, which should also be related to the inhibition of particle formation. When the precipitated barium sulfate is added to the resin composition of the present invention, the content thereof is preferably in the range of 3 to 20% by mass. If it is less than 3% by mass, the effect of addition is insufficient, and if it exceeds 20% by mass, it is difficult to obtain good fluidity.

<talc>

In the present invention, the liquid crystal polyester resin composition preferably contains talc. Since talc is a filling material having an ellipsoidal shape and a smooth surface, dimensional stability is imparted to the molded body by reducing anisotropy, so that the camera module component can improve particle particle detachment even under long-term use. Reliability and other reliability. When the talc is added to the resin composition of the present invention, the content thereof is preferably in the range of 5 to 20% by mass. If it is less than 5% by mass, the effect of addition is insufficient, and if it exceeds 20% by mass, it is difficult to obtain good fluidity.

<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 member, and is generally applicable to resin coloring, and is not particularly limited.

In the resin composition of the present invention, the content of carbon black is preferably in the range of 0.5 to 5% by mass. Further, it is preferably 2 to 4% by mass. When the blending amount of the carbon black is less than 0.5% by mass, the blackening property of the obtained resin composition is lowered, and the light-shielding property cannot be sufficiently ensured, and if it exceeds 5% by mass, the possibility of generation of particles (fine particles of carbon black-condensed fine particles) becomes variable. high.

Further, in the composition of the present invention, an antioxidant and a thermal stabilizer (for example, a hindered phenol, a hydroquinone, a phosphite, and the like) may be added to the extent that the object of the present invention is not impaired. , UV absorbers (such as resorcinol, salicylate, benzotriazole, benzophenone, etc.), slip agents and mold release agents (such as octadecanoic acid and its salts, esters, and parts thereof) Higher fatty acids such as esters and stearic acids and their salts, esters thereof, higher alcohols such as stearyl alcohol, stearin and polyethylene waxes and polyolefin waxes, etc., plasticizers, antistatic agents, flame retardants, etc. General additives, other filler materials other than the above, or other thermoplastic resins also impart predetermined characteristics. Further, the number of particles of the glass fiber is extremely large, which is not suitable for the purpose of the present invention (refer to the comparative example).

The liquid crystal polyester resin composition of the present invention is a molten liquid crystal polyester, which is obtained by mixing and stirring with other components, and is used for mixing and stirring a machine and a running method, and can be used as a general liquid crystal polyester melt mixing and stirring device, and There are no special restrictions.

Preferably, a liquid crystal polyester, whiskers, carbon black, and precipitated barium sulfate are placed in a mixing agitator having a pair of screws, and then talc is added as needed, and the mixture is melted, stirred, and pelletized.

This type of machine is called a two-axis extruder. In this type of machine, it is preferable to have a switching mechanism, which can uniformly disperse the filler material and suppress the local heat generation.

<Melt viscosity range>

In the present invention, the liquid crystal polyester resin composition thus obtained has a melt viscosity measured at a shear rate of 100 sec ^-1 and a melting point of +10 ° C of 20 to 100 Pa‧S, more preferably in the range of 30 to 80 Pa‧S. When the viscosity of the resin is out of this range, the surface properties of the injection molded body are deteriorated, and as a cause, it is feared that fine particles are generated. The melt viscosity was measured by a capillary rheometer (Model 2010) manufactured by INTESCO Co., Ltd., and the capillary was a capillary having a diameter of 1.00 mm, a length of 40 mm, and an inflow angle of 90° at a shear rate of 100 sec ^-1 and a melting point of -40 ° C to +4. At a temperature increase rate of ° C/min, the apparent viscosity was measured while heating at a constant speed, and the number of digits was rounded off to obtain the apparent viscosity at a melting point of +10 ° C.

<load deflection temperature>

Further, in the present invention, the weight deflection temperature of the injection molded body of the liquid crystal polyester resin composition thus obtained must be 220 ° C or higher. Here, the load deflection temperature means the load deflection temperature (DTUL) as determined by ASTM D648. If the load deflection temperature is lower than 220 ° C, it is unfavorable that the heat resistance at the time of solder reflow of the surface is problematic.

The resin composition of the present invention exhibits various characteristics and good fluidity of the constituent materials in the injection molding step, particularly in the molding of an injection molded body having a thin-walled structural portion having a thickness in the range of 0.3 to 0.9 mm. Provides camera module parts with good "particle breakaway resistance". In addition, the injection molded body used for injection molding may be any conventionally used for liquid crystal polyester molding, and is not particularly limited.

[Examples]

The present invention will be further specifically described by the following examples and comparative examples, but the present invention is not limited by the following examples.

The production example of the liquid crystal polyester (LCP) is shown below.

(Production Example: Production of Thermotropic Liquid Crystalline Polyester A)

SUS316 was used as a material, and a polymerization tank (manufactured by Kobe Steel Co., Ltd.) having a volume of 1700 liters of a herringbone impeller was charged with 298 kg (2.16 kmol) of p-hydroxybenzoic acid (manufactured by Ueno Pharmaceutical Co., Ltd.). , 4'-dihydroxybiphenyl (manufactured by Honshu Chemical Industry Co., Ltd.) 134kg (0.72 kmol), terephthalic acid (manufactured by Mitsui Chemicals, Inc.) 90kg (0.54 kmol), isophthalic acid ( 30 kg (0.18 kg) manufactured by AG International Chemical Co., Ltd., and a polymerization tank was charged with 0.04 kg of potassium acetate (manufactured by Kishida Chemical Co., Ltd.) and 0.10 kg of magnesium acetate (manufactured by Kishida Chemical Co., Ltd.) as a catalyst. The pressure-reducing-nitrogen injection was performed twice, and after nitrogen substitution, 386 kg (3.78 kg) of acetic anhydride was added, and the impellerization reaction was carried out under reflux at a stirring speed of 45 rpm for 1.5 hours. 2 hours. After the completion of the acetylation, the acetic acid was distilled off, and the temperature was raised at 0.5 ° C /min. When the reactor temperature was 305 ° C, the polymer was taken out from the discharge port at the lower portion of the reactor and cooled and solidified by a cooling device. The obtained polymer was pulverized into a sieve which passed through a pore of 2.0 mm by a pulverizer manufactured by Hosokawa Micron Co., Ltd. to obtain a prepolymer.

The obtained prepolymer was subjected to solid phase polymerization using a rotary kiln manufactured by Takasago Industrial Co., Ltd. The kiln was filled with a prepolymer, nitrogen was passed at a flow rate of ¹⁶ Nm ³ /hr, and the heater temperature was raised from room temperature to 350 ° C at a rotation speed of 2 rpm for 1 hour, and maintained at 350 ° C for 10 hours. It was confirmed that the temperature of the resin powder in the kiln reached 295 ° C, and the heating was stopped, and while rotating the rotary kiln, it was cooled for 4 hours to obtain a powdery liquid crystal polyester. The melting point is 360 ° C and the melt viscosity is 70 Pa‧S. Further, the melting point is measured in accordance with ISO11357-3 and ASTM D3418 (the same applies hereinafter).

(Manufacturing Example Manufacture of Thermotropic Liquid Crystal Polyester B)

The 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 Industrial Co., Ltd. The kiln was filled with a prepolymer, nitrogen was passed at a flow rate of ¹⁶ Nm ³ /hr, and the heater temperature was raised from room temperature to 350 ° C at a rotation speed of 2 rpm for 1 hour, and maintained at 350 ° C for 9 hours. It was confirmed that the temperature of the resin powder in the kiln reached 290 ° C, and the heating was stopped, and while rotating the rotary kiln, it was cooled for 4 hours to obtain a powdery liquid crystal polyester. The melting point is 350 ° C and the melt viscosity is 20 Pa ‧ S.

(Manufacturing Example Manufacture of Thermotropic Liquid Crystalline Polyester C)

The 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 Industrial Co., Ltd. The kiln was filled with a prepolymer, nitrogen was passed at a flow rate of ¹⁶ Nm ³ /hr, and the heater temperature was raised from room temperature to 350 ° C at a rotation speed of 2 rpm for 1 hour, and held at 350 ° C for 11 hours. It was confirmed that the temperature of the resin powder in the kiln reached 300 ° C, and the heating was stopped, and while rotating the rotary kiln, it was cooled for 4 hours to obtain a powdery liquid crystal polyester. The melting point is 370 ° C and the melt viscosity is 140 Pa ‧ S.

(Manufacturing Example Manufacture of Thermotropic Liquid Crystal Polyester D)

SUS316 was used as a material, and a polymerization tank (manufactured by Kobe Steel Co., Ltd.) having a volume of 1700 liters of a herringbone impeller was charged with 97.5 kg (1.43 kg) of p-hydroxybenzoic acid (manufactured by Ueno Pharmaceutical Co., Ltd.). 4,4'-dihydroxybiphenyl (manufactured by Honshu Chemical Industry Co., Ltd.) 71.7kg (0.385 kilograms) and terephthalic acid (manufactured by Mitsui Chemicals Co., Ltd.) 64.0kg (0.385 kilomoles) as a touch Into the medium, 0.06 kg of potassium acetate (manufactured by Kishida Chemical Co., Ltd.) and 0.10 kg of magnesium acetate (manufactured by Kishida Chemical Co., Ltd.) were placed, and the pressure-reduction nitrogen injection of the polymerization tank was performed twice. After nitrogen substitution, acetic anhydride 242.6 was added. Kg (2.4 kmol) was heated to 150 ° C for 1.5 hours with stirring impeller rotation speed, and acetonitrileization reaction was carried out for 2 hours under reflux. After the completion of the acetylation, the acetic acid was distilled off, and the temperature was raised at 0.5 ° C /min. When the reactor temperature was 305 ° C, the polymer was taken out from the discharge port at the lower portion of the reactor and cooled and solidified by a cooling device. The obtained polymer was pulverized into a sieve which passed through a pore of 2.0 mm by a pulverizer manufactured by Hosokawa Micron Co., Ltd. to obtain a prepolymer.

The obtained prepolymer was subjected to solid phase polymerization using a rotary kiln manufactured by Takasago Industrial Co., Ltd. The shape of the inner cylinder of the kiln is roughly a regular hexagonal shape with a length of 500 mm and a total length of 3,500 mm. The kiln was filled with 150 kg of a prepolymer, nitrogen was passed at a flow rate of 15 Nm ³ /hr, and the temperature in the heater was raised from room temperature to 400 ° C at 5 ° C for 5 hours, and held at 400 ° C for 12 hours. It was confirmed that the temperature of the pulverized material reached 340 ° C, and the heating was stopped, and while rotating the rotary kiln, it was cooled for 7 hours to obtain a wholly aromatic liquid crystal polyester resin D. The melting point is 380 ° C and the melt viscosity is 70 Pa ‧ S.

The characteristics of various fillers used in the examples and comparative examples of the present invention are shown below.

(1) Whiskers:

(i) Potassium titanate: chemical formula; K ₂ O‧nTiO ₂ :n is 6 or 8, true specific gravity is 3.4 to 3.6, and fiber diameter is 0.3 to 0.6 μm (trade name "Tismo", manufactured by Otsuka Chemical Co., Ltd.)

(ii) Calcium citrate: chemical formula; CaSiO ₃ , true specific gravity 2.5 to 2.6, average fiber diameter 1 to 5 μm (from the market name "Wollastonite")

(iii) Calcium carbonate: chemical formula; CaCO ₃ , true specific gravity 2.8, average fiber diameter 0.5 to 1 μm (trade name "WHISCAL", manufactured by MARUO CALCIUM Co., Ltd.)

(iv) Zinc oxide: chemical formula; ZnO, true specific gravity 5.78, average fiber diameter 0.2 to 3 μm (trade name "Panatetra", manufactured by Amtec Co., Ltd.)

(2) Carbon black (CB): manufactured by Cabot Co., Ltd., "REGAL 660" (first order particle size 24 nm)

(3) Precipitated barium sulfate: BChemical Industries, Ltd., "BMH-40" (average particle size 1 μm, specific gravity 4.5)

(4) Talc: manufactured by Japan Talc Co., Ltd., "MS-KY" (quantitative average particle size 23 μm)

(5) Glass fiber

Made by Nitto Spin Co., Ltd., PF100E-001SC (number average fiber length 100μm, number average fiber diameter 10μm)

(experiment method)

(1) Determination of melt viscosity

The melt viscosity of the thermotropic liquid crystal polyester resin composition was measured by a capillary rheometer (2010, manufactured by INTESCO Co., Ltd.), and a capillary having a diameter of 1.00 mm, a length of 40 mm, and an inflow angle of 90° was used at a shear rate of 100 sec ^{-1 .} The appearance viscosity was measured while heating at a constant temperature of +4 ° C / min (melting point -40 ° ° C), and the number of digits was rounded off to obtain the apparent viscosity at a melting point of +10 ° C. Test value. Further, the test was carried out using a resin composition which was previously dried in an air oven at 150 ° C for 4 hours.

(2) Strength measurement of the sintered portion

(test piece molding)

Using the injection molding machine (UH-1000, manufactured by Nissei Resin Co., Ltd.), the pellet of the obtained resin composition was obtained at a maximum cylinder temperature of 370 ° C, an injection speed of 300 mm/sec, and a mold temperature of 80 ° C to obtain a test piece. The injection of the resin was carried out at a 2-point gate. The mold is formed by a cavity having a size of 48 mm × 15 mm × 0.3 mm, which substantially collides with the melt wave front of the resin injected from different gates at the center to form a mold that spans the sintered portion of the molded body. Fig. 1 is a plan view and a side view showing the test piece obtained by the present mold.

(Fracture strength evaluation)

Five test pieces were prepared for each brand, and the resin frame was arranged such that both ends were located on the side of the frame, and the central portion having the sintered portion was placed in the frame window, and the two sides of the frame were adhered by adhesive tape. The end is fixed to the frame. The frame of the test piece was held by the adhesive, and after dropping 5 times from a height of 1.5 m, it was confirmed with a magnifying glass whether or not the sintered portion was broken. A test piece in which no crack occurred was regarded as "○", and a test piece in which cracking occurred was regarded as "x".

(3) Determination of load deflection temperature (DTUL)

Using the injection molding machine, the pellet of the obtained resin composition was obtained at a maximum cylinder temperature of 370 ° C, an injection speed of 100 mm/sec, and a mold temperature of 80 ° C to obtain an injection of 13 mm (width) × 130 mm (length) × 3 mm (thickness). The molded body was used as a test piece for measuring the deflection temperature of the load. For each test piece, the load deflection temperature was measured in accordance with ASTM D648. Based on the applicable surface adhesive work, 220 °C or more is regarded as "○", and less than 220 °C is regarded as "X".

(4) Determination of particle detachment resistance as a component of a camera module

(test piece molding)

Using the injection molding machine (UH-1000, manufactured by Nissei Resin Co., Ltd.), the pellet of the obtained resin composition was obtained at a maximum cylinder temperature of 370 ° C, an injection speed of 300 mm/sec, and a mold temperature of 80 ° C to obtain a test piece. The injection of the resin was carried out at a 1-point gate using a template having a circular recess of 6 mm in the center of a square shape of 8 mm, and a mold having a form of 3 mm in the center thereof. The minimum thickness is 0.9mm. Further, the window portion of the molded body corresponds to the lens insertion fixing portion of the actual camera module member, and the molded portion of the molded body inevitably generates a broken line portion. Fig. 2 is a plan view and a side view showing the test piece obtained by the mold.

(particle detachment resistance assessment)

The SUS container was housed in 50 test pieces, and the container lid was closed. After the container was dropped 50 times from a height of 1.5 m, the container lid was opened, and the test piece was separated from the particles dropped from the test piece, and the number of particles was calculated by "FPIA-3000" manufactured by Sysmex.

In the third stage, the evaluation of the particle detachment resistance is evaluated. When the number of generated particles is less than 100, it is regarded as "◎", and when it is 100 or more to less than 200, it is regarded as "○", and when it is more than 200, it is regarded as "X".

(5) Anisotropy evaluation

The difference in molding shrinkage ratio between the TD direction and the MD direction was evaluated. For each brand, five test pieces for measuring the "load deflection temperature" obtained in the above (3) were prepared, and after standing at room temperature for 24 hours or more, the length was measured as MD (molding) direction in units of mm. The width is measured as the TD (lateral side) direction to two decimal places. The average value of the dimensions was compared with the actual size of the mold ("length" = 130.02 mm, "width" = 13.02 mm), and the mold shrinkage ratio in the TD direction and the MD direction was determined.

The difference between the molding shrinkage ratio in the TD direction and the MD direction is less than 8 times as "○", and 8 times or more is regarded as "△".

[Table 1]

Industrial availability

The camera module member comprising the injection molded body of the wholly aromatic liquid crystal polyester resin composition of the present invention as a component assembly has heat resistance against solder reflow and is applicable to injection of a member having a thin portion. It is molded and, after being embedded in the product, it can be used in mobile phones, notebook computers, digital cameras, digital cameras, smart phones, and input-type terminals. The lens barrel and the pedestal holder can be used for various purposes such as "CMOS (image sensor) housing", "shutter and shutter tube".

Claims (3)

[Item 1] A wholly aromatic liquid crystal polyester resin composition characterized in that the total aromatic liquid crystal polyester is 50 to 80% by mass, the whiskers are 10 to 30% by mass, the carbon black is 0.5 to 5% by mass, and the talc is 0 to 20% by mass. And 3 to 20% by mass of the precipitated barium sulfate (100% by mass or more in total) obtained by mixing and stirring, the load deflection temperature is 220 ° C or more, and the shear rate is 100 sec ^-1 , (melting point + 10) ° C The melt viscosity at this time is 20 to 100 Pa‧S. [Item 2] The wholly aromatic liquid crystal polyester resin composition according to claim 1, wherein the whisker is at least one of calcium citrate and calcium carbonate having a true specific gravity of 3.0 or less. [Item 3] A camera module component comprising an injection molded body of the wholly aromatic liquid crystal polyester resin composition of the first or second aspect of the patent application as a constituent component.