JP2024051368A - Resin composition, molded article, camera module part, and camera module - Google Patents

Abstract

[Problem] To provide a resin composition that produces molded articles having low dust generation and excellent toughness, as well as good flowability and heat resistance, and a molded article made from the resin composition. [Solution] A resin composition containing a wholly aromatic polyester containing the following structural units (I), (II), (III), and (IV) as essential structural units, and a non-fibrous filler. JPEG2024051368000013.jpg67170Ar1 in (III) is 2,6-naphthalene or 4,4'-biphenylene. [Selected Figure] None

Description

The present invention relates to a resin composition, a molded article, a camera module component, and a camera module.

Liquid crystal resins such as fully aromatic polyesters have a good balance of excellent fluidity, mechanical strength, heat resistance, chemical resistance, and electrical properties, and are therefore used as materials for various electronic components. In recent years, liquid crystal resins have also been applied to precision instrument components, taking advantage of these characteristics.

Examples of such parts include connectors such as FPC connectors; sockets such as memory card sockets; camera module parts such as lens holders; relays, etc. Among these, efforts are being made to reduce size and improve precision, particularly in parts that hold optical lenses such as camera modules, by taking advantage of the properties of liquid crystal resins such as fluidity and mechanical strength.

In recent years, camera module parts have a problem in that the surfaces of the parts wear and generate dust due to sliding between parts caused by the addition of driving mechanisms such as zoom and focus adjustment and camera shake prevention, and due to impact collisions. In order to achieve low dust generation, it is possible to replace the resin with a resin that has high toughness and excellent impact resistance, such as nylon resin, but these resins are difficult to achieve the fluidity, dimensional stability, and heat resistance that liquid crystalline resins have. In response to this problem, for example, Patent Document 1 proposes a liquid crystalline polyester resin composition for camera modules in which spherical silica having a specific average particle size is blended with a liquid crystalline polyester resin, with the aim of providing a molded product with low dust generation, excellent toughness, and excellent impact strength.

International Publication No. 2017/077387

However, the liquid crystalline polyester resin composition of Patent Document 1 is insufficient in terms of low dust generation and toughness. In addition, it is difficult for conventional liquid crystalline resin compositions to simultaneously achieve all of the properties of low dust generation, toughness, fluidity, and heat resistance. Therefore, the present invention aims to provide a resin composition that can produce molded products that are excellent in low dust generation and toughness, and also have good fluidity and heat resistance, and a molded product thereof, as well as a camera module part and a camera module equipped with the camera module part.

As a result of intensive research, the present inventors have found that a resin composition that can solve all of the above-mentioned problems can be obtained by combining a wholly aromatic polyester containing a specific structural unit as an essential component with a non-fibrous filler, and have thus completed the present invention.
The present invention has the following aspects.
[1] A resin composition comprising:
The resin composition contains (A) a wholly aromatic polyester and (B) a non-fibrous filler,
The wholly aromatic polyester (A) contains, as essential components, the following structural units (I), (II), (III), and (IV):
Including,
Ar ₁ in the structural unit (III) represents 2,6-naphthalene or 4,4′-biphenylene;
The content of the structural unit (I) is 15 to 30 mol % based on all structural units,
The content of the structural unit (II) is 20 to 35 mol % based on all structural units,
The content of the structural unit (III) is 15 to 30 mol % based on all structural units,
The content of the structural unit (IV) is 20 to 35 mol % based on all structural units,
(B) the non-fibrous filler comprises at least one filler selected from the group consisting of plate-like fillers and granular fillers having a median diameter of 50 μm or less;
(A) the content of the wholly aromatic polyester is 60 to 90% by mass based on the total mass of the resin composition,
(B) A resin composition having a non-fibrous filler content of 10 to 40 mass% based on the total mass of the resin composition.
[2] The resin composition according to [1], wherein the total content of the structural units (I) to (IV) is 90 to 100 mol% based on all structural units of the wholly aromatic polyester (A).
[3] The wholly aromatic polyester (A) further comprises the following structural unit (V):
Including,
The resin composition according to [1] or [2], wherein the total content of the structural units (I), (II) and (V) is 47.5 to 52.5 mol% based on all structural units.
[4] The wholly aromatic polyester (A) further comprises the following structural unit (VI):
Including,
The resin composition according to any one of [1] to [3], wherein the total content of the structural units (III), (IV) and (VI) is 47.5 to 52.5 mol% based on all structural units.
[5] The resin composition according to any one of [1] to [4], wherein the non-fibrous filler (B) comprises at least one selected from the group consisting of talc, mica, silica and barium sulfate.
[6] The resin composition further comprises (C) an epoxy group-containing polymer,
(A) the content of the wholly aromatic polyester is 60 to 87.5% by mass based on the total mass of the resin composition,
(B) the content of the non-fibrous filler is 10 to 37.5% by mass based on the total mass of the resin composition;
The resin composition according to any one of [1] to [5], wherein the content of the epoxy group-containing polymer (C) is 1 to 7 mass% based on the total mass of the resin composition.
[7] The resin composition according to any one of [1] to [6], which is for use in a camera module component.
[8] Use of the resin composition according to any one of [1] to [6] for producing a camera module component.
[9] A molded article comprising the resin composition according to any one of [1] to [6].
[10] The molded product according to [9], which is a camera module part.
[11] A camera module comprising the camera module component according to [10].

The present invention can provide a resin composition that produces molded articles that have low dust generation and excellent toughness, as well as good fluidity and heat resistance, and a molded article made from the resin composition, as well as a camera module part and a camera module that includes the camera module part.

FIG. 1 is a cross-sectional view illustrating a typical camera module.

One embodiment of the present invention is described in detail below. The present invention is not limited to the following embodiment, and can be implemented by making appropriate modifications within the scope that does not impair the effects of the present invention. When a specific description given for one embodiment also applies to other embodiments, the description may be omitted in other embodiments. In this disclosure, the expression "X to Y" for a numerical range means "X or more and Y or less."

[Resin composition]
The resin composition according to the present embodiment contains (A) a wholly aromatic polyester and (B) a non-fibrous filler. The wholly aromatic polyester (A) contains, as essential components, the following structural units (I), (II), (III), and (IV):
Ar ₁ in the structural unit (III) represents 2,6-naphthalene or 4,4'-biphenylene; the content of the structural unit (I) is 15 to 30 mol% based on all structural units; the content of the structural unit (II) is 20 to 35 mol% based on all structural units; the content of the structural unit (III) is 15 to 30 mol% based on all structural units; the content of the structural unit (IV) is 20 to 35 mol% based on all structural units; (B) the non-fibrous filler comprises at least one filler selected from the group consisting of plate-like fillers and granular fillers having a median diameter of 50 μm or less; (A) the content of the wholly aromatic polyester is 60 to 90 mass% based on the total mass of the resin composition; and (B) the content of the non-fibrous filler is 10 to 40 mass% based on the total mass of the resin composition. In the resin composition according to the present embodiment, the total content of the (A) wholly aromatic polyester and the (B) non-fibrous filler does not exceed 100% by mass. In addition, in the present disclosure, the proportion (mol%) of each structural unit of the (A) component can be calculated from the monomer charge ratio when polymerizing the (A) component. Alternatively, the proportion (mol%) of each structural unit of the (A) component can also be calculated by the pyrolysis gas chromatography method described in Polymer Degradation and Stability vol. 76 (2002), 85-94.
The resin composition according to this embodiment can provide a molded article that has excellent low dust generation and toughness, as well as good flowability and heat resistance.

<(A) Wholly Aromatic Polyester>
The resin composition according to the present embodiment contains (A) a wholly aromatic polyester (hereinafter, also referred to as "component (A)"). Component (A) contains the following structural units (I), (II), (III), and (IV) as essential components.

The structural unit (I) is derived from 1,4-phenylenedicarboxylic acid (hereinafter sometimes referred to as "TA") and its polymerizable derivatives. Examples of the polymerizable derivatives include alkyl esters (the alkyl group preferably has about 1 to 4 carbon atoms) and halides of 1,4-phenylenedicarboxylic acid. In this embodiment, the (A) component contains 15 to 30 mol% of the structural unit (I) relative to the total structural units. If the content of the structural unit (I) is 15 to 30 mol%, the toughness of the molded product obtained will be high and the heat resistance will also be good. From the viewpoint of making it easier to achieve both the toughness and heat resistance of the molded product obtained, the content of the structural unit (I) relative to the total structural units is preferably 15 to 28.75 mol%, more preferably 15 to 27.5 mol%, and even more preferably 17.5 to 26 mol%.

The structural unit (II) is derived from 2,6-naphthalenedicarboxylic acid (hereinafter sometimes referred to as "NDA") and its polymerizable derivatives. Examples of the polymerizable derivatives include alkyl esters (preferably alkyl groups having 1 to 4 carbon atoms) and halides of 2,6-naphthalenedicarboxylic acid. In this embodiment, component (A) contains 20 to 35 mol% of structural unit (II) relative to the total structural units. If the content of structural unit (II) is 20 to 35 mol%, the toughness of the molded article obtained will be high and the heat resistance will also be good. From the viewpoint of making it easier to achieve both the toughness and heat resistance of the molded article obtained, the content of structural unit (II) relative to the total structural units is preferably 21.25 to 35 mol%, more preferably 22.5 to 35 mol%, and even more preferably 24 to 32.5 mol%.

In the structural unit (III), Ar ₁ represents 2,6-dihydroxynaphthalene (hereinafter, sometimes referred to as "NDO") or 4,4'-dihydroxybiphenyl (hereinafter, sometimes referred to as "BP"). That is, the structural unit (III) may be a unit derived from NDO and a polymerizable derivative thereof, may be a unit derived from BP and a polymerizable derivative thereof, or may contain two or more of these. In addition, examples of polymerizable derivatives of NDO include alkyl esters (the alkyl group preferably has about 1 to 4 carbon atoms) or halides of 2,6-dihydroxynaphthalene. In addition, examples of polymerizable derivatives of BP include alkyl esters (the alkyl group preferably has about 1 to 4 carbon atoms) or halides of 4,4'-dihydroxybiphenyl.

In one embodiment, from the standpoint of cost and availability, it is preferable that the structural unit (III) contains a unit derived from BP.

In this embodiment, component (A) contains 15 to 30 mol% of the structural unit (III) relative to all structural units. If the content of structural unit (III) is 15 to 30 mol%, the toughness of the resulting molded article will be high and the heat resistance will also be good. From the viewpoint of making it easier to achieve both toughness and heat resistance in the resulting molded article, the content of structural unit (III) relative to all structural units is preferably 15 to 28.75 mol%, more preferably 15 to 27.5 mol%, and even more preferably 17.5 to 26 mol%.

The structural unit (IV) is derived from 1,4-dihydroxybenzene (hereinafter sometimes referred to as "HQ") and its polymerizable derivatives. Examples of the polymerizable derivatives include alkyl esters (the alkyl group preferably has about 1 to 4 carbon atoms) and halides of 1,4-dihydroxybenzene. In this embodiment, component (A) contains 20 to 35 mol% of the structural unit (IV) relative to the total structural units. If the content of structural unit (IV) is 20 to 35 mol%, the toughness of the molded article obtained will be high and the heat resistance will also be good. From the viewpoint of making it easier to achieve both the toughness and heat resistance of the molded article obtained, the content of structural unit (IV) is preferably 21.25 to 35 mol%, more preferably 22.5 to 35 mol%, and even more preferably 24 to 32.5 mol%.

In one embodiment, the total content of the structural units (I) to (IV) in the (A) component is preferably 90 to 100 mol %, and more preferably 95 to 100 mol %, based on all the structural units in the (A) component. From the viewpoint of making it easier to obtain a molded product with higher toughness and excellent heat resistance, the (A) component may contain only the structural units (I) to (IV) (i.e., the total content of the structural units (I) to (IV) may be 100 mol % based on all the structural units).

The component (A) may contain a structural unit other than the above-mentioned structural units (I) to (IV). In one embodiment, the component (A) may contain the following structural unit (V).

The structural unit (V) is derived from 1,3-phenylenedicarboxylic acid (hereinafter sometimes referred to as "IA") and its polymerizable derivatives. Examples of the polymerizable derivatives include alkyl esters (preferably the alkyl group has about 1 to 4 carbon atoms) and halides of 1,3-phenylenedicarboxylic acid. When component (A) contains structural unit (V), the total content of structural units (I), (II), and (V) derived from aromatic dicarboxylic acid is preferably 47.5 to 52.5 mol%, more preferably 48.75 to 51.25 mol%, and particularly preferably 50 mol%, based on the total structural units. When component (A) contains structural unit (V), the melting point of component (A) is easily lowered, and a wholly aromatic polyester that is easier to handle is easily obtained.

In one embodiment, when component (A) contains structural unit (V), the content of structural unit (V) is preferably 0.5 to 10 mol%, more preferably 0.5 to 7.5 mol%, and even more preferably 0.5 to 5 mol% relative to the total structural units of component (A). As described above, the total content of structural units (I), (II) and (V) is preferably in the range of 47.5 to 52.5 mol%. That is, when component (A) contains structural unit (V), it is preferable to replace a portion of structural unit (I) and/or structural unit (II) with structural unit (V). By replacing a portion of structural unit (I) and/or structural unit (II) with structural unit (V), the melting point of component (A) is easily lowered and the handling property is easily improved. In one embodiment, the molar ratio ((I)/(II)/(V)) of the structural units (I), (II) and (V) in the component (A) may be (15-30)/(20-35)/(0-10), (15-28.75)/(21.25-35)/(0.5-10), or (15-27.5)/(22.5-35)/(0.5-7.5).

In one embodiment, the component (A) may contain the following structural unit (VI).

The structural unit (VI) is derived from 1,3-dihydroxybenzene (common name: resorcinol, hereinafter sometimes referred to as "RES") and its polymerizable derivatives. Examples of the polymerizable derivatives include alkyl esters (preferably alkyl groups having about 1 to 4 carbon atoms) and halides of 1,3-dihydroxybenzene. When component (A) contains structural unit (VI), the total content of structural units (III), (IV) and (VI) derived from aromatic diol is preferably 47.5 to 52.5 mol %, more preferably 48.75 to 51.25 mol %, and particularly preferably 50 mol %, based on the total structural units. When component (A) contains structural unit (VI), the melting point of component (A) is easily lowered, and a wholly aromatic polyester that is easier to handle is easily obtained.

In one embodiment, when component (A) contains structural unit (VI), the content of structural unit (VI) is preferably 0.5 to 10 mol%, more preferably 0.5 to 7.5 mol%, and even more preferably 0.5 to 5 mol% relative to the total structural units of component (A). As described above, the total content of structural units (III), (IV) and (VI) is preferably in the range of 47.5 to 52.5 mol%. That is, when component (A) contains structural unit (VI), it is preferable to replace a part of structural unit (III) and/or structural unit (IV) with structural unit (VI). By replacing a part of structural unit (III) and/or structural unit (IV) with structural unit (VI), the melting point of component (A) is easily lowered and the handling property is easily improved. In one embodiment, the molar ratio ((III)/(IV)/(VI)) of the structural units (III), (IV) and (VI) in the component (A) may be (15-30)/(20-35)/(0-10), (15-28.75)/(21.25-35)/(0.5-10), or (15-27.5)/(22.5-35)/(0.5-7.5).

It is preferable that component (A) does not contain structural units derived from aromatic hydroxycarboxylic acids (e.g., p-hydroxybenzoic acid (hereinafter sometimes referred to as "HBA"), 6-hydroxy-2-naphthoic acid (hereinafter sometimes referred to as "HNA"), etc.). If it does not contain structural units derived from aromatic hydroxycarboxylic acids, it becomes easier to obtain molded products with superior toughness.

In one embodiment, the molar ratio of the units derived from aromatic dicarboxylic acid (the total amount of structural units (I), (II), and (V)) to the units derived from aromatic diol (the total amount of structural units (III), (IV), and (VI)) in component (A) is preferably in the range of 1.05:1 to 1:1.05.

The content of the (A) wholly aromatic polyester in the resin composition according to this embodiment is 60 to 90 mass % relative to the total mass of the resin composition, preferably 62.5 to 85 mass %, more preferably 65 to 80 mass %, and even more preferably 67 to 75 mass %. If the content of the (A) wholly aromatic polyester in the resin composition is within the above range, a molded product having good flowability during molding and excellent toughness and heat resistance can be obtained.

In one embodiment, the component (A) is preferably a liquid crystalline resin that exhibits optical anisotropy when melted. When the component (A) is a liquid crystalline resin, it becomes easier to obtain a resin composition that has both fluidity and toughness.
The fact that the resin exhibits optical anisotropy when melted can be confirmed by a conventional polarization inspection method using crossed polarizers. More specifically, the optical anisotropy of the component (A) can be confirmed by using a polarizing microscope (e.g., Olympus Corporation, product name: BX51), melting a sample placed on a hot stage (e.g., Linkam Corporation, product name: CSS450), and observing the sample at a magnification of 150 times under a nitrogen atmosphere. The liquid crystal resin is optically anisotropic, and transmits light when inserted between crossed polarizers. If the sample is optically anisotropic, polarized light will be transmitted even when the sample is in a molten, stationary liquid state, for example.

Nematic liquid crystal resins experience a significant drop in viscosity above their melting point, so the ability to exhibit liquid crystallinity at or above the melting point is generally an indicator of processability.

In one embodiment, the melt viscosity of component (A) at a temperature 10 to 40°C higher than the melting point of component (A) and at a shear rate of 1000/sec is preferably 1000 Pa·s or less, more preferably 4 to 500 Pa·s, even more preferably 4 to 250 Pa·s, and particularly preferably 5 to 100 Pa·s. When the melt viscosity of component (A) is within the above range, fluidity is easily ensured during molding of the resin composition according to this embodiment, and the filling pressure is unlikely to become excessive. In this disclosure, melt viscosity refers to the melt viscosity measured in accordance with ISO 11443.

In one embodiment, the flow initiation temperature of component (A) is preferably 310°C or less, more preferably 300°C or less, and even more preferably 295°C or less. If the flow initiation temperature is 310°C or less, it is likely to become a liquid crystalline wholly aromatic polyester with excellent melt processability at low temperatures. In one embodiment, component (A) may have a flow initiation temperature of 292°C or less. In another embodiment, component (A) may have a flow initiation temperature of 290°C or less or 280°C or less.

The flow initiation temperature is the temperature at which component (A) becomes fluid when heated by an external force, and can be measured by the following method. That is, the flow initiation temperature is measured using a capillary rheometer (for example, product name "Flow Tester CFT-500" manufactured by Shimadzu Corporation) as the temperature (°C) at which a melt viscosity of 48,000 poise is exhibited when a sample resin heated and melted at a heating rate of 4°C/min is extruded under a load of 100 kg/ ^cm2 from a nozzle having an inner diameter of 1 mm and a length of 10 mm.

<(A) Method for producing wholly aromatic polyester>
Next, the method for producing the wholly aromatic polyester (A) will be described.
The wholly aromatic polyester (A) contained in the resin composition according to this embodiment can be produced by a method including acylation of an aromatic diol component with a fatty acid anhydride, followed by polycondensation with an aromatic dicarboxylic acid component.
The aromatic diol component includes at least one selected from 4,4'-dihydroxybiphenyl (BP) and 2,6-dihydroxynaphthalene (NDO), and 1,4-dihydroxybenzene (HQ). The aromatic dicarboxylic acid component includes 1,4-phenylenedicarboxylic acid (TA) and 2,6-naphthalenedicarboxylic acid (NDA).

In one embodiment, the aromatic diol component may include at least one selected from BP and NDO, HQ, and resorcinol (RES). In one embodiment, the aromatic dicarboxylic acid component may include TA, NDA, and 1,3-phenylenedicarboxylic acid (IA). Each of TA, IA, NDA, BP, NDO, HQ, and RES may include a polymerizable derivative thereof. Examples of the polymerizable derivative include the aforementioned alkyl esters (the alkyl group preferably has about 1 to 4 carbon atoms) and halides.

(Acylating Agent)
The fatty acid anhydride acts as an acylating agent. Examples of the fatty acid anhydride include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, pivalic anhydride, 2-ethylhexanoic anhydride, monochloroacetic anhydride, dichloroacetic anhydride, trichloroacetic anhydride, monobromoacetic anhydride, dibromoacetic anhydride, tribromoacetic anhydride, monofluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, glutaric anhydride, maleic anhydride, succinic anhydride, and β-bromopropionic anhydride. It is preferable to use at least one fatty acid anhydride selected from these.

From the viewpoint of cost and ease of handling, preferred are carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, butyric anhydride, and isobutyric anhydride, and it is preferable to use at least one selected from these. Among these, it is preferable that the fatty acid anhydride contains acetic anhydride from the viewpoint of ease of availability.

In terms of ease of reaction control, the amount of fatty acid anhydride used is preferably 1.0 to 1.1 equivalents relative to the total amount of hydroxyl groups in the aromatic diol component (i.e., the total amount of hydroxyl groups in the aromatic diol component containing at least one selected from BP and NDO, HQ, and, if necessary, RES), and more preferably 1.01 to 1.05 equivalents.

The total amount of at least one selected from BP and NDO used is 15 to 30 mol%, preferably 15 to 28.75 mol%, more preferably 15 to 27.5 mol%, and even more preferably 17.5 to 26 mol%, based on the total monomers constituting component (A). In one embodiment, the total amount of BP and NDO used may be 18 to 26 mol%, 19 to 25.5 mol%, or 20 to 25 mol%, based on the total monomers.

The amount of HQ used is 20 to 35 mol% relative to the total monomers constituting component (A), preferably 21.25 to 35 mol%, more preferably 22.5 to 35 mol%, and even more preferably 24 to 32.5 mol%. In one embodiment, the amount of HQ used may be 24.5 to 32 mol%, 24.5 to 31 mol%, or 25 to 30 mol% relative to the total monomers.

When preparing component (A) containing structural unit (V), RES can be included as the aromatic diol component. RES can be blended so that the total amount of at least one selected from BP and NDO, HQ, and RES used is 47.5 to 52.5 mol% based on all monomers constituting component (A). The total amount used is preferably 48.75 to 51.25 mol%, particularly preferably 50 mol%, based on all monomers.

Acylation can be carried out by known methods. For example, at least one selected from BP and NDO, HQ, and optionally RES may be mixed with a fatty acid anhydride and heated at a temperature range of 120 to 160°C for about 0.5 to 5 hours to obtain a reaction product containing an acylated product.

(Polycondensation reaction)
Next, the acylated product obtained by the acylation is polycondensed with TA and NDA. In one embodiment, the acylated product may be polycondensed with TA, NDA, and IA.

The amount of TA used is 15 to 30 mol%, preferably 15 to 28.75 mol%, more preferably 15 to 27.5 mol%, and even more preferably 17.5 to 26 mol%, based on the total monomers constituting component (A). In one embodiment, the amount of TA used may be 18 to 26 mol%, 19 to 25.5 mol%, or 20 to 25 mol%, based on the total monomers.

The amount of NDA used is 20 to 35 mol% relative to the total monomers constituting component (A), preferably 21.25 to 35 mol%, more preferably 22.5 to 35 mol%, and even more preferably 24 to 32.5 mol%. In one embodiment, the amount of NDA used may be 24.5 to 32 mol%, 24.5 to 31 mol%, or 25 to 30 mol% relative to the total monomers.

When preparing component (A) containing structural unit (VI), IA can be included as the aromatic dicarboxylic acid component. IA can be blended so that the total amount of TA, NDA, and IA used is 47.5 to 52.5 mol% based on all monomers constituting component (A). The total amount used is preferably 48.75 to 51.25 mol%, particularly preferably 50 mol%, based on all monomers.

The polycondensation reaction can be carried out by a known method. For example, an acylation product of at least one selected from BP and NDO with HQ (including an acylation product of RES as necessary) is mixed with TA and NDA (including IA as necessary), and the mixture is heated in the temperature range of 200 to 400°C for about 2 to 12 hours to cause polycondensation.

In one embodiment, the total amount of at least one selected from TA, NDA, BP, and NDA, and HQ used is preferably 90 to 100 mol%, and more preferably 95 to 100 mol%, based on the total monomers constituting component (A). The total amount used may be 100 mol%.

In the polycondensation reaction, a melt polymerization method, a solution polymerization method, a slurry polymerization method, a solid-phase polymerization method, or a combination of two or more of these methods is used, and the melt polymerization method or a combination of the melt polymerization method and the solid-phase polymerization method is preferably used.

The wholly aromatic polyester (A) produced by the above polycondensation reaction can be further subjected to solid-phase polymerization in which the polyester is heated in an inert gas under normal pressure or reduced pressure to increase the molecular weight.
The solid-phase polymerization can be carried out by a conventional method. For example, the solid-phase polymerization can be carried out by heating the raw material resin (the wholly aromatic polyester obtained by the polycondensation reaction) at a temperature 10 to 120° C. lower than the liquid crystal formation temperature of the raw material resin (the wholly aromatic polyester obtained by the polycondensation reaction) under reduced pressure or vacuum in an inert gas flow such as nitrogen gas. Since the melting point of the wholly aromatic polyester increases as the solid-phase polymerization proceeds, it is also possible to carry out the solid-phase polymerization at a temperature equal to or higher than the original melting point of the raw material resin. The solid-phase polymerization can be carried out at a constant temperature or can be increased stepwise. The heating method is not particularly limited, and microwave heating, heater heating, etc. can be used.

A known catalyst can be used in each of the above reactions. Representative examples 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), and organic compound catalysts such as 1-methylimidazole and 4-dimethylaminopyridine. It is preferable that the catalyst contains at least one selected from these. The same catalyst may be used in the acylation reaction and the polycondensation reaction (if necessary, the solid-state polymerization reaction).

In each of the above reactions, all the raw material monomers, fatty acid anhydride, and catalyst can be charged into the same reaction vessel and the reaction can be started (single-stage method), or the aromatic diol component mentioned above can be acylated with the fatty acid anhydride and then reacted separately with the aromatic dicarboxylic acid component mentioned above (two-stage method).

<(B) Non-fibrous filler>
The resin composition according to the present embodiment includes a non-fibrous filler (B). The non-fibrous filler (B) (hereinafter, sometimes referred to as "component (B)") refers to a plate-like or granular filler. In the resin composition according to the present embodiment, component (B) includes at least one filler selected from the group consisting of plate-like fillers and granular fillers having a median diameter of 50 μm or less. By combining component (A) with component (B), the resin composition according to the present embodiment can obtain a molded product having excellent low dust generation and toughness, as well as good fluidity and heat resistance. In this disclosure, the median diameter refers to the volume-based median particle diameter (D50) measured by a laser diffraction/scattering method. Specifically, it refers to a value measured using a laser diffraction/scattering particle size distribution measuring device (for example, manufactured by Horiba, Ltd., product name: laser diffraction/scattering particle size distribution measuring device LA-920).

(Plate-like filler)
Component (B) may contain a plate-like filler having a median diameter of 50 μm or less. The median diameter of the plate-like filler is preferably 5 to 50 μm, more preferably 5 to 40 μm, and even more preferably 10 to 40 μm. The median diameter of the plate-like filler may be 10 to 25 μm. When component (B) contains a plate-like filler, as long as the median diameter of the plate-like filler is within the above range, the fluidity of the resin composition is prevented from decreasing, and the toughness of the molded product is more likely to be improved.

Examples of plate-like fillers include talc, mica, glass flakes, and various metal foils. These may be used alone or in combination of two or more. Of these, it is preferable to include at least one selected from the group consisting of talc and mica, from the viewpoint of improving the toughness of the resulting molded product without deteriorating the fluidity of the resin composition and of making it easier to achieve low dust generation.

(talc)
Examples of talc _{that can be preferably used as component (B) include talc having a total content of Fe2O3, Al2O3, and CaO of 2.5% by mass or less, a total content of Fe2O3 and Al2O3 of more than} 1.0% by mass and 2.0% by mass or less, and a CaO content of less than 0.5% by mass, relative to the total solid content of the _talc . That is, the talc may contain at least one of _Fe2O3 , _Al2O3 , and CaO in addition to _SiO2 and _MgO , which are the _main components _, and each component may be contained within the above content range.

In addition, in the above talc, if the total content of Fe ₂ O ₃ , Al ₂ O ₃ and CaO is 2.5 mass% or less, the moldability of the resin composition and the heat resistance of the obtained molded product are unlikely to deteriorate. In one embodiment, the total content of Fe ₂ O ₃ , Al ₂ O ₃ and CaO is more preferably 1.0 to 2.0 mass%.

In addition, among the above talc, those having a total content of _Fe2O3 and _Al2O3 of more than 1.0% by mass and not more than 2.0% by mass _are more easily available, _and the molding processability of the resin composition and the heat resistance of the obtained molded article are less likely to deteriorate. In one embodiment, the total content of _Fe2O3 and _Al2O3 of the talc is more preferably more than 1.0% _by mass and not more than 1.7% _by mass.

In one embodiment, the CaO content in the talc is preferably less than 0.5% by mass. If the CaO content is less than 0.5% by mass, the moldability of the resin composition and the heat resistance of the resulting molded product are less likely to deteriorate. In one embodiment, the CaO content of the talc is more preferably 0.01 to 0.4% by mass.

(Mica)
Mica refers to a pulverized silicate mineral containing aluminum, potassium, magnesium, sodium, iron, etc. Examples of mica that can be preferably used as component (C) include muscovite, phlogopite, biotite, and artificial mica, and among these, muscovite is preferred because of its good hue and low cost.

There are no particular limitations on the method for producing mica, but mica obtained by a wet grinding method is preferred from the viewpoint that it is easier to obtain mica with the desired median diameter and thickness.

(Granular filler)
The (B) component may contain a granular filler having a median diameter of 50 μm or less. The median diameter of the granular filler is preferably 0.1 to 20 μm, more preferably 0.1 to 10 μm, and even more preferably 0.5 to 10 μm. When the granular filler is contained, if the median diameter of the granular filler is within the above range, the fluidity of the resin composition is prevented from decreasing, and the toughness of the molded product is more likely to be improved. Examples of the granular filler include silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, wollastonite and other silicates; iron oxide, titanium oxide, zinc oxide, alumina and other metal oxides; calcium carbonate, magnesium carbonate and other metal carbonates; calcium sulfate, barium sulfate and other metal sulfates; silicon carbide; silicon nitride; boron nitride and the like. These may be used alone or in combination of two or more. Among these, from the viewpoint of more easily improving the toughness of the obtained molded article and easily achieving low dust generation without deteriorating the fluidity of the resin composition, it is preferable to contain at least one selected from silicates and metal sulfates, and it is more preferable to contain at least one selected from silica and barium sulfate.

In one embodiment, component (B) preferably contains at least one filler selected from the group consisting of talc, mica, silica, and barium sulfate, and more preferably contains talc or mica.

The content of component (B) in the resin composition is 10 to 40 mass% relative to the total mass of the resin composition, preferably 10 to 35 mass%, more preferably 15 to 35 mass%, even more preferably 15 to 30 mass%, and particularly preferably 20 to 30 mass%. In one embodiment, the content of component (B) may be 10 to 25 mass% or may be 10 to 20 mass% relative to the total mass of the resin composition. If the content of component (B) is within the above range, it is easy to achieve low dust generation, toughness, and heat resistance in the obtained molded product.

<(C) Epoxy Group-Containing Polymer>
In one embodiment, the resin composition may further include an epoxy group-containing polymer (C). The epoxy group-containing polymer (C) (hereinafter, sometimes referred to as "component (C)") may be used alone or in combination of two or more kinds.
The component (C) is not particularly limited as long as it has the effects of the present invention, and examples thereof include at least one selected from the group consisting of (C1) an epoxy group-containing olefin polymer and (C2) an epoxy group-containing styrene polymer. By including the component (C), the low dust generation properties of the molded article obtained from the resin composition according to the present embodiment tend to be improved.

((C1) Epoxy Group-Containing Olefin Polymer)
In one embodiment, the component (C) can include an epoxy group-containing olefin polymer (C1). Examples of the epoxy group-containing olefin polymer (C1) (hereinafter, sometimes referred to as "component (C1)") include copolymers composed of repeating units derived from an α-olefin and repeating units derived from a glycidyl ester of an α,β-unsaturated acid.

The α-olefin is not particularly limited, and examples thereof include ethylene, propylene, butene, and among these, ethylene is preferably used.
The glycidyl ester of an α,β-unsaturated acid is a compound represented by the following general formula (1). In the following general formula (1), R' represents hydrogen, a lower alkyl group having 1 to 5 carbon atoms, or a -R ¹ -COOH group (R ¹ represents an alkylene group having 1 to 5 carbon atoms). Of these, the glycidyl ester of an α,β-unsaturated acid is preferably acrylic acid glycidyl ester, methacrylic acid glycidyl ester, ethacrylic acid glycidyl ester, or itaconic acid glycidyl ester. From the viewpoint of more favorable low dust generation properties, it is particularly preferable to contain methacrylic acid glycidyl ester.

In one embodiment, the content of repeating units derived from α-olefins in component (C1) is preferably 87 to 98% by mass, more preferably 90 to 97% by mass, based on all structural units of component (C1). The content of repeating units derived from glycidyl esters of α,β-unsaturated acids is preferably 2 to 13% by mass, more preferably 3 to 10% by mass, based on all structural units. The content can be calculated from ¹ H-NMR measurement or the like.

In one embodiment, component (C1) may contain, in addition to the above two components, a repeating unit derived from one or more olefin-based unsaturated esters such as acrylonitrile, acrylic acid esters, methacrylic acid esters, α-methylstyrene, and maleic anhydride as a third component, within a range that does not impair the effects of the present invention. When a third component is contained, it may be contained in an amount of 0 to 48 parts by mass relative to the total amount (100 parts by mass) of the above two components.

Component (C1) can be prepared by a normal radical polymerization method using monomers corresponding to each of the aforementioned components and a radical polymerization catalyst. Specifically, it can be produced by copolymerizing an α-olefin and a glycidyl ester of an α,β-unsaturated acid in the presence of a radical polymerization catalyst at 500 to 4000 atm and 100 to 300°C. The polymerization may be carried out in the presence or absence of a solvent or a chain transfer agent. Alternatively, it can be produced by mixing an α-olefin, a glycidyl ester of an α,β-unsaturated acid, and a radical polymerization catalyst, and melt-graft-copolymerizing the mixture in an extruder.

((C2) Epoxy Group-Containing Styrene-Based Polymer)
In one embodiment, the component (C) can contain an epoxy group-containing styrene-based polymer (C2) (hereinafter, sometimes referred to as "component (C2)"). Examples of the component (C2) include a copolymer composed of a repeating unit derived from a styrene and a repeating unit derived from a glycidyl ester of an α,β-unsaturated acid. Examples of the glycidyl ester of an α,β-unsaturated acid include the same as those for the component (C1), and preferred examples are also the same.

Examples of styrenes include styrene, α-methylstyrene, halogenated styrenes (e.g., brominated styrene, etc.), and divinylbenzene. Of these, styrene is preferably used.

In one embodiment, the (C2) component may be a multicomponent copolymer containing, in addition to the above two components, a repeating unit derived from one or more other vinyl monomers as a third component, within a range that does not impair the effects of the present invention. A suitable third component is a repeating unit derived from one or more olefin-based unsaturated esters such as acrylonitrile, acrylic acid esters, methacrylic acid esters, and maleic anhydride. As the (C2) component, an epoxy group-containing styrene-based polymer containing 40 mass% or less of the repeating unit derived from the third component in the copolymer is preferred.

In one embodiment, the content of repeating units derived from a glycidyl ester of an α,β-unsaturated acid in component (C2) is preferably 2 to 20% by mass relative to all structural units of component (C2). The content of repeating units derived from styrenes is preferably 80 to 98% by mass relative to all structural units. The content can be calculated from ¹ H-NMR measurement or the like.

Component (C2) can be prepared by a normal radical polymerization method using monomers corresponding to each of the aforementioned components and a radical polymerization catalyst. Specifically, it can be produced by copolymerizing styrenes and glycidyl esters of α,β-unsaturated acids in the presence of a radical polymerization catalyst at 500 to 4000 atm and 100 to 300°C. The polymerization may be carried out in the presence or absence of a solvent or a chain transfer agent. Alternatively, it can be produced by mixing α-olefins, glycidyl esters of α,β-unsaturated acids, and a radical polymerization catalyst, and melt-graft-copolymerizing them in an extruder.

In one embodiment, from the viewpoint of making the heat resistance of the obtained molded article more favorable, it is preferable that the component (C) contains the component (C1).
When the components (C1) and (C2) are used in combination, the ratio of these components can be appropriately selected according to the required properties.

In one embodiment, the content of component (C) in the resin composition is preferably 1 to 7 mass %, more preferably 1.5 to 6.5 mass %, and even more preferably 2 to 6 mass %, based on the total mass of the resin composition. If the content of component (C) is within the above range, it is preferable because the low dust generation is improved without impairing physical properties such as toughness, heat resistance, and fluidity.

(Other ingredients)
The resin composition according to the present embodiment may contain other components such as a nucleating agent, a pigment such as carbon black or inorganic calcined pigment, an antioxidant, a stabilizer, a plasticizer, a lubricant, a release agent, a flame retardant, and a known inorganic filler (an inorganic filler other than the component (B)). These other components may be used alone or in combination of two or more. When the resin composition contains other components, they may be contained in an amount of 5% by mass or less relative to the total mass of the resin composition. From the viewpoint of low dust generation of the resulting molded product, it is preferable that the resin composition does not contain a fibrous filler.

The resin composition according to this embodiment has excellent fluidity and therefore good moldability. In one embodiment, the melt viscosity of the resin composition, measured at a temperature 10 to 40°C higher than the melting point of component (A) and at a shear rate of 1000/sec using a method in accordance with ISO 11443, is preferably 50 Pa·s or less, and more preferably 40 Pa·s or less.

[Method of producing resin composition]
The method for producing the resin composition according to the present embodiment is not particularly limited as long as it is a method that can uniformly mix the components (A) and (B), and if necessary the component (C) and other components, and a method for producing a resin composition known in the art can be appropriately selected. For example, there is a method in which the components are melt-kneaded and extruded using a melt-kneading device such as a single-screw or twin-screw extruder, and the resulting resin composition is then processed into a desired form such as powder, flakes, or pellets.

[Molding]
The molded article according to the present embodiment is obtained by molding the above-mentioned resin composition. The molded article according to the present embodiment is excellent in flowability, heat resistance and toughness because it contains the above-mentioned (A) wholly aromatic polyester. In addition, since the (A) component is combined with a specific amount of the (B) component, low dust generation can also be achieved.

As described above, the molded article obtained by molding the resin composition according to this embodiment has excellent toughness and can achieve low dust generation. In one embodiment, the bending strain (breaking point) of the molded article measured by a method conforming to ISO178 is preferably 5.0% or more, more preferably 5.5% or more, and even more preferably 6.0% or more.

In addition, the molded article according to this embodiment has good heat resistance because it contains a specific amount of the aforementioned component (A). In one embodiment, the deflection temperature under load of the molded article measured according to a method conforming to ISO 75-1, 2 is preferably 200°C or higher, and more preferably 210°C or higher.

<Method of manufacturing molded products>
The method for producing the molded article according to the present embodiment is not particularly limited, and a general molding method can be used, such as injection molding, extrusion molding, compression molding, blow molding, vacuum molding, foam molding, rotational molding, gas injection molding, inflation molding, etc.

[Application]
The resin composition according to the present embodiment has excellent fluidity. In addition, a molded product obtained from the resin composition has low dust generation, excellent toughness, and good heat resistance. Therefore, it can be suitably used for precision equipment applications, particularly as camera module parts. That is, one aspect of the resin composition according to the present embodiment is its use as a raw material for producing camera module parts.

<Camera module parts>
The molded product of the resin composition according to this embodiment can be used as a camera module part. That is, the resin composition according to this embodiment can be used to manufacture a camera module part. By using the resin composition according to this embodiment, a camera module part having excellent low dust generation and toughness, as well as good flowability and heat resistance, can be obtained. Hereinafter, an example of a camera module part obtained by molding the resin composition according to this embodiment will be described.

Figure 1 is a schematic cross-sectional view of a typical camera module. The camera module 1 in Figure 1 includes a substrate 10, an optical element 11, lead wiring 12, a holder 13, a barrel 14, a lens 15, and an IR filter 16.

The optical element 11 is disposed on the substrate 10, and the optical element 11 and the substrate 10 are electrically connected by lead wiring 12.

The holder 13 is disposed on the substrate 10 so as to cover the optical element 11. The top of the holder 13 is open, and a spiral groove is formed on the wall of this opening.

The barrel 14 is cylindrical, and the lens 15 is held inside the cylinder so that it is approximately horizontal. A helical protrusion is formed on the side wall of one end of the cylinder, and this helical protrusion is screwed into a helical groove formed on the wall of the opening of the holder 13, connecting the barrel 14 to the holder 13. An IR filter 16 is disposed at one end of the barrel 14 so as to close one end of the cylindrical barrel 14. In FIG. 1, the IR filter 16 and the lens 15 are disposed so as to be approximately parallel.

In the camera module 1 of FIG. 1, the distance between the lens 15 and the optical element 11 changes as the barrel 14 rotates. The focus of the camera can be adjusted by adjusting this distance. Specifically, the focus is adjusted by moving a spiral convex portion formed on the side wall of the end of the barrel 14 along a spiral groove portion formed on the wall surface of the opening of the holder 13. At this time, the spiral groove portion and the spiral convex portion rub against each other at the contact surface, and may wear and generate dust. The molded product obtained from the resin composition according to this embodiment has low dust generation and excellent toughness, so that dust generation due to collision or wear between parts can be suppressed. Therefore, the resin composition according to this embodiment can be suitably used as a raw material for manufacturing camera module parts such as the holder 13 and barrel 14 described above. In this disclosure, the "dust generation" can be evaluated by the number of dust particles generated when the molded product is washed with an ultrasonic cleaner.

The present invention will be explained in more detail below with reference to examples, but the interpretation of the present invention is not limited to these examples.

[Example 1]
(A) Preparation of fully aromatic polyester)
A polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a pressure reduction/outlet line was charged with the following raw material monomers, fatty acid metal salt catalyst, and fatty acid anhydride, and nitrogen replacement was started.
(I) 1,4-phenylenedicarboxylic acid (TA) 0.5 mol (25 mol%)
(II) 2,6-naphthalenedicarboxylic acid (NDA) 0.5 mol (25 mol%)
(III) 4,4'-dihydroxybiphenyl (BP) 0.5 mol (25 mol%)
(IV) 1,4-dihydroxybenzene (HQ) 0.5 mol (25 mol%)
Potassium acetate catalyst 150 ppm
Acetic anhydride 2.08 moles (1.04 equivalents based on the total amount of hydroxyl groups of BP and HQ)

After the raw materials were charged, the temperature of the reaction system was raised to 140°C and the reaction was carried out at 140°C for 3 hours (acylation step). The temperature was then raised further to 360°C over 4.5 hours, and the pressure was then reduced to 10 Torr (i.e. 1330 Pa) over 15 minutes, and polycondensation was carried out while distilling off acetic acid, excess acetic anhydride, and other low boiling points (polycondensation reaction step). After the stirring torque reached a predetermined value, nitrogen was introduced to change the reduced pressure to normal pressure and then to pressurized, and the polymer was discharged from the bottom of the polymerization vessel. The strands were then pelletized to obtain pellets of (A) wholly aromatic polyester.

[Preparation of resin composition]
75% by mass of the (A) wholly aromatic polyester prepared above and 25% by mass of mica (manufactured by Yamaguchi Mica Co., Ltd., product name: AB-25S) as (B) non-fibrous filler were melt-kneaded at a cylinder temperature of 350°C using a twin-screw extruder (manufactured by The Japan Steel Works, Ltd., product name: TEX30α) to obtain pellets of the resin composition of Example 1. In addition, the melt viscosity, deflection temperature under load, bending distortion (breaking point), and dust generation rate of the resin composition were measured by the following methods. The results are shown in Table 1.

<Measurement of Melt Viscosity of Resin Composition>
The melt viscosity of the obtained resin composition was measured using a capillary rheometer (manufactured by Toyo Seiki Seisakusho, Ltd., product name: Capilograph) at the following cylinder temperature and shear rate of 1000/sec in accordance with ISO 11443. An orifice with an inner diameter of 1 mm and a length of 20 mm was used for the measurement.
Cylinder Temperature:
Example 1, Examples 5 to 8, Comparative Example 2: 350° C.
Examples 2 to 4, Comparative Example 1: 370° C.

<Measurement of deflection temperature under load>
The pellets of the obtained resin composition were injection molded under the following molding conditions to prepare bending test pieces of 80 mm x 10 mm x 4 mm. The deflection temperature under load of the obtained test pieces was measured in accordance with ISO 75-1 and 2. The bending stress was set to 1.8 MPa.
(Molding condition)
・Molding machine: Sumitomo Heavy Industries, Ltd., product name: SE100DU
・Cylinder temperature:
Example 1, Examples 5 to 8, Comparative Example 2: 350° C.
Examples 2 to 4, Comparative Example 1: 370° C.
Mold temperature: 80°C
Injection speed: 33 mm/sec
・Pressure holding: 50MPa

<Measurement of bending strain (breaking point)>
The resulting resin composition pellets were injection molded under the following molding conditions to prepare bending test pieces of 80 mm x 10 mm x 4 mm. The bending strain (breaking point) of the obtained test pieces was measured under the following test conditions in accordance with ISO178.
(Molding condition)
・Molding machine: Sumitomo Heavy Industries, Ltd., product name: SE100DU
・Cylinder temperature:
Example 1, Examples 5 to 8, Comparative Example 2: 350° C.
Examples 2 to 4, Comparative Example 1: 370° C.
Mold temperature: 90°C
Injection speed: 33 mm/sec
・Pressure holding: 50MPa
(Test condition)
Test speed: 2.0 mm/min
Distance between supports: 64 mm
Indenter radius: 5 mm
・Radius of support stand: 5mm
- Elastic modulus: secant method

<Number of dust particles generated>
The pellets of the obtained resin composition were injection molded under the following conditions to prepare a test piece of 12.5 mm x 120 mm x 0.8 mm. The test piece was immersed in an ultrasonic cleaner (output 300 W, frequency 45 kHz) and ultrasonically cleaned in water (80 mL) at room temperature for 3 minutes. Thereafter, the number of particles of 2 μm or more present in 10 mL of the water was measured using a particle counter (manufactured by RION Co., Ltd., product name: liquid-borne particle counter KL-11A (PARTICLE COUNTER)) and evaluated as the number of dust generation. The results are shown in Table 1.
(Molding condition)
・Molding machine: Sumitomo Heavy Industries, Ltd., product name: SE30DUZ
・Cylinder temperature:
Example 1, Examples 5 to 8, Comparative Example 2: 350° C.
Examples 2 to 4, Comparative Example 1: 370° C.
Mold temperature: 80°C
Injection speed: 100 mm/sec

[Examples 2 to 8, Comparative Examples 3 to 6]
Pellets of (A) wholly aromatic polyester were prepared in the same manner as in Example 1, except that the raw material monomers and their blending amounts were as shown in Table 1. Next, pellets of a resin composition were obtained in the same manner as in Example 1, except that the blending amounts of components (A) to (B) (blend amounts of components (A) to (C) in Example 7) were as shown in Table 1. The melt viscosity, deflection temperature under load, bending distortion (breaking point), and dust generation rate of the obtained pellets of the resin composition were measured in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
A polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a pressure reduction/outlet line was charged with the following raw material monomers, fatty acid metal salt catalyst, and fatty acid anhydride, and nitrogen replacement was started.
(I) 1,4-phenylenedicarboxylic acid (TA) 0.46 mol (25 mol%)
(III) 4,4'-dihydroxybiphenyl (BP) 0.46 mol (25 mol%)
4-Hydroxybenzoic acid (HBA) 0.037 mol (2 mol%)
6-Hydroxy-2-naphthoic acid (HNA) 0.883 mol (48 mol%)
Potassium acetate catalyst 150 ppm
Acetic anhydride 1.914 moles (1.04 equivalents based on the total amount of hydroxyl groups of BP, HBA and HNA)

After the raw materials were charged, the temperature of the reaction system was raised to 140°C and reacted at 140°C for 3 hours (acylation step). The temperature was then raised to 360°C over 4.5 hours, and the pressure was reduced to 10 Torr (i.e. 1330 Pa) over 15 minutes, and polycondensation was carried out while distilling out acetic acid, excess acetic anhydride, and other low boiling points (polycondensation reaction step). After the stirring torque reached a predetermined value, nitrogen was introduced to change the reduced pressure state to normal pressure and then to a pressurized state, and the polymer was discharged from the bottom of the polymerization vessel. The strands were then pelletized to obtain pellets of fully aromatic polyester. Next, pellets of a resin composition were prepared using the fully aromatic polyester prepared above with the composition shown in Table 1. The resin composition was prepared in the same manner as in Example 1. The melt viscosity, deflection temperature under load, bending distortion (breaking point), and dust generation number were measured for the obtained pellets of the resin composition in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 2]
(I) 1,4-phenylenedicarboxylic acid (TA) 0.28 mol (14 mol%)
(VI) 1,3-phenylenedicarboxylic acid (IA) 0.12 mol (6 mol%)
(III) 4,4'-dihydroxybiphenyl (BP) 0.4 mol (20 mol%)
4-Hydroxybenzoic acid (HBA) 1.2 moles (60 mole%)
Potassium acetate catalyst 150 ppm
Acetic anhydride: 2.08 moles (1.04 equivalents based on the total amount of hydroxyl groups in BP and HBA)

After the raw materials were charged, the temperature of the reaction system was raised to 140°C and reacted at 140°C for 3 hours (acylation step). The temperature was then raised to 360°C over 4.5 hours, and the pressure was reduced to 10 Torr (i.e. 1330 Pa) over 15 minutes, and polycondensation was carried out while distilling out acetic acid, excess acetic anhydride, and other low boiling points (polycondensation reaction step). After the stirring torque reached a predetermined value, nitrogen was introduced to change the reduced pressure state to normal pressure and then to a pressurized state, and the polymer was discharged from the bottom of the polymerization vessel. The strands were then pelletized to obtain pellets of fully aromatic polyester. Next, pellets of a resin composition were prepared using the fully aromatic polyester prepared above with the composition shown in Table 1. The resin composition was prepared in the same manner as in Example 1. The melt viscosity, deflection temperature under load, bending distortion (breaking point), and dust generation number were measured for the obtained pellets of the resin composition in the same manner as in Example 1. The results are shown in Table 1.

The materials used in this example are as follows:
(B) Non-fibrous filler Mica: manufactured by Yamaguchi Mica Co., Ltd., product name: AB-25S, median diameter: 25.0 μm.
Talc: manufactured by Matsumura Sangyo Co., Ltd., product name: Crown Talc PP, median diameter: 14.6 μm.
(C) Epoxy Group-Containing Polymer (C1) Ethylene-glycidyl methacrylate copolymer: manufactured by Sumitomo Chemical Co., Ltd., product name: Bondfast (registered trademark) 2C, glycidyl methacrylate content: 6 mass %.

As shown in Table 1, the molded articles obtained from the resin compositions of Examples 1 to 8 satisfying the constitution of the present invention had low melt viscosity and excellent fluidity. In addition, the deflection temperature under load was high and the heat resistance was excellent. Furthermore, the bending strain (breaking point) was 6.0% or more and the toughness was excellent. Furthermore, the number of dust generation was small. On the other hand, the molded articles obtained from the resin compositions of Comparative Examples 1 and 2 containing the wholly aromatic polyester not satisfying the constitution of the present invention had good fluidity and heat resistance, but low toughness and a large number of dust generation. In Comparative Examples 3 to 6, solidification occurred during polymerization of the wholly aromatic polyester, and no polymer was obtained. From the above results, it was confirmed that molded articles having low dust generation and excellent toughness, as well as good fluidity and heat resistance, can be obtained from the resin compositions satisfying the constitution of the present invention. Such molded articles can be suitably used as precision instruments, especially camera module parts.

REFERENCE SIGNS LIST 1 camera module 10 substrate 11 optical element 12 lead wiring 13 holder 14 barrel 15 lens 16 IR filter

Claims (11)

A resin composition comprising:
The resin composition contains (A) a wholly aromatic polyester and (B) a non-fibrous filler,
The wholly aromatic polyester (A) contains, as essential components, the following structural units (I), (II), (III), and (IV):
Including,
Ar ₁ in the structural unit (III) represents 2,6-naphthalene or 4,4′-biphenylene;
The content of the structural unit (I) is 15 to 30 mol % based on all structural units,
The content of the structural unit (II) is 20 to 35 mol % based on all structural units,
The content of the structural unit (III) is 15 to 30 mol % based on all structural units,
The content of the structural unit (IV) is 20 to 35 mol % based on all structural units,
(B) the non-fibrous filler comprises at least one filler selected from the group consisting of plate-like fillers and granular fillers having a median diameter of 50 μm or less;
(A) the content of the wholly aromatic polyester is 60 to 90% by mass based on the total mass of the resin composition,
(B) A resin composition having a non-fibrous filler content of 10 to 40 mass% based on the total mass of the resin composition. The resin composition according to claim 1, in which the total content of the structural units (I) to (IV) is 90 to 100 mol % based on the total structural units of the wholly aromatic polyester (A). The wholly aromatic polyester (A) further comprises the following structural unit (V):
Including,
The resin composition according to claim 1 or 2, wherein the total content of the structural units (I), (II) and (V) is 47.5 to 52.5 mol% based on all structural units. The wholly aromatic polyester (A) further comprises the following structural unit (VI):
Including,
The resin composition according to claim 1 or 2, wherein the total content of the structural units (III), (IV) and (VI) is 47.5 to 52.5 mol% based on all structural units. The resin composition according to claim 1 or 2, wherein (B) the non-fibrous filler comprises at least one selected from the group consisting of talc, mica, silica, and barium sulfate. The resin composition further comprises (C) an epoxy group-containing polymer,
(A) the content of the wholly aromatic polyester is 60 to 87.5% by mass based on the total mass of the resin composition,
(B) the content of the non-fibrous filler is 10 to 37.5% by mass based on the total mass of the resin composition;
The resin composition according to claim 1 or 2, wherein the content of the epoxy group-containing polymer (C) is 1 to 7 mass% based on the total mass of the resin composition. The resin composition according to claim 1 or 2, which is for use in camera module parts. Use of the resin composition according to claim 1 or 2 for manufacturing a camera module part. A molded article comprising the resin composition according to claim 1 or 2. The molded product according to claim 9, which is a camera module part. A camera module comprising the camera module component of claim 10.