JP2015048408A - Liquid crystalline polyester resin compositions and molded article thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystalline polyester resin compositions which high water vapor barrier property and increment of gas generation amount during a melt retention are inhibited and to provide a molded article containing the same.SOLUTION: There is provided a liquid crystalline polyester resin composition containing 100 pts.wt. of a liquid crystalline polyester (A) consisting of following structural units (I), (II), (III), (IV) and (V) and 10 to 200 pts.wt. of a glass fiber (B) and having a water vapor permeation degree of 0.05 g/m24hr atm or less at a temperature of 80°C and a relative humidity of 40% and 0.2 wt.% or less of increment of the amount of the generated gas during a melt retention at the melting point of the liquid crystalline polyester+10°C for 10 minutes from the amount of the generated gas before the melt retention.

Description

  The present invention relates to a liquid crystalline polyester resin composition. More specifically, the present invention relates to a liquid crystalline polyester resin composition containing liquid crystalline polyester and glass fiber, which has a low water vapor permeability and excellent moldability, and a molded article comprising the same.

  Liquid crystalline polyester is excellent in heat resistance, fluidity and dimensional stability due to its liquid crystal structure. For this reason, the demand is increasing mainly for small electric / electronic parts that require these characteristics. Further, attention has been paid to the above characteristics of the liquid crystalline polyester, and the use of the liquid crystalline polyester as a material for the container has been studied. By the way, when liquid crystalline polyester is used as a resin container for storing and storing foods, chemicals, fuels, etc., deterioration of contents due to the entry and exit of water vapor is a problem. In addition, when used as a resin case for precision equipment, condensation inside the container due to moisture and malfunction of the equipment are problematic. In order to suppress these problems, the resin container is required to have a high water vapor barrier property. Here, since liquid crystalline polyester has excellent water vapor barrier properties derived from its unique molecular structure, studies for various containers have been proposed, and the content of repeating units containing 2,6-naphthylene groups is proposed. Has been proposed a fuel tank excellent in weather resistance composed of a liquid crystalline polyester having an amount of 40 mol% or more based on the total amount of all repeating units (see, for example, Patent Document 1). In addition, a sheet and a container that are made of liquid crystalline polyester and an epoxy group-containing thermoplastic resin and have improved workability have been proposed (for example, see Patent Document 2). In addition, a tank made of liquid crystalline polyester amide that has excellent strength at the time of water absorption and excellent gas (hydrogen, oxygen, carbon dioxide) barrier properties has been proposed. (For example, refer to Patent Document 3).

JP 2011-38029 A JP-A-9-249798 JP 2005-60455 A

  However, in such prior art, there is not enough mention about the decrease in adhesion at the interface between the resin and the filler due to the generated gas due to melting and retention of the resin during molding, and the generation of voids inside the molded product. There existed a subject that water vapor | steam barrier property fell. In addition, due to an increase in the amount of gas generated due to melting and staying of the resin during molding, there is a variation in the cushion amount during molding, and the quality of the molded product is not stable during molding into a container or the like. Further, in the prior art, it is used as a film application in a non-strengthening system which does not substantially use a filler, and has a problem that it is difficult to use in various forms of containers. Even in this case, there was a problem that the adhesiveness between the resin and the filler was lowered and the water vapor barrier property was lowered due to thermal deterioration accompanying shearing heat generation during compounding.

  The present invention is excellent in water vapor barrier properties, and by suppressing an increase in the amount of gas generated at the time of melting and staying, variation in cushion amount during molding can be suppressed, and therefore a liquid crystalline polyester resin composition having excellent moldability. The object is to provide a product and a molded product comprising the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have blended glass fibers with a liquid crystalline polyester composed of a specific structural unit, and have a specific water vapor permeability and a gas generation amount during melt residence. As a result, the present inventors have found that the liquid crystalline polyester resin composition is excellent in molding stability and suitable for use in containers.

That is, the present invention has been made to solve the above-described problems, and embodiments of the present invention can include at least a part of the following configurations.
(1) 10 to 200 parts by weight of glass fiber (B) with respect to 100 parts by weight of liquid crystalline polyester (A) comprising the following structural units (I), (II), (III), (IV) and (V) A liquid crystalline polyester resin composition containing a water vapor permeability of not more than 0.05 g / m ² · 24 hr · atm at a temperature of 80 ° C. and a relative humidity of 40%, and a melting point of the liquid crystalline polyester + 10 ° C. for 10 minutes. A liquid crystalline polyester resin composition characterized in that the amount of gas generated at the time of melt residence is 0.2% by weight or less from the amount of gas generated before the melt residence.

(2) In the liquid crystalline polyester (A), the structural unit (I) is 65 to 80 mol% with respect to the total of the structural units (I), (II) and (III), and the structural unit (II) is a structural 55 to 85 mol% with respect to the sum of units (II) and (III), structural unit (IV) is 50 to 95 mol% with respect to the sum of structural units (IV) and (V), The liquid crystalline polyester resin composition according to (1), wherein the sum of the units (II) and (III) and the sum of (IV) and (V) are substantially equimolar.
(3) The amount of generated gas of the liquid crystalline polyester (A) (melting point of the liquid crystalline polyester + weight reduction when held at 10 ° C. for 30 minutes) is 0.2% by weight or less (1) or The liquid crystalline polyester resin composition according to (2).
(4) A molded product obtained by molding the liquid crystalline polyester resin composition according to any one of (1) to (3).

  According to the present invention, a liquid crystalline polyester resin composition having high water vapor barrier properties and molding stability can be obtained. In addition, a molded article made of the liquid crystalline polyester resin composition of the present invention is excellent in water vapor barrier properties and molding stability, and is therefore suitable for provision to container applications and the like, and particularly, excellent molding stability is required. It can be used for containers for foods, chemicals, fuels, etc. and cases for precision equipment such as electrical and electronic equipment.

  Hereinafter, the present invention will be described in detail.

[Liquid crystal polyester]
The liquid crystalline polyester (A) in the embodiment of the present invention is a polyester called a thermotropic liquid crystal polymer that exhibits optical anisotropy when melted, and has the following structural units (I), (II), (III), (IV ) And (V).

  The structural unit (I) was generated from p-hydroxybenzoic acid, the structural unit (II) was generated from 4,4′-dihydroxybiphenyl, and the structural unit (III) was generated from hydroquinone. The structural unit, the structural unit (IV) represents a structural unit produced from terephthalic acid, and the structural unit (V) represents a structural unit produced from isophthalic acid.

  Since the liquid crystalline polyester of the present invention is composed of the above structural units, the amount of gas generated is reduced, the adhesion at the interface between the liquid crystalline polyester and the glass fiber is reduced when the glass fiber is blended, and the water vapor associated therewith. A decrease in barrier properties can be suppressed. Furthermore, variations in the cushion amount during molding can be suppressed, and the moldability is excellent.

  The content of the structural unit (I) is preferably 65 mol% or more, more preferably 68 mol% or more with respect to the total content of the structural units (I), (II) and (III). On the other hand, the content of the structural unit (I) is preferably 80 mol% or less, and more preferably 78 mol% or less with respect to the total content of the structural units (I), (II) and (III).

  Moreover, 55 mol% or more is preferable with respect to the sum total of content of structural unit (II) and (III), and, as for content of structural unit (II), 58 mol% or more is more preferable. On the other hand, the content of the structural unit (II) is preferably 85 mol% or less, more preferably 78 mol% or less, and even more preferably 73 mol% or less with respect to the total content of the structural units (II) and (III). preferable.

  Further, the content of the structural unit (IV) is preferably 50 mol% or more, more preferably 55 mol% or more, further preferably 60 mol% or more with respect to the total content of the structural units (IV) and (V). . On the other hand, the content of the structural unit (IV) is preferably 95 mol% or less, more preferably 90 mol% or less, still more preferably 85 mol% or less, with respect to the total content of the structural units (IV) and (V). .

  Further, the sum of the structural units (II) and (III) and the sum of (IV) and (V) are substantially equimolar. Here, “substantially equimolar” means that the structural unit constituting the polymer main chain excluding the terminal is equimolar. For this reason, the aspect which does not necessarily become equimolar when it includes even the structural unit which comprises the terminal can satisfy the requirement of “substantially equimolar”.

In the embodiment of the present invention, a method for calculating the content of each structural unit is shown below. First, the liquid crystalline polyester is weighed into an NMR (nuclear magnetic resonance) test tube and dissolved in a solvent in which the liquid crystalline polyester is soluble (for example, a pentafluorophenol / heavy tetrachloroethane-d ₂ mixed solvent). Next, about a solution, < ¹ > H-NMR spectrum measurement can be performed and it can calculate from the peak area ratio derived from each structural unit.

  By making content of said structural unit (I)-(V) into the said range, since liquid crystalline polyester excellent in heat resistance, mechanical characteristics, and low gas property is obtained easily, it is preferable. A liquid crystalline polyester resin composition comprising the same is preferable because it has excellent water vapor barrier properties and excellent molding stability.

  The amount of gas generated by the liquid crystalline polyester in the present invention is a value obtained as a weight reduction amount when held for 30 minutes at the melting point of the liquid crystalline polyester + 10 ° C. in a thermogravimetric analyzer. Specifically, the weight of the liquid crystalline polyester before and after being held at high temperature is measured, and the weight reduction amount is defined as the amount of generated gas. The amount of generated gas can be measured using, for example, TGA-7 (manufactured by PerkinElmer).

  The amount of generated gas of the liquid crystalline polyester (A) in the embodiment of the present invention is preferably 0.2% by weight or less. More preferably, it is 0.18 weight% or less. More preferably, it is 0.15 weight% or less. It is preferable that the amount of gas generated by the liquid crystalline polyester is in the above range since the adhesiveness at the interface between the liquid crystalline polyester and the glass fiber is excellent and the water vapor transmission rate can be reduced when blended with the glass fiber.

  The melting point (Tm) of the liquid crystalline polyester (A) in the embodiment of the present invention is preferably 220 ° C. or higher, more preferably 270 ° C. or higher, and further preferably 300 ° C. or higher from the viewpoint of heat resistance. On the other hand, from the viewpoint of workability, the melting point (Tm) of the liquid crystalline polyester is preferably 350 ° C. or less, more preferably 345 ° C. or less, and further preferably 340 ° C. or less.

The melting point (Tm) is measured by differential scanning calorimetry. Specifically, first, an endothermic peak temperature (Tm ₁ ) is observed by heating the polymer that has been polymerized from room temperature to a temperature rising condition of 20 ° C./min. After observation of an endothermic peak temperature (Tm _1), holding the polymer for 5 minutes at a temperature of the endothermic peak temperature _(Tm 1) + 20 ℃. Thereafter, the polymer is cooled to room temperature under a temperature drop condition of 20 ° C./min. Then, the endothermic peak temperature (Tm ₂ ) is observed by heating the polymer under a temperature rising condition of 20 ° C./min. The melting point (Tm) refers to the endothermic peak temperature (Tm ₂ ).

  The number average molecular weight of the liquid crystalline polyester (A) in the embodiment of the present invention is preferably 3,000 or more, and more preferably 8,000 or more from the viewpoint of mechanical strength. On the other hand, from the viewpoint of fluidity, the number average molecular weight of the liquid crystalline polyester is preferably 50,000 or less, more preferably 30,000 or less, and even more preferably 20,000 or less.

  The number average molecular weight can be measured by GPC (gel permeation chromatograph) / LALLS method. In this method, a solvent in which the liquid crystalline polyester is soluble is used as an eluent. Examples of the solvent in which the liquid crystalline polyester is soluble include halogenated phenols and a mixed solvent of a halogenated phenol and a general organic solvent. Preferable are pentafluorophenol and a mixed solvent of pentafluorophenol and chloroform. Among them, a pentafluorophenol / chloroform mixed solvent is preferable from the viewpoint of handleability.

  GPC measurement includes, for example, a Waters GPC apparatus, a Waters differential refractive index detector RI2410, and Showa Denko's columns Shodex K-806M (two) and K-802 (one). Use to do. As an eluent, pentafluorophenol / chloroform (35/65 w / w%) is used. GPC measurement can be performed under the conditions of a measurement temperature of 23 ° C., a flow rate of 0.8 mL / min, and a sample injection amount of 200 μL (concentration: 0.1%). The LALLS measurement can be performed, for example, using a low angle laser light scattering photometer KMX-6 manufactured by Chromatix, under the conditions of a detector wavelength of 633 nm (He—Ne) and a detector temperature of 23 ° C.

  From the viewpoint of mechanical strength, the melt viscosity of the liquid crystalline polyester (A) in the embodiment of the present invention is preferably 1 Pa · s or more, more preferably 10 Pa · s or more, and further preferably 20 Pa · s or more. On the other hand, from the viewpoint of fluidity, the melt viscosity of the liquid crystalline polyester is preferably 200 Pa · s or less, more preferably 100 Pa · s or less, and even more preferably 50 Pa · s or less.

  The melt viscosity is a value measured by a Koka flow tester at a melting point (Tm) of the liquid crystalline polyester + 10 ° C. and under a shear rate of 1,000 / second.

There is no restriction | limiting in particular in the manufacturing method of liquid crystalline polyester (A) in embodiment of this invention, It can manufacture according to the well-known polyester polycondensation method. Examples of known polyester polycondensation methods include the following production methods.
(1) A method for producing a liquid crystalline polyester from p-acetoxybenzoic acid and 4,4′-diacetoxybiphenyl, diacetoxybenzene, terephthalic acid, and isophthalic acid by a deacetic acid polycondensation reaction.
(2) Liquid crystallinity by reacting p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl and hydroquinone with terephthalic acid and isophthalic acid with acetic anhydride to acetylate the phenolic hydroxyl group, followed by deacetic acid polycondensation A method for producing polyester.
(3) A method for producing a liquid crystalline polyester from phenyl p-hydroxybenzoate and 4,4′-dihydroxybiphenyl, hydroquinone, diphenyl terephthalate and diphenyl isophthalate by a dephenol polycondensation reaction.
(4) A predetermined amount of diphenyl carbonate is reacted with p-hydroxybenzoic acid and aromatic dicarboxylic acid such as terephthalic acid and isophthalic acid to form phenyl esters, respectively, and then aromatics such as 4,4′-dihydroxybiphenyl and hydroquinone. A method for producing a liquid crystalline polyester by adding a group dihydroxy compound and dephenol polycondensation reaction.

  Among them, (2) p-hydroxybenzoic acid and 4,4′-dihydroxybiphenyl, hydroquinone, terephthalic acid, and isophthalic acid are reacted with acetic anhydride to acetylate the phenolic hydroxyl group, and then liquid crystal is obtained by deacetic acid polycondensation reaction. A method for producing a conductive polyester is preferably used because it is industrially excellent in controlling the terminal structure of the liquid crystalline polyester and controlling the degree of polymerization.

  In the said manufacturing method, the usage-amount of acetic anhydride is more than 1.00 molar equivalent of the sum total of the phenolic hydroxyl group of p-hydroxybenzoic acid, 4,4'- dihydroxybiphenyl, and hydroquinone from a viewpoint of advancing a polymerization reaction rapidly. Preferably, it is 1.03 molar equivalent or more, and more preferably 1.05 molar equivalent or more. On the other hand, from the viewpoint of controlling the terminal structure of the liquid crystalline polyester, the amount of acetic anhydride used is preferably 1.15 molar equivalents or less of the total of the phenolic hydroxyl groups of p-hydroxybenzoic acid, 4,4′-dihydroxybiphenyl and hydroquinone. 1.12 molar equivalents or less is more preferable. Furthermore, by making the usage-amount of acetic anhydride into the said range, the acetylation rate of hydroquinone with a small acetylation reaction rate can be controlled, and the terminal structure of liquid crystalline polyester can be controlled easily. Thereby, a liquid crystalline polyester with less gas generation can be obtained, and a liquid crystalline polyester resin composition comprising the same has a low water vapor permeability and excellent molding stability.

  The following method is preferable as the method for producing the liquid crystalline polyester by the deacetic acid polycondensation reaction in the embodiment of the present invention. Specifically, it is a melt polymerization method in which the polycondensation reaction is completed by reacting under reduced pressure in a state where the liquid crystalline polyester is melted. The melt polymerization method is an advantageous method for producing a uniform polymer, and is preferable because a polymer with less gas generation can be obtained.

  Specifically, the method for producing the liquid crystalline polyester by a deacetic acid polycondensation reaction includes the following methods. A predetermined amount of p-hydroxybenzoic acid and 4,4'-dihydroxybiphenyl, hydroquinone, terephthalic acid, isophthalic acid and acetic anhydride are charged into a reaction vessel and heated with stirring in a nitrogen gas atmosphere to acetylate the hydroxyl group. Let The reaction vessel includes a stirring blade and a distillation pipe, and a discharge port in the lower part. Thereafter, the mixture is heated up to the melting temperature of the liquid crystalline polyester and then subjected to polycondensation by reducing the pressure to complete the reaction.

  The temperature for acetylation is preferably 130 ° C. or higher, more preferably 135 ° C. or higher, from the viewpoint of promoting the progress of the reaction. On the other hand, from the viewpoint of suppressing the excessive progress of the reaction, the temperature for acetylation is preferably 300 ° C. or lower, more preferably 200 ° C. or lower. The acetylation reaction time is preferably 1 hour or longer from the viewpoint of increasing the reaction rate. On the other hand, from the viewpoint of productivity, the acetylation reaction time is preferably 6 hours or less, and more preferably 4 hours or less. The polycondensation temperature is a melting temperature of the liquid crystalline polyester, for example, in the range of 250 to 365 ° C., and preferably a melting point of the liquid crystalline polyester + 10 ° C. or higher.

  In the present invention, it is preferable to control the sequence of the oligomer generated at the initial stage of the reaction by controlling the reactivity of the monomer in the deacetic acid polycondensation. By controlling the sequence of the oligomer, the sequence of the obtained liquid crystalline polyester can be controlled more easily. Thereby, the water vapor permeability of the molded product in a high-temperature and high-humidity environment can be further reduced.

  As a method for controlling the sequence of the oligomer generated in the initial stage of the deacetic acid polycondensation reaction within a suitable range, for example, the temperature rise time from 200 ° C. to 270 ° C. in the deacetic acid polycondensation step is 75 minutes to 95 minutes. And a method of adding an aromatic or aliphatic amine containing two or more nitrogen atoms at least before the start of the deacetic acid polycondensation reaction. By controlling the temperature rising time from 200 ° C. to 270 ° C. within the above range, the reaction rate of highly reactive p-hydroxybenzoic acid is controlled, and a chain of p-hydroxybenzoic acid is generated appropriately, and molding is performed. It is possible to further reduce the water vapor permeability of the product in a high temperature and high humidity environment. Moreover, the chain length of p-hydroxybenzoic acid can also be controlled by adding an aromatic or aliphatic amine containing two or more nitrogen atoms, and the water vapor permeability of the molded product in a high-temperature and high-humidity environment can be controlled. It can be further reduced.

  The pressure for polycondensation is preferably 0.1 mmHg (13.3 Pa) or more from the viewpoint of productivity. On the other hand, from the viewpoint of promoting the polycondensation reaction, the pressure during polycondensation is preferably 20 mmHg (2660 Pa) or less, more preferably 10 mmHg (1330 Pa) or less, and even more preferably 5 mmHg (665 Pa) or less.

  In addition, acetylation and polycondensation may be performed continuously in the same reaction vessel, or acetylation and polycondensation may be performed in different reaction vessels.

  As a method for taking out the obtained polymer from the reaction vessel after completion of the polymerization, the following methods may be mentioned. In this method, the inside of the reaction vessel is pressurized at a temperature at which the polymer melts, the polymer is discharged from a discharge port provided in the reaction vessel, and the discharged polymer is cooled in cooling water. The pressurization in the reaction vessel may be, for example, 0.02 to 0.5 MPa. The discharge port may be provided at the lower part of the reaction vessel. The polymer may be discharged in a strand form from the discharge port. Resin pellets can be obtained by cutting the polymer cooled in the cooling liquid into pellets.

  As a method for producing the liquid crystalline polyester in the embodiment of the present invention, the polycondensation reaction can be completed by a solid phase polymerization method. Examples of the treatment by the solid phase polymerization method include the following methods. The polymer or oligomer of the liquid crystalline polyester in the embodiment of the present invention is pulverized by a pulverizer. The pulverized polymer or oligomer is heated under a nitrogen stream or under reduced pressure, and polycondensed to a desired degree of polymerization to complete the reaction. The said heating is good also as performing it for 1 to 50 hours in the range of melting | fusing point-5 degreeC-melting point-50 degreeC (for example, 200-300 degreeC) of liquid crystalline polyester.

  Although the polycondensation reaction of the liquid crystalline polyester as an embodiment of the present invention proceeds even without a catalyst, a metal compound such as stannous acetate, tetrabutyl titanate, potassium acetate and sodium acetate, antimony trioxide, and magnesium metal is used as a catalyst. It can also be used.

[Glass fiber]
If the glass fiber (B) in embodiment of this invention is generally used for reinforcement | strengthening of resin, there will be no limitation in particular. The glass fiber can be selected from long fiber type and short fiber type chopped strands, milled fibers, and the like. Two or more kinds of glass fibers may be used in combination.

  The glass fiber used in the embodiment of the present invention is preferably weakly alkaline in terms of mechanical strength. In particular, glass fibers having a silicon oxide content of 50 to 80% by weight are preferably used, and more preferably glass fibers having a silicon oxide content of 65 to 77% by weight. The glass fiber is preferably treated with an epoxy-based, urethane-based, acrylic-based coating or sizing agent, and epoxy-based is particularly preferable.

  The glass fiber (B) is preferably treated with a coupling agent such as silane or titanate or other surface treatment agent, and an epoxysilane or aminosilane coupling agent is particularly preferred. The glass fiber may be coated or bundled with a thermoplastic resin such as ethylene / vinyl acetate copolymer or a thermosetting resin such as epoxy resin. It is preferable that the glass fiber is treated with the coupling agent or the like because the adhesion between the liquid crystalline polyester and the glass fiber is excellent and the water vapor permeability can be improved.

  The glass fiber (B) content is 10 to 200 parts by weight with respect to 100 parts by weight of the liquid crystalline polyester (A). By setting the glass fiber content to 10 parts by weight or more, heat resistance and mechanical strength can be further improved. The content of the glass fiber is more preferably 20 parts by weight or more, and further preferably 30 parts by weight or more. Moreover, fluidity | liquidity can be improved by making content of glass fiber into 200 weight part or less. The content of glass fiber is more preferably 150 parts by weight or less, and still more preferably 100 parts by weight or less.

  When the content of the glass fiber (B) is 10 parts by weight or less with respect to 100 parts by weight of the liquid crystalline polyester (A), or when the glass fiber is not contained, water vapor is transmitted in the liquid crystalline polyester resin composition. In addition, since the glass fiber component with a small amount of gas generation is reduced, the water vapor barrier property is lowered, and the moldability is deteriorated due to an increase in the cushion variation during molding due to an increase in the amount of gas generation. Furthermore, since the reinforcing effect is reduced due to the low glass fiber content, the strength of the molded product may not be sufficiently obtained. On the other hand, if the glass fiber content is 200 parts by weight or more with respect to 100 parts by weight of the liquid crystalline polyester, the shear heat generation at the time of the liquid crystalline polyester resin composition compound increases, and the thermal deterioration of the resin is promoted. The amount of generated gas increases, and the water vapor barrier property and cushion variation during molding deteriorate.

  The liquid crystalline polyester resin composition according to the embodiment of the present invention is not limited to the glass fiber (B) as a filler, as long as the effects of the present invention are not impaired, and further, fibrous, plate-like, powdery, granular, etc. The filler may be blended. Specifically, polyacrylonitrile (PAN) and pitch-based carbon fibers, stainless steel fibers, metal fibers such as aluminum fibers and brass fibers, organic fibers such as aromatic polyamide fibers, gypsum fibers, ceramic fibers, asbestos fibers, zirconia Fibrous or whisker-like filling such as fiber, alumina fiber, silica fiber, titanium oxide fiber, silicon carbide fiber, rock wool, potassium titanate whisker, barium titanate whisker, aluminum borate whisker, silicon nitride whisker, acicular titanium oxide And powder, granular or plate-like fillers such as mica, talc, kaolin, silica, glass beads, glass flakes, clay, molybdenum disulfide, wollastonite, titanium oxide, zinc oxide, calcium polyphosphate and graphite It is done. The surface of the filler may be treated with a known coupling agent (such as a silane coupling agent or a titanate coupling agent) or other surface treatment agent. Two or more fillers may be used in combination.

The liquid crystalline polyester resin composition according to the embodiment of the present invention has a water vapor permeability (hereinafter sometimes simply referred to as water vapor permeability) at a temperature of 80 ° C. and a relative humidity of 40% of 0.05 g / m ² · 24 hr · atm or less. It is characterized by being. Containers for transporting and storing food, etc., and electrical / electronic components may be exposed to high temperatures depending on the use conditions. Therefore, typical characteristics under the assumed high temperature environment are water vapor permeability at a temperature of 80 ° C. Pay attention. In addition, at a temperature of 80 ° C., attention was paid to the water vapor transmission rate at a relative humidity of 40% as a condition that clearly shows the difference in water vapor transmission rate. The water vapor permeability is preferably 0.04 g / m ² · 24 hr · atm or less, more preferably 0.03 g / m ² · 24 hr · atm or less. The lower limit of water vapor permeability is 0 g / m ² · 24 hr · atm.

If the water vapor transmission rate is greater than 0.05g / m ² · 24hr · atm, the contents of the container such as food, chemicals, and fuel may deteriorate due to the entry and exit of water vapor into the container, and the equipment may be erroneous due to internal condensation in the precision instrument case. Operation may occur.

  As a means for bringing the water vapor permeability and the amount of generated gas of the liquid crystalline polyester resin composition in the embodiment of the present invention into the aforementioned ranges, a method using a liquid crystalline polyester comprising a structural unit within the scope of the present invention described above, , Liquid crystalline polyester and glass fiber, or other fillers may be mixed by a preferable mixing method described later.

  In the liquid crystalline polyester resin composition in the embodiment of the present invention, the water vapor of the liquid crystalline polyester resin composition is compared with that of the non-reinforced liquid crystalline polyester by blending glass fibers that do not transmit water vapor compared with the liquid crystalline polyester. The permeability can be reduced. Moreover, by mix | blending glass fiber, the strong molecular orientation of liquid crystalline polyester is moderated moderately, the space | gap between the molecular chains of liquid crystalline polyester reduces, and water vapor permeability can be reduced.

  The water vapor transmission rate in the present invention refers to a value measured under conditions of a temperature of 80 ° C. and a relative humidity of 40% in accordance with JIS K7129 (Appendix C, 2008). Such water vapor permeability can be measured using, for example, GTR-30XATK (manufactured by GTR Tech). Note that an injection-molded square plate having a length of 70 mm × 70 mm width × 1 mm (fin gate) is used as a measurement sample.

  In the liquid crystalline polyester resin composition according to the embodiment of the present invention, the amount of gas generated at the time of melting and residence for 10 minutes at the melting point of the liquid crystalline polyester (A) + 10 ° C. is 0.2% by weight or less. It is characterized by being. Due to the small increase in the amount of gas generated before and after the melt residence, when the liquid crystalline polyester resin composition melts and stays inside the cylinder during molding, air is trapped inside the molded product by the generated gas and the water vapor permeability is thereby Can be suppressed. In addition, since the amount of generated gas is small, variation in the cushion amount during molding is reduced, the thermal history of the liquid crystalline polyester resin composition is constant, and a product with uniform quality is obtained, resulting in improved molding stability. Excellent. The increase in the amount of gas generated before and after the melt residence is preferably 0.17% by weight or less. More preferably, it is 0.15 weight% or less.

  When the amount of gas generated before and after the melt residence is larger than the above range, the adhesion at the interface between the liquid crystalline polyester and the glass fiber is lowered, and the water vapor permeability is increased. In addition, there is a decrease in molding stability due to the occurrence of air entrainment in the molded product and variations in the cushion amount during molding.

  In the liquid crystalline polyester resin composition according to the embodiment of the present invention, the amount of generated gas is smaller than that of the liquid crystalline polyester, so that the liquid crystalline polyester resin composition has a smaller amount of generated gas than the non-reinforced liquid crystalline polyester. It is possible to suppress an increase in the amount of gas generated before and after melt retention during molding, thereby suppressing variations in cushion amount during molding and improving moldability.

  The liquid crystalline polyester resin composition according to the embodiment of the present invention further includes an antioxidant, a heat stabilizer (for example, hindered phenol, hydroquinone, phosphites, and substituted products thereof as long as the effects of the present invention are not impaired. ), Ultraviolet absorbers (eg, resorcinol, salicylate), anti-coloring agents such as phosphites and hypophosphites, lubricants and mold release agents (montanic acid and its metal salts, esters thereof, half esters thereof, Stearyl alcohol, stearamide and polyethylene wax), colorants including dyes or pigments, carbon black, crystal nucleating agents, plasticizers, flame retardants (bromine flame retardants, phosphorus flame retardants, red phosphorus, Silicone flame retardants), flame retardant aids, and conventional additives selected from antistatic agents Can. Alternatively, a polymer other than the liquid crystalline polyester can be blended to further impart predetermined characteristics.

  The method for blending glass fiber, other fillers, additives, and the like with the liquid crystalline polyester in the embodiment of the present invention is not particularly limited, and is a dry blend or solution blending method, polymerization of the liquid crystalline polyester resin. Addition and melt kneading can be used, and melt kneading is particularly preferred. A known method can be used for melt kneading. For example, using a Banbury mixer, rubber roll machine, kneader, single-screw or twin-screw extruder, the liquid crystalline polyester resin composition is melt-kneaded from the liquid crystal starting temperature of the liquid crystalline polyester resin composition to the melting point + 50 ° C. or lower to obtain a liquid crystalline polyester resin composition. be able to.

  The liquid crystal start temperature is a temperature at which flow starts under the condition of a shear rate of 1000 / second. The liquid crystal start temperature is measured by, for example, a shear rate heating device (CSS-450) with a shear rate of 1000 / second. The temperature at which the temperature rises at 5 ° C./min and the objective lens 60 times is measured, and the temperature at which the entire field of view starts to flow can be obtained as the liquid crystal starting temperature.

  Among the melt kneading methods, a twin screw extruder is preferable. About a biaxial extruder, in order to improve the dispersibility of liquid crystalline polyester and glass fiber, it is preferable to provide one or more kneading parts, and it is more preferable to provide two or more places. For example, when glass fiber is added from the side feeder, the kneading portion is installed at one or more locations upstream of the glass fiber side feeder in order to promote plasticization of the liquid crystalline polyester. In order to improve the dispersibility with the fiber, it is preferable to install two or more places, one or more places, on the downstream side of the side feeder. The total L / D of the kneading part is preferably in the range of 16 to 28% of the total L / D of the screw. By making the total L / D of the kneading parts in each part 16 to 28% of the total L / D of the screw, the dispersibility of the glass fiber is improved and the amount of gas generation can be further reduced. The adhesion between the liquid crystalline polyester and the glass fiber can be improved. The total L / D of the kneading part is more preferably 20% or more of the total L / D of the screw because the dispersibility of the glass fiber can be improved. Moreover, it is more preferable to set it to 26% or less because thermal deterioration can be further reduced with excellent dispersibility. Moreover, the rotation speed of a screw is not specifically limited, It is preferable to set it as the appropriate conditions chosen from 50-1000 rpm.

  Further, in order to suppress thermal deterioration of the liquid crystalline polyester resin composition due to shear heat generation at the kneading portion in the above range, the resin temperature of the kneading portion is preferably set to the melting point of the liquid crystalline polyester + 10 ° C. or lower. By controlling the use ratio and temperature in the screw of the kneading part within the above range, it is excellent in the dispersibility of the glass fiber in the liquid crystalline polyester resin composition and can suppress an increase in the amount of gas generated due to thermal deterioration. It is preferable because the adhesion between the liquid crystalline polyester and the glass fiber is improved and the water vapor barrier property is specifically improved. Further, as the amount of generated gas is reduced, the variation in the cushion amount during molding is reduced and the molding stability is excellent, which is preferable.

  When the use ratio of the kneading part is larger than 16%, an increase in the amount of gas generated due to deterioration of the liquid crystalline polyester due to shearing heat generation and deterioration of the surface treatment agent of the glass fiber are suppressed. It is preferable because it has excellent adhesion to glass fibers, water vapor barrier properties, and cushion amount variation during molding. On the other hand, when the use ratio of the kneading part is smaller than 28%, the glass fiber can be dispersed while suppressing the heat deterioration due to the shear heat generation, and the adhesion between the liquid crystalline polyester and the glass fiber is excellent, and the water vapor barrier This is preferable because of improved properties. In addition, by controlling the resin temperature of the kneading part to the melting point of the liquid crystalline polyester + 10 ° C. or less, it is possible to suppress the thermal deterioration of the liquid crystalline polyester due to the shear heat generation in the kneading part. It is preferable because it has excellent adhesion to water and water vapor barrier properties.

  When controlling the usage rate of the kneading part and the resin temperature within the above ranges, the shear heat generation in the kneading part can suppress the promotion of thermal degradation of the liquid crystalline polyester, and the adhesion between the liquid crystalline polyester and the glass fiber. Is improved, and the water vapor barrier property is improved. In addition, even when using a liquid crystalline polyester excellent in water vapor barrier properties in a non-reinforced system, if the use ratio of the kneading part at the time of compounding and the resin temperature are within the above range, the dispersibility of the glass fiber is reduced, Since an increase in the amount of gas generated due to thermal deterioration is suppressed, the resulting liquid crystalline polyester resin composition is preferable because it has excellent water vapor barrier properties, an increase in the amount of gas generated during melt residence, and a variation in cushion amount during molding.

  As the kneading method, 1) a method in which liquid crystalline polyester (A) and glass fiber (B), other fillers and additives are added in a lump from the original feeder and kneaded (collective kneading method), and 2) liquid crystal A method in which glass fiber (B), other fillers, and additives are added from a side feeder and kneaded after adding the functional polyester (A) and the additive from the original feeder and kneading (side feed method), 3 ) Master pellets containing a high concentration of liquid crystalline polyester (A) and other additives are prepared, and then the master pellets are kneaded with the liquid crystalline polyester (A) and the glass fiber (B) filler so as to have a prescribed concentration. Any method may be used, such as a method to perform (master pellet method).

  The liquid crystalline polyester resin composition of the embodiment of the present invention has an excellent surface appearance by performing known melt molding such as injection molding, injection compression molding, compression molding, extrusion molding, blow molding, press molding, spinning, etc. Color) and mechanical properties, heat resistance and flame retardancy. Examples of the molded product include injection molded products, extrusion molded products, press molded products, sheets, pipes, unstretched films, uniaxially stretched films, various films such as biaxially stretched films, unstretched yarns, superstretched yarns, and the like. Examples include various fibers. In particular, injection molding is preferred from the viewpoint of processability.

  Molded articles made of the liquid crystalline polyester resin composition thus obtained include, for example, various gears, various cases, sensors, LED lamps, connectors, sockets, resistors, relay cases, relay bases, relay spools, switches, Coil bobbin, condenser, variable capacitor case, optical pickup, oscillator, various terminal boards, transformer, plug, printed wiring board, tuner, speaker, microphone, headphones, small motor, magnetic head base, power module, housing, semiconductor, liquid crystal display Parts, FDD carriages, FDD chassis, HDD parts, motor brush holders, parabolic antennas, thermal protectors, electrical and electronic parts such as computer-related parts; VTR parts, TV parts, Iro , Hair dryer, rice cooker parts, microwave oven parts, acoustic parts, audio equipment parts such as audio / laser discs (registered trademark) / compact discs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts, etc. Household / office electrical product parts; office computer-related parts, telephone-related parts, facsimile-related parts, copier-related parts, cleaning jigs, oilless bearings, stern bearings, submersible bearings, motor parts, lighters , Machine-related parts typified by typewriters, optical equipment typified by microscopes, binoculars, cameras, watches, precision machine-related parts; alternator terminals, alternator connectors, IC regulators, light dimmer potentiometer bases, exhaust gas Various valves such as valves, various pipes related to fuel, exhaust system, intake system, air intake nozzle snorkel, intake manifold, fuel pump, engine coolant joint, carburetor main body, carburetor spacer, exhaust gas sensor, coolant sensor, oil temperature Sensor, throttle position sensor, crankshaft position sensor, air flow meter, brake butt wear sensor, thermostat base for air conditioner, motor insulator for air conditioner, automotive motor insulator such as power window, heating hot air flow control valve, brush for radiator motor Holder, water pump impeller, turbine vane, wiper motor related parts, distributor, starter Switch, starter relay, transmission wiring harness, window washer nozzle, air conditioner panel switch board, coil for fuel solenoid valve, fuse connector, horn terminal, electrical component insulation plate, step motor rotor, lamp bezel, lamp socket, lamp reflector , Lamp housings, brake pistons, solenoid bobbins, engine oil filters, ignition device cases, and other automotive and vehicle-related parts; bottles for various chemicals such as shampoos, rinses, liquid soaps, detergents, etc .; chemical storage tanks, gas storage tanks, Liquid and gas storage tanks such as coolant tanks, oil transfer tanks, disinfectant tanks, transfusion pump tanks, fuel tanks, canisters, washer liquid tanks, oil reservoir tanks, etc. Ingredient use parts: seasonings such as soy sauce, sauce, ketchup, mayonnaise, dressing, fermented food such as miso and vinegar, fat and oil food such as salad oil, sake, beer, mirin, whiskey, shochu, wine and other alcoholic beverages, carbonated beverages, Food storage containers such as juices, sports drinks, milk, coffee drinks, soft drinks such as oolong tea, tea, and mineral water; and tanks, bottle-shaped molded products, or hollow containers such as those tanks as parts of general living utensils Can be used.

  The molded article of the present invention is useful for containers used for storage, transportation, and storage of various liquids by taking advantage of excellent molding processability and water vapor barrier properties among the various uses described above.

  Hereinafter, although an example explains the present invention still in detail, the gist of the present invention is not limited only to the following example.

The liquid crystalline polyester (A) used in each example and comparative example is shown below.
The composition analysis and characteristic evaluation of the liquid crystalline polyester were performed by the following methods.

(1) Composition Analysis of composition analysis liquid crystalline polyester of the liquid crystalline polyester ^was carried out by 1 H- nuclear magnetic resonance spectrum ⁽¹ H-NMR) measurement. 50 mg of liquid crystalline polyester was weighed in an NMR sample tube, dissolved in 800 μL of a solvent (mixed solvent of pentafluorophenol / 1,1,2,2-tetrachloroethane-d ₂ = 65/35 (weight ratio)), and unity INOVA500. ¹ H-NMR measurement was performed at an observation frequency of 500 MHz and a temperature of 80 ° C. using a type NMR apparatus (manufactured by Varian), and the composition was analyzed from the peak area ratio derived from each structural unit observed in the vicinity of 7 to 9.5 ppm. did.

(2) Melting point (Tm) measurement of liquid crystalline polyester Endothermic peak observed when measuring liquid crystalline polyester from room temperature to 20 ° C./min with a differential scanning calorimeter DSC-7 (manufactured by PerkinElmer). After observing the temperature (Tm ₁ ), holding at a temperature of Tm ₁ + 20 ° C. for 5 minutes, once cooling to room temperature under a temperature drop condition of 20 ° C./min, and measuring again under a temperature rise condition of 20 ° C./min The observed endothermic peak temperature (Tm ₂ ) was taken as the melting point. In the following production examples, the melting point is described as Tm.

(3) Generated gas amount of liquid crystalline polyester Using thermogravimetric analyzer TGA-7 (manufactured by PerkinElmer), the amount of weight loss when the liquid crystalline polyester was held at the melting point of the liquid crystalline polyester + 10 ° C. for 30 minutes, The amount of generated gas was determined.

(4) Melt viscosity measurement of liquid crystalline polyester Koka flow tester CFT-500D (orifice 0.5φ × 10 mm) (manufactured by Shimadzu Corporation) was used, the temperature was the melting point of liquid crystalline polyester + 10 ° C., and the shear rate was 1000 / sec. Measured with

  Moreover, about the manufacture examples 1 and 2, the following evaluation was performed.

(5) Evaluation of water vapor permeability After the pellets obtained in Production Examples 1 and 2 were dried at 150 ° C. for 3 hours using a hot air dryer, they were subjected to a FANUC α30C injection molding machine (manufactured by FANUC, screw diameter 28 mm). A test piece having a length of 70 mm, a width of 70 mm, and a thickness of 1 mm (fin gate) was prepared at a cylinder temperature of 330 ° C. and a mold temperature of 90 ° C. About the obtained test piece, based on JISK7129 (Appendix C, 2008), water vapor permeability was measured using GTR-30XATK (manufactured by GTR Tech) at a temperature of 80 ° C. and a relative humidity of 40%. .

Production Example 1 Liquid crystalline polyester resin (A-1)
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 870 parts by weight of p-hydroxybenzoic acid, 292 parts by weight of 4,4′-dihydroxybiphenyl, 125 parts by weight of hydroquinone, 292 parts by weight of terephthalic acid, 157 parts by weight of isophthalic acid And 1302 parts by weight of acetic anhydride (1.09 equivalents of total phenolic hydroxyl groups) were allowed to react at 145 ° C. for 1 hour with stirring under a nitrogen gas atmosphere, and the jacket temperature was changed from 145 ° C. to 330 ° C. for 4 hours. The temperature was raised at. Thereafter, the polymerization temperature was maintained at 330 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. Liquid crystalline polyester (A-1) was obtained.

Composition analysis of this liquid crystalline polyester (A-1) revealed that a structural unit derived from p-hydroxybenzoic acid (structural unit (I)) and a structural unit derived from 4,4′-dihydroxybiphenyl (structural unit (II )) And the structural unit derived from p-hydroxybenzoic acid (structural unit (I)) relative to the sum of the structural units derived from hydroquinone (structural unit (III)) was 70 mol%. 4,4′-dihydroxybiphenyl-derived structural unit (structural unit (II)) and hydroquinone-derived structural unit (structural unit (III)) relative to the total of 4,4′-dihydroxybiphenyl-derived structural unit (structural unit (II )) Was 58 mol%. The ratio of the structural unit derived from terephthalic acid (structural unit (IV)) to the total of the structural unit derived from terephthalic acid (structural unit (IV)) and the structural unit derived from isophthalic acid (structural unit (V)) is 65 mol%. Met. Total of structural units derived from 4,4′-dihydroxybiphenyl (structural unit (II)) and structural units derived from hydroquinone (structural unit (III)), structural units derived from terephthalic acid (structural unit (IV)) and isophthal The sum of the structural units derived from the acid (structural unit (V)) was substantially equimolar. Moreover, Tm was 310 degreeC, the amount of generated gas was 0.08 weight%, and the melt viscosity was 30 Pa.s. Further, the water vapor permeability at a temperature of 80 ° C. and a relative humidity of 40% was 0.0495 g / m ² · 24 hr · atm.

Production Example 2 Liquid crystalline polyester (A-2)
Production Example 1 except that the temperature is controlled while controlling the temperature so that the time from 200 ° C. to 270 ° C. is 85 minutes in the temperature increase of 4 hours from 145 ° C. to 330 ° C. Polymerization was carried out in the same manner as above to obtain liquid crystalline polyester (A-2) pellets.

The composition of the liquid crystalline polyester (A-2) was analyzed, and the ratio of the structural unit (I) to the total of the structural unit (I), the structural unit (II), and the structural unit (III) was 70 mol%. there were. The ratio of the structural unit (II) to the total of the structural unit (II) and the structural unit (III) was 58 mol%. The ratio of the structural unit (IV) to the total of the structural unit (IV) and the structural unit (V) was 65 mol%. The total of the structural unit (II) and the structural unit (III) and the total of the structural unit (IV) and the structural unit (V) were substantially equimolar. Moreover, Tm was 310 degreeC, the amount of generated gas was 0.08 weight%, and the melt viscosity was 30 Pa.s. The water vapor transmission rate at a temperature of 80 ° C. and a relative humidity of 40% was 0.0358 g / m ² · 24 hr · atm.

Production Example 3 Liquid crystalline polyester resin (A-3)
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 932 parts by weight of p-hydroxybenzoic acid, 251 parts by weight of 4,4′-dihydroxybiphenyl, 99 parts by weight of hydroquinone, 284 parts by weight of terephthalic acid, 90 parts by weight of isophthalic acid And 1252 parts by weight of acetic anhydride (1.09 equivalents of the total phenolic hydroxyl groups) were allowed to react at 145 ° C. for 1 hour with stirring under a nitrogen gas atmosphere, and the jacket temperature was increased from 145 ° C. to 350 ° C. for 4 hours. The temperature was raised at. Thereafter, the polymerization temperature was maintained at 350 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. A liquid crystalline polyester (A-3) was obtained.

  When the composition analysis was performed on this liquid crystalline polyester (A-3), the ratio of the structural unit (I) to the total of the structural unit (I), the structural unit (II), and the structural unit (III) was 75 mol%. there were. The ratio of the structural unit (II) to the total of the structural unit (II) and the structural unit (III) was 60 mol%. The ratio of the structural unit (IV) to the total of the structural unit (IV) and the structural unit (V) was 76 mol%. The total of the structural unit (II) and the structural unit (III) and the total of the structural unit (IV) and the structural unit (V) were substantially equimolar. Further, Tm was 330 ° C., the amount of generated gas was 0.12% by weight, and the melt viscosity was 28 Pa · s.

Production Example 4 Liquid crystalline polyester resin (A-4)
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 907 parts by weight of p-hydroxybenzoic acid, 371 parts by weight of 4,4′-dihydroxybiphenyl, 48 parts by weight of hydroquinone, 230 parts by weight of terephthalic acid, 174 parts by weight of isophthalic acid And 1,272 parts by weight of acetic anhydride (1.09 equivalent of the total phenolic hydroxyl groups) were reacted at 145 ° C. for 1 hour with stirring under a nitrogen gas atmosphere, and the jacket temperature was changed from 145 ° C. to 335 ° C. for 4 hours. The temperature was raised at. Thereafter, the polymerization temperature was maintained at 335 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. Liquid crystalline polyester (A-4) was obtained.

  When the composition analysis was performed on this liquid crystalline polyester (A-4), the ratio of the structural unit (I) to the total of the structural unit (I), the structural unit (II), and the structural unit (III) was 73 mol%. there were. The ratio of the structural unit (II) to the total of the structural unit (II) and the structural unit (III) was 82 mol%. The ratio of the structural unit (IV) to the total of the structural unit (IV) and the structural unit (V) was 57 mol%. The total of the structural unit (II) and the structural unit (III) and the total of the structural unit (IV) and the structural unit (V) were substantially equimolar. Further, Tm was 315 ° C., the amount of gas generated was 0.22 wt%, and the melt viscosity was 24 Pa · s.

Production Example 5 Liquid crystalline polyester resin (A-5)
845 parts by weight of p-hydroxybenzoic acid, 402 parts by weight of 4,4′-dihydroxybiphenyl, 79 parts by weight of hydroquinone, 258 parts by weight of terephthalic acid, 220 parts by weight of isophthalic acid in a 5 L reaction vessel equipped with a stirring blade and a distillation pipe And 1322 parts by weight of acetic anhydride (1.09 equivalent of total phenolic hydroxyl groups) were allowed to react at 145 ° C. for 1 hour with stirring in a nitrogen gas atmosphere, and the jacket temperature was changed from 145 ° C. to 320 ° C. for 4 hours. The temperature was raised at. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. Liquid crystalline polyester (A-5) was obtained.

  As a result of composition analysis of the liquid crystalline polyester (A-5), the ratio of the structural unit (I) to the total of the structural unit (I), the structural unit (II), and the structural unit (III) was 68 mol%. there were. The ratio of the structural unit (II) to the total of the structural unit (II) and the structural unit (III) was 75 mol%. The ratio of the structural unit (IV) to the total of the structural unit (IV) and the structural unit (V) was 54 mol%. The total of the structural unit (II) and the structural unit (III) and the total of the structural unit (IV) and the structural unit (V) were substantially equimolar. Further, Tm was 301 ° C., the amount of gas generated was 0.19 wt%, and the melt viscosity was 18 Pa · s.

Production Example 6 Liquid crystalline polyester resin (A-6)
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 845 parts by weight of p-hydroxybenzoic acid, 467 parts by weight of 4,4′-dihydroxybiphenyl, 41 parts by weight of hydroquinone, 201 parts by weight of terephthalic acid, 278 parts by weight of isophthalic acid And 1322 parts by weight of acetic anhydride (1.09 equivalents of the total phenolic hydroxyl groups) were allowed to react at 145 ° C. for 1 hour with stirring under a nitrogen gas atmosphere, and the jacket temperature was changed from 145 ° C. to 290 ° C. for 4 hours. The temperature was raised at. Thereafter, the polymerization temperature was maintained at 290 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. Liquid crystalline polyester (A-6) was obtained.

  As a result of composition analysis of the liquid crystalline polyester (A-6), the ratio of the structural unit (I) to the total of the structural unit (I), the structural unit (II), and the structural unit (III) was 68 mol%. there were. The ratio of the structural unit (II) to the total of the structural unit (II) and the structural unit (III) was 87 mol%. The ratio of the structural unit (IV) to the total of the structural unit (IV) and the structural unit (V) was 42 mol%. The total of the structural unit (II) and the structural unit (III) and the total of the structural unit (IV) and the structural unit (V) were substantially equimolar. Further, Tm was 262 ° C., the amount of gas generated was 0.26 wt%, and the melt viscosity was 20 Pa · s.

Production Example 7 Liquid crystalline polyester resin (A-7)
957 parts by weight of p-hydroxybenzoic acid, 193 parts by weight of 4,4′-dihydroxybiphenyl, 114 parts by weight of hydroquinone, 258 parts by weight of terephthalic acid, 86 parts by weight of isophthalic acid in a 5 L reaction vessel equipped with a stirring blade and a distillation pipe And 1232 parts by weight of acetic anhydride (1.09 equivalents of the total phenolic hydroxyl groups) were allowed to react at 145 ° C. for 1 hour with stirring in a nitrogen gas atmosphere, and the jacket temperature was increased from 145 ° C. to 350 ° C. for 4 hours. The temperature was raised at. Thereafter, the polymerization temperature was maintained at 350 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. Liquid crystalline polyester (A-7) was obtained.

  As a result of composition analysis of the liquid crystalline polyester (A-7), the ratio of the structural unit (I) to the total of the structural unit (I), the structural unit (II), and the structural unit (III) was 77 mol%. there were. The ratio of the structural unit (II) to the total of the structural unit (II) and the structural unit (III) was 50 mol%. The ratio of the structural unit (IV) to the total of the structural unit (IV) and the structural unit (V) was 75 mol%. The total of the structural unit (II) and the structural unit (III) and the total of the structural unit (IV) and the structural unit (V) were substantially equimolar. The Tm was 328 ° C., the amount of gas generated was 0.25% by weight, and the melt viscosity was 22 Pa · s.

Production Example 8 Liquid crystalline polyester resin (A-8)
In a 5 L reaction vessel equipped with a stirring blade and a distilling tube, 994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4′-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g 216 parts by weight of polyethylene terephthalate and 960 parts by weight of acetic anhydride (1.10 equivalents of total phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 1 hour with stirring under a nitrogen gas atmosphere. The temperature was raised in 4 hours. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. Liquid crystalline polyester (A-8) was obtained.

  Composition analysis of this liquid crystalline polyester (A-8) revealed that the structural unit (I) was 66.7 mol%, the structural unit (II) was 6.3 mol%, and the ethylenedioxy unit derived from polyethylene terephthalate was The content was 10.4 mol% and the structural unit (IV) was 16.6 mol%. The Tm was 313 ° C., the amount of gas generated was 0.30% by weight, and the melt viscosity was 13 Pa · s.

Production Example 9 Liquid crystalline polyester resin (A-9)
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 25 parts by weight of p-hydroxybenzoic acid, 813 parts by weight of 6-hydroxy-2-naphthoic acid, 419 parts by weight of 4,4′-dihydroxybiphenyl, 374 terephthalic acid 1 part by weight and 965 parts by weight of acetic anhydride (1.05 equivalents of total phenolic hydroxyl groups) were allowed to react at 145 ° C. for 1 hour with stirring in a nitrogen gas atmosphere, and then from 145 ° C. to 360 ° C. over 4 hours. The temperature was raised. Thereafter, the polymerization temperature was maintained at 360 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hour, the reaction was continued, and the polymerization was completed when the torque required for stirring reached 20 kg · cm. Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. Liquid crystalline polyester (A-9) was obtained.

  Composition analysis of this liquid crystalline polyester (A-9) revealed that the structural unit (I) was 2 mol%, the 6-oxy-2-naphthalate unit was 48 mol%, the structural unit (II) was 25 mol%, and the structure The unit (IV) was 25 mol%. Further, Tm was 350 ° C., the amount of gas generated was 0.28 wt%, and the melt viscosity was 25 Pa · s.

The filler (B) used in each example and comparative example is shown below.
(B-1): Nippon Electric Glass Chopped Strand (T-747H)
(B-2): Nippon Electric Glass glass milled fiber (EPDE-40M-10A)

Examples 1-11, Comparative Examples 1-6
A TEM35B type twin screw extruder manufactured by Toshiba Machine equipped with a side feeder. A side feeder is installed in C3 of cylinder C1 (original feeder heater) to C6 (die heater), and a vacuum vent is installed in C5. did. Liquid crystallinity obtained in each production example using a screw arrangement in which kneading blocks are incorporated in C2 part and C4 part and the ratio of L / D of all kneading parts in screw L / D is as shown in Table 1. The polyester resins (A-1 to A-9) are charged from the hopper, and the fillers (B-1, B-2) are charged from the side at the blending amounts shown in Table 1, and the cylinder temperatures are C2 and C4. The installed resin thermometer was appropriately set so as to have the resin temperature shown in Table 1, and melt kneaded at a screw rotation speed of 150 rpm to obtain pellets. After the pellets of the obtained liquid crystalline polyester resin composition were dried with hot air, the following evaluations (1) to (3) were performed. The results are shown in Table 1.

(1) Evaluation of water vapor permeability After the pellets obtained in each of the examples and comparative examples were dried at 150 ° C. for 3 hours using a hot air dryer, they were put into a FANUC α30C injection molding machine (manufactured by FANUC, screw diameter 28 mm). A test piece having a length of 70 mm, a width of 70 mm, and a thickness of 1 mm (fin gate) was prepared by setting the cylinder temperature to the melting point of liquid crystalline polyester + 20 ° C. and the mold temperature to 90 ° C. About the obtained test piece, based on JISK7129 (Appendix C, 2008), water vapor permeability was measured using GTR-30XATK (manufactured by GTR Tech) at a temperature of 80 ° C. and a relative humidity of 40%. .

(2) Evaluation of increase in amount of gas generated during melt residence After pellets obtained in each Example and Comparative Example were dried at 150 ° C. for 3 hours using a hot air dryer, thermogravimetric analyzer TGA-7 (Perkin Elmer) The weight loss when the liquid crystalline polyester was kept at the melting point + 10 ° C. for 30 minutes was measured and used as the amount of gas generated before melt retention. In addition, after being held for 10 minutes at the melting point of liquid crystalline polyester + 10 ° C. in the furnace of Koka-type flow tester CFT-500D (orifice 0.5φ × 10 mm) (manufactured by Shimadzu Corporation) The weight loss when the liquid crystalline polyester was held at the melting point + 10 ° C. for 30 minutes was measured and used as the amount of gas generated after the melt residence. The difference in the amount of gas generated before melt residence with respect to the amount of gas generated after melt residence was evaluated as the amount of generated gas increase during residence.

(3) Cushion amount evaluation during molding After pellets obtained in each Example and Comparative Example were dried at 150 ° C. for 3 hours using a hot air dryer, a FANUC α30C injection molding machine (manufactured by FANUC, screw diameter 28 mm) The rod-shaped molded product 127 mm long × 12.7 mm wide × 3.2 mm thick was molded into 50 shots with the cylinder temperature set to the melting point of liquid crystalline polyester + 20 ° C. and the mold temperature set to 90 ° C. Cylinder cushion amount of each shot at that time (the amount of resin left at the tip of the molding machine cylinder to suppress defects such as sink marks on the molded product, expressed by the screw position from the cylinder tip position (0 mm)) (Maximum value−minimum value) was measured. It was evaluated that the smaller the variation in the cushion amount, the better the molding stability.

  From the results shown in Table 1, the liquid crystalline polyester resin composition of the embodiment of the present invention has excellent water vapor barrier properties, little increase in the amount of gas generated during melt residence, and small variation in cushion amount during molding. This shows that the moldability is excellent. Therefore, it turns out that it is suitable for the use for the container use as which suppression of water vapor | steam transmission is requested | required.

  The liquid crystalline polyester resin composition of the present invention has a high water vapor barrier property, a small increase in gas generation during melt residence, and excellent molding stability. Useful for.

Claims (4)

Liquid crystal containing 10 to 200 parts by weight of glass fiber (B) with respect to 100 parts by weight of liquid crystalline polyester (A) comprising the following structural units (I), (II), (III), (IV) and (V) A water-soluble polyester resin composition having a water vapor transmission rate of not more than 0.05 g / m ² · 24 hr · atm at a temperature of 80 ° C. and a relative humidity of 40%, and at the melting point of the liquid crystalline polyester + 10 ° C. for 10 minutes The liquid crystal polyester resin composition is characterized in that the amount of gas generated in the above is 0.2% by weight or less from the amount of gas generated before melt retention.

In the liquid crystalline polyester (A), the structural unit (I) is 65 to 80 mol% based on the total of the structural units (I), (II) and (III), and the structural unit (II) is the structural unit (II). ) And (III) is 55 to 85 mol%, the structural unit (IV) is 50 to 95 mol% with respect to the total of the structural units (IV) and (V), and the structural unit (II 2. The liquid crystalline polyester resin composition according to claim 1, wherein the sum of (II) and (III) and the sum of (IV) and (V) are substantially equimolar. The amount of gas generated by the liquid crystalline polyester (A) (the melting point of the liquid crystalline polyester + the weight loss when held at 10 ° C. for 30 minutes) is 0.2% by weight or less. Liquid crystalline polyester resin composition. A molded product obtained by molding the liquid crystalline polyester resin composition according to claim 1.