JP2024004009A - Polybutylene terephthalate resin composite and method for producing polybutylene terephthalate resin composite - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polybutylene terephthalate resin composite capable of improving hydrolysis resistance and measuring properties.

SOLUTION: There is provided a polybutylene terephthalate resin composite containing polybutylene terephthalate resin composition pellets and an external additive, wherein the polybutylene terephthalate resin composition pellets contain a polybutylene terephthalate resin having a terminal carboxyl group content of 30 meq/kg or less and a carbodiimide compound in an amount of 0.1 to 1.0 mass% of the total mass of the polybutylene terephthalate resin composite, and the external additive contains a fatty acid metal salt having a number average particle diameter of 20 μm or less in an amount of 0.005 to 0.10 mass% of the total mass of the polybutylene terephthalate resin composite.

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

Embodiments of the present invention relate to polybutylene terephthalate resin composites and methods for producing polybutylene terephthalate resin composites.

Polyester resins such as polybutylene terephthalate resin (hereinafter also referred to as "PBT resin") have excellent mechanical properties, electrical properties, heat resistance, and moldability, and are used for automobile parts, electrical and electronic equipment parts, and precision equipment. It is widely used in various fields such as parts. Since polyester resins have ester groups in their molecules, they are susceptible to hydrolysis in high-temperature, humid environments, and there is always a desire for improved hydrolysis resistance in automotive parts that are subject to large environmental changes.

In order to improve the hydrolysis resistance of polyester resin itself, it is generally known to add an epoxy resin or a carbodiimide compound to reduce the amount of terminal carboxyl groups. Patent Document 1 describes a resin composition in which a polybutylene terephthalate resin having a terminal carboxyl group content of 30 meq/kg or less, a carbodiimide compound, a fibrous filler, and an elastomer is blended, and the carbodiimide compound is added to the polybutylene terephthalate resin. It has been shown that when the terminal carboxyl group amount is 1, heat shock resistance and hydrolysis resistance are improved by blending the carbodiimide functional group amount in an amount of 0.3 to 1.5 equivalents. There is.

On the other hand, as a method for obtaining molded products using polyester resin, extrusion molding and injection molding are often adopted in terms of productivity and cost. Polyester resins are susceptible to hydrolysis, so they are generally dried before use, but during this drying process, a phenomenon called blocking or sticking, in which pellets stick to each other, may occur. This generally tends to occur when the elastic modulus, glass transition temperature, or crystallinity of the resin composition is low. For example, after feeding dried pellets into the hopper of an extrusion molding machine or injection molding machine, Blocking or sticking may occur due to the weight of the pellets, or problems may arise where the pellets are stuck at the screw opening and cannot be molded. Further, when weighing pellets with a screw, the screw may idle due to stuck pellets, or measurement errors may occur due to poor conveyance of the pellets. Furthermore, depending on the shape of the pellets, the cylinder may not have enough heat or the pellets may not penetrate properly, resulting in failure to plasticize and poor metering.

Patent Document 2 describes that sticking can be suppressed by crystallizing resin pellets by heating them at a temperature that is higher than the cold crystallization temperature and 30° C. lower than the melting point.
Patent Document 3 describes that in an elliptical columnar thermoplastic aromatic polyester resin pellet, the major axis/minor axis ratio of a cross section perpendicular to the longitudinal direction is >1, the bulk density is >0.8 g/cm ³ , and 0.4≦excluded volume density. It is stated that in the case of <0.5 g/cm ³ , variations in metrology can be suppressed.
Patent Document 4 discloses that calcium stearate or the like is added as an external lubricant to polybutylene terephthalate chips in order to improve chip bite into the screw of an injection molding machine, and that an external lubricant is added to polybutylene terephthalate chips. It is described that the fine powder can be removed while the external lubricant remains attached in an amount of 200 to 500 ppm by weight per chip by removing the fine powder with an air classifier after the above.

International Publication No. 2009/150831 Japanese Patent Application Publication No. 5-147026 Japanese Patent Application Publication No. 2015-044363 Japanese Patent Application Publication No. 6-285850

An object of the embodiments of the present invention is to provide a polybutylene terephthalate resin composite that can improve hydrolysis resistance and improve meterability.

One embodiment of the present invention is a polybutylene terephthalate resin composite comprising polybutylene terephthalate resin composition pellets and an external additive, wherein the polybutylene terephthalate resin composition pellets have a terminal carboxyl group content of 30 meq/ kg or less of polybutylene terephthalate resin, and 0.1 to 1.0% by mass of a carbodiimide compound based on the total mass of the polybutylene terephthalate resin composite, and the external additive is a polybutylene terephthalate resin composite. The present invention relates to a polybutylene terephthalate resin composite containing 0.005 to 0.10% by mass of a fatty acid metal salt having a number average particle diameter of 20 μm or less based on the total mass.
Another embodiment of the present invention relates to a method for producing the polybutylene terephthalate resin composite, which includes mixing the polybutylene terephthalate resin composition pellets and the external additive.

According to the embodiments of the present invention, it is possible to provide a polybutylene terephthalate resin composite that can improve hydrolysis resistance and improve meterability.

Preferred embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.

<Polybutylene terephthalate resin composite>
A polybutylene terephthalate resin composite according to an embodiment of the present invention includes polybutylene terephthalate resin composition pellets and an external additive, and the polybutylene terephthalate resin composition pellets have a terminal carboxyl group content of 30 meq/kg or less. of polybutylene terephthalate resin and a carbodiimide compound of 0.1 to 1.0 mass% of the total mass of the polybutylene terephthalate resin composite, and the external additive is 0.1 to 1.0 mass% of the total mass of the polybutylene terephthalate resin composite. 0.005 to 0.10% by mass of fatty acid metal salts with a number average particle diameter of 20 μm or less.

[Polybutylene terephthalate resin (PBT resin)]
In the polybutylene terephthalate resin composite of the embodiment, the polybutylene terephthalate resin composition pellets contain a polybutylene terephthalate resin having a terminal carboxyl group content of 30 meq/kg or less.

The polybutylene terephthalate resin contains a dicarboxylic acid component containing at least terephthalic acid or its ester-forming derivative (C _1-6 alkyl ester, acid halide, etc.) and an alkylene glycol having at least 4 carbon atoms (1,4-butane). It is a polybutylene terephthalate resin obtained by polycondensation with a glycol component containing diol) or its ester-forming derivative (acetylated product, etc.).
The polybutylene terephthalate resin is not limited to a homopolybutylene terephthalate resin, but may be a copolymer containing 60 mol% or more (particularly 75 mol% or more and 95 mol% or less) of butylene terephthalate units.

In the polybutylene terephthalate resin, dicarboxylic acid components (comonomer components) other than terephthalic acid and its ester-forming derivatives include, for example, isophthalic acid, phthalic acid, 2,6-naphthalene dicarboxylic acid, and 4,4'-dicarboxydiphenyl ether. C _8-14 aromatic dicarboxylic acids such as; C _4-16 alkanedicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid; C _5-10 cycloalkanedicarboxylic acids such as cyclohexanedicarboxylic acid; Examples include ester-forming derivatives of dicarboxylic acid components (C _1-6 alkyl ester derivatives, acid halides, etc.). These dicarboxylic acid components can be used alone or in combination of two or more.

Among these dicarboxylic acid components, C _8-12 aromatic dicarboxylic acids such as isophthalic acid, and C _6-12 alkanedicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid are more preferred.

In the polybutylene terephthalate resin, examples of glycol components (comonomer components) other than 1,4-butanediol include ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butylene glycol, hexamethylene glycol, neopentyl glycol, _C2-10 alkylene glycols such as 1,3-octanediol; polyoxyalkylene glycols such as diethylene glycol, triethylene glycol, and dipropylene glycol; alicyclic diols such as cyclohexanedimethanol and hydrogenated bisphenol A; bisphenol A, Aromatic diols such as 4,4'-dihydroxybiphenyl; _C2-4 alkylene oxide adducts of bisphenol A, such as 2-mole ethylene oxide adducts of bisphenol A, and 3-mole propylene oxide adducts of bisphenol A; or these. Examples include ester-forming derivatives (acetylated products, etc.) of glycols. These glycol components can be used alone or in combination of two or more.

Among these glycol components, _C2-6 alkylene glycols such as ethylene glycol and trimethylene glycol, polyoxyalkylene glycols such as diethylene glycol, or alicyclic diols such as cyclohexanedimethanol are more preferred.

Comonomer components that can be used in addition to dicarboxylic acid components and glycol components include, for example, 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 4-carboxy-4'-hydroxybiphenyl, etc. Aromatic hydroxycarboxylic acids; aliphatic hydroxycarboxylic acids such as glycolic acid and hydroxycaproic acid; _C3-12 lactones such as propiolactone, butyrolactone, valerolactone, caprolactone (ε-caprolactone, etc.); esters of these comonomer components Formative derivatives (C _1-6 alkyl ester derivatives, acid halides, acetylated products, etc.) can be mentioned.

Any of the polybutylene terephthalate copolymers obtained by copolymerizing the comonomer components described above can be suitably used as the polybutylene terephthalate resin. Further, as the polybutylene terephthalate resin, a homopolybutylene terephthalate polymer and a polybutylene terephthalate copolymer may be used in combination.

The intrinsic viscosity (IV) of the polybutylene terephthalate resin is not particularly limited as long as it does not impede the effects of the polybutylene terephthalate resin composite of the embodiment. The intrinsic viscosity of the polybutylene terephthalate resin is preferably 0.7 to 1.3 dL/g, more preferably 0.75 to 1.2 dL/g, and 0.7 to 1.3 dL/g, more preferably 0.75 to 1.2 dL/g, from the viewpoint of processability and mechanical properties. More preferably, it is 85 to 1.15 dL/g.
The intrinsic viscosity can also be adjusted by blending polybutylene terephthalate resins having different intrinsic viscosities. For example, a polybutylene terephthalate resin with an intrinsic viscosity of 0.85 dL/g is prepared by blending a polybutylene terephthalate resin with an intrinsic viscosity of 1.0 dL/g and a polybutylene terephthalate resin with an intrinsic viscosity of 0.7 dL/g. Can be done.
The intrinsic viscosity (IV) of the polybutylene terephthalate resin is a value measured in o-chlorophenol at a temperature of 35°C.

From the viewpoint of hydrolysis resistance, the amount of terminal carboxyl groups in the polybutylene terephthalate resin is preferably 30 meq/kg or less, more preferably 20 meq/kg or less, and even more preferably 10 meq/kg or less.

[Carbodiimide compound]
In the polybutylene terephthalate resin composite of the embodiment, the polybutylene terephthalate resin composition pellets include a carbodiimide compound.

In the polybutylene terephthalate resin composite of the embodiment, the carbodiimide compound can contribute to improving hydrolysis resistance.

A carbodiimide compound is a compound having a carbodiimide group (-N=C=N-) in its molecule. Examples of the carbodiimide compound include an aliphatic carbodiimide compound having an aliphatic main chain, an alicyclic carbodiimide compound having an alicyclic main chain, and an aromatic carbodiimide compound having an aromatic main chain. One or more can be used. Among these, it is preferable to contain an aromatic carbodiimide compound in view of the heat resistance and moist heat resistance of the carbodiimide compound.

Examples of the aliphatic carbodiimide compound include diisopropylcarbodiimide, dioctyldecylcarbodiimide, and the like. Examples of the alicyclic carbodiimide compound include dicyclohexylcarbodiimide and the like. These can be used alone or in combination of two or more.

Aromatic carbodiimide compounds include diphenylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, N-triyl-N'-phenylcarbodiimide, di-p-nitrophenylcarbodiimide, di-p-aminophenylcarbodiimide, di-p- Hydroxyphenylcarbodiimide, di-p-chlorophenylcarbodiimide, di-p-methoxyphenylcarbodiimide, di-3,4-dichlorophenylcarbodiimide, di-2,5-dichlorophenylcarbodiimide, di-o-chlorophenylcarbodiimide, Mono- or dicarbodiimide compounds such as p-phenylene-bis-di-o-tolylcarbodiimide, p-phenylene-bis-dicyclohexylcarbodiimide, p-phenylene-bis-di-p-chlorophenylcarbodiimide, ethylene-bis-diphenylcarbodiimide, etc. ; and poly(4,4'-diphenylmethanecarbodiimide), poly(3,5'-dimethyl-4,4'-biphenylmethanecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly( 3,5'-dimethyl-4,4'-diphenylmethanecarbodiimide), poly(naphthylenecarbodiimide), poly(1,3-diisopropylphenylenecarbodiimide), poly(1-methyl-3,5-diisopropylphenylenecarbodiimide), poly Examples include polycarbodiimide compounds such as (1,3,5-triethylphenylenecarbodiimide) and poly(triisopropylphenylenecarbodiimide). These can be used alone or in combination of two or more.

The number average molecular weight of the carbodiimide compound is preferably 3000 or more. By setting the number average molecular weight within the above range, gas and odor can be prevented from being generated when the residence time is long during melt-kneading or molding of the thermoplastic resin.

In the polybutylene terephthalate resin composite of the embodiment, the content of the carbodiimide compound is 0.1 to 1.0% by mass of the total mass of the polybutylene terephthalate resin composite. From the viewpoint of improving hydrolysis resistance, the content of the carbodiimide compound is preferably 0.1% by mass or more based on the total mass of the polybutylene terephthalate resin composite. On the other hand, from the viewpoint of suppressing the generation of isocyanate, the content of the carbodiimide compound is preferably 1.0% by mass or less based on the total mass of the polybutylene terephthalate resin composite. The carbodiimide compound is more preferably 0.2 to 0.9% by mass, and even more preferably 0.3 to 0.8% by mass, based on the total mass of the polybutylene terephthalate resin composite.
The total content of the polybutylene terephthalate resin and the content of the carbodiimide compound is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, based on the total mass of the polybutylene terephthalate resin composite.

[Other components (polybutylene terephthalate resin composition pellets)]
The polybutylene terephthalate resin composition pellets may contain other components other than the above components, if necessary. Other components of the polybutylene terephthalate resin composition pellets include other resins, fillers such as inorganic fillers, antioxidants, stabilizers, antistatic agents, lubricants, plasticizers, crystal nucleating agents, colorants, Additives such as flame retardants and flame retardant aids can be mentioned, and one or more of these can be included in the polybutylene terephthalate resin composition pellets as necessary.

[Fatty acid metal salt]
The polybutylene terephthalate resin composite of the embodiment includes polybutylene terephthalate resin composition pellets and an external additive containing a fatty acid metal salt having a number average particle diameter of 20 μm. By using an external additive containing a fatty acid metal salt, the fatty acid metal salt is externally added to the surface of the polybutylene terephthalate resin composition pellet. Due to the action of the externally added fatty acid metal salt attached to the pellet surface, the measuring time can be shortened and the measuring performance can be improved. On the other hand, since polybutylene terephthalate resin has a polyester group, it is easily hydrolyzed by alkaline components and the like, and when a fatty acid metal salt is used, the hydrolysis resistance may decrease. However, when a fatty acid metal salt having a number average particle diameter of 20 μm is used as the fatty acid metal salt, it becomes possible to achieve both hydrolysis resistance and metricability.

Examples of fatty acid metal salts include alkali metal salts of fatty acids and alkaline earth metal salts of fatty acids. Specifically, examples of fatty acid metal salts include calcium salts of fatty acids, sodium salts of fatty acids, magnesium salts of fatty acids, zinc salts of fatty acids, and the like.
The fatty acid of the fatty acid metal salt is preferably a fatty acid having 8 to 30 carbon atoms, more preferably a fatty acid having 10 to 25 carbon atoms, and even more preferably a fatty acid having 13 to 21 carbon atoms. The fatty acid of the fatty acid metal salt is preferably a saturated fatty acid. Specific examples of the fatty acid of the fatty acid metal salt include caprylic acid, lauric acid, myristic acid, pentadecyl acid, palmitic acid, margaric acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, and melisic acid. Examples include acids.
Specific examples of fatty acid metal salts include sodium palmitate, calcium palmitate, sodium stearate, potassium stearate, zinc stearate, calcium stearate, magnesium stearate, calcium montanate, and the like. As the fatty acid metal salt, calcium stearate is preferred.

In the polybutylene terephthalate resin composite of the embodiment, the number average particle diameter of the fatty acid metal salt is 20 μm or less. The number average particle diameter of the fatty acid metal salt is more preferably 18 μm or less, and even more preferably 16 μm or less.

The number average particle size of the fatty acid metal salt is the number average particle size calculated by measuring the particle size distribution using a laser diffraction scattering type particle size distribution measuring device. As a measuring device, a laser diffraction scattering particle size distribution measuring device LA-960 manufactured by Horiba, Ltd. can be used. Specifically, a trace amount (approximately 10 to 20 mg) of fatty acid metal salt was placed in a 10 mL vial using a medicine spoon, 10 mL of acetone was added, and the mixture was sufficiently dispersed using an ultrasonic cleaner to obtain a laser diffraction scattering particle size distribution. The particle size distribution can be measured with a measuring device and the number average particle size can be calculated.

In embodiment composites, the amount of fatty acid metal salt is from 0.005 to 0.10% by weight of the total weight of the polybutylene terephthalate resin composite. From the viewpoint of improving metrology, the amount of the fatty acid metal salt is preferably 0.005% by mass or more based on the total mass of the polybutylene terephthalate resin composite. On the other hand, from the viewpoint of good toughness, the amount of the fatty acid metal salt is preferably 0.10% by mass or less based on the total mass of the polybutylene terephthalate resin composite. If there is too much fatty acid metal salt, the large amount of powder may actually cause poor measurement.
The amount of the fatty acid metal salt is more preferably 0.010 to 0.05% by mass, and even more preferably 0.02 to 0.03% by mass, based on the total mass of the polybutylene terephthalate resin composite.

[Other ingredients (external additives)]
The external additive may contain other components in addition to the above components, if necessary.
For example, the external additive may include a sticking agent to better adhere and retain the fatty acid metal salt on the surface of the polybutylene terephthalate resin composition pellet. Use of a sticking agent can improve the adhesion of the fatty acid metal salt to the pellets, and can also reduce the dropping of the fatty acid metal salt from the pellets, thereby reducing contamination of the apparatus.

Examples of the fixing agent include polyethylene glycol, liquid paraffin, paraffin wax, water, and glycerin. One type or two or more types of these can be used. Among these, polyethylene glycol is preferred.

The amount of the fixing agent is preferably 0.005 to 0.1% by mass, more preferably 0.01 to 0.05% by mass, and 0.01 to 0.03% by mass of the total mass of the polybutylene terephthalate resin composite. is even more preferable.

[Shape of polybutylene terephthalate resin composition pellet]
The diameter of the polybutylene terephthalate resin composition pellet is preferably 2.0 to 3.0 mm, more preferably 2.1 to 2.8 mm, and even more preferably 2.2 to 2.5 mm. preferable.
The length of the polybutylene terephthalate resin composition pellet is preferably 1.0 to 3.5 mm, more preferably 1.5 to 3.3 mm, and preferably 2.0 to 3.1 mm. More preferred.

<Method for producing polybutylene terephthalate resin composite>
The method for producing the polybutylene terephthalate resin composite described above is not particularly limited.
The method for producing the polybutylene terephthalate resin composite of the embodiment may be, for example, a method including mixing polybutylene terephthalate resin composition pellets and an external additive.

The method of mixing the polybutylene terephthalate resin composition pellets and the external additive is not particularly limited. For example, polybutylene terephthalate resin composition pellets and external additives can be mixed using a mixer such as a tumbler mixer. Further, the polybutylene terephthalate resin composition pellets and the external additive may be mixed all at once, or may be mixed in multiple batches. For example, when the external additive contains a sticking agent and a fatty acid metal salt, the polybutylene terephthalate resin composition pellets and the sticking agent may be mixed, and then this mixture and the metal salt oxide may be mixed.

Polybutylene terephthalate resin composition pellets can be produced by various methods known as methods for producing thermoplastic resin composition pellets. For example, polybutylene terephthalate resin composition pellets can be obtained by charging the materials for the polybutylene terephthalate resin composition pellets into an extruder, melt-kneading them, extruding them, and pelletizing them.

<Molded product>
There is no particular limitation on the method for producing a resin molded article using the polybutylene terephthalate resin composite of the embodiment, and any known method can be employed. For example, it can be produced by putting a polybutylene terephthalate resin composite into an injection molding machine equipped with a predetermined mold and performing injection molding.

As a resin molded article, it can be suitably used as a resin composition for a molded article that is exposed to a high temperature, high humidity environment for a long period of time, such as in automobiles, trains, and aviation industry applications. Molded products made from this resin composition can be prevented from deteriorating due to hydrolysis even when used for long periods in sufficiently high temperature and high humidity environments, so they can be used for connectors, housings, valves, clips, pipes, etc. It can be used for.

Although embodiments of the present invention include the following, the present invention is not limited to the following embodiments.

<Section 1>
A polybutylene terephthalate resin composite comprising polybutylene terephthalate resin composition pellets and an external additive,
The polybutylene terephthalate resin composition pellets include a polybutylene terephthalate resin having a terminal carboxyl group content of 30 meq/kg or less, and a carbodiimide compound in an amount of 0.1 to 1.0% by mass of the total mass of the polybutylene terephthalate resin composite. including;
The external additive is a polybutylene terephthalate resin composite containing 0.005 to 0.10% by mass of a fatty acid metal salt having a number average particle diameter of 20 μm or less based on the total mass of the polybutylene terephthalate resin composite.
<Section 2>
Item 2. The polybutylene terephthalate resin composite according to item 1, wherein the external additive further contains at least one selected from the group consisting of polyethylene glycol, liquid paraffin, paraffin wax, water, and glycerin.
<Section 3>
Item 3. The polybutylene terephthalate resin composite according to item 1 or 2, wherein the polybutylene terephthalate resin composition pellets have a diameter of 2.0 to 3.0 mm and a length of 1.0 to 3.5 mm.
<Section 4>
4. The polybutylene terephthalate resin composite according to any one of Items 1 to 3, wherein the fatty acid metal salt contains calcium stearate.
<Section 5>
Item 5. The method for producing a polybutylene terephthalate resin composite according to any one of Items 1 to 4, which comprises mixing the polybutylene terephthalate resin composition pellets and the external additive.

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to the following Examples.

<Examples 1 to 4 and Comparative Examples 1 to 6>
In each Example and Comparative Example, component (A) (polybutylene terephthalate resin) and component (B) (carbodiimide compound) shown in Tables 1 and 2 below were used in the ratios (% by mass) shown in Tables 1 and 2 below, Using a twin-screw extruder (TEX30 manufactured by Japan Steel Works, Ltd.) with a 30 mmφ screw, the mixture was melt-kneaded and extruded at a cylinder temperature of 260°C and a screw rotation speed of 130 rpm, and pelletized with a strand cutter to obtain a product with a diameter of 2.3 mm and a length of 2.3 mm. Polybutylene terephthalate resin composition pellets with a diameter of 3.0 mm were obtained.

Regarding Examples 1 to 4 and Comparative Examples 3 to 5, the pellets obtained as described above were put into a tumbler type mixer, and then component (D) (sticking agent) shown in Tables 1 and 2 below was added to the pellets as shown below. The ratios (mass%) shown in Tables 1 and 2 were added to a tumbler mixer, mixed for 10 minutes, and the component (C) (fatty acid metal salt) shown in Tables 1 and 2 below was added to the ratio (mass%) shown in the tables below. % by mass) into a tumbler mixer and mixed for 10 minutes.
In this way, polybutylene terephthalate resin composites of Examples 1 to 4 and Comparative Examples 3 to 5 were obtained.
In Comparative Example 1, component (C) and component (D) were not added, and the pellets of Comparative Example 1 obtained above were used as they were for subsequent evaluation.
In Comparative Example 2, the pellets of Comparative Example 2 obtained as described above were put into a tumbler mixer, and then the component (D) (sticking agent) shown in Table 2 below was added in the ratio ( parts by mass) and mixed for 10 minutes to obtain a polybutylene terephthalate resin composite of Comparative Example 2.

Details of each component shown in Tables 1 and 2 are as follows. The unit of content of each component in Tables 1 and 2 is mass %.

(A) Polybutylene terephthalate resin A1: Polybutylene terephthalate resin (intrinsic viscosity (IV) = 1.14 dL/g, terminal carboxyl group amount = 7 meq/kg, manufactured by Polyplastics Co., Ltd.)
A2: Polybutylene terephthalate resin (intrinsic viscosity (IV) = 0.83 dL/g, terminal carboxyl group amount = 15 meq/kg, manufactured by Polyplastics Co., Ltd.)

(B) Carbodiimide compound B1: Aromatic polycarbodiimide (Stabaxol P-100, manufactured by Lanxess)

(C): Fatty acid metal salt C1: Calcium stearate (number average particle diameter 15 μm, manufactured by NOF Corporation)
C2: Calcium stearate (number average particle diameter 24 μm, manufactured by NOF Corporation)
C3: Calcium stearate (number average particle diameter: 180 μm, manufactured by Nitto Kasei Kogyo Co., Ltd.)

(D): Adhesive agent D1: Polyethylene glycol (CLE-400 manufactured by ADEKA Co., Ltd.)

The number average particle diameter of the fatty acid metal salt of component (C) is the number average particle diameter calculated by measuring the particle size distribution using a laser diffraction scattering particle size distribution analyzer, and was determined as follows. Put a trace amount (approximately 10 to 20 mg) of fatty acid metal salt with a medicine spoon into a 10 mL vial, add 10 mL of acetone, and thoroughly disperse with an ultrasonic cleaner. The particle size distribution was measured using a measuring device LA-960, and the number average particle size was calculated.

<Evaluation>
The following evaluations were performed using the polybutylene terephthalate resin composites of Examples 1 to 4 and Comparative Examples 2 to 5, and the pellets of Comparative Example 1. The results are shown in Tables 1 and 2.

(1) Metrology The polybutylene terephthalate resin composites of Examples 1 to 4 and Comparative Examples 2 to 5 obtained above, and the pellets of Comparative Example 1 were each dried at 140°C for 3 hours and then injection-molded. Using an injection molding machine S2000i 100B manufactured by FANUC Co., Ltd. as a molding machine and an ISO multi-purpose test piece (two-cavity) shaped mold as a mold, continuous molding was performed under the following molding conditions, and the measuring time and The amount of cushioning was monitored and judged based on the following criteria.

(Molding condition)
Cylinder temperature: (nozzle) 260-260-260-240℃ (hopper)
Injection speed: 23mm/sec Mold temperature: 80℃
Holding pressure: 50MPa
Holding pressure time: 25 seconds Measurement value: 65mm
Suck back: 3mm
V-P position: 17mm
Cooling time: 25 seconds Back pressure: 5MPa
Rotation speed: 50rpm
Number of shots: 20 shots

(Metricability judgment criteria)
A: For all 20 shots, measurement is completed within the set cooling time (25 seconds), allowing continuous molding. B: For some of the 20 shots, measurement is not completed within the set cooling time (25 seconds). However, for all 20 shots, the measurement is completed within the set cooling time (25 seconds), or the measurement is not completed within the set cooling time (25 seconds) but the set cooling time (25 seconds) Measurement is completed within +10 seconds and continuous molding is possible C: Measurement may not be completed within the set cooling time (25 seconds) +10 seconds and continuous molding is not possible.

(2) Powder removal property A case in which no calcium stearate powder was observed in the hopper during the above injection molding, and a case B in which calcium stearate powder was observed.

(3) Hydrolysis resistance After drying the polybutylene terephthalate resin composites of Examples 1 to 4 and Comparative Examples 2 to 5 and the pellets of Comparative Example 1 obtained above at 140°C for 3 hours, A 1A type tensile test piece conforming to ISO3167 was prepared by injection molding at a cylinder temperature of 260°C and a mold temperature of 80°C. Regarding the obtained test piece, the tensile nominal strain at break was measured as a tensile property in accordance with ISO527-1, 2. Next, using a PCT processing device (highly accelerated life testing device), the test piece was exposed to moist heat conditions of 121°C and 100% RH for 50 hours, and the nominal tensile strain at break was measured after 50 hours of exposure to moist heat conditions. .

As shown in Table 1, in Examples 1 to 4, it was shown that the measurement time was short and the measurement performance was excellent. Further, in Examples 1 to 4, the decrease in the nominal tensile strain at break after 50 hours of exposure to moist heat conditions from the initial value (nominal tensile strain at failure before exposure to moist heat conditions) was small, and the hydrolysis resistance was also good.

On the other hand, Comparative Examples 1 and 2 in which no fatty acid metal salt was used had poor measurement stability. In Comparative Examples 3 to 5, in which fatty acid metal salts with excessive average particle diameters were used, the nominal tensile strain at break after 50 hours of exposure to moist heat conditions decreased from the initial value (nominal tensile strain at failure before exposure to moist heat conditions). was large, and the hydrolysis resistance was poor. Comparative Example 6, in which the amount of fatty acid metal salt was excessive, had a small initial value of nominal tensile strain at fracture, indicating poor toughness.

Claims (5)

A polybutylene terephthalate resin composite comprising polybutylene terephthalate resin composition pellets and an external additive,
The polybutylene terephthalate resin composition pellets include a polybutylene terephthalate resin having a terminal carboxyl group content of 30 meq/kg or less, and a carbodiimide compound in an amount of 0.1 to 1.0% by mass of the total mass of the polybutylene terephthalate resin composite. including;
The external additive is a polybutylene terephthalate resin composite containing a fatty acid metal salt having a number average particle diameter of 20 μm or less and 0.005 to 0.10% by mass of the total mass of the polybutylene terephthalate resin composite. The polybutylene terephthalate resin composite according to claim 1, wherein the external additive further contains at least one selected from the group consisting of polyethylene glycol, liquid paraffin, paraffin wax, water, and glycerin. The polybutylene terephthalate resin composite according to claim 1 or 2, wherein the polybutylene terephthalate resin composition pellet has a diameter of 2.0 to 3.0 mm and a length of 1.0 to 3.5 mm. The polybutylene terephthalate resin composite according to claim 1 or 2, wherein the fatty acid metal salt contains calcium stearate. The method for producing a polybutylene terephthalate resin composite according to claim 1 or 2, comprising mixing the polybutylene terephthalate resin composition pellets and the external additive.