JP7111499B2 - Polybutylene terephthalate resin composition molded article - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polybutylene terephthalate resin composition molded article, and more particularly to a polybutylene terephthalate resin composition molded article having low warpage, low specific gravity, low gas generation, and excellent mechanical properties at high temperatures.

Polybutylene terephthalate resin has excellent mechanical and electrical properties, as well as excellent chemical resistance and heat resistance. It is widely used as a material for manufacturing interior parts for vehicles such as , and other general industrial products.

However, since the polybutylene terephthalate resin is a crystalline resin, in the injection molding of the resin, shrinkage due to crystallization of the resin occurs during the process of cooling and solidifying in the mold, and molding shrinkage is likely to occur. Since the degree of molding shrinkage differs from part to part of the molded product, the molded product is warped.

In order to suppress molding shrinkage, it is known to blend an amorphous resin in order to suppress molecular orientation due to crystallization of polybutylene terephthalate resin, and acrylonitrile-styrene copolymer is used as the amorphous resin. It has been proposed to use it (see Patent Documents 1 to 3).

JP-A-09-12849 JP-A-2006-16558 WO2016/190311

However, even with these inventions, it is by no means easy to achieve a sufficiently low warpage property.
Furthermore, when polybutylene terephthalate resin materials are used in the interior of automobiles, there are strict guidelines for the emission of TVOC (total volatile organic compounds) emissions, which must be cleared for vehicle interior parts. is strongly demanded.
An object (subject) of the present invention is to provide a polybutylene terephthalate resin composition molded article which has low warpage, low specific gravity, little gas generation, and excellent mechanical properties at high temperatures.

As a result of intensive studies to solve the above problems, the present inventors have found that the polybutylene terephthalate resin contains a specific amount of an acrylonitrile-styrene copolymer, and the domain of the acrylonitrile-styrene copolymer The present inventors have found that a polybutylene terephthalate resin composition molded article having a morphology of a sea-island structure in which is dispersed as islands in a specific shape and having a specific amount of TVOC can solve the above-described problems, and have arrived at the present invention.
The present invention relates to the following polybutylene terephthalate resin composition molded article.

[1] Acrylonitrile-styrene copolymer (B1) and/or epoxy-modified acrylonitrile-styrene copolymer as styrene copolymer (B) for 100 parts by mass of polybutylene terephthalate resin (A) A molded article having a sea-island structure and a minimum thickness of more than 1 mm, comprising a polybutylene terephthalate resin composition containing a total of 45 to 100 parts by mass of (B2),
Polybutylene terephthalate resin (A) forms a continuous phase,
Domains containing the styrenic copolymer (B) are dispersed in the form of islands in the continuous phase of the polybutylene terephthalate resin (A), and at least a portion of the domains are contained in the island-shaped portions of the polybutylene terephthalate resin ( The phase A) exists as a lake and has a morphology in which the maximum width of the island-shaped portion measured by the following method is 6 μm or less,
The amount of volatile organic compounds (TVOC) detected when the gas generated by heat-treating the molded body at 120 ° C. for 5 hours is analyzed by gas chromatography is 30 μg C / g or less.
A polybutylene terephthalate resin composition molded article characterized by:
How to measure the maximum width of the island:
The maximum value of the width of the island-like portion is measured from the SEM image (magnification: 3000) of the cross section including the central point in the thickness direction of the portion where the thickness of the molded body is the maximum.
[2] The polybutylene terephthalate resin composition molded article according to [1] above, wherein at least a part of the island-shaped portion of the polybutylene terephthalate resin (A) is an island-shaped portion having a branched portion.
[3] The polybutylene terephthalate resin composition molded article according to the above [1] or [2], wherein the amount of TVOC from the molded article is 20 μgC/g or less.
[4] The above [1], wherein the amount of the styrene-based monomer detected when the gas generated by heat-treating the polybutylene terephthalate resin composition at 270°C for 10 minutes is analyzed by gas chromatography is 45 ppm by mass or less. ] to the polybutylene terephthalate resin composition molded article according to any one of [3].
[5] The polybutylene terephthalate resin composition molded article according to any one of [1] to [4] above, wherein the polybutylene terephthalate resin composition further contains an epoxy-modified acrylic polymer (C).
[6] The polybutylene terephthalate resin composition comprises 45 to 100 parts by mass of acrylonitrile-styrene copolymer (B1) and epoxy-modified acrylic polymer (C) per 100 parts by mass of polybutylene terephthalate resin (A). The polybutylene terephthalate resin composition molded article according to any one of [1] to [5] above, containing 0.2 to 3 parts by mass and 10 to 100 parts by mass of the glass fiber (D).
[7] The polybutylene terephthalate resin composition is a total of acrylonitrile-styrene copolymer (B1) and epoxy-modified acrylonitrile-styrene copolymer (B2) with respect to 100 parts by mass of polybutylene terephthalate resin (A). 45 to 100 parts by mass, the mass ratio (B)/(B2) of the contents of (B) and (B2) is 6 or less, and the glass fiber (D) is 10 to 100 parts by mass. The polybutylene terephthalate resin composition molded article according to any one of [1] to [4].
[8] The molded article according to any one of [1] to [7], which is a vehicle interior part.

The polybutylene terephthalate resin composition molded article of the present invention has less warpage, less gas generation, can clear VOC regulations, has a low specific gravity, and mechanical properties such as mechanical strength in an environment assuming high temperatures inside a car. , it can be suitably used as a vehicle interior part.

1 is a SEM image of the molded article of Example 1, taken with a scanning electron microscope. 4 is a scanning electron microscope SEM image of the molded article of Example 2. FIG. 4 is a SEM image of the molded article of Example 3, taken with a scanning electron microscope. 10 is a SEM image of the molded article of Example 4 by a scanning electron microscope. FIG. 10 is a SEM image of the molded article of Example 7 by a scanning electron microscope; FIG. FIG. 10 is a SEM image of the molded article of Example 9 by a scanning electron microscope; FIG. FIG. 10 is a SEM image of the molded article of Example 11 by a scanning electron microscope; FIG. 4 is a scanning electron microscope SEM image of the compact of Comparative Example 1. FIG. 4 is a SEM image of the compact of Comparative Example 2, taken with a scanning electron microscope. 10 is a SEM image of the compact of Comparative Example 4, taken with a scanning electron microscope. FIG. 4 is a schematic diagram showing the width of the island-shaped portions of the sea-island structure of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. Although the explanations described below may be made based on embodiments and specific examples, the present invention should not be construed as being limited to such embodiments and specific examples.
In this specification, the term "~" is used to mean that the numerical values before and after it are included as the lower limit and the upper limit.

In the polybutylene terephthalate resin composition molded article of the present invention, acrylonitrile-styrene copolymer (B1) and/or epoxy A molded article having a sea-island structure and a minimum thickness of more than 1 mm, comprising a polybutylene terephthalate resin composition containing a total of 45 to 100 parts by mass of a modified acrylonitrile-styrene copolymer (B2). ,
Polybutylene terephthalate resin (A) forms a continuous phase,
Domains containing the styrenic copolymer (B) are dispersed in the form of islands in the continuous phase of the polybutylene terephthalate resin (A), and at least a portion of the domains are contained in the island-shaped portions of the polybutylene terephthalate resin ( The phase A) exists as a lake and has a morphology in which the maximum width of the island-shaped portion measured by the following method is 6 μm or less,
The amount of volatile organic compounds (TVOC) detected when the gas generated by heat-treating the compact at 120° C. for 5 hours is analyzed with a gas chromatograph is 30 μgC/g or less.
How to measure the maximum width of the island:
The maximum value of the width of the island-like portion is measured from the SEM image (magnification: 3000) of the cross section including the central point in the thickness direction of the portion where the thickness of the molded body is the maximum.

The molded article of the present invention has a minimum thickness of more than 1 mm, preferably 1.2 mm or more, more preferably 1.5 mm or more, still more preferably 1.8 mm or more, particularly 2.0 mm or more. Preferably. Although the maximum thickness of the molded body is not limited, it is preferably 10.0 mm or less, more preferably 8.0 mm or less, and still more preferably 6.0 mm or less.

[Morphology]
Observation of the molded body morphology with a scanning electron microscope is carried out using a SEM image of the thickest part (maximum thickness part) of the molded body and a cross section including the central point in the thickness direction, obtained with a scanning electron microscope. .
That is, first, the molded body is cut in the thickness direction at the maximum thickness portion. At this time, the injection gate portion during molding is excluded from the maximum thickness portion of the molded body. In addition, when there are multiple maximum thickness parts in the molded body, the length between the injection gate part and the flow terminal part of the resin is measured from any one arbitrary place in the case of a molded body with uniform thickness. Cut near the middle of the direction.
A sample for SEM observation of a cross section including the center point in the thickness direction of the cut surface is cut from the cut surface with a diamond knife to obtain a block-shaped sample with an observation surface of 500 μm long×500 μm wide and about 1 cm thick. After staining the observed surface of the obtained sample with ruthenium tetroxide, a scanning electron microscope is used to acquire an SEM image under the condition of an acceleration voltage of 1 kV.
The SEM image used for observation has a field of view with a magnification of 3000 times, and when there is glass fiber in the resin composition in the field of view, an image is selected in which the cross-sectional area of the glass fiber is 10% or less of the field of view area.
Details of a specific analysis method are as described in detail in Examples.

FIGS. 1 to 7 are SEM images (magnification: 3000) taken by a scanning electron microscope of the molded bodies obtained in the examples of the present application.
In the figure, the black gray portion (the portion with the lowest brightness) is the phase of the polybutylene terephthalate resin (A), forming the sea as a continuous phase. In the figure, the light gray part (the part with higher brightness than the polybutylene terephthalate resin phase) is the domain containing the styrene copolymer (B), and is an island in the continuous sea of the polybutylene terephthalate resin (A). In addition, the polybutylene terephthalate resin (A) phase exists as a lake (pond) within the islands in the island-shaped portions of the styrene copolymer (B). The width of the island portion is not excessively large, and the maximum width is 6 μm or less. In the figure, a large circular or semicircular portion having a color tone between the lowest lightness portion and the light gray portion is glass fiber.

On the other hand, FIGS. 8 and 9 are SEM images (magnification: 3000) taken by a scanning electron microscope of the compact obtained in Comparative Example of the present application. 9 (Comparative Example 2) is very large. Further, in FIG. 10 of Comparative Example 4 of the present application, the islands containing the styrene copolymer (B) are uniformly and finely dispersed in the continuous phase of the polybutylene terephthalate resin (A), and It can be seen that the presence of a lake (pond) of polybutylene terephthalate resin (A) is not observed in the sample.

FIG. 11 is a schematic diagram for explaining the sea-island structure of the present invention. In the figure, 1 is an island-like portion, which exists in the continuous phase (sea) of the black-grey polybutylene terephthalate resin (A) phase. Polybutylene terephthalate resin (A) exists as a lake 2 as indicated by 2 in the figure in the island-shaped portion 1 of the styrene copolymer (B). In the present invention, the island-like portion 1 preferably has a shape having a branch portion 3 as indicated by 3 in FIG. It is also preferred that the plurality of branches 3 are connected to each other.

As described above, in the island-shaped portion 1, the phase of the polybutylene terephthalate resin (A) exists as a lake (pond) 2 in the island, and the maximum value of the width d of the island-shaped portion 1 is 6 μm. It is below.
The width d of the island-shaped portion is defined as the width length d perpendicular to the width center line L of the island-shaped portion, as indicated by the dashed line in FIG. The width center line L of the island-shaped portion is the width center line L', L '', and the width d of the island-like portion is the width d orthogonal to these L' and L''.

The maximum value of the width d of the island-shaped portion is 6 μm or less, preferably 5 μm or less, more preferably 4 μm or less, and preferably 2 μm or more, more preferably 3 μm or more.
When the maximum value of the width d of the island-shaped portion exceeds 6 μm, the mechanical strength (particularly bending strength and tensile strength retention) at high temperatures, which is a feature of the sea-island structure of the present invention, deteriorates.

In addition, when only the island-shaped portions without the lake of the polybutylene terephthalate resin (A) are present in the island-shaped portions, the warp of the molded article, which is a feature of the sea-island structure of the present invention, becomes worse.
In the present invention, the ratio of the presence of the island-shaped portions where the lakes of the polybutylene terephthalate resin (A) are present is defined as [the area of all the island-shaped portions (however, this area includes the area of the lakes The ratio (%) of the [total area of the islands where the phase (A) exists as a lake (however, this area does not include the area of the lake)] to the total of Specifically, it is preferably 10% or more, more preferably 20% or more, still more preferably 25% or more, especially 30% or more, particularly preferably 40% or more, particularly preferably 60% or more.
Here, the “island-shaped portion having a lake” is defined as an island-shaped portion having a lake with a major axis of 1 μm or more in the field of view of the SEM image (magnification: 3000).

[TOVC amount]
Further, the amount of volatile organic compounds (TVOC amount) of the polybutylene terephthalate resin composition molded article of the present invention is characterized by being 30 μgC/g or less.
A specific method for measuring the amount of volatile organic compounds (TVOC) of the polybutylene terephthalate resin composition molded article is as described in detail in Examples.

The molded article of the present invention is essentially made of a composition containing at least a predetermined amount of a polybutylene terephthalate resin (A) and a styrene copolymer (B).
Each component constituting the polybutylene terephthalate resin composition used for the resin composition molded article of the present invention will be described below.

[Polybutylene terephthalate resin (A)]
The polybutylene terephthalate resin (A) used in the polybutylene terephthalate resin composition is a polyester resin having a structure in which terephthalic acid units and 1,4-butanediol units are ester-bonded, and is a polybutylene terephthalate resin (homopolymer). Other examples include polybutylene terephthalate copolymers containing copolymer components other than terephthalic acid units and 1,4-butanediol units, and mixtures of homopolymers and such copolymers.

The polybutylene terephthalate resin (A) may contain dicarboxylic acid units other than terephthalic acid, and specific examples of other dicarboxylic acids include isophthalic acid, orthophthalic acid, 1,5-naphthalene dicarboxylic acid, 2,5 -naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-2,2'-dicarboxylic acid, biphenyl-3,3'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, bis(4,4'- carboxyphenyl)methane, anthracenedicarboxylic acid, 4,4′-diphenylether dicarboxylic acid and other aromatic dicarboxylic acids; 1,4-cyclohexanedicarboxylic acid, 4,4′-dicyclohexyldicarboxylic acid and other alicyclic dicarboxylic acids; and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid and dimer acid.

The diol unit may contain other diol units in addition to 1,4-butanediol, and specific examples of other diol units include aliphatic or alicyclic diols having 2 to 20 carbon atoms. , bisphenol derivatives and the like. Specific examples include ethylene glycol, propylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, decamethylene glycol, cyclohexanedimethanol, 4,4′-dicyclohexylhydroxymethane, ,4'-dicyclohexylhydroxypropane, ethylene oxide-added diol of bisphenol A, and the like. In addition to the above bifunctional monomers, trifunctional monomers such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, and trimethylolpropane for introducing a branched structure, and fatty acids for molecular weight adjustment. A small amount of monofunctional compound can also be used together.

As described above, the polybutylene terephthalate resin (A) is preferably a polybutylene terephthalate homopolymer obtained by polycondensation of terephthalic acid and 1,4-butanediol. A polybutylene terephthalate copolymer containing one or more diols other than the 1,4-butanediol may be used as one or more dicarboxylic acid and/or diol units of the polybutylene terephthalate resin (A). In the case of a polybutylene terephthalate resin modified by polymerization, specific preferred copolymers thereof include polyester ether resins obtained by copolymerizing polyalkylene glycols, particularly polytetramethylene glycol, and polybutylene terephthalate copolymerized with dimer acid. resins, and isophthalic acid-copolymerized polybutylene terephthalate resins. Among them, it is preferable to use a polyester ether resin obtained by copolymerizing polytetramethylene glycol. In addition, these copolymers refer to those having a copolymerization amount of 1 mol % or more and less than 50 mol % in all segments of the polybutylene terephthalate resin. Among them, the copolymerization amount is preferably 2 mol % or more and less than 50 mol %, more preferably 3 to 40 mol %, particularly preferably 5 to 20 mol %. By setting such a copolymerization ratio, fluidity, toughness, and tracking resistance tend to be improved, which is preferable.

The terminal carboxyl group content of the polybutylene terephthalate resin (A) may be appropriately selected and determined, but is usually 60 eq/ton or less, preferably 50 eq/ton or less, and 30 eq/ton or less. is more preferred. If it exceeds 50 eq/ton, gas tends to be generated during melt molding of the resin composition. Although the lower limit of the amount of terminal carboxyl groups is not particularly defined, it is usually 10 eq/ton in consideration of productivity in the production of polybutylene terephthalate resin.

The terminal carboxyl group content of the polybutylene terephthalate resin is a value measured by dissolving 0.5 g of the polyalkylene terephthalate resin in 25 mL of benzyl alcohol and titrating with a 0.01 mol/l benzyl alcohol solution of sodium hydroxide. be. As a method for adjusting the amount of terminal carboxyl groups, any conventionally known method may be used, such as a method of adjusting polymerization conditions such as the raw material charge ratio during polymerization, the polymerization temperature, and a decompression method, or a method of reacting a terminal blocking agent. You can do it.

The polybutylene terephthalate resin (A) preferably has an intrinsic viscosity of 0.5 to 2 dl/g. From the standpoint of moldability and mechanical properties, those having an intrinsic viscosity in the range of 0.6 to 1.5 dl/g are more preferred. If one with an intrinsic viscosity lower than 0.5 dl/g is used, the resulting resin composition tends to have low mechanical strength. On the other hand, if it is higher than 2 dl/g, the flowability of the resin composition may deteriorate and the moldability may deteriorate.
The intrinsic viscosity of the polybutylene terephthalate resin (A) is a value measured at 30° C. in a mixed solvent of tetrachloroethane and phenol at a ratio of 1:1 (mass ratio).

The polybutylene terephthalate resin (A) is obtained by melt-polymerizing a dicarboxylic acid component or ester derivative thereof containing terephthalic acid as a main component and a diol component containing 1,4-butanediol as a main component in a batch or continuous manner. can be manufactured by Further, after producing a low-molecular-weight polybutylene terephthalate resin by melt polymerization, the degree of polymerization (or molecular weight) can be increased to a desired value by solid-phase polymerization under a nitrogen stream or under reduced pressure.
The polybutylene terephthalate resin (A) is obtained by a production method in which a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing 1,4-butanediol as a main component are continuously subjected to melt polycondensation. is preferred.

Catalysts used in carrying out the esterification reaction may be those conventionally known, and examples thereof include titanium compounds, tin compounds, magnesium compounds, calcium compounds, and the like. Particularly suitable among these are titanium compounds. Specific examples of the titanium compound as the esterification catalyst include titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate and tetrabutyl titanate, and titanium phenolates such as tetraphenyl titanate.

[Styrene-based copolymer (B)]
The styrene copolymer (B) used in the polybutylene terephthalate resin composition is acrylonitrile-styrene copolymer (B1) and/or epoxy-modified acrylonitrile-styrene copolymer (B2).

<Acrylonitrile-styrene copolymer (B1)>
The acrylonitrile-styrene copolymer (B1) is a copolymer of acrylonitrile and a styrene monomer, and may be a copolymer obtained by copolymerizing other copolymerizable monomers. Acrylonitrile-styrene-based monomers constituting the styrene-based copolymer (B1) include styrene, α-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinyl Examples include naphthalene, methoxystyrene, monobromostyrene, dibromostyrene, fluorostyrene, and tribromostyrene, with styrene and α-methylstyrene being more preferred, and styrene being particularly preferred.

Other copolymerizable monomers other than styrene-based monomers and acrylonitrile include (meth)acrylic acid ester-based monomers and maleimide-based monomers such as maleimide, N-methylmaleimide, and N-phenylmaleimide. α,β-unsaturated carboxylic acids and their anhydrides such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, phthalic acid, and itaconic acid; epoxy group-containing compounds such as glycidyl (meth)acrylate; Polymerizable unsaturated compounds are excluded.
Among these, (meth)acrylic acid ester-based monomers are preferred, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, phenyl (meth)acrylate, Benzyl (meth)acrylate and the like can be mentioned, and in particular methyl methacrylate can be mentioned.
The notation of (meth)acrylate indicates that both methacrylate and acrylate are included, and the notation of (meth)acrylic acid ester indicates that both methacrylic acid ester and acrylic acid ester are included.

Acrylonitrile-styrene copolymer (B1) is preferably acrylonitrile-styrene copolymer (AS resin), acrylonitrile-styrene-acrylic rubber copolymer (ASA resin), especially acrylonitrile-styrene copolymer (AS resin) is preferred.

The acrylonitrile-styrene copolymer (B1) preferably contains units derived from acrylonitrile monomers in an amount of 5 to 50% by mass, more preferably 8 to 35% by mass. Also, the content of units derived from styrene-based monomers is preferably 50 to 95% by mass, more preferably 65 to 92% by mass.
In the present invention, the acrylonitrile amount in the acrylonitrile-styrene copolymer (B1) is measured by the Kjeldahl method.

The melt volume rate (MVR) of the acrylonitrile-styrene copolymer (B1) is preferably in the range of 5 to 100 cm ³ /10 minutes at 220° C. and a load of 10 kg, more preferably 10 to 80 cm ³ /10 minutes. is more preferred.
The mass average molecular weight (Mw) of the acrylonitrile-styrene copolymer (B1) is preferably in the range of 60,000 to 220,000, more preferably 80,000 to 200,000.
In the present invention, the mass average molecular weight (Mw) of the acrylonitrile-styrene copolymer (B1) is measured by GPC (gel permeation chromatography).

The method for producing the acrylonitrile-styrene copolymer (B1) is not limited and a known method can be employed. For example, methods such as bulk polymerization, emulsion polymerization, solution polymerization and suspension polymerization are used. Among them, bulk polymerization is preferred because it does not use a solvent or an emulsifier and therefore contains few impurities.
Acrylonitrile-styrene copolymer (B1) is commercially available, and bulk polymerization products, emulsion polymerization products, solution polymerization products, suspension polymerization products, etc. are commercially available. Since no emulsifier is used, the polybutylene terephthalate resin composition of the present invention produces less impurities and less gas is generated.

<Epoxy-modified acrylonitrile-styrene copolymer (B2)>
The epoxy-modified acrylonitrile-styrene-based copolymer (B2) is not particularly limited, but is preferably a copolymer of an unsaturated glycidyl compound, acrylonitrile and a styrene-based monomer, and other copolymerizable monomers. may be a copolymer obtained by copolymerizing the

Styrene-based monomers constituting the epoxy-modified acrylonitrile-styrene-based copolymer (B2) include styrene, α-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, and p-tert-butylstyrene. , vinylnaphthalene, methoxystyrene, monobromostyrene, dibromostyrene, fluorostyrene, and tribromostyrene, with styrene and α-methylstyrene being more preferred, and styrene being particularly preferred.

As the unsaturated glycidyl compound constituting the epoxy-modified acrylonitrile-styrene copolymer (B2), epoxy group-containing polymerizable unsaturated compounds are preferable, and unsaturated glycidyl esters such as glycidyl (meth)acrylate and glycidyl itaconate. Alternatively, unsaturated glycidyl ethers such as vinyl glycidyl ether, allyl glycidyl ether, 2-methylallyl glycidyl ether, styrene-p-glycidyl ether and the like are preferred. Among them, unsaturated glycidyl esters, particularly epoxy group-containing (meth)acrylic acid esters are preferred, more preferably glycidyl (meth)acrylate, that is, glycidyl acrylate and glycidyl methacrylate (GMA), particularly glycidyl methacrylate (GMA). preferable.

In addition, the epoxy-modified acrylonitrile-styrene copolymer (B2) may be copolymerized with other monomers other than the above. It can be contained in an amount of less than 50% by weight, preferably less than 30% by weight, more preferably less than 10% by weight of the total coalescence (B2).

The epoxy-modified acrylonitrile-styrene copolymer (B2) is preferably a glycidyl methacrylate (GMA)-modified acrylonitrile-styrene copolymer.

The epoxy equivalent of the epoxy-modified acrylonitrile-styrene copolymer (B2) is preferably 2000-30000 g/mol, more preferably 4000-28000 g/mol. If the epoxy equivalent exceeds 30,000 g/mol, the epoxy-modified acrylonitrile-styrene copolymer may not be sufficiently dispersed in the composition. may be damaged.

The content of units derived from an acrylonitrile compound in the epoxy-modified acrylonitrile-styrene copolymer (B2) is usually 2 to 50% by mass, preferably 20 to 30% by mass, based on 100% by mass of the entire polymer (B2). The content of units derived from styrene-based monomers is usually 50 to 98% by mass, preferably 70 to 80% by mass, and the content of units derived from unsaturated glycidyl compounds is usually 0.1 to 1.0% by mass. %, preferably 0.2 to 0.8 mass %. In the present invention, the amount of acrylonitrile in the epoxy-modified acrylonitrile-styrene copolymer (B2) is measured by the Kjeldahl method. In addition, measurement of unsaturated glycidyl compounds is carried out according to JIS K7236.

The epoxy-modified acrylonitrile-styrene copolymer (B2) preferably has an MVR of 5 to 100 cm ³ /10 min at 220° C. and a load of 10 kg, and a weight average molecular weight (Mw) of preferably 60,000 to 220,000. Yes, more preferably 70,000 to 200,000. Measurement of the weight average molecular weight (Mw) is performed by the GPC (gel permeation chromatography) method.

The method for producing the epoxy-modified acrylonitrile-styrene copolymer (B2) is not limited and any known method can be employed. For example, methods such as bulk polymerization, emulsion polymerization, solution polymerization and suspension polymerization are used. Among these, bulk polymerization is preferred because it does not use a solvent or an emulsifier and therefore contains few impurities.
The epoxy-modified acrylonitrile-styrene copolymer (B2) is commercially available, and bulk polymerized products, emulsion polymerized products, solution polymerized products, suspension polymerized products, etc. are commercially available. is preferable because it does not use a solvent or an emulsifier and therefore contains few impurities.

In the present invention, the styrenic copolymer (B) is heat-treated at 270° C. for 10 minutes and the gas generated is analyzed with a gas chromatograph to measure the amount of the styrenic monomer and the amount of ethylbenzene. However, it is preferable to use one in which the amount of the styrene-based monomer is 600 (mass) ppm or less. When the amount of styrene-based monomer gas is 600 ppm or less, the amount of gas generated during molding is reduced, and the amount of gas generated from the molded product is small. Therefore, the problem of VOC when used as vehicle interior parts, for example, is solved. Also, since less gas is produced during molding, the appearance of the molded product is improved. On the other hand, if it exceeds 600 ppm, it becomes difficult to solve the VOC problem when used as interior parts for vehicles, and the appearance tends to be poor. The amount of styrenic monomer is more preferably 550 ppm or less, still more preferably 300 ppm or less, particularly preferably 200 ppm or less, and the lower limit is usually 50 ppm. When the acrylonitrile-styrene copolymer (B1) and/or the epoxy-modified acrylonitrile-styrene copolymer (B2) are used together as the styrene copolymer (B), each polymer is the total amount calculated from the amount of styrene-based monomer gas and the mass ratio of each to be used, and the total calculated in the same manner from (B1) and / or (B2) when using multiple types means the amount of
The amount of styrene in the starting styrene copolymer (B) or the starting polybutylene terephthalate resin composition was obtained by analyzing the gas generated by heat treatment at 270°C for 10 minutes with a gas chromatograph. It is an amount (unit: mass ppm) converted into a value per amount of copolymer or resin composition. Details of the specific measurement method are as described in Examples.

In addition, the total amount of styrene monomer and ethylbenzene when analyzing the gas generated by heat-treating the starting styrene copolymer (B) at 270° C. for 10 minutes with a gas chromatograph is 650 (mass) ppm or less. is preferred. When the total gas amount of both is 650 ppm or less, the amount of gas generated during molding is reduced, and the amount of gas generated from the molded product when formed into a molded product is small. The problem of VOC is solved, and the appearance of the molded product is improved because less gas is used during molding. The total gas amount of both is more preferably 500 ppm or less, more preferably 400 ppm or less, and the lower limit is usually 150 ppm. In order to reduce the concentration to less than 150 ppm, it is not preferable because it requires purification that disregards economic efficiency.
As the styrene copolymer (B), when the acrylonitrile-styrene copolymer (B1) and/or the epoxy-modified acrylonitrile-styrene copolymer (B2) are used in combination, It is the total amount calculated from the amount of styrene monomer and ethylbenzene generated from each polymer and the mass ratio of each used, and multiple types are used from (B1) and / or (B2) means the amount of total calculated in the same way.

In order to make the total amount of the styrene monomer in the styrene copolymer (B) and the total amount of the styrene monomer and ethylbenzene within the above range, the configuration of the devolatilization step after the polymerization of the styrene copolymer It is possible by strengthening the operating conditions of the devolatilization process and the devolatilization process. In the case of suspension polymerization, etc., the resulting copolymer latex is stripped at a suitable temperature and vacuum, or coagulated with hot steam, or stripped at reduced pressure with hot steam. or washing the solidified copolymer with hot water and drying it under vacuum. Bulk polymerization is also possible by adjusting the degree of vacuum, supply rate or heating temperature in the vacuum devolatilization device.
It is also possible to select a commercially available product that satisfies the conditions, or to further dry the commercially available product to obtain the desired amounts of styrene-based monomers and ethylbenzene.

The total content of acrylonitrile-styrene copolymer (B1) and/or epoxy-modified acrylonitrile-styrene copolymer (B2), that is, the content of styrene copolymer (B) is polybutylene terephthalate resin (A ) is 45 to 100 parts by mass with respect to 100 parts by mass. If the content is less than 45 parts by mass, the ratio of the amorphous resin is low and the shrinkage rate increases, resulting in warping of the molded product. In addition to the decrease, the bending strength at 85° C. atmosphere and the weld strength also decrease. The content of the styrenic copolymer (B) is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, still more preferably 60 parts by mass or more, particularly preferably more than 65 parts by mass, preferably 95 parts by mass or more. It is not more than 90 parts by mass, more preferably not more than 90 parts by mass.

[Epoxy-modified acrylic polymer (C)]
The polybutylene terephthalate resin composition preferably further contains an epoxy-modified acrylic polymer (C). Although the epoxy-modified acrylic polymer (C) is not particularly limited, an acrylic polymer composed of a (meth)acrylic acid alkyl ester and an unsaturated glycidyl compound is preferable.

Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, and (meth)acrylic acid. isobutyl, s-butyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, (Meth)acrylic acid alkyl esters having a linear or branched alkyl group such as decyl (meth)acrylate and dodecyl (meth)acrylate are preferred, and among them, (meth)acrylic acid having 1 to 12 carbon atoms is preferred. Alkyl esters are more preferred, and methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate are preferred.
In this specification, "(meth)acryl" means "acryl" and/or "methacryl".

As the unsaturated glycidyl compound, epoxy group-containing polymerizable unsaturated compounds are preferable, and unsaturated glycidyl esters such as glycidyl (meth)acrylate and glycidyl itaconate, or vinyl glycidyl ether, allyl glycidyl ether, 2-methyl Unsaturated glycidyl ethers such as allyl glycidyl ether and styrene-p-glycidyl ether are preferred. Among them, unsaturated glycidyl esters, particularly epoxy group-containing (meth)acrylic acid esters are preferred, more preferably glycidyl (meth)acrylate, that is, glycidyl acrylate and glycidyl methacrylate (GMA), particularly glycidyl methacrylate (GMA). preferable.

Further, the epoxy-modified acrylic polymer (C) is preferably a copolymer obtained by copolymerizing other monomers than the above, and particularly preferably a copolymer obtained by copolymerizing a styrene monomer.
Styrenic monomers include styrene, α-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, monobromostyrene, dibromostyrene, Examples include fluorostyrene and tribromostyrene, with styrene and α-methylstyrene being more preferred, and styrene being particularly preferred.

The epoxy-modified acrylic polymer (C) contains a structural unit derived from a (meth)acrylic acid alkyl ester (C1), an epoxy group-containing (meth)acrylic acid ester (C2), or a styrene monomer (C3). When it is contained, the preferable content of each structural unit is preferably 50 to 99% by mass, more preferably 55 to 95% by mass, when the mass of the epoxy-modified acrylic polymer (C) is 100% by mass. % by mass, the C2 component is preferably 0.05 to 20% by mass, more preferably 0.1 to 18% by mass, and the C3 component is preferably 0 to 49.5% by mass, more preferably 0 to 45% by mass. % by mass, more preferably 5 to 45% by mass.

The epoxy equivalent of the epoxy-modified acrylic polymer (C) is preferably 100-1000 g/mol, more preferably 200-800 g/mol. If the epoxy equivalent exceeds 1000 g/mol, the acrylonitrile-styrene copolymer may not be sufficiently dispersed in the composition, while if it is less than 100 g/mol, the viscosity increases significantly and moldability is impaired. Sometimes.

The weight average molecular weight (Mw) of the epoxy-modified acrylic polymer (C) is preferably 4000-13000, more preferably 5000-12000.

A preferable content of the epoxy-modified acrylic polymer (C) is 0.2 to 3 parts by mass with respect to 100 parts by mass of the polybutylene terephthalate resin (A). If the amount is less than 0.2 parts by mass, the intermolecular cross-linking of the polybutylene terephthalate is insufficient, and the mechanical strength tends to decrease. It rises remarkably and tends to impair moldability. A preferable content of the polymer (C) is preferably 0.25 parts by mass or more, preferably 2.8 parts by mass or less, and more preferably 2.0 parts by mass with respect to 100 parts by mass of the thermoplastic polyester resin (A). parts or less, more preferably 1.0 parts by mass or less.

[Glass fiber (D)]
The polybutylene terephthalate resin composition preferably contains glass fibers (D), and the amount thereof is preferably 10 to 100 parts by mass based on 100 parts by mass of the polybutylene terephthalate resin (A). If the content is less than 10 parts by mass, the reinforcing effect may not be sufficient, and if it exceeds 100 parts by mass, the appearance and impact resistance may be poor, and the fluidity may be insufficient. A preferable content of the glass fiber (D) is 45 parts by mass or more, more preferably 55 parts by mass or more, still more preferably 65 parts by mass or more, and particularly It is preferably 70 parts by mass or more, preferably 95 parts by mass or less, and more preferably 90 parts by mass or less. By containing the glass fiber (D) in this way, the strength, rigidity and dimensional stability of the molded article of the present invention can be improved.

The type of glass fiber (D) is not particularly limited, and examples thereof include glass fibers such as E glass, C glass, A glass, and S glass. Among these, E-glass fibers are preferred because they do not adversely affect the thermal stability of the polybutylene terephthalate resin.

Although the average fiber diameter of the glass fiber (D) is not particularly limited, it is preferably selected in the range of 1 to 100 µm, more preferably 2 to 50 µm, still more preferably 3 to 30 µm, particularly preferably 5 to 20 µm. Glass fibers with an average fiber diameter of less than 1 μm are not easy to manufacture and may be costly, while glass fibers with an average fiber diameter of more than 100 μm may have reduced tensile strength. The fiber cross section may be circular or flat.

The glass fiber (D) may have a circular cross section or a flattened fiber cross section. Preferably. The oblateness is preferably 1 to 1.4, more preferably 1 to 1.2, and particularly preferably 1 to 1.1.
The value of flattening is obtained by observing 2000 glass fibers of filler residue collected by processing such as high-temperature ashing, solvent dissolution, and chemical decomposition of the molded product with an optical microscope and an image analysis device. This is the calculated average value.

Although the average fiber length of the glass fibers (D) is not particularly limited, it is preferably 1 to 10 mm, more preferably 1.5 to 6 mm, and even more preferably 2 to 5 mm. If the average fiber length of the glass fibers (D) is less than 1 mm, the reinforcing effect may not be sufficiently exhibited, and if it exceeds 10 mm, molding of the resulting resin composition may become difficult.
The average fiber length was obtained by observing 2,000 glass fibers of filler residue collected by processing such as high-temperature incineration of the molded product, dissolution with a solvent, and decomposition with chemicals, using an optical microscope. It is the value of the calculated number average fiber length. In addition, when calculating such a value, the value is based on a method in which the fiber diameter is used as a guideline, and fibers with a length smaller than that are not counted.

The glass fiber (D) used in the present invention can be surface-treated with a coupling agent such as aminosilane or epoxysilane for the purpose of improving adhesion to the polybutylene terephthalate resin (A).
Examples of coupling agents include chlorosilane compounds such as vinyltrichlorosilane and methylvinyldichlorosilane; alkoxysilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and γ-methacryloxypropyltrimethoxysilane. compounds, epoxysilane compounds such as β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane, acrylic compounds, isocyanate compounds, titanate compounds, epoxy compounds, etc. can be mentioned.

In addition, the glass fiber (D) used in the present invention is preferably used as a chopped strand (chopped glass fiber) obtained by cutting a bundle of a large number of these fibers into a predetermined length. A sizing agent is preferably added to the fibers. By blending a sizing agent, in addition to the advantage of increasing the production stability of the polybutylene terephthalate resin composition and the molded article, good mechanical properties can be obtained.
The sizing agent for the glass fibers (D) is not particularly limited, and examples thereof include resin emulsions such as vinyl acetate resins, ethylene-vinyl acetate copolymers, acrylic resins, epoxy resins, polyurethane resins and polyester resins. , preferably acrylic resin, epoxy resin, or polyurethane resin.

As described above, the composition constituting the molded article of the present invention may be a composition containing at least the polybutylene terephthalate resin (A) and the styrenic copolymer (B) in predetermined amounts. Using other components, it is more preferable to have the following composition, for example.
Preferred composition (1):
Per 100 parts by mass of polybutylene terephthalate resin (A), 45 to 100 parts by mass of acrylonitrile-styrene copolymer (B1), 0.2 to 3 parts by mass of epoxy-modified acrylic polymer (C), and glass fiber (D) A polybutylene terephthalate resin composition containing 10 to 100 parts by mass.
Preferred composition (2):
Polybutylene terephthalate containing acrylonitrile-styrene copolymer (B1), epoxy-modified acrylonitrile-styrene copolymer (B2), and glass fiber (D) with respect to 100 parts by mass of polybutylene terephthalate resin (A) Resin composition.

In the preferred composition (2) described above, the content of the acrylonitrile-styrene copolymer (B1) and the epoxy-modified acrylonitrile-styrene copolymer (B2) is the total of the polybutylene terephthalate resin (A) It is preferably 45 to 100 parts by mass with respect to 100 parts by mass, and the mass ratio (B1)/(B2) of the content of (B1) and the content of (B2) is preferably 6 or less, and the glass fiber The content of (D) is preferably 10 to 100 mass.

In the preferred composition (2) described above, if the total content of (B1) and (B2) is less than 45 parts by mass, the ratio of the amorphous resin is low and the shrinkage rate increases, resulting in warping of the molded product. If it exceeds 100 parts by mass, the proportion of the amorphous resin is high, and in addition, the heat resistance tends to decrease, and the 85° C. atmosphere bending strength and weld strength tend to decrease. The total content of (B1) and (B2) is more preferably 50 parts by mass or more, more preferably 55 parts by mass or more, particularly preferably 60 parts by mass or more, and most preferably more than 65 parts by mass. It is preferably 95 parts by mass or less, more preferably 90 parts by mass or less. On the other hand, when the mass ratio (B1)/(B2) exceeds 6, the dispersion of the epoxy-modified acrylonitrile-styrene copolymer becomes insufficient, and the mechanical properties in a high temperature environment tend to deteriorate. (B1)/(B2) is more preferably 5 or less, more preferably 4 or less, more preferably 3 or less, particularly preferably 2 or less, and the lower limit thereof is preferably 0.5.

The content of the acrylonitrile-styrene copolymer (B1) alone is preferably 5 parts per 100 parts by mass of the polybutylene terephthalate resin (A), provided that the above mass ratio (B1)/(B2) is satisfied. It is preferably selected from the range of to 85 parts by mass.
The content of the epoxy-modified acrylonitrile-styrene copolymer (B2) alone is preferably based on 100 parts by mass of the polybutylene terephthalate resin (A), provided that the above mass ratio (B1)/(B2) is satisfied. is preferably selected from the range of 5 to 90 parts by mass.

[Other ingredients]
The above-described polybutylene terephthalate resin composition preferably used for the resin composition molded article of the present invention may contain thermoplastic resins other than essential components within a range that does not impair the effects of the present invention. Specific examples of other thermoplastic resins include polyethylene terephthalate resin, polycarbonate resin, polyacetal resin, polyamide resin, polyphenylene oxide resin, polyphenylene sulfide resin, polysulfone resin, polyethersulfone resin, polyetherimide resin, Examples include polyether ketone resins and polyolefin resins.
However, when resins other than essential components are contained, the content is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even 5 parts by mass with respect to 100 parts by mass of polybutylene terephthalate resin (A). It is preferably not more than 3 parts by mass, particularly not more than 3 parts by mass.

In addition, it may contain various additives other than those mentioned above. Examples of such additives include stabilizers, carbon black, release agents, flame retardants, flame retardant aids, anti-dripping agents, and ultraviolet absorbers. agents, antistatic agents, antifog agents, antiblocking agents, plasticizers, dispersants, antibacterial agents, colorants and the like.

[Stabilizer]
It is preferable that the polybutylene terephthalate resin composition contains a stabilizer because it has the effect of improving thermal stability and preventing deterioration of mechanical strength and hue. Phosphorus-based stabilizers, sulfur-based stabilizers and phenol-based stabilizers are preferred as stabilizers, and phenol-based stabilizers are particularly preferred.

Phosphorus-based stabilizers include phosphorous acid, phosphoric acid, phosphites (phosphites), trivalent phosphates (phosphonites), pentavalent phosphates (phosphates) and the like. Phytes, phosphonites and phosphate compounds are preferred.

The organic phosphate compound preferably has the following general formula:
(R ¹ O) _3-n P(=O)OH _n
(In the formula, R ¹ is an alkyl group or an aryl group, which may be the same or different. n represents an integer of 0 to 2.)
It is a compound represented by More preferably, R ¹ is a long-chain alkyl acid phosphate compound having 8 to 30 carbon atoms. Specific examples of alkyl groups having 8 to 30 carbon atoms include octyl group, 2-ethylhexyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group, A hexadecyl group, an octadecyl group, an eicosyl group, a triacontyl group and the like can be mentioned.

Examples of long-chain alkyl acid phosphates include octyl acid phosphate, 2-ethylhexyl acid phosphate, decyl acid phosphate, lauryl acid phosphate, octadecyl acid phosphate, oleyl acid phosphate, behenyl acid phosphate, phenyl acid phosphate, nonylphenyl acid phosphate, cyclohexyl Acid phosphate, phenoxyethyl acid phosphate, alkoxypolyethylene glycol acid phosphate, bisphenol A acid phosphate, dimethyl acid phosphate, diethyl acid phosphate, dipropyl acid phosphate, diisopropyl acid phosphate, dibutyl acid phosphate, dioctyl acid phosphate, di-2-ethylhexyl acid phosphate, dioctyl acid phosphate, dilauryl acid phosphate, distearyl acid phosphate, diphenyl acid phosphate, bisnonylphenyl acid phosphate and the like. Among these, octadecyl acid phosphate is preferred, and this product is commercially available from ADEKA under the trade name "ADEKA STAB AX-71".

The organic phosphite compound preferably has the following general formula:
R ² OP(OR ³ )(OR ⁴ )
(wherein R ² , R ³ and R ⁴ are each a hydrogen atom, an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms, and among R ² , R ³ and R ⁴ is an aryl group having 6 to 30 carbon atoms.)
The compound represented by is mentioned.

Examples of organic phosphite compounds include triphenylphosphite, tris(nonylphenyl)phosphite, dilaurylhydrogenphosphite, triethylphosphite, tridecylphosphite, tris(2-ethylhexyl)phosphite, tris(tridecyl ) phosphite, tristearyl phosphite, diphenyl monodecyl phosphite, monophenyl didecyl phosphite, diphenyl mono (tridecyl) phosphite, tetraphenyl dipropylene glycol diphosphite, tetraphenyl tetra (tridecyl) pentaerythritol tetraphosphite , hydrogenated bisphenol A phenol phosphite polymer, diphenyl hydrogen phosphite, 4,4′-butylidene-bis(3-methyl-6-tert-butylphenyl di(tridecyl)phosphite), tetra(tridecyl) 4,4 '-isopropylidene diphenyl diphosphite, bis (tridecyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, dilauryl pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tris(4- tert-butylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, hydrogenated bisphenol A pentaerythritol phosphite polymer, bis(2,4-di-tert-butylphenyl)pentaerythritol di Phosphites, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2′-methylenebis(4,6-di-tert-butylphenyl)octylphosphite, bis( 2,4-dicumylphenyl)pentaerythritol diphosphite and the like. Among these, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is preferred.

The organic phosphonite compound preferably has the following general formula:
R ⁵ -P(OR ⁶ )(OR ⁷ )
(wherein R ⁵ , R ⁶ and R ⁷ are each a hydrogen atom, an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms, and among R ⁵ , R ⁶ and R ⁷ is an aryl group having 6 to 30 carbon atoms.)
The compound represented by is mentioned.

Examples of organic phosphonite compounds include tetrakis(2,4-di-iso-propylphenyl)-4,4'-biphenylene diphosphonite, tetrakis(2,4-di-n-butylphenyl)-4,4'-biphenyl diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylenediphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,3'-biphenylenediphosphonite night, tetrakis(2,4-di-tert-butylphenyl)-3,3'-biphenylenediphosphonite, tetrakis(2,6-di-iso-propylphenyl)-4,4'-biphenylenediphosphonite, Tetrakis (2,6-di-n-butylphenyl)-4,4'-biphenylene diphosphonite, tetrakis (2,6-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, tetrakis ( 2,6-di-tert-butylphenyl)-4,3'-biphenylenediphosphonite, tetrakis(2,6-di-tert-butylphenyl)-3,3'-biphenylenediphosphonite, and the like. .

As the sulfur-based stabilizer, any conventionally known sulfur atom-containing compound can be used, and thioethers are particularly preferred. Specific examples include didodecylthiodipropionate, ditetradecylthiodipropionate, dioctadecylthiodipropionate, pentaerythritol tetrakis(3-dodecylthiopropionate), thiobis(N-phenyl-β-naphthylamine ), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, nickel dibutyldithiocarbamate, nickel isopropylxanthate, trilauryltrithiophosphite. Among these, pentaerythritol tetrakis(3-dodecylthiopropionate) is preferred.

Phenolic stabilizers include, for example, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4 -hydroxyphenyl)propionate, thiodiethylenebis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), pentaerythritol tetrakis(3-(3,5-di-neopentyl-4-hydroxyphenyl) ) propionate) and the like. Among these, pentaerythritol-letetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl ) propionate is preferred.

Among them, it is preferable to use a hindered phenol-based stabilizer having a melting point of 150°C or higher. When the melting point is 150° C. or higher, the stabilizer itself has high thermal stability, so that the stabilizer loses its stabilizing effect due to deterioration, and it may be used in a high-temperature environment such as during melt-kneading or the like during the production of a resin composition or injection molding. But less gas is produced. The melting point is more preferably 180° C. or higher, still more preferably 200° C. or higher, and particularly preferably 220° C. or higher. The upper limit of the melting point is usually 350°C or lower, preferably 300°C or lower, more preferably 280°C or lower.

One stabilizer may be contained, or two or more stabilizers may be contained in any combination and ratio.
The stabilizer content is preferably 0.001 to 1.5 parts by mass with respect to 100 parts by mass of the polybutylene terephthalate resin (A). If the content of the stabilizer is less than 0.001 part by mass, it is difficult to expect an improvement in the thermal stability and compatibility of the resin composition, and a decrease in molecular weight and deterioration in color during molding are likely to occur. If it exceeds the part, the amount becomes excessive, and silver streaks and deterioration of hue tend to occur more easily. The stabilizer content is more preferably 0.005 to 1.2 parts by mass, and still more preferably 0.01 to 1.0 parts by mass.

[Carbon black]
The polybutylene terephthalate resin composition also preferably contains carbon black. Containing carbon black improves the weather resistance and appearance of the molded product.
Carbon black is not limited in its type, raw material type, and production method, and any of furnace black, channel black, acetylene black, ketjen black, etc. can be used. Although the number average particle diameter is not particularly limited, it is preferably 5 to 60 nm. By using carbon black having a number-average particle size within a predetermined range, it is possible to obtain a composition that is less prone to blistering at high temperatures.
In addition, the number average particle diameter is obtained by obtaining an aggregate enlarged image according to the procedure described in ASTM D3849 standard (standard test method for carbon black-morphological characterization by electron microscopy), and from this aggregate image as unit constituent particles. It can be obtained by measuring 3,000 particle sizes and arithmetically averaging them.

The nitrogen adsorption specific surface area (unit: m ² /g) of carbon black is usually less than 1,000 m ² /g, preferably 50 to 400 m ² /g. A nitrogen adsorption specific surface area of less than 1,000 m ² /g tends to improve the fluidity of the polybutylene terephthalate resin composition and the appearance of the molded product, which is preferable. The nitrogen adsorption specific surface area can be measured according to JIS K6217.

DBP (dibutyl phthalate) absorption of carbon black is preferably less than 300 cm ³ /100 g, more preferably 30 to 200 cm ³ /100 g. A DBP absorption of less than 300 cm ³ /100 g tends to improve the fluidity of the polybutylene terephthalate resin composition and the appearance of the molded article, which is preferable. The DBP absorption (unit: cm ³ /100 g) can be measured according to JIS K6217.
The pH of the carbon black to be used is not particularly limited, but it is usually 2-10, preferably 3-9, more preferably 4-8.

Carbon black can be used singly or in combination of two or more. Furthermore, carbon black can be granulated using a binder, and can also be used in a masterbatch in which it is melt-kneaded into another resin at a high concentration. By using a melt-kneaded masterbatch, it is possible to achieve improved handleability during extrusion and improved dispersibility in the resin composition. Examples of the resin include polystyrene resins, polyester resins, acrylic resins, and the like.
The carbon black content in the masterbatch is preferably 10 to 80% by mass, more preferably 20 to 70% by mass, even more preferably 30 to 60% by mass.

The content of carbon black is preferably 0.01 to 5 parts by mass, more preferably 0.05 parts by mass or more, and still more preferably 0.08 parts by mass with respect to 100 parts by mass of the polybutylene terephthalate resin (A). In particular, it is 0.1 parts by mass or more, more preferably 2 parts by mass or less, still more preferably 1.5 parts by mass or less, and particularly preferably 1.0 parts by mass or less. If the content is less than 0.01 parts by mass, the weather resistance may be insufficient, and if it exceeds 5 parts by mass, mechanical properties such as moldability and impact resistance tend to deteriorate.

[Release agent]
The polybutylene terephthalate resin composition preferably contains a release agent.
Examples of release agents include aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds, and polysiloxane-based silicone oils.

Aliphatic carboxylic acids include, for example, saturated or unsaturated aliphatic monovalent, divalent or trivalent carboxylic acids. Here, the aliphatic carboxylic acid also includes alicyclic carboxylic acid. Among these, preferred aliphatic carboxylic acids are monovalent or divalent carboxylic acids having 6 to 36 carbon atoms, more preferably aliphatic saturated monovalent carboxylic acids having 6 to 36 carbon atoms. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetralyacontanoic acid, montanic acid, and adipine. acid, azelaic acid, and the like.

As the aliphatic carboxylic acid in the ester of aliphatic carboxylic acid and alcohol, for example, the same aliphatic carboxylic acid as mentioned above can be used. Alcohols, on the other hand, include, for example, saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have substituents such as fluorine atoms and aryl groups. Among these, monohydric or polyhydric saturated alcohols having 30 or less carbon atoms are preferable, and aliphatic saturated monohydric alcohols or saturated aliphatic polyhydric alcohols having 30 or less carbon atoms are more preferable. In addition, an alicyclic compound is also included with an aliphatic here.

Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, dipentaerythritol, and the like. is mentioned.

The above esters may contain aliphatic carboxylic acids and/or alcohols as impurities. Further, the above ester may be a pure substance, or may be a mixture of multiple compounds. Furthermore, the aliphatic carboxylic acids and alcohols that combine to form one ester may be used singly, or two or more of them may be used in any combination and ratio.

Specific examples of esters of aliphatic carboxylic acids and alcohols include montanic acid ester wax, beeswax (a mixture containing myricyl palmitate as a main component), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmite. Tate, glycerin monostearate, glycerin distearate, glycerin tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate, etc. .

Examples of the aliphatic hydrocarbon compound include liquid paraffin, paraffin wax, microcrystalline wax, polyolefin wax such as polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomers having 3 to 12 carbon atoms. In addition, an alicyclic hydrocarbon is also contained as an aliphatic hydrocarbon here. Also, these hydrocarbons may be partially oxidized. Also, the number average molecular weight is preferably 200 to 30,000, more preferably 1,000 to 15,000, still more preferably 1,500 to 10,000, and particularly preferably 2,000 to 5,000. The aliphatic hydrocarbon compound may be a single substance, or a mixture of various constituents and molecular weights can be used as long as the main component is within the above range.

In the present invention, polyolefin wax is preferable as the release agent from the viewpoint of heat resistance. Any conventionally known polyolefin wax can be used. A (co)polymer (meaning polymerization or copolymerization; the same shall apply hereinafter) containing more than one species may be mentioned.

Examples of olefins having 2 to 30 carbon atoms include ethylene, propylene, α-olefins having 4 to 30 carbon atoms (preferably 4 to 12, more preferably 4 to 10), and 4 to 30 carbon atoms (preferably 4 to 18, more preferably 4 to 8). Alpha-olefins include, for example, 1-butene, 4-methyl-1-pentene, 1-pentene, 1-octene, 1-decene and 1-dodecene. Examples of dienes include butadiene, isoprene, cyclopentadiene, 11-dodecadiene and the like.

As the polyolefin wax, polyethylene wax is preferable from the viewpoint of releasability and heat resistance.
Any method can be used to produce the polyethylene wax, and for example, it can be produced by polymerization of ethylene or thermal decomposition of polyethylene.

As the mold release agent, those having an acid value of 10 to 40 mgKOH/g are preferable from the viewpoints of low mold release resistance, remarkable effect of improving mold release properties, and low volatile content. The acid value is more preferably 11-35 mgKOH/g, more preferably 12-32 mgKOH/g. If the acid value is in the range of 10 to 40 mgKOH/g, one having an acid value of less than 10 mgKOH/g and one having an acid value of more than 40 mgKOH/g may be used in combination. It should be 10 to 40 mgKOH/g.

The release agent having an acid value of 10 to 40 mgKOH/g is preferably an ester of the above-described aliphatic carboxylic acid and alcohol having an acid value of 10 to 40 mgKOH/g, or the above-described aliphatic hydrocarbon compound. represents a carboxylic acid (anhydride) group, i.e., a carboxylic acid group and/or a carboxylic anhydride group; hereinafter the same), a haloformyl group, an ester group, a carboxylic acid metal base, a hydroxyl group, an alkosyl A modified polyolefin wax to which a functional group having an affinity for the polyester resin, such as a group, an epoxy group, an amino group, an amide group, etc., is added is preferable.

Carboxyl groups used for modifying polyolefin waxes include low molecular weight compounds containing carboxylic acid groups such as maleic acid, maleic anhydride, acrylic acid and methacrylic acid, low molecular weight compounds containing sulfo groups such as sulfonic acid, phosphonic Examples include low molecular weight compounds containing phospho groups such as acids. Among these, low-molecular-weight compounds containing carboxylic acid groups are preferred, and maleic acid, maleic anhydride, acrylic acid, and methacrylic acid are particularly preferred. These carboxylic acids may be used singly or in combination of two or more at any ratio.
The amount of acid added to the modified polyolefin wax is generally 0.01 to 10% by mass, preferably 0.05 to 5% by mass, based on the modified polyolefin wax.

Specific examples of the haloformyl group include a chloroformyl group and a bromoformyl group. The means for imparting these functional groups to the polyolefin wax may be any conventionally known method, specifically, for example, copolymerization with a compound having a functional group, post-processing such as oxidation, method may be used.

As for the type of functional group, a carboxyl group is preferable because it has an appropriate affinity with the polyester resin. The concentration of carboxyl groups in the modified polyolefin wax may be appropriately selected and determined, but if it is too low, the affinity with the polyester resin will be low, the effect of suppressing volatile matter will be small, and the release effect will be reduced. There is Conversely, if the concentration is too high, for example, the polymer main chain that constitutes the polyolefin wax is excessively cut during modification, and the molecular weight of the modified polyolefin wax is too low, resulting in increased volatile matter generation and polyester resin. Clouding may occur on the surface of the molded product.
As the modified polyolefin wax, oxidized polyethylene wax is preferred.

One release agent may be contained, or two or more release agents may be contained in any combination and ratio.
The content of the release agent is usually 0.001 parts by mass or more, preferably 0.01 parts by mass or more, and usually 2 parts by mass or less, preferably It is 1.5 parts by mass or less. If the content of the release agent is less than the lower limit of the above range, the releasability effect may not be sufficient, and if the content of the release agent exceeds the upper limit of the above range, hydrolysis resistance may cause a decrease in the product, mold contamination during injection molding, and the like.

[Method for producing resin composition]
As a method for producing the polybutylene terephthalate resin composition, a conventional method for preparing a polybutylene terephthalate resin composition can be used. That is, polybutylene terephthalate resin (A), acrylonitrile-styrene copolymer (B1) and/or epoxy-modified acrylonitrile-styrene copolymer (B2), and optionally added other resin components and various The additives are well mixed together and then melt-kneaded in a single or twin screw extruder. The glass fibers (D) are preferably side-fed. Alternatively, a masterbatch of a part thereof may be blended and melt-kneaded. Furthermore, it is also possible to supply a mixture obtained by mixing each component in advance to a molding machine such as an injection molding machine as it is without melt-kneading to produce various molded products.

The heating temperature for melt-kneading can be appropriately selected from the range of 220 to 300°C. If the temperature is too high, decomposition gas is likely to be generated, which may cause poor appearance. Therefore, it is desirable to select a screw structure in consideration of shear heat generation and the like. In order to suppress decomposition during kneading and subsequent molding, it is desirable to use antioxidants and heat stabilizers.

The raw material polybutylene terephthalate resin composition is heat-treated at 270° C. for 10 minutes, and the amount of styrene-based monomer detected when the gas generated is analyzed with a gas chromatograph is 45 (mass) ppm or less. preferable. By setting the styrene-based monomer gas content of the resin composition to 45 ppm or less, the problem of VOCs can be solved even when the resin composition is used as a vehicle interior part, and the appearance during molding is improved. On the other hand, if it exceeds 45 ppm, the cleanness of the vehicle interior parts deteriorates, it becomes difficult to solve the VOC problem, and the external appearance during molding tends to be poor. The amount of styrenic monomer gas in the resin composition is preferably 30 ppm or less, more preferably 20 ppm or less, and the lower limit is usually 2 ppm.
The amount of styrene-based monomer gas in the resin composition can be obtained by analyzing the gas generated by heat treatment at 270° C. for 10 minutes with a gas chromatograph. is the amount (unit: mass ppm) obtained by converting the value of, and the specific conditions are as described in detail in the examples.

In addition, the polybutylene terephthalate resin composition as a raw material is heat-treated at 270° C. for 10 minutes, and the amount of ethylbenzene detected when the gas generated is analyzed by gas chromatography is preferably 3 (mass) ppm or less. preferable. By doing so, the problem of VOC can be solved even when the molded product is used as a vehicle interior part, and the appearance of the molded product is also improved.
The amounts of styrene and ethylbenzene in the resin composition were obtained by analyzing the gas generated by heat treatment at 270° C. for 10 minutes, as described above, using a gas chromatograph. It is an amount (unit: mass ppm) converted into a value per amount of substance. The specific assumption method and conditions are as described in detail in the examples.

In addition, the polybutylene terephthalate resin composition is heat-treated at 270° C. for 10 minutes, and the total amount of styrene-based monomers and ethylbenzene detected when the gas generated is analyzed by gas chromatography is 45 (mass) ppm or less. is preferably By doing so, the problem of VOC can be solved even when used as vehicle interior parts, etc., and the appearance at the time of molding is also improved. The total amount of the styrenic monomer and ethylbenzene in the resin composition is preferably 30 ppm or less, more preferably 20 ppm or less, and the lower limit is usually 3 ppm.

In order to make the styrene monomer gas content of the resin composition 45 ppm or less, the styrene monomer gas content of 600 ppm or less, preferably 550 ppm or less is used as the styrene copolymer (B) described above. Further, it is possible by blending the phosphite-based stabilizer or the hindered phenol-based stabilizer described above.
Further, the amount of ethylbenzene gas in the resin composition can be reduced to 3 ppm or less by, for example, blending the phosphite-based stabilizer or hindered phenol-based stabilizer described above.

[Molded body]
The method for producing a molded article using the polybutylene terephthalate resin composition described above is not particularly limited, and any molding method commonly used for polybutylene terephthalate resin compositions can be employed. Injection molding method, injection compression molding method, two-color molding method, hollow molding method such as gas assist, molding method using heat insulating mold, molding method using rapid heating mold, foam molding (including supercritical fluid) , insert molding, IMC (in-mold coating molding) molding method, extrusion molding method, sheet molding method, thermoforming method, rotational molding method, laminate molding method, press molding method, blow molding method, etc., but injection molding method is preferred.

As described above, the molded article of the present invention has a sea-island structure, and the polybutylene terephthalate resin (A) forms a continuous phase,
Domains containing the styrene-based copolymer (B) are dispersed in the form of islands in the continuous phase of the polybutylene terephthalate resin (A), and the islands contain the phase of the polybutylene terephthalate resin (A). exists as a lake, and has a morphology in which the maximum width of the island is 6 μm or less.

As a preferred method for producing a molded article having such a morphology, for example, 45 to 100 parts by mass of the styrene copolymer (B) is added to 100 parts by mass of the polybutylene terephthalate resin (A), and more preferably can be injection-molded using a resin composition obtained by blending these with the epoxy-modified acrylic polymer (C). By using the epoxy-modified acrylic polymer (C), the compatibility of the styrene copolymer (B) with the polybutylene terephthalate resin (A) is improved, so that a high degree of dispersion progresses and the morphology of the present invention is obtained. can be

In order to achieve the above morphology, a particularly preferable blending composition of the polybutylene terephthalate resin composition is, for 100 parts by mass of the polybutylene terephthalate resin (A), 45 to 100 parts by mass of the styrene copolymer (B), epoxy-modified 0.2 to 3 parts by mass of the acrylic polymer (C) and 10 to 100 parts by mass of the glass fiber (D).

Further, as another preferred method for producing a molded article having the above morphology, acrylonitrile-styrene copolymer (B1) and epoxy-modified acrylonitrile-styrene copolymer are added to 100 parts by mass of polybutylene terephthalate resin (A). Injection molding can be performed using a resin composition containing a total of 45 to 100 parts by mass of coalescence (B2) and a mass ratio (B1)/(B2) of contents of (B1) and (B2) of 6 or less. mentioned. By using the epoxy-modified acrylonitrile-styrene-based copolymer (B2), the acrylonitrile-styrene-based copolymer (B1) is more compatible with the polybutylene terephthalate resin (A), so that a high degree of dispersion progresses. , can be the morphology of the present invention.

Injection molding conditions are preferably such that the pellets of the polybutylene terephthalate resin composition are sufficiently dried by increasing the drying temperature or lengthening the drying time. It is preferable that the temperature is 70 to 90° C., the cooling time is 15 to 25 seconds, the filling time is 0.5 to 1.5 seconds, and the holding pressure is about 40 to 80% of the injection peak pressure.

The TVOC content of the molded article of the present invention is 30 μgC/g or less, more preferably 20 μgC/g or less.
In order to achieve the above TVOC content in the molded product, the above styrene copolymer (B) should have a styrene monomer gas content of 600 ppm or less, preferably 550 ppm or less. This is possible by, for example, adding a phyto-based stabilizer or a hindered phenol-based stabilizer.
A specific method for measuring the amount of TVOC in the molded product is as described in detail in Examples.

The shape of the molded article is not particularly limited, and can be appropriately selected according to the application and purpose of the molded article. Circular, elliptical, polygonal, odd-shaped, hollow, frame-shaped, box-shaped, panel-shaped and the like can be mentioned.

Since the molded article of the present invention has low warpage, little gas generation, excellent mechanical properties at high temperatures, and low specific gravity, it can be particularly suitably used as a vehicle interior part where these properties are strictly required.

Vehicle interior parts are interior parts for vehicles such as automobiles, trains, trains, etc. Inner mirror stays, wave louvers for air conditioners, door handles, handles, doors, sunroofs, seat belts, register blades, etc. Washer levers, window regulator handles, knobs for window regulator handles, passing light levers, sun visor brackets, various housings, switches, clips and the like are preferred.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention should not be construed as being limited to the following examples.
The components used in the following examples and comparative examples are shown in Table 1 below.

[Production example of acrylonitrile-styrene copolymer (B1-1)]
The first reactor, which is a complete mixing tank, and the second reactor, which is a tower-type plug flow reactor with a stirrer, are connected in series, and two devolatilization tanks with preheaters are connected in series. Configured. 15 parts by mass of ethylbenzene, 0.01 parts by mass of t-butylperoxyisopropyl monocarbonate, and 0.25 parts by mass of t-dodecylmercaptan are mixed with 85 parts by mass of a monomer solution containing 30% by mass of acrylonitrile and 70% by mass of styrene. and used as a raw material solution. This raw material solution was introduced into the first reactor controlled at 130° C. at 6.0 kg/h. The reaction liquid was continuously withdrawn from the first reactor and introduced into the second reactor. Next, it was heated to 160°C with a preheater and then introduced into the first devolatilization tank evacuated to 65 kPa. Residual monomer and solvent were removed. This was extruded and cut into strands to obtain acrylonitrile-styrene copolymer (B1-1) in the form of pellets. The composition (mass ratio of monomer units) of the copolymer (B1-1) was, as shown in Table 1, 30% by mass of acrylonitrile units and 70% by mass of styrene units.

[Production example of epoxy-modified acrylonitrile-styrene copolymer (B2)]
Acrylonitrile, styrene and glycidyl methacrylate were subjected to suspension polymerization to prepare a bead-like glycidyl methacrylate-modified acrylonitrile-styrene copolymer (B2). The proportion of each component in this copolymer was 25/75/0.4% by mass in terms of acrylonitrile/styrene/glycidyl methacrylate.

The mass average molecular weight (Mw) of the acrylonitrile-styrene copolymer and the acrylonitrile copolymerization amount (% by mass, "PAN ratio") in Table 1 above were measured by the methods described above. In addition, MVR is the melt flow volume MVR per unit time measured using a melt indexer manufactured by Takara Industries Co., Ltd. under the conditions of 220 ° C. and a load of 2.16 kgf for the pellets obtained above (unit: cm ³ / 10 min) was measured.

[Measurement of styrene content and ethylbenzene content]
The acrylonitrile-styrene copolymer used was measured for styrene content and ethylbenzene content. The gas generated by the Desorption method) was analyzed by the following chromatography.
Measuring instrument: GCMS-QP2010 (manufactured by Shimadzu Corporation)
Column: UA-1701 inner diameter 0.25 mm
Carrier gas: He
Pressure: 80kPa
Column flow rate: 1.4 mL/min
Column oven temperature: 50°C
Vaporization chamber temperature: 25°C
Detector: Secondary electron multiplier with conversion dynode Ion source temperature: 250°C

(Examples 1 to 5, 7, 9 to 12, Reference Examples 6 and 8, Comparative Examples 1 to 5)
After uniformly mixing each component shown in Table 1 in the ratio shown in Table 2 and below (all parts by mass) in a tumbler mixer, using a twin-screw extruder (“TEX30α” manufactured by Japan Steel Works, Ltd.), The resin composition melted and kneaded under conditions of a set cylinder temperature of 260° C. and a screw rotation speed of 200 rpm was rapidly cooled in a water tank and pelletized using a pelletizer to obtain pellets of a polybutylene terephthalate resin composition.
Next, the obtained pellets of the polybutylene terephthalate resin composition are dried at 120° C. for 8 hours using a hot air dryer, and a flat plate of 100 mm long × 100 mm wide × 3 mm thick is molded into an injection molding machine (Nissei Plastic Industry Co., Ltd.) "NEX80"), using a film gate mold, cylinder temperature 260 ° C, mold temperature 80 ° C, cooling time 20 seconds, filling time 1.0 seconds, 50% of the injection peak pressure is the holding pressure value Injection molding was performed under the following conditions.
Comparative Example 3 could not be molded because the viscosity was too high.

[Morphology Observation]
From the cross section parallel to the flow direction during molding, including the center point of 50 mm in length and 50 mm in width of the flat plate obtained above and having a thickness of 1.5 mm, Leica "UC7" was used. A block-shaped sample having an observation surface of 500 μm long×500 μm wide and a thickness of about 1 cm was cut out using a diamond knife. After staining the observed surface of the obtained sample with ruthenium tetroxide in the gas phase at room temperature for 120 minutes, a scanning electron microscope (manufactured by Hitachi High-Tech Co., Ltd., "SU8020") was used, an acceleration voltage of 1 kV, a signal LA100 (U), An SEM image at a magnification of 3000 times was acquired under the conditions of an emission current of 10 μA and a probe current of Normal.
From the obtained SEM image, the presence or absence of lakes of polybutylene terephthalate resin and whether the island-shaped portions have a plurality of branched portions were observed for the island-shaped portions containing the styrene-based copolymer (B). The maximum width of the island portion was measured by the method described above.
In addition, from the obtained SEM image, [the total area of all island-shaped parts (this area does not include the area of the lake)] The ratio (%) of the total of the area of the part (this area does not include the area of the lake)] was obtained. As described above, as the “island-shaped portion having a lake”, an island-shaped portion having a lake with a major axis of 1 μm or more in the field of view of the SEM image (magnification: 3000) was adopted.
The SEM image used for analysis was a field of view with a magnification of 3000 times, and when there was glass fiber in the resin composition in the field of view, an image was selected in which the cross-sectional area of the glass fiber was 10% or less of the field of view.

SEM images (magnification: 3000) of the molded bodies of Examples 1 to 4, 7, 9 and 11 by a scanning electron microscope are shown in FIGS.
SEM images of the compacts of Comparative Examples 1, 2 and 4 obtained by a scanning electron microscope (magnification: 3000) are shown in FIGS.

[Measurement of TVOC of compact]
The molded product obtained above was cut into 10 to 25 mg pieces, and about 2 g of each sample was placed in a 22 ml vial, sealed, and subjected to HS-GC (headspace gas chromatograph mass spectrometer) at 120° C. for 5 hours. A heat treatment was performed. Then, the peak integrated area of the volatile organic components detected by the gas chromatograph was calculated, weight conversion was performed using acetone as a standard, and the TVOC (unit: μgC/g) per 1 g of the molded product was obtained.

<Evaluation of Resin Composition>
[Measurement of styrene content and ethylbenzene content]
The styrene content and ethylbenzene content of the resulting polybutylene terephthalate resin composition were measured by placing 0.02 g of a sample in a glass collection tube having an outer diameter of 6.35 mm and a length of 90 mm and heat-treating it at 270°C for 10 minutes ( The gas generated by Thermal Desorption method) was measured by the following chromatograph. The measured value was converted into a value per amount of copolymer or resin composition, and the amount of styrene and ethylbenzene generated (unit: mass ppm) was defined.
Measuring instrument: GCMS-QP2010 (manufactured by Shimadzu Corporation)
Column: UA-1701 inner diameter 0.25 mm
Carrier gas: He
Pressure: 80kPa
Column flow rate: 1.4 mL/min
Column oven temperature: 50°C
Vaporization chamber temperature: 25°C
Detector: Secondary electron multiplier with conversion dynode Ion source temperature: 250°C

[Standing thickening property (appearance evaluation of staying strand)]
Using a capillograph (Capilograph 1C manufactured by Toyo Seiki Co., Ltd.), using a flat capillary of 1φ×30 mm at a measurement temperature of 270° C., the pellets obtained above were put in, retained for 30 minutes, and sheared at a shear rate of 91.2 sec ⁻¹ . A strand (retained strand) produced by extrusion was obtained, and its appearance was judged according to the following four stages A to D.
A: Gloss observed on strand surface, good appearance B: Slight gloss observed on strand surface, slightly poor appearance C: No gloss observed on strand surface, appearance poor D: Strand cannot be produced, appearance Unevaluable

<Evaluation of compact>
[85°C Atmosphere Bending Strength]
After drying the pellets obtained above at 120 ° C. for 5 hours, an ISO multi-purpose test was performed with an injection molding machine ("NEX80" manufactured by Nissei Plastic Industry Co., Ltd.) at a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C. Pieces (4 mm thick) were injection molded.
Bending strength (maximum bending stress, unit: MPa) was measured at a temperature of 85° C. according to ISO 178 using an ISO multipurpose test piece (4 mm thick).

[Warp amount]
Using an injection molding machine ("NEX80" manufactured by Nissei Plastic Industry Co., Ltd.), a cylinder temperature of 260 ° C and a mold temperature of 80 ° C are used to mold a circular plate with a diameter of 100 mm and a thickness of 1.6 mm using a side gate mold. The warp amount (unit: mm) of the plate was determined.

[Comprehensive evaluation]
Comprehensive evaluation is judged according to the following criteria.
A: "Warpage amount of 5.0 mm or less", "85 ° C atmosphere bending strength of 120 MPa or more" for evaluation of molded body, "55 ppm or less of generated styrene and ethylbenzene" for evaluation of resin composition, "Retention thickening property is All conditions of A or B are met.
B: None of A above and C below.
C: Evaluation of molded product "warp amount of 6.0 mm or more", "85 ° C atmosphere bending strength less than 120 MPa", evaluation of resin composition "styrene and ethylbenzene generation amount over 55 ppm", "retention thickening property falls under any of D.
The above evaluation results are shown in the table below.

The polybutylene terephthalate resin composition molded article of the present invention has little warpage, generates little gas, can clear VOC regulations, and has excellent bending strength at high temperatures. It can be suitably used as an interior component for vehicles such as.

Claims (4)

Per 100 parts by mass of polybutylene terephthalate resin (A), 45 to 100 parts by mass of acrylonitrile-styrene copolymer (B1), 0.2 to 3 parts by mass of epoxy-modified acrylic polymer (C), and glass fiber ( D) A molded article having a sea-island structure and a minimum thickness of more than 1 mm, made of a polybutylene terephthalate resin composition containing 10 to 100 parts by mass ,
The total amount of styrene-based monomers and ethylbenzene detected when the gas generated by heat-treating the polybutylene terephthalate resin composition at 270° C. for 10 minutes is analyzed by gas chromatography is 30 mass ppm or less,
Polybutylene terephthalate resin (A) forms a continuous phase,
Domains containing the acrylonitrile- styrene copolymer (B 1 ) are dispersed in the form of islands in the continuous phase of the polybutylene terephthalate resin (A), and at least some of the domains are polybutylene in the islands. The phase of the terephthalate resin (A) exists as a lake, and has a morphology in which the maximum width of the island-shaped portions measured by the following method is 6 μm or less,
The amount of volatile organic compounds (TVOC) detected when the gas generated by heat-treating the molded body at 120 ° C. for 5 hours is analyzed by gas chromatography is 30 μg C / g or less.
A polybutylene terephthalate resin composition molded article characterized by:
How to measure the maximum width of the island:
The maximum value of the width of the island-like portion is measured from the SEM image (magnification: 3000) of the cross section including the central point in the thickness direction of the portion where the thickness of the molded body is the maximum. 2. The polybutylene terephthalate resin composition molded article according to claim 1, wherein at least a part of the island-shaped portion of the polybutylene terephthalate resin (A) is an island-shaped portion having a branched portion. 3. The molded article of polybutylene terephthalate resin composition according to claim 1, wherein the amount of TVOC from the molded article is 20 μgC/g or less. The molded article according to any one of claims 1 to 3 , which is a vehicle interior part.

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