TW201716502A - Thermoplastic polyester resin composition and molded article - Google Patents

Abstract

Disclosed are: a thermoplastic polyester resin composition comprising a thermoplastic polyester resin and an AS resin, wherein the ratio of a peak area at 1573 cm-1 to a peak area at 1450 cm-1 in an IR spectrum of the AS resin which is obtained by an IR measurement after the melt heating of the AS resin in air at a temperature of 260 DEG C for 30 minutes is 2.30% or less, and the AS resin is produced by bulk polymerization; and a molded article produced by the injection molding of the thermoplastic polyester resin composition.

Description

Thermoplastic polyester resin composition and molded article

The present invention relates to a resin composition comprising a thermoplastic polyester such as a polybutylene terephthalate resin, and a molded article obtained by injection molding.

The thermoplastic polyester resin is used for various applications such as electrical, electronic parts, and automobile parts because of its high heat distortion temperature, excellent electrical properties, mechanical properties, weather resistance, water resistance, and chemical resistance. Among the thermoplastic polyester resins, injection molding of a crystalline resin such as polybutylene terephthalate resin (hereinafter also referred to as "PBT resin") is known as a cooling and solidification process in a metal mold. Forming shrinkage occurs due to crystallization of the resin, which causes molecular alignment. When the molding shrinkage occurs uniformly in the entire molded article, the molded article which is only one turn smaller than the metal mold is completed. However, in most cases, the size of the shrinkage varies in each part of the molded article, and the molded article is deformed such as being bent or twisted.

The above-mentioned difference in shrinkage can be roughly divided into two reasons. First, the difference in wall thickness in the molded article (relative to the higher shrinkage ratio of the upper thick portion and the lower shrinkage ratio of the thin portion) is caused by the design. The other is the anisotropy due to the shrinkage of the material itself.

In addition, the anisotropy of the shrinkage rate of the material itself is caused by the alignment of the filler such as glass fiber and the alignment of the molecular chain of the resin itself. From the direction of fibrous fillers or molecular chains" It is easy to shrink, and on the other hand, "in the direction of compressing the fibrous filler or the molecular chain" is not easily contracted to cause anisotropy. Here, regarding the anisotropy of the filler from the former, it is known that the shape of the filler is not a fibrous shape but a shape having a small aspect ratio of a plate shape or a granular shape, and the latter is different from the molecular alignment. The directionality is a measure for inhibiting the crystallization of molecules, and it is known to alloy with an amorphous resin. For the amorphous resin to be alloyed, for example, an acrylonitrile-styrene copolymer (hereinafter also referred to as "AS resin") (see JP-A-2006-16558).

On the other hand, a resin composition described in JP-A-H06-57092 or JP-A-2001-240737 is known, for example, from the resin composition of the AS resin. Japanese Laid-Open Patent Publication No. Hei 6-57092 discloses a resin composition comprising a PBT resin, an ABS resin, an AS resin produced by bulk polymerization, and an improved melt flow state in a state in which good impact resistance characteristics are maintained. In addition, it is described that the ABS resin produced by bulk polymerization does not substantially contain an alkali metal salt or the like, and the thermal stability can be favorably maintained (i.e., due to the fact that it is not an AS resin). The hue caused by heat is less.)

[Advanced technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2006-16558

[Patent Document 2] Japanese Patent Laid-Open No. Hei 6-57092

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2001-340737

Japanese Laid-Open Patent Publication No. 2006-16558 discloses a resin composition in which a predetermined amount of an amorphous resin such as a polyester resin or an AS resin, a predetermined glass fiber or an epoxy compound is blended, thereby improving the machine. Improvement in physical properties and low bendability, but the addition of the AS resin alone may not sufficiently reduce the effect of bending, or may cause discoloration due to heat. Regarding the discoloration by heat, Japanese Laid-Open Patent Publication No. 2001-240737 discloses that ABS resin produced by bulk polymerization can be used to maintain thermal stability well, but according to the study of the present applicant, it is produced by using block polymerization. In the case of AS resin, discoloration due to heat may occur, and it is not a perfect countermeasure.

The present invention has been made in view of the above circumstances, and an embodiment of the present invention provides a thermoplastic polyester resin composition which is capable of forming a molded article which is bendable and has little discoloration due to heat, and injection molding of the resin composition. The molded article is a problem.

The present inventors have repeatedly studied in order to solve the above problems. As a result, it has been found that a thermoplastic resin having a small tri-chain structure derived from acrylonitrile and an AS resin produced by bulk polymerization can be formed into a molded article having a small amount of discoloration due to heat. The present invention has been completed.

The embodiment of the present invention includes the following thermoplastic resin composition and molded article.

(1) A thermoplastic polyester resin composition comprising: a thermoplastic polyester resin; and an AS resin, wherein the AS resin is an IR spectrum obtained by IR measurement after being melt-heated at 260 ° C for 30 minutes in air, 1573 cm The ratio of the peak area of ^{-1 to} the peak area of 1450 cm ^-1 was 2.30% or less, and was produced by a block polymerization.

(2) The thermoplastic polyester resin composition according to the above (1), wherein the thermoplastic resin composition has a resin temperature of 260 ° C, a mold temperature of 60 ° C, a holding pressure of 60 MPa, and a side of 4 mm × 2 mmt. The flatness of the 120 mm × 120 mm × 2 mmt flat plate formed by the gate injection was 3.0 mm or less.

(3) A molded article obtained by injection molding the thermoplastic polyester resin composition according to (1) or (2) above.

(4) The molded article according to the above (3), wherein either one of the longitudinal direction, the transverse direction, and the height is a box shape or a flat plate shape of 10 mm or more.

According to the embodiment of the present invention, it is possible to provide a thermoplastic polyester resin composition which can be molded and bent, and a molded article having little discoloration due to heat, and a molded article obtained by injection molding the resin composition.

Fig. 1 is an IR spectrum of an AS resin ("AS resin 1" used in Example 1) measured by a micro Fourier transform infrared spectrometer.

Fig. 2 is a plan view of a test piece for measuring flatness.

Fig. 3 is a graph showing the relationship between the flatness of the molded article and the ratio (AN ratio) of acrylonitrile to the AS resin used in each of the Examples and Comparative Examples.

Fig. 4 is a graph showing the relationship between the flatness and the MFR of the AS resin used in each of the examples and the comparative examples.

Fig. 5 is a graph showing the relationship between the flatness and the average particle diameters of the AS resins used in Examples 1, 2 and Comparative Example 1.

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

<Thermoplastic Polyester Resin Composition>

The thermoplastic polyester resin composition of the embodiment of the present invention (hereinafter also referred to simply as "resin composition") is characterized by comprising: a thermoplastic polyester resin; and an AS resin (acrylonitrile-styrene copolymerization) The above-mentioned AS resin is obtained by IR heating at 260 ° C for 30 minutes in air, and the IR spectrum obtained by IR measurement has a ratio of a peak area of 1573 cm ^{-1 to} a peak area of 1450 cm ^-1 of 2.30% or less, and Block polymer manufacturer.

The resin composition of the embodiment of the present invention is alloyed with the AS resin as described above by a thermoplastic polyester resin, and can be molded into a molded article which is less likely to be bent and which has less discoloration due to heat.

Hereinafter, each component of the resin composition according to the embodiment of the present invention will be described.

[Thermoplastic polyester resin]

The thermoplastic polyester resin is a dicarboxylic acid component containing a dicarboxylic acid compound and/or an ester-forming derivative thereof as a main component, and a diol compound and/or an ester-forming derivative thereof as a main component. A thermoplastic polyester resin obtained by reacting an alcohol component.

The dicarboxylic acid component may, for example, be an aliphatic dicarboxylic acid (for example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, ten). a C _4-40 dicarboxylic acid such as dialkyl dicarboxylic acid, hexadecandicarboxylic acid or dimer acid, preferably a dicarboxylic acid having a carbon number of 4 to 14 or more, and an alicyclic dicarboxylic acid ( For example, a C _4-40 dicarboxylic acid such as hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid or 5-norbornene-2,3-dicarboxylic acid, _8-12 or so dicarboxylic acid is preferred), aromatic dicarboxylic acid (for example, phthalic acid, isophthalic acid, terephthalic acid, methyl isophthalic acid, methyl terephthalic acid, 2 a naphthalene dicarboxylic acid such as 6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-diphenoxy ether dicarboxylic acid, 4,4'-dioxybenzoic acid, a C _8-16 dicarboxylic acid such as 4,4'-diphenylmethane dicarboxylic acid or 4,4'-benzophenone dicarboxylic acid, or such a derivative (for example, a lower alkyl ester, An ester-forming derivative of an aryl ester, an acid anhydride or the like). These dicarboxylic acid components can be used individually or in combination of 2 or more types. The preferred dicarboxylic acid component contains an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid or naphthalene dicarboxylic acid (particularly terephthalic acid or 2,6-naphthalenedicarboxylic acid). The dicarboxylic acid component is, for example, preferably 50 mol% or more, more preferably 80 mol% or more, and more preferably 90 mol% or more of the aromatic dicarboxylic acid. Further, if necessary, a polyvalent carboxylic acid such as triphenylhexacarboxylic acid or tetraphenylhexacarboxylic acid or an ester thereof may be used in combination to form a derivative (alcohol ester or the like). By using such a polyfunctional compound, it is also possible to score a branched thermoplastic polyester resin.

The diol component may, for example, be an aliphatic alkanediol (for example, ethylene glycol, trimethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butylene glycol, neopentyl glycol, or a C _2-12 aliphatic diol such as a diol, an octanediol or a decanediol, or an aliphatic diol having a C _2-10 or so, or a polyoxyalkylene glycol (alkylene group) around C _2-4, having a plurality of oxyalkylene glycol units, such as diethylene glycol, dipropylene glycol, di (tetramethylene) glycol, triethylene glycol, tripropylene glycol, alkylene glycol forty-four An alcohol or the like), an alicyclic diol (for example, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.). In addition, hydroquinone, resorcinol, bisphenol, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-(2-hydroxyethoxy)phenyl) may also be used in combination. An aromatic diol such as propane or xylene glycol. These diol components may be used alone or in combination of two or more. Preferably the diol component, comprising C _{2 ~ 10} alkylene glycols (ethylene glycol, trimethylene glycol, propylene glycol, 1,4-butanediol linear alkylene glycols) and the like. In the diol component, for example, comprise more than 50 mole%, preferably at least 80 mole%, 90 mole% or more of C _{2 ~ 10} alkylene glycol better. Further, a polyhydric alcohol such as glycerin, trimethylolpropane, trimethylolethane or isovaerythritol or an ester-forming derivative thereof may be used in combination as needed. By using such a polyfunctional compound, it is also possible to score a branched thermoplastic polyester resin.

The thermoplastic polyester resin may be a combination of two or more kinds of the above-mentioned dicarboxylic acid component and a diol component, or another copolymerizable monomer such as an oxycarboxylic acid component or a lactone component (hereinafter, A copolyester such as a copolymerizable monomer).

In the oxycarboxylic acid (or oxycarboxylic acid component or oxycarboxylic acid), for example, an oxycarboxylic acid such as oxygen benzoic acid, oxynaphthic acid, hydroxyphenylacetic acid, glycolic acid, oxycaproic acid or the like or a derivative thereof Wait. In the lactone, C _3-12 lactone or the like containing propiolactone, butyrolactone, valerolactone, caprolactone (for example, ε caprolactone, etc.), or the like.

Further, in the copolyester, the ratio of the copolymerizable monomer can be selected, for example, to a range of from 0.01 mol% to 30 mol%, and usually from 1 mol% to 30 mol%. The degree is preferably 3 mol% or more and 25 mol% or less, and more preferably 5 mol% or more and 20 mol% or less. In addition, when the homopolyester and the copolyester are combined, the ratio of the homopolyester to the copolyester is the ratio of the copolymerizable monomer to the total monomer, which is 0.1 mol% or more and 30 mol% or less (to 1 mol) The range of the ear% or more is preferably not more than 25 mol%, and more preferably 5 mol% or more and 25 mol% or less. Usually, the former/the latter = 99/1 to 1/99 (mass ratio), 95/5~5/95 (mass ratio) is preferred, The range of 90/10~10/90 (mass ratio) is better.

A preferred thermoplastic polyester resin comprising an alkylene glycolate unit such as an alkylene terephthalate or an alkylene naphthalate as a main component (for example, 50 to 100 mol%, a homopolyester or copolyester of about 75 to 100 moles per mole [for example, polyalkylene terephthalate (for example, polyethylene terephthalate (PET), polyparaphenylene) Triethylene glycol formate (PTT), polybutylene terephthalate (PBT), etc., C _2-4 alkylene glycol ester), 1,4-terephthalic acid Cyclohexane dimethylene glycol (PCT), polyalkylene naphthalate (for example, polyethylene naphthalate, propylene glycol naphthalate, butylene glycol naphthalate) a homopolyester of a poly(phthalic acid C _2-4 alkylene glycol ester) such as an ester; containing an alkylene terephthalate and/or an alkylene naphthalate as a main component ( For example, 50% by mole or more of the copolyester] may be used alone or in combination of two or more.

Particularly preferred thermoplastic polyester resin comprising ethylene terephthalate, trimethylene glycol terephthalate, tetramethylene glycol terephthalate, 2,6-naphthalene dicarboxylic acid A homopolyester resin or a copolyester resin (for example, polyparaphenylene) having an aromatic acid C _2-4 alkylene ester such as tetramethylene glycol ester in an amount of 80 mol% or more (particularly 90 mol% or more) Ethylene glycol dicarboxylate resin, trimethylene glycol terephthalate, polybutylene terephthalate resin, poly 2,6-naphthalene dicarboxylic acid tetramethylene glycol ester resin, etc.).

Among these, polyethylene terephthalate resin and polybutylene terephthalate resin are preferred, and polybutylene terephthalate resin is particularly preferred.

The amount of terminal carboxyl groups of the thermoplastic polyester resin as long as it does not hinder the present The effects of the invention are not particularly limited. The amount of terminal carboxyl groups of the thermoplastic polyester resin is preferably 30 meq/kg or less, more preferably 25 meq/kg or less.

The intrinsic viscosity (IV) of the thermoplastic polyester resin is not particularly limited insofar as it does not inhibit the effects of the present invention. The intrinsic viscosity of the thermoplastic polyester resin is preferably from 0.60 to 1.30 dL/g. From the viewpoint of preventing cracking or for improving the durability of heating and cooling, it is preferably 0.70 to 1.20 dL/g. When the thermoplastic polyester resin having an intrinsic viscosity in this range is used, the obtained thermoplastic polyester resin composition can be particularly excellent in moldability. In addition, the intrinsic viscosity can also be adjusted by mixing thermoplastic polyester resins of different intrinsic viscosities. For example, a thermoplastic polyester resin having an intrinsic viscosity of 1.0 dL/g and a thermoplastic polyester resin having an intrinsic viscosity of 0.8 dL/g can be mixed to prepare a thermoplastic polyester resin having an intrinsic viscosity of 0.9 dL/g.

The intrinsic viscosity (IV) of the thermoplastic polyester resin can be measured, for example, in o-chlorophenol at a temperature of 35 ° C, and the above values are measured under the conditions.

Further, as the thermoplastic polyester resin, a commercially available product may be used, and a dicarboxylic acid component or a reactive derivative thereof, a diol component or a reactive derivative thereof, and a copolymerizable copolymer may be used. The body is produced by a conventional method such as copolymerization (recondensation) such as transesterification or direct esterification.

[AS resin]

The resin composition of the embodiment of the present invention contains an IR spectrum obtained by IR after melting and heating at 260 ° C for 30 minutes in the air, and the ratio of the peak area of 1573 cm ^{-1 to} the peak area of 1450 cm ^-1 is 2.30%. Hereinafter, the AS resin produced by bulk polymerization is used. This specific AS resin is used for a resin alloyed with the above thermoplastic polyester resin.

In the resin composition of the embodiment, the AS resin is used in a block form. Manufacturer of the manufacturer. Although the reason is not clear, the AS resin produced by bulk polymerization can be reduced in bending more than those produced by a polymerization method other than bulk polymerization.

On the other hand, when only the AS resin produced in the bulk polymerization is used, the discoloration due to heat occurs as described above. Therefore, in the resin composition of the embodiment, in order to control discoloration due to heat, the AS resin produced by bulk polymerization is melt-heated at 260 ° C for 30 minutes in the air, and then IR is measured. In the IR spectrum, the ratio of the peak area of 1573 cm ^{-1 to} the peak area of 1450 cm ^-1 was 2.30% or less of the AS resin. The ratio of the peak area indicates the number of triple chain structures derived from acrylonitrile (hereinafter referred to as "AN"). In other words, in the IR spectrum, the absorption of 1573 cm ^-1 of the three-chain structure based on AN indicates how much the absorption of 1450 cm ^-1 (mainly the absorption of CH-angle vibration) of the entire AS resin-based structure is present. The triple chain structure from AN is less able to reduce the discoloration caused by warming. In addition, although it is not completely relevant, and the reason is not clear, the three-chain structure from the AN is small, and it may be advantageous to reduce the occurrence of bending.

When the ratio of the above-mentioned peak area exceeds 2.30%, discoloration easily occurs due to heat. The ratio of the peak area is preferably 1.50 to 2.20%, more preferably 2.00 to 2.15%.

The ratio of the above-mentioned peak area can be determined by infrared spectroscopy using infrared spectroscopy to determine the infrared absorbance of the AS resin by a Fourier transform type or a wavelength dispersion type infrared spectrometer or a combination of a light source and a detector capable of measuring infrared absorption. . Fig. 1 is an IR spectrum of an AS resin ("AS resin 1" used in Example 1) measured by a micro Fourier transform infrared spectrometer. Then, the ratio of the above-mentioned peak area is calculated by calculating the peak area of 1573 cm ^-1 of the IR spectrum shown in Fig. 1 (having peak absorption near 1573 cm ^-1 , surrounded by the baseline of the bottom before and after the connecting peak and the IR spectrum itself) ratio of the area portion), 1450cm ^-1 to the peak area (having an absorption peak in the vicinity of 1450cm ^-1, to link with the base area of the portion of the IR spectra before and after the bottom peak itself surrounded by) the determined.

The AS resin used in the resin composition of the embodiment is not particularly limited as long as the ratio of the peak area is within a specific range and is produced by bulk polymerization as described above, but the acrylonitrile constituting the AS resin is not particularly limited. The ratio of the total acrylonitrile per unit to the styrene unit (hereinafter referred to as "AN ratio") is preferably from 10 to 50% by mass, more preferably from 20 to 40% by mass.

The AN ratio is determined by the pyrolysis gas chromatographic analysis method of JIS K6231. The area ratio of each peak of acrylonitrile and styrene is determined, and the composition ratio of the polymer is determined to calculate the content of acrylonitrile unit and styrene unit. The value obtained.

Further, in the resin composition of the embodiment, the AS resin may be alloyed with the thermoplastic resin, for example, by melt-kneading using an extruder, but the shape of the AS resin supplied to the extruder is not particularly limited. Granular, powdery, flakes and the like are used, and the average particle diameter thereof can also be appropriately selected.

In the resin composition of the embodiment, the AS resin is preferably 1 to 50 parts by mass, more preferably 2 to 30 parts by mass, more preferably 100 parts by mass, based on 100 parts by mass of the thermoplastic polyester resin. 3 to 10 parts by mass is preferred.

[other ingredients]

The resin composition of the embodiment may have a desired property to be added to the thermoplastic resin and the thermosetting resin, for example, an inorganic filler, in order to impart desired properties in accordance with the purpose, without impairing the effects of the present invention. , stabilizers such as antioxidants, ultraviolet absorbers, and hydrolyzable improvers (for example, epoxy trees) A grease, a charge inhibitor, a flame retardant, a flame retardant, an anti-drip agent, a coloring agent such as a dye or a pigment, a mold release agent, a lubricant, a crystallization accelerator, a crystal nucleating agent, and the like.

The resin composition of the embodiment has a resin temperature of 260 ° C, a mold temperature of 60 ° C, a holding pressure of 60 MPa, and is injection-molded by a side gate to produce a flat plate of 120 mm × 120 mm × 2 mmt, and the flatness is 3.0 mm. The following.

<formed product>

In the molded article of the embodiment of the present invention, the thermoplastic polyester resin composition of the embodiment of the present invention is injection molded. In the molded article, the thermoplastic polyester resin composition of the embodiment of the present invention is formed by injection molding, so that the molded article has little deformation due to heat and deformation. Therefore, it can be used favorably in a rod-shaped, plate-shaped, box-shaped molded article, especially for housing automobiles and motors. The use of the case of the case or the cover of various parts in the electronic equipment and the mechanical field, the use of the mechanism parts such as a lever or a shaft, and the use of a structure such as a switch or a connector.

The method of injection molding is not particularly limited, and a conventional method can be employed.

The molded article according to the embodiment of the present invention can be used in a box shape or a flat plate shape of 10 mm or more in either of the longitudinal direction, the horizontal direction, and the high side, and is preferably a box shape or a flat plate shape having a side of 50 mm or more. It is preferable that the one side is a box shape or a flat plate shape of 100 mm or more. Further, the thickness of the preferred molded article is 0.5 mm or more and 5 mm or less, more preferably 1 mm or more and 3 mm or less, and further preferably 1.5 mm or more and 2 mm or less. The molded article according to the embodiment of the present invention has an advantage of exhibiting excellent dimensional accuracy because the bending is small, particularly in the above shape.

[Examples]

Hereinafter, the embodiment of the present invention will be described in more detail by way of examples. However, the invention is not limited to these.

[Examples 1 to 2, Comparative Examples 1 to 7]

In each of the examples and the comparative examples, the components shown in Table 1 were mixed at the ratios shown in the same table, and then spun using a 30 mm 双 twin-screw extruder (TEX-30 manufactured by Nippon Steel Co., Ltd.) at a tube temperature of 260 ° C. The amount was 15 kg/h, the number of revolutions of the screw was 150 rpm, and the mixture was melt-kneaded to obtain a colloidal particle composed of a thermoplastic polyester resin composition. Next, the obtained pellets were injection-molded at a resin temperature of 260 ° C, a mold temperature of 60 ° C, a holding pressure of 60 MPa, and a side gate of 4 mm x 2 mmt to obtain a flat plate of 120 mm × 120 mm × 2 mmt. The detailed sections of the components to be used are indicated below.

(1) Thermoplastic polyester resin (PBT resin)

. PBT resin: manufactured by WinTech Polymer, DURANEX (registered trademark) (inherent viscosity: 0.68 dL/g, terminal carboxyl group: 24 meq/kg)

(2) AS resin

. AS resin 1: block polymer, AN ratio of 26% by mass, MFR38g/10min, IR area ratio of 2.13, average particle diameter of 3.52mm

. AS resin 2: bulk polymer, AN ratio of 26% by mass, MFR38g/10min, IR area ratio of 2.30, average particle diameter of 3.62 mm

. AS resin 3: bulk polymer, AN ratio of 27% by mass, MFR32g/10min, IR area ratio of 2.42, average particle diameter of 3.39mm

. AS resin 4: suspension polymer, AN ratio of 25% by mass, MFR of 41 g/10 min, IR area ratio of 2.29

. AS resin 5: suspension polymer, AN ratio 23% by mass, MFR 80g/10min, IR area ratio 2.32

. AS resin 6: suspension polymer, AN ratio of 25% by mass, MFRlg/10min, IR area ratio 2.36

. AS resin 7: suspension polymer, AN ratio 30% by mass, MFR 39g/10min, IR area ratio 2.45

. AS resin 8: suspension polymer, AN ratio of 25% by mass, MFR 294 g/10 min, IR area ratio of 2.51

. AS resin 9: suspension polymer, AN ratio 40% by mass, MFR 90g/10min, IR area ratio 313

(3) Glass fiber

Nippon Electric Glass Co., Ltd., product name: T-187

(4) release agent

Riken Vitamine (stock) system, product name: RIKEMAL B-150

(5) Antioxidant BASF Japan (stock) system, product name: IRGANOX1010

In addition, the "AN ratio", "MFR", "IR area ratio", and "average particle diameter" in Table 1 are as follows.

AN ratio: total ratio (% by mass) of acrylonitrile to styrene units of each AS resin, pyrolysis diagram obtained by thermal decomposition gas chromatography according to JIS K6231, from acrylonitrile and styrene The area ratio of each peak, the composition ratio of the polymer was measured, and the value obtained by calculating the content of the acrylonitrile unit and the styrene unit was calculated.

‧MFR: Melt flow rate (g/10min) measured at 220 ° C and a load of 10 kg in accordance with ISO 1133-1

‧IR area ratio: After heating and heating at 260 ° C for 30 minutes in the air, the IR spectrum obtained by IR was measured using a microscopic Fourier transform infrared spectrometer (spectrum one, PerkinElmer Japan), 1573 cm ^-1 The peak area, the ratio of the peak area of 1450 cm ^-1

‧Average particle diameter: median diameter (50% diameter) (mm) of the cumulative particle size distribution of the AS-based resin supplied to the twin-screw extruder in accordance with the dry sieving test method of JIS K0069

<evaluation>

The test piece produced was evaluated for flatness and discoloration.

(1) Flatness

A flat test piece of 120 mm × 120 mm × 2 mmt was formed by a side gate of 4 mm x 2 mmt at a holding pressure of 60 MPa, and air-conditioned at 23 ° C × 50% RH for 24 hours or more, and then the bending was measured. In the measurement of the bending, the measurement was performed at 9 o'clock in an image measuring machine (manufactured by Mitutoyo Instruments Co., Ltd.), and the height difference between the highest point and the lowest point was measured. Those whose height difference between the highest point and the lowest point is 3 mm or less are evaluated as A, and those exceeding 3 mm are evaluated as B. The evaluation results are shown in Table 1.

(2) Discoloration

3.5 g of the AS resin was placed in an aluminum dish, and heat-treated at 240 ° C for 30 minutes in a Gil aging incubator, and the discoloration was visually confirmed, and almost no discoloration was evaluated as A, and only a slight discoloration was confirmed as B, and the discoloration was markedly C, and the discoloration was remarkably D. The evaluation results are shown in Table 1.

[Table 1]

From Table 1, in Examples 1 and 2, good results were obtained for any evaluation of flatness and discoloration, and it was found that both bending and discoloration were small. On the other hand, in Comparative Examples 1 to 7, the evaluation of the flatness and the evaluation of the discoloration did not give good results. In particular, in Comparative Example 1 of the AS resin having an IR peak area ratio of more than 2.30%, although it was produced by bulk polymerization, the evaluation of flatness was good, but the evaluation of discoloration was poor, and it was found that even in the form of bulk polymerization. The AS resin produced does not satisfy the conditions of the IR peak area ratio, and discoloration due to heat occurs.

Further, the relationship between the flatness of the AS ratio (AN ratio) of the AS resin, the relationship between the flatness and the MFR, and the relationship between the flatness and the average particle diameter are shown in FIG. 3, FIG. 4, and FIG. Furthermore, in Fig. 4, the horizontal axis (MI) is MFR. 3, 4, and 5, it is understood that the ratio of the AN of the AS resin to the flatness, the MFR and the flatness of the AS resin, and the average particle diameter and flatness of the AS resin are not related. In short, it is understood that the AS resin produced by bulk polymerization contributes to reducing the flatness of the molded article.

The present invention claims priority to Japanese Patent Application No. 2015-108286, the entire disclosure of which is incorporated herein by reference.

All documents, patent applications, and technical specifications described in the present specification are hereby incorporated by reference in their entirety in the extent of the extent of the extent of

Claims (4)

A thermoplastic polyester resin composition comprising: a thermoplastic polyester resin; and an AS resin, wherein the AS resin is obtained by IR in an air at a temperature of 260 ° C for 30 minutes, and an IR spectrum obtained by IR measurement is 1573 cm ^-1 . The ratio of the peak area to the peak area of 1450 cm ^-1 was 2.30% or less, and was produced by a block polymerization. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition has a resin temperature of 260 ° C, a mold temperature of 60 ° C, a holding pressure of 60 MPa, and a side of 4 mm × 2 mmt. The flatness of the 120 mm × 120 mm × 2 mmt flat plate formed by the gate injection was 3.0 mm or less. A molded article obtained by injection molding a thermoplastic polyester resin composition according to claim 1 or 2. The molded article according to claim 3, wherein either one of the longitudinal direction, the lateral direction, and the height is a box shape or a flat plate shape of 10 mm or more.