JP2017214471A - Method for producing polybutylene terephthalate resin composition molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polybutylene terephthalate resin composition molded article which suppresses transparency and is excellent in appearance.SOLUTION: A method for producing a molded article using a polybutylene terephthalate resin composition includes a step of injection molding the composition under a predetermined molding condition, where the polybutylene terephthalate resin composition contains (A) a polybutylene terephthalate resin and (B) an amorphous resin which conducts a transesterification with the polybutylene terephthalate resin, and (C) a polyvalent-hydroxyl-group-containing compound and contains no transesterification inhibitor, and a molded article has a thin portion with a thickness of 1 mm or less in all or a part thereof.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a molded article of a polybutylene terephthalate resin composition, and more particularly to a method for producing a thin-walled article of a polybutylene terephthalate resin composition.

  Polybutylene terephthalate resin (PBT resin) is excellent in various properties such as mechanical properties, electrical properties, heat resistance, chemical resistance and solvent resistance. Widely used in various applications. In recent years, there has been an increasing demand for smaller and lighter industrial molded products and improved appearance.

  When molding a thin molded product (thin molded product) using a polybutylene terephthalate resin composition (hereinafter also simply referred to as “resin composition”), the fluidity at the time of melting of the resin composition is improved. It is desirable. Examples of the method for improving the fluidity at the time of melting include a method of adding a fluidity improver to the polybutylene terephthalate resin composition.

For example, in Patent Document 1, glycerin and / or a dehydration condensate thereof and a fatty acid having 12 or more carbon atoms are contained in a composition comprising a predetermined amount of polybutylene terephthalate resin (A) and an inorganic filler (B). And a polybutylene terephthalate resin composition comprising a predetermined amount of glycerin fatty acid ester (C) having a hydroxyl value of 200 or more and a hydroxyl value of 200 or more. Patent Document 2 discloses a plate shape having a length in the longitudinal direction twice or more than the length in the short direction, a thickness of 0.7 mm or more and 4 mm or less, and a polybutylene terephthalate resin and a polyethylene terephthalate resin. And a polybutylene terephthalate resin composition having a melt viscosity at a temperature of 260 ° C. and a shear rate of 1000 sec ⁻¹ of 0.10 kPa · s to 0.30 kPa · s, A wind direction control plate formed by injection molding from a gate in the vicinity thereof is described, and this document discloses adding a fatty acid partial ester of a polyhydric alcohol as a fluidity improver.

  Moreover, the appearance of the molded product (surface gloss, low roughness, etc.) and low warpage can be improved by alloying the PBT resin with a low crystalline polyester resin such as polyethylene terephthalate or polycarbonate. In such a resin composition, a transesterification reaction is likely to occur between the PBT resin and the alloy resin, and if the transesterification reaction proceeds too much, the melting point and the crystallization temperature are changed and the expected physical properties cannot be obtained. There is. In particular, in a thin-walled molded product, the transesterification proceeds to inhibit the crystallization of the PBT resin and the resin composition becomes translucent, which may cause a problem since the transparency of the molded product is conspicuous. As a method for suppressing such a transesterification reaction, there is a method of adding a transesterification inhibitor such as a phosphorus stabilizer.

  However, when a transesterification inhibitor is added to the PBT resin composition containing the fluidity improver described above, not only the transesterification reaction between the PBT resin and the alloy resin, but also between the fluidity improver and the PBT resin. The reaction is also suppressed, and there is a problem that the fluidity improving action by the fluidity improving agent is inhibited. Therefore, in the molding of a thin molded product that is required to have a high fluidity that can be filled into a thin part, the composition of the PBT resin composition contains a fluidity improver and does not contain a transesterification inhibitor. May be required.

  Also, from the viewpoint of appearance, the mold surface needs to be firmly transferred to the surface of the molded product, so the resin temperature and mold temperature are set high to increase resin fluidity or solidify in the mold. Need to slow down. Particularly in the molding of thin-walled molded products, the resin temperature and the mold temperature tend to be set high in terms of ensuring fluidity, but such molding conditions are disadvantageous in terms of inhibiting the transesterification reaction. On the other hand, if the molding temperature is lowered in order to suppress the transesterification reaction, it becomes difficult to obtain a thin-walled molded product due to a decrease in fluidity during molding, and the mold transferability is lowered and the appearance is reduced. It tends to be damaged.

International Publication No. 2009/050859 A1 Pamphlet International Publication No. 2013/069519 A1 Pamphlet

As mentioned above, when manufacturing thin-walled molded products using a PBT resin composition using a low crystalline resin as an alloy material, the molded product is made transparent while ensuring high fluidity suitable for molding thin-walled molded products. In addition, there is a problem that it is very difficult to manufacture a molded article that suppresses the appearance and has an excellent appearance.
Accordingly, an object of the present invention is to provide a method for producing a thin-walled molded article of a polybutylene terephthalate resin composition that is suppressed in transparency and excellent in appearance.

[1] One aspect of the present invention is a method for producing a molded article using a polybutylene terephthalate resin composition,
Including a step of performing injection molding under conditions of a cylinder temperature of 260 ° C. or lower and a mold temperature of 100 ° C. or lower,
The polybutylene terephthalate resin composition contains (A) a polybutylene terephthalate resin, (B) an amorphous resin that undergoes a transesterification reaction with the polybutylene terephthalate resin, and (C) a polyhydric hydroxyl group-containing compound, and transesterification Contains no inhibitor,
The mass ratio ((A) / (B)) of (A) polybutylene terephthalate resin and (B) amorphous resin that undergoes a transesterification reaction with polybutylene terephthalate resin is 6.5 / 3.5 to 4.5. /5.5 range,
The molded article relates to a production method having a thin part having a thickness of 1 mm or less in whole or in part.
[2] Another aspect of the present invention is a method for producing a molded article using the polybutylene terephthalate resin composition,
Including a step of performing injection molding under conditions of a cylinder temperature of 270 ° C. or more and a residence time of 10 minutes or less,
The polybutylene terephthalate resin composition contains (A) a polybutylene terephthalate resin, (B) an amorphous resin that undergoes a transesterification reaction with the polybutylene terephthalate resin, and (C) a polyhydric hydroxyl group-containing compound, and transesterification Contains no inhibitor,
The molded article relates to a production method having a thin part having a thickness of 1 mm or less in whole or in part.
[3] In a further aspect of the present invention, the polybutylene terephthalate resin composition further contains (D) an inorganic filler in an amount of 50% by mass or more of the total mass of the composition. The production method according to [2].
[4] In a further aspect of the present invention, (B) an amorphous resin that undergoes a transesterification reaction with a polybutylene terephthalate resin is a polyethylene terephthalate resin, a polycarbonate resin, a polytrimethylene terephthalate resin, and a polycyclohexylene dimethylene terephthalate. The production method according to [1] to [3] above, which contains at least one selected from the group consisting of resins.
[5] A further aspect of the present invention relates to the production method according to the above [1] to [4], wherein (C) the polyhydric hydroxyl group-containing compound contains a fatty acid partial ester of a polyhydric alcohol.

  According to the embodiment of the present invention, it is possible to provide a method for producing a thin molded article of a polybutylene terephthalate resin composition that is suppressed in transparency and excellent in appearance.

  By applying specific molding conditions, the present inventors contain (A) a polybutylene terephthalate resin, (B) an amorphous resin, and (C) a polyhydric hydroxyl group-containing compound, and inhibit transesterification. It has been found that using a polybutylene terephthalate resin composition that does not contain an agent, it is possible to produce a thin-walled molded product that suppresses the transparency of the molded product and is excellent in appearance.

[Polybutylene terephthalate resin composition]
Hereinafter, the details of each component of the polybutylene terephthalate resin composition of the present embodiment will be described by way of examples.

(A) Polybutylene terephthalate resin A polybutylene terephthalate resin (PBT resin) is a dicarboxylic acid component containing at least terephthalic acid or an ester-forming derivative thereof (C _1-6 alkyl ester, acid halide, etc.), and at least carbon atoms. It is a polybutylene terephthalate resin obtained by polycondensation with a glycol component containing an alkylene glycol (1,4-butanediol) of formula 4 or an ester-forming derivative thereof (acetylated product or the like). The polybutylene terephthalate resin is not limited to a homopolybutylene terephthalate resin, and may be a copolymer containing 60 mol% or more (particularly 75 mol% or more and 95 mol% or less) of a butylene terephthalate unit.

  The amount of terminal carboxyl groups of the polybutylene terephthalate resin is not particularly limited as long as the object of the present invention is not impaired. The amount of terminal carboxyl groups of the polybutylene terephthalate resin is preferably 30 meq / kg or less, and more preferably 25 meq / kg or less.

  The intrinsic viscosity of the polybutylene terephthalate resin is not particularly limited as long as the object of the present invention is not impaired. The intrinsic viscosity (IV) of the polybutylene terephthalate resin is preferably 0.60 dL / g or more and 1.2 dL / g or less. More preferably, it is 0.65 dL / g or more and 0.9 dL / g or less. When a polybutylene terephthalate resin having an intrinsic viscosity in such a range is used, the resulting polybutylene terephthalate resin composition has particularly excellent moldability. The intrinsic viscosity can also be adjusted by blending polybutylene terephthalate resins having different intrinsic viscosities. For example, a polybutylene terephthalate resin having an intrinsic viscosity of 0.9 dL / g is prepared by blending a polybutylene terephthalate resin having an intrinsic viscosity of 1.0 dL / g and a polybutylene terephthalate resin having an intrinsic viscosity of 0.7 dL / g. Can do. The intrinsic viscosity (IV) of the polybutylene terephthalate resin can be measured, for example, in o-chlorophenol at a temperature of 35 ° C.

In the preparation of polybutylene terephthalate resin, examples of dicarboxylic acid components (comonomer components) other than terephthalic acid and its ester-forming derivatives include, for example, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-di C _8-14 aromatic dicarboxylic acids such as carboxydiphenyl ether; C _4-16 alkane dicarboxylic acids such as succinic acid, adipic acid, azelaic acid and sebacic acid; C _5-10 cycloalkane dicarboxylic acids such as cyclohexane dicarboxylic acid And ester-forming derivatives of these dicarboxylic acid components (C _1-6 alkyl ester derivatives, acid halides, etc.). These dicarboxylic acid components can be used alone or in combination of two or more.

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

In the preparation of polybutylene terephthalate resin, glycol components (comonomer components) other than 1,4-butanediol include, for example, ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butylene glycol, hexamethylene glycol, neopentyl. C _2-10 alkylene glycol such as glycol and 1,3-octanediol; polyoxyalkylene glycol such as diethylene glycol, triethylene glycol and dipropylene glycol; alicyclic diol such as cyclohexanedimethanol and hydrogenated bisphenol A; bisphenol A, aromatic diols such as 4,4′-dihydroxybiphenyl; 2 mol adduct of bisphenol A ethylene oxide, 3 mol of propylene oxide of bisphenol A An adduct, alkylene oxide adducts of C _2-4 of bisphenol A; or ester-forming derivatives of these glycols (acetylated, etc.). These glycol components can be used alone or in combination of two or more.

Among these glycol components, C _2-6 alkylene glycol such as ethylene glycol and trimethylene glycol, polyoxyalkylene glycol such as diethylene glycol, and alicyclic diol such as cyclohexanedimethanol are more preferable.

Examples of comonomer components that can be used in addition to the dicarboxylic acid component and the glycol component include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 4-carboxy-4′-hydroxybiphenyl. Aromatic hydroxycarboxylic acids; aliphatic hydroxycarboxylic acids such as glycolic acid and hydroxycaproic acid; C _3-12 lactones such as propiolactone, butyrolactone, valerolactone, caprolactone (ε-caprolactone, etc.); esters of these comonomer components And forming derivatives (C _1-6 alkyl ester derivatives, acid halides, acetylated compounds, etc.).

  The content of the polybutylene terephthalate resin is preferably 5 to 80% by mass of the total mass of the resin composition, more preferably 10 to 70% by mass, and further preferably 15 to 60% by mass. .

(B) Amorphous resin By alloying the PBT resin and the amorphous resin, the appearance (surface gloss, low roughness) and low warpage of the molded product can be improved.
On the other hand, when a polyester-based amorphous resin is used as the alloy material, the transesterification reaction between the PBT resin and the amorphous resin tends to proceed, and if the transesterification reaction proceeds excessively, the melting point or crystallization There may be a problem that the desired physical properties cannot be obtained due to the temperature change, and a problem that the transparency of the molded article proceeds. In addition, when a transesterification inhibitor is added to suppress such a transesterification reaction, there is a problem in that the effect of improving fluidity due to the (C) polyvalent hydroxyl group-containing compound described later is hindered. However, according to the study by the present inventors, when the specific molding conditions described later are applied, the alloy contains an amorphous resin that is transesterified with the PBT resin, and an ester for maintaining high fluidity. Even when a resin composition not containing an exchange inhibitor is used, it becomes possible to suppress the transparency of the molded product.

  Examples of the amorphous resin are described below, but the amorphous resin is not limited thereto.

(Polyethylene terephthalate resin)
Polyethylene terephthalate resin (PET resin) is a terephthalic acid or ester-forming derivative thereof (C _1-6 alkyl ester, acid halide, etc.) and ethylene glycol or ester-forming derivative thereof (acetylated product, etc.) It is a polyester resin obtained by polycondensation according to various methods known in the field.

  The polyethylene terephthalate resin may be modified by copolymerizing a small amount of a modifying component that gives a repeating unit other than the terephthaloyl unit and the ethylenedioxy unit within a range not impairing the object of the present invention. The amount of the repeating unit other than the terephthaloyl unit and the ethylenedioxy unit contained in the polyethylene terephthalate resin is preferably less than 4 mol%, more preferably 3 mol% or less, and more preferably 2 mol% or less in all repeating units of the polyethylene terephthalate resin. Is more preferable.

In addition to the polyethylene terephthalate resin, as the amorphous resin, C _2-6 alkylene glycol other than ethylene glycol (for example, trimethylene) may be used instead of the above-mentioned ethylene glycol or its ester-forming derivative (acetylated product). Glycol resins), alicyclic diols (for example, cyclohexanedimethanol, etc.), or polyester resins obtained using these ester-forming derivatives (acetylated products, etc.). Specific examples include polytrimethylene terephthalate resin (PTT resin) and polycyclohexylene dimethylene terephthalate resin (PCT resin), but are not limited thereto.

(Polycarbonate resin)
A polycarbonate resin can also be preferably used as the amorphous resin. Examples of the polycarbonate resin include a polymer obtained by a reaction between a dihydroxy compound and a carbonate such as phosgene or diphenyl carbonate.

  Examples of the dihydroxy compound include alicyclic compounds (for example, alicyclic diols) and bisphenol compounds, with bisphenol compounds being preferred.

Examples of the bisphenol compound include bis (4-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 1,1-bis (4-hydroxy- 3-methylphenyl) ethane, 1,1-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 2,2-bis (4-hydroxy-3-methyl) Phenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3-ethylphenyl) propane, 2,2-bis (4-hydroxy-) 3-t-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4- Droxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) hexane, 2, 2-bis (4-hydroxyphenyl-4-methylpentane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4- Hydroxyphenyl) dibenzylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylpropane, 2,2,2 ′, 2′-tetrahydro3,3,3 ′, 3′-tetramethyl-1, 1'-spirobi - [1H-indene] -6,6'-bis _{(hydroxyaryl)} such as a diol _{C 1-10} alkane, preferably The bis _{(hydroxyaryl) C 1-6} alkanes; 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) bis cyclohexane _{(hydroxyaryl) C 4-10} cycloalkyl Alkanes; 4,4′-dihydroxydiphenyl ether, dihydroxyaryl ethers such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether; 4,4′-dihydroxydiphenylsulfone, 4,4′-dihydroxy-3,3 Dihydroxyaryl sulfones such as'-dimethyldiphenylsulfone; dihydroxyarylsulfides such as 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfide;4,4'-dihydroxydiphenylsulfone Koxide, 4 Dihydroxyaryl sulfoxides such as 4′-dihydroxy-3,3′-dimethyldiphenyl sulfoxide; dihydroxys such as 4,4′-dihydroxydiphenyl ketone and 4,4′-dihydroxy-3,3′-dimethyldiphenyl ketone; Examples include aryl ketones.

  Preferred polycarbonate resins include bisphenol A type polycarbonate.

  The polycarbonate resin may be a homopolycarbonate or a copolycarbonate.

  An amorphous resin may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the amorphous resin is such that the ratio of (A) PBT resin to (B) amorphous resin ((A) PBT resin / (B) amorphous resin (mass ratio)) is 8 / 2-3. It is preferably used in an amount of / 7. (A) PBT resin / (B) amorphous resin (mass ratio) is more preferably in the range of 7/3 to 4/6, and 6.5 / 3.5 to 4.5 / 5.5. Is more preferably in the range of 6/4 to 5/5. When (A) PBT resin / (B) amorphous resin (mass ratio) is within the above range, it is preferable from the viewpoint of improving the molding cycle and surface appearance. Further, (A) PBT resin / (B) amorphous resin (mass ratio) is in the range of 6.5 / 3.5 to 4.5 / 5.5, more preferably 6/4 to 5/5. Even when relatively low-temperature molding conditions are applied, excellent appearance can be obtained.

(C) Polyhydric hydroxyl group-containing compound The polyvalent hydroxyl group-containing compound is a compound having two or more hydroxyl groups in one molecule.

  By adding the polyvalent hydroxyl group-containing compound, the fluidity of the polybutylene terephthalate resin composition can be enhanced. Usually, if a component that enhances the fluidity is added to the polybutylene terephthalate resin, even if the fluidity can be improved, the deterioration of the properties such as mechanical strength and toughness of the polybutylene terephthalate resin itself cannot be avoided. However, by using the polyhydric hydroxyl group-containing compound, the fluidity at the time of melting of the polybutylene terephthalate resin composition can be efficiently improved while maintaining the characteristics of the polybutylene terephthalate resin at a high level. In particular, this embodiment is preferable in that high fluidity capable of filling a thin portion is obtained.

  As the polyvalent hydroxyl group-containing compound, those produced by various methods known in the art may be used, or commercially available products may be purchased and used.

  The polyhydric hydroxyl group-containing compound is preferably a partial ester of a polyhydric alcohol and a fatty acid. The fatty acid partial ester of polyhydric alcohol includes polyhydric alcohol such as ethylene glycol, propylene glycol, glycerin, polyglycerin, pentaerythritol, caprylic acid, capric acid, lauric acid, myristic acid, oleic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, arachidic acid, behenic acid, montanic acid and the like, usually a saturated fatty acid having 7 to 32 carbon atoms, or decenoic acid, undecenoic acid, dodecenoic acid, tetradecenoic acid, oleic acid, erucic acid, Preference is given to partial esters with unsaturated fatty acids such as linoleic acid, linolenic acid, ricinoleic acid and the like.

  From the viewpoint of improving the fluidity at the time of melting the polybutylene terephthalate resin composition, and from the viewpoint of suppressing deterioration of various properties inherent in the polybutylene terephthalate resin, a glycerin fatty acid ester or diglycerin is used as the polyvalent hydroxyl group-containing compound. It is more preferable to use an ether obtained by addition polymerization of alkylene oxide. Hereinafter, ethers obtained by addition polymerization of alkylene oxide to glycerin fatty acid ester and diglycerin will be described.

  The glycerin fatty acid ester is an ester composed of glycerin and / or a dehydration condensate thereof and a fatty acid. Among glycerin fatty acid esters, those obtained using fatty acids having 12 or more carbon atoms are preferred. Examples of the fatty acid having 12 or more carbon atoms include lauric acid, oleic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, behenic acid, and the like. Fatty acids having 12 to 32 carbon atoms are preferred, and fatty acids having 12 to 22 carbon atoms are particularly preferred. Specifically, lauric acid, stearic acid, 12-hydroxystearic acid or behenic acid is particularly preferable. It is preferable to use a fatty acid having 12 or more carbon atoms because the heat resistance of the resin tends to be sufficiently maintained. A carbon number of 32 or less is preferable because the effect of improving fluidity can be further enhanced.

  Examples of preferred glycerin fatty acid esters include glycerin monostearate, glycerin monobehenate, diglycerin monostearate, triglycerin monostearate, triglycerin stearic acid partial ester, tetraglycerin stearic acid partial ester, decaglycerin lauric acid partial ester Glycerin mono-12-hydroxystearate and the like.

  The ether obtained by addition polymerization of alkylene oxide to diglycerin is obtained by, for example, polyoxypropylene diglyceryl ether obtained by addition polymerization of propylene oxide to diglycerin or addition polymerization of ethylene oxide to diglycerin. Polyoxyethylene diglyceryl ether is mentioned. Among these, use of polyoxyethylene diglyceryl ether is particularly preferable.

  The polyhydric hydroxyl group-containing compound preferably has a hydroxyl value of 200 or more and 1000 or less as measured in accordance with Oil Chemical Society method 2,4,9,2-71 hydroxyl value (pyridine / acetic anhydride method). If the said hydroxyl value is 200 or more, it exists in the tendency for the effect of a fluid improvement to increase more. In addition, from the viewpoint of maintaining good mechanical properties, heat resistance, and chemical resistance by suppressing the decrease in the molecular weight of polybutylene terephthalate resin due to excessive reaction between fatty acid partial ester of polyhydric alcohol and polybutylene terephthalate. Is preferably 1000 or less. The hydroxyl value is more preferably 250 or more, and more preferably 500 or less.

  (C) The content of the polyhydric hydroxyl group-containing compound is preferably 0.05 to 5 parts by mass with respect to 100 parts by mass in total of the contents of (A) PBT resin and (B) amorphous resin. More preferably, it is 0.1-3 mass parts, More preferably, it is 0.5-2 mass parts. If the content of the polyvalent hydroxyl group-containing compound is 0.05 parts by mass or more, the effect of improving the fluidity tends to be obtained sufficiently, and if it is 5 parts by mass or less, molding by gas generation during molding is preferable. This is preferable from the viewpoint of suppressing appearance defects and mold contamination.

(D) Inorganic filler In addition to (A) PBT resin, (B) amorphous resin, and (C) polyhydric hydroxyl group-containing compound, the polybutylene terephthalate resin composition of the present embodiment includes (D) An inorganic filler can be contained.

  By adding an inorganic filler, the mechanical properties of the molded product can be improved. In particular, in the present embodiment, the mechanical strength can be further improved by adding an inorganic filler, which is preferable from the viewpoint of improving the rigidity of a thin molded product.

  As the inorganic filler, for example, glass fiber can be preferably used. The fiber diameter, fiber length, shape of glass fiber, glass cutting method such as chopped strands and roving are not particularly limited. For example, the fiber length is 0.5 to 10.0 mm, preferably 2.0 to 6.0 mm, and the fiber diameter is 1.0 to 30.0 μm, preferably 9.0 to 14.0 μm. Examples of the shape include a cylindrical cross section, a saddle-shaped cross section, and an oval cross section. Moreover, although the kind of glass is not limited, E glass and the corrosion resistant glass which contains a zirconium element in a composition are used preferably on quality.

  In addition, for the purpose of improving the interfacial characteristics between the glass fiber and the resin matrix, glass fiber surface-treated with an organic treatment agent such as an aminosilane compound or an epoxy compound can be preferably used, and the amount of the organic treatment agent indicated by the heat loss value More preferably, the glass fiber is 1% by mass or more.

  Moreover, it can replace with the above-mentioned glass fiber and can also use inorganic fillers other than glass fiber in combination with glass fiber. Examples of inorganic fillers other than glass fibers include fibrous fillers other than glass fibers, granular fillers, and plate-like fillers.

  As fibrous fillers other than glass fiber, asbestos fiber, silica fiber, silica-alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, stainless steel, aluminum, titanium Examples thereof include metal fibrous materials such as copper and brass. In addition, as the granular filler, silica, quartz powder, glass beads, milled glass fiber, glass balloon, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, wollastonite and other silicates, oxidation Metal oxides such as iron, titanium oxide, zinc oxide, antimony trioxide and alumina, carbonates of metals such as calcium carbonate and magnesium carbonate, sulfates of metals such as calcium sulfate and barium sulfate, other ferrites, silicon carbide, Examples thereof include silicon nitride, boron nitride and various metal powders. Moreover, as a plate-shaped filler, mica, glass flakes, various metal foils, etc. can be illustrated.

  (D) When it contains an inorganic filler, the content is not particularly limited, but it is 50 to 200 parts by mass with respect to a total of 100 parts by mass of (A) PBT resin and (B) amorphous resin. It is preferable that it is 80-140 mass parts, More preferably, it is 90-130 mass parts. If the content of the inorganic filler is 50 parts by mass or more, it is preferable from the viewpoint of improving the mechanical strength of the molded product, and if it is 200 parts by mass or less, it is preferable from the viewpoint of fluidity during molding.

  In addition, it is common to add a transesterification inhibitor to the composition containing the PBT resin and the amorphous resin as described above for the purpose of suppressing the reaction between the PBT resin and the amorphous resin. . However, in this embodiment, in order to maintain the fluidity improvement effect of the polyvalent hydroxyl group-containing compound and ensure fluidity suitable for molding a thin molded article, it is preferable that the transesterification inhibitor is substantially not contained. . In the present specification, the phrase “substantially containing no transesterification inhibitor” means that the transesterification inhibitor content is 100 parts by mass in total of the contents of (A) PBT resin and (B) amorphous resin. On the other hand, it means that it is 1 part by mass or less, more preferably 0.5 part by mass or less, and particularly preferably not at all.

  In addition, examples of the transesterification inhibitor in the present specification include phosphorus stabilizers such as organic phosphite compounds, phosphonite compounds, and metal phosphates. Specific examples include bis (2,4-di-t-4methylphenyl) pentaerythritol diphosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, tetrakis (2,4 Examples of the -di-t-butylphenyl) -4,4'-biphenylene phosphonite and metal phosphate include monobasic calcium phosphate, monobasic sodium phosphate hydrate, and the like.

[Other ingredients]
The polybutylene terephthalate resin composition of this embodiment can contain other components other than the above-mentioned (A)-(D) as needed. Other components include, for example, mold release agents, antioxidants, heat stabilizers, molecular weight modifiers, ultraviolet absorbers, antistatic agents, dyes, pigments, lubricants, crystallization accelerators, crystal nucleating agents, near infrared rays. Examples include, but are not limited to, absorbents, flame retardants, flame retardant aids, and organic fillers.

[Resin composition]
The polybutylene terephthalate resin composition of this embodiment is excellent in fluidity at the time of melting. The fluidity of the resin composition is preferably in a range where the thin portion can be filled at the cylinder temperature during molding. Specifically, in accordance with ISO11443, the melt viscosity measured at a furnace temperature of 260 ° C., a capillary φ1 mm × 20 mmL, and a shear rate of 1000 sec ⁻¹ is preferably 300 Pa · s or less, and preferably 270 Pa · s or less. More preferably, it is more preferably 250 Pa · s or less, and particularly preferably less than 250 Pa · s.

  The form of the polybutylene terephthalate resin composition of the present embodiment may be a powder mixture or a molten mixture (melt kneaded material) such as pellets. The manufacturing method of the polybutylene terephthalate resin composition of this embodiment is not specifically limited, It can manufacture using the installation and method known in the said technical field. For example, necessary components can be mixed and kneaded using a single or twin screw extruder or other melt kneader to prepare pellets for molding. A plurality of extruders or other melt kneaders may be used. Moreover, all the components may be charged simultaneously from the hopper, or some components may be charged from the side feed port.

[Production method of molded products]
One aspect of the present invention relates to a method for producing a molded article using the polybutylene terephthalate resin composition described above.
The inventors of the present invention use the above-described polybutylene terephthalate resin composition and apply the following specific molding conditions to produce a thin molded product having excellent appearance while suppressing the transparency of the molded product. Found that you can.

(Embodiment 1)
The method for producing a molded product according to the present embodiment uses the above-described polybutylene terephthalate resin composition as a ratio of (A) PBT resin and (B) amorphous resin ((A) PBT resin / (B) amorphous system. Resin (mass ratio) is a PBT resin composition having a range of 6.5 / 3.5 to 4.5 / 5.5, a cylinder temperature of 260 ° C. or lower, and a mold temperature of 100 ° C. or lower. And injection molding.

  In the case of molding a molded article excellent in appearance, particularly a thin-walled molded article, it is usually desirable to set the cylinder temperature and the mold temperature to high temperature conditions. Contrary to this expectation, according to the manufacturing method of the present embodiment, when the ratio of (A) PBT resin and (B) amorphous resin is within the specific range, the cylinder temperature is 260 ° C. or less, and Under a relatively low temperature condition of a mold temperature of 100 ° C. or lower, a molded product having excellent appearance can be produced. Moreover, since it is a low temperature condition, the transesterification reaction of PBT resin and amorphous resin can be suppressed. For this reason, even when a resin composition that does not contain a transesterification inhibitor is used to ensure high fluidity, the transparency of the molded product can be suppressed, which is particularly advantageous for molding a thin-walled molded product. . Furthermore, decomposition of the resin composition at the time of molding can be suppressed, and there is an advantage that a molded product excellent in mechanical properties (tensile strength) can be easily obtained.

  (A) PBT resin / (B) amorphous resin (mass ratio) is more preferably in the range of 6/4 to 5/5. The cylinder temperature is more preferably 255 ° C. or less, further preferably 250 ° C. or less, further preferably 245 ° C. or less, and particularly preferably 240 ° C. or less. The lower limit of the cylinder temperature is preferably 230 ° C. or higher and more preferably 235 ° C. or higher in consideration of workability. The mold temperature is more preferably 95 ° C. or less, and further preferably 90 ° C. or less. The lower limit of the mold temperature is usually preferably 50 ° C. or higher.

(Embodiment 2)
The method for producing a molded product according to this embodiment is characterized in that injection molding is performed under conditions of a cylinder temperature of 270 ° C. or more and a residence time of 10 minutes or less.
According to the manufacturing method of the present embodiment, the transesterification reaction between the PBT resin and the amorphous resin is suppressed by setting the residence time to 10 minutes or less even under a relatively high temperature condition of 270 ° C. or higher. Is possible. In addition, when the residence time is within the above range, decomposition of the resin composition during molding is suppressed, and a molded product having excellent mechanical properties (tensile strength) is easily obtained.

  The cylinder temperature is more preferably 275 ° C. or more from the viewpoint of improving the appearance, more preferably 280 ° C. or more, and 300 ° C. or less from the viewpoint of decomposition of the resin composition and suppression of transparency of the molded product. Is preferable, and it is more preferable that it is 290 degrees C or less. The residence time is more preferably 5 minutes or less. In the present specification, the residence time is the time from when the resin composition is supplied into the cylinder of the molding machine until it is injected into the mold through plasticization and kneading.

  The molding method is not particularly limited as long as the injection molding conditions described in the first embodiment and the second embodiment can be satisfied, and various molding methods and molding machines known in the technical field can be applied. it can.

  According to the method for manufacturing a molded product of the present embodiment, it is possible to manufacture a thin molded product that is suppressed in transparency and excellent in appearance. In the present specification, the thin molded article means a molded article having a thin portion having a thickness of 1 mm or less in at least a part of the molded article. The thickness of the thin portion may be appropriately set according to the application of the molded product, but may be, for example, 0.9 mm or less, and may be 0.8 mm or less. Although a minimum is not specifically limited, Usually, it is 0.2 mm or more.

  Such a thin molded article can be suitably used for applications such as connectors, switches, capacitors, integrated circuits (ICs), relays, resistors, light emitting diodes (LEDs), coil bobbins and their peripheral devices or housings.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Details of the components used are as follows.
(A) Polybutylene terephthalate resin Polybutylene terephthalate (Wintech Polymer Co., Ltd., IV = 0.7 dL / g)
(B) Amorphous resin Polyethylene terephthalate (Teijin Limited, IV = 0.7 dL / g)
(C) Polyhydric hydroxyl group-containing compound Glycerin mono-12 hydroxystearate (manufactured by Riken Vitamin Co., Ltd., hydroxyl value 420)
(D) Inorganic filler-Glass fiber (NEC Electric Glass Co., Ltd., ECS03T-187)
・ Transesterification inhibitor (manufactured by Taihei Chemical Sangyo Co., Ltd., monocalcium phosphate)
The hydroxyl value is a value measured by the Oil Chemistry Association method 2, 4, 9, 2-71 hydroxyl value (pyridine / acetic anhydride method).

(Resin compositions 1 to 12)
The components shown in Table 1 are dry blended with the composition (parts by mass) shown in Table 1, and supplied from a hopper to a twin-screw extruder having a 30 mmφ screw (manufactured by Nippon Steel Works) and melt-kneaded at 260 ° C. The pellet-shaped resin compositions 1-12 were obtained.

<Evaluation of transparency control>
1. The obtained pellet-shaped resin composition 1 was injection-molded at a mold temperature of 80 ° C. and a cylinder temperature and a residence time shown in Table 2, and a strip-shaped test having a long side of 130 mm, a short side of 13 mm, and a thickness of 0.8 mm. A piece (filled from a 130 mm × 0.75 mm film gate provided on one side of the long side) was produced. The produced test piece was visually observed to evaluate the transparency of the molded product. The results are shown in Table 2.
2. The obtained pellet-shaped resin compositions 1 to 12 were injection-molded under the molding conditions shown in Table 3 to produce strip-shaped test pieces having a long side of 130 mm, a short side of 13 mm, and a thickness of 0.8 mm as described above. did. The produced test piece was visually observed to evaluate the transparency of the molded product. The results are shown in Table 3.
The evaluation criteria are as follows. If it is “Δ” or more, it is suitable for practical use as a thin molded product.
○: Transparency did not occur △: Slightly translucent ×: Translucent

<Melt viscosity>
About the obtained pellet-shaped resin compositions 1-12, melt viscosity was measured on conditions of a furnace body temperature of 260 ° C., a capillary diameter of 1 mm × 20 mmL, and a shear rate of 1000 sec ⁻¹ using Capillograph 1B (manufactured by Toyo Seiki Seisakusho). did. The results are shown in Table 3.
The evaluation criteria are as follows. If it is “◯” or more, it is suitable for filling a thin portion.
○: Less than 250 Pa · s ×: 250 Pa · s or more

<Evaluation of glossiness>
The obtained pellet-shaped resin compositions 1 to 12 were blended with a master batch obtained by adding 10% by mass of carbon black to PBT resin at a mass ratio of 19: 1 under the molding conditions shown in Table 3. In the same manner as in the evaluation of suppression of transparency, a strip-shaped test piece having a long side of 130 mm, a short side of 13 mm, and a thickness of 0.8 mm was produced. Using the produced test piece, the glossiness at an incident angle of 60 ° was measured by a portable gloss meter (“HG-246” manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS Z8741. The results are shown in Table 3.
◎: Glossiness is 70% or more ○: Glossiness is 60% or more and less than 70% ×: Glossiness is less than 60%

<Evaluation of tensile strength>
The obtained pellet-shaped resin composition 1 was injection-molded at a mold temperature of 80 ° C. at the cylinder temperature and residence time shown in Table 4 to prepare test pieces specified in ISO 3167, and in accordance with ISO 527-1 The tensile strength was evaluated. The results are shown in Table 4.
A: Tensile strength is 150 MPa or more B: Tensile strength is 110 MPa or more and less than 150 MPa X: Tensile strength is less than 110 MPa

  From the above results, a PBT resin composition containing a PBT resin, an amorphous resin, and a polyhydric hydroxyl group-containing compound, containing no transesterification inhibitor, and having a high melt viscosity suitable for molding a thin-walled molded product. In the above, it was shown that by applying specific molding conditions, it is possible to suppress the transparency of the molded product and to mold a thin molded product excellent in appearance.

Claims (5)

A method for producing a molded article using a polybutylene terephthalate resin composition,
Including a step of performing injection molding under conditions of a cylinder temperature of 260 ° C. or lower and a mold temperature of 100 ° C. or lower,
The polybutylene terephthalate resin composition contains (A) a polybutylene terephthalate resin, (B) an amorphous resin that undergoes a transesterification reaction with the polybutylene terephthalate resin, and (C) a polyhydric hydroxyl group-containing compound, and transesterification Contains no inhibitor,
The mass ratio ((A) / (B)) of (A) polybutylene terephthalate resin and (B) amorphous resin that undergoes a transesterification reaction with polybutylene terephthalate resin is 6.5 / 3.5 to 4.5. /5.5 range,
The molded product has a thin portion having a thickness of 1 mm or less in whole or in part. A method for producing a molded article using a polybutylene terephthalate resin composition,
Including a step of performing injection molding under conditions of a cylinder temperature of 270 ° C. or more and a residence time of 10 minutes or less,
The polybutylene terephthalate resin composition contains (A) a polybutylene terephthalate resin, (B) an amorphous resin that undergoes a transesterification reaction with the polybutylene terephthalate resin, and (C) a polyhydric hydroxyl group-containing compound, and transesterification Contains no inhibitor,
The molded product has a thin portion having a thickness of 1 mm or less in whole or in part.   The production method according to claim 1 or 2, wherein the polybutylene terephthalate resin composition further contains (D) an inorganic filler in an amount of 50% by mass or more of the total mass of the composition.   (B) The amorphous resin that undergoes a transesterification reaction with the polybutylene terephthalate resin contains at least one selected from the group consisting of a polyethylene terephthalate resin, a polycarbonate resin, a polytrimethylene terephthalate resin, and a polycyclohexylene dimethylene terephthalate resin. The manufacturing method according to any one of claims 1 to 3.   (C) The manufacturing method of any one of Claims 1-4 in which a polyhydric-hydroxyl group containing compound contains the fatty-acid partial ester of a polyhydric alcohol.