JP2007277515A - Polyester resin composition and polyester molded body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molded body which has good impact resistance and high heat conductivity, and to provide a resin composition suitable for obtaining the molded body which has good moldability. <P>SOLUTION: The polyester resin composition is characterized by containing a dicarboxylic acid component (a) comprising an aromatic dicarboxylic acid unit (a1) as a main component and a glycol component (b) comprising a tetramethylene glycol unit (b1) as a main component and by containing 50-99.7 parts by mass of the polyester resin (A) of which the intrinsic viscosity at 25°C is in a range of 0.9-1.5 dl/g when it is dissolved in a mixed solution of phenol/1,1,2,2-tetrachloroethane=1/1 (mass ratio) and 0.3-50 parts by mass of a metal (B) containing tin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polyester resin composition and a polyester molded body, and more particularly to a heat dissipating material having high thermal conductivity.

Polyester resins typified by polybutylene terephthalate are excellent in various physical properties, and are therefore used in a wide range of applications such as molded articles, packaging films, and fibers. Among them, the mechanical properties such as heat resistance, rigidity, and impact resistance are particularly excellent, so the use of polyester resin moldings is promising in the automotive field and the home appliance field. Widely adopted.
In these fields of automobiles and home appliances, downsizing, weight reduction, and fine electronic control are being promoted due to various demands, but this causes problems that the heat storage of electronic parts affects the life of products. ing.

  The current mainstream technology for solving this heat storage problem is a heat dissipation technology using a metal heat sink using a metal substrate such as aluminum or copper, but there are many limitations in terms of downsizing, weight reduction, and design. There is. Therefore, it is conceivable to use a resin that is easy to reduce in size and weight and has a high degree of design freedom. However, since the resin generally has low heat dissipation, it cannot be used as it is for these members. Thus, as a method for improving the heat dissipation of the resin, a method of adding an inorganic filler to the polyphenylene sulfide resin is known (see, for example, Patent Document 1). As a further improvement, a tin-based low melting point having high thermal conductivity. There are techniques that use metals, graphite, carbon fibers, carbon nanotubes, and the like together (for example, see Patent Documents 2 to 4).

However, since the polyphenylene sulfide resin has a melting point of about 280 ° C. and a molding temperature close to 300 ° C., a high heat dissipation material with other resins is desired from the viewpoint of resin cost, moldability, and production cost. Thus, a highly heat-dissipating material using polybutylene terephthalate resin having a good moldability and physical property balance is desired.
By the way, a highly conductive resin composition containing a tin-based low melting point metal (so-called solder or lead-free solder) in polybutylene terephthalate resin is disclosed (for example, see Patent Documents 5 and 6).

However, when the polybutylene terephthalate resin composition described in Patent Document 5 and Patent Document 6 is molded, cracks are formed at the time of molding in spite of the use of a polybutylene terephthalate resin that is originally excellent in moldability and physical property balance. There was a problem that it was easy to occur and productivity became low. Further, the obtained molded body also has a problem that it has low impact resistance and is brittle.
JP 2001-151905 A JP 2003-49081 A JP 2004-339290 A WO03 / 029352 international pamphlet JP-A-10-237331 JP 2001-200163 A

  The present invention is to provide a molded article having good impact resistance and high thermal conductivity, and is a resin composition suitable for obtaining such a molded article, which is a resin composition having good moldability. Is to provide.

  The present invention contains a dicarboxylic acid component (a) whose main component is an aromatic dicarboxylic acid unit (a1) and a glycol component (b) whose main component is a tetramethylene glycol unit (b1), Intrinsic viscosity at 25 ° C. when dissolved in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 1/1 (mass ratio) is in the range of 0.9 to 1.5 dl / g. A polyester resin composition obtained by melt-kneading 50 to 99.9 parts by mass of a certain polyester resin (A) and 0.1 to 50 parts by mass of a metal (B) containing tin (however, the component (A) and the component ( The total of B) relates to 100 parts by mass), and relates to a polyester molded body formed by molding this polyester resin composition.

  The polyester resin composition of the present invention has good moldability, and the polyester molded product obtained by molding the polyester resin composition of the present invention has high thermal conductivity and excellent impact resistance.

The polyester resin composition of the present invention is obtained by melt-kneading a polyester resin (A) and a metal (B) containing tin.
The polyester resin (A) contains a dicarboxylic acid component (a) whose main component is an aromatic dicarboxylic acid unit (a1) and a glycol component (b) whose main component is a tetramethylene glycol unit (b1).
The aromatic dicarboxylic acid unit (a1) is a unit derived from an aromatic dicarboxylic acid or an ester thereof, and forms a main component in the dicarboxylic acid component (a). Here, a main component is a component which occupies 50 mol% or more when the sum total of all the dicarboxylic acid components of a polyester resin (A) is 100 mol%.

  Although content in particular of an aromatic dicarboxylic acid unit (a1) is not restrict | limited, 80 mol% or more is preferable in all the dicarboxylic acid components of a polyester resin (A). When the content of the aromatic dicarboxylic acid unit (a1) is 80 mol% or more, mechanical strength and heat resistance tend to be good. The lower limit of the content of the aromatic dicarboxylic acid unit is more preferably 85 mol% or more, and particularly preferably 90 mol% or more.

  The aromatic dicarboxylic acid unit (a1) is not particularly limited. For example, a benzene ring or a naphthalene ring such as terephthalic acid, isophthalic acid, 1,5- or 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, etc. And aromatic dicarboxylic acids having two carboxy groups directly, or ester-forming derivatives thereof (lower alkyl esters such as methyl, ethyl and propyl, phenyl esters and the like).

  In these, a terephthalic acid unit is preferable and it is preferable to contain 80 mol% or more in all the dicarboxylic acid components of a polyester resin (A). When the content of the terephthalic acid unit is 80 mol% or more, the mechanical strength and heat resistance tend to be good. The lower limit of the content of the terephthalic acid unit is more preferably 85 mol% or more, and particularly preferably 90 mol% or more. The upper limit of the content of the terephthalic acid unit is not particularly limited, but is preferably 99.9 mol% or less when used in combination with a 2,6-naphthalenedicarboxylic acid unit described later. In this case, the upper limit of the content of the terephthalic acid unit is more preferably 99 mol% or less, and particularly preferably 97 mol% or less.

  In addition, 2,6-naphthalenedicarboxylic acid units are preferable from the viewpoint of polymer deterioration described later. Although content in particular of a 2, 6- naphthalene dicarboxylic acid unit is not restrict | limited, 0.1-10 mol% is preferable in all the dicarboxylic acid components of a polyester resin (A). When the content of 2,6-naphthalenedicarboxylic acid units is 0.1 mol% or more, the deterioration of the resin tends to be suppressed, and when it is 10 mol% or less, the heat resistance tends to be good. The lower limit of the content of 2,6-naphthalenedicarboxylic acid units is more preferably 1 mol% or more, and particularly preferably 3 mol% or more. Further, the upper limit of the content of 2,6-naphthalenedicarboxylic acid units is more preferably 9 mol% or less, and particularly preferably 7 mol% or less.

The dicarboxylic acid unit other than the aromatic dicarboxylic acid unit (a1) is not particularly limited, and examples thereof include aliphatic dicarboxylic acid units (a2) such as adipic acid, sebacic acid, oxalic acid, and succinic acid.
Although content in particular of an aliphatic dicarboxylic acid unit (a2) is not restrict | limited, 10 mol% or less is preferable in all the dicarboxylic acid components of a polyester resin (A). When the content of the aliphatic dicarboxylic acid unit is 10 mol% or less, the heat resistance tends to be good.

The tetramethylene glycol unit (b1) is a unit derived from tetramethylene glycol and forms a main component in the glycol component (b). Here, a main component is a component which occupies 50 mol% or more when all the glycol components are 100 mol%.
As for content of a tetramethylene glycol unit (b1), 60 mol% or more is preferable in all the glycol components of a polyester resin (A). When the content of the tetramethylene glycol unit (b1) is 60 mol% or more, the thermal stability tends to be good.

  The glycol component (b) other than the tetramethylene glycol unit (b1) is not particularly limited. For example, an alkylene glycol having 2 to 6 carbon atoms such as ethylene glycol, trimethylene glycol, propylene glycol, Examples include diethylene glycol, triethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, bisphenol A ethylene oxide adduct, and bisphenol S ethylene oxide adduct. One or more of these glycols can be used as long as the physical properties are not significantly changed.

The polyester resin (A) preferably contains an antioxidant from the viewpoint of the stability of the polymerization reaction. The antioxidant is not particularly limited, and examples thereof include tetrakis (methylene-3- (dodecylthio) propionate) methane, tetrakis (methylene (3,5-t-butyl-4-hydroxyhydrocinnamate)). Methane, tridecyl phosphate, tris (2,4-dibutylphenyl) phosphite, tetrakis (methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate) Methane etc. are mentioned, These can be used individually or in combination of 2 or more types. Among them, tetrakis (methylene (3,5-t-butyl-4-hydroxyhydrocinnamate)) methane, tridecyl phosphate, tetrakis (methylene-3- (3,5′-di-t-butyl) -4'-hydroxyphenyl) propionate) methane is preferred.
Although content in particular of an antioxidant is not restrict | limited, 0.03-2 mass% is preferable in a polyester resin (A).

When the polyester resin (A) is dissolved in a phenol / 1,1,2,2-tetrachloroethane = 1/1 (mass ratio) mixed solvent, the intrinsic viscosity at 25 ° C. is 0.9 to 1. The range is 5 dl / g.
In the present invention, it is particularly important that the intrinsic viscosity of the polyester resin (A) is in this range. The metal (B) containing tin described later is a component that imparts thermal conductivity to the polyester resin composition, but the polyester resin (A) and the metal (B) containing tin are melt-kneaded to form a polyester resin. When the composition is obtained, the polyester resin (A) is decomposed by the metal (B) containing the gift, and the intrinsic viscosity of the polyester resin in the resulting polyester resin composition is the polyester resin before melt-kneading. The present inventors have found that it becomes lower than (A) (polymer degradation). Therefore, in order to express the physical properties of the polyester molded body, particularly impact resistance, it is necessary to make the intrinsic viscosity of the polyester resin (A) before melt kneading within a specific range.
When the intrinsic viscosity of the polyester resin (A) is 0.9 dl / g or more, the impact resistance of the polyester molded product tends to be good, and when it is 1.5 dl / g or less, the moldability of the polyester resin composition is high. It tends to be good. The lower limit of the intrinsic viscosity of the polyester resin (A) is preferably 0.95 dl / g or more, more preferably 1 dl / g or more, further preferably 1.05 dl / g or more, and particularly preferably 1.1 dl / g or more. The upper limit of the intrinsic viscosity of the polyester resin (A) is preferably 1.45 dl / g or less, and particularly preferably 1.4 dl / g or less.

  Content of a polyester resin (A) is 50-99.9 mass parts when the sum total with the metal (B) containing the tin mentioned later is 100 mass parts. When the content of the polyester resin (A) is 50 parts by mass or more, moldability and physical property balance tend to be good, and when it is 99.9 parts by mass or less, thermal conductivity tends to be good. 65 mass parts or more are preferable, as for the lower limit of content of a polyester resin (A), 70 mass parts is more preferable, and 75 mass parts or more is especially preferable. Moreover, 98 mass parts or less are preferable, as for the upper limit of content of a polyester resin (A), 95 mass parts or less are more preferable, and 90 mass parts or less are especially preferable.

The polyester resin (A) can be produced by a known transesterification method or an esterification polymerization method. In the transesterification method, the total glycol component such as tetramethylene glycol is 1.2 to 1.6 times in molar ratio to the total acid component such as terephthalic acid ester and 2,6-naphthalenedicarboxylic acid ester. Thus, the transesterification can be carried out by charging in a reaction vessel and gradually heating to 150 to 220 ° C. in the presence of a transesterification catalyst such as tetrabutoxytitanium.
In the esterification method, the total glycol component such as tetramethylene glycol is 1.2 to 1.6 times in molar ratio to the total acid component such as terephthalic acid and 2,6-naphthalenedicarboxylic acid. As described above, the esterification reaction can be carried out by gradually heating to 150 to 220 ° C. while being charged in a reaction vessel and pressurized with nitrogen.

After performing the transesterification reaction or esterification reaction, the pressure is reduced to 0.7 kPa abs or less, heated at about 230 to 260 ° C. for about 2 to 5 hours, and after performing the condensation polymerization reaction, It is discharged into a water tank and the chips cut with a strand cutter are quickly dried to remove the water adhering to the chips. In this way, the polyester resin (A) can be obtained.
Although it does not restrict | limit especially as a catalyst used when manufacturing a polyester resin (A), Zinc acetate, manganese acetate, magnesium acetate, etc. are mentioned as a transesterification catalyst, Antimony trioxide, germanium dioxide, Examples thereof include germanium tetrachloride and dibutyltin oxide. These catalysts are added in the range of 20 to 1000 ppm with respect to the total acid component.

Next, the metal (B) containing tin will be described.
The metal (B) containing tin is a component that imparts thermal conductivity to the polyester resin (A). The metal (B) containing tin is not particularly limited, and may be a simple substance of tin or an alloy of tin and a metal other than tin. The alloy of tin and a metal other than tin is not particularly limited. For example, Sn / Ag alloy, Sn / Bi alloy, Sn / Cu alloy, Sn / Zn alloy, Sn / Ag / Cu alloy, Sn / Ag / Bi / Cu alloy, Pb / Sn alloy, Pb / Sn / Ag alloy, Pb / Sn / Bi alloy and the like can be mentioned. Moreover, it is preferable to use as a mixture of tin and metals, such as Al, Cu, and Ni, from the point of thermal conductivity or dispersibility.

  Content of the metal (B) containing tin is 0.1 to 50 parts by mass when the total with the polyester resin (A) is 100 parts by mass. When the content of the metal (B) containing tin is 0.1 parts by mass or more, thermal conductivity tends to be good, and when it is 50 parts by mass or less, impact resistance tends to be good. The lower limit of the content of the metal (B) containing tin is more preferably 2 parts by mass or more, more preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more. Moreover, 35 mass parts or less are preferable, as for the upper limit of content of the metal (B) containing a tin, 30 mass parts or less are more preferable, and 25 mass parts or less are especially preferable.

The polyester resin composition of the present invention may contain other components in addition to the polyester resin (A) and the metal (B) containing tin. In particular, it is preferable to contain at least one filler selected from carbon fiber, graphite, metal fiber, and glass fiber. When containing at least one filler selected from carbon fiber, graphite, metal fiber, and glass fiber, the dispersibility of the tin-containing metal (B) in the polyester resin composition tends to be good. The thermal conductivity tends to be improved. Among these, graphite and carbon fiber are preferable, and pitch-based carbon fiber is particularly preferable among carbon fibers.
Although content in particular of these fillers is not restrict | limited, 0.1-100 mass parts is preferable with respect to a total of 100 mass parts of polyester resin (A) and the metal (B) containing tin. When the filler content is 0.1 parts by mass or more, thermal conductivity tends to be good, and when it is 100 parts by mass or less, impact resistance tends to be good. The lower limit of the content of these fillers is more preferably 1 part by mass or more, further preferably 10 parts by mass or more, and particularly preferably 20 parts by mass or more. Moreover, the upper limit of this content is more preferably 80 parts by mass or less, and particularly preferably 60 parts by mass or less.

In addition to the above filler, the polyester resin composition of the present invention contains an ultraviolet absorber, a light stabilizer, a lubricant, a polycarbonate, a polyamide, a polyphenylene oxide, a polyoxymethylene, a polymethyl methacrylate, and styrene as necessary. -Butadiene-acrylonitrile copolymer, styrene-acrylonitrile copolymer, at least one resin selected from polyester resins different from polyester resin (A); inorganic particles such as silica, talc, mica, kaolin, calcium carbonate; oxidation Additives such as pigments such as titanium and carbon black can be blended.
Although content in particular of these additives is not restrict | limited, 0.1-40 mass parts is preferable with respect to a total of 100 mass parts of polyester resin (A) and the metal (B) containing tin. When the additive content is 0.1 parts by mass or more, each improvement effect tends to be exhibited, and when it is 40 parts by mass or less, moldability, heat resistance, and impact resistance tend to be good. .

The polyester resin composition of the present invention is obtained by melt-kneading the aforementioned polyester resin (A) and a metal (B) containing tin. The method of melt kneading is not particularly limited, and examples thereof include a kneader, a roll, a single screw extruder, a twin screw extruder, and a multi screw extruder. Among these, an extruder is preferable because the kneading level is easily adjusted and pelletization after melt-kneading is easy.
The metal (B) containing tin is preferably partially or wholly melted at the time of melt kneading with the polyester resin (A) because the thermal conductivity of the polyester resin composition tends to be improved.

Next, the polyester molded body of the present invention will be described.
The polyester molded body of the present invention is formed by molding the above-described polyester resin composition.
The molding method is not particularly limited, and examples thereof include injection molding, press molding, extrusion molding, and blow molding. Among these, injection molding is preferable from the viewpoint of production stability and cost.

The thermal conductivity of a normal polyester molded body is about 0.3 W / m · K, but the thermal conductivity of the polyester molded body of the present invention is 1 W / m · K or more. The larger the thermal conductivity of the molded body, the more it can be used for an electrical component having a large calorific value.
Moreover, the impact resistance of the polyester molded body of the present invention is 50 J / m or more in terms of Izod impact strength.

Hereinafter, the present invention will be described in detail based on examples.
(1) Resin and resin composition evaluation method / resin composition analysis The resin composition of the polyester resin was analyzed by thermal decomposition chromatography and high-performance liquid chromatography of the alkaline decomposition product.
Intrinsic viscosity of resin and resin composition Polyester resin or a pulverized product of a polyester resin composition is dissolved in 50 ml of a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 1/1 (mass ratio). The soluble resin component was removed so as to be 250 mg and centrifuged at 1200 rpm for 40 minutes, and then the supernatant was measured at 25 ° C. with an Ubbelohde viscometer.

(2) Evaluation Method and Thermal Conductivity of Molded Body A measurement was performed by processing a 100 mm × 100 mm 3 mm molded product by a heat flow meter method.
-Impact resistance The test piece with 1/8 "notch was measured at 23 ° C according to ASTM D256.

(3) Production Example of Polyester Resin (A) / Polyester Resin (A) -1
100 mol parts of dimethyl terephthalate (hereinafter abbreviated as DMT), 140 mol parts of tetramethylene glycol (hereinafter abbreviated as BDO), and 600 ppm of tetrabutoxy titanium (corresponding to 1.5% by mass of the BDO solution) Was put in a reaction vessel equipped with a rectifying column and a stirring device, and the temperature was gradually raised to 220 ° C. while stirring. The transesterification reaction was carried out while discharging the distilled methanol out of the system, and then it was transferred to a polycondensation reaction vessel and subjected to condensation polymerization at 245 ° C. for 3 hours under a vacuum of 0.2 kPa abs or less, resulting in a predetermined stirring torque. By the way, what was discharged in the water tank in the form of a strand was turned into a chip with a strand cutter and dried at a predetermined temperature and time to obtain a polyester resin (A) -1. It was 0.96 dl / g when the intrinsic viscosity was measured about the obtained polyester resin (A) -1. Table 1 shows the analysis results of the resin composition.

・ Polyester resin (A) -2
A polyester resin (A) -2 was obtained in the same manner as the polyester resin (A) -1, except that the condensation polymerization time was 3 and a half hours. It was 1.05 dl / g when the intrinsic viscosity was measured about the obtained polyester resin (A) -2. Table 1 shows the analysis results of the resin composition.
・ Polyester resin (A) -3
A polyester resin (A) -3 was obtained in the same manner as the polyester resin (A) -1, except that the condensation polymerization time was 4 hours. It was 1.17 dl / g when the intrinsic viscosity was measured about the obtained polyester resin (A) -3. Table 1 shows the analysis results of the resin composition.
・ Polyester resin (A) -4
A polyester resin (A) -4 chip was obtained by subjecting a chip of the polyester resin (A) -1 to solid phase polymerization at 195 ° C. for 12 hours in a vacuum. It was 1.32 dl / g when the intrinsic viscosity was measured about the obtained polyester resin (A) -4. Table 1 shows the analysis results of the resin composition.

・ Polyester resin (A) -5
The polyester resin (A) -5 was prepared in the same manner as the polyester resin (A) -3, except that 95 mol parts of DMT and 5 mol parts of 2,6-naphthalenedicarboxylic acid dimethyl ester (hereinafter abbreviated as MNDA) were used. Obtained. It was 1.11 dl / g when intrinsic viscosity was measured about obtained polyester resin (A) -5. Table 1 shows the analysis results of the resin composition.
・ Polyester resin (A) -6
A polyester resin (A) -6 was obtained in the same manner as (A) -1, except that the condensation polymerization time was 2 and a half hours. It was 0.81 dl / g when the intrinsic viscosity was measured about the obtained polyester resin (A) -6. Table 1 shows the analysis results of the resin composition.

Example 1
Using a twin screw extruder (PCM-45 manufactured by Ikegai Seisakusho), after dry blending the components shown in Table 2 (the numerical values in the table represent parts by mass), the mixture was melt-kneaded at a resin temperature of 250 ° C. The molten resin was extruded from a circular die and the strand was solidified by water cooling, and then cut into pellets. The pressure was reduced from a vent port provided in the middle of the extruder to remove moisture and volatiles. The obtained pellets were dried with hot air at 120 ° C. for 4 hours to obtain a polyester resin composition.
This was measured with a J75SSII injection molding machine manufactured by Nippon Steel, with a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C., an ASTM standard physical property mold was molded in a molding cycle of 60 seconds, and an Izod test piece was molded and measured. Went. Moreover, after forming a flat plate with a 3 mm-thick film gate die of 100 mm × 100 mm and processing the shape, the thermal conductivity was measured. The evaluation results are shown in Table 2.

Examples 2-5
A polyester resin composition was obtained in the same manner as in Example 1 except that the resin composition of the polyester resin composition was changed to the components shown in Table 2, and an Izod test piece and a flat plate were obtained. The evaluation results are shown in Table 2.

Comparative Examples 1-3
A polyester resin composition was obtained in the same manner as in Example 1 except that the resin composition of the polyester resin composition was changed to the components shown in Table 2, and an Izod test piece and a flat plate were obtained. The evaluation results are shown in Table 2.
The comparative example 1 is an example which does not contain the metal (B) containing tin. Therefore, the thermal conductivity was as low as 0.3 W / m · K.
Comparative Example 2 is an example in which the intrinsic viscosity of the polyester resin (A) is as low as 0.81 dl / g. Therefore, in spite of having done otherwise similarly to Example 3, decomposition | disassembly of the polyester resin progressed and the impact strength was low.
Comparative Example 3 is an example in which the content of the metal (B) containing tin is as high as 58 parts by mass. Therefore, decomposition of the polyester resin progressed and the impact strength was low.

  Since the polyester molded product of the present invention has high thermal conductivity and good impact resistance, it is suitable for the electrical equipment field related to automobiles and home appliances.

Claims (3)

  It contains a dicarboxylic acid component (a) whose main component is an aromatic dicarboxylic acid unit (a1) and a glycol component (b) whose main component is a tetramethylene glycol unit (b1). Polyester resin having an intrinsic viscosity at 25 ° C. in the range of 0.9 to 1.5 dl / g when dissolved in a mixed solvent of 1,1,2,2-tetrachloroethane = 1/1 (mass ratio) A) Polyester resin composition obtained by melt-kneading 50 to 99.9 parts by mass and 0.1 to 50 parts by mass of tin-containing metal (B) (however, the sum of component (A) and component (B)) Is 100 parts by mass).   Furthermore, 0.1 to 100 parts by mass of at least one filler selected from carbon fiber, graphite, metal fiber, and glass fiber with respect to 100 parts by mass in total of the polyester resin (A) and the metal (B) containing tin. The polyester resin composition according to claim 1, wherein the polyester resin composition is melt kneaded.   A polyester molded article obtained by molding the polyester resin composition according to claim 1.