JP2013159700A - Copolymerized polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin composition which is excellent in flexibility at normal temperature, improved in brittleness, and further excellent in wet heat durability and crystal properties, and to provide a copolymerized polyester resin composition suitably used for molding or potting of electric and electronic components or the like.SOLUTION: A copolymerized polyester resin composition includes: a copolymerized polyester resin; and an inorganic crystal nucleating agent mixed thereto. The copolymerized polyester resin contains an aromatic dicarboxylic acid and a dodecanedioic acid as an acid component; and 1,4-butanediol and polybutadiene glycols as a glycol component, wherein the content of the dodecanedioic acid in the acid component is 20-50 mol%, the content of 1,4-butanediol in the glycol component is 80 mol% or more, and the content of polybutadiene glycols in the glycol component is 0.5-20 mol%. The content of the inorganic crystal nucleating agent in the resin composition is 0.01-5.0 mass%.

Description

  The present invention is a copolyester resin containing dodecanedioic acid in an acid component, 1,4-butanediol and polybutadiene glycol in a glycol component, and an inorganic crystal nucleating agent as a crystal nucleating agent The present invention relates to a copolymerized polyester resin composition excellent in flexibility, wet heat durability, and crystallinity.

  Polyester, particularly polyethylene terephthalate (hereinafter abbreviated as PET) or polybutylene terephthalate (hereinafter abbreviated as PBT) units as a main component, and a copolymerized polyester obtained by copolymerizing an aliphatic dicarboxylic acid or various diols are excellent. Since it has heat resistance, weather resistance, solvent resistance, flexibility, etc., it is widely used as a film, fiber, sheet, adhesive, and sealant.

  However, when the above-mentioned copolymerized polyester is used for an application that requires high flexibility, it is brittle due to lack of flexibility at low temperature or room temperature, and there is a limit to the use that can be used.

  In order to improve such a defect, a method of copolymerizing a soft segment with a polyester resin has been considered. A polyester-polyether block copolymer having a polyether compound as a soft segment has a low glass transition point of the resin, high fluidity, and the resin is flexible even when the molecular weight is reduced. For this reason, it is widely used as a material such as a molding material used in electric / electronic parts or automobile parts. Such a polyester-polyether block copolymer is disclosed in Patent Document 1, for example.

  However, this polyester-polyether block copolymer is susceptible to hydrolysis due to the ester bond of the hard segment, and the polyether compound that is a soft segment is likely to undergo oxidative degradation, thermal decomposition, etc. when exposed to high temperatures. As a result, there was a problem in wet heat durability of the copolymer itself.

  Patent Document 2 describes a polyester resin and a resin composition suitable for molding. The resin described in Patent Document 2 is suitable for molding applications for electric and electronic parts, and is described as being excellent in waterproofness, durability, fuel resistance, and the like.

  However, the composition described in Patent Document 2 cannot provide sufficient flexibility and wet heat durability. For this reason, when used for molding applications such as electrical / electronic parts, the product obtained from the resin may be used for a long period of time due to separation of the resin part from the internal electrical / electronic parts, cracks in the resin part, etc. Have the problem of not being able to.

  Furthermore, in addition to the above-described flexibility and wet heat durability, considering workability at the time of molding, it is also required to have a performance excellent in crystallinity. That is, by having high crystal performance, the cooling time for obtaining a molded product is shortened, and the product can be obtained in a short molding cycle. Such a polyester resin excellent in flexibility, wet heat durability and crystallinity has not yet been proposed.

JP-A-2-3429 JP 2003-176341 A

  The present invention solves the above-described problems, and is a polyester resin composition having excellent flexibility at room temperature and improved brittleness, excellent in wet heat durability, and crystallinity. It is a technical problem to provide a polyester resin composition that is also excellent for molding, and more specifically, to provide a copolymer polyester resin composition suitable for molding applications such as electrical and electronic parts and potting processing applications. To do.

The inventors of the present invention have arrived at the present invention as a result of studies to solve the above problems.
That is, the present invention contains an aromatic dicarboxylic acid and dodecanedioic acid as the acid component, 1,4-butanediol and polybutadiene glycols as the glycol component, and the dodecanedioic acid in the acid component. The content is 20 to 50 mol%, the content of 1,4-butanediol in the glycol component is 80 mol% or more, and the content of polybutadiene glycols in the glycol component is 0.5 to 20 mol%. A resin composition in which an inorganic crystal nucleating agent is blended in the copolymerized polyester resin, wherein the content of the inorganic crystal nucleating agent in the resin composition is 0.01 to 5.0% by mass. The gist of the present invention is a copolyester resin composition characterized by that.

The copolymerized polyester resin composition of the present invention is composed of a copolymerized polyester resin having a specific composition containing dodecanedioic acid and polybutadiene glycol as essential components. It has excellent hardness, improved brittleness, and excellent wet heat durability. Furthermore, since it contains a specific amount of an inorganic crystal nucleating agent, it has excellent crystal performance.
The copolymerized polyester resin composition of the present invention is excellent in moldability and can be formed into various molded products (containers, films, fibers, sheets) by injection molding, blow molding, extrusion molding, melt spinning, and the like. is there. The copolymer polyester resin composition of the present invention is excellent in fluidity at the time of melting and can be injection-molded at a low pressure. Therefore, it can be melt-molded even for thin-walled or complicated parts. It can be suitably used for applications. Furthermore, it can be suitably used for potting applications in which a part is placed in a housing or on a base, a resin is cast on the part, and the housing and the board are integrated with the part.
Since the copolyester resin composition of the present invention is excellent in wet heat durability, it can be suitably used for parts that can be used even in harsh environments such as electrical / electronic parts or automobile parts. Furthermore, since the crystal performance is also high, when obtaining a molded product, it is possible to obtain the product in a short molding cycle, and the operability is excellent.

Hereinafter, the present invention will be described in detail.
The copolyester resin constituting the copolyester resin composition of the present invention will be described. First, the acid component contains an aromatic dicarboxylic acid and dodecanedioic acid. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid, phthalic anhydride, naphthalenedicarboxylic acid, and the like. Derivatives may be used.

  The aromatic dicarboxylic acid contributes to increasing the melting point of the copolyester resin, imparting heat resistance and increasing mechanical strength. From this viewpoint, in the present invention, at least one of terephthalic acid and isophthalic acid is preferable as the aromatic dicarboxylic acid. The content (ratio) of the aromatic dicarboxylic acid in the acid component is preferably 50 to 80 mol%, and more preferably 60 to 75 mol%. When the ratio of the aromatic dicarboxylic acid is less than 50 mol%, the melting point of the copolyester resin becomes low, the heat resistance is inferior, and the mechanical strength tends to be low. On the other hand, when it exceeds 80 mol%, the proportion of dodecanedioic acid decreases, and the effect of improving the flexibility and wet heat durability of the copolyester resin tends to be poor.

  Dodecanedioic acid mainly increases the flexibility of the copolyester resin, improves brittleness, and contributes to improving wet heat durability. The content (ratio) of dodecanedioic acid in the acid component is required to be 20 to 50 mol%, preferably 25 to 40 mol%. By containing dodecanedioic acid as a copolymerization component, the resulting copolymerized polyester resin is excellent in flexibility, has an appropriate hardness, and is improved in brittleness. Furthermore, wet heat durability is also improved. When the proportion of dodecanedioic acid is less than 20 mol%, it becomes difficult to impart flexibility, appropriate hardness, wet heat durability, and the like to the resulting copolyester resin. On the other hand, when the proportion of dodecanedioic acid exceeds 50 mol%, the melting point of the resulting copolyester is lowered, the heat resistance is inferior, and the mechanical strength tends to be lowered.

  The copolyester resin in the present invention contains the above-mentioned aromatic dicarboxylic acid and dodecanedioic acid in the acid component, but other components are included as long as the effects of the present invention are not impaired. May be. Examples of such other components include succinic acid, adipic acid, azelaic acid, sebacic acid, and eicosane diacid.

  The copolymerized polyester resin of the present invention contains the aromatic dicarboxylic acid and dodecanedioic acid as described above in the acid component, but in order to sufficiently achieve the effects of the present invention, terephthalic acid and / or Or it is preferable to contain only isophthalic acid and dodecanedioic acid. When it contains other acid components other than these, it is preferable that it is as small as possible, and it is preferable that it is 5 mol% or less. Examples of other acid components include succinic acid, adipic acid, azelaic acid, sebacic acid, and eicosane diacid.

  Next, the copolymerized polyester resin of the present invention contains 1,4-butanediol as a glycol component. The content (ratio) of 1,4-butanediol in the glycol component is 80 mol% or more, preferably 85 to 98 mol%. By containing 80 mol% or more of 1,4-butanediol as the glycol component, the resulting copolymer polyester resin has a high melting point, excellent heat resistance, and excellent moldability. When 1,2-ethylene glycol is used instead of 1,4-butanediol, the resulting copolymer polyester resin has a low crystallization rate and poor moldability. When 1,6-hexanediol is used instead of 1,4-butanediol, the resulting copolymer polyester has a low melting point and is inferior in heat resistance.

Furthermore, polybutadiene glycols are contained in the glycol component of the copolyester resin in the present invention. The content of polybutadiene glycols in the glycol component is 0.5 to 20 mol%, preferably 2 to 15 mol%.
By containing polybutadiene glycols in the glycol component, the resulting copolymer polyester resin has excellent flexibility, improved brittleness, and excellent wet heat durability. When the ratio of the polybutadiene glycol is less than 0.5 mol%, it is difficult to impart flexibility and wet heat durability to the resulting copolyester resin. On the other hand, when the proportion of polybutadiene glycol exceeds 20 mol%, the melting point of the resulting copolyester resin becomes low, the heat resistance is poor, and the mechanical strength tends to be low.

  The polybutadiene glycols preferably have an average molecular weight of 350 to 6000, and more preferably 500 to 4500. When the average molecular weight of the polybutadiene glycol exceeds 6000, the compatibility is deteriorated and copolymerization tends to be difficult. On the other hand, if the molecular weight is less than 350, it tends to be difficult to improve the flexibility of the resulting copolymerized polyester resin.

  As polybutadiene glycols, 1,2-polybutadiene glycol, 1,4-polybutadiene glycol and the like, as well as hydrogenated polybutadiene glycol obtained by hydrogen reduction of these can be used. More specifically, for example, a diol obtained by polymerizing butadiene by anionic polymerization and introducing a hydroxyl group or a group having a hydroxyl group at both ends by terminal treatment, a diol obtained by hydrogen reduction of these double bonds (hydrogen Additive type polybutadiene glycol) and the like.

  As the polybutadiene glycols, known products or commercially available products can be used. Specifically, hydroxylated polybutadiene mainly having 1,4-repeating units (for example, “Poly bd R-45HT”, “Poly bd R-15HT” manufactured by Idemitsu Kosan Co., Ltd.), 1,2-repeating units Mainly hydroxylated polybutadiene (for example, “G-1000”, “G-2000”, “G-3000” manufactured by Nippon Soda Co., Ltd.), hydroxylated hydrogenated polybutadiene (for example, “GI-1000” manufactured by Nippon Soda Co., Ltd.) “GI-2000”, “GI-3000”) and the like.

  The polybutadiene glycols in the present invention are preferably hydrogenated polybutadiene glycols. Since hydrogenated polybutadiene glycol hardly causes side reactions during the polycondensation reaction, it becomes possible to obtain a copolymer polyester resin having more excellent flexibility and wet heat durability.

  The copolymerized polyester resin of the present invention contains 1,4-butanediol and polybutadiene glycols in the glycol component, but in order to sufficiently exhibit the effects of the present invention, 1,4-butanediol and It is preferable to contain only polybutadiene glycols. When it contains other glycol components other than these, it is preferable that it is as small as possible, and it is preferable that it is 5 mol% or less. Examples of other glycol components include ethylene glycol, propylene glycol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, ethylene oxide adduct and propylene oxide adduct of bisphenol A. , Polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like.

And the copolyester resin composition of this invention mix | blends an inorganic type crystal nucleating agent in the copolyester resin mentioned above. The content of the inorganic crystal nucleating agent in the copolymerized polyester resin composition needs to be 0.01 to 5.0% by mass, preferably 0.1 to 3.0% by mass. . By containing an appropriate amount of the inorganic crystal nucleating agent, the crystal performance can be improved without impairing the flexibility and wet heat durability performance of the copolyester resin.
If the content of the inorganic crystal nucleating agent is less than 0.01% by mass, the crystal performance of the copolyester resin cannot be improved, and it becomes difficult to improve the moldability of the resulting resin composition. . On the other hand, when the content of the inorganic crystal nucleating agent exceeds 5.0% by mass, the flexibility of the copolyester resin is impaired.

  As the inorganic crystal nucleating agent in the present invention, carbon black, silica, calcium carbonate, synthetic silicic acid and silicate, zinc white, halocyto clay, kaolin, basic magnesium carbonate, mica, talc, quartz powder, diatom Examples thereof include soil, dolomite cake, titanium oxide, zinc oxide, antimony oxide, barium sulfate, calcium sulfate, alumina, and calcium silicate. And it is preferable to use at least one of these inorganic compounds. Among them, as the inorganic crystal nucleating agent in the present invention, it is preferable to use at least one of talc, mica, kaolin, and silica, and it is preferable to use talc.

And as a parameter | index which shows that the copolyester resin composition of this invention is excellent in crystal performance, it is preferable that the DSC curve which shows the temperature-fall crystallization calculated | required from DSC satisfies following formula (1).
b / a ≧ 0.05 (mW / mg · ° C.) (1)

  The DSC curve showing the temperature-falling crystallization obtained from the DSC of the copolyester resin composition in the present invention is a temperature range of −20 ° C. to 20 ° C. in a nitrogen stream using a differential scanning calorimeter (Diamond DSC) manufactured by PerkinElmer. The measurement is performed at 250 ° C., a temperature rising (falling) rate of 20 ° C./min, and a sample amount of 2 mg.

  Said b / a is calculated | required from the DSC curve which shows the temperature-fall crystallization calculated | required from DSC. As shown in FIG. 1, in the DSC curve of the polyester resin composition, a is the temperature A1 (° C.) at the intersection of the tangent line and the baseline where the slope in the DSC curve showing the temperature-falling crystallization is maximum, and the slope is the minimum. Is the difference (A1-A2) between the temperature A2 (° C.) at the intersection of the tangent and the base line, and b is the heat amount B1 (mW) of the base line and the heat amount B2 (mW) of the peak top at the peak top temperature. (B1-B2) divided by the amount of sample (mg).

  b / a is an index representing the crystallinity when the temperature is lowered, and the higher the b / a value, the faster the crystallization rate, and vice versa, the closer to 0, the slower the crystallization rate. That is, the higher the value of b / a, the better the crystallinity at lowering the temperature, so that a molded product can be obtained in a short molding cycle and the productivity is excellent. On the other hand, when b / a is less than 0.05 (mW / mg · ° C.), the crystallization rate is slow, so the molding cycle for obtaining a molded product becomes long and the productivity is poor. Further, blocking tends to occur when the polyester resin composition is chipped, stored or transported, or in the drying process.

  The copolyester resin in the present invention is composed of a specific acid component and a glycol component essential for the above-mentioned dodecanedioic acid and polybutadiene glycol, so that it is excellent in flexibility and has an appropriate hardness. And having improved brittleness. Furthermore, it becomes excellent in wet heat durability. And it is preferable that the copolymerization polyester resin composition of this invention satisfies the following parameters | indexes as a parameter | index which shows such performance.

  First, the copolyester resin composition of the present invention preferably has a Young's modulus at 20 ° C. of 100 MPa or less, particularly 10 to 80 MPa, as an index indicating flexibility. The Young's modulus was injection-molded using an injection molding machine “PS20E2ASE” manufactured by Nissei Plastic Industry Co., Ltd. to produce a molded sample having a thickness of 1 mm and a width of 3 mm. “Tensilon” (UTM-4-100 type manufactured by Orientec Co., Ltd.) is used and measured at 20 ° C. and a tensile speed of 10 mm / min.

  And as a parameter | index which shows that the copolymerization polyester resin composition of this invention has moderate hardness and the brittleness is improved, the Shore D hardness in 20 degreeC is 60 or less. Among these, 20 to 55 is particularly preferable. For the Shore D hardness, the copolymer polyester resin composition of the present invention was injection molded using an injection molding machine “PS20E2ASE” manufactured by Nissei Plastic Industry Co., Ltd., and a molded sample having a thickness of 3 mm and a width of 20 mm was prepared. Measurement is performed using a Shore D hardness tester (WESTOP WR-105D) at 20 ° C. by stacking the sheets.

  When the Young's modulus at 20 ° C. exceeds 100 MPa, the copolymer polyester resin composition tends to be poor in flexibility. On the other hand, if the Young's modulus is less than 10 MPa, the molding processability tends to be lowered. On the other hand, when the Shore D hardness at 20 ° C. exceeds 60, the copolymer polyester resin composition becomes a brittle resin with insufficient hardness, and is likely to be difficult to use for various applications. On the other hand, when the Shore D hardness is less than 20, molding processability tends to be lowered. The copolymerized polyester resin composition of the present invention preferably satisfies both the above Young's modulus and Shore D hardness.

Furthermore, as an index indicating that the copolymer polyester resin composition of the present invention is excellent in wet heat durability, the strain retention shown below is preferably 80% or more, more preferably 85% or more, Is preferably 90% or more. When the strain retention is less than 80%, the strength of the resin is greatly reduced by wet heat treatment, and a molded body using such a resin composition is inferior in shape stability. That is, it becomes a molded article that is difficult to use for a long time in a humid heat environment.
The strain retention rate in the present invention is calculated as follows. Using the injection molding machine “PS20E2ASE” manufactured by Nissei Plastic Industry Co., Ltd., the copolymer polyester resin composition of the present invention was injection-molded into a mold at a pressure of 1 MPa and melted at a temperature 50 ° C. higher than the melting point. A molded sample having a width of 1 mm and a width of 3 mm is prepared, and tensile fracture strain is measured according to the method described in ISO standard 527-2 (tensile fracture strain before treatment). Using a thermo-hygrostat (IG400 type manufactured by Yamato Kagaku Co., Ltd.), the obtained molded sample is stored for 200 hours in an environment of a temperature of 60 ° C. and a humidity of 95% RH, and is subjected to a wet heat treatment. The tensile fracture strain of the sample after the wet heat treatment is measured in the same manner as described above, and is calculated by the following formula.
Strain retention (%) = [(Tensile fracture strain after treatment) / (Tensile fracture strain before treatment)] × 100

Furthermore, the copolyester resin composition of the present invention is excellent in heat resistance, and the melting point is preferably 120 to 180 ° C, and particularly preferably 130 to 170 ° C. When the melting point is less than 120 ° C., the heat resistance is poor, and the use is limited. On the other hand, if it exceeds 180 ° C., it is necessary to increase the processing temperature at the time of molding, which is disadvantageous in terms of cost, and at the same time, thermal degradation of the resin also increases. Since the copolymerized polyester resin composition of the present invention has such a melting point, it is excellent in moldability.
The melting point is measured by using a Perkin Elmer Diamond DSC, raising and lowering the temperature at 10 ° C./min, and the melting peak temperature.

  The copolymer polyester resin composition of the present invention preferably has a melt viscosity at 200 ° C. of 1 Pa · s to 300 Pa · s, and more preferably 10 to 150 Pa · s. When the melt viscosity is within this range, molding at a low pressure is possible, which is suitable for hot melt molding applications and potting applications. Specifically, molding at a pressure of 0.1 to 5 MPa, particularly 0.1 to 3 MPa is possible.

When the melt viscosity exceeds 300 Pa · s, the fluidity becomes low and molding at low pressure becomes difficult. Further, when the melting temperature is increased in order to reduce the melt viscosity, the load on the apparatus is increased, and the thermal deterioration of the copolyester resin composition becomes remarkable. On the other hand, when the melt viscosity is less than 1 Pa · s, the strength of the copolyester resin composition tends to be low.
The melt viscosity is measured by a flow tester (manufactured by Shimadzu Corporation, model CFT-500) using a nozzle having a nozzle diameter of 1.0 mm and a nozzle length of 10 mm and a shear rate of 1000 sec ^−1. is there.

  The hot melt molding method referred to in the present invention is a method in which a resin is melted without using a solvent, and the molten resin is put into a mold in which industrial parts (especially electronic parts) are arranged in advance. 0.1-3 MPa) and injection molding and resin molding (so-called insert molding) as the housing or case of the part.

  The potting method in the present invention refers to placing an industrial part in a housing or on a substrate in advance, and pouring or dropping molten resin at a low pressure (preferably 1 MPa or less) to integrate the housing or the substrate and the component. The method of making it.

  Since the copolymerized polyester resin composition of the present invention is excellent in flexibility, wet heat durability, etc., when it is used for hot melt molding or potting, not only has good moldability but also a product (parts) to be obtained. ) Is excellent in adhesion between the electronic component to be inserted and the resin, and the resin and the electronic component are hardly separated. For this reason, even if it is used for a long time in a harsh environment, the resin and the electronic component are not separated from each other, and the resin portion is not easily cracked or cracked.

Next, the manufacturing method of the copolyester resin composition of this invention is demonstrated.
After the above acid component and glycol component are esterified at 150 to 250 ° C., an inorganic crystal nucleating agent is added, and the pressure is reduced in the presence of a polycondensation reaction catalyst (preferably from atmospheric pressure to about 10 to 30 Pa). The copolymerized polyester resin composition of the present invention can be obtained by polycondensation at 230 to 300 ° C. (under reduced pressure). Also, for example, a derivative such as dimethyl ester of an aromatic dicarboxylic acid and a glycol component are transesterified at 150 ° C. to 250 ° C., an inorganic crystal nucleating agent is added, and the pressure is reduced in the presence of a polycondensation reaction catalyst. The copolymerized polyester resin composition of the present invention can be obtained by polycondensation at 230 ° C. to 300 ° C. while reducing the pressure (preferably from atmospheric pressure to about 10 to 30 Pa).

In the copolymerized polyester resin composition of the present invention, pigments, heat stabilizers, antioxidants, weathering agents, flame retardants, plasticizers, lubricants, mold release agents, antistatic agents, as long as the properties are not significantly impaired. A filler or the like may be added.
Examples of heat stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like. As the flame retardant, a halogen-based flame retardant, a phosphorus-based flame retardant, and an inorganic flame retardant can be used. However, in consideration of the environment, it is desirable to use a non-halogen flame retardant. Non-halogen flame retardants include phosphorus flame retardants, hydrated metal compounds (aluminum hydroxide, magnesium hydroxide, etc.), nitrogen-containing compounds (melamine-based, guanidine-based), inorganic compounds (borates, Mo compounds, etc.) Is mentioned.
Fillers include layered silicate, calcium carbonate, zinc carbonate, wollastonite, silica, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, antimony trioxide, zeolite, hydro Examples include talcite.
In addition, the method of adding these to the copolyester resin of this invention is not specifically limited.

  Further, when the copolymerized polyester resin composition of the present invention is used, polyethylene, polypropylene, polybutadiene, polystyrene, AS resin, ABS resin, poly (acrylic acid), poly (acrylic acid ester), as long as the effect is not impaired. ), Poly (methacrylic acid), poly (methacrylic acid ester), polyethylene terephthalate, polyethylene naphthalate, polycarbonate, and copolymers thereof may be used.

Next, the present invention will be specifically described using examples. The measurement and evaluation methods for various characteristic values in the examples are as follows.
(1) Melting point, melt viscosity, DSC curve showing temperature drop crystallization determined from DSC Measurement was performed in the same manner as above.
(2) Polymer composition The obtained copolymer polyester resin composition was dissolved in a mixed solvent having a volume ratio of 1/20 of deuterated hexafluoroisopropanol and deuterated chloroform, and LA-400 type NMR apparatus manufactured by JEOL Ltd. 1H-NMR was measured at 1 and obtained from the integrated intensity of the proton peak of each copolymer component in the obtained chart.
(3) Shore D hardness, Young's modulus It measured by the method similar to the above.
(4) Tensile fracture strain, strain retention (wet heat durability)
It measured by the method similar to the above.
(5) Tensile strength Using a molding sample obtained in the same manner as in (4), using a tensile tester “Tensilon” (UTM-4-100 manufactured by Orientec Co., Ltd.), a tensile rate of 10 mm / min at 20 ° C. It is to measure with.

(6) Formability 1 (hot melt molding)
The obtained copolyester resin composition was melted at a temperature higher by 50 ° C. than the melting point, and injection molding was performed at a pressure of 1 MPa using “PS20E2ASE” manufactured by Nissei Plastic Industries. At this time, the copolymer polyester resin composition and the circuit board are integrated by insert molding using an aluminum mold using a circuit board soldered with two lead wires made of vinyl chloride as a molding material. Got the electrical parts. Formability at the time of obtaining a part was evaluated in the following three stages according to the time (release time) in which the mold can be released.
○: The mold release time was within 10 seconds.
Δ: The mold release time exceeded 10 seconds and was within 20 seconds.
X: The mold release time exceeded 20 seconds.
For parts with the above-mentioned moldability, when the parts are obtained (before treatment), the parts are left in the environment of 80 ° C. and 95% for 500 hours (after wet heat treatment) The insulation characteristics of were evaluated as follows.
○… Insulation property is maintained.
X: Insulation property is broken.
In the circuit board, the soldered portions (two locations) of the two lead wires are not connected. Therefore, normally, electricity does not flow between the lead wires (insulation is maintained). If water enters between the resin and the circuit board after the wet heat treatment, the water becomes a conductor and current flows between the lead wires (insulation is broken).
(7) Formability 2 (potting)
The obtained copolyester resin composition was melted at a temperature 50 ° C. higher than the melting point. Then, the same circuit board as that used in the moldability 1 is placed in the housing (container type), and the molten copolyester resin composition is injected into the housing at a pressure of 0.5 MPa. The substrate was integrated to obtain an electrical component. The moldability at the time of obtaining parts was visually evaluated in the following three stages.
○: The resin flows into the entire part, and there are no irregularities on the surface.
Δ: Resin flows into the entire part, but irregularities are seen in the shape.
X: The resin flow is insufficient and a part of the circuit board is exposed.
For parts with the above-mentioned moldability, when the parts are obtained (before treatment), the parts are left in the environment of 80 ° C. and 95% for 500 hours (after wet heat treatment) The insulation characteristics of were evaluated as follows.
○… Insulation property is maintained.
X: Insulation property is broken.
In the circuit board, the soldered portions (two locations) of the two lead wires are not connected. Therefore, normally, electricity does not flow between the lead wires (insulation is maintained). If water enters between the resin and the circuit board after the wet heat treatment, the water becomes a conductor and current flows between the lead wires (insulation is broken).
(8) Formability 3 (molding cycle)
An ISO dumbbell-shaped test piece was molded from the obtained copolymer polyester resin composition using an injection molding machine (trade name “IS-80G” manufactured by Toshiba Machine Co., Ltd.). The resin composition was melted at a molding temperature 50 ° C. higher than the melting point, and filled in a mold having a mold temperature of 20 ° C. When the resin composition is injected into the mold, the total of the injection time and the pressure applied after the injection is 10 seconds, and then the molded body can be fixed to the mold or taken out without resistance. The total time (molding cycle) (seconds) with the time required to release the mold without any deformation due to the protruding pin was measured and evaluated according to the following criteria.
A: Required time is 5 seconds or less.
○: The required time is longer than 5 seconds and not longer than 10 seconds.
X: The required time exceeds 10 seconds.

Example 1
As an acid component, 108 parts by mass of terephthalic acid and 81 parts by mass of dodecanedioic acid are used. As a diol component, 117 parts by mass of 1,4-butanediol and polybutadiene glycol (hydroxyl hydrogenation mainly having 1,2-repeating units) Using 72 parts by mass of polybutadiene (manufactured by Nippon Soda Co., Ltd., “GI-1000”), 0.1 part by mass of tetra-n-butyl titanate was added as a catalyst, and the mixture was heated to 240 ° C. for transesterification. Next, 2 parts by mass of talc having an average particle diameter of 1.0 μm was added as an inorganic crystal nucleating agent, and finally the vacuum was raised to a high vacuum of 0.4 hPa while gradually increasing the degree of vacuum at a temperature of 240 ° C. for 60 minutes. Then, a polycondensation reaction was carried out for 4 hours, and after completion of the reaction, the polycondensation reaction was carried out to obtain a copolyester resin composition having the composition shown in Table 1.

Examples 2-9, Comparative Examples 1-2, 4-6, 8-10
Example 1 except that the addition amount of terephthalic acid, isophthalic acid, dodecanedioic acid, 1,4-butanediol, polybutadiene glycol, and talc was changed to the composition (content) shown in Table 1. To obtain a copolymerized polyester resin composition. In Example 8, talc having an average particle diameter of 2.0 μm was used. In Example 9, “GI-2000” (hydroxylated hydrogenated polybutadiene mainly having 1,2-repeat units) manufactured by Nippon Soda Co., Ltd. was used as polybutadiene glycol.

Comparative Example 3
Copolymerized polyester resin composition was carried out in the same manner as in Example 1 except that 1,4-butanediol and 1,6-hexanediol were used as the glycol component and the composition (content) shown in Table 1 was used. I got a thing.

Comparative Example 7
A copolymer polyester resin composition was obtained in the same manner as in Example 1 except that only 1,6-hexanediol was used as the glycol component and the composition (content) shown in Table 1 was used.

  Table 1 shows the compositions, characteristic values, and evaluation results of the copolymer polyester resin compositions obtained in Examples 1 to 9 and Comparative Examples 1 to 10.

  As is apparent from Table 1, the copolymer polyester resin compositions obtained in Examples 1 to 9 had a composition satisfying the present invention, and therefore, the Young's modulus at 20 ° C. was 78 MPa or less and 20 ° C. The shore D hardness was 46 or less, excellent flexibility, moderate hardness, and improved brittleness. And the value of tensile fracture strain and the retention rate were both high, and it was excellent in strength and wet heat durability. Furthermore, since the crystal performance is high and the DSC curve indicating the temperature drop crystallization obtained from DSC satisfies the formula (1), a molded product can be obtained in a short molding cycle, and the moldability can be evaluated. It was excellent. Furthermore, the copolymerized polyester resin compositions obtained in Examples 1 to 9 are also excellent in moldability when a molded product is obtained by hot melt molding or potting. It had sufficient insulation properties both after heat treatment. That is, the molded product obtained by both methods has good adhesion between the resin and the part, and can be used for a long time even in a harsh environment.

On the other hand, the copolymerized polyester resin composition obtained in Comparative Example 1 has a small content of dodecanedioic acid in the acid component, and therefore has a high Shore D hardness, Young's modulus and poor flexibility. The strain retention was low and the wet heat durability was poor. The copolymerized polyester resin composition obtained in Comparative Example 2 had a high content of dodecanedioic acid in the acid component and a low content of aromatic dicarboxylic acid, and therefore had a low melting point and poor heat resistance. In addition, the crystal performance was inferior (measurement by DSC curve was not possible) and the moldability was also inferior. Moreover, the tensile strength was also inferior. Since the copolymer polyester resin composition obtained in Comparative Example 3 had a ratio of 1,4-butanediol as a diol component of less than 80 mol%, the copolymer polyester resin composition obtained in Comparative Example 7 was Since it did not contain 1,4-butanediol as a diol component and was mainly composed of 1,6-hexanediol, both resins had low melting points and poor heat resistance. Furthermore, it was inferior to evaluation of moldability. Since the copolymer polyester resin composition obtained in Comparative Example 4 did not contain polybutadiene glycol as a glycol component, the copolymer polyester resin obtained in Comparative Example 5 had a low content of polybutadiene glycol as a glycol component. Therefore, the Young's modulus and Shore D hardness were high and the flexibility was poor, and the strain retention was low and the wet heat durability was poor. Since the copolymer polyester resin obtained in Comparative Example 6 contained too much polybutadiene glycol as a glycol component, the melting point was low, the heat resistance was inferior, the crystal performance was inferior, and the DSC curve satisfied the formula (1). However, the molding cycle was long and the evaluation of moldability was inferior. Moreover, the tensile strength was also inferior. Since the copolyester resin obtained in Comparative Example 8 did not contain an inorganic crystal nucleating agent, the copolyester resin obtained in Comparative Example 9 had too little content of the inorganic crystal nucleating agent. In either case, the crystal performance was inferior, the DSC curve did not satisfy the formula (1), the molding cycle was long, and the moldability was inferior. The copolymerized polyester resin composition obtained in Comparative Example 10 had a high Young's modulus and poor flexibility because the content of the inorganic crystal nucleating agent was too large.

Claims (5)

The acid component contains an aromatic dicarboxylic acid and dodecanedioic acid, the glycol component contains 1,4-butanediol and polybutadiene glycols, and the content of dodecanedioic acid in the acid component is 20-50. Copolyester resin in which the content of 1,4-butanediol in the glycol component is 80 mol% or more and the content of polybutadiene glycols in the glycol component is 0.5 to 20 mol% A resin composition in which an inorganic crystal nucleating agent is blended, wherein the content of the inorganic crystal nucleating agent in the resin composition is 0.01 to 5.0% by mass. Copolyester resin composition. The copolymer polyester resin composition according to claim 1, wherein the inorganic crystal nucleating agent is at least one of talc, mica, kaolin, and silica. The copolyester resin composition according to claim 1 or 2, wherein a DSC curve showing temperature-fall crystallization determined by DSC satisfies the following formula (1).
b / a ≧ 0.05 (mW / mg · ° C.) (1)
Note that a is the temperature A1 (° C.) of the intersection between the tangent line and the baseline where the slope is maximum in the DSC curve indicating the temperature-falling crystallization, and the temperature A2 (° C.) B) is the difference (B1-B2) between the baseline heat quantity B1 (mW) and the peak top heat quantity B2 (mW) at the peak top temperature (mg) The value divided by. The copolymer polyester resin composition according to any one of claims 1 to 3, wherein Young's modulus at 20 ° C is 100 MPa or less. The copolymer polyester resin composition according to any one of claims 1 to 4, which has a Shore D hardness of 50 or less at 20 ° C.