JP2013159701A - Copolymerized polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition which is a polyester resin composition excellent in flexibility at normal temperature, and reduced in brittleness, and has excellent wet heat durability and flame retardancy.SOLUTION: There is provided a copolymerized polyester resin composition comprising, based on 100 pts.mass of the copolymerized polyester composition: a copolymerized polyester resin (A) containing an aromatic dicarboxylic acid and a dodecanedioic acid as acid components, and 1,4-butanediol and polybutadiene glycols as glycol components, wherein the content of the dodecanedioic acid in the acid components is 20 to 50 mol%, the content of 1,4-butanediol in the glycol components is ≥80 mol%, and the content of the polybutadiene glycols in the glycol components is 0.5 to 20 mol%; and (B) an aromatic condensed phosphate ester compound of 2 to 30 pts.mass.

Description

  The present invention relates to a copolyester resin excellent in flexibility, heat resistance and flame retardancy, comprising an aromatic condensed phosphate ester compound in a copolyester resin containing a specific acid component and a glycol component. It relates to a composition.

  Polyesters, particularly copolyesters having polyethylene terephthalate (hereinafter abbreviated as PET) units or polybutylene terephthalate (hereinafter abbreviated as PBT) units as main components and copolymerized with aliphatic dicarboxylic acids or various diols are known. ing. Since this copolymer polyester has excellent heat resistance, weather resistance, solvent resistance, flexibility and the like, it is widely used as a film, fiber, sheet, various molded articles, and adhesives.

  However, the above copolyesters are brittle when used in applications requiring high flexibility, because they lack flexibility at low or normal temperatures. For this reason, there are limits to the applications that can be used.

  In order to improve such a defect, a method of copolymerizing a soft segment with a polyester resin has been proposed. 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 molding material used for electric / electronic parts, automobile parts and the like. 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. Furthermore, since the polyether compound, which is a soft segment, easily undergoes oxidative decomposition, thermal decomposition, etc. when exposed to high temperatures, there is a problem with the 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 as described in Patent Document 2 cannot provide sufficient flexibility, wet heat durability, adhesiveness, and the like. 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.

  Copolyesters based on PET or PBT units and copolymerized with aliphatic dicarboxylic acids or various diols are also used in applications such as electronic equipment, automobiles, and building materials, but are difficult from the viewpoint of safety. Flammability is required.

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

  The present invention solves the above problems, and is a polyester resin composition having excellent flexibility at room temperature, improved brittleness, and excellent wet heat durability and flame retardancy. Is to provide. More specifically, an object of the present invention is to provide a copolymerized polyester resin composition suitable for hot melt molding applications such as electric / electronic parts, potting processing applications, and the like.

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 comprising a copolymerized polyester resin (A) and an aromatic condensed phosphate ester compound (B), wherein the aromatic resin is aromatic relative to 100 parts by mass of the copolymerized polyester resin (A). The gist is a copolyester resin composition containing 2 to 40 parts by mass of the condensed phosphoric ester compound (B).

  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 the copolymerized polyester resin composition of the present invention contains an appropriate amount of the aromatic condensed phosphate ester compound, it also has excellent flame retardancy.

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. Further, since the resin composition of the present invention is excellent in fluidity at the time of melting and can be injection-molded at a low pressure, it is possible to provide a molded product having a thin part or a complicated shape by melt molding. . Furthermore, the resin composition of the present invention can be suitably used for hot melt molding applications in which insert molding of delicate electronic parts and the like is performed. Moreover, it can use suitably also for the potting use which puts components in a housing or on a board | substrate, inject | pours or drops resin on this, and integrates a housing or a board | substrate and components.
And since the copolyester resin composition of the present invention is excellent in wet heat durability and flame retardancy, the resin composition of the present invention was used and the electronic component was insert molded as described above. Electronic and electrical parts can be used for a long time in a harsh environment.

Hereinafter, the present invention will be described in detail.
First, the copolymerized polyester resin (A) will be described. 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 65 to 80 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%, and preferably 20 to 35 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 (A) in 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, terephthalate is used as the acid component. It is preferable to contain only acid and / or 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 copolyester resin (A) 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 (A). 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 copolyester resin (A) 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 copolymerization polyester resin composition of this invention contains the above-mentioned copolymerization polyester resin (A) and an aromatic condensed phosphate ester compound (B).

  Examples of the aromatic condensed phosphate ester compound (B) in the present invention include resorcinol polyphenyl phosphate, resorcinol poly (di-2,6-xylyl) phosphate, bisphenol A polycresyl phosphate, hydroquinone poly (2,6-xylyl). ) Condensed phosphate esters such as phosphate condensates. Examples of commercially available aromatic condensed phosphate ester compounds include PX-200, PX-201, PX-202, CR-733S, CR-741, and CR-747 manufactured by Daihachi Chemical Co., Ltd.

  In the copolymer polyester resin composition of the present invention, by using the aromatic condensed phosphate ester compound (B) as a flame retardant, the copolymer polyester resin (A) has excellent flexibility and wet heat durability. Sufficient flame retardancy can be imparted without loss.

  The aromatic condensed phosphate ester compound (B) is required to be contained in an amount of 2 to 40 parts by mass with respect to 100 parts by mass of the copolyester resin (A), and in particular, 5 to 35 parts by mass. Is preferred. When the content of the aromatic condensed phosphate ester compound (B) is less than 2 parts by mass, sufficient flame retardancy cannot be imparted to the copolyester resin (A), and flame retardancy is required. It becomes difficult to use for a use. On the other hand, when the content of the aromatic condensed phosphate ester compound (B) exceeds 40 parts by mass, the aromatic condensed phosphate ester compound (B) is uniformly melted and mixed in the copolymer polyester resin (A). It becomes difficult to obtain a resin composition.

  The copolyester resin composition of the present invention can be applied to a molding method similar to that of a known resin composition, but can be suitably used particularly for injection molding at a relatively low pressure. Specifically, it is optimal for molding at a pressure of 0.1 to 5 MPa, particularly 0.1 to 3 MPa. In this case, the temperature (melting temperature) varies depending on the type of resin component and the like, but is generally about 180 to 240 ° C. Therefore, the resin composition of the present invention is suitable for the hot melt molding method or the potting method.

  The hot melt molding method referred to in the present invention is a method in which a resin composition is melted without using a solvent, and an industrial part (particularly an electronic part) (hereinafter also referred to as “part”) is placed in advance in a mold. The molten resin composition is injected and injected at a low pressure (preferably 0.1 to 3 MPa), and the resin composition is molded (so-called insert molding) as the housing or case of the component.

  The potting method in the present invention refers to placing a part in a housing or on a substrate in advance and injecting or dropping the molten resin composition at a low pressure (preferably 1 MPa or less) to integrate the housing or the substrate and the part. The method of letting you say.

  Since the resin composition of the present invention is excellent in flexibility, adhesiveness, 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. In addition, the copolymer polyester resin of the present invention is excellent in flexibility, wet heat durability, and the like, so that the resin and the electronic component are hardly peeled off. In particular, even when used in a harsh environment for a long period of time, the resin and the electronic component do not peel off, and the resin portion is less likely to crack or crack.

  Furthermore, as described above, the resin composition of the present invention is excellent in flame retardancy, and can be suitably used in applications where flame retardancy is required.

The copolymerized polyester resin composition of the present invention is excellent in flexibility by satisfying the composition as described above, but as an index indicating flexibility, the Young's modulus at 20 ° C. is preferably 100 MPa or less. It is preferably 60 MPa or less.
Young's modulus is melted at a temperature 50 ° C. higher than the melting point of the copolymerized polyester resin (A) by using the injection molding machine “PS20E2ASE” manufactured by Nissei Plastic Industry Co., Ltd. A molding sample having a thickness of 1 mm and a width of 3 mm is produced by injection molding into a mold at a pressure of 1 MPa. This sample is measured at 20 ° C. and a tensile speed of 10 mm / min using a tensile tester “Tensilon” (UTM-4-100 manufactured by Orientec Corporation).

The copolymerized polyester resin composition of the present invention is excellent in flexibility by satisfying the above composition, and at the same time, is excellent in impact resistance and improved in brittleness. As an index indicating such moderate hardness and improved brittleness, the Shore D hardness at 20 ° C. is preferably 60 or less, and more preferably 55 or less.
The Shore D hardness is obtained by melting the resin composition of the present invention at a temperature 50 ° C. higher than the melting point, and using an injection molding machine “PS20E2ASE” manufactured by Nissei Plastic Industry Co., Ltd., and injection-molding the melt at a pressure of 1 MPa. A molded sample having a thickness of 3 mm and a width of 20 mm is prepared, and two of these samples are overlapped and measured at 20 ° C. using a Shore D hardness meter (WESTOP WR-105D). At this time, in the measurement with the Shore D hardness meter, the peak value is read within one second at a pressing load of 50 N, and the average value is calculated 10 times.

  When the Young's modulus at 20 ° C. exceeds 100 MPa, the copolymer polyester resin composition tends to be poor in flexibility. 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.

  The copolymer polyester resin composition of the present invention has excellent flexibility and improved brittleness by having the above-described composition. Therefore, the Young's modulus at 20 ° C. and the Shore at 20 ° C. Both the D hardness are preferably within the above range.

  Furthermore, the copolyester resin composition of the present invention is excellent in wet heat durability by having the above composition. As an index showing wet heat durability, the strain retention shown below is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. When the strain retention is less than 80%, the strength of the resin composition is greatly reduced by wet heat treatment, and a molded body using such a resin composition is inferior in shape stability. That is, the resin composition is inferior in wet heat durability.

The strain retention rate in the present invention is calculated as follows. The copolymer polyester resin composition of the present invention is melted at a temperature 50 ° C. higher than the melting point of the copolymer polyester resin (A) using an injection molding machine “PS20E2ASE” manufactured by Nissei Plastic Industry Co., Ltd. Injection molding is performed in the mold to produce a molded sample having a thickness of 1 mm and a width of 3 mm. Then, the 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

  The copolymerized polyester resin composition of the present invention has flame retardancy by containing the aromatic condensed phosphate ester compound (B). As an indicator of flame retardancy, JIS K7201 In the combustion test described in 1., the oxygen index (hereinafter abbreviated as OI) is preferably 27 or more, and more preferably 28 or more. If the OI value is less than 27, the flame retardancy is insufficient, and it is not suitable for electric / electronic component applications, which is not preferable.

The copolymer polyester resin composition of the present invention is also excellent in heat resistance, and the melting point is preferably 115 to 180 ° C, and particularly preferably 130 to 170 ° C. When the melting point is less than 115 ° 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, the thermal deterioration of the resin composition increases.
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.

Next, the manufacturing method of the copolyester resin composition of this invention is demonstrated. After the esterification reaction of the above dicarboxylic acid and glycol component at 150 to 250 ° C., polycondensation is performed at 230 to 300 ° C. under reduced pressure in the presence of a polycondensation reaction catalyst to obtain a copolyester resin (A). Can do. Alternatively, after a transesterification reaction at 150 ° C. to 250 ° C. using a derivative such as dimethyl ester of dicarboxylic acid as described above and a glycol component, polycondensation is performed at 230 ° C. to 300 ° C. while reducing the pressure in the presence of a polycondensation reaction catalyst. Thus, a copolyester resin (A) can be obtained.
An aromatic condensed phosphate ester compound (B) can be added to the obtained copolymer polyester resin (A) to obtain the copolymer polyester resin composition of the present invention. A batch blending method in which the polyester resin (A) and the aromatic condensed phosphate ester compound (B) are simultaneously added and melted and kneaded to form pellets, and after the copolymerized polyester resin (A) is melted and kneaded, Any of the split blending methods in which the aromatic condensed phosphate ester compound (B) is supplied from another supply port and melted, kneaded and pelletized may be employed.

In the copolymerized polyester resin composition of the present invention, pigments, heat stabilizers, antioxidants, weathering agents, plasticizers, lubricants, mold release agents, antistatic agents, fillers, as long as the properties are not significantly impaired. Further, a crystal nucleating agent or the like may be contained.
Examples of heat stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like. 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 composition of this invention is not specifically limited.

  In addition, when using the copolymerized polyester resin composition of the present invention, polyethylene, polypropylene, polybutadiene, polystyrene, AS resin, ABS resin, poly (acrylic acid), poly (acrylic acid), as long as the effect is not significantly impaired. Esters), poly (methacrylic acid), poly (methacrylic acid esters), polyethylene terephthalate, polyethylene naphthalate, polycarbonate, and copolymers thereof may be added.

  The copolymerized polyester resin composition of the present invention is suitable for the hot melt molding method and the potting method as described above, but can be used in various forms like the known polyester resin composition. For example, various molded products such as films, fibers, and sheets can be obtained. When obtaining a film, fiber or the like, it can be produced using a known method, apparatus, or the like. Moreover, when obtaining a sheet | seat or a molded object, it can shape | mold by well-known shaping | molding methods, such as injection molding, blow molding, extrusion molding, for example.

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 It measured by the method similar to the 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) Oxygen index (OI)
A combustion test described in JIS K7201 was performed to obtain OI. 27 or more were accepted.
(6) Tensile strength Using a molded sample obtained in the same manner as in (4), using a tensile tester “Tensilon” (UTM-4-100 type manufactured by Orientec Co., Ltd.), a tensile rate of 10 mm / min at 20 ° C. It is to measure with.

(7) 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).

(8) 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).

Example 1
As the acid component, 74 parts by mass of terephthalic acid, 11 parts by mass of isophthalic acid, and 40 parts by mass of dodecanedioic acid were used. As the glycol component, 79 parts by mass of 1,4-butanediol and polybutadiene glycol (mainly 1,2-repeating units were used). Hydroxylated hydrogenated polybutadiene (manufactured by Nippon Soda Co., Ltd., “GI-1000”) was used and heated to 240 ° C. to conduct a transesterification reaction. Next, 0.1 part by mass of tetra-n-butyl titanate was added as a catalyst, and finally the vacuum was raised to a high vacuum of 0.4 hPa while gradually raising the degree of vacuum at a temperature of 240 ° C. for 60 minutes. A time polycondensation reaction was performed to obtain a copolyester resin (A).
Next, with respect to 100 parts by mass of the obtained copolyester resin (A), 25 parts by mass of PX200 manufactured by Daihachi Chemical Industry Co., Ltd. was used as the aromatic condensed phosphate ester compound (B). Both components were added to a steelworks company, model TEX30C, screw diameter 30 mm), and each component was melted and kneaded at a cylinder setting temperature of 255 ° C. and a screw rotation speed of 200 rpm to obtain a copolymer polyester resin composition.

Examples 2-6, Comparative Examples 1, 2, 4-6
A copolymer polyester resin (A) was obtained in the same manner as in Example 1 except that the addition amounts of dodecanedioic acid, 1,4-butanediol, and polybutadiene glycol were changed.
And copolymerization is carried out similarly to Example 1 using 25 mass parts of aromatic condensed phosphate ester compounds (B) similar to Example 1 with respect to 100 mass parts of obtained copolymer polyester resin (A). A polyester resin composition was obtained.

Examples 7-8, Comparative Examples 7-8
A copolymer polyester resin composition was obtained in the same manner as in Example 1 except that the blending amount of the aromatic condensed phosphate ester compound (B) was changed to that shown in Table 1.

Comparative Example 3
A copolymer polyester resin (A) having the composition shown in Table 1 was obtained in the same manner as in Example 1 except that 1,6-hexanediol was used in place of 1,4-butanediol as the glycol component. . And the aromatic condensed phosphate ester compound (B) was added like Example 1, and the copolymerization polyester resin composition was obtained.

  Table 1 shows the compositions, characteristic values, and evaluation results of the copolymer polyester resin compositions obtained in Examples 1 to 8 and Comparative Examples 1 to 8.

  As is clear from Table 1, the copolymerized polyester resin compositions obtained in Examples 1 to 8 were of a composition satisfying the present invention, and therefore had excellent flexibility and appropriate hardness. The brittleness was improved. 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, the OI value was 28 or more, and it had sufficient flame retardancy. The copolymer polyester resins obtained in Examples 1 to 8 are particularly excellent in moldability when a molded product is obtained by a hot melt molding method or a potting method. 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 had a low content of dodecanedioic acid in the acid component, and therefore had high Shore D hardness and Young's modulus and poor flexibility. . Furthermore, since the strain retention was low and the wet heat durability was poor, the obtained molded product after the wet heat treatment did not have insulating properties. Since 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 the aromatic dicarboxylic acid component, the melting point could not be measured (non- Crystallinity) and poor heat resistance and moldability. Also, the tensile strength was low.

  The copolymerized polyester resin composition obtained in Comparative Example 3 did not contain 1,4-butanediol as a diol component, and was mainly composed of 1,6-hexanediol. It was inferior in moldability and inferior in 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 composition obtained in Comparative Example 5 contained polybutadiene glycol as a glycol component. Both had low Shore D hardness and Young's modulus and poor flexibility. Furthermore, since the strain retention was low and the wet heat durability was poor, the obtained molded product after the wet heat treatment did not have insulating properties. The copolymerized polyester resin composition obtained in Comparative Example 6 had an excessively high content of polybutadiene glycol as a glycol component, so that the melting point was low, the heat resistance was poor, and the moldability was poor. Also, the tensile strength was low.

The copolymerized polyester resin composition obtained in Comparative Example 7 had a low OI value and poor flame retardancy because of the low content of the aromatic condensed phosphate ester compound. In Comparative Example 8, since the content of the aromatic condensed phosphate ester compound was too large, the melt of the aromatic condensed phosphate ester compound was ejected from the tip of the extruder as a liquid at the time of melting and kneading. Kneading could not be performed and subsequent evaluation could not be performed.

Claims (4)

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 comprising (A) and an aromatic condensed phosphate ester compound (B), the aromatic condensed phosphate ester compound (100 parts by mass) based on 100 parts by mass of the copolyester resin (A). A copolymer polyester resin composition comprising 2 to 40 parts by mass of B). The copolymer polyester resin composition according to claim 1, wherein the Young's modulus at 20 ° C is 100 MPa or less. The copolymer polyester resin composition according to claim 1, wherein the Shore D hardness at 20 ° C. is 60 or less. The copolyester resin composition according to any one of claims 1 to 3, which has an oxygen index of 27 or more in a combustion test.