JP2013035987A - Copolyester resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin that is a polyester resin of which the flexibility at normal temperature is excellent and the brittleness is improved and that also has excellent wet heat durability and flame retardancy, and more specifically, a copolyester resin suitable for molding applications and potting applications of electric and electronic components etc.SOLUTION: The copolyester resin comprises: an acid component containing an aromatic dicarboxylic acid component and a dimer acid; and a glycol component containing 1,4-butanediol, polybutadiene glycols, and an ethylene oxide adduct of tetrabromobisphenol A, wherein the proportion of the dimer acid in the acid component in the copolyester resin is 10-50 mol%, the proportion of the 1,4-butanediol in the glycol component is 50 mol% or more, the proportion of the polybutadiene glycols in the glycol component is 0.5-20 mol%, and the proportion of the ethylene oxide adduct of tetrabromobisphenol A in the glycol component is 5-15 mol%.

Description

  The present invention is a resin obtained by copolymerizing a specific flame retardant component in a copolyester resin having a specific acid component and a glycol component, and is a copolymer excellent in flexibility, wet heat durability and flame resistance. The present invention relates to a polymerized polyester resin.

  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, 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.

  In addition, polyester resins and resin compositions suitable for molding are also used in applications such as electronic devices, automobiles, and building materials as described above. However, in recent years, flame resistance is required from the viewpoint of safety. Applications are increasing.

JP-A-2-3429 Japanese Patent Laid-Open No. 2003-176341

  The present invention solves the problems as described above, and is a polyester resin that has excellent flexibility at room temperature and improved brittleness, and also has excellent wet heat durability and flame retardancy. It is a technical problem to provide, more specifically, to provide a copolymerized polyester resin suitable for molding applications such as electrical / electronic parts and potting processing applications.

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 gist of the present invention is the following (1) and (2).
(1) Copolymer comprising an acid component containing an aromatic dicarboxylic acid component and a dimer acid, and a glycol component containing 1,4-butanediol, polybutadiene glycols, and an ethylene oxide adduct of tetrabromobisphenol A It is a polyester resin, and the proportion of the dimer acid in the acid component in the copolymerized polyester resin is 10 to 50 mol%, the proportion of 1,4-butanediol in the glycol component is 50 mol% or more, A copolymer polyester resin characterized in that the proportion of polybutadiene glycol is 0.5 to 20 mol%, and the proportion of tetrabromobisphenol A ethylene oxide adduct in the glycol component is 5 to 15 mol%.
(2) A method for producing a resin molded product comprising a step of obtaining a resin molded product by molding the resin according to (1) at a pressure of 5 MPa or less.

The copolyester resin in the present invention contains dimer acid in the acid component and a specific amount of polybutadiene glycol in the glycol component, and thus has excellent flexibility at room temperature, has an appropriate hardness, and is brittle. In addition, it has improved wet heat resistance. And since the copolymerized polyester resin of this invention is a thing which the ethylene oxide addition product of tetrabromobisphenol A was copolymerized, it also has the outstanding flame retardance.
For this reason, the copolyester resin of this invention can be used for various uses, such as a film, a fiber, a sheet | seat, and an adhesive agent. Further, the copolymer polyester resin of the present invention has excellent fluidity at the time of melting and can be injection-molded at a low pressure, so that a molded product having a thin part or a complicated shape can be provided by melt molding. is there. Furthermore, the copolyester resin 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 of the present invention is excellent in wet heat durability and flame retardancy, an electronic / electrical component obtained by insert molding of an electronic component as described above using the resin of the present invention And the like can be used for a long time in a harsh environment.

Hereinafter, the present invention will be described in detail. The copolymer polyester resin of the present invention includes an acid component containing an aromatic dicarboxylic acid and a dimer acid, and a glycol component containing 1,4-butanediol, polybutadiene glycols and an ethylene oxide adduct of tetrabromobisphenol A. It consists of
First, the acid component will be described. 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, and the content in the acid component is 50 to 90 mol%. preferable. When the content of the aromatic dicarboxylic acid is less than 50 mol%, the melting point of the copolyester resin is lowered, the heat resistance is inferior, and the mechanical strength tends to be lowered. On the other hand, when it exceeds 90 mol%, the ratio of dimer acid decreases, and the flexibility of the copolyester resin tends to be poor.

  The dimer acid in the present invention is obtained by thermally polymerizing an unsaturated fatty acid such as a refined vegetable fatty acid obtained from a drying oil or semi-drying oil, or by partially or completely hydrogenating it. Saturated fatty acid. These dimer acids are mainly composed of dimers of unsaturated fatty acids or hydrogenated products thereof, but also include trimers and tetramers. Commercially available products such as “Pripole”, “Plyplast” (manufactured by Croda), “Enpole”, “Sobamol” (manufactured by Cognis), “Unidim” (manufactured by Arizona Chemical) and the like can be used.

  And content of dimer acid in an acid component needs to be 10-50 mol%, and it is preferable that it is 20-40 mol% especially. By containing dimer acid as a copolymerization component, the resulting copolymerized polyester resin has excellent flexibility. Moreover, wet heat durability is also improved. When the content of the dimer acid in the acid component is less than 10 mol%, it becomes difficult to impart flexibility to the resulting copolyester resin, and the effect of improving wet heat durability is poor. On the other hand, when the content of dimer acid exceeds 50 mol%, the copolymer polyester resin obtained has a low melting point and becomes amorphous, so that it is inferior in heat resistance and mechanical strength tends to be low.

  The copolyester resin in the present invention contains the aromatic dicarboxylic acid and dimer acid as described above in the acid component, but other components are included as long as the effects of the present invention are not impaired. It may be. Examples of such other components include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and eicosanedioic acid.

The copolyester resin in the present invention contains 1,4-butanediol as a glycol component. The content of 1,4-butanediol in the glycol component is 50 mol% or more, preferably 60 to 98 mol%, more preferably 80 to 98 mol%. By containing 50 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. Therefore, when it is used for the purpose of molding, the content is preferably 80 to 98 mol%.
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 needs to be 0.5 to 20 mol% or more, preferably 2 to 18 mol%, more preferably 3 to 16 mol%.
When the polybutadiene glycol is contained in the glycol component, the copolymer polyester resin obtained is excellent in flexibility and wet heat durability. When the proportion of polybutadiene glycol is less than 0.5 mol%, it is difficult to make the resulting copolymer polyester resin excellent in flexibility and wet heat durability. 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, the flexibility of the resulting copolyester resin tends to be lowered.

  Examples of polybutadiene glycols include 1,2-polybutadiene glycol, 1,4-polybutadiene glycol, and the like, as well as hydrogenated polybutadiene glycol obtained by hydrogen reduction of these. 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.), and hydroxylated 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 is less likely to cause side reactions during the polycondensation reaction, it is possible to obtain a copolyester resin having better flexibility, wet heat durability, and the like.

  Furthermore, in order to impart flame retardancy to the copolymerized polyester resin of the present invention, an ethylene oxide adduct of tetrabromobisphenol A is copolymerized as a flame retardant component. The ethylene oxide adduct of tetrabromobisphenol A needs to be copolymerized as a glycol component in an amount of 5 to 15 mol%, preferably 7 to 12 mol%.

  If the copolymerization amount of tetrabromobisphenol A ethylene oxide adduct is less than 5 mol%, the flame-retardant performance of the copolyester resin is insufficient, making it difficult to use it in applications where flame-retardant performance is required. On the other hand, when it exceeds 15 mol%, the melting point of the copolyester resin is lowered and the heat resistance is poor.

  In the copolymerized polyester resin of the present invention, by using an ethylene oxide adduct of tetrabromobisphenol A as a copolymerization component, sufficient flame retardancy is obtained without impairing the excellent flexibility and wet heat durability of the copolymerized polyester resin. Can also be given.

  In the copolymerized polyester resin of the present invention, components other than 1,4-butanediol, polybutadiene glycols, and tetrabromobisphenol A ethylene oxide adduct are included in the glycol component as long as the effects of the present invention are not impaired. May also be contained. Examples of such other components include ethylene glycol, propylene glycol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol and propylene oxide adduct, polyethylene glycol, and polypropylene. Examples include glycol and polytetramethylene glycol.

  The copolyester resin of the present invention can be applied to a molding method similar to a known resin, 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 copolyester resin 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 is melted without using a solvent, and melted in a mold in which industrial parts (especially electronic parts) (hereinafter also referred to as “parts”) are placed. This is a method of injecting injected resin at a low pressure (preferably 0.1 to 3 MPa) and molding the resin (so-called insert molding) as the housing or case of the component. That is, the present invention includes a method for producing a resin molded product including a step of obtaining a resin molded product including an industrial part by injecting the resin of the present invention into a mold in which the industrial part is previously disposed. To do.

  The potting method in the present invention is a method in which a part is previously placed in a housing or on a substrate, and molten resin is injected or dropped at a low pressure (preferably 1 MPa or less) to integrate the housing or the substrate and the component. Say. That is, the present invention relates to a resin molded product including a step of obtaining a resin molded product including an industrial part by injecting or dropping the copolymerized polyester resin of the present invention into a housing or a substrate on which the industrial part is previously arranged. Includes manufacturing methods.

  Since the copolyester resin of the present invention is excellent in flexibility, adhesiveness, wet heat durability, etc., when it is used for hot melt molding or potting, it has not only good moldability but also a product ( The component 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 copolyester resin of the present invention is excellent in flame retardancy, and can be suitably used in applications that require flame retardancy.

  The copolyester resin 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, particularly 60 MPa or less. It is preferable that

  For Young's modulus, the polyester resin of the present invention was melted at a temperature 50 ° C. higher than the melting point of the resin using an injection molding machine “PS20E2ASE” manufactured by Nissei Plastic Industry Co., Ltd. Molding is performed to produce a molded sample having a thickness of 1 mm and a width of 3 mm. 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).

And the copolyester resin of this invention is excellent in a softness | flexibility by satisfying the above compositions, while being excellent in impact resistance and improved in brittleness. As an index indicating that the hardness is moderate and the brittleness is improved, the Shore D hardness at 20 ° C. is preferably 50 or less, and more preferably 45 or less.
The Shore D hardness is obtained by melting the copolymer polyester resin of the present invention at a temperature higher by 50 ° C. than the melting point, and using an injection molding machine “PS20E2ASE” manufactured by Nissei Plastic Industry Co., Ltd. Then, 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.

  If the Young's modulus at 20 ° C. exceeds 100 MPa, the copolymer polyester resin tends to be poor in flexibility. When the Shore D hardness at 20 ° C. exceeds 50, the copolymer polyester resin becomes a brittle resin with insufficient hardness, and is likely to be difficult to use for various applications.

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

  Furthermore, the copolyester resin 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 is greatly reduced by wet heat treatment, and a molded body using such a resin is inferior in shape stability. That is, the resin is inferior in wet heat durability.

The strain retention rate in the present invention is calculated as follows. The copolyester resin of the present invention is melted at a temperature higher by 50 ° C. than the melting point of the resin using an injection molding machine “PS20E2ASE” manufactured by Nissei Plastic Industry Co., Ltd., and injection molded into a mold at a pressure of 1 MPa. A molded sample of 1 mm and a width of 3 mm is produced. 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 copolyester resin of the present invention also has flame retardancy. As an indicator of flame retardancy, an oxygen index (hereinafter abbreviated as OI) is 27 or more in the combustion test described in JIS K7201. It is preferable that it is 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 copolyester resin of the present invention is also excellent in heat resistance, and the melting point is preferably 110 to 180 ° C, and particularly preferably 130 to 170 ° C. When the melting point is less than 110 ° 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 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 of this invention is demonstrated. After the esterification reaction of the above dicarboxylic acid, diol component and tetrabromobisphenol A ethylene ester at 150 to 250 ° C., polycondensation at 230 to 300 ° C. under reduced pressure in the presence of a polycondensation reaction catalyst, A copolyester resin can be obtained. Alternatively, a transesterification reaction is performed at 150 ° C. to 250 ° C. using a derivative such as dimethyl ester of dicarboxylic acid, a diol component, and an ethylene oxide adduct of tetrabromobisphenol A, and the pressure is reduced in the presence of a polycondensation reaction catalyst. A copolyester resin can be obtained by polycondensation at 230 ° C to 300 ° C.

When using the copolyester resin of the present invention, various additives may be added as long as the characteristics are not impaired. Examples of the additive include pigments, heat stabilizers, antioxidants, weathering agents, plasticizers, lubricants, mold release agents, antistatic agents, fillers, and crystal nucleating agents.
Examples of heat stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like. Inorganic 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, And hydrotalcite. Examples of the organic filler include naturally occurring polymers such as starch, cellulose fine particles, wood flour, okara, fir shell, bran, and modified products thereof. In addition, the method of adding these to the copolyester resin of this invention is not specifically limited.

  Moreover, when using the copolyester resin of this invention, you may use it with another polymer in the range which does not impair the characteristic. Examples of other polymers include polyethylene, polypropylene, polybutadiene, polystyrene, AS resin, ABS resin, poly (acrylic acid), poly (acrylic acid ester), poly (methacrylic acid), poly (methacrylic acid ester), and polyethylene terephthalate. , Resins such as polyethylene naphthalate, polycarbonate, and copolymers thereof.

  The copolymerized polyester resin 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 in the same manner as known polyester resins. For example, it can be used as various molded products such as films, fibers and sheets, and can also be used as an adhesive. In particular, when a film, fiber, or the like is obtained, 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. Moreover, when using it as an adhesive agent, for example, it can be used as an adhesive agent by forming it into a desired shape such as a sheet and then performing a heat treatment.

(1) Melting point It measured by the method similar to the above.
(2) Polymer composition The obtained copolymer polyester resin was dissolved in a mixed solvent having a volume ratio of 1/20 of deuterated hexafluoroisopropanol and deuterated chloroform, and the LA-400 NMR apparatus manufactured by JEOL Ltd. was used. 1H-NMR was measured and determined 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 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, a circuit board soldered with two lead wires made of vinyl chloride is used as a molding material, and insert molding is performed using an aluminum mold so that the copolyester resin and the circuit board are integrated. I got the 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 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 is injected into the housing at a pressure of 0.5 MPa. The electric parts were obtained by integrating them.
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
First, 56 parts by mass of terephthalic acid, 8 parts by mass of isophthalic acid, 67 parts by mass of hydrogenated dimer acid having 36 carbon atoms (Pripol 1009, manufactured by Croder Japan) as an acid component, and 1,4-butanediol as a diol component 54 parts by mass, 53 parts by mass of polybutadiene glycol (hydroxylated hydrogenated polybutadiene mainly having 1,2-repeat units; “GI-1000” manufactured by Nippon Soda Co., Ltd.), and ethylene oxide adduct 25 of tetrabromobisphenol A An esterification reaction was carried out by heating to 240 ° C. using parts by mass. 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 having the composition shown in Table 1.

Examples 2-7, Comparative Examples 1-2, 4-8
The type and amount of addition of ethylene oxide adducts of terephthalic acid, isophthalic acid, hydrogenated dimer acid, 1,4-butanediol, polybutadiene glycol, and tetrabromobisphenol A are changed to the compositions (contents) shown in Table 1. A copolymerized polyester resin was obtained in the same manner as in Example 1 except for the above.

Example 8
The same procedure as in Example 1 was conducted except that 1,4-butanediol and 1,6-hexanediol were used as glycol components, and the composition (content) shown in Table 1 was used. Obtained.

Comparative Example 3
A copolymer polyester resin 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 characteristic values and evaluation results of the copolyester resins obtained in Examples 1 to 8 and Comparative Examples 1 to 8.

  As is clear from Table 1, the copolymerized polyester resins obtained in Examples 1 to 8 had a composition satisfying the present invention, so that they were excellent in flexibility and had an 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. Among them, the copolyester resins obtained in Examples 1 to 7 are excellent in moldability when a molded product is obtained by hot melt molding or potting, and the obtained molded product is subjected to wet heat treatment at the time of molding. Both had sufficient insulating properties. 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 obtained in Comparative Example 1 had a low content of dimer 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. The copolymerized polyester resin obtained in Comparative Example 2 had a high content of dimer acid in the acid component and a low content of aromatic dicarboxylic acid component, so the melting point could not be measured (non-crystalline) It was inferior in heat resistance and moldability. Also, the tensile strength was low.

  The copolymerized polyester resin obtained in Comparative Example 3 did not contain 1,4-butanediol as a diol component, and was mainly composed of 1,6-hexanediol. In addition to being inferior, the moldability was also inferior. Since the copolymer polyester resin 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. Both had high Shore D hardness and Young's modulus and were inferior in 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 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 inferior, and the moldability was inferior. Also, the tensile strength was low.

The copolymerized polyester resin obtained in Comparative Example 7 had a low OI value and poor flame retardancy because of the low content of tetrabromobisphenol A ethylene oxide adduct. Since the copolymerized polyester resin obtained in Comparative Example 8 contained too much tetrabromobisphenol A ethylene oxide adduct, the melting point was low and the heat resistance was poor.

Claims (7)

A copolymer polyester resin comprising an acid component containing an aromatic dicarboxylic acid component and a dimer acid, and a glycol component containing 1,4-butanediol, polybutadiene glycols, and an ethylene oxide adduct of tetrabromobisphenol A In the copolymerized polyester resin, the proportion of dimer acid in the acid component is 10 to 50 mol%, the proportion of 1,4-butanediol in the glycol component is 50 mol% or more, and polybutadiene glycols in the glycol component A copolymerized polyester resin characterized in that the proportion of the ethylene oxide adduct of tetrabromobisphenol A in the glycol component is 5 to 20 mol%. The copolyester resin according to claim 1, wherein the Young's modulus at 20 ° C is 100 MPa or less. The copolymer polyester resin according to claim 1 or 2, wherein the Shore D hardness at 20 ° C is 50 or less. The copolyester resin according to any one of claims 1 to 3, which has an oxygen index of 27 or more in a combustion test. The manufacturing method of a resin molded product including the process of obtaining the resin molded product by shape | molding the resin in any one of Claims 1-4 at a pressure of 5 Mpa or less. The said process is a process of obtaining the resin molded product containing an industrial part by inject | pouring the resin in any one of Claims 1-4 in the metal mold | die with which the industrial part is arrange | positioned previously. Item 6. The manufacturing method according to Item 5. The step is a step of obtaining a resin molded product including an industrial part by injecting or dripping the resin according to any one of claims 1 to 4 into a housing or a substrate in which the industrial part is arranged in advance. The manufacturing method according to claim 5.