JP3346904B2 - Sealing material for electric and electronic parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing material for electric and electronic parts which has excellent fluidity during injection molding and can prevent damage to a sealed electric and electronic element.

[0002]

2. Description of the Related Art Conventionally, sealing with a thermoplastic resin has been performed for the purpose of protecting electric and electronic parts. For example, Japanese Patent Application Laid-Open No. 60-40163 discloses a polymer liquid crystal (LCP).
The sealing of an electronic component using a resin is exemplified.
According to the gazette, when sealing with a resin by injection molding using LCP, when the melt viscosity of LCP is high, high pressure is required in injection molding, and as a result, precision electronic components subjected to encapsulation molding are expensive. May be damaged by pressure. Also, if the melt viscosity is high, the molding material is prevented from flowing sufficiently into the mold to form voids (voids). As a result, moisture or the like reaches the electronic components through the voids, resulting in defective insulation. Is generated.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to develop a sealing material comprising a wholly aromatic polyester which can be molded even at a low injection pressure.

[0004]

That is, the first aspect of the present invention is as follows.
Is an optical melting difference in which the difference (Tη ₂ −Tη ₁ ) between the melting completion temperature (Tη ₂ , ° C.) and the solidification onset temperature (Tη ₁ , ° C.) determined by the capillary rheometer is in the range of 10 to 80 ° C. The present invention relates to a sealing material for electric and electronic parts, which is made of a wholly aromatic polyester having anisotropy. A second aspect of the present invention relates to a sealing material for electric / electronic parts, wherein the melting point of the first wholly aromatic polyester of the present invention is in the range of 300 to 450 ° C. Further, the third aspect of the present invention relates to the first wholly aromatic polyester of the present invention and 10 to 9 parts by weight of the whole composition.
The present invention relates to a sealing material for electric and electronic parts, comprising 5% by weight of an inorganic filler.

Hereinafter, the present invention will be further described. The thermotropic liquid crystal polyester of the present invention is a polymer that exhibits optical anisotropy when melted and has thermoplasticity.
As described above, a polymer that exhibits optical anisotropy at the time of melting exhibits a property that the polymer molecular chains take a regular parallel arrangement in a molten state. The properties of the optically anisotropic molten phase can be confirmed by a usual polarization inspection method using a crossed polarizer.
A thermotropic liquid crystal polymer generally has an elongated and flat molecular structure, and has high rigidity along a long chain of the molecule.
In the thermotropic liquid crystal polyester used in the present invention, a part of one polymer chain is composed of a polymer segment that forms an anisotropic molten phase, and the remaining part is a polymer segment that does not form an anisotropic molten phase. Also included are polymers composed of Further, a composite of a plurality of thermotropic liquid crystal polymers is also included.

Representative examples of the monomers constituting the thermotropic liquid crystal polyester include (A) at least one kind of aromatic dicarboxylic acid, (B) at least one kind of aromatic hydroxycarboxylic acid type compound, and (C) aromatic diol type compound. (D) (D ₁ ) aromatic dithiol, (D ₂ ) aromatic thiophenol, (D ₃ ) at least one aromatic thiol carboxylic acid compound, (E) aromatic hydroxylamine, aromatic And aromatic compounds such as at least one of aromatic diamine compounds. These may be composed alone, but in many cases (A) and (C);
(A) and (D); (A), (B) and (C); (A),
(B) and (E); or (A), (B), and (C) and (E) in combination.

The above (A) aromatic dicarboxylic acid compounds include terephthalic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-terphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 1,4- Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenoxyethane-
4,4'-dicarboxylic acid, diphenoxybutane-4,4'-
Dicarboxylic acid, diphenylethane-4,4'-dicarboxylic acid, isophthalic acid, diphenylether-3,3'-dicarboxylic acid, diphenoxyethane-3,3'-dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid, 1,6
Aromatic dicarboxylic acids such as naphthalenedicarboxylic acid, or chloroterephthalic acid, dichloroterephthalic acid, bromoterephthalic acid, methylterephthalic acid, dimethylterephthalic acid, ethylterephthalic acid, methoxyterephthalic acid,
Alkyl, alkoxy or halogen substituents of the above aromatic dicarboxylic acids represented by ethoxy terephthalic acid and the like.

(B) The aromatic hydroxycarboxylic acid compound includes aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and 6-hydroxy-1-naphthoic acid. Carboxylic acid, or 3-methyl-4-hydroxybenzoic acid, 3,
5-dimethyl-4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3,5-dimethoxy-4-hydroxybenzoic acid, 6-hydroxy-5 Methyl-2-naphthoic acid, 6-hydroxy-5-methoxy-2-naphthoic acid, 2-chloro-4-hydroxybenzoic acid, 3-chloro-4-hydroxybenzoic acid, 2,3-dichloro-4-hydroxybenzoic acid Acid, 3,5-dichloro-4-hydroxybenzoic acid, 2,5-dichloro-4-hydroxybenzoic acid, 3-bromo-4-hydroxybenzoic acid, 6-hydroxy-5-chloro-2-naphthoic acid, 6 -Hydroxy-
7-chloro-2-naphthoic acid, 6-hydroxy-5,7
And alkyl-, alkoxy-, or halogen-substituted aromatic hydroxycarboxylic acids such as -dichloro-2-naphthoic acid.

(C) As the aromatic diol, 4,4'-
Dihydroxybiphenyl, 3,3′-dihydroxybiphenyl, 4,4′-dihydroxyterphenyl, hydroquinone, resorcin, 2,6-naphthalenediol,
4'-dihydroxydiphenyl ether, bis (4-hydroxyphenoxy) ethane, 3,3'-dihydroxydiphenyl ether, 1,6-naphthalenediol, 2,2-
Bis (4-hydroxyphenyl) propane, aromatic diol such as bis (4-hydroxyphenyl) methane, or chlorohydroquinone, methylhydroquinone, tert-
Butylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4-
Alkyl, alkoxy or halogen-substituted aromatic diols such as chlororesorcin and 4-methylresorcin.

The (D ₁ ) aromatic dithiol includes benzene-1,4-dithiol, benzene-1,3-dithiol, 2,6-naphthalene-dithiol, and 2,7-naphthalene-dithiol. (D ₂ ) Examples of the aromatic thiophenol include 4-mercaptophenol, 3-mercaptophenol, and 6-mercaptophenol. (D ₃ ) Examples of the aromatic thiolcarboxylic acid include 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 6-mercapto-2-naphthoic acid, and 7-mercapto-2-naphthoic acid.

(E) Aromatic hydroxylamine and aromatic diamine compounds include 4-aminophenol, N
-Methyl-4-aminophenol, 1,4-phenylenediamine, N-methyl-1,4-phenylenediamine,
N, N'-dimethyl-1,4-phenylenediamine, 3-
Aminophenol, 3-methyl-4-aminopheno
2-chloro-4-aminophenol, 4-amino-
1-naphthol, 4-amino-4′-hydroxydiphenyl, 4-amino-4′-hydroxydiphenyl ether, 4-amino-4′-hydroxydiphenylmethane,
4-amino-4'-hydroxydiphenyl sulfide,
4,4'-diaminophenyl sulfide (thiodianiline), 4,4'-diaminodiphenyl sulfone, 2,5-diaminotoluene, 4,4'-ethylenedianiline, 4,4 '
-Diaminodiphenoxyethane, 4,4'-diaminodiphenylmethane (methylenedianiline), 4,4'-diaminodiphenylether (oxydianiline) and the like.

The thermotropic liquid crystal polyester used in the present invention can be produced from the above monomers by various ester forming methods such as a melt acidification method and a slurry polymerization method.

The weight average molecular weight of the thermotropic liquid crystal polyester used in the present invention is about 2,000 to 200,0.
00, preferably about 4,000 to 100,000.
The molecular weight can be measured, for example, by measuring terminal groups of the compressed film by infrared spectroscopy. GPC can also be used as a general measuring method performed in a solution state.

Among the thermotropic liquid crystal polyesters obtained from these monomers, an aromatic polyester which is a (co) polymer containing a monomer unit represented by the general formula 1 as an essential component is preferable. Particularly preferred are aromatic polyesters containing 5 mol% or more of the above monomer units.

[0015]

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One of the particularly preferred aromatic polyesters of the present invention is a polyester represented by Chemical Formula 2 having a repeating unit derived from each of three compounds of p-hydroxybenzoic acid, phthalic acid and dihydroxybiphenyl. The repeating unit derived from dihydroxybiphenyl of the polyester can be partially or entirely substituted by a repeating unit derived from dihydroxybenzene. Further, a polyester represented by Chemical Formula 3 having a repeating unit derived from two kinds of compounds, p-hydroxybenzoic acid and hydroxynaphthoic acid, is also preferable.

[0017]

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The thermotropic liquid crystal polyester of the present invention may be used alone or as a mixture of two or more.

The wholly aromatic polyester of the present invention has a melting completion temperature (T) determined by a capillary rheometer.
η ₂ , ° C) and the solidification onset temperature (Tη ₁ , ° C) (Tη ₂
It is important that (−Tη ₁ ) is in the range of 10 to 80 ° C. In a wholly aromatic polyester having a value of Tη ₂ −Tη ₁ of less than 10 ° C., the temperature range at which the viscosity is maintained at a low viscosity is too narrow, so that the injection is performed at a high pressure, which may cause damage to the electric / electronic element. It is not preferable. On the other hand, Tη
The wholly aromatic polyesters, such as the value of _{2 -Tη 1} exceeds 80 ° C., in order to solidification rate is too small, can be injected at a low injection pressure, results in leakage of molten resin from the mold cavity, This is not preferable because the generation of so-called burrs increases.

The melting point of the wholly aromatic polyester of the present invention is 300 to 4 in consideration of the balance between heat resistance and moldability.
It is in the range of 50C, preferably 300-420C. If the melting point is lower than 300 ° C., heat resistance as a sealing material is insufficient, which is not preferable. On the other hand, when the temperature exceeds 450 ° C., the melting point becomes too high, so that the resin is liable to be decomposed, and molding is difficult with a usual injection molding machine.

The melting point of the wholly aromatic polyester having optical anisotropy of the present invention, the melting completion temperature (Tη ₂ ) and the solidification onset temperature (Tη ₁ ) determined by a capillary rheometer are defined below. Things. <Melting point> DSC device (Seiko Electronics Co., Ltd., SSC
-5020) and completely melted to 10 ° C
The temperature of the sample cooled to room temperature at a rate of 20 ° C./min is raised at a rate of 20 ° C./min in a nitrogen atmosphere, and an endothermic peak is measured, which is defined as a melting point. <Solidification onset temperature (Tη ₁ ) determined by capillary rheometer> L / D = 40/1 (m) using a capillary rheometer (Model 2010, manufactured by Intesco Corporation).
m / mm), the temperature dependence of the apparent viscosity is measured at a shear rate of 100 sec ^-1 using a capillary with an inflow angle of 90 °. The measurement starts at a temperature 40 ° C. above the melting point,
After cooling at a constant speed of 4 ° C./min, the apparent viscosity-temperature curve was determined by finding the intersection of the tangents of the curve before and after the temperature at which the temperature dependency of the apparent viscosity (the gradient of the apparent viscosity / temperature) sharply increased, The temperature corresponding to this intersection is defined as the solidification start temperature (Tη ₁ ). <Same melting completion temperature (Tη ₂ )> The same apparatus and capillary as used in the measurement of the solidification start temperature (Tη ₁ ) are used, and the shear rate is also the same. The measurement is started at a temperature 50 ° C. lower than the melting point, and is heated at a constant speed of 4 ° C./min.
In the temperature curve, the intersection of the tangents of the curve before and after the temperature at which the temperature dependence of the apparent viscosity sharply decreases is determined, and the temperature corresponding to the intersection is defined as the melting completion temperature (Tη ₂ ).

The wholly aromatic polyester of the present invention can be produced according to a conventional polyester polycondensation method, and the production method is not particularly limited. A typical production method is, for example, the following (1) ) To (4). (1) A method of producing from a diacylated aromatic dihydroxy compound, an acylated aromatic hydroxycarboxylic acid and an aromatic dicarboxylic acid by a deacetic acid polycondensation reaction. (2) A method of producing from an aromatic dihydroxy compound, an aromatic hydroxycarboxylic acid and an aromatic dicarboxylic acid with acetic anhydride by a deacetic acid polycondensation reaction. (3) A method of producing from an aromatic dihydroxy compound, a diphenyl ester of an aromatic dicarboxylic acid, and a phenyl ester of an aromatic hydroxycarboxylic acid by a phenol removal polycondensation reaction. (4) reacting an aromatic hydroxycarboxylic acid and an aromatic dicarboxylic acid with a desired amount of diphenyl carbonate;
A method in which a carboxyl group is phenylesterified, an aromatic dihydroxy compound is added, and the mixture is produced by a dephenol polycondensation reaction.

For example, p-hydroxybenzoic acid (PHB)
A) 4,4′-Dihydroxybiphenyl (DHBP) and terephthalic acid (TPA) are charged into a reactor, acetic anhydride is added thereto, acetylation is performed under reflux of acetic anhydride, and then the temperature is raised to 250 to 350 ° C. Polyester is obtained by deacetic acid polycondensation while distilling acetic acid in a temperature range. The polymerization time can be selected in the range of 1 hour to several tens hours.

The catalyst used in the polycondensation reaction includes magnesium acetate, stannous acetate, tetrabutyl titanate,
Representative examples include lead acetate, sodium acetate, potassium acetate, antimony trioxide, and a metal catalyst, and are particularly effective for dephenol polycondensation.

In each of the above polycondensation methods, it is possible to use both melt polymerization and solid state polymerization. That is,
The degree of polymerization of a polymer that has been polycondensed by melt polymerization can be increased by solid phase polymerization. Known methods can be widely used for solid phase polymerization. For example, the heat treatment is performed by subjecting the polyester obtained by melt polymerization to a heat treatment in an inert atmosphere such as nitrogen at a temperature of 250 to 350 ° C. for 1 to 30 hours.

The polymerization vessel is not particularly limited, but may be a stirring apparatus used for a general high-viscosity reaction, such as an anchor-type stirrer, a multi-stage stirrer, a spiral band stirrer, a spiral shaft stirrer, and the like. , And a stirred tank type polymerization vessel equipped with a modified stirring equipment, and further selected from a Warner mixer, a Banbury mixer, a pony mixer, a Muller mixer, a roll mill, a continuously operable co-kneader, a hug mill, a gear compounder, etc. Is desirable.

The wholly aromatic polyester of the present invention obtained as described above can be used alone or by mixing several kinds of wholly aromatic polyesters. In any case, the type of the monomer to be copolymerized, the mixing ratio, the polymerization order, the catalyst, other polymerization conditions, and the like are appropriately selected, and for the obtained wholly aromatic polyester having optical melt anisotropy, the above-mentioned capillary is used. the difference of the melting completion temperature determined by rheometer and (T? ₂₎ and the solidification starting temperature _{(Tη 1) (Tη 2 -Tη} 1) it is imperative that polymerize to be in the range of 10 to 80 ° C.. In other words, Tη ₂ −Tη ₁
Using the value of 指標 as an index, the type, blending ratio,
The polymerization is performed by appropriately selecting the polymerization order, the catalyst, and other polymerization conditions.

As the encapsulating material, a wholly aromatic polyester having an optical melt anisotropy in which the value of Tη ₂ -Tη ₁ is in the range of 10 to 80 ° C. can be used alone. It can also be used as a composition containing 10 to 95% by weight of an inorganic filler. The inorganic filler is not particularly limited as long as the inorganic filler has a small coefficient of thermal expansion, a large thermal conductivity, and does not contain as much as possible a harmful substance that may interfere with the electrical operation of the electric / electronic component. . Preferably, for example, silica, alumina, titania, zirconia, titanium silicate, aluminum silicate,
Examples thereof include spherical and crushed particles such as lithium aluminum silicate, magnesium aluminum silicate, aluminum titanate, aluminum nitride, silicon nitride, talc, and mica; glass beads; and glass fibers. The particle size of the particulate filler or the diameter and the aspect ratio of the fibrous filler can be appropriately selected and used from an arbitrary range. These can be used alone or as a mixture of two or more. Of these, from the viewpoint of the balance between fluidity and heat resistance, silica,
It is preferable to use one or a mixture of two or more of alumina, glass beads, glass fiber, and talc as the filler.

In order to maintain good fluidity and heat resistance as a sealing material, the amount of the filler is preferably 10 to 95% by weight based on the whole resin composition, and 30 to 6% by weight.
A range of 5% by weight is particularly preferred. If it is less than 10% by weight,
Small increase in thermal expansion coefficient and thermal conductivity, while 95% by weight
When the ratio exceeds the above range, the fluidity of the resin is reduced and the surface state is deteriorated.

In order to mix the sealing material of the present invention and seal the electronic component with the sealing material, any known method can be employed. As a sealing method, for example, injection molding can be performed at a resin temperature of 290 ° C. to 370 ° C. and a mold temperature of 20 ° C. to 170 ° C., and a target electric / electronic component can be manufactured by, for example, insert molding.

[0031]

The present invention will be described below in detail with reference to examples. <Measurement Method> Each physical property value shown in Examples and Comparative Examples of the present invention was measured by the following methods. (Melting point): as described above. (Solidification onset temperature (Tη
₁ ) and melting completion temperature (Tη ₂ )): As described above. (Measurement of Deformation Amount of Coil Element): The molding material is subjected to sealing molding of the coil element at a predetermined cylinder temperature and a mold temperature of 30 ° C. by using an injection molding machine dedicated to insert (mold clamping force of 25 tons) and obtained sealing. The stop part is photographed by a soft X-ray projector, and the amount of deformation of the coil element is measured.

Example 1 In a polymerization tank having an anchor type stirring blade and having a small clearance between the tank wall of the polymerization tank and the stirring blade, p-
Hydroxybenzoic acid (PHBA) 1,449 g (10.5 g)
Mol) and 2-hydroxy-6-naphthoic acid (HN
A) 846 g (4.5 mol) is charged, and after vacuum drying,
1,720 g of acetic anhydride was added, and an acetylation reaction was carried out at 150 ° C. for 3 hours under acetic anhydride reflux. Then the temperature rises,
While distilling off acetic acid, the temperature was raised to 280 ° C. at a rate of 1 ° C./min and maintained for 45 minutes. Then up to 300 ° C at 1 ° C /
The temperature was raised at a rate of 1 minute and held for 30 minutes, and further raised to 320 ° C. at a rate of 1 ° C./minute and held. When the acetic acid distillate reached 93% of the theoretical distillate, 1.25 g of distearylpentaerythritol diphosphite was added. Thereafter, the torque increased, but the stirring power was increased and the stirring was maintained without stopping. When 3 hours had elapsed after distearyl pentaerythritol diphosphite was charged, the substance in the tank was taken out and found to be in the form of flakes. The melting point of the obtained resin is 280 ° C, the melting completion temperature is 305 ° C,
The solidification start temperature was 280 ° C, and the difference between the melting completion temperature and the solidification start temperature was 25 ° C. When melted at 290 ° C., it showed optical anisotropy. The above resin was mixed with 40% by weight of quartz glass powder, and kneaded and granulated by a twin screw extruder to obtain a pellet-shaped molding material. When an injection molding experiment was performed on the material at an injection temperature of 290 ° C., the deformation of the coil element was 0.4 mm.

Example 2 In a polymerization tank having an anchor type stirring blade and having a small clearance between the tank wall of the polymerization tank and the stirring blade, p-type water was added.
1,615 g (11.7 g) of hydroxybenzoic acid (PHBA)
Mol) and 2-hydroxy-6-naphthoic acid (HN
A) 620 g (3.3 mol) is charged, and after vacuum drying,
1,720 g of acetic anhydride was added, and an acetylation reaction was carried out at 150 ° C. for 3 hours under acetic anhydride reflux. Then the temperature rises,
While distilling off acetic acid, the temperature was raised to 280 ° C. at a rate of 1 ° C./min and maintained for 45 minutes. Then up to 300 ° C at 1 ° C /
The temperature was raised at a rate of 1 minute and held for 30 minutes, and further raised to 320 ° C. at a rate of 1 ° C./minute and held. When the acetic acid distillate reached 93% of the theoretical distillate, 1.25 g of distearylpentaerythritol diphosphite was added. Thereafter, the torque increased, but the stirring power was increased and the stirring was maintained without stopping. When 3 hours had elapsed after distearyl pentaerythritol diphosphite was charged, the substance in the tank was taken out and found to be in the form of flakes. The melting point of the obtained resin is 332 ° C, the melting completion temperature is 356 ° C,
The solidification start temperature was 330 ° C, and the difference between the melting completion temperature and the solidification start temperature was 26 ° C. When melted at 340 ° C., it showed optical anisotropy. The above resin was mixed with 40% by weight of quartz glass powder, and kneaded and granulated by a twin screw extruder to obtain a pellet-shaped molding material. When an injection molding experiment was performed on the material at an injection temperature of 340 ° C., the deformation of the coil element was 0.3 mm.

Comparative Example 1 A polymer layer having an anchor type stirring blade and having a small clearance between the tank wall of the polymerization tank and the stirring blade was p-type.
1,035 g (7.5 mol) of hydroxybenzoic acid (PHBA), 4,4′-dihydroxybiphenyl (DHBP) 6
98 g (3.75 mol), terephthalic acid (TPA) 57
3 g (3.45 mol) and isophthalic acid (IPA) 5
After adding 0 g (0.3 mol) and drying in vacuo, 1,720 g of acetic anhydride was added, and the acetylation reaction was carried out at 150 ° C. for 3 hours under acetic anhydride reflux. Thereafter, the temperature was raised, and the temperature was raised to 280 ° C. at a rate of 1 ° C./min while evaporating acetic acid, and held for 45 minutes. Then, the temperature was raised to 300 ° C. at a rate of 1 ° C./min and held for 30 minutes, and further raised to 320 ° C. at a rate of 1 ° C./min. When the acetic acid distillate reached 93% of the theoretical distillate, 1.25 g of distearylpentaerythritol diphosphite was added. Thereafter, the torque increased, but the stirring power was increased and the stirring was maintained without stopping. When 3 hours had elapsed after distearyl pentaerythritol diphosphite was charged, the substance in the tank was taken out and found to be in the form of flakes. The obtained flake-like substance is pulverized by a pulverizer,
Heat treatment was performed at 80 ° C. for 2 hours, at 300 ° C. for 2 hours, and further at 330 ° C. for 6 hours. Melting point of resin after heat treatment is 401
° C, melting completion temperature is 415 ° C, solidification start temperature is 409 ° C
The difference between the melting completion temperature and the solidification start temperature was 6 ° C. When melted at 411 ° C., it showed optical anisotropy. The above resin is mixed with 40% by weight of quartz glass powder,
The mixture was kneaded and granulated by a twin-screw extruder to obtain a pellet-shaped molding material. When an injection molding experiment was performed on the material at an injection temperature of 411 ° C., the deformation of the coil element was 1.5 mm.

<Comparative Example 2> p-polymer was added to a polymerization tank having an anchor type stirring blade and having a small clearance between the tank wall of the polymerization tank and the stirring blade.
Hydroxybenzoic acid (PHBA) 1,242 g (9.0 mol), 4,4′-dihydroxybiphenyl (DHBP) 5
58 g (3.0 mol), terephthalic acid (TPA) 448
g (2.7 mol) and 50 g of isophthalic acid (IPA)
(0.3 mol), dried under vacuum, and then dried with 1.7 mL of acetic anhydride.
20 g was added, and an acetylation reaction was carried out at 150 ° C. for 3 hours under acetic anhydride reflux. Thereafter, the temperature was raised, and the temperature was raised to 280 ° C. at a rate of 1 ° C./min while evaporating acetic acid, and held for 45 minutes. Then, the temperature was raised to 300 ° C. at a rate of 1 ° C./min and held for 30 minutes, and further raised to 320 ° C. at a rate of 1 ° C./min. Acetic acid distillate is 93% of theoretical distillate
Was reached, 1.25 g of distearylpentaerythritol diphosphite were charged. Thereafter, the torque increased, but the stirring power was increased and the stirring was maintained without stopping. When 3 hours had elapsed after distearyl pentaerythritol diphosphite was charged, the substance in the tank was taken out and found to be in the form of flakes. The obtained flake-like substance is pulverized by a pulverizer, and heated at 280 ° C. under a nitrogen atmosphere.
For 2 hours, at 300 ° C. for 2 hours, and further at 330 ° C. for 6 hours. The melting point of the resin after the heat treatment was 390 ° C., the melting completion temperature was 392 ° C., the solidification start temperature was 390 ° C., and the difference between the melting completion temperature and the solidification start temperature was 2 ° C.
When melted at 400 ° C., it showed optical anisotropy.
The above resin was mixed with 40% by weight of quartz glass powder, and kneaded and granulated by a twin screw extruder to obtain a pellet-shaped molding material. When an injection molding experiment was performed on the material at an injection temperature of 400 ° C., the deformation of the coil element was 1.8 mm.

[0036]

The wholly aromatic polyester having optical melt anisotropy can lower the injection molding pressure, and if it is used for encapsulation molding, damage to the sealed electric / electronic element will occur. Can be reduced.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 63/00-63/91 C08G 67/00-67/03

Claims (3)

(57) [Claims] 1. A melting completion temperature (Tη ₂ , ° C.) and a solidification start temperature (T) determined by a capillary rheometer.
η ₁ , ° C.) (T η ₂ −T η ₁ ) is in the range of 10 to 80 ° C. and is made of a wholly aromatic polyester having an optical melt anisotropy. . 2. The melting point of the wholly aromatic polyester is 3
The temperature is in the range of 00 to 450 ° C.
The encapsulating material for electric and electronic parts according to 1. 3. A sealing material for electric and electronic parts comprising the wholly aromatic polyester according to claim 1 and 10 to 95% by weight of an inorganic filler based on the whole composition.