JP4878492B2 - Thermotropic liquid crystal polyester resin composition and electric / electronic component - Google Patents

Description

  The present invention relates to a thermotropic liquid crystal polyester resin composition having an extremely small amount of outgas generation, particularly an extremely small amount of corrosive gas generation under a high temperature environment such as solder reflow, and a structure obtained from the resin composition The present invention relates to an electric / electronic component having a member.

  A resin composition containing a thermotropic liquid crystalline polyester and an inorganic filler is used as a structural member in the electric and electronic parts industry, because of its excellent heat resistance in a high temperature environment such as solder reflow in addition to excellent molding characteristics. Yes. However, even if the heat resistance as a material of the resin composition itself is excellent, the contained volatile organic matter may be released as a gas (outgas) outside the system in these environments. If the gas is corrosive to metal, it may adversely affect the function of the metal part in the electric / electronic part.

Typical examples of metal corrosive outgas are acetic acid and phenol, but some proposals have been made for the purpose of reducing the amount of these emissions (for example, see Patent Documents 1 to 5).
JP 2000-344879 A JP-A-3-203925 JP 2000-34015 A JP-A-8-333505 JP 2003-277517 A

  However, these proposals are the regulation of the amount of acetic anhydride added in the polymerization process (Patent Document 1), the specification of the terminal blocking group (Patent Document 2), the addition of a specific phosphite (Patent Document 3), the specific Addition of adsorbent (hydrotalcite) (Patent Document 4) and melt-kneading with a specific kneader (Patent Document 5), etc., all of which are conventional processes, addition of a new compound, adoption of a new kneading apparatus, etc. As a result, although outgassing suppression can be obtained, it may adversely affect some of the advantages of using a resin composition containing a thermotropic liquid crystal polyester. Also, additional costs are required economically.

  An object of the present invention is to provide a resin composition in which gas emission of volatile organic substances is suppressed by an extremely simple and efficient method.

  The first aspect of the present invention relates to a thermotropic liquid crystal polyester resin composition obtained by melting and kneading 5 to 100 parts by mass of talc and / or glass-based filler surface-treated with aluminum oxide in 100 parts by mass of thermotropic liquid crystal polyester. Is.

  In addition, according to a second aspect of the present invention, in the resin composition, the talc and / or glass-based filler surface-treated with the aluminum oxide has an aluminum oxide content of 1 to 100 parts by mass of talc and / or glass-based filler. The surface treatment is performed in the range of 15 parts by mass.

  Furthermore, the present invention relates to an electric / electronic component comprising a structural member obtained from either the first or second resin composition of the present invention.

  The present invention was made by paying attention to the interfacial interaction during melt-kneading between the inorganic filler in the composition and the thermotropic liquid crystalline polyester, without substantial modification of the polymerization process and the melt-kneading process. A resin composition in which the release of metal corrosive gas is suppressed while maintaining the excellent heat resistance and moldability of the thermotropic liquid crystal polymer can be obtained.

(Thermotropic liquid crystal polyester)
The thermotropic liquid crystal polymer according to the present invention is not particularly limited, but when used as a constituent material of an electric / electronic component to be surface-mounted in a solder reflow process or the like, the melting point is 320 ° C. or higher from the viewpoint of heat resistance. A wholly aromatic thermotropic liquid crystal polyester is preferred. In addition, a high melting point is inevitably high in terms of the melt-kneading temperature, and is preferable from the viewpoint of activating the interfacial interaction between the thermotropic liquid crystal polyester and the filler.

  In order to obtain a wholly aromatic thermotropic liquid crystal polyester having a melting point of 320 ° C. or higher, p-hydroxybenzoic acid may be used in an amount of 40 mol% or more as a raw material monomer. Other than this, known aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, and aromatic diols can be used in any combination. For example, polyesters obtained only from aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and 2-hydroxy-6-naphthoic acid, and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid. Preferable examples include acid and / or liquid crystalline polyester obtained from an aromatic dihydroxy compound such as hydroquinone, resorcin, 4,4′-dihydroxydiphenyl, and 2,6-dihydroxynaphthalene.

  Particularly preferably, p-hydroxybenzoic acid (I), terephthalic acid (II), 4,4′-dihydroxybiphenyl (III) (including these derivatives) is contained in an amount of 80 to 100 mol% (provided that (I) and (II) is 60 mol% or more), and (I) (II) (III) and any other aromatic compound capable of decondensation reaction is obtained by polycondensation in an amount of 0 to 20 mol%. A wholly aromatic thermotropic liquid crystal polyester.

  In the production of wholly aromatic thermotropic liquid crystalline polyesters, in order to shorten the melt polycondensation time, reduce the influence of thermal history during the process, and suppress the formation of low molecular weight compounds as volatile components, the hydroxyl groups of the above monomers It is preferable to carry out melt polycondensation after acetylation of the compound in advance. Furthermore, in order to simplify the process, acetylation is preferably performed by supplying acetic anhydride to the monomer in the reaction vessel. This acetylation step is preferably performed using the same reaction vessel as the melt polycondensation step. That is, it is preferable to carry out an acetylation reaction with a raw material monomer and acetic anhydride in a reaction vessel, and then proceed to a polycondensation reaction by raising the temperature after completion of the reaction.

  A melt polycondensation reaction is performed with a deacetic acid reaction of the acetylated monomer. The reaction vessel is preferably used using a reaction vessel equipped with monomer supply means, acetic acid discharge means, molten polyester take-out means and stirring means. Such a reaction vessel (polycondensation apparatus) can be appropriately selected from known ones. The polymerization temperature is preferably 150 ° C to 350 ° C. After completion of the acetylation reaction, the temperature is raised to the polymerization start temperature to start polycondensation, the temperature is raised in the range of 0.1 ° C./min to 2 ° C./min, and the final temperature is raised to 280 to 350 ° C. Is preferred. As the catalyst for the polycondensation reaction, compounds such as Ge, Sn, Ti, Sb, Co, Mn, and Mg can be used. The polycondensation temperature rises as the melting temperature of the produced polymer rises as the polycondensation proceeds. The melt polycondensation reaction product subjected to the solid phase polycondensation step is a wholly aromatic thermotropic liquid crystal polyester having a low polymerization degree, and its pour point is preferably 200 ° C. or higher, more preferably 220 ° C. to 330 ° C.

  In the melt polycondensation, when the pour point reaches 200 ° C. or higher, preferably 220 ° C. to 330 ° C., the fully aromatic thermotropic liquid crystalline polyester having a low polymerization degree is withdrawn from the polymerization tank in a molten state, and a steel belt or a drum cooler. Etc., cool and solidify.

  Next, the solidified wholly aromatic thermotropic liquid crystal polyester having a low polymerization degree is pulverized to a size suitable for the subsequent solid phase polycondensation. The crushing method is not particularly limited. For example, impact mills such as feather mill, Victor mill, Coroplex, Pulverizer, Contraplex, scroll mill, ACM pulverizer, etc. manufactured by Hosokawa Micron Co., Ltd. A roll granulator or the like. Particularly preferred is a feather mill manufactured by Hosokawa Micron. In the present invention, the particle size of the pulverized material is not particularly limited, but it is preferably in the range of 4 mesh to 2000 mesh not passing through an industrial sieve (Tyler mesh), preferably 5 mesh to 2000 mesh (0.01 to 4 mm). More preferably, it is most preferably 9 mesh to 1450 mesh (0.02 to 2 mm).

  Next, the pulverized product obtained in the pulverization step is subjected to a solid phase polycondensation step to perform solid phase polycondensation. There is no restriction | limiting in particular in the apparatus used for a solid-phase polycondensation process, and operating conditions, A well-known apparatus and method can be used.

(Inorganic filler)
As the inorganic filler to be blended with the thermotropic liquid crystal polymer, talc and / or glass-based filler surface-treated with aluminum oxide is used. As the talc and glass-based filler, those used for improving the heat resistance, rigidity and molding processability of the thermotropic liquid crystal polymer, particularly the molding processability of injection molding, can be preferably used. Glass-based fillers include glass fibers (including milled fibers) having an aspect ratio of 3 or more, glass flakes, and the like. These fillers are plate-like or fiber-like, and unlike spherical fillers having an aspect ratio of about 1 such as calcium carbonate and glass balloon, in the injection-molded composition, they are in the same direction as the resin molecules. As a result, the moldability can be imparted without impairing the heat resistance and rigidity inherent to the thermotropic liquid crystal polymer.

(surface treatment)
The surface treatment method of the talc and / or glass filler of the present invention with aluminum oxide (including hydrate) is not particularly limited, and a known method can be used. For example, after a predetermined amount of aluminum oxide or aluminum oxide hydrate is added to water to form a slurry (for example, the method described in JP-A Nos. 55-154317 and 3-275768) or fine particles of aluminum oxide are added in water The surface treatment is performed by fixing aluminum oxide (including hydrate) to the surface of the talc and / or glass-based filler after sol-solation with (for example, the method described in Japanese Patent Application No. 7-224049). It can be carried out.

  Regarding the mechanism for suppressing the release of volatile organic substances from the thermotropic liquid crystal polyester as outgas by surface treatment with aluminum oxide, the present inventors have the characteristics of aluminum oxide, namely the adsorption function and amphoteric (acidic and amphoteric). (Alkaline), is considered to be involved. In other words, the aluminum oxide fixed in the form of a film on the surface of talc and / or glass filler and the thermotropic liquid crystal polymer efficiently contact (melt knead) under high temperature conditions, so that the volatility in the liquid crystal polymer is increased. It is thought that the compound is adsorbed.

  Therefore, when the effect of the present invention includes the step of carrying out melt polycondensation using an acetylated derivative of a monomer, the acetylation of the monomer and the melt polycondensation using the resulting acetylated derivative are the same reaction. The effect is most exerted when there is a high possibility that the acetic acid-based compound remains, for example, in a tank.

  In this invention, it is preferable to perform a surface treatment in the range of 1-15 mass parts of aluminum oxide with respect to 100 mass parts of talc or a glass-type filler. When the amount of aluminum oxide is less than 1 part by mass, the effect of covering the surface of the filler is insufficient, and the adsorption effect cannot be sufficiently exhibited. When the amount exceeds 15 parts by mass, a handling problem may occur due to aggregation or the like. . A particularly preferable range is 3 to 10 parts by mass.

  In the present invention, 5 to 150 parts by mass of the surface-treated filler is used with respect to 100 parts by mass of the thermotropic liquid crystal polyester. If the amount is less than 5 parts by mass, the suppression of the generation of corrosive gas may not be sufficient. If the amount exceeds 150 parts by mass, the moldability may be deteriorated.

  The equipment used for the melt-kneading step in the present invention is not particularly limited, and a single-screw kneader, a twin-screw kneader, a Banbury mixer, a pressure kneader, etc. can be used, but the surface treatment was performed with the thermotropic liquid crystal polyester. From the viewpoint of improving the interaction with the filler, a twin-screw kneader that is easy to efficiently and uniformly melt knead is preferable.

  In addition to talc and / or glass fillers surface-treated with thermotropic liquid crystalline polyester and aluminum oxide, other known inorganic fillers and organic fillers are impaired in the resin composition of the present invention. It is possible to add in the range which is not. These may be used alone or in combination of two or more.

(Manufacture of thermotropic liquid crystal polyester)
After using SUS316 as a material and a 6 L polymerization tank (manufactured by Nitto High Pressure Co., Ltd.) having a double helical stirring blade, the pressure in the polymerization tank was reduced and nitrogen injection was repeated 5 times, and then the Ueno Pharmaceutical was replaced. P-Hydroxybenzoic acid (HBA) 1,330.10 g (9.63 mol) manufactured by Co., Ltd., 79.99 g (0.4815 mol) of isophthalic acid (IPA) manufactured by AG International, Mitsui Petrochemical Industries ( 453.29 g (2.7285 mol) of terephthalic acid (TPA) manufactured by the same company, 59.73 g (3.21 mol) of p, p′-biphenol (BP) manufactured by Honshu Chemical Industry Co., Ltd., and Tokyo Chemical as a catalyst 0.35 g of magnesium acetate manufactured by the company was charged, and the monomer in the polymerization tank was stirred and mixed with the stirring blade rotating at 50 rpm.
Next, 1,769.22 g (17.33 mol) of acetic anhydride manufactured by Chisso Corporation was added, the temperature was increased to 150 ° C. over 1 hour with the rotation speed of the stirring blade being 100 rpm, and the acetic anhydride was refluxed. The acetylation reaction was performed for 2 hours. After completion of acetylation, acetic acid was distilled off and the temperature was raised at a rate of 0.5 ° C./min. The polymer taken out was cooled and solidified, then pulverized to 1 mm or less by a pulverizer, and solid phase polymerization was performed using a solid phase polymerization apparatus (Asahi Glass Co., Ltd.) having a cylindrical rotary reactor. That is, the pulverized polymer was charged into the reactor, nitrogen was circulated at a flow rate of 1 liter / min, and the temperature was raised to 280 ° C. over 2 hours at a rotation speed of 20 rpm. It was kept at 280 ° C. for 1 hour, heated to 300 ° C. in 30 minutes and kept for 4 hours, and then cooled to room temperature in 1 hour to obtain a polymer. It was 376 degreeC when melting | fusing point of the obtained polymer was measured by DSC. The apparent viscosity at 410 ° C. was 1,110 poise. (Hereinafter, the thermotropic liquid crystal polyester obtained by the method is referred to as “liquid crystal polyester A”.)

(Surface treatment talc)
In a 15-liter separable flask equipped with a stirrer, a thermometer and a condenser, 9000 g of water, alumina sol (trade name “520” manufactured by Nissan Chemical Industries, Ltd., aluminum oxide concentration: 20.9%, particle size: 10 to 20 nm ) 140 g, commercially available talc (trade name “MSKY” manufactured by Nippon Talc Co., Ltd., average particle size 24 μm, aspect ratio = 7) (hereinafter referred to as “untreated talc”) 1000 g was added, and 85 ° C. for 2 hours. Heat mixing was performed. After the stirring was stopped, the cake-like talc was obtained by standing still and filtering for 30 minutes, vacuum-dried at 200 ° C. for 20 hours as it was, cooled to room temperature, and then crushed to obtain “surface-treated talc”.

(Surface-treated glass fiber)
Chopped glass fiber (trade name “PX-1” manufactured by Asahi Fiber Glass Co., Ltd., average fiber length: 3.5 mm, average fiber diameter: 10 μm, aspect ratio = 350) (hereinafter referred to as “untreated glass fiber”). ) Was used in the same manner as in the case of talc (but in this case without crushing) to obtain “surface-treated glass fiber”.

(Manufacture of resin composition)
Liquid crystal polyester A, untreated talc, surface-treated talc, untreated glass fiber, and surface-treated glass fiber in the amounts shown in Table 1 were mixed, and the cylinders were mixed with a 30 mmφ twin-screw extruder (manufactured by Ikekai Steel Co., Ltd.). Pellets were obtained by melt-kneading at a maximum temperature of 430 ° C.

(Measurement of outgas amount)
The obtained pellets were pulverized by a 1 mmφ mesh pulverizer, and the obtained pulverized product was sealed in a 20 ml vial, followed by heat treatment at 150 ° C. for 24 hours. The generated acetic acid and phenol gases were quantified by gas chromatography (HP6890) connected to a headspace sampler (HP7694) manufactured by Hewlett Packard. The column used was G-100 (40 m) manufactured by the Chemicals Inspection Association. Other conditions were an initial temperature of 45 ° C., a heating rate of 20 ° C./min, a final temperature of 280 ° C., a helium pressure of 8.3 psi, and a split ratio of 2 The measurement was performed using an FID detector as 0.0.
The results are shown in Table 1 in contrast to the composition.

  As shown in Table 1, the resin composition (Examples 1 to 5) of the present invention containing surface-treated talc and / or surface-treated glass fiber and thermotropic liquid crystal polyester was used for surface untreated talc and / or surface untreated. It can be seen that the amount of acetic acid and phenol gas generated is very small compared to the resin composition containing glass fibers.

  The resin composition according to the present invention generates very little corrosive gas, and is particularly suitable for use as a constituent member of electric and electronic parts.

Claims (3)

  A thermotropic liquid crystal polyester resin composition obtained by melting and kneading 5 to 100 parts by mass of talc and / or glass-based filler surface-treated with aluminum oxide in 100 parts by mass of thermotropic liquid crystal polyester.   The talc and / or glass-based filler surface-treated with the aluminum oxide is a surface-treated in the range of 1 to 15 parts by mass of aluminum oxide with respect to 100 parts by mass of talc and / or glass-based filler. The resin composition according to claim 1, wherein   An electrical / electronic component comprising a structural member obtained from the resin composition according to claim 1.