JP4945163B2 - 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 that generates a very small amount of outgas, particularly a corrosive gas generated under a high temperature environment such as solder reflow, and a structural member obtained from the resin composition It is related with the electrical and electronic component which comprises.

  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 of the present invention comprises 100 parts by weight of thermotropic liquid crystalline polyester, 0.1 to 5 parts by weight of metal oxide fine particles having an average particle size of 100 nm or less and forming a sol in the solution, and 0 to 150 parts by weight of filler. The present invention relates to a thermotropic liquid crystal polyester resin composition obtained by melt-kneading.

According to a second aspect of the present invention, in the first resin composition of the present invention, the metal oxide fine particles are aluminum oxide.

A third aspect of the present invention relates to an electric / electronic component comprising a structural member obtained from the first or second resin composition of the present invention.

  The present invention provides excellent heat resistance and moldability of the thermotropic liquid crystal polyester without substantial modification of the polymerization process and the melt kneading process when fine particles having a specific adsorptive function are melt-kneaded into the thermotropic liquid crystal polyester. While maintaining the above, it is possible to obtain a resin composition in which metal corrosive gas release is suppressed.

(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.

(Metal oxide fine particles)
The metal oxide fine particles blended in the thermotropic liquid crystal polyester has an average particle size of 100 nm or less. If it exceeds 100 nm, the efficiency of the surface treatment decreases, which is not preferable. A preferable average particle diameter is 5 to 30 nm. Preferred are metal oxide fine particles such as rods, granules, plates, feathers and the like having a size of a nanometer unit so as to form a sol in a solution. These are available from the market in sol form from the market. For example, it is contained in silica sol, alumina sol, and antimony oxide sol sold by Nissan Chemical Industries.

  Regarding the mechanism for suppressing the release of volatile organic substances from the thermotropic liquid crystal polyester as outgas by the addition of the metal oxide fine particles of the present invention, the present inventors have heat resistance that can withstand the processing temperature of the thermotropic liquid crystal polyester. It is considered that the adsorption function is based on a large surface area per unit volume of the metal oxide.

  In particular, when the metal fine particle is aluminum oxide, due to its amphoteric (acidic and alkaline) characteristics, when it includes a step of performing melt polycondensation using an acetylated derivative of the monomer, the acetylation of the monomer and the result The effect is most exhibited when there is a high possibility that an acetic acid-based compound remains, such as when melt polycondensation using the obtained acetylated derivative is carried out in the same reaction vessel.

In the present invention, 0.1 to 5 parts by mass of metal oxide fine particles that form a sol in a solution is added to 100 parts by mass of thermotropic liquid crystal polyester. If the metal oxide fine particles are less than 0.1 parts by mass, the adsorption effect cannot be sufficiently exerted, and if it exceeds 5 parts by mass, a problem of condensation between the metal oxides may occur . Good preferable range is from 0.2 to 2 parts by weight.

  There are no particular limitations on the equipment used in the melt-kneading step in the present invention, and a single-screw kneader, a twin-screw kneader, a Banbury mixer, a pressure kneader, etc. can be used, but it is efficient from the viewpoint of improving the interaction. In addition, a twin-screw kneader that facilitates uniform melt-kneading is preferable.

  In the resin composition of the present invention, in addition to the thermotropic liquid crystal polyester and the metal oxide fine particles, other known inorganic fillers and organic fillers are within a range that does not impair the effects of the present invention, preferably 0 to 150 parts by mass. , Can be added. 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, and then pulverized to 1 mm or less with a pulverizer, and solid phase polymerization was performed with 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”.)

(1) The product name “520” (aluminum oxide concentration: 20.9%, particle size: 10 to 20 nm) manufactured by Nissan Chemical Industries, Ltd. was used as the alumina sol.
(2) The product name “Snowtex C” (silicon oxide concentration: 20 to 21%, particle size: 10 to 20 nm) manufactured by Nissan Chemical Industries, Ltd. was used as the silica hydrosol.
(3) Chopped glass fiber manufactured by Asahi Fiber Glass Co., Ltd., trade name “PX-1” (average fiber length: 3.5 mm, average fiber diameter: 10 μm, aspect ratio = 350) was used as the glass fiber. .
(4) As aluminum oxide having an average particle size of 80 μm, activated alumina manufactured by Nichikin Kin Co., Ltd., trade name “AA100-100” was used.
(5) As silicon oxide having an average particle size of 50 μm, fine silica manufactured by Asahi Glass S-Tech Co., Ltd., trade name “MS GEL” was used.

(Manufacture of resin composition)
Using liquid crystal polyester A, alumina sol, silica hydrosol and chopped glass fiber, compositions (Examples 1 to 4 and Comparative Examples 1 to 3) having the compositions shown in Table 1 were obtained by the following method.

  In a 15-liter separable flask equipped with a stirrer and a thermometer, 1000 g of “Liquid Crystal A” was added, 25 g of “Alumina Sol” was added, and the mixture was stirred and mixed at 85 ° C. for 2 times. Then, after vacuum-drying at 200 degreeC for 20 hours and cooling to room temperature, the composition ("Composition 1") which consists of 0.5 mass part of fine particle aluminum oxide and 100 mass parts of liquid crystal polymer A was obtained.

  Instead of “alumina sol” of composition 1, a “silica hydrosol” is used to obtain a composition (“composition 2”) comprising 0.5 parts by mass of fine-particle silicon oxide and 100 parts by mass of liquid crystal polymer A. It was.

  In 100.5 parts by mass of Composition 1, 30 parts by mass (Example 1), 60 parts by mass (Example 2) and 90 parts by mass (Example 3) of “glass fiber” are 100.5 parts by mass. 30 parts by weight of “glass fiber” (Example 4) was mixed with composition 2, and melt-kneaded at a maximum temperature of 430 ° C. of the cylinder with a 30 mmφ twin-screw extruder (manufactured by Ikekai Steel Co., Ltd.). Obtained.

  Further, as Comparative Examples 1 to 3, the ratio of “Liquid Polyester A” in 100 parts by mass with “aluminum oxide having an average particle size of 80 μm”, “silicon oxide having an average particle size of 50 μm”, and “glass fiber” shown in Table 1. Then, the mixture was melt-kneaded in the same manner as in Example to obtain pellets.

(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 compositions (Examples 1 to 4) of the present invention containing metal oxide fine particles such as fine particle aluminum oxide or fine particle silicon oxide and thermotropic liquid crystal polyester contain metal oxide fine particles. It can be seen that the amount of acetic acid and phenol gas generated is extremely small as compared with the resin composition without.

  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 100 parts by mass, an average particle diameter of 100 nm or less , and 0.1 to 5 parts by mass of metal oxide fine particles forming a sol in a solution and 0 to 150 parts by mass of a filler are melt-kneaded. Liquid crystal polyester resin composition. The resin composition according to claim 1, wherein the metal oxide fine particles are aluminum oxide. Electrical and electronic parts which is characterized by comprising a structural member obtained from the resin composition according to claim 1 or claim 2.