TW201546112A - Wholly aromatic liquid crystalline polyester resin and injection molded body of said resin composition - Google Patents

Abstract

The present invention addresses the problem of providing a wholly aromatic liquid crystalline polyester resin which has excellent surface mount technology (SMT) heat resistance and thin wall moldability and which is used for an injection molded body that can be used for electronic parts and the like having a thin wall portion of 0.03 mm to 0.15 mm. The present invention is achieved by a wholly aromatic liquid crystalline polyester which has a melting point of 320 DEG C or higher, and includes, as constitutional units, chemical formula (1) represented by p-hydroxybenzoic acid, chemical formula (2), (3), or (4) represented by hydroquinone, p-dihydroxybiphenyl, or 2,7-dihydroxynaphthalene, respectively, and chemical formula (5) represented by terephthalic acid, with the composition, in mol% units, being 20≤composition of chemical formula (1)≤70, 15≤ composition of chemical formula (2)+chemical formula (3)+chemical formula (4)≤40, provided that [chemical formula (2)+chemical formula (3)]≥chemical formula (4), and 15≤chemical formula (5)≤40.

Description

Injection molded body of wholly aromatic liquid crystal polyester resin and resin composition thereof

The wholly aromatic liquid crystal polyester resin is used as an injection molding material for various electronic component structures. In recent years, the intensive or miniaturization of the functions of these electronic components has led to an endless progress in thin meat. At the same time, in order to maintain production efficiency, it is of course required to have heat resistance corresponding to surface adhesion (SMT) (so-called solder heat resistance, the present invention and others believe that according to ISO11357-3, ASTM D3418, with a melting point of 320 ° C or higher as a standard) .

The present invention relates to a wholly aromatic liquid crystal polyester resin suitable for thin meated electronic parts corresponding to such high-level requirements in recent years, and a thin meat structure portion having a thickness of 0.03 mm to 0.15 mm obtained by the injection molded body of the resin composition. Electronic parts.

The wholly aromatic liquid crystal polyester resin composition containing various inorganic fillers is excellent in surface adhesion (SMT) heat resistance and thin moldability, and is used as an injection molding material for various electronic parts.

However, as in recent years, when various electronic parts contain a thin meat portion of 0.03 mm to 0.15 mm, even a wholly aromatic liquid crystal polyester resin composition, so-called short shots (generating unfilled portions in the cavity) occur. The reason for the problem is that it is a flow ‧ filled in the cavity, the temperature drop caused by the wall of the mold.

One of the solutions to this problem should be a review of the constituent monomers of the wholly aromatic liquid crystal polyester. In other words, the classification of aromatic hydroxycarboxylic acids, aromatic diols, and aromatic dicarboxylic acids is reviewed, and the "selection of monomer types" and "relationship between monomers" are reviewed.

The inventors reviewed the effective use of 2,7-dihydroxynaphthalene. The use of 2,7-dihydroxynaphthalene as a wholly aromatic liquid crystal polyester resin monomer is described in Patent Document 1 and Patent Document 2. However, Patent Document 1 does not contain a monomer of a dihydroxybiphenyl (chemical formula (3)) structure described later; and Patent Document 2 discloses a monomer composition and composition ratio common to the present application, but The purpose of adding 2,7-dihydroxynaphthalene is different from that of the present application, and the purpose thereof is to produce a wholly aromatic polyester constituting a yarn-forming liquid crystal melt at 300 ° C or lower, without revealing any specific order for solving the above problems. A method of using a wholly aromatic liquid crystal polyester resin composed of a body.

Further, Patent Document 3 discloses a liquid crystal polyester resin composition which can be used for a surface-adhesive electronic component such as a connector, and which can produce a molded article having good thin moldability, which can be carried out using a 0.1 mm thick mold. The connector is injection molded, but the composition of the liquid crystal polyester resin is different.

Advanced technical literature

Patent literature

[Patent Document 1] Japanese Patent Laid-Open Publication No. SHO 60-38426

[Patent Document 2] Japanese Patent Laid-Open Publication No. SHO 60-104123

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2010-138228

Problem to be solved by the invention

It is an object of the present invention to provide a wholly aromatic liquid crystal polyester comprising a 2,7-dihydroxynaphthalene comprising a corresponding surface adhesion (including a wholly aromatic liquid crystal polyester composition) SMT) is an injection molding material such as heat resistance and an electronic component having a plurality of thin portions of 0.03 mm to 0.15 mm.

Technical means of solving problems

In order to achieve the above object, the inventors of the present invention conducted a review and found that specific "aromatic hydroxycarboxylic acid", "aromatic diol (including 2,7-dihydroxynaphthalene)", and "aromatic dicarboxylic acid" were selected. And in a specific molar ratio range, the polycondensation reaction is carried out to obtain a wholly aromatic liquid crystal polyester, and a wholly aromatic liquid crystal polyester resin composition containing the same is injection-molded, and a corresponding one can be obtained. The injection molding of an electronic component such as a thin portion of 0.03 mm to 0.15 mm at the same time as the heat resistance of the surface adhesion (SMT) is completed.

A first aspect of the present invention relates to a wholly aromatic liquid crystal polyester which comprises a total of 100 mole % of an aromatic hydroxycarboxylic acid, an aromatic diol, and an aromatic dicarboxylic acid (including the derivatives) Polycondensed; the constituent unit of aromatic hydroxycarboxylic acid is composed of chemical formula (1);

[Chemical 1]

The constituent unit of the aromatic diol is composed of the chemical formula (2), the chemical formula (3) and the chemical formula (4);
[Chemical 2]

[Chemical 3]

[Chemical 4]

The constituent unit of the aromatic dicarboxylic acid is composed of the chemical formula (5);

[Chemical 5]

And 20 mol % ≦ chemical formula (1) composition ≦ 70 mol%;

15 mol % ≦ [chemical formula (2) composition + chemical formula (3) composition + chemical formula (4) composition] ≦ 40 mol%;

Wherein [chemical formula (2) composition + chemical formula (3) composition] (mol%) ≧ chemical formula (4) composition (mol%);

Here, the composition of each repeating unit of the chemical formulas (2), (3), and (4) is >0 mol%;

15 mole % ≦ chemical formula (5) composition ≦ 40 mol%; and

The melting point of the wholly aromatic liquid crystal polyester resin is 320 ° C or higher.

According to a second aspect of the present invention, there is provided an injection molded article obtained by injection molding a resin composition comprising the wholly aromatic liquid crystal polyester according to the first aspect of the present invention, which has a thickness of 0.03 to 0.15 mm. Thick meat.

A third aspect of the invention relates to an electronic component using the injection molded body as described in the second aspect of the invention.

A fourth aspect of the present invention relates to a method for producing a wholly aromatic liquid crystal polyester, which comprises polycondensing a total of 100 mol% of an aromatic hydroxycarboxylic acid, an aromatic diol, and an aromatic dicarboxylic acid;

The aromatic hydroxycarboxylic acid is of formula (6);
[Chemical 6]

The aromatic diol includes all of the chemical formula (7), the chemical formula (8), and the chemical formula (9);

[Chemistry 7]

[化8]

[Chemistry 9]

The aromatic dicarboxylic acid is of formula (10);
[化10]

And the formulation is as follows: 20 mol% ≦ chemical formula (6) composition ≦ 70 mol%;

15 mol % ≦ [chemical formula (7) composition + chemical formula (8) composition + chemical formula (9) composition] ≦ 40 mol%; wherein [chemical formula (7) composition + chemical formula (8) composition] (mole %) ≧ Chemical formula (9) composition (% by mole),

The composition of each component of the chemical formulas (7), (8) and (9) is >0 mol%;

15 mole % ≦ chemical formula (10) composition ≦ 40 mol%;

Further, for all the hydroxyl groups in (6), (7), (8), and (9), 1.05 to 1.15 moles of acetic anhydride is present and melt polymerization is carried out under reflux of acetic acid.

A fifth aspect of the present invention relates to a method for producing a wholly aromatic liquid crystal polyester according to a fourth aspect of the present invention, which further comprises a step of producing a wholly aromatic polyester by solid polycondensation, The wholly aromatic liquid crystal polyester has a melting point of 320 ° C or more.

Effect of invention

The resin composition composed of the wholly aromatic polyester of the present invention is a wholly aromatic obtained by obtaining a heat resistance corresponding to surface adhesion (SMT), and an injection molded body having a thin meat portion of 0.03 to 0.15 mm and good moldability. The resin composition composed of polyester is extremely useful as an injection molding material such as an electronic component.

The effect of the present invention depends on the characteristics of the liquid crystal polyester having the resin composition of the present invention remaining unchanged or slightly increased in the process from the temperature of 380 ° C in the molten state to the temperature before (melting point - 30 ° C), although The temperature of the mold cavity filling process is lowered, and the fluidity is maintained in a wide range of molding temperatures, and the resin filling of the thin meat portion of 0.03 mm to 0.15 mm and more preferably 0.03 mm to 0.1 mm can be achieved. In this application, it is sometimes referred to as "curing speed (or viscosity increasing) suppression effect".

Fig. 1 is a plan view and a side view showing the outline of the test piece.

Form for implementing the invention

The wholly aromatic polyester of the present invention is obtained by polycondensing an aromatic hydroxycarboxylic acid, an aromatic diol, and an aromatic dicarboxylic acid (including these derivatives, the same applies hereinafter) in a total amount of 100 mol%.

The constituent unit derived from the aromatic hydroxycarboxylic acid in the wholly aromatic polyester of the present invention is the chemical formula (1), which can be obtained by using, for example, p-hydroxybenzoic acid (chemical formula (6)).
[11]

[化12]

In the wholly aromatic polyester of the present invention, the constituent unit (chemical formula (1)) is set to 20 mol% to 70 mol% (including the threshold value, the same applies hereinafter). It is preferably from 30 mol% to 65 mol%, and more preferably from 40 mol% to 65 mol%. When it is less than this range, heat resistance may be insufficient, and when it exceeds the range, a high molding temperature is required, and injection molding stability is not good. In addition, the viscosity change is large with respect to the temperature drop, and the melt resin filling property of the thin portion of the molded product may be deteriorated.

The wholly aromatic polyester of the present invention has three constituent units derived from an aromatic diol, and is represented by the chemical formula (2), the chemical formula (3), and the chemical formula (4). These can be obtained by using, for example, hydroquinone (chemical formula (7)), p-dihydroxybiphenyl (chemical formula (8)) 2,7-dihydroxynaphthalene (chemical formula (9)).
[Chemistry 13]

[Chemistry 14]

[化15]


[Chemistry 16]



[化17]



[化18]



In the wholly aromatic polyester of the present invention, the constituent units represented by the chemical formulas (2), (3), and (4) are 15 mol% to 40 mol% in total, and more preferably 15 mol%. 25 moles %. When it is less than this range, the change in viscosity is large with respect to a decrease in temperature, and the filling property of the thin portion of the molded product may be deteriorated. When it exceeds the above range, its melting point may sometimes be less than the standard corresponding to the SMT heat resistance, that is, less than the melting point of 320 °C.

In the wholly aromatic polyester of the present invention, the total number of moles of the constituent units represented by the chemical formula (2) and the chemical formula (3) is not less than the number of moles of the constituent unit represented by the chemical formula (4). When it is less than the threshold, there is a decrease in heat resistance.

In the wholly aromatic polyester of the present invention, the constituent unit derived from the aromatic carboxylic acid is the chemical formula (5), and it can be obtained by using, for example, terephthalic acid having a carboxyl group in the para position (chemical formula (10)).

[Chemistry 19]



[Chemistry 20]




In the wholly aromatic polyester of the present invention, the constituent unit represented by the chemical formula (5) is from 15 mol% to 40 mol%, more preferably from 15 mol% to 25 mol%. When it is less than this range, the change in viscosity is large with respect to a decrease in temperature, and the filling property of the thin portion of the molded product may be deteriorated.

Further, the wholly aromatic polyester of the present invention preferably has a melting point of 320 ° C or more, which is in accordance with ISO 11357-3 and ASTM D3418. For the measurement method, for example, a differential scanning calorimeter (DSC) manufactured by SEICO Electronics Co., Ltd. can be used. At this time, the temperature was raised from room temperature to 390 ° C at a temperature increase rate of 20 ° C / min, and the polymer was completely melted, and then the temperature was lowered to 50 ° C at a temperature drop rate of 10 ° C / min, and further increased at a temperature increase rate of 20 ° C / min. The highest point of the endothermic peak obtained at 420 ° C was taken as the melting point.

In the above-mentioned respective constituent units, when the molecular structure is overlooked, the wholly aromatic polyester-based aromatic hydroxycarboxylic acid and the aromatic dicarboxylic acid of the present invention are assigned to have an aromatic ring group. A structure having a strong chain rigidity is produced, and only a unit of aromatic diol is used, and a carbon-carbon bond which is freely rotatable and a naphthalene ring which has a substituent at the 2-position and the 7-position of the relaxation are disposed.

The inventors of the present invention have found that by such differentiation, it is possible to efficiently and in a balanced manner to exhibit crystals or liquid crystal cells due to aromatic hydroxycarboxylic acid and aromatic dicarboxylic acid moieties. The heat resistance of the molded body and the high fluidity of the melt are brought about; and the degree of molecular motion of the aromatic diol is partially reduced to alleviate the viscosity change caused by the temperature drop.

The method for producing the wholly aromatic liquid crystal polyester of the present invention may be a conventional method for producing a liquid crystal polyester resin, which may be carried out by a production method only by melt polymerization or a two-stage polymerization by melt polymerization and solid phase polymerization. Production method.

Among these methods, from the viewpoint of efficiently obtaining the wholly aromatic polyester compound of the present invention, it is preferred to formulate p-hydroxybenzoic acid (chemical formula (6)) and hydroquinone (chemical formula (in the chemical formula ( 7)), biphenyl (chemical formula (8)), 2,7-dihydroxynaphthalene (chemical formula (9)), terephthalic acid (chemical formula (10)) total 100 mol%, for all of these compounds The hydroxyl group is present in a melt polymerization of 1.05 to 1.15 moles of acetic anhydride under reflux of acetic acid.

Further, when the molar equivalent of the acetic anhydride to be added greatly exceeds the above range, the reaction may not easily proceed.

When the solid phase polymerization is further carried out on the polymer obtained by melt polymerization, the prepolymer obtained by melt polymerization is pulverized after being solidified by cooling to form a powder or a sheet, and it is preferred to select a conventional one. The solid phase polymerization method is, for example, a method in which a prepolymer resin is heat-treated at a temperature of 200 to 350 ° C for 1 to 30 hours in an inert atmosphere such as nitrogen. The solid phase polymerization may be carried out while stirring, or may be carried out while standing still without stirring.

In the polymerization, with or without a catalyst. As the catalyst to be used, a conventional catalyst for polycondensation of polyester can be used. Examples thereof include metal salt catalysts such as magnesium acetate, first tin acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide, and organic compound catalysts such as N-methylimidazole.

The polymerization apparatus for melt polymerization is not particularly limited, and a reaction apparatus for a reaction of a general high viscosity fluid is preferably used. Examples of the reaction apparatus include, for example, a stirring type polymerization reaction apparatus, a kneading machine, a roll mill, a Banbury internal mixer, and the like, which are generally used for resin kneading, and the stirring type polymerization reaction apparatus is A stirring device having various anchoring wings of an anchor type, a multi-stage type, a spiral belt type, a spiral shaft type, or the like.

When the wholly aromatic polyester of the present invention is used as a material for injection molding, as a general example, 10 to 40 parts by weight of ground glass fiber, talc, mica, glass piece, and clay are melt-kneaded for 100 parts by weight of the wholly aromatic polyester. a resin composition such as sericite, calcium carbonate, calcium citrate, cerium oxide, aluminum oxide, aluminum hydroxide, calcium hydroxide, graphite, amorphous carbon, potassium titanate, carbon fiber, various whiskers, etc. After use. In addition to the aforementioned filler materials, other filler materials, colorants, dispersants, plasticizers, antioxidants, flame retardants, and the like may be added.

Further, in the present invention, a so-called aromatic polyfunctional monomer which is used in the synthesis of a liquid crystal polyester can be used without departing from the effects of the present invention. In particular, a part of p-hydroxybenzoic acid is replaced by 6-hydroxy-2-naphthoic acid, and the effect of maintaining fluidity as it is and lowering the molding processing temperature can be obtained.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited to the following examples.

The production example of the liquid crystal polyester (LCP) is shown below.

(Example 1 Production of Thermotropic Liquid Crystalline Polyester A)

SUS316 was used as the material, and in a polymerization tank with a 6-liter internal volume of a double-helical stirring wing, p-hydroxybenzoic acid (HBA, chemical formula (6)) 1325.97 g (9.60 mol), 4,4'-dihydroxybiphenyl was placed. (BP, chemical formula (7)) 178.76g (0.96 moles), hydroquinone (HQ, chemical formula (8)) 140.94g (1.28 moles), 2,7-dihydroxynaphthalene (2,7-DON, Chemical formula (9)) 153.76 g (0.96 mol), terephthalic acid (TPA, chemical formula (10)) 531.62 g (3.2 mol), potassium acetate 0.30 g as a catalyst, and magnesium acetate 0.30 g, 3 times The pressure-reduction of the polymerization tank-nitrogen injection was carried out for nitrogen replacement, and further, 1764.10 g (17.28 mol) of acetic anhydride was added, and the rotation speed of the stirring blade was set to 70 rpm, and the temperature was raised to 150 ° C over 1.5 hours, and it was carried out under reflux. Hourly oxime reaction.

After completion of the acetylation, the polymerization tank in the acetic acid distillation state was heated at 0.5 ° C /min. When the temperature of the reaction gas was 305 ° C, the polymer was taken out from the discharge port at the lower portion of the reactor, and solidified by cooling. The obtained polymer was pulverized into a size of a sieve having a pore size of 2.0 mm by a pulverizer to obtain a prepolymer.

Next, 950 g of the prepolymer obtained above was placed in a solid phase polymerization apparatus, and while flowing nitrogen, the heater temperature was raised from room temperature at room temperature, and the temperature was raised to 150 ° C over 1 hour, and then the temperature was raised to 250 after 6 hours. °C, kept at 250 ° C for 1 hour. Further, the temperature was raised to 270 ° C over 5 hours, and the temperature was raised to 290 ° C over 5 hours, and the temperature was raised to 305 ° C over 4 hours, and maintained at 305 ° C for 1 hour to carry out solid phase polymerization. Thus, about 880 g of a powdery thermotropic liquid crystal polyester (A) was obtained. The obtained thermotropic liquid crystal polyester (A) comprises: the constituent unit of the aromatic hydroxycarboxylic acid is the chemical formula (1), 60 mol%; the constituent unit of the aromatic diol is the chemical formula (2), 6 mol% Chemical formula (3), 8 mol%, and chemical formula (4), 6 mol% (the total number of moles of the chemical formula (2) to the chemical formula (4) is 20 mol%); and the aromatic dicarboxylic acid is derived from The constituent units are chemical formula (5), 20 mol%; melting point is 338 °C.

The fillers (1) to (3) described below were added to 100 parts by weight of the thermotropic liquid crystal polyester (A) obtained as described above to obtain a thermotropic liquid crystal polyester (A) composition.

Then, the tests (1) to (4) described later were carried out using the above composition. The results are shown in Table 1.
(Example 2 Production of Thermotropic Liquid Crystal Polyester B)
Put p-hydroxybenzoic acid (HBA, formula (6)) 1325.97g (9.60 mol), 4,4'-dihydroxybiphenyl (BP, chemical formula (7)) 268.14g (1.44 mol), p-phenylene Phenol (HQ, chemical formula (8)) 123.32g (1.12 mole), 2,7-dihydroxynaphthalene (2,7-DON, chemical formula (9)) 103.17g (0.64 mole), terephthalic acid (TPA Chemical formula (10): 531.62 g (3.2 mol), 0.30 g of potassium acetate as a catalyst, and 0.30 g of magnesium acetate, and a powdery thermotropic liquid crystal polyester (B) was obtained in the same manner as the thermotropic liquid crystal polyester A. The obtained thermotropic liquid crystal polyester (B) comprises: the constituent unit of the aromatic hydroxycarboxylic acid is the chemical formula (1), 60 mol%; the constituent unit of the aromatic diol is the chemical formula (2), 9 mol% Chemical formula (3), 7 mole %, and chemical formula (4), 4 mole % (the total number of moles of the chemical formula (2) to the chemical formula (4) is 20 mol%); and the aromatic dicarboxylic acid is derived from The constituent units are chemical formula (5), 20 mol%; melting point is 344 °C.

The fillers (1) to (3) described below were added to 100 parts by weight of the thermotropic liquid crystal polyester (B) obtained as described above to obtain a thermotropic liquid crystal polyester (B) composition.

Then, the tests (1) to (4) described later were carried out using the above composition. The results are shown in Table 1.

(Comparative Example 1 Production of Thermotropic Liquid Crystal Polyester C)

Put p-hydroxybenzoic acid (HBA, chemical formula (6)) 1325.95g (9.60 moles), 4,4'-dihydroxybiphenyl (BP, chemical formula (7)) 595.87g (3.20 moles), p-phenylene Formic acid (TPA, chemical formula (10)) 398.71g (2.40 mole), isophthalic acid (IPA) 132.90g (0.80 mole), potassium acetate 0.16g as catalyst and 0.48g magnesium acetate, 3 times polymerization After the pressure reduction of the tank-nitrogen injection for nitrogen substitution, 1715.11 g (16.80 mol) of acetic anhydride was further added, and in the same manner as in Example 1 (reactor temperature at the time of extraction was 310 ° C), a prepolymer was obtained, followed by solidification. The phase polymerization (end temperature was 320 ° C) gave a thermotropic liquid crystal polyester (C). The obtained thermotropic liquid crystal polyester comprises: the constituent unit of the aromatic hydroxycarboxylic acid is the chemical formula (1), 60 mol%; the constituent unit of the aromatic diol is the chemical formula (2), 20 mol%; and the aromatic The constituent unit of the group dicarboxylic acid is 20 mol% of the total of the chemical formula (5), 15 mol%, and IPA5 mol; the melting point is 355 °C.

The fillers (1) to (3) described below were added to 100 parts by weight of the thermotropic liquid crystal polyester (C) obtained as described above to obtain a thermotropic liquid crystal polyester (C) composition.

Then, the tests (1) to (4) described later were carried out using the above composition. The results are shown in Table 1.

The characteristics and addition amounts of various fillers used in the examples and comparative examples of the present invention are shown below.

(1) Talc: NIPPON TALC Co., Ltd., "MS-KY" (quantitative average particle size 23 μm), 14 parts by weight

(2) Glass fiber:

Nitto Boseki Co., Ltd., SS05DE-413SP (number average fiber length 100μm, number average fiber diameter 6μm), 29 parts by weight

(3) Carbon black (CB): manufactured by Cabot Co., Ltd., "REGAL99I", 1 weight

(experiment method)

(1) Determination of melt viscosity

The melt viscosity was a capillary rheometer (2010, manufactured by INTESCO Co., Ltd.), and a capillary having a diameter of 1.00 mm, a length of 40 mm, and an inflow angle of 90° was used, and the shear rate was 100 sec ^-1 , from 300 ° C to +4 ° C . / The temperature is increased at a constant rate of heating, and the apparent viscosity is measured. Further, in the same manner, the apparent viscosity was measured from 380 ° C at a constant speed of -4 ° C / minute, and the difference between the temperature at which the viscosity at the time of temperature rise began to rise was regarded as the supercooling temperature. Further, the test was carried out by using a resin composition which was previously dried in an air oven at 150 ° C for 4 hours.

(2) Determination of melting point

The melting point of the thermotropic liquid crystal polyester is determined by a differential scanning calorimeter (DSC) manufactured by SEICO Electronics Co., Ltd. At this time, the temperature was raised from room temperature to 390 ° C at a temperature increase rate of 20 ° C / min, and the polymer was completely melted, and then cooled to 50 ° C at a rate of 10 ° C / min, and further heated to 420 ° C at a rate of 20 ° C / min. The highest point of the endothermic peak obtained at this time was regarded as the melting point.

(3) Determination of thin meat flowability

(Test piece molding)

Agglomerates of the obtained resin composition were measured by an injection molding machine (LD10EH2 manufactured by Sodick) using a mold having a width of 2.0 mm, a length of 40 mm, and a thickness of 0.10 mm, and the cylinder temperature was set to an apparent melt viscosity (temperature rise). The value at which the value started to stabilize was evaluated by measuring the flow length at an injection temperature of 133 mm/sec and a mold temperature of 80 °C. The mold is on the gate side and has a cavity of 2.0 mm wide by 0.1 mm thick. The better the fluidity of the resin injected by a certain stroke, the more the injection amount of the cavity is increased, and the length of the thin molded portion of the molded product (=flow Long) increases. Fig. 1 is a plan view and a side view showing the test piece. Further, since the predetermined fluidity was confirmed by the mold having the cavity of 0.1 mm in thickness, it was naturally possible to obtain the above-mentioned thin meat fluidity in the mold of the cavity having a thickness of 0.15 mm.

Further, the flow length was measured for the length of the thinnest portion, and an average value of N = 20 was taken.

(4) Determination of shrinkage rate of molded articles

The pellet of the obtained resin composition was measured by the same method as in the measurement of the fluidity of the thin meat using an injection molding machine (IS-80 manufactured by Toshiba Corporation), and the mold having a gate at one end was used to have a width of 100 mm × A gusset having a length of 100 mm and a thickness of 1.0 mm was measured for the molding shrinkage ratio of the flow direction (MD) of the gusset and the direction (TD) at right angles to the flow direction. For the measurement, a measuring microscope (MF200 manufactured by Mitutoyo) was used.
[Table 1]

INDUSTRIAL APPLICABILITY The resin composition composed of the wholly aromatic polyester of the present invention has excellent surface heat resistance (SMT) heat resistance and thin moldability, and a thin meat portion having a thickness of 0.03 mm to 0.15 mm can be obtained, and the meat processing property is good. The injection molded body is suitable for use in camera module parts, optical pickup lens holders for CDs and DVDs.

Claims (5)

A wholly aromatic liquid crystal polyester obtained by polycondensing an aromatic hydroxycarboxylic acid, an aromatic diol, and an aromatic dicarboxylic acid (including the derivatives thereof) in a total amount of 100 mol%;
The constituent unit of the aromatic hydroxycarboxylic acid is composed of the chemical formula (1);
[Chemical 1]

The constituent unit of the aromatic diol is composed of the chemical formula (2), the chemical formula (3) and the chemical formula (4);
[Chemical 2]


[Chemical 3]


[Chemical 4]


The constituent unit of the aromatic dicarboxylic acid is composed of the chemical formula (5);
[Chemical 5]

And 20 mol % ≦ chemical formula (1) composition ≦ 70 mol%;
15 mol % ≦ [chemical formula (2) composition + chemical formula (3) composition + chemical formula (4) composition] ≦ 40 mol%;
Wherein [chemical formula (2) composition + chemical formula (3) composition] (mol%) ≧ chemical formula (4) composition (mol%);
Here, the composition of each repeating unit of the chemical formulas (2), (3), and (4) is >0 mol%;
15 mol % ≦ chemical formula (5) composition ≦ 40 mol %; and the above-mentioned wholly aromatic liquid crystal polyester has a melting point of 320 ° C or more.
An injection molded body obtained by injection molding a resin composition containing the wholly aromatic liquid crystal polyester of the first aspect of the patent application, and having a thickness of 0.03 to 0.15 mm.
An electronic component using an injection molded body as in the second aspect of the patent application.
A method for producing a wholly aromatic liquid crystal polyester, which comprises polycondensing a total of 100 mol% of an aromatic hydroxycarboxylic acid, an aromatic diol and an aromatic dicarboxylic acid;
The aromatic hydroxycarboxylic acid is of formula (6);
[Chemical 6]

The aromatic diol includes all of the chemical formula (7), the chemical formula (8), and the chemical formula (9);
[Chemistry 7]


[化8]



[Chemistry 9]

The aromatic dicarboxylic acid is of formula (10);
[化10]




And its deployment is as follows:
20 mol % ≦ chemical formula (6) composition ≦ 70 mol%;
15 mol % ≦ [chemical formula (7) composition + chemical formula (8) composition + chemical formula (9) composition] ≦ 40 mol%;
Wherein [chemical formula (7) composition + chemical formula (8) composition] (mol%) ≧ chemical formula (9) composition (mol%), chemical composition (7), (8) and (9) composition of components >0 Moer%;

15 mole % ≦ chemical formula (10) constitutes ≦40 mol%; and for all hydroxyl groups in (6), (7), (8), (9), 1.05 to 1.15 mol equivalent of acetic anhydride is present The melt polymerization was carried out under reflux of acetic acid.
The method for producing a wholly aromatic liquid crystal polyester according to claim 4, further comprising the step of producing a wholly aromatic polyester by solid polycondensation, wherein the wholly aromatic liquid crystal polyester has a melting point of 320 ° C or more .