JP2021024985A - Liquid crystal polyester resin - Google Patents

Abstract

To provide a liquid crystal polyester resin excellent in fluidity, heat resistance and mechanical strength.SOLUTION: There is provided a liquid crystal polyester obtained by polymerizing each of the following monomers (I) to (V): with the proviso that numerical values in parentheses represent a range of the composition ratio (mol%) of the repeating unit based on each monomer in the liquid crystal polyester. (I)4-hydroxy benzoic acid (51 to 69), (II)6-hydroxy-2-naphthoic acid (1 to 5.5), (III) hydroquinone (7 to 19), (IV) 4,4'-dihydroxybiphenyl (5 to 11), (V) terephthalic acid (12 to 24), and the composition ratio of (III) is equal to or greater than (IV).SELECTED DRAWING: None

Description

The present invention relates to a liquid crystal polyester resin having excellent heat resistance and mechanical strength.

Liquid crystal polyester resin is excellent in mechanical properties such as heat resistance and rigidity, chemical resistance, low water absorption, dimensional accuracy, etc., so its use is expanding not only for molded products but also for various applications such as fibers and films. It's getting better. Especially in the information and communication fields such as personal computers and smartphones, there is an increasing demand for high integration, miniaturization, thinning, and low profile of parts, and the excellent moldability of liquid crystal polyester resin is increasing. That is, by taking advantage of the characteristics that other polymers do not have, that is, good fluidity and no burrs, the amount used has been greatly expanded.

However, in recent years, the reflow temperature has become high in electronic component applications such as connectors due to the lead-free soldering, and even in molded products of liquid crystal polyester resin, swelling of the molded product surface called blister caused by the reflow treatment at high temperature has occurred. Is a problem.

It is considered that the generation of such blisters is caused by air existing in the mold or hopper, decomposition gas contained in the resin, air or moisture.

In addition, when the reflow temperature rises, there is a problem that the molded product of the liquid crystal polyester resin tends to warp, and in order to suppress the occurrence of warpage, a filler such as talc may be added to the liquid crystal polyester resin. Are known.

However, since talc contains a small amount of water, in the liquid crystal polyester resin composition containing talc, although the occurrence of warpage of the molded product is suppressed, there is a problem that the occurrence of blisters is more likely to increase. It has.

In order to solve such a problem of blister generation in a molded product of a liquid crystal polyester resin, an all-aromatic liquid crystal polyester resin composed of a specific structural unit has been proposed (Patent Document 1).

JP-A-2017-137438

However, the all-aromatic liquid crystal polyester described in Patent Document 1 does not have sufficient heat resistance and mechanical strength to meet the recent high demands for miniaturization, thinning, and complicated shape of parts, and is electrically charged. -In some cases, it was not suitable for applications such as electronic parts.

An object of the present invention is to provide a liquid crystal polyester resin having excellent fluidity, heat resistance and mechanical strength.

As a result of diligent studies in view of the above problems, the present inventors have excellent heat resistance and mechanical strength without impairing fluidity by polycondensing a monomer giving a specific repeating unit at a predetermined ratio. We have found that a liquid polyester resin can be obtained, and have completed the present invention.

［式中、
ｐ、ｑ、ｒ、ｓおよびｔは、それぞれ、液晶ポリエステル樹脂中での各繰返し単位の組成比（モル％）であり、以下の条件を満たす：
５１≦ｐ≦６９、
１≦ｑ≦５．５、
７≦ｒ≦１９、
５≦ｓ≦１１、
１２≦ｔ≦２４、
ｒ≧ｓ］
で表される繰返し単位から構成される液晶ポリエステル樹脂。
〔２〕ｐおよびｑは、１２＜ｐ／ｑ＜１９を満たす、〔１〕に記載の液晶ポリエステル樹脂。
〔３〕ｒおよびｓは、０．５≦ｒ／（ｒ＋ｓ）＜０．６を満たす、〔１〕または〔２〕に記載の液晶ポリエステル樹脂。
〔４〕結晶融解温度は３２０〜３６０℃である、〔１〕〜〔３〕のいずれかに記載の液晶ポリエステル樹脂。
〔５〕荷重たわみ温度は２２０℃以上である、〔１〕〜〔４〕のいずれかに記載の液晶ポリエステル樹脂。
〔６〕〔１〕〜〔５〕のいずれかに記載の液晶ポリエステル樹脂１００質量部に対し、繊維状、板状または粉末状の充填材０．１〜２００質量部を含む、液晶ポリエステル樹脂組成物。
〔７〕〔１〕〜〔５〕のいずれかに記載の液晶ポリエステル樹脂あるいは〔６〕に記載の液晶ポリエステル樹脂組成物から構成される成形品。 That is, the present invention includes the following preferred embodiments.
[1] Equations (I) to (V)

[During the ceremony,
p, q, r, s and t are composition ratios (mol%) of each repeating unit in the liquid crystal polyester resin, respectively, and satisfy the following conditions:
51 ≤ p ≤ 69,
1 ≦ q ≦ 5.5,
7 ≦ r ≦ 19,
5 ≦ s ≦ 11,
12 ≦ t ≦ 24,
r ≧ s]
A liquid crystal polyester resin composed of repeating units represented by.
[2] The liquid crystal polyester resin according to [1], wherein p and q satisfy 12 <p / q <19.
[3] The liquid crystal polyester resin according to [1] or [2], wherein r and s satisfy 0.5 ≦ r / (r + s) <0.6.
[4] The liquid crystal polyester resin according to any one of [1] to [3], wherein the crystal melting temperature is 320 to 360 ° C.
[5] The liquid crystal polyester resin according to any one of [1] to [4], wherein the deflection temperature under load is 220 ° C. or higher.
[6] A liquid crystal polyester resin composition containing 0.1 to 200 parts by mass of a fibrous, plate-like or powder-like filler with respect to 100 parts by mass of the liquid crystal polyester resin according to any one of [1] to [5]. Stuff.
[7] A molded product composed of the liquid crystal polyester resin according to any one of [1] to [5] or the liquid crystal polyester resin composition according to [6].

According to the present invention, it is possible to provide a liquid crystal polyester resin having excellent fluidity, heat resistance and mechanical strength.

The liquid crystal polyester resin of the present invention is a polyester resin that forms an anisotropic molten phase, which is called a thermotropic liquid crystal polyester resin by those skilled in the art.

The properties of the anisotropic molten phase can be confirmed by a conventional polarization inspection method using an orthogonal deflector. More specifically, the confirmation of the anisotropic molten phase can be carried out by observing the sample placed on the Leitz hot stage at a magnification of 40 times under a nitrogen atmosphere using a Leitz polarizing microscope. The liquid crystal polyester resin of the present invention is optically anisotropic, that is, it transmits light when inspected between orthogonal polarizers. If the sample is optically anisotropic, polarized light will be transmitted even in the stationary state.

［式中、ｐ、ｑ、ｒ、ｓおよびｔは、それぞれ、液晶ポリエステル樹脂中での各繰返し単位の組成比（モル％）であり、以下の条件を満たす：
５１≦ｐ≦６９、
１≦ｑ≦５．５、
７≦ｒ≦１９、
５≦ｓ≦１１、
１２≦ｔ≦２４、
ｒ≧ｓ］
で表される繰返し単位から構成される。 The liquid crystal polyester resin of the present invention has formulas (I) to (V).

[In the formula, p, q, r, s and t are composition ratios (mol%) of each repeating unit in the liquid crystal polyester resin, and satisfy the following conditions:
51 ≤ p ≤ 69,
1 ≦ q ≦ 5.5,
7 ≦ r ≦ 19,
5 ≦ s ≦ 11,
12 ≦ t ≦ 24,
r ≧ s]
It consists of repeating units represented by.

The composition ratio p of the repeating unit represented by the formula (I) is preferably 53 to 67 mol%, more preferably 55 to 65 mol%.

The composition ratio q of the repeating unit represented by the formula (II) is preferably 2 to 5.3 mol%, more preferably 3 to 5 mol%.

Here, p and q preferably satisfy 12 <p / q <19, and more preferably 13 <p / q <16.

The composition ratio r of the repeating unit represented by the formula (III) is preferably 7.5 to 17 mol%, more preferably 8 to 12 mol%.

The composition ratio s of the repeating unit represented by the formula (IV) is preferably 6 to 10.5 mol%, more preferably 7 to 10 mol%.

Here, r and s preferably satisfy 0.5 ≦ r / (r + s) <0.6.

The composition ratio t of the repeating unit represented by the formula (V) is preferably 13 to 23 mol%, more preferably 15 to 21 mol%.

It is preferable that p + q + r + s + t = 100.

Further, it is preferable that r + s = t.

Examples of the monomer giving the repeating unit represented by the formula (I) include 4-hydroxybenzoic acid and ester-forming derivatives such as an acylated product, an ester derivative, and an acid halide.

Examples of the monomer giving the repeating unit represented by the formula (II) include 6-hydroxy-2-naphthoic acid and ester-forming derivatives such as an acylated product, an ester derivative and an acid halide.

Examples of the monomer giving the repeating unit represented by the formula (III) include hydroquinone and its alkyl, alkoxy or halogen substituents, and ester-forming derivatives such as acylated products thereof.

Examples of the monomer giving the repeating unit represented by the formula (IV) include 4,4'-dihydroxybiphenyl, its alkyl, alkoxy or halogen substituents, and ester-forming derivatives such as acylated products thereof. Can be mentioned.

Examples of the monomer giving the repeating unit represented by the formula (V) include terephthalic acid and its alkyl, alkoxy or halogen substituents, and ester-forming derivatives such as these ester derivatives and acid halides. Be done.

As described above, the liquid crystal polyester resin of the present invention preferably has [p + q + r + s + t = 100] with respect to the liquid crystal polyester resin composed of the repeating units represented by the formulas (I) to (V). Other repeating units may be further contained as long as the purpose is not impaired.

Examples of the monomer giving another repeating unit include other aromatic hydroxycarboxylic acids, aromatic hydroxyamines, aromatic diamines, aromatic aminocarboxylic acids, aromatic hydroxydicarboxylic acids, aliphatic diols, and aliphatic dicarboxylic acids. Examples thereof include aromatic mercaptocarboxylic acid, aromatic dithiol, aromatic mercaptophenol and combinations thereof.

The monomer giving these other repeating units is preferably 10 mol% or less with respect to the total of the monomers giving the repeating units represented by the formulas (I) to (V).

The method for producing the liquid crystal polyester resin of the present invention is not particularly limited, and a known polycondensation method of polyester for forming an ester bond between the above-mentioned monomer components, for example, a melt acidlysis method, a slurry polymerization method, or the like can be used. ..

The molten acidlysis method first heats a monomer to form a molten solution of a reactant, and then continues the reaction to obtain a molten polymer. A vacuum may be applied to facilitate the removal of by-products (eg, acetic acid, water, etc.) in the final stage of condensation. This method is particularly preferably used in the present invention.

The slurry polymerization method is a method of reacting in the presence of a heat exchange fluid, and the solid product is obtained in a state of being suspended in a heat exchange medium.

In both the melt acidlysis method and the slurry polymerization method, the polymerizable monomer component used in producing the liquid crystal polyester resin is subjected to the reaction as a modified form in which a hydroxyl group is esterified, that is, a lower acyl ester. You can also. The lower acyl group preferably has 2 to 5 carbon atoms, and more preferably 2 or 3 carbon atoms. Particularly preferably, a method of using the acetic acid ester of the monomer component in the reaction can be mentioned.

As the lower acyl ester of the monomer, one that is separately acylated and synthesized in advance may be used, or an acylating agent such as acetic anhydride may be added to the monomer during the production of the liquid crystal polyester resin to produce the monomer in the reaction system. it can.

In either the melt acidlysis method or the slurry polymerization method, a catalyst may be used if necessary.

Specific examples of the catalyst include organic tin compounds such as dialkyltin oxide (for example, dibutyltin oxide) and diaryltin oxide; metal oxides such as titanium dioxide; antimony compounds such as antimony trioxide; organics such as alkoxytitanium silicate and titanium alkoxide. Titanium compounds; alkaline and alkaline earth metal salts of carboxylic acids (eg potassium acetate); Lewis acids (eg boron trifluoride), gaseous acid catalysts such as hydrogen halide (eg hydrogen chloride) and the like.

The ratio of the catalyst used is usually 1 to 1000 ppm, preferably 2 to 100 ppm, based on the total amount of the monomers.

The liquid crystal polyester resin of the present invention thus obtained has a crystal melting temperature measured by a differential scanning calorimeter (DSC) of preferably 320 to 360 ° C, more preferably 330 to 350 ° C, and even more preferably. It is 335 to 345 ° C.

The liquid crystal polyester resin of the present invention has a melt viscosity measured by the method described later, preferably 12 to 25 Pa · s, more preferably 13 to 23 Pa · s, and further preferably 14 to 22 Pa · s.

The liquid crystal polyester resin of the present invention has a deflection temperature under load measured by a method described later, preferably 220 ° C. or higher, more preferably 230 ° C. or higher, still more preferably 240 ° C. or higher, and usually 300 ° C. or lower.

The liquid crystal polyester resin of the present invention has a tensile strength of preferably 200 MPa or more, more preferably 205 MPa or more, still more preferably 210 MPa, usually 280 MPa or less, as measured by a method described later, for a molded product composed of the same. is there.

The liquid crystal polyester resin of the present invention has a bending strength of preferably 125 MPa or more, more preferably 130 MPa or more, still more preferably 135 MPa, usually 250 MPa or less, as measured by a method described later, for a molded product composed of the same. is there.

The liquid crystal polyester resin of the present invention has a flexural modulus of preferably 10 GPa or more, more preferably 10.5 GPa or more, still more preferably 11 GPa or more, which is usually measured by a method described later, for a molded product composed of the same. Is 15 GPa or less.

The liquid crystal polyester resin of the present invention has an Izod impact strength of preferably 500 J / m or more, more preferably 510 J / m or more, still more preferably 520 J / m or more, as measured by a method described later, for a molded product composed of the same. It is usually 1000 J / m or less.

The present invention further provides a liquid crystal polyester resin composition obtained by blending one or more of fibrous, plate-like or powder-like fillers with the liquid crystal polyester resin of the present invention. The filler may be appropriately selected from substances known to be used in the resin composition, depending on the purpose of use, application, etc. of the liquid crystal polyester resin composition.

Examples of the fibrous filler include glass fiber, silica-alumina fiber, alumina fiber, carbon fiber, aramid fiber and the like. Among these, glass fiber is preferable because it has an excellent balance between physical properties and cost.

Examples of the plate-like or powder-like filler include talc, mica, graphite, wollastonite, calcium carbonate, dolomite, clay, glass flakes, glass beads, barium sulfate, titanium oxide and the like. Among these, talc is preferable because it has an excellent balance between physical properties and cost.

In the liquid crystal polyester resin composition of the present invention, the total amount of the filler is preferably 0.1 to 200 parts by mass, particularly preferably 10 to 100 parts by mass with respect to 100 parts by mass of the liquid crystal polyester resin. .. When the blending amount of the filler exceeds 200 parts by mass, the molding processability of the resin composition tends to decrease, and the cylinder and the mold of the molding machine tend to be worn out.

The liquid crystal polyester resin composition of the present invention further comprises a mold release agent such as a higher fatty acid, a higher fatty acid ester, a higher fatty acid amide, a higher fatty acid metal salt, a polysiloxane, and a fluororesin, as long as the effects of the present invention are not impaired. Additives known to be used in resin compositions, such as colorants such as pigments; antioxidants; heat stabilizers; UV absorbers; antistatic agents; surfactants, are used for the purposes of resin compositions and Depending on the application, one type or a combination of two or more types may be added.

Those having an external lubricant effect, such as higher fatty acids, higher fatty acid esters, higher fatty acid metal salts, and fluorocarbon-based surfactants, may be used by being attached to pellets in advance during molding.

In the liquid crystal polyester resin composition of the present invention, all components such as fillers and additives are added to the polyester resin, and crystal melting of the liquid crystal polyester resin is performed using a Banbury mixer, a kneader, a uniaxial or biaxial extruder, or the like. It can be prepared by melt-kneading at a temperature of crystal melting temperature + 50 ° C. from near the temperature.

The liquid crystal polyester resin and the liquid crystal polyester resin composition of the present invention thus obtained can be an injection molded product, a film, a sheet, a non-woven fabric, or the like by a molding method such as injection molding, compression molding, extrusion molding, or blow, which are conventionally known. Can be processed into molded products.

Since the liquid crystal polyester resin and the liquid crystal polyester resin composition of the present invention are excellent in fluidity, heat resistance and mechanical strength, electrical / electronic parts such as antennas, connectors and substrates, mechanical mechanical parts such as camera modules, automobile parts and the like It is preferably used as.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

The crystal melting temperature, melt viscosity, deflection temperature under load, tensile strength, bending strength, flexural modulus and Izod impact strength in the examples were measured by the methods described below.

<Crystal melting temperature>
After measuring the endothermic peak temperature (Tm1) observed when the sample is measured at a temperature rise condition of 20 ° C./min from room temperature using a differential scanning calorimeter (Exstar6000 manufactured by Seiko Instruments Co., Ltd.), from Tm1. It was held at a high temperature of 20 to 50 ° C. for 10 minutes. Next, the sample was cooled to room temperature under the temperature lowering condition of 20 ° C./min, and the endothermic peak when measured again under the temperature rising condition of 20 ° C./min was observed, and the temperature indicating the peak top was the crystal melting temperature (Tm). ).

<Melting viscosity>
The melt viscosity at 350 ° C. was measured by a melt viscosity measuring device (Capillary Graph 1D manufactured by Toyo Seiki Co., Ltd.) using a 0.7 mmφ × 10 mm capillary ^{under the condition of a shear rate of 1000 sec -1.}

<Deflection temperature under load>
Using an injection molding machine (UH1000-110 manufactured by Nissei Jushi Kogyo Co., Ltd.), injection molding was performed at a crystal melting temperature of + 10 to 30 ° C. and a mold temperature of 70 ° C., length 127 mm, width 12.7 mm, thickness. A 3.2 mm strip-shaped test piece was formed, and the temperature at which a predetermined deflection amount (2.54 mm) was measured at a load of 1.82 MPa and a heating rate of 2 ° C./min was measured using the strip-shaped test piece in accordance with ASTM D648.

<Tensile strength>
Using an injection molding machine with a mold clamping pressure of 15 tons (MINIMATM26 / 15 manufactured by Sumitomo Heavy Industries, Ltd.), injection molding is performed at a cylinder temperature of + 10 to 30 ° C and a mold temperature of 80 ° C, and a dumbbell-shaped tensile test piece. Was produced. The measurement was performed using INSTRON5567 (universal testing machine manufactured by Instron Japan Company Limited) at a distance between spans of 25.4 mm and a tensile speed of 5 mm / min.

<Bending strength, flexural modulus>
Using an injection molding machine with a mold clamping pressure of 15 tons (MINIMAT M26 / 15 manufactured by Sumitomo Heavy Industries, Ltd.), injection molding is performed at a cylinder temperature of + 10 to 30 ° C and a mold temperature of 80 ° C, and a strip-shaped bending test is performed. A piece (length 65 mm × width 12.7 mm × thickness 2.0 mm) was prepared. The bending test was performed by using INSTRON5567 (a universal testing machine manufactured by Instron Japan Company Limited) at a distance between spans of 40.0 mm and a compression speed of 1.3 mm / min.

<Izod impact strength>
The measurement was performed in accordance with ASTM D256 using the same test piece as the test piece used for the bending strength measurement.

In the examples, the abbreviations below refer to the following compounds.
POB: 4-Hydroxybenzoic acid BON6: 6-hydroxy-2-naphthoic acid HQ: Hydroquinone BP: 4,4'-dihydroxybiphenyl TPA: Terephthalic acid

Example 1
In a reaction vessel equipped with a stirrer with a torque meter and a distillate, POB, BON6, HQ, BP and TPA were charged so as to have a total amount of 6.5 mol at the composition ratio shown in Table 1, and the hydroxyl groups of all the monomers were further charged. 1.03 times the amount of acetic anhydride was charged with respect to the amount (molar), and deacetic acid polymerization was carried out under the following conditions.

The temperature was raised from room temperature to 145 ° C. in a nitrogen gas atmosphere in 1 hour, and the temperature was maintained at the same temperature for 30 minutes. Then, the temperature was raised to 350 ° C. over 5.5 hours while distilling off the acetic acid produced as a by-product, and then the pressure was reduced to 5 mmHg over 80 minutes. When a predetermined torque was exhibited, the polymerization reaction was terminated, the contents of the reaction vessel were taken out, and pellets of liquid crystal polyester resin were obtained by a pulverizer. The amount of distillate acetic acid at the time of polymerization was almost the same as the theoretical value.

The crystal melting temperature measured by the differential scanning calorimeter of the obtained liquid crystal polyester resin was 343 ° C. Table 2 shows the measurement results of the melt viscosity, deflection temperature under load, tensile strength, bending strength, flexural modulus and Izod impact strength of this liquid crystal polyester resin.

Examples 2-3 and Comparative Examples 1-2
A liquid crystal polyester resin was obtained in the same manner as in Example 1 except that the composition ratio of the monomers charged in the reaction vessel was changed as shown in Table 1. Table 2 shows the evaluation results of the crystal melting temperature, melt viscosity, deflection temperature under load, tensile strength, bending strength, flexural modulus and Izod impact strength of the obtained liquid crystal polyester resin.

The liquid crystal polyester resins of Examples 1 to 3 had a crystal melting temperature of 338 to 343 ° C. and a melt viscosity of 15.4 to 20.8 Pa · s, and were excellent in fluidity. Further, the deflection temperature under load is 245 to 250 ° C., which is excellent in heat resistance, and further, the tensile strength is 218 to 225 MPa, the bending strength is 142 to 144 MPa, and the flexural modulus is 12 to 13 GPa, which is excellent in mechanical strength. It was.

On the other hand, the liquid crystal polyester resins of Comparative Examples 1 and 2 showed excellent fluidity, but were inferior in heat resistance and mechanical strength.

Claims (7)

Equations (I)-(V)

[During the ceremony
p, q, r, s and t are composition ratios (mol%) of each repeating unit in the liquid crystal polyester resin, respectively, and satisfy the following conditions:
51 ≤ p ≤ 69,
1 ≦ q ≦ 5.5,
7 ≦ r ≦ 19,
5 ≦ s ≦ 11,
12 ≦ t ≦ 24,
r ≧ s]
A liquid crystal polyester resin composed of repeating units represented by. The liquid crystal polyester resin according to claim 1, wherein p and q satisfy 12 <p / q <19. The liquid crystal polypolyester resin according to claim 1 or 2, wherein r and s satisfy 0.5 ≦ r / (r + s) <0.6. The liquid crystal polyester resin according to any one of claims 1 to 3, wherein the crystal melting temperature is 320 to 360 ° C. The liquid crystal polyester resin according to any one of claims 1 to 4, wherein the deflection temperature under load is 220 ° C. or higher. A liquid crystal polyester resin composition containing 0.1 to 200 parts by mass of a fibrous, plate-like or powder-like filler with respect to 100 parts by mass of the liquid crystal polyester resin according to any one of claims 1 to 5. A molded product composed of the liquid crystal polyester resin according to any one of claims 1 to 5 or the liquid crystal polyester resin composition according to claim 6.