KR20210018034A - Liquid crystal polyester resin - Google Patents

Abstract

The present invention relates to a liquid crystal polyester resin having excellent flowability, heat resistance and mechanical strength. The present invention provided a liquid crystal polyester resin including repeating units represented by chemical formulae (I) to (V), wherein each of p, q, r, s and t represents the compositional ratio (mol%) of each repeating unit in the liquid crystal polyester resin and satisfies the following condition: 51 <= p <= 69, 1 <= q <= 5.5, 7 <= r <= 19, 5 <= s <= 11, 12 <= t <= 24, and r >= s.

Description

Liquid crystal polyester resin {LIQUID CRYSTAL POLYESTER RESIN}

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

Since the liquid crystal polyester resin is excellent in mechanical properties such as heat resistance and rigidity, chemical resistance, low water absorption, dimensional accuracy, etc., its use is expanding not only for molded products but also for various applications such as fibers and films. In particular, in the fields of information and communication such as personal computers and smart phones, higher integration, miniaturization, thinner, and low profile of parts are required, and excellent moldability of liquid crystal polyester resins, that is, , It has good fluidity and does not produce burrs.

However, in recent years, due to lead-free soldering, the reflow temperature is increasing in the use of electronic components such as connectors, and even in molded products of liquid crystal polyester resins, it is called a blister caused by reflow treatment at high temperatures. The occurrence of swelling on the surface of the molded article is a problem.

The generation of such blisters is considered to be caused by air existing in the mold or hopper, decomposition gas contained in the resin, and air or moisture.

In addition, when the reflow temperature becomes high, there is a problem that warpage is liable to occur in a molded article of a liquid crystal polyester resin, and it is known to blend a filler such as talc in the liquid crystal polyester resin in order to suppress the occurrence of warpage.

However, since talc contains a trace amount of moisture, in the liquid crystal polyester resin composition containing talc, the occurrence of warpage of the molded article is suppressed, but the occurrence of blisters is more likely to increase.

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

Japanese Patent Application Publication No. 2017-137438

However, the wholly aromatic liquid crystal polyester described in Patent Literature 1 is not sufficient in heat resistance and mechanical strength in response to the recent high demand for miniaturization, thickness reduction, and further complicated shape of parts, and is therefore suitable for applications such as electric and electronic parts. There were cases where it was not suitable.

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

The inventors of the present invention found out that by condensation polymerization of a monomer giving a specific repeating unit in a predetermined ratio in consideration of the above problems, a liquid crystal polyester resin having excellent heat resistance and mechanical strength can be obtained without impairing fluidity. , Came to complete the present invention.

That is, the present invention includes the following preferred embodiments.

(1) Formula (I)-(V)

[Formula 1]

[In the formula,

p, q, r, s and t are, respectively, the composition ratio (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]

Liquid crystal polyester resin composed of a repeating unit 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 load bending temperature is 220°C or higher.

[6] A liquid crystal polyester resin composition containing 0.1 to 200 parts by mass of a fibrous, plate or powdery filler with respect to 100 parts by mass of the liquid crystal polyester resin according to any one of [1] to [5].

[7] A molded article 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 excellent in 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 to those skilled in the art.

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

The liquid crystal polyester resin of the present invention is formula (I) to (V)

[Formula 2]

[In the formula, p, q, r, s, and t are each a composition ratio (mol%) of each repeating unit in a liquid crystal polyester resin, and the following conditions are satisfied:

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 formula (I) is preferably 53 to 67 mol%, and more preferably 55 to 65 mol%.

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

Here, it is preferable that p and q satisfy 12<p/q<19, and it is more preferable to satisfy 13<p/q<16.

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

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

Here, it is preferable that r and s satisfy 0.5≦r/(r+s)<0.6.

As for the composition ratio t of the repeating unit represented by Formula (V), 13-23 mol% is preferable, and 15-21 mol% is more preferable.

Moreover, it is preferable that it is p+q+r+s+t=100.

Moreover, it is preferable that it is 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 this 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 this acylated product, an ester derivative, and an acid halide. .

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

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

Examples of the monomer giving the repeating unit represented by formula (V) include terephthalic acid and this alkyl, alkoxy or halogen substituent, and ester derivatives such as ester derivatives and acid halides thereof.

As described above, the liquid crystal polyester resin of the present invention is [p + q + r + s + t = 100) with respect to the liquid crystal polyester resin constituted by repeating units represented by formulas (I) to (V). ] Is preferable, but other repeating units may be further contained within the range not impairing the object of the present invention.

As a monomer giving another repeating unit, other aromatic hydroxycarboxylic acid, aromatic hydroxyamine, aromatic diamine, aromatic aminocarboxylic acid, aromatic hydroxydicarboxylic acid, aliphatic diol, aliphatic dicarboxylic acid, 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 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 that forms an ester bond between the monomer components, for example, a melt acidolysis method, a slurry polymerization method, etc. can be used. have.

The melt acidolysis method is to heat a monomer for the first time to form a molten solution of a reaction substance, and then continue the reaction to obtain a molten polymer. Further, a vacuum may be applied to facilitate removal of volatile substances (eg, acetic acid, water, etc.) produced by the condensation in the final step. 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 a solid product is obtained while suspended in a heat exchange medium.

In either case of the melt acidolysis method and the slurry polymerization method, the polymerizable monomer component used when producing the liquid crystal polyester resin is a modified form in which a hydroxyl group is esterified, that is, a lower acyl ester to be provided to the reaction. May be. The lower acyl group preferably has 2 to 5 carbon atoms, more preferably 2 or 3 carbon atoms. Particularly preferred is a method of using the acetic acid ester of the monomer component for the reaction.

The lower acyl ester of the monomer may be separately acylated and synthesized in advance, or may be produced in the reaction system by adding an acylating agent such as acetic anhydride to the monomer at the time of production of the liquid crystal polyester resin.

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

As a specific example of a catalyst, organotin compounds, such as a dialkyl tin oxide (for example, dibutyl tin oxide) and a diaryl tin oxide; Metal oxides such as titanium dioxide; Antimony compounds such as antimony trioxide; Organic titanium compounds such as alkoxy titanium silicate and titanium alkoxide; Alkali and alkaline earth metal salts of carboxylic acids (for example, potassium acetate); Gaseous acid catalysts such as Lewis acid (for example, boron trifluoride) and hydrogen halide (for example, hydrogen chloride).

The rate of use of the catalyst is usually 1 to 1000 ppm, preferably 2 to 100 ppm with respect to the total amount of the monomer.

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 still 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 even more preferably 14 to 22 Pa·s. to be.

The liquid crystal polyester resin of the present invention has a load bending temperature measured by the method described below, 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, even more preferably 210 MPa or more, for a molded article composed of this, as measured by the method described later. , Usually 280 MPa or less.

The liquid crystal polyester resin of the present invention has a bending strength measured by the method described later with respect to a molded article composed of this, preferably 125 MPa or more, more preferably 130 MPa or more, further preferably 135 MPa or more. , Usually 250 MPa or less.

The liquid crystal polyester resin of the present invention has a bending elastic modulus measured by the method described later for a molded article composed of this, preferably 10 GPa or more, more preferably 10.5 GPa or more, and even more preferably 11 GPa or more. , Usually 15 GPa or less.

The liquid crystal polyester resin of the present invention has an Izod impact strength measured by the method described later with respect to a molded article made of it, preferably 500 J/m or more, more preferably 510 J/m or more, and even more preferably Is 520 J/m or more, and usually 1000 J/m or less.

The present invention further provides a liquid crystal polyester resin composition obtained by blending one or two or more of fibrous, plate, or powdery fillers with the liquid crystal polyester resin of the present invention. As the filler, from a substance known to be used in a resin composition, it may be appropriately selected according to the purpose of use, the use, etc. of the liquid crystal polyester resin composition.

Examples of the fibrous filler include glass fiber, silica alumina fiber, alumina fiber, carbon fiber, and aramid fiber. Among these, glass fibers are preferable from the viewpoint of excellent balance between physical properties and cost.

Examples of the plate-like or powdery filler include talc, mica, graphite, wollastonite, calcium carbonate, dolomite, clay, glass flakes, glass beads, barium sulfate, and titanium oxide. Among these, talc is preferable from the viewpoint of 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, based on 100 parts by mass of the liquid crystal polyester resin. When the blending amount of the filler exceeds 200 parts by mass, there is a tendency that the molding processability of the resin composition decreases, or the wear of the cylinder or the mold of the molding machine increases.

The liquid crystal polyester resin composition of the present invention further includes 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 within a range that does not impair the effect of the present invention; Coloring agents such as dyes and pigments; Antioxidant; Heat stabilizer; Ultraviolet absorber; Antistatic agent; Additives known to be used in the resin composition, such as surfactants, may be added singly or in combination of two or more depending on the purpose and use of the resin composition.

For those having an external lubricating effect such as higher fatty acids, higher fatty acid esters, higher fatty acid metal salts, and fluorocarbon surfactants, they may be used by adhering to the 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 a Banbury mixer, a kneader, a single screw or twin screw extruder, etc. are used to close the crystal melting temperature of the liquid crystal polyester resin. From this, it can be prepared by melt-kneading at a temperature of +50°C.

The liquid crystal polyester resin and liquid crystal polyester resin composition of the present invention thus obtained are molded products such as injection molded products, films, sheets, and nonwoven fabrics by molding methods such as injection molding, compression molding, extrusion molding, and blow. Can be processed.

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

Hereinafter, the present invention will be described in detail by examples, but the present invention is not limited thereto.

Example

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

<Crystal melting temperature>

After measuring the endothermic peak temperature (Tm1) observed when the sample was measured under a temperature rising condition of 20°C/min from room temperature using a differential scanning calorimeter (Exstar6000 manufactured by Seiko Instruments Co., Ltd.), 20 to 50°C than Tm1 It was held for 10 minutes at high temperature. Subsequently, the sample was cooled to room temperature under a temperature-falling condition of 20°C/min, and the endothermic peak was further measured under a temperature-raising condition of 20°C/min. The temperature indicating the peak top was determined. Melting temperature (Tm ).

<Melt viscosity>

Using a melt viscosity measuring apparatus (Capillarograph 1D manufactured by Toyo Seiki Co., Ltd.), the melt viscosity at 350°C was measured under conditions of a shear rate of 1000 sec ^-1 using a capillary of 0.7 mmφ × 10 mm Measured.

<Load bending temperature>

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

<The tensile strength>

Using an injection molding machine with a mold clamping pressure of 15 t (minimat M26/15 manufactured by Sumitomo Heavy Industries Co., Ltd.), injection molding was 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. Using INSTRON5567 (a universal testing machine manufactured by Instron Japan Company Limited), it was measured 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 clamping pressure of 15 t (minimat M26/15 manufactured by Sumitomo Heavy Machinery Co., Ltd.), injection molding was performed at a cylinder temperature of +10 to 30°C and a mold temperature of 80°C using a single-decker bending test piece (65 mm in length × 12.7 mm in width × 2.0 mm in thickness) was produced. In the bending test, the three-point bending test was performed at a distance between spans of 40.0 mm and a compression speed of 1.3 mm/min using INSTRON5567 (a universal testing machine manufactured by Instron Japan Company Limited).

<Izod impact strength>

It measured according to ASTM D256 using the same test piece as the test piece used for the bending strength measurement.

In the Examples, the following symbols represent the following compounds.

POB: 4-hydroxybenzoic acid

BON6: 6-hydroxy-2-naphthoic acid

HQ: Hydroquinone

BP: 4,4'-dihydroxybiphenyl

TPA: terephthalic acid

Example 1

POB, BON6, HQ, BP, and TPA were injected into a reaction vessel equipped with a stirring device equipped with a torque meter and an outlet pipe in the composition ratio shown in Table 1 so that the total amount was 6.5 mol, and further 1.03 times mole of acetic anhydride was added to the amount of hydroxyl groups (molar) of the monomer, and deacetic acid polymerization was carried out under the following conditions.

The temperature was raised from room temperature to 145°C for 1 hour in a nitrogen gas atmosphere, and maintained at the same temperature for 30 minutes. Subsequently, the temperature was raised to 350° C. over 5.5 hours while distilling off the by-product acetic acid, and then the pressure was reduced to 5 mmHg over 80 minutes. When the predetermined torque was displayed, the polymerization reaction was terminated, the contents of the reaction vessel were taken out, and pellets of a liquid crystal polyester resin were obtained by a crusher. The amount of acetic acid flowing out during 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, load bending temperature, tensile strength, flexural strength, flexural modulus, and Izod impact strength of this liquid crystal polyester resin.

Examples 2 to 3 and Comparative Examples 1 to 2

A liquid crystal polyester resin was obtained in the same manner as in Example 1, except that the composition ratio of the monomer injected into the reaction vessel was changed as shown in Table 1. Table 2 shows the evaluation results of the crystal melting temperature, melt viscosity, load bending temperature, tensile strength, flexural strength, flexural modulus, and Izod impact strength of the obtained liquid crystal polyester resin.

The liquid crystal polyester resin of Examples 1-3 was excellent in fluidity with a crystal melting temperature of 338 to 343°C and a melt viscosity of 15.4 to 20.8 Pa·s. Moreover, the load bending temperature was 245 to 250°C, which was excellent in heat resistance, and the tensile strength was 218 to 225 MPa, the bending strength was 142 to 144 MPa, and the flexural modulus was 12 to 13 GPa, and the mechanical strength was excellent.

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

Claims (7)

Formula (I)-(V)

[In the formula,
p, q, r, s, and t are the 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]
Liquid crystal polyester resin composed of a repeating unit represented by. The method of claim 1,
p and q satisfy 12<p/q<19, a liquid crystal polyester resin. The method according to claim 1 or 2,
r and s satisfy 0.5≦r/(r+s)<0.6, a liquid crystal polyester resin. The method according to any one of claims 1 to 3,
The crystal melting temperature is 320 to 360°C, a liquid crystal polyester resin. The method according to any one of claims 1 to 4,
The load bending temperature is 220 degreeC or more, the liquid crystal polyester resin. A liquid crystal polyester resin composition containing 0.1 to 200 parts by mass of a fibrous, plate or powdery 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 article 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.