TWI591120B - Wholly aromatic liquid crystalline polyester resin composition with excellent blister resistance - Google Patents

Description

Fully aromatic liquid crystalline polyester resin composition with excellent bubble resistance

The present invention claims the priority of the Korean Patent Application No. 2011-0112179, the entire disclosure of which is incorporated herein by reference.

The present invention relates to a wholly aromatic liquid crystalline polyester resin composition having improved bubble resistance; more particularly, to a wholly aromatic liquid crystalline polyester resin composition which has increased bubble resistance but does not impair its Heat resistance and mechanical properties.

The all-aromatic liquid crystalline polyester resin has excellent thermal conductivity and dimensional stability, as well as excellent melt fluidity, and thus has been widely used as a material for precise injection in electronic component applications.

In particular, the wholly aromatic liquid crystalline polyester is reinforced with various fillers, has high heat resistance and excellent dimensional stability, electrical insulation and mechanical properties, and thus has been used as a connector, a memory card socket and other needs. Materials for parts of high heat resistant electronic devices are increasingly being used as alternatives to other polymeric materials.

The wholly aromatic liquid crystalline polyester resin is a thermoplastic polymer obtained by a polycondensation reaction, and a resin compound can be obtained by kneading a polyester resin with an inorganic filler such as glass fiber or talc, and the resulting mixture is extruded. Such a resin compound can be further processed, for example, by injection processing to form a product.

Since electronic parts tend to be thin and light, the demand for wholly aromatic polyester resin compounds having improved high heat resistance and bubble resistance is increasing.

In addition, the application of the resin compound to a connector or a memory card socket in an electronic device requires complicated performance, and therefore, as an electronic component, a wholly aromatic liquid crystalline polyester resin compound is required. Improved heat resistance and ability to maintain other properties.

However, among these wholly aromatic liquid crystalline polyester resin compounds, the resin compound is only filled with glass fiber and has high heat resistance, but has a bubble problem because heat treatment is performed near the melting point or high temperature processing (such as welding). At the time, water or a volatile substance in the resin compound swells and erupts from the surface, and the bubble problem causes a poor appearance of the molded body or a decrease in mechanical properties, and therefore, it is necessary to avoid the material applied to the electronic component.

Accordingly, the present invention is directed to a wholly aromatic liquid crystalline polyester resin composition which has improved bubble resistance without deteriorating heat resistance and mechanical properties, and can be used for materials of connectors or memory card socket parts.

One aspect of the present invention provides a wholly aromatic liquid crystalline polyester resin composition having improved bubble resistance, comprising a wholly aromatic liquid crystalline polyester resin having a melting point of between 300 and 450 ° C, A filler for enhancing physical properties and an inorganic filler powder.

Specifically, the filler for enhancing physical properties may comprise at least one selected from the group consisting of glass fibers and carbon fibers.

Moreover, the inorganic filler powder comprises at least one selected from the group consisting of calcium carbonate, quartz, tridymite, attapulgite, sillimanite, heavy vermiculite, talc, mica and carbon black.

The filler for enhancing physical properties contains the content of 5 to 90 parts by weight based on 100 parts by weight of the wholly aromatic liquid crystalline polyester resin.

The inorganic filler powder is contained in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the wholly aromatic liquid crystalline polyester resin.

The wholly aromatic liquid crystalline polyester resin combination according to the present invention will be further described hereinafter. Things.

In one embodiment of the present invention, the wholly aromatic liquid crystalline polyester resin composition comprises a wholly aromatic liquid crystalline polyester resin having a melting point of between 300 and 450 ° C, a filler for enhancing physical properties, and An inorganic filler powder.

According to the present embodiment, the first component constituting the wholly aromatic liquid crystalline polyester resin composition is a wholly aromatic liquid crystalline polyester resin, preferably selected from those having a melting point of between 300 and 450 ° C. Achieve high heat resistance and mechanical properties.

Due to its high melting point, the wholly aromatic liquid crystalline polyester resin has high heat resistance, and the wholly aromatic liquid crystalline polyester resin can be prepared by two operations as described below: (a) synthesizing a prepolymer of a wholly aromatic liquid crystalline polyester by polycondensation of at least two monomers; (b) synthesizing a wholly aromatic liquid crystalline polyester resin by solid state polycondensation of the prepolymer.

The monomer used in the operation (a) comprises at least one compound selected from the group consisting of aromatic diols, aromatic diamines, aromatic hydroxylamines, and aromatic dicarboxylic acids. The group consisting of (aromatic dicarboxylic acid); in addition, the monomer may further comprise an aromatic hydroxycarboxylic acid and/or an aromatic aminocarboxylic acid.

A solution condensation polymerization method or a bulk condensation polymerization method (bulk condensation polymerization) can be used in the synthesis method of the operation (a). Further, a monomer having enhanced reactivity such as a deuterated monomer which is pretreated by a chemical substance such as a deuterating agent such as an oxime agent to accelerate the condensation reaction of (a) can be used.

In operation (b) of the solid polycondensation reaction, appropriate thermal energy should be provided. The heat supply method includes a method of using a hot plate, a method of using hot air, and a method of using a high temperature fluid; By-products produced by solid-state polycondensation reactions can be purged with inert gas or vacuum purged.

The wholly aromatic liquid crystalline polyester resin can be prepared in the manner suggested above, but the invention is not limited to this method, and those having a melting point between 300 and 450 ° C can be selected.

Each of the wholly aromatic liquid crystalline polyester resins may contain various repeating units in its chain structure, such as the repeating unit shown below:

(1) Repeating units derived from aromatic diols:

-O-Ar-O-;

(2) Repeating units derived from aromatic diamines:

-HN-Ar-NH-;

(3) Repeating units derived from aromatic hydroxylamines:

-HN-Ar-O-;

(4) Repeating units derived from aromatic dicarboxylic acids:

-OC-Ar-CO-;

(5) Repeating units derived from aromatic hydroxycarboxylic acids:

-O-Ar-CO-;

(6) a repeating unit derived from an aromatic aminocarboxylic acid

-HN-Ar-CO-.

In these repeating units, Ar may be an aromatic compound in which phenylene, biphenylene, naphthalene or two phenyl groups are bonded to an element other than carbon or carbon, or It is an aromatic compound in which a phenyl group, a diphenylene group, a naphthalene group or two phenylene groups are bonded to an element other than carbon or carbon, wherein at least one hydrogen atom in the aromatic compound is substituted by another element.

The wholly aromatic liquid crystalline polyester resin composition according to this embodiment contains a filler to impart mechanical properties. The filler for enhancing physical properties preferably comprises at least one selected from the group consisting of glass fibers and carbon fibers, but the invention is not limited to such fillers.

The content of the filler for enhancing physical properties is contained in an amount of 5 to 90 parts by weight based on 100 parts by weight of the wholly aromatic liquid crystalline polyester resin. When the content of the filler is less than 5 parts by weight based on 100 parts by weight of the total aromatic liquid crystalline polyester resin, the wholly aromatic liquid crystalline polyester resin composition may have difficulty in achieving sufficient mechanical strength; When the content of the filler is more than 90 parts by weight based on 100 parts by weight of the wholly aromatic liquid crystalline polyester resin, the moldability of the wholly aromatic liquid crystalline polyester resin composition is lowered.

At the same time, the resin compound is formed only of a wholly aromatic liquid crystalline polyester resin and a filler for enhancing physical properties, which causes a bubble problem at a high temperature, and therefore, a small amount of inorganic filler powder is used to prevent this problem.

Since the wholly aromatic liquid crystalline polyester resin has a high melting point of at least 300 ° C, most of the organic filler powder is decomposed and thus cannot be used, and therefore, a thermally stable inorganic filler powder should be used.

The inorganic filler powder may be at least one selected from the group consisting of calcium carbonate, quartz, tridymite, attapulgite, sillimanite, heavy vermiculite, talc, mica, and carbon black.

These inorganic filler powders may be used singly or as a mixture of at least two.

The content of the inorganic filler powder is preferably from 0.1 to 5 parts by weight based on 100 parts by weight of the wholly aromatic liquid crystalline polyester resin. When the content of the inorganic filler powder is less than 0.1 parts by weight, the wholly aromatic liquid crystalline polyester resin composition cannot achieve the improvement of bubble resistance; on the contrary, if the content of the inorganic filler powder is more than 5 parts by weight, the whole The mechanical properties of the aromatic liquid crystalline polyester resin composition are changed and are not available.

In this sense, the inorganic filler contained to enhance the resistance of the bubbles is preferably in the form of a powder because the powdery inorganic particles act as a trapping agent for the radicals and contribute to the improvement of thermal stability.

The small amount of the inorganic filler powder contained in the wholly aromatic liquid crystalline polyester resin compound can improve bubble resistance without impairing thermal stability and mechanical properties, so that it can be suitably cast into an electronic device, requiring high heat resistance and being welded. The product of the connector or memory card socket.

The wholly aromatic liquid crystalline polyester resin composition according to the present invention is permeable to a wholly aromatic liquid crystalline polyester resin having a melting point of between 300 and 450 ° C and a filler for enhancing physical properties and an inorganic The filler powder is mixed, and the resulting mixture is melt-kneading to obtain a wholly aromatic liquid crystalline polyester resin compound.

For melt-kneading, a twin-screw extruder, a batch-type kneader or a mixing roll may be used, but the present invention is not limited thereto. Further, when a twin-screw extruder is used to perform melt-kneading, the barrel temperature of the extruder can be maintained between 300 and 450 ° C; in this sense, the extruder The drum refers to a "cylinder" which is a portion in which the extruded raw material (i.e., the resin composition) is melted, kneaded, and conveyed. The spiral system is installed inside the drum, so that the raw material to be extruded is conveyed forward according to the rotation of the spiral, and at the same time, the raw material to be extruded is melted by the heat conduction of the wall of the drum. Further, a lubricant may be used to accelerate the melt-kneading during the melt-kneading process.

The resin compound obtained by mixing the wholly aromatic liquid crystalline polyester resin having a high melting point with an inorganic filler powder and melt-kneading the obtained mixture in the above manner has excellent bubble resistance and does not impair fluidity and heat resistance. And mechanical characteristics, therefore suitable for use as parts of electronic devices such as connectors and memory card sockets.

Hereinafter, the present invention will be further described in detail with reference to the embodiments. However, it should be understood The examples are only intended to aid in the understanding of the invention and are not intended to limit the scope of the invention.

<Example> [Preparation Example 1]

Preparation of wholly aromatic liquid crystalline polyester resin

In a temperature-controlled batch reactor with a capacity of 100 liters, 24.4 kg of para-hydroxy benzoic acid, 10.8 kg of biphenol, 7.3 kg of terephthalic acid and 2.4 were added. Kilograms of isophthalic acid. Nitrogen gas was injected into the reactor to form an inert atmosphere in the reactor, followed by the addition of 33 kg of acetic anhydride to the reactor. Thereafter, the temperature of the reactor was raised to 150 ° C in 30 minutes, at which temperature the alcohol group of the monomer was acetated for 3 hours. Next, the temperature of the reactor is raised to 330 ° C in 6 hours, while the acetic acid product of the acetylation reaction is removed to obtain a prepolymer of the wholly aromatic liquid crystalline polyester, which is composed of These monomers are obtained by a condensation polymerization reaction. In addition, during the preparation of the prepolymer, additional acetic acid is produced as a by-product which is continuously removed during the preparation of the prepolymer as well as the acetic acid produced during the oximation reaction. Thereafter, the prepolymer was recovered from the reactor and solidified by cooling.

Next, the prepolymer of the wholly aromatic liquid crystalline polyester was pulverized to an average particle size of 1 mm, and 20 kg of the pulverized wholly aromatic liquid crystalline polyester prepolymer was placed in a rotary kiln reactor having a capacity of 100 liters. The temperature is raised to 200 ° C, which is the initial temperature of the weight reduction, and a nitrogen flow rate of 1 Nm ³ /hr is continuously administered within 1 hour, and then the temperature is raised again to 280 ° C in 10 hours, and maintained. Three hours to prepare a wholly aromatic liquid crystalline polyester resin. Subsequently, the reactor was cooled to room temperature for 1 hour, and the wholly aromatic liquid crystalline polyester resin was recovered from the reactor.

The resin is melted using a differential scanning calorimeter The point is 320 °C.

[Example 1]

The wholly aromatic liquid crystalline polyester resin obtained in Preparation Example 1, glass fiber (KCC, CS371) and carbon black (Evonik, HIBLACK 30L) were mixed at a weight ratio of 69.9:30:0.1, followed by a twin screw extruder ( L/D: 40, diameter 20 mm) was melt-kneaded. At the time of melt-kneading, the drum temperature was 350 ° C. Further, at the time of melt-kneading, a vacuum was applied to the twin-screw extruder to remove by-products. Thereafter, the melt-kneaded product was mixed by an automatic mixer (Jeil Industrail Machinery Co., Ltd.) for 10 minutes, and dried by a hot air dryer (Asung Plant) at 130 ° C for two hours. A wholly aromatic liquid crystalline polyester resin compound is obtained.

[Embodiment 2]

The wholly aromatic liquid crystalline polyester resin compound was prepared in the same manner as in Example 1, except that the mixture was obtained as the wholly aromatic liquid crystalline polyester resin obtained in Preparation Example 1, glass fiber (KCC, CS371) and talc (Dongyang Materials Industrial). , ETA #400) is replaced by a weight ratio of 68.5:30:1.5.

[Example 3]

The wholly aromatic liquid crystalline polyester resin compound was prepared in the same manner as in Example 1, except that the mixture was obtained as the wholly aromatic liquid crystalline polyester resin obtained in Preparation Example 1, glass fiber (KCC, CS371), and calcium carbonate (Dongyang Materials). Industrial, V-JAD #300) is replaced by a weight ratio of 69:30:1.

[Example 4]

The wholly aromatic liquid crystalline polyester resin compound was prepared in the same manner as in Example 1, except that the mixture was obtained as the wholly aromatic liquid crystalline polyester resin obtained in Preparation Example 1, glass fiber (KCC, CS371), talc (Dongyang Materials Industrial). , ETA #400) and carbon black (Evonik, HIBLACK 30L) is replaced by a weight ratio of 67:30:1.5:1.5.

[Example 5]

The wholly aromatic liquid crystalline polyester resin compound was prepared in the same manner as in Example 1, except that the mixture was obtained as the wholly aromatic liquid crystalline polyester resin obtained in Preparation Example 1, glass fiber (KCC, CS371), and quartz powder (Dongyang Materials). Industrial, QT #1250) is replaced by a weight ratio of 67:30:3.

[Embodiment 6]

The wholly aromatic liquid crystalline polyester resin compound was prepared in the same manner as in Example 1, except that the mixture was obtained as the wholly aromatic liquid crystalline polyester resin obtained in Preparation Example 1, glass fiber (KCC, CS371) and chalk (HOBEN). International Ltd., C325) is replaced by a weight ratio of 67:30:3.

[Comparative Example 1]

The wholly aromatic liquid crystalline polyester resin compound was prepared in the same manner as in Example 1, except that the mixture was obtained by the total aromatic liquid crystalline polyester resin obtained in Preparation Example 1 and the glass fiber (KCC, CS371) at a weight of 70:30. More than alternative.

[Comparative Example 2]

The wholly aromatic liquid crystalline polyester resin compound was prepared in the same manner as in Example 1, except that the mixture was obtained as the wholly aromatic liquid crystalline polyester resin obtained in Preparation Example 1, glass fiber (KCC, CS371), and calcium carbonate (Dongyang Materials). Industrial, V-JAD #300) and carbon black (Evonik, HIBLACK 30L) were replaced by a weight ratio of 65.5:30:3:1.5.

[assessment]

The physical properties of the wholly aromatic liquid crystalline polyester resin compound prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were tested by the methods described below.

(1) Measuring the melt viscosity

The viscosity of each compound was measured by a capillary viscometer at 330 ° C and 1/1000 s to compare the fluidity in the molten state.

(2) Measurement of tensile strength and tensile elongation

The tensile strength and tensile elongation of each wholly aromatic liquid crystalline polyester resin compound were measured in accordance with ASTM D638.

(3) Measurement of bending strength and bending elongation

The flexural strength and flexural elongation of each wholly aromatic liquid crystalline polyester resin compound were measured in accordance with ASTM D790.

(4) Measurement of heat resistance (heat distortion temperature)

The heat resistance of each wholly aromatic liquid crystalline polyester resin compound was measured in accordance with ASTM D648, and the applied pressure was 18.5 kgf/cm ² .

(5) Measurement of bubble resistance

The bubble resistance of each wholly aromatic liquid crystalline polyester was measured using a reflow oven (Samsung, RF30102) at a temperature interval of 5 ° C and an initial temperature of 250 ° C to determine the onset temperature of bubble generation.

Referring to Table 1, the following conclusions can be confirmed.

First, the wholly aromatic liquid crystalline polyester resin compound prepared in Examples 1 to 6 did not detract from its physical properties as compared with the wholly aromatic liquid crystalline polyester resin compound of Comparative Example 1 in which no inorganic filler powder was added, such as Tensile strength, tensile elongation, flexural strength, flexural elongation, and heat resistance, and high bubble resistance.

Second, in Comparative Examples 1 to 4, the addition of the inorganic filler powder increased to 5 parts by weight with respect to 100 parts by weight of the wholly aromatic liquid crystalline polyester resin, the bubble resistance was further increased and the physical properties were not impaired.

Third, in the case of Comparative Example 2, more than 5 parts by weight of the inorganic filler powder is added with respect to 100 parts by weight of the wholly aromatic liquid crystalline polyester resin, where physical properties can be confirmed Such as tensile strength, tensile elongation and bending strength loss.

The wholly aromatic liquid crystalline polyester resin composition according to the present invention exhibits excellent bubble resistance by adding a small amount of an inorganic filler powder to a wholly aromatic liquid crystalline polyester resin having a high melting point containing a filler having enhanced physical properties. It does not detract from its fluidity, heat resistance and mechanical properties. Therefore, the wholly aromatic liquid crystalline polyester resin composition according to the present invention can be used as a component of an electronic device such as a connector and a memory card socket.

Although the embodiments are disclosed herein, it is to be understood that the scope of the present invention is not to be construed as a For the scope of the patent application below.

Claims (3)

A wholly aromatic liquid crystalline polyester resin composition having improved bubble resistance, comprising: a wholly aromatic liquid crystalline polyester resin having a melting point between 300 and 450 ° C; and a filler for enhancing physical properties The filler for enhancing physical properties comprises at least one selected from the group consisting of glass fibers and carbon fibers; and an inorganic filler powder, wherein the inorganic filler powder is relative to 100 parts by weight of the wholly aromatic liquid crystalline polyester resin, It is contained in an amount of 0.1 to 1 part by weight. The wholly aromatic liquid crystalline polyester resin composition of claim 1, wherein the inorganic filler powder comprises at least one selected from the group consisting of calcium carbonate, quartz, tridymite, chalk, chert, heavy ochre, talc, mica and A group of carbon blacks. The wholly aromatic liquid crystalline polyester resin composition of claim 1, wherein the filler for enhancing physical properties contains the content of 5 to 90 parts by weight based on 100 parts by weight of the wholly aromatic liquid crystalline polyester resin.