KR20130047260A - Wholly aromatic liquid crystalline polymer resin compound with enhanced strength and electronic compartments made from the same - Google Patents

Abstract

PURPOSE: A wholly aromatic liquid crystal polymer resin composition is provided to have high strength without degrading flowability and to have excellent heat resistance. CONSTITUTION: A wholly aromatic liquid crystal polymer resin composition comprises 2-100.0 parts by weight of a carbon fiber based on 100.0 parts by weight of a wholly aromatic liquid crystal polymer resin with a melting point of 300-450 °C. The carbon fiber is a acryl-based, rayon-based, lignin-based, or pitch-based carbon fiber. The resin composition comprises 3-900 parts by weight of one or more inorganic filler selected from glass fiber, talc, mica, calcium carbonate, and clay, based on 100.0 parts by weight of the wholly aromatic liquid crystal polymer resin.

Description

Wholly aromatic liquid crystalline polymer resin compound with enhanced strength and electronic compartments made from the same}

The present invention relates to a wholly aromatic liquid crystal polymer resin composition having high strength characteristics. The present invention also relates to an electronic device manufactured from the resin composition.

The wholly aromatic liquid crystal polymer resin has excellent heat resistance and dimensional stability, and is excellent in fluidity during melting, and thus has been widely used in the field of electronic parts as a precision injection molding material.

The wholly aromatic liquid crystal polymer resin is a kind of thermoplastic polymer produced by condensation polymerization, and is prepared in the form of a composition by kneading with an inorganic filler such as glass fiber or talc and extruding. In addition, the resin composition prepared as described above is processed into a product through an injection process.

In particular, the wholly aromatic liquid crystal polymer resin composition reinforced with various organic / inorganic fillers has high heat resistance, excellent dimensional stability, electrical insulation, and mechanical properties, so that it can be used for connectors and other memory card sockets of electronic products. The use is expanding.

Connectors of electronic products and other memory card socket products are thin in structure, and in recent years, due to the miniaturization of electronic products, even thinner and smaller types of connectors and memory card socket products are required. Such thin and small connector and socket products may be broken or changed when a force or an impact is applied from the outside. Therefore, the resin composition used for molding a product such as a connector or a socket is required to be developed with a material having improved strength so that cracking or deformation does not occur even when an external impact occurs.

 On the other hand, in the case of increasing the degree of polymerization in the polymerization process of the wholly aromatic liquid-crystalline polymer resin that is the main raw material of the resin composition in order to produce a resin composition that can sufficiently satisfy the mechanical properties so that the form of the product is not deformed or damaged by external force, In general, the fluidity of the resin is lowered, so that molding is difficult, and the elasticity of the resin is lowered, so that the molded product is easily broken.

Therefore, the development of the wholly aromatic liquid crystal polymer resin composition which has high strength characteristic is calculated | required without the other physical property of the resin composition containing fluidity deteriorating.

The present invention relates to a wholly aromatic liquid crystal polymer resin composition for use as a component material for a connector and a memory card socket, comprising a wholly aromatic liquid crystal polymer resin composition having high strength characteristics in terms of mechanical properties and not deteriorating fluidity and having excellent heat resistance. It aims to provide.

Moreover, an object of this invention is to provide the electronic device which has the characteristic strong against external shock manufactured from the said resin composition.

The present invention provides an wholly aromatic liquid crystal polymer resin composition comprising 2 to 100 parts by weight of carbon fiber with respect to 100 parts by weight of the wholly aromatic liquid crystal polymer resin having a melting point of 300 to 450 ℃.

Preferably, the carbon fiber is acrylic carbon fiber, rayon carbon fiber, lignin carbon fiber or pitch carbon fiber.

Preferably, the wholly aromatic liquid crystal polymer resin is at least one aromatic selected from the group consisting of aromatic diols, aromatic diamines, aromatic hydroxyamines, aromatic dicarboxylic acids, aromatic hydroxy carboxylic acids and aromatic amino carboxylic acids. It is synthesize | combined from the polycondensation reaction of a compound monomer.

Preferably, the aromatic compound includes a form in which substituted or unsubstituted phenylene, biphenylene, naphthalene or two phenylenes are connected by carbon or non-carbon elements.

Preferably, the resin composition comprises at least one inorganic filler selected from the group consisting of glass fibers, talc, mica, calcium carbonate and clay.

Preferably, the inorganic filler is included in 3 to 900 parts by weight based on 100 parts by weight of the wholly aromatic liquid crystal polymer resin.

The present invention provides an electronic device, which is produced from the wholly aromatic liquid crystal polymer resin composition.

Preferably, the electronic device is a connector or a memory card socket.

The resin composition of the present invention comprising a wholly aromatic liquid crystal polymer resin having a high melting point and carbon fibers has high strength characteristics without deteriorating fluidity and heat resistance. Accordingly, the composition of the present invention can be suitably used for molding small sized connectors and memory card sockets according to a thin structure vulnerable to external impact and in particular, a tendency to miniaturize the product.

The present invention comprises a wholly aromatic liquid crystal polymer resin and a carbon fiber having a melting point of 300 to 450 ℃ in order to provide a wholly aromatic liquid crystal polymer resin composition to improve the mechanical strength and at the same time maintain a level equivalent to the conventional in terms of heat resistance and fluidity It provides a wholly aromatic liquid crystal polymer resin composition, characterized in that.

Specifically, the resin composition includes 2 to 100 parts by weight of carbon fiber based on 100 parts by weight of the wholly aromatic liquid crystal polymer resin.

The wholly aromatic liquid crystal polymer resin used in the resin composition of the present invention has a melting point of 300 to 450 ° C., which is a resin having a high melting point, and thus the resin composition of the present invention has excellent heat resistance.

In the present invention, the use of a resin having a high melting point of 300 ° C. or higher as the wholly aromatic liquid crystal polymer resin, when the melting point is less than 300 ° C., is difficult to process due to excessive fluidity in a high temperature processing area of 330 ° C. or higher for forming an electronic product. This is because if the melting point exceeds 450 ° C., it will be difficult to have sufficient fluidity in the high temperature processing region and the processing will be difficult.

In the present invention, in order to provide a resin composition with improved mechanical properties, the carbon fiber is mixed with the resin, and the carbon fiber usable in the present invention is acrylic carbon fiber, rayon carbon fiber, lignin carbon fiber, pitch carbon fiber. All carbon fibers used for general plastic reinforcement can be used in the present invention. Of these, acrylic carbon fibers are preferred because they have the highest level of rigidity and light weight.

Acrylic carbon fiber is a spinning solution containing a PAN polymer that is a precursor of the spinning solution by the method of wet spinning, dry spinning or dry wet spinning to obtain a precursor fiber, and then heated it under an oxidizing atmosphere at a temperature of 200 to 400 ℃ It is a substance produced industrially by converting into chlorinated fiber and carbonizing by heating in an inert atmosphere at a temperature of at least 1000 ° C.

The carbon fiber used in the present invention may be in any form, for example, a chopped strand spinning yarn or a woven fabric.

Various methods can be used to mix the carbon fiber with the wholly aromatic liquid crystal polymer resin. For example, mixing may be achieved by supplying a chopped strand carbon fiber having a length of 3 to 6 mm and a wholly aromatic liquid crystal polymer resin to a melt extruder separately and then mixing them together. Alternatively, they may be premixed beforehand in a mixer such as a mixer or ribbon blender and then fed to the melt extruder. As another method, the dried carbon fibers may be fed directly to the melt extruder and mixed with the wholly aromatic liquid crystal polymer resin. Therefore, as long as the mixing ratio of the carbon fiber and the wholly aromatic liquid crystal polymer resin in the composition finally obtained in the present invention can be achieved, the order and method of mixing the two components are not limited.

Regarding the mixing ratio of the carbon fibers, when less than 2 parts by weight of carbon fibers are mixed with respect to 100 parts by weight of the wholly aromatic liquid crystal polymer resin, the reinforcing effect is insignificant, and a resin composition having sufficient mechanical strength cannot be prepared. When the amount is mixed in an amount of more than 100 parts by weight, the finally obtained resin composition is difficult to be melted and mixed into a homogeneous mixture, and the melt fluidity is remarkably lowered to show poor moldability at the time of injection molding.

In the resin composition comprising the above-described carbon fiber of the present invention, it exhibits excellent heat resistance in a wide temperature range by synergy between improved heat resistance and reinforcing effect of carbon fiber.

In addition, in the present invention, as described above, the melting point uses a wholly aromatic liquid crystal polymer resin in the range of 300 to 450 ° C., but carbon fiber is preferably included in the resin composition of the present invention because it is a material that ensures thermal stability even at a high temperature of 300 ° C. or higher. Can be used.

In the wholly aromatic liquid crystal polymer resin composition of the present invention, by including the wholly aromatic liquid crystal polymer resin and carbon fiber having a high melting point as described above, it can be secured to a desirable level while having high strength properties and heat resistance.

The wholly aromatic liquid crystal polymer resin included in the resin composition of the present invention may be prepared by the following steps:

(a) synthesizing the prepolymer of the wholly aromatic liquid crystal polymer resin by polycondensing at least two aromatic compound monomers, and

(b) synthesizing the wholly aromatic liquid crystal polymer resin by solid-phase polycondensation of the prepolymer.

The monomer of the aromatic compound used in the condensation polymerization reaction in the step (a) is used in the production of a resin by a conventional condensation polymerization reaction, at least one selected from the group consisting of aromatic diols, aromatic diamines and aromatic hydroxyamines. Compound and aromatic dicarboxylic acid. In addition, the aromatic hydroxy carboxylic acid or aromatic amino carboxylic acid may be used by condensation polymerization, or these may be additionally included in the polycondensation reaction of the diol, diamine or hydroxyamine with dicarboxylic acid to carry out the reaction of step (a). You can proceed.

As the synthesis method of step (a), a solution condensation polymerization method and a bulk condensation polymerization method may be used as a method used for preparing a resin by a conventional condensation polymerization reaction.

In addition, in step (a), the monomers are pretreated with a chemical such as an acylating agent (particularly an acetylating agent) to increase the reactivity (ie, in the form of an acylated monomer) in order to promote the polycondensation reaction. Can be used for

Next, for the solid phase polycondensation reaction of the step (b) it is subjected to condensation polymerization while providing heat to the prepared prepolymer. Such a heat providing method includes a method using a heating plate, a method using hot air, or a method using a high temperature fluid. In addition, the purge or vacuum using an inert gas to remove the by-products generated during the solid state polycondensation reaction can be carried out.

The wholly aromatic liquid crystal polymer resin may contain various repeating units in the polymer chain as follows according to the aromatic compound monomer used in the polymerization reaction:

(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 hydroxyamines:

[-HN-Ar-O-]

(4) repeating units derived from aromatic dicarboxylic acids:

[-OC-Ar-CO-]

(5) repeating units derived from aromatic hydroxy carboxylic acids:

[-O-Ar-CO-]

(6) repeating units derived from aromatic amino carboxylic acids:

[-HN-Ar-CO-]

Ar in the above formulas (1) to (6) may be in the form of substituted or unsubstituted phenylene, biphenylene, naphthalene or two phenylenes connected by carbon or non-carbon elements. Preferably, the substituent may be an aliphatic substituent having 1 to 6 carbon atoms, the non-carbon linking element may be nitrogen.

Since the resin composition of this invention contains carbon fiber, it is possible to have a high strength characteristic, without the fluidity and heat resistance of a composition being deteriorated. Therefore, the wholly aromatic liquid crystal polymer resin composition of the present invention can be suitably used for molding a product for a thin structure and a small connector and a memory card socket which are particularly susceptible to external impact.

The carbon fiber included in the resin composition of the present invention is preferably used in an amount of 2 to 100 parts by weight based on 100 parts by weight of the resin in consideration of the improvement in mechanical strength and the dispersibility in the wholly aromatic liquid crystal polymer resin and the fluidity of the resin composition. As described above, when the carbon fiber is used in an amount of less than 2 parts by weight, it is difficult to expect a sufficient improvement in mechanical strength in the wholly aromatic liquid crystal polymer resin composition, and when used in an amount exceeding 100 parts by weight, It is not preferable because acidity and fluidity deterioration of the composition occur to make kneading processing of the resin composition difficult.

In addition, the resin composition of the present invention may be used by adding a conventional inorganic filler in addition to the wholly aromatic liquid crystal polymer resin and carbon fiber to improve the mechanical properties and heat resistance of the resin composition.

The inorganic filler is at least one selected from the group consisting of glass fibers, talc, mica, calcium carbonate and clay.

The content of the inorganic filler is preferably used in the range of 3 to 900 parts by weight based on 100 parts by weight of the wholly aromatic liquid crystal polymer resin. When the total content of the inorganic filler is less than 3 parts by weight based on 100 parts by weight of the wholly aromatic liquid crystal polymer resin, the wholly aromatic liquid crystal polymer resin composition is difficult to achieve sufficient mechanical strength, and when it exceeds 900 parts by weight, the wholly aromatic liquid crystal polymer resin The fluidity and moldability of the composition are lowered.

The present invention is a method for producing the wholly aromatic liquid-crystalline polymer resin composition, by mixing 2 to 100 parts by weight of carbon fiber with respect to 100 parts by weight of the wholly aromatic liquid-crystalline polymer resin having a melting point of 300 to 450 ℃, to prepare a mixture, A method of melt kneading a mixture is provided. At this time, the mixture further comprises at least one inorganic filler selected from the group consisting of glass fibers, talc, mica, calcium carbonate and clay in the range of 3 to 900 parts by weight based on 100 parts by weight of the wholly aromatic liquid crystal polymer resin. Can be used.

In addition, a double screw extruder, a batch kneader or a mixing roll may be used for melt kneading the mixture including the resin and carbon fiber. In particular, when performing melt kneading using a twin screw extruder, the barrel temperature of the extruder can be maintained at 330 to 450 ℃. Here, the barrel of the extruder is a part for melting, kneading and transporting the extrusion raw material (that is, a mixture of resin and nanoclay, etc.) and is also referred to as a cylinder. The inside of the barrel is equipped with a screw so that the extrusion raw material is transferred forward by two rotations of the screw, and at the same time the extrusion raw material is melted due to heat conducted from the barrel wall surface. In addition, a lubricant may be additionally used during melt kneading for smooth melt kneading of the extrusion raw material.

The present invention provides an electronic device manufactured from the resin composition produced by the above production method. Examples of such electronic devices include thin structures and particularly small connectors and memory card sockets.

The invention will be described in detail through the following examples. However, this is to facilitate the understanding of the invention, and therefore the present invention should not be considered as being limited thereto.

Example  One

(1) Preparation of wholly aromatic liquid crystal polymer resin

In a 100-liter batch reactor with temperature control, 24.4 kg para hydroxy benzoic acid (UENO Fine Chemirals), 10.8 kg biphenol (Songwon), 7.3 kg terephthalic acid (Samsung Petrochemical) and isophthalic acid (Perstorp) 2.4 kg was added and nitrogen gas was injected to make the internal space of the reactor inactive, and then 33 kg of acetic anhydride (CELANESE) was further added to the reactor. Thereafter, the reactor temperature was raised to 150 ° C. over 30 minutes, and then the alcohol group (hydroxy group) of the monomers was acetylated for 3 hours at this temperature.

Subsequently, the temperature of the reactor was raised to 330 ° C. over 6 hours while removing the acetic acid generated in the acetylation reaction, thereby preparing a prepolymer of the wholly aromatic liquid crystal polymer resin by the polycondensation reaction of the monomers. Acetic acid is further generated as a by-product during the preparation of the prepolymer, and the acetic acid is continuously removed during the preparation of the prepolymer similarly to the acetic acid produced in the acetylation reaction.

After completion of the reaction, the prepolymer was recovered from the reactor and cooled and solidified. Thereafter, the prepolymer was pulverized to an average particle diameter of 1 mm, 20 kg of the pulverized prepolymer was introduced into a rotary kiln reactor having a capacity of 100 liters, and nitrogen was continuously flowed at a flow rate of 1 Nm 3 / hour, followed by a weight loss start temperature of 200 ° C. in 1 hour. After raising over temperature, it fully heated up to 280 degreeC over 10 hours, and maintained for 3 hours, and prepared the wholly aromatic liquid-crystal polymer resin.

Subsequently, after cooling the reactor to room temperature over 1 hour, the wholly aromatic liquid crystal polymer resin was recovered from the reactor. The melting point of the resin measured using a differential scanning calorimeter was 320 ° C.

(2) Preparation of wholly aromatic liquid crystal polymer resin composition

The whole aromatic liquid crystal polymer resin, glass fiber (Sungjinjin, MF75-NL) and carbon fiber (Toho Tenax, HT C493) prepared in step (1) were mixed in a ratio of 85: 10: 5 by weight in a ratio of two axes Melt kneading was carried out using an extruder (L / D: 40, diameter: 20 mm). The barrel temperature of the extruder during the melt kneading was 350 ° C. At the same time as melt kneading, by-products were removed by applying a vacuum to a twin screw extruder.

Subsequently, the melt-kneaded mixture was mixed for 10 minutes with an automatic mixer (first industrial equipment), and dried at 130 ° C. for 2 hours with a hot air dryer (product of anneal PLANT) to prepare an wholly aromatic liquid crystal polymer resin composition.

Example  2

Change the mixing ratio of the wholly aromatic liquid crystal polymer resin, glass fiber (Seongjinjin, MF75-NL) and carbon fiber (Toho Tenax, HT C493) prepared in step (1) of Example 1 to 80:10:10 A wholly aromatic liquid crystal polymer resin composition was prepared in the same manner as in Example 1, except that it was used.

Comparative example  One

In the same manner as in Example 1, except that the wholly aromatic liquid crystal polymer resin and glass fiber (Seongjinjin, MF75-NL) prepared in step (1) of Example 1 were used at 90:10 by weight. The wholly aromatic liquid crystal polymer resin composition was prepared.

Evaluation of physical properties of the resin composition

The physical properties of each of the wholly aromatic liquid crystal polymer resin compositions prepared in Examples and Comparative Examples were measured by the following method.

(Measurement of Melt Viscosity)

About the resin composition, the viscosity was measured on the conditions of 330 degreeC and 1 / 1000s using the capillary viscometer, and the fluidity | liquidity of a molten state was compared.

(Measurement of tensile strength and tensile elongation)

Tensile strength and tensile elongation of the resin composition were measured according to ASTM D638.

(Measurement of Flexural Strength and Flexural Elongation)

Flexural strength and flexural elongation of the resin composition were measured according to ASTM D790.

(Measurement of heat resistance (heat deformation temperature))

The heat resistance of the resin composition was measured according to ASTM D648. At this time, the given pressure was 18.5 kgf / cm 2.

Physical properties measured for the resin composition are summarized in Table 1 below.

From the above Table 1, the wholly aromatic liquid crystal polymer resin compositions prepared in Examples 1 and 2 were similar in melt viscosity and heat resistance properties as compared to the resin compositions prepared in Comparative Example 1, but the tensile strength and flexural strength were improved. In addition, when compared with Examples 1 and 2, the increase in the amount of carbon fiber used showed a more pronounced effect of mechanical strength.

On the other hand, when carbon fiber was used in an excess exceeding 100 parts by weight with respect to 100 parts by weight of the resin, the fluidity of the mixture was drastically lowered, making it impossible to prepare the composition.

From the above results, it can be seen that by using a predetermined amount of carbon fibers in the omnidirectional liquid crystal polymer resin composition, mechanical strength can be effectively improved while maintaining fluidity suitable for molding the composition.

Claims (8)

A wholly aromatic liquid crystal polymer resin composition comprising 2 to 100 parts by weight of carbon fiber with respect to 100 parts by weight of wholly aromatic liquid crystal polymer resin having a melting point of 300 to 450 ℃. In claim 1,
The carbon fiber is a wholly aromatic liquid crystal polymer resin composition, characterized in that the acrylic carbon fiber, rayon-based carbon fiber, lignin-based carbon fiber or pitch-based carbon fiber. In claim 1,
The wholly aromatic liquid-crystalline polymer resin is at least one aromatic compound monomer selected from the group consisting of aromatic diols, aromatic diamines, aromatic hydroxyamines, aromatic dicarboxylic acids, aromatic hydroxy carboxylic acids and aromatic amino carboxylic acids. It is synthesize | combined from polycondensation reaction, The whole aromatic liquid crystal polymer resin composition characterized by the above-mentioned. 4. The method of claim 3,
The aromatic compound is a wholly aromatic liquid crystal polymer resin composition, characterized in that the substituted or unsubstituted phenylene, biphenylene, naphthalene or two phenylene form comprising a carbon or an element other than carbon. In claim 1,
The resin composition is a wholly aromatic liquid crystal polymer resin composition, characterized in that it comprises at least one inorganic filler selected from the group consisting of glass fibers, talc, mica, calcium carbonate and clay. The method of claim 5,
The inorganic filler is an wholly aromatic liquid crystal polymer resin composition, characterized in that it comprises 3 to 900 parts by weight based on 100 parts by weight of the wholly aromatic liquid crystal polymer resin. The electronic device manufactured from the said wholly aromatic liquid-crystal polymer resin composition in any one of Claims 1-6. In claim 7,
The electronic device is an electronic device, characterized in that the connector or memory card socket.