KR20130078658A - Method of preparing wholly aromatic liquid crystalline polyester resin and wholly aromatic liquid crystalline polyester resin compound - Google Patents

Abstract

PURPOSE: A manufacturing method of a wholly aromatic liquid crystal polyester resin is provided to minimize the content of monomers in exhausted byproducts and to manufacture wholly aromatic liquid crystal polyester resins with excellent thermal resistance. CONSTITUTION: A manufacturing method of a wholly aromatic liquid crystal polyester resin comprises a step of synthesizing a wholly aromatic liquid crystal polyester prepolymer by primarily polymerizing two or more monomers in a reactor; a step of synthesizing the wholly aromatic liquid crystal polyester resin by secondarily polymerizing the prepolymer; and a step of re-supplying residues which are obtained by selectively removing acetic acids from byproducts generated during the second polymerization. The content of the monomers removed during the removal process of the acetic acid is 3 wt% or less, based on the content of byproducts.

Description

Method of preparing wholly aromatic liquid crystalline polyester resin and method of preparing compound of wholly aromatic liquid crystalline polyester resin

A method for producing a wholly aromatic liquid crystalline polyester resin and a method for producing a compound of a wholly aromatic liquid crystalline polyester resin are disclosed.

The wholly aromatic liquid crystal polyester resin is excellent in heat resistance and excellent in fluidity during melting, and is widely used mainly in the field of electronic parts as a precision injection molding material. In addition, it is excellent in dimensional stability and excellent in electrical insulation, and its use has been expanded to materials for films for electronic materials and substrates.

The wholly aromatic liquid-crystalline polyester resin is a kind of thermoplastic polymer produced by condensation polymerization, and it is important to maintain a predetermined molar ratio between monomers during the manufacture of a product.If the predetermined molar ratio between monomers is not maintained during the reaction, the polycondensation reaction may not proceed sufficiently. do.

In this case, unreacted monomers or oligomers remain in the resulting resin, and there is a problem in that gas generation and carbonization of the injection molded product occur during extrusion and injection molding. In addition, the molecular weight of the polymer is not large enough to cause a problem that the physical properties such as heat resistance or strength of the product is also lowered. One of the reasons why the molar ratio between monomers is changed during the reaction is that the sublimates of the monomers are discharged out of the reactor together with the by-products when the by-products are discharged during the reaction. In order to solve this problem, a method of controlling the discharge rate and discharge of by-products by increasing the height of the reactor condenser during the polycondensation reaction is used. In this case, the discharge rate of the by-products is delayed and the polymer polymerization reaction itself is delayed. This increases the productivity.

The first problem to be solved by the present invention is to provide a method for producing a wholly aromatic liquid-crystalline polyester resin that can minimize the content of monomers in the by-products discharged.

A second object of the present invention is to provide a method for producing a compound containing the wholly aromatic liquid-crystalline polyester resin.

In order to solve the first problem, after the first polycondensation of at least two monomers in the reactor to synthesize a wholly aromatic liquid-crystalline polyester prepolymer, the second polycondensation of the prepolymer to synthesize a wholly aromatic liquid-crystalline polyester resin As a manufacturing method of the wholly aromatic liquid-crystalline polyester resin containing,

It provides a method for producing a wholly aromatic liquid crystal polyester resin comprising the step of re-feeding the residue obtained by selectively removing acetic acid from the first by-product generated in the second condensation polymerization process in the reactor.

In order to solve the first problem, after the first polycondensation of at least two monomers in the reactor to synthesize a wholly aromatic liquid-crystalline polyester prepolymer, the second polycondensation of the prepolymer to synthesize a wholly aromatic liquid-crystalline polyester resin ;

A method for producing a wholly aromatic liquid crystal polyester resin compound comprising the step of mixing and melt-kneading the synthesized wholly aromatic liquid crystal polyester resin and a filler,

It provides a method for producing a wholly aromatic liquid-crystalline polyester resin compound comprising the step of re-feeding the residue obtained by selectively removing acetic acid from the first by-product generated in the second polycondensation process in the reactor.

By applying a separate column for fractional distillation during the polycondensation reaction, acetic acid, which is a by-product, is smoothly discharged while the sublimates of the monomer are returned to the reactor to participate in the polymerization reaction. There is almost no generation of gas during post-processing without problems due to unreacted monomers, and it is possible to prepare a wholly aromatic liquid crystal polyester resin having excellent heat resistance and a compound including the same.

Hereinafter, a method of preparing a wholly aromatic liquid crystal polyester resin and a compound of a wholly aromatic liquid crystal polyester resin according to one embodiment of the present invention will be described in detail.

One embodiment of the present invention, after the first polycondensation of at least two monomers in the reactor to synthesize a wholly aromatic liquid-crystalline polyester prepolymer, the second polycondensation of the prepolymer to synthesize a wholly aromatic liquid-crystalline polyester resin; As a manufacturing method of the wholly aromatic liquid-crystalline polyester resin containing,

It provides a method for producing a wholly aromatic liquid-crystalline polyester resin comprising the step of re-feeding the residue obtained by selectively removing acetic acid from the by-product generated in the second polycondensation process in the reactor.

During the second polycondensation, acetic acid, which is a by-product of the polycondensation reaction, is discharged to the outside of the reactor to increase reactivity. In this case, monomer as a by-product is also discharged to the outside along with acetic acid as a by-product. The balance between the molar ratios of the liver is broken so that the unreacted monomers remain and the polyester resin having a low molecular weight is polymerized.

In order to prevent this, by selectively discharging acetic acid, it is possible to reduce the content of remaining unreacted monomers and to increase the molecular weight of the polyester resin as a result of polymerization.

In order to selectively discharge the acetic acid, in the present invention, by applying a fractionation tube at the bottom of the condenser for discharging the by-product of the second condensation polymerization reaction, the acetic acid as a by-product is normally discharged by separating and discharging each component through fractional distillation, Other components, for example, the raw material monomer, may be fed back into the reactor to participate in the reaction.

The selective removal process of acetic acid as described above can be carried out by selectively passing the acetic acid by passing the by-product discharged from the reactor along the fractionation tube, the distillation column can be used as the fractionation tube usable at this time, the non-lux Examples include, but are not limited to, a vigreux column, a hampel column, a widget column, a snyder column, and the like, but are not limited thereto. Any pipe can be used without restriction.

The fractionation tube is designed to have the effect of continuing partial condensation of steam and partial vaporization of condensate, and the contact surface between the steam and the condensate is large so that the thermal equilibrium can be easily reached. Thus, acetic acid with a relatively low boiling point is vaporized and discharged normally, and monomers with a much higher sublimation temperature do not reach the sublimation temperature due to contact between air and condensate, and are returned to the reactor.

By selectively removing acetic acid in the by-products, the molar ratio balance between monomers as raw materials is maintained, and by-products are stably discharged to proceed the polymerization reaction. As a result, unreacted monomers in the reactor are reduced, and the polymerization reaction is stably maintained. It advances and it becomes possible to obtain fully aromatic liquid crystalline polyester resin of sufficient molecular weight. Therefore, the production of the compound using the resin, or during the post-processing, such as extrusion or injection, the generation of gas is reduced and the polymerization of the resin is also increased to obtain the effect of improving the heat resistance.

The fractionation tube is connected to the condensate of the condenser connected to the second condensation polymerization reactor to be introduced into the middle or lower portion of the fractionation tube, and to selectively remove acetic acid from the by-products discharged during the second condensation polymerization process. Will perform.

The monomer separated in this selective removal process of acetic acid is fed back to the reactor, but the fine content of the monomer may be discharged together with the acetic acid. At this time, the content of the monomer discharged with acetic acid may have a range of 3% by weight or less, for example, 0.001 to 3% by weight based on the content of acetic acid-containing by-products. When it exceeds 3 weight%, there exists a possibility that the content of the unreacted monomer remain | survive in a result may become high, and the possibility of obtaining the polyester resin with a small molecular weight may become high.

The second condensation polymerization process may be performed at a temperature range of 200 ° C. to 400 ° C. for 0.1 to 10 hours.

At least one or more of aromatic diols, aromatic dicarboxylic acids and aromatic hydroxy carboxylic acids can be used as the monomer used in the first condensation polymerization step in the method for producing the wholly aromatic liquid crystal polyester resin of the present invention. In addition, the monomer may further include at least one or more of aromatic diamine and aromatic amino carboxylic acid.

As the condensation polymerization method, solution condensation polymerization, bulk condensation polymerization may be used. In addition, in order to promote the polycondensation reaction, a monomer (ie, acylated monomer) which is pretreated with a chemical such as an acylating agent (particularly, an acetylating agent) to increase reactivity may be used.

In addition, a metal catalyst may be used to promote the reaction in the polycondensation reaction. Examples of such metal catalysts include alkali metals such as lithium, sodium and potassium; Or oxides, hydroxides, chlorides, etc. of such alkali metals.

Since the wholly aromatic liquid crystal polyester resin prepared by the method for producing an wholly aromatic liquid crystal polyester resin according to an embodiment of the present invention having the above structure does not contain by-products and unreacted monomers without increasing the capacitor height separately, It does not generate gas during post-processing such as extrusion or injection, and has excellent heat resistance because molecular weight increases.

The wholly aromatic liquid crystal polyester resin prepared by the method for producing an wholly aromatic liquid crystal polyester resin according to one embodiment of the present invention having the above configuration has a melting temperature of 310 ° C. or higher, for example, because the heat resistance is increased as described above. It may have a melting temperature of 315 ℃ to 350 ℃.

Meanwhile, the prepared wholly aromatic liquid crystal polyester resin may include various repeating units in a chain, and may include, for example, the following repeating units:

(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-

In the above formula, Ar is phenylene or a derivative thereof, biphenylene or a derivative thereof, or a triphenylene derivative, a naphthalene or a derivative thereof, Assen or a derivative thereof, or they are substituted or unsubstituted C _{1 -6} alkyl alkylene, -NH-, -O-, and represents an aromatic compound connected to at least one of -S-, at least one hydrogen is present in the Ar is a halogen atom, C _{1 -6} alkyl, hydroxy, carboxyl, an amino group, a nitro group It may be substituted with various substituents, such as cyano group.

In addition, another embodiment of the present invention provides a method for producing a wholly aromatic liquid crystal polyester resin compound comprising the above-mentioned method for producing a wholly aromatic liquid crystal polyester resin.

Specifically, the manufacturing method of the wholly aromatic liquid crystal polyester resin compound

Synthesizing the wholly aromatic liquid crystal polyester prepolymer by first polycondensing at least two monomers in the reactor, and then synthesizing the wholly aromatic liquid crystal polyester resin by second polycondensation of the prepolymer; And mixing and melt kneading the synthesized wholly aromatic liquid-crystalline polyester resin and the additive in a predetermined ratio, and re-feeding the residue obtained by selectively removing acetic acid from the by-product generated in the second condensation polymerization process. Preparing a compound of the wholly aromatic liquid-crystalline polyester resin comprising the step.

The additive may comprise an inorganic filler and / or an organic filler. The inorganic filler may include glass fiber, talc, calcium carbonate, mica, clay or a mixture of two or more thereof, and the organic filler may include carbon fiber. The inorganic filler and the organic filler play a role of improving the mechanical strength of the injection molded article during the injection molding of the wholly aromatic liquid crystal polyester resin compound.

A batch kneader, a twin screw extruder or a mixing roll may be used for the melt kneading. Further, for the purpose of smooth melt-kneading, an activator may be used for melt-kneading.

Since the wholly aromatic liquid crystal polyester resin compound prepared by the method for producing an wholly aromatic liquid crystal polyester resin compound according to the exemplary embodiment of the present invention having the above structure does not substantially contain unreacted monomers, gas may be injected during injection molding. Does not generate and does not produce carbide.

Since the above-mentioned wholly aromatic liquid crystal polyester resin compound has increased heat resistance, it has a load bending temperature (HDT) of 250 ° C. or higher, and has a load bending temperature of 260 to 300 ° C., for example. In addition, the wholly aromatic liquid crystal polyester resin compound may have a melting temperature of 310 ℃ or more, for example, 315 ℃ to 350 ℃.

In the present specification, 'does not contain unreacted monomer' not only contains no unreacted monomer, but also carbonized on the surface of the injection-molded product after injection processing of the resin compound made of the wholly aromatic liquid-crystalline polyester resin. It also means including an extremely small amount of unreacted monomer to the extent that no trace is observed.

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

Example 1

1. Preparation of wholly aromatic liquid crystalline polyester resin

42.0 mol of 4-hydroxy benzoic acid, 29.0 mol of hydroquinone, 12.0 mol of terephthalic acid, 17.0 mol of 2,6-naphthalene dicarboxylic acid, and acetic anhydride in a stirring reactor capable of torque measurement and a 10 liter batch reactor capable of temperature control. Into the mol% (relative to hydroxyl equivalent weight) and 70 ppm of potassium acetate (based on K + for the production resin) as a catalyst, while stirring using a stirrer and heated until the temperature of the reaction mass reaches 140 ℃, held for 2 hours, The alcohol functional group of the monomer was acetylated. When condensation and removal of acetic acid generated as a by-product from the end of the acetylation reaction, a non-lux column (length 250 mm) is applied to the bottom of the condenser, and the temperature of the reactant is raised to 310 ° C. at a rate of 0.6 ° C. per minute. When reached, the resin was discharged after maintaining the temperature of the reactor heater for 2 hours.

2. Preparation of Omniaromatic Liquid Crystalline Polyester Compound

The compound was manufactured by melt-kneading | mixing the wholly aromatic liquid-crystalline polyester resin obtained by the said method, and glass fiber in the ratio of 5: 5, using the twin screw extruder of L / D40 and 20phi. Vacuum was extruded to remove byproducts during compound preparation.

 [Example 2]

Prepared in the same manner as in Example 1, but the reaction was carried out by applying a non-lux column of 100mm length.

Comparative Example 1

Preparation was carried out in the same manner as in Example 1, except that the reaction was carried out by applying only a capacitor except a non-lux column.

Comparative Example 2

Preparation was carried out in the same manner as in Example 1, except that the reaction was carried out by raising the height of the condenser 1.5 times except for the non-lux column.

[Experimental Example]

(Measurement of monomer content in byproducts)

In Example 1 and 2 and Comparative Examples 1 and 2 when the discharge of the resin is completed, the recovered acetic acid by-product was analyzed by gas chromatography to determine the monomer content in acetic acid, the content is shown in Table 1 below.

(Melting temperature measurement)

Melting temperature was measured for each of the wholly aromatic liquid crystal polyester resin compounds obtained in Examples 1 and 2 and Comparative Examples 1 and 2 while heating up at 20 ° C./min using DSC, and the results are shown in Table 1 below.

(Measurement of Load Bending Temperature)

Heat distortion temperature (HDT) of each of the wholly aromatic liquid crystal polyester resins prepared in Examples 1 and 2 and Comparative Examples 1 and 2 was measured according to ASTM D648, and the results are shown in Table 1 below.

(Observation of gas during injection of resin compound and carbonization of injection molded product)

In order to measure the load deflection temperature of each of the wholly aromatic liquid crystal polyester resin compounds prepared in Examples 1 and 2 and Comparative Examples 1 and 2, each of the resin compounds was injected into a molding machine (FANUC ROBOSHOT 2000i-50B). When preparing each specimen by injection, the specimen was visually observed whether gas was generated in the specimen fabrication process and whether the produced specimen (ie, injection molded product) was carbonized and is shown in Table 1 below. When gas was generated, it was indicated by ○, when a small amount was generated by △, and when not generated, by x. In addition, when each specimen was carbonized, (circle) and when it was not carbonized, it was represented by x.

division Sorting tube length (mm) Condenser height (times) Monomer content in by-products (% by weight) Melting temperature
(℃) Load deflection
Temperature (℃) Gas generation during extrusion Psalm Carbonization Example 1 250 1.0 0.95 319 284 Never Not carbonized Example 2 100 1.0 1.89 318 280 Never Not carbonized Comparative Example 1 not used 1.0 7.76 315 272 Occurred Carbonized Comparative Example 2 not used 1.5 3.45 319 278 Small amount occurrence Carbonized

As shown in Table 1, the wholly aromatic liquid-crystalline polyester resin compound according to Examples 1 and 2 is less than 2% by weight of the monomer content in acetic acid by-product, less than the monomer content of Comparative Examples 1 and 2, and thus as a by-product It can be seen that acetic acid was selectively removed. It can be seen that the reason that the monomer content in the by-product in Comparative Example 2 is less than that of Comparative Example 1 is due to the increase of the condenser height by 1.5 times.

The melting temperature and the load bending temperature of the wholly aromatic liquid crystal polyester resin compound according to Example 1 and Example 2 can be seen that the melting temperature and the load bending temperature are both higher than Comparative Examples 1 and 2, through this heat resistance It can be seen that the improvement.

In addition, in Examples 1 and 2, no gas was generated during the extrusion and no carbonization trace was found, indicating that no unreacted monomer remained. On the other hand, in the specimens of Comparative Examples 1 and 2, gas was generated and carbonization traces were generated, indicating that unreacted monomer remained.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (11)

A first polycondensation of at least two monomers in the reactor to synthesize a wholly aromatic liquid crystal polyester prepolymer, and then a second polycondensation of the prepolymer to synthesize a wholly aromatic liquid crystal polyester resin. As a manufacturing method of resin,
Re-feeding the residue obtained by selectively removing acetic acid from the by-products generated in the second condensation polymerization process into the reactor. The method of claim 1,
The selective removal of acetic acid is a method of producing a wholly aromatic liquid crystal polyester resin comprising the step of selectively discharging acetic acid from the fractionation pipe by-product discharged from the reactor. The method of claim 1,
Method for producing a wholly aromatic liquid-crystalline polyester resin, wherein the dividing tube is a distillation column. The method of claim 2,
The dividing tube is connected to the condensate of the condenser connected to the second condensation polymerization reactor is connected to the middle or lower portion of the dividing tube is connected to the manufacturing method of the wholly liquid crystal polyester resin. The method of claim 1,
The selective removal of acetic acid is carried out simultaneously with the second condensation polymerization process. The method of claim 1,
The method of producing a wholly aromatic liquid crystal polyester resin in which the content of the monomers removed together in the selective removal process of acetic acid is in the range of 3% by weight or less based on the content of by-products. The method of claim 1,
Method for producing a wholly aromatic liquid-crystalline polyester resin is the second condensation polymerization process is carried out for 0.1 to 10 hours in the temperature range of 300 ℃ to 400 ℃. The method of claim 1,
The said monomer is the manufacturing method of the wholly aromatic liquid crystalline polyester resin which is at least 1 sort (s) or more of aromatic diol, aromatic dicarboxylic acid, and aromatic hydroxy carboxylic acid. The method of claim 8, wherein
The monomer is a method for producing a wholly aromatic liquid-crystalline polyester resin further comprises at least one or more of aromatic diamine and aromatic amino carboxylic acid. Synthesizing the wholly aromatic liquid crystal polyester prepolymer by first polycondensing at least two monomers in the reactor, and then synthesizing the wholly aromatic liquid crystal polyester resin by second polycondensation of the prepolymer;
A method for producing a wholly aromatic liquid crystal polyester resin compound comprising the step of mixing and melt-kneading the synthesized wholly aromatic liquid crystal polyester resin and a filler,
And re-feeding the residue obtained by selectively removing acetic acid from the first by-product generated in the second polycondensation step into the reactor. The method of claim 10,
The filler is a method of producing a wholly aromatic liquid-crystalline polyester resin compound is at least one of glass fiber, talc, calcium carbonate, mica, clay and carbon fiber.