JP2015120851A - Production method of liquid crystalline polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a liquid crystalline polyester by fusing and polymerizing a source monomer, pulverizing the obtained fused-polymerized material, and then polymerizing the material in a solid phase, in which the pulverized material is prevented from sintering at the time of solid-phase polymerization.SOLUTION: The production method of a liquid crystalline polyester includes: a step (1) of fusing and polymerizing a source monomer to obtain a fused-polymerized material; a step (2) of pulverizing the fused and polymerized material to obtain a pulverized material having a weight average particle diameter of 1400 to 3300 μm; and a step (3) of subjecting the pulverized material to solid-phase polymerization to obtain a solid-phase polymerized material.

Description

  The present invention relates to a method for producing a liquid crystal polyester.

  As a method for producing a liquid crystal polyester, a method of subjecting a raw material monomer to melt polymerization, pulverizing the obtained melt polymer and then solid-phase polymerization has been studied. This method has an advantage that a high molecular weight liquid crystal polyester is easily obtained. For example, in Patent Document 1, the particle size of the pulverized product of the melt polymer to be solid-phase polymerized is preferably 0.05 to 3 mm, more preferably 0.05 to 1.5 mm, and still more preferably 0.1 to 1 mm. In particular, an example of 0.1 to 1 mm is shown. Patent Document 2 describes that the center particle diameter of a pulverized product of a melt polymer to be solid-phase polymerized is 50 to 1000 μm, preferably 100 to 600 μm, more preferably 200 to 500 μm. Specifically, examples of 256 μm, 478 μm, or 937 μm are shown, and a comparative example of 1216 μm is also shown.

JP 2005-272810 A JP 2012-201836 A

  In the conventional method, since the pulverized product is likely to be sintered (sintered or fused) during solid phase polymerization, it is difficult to remove the solid phase polymer from the solid phase polymerization vessel, or the solid phase polymer is pelletized or compounded. It may be difficult to handle during use. Accordingly, an object of the present invention is a method for producing a liquid crystal polyester by melt polymerizing a raw material monomer, pulverizing the obtained melt polymer, and then solid-phase polymerizing, and the pulverized product is obtained during solid-phase polymerization. The object is to provide a method that hardly causes sintering.

  In order to achieve the above object, the present invention includes a step (1) of melt polymerizing a raw material monomer to obtain a melt polymer, and grinding the melt polymer to give a weight average particle diameter of 1400 to 3300 μm. There is provided a method for producing a liquid crystalline polyester comprising a step (2) for obtaining a product and a step (3) for solid-phase polymerization of the pulverized product to obtain a solid-phase polymer.

  According to the present invention, the raw material monomer is melt-polymerized, and the resulting melt-polymerized product is pulverized and then solid-phase polymerized to suppress sintering of the pulverized product during solid-phase polymerization when producing liquid crystal polyester. can do. By suppressing this sintering, it is possible to increase the rate of temperature rise and temperature of solid phase polymerization, so that the time of solid phase polymerization can be shortened, and thus the productivity of liquid crystal polyester is increased. be able to.

  The liquid crystalline polyester is a polyester that exhibits liquid crystallinity in a molten state, and is, for example, at least one selected from the group consisting of aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, aromatic diols, aromatic hydroxyamines, and aromatic diamines. At least selected from the group consisting of polymerizing compounds (polycondensation), polymerizing a plurality of aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acids and aromatic diols, aromatic hydroxyamines and aromatic diamines. It can be produced by polymerizing one compound or polymerizing a polyester such as polyethylene terephthalate and an aromatic hydroxycarboxylic acid. Here, the aromatic hydroxycarboxylic acid, the aromatic dicarboxylic acid, the aromatic diol, the aromatic hydroxyamine, and the aromatic diamine are each independently replaced with a part or all of the polymerizable derivative. Also good.

  In the present invention, as a raw material monomer, at least one compound (1) selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof capable of polymerization (polycondensation), aromatic dicarboxylic acids and polymerization thereof (polycondensation) At least one compound (2) selected from the group consisting of possible derivatives and at least one selected from the group consisting of aromatic diols, aromatic hydroxyamines, aromatic diamines and derivatives capable of polymerization (polycondensation) thereof. The compound (3) is used, and these are polymerized to repeat a unit derived from an aromatic hydroxycarboxylic acid, a repeating unit derived from an aromatic dicarboxylic acid, an aromatic diol, an aromatic hydroxyamine, or an aromatic It is advantageously employed when producing a liquid crystalline polyester having a repeating unit derived from a diamine.

  Here, as an example of a polymerizable derivative of a compound having a carboxyl group such as an aromatic hydroxycarboxylic acid and an aromatic dicarboxylic acid, the carboxyl group is esterified (converted to an alkoxycarbonyl group or an aryloxycarbonyl group). (Esters), carboxyl groups halogenated (converted to haloformyl groups) (acid halides), and carboxyl groups acylated (converted to acyloxycarbonyl groups) (acid anhydrides) Can be mentioned. Examples of polymerizable derivatives of hydroxyl group-containing compounds such as aromatic hydroxycarboxylic acids, aromatic diols and aromatic hydroxyamines are those obtained by acylating hydroxyl groups (converting to acyloxyl groups) (acyls). Compound). Examples of polymerizable derivatives of compounds having an amino group such as aromatic hydroxyamine and aromatic diamine include those obtained by acylating (converting to an acylamino group) an amino group (acylated product).

  The compound (1) is preferably an aromatic hydroxycarboxylic acid and one obtained by acylating the hydroxyl group. As the compound (2), an aromatic dicarboxylic acid is preferable. Compounds (3) include aromatic diols, and those obtained by acylating at least one hydroxyl group thereof, aromatic hydroxyamines, and those obtained by acylating hydroxyl groups and / or amino groups thereof, and aromatic diamines. And those obtained by acylating at least one amino group thereof.

  In addition, as the compounds (1) to (3), compounds represented by the following formulas (1) to (3) are preferable, respectively.

Equation ^{(1): R 11 -O-} Ar 1 -CO-R 12

(Ar ¹ represents a phenylene group, a naphthylene group, or a biphenylylene group. R ¹¹ represents a hydrogen atom or an acyl group. R ¹² represents a hydroxyl group, an alkoxyl group, an aryloxyl group, an acyloxyl group, or a halogen atom. Each hydrogen atom in the group represented by Ar ¹ may be independently substituted with a halogen atom, an alkyl group, or an aryl group.

Equation ^{(2): R 21 -CO-} Ar 2 -CO-R 22

(Ar ² represents a phenylene group, a naphthylene group, a biphenylylene group or a group represented by the following formula (4). R ²¹ and R ²² are each independently a hydroxyl group, an alkoxyl group, an aryloxyl group, an acyloxyl. A hydrogen atom in the group represented by Ar ¹ may be independently substituted with a halogen atom, an alkyl group or an aryl group.

Equation ^{(3): R 31 -X-} Ar 3 -Y-R 32

(Ar ³ represents a phenylene group, a naphthylene group, a biphenylylene group or a group represented by the following formula (4). X and Y each independently represents an oxygen atom or an imino group (—NH—). ³¹ and R ³² each independently represents a hydrogen atom or an acyl group, and each hydrogen atom in the group represented by Ar ³ may be independently substituted with a halogen atom, an alkyl group or an aryl group. Good.)

Equation ^{(4): - Ar 41 -Z} -Ar 42 -

(Ar ⁴¹ and Ar ⁴² each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.)

Examples of the acyloxyl group represented by R ¹¹ , R ³¹ or R ³² include a formyl group, an acetyl group, a propionyl group and a benzoyl group, and the number of carbon atoms is usually 1-10. Examples of the alkoxyl group represented by R ¹² , R ²¹ or R ²² include methoxyl group, ethoxyl group, n-propyloxyl group, isopropyloxyl group, n-butyloxyl group, isobutyloxyl group, s-butyloxyl group. , T-butyloxyl group, n-hexyloxyl group, 2-ethylhexyloxyl group, n-octyloxyl group and n-decyloxyl group, and the number of carbon atoms is usually 1-10. Examples of aryloxy group represented by R ^12, R ²¹ or R ²² is phenyl oxyl group, o- Toriruokishiru group, m- Toriruokishiru group, p- Toriruokishiru group, 1-Nafuchiruokishiru group and 2- A naphthyloxyl group is mentioned, The carbon number is 6-20 normally. Examples of the acyloxyl group represented by R ¹² , R ²¹ or R ²² include a formyloxyl group, an acetyloxyl group, a propionyloxyl group, and a benzoyloxyl group, and the carbon number is usually 1 to 10. . Examples of the halogen atom represented by R ¹² , R ²¹ or R ²² include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

  Examples of the alkylidene group represented by Z include a methylene group, an ethylidene group, an isopropylidene group, an n-butylidene group and a 2-ethylhexylidene group, and the number of carbon atoms is usually 1 to 10.

Examples of the halogen atom that may replace the hydrogen atom in the group represented by Ar ¹ , Ar ^2, or Ar ³ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the alkyl group that may substitute a hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, An isobutyl group, s-butyl group, t-butyl group, n-hexyl group, 2-ethylhexyl group, n-octyl group and n-decyl group are mentioned, and the carbon number is usually 1-10. Examples of the aryl group that may substitute a hydrogen atom in the group represented by Ar ¹ , Ar ^2, or Ar ³ include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, 1 -A naphthyl group and 2-naphthyl group are mentioned, The carbon number is 6-20 normally. When the hydrogen atom in the group represented by Ar ¹ , Ar ^2, or Ar ³ is substituted with these groups, the number is as follows for each group represented by Ar ¹ , Ar ^2, or Ar ³ , Each of them is usually 2 or less, preferably 1 or less.

As compound (1), in formula (1), those in which Ar ¹ is a p-phenylene group and those in which Ar ¹ is a 2,6-naphthylene group are preferred. Further, as the compound (1), in the formula (1), those in which R ¹¹ and R ¹² are each a hydroxyl group, and those in which R ¹¹ is an acyl group and R ¹² is a hydroxyl group are preferable.

As compound (2), in formula (2), those in which Ar ² is a p-phenylene group, those in which Ar ² is an m-phenylene group, and those in which Ar ² is a 2,6-naphthylene group are preferred. . Further, as the compound (2), in the formula (2), those in which R ²¹ and R ²² are each a hydroxyl group are preferable.

As the compound (3), in the formula (3), those in which Ar ³ is a p-phenylene group and those in which Ar ³ is a 4,4′-biphenylylene group are preferable. Further, as the compound (3), in formula (3), those in which X and Y are each an oxygen atom, and those in which X is an oxygen atom and Y is an imino group are preferable. Further, as the compound (3), in the formula (3), R ³¹ and R ³² are each a hydrogen atom, R ³¹ is a hydrogen atom, R ³² is an acyl group, R ³¹ is an acyl group R ³² is preferably a hydrogen atom, and R ³¹ and R ³² are each preferably an acyl group.

  The amount of compound (1) used is usually 30 mol% or more, preferably 30 to 80 mol%, more preferably 40 to 70 mol%, still more preferably 45 to 65 mol%, based on the total amount of all raw material monomers. It is. The amount of the compound (2) used is usually 35 mol% or less, preferably 10 to 35 mol%, more preferably 15 to 30 mol%, still more preferably 17.5 to 27, based on the total amount of all raw material monomers. .5 mol%. The amount of compound (3) to be used is generally 35 mol% or less, preferably 10 to 35 mol%, more preferably 15 to 30 mol%, still more preferably 17.5 to 27, based on the total amount of all raw material monomers. .5 mol%. The more the compound (1) is used, the easier it is to improve the melt flowability, heat resistance and mechanical properties of the liquid crystal polyester. However, if the amount is too large, the melt temperature of the liquid crystal polyester tends to increase, and the temperature required for molding is high. It tends to be high and the solubility of the liquid crystalline polyester in the solvent tends to be low.

  The ratio between the amount of compound (2) used and the amount of compound (3) used is usually expressed as [amount of compound (2)] / [amount of compound (3)] (mol / mol). 0.9 / 1 to 1 / 0.9, preferably 0.95 / 1 to 1 / 0.95, and more preferably 0.98 / 1 to 1 / 0.98.

  In addition, two or more of the compounds (1) to (3) may be used independently. Moreover, although compounds other than compounds (1) to (3) may be used as the raw material monomer, the amount used is usually 10 mol% or less, preferably 5 mol%, based on the total amount of all raw material monomers. It is as follows.

  The raw material monomer as described above is melt polymerized to obtain a melt polymer (step (1)). As the melt polymerization container, a container having an outlet at the bottom is preferably used so that the melt polymer can be taken out from the melt polymerization container in a molten state after the melt polymerization.

  Melt polymerization may be carried out in the presence of a catalyst. Examples of this catalyst include metal compounds such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide, And nitrogen-containing heterocyclic compounds such as 4- (dimethylamino) pyridine and 1-methylimidazole, and nitrogen-containing heterocyclic compounds are preferably used.

  The melt polymerization is preferably performed until the flow start temperature of the resulting melt polymer is 150 to 320 ° C, and more preferably 200 to 300 ° C. If the flow start temperature of the melt polymer is too high, it will be difficult to extract the melt polymer by extracting it from the melt polymerization vessel in the molten state. The degree of polymerization of the resulting solid phase polymer tends to be insufficient, and its heat resistance and mechanical properties tend to be insufficient.

The flow start temperature is also called flow temperature or flow temperature, and the temperature is raised at a rate of 4 ° C./min under a load of 9.8 MPa (100 kg / cm ² ) using a capillary rheometer while the liquid crystalline polyester is used. Is a temperature showing a viscosity of 4800 Pa · s (48000 poise) when extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm, and is a measure of the molecular weight of the liquid crystalline polyester (Naide Koide, “ “Liquid Crystal Polymer—Synthesis / Molding / Application—”, CMC Co., Ltd., June 5, 1987, p. 95).

  The molten polymer thus obtained is pulverized to obtain a pulverized product (powder) (step (2)). The pulverization of the molten polymer is preferably carried out by extracting the molten polymer from the melt polymerization vessel in a molten state, solidifying by cooling, and pulverizing the obtained solid.

  In the present invention, the molten polymer is pulverized so that the pulverized product obtained has a weight average particle diameter of 1400 μm or more. Thereby, sintering of the pulverized product in the subsequent solid phase polymerization step can be suppressed. By suppressing this sintering, it is possible to increase the rate of temperature rise and temperature of solid phase polymerization, so that the time of solid phase polymerization can be shortened, and thus the productivity of liquid crystal polyester is increased. be able to. However, if the weight average particle size of the pulverized product is too large, solid phase polymerization is difficult to proceed. Therefore, the weight average particle size of the pulverized product is set to 3300 μm or less. The weight average particle diameter of the pulverized product is preferably 1700 to 2500 μm.

  The weight average particle diameter of the pulverized product is measured by a screening test method of JIS Z8815: 1994.

  Examples of the pulverizer include a joke crusher, a gyle crusher, a cone crusher, a roll crusher, an impact crusher, a hammer crusher, a cutter mill, a rod mill, a ball mill, and a jet mill.

  The obtained pulverized product is subjected to solid phase polymerization to obtain a solid phase polymerized product (step (3)). Thereby, high molecular weight liquid crystal polyester excellent in heat resistance and mechanical properties can be obtained as a powdery solid phase polymer while suppressing sintering of the pulverized product. As the solid phase polymerization vessel, a tray made of metal such as stainless steel (SUS) is preferably used.

  The solid phase polymerization is preferably carried out until the flow initiation temperature of the obtained solid phase polymerized product reaches 200 to 420 ° C., more preferably 240 to 400 ° C. If the flow initiation temperature of the solid phase polymer is too high, the melting temperature tends to be high, the temperature required for molding tends to be high, and the solubility in the solvent tends to be low. If it is too low, the heat resistance and mechanical properties are low. Characteristics tend to be insufficient.

  After the solid phase polymerization, the solid phase polymerization product is taken out from the solid phase polymerization vessel, and the solid phase polymerization product is recovered as a liquid crystal polyester of the product. The liquid crystal polyester thus obtained can be used as a molding material for producing various products such as electric and electronic parts by blending fillers and additives therein if necessary.

[Measurement of flow start temperature]
Using a flow tester (“CFT-500 type” manufactured by Shimadzu Corporation), about 2 g of the sample was filled into a cylinder equipped with a die having a nozzle having an inner diameter of 1 mm and a length of 10 mm, and 9.8 MPa (100 kg / The sample was melted while being heated at a rate of 4 ° C./min under a load of cm ² ), extruded from a nozzle, and a temperature showing a viscosity of 4800 Pa · s (48000 poise) was measured.

(Measurement of weight average particle diameter)
It measured by the screening test method of JISZ8815: 1994.

Examples 1-3 and Comparative Examples 1-3
In a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer and reflux condenser, p-hydroxybenzoic acid 60 mol%, terephthalic acid 15 mol%, isophthalic acid 5 mol%, and 4 , 4′-dihydroxybiphenyl is added in a proportion of 20 mol%, and acetic anhydride is added in an amount of 1.1 mol based on the total amount of p-hydroxybenzoic acid, terephthalic acid, isophthalic acid and 4,4′-dihydroxybiphenyl. The acetic acid solution of 1-methylimidazole is doubled, and the amount of 1-methylimidazole becomes 100 mass ppm with respect to the total amount of p-hydroxybenzoic acid, terephthalic acid, isophthalic acid and 4,4′-dihydroxybiphenyl. The mixture was heated from room temperature to 145 ° C. over 1 hour with stirring under a nitrogen gas stream and refluxed at 145 ° C. for 30 minutes. Next, in the acetic acid solution of 1-methylimidazole, the amount of 1-methylimidazole is 500 ppm by mass with respect to the total amount of p-hydroxybenzoic acid, terephthalic acid, isophthalic acid, and 4,4′-dihydroxybiphenyl. In addition, while the by-product acetic acid and unreacted acetic anhydride were distilled off, the temperature was raised from 145 ° C. to 300 ° C. over 2 hours and 35 minutes, and then the contents were taken out of the reactor and cooled to room temperature.

  The obtained solid (melt polymer) was roughly crushed, and then pulverized (Orient grinder, model: VM-16) and screen (hole diameter: 2 mm (Comparative Example 1), 3 mm (Comparative). Example 2) 4 mm (Comparative Example 3), 5 mm (Example 1), 6 mm (Example 2), or 8 mm (Example 3)), and powder having a weight average particle diameter shown in Table 1 -Shaped prepolymer (melt polymerized product) was obtained. The flow initiation temperature of this prepolymer was 260 ° C.

  The obtained prepolymer was heated from room temperature to 230 ° C. over 1 hour in a nitrogen gas atmosphere, heated from 230 ° C. to 240 ° C. over 10 minutes, and then heated from 240 ° C. to 310 ° C. over 5 hours 59 minutes. The mixture was heated and held at 310 ° C. for 1 hour and 30 minutes to cause solid phase polymerization (8 hours and 39 minutes in total) and then cooled to obtain a powdery liquid crystalline polyester (solid phase polymer). The flow start temperature of this liquid crystal polyester is shown in Table 1. Further, the degree of sintering of the liquid crystal polyester was visually observed. ○: “No sintering”, Δ: “Sintering is weak but can be easily broken.”, X: “Sinter It has a ring and is strong, so it is difficult to break. "

Comparative Example 4
The same operations as in Examples 1 to 3 and Comparative Examples 1 to 3 were performed, except that the solid (melt polymer) was coarsely ground and then solid-phase polymerized without being finely ground. The results are shown in Table 1.

Reference example 1
Prepolymer (melt polymerized product) was heated from room temperature to 230 ° C over 1 hour in a nitrogen gas atmosphere, heated from 230 ° C to 240 ° C over 10 minutes, and from 240 ° C to 290 ° C. The temperature was increased over 6 hours and 25 minutes, and the same operation as in Comparative Example 1 was performed except that solid phase polymerization was performed by maintaining at 290 ° C. for 5 hours (total 12 hours and 35 minutes). The results are shown in Table 1.

Claims (3)

  A step (1) of melt-polymerizing the raw material monomers to obtain a melt polymer, a step (2) of obtaining a pulverized product having a weight average particle diameter of 1400 to 3300 μm by pulverizing the melt polymer, and the pulverization And a step (3) of obtaining a solid-phase polymer by solid-phase polymerization of the product.   The raw material monomer is at least one compound (1) selected from the group consisting of an aromatic hydroxycarboxylic acid and a polymerizable derivative thereof, and at least one selected from the group consisting of an aromatic dicarboxylic acid and a polymerizable derivative thereof. 2. A monomer comprising at least one compound (2) and at least one compound (3) selected from the group consisting of aromatic diols, aromatic hydroxyamines, aromatic diamines and polymerizable derivatives thereof. The manufacturing method of liquid crystalline polyester as described in 2. The compound (1) is a compound represented by the following formula (1), the compound (2) is a compound represented by the following formula (2), and the compound (3) is represented by the following formula (3). The method for producing a liquid crystal polyester according to claim 2, wherein the compound is a compound represented.
Equation ^{(1): R 11 -O-} Ar 1 -CO-R 12
(Ar ¹ represents a phenylene group, a naphthylene group, or a biphenylylene group. R ¹¹ represents a hydrogen atom or an acyl group. R ¹² represents a hydroxyl group, an alkoxyl group, an aryloxyl group, an acyloxyl group, or a halogen atom. Each hydrogen atom in the group represented by Ar ¹ may be independently substituted with a halogen atom, an alkyl group, or an aryl group.
Equation ^{(2): R 21 -CO-} Ar 2 -CO-R 22
(Ar ² represents a phenylene group, a naphthylene group, a biphenylylene group or a group represented by the following formula (4). R ²¹ and R ²² are each independently a hydroxyl group, an alkoxyl group, an aryloxyl group, an acyloxyl. A hydrogen atom in the group represented by Ar ¹ may be independently substituted with a halogen atom, an alkyl group or an aryl group.
Equation ^{(3): R 31 -X-} Ar 3 -Y-R 32
(Ar ³ represents a phenylene group, a naphthylene group, a biphenylylene group or a group represented by the following formula (4). X and Y each independently represent an oxygen atom or an imino group. R ³¹ and R ³² represent Each independently represents a hydrogen atom or an acyl group, and each hydrogen atom in the group represented by Ar ³ may be independently substituted with a halogen atom, an alkyl group or an aryl group.
Equation ^{(4): - Ar 41 -Z} -Ar 42 -
(Ar ⁴¹ and Ar ⁴² each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.)