KR910005770B1 - Polyethylene telephthalate copolymers and preparation for the copolymers - Google Patents

Abstract

The polyethylene terephthalate copolymer comprises the repeating units of formula (I), (II) and (III)). The repeating unit (I) is 3-60 mole.% w.r.t. total repeating units, and the (II) and (III) of the rest repeating units are equivalant mole. In the formula, n is 0 or 1. This process is prevent to forming p-acetoxy benzoic acid block which is formed self condensation reacting of p- acetoxy benzoic acid, and the obtd. PET copolymer has a good spinnability.

Description

Polyethylene terephthalate copolymer and preparation method thereof

1 is a graph showing the comparison of the melt viscosity measured by the capillary rheometer with respect to the polyethylene terephthalate copolymer prepared according to the method of the present invention and the polyethylene terephthalate copolymer prepared by the conventional method.

The present invention relates to a polyethylene terephthalate copolymer and a preparation method thereof, and more particularly, to a repeating unit represented by the following structural formula (I), a repeating unit represented by the following structural formula (II) and the following structural formula (III) It relates to a polyethylene terephthalate copolymer having a repeating unit at the same time and a method for producing the same.

(Where n is 0 or 1)

In recent years, polyethylene terephthalate (hereinafter referred to as PET) has been actively researched to manufacture PET copolymers having more excellent physical properties as the field of use of films, filaments, taorecoins, ropes, etc. has been greatly expanded. Among them, U.S. Patent Nos. 3,890,256 and 3,778,410, 3,804,805 and the like show that PET is added to 40 to 90 mol% of p-acetoxybenzoic acid and terephthalic acid to produce copolyester, thereby showing optical anisotropy during melting. Techniques for copolyesters with excellent mechanical properties have been introduced.

However, in the above technique, p-acetoxybenzoic acid is added to the polymerization chain of PET to decompose the PET chain and cause a self-condensation reaction. The p-acetoxybenzoic acid block thus formed is insoluble even at low molecular weight. In addition, since the fluidity of the final polymer is lowered, there is a critical disadvantage of greatly reducing the spinnabilty of the prepared copolymer.

In order to solve this drawback, US Pat. No. 4,075,262 uses transesterification reaction using PET, aromatic dicarboxylic acid and aromatic diol containing the following structure (A) instead of using p-acetoxybenzoic acid. Although a method of preparing a copolyester has been described, in this method, the mechanical properties of PET are improved, but the production cost increases with the use of an aromatic diol having a substituent, and in particular, the physical properties of the prepared copolymer are poor. There was a problem.

(Wherein X is -Cl, -CH ₃ and the number of substituents is one or two.)

Accordingly, the present invention provides a self-condensation of p-acetoxybenzoic acid during the preparation process by adding p-acetoxybenzoic acid to the PET chain using aromatic diol derived from p-acetoxybenzoic acid in preparing the PET copolymer. The purpose of the present invention is to provide a method of preventing the formation of p-acetoxybenzoic acid block by the reaction and to produce a PET copolymer having improved radioactive properties such as radioactivity at low cost and a PET copolymer prepared therefrom. .

Hereinafter, the present invention will be described in detail.

The present invention in the PET copolymer, having the repeating units represented by the following structural formula (I), (II), (III) at the same time, the repeating unit represented by the structural formula (I) is 3 to 60 of the total repeating unit Molar%, and the remaining repeating units of the formulas (II) and (III) are PET copolymers present in equimolar amounts to each other.

(Where n is 0, 1)

In addition, the present invention in the manufacture of PET copolymer, 3 to 60 mol% polyethylene terephthalate derivative including the structural formula (I), and 20 to 48.5 mol% p-acetoxybenzoic acid derivative including the structural formula (II) And 20 to 48.5 mol% of aromatic dicarboxylic acid containing the structural formula (III) is first reacted by heating to a temperature of 250 ℃ to 350 ℃ under a nitrogen atmosphere, and then the pressure of 0.1 to 20mmHg and 300 to 340 ℃ It is a manufacturing method of the polyethylene terephthalate copolymer characterized by performing secondary reaction at temperature.

Hereinafter, the present invention will be described in more detail.

PET copolymer according to the present invention is a total of three monomers, that is, PET containing the structural formula (I), aromatic diol containing the structural formula (II), and aromatic containing the structural formula (III) It consists of dicarboxylic acid. First, the PET containing the structural formula (I) has been used conventionally, the PET copolymer according to the present invention is 3 to 60 mol% of the repeating units of the structural formula (I), preferably 5 to 50 It is good to include as much as mole%.

In addition, the aromatic diol containing the structural formula (II) is derived from p-acetoxybenzoic acid, for example 4'-acetoxyphenyl-4-acetoxybenzoate, 3-acetoxyphenyl-4-acet Derived from any one of oxybenzoate, 1,3-bis (4-acetoxy benzoyloxy) benzene, 1,4-bis (4-acetoxy benzoyloxy) benzene, or mixtures thereof. The aromatic dicarboxylic acid containing) has a para compound or meta compound.

At this time, the structural unit (II) and the repeating units of the structural formula (III) are present in equimolar amounts.

On the other hand, in order to produce a PET copolymer according to the present invention can be used a conventionally well-known melt polymerization method, for example, PET containing the structural formula (I) having an intrinsic viscosity (ηinh) of 0.2 or more, the structural formula ( It is polymerized with p-acetoxybenzoic acid derivative containing II) and aromatic dicarboxylic acid containing the same amount of structural formula (III). At this time, PET is 3 to 150 mol% based on the sum of the p-acetoxybenzoic acid derivative and aromatic dicarboxylic acid, that is, 3 to 60 mol% with respect to the whole, and p-acetoxybenzoic acid derivative and aromatic dicar The main acid is used to be 20 to 48.5 mol% of the total, respectively. If bis- (β-hydroxyethyl) benzoate is used as the p-acetoxybenzoic acid derivative, 5 to 12 mol% of PET is used. It is preferable.

In the present invention, the aromatic dicarboxylic acid containing the structural formula (III) is terephthalic acid or isophthalic acid.

In this manner, after mixing the three monomers, i.e., each compound containing the structural formula (I), the structural formula (II), and the structural formula (III), they are mixed to a temperature of 250 to 300 DEG C under anhydrous atmosphere such as nitrogen or argon. The mixture was first reacted with acetic acid as the byproduct was not stirred while raising the temperature by stirring, and in order to obtain a polymer having a higher molecular weight, a second reaction was carried out at a temperature of 300 to 340 ° C under a pressure of 0.1 to 20 mmHg to obtain a polymer having a desired molecular weight. There is a number.

The PET copolymer prepared in this way is used for fiber spinning and injection molding, and in particular, when it is spun into fibers, the orientation is very excellent, and even when the film is produced, it has a very good material.

When spinning the PET copolymer of the present invention, it was pulverized with a wiley mill, dried for 8 hours at a temperature of 120 ° C. in a vacuum dryer, and then put into a cylindrical tube having a diameter of 3 cm and a length of 20 cm. 10 holes of 0.17mn are used as nozzles and spun in a molten state at a nitrogen pressure of 45kg / Cm ₂ .

Hereinafter, a preparation example of the p-acetoxybenzoic acid derivative including the structural formula (II), which is one of the monomers according to the present invention, and an implementation for producing the polyethylene terephthalate according to the present invention using this as one of the monomers. An example will be described as follows.

[Production Example 1]

Preparation of 4'-acetoxyphenyl-4-acetoxybenzoate

1 mole of p-acetoxybenzoic acid and 1 to 4 moles of hydroxyquinone diacetate are placed in a flask equipped with a stirrer, nitrogen, a thermometer and a condenser, and heated to collect acetic acid as a by-product from around 190 ° C. Precipitate the crystals.

3 to 5 times washing to remove the unreacted substances, and a concentration of 1 to 2N of NaOH aqueous solution, or NaHCO ₃ aqueous solution, or NaHCO After the _aqueous solution by washing twice or three times, again washed with water and recrystallized (melting point: 160 ~ 162 ° C, yield: 90%), the product was confirmed to have the following structure by the IR, NMR analysis.

[Production Example 2]

Preparation of 3-acetoxyphenyl-4-acetoxyphenylbenzoate

1 mole of p-acetoxybenzoic acid is refluxed for 6 hours using 2 to 10 molar excess of thionyl chloride to obtain p-acetoxybenzoic acid chloride.

Subsequently, 0.8 to 2.0 moles of resorcinol was dissolved in an excess of pyridine, and the p-acetoxybenzoic acid chloride was slowly added thereto to react at room temperature, and then the product was thus confirmed for its structure.

[Manufacture example 3]

Preparation of 1,3-bis (4-acetoxy benzoyloxy) benzene

2-3 mol of p-acetoxybenzoic acid chloride is added to 1 mol of resorcinol-pyridine solution and reacted at room temperature.

Crystals were precipitated with methanol and recrystallized to confirm the structure. (Melting point: 118 to 120 DEG C, yield: 90%).

[Production Example 4]

Synthesis of 1,4-bis (4-acetoxy benzoyloxy) benzene

2-3 mol of p-acetoxybenzoic acid chloride is added to 1 mol of hydroquinone-pyridine solution to react at room temperature, and crystals are precipitated with methanol to recrystallize (melting point: 185 to 186 DEG C, yield: 90%). )

According to IR and NMR analysis results, the following structural formula is provided.

Example 1

57.6 g (0.3 mol) of polyethylene terephthalate (ηinh = 0.6, 2 mm size), 94.2 g (0.3 mol) of 4′-acetoxyphenyl-4-acetoxybenzoate, and 49.8 g (0.3 mol) of terephthalic acid were added to the reaction tube. Input, and then nitrogen.

Subsequently, the mixture was kept at 110 ° C. for 15 minutes to remove moisture, and the temperature was raised to 275 ° C. to release acetic acid under stirring. Then, the temperature was gradually increased while applying a vacuum, and acetic acid was allowed to flow out under stirring. , And reacted under 2 mmHg pressure for 3 hours to obtain a PET copolymer. The obtained polymer had an ηinh of 0.78 and a melting point of 270 ° C. It was spun at 280 ° C. so that the fiber was T / E / Mi = 4.1 / 2.4 / 280. Where T is the tensile strength in g / d, E is the elongation at break in%, and Mi is the initial modulus in g / d.

Example 2

19.2 g (0.1 mol) of polyethylene terephthalate (ηinh = 0.6, 2 mm size), 130.2 g (0.3 mol) of 1,4bis (4-acetoxybenzoyloxy) benzene, and 49.8 g (0.3 mol) of isophthalic acid in Example 1 mol) was used to obtain a PET copolymer having an ηinh of 0.8. The melting point was 368 ° C., and the fiber obtained by spinning at 280 ° C. had a T / E / Mi of 4.8 / 3.5 / 270.

After heat treatment at 250 ° C. for 24 hours, T / E / Mi increased to 8.2 / 3.8 / 280.

Example 3

In Example 1, 9.6 g (0.05 mol) of polyethylene terephthalate (ηinh = 0.54, 2 mm size), 130.2 g (0.3 mol) of 1,3-bis (4-acetoxy benzoyloxy) benzene, and 49.8 g of terephthalic acid ( 0.3 mol) was used to obtain a PET copolymer having an ηinh of 0.94. The melting point was 246 ° C, and the fiber obtained by spinning at 260 ° C had a T / E / Mi of 2.9 / 8.2 / 240, which was then heat-treated at 240 ° C for 30 hours, and the T / E / Mi was 5.8 / 8.4 / 260. Increased.

Example 4

In Example 1, 38.4 g (0.2 mol) of polyethylene terephthalate (ηinh = 0.54, 2 mm size), 94.2 g (0.3 mol) of 4′-acetoxyphenylbenzoate, and 49.8 g (0.3 mol) of isophthalic acid were used. To obtain a PET copolymer having a? Inh of 0.9. The melting point of the obtained PET copolymer was 258 ° C., and the fiber obtained by spinning at 280 ° C. had a T / E / Mi of 3.9 / 3.0 / 270, which was heat-treated at 230 ° C. for 40 hours, and the T / E / Mi was 10.4 /. It was increased to 3.3 / 270.

Example 5

In Example 1 57.6 g (0.3 mol) of polyethylene terephthalate (ηinh = 0.8, 2 mm size), 130.2 g (0.3 mol) of 1,4-bis (4-acetoxy benzoyloxy) benzene, and 49.8 g (0.3 mol) of terephthalic acid mol) was used to obtain a polymer having an ηinh of 0.96. The melting point was 283 ℃ and the fiber obtained by spinning at 300 ℃ had T / E / Mi of 5.0 / 1.8 / 290, and after 24 hours of heat treatment at 265 ℃, the T / E / Mi increased to 11.2 / 3.0 / 295.

Example 6

149.5 g (0.1 mol) of bis (β-hydroxyethyl) terephthalate, 149.5 g (0.9 mol) of terephthalic acid and 0.01 g of antimony trioxide were added to the reaction tube and reacted under nitrogen stream at 280 ° C., followed by vacuum of 1 mmHg. React for 3 minutes on foot.

After cooling the reaction tube, 251.2 g (0.8 mol) of 4'-acetoxyphenyl-4-ethoxybenzoate was added thereto, and the PET copolymer having ηinh of 1.2 was obtained as in Example 1 at 320 ° C. The melting point was 309 ° C., which was spun at 330 ° C. to obtain a fiber with T / E / Mi = 5.2 / 3.1 / 302. After heat treatment at 270 ° C. for 16 hours, T / E / Mi increased to 12.2 / 3.3 / 310.

Comparative Example 1

In Example 1, 57.6 g (0.3 mol) of polyethylene terephthalate (ηinh = 0.54, 2 mm size), 58.2 g (0.3 mol) of hydroquinone diacedate, 54 g (0.3 mol) of p-acetoxybenzoic acid, 49.8 g of terephthalic acid ( 0.3 mol) was used to obtain a polymer having? Inh of 0.72. The fiber obtained by spinning it at 280 ° C. had a T / E / Mi of 3.8 / 2.1 / 275.

Comparative Example 2

In Example 3, polyethylene terephthalate (ηinh = 0.54, 2 mm size) 9.6 g (0.05 mol), resorcinol diacetate 58.2 g (0.3 mol), p-acetoxybenzoic acid 108 g (0.6 mol), terephthalic acid 49.8 g (0.3 mol) ) Was used to obtain a polymer having an ηinh of 0.96. This was spun at 240 ° C. to obtain a fiber having a T / E / Mi of 2.5 / 6.2 / 240. After heat treatment at 240 ° C. for 30 hours, T / E / Mi increased to 5.6 / 8.4 / 250.

In order to analyze the PET copolymers prepared according to the above examples and comparative examples, the melting point thereof was measured using DSC-II, and these are shown in FIG. At this time, the heating rate was measured at 20 ℃ / min.

Intrinsic viscosity (η inh) was measured at 30 ° C. with a Eubrodometer using a solvent in which trifluoroacetic acid and methyl chloride were mixed in a volume ratio of 60/40, and ηinh was obtained from the following equation.

The relative viscosity (ηrel) is a value obtained by dividing the drop time of the solution by the drop time of the pure solvent, and the solution viscosity (C) was 0.5 g / s. In addition, the flowability of the polymer was determined by melt viscosity measured using a capillary rheometer, and optical anisotropy was observed by a polarizing microscope attached to a heating plate.

Claims (10)

Polyethylene terephthalate copolymer, which has a repeating unit represented by the following structural formula (I), (II), (III), wherein the repeating unit represented by the structural formula (I) is 3 to 60 mol% of the total repeating unit And the remaining repeating units of the formulas (II) and (III) are present in equimolar amounts to each other, polyethylene terephthalate copolymer.

(Where n is 0.1) The method of claim 1, wherein the repeating unit represented by the formula (II) is 4'-acetoxyphenyl-4-acetoxy benzoate, 3-acetoxyphenyl-4-acetoxy benzoate, 1,3-bis ( Polyethylene terephthalate copolymer, characterized in that it is derived from any one of 4-acetoxy benzoyloxy) benzene, 1,4-bis (4-acetoxy benzoyloxy) benzene, or mixtures thereof. The polyethylene terephthalate copolymer according to claim 1, wherein the repeating unit represented by the structural formula (III) is a meta compound. The polyethylene terephthalate copolymer according to claim 1, wherein the repeating unit represented by the structural formula (III) is a para compound. In preparing the polyethylene terephthalate copolymer, 3 to 60 mol% of polyethylene terephthalate derivative including the structural formula (I), 20 to 48.5 mol% of p-acetoxybenzoic acid derivative including the structure (II), and 20 to 48.5 mol% of the aromatic dicarboxylic acid including the structural formula (III) was first reacted by heating to a temperature of 250 ° C to 350 ° C under a nitrogen atmosphere, followed by a pressure of 0.1 to 20mmHg and a temperature of 300 to 340 ° C. Method for producing a polyethylene terephthalate copolymer, characterized in that the secondary pressure. The p-acetoxybenzoic acid derivative according to claim 5, wherein the p-acetoxybenzoic acid derivative is 4'-acetoxy phenyl-4-acetoxy benzoate, 3-acetoxy phenyl-4-acetoxy benzoate, 1,3-bis (4-acetoxy Benzoyloxy) benzene, 1,4-bis (4-acetoxy benzoyloxy) benzene, or a mixture thereof. 6. The process of claim 5 wherein the aromatic dicarboxylic acid uses terephthalic acid. The method of claim 5 wherein the aromatic dicarboxylic acid uses isophthalic acid. The structural formula (I), (II), (III) having a repeating unit represented by these, the repeating unit represented by the structural formula (I) is 3 to 60 mol% of the total repeating unit, the remaining structural formula ( Repeating units of II) and (III) are fibers produced using polyethylene terephthalate copolymers present in equimolar amounts with each other. It has a repeating unit represented by the structural formula (I), (II), (III), the repeating unit represented by the structural formula (I) is 3 to 60 mol% of the total repeating unit, the remaining structural formula (II) The repeating unit of (III) and (III) film produced using a polyethylene terephthalate copolymer present in an equimolar amount to each other.

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