JPH06293825A - Production of polyethylene naphthalate - Google Patents

Abstract

PURPOSE:To obtain the subject compound useful for film, etc., having excellent surface flatness by reacting a naphthalenedicarboxylic acid alkyl ester with ethylene glycol in the presence of a specific amount of a specific compound as a catalyst. CONSTITUTION:The objective compound is produced by the transesterification reaction of a lower alkyl ester (especially preferably dimethyl ester) of a naphthalenedicarboxylic acid (especially preferably 2,6-naphthalenedicarboxylic acid) with ethylene glycol in the presence of a catalyst consisting of a manganese compound, a potassium compound, a phosphorus compound and an antimony compound added to the system at ratios satisfying the formula I to formula IV (Mn is molar number of the manganese compound per 10<6>g of the acid component; K is molar number of the potassium compound per 10<6>g of the acid component; P is molar number of the phosphorus compound per 10<6>g of the acid component; Sb is molar number of the antimony compound per 10<6>g of the acid component).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing polyethylene naphthalate, and more particularly to a method for producing polyethylene naphthalate for forming a product having excellent surface flatness and a special film.

[0002]

2. Description of the Related Art Polyethylene naphthalate film is
Since it is excellent in basic physical properties such as heat resistance and strength as compared with polyethylene terephthalate film, its use in various applications such as magnetic recording media, capacitors, and electrical tapes has been studied and many proposals have been made.

However, particularly when used as a base film of a magnetic recording medium, a flat surface property is required, but the conventional polyethylene naphthalate film is not particularly one which can sufficiently achieve the surface flatness required for the base film of vapor deposition video tape. There wasn't. It is considered that this is because the component used as a catalyst is deposited or a compound is formed with a polymer component to form fine irregularities on the film surface.

Conventionally, various optimizations of the catalyst addition amount and the addition method have been studied in order to secure the surface flatness of such a film, but this has been sufficiently investigated for polyethylene naphthalate. The actual situation is that satisfactory results have not been obtained.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present inventors have made earnest studies as a result of developing a molded article excellent in surface flatness, particularly a polyethylene naphthalate capable of forming a film. If polyethylene naphthalate produced by a method of adding a compound, a potassium compound, a phosphorus compound, an antimony compound as a catalyst in a specific amount at a specific ratio is used, a polyethylene naphthalate molded product having excellent surface flatness, particularly a film can be obtained. The present invention has been achieved by finding that the above can be achieved.

Therefore, an object of the present invention is to provide a method for producing a molded article excellent in surface flatness, particularly a polyethylene naphthalate capable of forming a film.

[0007]

The object of the present invention is, according to the present invention, to produce a polyethylene naphthalate by reacting a lower alkyl ester of naphthalenedicarboxylic acid with ethylene glycol, a manganese compound, a potassium compound, This is achieved by a method for producing polyethylene naphthalate, which comprises adding a phosphorus compound and an antimony compound in a ratio that satisfies the following formulas (1) to (4).

[0008]

[Equation 2]

(Mn is the number of moles of the manganese compound per 10 ⁶ g of the acid component, K is the number of moles of the potassium compound per 10 ⁶ g of the acid component, P is the phosphorus compound, the acid component 1
0 per ⁶ moles, Sb is antimony compound, is the molar number per acid component 10 ⁶ g. )

Examples of the naphthalenedicarboxylic acid in the present invention include 2,6-naphthalenedicarboxylic acid, 2,
Examples thereof include 7-naphthalenedicarboxylic acid and 1,5-naphthalenedicarboxylic acid, with 2,6-naphthalenedicarboxylic acid being particularly preferred.

Preferred examples of the lower alkyl ester of naphthalene dicarboxylic acid include dimethyl ester, diethyl ester and dipropyl ester, and dimethyl ester is particularly preferred.

In the present invention, a lower alkyl ester of naphthalenedicarboxylic acid is reacted with ethylene glycol to obtain polyethylene naphthalate. In this reaction, a part of the lower alkyl ester of naphthalenedicarboxylic acid (for example, 20 mol% or less) is used. May be replaced by other acid components, and a part of ethylene glycol (eg 20
(Mol% or less) may be replaced with another glycol component.

Other acid components include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, diphenylethanedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylketonedicarboxylic acid and anthracenedicarboxylic acid. Aliphatic dicarboxylic acids such as adipic acid,
Examples include sebacic acid and the like; alicyclic dicarboxylic acids such as cyclohexane-1,4-dicarboxylic acid and the like.

Other glycol components include aliphatic glycols such as trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, and other polymethylene glycols having 3 to 10 carbon atoms, cyclohexanedimethanol, and the like. Aromatic diols such as hydroquinone,
Resorcin, 2,2-bis (4-hydroxyphenyl)
Propane, etc .; Aliphatic diols having aromatic rings, eg 1,
4-dihydroxymethylbenzene and the like; polyalkylene glycol (polyoxyalkylene glycol) such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like can be exemplified.

Further, in the present invention, a component derived from an oxycarboxylic acid such as an aromatic oxyacid such as hydroxybenzoic acid; an aliphatic oxyacid such as ω-hydroxycaproic acid is used as a dicarboxylic acid component and an oxycarboxylic acid. It is also possible to copolymerize or combine with 20 mol% or less based on the total amount of the components.

Further, in the present invention, the amount of polyethylene naphthalate obtained is in the range of being substantially linear,
For example, trifunctional or higher polycarboxylic acids or polyhydroxy compounds such as trimellitic acid and pentaerythritol can be copolymerized in an amount of 2 mol% or less based on the total acid components.

In the present invention, the lower alkyl ester of naphthalenedicarboxylic acid is reacted with ethylene glycol by adding 0.4 to 4.0 mol of a manganese compound soluble in the reaction system to the acid component. Then, a transesterification reaction is carried out (hereinafter, mole means the number of moles per 10 ⁶ g of the acid component).

When the amount of the manganese compound added to the acid component as the transesterification catalyst exceeds 4.0 moles, the surface flatness of the film when formed into a film is deteriorated due to the influence of precipitated particles due to the catalyst residue, while If it is less than 4 mol, the transesterification reaction will not be completed.

The ratio (molar ratio) of the potassium compound to the manganese compound is preferably 0.01 to 0.25. The range of 0.05 to 0.2 is particularly preferable.
If this molar ratio exceeds 0.25 or less than 0.01,
Due to the influence of the catalyst residue, the surface flatness when formed into a film deteriorates.

Then, when the transesterification reaction is substantially completed, a phosphorus compound is added to inactivate a part of the transesterification reaction catalyst. The transesterification catalyst, that is, the manganese compound, is added with respect to the amount of the phosphorus compound added. And the molar ratio of the total amount of one half of the potassium compound is
0.1 to 0.8 is preferable. If the molar ratio is larger than 0.8 or smaller than 0.1, the film flatness is deteriorated.

Thereafter, the reaction product is subjected to a polycondensation reaction to form a polymer, and an antimony compound is added to the reaction product as a main catalyst of this polycondensation reaction. The amount is
0.2-1.45 mol is preferable. If this amount exceeds 1.45 mol, when the film is formed for a long time,
Precipitates due to antimony compounds are film defects, while if less than 0.2 mol, polycondensation reaction is poor,
Productivity is poor and it is substantially undesirable.

The manganese compound and the potassium compound used in the present invention are not particularly limited, but oxides, chlorides, carbonates, carboxylates and the like are preferable, and acetates, that is, manganese acetate and potassium acetate are particularly preferable. .

The phosphorus compound is not particularly limited, but trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate and the like are preferable, and trimethyl phosphate is particularly preferable.

Further, the antimony compound is not particularly limited, but antimony acetate, antimony trioxide and the like are preferable, and antimony trioxide is particularly preferable.

In the present invention, in the production of polyethylene naphthalate, for example, pigments, dyes, ultraviolet absorbers,
Additives such as heat stabilizers, light stabilizers, antioxidants, light-shielding agents (for example, carbon black, titanium dioxide, etc.) can be added as necessary.

The polyethylene naphthalate obtained in the present invention has no or extremely small amount of polymer insoluble matter due to the catalyst, and is particularly useful as a raw material for film forming.

As a means for molding this polyethylene naphthalate into a film, a known method can be used. For example, dried polyethylene naphthalate is melt-extruded into a sheet at a temperature of melting point (° C) to (melting point +65) ° C and rapidly solidified to obtain an unstretched film (sheet). Then, the unstretched film is stretched in the machine direction, and then stretched in the transverse direction, that is, a so-called longitudinal and transverse sequential biaxial stretching method, or a method in which the order is reversed to perform stretching. The stretching temperature, the stretching ratio and the like can be selected from known conditions.

[0028]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples as long as the gist thereof is not exceeded.

In the examples, "part" means part by weight. Further, the measurement of each characteristic value in the examples was carried out according to the following methods.

(1) Flatness The surface of a small piece of film is sputtered with aluminum and irradiated with differential interference light with an optical microscope, and the magnification is 200 mm and 3 mm.
Observe a range of × 3 mm.

Particles which can be recognized as protrusions are counted to evaluate the flatness of the film. <Four-level judgment> ◎ Number of protrusions is 30 / mm ² or less ○ Number of protrusions is 31 to 60 / mm ² × Number of protrusions is 61 to 150 / mm ² × × Number of protrusions exceeds 150 / mm ² . thing

(2) Intrinsic viscosity number [η] Polymer is phenol / tetrachloroethane = 50/5
It is dissolved in a mixed solvent of 0 (weight ratio) and measured at 35 ° C.

(3) Evaluation of foreign matter in film The polymer is dried at 180 ° C. and then melt-extruded at 308 ° C. After being discharged for 12 hours after the start of discharge, it becomes a sheet,
Subsequently, it is biaxially stretched at a temperature of 130 to 135 ° C. in a longitudinal stretching ratio of 3.5 times and a transverse stretching ratio of 4.0 times, and further heat-set to a thickness of 12.
The film has a thickness of μm.

Next, the film is microscopically observed under polarized light.
The following determination is made with a fish eye in which foreign matter (scale) particles are present at a position where polarized light is applied. Special grade: fisheyes 2 pcs / 50 cm ² less than 1 grade: fisheyes 3-5 Ke / 50 cm ² 2 Grade: fisheyes 5-10 Ke / 50 cm ² 3 Grade: fisheyes 11 Quai / 50 cm ² or more still 1st grade and above are put to practical use.

[0035]

Example 1 100 parts of 2,6-naphthalenedicarboxylic acid ester and 60 parts of ethylene glycol, 0.029 parts (1.2 mol) of manganese acetate tetrahydrate and 0.001 part (0.12 mol) of potassium acetate. Is used as a transesterification catalyst to carry out a transesterification reaction according to a conventional method, and then 0.022 parts (1.6 mol) of trimethyl phosphate
Was added to substantially end the transesterification reaction.

Then, 0.023 part (0.8 mol) of antimony trioxide was added, and subsequently polycondensation reaction was carried out in a usual manner under high temperature and high vacuum to obtain polyethylene naphthalate having an intrinsic viscosity of 0.62 dl / g. . The polymerization time, that is, the time from the start of vacuum suction until the predetermined stirring power was reached was 110 minutes. The properties of the obtained polyethylene naphthalate are shown in Table 1.

[0037]

Example 2 0.003 part (0.27 mol) of potassium acetate and 0.025 part (1.
Polyethylene naphthalate was obtained in the same manner as in Example 1 except that the amount was 8 mol). The polymer properties are shown in Table 1.
Shown in.

[0038]

Example 3 0.0003 parts (0.03) of potassium acetate
(Mole), and in the same manner as in Example 1 to obtain polyethylene naphthalate. The polymer properties are shown in Table 1.

[0039]

Example 4 Polyethylene naphthalate was obtained in the same manner as in Example 1 except that the amount of trimethyl phosphate was changed to 0.036 parts (2.6 mol). The polymer properties are shown in Table 1.

[0040]

Comparative Example 1 Potassium acetate 0.005 parts (0.48 mol) and trimethyl phosphate 0.034 parts (2.
Polyethylene naphthalate was obtained in the same manner as in Example 1 except that the amount was 4 mol). The polymer properties are shown in Table 1.
Shown in.

[0041]

Comparative Example 2 Polyethylene naphthalate was obtained in the same manner as in Example 1 except that the amount of trimethyl phosphate was 0.015 parts (1.1 mol). The polymer properties are shown in Table 1.

[0042]

Comparative Example 3 Polyethylene naphthalate was obtained in the same manner as in Example 1 except that trimethyl phosphate was changed to 0.20 parts (14.0 mol). The polymer properties are shown in Table 1.

[0043]

Comparative Example 4 Antimony trioxide was added in an amount of 0.047 part (1.6
Polyethylene naphthalate was obtained in the same manner as in Example 1 except that the amount was changed to mol). The polymer properties are shown in Table 1.

[0044]

Comparative Example 5 Polyethylene naphthalate was obtained in the same manner as in Example 1 except that potassium acetate was changed to sodium acetate trihydrate and 0.002 parts (0.12 mol) was added. The polymer properties are shown in Table 1.

[0045]

[Table 1]

As shown in Table 1, the surface flatness of the film obtained using the polyethylene naphthalate of the present invention was extremely good. Furthermore, there are few foreign substances in the film,
The quality was satisfactory.

[0047]

According to the method of the present invention, it is possible to produce polyethylene naphthalate in which the generation of residual particles due to the catalyst is extremely small, and the polyethylene naphthalate has a surface flatness as a molded article, especially as a film. Is good and the industrial value is extremely high.

Claims (1)

[Claims] 1. When a lower alkyl ester of naphthalenedicarboxylic acid is reacted with ethylene glycol to produce polyethylene naphthalate, a manganese compound, a potassium compound, a phosphorus compound and an antimony compound are added to the following formulas (1) to (4): A method for producing polyethylene naphthalate, characterized in that it is added in a ratio satisfying [Equation 1] (However, Mn is the number of moles of the manganese compound per 10 ⁶ g of the acid component, K is the number of moles of the potassium compound per 10 ⁶ g of the acid component, P is the number of moles of the phosphorus compound per 10 ⁶ of the acid component, Sb is the number of moles of the antimony compound per 10 ⁶ g of the acid component.)