JP3273991B2 - Method for producing polyethylene naphthalate - Google Patents

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 a product having excellent surface flatness and a special film.

[0002]

2. Description of the Related Art Polyethylene naphthalate film is
Compared to polyethylene terephthalate film, it is superior in basic physical properties such as heat resistance and strength. Therefore, its use in various applications such as a magnetic recording medium, a capacitor, and an electrification tape has been studied and many proposals have been made.

[0003] However, when used as a base film of a magnetic recording medium, a flat surface is required, but a conventional polyethylene naphthalate film cannot sufficiently achieve the surface flatness required especially for a base film of a vapor-deposited video tape. Did not. It is believed that this is because the components used as the catalyst precipitate or form compounds and the like with the polymer components, thereby generating fine irregularities on the film surface.

Conventionally, various attempts have been made to optimize the catalyst addition amount and the addition method in order to ensure the surface flatness of such a film. However, regarding polyethylene naphthalate, this has been sufficiently investigated. The fact is that satisfactory results have not been obtained.

[0005]

DISCLOSURE OF THE INVENTION In view of the above-mentioned circumstances, the present inventors have conducted intensive studies to develop a molded article having excellent surface flatness, particularly polyethylene naphthalate capable of forming a film. By using polyethylene naphthalate produced by a method of adding a compound, a potassium compound, a phosphorus compound, and an antimony compound in a specific amount and a specific ratio as a catalyst, it is possible to obtain a polyethylene naphthalate molded article having excellent surface flatness, particularly a film. And found that the present invention was achieved.

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

[0007]

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

[0008]

(Equation 2)

(Where 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, and P is the number of moles of the acid component 1 of the phosphorus compound.
0 per ⁶ moles, Sb is antimony compound, is the molar number per acid component 10 ⁶ g. )

In the present invention, examples of the naphthalenedicarboxylic acid include 2,6-naphthalenedicarboxylic acid,
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 naphthalenedicarboxylic acid include dimethyl ester, diethyl ester, dipropyl ester and the like, and dimethyl ester is particularly preferred.

In the present invention, a lower alkyl ester of naphthalenedicarboxylic acid is reacted with ethylene glycol to form 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 with another acid component, and a part of ethylene glycol (for example, 20
Mol% or less) may be replaced with another glycol component.

Other acid components include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, diphenylethane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, anthracene dicarboxylic acid and the like. Aliphatic dicarboxylic acids such as adipic acid;
Sebacic acid and the like; alicyclic dicarboxylic acids such as cyclohexane-1,4-dicarboxylic acid;

Other glycol components include aliphatic glycols such as polymethylene glycol having 3 to 10 carbon atoms such as trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol and the like, cyclohexanedimethanol and the like. Aromatic diols such as hydroquinone;
Resorcinol, 2,2-bis (4-hydroxyphenyl)
Propane and the like; aliphatic diol having an aromatic ring such as 1,
4-dihydroxymethylbenzene and the like; polyalkylene glycol (polyoxyalkylene glycol) such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol;

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 can be copolymerized or combined at 20 mol% or less based on the total amount of the components.

Further, in the present invention, the amount of polyethylene naphthalate obtained is substantially linear.
For example, a tri- or higher functional polycarboxylic acid or polyhydroxy compound such as trimellitic acid or pentaerythritol can be copolymerized in an amount of 2 mol% or less based on the total acid component.

In the present invention, in the reaction of the lower alkyl ester of naphthalenedicarboxylic acid with ethylene glycol, first, a manganese compound soluble in the reaction system in an amount of 0.4 to 4.0 mol is added to the acid component. (Hereinafter, the term "mol" 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 is deteriorated when formed into a film due to the effect of precipitated particles due to the catalyst residue. If it is less than 4 moles, 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. Particularly preferably, it is in the range of 0.05 to 0.2.
Even if this molar ratio exceeds 0.25 or less than 0.01,
The surface flatness when formed into a film is deteriorated due to the effect of the catalyst residue.

Next, when the transesterification reaction is substantially completed, a phosphorus compound is added to deactivate a part of the transesterification reaction catalyst. And the molar ratio of the total amount of half of the potassium compound is
0.1-0.8 is preferred. 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. An antimony compound is added to the reaction product as a main catalyst for the polycondensation reaction. The amount is
0.2 to 1.45 mol is preferred. When this amount exceeds 1.45 mol, when the film is formed for a long time,
Precipitates caused by the antimony compound become film defects, while if less than 0.2 mol, the polycondensation reaction is inferior,
The productivity is poor, which is substantially undesirable.

The manganese compound and potassium compound used in the present invention are not particularly limited, but are preferably oxides, chlorides, carbonates, carboxylate salts, etc., and particularly preferably acetate salts, ie, manganese acetate and potassium acetate. .

The phosphorus compound is not particularly limited, but is preferably trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, etc., and particularly preferably trimethyl phosphate.

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 a heat stabilizer, a light stabilizer, an antioxidant, and a light-shielding agent (eg, carbon black, titanium dioxide, etc.) can be added as necessary.

The polyethylene naphthalate obtained in the present invention has no or very little amount of polymer insolubles caused by the catalyst, and is particularly useful as a raw material for film forming.

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

[0028]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples unless it exceeds the gist of the invention.

In the examples, "parts" means parts by weight. The measurement of each characteristic value in the examples was performed according to the following method.

(1) Flatness The surface of a small piece of film was subjected to aluminum spattering and irradiated with differential interference light by an optical microscope while magnifying 200 mm by 3 mm.
Observe a range of × 3 mm.

Particles that can be recognized as protrusions are counted, and the flatness of the film is evaluated. <Four-step judgment> ◎ The number of projections is 30 / mm ² or less ○ The number of projections is 31 to 60 / mm ² × The number of projections is 61 to 150 / mm ² XX The number of projections exceeds 150 / mm ² thing

(2) Intrinsic viscosity number [η] The polymer is phenol / tetrachloroethane = 50/5
Dissolve in 0 (weight ratio) mixed solvent and measure at 35 ° C.

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

Next, the film is observed with a microscope under polarized light,
The following determination is made using fish having foreign matter (scale) particles in the portion where the polarized light is applied as fish eyes. Special grade: Fish eyes are less than 2 pieces / 50 cm ² First grade: Fish eyes are 3-5 pieces / 50 cm ² Second grade: Fish eyes are 5-10 pieces / 50 cm ² Third grade: Fish eyes are 11 pieces / 50 cm ² or more Class 1 or higher is put to practical use.

[0035]

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

Next, 0.023 part (0.8 mol) of antimony trioxide was added, and 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 reaching the predetermined stirring power was 110 minutes. Table 1 shows the properties of the obtained polyethylene naphthalate.

[0037]

Example 2 0.003 parts (0.27 mol) of potassium acetate and 0.025 parts (1.
8 mol) to obtain polyethylene naphthalate. Table 1 shows the polymer properties.
Shown in

[0038]

Example 3 Potassium acetate was added in an amount of 0.0003 parts (0.03 parts).
Mol), to obtain polyethylene naphthalate. The polymer properties are shown in Table 1.

[0039]

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

[0040]

Comparative Example 1 0.005 parts (0.48 mol) of potassium acetate and 0.034 parts of trimethyl phosphate (2.
4 mol) to obtain polyethylene naphthalate. Table 1 shows the polymer properties.
Shown in

[0041]

Comparative Example 2 A polyethylene naphthalate was obtained in the same manner as in Example 1 except that 0.015 parts (1.1 mol) of trimethyl phosphate was used. 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 0.20 part (14.0 mol) of trimethyl phosphate was used. The polymer properties are shown in Table 1.

[0043]

Comparative Example 4 0.047 parts of antimony trioxide (1.6
Mol), to obtain polyethylene naphthalate. 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 by 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 having extremely small generation of residual particles due to the catalyst, and the polyethylene naphthalate can be used as a molded product, especially as a film, and its surface flatness can be improved. But the industrial value is very high.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (1)

(57) [Claims] 1. When producing a polyethylene naphthalate by reacting a lower alkyl ester of naphthalenedicarboxylic acid with ethylene glycol, a manganese compound, a potassium compound, a phosphorus compound and an antimony compound are converted into the following formulas (1) to (4). A method for producing polyethylene naphthalate, characterized by adding at a ratio satisfying the following. (Equation 1) (However, Mn is the manganese compound, the molar number per acid component 10 ⁶ g, the K is potassium compound, moles per acid component 10 ⁶ g, P is the phosphorus compound, the number of moles of the acid component 10 per ^6, Sb is the number of moles of the antimony compound per 10 ⁶ g of the acid component.)