JPH10245433A - Polyethylene naphthalate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyethylene naphthalate (PEN) having good thermal stability and excellent hue and transparency for packaging materials such as bottles and sheets. The catalyst contains Co, Mg, Ca, P compounds and Sb compounds in amounts satisfying the following formula. 0.08 ≦ Co ≦ 1.2 mol... (1) 2.0 ≦ (Mg + Ca) ≦ 6.0 mol... (2) 1.3 ≦ (Mg / Ca) ≦ 6.0 (3) 1.0 ≦ P / (Co + Ca + Mg) ≦ 1.5 ・ ・ ・ (4) 0.8 ≦ Sb ≦ 3.0 mol ・ ・ ・ ・ (5) (However, mol is 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 polyethylene naphthalene dicarboxylate (hereinafter abbreviated as polyethylene naphthalate or PEN), and more particularly, it has good thermal stability, excellent hue and transparency, and is used for bottles and sheets. The present invention relates to a PEN suitable for molding a packaging material.

[0002]

2. Description of the Related Art PEN is superior to polyethylene terephthalate (hereinafter abbreviated as PET) in terms of heat resistance, gas barrier properties, chemical resistance, ultraviolet cut properties, refractive index, and other basic physical properties. Many proposals have been made by blending with PET or using alone. Above all, as for materials used for beverage bottles such as juices, materials excellent in hue and transparency are strongly demanded from the viewpoint of commercial value. PEN can be basically reacted with the same catalyst as PET, and it is predicted that the use of antimony trioxide as a polymerization catalyst is particularly effective from the aspects of hue and cost.

[0003]

However, PEN
Compared to PET, whitening tends to occur during blow-stretching or the like at the time of bottle molding, and there is a problem in our research that a sufficiently satisfactory bottle (product) cannot be obtained in terms of transparency. As a result of elucidating the cause of the whitening, it was presumed that the internal haze was caused by the catalyst precipitate caused by the catalyst and the crystallization was induced by the catalyst precipitate particles. In particular, in the case of PEN, it was presumed that the stress at the time of forming (stretching) the bottle was much larger than that of PET, and that the influence was likely to occur. That is, in order to suppress whitening, it is necessary to reduce the amount of precipitates caused by a catalyst or the like. As a means for this, it has been proposed to limit a specific catalyst type, amount, and ratio. The transparency has certainly improved. However, they are not sufficiently satisfactory in terms of hue and thermal stability.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above circumstances, and found that the amount of a phosphorus compound used to deactivate a transesterification catalyst in order to suppress the formation of precipitates is equal. If the amount is less than the molar amount and the catalytic action is not completely deactivated, the decomposition rate is increased during molding of the polymer, etc., and the hue and heat stability are found to be insufficient. Examining the ratio, it was found that by adding at least an equimolar amount of the phosphorus compound compared to the amount of the transesterification catalyst, it is possible to obtain polyethylene naphthalate having good thermal stability and excellent hue and transparency. Was.

That is, the present invention relates to a polyester comprising naphthalenedicarboxylic acid as a main acid component and ethylene glycol as a main glycol component, wherein a cobalt compound, a magnesium compound, a calcium compound, a phosphorus compound and an antimony compound as catalysts are represented by the following formula: (1)-
It is a polyethylene naphthalate containing (5) at the same time. 0.08 ≦ Co ≦ 1.2 mol (1) 2.0 ≦ (Mg + Ca) ≦ 6.0 mol (2) 1.3 ≦ (Mg / Ca) ≦ 6.0 (3) 1.0 ≦ P / (Co + Ca + Mg) ≦ 1.5 (4) 0.8 ≦ Sb ≦ 3.0 mol (5) (However, in the above formula, Each metal element indicates the number of moles per 10 ⁶ g of the acid component.)

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below. In the present invention, "main" means 70 mol% or more, preferably 80 mol% or more. Therefore, less than 30 mol% of other components may be contained as a copolymer or a mixture.

The polyethylene naphthalate in the present invention is mainly intended for a homopolymer of polyethylene-2,6-naphthalenedicarboxylate.
Part of the 6-naphthalenedicarboxylic acid component (less than 30 mol%) is 2,7-, 1,5-, 1,7-other isomers of naphthalenedicarboxylic acid or terephthalic acid or isophthalic acid, diphenyldicarboxylic acid Other aromatic dicarboxylic acids such as diphenoxyethane dicarboxylic acid, diphenyl ether dicarboxylic acid and diphenyl sulfone dicarboxylic acid; alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid; adipic acid;
It may be replaced by another difunctional carboxylic acid such as an aliphatic dicarboxylic acid such as sebacic acid or azelaic acid; or an oxy acid such as p-β-hydroxyethoxybenzoic acid or ε-oxycaproic acid.

Further, a part of the ethylene glycol component is, for example, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, diethylene glycol,
Other polyfunctional such as 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2-bis (4′-β-hydroxyphenyl) propane, bis (4′-β-hydroxyethoxyphenyl) sulfonic acid The copolymer may be substituted with one or more compounds and copolymerized in a range of less than 30 mol%.

The polyethylene naphthalate of the present invention is produced by subjecting an ester-forming derivative of the above-mentioned acid component, for example, a di-lower alkyl naphthalate and a glycol such as ethylene glycol to a transesterification reaction, followed by polycondensation. In the transesterification reaction, a lower alkyl ester of naphthalenedicarboxylic acid and ordinary ethylene glycol are added to the acid component per 10 ⁶ g,
0.08 to 1.2 moles of the cobalt compound and 2.0 to
The total amount of 6.0 moles of calcium compound and magnesium compound is added as a transesterification catalyst. The term "mol" means the number of moles per 10 ⁶ g of the acid component.

Here, the purpose of adding the cobalt compound is to suppress the yellowing which causes the deterioration of the hue in addition to the effect of the transesterification catalyst. Is not developed, and when the amount exceeds 1.2 mol, the hue becomes gray and the hue is deteriorated. On the other hand, when the total amount of the calcium compound and the magnesium compound exceeds 6.0 mol, a whitening phenomenon is observed in molding due to the effect of precipitated particles due to the catalyst residue, and the transparency is impaired. Conversely, if the amount is less than 2.0 mol, not only the transesterification reaction becomes insufficient, but also the subsequent polymerization reaction becomes slow, which is not preferable.

The molar ratio of the magnesium compound to the calcium compound is in the range of 1.3 to 6.0. If the molar ratio is more than 6.0 or less than 1.3, particles will be precipitated due to the catalyst residue, and when molded, a whitening phenomenon is observed and transparency is impaired.

Further, a phosphorus compound is added to deactivate the transesterification catalyst. The amount (molar ratio) of the phosphorus compound is 1 to the total amount of the cobalt compound, the calcium compound and the magnesium compound. .0
It needs to be in the range of 1.5. If this molar ratio is less than 1.0, the transesterification catalyst will not be completely deactivated and the thermal stability will be poor, resulting in inconvenience that the polymer is colored or the physical properties during molding are reduced. Conversely, if it exceeds 1.5, heat stability is not preferred.

In the present invention, the cobalt compound, calcium compound and magnesium compound include oxides,
Examples include, but are not limited to, chlorides, carbonates, and carboxylate salts, with particular preference being given to acetates, ie, cobalt acetate, calcium acetate and magnesium acetate.

The phosphorus compound includes trimethyl phosphate, triethylene phosphate or tri-n-butyl phosphate and orthophosphoric acid. Preferably it is trimethyl phosphate.

As a polymerization reaction catalyst, antimony trioxide is preferable as an antimony compound from the aspect of hue. If the amount of antimony trioxide is too small, the polymerization reactivity will be low and the productivity will be poor.If the amount is too large, the thermal stability will be poor and the physical properties during molding and the hue will deteriorate. The range is 0.8 to 3.0 mol.

The above-mentioned various catalyst systems are preferably added during the period from the start of the transesterification reaction to the initial stage in the case of the cobalt compound, calcium compound and magnesium compound. On the other hand, the phosphorus compound has an intrinsic viscosity of 0.3 after the transesterification reaction is substantially completed.
Can be added before reaching. The antimony compound has an intrinsic viscosity of 0.1 minutes or more before the addition of the phosphorus compound.
Add until 2 is reached.

The polyethylene naphthalate of the present invention can be produced by a polycondensation method via a conventional transesterification method. For example, a dialkylnaphthalate and ethylene glycol are added to the above-mentioned cobalt compound, calcium compound and magnesium compound in the above-mentioned amount ranges. After the transesterification reaction is substantially completed, an antimony compound in the above-mentioned amount range is added, and before the intrinsic viscosity reaches 0.3, a phosphorus compound is added. Let it undergo a condensation reaction. Further, solid-state polymerization may be performed by a conventional method to increase the intrinsic viscosity.

The polyethylene naphthalate of the present invention thus obtained has an intrinsic viscosity (tetrachloroethane:
Phenol = 4: 6 in a mixed solvent at 35 ° C.)
It is preferably 0.90, more preferably 0.50 to 0.90 for molding packaging materials such as bottles, and 0.40 to 0.60 for molding packaging materials such as sheets.

[0019]

The present invention will be described more specifically with reference to the following examples. In the examples, “parts” is “parts by weight”.

(1) Intrinsic viscosity (IV): Measured at 35 ° C. in a mixed solvent of tetrachloroethane: phenol = 4: 6.

(2) Col-L, b (hue): The polymer is heat-treated in a dryer at 160 ° C. for 90 minutes to crystallize, and then measured using a color machine CM-7500 type color machine.

(3) Haze: After drying the polymer at 160 ° C. for 5 hours, a preform of 55 g was molded at a molding temperature of 300 ° C. using an injection molding machine 100DM manufactured by Meiki Seisakusho, and blow-drawn. , Internal volume 1.5L, body thickness 3
It was a 00 μm bottle. The haze of the body of the bottle was measured with a turbidity meter manufactured by Nippon Denshoku Industries Co., Ltd.

(4) Sheet formability: 160
After drying at 5 ° C for 5 hours, using a film forming machine, forming temperature 300 ° C
To form a sheet having a thickness of 300 μm, and the moldability was evaluated as follows. ：: good, △: moldability is not good due to slightly high viscosity.

Example 1 100 parts of 2,6-naphthalenedicarboxylic acid dimethyl ester and 51 parts of ethylene glycol (abbreviated as EG) were prepared by adding 0.1 part of cobalt acetate tetrahydrate.
005 parts (0.2 mol), calcium acetate monohydrate 0.0
14 parts (0.8 mol) and magnesium acetate tetrahydrate 0.
Using 044 parts (2.1 mol) as a transesterification catalyst, a transesterification reaction was carried out according to a conventional method, and 1.58 parts (1.6 mol) of a 1% solution of antimony trioxide in EG were added, followed by 0.047 parts of trimethyl phosphate. Section (3.4
Mol) was added to terminate the transesterification reaction. Next, a polycondensation reaction is performed under high temperature and high vacuum as usual,
Thereafter, a strand type chip was obtained. The intrinsic viscosity of the obtained polymer was 0.60, and the polymerization time was 120 minutes. The haze after bottle molding was 2.0%. or,
The moldability of the sheet was not good because the viscosity was rather high.

Examples 2 to 5 and Comparative Examples 1 to 9 The amounts and ratios of cobalt acetate tetrahydrate, magnesium acetate tetrahydrate, calcium acetate monohydrate, trimethyl phosphate and antimony trioxide are shown in Table 1. The procedure was basically the same as in Example 1, except for the following changes. Table 1 also shows the obtained polymer quality and each evaluation result.

The product of Example 5 was suitable for forming a sheet even though it could not be formed as a bottle.

[0027]

[Table 1]

As can be seen from these results, if the amount of the polycondensation catalyst is small, the reactivity is poor, causing a problem of productivity (Comparative Examples 1 and 7).
Ca ratio (Comparative Examples 3 and 4), P / (Co + Ca + Mg)
If the ratio (Comparative Examples 5 and 6) is not proper, transparency and / or hue will be deteriorated. Further, even if the above-mentioned addition ratio is appropriate, if the Co is not added in an appropriate amount (Comparative Examples 8 and 9), a sufficiently satisfactory hue cannot be obtained.

[0029]

The polyethylene naphthalate of the present invention is excellent in hue and transparency and can be applied to packaging materials such as bottles or sheet-like packaging materials. In particular, the whitening (cloudiness) at the time of bottle formation is small, and it can be a bottle product with high commercial value.

Claims (2)

[Claims] 1. A polyester comprising naphthalenedicarboxylic acid as a main acid component and ethylene glycol as a main glycol component, wherein a cobalt compound, a magnesium compound, a calcium compound, a phosphorus compound and an antimony compound as catalysts are represented by the following formula (1): Polyethylene naphthalate containing (5) at the same time. 0.08 ≦ Co ≦ 1.2 mol (1) 2.0 ≦ (Mg + Ca) ≦ 6.0 mol (2) 1.3 ≦ (Mg / Ca) ≦ 6.0 (3) 1.0 ≦ P / (Co + Ca + Mg) ≦ 1.5 (4) 0.8 ≦ Sb ≦ 3.0 mol (5) (However, in the above formula, Each metal element indicates the number of moles per 10 ⁶ g of the acid component.) 2. The polyethylene naphthalate according to claim 1, wherein the antimony compound is antimony trioxide.