JP3056673B2 - Polyethylene naphthalate for bottles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer of polyethylene naphthalene dicarboxylate (hereinafter abbreviated as polyethylene naphthalate or PEN), and more particularly to a bottle having good thermal stability, excellent hue and transparency. It relates to PEN suitable for molding materials.

[0002]

2. Description of the Related Art PEN
Is useful as a packaging material for bottles (containers), sheet materials, and the like because it has superior heat resistance, gas barrier properties, chemical resistance, and other basic physical properties as compared with polyethylene terephthalate (hereinafter abbreviated as PET). This is expected, and many proposals have been made by blending with PET or using alone. Among packaging materials, 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 reacted with the same catalyst system as basic PET, and it is expected that germanium dioxide is particularly effective as a polymerization catalyst from the viewpoint of hue. However, PEN is Compared with PET, whitening is likely to occur in a blow stretching or the like at the time of bottle molding, those are the Most concerns such obtained capable of satisfying bottle charged amount in terms of transparency (products) in our study .

[0003] Subsequently, 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 extremely large as compared with PET, and that the influence was likely to be easily caused. 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 of PEN was certainly improved. However, hue and thermal stability are not sufficiently satisfactory.
In order to suppress the formation of precipitates, the amount of the phosphorus compound used to deactivate the transesterification catalyst is less than the equimolar amount, and the catalytic action is not completely deactivated. , Its decomposition rate increases.

[0004] Furthermore, if the melt viscosity of the polymer is not appropriate during the molding of the bottle, the smoothness and uniform wall thickness of the bottle cannot be ensured, or the haze is significantly deteriorated and clouding occurs, so that the range must be limited. is there.

[0005] The present inventors have conducted intensive studies in view of the above-mentioned circumstances, and as a result, in a test in which the species, amount and ratio of a specific catalyst are added, the amount of the phosphorus compound is at least equal to that of the transesterification catalyst. It has been found that by adding a mole, and further forming a polymer having an appropriate viscosity, a polyethylene naphthalate-based composition having good thermal stability, hue, and transparency, and excellent in bottle moldability can be obtained. Reached.

[0006]

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 the catalyst is a cobalt compound, a magnesium compound, a calcium compound, a phosphorus compound. The compound and the germanium compound contain an amount satisfying the following (1) to (5) at the same time, and the intrinsic viscosity [η] of the polymer used for the bottle
Is polyethylene naphthalenedicarboxylate for bottles satisfying the following general formula (6).

[0007]

## EQU2 ## 0.05 ≦ Co ≦ 0.40 mol (1) 2.0 ≦ (Mg + Ca) ≦ 6.0 mol (2) 1.3 ≦ (Mg / Ca) ≦ 6.0 (3) 0 ≦ P / (Co + Mg + Ca) ≦ 1.5 (4) 1.0 ≦ Ge ≦ 3.0 mol (5) (Each metal element in the above formula represents the number of moles of metal per 10 ⁶ g of the acid component. 0.60 ≦ [η] ≦ 0.80 (6) (However, the intrinsic viscosity [η] is determined from the solution viscosity measured at 35 ° C. using a phenol / tetrachloroethane (component ratio: 3/2) solvent). The present invention will be described below.

[0008] The term "principal" as used herein means greater than 70 mol%, preferably greater than 80 mol%. Therefore, less than 30 mol% of other components may be contained as a copolymer or a mixture.

In the present invention, “naphthalenedicarboxylic acid” refers to, for example, 2,6-naphthalenedicarboxylic acid,
The main target is 2,7-naphthalenedicarboxylic acid and its ester-forming derivative, but a part thereof (30 mol%
Less than) other dicarboxylic acids, such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid and other aliphatic dicarboxylic acids;
Aromatic dicarboxylic acids such as isophthalic acid, 4,4'-diphenyldicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, diphenylether-4,4'-dicarboxylic acid An alicyclic dicarboxylic acid such as hexahydroterephthalic acid, decalin dicarboxylic acid, or teleralin dicarboxylic acid; or an oxyacid such as glycolic acid or p-oxybenzoic acid. Examples of the ester-forming derivative of the acid component include lower alkyl esters, phenyl esters, and acid anhydrides.

The term "glycol component" mainly refers to ethylene glycol, and part (less than 30 mol%) of other glycols such as tetramethylene glycol, propylene glycol, 1,3-butanediol, Aliphatic thiols such as pentyl glycol; alicyclic diols such as cyclohexane dimethanol and tricyclodecane dimethylol; aromatic diols such as bisphenol A, bisphenol S, bishydroxyethoxybisphenol A, tetrabromobisphenol A, etc. Good.

Further, in the present invention, a tricarboxylic or polyfunctional polycarboxylic acid or polyhydroxy compound, such as trimellitic acid, is used in an amount in a substantially linear range, for example, an amount of 2 mol% or less based on the total acid components. And pentaerythritol and the like.

In the case of the transesterification method in the present invention, the lower alkyl ester of naphthalenedicarboxylic acid and usually ethylene glycol are added in an amount of 0.1 to 10 ⁶ g of the acid component.
0.5 to 0.4 mol of the cobalt compound and 2.0 to 6.0 mol.
The total amount of the moles of the calcium compound and the magnesium compound is added as a transesterification catalyst (hereinafter, mole indicates 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 is a cause of the deterioration of the hue, in addition to the effect of the transesterification catalyst, and the addition amount is 0.05%.
When the amount is less than mol, the effect is not exhibited, and when it exceeds 0.4 mol, the hue becomes grayish, 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 the molding due to the influence of the precipitated particles due to the catalyst residue, and the transparency is unfavorably deteriorated. On the other hand, if it is less than 2.0 mol, not only the transesterification reaction becomes insufficient, but also the subsequent polymerization reaction is unfavorably slow. The molar ratio of the amount of the magnesium compound to the calcium compound is in the range of 1.3 to 6.0.
Particularly preferably, it is in the range of 1.4 to 4.0. Even if the molar ratio exceeds 6.0 or less than 1.3, precipitation of particles due to catalyst residues occurs, and when molded, a whitening phenomenon is observed.
Transparency is impaired. In order to further deactivate the transesterification catalyst, a phosphorus compound is added.
The total amount of the calcium compound and the magnesium compound needs to be in the range of 1.0 to 1.5, and more preferably in the range of 1.1 to 1.3. If the molar ratio is less than 1.0, the transesterification catalyst will not be completely deactivated, and the thermal stability will be poor. vice versa,
If it exceeds 1.5, thermal stability is poor, which is not preferable.

The calcium compound and the magnesium compound used in the present invention can be used as oxides, chlorides, carbonates, carboxylate and the like, and are not particularly limited. However, acetates, particularly calcium acetate and magnesium acetate, are particularly preferred.

Examples of the phosphoric acid include orthophosphoric acid, phosphoric acid acid ester and phosphoric acid triester. Among them, trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, and phosphate esters in which at least one group is replaced by a hydroxyalkyl group or a hydroxy (polyalkylene glycol) group are preferred.

Further, the intrinsic viscosity of the polymer [η] (dl /
It is particularly important for molding a PEN bottle that g) be limited to the following formula so that the melt viscosity of the polymer at the time of molding the bottle is in an appropriate range. 0.60 ≦ [η] ≦ 0.80 (6) (Intrinsic viscosity [η] is calculated from the solution viscosity measured at 35 ° C. using a solvent of phenol / tetrachloroethane (component ratio: 3/2). If a polymer with [η] <0.60 is used as a bottle, the polymer tends to crystallize during molding, causing whitening, and also has a too low melt viscosity to make blow molding difficult. Even if blow molding can be achieved, the mechanical strength of the bottle is low and only a fragile product can be obtained.

Conversely, when a polymer having [η]> 0.80 is subjected to extrusion molding of a preform at a normal molding temperature, the melt viscosity of the PEN polymer is too high to obtain a preform having good processability. It is difficult. Therefore, in order to lower the melt viscosity, a method such as raising the molding temperature is required.
You. However, in this method, even if the polymer has been optimized as described above, the intrinsic viscosity [η] decreases sharply due to thermal degradation and the yellow color becomes strong, and the polymer cannot be used as a bottle polymer.

On the other hand, in order to obtain a polymer having an intrinsic viscosity represented by the above formula (6), it is preferable that a polymer having a lower intrinsic viscosity [η] _p obtained by melt polymerization is raised by solid-phase polymerization. . If the PEN polymer is increased by melt polymerization to the range of the intrinsic viscosity that can be generally used for bottles, the coloration of the polymer will increase, or the melt polymerization will be too high and the burden on the equipment will increase, which is not recommended. Since the amount of aldehydes in the polymer is also large, only a very poor polymer can be obtained as a polymer for bottles.

From this, the intrinsic viscosity [η] _p of the prepolymer at the time of completion of the melt polymerization is expressed by the following equation (7).
The PEN polymer obtained by solid-state polymerization of the above-mentioned compound is preferably provided in a bottle. 0.40 ≦ [η] _p ≦ 0.65 (7)

The reason for setting the range of [η] _p of the prepolymer as described above is that , when [η] _p <0.40, cracks frequently occur during chip formation and uniform chips cannot be obtained, This is because the load of the phase polymerization increases and the productivity decreases, which is not preferable.

When [η] _p > 0.65, as described above, it is not preferable in terms of coloring and generation of aldehydes. The smaller the amount of aldehydes, the better, but it is necessary to control the content to at least 25 ppm, preferably 15 ppm, in consideration of flavor when using a bottle.

As the polymerization reaction catalyst, germanium dioxide is preferably used as a germanium compound from the aspect of hue, and among them, it does not have a crystalline form.
When so-called amorphous germanium dioxide is used, a polymer having less precipitated particles of the polymer and a higher transparency can be obtained as compared with those having a normal crystal form. The term “amorphous” as used herein refers to a substance having substantially no peak in a Raman spectrum. As the amount of amorphous germanium dioxide added, if too small, the polymerization reactivity becomes low and the productivity is poor, and if too large, on the other hand, thermal stability is inferior, leading to deterioration in physical properties during molding and deterioration of hue, Acid component 10 ⁶
A range of substantially 1.0 to 3.0 mol per g is preferred. It is preferable that the addition of the various catalyst systems described above be completed in the cobalt compound, the calcium compound, and the magnesium compound during the period from the start of the transesterification reaction to the initial stage, and the order of addition of the three compounds is particularly limited. However, they may be added alone or simultaneously.

Further, it is preferable to add an ammonium compound represented by the following chemical formula I for the purpose of enhancing the effect of suppressing the precipitation of precipitated particles by the transesterification catalyst and further dispersing the precipitated particles finely.

[0023]

Embedded image

(However, R ₁ , R ₂ , R ₃ and R ₄ are a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or a substituted derivative thereof, and R ₃ and R ₄ form a ring. And R ₁ , R ₂ , R ₃ and R ₄ may be the same or different, and A represents an anionic residue.)

Specific examples of the ammonium compound include quaternary ammonium salts such as hydroxytetramethylammonium, hydroxytetraethylammonium, hydroxytetrabutylammonium and tetraethylammonium chloride; tertiary ammonium salts such as hydroxytrimethylammonium Secondary ammonium salts such as hydroxydimethylammonium salts; primary ammonium salts such as hydroxymethylammonium and the like, and ammonium salts such as hydroxyammonium and ammonium chloride. The above-mentioned ammonium compounds may be used alone or in combination of two or more.

The amount of the ammonium compound is 0.04 to 0.4 mol per 10 ⁶ g of the acid component. The preferred range is from 0.07 to 0.2 mole. If it is less than 0.04 mol, the effect of suppressing precipitation of catalyst particles and the effect of finely dispersing the catalyst particles is small,
Transparency is not very good. On the other hand, if it exceeds 0.4 mol, the effect is not particularly enhanced, and on the contrary, the polymerization reactivity is deteriorated.

On the other hand, the ammonium compound and the phosphorus compound can be added until the intrinsic viscosity reaches 0.2 dl / g after the transesterification reaction is substantially completed. The order of addition is not particularly limited, but it is preferable to add the ammonium compound before adding the phosphorus compound.

The germanium compound is added at least 10 minutes after the addition of the phosphorus compound and before the intrinsic viscosity reaches 0.3. The atmosphere of the reaction system at the time of addition may be under atmospheric pressure before the start of the polycondensation reaction,
It may be under reduced pressure after the start of the polycondensation reaction.

The polymer obtained above may be subjected to a solid phase polymerization by a known method, if necessary.

[0030]

The present invention will be described more specifically with reference to the following examples. In the examples, "parts" means parts by weight.
Further, the measurement of each characteristic value in the embodiment is performed by the following method. Intrinsic viscosity [η]: Calculated from solution viscosity measured at 35 ° C. using a phenol / tetrachloroethane (component ratio: 3/2) solvent. Colb (hue): The polymer is heat-treated in a dryer at 160 ° C. for 90 minutes to be crystallized, and then measured using a color machine CM-7500 type color machine. Molded product haze: After drying the polymer at 160 ° C for 7 hours, an injection molding machine Dynamelter M-1 manufactured by Meiki Seisakusho
50 at a cylinder temperature of 300 ° C. using 00DM
g of preform was molded and blow-stretched to obtain a bottle having an inner volume of 1.5 liter and a body thickness of 0.2 mm. This straight body is cut out, and the haze is measured using a haze meter (Nippon Denshoku Industries Model 1001DP).

Example 1 100 parts of 2,6-naphthalenedicarboxylic acid dimethyl ester and 51 parts of ethylene glycol (abbreviated as EG) were mixed with 0.005 part (0.2 mol) of cobalt acetate tetrahydrate, A transesterification reaction was carried out according to a conventional method using 0.014 parts (0.8 mol) of calcium acetate-water salt and 0.044 parts (2.1 mol) of magnesium acetate tetrahydrate as a transesterification catalyst, and then hydroxytetraethyl was used. 0.012 parts (0.08 mol) of a 10% aqueous solution of ammonium (hereinafter abbreviated as EA agent) was added, and 5 minutes later, 0.047 parts (3.4 mol) of trimethyl phosphate was added, and substantially Then, the transesterification was terminated. The final reaction temperature at this time was 245 ° C. Next, 1.58 parts (1.6 mol) of a 1% solution of amorphous germanium dioxide in EG was added, and then a polycondensation reaction was carried out in a usual manner under a high temperature and high vacuum. A strand-type chip was formed by a withdrawal pelletizer. The intrinsic viscosity [η] _p of the polymer obtained at this time was 0.50. This chip was subjected to solid-state polymerization at 225 ° C. under a high vacuum of 1.0 mmHg to increase the intrinsic viscosity [η] of the polymer to 0.70.

Examples 2 to 5, Comparative Examples 1 to 9 Cobalt acetate tetrahydrate, magnesium acetate tetrahydrate, calcium acetate-hydrate, and trimethyl phosphate were changed as shown in Table 1, or solid phase was changed. The procedure was basically the same as in Example 1, except that [η] of the polymer after polymerization was changed as shown in Table 1. Table 1 also shows the obtained polymer quality and each evaluation result.

[0033]

[Table 1]

As can be seen from these results, when the amount of the catalyst is too small, the reactivity is poor [Comparative Examples 1 and 7], and there is a problem in the productivity. If [Comparative Examples 3 and 4] and the P / (Co + Ca + Mg) ratio [Comparative Examples 5 and 6] are not appropriate, transparency and / or hue will be deteriorated.

If the [η] _p after the solid-phase polymerization is not appropriate, the viscosity is too low or too high to form a bottle, and even if it can be formed, the uneven thickness is severe. Some of them are weak and have low strength [Comparative Examples 8 and 9].

[0036]

The polyethylene naphthalate of the present invention is
It is excellent in hue and transparency, has little whitening (cloudiness) at the time of bottle formation, and can be a bottle product with high commercial value.

(56) References JP-A-6-116378 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 63/00-63/91 C08J 5/00 C08L 67 / 00-67/02

Claims (5)

(57) [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 a germanium compound as catalysts are represented by the following (1) to (1). A polyethylene naphthalenedicarboxylate for a bottle, which contains an amount satisfying (5) at the same time and further has an intrinsic viscosity [η] of a polymer used for the bottle satisfying the following general formula (6). 0.05 ≦ Co ≦ 0.40 mol (1) 2.0 ≦ (Mg + Ca) ≦ 6.0 mol (2) 1.3 ≦ (Mg / Ca) ≦ 6.0 (3) 0 ≦ P / (Co + Mg + Ca) ≦ 1.5 (4) 1.0 ≦ Ge ≦ 3.0 mol (5) (However, each metal element in the above formula indicates the number of moles of metal per 10 ⁶ g of the acid component. 0.60 ≦ [η] ≦ 0.80 (6) (However, the intrinsic viscosity [η] is determined from the solution viscosity measured at 35 ° C. using a phenol / tetrachloroethane (component ratio: 3/2) solvent). calculate.) 2. The bottle according to claim 1, wherein the intrinsic viscosity [η] _{p of} the prepolymer obtained by melt polymerization satisfies the following general formula (7), and the prepolymer is obtained by solid-state polymerization. Polyethylene naphthalene dicarboxylate. 0.40 ≦ [η] _p ≦ 0.65 (7) 3. Acetaldehyde (AA) in a polymer
2. The polyethylene naphthalenedicarboxylate for a bottle according to claim 1, wherein the concentration of satisfies the following formula (8). 0 <AA ≦ 25 ppm (8) 4. The polyethylene naphthalenedicarboxylate for a bottle according to claim 1, wherein the germanium compound is amorphous germanium dioxide having no substantial peak in Raman spectrum analysis. 5. The polyethylene naphthalenedicarboxylate for a bottle according to claim 1, wherein an ammonium compound represented by the following chemical formula I is compounded in an amount of 0.04 to 0.4 mol per 10 ⁶ g of the acid component. Embedded image (However, R ₁ , R ₂ , R ₃ and R ₄ are a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or a substituted derivative thereof, and R ₃ and R ₄ may form a ring,
R ₁ , R ₂ , R ₃ and R ₄ may be the same or different. A represents an anion residue. )