JP3238642B2 - Polyethylene naphthalene dicarboxylate for bottles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyethylene naphthalene dicarboxylate (hereinafter sometimes abbreviated as polyethylene naphthalate or PEN) polymer,
More specifically, it has good thermal stability, excellent hue and transparency,
Regarding PEN suitable for bottles.

[0002]

2. Description of the Related Art Bottles (PEN) are superior to polyethylene terephthalate (hereinafter sometimes abbreviated as PET) because of their superior physical properties such as heat resistance, gas barrier properties, chemical resistance, ultraviolet ray cutoff, and refractive index. It is expected to be useful for containers), sheet materials, etc., and 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.

[0003] PEN can be basically reacted with a catalyst similar to PET, and it is expected that the use of antimony trioxide as a polymerization catalyst will be particularly effective in terms of hue and cost. However, compared to PET, PEN is more likely to be whitened by blow stretching during bottle molding, etc.
According to the studies by the inventors, a bottle (product) having a satisfactory transparency cannot be obtained.

[0004]

As a result of elucidating the cause of the whitening, the present inventors have found that the internal haze due to the catalyst precipitate caused by the catalyst and the crystallization induced by the catalyst precipitate particles are considered. Was obtained. Especially for PEN, P
It was presumed that the stress at the time of forming (stretching) the bottle was much larger than that of ET, and that the effect 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. It has been proposed to limit the type and amount of a specific catalyst as this means, and this catalyst system certainly improved the transparency of PEN. However, no satisfactory color and heat stability have been obtained yet. This is because the amount of the phosphorus compound used to deactivate the transesterification catalyst in order to suppress the formation of precipitates becomes smaller than a predetermined amount, and the catalytic action is not completely deactivated. On the occasion,
It is estimated that the decomposition rate increases.

If the melt viscosity of the polymer is not appropriate at the time of molding the bottle, the smoothness and uniform thickness distribution of the bottle surface cannot be ensured, or the haze is significantly deteriorated and clouding occurs.

An object of the present invention is to obtain a polyethylene naphthalenedicarboxylate having good thermal stability and excellent hue and transparency.

[0008]

Means for Solving the Problems The inventors of the present invention have made intensive studies in view of the above-mentioned circumstances, and as a result, by optimizing the type and amount of a specific catalyst and the amount of a phosphorus compound, the heat stability and the hue have been improved. It has been found that polyethylene naphthalenedicarboxylate having excellent transparency can be obtained.

That is, according to the present invention, the cobalt compound, the manganese compound, the phosphorus compound and the antimony compound present in polyethylene naphthalenedicarboxylate simultaneously satisfy the following formulas (1) to (4), and have an intrinsic viscosity of the polymer:
[η] is polyethylene naphthalenedicarboxylate for bottles satisfying the following formula (5).

[0010]

0.04 ≦ Co ≦ 2.4 mol (1) 0.6 ≦ Mn ≦ 2.1 mol (2) 0.7 ≦ P / (Co + Mn) ≦ 1.5 (3) 0.8 ≦ Sb ≦ 3.0 mol (4) (However, each metal element in the above formula indicates the number of moles per 10 ⁶ g of the acid component.)

[0011]

0.60 <[η] ≦ 0.80 (5)

Hereinafter, the present invention will be described in detail. In the present invention, the polyethylene naphthalenedicarboxylate is a polyester in which the main dicarboxylic acid component constituting the polyester is naphthalenedicarboxylic acid and the main diol component is ethylene glycol.

The term "main component" as used herein means a component exceeding 70 mol%, preferably a component exceeding 80 mol%, based on all dicarboxylic acid components. Therefore, less than 30 mol% of other components may be contained as a copolymer component or a polymer mixture component.

The polyethylene naphthalenedicarboxylate in the present invention is mainly intended for a homopolymer of polyethylene-2,6-naphthalenedicarboxylate. For example, a part of the 2,6-naphthalenedicarboxylic acid component, for example, 30 mol% Less than 20 mol%, preferably 2,7-, 1,5-, 1,7-other isomers of naphthalenedicarboxylic acid or terephthalic acid or isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyldicarboxylic acid, Other aromatic dicarboxylic acids such as phenoxyethane dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, adipic acid, sebacic acid, azelaic acid Aliphatic dicarboxylic acids such as p-beta-hydroxy ethoxy benzoic acid, may be replaced by other difunctional carboxylic acids, such as such as oxy acids such as ε Okishikapuron acid.

Further, a part of the ethylene glycol component, for example, less than 30 mol%, preferably less than 20 mol%, 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 It may be a copolymer obtained by copolymerizing at least one compound.

When the polyethylene naphthalenedicarboxylate is obtained by the transesterification method according to the present invention, 0.04-2.4 mol of cobalt per 10 ⁶ g of the acid component is added to the lower alkali ester of naphthalenedicarboxylic acid and ordinary ethylene glycol. 0.6 to 0.6 g per 10 ⁶ g of compound and acid component
2.1 mol of a manganese compound are added as a transesterification catalyst.

In the present specification, the amount of the catalyst is 10 ⁶
It is the number of moles per g and is expressed in units of mol / 10 ⁶ g.

The purpose of adding the cobalt compound is to suppress the yellowing, which is a cause of deterioration of the hue, in addition to the effect of the transesterification catalyst.
When the amount is less than mol / 10 ⁶ g, no effect is exhibited. On the other hand, when the amount exceeds 2.4 mol / 10 ⁶ g, the hue becomes gray, resulting in deterioration of the hue or reduction in transparency.

When the total amount of the manganese compounds exceeds 2.1 mol / 10 ⁶ g, whitening is observed in the molding due to the influence of precipitated particles due to the catalyst residue, and the transparency is impaired. Conversely, if the amount is less than 0.6 / 10 ⁶ g, not only the transesterification reaction becomes insufficient, but also the subsequent polymerization reaction becomes slow, which is not preferable.

Further, a phosphorus compound is added in order to deactivate the transesterification catalyst, and the amount of the phosphorus compound (molar ratio) is 0.7 to 0.7% of the total amount of the cobalt compound and the manganese compound. It needs to be in the range of 1.5. When the molar ratio is less than 0.7, the transesterification catalyst is not completely deactivated, and the thermal stability is poor, which causes disadvantages that the polymer is colored or the physical properties at the time of molding are deteriorated. Conversely, if it exceeds 1.5, thermal stability is not preferred.

The manganese compound used in the present invention can be used as an oxide, chloride, carbonate, or carboxylate. Particularly, acetate, that is, manganese acetate is preferred.

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

As the polymerization reaction catalyst, it is preferable to use antimony trioxide as an antimony compound in terms of hue. If the amount of antimony trioxide is too small, the polymerization reactivity becomes low and the productivity is poor.On the other hand, if it is too large, the thermal stability is inferior and the physical properties during molding and the hue are deteriorated. The range is preferably from 3.0 mol / 10 ⁶ g.

It is preferable that all of the above-mentioned various catalysts are added during the period from the start of the transesterification reaction to the beginning of the transesterification reaction for the cobalt compound and the manganese compound.

On the other hand, the phosphorus compound can be added until the intrinsic viscosity reaches 0.3 after the transesterification reaction is substantially completed. Further, the antimony compound may be added simultaneously with the above-mentioned transesterification catalyst.

The intrinsic viscosity [η] e of the prepolymer obtained by melt polymerization preferably satisfies the following formula (6).

[0027]

[Equation 7] 0.40 ≦ [η] e ≦ 0.60 (6)

If the intrinsic viscosity is lower than 0.40, cracks or the like are caused when the chips are formed. If the intrinsic viscosity is higher than 0.60, the polymerization time is prolonged and the hue is deteriorated. The obtained polymer is subjected to solid-phase polymerization by a known method.

It is important to make the intrinsic viscosity [η] of the polymer after the solid-phase polymerization fall within the range of the following formula (5) for molding a PEN bottle.

[0030]

0.60 <[η] ≦ 0.80 (5)

If the intrinsic viscosity [η] is lower than 0.60, the polymer tends to crystallize during molding, causing not only whitening but also a low melt viscosity, resulting in poor blow moldability. On the other hand, if the intrinsic viscosity [η] is higher than 0.80, when the preform is molded at a normal molding temperature, the melt viscosity is too high and molding failure occurs. Therefore, if the molding temperature is increased to lower the melt viscosity, the viscosity of the molded product is reduced, and the molded product is easily crystallized, causing whitening and deterioration of hue.

The amount of acetaldehyde in the polymer is 5 pp
m or less. Above this, acetaldehyde elutes into the bottle filling, giving the contents an off-flavor.

It is preferable to carry out solid-phase polymerization in order to keep the intrinsic viscosity of the present polymer in the above range. Solid phase polymerization can be performed by a known method.

[0034]

The present invention will be described more specifically with reference to the following examples. The parts in the examples mean "parts by weight".

(1) Intrinsic viscosity ([η]): Measured at 35 ° C. as a mixed solvent of tetrachloroethane: phenol = 4: 6.

(2) Col-L, b (hue): The polymer was 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 this was blow-stretched and the internal volume was increased. The bottle was 1.5 liters and had a body thickness of 300 μm. The haze of the body of the bottle was measured with a turbidity meter manufactured by Nippon Denshoku Industries Co., Ltd.

(4) Acetaldehyde amount: The sample was freeze-pulverized and measured by HS-GC (manufactured by Hitachi, Ltd.).

[Example 1] 100 parts of 2,6-naphthalenedicarboxylic acid dimethyl ester and 51 parts of ethylene glycol (abbreviated as EG) were mixed with 0.1 part of cobalt acetate tetrahydrate.
Using 005 parts (0.2 mol / 10 ⁶ g) and 0.029 parts (1.2 mol / 10 ⁶ g) of manganese acetate tetrahydrate as a transesterification catalyst, 0.032 parts of a 1% EG 1% solution of antimony trioxide was used. (1.1 mol / 10 ⁶ g), followed by a transesterification reaction according to a conventional method, and 0.025 parts (1.8 mol / 10 ⁶ g) of trimethyl phosphate were added to terminate the transesterification reaction. Subsequently, a polycondensation reaction was carried out under a high temperature and a high vacuum by an ordinary method, and then a strand type chip was obtained. The intrinsic viscosity of the obtained polymer is 0.1.
50, and the polymerization time was 70 minutes. Intrinsic viscosity [η] of polymer obtained by solid-state polymerization of this polymer by a conventional method
Was 0.71. A preform obtained by injection molding using the polymer at a cylinder temperature of 300 ° C. was blow molded to obtain a 1.5 liter bottle. The bottle haze was 1.7%.

Example 2, Comparative Examples 1 to 11 The procedure was carried out except that the amounts and ratios of cobalt acetate tetrahydrate, manganese acetate tetrahydrate, trimethyl phosphate and antimony trioxide were changed as shown in Table 1. It carried out like Example 1. Table 1 also shows the obtained polymer quality and each evaluation result.

Comparative Example 12 Dimethyl Terephthalate 1
00 parts and 51 parts of ethylene glycol (abbreviated as EG) were mixed with 0.073 parts of manganese acetate tetrahydrate (3.0 mol / l).
0 with ⁶ g) as an ester exchange catalyst, EG1% solution 0.029 parts of antimony trioxide were transesterification according to a conventional method (1.0 mol / 10 ⁶ g) trimethyl phosphate 0.042 parts after addition ( 3.0 mol / 1
00 ⁶ g) was added and allowed to exit the transesterification reaction. Subsequently, a polycondensation reaction was carried out under a high temperature and a high vacuum by an ordinary method, and then a strand type chip was obtained. The intrinsic viscosity of the obtained polymer was 0.62, and the polymerization time was 70 minutes. The intrinsic viscosity [η] of the polymer obtained by subjecting this polymer to solid-state polymerization by a conventional method was 0.79. A preform obtained by injection molding using this polymer at a cylinder temperature of 275 ° C. was blow molded to obtain a 1.5 liter bottle. The bottle haze was 5.0%.

[0042]

[Table 1]

[0043]

EFFECT OF THE INVENTION The polyethylene naphthalenedicarboxylate of the present invention has a good hue, has little whitening (cloudiness) at the time of forming a bottle, has excellent transparency, and can be used for a bottle and has a high commercial value. sell.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-258394 (JP, A) JP-A-10-218979 (JP, A) JP-A 9-77859 (JP, A) (58) Survey Field (Int. Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (4)

(57) [Claims] 1. The method according to claim 1, wherein the cobalt compound, the manganese compound, the phosphorus compound and the antimony compound present in the polyethylene naphthalenedicarboxylate are represented by the following formulas (1) to (4):
At the same time, and the intrinsic viscosity [η] of the polymer satisfies the following formula (5). ## EQU1 ## 0.04 ≦ Co ≦ 2.4 mol (1) 0.6 ≦ Mn ≦ 2.1 mol (2) 0.7 ≦ P / (Co + Mn) ≦ 1.5 (3) 0.8 ≦ Sb ≦ 3.0 mol (4) (However, each metal element in the above formula indicates the number of mols per 10 ⁶ g of the acid component.) 0.60 <[η] ≦ 0.80 (5) ) 2. The polyethylene naphthalenedicarboxylate for a bottle according to claim 1, wherein the cobalt compound, manganese compound, phosphorus compound and antimony compound are compounds derived from a catalyst. 3. A method according to claim 1, wherein the cobalt compound, the manganese compound, the phosphorus compound and the antimony compound present in the polyethylene naphthalenedicarboxylate are represented by the following formulas (1) to (4).
At the same time, and the intrinsic viscosity of the polymer used for solid-state polymerization
[η] e is polyethylene naphthalenedicarboxylate for bottles satisfying the following formula (6). 0.04 ≦ Co ≦ 2.4 mol (1) 0.6 ≦ Mn ≦ 2.1 mol (2) 0.7 ≦ P / (Co + Mn) ≦ 1.5 (3) 0.8 ≦ Sb ≦ 3.0 mol (4) (where each metal element in the above formula represents the number of mols per 10 ⁶ g of the acid component.) 0.40 ≦ [η] e ≦ 0.60 ( 6) 4. The haze of the body when molded into a bottle is 2%.
The polyethylene naphthalenedicarboxylate for a bottle according to claim 1, which is: