JP3445158B2 - Polyethylene naphthalenedicarboxylate and bottle - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to polyethylene naphthalene dicarboxylate, and more particularly to polyethylene naphthalene dicarboxylate which is excellent in hue, transparency and the like in which crystallinity is suppressed even when an antimony compound is used as a polycondensation catalyst. Regarding

[0002]

2. Description of the Related Art Polyethylene naphthalene dicarboxylate has a higher heat resistance than polyethylene terephthalate.
Since it has excellent basic physical properties such as gas barrier properties and chemical resistance, it is being used in bottles (containers) or sheet materials in recent years, and many proposals have been made by blending with polyethylene terephthalate or by using it alone. Above all, for use in beverage bottles, from the viewpoint of commercial value, excellent qualities of appearance such as hue and transparency are strongly required.

Polyethylene naphthalene dicarboxylate can be obtained by reacting with a catalyst similar to polyethylene terephthalate. When a germanium compound is used as a polycondensation catalyst, the hue and transparency are excellent, but the cost is high and the polymerization activity is high. There are also problems such as low.

On the other hand, when an antimony compound is used as a polycondensation catalyst, although there is no problem in terms of cost and polymerization activity, the precipitation of metal antimony and its nucleating agent effect lead to
When molding the obtained polymer into a bottle or sheet,
There are problems that the appearance such as transparency is deteriorated and that the hue such as blackening of the polymer due to precipitation of metal antimony is inferior.

Thus, the polyethylene naphthalene dicarboxylate polymer and the bottle formed by molding the polyethylene naphthalene dicarboxylate polymer were not always satisfactory in terms of appearance such as hue and transparency.

[0006]

The present invention has been made in view of the above problems, and defines the amount of antimony compound of polyethylene naphthalene dicarboxylate using an antimony compound as a polycondensation catalyst and the intrinsic viscosity of polyester. By doing so, polyethylene naphthalene dicarboxylate excellent in appearance such as hue and transparency,
In particular, it is to provide polyethylene naphthalene dicarboxylate that can be suitably used for bottle applications.

[0007]

That is, the present invention provides a polyethylene naphthalene dicarboxylate obtained by using an antimony compound as a polycondensation catalyst and having a crystallinity satisfying the following formula and being excellent in hue and transparency.

[0008]

[Equation 2]

[Wherein χc is the crystallinity, the Sb catalyst amount is the amount of the antimony compound added to the total acid components (value converted to the amount of antimony trioxide: mmol%), and IV is It is the intrinsic viscosity of the polymer. ].

The present invention will be described in more detail below.

The polyethylene naphthalene dicarboxylate of the present invention contains naphthalene dicarboxylic acid as a main acid component and ethylene glycol as a main diol component.

The naphthalenedicarboxylic acid as the main acid component in the present invention means 2,6-naphthalenedicarboxylic acid and its lower alkyl ester derivative, 2,7-
Naphthalenedicarboxylic acid and its lower alkyl ester derivatives. The term “mainly” means 70 mol% or more, preferably 80 mol% or more of the total dicarboxylic acid component.

Examples of components copolymerizable in the range of 30 mol% or less include oxalic acid, malonic acid, succinic acid, isophthalic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonedicarboxylic acid and diphenyletherdicarboxylic acid. Aromatic dicarboxylic acids; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, decalin dicarboxylic acid, and tereralin dicarboxylic acid; and oxy acids such as glycolic acid and p-oxybenzoic acid.

70 mol% or more of the diol component is composed of ethylene glycol, and within the range of 30 mol% or less, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, triethylene glycol, neopentyl glycol, cyclohexanedimethanol,
Bisphenol A or the like may be copolymerized.

30 mol% of acid component and glycol component
When copolymerized in excess of 10%, polyethylene naphthalene dicarboxylate has inherent physical properties such as gas barrier property,
Inferior heat resistance.

In the present invention, the diol component present as a copolymerization component in the polymer is diethylene glycol, but the copolymerization amount thereof is preferably 3.0% by weight or less based on the total amount of the polymer. When the diol component is copolymerized in the polyester in an amount of more than 3.0% by weight, the heat resistance and mechanical strength of the obtained polyester will be significantly reduced, and uneven thickness tends to occur during extrusion molding or blow molding. It is not preferable because the range of molding conditions becomes narrow.

In the present invention, it is necessary to use an antimony compound as a polycondensation catalyst. Examples of the antimony compound include antimony oxide, antimony acetate, and glycolate antimonate. Among them, antimony trioxide is preferably used.

The amount of antimony compound added is preferably in the range of 5 to 20 mmol% based on the total acid components in terms of antimony trioxide. If the added amount of the antimony compound is less than 5 mmol%, the polymerization activity is low,
Not only is it unfavorable from the economical point of view that the polycondensation time is long and the productivity is lowered, but also the quality is inferior such that the side reaction product is increased and the hue is deteriorated due to the increase of the polycondensation time. Addition amount of antimony compound is 2
When it exceeds 0 mmol%, the crystallinity increases due to the crystal nucleating agent effect of the precipitated metal antimony, which impairs the appearance of the obtained polyester molded article and accelerates the decomposition reaction at the time of remelting at the time of molding, thereby acetaldehyde. It is not preferable because undesired side-reaction products such as increase.

The crystallinity of the polyethylene naphthalene dicarboxylate polymer of the present invention must satisfy the following formula 1.

[0020]

[Equation 3]

[Wherein χc is the crystallinity, the Sb catalyst amount is the amount of the antimony compound added to the total acid component (value converted to the amount of antimony trioxide: mmol%), and IV is It is the intrinsic viscosity of the polymer. When the crystallinity of the polymer exceeds the range of the formula 1, the crystallinity becomes unnecessarily high, and it is necessary to raise the molding temperature due to the melting of the polymer at the time of molding, which deteriorates the hue and undesired products such as acetaldehyde. Is significantly increased. Further, in the case of molding without raising the molding temperature, the appearance of the molded product is deteriorated by the unmelted polymer and the transparency of the molded product obtained is deteriorated by the crystallization acceleration due to the nucleating agent effect. If the crystallinity of the polymer is below the range of Equation 1,
When molding polyethylene naphthalene dicarboxylate, a crystallization process is required once.

The polyethylene naphthalene dicarboxylate of the present invention preferably has an intrinsic viscosity in the range of 0.4 to 0.8.

When the intrinsic viscosity of the polyester is less than 0.4, it causes deterioration of mechanical strength and the like when formed into a molded product, which is not preferable. Intrinsic viscosity of polyester is 0.8
If it exceeds, not only the coloring at the time of polymerization and the increase of side reaction products become remarkable, but also the deterioration of the polymer is promoted due to the shear heat generation due to the high melt viscosity when forming a molded product, which is not preferable. .

The polyethylene naphthalene dicarboxylate of the present invention, after the prepolymer is obtained by melt polymerization,
It is preferably produced by solid phase polymerization. In this case,
The difference in intrinsic viscosity (ΔIV) between the prepolymer used for solid-phase polymerization and the polymer after solid-phase polymerization is preferably 0.25 or less. When the difference between the intrinsic viscosity of the prepolymer and the intrinsic viscosity of the polymer after solid phase polymerization exceeds 0.25, the crystallinity of the solid phase polymer obtained by increasing the solid phase polymerization temperature or increasing the solid phase polymerization time increases. However, when polyethylene naphthalene dicarboxylate is used as a molded product, the appearance such as transparency is impaired, which is not preferable. In addition, the solid-phase polymerization time also becomes long, which is not preferable because of a problem that productivity is lowered.

The polyethylene naphthalene dicarboxylate polymer of the present invention preferably has a crystallinity of 42% or less. When the crystallinity of the polyester exceeds 42%, shearing heat is increased during molding, the hue is deteriorated, the degree of polymerization is lowered, and undesired products such as acetaldehyde are significantly increased, which is not preferable. Further, it is not preferable because problems such as deterioration of the appearance of the molded product due to the unmelted material and deterioration of the transparency of the molded product obtained due to crystallization acceleration due to the nucleating agent effect occur.

The color L value of the polyethylene naphthalene dicarboxylate of the present invention is preferably 65 or more. When the color L value of the polyester is less than 65, it is not preferable because it is inferior in hue when it is used as a molded product. In particular, when the addition amount of antimony compound as a polycondensation catalyst and cobalt compound as a color-matching agent is large, the resulting polymer is grayed, resulting in a large decrease in the color L value, which is a product for beverage containers such as bottles. It is not preferable because the value decreases.

Polyethylene naphthalene dicarboxylate can be produced by either the transesterification method or the direct esterification method, but when it is produced by the transesterification method, a transesterification reaction catalyst is required.

The transesterification reaction catalyst is not particularly limited, and is generally used as a transesterification reaction catalyst for polyethylene terephthalate. Manganese compounds, calcium compounds, magnesium compounds, titanium compounds, zinc compounds, sodium compounds, potassium compounds, cerium. Examples thereof include compounds and lithium compounds.
Further, a cobalt compound may be contained as a transesterification reaction catalyst which also acts as a color adjusting agent.

The polyethylene naphthalene dicarboxylate produced by the transesterification method and / or the direct esterification method preferably contains a phosphorus compound as a stabilizer.

As the phosphorus compound, orthophosphoric acid, phosphorous acid,
At least one selected from phosphoric acid esters, phosphoric acid triesters and the like can be used, but orthophosphoric acid and phosphorous acid are preferably used from the viewpoint of transparency.

The addition amount of the phosphorus compound varies depending on the production method, but it is preferable to add it so that the following residual amount is obtained.

When the polyethylene naphthalene dicarboxylate polymer is produced by the transesterification method, the residual amount of the phosphorus compound is 0.
It is preferable to add it in an amount of 7 to 2.0 mol times. When the content of the phosphorus compound is less than 0.7 mole times, the transesterification reaction catalyst cannot be sufficiently deactivated, and the obtained polyethylene naphthalene dicarboxylate polymer is inferior in thermal stability and hue, which is preferable. Absent. Further, even when the content of the phosphorus compound exceeds 2.0 mol times, it is not preferable because it is inferior in terms of thermal stability and hue.

On the other hand, when the polyethylene naphthalene dicarboxylate polymer is produced by the direct esterification method, it is not necessary to deactivate the catalyst because a transesterification reaction catalyst is not used as in the case of the above-mentioned transesterification method. It is preferable to add the phosphorus compound as an agent so that the residual amount thereof is in the range of 5 to 100 mmol% with respect to the total acid component. When the content of the phosphorus compound is less than 5 mmol% or more than 100 mmol% with respect to the total acid components, the resulting polyethylene naphthalene dicarboxylate polymer is inferior in thermal stability and hue, which is not preferable.

The acetaldehyde content of polyethylene naphthalene dicarboxylate is preferably 8 ppm or less. When the content of acetaldehyde in the polyethylene naphthalene dicarboxylate polymer exceeds 8 ppm, when it is used as a molded product for packaging foodstuffs such as bottles, it is inferior in flavor property, which is not preferable.

When the polyethylene naphthalene dicarboxylate obtained according to the present invention is molded into a bottle, it is preferable that the body haze is 3% or less. Body haze is 3%
If it exceeds, the transparency is lowered and the appearance as a product is inferior, which is not preferable. The haze of the bottle is a value at 300 μm, although the body thickness of the bottle varies depending on its capacity and use.

The polyethylene naphthalene dicarboxylate of the present invention may optionally contain an antioxidant, an ultraviolet absorber,
Various additives such as antistatic agents, dyes and pigments may be contained.

[0037]

The present invention will be described in more detail with reference to the following examples. Moreover, various characteristics were measured as follows.

Intrinsic viscosity: Calculated from solution viscosity measured at 35 ° C. using a mixed solvent of phenol / tetrachloroethane = 6/4 (weight ratio).

Crystallinity: Determined by measuring the specific gravity of the polymer.

Color L: The polymer was measured using Z-Σ80 manufactured by Nippon Denshoku Industries Co., Ltd.

Amount of diethylene glycol component: 2 g of the polymer was decomposed with 10 ml of hydrazine and measured by GC manufactured by Hitachi.

Haze: After the polymer is dried at 160 ° C. for 5 hours, 55 g of a preform is molded at a molding temperature of 305 ° C. using an injection molding machine 100DM manufactured by Meiki Seisakusho Co., Ltd., and blow-stretched. A bottle having a volume of 1.55 liters and a body thickness of 300 μm was used. The body of this bottle was cut out and measured with a turbidimeter manufactured by Nippon Denshoku Industries Co., Ltd.

Example 1 100 parts by weight of 2,6-naphthalenedicarboxylic acid dimethyl ester and 51 parts by weight of ethylene glycol were esterified by a conventional method in the presence of 0.030 parts by weight of manganese acetate tetrahydrate (30 mmol%). An exchange reaction was carried out, and 20 minutes after distilling methanol, 0.012 (10 mmol%) of antimony trioxide was added, and 0.020 part by weight (50 mmol%) of orthophosphoric acid was added before the completion of the transesterification reaction. Then, a polycondensation reaction was performed at 295 ° C. under a high vacuum of 1 mmHg or less to obtain a polyethylene naphthalene dicarboxylate prepolymer having an intrinsic viscosity of 0.47. Further, this prepolymer was subjected to solid phase polymerization by a conventional method to obtain a polymer having an intrinsic viscosity of 0.65 and a crystallinity of 38%. The degree of DEG copolymerization of the obtained polymer is 1.5.
%, Color L value = 79, the amount of acetaldehyde was 2 ppm, and the body haze was 1.2% when the polymer was molded into a bottle.

Example 2 100 parts by weight of 2,6-naphthalenedicarboxylic acid dimethyl ester, 51 parts by weight of ethylene glycol, 0.010 parts by weight of cobalt acetate tetrahydrate (10 mmol%), and 0.030 parts by weight of manganese acetate. Transesterification reaction by the conventional method in the presence of 20 parts by mass (30 mmol%), 0.012 parts by weight of antimony trioxide (10 mmol%) was added 20 minutes after methanol was distilled off, and orthophosphoric acid was added in an amount of 0. 020 parts by weight (50 mmol%) were added. Then, a polycondensation reaction was performed at 295 ° C. under high vacuum to obtain a polyethylene naphthalene dicarboxylate prepolymer having an intrinsic viscosity of 0.47. Further, this prepolymer was subjected to solid phase polymerization to obtain a polymer having an intrinsic viscosity of 0.68 and a crystallinity of 39%. Table 1 shows the physical properties of the obtained polymer and the haze of the body portion after molding the bottle.

Example 3 100 parts by weight of 2,6-naphthalenedicarboxylic acid and 57 parts by weight of ethylene glycol were subjected to an esterification reaction by a conventional method, and then 0.012 parts by weight of cobalt acetate tetrahydrate (10 mmol%) ), Orthophosphoric acid 0.
007 parts by weight (15 mmol%) and 0.013 parts by weight of antimony trioxide (10 mmol%) were added to obtain 295
Polycondensation reaction was carried out under high vacuum at 0 ° C. to obtain a polyethylene naphthalene dicarboxylate prepolymer having an intrinsic viscosity of 0.048. This prepolymer was further solid-phase polymerized to obtain a polymer having an intrinsic viscosity of 0.65 and a crystallinity of 37%. The physical properties of the obtained polymer and the haze of the body when molded into a bottle are as shown in Table 1.

Comparative Example 1 100 parts by weight of 2,6-naphthalenedicarboxylic acid dimethyl ester and 51 parts by weight of ethylene glycol were subjected to transesterification reaction in the presence of 0.030 parts by weight (30 mmol%) of manganese acetate tetrahydrate. Then, 20 minutes after distilling methanol, 0.012 parts by weight (10 mmol%) of antimony acetate was added, and 0.020 parts by weight (50 mmol%) of orthophosphoric acid was added before the reaction to give an intrinsic viscosity of 0.45. A polyethylene naphthalene dicarboxylate prepolymer was obtained. This prepolymer was subjected to solid phase polymerization by a conventional method to obtain a polymer having an intrinsic viscosity of 0.71 and a crystallinity of 43%. The physical properties and the like of the obtained polymer are as shown in Table 1 and were inferior in terms of hue and transparency.

[Comparative Example 2] 100 parts by weight of 2,6-naphthalenedicarboxylic acid and 57 parts by weight of ethylene glycol were esterified by a conventional method, and then 0.012 parts by weight of cobalt acetate tetrahydrate (10 mmol%) ), Orthophosphoric acid 0.
005 parts by weight (10 mmol%) and antimony trioxide 0.036 parts by weight (27 mmol%) were added, and then polycondensation reaction was carried out at 295 ° C. under high vacuum to obtain an intrinsic viscosity of 0.65.
A polymer with a crystallinity of 41% was obtained. The physical properties of the obtained polymer and the haze of the body after molding the bottle were as shown in Table 1.

Example 4 100 parts by weight of 2,6-naphthalenedicarboxylic acid dimethyl ester and 51 parts by weight of ethylene glycol were esterified by a conventional method in the presence of 0.030 parts by weight of manganese acetate tetrahydrate (30 mmol%). An exchange reaction was carried out, and 20 minutes after distilling methanol, 0.012 (10 mmol%) of antimony trioxide was added, and 0.020 part by weight (50 mmol%) of orthophosphoric acid was added before the completion of the transesterification reaction. Then, a polycondensation reaction was performed at 295 ° C. under a high vacuum of 1 mmHg or less to obtain a polyethylene naphthalene dicarboxylate polymer having an intrinsic viscosity of 0.63. The obtained polymer was crystallized at 170 ° C. for 8 hours in a nitrogen atmosphere, and then further crystallized at 230 ° C. for 24 hours,
A polymer having an intrinsic viscosity of 0.63 and a crystallinity of 39% was obtained. The physical properties of the polymer obtained and the haze of the body during bottle molding are as shown in Table 1.

[Examples 5-7, Comparative Examples 3-5] 2,6-
100 parts by weight of naphthalenedicarboxylic acid dimethyl ester and 51 parts by weight of ethylene glycol are subjected to transesterification reaction in the presence of 0.030 parts by weight (30 mmol%) of manganese acetate tetrahydrate, and antimony trioxide is added after 20 minutes of methanol distillation. Then, before completion of the reaction, 0.020 parts by weight of orthophosphoric acid (50 mmol%) was added, and then a polycondensation reaction was performed at 295 ° C. under high vacuum to obtain a polyethylene naphthalene dicarboxylate prepolymer. The obtained prepolymer was further solid-phase polymerized to obtain a polymer having an intrinsic viscosity shown in Table 1. The physical properties of the obtained polymer and the haze of the body when molded into a bottle are as shown in Table 1.

[0050]

[Table 1]

[0051]

The polyethylene naphthalene dicarboxylate of the present invention is excellent in appearance such as transparency and hue,
It is a polymer with high commercial value in sheet applications.

Continuation of front page (56) Reference JP-A-8-311178 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (9)

(57) [Claims] 1. A polyethylene naphthalene dicarboxylate obtained by using an antimony compound as a polycondensation catalyst and having a crystallinity satisfying the following formula and having excellent hue and transparency. [Equation 1] [Where χc is the crystallinity, the Sb catalyst amount is the amount of the antimony compound added to the total acid components (value converted to the amount of antimony trioxide: mmol%), and IV is the intrinsic property of the polymer. Viscosity. ] 2. The polyethylene naphthalene dicarboxylate according to claim 1, wherein the antimony compound is in the range of 5 to 20 mmol% in terms of antimony trioxide with respect to the total acid component. 3. The polyethylene naphthalene dicarboxylate according to claim 1, which has an intrinsic viscosity of 0.4 to 0.8. 4. The polyethylene naphthalene according to claim 1, wherein the intrinsic viscosity difference (ΔIV) between the prepolymer obtained by solid phase polymerization and used in the solid phase polymerization and the polymer obtained by solid phase polymerization is 0.25 or less. Dicarboxylate. 5. The polyethylene naphthalene dicarboxylate according to claim 1, which has a crystallinity of 42% or less. 6. The polyethylene naphthalene dicarboxylate according to claim 1, which has a color L value of 65 or more. 7. The polyethylene naphthalene dicarboxylate according to claim 1, wherein the diethylene glycol component present as a copolymerization component in the polymer is 3.0% by weight or less. 8. The polyethylene naphthalene dicarboxylate according to claim 1, which has an acetaldehyde content of 8 ppm or less. 9. A bottle which is molded from the polyethylene naphthalene dicarboxylate according to claim 1 and has a body haze of 3% or less and which is excellent in hue and transparency.