JPH11158257A - Polyethylene naphthalenedicarboxylate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyethylene naphthalenedicarboxylate which has an improved hue, is excellent in clarity, and is suitable for producing packaging materials such as bottles and sheets. SOLUTION: This polyethylene naphthalenedicarboxylate is formed from an acid component mainly comprising a naphthalenedicarboxylic acid and a glycol component mainly comprising ethylene glycol, contains a cobalt compd., a manganese compd., a phosphorus compd., and an antimony compd. in amts., based on the acid component, satisfying the following relations: (1) Co<=30 mmol.%, (2) 10<=Mn$60 mmol.%, (3) 0.7<=P/(Mn+Co)<=1.5 (molar ratio), and (4) 5<=Sb<=40 mmol.% (provided Sb is the number of moles in terms of antimony trioxide), and further contains a dye.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene naphthalenedicarboxylate, and more particularly, to a polyethylene naphthalenedicarboxylate having an improved hue and excellent transparency and suitable for packaging materials such as bottles and sheets.

[0002]

2. Description of the Related Art Polyethylene naphthalenedicarboxylate has recently been used in bottles (containers) and sheet materials because of its superior physical properties such as heat resistance, gas barrier property, chemical resistance and the like as compared with polyethylene terephthalate. Many proposals have been made by blending with polyethylene terephthalate or using alone.

[0003] In particular, materials used for beverage bottles are strongly required to have excellent physical properties such as hue and transparency from the viewpoint of commercial value.

Polyethylene naphthalene dicarboxylate can be produced by a polymerization reaction using the same catalyst as polyethylene terephthalate. Particularly, when a germanium catalyst is used as a polycondensation catalyst, preferable ones can be obtained from the viewpoint of hue and crystallinity. it can.

JP-A-9-77859, Japanese Patent Application No. 9-77859
JP 20402 proposes polyethylene naphthalenedicarboxylate using a germanium catalyst.

However, germanium catalysts have problems in terms of cost and catalytic activity, and it has become necessary to use antimony compounds as polycondensation catalysts. Although the cost and the polymerization activity are improved by using an antimony compound as the polycondensation catalyst, a problem arises that the haze is increased at the time of bottle molding due to precipitated particles caused by the antimony catalyst.

[0007] To solve this problem, Japanese Patent Application No. 9-5163 is disclosed.
By limiting the specific catalyst type and amount in 6, a highly transparent polyethylene naphthalenedicarboxylate could be obtained, and the hue was also improved to some extent.

However, the polyethylene naphthalenedicarboxylate polymer has a large coloring due to its high melt viscosity depending on polycondensation conditions and molding conditions, and the hue is not always sufficient.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems. By limiting the kind and amount of the catalyst, the transparency of polyethylene naphthalenedicarboxylate is maintained while the hue is further improved. It is to provide an improved polyethylene naphthalenedicarboxylate.

[0010]

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, comprising a cobalt compound, a manganese compound, a phosphorus compound and an antimony compound, The following formula (1) for the component
A polyethylene naphthalenedicarboxylate having an improved hue, characterized in that it contains the dye in an amount satisfying (4) and further contains a dye. (1) Co ≦ 30 mmol% (2) 10 ≦ Mn ≦ 60 mmol% (3) 0.7 ≦ P / (Mn + Co) ≦ 1.5 (molar ratio) (4) 5 ≦ Sb ≦ 40 mmol% (however, , Sb is the number of moles as antimony trioxide)

The naphthalenedicarboxylic acid as the main acid component in the polyethylene naphthalenedicarboxylate of the present invention is 2,6-naphthalenedicarboxylic acid and / or
Or 2,7-naphthalenedicarboxylic acid. Mainly, it is at least 70 mol%, preferably at least 80 mol%, based on all acid components.

In the polyethylene naphthalenedicarboxylate of the present invention, other acid components can be copolymerized within a range of less than 30 mol% of the total acid components. As copolymerizable acid components, oxalic acid, malonic acid, succinic acid, adipic acid,
Aliphatic dicarboxylic acids such as sebacic acid and dodecane dicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, diphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ether dicarboxylic acid; cyclohexane dicarboxylic acid, decalin dicarboxylic acid Acids, alicyclic dicarboxylic acids such as teleralin dicarboxylic acid; oxyacids such as glycolic acid and p-oxybenzoic acid;

Ethylene glycol as a main glycol component in the polyethylene naphthalenedicarboxylate of the present invention must be present in an amount of 70 mol% or more based on the total diol component. Glycol, hexamethylene glycol, diethylene glycol, triethylene glycol, neopentyl glycol, cyclohexane dimethanol, bisphenol A and the like may be copolymerized.

When the acid component and / or the glycol component is copolymerized in an amount exceeding 30 mol%, the physical properties of polyethylene naphthalenedicarboxylate are inferior.

In the production of the polyethylene naphthalenedicarboxylate of the present invention, a lower alkyl ester of naphthalenedicarboxylic acid and ethylene glycol are used in a transesterification reaction to give a cobalt compound in an amount of 30 mmol% or less based on the total acid components and a manganese compound of 10 to 10 mol%. 60
Mmol is added as catalyst.

The addition of the cobalt compound has an effect of further improving the hue in addition to the catalytic effect of the transesterification reaction. When the addition amount of the cobalt compound exceeds 30 mmol% with respect to the acid component, the obtained polymer is less yellowed, but is grayish in hue.

When the amount of the manganese compound is less than 10 mmol% based on the total acid components, the transesterification reaction becomes insufficient, and the subsequent polymerization reaction and solid-state polymerization reaction rate decrease. If the manganese compound is added in an amount exceeding 60 mmol% based on the total acid components, the transparency of the molded product in a bottle or the like is inferior due to the effect of precipitated particles due to the catalyst residue.

Furthermore, it is necessary to add a phosphorus compound in order to deactivate the transesterification catalyst. It is necessary that the addition amount of the phosphorus compound is 0.7 to 1.5 mole times the total mole number of the cobalt compound and the manganese compound. If the addition amount is less than 0.7 mole times, the transesterification catalyst is not sufficiently deactivated, and there is a problem in terms of thermal stability and hue. If the amount exceeds 1.5 mole times, there is a problem in terms of thermal stability.

The cobalt compound and manganese compound used in the present invention can be used as oxides, chlorides, carbonates, acetates and carboxylate salts, and among them, acetate salts are preferred.

As the phosphorus compound, orthophosphoric acid, phosphoric acid ester, phosphoric acid triester and the like are used. Among them, trimethyl phosphate or at least one group is replaced with a hydroxyalkyl group or a hydroxy (polyalkylene glycol) group. Preferred are phosphoric acid esters.

As the polymerization catalyst, an antimony compound is used from the viewpoint of cost, but antimony trioxide is particularly preferable. The amount of the antimony compound to be added is 5 to 40 mmol% based on the acid component. If the amount is less than 5 mmol%, the polymerization reaction rate decreases, and the productivity is low, which is problematic. 4
If it exceeds 0 mmol%, the thermal stability is poor, so that the physical properties during molding and the hue deteriorate.

The above-mentioned cobalt compound, manganese compound, phosphorus compound and antimony compound are preferably added during a period from the start of the transesterification reaction to the beginning of the transesterification reaction.

The addition time of the antimony compound is not particularly limited as long as it is added up to the early stage of the polycondensation reaction, and the antimony compound may be added at the same time as the cobalt compound and the manganese compound, or may be added alone.

As the method of addition, all of the above-mentioned cobalt compound, manganese compound and antimony compound may be added after heating and mixing, or any two of them may be added after heating and mixing.

It is preferable to add the phosphorus compound after the transesterification reaction is substantially completed and before the intrinsic viscosity reaches 0.3.

On the other hand, in the present invention, a dye is added.
As the dye to be added, a blue dye and / or a purple dye are preferable. Among these dyes, anthraquinone-based organic dyes are preferred.

The anthraquinone-based organic dyes include 1,4
-Bis (2,4,6-trimethylanilino) -9,10
-Anthraquinone, 1-hydroxy-4-((3-hydroxymethyl) phenylanilino) -9,10-anthraquinone, 1,4,5,8-tetraamino-9,10-
Anthraquinone, 3-hydroxy-1- (4-methylphenylanilino) -9,10-anthraquinone, 1,4
-Diamino-9,10-anthraquinone and the like. Above all, 1,4-bis (2,4,6-trimethylanilino) -9,10-anthraquinone, 3-hydroxy-
1- (4-methylphenylanilino) -9,10-anthraquinone is preferred.

However, when the obtained polyethylene naphthalenedicarboxylate is used for a packaging material that comes into direct contact with foods such as beverages, the dye used may be limited.

The amount of the dye used is 0.1 to 1 with respect to polyethylene naphthalene dicarboxylate.
It is preferably 0 ppm. If the amount is less than 0.1 ppm, the coloring of the polyethylene naphthalenedicarboxylate polymer is not sufficient, and the effect of improving the hue is small.

The intrinsic viscosity of the obtained polyethylene naphthalenedicarboxylate is preferably from 0.6 to 0.8. When the polyethylene naphthalenedicarboxylate obtained when the intrinsic viscosity is less than 0.6 is molded into a bottle, crystallization proceeds easily and the resulting bottle is not only inferior in transparency but also has a low melt viscosity and is blow molded. Poor in terms of properties. When the ratio exceeds 0.8, the melt viscosity is high, so that it becomes difficult to perform injection molding of the bottle preform, the molding temperature must be increased, and the coloring of the polymer becomes undesirably large. In addition, aldehydes, which are decomposition products, are generated more frequently, and the taste of the beverage filled after the bottle is formed is disadvantageously deteriorated.

In order to solve such a problem, a method of increasing the intrinsic viscosity by solid-phase polymerization of a prepolymer melt-polycondensed is generally used. At that time, it is preferable that the intrinsic viscosity of the prepolymer is in the range of 0.4 to 0.6 in order not to impair the physical properties of the finally obtained polyethylene naphthalenedicarboxylate. When the intrinsic viscosity of the prepolymer is less than 0.4, when the polymer is formed into chips after the completion of the melt polycondensation reaction, cracked chips frequently occur,
This is not preferable because not only the shape uniformity is lost but the polymer quality after the solid-phase polymerization reaction varies but also the load on the solid-phase polymerization increases and the productivity decreases. If the intrinsic viscosity of the prepolymer exceeds 0.6, it is not preferable in terms of generation of aldehydes due to coloring and decomposition in the melt polycondensation step as described above.

The smaller the amount of aldehydes, the better. However, it is desirable that the content of the aldehydes is at least 20 ppm, preferably 10 ppm or less, from the viewpoint of taste of the beverage to be filled after the bottle is formed. If the aldehyde content is more than 20 ppm, the aldehyde is eluted during the filling of the bottle and the taste of the filling is spoiled, which is not preferable.

The bottle formed from the polyethylene naphthalenedicarboxylate thus obtained must have a body haze of 2% or less. This is a value when the thickness is 300 μm. If the haze exceeds 2%, the appearance is not preferable. Bottle thickness is usually 200μm ~ 500μ
m.

The polyethylene naphthalenedicarboxylate of the present invention may contain various additives such as an antioxidant, an ultraviolet absorber and an antistatic agent, if necessary.

[0035]

The present invention will be described in more detail with reference to the following examples. Various properties were measured as follows.

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

Color measurement: Z-10 manufactured by Nippon Denshoku Industries Co., Ltd.
It was measured using 01DP. However, the color of the melt-polymerized product was measured after crystallization treatment at 170 ° C. for 1 hour before measurement.

Haze: After drying the polymer at 160 ° C. for 5 hours, a preform of 55 g was molded at a molding temperature of 305 ° C. using an injection molding machine 100DM manufactured by Meiki Seisakusho, and this was blow-stretched and the inner volume was 1. 5 liters, body thickness 30
It was a 0 μ bottle. The body of this bottle was cut out and measured with a turbidity meter manufactured by Nippon Denshoku Industries Co., Ltd.

Amount of acetaldehyde: The sample was freeze-pulverized and measured by HS-GC manufactured by Hitachi, Ltd.

Example 1 100 parts by weight of 2,6-naphthalenedicarboxylic acid dimethyl ester and 51 parts by weight of ethylene glycol were used as a transesterification catalyst using 0.030 parts by weight (30 mmol%) of manganese acetate tetrahydrate. 0.0005 parts by weight of 1,4-bis (2,4,6-trimethyl) anthraquinone and 0.03 parts of antimony trioxide
2 parts by weight (27 mmol%) was added as a polycondensation catalyst and transesterification was carried out according to a conventional method, and 0.023 parts by weight (40 mmol%) of trimethyl phosphate was added to terminate the transesterification reaction.

Next, a polycondensation reaction was carried out at a high temperature under a high vacuum by a conventional method to obtain a strand-shaped chip-shaped polymer. The intrinsic viscosity of the obtained polymer was 0.50.

Subsequently, the above polymer was heated to 240 ° C. or less,
Solid phase polymerization was carried out by a conventional method under high temperature and high vacuum of 1.0 mmHg or less to obtain polyethylene naphthalenedicarboxylate having an intrinsic viscosity of 0.70. The obtained polymer was injection-molded at 305 ° C. and blow-stretched to obtain a 1.5-liter bottle. The haze of the obtained bottle was 1.1.

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 a transesterification reaction and then to a polycondensation reaction, whereupon 1,4-bis (2,4,6- A polyethylene naphthalenedicarboxylate was obtained in the same manner as in Example 1 except that trimethyl) anthraquinone was not added. Although the transparency of the obtained polymer was maintained, it was inferior in hue.

Example 2 100 parts by weight of dimethyl 2,6-naphthalenedicarboxylate and 51 parts by weight of ethylene glycol were 0.010 parts by weight (10 mmol%) of cobalt acetate tetrahydrate and 0.1 part of manganese acetate tetrahydrate. 020 parts by weight (20 mmol%) as a transesterification catalyst, 0.0005 parts by weight of 1,4-bis (2,4,6-trimethyl) anthraquinone, 0.012 parts by weight of antimony trioxide as a polycondensation catalyst (10 mmol%) and transesterification was carried out according to a conventional method, and then 0.023 parts by weight (40 mmol%) of trimethyl phosphate was added to terminate the transesterification reaction. Next, after performing a polycondensation reaction according to a conventional method, the haze when the polymer obtained through the solid-state polymerization step was molded into a bottle was 1.2.

[Examples 3 to 5, Comparative examples 2 to 5] Cobalt acetate tetrahydrate, magnesium acetate tetrahydrate, trimethyl phosphate, antimony trioxide and dyes were as shown in the table. Thus, polyethylene naphthalenedicarboxylate was obtained. The quality of the obtained polymer and the results of haze measurement at the time of bottle molding are shown together in the table.

[0046]

[Table 1]

[0047]

The polyethylene naphthalenedicarboxylate of the present invention is excellent in hue and transparency, and when molded into bottles and sheets, commercially available bottles and sheets can be obtained.

Claims (7)

[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 manganese compound, a phosphorus compound and an antimony compound are represented by the following formula (1): (4) A polyethylene naphthalenedicarboxylate having an improved hue, characterized by containing an amount satisfying (4) and further containing a dye. (1) Co ≦ 30 mmol% (2) 10 ≦ Mn ≦ 60 mmol% (3) 0.7 ≦ P / (Mn + Co) ≦ 1.5 (molar ratio) (4) 5 ≦ Sb ≦ 40 mmol% (however, , Sb is the number of moles as antimony trioxide) 2. The polyethylene naphthalenedicarboxylate according to claim 1, wherein the dye is a blue dye and / or a purple dye. 3. The polyethylene naphthalenedicarboxylate according to claim 1, wherein the intrinsic viscosity of the polymer is 0.6 to 0.8. 4. The polyethylene naphthalenedicarboxylate according to claim 1, wherein the dye is an anthraquinone organic dye. 5. A dye content of 0.1 to 10 pp with respect to the polyethylene naphthalene dicarboxylate polymer.
2. The polyethylene naphthalenedicarboxylate according to claim 1, wherein m is in the range of m. 6. The polyethylene naphthalenedicarboxylate according to claim 1, produced by solid-state polymerization of a prepolymer having an intrinsic viscosity of 0.4 to 0.6. 7. The body haze when formed into a bottle is 2%.
2. The polyethylene naphthalenedicarboxylate according to claim 1, which is: