JP3390675B2 - Polyethylene naphthalate resin for bottles - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyethylene naphthalate (hereinafter abbreviated as PEN) resin, and more specifically, it is a PEN suitable as a material for bottles which has little yellowing when dried at high temperature and has a good hue. TECHNICAL FIELD The present invention relates to a resin and a manufacturing method thereof.

[0002]

2. Description of the Related Art PEN resin is superior to polyethylene terephthalate (hereinafter abbreviated as PET) resin in basic physical properties such as heat resistance, gas barrier property and chemical resistance. It is useful as a packaging material for bottles (containers), sheets, films, etc., and many proposals have been made. Among packaging materials, resins used for bottles such as juice and cosmetics are strongly required to have excellent hue from the viewpoint of commercial value. PEN resin can be basically produced by the same catalyst system as in the case of PET resin, but as a polymerization catalyst,
The use of germanium dioxide makes it possible to produce PEN having a good hue, and many proposals have been made so far (Japanese Patent Laid-Open No. 7-1
09340, JP-A-8-92362, JP-A-9-77859).

A method of manufacturing a bottle using PEN resin can also be carried out in the same manner as PET. For example, after drying the resin, supply it to the injection molding machine,
There is a method of producing a preform and then blow-molding the same, or a method of supplying a dried resin to an extruder and blow-molding the extruded preform. However, the PEN resin requires a higher temperature for drying the resin than the PET resin. Therefore, there is a problem that the resin turns yellow when dried at a high temperature in the air with a hopper dryer or the like used in a general molding maker. In order to solve this problem, there is a method of drying the resin in a vacuum or in a nitrogen atmosphere,
Expensive equipment and utilities are required.

As an improvement from the resin side, in the case of PET, it has been proposed to improve the thermal stability by adding a transesterification catalyst and a phosphorus compound in an equimolar amount or more (saturated polyester by Kazuo Yuki, edited by Kazuo Yuki). The resin handbook, Nikkan Kogyo Shimbun (1989)), and PEN have almost the same proposals (JP-A-8-92362, JP-A-9-77859, etc.). However, the yellowing of the resin when dried at high temperature in air cannot be prevented only by adding the transesterification catalyst and the phosphorus compound in an equimolar amount or more.

The inventors of the present invention have earnestly studied the prevention of yellowing of PEN resin when dried at high temperature in air, and as a result, a specific amount of a transesterification catalyst was added and a germanium compound as a polymerization catalyst was added. The present inventors have found that by containing a specific amount, a PEN resin suitable for a material of a bottle which has less yellowing when dried at a high temperature in air and has a good hue can be obtained, and arrived at the present invention.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION That is, the first aspect of the present invention is a polyester containing naphthalenedicarboxylic acid as a main acid component and ethylene glycol as a main glycol component, wherein a calcium compound, a magnesium compound, a phosphorus compound and a germanium compound are A polyethylene naphthalate resin for bottles, characterized in that it contains an amount that simultaneously satisfies the following formulas (1) to (3). 2.0 ≦ Mg + Ca ≦ 6.0 mol (1) 0 <Ge ≦ 0.5 mol (2) 0.8 ≦ P / (Ca + Mg) ≦ 1.5 (3) (However, each metal element in the above formulas Indicates the number of moles per 10 ⁶ g of resin.)

The present invention will be described below. The term "mainly" as used herein means that it exceeds 70 mol%, preferably exceeds 80 mol%. Therefore, less than 30 mol% of other components may be included as a copolymer or mixture.

In the present invention, "naphthalenedicarboxylic acid" means, for example, 2,6-naphthalenedicarboxylic acid,
The main target is 2,7-naphthalenedicarboxylic acid and its ester-forming derivatives, but some of them (30 mol%
Other than dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid and other dicarboxylic acids; terephthalic acid,
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 Alicyclic dicarboxylic acids such as hexahydroterephthalic acid, decalin dicarboxylic acid, tetralin dicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; and oxy acids such as glycolic acid and P-oxybenzoic acid. Examples of the ester-forming derivative of the acid component include lower alkyl ester, phenyl ester, acid anhydride and the like.

Further, the "glycol component" is mainly intended for ethylene glycol, but a part (less than 30 mol%) thereof is other glycol such as tetramethylene glycol, propylene glycol, 1,3-butanediol, neo. Aliphatic diols such as pentyl glycol, cyclohexanedimethanol, alicyclic diols such as tricyclodecane dimethylol, aromatic diols such as bishydroxyethoxybisphenol A, bishydroxyethoxybisphenol S, and bishydroxyethoxytetrabromobisphenol A. It may be replaced by an alkylene glycol adduct of

Further, in the PEN resin of the present invention, a polycarboxylic acid having a functionality of 3 or more or a polyhydroxy compound such as tri-functional compound is added in an amount in a substantially linear range, for example, an amount of 2 mol% or less based on all acid components. The thing which copolymerized meritic acid, pentaerythritol, etc. is also included.

The PEN resin of the present invention is produced by a transesterification method. In the transesterification method, a lower alkyl ester of a dicarboxylic acid component and a glycol component are transesterified in the presence of a transesterification catalyst, and this is heated under reduced pressure in the presence of a polycondensation catalyst to remove an excess glycol component. It is a method of polymerizing by doing so.

Sodium compounds, potassium compounds, magnesium compounds, calcium compounds, manganese compounds, zinc compounds and the like are known as those used as transesterification catalysts in the production of conventional polyesters. However, the transparency, which is the object of the present invention,
In addition, there is no known example in which the type of catalyst and the amount added are examined for the purpose of improving heat resistance, particularly yellowing during high-temperature drying in air.

As a result of the study by the present inventors, it was found that a magnesium compound and a calcium compound are the most suitable as a transesterification catalyst used for producing a polyethylene naphthalate resin for bottles. The catalytic activity of sodium compounds and potassium compounds is too low, and the transesterification reaction is difficult to proceed. When manganese compounds and zinc compounds are used, transesterification catalysts and equimolar or more phosphorus compounds are added to improve thermal stability. However, when it is dried at a high temperature in the air, the yellowing becomes large.

The reasons why magnesium compounds and calcium compounds are excellent are considered as follows. That is, the catalytic activity of the manganese compound and the zinc compound was too high, and the catalyst was not completely deactivated even when the transesterification catalyst and the phosphorus compound in the equimolar amount or more were added. Therefore, the catalyst was dried in air at a high temperature. While the yellowing of time increases,
Since magnesium compounds and calcium compounds have an appropriate catalytic activity, addition of a transesterification catalyst and a phosphorus compound in an equimolar amount or more completely deactivates the catalyst,
It is considered that yellowing is small when dried at high temperature in air.

The content of the magnesium compound or the calcium compound in the PEN resin of the present invention is 2.10 as the magnesium element or the calcium element per 10 ⁶ g of the resin.
It is 0 mol or more and 6.0 mol or less. Further, the magnesium compound and the calcium compound may be contained at the same time, and in this case, the total content of the magnesium element and the calcium element is 2.0 mol or more per 10 ⁶ g of the resin,
It becomes 6.0 mol or less. If the content is less than 2.0 mol, the transesterification reaction does not proceed sufficiently and a resin cannot be obtained. On the other hand, if it exceeds 6.0 mol, yellowing becomes large when the resin is dried in air at a high temperature.

The magnesium compound and calcium compound used in the present invention are oxides, carbonates, carboxylates and the like, and are not particularly limited, but acetates, that is, magnesium acetate and calcium acetate are particularly preferable.

The ratio (molar ratio) of the phosphorus compound contained in the PEN resin of the present invention to the transesterification catalyst is 0.8 or more and 1.5 or less as elemental phosphorus. When a plurality of compounds are added as a transesterification catalyst, take the ratio with the total of all the added amounts. When this molar ratio is less than 0.8,
The transesterification catalyst is not completely deactivated, the thermal stability is deteriorated, the resin is colored, and the physical properties of the molded product are deteriorated. On the other hand, if it exceeds 1.5, the thermal stability of the resin is poor, which is not preferable.

The type of phosphorus compound used in the present invention is not particularly limited, and examples thereof include trimethyl phosphate (trimethyl phosphate), triethyl phosphate triethyl phosphate), and triphenyl phosphate (triphenyl phosphate).

Further, the content of the germanium compound in the PEN resin of the present invention is the same as that of the germanium element in the resin 10.
^It is more than 0 mol and 0.5 mol or less per ⁶ g. When it is 0 mol, the polycondensation reaction does not proceed, and when it exceeds the specified amount , yellowing becomes large when the resin is dried in air at a high temperature. The germanium compound used in the present invention is not particularly limited, but germanium dioxide is particularly preferable.

The polyester resin of the present invention may contain a cobalt compound or the like in order to improve the color tone. However, some of these have catalytic activity in the transesterification reaction or polycondensation reaction of polyester, and in the case of such a compound, the content is preferably as low as possible. For example, in the case of a cobalt compound, its content is 0.05 mol or more per 10 ⁶ g of resin as a cobalt element,
It is preferably 0.4 mol or less. When adding these compounds, the content (molar ratio) of the phosphorus compound, relative to the total content of the transesterification catalyst and these compounds,
The phosphorus element is preferably 0.8 or more and 1.5 or less.

Further, the polyethylene naphthalate resin of the present invention may contain other polyesters, other resins, or various additives as required. For example, P
Polyesters such as ET, ammonium salts such as hydroxytetraethylammonium for preventing by-products such as diethylene glycol, inorganic lubricants and organic lubricants for improving the slipperiness of molded articles, antioxidants, antistatic agents, Weathering agents and the like can be mentioned.

If necessary, the polyethylene naphthalate resin of the present invention may be crystallized by heating in a vacuum or under a nitrogen atmosphere by a known method, and further solid-phase polymerized.

The change in color b value Δb when the polyethylene naphthalate resin of the present invention is heated in air at 160 ° C. for 8 hours is preferably 3 or less. If Δb exceeds 3, yellowing is large and a molded product having a good hue cannot be manufactured.

The bottle resin of the present invention can be made into a bottle by a known method as in the case of PET resin. For example, as described in (Kazuo Yuki, Handbook of Saturated Polyester Resin, Nikkan Kogyo Shimbun (1989)), a dried resin is supplied to an extruder,
There are a method of blow-molding the extruded preform, and a method of supplying a dried resin to an injection molding machine to manufacture a preform and then blow-molding this.

The bottle resin of the present invention is excellent in transparency, hardly yellows even when dried at high temperature, and also has gas barrier properties. Therefore, it can be used not only as a material for bottle containers but also as a film or sheet.

Next, a method for producing the bottle resin of the present invention will be described. First, a lower alkyl ester of naphthalenedicarboxylic acid (dimethylnaphthalenedicarboxylic acid or the like), ethylene glycol, and a calcium compound and / or magnesium compound as an ester exchange catalyst are added as raw materials.

The calcium compounds and magnesium compounds used are those mentioned above as examples. At this time, the amount of the transesterification catalyst added was 2.0 per 10 ⁶ g of the resin.
It is important that the amount is from mol to 6.0 mol. When the amount of the transesterification catalyst added is below the lower limit, the reaction does not proceed or becomes extremely slow. If the amount added exceeds the upper limit, yellowing will increase when the resulting resin is dried in air at high temperature.

After completion of the transesterification reaction, a phosphorus compound and a germanium compound are added. Examples of the phosphorus compound include those described above. It is necessary to add a specific amount of the phosphorus compound to the added amount of the transesterification catalyst, and a ratio of 1.0 to 1.9 as a phosphorus element to the added amount of the transesterification catalyst. (Molar ratio) must be added. If the addition amount of the phosphorus compound is small, the transesterification catalyst will not be completely deactivated, the thermal stability will deteriorate, the resin will be colored, and the physical properties of the molded product will deteriorate. On the other hand, if the amount is too large, the thermal stability of the resin is poor, which is not preferable.

After adding the phosphorus compound and the germanium compound, the pressure inside the reaction system is temporarily reduced to carry out the polycondensation reaction. Note that, as described above, in the present invention, it is possible to appropriately add other additives and the like.

[0030]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The measurement and evaluation methods are shown below.

(1) Intrinsic viscosity (IV) Resin: phenol / tetrachloroethane = 60/40
It was dissolved in a mixed solvent (weight ratio) and measured at 20 ° C.

(2) 1 g of the contained elemental analysis resin pellets was ashed (wet ashing), diluted with water, and then boiled to remove nitric acid gas. Then, dilute with water to a fixed volume, and use ICP emission spectroscopy analyzer SPS1500VR
(Seiko Electronics Co., Ltd.) identified and quantified the contained elements.

(3) Color tone change due to high temperature heating in air 30 g of resin pellets was placed in a precision thermostat (fine oven) DH-62 type, and 160 ° C. × 8 in an air atmosphere.
After heating for an hour, SM color computer SM-4-2
The color b value (yellowness) was measured by (Suga Test Instruments Co., Ltd.), and the difference Δb from the color b value of the resin pellet before heating was determined.

(4) Bottle-tone resin pellets were placed in a hopper dryer and dried at 160 ° C. for 12 hours while circulating dry air. This resin was supplied to an injection molding machine to form a preform, which was blow-molded into a bottle having an internal volume of 1.5 liters. The color tone of this bottle was visually evaluated. ○: Good, ×: Colored in yellow, defective

Example 1 A stainless autoclave was charged with 244 parts by weight of 2,6-dimethylnaphthalate and 137 parts by weight of ethylene glycol, and then 0.11 part by weight of calcium acetate monohydrate (as calcium element) as an ester exchange catalyst. ,
Resin (2.6 mol per 10 ⁶ g) was added, and further 0.01 part by weight of cobalt acetate tetrahydrate (as cobalt element,
(0.2 mol per 10 ⁶ g of resin) was added to carry out transesterification reaction. After completion of the transesterification reaction, 0.002 parts by weight of hydroxytetraethylammonium and 0.11 parts by weight of trimethyl phosphate (resin 10 ⁶
Then, 3.2 mol per g) was added, and then 4.24 parts by weight of a 0.8 wt% aqueous solution of germanium dioxide as a polymerization catalyst (0.03 parts by weight as germanium dioxide (1.2 as germanium element per 10 ⁶ g of resin). Mol))
After addition, polycondensation reaction was performed at 290 ° C. under reduced pressure. Then, the pressure was returned to normal pressure, the content was extruded into a gut shape, cooled with water, and a chip-shaped PEN resin was obtained using a cutter. Further, this resin was heated in a vacuum at 160 ° C. for 8 hours for crystallization. The above-mentioned evaluation was carried out using this PEN resin.
Table 1 shows the evaluation results.

Examples 2 to 5 PEN resins were obtained in the same manner as in Example 1 except that the compositions of the catalyst and additives were changed as shown in Table 1. Table 1 shows the evaluation results.

Example 6 A stainless steel autoclave was charged with 232 parts by weight of 2,6-dimethylnaphthalate and 10 parts of dimethyl terephthalate.
1 part by weight, 137 parts by weight of ethylene glycol were charged, and then calcium acetate monohydrate as an ester exchange catalyst was added.
03 parts by weight (0.7 mol per 10 ⁶ g of resin as calcium element), 0.11 parts by weight of magnesium acetate tetrahydrate (2. 0 per 10 ⁶ g of resin as magnesium element).
1 mol) was added, and further cobalt acetate tetrahydrate 0.01
Parts by weight (0.1% per 10 ⁶ g of resin as cobalt element).
(2 mol) was added and transesterification was performed. After completion of the transesterification reaction, 0.002 part by weight of hydroxytetraethylammonium and 0.11 part by weight of trimethyl phosphate (3.2 mol per 10 ⁶ g of resin as a phosphorus element) were added, and then 0 of germanium dioxide was added as a polymerization catalyst. After addition of 4.24 parts by weight of a 0.8 wt% aqueous solution (0.03 parts by weight as germanium dioxide (1.2 mol per 10 ⁶ g of resin as germanium element)), 290 ° C.
The polycondensation reaction was performed under reduced pressure. Then, the pressure was returned to normal pressure, the content was extruded into a gut shape, cooled with water, and a chip-shaped PEN resin was obtained using a cutter. Further, this resin was heated in a vacuum at 160 ° C. for 8 hours for crystallization. The above-mentioned evaluation was carried out using this PEN resin. Table 1 shows the evaluation results.

Example 7 A PEN resin was obtained in the same manner as in Example 6 except that dimethyl terephthalate was replaced with dimethyl isophthalate. Table 1 shows the evaluation results.

Comparative Example 1 A stainless autoclave was charged with 244 parts by weight of 2,6-dimethylnaphthalate and 137 parts by weight of ethylene glycol, and then 0.09 parts by weight of manganese acetate tetrahydrate as an ester exchange catalyst (as elemental manganese). , 1.5 mol per 10 ⁶ g of resin) and 0.01 part by weight of cobalt acetate tetrahydrate (0.2 mol per 10 ⁶ g of resin as cobalt element) were added to carry out the transesterification reaction. It was After the completion of the transesterification reaction, 0.002 part by weight of hydroxytetraethylammonium and 0.06 part by weight of trimethyl phosphate (1.8 mol per 10 ⁶ g of the resin as a phosphorus element) were added, and then 0 of germanium dioxide was added as a polymerization catalyst. After adding 0.80% by weight aqueous solution 3.00 parts by weight (0.02 parts by weight as germanium dioxide (0.8 mol per 10 ⁶ g of resin as germanium element)), polycondensation reaction was carried out at 290 ° C. under reduced pressure. . Then, the pressure was returned to normal pressure, the content was extruded into a gut shape, cooled with water, and a chip-shaped PEN resin was obtained using a cutter. Further, this resin was heated in a vacuum at 160 ° C. for 8 hours for crystallization. The above-mentioned evaluation was carried out using this PEN resin.
Table 3 shows the evaluation results.

Comparative Examples 2 to 6 PEN resins were obtained in the same manner as in Example 1 except that the compositions of the catalyst and additives were changed as shown in Table 2. Table 3 shows the evaluation results.

Comparative Example 7 Calcium acetate monohydrate was added in an amount of 0.06 part by weight (so that the calcium element would be 1.4 mol with respect to 10 ⁶ g of resin), and trimethyl phosphate was added in an amount of 0. The reaction was carried out in the same manner as in Example 1 except that 06 parts by weight was added.
The transesterification reaction did not proceed sufficiently and a PEN resin could not be obtained.

Comparative Example 8 A reaction was performed in the same manner as in Example 1 except that germanium dioxide was not added, but the polycondensation reaction did not proceed,
The PEN resin could not be obtained.

Comparative Example 9 Reaction was carried out in the same manner as in Example 1 except that 0.05 part by weight of sodium acetate was added as the transesterification catalyst (so that the amount of sodium element was 2.5 mol with respect to 10 ⁶ g of the resin). However, the transesterification reaction did not proceed sufficiently and PE
N resin could not be obtained.

Comparative Example 10 A stainless steel autoclave was charged with 232 parts by weight of 2,6-dimethylnaphthalate and dimethyl terephthalate 10.
Parts by weight and 137 parts by weight of ethylene glycol, and then manganese acetate tetrahydrate 0.0 as a transesterification catalyst.
9 parts by weight (1.5 mol per 10 ⁶ g of resin as manganese element) were added, and further cobalt acetate tetrahydrate was added.
01 parts by weight (0.2 mol per 10 ⁶ g of resin as cobalt element) was added, and a transesterification reaction was carried out. After the completion of the transesterification reaction, 0.002 part by weight of hydroxytetraethylammonium and 0.06 part by weight of trimethyl phosphate (1.8 mol per 10 ⁶ g of the resin as a phosphorus element) were added, and then 0 of germanium dioxide was added as a polymerization catalyst. After addition of 3.00 parts by weight of a 0.8 wt% aqueous solution (0.02 parts by weight as germanium dioxide (0.8 moles per 10 ⁶ g of resin as germanium element)), 29
The polycondensation reaction was performed at 0 ° C. under reduced pressure. Then, the pressure was returned to normal pressure, the content was extruded into a gut shape, cooled with water, and a chip-shaped PEN resin was obtained using a cutter. Further, this resin was heated in a vacuum at 160 ° C. for 8 hours for crystallization. This PE
The above evaluation was performed using N resin. Table 3 shows the evaluation results.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

As is clear from the above results, when a compound other than a calcium compound or a magnesium compound is used as the transesterification catalyst, the resin turns yellow when dried at a high temperature in the air to deteriorate the color tone, or the ester. The exchange reaction does not proceed sufficiently and a resin cannot be obtained. [Comparative Examples 1, 10 and 9] Further, even when a calcium compound or a magnesium compound is used as a transesterification catalyst, if the amount is too small, the transesterification reaction does not proceed and a resin cannot be obtained. [Comparative Example 7] On the other hand, when the amount is too large, when the obtained resin is dried in air at a high temperature, it turns yellow and the color tone deteriorates, so that a bottle having a good color tone cannot be obtained. [Comparative Examples 2 and 3] Further, even if the phosphorus element in the resin is too little or too much with respect to the sum of the calcium element and the magnesium element, the obtained resin is dried in air at a high temperature. Then, it turns yellow and the color tone deteriorates, so that a bottle having a good color tone cannot be obtained.
[Comparative Examples 4 and 5] Further, even when the amount of the germanium compound used in the polycondensation reaction is too large, when the obtained resin is dried in air at a high temperature, it turns yellow and the color tone deteriorates, resulting in a good color tone. A bottle cannot be obtained [Comparative Example 6], and conversely, a resin cannot be obtained unless it is used. [Comparative Example 8]

[0049]

EFFECTS OF THE INVENTION The polyethylene naphthalate resin of the present invention has little yellowing when dried at high temperature, so it can be dried without using a special device such as a vacuum dryer, and a bottle having a good hue. Etc. can be manufactured at low cost.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-9-77859 (JP, A) JP-A-7-109340 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (2)

(57) [Claims] 1. A polyester comprising naphthalenedicarboxylic acid as a main acid component and ethylene glycol as a main glycol component, wherein the calcium compound, the magnesium compound, the phosphorus compound and the germanium compound simultaneously have the following formulas (1) to (3): A polyethylene naphthalate resin for bottles, which contains a filled amount. 2.0 ≦ Mg + Ca ≦ 6.0 mol (1) 0 <Ge ≦ 0.5 mol (2) 0.8 ≦ P / (Ca + Mg) ≦ 1.5 (3) (However, each metal element in the above formulas Indicates the number of moles per 10 ⁶ g of resin.) 2. The polyethylene naphthalate resin for bottles according to claim 1, wherein the change Δb in color b value when heated in air at 160 ° C. for 8 hours is 3 or less.