JPH07268085A - Polyester copolymer and bottle molded therefrom - Google Patents

Abstract

PURPOSE:To obtain a polyester copolymer useful as a material for bottles excellent in moldability, mechanical strengths, heat resistance, etc. CONSTITUTION:This copolymer is the one mainly consisting of terephthalic acid as part of the dicarboxylic acid component and ethylene glycol as part of the diol component, wherein the dicarboxylic acid component contains 8.0-15.0mol% 2,6-naphthalenedicarboxylic acid, the diol component contains 1.0-4.0mol% diethylene glycol, the content of antimony atoms is 150-350ppm, and the intrinsic viscosity is 0.70-1.50dl/g.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyester copolymer useful as a bottle material. For more details,
The present invention relates to a polyester copolymer having a high degree of polymerization, which can provide a bottle having excellent mechanical strength and heat resistance.

[0002]

2. Description of the Related Art Polyethylene terephthalate (hereinafter PE
A bottle made of T) can be easily molded, and as a container having excellent transparency and mechanical properties, seasoning, edible oil,
It is widely used in large quantities for food applications such as alcoholic drinks, carbonated drinks, beverages containing fruit juice, mineral water, and non-food applications such as detergents and cosmetics.

However, PET bottles have insufficient heat resistance as compared with glass bottles and PVC bottles.
In applications where the bottle is filled with drinking water and then heat-sterilized, there is a problem that the bottle is likely to be deformed when heat-sterilized.

A method for improving the heat resistance of the PET bottle is disclosed in, for example, Japanese Unexamined Patent Publication No. 5-255492.
A bottle made of a polyester copolymer containing a 6-naphthalenedicarboxylic acid component as a third component has been proposed. However, in the polyester copolymer containing the 2,6-naphthalenedicarboxylic acid component as the third component, the crystallinity is remarkably lowered as the molar ratio of the 2,6-naphthalenedicarboxylic acid is increased, and the bottle moldability is deteriorated. Therefore, in order to mold a normal bottle, it is necessary to manufacture a polyester copolymer having a high degree of polymerization by the solid phase polymerization method. However, since this polyester copolymer has low crystallinity, fusion between polymer particles is likely to occur during solid-phase polymerization, and when fusion occurs, it becomes difficult to continue the reaction, or the obtained polymer is A new problem has been clarified that the degree of polymerization becomes extremely uneven.

[0005]

The object of the present invention is to produce a polyester copolymer having a high degree of polymerization required for producing a bottle excellent in moldability, mechanical strength, heat resistance and the like. It is intended to improve the crystallization rate of the polyester copolymer in order to facilitate the phase polymerization.

[0006]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventors have produced a polyester copolymer containing a 2,6-naphthalenedicarboxylic acid component as a third component. In doing so, they found that the polycondensation reaction is carried out by using a specific amount of antimony compound as a catalyst, and reached the present invention.

That is, the present invention is a polyester copolymer comprising terephthalic acid as a dicarboxylic acid component and ethylene glycol as a diol component as a main component,
(1) 2,6-naphthalenedicarboxylic acid as a dicarboxylic acid component is 8.0 to 15.0 mol%, (2) diethylene glycol is 1.0 to 4.0 mol%, and (3) an antimony atom is contained. The amount is 150-350p
pm, (4) intrinsic viscosity of 0.70 to 1.50 dl / g, a polyester copolymer and a bottle comprising the same.

The method for producing the above polyester copolymer is a polyester copolymer containing terephthalic acid as the dicarboxylic acid component and ethylene glycol as the diol component as the main component, and (1) 2,6 as the dicarboxylic acid component. -Naphthalenedicarboxylic acid 8.0 to 15.0
Mol%, (2) 1.0 to 4.0 mol% of diethylene glycol as a diol component, (3) the content of antimony atoms is 150 to 350 ppm, and (4) the intrinsic viscosity is 0.5.
A preferred method is a solid state polymerization of a prepolymer having a concentration of 0 to 0.70 dl / g.

The present invention will be described in detail below. With respect to the main components of the polyester copolymer of the present invention, terephthalic acid and ethylene glycol, it is possible to use the raw materials used in known PET.

The proportion of 2,6-naphthalenedicarboxylic acid contained in the polyester copolymer of the present invention is 8.0 to 15.0 mol%, preferably 10.0 to 12.0 mol based on 100 of the dicarboxylic acid component. %. When it is less than 8.0 mol%, sufficient improvement in heat resistance is not observed, and 1
When it is more than 5.0 mol%, crystallization does not proceed even when an antimony catalyst is used, and solid-phase polymerization is difficult.
Since only a polyester having a low degree of polymerization can be obtained, the blow moldability of the bottle is significantly deteriorated.

The proportion of diethylene glycol (hereinafter referred to as DEG) contained in the polyester copolymer of the present invention is
It is 1.0 to 4.0 mol%, preferably 1.0 to 2.5 mol%, with the diol component as 100. Since DEG is produced as a by-product from ethylene glycol during the polymerization reaction, the content of the DEG component can be controlled not only when a predetermined amount of DEG is used as a polymerization raw material, but also by appropriately selecting reaction conditions and additives. However, the amount of DEG contained in ordinary PET is 1.0 mol% or more, and it is difficult to reduce it to less than 1.0 mol%. When it is more than 4.0 mol%, the effect of improving the crystallization rate of the polyester copolymer is small even when an antimony catalyst is used, and no superiority is recognized.

The content of antimony atom contained in the polyester copolymer of the present invention is 150 to 350 ppm, preferably 250 to 350 ppm. When it is less than 150 ppm, the polymerization reaction becomes slow and a polyester copolymer having a desired intrinsic viscosity cannot be obtained. When it is more than 350 ppm, the amount of catalyst residue is large, and the transparency of the obtained bottle is significantly lowered. Also, from the food hygiene regulations, 35
It is preferable to suppress it to 0 ppm or less.

The intrinsic viscosity of the polyester copolymer of the present invention is 0.70 to 1.50 dl / g, preferably 0.8.
It is 5 to 1.20 dl / g. If it is less than 0.70 dl / g, the moldability in blow molding will decrease, and if it exceeds 1.50 dl / g, the melt fluidity will decrease and the parison (preform)
Molding becomes difficult.

The polyester copolymer and the polyester heat-resistant bottle of the present invention can be manufactured as follows.

First, a polyester precursor is prepared by directly esterifying the above-mentioned dicarboxylic acid component and diol component according to a conventional method or transesterifying in the presence of an organic acid calcium salt. For example, a method of performing an esterification reaction under pressure using terephthalic acid, 2,6-naphthalenedicarboxylic acid and ethylene glycol, or using dimethyl terephthalate, dimethyl 2,6-naphthalenedicarboxylic acid and ethylene glycol in the presence of a catalyst. A method of carrying out a transesterification reaction can be mentioned.

Next, using an antimony compound as a polycondensation catalyst, a polycondensation reaction is carried out at 250 to 300 ° C. under reduced pressure to produce a polyester copolymer prepolymer having a desired viscosity. Antimony compounds include antimony oxides,
Examples thereof include inorganic acid salts, organic acid salts, and halides.
The catalyst amount is such that the content of antimony atom in the prepolymer to be produced or the copolyester after solid state polymerization is 1
50 to 350 ppm, preferably 250 to 350 ppm
It is desirable to use an appropriate amount so as to be in the range.

Further, in order to obtain the polyester copolymer of the present invention, it is necessary to solid-phase polymerize the above-mentioned prepolymer.

The prepolymer used for the solid phase polymerization is preliminarily crystallized by heating it to a temperature lower than the temperature at which the solid phase polymerization is carried out in advance. Such a pre-crystallization step is performed at a temperature of 120 to 200 ° C. in an inert gas stream such as nitrogen at a temperature of 0.5 to 0.5.
It can be carried out by heating for ~ 5 hours, preferably 0.5-2 hours. Alternatively, it can be performed by heating to a temperature of 120 to 200 ° C. for 0.5 to 5 hours, preferably 0.5 to 2 hours in an atmosphere of steam or a steam-containing inert gas.

The crystallized prepolymer is subjected to solid phase polymerization at a temperature of 190 to 230 ° C., preferably 200 to 220 ° C. under a vacuum or an inert gas flow to give a polyester copolymer having a desired degree of polymerization. Is obtained. The solid phase polymerization time is shorter as the polymerization temperature is higher, but it is usually 1
It is 0 to 50 hours, preferably 10 to 30 hours.

The above polyester copolymer is used in a water content of 100 p.
After drying to pm or less, preferably 50 ppm or less, a parison (preform) can be injection-molded, and the parison can be blow molded into a desired shape to mold a heat-resistant bottle. Alternatively, the hollow pipe may be formed by extrusion molding, one end is melted and closed, and the mouth part capable of attaching the cap is formed on the other end, and then blow molding may be performed.

The obtained bottle may be used as it is, but in the case of contents requiring heat filling, such as fruit juice and oolong tea, heat-set in a blow mold to impart heat resistance. To use. Heat setting is usually 100-2
It is carried out at 00 ° C. for several seconds to several minutes.

[0022]

By using the polyester copolymer having a high degree of polymerization of the present invention, a bottle excellent in moldability, mechanical strength, heat resistance and the like can be provided.

[0023]

The present invention will be described in more detail with reference to the following examples. The intrinsic viscosity, glass transition temperature, amount of naphthalene dicarboxylic acid component, amount of diethylene glycol component, and content of antimony atom of the polyester copolymers in Examples were measured by the following methods.

(1) Intrinsic viscosity (hereinafter referred to as IV) A solution prepared by dissolving 0.5 g of a polyester sample in 100 ml of a mixed solution of 60% by weight of phenol and 40% by weight of 1,1,2,2-tetrachloroethane was prepared. It was measured at 25 ° C.

(2) Glass transition temperature (hereinafter referred to as Tg) Approximately 10 mg of a polyester sample was measured with a scanning scanning calorimeter (DSC-8230 manufactured by Rigaku Corporation) at a temperature rising rate of 10 ° C./min. did. Glass transition temperature is JIS-K712
It was calculated as defined in 1.

(3) Amount of naphthalenedicarboxylic acid component (hereinafter referred to as 2,6-NDCA amount) A mixed solution of trifluoroacetic acid and chloroform (1: 1)
After the polyester sample was dissolved in, tetramethylsilane was mixed as a standard, and FT-NMR (3 manufactured by Varian)
(00MG type) was used for quantification by proton NMR spectrum. Ratio to all dicarboxylic acid components (mol%)
Indicated by.

(4) Amount of diethylene glycol component (hereinafter, referred to as DEG amount) A polyester sample was hydrolyzed by a conventional method, and the produced diol component was quantified by gas chromatography to obtain a ratio (mol%) to the total diol component. Indicated.

(5) Antimony atom content (hereinafter Sb
A polyester sample is dissolved in a hydrochloric acid solution by a conventional method,
It was quantified by inductively coupled plasma (ICP) emission spectrometry.

Example 1 117 mol of dimethyl terephthalate, 10 mol of dimethyl 2,6-naphthalenedicarboxylate, and ethylene glycol 2
79 mol and 22.64 g of calcium acetate as a transesterification reaction catalyst were charged into a polymerization vessel having a rectification column, and then heated and stirred at 250 ° C. while flowing a slight amount of nitrogen. During this period, the temperature of the rectification column was maintained at 60 to 70 ° C. to reflux ethylene glycol and distill only methanol out of the system.

As calculated from the amount of methanol collected, when the transesterification rate reached about 90%, 7.50 g of antimony trioxide (as compared to polymer 300) was used as a polymerization catalyst.
ppm), trimethyl phosphate 2.38 g as a heat stabilizer
(95 ppm of polymer) was added, the pressure was gradually reduced while continuing heating and stirring, and the inside of the can was adjusted to 1 torr over about 1 hour.
The following high vacuum was used. During this time, the temperature was raised to 280 ° C. After continuing the polymerization for about 3 hours in this state, the pressure was returned to normal pressure, extruded in a gut shape, cooled with water, and then cut into chips. Table 1 shows the analysis results of the obtained prepolymer.

Example 2 In Example 1, 114 mol of dimethyl terephthalate,
An experiment was conducted under the same conditions as in Example 1 except that the amount of dimethyl 2,6-naphthalenedicarboxylate was 13 mol. Table 1 shows the analysis results of the obtained prepolymer.

Example 3 In Example 1, 114 mol of dimethyl terephthalate,
An experiment was conducted under the same conditions as in Example 1 except that the amount of dimethyl 2,6-naphthalenedicarboxylate was 13 mol. Table 1 shows the analysis results of the obtained prepolymer.

Example 4 Under the same conditions as in Example 3, except that 10.00 g of antimony trioxide (400 ppm of polymer) and 3.18 g of trimethyl phosphate as a heat stabilizer (127 ppm of polymer) were used. An experiment was conducted. Table 1 shows the analysis results of the obtained prepolymer.

Comparative Example 1 In Example 1, 123 mol of dimethyl terephthalate,
The experiment was conducted under the same conditions as in Example 1 except that the amount of dimethyl 2,6-naphthalenedicarboxylate was 4 mol. Table 1 shows the analysis results of the obtained prepolymer.

Comparative Example 2 In Example 1, 102 mol of dimethyl terephthalate,
An experiment was conducted under the same conditions as in Example 1 except that 25 mol of dimethyl 2,6-naphthalenedicarboxylate was used. Table 1 shows the analysis results of the obtained prepolymer.

Comparative Example 3 In Example 1, 114 mol of dimethyl terephthalate,
Dimethyl 2,6-naphthalenedicarboxylate 13 mol, ethylene glycol 269 mol, diethylene glycol 1
An experiment was conducted under the same conditions as in Example 1 except that the amount was 0 mol. Table 1 shows the analysis results of the obtained prepolymer.

Comparative Example 4 An experiment was performed under the same conditions as in Example 1 except that 3.75 g of germanium dioxide (150 ppm of polymer) was used in place of antimony trioxide. Table 1 shows the analysis results of the obtained prepolymer.

Comparative Example 5 An experiment was conducted under the same conditions as in Example 2 except that 3.75 g of germanium dioxide (150 ppm of polymer) was used instead of antimony trioxide. Table 1 shows the analysis results of the obtained prepolymer.

Comparative Example 6 An experiment was carried out under the same conditions as in Example 3 except that 3.75 g of germanium dioxide (150 ppm of polymer) was used in place of antimony trioxide. Table 1 shows the analysis results of the obtained prepolymer.

[0040]

[Table 1]

Example 5 The prepolymer obtained in Example 1 was treated under vacuum at 130 ° C.
After crystallization for 2 hours at the temperature of
Solid phase polymerization was performed in a nitrogen stream for a period of time. Table 2 shows the analysis results of the obtained polyester copolymer.

Examples 6 to 8 The prepolymers obtained in Examples 2 to 4 were solid-phase polymerized in the same manner as in Example 5. Table 2 shows the analysis results of the obtained polyester copolymer.

Comparative Example 7 The prepolymer obtained in Comparative Example 1 was subjected to solid phase polymerization in the same manner as in Example 5. Table 2 shows the analysis results of the obtained polyester copolymer.

[0044]

[Table 2]

Comparative Examples 8 to 12 The prepolymers obtained in Comparative Examples 2 to 6 were solid-phase polymerized in the same manner as in Example 5. Fusion of polymer particles occurs,
The solid phase polymerization reaction was difficult. Moreover, the intrinsic viscosity of the obtained polyester copolymer was not uniform.

Example 9 The polyester copolymer obtained in Example 5 was treated under reduced pressure 1
Nissei AS is dried at 30 ℃ to a moisture content of 100ppm or less.
Polymer temperature 2 using B-50 type injection blow molding machine
Contents of 1 l at 85 ℃, 40 g of basis weight, cap diameter of 30 mm
10 bottles were molded. Each container was filled with 1 liter of 2 vol% carbonated water and capped, and after visually injecting hot water of 65 ° C. for 30 minutes, the appearance deformation of the containers was inspected. Table 3 shows the analysis results of the heat-resistant bottle.

Examples 10 to 12 The polyester copolymers obtained in Examples 6 to 8 were molded into bottles in the same manner as in Example 9, and their heat resistance was evaluated.
Table 3 shows the analysis results of the heat-resistant bottle.

Comparative Example 13 The polyester copolymer obtained in Comparative Example 7 was used in Example 9
It was molded into a bottle in the same manner as above, and its heat resistance was evaluated. Table 3 shows the analysis results of the heat-resistant bottle.

[0049]

[Table 3]

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[Procedure amendment]

[Submission date] June 23, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction content]

(1) Intrinsic viscosity (hereinafter referred to as IV) A solution prepared by dissolving 0.5 g of a polyester sample in 100 ml of a mixed solution of 60% by weight of phenol and 40% by weight of 1,1,2,2-tetrachloroethane was prepared. used, it was measured at 2 0 ℃.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

[0032] In Example 3 Example 1, dimethyl terephthalate 11 2 mol,
An experiment was conducted under the same conditions as in Example 1 except that the amount of dimethyl 2,6-naphthalenedicarboxylate was 15 mol. Table 1 shows the analysis results of the obtained prepolymer.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

Example 5 The prepolymer obtained in Example 1 was treated under vacuum at 130 ° C.
After over at the temperature for 2 hours to crystallize, 3 at 215 ° C. 0
Solid phase polymerization was performed in a nitrogen stream for a period of time. Table 2 shows the analysis results of the obtained polyester copolymer.

Claims (4)

[Claims] 1. A terephthalic acid as a dicarboxylic acid component,
A polyester copolymer containing ethylene glycol as a main component as a diol component, wherein (1) dicarboxylic acid component is 2,6-naphthalenedicarboxylic acid of 8.0 to 1
5.0 mol%, (2) Diethylene glycol as a diol component is 1.0 to 4.0 mol%, (3) Antimony atom content is 150 to 350 ppm, (4) Intrinsic viscosity is 0.70 to 1.50 dl / G, a polyester copolymer. 2. A bottle comprising the polyester copolymer according to claim 1. 3. A terephthalic acid as a dicarboxylic acid component,
A polyester copolymer containing ethylene glycol as a main component as a diol component, wherein (1) dicarboxylic acid component is 2,6-naphthalenedicarboxylic acid of 8.0 to 1
5.0 mol%, (2) Diethylene glycol as a diol component is 1.0 to 4.0 mol%, (3) Antimony atom content is 150 to 350 ppm, (4) Intrinsic viscosity is 0.50 to 0.70 dl The polyester copolymer according to claim 1, wherein the polyester copolymer is produced by solid-state polymerization of a prepolymer having a concentration of 1 / g. 4. A bottle comprising the polyester copolymer according to claim 3.