JP2605767B2 - Copolyester - Google Patents

Description

The present invention relates to a copolymerized polyester, which is excellent in transparency and gas permeation resistance and is useful as a packaging material for containers, films and the like.

[Conventional technology]

Polyester represented by polyethylene terephthalate has been widely used for fibers, films, etc. due to its excellent mechanical properties and chemical properties, but in recent years its excellent transparency, gas barrier properties, safety and health, etc. soda drink,
It has been used as a container for fruit juice drinks, liquid seasonings, edible oils, sake and wine, and recently as cups and trays.

In particular, in the use of carbonated drinks, fruit juice drinks, alcohol, wine, etc., gas permeation resistance is required in terms of content preservation,
Polyethylene terephthalate exhibits better gas permeability resistance than other resins such as polyolefins, but does not necessarily have sufficient gas permeability resistance.

Various methods have been proposed for further improving the gas permeability resistance of polyethylene terephthalate. For example, a method of coating or laminating a gas-permeable material such as polyvinylidene chloride, saponified ethylene-vinyl acetate copolymer, polyethylene isophthalate (Japanese Patent Application Laid-Open Nos. 54-117565 and 56-56).
64839, etc.), a method of blending a gas-permeable material (JP-A-57-10640), and a method of improving the gas-permeability by increasing the degree of orientation of polyester (JP-A-56-151648). I have.

However, in the method of coating or laminating polyvinylidene chloride or saponified ethylene-vinyl acetate copolymer, since a resin different from polyester is used together,
Poor adhesion to polyester causes delamination, resulting in not only loss of transparency of the container, but also disadvantage in terms of recovery.

Further, a method of coating or laminating polyethylene isophthalate has also been proposed, and since both layers are the same polyester, there is no such a defect.However, in order to impart strength as a container, it is brittle even when laminated. It is necessary to make polyethylene terephthalate as thick as that alone, and the container becomes heavier as a whole, losing the advantages of a synthetic resin container, and the effect of improving gas permeation resistance cannot be said to be sufficient. Further, in the method of increasing the degree of orientation of the polyester molded article, there is a limit in improving the gas permeation resistance.

Furthermore, polyalkylene isophthalate obtained by copolymerizing an aliphatic dicarboxylic acid having 4 to 12 carbon atoms has been proposed as a polyester for packaging materials instead of polyethylene terephthalate (US Pat. No. 4,403,090).
However, this polyester is not satisfactory for improving the gas permeation resistance of polyethylene terephthalate packaging materials.

Also known are copolyesters composed of a dicarboxylic acid mainly containing terephthalic acid and combined with 2,2'-oxydiacetic acid, 2,2'-iminodiacetic acid and the like, and a diol having about 8 or less carbon atoms, and a container made of the same. However, even in this case, the improvement in gas permeation resistance is not sufficient (US Pat. Nos. 4,436,895 and 4,546,170).

[Object of the invention]

An object of the present invention is to provide a copolymerized polyester which is excellent in physical properties such as mechanical strength and transparency and has excellent gas permeability resistance.

[Configuration of the invention]

The present invention relates to a copolymerized polyester obtained by polycondensing a dicarboxylic acid component and a diol component, wherein the ratio of dicarboxylic acid units derived from isophthalic acid or an ester-forming derivative thereof to all dicarboxylic acid units is 50 to 50.
It is 99 mol%, preferably 60 to 90 mol%, and has the general formula (1) HOOC-R ¹ -X-R ² -COOH (1) (wherein R ¹ and R ² are the same or different. Represents a divalent aliphatic group, and X represents O or NH.) The ratio of the dicarboxylic acid units derived from the dicarboxylic acid or the ester-forming derivative thereof to the total dicarboxylic acid units is 1 to 50. Mol%, preferably 10 to 40 mol%, of the general formula (2) (Wherein R ³ and R ⁴ may be the same or different and each represents a divalent aliphatic group or an aromatic group.) The ratio of the diol unit derived from the diol represented by 100 mol%, the intrinsic viscosity [phenol /
Using a mixed solvent of tetrachloroethane (weight ratio 1/1)
[Measured at 0 ° C.] of 0.4 to 2 dl / g.

In the general formula (1), R ¹ and R ^{2 each} have 1 carbon atom in the main chain.
To 4 aliphatic hydrocarbon divalent residues. Hydrogen, an alkyl group having 1 to 4 carbon atoms and the like are bonded to the main chain, and the position of the bond is not particularly limited.

Specific examples of the dicarboxylic acid represented by the general formula (1) include 2,2'-oxydiacetic acid (diglycolic acid) and 3,3'-
Oxydipropionic acid (diethyl ether-β, β'-
Dicarboxylic acid), 2,2'-oxydipropionic acid, 4,4 '
-Oxydibutyric acid, 2,2'-iminodiacetic acid, 3,3'-iminodipropionic acid, 2,2'-iminodipropionic acid, 4,4 '
-Iminodibutyric acid, 3,3'-iminodibutyric acid and the like,
In particular, 2,2'-oxydiacetic acid and 2,2'-iminodiacetic acid are preferably used.

In the general formula (2), R ³ and R ⁴ are a divalent aliphatic group or an aromatic group, and include the following.

(A) The main chain is a divalent residue of an aliphatic hydrocarbon having 1 to 4 aliphatic hydrocarbons, and the main chain has hydrogen, halogen, and 1 to 4 carbon atoms.
4, an alkyl group, a phenyl group, a benzyl group, and the like. The position of the bond and the like are not particularly limited. Specific examples of such a diol represented by the general formula (2) containing R ³ and R ⁴ include 1,3-bis (2-hydroxyethoxy) benzene, 1,3-bis (2-hydroxy-1- Chloroethoxy) benzene, 1,3-bis (2-hydroxy-1,1-dichloroethoxy) benzene, 1,3-bis (2-hydroxy-1-methylethoxy) benzene, 1,3-bis (2-
(Hydroxy-2-methylethoxy) benzene, 1,3-bis (2-hydroxy-1-ethylethoxy) benzene,
1,3-bis (2-hydroxy-1-ethylethoxy) benzene, 1,3-bis (2-hydroxy-1,2-dimethylethoxy) benzene, 1,3-bis (2-hydroxy-1,1,1
-Dimethylethoxy) benzene, 1,3-bis (2-hydroxy-1,2,2-trimethylethoxy) benzene, 1,3-
Bis (2-hydroxy-1,1,2,2-tetramethylethoxy) benzene, 1,3-bis (2-hydroxy-1,1-diethylethoxy) benzene, 1,3-bis (2-hydroxy-2 , 2-Diethylethoxy) benzene, 1,3-bis (2-
(Hydroxy-1-methyl-2-ethylethoxy) benzene, 1,3-bis (2-hydroxy-1-propylethoxy) benzene, 1,3-bis (2-hydroxy-2-propylethoxy) benzene, 1,3 -Bis (2-hydroxy-2-benzylethoxy) benzene, 1,3-bis (3-
(Hydroxypropoxy) benzene, 1,3-bis (3-hydroxy-3-phenylpropoxy) benzene, and the like.

(B) A phenylene group which is an aromatic group, wherein the hydrogen atom may be substituted with an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a halogen, or the like. Specific examples of the general formula (2) containing R ³ and R ⁴ include 1,3-bis (o-hydroxymethylphenoxy) benzene and 1,3-bis (p-
(Hydroxymethylphenoxy) benzene, 1,3-bis (m-hydroxymethylphenoxy) benzene, and the like.

(C) Furthermore, the above (a) and (b) are simultaneously satisfied
R ³ and R ⁴ can also be used. Specific examples of the general formula (2) containing such R ³ and R ⁴ include 1,3-bis (p-oxybenzyloxy) benzene and 1,3-bis (o-oxybenzyloxy) benzene. Can be

The compounds exemplified in (a), (b) and (c) are 1,3
Although it is a isomer, a 1,2- or 1,4-phenyl nucleus-substituted isomer can be used in the same manner. Further, in the general formula (2), the central phenyl nucleus may be substituted with an alkyl group. For example, 1,3-bis (2-hydroxyethoxy) -4-methylbenzene 1,4-bis (o-hydroxymethylphenoxy) -3-ethylbenzene can be used in the same manner.

Isophthalic acid and the dicarboxylic acid represented by the general formula (1) can be used as they are in the form of a free acid, but are ester-forming derivatives which form an ester by reacting with a hydroxyl group, for example, esterified products such as monoester and diester. And acid halides such as acid chloride.

The diol component represented by the general formula (2) is used in an amount of at least 3 mol%, preferably 3 to 80 mol%, more preferably 8 to 60 mol%, based on all diol components.

Examples of the diol component other than the general formula (2) include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexane dimethanol, diethylene glycol, and bisphenol A and bisphenol S. And the like. Of these, ethylene glycol is most preferred. Of these, several diol components can be used in combination as long as the above-mentioned conditions are satisfied.

Further, as long as the copolymerized polyester of the present invention substantially maintains linearity, polyfunctional compounds such as trimethylolpropane, pentaerythritol, glycerin, trimellitic acid, trimesic acid, and pyromellitic acid, and o-benzoylbenzoic acid May be copolymerized.
Such a polyfunctional compound or monofunctional compound is a diol component of 20%.
It is used in the range of mol% or less.

After completion of the polymerization reaction, the copolymerized polyester of the present invention is withdrawn from the reaction vessel and cut into chips, or after injection, extrusion, from the viewpoint of moldability at the time of blow molding, the viscosity of the melt is a certain level. Need to hold more
Furthermore, when formed into containers such as bottles, barrels, cans and the like, films, sheets and the like, it is necessary to have physical properties that can withstand practical use. Therefore, the intrinsic viscosity [phenol / tetrachloroethane (weight ratio 1/1/1) ) Using a mixed solvent at 30 ° C.] is 0.4 or more, 2 or less, preferably 0.55 or more,
The following are used:

Such a copolymerized polyester can be produced by a conventionally known method for polyethylene terephthalate. For example, isophthalic acid and a dicarboxylic acid of the general formula (1), specifically 2,2'-dioxyacetic acid, a diol of the general formula (2), specifically 1,3-bis (2-hydroxyethoxy) ) A transesterification reaction using benzene and ethylene glycol, followed by polycondensation of the resulting reaction product.

The dicarboxylic acid of the general formula (1) and its ester-forming derivative, and the diol of the general formula (2) may be added from the beginning of the esterification or transesterification reaction,
After completion of esterification or transesterification, or
Further, it can be added at any stage during the polycondensation. In these esterification, transesterification and polycondensation reactions, it is preferable to use an esterification catalyst, a transesterification catalyst, a polycondensation catalyst and a stabilizer.

As the transesterification catalyst, known compounds, for example,
One or more of calcium, manganese, zinc, sodium, and a lithium compound can be used, but a manganese compound is particularly preferable in terms of transparency.

As the polymerization catalyst, one or more known antimony, germanium, titanium, and cobalt compounds can be used, but antimony, germanium, and a titanium compound are preferably used.

In the present invention, if necessary, conventionally known additives, for example, antioxidants, ultraviolet absorbers, optical brighteners,
A release agent, an antistatic agent, a coloring agent such as a dispersant and a dye or pigment may be added at any stage during polyester production,
Before the forming process, it may be added by a so-called master batch processing method.

The copolymerized polyester of the present invention further comprises, if necessary,
The solid phase polymerization treatment may be performed to increase the degree of polymerization, lower the acetaldehyde, or lower the oligomer before use. It is preferable that the solid-phase polymerization treatment is usually carried out at a temperature of from 190 ° C. to a temperature just below the melting point for several tens of hours or less after crystallization of the chip surface at a temperature of 80 to 180 ° C.

The copolyester of the present invention thus obtained is melt-molded to obtain a molded article.

Specifically, polyethylene terephthalate (PET),
Polybutylene terephthalate, polyethylene naphthalate, polyester elastomer, polycarbonate and other thermoplastic resin components such as polyamide such as nylon 6, nylon 66, meta-xylylenediamine adipamide,
It is possible to blend the copolymerized polyester of the present invention to form an integral structure, and further, a multilayer of the polyethylene terephthalate component or the thermoplastic resin component as described above and the copolymerized polyester component of the present invention. It can also be formed into a structure.

At this time, all the melt molding methods generally used in molding of polyethylene terephthalate and the like can be applied.

Specifically, for example, in order to obtain a hollow molded body, a preform is once formed by a usual extrusion blowing method, an injection blowing method, injection molding or extrusion molding, and then, as it is, or a plug. A blow molding method such as a hot parison method or a cold parison method in which the part and the bottom are processed and then reheated and then biaxially stretched is applied.

Also, in the case of a multilayer container, it can be manufactured according to a conventional molding method such as polyethylene terephthalate. That is, a normal injection molding machine or a multilayer parison molded by an injection molding machine having a plurality of injection devices, or
A multilayer parison obtained by bottoming one end of a multilayer parison formed by a multilayer extrusion molding machine, for example, 85 to 130
It can be manufactured by a method of stretching at a PET stretching temperature of ° C.

When the copolyester of the present invention is formed in a multilayer container, the formation of the layers is not particularly limited, and the number of layers is not particularly limited, but a configuration of about 3 to 5 layers is preferable.

In addition, after being formed into a sheet by injection molding, it can be formed into a uniaxial or biaxially stretched film, or can be formed into a can-shaped container or tray by vacuum forming or pressure forming,
For example, a multilayer extruder can be used to form a multilayer sheet with polyethylene terephthalate and similarly form a uniaxially or biaxially stretched film, a can-shaped container, or a tray.

When the copolyester of the present invention and the various polymers described above are blended to form a packaging material, both components are melt-kneaded with an extruder to obtain a mixed chip, which can then be subjected to molding. Alternatively, each component can be dry blended and directly provided for molding.

As such molded articles to be subjected to the present invention, specifically, containers such as bottles, barrels, cans and the like, and containers obtained by deep drawing an unstretched sheet, and further obtained by vacuum or pressure forming the sheet are obtained. Containers such as trays.

〔The invention's effect〕

The copolyester of the present invention exhibits high transparency per se and has excellent gas permeation resistance. The copolymerized polyester of the present invention is useful as a packaging material, as a blend or a laminate with another thermoplastic resin, a container, a sheet,
It can be widely used for films and the like. In particular, a blend or laminate with a polyethylene terephthalate component can be used very advantageously because it has low gas permeability and maintains high transparency.

Further, it can be used in combination with a gas-permeable material such as vinylidene chloride or saponified ethylene-vinyl acetate copolymer.

〔Example〕

Hereinafter, the present invention will be described in more detail by examples,
The present invention is not limited to the following examples unless it exceeds the gist.

In the examples, "parts" means "parts by weight", and various measuring methods used in the examples are shown below.

Intrinsic viscosity phenol-tetrachloroethane (50/50 weight ratio)
It was measured at 30 ° C in the middle.

Prepare an extruded sheet sample with an oxygen permeability of about 200μ
Measured with an “OX-TRAN 10 / 50A” oxygen permeability measuring device (manufactured by Modern Controls, USA) under the condition of 00% RH, and cc · mm / m ²
-Day / atm.

Composition of Copolyester Determined from nuclear magnetic resonance spectrum using trifluoroacetic acid solvent.

Example 1 16,000 parts of isophthalic acid, 6,000 ethylene glycol
Parts, 2,280 parts of 2,2'-oxydiacetic acid and 3,200 parts of 1,3-bis (2-hydroxyethoxy) benzene were charged into a reaction vessel, and stirred under a nitrogen atmosphere under pressure (2.5 kg / cm ² ) while stirring.
The esterification reaction was carried out at 245245 ° C. for 3 hours, and water generated during this time was distilled out of the system.

To this esterified product, 16 parts of titanium tetrabutoxide were added, and the inside of the polymerization tank was gradually reduced in pressure from normal pressure.
The temperature was gradually raised, and a transparent polyester having an intrinsic viscosity of 0.68 was obtained at 260 ° C. under a vacuum of 1 torr for a total polymerization time of 5 hours.

Table 1 shows the oxygen gas permeability measured for a 208 μm extruded sheet of this polyester.

Example 2 15,000 parts of dimethyl isophthalate, 11,000 parts of ethylene glycol and 4 parts of manganese acetate tetrahydrate were added to a reaction vessel, and the temperature was gradually raised from 160 ° C to 230 ° C, and transesterification was performed until no distillate was produced. Was done.

To this system, 2,600 parts of 2,2'-iminodiacetic acid, 3,900 parts of 1,3-bis (2-hydroxyethoxy) benzene, 2.7 parts of orthophosphoric acid and 2.0 parts of germanium dioxide were added.
In the same manner as in the above, a transparent polyester having an intrinsic viscosity of 0.70 was obtained over a total polymerization time of 4 hours.

Table 1 shows the oxygen gas permeability measured with a 205 µ extruded sheet of this polyester.

Example 3 3,000 parts of the copolyester obtained in Example 1 and 7,000 parts of a commercially available polyethylene terephthalate resin for a carbonated beverage were dry-blended and operated in the same manner as in Example 1 to obtain a 220 μ sheet.

This sheet is placed in a long stretching machine, and the temperature of
Simultaneous biaxial stretching was performed three times.

Oxygen permeability of this stretched ^{film, 1.0cc · mm / m 2 ·} da
At y · atm, the value was 1/2 of that of a PET single stretched film stretched and produced under the same conditions.

Example 4 Instead of 1,280 parts of 2,2'-oxydiacetic acid and 3,200 parts of 1,3-bis (2-hydroxyethoxy) benzene, 2,2'-
A transparent polyester having an intrinsic viscosity of 0.68 was obtained in the same manner as in Example 1, except that 3,120 parts of oxydiacetic acid and 3,200 parts of 1,4-bis (2, hydroxyethoxy) benzene were used. Table 1 shows the oxygen gas permeability measured for a 208 μm extruded sheet of this polyester.

Example 5 A transparent polyester having an intrinsic viscosity of 0.69 was obtained in the same manner as in Example 1 except that 4,250 parts of 3,3'-oxydipropionic acid was used instead of 1,280 parts of 2,2'-oxydiacetic acid. Table 1 shows the oxygen gas permeability measured for a 208 μm extruded sheet of this polyester.

Comparative Example 1 1,280 parts of 2,2'-oxydiacetic acid was used as 1,440 parts to give 1,3-
The procedure was performed in the same manner as in Example 1 except that bis (2-hydroxyethoxy) benzene was not used. Table 1 shows the oxygen gas permeability of the obtained polyester obtained by extruding a 208 μ sheet.

Comparative Example 2 16,000 parts of isophthalic acid and 7,200 parts of ethylene glycol were charged into a reaction vessel, and the mixture was placed under a nitrogen atmosphere under pressure (2.5 kg / cm ² ).
While stirring, the esterification reaction was carried out at 230 to 245 ° C. for 3 hours, and water generated during the reaction was distilled out of the system.

To this esterified product, 16 parts of titanium tetrabutoxide were added, and the inside of the polymerization tank was gradually reduced in pressure from normal pressure.
The temperature was gradually raised, and a transparent polyester having an intrinsic viscosity of 0.70 was obtained at 260 ° C. under a vacuum of 1 torr for a total polymerization time of 5 hours.

Table 1 shows the oxygen gas permeability measured for a 208 μm extruded sheet of this polyester.

Claims (5)

(57) [Claims] In a copolymerized polyester obtained by polycondensation of a dicarboxylic acid component and a diol component, the ratio of dicarboxylic acid units derived from isophthalic acid or an ester-forming derivative thereof to all dicarboxylic acid units is 50 to 99.
%, And the general formula (1) HOOC-R ¹ -X-R ² -COOH (1) (wherein R ¹ and R ² may be the same or different, and may be a divalent aliphatic group. X represents O or NH.) The ratio of the dicarboxylic acid unit derived from the dicarboxylic acid or the ester-forming derivative thereof represented by the formula to the total dicarboxylic acid units is 1 to 50 mol%, and the compound represented by the general formula (2) ) (Wherein R ³ and R ⁴ may be the same or different and each represent a divalent aliphatic group or an aromatic group.) The ratio of the diol unit derived from the diol represented by And a limiting viscosity [value measured at 30 ° C. using a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1)] of 0.4 to 2 dl / g. . 2. A dicarboxylic acid represented by the general formula (1):
2. The copolymerized polyester according to claim 1, which is 2,2'-oxydiacetic acid or 2,2'-iminodiacetic acid. 3. The diol represented by the general formula (2) is 1,3
The copolymerized polyester according to claim 1, wherein the copolymerized polyester is -bis (2-hydroxyethoxy) benzene. 4. A ratio of 0 to 97 based on the total diol unit.
2. The copolyester according to claim 1, which contains mol% of ethylene glycol units. (5) a ratio of 3 to 80 relative to the total diol unit;
4. The method according to claim 3, wherein said composition contains mol% of 1,3-bis (2-hydroxyethoxy) benzene unit.
Item 10. The copolymerized polyester according to item 8.