JP3099473B2 - Copolyester and molded article composed thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolymerized polyester useful for bottles, films, sheets and the like. More specifically, the present invention relates to a copolyester excellent in heat resistance and having a low oligomer content that does not easily cause contamination of a mold or the like during molding, and a molded article thereof.

[0002]

2. Description of the Related Art Polyethylene terephthalate (hereinafter, referred to as "polyethylene terephthalate")
"PET") is excellent in mechanical strength, chemical stability, transparency, hygiene, etc., and is lightweight and inexpensive, so it is widely used as a variety of sheets and containers for packaging materials, , Carbonated drinks, fruit juice drinks, liquid seasonings, edible oils, liquor, wine, containers for wine are growing remarkably.

[0003] In the case of such a PET, for example, in the case of a bottle, a preform for a hollow molded body is molded by an injection molding machine, and this preform is stretch-blown in a mold having a predetermined shape. In addition, in the case of a content liquid that requires heat filling such as a fruit juice beverage, it is general that the liquid is generally heat-fixed and molded into a bottle in the blow mold or a separately provided mold. It is.

However, in conventional PET chips used for molding, the amount of the cyclic trimer containing oligomer as a main component is usually 1 to 2% by weight in a melt-polymerized chip, and usually 0.5% in an individual-phase polymerized chip. ~ 1.0% by weight, these oligomers adhere to equipment such as molds during molding,
To contaminate. The contamination of the mold and the like causes the surface roughness and whitening of the molded product. For this reason, it is necessary to clean the mold and the like as frequently as possible.

Therefore, attempts have been made to lower the oligomers by extending the solid-phase polymerization time or increasing the amount of the catalyst. However, the reduction of oligomers by such a method is limited and economical. Is not a good way. On the other hand, copolyesters having properties similar to PET, for example, copolyesters using terephthalic acid and isophthalic acid as dicarboxylic acid components, and copolyesters using ethylene glycol and diethylene glycol as glycol components, are well known. Have been. However,
The amount of oligomer is reduced to a certain degree or more, and PET
Copolyesters having properties equal to or better than those of the above have not been specifically known.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a copolymerized polyester which is less likely to cause contamination of a mold or the like during molding, has a low oligomer content, and has heat resistance equal to or higher than that of conventional PET. It is in.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the object, and as a result, have found that a conventional polyester containing a small amount of cyclohexane dimethanol and diethylene glycol in a specific range of physical properties has been produced. Found and arrived at the present invention. That is, the gist of the present invention is:
A copolymerized polyester containing terephthalic acid as a dicarboxylic acid component and ethylene glycol as a diol component, wherein (1) 0.1 to 5.0 mol% of cyclohexanedimethanol and 0.2 to 0.2% of diethylene glycol as diol components. (2) the content of the cyclic trimer is 0.35% by weight or less, (3) the intrinsic viscosity is 0.50 to 1.50 dl / g, and (4) the density is 1.37 g. / Cm ³ or more, (5) low-temperature crystallization peak temperature (Tc) obtained by a differential scanning calorimeter is 120 to 185
° C, and a molded article comprising the copolymerized polyester.

Hereinafter, the present invention will be described in detail. In the copolymerized polyester of the present invention, for terephthalic acid and ethylene glycol as main components, known raw materials used in PET may be used. The cyclohexanedimethanol raw materials of the present invention include 1,2-1,3- and 1,4
-Cyclohexane dimethanol, and its cis,
The trans isomer ratio may be a mixture of any ratio. Of these, usually 1,4-cyclohexane dimethanol,
Those having a cis / trans ratio of (20 to 80) / (80 to 20) are particularly preferably used.

Further, diethylene glycol (hereinafter referred to as "DE
G)), by-produced partly from ethylene glycol during the polymerization reaction. In addition to using a predetermined amount of diethylene glycol or its ester-forming derivative as a polymerization raw material, reaction conditions, additives, etc. The DEG content can be controlled only by making a selection. For example, tertiary amines such as triethylamine, tri-n-butylamine and benzyldimethylamine, quaternary ammonium hydroxides such as tetraethylammonium hydroxide, tetrabutylammonium hydroxide and trimethylbenzylammonium hydroxide and lithium carbonate and sodium carbonate By adding a small amount of a basic compound such as potassium carbonate and sodium acetate, the generation of DEG can be suppressed. On the other hand, if a small amount of an inorganic acid such as sulfuric acid or an organic acid such as benzoic acid is added to the polymerization raw material, the production of DEG can be promoted and the content can be increased.

These DEG control agents are used, if necessary, usually in an amount of 0.001 to 10% by weight, preferably 0.005 to 1% by weight, based on the total amount of the raw materials for polymerization. In the copolymerized polyester of the present invention, cyclohexanedimethanol is 0.1 to 5.0 mol%, preferably 0.2 to 3.5 mol%, and D is based on all diol components.
EG is 0.2 to 3.0 mol%, preferably 0.2 to 2.
It is contained in the range of 5 mol%. When it is less than the above range, the effect of reducing the oligomer is small, and superiority over conventional PET is not recognized. On the other hand, if it exceeds the above range, the amount of the oligomer tends to increase, and the crystallinity decreases, which is not preferable. In the above raw material composition, a copolymer polyester having a content of the cyclic trimer, which is the main component of the oligomer, of 0.35% by weight or less can be easily obtained.

Next, the intrinsic viscosity of the copolymerized polyester of the present invention is phenol / tetrachloroethane (weight ratio 1/1).
0.50-1.
50 dl / g, preferably 0.70 to 1.00 dl / g
It is. If it is less than 0.5 dl / g, the strength of the obtained copolymerized polyester is low, and after completion of the polymerization reaction, it is difficult to withdraw the copolyester from the reaction can to form chips, and it may have a sufficient strength and elongation as a molded product. Absent. On the other hand, if it exceeds 1.5 dl / g, the melt viscosity becomes too high, and the amount of shear heat generated in the valve during injection and extrusion becomes large. As a result, no improvement in contamination of a mold or the like is observed, which is not preferable.

The density of the copolymerized polyester of the present invention, when measured at 23 ° C. by a density gradient tube using a mixed solvent of carbon tetrachloride / n-heptane, is 1.37 g / cm ³ or more, preferably 1.37 g / cm ³ or more. It is at least 38 g / cm ^3, more preferably at least 1.39 g / cm ³ . If it is not more than 1.37 g / cm ³ , the amorphous fraction of the copolymerized polyester is still high, so that the oligomer cannot be reduced efficiently.

The crystallization characteristics of the copolymerized polyester of the present invention are as follows.
It is 0-185 degreeC, Preferably it is 130-180 degreeC, More preferably, it is 135-170 degreeC. Tc was measured by a differential scanning calorimeter using a differential scanning calorimeter. The copolymerized polyester sample was melted and held at 300 ° C. for 5 minutes. The sample was once taken out, immediately immersed in liquid nitrogen for several seconds, rapidly cooled, and left at room temperature. The heating curve obtained when the sample is returned to the apparatus and heated at a rate of 20 ° C./min from room temperature is obtained from an exothermic peak due to low-temperature crystallization.
When Tc is out of the above-mentioned range, it is difficult to obtain appropriate crystallinity as a usual molding material, and the heat resistance tends to decrease.

The above-mentioned copolymerized polyester of the present invention comprises P
The ET is produced by a conventionally known method by performing melt polymerization followed by solid phase polymerization. Hereinafter, the manufacturing method will be described in detail. As a melt polymerization method, for example, there is a method in which after a direct esterification reaction is performed under pressure using terephthalic acid, ethylene glycol and cyclohexane dimethanol, the temperature is further raised and the pressure is gradually reduced to carry out a polycondensation reaction. Alternatively, it can be produced by subjecting a transesterification reaction to an ester derivative of terephthalic acid, for example, dimethyl terephthalate, with ethylene glycol and cyclohexanedimethanol, and further polycondensing the obtained reaction product. In these polycondensation reactions, cyclohexanedimethanol may be added at any time during the esterification reaction, transesterification reaction, or polycondensation reaction at the initial stage. Preferably, it is added early.

Such a polycondensation reaction may be performed in one step or may be performed in a plurality of steps. When the polycondensation reaction is carried out in a plurality of stages, the reaction temperature of the first stage polycondensation is usually from 250 to 290 ° C, preferably from 260 to 2 ° C.
80 ° C., the pressure is usually 500 to 20 Torr, preferably 200 to 30 Torr, and the temperature of the final polycondensation reaction is usually 265 to 300 ° C., preferably 270.
To 295 ° C., and the pressure is usually 10 to 0.1 Torr, preferably 5 to 0.5 Torr.

When the polycondensation reaction is carried out in two stages,
The polycondensation reaction conditions of the first stage and the second stage are in the above ranges, respectively. When the polycondensation reaction is carried out in three or more stages, the polycondensation reaction from the second stage to the immediately preceding stage of the final stage is performed. Are the conditions between the above-mentioned first-stage reaction conditions and the last-stage reaction conditions. For example, when the polycondensation reaction is carried out in three stages, the reaction temperature of the second stage polycondensation reaction is usually 260 to 295 ° C, preferably 270 to 285 ° C, and the pressure is usually 50 to 2 Torr. , Preferably in the range of 40-5 torr. The intrinsic viscosity reached in each of these polycondensation reaction steps is not particularly limited, but it is preferable that the degree of increase in the intrinsic viscosity in each stage is smoothly distributed, and further from the final stage polycondensation reactor. The intrinsic viscosity of the obtained copolymerized polyester is usually 0.45 to
0.80 dl / g, preferably 0.50 to 0.75 dl
/ G, and the density is usually 1.33 to 1.35 g / cm
³ The copolyester thus obtained is usually formed into granular chips by a melt extrusion molding method.

Such a granular copolyester chip is usually 2.0 to 5.5 mm, preferably 2.2 to 5.5 mm.
It is desirable to have an average particle size of 4.0 mm. In these esterification, transesterification, and polycondensation reactions, it is preferable to use an esterification catalyst, a transesterification catalyst, a polycondensation catalyst, a stabilizer, and the like.

As the transesterification catalyst, known compounds, for example, one or more of calcium, manganese, zinc, titanium, sodium and lithium compounds can be used, but manganese or titanium compounds are particularly preferred from the viewpoint of transparency. . Examples of the polymerization catalyst include known antimony, germanium, titanium and cobalt compounds.
More than one species can be used, but preferably a compound of antimony, titanium or germanium is used.
The amount of the catalyst is usually 0.0005 to 0.2% by weight, preferably 0.001 to 0.05% by weight, based on the total amount of the raw materials for polymerization, for both the esterification catalyst and the polymerization catalyst.

Examples of the stabilizer include phosphoric esters such as trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate and tricresyl phosphate, triphenyl phosphite, trisdodecyl phosphate and the like. Phosphites such as phytate, trisnonylphenyl phosphite, acid phosphates such as methyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, dibutyl phosphate, monobutyl phosphate, dioctyl phosphate and phosphoric acid, phosphorous acid, A phosphorus compound such as polyphosphoric acid is used. The stabilizer is usually used in an amount of 0.001 to 0.1 as a weight of phosphorus atom in the stabilizer, in all the polymerization raw materials.
% By weight, preferably in the range of 0.002 to 0.02% by weight.

Further, as long as the constitutional requirements of the present invention are not deviated, a small amount of a dicarboxylic acid component other than terephthalic acid and naphthalenedicarboxylic acid and a diol component other than ethylene glycol, diethylene glycol and cyclohexanedimethanol may be contained. Good. These dicarboxylic acid components include phthalic acid, isophthalic acid, naphthalenedicarboxylic acid diphenyl sulfone dicarboxylic acid, 4,4′-biphenyl dicarboxylic acid and structural isomers thereof, and aliphatic dicarboxylic acids such as malonic acid, succinic acid and adipic acid. Examples of the acid, oxyacid or derivative thereof include p-hydroxybenzoic acid, p-hydroxybenzoic acid ester, and glycolic acid. As the diol component, 1,2-propanediol, 1,3
-Aliphatic glycols such as propanediol, 1,4-butanediol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, and diethylene glycol; and aromatic dihydroxy compound derivatives such as bisphenol A and bisphenol S. . All diol components and all dicarboxylic acid components are used in amounts that are substantially equivalent.

Next, in order to obtain the copolymerized polyester of the present invention, it is necessary to further subject the granular copolymerized polyester chips obtained by the melt polymerization as described above to a solid phase polymerization treatment. The copolyester chips supplied to the solid-phase polymerization may be preliminarily crystallized by heating to a temperature lower than the temperature at which the solid-phase polycondensation is performed, and then supplied to the solid-phase polycondensation step. In such a pre-crystallization step, the copolyester chips are dried in a dry state, usually 120 to 200.
C., preferably 130 to 180 ° C., for 1 minute to 4 hours. Alternatively, the chip is usually heated to 120 to 180 ° C. in an atmosphere of steam or an inert gas containing steam.
It can be carried out by heating at a temperature of 200 ° C. for 1 minute or more.

The solid-state polymerization step in which the above-mentioned granular copolyester chips are supplied comprises at least one stage, and the polymerization temperature is usually 190 to 230 ° C., preferably 19 to 230 ° C.
5 to 225 ° C. and the pressure is usually 1 kg / cm ² G to
It is carried out under an atmosphere of an inert gas such as nitrogen, argon or carbon dioxide under the conditions of 10 Torr, preferably normal pressure to 100 Torr. The polymerization time reaches desired physical properties in a shorter time as the temperature is higher, but is usually 1 to 50 hours, preferably 5 to 30 hours, more preferably 10 to 25 hours.

The copolymer polyester of the present invention can be obtained by appropriately selecting the conditions for the above solid phase polymerization treatment. The polyester of the present invention thus obtained can be used to form films, sheets, containers, and other packaging materials by using a melt molding method generally used for PET. Further, the mechanical strength can be improved by stretching the copolymerized polyester at least in a uniaxial direction.

In producing a stretched film, the stretching temperature may be set between the glass transition temperature of the copolymerized polyester of the present invention and a temperature 70 ° C. higher than that, usually 40 to 170 ° C., preferably 60 to 140 ° C. ° C. The stretching may be uniaxial or biaxial, but is preferably biaxial in view of practical physical properties of the film. The stretching ratio is usually 1.1 to 10 times, preferably 1.5 to 10 times in the case of uniaxial stretching.
In the case of biaxial stretching, the stretching may be performed in a range of usually 1.1 to 8 times, preferably 1.5 to 5 times in both the vertical and horizontal directions. Also, the vertical magnification /
The lateral magnification is usually 0.5-2, preferably 0.7-1.
3. The obtained stretched film is further heat-set,
Heat resistance and mechanical strength can also be improved. The heat setting is usually performed at a temperature of 120 ° C. to the melting point, preferably 150 to 230 ° C. under tension by compressed air or the like, usually for several seconds to several hours, preferably for several tens seconds to several minutes.

The container formed from the sheet can be extruded or formed into a well-known compressed air, vacuum formed or injection molded sheet.
It is manufactured by performing press molding and the like. At this time, the raw sheet may be lightly stretch-oriented, but non-oriented is preferably used. The molding temperature is
The raw sheet is heated at 50 to 200 ° C., preferably at 70 to 200 ° C.
After heating at 170 ° C. for several seconds to several minutes, preferably for several seconds to several tens of seconds, molding may be performed according to the above-described method. After molding, the glass may be rapidly cooled to a temperature below the glass transition temperature,
The temperature may be maintained at a temperature of not less than ° C. and heat set.

In producing the hollow molded article, a preform formed from the copolymerized polyester of the present invention is stretch blow-molded, and an apparatus conventionally used in PET blow molding can be used. . Specifically, for example, a preform may be molded once by injection molding or extrusion molding, and may be biaxially stretched and blown as it is or after processing the plug portion and the bottom portion and then reheating it. The biaxial stretch blow molding method such as the hot parison method or the cold parison method is applied to the copolymerized polyester of the present invention. The molding temperature in this case, specifically, the temperature of each part of the cylinder and the nozzle of the molding machine is usually in the range of 260 to 280 ° C.
The temperature can be set as low as -10 ° C, and it is easy to keep the oligomer amount low. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 1.5 to 3.5 times in the longitudinal direction and 2 to 5 times in the circumferential direction. .

The obtained hollow molded article can be used as it is. In particular, in the case of a content liquid which requires hot filling such as a fruit juice beverage, oolong tea, etc., it is generally heat-fixed in a blow mold. , And further used with heat resistance. The heat setting is usually performed under a tension of, for example, compressed air, 100 to 200.
C., preferably at 120 to 180.degree. C., for several seconds to several hours, preferably for several seconds to several minutes.

[0028]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist. In addition, various measurement methods used in this example are described below. The methods for measuring the intrinsic viscosity and the density are as described above. (1) Amount of diethylene glycol (DEG) and cyclohexane dimethanol The diol component produced by hydrolysis by a conventional method was quantified by gas chromatography. (2) Amount of cyclic trimer (hereinafter referred to as “CT amount”)
The mixture was melted in 2 ml of a mixed solution of hexafluoroisopropanol (volume ratio: 3/2), and further diluted with 20 ml of chloroform. To this, 10 ml of methanol was added to reprecipitate the sample, and a filtrate after filtration was obtained. After drying the filtrate,
A solution of the residue dissolved in 25 ml of dimethylformamide was analyzed and quantified by reverse phase chromatography. (3) Low temperature crystallization temperature (Tc) SEIKO I & E, SSC / 580 as a differential calorimeter
(DSC20) Measured using a thermal controller (manufactured by Seiko Instruments Inc.). (4) Acetaldehyde amount After water extraction at 160 ° C. for 2 hours, the amount was determined by gas chromatography. (5) Inert gas flow rate The inert gas flow rate is defined as the gas flow per unit time (hr) and per unit resin weight (kg) is 1 atm, 25 ° C.
It was shown by volume (L) converted to. (6) Strong elongation properties According to JIS K7113, at 23 ° C. and 50% RH, I
NTESCO Model 2001 (INTESCO
(Manufactured by the company).

Example 1 13.0 kg of terephthalic acid, 5.8 of ethylene glycol
A slurry of 2 kg and 0.27 kg of 1,4-cyclohexanedimethanol (cis / trans 3/7) was prepared, and 0.30 kg of bis-β-hydroxyethyl terephthalate was previously added thereto, and the esterification tank was maintained at 250 ° C. For 4 hours. After the completion of the feed, the esterification was allowed to proceed for 1 hour, and then half the amount was transferred to a polycondensation tank.
1.15 g of phosphoric acid (150 ppm to polymer) and 0.92 g of germanium dioxide (120 pp to polymer)
m), the temperature was gradually increased from 250 ° C. to 280 ° C., and the pressure was gradually reduced from normal pressure, and the pressure was maintained at 0.5 Torr. After performing the reaction for 3 hours, the CT amount was 0.93% by weight,
A copolymerized polyester chip (prepolymer chip) having an intrinsic viscosity of 0.54 dl / g was obtained.

Next, the surface of the prepolymer chip was crystallized at 150 ° C. with a stirring crystallization machine (manufactured by Bepex), and then transferred to a stationary solid-state polymerization tower under a nitrogen flow of 201 / kg-hr. After drying at 140 ° C for 3 hours,
Solid phase polymerization was performed for a time to obtain a solid phase polymerization chip. Table 1 shows the physical properties of the chip.

Next, using the chip subjected to the above solid phase polymerization treatment, a cylinder and a nozzle temperature of 270 ° C., a screw rotation speed of 100 rpm, an injection time of 10 seconds, and a mold cooling water temperature of 10 ° C. were manufactured by Toshiba Corporation. Injection molding machine IS-6
A preform was molded at 0B. After the plug portion of this preform was heated and crystallized by a self-made crystallizer, a preheating furnace temperature of 90 ° C., a blow pressure of 20 kg / cm ² , and a molding cycle 1 were used.
Blow molding was performed with a stretch blow molding machine set at 0 seconds to form a bottle having an average body thickness of 300 μm and an internal volume of 11, followed by 1 bottle.
In a mold set at 50 ° C., heat fixation was performed for 10 seconds under pressure and air tension. Table 1 shows the physical property values of the bottle. Also, 100
Zero bottles were continuously molded, and no contamination was observed in any of the injection, blowing, and heat setting molds.

Further, the orange juice liquid sterilized at 90 ° C. and allowed to cool to 85 ° C. was filled in the above-mentioned bottle, and the bottle was inverted for 15 minutes after sealing. No change was observed.

Example 2 From the solid-state polymerization tip of Example 1, the temperature of each part of the cylinder and nozzle was set to 275 ° C., and the screw rotation speed was set to 40 rpm.
m, a sheet having a thickness of 1.0 mm was formed with a 30 mmφ extruder set at an extrusion discharge rate of 100 g / min. The density of the sheet is 1.33, yield strength 560 kg / cm ^2, a breaking strength of 715kg / cm ^2, CT amount was 0.4 / wt%. At this time, the sheet was continuously extruded for 10 hours, but no contamination on the surface of the cooling drum was observed.

The raw sheet was pressed using a pressurized air vacuum forming machine (manufactured by Asano Laboratory Co., Ltd.) set at a sheet temperature of 120 ° C., a pressurized air of 4.0 kg / cm ² , a vacuum of 500 mmHg, and a cooling mold of 40 ° C. A sheet-shaped thin container was manufactured. The container piece has a yield strength of 570 kg / cm ² and a breaking strength of 720 k.
g / cm ² , and the physical properties are shown in Table 1. The same mechanical strength as that of the PET thin container of Comparative Example 4 was exhibited.
The T amount showed a significant decrease.

Example 3 5.74 kg of ethylene glycol and 0.43 kg
The esterification was carried out in the same manner as in Example 1, except that 1,4-cyclohexanedimethanol (cis / trans = 3/7) was used. Half the amount was transferred to a polycondensation tank, and 1.74 g
The polycondensation reaction was carried out in the same manner as in Example 1 except that antimony trioxide (based on 225 ppm of polymer) was used to obtain a prepolymer having a CT amount of 0.94% by weight and an intrinsic viscosity of 0.55 dl / g. Next, solid-state polymerization was performed at 210 ° C. for 20 hours in the same manner as in Example 1. Table 1 shows the physical properties of the solid-phase polymerization chip.
It is shown in FIG.

Using this tip, the temperature of each part of the cylinder and nozzle was set to 275 ° C., and the screw rotation speed was set to 40 rpm.
m, a sheet having a thickness of 300 μm was formed using a 30 mmφ extruder set at an extrusion rate of 80 g / min. Extrusion was continued for 10 hours continuously, and almost no contamination of the cooling drum was observed. Further, the extruded sheet was 3 × 3 in a long stretching machine (manufactured by TM Long) set at 90 ° C. in a tank.
After biaxial stretching at the same time, stretch in an oven under tension.
It was heat-set at 0 ° C. for 120 seconds to obtain a stretched film having a thickness of 100 μm. Table 1 shows the physical properties of the film.

Example 4 7.5 kg of dimethyl terephthalate, 4.66 kg of ethylene glycol, 0.25 kg of 1,4-cyclohexanedimethanol (cis / trans 4/6) and 1.39 g of manganese acetate tetrahydrate were placed in a reaction vessel. Charged, the temperature was gradually raised from 160 ° C. to 220 ° C. over 4 hours to carry out esterification. To this reaction product, 1.50 g of phosphoric acid and 0.90 g of germanium dioxide were added, and finally, at 275 ° C. and 0.5 torr under a polymerization time of 3 hours, the CT amount was 0.87% by weight and the intrinsic viscosity was 0.60 dl. / G of prepolymer.
Next, solid-state polymerization was performed at 210 ° C. for 20 hours in the same manner as in Example 1. Table 1 shows the physical properties of the solid-phase polymerization chip. In the same manner as in Example 1, a 1-liter heat-fixed bottle was obtained from the chip. Table 1 shows the physical properties of the bottle. Example 1
No contamination of the mold was observed even after continuous operation in the same manner as in the above. Further, no change was observed in the bottle in the hot filling test performed in the same manner as in Example 1.

Comparative Example 1 A prepolymer having a CT amount of 1.01% by weight and an intrinsic viscosity of 0.55 dl / g was obtained in the same manner as in Example 1 except that 1,4-cyclohexanedimethanol was not added. .
Next, solid-state polymerization was performed at 210 ° C. for 20 hours in the same manner as in Example 1. Table 1 shows the physical properties of the solid-phase polymerization chip. Table 1 shows the physical properties of the heat-fixing bottle having a capacity of 1 liter obtained from this chip in the same manner as in Example 1. Further, in the bottle, the result of the hot filling test similar to that in Example 1 was good, but when the mold after molding was observed as a continuous molding test, a thin white film-like deposit was observed.

Comparative Example 2 5.57 kg of ethylene glycol and 1,4-cyclohexanedimethanol (cis / trans: 3/7)
The same operation as in Example 1 was carried out except that 81 kg was used.
A prepolymer of 0.80% by weight of the amount and an intrinsic viscosity of 0.54 dl / g was obtained. Next, in the same manner as in the first embodiment, 210
Solid-state polymerization was performed at 20 ° C for 20 hours. Table 1 shows the physical properties of the solid-phase polymerization chip. From this chip, the same operation as in Example 1 was performed to produce a 1-liter heat-fixed bottle. Table-Physical properties of the bottle
It is shown in FIG. In a continuous molding test similar to that in Example 1,
Almost no contamination of the mold was observed, but a hot filling test showed that the entire bottle was deformed and a small amount of liquid leaked from the plug.

Comparative Example 3 The procedure of Example 1 was repeated, except that 0.35 kg of diethylene glycol (DEG) was added to the prepared slurry.
A prepolymer having a CT amount of 0.83% by weight and an intrinsic viscosity of 0.58 dl / g was obtained. Next, in the same manner as in the first embodiment, 21
Polymerization was carried out at 0 ° C. for 20 hours. Table 1 shows the physical properties of the polymerized chips.
Shown in 1 l obtained from this chip in the same manner as in Example 1.
Table 1 shows the physical properties of the heat-fixed bottle. Further, in the continuous molding test, a thin white film was found to adhere to the surface of the mold.
Further, in the hot filling test, deformation of the bottle and leakage of liquid from the spout were observed.

Comparative Example 4 Using the solid-state polymerization chip produced in Comparative Example 1, the same operation as in Example 2 was carried out to produce a sheet-shaped thin container. The container has a yield strength of 580 kg / cm ² and a breaking strength of 720 k.
g / cm ² and other physical properties are shown in Table 1. During the production of a raw sheet by continuous extrusion for 10 hours in the same manner as in Example 3, white powder-like deposits were observed on the surface of the cooling drum.

Comparative Example 5 A biaxially stretched film was produced in the same manner as in Example 3, except that 1,4-cyclohexanedimethanol was not used. Table 1 shows the physical properties of the solid-phase polymerization chip. Further, at the time of production of a raw material by continuous extrusion molding for 10 hours performed in the same manner as in Example 3, slight white powder-like deposits were observed on the surface of the cooling drum.

[0043]

[Table 1]

[0044]

The copolymerized polyester of the present invention has a low oligomer content and does not easily cause mold contamination during molding. Therefore, it is not necessary to frequently clean the molding apparatus when producing a molded product, so that the productivity of molded products such as bottles, films, and sheets can be improved. Moreover, the copolymerized polyester of the present invention is excellent in heat resistance, mechanical strength, and the like, and is particularly suitable as a molding material for a fruit juice beverage container or the like that requires heat resistance.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-200832 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (5)

(57) [Claims] 1. A copolymerized polyester containing terephthalic acid as a dicarboxylic acid component and ethylene glycol as a diol component, and (1) cyclohexanedimethanol as a diol component in an amount of 0.1 to 5.0.
Mol%, 0.2 to 3.0 mol% of diethylene glycol
And (2) the content of the cyclic trimer is 0.35% by weight.
Hereinafter, (3) intrinsic viscosity is 0.50 to 1.50 dl /
g, (4) Density is 1.37 g / cm ³ or more, (5)
Low temperature crystallization peak temperature (T
c) 120 to 185 ° C. 2. A hollow container made of a copolyester obtained by forming a preform from the copolyester according to claim 1 by injection molding or extrusion molding and then biaxially stretch blow molding. 3. A sheet obtained by injection molding or extrusion molding the copolymerized polyester according to claim 1. 4. A container made of a copolyester formed by molding the sheet material according to claim 3. 5. A stretched film made of a copolyester obtained by stretching the sheet-like material according to claim 3 in at least one direction.