JP2000143791A - Production of modified polyethylene terephthalate resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a modified polyethylene terephthalate(PET) resin which comprises a deactivation treating step for a polycondensation catalyst in the PET resin and is improved so as to uniformly carry out the deactivation treatment. SOLUTION: When a modified PET resin is produced by feeding a PET resin containing a polycondensation catalyst in an undeactivated state to a hot water treating bath or a heating humidification treating bath and deactivating the polycondensation catalyst, the feed of the PET resin to the hot water treating bath or heating humidification treating bath is carried out by the gas power transfer and the solid gas ratio of the gas power transfer is regulated within the range of 10-30 kg/kg.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a modified polyethylene terephthalate resin, and more particularly to a method for producing a modified polyethylene terephthalate resin which is less likely to cause mold contamination during molding.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 7-37515 discloses a solid-state polymerization process in order to prevent mold contamination during blow molding of a polyethylene terephthalate (PET) resin and obtain a molded product having an excellent surface appearance. By supplying the obtained PET resin containing the polycondensation catalyst without deactivating the polycondensation catalyst to the hot water treatment tank to deactivate the polycondensation catalyst, oligomers (cyclic trimers) which are the main cause of mold contamination are obtained. The invention has been proposed in which the total amount of) is prevented from increasing during molding.

When the PET resin chips are transferred from the silo to the above-mentioned hot water treatment tank, for example, the residence time of the resin chips in the hot water treatment tank is varied in order to make the processing in the hot water treatment tank uniform. It is desired to transfer the resin chips so as to be as constant as possible.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a modified PET resin including a step of deactivating a polycondensation catalyst in the PET resin. In view of the above, it is an object of the present invention to provide the above-mentioned production method improved so that the above-mentioned deactivation treatment can be performed uniformly.

[0005]

Means for Solving the Problems The present inventor has conducted various investigations and studies in order to achieve the above object, and has obtained the following findings.

As a means for transferring a granular material such as a PET resin chip, various mechanical devices such as a screw conveyor, a bucket conveyor, and a belt conveyor are known. Excellent in terms of. That is, there is no defect that the transfer stability is excellent (quantitative) and that the chips are dropped as a lump into the hot water treatment tank as in the case of a bucket conveyor and the residence time in the tank varies.

[0007] However, in the case of using a screw conveyor, it is presumed that the PET resin chip is damaged in some way by the kneading action of the screw, but the haze deteriorates when the PET resin is injection molded into a sheet. There's a problem.

The present inventor has made further studies utilizing the above findings, and as a result, adopted the power transfer as a method of transferring the polycondensation catalyst to the deactivation treatment step, and specified the solid-gas ratio of the power transfer. It has been found that if the thickness is adjusted to the range described above, the problem of haze deterioration when a PET resin is formed into a sheet by injection molding can be solved, and the deactivation treatment can be made uniform.

The present invention has been completed on the basis of the above-mentioned various findings, and the gist of the present invention is to provide a polyethylene terephthalate resin containing a polycondensation catalyst without deactivating the polycondensation catalyst in a hot water treatment tank or a heat humidification treatment tank. In producing the modified polyethylene terephthalate resin by supplying and deactivating the polycondensation catalyst, the supply of the polyethylene terephthalate resin to the hot water treatment tank or the heating and humidification treatment tank is performed by pneumatic transfer, and the solid-gas of the pneumatic transfer is performed. The ratio is 10-3
The method for producing a modified polyethylene terephthalate resin is characterized in that it is adjusted to a range of 0 kg / kg.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the present invention, the PET resin is a polycondensate of a dicarboxylic acid unit mainly containing terephthalic acid or an alkyl (1 to 4 carbon atoms) ester thereof and a glycol unit mainly containing ethylene glycol. The proportion of the ethylene terephthalate unit in the structural repeating unit is preferably at least 80 mol%, more preferably at least 90 mol%. If the ethylene terephthalate unit is less than 80 mol%, the mechanical properties and heat resistance of the molded article tend to be poor.

Examples of the dicarboxylic acid unit other than terephthalic acid and its alkyl ester include phthalic acid and
Isophthalic acid, 4,4′-diphenyldicarboxylic acid,
4,4′-diphenoxyethanedicarboxylic acid, 4,4 ′
-Diphenyl ether dicarboxylic acid, aromatic dicarboxylic acid such as 4,4'-diphenyl sulfone dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, alicyclic dicarboxylic acid such as hexahydroterephthalic acid and hexahydroisophthalic acid, malonic acid, succinic acid One or more kinds of aliphatic dicarboxylic acids such as acid, adipic acid, azelaic acid, and sebacic acid are exemplified.

Examples of glycol units other than ethylene glycol include aliphatic glycols such as propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, and diethylene glycol. Alicyclic glycols such as 1,1-cyclohexanedimethanol and 1,4-cyclohexanedimethanol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-hydroxyphenyl) propane, 2,2-bis ( One or more aromatic glycols such as 4′-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, and bis (4-β-hydroxyethoxyphenyl) sulfonic acid are exemplified. .

Further, as copolymerization components, for example, hydroxycarboxylic acids such as p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid, alkoxycarboxylic acids, stearic acid, benzoic acid, stearyl alcohol,
Monofunctional components such as benzyl alcohol, trimellitic acid,
One or two or more trifunctional or higher polyfunctional components such as pyromellitic acid, trimethanolethane, and pentaerythritol may be used.

The dicarboxylic acid unit is preferably isophthalic acid, and the glycol unit is preferably diethylene glycol or 1,4-cyclohexanedimethanol, each of which is preferably within 15 mol%.
More preferably, it is used within a range of 5 mol% or less.

The polymerization is carried out as follows. First, in the presence of an esterification catalyst or a transesterification catalyst such as a metal compound (such as a manganese compound), a temperature of 240 to 280 ° C.
An esterification reaction or transesterification reaction is performed at a pressure of ３3 kg / cm ² G to obtain bis (β-hydroxyethyl) terephthalate and / or an oligomer thereof.

Then, in the presence of a polycondensation catalyst such as a germanium compound or an antimony compound and a stabilizer such as a phosphorus compound (such as phosphoric acid), the temperature is from 250 to 300 ° C.
The polymer is obtained by performing melt polycondensation at a pressure of 0.1 mmHg. Then, after being extracted in a strand shape from an extraction port provided at the bottom of the melt polycondensation tank, it is cut into a chip shape by a cutter.

Thereafter, if necessary, preliminary crystallization is carried out, followed by solid-phase polycondensation to obtain a chip-shaped PET resin. Usually, the pre-crystallization is performed by heating at a temperature of about 120 to 200 ° C. for 1 minute or more, and the solid-phase polycondensation is performed at a temperature of 190 to 230 ° C., 1 k
The treatment is performed at a pressure of g / cm ² G to 10 mmHg for 1 to 50 hours. P obtained through solid-state polymerization
The ET resin is particularly preferably used for a container such as a pottle.

In the above, examples of the germanium compound as the polycondensation catalyst include germanium dioxide, germanium tetroxide, germanium tetraethoxide, germanium tetra n-butoxide, etc. The content is 10
Preferably, the amount is in the range of 200 ppm.
More preferably, the amount falls within the range of 120 ppm. Examples of the antimony compound include antimony trioxide, antimony acetate, and methoxyantimony.The amount of the antimony compound used is preferably such that the content as an antimony atom in the resin is in the range of 100 to 400 ppm, More preferably, the amount is in the range of 150 to 300 ppm. In particular, the present invention is useful for a PET resin using a germanium compound as a polycondensation catalyst.

[0019] The present invention provides a method for dehydrating a polycondensation catalyst by subjecting the PET resin obtained as described above and containing the polycondensation catalyst to a state not deactivating the polycondensation catalyst by hot water treatment or heat humidification treatment. The modified PET resin is manufactured so that the mold contamination hardly occurs.

PE for hot water treatment or heat humidification treatment
As the T resin, the intrinsic viscosity (I
PET resins having a V) of 0.5 to 1.2 dl / g are preferred. In particular, in the use of a container such as a pottle, in addition to the above conditions, the density is 1.37 g / cm ³ or more, the oligomer (cyclic trimer) content is 0.5% by weight or less, and the acetaldehyde content is A PET resin having 10 ppm or less is preferable.

In the present invention, in order to produce a modified PET resin, the above-mentioned PET resin chip is supplied to a hot water treatment tank or a heating and humidification treatment tank to deactivate the polycondensation catalyst. The hot water treatment tank or the heating and humidification treatment tank is not particularly limited, but a tower type treatment tank is recommended in consideration of an advantage that the installation area can be reduced.

In a tower-type treatment tank, usually, a hot water or heated steam supply pipe is provided at the bottom of the tower, a hot water or heated steam extraction pipe is provided at the top of the tower, and a modified PET resin chip extracting valve (for example, a rotary valve or the like) is provided at the bottom of the tower. ) Is installed. Then, the PET resin chips are supplied from the tower top and extracted from the tower bottom. In the case of a hot water treatment tank, extraction of the PET resin chip is performed together with hot water. Therefore, in the case of a hot water treatment tank, a dehydrator is required as an auxiliary equipment described below, but in the case of a heating and humidification treatment tank, there is an advantage that the dehydrator can be omitted. The modified PET resin chips extracted from the bottom of the tower are sequentially processed by a dehydrator (when a hot water treatment tank is used), a heat dryer, a cooler, and the like.

The most important feature of the present invention is that the supply of the PET resin chips to the hot water treatment tank or the heating and humidification treatment tank is performed by pneumatic transfer, and the solid-gas ratio of the pneumatic transfer is 10 to 30 k.
g / kg. Here, the pneumatic transfer refers to a method of flowing a gas (air or an inert gas) into a pipe and suspending and transferring the PET resin chip in the gas flow. The basic equipment is composed of a receiving hopper for receiving PET resin chips, a flow tank connected to a lower part of the hopper, and a conveying pipe provided at a lower part of the hopper.

In the above pneumatic transfer, the PET resin chips quantitatively supplied from the receiving hopper to the flow tank are:
By the gas flow in the transport pipe, the gas is supplied to the supply hopper at the top or at the top of the tower-type treatment tank. The carrier gas is discharged out of the system via a suction blower installed near the top of the tower,
The PET resin chips are supplied from the top of the tower to the inside of the tower and are deposited.

In the above power transfer, the solid-gas ratio (solid K
g / gas Kg) is less than 10, the kinetic energy of the gas flow for transporting the PET resin chip is too small.
When the PET resin chip is deposited in a state where a mountain is formed near the center of the tower, and when the solid-gas ratio exceeds 30, the kinetic energy of the gas flow is too large. A PET resin chip is deposited in a state in which a valley is formed in the vicinity of the center. Therefore, in any case where the peaks and valleys are formed, the residence time of the chips in the tower of PET resin chips (the degree of deactivation of the polycondensation catalyst) varies. For example, in a deposition state in which a mountain is formed, the residence time of the chip at the top of the mountain is longer than that of the chip near the top and at the foot. As a result, oligomers (cyclic trimers) are formed with a large deviation during molding, as is clear from the examples and comparative examples described later. For example, in the continuous molding of bottles, defective products whose surface appearance is impaired due to mold contamination of oligomers are mixed in a product lot, and frequent mold cleaning is performed to prevent this. Are required, and in any case, the production stability deteriorates.

In the present invention, PET in the processing tank
The purpose of supplying chips so that the height of the resin chips deposited becomes substantially flat is to realize a piston flow (plug flow) of the chips in the processing tank to achieve a uniform residence time.
Thereby, variation in the reaction (deactivation reaction of the polycondensation catalyst) is prevented.

FIG. 1 shows the solid-gas ratio and oligomers (cyclic trimers) when the PET resin chips are transferred to the hot water treatment tank by power.
5 is a graph showing the relationship between the measured value and the deviation of the measured values, which was created based on the results of Examples and Comparative Examples (hydrothermal treatment) described later. As shown in FIG. 1, the deviation rapidly rises outside the solid-gas ratio defined in the present invention, and the piston-flow of the chips in the processing tank is adjusted by adjusting the solid-gas ratio at the time of power transfer to a specific range. It is surprising that (plug flow) is realized and the residence time is made uniform.

The deactivation treatment of the polycondensation catalyst in the present invention comprises
Batch, continuous, and semi-continuous methods can be used, but as described above, from the viewpoint of realizing a piston flow in order to achieve a uniform residence time, a tower-type hot water treatment tank Alternatively, a method of using a heating and humidification treatment tank and bringing the PET resin chip supplied by pneumatic transfer into contact with hot water or heated steam in a countercurrent manner in the tower is most preferred.

In the present invention, the above-mentioned treatment with hot water or heated steam is performed at a temperature of 70 to 130 ° C. (temperature of hot water or heated steam) for a period of 3 minutes to 24 hours (residence time).

On the other hand, the temperature of the PET resin chips supplied to the hot water treatment tank or the heating and humidification treatment tank is not particularly limited, but is preferably in the range of 5 to 100 ° C. When the temperature of the resin chip is lower than 5 ° C., not only the rate of the deactivation reaction of the polymerization catalyst becomes slow, but also the temperature difference between the hot water or the heated steam becomes too large, so that the heat supplied to the processing tank is reduced. There is a tendency that uneven flow occurs in the flow of water or heated steam and the deactivation reaction of the polycondensation catalyst varies. When the temperature of the resin chip exceeds 100 ° C., the IV decreases due to the progress of hydrolysis. Therefore, for example, when the temperature of the PET resin chips stored in the silo in winter is less than 5 ° C., the temperature of the PET resin chips supplied to the hot water treatment tank or the heating and humidification treatment tank by the heat retaining means or the heating means. Is preferably increased to the above range.

The dehydrator for treating the PET resin chips discharged from the hot water treatment tank is not particularly limited, and examples thereof include a centrifugal dehydrator, a vibrating sieve dehydrator, and a dryer dehydrator. It is preferable to use a viscous separation type dehydrator. A pneumatic separation type dehydrator basically includes a pipe having a plurality of bent portions and a plurality of water holes on a side wall, and an air blowing nozzle disposed at each bent portion of the pipe. Has a structure housed inside. Then, the resin chip slurry is supplied from one end of the pipe, and the dewatered resin chips are discharged from the other end of the pipe while removing water by an air flow.

In the present invention, the solid-gas ratio in the pneumatic separation type dehydrator is preferably adjusted to a range of 2 to 10 kg / m ³ . When the solid-gas ratio is less than 2 kg / m ³ , the air is insufficient, and when it exceeds 10 kg / m ³ , the residence time of the PET resin chip is shortened due to excessive air, and the dehydration efficiency is reduced in any case. descend. Moreover, the solid-gas ratio is 10 kg / m
If it exceeds ³ , the resin chips will come into intense contact with the walls and pipes inside the dehydrator and will be damaged during transportation,
The transparency of the final product is inferior. The water content of the resin chips after the dehydration treatment is preferably 50,000 ppm or less. Note that solid-gas ratio described above, unlike the solid-gas ratio in the energy transfer described above (solid Kg / gas Kg), are represented in units of solid Kg / gas m ^3, which is energy separation dewatering machine Is a result in consideration of the fact that air after use contains water.

The transfer of the resin chips from the hot water treatment tank to the dehydrator is not particularly limited, and for example, a water flow transfer device can be appropriately used. On the other hand, it is preferable to employ the above-described pneumatic transfer method for the transfer to the heating / drying machine and the cooler or the subsequent silo. As the cooler, a hopper cooler type cooler, a heat exchange type cooler cooler, or the like is used, and the chip temperature is lowered to room temperature and stored in a silo.

The PET resin includes an antioxidant, an ultraviolet absorber, an antistatic agent, a coloring agent such as a dye and a pigment, a reinforcing material such as glass fiber, flica, mica, carbon fiber, and potassium titanate, and a particle. Diameter 0.01-10μ
m, an organic fine particle such as a silicone resin, an antiblocking agent such as an inorganic fine particle such as calcium carbonate, barium sulfate, titanium oxide, aluminum oxide, silica, kaolin, and clay; an inorganic and organic nucleating agent; a plasticizer; and a flame retardant. , A flame retardant aid and the like.

The modified PET resin obtained by the above method is
For example, it is formed into a film or a sheet by extrusion, or formed into a preform by injection molding, and then formed into a bottle or the like by stretch blow molding. As the molding conditions, any known conditions can be adopted. Extrusion molding is performed, for example, at a cylinder temperature of 240-3.
It can be carried out under the conditions of 00 ° C., screw rotation speed 40 to 300 rpm, and cooling drum temperature 5 to 60 ° C. Injection molding includes, for example, a cylinder temperature of 260 to 300 ° C., a mold temperature of 5 to 40 ° C., and a screw rotation speed of 40 to 300 rpm.
m, and an injection pressure of 40 to 140 kg / cm ² . In the stretch blow molding, for example, a stretching temperature of 70 to 120 ° C. and a longitudinal stretching ratio of 1.5 to
The molding is performed under the conditions of 3.5 times and the elongation ratio in the circumferential direction of 2 to 5 times, and further, heat fixing is performed at a temperature of 100 to 200 ° C. for several seconds to several minutes.

In the present invention, the above modified PET resin is
Although the crystallization temperature after forming the molded body can be increased, specifically, the temperature-rise crystallization temperature of the molded resin composition measured by a differential scanning calorimeter is 140 to 195 ° C. Is preferred. Here, the elevated crystallization temperature refers to the top temperature of the crystallization peak observed during the course of heating from room temperature to 285 ° C. at a rate of 20 ° C./min using a differential scanning calorimeter. . Further, it is preferable that the haze of a molded sheet having a thickness of 5 mm injection-molded at a molding temperature of 280 ° C. is 15% or less.

The above-mentioned modified PET resin is particularly suitable for molding a bottle by a blow molding method such as a cold parison method in which a preform obtained by an injection molding method is reheated and then biaxially stretched. For example, it is suitably used as a container for carbonated drinks, fruit juice drinks, alcoholic drinks, drinks such as tea and mineral water, liquid seasonings such as soy sauce, sauces, mirin, and dressings, edible oils, liquid detergents, cosmetics, and the like.

[0038]

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. The evaluation methods and physical property measurement methods adopted in the following examples are as follows.

(1) Intrinsic viscosity (IV): 30 in a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1)
Measured in ° C.

(2) Cyclic trimer (CT) content: 200 mg of a polyethylene terephthalate resin sample was subjected to chloroform / hexafluoroisopropanol (volume ratio: 3/2).
The mixture was dissolved in 2 ml of the mixed solution, and further diluted with 20 ml of chloroform. A sample was reprecipitated by adding 10 ml of methanol thereto, followed by filtration to obtain a filtrate. After the filtrate was evaporated to dryness, a solution obtained by dissolving the residue in 25 ml of dimethylformaldehyde was analyzed and quantified by liquid chromatography.

(3) Acetaldehyde (AA) content:
A sample of 5.0 g was weighed, sealed in a 50-ml internal volume micro-bomb with 10 ml of distilled water under a nitrogen seal,
Extraction by heating at 160 ° C. for 2 hours was performed, and the extract was analyzed and quantified by gas chromatography using a sample as a sample.

(4) Heating crystallization temperature of sheet (Tc)
1): The sheet obtained by the method described below was measured by a differential scanning calorimeter ("DSC220C" manufactured by Seiko Instruments Inc.).
The temperature was raised from room temperature to 285 ° C. at a rate of 20 ° C./min, and the crystallization peak top temperature (Tc1
Abbreviation).

(5) Haze of sheet: A sheet obtained by the method described below was measured with a haze meter ("NDH-300A" manufactured by Nippon Denshoku Co., Ltd.).

(6) Surface appearance of the bottle: The surface appearance of the bottle was visually observed and evaluated according to the following criteria.

[0045]

[Table 1] A: Surface is smooth and no abnormality. Δ: The surface is smooth, but the smoothness is slightly inferior. ×: Adhesion of foreign matter is observed on the surface.

Example 1 13.0 parts by weight of terephthalic acid and ethylene glycol
A slurry consisting of 82 parts by weight was fed to a polycondensation tank, and an esterification reaction was carried out at 250 ° C. under normal pressure to prepare bis (β-hydroxyethyl) terephthalate and a low polymer thereof having an esterification reaction rate of 95%. , Orthophosphoric acid 0.0012
Parts by weight and 0.0012 parts by weight of germanium dioxide were added, and polycondensation was performed at 280 ° C. under a reduced pressure of 1 mmHg. The produced polymer was drawn out into a strand shape from a draw-out port provided directly at the bottom of the polycondensation bath directly connected to the cooling water bath, cooled with water, and then cut into chips.

Subsequently, the obtained polymer chips were transferred to a stirring crystallization machine (Bepex), and the surface of the polymer chips was crystallized at 150 ° C .;
At 300 ° C. for 3 hours, then transferred to a stationary solid-state polymerization tower, and subjected to solid-state polymerization at 210 ° C. for 20 hours under nitrogen flow to form chip-shaped P.
An ET resin (IV: 0.74) was produced.

The obtained PET resin chip was transferred to a drying tower, and the chip temperature was kept at 90 ° C. for 5 hours under a nitrogen flow.

[0049] By virtue of the air-fuel transfer at a solid-gas ratio of 10 kg / kg,
10 parts by weight of the above-mentioned temperature-adjusted resin chips were charged into a SUS304 tower-shaped hot water treatment apparatus having a diameter of about 2.0 m, a height of about 5.0 m, and a wire mesh attached to a lower portion thereof, and the temperature of 90 ° C. After hot water was introduced at a rate of 100 liters per hour for 4 hours to contact and deactivate the polycondensation catalyst, the modified resin chip surface was passed through a pneumatic separation type dehydrator (solid-gas ratio of 5 kg / m ³ ). After removing adhering water, it was dried at 60 ° C. for 24 hours to remove moisture absorbed.

After the chips were dried in a vacuum dryer at 130 ° C. for 10 hours, an injection molding machine (“M-7” manufactured by Meiki Seisakusho) was used.
0A "), a sheet having a thickness of 5 mm was injection-molded 1000 times continuously under the conditions of a temperature of 280 ° C. of each part of the cylinder and the nozzle head, a screw rotation speed of 200 rpm, a mold temperature of 10 ° C., and a cycle of 73 seconds. The cyclic trimer content of the molded plate obtained every 50 moldings under the above conditions was measured, and the average and deviation were calculated.

On the other hand, after the chips were dried at 130 ° C. for 10 hours using a vacuum dryer, an injection stretch blow molding machine (Nissei A
With SB Machine Co., Ltd. “ASB-50TH”), cylinder temperature 280 ° C., screw rotation speed 120 rpm,
Primary pressure time 1.0 second, blow pressure 5-30kg / c
m ² , a mold temperature of 160 ° C., an outer diameter of about 100 mm,
A bottle having a height of about 300 mm, an average wall thickness of 370 μm, an internal capacity of 1.5 L, and a weight of about 60 g was formed. And
The bottle was molded 1,000 times under the same conditions, and the surface appearance of the bottle molded in the final round was subjected to visual observation.

Table 2 shows the measurement and evaluation results of the physical properties of the modified PET resin chip, sheet and potl obtained by the above method.
To # 6.

Examples 2 to 15 and Comparative Examples 1 to 10 Modified PET resin chips in the same manner as in Example 1 except that the solid-gas ratio and the chips were changed as shown in Tables 2 to 6. Was manufactured and physical properties were measured. The results are shown in Tables 2 to 6.

[0054]

[Table 2]

[0055]

[Table 3]

[0056]

[Table 4]

[0057]

[Table 5]

[0058]

[Table 6]

Examples 16 to 30 and Comparative Examples 11 to 20 In each of the above Examples, the modified PET was treated in the same manner except that the heating steam treatment was performed using a heating humidification treatment tank instead of the hot water treatment tank. A resin was manufactured and physical properties were measured. The results are shown in Tables 7 to 11.

[0060]

[Table 7]

[0061]

[Table 8]

[0062]

[Table 9]

[0063]

[Table 10]

[0064]

[Table 11]

Comparative Example 21 A modified PET resin was produced in the same manner as in Example 1 except that the transfer of the PET resin chips to the hot water treatment tank was carried out by a screw conveyor instead of the power transfer. Then, physical properties were measured. Table 12 shows the results.

[0066]

[Table 12]

[0067]

According to the present invention described above, there is provided a method for producing a modified polyethylene terephthalate resin capable of obtaining a molded article having excellent surface appearance while eliminating mold contamination during molding and improving production stability. It is possible to provide.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the solid-gas ratio and the deviation of measured values of oligomers (cyclic trimers) when a PET resin chip is transferred to a hot water treatment tank by power.

Claims (3)

[Claims] 1. A modified polyethylene terephthalate resin is produced by supplying a polyethylene terephthalate resin containing a polycondensation catalyst without deactivating the polycondensation catalyst to a hot water treatment tank or a heating and humidification treatment tank to deactivate the polycondensation catalyst. Wherein the supply of the polyethylene terephthalate resin to the hot water treatment tank or the heat humidification treatment tank is performed by power transfer, and the solid-gas ratio of the power transfer is adjusted to a range of 10 to 30 kg / kg. A method for producing a terephthalate resin. 2. A tower type hot water treatment tank or heating humidification treatment tank is used, and polyethylene terephthalate resin supplied by pneumatic transfer is brought into countercurrent contact with hot water or heated steam in the tower. The production method described in 1. 3. The temperature of the polyethylene terephthalate resin supplied to the hot water treatment tank or the heating and humidification treatment tank is 5-10.
The method according to claim 1, wherein the temperature is adjusted to a range of 0 ° C. 4.