JP2003327680A - Crystallization method for copolymerized polyester resin - Google Patents

Abstract

(57) [Summary] [Purpose] The polyester resin after melt polycondensation is dried,
In the heat crystallization treatment prior to subjecting to solid-phase polycondensation or molding, etc., fusion of the polyester resin granules can be suppressed, and uniform and efficient crystallization can be achieved without a decrease in molecular weight. And a method for crystallizing a copolymerized polyester resin. The sum (A +) of the mole% of dicarboxylic acid components other than terephthalic acid or its ester-forming derivative (A) with respect to all dicarboxylic acid components and the mole% of diol components other than ethylene glycol (B) with respect to all diol components (A +
B) is more than 20 to 80, and a copolymerized polyester resin having an ethylene terephthalate unit as a main constituent repeating unit is subjected to heat crystallization treatment after moisture conditioning to a water content of 0.10 to 2.0% by weight. A method for crystallizing a polymerized polyester resin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for crystallizing a copolyester resin, more specifically, heating the polyester resin after melt polycondensation prior to subjecting it to drying, solid phase polycondensation, molding or the like. In the crystallization process,
The present invention relates to a method for crystallizing a copolyester resin capable of suppressing fusion between polyester resin granules and uniformly and efficiently crystallizing the same.

[0002]

2. Description of the Related Art Conventionally, polyester resins, typically polyethylene terephthalate resins, have excellent mechanical strength, chemical stability, transparency, gas barrier properties, safety and hygiene, and are relatively inexpensive and lightweight. For this reason, it is widely used as films, fibers, bottles, etc., and a homopolyethylene terephthalate resin composed of terephthalic acid or its ester-forming derivative as a dicarboxylic acid component and ethylene glycol as a diol component has high crystallinity. However, in view of poor moldability due to its high melting point and being too rigid depending on the application, for example, dicarboxylic acid components such as isophthalic acid and diol components such as butanediol and cyclohexanedimethylol are used together. It is used as a polymerization component to improve molding processability or to give flexibility and other properties. Ethylene terephthalate resins have also been used in the field of films or sheets suitable for the respective characteristics.

On the other hand, the polyethylene terephthalate resin undergoes an esterification reaction or a transesterification reaction between a dicarboxylic acid component containing terephthalic acid or its ester-forming derivative as a main component and a diol component containing ethylene glycol as a main component, After melt polycondensation in the presence of a polycondensation catalyst, it is usually dried, or heated to further increase the degree of polymerization and solid-phase polycondensed, and then subjected to molding. The resin is subjected to a heat crystallization treatment prior to drying or solid phase polycondensation, and in the crystallization treatment, the copolymer resin as described above has a low crystallinity as compared with a homopolymer resin, Due to the low melting point and the like, fusion between the resin particles often occurs, which not only lowers working efficiency but also hinders uniform crystallization.

On the other hand, various preventive measures have heretofore been proposed in order to prevent the fusion of resin particles with each other in the crystallization treatment. For example, in Japanese Patent Laid-Open No. 9-241360, a specific temperature and There has been proposed a method for preventing fusion by supplying water for a while to allow the water to exist on the surface of the resin particles. However, according to the study by the present inventors, this method not only has the problem that the resin causes a decrease in molecular weight due to water absorption, but the amount of water supplied by this method is 5 to 30% by weight of the total weight. Since it is necessary to use a large amount such as%, the economic disadvantages associated with it, such as equipment and water removal after the treatment, were unavoidable.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances. Therefore, the present invention provides a polyester resin after melt polycondensation for drying, solid phase polycondensation, molding or the like. In the heat crystallization treatment prior to providing, it is possible to suppress fusion between the polyester resin particles, and to uniformly and efficiently crystallize without lowering the molecular weight, and a crystallization method of a copolymerized polyester resin. The purpose is to provide.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above object can be achieved by adjusting the water absorption of a resin to a specific range. The present invention is completed, that is, in the present invention, the mol% (A) of the dicarboxylic acid component other than terephthalic acid or its ester-forming derivative is based on the total dicarboxylic acid component.
And a sum (A + B) of the mol% (B) of diol components other than ethylene glycol to the total diol component is more than 20 to 80, and a copolymerized polyester resin having an ethylene terephthalate unit as a main constitutional repeating unit,
A crystallization method of a copolyester resin, in which a moisture content is adjusted to 0.10 to 2.0% by weight, and then heat crystallization is performed, is a gist.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester resin in the method for crystallizing a copolyester resin of the present invention comprises terephthalic acid or its ester-forming derivative as a dicarboxylic acid component, ethylene glycol as a diol component, and ethylene glycol as a main component. The sum (A + B) of the mol% (A) of the dicarboxylic acid component other than terephthalic acid or its ester-forming derivative to the dicarboxylic acid component and the mol% (B) of the diol component other than ethylene glycol to the total diol component exceeds 20. To 80, a dicarboxylic acid component and a diol component are melted and polycondensed in the presence of a polycondensation catalyst through an esterification reaction or a transesterification reaction, and an ethylene terephthalate unit as a main constituent repeating unit is produced. Is preferably a copolyester resin But the range of the polyester resin comprising a dicarboxylic acid component and a diol component, the molar% of terephthalic acid or dicarboxylic acid component other than an ester-forming derivative thereof (A) to the total dicarboxylic acid components,
Sum (A + B) of mol% (B) other than ethylene glycol to all diol components exceeds 20
A melt-kneaded product having a weight ratio of 80 is also included.

Here, mol% (A) of the dicarboxylic acid component other than terephthalic acid or its ester-forming derivative relative to the total dicarboxylic acid component and mol% (B) of the diol component other than ethylene glycol relative to the total diol component. The sum (A + B) is preferably 22 to 70, and 23
More preferably, it is -60. In addition, "the ethylene terephthalate unit is the main constituent repeating unit" means
This means that the ethylene terephthalate unit is the most abundant in all the constitutional repeating units, and the ethylene terephthalate unit preferably constitutes 30 to 80 mol% of the constitutional repeating unit, more preferably 50 to 80 mol%.

Here, examples of the ester-forming derivative of terephthalic acid include alkyl esters having about 1 to 4 carbon atoms, and halides. Examples of the dicarboxylic acid copolymerization component other than terephthalic acid or its ester-forming derivative include phthalic acid, isophthalic acid, phenylenedioxydicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid. Acid, 4,4'-diphenylketone dicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,
Aromatic dicarboxylic acids such as 4′-diphenylsulfone dicarboxylic acid and 2,6-naphthalenedicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, and succinic acid, glutaric acid, adipic acid, Aliphatic dicarboxylic acids such as pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid, and dodecadicarboxylic acid, and alkyl esters having about 1 to 4 carbon atoms thereof, and halides, and the like, Among these, in the present invention, isophthalic acid, 2,6-
Naphthalenedicarboxylic acid, and ester-forming derivatives thereof are preferred.

Examples of diol copolymer components other than ethylene glycol include trimethylene glycol,
Tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol, diethylene glycol, polyethylene glycol,
Aliphatic diols such as polytetramethylene ether glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, alicyclic diols such as 1,4-cyclohexanedimethylol, and xylyl Len glycol, 4,4'-dihydroxybiphenyl, 2,2-bis (4'-hydroxyphenyl) propane, 2,2-bis (4'-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone , Aromatic diols such as bis (4-β-hydroxyethoxyphenyl) sulfonic acid, and the like. Among them, in the present invention, diethylene glycol, tetramethylene glycol, cyclohexane dimethylol and the like are preferable.

Further, for example, hydroxycarboxylic acids and alkoxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid, and
Monofunctional components such as stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid, tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane, and trimethylolethane. A trifunctional or higher polyfunctional component such as methylolpropane, glycerol, or pentaerythritol may be used as a copolymerization component.

The production of the copolymerized polyester resin in the present invention is basically carried out by a conventional production method of polyester resin. That is, terephthalic acid or its ester-forming derivative and ethylene glycol are charged together with the copolymerization component into a slurry preparation tank and mixed under stirring to form a raw material slurry, which is then transferred to an esterification reaction tank, or
Alternatively, at that time, a part of the raw material is directly charged into the esterification reaction tank, and the esterification reaction or transesterification reaction is carried out under normal pressure to increased pressure and heating in the esterification reaction tank, and then the obtained esterification is carried out. The low molecular weight polyester as a reaction product or a transesterification reaction product is transferred to a polycondensation tank and melt-polycondensed in the presence of a polycondensation catalyst under atmospheric pressure from a reduced pressure as a gradual reduced pressure and under heating. In addition, these may be a continuous type or a batch type, and the esterification reaction tank and the polycondensation tank may each have one stage or multiple stages.

The raw material slurry is usually prepared by terephthalic acid or its ester-forming derivative and ethylene glycol together with the above-mentioned copolymerization component, and the molar ratio of the diol component to the dicarboxylic acid component is preferably 1.0.
5 to 3.0, more preferably 1.2 to 2.0, usually at room temperature to 100 ° C., preferably at 30 to 80 ° C., and uniformly mixed.

The esterification reaction or transesterification reaction is usually carried out in the presence of a transesterification catalyst in the case of transesterification reaction at a temperature of about 240 to 280 ° C., usually 0 to
It is carried out under a pressure of about 4 × 10 ⁵ Pa for about 1 to 10 hours with stirring, and the melt polycondensation is usually performed at a temperature of about 250 to 290 ° C. in the presence of a polycondensation catalyst and a stabilizer. As a gradual depressurization from the pressure, it is usually 1333-13.3P.
It is carried out for about 1 to 20 hours with stirring under a reduced pressure of about a.

Examples of polycondensation catalysts include germanium dioxide, germanium tetroxide, germanium hydroxide, germanium oxalate, germanium tetraethoxide, germanium compounds such as germanium tetra-n-butoxide, antimony trioxide, antimony acetate, and the like. Antimony compounds such as methoxyantimony, tetra-n-propyl titanate, tetra-i-propyl titanate,
Titanium compounds such as tetra-n-butyl titanate, titanium oxalate, and potassium titanium oxalate are used.

At the time of polycondensation, phosphorus compounds such as orthophosphoric acid, tris (triethylene glycol) phosphate, ethyl diethylphosphonoacetate, ethyl acid phosphate, triethylene glycol acid phosphate and phosphorous acid are stabilized together with the polycondensation catalyst. It is preferable to coexist as an agent.

These polycondensation catalysts and stabilizers may be added to the reaction system at any stage of the slurry preparation process, the esterification reaction or transesterification reaction process, or at the initial stage of the melt polycondensation process. However, the stabilizer is preferably added to the slurry preparation tank, and
The polycondensation catalyst is preferably added to the esterification reaction tank (the final reaction tank in the case of multiple stages), a pipe for transferring the esterification reaction product to the polycondensation tank, or the polycondensation tank.

The melt-polycondensed resin is usually withdrawn in a strand form from an outlet provided at the bottom of the polycondensation tank and cut into pellets, chips or the like while being cooled with water or after water cooling and then cut with a cutter. It is made into a granular body. In the present invention, the average weight per grain of the granules is preferably in the range of 10 to 500 mg in view of the humidity control property described later in the present invention.

The resin particles after the melt polycondensation are heated and crystallized before being subjected to subsequent drying, solid phase polycondensation, molding or the like. The drying is preferably performed under dehumidified air or dry nitrogen, preferably at 90 to 160 ° C.,
More preferably, it is dried under heating at 100 to 150 ° C. until the water content of the resin granules is preferably 0.05% by weight or less, more preferably 0.03% by weight or less.
In addition, the solid phase polycondensation is an inert gas such as nitrogen, carbon dioxide or argon for the purpose of further increasing the degree of polymerization of the polyester resin and reducing the reaction by-products such as cyclic trimers. It is carried out at a temperature of 190 to 230 [deg.] C., preferably 195 to 225 [deg.] C. under a gas atmosphere under atmospheric pressure.

In the heat crystallization treatment in the crystallization method of the copolyester resin of the present invention, the melt-polycondensed granular material is dried or under an atmosphere of an inert gas such as nitrogen, carbon dioxide or argon. Alternatively, in a water vapor atmosphere or in a water vapor-containing inert gas atmosphere, preferably in a temperature range of 10 ° C. higher than the glass transition point of the resin to 150 ° C., more preferably in a temperature range of 140 ° C. The surface of the resin particles is crystallized by heating. The crystallization device at that time is preferably a rotary cone type dryer, a hopper type dryer with a stirrer, a horizontal cylindrical crystallization machine with a stirrer, an agitating dryer type such as an aeration rotary dryer, and a rotating cylinder. An aeration rotary drier in which hot air is passed through and agitated while being heated is particularly preferable.

In the method for crystallizing the copolymerized polyester resin of the present invention, the copolymerized polyester resin particles after melt polycondensation are treated with 0.10 to
It is essential to control the humidity to a water content of 2.0% by weight, and the water content is preferably 0.20 to 1.0% by weight.
More preferably, it is 30 to 0.50% by weight.

When the moisture content of the humidity control is less than the above range, the crystallization speed of the resin granules during the crystallization treatment is low, and it takes a long time to crystallize, so that the fusion of the resin granules easily occurs. On the other hand, if the content exceeds the above range, water will be present on the surface of the resin granules, and the water will hinder the transfer of pipes.

The humidity control is preferably carried out at a temperature of 100 ° C. or lower, more preferably 80 ° C. or lower, more preferably 60 ° C. or lower, in order to ensure fusion prevention between the resin particles. Is particularly preferable.

The method of conditioning the humidity is not particularly limited, and may be, for example, a method of immersing the resin granules in water, a method of spraying water on the resin granules, or a method after melt polycondensation. Examples thereof include a method of leaving a part of the cooling water at the time of granulation in the form of a let, a chip or the like.

The intrinsic viscosity of the resin obtained by the crystallization method of the copolyester resin of the present invention is phenol /
1,1,2,2-Tetrachloroethane (weight ratio 1/1)
0.55 as a value measured at 30 ° C. in the mixed solvent of
It is preferably 0.80 dl / g, and 0.60 to 0.
More preferably, it is 75 dl / g.

[0026]

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

Example 1 80 parts by weight of dimethyl terephthalate, 20 parts by weight of dimethyl isophthalate, and 64 parts by weight of ethylene glycol, and calcium acetate 0.09 as a transesterification catalyst.
The mixture with 0 part by weight was put into an esterification reaction tank,
Increase the temperature from 150 ° C to 240 ° C over 3 hours, then
The ester exchange reaction is carried out by holding for a time, the esterification reaction product is transferred to a polycondensation tank, and 0.040 parts by weight of orthophosphoric acid as a stabilizer and 0.040 parts by weight of antimony trioxide as a polycondensation catalyst are added. After adding
After polycondensation at 0 to 280 ° C. for 4 hours, the mixture was discharged into a water tank in a strand shape and chipped with a pelletizer to produce a copolymerized polyester resin particle having an average weight of 35 mg per particle.

The resulting copolymerized polyester resin granules are copolymerized by the following method (including diethylene glycol produced as a by-product from ethylene glycol).
The amount, intrinsic viscosity, and water content were measured, and the results are shown in Table 1.

<Amount of Copolymerization Component> A solution prepared by dissolving a resin sample in trifluoroacetic acid was analyzed by using a nuclear magnetic resonance apparatus (“JNM-EX270” manufactured by JEOL Ltd.) for ¹ H-
Each peak was assigned by measuring NMR, and from the integrated value of the peaks, the mol% of the dicarboxylic acid component other than terephthalic acid or its ester-forming derivative was based on the total dicarboxylic acid component.
(A) and the mol% (B) of the diol components other than ethylene glycol with respect to all the diol components were calculated, and the sum (A + B) was calculated.

<Intrinsic viscosity> Resin sample is phenol / 1,
After it was dissolved in a mixed solvent of 1,2,2-tetrachloroethane (weight ratio 1/1) at 110 ° C, it was cooled to 30 ° C,
It measured at 30 degreeC using the Ubbelohde type viscometer.

<Water content> An aluminum cup having an inner diameter of 80 mm and a height of 25 mm was weighed with a hot air electric constant temperature dryer (“DSF-11S type” manufactured by Isuzu Seisakusho Co., Ltd.) for 140
It was dried at ℃ for 2 hours, left in silica gel desiccator for 1 hour, weighed [A (g)], then about 20 g of resin sample was put into the aluminum cup and weighed [B (g)].
After that, it was dried at 140 ° C. for 2 hours in the same dryer, left for 1 hour in a silica gel desiccator, and then weighed [C
(G)]. From the weighing results, the water content in the resin was calculated by the following formula. Moisture content (% by weight) = [(B−C) / (B−A)] × 10
0

Then, the obtained resin granules are put into a stainless steel container, and 0.40% by weight of pure water is added to the mixture to make it 3
Keep the temperature at 0 ° C for one day to make the water content of the resin granules 0.44.
After the weight%, the resin granules are continuously charged into an aeration rotary dryer so that the residence time is 1 hour, and hot air of 140 ° C. is passed through the rotating cylinder to perform crystallization while heating and stirring. did. At that time, the fusion rate between the resin particles, and the crystallinity of the obtained resin particles are measured by the method described below, and the intrinsic viscosity is measured by the same method as described above. The results are shown in Table 1.

<Fusion Rate of Resin Granules> In 100 g of the resin granules after the crystallization treatment, two or more grains are fused and connected to each other and visually selected, and the weight ratio is used as the fusion rate. did.

<Crystallinity> The degree of whitening due to crystallization of the resin granules after the crystallization treatment was visually observed and evaluated according to the following criteria in 5 grades. 1; almost all of the particles are transparent as in the uncrystallized state,
It has not been crystallized at all. 2; A state in which some of the particulates partially clouded are mixed and crystallization has started. 3; Almost all of the particles are slightly whitened. 4; A state in which slightly whitened particles are mixed in the whitened particles. 5: Almost all of the granular materials are whitened and completely crystallized.

Examples 2 to 3 and Comparative Examples 1 to 3 are shown in Table 1 in the same manner as in Example 1 except that the amounts of the dicarboxylic acid component and the diol component used and the reaction time were changed as shown in Table 1. Same as Example 1 except that a copolymerized polyester resin having an average weight per grain, a copolymerization component amount, an intrinsic viscosity, and a water content was produced, and the moisture conditioning and the crystallization treatment were further performed under the conditions shown in Table 1. The humidity was adjusted, the crystallization treatment was performed, and the fusion rate of the resin particles after the crystallization treatment, the crystallinity of the resin particles, and the intrinsic viscosity were measured, and the results are shown in Table 1.

[0036]

[Table 1]

[0037]

According to the present invention, when the polyester resin after melt polycondensation is heated and crystallized before being subjected to drying, solid phase polycondensation, molding or the like, fusion between polyester resin particles is performed. It is possible to provide a method for crystallization of a copolyester resin, which can suppress crystallization and can uniformly and efficiently crystallize without lowering the molecular weight.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J029 AA01 AA03 AB07 BA02 BA03                       BF25 CB04A CB05A CB06A                       CB10A CE04 CF03 CF15                       KH08

Claims (3)

[Claims] 1. The sum of mol% (A) of dicarboxylic acid components other than terephthalic acid or its ester-forming derivative based on all dicarboxylic acid components and mol% (B) of diol components other than ethylene glycol based on all diol components. (A + B) is in excess of 20 to 80, and a copolyester resin having an ethylene terephthalate unit as a main constitutional repeating unit is subjected to heat crystallization treatment after being conditioned to a water content of 0.10 to 2.0% by weight. A method for crystallizing a copolyester resin, comprising: 2. The method for crystallizing a copolyester resin according to claim 1, wherein the humidity control of the water content is performed at a temperature of 100 ° C. or lower. 3. The method for crystallizing a copolyester resin according to claim 1, wherein the temperature during the heat crystallization treatment is 150 ° C. or lower.