JP5929113B2 - Polyester resin - Google Patents

Description

  The present invention relates to a polyester resin that is excellent in transparency and easy to control crystallization, and more particularly relates to a polyester resin that uses an aluminum compound and a phosphorus compound as catalyst main components.

  Polyesters typified by polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc. are excellent in mechanical properties and chemical properties. Used in a wide range of fields such as textiles for clothing and industrial materials, films and sheets for packaging, magnetic tape, optics, bottles that are hollow molded products, casings for electrical and electronic components, and other engineering plastic molded products Has been. In particular, bottles made of saturated polyesters such as PET are excellent in mechanical strength, heat resistance, transparency and gas barrier properties, so that they are used as containers for filling beverages such as juices, carbonated drinks and soft drinks, and containers for eye drops and cosmetics. Widely used.

  Conventionally, antimony or germanium compounds have been widely used as the polyester polycondensation catalyst used in such polycondensation of polyester. Antimony trioxide is an inexpensive catalyst with excellent catalytic activity. However, if it is used in an amount of such a main component, that is, a practical polymerization rate, metal antimony is used during polycondensation. Therefore, there is a problem that darkening and foreign matters are generated in the polyester, and a polyester that does not contain antimony at all or does not contain antimony as a main catalyst component is desired.

Note that the above-mentioned foreign matter in the polyester causes the following problems.
(1) The foreign matter in the polyester for fibers causes the base stain at the time of spinning, and at the same time, reduces the strength of the product fiber itself.
Therefore, in the production of polyester fiber, a polyester polymerization catalyst with less generation of foreign matters is required from the viewpoint of operability and quality.
(2) In polyester for film, precipitation becomes a foreign substance in the polyester, causing not only roll stains during film formation, but also surface defects of the film.
Therefore, also in the production of a polyester film, a polyester polymerization catalyst with less generation of foreign matters is required from the viewpoint of operability and quality.
(3) Moreover, when polyester containing a foreign material is used as a raw material for a hollow molded article or the like, it is difficult to obtain a hollow molded article having excellent transparency.

As a novel polycondensation catalyst that meets the above requirements, a catalyst system comprising an aluminum compound and a phosphorus compound has been disclosed and attracted attention (for example, see Patent Documents 1 to 4).
However, there is a problem that catalyst foreign matter is generated even in a catalyst system composed of an aluminum compound and a phosphorus compound. In order to solve this problem, devising a method for adjusting the ethylene glycol solution of the aluminum compound or phosphorus compound used as a catalyst, or adding a phosphorus compound after the ester reaction is completed, thereby generating foreign matter due to the polycondensation catalyst. The technique of reducing is known (for example, refer to Patent Documents 5 and 6).

  PET is also used as a material for containers such as carbonated drinks, juices, and mineral water due to its excellent transparency, mechanical strength, heat resistance, and gas barrier properties. In particular, in heat-resistant bottles for filling the contents at high temperatures, the stopper part is heated to crystallize, and the stopper part is prevented from being deformed when it is filled with heat resistance. Is widely adopted (see, for example, Patent Documents 7 and 8).

  The plug portion crystallization technique is preferably a PET that has a high crystallization speed and can be processed at a low temperature in a short time because the time and temperature of the crystallization treatment greatly affect the productivity. On the other hand, the body part is required to be transparent even when heat treatment is performed so that the filling amount of the contents of the bottle can be visually recognized from the outside, and the mouthpiece part and the body part have contradictory characteristics. is necessary. On the other hand, if the crystallization rate is too fast or too slow, the crystallization becomes non-uniform, the plug part is distorted, the dimensions of the plug part are not as designed, and the filling liquid leaks.

  In order to achieve the optimum crystallization rate of the plug part, a product having a temperature-rising crystallization temperature (hereinafter, sometimes referred to as “Tc1”) of 150 to 170 ° C., particularly 160 to 165 ° C. is desired from the market. It is rare. As described in Patent Documents 5 and 6, the polycondensation catalyst system composed of the above aluminum compound and phosphorus compound is known to obtain a PET having a Tc1 in the above range by reducing foreign matter. In the continuous polymerization production, a technique for obtaining a stable Tc1 PET by dividing a distillate of ethylene glycol to be recycled and reused has also been proposed (see, for example, Patent Document 9).

  However, even when the above-described method is used for continuous polymerization production on a commercial scale such that production is continuously performed for several days or more at a production amount of 1 ton or more per hour, Tc1 is changed due to a change in production conditions or the like. It changed greatly and it was difficult to obtain a stable Tc1 PET.

  On the other hand, as a technique for decreasing the Tc1 of PET and increasing the crystallization speed of the plug portion, it is known that a very small amount of a crystalline resin such as polyethylene or polypropylene serving as a crystal nucleating agent is blended (for example, patent document). 10). In particular, the technique of bringing a PET chip into contact with a crystalline resin member such as polyethylene or polypropylene can easily add a ppb amount of a crystal nucleating agent resin in industrial production (see, for example, Patent Documents 11 and 12).

  However, when trying to adjust Tc1 to 160 to 165 ° C. by blending a small amount of crystalline resin into PET obtained by the techniques of Patent Documents 5, 6, 9 and the like, the crystallization temperature at the time of temperature rise is It was difficult to obtain a stable Tc1 PET resin because some Tc1 was 170 ° C. or lower.

JP 2001-131276 A JP 2001-163963 A JP 2001-163964 A JP 2002-220446 A WO2005 / 075539 JP 2005-187558 A JP 55-79237 A JP 58-110221 A JP 2006-290909 A JP-A-9-151308 JP-A-9-71639 JP 2002-249573 A

  As described above, when the polyester having Tc1 of 170 ° C. or less is used for a heat-resistant bottle, there is a problem that it is difficult to control the crystallization of the bottle stopper. Similarly to this, there is a problem that whitening occurs during heating in sheet forming. Furthermore, even if Tc1 is 170 ° C. or higher, if the crystallization temperature during cooling (hereinafter sometimes referred to as “Tc2”) is high, the crystals are fixed before being sufficiently stretched during molding, and molding is performed. I found another problem that the strength of my body might decrease. Therefore, it was found that in order to obtain a molded product having the physical properties required by the market while maintaining the transparency of the molded product high, it is necessary to control Tc2 simultaneously with Tc1.

  The main object of the present invention is to control the crystallization of the plug part when it is used in a heat-resistant bottle while maintaining the transparency of the molded body high when continuous polymerization production is performed on a commercial scale. Another object of the present invention is to provide a polyester that is easy to be peeled off and, when used in a molding sheet, is less likely to whiten during heating during molding.

  That is, the present invention is a polyester resin obtained using an aluminum compound and a phosphorus compound represented by the following chemical formula (formula A) as a catalyst, and has a crystallization temperature (Tc1) at a temperature rise of 170 ° C. or higher and a temperature drop. A polyester resin having a crystallization temperature (Tc2) of 175 ° C. or lower.

(In (Formula A), X1 and X2 each represent hydrogen, an alkyl group having 1 to 4 carbon atoms, or a monovalent or higher metal.)

In the above, the amount P (ppm) of phosphorus atoms of the total phosphorus compound including the phosphorus compound represented by the chemical formula (formula A) contained in the polyester resin and the thermal decomposition product thereof is 20 with respect to the mass of the polyester resin. It is preferable that ≦ P ≦ 65.
In the above, the ratio P / Al (molar ratio) of the aluminum atom of the aluminum compound contained in the polyester resin and the phosphorus atom of the total phosphorus compound including the phosphorus compound represented by the chemical formula (formula A) and its thermal decomposition product Is preferably 1.4 ≦ P / Al ≦ 100.
In the above, it is preferable that polyester contains 85 mol% or more of ethylene terephthalate structural units.

  The polyester resin produced according to the present invention has high transparency of the molded product, and when used in a heat-resistant bottle, it is easy to control the crystallization of the plug portion, and when used in a molding sheet. Has the advantage that it is difficult to whiten during heating during molding.

It is a top view of the stepped molding board used for evaluation of the polyester resin of this invention. It is a side view of the stepped molding board used for evaluation of the polyester resin of this invention.

The present invention will be described in detail.
The polyester resin of the present invention is a polyester resin obtained using an aluminum compound and a phosphorus compound represented by the above chemical formula (formula A) as a catalyst. Furthermore, the polyester resin of the present invention has a crystallization temperature (Tc1) at the time of temperature increase of 170 ° C. or more and a crystallization temperature (Tc2) at the time of temperature decrease of 175 ° C. or less.
Tc1 is more preferably 171 ° C. or higher, further preferably 172 ° C. or higher, particularly preferably 173 ° C. or higher, and most preferably 174 ° C. or higher. If it is less than the above, the transparency is lowered, the plug part crystallization is difficult to control, and the control width may be narrow.
In reality, the upper limit of Tc1 is preferably 195 ° C., more preferably 190 ° C., still more preferably 187 ° C., particularly preferably 186 ° C., and most preferably 185 ° C.
Tc2 is more preferably 174 ° C. or lower, further preferably 173 ° C. or lower, particularly preferably 172 ° C. or lower, and most preferably 171 ° C. or lower. When Tc2 exceeds 175 ° C., the haze of the molded body is increased, and the thick part is likely to be whitened. In practice, the lower limit of Tc2 is preferably 145 ° C, more preferably 150 ° C, even more preferably 155 ° C, particularly preferably 160 ° C, and most preferably 165 ° C.
Means for setting Tc1 to 170 ° C. or higher and Tc2 to 175 ° C. or lower will be described below. In order to increase Tc1 to 170 ° C. or higher, the temperature-time product of the polycondensation step is particularly important. In order to increase Tc2 to 175 ° C. or higher, it is important to reduce foreign matters derived from the aluminum catalyst.

1. Composition of polyester resin The polyester resin is a polyester whose main repeating unit is ethylene terephthalate, preferably a linear polyester containing 85 mol% or more of ethylene terephthalate units, more preferably 90 mol%. As described above, the linear polyester containing 95 mol% or more is particularly preferable.
The “polyester resin” referred to in the present invention includes a polyester (polyethylene terephthalate or the like) as a single chemical species and a polymerization catalyst or a decomposition product thereof. From this point of view, it is also understood as a “composition”. However, since the catalyst component and the like are in a very small amount, they are referred to as “polyester resin” in the present application. In addition, various additives may be included in the polyester resin of the present invention as long as the effects of the present invention are not impaired.

Examples of the dicarboxylic acid used as a copolymerization component when the polyester is a copolymer include isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4- Naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenyl-4,4-dicarboxylic acid, 4,4′-biphenyl ether dicarboxylic acid, 1,2-bis (phenoxy) ethane-p , P'-dicarboxylic acid, anthracene dicarboxylic acid and other aromatic dicarboxylic acids, succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid Acid, tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, 1,3- Clobutane dicarboxylic acid, 1,3-cyclopentane dicarboxylic acid, 1,2-cyclohexane dicarboxylic acid, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, 2,5-norbornane dicarboxylic acid, dimer acid, water An unsaturated dicarboxylic acid such as an aliphatic dicarboxylic acid, an alicyclic dicarboxylic acid, fumaric acid or itaconic acid exemplified as an additive dimer acid can be used.
These dicarboxylic acids are preferably from 0 to 15 mol%, more preferably from 0.5 to 10 mol%, still more preferably from 0.8 to 7.5 mol%, particularly preferably from 0. It can be used in the range of 9 to 5.0 mol%, most preferably 1.0 to 2.5 mol%.

Examples of the glycol as a copolymer component used when the polyester is a copolymer include propylene glycol, 1,3-propanediol, 1,4-butylene glycol, and 1,2-butylene glycol. 1,3-butylene glycol, 2,3-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediethanol, 3-methyl-1,5-pentanediol, 2-methyl-1,5- Pentanediol, 2-methyl-1,3-propanediol 2-ethyl-1,3-propanediol, neopentyl glycol, 2-ethyl-2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-n -Butyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, 2-ethyl-2- n-hexyl-1,3-propanediol, 2,2-di-n-hexyl-1,3-propanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, diethylene glycol , Aliphatic group such as triethylene glycol, polyethylene glycol, polytrimethylene glycol, polytetramethylene glycol, polypropylene glycol Coal, hydroquinone, 4,4′-dihydroxybisphenol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-bis (β-hydroxyethoxyphenyl) sulfone, bis (p-hydroxyphenyl) ether, bis ( Examples include aromatic glycols such as p-hydroxyphenyl) sulfone, bis (p-hydroxyphenyl) methane, 1,2-bis (p-hydroxyphenyl) ethane, bisphenol A, and alkylene oxide adducts of bisphenol A.
These glycols are preferably from 0 to 15 mol%, more preferably from 0.5 to 10 mol%, still more preferably from 0.8 to 7.5 mol%, particularly preferably from 0.9 to 0.1 mol% of all glycol components. It can be used in the range of 5.0 mol%, most preferably 1.0 to 2.5 mol%.

  The intrinsic viscosity of the polyester resin is preferably 0.35 to 1.30 dl / g, more preferably 0.40 to 1.00 dl / g, still more preferably 0.45 to 0.90 dl / g, and particularly preferably 0. .50 to 0.85 dl / g, most preferably 0.55 to 0.80 dl / g. That is, if the intrinsic viscosity is lower than this range, the mechanical strength and impact resistance of the container are insufficient, whereas if it is higher than the above range, injection molding into a bottomed preform tends to be difficult. is there.

2. Catalyst of Polyester Resin As the aluminum compound constituting the polyester polymerization catalyst according to the present invention, a known aluminum compound can be used without limitation.

  Specific examples of the aluminum compound include aluminum acetate, basic aluminum acetate, aluminum lactate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, aluminum acetylacetonate, aluminum oxalate, and other organic aluminum compounds, and these A partial hydrolyzate etc. are mentioned. Among these, carboxylate, inorganic acid salt and chelate compound are preferable, and among these, aluminum acetate, basic aluminum acetate, aluminum lactate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride and aluminum acetylacetonate are more preferable, Aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide and aluminum hydroxide chloride are more preferred, and aluminum acetate and basic aluminum acetate are most preferred.

The amount of the aluminum compound used as the aluminum atom used in the polyester polymerization catalyst according to the present invention is preferably 1 to 60 ppm, more preferably 2 to 50 ppm, based on the total mass of the polyester resin obtained. Yes, more preferably 3 to 40 ppm, particularly preferably 5 to 30 ppm, and most preferably 10 to 20 ppm.
If it is less than the above, the catalyst activity may be poor, and if it exceeds the above, the generation of foreign substances derived from the aluminum compound may be caused, leading to a decrease in Tc1 and an increase in Tc2.

  The phosphorus compound constituting the polyester polymerization catalyst is a phosphorus compound having a hindered phenol structure as represented by the following chemical formula (formula A).

In (Formula A), X1 and X2 each represent hydrogen, an alkyl group having 1 to 4 carbon atoms, or a monovalent or higher metal.
Further, X1 may be a metal having a valence of 2 or more, and X2 may not be present. Furthermore, an anion corresponding to the surplus valence of the metal may be arranged with respect to the phosphorus compound.
As the metal, Li, Na, K, Ca, Mg, and Al are preferable.

  Specific examples of the compound represented by the chemical formula (formula A) include phosphorus compounds represented by the chemical formulas (Chemical Formula 1) and (Chemical Formula 2).

  Irgamod 295 (manufactured by BASF) is commercially available as the compound represented by the above chemical formula (Chemical Formula 1), and Irgamod 195 (manufactured by BASF) is commercially available as the compound represented by (Chemical Formula 2). It can be used.

The amount of the phosphorus compound used is preferably 20 to 65 ppm, more preferably 25 to 60 ppm, and still more preferably 30 to 55 ppm as phosphorus atoms with respect to the total mass of the resulting polyester resin. Especially preferably, it is 35-52 ppm, Most preferably, it is 40-50 ppm.
However, when the phosphorus compound is placed in a reduced pressure environment at the time of polyester polymerization, about 10 to 30% of the addition amount is removed from the system depending on the conditions. Therefore, in practice, it is necessary to determine the amount of addition after conducting trial experiments several times under different conditions and determining the residual ratio of the phosphorus compound in the polyester.
When the amount of the phosphorus compound added is small, the catalyst activity may be poor, or foreign matter generation derived from the aluminum compound may be caused. Even if the amount is too large, the catalyst activity as a polyester polycondensation catalyst may be reduced. The tendency of the reduction varies depending on the amount of aluminum compound added. When the catalytic activity is poor, as will be described later, a large amount of temperature time product in the polycondensation is required, so that the amount of decomposition of the phosphorus compound increases and it becomes difficult to set Tc1 to 170 ° C. or higher. There is.
Moreover, when there is too much addition amount of a phosphorus compound, although mentioned later, the amount of decomposition products of a phosphorus compound increases and it may become difficult to make Tc1 170 degreeC or more.

The ratio P / Al (molar ratio) of the phosphorus compound represented by the chemical formula (formula A) contained in the polyester resin and the phosphorus atom of the total phosphorus compound including the thermal decomposition product thereof and the aluminum atom of the aluminum compound is: It is preferable that 1.4 ≦ P / Al ≦ 100, more preferably 1.5 ≦ P / Al ≦ 50, still more preferably 1.6 ≦ P / Al ≦ 20, and particularly preferably 1. 7 ≦ P / Al ≦ 10, and most preferably 1.8 ≦ P / Al ≦ 5.
If P / Al is too low, the catalytic activity as a polyester polycondensation catalyst may decrease or foreign matter generation derived from an aluminum compound may occur, resulting in a decrease in Tc1 and an increase in Tc2. The catalytic activity as a catalyst may decrease. When the catalytic activity decreases, it may be difficult to set Tc1 to 170 ° C. or higher. When a large amount of foreign matter derived from the aluminum compound is generated, it becomes difficult to set Tc2 to 175 ° C. or lower.

In the polycondensation catalyst according to the present invention, other polycondensation catalysts such as an antimony compound, a germanium compound, and a titanium compound may coexist within a range of addition amounts that do not cause problems in the product such as polyester characteristics, processability, and color tone. Although it is good, it is preferable that these are not substantially contained.
When coexisting, the antimony compound is preferably in an amount of 30 ppm or less as antimony atoms with respect to the polyester obtained by polycondensation. More preferably, it is 20 ppm or less, More preferably, it is 10 ppm or less, Most preferably, it is 5 ppm or less. If the addition amount of antimony exceeds 30 ppm, metal antimony is precipitated, and Tc1 and Tc2 may be out of the above ranges, which is not preferable.

  In the case of coexistence, the germanium compound is preferably in an amount of 10 ppm or less as germanium atoms with respect to the polyester obtained by polycondensation. More preferably, it is 5 ppm or less, More preferably, it is 3 ppm or less, Most preferably, it is 2 ppm or less. If the amount of germanium added exceeds 10 ppm, it is not preferable because it is disadvantageous in terms of cost.

  When coexisting, it is preferable that a titanium compound is 3 ppm or less as a titanium atom with respect to polyester obtained by polycondensation. More preferably, it is 2 ppm or less, More preferably, it is 1 ppm or less. If the amount of titanium added is more than 3 ppm, the resulting polyester will be markedly colored, and the thermal stability will be significantly reduced.

  When coexisting, the sodium compound is preferably in an amount of 20 ppm or less as a sodium atom with respect to the polyester obtained by polycondensation. More preferably, it is 10 ppm or less, More preferably, it is 5 ppm or less, Most preferably, it is 2 ppm or less. If the amount of sodium added exceeds 20 ppm, the haze at the time of molding the resulting polyester deteriorates and the hydrolysis resistance decreases, which is not preferable.

  When coexisting, the magnesium compound is preferably in an amount of 100 ppm or less as a magnesium atom with respect to the polyester obtained by polycondensation. More preferably, it is 50 ppm or less, More preferably, it is 20 ppm or less, Most preferably, it is 10 ppm or less. If the amount of magnesium added exceeds 100 ppm, the thermal oxidation stability of the resulting polyester deteriorates, which is not preferable.

  When coexisting, the lithium compound is preferably in an amount of 50 ppm or less as lithium atoms with respect to the polyester obtained by polycondensation. More preferably, it is 20 ppm or less, More preferably, it is 10 ppm or less, Most preferably, it is 5 ppm or less. If the amount of lithium added exceeds 50 ppm, it is not as good as a sodium compound, but the haze at the time of molding the resulting polyester deteriorates and the hydrolysis resistance decreases, which is not preferable.

3. Preparation of catalyst When an aluminum compound and a phosphorus compound are used as a catalyst, it is preferably added in the form of a slurry or a solution, and is preferably solubilized in a solvent such as water or glycol, particularly water and / or ethylene glycol. It is preferable to use a solubilized one.

The method for dissolving the aluminum compound is exemplified below.
(1) Preparation Example of Basic Aluminum Acetate Aqueous Solution Water is added to basic aluminum acetate and stirred at 50 ° C. or lower for 3 hours or longer. The stirring time is more preferably 6 hours or longer. Thereafter, stirring is performed at 60 ° C. or more for several hours or more. The temperature in this case is preferably in the range of 60 to 100 ° C. The stirring time is preferably 1 hour or longer. The concentration of the aqueous solution is preferably 10 g / l to 30 g / l, particularly preferably 15 g / l to 20 g / l.

(2) Preparation Example of Ethylene Glycol Solution of Basic Aluminum Acetate Ethylene glycol is added to the above aqueous solution. The amount of ethylene glycol added is preferably 0.5 to 5 times the volume ratio of the aqueous solution. More preferably, the amount is 1 to 3 times. The solution is stirred at room temperature for several hours to obtain a uniform water / ethylene glycol mixed solution. Thereafter, the solution is heated and water is distilled off to obtain an ethylene glycol solution. The temperature is preferably 80 ° C. or higher, and preferably 200 ° C. or lower. More preferably, the water is distilled off by stirring at 90 to 150 ° C. for several hours. The system may be depressurized during distillation. By reducing the pressure, ethylene glycol can be rapidly distilled off at a lower temperature. That is, under reduced pressure, distillation can be performed even at 80 ° C. or lower, and the heat history applied to the system can be further reduced.

(3) Preparation example of aluminum glycol solution of aluminum lactate An aqueous solution of aluminum lactate is prepared. The preparation may be performed at room temperature or under heating, but room temperature is preferred. The concentration of the aqueous solution is preferably 20 g / l to 100 g / l, particularly preferably 50 to 80 g / l. Ethylene glycol is added to the aqueous solution. The amount of ethylene glycol added is preferably 1 to 5 times the volume ratio of the aqueous solution. More preferably, the amount is 2-3 times. After stirring this solution at normal temperature and obtaining a uniform water / ethylene glycol mixed solution, this solution is heated and water is distilled off to obtain an ethylene glycol solution. The temperature is preferably 80 ° C. or higher, and preferably 120 ° C. or lower. More preferably, the water is distilled off by stirring at 90 to 110 ° C. for several hours.

It is preferable to heat-treat after dissolving the phosphorus compound. By this treatment, the polycondensation catalyst activity is improved, the foreign matter formation property due to the polycondensation catalyst is lowered, and Tc2 can be lowered. The solvent used for the heat treatment is not limited as long as it is at least one selected from the group consisting of water and alkylene glycol, but it is preferable to use a solvent that dissolves the phosphorus compound.
As the alkylene glycol, it is preferable to use glycol which is a constituent component of the target polyester such as ethylene glycol.
The heat treatment in the solvent is preferably performed after dissolving the phosphorus compound, but may not be completely dissolved.
Further, it is not necessary for the compound to retain the original structure after the heat treatment, and it is more preferable to improve the polymerization activity to modify the structure so that the solubility in a solvent is improved.

  The temperature of the heat treatment is not particularly limited, but is preferably in the range of 150 to 200 ° C, more preferably in the range of 155 to 195 ° C, still more preferably in the range of 160 to 190 ° C, and particularly preferably. Is in the range of 165-185 ° C, most preferably in the range of 170-180 ° C.

  The heating time varies depending on conditions such as temperature, and is preferably 3 to 7 hours at 160 ° C and 0.2 to 0.5 hours at 200 ° C. If the heating time is too short, the polymerization activity may decrease. If the catalytic activity is insufficient, it may be difficult to set Tc1 to 170 ° C. or higher. On the other hand, if the heating time is too long, the amount of pyrolyzate of the phosphorus compound increases, and the temperature rise crystallization temperature (Tc1) may decrease.

  The temperature at the time of storing the solution obtained by heat-treating the phosphorus compound is preferably a low temperature of 100 ° C. or less. When the temperature is high, the amount of pyrolyzate of the phosphorus compound increases in a short time, and the temperature rise crystallization temperature (Tc1) may decrease.

4). Polyester polymerization method There are no particular restrictions on the polyester production method, and direct esterification of polyhydric carboxylic acid containing terephthalic acid with polyhydric alcohol or transesterification of alkyl ester such as terephthalic acid with polyhydric alcohol An oligomer of terephthalic acid or the like and a polyhydric alcohol can be obtained by the method, and then polyester can be obtained by melt polycondensation under normal pressure or reduced pressure. At this time, an esterification catalyst or the above-mentioned polycondensation catalyst can be used as necessary.

The production of the polyester according to the present invention is a method comprising a conventionally known process except that a polyester polymerization catalyst comprising an aluminum compound and a phosphorus compound is used as a catalyst, and the following catalyst addition method and polycondensation conditions are noted. It can be carried out. For example, in the case of producing PET, a direct esterification method in which terephthalic acid, ethylene glycol, and if necessary, other copolymerization components are directly reacted, water is distilled off and esterification is performed, and then polycondensation is performed under reduced pressure. Alternatively, it is produced by a transesterification method in which dimethyl terephthalate, ethylene glycol, and other copolymerization components as required are reacted to distill off methyl alcohol for transesterification, followed by polycondensation under reduced pressure. Further, solid phase polymerization may be performed as necessary to increase the intrinsic viscosity. In order to promote crystallization before solid phase polymerization, the melt-polymerized polyester may be moisture-absorbed and then heat-crystallized, or steam may be sprayed directly onto the polyester chip to heat-crystallize.
The melt polycondensation reaction is preferably performed in a continuous reaction apparatus. Continuous reaction equipment means that the reaction vessel for esterification or transesterification and the melt polycondensation reaction vessel are connected by piping, and the raw materials are continuously charged without melting each reaction vessel, and the melt polycondensation reaction in the piping This is a method of transferring to a container and extracting the resin from the melt polycondensation reaction container. In this case, continuous does not need to be completely withdrawn from the raw material input, but is intermittent, such as withdrawing from the raw material input in small amounts, for example, about 1/10 of the reaction vessel amount. It may be anything.
In any of these methods, the esterification reaction or transesterification reaction may be performed in one stage or may be performed in multiple stages. The melt polycondensation reaction may be performed in one stage or may be performed in multiple stages. The solid phase polymerization reaction can be carried out in a continuous apparatus as in the melt polycondensation reaction.

By using a continuous reaction apparatus, a polyester having a high Tc1 and a low Tc2 can be stably obtained. However, in the case of a batch type (batch type), it is often difficult to obtain such a polyester. It is considered that the previous batch of polyester remaining in the reactor is subjected to a thermal history, resulting in an increase in the decomposition products of the catalyst or the influence of the decomposition products of the resin itself. In the case of the batch type, other types of resins such as polyesters and polyamides having different compositions are generally produced in the same reaction apparatus, and it is considered that these are affected by the residuals.
In the case of a batch type, it takes several tens of minutes to several hours to withdraw the entire amount of resin from the reactor after completion of polyester polymerization. During this period, decomposition of the phosphorus compound proceeds, resulting in a decrease in Tc1, and within the same lot. Not only may there be a problem that the Tc1 fluctuates, but a decrease in Tc1 may occur when the chips are uniformly mixed as a whole.

Even when a continuous reaction apparatus is used, immediately after the start of production, it may be difficult to obtain a polyester having a high Tc1 and a low Tc2 under the influence of a previously produced resin. . Although it depends on the scale and production volume of the apparatus and the resin produced previously, it is preferable to collect the sample after 24 to 48 hours have elapsed after the start of operation or change of conditions and the quality has been stabilized.
In order to take advantage of the merits of the continuous reaction apparatus, it is preferable to carry out production on a scale of 1 ton or more per hour. The upper limit is about 50 tons per hour. Moreover, it is preferable to produce for 2 days or more under the same conditions.

5. Addition of catalyst In the present invention, it is important to add the aluminum compound solution and the phosphorus compound solution simultaneously. The simultaneous addition includes a method of adding each independently to the same reaction vessel or a pipe between the reaction vessels, and a method of mixing an aluminum compound solution and a phosphorus compound solution in advance to make one solution. Examples of the one-liquid method include a method in which the respective solutions are mixed in a dunk, and a method in which pipes to which a catalyst is added are joined together and mixed.
In addition, when adding to a reaction container, it is preferable to make stirring of a reaction container high. When adding to the piping between the reaction vessels, it is preferable to install an in-line mixer or the like so that the added catalyst solution is promptly and uniformly mixed.

When the aluminum compound solution and the phosphorus compound solution are added separately, a large amount of foreign matter due to the aluminum compound is likely to be generated, and Tc1 may be lowered, Tc2 may be increased, and sufficient catalytic activity may not be obtained. By simultaneously adding the aluminum compound and the phosphorus compound, a complex of the aluminum compound and the phosphorus compound that brings about the polymerization activity can be quickly generated without waste, but when added separately, the complex of the aluminum compound and the phosphorus compound This is considered to be due to the fact that the aluminum compound, which was not sufficiently formed and the complex with the phosphorus compound could not be formed, was deposited as a foreign substance. In particular, it is considered that the aluminum compound precipitated as a foreign substance acts as a crystal nucleating agent, thereby increasing Tc2.
Further, it is important to add the aluminum compound solution and the phosphorus compound solution after the esterification reaction or the transesterification reaction. If added before the end of the esterification reaction or transesterification reaction, Tc1 may be lowered. As will be described later, this is considered to be because the pyrolysis of the phosphorus compound proceeds in the esterification step and the decomposition products increase.

6). Polycondensation In order to obtain a polyester resin having a high Tc1, the conditions of the polycondensation step are important factors.
The present inventors investigated the relationship between the polymerization conditions of polyester using a catalyst composed of an aluminum compound and a phosphorus compound and the crystallization temperature, and examined the cause and the solution. As a result, Tc1 varied depending on the polycondensation temperature and time. I figured out what to do.
Further, it was revealed that the cause of Tc1 fluctuation was a specific decomposition product of a phosphorus compound used as a catalyst, and the production conditions were optimized and the amount of this decomposition product was controlled, thereby making aluminum A polyester resin using a catalyst comprising a compound and a phosphorus compound can be a conventionally known polyester resin having a Tc1 of 170 ° C. or higher and a Tc2 of 175 ° C. or lower. It has been found that when used in a heat-resistant bottle, it is easy to control the crystallization of the plug part, and when used in a molding sheet, it is difficult to whiten during heating in molding.
This will be described below.

The phosphorus compound is decomposed in the polycondensation process.
Although there are various decomposition products of the phosphorus compound, as a result of the study by the present inventors, in particular, the following (B) is one in which one t-Bu group of the phosphorus compound of the above (formula A) is removed. It was found that the structure has a great influence on Tc1.

(B) It is preferable that the phosphorus compound shown by a structure is 5-11 ppm in a polyester resin. The lower limit of the phosphorus pyrolyzate is preferably 5.5 ppm, more preferably 6 ppm, particularly preferably 6.5 ppm, and most preferably 7 ppm.
The upper limit of the amount of pyrolyzate is preferably 10.5 ppm, more preferably 10 ppm, particularly preferably 9.5 ppm, and most preferably 9 ppm.
In addition, although the thing of (B) structure is considered to exist as Al salt in resin, in a measurement, it will become "-PO (OH) ₂ " by adding phosphoric acid, (B) The amount of the phosphorus compound represented by the structure is a value assuming that the “—P—O—” portion becomes “—P—OH”.
In the production of (B) by decomposition, the higher the polycondensation temperature and the longer the time, the more the decomposition proceeds. Therefore, it is preferable to set the temperature and time within a specific range.
That is, the temperature-time product represented by [polycondensation temperature−240] (° C.) × polycondensation time (min) is preferably 1000 to 6500 (° C. × min), more preferably 2000 to 6300 (° C. × min). More preferably, it is 2500 to 6200 (° C. × min), particularly preferably 3000 to 6100 (° C. × min), and most preferably 3500 to 6000 (° C. × min).
When the above range is exceeded, it may be difficult to set Tc1 to 170 ° C. or higher. Moreover, if it is below the above range, realistic melt polycondensation is difficult.
Here, the reason why the temperature is 240 ° C. or higher is that the temperature at which a significant difference is recognized as the polycondensation time is 5 to 10 minutes and the temperature at which a significant difference is also caused in the decomposition of the phosphorus compound is 240 ° C. or higher.

  In addition, the temperature time product here is the product of the average residence time in each polycondensation can and the temperature in the can, and when using a plurality of polycondensation cans, the temperature time product is calculated in each reaction can, It is the total. If there is a temperature gradient near the entrance to the exit in the can, the average temperature is taken.

  First, since the fluctuation of Tc1 tends to become more stable by lowering the temperature, the polycondensation temperature is preferably 250 to 285 ° C, more preferably 255 to 283 ° C, still more preferably 260 to 260 ° C. It is 282 degreeC, Most preferably, it is 265-281 degreeC, Most preferably, it is 270-280 degreeC. When the temperature exceeds 285 ° C., the decomposition proceeds rapidly, and it becomes difficult to stably adjust the amount of decomposition product in the polycondensation time. When the temperature is less than 250 ° C., the polycondensation time becomes too long, and economical production becomes difficult.

  The polycondensation time is preferably 50 to 350 minutes, more preferably 90 to 310 minutes, still more preferably 120 to 280 minutes, particularly preferably 140 to 260 minutes, and most preferably 150 to 250 minutes. is there. In order to make it less than 50 minutes, it is necessary to raise the temperature, and a slight time fluctuation affects the amount of decomposed products, making it difficult to produce a stable polyester resin with Tc1. Economic production becomes difficult in 350 minutes or more.

  In addition, the decomposition of the phosphorus compound proceeds even during heat treatment and storage of the solution of the phosphorus compound. Those that received a history of more than the above-mentioned temperature and time during heat treatment, and those that received a relatively high temperature / long-term thermal history during storage have a large amount of decomposition products of phosphorus compounds, and the temperature time under polycondensation conditions It is preferable to make the product smaller.

  Furthermore, naturally the amount of decomposition products is influenced by the amount of the phosphorus compound used as a catalyst. When a large amount of phosphorus compound is used, it is preferable to reduce the temperature time product.

In the case of continuous polycondensation, the temperature can be set by setting the reactor, and the time can be adjusted by the amount of raw material input. Furthermore, the polycondensation can be carried out at the target temperature and time product by adjusting the rate of polycondensation by adjusting the degree of pressure reduction and stirring in the reaction vessel.
Further, in order to obtain a melt polymerization resin having a high IV, it is generally necessary to increase the temperature-time product, and it may be difficult to achieve the above preferred range. In such a case, the polycondensation can be carried out at a target temperature-time product by increasing the pressure reduction degree in the reaction vessel and increasing the stirring to increase the speed of polycondensation.

7). Others The polyester resin of the present invention is formed into a hollow molded body, a film, a sheet-like material, a fiber, other molded bodies, etc. by using a generally used melt molding method, and another base material by a melt extrusion method. An overcoated coating can be formed.
The mechanical strength can be improved by stretching a sheet-like material made of the polyester resin of the present invention at least in a uniaxial direction.
The stretched film made of the polyester resin of the present invention is a sheet-like material obtained by injection molding or extrusion molding, and can be any one of uniaxial stretching, sequential biaxial stretching, and simultaneous biaxial stretching that are usually used for PET stretching. It is molded using a stretching method. Further, it can be formed into a cup shape or a tray shape by pressure forming or vacuum forming.

  Especially, it is used suitably for a hollow molded object. Especially, it is used suitably as a bottle for drinks which crystallized the stopper part and improved heat resistance. In this case, the polyester includes at least one resin selected from the group consisting of polyolefin resin, polyamide resin, polyacetal resin, and polybutylene terephthalate resin in order to improve crystallization characteristics. It is also preferable to blend 1000 ppm, preferably 0.3 ppb to 100 ppm, more preferably 0.5 ppb to 1 ppm, and still more preferably 0.5 ppb to 45 pbb.

  The method of blending the above resin with the polyester resin is preferably a method that can be uniformly mixed, such as addition in the polyester production process, dry blending with the polyester after production, etc. In the polyester production process, specifically, the raw material The slurry is preferably added at any time during the preparation of the slurry, at any stage of the esterification reaction or transesterification reaction, and at the beginning of the polycondensation reaction step. A method in which a PET chip is brought into contact with the crystalline resin member is also a preferable mode.

  When such a crystalline resin is added to the polyester resin of the present invention, a stable Tc1 resin can be obtained. In particular, the effect is remarkable when blended with polyester after production. This is because when the original polyester resin has a Tc1 of 170 ° C. or lower, a very small amount of crystalline resin is added when trying to set the Tc1 of 160 to 165 ° C., which is most preferable for crystallization of the plug portion. This is considered to be because the added amount tends to vary.

The polyester resin of the present invention is, for example, a method in which molten polyester is extruded into water from the die pores after the end of melt polycondensation and cut in water, or after extrusion into the air from the die pores in the air after the end of melt polycondensation. Then, it is made into chips by a method of making chips while cooling with cooling water. The shape of the chip may be any of a cylinder shape, a square shape, a spherical shape, a flat plate shape, and the like, but a flat shape is particularly preferable. For example, in the case of a cylinder type, it is practical that the length is 1.0 to 4 mm, the major axis and the minor axis are about 1.0 to 4 mm. In the case of spherical particles, it is practical that the diameter is 1 to 4 mm.
The weight per chip is preferably 10 to 50 mg, more preferably 20 to 45 mg, and particularly preferably 25 to 40 mg.

  Such chips are supplied in units of 10 kg or more. Examples of containers include paper bags, metal and paper drums, flexible container (flexible) bags, and dedicated tanks. In the case of a paper bag, 15-35 kg is contained. In the case of a drum can, 30-100 kg is contained in a small drum, 150-300 kg is contained in a large drum, 0.5-2 tons is contained in a flexible container bag, and 2-30 in the case of a dedicated tank. In general, a ton tank truck is used. Among these, a flexible container bag and a dedicated tank are preferable.

  Further, the chips are preferably supplied in a dry state. The moisture content of the chip is preferably 3000 ppm or less, more preferably 1000 ppm or less, and particularly preferably 100 ppm or less.

  As a continuous drying method, a hopper type ventilation dryer is generally used in which a polyester chip is supplied from the upper part and a drying gas is supplied from the lower part. As a dryer for drying in a batch mode, drying may be performed while aeration gas is passed under atmospheric pressure. In this case, it may be carried out while standing with a hopper-shaped dryer, or may be carried out with a rotary blender.

  As the dry gas, atmospheric air may be used, but dry nitrogen and dehumidified air are preferable from the viewpoint of preventing molecular weight reduction due to hydrolysis or thermal oxidative decomposition of polyester. The drying temperature is about 50 ° C. to about 150 ° C., preferably about 60 ° C. to about 140 ° C., and the drying time is 3 hours to 15 hours, preferably 4 hours to 10 hours. After drying, it is once stored in a hopper and then put into a container to become a product. In addition, since the chip | tip after solid-phase polymerization is a dry state, further drying is not required. It is stored in the hopper as it is in a dry state.

  The polyester resin of the present invention is suitably used as a hollow molded article for beverages. In particular, it is suitably used for a heat-resistant bottle that has been crystallized by heating the stopper portion.

  In addition, a molding sheet is one of preferable applications. This sheet is formed into a recup shape or a tray shape by pressure forming or vacuum forming, but can be heated at a high temperature at the time of forming, and can be easily formed into a molded product having a complicated structure.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The main characteristic value measurement methods will be described below.

(1) Intrinsic viscosity of polyester resin (IV)
It calculated from the solution viscosity at 30 degreeC in a 1,1,2,2-tetrachloroethane / phenol (2/3 weight ratio) mixed solvent.

(2) Crystallization temperature of polyester resin (Tc1 / Tc2)
The measurement was performed using a differential thermal analyzer (DSC) TAS100 thermal analysis system manufactured by TA Instruments. The polyester resin 7.5 ± 0.3 mg was put in an aluminum pan, heated to 280 ° C. using a melting point measuring device, held for 1 minute, and then rapidly cooled with liquid nitrogen. The sample was heated from room temperature to 300 ° C. at a temperature rising rate of 20 ° C./min, and the temperature rising crystallization temperature (Tc1) and the melting point (Tm) were measured. Further, after reaching 300 ° C., it was held for 2 minutes, and then cooled at a rate of temperature decrease of 10 ° C./min, and the crystallization temperature (Tc2) during temperature decrease was measured. Tc1, Tc2, and Tm were the temperatures of the maximum portions of the respective peaks.
In addition, about 30-40 mg of polyester chips were finely chopped with a nipper, and samples were selected from these pieces so as to have a prescribed weight either alone or in combination. Furthermore, another sample was selected from the fragments obtained from the same five chips, and the measurement was performed for a total of five measurements. The average value of the values obtained by the five measurements was taken as the values of Tc1, Tc2, and Tm.

(3) Aluminum determination method (dry decomposition method)
The polyester resin was weighed in a platinum crucible, and carbonized on an electric stove, and then incinerated in a muffle furnace at 550 ° C./8 hours. The sample after ashing was acid-treated with 6M hydrochloric acid and then made up to 20 ml with 1.2M hydrochloric acid.
The metal concentration was determined by ICP luminescence measurement.
Apparatus: CIROS-120 manufactured by SPECTRO
Plasma output: 1400W
Plasma gas: 13.0L / min
Auxiliary gas: 2.0 L / min
Nebulizer: Cross flow nebulizer Chamber: Cyclone chamber Measurement wavelength: 167.078 nm

(4) Phosphorus determination method (molybdenum blue colorimetric method)
1. Wet decomposition with sulfuric acid, nitric acid and perchloric acid was performed.
After the operation of 2.1, the solution was neutralized with ammonia water.
To the solution prepared in 3.2, ammonium molybdate and hydrazine sulfate were added.
4). The absorbance at a wavelength of 830 nm was measured using an ultraviolet-visible absorptiometer UV-1700 manufactured by Shimadzu Corporation.

(5) Hollow container continuous molding evaluation method Sample polyester was dried in a vacuum dryer to a moisture content of 100 ppm or less, 150C-DM type injection molding machine manufactured by Meiki Seisakusho, and mold for preform (mold temperature) (5 ° C.) was used to form a bottomed preform (PF). As plasticizing conditions by the M-150C-DM injection molding machine, the feed screw rotation speed is 70%, the screw rotation speed is 120 rpm, the back pressure is 0.5 MPa, the cylinder temperature is 45 ° C., 250 ° C. and the nozzle in order from directly below the hopper. The cylinder temperature after the inclusion (hereinafter referred to as Sx) was set to 290 ° C. Further, the injection pressure and the holding pressure were adjusted so that the weight of the molded product was 28.4 ± 0.2 g.
Next, the plug portion of the preform was heated and crystallized using an NC-01 plug portion crystallization apparatus manufactured by Frontier Corporation. Furthermore, using a SBO LabN ° 1045 type 1Lab blow molding machine manufactured by Sidel, a vertical method at 750 bp in a molding cycle of 30 seconds while blowing air at a pressure of 36 bar in a mold set at 160 ° C. The preform was blown biaxially at a magnification of 2.5 times in the circumferential direction and 3.8 times in the circumferential direction.

(6) Haze (degree of brightness:%)
As shown in FIG. 1 and FIG. 2, the polyester which has been vacuum-dried at 140 ° C. for about 16 hours using a vacuum dryer DP61 type manufactured by Yamato Scientific Co., Ltd. is injected into an injection molding machine M-150C-DM type injection molding machine manufactured by Meiki Seisakusho. 2 mm to 11 mm having a gate part (G) (A part thickness = 2 mm, B part thickness = 3 mm, C part thickness = 4 mm, D part thickness = 5 mm, E part thickness = 10 mm, F part A stepped molded plate having a thickness of (thickness = 11 mm) was injection molded.
In order to prevent moisture absorption during molding, the inside of the molding material hopper was purged with a dry inert gas (nitrogen gas). The plasticizing conditions of the M-150C-DM injection molding machine are: feed screw rotation speed = 70%, screw rotation speed = 120 rpm, back pressure 0.5 MPa, cylinder temperature 45 ° C., 250 ° C. from the bottom of the hopper in order, nozzle The temperature was set at 290 ° C. The injection conditions are 20% for injection speed and holding pressure, and the injection pressure and holding pressure are adjusted so that the weight of the molded product is 146 ± 0.2 g. In this case, the holding pressure is 0.5 MPa relative to the injection pressure. Adjusted low.
The upper limit of the injection time and pressure holding time was set to 10 seconds and 7 seconds, respectively, and the cooling time was set to 50 seconds, and the total cycle time including the time for taking out the molded product was about 75 seconds.
Although the temperature of the mold was constantly controlled by introducing cooling water having a water temperature of 10 ° C., the mold surface temperature at the time of molding stability was around 22 ° C.
The test plate for evaluating the molded product characteristics was arbitrarily selected from the 11th to 18th shots of the stable molded product after the molding material was introduced and the resin was replaced.
A 5 mm thick plate (D section in FIG. 1) was used for haze measurement.
The haze of the sample was measured using a Nippon Denshoku Co., Ltd. haze meter model NDH2000.

(7) Quantification method of pyrolyzate amount (phosphorus compound with (B) structure) 420 mg of sample polyester was dissolved in 2.7 ml of HFIP + C ₆ D ₆ (1 + 1) mixed solvent, and 10 μl of 25% heavy acetone solution of phosphoric acid was added. Centrifugation was performed. 105-125 mg of trifluoroacetic acid was added to the supernatant, and P-NMR measurement was immediately performed. In the obtained spectrum, the ratio of the integral value at 32.3, which is the chemical shift value corresponding to the thermal decomposition product of the corresponding phosphorus compound, to the total sum of the integral values corresponding to the other phosphorus compounds is obtained, The molar ratio of the corresponding thermal decomposition product to the total phosphorus compounds was used. From this value and the value of the phosphorus compound amount in (4), the amount of pyrolyzate of the corresponding phosphorus compound in the polyester was calculated.

(8) Moisture content of polyester chip A Karl Fischer trace moisture measuring device CA-100 type and a moisture vaporizer VA-100 manufactured by Mitsubishi Chemical Corporation were used. A moisture vaporizer VA-100 manufactured by Mitsubishi Chemical was previously dried in two drying cylinders (filled with silica gel and phosphorus pentoxide), and the heating furnace was heated to 230 ° C. while flowing nitrogen gas at a flow rate of 250 ml / min. The sample board was put into a heating furnace, and after confirming that the dry nitrogen obtained from the heating furnace and the sample board was anhydrous with a trace moisture measuring device CA-100, the sample 3g was dried. The sample container was precisely weighed, and the sample was quickly placed on the sample board. The water vaporized from the sample was transported to a trace moisture measuring device CA-100 by dry nitrogen and subjected to Karl Fischer titration to determine the moisture content.

(9) Average weight of polyester chip Randomly 100 chips were taken (excluding the case where two or more chips were fused), and their weights were measured to determine the weight per grain.

Example 1
(1) Preparation of aluminum compound After adding an equal amount (volume ratio) of ethylene glycol to a 20 g / l aqueous solution of basic aluminum acetate (hydroxyaluminum diacetate) in a preparation tank and stirring at room temperature for several hours, While stirring at 50 to 90 ° C. for several hours under reduced pressure (3 kPa), water was distilled off from the system to prepare an ethylene glycol solution of 20 g / l aluminum compound.

(2) Preparation Example of Phosphorus Compound As a phosphorus compound, Irgamod 295 (manufactured by BASF) represented by the above (Chemical Formula 1) was charged into a preparation tank together with ethylene glycol, and the liquid temperature was 175 ° C. while stirring under nitrogen substitution. The mixture was heated for half an hour to prepare an ethylene glycol solution of a phosphorus compound at 50 g / l.

(3) Esterification reaction and polycondensation A high-speed stirrer is provided on the transfer line from the third esterification reactor to the first polycondensation reactor, comprising three continuous esterification reactors and three polycondensation reactors. A slurry prepared by mixing 0.75 parts by mass of ethylene glycol with respect to 1 part by mass of high-purity terephthalic acid is continuously supplied to a continuous polyester production apparatus in which an in-line mixer having a first is installed. Reaction was performed at a reaction temperature of 255 ° C. and 170 kPa in the esterification reactor, a reaction temperature of 261 ° C. in the second esterification reactor, and a reaction temperature of 266-267 ° C. in the third esterification reactor to obtain a low-order condensate. .
The low-order condensation product is continuously transferred to a continuous polycondensation apparatus consisting of three reactors, the reaction temperature of the initial polymerization reactor is 268 ° C., the reaction temperature of the medium-term polymerization reactor is 270 ° C., 0.567 kPa, Polycondensation was carried out at a reaction temperature of 274 ° C. and 0.168 kPa in the late polymerization reactor to obtain PET having an IV of 0.554 dl / g. The polycondensation time at this time was 190 minutes in total, and the temperature time product was 5640 ° C. · min. The polyester resin was extruded into a strand shape, cooled in water, cut, and after removing water droplets with a vibrating sieve, it was put into a continuous hopper dryer and dried with 140 ° C. dry nitrogen gas for 12 hours. The chips taken out continuously were once stored in a hopper and then put into a 1000 kg flexible container bag to obtain a product form.
In addition, in order to eliminate the influence of the previous batch and secure a high-quality product, the product was collected after 30 hours or more after the start of operation or after the change of conditions.
From the in-line mixer, the ethylene compound solution of the aluminum compound prepared by the above-described method is adjusted so that the residual amount after the polycondensation is 15 ppm as aluminum atoms with respect to the mass of the obtained polyester resin. The ethylene glycol solution was added so that the residual amount after completion of polycondensation was 45 ppm as phosphorus atoms with respect to the mass of the obtained polyester resin.
The cut surface of the chip was a saddle shape with a minor axis of 2.5 mm and a major axis of 3.0 mm, a length of 3.3 mm (both average values measured with 10 calipers), and an average weight of 36.2 mg. The water content was 50 ppm.
The evaluation results of the PET thus obtained are shown in Table 1.

(Comparative Example 1)
The reaction was conducted in the same manner as in Example 1 except that the reaction temperature of the initial polymerization reactor was 275 ° C., the reaction temperature of the intermediate polymerization reactor was 278 ° C. and 1.394 kPa, and the reaction temperature of the late polymerization reactor was 282 ° C. and 0.234 kPa. 544 dl / g of PET was obtained. The polycondensation time at this time was 190 minutes in total, and the temperature time product was 7050 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

(Comparative Example 2)
The reaction was carried out in the same manner as in Example 1 except that the reaction temperature of the initial polymerization reactor was 276 ° C., the reaction temperature of the intermediate polymerization reactor was 282 ° C. and 1.589 kPa, and the reaction temperature of the late polymerization reactor was 284 ° C. and 0.3 kPa. Obtained .563 dl / g PET. The polycondensation time at this time was 190 minutes in total, and the temperature-time product was 7400 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

(Example 2)
The reaction was conducted in the same manner as in Example 1 except that the reaction temperature of the initial polymerization reactor was 269 ° C., the reaction temperature of the intermediate polymerization reactor was 272 ° C. and 0.450 kPa, and the reaction temperature of the late polymerization reactor was 275 ° C. and 0.115 kPa. Obtained .578 dl / g PET. The polycondensation time at this time was 190 minutes in total, and the temperature time product was 5870 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

(Example 3)
Except that the number of rotations of the in-line mixer was set higher, the same operation as in Example 1 was carried out to obtain PET with an IV of 0.578 dl / g. The polycondensation time at this time was 190 minutes in total, and the temperature time product was 5640 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

Example 4
As in Example 3, except that three continuous esterification reactors and two polycondensation reactors were used, the reaction temperature of the initial polymerization reactor was 270 ° C., and the reaction temperature of the late polymerization reactor was 275 ° C. This gave PET with an IV of 0.565 dl / g. The polycondensation time at this time was 130 minutes in total, and the temperature time product was 4100 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

(Example 5)
The reaction was conducted in the same manner as in Example 3 except that the reaction temperature of the initial polymerization reactor was 269 ° C., the reaction temperature of the intermediate polymerization reactor was 275 ° C. and 0.567 kPa, and the reaction temperature of the late polymerization reactor was 280 ° C. and 0.168 kPa. 558 dl / g of PET was obtained. The polycondensation time at this time was 190 minutes in total, and the temperature time product was 6190 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

(Example 6)
An ethylene glycol solution of a phosphorus compound was carried out in the same manner as in Example 1 except that the residual amount after polycondensation was 55 ppm as a phosphorus atom with respect to the mass of the obtained polyester resin. 0.563 dl / g PET was obtained. The polycondensation time at this time was 190 minutes in total, and the temperature time product was 5640 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

(Example 7)
As in Example 6, except that three continuous esterification reactors and two polycondensation reactors were used, the reaction temperature of the initial polymerization reactor was 270 ° C., and the reaction temperature of the late polymerization reactor was 275 ° C. This gave PET with an IV of 0.568 dl / g. The polycondensation time at this time was 130 minutes in total, and the temperature time product was 4100 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

(Example 8)
Except that the degree of vacuum during polycondensation and the rotational speed of the in-line mixer were set higher, PET was performed in the same manner as in Example 3 to obtain PET with an IV of 0.620 dl / g. The polycondensation time at this time was 190 minutes in total, and the temperature time product was 5640 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

Example 9
The PET obtained in Example 3 was subjected to solid phase polycondensation by a conventional method to obtain PET having an IV of 0.720 dl / g. The polycondensation time at this time was 190 minutes in total, and the temperature time product was 5640 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

(Example 10)
Except that the acid component was mixed with 98.5 parts by mass of high-purity terephthalic acid and 1.5 parts by mass of isophthalic acid, the same procedure as in Example 1 was carried out to obtain PET having an IV of 0.556 dl / g. The polycondensation time at this time was 190 minutes in total, and the temperature time product was 5640 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

(Example 11)
An ethylene glycol solution of a phosphorus compound was carried out in the same manner as in Example 1 except that the residual amount after completion of polycondensation was 30 ppm as a phosphorus atom with respect to the mass of the obtained polyester resin. 0.551 dl / g PET was obtained. The polycondensation time at this time was 190 minutes in total, and the temperature time product was 5640 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

(Comparative Example 3)
Except that an ethylene glycol solution of an aluminum compound was added to the second esterification reactor, it was carried out in the same manner as in Example 1 to obtain PET having an IV of 0.552 dl / g. The polycondensation time at this time was 190 minutes in total, and the temperature time product was 5640 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

(Comparative Example 4)
Except that the polycondensation time was 240 minutes, it was carried out in the same manner as in Example 1 to obtain PET having an IV of 0.557 dl / g. At this time, the pressure of the middle-stage polymerization reactor was 0.7 kPa, the pressure of the latter-stage polymerization reactor was 0.23 kPa, and the temperature-time product was 7120 ° C./min.
The evaluation results of the PET thus obtained are shown in Table 1.
(Comparative Example 5)
An ethylene glycol solution of an aluminum compound is added so that the residual amount after completion of polycondensation is 10 ppm as aluminum atoms with respect to the mass of the resulting polyester resin, and an ethylene glycol solution of a phosphorus compound is added after completion of polycondensation In the same manner as in Example 1 except that the residual amount of was added so as to be 15 ppm as a phosphorus atom with respect to the mass of the obtained polyester resin, PET having IV of 0.553 dl / g was obtained. The polycondensation time at this time was 190 minutes in total, and the temperature time product was 5640 ° C. · min.
The evaluation results of the PET thus obtained are shown in Table 1.

Since the polyester resins obtained in Examples 1 to 11 have a Tc1 of 170 ° C. or higher, an optimum Tc1 (for example, 160 to 165 ° C.) can be obtained according to the demand from the market by blending a small amount of the crystalline resin. Can be easily controlled. Moreover, since Tc2 is 175 degrees C or less, the transparency of the molded object obtained is fully satisfactory. Since the polyester resins obtained in Comparative Examples 1 and 2 have low Tc1, Tc1 cannot be freely controlled according to the demand from the market. As shown below, the polyester resin obtained in Comparative Example 4 is difficult to control at an optimum Tc1 (for example, 160 to 165 ° C.). Since the polyester resins obtained in Comparative Examples 3 and 5 have a high Tc2, the transparency of the obtained molded product is not at a satisfactory level.
The ease of control of Tc1 is shown below.

Examples 1 to 11 and Comparative Example 4 in which a SUS pipe having a diameter of 20 cm and a length of 5 m was tilted at 45 degrees (a low-density polyethylene sheet was attached to the lower inner surface side of the pipe). The polyester resin chip obtained in (1) was dropped, and contact treatment was performed to attach a small amount of polyethylene to the surface of the polyester chip. In addition, Tc1 of the target at the time of setting it as the preform of a bottle shall be around 165 degreeC, the length of the polyethylene-type sheet affixed on the piping inner surface is adjusted so that it may become this value, and Tc1 before polyethylene adhesion is 175 degreeC or more Those having a sheet length of 1.5 m, those having a temperature of 170 to 175 ° C. were set to a sheet length of 1.0 m, and those having a sheet length of less than 170 ° C. were set to a sheet length of 30 cm.
A preform was prepared from the polyester resin after the contact treatment by the method (4). Ten preforms were taken out at random, a sample was cut out from the plug portion, and Tc1 was measured. Note that a three-point sample was taken from one preform and Tc1 was measured, and the average value of the three points was defined as Tc1 of the preform. The average, maximum and minimum values of Tc1 of 10 preforms were determined. The results are shown in Table 2.

In Examples 1 to 11, there was little variation with respect to the target Tc1, and a suitable Tc1 could be controlled.
In Comparative Example 4, since Tc1 was slightly low, variation was large with respect to the target Tc1, and suitable Tc1 control could not be performed. This is probably because the amount of polyethylene to be blended was very small, and the adhesion of polyethylene was not stabilized by the contact treatment.

  When the polyester resin of the present invention is used for continuous heat production on a commercial scale, it maintains high transparency of the molded product, and when used in a heat-resistant bottle, the crystallization control of the plug portion When used in a molding sheet, it is possible to provide a polyester that does not easily whiten during heating in molding, which contributes to the industry.

Claims (4)

A polyester resin obtained by using, as a catalyst, an aluminum compound and a phosphorus compound represented by the following chemical formula (formula A), a crystallization temperature (Tc1) at elevated temperature is 170 ° C. or higher, and a crystallization temperature (Tc2) at lowered temperature ) der is 175 ° C. or less is, polyester resins having intrinsic viscosities and wherein 0.35~0.80dl / g der Rukoto.

(In (Formula A), X1 and X2 each represent hydrogen, an alkyl group having 1 to 4 carbon atoms, or a monovalent or higher metal.) The amount of phosphorus atoms of all phosphorus compounds including the phosphorus compound represented by the chemical formula (formula A) contained in the polyester resin and the thermal decomposition product thereof is 20 to 65 ppm relative to the mass of the polyester resin. The polyester resin according to claim 1. The ratio P / Al (molar ratio) of the aluminum atom of the aluminum compound contained in the polyester resin and the phosphorus atom of the total phosphorus compound including the phosphorus compound represented by the chemical formula (formula A) and its thermal decomposition product is 1 The polyester resin according to claim 1, wherein 4 ≦ P / Al ≦ 100. The polyester resin according to claim 1, wherein the polyester contains 85 mol% or more of an ethylene terephthalate structural unit.