JP6487838B2 - Polyester polymerization catalyst, method for producing the same, and method for producing polyester using the same - Google Patents

Description

  The present invention relates to a polyester polymerization catalyst comprising particles containing titanium dioxide. Moreover, it is related with the manufacturing method of polyester using the same. Furthermore, it is related with the manufacturing method of a polyester polymerization catalyst.

  Polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as PET) are excellent in properties such as transparency, mechanical properties, gas barrier properties, and flavor barrier properties. Furthermore, polyester has less concern about residual monomers and harmful additives when formed into molded articles, and is excellent in hygiene and safety. Therefore, taking advantage of these characteristics, polyester is a hollow container for filling juice, soft drinks, seasonings, oils, cosmetics, detergents, beverage cans, etc. Widely used as a coating film for laminated steel plates. In recent years, it has been widely used as an optical film such as a protective film for a liquid crystal display.

  When importance is attached to transparency, a copolymerized PET resin containing a comonomer component is used. In an optical film that requires high transparency, an extrusion blow molded container that requires transparency and moldability, and the like, a PET resin in which a comonomer component is copolymerized depending on the application is used (for example, Patent Document 1 and 2). However, the transparency of these PET resins was not satisfactory.

One of the main factors that decrease the transparency of the polyester resin is a polymerization catalyst. Currently widely used catalysts have their own problems. When antimony oxide (Sb ₂ O ₃ ) is used, since the transparency of the resulting polyester resin is lowered, it is not suitable for applications requiring high transparency. When using an organic titanium catalyst such as titanium (IV) tetraisoproxide, the resulting polyester resin is colored yellow, and the inherent viscosity is lowered due to thermal decomposition during melt molding, and further the coloration proceeds. ing. In addition, when germanium dioxide (GeO ₂ ) is used, the carboxyl group content of the resulting polyester is increased, and a decrease in intrinsic viscosity when the resin is recovered and melt-formed again cannot be avoided, and the catalyst cost is greatly increased. To rise.

  On the other hand, phosphorus compounds, such as phosphorous acid and phosphoric acid, are known as coloring inhibitors used for polyester resins. However, such a coloring inhibitor has a problem of inhibiting the catalytic action of the polyester polymerization catalyst.

  Patent Document 3 reports a composite particle catalyst in which the surface of solid base particles is covered with titanium oxide as a polyester polymerization catalyst, and a high molecular weight polyester having excellent color and transparency by using it. Is supposed to be obtained. However, when a coloring inhibitor is used during the polymerization, there is a problem that the activity of the polymerization catalyst decreases.

JP-A-9-176296 JP-A-6-263893 JP 2006-188567 A

  The present invention has been made in order to solve the above-described problems, and has an object to provide a polyester polymerization catalyst that can obtain a molded article having high catalytic activity and good color tone, and a method for producing the same. To do. Moreover, it aims at providing the manufacturing method of the polyester resin composition using such a polyester polymerization catalyst.

The above problem is solved by providing a polyester polymerization catalyst in which a siloxy group represented by the following formula (1) is bonded to the surface of particles containing titanium dioxide.
R ¹ _{1 + n} SiO _3-n − (1)

In formula (1), R ¹ is a hydrocarbon group having 3 to 30 carbon atoms which may contain a halogen atom, and n is 0, 1 or 2. Further, at least one of oxygen atoms is bonded to the particle surface.

  It is preferable that the molar ratio (Si / Ti) of silicon atoms and titanium atoms contained in the polyester polymerization catalyst is 0.01 to 1.00. The particles containing titanium dioxide are also preferably composite particles of hydrotalcite and titanium dioxide. The composite particles are preferably composed of hydrotalcite 50 to 95% by mass and titanium dioxide 5 to 50% by mass.

  A preferred embodiment of the present invention is a method for producing a polyester resin composition in which an aromatic dicarboxylic acid and an aliphatic diol are polycondensed in the presence of the polyester polymerization catalyst and phosphorous acid or phosphoric acid.

  At this time, it is preferable to polycondensate the said polyester polymerization catalyst using 0.001-0.03 mass part with respect to 100 mass parts of aromatic dicarboxylic acid components. It is also preferable to polycondensate phosphorous acid or phosphoric acid using 0.001-0.1 mass part with respect to 100 mass parts of aromatic dicarboxylic acid components.

The above problem can also be solved by providing a method for producing a polyester polymerization catalyst, in which an alkoxysilane represented by the following formula (2) is reacted with the surface of particles containing titanium dioxide in the presence of water.
R ¹ _{1 + n} Si (OR ² ) _3-n (2)

In the formula (2), R ¹ is a hydrocarbon group having 3 to 30 carbon atoms which may contain a halogen atom, R ² is a hydrocarbon group having 1 to 4 carbon atoms, and n is 0. 1 or 2.

  It is preferable that the molar ratio (Si / Ti) between the silicon atom contained in the alkoxysilane and the titanium atom contained in the particle is 0.01 to 1.00.

  In the manufacturing method, it is preferable that the titanium dioxide-containing particles are dispersed and reacted in an alcohol solution containing the alkoxysilane and water. It is preferable that pH of the said alcohol solution is 1-6.

The above-mentioned problem is a resin composition containing polyester and particles; the polyester contains 25 to 50 mol% of terephthalic acid units, 25 to 49.5 mol% of ethylene glycol units, and 0.5 to 0.5 of diethylene glycol units. 2.5 mol%, and 0-25 mol% of other comonomer units, the intrinsic viscosity of the polyester is 0.5-1.5 dL / g, and the particles are on the surface of the particles containing titanium oxide. The problem can also be solved by providing a polyester resin composition characterized in that it is a particle formed by bonding a siloxy group represented by the following formula (1).
R ¹ _{1 + n} SiO _3-n − (1)

In formula (1), R ¹ is a hydrocarbon group which may contain a halogen atom having 3 to 30 carbon atoms, and n is 0, 1 or 2. Further, at least one of 3-n oxygen atoms is bonded to a titanium atom on the particle surface.

  The polyester comprises 25 to 50 mol% terephthalic acid units, 25 to 49.5 mol% ethylene glycol units, 0.5 to 2.5 mol% diethylene glycol units, and 1.5 to 25 other comonomer units. It is preferable to contain mol%.

  The polyester polymerization catalyst of the present invention has high catalytic activity, and the molded product made of polyester obtained using the polymerization catalyst has good color tone. In particular, when polymerization is performed using the catalyst of the present invention, even when phosphorous acid or phosphoric acid is used in combination as a coloring inhibitor, a decrease in catalytic activity is suppressed. Therefore, a molded article made of a polyester resin having a good color tone and a high molecular weight can be obtained. Moreover, according to the method for producing a polyester polymerization catalyst of the present invention, a polyester polymerization catalyst can be obtained which can obtain a polyester having high catalytic activity and suitable for production of a molded article having a good color tone.

The polyester polymerization catalyst of the present invention is formed by bonding a siloxy group represented by the following formula (1) to the surface of particles containing titanium dioxide.
R ¹ _{1 + n} SiO _3-n − (1)

In formula (1), R ¹ is a hydrocarbon group having 3 to 30 carbon atoms which may contain a halogen atom, and n is 0, 1 or 2. Further, at least one of oxygen atoms is bonded to the particle surface.

  The particles containing titanium dioxide are not particularly limited as long as they contain titanium dioxide, and may be made of titanium dioxide or may contain titanium dioxide and other components. The content of titanium dioxide in the particles is usually 5% by mass or more.

  Examples of the particles containing titanium dioxide include particles made of titanium dioxide, composite particles of hydrotalcite and titanium dioxide, and in particular, from the viewpoint of further improving the color tone of the obtained molded product, hydrotalcite and dioxide. Titanium composite particles are preferred.

  The particle size of the titanium dioxide particles is not particularly limited, but is preferably fine particles having an average particle size of 1 μm or less. The particles made of titanium dioxide can be obtained by a method of hydrolyzing an alkoxy titanate compound. Examples of the titanic acid alkoxy compound include titanium tetraisopropoxide, titanium tetrabutoxide, titanium tetraethoxide and the like.

The composite particles of hydrotalcite and titanium dioxide may have a structure in which titanium dioxide is introduced between the layers of hydrotalcite, and have a structure in which the surface of the hydrotalcite particles is covered with titanium dioxide. It may be. It preferably consists of hydrotalcite 50 to 95% by mass and titanium dioxide 5 to 50% by mass. The particle size is not particularly limited, but is preferably fine particles having an average particle size of 1 μm or less. Hydrotalcite is a compound comprising magnesium and aluminum carbonate and hydroxide, typically having a chemical composition that _{Mg 6 Al 2 (CO 3)} (OH) 16 · 4 (H 2 O).

  The polymerization catalyst of the present invention is formed by bonding a siloxy group represented by the above formula (1) to the surface of the particles containing titanium dioxide. When at least one of the oxygen atoms in the siloxy group represented by the formula (1) is bonded to the particle surface containing titanium dioxide, the siloxy group is bonded to the particle surface. From the viewpoint of bond stability, it is preferable that at least one of oxygen atoms in the siloxy group is bonded to a titanium atom on the particle surface.

R ¹ in the siloxy group represented by the above (1) is a hydrocarbon group having 3 to 30 carbon atoms which may contain a halogen atom. When the number of carbon atoms is less than 3, when the polymerization is performed using the polymerization catalyst and phosphorous acid or phosphoric acid, the catalytic activity becomes insufficient. The number of carbon atoms is preferably 4 or more, and more preferably 6 or more. On the other hand, when the carbon number exceeds 30, the catalytic activity becomes insufficient. The carbon number is preferably 20 or less, and more preferably 16 or less.

The hydrocarbon group used as R ¹ is propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, tert-pentyl group, hexyl group, isohexyl. Group, 2-ethylhexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group and other linear and branched alkyl groups, phenyl group, benzyl group, tolyl group and the like. Of these, a decyl group, a dodecyl group, and the like are preferable.

  Examples of the halogen atom in the hydrocarbon group include chlorine, fluorine, bromine and iodine.

  N in the siloxy group represented by the above (1) is 0, 1 or 2. From the viewpoint of reactivity, n is preferably 0.

It is a major feature of the present invention that such a siloxy group is bonded to the surface of the particles containing titanium dioxide. The polymerization catalyst of the present invention having such a structure has high catalytic activity, and a molded product made of polyester obtained using the polymerization catalyst has a good color tone. In particular, when polymerization is performed using the catalyst of the present invention, even when phosphorous acid or phosphoric acid is used in combination as a coloring inhibitor, since the decrease in catalytic activity is suppressed, it has a good color tone and has a molecular weight. A molded article made of a high polyester resin is obtained. Moreover, highly transparent polyester is obtained by using the particle | grains containing a titanium dioxide as a polymerization catalyst. Although the mechanism for obtaining such an effect is not clear, the following may be considered. Due to the low polarity hydrocarbon group represented by R ¹ in the siloxy group, the approach of highly polar phosphorous acid or phosphoric acid to the catalyst particles is suppressed. Therefore, it is thought that the fall of the catalyst activity by using these coloring inhibitors is suppressed. On the other hand, since raw material monomers and polyesters have low polarity, it is considered that the binding to these catalyst particles is not inhibited and high catalytic activity is maintained.

  Of the oxygen atoms in the siloxy group represented by the above formula (1), those not bonded to the particle surface may be bonded to other siloxy groups to form the following structure. For example, the siloxane groups may be bonded to each other when oxygen atoms in the siloxy groups form siloxane bonds (Si—O—Si). In some cases, a group derived from a raw material is directly bonded to a carbon atom in the siloxy group. For example, when the polyester polymerization catalyst is produced using alkoxysilane, the alkyl group derived from the alkoxysilane may be bonded as it is.

  The molar ratio (Si / Ti) of silicon atoms and titanium atoms contained in the polyester polymerization catalyst of the present invention is preferably 0.01 to 1.00, more preferably 0.01 to 0.50. Here, the silicon atom is mainly contained in the siloxy group represented by the above formula (1). On the other hand, titanium atoms are mainly derived from the titanium dioxide of the particles. The amount of titanium dioxide correlates with the catalyst activity. The molar ratio of silicon atom to titanium atom (Si / Ti) indicates the molar ratio of titanium dioxide in the polymerization catalyst to the siloxy group represented by the above formula (1). When the molar ratio (Si / Ti) is in the above range, the balance between the catalytic activity and the color tone of the obtained molded product is further improved.

  The polyester polymerization catalyst of this invention can be manufactured with the manufacturing method of the polyester polymerization catalyst etc. which are mentioned later.

  A preferred embodiment of the present invention is a method for producing a polyester resin composition in which an aromatic dicarboxylic acid and an aliphatic diol are polycondensed in the presence of the polyester polymerization catalyst and phosphorous acid or phosphoric acid. As described above, when polymerization is carried out using the catalyst of the present invention, even when phosphorous acid or phosphoric acid is used in combination as a coloring inhibitor, a decrease in the activity of the catalyst is suppressed, so that it has a good color tone. In addition, a molded article made of a polyester resin having a high molecular weight can be obtained.

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, biphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, sodium sulfoisophthalate, 2,6-naphthalenedicarboxylic acid, 1, Examples include aromatic dicarboxylic acids such as 4-naphthalenedicarboxylic acid and 2,7-naphthalenedicarboxylic acid. These may be used alone or in combination of two or more. Instead of the aromatic dicarboxylic acid, an ester-forming derivative thereof may be used.

  In the method for producing the polyester resin composition, a dicarboxylic acid other than an aromatic dicarboxylic acid or an ester-forming derivative thereof may be used. For example, glutaric acid, adipic acid, azelaic acid, sebacic acid, dimer Aliphatic dicarboxylic acids such as acids (and their hydrogenated products) and ester-forming derivatives thereof; cycloaliphatic dicarboxylic acids, norbornene dicarboxylic acids, tricyclodecanedicarboxylic acids and other alicyclic dicarboxylic acids and their ester-forming derivatives It is done.

  In the manufacturing method of the said polyester resin composition, it is preferable that content of a terephthalic acid unit is 25-50 mol% with respect to all the monomer units in the polyester obtained.

  Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, and methylpentanediol. These may be used alone or in combination of two or more.

  In the method for producing the polyester resin composition, a diol other than the aliphatic diol may be used. Other diols include cycloaliphatic diols such as cyclohexanedimethanol, norbornene dimethanol, and tricyclodecane dimethanol. A diol in which one or more molecules of ethylene oxide are added to two hydroxyl groups of an aromatic diol can also be used. For example, diols in which 1 to 8 molecules of ethylene oxide are added to the two phenolic hydroxyl groups of bisphenol A can be exemplified.

  In the manufacturing method of the said polyester resin composition, it is preferable that content of an ethylene glycol unit is 25-49.5 mol% with respect to all the monomer units in polyester obtained.

  In the manufacturing method of the said polyester resin composition, you may further use other bifunctional compounds other than dicarboxylic acid and diol. Examples of other bifunctional compounds include hydroxycarboxylic acid and ester-forming derivatives thereof. Furthermore, a polyfunctional compound having three or more carboxyl groups, hydroxyl groups, or ester-forming groups thereof, or a monofunctional compound that is a monocarboxylic acid, a monoalcohol, or an ester-forming derivative thereof may be used in combination.

  Hydroxycarboxylic acids and ester-forming derivatives thereof include aliphatic hydroxycarboxylic acids such as 10-hydroxyoctadecanoic acid or ester-forming derivatives thereof; hydroxymethylcyclohexanecarboxylic acid, hydroxymethylnorbornenecarboxylic acid, hydroxymethyltricyclodecanecarboxylic acid Alicyclic hydroxycarboxylic acids such as acids or ester-forming derivatives thereof; hydroxybenzoic acid, hydroxytoluic acid, hydroxynaphthoic acid, 3- (hydroxyphenyl) propionic acid, hydroxyphenylacetic acid, 3-hydroxy-3-phenylpropion Aromatic hydroxycarboxylic acids such as acids and their ester-forming derivatives.

  Examples of the polyfunctional compound having three or more carboxyl groups, hydroxyl groups, or ester-forming groups thereof include trimellitic acid, pyromellitic acid, trimesic acid, trimethylolpropane, pentaerythritol, and ester-forming derivatives thereof. These can be added in a small amount to increase the melt tension and can be used to adjust the melt extrusion moldability. The content of the unit derived from the polyfunctional compound is preferably 1 mol% or less, and more preferably 0.5 mol% or less, based on all monomer units in the polyester. If the ratio of the polyfunctional compound unit exceeds 1 mol%, gelation tends to occur, which is not preferable.

  Examples of monofunctional compounds having only one carboxyl group, hydroxyl group or ester forming group thereof include benzoic acid, 2,4,6-trimethoxybenzoic acid, 2-naphthoic acid, stearic acid, and stearyl alcohol. . These function as sealing monomer units, seal molecular chain end groups in the polyester, and may be blended to prevent excessive crosslinking and gel formation in the polyester. The content of the unit derived from the monofunctional compound is preferably 1 mol% or less, and more preferably 0.5 mol% or less, based on all monomer units in the polyester. When the ratio of the monofunctional compound unit exceeds 1 mol%, the polymerization rate in producing the polyester is slowed, and the productivity tends to be lowered.

In the method for producing the polyester resin composition, first, an aromatic dicarboxylic acid and an aliphatic diol are heated to advance an esterification reaction or a transesterification reaction to obtain an oligomer. When other monomers other than the aromatic dicarboxylic acid and the aliphatic diol are used, other monomers may be added in advance, and an oligomer may be obtained by simultaneously proceeding an esterification reaction or a transesterification reaction. After obtaining an oligomer, another monomer may be added and subjected to a melt polymerization reaction. The esterification reaction or transesterification reaction is preferably carried out at a temperature of 180 to 300 ° C. while distilling off the produced water or alcohol under an absolute pressure of about 5 kg / cm ² or less or at normal pressure. The raw material ratio in the esterification reaction or transesterification reaction is preferably such that the molar ratio (diol component / dicarboxylic acid component) is in the range of 1.1 to 2.5.

  When the esterification reaction is carried out using terephthalic acid, the reaction can be carried out without a catalyst. On the other hand, when the transesterification is performed using dimethyl terephthalate, one or more metal compounds such as calcium, manganese, magnesium, zinc, titanium, sodium, and lithium are preferably used as the transesterification catalyst. However, in order to prevent unnecessary fine particles from remaining in the obtained pellet, it is preferable to perform the esterification reaction without using a transesterification catalyst. When the esterification reaction is allowed to proceed, the polymerization catalyst of the present invention can be added in advance, but in the case of further solid-phase polymerization after melt polycondensation, the polymerization catalyst is added after the esterification reaction is completed. Then, it is preferable to use it for the subsequent melt polymerization reaction because the preliminary crystallization rate increases.

  The melt polycondensation reaction following the esterification reaction or transesterification reaction is performed in the presence of the polyester polymerization catalyst of the present invention and phosphorous acid or phosphoric acid. Here, it is important to use at least one of phosphorous acid and phosphoric acid. These function as an anti-coloring agent and reduce coloring during polymerization and molding of the obtained polyester resin. The polyester polymerization catalyst of the present invention has high catalytic activity even when such an anti-coloring agent is used in combination. Therefore, a molded article made of a polyester resin having a good color tone and a high molecular weight can be obtained.

  The phosphoric acid may be polyphosphoric acid formed by condensing a plurality of phosphoric acids.

  It is preferable that the usage-amount of the said polymerization catalyst is 0.001-0.03 mass part with respect to 100 mass parts of aromatic dicarboxylic acid components. When the amount of the catalyst used is too small, the polymerization reaction rate decreases. The amount of the catalyst used is more preferably 0.002 parts by mass or more. On the other hand, when the amount of the catalyst used is too large, the pressure increase rate of the filter used during extrusion molding increases. The amount of the catalyst used is more preferably 0.02 parts by mass or less, and further preferably 0.015 parts by mass or less.

  Moreover, it is preferable that the total usage-amount of phosphoric acid and phosphorous acid is 0.001-0.1 mass part with respect to 100 mass parts of aromatic dicarboxylic acid components. When the said usage-amount is less than 0.001 mass part, there exists a possibility that the color tone of a molded article may deteriorate. As for the said usage-amount, 0.003 mass part or more is more preferable. On the other hand, when the amount used exceeds 0.1 parts by mass, the activity of the polymerization catalyst becomes insufficient, and it may be difficult to obtain a high molecular weight polyester, or the productivity may decrease. As for the said usage-amount, 0.05 mass part or less is more preferable.

  Furthermore, in order to suppress coloring due to thermal decomposition of the polyester, 0.001 to 0.5 parts by mass of a cobalt compound such as cobalt acetate can be added to 100 parts by mass of the aromatic dicarboxylic acid component.

  The intrinsic viscosity of the polyester obtained by melt polycondensation is preferably in the range of 0.4 to 0.85 dL / g from the viewpoint of handleability. When the intrinsic viscosity of the polyester obtained by melt polycondensation is less than 0.4 dL / g, when the polyester is taken out from the reactor, the melt viscosity is too low and it becomes difficult to extrude in the form of a strand or a sheet, Moreover, it becomes difficult to cut into pellets uniformly. Furthermore, when solid-phase polymerization is performed, it takes a long time to increase the molecular weight, resulting in a decrease in productivity. The intrinsic viscosity is more preferably 0.5 dL / g or more. On the other hand, if the intrinsic viscosity of the polyester is higher than 0.85 dL / g, the melt viscosity is too high, so that it is difficult to take out the polyester from the reactor, and coloration due to thermal deterioration tends to occur. The intrinsic viscosity is more preferably 0.8 dL / g or less, and still more preferably 0.75 dL / g or less.

  In the method for producing a polyester resin composition, it is preferable to solid-phase polymerize a polyester obtained by melt polycondensation in order to obtain a high amount of polyester.

  The polyester obtained by melt polymerization as described above is extruded into a strand shape, a sheet shape, and the like, cooled, and then cut with a strand cutter or a sheet cutter to obtain a cylindrical shape, an elliptical column shape, a disk shape, a die shape. Amorphous pellets of the shape such as are manufactured. The above-described cooling after extrusion can be performed by, for example, a water cooling method using a water tank, a method using a cooling drum, an air cooling method, or the like.

  The amorphous pellet thus obtained is preferably heated in a temperature range of 100 to 160 ° C. and preliminarily crystallized before being subjected to solid phase polymerization. If it is not pre-crystallized, the pellets will easily stick together during solid phase polymerization. As a precrystallization method, crystallization may be performed in a vacuum tumbler, or crystallization may be performed by heating in an air circulation type heating apparatus. The time required for the preliminary crystallization is not particularly limited, but is usually about 30 minutes to 24 hours. Prior to precrystallization, the pellets may be dried at a temperature below 100 ° C.

  The amorphous pellets used for the precrystallization may be a blend of two or more kinds of polyesters. For example, amorphous pellets obtained by melt-kneading two or more kinds of polyester pellets obtained by melt polymerization can be subjected to preliminary crystallization. In this case, what is necessary is just to satisfy the ratio of the monomer unit contained, a polymerization degree, etc. as the whole amorphous pellet obtained by blending. In addition, the pellets obtained by pre-crystallizing the amorphous pellets and solid-phase polymerization may satisfy the conditions defined by the present invention as a whole.

  Solid phase polymerization of the precrystallized pellet is preferably performed under reduced pressure or in an inert gas such as nitrogen gas. Further, it is preferable to carry out solid phase polymerization while moving the pellets by an appropriate method such as a rolling method or a gas fluidized bed method so that no sticking occurs between the pellets of the polyester resin composition. Among these, it is preferable to perform solid-state polymerization under reduced pressure. The pressure when solid-state polymerization is performed under reduced pressure is preferably 10 kPa or less, and more preferably 1 kPa or less.

  The solid state polymerization temperature is preferably 170 to 230 ° C. When the solid-phase polymerization temperature is less than 170 ° C., the solid-phase polymerization time becomes long and the productivity may be lowered. The solid state polymerization temperature is more preferably 180 ° C. or higher. On the other hand, when the solid phase polymerization temperature exceeds 230 ° C., the pellets may be stuck. The solid state polymerization temperature is more preferably 220 ° C. or lower, and further preferably 210 ° C. or lower. The solid phase polymerization time is usually about 5 to 70 hours.

  The intrinsic viscosity of the polyester after solid phase polymerization is preferably 0.75 to 1.5 dL / g. When the intrinsic viscosity is less than 0.75 dL / g, the strength, impact resistance and transparency of the obtained molded product may be lowered. The intrinsic viscosity is more preferably 0.8 dL / g or more. On the other hand, when the intrinsic viscosity exceeds 1.5 dL / g, the melt viscosity becomes too high, the melt moldability is lowered, and the productivity is also lowered. The intrinsic viscosity is more preferably 1.4 dL / g or less, and even more preferably 1.3 dL / g or less. The intrinsic viscosity of the polyester after the solid phase polymerization is preferably 1.15 times or more, more preferably 1.2 times or more, more preferably 1.25 times or more of the intrinsic viscosity of the polyester before melt kneading. More preferably.

  The content of the particles containing titanium dioxide contained in the polyester resin composition obtained by the production method is preferably 10 to 300 ppm. If the content of the double particle as a polymerization catalyst is too small, a high molecular weight polyester may not be obtained. The content of the particles is more preferably 20 ppm or more, and even more preferably 30 ppm or more. On the other hand, when there is too much content of the said particle | grains, there exists a possibility that a color tone may deteriorate. The content of the particles is more preferably 200 ppm or less, and even more preferably 140 ppm or less. The content of the particles can be calculated from the amount of the polymerization catalyst added to the aromatic dicarboxylic acid component.

  The polyester resin composition thus obtained may contain resin components other than polyester as long as the effects of the present invention are not impaired. However, the content is usually 5% by mass or less, preferably 1% by mass, and more preferably substantially not contained. The crystal pellet of the present invention may contain inorganic particles other than the polyester polymerization catalyst of the present invention as long as the effects of the present invention are not impaired. However, the content is usually 1000 ppm or less, preferably 100 ppm or less, and more preferably substantially free.

A resin composition containing polyester and particles, wherein the polyester comprises 25 to 50 mol% terephthalic acid units, 25 to 49.5 mol% ethylene glycol units, and 0.5 to 2.5 mol diethylene glycol units. %, And 0 to 25 mol% of other comonomer units, the intrinsic viscosity of the polyester is 0.5 to 1.5 dL / g, and the particles have the following formula (1 The particles formed by bonding siloxy groups represented by () are preferable because of good color tone and high molecular weight.
R ¹ _{1 + n} SiO _3-n − (1)

In formula (1), R ¹ is a hydrocarbon group which may contain a halogen atom having 3 to 30 carbon atoms, and n is 0, 1 or 2. Further, at least one of 3-n oxygen atoms is bonded to a titanium atom on the particle surface.

  Such a resin composition can be manufactured with the manufacturing method of the polyester resin composition mentioned above.

  The polyester comprises 25 to 50 mol% terephthalic acid units, 25 to 49.5 mol% ethylene glycol units, 0.5 to 2.5 mol% diethylene glycol units, and 1.5 to 25 other comonomer units. It is preferable to contain mol%.

The method for producing a polyester polymerization catalyst of the present invention is a method in which an alkoxysilane represented by the following formula (2) is reacted with the surface of particles containing titanium dioxide in the presence of water.
R ¹ _{1 + n} Si (OR ² ) _3-n (2)

In the formula (2), R ¹ is a hydrocarbon group having 3 to 30 carbon atoms which may contain a halogen atom, R ² is a hydrocarbon group having 1 to 4 carbon atoms, and n is 0. 1 or 2.

  Moreover, the polyester polymerization catalyst obtained by making the alkoxysilane shown by said Formula (2) react on the surface of the particle | grains containing titanium dioxide in presence of water also has high catalytic activity, and also uses the said polymerization catalyst. A molded article made of polyester obtained in this manner is preferably used because it has a good color tone.

  The particles containing titanium dioxide are not particularly limited as long as they contain titanium dioxide, and may be made of titanium dioxide or may contain titanium dioxide and other components. The content of titanium dioxide in the particles is usually 5% by mass or more.

  Examples of the particles containing titanium dioxide include particles made of titanium dioxide and composite particles of hydrotalcite and titanium dioxide. Particles made of titanium dioxide and composite particles of hydrotalcite and titanium dioxide are preferred, and the latter is more preferred from the viewpoint of further improving the color tone of the obtained molded product.

  The particle size of the titanium dioxide particles is not particularly limited, but is preferably fine particles having an average particle size of 1 μm or less. The particles made of titanium dioxide can be obtained by a method of hydrolyzing an alkoxy titanate compound. Examples of the titanate alkoxy compound include titanium tetraisopropylate, titanium tetrabutyrate, titanium tetraethylate, and the like.

The composite particles of hydrotalcite and titanium dioxide may have a structure in which titanium dioxide is introduced between the layers of hydrotalcite, and have a structure in which the surface of the hydrotalcite particles is covered with titanium dioxide. It may be. It preferably consists of hydrotalcite 50 to 95% by mass and titanium dioxide 5 to 50% by mass. The particle size is not particularly limited, but is preferably fine particles having an average particle size of 1 μm or less. Hydrotalcite is a compound comprising magnesium and aluminum carbonate and hydroxide, typically having a chemical composition that _{Mg 6 Al 2 (CO 3)} (OH) 16 · 4 (H 2 O).

In the above formula (2), R ¹ is the number of carbon atoms, which may contain a halogen atom is a hydrocarbon group of 3 to 30. When the number of carbon atoms is less than 3, the catalytic activity becomes insufficient when polymerization is carried out using the resulting polymerization catalyst and phosphorous acid or phosphoric acid. The number of carbon atoms is preferably 4 or more, and more preferably 6 or more. On the other hand, when the carbon number exceeds 30, the activity of the resulting polymerization catalyst becomes insufficient. The carbon number is preferably 20 or less, and more preferably 16 or less.

The hydrocarbon group used as R ¹ is propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, tert-pentyl group, hexyl group, isohexyl. Group, 2-ethylhexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group and other linear and branched alkyl groups, phenyl group, benzyl group, tolyl group and the like. Of these, a decyl group, a dodecyl group, and the like are preferable.

  Examples of the halogen atom in the hydrocarbon group include chlorine, fluorine, bromine and iodine.

  N in the alkoxysilane represented by the above formula (2) is 0, 1 or 2.

  Examples of the alkoxysilane represented by the above formula (2) include phenyltrimethoxysilane (KBM-103, manufactured by Shin-Etsu Chemical Co., Ltd.), n-propyltrimethoxysilane (KBM-3033, manufactured by Shin-Etsu Chemical Co., Ltd.), n -Propyltriethoxysilane (KBE-3033, manufactured by Shin-Etsu Chemical Co., Ltd.), hexyltrimethoxysilane (KBM-3063, manufactured by Shin-Etsu Chemical Co., Ltd.), hexyltriethoxysilane (KBE-3063, manufactured by Shin-Etsu Chemical Co., Ltd.) ), Octyltriethoxysilane (KBE-3083, manufactured by Shin-Etsu Chemical Co., Ltd.), decyltrimethoxysilane (KBM-3103C, manufactured by Shin-Etsu Chemical Co., Ltd.), dodecyltrimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.), tri Fluoropropyltrimethoxysilane (KBM-7103 They include Shin-Etsu Chemical Co., Ltd.), among others, decyl trimethoxysilane, dodecyl trimethoxy silane are preferred.

  The alkoxysilane represented by the above formula (2) is reacted with the surface of the particles containing titanium dioxide in the presence of water. When the hydrolyzate obtained by hydrolyzing the alkoxysilane is bonded to the particle surface, the particles are surface-treated.

  At this time, it is preferable that the particles containing titanium dioxide are dispersed in a solution containing the alkoxysilane and water to react the alkoxysilane with the particles. From the viewpoint of the reactivity of the alkoxysilane, the solution preferably has a pH of 1-6. The method for adjusting the pH of the solution is not particularly limited, and can be adjusted by adding an acid such as hydrochloric acid, acetic acid, oxalic acid, phosphoric acid, phosphorous acid or the like. Examples of the liquid medium used at this time include polar solvents such as alcohol, N, N-dimethylformamide, acetone, and dimethyl sulfoxide, and alcohol is preferable. That is, it is preferable that the particles containing titanium dioxide are dispersed and reacted in an alcohol solution containing the alkoxysilane and water. Examples of the alcohol include ethylene glycol and ethanol.

  When reacting the alkoxysilane and the particles, it is preferable that the molar ratio (Si / Ti) of silicon atoms contained in the alkoxysilane and titanium atoms contained in the particles is 0.01 to 1.00. . When the molar ratio (Si / Ti) is in the above range, the balance between the catalytic activity and the color tone of the obtained molded product is further improved.

  The temperature and time when the alkoxysilane represented by the above formula (2) is reacted with the surface of the particles containing titanium dioxide are not particularly limited, but the reaction temperature is usually 5 to 40 ° C., and the reaction time is 0.5 to 6 hours.

  The polyester polymerization catalyst of the present invention has high catalytic activity, and a molded product made of polyester obtained using the polymerization catalyst has a good color tone. In particular, when polymerization is performed using the catalyst of the present invention, even when phosphorous acid or phosphoric acid is used in combination as a coloring inhibitor, a decrease in catalytic activity is suppressed. Therefore, a molded article made of a polyester resin having a good color tone and a high molecular weight can be obtained. Molded products obtained in this way include hollow containers for filling juices, soft drinks, seasonings, oils, cosmetics, detergents, etc., coated films of laminated steel plates such as beverage cans, optical films such as protective films for liquid crystal displays, etc. As widely used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by this Example.

(1) Intrinsic viscosity The intrinsic viscosity of the polyester in the amorphous pellets and the crystal pellets after solid-phase polymerization is a temperature of 30 ° C. using an equal mass mixture of phenol and 1,1,2,2-tetrachloroethane as a solvent. Measured with Since the mass of the particles contained in the pellet was very small, it was ignored.

(2) b value of pellet after solid phase polymerization The resin color (b value) of the crystal pellet after solid phase polymerization is measured by Nippon Denshoku Industries Co., Ltd. according to ASTM-D2244 (color scale system 2). Measurement was performed using a color difference meter “ZE-2000”.
(3) b value of molded product Injection molding was performed under the conditions of a cylinder temperature of 260 ° C to 270 ° C using pellets obtained by solid phase polymerization to obtain a transparent plate (10 cm square). This was crystallized at 120 ° C. for 1 hour under vacuum, and then the b value was measured in the same manner as the crystal pellet after solid phase polymerization.
(4) Coloring during molding From the difference between the b value of the pellet after solid phase polymerization measured in (2) above and the b value of the molded product measured in (3) above, the following evaluation was performed.
A: (b value of molded product) − (b value of pellet after solid phase polymerization) <6
B: (b value of molded product) − (b value of pellet after solid phase polymerization) ≧ 6

Example 1
(1) Preparation of Catalyst A After adding 1 mg of phosphorous acid and 10 mL of ethylene glycol to a 50 mL flask, a pH 4 solution was prepared by stirring at room temperature. After mixing 0.3 g of ion exchange water and 1.0 g of dodecyltrimethoxysilane, the mixture was stirred for 1 hour. After confirming the disappearance of dodecyltrimethoxysilane by gas chromatograph (manufactured by Shimadzu Corporation), the reaction solution was transferred to a 300 mL flask, and “SATICA SPC-”, which is an ethylene glycol dispersion of composite particles of hydrotalcite and titanium dioxide. 124-20 "(manufactured by Sakai Chemical Industry Co., Ltd.) 25.0 g (of which 5.0 g of composite particles as a polymerization catalyst and 20.0 g of ethylene glycol) and 90 mL of ethylene glycol were added. After stirring at room temperature for 4 hours, the reaction was slowly added into vigorously stirred acetone for reprecipitation. After standing, the mixture in which a white precipitate was produced was subjected to suction filtration, and the white solid on the filter paper was again added to acetone and dispersed by sonication. The dispersion was suction filtered again, and the white solid on the filter paper was vacuum-dried at 120 ° C. for 5 hours to obtain white catalyst A (3.2 g). When the catalyst A was analyzed by X-ray photoelectron spectroscopy (XPS), the peaks of 458 eV and 464 eV derived from Ti (2p), the peak of 102 eV derived from Si (2p), the peak of 285 eV derived from C (1s), A peak of 532 eV derived from O (1s) was confirmed. The catalyst A was analyzed for the amount of titanium element and the amount of silicon element by ICP emission spectroscopic analysis. The molar ratio of these elements was Si / Ti = 0.3.

(2) Melt polycondensation A slurry consisting of 95.0 parts by mass of terephthalic acid (TA), 5.0 parts by mass of isophthalic acid (IPA) and 44.8 parts by mass of ethylene glycol (EG) is prepared under pressure (gauge pressure 0 The oligomer was produced by heating to 250 ° C. at a temperature of 250 MPa for esterification reaction. The obtained oligomer was transferred to a polycondensation tank, and 0.006 parts by mass of catalyst A (mass of composite particles excluding components derived from dodecyltrimethoxysilane) and 0.006 parts by mass of phosphorous acid were added thereto. Polyester having an intrinsic viscosity of 0.60 dL / g was produced by melt polycondensation at 0.1 kPa and 280 ° C. for 170 minutes. The obtained polyester was extruded into a strand form from a nozzle and cooled with water, and then cut into a cylindrical shape (diameter: about 2.5 mm, length: about 2.5 mm) to obtain an amorphous pellet of polyester.

(3) Precrystallization of amorphous pellets The polyester amorphous pellets obtained as described above were put into a rolling vacuum solid phase polymerization apparatus and precrystallized at 120 ° C for 10 hours under 0.1 kPa. went.

(4) Solid Phase Polymerization After the preliminary crystallization, the temperature was increased and solid phase polymerization was performed at 200 ° C. under 0.1 kPa for 18 hours to obtain crystal pellets. The intrinsic viscosity of the obtained copolyester was 0.81 dL / g. The resin color (b value) of the crystal pellet after the solid phase polymerization was 5. The b value of the molded product was 7.

Example 2
Preparation of Catalyst B To a 1000 mL eggplant flask, 250 mL of ethanol and 30.05 g (100 mmol) of titanium (IV) tetraisopropylate were added, and a mixed solution of 54.0 g (3.0 mol) of distilled water and 250 mL of ethanol was added while stirring. The solution was slowly added dropwise at room temperature, followed by further stirring for 1 hour at room temperature. Reprecipitation was performed with 2000 mL of water, and after standing, the operation of removing the supernatant by decantation was repeated twice. The liquid containing the precipitate was suction filtered, and the white solid on the filter paper was washed with water. By drying overnight in a vacuum dryer at 70 ° C., 7.00 g of white powder of titanium oxide (the number average particle diameter of 100 particles arbitrarily selected as measured by a transmission electron microscope, 0.3 μm) was obtained. Among them, 5.00 g of titanium oxide was dispersed in 100 mL of ethylene glycol using ultrasonic treatment. Except that this dispersion was used instead of 25.00 g of “SATICA SPC-124-20”, the same surface treatment as in Example 1 was performed to obtain 5.17 g of white powder catalyst B. The catalyst B was analyzed for the amount of titanium element and the amount of silicon element by ICP emission spectrometry, and the molar ratio of these elements was Si / Ti = 0.05.

  Except that 0.003 part by mass of catalyst B was added instead of catalyst A, the amount of phosphorous acid was 0.003 part by mass, and the melt polymerization time was 220 minutes, the same as in Example 1. Crystal pellets were manufactured and evaluated. The results are summarized in Table 1.

Example 3
Crystal pellets are produced in the same manner as in Example 1 except that the amount of catalyst A is 0.012 parts by mass, the amount of phosphorous acid is 0.012 parts by mass, and the melt polymerization time is 87 minutes. And evaluated. The results are summarized in Table 1.

Example 4
Crystal pellets were produced and evaluated in the same manner as in Example 3 except that phosphoric acid was used instead of phosphorous acid when the melt polycondensation was performed, and the melt polymerization time was changed to 80 minutes. The results are summarized in Table 1.

Comparative Example 1
Crystal pellets were obtained in the same manner as in Example 1, except that 0.006 parts by mass (converted to solid content) of “SATICA SPC-124-20” was used instead of catalyst A, and the melt polymerization time was 172 minutes. Manufactured and evaluated. The results are summarized in Table 1.

Comparative Example 2
Catalyst C was obtained in the same manner as in Example 1 except that the pH of the ethylene glycol solution containing phosphorous acid used for preparing the catalyst was set to 7. The catalyst C was analyzed for the amount of titanium element and the amount of silicon element by ICP emission spectrometry. The molar ratio of these elements was Si / Ti = 0.003. Crystal pellets were produced and evaluated in the same manner as in Example 1 except that the catalyst C was used instead of the catalyst A. The results are summarized in Table 1.

Comparative Example 3
A white powder of titanium oxide was obtained in the same manner as in Example 2. Crystal pellets were produced and evaluated in the same manner as in Example 1 except that the titanium oxide was used in place of the catalyst B. The results are summarized in Table 1.

Comparative Example 4
Crystal pellets were obtained in the same manner as in Example 3 except that 0.012 parts by mass (converted to solid content) of “SATICA SPC-124-20” was used instead of catalyst A, and the melt polymerization time was 74 minutes. Manufactured and evaluated. The results are summarized in Table 1.

Comparative Example 5
Except that 0.006 parts by mass (in terms of solid content) of “SATICA SPC-124-20” was used in place of catalyst A, phosphorous acid was not added, and the melt polymerization time was 73 minutes. Crystal pellets were produced and evaluated in the same manner as in Example 1. The results are summarized in Table 1.

Comparative Example 6
A white powder of titanium oxide was obtained in the same manner as in Example 2. Crystal pellets were produced and evaluated in the same manner as in Example 2 except that the titanium oxide was used in place of the catalyst B, phosphorous acid was not added, and the melt polymerization time was 219 minutes. . The results are summarized in Table 1.

Comparative Example 7
Except that 0.012 parts by mass (in terms of solid content) of “SATICA SPC-124-20” was used in place of catalyst A, phosphorous acid was not added, and the melt polymerization time was 51 minutes. Crystal pellets were produced and evaluated in the same manner as in Example 3. The results are summarized in Table 1.

Claims (13)

A polyester polymerization catalyst formed by bonding a siloxy group represented by the following formula (1) to the surface of particles containing titanium dioxide.
R ¹ _{1 + n} SiO _3-n − (1)
In formula (1), R ¹ is a hydrocarbon group having 3 to 30 carbon atoms which may contain a halogen atom, and n is 0, 1 or 2. Further, at least one of oxygen atoms is bonded to the particle surface.   The polyester polymerization catalyst according to claim 1, wherein the molar ratio (Si / Ti) of silicon atoms and titanium atoms contained is 0.01 to 1.00.   The polyester polymerization catalyst according to claim 1 or 2, wherein the particles containing titanium dioxide are composite particles of hydrotalcite and titanium dioxide.   The polyester polymerization catalyst according to claim 3, wherein the composite particles are composed of hydrotalcite 50 to 95% by mass and titanium dioxide 5 to 50% by mass. The manufacturing method of the polyester polymerization catalyst which makes the alkoxysilane shown by following formula (2) react in the presence of water on the surface of the particle | grains containing titanium dioxide.
R ¹ _{1 + n} Si (OR ² ) _3-n (2)
In the formula (2), R ¹ is a hydrocarbon group having 3 to 30 carbon atoms which may contain a halogen atom, R ² is a hydrocarbon group having 1 to 4 carbon atoms, and n is 0. 1 or 2.   The method for producing a polyester polymerization catalyst according to claim 5, wherein a molar ratio (Si / Ti) between a silicon atom contained in the alkoxysilane and a titanium atom contained in the particle is 0.01 to 1.00.   The method for producing a polyester polymerization catalyst according to claim 5 or 6, wherein the particles containing titanium dioxide are dispersed and reacted in an alcohol solution containing the alkoxysilane and water.   The manufacturing method of the polyester polymerization catalyst of Claim 7 whose pH of the said alcohol solution is 1-6.   The manufacturing method of the polyester resin composition which polycondenses an aromatic dicarboxylic acid and aliphatic diol in presence of the polyester polymerization catalyst in any one of Claims 1-4, and phosphorous acid or phosphoric acid.   The manufacturing method of the polyester resin composition of Claim 9 which polycondenses the said polyester polymerization catalyst using 0.001-0.03 mass part with respect to 100 mass parts of aromatic dicarboxylic acid components.   The manufacturing method of the polyester resin composition of Claim 9 or 10 which polycondenses phosphorous acid or phosphoric acid using 0.001-0.1 mass part with respect to 100 mass parts of aromatic dicarboxylic acid components. . A resin composition comprising polyester and particles;
The polyester has 25-50 mol% terephthalic acid units, 25-49.5 mol% ethylene glycol units, 0.5-2.5 mol% diethylene glycol units, and 0-25 mol% other comonomer units. Contains,
The polyester has an intrinsic viscosity of 0.5 to 1.5 dL / g,
The polyester resin composition, wherein the particles are particles formed by bonding a siloxy group represented by the following formula (1) to the surface of particles containing titanium oxide.
R ¹ _{1 + n} SiO _3-n − (1)
In formula (1), R ¹ is a hydrocarbon group which may contain a halogen atom having 3 to 30 carbon atoms, and n is 0, 1 or 2. Further, at least one of 3-n oxygen atoms is bonded to a titanium atom on the particle surface.   The polyester comprises 25 to 50 mol% terephthalic acid units, 25 to 49.5 mol% ethylene glycol units, 0.5 to 2.5 mol% diethylene glycol units, and 1.5 to 25 other comonomer units. The polyester resin composition according to claim 12, which is contained in mol%.