JP5998541B2 - Method for producing polyester composition - Google Patents

Description

  The present invention relates to a method for producing a polyester composition suitable for use as a film for solar cells, which is inexpensive, has few foreign matters, and has excellent hydrolysis resistance, UV resistance and mat feeling.

  Polyester is excellent in mechanical properties, thermal properties, chemical resistance, electrical properties, and moldability, and is used in various applications.

  However, since the mechanical properties of polyester decrease due to hydrolysis, various studies have been made to suppress hydrolysis when used over a long period of time or when used in a damp state. In particular, a solar cell film is required to have a high hydrolysis resistance since it requires a service life of 20 years or more outdoors.

  For example, Patent Document 1 describes a method for producing a polyester containing an alkali metal or alkaline earth metal phosphate.

  However, the initial COOH end group can be suppressed only with the metal phosphate, but it is difficult to suppress the increase in the COOH end group due to hydrolysis, and applications that require long-term durability, such as solar cell applications However, sufficient hydrolysis resistance cannot be obtained.

  Patent Document 2 describes a method for producing a polyester containing an inorganic phosphate, and is used in combination with phosphoric acid in Examples.

  However, since the ratio of phosphoric acid and inorganic phosphate and the amount applied are inappropriate, inorganic phosphate is easily converted into a foreign substance and has excellent short-term hydrolysis resistance, but it is necessary for solar cell applications. The hydrolysis resistance over a long period of time is insufficient, and the mechanical properties of the film are deteriorated due to foreign matters.

  Patent Document 3 describes polyethylene terephthalate containing buffered phosphorus, and is used in combination with a phosphorus compound in the examples.

However, since the optimization of the type, ratio, and application amount of the phosphorus compound is insufficient, hydrolysis resistance and mechanical properties are insufficient for solar cell applications.
In addition, as a method for producing polyester, a polycondensation reaction is performed through an esterification reaction using a dicarboxylic acid as a main raw material (a direct polymerization method), and a polycondensation reaction is performed through a transesterification reaction using a dicarboxylic acid ester as a main raw material There is a method (DMT method). The DMT method has good dispersibility of particle components and is excellent in terms of suppressing foreign matter, but has a problem that costs such as raw material costs are higher than the direct weight method. On the other hand, in the direct weight method, it is possible to carry out the esterification reaction without a catalyst, and since the raw material is inexpensive, it is very excellent in terms of cost. Since the amount is higher than that of the DMT method, the hydrolysis resistance is lowered, and the metal phosphate is easily converted into a foreign substance.

  Furthermore, as a film for solar cells, in order to impart UV resistance, matte feeling and the like, a general method is to melt and knead inorganic and organic particles to the obtained polyester composition using a twin screw extruder or the like. However, the polyester composition is thermally decomposed during hydrolysis and kneading of the polyester due to moisture brought in adsorbed on the inorganic and organic particles, resulting in a high amount of COOH end groups and high resistance. There was a problem that it was inferior in hydrolyzability.

JP 2001-144881 A JP 2007-277548 A JP 2008-7750 A

  The object of the present invention is to solve the above-mentioned conventional problems, and is a method for producing a polyester composition suitable for use as a film for solar cells, which is inexpensive, has little foreign matter, and has excellent hydrolysis resistance, UV resistance and mat feeling. Is to provide.

That is, an object of the present invention is to provide a method for producing a polyester in which a dicarboxylic acid component and a diol component are esterified and then subjected to a polycondensation reaction and a solid phase polymerization reaction, between the end of the esterification reaction and the start of the polycondensation reaction. And a diol component is added, and a diol solution of an alkali metal phosphate and inorganic particles are added to the esterification reaction product.

According to the polyester production method of the present invention, it is possible to reduce the amount of foreign matter and COOH end groups of the polyester composition, and at a low cost, the polyester composition is excellent in UV resistance, mat feeling, and hydrolysis resistance. Can be provided.

The present invention is described in detail below.

  The polyester composition production method of the present invention is a polyester production method in which a dicarboxylic acid component and a diol component are esterified and then subjected to a polycondensation reaction and a solid-phase polymerization reaction. In the meantime, it is necessary to add a diol component and add a diol solution of alkali metal phosphate and inorganic particles to the esterification reaction product.

  As the dicarboxylic acid component in the present invention, various dicarboxylic acid components such as aromatic dicarboxylic acid, chain aliphatic dicarboxylic acid, and alicyclic dicarboxylic acid can be used. Among these, aromatic dicarboxylic acids are preferred from the viewpoints of mechanical properties, heat resistance, and heat and humidity resistance of the polyester composition. In particular, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid are preferable from the viewpoint of polymerizability and mechanical properties.

Various diols can be used as the diol component in the present invention. For example, aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentylglycol, and alicyclic diols Is cyclohexanedimethanol, cyclohexanediethanol, decahydronaphthalene diethanol, decahydronaphthalene diethanol, norbornane dimethanol, norbornane dimethanol, tricyclodecane dimethanol, tricyclodecane ethanol, tetracyclododecane dimethanol, tetracyclododecane diethanol, decalin di Saturated alicyclic primary diols such as methanol and decalin diethanol, 2,6-dihydroxy-9-oxabicyclo [3,3,1] nonane, 3,9-bis 2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane (spiroglycol), 5-methylol-5-ethyl-2- (1,1-dimethyl) 2-hydroxyethyl) -1,3-dioxane, saturated heterocyclic primary diols containing cyclic ethers such as isosorbide, other cyclohexanediols, bicyclohexyl-4,4′-diols, 2,2-bis (4-hydroxys) (Cyclohexylpropane), 2,2-bis (4- (2-hydroxyethoxy) cyclohexyl) propane, cyclopentanediol, 3-methyl-1,2-cyclopentadiol, 4-cyclopentene-1,3-diol, adamantyldiol Various alicyclic diols such as bisphenol A, bisphenol S, styrene grease Lumpur, 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene, 9,9'-bis (4-hydroxyphenyl) aromatic diols such as fluorene can be exemplified. In addition to diols, polyfunctional alcohols such as trimethylolpropane and pentaerythritol can also be used.
Among these, a diol having a boiling point of 230 ° C. or lower is preferable because it is easily distilled out of the reaction system, and an aliphatic diol is more preferable because of low cost and high reactivity. Furthermore, ethylene glycol is particularly preferable from the viewpoint of mechanical properties.

  In general, when performing an esterification reaction from a dicarboxylic acid component and a diol component, the method of storing the esterification reaction product in advance and adding the slurry of the dicarboxylic acid and diol to start the esterification reaction is It is selected from the viewpoints of improving the handleability of a hardly soluble dicarboxylic acid, shortening the reaction time, and suppressing diethylene glycol by-product which can cause heat resistance. Even if the esterification reaction product is not stored, the esterification reaction proceeds, but diethylene glycol is easily produced as a by-product, and a pressurization facility and a catalyst may be required. Also in the present invention, it is preferable to carry out the esterification reaction using the stored esterification reaction product.

  In the method for producing a polyester composition in the present invention, when an esterification reaction product is obtained from the dicarboxylic acid component and the diol component, from the viewpoint of esterification reactivity and heat resistance, the dicarboxylic acid component and diol component before the start of the esterification reaction The molar ratio (diol component / dicarboxylic acid component molar ratio) is preferably in the range of 1.05 to 1.40. More preferably, it is 1.10 or more and 1.30 or less, More preferably, it is 1.15 or more and 1.20 or less. If the molar ratio is less than 1.05, since the esterification reaction does not proceed efficiently, the time cycle may be long. On the other hand, when the molar ratio exceeds 1.40, the heat resistance may be lowered by a dimer (diethylene glycol or the like) of a diol component by-produced.

  In the esterification reaction in the present invention, an alkali metal salt, a titanium compound, an ammonium salt or the like may be used as a catalyst. However, thermal decomposition or generation of foreign matters may occur in the polycondensation reaction stage. Therefore, the esterification reaction is preferably carried out without a catalyst. Even in the absence of a catalyst, the esterification reaction proceeds sufficiently by autocatalysis by the COOH end group of the dicarboxylic acid component.

  In the present invention, it is necessary to add a diol component one or more times to the esterification reaction product after the esterification reaction. By adding a diol component to the esterification reaction product, it is possible to reduce the amount of COOH end groups of the esterification reaction product, and finally reduce the amount of COOH end groups of the polyester composition after the polycondensation reaction, Improves hydrolysis resistance.

  The addition of the diol component needs to be performed after the esterification reaction is completed and before the start of the polycondensation reaction. Specifically, in the esterification reaction using a dicarboxylic acid component and a diol component, it is preferable to add it after the esterification reaction rate reaches 90% or more until the intrinsic viscosity reaches 0.3. . When the diol is added at an esterification reaction rate of less than 90%, the dimer of the diol component produced as a by-product increases and the heat resistance decreases. Furthermore, since unreacted terephthalic acid remains, the amount of COOH end groups increases and hydrolysis resistance decreases. Further, when a diol component is added during the polycondensation reaction, it does not efficiently react with the COOH end groups of the esterification reaction product, and the effect of reducing the amount of COOH end groups of the finally obtained polyester composition is reduced. .

  Furthermore, the diol component may be added in several divided portions. By adding the diol component in a plurality of times, the amount of COOH end groups of the esterification reaction product can be efficiently reduced, and the time cycle extended by the addition can be minimized. Furthermore, the dimer content of the diol component can be reduced to 1.3% by weight or less by minimizing the extension of the time cycle.

  Specifically, when the diol component is added, the lower limit of the temperature in the reaction system is preferably 210 ° C. or higher, and more preferably 220 ° C. or higher. The upper limit of the reaction system temperature is preferably 260 ° C. or less, more preferably 250 ° C. or less. When the temperature in the reaction system exceeds 260 ° C., the added diol component evaporates vigorously, and the diol component is dehydrated and condensed by the acid catalysis of the COOH end group, resulting in by-production of a dimer, which may reduce heat resistance. is there. Moreover, if it is less than 210 degreeC, the inside of a reaction system will be cooled with the added diol component, and there are concerns about the stirring trouble and delay of a time cycle by solidification of an esterification reaction product.

  The lower limit of the total amount of the diol component to be added is preferably 0.05 times mol or more, more preferably 0.10 times mol or more, further preferably 0.15 times mol or more with respect to the total dicarboxylic acid component. . Moreover, it is preferable that an upper limit is 0.65 times mole or less, More preferably, it is 0.50 times mole or less, More preferably, it is 0.35 times mole or less. When the total amount of the diol component is less than 0.05 times mol, the COOH end groups of the esterification reaction product may not be sufficiently reacted with the diol component, so the esterification reaction product and the resulting polyester composition COOH The amount of terminal groups may increase and hydrolysis resistance may decrease. Moreover, even if addition exceeding 0.65 mol is carried out, the amount of COOH end groups of the esterification reaction product does not decrease, and it takes a long time to add, so that production efficiency decreases, and the dimer of the diol component is a secondary component. And heat resistance may be reduced.

  Also, after adding the diol component, the COOH end group of the esterification reaction product and the unreacted diol component are distilled out of the reaction system, shortening the time cycle, suppressing dimer by-product of the diol component, heat resistance From the point of view, it is preferable. By distilling off the unreacted diol component to the outside of the reaction system, the temperature is quickly restored, so that the dimer content of the diol component can be reduced to 1.3% by weight or less. If the unreacted diol component is not distilled off, it takes a long time to return to the temperature, the dimer by-product of the diol component proceeds, and the heat resistance may decrease.

  In the method for producing a polyester composition of the present invention, when an additional diol component is added between the end of the esterification reaction and the start of the polycondensation reaction, the esterification reaction is performed before or simultaneously with the addition of the diol component. It is preferable to add a metal compound having activity, more preferably a metal salt, and still more preferably an acetic acid metal salt. In order to reduce the amount of COOH end groups efficiently, the lower limit of the addition amount is preferably 1.0 mol / t or more, more preferably 2.0 mol / t or more as the concentration with respect to the obtained polyester composition 1t. . Moreover, it is preferable that the upper limit of addition amount is 3.5 mol / t or less from the point of hydrolysis resistance, More preferably, it is 3.0 mol / t or less. By adding the metal salt before the diol component or simultaneously with the diol component, the reactivity between the COOH end group of the esterification reaction product and the diol component is improved, and the COOH end group can be efficiently reduced. If the concentration of the metal salt is less than 1.0 mol / t with respect to the polyester composition 1t obtained, the reaction activity is insufficient, so the amount of COOH end groups cannot be reduced, and the reaction activity is low. If the time is extended, the time cycle is extended, and eventually a polyester composition having a high COOH end group may be formed. On the other hand, if it exceeds 3.5 mol / t, the hydrolysis rate and thermal decomposition rate of the polyester composition are increased, the amount of COOH end groups is increased, and the hydrolysis resistance is lowered, which is not preferable.

  Examples of the metal salt in the present invention include metal chloride metal salt, metal acetate metal salt, metal carbonate salt, etc. Among them, metal acetate such as sodium acetate, calcium acetate, magnesium acetate, manganese acetate, cobalt acetate, zinc acetate and tin acetate. Salts are preferred. Furthermore, calcium acetate, magnesium acetate, and manganese acetate are preferable from the viewpoint of reactivity between the COOH end group of the esterification reaction product and the diol component and hydrolysis resistance.

  In the method for producing a polyester composition of the present invention, it is necessary to add a diol solution of an alkali metal phosphate after the additional addition of the diol component and before the start of the polycondensation reaction.

  Specifically, it is preferable to add as a diol solution of an alkali metal phosphate to an esterification reaction product of 220 ° C. or more and 240 ° C. or less as a concentration of 0.1 wt% or more and 5 wt% or less. Under such conditions, by adding an alkali metal phosphate, the amount of COOH end groups of the resulting polyester composition can be 20 eq / t or less, and the alkali metal phosphate has a high temperature and a high concentration. Under the conditions of addition, it is possible to prevent polyphosphoric acid from becoming a foreign substance and to impart high hydrolysis resistance. The concentration of the alkali metal phosphate diol solution is more preferably 0.2% by weight or more and 4% by weight or less, and still more preferably 0.3% by weight, from the viewpoint of suppressing the formation of foreign substances of the alkali metal phosphate. Above 3% by weight. When the amount is less than 0.1% by weight, the amount of the diol component added increases, the dimer of the diol component increases, and the heat resistance decreases. On the other hand, if it exceeds 5% by weight, it is not preferable because it is added in a high concentration state, so that the alkali metal phosphate becomes polyphosphoric acid and becomes a foreign substance. Further, the temperature at which the alkali metal phosphate diol solution is added is more preferably 220 ° C. or higher and 235 ° C. or lower, and still more preferably 220 ° C. or higher and 230 ° C., from the viewpoint of suppressing the formation of the foreign metal salt of the alkali metal phosphate. It is below ℃. If it exceeds 240 ° C., the alkali metal phosphate is likely to become a foreign substance, and if it is less than 220 ° C., the temperature decreases and the time cycle becomes longer, the amount of COOH end groups of the polyester composition obtained is undesirably high.

  The alkali metal phosphate in the present invention is not particularly limited, but sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, Examples include lithium dihydrogen phosphate, dilithium hydrogen phosphate, and trilithium phosphate. Among these, sodium dihydrogen phosphate and potassium dihydrogen phosphate are preferable from the viewpoint of hydrolysis resistance.

  The lower limit of the addition amount of the alkali metal phosphate is preferably 0.1 mol / t or more, more preferably 0.4 mol / t or more, as a concentration with respect to the polyester composition 1t obtained from the point of hydrolysis resistance. More preferably, it is 1.0 mol / t or more. In addition, the upper limit of the amount added is preferably 7.0 mol / t or less, more preferably 4.0 mol / t or less, and still more preferably 2.0 mol / t or less, from the viewpoint of foreign matter suppression and hydrolysis resistance. If it is less than 0.1 mol / t, sufficient hydrolysis resistance may not be obtained. On the other hand, if it exceeds 7.0 mol / t, the hydrolysis rate of the polyester composition is increased, the hydrolysis resistance is lowered, and the alkali metal phosphate may be made foreign.

  As a method for adding a diol solution of an alkali metal phosphate, it is preferable from the viewpoint of hydrolysis resistance that it is previously mixed with a phosphorus compound and added. At this time, it is preferable to mix the phosphorus compound in an amount of 0.1-fold mol to 7.5-fold mol with respect to the alkali metal phosphate, more preferably 0.3-fold mol to 5.0-fold mol, more preferably Is 1.0 times mol or more and 2.0 times mol or less. It is possible to control the reaction activity at the time of hydrolysis of the resulting polyester composition by mixing the phosphorus compound with 0.1 to 7.5 times moles with respect to the alkali metal phosphate. Hydrolysis resistance can be obtained. If it is less than 0.1-fold mol, hydrolysis resistance may decrease. If it exceeds 7.5-fold mol, the polymerization catalyst is deactivated by an excessive phosphorus compound, the polymerization reaction is delayed, and the COOH end groups increase. Therefore, hydrolysis resistance may decrease. In addition, if the alkali metal phosphate and the phosphorus compound are not mixed in advance and added separately, the hydrolysis resistance may decrease.

  In addition, in order to provide UV resistance and matte feeling when a solar cell film is used, inorganic particles are added to the esterification reaction product between the end of the esterification reaction and the start of the polycondensation reaction, and the polycondensation reaction is performed. After that, it is necessary to carry out a solid phase polymerization reaction.

  As a method for adding inorganic particles after the polycondensation reaction or after the solid phase polymerization reaction, it is generally practiced to melt and knead the polyester composition with a twin-screw extruder, but the adsorbed moisture adsorbed on the inorganic particles Thus, the polyester composition is hydrolyzed and the carboxyl end groups are increased, and the polyester composition is once melted and kneaded at a high temperature, so that the polyester composition is thermally decomposed and the intrinsic viscosity is decreased. This is not preferable because the carboxyl end group becomes high.

Between the end of the esterification reaction and the start of the polycondensation reaction, inorganic particles are added to the esterification reaction product, a polycondensation reaction is performed, and then a solid phase polymerization reaction is performed. In the initial stage of the polycondensation reaction, it is discharged out of the reaction system under conditions of high temperature and high vacuum, and then the polycondensation reaction and solid phase polymerization reaction are carried out. When the carboxyl terminal group of the obtained polyester composition is reduced to form a solar cell film, it becomes possible to have good hydrolysis resistance.
Examples of the inorganic particles include silicon dioxide particles, titanium oxide particles, and barium sulfate particles from the viewpoints of UV resistance, mat feeling, and availability.

  The average particle size of the inorganic particles of the present invention is preferably from 0.1 μm to 5 μm, more preferably from 0.3 μm to 3 μm. When the thickness exceeds 5 μm, unevenness on the film surface to be obtained becomes too large, resulting in coarse protrusions on the film surface or poor wear resistance. Moreover, since the filtration pressure increases in the melt filtration step of the polyester composition before film formation, it is not preferable. When the thickness is 0.3 μm or more and 3 μm or less, the balance between the matte feeling and the unevenness of the film surface is good, which is preferable. On the other hand, if it is less than 0.1 μm, the particles are agglomerated by the surface activity of the inorganic particles at the stage of the polycondensation reaction in the polyester production process, the particle dispersibility is inferior, the polymer melt viscosity increases rapidly, and the high molecular weight There is a tendency that the polymer is not obtained and the matte feeling is insufficient.

Further, BET specific surface area of the inorganic particles is preferably 10 m ² / g or more 500m ² / g or less. A preferred specific surface area is 100 m ² / g or more and 400 m ² / g or less from the viewpoint of particle dispersibility in polyester, film matt feeling, and abrasion resistance. When the specific surface area is less than 10 m ² / g, the mat feeling is inferior, and even when it exceeds 500 m ² / g, the amount of adsorbed water increases and the hydrolysis resistance deteriorates, which is not preferable.
The oil absorption amount of the inorganic particles is preferably 10 ml / 100 g or more and 400 ml / 100 g or less, more preferably 50 ml / 100 g or more and 350 ml / 100 g or less. If the oil absorption exceeds 400 ml / 100 g, the amount of adsorbed water increases and hydrolysis resistance deteriorates as described above, and even if the oil absorption is less than 10 ml / 100 g, the mat feeling is also inferior, It is not preferable.

  The added amount of the inorganic particles is 0.1% by weight or more and 10% by weight or less, more preferably 0.5% by weight or more and 5% by weight or less, and further preferably 1% by weight or more and 3% by weight, based on the polyester resin composition. It is as follows. If it is less than 0.1% by weight, the scattered light may be insufficient and a sufficient matte feeling may not be obtained. On the other hand, if it exceeds 10% by weight, it is difficult to uniformly disperse during the polycondensation reaction, and the filtration pressure of the filter may suddenly increase during film formation, which is not preferable.

  Examples of the silicon dioxide particles include white carbon, silica sol, and silica / alumina composite particles. From the viewpoint of mat feeling, aggregated silica particles are preferable.

  Examples of the method for producing the agglomerated silica particles include a wet method and a dry method. Specific wet methods include a method of decomposing sodium silicate with an acid, a method of decomposing sodium silicate with an ammonium salt or an alkali salt, and sodium silicate. Examples include a method in which an alkaline earth metal silicic acid is generated and then decomposed with an acid to form silicic acid. Specific dry methods include a dry method, a thermal decomposition method of silicon halide, a thermal decomposition method of a silicate compound, and organic silicon. Examples include a thermal decomposition method of a compound.

In order to produce a matte feeling when a solar cell film is used, a wet method is preferred in which agglomerated silica particles having a large particle size and a high oil absorption and specific surface area can be easily produced. As for the matte feeling, there is an advantage that scratches and the like are hardly visible when a solar cell film is used.
Examples of the method for producing the agglomerated silica particles by a wet method include a production method in which sodium silicate and sulfuric acid are reacted, and a sol-gel reaction is performed to produce a silica hydrogel, followed by washing with water, drying, and then pulverizing. It is done.
Moreover, it is preferable that the agglomerated silica particles are dispersed in advance and added to the esterification reaction product. As for the method of dispersion treatment, for example, using agglomerated silica as an ethylene glycol solution, performing a dispersion treatment for about 1 hour to 3 hours in advance with a high-speed stirring device such as a jet agitator of about 500 rpm to 1000 rpm. Can be mentioned.

  Examples of the titanium oxide particles include crystal-type titanium oxides such as anatase-type titanium oxide and rutile-type titanium oxide. From the viewpoint of increasing the difference in refractive index from the polyester used, titanium oxide having a refractive index of 2.7 or more is preferable, and for example, rutile titanium oxide is preferably used. Furthermore, it is particularly preferable to use high-purity titanium oxide having high purity among titanium oxides. Here, the high-purity titanium oxide means a titanium oxide having a small light absorption ability with respect to visible light, that is, a low content of coloring elements such as vanadium, iron, niobium, copper, and manganese. Examples of high-purity titanium oxide include those produced by a chlorine process. In the chlorine process, rutile ore mainly composed of titanium oxide is reacted with chlorine gas in a high-temperature furnace at about 1000 ° C. to first generate titanium tetrachloride. Subsequently, high purity titanium oxide can be obtained by burning this titanium tetrachloride with oxygen. In addition, although there is a sulfuric acid process as an industrial manufacturing method of titanium oxide, since titanium oxide obtained by this method contains a large amount of colored elements such as vanadium, iron, copper, manganese, niobium, etc., visible light Increases the light absorption capacity for. Therefore, it is difficult to obtain high-purity titanium oxide by the sulfuric acid method process.

  Further, the titanium oxide (high-purity titanium oxide) used in the present embodiment is coated with at least one inert inorganic oxide selected from silica, alumina, and zirconia on the surface. This is preferable because UV resistance is enhanced, the photocatalytic activity of titanium oxide is suppressed, and the high light reflectivity of titanium oxide is not impaired. Further, those coated with two or three kinds of inert inorganic oxides are more preferred, and among them, a combination of a plurality of inert inorganic oxides essentially including silica is particularly preferred.

  In addition, in order to improve the dispersibility of the inorganic particles in the resin, the surface of the fine powder filler is subjected to a surface treatment with a silicon compound, a polyhydric alcohol compound, an amine compound, a fatty acid, a fatty acid ester, or the like. It is also good to use.

  As the surface treatment agent, for example, at least one inorganic compound selected from a siloxane compound, a silane coupling agent, and the like on the surface of titanium oxide can be used, and these can also be used in combination. Furthermore, at least one organic compound selected from the group consisting of a siloxane compound, a silane coupling agent, a polyol, and polyethylene glycol can be used. Moreover, you may use combining these inorganic compounds and organic compounds.

  In addition, before mix | blending a rutile type titanium dioxide with a polyester composition, it is preferable to perform a particle size adjustment and coarse particle removal using a refinement | purification process. As industrial means of the purification process, for example, a jet mill or a ball mill can be applied as a pulverizing means, and as a classification means, for example, dry or wet centrifugation can be applied. In addition, you may refine | purify these means combining 2 or more types in steps.

The barium sulfate particles may be plate-shaped or spherical. Examples of the production method include pulverized barite and precipitated barium sulfate synthesized from a soluble salt and highly purified. Precipitated barium sulfate is barium chloride and sulfuric acid, barium chloride and mirabilite, barium carbonate is dissolved in hydrochloric acid and sulfuric acid is added to it, barite is dissolved in concentrated sulfuric acid and diluted with water, and barium sulfate is precipitated. A reaction of barium sulfide obtained by reduction roasting of stone and mirabilite is mentioned. From the viewpoint of mat feeling, it has high purity and high whiteness, and therefore can be suitably used as a film for solar cells.
For inorganic particles, it is preferable to use titanium oxide and barium sulfate excellent in UV resistance and silicon dioxide excellent in providing a matte feeling.

  In the method for producing a polyester composition of the present invention, it is preferable to add a trifunctional or higher functional copolymer component until the polycondensation reaction is started. Examples of the tri- or higher functional copolymer component include trimellitic acid, cyclohexanetricarboxylic acid, biphenyltetracarboxylic acid, pyromellitic acid, butanetetracarboxylic acid, and trimer acid obtained by trimerizing long-chain aliphatic carboxylic acid. Polyhydric carboxylic acids and their anhydrides and esters, glycerin, pentaerythritol, dipentaerythritol, trimethylolpropane, ditrimethylolpropane, trihydroxybenzenecarboxylic acid, trihydroxyhexanecarboxylic acid, dihydroxybenzene citrate, Examples thereof include polyvalent hydroxycarboxylic acids such as dihydroxynaphthalenecarboxylic acid and anhydrides and esters thereof. In particular, from the viewpoint of film formability, a trifunctional copolymer component is preferable.

  The trifunctional or higher functional copolymer component is preferably added until the polycondensation reaction is started, specifically until the intrinsic viscosity reaches 0.3. Since the low molecular weight polyester having an intrinsic viscosity of less than 0.3 has a low viscosity, a trifunctional or higher functional copolymer component can be uniformly reacted. Further, from the viewpoint of effectively preventing a local reaction from proceeding and causing coarse foreign matters, it is preferable that the addition interval with other additives is 5 minutes or more.

  The lower limit of the amount of the tri- or higher functional copolymer component added is preferably 0.01 mol% or more, more preferably 0. 0% with respect to the total acid component obtained from the point of hydrolysis resistance after film formation. 05 mol% or more. Further, the upper limit of the addition amount is preferably 1.00 mol% or less, more preferably 0.50 mol% or less from the viewpoint of gelation suppression. When the addition amount of the tri- or higher functional copolymer component is within the above preferable range, a sufficient hydrolysis resistance can be obtained, the progress of gelation can be prevented, and the moldability can be kept good.

  As a method for adding a trifunctional or higher functional copolymer component, it is preferable to add an ethylene glycol solution of 0.5% by mass or more and 5% by mass or less from the viewpoint of reactivity and foreign matter suppression. By adding it as an ethylene glycol solution in the above range, a tri- or higher functional copolymer component and a polyester low monomer can be reacted uniformly. When the concentration of the tri- or higher functional copolymer component in the ethylene glycol solution is within the above preferred range, the amount of ethylene glycol added to the system is not excessive, the amount of diethylene glycol as a by-product does not increase, and heat resistance In addition, while hydrolysis resistance is maintained, local reactions are unlikely to occur, and coarse foreign matters are hardly generated.

  In the manufacturing method of the polyester composition of this invention, it is preferable to implement at 285 degrees C or less at the time of a polycondensation reaction. More preferably, it is 280 degrees C or less. A temperature exceeding 285 ° C. is not preferable because the carboxyl end group becomes high.

  In the method for producing a polyester composition of the present invention, it is necessary to carry out solid state polymerization of the polyester obtained by melt polymerization in a chip shape under reduced pressure or in an inert gas flow atmosphere. For example, after preliminarily crystallizing at a temperature of 180 ° C. or lower in advance, solid state polymerization is performed at a reduced pressure of about 1 torr at 200 ° C. or higher and 240 ° C. or lower for 10 hours to 30 hours to obtain a chip having an intrinsic viscosity of about 0.8. obtain. In the case of solid phase polymerization, the solid phase polymerization temperature and precrystallization conditions may be important in satisfying both the increase in intrinsic viscosity and the reduction of carboxyl end groups at the same time. Solid-phase polymerization can be obtained by heating under appropriate conditions under reduced pressure or normal pressure, or under the flow of nitrogen gas. Polymerization is preferred.

  The polyester composition of the present invention can be molded into a polyester film. The polyester film may be an unstretched sheet or may be a stretched film stretched uniaxially or biaxially.

  Moreover, the manufacturing method is not specifically limited, For example, the following manufacturing methods can be mentioned.

  That is, after drying the polyester composition, it is melt-extruded to form an unstretched sheet, and then biaxially stretched and heat-treated to form a film. Biaxial stretching may be either longitudinal, transverse sequential stretching or simultaneous biaxial stretching, and the stretching ratio is usually 2 to 5 times each in the longitudinal and lateral directions. Further, after biaxial stretching, the film may be re-stretched in either the longitudinal or transverse direction. At this time, the polyester composition of the present invention and various polyesters may be mixed, and the polyester may be the same as or different from the catalyst or additive of the polyester of the present invention. The polyester film of the present invention may be a single layer or a laminated structure of two or more layers.

  The polyester film of the present invention can be obtained by the above-described method and can be used for various purposes. However, since the polyester of the present invention has both good hydrolysis resistance and heat resistance characteristics, It can be suitably used for a polyester film for batteries. That is, it is used as a member of a solar cell panel after being formed into a film, a sheet shape or other shapes. Since solar cells are installed outdoors, they are susceptible to hydrolysis due to water vapor and heat input and degradation due to ultraviolet rays. Since the polyester composition of the present invention has excellent heat resistance and hydrolysis resistance, it is suitably used for solar cell members.

Next, although the specific example of the polyester composition manufacturing method in this invention is given, it is not limited to this.
To the esterification reactor charged with bishydroxyethyl terephthalate dissolved at 255 ° C, a slurry of terephthalic acid and ethylene glycol (1.15 moles relative to terephthalic acid) was gradually added with a snake pump to perform esterification. Allow the reaction to proceed. The temperature in the reaction system is controlled to be 245 ° C. or more and 255 ° C. or less, and the esterification reaction is completed when the reaction rate reaches 95%.

  To the thus obtained 255 ° C. esterification reaction product, 0.27 times moles of ethylene glycol and manganese acetate with respect to terephthalic acid are simultaneously added. At this time, the temperature in the system is preferably 210 ° C. or higher and 250 ° C. or lower so that the esterification reaction product does not solidify. While distilling unreacted ethylene glycol, a sodium dihydrogen phosphate / phosphoric acid / ethylene glycol mixed solution is added at a temperature in the system of 220 ° C. to 240 ° C. Sodium dihydrogen phosphate is preferably added as a diol solution having a concentration of 0.1 wt% or more and 5 wt% or less.

Thereafter, inorganic particles are added, and while the temperature in the polymerization apparatus is gradually raised to 280 ° C., the pressure in the polymerization apparatus is gradually reduced from normal pressure to 133 Pa or less to distill ethylene glycol. At this time, when it is desired to lower the amount of COOH end groups of the polyester composition, the polymerization temperature may be set low. The reaction is terminated when a predetermined stirring torque is reached, the inside of the reaction system is brought to atmospheric pressure with nitrogen, discharged into cold water in a strand shape, and cut to obtain a pellet-shaped polyester composition.
Thereafter, the pelletized polyester composition thus obtained is pre-crystallized at a temperature of 180 ° C. or lower, and then subjected to solid state polymerization at 200 to 240 ° C. under a reduced pressure of about 1 torr for 10 to 30 hours. Thus, a polyester composition suitable for a solar cell film having a high intrinsic viscosity and a low carboxyl end group can be obtained.

Hereinafter, the present invention will be specifically described with reference to examples.
The physical properties were measured according to the following method.

(1) Average particle size of inorganic particles The particle size distribution of inorganic particles is measured using a laser diffraction / scattering particle size distribution measuring device (LA950, manufactured by Horiba, Ltd.). Titanium oxide was added so that the light transmittance was 80 to 90% under the conditions of a measurement temperature of 25 ° C. and a circulation rate of pure water solvent of 1.2 L / min to 570 ml / min, and the integrated volume integral in the measured equivalent spherical distribution The particle diameter at a rate of 50% was taken as the average particle diameter.

(2) Oil absorption amount of inorganic particles The oil absorption amount of inert inorganic particles was measured with linseed oil in accordance with JIS K-5101-19.

(3) Specific surface area of inorganic particles The specific surface area was measured by the BET method using a high-precision fully automatic gas adsorption device (BELSORP36) manufactured by Nippon Bell Co., Ltd.

(4) Intrinsic viscosity of polyester composition (IV)
Measurement was performed at 25 ° C. using orthochlorophenol as a solvent.

(5) The amount of COOH end group of the polyester composition was measured by the method of Maurice. Literature M.D. J. et al. Mauleice, F.M. Huizinga. Anal. Chim. Acta, 22 363 (1960)).

(6) DEG (diethylene glycol) content in the polyester composition Dissolve the polyester composition using monoethanolamine as a solvent, add a 1,6-hexanediol / methanol mixed solution to the solution, cool, and add terephthalic acid to After summing and centrifuging, the supernatant was measured by gas chromatography (manufactured by Shimadzu Corporation, GC-14A).

(7) The number of minute foreign matters in the polyester composition 5 g of the polyester chip after the polycondensation reaction is observed with a magnifying glass having a magnification of 10 times to confirm the foreign matters (maximum diameter 10 to 100 μm) in the polyester composition. The confirmed polyester chip is dissolved with hexafluoroisopropanol, and only the foreign matters are taken out. The energy dispersive X-ray analyzer attached to the SEM (EDX: Horiba, Ltd., EMAX-7000 type) shows phosphorus and alkali metal peaks. The number of foreign substances derived from the alkali metal phosphate detected was counted.

(8) Evaluation of hydrolysis resistance of polyester composition (ΔCOOH)
The pellet-shaped polyester composition was heat-treated at 155 ° C. and 100% RH for 4 hours, and the difference in the COOH end group amount before and after the treatment (COOH end group amount after treatment−COOH end group amount before treatment) was compared. When the difference (ΔCOOH) in the amount of COOH end groups at this time was 20 eq / t or less, it was judged to have good hydrolysis resistance.
In addition, the following heat processing apparatus was used for the processing apparatus. PRESSER COOKER 306SIII (manufactured by HIRAYAMA MFG. Co., Ltd.).

(9) Glossiness of polyester film (mat feeling)
According to JIS Z84741, the 60-degree specular gloss was measured, and the gloss of the film was measured. 70% or less was regarded as an acceptable level.

(10) Using an iSuper UW tester, a UV resistance acceleration tester for a polyester film, the following cycle was repeated 5 times to obtain an increase in the color tone b value. 7 or less was regarded as an acceptable level.
1 cycle: UV irradiation for 8 hours in an atmosphere at a temperature of 60 ° C. and a humidity of 50% RH, followed by 4 hours of aging UV irradiation intensity in a condensation state (temperature of 35 ° C., humidity of 100 RH): 100 mW / cm ² .

(11) Hydrolysis resistance of polyester film (elongation retention after standing for 60 hours under conditions of 125 ° C. and 100% humidity)
The elongation at break was measured according to ASTM-D882 (1999). The sample was cut into a size of 1 cm × 20 cm, and the elongation at break was measured when the sample was pulled at a distance of 5 cm between chucks and at a pulling speed of 300 mm / min. In addition, the measurement was performed on 5 samples, and the elongation at break was defined as the average value.
In addition, the elongation retention rate was measured at 125 ° C. and humidity 100% (pressure was about 100%) with an advanced acceleration life test apparatus EHS-221MD manufactured by Espec Corp. after cutting the sample into the shape of a measurement piece (1 cm × 20 cm). After processing for 48 hours under a condition of 1.5 atm), when the tensile elongation at break of the sample after the processing was pulled at a chucking distance of 5 cm and a pulling speed of 300 mm / min based on ASTM-D882 (1999) The elongation at break was measured. In addition, the measurement was implemented about 5 samples and the average value was made into break elongation A1.
Elongation retention (%) = A1 / A0 × 100 (1)
Using the obtained breaking elongations A0 and A1, the elongation retention was calculated by the following formula (1). Moreover, 50% or more was regarded as an acceptable level.

Example 1
In an esterification reactor preliminarily charged with 105 parts by weight of bishydroxyethyl terephthalate (equivalent to 100 parts by weight of PET), a slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol while maintaining the system temperature at 255 ° C. A glycol / terephthalic acid molar ratio of 1.15) was supplied by a snake pump, and the esterification reaction was advanced to distill water. When the esterification reaction rate reached 95%, 105 parts by weight of the resulting esterification reaction product (equivalent to 100 parts by weight of PET) was charged into a polymerization apparatus equipped with a distillation apparatus, and 0.06 part by weight of manganese acetate (2 .4 mol / t equivalent) and 0.03 part by weight of antimony trioxide (equivalent to 1.0 mol / t) were added at the same time. Thereafter, 8.7 parts by weight of ethylene glycol (0.27% relative to terephthalic acid in 100 parts by weight of PET) was added. Double moles) was added. A product obtained by diluting 0.027 part by weight of sodium dihydrogen phosphate dihydrate (equivalent to 1.7 mol / t) to a concentration of 0.35% by weight with ethylene glycol when the temperature of the esterification reaction product is 230 ° C. In addition, 0.02 part by weight of phosphoric acid (equivalent to 2.0 mol / t) was added. Thereafter, aggregated silica particles having an average particle diameter of 3.5 μm, a specific surface area of 370 m ² / g, and an oil absorption of 220 ml / 100 g were added at 2% by weight to the polyester.

Thereafter, while the temperature in the polymerization apparatus is raised to 280 ° C. over 90 minutes, the pressure in the polymerization apparatus is gradually reduced from normal pressure to 133 Pa or less to distill ethylene glycol, and when the target melt viscosity is reached, The reaction is terminated, the inside of the reaction system is brought to atmospheric pressure with nitrogen, the molten polymer is discharged from the lower part of the polymerization apparatus into cold water in the form of strands, the discharged and solidified polyester strands are cut, and the pellet-shaped polyester composition is prepared. Obtained. Intrinsic viscosity was 0.54 dl / g, carboxyl end group 19 equivalents / polyester 10 ⁶ g, DEG 1.0% by weight, fine foreign matter 0 pieces / 5 g. The polyester composition chip was subjected to solid phase polymerization at 230 ° C. for 12 hours under a reduced pressure of 50 Pa using a rotary vacuum polymerization apparatus, and a polyester having an intrinsic viscosity of 0.80, carboxyl end groups of 10 equivalents / polyester of 10 ⁶ g. A composition was obtained.

  Next, an unoriented film of 1.2 mm was obtained with a 40 mm melt extruder at a set temperature of 280 ° C. and a residence time of 6 minutes. Under normal conditions, this was biaxially stretched 3.2 times in the machine direction and 4.1 times in the transverse direction to obtain a 75 micron biaxially oriented polyester film. The polyester film has 55% gloss, UV resistance (Δb) 5, hydrolysis resistance MD80%, TD70% and good glossiness (matte feeling), UV resistance, hydrolysis resistance. It was. The results are shown in Tables 1, 2, and 3.

Example 2
The procedure of Example 1 was repeated except that the additional amount of diol was 0.27 mol twice, for a total of 0.54 mol. Although DEG was slightly higher, it had good gloss, UV resistance, and hydrolysis resistance. The results are shown in Tables 1, 2, and 3.

Example 3
The procedure was the same as Example 1 except that the additional amount of diol was 0.05 mol. Although the amount of COOH end groups was slightly higher, the glossiness, UV resistance, and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 4
The procedure was the same as Example 1 except that the amount of sodium dihydrogen phosphate added was 6.0 mol / t. Since the amount of sodium dihydrogen phosphate added was large, 1/5 g of fine foreign matter was generated, but the glossiness, UV resistance, and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 5
Example 1 was repeated except that the amount of sodium dihydrogen phosphate added was 0.3 mol / t. Although the amount of sodium dihydrogen phosphate added was small, the amount of carboxyl end groups was slightly high, but the glossiness, UV resistance, and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 6
The procedure was the same as Example 1 except that phosphoric acid was not added. Some foreign matter due to sodium dihydrogen phosphate was generated and the hydrolysis resistance was inferior, but it was at a usable level. The results are shown in Tables 1, 2, and 3.

Example 7
Example 1 was repeated except that the concentration of sodium dihydrogen phosphate diol solution was 5% by weight. Since the concentration of addition was high, 3 / 5g of fine foreign matters were generated, but the glossiness, UV resistance, and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 8
Example 1 was repeated except that the concentration of the diol solution of sodium dihydrogen phosphate was 0.1% by weight. Although the concentration of addition was low, the amount of diol added increased and DEG slightly increased, but it had good gloss, UV resistance, and hydrolysis resistance. The results are shown in Tables 1, 2, and 3.

Example 9
The same procedure as in Example 1 was performed except that the temperature at the time of adding the diol solution of sodium dihydrogen phosphate was 240 ° C. Since the addition temperature was high, 3/5 g of foreign matters were generated, but the glossiness, UV resistance, and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 10
Example 1 was repeated except that the temperature at the time of adding the diol solution of sodium dihydrogen phosphate was 250 ° C. Since the addition temperature is higher than Example 8, 8 / 5g of fine foreign matters are generated, and since the temperature is high, the amount of carboxyl end groups is slightly increased, and the hydrolysis resistance of the obtained polyester film is Although it deteriorated, it was of a usable level. Moreover, the glossiness and UV resistance were maintained by the effect of the addition of the agglomerated silica. The results are shown in Tables 1, 2, and 3.

Example 11
Example 1 was repeated except that the temperature at the time of adding the diol solution of sodium dihydrogen phosphate was 220 ° C. Since the addition temperature was low, it took time until the temperature returned, and although 1/5 g of fine foreign matter was generated, it had good glossiness, UV resistance, and hydrolysis resistance. The results are shown in Tables 1, 2, and 3.

Example 12
Example 1 was repeated except that the amount of manganese acetate added was 3.5 mol / t. Although the thermal decomposition was slightly promoted and the amount of carboxyl end groups was slightly increased, the glossiness, UV resistance, and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 13
Example 1 was repeated except that the amount of manganese acetate added was 1.0 mol / t. Although the reaction of the carboxyl end group of the diol added and the esterification reaction product was suppressed and the amount of the carboxyl end group was slightly increased, the glossiness, UV resistance, and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 14
The procedure was the same as Example 1 except that the esterification reaction initiation EG molar ratio was 1.40. Although the EG molar ratio was high, DEG was slightly high, but it had good gloss, UV resistance, and hydrolysis resistance. The results are shown in Tables 1, 2, and 3.

Example 15
The same procedure as in Example 1 was conducted except that the esterification reaction initiation EG molar ratio was 1.05. Since the EG molar ratio was low, the esterification reaction was prolonged and DEG was slightly higher, but it had good glossiness, UV resistance, and hydrolysis resistance. The results are shown in Tables 1, 2, and 3.

Example 16
The procedure was the same as Example 1 except that the type of alkali metal phosphate was changed to potassium dihydrogen phosphate. Although the carboxyl end group amount was slightly higher, the glossiness, UV resistance, and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 17
The procedure was the same as Example 1 except that the type of phosphorus compound was changed to TEPA (triethylphosphonoacetate). Although the carboxyl end group amount was slightly higher, the glossiness, UV resistance, and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 18
Example 1 was repeated except that the metal salt was changed to magnesium acetate. Although the carboxyl end group amount was slightly higher, the glossiness, UV resistance, and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 19
The same procedure as in Example 1 was conducted except that the average particle size of the aggregated silica particles was 5.0 μm. The glossiness (mat feeling) was improved, and the UV resistance and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 20
The same as Example 1 except that the average particle size of the aggregated silica particles was 0.1 μm. Although the glossiness (mat feeling) was slightly inferior, it had good UV resistance and hydrolysis resistance. The results are shown in Tables 1, 2, and 3.

Example 21
The procedure was the same as Example 1 except that the addition amount of the aggregated silica particles was 10% by weight. The glossiness (mat feeling) was improved, and the UV resistance and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 22
The procedure was the same as Example 1 except that the amount of the aggregated silica particles added was 0.1% by weight. Although the glossiness (mat feeling) was slightly inferior, it had good UV resistance and hydrolysis resistance. The results are shown in Tables 1, 2, and 3.

Example 23
The procedure was the same as Example 1 except that colloidal silica having a specific surface area of 20 m ² / g and an oil absorption of 20 ml / 100 g was used. Although the glossiness (mat feeling) was slightly inferior, it had good UV resistance and hydrolysis resistance. The results are shown in Tables 1, 2, and 3.

Example 24
The procedure was the same as Example 1 except that rutile titanium oxide was used. Although the surface activity of the particles was high, the amount of carboxyl end groups was slightly increased, but the UV resistance was improved, and the glossiness and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 25
The procedure was the same as in Example 1 except that anatase-type titanium oxide was used. Although the surface activity of the particles was high, the amount of carboxyl end groups was slightly higher, but it was slightly inferior to the rutile type titanium oxide of Example 22, but the UV resistance was improved, and the glossiness and hydrolysis resistance were good. there were. The results are shown in Tables 1, 2, and 3.

Example 26
The procedure was the same as in Example 1 except that barium sulfate was used. Although the surface activity of the particles was high, the amount of carboxyl end groups was slightly increased, but the UV resistance was improved, and the glossiness and hydrolysis resistance were good. The results are shown in Tables 1, 2, and 3.

Example 27
Example 1 was the same as Example 1 except that 2% by weight of the agglomerated silica of Example 1 and 1% by weight (total 3% by weight) of the rutile-type titanium oxide of Example 23 were added. Although the obtained polyester film was slightly inferior in hydrolysis resistance, it was highly satisfactory in both glossiness and UV resistance. The results are shown in Tables 1, 2, and 3.

Example 28
Example 2 was the same as Example 1 except that 2% by weight of the agglomerated silica of Example 1 and 3% by weight (total 5% by weight) of the rutile-type titanium oxide of Example 23 were added. The obtained polyester film was highly satisfactory in both glossiness and UV resistance, but the amount of carboxyl end groups in the polymer increased due to an increase in the amount of rutile titanium oxide having high surface activity. Also, the hydrolysis resistance of the obtained polyester film was such that the elongation retention after PCT 60 hr was as low as 50%. The results are shown in Tables 1, 2, and 3.

Example 29
The procedure was the same as Example 1, except that 2% by weight of the agglomerated silica of Example 1 and 1% by weight (total 3% by weight) of barium sulfate of Example 25 were added. Although the obtained polyester film was slightly inferior in hydrolysis resistance, it was highly satisfactory in both glossiness and UV resistance. The results are shown in Tables 1, 2 and 3. Example 30
Trimellitic anhydride was added as a tri- or higher functional copolymerization component in the same manner as in Example 1 except that 0.1 mol was added before the esterification reaction was completed and manganese acetate was added. The hydrolysis resistance was improved, and the glossiness and UV resistance were good. The results are shown in Tables 1, 2, and 3.

Comparative Example 1
The procedure was the same as in Example 1 except that inorganic particles were not added. Since inorganic particles were not added, the glossiness (mat feeling) and UV resistance were poor. The results are shown in Tables 1, 2, and 3.

Comparative Example 2
Before the polycondensation reaction, inorganic particles are not added, and the solid phase polymerized polyester composition and agglomerated silica are supplied in powder form so as to be 2% by weight from the side feeder, and a total L / D45 of 46 mmφ at 100 kg / hr. The same direction vent type biaxial kneader was used, and the kneading was performed at a screw rotation speed of 200 rpm (Ns), Q / Ns = 0.5, a resin temperature of 280 ° C., and a vacuum degree of 5 kPaA. The obtained polyester composition had an intrinsic viscosity of 0.70 dl / g and a carboxyl end group amount of 25 eq / t, and the resulting polyester film had very low hydrolysis resistance. The results are shown in Tables 1, 2, and 3.

Comparative Example 3
The procedure was the same as Example 1 except that solid phase polymerization was not performed. Since solid phase polymerization was not carried out, the amount of carboxyl end groups after the polycondensation reaction was 19 eq / t, and ΔCOOH was as high as 40 eq / t. Therefore, film formation evaluation was not performed. The results are shown in Tables 1, 2, and 3.

Comparative Example 4
The procedure was the same as Example 1 except that no additional diol was added. Since no additional addition was made, reduction of the carboxyl end group due to the reaction of the carboxyl end group after the esterification reaction and the additionally added diol could not be expected, and the amount of the carboxyl end group was 25 eq / t after the polycondensation reaction. After polymerization, it was as high as 16 eq / t, and the hydrolysis resistance of the polyester film was very low. The results are shown in Tables 1, 2, and 3.

Comparative Example 5
The same procedure as in Example 1 was conducted except that the alkali metal phosphate was directly added as a powder instead of a diol solution. Since the alkali metal phosphate is converted into a foreign substance, the polymer after polycondensation has a very large amount of fine foreign substances of 50 pieces / 5 g, and since the alkali metal phosphate is converted into a foreign substance, the function of hydrolysis resistance is not exhibited. The hydrolysis resistance of the polyester film was also very low. The results are shown in Tables 1, 2, and 3.

Claims (6)

In a polyester production method in which a dicarboxylic acid component and a diol component are esterified, followed by a polycondensation reaction and a solid-phase polymerization reaction, an additional diol component is added between the end of the esterification reaction and the start of the polycondensation reaction. A method for producing a polyester composition, comprising adding an alkali metal phosphate diol solution and inorganic particles to an esterification reaction product. The polyester composition according to claim 1, wherein a diol solution of alkali metal phosphate is added to an esterification reaction product at a temperature of 220 to 240 ° C at a concentration of 0.1 to 5% by weight. Method. The polyester composition according to claim 1 or 2, wherein the alkali metal phosphate to be added is 0.1 mol / t or more and 7.0 mol / t or less with respect to the polyester composition 1t to be obtained. Method. The method for producing a polyester composition according to any one of claims 1 to 3, wherein the diol component added after the esterification reaction is 0.05 to 0.65 mol relative to the dicarboxylic acid component. The method for producing a polyester composition according to any one of claims 1 to 4, wherein the inorganic particles are at least one selected from the group consisting of silicon dioxide particles, titanium dioxide particles, and barium sulfate particles. . The method for producing a polyester composition according to any one of claims 1 to 5, wherein a tri- or higher functional copolymer component is added before the start of the polycondensation reaction.