JP2011052190A - Method for producing polyester and film using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently producing a polyester having a low refractive index and excellent thermal stability, and to provide a film which is obtained by using the polyester produced by the method and has a low photoelastic coefficient and excellent light reflection properties. <P>SOLUTION: The method for producing a polyester is provided in which a polyester is produced by performing a transesterification reaction of a dicarboxylic acid component containing an alicyclic dicarboxylic acid and a diol component and then performing a polycondensation reaction. In the method, the transesterification reaction is performed in the presence of an alkali metal compound (A), and after the transesterification reaction, an alicyclic diol, a phosphorus compound (B), and a titanium compound (C) are added in succession, and then the polycondensation reaction is performed, wherein, the glass transition temperature measured by differential scanning calorimetry is 65-90°C, the refractive index with sodium D-line is 1,500-1,570, the gelation rate is ≤10%, the content of metal element of the (A) is 5-200 ppm, the content of metal element of the (B) is 10-300 ppm, and the content of metal element of the (C) is 3-100 ppm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is a method for producing a polyester excellent in production stability and thermal stability of an alicyclic component-containing polyester. Specifically, in the polyester production reaction process, by adding the alicyclic diol after the transesterification reaction, and by determining the additive, the amount of catalyst, and the order of addition, the decomposition of the alicyclic diol is suppressed, and the production stability And a method for producing polyester excellent in thermal stability. Further, the polyester can provide an optical polyester film excellent in optical isotropy and light reflectivity.

Polyester containing an alicyclic component has optical characteristics, crystallization characteristics, and mechanical characteristics different from aromatic polyesters such as polyethylene terephthalate (hereinafter referred to as PET). The polyester alone or the aromatic polyester Used in combination.

  For industrial use, for example, a film in which polymers having different refractive indexes are alternately laminated can efficiently reflect light having a specific wavelength, and thus is used as an optical filter or a reflector. A film having excellent optical isotropy is used as a retardation film in a liquid crystal display or the like.

  For example, in Patent Document 1, a light-reflective film in which a copolymerized polyester is laminated on polyethylene naphthalate resin (hereinafter PEN), and in Patent Document 2, a light-reflective fiber in which nylon or acrylic is laminated on a polyester resin is disclosed in Patent Document 2. No. 3 proposes a multilayer optical film obtained by laminating PEN and a copolymer polyester, and JP-A No. 2004-259542 proposes a photographic film made of a PEN copolymer polyester excellent in transparency.

  However, the polyesters described in Patent Documents 1 and 3 are inferior in workability because polyesters having different glass transition temperatures are laminated, and the polymer combination in Patent Document 2 is laminated because the adhesion between polymers is inferior. It is not suitable for diverting to a film, and polyesters described in Patent Documents 1, 3, and 4 have a large photoelastic coefficient and cannot be used for liquid crystal displays and the like.

  Patent Document 5 describes a method for producing a polyester by copolymerizing a dicarboxylic acid and / or diol having a cyclic acetal skeleton. For example, glass can be obtained by copolymerizing spiroglycol having a rigid molecular chain. Although it is disclosed that the transition point temperature is increased and the crystallinity is decreased, if the polyester is used in a multilayer laminated film with PET, the Tg is higher than that of PET, and therefore, when the film is formed, the unevenness of lamination is disclosed. Inferior generation and workability are expected. In addition, the refractive index cannot be lowered sufficiently, and the reflectance is expected to be low when a multilayer laminated film is formed.

  In Patent Documents 6 to 8, an ester having a specific acid value or less is obtained by an esterification reaction and a polycondensation reaction of a dicarboxylic acid and a diol, and a spiroglycol having a cyclic acetal skeleton is added to the ester to perform a polycondensation reaction. Suppresses the degradation of the cyclic acetal by the carboxyl group of dicarboxylic acid and water, suppresses a marked increase in gelation and molecular weight distribution, and industrially advantageous production method. It is disclosed that a polyester having excellent mechanical properties can be obtained. However, the reaction process requires a long reaction time, and spiroglycol having a cyclic acetal skeleton is decomposed by residual acid groups and moisture, so that the crosslinking reaction is accelerated and the production stability cannot be obtained. Polyester is not fully satisfactory in thermal stability.

  Patent Documents 9 to 11 disclose a method for producing a polyester containing an alicyclic dicarboxylic acid and an alicyclic diol in order to obtain a polyester having a refractive index lower than that of PET while maintaining a glass transition temperature equivalent to that of PET. Has been. However, in Patent Document 9, a phosphoric compound, an alkali metal, and then spiroglycol, which is an alicyclic diol, are added to an ester having a specific acid value by an esterification reaction of a dicarboxylic acid and an aliphatic diol, and the esterification reaction is continued. By adding a condensation reaction catalyst and performing a polycondensation reaction, it is said that the decomposition of spiroglycol is suppressed and the polyester having excellent thermal stability is economically produced. The decomposition of glycol could not be sufficiently suppressed, and the production stability and thermal stability tended to be inferior.

  Patent Documents 10 and 11 disclose a production method in which all polyester raw materials are charged and a polycondensation reaction is performed from a transesterification reaction. However, the transesterification reaction is not sufficiently performed, spiroglycol tends to be scattered out of the reaction system during the polycondensation reaction, the production stability of the polyester tends to be poor, and the thermal stability tends to be poor. .

JP 2000-141567 A WO98 / 46815 pamphlet Japanese National Patent Publication No. 9-506837 JP-A-6-295014 JP 2004-67829 A JP 2004-137477 A JP-A-2005-314643 JP 2006-225621 A JP 2008-308641 A JP 2008-63417 A JP 2009-1656 A

  The object of the present invention is to solve the above-mentioned conventional problems, and is a method for producing a polyester excellent in production stability and thermal stability of an alicyclic component-containing polyester, having a low photoelastic coefficient, and further comprising a laminated film and It is an object of the present invention to provide a polyester exhibiting excellent reflectivity and a polyester film using the same.

  The object of the present invention described above is to provide a polyester satisfying the following characteristics (1) to (3) by subjecting a dicarboxylic acid component containing an alicyclic dicarboxylic acid and a diol component to an ester exchange reaction and then a polycondensation reaction. In the production, the ester exchange reaction is performed in the presence of the alkali metal compound (A), and the alicyclic diol, the phosphorus compound (B), and the titanium compound (C) are sequentially added after the ester exchange reaction, and then the polycondensation reaction. It can be achieved by a polyester production method characterized by

Glass transition temperature by differential scanning calorimetry: 65 to 90 ° C. (1)
Refractive index at sodium D line: 1.500 to 1.570 (2)
Gelation rate: 10% or less (3)
(The gelation rate is the ratio of the amount of ortho-chlorophenol insoluble matter after the polyester is heat-treated at 280 ° C. for 2.5 hours under an oxygen concentration of 1%.)
Metal element content of (A): 5 to 200 ppm (vs. polyester)
Metal element content of (B): 10 to 300 ppm (vs. polyester)
(C) Metal element amount: 3 to 100 ppm (vs. polyester)
Moreover, the characteristic of light reflectance 90% or more is achieved by the laminated polyester film which laminates | stacks the polyester obtained by the manufacturing method of polyester of this invention alternately, and PET.

  According to the present invention, when an alicyclic diol is copolymerized, the presence of an alkali metal compound (A) is obtained by combining a dicarboxylic acid alkyl ester component containing an alicyclic dicarboxylic acid alkyl ester and a diol component not containing an alicyclic diol. By performing the transesterification reaction below, the reaction of the dicarboxylic acid component is sufficiently carried out, and at the same time, there is no residual acid group or moisture, and in this reaction step, an alicyclic diol is added to an alkaline low polymer. The decomposition of the cyclic diol can be suppressed, and then the phosphorus compound (B) and the titanium compound (C) are added in this order, and then the conditions for the polycondensation reaction are adopted to further decompose the alicyclic diol. It is possible to produce a polyester excellent in production stability and thermal stability.

  Moreover, the polyester obtained by this invention has a low photoelastic coefficient suitable for a liquid crystal display, and can obtain the laminated polyester film excellent in light reflectivity.

  The polyester production method of the present invention is a polyester satisfying the following characteristics (1) to (3) by transesterification of a dicarboxylic acid component containing an alicyclic dicarboxylic acid and a diol component, followed by a polycondensation reaction. In the presence of an alkali metal compound (A), an alicyclic diol, a phosphorus compound (B), and a titanium compound (C) are sequentially added after the transesterification, followed by polycondensation. It is a manufacturing method of polyester characterized by reacting.

Glass transition temperature by differential scanning calorimetry: 65 to 90 ° C. (1)
Refractive index at sodium D line: 1.500 to 1.570 (2)
Gelation rate: 10% or less (3)
(The gelation rate is the ratio of the amount of ortho-chlorophenol insoluble matter after the polyester is heat-treated at 280 ° C. for 2.5 hours under an oxygen concentration of 1%.)
Metal element content of (A): 5 to 200 ppm (vs. polyester)
Metal element content of (B): 10 to 300 ppm (vs. polyester)
(C) Metal element amount: 3 to 100 ppm (vs. polyester)
The polyester obtained by the method for producing a polyester of the present invention contains at least an alicyclic dicarboxylic acid and an alicyclic diol, has a glass transition temperature (hereinafter referred to as Tg) in the range of 65 to 90 ° C, and It is necessary that the refractive index at the sodium D line has a range of 1.500 to 1.570.

  When the Tg is less than 65 ° C., the optical properties of the polyester or its molded product are likely to change with time due to insufficient thermal stability, and there is a difference in Tg between laminated resins when laminated with PET or the like. Since it becomes large, lamination | stacking nonuniformity etc. generate | occur | produce and film forming stability is impaired. On the other hand, when the Tg exceeds 90 ° C., the Tg difference becomes too large when laminating with PET or the like as described above, so that laminating unevenness occurs, film formation stability is impaired, and the refraction of the polyester film It becomes difficult to lower the rate. Furthermore, if the Tg difference becomes large when laminated with PET, the adhesion with PET tends to be poor and delamination tends to occur.

  In the case of a laminated film, the Tg of the polyester of the present invention is preferably matched with the Tg of the laminated polymer, and the difference between the Tg (Tg1) of the laminated polymer and the Tg (Tg2) of the polyester of the present invention (| Tg1−Tg2 |) Is preferably within 10 ° C, more preferably within 5 ° C. Therefore, the Tg of the polyester of the present invention is preferably in the range of 70 to 87 ° C, more preferably in the range of 75 to 85 ° C.

  Regarding the refractive index of the polyester of the present invention, it is difficult for the polyester resin to make the refractive index less than 1.500, and when it exceeds 1.570, the difference in refractive index from the laminated polymer becomes small. The light reflectance of the laminated film thus obtained is reduced. The refractive index of the polyester of the present invention is preferably in the range of 1.510 to 1.560. In addition, the refractive index in this invention points out the refractive index measured using the sodium D line | wire on 23 degreeC conditions.

  In order to obtain the properties described above, the polyester of the present invention needs to contain at least an alicyclic dicarboxylic acid in the dicarboxylic acid structural unit and an alicyclic diol in the diol structural unit. The aromatic ring contained in the polyester has the effect of increasing the Tg of the polyester, but at the same time has the effect of increasing the refractive index and increasing the photoelastic coefficient. When the photoelastic coefficient is large, the phase difference changes greatly when a stress is applied to the film, so that it is not suitable for a film for use in a liquid crystal display.

  Therefore, the polyester of the present invention is obtained by substituting a part of an aromatic dicarboxylic acid as a dicarboxylic acid component with a part of an alicyclic dicarboxylic acid or a part of ethylene glycol as a diol component. The photoelastic coefficient can be reduced.

  In the present invention, since it is necessary to carry out a transesterification (hereinafter referred to as EI) reaction, an alicyclic dicarboxylic acid alkyl ester of an alicyclic dicarboxylic acid is used. Examples of the alicyclic dicarboxylic acid alkyl ester include dimethyl cyclohexane dicarboxylate and dimethyl decalin dicarboxylate. In particular, dimethyl cyclohexanedicarboxylate is preferable from the viewpoint of availability and reactivity. In addition, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid alkyl ester include cis- and trans-isomers as stereoisomers. In the present invention, the trans-isomer ratio is preferably 40% or less. If the transformer ratio is high, the photoelastic coefficient tends to increase. In addition, since the trans isomer has a higher melting point than the cis isomer, the reactivity tends to be inferior when the trans isomer ratio increases. Furthermore, it easily coagulates and settles during storage at room temperature or during transportation, resulting in poor workability in handling. Therefore, the trans isomer ratio is preferably 35% or less, and more preferably 30% or less.

  As the alicyclic diol in the present invention, spiroglycol and isosorbide are preferable, and spiroglycol is particularly preferable from the viewpoint of the color tone of the obtained polyester. Here, spiroglycol refers to 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane.

  In the present invention, for example, in the case of PET, Tg decreases when terephthalic acid (aromatic ring component) is substituted with cyclohexanedicarboxylic acid or the like. On the other hand, Tg rises by substituting ethylene glycol with alicyclic diols such as spiroglycol, and as a result, the polyester of the present invention can be adjusted to a Tg comparable to that of normal PET used for laminated films.

  In the polyester of the present invention, the number of moles of aromatic rings contained in 1 kg of polyester is preferably 4.8 moles or less in order to reduce the refractive index and the photoelastic coefficient. When it exceeds 4.8 mol, the refractive index and the photoelastic coefficient tend to increase, which is not preferable. The number of moles of aromatic rings in the present invention is based on the number of moles of benzene rings. The definition in the present invention will be described using PET and PEN as examples.

  In the case of PET, since the molecular weight of the basic repeating unit is 192, the number of basic repeating units per 1 kg of polyester is 5.2. Since 1 mol of terephthalic acid (corresponding to one benzene ring) is contained in the basic repeating unit, the number of moles of aromatic ring of PET is calculated to be 5.2. On the other hand, in the case of PEN, the molecular weight of the basic repeating unit is 242 and the number of basic repeating units per kg of polyester is 4.1. Although 1 mole of naphthalene dicarboxylic acid component is contained in the basic repeating unit, since the naphthalene ring corresponds to 2 benzene rings, the number of moles of aromatic ring of PEN is calculated as 8.2 moles.

  The polyester of the present invention contains at least an alicyclic dicarboxylic acid and an alicyclic diol, and the other dicarboxylic acid component is at least one selected from dimethyl terephthalate, dimethyl 2,6-naphthalenedicarboxylate, and dimethyl isophthalate. It is preferable to add 20-95 mol% of dimethyl dicarboxylate with respect to the total dicarboxylic acid component. Moreover, about a diol component, it is preferable to add 20-95 mol% of ethylene glycol as a diol component. When the aromatic dicarboxylic acid is less than 20 mol%, it is difficult to make Tg 65 ° C. or higher. For example, when laminating with PET or PEN, the interlayer adhesion with these polyesters tends to deteriorate. . Similarly, when ethylene glycol is less than 20 mol%, interlayer adhesion with these polyesters deteriorates when laminated with PET or PEN. On the other hand, when the aromatic dicarboxylic acid exceeds 95 mol%, it is difficult to reduce the refractive index and the photoelastic coefficient, and when ethylene glycol exceeds 95 mol%, it is difficult to increase the Tg to 65 ° C. or higher. .

  Therefore, in the polyester of the present invention, the addition amount of the alicyclic dicarboxylic acid and the alicyclic diol is preferably in the range of 5 to 80 mol%, more preferably 8 to 50 mol% from the above description.

  The polyester of the present invention is preferably amorphous, and is substantially amorphous within the above-mentioned copolymerization range. The term “amorphous” in the present invention means that the heat of crystal fusion is 4 J / g or less as measured by a differential scanning calorimeter (DSC). Such an amorphous polyester is preferable because its optical properties hardly change during film production.

  Since the polyester obtained by the production method of the present invention is amorphous, it tends to be heat-sealed by drying and easily form a lump. Then, the lump formation by drying can be suppressed by including 5 to 50 weight% of crystalline polyester in the polyester of this invention. As such a crystalline polyester, it is preferable that the heat of crystal fusion in differential scanning calorimetry is 4 J / g or more.

  As a method of including the crystalline polyester, melt kneading by a vent type extruder is preferable. That is, it is a method of obtaining pellets by melting and kneading the crystalline polyester and the polyester of the present invention with a vent type extruder. Examples of the crystalline polyester include PET, polybutylene terephthalate, PEN, and copolymers thereof, and among them, PET is most preferable.

  The aromatic dicarboxylic acid contained in the polyester of the present invention is at least selected from the above-mentioned types, but dimethyl terephthalate and dimethyl isophthalate are preferable from the viewpoint of refractive index and photoelastic coefficient, and these are used simultaneously. It doesn't matter. In particular, dimethyl terephthalate is preferably used mainly from the viewpoints of adhesiveness with other polyesters. In addition, as the dicarboxylic acid component, a conventionally known component may be copolymerized as long as the characteristics allow. The same applies to the diol component. Examples of such components include aliphatic dicarboxylic acid alkyl esters such as adipic acid and sebacic acid, and aromatic dicarboxylic acid alkyl esters such as 4,4′-bisphenylenedicarboxylic acid, 5-sodium sulfoisophthalic acid, and diphenic acid. . Moreover, diol components, such as diethylene glycol, butanediol, propanediol, polyethylene glycol, polytetramethylene glycol, can be mentioned.

Furthermore, by adding an antioxidant, decomposition of spiroglycol tends to be suppressed by suppressing oxidation in the reaction system. As the antioxidant, a phenolic antioxidant and a phosphorus antioxidant that do not adversely affect the reactivity and properties of the polyester are preferable, and the addition amount is preferably 0.5% by weight or less based on the obtained polyester. . If the added amount exceeds 0.5% by weight, problems such as rise in the liquid level due to foaming during the reaction and decomposition products may be scattered outside the system and block the reaction process circuit, etc. It is not preferable. Preferably it is 0.1 weight% or less, More preferably, it is 0.05 weight% or less. The reaction step for adding the antioxidant is preferably from before the EI reaction to immediately before the polycondensation reaction. Examples of phenolic antioxidants include pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4- Hydroxyphenyl) propionate] and the like and phosphorus antioxidants include bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite, bis (2,4-di-tert) -Butylphenyl) pentaerythritol-di-phosphite and the like can be mentioned, but the invention is not limited thereto. Further, two or more kinds of antioxidants may be used in combination.
Furthermore, inorganic particles, organic particles, dyes, pigments, antistatic agents, waxes and the like may be included.

  The polyester of the present invention needs to have a gelation rate of 10% or less, preferably 8% or less, more preferably 5% or less. The gelation rate is a ratio of the ortho-chlorophenol insoluble matter to the whole after heat treatment of the polyester under an oxygen concentration of 1% under the condition of 280 ° C. × 2.5 hr. In particular, polyesters copolymerized with spiroglycol are characterized by being decomposed and gelled by heat and oxygen.

  Therefore, when the gelation rate exceeds 10%, it means that the polyester is extremely easily gelled. For example, when it is discharged into a strand after the polycondensation reaction, the shape becomes fussy and cannot be cut with a cutter. In the filter filtration process when forming a film, the filtration pressure may increase abnormally due to a large amount of gel, the surface defect of the laminated film may increase, or the laminated thickness of the multilayer laminated film may vary. .

  In the method for producing a polyester of the present invention, an alicyclic component, particularly spiroglycol, which is an alicyclic diol, tends to promote decomposition when heated under an acid component, in an acidic state or under water, and the functional group tends to increase. It is necessary to advance the polycondensation reaction from the EI reaction because the molecular weight distribution is broadened during the reaction and the crosslinking is promoted.

  In the production of the polyester of the present invention, an EI reaction vessel is subjected to an EI reaction with a dicarboxylic acid alkyl ester component containing an alicyclic dicarboxylic acid alkyl ester which is a polyester raw material and an ethylene glycol which is a diol component not containing an alicyclic diol. When performing, it is necessary to add an alkali metal compound (A) to the said polyester raw material, and to perform EI reaction.

  Moreover, it is necessary to add spiroglycol which is alicyclic diol to the alkali metal containing low polymer after completion | finish of EI reaction. On the other hand, spiroglycol is charged at the same time as other polyester raw materials before EI reaction, and spiroglycol is decomposed by the EI reaction catalyst, which is a known acetate salt. And thermal stability is poor.

  Further, it is necessary to add the phosphorus compound (B) and sufficiently react with the EI reaction catalyst, and then add the titanium compound (C).

  Furthermore, it is necessary to react the obtained low polymer in a polycondensation reaction vessel. The polyester obtained by the production method can produce a polyester excellent in production stability such as ejection stability without being spiroglycol crosslinked, and further excellent in thermal stability.

  The alkali metal compound (A) added before the EI reaction needs to be added in an amount of 5 to 200 ppm as an alkali metal element with respect to the obtained polyester. If the amount of the alkali metal element added exceeds 200 ppm, the polycondensation reactivity is remarkably inferior, the polyester tends to become turbid, the ester bonds are decomposed, and the mechanical properties are lowered due to the decrease in molecular weight, which is not preferable. On the other hand, if it is less than 5 ppm, decomposition of spiroglycol, which is an alicyclic diol, cannot be sufficiently suppressed, and gelation due to crosslinking tends to be promoted. When the resulting polyester is molded, the formation and acceleration of the gel causes poor molding and reduced physical properties, which is not preferable. Therefore, the addition amount of the alkali metal compound (A) as an alkali metal element is preferably 5 to 150 ppm, more preferably 10 to 100 ppm.

  Although the alkali metal element used for this invention is not specifically limited, Potassium, sodium, and lithium can be mentioned, At least 1 sort (s) of alkali metal is added. As the alkali metal compound (A), hydroxide, acetate and phosphate are preferable. Sodium and lithium compounds tend to color the polyester, and phosphates tend to make the polyester slightly turbid. Of these, potassium hydroxide is preferred as the alkali metal compound (A).

  Further, in the method for producing a polyester of the present invention, the EI reaction catalyst is 30 to a polyester obtained as a metal element with at least one metal compound selected from the group consisting of alkaline earth metals, Zn, Co and Mn. It is preferable to add 300 ppm.

  In the alkaline earth metal, Mg is preferable because Ca easily forms foreign matters. Among Zn, Co, and Mn, Mn is particularly preferable from the viewpoint of foreign matter and color tone. Among these, Mg and Mn are preferable from the viewpoint of transparency of the polyester. Two or more of these metals may be used in combination.

  The above-mentioned metal compound is preferably soluble in polyester, and particularly known acetate is preferable.

  In the method for producing a polyester of the present invention, spiroglycol, which is an alicyclic diol added after completion of the EI reaction, is easily added to an alkali metal-containing low polymer because the spiroglycol is in powder form. I can't. For this reason, it can be easily added to the low polymer by using a liquid such as ethylene glycol which is a raw material of other diol components as a medium. For example, the concentration of spiroglycol / ethylene glycol is 20 to 60% by weight in consideration of fluidity and sedimentation. If it exceeds 60% by weight, it tends to be inferior in kneadability and fluidity and cannot be easily added. On the other hand, if the amount is less than 20% by weight, the spiroglycol sedimentation property becomes remarkable, which may hinder the accuracy of addition, may delay the reaction time due to a large amount of addition, and may deteriorate the properties of the resulting polyester. More preferably, it is 30 to 50% by weight. When adding with a spiroglycol / ethylene glycol slurry, the reactivity and polyester characteristics can be stabilized by adopting a step of distilling excess ethylene glycol out of the reaction system at the same time as addition or after completion of addition. .

  Furthermore, it is necessary to add 10 to 300 ppm as a phosphorus element in the phosphorus compound (B) to the polyester from which the phosphorus compound (B) can be obtained from the viewpoint of thermal stability for suppressing gelation and black foreign matters. is there. The addition amount of the phosphorus compound (B) is the sum of the phosphorus element amount in the pentavalent and trivalent phosphorus compounds. When the amount of phosphorus element exceeds 300 ppm, the polycondensation reactivity is inferior, and a remarkable effect for suppressing gelation or black foreign matter cannot be obtained, which is economically useless. On the other hand, if it is less than 10 ppm, gelation due to crosslinking tends to be promoted during the polycondensation reaction, production stability cannot be obtained, the color tone of the obtained polyester tends to deteriorate, and the cause is inferior thermal stability The polyester becomes black, and when the polyester is used as a raw material for hot melt molding, the polyester gels, which may cause clogging of the molten polymer filter and adversely affect the resulting product. There is not preferable. Therefore, the addition amount of the phosphorus element in the phosphorus compound (B) is preferably 20 to 280 ppm, more preferably 30 to 250 ppm.

  The pentavalent and trivalent phosphorus compounds described above are not particularly limited, but examples of the phosphorus compound (B) include phosphoric acid, phosphorous acid, phosphonic acid, and phosphinic acid compounds. The ester compound is preferable from the viewpoint of suppressing the formation of foreign matter.

  The pentavalent phosphorus compound is preferably one or two of phosphoric acid, phosphonic acid, phosphinic acid, and phosphine oxide. Specifically, for example, phosphates such as phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, methylphosphonic acid, ethylphosphonic acid, propylphosphonic acid, isopropylphosphonic acid, butylphosphonic acid, phenylphosphonic acid Phosphonic acids such as benzylphosphonic acid, tolylphosphonic acid, xylylphosphonic acid, biphenylphosphonic acid, naphthylphosphonic acid, anthrylphosphonic acid, diethylphosphonoacetic acid, methyl diethylphosphonoacetate, ethyl diethylphosphonoacetate, etc. Phosphinic acid such as phosphorous acid, methylphosphinic acid, ethylphosphinic acid, propylphosphinic acid, isopropylphosphinic acid, butylphosphinic acid, phenylphosphinic acid, tolylphosphinic acid, trimethylphosphine oxide, triethylphosphine oxy Phosphine oxide such as id and the like, it is preferred that these are either one or two. In particular, from the viewpoints of thermal stability and color tone improvement, phosphoric acid and / or phosphonic acid are preferable. Of these, trimethyl phosphate and ethyl diethylphosphonoacetate are preferable.

  The addition amount of the trivalent phosphorus compound is preferably 0 to 300 ppm, more preferably 0 to 200 ppm, and still more preferably 0 to 100 ppm as the amount of phosphorus element in the phosphorus compound (B).

  Examples of trivalent phosphorus compounds include phosphite compounds, phosphonite compounds, phosphinite compounds, phosphine compounds, and alkyl esters or aryl esters thereof. These trivalent phosphorus compounds are generated by side reactions. By converting the peroxide (R—O—OH: further promoting side reactions) to alcohol (R—OH) and changing itself to a pentavalent phosphorus compound, the effect as an antioxidant and the polyester It has the effect of suppressing side reactions. On the other hand, when a large amount is added, decomposition products may adhere to the reaction process circuit and the like, and the reaction may not proceed.

    Examples of the trivalent phosphorus compound include commercially available phosphites, alkyl diarylphosphites, aryl diarylphosphites, dialkyl arylphosphonites, and diaryl arylphosphonites. Are triphenyl phosphite, tris (4-monononylphenyl) phosphite, tri (monononyl / dinonyl phenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, monooctyl diphenyl phosphite Monodecyl diphenyl phosphite, bis [2,4- (bis 1,1-dimethylethyl) -6-methylphenyl] ethyl phosphite, tetrakis (2,4-di-tert-butylphenyl) 4,4′- Biphenylene diphosphite, Tris (2,4 Di-tert-butylphenyl) phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol -Di-phosphite, 3,9-bis (2,4-dicumylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane, phenyl-neopentylene glycol- Phosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite, tetra (C12-C15 alkyl) -4, 4'-isopropylidenediphenyl diphosphite and the like can be mentioned. Not intended to be.

  Following the addition of the phosphorus compound (B), it is necessary to add 3 to 100 ppm as a titanium element in the titanium compound (C) to the resulting polyester. When the addition time of the titanium compound (C) is added in the step before the phosphorus compound (B) is added, there is a possibility that the reaction activity of titanium may be lost by the phosphorus compound (B). Further, immediately after the addition of the phosphorus compound (B), the reaction between the phosphorus compound (B) and the EI reaction catalyst is not sufficiently performed, and the unreacted phosphorus compound (B) may react with the titanium compound (C). The reaction activity is lost, which is not preferable. In order not to lose the reaction activity of the titanium compound (C), the time from the completion of the addition of the phosphorus compound (B) to the addition of the titanium compound (C) is preferably about 10 to 60 minutes.

In addition, since titanium compound (C) has high low-temperature reaction activity and low acidity, spiroglycol decomposition inhibition and reactivity are improved, and spiroglycol scattered outside the reaction system is suppressed. The cross-linking of the resin is suppressed, and production stability is obtained.
If the added amount of elemental titanium exceeds 100 ppm, the crosslinking tends to be accelerated by a rapid polycondensation reaction, the color tone of the obtained polyester tends to deteriorate, and the thermal stability is inferior, and the polyester is black. It is not preferable because the polyester may be gelated when the polyester is used as a raw material and hot-melt molding is performed, and the melted polymer filter may be clogged or the obtained product may be adversely affected. On the other hand, when the concentration is less than 3 ppm, the polycondensation reaction activity cannot be sufficiently obtained, and thus the polycondensation reaction time tends to be prolonged and a polyester having a sufficiently high degree of polymerization cannot be obtained. Therefore, the amount of titanium element added is preferably 5 to 80 ppm, more preferably 8 to 50 pm.

  The above-described titanium compound (C) is not particularly limited, but the titanium compound (C) includes at least one selected from the group consisting of titanium alkoxide, polyvalent carboxylic acid, hydroxycarboxylic acid, and nitrogen-containing carboxylic acid as a chelating agent. It is preferable that it is a titanium complex.

  Examples of the titanium alkoxide include titanium compounds (C) having an alkoxy group such as tetraethoxide, tetrapropoxide, tetraisopropoxide, tetrabutoxide, tetra-2-ethylhexoxide and the like. Tetrabutoxide is particularly preferable.

  Examples of the polyvalent carboxylic acid that is a chelating agent for the titanium compound (C) include phthalic acid, trimellitic acid, trimesic acid, hemititic acid, pyromellitic acid, and the like, and hydroxycarboxylic acid includes lactic acid, malic acid, and tartaric acid. Citric acid and the like, and as nitrogen-containing carboxylic acid, ethylenediaminetetraacetic acid, nitrilotripropionic acid, carboxyiminodiacetic acid, carboxymethyliminodipropionic acid, diethylenetriaminopentaacetic acid, triethylenetetraminohexaacetic acid, iminodiacetic acid, Examples include iminodipropionic acid, hydroxyethyliminodiacetic acid, hydroxyethyliminodipropionic acid, methoxyethyliminodiacetic acid, and the like. In particular, a titanium complex using hydroxycarboxylic acid lactic acid or citric acid as a chelating agent is preferred. These titanium compounds (C) may be used alone or in combination.

  In the polyester production method of the present invention, when the EI reaction is carried out in an EI reaction vessel, the diol component not containing an alicyclic diol preferably has a molar ratio of 1.65 to 2.3 times the total dicarboxylic acid component. . Further, after completion of the EI reaction, an alicyclic diol and a catalyst are added to obtain a low polymer having a molar ratio of 1.6 to 2.2 times the total diol component to the total dicarboxylic acid component. It is preferable to proceed the polycondensation reaction by raising the temperature of the low polymer in a polycondensation reaction vessel and reducing the pressure at 60 to 180 minutes. Further, the final pressure reduction degree of the polycondensation reaction is preferably 133 Pa or less. Moreover, it is preferable to carry out the polycondensation reaction temperature as low as possible at 270 to 290 ° C. from the viewpoints of polycondensation reactivity, crosslinking inhibition, and thermal stability. The polycondensation reaction temperature is the final constant temperature because the polycondensation reaction is performed at a constant temperature after reaching a certain target temperature over a period of 60 to 150 minutes by gradually increasing the temperature from 225 to 240 ° C. It is. When the temperature is higher than 290 ° C., although the polycondensation reaction is promoted, the thermal decomposition is promoted and the polyester adhering to the gelation or the discharge nozzle hole becomes black, which is not preferable. A temperature lower than 270 ° C. is not preferable because sufficient polycondensation reaction activity cannot be obtained and the polycondensation reaction time tends to be delayed. Therefore, the polycondensation reaction temperature is preferably 270 to 288 ° C, more preferably 275 to 285 ° C.

  The polyester of the present invention thus obtained preferably has an intrinsic viscosity in the range of 0.55 to 1.0. When the intrinsic viscosity is less than 0.55, the polyester becomes brittle, which is not preferable. When the intrinsic viscosity exceeds 1.0, the melt viscosity becomes high, so that accurate lamination becomes difficult.

  The polyester film of the present invention contains the above-described polyester of the present invention, has a small photoelastic coefficient and refractive index, and can be suitably used for liquid crystal display applications.

  The laminated polyester film of the present invention exhibits excellent light reflectivity by being laminated with polyester having different refractive indexes. The laminated polyester film of the present invention is a polyester film containing at least one layer of the polyester of the present invention. In order to obtain excellent light reflectivity, the polyester of the present invention and PET are preferably laminated alternately.

  Since the polyester of the present invention has a refractive index lower than that of PET and is amorphous, the refractive index hardly changes even when the film is stretched. Therefore, light is efficiently reflected at the interface between the polyester layer and the PET layer of the present invention.

  Of course, a higher light reflectance is preferable, but 90% or more is preferable as a light reflective film. In order to obtain excellent light reflectivity, the total number of laminated layers is preferably 250 or more.

  A method for obtaining such a laminated film is realized by feeding polyester fed from different flow paths into a multilayer laminating apparatus using two or more extruders. Examples of the multilayer laminating apparatus include a multi-manifold die, a feed block, a static mixer, and the like. In particular, it is preferable to use a multi-manifold die or a feed block in view of the accuracy of the laminated thickness. The polyester laminated in this manner is extruded into a sheet form from the die and cooled by a cooling drum or the like, so that an unstretched sheet can be obtained. In order to obtain an unstretched sheet with favorable thickness unevenness and surface condition, it is preferable to employ an electrostatic application method.

  The resulting unstretched sheet can then be uniaxially or biaxially stretched. In biaxial stretching, simultaneous biaxial stretching and sequential biaxial stretching can be performed.

  Next, the manufacturing method of the polyester of this invention and the manufacturing method of a film are demonstrated in detail.

  In the method for producing the polyester of the present invention, spiroglycol, which is an alicyclic diol, tends to promote decomposition when heated under an acid component, under acidic conditions or in water, and the functional group tends to increase, and the molecular weight distribution during the reaction When the alicyclic diol is copolymerized, the dicarboxylic acid alkyl ester component containing the alicyclic dicarboxylic acid alkyl ester and the diol component not containing the alicyclic diol are combined with an alkali metal compound ( A) EI reaction under the content, and after adding an ethylene glycol slurry of spiroglycol, an alicyclic diol, to the alkali metal-containing low polymer obtained by the EI reaction, distilling excess ethylene glycol, phosphorus After adding the compound (B) and then the titanium compound (C), the polycondensation reaction is carried out from the EI reaction vessel. It goes into the container, using a method of polycondensation of low polymer in particular polycondensation reaction conditions.

  As raw materials, for example, dimethyl terephthalate, which is a dicarboxylic acid alkyl ester component, dimethyl cyclohexanedicarboxylate, and ethylene glycol, which is a diol component, are charged into an EI reaction vessel in a predetermined amount so as to become the polyester of the present invention. In this case, the amount of ethylene glycol as the diol component is such that the EI reactivity is improved when the molar ratio to the total dicarboxylic acid component is 1.65 to 2.3 times.

  To the polyester comprising the raw material, a metal compound such as manganese acetate tetrahydrate as an EI reaction catalyst and potassium hydroxide which is a hydroxide containing potassium element as an alkali metal compound (A) are added. Further, at about 150 ° C., the monomer component becomes a uniform molten liquid. Next, the EI reaction is performed while distilling methanol while gradually raising the temperature in the reaction vessel to 230 ° C. over 4 hours. In this way, an ethylene glycol slurry of spiroglycol, which is an alicyclic diol as a raw material, is added to the EI reaction vessel so that the EI reaction is completed and the polyester of the present invention is obtained (the reaction system does not become 220 ° C. or lower). (Slowly or in several batches), while distilling excess ethylene glycol, after the distillation of surplus ethylene glycol is completed, trimethyl phosphate or diethylphosphonoacetic acid is used as a deactivator for the EI reaction catalyst. A phosphorus compound (B) such as ethyl is added. Next, 30 minutes after the completion of the addition of the phosphorus compound (B), a polycondensation reaction catalyst which is a titanium compound (C) such as a citrate chelate titanium compound or tetra-n-butyl titanate is added and sufficiently stirred. Then, a low polymer having a molar ratio of all diol components to all dicarboxylic acid components of about 1.6 to 2.2 times is obtained. Next, the low polymer is transferred from the transesterification reaction vessel to a polycondensation reaction vessel at 235 ° C. Thereafter, the temperature was raised simultaneously with depressurization, the pressure from normal pressure to 133 Pa or lower was set to 90 minutes, and the temperature was raised from 235 to 285 ° C. for 90 minutes. And As the polycondensation reaction proceeds, the viscosity of the reaction product increases. Predetermined polyester viscosity is obtained by completing the polycondensation reaction using the stirring torque as a guide, and at the same time, the inside of the reaction system is brought to normal pressure with nitrogen, the stirrer is stopped, the inside of the polycondensation reaction vessel is under nitrogen pressure, and the discharge hole More gut-like polyester is discharged into the water tank. The discharged polyester is quenched in a water tank and made into chips with a cutter.

  Although the polyester of the present invention can be obtained by such a method for producing a polyester, the above is an example, and the monomer, catalyst and polycondensation reaction conditions are not limited thereto.

  Next, film formation of a polyester film will be described.

  For film formation, a good T-die method with small thickness unevenness can be preferably used.

  When the polyester obtained by the method for producing a polyester of the present invention is melt-extruded, an extruder-type melt-extrusion apparatus having a single-screw or twin-screw extruder can be used. The laminated film can be manufactured by using two or more extruders, laminating the molten polyester with a multi-manifold die or a feed block, and extruding the laminated polyester.

  The casting method is to measure the melted polyester with a gear pump and then discharge it from a T-die die, and use a static contact method such as an electrostatic application method, an air chamber method, an air knife method, or a press roll method, which is a well-known contact means on a cooled drum. It is preferable to closely cool and solidify in a cooling medium such as a drum and rapidly cool to room temperature to obtain an unstretched film. In particular, the electrostatic application method is particularly preferably used to obtain flatness and uniform thickness.

  The obtained unstretched film can be further uniaxially or biaxially stretched.

  The stretching method of biaxial stretching is not particularly limited, and methods such as a sequential biaxial stretching method and a simultaneous biaxial stretching method can be employed.

  When stretching by sequential biaxial stretching, the obtained unstretched film is contact-heated on a roll group heated to Tg-30 ° C. or more and Tg + 50 ° C. or less of polyester, and 1.1 to 4 in the longitudinal direction. The film is stretched by 0 times and once cooled, and then the end of the film is bitten by a tenter clip, and the polyester is stretched in the temperature direction at a temperature of Tg + 5 ° C. or higher and Tg + 50 ° C. or lower in the width direction. Stretched 0 times to obtain a biaxially oriented polyester film.

  When the biaxially oriented film after stretching is further heat-treated at a temperature in the range of Tg + 50 ° C. to Tg + 150 ° C., the dimensional stability is improved.

  The polyester film thus obtained has a low photoelastic coefficient and is suitable as a liquid crystal display film. Moreover, the film which laminated | stacked PET etc. alternately is excellent in light reflectivity, and is suitable for a reflector use.

  The present invention will be described more specifically with reference to the following examples.

  In addition, the measuring method of a physical property and the evaluation method of an effect were performed in accordance with the following method.

(1) Thermal properties of polyester (Tg, heat of crystal melting)
About 10 mg of the sample to be measured was weighed, sealed with an aluminum pan and pan cover, and measured with a differential scanning calorimeter (DSC7 model, manufactured by Perkin Elmer). In the measurement, the temperature was raised from 20 ° C. to 285 ° C. at a rate of 16 ° C./min in a nitrogen atmosphere, then rapidly cooled with liquid nitrogen, and again from 20 ° C. to 285 ° C. at a rate of 16 ° C./min. Raise the temperature. Tg was measured in the second temperature raising process.
The amount of heat of crystal melting was calculated from the area of the crystal melting peak appearing in the second temperature raising process.

(2) Refractive index of polyester An unstretched sheet having a thickness of 100 μm is obtained by melt-extruding polyester. Next, the refractive index was measured with an “Abbe refractometer NAR-4T” manufactured by Atago Co., Ltd. under a temperature condition of 23 ° C. using sodium D line as a light source.

(3) Intrinsic viscosity of polyester Polyester was melted in a solvent of ortho-chlorophenol (hereinafter referred to as OCP) and measured at 25 ° C.

(4) Gelling rate of polyester The polyester is freeze-pulverized to form a powder having a diameter of 300 μm or less and vacuum-dried at 50 ° C. for 2 hours. 0.5 g of this sample is put in a stainless steel vessel with a pipe lid, and the oxygen concentration is made 1% with a mixed gas of air and nitrogen. The container is immersed in an oil bath at 280 ° C. and heat-treated for 2.5 hours. This is dissolved in 50 ml OCP at a temperature of 160 ° C. for 40 minutes. Subsequently, it is filtered through a Buchner type glass filter (maximum pore size 20-30 μm), washed and vacuum dried. The weight of the OCP insoluble matter remaining on the filter was calculated from the increase in the weight of the filter before and after filtration, and the weight fraction of the OCP insoluble matter with respect to the polyester weight (0.5 g) was determined to obtain the gelation rate (%). .

(5) A cis / trans isomer ratio sample of cyclohexanedicarboxylic acid was diluted 5 to 6 times with methanol, and 0.4 μl of the diluted solution was measured by liquid chromatography under the following conditions.
Device: Shimadzu LC-10ADvp
Column: Capillary column DB-17 manufactured by Agilent Technologies (length 30 m, inner diameter 0.32 mm, film thickness 0.25 μm)
Temperature rising conditions: initial temperature 110 ° C., initial time 25 minutes, temperature rising rate 6 ° C./min, final temperature 200 ° C.
(6) Acid value of ester low polymer (i) Potency of N / 25 ethanolic sodium hydroxide solution Titrate with 0.08 g of sulfamic acid dissolved in 70 ml of pure water to determine the titer. (Ii) Acid value of ester low polymer
About 0.2 g of the ester low polymer was weighed, 50 ml of an o-cresol / chloroform (3: 2) solution was added, melted at 90 ° C. for 1 hour, and then allowed to cool for 30 minutes. Thereafter, 30 ml of chloroform was added, 5 ml of a 13% lithium chloride methanol solution was further added, and titration was performed with N / 25 ethanolic sodium hydroxide solution using COM-450 manufactured by Hiranuma. From the titration result, the acid value (μ equivalent / g) was calculated by the following formula.

Acid value (μ equivalent / g) = A × f × 10 ³ × (1/25) / w
However, A: Sample drop constant (ml)
f: titer of N / 25 ethanolic sodium hydroxide solution
w: Amount of collected ester low polymer (7) Photoelastic coefficient (× 10 ⁻¹² Pa ⁻¹ )
A sample having a short side of 1 cm and a long side of 7 cm was cut out. The thickness of this sample is d (μm). Using this sample, TRANSDUCER U3C1-5K manufactured by Shimadzu Corp., a tension of 1 kg / mm ² (9.81 × 10 ⁶ Pa) was applied in the long side direction with 1 cm between the top and bottom. . In this state, the phase difference R (nm) was measured using a polarizing microscope 5892 manufactured by Nikon Corporation. Sodium D line (589 nm) was used as a light source. These numerical values were applied to photoelastic coefficient = R / (d × F) to calculate the photoelastic coefficient.

The case where the photoelastic coefficient was less than 100 × 10 ⁻¹² Pa ⁻¹ was regarded as acceptable.

(8) Reflectance A spectrophotometer (U-3410 Spectrophotometer) manufactured by Hitachi, Ltd. was fitted with a φ60 integrating sphere 130-0632 (Hitachi Ltd.) and a 10 ° inclined spacer, and the peak value of the reflectance was measured. The band parameter was set to 2 / servo, the gain was set to 3, and the range from 187 nm to 2600 nm was set to 120 nm / min. Measured at a detection speed of. In order to standardize the reflectance, an attached BaSO ₄ plate was used as a standard reflecting plate. In this evaluation method, since the relative reflectance is obtained, the reflectance may be 100% or more.

(9) Peelability The test was conducted according to JIS K5600 (2002). The film was regarded as a hard substrate, and 25 lattice patterns were cut at intervals of 2 mm. Further, a tape cut to a length of about 75 mm was adhered to the lattice portion, and the tape was peeled off at an angle close to 60 ° in a time of 0.5 to 1.0 seconds. Here, Sekisui's cello tape (registered trademark) no. 252 (width 18 mm) was used. The evaluation result was expressed by the number of lattices in which one lattice was completely separated. When the thickness of the test film was less than 100 μm, a sample in which the test film was firmly bonded to the biaxially stretched PET film (Toray “Lumirror” T60) having a thickness of 100 μm with an adhesive was used for the peel test. . At this time, a test was performed by cutting a grid in the surface of the test sample so as not to penetrate the test sample. The number of peeling was 4 or less.
The method for synthesizing the catalyst is described below.

Reference Example 1 (Titanium Catalyst A. Synthesis Method of Citric Acid Chelate Titanium Compound)
Citric acid monohydrate (532 g, 2.52 mol) was dissolved in warm water (371 g) in a 3 L flask equipped with stirrer, condenser and thermometer. Titanium tetraisopropoxide (284 g, 1.0 mol) was slowly added to the stirred solution from the addition funnel. The mixture was heated to reflux for 1 hour to produce a cloudy solution, from which the isopropanol / water mixture was distilled and distilled under reduced pressure. The product was cooled to a temperature below 70 ° C., and 380 g of a 32 wt% aqueous solution of NaOH was slowly added via a dropping funnel while stirring the solution. The resulting product was filtered and then mixed with ethylene glycol (504 g, 8.1 mol) and heated under vacuum to remove isopropanol / water and a slightly cloudy, pale yellow product (Ti-containing) Amount 3.85% by weight).

Reference Example 2 (Titanium Catalyst B. Lactate Chelate Titanium Compound Synthesis Method)
Ethylene glycol (218 g, 3.51 mol) was added from a dropping funnel to titanium tetraisopropoxide (284 g, 1.0 mol) stirred in a 2 L flask equipped with a stirrer, condenser and thermometer. . The addition rate was adjusted so that the heat of reaction warmed the flask contents to about 50 ° C. The reaction mixture was stirred for 15 minutes and 252 g of an 85 wt% aqueous solution of ammonium lactate was added to the reaction flask to give a clear, light yellow product (Ti content 6.54 wt%).

Reference Example 3 (Titanium catalyst C. Synthesis method of titanium alkoxide compound)
Ethylene glycol (496 g, 8.0 mol) was added from a dropping funnel to titanium tetraisopropoxide (284 g, 1.0 mol) stirred in a 2 L flask equipped with a stirrer, condenser and thermometer. . The addition rate was adjusted so that the heat of reaction warmed the flask contents to about 50 ° C. To the reaction flask, 125 g of a 32 wt% aqueous solution of NaOH was slowly added by a dropping funnel to obtain a clear yellow liquid (Ti content 5.2 wt%).

Example 1
(Synthesis of polyester)
67.6 parts by weight of dimethyl terephthalate (hereinafter referred to as DMT), 17.4 parts by weight of dimethyl cyclohexanedicarboxylate (hereinafter referred to as CHDC) having a cis / trans isomer ratio of 75/25, 52.0 ethylene glycol (hereinafter referred to as EG) An EI reaction vessel was charged with parts by weight of manganese acetate tetrahydrate (content 99% or more) (hereinafter referred to as Mn acetate) 0.06 parts by weight / EG 1.5 parts by weight of EG solution and alkali As metal compound (A), potassium hydroxide (content 85% or more) (hereinafter referred to as hydroxide K) 0.005 part by weight / EG 0.5 part by weight of EG solution was added, and the contents were dissolved at 150 ° C. The mixture was stirred (the molar ratio of the diol component including the catalyst and the additive ethylene glycol to the total dicarboxylic acid component was 2.0 times). While stirring, methanol (hereinafter referred to as MA) was distilled while slowly raising the temperature of the reaction contents to 230 ° C. over 4 hours. A predetermined amount of MA was distilled off, and the EI reaction was terminated to obtain an alkali metal-containing low polymer. Thereafter, SPG / EG slurry comprising 19.9 parts by weight / EG 24.3 parts by weight of spiroglycol (hereinafter referred to as SPG) was gradually added to the low polymer and added in three portions (reaction system temperature). Was added so as not to be 220 ° C. or lower). Further, excess EG distilled off at the same time as the addition was driven out of the reaction system, and when the temperature in the EI can reached 230 ° C., as the phosphorus compound (B), ethyl diethylphosphonoacetate (content 97% or more) ( Hereinafter, an EG solution containing 0.05 parts by weight of TEPA / 1.0 parts by weight of EG was added. After adding TEPA, excess EG was distilled off with stirring for 30 minutes. Then, after adding 20 ppm (EG solution) of titanium catalyst A as a titanium element as a titanium compound (C), excess EG was distilled for 10 minutes while stirring, and the total diol component was 2% relative to the total dicarboxylic acid component. A low polymer of 0.05 mol times was obtained.

  In addition, except the titanium catalysts A, B, and C of the titanium compound (C), each metal element of the catalyst and the additive compound in the examples in the table is a value converted to 100% purity.

  Thereafter, the low polymer was transferred to a polycondensation reaction vessel.

  Subsequently, the polycondensation reaction vessel was stirred and the pressure was reduced and the temperature was increased, and a polycondensation reaction was performed while distilling EG. The pressure reduction rate was reduced from normal pressure to 133 Pa or less over 90 minutes, and the temperature increase rate was raised from 235 ° C. to 285 ° C. over 90 minutes. There was no vacuum failure due to clogging of the decompression circuit during the polycondensation reaction, the polycondensation reaction time was 212 minutes, the stirring torque reached a predetermined value, the polycondensation reaction vessel was returned to normal pressure with nitrogen gas, and stirring was performed. The blade was stopped, the valve at the bottom of the polycondensation reaction vessel was opened, gut-like polyester was discharged into the water tank, and then chipped. In addition, the deposit adhering to the pressure reduction circuit of a polycondensation reaction container was not observed. In addition, no poor ejection properties were observed. Furthermore, the intrinsic viscosity was 0.68, Tg was 78 ° C., the heat of crystal fusion was 4 J / g or less (not observed: nd), and the gelation rate was 2%.

(Synthesis of PET)
In an EI reaction vessel, 100 parts by weight of DMT and 61 parts by weight of EG are charged into an EI reaction vessel. As an EI reaction catalyst, 0.06 parts by weight of magnesium acetate (hereinafter referred to as Mg acetate) /1.5 parts by weight of EG, and a polycondensation catalyst EG slurry of 0.03 part by weight of antimony trioxide (Sb trioxide) /1.5 parts by weight of EG was added, and the contents were dissolved at 150 ° C. and stirred (the diol component including the catalyst and the additive ethylene glycol was The molar ratio to the total dicarboxylic acid component is 2.0 times). While stirring, MA was distilled while slowly raising the temperature of the reaction contents to 230 ° C. over 4 hours. A predetermined amount of MA was distilled off to complete the EI reaction. Then, trimethyl phosphate (content 99% or more) (hereinafter TMPA) 0.02 parts by weight / EG 1.0 parts by weight EG solution was added, and the excess EG distilled at the same time as the addition was distilled while stirring for 30 minutes To obtain a low polymer.

  Subsequently, the low polymer was transferred to a polycondensation reactor, and polycondensation reaction and discharge were performed to obtain PET having an intrinsic viscosity of 0.65 and Tg of 80 ° C.

(Formation of single-layer biaxially stretched film)
Although the polyester chip was vacuum-dried, a lump was seen in a part thereof, which was broken and then supplied to the extruder. The polyester supplied to the extruder was melted at 280 ° C., filtered through a metal nonwoven fabric filter, and then extruded from a T die as a molten sheet. The molten sheet was cooled and solidified on a mirror drum whose surface temperature was controlled at 25 ° C. by an electrostatic application method (electrode used was a tungsten wire having a diameter of 0.15 mm) to obtain an unstretched sheet. The unstretched sheet had a refractive index of 1.552 and a photoelastic coefficient of 86 × 10 ⁻¹² Pa ⁻¹ .

(Formation of laminated polyester film)
The polyester and PET were each vacuum dried and then fed to two extruders.

  Polyester and PET were each melted at 280 ° C. by an extruder, passed through a gear pump and a filter, and then joined by a 101-layer feed block. At this time, both surface layers of the laminated film were made to be PET resin layers, and the laminated thickness was laminated alternately so that the polyester layer / PET resin layer was ½. The polyester layers were alternately laminated so that 50 layers and 51 PET layers were formed.

    The 101-layer laminate thus obtained was supplied to a die, extruded into a sheet, and rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. by electrostatic application (DC voltage 8 kV). .

  The obtained cast film was led to a roll type longitudinal stretching machine, heated by a group of rolls heated to 90 ° C., and stretched three times in the longitudinal direction between rolls having different peripheral speeds. The film that had been stretched in the machine direction was then led to a tenter-type transverse stretcher. The film was preheated with hot air at 100 ° C. in a tenter and stretched 3.3 times in the transverse direction. The stretched film was directly heat treated with hot air at 200 ° C. in a tenter. In this way, a film having a thickness of 50 μm could be obtained. The laminated film had no problem in peelability and was excellent in light reflectance of 100%. Properties of the obtained polyester and film are shown in Tables 1 to 4.

Examples 2-5
Similar to Example 1, except that the amount ratio of DMT, CHDC, EG, SPG in Example 1 was changed and the amount of alkali metal compound (A), phosphorus compound (B), and titanium compound (C) were changed. Polyester and film were obtained. In Examples 2 and 3, the Tg was different from that of PET by about 10 ° C., and thus some unevenness occurred when biaxially stretching, but the level was not a problem. In Example 4, since the number of moles of aromatic rings was large, there was no problem in slightly increasing the photoelastic coefficient. In Example 5, since the number of moles of the aromatic ring was small, the refractive index was lowered and excellent light reflectivity was exhibited.

Examples 6 and 7
Example 6 was performed except that SPG of Example 1 was changed to isosorbide (hereinafter referred to as ISB), and CHDC of Example 1 was changed to dimethyl decalin dicarboxylate (hereinafter referred to as DDCM), and further the quantitative ratio was changed. A polyester and a film were obtained in the same manner as in Example 1. The reactivity, polyester characteristics, and film characteristics satisfied the characteristics of the present invention.

Example 8
A polyester and a film were obtained in the same manner as in Example 1 except that CHDC having a cis / trans ratio of CHDC of Example 1 of 60/40 was used. Since the transformer ratio of CHDC was higher than in Example 1, the photoelastic coefficient was higher but good.

Examples 9-13
Polyester and film in the same manner as in Example 1 except that the types and addition amounts of the alkali metal compound (A), phosphorus compound (B), and titanium compound (C) in Example 1 were changed, and a phenolic antioxidant was used in combination. Got. That is, in Example 9, the titanium compound (C) was changed to tetra-n-butyl titanate (content: 99% or more) (manufactured by Nippon Soda Co., Ltd.) (hereinafter, TBT), and Example 11 was a phosphorus compound (B ) Is changed to TMPA, and at the same time, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol di-phosphite (content: 99% or more), a trivalent phosphorus compound (Asahi Denka Kogyo) "Adeka Stub PEP36" (hereinafter, PEP36) manufactured by the same company was added simultaneously. Example 12 is pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (“CIGANOX 1010” manufactured by Ciba Japan Co., Ltd.), which is a phenolic antioxidant. (Hereinafter referred to as IR1010) was added simultaneously with the EI catalyst, and the titanium compound (C) was changed to the titanium catalyst B. In Example 13, the alkali metal compound (A) was changed to sodium hydroxide (content: 93% or more) (hereinafter, Na hydroxide) and the titanium compound (C) was changed to the titanium catalyst C. Characteristics and the like are shown in Tables 1 to 4.

Example 14
A polyester and a film were obtained in the same manner as in Example 1 except that the addition amount and polycondensation temperature of the phosphorus compound (B) and titanium compound (C) titanium catalyst A in Example 11 were changed. Since the polycondensation temperature was lowered, the polycondensation reaction time was slightly longer, but it was at a satisfactory level.

Examples 15 and 16
A polyester and a film were obtained in the same manner as in Example 1 except that the intrinsic viscosity of Example 1 was changed. All were good levels.

Example 17
Example 1 Polyester with changed amounts of CHDC and SPG: 75 parts by weight and PET: 25 parts by weight are mixed and kneaded by a vented twin-screw extruder having an L / D of 42. A film was obtained in the same manner as in 1. The polyester chip did not form a mass due to heat fusion even during vacuum drying, and the film formation was stable.

Example 18
A film was obtained in the same manner as in Example 1 except that the total number of layers 101 in Example 1 was changed to 251 in the total number of layers. The thickness of the obtained laminated polyester film was 50 μm, and showed excellent light reflectivity by increasing the number of laminated layers.

Comparative Example 1
A polyester and a film were obtained in the same manner as in Example 1 except that the SPG addition time of Example 1 was added prior to the EI reaction simultaneously with other raw materials DMT, CHDC, and EG. At the end of the polycondensation decompression cam, a temperature abnormality in the decompression circuit and a slight decompression failure occurred. When the decompression circuit of the polycondensation reaction vessel was disassembled, droplet deposits on the circuit were observed. Moreover, the gelation rate of the obtained polyester was high.

Comparative Example 2
Low-weight is obtained by esterifying terephthalic acid (hereinafter referred to as TPA), 1,4-cyclohexanedicarboxylic acid (hereinafter referred to as CHDA) having a cis / trans isomer ratio of 75/25 and EG in a conventional manner (hereinafter referred to as ES). Coalescence was obtained. The acid value of the low polymer was measured and found to be 240 μeq / g. A phosphorus compound (B) and an alkali metal compound (A) were added to the low polymer. Next, SPG was added to cause ES reaction, and the reaction was transferred to a polycondensation reactor. Thereafter, the titanium compound (C) was added as a polycondensation reaction catalyst, and the polycondensation reaction was advanced in the same manner as in Example 14 to obtain a polyester and a film. However, during the polycondensation reaction, abnormal temperature in the decompression circuit, poor decompression, and droplet deposits were observed. In addition, the torque increased suddenly in the latter half of the reaction, resulting in poor discharge performance. The gelation rate of the polyester was high, the lamination was uneven, and the reflectance was slightly low.

Comparative Example 3
A polyester and a film were obtained in the same manner as in Example 1 except that the SPG of Example 1 was not contained, and 15 mol% of dimethyl isophthalate (hereinafter referred to as DMI) was copolymerized in place of the CHDC component. However, since neither an alicyclic dicarboxylic acid component nor an alicyclic diol component is contained, the refractive index, the photoelastic coefficient are large, and the reflectance is also small.

Comparative Example 4
Example 1 except that CHDC of Example 1 was not included, and 30 mol% of 1,4-cyclohexanedimethanol (hereinafter referred to as CHDM) was copolymerized in place of the SPG component (CHDM was added simultaneously with raw materials such as DMT). A polyester and a film were obtained in the same manner as in 1. However, since it does not contain an alicyclic dicarboxylic acid component, it has a large photoelastic coefficient and a low reflectance.

Comparative Example 5
A polyester and a film were obtained in the same manner as in Example 1 except that CHDC of Example 1 was not included and SPG was changed to 45 mol%. However, since it does not contain an alicyclic dicarboxylic acid, the Tg and gelation rate of the polyester is high, and the releasability is also high.

Comparative Example 6
A polyester and a film were obtained in the same manner as in Example 1 except that the SPG of Example 1 was not included and CHDC was changed to 25 mol%. However, since it does not contain an alicyclic diol, the Tg of the polyester is low, the peelability is high, and the reflectance is low.

Comparative Examples 7-12
A polyester and a film were obtained in the same manner as in Example 1 except that the amount of alkali metal compound (A), the amount of phosphorus compound (B), and the amount of titanium compound (C) in Example 1 were outside the scope of the present invention. In particular, since Comparative Example 7 did not add the alkali metal compound (A), the polyester had a high gelation rate and a low reflectance relative to the refractive index. In Comparative Example 8, since a large amount of the alkali metal compound (A) was added, the delay of the polycondensation reaction was remarkable and the reaction was advanced for 6 hours. However, the target torque was not obtained, so the reaction was stopped. In Comparative Example 9, since the amount of the phosphorus compound (B) is small, the amount of the titanium compound (C) as the polycondensation reaction catalyst was added in an amount close to the lower limit of the present invention. Occasionally thick guts occurred. Polyester had a high gelation rate. In Comparative Example 10, since the phosphorus compound (B) was added in a large amount, the amount of the titanium compound (C) as the polycondensation reaction catalyst was added in an amount close to the upper limit of the present invention, but the delay of the polycondensation reaction was remarkable. Although the time reaction was advanced, the target torque was not obtained, so the reaction was stopped. In Comparative Example 11, since the amount of the titanium compound (C) was small, the amount of the phosphorus compound (B) was added in an amount close to the lower limit of the present invention, but the delay of the polycondensation reaction was remarkable and the reaction was advanced for 6 hours. The reaction was stopped because no torque was obtained. In Comparative Example 12, since the amount of the titanium compound (C) was added in a large amount, the amount of the phosphorus compound (B) was added in an amount close to the upper limit of the present invention. Occurred. Polyester had a high gelation rate.

Comparative Examples 13 and 14
Comparative Example 13 was carried out except that the titanium compound (C) of the polycondensation reaction catalyst of Example 1 was changed to antimony trioxide (hereinafter referred to as Sb), and Comparative Example 14 was changed to germanium dioxide (hereinafter referred to as Ge dioxide). A polyester and a film were obtained in the same manner as in Example 1. Since both of the catalysts in the system had high acidity, the decomposition of SPG was promoted, the degree of vacuum was poor in the polycondensation reaction, the torque was suddenly increased, and fine guts were generated during discharge. Polyester had a high gelation rate.

Comparative Example 15
Since the order of addition of the phosphorus compound (B) and titanium compound (C) of the present invention in Example 1 was reversed, the delay of the polycondensation reaction was remarkable and the reaction was advanced for 6 hours, but the target torque was not obtained. The reaction was stopped.

Claims (8)

When a polyester satisfying the following characteristics (1) to (3) is produced by transesterification of a dicarboxylic acid component containing an alicyclic dicarboxylic acid and a diol component, followed by a polycondensation reaction, an alkali metal compound ( A polyester having a transesterification reaction in the presence of A), an alicyclic diol, a phosphorus compound (B), and a titanium compound (C) are sequentially added after the transesterification, followed by a polycondensation reaction. Production method.
Glass transition temperature by differential scanning calorimetry: 65 to 90 ° C. (1)
Refractive index at sodium D line: 1.500 to 1.570 (2)
Gelation rate: 10% or less (3)
(The gelation rate is the ratio of the amount of ortho-chlorophenol insoluble matter after the polyester is heat-treated at 280 ° C. for 2.5 hours under an oxygen concentration of 1%.)
Metal element content of (A): 5 to 200 ppm (vs. polyester)
Metal element content of (B): 10 to 300 ppm (vs. polyester)
(C) Metal element amount: 3 to 100 ppm (vs. polyester) The method for producing a polyester according to claim 1, wherein the titanium compound (C) is a titanium complex having a titanium alkoxide or hydroxycarboxylic acid as a chelating agent.   The method for producing a polyester according to claim 1 or 2, wherein the alicyclic dicarboxylic acid is dimethyl cyclohexanedicarboxylate and is 5 to 80 mol% of the total dicarboxylic acid component.   4. The method for producing a polyester according to claim 3, wherein the dimethyl cyclohexanedicarboxylate contains cis and trans isomers of stereoisomers, and the trans isomer content is 40% or less.   The method for producing a polyester according to any one of claims 1 to 4, wherein the alicyclic diol is spiroglycol and is 5 to 80 mol% in the diol component.   The method for producing a polyester according to any one of claims 1 to 5, wherein the molar number of aromatic rings contained in the repeating unit of the polyester is 4.8 mol or less per kg of the polyester resin.   The laminated polyester film which laminated | stacked the polyester obtained by the manufacturing method of the polyester of any one of Claims 1-6, and polyethylene terephthalate by turns.   The laminated polyester film according to claim 7, wherein the light reflectance is 90% or more.