JP2022105792A - Polyester resin composition and laminate film comprising the same - Google Patents

Abstract

To provide a polyester resin composition that is excellent in transparency, resistance to thermal degradation, and inhibition of gelling.SOLUTION: A polyester resin composition contains, as components of polyester, an aromatic dicarboxylic acid component, an alicyclic dicarboxylic acid component, an aliphatic diol component, and a diol component having an acetal ring. A molecular weight distribution dispersion of the polyester resin composition is 3.5 or less as measured by gel permeation chromatography.SELECTED DRAWING: None

Description

The present invention relates to a polyester resin composition and a laminated film comprising the polyester resin composition.

A film in which polymers having different refractive indexes are alternately laminated can efficiently reflect light having a specific wavelength, and is used as an optical filter or a reflector. The film is composed of at least two types of polymers, and a copolymerized polyester resin composition is used as the polymer used for a layer having a particularly low refractive index from the viewpoint of adjusting the refractive index and adhering between layers. However, the conventional copolymerized polyester resin composition has a low heat resistance, and has a problem that foreign matter is generated during melt extrusion during film production, which is a drawback of the film.

On the other hand, Patent Document 1 shows a polyester resin that can be used for an optical molded product, but the effect of suppressing gel generation during melt molding is not sufficient.

Subsequently, Patent Document 2 shows a polyester resin composition having excellent optical properties such as a low refractive index and suppressing gel generation by using a titanium catalyst, but at present, it is necessary to improve the quality of film products. The effect of suppressing gel generation is not sufficient.

Japanese Unexamined Patent Publication No. 2008-260963 Japanese Unexamined Patent Publication No. 2008-6417

An object of the present invention is to solve the above-mentioned conventional problems and to provide a polyester resin composition which is particularly excellent in transparency, heat-resistant decomposition property, and gel generation suppression.

In order to solve the above-mentioned problems, the present invention has the following features.
(1) As a constituent component of polyester, an aromatic dicarboxylic acid component, an alicyclic dicarboxylic acid component, an aliphatic diol component, and a diol component having an acetal ring are contained, and the degree of molecular weight distribution dispersion measured by gel permeation chromatography is high. A polyester resin composition of 3.5 or less.
(2) A laminated polyester film in which the polyester resin composition according to (1) and the polyethylene terephthalate resin composition are alternately laminated.

According to the present invention, it is possible to provide a polyester resin composition having excellent transparency, heat-decomposability, and suppression of gel generation. Further, the polyester resin composition of the present invention can be applied to optical reflector applications such as liquid crystal displays by biaxially stretching, and in particular, by forming a multilayer laminated film having a controlled refractive index, a total light reflection film, A heat ray reflecting film or the like can be provided.

The polyester resin composition of the present invention has an aromatic dicarboxylic acid component, an alicyclic dicarboxylic acid component, an aliphatic diol, and an acetal ring as constituent components from the viewpoints of crystal properties, thermal properties, transparency and refractive index control. It is necessary to contain a diol component. Since the resin composition made of polyethylene terephthalate has high crystallinity, it is oriented when stress is applied to the film, and the optical properties are changed. Therefore, by substituting a part of the copolymerization component with an alicyclic dicarboxylic acid component or a diol having an acetal ring, it is possible to carry out amorphous while maintaining a balance between the glass transition point and the refractive index.

Further, the polyester resin composition in the present invention has a molecular weight distribution calculated from a weight average molecular weight (Mw) and a number average molecular weight (Mn) measured by gel permeation chromatography from the viewpoint of suppressing gel defects generated during heat melting. The degree of dispersion (Mw / Mn) needs to be 3.5 or less. A polyester resin composition containing a diol component having an acetal ring as in the present invention may cause a side reaction to form a non-uniform structure or a crosslinked structure by heating in the manufacturing process, and this side reaction has a high degree of molecular weight distribution dispersion. It tends to be. When the degree of dispersion of the molecular weight distribution exceeds 3.5, it is suggested that there are many non-uniform structures and crosslinked structures, and decomposition and gelation due to these structures proceed, and defects occur when the film is formed. On the other hand, in the present invention, the timing of adding the diol having an acetal ring that easily forms a non-uniform structure or a crosslinked structure is set before the transesterification reaction or before the esterification reaction, after these reactions, for example, immediately before the polymerization reaction. The heating time of the diol having an acetal ring is shortened, and side reactions can be suppressed. Furthermore, since the diol having an acetal ring promotes a side reaction even when heated in the coexistence with the excess ethylene glycol, the excess ethylene glycol should be immediately distilled out of the reaction system after the addition of the diol having the acetal ring. Is also valid. By optimizing the production method in this way, it is possible to produce a polyester resin composition having a molecular weight distribution dispersity of 3.5 or less.

The aromatic dicarboxylic acid component in the present invention is an aromatic dicarboxylic acid or an ester-forming derivative thereof, for example, a terephthalic acid component, an isophthalic acid component, a 2,6-naphthalenedicarboxylic acid component, a 5-sulfoisophthalate sodium component. From the viewpoint of heat-resistant decomposition, a terephthalic acid component and a 2,6-naphthalenedicarboxylic acid component are preferable. In addition, these can be used not only in one type but also in combination of two or more types.

The alicyclic dicarboxylic acid component in the present invention is an alicyclic dicarboxylic acid or an ester-forming derivative thereof, and is a 1,4-cyclohexanedicarboxylic acid component from the viewpoint of the optical properties of the obtained polyester resin composition. Is preferable, and it is preferable that the content is 20 mol% or more and 50 mol% or less with respect to the total dicarboxylic acid component. The 1,4-cyclohexanedicarboxylic acid component is generally a mixture of a cis form and a trans form, but the ratio of the trans form is preferably 40% or less. The trans form easily affects the crystallinity of the obtained polyester composition, and the trans form ratio is preferably 35% or less, more preferably 30% or less. Further, as the other alicyclic carboxylic acid component, a decalindicarboxylic acid component can be applied as long as the effect of the invention is not impaired, and these may be used in combination of not only one type but also two types.

Examples of the aliphatic diol component in the present invention include ethylene glycol, propanediol, butanediol, neopentyl glycol and the like, and ethylene glycol is preferable from the viewpoint of heat-resistant decomposition.

The diol component having an acetal ring in the present invention is preferably a spiroglycol component from the viewpoint of heat resistance and color tone. Here, spiroglycol refers to 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane. The content of spiroglycol is preferably 10 mol% or more and 30 mol% or less with respect to the total diol component from the viewpoint of the glass transition temperature and the refractive index. Further, other diol components having an acetal ring can be applied as long as the effects of the invention are not impaired, and these may be used in combination of not only one type but also two or more types.

The polyester resin composition of the present invention can be produced by an esterification method or an ester exchange method, but in the case of the ester exchange method, magnesium compounds, manganese compounds, cobalt compounds, lithium compounds and titanium are used as metal compounds for the reaction catalyst. Examples thereof include compounds and calcium compounds, and it is preferable to use manganese compounds and magnesium compounds from the viewpoint of transparency and polymer color tone. In addition, these can be used not only in one type but also in combination of two or more types.

In the polyester resin composition of the present invention, a conventionally known compound can be used as a polymerization reaction catalyst, but it is preferable to use a titanium compound from the viewpoint of thermal decomposition resistance and polymerization reactivity. Further, the content of titanium atoms is preferably 5 ppm or more and 100 ppm or less, and more preferably 8 ppm or more and 90 ppm or more as a weight ratio with the obtained composition. If the amount of titanium is less than 5 ppm, the polymerization reaction does not proceed sufficiently and stays at a high temperature for a long time, so that the heat-resistant decomposition property and the color tone tend to deteriorate. On the other hand, if it exceeds 100 ppm, the amount of metal contained increases and thermal decomposition is promoted, so that the thermostable decomposition property tends to deteriorate, and coloring of the polymer also tends to occur.

In the polyester resin composition of the present invention, as a suitable titanium catalyst, a titanium compound in which the substituent is at least one of an alkoxy group, a phenoxy group, an acylate group, an amino group and a hydroxyl group is preferably used.

Specific alkoxy groups include titanium tetraalkoxides such as tetraethoxydo, tetrapropoxide, tetraisopropoxide, tetrabutoxide, tetra-2-ethylhexoxide, β-diketone functional groups such as acetylacetone, lactic acid, and the like. Examples thereof include hydroxy polyvalent carboxylic acid-based functional groups such as malic acid, tartaric acid, salicylic acid and citric acid, and ketoester-based functional groups such as methyl acetoacetate and ethyl acetoacetate, and an aliphatic alkoxy group is particularly preferable. Further, examples of the phenoxy group include phenoxy, cresilate and the like. In addition, the acylate group includes tetraacylate groups such as lactate and stearate, phthalic acid, trimellitic acid, trimesic acid, hemmellitic acid, pyromellitic acid, oxalic acid, malonic acid, succinic acid, glutaric acid and adipic acid. , Sevacinic acid, maleic acid, fumaric acid, 1,4-cyclohexanedicarboxylic acid or polyvalent carboxylic acid-based functional groups such as anhydrides thereof, ethylenediamine tetraacetic acid, nitrilotripropionic acid, carboxyiminodic acid, carboxymethyliminoni. Nitrogen-containing polyvalent carboxylic acid system such as propionic acid, diethylenetriaminopentaacetic acid, triethylenetetraminohexacetic acid, iminodiacetic acid, iminodipropionic acid, hydroxyethyliminodiacetic acid, hydroxyethyliminodipropionic acid, methoxyethyliminodiacetic acid, etc. Examples include functional groups, with aliphatic acylate groups being particularly preferred. Further, examples of the amino group include aniline, phenylamine, diphenylamine and the like. Further, examples thereof include diisopropoxybisacetylacetone and triethanolamineateisopropoxide containing two kinds of these substituents.

The polyester resin composition of the present invention preferably contains a phosphorus compound from the viewpoint of heat-resistant decomposition and color prevention. The phosphorus atom content is preferably 70 ppm or more and 300 ppm or less, and more preferably 90 ppm or more and 250 ppm or less as a weight ratio with the obtained composition. If the amount of phosphorus is less than 70 ppm, the heat-decomposability is insufficient, and if it exceeds 300 ppm, the polymerization reaction catalyst loses its catalytic activity and the polymerization reaction becomes difficult to proceed.

The phosphorus compound in the present invention is preferably a pentavalent phosphorus compound from the viewpoint of transparency. For example, phosphoric acid-based, phosphonic acid-based, phosphinic acid-based compounds and the like can be mentioned, and among them, these ester compounds are preferably used.

Specific pentavalent phosphorus compounds include phosphates such as phosphate, trimethyl phosphate, and triethyl phosphate, triphenyl phosphate, methylphosphonic acid, ethylphosphonic acid, propylphosphonic acid, isopropylphosphonic acid, and butylphosphonic acid. , Esterphosphonic acid, benzylphosphonic acid, trillphosphonic acid, xsilylphosphonic acid, biphenylphosphonic acid, naphthylphosphonic acid, anthrylphosphonic acid, 2-carboxyphenylphosphonic acid, 3-carboxyphenylphosphonic acid, 4-carboxyphenylphosphonic acid. Ester, 2,3-dicarboxyphenylphosphonic acid, 2,4-dicarboxyphenylphosphonic acid, 2,5-dicarboxyphenylphosphonic acid, 2,6-dicarboxyphenylphosphonic acid, 3,4-dicarboxyphenylphosphonic acid Acid, 3,5-dicarboxyphenylphosphonic acid, 2,3,4-tricarboxyphenylphosphonic acid, 2,3,5-tricarboxyphenylphosphonic acid, 2,3,6-tricarboxyphenylphosphonic acid, 2, 4,5-Tricarboxyphenylphosphonic acid, 2,4,6-tricarboxyphenylphosphonic acid, methylphosphonic acid dimethyl ester, methylphosphonic acid diethyl ester, ethylphosphonic acid dimethyl ester, ethylphosphonic acid diethyl ester, phenylphosphonic acid dimethyl ester, Phenylphosphonic acid diethyl ester, phenylphosphonic acid diphenyl ester, benzylphosphonic acid dimethyl ester, benzylphosphonic acid diethyl ester, benzylphosphonic acid diphenyl ester, lithium (3,5-di-tert-butyl-4-hydroxybenzylphosphonate ethyl) , Sodium (3,5-di-tert-butyl-4-hydroxybenzylphosphonate ethyl), magnesium bis (3,5-di-tert-butyl-4-hydroxybenzylphosphonate ethyl), calcium bis (3,5) -Di-tert-butyl-4-hydroxybenzylphosphonate ethyl), diethylphosphonoacetate ethyl, diethylphosphonoacetate methyl and other phosphonic acid-based compounds can be mentioned.
Further, the polyester resin composition in the present invention can contain an alkali metal phosphate from the viewpoint of heat-decomposability. The alkali metal phosphate salt in the present invention refers to a phosphorus compound containing an alkali metal among the positive salts of phosphates and hydrogen salts. Examples of such compounds include trisodium phosphate, disodium monohydrogen phosphate, monosodium dihydrogen phosphate, tripotassium phosphate, dipotassium monohydrogen phosphate, monopotassium dihydrogen phosphate, and trilithium phosphate. Examples thereof include dilithium monohydrogen phosphate and monolithium dihydrogen phosphate, and among them, monosodium dihydrogen phosphate, monopotassium dihydrogen phosphate and dipotassium monohydrogen phosphate are preferable from the viewpoint of heat resistance.

The polyester resin composition in the present invention preferably has an alkali metal atom content of 10 ppm or more and 300 ppm or less as a weight ratio from the viewpoint of heat-decomposability, transparency, and color tone of the polymer. It is preferably 30 ppm or more and 200 ppm or less. If the alkali metal content is less than 10 ppm, the heat-resistant decomposition property in the present invention is insufficient. On the other hand, if it exceeds 300 ppm, foreign matter formation and coloring of the polymer are likely to occur.

The polyester resin composition of the present invention preferably has an intermediate point (Tg) of glass transition temperature of 65 ° C. or higher and 90 ° C. or lower by differential scanning calorimetry from the viewpoint of film formation stability and thermal decomposition resistance, and further 70. It is preferably ° C. or higher and 85 ° C. or lower. When the Tg is less than 65 ° C., the heat-decomposable property is insufficient and the Tg difference when laminating PET or the like becomes large, resulting in uneven laminating. Similarly, when the Tg exceeds 90 ° C., uneven stacking or the like is likely to occur, and the film forming stability may be impaired.

The refractive index of the polyester resin composition of the present invention is preferably in the range of 1.500 or more and 1.570 or less, and more preferably in the range of 1.510 or more and 1.560 or less. If the refractive index is less than 1.510, the heat resistance of the polyester resin tends to deteriorate, and if it exceeds 1.570, the difference in refractive index from the high-refractive index polymer in the case of a laminated film becomes small. The light reflectivity of the laminated film is reduced. The refractive index in the present invention refers to the refractive index measured using a sodium D line under the condition of 23 ° C.

In the thermogravimetric analysis, the polyester resin composition of the present invention has a heat loss of 1% or less when the temperature is raised from room temperature to 290 ° C. at a rate of 20 ° C./min under a nitrogen atmosphere and held at 290 ° C. for 3 hours. It is preferable to have.

Hereinafter, a specific method for producing the polyester resin composition of the present invention will be described, but the present invention is not limited thereto.

In the case of the transesterification method, for example, dimethyl terephthalate, dimethyl 1,4-cyclohexanedicarboxylate, and ethylene glycol are charged into the transesterification reaction tank so as to have a predetermined polymer composition. In this case, if ethylene glycol is added 1.7 to 2.7 mol times with respect to the total dicarboxylic acid component, the reactivity becomes good. When the polyester resin composition of the present invention is used as a laminated film, it is preferable to match the Tg (intermediate point of the glass transition temperature) of the polyester resin composition of the present invention with the Tg of the other laminated polymer, and the Tg of the laminated polymer. The difference (| Tg1-Tg2 |) between (Tg1) and Tg (Tg2) of the polyester resin composition in the present invention is preferably 10 ° C. or less, more preferably 5 ° C. or less. To control the glass transition point, for example, in the case of copolymerization of dimethyl terephthalate, dimethyl 1,4-cyclohexanedicarboxylate, ethylene glycol, and spiroglycol, the amount of spiroglycol and / or the ratio of dimethyl terephthalate should be increased. The glass transition point becomes high, and when the proportion of ethylene glycol and / or dimethyl 1,4-cyclohexanedicarboxylate is increased, the glass transition point becomes low.
After melting these at about 150 ° C., manganese acetate or the like is added as a transesterification reaction catalyst. At 150 ° C., these monomer components become a uniform molten liquid. Next, methanol is distilled off while raising the temperature in the reaction vessel to 235 ° C., and a transesterification reaction is carried out. After the transesterification reaction is completed in this way, spiroglycol and potassium hydroxide are added, and the pressure is rapidly reduced to distill off excess ethylene glycol, and the obtained low polymer is transferred to the polymerization reaction tank.
After the transfer to the polymerization reaction tank is completed, a phosphorus compound such as ethyl diethylphosphonoacetate is added with stirring. Since the phosphorus compound scatters during the polymerization reaction, it is necessary to add an amount that allows for the amount of scatter.

A polymerization catalyst such as tetrabutyl titanate is added within 10 to 25 minutes after the addition of the phosphorus compound.

After the addition of the polymerization catalyst is completed, the pressure is reduced to distill off excess ethylene glycol, and then the pressure inside the device is reduced to 1 Torr or less while gradually raising the temperature inside the device to 280 ° C. The viscosity of the reactants increases as the polymerization reaction progresses. The reaction is terminated when the stirring torque increase value of the reactant reaches the polymerization termination target, and the polyester is discharged from the polymerization reaction tank to the water tank. The discharged polyester is rapidly cooled in a water tank and cut into chips with a cutter.

The polyester resin composition can be obtained in this way, but the above is an example, and the monomer, catalyst, and polymerization conditions are not limited thereto.

The polyester resin composition thus obtained is excellent in transparency and molecular weight distribution dispersity characteristics, and a film in which PET and the like are alternately laminated is excellent in light reflectivity and heat ray reflectivity, and is suitable for use as a reflective material. be.

Further, the laminated polyester film in which the polyester resin composition of the present invention and the polyethylene terephthalate resin composition are alternately laminated can be produced by the method exemplified below.
The polyester resin composition and PET resin of the present invention are vacuum-dried and then supplied to two extruders, respectively.

The polyester resin composition and the PET resin are each melted at 280 ° C. by an extruder, passed through a gear pump and a filter, and then merged with a feed block having 100 to 1000 layers. For example, in the case of 101 layers, it is preferable that both surface layers of the laminated film are PET resin layers, and the laminated thickness is alternately laminated so that the polyester resin composition layer / PET resin layer is halved. That is, it is preferable that the polyester resin composition layer is alternately laminated so as to be 50 layers and the PET layer is preferably 51 layers.

The laminate thus obtained is supplied to a die, extruded into a sheet, and rapidly cooled and solidified on a casting drum by electrostatic application.

The obtained cast film is guided to a roll-type longitudinal stretching machine, heated by a group of heated rolls, and stretched 2 to 5 times in the longitudinal direction between rolls having different peripheral speeds. The film that has been stretched in the vertical direction is then guided to a tenter type transverse stretching machine, preheated with hot air in the tenter, and stretched 2 to 5 times in the transverse direction. The stretched film is heat-treated with hot air in the tenter as it is. In this way, the laminated film can be obtained.

Hereinafter, the present invention will be described in more detail with reference to examples.

The method for measuring the physical properties and the method for evaluating the effect were as follows.

(1) Thermal properties of polyester (intermediate glass transition point, crystal properties)
Approximately 10 mg of the sample to be measured was weighed, sealed using an aluminum pan and a pan cover, and measured with a differential scanning calorimeter (DSC250 manufactured by TA Instruments Japan). 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 using liquid nitrogen, and again in a nitrogen atmosphere at a rate of 16 ° C./min from 20 ° C. to 285 ° C. The temperature rises. The midpoint of the glass transition point obtained in this second temperature rise process was measured. In the present invention, the intermediate point of the glass transition point (intermediate point glass transition temperature) is preferably 60 ° C. or higher and 90 ° C. or lower in order to suppress lamination unevenness when the laminated film is formed.

(2) Refractive index of polyester An unstretched sheet having a thickness of 100 μm is obtained by melt-extruding the polyester resin composition. Then, using a sodium D line as a light source, the refractive index was measured with an "Abbe-type refractive index meter NAR-4T" manufactured by Atago Co., Ltd. under a temperature condition of 23 ° C. In the present invention, the refractive index is preferably 1.500 or more and 1.570 or less from the viewpoint of heat resistance and light reflectivity.

(3) Intrinsic viscosity of polyester Dissolve the measurement sample in 10 ml of orthochlorophenol at 100 ° C (solution concentration C (measurement sample weight / solution volume) = 0.08 g / mL), and use a viscometer to dissolve 25 of the solution. The viscosity at ° C was measured. In addition, the viscosity of the solvent was measured in the same manner. Using the obtained solution viscosity and solvent viscosity, [η] was calculated by the following formula (α), and the obtained value was used as the intrinsic viscosity.
ηsp / C = [η] + K [η] 2 ・ C (α)
(Here, ηsp = (solution viscosity / solvent viscosity) -1, K is a Huggins constant (0.343)).
When the solution in which the measurement sample was dissolved contained insoluble substances such as inorganic particles, the measurement was carried out using the following methods (i) to (iv).
(I) Dissolve the measurement sample in 10 mL of orthochlorophenol to prepare a solution having a solution concentration higher than 0.08 g / mL. Here, the weight of the measurement sample used for orthochlorophenol is taken as the measurement sample weight.
(Ii) Next, the solution containing the insoluble matter is filtered, the weight of the insoluble matter is measured, and the volume of the filtrate after filtration is measured.
(Iii) Add orthochlorophenol to the filtered filtrate (measurement sample weight (g) -insoluble matter weight (g)) / (volume of filtered filtrate (mL) + added orthochlorophenol The volume (mL)) is adjusted to 0.08 g / mL.

(For example, when a concentrated solution having a measurement sample weight of 1.00 g / solution volume of 10 mL was prepared, the weight of the insoluble material when the solution was filtered was 0.02 g, and the volume of the filtrate after filtration was 9.9 mL. If so, make adjustments by adding 5.1 mL of orthochlorophenol ((1.00 g-0.20 g) / (9.9 mL + 0.1 mL) = 0.08 g / mL)).
(Iv) Measure the viscosity of the solution obtained in (iii) at 25 ° C. using a viscometer, and calculate [η] by the above formula (α) using the obtained solution viscosity and solvent viscosity. Then, the obtained value is used as the intrinsic viscosity.

As the viscometer, an automatic viscometer device (VMR-052UPC / F10) manufactured by Rigo Co., Ltd. was used.

(4) Polyester color tone The polyester chip was measured as a hunter value (b value) using a color difference meter (SM color computer model SM-T45 manufactured by Suga Test Instruments Co., Ltd.).

(5) Polymer haze value 2 g of polyester chip is dissolved in 20 ml of o-chlorophenol, and a quartz cell with an optical path length of 20 mm and a haze meter (HGM-2DP type manufactured by Suga Test Instruments Co., Ltd.) are used by an integrating sphere photoelectric photometric method. The haze value of the solution was measured.

(6) Degree of Dispersity of Molecular Weight Distribution A solution prepared by dissolving 2.5 mg of polyester chips in 3 ml of a hexafluoroisopropanol mobile phase solution (hexafluoroisopropanol in which sodium trifluoroacetate is dissolved at 0.042% by weight) has a pore size of 0. The sample solution was filtered through a membrane filter made of .45 μm polytetrafluoroethylene.
The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the sample solution were measured with a gel permeation chromatograph (e2695) manufactured by Waters Corp. at a column temperature of 30 ° C. and a flow rate of 1 ml / min. The column was measured using a column for organic solvent-based SEC (GPC) manufactured by Showa Denko (Shodex_HFIP_806M), and a calibration curve of monodisperse standard polymethyl methacrylate was used as the molecular weight standard. The molecular weight distribution dispersion (Mw / Mn) was calculated from the obtained Mw and Mn, and in the present invention, only when this value was 3.5 or less was judged as acceptable.

(7) Thermal weight loss of polymer (mass ratio wt% to polyester resin composition)
When 10 mg of the polyester resin composition was weighed in an aluminum pan, heated from room temperature to 290 ° C (20 ° C / min) under nitrogen flow (200 ml / min) under HITACHI: STA7200RV, and maintained at 290 ° C for 3 hours. The rate of weight loss was measured using TG-DTA.

(8) Gelation rate (mass ratio wt% to polyester composition)
The polyester composition was pulverized by a freeze crusher (manufactured by Splex CertiPerp), and 0.5 g was weighed in a stainless beaker having a capacity of 50 ml. After vacuum drying at 50 ° C. for 2 hours using a vacuum dryer, heat treatment was performed at 280 ° C. for 24 hours under nitrogen gas flow (flow rate 0.5 L / min). This was dissolved in 20 ml of o-chlorophenol at 160 ° C. for 1 hour and allowed to cool. This solution was filtered using a glass filter (3GP40 manufactured by Shibata Scientific Technology Co., Ltd.), and the glass filter was washed with dichloromethane. The glass filter was dried at 130 ° C. for 2 hours, and the weight fraction with respect to the polyester weight (0.5 g) was obtained from the increase in the weight of the filter before and after filtration, and the gelation ratio was used.

Example 1
(Polyester synthesis)
56.1 parts by weight of dimethyl terephthalate, 24.8 parts by weight of dimethyl 1,4-cyclohexanedicarboxylate, and 51.2 parts by weight of ethylene glycol were weighed and charged into a transesterification reaction vessel. The contents were dissolved at 150 ° C. and stirred. 0.06 part by weight of manganese acetate tetrahydrate was added to start the transesterification reaction.

Methanol was distilled off while raising the temperature of the reaction contents to 220 ° C. by a specified temperature raising program while stirring. After distilling off a predetermined amount of methanol, the temperature was raised to 230 ° C. in 30 minutes while distilling off excess ethylene glycol. Then, 25.1 parts by weight of spiroglycol and 0.005 part by weight of potassium hydroxide were added, and the pressure was rapidly reduced to 100 Torr to distill off excess ethylene glycol to obtain a low polymer.

After transferring the obtained low polymer to a polymerization reaction vessel at 235 ° C., 0.085 parts by weight of ethyl diethylphosphonoacetate, which is a phosphorus compound, was added with stirring, and after 15 minutes, 0.021 parts by weight of tetrabutoxytitanium was added. After partial addition, the pressure was reduced to 100 Torr 5 minutes later to distill off excess ethylene glycol, then the temperature was gradually raised to 285 ° C. and the pressure was reduced, and the polymerization reaction was carried out while distilling ethylene glycol. The final pressure was 0.1 Torr.

When the stirring torque of the polymerization apparatus reached a predetermined value, the inside of the polymerization reaction tank was returned to normal pressure with nitrogen gas, and the gut-shaped polymer was discharged into the water tank. The polyester gut cooled in the water tank was cut with a cutter to obtain a polyester resin composition A.

The obtained polyester resin composition A has a refractive index of 1.545, a glass transition point of 78 ° C., a solution haze of 1.1%, a b value of 11.0, an intrinsic viscosity of 0.70, and a molecular weight distribution dispersity of 3. 1. The heat loss was 0.81%.

(Film formation of laminated polyester film)
The polyester resin composition A and the PET resin were vacuum-dried and then supplied to two extruders, respectively.

The polyester resin composition A and the PET resin were each melted at 280 ° C. by an extruder, passed through a gear pump and a filter, and then merged with a 101-layer feed block. At this time, both surface layers of the laminated film were laminated as PET resin layers, and the laminated thickness was alternately laminated so that the polyester resin composition A layer / PET resin layer was halved. That is, the polyester resin composition A layer was alternately laminated so as to be 50 layers, and the PET layer was alternately laminated so as to be 51 layers.

The laminated body composed of 101 layers 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 guided 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 longitudinal direction was then led to a tenter type transverse stretching machine. The film was preheated in a tenter with hot air at 100 ° C. and stretched 3.3 times in the lateral direction. The stretched film was directly heat-treated in a tenter with hot air at 200 ° C. In this way, a film having a thickness of 50 μm could be obtained. Since the polyester composition of the present invention has a low refractive index, it has excellent light reflectivity when made into a laminated film.

Examples 2-4
When a polyester resin composition was obtained in the same manner as in Example 1 except that the copolymerization ratio of the spiroglycol component was changed, when the copolymerization ratio of the spiroglycol component was reduced, the molecular weight distribution dispersity was lowered and the refractive index was increased. On the contrary, when the copolymerization ratio was increased, the molecular weight distribution became higher, but all of them were within the range where there was no problem.

Examples 5 and 6, Comparative Examples 1 and 2
A polyester resin composition was obtained in the same manner as in Example 1 except that the copolymerization ratio of the cyclohexanedicarboxylic acid component was changed.

In Examples 5 and 6, when the copolymerization ratio of the cyclohexanedicarboxylic acid component was reduced, the glass transition point increased, and conversely, when the copolymerization ratio was increased, the polymerization reaction time became longer, but all of them were within the range where there was no problem. there were.

In Comparative Example 1, when the copolymerization ratio of the cyclohexanedicarboxylic acid component was set to 0, the molecular weight distribution dispersion degree was 4.2, which was out of the acceptable range.

In Comparative Example 2, when the copolymerization ratio of the cyclohexanedicarboxylic acid component was set to 60 mol% as the dicarboxylic acid component, the polymerization reaction did not proceed and the polymer could not be obtained.

Example 7
When a polyester resin composition was obtained in the same manner as in Example 1 except that the transesterification reaction catalyst was changed from manganese acetate tetrahydrate to magnesium acetate tetrahydrate, various properties were good.

Example 8
When a polyester resin composition was obtained in the same manner as in Example 1 except that two types of transesterification reaction catalysts, manganese acetate tetrahydrate and magnesium acetate tetrahydrate, were used in combination, various properties were good.

Examples 9-11
The polyester resin composition was prepared in the same manner as in Example 1 except that the ester exchange reaction catalyst was changed from manganese acetate tetrahydrate to magnesium acetate tetrahydrate and an alkali metal phosphate was used as a part of the phosphorus compound. As a result, various characteristics were good.

Comparative Example 3
56.1 parts by weight of dimethyl terephthalate, 24.8 parts by weight of dimethyl 1,4-cyclohexanedicarboxylate, 51.2 parts by weight of ethylene glycol, 25.1 parts by weight of spiroglycol, 0.005 parts by weight of potassium hydroxide. Weighed and charged into the transesterification reaction tank. The contents were dissolved at 150 ° C. and stirred. 0.06 part by weight of manganese acetate tetrahydrate was added, and the transesterification reaction was carried out in the same manner as in Example 1 to obtain a low polymer.

After transferring the obtained low polymer to the polymerization reaction tank, 0.085 parts by weight of ethyl diethylphosphonoacetate, which is a phosphorus compound, was added with stirring, and after 15 minutes, 0.021 parts by weight of tetrabutoxytitanium was added. After 5 minutes, the temperature was gradually raised to 285 ° C. and the pressure was reduced, and the polymerization reaction and cutting were carried out in the same manner as in Example 1 to obtain a polyester resin composition.
The obtained polyester resin composition had a molecular weight distribution dispersion of 3.6, which was out of the acceptable range.

Comparative Example 4
Dimethyl terephthalate was weighed in 62.0 parts by weight, ethylene glycol in an amount of 24.8 parts by weight, and spiroglycol in an amount of 48.6 parts by weight, and charged into a transesterification reaction vessel. The contents were dissolved at 150 ° C. and stirred. 0.03 part by weight of manganese acetate tetrahydrate was added, and the transesterification reaction was carried out in the same manner as in Example 1 to obtain a low polymer.

After transferring the obtained low polymer to a polymerization reaction tank at 235 ° C., 0.01 part by weight of antimony trioxide and 0.06 part by weight of triphenyl phosphate were added while stirring, and the temperature was gradually raised to 285 ° C. And the pressure was reduced, and the polymerization reaction and cutting were carried out in the same manner as in Example 1 to obtain a polyester resin composition.

The obtained polyester resin composition did not contain the alicyclic carboxylic acid component which is an essential component in the present invention, and had a molecular weight distribution dispersity of 6.3, which was out of the acceptable range.

Comparative Example 5
95.1 parts by weight of dimethyl terephthalate, 72.2 parts by weight of ethylene glycol, and 7.5 parts by weight of spiroglycol were weighed and charged into a transesterification reaction vessel. The contents were dissolved at 150 ° C. and stirred. 0.03 part by weight of manganese acetate tetrahydrate was added, and the transesterification reaction was carried out in the same manner as in Example 1 to obtain a low polymer.

After transferring the obtained low polymer to a polymerization reaction tank at 235 ° C., 0.01 part by weight of antimony trioxide and 0.06 part by weight of triphenyl phosphate were added while stirring, and the temperature was gradually raised to 285 ° C. And the pressure was reduced, and the polymerization reaction and cutting were carried out in the same manner as in Example 1 to obtain a polyester resin composition.

The degree of molecular weight distribution dispersion of the obtained polyester resin composition was within the range of no problem, but the gelation rate deteriorated because the alicyclic carboxylic acid component, which is an essential component in the present invention, was not contained.

Claims (7)

As a constituent component of polyester, an aromatic dicarboxylic acid component, an alicyclic dicarboxylic acid component, an aliphatic diol component, and a diol component having an acetal ring are contained, and the molecular weight distribution dispersion measured by gel permeation chromatography is 3.5 or less. Is a polyester resin composition. The polyester resin composition according to claim 1, wherein the diol component having an acetal ring is spiroglycol. The polyester resin composition according to claim 1 or 2, which contains 20 mol% or more and 50 mol% or less of a cyclohexanedicarboxylic acid component with respect to the total dicarboxylic acid component. The polyester resin composition according to any one of claims 1 to 3, wherein the intermediate point glass transition point temperature measured by differential scanning calorimetry is 65 ° C. or higher and 90 ° C. or lower. The polyester resin composition according to any one of claims 1 to 4, wherein the refractive index of the sodium D line is 1.500 or more and 1.570 or less. In the thermogravimetric analysis, any one of claims 1 to 5 in which the heat loss is 1% or less when the temperature is raised from room temperature to 290 ° C. at a rate of 20 ° C./min under a nitrogen atmosphere and held at 290 ° C. for 3 hours. The polyester resin composition according to. A laminated polyester film in which the polyester resin composition according to any one of claims 1 to 6 and the polyethylene terephthalate resin composition are alternately laminated.