JP6115188B2 - Method for producing polyester film and polyester resin composition - Google Patents

Description

  The present invention relates to a polyester film and a method for producing a polyester resin composition, and more specifically, a polyester film having good appearance containing organic crosslinked polymer particles, and a polyester resin composition containing organic crosslinked polymer particles suitable as a forming raw material for the polyester film. The present invention relates to a method for manufacturing a product.

  Polyester films, especially polyethylene terephthalate and polyethylene naphthalate films, have excellent transparency, mechanical properties, heat resistance, and chemical resistance. Used for base films such as prism lens sheets, touch panels, backlights, antireflection films, plasma display electromagnetic wave shielding films, organic EL display base films, display explosion-proof base films, etc. . The polyester film used for such an optical film is required not only to have a good appearance including transparency, but also to improve workability during film handling, that is, to reduce the friction coefficient and to improve the wear characteristics.

Reduction of the coefficient of friction and improvement of wear characteristics of the film can be realized by a method in which inert fine particles are mixed in polyester. This method is roughly classified into a method of precipitating metal compound fine particles in the system during polycondensation and a method of adding inorganic or organic fine particles such as calcium carbonate, kaolin, silica, and organic cross-linked polymer from the outside.
Among these, attempts have been made to use organic crosslinked polymer particles having a refractive index that is relatively close to that of the raw material polyester in order to obtain a highly transparent polyester film (see, for example, Patent Document 1).

  However, these organic cross-linked polymer particles do not necessarily exhibit good dispersibility in the polyester, and often agglomerate into coarse particles that cause the agglomerates to significantly deteriorate the appearance of the film. In order to prevent aggregation of the organic crosslinked polymer particles in the polyester, 0.1 to 10 times (mass ratio) of the aluminum oxide fine particles and / or the organic crosslinked polymer particles at any time before the polycondensation stage. Alternatively, a method for producing a polyester by separately adding an ethylene glycol slurry containing an aluminate and an ethylene glycol slurry containing an organic crosslinked polymer particle has been proposed (see, for example, Patent Document 2).

  Further, an aqueous slurry of organic crosslinked polymer particles and an aqueous slurry of aluminum oxide fine particles were prepared, the ζ potential of each slurry was adjusted, and both were mixed and stirred and held for several hours. There has been proposed a method for producing a polyester using an ethylene glycol slurry of composite particles prepared by adding ethylene glycol and distilling off water under heating and reduced pressure after forming composite particles of fine particles (for example, And Patent Document 3).

JP 2006-16422 A Japanese Patent Laid-Open No. 3-100017 JP-A-6-64034

  However, as practiced in Patent Document 2, an ethylene glycol slurry of organic crosslinked polymer particles and an ethylene glycol slurry of aluminum oxide fine particles may be added after being subjected to treatments such as pulverization, classification and filtration, respectively. When the ethylene glycol slurry is added separately, the organic crosslinked polymer particles aggregate in the polyester, and the appearance of the polyester film obtained using the polyester as a raw material may be impaired by the aggregated particles.

  Further, the method of Patent Document 3 tends to cause aggregation of particles in the water slurry preparation stage, the water removal stage, etc. In addition, the method of distilling water after adding the tyrene glycol is complicated in operation, and it is effective in removing water. Since a great deal of energy is required, it is not always a preferable method.

  An object of the present invention is to provide a polyester film having a good appearance even when organic crosslinked polymer particles and aluminum oxide fine particles are used in combination, and a method for producing a polyester suitable for forming the film.

  In view of the above problems, the present inventors have studied the prevention of aggregation of organic crosslinked polymer particles added during the polyester production reaction as a raw material for the polyester film. As a result, when producing the polyester as the raw material for the polyester film, By dispersing each molecule and aluminum oxide fine particles in ethylene glycol as a slurry, mixing each slurry, and adding the ethylene glycol slurry mixture at an arbitrary production stage, organic crosslinked polymer particles in polyester can be easily obtained. It has been found that a polyester film having a very good appearance can be obtained from the polyester composition produced by this method, and the present invention has been completed.

That is, the present invention is as follows.
[1] A polyester film formed by molding a polyester resin composition containing organic cross-linked polymer particles and aluminum oxide fine particles, the polyester film being 0.7 mm × at a magnification of 160 times using a differential interference microscope A polyester film characterized in that aggregates of organic crosslinked polymer particles of 20 μm or more are not confirmed in all visual fields when 20 visual fields of 0.825 mm are observed.
[2] The polyester film as described in [1], which is obtained by molding a polyester resin composition obtained using dimethyl terephthalate.
[3] The polyester resin composition is produced by adding organic cross-linked polymer particles having a volume average particle size of 0.01 to 3 μm, as described in [1] or [2] Polyester film.
[4] The polyester film according to any one of [1] to [3], wherein the content of the organic crosslinked polymer particles is 0.1 to 1.0% by mass relative to the polyester in the polyester film. .
[5] The polyester resin composition is produced by adding aluminum oxide fine particles having a volume average particle diameter of 0.001 to 1 μm, and any one of [1] to [4] Polyester film.
[6] The polyester according to any one of [1] to [5], wherein the ratio of the volume average particle diameter of the aluminum oxide fine particles to the volume average particle diameter of the organic crosslinked polymer particles is 1/2 or less. the film.
[7] The polyester film according to any one of [1] to [6], wherein the content of the aluminum oxide fine particles with respect to the content of the organic crosslinked polymer particles is 0.1 to 10 times by mass.
[8] Esterification in which a polyester low polymer is obtained by esterification and / or transesterification of a dicarboxylic acid component mainly composed of terephthalic acid or an ester-forming derivative thereof and a diol component mainly composed of ethylene glycol. Ethylene glycol slurry containing both organic crosslinked polymer particles and aluminum oxide fine particles in a process for producing a polyester containing organic crosslinked polymer particles, comprising a step of polycondensation of the resulting polyester low polymer to obtain a polyester Is added to any stage of the production process of the organic cross-linked polymer particle-containing polyester.
[9] An ethylene glycol slurry containing both organic crosslinked polymer particles and aluminum oxide fine particles is prepared by mixing an ethylene glycol slurry of aluminum oxide fine particles and an ethylene glycol slurry containing organic crosslinked polymer particles. [8] The production method according to [8].
[10] The method according to [8] or [9], wherein the ester-forming derivative is dimethyl terephthalate.
[11] The production method according to any one of [8] to [10], wherein the organic crosslinked polymer particles have a volume average particle size of 0.01 to 3 μm.
[12] The production method according to any one of [8] to [11], wherein the addition amount of the organic crosslinked polymer particles is 0.1 to 3.0% by mass with respect to the polyester.
[13] The production method according to any one of [8] to [12], wherein the volume average particle diameter of the aluminum oxide fine particles is 0.001 to 1 μm.
[14] The production according to any one of [8] to [13], wherein the ratio of the volume average particle size of the aluminum oxide fine particles to the volume average particle size of the organic crosslinked polymer particles is ½ or less. Method.
[15] The production method according to any one of [8] to [14], wherein the addition amount of the aluminum oxide fine particles is 0.1 to 10 times by mass with respect to the addition amount of the organic crosslinked polymer particles. .
[16] A polyester film obtained by molding a polyester resin composition obtained by the production method according to any one of [8] to [15].
[17] The polyester resin composition obtained by the production method according to any one of [8] to [15] and a polyester not containing organic crosslinked polymer particles are mixed and further molded. A polyester film.
[18] When 20 visual fields of 0.7 mm × 0.825 mm are observed using a differential interference microscope at a magnification of 160, no aggregates of organic crosslinked polymer particles of 20 μm or more are observed in all visual fields. The polyester film as described in [16] or [17].

  According to the present invention, by adding an ethylene glycol slurry containing both organic crosslinked polymer particles and aluminum oxide fine particles at any time during the production process of the organic crosslinked polymer particle-containing polyester, Inhibition of aggregation of the organic crosslinked polymer particles in the polyester can be easily achieved, and a polyester film having a good appearance and a low coefficient of friction can be obtained from this polyester composition. Therefore, the industrial value of the present invention is high. Among them, the film of the present invention is particularly useful as an optical film because it is excellent in transparency, has no aggregate of 20 μm or more, and has excellent wear characteristics.

Differential interference micrograph of the surface of the polyester film obtained in Example 1 (160 times) Differential interference micrograph of the surface of the polyester film obtained in Comparative Example 1 (160 times) Differential interference micrograph of the surface of the polyester film obtained in Comparative Example 2 (160 times)

Hereinafter, the present invention will be described in detail. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and is not limited to these contents.
In the present invention, the average particle diameter means a volume average particle diameter unless otherwise specified.

(Polyester film)
The polyester film of the present invention is a polyester film formed by molding a polyester resin composition containing organic crosslinked polymer particles and aluminum oxide fine particles, and the polyester film is obtained at a magnification of 160 times using a differential interference microscope. When 20 visual fields of 0.7 mm × 0.825 mm are observed, aggregates of organic crosslinked polymer particles of 20 μm or more are not confirmed in all visual fields. The film in the present invention refers to a film having a thickness of 1 to 500 μm.

Here, in order to observe the presence or absence of the aggregate of the organic crosslinked polymer particles contained in the polyester film, a differential interference microscope is used. A differential interference microscope observes an object using the principle of interference spectroscopy. By observing with a differential interference microscope, the organic cross-linked polymer particles contained in the polyester film are compared with other optical microscopes. The outline has a feature that is easy to observe.
Moreover, in order to confirm the presence or absence of the aggregate of the organic crosslinked polymer particles contained in the polyester film, 20 visual fields of 0.7 mm × 0.825 mm are observed with a magnification of 160 times using a differential interference microscope. A film with a full width is sampled and observed 20 times at different locations.

  The polyester resin composition that is a raw material of the polyester film of the present invention may be produced by any method as long as it contains organic crosslinked polymer particles and aluminum oxide fine particles, but is obtained using dimethyl terephthalate. The thing manufactured by the below-mentioned method is preferable.

The polyester resin composition obtained by the method described later can be directly molded to obtain the polyester film of the present invention. On the other hand, a polyester film is obtained by mixing the polyester resin composition and a polyester containing no organic cross-linked polymer particles and then directly molding the molded polyester resin composition or once forming a granular polyester resin composition. You can also.
The polyester film can be produced using a known method. As the molding method, a known film production method can be applied. For example, a polyester sheet can be obtained by extrusion molding after melting at a temperature equal to or higher than the melting point of the polyester. Furthermore, the obtained polyester sheet can be biaxially stretched to obtain a polyester film.

  The content of the organic crosslinked polymer particles contained in the polyester film of the present invention is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and particularly preferably 0.3% by mass or more. If the content is less than the lower limit, the amount of organic crosslinked polymer particles contained in the polyester film may be too small to improve the running property and wear resistance. Further, the content of the organic crosslinked polymer particles is preferably 1.0% by mass or less, more preferably 0.8% by mass or less, and particularly preferably 0.6% by mass or less. If the content exceeds the upper limit, the amount of organic cross-linked polymer particles added in the polyester film becomes too large, and the organic cross-linked polymer particles tend to aggregate, which may result in a polyester film with poor transparency and poor appearance. In addition, agglomerates of organic crosslinked polymer particles may fall off from the film due to friction during normal film handling and cause defects on the film surface.

In the polyester film of the present invention, the content of the aluminum oxide fine particles relative to the content of the organic crosslinked polymer particles is preferably 0.1 to 10 times by mass ratio, and is preferably in the range of 0.3 to 5 times. Particularly preferred. Similar to the behavior in the polyester resin composition, if this value is less than the lower limit value, there is a tendency to aggregate in the film. Even if the upper limit is exceeded, dispersibility in the film is no longer improved, and conversely, the aggregation of aluminum oxide fine particles Coarse particles are likely to occur.
In the polyester film of the present invention, the ratio of the volume average particle diameter of the aluminum oxide fine particles to the volume average particle diameter of the organic crosslinked polymer particles is preferably 1/2 or less, more preferably 1/5 or less, / 10 or less is particularly preferable. If this ratio is less than the lower limit, the effect of preventing aggregation of the organic crosslinked polymer particles by the aluminum oxide fine particles cannot be obtained, and the appearance of the polyester film may be remarkably deteriorated. The lower limit is not particularly limited, but is determined by the lower limit of the volume average particle diameter of the aluminum oxide fine particles.

The polyester resin composition that is a raw material for the polyester film of the present invention is preferably produced by adding organic crosslinked polymer particles having a volume average particle size of 0.01 to 3 μm, as described later. The volume average particle diameter of the organic crosslinked polymer particles contained in the polyester film is not necessarily in the range of 0.01 to 3 μm. Similarly, the polyester resin composition is preferably prepared by adding aluminum oxide fine particles having a volume average particle diameter of 0.001 to 1 μm as described later, but the organic crosslinked polymer contained in the polyester film is used. The volume average particle diameter of the particles is not necessarily in the range of 0.001 to 1 μm.
Details of the properties and contents of the organic crosslinked polymer particles and aluminum oxide fine particles described above are as described later.

(Polyester resin composition)
In the present invention, the concentration of the organic crosslinked polymer particles contained in the polyester resin composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and particularly preferably 0.3% by mass or more. . When the polyester resin composition obtained when the concentration is less than the lower limit is molded into a polyester film, the polyester film surface has too few irregularities caused by the organic crosslinked polymer particles contained in the polyester film, and the polyester film has runability And wear resistance may not be improved. The concentration of the organic crosslinked polymer particles contained in the polyester resin composition is preferably 3.0% by mass or less, more preferably 2.0% by mass or less, and particularly preferably 1.5% by mass or less. When the upper limit is exceeded, even if the production method of the present invention is used, aggregation of the organic crosslinked polymer particles in the polyester resin composition cannot be prevented, and the aggregated organic crosslinked polymer particles when formed into a polyester film It may become a polyester film with poor appearance.

  The polyester resin composition obtained in the present invention can also be used as a master batch of organic crosslinked polymer particles. That is, a polyester resin composition containing a relatively high concentration of organic crosslinked polymer particles in the production of polyester is produced, and this polyester resin composition is appropriately diluted with a polyester resin not containing organic crosslinked polymer particles to obtain a film raw material. I can do it. The concentration of the organic crosslinked polymer particles contained in the polyester resin composition containing the organic crosslinked polymer particles is preferably 3.0% by mass or less, more preferably 2.0% by mass or less, and 1.5% A mass% or less is particularly preferred. If the concentration exceeds the upper limit value, it is impossible to prevent aggregation of the organic crosslinked polymer particles in the production of the polyester resin composition, and a polyester film having a poor appearance due to the aggregated organic crosslinked polymer particles when formed into a polyester film. May be. On the other hand, the lower limit of the concentration may be set so as not to be lower than the lower limit when the polyester resin composition is mixed with a polyester resin not containing organic crosslinked polymer particles.

(Ethylene glycol slurry of organic crosslinked polymer particles and preparation method thereof)
In the present invention, an ethylene glycol slurry containing both organic crosslinked polymer particles and aluminum oxide fine particles (hereinafter sometimes referred to as “slurry mixture”) is added to any stage of the production process of the polyester containing organic crosslinked polymer particles. To do.

・ Organic crosslinked polymer particles:
In the present invention, the organic crosslinked polymer particles are not limited in shape, composition and production method, and organic crosslinked polymer particles having various shapes and compositions obtainable from various methods can be used.
Typical examples of the composition of the organic crosslinked polymer particles used in the present invention include a vinyl compound (A) having one aliphatic unsaturated bond in the molecule and two or more aliphatic compounds in the molecule as a crosslinking agent. A copolymer with the compound (B) having an unsaturated bond can be exemplified.
The organic crosslinked polymer particles used in the present invention must be substantially insoluble, infusible and heat resistant even at high temperatures during the production or molding of polyester. Specifically, the mass reduction rate after 30 minutes of heat treatment at 300 ° C. under nitrogen gas flow is 30% by mass or less, preferably 20% by mass or less. Therefore, the organic crosslinked polymer particles used in the present invention preferably have a crosslinked structure, and are preferably a copolymer of the vinyl compound (A) and the compound (B).

  Examples of the vinyl compound (A), which is a component of the copolymer, include acrylic acid, methacrylic acid, and methyl or glycidyl esters thereof, maleic anhydride and alkyl derivatives thereof, vinyl glycidyl ether, vinyl acetate, styrene, and alkyl. Examples thereof include substituted styrene. Moreover, as said compound (B), divinylbenzene, divinyl sulfone, ethylene glycol dimethacrylate, etc. can be mentioned. One or more of each of the vinyl compound (A) and the compound (B) can be used. Moreover, in order to suppress the production | generation of the void which reduces film transparency, when crosslinking components, such as divinylbenzene of a compound (B), are processed into a polyester film, 10 mass% or less is preferable.

  Typical examples of the organic crosslinked polymer particles used in the present invention include methyl methacrylate and divinylbenzene, methyl acrylate and divinylbenzene, a copolymer of styrene and divinylbenzene, or an ethylene glycol unit introduced in these systems. Can be mentioned.

  There is no restriction | limiting in particular also about the manufacturing method of the organic bridge | crosslinking polymer particle used by this invention, Any of suspension polymerization, emulsion polymerization, soap free emulsion polymerization, etc. may be used. In that case, for example, azobisisobutyronitrile, benzoyl peroxide, t-butyl peroxide, cumene hydroperoxide, hydrogen peroxide, potassium persulfate, potassium persulfate-sodium thiosulfate, or the like is used as the polymerization initiator. be able to. Furthermore, there is no restriction | limiting in shape, You may use any of spherical shape, a spindle shape, an indeterminate form, etc.

  The organic crosslinked polymer particles used in the present invention can be introduced with various functional groups by surface treatment in order to further increase the affinity with polyester. Examples of the functional group include a carboxyl group, a hydroxyl group, an amide group, and a sulfonic acid group. The introduction of the functional group is preferably carried out using methacrylic acid for the carboxyl group, acrylic monomer for the hydroxyl group, methacrylamide for the amide group, and styrene sulfonic acid for the sulfonic acid group.

  The volume average particle diameter of the organic cross-linked polymer particles used in the present invention is preferably 0.01 μm or more, more preferably 0.1 μm or more, and particularly preferably 0.3 μm or more in a state where it is mixed with ethylene glycol to form a slurry. . If the volume average particle size is less than the lower limit, the running property and wear resistance may not be improved when molded into a polyester film. On the other hand, the volume average particle size of the organic crosslinked polymer particles used in the present invention is preferably 3 μm or less, more preferably 2.5 μm or less, and further preferably 2.0 μm or less in a state where the volume average particle size is mixed with an ethylene glycol slurry. preferable. If the average particle size exceeds the upper limit, the surface roughness of the polyester becomes too large, and the surface of the polyester film may be damaged and transparency may be impaired.

  The volume average particle diameter of the organic crosslinked polymer particles used in the present invention is determined by diluting an ethylene glycol slurry of the organic crosslinked polymer particles with a large amount of water to obtain an aqueous dispersion. The particle diameter when the volume fraction reaches 50% is defined as the volume average particle diameter. Here, a large amount of water used for measuring the particle size of the organic crosslinked polymer particles preferably contains a surfactant for the purpose of preventing re-aggregation of the organic crosslinked polymer particles during the measurement. As the surfactant, both a low molecular surfactant and a high molecular surfactant can be used, but from the viewpoint of preventing aggregation of the organic crosslinked polymer particles, they can be appropriately selected and used. Further, as the type of surfactant, it is more preferable to use an anionic surfactant or a nonionic surfactant from the viewpoint of preventing aggregation of the organic crosslinked polymer particles, and an anionic surfactant is used. Is more preferable. Among them, a sodium polyacrylate surfactant that is a polymer type anionic surfactant can be preferably used. Moreover, what is necessary is just to select suitably content of surfactant contained in the large amount of water used for a measurement in the range of about 50-500 mass ppm.

・ Aluminum oxide fine particles:
The aluminum oxide fine particles used in the present invention include, for example, a pyrolysis method, that is, a method in which anhydrous aluminum chloride is used as a raw material for flame hydrolysis, or an ammonium alum pyrolysis method, that is, aluminum hydroxide is reacted with sulfuric acid as a raw material to produce aluminum sulfate. After that, various methods such as a method of reacting with ammonium sulfate and baking as ammonium alum can be used. The crystal form of aluminum oxide obtained by these methods is preferably α-type, γ-type or δ-type, more preferably γ-type.

  The volume average particle diameter of the aluminum oxide fine particles used in the present invention is preferably 1 μm or less when mixed with ethylene glycol to form a slurry. When the volume average particle diameter exceeds the upper limit, the dispersibility of the organic crosslinked polymer particles tends to deteriorate. On the other hand, the lower limit of the volume average particle diameter of the aluminum oxide fine particles is determined by the production method of the aluminum oxide fine particles, and is usually 0.001 μm or more.

  The volume average particle size of the aluminum oxide fine particles used in the present invention is measured using a centrifugal sedimentation type particle size distribution meter in a state where the ethylene glycol slurry of the aluminum oxide fine particles is diluted with a large amount of water to form an aqueous dispersion, The particle diameter when the volume fraction reaches 50% is defined as the volume average particle diameter. Here, since the aluminum oxide fine particles have good dispersibility in water and hardly re-aggregate at the time of measurement, it is usually not necessary to contain a surfactant in a large amount of water used for measuring the particle size of the aluminum oxide fine particles. However, when reaggregation of the aluminum oxide fine particles occurs during the particle size measurement, it is preferable to contain a surfactant. As the surfactant, both a low molecular surfactant and a high molecular surfactant can be used, but from the viewpoint of preventing aggregation of the aluminum oxide fine particles, they can be appropriately selected and used. Moreover, as a kind of surfactant, it can select from nonionic surfactant or cationic surfactant suitably, and can use it. Further, the content of the surfactant contained in a large amount of water used for the measurement is appropriately selected within a range of about 50 to 500 ppm by mass.

  Further, the volume average particle size of the aluminum oxide fine particles used in the present invention is preferably smaller than the volume average particle size of the organic crosslinked polymer particles, and preferably 1/2 or less of the volume average particle size of the organic crosslinked polymer particles, 1/5 or less is more preferable, and 1/10 or less is particularly preferable. If this ratio is less than the lower limit, the effect of preventing aggregation of the organic crosslinked polymer particles by the aluminum oxide fine particles can be obtained even when the ethylene glycol slurry of the organic crosslinked polymer particles and the ethylene glycol slurry of the aluminum oxide fine particles are mixed and added at the time of polyester production. In other words, the organic cross-linked polymer aggregates in the polyester, and the appearance of the polyester film obtained using the polyester as a raw material may be significantly deteriorated. The lower limit is not particularly limited, but is determined by the lower limit of the volume average particle diameter of the aluminum oxide fine particles.

The specific surface area of the aluminum oxide fine particles used in the present invention is not particularly limited, but from the viewpoint of dispersibility in the polyester, the specific surface area of the inorganic oxide powder in the BET method is preferably 10 to ²⁰⁰ m ² / g, 50 to 150 m ² / g is more preferable.

  The concentration of the organic crosslinked polymer particles in the slurry mixture used in the present invention is preferably 3% by mass or more, more preferably 5% by mass or more, and particularly preferably 10% by mass or more. If the concentration is less than the lower limit, a large amount of slurry mixture may be added, so a large-scale facility may be required. On the other hand, the concentration is preferably 30% by mass or less, more preferably 25% by mass or less, and particularly preferably 20% by mass or less. When the concentration exceeds the upper limit value, the viscosity of the ethylene glycol slurry increases and it may be difficult to add.

  In the preparation of the slurry mixture used in the present invention, it may be obtained by simply mixing the organic crosslinked polymer particles, aluminum oxide fine particles, and ethylene glycol using a stirring blade equipped with a motor. From the viewpoint of dispersibility, it is preferable to obtain a mixture slurry by mixing an ethylene glycol slurry of organic crosslinked polymer particles and an ethylene glycol slurry of aluminum oxide fine particles.

  The method for preparing the ethylene glycol slurry of the organic cross-linked polymer particles or the ethylene glycol slurry of the aluminum oxide fine particles is not particularly limited. For example, ethylene glycol is stirred using a stirring blade equipped with a motor, and the organic cross-linked polymer is mixed therewith. A general method such as charging and mixing particles or aluminum oxide fine particles may be mentioned. In addition, pretreatment such as pulverization, classification, and filtration can be performed as necessary. Furthermore, commercially available surfactants and dispersants can also be used.

  The mixing method of the ethylene glycol slurry of the organic crosslinked polymer and the ethylene glycol slurry of the aluminum oxide fine particles is not particularly limited, and for example, a stirring blade equipped with a motor may be used. Moreover, about the mixing time before addition, it is preferable to mix for 30 minutes or more, More preferably, it is mixing for 60 minutes or more, Especially preferably, it is mixing for 120 minutes or more. Furthermore, it is also preferable to perform pretreatment such as pulverization, classification and filtration as necessary. A commercially available surfactant or dispersant can also be used during the pulverization treatment.

-Addition of organic crosslinked polymer particles:
In the present invention, when the slurry mixture is added in the production process of the organic crosslinked polymer particle polyester, it can be added to any stage of the production process. It is preferable to add between the first-stage reaction tank and the first-stage polycondensation reaction tank.

  The addition amount of the aluminum oxide fine particles with respect to the addition amount of the organic crosslinked polymer particles in the production of the organic crosslinked polymer particle-containing polyester resin composition is preferably 0.1 to 10 times by mass ratio, and is in the range of 0.3 to 5 times. Particularly preferred. If this value is less than the lower limit, the surface of the organic crosslinked polymer particles is not covered with the aluminum oxide fine particles, and thus tends to aggregate in the polyester resin composition. Further, even if this value exceeds the upper limit value, dispersibility is no longer improved any more, and conversely, coarse particles are formed due to aggregation of aluminum oxide fine particles.

Hereinafter, the manufacturing method of the polyester resin composition of this invention is described.
(Polyester raw material)
In the production method of the present invention, a polycondensation reaction is carried out through an esterification reaction and / or a transesterification reaction between a dicarboxylic acid component mainly composed of terephthalic acid or an ester-forming derivative thereof and a diol component mainly composed of ethylene glycol. To obtain a polyester in which 80% or more of the repeating structural units have ethylene terephthalate units.

・ Diol component:
In the present invention, “having ethylene glycol as a main component” means that 80 mol% or more of ethylene glycol is used with respect to all diol components. Of these, ethylene glycol is preferably used in an amount of 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more. When the amount of ethylene glycol used is not more than the lower limit, the strength of the polyester film may be low and the film may not be obtained.

  Examples of diol components other than ethylene glycol used in the present invention include polyether diols such as diethylene glycol, polyethylene glycol, and polytetramethylene ether glycol; trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, and octamethylene glycol. Aliphatic diols such as decamethylene glycol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol; 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol Alicyclic diols such as 1,4-cyclohexane dimethylol and 2,5-norbornane dimethylol; xylylene glycol, 4,4′-dihydroxybiphenyl, 2 2-bis (4′-hydroxyphenyl) propane, 2,2-bis (4′-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid Aromatic diols such as 2,2-bis (4′-hydroxyphenyl) propane ethylene oxide adduct or propylene oxide adduct, and the like. Among these, diethylene glycol and polyethylene glycol can be preferably used. These diol components may be used alone or in combination of two or more.

  In the present invention, the main component of terephthalic acid or an ester-forming derivative thereof (hereinafter sometimes referred to as a terephthalic acid component) is sometimes referred to as a dicarboxylic acid or an ester-forming derivative thereof (hereinafter referred to as a dicarboxylic acid component). ) It means to use 80 mol% or more of terephthalic acid component with respect to the total amount. Among them, the terephthalic acid component is preferably used in an amount of 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more. If the amount of the terephthalic acid component used is less than the lower limit, a polyester having sufficient strength may not be obtained.

  Examples of the ester-forming derivative of terephthalic acid used in the present invention include diesters of alcohols having 1 to 4 carbon atoms. Among them, dimethyl terephthalate and diethyl terephthalate are preferably used.

  Examples of dicarboxylic acid components other than the terephthalic acid component used in the present invention include aromatic dicarboxylic acids such as isophthalic acid and 2,6-naphthalenedicarboxylic acid; alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid; Examples thereof include aliphatic dicarboxylic acids such as acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid, and dodecadicarboxylic acid. These dicarboxylic acid components may be used alone or in combination of two or more.

(Catalyst, auxiliary agent)
In this invention, the catalyst in esterification reaction, transesterification reaction, and polycondensation reaction can be used.

・ Esterification reaction catalyst:
In the esterification reaction, the below-mentioned catalyst and auxiliary agent used at the time of polycondensation can be used. At that time, for example, tertiary amines such as triethylamine, tri-n-butylamine, benzyldimethylamine; quaternary ammonium hydroxides such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide, trimethylbenzylammonium hydroxide, etc. By adding a small amount of a basic compound such as lithium carbonate, sodium carbonate, potassium carbonate or sodium acetate, by-production of diethylene glycol from ethylene glycol can be suppressed.

・ Transesterification catalyst:
Examples of the transesterification reaction catalyst include a long-period periodic table (Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005) (hereinafter sometimes simply referred to as “periodic table”). Group 1A metal element, periodic table 2A group element, manganese And compounds of at least one element selected from the group consisting of iron, and cobalt. Of these, compounds of Group 2A elements of the periodic table, particularly calcium compounds or magnesium compounds, are preferably used because of high transesterification reaction activity and little coloration of the resulting polyester. Further, acetates of calcium or magnesium compounds and hydrates thereof are preferably used because of their good solubility in the reaction system.

・ Polycondensation reaction catalyst:
The polycondensation reaction catalyst is a compound of at least one element selected from the group consisting of aluminum, zinc, gallium, germanium, and antimony, the metal element of Group 1A of the periodic table, the element of Group 2A of the periodic table, manganese, iron And a compound of at least one element selected from the group consisting of cobalt, and a compound of at least one element selected from the group consisting of titanium group elements of Group 4A of the periodic table. Among these, germanium compounds, antimony compounds, and titanium compounds have high polycondensation reaction activity and are preferable. Among these, germanium dioxide, antimony trioxide, and titanium alkoxide are preferably used in terms of handling properties. In addition, although a catalyst is not particularly required for the esterification reaction, the polycondensation reaction catalyst can be added during the esterification reaction.

-Heat stabilization aid:
In the present invention, a phosphorus compound can be added as a heat stabilization aid. Examples of phosphorus compounds include orthophosphoric acid, polyphosphoric acid, and trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl Pentavalent phosphorus compounds such as phosphates such as acid phosphate, and phosphorous acid, hypophosphorous acid, trimethyl phosphite, diethyl phosphite, triethyl phosphite, trisdodecyl phosphite, trisnonyl decyl phosphite , Trivalent phosphorus compounds such as ethyl diethylphosphonoacetate and triphenyl phosphite. Among these, from the viewpoint of controllability of polycondensation rate, phosphoric acid esters of pentavalent phosphorus compounds such as phosphoric acid and phosphoric acid esters are preferable, and trimethyl phosphate and ethyl acid phosphate are particularly preferable.

The addition of the catalyst aid to the reaction system is preferably carried out as a solution of each compound as an alcohol such as ethylene glycol or water.
In the transesterification reaction, the transesterification reaction rate may be reduced, and the phosphorus compound is usually added after the transesterification reaction and before the polycondensation reaction.

(Production of polyester resin composition)
As a method for producing a polyester resin composition applicable to the present invention, a known polyester resin production method is basically used except that an ethylene glycol slurry of organic crosslinked polymer particles is added to a polyester production step with a specific formulation. The production can be carried out either batchwise or continuously. The production method will be described below using polyethylene terephthalate as an example.

・ Raw material preparation process:
After putting the dicarboxylic acid component containing terephthalic acid as the main component and the diol component containing ethylene glycol as the main component together with other copolymerization components, etc., if necessary, into the slurry preparation tank and mixing with stirring The raw material slurry is obtained by filtering as necessary. The molar ratio of the diol component to the dicarboxylic acid component is preferably 1.02 to 2.0, and more preferably 1.03 to 1.7. If the molar ratio is less than the lower limit, the esterification reaction rate will decrease. On the other hand, if the molar ratio exceeds the upper limit, the amount of diethylene glycol produced will increase.

  When the terephthalic acid component is an ester-forming derivative having a melting point without sublimation, such as dimethyl terephthalate, the ester-forming derivative is melted and stored as a raw material, and filtered as necessary separately from ethylene glycol It can be supplied to the esterification step. The molar ratio of ethylene glycol to the ester-forming derivative is preferably 1.5 to 2.5, more preferably 1.7 to 2.3, and particularly preferably 1.9 to 2.1. Is made by If the molar ratio is less than the above range, the transesterification reactivity decreases, whereas if it exceeds the above range, the amount of diethylene glycol produced from ethylene glycol increases.

・ Esterification process:
In the esterification step, an esterification reaction between terephthalic acid and ethylene glycol and / or a transesterification reaction between terephthalic acid ester-forming derivative and ethylene glycol is performed to obtain a polyester low polymer (hereinafter sometimes referred to as an oligomer). It is a process.

  The esterification reaction is carried out by using a multistage reaction apparatus in which a single esterification reaction tank or a plurality of esterification reaction tanks are connected in series, under reflux of ethylene glycol, and water generated in the reaction and excess ethylene. While the glycol is removed from the system, the esterification rate (the ratio of the esterified by reacting with the diol component out of all the carboxyl groups of the raw dicarboxylic acid component) is usually 90% or more, preferably 93% or more Done. Moreover, it is preferable that the number average molecular weight of the oligomer obtained is 500-5,000.

  In the present invention, as the reaction conditions in the esterification reaction, esterification reaction conditions that do not contain organic crosslinked polymer particles or aluminum oxide fine particles may be applied as they are. For example, in the case of a plurality of esterification reaction tanks, the first stage The reaction temperature in the eye esterification reaction tank is usually 240 to 270 ° C., preferably 245 to 265 ° C., and the pressure is usually 0 to 300 kPaG (G indicates a relative pressure with respect to atmospheric pressure), preferably 0 to The reaction temperature in the final stage is usually 250 to 280 ° C, preferably 255 to 275 ° C, and the pressure is usually 0 to 180 kPaG, preferably 0 to 150 kPaG. In the case of using a single esterification reaction tank, the reaction conditions in the final stage are adopted.

  In the case of the transesterification reaction, the transesterification reaction is produced by the reaction under reflux of ethylene glycol using a single transesterification reaction tank or a multistage reaction apparatus in which a plurality of transesterification reaction tanks are connected in series. While removing the ester-derived alcohol component and excess ethylene glycol out of the system, the transesterification reaction rate (ratio of the esterification by reacting with the diol component out of all the carboxyl groups derived from the raw dicarboxylic acid ester component) Usually, it is carried out until it reaches 97% or more, preferably 99% or more. Moreover, it is preferable that the number average molecular weights of the polyester low molecular weight body as a transesterification product obtained are 500-5,000.

  As the reaction conditions in the transesterification reaction, the transesterification reaction conditions that do not include organic crosslinked polymer particles or aluminum oxide fine particles may be applied as they are. For example, in the case of a plurality of transesterification reaction tanks, the first stage transesterification The reaction temperature in the reaction vessel is usually 180 to 230 ° C., preferably 180 to 220 ° C., the pressure is usually 0 to 300 kPaG, preferably 0 to 200 kPaG, and the reaction temperature in the final stage is usually 220 to 260 ° C., preferably 225-240 degreeC and a pressure can be 0-200 kPaG normally, Preferably it is 0-150 kPaG. When the reaction is carried out in a single transesterification reactor, the transesterification is carried out at a reaction temperature of 150 to 280 ° C., preferably 150 to 250 ° C. and a pressure of 0 to 200 kPaG, preferably 0 to 150 kPaG. Perform the reaction.

  In the present invention, when a transesterification method using a terephthalic acid derivative is used as the terephthalic acid component, the viscosity of the polyester oligomer is lowered, so that the dispersibility of the organic crosslinked polymer particles is improved when the slurry mixture is added. Therefore, it is preferable. Among them, it is preferable to use a transesterification method using dimethyl terephthalate. In particular, when the slurry mixture is added immediately before the polycondensation reaction, the effect is remarkable.

  When adding the slurry mixture to any stage of the production process of the polyester resin composition of the present invention, in the batch method, it may be charged all at once into the reaction vessel, or may be added continuously through piping or the like. Good. Moreover, in a continuous method, you may add through piping etc. to reaction tanks, such as an esterification tank and a polycondensation reaction tank, and you may inject | pour into the piping which connects a reaction tank. Furthermore, when adding to a reaction vessel or reaction vessel having a gas-liquid interface, the slurry mixture may be added to the gas phase portion or the liquid phase portion, but the slurry mixture is added to the inner wall surface of the vessel. It is preferable to prevent the particles from adhering to dryness and becoming an aggregate of organic crosslinked polymer particles to be mixed into the polyester resin composition.

・ Polycondensation process:
In the present invention, a polycondensation step is performed following the esterification / transesterification step. The melt polycondensation may be either a continuous type or a batch type, but in the case of the continuous type, a plurality of melt polycondensation tanks are connected in series. For example, the first stage is equipped with a stirring blade and is completely mixed Type ethylene glycol produced as a by-product was distilled out of the system under reduced pressure using a multistage reactor consisting of a horizontal type plug flow type reactor equipped with a stirrer blade in the second and third stages. To be done.

  As reaction conditions in continuous melt polycondensation, continuous melt polycondensation reaction conditions that do not include organic crosslinked polymer particles or aluminum oxide fine particles may be applied as they are. For example, in the case of a plurality of polycondensation tanks, The reaction temperature in the first stage polycondensation tank is usually 250 to 290 ° C., preferably 260 to 280 ° C., the absolute pressure is usually 65 to 1.3 kPa, preferably 26 to 2 kPa, and the reaction temperature in the final stage is Usually, 265 to 300 ° C., preferably 270 to 295 ° C., and the absolute pressure is usually 1.3 to 0.013 kPa, preferably 0.65 to 0.065 kPa. As reaction conditions in the intermediate stage, those intermediate conditions are selected. For example, in a three-stage reactor, the reaction temperature in the second stage is usually 265 to 295 ° C., preferably 270 to 285 ° C., and the absolute pressure is Usually, it is 6.5 to 0.13 kPa, preferably 4 to 0.26 kPa.

  On the other hand, in the case of a batch type, batch-type melt polycondensation reaction conditions that do not contain organic crosslinked polymer particles or aluminum oxide fine particles may be applied as they are, and are usually connected in series with an esterification or transesterification reaction tank. Using a reaction apparatus comprising a polycondensation reaction tank, ethylene glycol produced as a by-product is distilled out of the system under reduced pressure.

  As reaction conditions in batch-type melt polycondensation, for example, the reaction temperature in the melt polycondensation tank is usually gradually raised in the range of 220 to 300 ° C., preferably 220 to 295 ° C., gradually reduced, and the final pressure is usually reduced. 1.3 to 0.013 kPa, preferably 0.65 to 0.065 kPa.

・ Pelletization, solid phase polycondensation:
Resin obtained by melt polycondensation is usually extracted in the form of a strand from the outlet provided at the bottom of the polycondensation tank, and is cooled with water or after cooling with water and then cut with a cutter to form particles such as pellets and chips. The polyester resin composition is in the form of a sheet. The obtained polyester resin composition may be subjected to solid phase polycondensation under an inert gas atmosphere or reduced pressure below the melting point as necessary.

EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded. In addition, when it has "the polyester resin part", the mass of polyester contained in a polyester resin composition is shown.
Each characteristic value of the polyester and polyester film used in the present invention was measured according to the following method.

(Intrinsic viscosity of polyester (IV) [dL / g])
The measurement was performed at 30 ° C. using a mixed solution of 1,1,2,2-tetrachloroethane / phenol = 1/1 (mass ratio) as a solvent.
After dissolving about 0.25 g of a polyester resin sample in about 25 mL of a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (mass ratio 1/1) to a concentration of 1.00 g / dL , Cooled to 30 ° C., and at 30 ° C., measured the number of seconds of dropping of the sample solution and the solvent alone with a fully automatic solution viscometer (“DT553” manufactured by Sentec Co., Ltd.). Was calculated.
IV = ((1 + 4K _H η _sp ) ^0.5 −1) / (2K _H C)
Here, η _sp = η / η ₀ −1, η is the sample solution drop time, η ₀ is the solvent drop time, C is the sample solution concentration (g / dL), and K _H is Huggins It is a constant. K _H adopted the 0.33. The sample is dissolved at 110 ° C. for 30 minutes.

(Measurement of volume average particle diameter of organic crosslinked polymer particles contained in ethylene glycol slurry of organic crosslinked polymer particles [μm])
0.03 to 0.10 g of ethylene glycol slurry of organic crosslinked polymer particles is mixed with 200 ml of an aqueous solution of a polyacrylic acid dispersant (trade name: Aron T-50, manufactured by Toa Gosei Co., Ltd.) to obtain a laser diffraction particle size distribution. The volume average particle diameter was measured using a meter (trade name: MT-3000II, manufactured by Nikkiso Co., Ltd.). The volume average particle size in this case is the particle size when the volume fraction reaches 50%. An aqueous solution of Aron T-50 was obtained by adding 0.01 parts by mass of Aron T-50 (concentration: 43% by mass) to 100 parts by mass of water and mixing them sufficiently.

(Measurement of volume average particle size of aluminum oxide fine particles contained in ethylene glycol slurry of aluminum oxide fine particles [μm])
1 g of ethylene glycol slurry of aluminum oxide fine particles was mixed with 50 g of pure water, and the volume average particle size was measured using a centrifugal sedimentation type particle size distribution meter (trade name: SACP-4L, manufactured by Shimadzu Corporation). The volume average particle size in this case is the particle size when the volume fraction reaches 50%.

(Evaluation of film appearance)
The appearance of the film was visually evaluated. When the aggregate was not confirmed visually, it was judged as “good”, and when the aggregate was confirmed visually, it was judged as “bad”.

(Confirmation of organic cross-linked polymer particle aggregates contained in polyester film)
After a 15 μm thick polyester film was formed into a 1.5 cm × 0.8 cm slice, aluminum was evaporated and 160 times magnification (eyepiece magnification was 16 times and objective lens magnification was 10 using a differential interference microscope). 20 times) of 0.7 mm × 0.825 mm fields of view, and the presence or absence of aggregates of organic crosslinked polymer particles having a size in the film plane direction of 20 μm or more in all 20 fields of view was confirmed.

(Film friction test)
Two films obtained in the examples are overlapped, and the two films are rubbed by hand 30 times while applying as little load as possible. The surface state is visually judged, and if there are scratches or defects, "bad" If there were no scratches or defects, it was judged as “good”.

(Production of ethylene glycol slurry of aluminum oxide fine particles)
100 parts by mass of ethylene glycol, polymer dispersant (polyethyleneimine alkylene oxide adduct, trade name: DISCOL E420, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 0.003 parts by mass, 0.02 part by mass of pure water were weighed, 22 parts by mass of aluminum oxide fine particles (hydrophilic fumed alumina, primary particle size: 13 nm, trade name: Aluminum Oxide C, manufactured by Nippon Aerosil Co., Ltd.) were added and mixed with a stirrer to obtain an ethylene glycol slurry of aluminum oxide fine particles. Next, the aluminum oxide fine particles were pulverized by a horizontal continuous wet medium stirring mill (trade name: Dino Mill, manufactured by Shinmaru Enterprises Co., Ltd.) so that the average particle diameter of the aluminum oxide fine particles was 0.07 μm. Next, after performing a centrifugal separation process with a cylindrical centrifuge (ASM160, manufactured by Sakai Kogyo Co., Ltd.), an average particle size of 0.07 μm is obtained by filtering with a cartridge filter (trade name: SL-030, manufactured by Loki Techno Co., Ltd.). An ethylene glycol slurry of aluminum oxide fine particles was obtained.

(Production of crosslinked polystyrene particles)
After adding 3.2 parts by weight of potassium persulfate as a water-soluble polymerization initiator and 0.15 parts by weight of sodium lauryl sulfate as a dispersion stabilizer to 1500 parts by weight of demineralized water and uniformly dissolving, 92 parts by weight of styrene and divinylbenzene 8 parts by mass of the mixed solution was added. While stirring in a nitrogen gas atmosphere, the polymerization reaction was performed at 70 ° C. for 24 hours. When the obtained particles were observed with an electron microscope, they were almost spherical with an average particle size of 1.0 μm. The slurry after the polymerization reaction was spray-dried to obtain powdered crosslinked polystyrene particles.

(Production of crosslinked polystyrene particle ethylene glycol slurry)
10 parts by mass of the crosslinked polystyrene particles obtained above and 90 parts by mass of ethylene glycol were weighed and mixed with a stirrer, and then filtered through a cartridge filter (trade name: SLS-150, manufactured by Loki Techno Co., Ltd.). An ethylene glycol slurry was obtained. The average particle size of the crosslinked polystyrene particles in the slurry measured with a laser diffraction particle size distribution meter was 1.0 μm, and the particle concentration was 10% by mass.

(Production of cross-linked polymethyl methacrylate particles)
After adding 3.2 parts by weight of potassium persulfate as a water-soluble polymerization initiator and 0.15 parts by weight of sodium lauryl sulfate as a dispersion stabilizer to 1500 parts by weight of demineralized water and uniformly dissolving, 63 parts by weight of methyl methacrylate, A mixed solution of 37 parts by mass of divinylbenzene was added. While stirring in a nitrogen gas atmosphere, the polymerization reaction was performed at 70 ° C. for 24 hours. When the obtained particles were observed with an electron microscope, they were almost spherical. The slurry after the polymerization reaction was spray-dried to obtain powdered crosslinked polystyrene particles. When the particle size distribution of the obtained particles was measured, 90% by mass or more was 250 to 850 μm.

(Method for measuring particle size distribution of crosslinked polymethyl methacrylate particles)
About 3 g of the sample was weighed, about 0.06 g of white carbon (hydrous silicate) was put therein, and disposable polyethylene gloves were used, and the sample surface was thoroughly sprinkled to remove adhering moisture on the sample surface. Next, the sample coated with the white carbon is JIS standard sieve (850 μm, 850 μm, set by sequentially superposing on a sonic vibration type automatic sieve division particle size distribution measuring instrument (trade name: Robot Shifter RPS-85, manufactured by Seishin Enterprise Co., Ltd.). 710 μm, 500 μm, 300 μm, 250 μm, 212 μm). Next, the operating condition of the robot shifter was set to an amplitude intensity of 7 to 9, and sieved for 5 minutes (operation and rest were alternately performed at 1 second intervals).
Note that the mass of the particles on each sieve is automatically measured. Moreover, since the particle size of white carbon is 212 μm or less, it does not remain on the sieve.
The particle size distribution of 250 to 850 mμ is obtained by dividing the sum of the masses of particles remaining on each of the five sieves excluding 212 μm by the charged particle mass.

(Production of crosslinked polymethyl methacrylate particle ethylene glycol slurry)
The crosslinked polymethylmethacrylic acid particles obtained above are subjected to a dry pulverization treatment with a dry pulverizer (trade name: Ultramizer ASK-2, manufactured by Fuji Powder Co., Ltd.), and an amorphous crosslinked polymethacrylic compound having an average particle size of 2.0 μm. Methyl acid particles were obtained. Next, 100 parts by mass of ethylene glycol and 0.18 parts by mass of a polymeric dispersant (special ammonium polycarboxylate, trade name: DISCOAT N14, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were placed in a reactor and subjected to dry pulverization treatment. Ethylene glycol slurry of crosslinked polymethyl methacrylate particles was obtained by adding 11 parts by mass of methyl acid particles and mixing with a stirrer. Next, a wet crushing process was performed with a horizontal continuous wet medium stirring mill (trade name: Dino Mill, manufactured by Shinmaru Enterprises Co., Ltd.) so that the average particle diameter of the crosslinked polymethylmethacrylate particles was 0.3 μm, and then a cylindrical centrifugal Centrifugation is performed with a separator (trade name: ASM160, manufactured by Sakai Kogyo Co., Ltd.), and filtered through a cartridge filter (trade name: SL-150, manufactured by Loki Techno Co.) to obtain an ethylene glycol slurry of crosslinked polymethylmethacrylic acid particles. It was. The average particle diameter of the crosslinked polymethyl methacrylate particles in the slurry was 0.3 μm, and the particle concentration was 6% by mass.

(Mixing of each ethylene glycol slurry of organic polymer particles and aluminum oxide particles)
An ethylene glycol slurry of organic crosslinked polymer particles and an ethylene glycol slurry of finely divided aluminum oxide fine particles were mixed for 120 minutes using a stirring blade and a motor.

(Production of polyethylene terephthalate resin that does not contain organic crosslinked polymer particles)
A slurry is prepared by using a continuous polymerization apparatus comprising a slurry preparation tank, a two-stage esterification reaction tank connected in series to the slurry preparation tank, and a three-stage melt polycondensation tank connected in series to the second-stage esterification reaction tank. To the preparation tank, terephthalic acid and ethylene glycol were continuously supplied at a mass ratio of 865: 485, and a 0.3 mass% ethylene glycol solution of ethyl acid phosphate was added to the produced polyester resin with phosphorus atoms (P ) Is continuously added in an amount of 23 ppm by mass, and a slurry is prepared by stirring and mixing. The slurry is 260 ° C. under a nitrogen atmosphere, a pressure of 50 kPaG, and an average residence time of 4 hours. The first stage esterification reaction tank set to, then the second set to 260 ° C., 5 kPaG, average residence time 1.5 hours under nitrogen atmosphere And continuously transferred to the esterification reactor stage and reacted esterification.

  Subsequently, when the esterification reaction product obtained above is transferred to a melt polycondensation tank, a 0.2 mass% ethylene glycol solution of magnesium acetate tetrahydrate is added to the transfer polyester with magnesium for the produced polyester. After continuously adding in an amount such that the content as atoms (Mg) is 31 mass ppm, a 0.3 mass% ethylene glycol solution of antimony trioxide is contained as antimony atoms (Sb) in the produced polyester resin. The amount was continuously added so as to be 233 mass ppm. Next, the first stage melt polycondensation tank set at 270 ° C., pressure 2.6 kPa, and average residence time 1.2 hours, and then set at 278 ° C., 0.5 kPa, and average residence time 1.2 hours. The second stage melt polycondensation tank, and then continuously transferred to the third stage melt polycondensation tank set at 280 ° C., pressure 0.3 kPa, and average residence time 1.2 hours to melt The polyester resin was subjected to polycondensation, extracted in a strand form from an extraction port provided at the bottom of the polycondensation tank, water-cooled, and then cut with a cutter to produce a polyester resin having chip-like granules having a number average particle weight of 24 mg. The intrinsic viscosity of the obtained resin was 0.60 dL / g.

  In the following examples, the organic cross-linked polymer particles and the aluminum oxide fine particles were added as an ethylene glycol slurry, but the described addition amount is the addition amount of the compound as a solid content.

Example 1:
100 parts by mass of dimethyl terephthalate and 65 parts by mass of ethylene glycol were charged into a transesterification reactor equipped with a stirrer, a temperature raising device and a distillate separation column, and heated to 150 ° C. to melt dimethyl terephthalate. Next, after adding an ethylene glycol solution of magnesium acetate tetrahydrate so that 0.09 parts by mass of magnesium acetate is added to the resulting polyester composition, the temperature is raised to 225 ° C. over 3 hours under normal pressure. Further, the mixture was stirred and held at 225 ° C. for 1 hour and 15 minutes, and transesterification was carried out while distilling off methanol. The transesterification reaction was substantially terminated to obtain a polyester low polymer (oligomer).

  Next, after the polyester oligomer is transferred to a polycondensation reaction tank equipped with a stirrer, a temperature raising device, and a pressure reduction device, 1.0 mass% of crosslinked polystyrene particles with stirring is obtained based on the obtained polyester, and aluminum oxide fine particles Was added in advance to the oligomer so that 0.50% by mass of the obtained polyester was added to the oligomer.

  Next, an ethylene glycol solution of phosphoric acid as a heat stabilizer and an ethylene glycol solution of antimony trioxide as a polycondensation catalyst were added so that the amount of phosphoric acid added was 0.03% by mass with respect to the obtained polyester. After adding to the oligomer such that the antimony addition amount is 0.04% by mass with respect to the obtained polyester, the pressure is reduced from 101.3 kPa to 0.4 kPa in 85 minutes and maintained at 0.4 kPa, and from 225 ° C. The temperature was raised to 280 ° C. over 2 hours and held at 280 ° C. for 1.5 hours to conduct a polycondensation reaction, thereby obtaining a polyester composition having an intrinsic viscosity of 0.62 dL / g measured as a composition.

  Next, the polyester composition and a polyethylene terephthalate resin not containing crosslinked polystyrene particles are mixed in a hopper of a polyester film molding machine so that the amount of crosslinked polystyrene particles contained in the polyester film is 0.3% by mass, and then 285. After obtaining an unstretched sheet by melt-extrusion molding at 90 ° C., it is successively biaxially stretched 4.0 times in the longitudinal direction and then 3.5 times in the transverse direction at 90 ° C., and then heat-set at 180 ° C. for 3 minutes. Thus, a biaxially stretched polyester film having a thickness of 15 μm was obtained. When the obtained polyester film was observed with a differential interference microscope, it was confirmed that there were no aggregates of organic crosslinked polymer particles of 20 μm or more as shown in FIG. Table 1 shows the characteristics of the polyester film. There were no aggregates of organic crosslinked polymer particles that could be visually confirmed, and the appearance of the polyester film was good.

Example 2:
In Example 1, the polyester composition and the polyester film were obtained in the same manner as in Example 1 except that the addition amount of the crosslinked polystyrene particles and the aluminum oxide fine particles to the obtained polyester resin composition was changed as shown in Table 1. It was. The obtained polyester film had 0 aggregates of organic crosslinked polymer particles of 20 μm or more. Further, there was no aggregate of organic crosslinked polymer particles that could be visually confirmed, and the appearance of the polyester film was good.

Example 3:
In Example 1, 0.02% by mass of tetra-n-butyl-titanate was used as a polyester polycondensation catalyst instead of antimony trioxide, and the addition amounts of organic crosslinked polymer particles and aluminum oxide fine particles were changed as shown in Table 1. A polyester composition and a polyester film were obtained in the same manner as in Example 1. The obtained polyester film had 0 aggregates of organic crosslinked polymer particles of 20 μm or more. Further, there was no aggregate of organic crosslinked polymer particles that could be visually confirmed, and the appearance of the polyester film was good.

Example 4:
In Example 1, instead of the cross-linked polystyrene particles, a mixed slurry of cross-linked polymethyl methacrylate particles having a volume average particle size of 0.3 μm subjected to a wet pulverization treatment and aluminum oxide fine particles, and organic cross-linked polymer particles A polyester composition and a polyester film were obtained in the same manner as in Example 1 except that the addition amount of the aluminum oxide fine particles was changed as shown in Table 1. The obtained polyester film had 0 aggregates of organic crosslinked polymer particles of 20 μm or more. Further, there was no aggregate of organic crosslinked polymer particles that could be visually confirmed, and the appearance of the polyester film was good.

Comparative Example 1:
In Example 2, a polyester composition and a polyester film were obtained in the same manner as in Example 2 except that the ethylene glycol slurry of aluminum oxide fine particles was not added (that is, the crosslinked polystyrene particles were added alone). As shown in FIG. 2, a large number of aggregates of 20 μm or more were confirmed. Many agglomerates having a size of 100 μm or more were also confirmed. Table 1 shows the characteristics of the polyester film. The appearance was poor because there were many aggregates of organic crosslinked polymer particles that could be visually confirmed.

Comparative Example 2:
In Example 2, a polyester composition and a polyester film were obtained in the same manner as in Example 2 except that the ethylene glycol slurry of crosslinked polystyrene particles and the ethylene glycol slurry of aluminum oxide fine particles were added separately. In the obtained polyester film, many aggregates of polystyrene particles were confirmed as shown in FIG. 3, and many aggregates of 20 μm or more were confirmed. Many agglomerates having a size of 100 μm were also confirmed. Table 1 shows the characteristics of the polyester film. The appearance was poor because there were many aggregates of organic crosslinked polymer particles that could be visually confirmed.

As shown in Table 1, the polyester compositions of Examples 1 to 4 obtained by adding a mixture of an ethylene glycol slurry of organic crosslinked polymer particles and an ethylene glycol slurry of aluminum oxide fine particles to a polyester oligomer and performing a polycondensation reaction are as follows. Aggregates of 20 μm or more were not observed, and it was confirmed that the crosslinked polymer particles were dispersed and the film surface was uneven. Moreover, the polyester film obtained from the polyester composition had no appearance of aggregates of organic crosslinked polymer particles that could be visually confirmed, and had a good appearance.
On the other hand, in the polyester composition of Comparative Example 1 produced using only organic crosslinked polymer particles without using aluminum oxide fine particles, many aggregates of 20 μm or more were observed, and the dispersibility of the organic crosslinked polymer particles was high. It was bad. In addition, the polyester film obtained from the polyester composition had many appearances of aggregates of organic crosslinked polymer particles that could be visually confirmed, and had a poor appearance.
In addition, the polyester composition of Comparative Example 2 obtained by polycondensation reaction without adding the ethylene glycol slurry of organic crosslinked polymer particles and the ethylene glycol slurry of aluminum oxide fine particles separately to the polyester oligomer was 20 μm. Many of the above aggregates were observed, and the dispersibility of the organic crosslinked polymer particles was poor. Further, the polyester film obtained from the polyester composition had a poor appearance due to the presence of a large number of aggregates of organic crosslinked polymer particles that could be visually confirmed. Furthermore, when the polyester films of the comparative example were overlapped and rubbed 30 times, the surface of the polyester film was scratched. However, even when the polyester film of the example was evaluated in the same manner, the surface was not scratched.

  According to the present invention, the dispersibility in the polyester of the organic crosslinked polymer particles that easily aggregate is improved, and the polyester film produced from the polyester composition obtained by the production method of the present invention has a good appearance and good The organic cross-linked polymer particles dispersed in the film reduce the friction coefficient of the polyester film and improve the wear characteristics. Among them, the transparency of the film is not impaired, and aggregates of 20 μm or more are not confirmed, so that it is particularly useful as an optical film.

Claims (6)

An esterification step of obtaining a polyester low polymer by performing esterification reaction and / or transesterification reaction of a dicarboxylic acid component mainly composed of terephthalic acid or an ester-forming derivative thereof and a diol component mainly composed of ethylene glycol. In a method for producing an organic crosslinked polymer particle-containing polyester having a polycondensation step in which a polyester is obtained by polycondensation of the obtained polyester low polymer, an ethylene glycol slurry of fine aluminum oxide particles and an ethylene glycol slurry containing organic crosslinked polymer particles, An ethylene glycol slurry containing both organic crosslinked polymer particles and aluminum oxide fine particles (provided that the ratio of the volume average particle size of the aluminum oxide fine particles to the volume average particle size of the organic crosslinked polymer particles is 1 / 4.3 or less) organic crosslinking Process for producing a polyester resin composition characterized by adding to any stage of molecular particles containing polyester manufacturing process. The production method according to claim 1 , wherein the ester-forming derivative is dimethyl terephthalate. The volume average particle diameter of the organic crosslinked polymer particles is 0.01 to 3 μm, and the production method according to claim 1 or 2 . The production method according to any one of claims 1 to 3 , wherein the addition amount of the organic crosslinked polymer particles is 0.1 to 3.0 mass% with respect to the polyester. The production method according to any one of claims 1 to 4 , wherein the volume average particle diameter of the aluminum oxide fine particles is 0.001 to 1 µm. The production method according to any one of claims 1 to 5 , wherein the addition amount of the aluminum oxide fine particles with respect to the addition amount of the organic crosslinked polymer particles is 0.1 to 10 times by mass ratio.

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