JP4880906B2 - Polyester resin composition for film and method for producing polyester film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for production of a silica particle glycol slurry for addition to a polyester by good productive cracking of coarse silica particles with excellent transparency without inducing troubles such as re-aggregation and a process for production of a polyester resin composition and a film without inducing troubles such as re-aggregation by an effective and highly uniform particle dispersion of highly transparent silica particles. <P>SOLUTION: The process for production of the silica particle glycol slurry for a polyester comprises placing the glycol slurry containing silica particles with a specific surface area of 150-450 m<SP>2</SP>/g and an average particle size of 2.0-4.0 &mu;m under high pressure of 50-250 MPa followed by release from opposing nozzles so as to collide the glycol slurries and filtration. In addition, the process for the production of the polyester resin composition and the film is provided. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

The present invention relates to a silica particle glycol slurry for polyester containing a silica particle having a specific surface area of 150 to 450 m ² / g and an average particle diameter of 2.0 to 4.0 μm, a polyester resin composition, and a method for producing a polyester film. It is.

  Since silica particles have a relatively close refractive index to polyester resins typified by polyethylene terephthalate and polyethylene naphthalate, they are frequently used for film applications that require high transparency. Silica particles are mainly divided into particles synthesized by a dry method and a wet method. The former includes fumed silica which is an aggregate of silica particles having a primary particle diameter of several tens of nanometers synthesized by baking a liquid Si compound at a high temperature. On the other hand, the latter is also called gel method silica, and examples thereof include light anhydrous silicic acid produced by reacting sodium silicate in an acidic aqueous solution, pulverizing it through washing with water and drying, and depending on the case, dry classification. (For example, refer to Japanese Patent Application Laid-Open No. 2004-175902.)

  By the way, silica particles are preferably particles having a small primary particle diameter and a large specific surface area for use in films and sheets for optical use and packaging that require a high degree of transparency. Since such particles have a large specific surface area, they possess a flexible particle shape that can follow the stretching stress received when the polyester resin composition containing the particles is processed into a film or sheet. Commonly used particles with a small specific surface area tend to form during stretching, and voids around the particles, called voids, are unlikely to occur, and as a result, the light that passes through the film is difficult to scatter, resulting in a highly transparent film This is because it can be applied to a sheet. On the other hand, for optical use, for example, DFR (Dry Photo Film Resist) has not only been excellent in transparency but also required to reduce coarse particles including aggregated particles. In addition, it can be said that the smaller the primary particle diameter and the larger the specific surface area, the easier it is to aggregate, and the improvement in transparency and the reduction of coarse particles are in a contradictory relationship.

In order to suppress the incorporation of such coarse particles, a method of producing a polyester resin in addition to the polyester synthesis reaction system after performing operations such as dispersion slurrying, pulverization (pulverization), classification, and filtration of the particles. It is common. As a specific crushing process, wet crushing (or crushing) processes such as a sand mill and a ball mill are generally used. However, in these processes, the medium remains or causes coloring or the like during the processing. Or problems such as re-aggregation due to overgrinding. Patent Document 1 proposes a method for removing coarse particles by a centrifugal separator. However, these methods have problems such as requiring a lot of time and labor for unit operation. Therefore, the present condition is that the manufacturing method of the glycol slurry, the polyester resin composition, and the polyester film containing the silica particle which has transparency improvement and the reduction | decrease of a coarse particle simultaneously is not yet provided.
JP 2004-175902 A

  An object of the present invention is to solve the above-mentioned problems and to add silica particles glycol for addition to a polyester that pulverizes coarse particles with high productivity without causing problems such as re-aggregation of silica particles having excellent transparency. It is to provide a method for producing a slurry. Another object of the present invention is to provide a polyester resin composition in which silica particles having excellent transparency can be dispersed in polyester without causing problems such as re-aggregation with a highly uniform particle size distribution. And providing a method for producing a polyester film.

  As a result of diligent research on a method for producing a polyester resin composition in order to solve the above-described problems, the present inventors conducted bidirectional bifurcation of a slurry at a specific ultrahigh pressure state in a purification stage of the slurry before being added to the polyester synthesis reaction system. When the particles are released from each other and collided with each other, the particle size distribution of the primary particles originally owned by the particles themselves can be realized in a short time while suppressing the generation of agglomerated particles, and the filterability is also greatly improved for further filtration. It has been found that a glycol slurry containing silica particles with greatly reduced agglomerated particles and coarse particles can be efficiently produced, and the glycol slurry thus obtained is used. Therefore, the same effects can be obtained in the polyester resin composition and the film or sheet obtained by processing the resin composition. Also it found that it was arrived at the present invention.

Thus, according to the present invention, a glycol slurry containing silica particles having a specific surface area of 150 to 450 m ² / g and an average particle diameter of 2.0 to 4.0 μm is brought into a high pressure state of 50 to 250 MPa, and then the nozzle facing each other. the glycol was released as the slurry collide with each other from glycols particles consisting of light anhydrous silicic acid in the slurry was disintegrated, then the absolute filtering accuracy 10μm polyester for silica particles glycol slurry is filtered through a smaller filter, polyester reaction There is provided a method for producing a polyester resin composition for a film comprising a step of adding to a system and conducting a polymerization reaction .

Further, according to the present invention, a method of manufacturing a polyester film for molded into a film by melt extrusion of the port Riesuteru resin composition of the present invention into a sheet it is also provided.

  Moreover, the glycol slurry of this invention, the polyester resin composition, and the manufacturing method of a polyester film WHEREIN: As a preferable aspect, a silica particle is a particle | grains which consist of light anhydrous silicic acid, and a high-pressure state is the pressure of 50-150 Mpa, and crushing The treatment was repeated twice or more. In the filtered glycol slurry, the ratio of particles having a particle size of 5 μm or more was 0.5% by mass or less when the volume of all particles was used as a reference. In the glycol slurry, the ratio of particles having a particle diameter of 2 μm or less is 2.0% by mass or less, and the polyester resin is polyethylene terephthalate or polyethylene-2,6-naphthalate, based on the volume of all particles. Including at least one of the above.

  According to the present invention, in the purification stage of the slurry before being added to the polyester synthesis reaction system, the slurry is injected from both directions in a specific ultrahigh pressure state, and the generation of aggregated particles is suppressed by colliding the particles, The particles can be crushed in a short time to close to the particle size distribution of the primary particles originally owned, and the generation of coarse particles is suppressed, so the filterability is greatly improved and filtration with a finer filter is also possible. As a result, a glycol slurry containing silica particles with greatly reduced aggregated and coarse particles is obtained. And the coarse particle | grains, such as an aggregated particle, can be suppressed in the film and sheet-like thing obtained by processing a polyester resin composition and this resin composition by using the glycol slurry disintegrated uniformly in this way.

First, the manufacturing method of the glycol slurry of this invention is demonstrated. As a method for producing the glycol slurry of the present invention, a method known per se can be suitably employed, but a glycol containing silica particles having a specific surface area of 150 to 450 m ² / g and an average particle size of 2.0 to 4.0 μm. After the slurry is brought to a high pressure state of 50 to 250 MPa, the glycol slurry discharged from the nozzles facing each other is discharged so as to collide with each other, and the silica particles are crushed and then filtered. It is.

The silica particles used in the present invention have a BET specific surface area of 150 to 450 m ² / g, preferably 200 to 350 m ² / g. If the specific surface area is too small, the stretchability of the particles deteriorates and voids are generated around the particles, resulting in a decrease in transparency in the film. Conversely, if the surface area is too large, reaggregation tends to proceed during the polyester production reaction. The tendency for the aggregated particles in the resin composition to increase cannot be suppressed.

The average particle size of the silica particles is 2.0 to 4.0 μm, preferably the average particle size (also referred to as volume-based integrated 50% particle size: d50) measured with a laser light scattering particle size distribution analyzer. Is 2.0 to 3.5 μm. If the particle size is too small, reaggregation cannot be prevented, and if it is too large, removal of coarse particles becomes difficult.
The silica particles used in the present invention are preferably particles made of light anhydrous silicic acid because they can easily synthesize particles having a small primary particle size and a large specific surface area.

  One of the features of the present invention lies in the slurry refining process. Silica particles dispersed in glycol by a conventional method such as a mixer and slurried are collided with glycol slurries released from 50 to 250 Mpa and facing nozzles. And the silica particles are crushed by collision of the particles in the glycol slurry. The higher the pressure, the greater the pulverization effect, but it is necessary to make the device more robust, or the process proceeds from pulverization to pulverization and the number of pulverized fine particles increases, and these reaggregate. As a result, coarse particles are formed. On the other hand, if the pressure is too low, a sufficient crushing effect cannot be obtained, or a long time is required for crushing.

  As preferable processing conditions in the present invention, from the viewpoint of shortening the processing time, it is preferable to perform a single crushing process at a pressure of 120 to 250 MPa, further 160 to 250 MPa, and particularly 180 to 250 MPa. By setting it to such a pressure range, it is possible to perform crushing to a high degree even by a single crushing process. On the other hand, from the viewpoint of stably carrying out industrially uniform crushing, it is repeated at a pressure of 50 to 150 MPa, further 60 to 120 MPa, particularly 80 to 100 MPa, equivalent to 2 passes or more, and further 2 to 5 passes. Is preferred. By performing the treatment multiple times at such a pressure, it is possible to suppress an increase in fine particles due to the pulverization of the particles. Moreover, the number of passes required to obtain a desired particle size distribution can be reduced by setting the processing pressure to the lower limit or higher. The repeated treatment method may be a self-circulation method with the same liquid filled in the container, or a batch treatment method that is divided and repeated. The former method is excellent in operability, and the latter method does not have a short path and realizes reliable processing in terms of quality.

  The glycol slurry thus treated can be easily filtered with a filter having a small opening, which has been difficult to achieve by wet crushing (or pulverization) processing represented by a sand mill or a ball mill, and agglomerated particles remaining in the slurry. Can now be removed. Specifically, the slurry that has not been subjected to the crushing treatment used in the present invention, for example, when filtering with a filter having an absolute filtration accuracy of 10 μm or less, the filtration pressure suddenly increases and cannot be filtered. Will be required. In this respect, the above-described crushing treatment and filtration treatment are not merely an additional combination, but are organically combined with each other. In addition, the absolute filtration precision here means the particle diameter in which 99.98% or more of particles are supplemented. The lower limit of the absolute filtration accuracy of the filter is not particularly limited as long as the process is not destabilized due to clogging of the filter, but is preferably 1.5 times the average particle diameter or more, and the upper limit is 10 μm. The following is preferable.

  In the glycol slurry thus purified, the ratio of particles having a particle size of 5 μm or more in the volume-based particle size distribution (the value obtained by subtracting the accumulated ratio of particles of 5 μm or less from 100%) is preferably 2% or less. More preferably, it is 1.5% or less, particularly preferably 1.0% or less. By adding such a slurry to the polyester reaction system, the desired polyester resin composition with few coarse particles and aggregated particles can be obtained.

  In addition, in the glycol slurry thus purified, the ratio of particles having a particle size of 1.5 μm or less in the volume-based particle size distribution is preferably 20% or less, more preferably 17% or less, particularly 15%. preferable. A polyester resin composition containing a small amount of aggregated particles containing a polyester resin composition produced by adding the slurry to a polyester reaction system by reducing the proportion of particles having a particle size of 1.5 μm or less. It can be. Such a ratio can be achieved, for example, by adjusting so as to process a plurality of times under the above-mentioned relatively mild conditions so as not to cause pulverization of particles.

  The concentration of the slurry in the process from the start of slurry preparation to the addition to the polyester synthesis reaction system in the present invention is preferably 5 to 20% by weight in consideration of handleability and dispersibility. Of course, various compounds typified by alkali metal salts or hydroxides may be added to the glycol slurry as a dispersant.

Below, the manufacturing method of the polyester resin composition of this invention is demonstrated.
In the present invention, the addition timing of the glycol slurry prepared by the above-described method to the polyester production reaction is not particularly limited, and from the start of the esterification reaction or transesterification reaction until the reaction is completed and transferred to the polymerization kettle. What is necessary is just to add, and what is necessary is just to add in the normal temperature range which esterification or transesterification reaction is complete | finished. In general, it seems that the addition at a relatively low temperature in the initial stage of the reaction is preferable from the viewpoint of relieving heat shock, but in the present invention, the generation of particles that tend to aggregate due to excessive pulverization is suppressed. There is also an advantage that there is no.

  The concentration of the silica particles in the polyester resin composition in the present invention is not particularly limited, but is 0.1 to 10% by weight, preferably 0.5 to 8% by weight when used as a master polymer. When used as a film, it is usually 0.02 to 2% by weight, preferably 0.05 to 1.0%. When processed into a film or sheet, it is mixed and diluted with a polyester resin substantially free of particles. It is a reasonable production method to use a so-called master polymer method. Of course, there is no problem in using it alone as a straight polymer. At this time, a polyester resin composition containing particles other than silica particles, for example, inorganic particles such as alumina and calcium carbonate, or organic particles typified by silicone particles and polystyrene particles, is mixed, and two or more kinds are mixed. It is also possible to process into a film or sheet containing particles.

  The polyester resin in the present invention is a polyester resin comprising a dicarboxylic acid component and a glycol component, preferably a polyester resin having an aromatic dicarboxylic acid as the main acid component and an aliphatic glycol as the main glycol component, Examples of the aliphatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and specific aliphatic glycols include ethylene glycol, propylene glycol, 1,4-butanediol, and 1.4-cyclohexanedimethanol. It is done. Among these, polyethylene terephthalate and polyethylene-2,6-naphthalate can be particularly preferred. The above-mentioned polyester resin may be a homopolyester or a copolyester. In the case of a copolyester, the acid component is succinic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid (the acid component is 2,6-naphthalenedicarboxylic acid), 2,6-naphthalenedicarboxylic acid (when the acid component is terephthalic acid), 5-sodium dicarboxylic acid or isomers of naphthalenedicarboxylic acid, and the glycol component is diethylene glycol, Examples include alkylene glycols such as propylene glycol and butanediol, and 1,4-cyclohexanedimethanol.

  Finally, the manufacturing method of the polyester film of this invention is demonstrated. The polyester film production method of the present invention uses the polyester resin composition obtained by the above-described production method of the present invention as at least a part of the raw material, and, in addition, a method known per se is suitably employed. it can. That is, even the polyester resin composition obtained by the production method of the present invention alone is mixed with other polyester resin compositions as described above, melt-kneaded, and from a die such as a T-die or I-die, a cooling drum The film may be extruded and rapidly cooled and solidified, and if necessary, a stretching process such as biaxial stretching or simultaneous biaxial stretching or a heat setting process may be performed according to the properties of the target film.

Hereinafter, the present invention will be described in more detail with reference to examples. In addition, each characteristic value in an Example was measured or evaluated with the following method.
(1) Average particle size and particle size distribution of silica particles Measurement was performed in a state where light anhydrous silicic acid particles were dispersed by dilution with ethylene glycol using a laser scattering particle size distribution measuring apparatus, SALD-2000, manufactured by Shimadzu Corporation. All measured values show calculation results using a refractive index of 1.45. The average particle diameter (d50) represents a volume-based 50% cumulative particle diameter, and the ratio of particles of 5 μm or more represents a value obtained by subtracting a value of 5 μm or less integrated from a small particle diameter from 100%, and 1.5 μm or less. The particle ratio represents a value of 1.5 μm or less accumulated from the small particle diameter.
(2) Intrinsic Viscosity of Polyester Resin Composition Polyethylene terephthalate was measured in an O-chlorophenol solvent, and polyethylene naphthalate was measured in a phenol / tetrachloroethane (50/50) solvent, both in an atmosphere of 35 ° C.
(3) Specific surface area The specific surface area / pore distribution measuring device manufactured by Yuasa Ionics, a gas adsorption method using nitrogen gas with NOVA1000, and a BET multipoint method specific surface area measurement method were used.
(4) Evaluation of coarse particles in polyester film Plasma treatment (plasma reactor PR-31 type manufactured by Yamato Scientific) is applied to the surface of the polyester resin composition, the particles are exposed on the surface, and after carbon deposition, an electron microscope is used. 200 particles were randomly photographed at a magnification of 10,000 times, and an equivalent circle diameter was obtained by an image analyzer, and particles of 5 μm or more were counted as coarse particles. In addition, the whole aggregated particle exceeding 5 μm was counted as one coarse particle.
The evaluation level was implemented as follows.
A: The number of coarse particles is 2 or less.
A: The number of coarse particles exceeds 2 and is 20 or less.
X: There are 21 or more coarse particles.

[Example 1]
(1) Preparation of slurry
50 g of light anhydrous silicic acid (Microid ML384 manufactured by Tokai Chemical Co., Ltd.) having a BET value of 310 m ² / g and an average particle size (d50) of 2.5 μm is added to 950 g of ethylene glycol, and mixed for 20 minutes with a home tabletop mixer to give 5 % Slurry was prepared. This operation was repeated 10 times and all were mixed to prepare a total amount of 10,000 g of slurry. This slurry was put into a high pressure state of 80 MPa using a continuous atomizer system optimizer system HJP-25005 manufactured by Sugino Machine, discharged from nozzles facing each other, and the entire amount was crushed by collision of particles. This crushing treatment was repeated twice, and then this treatment solution was filtered through a cartridge grade 070 (99.98% filtration accuracy equivalent to 7 μm) of Nihon Pall filter profile II to obtain a final slurry.
Table 1 shows the properties of the resulting glycol slurry.

(2) Production of polyester resin composition
A mixture of 100 parts of dimethyl terephthalate and 70 parts of ethylene glycol was charged with 0.038 parts of manganese acetate tetrahydrate in a transesterification reaction kettle and gradually heated from 140 ° C to 230 ° C. The transesterification reaction was carried out while distilling off. At 210 ° C. during methanol distillation, 10 parts of the previously prepared light anhydrous silicic acid slurry was added in an amount corresponding to 5% by weight. After the distillation of methanol was completed, 0.017 part of orthophosphoric acid was added as a phosphorus compound to terminate the reaction. Then, after 5 minutes, 0.030 part of polymerization catalyst antimony trioxide was added and heated to 240 ° C. to distill a part of ethylene glycol, and then the oligomer was transferred to a polycondensation reaction kettle. Thereafter, the reaction is terminated when the desired viscosity is reached at a final internal temperature of 290 ° C. while heating in a high vacuum according to a conventional method, and is continuously extruded from the discharge part into a strand shape, and cooled and cut to about 3 mm. Before and after granular pellets were obtained. The intrinsic viscosity of this polymer was 0.60. Table 1 shows the characteristics of the obtained polyester resin composition.

(3) Manufacture of a polyester film 10 parts of the polyester resin composition obtained in the above (2) and the inherent property obtained by repeating the same operation except that the light anhydrous silicic acid slurry was not added in the above (2) 90 parts of a polyester resin composition with a viscosity of 0.62 is mixed, dried in a vacuum dryer at 140 ° C. for 4 hours, melt-extruded at 290 ° C., and passed through a fiber sintered stainless steel filter having an opening of 30 μm. Then, the sheet was discharged from a T-die in a sheet form, and the sheet was brought into close contact with a cooling drum having a surface temperature of 30 ° C. to rapidly cool and solidify to obtain a non-oriented polyester film. Subsequently, this non-oriented film was stretched 3.5 times at 90 ° C., then stretched 3.5 times in the transverse direction at 130 ° C., and then relaxed by 3% in the longitudinal direction to a temperature zone of 220 ° C. Then, the film was led to a temperature zone of 180 ° C. while being relaxed by 2% in the transverse direction, and then cooled to room temperature, and the film edge was removed to obtain a polyester film having a thickness of 20 μm. The properties of the obtained film are shown in Table 1.

[Examples 2 to 5]
In the slurry preparation in Example 1, a glycol slurry was prepared by repeating the same operation as in Example 1 except that the pressure in the high pressure state and the number of passes of the crushing treatment were performed under the conditions shown in Table 1. Subsequently, the same operation as in the method for producing the polyester resin composition of Example 1 was repeated to produce a polyester resin composition, and the same operation as in Example 1 was repeated to produce a polyester film. Table 1 shows the properties of the obtained glycol slurry, polyester resin composition and polyester film.

[Example 6]
Using the same slurry as in Example 1, a polyester resin composition was produced as follows.
A mixture of 100 parts of dimethyl 2,6-naphthalene and 60 parts of ethylene glycol was charged with 0.030 part of manganese acetate tetrahydrate in a transesterification reactor, and gradually heated from 140 ° C to 230 ° C while being gradually heated. The transesterification reaction was carried out while distilling methanol out of the system. During this period, the light silicic acid slurry prepared in Example 1 (1) at 190 ° C. was added with 10 parts in an amount of 5% by weight, and the reaction was continued. After complete distillation of methanol, phosphoric acid was used as the phosphorus compound. 0.020 parts of trimethyl was added to terminate the reaction. Subsequently, 0.05 part of polymerization catalyst antimony trioxide was added after 5 minutes and heated to 250 ° C. to distill a part of ethylene glycol, and then the oligomer was transferred to a polycondensation reaction kettle. Thereafter, the reaction is terminated when a desired viscosity is reached at a final internal temperature of 295 ° C. while heating in a high vacuum in accordance with a conventional method. Before and after, pellets of polyethylene-2,6-naphthalate were obtained. The intrinsic viscosity of this polymer was 0.61.

  Next, a polyester (polyethylene with an intrinsic viscosity of 0.61) produced in the same manner except that 10 parts of the obtained polyester (polyethylene-2,6-naphthalate) resin composition and a slurry of light anhydrous silicic acid were not added. -2,6-naphthalate) 90 parts of a resin composition were mixed, dried with a hot air dryer at 180 ° C. for 5 hours, melt extruded at 300 ° C., and passed through a 30 μm fiber sintered stainless metal filter. Thereafter, the sheet is discharged in a sheet form from a T-die, and the sheet is brought into close contact with a cooling drum having a surface temperature of 40 ° C. to rapidly cool and solidify to obtain a non-oriented polyester film. Stretched twice, then stretched transversely at 140 ° C to 3.2 times, heat-set at 210 ° C to remove the film edges, and a 15μ thick polyester A film was obtained. Table 1 shows the physical properties of the obtained polyester resin composition and polyester film.

[Example 7]
In the slurry preparation in Example 6, a glycol slurry was prepared by repeating the same operation except that the pressure in the high pressure state and the number of passes of the crushing treatment were performed under the conditions shown in Table 1. Subsequently, a polyester resin composition was produced by repeating the same operation as in the method for producing a polyester resin composition of Example 6, and a polyester film was produced by repeating the same operation as in Example 1. Table 1 shows the properties of the obtained glycol slurry, polyester resin composition and polyester film.

[Comparative Example 1]
In the slurry preparation in Example 1, the crushing process by the continuous atomizer optimizer system was omitted, and the filtration process was an MCY type cartridge grade 150 (99.98% filtration accuracy equivalent to 15 μm) manufactured by Nihon Pall. The treatment was performed in the same manner as the slurry preparation method of Example 1 except that the filtration was changed to a filter. In the filtration process, the filter grade II of Nippon Pole's Filter Grade II (99.98% filtration accuracy equivalent to 7 μm) as well as the cartridge grade 100 (99.98% filtration accuracy equivalent to 10 μm) filter is immediately increased in pressure. Could not be filtered.

Subsequently, the same operation as in the production method of Example 1 was repeated to produce a polyester resin composition, and the same operation as in Example 1 was repeated to produce a polyester film.
Table 1 shows the properties of the obtained glycol slurry, polyester resin composition and polyester film.

[Comparative Example 2]
In the slurry preparation in Example 1, instead of crushing treatment by a continuous atomizer optimizer system, a horizontal sand mill device manufactured by Toshiba Barotini (current name Potters Barotini) was used, and a particle size of 0.6 to Filled with 0.85mm low-alkaline large beads at 80% filling rate, using a crushing process that passes twice at a peripheral speed of 12m / sec and an average passing time of 2 minutes. Cartridge grade 100 (99.98% filtration accuracy equivalent to 10 μm) The same operation was repeated except that filtration was performed using an MCY type filter. Next, the same operation as in Example 1 was repeated to produce a polyester resin composition, and the same operation as in Example 1 was repeated to produce a polyester film. In the filtration process, the filter profile II cartridge grade 070 (corresponding to 99.98% filtration accuracy of 7 μm) manufactured by Nippon Pole was immediately pressurized and could not be filtered.
Table 1 shows the properties of the obtained glycol slurry, polyester resin composition and polyester film.

  According to the present invention, the particle itself can be crushed while suppressing the generation of coarse particles in a short time to near the particle size distribution of the primary particles originally possessed, and the filterability is greatly improved, so that a finer filter. Thus, it is possible to obtain a glycol slurry containing silica particles in which aggregated particles and coarse particles are greatly reduced. And in the film and sheet-like product obtained by processing the polyester resin composition and the resin composition by using the glycol slurry crushed uniformly in this way, coarse particles such as aggregated particles can be suppressed, For example, a film or sheet capable of obtaining a high degree of transparency can be produced, and it can be suitably used for producing a film such as DFR (Dry Photo Film Resist) particularly requiring high transparency.

Claims (7)

A glycol slurry containing silica particles having a specific surface area of 150 to 450 m ² / g and an average particle size of 2.0 to 4.0 μm is brought into a high pressure state of 50 to 150 MPa, and then the glycol slurries collide with each other from the nozzles facing each other. The silica particles are crushed and then filtered through a filter having an absolute filtration accuracy of 10 μm or less , and
The manufacturing method of the polyester resin composition for films which consists of the process of adding this filtration slurry slurry to a polyester reaction system, and performing a polymerization reaction . The method for producing a polyester resin composition according to claim 1, wherein the polyester resin is polyethylene terephthalate or polyethylene-2,6-naphthalate . The method for producing a polyester resin composition for a film according to claim 1, wherein the silica particles are particles made of light anhydrous silicic acid . The method for producing a polyester resin composition for a film according to claim 1, wherein the crushing treatment is repeated twice or more at a high pressure of 50 to 150 MPa . 2. The method for producing a polyester resin composition for a film according to claim 1, wherein the ratio of particles having a particle diameter of 5 μm or more is 2% or less, based on the volume of all particles in the filtered glycol slurry . The method for producing a polyester resin composition for a film according to claim 1, wherein the ratio of the particles having a particle diameter of 1.5 µm or less is 20% or less in the glycol slurry subjected to filtration treatment, based on the volume of all particles . A method for producing a polyester film , wherein the polyester resin composition obtained by the method according to claim 1 is melt-extruded into a sheet and processed into a film .