JP6290721B2 - Polyester resin composition - Google Patents

Description

  The present invention relates to a polyester resin composition containing porous silica particles. More specifically, even if a portion of the laminated polyester film having a surface layer for improving the surface properties is reused, for example, in the core layer of the laminated film (hereinafter sometimes referred to as self-recovery). Further, the present invention relates to a polyester resin composition suitable for use as a surface layer of a laminated polyester film, in which the porous silica particles can be easily crushed during the recovery step, and thus good film forming properties can be obtained.

  The edge light type backlight unit has a structure in which the light guide plate and the reflective film are in direct contact with each other. If the light guide plate and the reflective film are attached, the luminance of the attached portion becomes abnormal, and the luminance varies in the surface. There is a problem that will occur. Therefore, it is considered that beads are provided on the surface of the reflective film to keep the gap between the light guide plate and the reflective film constant, thereby preventing these sticking. At this time, if the light guide plate made of a relatively soft material comes into contact with the reflective film, there is a problem that the light guide plate is damaged by the reflective film or the beads on the surface. Therefore, for example, as in Patent Documents 1 and 2, there is a report of a reflective sheet having a coating layer using elastomeric beads.

However, when soft beads as in Patent Documents 1 and 2 are used, damage to the light guide plate is suppressed, but the recently required gap cannot be achieved. For example, if a relatively large stress is applied, the gap is secured. In some cases, sticking cannot be suppressed.
In recent years, white polyester films are often used as the reflective layer. In this case, the method of providing an anti-adhesion layer suitable for securing the gap as described above by coating requires a separate coating process or does not become a product when forming a white polyester film. There was a problem that the recovered part could not be collected and reused.

JP 2003-92018 A Special table 2008-512719 gazette

  Therefore, the object of the present invention is to form a sticking prevention layer that can ensure a uniform gap by simply laminating the white polyester film or the like on the surface by coextrusion, An object of the present invention is to simply provide a polyester resin composition capable of recovering and reusing, in particular, self-collecting, a laminated film that has not been obtained.

  As a result of intensive studies to achieve the above-mentioned object, the present inventor has recovered a specific porous silica particle as a bead by melting and kneading it into a polyester resin, thereby ensuring an appropriate gap and collecting it when reused. It was found that the porous silica particles were easily crushed during the process and could be used as it is in, for example, the white polyester film which is the other side of the coextrusion, and the present invention was completed.

Thus, according to the present invention,
“1. Polyester resin has an average secondary particle diameter of 10 to 100 μm, a compression rate of 9.8 × 10 ⁻⁴ N ( 0.1 gf ) load is 30% or more, and 4.9 × 10 ⁻⁴ N ( 0.05 gf ) A polyester resin composition obtained by melt-kneading porous silica particles having a compression rate of 25% or less under load so that the content is 0.1 to 10% by mass,
The polyester resin of the resin composition contains a phosphorus compound in an amount of phosphorus element of 50 to 150 mmol% based on the number of moles of all acid components of the polyester resin, and the secondary particle size in the resin composition is 8 μm. The ratio of the following porous silica particles is 45% by mass or less based on the mass of the total porous silica particles, and the melt viscosity of the resin composition (melting point of polyester resin + temperature of 20 ° C., shear rate 1000 sec ⁻¹ ) Is a polyester resin composition characterized by being 200 to 450 Pa · s.
2. 2. The polyester resin composition according to 1 above, which is used for a surface layer of a laminated film laminated by coextrusion. "
Is provided.

  In the resin composition of the present invention, porous silica particles having a specific particle size and a specific compression rate are melt-kneaded in a polyester resin, and the ratio of the small particle size and the melt viscosity in the composition are specified. It is particularly suitable for the prevention layer of the anti-adhesion layer laminated film capable of ensuring a uniform gap and reusing the recovered film.

  The polyester resin composition of the present invention is obtained by melt-kneading specific porous silica particles described later in the following polyester resin.

  As the polyester resin in the present invention, it is preferable to use a polyester resin composed of a dicarboxylic acid component and a diol component. Examples of the dicarboxylic acid component include components derived from terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, adipic acid, sebacic acid and the like. Examples of the diol component include components derived from ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, and the like. Among the polyesters composed of such components, aromatic polyesters are preferable, polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate are particularly preferable, and polyethylene terephthalate is particularly preferable. Polyethylene terephthalate may be a homopolymer, but a copolymer is preferable from the viewpoint that crystallization is suppressed when the film is stretched uniaxially or biaxially and stretchability and film-forming property are improved. Examples of the copolymer component include the dicarboxylic acid component and the diol component described above, and isophthalic acid and 2,6-naphthalenedicarboxylic acid are preferable from the viewpoint of achieving both heat resistance and film forming properties. The proportion of the copolymerization component is, for example, 1 to 20 mol%, preferably 2 to 18 mol%, more preferably 3 to 15 mol%, particularly preferably 7 to 11 based on 100 mol% of the total dicarboxylic acid component of the polyester. Mol%. By making the ratio of a copolymerization component into this range, it is excellent in the improvement effect of film forming property. Moreover, it is excellent in thermal dimensional stability.

  By the way, the intrinsic viscosity of the polyester resin used for melt kneading is not particularly limited as long as the melt viscosity of the composition described later is satisfied, but the intrinsic viscosity is liable to decrease due to thermal deterioration due to melt kneading, and if it is too low, the machine It is preferable that the strength is 0.50 dl / g or more, more preferably 0.60 dl / g or more, and most preferably 0.70 dl / g or more.

(Porous silica particles)
The porous silica particles in the present invention are required to have an average secondary particle diameter of 10 to 100 μm. As a result, when the film is laminated on the surface layer, the distance from the light guide plate is kept constant, and it is possible to satisfactorily suppress the sticking of these, and the stretchability during film formation includes the case of using a self-recovery raw material. It becomes good. When the average secondary particle diameter is too small, the laminated film (white reflective film or the like) tends to be partially adhered to the light guide plate. From such a viewpoint, the average secondary particle diameter is preferably 12 μm or more, more preferably 14 μm or more, still more preferably 15 μm or more, and particularly preferably 16 μm or more. On the other hand, when it is too large, it tends to be inferior in stretchability and inferior in recoverability, that is, it tends to be inferior in film forming property of the film after self-collection. Further, the particles tend to drop off, and when the drop occurs, for example, a white spot defect occurs in a backlight unit. From such a viewpoint, the average secondary particle diameter is preferably 95 μm or less, more preferably 90 μm or less, still more preferably 85 μm or less, particularly preferably 80 μm or less, and most preferably 30 μm or less.

  The porous silica particles are preferably aggregated particles obtained by aggregating primary particles, and the primary particle diameter is preferably 0.01 μm or more, and preferably 5 μm or less. By satisfying this and the above-mentioned average secondary particle size range at the same time, it is possible to further enhance the effect of improving the film forming property when using the self-recovery raw material. If the primary particle size is too small, the strength of the aggregated particles tends to be too weak, and it is difficult to obtain a sufficiently large average secondary particle size. From this viewpoint, the primary particle diameter is more preferably 0.02 μm or more, further preferably 0.03 μm or more, and particularly preferably 0.05 μm or more. On the other hand, if it is too large, even if the secondary particles are destroyed during the production of the self-recovery raw material, particles having a relatively large particle size still remain, and the effect of improving the film-forming property after recovery is low. Tend to be. From this viewpoint, it is more preferably 4 μm or less, further preferably 3 μm or less, particularly preferably 2 μm or less, and most preferably 1 μm or less.

  Furthermore, the porous silica particles in the present invention have a crushing strength capable of maintaining a secondary particle diameter to the extent that a sufficient gap can be obtained at the polyester resin composition production stage and the film production stage, and a recovery stage. Therefore, it is necessary to have an optimum strength to be crushed, and the compression rate (0.05 gf compression rate) when a load of 0.05 gf is applied needs to be 25% or less. Preferably it is 20% or less, most preferably 15% or less. If this compression ratio exceeds the upper limit, the porous silica particles are crushed at the film forming stage, making it difficult to obtain a sufficient gap.

On the other hand, from the viewpoint of crushing the porous silica particles during recovery, the compression ratio (0.1 gf compression ratio) when a 0.1 gf load is applied needs to be 30% or more. If the compression rate of 0.1 gf is high, the particles are likely to be crushed during collection, preferably 40% or more, and more preferably 50% or more. When this compression ratio is less than the lower limit, the particles in the recovered film are not crushed and the film-forming property of the film is easily impaired when reused as a self-recovery raw material.
The compression ratio was measured by using a micro compression test MCTM-200 manufactured by Shimadzu Corporation, selecting a particle having a substantially average particle diameter, performing a compression test under the condition of a load loading speed of 0.0725 gf / sec, and measuring n = 5. The average value was calculated.

  The melt-kneading ratio of the porous silica particles to the polyester resin needs to be in a range of 0.1 to 10% by mass based on the mass of the obtained polyester resin composition. If the kneading ratio is too small, there are few surface irregularities when laminated on the surface layer of the white reflective film, and the distance from the light guide plate cannot be kept constant. Therefore, it is more preferably 1% by mass or more, particularly preferably 2% by mass or more. On the other hand, when too large, productivity at the time of film formation deteriorates, or the mechanical strength of the obtained film tends to be insufficient. Furthermore, the amount of particles during self-collection increases, which makes it difficult to increase the recovery rate. Therefore, it is more preferably 8% by mass or less, particularly preferably 7% by mass or less.

(Phosphorus compound)
In the present invention, when the porous silica particles are melt-kneaded with the above polyester resin, the amount of phosphorus element is 50 to 150 mmol in the polyester resin of the resulting composition based on the number of moles of all acid components of the polyester resin. It is necessary to make it contain in the range of%. As for the content of the phosphorus compound, if the amount of the phosphorus compound is large, the hue and the thermal stability are increased. However, if the amount is too large, the polymerization reaction time is significantly delayed by the addition during the polymerization reaction, or the purpose. There is a risk that problems such as not reaching the intrinsic viscosity of the resin may occur, and the addition during melt-kneading may increase the intrinsic viscosity. The preferred lower limit of the amount of phosphorus compound is 60 mmol%, further 70 mmol%, while the preferred upper limit is 120 mmol%, further 90 mmol%.

  The specific phosphorus compound is not particularly limited as long as it has a phosphorus element in the compound. For example, phosphoric acid, phosphorous acid, trimethyl phosphate (TMP), tributyl phosphate, triphenyl phosphate Ester, phosphoric acid monomethyl ester, phosphoric acid dimethyl ester, phenylphosphonic acid, phenylphosphonic acid dimethyl ester, phenylphosphonic acid diethyl ester, ammonium phosphate, triethylphosphonoacetate (TEPA), methyldiethylphosphonoacetate, etc. These phosphorus compounds may be used in combination of two or more. Among these, phosphoric acid trimethyl ester, triethylphosphonoacetate, and methyldiethylphosphonoacetate are preferable.

  In addition, the addition time of the phosphorus compound is not particularly limited, and may be at the time of production of the polyester resin or at the time of melt-kneading the polyester resin and the porous silica particles. It is preferable to carry out during the initial stage of the polycondensation reaction, which is the second reaction, after the transesterification reaction or esterification reaction is substantially completed, and the addition may be carried out all at once or divided into two or more times. You may go.

(Other ingredients)
The polyester resin composition of the present invention is different from other components such as ultraviolet absorbers, antioxidants, antistatic agents, fluorescent brighteners, waxes, and void forming agents as long as the object of the present invention is not impaired. Particles, resins and the like can be contained.

(Production method of polyester resin composition)
The polyester resin composition of the present invention is not particularly limited as long as the above-described polyester resin and porous silica particles are melt-kneaded. For example, the polyester resin composition is a first resin that is heated to a molten state. Preferably, it is produced by melt kneading comprising the following steps: a second step of adding porous silica particles to the molten polyester resin and a third step of kneading the molten polyester resin and porous silica particles, These steps are usually performed in the same kneading extruder.

  The kneading extruder used here may be a single-screw kneading extruder or a twin-screw kneading extruder, but a twin-screw kneading extruder is preferred because it can easily form a uniform kneading state. The twin-screw kneading extruder is not particularly limited. For example, a vent-type twin-screw kneading extruder having a screw configuration in which kneading disks and reverse screw kneading elements are arranged, or a rotor-type twin-screw kneading extruder may be used. preferable. In order to prevent the silica particles to be added from being crushed, it is preferable to use a biaxial kneading extruder that rotates in the same direction. As a specific rotor type twin-screw kneader, the rotor consists of a screw part that feeds the material supplied from the hopper to the chamber and a kneading blade part that crushes, melts and kneads the material, and the degree of filling of the material A first stage two-shaft kneading type consisting of a throttle mechanism that adjusts the discharge to the outside of the chamber, and a second stage screw section where the rotor feeds the melted material after the first stage kneading blade section, Furthermore, it has a second stage kneading wing part to be kneaded, a throttle gate mechanism between the first stage and the second stage, and finally a two-stage biaxial kneading composed of a discharge orifice There are extrusion types. Also, the kneading extruder is preferably a vent type kneading extruder because it can discharge by-product gas generated in the kneading extruder, and in particular, a vent type capable of low vacuum suction and high vacuum suction because decomposition of the polyester resin can be suppressed. A kneading extruder is preferred.

  In the biaxial kneading extruder as described above, the polyester resin is put into the extruder as a chip and softened by heating. Next, the porous silica particles are introduced, and an inlet for the porous silica particles is provided on the downstream side from the position where 80% by weight or more, more preferably 90% by weight or more, of the previously charged polymer is softened. It is done. If an inlet for the porous silica particles is installed upstream of this, the porous silica particles are not sufficiently dispersed by mixing with the unmelted polyester resin, and are aggregated in the extruder, or the resulting composition is produced. It becomes a factor for generating voids when the film is stretched.

  Moreover, the porous silica particles to be introduced may be subjected to surface treatment with a phosphorus stabilizer or a silane coupling agent in advance. The phosphorus stabilizer may be the same as or different from the phosphorus compound contained in the polyester resin. Moreover, although it does not specifically limit about a silane coupling agent, For example, conventionally well-known silane coupling agents, such as a vinyl triethoxysilane, are used. By using these surface treatment agents, the surface activity of the porous silica particles with respect to the polyester resin during melt kneading can be deactivated, and the thickening effect due to the silica particles, the inherent viscosity deterioration of the polyester resin, and the like can be suppressed.

  Furthermore, when adding the porous silica particles, it is preferable to add them in a state of being uniformly mixed with 50% by mass or more of the polyester resin powder based on the total mass of the porous silica particles. By adding at the same time as the polyester resin powder, the polyester resin powder that is relatively easy to melt prevents aggregation of the porous silica particles and facilitates uniform dispersion. Furthermore, by introducing polyester resin powder of a certain size at the same time, relatively bulky porous silica particles can be easily introduced into the cylinder. At this time, the particle diameter of the polyester resin powder shall pass a sieve opening of 16 mesh (1.0 mm) of JIS standard. If a powder having a particle size that does not pass through the mesh is used, it is difficult to melt, so that the porous silica particles are melted and kneaded in a biased state, which causes aggregation. The composition of the polyester resin (powder) is preferably the same as the polyester resin chip used for melt-kneading, but a composition having a different composition may be used as long as it does not exceed the requirements of the present invention. The powder having such a particle size can be obtained, for example, by freeze pulverization in which a polyester resin is heated to crystallize and then pulverized in a state cooled with liquid nitrogen or the like.

Thus, the melt viscosity of the polyester resin composition of the present invention obtained by melt-kneading (melting point of polyester resin + temperature at 20 ° C., viscosity at a shear rate of 1000 sec ⁻¹ ) needs to be 200 to 450 Pa · s. , Preferably 250 to 400 Pa · s. When the melt viscosity is less than 200 Pa · s, not only the crushing of the porous silica particles during self-recovery is difficult to proceed, but also the intrinsic viscosity of the polyester resin is low and the mechanical strength of the film tends to be insufficient. . On the other hand, when it exceeds 450 Pa · s, the shear stress at the time of melt-kneading becomes too high, so that the pulverization of the porous silica particles tends to proceed at the time of melt-kneading, and the secondary particle diameter in the composition is 8 μm or less. This is a problem because not only the ratio of the porous silica particles is increased, but also the process stability when forming a film or the like is lowered. In addition, what is necessary is just to adjust the intrinsic viscosity of a polyester resin according to the particle size of the porous silica particle to be used, the kneading amount, and the presence or absence of surface treatment in order to make melt viscosity into the said range.

  Further, the ratio of the porous silica particles having a secondary particle diameter of 8 μm or less in the polyester resin composition of the present invention needs to be 45% by mass or less based on the mass of the total porous silica particles, preferably 40 It is below mass%. When this proportion exceeds 45% by mass, the film surface unevenness due to the porous silica particles is reduced even as a laminated film in which this composition is arranged on the surface layer, and the action as an anti-bonding layer becomes insufficient. It is difficult to secure a sufficient band gap.

  Furthermore, the intrinsic viscosity of the polyester resin composition of the present invention is preferably 0.48 dl / g or more, particularly preferably 0.50 dl / g or more. If the intrinsic viscosity is too low, it tends to cause breakage or lamination unevenness in film-forming stretching to a laminated film or the like. On the other hand, if the upper limit of the intrinsic viscosity is too high, it tends to be difficult to satisfy the ratio of the porous silica particles having a secondary particle diameter of 8 μm or less in the polyester resin composition, and the film forming property tends to be lowered. Therefore, it is preferably 0.65 dl / g or less, more preferably 0.60 dl / g or less.

  The polyester resin composition of the present invention described above can be formed into a stretched film by extruding it into a sheet by a method known per se and further stretching in the film forming direction, the width direction, or both directions. Although the polyester resin composition of the present invention may be used alone as a stretched film, as described at the beginning, when a white polyester film or the like is melt-formed, it is only laminated on the surface of the white polyester film by coextrusion. Since a uniform gap can be secured, and a portion that has not become a product can be recovered and reused, it is particularly preferably used for the surface layer of a coextruded laminated film. In addition, the coextrusion method itself can employ a method known per se.

  When the polyester film using the polyester resin composition of the present invention is recovered and reused, a kneading extruder is used as a means for pulverizing the porous silica particles. It is preferable to use a direction rotating kneading extruder. Further, as a screw configuration, in order to enhance the crushability, it is preferable to dispose two or more kneading elements for the kneading disk and the reverse screw, preferably three or more.

  Hereinafter, the present invention will be further described by examples. In addition, the physical property and characteristic in an Example were measured or evaluated by the following method.

(1) Intrinsic viscosity The intrinsic viscosity of the polyester resin is that the polymer is dissolved by using a mixed solvent of P-chlorophenol / 1,1,2,2-tetrachloroethane (40/60 weight ratio), and the polymer is centrifuged. The minutes were separated and determined by measuring at 35 ° C.

(2) Content of porous silica particles 10 g of a sample is put in a crucible, heated at 500 ° C. for 6 hours using an electric furnace, the weight of only the residue is measured, and the content of porous silica particles as ash Asked.

(3) Load compression rate Using a micro compression test MCTM-200 manufactured by Shimadzu Corporation, a particle having a substantially average particle diameter is selected, a compression test is performed under the condition of a load load rate of 0.0725 gf / sec, and n = 5 is measured. The average value was calculated.

(4) Average secondary particle diameter of porous silica particles Using an S-4700 field emission scanning electron microscope manufactured by Hitachi, Ltd., observation was performed at a magnification of 1000 times, the particle diameter was arbitrarily measured, and the average value was measured. From the average secondary particle diameter (ds). In the case of other than the spherical shape, (major axis + minor axis) / 2 was determined as the particle diameter. Here, the minor axis indicates the maximum diameter in the direction perpendicular to the major axis.

(5) Secondary particle diameter of porous silica particles in polyester resin composition The polyester resin composition was dissolved by heating with triethylene glycol, diluted with ethylene glycol, and measured with SALD-7000 manufactured by Shimadzu Corporation.

(6) Amount of phosphorus element in polyester resin The amount of phosphorus element in the polyester resin and the chip were heated and melted to prepare a circular disk, which was measured using a Rigaku fluorescent X-ray measurement apparatus 3270. In addition, when additive particles such as porous silica particles contain phosphorus element or are surface-treated with a phosphorus compound, the same measurement is performed after removing the lubricant by centrifugation in a solvent in advance. It was.

(7) Melt viscosity Using CFT-500D manufactured by Shimadzu Corporation, the melt viscosity was measured by heating to a temperature of the melting point of the polyester resin + 20 ° C., and the melt viscosity at a shear rate of 1000 sec ⁻¹ was determined.

(8) Thermal degradation characteristics The polyester resin composition was put into a beaker and kept at 290 ° C. for 1 hour under nitrogen filling, then the molten resin composition was plated, and the hue b value was measured with a color machine for 1 hour. Per hue change rate was classified as follows. The color machine was measured using a Nippon Denshoku color meter (ZE2000).
◎: 0 or more and less than 5 ○: 5 or more and less than 10 ×: 10 or more

(9) Film forming stretchability The polyester resin composition was melted in an extruder heated to its melting point (Tm: ° C) + 20 ° C, and then formed into a sheet from a die. Further, the unstretched film obtained by cooling and solidifying the sheet with a cooling drum having a surface temperature of 25 ° C. is preheated to 75 ° C., and is heated by a single infrared heater having a surface temperature of 800 ° C. from 15 mm above between the low speed roller and the high speed roller. However, the film was stretched in the longitudinal direction (longitudinal direction) and stretched in the direction perpendicular to the longitudinal direction (lateral direction) in an atmosphere heated to 120 ° C. Thereafter, heat setting was performed at a temperature of 200 ° C. in a tenter, and the film-forming stability when a biaxially stretched polyester film was obtained was observed and evaluated according to the following criteria.
A: The film can be stably formed for 3 hours or more.
○: A film can be stably formed for 1 hour or more.
Δ: Cutting occurred once in 1 hour.
X: Cutting occurs multiple times within 1 hour, and stable film formation is not possible.

(10) Evaluation of Crushing Rate A kneading disc having a film obtained by forming a polyester resin composition (Composition 1) in the film-forming stretch test of (9) above was heated to its melting point (Tm) + 30 ° C. It was supplied to a biaxial kneading extruder with a vent of different direction rotation meshing type, melt-kneaded and extruded at a rotation speed of 450 rpm, cooled with a water-cooled bath, and then chipped with a pelletizer to obtain a recovered polymer.
And the said composition 1 and the said collection | recovery polymer are each melt | dissolved at 290 degreeC, it blows out from the front-end | tip of a glass rod, a balloon film is created, magnification is used using S-4700 type field emission scanning electron microscope made from Hitachi, Ltd. The particle size of 100 particles was arbitrarily measured at 500 times, and the number of particles of 10 μm or more was measured. The reduction rate of 10 μm particles in the recovered polymer relative to the original composition 1 was calculated as the crushing rate.

[Example 1]
89 parts by mass of dimethyl terephthalate, 11 parts by mass of dimethyl isophthalate and 65 parts by mass of ethylene glycol were charged into a reaction vessel equipped with a rectifying column and a distillation condenser, and stirred and dissolved at 150 ° C. or lower. Thereafter, 0.04 parts by mass of manganese acetate and 0.04 parts by mass of antimony trioxide were added, and the ester exchange reaction was carried out while raising the temperature from 140 ° C. to 240 ° C. with stirring. Then, trimethyl phosphate was used as the amount of phosphorus element. 0.008 part by mass (50 mmol% based on the total acid components) was added and stirred for 5 minutes. Thereafter, excess ethylene glycol was allowed to flow out of the reaction system and transferred to the polymerization reaction tank. After the transfer, the polycondensation reaction is performed while gradually raising the temperature in the reaction vessel from 240 ° C. to 290 ° C. under high vacuum, and after the completion of the reaction, it is extruded from the reaction layer. Copolymer polyethylene terephthalate resin (melting point: 225 ° C.) pellets having an amount of 50 mmol%, an isophthalic acid copolymerization amount of 11 mol% (based on all acid components), and an average pellet size of 2 × 2 × 4 mm were obtained. The obtained pellets were fed from a vibratory quantitative feeder at a rate of 20 kg / h to a twin-screw kneading extruder with a vent of the same direction rotating mesh type having a kneading disc paddle as a screw component.

  Next, 50 parts by mass of powder passing through a JIS standard sieve 16 mesh obtained by pulverizing the above-mentioned copolymerized polyethylene terephthalate resin, the average secondary particle diameter is 15 μm, and the compression rate at 0.05 gf load is 21%, 50 parts by mass of porous silica particles A (AY-603 manufactured by Tosoh Silica Co., Ltd.) having a compressibility of 40% at a load of 0.1 gf were mixed to prepare a uniform mixture. And it added using the screw type | mold quantitative feeder from the powder inlet of the above-mentioned extruder so that the porous silica particle might contain 8.0 mass% with respect to the resin composition which can obtain this mixture. At this time, the degree of vacuum at the vent port was 100 Pa, the cylinder temperature was 230 ° C., and the copolymerized polyethylene terephthalate resin at the time of addition was all softened (no polymer retaining the chip shape). After adding the particles, the copolymerized polyethylene terephthalate resin, the porous silica particles, and the copolymerized polyethylene terephthalate resin powder were kneaded, extruded from a polymer outlet in a molten state, and then pelletized to obtain a polyester resin composition. The properties of the obtained polyester resin composition are shown in Table 1.

[Example 2]
The melt kneading was carried out in the same manner as in Example 1 except that a copolymerized polyethylene terephthalate resin in which the amount of trimethyl phosphate added was changed to 0.013 parts by mass (80 mmol% based on the total acid components) as the amount of phosphorus element was used. And a polyester resin composition was obtained. The properties of the obtained polyester resin composition are shown in Table 1.

[Example 3]
Melt-kneading was carried out in the same manner as in Example 1 except that a copolymerized polyethylene terephthalate resin in which the amount of trimethyl phosphate added was changed to 0.018 parts by mass (110 mmol% based on the total acid components) as the amount of phosphorus element was used. And a polyester resin composition was obtained. The properties of the obtained polyester resin composition are shown in Table 1.

[Example 4]
Melt-kneading was carried out in the same manner as in Example 1 except that a copolymerized polyethylene terephthalate resin was used in which the amount of trimethyl phosphate was changed to 0.025 parts by mass (150 mmol% based on the total acid components). To obtain a polyester resin composition. The properties of the obtained polyester resin composition are shown in Table 1.

[Example 5]
A polyester resin composition was obtained by melt-kneading in the same manner as in Example 1 except that the content of the porous silica particles A was changed to 3.0% by mass. The properties of the obtained polyester resin composition are shown in Table 1.

[Example 6]
A polyester resin composition was obtained by melt-kneading in the same manner as in Example 2 except that the content of the porous silica particles A was changed to 10.0% by mass. The properties of the obtained polyester resin composition are shown in Table 1.

[Example 7]
A polyester resin composition was obtained by melt-kneading in the same manner as in Example 3 except that the content of the porous silica particles A was changed to 10.0% by mass. The properties of the obtained polyester resin composition are shown in Table 1.

[Example 8]
A polyester resin composition was obtained by melt-kneading in the same manner as in Example 4 except that the content of the porous silica particles A was changed to 10.0% by mass. The properties of the obtained polyester resin composition are shown in Table 1.

[Example 9]
A polyester resin composition was obtained by melt-kneading in the same manner as in Example 2 except that the phosphorus compound was changed to triethylphosphonoacetate. The properties of the obtained polyester resin composition are shown in Table 1.

[Example 10]
Except for changing the porous silica particles A to porous silica particles B (Carriert P-10 manufactured by Fuji Silysia Chemical Ltd.), melt-kneading was performed in the same manner as in Example 2 to obtain a polyester resin composition. The properties of the obtained polyester resin composition are shown in Table 1.

[Example 11]
Melting was performed in the same manner as in Example 2 except that the porous silica particles A were changed to porous silica particles C (powder obtained by removing 30 μm or more of carrier ct P-10 manufactured by Fuji Silysia Chemical Ltd. with an air classifier). Kneading was performed to obtain a polyester resin composition. The properties of the obtained polyester resin composition are shown in Table 1.

[Comparative Example 1]
Melt-kneading was carried out in the same manner as in Example 5 except that a copolymerized polyethylene terephthalate resin in which the addition amount of trimethyl phosphate was changed to 0.006 parts by mass (34 mmol% based on the total acid components) as the amount of phosphorus element was used. A lined polyester resin composition was obtained. The properties of the obtained polyester resin composition are shown in Table 1.

[Comparative Example 2]
A polyester resin composition was obtained by melt-kneading in the same manner as in Example 2 except that the content of the porous silica particles A was changed to 12.5% by mass. The properties of the obtained polyester resin composition are shown in Table 1.

[Comparative Example 3]
Except for changing the porous silica particles A to porous silica particles D (BY-001 manufactured by Tosoh Silica Co., Ltd.), melt-kneading was performed in the same manner as in Example 2 to obtain a polyester resin composition. The properties of the obtained polyester resin composition are shown in Table 1.

[Comparative Example 4]
A polyester resin composition was obtained by performing melt kneading in the same manner as in Example 2 except that the porous silica particles A were changed to porous silica particles E (P-78D manufactured by Mizusawa Chemical Co., Ltd.). The properties of the obtained polyester resin composition are shown in Table 1.

[Comparative Example 5]
Except for changing the porous silica particles A to porous silica particles F (BY-601 manufactured by Tosoh Silica Co., Ltd.), melt kneading was performed in the same manner as in Example 2 to obtain a polyester resin composition. The properties of the obtained polyester resin composition are shown in Table 1.

[Comparative Example 6]
A polyester resin composition was obtained by performing melt kneading in the same manner as in Example 2 except that the porous silica particles A were changed to porous silica particles G (ER-100 manufactured by Tosoh Silica Co., Ltd.). The properties of the obtained polyester resin composition are shown in Table 1.

  The polyester resin composition of the present invention can be easily produced, and a uniform gap can be secured only by laminating on the surface by coextrusion, and the recovered film can be reused, particularly self-collected. It can be suitably used as an anti-sticking layer provided on the surface of the film for a reflector of the apparatus.

Claims (2)

Polyester resin has an average secondary particle size of 10 to 100 μm, a compression rate of 30% or more when loaded with 9.8 × 10 ⁻⁴ N load, and a compression rate of 25 when loaded with 4.9 × 10 ⁻⁴ N load. % Is a polyester resin composition obtained by melt-kneading porous silica particles having a content of 0.1 to 10% by mass,
The polyester resin of the resin composition contains a phosphorus compound in an amount of phosphorus element of 50 to 150 mmol% based on the number of moles of all acid components of the polyester resin, and the secondary particle size in the resin composition is 8 μm. The ratio of the following porous silica particles is 45% by mass or less based on the mass of the total porous silica particles, and the melt viscosity of the resin composition (melting point of polyester resin + temperature of 20 ° C., shear rate 1000 sec ⁻¹ ) Is a polyester resin composition characterized by being 200 to 450 Pa · s.   The polyester resin composition according to claim 1, which is used for a surface layer of a laminated film laminated by coextrusion.