KR20190079991A - Polyester resin and polyester film using the same - Google Patents

Abstract

The present invention relates to a polyester resin and a polyester film using the same, specifically, relates to the polyester film used as a base film of a release film. More specifically, the present invention relates to the polyester film used in the release film of a multi-layer ceramic condenser (MLCC) and the polyester resin used for manufacturing the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a polyester resin,

The present invention relates to a polyester resin and a polyester film using the polyester resin, and relates to a polyester film used as a base film of a release film. More specifically, the present invention relates to a polyester film used in a release film of a multi-layer ceramic condenser (MLCC) and a polyester resin used for the production thereof.

Recently, demand for electronic materials has been increasing due to the high performance of IT devices such as smart phones, tablet PCs, 3D TVs, and smart TVs. Demand for release films used in electronic materials manufacturing processes is also steadily increasing. In such a situation, quality improvement is demanded as the customer's level of interest in the polyester film, which is the base film used in the release film, increases. Among these, there have been cases in which demands for improvements in handling properties such as roll driving property and windability during the film-forming process and the customer's post-processing process have arisen.

Film film forming and post-processing steps are speeded up and widened, defects such as scratches caused by slip and blocking caused thereby, defective product sections, and static electricity are deteriorated. Therefore, various methods such as film surface design and special surface treatment have been studied to improve the handling properties in the film forming and post-processing processes.

Specifically, in recent years, along with miniaturization and high performance of electronic devices, multilayer ceramic capacitors and multilayer ceramic substrates have been miniaturized and multilayered, and thinner ceramic green sheets have been developed.

A polyester film used as a base film of a release film in the manufacture of a multi-layer ceramic condenser (MLCC) includes a silicon release layer on one side or both sides. A ceramic green sheet is formed by coating a ceramic slurry containing a ceramic material such as barium titanate or titanium oxide on the release layer. When the thickness of the ceramic green sheet becomes thinner and the thickness after drying becomes, for example, 3 mu m or less, when ceramic slurry is coated and dried, defects such as pinholes and thickness irregularity due to the surface state of the release film, Can occur. For this reason, the polyester film used as the base film of the release film is required to have a high level of smoothness in contact with the ceramic slurry / ceramic green sheet. However, when the surface roughness is lowered on the surface contacting with the ceramic slurry / ceramic green sheet in order to achieve such high smoothness, the roll running property, windability and the like are lowered, scratches are generated, and the practical productivity is only about 25%.

As development has been focused on low-lightness and high planarization of the polyester base film for electronic materials as described above, there has been a problem that the yield of the winding is lowered because the effective protrusions, which are important for film-forming, are not produced.

Accordingly, there is a demand for a polyester resin composition and a polyester film produced using the polyester resin composition so that the surface of the polyester resin composition is highly flat and can exhibit effective protrusions for post-processing handling for smooth use by customers.

The present invention relates to a process for producing a film having a smooth surface but including an effective projection for improving post-processing handling and winding-up property of the film, and lowering the visibility of the film to increase the opacity so as not to expose non-intrinsic defects such as appearance, And a polyester resin used for producing the polyester film.

An object of the present invention is to provide a polyester film used as a base film for a release film having a low surface roughness and excellent handling properties and having opacity.

In addition, the present invention minimizes aggregation of inorganic particles, thereby preventing occurrence of defects such as pinholes and thickness irregularities in the functional layer to be applied in a post-process handling while having an effective projection, increasing the peak count of the surface, And a polyester film in which the defectiveness is remarkably reduced due to improvement in handling properties such as roll running property and windability during post-processing in a customer.

The surface flatness of the film is related to the surface roughness of the film. In order to control the surface roughness, the size of the particles included in the polyester resin must be small and constant, and the aggregation must be minimized. The agglomeration of the particles hinders the uniformity of the surface roughness and acts as an obstacle to the physical properties of the film. Increasing the opacity of the film also has the effect of lowering the visibility of the exterior so as not to reveal non-essential defects such as appearance that may occur during post-processing. The present invention aims to develop a resin composition for a polyester base film having surface roughness and opacity increasing effect by controlling the characteristics of particles.

One aspect of the present invention for achieving the above object is an image forming apparatus comprising inorganic particles A and inorganic particles B satisfying the following formulas 1 to 3 and having an average particle size of 0.1 To 1.0 占 퐉, a true specific gravity of 2.1 or less, and a pH of 6 to 9.

[Formula 1]

1.0? Bs / As? 10.0

(In the above formula 1, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B)

[Formula 2]

0.1? Bs? As? 0.9

(In the formula 2, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B.)

[Formula 3]

0.12? Bw / Aw? 1.5

(Where Aw is the content of the inorganic particles A and Bw is the content of the inorganic particles B).

Another aspect of the present invention is a coating composition comprising inorganic particles A and inorganic particles B satisfying the following formulas 1 to 3 and having an average particle size of 0.1 to 1.0 占 퐉 in a state of mixing the inorganic particles A and inorganic particles B, Of not more than 2.1 and an inorganic particle mixture having a pH of 6 to 9 in an amount of 0.05 to 1%

A polyester film having an average surface roughness of 10 nm or less, a maximum peak height of 100 nm or less, a peak count Pc of 1 to 10 pcs / mm 2, a haze of 7 to 10%, and a winding yield of 65% or more.

[Formula 1]

1.0? Bs / As? 10.0

(In the above formula 1, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B)

[Formula 2]

0.1? Bs? As? 0.9

(In the formula 2, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B.)

[Formula 3]

0.12? Bw / Aw? 1.5

(Where Aw is the content of the inorganic particles A and Bw is the content of the inorganic particles B).

Another aspect of the present invention relates to a method for producing a polyester resin,

Wherein the inorganic particles A and the inorganic particles B satisfy the following formulas 1 to 3 and have an average particle diameter of 0.1 to 1.0 占 퐉, a true specific gravity of 2.1 or less and a pH Is 6 to 9 is dispersed in ethylene glycol is added to the polyester slurry after the completion of the esterification reaction or the transesterification reaction until the start of the polycondensation reaction.

[Formula 1]

1.0? Bs / As? 10.0

(In the above formula 1, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B)

[Formula 2]

0.1? Bs? As? 0.9

(In the formula 2, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B.)

[Formula 3]

0.12? Bw / Aw? 1.5

(Where Aw is the content of the inorganic particles A and Bw is the content of the inorganic particles B).

The polyester film according to the present invention has good surface condition when applied to a release film, so that pinholes and defects do not occur even if a thin film layer is formed, and handling property such as roll driving property and windability is improved, There is an effect that can be greatly improved.

In addition, the polyester film according to the present invention can increase the opacity of the film, thereby lowering the visibility of the film, so that non-essential defects such as appearances in the post-processing can be obscured.

The polyester film of the present invention can be suitably used as a release film in the production of a multi-layer ceramic condenser (MLCC).

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described more fully hereinafter with reference to the accompanying drawings, It should be understood, however, that the invention is not limited thereto and that various changes and modifications may be made without departing from the spirit and scope of the invention.

Unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention is merely intended to effectively describe a specific embodiment and is not intended to limit the invention.

Also, the singular forms as used in the specification and the appended claims are intended to include the plural forms as well, unless the context clearly indicates otherwise.

One aspect of the present invention is a method for producing an inorganic particle comprising an inorganic particle A and an inorganic particle B satisfying the following formulas 1 to 3 and having an average particle diameter of 0.1 to 1.0 mu m in a state where the inorganic particle A and the inorganic particle B are mixed, Of 2.1 or less and an inorganic particle mixture having a pH of 6-9.

[Formula 1]

1.0? Bs / As? 10.0

(In the above formula 1, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B)

[Formula 2]

0.1? Bs? As? 0.9

(In the formula 2, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B.)

[Formula 3]

0.12? Bw / Aw? 1.5

(Where Aw is the content of the inorganic particles A and Bw is the content of the inorganic particles B).

In one embodiment of the present invention, the inorganic particle mixture may have a content of aggregated particles exceeding 1.0 mu m of 0.02% or less.

In one embodiment of the present invention, the inorganic particles A and the inorganic particles B may each independently be selected from titanium dioxide, barium sulfate, calcium carbonate, magnesium carbonate, calcium phosphate, silica, alumina, talc and kaolin.

In one embodiment of the present invention, the inorganic particle mixture may be contained in an amount of 0.1 to 5% by weight.

In one embodiment of the present invention, the inorganic particles A may be silica having an average particle diameter of 0.1 to 0.39 탆, and the inorganic particles B may be silica having an average particle diameter of 0.40 to 1.0 탆.

Another aspect of the present invention is a coating composition comprising inorganic particles A and inorganic particles B satisfying the following formulas 1 to 3 and having an average particle size of 0.1 to 1.0 占 퐉 in a state of mixing the inorganic particles A and inorganic particles B, Of not more than 2.1 and an inorganic particle mixture having a pH of 6 to 9 in an amount of 0.05 to 1%

A polyester film having an average surface roughness of 10 nm or less, a maximum peak height of 100 nm or less, a peak count of 1 to 10 pcs / mm 2, a haze of 7 to 10%, and a winding yield of 65% or more.

[Formula 1]

1.0? Bs / As? 10.0

(In the above formula 1, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B)

[Formula 2]

0.1? Bs? As? 0.9

(In the formula 2, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B.)

[Formula 3]

0.12? Bw / Aw? 1.5

(Where Aw is the content of the inorganic particles A and Bw is the content of the inorganic particles B).

In one embodiment of the present invention, the inorganic particles A and the inorganic particles B may each independently be selected from titanium dioxide, barium sulfate, calcium carbonate, magnesium carbonate, calcium phosphate, silica, alumina, talc and kaolin.

In one embodiment of the present invention, the inorganic particles A may be silica having an average particle diameter of 0.1 to 0.39 탆, and the inorganic particles B may be silica having an average particle diameter of 0.40 to 1.0 탆.

In one embodiment of the present invention, the polyester film may be a biaxially stretched film having a thickness of 20 to 40 탆.

Another aspect of the present invention relates to a method for producing a polyester resin,

Wherein the inorganic particles A and the inorganic particles B satisfy the following formulas 1 to 3 and have an average particle diameter of 0.1 to 1.0 占 퐉, a true specific gravity of 2.1 or less and a pH Is 6 to 9 is dispersed in ethylene glycol is added to the polyester slurry after the completion of the esterification reaction or the transesterification reaction until the start of the polycondensation reaction.

[Formula 1]

1.0? Bs / As? 10.0

(In the above formula 1, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B)

[Formula 2]

0.1? Bs? As? 0.9

(In the formula 2, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B.)

[Formula 3]

0.12? Bw / Aw? 1.5

(Where Aw is the content of the inorganic particles A and Bw is the content of the inorganic particles B).

In one embodiment of the present invention, the content of the agglomerated particles exceeding 1.0 mu m in the particle slurry may be 0.02% or less.

In one embodiment of the present invention, the inorganic particles A and the inorganic particles B may each independently be selected from titanium dioxide, barium sulfate, calcium carbonate, magnesium carbonate, calcium phosphate, silica, alumina, talc and kaolin.

In an embodiment of the present invention, when the particle slurry is added, the content of the inorganic particle mixture in the polyester resin may be 0.1 to 5% by weight.

In one embodiment of the present invention, the inorganic particles A may be silica having an average particle diameter of 0.1 to 0.39 탆, and the inorganic particles B may be silica having an average particle diameter of 0.4 to 1.0 탆.

Hereinafter, each configuration of the present invention will be described in more detail.

In one aspect of the present invention, the polyester resin may be one used as a master batch chip for producing a polyester film.

The inventors of the present invention have found that the use of a mixture of two kinds of inorganic particles having different particle diameters, the size and content of these particles are within a specific range, and the average particle diameter, true specific gravity and pH of the inorganic particle mixture are combined , It includes effective projections for suppressing the formation of coarse projections by secondary agglomeration to improve the film handling surface and windability of the film while the surface of the film is flat and lower the visibility of the outer appearance so that the non-intrinsic It is possible to increase the opacity so as not to reveal defects, thereby completing the present invention.

In one embodiment of the present invention, the polyester resin is not particularly limited, and may be one using a conventional polyester resin. Specifically, it can be obtained, for example, by condensation polymerization of an acid component containing a dicarboxylic acid as a main component and a glycol component containing an alkylene glycol as a main component. The dicarboxylic acid is not limited, but terephthalic acid or an alkyl ester or phenyl ester thereof may be used, and a part thereof may be a bifunctional carboxylic acid such as isophthalic acid, oxyethoxybenzoic acid, adipic acid, sebacic acid and 5-sodium sulfoisophthalic acid. It can be used by substituting the carboxylic acid or an ester-forming derivative thereof. The glycol component is not limited, but ethylene glycol is mainly used, and propylene glycol, neopentyl glycol, trimethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4- Ethoxybenzene, bisphenol, polyoxyethylene glycol and the like may be used in combination, and a monofunctional compound or a trifunctional compound may be used in combination.

In addition, it may contain one or more components selected from additives conventionally used in polyester resin polymerization, that is, a pinning agent, an antistatic agent, a UV stabilizer, a waterproofing agent, a slip agent and a heat stabilizer. It is not.

The polyester resin may be produced by TPA (Terephthalic acid) polymerization or DMT (dimethyl terephthalate) polymerization, which is a conventional polymerization method in the art, but is not limited thereto.

In one embodiment of the present invention, the polyester resin may be polyethylene terephthalate. That is, the polyester resin may be polyethylene terephthalate prepared by using terephthalic acid as a dicarboxylic acid and ethylene glycol as a glycol.

When the polyester film of the present invention is used as a base film of a release film by lowering the surface roughness, it is desired to prevent occurrence of pinholes and thickness unevenness in the layer applied to the release layer due to transfer of surface roughness, It is preferable to include two specific kinds of inorganic particles in order to improve the handling property such as winding property and the productivity to be greatly improved.

More specifically, it comprises inorganic particles A and inorganic particles B satisfying the following formulas 1 to 3 and having an average particle diameter of 0.1 to 1.0 占 퐉 and a true specific gravity of 2.1 Or less, and an inorganic particle mixture having a pH of 6 to 9.

[Formula 1]

1.0? Bs / As? 10.0

(In the above formula 1, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B)

[Formula 2]

0.1? Bs? As? 0.9

(In the formula 2, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B.)

[Formula 3]

0.12? Bw / Aw? 1.5

(Where Aw is the content of the inorganic particles A and Bw is the content of the inorganic particles B).

And an effective projection for suppressing formation of coarse projections due to secondary agglomeration in the range satisfying all of the above formulas 1 to 3 so as to smooth the surface of the film but to improve post-processing handling and windability of the film, Opacity can be increased to avoid revealing non-intrinsic defects such as appearance that can occur during processing. In addition, pinhole generation and MLCC short defect rate due to surface roughness transfer can be reduced.

It is preferable that the film surface is smooth while the inorganic particles A and the inorganic particles B are mixed in a range of an average particle diameter of 0.1 to 1.0 占 퐉, more specifically 0.2 to 0.8 占 퐉, more specifically 0.3 to 0.5 占 퐉, A film can be produced.

Further, it is preferable since the true specific gravity of the inorganic particle mixture is in the range of 2.1 or less, more specifically 1.8 to 2.1, because the distribution of particles per unit area is increased to prevent film blocking and to increase the opacity and improve the appearance quality .

Further, the pH of the inorganic particle mixture may be 6 to 9. More specifically, it may have a pH of 6.5 to 7.5. In this range, it is possible to prevent coarse protrusions due to re-agglomeration of the particles from occurring, and to increase the haze so as not to reveal non-essential appearance defects.

In one embodiment of the present invention, by using the true specific gravity and the pH of the inorganic particle mixture within the above range while using the inorganic particle mixture satisfying the above-mentioned formulas 1 to 3, the content of aggregated particles exceeding 1.0 占 퐉 is 0.02% Or less. More specifically, it may be 0.001 to 0.02%. The coarse protrusion can be reduced in the above range to obtain a flat surface when the film is produced, and it is possible to prevent the occurrence of defects such as pinholes due to the formation of effective protrusions.

More specifically, for example, the inorganic particles A and the inorganic particles B may be independently selected from titanium dioxide, barium sulfate, calcium carbonate, magnesium carbonate, calcium phosphate, silica, alumina, talc and kaolin, Or may be composed of different inorganic particles.

More specifically, for example, the inorganic particles A may have an average particle diameter of 0.10 to 0.39 탆, more specifically 0.20 to 0.30 탆. The inorganic particles B may have an average particle diameter of 0.40 to 1.0 mu m, more specifically 0.5 to 0.8 mu m. In this range, the surface of the film is flat, and the effective protrusion for improving the post-processing handling and the winding-up property of the film is lowered, and the visibility of the appearance is lowered to increase the opacity so as not to reveal non-essential defects such as appearances in the post- More preferable, but not limited thereto.

More specifically, for example, the inorganic particles A may be silica having an average particle diameter of 0.1 to 0.39 탆, and the inorganic particles B may be silica having an average particle diameter of 0.40 to 1.0 탆. More specifically, the inorganic particle A is spherical silica having an average particle diameter of 0.1 to 0.39 탆, and the inorganic particle B is a spherical silica having an average particle diameter of 0.40 to 1.0 탆, but the present invention is not limited thereto.

In one embodiment of the present invention, the inorganic particle mixture may be contained in the polyester resin in an amount of 0.1 to 5% by weight. The dispersibility of the inorganic particles in the above range is excellent, but is not limited thereto.

In an embodiment of the present invention, the addition of the inorganic particle mixture in the form of a particle slurry dispersed in the glycol component during the synthesis of the polyester resin is effective because it is excellent in dispersibility and can prevent re-aggregation between particles, It is not. That is, it may be added after the end of the esterification reaction or the transesterification reaction but before the start of the polycondensation reaction, but is not limited thereto.

Another aspect of the invention is a polyester film. The polyester film according to an embodiment of the present invention includes inorganic particles A and inorganic particles B satisfying the following formulas 1 to 3 and has an average particle size of 0.1 to 1.0 Mu m, a true specific gravity of 2.1 or less, an inorganic particle mixture having a pH of 6 to 9 in an amount of 0.05 to 1 wt%

The average surface roughness is 10 nm or less, the maximum peak height surface roughness is 100 nm or less, the peak count is 1 to 10 pieces / mm 2, the haze is 7 to 10%, and the winding yield is 65% or more.

[Formula 1]

1.0? Bs / As? 10.0

(In the above formula 1, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B)

[Formula 2]

0.1? Bs? As? 0.9

(In the formula 2, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B.)

[Formula 3]

0.12? Bw / Aw? 1.5

(Where Aw is the content of the inorganic particles A and Bw is the content of the inorganic particles B).

In one embodiment of the present invention, the content of the inorganic particle mixture may be 1000 to 3500 ppm, specifically 1500 to 3000 ppm, more specifically 2000 to 2500 ppm, of the total weight of the film. In the case of a coextruded multilayer film, when the particles are contained only in the skin layer, the content of the particles used in the skin layer may be the same as the above range. Or when the particles are contained in both the skin layer and the core layer, the content of the particles in the whole film may satisfy the above range. It is preferable to reduce the surface roughness in the above range and at the same time to satisfy the winding property and the running property so as to provide a film with improved productivity.

In one embodiment of the present invention, the polyester film may have a surface roughness peak count (Pc) satisfying the following formula (4).

[Formula 4]

1? Pc? 10

In the formula (4), Pc is the number of peaks per unit area, and the unit is ea / mm < 2 >.

It is preferable to reduce the surface roughness in the above range and at the same time to satisfy the winding property and the running property so as to provide a film with improved productivity.

In one embodiment of the present invention, the polyester film has a centerline average surface roughness Ra of 10 nm or less as measured by applying a 0.08 mm cut-off value using a contact type three-dimensional surface roughness meter, Rp is 100 nm or less, the peak count Pc is 1 to 10 / mm 2, the haze is 7 to 10%, and the winding yield is 65% or more.

Specifically, the center line average surface roughness Ra may be 1 to 10 nm, and the maximum peak height Rp at the surface center line may be 10 to 100 nm. But it is not limited thereto since it is possible to provide a film having excellent smoothness due to a low surface roughness within the above range.

In addition, effective protrusions necessary for securing the winding property and running property of the film can be achieved within a range satisfying all the properties that the peak count Pc is 1 to 10 pieces / mm 2, the haze is 7 to 10%, and the winding yield is 65% It is preferable since it is possible to lower the visibility of the appearance so as not to expose non-essential defects such as appearance that may appear in the processing of the process.

In one embodiment of the present invention, the polyester film may have a thickness of 20 to 40 mu m. But is not limited to, the range of application to base films of release films in this range. The polyester film used as the base film of the release film for MLCC has a tendency to be continuously thinned. When the thickness of the film is more than 40 탆, the environmental load becomes large when it is discarded after use, However, when the thickness is less than 20 탆, it is difficult to maintain the rigidity of the base film in the coating and releasing operations of the green sheet, thereby causing a problem that the processing defects increase. Therefore, the above range is preferred, no.

In one embodiment of the present invention, the polyester film may further comprise a release layer on one or both sides. The release layer may be such that a silicone release layer is formed from the viewpoint of allowing the applied layer to be evenly applied when the ceramic slurry or the like is applied, while allowing the release layer to be easily peeled off. The release layer can be used without limitation as long as it is usually applied to the release layer in the release film field of a film for an electronic material.

In one embodiment of the present invention, the polyester film may be a biaxially stretched film. Specifically, the polyester film may be biaxially stretched 3 to 5 times in the machine direction and 4 to 6 times in the width direction. The thermal dimensional stability of the polymer structure in the stretching ratio is further increased to reduce heat shrinkage, which is preferable, but is not limited thereto.

In one embodiment of the present invention, the polyester film may be heat-treated at 200 to 250 ° C and 1 to 10% relaxed after biaxial stretching. Specifically, it may be one which imparts relaxation simultaneously with the heat treatment, more specifically, 1 to 10%, more specifically, 2 to 4% relaxation in the width direction. In the above range, the film is maintained in a state of being tensed in the width direction, thereby increasing the compactness of the polymer structure and reducing the deformation due to heat, but is not limited thereto.

Another aspect of the present invention is a method for producing a polyester resin. More specifically, in a method for producing a polyester resin,

Wherein the inorganic particles A and the inorganic particles B satisfy the following formulas 1 to 3 and have an average particle diameter of 0.1 to 1.0 占 퐉, a true specific gravity of 2.1 or less and a pH Is 6 to 9 is dispersed in ethylene glycol may be added after the completion of the esterification reaction or the transesterification reaction until the start of the polycondensation reaction.

[Formula 1]

1.0? Bs / As? 10.0

(In the above formula 1, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B)

[Formula 2]

0.1? Bs? As? 0.9

(In the formula 2, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B.)

[Formula 3]

0.12? Bw / Aw? 1.5

(Where Aw is the content of the inorganic particles A and Bw is the content of the inorganic particles B).

In one embodiment of the present invention, the polyester resin may be one prepared by including an ester exchange reaction step and a polycondensation reaction step. Further, it may be prepared by further comprising a solid phase polymerization step after the polycondensation reaction step.

More specifically, the first aspect of producing the polyester resin of the present invention is

Mixing a dicarboxylic acid or an ester derivative thereof with a diol or an ester derivative thereof, and conducting an ester reaction to prepare a prepolymer; And

Adding a catalyst, an additive and an inorganic particle slurry to the preliminary polymerizate to perform a polycondensation reaction;

. ≪ / RTI >

The second aspect of producing the polyester resin of the present invention is

Mixing a dicarboxylic acid or its ester derivative with a diol or an ester derivative thereof, a catalyst and an additive, and conducting an ester reaction to prepare a prepolymer; And

Adding an inorganic particle slurry to the preliminary polymerizate to perform a polycondensation reaction;

. ≪ / RTI >

The third aspect of producing the polyester resin of the present invention may further include a step of performing solid phase polymerization after the polycondensation reaction of the first and second aspects.

In one embodiment of the present invention, the prepolymer may be a low molecular weight material (low molecular weight oligomer), more specifically BHET (bis-beta-hydroxyethyl terephthalate).

The preparation of the prepolymer is not limited but may be carried out at 230 to 270 ° C and may be carried out with water produced under pressure flowing out of the reactor. The reaction time may be, but not limited to, 1 to 10 hours, more preferably 2 to 6 hours.

In one embodiment of the present invention, the polycondensation reaction may be performed at 250 to 290 캜, though not limited thereto, and may be carried out under reduced pressure. The reaction time may be, but is not limited to, 3 to 5 hours.

In one embodiment of the present invention, the solid state polymerization is not limited but may be performed at 220 to 240 캜, and may be performed under reduced pressure. The reaction time may be, but not limited to, 5 to 20 hours, more specifically 6 to 18 hours.

Hereinafter, the present invention will be described in more detail based on examples and comparative examples. However, the following examples and comparative examples are merely examples for explaining the present invention in more detail, and the present invention is not limited by the following examples and comparative examples.

The following properties were evaluated as follows.

1) Average particle size

Using a particle size distribution analyzer (Beckman LS13 320).

2) True specific gravity of the particle slurry

The true specific gravity of the particle slurry was measured using a Pycnometer (Accupyc II 1340 from Shimadzu).

3) pH of the particle slurry

The pH of the particle slurry was measured using a pH meter (PC2700 from Eutech Instruments).

4) Coulter Counter of Particle Slurry

The aggregate particles (coarse particles) content exceeding 1 mu m in the particle slurry was measured using Multisizer 4e manufactured by Beckman. The mean value was calculated by repeating 6 times.

5) The haze of the polyester chip

The polyester resin composition prepared in the form of pellets was dissolved in orthochlorophenol using Haze Meter (NDH 5000, manufactured by Nippon Denshoku Industries Co., Ltd.), and haze was measured.

6) Surface roughness (Ra), maximum peak height surface roughness (Rp), and peak count (Peak count)

Using a three-dimensional surface roughness meter (Tokyoseimitsu, Surfcom 590A-3DF-12), the polyester film was cut into three portions at left, middle, and right according to JIS B0601 Under the conditions of a measurement speed of 0.03 mm / sec, a stylus radius of 2 탆, a load of 0.7 mm / N, a measurement area of 1.0 mm ² , and a cutoff value of 0.08 mm.

The surface roughness is calculated by the following equation when the center line is the x-axis and the vertical direction is the y-axis and the roughness curve is represented by y = f (x). The unit is nm.

(L: measurement length)

The highest peak height at the mean line was measured as the maximum peak height surface roughness (Rp). The number of peak peaks per unit area was defined as a peak count. The sum of the maximum mountain height surface roughness Rp and the depth to the lowest bone Rv is the maximum surface roughness Rmax.

That is, Rmax = Rp + | Rv |

7) The haze of the film

The prepared film was cut into a size of 5 cm x 5 cm and haze was measured using Haze Meter (NDH 5000, manufactured by Nippon Denshoku Industries Co., Ltd.).

8) Winding yield

The polyester film produced in the Examples and Comparative Examples was evaluated by calculating the amount of the product to be produced in terms of the input amount during the production.

Winding yield (%) = Product production / Input amount × 100

◎: When the yield is 65% or more

○: When the yield is 55 or more and less than 65%

B: When the yield is less than 55%

9) Intrinsic viscosity (IV; dl / g)

0.4 g of PET pellet (sample) was added to 100 ml of a reagent in which phenol and 1,1,2,2-tetrachloroethanol were mixed at a weight ratio of 6: 4, and the mixture was transferred to a Ubero's viscometer. For 10 minutes, and the falling seconds of the solution was determined using a viscometer and an aspirator. The number of drops of the solvent was also determined by the same method, and then the RV value and the I.V value were calculated by the following equation. In the following equation, C represents the concentration of the sample.

R.V. = Samples falling in water / solvent drops in seconds

[Example 1]

1) Production of polyester chips

50 parts by weight of ethylene glycol, 400 parts by weight of magnesium acetate, 200 parts by weight of calcium acetate and 150 parts by weight of antimony trioxide were added to 100 parts by weight of dimethyl terephthalate as an electrostatic peening agent and the mixture was stirred at room temperature to 230 DEG C for 4 hours The transesterification reaction was carried out to prepare a prepolymer BHET (bis-β-hydroxyethyl terephthalate). Methanol, which is a byproduct produced during the reaction, was flowed out of the reactor and separated through a distillation column. Ethylene glycol, which was generated after completion of the esterification reaction, was also separated through a distillation column. At this time, a particle slurry in which inorganic particles were dispersed in ethylene glycol was added to 1.0 wt% of the prepared BHET, 200 ppm of trimethyl phosphate was added as a heat stabilizer, and then the temperature was gradually raised to 285 DEG C and the pressure was reduced to 0.3 torr Respectively. A polyethylene terephthalate (PET) resin chip (hereinafter referred to as a "wet chip") having an intrinsic viscosity of 0.630 dl / g was prepared by carrying out a polycondensation reaction under high vacuum for 4 hours.

The particle slurry was prepared to have a particle concentration of 5% by weight and added. Two types of silica having an average particle diameter of 0.3 탆 and 0.5 탆 were charged and stirred to prepare a particle slurry.

2) Production of film

20 wt% of the polyethylene terephthalate resin chip and 80 wt% of a particle-free polyethylene terephthalate resin chip were blended and melt-extruded through an extruder, followed by quenching and solidification with a casting drum having a surface temperature of 20 ° C to produce a sheet Respectively. The sheet thus prepared was stretched 3.5 times in the machine direction and 4.0 times in the machine direction at 95 占 폚 and heat-treated at 230 占 폚 to prepare a biaxially oriented film having a final film content of 0.2 wt% and a thickness of 31 占 퐉. The physical properties of the prepared film were measured and are shown in Table 1 below.

[Examples 2 and 3]

A polyethylene terephthalate resin chip and a film were prepared in the same manner as in Example 1, except that the particle content, pH and true specific gravity were changed as shown in Table 1 below.

[Comparative Examples 1 to 6]

A polyethylene terephthalate resin chip and a film were prepared in the same manner as in Example 1, except that the particle content, pH and true specific gravity were changed as shown in Table 1 below.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Particle slurry Content ratio The inorganic particles A 70 50 50 100 100 0 100 90 30 Inorganic Particles B 30 50 50 0 0 100 0 10 70 True weight g / cm3 1.90 1.90 2.06 2.24 1.9 1.91 2.24 1.90 1.91 pH 6.5 6.5 8.8 9.9 6.4 6.5 3.4 6.4 6.5 Coarse particle content %, ≫ 1.0 [mu] m 0.005 0.014 0.016 0.028 0.020 0.037 0.047 0.005 0.019 Bs / As 1.67 1.67 1.67 - - - - 1.67 1.67 Bs-As 0.2 0.2 0.2 - - - - 0.2 0.2 Bw / Aw 0.43 One One 0 0 0 0 0.01 2.3 chip Hayes % 70.4 76.0 63.1 31.1 56.4 80.0 34.2 63.5 78.5 film thickness ㎛ 31 31 31 31 31 31 31 31 31 Ra nm 8 10 9 5 6 13 6 7 12 Rp nm 75 82 75 34 50 142 53 60 107 Rmax nm 100 123 116 63 84 211 98 87 160 Haze % 7.3 9.5 8.1 4.2 5.4 15.36 4.9 6.0 12.8 Pc / Mm2 1.0 2.0 1.5 0.0 0.0 5.0 0.1 0.5 3.0 Winding yield % ◎ ◎ ◎ △ ○ ◎ △ ○ ◎

As shown in Table 1, in Examples 1 to 3, the content of coarse particles was small, the peak count Pc indicating the effective projection was high, the average surface roughness Ra of the film was low, the maximum peak height surface roughness Rp was high, It was found that the film had a haze of 7 to 10%.

Claims (14)

Wherein the inorganic particles A and the inorganic particles B satisfy the following formulas 1 to 3 and have an average particle diameter of 0.1 to 1.0 占 퐉, a true specific gravity of 2.1 or less and a pH Is 6 to 9. The polyester resin according to claim 1,
[Formula 1]
1.0? Bs / As? 10.0
(In the above formula 1, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B)
[Formula 2]
0.1? Bs? As? 0.9
(In the formula 2, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B.)
[Formula 3]
0.12? Bw / Aw? 1.5
(Where Aw is the content of the inorganic particles A and Bw is the content of the inorganic particles B). The method according to claim 1,
Wherein said inorganic particle mixture has a content of aggregated particles exceeding 1.0 占 퐉 of 0.02% or less. The method according to claim 1,
The inorganic particles A and the inorganic particles B are each independently selected from titanium dioxide, barium sulfate, calcium carbonate, magnesium carbonate, calcium phosphate, silica, alumina, talc and kaolin. The method according to claim 1,
Wherein the inorganic particle mixture is contained in an amount of 0.1 to 5% by weight. The method according to claim 1,
The inorganic particles A are silica having an average particle diameter of 0.1 to 0.39 탆, and the inorganic particles B are silica having an average particle diameter of 0.40 to 1.0 탆. Wherein the inorganic particles A and the inorganic particles B satisfy the following formulas 1 to 3 and have an average particle diameter of 0.1 to 1.0 占 퐉, a true specific gravity of 2.1 or less and a pH Is from 6 to 9 in an amount of 0.05 to 1% by weight in the whole film,
A polyester film having an average surface roughness of 10 nm or less, a maximum peak height surface roughness of 100 nm or less, a peak count Pc of 1 to 10 pcs / mm 2, a haze of 7 to 10%, and a winding yield of 65% or more.
[Formula 1]
1.0? Bs / As? 10.0
(In the above formula 1, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B)
[Formula 2]
0.1? Bs? As? 0.9
(In the formula 2, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B.)
[Formula 3]
0.12? Bw / Aw? 1.5
(Where Aw is the content of the inorganic particles A and Bw is the content of the inorganic particles B). The method according to claim 6,
The inorganic particles A and the inorganic particles B are each independently selected from titanium dioxide, barium sulfate, calcium carbonate, magnesium carbonate, calcium phosphate, silica, alumina, talc and kaolin. The method according to claim 6,
Wherein the inorganic particles A are silica having an average particle diameter of 0.1 to 0.39 탆 and the inorganic particles B are silica having an average particle diameter of 0.40 to 1.0 탆. The method according to claim 6,
The polyester film is a biaxially stretched film having a thickness of 20 to 40 탆. In the method for producing a polyester resin,
Wherein the inorganic particles A and the inorganic particles B satisfy the following formulas 1 to 3 and have an average particle diameter of 0.1 to 1.0 占 퐉, a true specific gravity of 2.1 or less and a pH Is 6 to 9 is dispersed in ethylene glycol is added to the polyester slurry after the completion of the esterification reaction or the transesterification reaction until the start of the polycondensation reaction.
[Formula 1]
1.0? Bs / As? 10.0
(In the above formula 1, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B)
[Formula 2]
0.1? Bs? As? 0.9
(In the formula 2, As is the average particle diameter of the inorganic particle A and Bs is the average particle diameter of the inorganic particle B.)
[Formula 3]
0.12? Bw / Aw? 1.5
(Where Aw is the content of the inorganic particles A and Bw is the content of the inorganic particles B). 11. The method of claim 10,
Wherein a content of agglomerated particles exceeding 1.0 mu m in the particle slurry is 0.02% or less. 11. The method of claim 10,
Wherein the inorganic particles A and the inorganic particles B are each independently selected from titanium dioxide, barium sulfate, calcium carbonate, magnesium carbonate, calcium phosphate, silica, alumina, talc and kaolin. 11. The method of claim 10,
Wherein the content of the inorganic particle mixture in the polyester resin is 0.1 to 5% by weight when the particle slurry is added. 11. The method of claim 10,
Wherein the inorganic particles A are silica having an average particle diameter of 0.1 to 0.39 占 퐉 and the inorganic particles B are silica having an average particle diameter of 0.40 to 1.0 占 퐉.