KR20150075471A

KR20150075471A - Polyester resin composition and polyester film using thereof

Info

Publication number: KR20150075471A
Application number: KR1020130163465A
Authority: KR
Inventors: 정유인; 윤회원; 박지용
Original assignee: 코오롱인더스트리 주식회사
Priority date: 2013-12-26
Filing date: 2013-12-26
Publication date: 2015-07-06

Abstract

The present invention relates to a polyester resin composition for a release film of a multilayer ceramic capacitor and a polyester film using the polyester resin composition. More particularly, the present invention relates to a polyester resin composition for a release film, A polyester resin composition for a release film of a multilayer ceramic capacitor in which the surface roughness of a film is controlled by controlling the size of inert inorganic particles through classifying and filtering processes and is improved without coarse projections and fish eyes and a method for producing a film using the same .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin composition and a polyester film using the polyester resin composition.

In general, a polyester, particularly a polyethylene terephthalate (hereinafter referred to as PET), has excellent heat resistance, mechanical strength, transparency, and chemical resistance, and therefore is used for a film, a fiber, a container, a bottle, And the use and the amount of use thereof are continuously expanding at a lower price than other high-functional resins. The polyester film which is now industrially manufactured is widely used for various applications such as a base film for magnetic recording media, various packaging, protection of products, electronic materials, lamination, window, release, etc. Especially applied to laminated ceramic cones A releasing film based on a polyester film is widely used as a releasing film for green sheet molding.

In the case of a film used for release in such a display field, adhesion and removal of the film to an electronic material material in a post-process requires low surface roughness and uniform surface roughness control as well as defects of the base film. That is, when the smoothness of the film is poor, a slipping phenomenon occurs due to uneven tension in the production process of the base film, scratch defects or the like are generated on the surface of the film, and the coating amount is uneven in the post- Which may cause the value of the product to deteriorate.

In recent years, with the progress of miniaturization, high performance, and high precision of multilayer ceramic capacitors, the thickness of the release film itself also tends to become thinner. However, as the thickness of the release film, particularly the thickness of the release layer, becomes thin, the quality of the release film, particularly the surface roughness and defects of the release film, may cause breakage of the ceramic green sheet and pinholes, Quality is recognized as a very important factor.

In general, inorganic particles or organic polymer particles are used for the release layer in order to control the surface roughness of the release film. In this case, since the particle size of the release layer relative to the release layer of the thin film is relatively large, do. If the surface roughness of the release film is too low, the adhesion is excellent, but problems such as scratches are generated, and there is a high possibility that blocking or transfer may occur during the process, which causes a problem in the ceramic green sheet thin film process. On the other hand, when the illuminance of the release film is too high, there is a high possibility that pinholes and the like are generated due to the height difference of the surface.

Recently, a laminated release film using high performance oil and inorganic particles has been produced. However, since it has the advantage of imparting various functions through the lamination of high performance organic / inorganic particles, since different particles are distributed in each layer, There is a disadvantage that the recycling of recycled materials and raw materials is not smooth.

In the process of producing a film using a general polyester resin, an amorphous sheet formed by an extrusion die is passed through a plurality of rolls, wound in a roll of a roll through stretching, and then slitted. In order to pass or roll a plurality of rolls, In order to accomplish this, in general, it is possible to precipitate inner particles during polyester polymerization to impart irregularities, or to increase the processability by external addition of inert inorganic particles. However, when the internal precipitated particles are used, they are present in the polyester resin and act as internal defects, which can be a fatal point in use for high-quality optical films. In addition, when inorganic or organic particles added externally are added, process passability, for example, surface defects such as scratches on the surface of the film, prevention of wrinkling of the film wrapped on the roll, and detachment of the film are improved, High surface roughness and surface roughness deviation become large, and surface protrusions and fish eyes may generate smoothness and surface defects.

Accordingly, a polyester resin composition for a release film of a multilayer ceramic capacitor improved in surface roughness while maintaining the smoothness of the film and free from coarse projections and fish eyes has been studied.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art and provides a polyester resin composition having excellent smoothness, low surface roughness, less unevenness in roughness, and improved surface freeness due to coarse projections and fish eyes .

Another object of the present invention is to provide a polyester film suitable as a release film for an electronic material, particularly a release film of a multilayer ceramic capacitor, by using the above-mentioned polyester resin composition.

In order to achieve the above object, the present invention provides a polyester film for a release film comprising a polyester resin and inert inorganic particles, wherein the inert inorganic particles include a polyester resin composition whose particle size is controlled through classification and filtering processes Film.

The present invention relates to a polyester resin composition comprising calcium carbonate particles in which large particles having a particle diameter of 2 탆 or more are removed by classification treatment and filter treatment so that the particle size distribution ratio (γ) satisfies the following formula (1).

[Formula 1]

1??? 5

D90 is the diameter of the fine particle when the cumulative weight of the particles is 10 wt% based on the total weight, D90 is 90 wt% based on the total weight, Of the particle diameter.)

The present invention also relates to a polyester film produced by melt extrusion and stretching using the polyester resin composition.

The polyester resin composition of the present invention includes inorganic particles whose particle size is controlled by a classification and filtering process so that the dispersibility of the particles in the resin is enhanced and the frictional force of the film surface is lowered to produce coarse projections of the film, Can be improved and the film processability and scratching property can be improved even at a low surface roughness, so that the surface properties can be improved.

Hereinafter, preferred embodiments and evaluation test items of the polyester resin composition and the production method of the film of the present invention will be described in detail. The present invention can be more specifically understood by the following examples, and the following examples are for illustrative purposes only and are not intended to limit the scope of protection defined by the appended claims.

One aspect of the present invention is a polyester resin composition comprising calcium carbonate particles in which large particles having a particle size of 2 탆 or more are removed by classification treatment and filter treatment so that the particle size distribution ratio?

[Formula 1]

1??? 5

D90 is the diameter of the fine particles when the cumulative weight of the particles is 10% by weight based on the total weight, D90 is 90% by weight based on the total weight, Of the particle diameter.

When the particle size distribution is measured, D90 is always larger than D10, so that the particle size distribution ratio is 1 or more. When the particle size distribution ratio is more than 5, D90 means that large particles are distributed. The illuminance can be increased. Also, the more the difference between D90 and D10, the broader the particle size distribution, which may adversely affect the deviation of the surface roughness of the film. Therefore, a film having excellent surface roughness in the above range can be produced.

In one aspect of the present invention, in the production of a polyester resin, calcium carbonate particles having a maximum particle diameter of 2 탆 or more are classified and filtered to remove coarse particles by controlling the maximum particle diameter to 1.5-1.9 탆, . By controlling the particle size distribution ratio and the maximum particle size in this manner, it is possible to produce a film having a surface irregularity of the film lowered and a number of fish eyes of 1 or less.

The polyester film for a release film according to the present invention can be produced by blending a polyester base resin with calcium carbonate particles under a predetermined condition and then molding the film into a film. The properties of the film, such as the maximum particle diameter and the content of the calcium carbonate, Can be adjusted.

In general, the use of finely pulverized inorganic particles increases the number of effective peaks of the polyester film to prevent scratches and improve the running property. However, it is very important to regulate the size of the inorganic particles because the inorganic particles are too fine to form the protrusions of the surface, causing scratches and deteriorating the winding property. In the present invention, as the calcium carbonate particles in the inorganic particles, calcium carbonate particles whose maximum particle diameter is controlled to 2 탆 or less, preferably 1.5 to 1.9 탆 are used.

Techniques using inorganic particles to improve the surface roughness of the polyester film are known. However, in the present invention, the calcium carbonate particles are adjusted to the required physical properties of the film by classifying and filtering the particles, and then added to the polyester resin to form a low surface roughness of the film, The number of effective peaks of the film is increased to improve the processability, thereby improving the film production process and improving appearance problems such as scratches. In addition, due to the removal of coarse particles and the improvement of dispersibility, protrusions and fish eye generation due to large particles can be suppressed. In the case of amorphous silica particles which are widely used, it has been confirmed that even when subjected to classifying treatment and filter treatment, there is a limit in controlling the maximum particle size to 2 μm or less, and more aggregated particles are generated than calcium carbonate. In addition to classifying and filter treatment methods, there are particle milling methods or particle dispersing method in controlling particle size. Milling, however, causes re-agglomeration of particles due to changes in particle surface characteristics. In the case of adding a dispersing agent, And there is a problem of inducing aggregation of particles rather depending on the amount of the dispersant added.

The calcium carbonate particles according to the present invention are preferably contained in an amount of 0.5 to 2% by weight based on the total weight of the polyester resin. When the particle content in the resin is less than 0.5% by weight, the film content in the film is small when the film is applied to the film, and the film running property is poor and scratch defects or the like may occur on the film surface. When the particle content in the resin is more than 2% by weight, the slurry content of the calcium carbonate particles to be added in the polymerization step increases, and as a result, an excessive amount of ethylene glycol is added, which may cause side reactions, . Also, since the excessive amount of the particles may affect the degree of polymerization and the polymerization processability of the polymer, the amount of the charged particles is preferably 0.5 wt% to 2 wt% based on the total weight of the resin.

The polyester resin used in the present invention may be a polyester resin which is usually used for producing a polyester release film for a multilayer ceramic capacitor. For example, esterification of a dicarboxylic acid or an ester derivative thereof and a glycol or an ester derivative thereof Or a conventional homopolymeric polyester or copolymer polyester which can be prepared by an ester exchange reaction, for example, melt polycondensation.

The dicarboxylic acid or its ester derivative mainly uses terephthalic acid or its alkyl ester or phenyl ester, but a part of the dicarboxylic acid or an ester derivative thereof may be used, for example, as isophthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, diphenoxyethanedicarboxylic acid It may be used in substitution with a bifunctional carboxylic acid such as a carboxylic acid, an anthracenecarboxylic acid, an adipic acid, a sebacic acid, or a 5-naphthosulfonic acid isophthalic acid or an ester-forming derivative thereof. The glycol or the ester derivative thereof is a main object of ethylene glycol, but a part of the glycol or the ester derivative thereof may be used in combination with an organic solvent such as 1,3-propanediol, trimethylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, Dimethanol, neopentyl glycol, 1,4-bisoxyethoxybenzene, bisphenol, and polyoxyethylene glycol. Alternatively, a monofunctional compound or a trifunctional compound may be used in combination if the content is small.

The present invention includes the polyester film produced by melt extrusion and stretching using the above-described polyester resin composition.

More specifically, the method for producing the polyester film of the present invention can be produced according to the production method described below.

1) removing particles having a maximum particle diameter (dmax) of 2 μm or more through classification and filtering to obtain calcium carbonate particles having a maximum particle diameter of 1.5 to 1.9 μm and a particle size ratio (γ) Producing;

[Formula 1]

1??? 5

2) preparing a polyester resin composition comprising a slurry containing the calcium carbonate particles whose size is controlled as described above; And

3) melt-extruding the polyester resin composition to form a sheet, and then uniaxially or biaxially stretching to produce a film;

.

Specifically, in step 1), calcium carbonate particles having a maximum particle diameter of 2 탆 or more are classified and filtered to prepare calcium carbonate particle slurry whose maximum particle diameter is controlled to 1.5 to 1.9 탆. At this time, the maximum particle size of the particles can be controlled according to the required physical properties of the film, and it can be controlled by controlling the input flow rate of the particle slurry and the classification efficiency (fine particle: coagulant ratio) As shown in FIG.

In step 2), during the polyester polymerization, the slurry prepared above is added in such an amount that the content of the calcium carbonate particles is 0.5 wt% to 2 wt% or less based on the total weight of the polyester resin, . When the particle content in the resin is less than 0.5% by weight, the film content in the film is small when the film is applied to the film, and the film running property is poor and scratch defects or the like may occur on the film surface. When the particle content in the resin is more than 2% by weight, the slurry content of the calcium carbonate particles to be added in the polymerization process becomes large, and as a result, an excessive amount of ethylene glycol is added, which may cause side reactions, . Also, since the excessive amount of the particles may affect the degree of polymerization and the polymerization processability of the polymer, the amount of the charged particles is preferably 0.5 wt% to 2 wt% based on the total weight of the resin. At this time, the slurry means that calcium carbonate particles are dispersed in ethylene glycol.

In step 3), the resin composition prepared above is melt-extruded by a conventionally known T-die method to obtain an unstretched sheet, and the resulting unstretched sheet is stretched 2 to 7 times in the machine direction, Stretched 3 to 5 times, and then stretched 2 to 7 times, preferably 3 to 5 times, in the transverse direction with respect to the machine direction.

In addition, the total thickness of the produced films may be 1 to 30 占 퐉, and may be a single layer or multiple layers, and in the case of a polyester film laminated in several layers, at least one layer is made of the polyester film according to the present invention Lt; / RTI >

Further, it is preferable that in the film laminated with a single layer or a plurality of layers, calcium carbonate particles contained in at least one surface layer (outermost layer) are contained in the polyester film in an amount of 0.001 to 0.4 wt%. If the content of the particles in the film is less than 0.001% by weight, the smoothness and running property of the film may be poor, which may lead to a migration phenomenon during the production process, which may result in scratch defects or the like on the surface of the film. Also, when the particles in the film are used in an amount of more than 0.4% by weight, the running property of the film is improved, but the film surface roughness is increased due to a large number of particles of the film, and the probability of occurrence of fish eyes is increased, and satisfactory film properties may not be obtained.

The polyester resin and film of the present invention produced by the above production method is suitable for use as a release film for a high performance multilayer ceramic capacitor, and is excellent in smoothness and has a large protrusion and a fish eye, Can be used.

The polyester film for a release film according to the present invention has an average surface roughness (Ra) of less than 20 nm, more specifically 1 to 19 nm, and preferably 10 to 15 nm. When the Ra is 1 nm or less, the adhesion is excessively high, which may cause appearance problems such as scratches and pressing. Ra of 20 nm or more may act as a defect in the coating process.

Further, the maximum surface roughness (Rmax) of the polyester film for a release film according to the present invention is less than 500 nm, preferably 400 nm to 100 nm, and if it is 500 nm or more, . When the thickness is less than 100 nm, the adhesive force may deteriorate the film processability and cause appearance problems such as scratches and pressing.

It is preferable that the polyester film for a release film according to the present invention has one or more giant protrusions or fish eyes. If the number of fish eyes is more than one, deviation of the surface height of the film is caused, It may be transferred during the coating process and cause defective problems of the multilayer ceramic capacitor.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples.

The following properties were measured by the following measurement methods.

1) Particle size distribution ratio

D10 and D90 of the particle slurry were measured for particle size distribution ratio (γ) using a laser light scattering type particle size distribution analyzer (Beckman-Coulter, LS 13 320).

? = D90 / D10 Equation (1)

1??? 5

In the above formula (1), D10 is the diameter of the fine particles when the cumulative weight of the particles is 10% based on the total weight, and D90 is the particle diameter when the cumulative weight is 90% based on the total weight.

2) Film surface roughness and maximum surface roughness

The polyester film was cut into three portions on the left, middle, and right sides in accordance with JIS B0601, and then cut into pieces each having a size of 3 cm x 3 cm. Using a surface roughness meter manufactured by KOSAKA Co., Ltd., Two-dimensional surface roughness of at least five points on the surface of the film was measured to evaluate the average surface roughness Ra (nm) value.

(L: measurement length)

Speed: 0.05 mm / s

Cut off: 0.08㎜

Measurement length (L): 1.50 mm

The maximum surface roughness (Rmax) is measured using the same surface roughness meter, and represents the sum of the highest mountain height (Rp) in the average line and the depth (Rv) from the lowest bone.

That is, Rmax = Rp + Rv

3) Film running (coefficient of friction) measurement

The running property of the film was expressed by a dynamic friction coefficient, and the measurement thereof was carried out in accordance with ASTM D-1894. The measurement was carried out in an atmosphere of a temperature of 23 ± 1 ° C and a humidity of 50 ± 5% RH. The size of the sample used was 100 mm in width, 200 mm in length and tensile speed of 200 mm / min.

4) Fisheye measurement

Measure the number of Fisheye of 10 ㎛ or more by evaluating film samples taken from both sides and central part at 200 times transmission through optical microscope in slitted finished product.

[Example 1]

After dispersing calcium carbonate particles having a maximum particle diameter of 2.2 탆 in ethylene glycol at 25 wt%, the classification efficiency was adjusted so that the ratio of fine particles: coagulant was 9: 1 by weight using a classification apparatus to remove large particles of 2 탆 or more. Here, the fine particles mean particles having a maximum particle diameter of 1.9 탆 or less. Thereafter, a calcium carbonate particle slurry was prepared by additionally removing primary aggregated particles and foreign matters and macromolecules through a double-layered filter of 5 탆 and 2 탆.

After mixing 100 parts by weight of dimethyl terephthalate with 50 parts by weight of ethylene glycol, 400 ppm of transesterification catalyst magnesium acetate was added and the temperature was elevated from 140 ° C to 230 ° C for 4 hours to carry out transesterification reaction to obtain a prepolymer BHET (bis- β-hydroxyethyl terephthalate). Methanol generated during the reaction was separated through a distillation column, and ethylene glycol, which was generated after completion of the esterification reaction, was also separated through a distillation column. The prepared calcium carbonate slurry was added in an amount of 1.0% by weight based on the total weight of the polyester resin, 200 ppm of antimony trioxide as a polycondensation catalyst was added thereto, and the temperature was gradually raised from 230 ° C to 283 ° C and the polycondensation reaction was carried out under high vacuum of 0.3 torr for 4 hours To prepare a polyester resin having an intrinsic viscosity (IV) of 0.620 dl / g.

25% by weight of the polyester resin prepared above and 75% by weight of a particle-free polyester resin were blended and melt-extruded through an extruder, and then quenched and solidified by a casting drum having a surface temperature of 20 ° C to produce a sheet Respectively. The prepared polyester sheet was stretched 3.8 times in the longitudinal direction (MD) and 4.0 times in the transverse direction (TD), and then heat set at 238 ° C to prepare a biaxially oriented film of 30 μm thickness having a particle content of 2500 ppm in the final film.

The physical properties of the prepared film were measured and are shown in the following table.

[Example 2]

As shown in the following Table 1, a polyester film was prepared in the same manner as in Example 1, except that the particle size distribution ratio was changed to increase the particle classification efficiency and to change the granulation: granulation ratio, and physical properties were measured and shown.

[Example 3]

As shown in the following Table 1, a polyester film was prepared in the same manner as in Example 1, except that the calcium carbonate particles of the classification were passed through only a filter having a size of 5 mu m, and physical properties were measured and shown.

[Example 4]

As shown in the following Table 1, a polyester film was prepared in the same manner as in Example 1 except that the particle content in the film was changed, and physical properties were measured and shown.

[Comparative Example 1]

As shown in the following Table 1, a polyester film was prepared in the same manner as in Example 1, except that the calcium carbonate particles were not classified and filtered, and physical properties were measured and shown.

[Comparative Example 2]

As shown in the following Table 1, the fumed silica was subjected to classification under the same conditions as in Example 1 and post-treatment of 5 占 퐉 filter treatment to obtain silica particles having a particle size distribution ratio and Dmax adjusted, , And the physical properties thereof were measured and shown.

[Comparative Example 3]

As shown in the following Table 1, TiO ₂ particles were subjected to classification under the same conditions as in Example 1, and after the post-treatment of 5 μm filter treatment, the same as in Example 1, except that TiO ₂ whose particle size distribution ratio and Dmax were adjusted was used The polyester film was prepared and measured for its physical properties.

The properties of the polyester resin composition and the polyester film prepared in the above Examples and Comparative Examples were measured by the above physical property measuring method, and the results are shown in Table 1 below.

[Table 1]

As shown in Table 1, it was confirmed that the surface roughness, the maximum surface roughness, and the fish eye were both satisfied in the examples where coarse particles of 2 탆 or more were removed through classification of calcium carbonate and filter. In addition, as shown in Example 3, even when the content of particles was increased to 4000 ppm, only one fish eye was generated, and the optical characteristics were excellent.

In Comparative Example 1 in which the classification and filter treatment were not performed, it was confirmed that the surface roughness and the maximum surface roughness were high and fish eyes were generated.

In addition, as shown in Comparative Example 2 and Comparative Example 3, when inorganic particles other than calcium carbonate were used, the surface roughness and the maximum surface roughness could be controlled by classifying and filtering and adjusting the particle size. However, It was found that many children were inadequate to use.

Claims

Wherein the particle size distribution ratio (gamma) satisfies the following formula (1): " (1) "
[Formula 1]
1??? 5
D90 is the diameter of the fine particle when the cumulative weight of the particles is 10 wt% based on the total weight, D90 is 90 wt% based on the total weight, Of the particle diameter.)

The method according to claim 1,
Wherein the calcium carbonate particles have a maximum particle size (Dmax) size of 1.5 to 1.9 占 퐉.

The method according to claim 1,
Wherein the calcium carbonate particles are contained in an amount of 0.5 to 2% by weight of the polyester resin composition.

A polyester film produced by melt extrusion and stretching using the polyester resin composition of any one of claims 1 to 3.

5. The method of claim 4,
Wherein the polyester film contains 0.001 to 0.4% by weight of calcium carbonate particles in the total weight of the film.

5. The method of claim 4,
Wherein the polyester film has a surface roughness (Ra) of less than 20 nm and a maximum surface roughness (Rmax) of less than 500 nm.

5. The method of claim 4,
Wherein the polyester film is one or less fish eyes.