KR102539514B1 - Polyester film structure - Google Patents

Abstract

A polyester film structure according to embodiments of the present invention includes a first layer comprising a first resin layer and first particles dispersed in the first resin layer, and laminated on the first layer and comprising a second resin layer and a second resin layer. and a second layer including second particles dispersed in the resin layer. The difference between D ₉₀ and D ₁₀ in the particle size distribution of the second particles is 500 nm or less, and the sum of 10-point average roughness (Rz) of the first layer and the second layer is 200 nm or more. The polyester film structure can be used as a release film substrate for a green sheet forming process to improve process stability and reliability.

Description

Polyester film structure {POLYESTER FILM STRUCTURE}

The present invention relates to a polyester film structure. More specifically, it relates to a polyester film structure comprising a resin layer and particles dispersed in the resin layer.

In a process of manufacturing an electric device such as a multi-layered ceramic condenser (MLCC), a release film may be used as a carrier film for an intermediate process such as a thermal process. For example, a firing process and/or a forming process may be performed while a laminate including a ceramic layer before firing is moved on the release film in a green sheet state.

For example, a release film including a polyester substrate may be used as the carrier film. It is preferable that the release film is designed so as not to cause physical or mechanical deformation to the green sheet during the process while being easily peeled off from the green sheet where the molding process has been performed.

Meanwhile, as the size of the MLCC decreases recently, the thickness of the green sheet also decreases. Accordingly, the surface roughness of the polyester substrate may be easily transferred to the green sheet to cause deformation. However, when the surface roughness is excessively reduced, process easiness may deteriorate, such as occurrence of a blocking phenomenon.

Therefore, it is necessary to design a release film capable of improving the reliability of a process object such as a green sheet while reducing process defects.

For example, Korean Patent Registration No. 10-1976118 discloses a release film for manufacturing a green sheet.

Korean Registered Patent Publication No. 10-1976118

One object of the present invention is to provide a polyester release film structure that provides improved mechanical reliability and process stability.

A polyester film structure according to exemplary embodiments includes a first layer including a first resin layer and first particles dispersed in the first resin layer, and a second resin layer laminated on the first layer and the second resin layer and the first layer. and a second layer including second particles dispersed in the second resin layer. The difference between D ₉₀ and D ₁₀ in the particle size distribution of the first particles is 500 nm or less, and the sum of 10-point average roughness (Rz) of the first layer and the second layer is 200 nm or more.

In some embodiments, the difference between D ₉₀ and D ₁₀ of the first particle may be in the range of 100 to 400 nm.

In some embodiments, the first particle may include two or more types of particles having different particle sizes or materials.

In some embodiments, the difference in particle size (D ₅₀ ) between the two different types of particles included in the first particle may be 300 nm or less.

In some embodiments, the sum of 10-point average roughness (Rz) of the first layer and the second layer may be in the range of 200 to 500 nm.

In some embodiments, a surface of the first layer may be provided as a process running surface, and a surface of the second layer may be provided as a release coating surface.

A polyester film structure according to exemplary embodiments includes a first layer including a first resin layer and first particles dispersed in the first resin layer; and a second layer laminated on the first layer and including a second resin layer and second particles dispersed in the second resin layer. The sum of the 10-point average roughness (Rz) of the first layer and the second layer is in the range of 200 to 500 nm, and the sum of the center line average roughness (Ra) of the first layer and the second layer is in the range of 10 to 30 nm am.

In some embodiments, Ra and Rz of the second layer may be smaller than Ra and Rz of the first layer, respectively, and a maximum peak height surface roughness (Rp) of the second layer may be 100 nm or less.

In some embodiments, the particle size (D ₅₀ ) of the second particle is smaller than the particle size (D ₅₀ ) of the first particle, and the first particle may include two or more types of particles having different particle diameters or materials. there is.

In some embodiments, the sum of the 10-point average roughness (Rz) of the first layer and the second layer is in the range of 200 to 400 nm, and the center line average roughness (Ra) of the first layer and the second layer The sum may range from 15 to 25 nm.

According to the exemplary embodiments described above, the polyester film structure may have a multi-layer structure including a first layer having a process running surface and a second layer having a release coating surface. By adjusting the difference between D ₉₀ and D ₁₀ of the particles included in the second layer within a predetermined range, roughness uniformity may be improved while maintaining a predetermined surface roughness. Accordingly, through the first layer, winding stability and process stability may be simultaneously improved.

According to example embodiments, by maintaining the sum of the roughnesses of the first layer and the second layer within a predetermined range, low surface roughness through the second layer and process stability enhancement through the second layer may be realized together. there is.

In some embodiments, the second layer may include two or more types of organic particles having different particle sizes. Therefore, even if the roughness is relatively increased through the elastic properties of the organic particles, deformation of the object such as MLCC can be suppressed and sufficient process stability can be secured.

1 is a schematic cross-sectional view showing a polyester film structure according to exemplary embodiments.

Exemplary embodiments disclosed in this application include a polyester resin layer and particles, and provide a polyester release film structure having a multi-layer structure.

Hereinafter, embodiments of the present invention will be described in detail. However, since the present invention can have various changes and various forms, specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific form disclosed, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this application, they are not interpreted in an ideal or excessively formal meaning. .

1 is a schematic cross-sectional view showing a polyester release film structure according to exemplary embodiments.

Referring to FIG. 1 , a polyester film structure 100 (hereinafter, may be abbreviated as a film structure) according to embodiments of the present invention may include a resin layer and organic particles dispersed in the resin layer.

In some embodiments, the film structure 100 may have a multi-layer structure including two or more layers. For example, as shown in FIG. 1 , the film structure 100 may include a first layer 110 and a second layer 120 stacked on the first layer 110 .

The first layer 110 may include a first resin layer 112 and first particles 114 dispersed in the first resin layer 112 . The second layer 120 may include a second resin layer 122 and second particles 124 dispersed in the second resin layer 122 .

The film structure 100 may include a first surface 100a and a second surface 100b. For example, the first surface 100a and the second surface 100b may correspond to the bottom and top surfaces of the film structure 100, respectively.

According to example embodiments, the second surface 100b may correspond to a release coating surface. For example, a release coating layer such as a silicon release layer may be formed on the second surface 100b and a multilayer ceramic capacitor (MLCC) green sheet may be stacked. The second surface 100b may be provided by the upper surface of the second layer 120 .

The first surface 100a may be a process running surface that moves in contact with transport equipment of green sheet firing/molding equipment. The first surface 100a may be provided by the bottom surface of the first layer 110 .

The first and second resin layers 112 and 122 may include a polyester resin. The polyester resin may be prepared through condensation polymerization of an aromatic dicarboxylic acid-based compound and a diol-based compound.

Examples of the aromatic dicarboxylic acid compound include dimethyl terephthalate, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, cyclobutanedicarboxylic acid, cyclohexanedicarboxylic acid, 5-sulfoisophthalic acid, 5-sulfope ropoxyisophthalic acid, diphenyldicarboxylic acid, diphenoxyalkanedicarboxylic acid, adipic acid, sebacic acid, and the like. Preferably, dimethyl terephthalate or terephthalic acid may be used.

Examples of the diol-based compound include alkylene glycol-based compounds such as ethylene glycol, 1,3-propanediol, and 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, and 1,4-cyclohexanediol. methanol and the like. Preferably, ethylene glycol may be used.

According to example embodiments, the first and second particles 114 and 124 may include organic or inorganic particles. The organic particles may include cross-linked organic resin particles, such as silicone resin, cross-linked divinylbenzene polymethacrylate, cross-linked polymethacrylate, cross-linked polystyrene resin, benzoguanamine-formaldehyde resin, and benzoguanamine. - Melamine-formaldehyde resin, melamine-formaldehyde resin, etc. can be used. In a preferred embodiment, a cross-linked polystyrene (PS) resin may be included as the organic particles. For example, the organic particles may include spherical polystyrene resin particles.

The inorganic particles may include, for example, silica (SiO ₂ ), titania (TiO ₂ ), zeolite, barium sulfate, calcium carbonate, and the like.

In a preferred embodiment, the first and second particles 114 and 124 may include a cross-linked polystyrene (PS) resin. For example, the first and second organic particles 114 and 124 may include spherical polystyrene resin particles.

In some embodiments, the second particles 124 included in the second layer 120 include inorganic particles such as silica, and the first particles 114 included in the first layer 110 include PS resin. It may contain organic particles such as particles.

For example, the first and second particles 114 and 124 may be added in the form of a slurry dispersed in a diol-based compound (eg, ethylene glycol) during synthesis of a polyester resin.

The first particles 114 included in the first layer 110 may include particles having a plurality of different particle sizes (eg, different D ₅₀ ). Accordingly, the uniformity of the surface roughness of the entire first surface 100a may be further improved by further improving the dispersibility of the organic particles in the first resin layer 112 .

According to example embodiments, the difference between D ₉₀ and D ₁₀ in the particle size distribution of the first particles 114 may be about 500 nm or less. When the difference between D ₉₀ and D ₁₀ exceeds about 500 nm, particle size distribution deviation is excessively increased, and thus roughness uniformity is lowered, and winding stability of the film structure 100 is lowered, and film wrinkles and blocking may be caused.

Preferably, the difference between D ₉₀ and D ₁₀ of the first particles 114 may be about 50 to 500 nm, more preferably about 100 to 400 nm. Within the above range, sufficient winding stability and uniformity of roughness may be promoted.

D ₉₀ and D ₁₀ values can be measured through a cumulative distribution curve of the powder through a particle size analyzer.

As described above, the first particles 114 included in the first layer 110 may include a mixture or blend of two or more types of particles having different particle sizes. In some embodiments, a particle size difference (eg, D ₅₀ difference) between different particles in the mixture may be about 300 nm or less. Within the above range, it is possible to prevent defects (eg, partial wrinkles, partial tearing, green sheet pressing, etc.) due to non-uniformity of film properties due to an increase in particle size difference.

Preferably, the difference in particle size between the different particles can be controlled in the range of about 100 to 300 nm.

As described above, the second surface 100b of the second layer 120 may be provided as a release coating surface and a laminated surface of the MLCC green sheet. Accordingly, the particle size of the second particle 124 may be smaller than that of the first particle 114 .

In some embodiments, the particle size of the first particle 114 may be about 0.3 to 1.5 μm. Preferably, the particle size of the first particles 114 may be about 0.3 to 1 μm, more preferably about 0.3 to 0.6 μm.

In some embodiments, the particle size of the second particle 124 may be about 0.05 to 0.3 μm. Preferably, the particle size of the second organic particles 124 may be about 0.1 to 0.3 μm.

According to exemplary embodiments, the content of the first particles 114 in the first layer 110 may be greater than or equal to the content of the second particles 124 in the second layer 120 . Preferably, the content of the first particles 114 may be greater than the content of the second particles 124.

For example, the content of the first particles 114 in the first layer 110 may be about 2000 to 5000 ppm, and the content of the second particles 124 in the second layer 120 is about 1000 to 2000 ppm can be

The surface roughness (eg, Ra and Rz) of the first surface 100a of the film structure 100 may be greater than that of the second surface 100b. Accordingly, transfer of the illumination to the green sheet may be prevented through implementing low illumination on the second surface 100b on which the MLCC green sheets are stacked, and deformation of the green sheet may be prevented.

In addition, by relatively increasing the surface roughness of the first surface 100a, it is possible to ensure process drivability and process control characteristics through the first surface 100a. When the film structure 100 is supplied in a wound state, winding stability and anti-blocking properties may also be improved through the relatively high roughness of the first surface 100a.

According to example embodiments, the sum of center line average roughnesses Ra of the first surface 100a and the second surface 100b may be in a range of about 10 nm to about 30 nm. In addition, the sum of the 10-point average roughness (Rz) of the first surface 100a and the second surface 100b is about 200 nm or more, and in one embodiment, may be in the range of 200 to 500 nm.

By maintaining the sum of the surface roughnesses of the first surface 100a and the second surface 100b within the above range, the total roughness value decreases excessively while suppressing the deformation of the green sheet due to the excessive increase in the total roughness value. It is possible to suppress the blocking phenomenon, green sheet peeling defect, etc. that occur in the case of

Accordingly, it is possible to more effectively control defects of the green sheet and secure process stability by considering the total roughness as well as adjusting the roughness of each resin layer.

In a preferred embodiment, the sum of center line average roughnesses (Ra) of the first surface 100a and the second surface 100b may be in the range of about 15 to 25 nm. In addition, the sum of 10-point average roughnesses (Rz) of the first surface 100a and the second surface 100b may be in the range of about 200 to 400 nm, in one embodiment, about 200 to 300 nm.

In one embodiment, the center line average roughness (Ra) of the second surface 100b may be in the range of about 3 to 10 nm. The center line average roughness (Ra) of the first surface 100a may be in the range of about 10 to 25 nm, preferably about 10 to 20 nm.

In one embodiment, the 10-point average roughness (Rz) of the second surface 100b may be in the range of about 50 to 150 nm. A 10-point average roughness (Rz) of the first surface 100a may be about 150 to 250 nm.

In some embodiments, the maximum peak height surface roughness Rp of the first surface 100a may be greater than the maximum peak height surface roughness Rp of the second surface 100b. For example, the maximum peak height surface roughness Rp of the second surface 100b may be about 100 nm or less. The maximum mountain height surface roughness Rp of the first surface 100a may exceed about 100 nm.

According to exemplary embodiments, the surface roughness of the first surface 100a may be relatively increased through the above-described particle size design of the first particles 114 while preventing the green sheet from being deformed or pressed.

In some embodiments, an organic particle including, for example, a cross-linked polystyrene resin may be used as the first particle 114 . Accordingly, while increasing the illuminance from the first surface 100a, transmission of the illuminance to the green sheet may be suppressed through the elastic property.

In addition, by controlling the overall roughness value of the film structure 100 in the above range, it is possible to manage process stability with higher reliability.

For example, the film structure 100 may be manufactured through co-extrusion. For example, after drying, melting, and extruding a polyester resin in which organic particles are dispersed for forming the first layer 110 and the second layer 120, respectively, through a die such as a multi-manifold die or a feed block die, Polyester resins can be incorporated. Thereafter, a sheet may be formed through a casting process, and the film structure 100 may be obtained through a stretching process.

As described above, the film structure 100 according to exemplary embodiments may be provided as a release film substrate for a green sheet forming process. For example, a release film may be formed by coating a solvent-type silicone resin on the second surface 100b of the film structure 100 and drying it with heat.

Examples and Comparative Examples

Example 1

1) Preparation of second layer resin

A silica particle slurry having a concentration of 2,000 ppm was prepared by dispersing spherical silica particles having an average particle diameter of 0.3 μm in ethylene glycol. After mixing ethylene glycol with dimethyl terephthalate in an equivalent ratio of 1:2, a transesterification reaction was performed by adding a transesterification catalyst to the mixture. Subsequently, the prepared silica particle slurry was added and a polycondensation catalyst was added to complete the polycondensation reaction, thereby preparing a polyester blend resin having an intrinsic viscosity of 0.66 dl/gr.

2) Preparation of the first layer resin

A silica particle slurry was prepared by dispersing spherical PS particles having an average particle diameter of 0.5 μm and spherical PS particles having an average particle diameter of 0.8 μm at a concentration of 2,000 ppm, respectively, in ethylene glycol. Thereafter, a polyester mixed resin for forming the first layer was prepared in the same manner as the second layer resin.

According to the co-extrusion polyester film manufacturing method, the polyester blend resin prepared above passes through the first layer resin and the second layer resin through respective drying, melting, and extrusion processes, and then joins them through a feed block die to form an abrasive drum. It was cast at room temperature on top and molded into a sheet form.

The molded sheet was stretched at a longitudinal stretch ratio of 3.4 times and a transverse stretch ratio of 3.5 times while heating to prepare a polyester film structure having a thickness of 30 μm.

Examples 2 to 4

A polyester film structure was prepared in the same manner as in Example 1, except that the particle composition (particle type, particle size, content, etc.) was changed as shown in Tables 1 and 2.

Comparative Examples 1 to 4

A polyester film structure was prepared in the same manner as in Example 1, except that the particle composition (particle type, particle size, content, etc.) was changed as shown in Tables 1 and 2.

Experimental example

(1) Measurement of surface roughness (Ra, Rz)

The surface roughness of the first and second surfaces of the polyester film structure was measured using an optical interferometric non-contact 3D roughness meter (Zygo NewView 9000 3D Optical Profiler). Specifically, the average value was obtained by measuring at 5 different locations, but the average value calculated after 3 repeated measurements at each location was used (a total of 15 measurements).

(2) Film wrinkle measurement

Under the LED light source, the polyester film structures of Examples and Comparative Examples were visually observed at an angle of 45 degrees to measure the number of wrinkles having a width of 1 cm or more. The occurrence of wrinkles was evaluated based on the following criteria.

○: No wrinkles observed

△: 2 or less wrinkles observed

X: 3 or more wrinkles observed

(3) Evaluation of blocking characteristics

After the film structures of Examples and Comparative Examples were left at room temperature for one week in a wound state, the occurrence of a blocking phenomenon was evaluated while the film structures were unwound again (○: No blocking, X: Blocking occurred)

(4) Evaluation of green sheet deformation

After coating the silicon release film on the second side of the film structures of Examples and Comparative Examples, a ceramic slurry in which barium titanate and polyvinylbutylene were mixed was applied to a thickness of about 2 μm and dried at 80 degrees. Thereafter, the release film was removed and local pressure marks were observed on the surface of the ceramic layer bonded to the second surface.

Specifically, the 3D roughness was measured for an area of 50 mm * 100 mm, and a portion having a change of 100 nm or more, that is, a portion including a deformation of 100 nm or more was defined as a deformed portion. The evaluation criteria are as follows.

○: deformation site not observed

△: 2 or less deformed parts observed

X: 3 or more deformed parts observed

The evaluation results are shown together in Table 1 and Table 2 below.

division Example 1 Example 2 Example 3 Comparative Example 1 particle
Furtherance 2nd floor
(heterogeneous
coated side) ingredient SiO ₂ SiO ₂ SiO ₂ SiO ₂ Particle size (D ₅₀ ) 0.3㎛ 0.1㎛ 0.3㎛ 0.1㎛ Content (ppm) 2000 2000 2000 2000 first floor
(process
driving side) ingredient PS PS SiO ₂ CaCO ₃ Particle size (D ₅₀ ) 0.3㎛ 0.3㎛ 0.3㎛ 1.1㎛ Content (ppm) 2000 2000 4000 4000 ingredient PS PS SiO ₂ - Particle size (D ₅₀ ) 0.5㎛ 0.5㎛ 0.5㎛ - Content (ppm) 2000 2000 4000 - Overall particle size distribution of the first layer (D ₉₀ -D ₁₀ ) 400 nm 400 nm 380 nm 3.5㎛ surface
illuminance 2nd floor
(heterogeneous
coated side) Ra (nm) 7 4 7 4 Rz (nm) 100 70 100 70 Rp (nm) 90 65 90 65 first floor
(process
driving surface) Ra (nm) 12 18 15 18 Rz (nm) 170 650 180 650 film wrinkles ○ ○ 3.3 ○ Blocking evaluation ○ ○ 2 ○ Green sheet deformation evaluation ○ ○ One X

division Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 particle
Furtherance 2nd floor
(heterogeneous
coated side) ingredient SiO ₂ SiO ₂ SiO ₂ SiO ₂ Particle size (D ₅₀ ) 0.1㎛ 0.3㎛ 0.1㎛ 0.5㎛ Content (ppm) 2000 2000 2000 4000 first floor
(process
driving surface) ingredient CaCO ₃ PS SiO ₂ CaCO ₃ Particle size (D ₅₀ ) 0.6㎛ 0.3㎛ 0.1㎛ 1.1㎛ Content (ppm) 2000 2000 2000 4000 ingredient CaCO ₃ PS SiO ₂ - Particle size (D ₅₀ ) 0.8 μm 0.8 μm 0.3㎛ - Content (ppm) 2000 2000 2000 - Overall particle size distribution of the first layer (D ₉₀ -D ₁₀ ) 3.2㎛ 1.2㎛ 320 nm surface
illuminance 2nd floor
(heterogeneous
coated side) Ra (nm) 4 7 4 13 Rz (nm) 70 100 70 180 Rp (nm) 65 90 65 160 first floor
(process
driving surface) Ra (nm) 16 15 7 18 Rz (nm) 550 430 90 650 film wrinkles ○ ○ X X Blocking evaluation ○ ○ X X Green sheet deformation evaluation X △ △ X

Referring to Tables 1 and 2, in the embodiments in which the surface roughness ranges of the first and second surfaces were maintained and the particle size characteristics in the first layer were controlled, as described above, the process stability of the film structure itself was improved. The deformation of the green sheet was also suppressed while being maintained. In the case of Comparative Examples 1 and 2, the sum of roughness increased excessively, causing deformation of the green sheet. Although the roughness of Comparative Example 3 was adjusted lower than that of Comparative Examples 1 and 2, the difference in particle size of the first layer increased, which also resulted in deformation of the green sheet. In the case of Comparative Example 4, the sum of the roughness was excessively reduced, resulting in defects after winding the film structure.

100: polyester film structure 110: first layer
112: first resin layer 114: first organic particles
120: second layer 122: second resin layer
124 second organic particle

Claims (10)

A first layer comprising a first resin layer and first particles dispersed in the first resin layer; and
A second layer laminated on the first layer and including a second resin layer and second particles dispersed in the second resin layer,
The difference between D ₉₀ and D ₁₀ in the particle size distribution of the first particles is 500 nm or less, and the sum of the 10-point average roughness (Rz) of the first layer and the second layer is 200 to 500 nm, polyester film structure. The polyester film structure according to claim 1, wherein the difference between D ₉₀ and D ₁₀ of the first particles ranges from 100 to 400 nm. The polyester film structure according to claim 1, wherein the first particle includes two or more types of particles having different particle sizes or materials. The method according to claim 3, Particle size (D ₅₀ ) difference between the two different types of particles included in the first particle is 300 nm or less, the polyester film structure. delete The polyester film structure according to claim 1, wherein the surface of the first layer is provided as a process running surface, and the surface of the second layer is provided as a release coating surface. A first layer comprising a first resin layer and first particles dispersed in the first resin layer; and
A second layer laminated on the first layer and including a second resin layer and second particles dispersed in the second resin layer,
The sum of the 10-point average roughness (Rz) of the first layer and the second layer is in the range of 200 to 500 nm, and the sum of the center line average roughness (Ra) of the first layer and the second layer is in the range of 10 to 30 nm Phosphorus, polyester film structure. The method according to claim 7, wherein Ra and Rz of the second layer are smaller than Ra and Rz of the first layer, respectively,
The polyester structure, wherein the maximum peak height surface roughness (Rp) of the second layer is 100 nm or less. The method according to claim 7, wherein the particle size (D ₅₀ ) of the second particle is smaller than the particle size (D ₅₀ ) of the first particle,
The first particle includes two or more types of particles having different particle diameters or materials, the polyester structure. The method according to claim 7, wherein the sum of the 10-point average roughness (Rz) of the first layer and the second layer is in the range of 200 to 400 nm, and the sum of the center line average roughness (Ra) of the first layer and the second layer is 15 to 25 nm range, a polyester film structure.

Images