KR20160052205A - White porous polyester film - Google Patents
White porous polyester film Download PDFInfo
- Publication number
- KR20160052205A KR20160052205A KR1020140152178A KR20140152178A KR20160052205A KR 20160052205 A KR20160052205 A KR 20160052205A KR 1020140152178 A KR1020140152178 A KR 1020140152178A KR 20140152178 A KR20140152178 A KR 20140152178A KR 20160052205 A KR20160052205 A KR 20160052205A
- Authority
- KR
- South Korea
- Prior art keywords
- particles
- resin
- film
- weight
- polyester film
- Prior art date
Links
Images
Abstract
The present invention relates to a white porous polyester film comprising (1) a polyester resin, (2) inorganic particles, and (3) polymer resin particles, wherein the polymeric resin particles are incompatible with the polyester resin, amorphous, Wherein the polymer resin particles are contained in an amount of 1 to 15% by weight based on the total weight of the film, and the polymer resin particles have a TGA (Thermogravimetric Analysis) of 280 DEG C And a weight loss rate of less than 10% when the film is allowed to stand for 2 hours.
Description
The present invention relates to a white porous polyester film excellent in optical properties, which is used for a backlight unit of an LCD or the like.
Recently, a liquid crystal display (LCD), which is one of the flat panel display devices, has advantages such as low power consumption, thin thickness and high resolution, and is widely used in notebooks, TVs, car navigation systems and the demand is also increasing. However, the LCD uses a light source called a back light unit (BLU) because it is a passive light emitting element rather than a self light emitting element, and a white porous polyester film is generally used as a reflector of the back light unit (BLU).
As a method for producing such a white porous polyester film, a method of producing a polyester film by blending a foaming agent into a polyester resin, a method of blending a polyolefin resin with a polyester resin to form micro voids on the surface and inside of the film And the like are known. However, the method using the foaming agent in the above method has a disadvantage in that it is very difficult to control the size uniformity of the foamed cell according to the processing temperature. The method of blending the polyolefin resin to form pores on the surface and inside of the film is a method of extrusion molding and drawing The uniformity of the pores is reduced due to poor compatibility in the course of passing through the substrate, and problems such as breakage occur in the drawing process, and whiteness, hiding power, and reflectance are insufficient.
Various compatibilizing agents have been added to solve these problems, but there are limitations in industrial application due to the problems such as lack of heat stability of the compatibilizing agent and migration to the surface.
To improve this, Korean Patent No. 10-0215496 discloses mixing polyester resin and polyolefin resin and further adding inorganic particles to sufficiently form porosity and pore size.
Korean Patent Laid-Open Publication No. 2011-0019614 discloses a white porous polyester film comprising a polyester resin, an inorganic particle, and a crystalline polymer resin that is incompatible with polyester. However, since such an incompatible material has a randomly sized dispersed phase and pores having a large size coexist with pores having a small size, process anxiety is caused, the number of pores per unit area is small and the desired reflectance can not be obtained, Is not uniform and is also limited in terms of physical properties.
In Korean Patent No. 10-1220225, crosslinked polymethylmethacrylate (PMMA) bead particles, which are monodispersed particles having a uniform particle size, are added to a PET film as a material which is incompatible with a polyester resin. However, depending on the physical properties of the PMMA bead particles, there is a problem that the pores are crushed after the film formation due to the temperature and pressure at the time of producing the film, or the reflectance is uneven.
Accordingly, an object of the present invention is to provide a white porous polyester film in which the shape of pores is maintained during the production of a film, and optical properties such as porosity, whiteness, hiding power and reflectivity are improved.
In order to achieve the above object, the present invention is a white porous polyester film comprising a polyester resin, an inorganic particle, and a polymer resin particle, wherein the polymer resin particle has (1) (4) is contained in an amount of 1 to 15% by weight based on the total weight of the film, (5) is thermogravimetric analysis (TGA: Thermogravimetric Analysis) at 280 DEG C for 2 hours.
Particularly, the polymeric resin particles are high-bridging beads exhibiting a weight reduction ratio of less than 10% when they are left standing at 280 ° C for 2 hours under thermogravimetric analysis (TGA), and the glass transition temperature (Tg) And a cross-linked bead having no or little shape change with a vertical / horizontal ratio of 1.0 to 2.0 is used.
The white porous polyester film of the present invention exhibits a weight reduction ratio of less than 10% at 280 DEG C for 2 hours in thermogravimetric analysis (TGA), and by using non-compatible cross-linked polymeric resin particles having a uniform particle distribution , It is easy to form uniform pores at the time of stretching, and the formed pores have little or no pore distortion during the production of the film. Therefore, the white porous polyester film of the present invention is excellent in process stability and product quality because of high reflectance and heat resistance, and particularly excellent in optical characteristics such as whiteness, hiding power and reflectance, and dimensional stability, And the like.
Fig. 1 shows the reflection effect of the two kinds of pores formed on the polyester film of the present invention and the resulting film by the polymer resin particles and the inorganic particles which are non-compatible with the polyester.
The white porous polyester film according to the present invention is a white porous polyester film comprising a polyester resin, inorganic particles, and polymer resin particles, wherein the polymeric resin particles are (1) non-compatible with the polyester resin and amorphous (2) an average particle diameter of 0.1 to 10 μm; (3) a crosslinked polymer resin particle; (4) 1 to 15% by weight based on the total weight of the film; : Thermogravimetric Analysis) at 280 ° C for 2 hours.
Particularly, the polymeric resin particles are high-bridged beads exhibiting a weight reduction ratio within 10% when they are left standing at 280 DEG C for 2 hours in thermogravimetric analysis. In other words, the polymeric resin particles exhibit a low weight reduction rate of less than 10%, whereas general polymethylmethacrylate (PMMA) resin particles show a weight loss rate of 10% or more (that is, a degree of degradation of 10% or more). Further, the polymeric resin particles use a high-bridged bead having no or little change in morphology with a vertical / horizontal ratio of 1.0 to 2.0 with no observed glass transition temperature (Tg) at 80 to 200 ° C.
The polyester resin used in the present invention is selected from the group consisting of a polyethylene terephthalate (PET) resin, a polyethylene naphthalate (PEN) resin or a blending resin thereof, and an acid component containing an aromatic dicarboxylic acid as a main component and an alkylene glycol as a main component Can be produced by polycondensation of a glycol component by a conventional method. Wherein the aromatic dicarboxylic acid is selected from the group consisting of terephthalic acid, terephthalic acid, isophthalic acid, dimethyl-2,5-naphthalenedicarboxylic acid, naphthalene dicarboxylic acid, cyclohexanedicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyldicarboxylic acid, diphenyl ether dicarboxylic acid, Anthracene dicarboxylic acid,?,? - bis (2-chlorophenoxy) ethane-4,4-dicarboxylic acid, and mixtures thereof. The alkylene glycol may also be selected from the group consisting of ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, hexylene glycol, and mixtures thereof.
In the white porous polyester film according to the present invention, the content of the polyester resin is preferably 60 to 90 parts by weight based on 100 parts by weight of the film. When the content of the polyester resin is 60 parts by weight or more, a smooth drawing process can be performed. When the content of the polyester resin is 90 parts by weight or less, an appropriate amount of an additive for controlling optical properties can be used. Because it is easy to manufacture.
In the white porous polyester film according to the present invention, inorganic particles can be added in a compounding manner for the purpose of controlling optical properties such as reflectance and color, and controlling friction coefficient, surface roughness and fine tactile sensation. The inorganic particles usable in the present invention may be selected from the group consisting of barium sulfate, titanium dioxide, calcium carbonate, kaolin, talc, zeolite, and mixtures thereof.
The average particle diameter of the inorganic particles is preferably in the range of 0.1 to 1.2 mu m. This is because when the average particle diameter of the inorganic particles is 0.1 to 1.2 탆, the optical characteristics and the surface characteristics of the film can be appropriately affected. More preferably, the average particle diameter of the inorganic particles is in the range of 0.3 to 0.9 占 퐉 or 0.5 to 0.7 占 퐉.
In the white porous polyester film according to the present invention, the content of the inorganic particles is preferably 9 to 30 parts by weight based on 100 parts by weight of the film. When the content of the inorganic particles is 9 parts by weight or more, the effect of addition of the inorganic particles can be suitably realized. When the content of the inorganic particles is 30 parts by weight or less, excellent process stability can be obtained, sufficient stretching magnification can be realized, Properties can be implemented.
In the white porous polyester film according to the present invention, polymeric resin particles may be further added in order to form uniform and efficient pores in the present invention.
The polymeric resin particles are preferably crosslinked to improve heat resistance. When the non-crosslinked general polymer resin particles are added during the film extrusion process, the polymer resin may not retain the extrusion temperature of the film, and the size of the dispersed phase is not uniform and the reflectance is decreased. On the other hand, when crosslinked polymer resin particles are used, since the polymer resin particles are crosslinked, they can withstand the extrusion temperature of the film, so that they do not cause problems in heat resistance and maintain the size of the dispersed phase uniformly. The crosslinked polymer resin particles exhibit no glass transition temperature (Tg). For example, when a differential scanning calorimetry (DSC) is measured for a general PMMA resin, the glass transition temperature is 95 To 100 < 0 > C, whereas the crosslinked PMMA particles do not show a glass transition temperature even when DSC is measured.
In addition, the polymeric resin particles are less thermally decomposed even at a high temperature, so that sufficient pores can be formed in the production of a film, and thus the optical properties such as reflectivity can be improved.
The polymeric resin particle preferably has a vertical / horizontal ratio in the range of 1.0 to 2.0 on the film, and preferably has little or no shape change. When the morphological change is large, there is a problem that the pores are crushed or the pores are not formed uniformly in the film, so that the optical characteristics such as the reflectivity may be deteriorated or become uneven.
The average particle diameter (D50) of the polymer resin particles is preferably 0.1 to 10 mu m. This is because when the average particle diameter is 0.1 탆 or more, dispersion of the particles and workability in a compounding process can be advantageous, and when the average particle diameter is 10 탆 or less, there is an advantage in drawing processability. More preferably an average particle diameter of 0.5 to 5 占 퐉, and most preferably 0.5 to 0.8 占 퐉 . Particularly, monodisperse particles having a uniform particle size are preferred, and for example, particle size dispersion is preferably 0.7 to 0.8.
The polymer resin particles may be particles of a resin crosslinked as a polymethyl methacrylate (PMMA) resin or a copolymer resin thereof, a polystyrene (PS) resin or a copolymer resin thereof, or a cyclic olefin copolymer resin (COC) Crosslinked PMMA resin particles or crosslinked PMMA copolymer resin particles are preferred. PMMA resins have excellent optical properties and are low in surface affinity with PET, which is advantageous for pore formation.
When such polymeric resin particles crosslinked and excellent in heat resistance and monodispersed are added together with inorganic particles at the time of film production, a dispersed phase evenly dispersed in the PET can be generated similarly to the continuous phase . That is, since the particles of small size and uniformity are dispersed in the PET, the pore size formed after stretching is small and uniform, and the number of the pores is increased, so that the reflectance is improved and a uniform reflectance can be obtained. In addition, since the particle size is small and the pore size is small, high-magnification drawing is possible, and the drop off and deformation of the particles during drawing are reduced, thus improving the processability. In addition, since it is not necessary to add additional additives such as a dispersant, the process can be simplified.
In the white porous polyester film according to the present invention, the content of the polymeric resin particles is preferably 1 to 15 parts by weight based on 100 parts by weight of the film. If the content is too small, the effect of the addition may be insignificant. When the content is 15 parts by weight or less, the film is advantageous in the stability of the film-forming process, the stretching magnification can be sufficiently realized, and optical characteristics excellent in reflectance and the like can be realized. More preferably, the content of the polymeric resin particles is 1 to 10 parts by weight.
The resin layer of the polyester film according to the present invention may further contain a whitening agent, a stabilizer, a polycondensation catalyst, a dispersing agent, an electrostatic agent, a crystallization accelerator, an antiblocking agent, a lubricant, and the like in addition to the main components as necessary.
The polyester film according to the present invention can be laminated in two or more layers. In particular, a protective layer may be formed on one side or both sides of the layer containing the resin particles in order to prevent the resin particles from falling off from the layer containing the polymeric resin particles.
The protective layer is made of a polymer resin, and the polymer resin is preferably a transparent resin such as a polyester-based or an acrylic-based resin, but is not limited thereto. The protective layer may be formed by a known method such as coextrusion or coating.
In addition to the polymer resin, the protective layer may include inorganic particles for increasing the reflectivity. The inorganic particles may be at least one selected from the group consisting of SiO 2 , TiO 2 and BaSO 4 . Further, the inorganic particles, it is preferable to use the other inorganic particles and SiO 2 together. The inorganic particles may be used in an amount of not more than 20 parts by weight based on 100 parts by weight of the polymer resin within a range that does not impair optical properties.
Thus, in the white porous polyester film according to the present invention, two kinds of pores are formed by adding non-compatible cross-linked polymeric resin particles together with inorganic particles (see FIG. 1).
The two kinds of pores formed in the film can greatly improve the density of the total pores under the same area and can efficiently improve the scattering reflectance. As a result, not only the optical characteristics are improved, but also the phenomenon in which a bright line / dark line due to a lamp in a back light unit (BLU) appears can be solved.
The white porous polyester film of the present invention is excellent in whiteness degree, hiding power and weather resistance with a whiteness of 95% or more and a reflectance at 550 nm of 97% or more.
Further, the film of the present invention preferably has a density of 0.7 to 1.2 g / cm < 3 > in terms of light weight, and preferably has a film thickness of 50 to 500 mu m.
Hereinafter, the present invention will be described in more detail with reference to the following examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.
Production Example: Production of polyester resin
Dimethyl terephthalate and ethylene glycol were mixed in an equivalent ratio of 1: 2, and manganese acetate as an ester exchange catalyst was added to the mixture in an amount of 0.03 wt% to prepare bis-2-hydroxyethyl terephthalate as a monomer of polyethylene terephthalate .
0.05 wt% of antimony oxide was added as a polycondensation catalyst and polycondensation was completed to produce a polyester resin having an intrinsic viscosity of 0.66 dl / gr and a glass transition temperature of 78 캜.
Example 1: Preparation of white porous polyester film
The twin-screw extruder was charged with 89 wt% of the polyester resin, 10 wt% of barium sulfate having an average particle diameter of 0.6 mu m, and 1 wt% of highly crosslinked PMMA beads having an average particle size (D50) of polyester and an incompatible polymer resin Were mixed to prepare a chip.
This was dried, melted and extruded according to a conventional polyester film manufacturing method to prepare an unoriented sheet.
This was stretched three times in the longitudinal direction at 85 DEG C and further stretched three times in the transverse direction at 125 DEG C to prepare a biaxially stretched white porous polyester film having a thickness of 125 mu m.
Examples 2 to 6
A biaxially stretched film having a thickness of 125 탆 was produced in the same manner as in Example 1, except that the chips were produced with the mixed components and the contents shown in Table 1.
* Average particle size of BaSO 4 : 0.65 탆
* Average particle diameter of TiO 2 : 0.1 탆
* Average particle diameter of SiO 2 : 2.0 탆
* PMMA (A): High-bridged PMMA particles (glass transition temperature (Tg) not observed at 200 占 폚 or lower)
Comparative Examples 1 to 4
A biaxially stretched film having a thickness of 125 탆 was prepared in the same manner as in Example 1, except that chips were produced by the mixed components and the contents shown in Table 2.
PMMA (B): General PMMA particles (glass transition temperature (Tg) 97 DEG C)
PMMA (C): Normal crosslinked PMMA particles (glass transition temperature (Tg): 97 占 폚)
Test Example
The performances of the films prepared in the above Examples and Comparative Examples were evaluated by the following methods, and the results are shown in Table 3 below.
1) vertical / horizontal ratio of PMMA particles in film
SEM (scanning electron microscopy) analysis was performed to measure the average vertical / horizontal ratio of the particles on the cross section of the film.
2) Reflectance
The reflectance at 550 nm was measured using a spectrophotometer from Hunter Lab, USA. Also, the deviation of the reflectance was measured based on the measured average reflectance.
3) Fairness
The frequency of occurrence of film breakage during the manufacturing process of the film was evaluated.
?: Excellent,?: Fair, X: poor
In comparison of Examples 1, 3 and 4 and Comparative Example 3, it can be seen that the reflectivity increases as the content of the high-bridged PMMA increases, and the degree of improvement of the reflectivity decreases as the high-bridged PMMA content increases. However, in Comparative Example 3 in which the content of the high-bridged PMMA is 0.01%, the effect on the reflectance is inferior.
In the case of Comparative Example 2 using the uncrosslinked PMMA particles, the film could not be produced due to the impossibility of extrusion. In the case of Comparative Example 1 using a very small amount of uncrosslinked PMMA particles, the film could be produced by extrusion, It can be seen that the film formation is very poor due to the occurrence of bubbles or the like, and the effect remarkably deteriorates even in terms of the maximum reflectance and the reflectance uniformity. In the case of Comparative Example 4 using the ordinary crosslinked PMMA particles having a low degree of crosslinking, pores can be formed similarly to the embodiment, but not only the reflectance is lowered but also the fairness is very weak due to the heat resistance problem.
Claims (9)
(2) an average particle diameter of 0.1 to 10 μm; (3) particles of a crosslinked polymer resin; (4) the total weight of the film is (5) a weight percentage reduction of less than 10% when thermogravimetric analysis is performed at 280 DEG C for 2 hours in a thermogravimetric analysis.
Wherein the polyester resin is selected from the group consisting of a polyethylene terephthalate (PET) resin, a polyethylene naphthalate (PEN) resin and a blending resin thereof.
Wherein the inorganic particles are selected from the group consisting of barium sulfate, titanium dioxide, calcium carbonate, kaolin, talc, zeolite, and mixtures thereof, and the average particle size of the inorganic particles is 0.1 to 1.2 탆. Ester film.
Wherein the polymer resin particles have a vertical / horizontal ratio of 1.0 to 2.0, and the glass transition temperature (Tg) of the polymer resin particles is not observed at 80 to 200 占 폚.
Wherein the polymer resin particles have an average particle diameter of 0.5 to 5 占 퐉 and a particle diameter dispersion degree of 0.7 to 0.8.
Wherein the polymeric resin particles are crosslinked polymethyl methacrylate (PMMA) resin particles or cross-linked PMMA copolymer resin particles.
Wherein the content of the polyester resin is 60 to 90 parts by weight, the content of the inorganic particles is 9 to 30 parts by weight, and the content of the polymeric resin particles is 1 to 10 parts by weight, based on 100 parts by weight of the film , White porous polyester film.
A white porous polyester film, characterized in that the white porous polyester film further comprises a protective layer.
The protective layer is characterized in that it comprises an additional inorganic particles selected from the group consisting of SiO 2, TiO 2 and BaSO 4, the white porous polyester film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020140152178A KR20160052205A (en) | 2014-11-04 | 2014-11-04 | White porous polyester film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020140152178A KR20160052205A (en) | 2014-11-04 | 2014-11-04 | White porous polyester film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| KR20160052205A true KR20160052205A (en) | 2016-05-12 |
Family
ID=56024732
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020140152178A KR20160052205A (en) | 2014-11-04 | 2014-11-04 | White porous polyester film |
Country Status (1)
| Country | Link |
|---|---|
| KR (1) | KR20160052205A (en) |
-
2014
- 2014-11-04 KR KR1020140152178A patent/KR20160052205A/en active Search and Examination
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8999499B2 (en) | White porous polyester film and preparation method thereof | |
| KR100738900B1 (en) | White porous single layer polyester film and preparing method therefof | |
| CN106908863B (en) | Optical reflecting film and preparation method thereof | |
| KR101220225B1 (en) | White porous polyester film and preparation method thereof | |
| KR102078451B1 (en) | White polyester film and reflective sheet using the same | |
| KR102020532B1 (en) | Manufacturing method of white polyester reflective film, reflective film thereby, and reflective sheet using the same | |
| KR101955240B1 (en) | Reflective sheet for back light unit of liquid crystal display and manufacturing method thereof | |
| KR101450840B1 (en) | White porous polyester film and preparing method therefof | |
| KR101675350B1 (en) | White porous Polyester Film | |
| KR101574190B1 (en) | White polyester reflective film and method for manufacturing the same and reflective sheet using the same | |
| KR20160052205A (en) | White porous polyester film | |
| KR101561288B1 (en) | Low gloss white polyester film, method of manufacturing the same and reflective sheet thereof | |
| KR100721808B1 (en) | White porous single layer polyester film and preparing method therefof | |
| KR101523277B1 (en) | White porous multi-layer polyester film and preparation thereof | |
| KR101577367B1 (en) | White polyester film having improved dimensional stability and reflection sheet using the same | |
| KR101671817B1 (en) | White polyester film with low surface gloss and method of manufacturing the same and reflective sheet using the same | |
| JP2004361886A (en) | Reflection film and liquid crystal display device | |
| KR102248011B1 (en) | White polyester film and manufacturing method thereof | |
| KR101848452B1 (en) | Multilayer white porous polyester film | |
| KR20170096666A (en) | White porous polyester film and method for preparing the same | |
| JP2007023185A (en) | Aliphatic polyester resin reflecting film and reflecting plate | |
| KR102001118B1 (en) | MULTILAYERED WHITE POLYESTER FILM FOR REFLECTOR of LCD UNIT | |
| KR20150061173A (en) | White polyester reflective film and method for manufacturing the same | |
| KR20170002990A (en) | A reflective sheet containing glass bubbles | |
| KR101466346B1 (en) | Low hardness white polyester film |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A201 | Request for examination | ||
| E902 | Notification of reason for refusal | ||
| AMND | Amendment | ||
| E601 | Decision to refuse application | ||
| AMND | Amendment |